Change references of .c files to .cc files

ChangeLog:

	* MAINTAINERS: Rename .c names to .cc.

contrib/ChangeLog:

	* filter-clang-warnings.py: Rename .c names to .cc.
	* gcc_update: Likewise.
	* paranoia.cc: Likewise.

contrib/header-tools/ChangeLog:

	* README: Rename .c names to .cc.

gcc/ChangeLog:

	* Makefile.in: Rename .c names to .cc.
	* alias.h: Likewise.
	* asan.cc: Likewise.
	* auto-profile.h: Likewise.
	* basic-block.h (struct basic_block_d): Likewise.
	* btfout.cc: Likewise.
	* builtins.cc (expand_builtin_longjmp): Likewise.
	(validate_arg): Likewise.
	(access_ref::offset_bounded): Likewise.
	* caller-save.cc (reg_restore_code): Likewise.
	(setup_save_areas): Likewise.
	* calls.cc (initialize_argument_information): Likewise.
	(expand_call): Likewise.
	(emit_library_call_value_1): Likewise.
	* cfg-flags.def (RTL): Likewise.
	(SIBCALL): Likewise.
	(CAN_FALLTHRU): Likewise.
	* cfganal.cc (post_order_compute): Likewise.
	* cfgcleanup.cc (try_simplify_condjump): Likewise.
	(merge_blocks_move_predecessor_nojumps): Likewise.
	(merge_blocks_move_successor_nojumps): Likewise.
	(merge_blocks_move): Likewise.
	(old_insns_match_p): Likewise.
	(try_crossjump_bb): Likewise.
	* cfgexpand.cc (expand_gimple_stmt): Likewise.
	* cfghooks.cc (split_block_before_cond_jump): Likewise.
	(profile_record_check_consistency): Likewise.
	* cfghooks.h: Likewise.
	* cfgrtl.cc (pass_free_cfg::execute): Likewise.
	(rtl_can_merge_blocks): Likewise.
	(try_redirect_by_replacing_jump): Likewise.
	(make_pass_outof_cfg_layout_mode): Likewise.
	(cfg_layout_can_merge_blocks_p): Likewise.
	* cgraph.cc (release_function_body): Likewise.
	(cgraph_node::get_fun): Likewise.
	* cgraph.h (struct cgraph_node): Likewise.
	(asmname_hasher::equal): Likewise.
	(cgraph_inline_failed_type): Likewise.
	(thunk_adjust): Likewise.
	(dump_callgraph_transformation): Likewise.
	(record_references_in_initializer): Likewise.
	(ipa_discover_variable_flags): Likewise.
	* cgraphclones.cc (GTY): Likewise.
	* cgraphunit.cc (symbol_table::finalize_compilation_unit): Likewise.
	* collect-utils.h (GCC_COLLECT_UTILS_H): Likewise.
	* collect2-aix.h (GCC_COLLECT2_AIX_H): Likewise.
	* collect2.cc (maybe_run_lto_and_relink): Likewise.
	* combine-stack-adj.cc: Likewise.
	* combine.cc (setup_incoming_promotions): Likewise.
	(combine_simplify_rtx): Likewise.
	(count_rtxs): Likewise.
	* common.opt: Likewise.
	* common/config/aarch64/aarch64-common.cc: Likewise.
	* common/config/arm/arm-common.cc (arm_asm_auto_mfpu): Likewise.
	* common/config/avr/avr-common.cc: Likewise.
	* common/config/i386/i386-isas.h (struct _isa_names_table): Likewise.
	* conditions.h: Likewise.
	* config.gcc: Likewise.
	* config/aarch64/aarch64-builtins.cc (aarch64_resolve_overloaded_memtag): Likewise.
	* config/aarch64/aarch64-protos.h (aarch64_classify_address): Likewise.
	(aarch64_get_extension_string_for_isa_flags): Likewise.
	* config/aarch64/aarch64-sve-builtins.cc (function_builder::add_function): Likewise.
	* config/aarch64/aarch64.cc (aarch64_regmode_natural_size): Likewise.
	(aarch64_sched_first_cycle_multipass_dfa_lookahead): Likewise.
	(aarch64_option_valid_attribute_p): Likewise.
	(aarch64_short_vector_p): Likewise.
	(aarch64_float_const_representable_p): Likewise.
	* config/aarch64/aarch64.h (DBX_REGISTER_NUMBER): Likewise.
	(ASM_OUTPUT_POOL_EPILOGUE): Likewise.
	(GTY): Likewise.
	* config/aarch64/cortex-a57-fma-steering.cc: Likewise.
	* config/aarch64/driver-aarch64.cc (contains_core_p): Likewise.
	* config/aarch64/t-aarch64: Likewise.
	* config/aarch64/x-aarch64: Likewise.
	* config/aarch64/x-darwin: Likewise.
	* config/alpha/alpha-protos.h: Likewise.
	* config/alpha/alpha.cc (alpha_scalar_mode_supported_p): Likewise.
	* config/alpha/alpha.h (LONG_DOUBLE_TYPE_SIZE): Likewise.
	(enum reg_class): Likewise.
	* config/alpha/alpha.md: Likewise.
	* config/alpha/driver-alpha.cc (AMASK_LOCKPFTCHOK): Likewise.
	* config/alpha/x-alpha: Likewise.
	* config/arc/arc-protos.h (arc_eh_uses): Likewise.
	* config/arc/arc.cc (ARC_OPT): Likewise.
	(arc_ccfsm_advance): Likewise.
	(arc_arg_partial_bytes): Likewise.
	(conditionalize_nonjump): Likewise.
	* config/arc/arc.md: Likewise.
	* config/arc/builtins.def: Likewise.
	* config/arc/t-arc: Likewise.
	* config/arm/arm-c.cc (arm_resolve_overloaded_builtin): Likewise.
	(arm_pragma_target_parse): Likewise.
	* config/arm/arm-protos.h (save_restore_target_globals): Likewise.
	(arm_cpu_cpp_builtins): Likewise.
	* config/arm/arm.cc (vfp3_const_double_index): Likewise.
	(shift_op): Likewise.
	(thumb2_final_prescan_insn): Likewise.
	(arm_final_prescan_insn): Likewise.
	(arm_asm_output_labelref): Likewise.
	(arm_small_register_classes_for_mode_p): Likewise.
	* config/arm/arm.h: Likewise.
	* config/arm/arm.md: Likewise.
	* config/arm/driver-arm.cc: Likewise.
	* config/arm/symbian.h: Likewise.
	* config/arm/t-arm: Likewise.
	* config/arm/thumb1.md: Likewise.
	* config/arm/x-arm: Likewise.
	* config/avr/avr-c.cc (avr_register_target_pragmas): Likewise.
	* config/avr/avr-fixed.md: Likewise.
	* config/avr/avr-log.cc (avr_log_vadump): Likewise.
	* config/avr/avr-mcus.def: Likewise.
	* config/avr/avr-modes.def (FRACTIONAL_INT_MODE): Likewise.
	* config/avr/avr-passes.def (INSERT_PASS_BEFORE): Likewise.
	* config/avr/avr-protos.h (make_avr_pass_casesi): Likewise.
	* config/avr/avr.cc (avr_option_override): Likewise.
	(avr_build_builtin_va_list): Likewise.
	(avr_mode_dependent_address_p): Likewise.
	(avr_function_arg_advance): Likewise.
	(avr_asm_output_aligned_decl_common): Likewise.
	* config/avr/avr.h (RETURN_ADDR_RTX): Likewise.
	(SUPPORTS_INIT_PRIORITY): Likewise.
	* config/avr/avr.md: Likewise.
	* config/avr/builtins.def: Likewise.
	* config/avr/gen-avr-mmcu-specs.cc (IN_GEN_AVR_MMCU_TEXI): Likewise.
	* config/avr/gen-avr-mmcu-texi.cc (IN_GEN_AVR_MMCU_TEXI): Likewise.
	(main): Likewise.
	* config/avr/t-avr: Likewise.
	* config/bfin/bfin.cc (frame_related_constant_load): Likewise.
	* config/bpf/bpf-protos.h (GCC_BPF_PROTOS_H): Likewise.
	* config/bpf/bpf.h (enum reg_class): Likewise.
	* config/bpf/t-bpf: Likewise.
	* config/c6x/c6x-protos.h (GCC_C6X_PROTOS_H): Likewise.
	* config/cr16/cr16-protos.h: Likewise.
	* config/cris/cris.cc (cris_address_cost): Likewise.
	(cris_side_effect_mode_ok): Likewise.
	(cris_init_machine_status): Likewise.
	(cris_emit_movem_store): Likewise.
	* config/cris/cris.h (INDEX_REG_CLASS): Likewise.
	(enum reg_class): Likewise.
	(struct cum_args): Likewise.
	* config/cris/cris.opt: Likewise.
	* config/cris/sync.md: Likewise.
	* config/csky/csky.cc (csky_expand_prologue): Likewise.
	* config/darwin-c.cc: Likewise.
	* config/darwin-f.cc: Likewise.
	* config/darwin-sections.def (zobj_const_section): Likewise.
	* config/darwin.cc (output_objc_section_asm_op): Likewise.
	(fprintf): Likewise.
	* config/darwin.h (GTY): Likewise.
	* config/elfos.h: Likewise.
	* config/epiphany/epiphany-sched.md: Likewise.
	* config/epiphany/epiphany.cc (epiphany_function_value): Likewise.
	* config/epiphany/epiphany.h (GTY): Likewise.
	(NO_FUNCTION_CSE): Likewise.
	* config/epiphany/mode-switch-use.cc: Likewise.
	* config/epiphany/predicates.md: Likewise.
	* config/epiphany/t-epiphany: Likewise.
	* config/fr30/fr30-protos.h: Likewise.
	* config/frv/frv-protos.h: Likewise.
	* config/frv/frv.cc (TLS_BIAS): Likewise.
	* config/frv/frv.h (ASM_OUTPUT_ALIGNED_LOCAL): Likewise.
	* config/ft32/ft32-protos.h: Likewise.
	* config/gcn/gcn-hsa.h (ASM_APP_OFF): Likewise.
	* config/gcn/gcn.cc (gcn_init_libfuncs): Likewise.
	* config/gcn/mkoffload.cc (copy_early_debug_info): Likewise.
	* config/gcn/t-gcn-hsa: Likewise.
	* config/gcn/t-omp-device: Likewise.
	* config/h8300/h8300-protos.h (GCC_H8300_PROTOS_H): Likewise.
	(same_cmp_following_p): Likewise.
	* config/h8300/h8300.cc (F): Likewise.
	* config/h8300/h8300.h (struct cum_arg): Likewise.
	(BRANCH_COST): Likewise.
	* config/i386/cygming.h (DEFAULT_PCC_STRUCT_RETURN): Likewise.
	* config/i386/djgpp.h (TARGET_ASM_LTO_END): Likewise.
	* config/i386/dragonfly.h (NO_PROFILE_COUNTERS): Likewise.
	* config/i386/driver-i386.cc (detect_caches_intel): Likewise.
	* config/i386/freebsd.h (NO_PROFILE_COUNTERS): Likewise.
	* config/i386/i386-c.cc (ix86_target_macros): Likewise.
	* config/i386/i386-expand.cc (get_mode_wider_vector): Likewise.
	* config/i386/i386-options.cc (ix86_set_func_type): Likewise.
	* config/i386/i386-protos.h (ix86_extract_perm_from_pool_constant): Likewise.
	(ix86_register_pragmas): Likewise.
	(ix86_d_has_stdcall_convention): Likewise.
	(i386_pe_seh_init_sections): Likewise.
	* config/i386/i386.cc (ix86_function_arg_regno_p): Likewise.
	(ix86_function_value_regno_p): Likewise.
	(ix86_compute_frame_layout): Likewise.
	(legitimize_pe_coff_symbol): Likewise.
	(output_pic_addr_const): Likewise.
	* config/i386/i386.h (defined): Likewise.
	(host_detect_local_cpu): Likewise.
	(CONSTANT_ADDRESS_P): Likewise.
	(DEFAULT_LARGE_SECTION_THRESHOLD): Likewise.
	(struct machine_frame_state): Likewise.
	* config/i386/i386.md: Likewise.
	* config/i386/lynx.h (ASM_OUTPUT_ALIGN): Likewise.
	* config/i386/mmx.md: Likewise.
	* config/i386/sse.md: Likewise.
	* config/i386/t-cygming: Likewise.
	* config/i386/t-djgpp: Likewise.
	* config/i386/t-gnu-property: Likewise.
	* config/i386/t-i386: Likewise.
	* config/i386/t-intelmic: Likewise.
	* config/i386/t-omp-device: Likewise.
	* config/i386/winnt-cxx.cc (i386_pe_type_dllimport_p): Likewise.
	(i386_pe_adjust_class_at_definition): Likewise.
	* config/i386/winnt.cc (gen_stdcall_or_fastcall_suffix): Likewise.
	(i386_pe_mangle_decl_assembler_name): Likewise.
	(i386_pe_encode_section_info): Likewise.
	* config/i386/x-cygwin: Likewise.
	* config/i386/x-darwin: Likewise.
	* config/i386/x-i386: Likewise.
	* config/i386/x-mingw32: Likewise.
	* config/i386/x86-tune-sched-core.cc: Likewise.
	* config/i386/x86-tune.def: Likewise.
	* config/i386/xm-djgpp.h (STANDARD_STARTFILE_PREFIX_1): Likewise.
	* config/ia64/freebsd.h: Likewise.
	* config/ia64/hpux.h (REGISTER_TARGET_PRAGMAS): Likewise.
	* config/ia64/ia64-protos.h (ia64_except_unwind_info): Likewise.
	* config/ia64/ia64.cc (ia64_function_value_regno_p): Likewise.
	(ia64_secondary_reload_class): Likewise.
	(bundling): Likewise.
	* config/ia64/ia64.h: Likewise.
	* config/ia64/ia64.md: Likewise.
	* config/ia64/predicates.md: Likewise.
	* config/ia64/sysv4.h: Likewise.
	* config/ia64/t-ia64: Likewise.
	* config/iq2000/iq2000.h (FUNCTION_MODE): Likewise.
	* config/iq2000/iq2000.md: Likewise.
	* config/linux.h (TARGET_HAS_BIONIC): Likewise.
	(if): Likewise.
	* config/m32c/m32c.cc (m32c_function_needs_enter): Likewise.
	* config/m32c/m32c.h (MAX_REGS_PER_ADDRESS): Likewise.
	* config/m32c/t-m32c: Likewise.
	* config/m32r/m32r-protos.h: Likewise.
	* config/m32r/m32r.cc (m32r_print_operand): Likewise.
	* config/m32r/m32r.h: Likewise.
	* config/m32r/m32r.md: Likewise.
	* config/m68k/m68k-isas.def: Likewise.
	* config/m68k/m68k-microarchs.def: Likewise.
	* config/m68k/m68k-protos.h (strict_low_part_peephole_ok): Likewise.
	(m68k_epilogue_uses): Likewise.
	* config/m68k/m68k.cc (m68k_call_tls_get_addr): Likewise.
	(m68k_sched_adjust_cost): Likewise.
	(m68k_sched_md_init): Likewise.
	* config/m68k/m68k.h (__transfer_from_trampoline): Likewise.
	(enum m68k_function_kind): Likewise.
	* config/m68k/m68k.md: Likewise.
	* config/m68k/m68kemb.h: Likewise.
	* config/m68k/uclinux.h (ENDFILE_SPEC): Likewise.
	* config/mcore/mcore-protos.h: Likewise.
	* config/mcore/mcore.cc (mcore_expand_insv): Likewise.
	(mcore_expand_prolog): Likewise.
	* config/mcore/mcore.h (TARGET_MCORE): Likewise.
	* config/mcore/mcore.md: Likewise.
	* config/microblaze/microblaze-protos.h: Likewise.
	* config/microblaze/microblaze.cc (microblaze_legitimate_pic_operand): Likewise.
	(microblaze_function_prologue): Likewise.
	(microblaze_function_epilogue): Likewise.
	(microblaze_select_section): Likewise.
	(microblaze_asm_output_mi_thunk): Likewise.
	(microblaze_eh_return): Likewise.
	* config/microblaze/microblaze.h: Likewise.
	* config/microblaze/microblaze.md: Likewise.
	* config/microblaze/t-microblaze: Likewise.
	* config/mips/driver-native.cc: Likewise.
	* config/mips/loongson2ef.md: Likewise.
	* config/mips/mips-protos.h (mips_expand_vec_cmp_expr): Likewise.
	* config/mips/mips.cc (mips_rtx_costs): Likewise.
	(mips_output_filename): Likewise.
	(mips_output_function_prologue): Likewise.
	(mips_output_function_epilogue): Likewise.
	(mips_output_mi_thunk): Likewise.
	* config/mips/mips.h: Likewise.
	* config/mips/mips.md: Likewise.
	* config/mips/t-mips: Likewise.
	* config/mips/x-native: Likewise.
	* config/mmix/mmix-protos.h: Likewise.
	* config/mmix/mmix.cc (mmix_option_override): Likewise.
	(mmix_dbx_register_number): Likewise.
	(mmix_expand_prologue): Likewise.
	* config/mmix/mmix.h: Likewise.
	* config/mmix/mmix.md: Likewise.
	* config/mmix/predicates.md: Likewise.
	* config/mn10300/mn10300.cc (mn10300_symbolic_operand): Likewise.
	(mn10300_legitimate_pic_operand_p): Likewise.
	* config/mn10300/mn10300.h (enum reg_class): Likewise.
	(NO_FUNCTION_CSE): Likewise.
	* config/moxie/moxie-protos.h: Likewise.
	* config/moxie/uclinux.h (TARGET_LIBC_HAS_FUNCTION): Likewise.
	* config/msp430/msp430-devices.cc (extract_devices_dir_from_exec_prefix): Likewise.
	* config/msp430/msp430.cc (msp430_gimplify_va_arg_expr): Likewise.
	(msp430_incoming_return_addr_rtx): Likewise.
	* config/msp430/msp430.h (msp430_get_linker_devices_include_path): Likewise.
	* config/msp430/t-msp430: Likewise.
	* config/nds32/nds32-cost.cc (nds32_rtx_costs_speed_prefer): Likewise.
	(nds32_rtx_costs_size_prefer): Likewise.
	(nds32_init_rtx_costs): Likewise.
	* config/nds32/nds32-doubleword.md: Likewise.
	* config/nds32/nds32.cc (nds32_memory_move_cost): Likewise.
	(nds32_builtin_decl): Likewise.
	* config/nds32/nds32.h (enum nds32_16bit_address_type): Likewise.
	(enum nds32_isr_nested_type): Likewise.
	(enum reg_class): Likewise.
	* config/nds32/predicates.md: Likewise.
	* config/nds32/t-nds32: Likewise.
	* config/nios2/nios2.cc (nios2_pragma_target_parse): Likewise.
	* config/nvptx/nvptx-protos.h: Likewise.
	* config/nvptx/nvptx.cc (nvptx_goacc_expand_var_decl): Likewise.
	* config/nvptx/nvptx.h (TARGET_CPU_CPP_BUILTINS): Likewise.
	* config/nvptx/t-nvptx: Likewise.
	* config/nvptx/t-omp-device: Likewise.
	* config/pa/elf.h: Likewise.
	* config/pa/pa-linux.h (GLOBAL_ASM_OP): Likewise.
	* config/pa/pa-netbsd.h (GLOBAL_ASM_OP): Likewise.
	* config/pa/pa-openbsd.h (TARGET_ASM_GLOBALIZE_LABEL): Likewise.
	* config/pa/pa-protos.h (pa_eh_return_handler_rtx): Likewise.
	(pa_legitimize_reload_address): Likewise.
	(pa_can_use_return_insn): Likewise.
	* config/pa/pa.cc (mem_shadd_or_shadd_rtx_p): Likewise.
	(som_output_text_section_asm_op): Likewise.
	* config/pa/pa.h (PROFILE_BEFORE_PROLOGUE): Likewise.
	* config/pa/pa.md: Likewise.
	* config/pa/som.h: Likewise.
	* config/pa/t-pa: Likewise.
	* config/pdp11/pdp11.cc (decode_pdp11_d): Likewise.
	* config/pdp11/pdp11.h: Likewise.
	* config/pdp11/pdp11.md: Likewise.
	* config/pdp11/t-pdp11: Likewise.
	* config/pru/pru.md: Likewise.
	* config/pru/t-pru: Likewise.
	* config/riscv/riscv-protos.h (NUM_SYMBOL_TYPES): Likewise.
	(riscv_gpr_save_operation_p): Likewise.
	(riscv_d_register_target_info): Likewise.
	(riscv_init_builtins): Likewise.
	* config/riscv/riscv.cc (riscv_output_mi_thunk): Likewise.
	* config/riscv/riscv.h (CSW_MAX_OFFSET): Likewise.
	* config/riscv/t-riscv: Likewise.
	* config/rl78/rl78.cc (rl78_asm_ctor_dtor): Likewise.
	* config/rl78/t-rl78: Likewise.
	* config/rs6000/aix.h: Likewise.
	* config/rs6000/aix71.h (ASM_SPEC_COMMON): Likewise.
	* config/rs6000/aix72.h (ASM_SPEC_COMMON): Likewise.
	* config/rs6000/aix73.h (ASM_SPEC_COMMON): Likewise.
	* config/rs6000/darwin.h (TARGET_ASM_GLOBALIZE_LABEL): Likewise.
	* config/rs6000/driver-rs6000.cc: Likewise.
	* config/rs6000/freebsd.h: Likewise.
	* config/rs6000/freebsd64.h: Likewise.
	* config/rs6000/lynx.h (ASM_OUTPUT_ALIGN): Likewise.
	* config/rs6000/rbtree.cc: Likewise.
	* config/rs6000/rbtree.h: Likewise.
	* config/rs6000/rs6000-c.cc (rs6000_target_modify_macros): Likewise.
	* config/rs6000/rs6000-call.cc (rs6000_invalid_builtin): Likewise.
	(rs6000_expand_builtin): Likewise.
	(rs6000_init_builtins): Likewise.
	* config/rs6000/rs6000-cpus.def: Likewise.
	* config/rs6000/rs6000-gen-builtins.cc (write_init_ovld_table): Likewise.
	* config/rs6000/rs6000-internal.h (ALTIVEC_REG_BIT): Likewise.
	(quad_address_offset_p): Likewise.
	* config/rs6000/rs6000-logue.cc (interesting_frame_related_regno): Likewise.
	(rs6000_emit_epilogue): Likewise.
	* config/rs6000/rs6000-overload.def: Likewise.
	* config/rs6000/rs6000-p8swap.cc: Likewise.
	* config/rs6000/rs6000-protos.h (GCC_RS6000_PROTOS_H): Likewise.
	(rs6000_const_f32_to_i32): Likewise.
	* config/rs6000/rs6000.cc (legitimate_lo_sum_address_p): Likewise.
	(rs6000_debug_legitimize_address): Likewise.
	(rs6000_mode_dependent_address): Likewise.
	(rs6000_adjust_priority): Likewise.
	(rs6000_c_mode_for_suffix): Likewise.
	* config/rs6000/rs6000.h (defined): Likewise.
	(LONG_DOUBLE_TYPE_SIZE): Likewise.
	* config/rs6000/rs6000.md: Likewise.
	* config/rs6000/sysv4.h: Likewise.
	* config/rs6000/t-linux: Likewise.
	* config/rs6000/t-linux64: Likewise.
	* config/rs6000/t-rs6000: Likewise.
	* config/rs6000/x-darwin: Likewise.
	* config/rs6000/x-darwin64: Likewise.
	* config/rs6000/x-rs6000: Likewise.
	* config/rs6000/xcoff.h (ASM_OUTPUT_LABELREF): Likewise.
	* config/rx/rx.cc (rx_expand_builtin): Likewise.
	* config/s390/constraints.md: Likewise.
	* config/s390/driver-native.cc: Likewise.
	* config/s390/htmxlintrin.h: Likewise.
	* config/s390/s390-builtins.def (B_DEF): Likewise.
	(OB_DEF_VAR): Likewise.
	* config/s390/s390-builtins.h: Likewise.
	* config/s390/s390-c.cc: Likewise.
	* config/s390/s390-opts.h: Likewise.
	* config/s390/s390-protos.h (s390_check_symref_alignment): Likewise.
	(s390_register_target_pragmas): Likewise.
	* config/s390/s390.cc (s390_init_builtins): Likewise.
	(s390_expand_plus_operand): Likewise.
	(s390_expand_atomic): Likewise.
	(s390_valid_target_attribute_inner_p): Likewise.
	* config/s390/s390.h (LONG_DOUBLE_TYPE_SIZE): Likewise.
	* config/s390/s390.md: Likewise.
	* config/s390/t-s390: Likewise.
	* config/s390/vx-builtins.md: Likewise.
	* config/s390/x-native: Likewise.
	* config/sh/divtab-sh4-300.cc (main): Likewise.
	* config/sh/divtab-sh4.cc (main): Likewise.
	* config/sh/divtab.cc (main): Likewise.
	* config/sh/elf.h: Likewise.
	* config/sh/sh-protos.h (sh_fsca_int2sf): Likewise.
	* config/sh/sh.cc (SYMBOL_FLAG_FUNCVEC_FUNCTION): Likewise.
	(sh_struct_value_rtx): Likewise.
	(sh_remove_reg_dead_or_unused_notes): Likewise.
	* config/sh/sh.h (MIN_UNITS_PER_WORD): Likewise.
	* config/sh/t-sh: Likewise.
	* config/sol2-protos.h (solaris_override_options): Likewise.
	* config/sol2.h: Likewise.
	* config/sparc/driver-sparc.cc: Likewise.
	* config/sparc/freebsd.h: Likewise.
	* config/sparc/sparc-protos.h (make_pass_work_around_errata): Likewise.
	* config/sparc/sparc.cc (sparc_output_mi_thunk): Likewise.
	(sparc_asan_shadow_offset): Likewise.
	* config/sparc/sparc.h: Likewise.
	* config/sparc/sparc.md: Likewise.
	* config/sparc/t-sparc: Likewise.
	* config/sparc/x-sparc: Likewise.
	* config/stormy16/stormy16.cc (xstormy16_mode_dependent_address_p): Likewise.
	* config/t-darwin: Likewise.
	* config/t-dragonfly: Likewise.
	* config/t-freebsd: Likewise.
	* config/t-glibc: Likewise.
	* config/t-linux: Likewise.
	* config/t-netbsd: Likewise.
	* config/t-openbsd: Likewise.
	* config/t-pnt16-warn: Likewise.
	* config/t-sol2: Likewise.
	* config/t-vxworks: Likewise.
	* config/t-winnt: Likewise.
	* config/tilegx/t-tilegx: Likewise.
	* config/tilegx/tilegx-c.cc: Likewise.
	* config/tilegx/tilegx-protos.h (tilegx_function_profiler): Likewise.
	* config/tilegx/tilegx.md: Likewise.
	* config/tilepro/t-tilepro: Likewise.
	* config/tilepro/tilepro-c.cc: Likewise.
	* config/v850/t-v850: Likewise.
	* config/v850/v850-protos.h: Likewise.
	* config/v850/v850.cc (F): Likewise.
	* config/v850/v850.h (enum reg_class): Likewise.
	(SLOW_BYTE_ACCESS): Likewise.
	* config/vax/vax.cc (vax_mode_dependent_address_p): Likewise.
	* config/vax/vax.h (enum reg_class): Likewise.
	* config/vax/vax.md: Likewise.
	* config/visium/visium.cc (visium_legitimate_address_p): Likewise.
	* config/visium/visium.h: Likewise.
	* config/vms/t-vms: Likewise.
	* config/vms/vms-crtlmap.map: Likewise.
	* config/vms/vms-protos.h (vms_c_get_vms_ver): Likewise.
	* config/vx-common.h: Likewise.
	* config/x-darwin: Likewise.
	* config/x-hpux: Likewise.
	* config/x-linux: Likewise.
	* config/x-netbsd: Likewise.
	* config/x-openbsd: Likewise.
	* config/x-solaris: Likewise.
	* config/xtensa/xtensa-protos.h (xtensa_mem_offset): Likewise.
	* config/xtensa/xtensa.cc (xtensa_option_override): Likewise.
	* config/xtensa/xtensa.h: Likewise.
	* configure.ac: Likewise.
	* context.cc: Likewise.
	* convert.h: Likewise.
	* coretypes.h: Likewise.
	* coverage.cc: Likewise.
	* coverage.h: Likewise.
	* cppdefault.h (struct default_include): Likewise.
	* cprop.cc (local_cprop_pass): Likewise.
	(one_cprop_pass): Likewise.
	* cse.cc (hash_rtx_cb): Likewise.
	(fold_rtx): Likewise.
	* ctfc.h (ctfc_get_num_vlen_bytes): Likewise.
	* data-streamer.h (bp_unpack_var_len_int): Likewise.
	(streamer_write_widest_int): Likewise.
	* dbgcnt.def: Likewise.
	* dbxout.cc (dbxout_early_global_decl): Likewise.
	(dbxout_common_check): Likewise.
	* dbxout.h: Likewise.
	* debug.h (struct gcc_debug_hooks): Likewise.
	(dump_go_spec_init): Likewise.
	* df-core.cc: Likewise.
	* df-scan.cc (df_insn_info_delete): Likewise.
	(df_insn_delete): Likewise.
	* df.h (debug_df_chain): Likewise.
	(can_move_insns_across): Likewise.
	* dfp.cc (decimal_from_binary): Likewise.
	* diagnostic-color.cc: Likewise.
	* diagnostic-event-id.h: Likewise.
	* diagnostic-show-locus.cc (test_one_liner_labels): Likewise.
	* diagnostic.cc (bt_callback): Likewise.
	(num_digits): Likewise.
	* doc/avr-mmcu.texi: Likewise.
	* doc/cfg.texi: Likewise.
	* doc/contrib.texi: Likewise.
	* doc/cppinternals.texi: Likewise.
	* doc/extend.texi: Likewise.
	* doc/generic.texi: Likewise.
	* doc/gimple.texi: Likewise.
	* doc/gty.texi: Likewise.
	* doc/invoke.texi: Likewise.
	* doc/loop.texi: Likewise.
	* doc/lto.texi: Likewise.
	* doc/match-and-simplify.texi: Likewise.
	* doc/md.texi: Likewise.
	* doc/optinfo.texi: Likewise.
	* doc/options.texi: Likewise.
	* doc/passes.texi: Likewise.
	* doc/plugins.texi: Likewise.
	* doc/rtl.texi: Likewise.
	* doc/sourcebuild.texi: Likewise.
	* doc/tm.texi: Likewise.
	* doc/tm.texi.in: Likewise.
	* doc/tree-ssa.texi: Likewise.
	* dojump.cc (do_jump): Likewise.
	* dojump.h: Likewise.
	* dumpfile.cc (test_impl_location): Likewise.
	(test_capture_of_dump_calls): Likewise.
	* dumpfile.h (enum dump_kind): Likewise.
	(class dump_location_t): Likewise.
	(dump_enabled_p): Likewise.
	(enable_rtl_dump_file): Likewise.
	(dump_combine_total_stats): Likewise.
	* dwarf2asm.cc (dw2_asm_output_delta_uleb128): Likewise.
	* dwarf2ctf.h (ctf_debug_finish): Likewise.
	* dwarf2out.cc (dwarf2out_begin_prologue): Likewise.
	(struct loc_descr_context): Likewise.
	(rtl_for_decl_location): Likewise.
	(gen_subprogram_die): Likewise.
	(gen_label_die): Likewise.
	(is_trivial_indirect_ref): Likewise.
	(dwarf2out_late_global_decl): Likewise.
	(dwarf_file_hasher::hash): Likewise.
	(dwarf2out_end_source_file): Likewise.
	(dwarf2out_define): Likewise.
	(dwarf2out_early_finish): Likewise.
	* dwarf2out.h (struct dw_fde_node): Likewise.
	(struct dw_discr_list_node): Likewise.
	(output_loc_sequence_raw): Likewise.
	* emit-rtl.cc (gen_raw_REG): Likewise.
	(maybe_set_max_label_num): Likewise.
	* emit-rtl.h (struct rtl_data): Likewise.
	* errors.cc (internal_error): Likewise.
	(trim_filename): Likewise.
	* et-forest.cc: Likewise.
	* except.cc (init_eh_for_function): Likewise.
	* explow.cc (promote_ssa_mode): Likewise.
	(get_dynamic_stack_size): Likewise.
	* explow.h: Likewise.
	* expmed.h: Likewise.
	* expr.cc (safe_from_p): Likewise.
	(expand_expr_real_2): Likewise.
	(expand_expr_real_1): Likewise.
	* file-prefix-map.cc (remap_filename): Likewise.
	* final.cc (app_enable): Likewise.
	(make_pass_compute_alignments): Likewise.
	(final_scan_insn_1): Likewise.
	(final_scan_insn): Likewise.
	* fixed-value.h (fixed_from_string): Likewise.
	* flag-types.h (NO_DEBUG): Likewise.
	(DWARF2_DEBUG): Likewise.
	(VMS_DEBUG): Likewise.
	(BTF_DEBUG): Likewise.
	(enum ctf_debug_info_levels): Likewise.
	* fold-const.cc (const_binop): Likewise.
	(fold_binary_loc): Likewise.
	(fold_checksum_tree): Likewise.
	* fp-test.cc: Likewise.
	* function.cc (expand_function_end): Likewise.
	* function.h (struct function): Likewise.
	* fwprop.cc (should_replace_address): Likewise.
	* gcc-main.cc: Likewise.
	* gcc-rich-location.h (class gcc_rich_location): Likewise.
	* gcc-symtab.h: Likewise.
	* gcc.cc (MIN_FATAL_STATUS): Likewise.
	(driver_handle_option): Likewise.
	(quote_spec_arg): Likewise.
	(driver::finalize): Likewise.
	* gcc.h (set_input): Likewise.
	* gcov-dump.cc: Likewise.
	* gcov.cc (solve_flow_graph): Likewise.
	* gcse-common.cc: Likewise.
	* gcse.cc (make_pass_rtl_hoist): Likewise.
	* genattr-common.cc: Likewise.
	* genattrtab.cc (min_fn): Likewise.
	(write_const_num_delay_slots): Likewise.
	* genautomata.cc: Likewise.
	* genconditions.cc (write_one_condition): Likewise.
	* genconstants.cc: Likewise.
	* genemit.cc (gen_exp): Likewise.
	* generic-match-head.cc: Likewise.
	* genextract.cc: Likewise.
	* gengenrtl.cc (always_void_p): Likewise.
	* gengtype-parse.cc (gtymarker_opt): Likewise.
	* gengtype-state.cc (state_writer::state_writer): Likewise.
	(write_state_trailer): Likewise.
	(equals_type_number): Likewise.
	(read_state): Likewise.
	* gengtype.cc (open_base_files): Likewise.
	(struct file_rule_st): Likewise.
	(header_dot_h_frul): Likewise.
	* gengtype.h: Likewise.
	* genmatch.cc (main): Likewise.
	* genmddeps.cc: Likewise.
	* genmodes.cc (emit_mode_inner): Likewise.
	(emit_mode_unit_size): Likewise.
	* genpeep.cc (gen_peephole): Likewise.
	* genpreds.cc (write_tm_preds_h): Likewise.
	* genrecog.cc (validate_pattern): Likewise.
	(write_header): Likewise.
	(main): Likewise.
	* gensupport.cc (change_subst_attribute): Likewise.
	(traverse_c_tests): Likewise.
	(add_predicate): Likewise.
	(init_predicate_table): Likewise.
	* gensupport.h (struct optab_pattern): Likewise.
	(get_num_insn_codes): Likewise.
	(maybe_eval_c_test): Likewise.
	(struct pred_data): Likewise.
	* ggc-internal.h: Likewise.
	* gimple-fold.cc (maybe_fold_reference): Likewise.
	(get_range_strlen_tree): Likewise.
	* gimple-fold.h (gimple_stmt_integer_valued_real_p): Likewise.
	* gimple-low.cc: Likewise.
	* gimple-match-head.cc (directly_supported_p): Likewise.
	* gimple-pretty-print.h: Likewise.
	* gimple-ssa-sprintf.cc (format_percent): Likewise.
	(adjust_range_for_overflow): Likewise.
	* gimple-streamer.h: Likewise.
	* gimple.h (struct GTY): Likewise.
	(is_gimple_resx): Likewise.
	* gimplify.cc (gimplify_expr): Likewise.
	(gimplify_init_constructor): Likewise.
	(omp_construct_selector_matches): Likewise.
	(gimplify_omp_target_update): Likewise.
	(gimplify_omp_ordered): Likewise.
	(gimplify_va_arg_expr): Likewise.
	* graphite-isl-ast-to-gimple.cc (should_copy_to_new_region): Likewise.
	* haifa-sched.cc (increase_insn_priority): Likewise.
	(try_ready): Likewise.
	(sched_create_recovery_edges): Likewise.
	* ifcvt.cc (find_if_case_1): Likewise.
	(find_if_case_2): Likewise.
	* inchash.h: Likewise.
	* incpath.cc (add_env_var_paths): Likewise.
	* input.cc (dump_location_info): Likewise.
	(assert_loceq): Likewise.
	(test_lexer_string_locations_concatenation_1): Likewise.
	(test_lexer_string_locations_concatenation_2): Likewise.
	(test_lexer_string_locations_concatenation_3): Likewise.
	* input.h (BUILTINS_LOCATION): Likewise.
	(class string_concat_db): Likewise.
	* internal-fn.cc (expand_MUL_OVERFLOW): Likewise.
	(expand_LOOP_VECTORIZED): Likewise.
	* ipa-cp.cc (make_pass_ipa_cp): Likewise.
	* ipa-fnsummary.cc (remap_freqcounting_preds_after_dup): Likewise.
	(ipa_fn_summary_t::duplicate): Likewise.
	(make_pass_ipa_fn_summary): Likewise.
	* ipa-fnsummary.h (enum ipa_hints_vals): Likewise.
	* ipa-free-lang-data.cc (fld_simplified_type): Likewise.
	(free_lang_data_in_decl): Likewise.
	* ipa-inline.cc (compute_inlined_call_time): Likewise.
	(inline_always_inline_functions): Likewise.
	* ipa-inline.h (free_growth_caches): Likewise.
	(inline_account_function_p): Likewise.
	* ipa-modref.cc (modref_access_analysis::analyze_stmt): Likewise.
	(modref_eaf_analysis::analyze_ssa_name): Likewise.
	* ipa-param-manipulation.cc (ipa_param_body_adjustments::mark_dead_statements): Likewise.
	(ipa_param_body_adjustments::remap_with_debug_expressions): Likewise.
	* ipa-prop.cc (ipa_set_node_agg_value_chain): Likewise.
	* ipa-prop.h (IPA_UNDESCRIBED_USE): Likewise.
	(unadjusted_ptr_and_unit_offset): Likewise.
	* ipa-reference.cc (make_pass_ipa_reference): Likewise.
	* ipa-reference.h (GCC_IPA_REFERENCE_H): Likewise.
	* ipa-split.cc (consider_split): Likewise.
	* ipa-sra.cc (isra_read_node_info): Likewise.
	* ipa-utils.h (struct ipa_dfs_info): Likewise.
	(recursive_call_p): Likewise.
	(ipa_make_function_pure): Likewise.
	* ira-build.cc (ira_create_allocno): Likewise.
	(ira_flattening): Likewise.
	* ira-color.cc (do_coloring): Likewise.
	(update_curr_costs): Likewise.
	* ira-conflicts.cc (process_regs_for_copy): Likewise.
	* ira-int.h (struct ira_emit_data): Likewise.
	(ira_prohibited_mode_move_regs): Likewise.
	(ira_get_dup_out_num): Likewise.
	(ira_destroy): Likewise.
	(ira_tune_allocno_costs): Likewise.
	(ira_implicitly_set_insn_hard_regs): Likewise.
	(ira_build_conflicts): Likewise.
	(ira_color): Likewise.
	* ira-lives.cc (process_bb_node_lives): Likewise.
	* ira.cc (class ira_spilled_reg_stack_slot): Likewise.
	(setup_uniform_class_p): Likewise.
	(def_dominates_uses): Likewise.
	* ira.h (ira_nullify_asm_goto): Likewise.
	* langhooks.cc (lhd_post_options): Likewise.
	* langhooks.h (class substring_loc): Likewise.
	(struct lang_hooks_for_tree_inlining): Likewise.
	(struct lang_hooks_for_types): Likewise.
	(struct lang_hooks): Likewise.
	* libfuncs.h (synchronize_libfunc): Likewise.
	* loop-doloop.cc (doloop_condition_get): Likewise.
	* loop-init.cc (fix_loop_structure): Likewise.
	* loop-invariant.cc: Likewise.
	* lower-subreg.h: Likewise.
	* lra-constraints.cc (curr_insn_transform): Likewise.
	* lra-int.h (struct lra_insn_reg): Likewise.
	(lra_undo_inheritance): Likewise.
	(lra_setup_reload_pseudo_preferenced_hard_reg): Likewise.
	(lra_split_hard_reg_for): Likewise.
	(lra_coalesce): Likewise.
	(lra_final_code_change): Likewise.
	* lra-spills.cc (lra_final_code_change): Likewise.
	* lra.cc (lra_process_new_insns): Likewise.
	* lto-compress.h (struct lto_compression_stream): Likewise.
	* lto-streamer-out.cc (DFS::DFS_write_tree_body): Likewise.
	(write_symbol): Likewise.
	* lto-streamer.h (enum LTO_tags): Likewise.
	(lto_value_range_error): Likewise.
	(lto_append_block): Likewise.
	(lto_streamer_hooks_init): Likewise.
	(stream_read_tree_ref): Likewise.
	(lto_prepare_function_for_streaming): Likewise.
	(select_what_to_stream): Likewise.
	(omp_lto_input_declare_variant_alt): Likewise.
	(cl_optimization_stream_in): Likewise.
	* lto-wrapper.cc (append_compiler_options): Likewise.
	* machmode.def: Likewise.
	* machmode.h (struct int_n_data_t): Likewise.
	* main.cc (main): Likewise.
	* match.pd: Likewise.
	* omp-builtins.def (BUILT_IN_GOMP_CRITICAL_NAME_END): Likewise.
	(BUILT_IN_GOMP_LOOP_ULL_ORDERED_RUNTIME_NEXT): Likewise.
	* omp-expand.cc (expand_omp_atomic_fetch_op): Likewise.
	(make_pass_expand_omp_ssa): Likewise.
	* omp-low.cc (struct omp_context): Likewise.
	(struct omp_taskcopy_context): Likewise.
	(lower_omp): Likewise.
	* omp-oacc-neuter-broadcast.cc (omp_sese_active_worker_call): Likewise.
	(mask_name): Likewise.
	(omp_sese_dump_pars): Likewise.
	(worker_single_simple): Likewise.
	* omp-offload.cc (omp_finish_file): Likewise.
	(execute_oacc_loop_designation): Likewise.
	* optabs-query.cc (lshift_cheap_p): Likewise.
	* optc-gen.awk: Likewise.
	* optc-save-gen.awk: Likewise.
	* optinfo-emit-json.cc (optrecord_json_writer::optrecord_json_writer): Likewise.
	* opts-common.cc: Likewise.
	* output.h (app_enable): Likewise.
	(output_operand_lossage): Likewise.
	(insn_current_reference_address): Likewise.
	(get_insn_template): Likewise.
	(output_quoted_string): Likewise.
	* pass_manager.h (struct register_pass_info): Likewise.
	* plugin.cc: Likewise.
	* plugin.def (PLUGIN_ANALYZER_INIT): Likewise.
	* plugin.h (invoke_plugin_callbacks): Likewise.
	* pointer-query.cc (handle_mem_ref): Likewise.
	* postreload-gcse.cc (alloc_mem): Likewise.
	* predict.h (enum prediction): Likewise.
	(add_reg_br_prob_note): Likewise.
	* prefix.h: Likewise.
	* profile.h (get_working_sets): Likewise.
	* read-md.cc: Likewise.
	* read-md.h (struct mapping): Likewise.
	(class md_reader): Likewise.
	(class noop_reader): Likewise.
	* read-rtl-function.cc (function_reader::create_function): Likewise.
	(function_reader::extra_parsing_for_operand_code_0): Likewise.
	* read-rtl.cc (initialize_iterators): Likewise.
	* real.cc: Likewise.
	* real.h (struct real_value): Likewise.
	(format_helper::format_helper): Likewise.
	(real_hash): Likewise.
	(real_can_shorten_arithmetic): Likewise.
	* recog.cc (struct target_recog): Likewise.
	(offsettable_nonstrict_memref_p): Likewise.
	(constrain_operands): Likewise.
	* recog.h (MAX_RECOG_ALTERNATIVES): Likewise.
	(which_op_alt): Likewise.
	(struct insn_gen_fn): Likewise.
	* reg-notes.def (REG_NOTE): Likewise.
	* reg-stack.cc: Likewise.
	* regs.h (reg_is_parm_p): Likewise.
	* regset.h: Likewise.
	* reload.cc (push_reload): Likewise.
	(find_reloads): Likewise.
	(find_reloads_address_1): Likewise.
	(find_replacement): Likewise.
	(refers_to_regno_for_reload_p): Likewise.
	(refers_to_mem_for_reload_p): Likewise.
	* reload.h (push_reload): Likewise.
	(deallocate_reload_reg): Likewise.
	* reload1.cc (emit_input_reload_insns): Likewise.
	* reorg.cc (relax_delay_slots): Likewise.
	* rtl.def (UNKNOWN): Likewise.
	(SEQUENCE): Likewise.
	(BARRIER): Likewise.
	(ASM_OPERANDS): Likewise.
	(EQ_ATTR_ALT): Likewise.
	* rtl.h (struct GTY): Likewise.
	(LABEL_NAME): Likewise.
	(LABEL_ALT_ENTRY_P): Likewise.
	(SUBREG_BYTE): Likewise.
	(get_stack_check_protect): Likewise.
	(dump_rtx_statistics): Likewise.
	(unwrap_const_vec_duplicate): Likewise.
	(subreg_promoted_mode): Likewise.
	(gen_lowpart_common): Likewise.
	(operand_subword): Likewise.
	(immed_wide_int_const): Likewise.
	(decide_function_section): Likewise.
	(active_insn_p): Likewise.
	(delete_related_insns): Likewise.
	(try_split): Likewise.
	(val_signbit_known_clear_p): Likewise.
	(simplifiable_subregs): Likewise.
	(set_insn_deleted): Likewise.
	(subreg_get_info): Likewise.
	(remove_free_EXPR_LIST_node): Likewise.
	(finish_subregs_of_mode): Likewise.
	(get_mem_attrs): Likewise.
	(lookup_constant_def): Likewise.
	(rtx_to_tree_code): Likewise.
	(hash_rtx): Likewise.
	(condjump_in_parallel_p): Likewise.
	(validate_subreg): Likewise.
	(make_compound_operation): Likewise.
	(schedule_ebbs): Likewise.
	(print_inline_rtx): Likewise.
	(fixup_args_size_notes): Likewise.
	(expand_dec): Likewise.
	(prepare_copy_insn): Likewise.
	(mark_elimination): Likewise.
	(valid_mode_changes_for_regno): Likewise.
	(make_debug_expr_from_rtl): Likewise.
	(delete_vta_debug_insns): Likewise.
	(simplify_using_condition): Likewise.
	(set_insn_locations): Likewise.
	(fatal_insn_not_found): Likewise.
	(word_register_operation_p): Likewise.
	* rtlanal.cc (get_call_fndecl): Likewise.
	(side_effects_p): Likewise.
	(subreg_nregs): Likewise.
	(rtx_cost): Likewise.
	(canonicalize_condition): Likewise.
	* rtlanal.h (rtx_properties::try_to_add_note): Likewise.
	* run-rtl-passes.cc (run_rtl_passes): Likewise.
	* sanitizer.def (BUILT_IN_ASAN_VERSION_MISMATCH_CHECK): Likewise.
	* sched-deps.cc (add_dependence_1): Likewise.
	* sched-ebb.cc (begin_move_insn): Likewise.
	(add_deps_for_risky_insns): Likewise.
	(advance_target_bb): Likewise.
	* sched-int.h (reemit_notes): Likewise.
	(struct _haifa_insn_data): Likewise.
	(HID): Likewise.
	(DEP_CANCELLED): Likewise.
	(debug_ds): Likewise.
	(number_in_ready): Likewise.
	(schedule_ebbs_finish): Likewise.
	(find_modifiable_mems): Likewise.
	* sched-rgn.cc (debug_rgn_dependencies): Likewise.
	* sel-sched-dump.cc (dump_lv_set): Likewise.
	* sel-sched-dump.h: Likewise.
	* sel-sched-ir.cc (sel_insn_rtx_cost): Likewise.
	(setup_id_reg_sets): Likewise.
	(has_dependence_p): Likewise.
	(sel_num_cfg_preds_gt_1): Likewise.
	(bb_ends_ebb_p): Likewise.
	* sel-sched-ir.h (struct _list_node): Likewise.
	(struct idata_def): Likewise.
	(bb_next_bb): Likewise.
	* sel-sched.cc (vinsn_writes_one_of_regs_p): Likewise.
	(choose_best_pseudo_reg): Likewise.
	(verify_target_availability): Likewise.
	(can_speculate_dep_p): Likewise.
	(sel_rank_for_schedule): Likewise.
	* selftest-run-tests.cc (selftest::run_tests): Likewise.
	* selftest.h (class auto_fix_quotes): Likewise.
	* shrink-wrap.cc (handle_simple_exit): Likewise.
	* shrink-wrap.h: Likewise.
	* simplify-rtx.cc (simplify_context::simplify_associative_operation): Likewise.
	(simplify_context::simplify_gen_vec_select): Likewise.
	* spellcheck-tree.h: Likewise.
	* spellcheck.h: Likewise.
	* statistics.h (struct function): Likewise.
	* stmt.cc (conditional_probability): Likewise.
	* stmt.h: Likewise.
	* stor-layout.h: Likewise.
	* streamer-hooks.h: Likewise.
	* stringpool.h: Likewise.
	* symtab.cc (symbol_table::change_decl_assembler_name): Likewise.
	* target.def (HOOK_VECTOR_END): Likewise.
	(type.): Likewise.
	* target.h (union cumulative_args_t): Likewise.
	(by_pieces_ninsns): Likewise.
	(class predefined_function_abi): Likewise.
	* targhooks.cc (default_translate_mode_attribute): Likewise.
	* timevar.def: Likewise.
	* timevar.h (class timer): Likewise.
	* toplev.h (enable_rtl_dump_file): Likewise.
	* trans-mem.cc (collect_bb2reg): Likewise.
	* tree-call-cdce.cc (gen_conditions_for_pow): Likewise.
	* tree-cfg.cc (remove_bb): Likewise.
	(verify_gimple_debug): Likewise.
	(remove_edge_and_dominated_blocks): Likewise.
	(push_fndecl): Likewise.
	* tree-cfgcleanup.h (GCC_TREE_CFGCLEANUP_H): Likewise.
	* tree-complex.cc (expand_complex_multiplication): Likewise.
	(expand_complex_div_straight): Likewise.
	* tree-core.h (enum tree_index): Likewise.
	(enum operand_equal_flag): Likewise.
	* tree-eh.cc (honor_protect_cleanup_actions): Likewise.
	* tree-if-conv.cc (if_convertible_gimple_assign_stmt_p): Likewise.
	* tree-inline.cc (initialize_inlined_parameters): Likewise.
	* tree-inline.h (force_value_to_type): Likewise.
	* tree-nested.cc (get_chain_decl): Likewise.
	(walk_all_functions): Likewise.
	* tree-object-size.h: Likewise.
	* tree-outof-ssa.cc: Likewise.
	* tree-parloops.cc (create_parallel_loop): Likewise.
	* tree-pretty-print.cc (print_generic_expr_to_str): Likewise.
	(dump_generic_node): Likewise.
	* tree-profile.cc (tree_profiling): Likewise.
	* tree-sra.cc (maybe_add_sra_candidate): Likewise.
	* tree-ssa-address.cc: Likewise.
	* tree-ssa-alias.cc: Likewise.
	* tree-ssa-alias.h (ao_ref::max_size_known_p): Likewise.
	(dump_alias_stats): Likewise.
	* tree-ssa-ccp.cc: Likewise.
	* tree-ssa-coalesce.h: Likewise.
	* tree-ssa-live.cc (remove_unused_scope_block_p): Likewise.
	* tree-ssa-loop-manip.cc (copy_phi_node_args): Likewise.
	* tree-ssa-loop-unswitch.cc: Likewise.
	* tree-ssa-math-opts.cc: Likewise.
	* tree-ssa-operands.cc (class operands_scanner): Likewise.
	* tree-ssa-pre.cc: Likewise.
	* tree-ssa-reassoc.cc (optimize_ops_list): Likewise.
	(debug_range_entry): Likewise.
	* tree-ssa-sccvn.cc (eliminate_dom_walker::eliminate_stmt): Likewise.
	* tree-ssa-sccvn.h (TREE_SSA_SCCVN_H): Likewise.
	* tree-ssa-scopedtables.cc (add_expr_commutative): Likewise.
	(equal_mem_array_ref_p): Likewise.
	* tree-ssa-strlen.cc (is_strlen_related_p): Likewise.
	* tree-ssa-strlen.h (get_range_strlen_dynamic): Likewise.
	* tree-ssa-tail-merge.cc (stmt_local_def): Likewise.
	* tree-ssa-ter.h: Likewise.
	* tree-ssa-threadupdate.h (enum bb_dom_status): Likewise.
	* tree-streamer-in.cc (lto_input_ts_block_tree_pointers): Likewise.
	* tree-streamer-out.cc (pack_ts_block_value_fields): Likewise.
	(write_ts_block_tree_pointers): Likewise.
	* tree-streamer.h (struct streamer_tree_cache_d): Likewise.
	(streamer_read_tree_bitfields): Likewise.
	(streamer_write_integer_cst): Likewise.
	* tree-vect-patterns.cc (apply_binop_and_append_stmt): Likewise.
	(vect_synth_mult_by_constant): Likewise.
	* tree-vect-stmts.cc (vectorizable_operation): Likewise.
	* tree-vectorizer.cc: Likewise.
	* tree-vectorizer.h (class auto_purge_vect_location): Likewise.
	(vect_update_inits_of_drs): Likewise.
	(vect_get_mask_type_for_stmt): Likewise.
	(vect_rgroup_iv_might_wrap_p): Likewise.
	(cse_and_gimplify_to_preheader): Likewise.
	(vect_free_slp_tree): Likewise.
	(vect_pattern_recog): Likewise.
	(vect_stmt_dominates_stmt_p): Likewise.
	* tree.cc (initialize_tree_contains_struct): Likewise.
	(need_assembler_name_p): Likewise.
	(type_with_interoperable_signedness): Likewise.
	* tree.def (SWITCH_EXPR): Likewise.
	* tree.h (TYPE_SYMTAB_ADDRESS): Likewise.
	(poly_int_tree_p): Likewise.
	(inlined_function_outer_scope_p): Likewise.
	(tree_code_for_canonical_type_merging): Likewise.
	* value-prof.cc: Likewise.
	* value-prof.h (get_nth_most_common_value): Likewise.
	(find_func_by_profile_id): Likewise.
	* value-range.cc (vrp_operand_equal_p): Likewise.
	* value-range.h: Likewise.
	* var-tracking.cc: Likewise.
	* varasm.cc (default_function_section): Likewise.
	(function_section_1): Likewise.
	(assemble_variable): Likewise.
	(handle_vtv_comdat_section): Likewise.
	* vec.h (struct vec_prefix): Likewise.
	* vmsdbgout.cc (full_name): Likewise.
	* vtable-verify.cc: Likewise.
	* vtable-verify.h (struct vtv_graph_node): Likewise.
	* xcoffout.cc: Likewise.
	* xcoffout.h (DEBUG_SYMS_TEXT): Likewise.

gcc/ada/ChangeLog:

	* Make-generated.in: Rename .c names to .cc.
	* adaint.c: Likewise.
	* ctrl_c.c (dummy_handler): Likewise.
	* gcc-interface/Makefile.in: Likewise.
	* gcc-interface/config-lang.in: Likewise.
	* gcc-interface/decl.cc (concat_name): Likewise.
	(init_gnat_decl): Likewise.
	* gcc-interface/gigi.h (concat_name): Likewise.
	(init_gnat_utils): Likewise.
	(build_call_raise_range): Likewise.
	(gnat_mark_addressable): Likewise.
	(gnat_protect_expr): Likewise.
	(gnat_rewrite_reference): Likewise.
	* gcc-interface/lang-specs.h (ADA_DUMPS_OPTIONS): Likewise.
	* gcc-interface/utils.cc (GTY): Likewise.
	(add_deferred_type_context): Likewise.
	(init_gnat_utils): Likewise.
	* gcc-interface/utils2.cc (gnat_stable_expr_p): Likewise.
	(gnat_protect_expr): Likewise.
	(gnat_stabilize_reference_1): Likewise.
	(gnat_rewrite_reference): Likewise.
	* gsocket.h: Likewise.
	* init.cc (__gnat_error_handler): Likewise.
	* libgnarl/s-intman.ads: Likewise.
	* libgnarl/s-osinte__android.ads: Likewise.
	* libgnarl/s-osinte__darwin.ads: Likewise.
	* libgnarl/s-osinte__hpux.ads: Likewise.
	* libgnarl/s-osinte__linux.ads: Likewise.
	* libgnarl/s-osinte__qnx.ads: Likewise.
	* libgnarl/s-taskin.ads: Likewise.
	* rtfinal.cc: Likewise.
	* s-oscons-tmplt.c (CND): Likewise.
	* set_targ.ads: Likewise.

gcc/analyzer/ChangeLog:

	* analyzer.cc (is_special_named_call_p): Rename .c names to .cc.
	(is_named_call_p): Likewise.
	* region-model-asm.cc (deterministic_p): Likewise.
	* region.cc (field_region::get_relative_concrete_offset): Likewise.
	* sm-malloc.cc (method_p): Likewise.
	* supergraph.cc (superedge::dump_dot): Likewise.

gcc/c-family/ChangeLog:

	* c-ada-spec.cc: Rename .c names to .cc.
	* c-ada-spec.h: Likewise.
	* c-common.cc (c_build_vec_convert): Likewise.
	(warning_candidate_p): Likewise.
	* c-common.h (enum rid): Likewise.
	(build_real_imag_expr): Likewise.
	(finish_label_address_expr): Likewise.
	(c_get_substring_location): Likewise.
	(c_build_bind_expr): Likewise.
	(conflict_marker_get_final_tok_kind): Likewise.
	(c_parse_error): Likewise.
	(check_missing_format_attribute): Likewise.
	(invalid_array_size_error): Likewise.
	(warn_for_multistatement_macros): Likewise.
	(build_attr_access_from_parms): Likewise.
	* c-cppbuiltin.cc (c_cpp_builtins): Likewise.
	* c-format.cc: Likewise.
	* c-gimplify.cc (c_gimplify_expr): Likewise.
	* c-indentation.h: Likewise.
	* c-objc.h (objc_prop_attr_kind_for_rid): Likewise.
	* c-omp.cc (c_omp_predetermined_mapping): Likewise.
	* c-opts.cc (c_common_post_options): Likewise.
	(set_std_cxx23): Likewise.
	* c-pragma.cc (handle_pragma_redefine_extname): Likewise.
	* c-pretty-print.h: Likewise.

gcc/c/ChangeLog:

	* Make-lang.in: Rename .c names to .cc.
	* c-convert.cc: Likewise.
	* c-decl.cc (struct lang_identifier): Likewise.
	(pop_scope): Likewise.
	(finish_decl): Likewise.
	* c-objc-common.h (GCC_C_OBJC_COMMON): Likewise.
	* c-parser.cc (c_parser_skip_to_end_of_block_or_statement): Likewise.
	* c-parser.h (GCC_C_PARSER_H): Likewise.
	* c-tree.h (c_keyword_starts_typename): Likewise.
	(finish_declspecs): Likewise.
	(c_get_alias_set): Likewise.
	(enum c_oracle_request): Likewise.
	(tag_exists_p): Likewise.
	(set_c_expr_source_range): Likewise.
	* c-typeck.cc (c_common_type): Likewise.
	(c_finish_omp_clauses): Likewise.
	* config-lang.in: Likewise.

gcc/cp/ChangeLog:

	* Make-lang.in: Rename .c names to .cc.
	* config-lang.in: Likewise.
	* constexpr.cc (cxx_eval_constant_expression): Likewise.
	* coroutines.cc (morph_fn_to_coro): Likewise.
	* cp-gimplify.cc (cp_gimplify_expr): Likewise.
	* cp-lang.cc (struct lang_hooks): Likewise.
	(get_template_argument_pack_elems_folded): Likewise.
	* cp-objcp-common.cc (cp_tree_size): Likewise.
	(cp_unit_size_without_reusable_padding): Likewise.
	(pop_file_scope): Likewise.
	(cp_pushdecl): Likewise.
	* cp-objcp-common.h (GCC_CP_OBJCP_COMMON): Likewise.
	(cxx_simulate_record_decl): Likewise.
	* cp-tree.h (struct named_label_entry): Likewise.
	(current_function_return_value): Likewise.
	(more_aggr_init_expr_args_p): Likewise.
	(get_function_version_dispatcher): Likewise.
	(common_enclosing_class): Likewise.
	(strip_fnptr_conv): Likewise.
	(current_decl_namespace): Likewise.
	(do_aggregate_paren_init): Likewise.
	(cp_check_const_attributes): Likewise.
	(qualified_name_lookup_error): Likewise.
	(generic_targs_for): Likewise.
	(mark_exp_read): Likewise.
	(is_global_friend): Likewise.
	(maybe_reject_flexarray_init): Likewise.
	(module_token_lang): Likewise.
	(handle_module_option): Likewise.
	(literal_integer_zerop): Likewise.
	(build_extra_args): Likewise.
	(build_if_nonnull): Likewise.
	(maybe_check_overriding_exception_spec): Likewise.
	(finish_omp_target_clauses): Likewise.
	(maybe_warn_zero_as_null_pointer_constant): Likewise.
	(cxx_print_error_function): Likewise.
	(decl_in_std_namespace_p): Likewise.
	(merge_exception_specifiers): Likewise.
	(mangle_module_global_init): Likewise.
	(cxx_block_may_fallthru): Likewise.
	(fold_builtin_source_location): Likewise.
	(enum cp_oracle_request): Likewise.
	(subsumes): Likewise.
	(cp_finish_injected_record_type): Likewise.
	(vtv_build_vtable_verify_fndecl): Likewise.
	(cp_tree_c_finish_parsing): Likewise.
	* cvt.cc (diagnose_ref_binding): Likewise.
	(convert_to_void): Likewise.
	(convert_force): Likewise.
	(type_promotes_to): Likewise.
	* decl.cc (make_unbound_class_template_raw): Likewise.
	(cxx_init_decl_processing): Likewise.
	(check_class_member_definition_namespace): Likewise.
	(cxx_maybe_build_cleanup): Likewise.
	* decl2.cc (maybe_emit_vtables): Likewise.
	* error.cc (dump_function_name): Likewise.
	* init.cc (is_class_type): Likewise.
	(build_new_1): Likewise.
	* lang-specs.h: Likewise.
	* method.cc (make_alias_for_thunk): Likewise.
	* module.cc (specialization_add): Likewise.
	(module_state::read_cluster): Likewise.
	* name-lookup.cc (check_extern_c_conflict): Likewise.
	* name-lookup.h (struct cxx_binding): Likewise.
	* parser.cc (cp_parser_identifier): Likewise.
	* parser.h (struct cp_parser): Likewise.
	* pt.cc (has_value_dependent_address): Likewise.
	(push_tinst_level_loc): Likewise.
	* semantics.cc (finish_omp_clauses): Likewise.
	(finish_omp_atomic): Likewise.
	* tree.cc (cp_save_expr): Likewise.
	(cp_free_lang_data): Likewise.
	* typeck.cc (cp_common_type): Likewise.
	(strip_array_domain): Likewise.
	(rationalize_conditional_expr): Likewise.
	(check_return_expr): Likewise.
	* vtable-class-hierarchy.cc: Likewise.

gcc/d/ChangeLog:

	* d-gimplify.cc: Rename .c names to .cc.
	* d-incpath.cc: Likewise.
	* lang-specs.h: Likewise.

gcc/fortran/ChangeLog:

	* check.cc (gfc_check_all_any): Rename .c names to .cc.
	* class.cc (find_intrinsic_vtab): Likewise.
	* config-lang.in: Likewise.
	* cpp.cc (cpp_define_builtins): Likewise.
	* data.cc (get_array_index): Likewise.
	* decl.cc (match_clist_expr): Likewise.
	(get_proc_name): Likewise.
	(gfc_verify_c_interop_param): Likewise.
	(gfc_get_pdt_instance): Likewise.
	(gfc_match_formal_arglist): Likewise.
	(gfc_get_type_attr_spec): Likewise.
	* dependency.cc: Likewise.
	* error.cc (gfc_format_decoder): Likewise.
	* expr.cc (check_restricted): Likewise.
	(gfc_build_default_init_expr): Likewise.
	* f95-lang.cc: Likewise.
	* gfc-internals.texi: Likewise.
	* gfortran.h (enum match): Likewise.
	(enum procedure_type): Likewise.
	(enum oacc_routine_lop): Likewise.
	(gfc_get_pdt_instance): Likewise.
	(gfc_end_source_files): Likewise.
	(gfc_mpz_set_hwi): Likewise.
	(gfc_get_option_string): Likewise.
	(gfc_find_sym_in_expr): Likewise.
	(gfc_errors_to_warnings): Likewise.
	(gfc_real_4_kind): Likewise.
	(gfc_free_finalizer): Likewise.
	(gfc_sym_get_dummy_args): Likewise.
	(gfc_check_intrinsic_standard): Likewise.
	(gfc_free_case_list): Likewise.
	(gfc_resolve_oacc_routines): Likewise.
	(gfc_check_vardef_context): Likewise.
	(gfc_free_association_list): Likewise.
	(gfc_implicit_pure_function): Likewise.
	(gfc_ref_dimen_size): Likewise.
	(gfc_compare_actual_formal): Likewise.
	(gfc_resolve_wait): Likewise.
	(gfc_dt_upper_string): Likewise.
	(gfc_generate_module_code): Likewise.
	(gfc_delete_bbt): Likewise.
	(debug): Likewise.
	(gfc_build_block_ns): Likewise.
	(gfc_dep_difference): Likewise.
	(gfc_invalid_null_arg): Likewise.
	(gfc_is_finalizable): Likewise.
	(gfc_fix_implicit_pure): Likewise.
	(gfc_is_size_zero_array): Likewise.
	(gfc_is_reallocatable_lhs): Likewise.
	* gfortranspec.cc: Likewise.
	* interface.cc (compare_actual_expr): Likewise.
	* intrinsic.cc (add_functions): Likewise.
	* iresolve.cc (gfc_resolve_matmul): Likewise.
	(gfc_resolve_alarm_sub): Likewise.
	* iso-c-binding.def: Likewise.
	* lang-specs.h: Likewise.
	* libgfortran.h (GFC_STDERR_UNIT_NUMBER): Likewise.
	* match.cc (gfc_match_label): Likewise.
	(gfc_match_symbol): Likewise.
	(match_derived_type_spec): Likewise.
	(copy_ts_from_selector_to_associate): Likewise.
	* match.h (gfc_match_call): Likewise.
	(gfc_get_common): Likewise.
	(gfc_match_omp_end_single): Likewise.
	(gfc_match_volatile): Likewise.
	(gfc_match_bind_c): Likewise.
	(gfc_match_literal_constant): Likewise.
	(gfc_match_init_expr): Likewise.
	(gfc_match_array_constructor): Likewise.
	(gfc_match_end_interface): Likewise.
	(gfc_match_print): Likewise.
	(gfc_match_expr): Likewise.
	* matchexp.cc (next_operator): Likewise.
	* mathbuiltins.def: Likewise.
	* module.cc (free_true_name): Likewise.
	* openmp.cc (gfc_resolve_omp_parallel_blocks): Likewise.
	(gfc_omp_save_and_clear_state): Likewise.
	* parse.cc (parse_union): Likewise.
	(set_syms_host_assoc): Likewise.
	* resolve.cc (resolve_actual_arglist): Likewise.
	(resolve_elemental_actual): Likewise.
	(check_host_association): Likewise.
	(resolve_typebound_function): Likewise.
	(resolve_typebound_subroutine): Likewise.
	(gfc_resolve_expr): Likewise.
	(resolve_assoc_var): Likewise.
	(resolve_typebound_procedures): Likewise.
	(resolve_equivalence_derived): Likewise.
	* simplify.cc (simplify_bound): Likewise.
	* symbol.cc (gfc_set_default_type): Likewise.
	(gfc_add_ext_attribute): Likewise.
	* target-memory.cc (gfc_target_interpret_expr): Likewise.
	* target-memory.h (gfc_target_interpret_expr): Likewise.
	* trans-array.cc (gfc_get_cfi_dim_sm): Likewise.
	(gfc_conv_shift_descriptor_lbound): Likewise.
	(gfc_could_be_alias): Likewise.
	(gfc_get_dataptr_offset): Likewise.
	* trans-const.cc: Likewise.
	* trans-decl.cc (trans_function_start): Likewise.
	(gfc_trans_deferred_vars): Likewise.
	(generate_local_decl): Likewise.
	(gfc_generate_function_code): Likewise.
	* trans-expr.cc (gfc_vptr_size_get): Likewise.
	(gfc_trans_class_array_init_assign): Likewise.
	(POWI_TABLE_SIZE): Likewise.
	(gfc_conv_procedure_call): Likewise.
	(gfc_trans_arrayfunc_assign): Likewise.
	* trans-intrinsic.cc (gfc_conv_intrinsic_len): Likewise.
	(gfc_conv_intrinsic_loc): Likewise.
	(conv_intrinsic_event_query): Likewise.
	* trans-io.cc (gfc_build_st_parameter): Likewise.
	* trans-openmp.cc (gfc_omp_check_optional_argument): Likewise.
	(gfc_omp_unshare_expr_r): Likewise.
	(gfc_trans_omp_array_section): Likewise.
	(gfc_trans_omp_clauses): Likewise.
	* trans-stmt.cc (trans_associate_var): Likewise.
	(gfc_trans_deallocate): Likewise.
	* trans-stmt.h (gfc_trans_class_init_assign): Likewise.
	(gfc_trans_deallocate): Likewise.
	(gfc_trans_oacc_declare): Likewise.
	* trans-types.cc: Likewise.
	* trans-types.h (enum gfc_packed): Likewise.
	* trans.cc (N_): Likewise.
	(trans_code): Likewise.
	* trans.h (gfc_build_compare_string): Likewise.
	(gfc_conv_expr_type): Likewise.
	(gfc_trans_deferred_vars): Likewise.
	(getdecls): Likewise.
	(gfc_get_array_descr_info): Likewise.
	(gfc_omp_firstprivatize_type_sizes): Likewise.
	(GTY): Likewise.

gcc/go/ChangeLog:

	* config-lang.in: Rename .c names to .cc.
	* go-backend.cc: Likewise.
	* go-lang.cc: Likewise.
	* gospec.cc: Likewise.
	* lang-specs.h: Likewise.

gcc/jit/ChangeLog:

	* config-lang.in: Rename .c names to .cc.
	* docs/_build/texinfo/libgccjit.texi: Likewise.
	* docs/internals/index.rst: Likewise.
	* jit-builtins.cc (builtins_manager::make_builtin_function): Likewise.
	* jit-playback.cc (fold_const_var): Likewise.
	(playback::context::~context): Likewise.
	(new_field): Likewise.
	(new_bitfield): Likewise.
	(new_compound_type): Likewise.
	(playback::compound_type::set_fields): Likewise.
	(global_set_init_rvalue): Likewise.
	(load_blob_in_ctor): Likewise.
	(new_global_initialized): Likewise.
	(double>): Likewise.
	(new_string_literal): Likewise.
	(as_truth_value): Likewise.
	(build_call): Likewise.
	(playback::context::build_cast): Likewise.
	(new_array_access): Likewise.
	(new_field_access): Likewise.
	(dereference): Likewise.
	(postprocess): Likewise.
	(add_jump): Likewise.
	(add_switch): Likewise.
	(build_goto_operands): Likewise.
	(playback::context::read_dump_file): Likewise.
	(init_types): Likewise.
	* jit-recording.cc (recording::context::get_int_type): Likewise.
	* jit-recording.h: Likewise.
	* libgccjit.cc (compatible_types): Likewise.
	(gcc_jit_context_acquire): Likewise.
	(gcc_jit_context_release): Likewise.
	(gcc_jit_context_new_child_context): Likewise.
	(gcc_jit_type_as_object): Likewise.
	(gcc_jit_context_get_type): Likewise.
	(gcc_jit_context_get_int_type): Likewise.
	(gcc_jit_type_get_pointer): Likewise.
	(gcc_jit_type_get_const): Likewise.
	(gcc_jit_type_get_volatile): Likewise.
	(gcc_jit_type_dyncast_array): Likewise.
	(gcc_jit_type_is_bool): Likewise.
	(gcc_jit_type_is_pointer): Likewise.
	(gcc_jit_type_is_integral): Likewise.
	(gcc_jit_type_dyncast_vector): Likewise.
	(gcc_jit_type_is_struct): Likewise.
	(gcc_jit_vector_type_get_num_units): Likewise.
	(gcc_jit_vector_type_get_element_type): Likewise.
	(gcc_jit_type_unqualified): Likewise.
	(gcc_jit_type_dyncast_function_ptr_type): Likewise.
	(gcc_jit_function_type_get_return_type): Likewise.
	(gcc_jit_function_type_get_param_count): Likewise.
	(gcc_jit_function_type_get_param_type): Likewise.
	(gcc_jit_context_new_array_type): Likewise.
	(gcc_jit_context_new_field): Likewise.
	(gcc_jit_field_as_object): Likewise.
	(gcc_jit_context_new_struct_type): Likewise.
	(gcc_jit_struct_as_type): Likewise.
	(gcc_jit_struct_set_fields): Likewise.
	(gcc_jit_struct_get_field_count): Likewise.
	(gcc_jit_context_new_union_type): Likewise.
	(gcc_jit_context_new_function_ptr_type): Likewise.
	(gcc_jit_param_as_rvalue): Likewise.
	(gcc_jit_context_new_function): Likewise.
	(gcc_jit_function_get_return_type): Likewise.
	(gcc_jit_function_dump_to_dot): Likewise.
	(gcc_jit_block_get_function): Likewise.
	(gcc_jit_global_set_initializer_rvalue): Likewise.
	(gcc_jit_rvalue_get_type): Likewise.
	(gcc_jit_context_new_rvalue_from_int): Likewise.
	(gcc_jit_context_one): Likewise.
	(gcc_jit_context_new_rvalue_from_double): Likewise.
	(gcc_jit_context_null): Likewise.
	(gcc_jit_context_new_string_literal): Likewise.
	(valid_binary_op_p): Likewise.
	(gcc_jit_context_new_binary_op): Likewise.
	(gcc_jit_context_new_comparison): Likewise.
	(gcc_jit_context_new_call): Likewise.
	(is_valid_cast): Likewise.
	(gcc_jit_context_new_cast): Likewise.
	(gcc_jit_object_get_context): Likewise.
	(gcc_jit_object_get_debug_string): Likewise.
	(gcc_jit_lvalue_access_field): Likewise.
	(gcc_jit_rvalue_access_field): Likewise.
	(gcc_jit_rvalue_dereference_field): Likewise.
	(gcc_jit_rvalue_dereference): Likewise.
	(gcc_jit_lvalue_get_address): Likewise.
	(gcc_jit_lvalue_set_tls_model): Likewise.
	(gcc_jit_lvalue_set_link_section): Likewise.
	(gcc_jit_function_new_local): Likewise.
	(gcc_jit_block_add_eval): Likewise.
	(gcc_jit_block_add_assignment): Likewise.
	(is_bool): Likewise.
	(gcc_jit_block_end_with_conditional): Likewise.
	(gcc_jit_block_add_comment): Likewise.
	(gcc_jit_block_end_with_jump): Likewise.
	(gcc_jit_block_end_with_return): Likewise.
	(gcc_jit_block_end_with_void_return): Likewise.
	(case_range_validator::case_range_validator): Likewise.
	(case_range_validator::validate): Likewise.
	(case_range_validator::get_wide_int): Likewise.
	(gcc_jit_block_end_with_switch): Likewise.
	(gcc_jit_context_set_str_option): Likewise.
	(gcc_jit_context_set_int_option): Likewise.
	(gcc_jit_context_set_bool_option): Likewise.
	(gcc_jit_context_set_bool_allow_unreachable_blocks): Likewise.
	(gcc_jit_context_set_bool_use_external_driver): Likewise.
	(gcc_jit_context_add_command_line_option): Likewise.
	(gcc_jit_context_add_driver_option): Likewise.
	(gcc_jit_context_enable_dump): Likewise.
	(gcc_jit_context_compile): Likewise.
	(gcc_jit_context_compile_to_file): Likewise.
	(gcc_jit_context_set_logfile): Likewise.
	(gcc_jit_context_dump_reproducer_to_file): Likewise.
	(gcc_jit_context_get_first_error): Likewise.
	(gcc_jit_context_get_last_error): Likewise.
	(gcc_jit_result_get_code): Likewise.
	(gcc_jit_result_get_global): Likewise.
	(gcc_jit_rvalue_set_bool_require_tail_call): Likewise.
	(gcc_jit_type_get_aligned): Likewise.
	(gcc_jit_type_get_vector): Likewise.
	(gcc_jit_function_get_address): Likewise.
	(gcc_jit_version_patchlevel): Likewise.
	(gcc_jit_block_add_extended_asm): Likewise.
	(gcc_jit_extended_asm_as_object): Likewise.
	(gcc_jit_extended_asm_set_volatile_flag): Likewise.
	(gcc_jit_extended_asm_set_inline_flag): Likewise.
	(gcc_jit_extended_asm_add_output_operand): Likewise.
	(gcc_jit_extended_asm_add_input_operand): Likewise.
	(gcc_jit_extended_asm_add_clobber): Likewise.
	* notes.txt: Likewise.

gcc/lto/ChangeLog:

	* config-lang.in: Rename .c names to .cc.
	* lang-specs.h: Likewise.
	* lto-common.cc (gimple_register_canonical_type_1): Likewise.
	* lto-common.h: Likewise.
	* lto-dump.cc (lto_main): Likewise.
	* lto-lang.cc (handle_fnspec_attribute): Likewise.
	(lto_getdecls): Likewise.
	(lto_init): Likewise.
	* lto.cc (lto_main): Likewise.
	* lto.h: Likewise.

gcc/objc/ChangeLog:

	* Make-lang.in: Rename .c names to .cc.
	* config-lang.in: Likewise.
	* lang-specs.h: Likewise.
	* objc-act.cc (objc_build_component_ref): Likewise.
	(objc_copy_binfo): Likewise.
	(lookup_method_in_hash_lists): Likewise.
	(objc_finish_foreach_loop): Likewise.
	* objc-act.h (objc_common_init_ts): Likewise.
	* objc-gnu-runtime-abi-01.cc: Likewise.
	* objc-lang.cc (struct lang_hooks): Likewise.
	* objc-map.cc: Likewise.
	* objc-next-runtime-abi-01.cc (generate_objc_symtab_decl): Likewise.
	* objc-runtime-shared-support.cc: Likewise.
	* objc-runtime-shared-support.h (build_protocol_initializer): Likewise.

gcc/objcp/ChangeLog:

	* Make-lang.in: Rename .c names to .cc.
	* config-lang.in: Likewise.
	* lang-specs.h: Likewise.
	* objcp-decl.cc (objcp_end_compound_stmt): Likewise.
	* objcp-lang.cc (struct lang_hooks): Likewise.

gcc/po/ChangeLog:

	* EXCLUDES: Rename .c names to .cc.

libcpp/ChangeLog:

	* Makefile.in: Rename .c names to .cc.
	* charset.cc (convert_escape): Likewise.
	* directives.cc (directive_diagnostics): Likewise.
	(_cpp_handle_directive): Likewise.
	(lex_macro_node): Likewise.
	* include/cpplib.h (struct _cpp_file): Likewise.
	(PURE_ZERO): Likewise.
	(cpp_defined): Likewise.
	(cpp_error_at): Likewise.
	(cpp_forall_identifiers): Likewise.
	(cpp_compare_macros): Likewise.
	(cpp_get_converted_source): Likewise.
	(cpp_read_state): Likewise.
	(cpp_directive_only_process): Likewise.
	(struct cpp_decoded_char): Likewise.
	* include/line-map.h (enum lc_reason): Likewise.
	(enum location_aspect): Likewise.
	* include/mkdeps.h: Likewise.
	* init.cc (cpp_destroy): Likewise.
	(cpp_finish): Likewise.
	* internal.h (struct cpp_reader): Likewise.
	(_cpp_defined_macro_p): Likewise.
	(_cpp_backup_tokens_direct): Likewise.
	(_cpp_destroy_hashtable): Likewise.
	(_cpp_has_header): Likewise.
	(_cpp_expand_op_stack): Likewise.
	(_cpp_commit_buff): Likewise.
	(_cpp_restore_special_builtin): Likewise.
	(_cpp_bracket_include): Likewise.
	(_cpp_replacement_text_len): Likewise.
	(ufputs): Likewise.
	* line-map.cc (linemap_macro_loc_to_exp_point): Likewise.
	(linemap_check_files_exited): Likewise.
	(line_map_new_raw): Likewise.
	* traditional.cc (enum ls): Likewise.

306 files changed, 690 insertions, 690 deletions

diff --git a/gcc/config/aarch64/aarch64-builtins.cc b/gcc/config/aarch64/aarch64-builtins.cc
index 58bcbd9..215de1c 100644
--- a/gcc/config/aarch64/aarch64-builtins.cc
+++ b/gcc/config/aarch64/aarch64-builtins.cc
@@ -3177,7 +3177,7 @@ aarch64_resolve_overloaded_memtag (location_t loc,
   return NULL_TREE;
 }
 
-/* Called at aarch64_resolve_overloaded_builtin in aarch64-c.c.  */
+/* Called at aarch64_resolve_overloaded_builtin in aarch64-c.cc.  */
 tree
 aarch64_resolve_overloaded_builtin_general (location_t loc, tree function,
 					    void *pass_params)
diff --git a/gcc/config/aarch64/aarch64-protos.h b/gcc/config/aarch64/aarch64-protos.h
index 7a8604b..2636853 100644
--- a/gcc/config/aarch64/aarch64-protos.h
+++ b/gcc/config/aarch64/aarch64-protos.h
@@ -1012,7 +1012,7 @@ extern bool aarch64_classify_address (struct aarch64_address_info *, rtx,
 				      machine_mode, bool,
 				      aarch64_addr_query_type = ADDR_QUERY_M);
 
-/* Defined in common/config/aarch64-common.c.  */
+/* Defined in common/config/aarch64-common.cc.  */
 bool aarch64_handle_option (struct gcc_options *, struct gcc_options *,
 			     const struct cl_decoded_option *, location_t);
 const char *aarch64_rewrite_selected_cpu (const char *name);
@@ -1022,7 +1022,7 @@ enum aarch64_parse_opt_result aarch64_parse_extension (const char *,
 void aarch64_get_all_extension_candidates (auto_vec<const char *> *candidates);
 std::string aarch64_get_extension_string_for_isa_flags (uint64_t, uint64_t);
 
-/* Defined in aarch64-d.c  */
+/* Defined in aarch64-d.cc  */
 extern void aarch64_d_target_versions (void);
 extern void aarch64_d_register_target_info (void);
 
diff --git a/gcc/config/aarch64/aarch64-sve-builtins.cc b/gcc/config/aarch64/aarch64-sve-builtins.cc
index 6d8f2f0..3381726 100644
--- a/gcc/config/aarch64/aarch64-sve-builtins.cc
+++ b/gcc/config/aarch64/aarch64-sve-builtins.cc
@@ -1009,7 +1009,7 @@ function_builder::add_function (const function_instance &instance,
      consistent numbering scheme for function codes between the C and C++
      frontends, so that everything ties up in LTO.
 
-     Currently, tree-streamer-in.c:unpack_ts_function_decl_value_fields
+     Currently, tree-streamer-in.cc:unpack_ts_function_decl_value_fields
      validates that tree nodes returned by TARGET_BUILTIN_DECL are non-NULL and
      some node other than error_mark_node. This is a holdover from when builtin
      decls were streamed by code rather than by value.
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 1bca2a31..fdf0c9b 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -3622,7 +3622,7 @@ aarch64_regmode_natural_size (machine_mode mode)
      and similarly for predicates.  We can't independently modify
      anything smaller than that.  */
   /* ??? For now, only do this for variable-width SVE registers.
-     Doing it for constant-sized registers breaks lower-subreg.c.  */
+     Doing it for constant-sized registers breaks lower-subreg.cc.  */
   /* ??? And once that's fixed, we should probably have similar
      code for Advanced SIMD.  */
   if (!aarch64_sve_vg.is_constant ())
@@ -13909,7 +13909,7 @@ cost_plus:
     /* We can expand signed mod by power of 2 using a NEGS, two parallel
        ANDs and a CSNEG.  Assume here that CSNEG is the same as the cost of
        an unconditional negate.  This case should only ever be reached through
-       the set_smod_pow2_cheap check in expmed.c.  */
+       the set_smod_pow2_cheap check in expmed.cc.  */
       if (CONST_INT_P (XEXP (x, 1))
 	  && exact_log2 (INTVAL (XEXP (x, 1))) > 0
 	  && (mode == SImode || mode == DImode))
@@ -14699,7 +14699,7 @@ aarch64_sched_first_cycle_multipass_dfa_lookahead (void)
 
 
 /* Implement TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD as
-   autopref_multipass_dfa_lookahead_guard from haifa-sched.c.  It only
+   autopref_multipass_dfa_lookahead_guard from haifa-sched.cc.  It only
    has an effect if PARAM_SCHED_AUTOPREF_QUEUE_DEPTH > 0.  */
 
 static int
@@ -18010,7 +18010,7 @@ aarch64_option_valid_attribute_p (tree fndecl, tree, tree args, int)
 
   /* If what we're processing is the current pragma string then the
      target option node is already stored in target_option_current_node
-     by aarch64_pragma_target_parse in aarch64-c.c.  Use that to avoid
+     by aarch64_pragma_target_parse in aarch64-c.cc.  Use that to avoid
      having to re-parse the string.  This is especially useful to keep
      arm_neon.h compile times down since that header contains a lot
      of intrinsics enclosed in pragmas.  */
@@ -19340,7 +19340,7 @@ aarch64_short_vector_p (const_tree type,
 
    Note that MODE itself is not sufficient in determining whether a type
    is such a composite type or not.  This is because
-   stor-layout.c:compute_record_mode may have already changed the MODE
+   stor-layout.cc:compute_record_mode may have already changed the MODE
    (BLKmode) of a RECORD_TYPE TYPE to some other mode.  For example, a
    structure with only one field may have its MODE set to the mode of the
    field.  Also an integer mode whose size matches the size of the
@@ -22205,7 +22205,7 @@ aarch64_float_const_representable_p (rtx x)
   gcc_assert (mantissa <= 15);
 
   /* GCC internally does not use IEEE754-like encoding (where normalized
-     significands are in the range [1, 2).  GCC uses [0.5, 1) (see real.c).
+     significands are in the range [1, 2).  GCC uses [0.5, 1) (see real.cc).
      Our mantissa values are shifted 4 places to the left relative to
      normalized IEEE754 so we must modify the exponent returned by REAL_EXP
      by 5 places to correct for GCC's representation.  */
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 52ecfca..dddf133 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -636,7 +636,7 @@ extern unsigned aarch64_architecture_version;
 #define DBX_REGISTER_NUMBER(REGNO)	aarch64_dbx_register_number (REGNO)
 /* Provide a definition of DWARF_FRAME_REGNUM here so that fallback unwinders
    can use DWARF_ALT_FRAME_RETURN_COLUMN defined below.  This is just the same
-   as the default definition in dwarf2out.c.  */
+   as the default definition in dwarf2out.cc.  */
 #undef DWARF_FRAME_REGNUM
 #define DWARF_FRAME_REGNUM(REGNO)	DBX_REGISTER_NUMBER (REGNO)
 
@@ -1293,12 +1293,12 @@ extern const char *host_detect_local_cpu (int argc, const char **argv);
 #define ASM_OUTPUT_POOL_EPILOGUE  aarch64_asm_output_pool_epilogue
 
 /* This type is the user-visible __fp16, and a pointer to that type.  We
-   need it in many places in the backend.  Defined in aarch64-builtins.c.  */
+   need it in many places in the backend.  Defined in aarch64-builtins.cc.  */
 extern GTY(()) tree aarch64_fp16_type_node;
 extern GTY(()) tree aarch64_fp16_ptr_type_node;
 
 /* This type is the user-visible __bf16, and a pointer to that type.  Defined
-   in aarch64-builtins.c.  */
+   in aarch64-builtins.cc.  */
 extern GTY(()) tree aarch64_bf16_type_node;
 extern GTY(()) tree aarch64_bf16_ptr_type_node;
 
diff --git a/gcc/config/aarch64/cortex-a57-fma-steering.cc b/gcc/config/aarch64/cortex-a57-fma-steering.cc
index f7bb1ea..2d96fc4 100644
--- a/gcc/config/aarch64/cortex-a57-fma-steering.cc
+++ b/gcc/config/aarch64/cortex-a57-fma-steering.cc
@@ -49,7 +49,7 @@
    of FMUL or FMADD/FMSUB.
 
    This pass ensure that registers are renamed so that these conditions hold.
-   We reuse the existing register renaming facility from regrename.c to build
+   We reuse the existing register renaming facility from regrename.cc to build
    dependency chains and expose candidate registers for renaming.
 
 
@@ -241,7 +241,7 @@ private:
 
 /* Rename the register HEAD->regno in all the insns in the chain HEAD to any
    register not in the set UNAVAILABLE.  Adapted from rename_chains in
-   regrename.c.  */
+   regrename.cc.  */
 
 static bool
 rename_single_chain (du_head_p head, HARD_REG_SET *unavailable)
diff --git a/gcc/config/aarch64/driver-aarch64.cc b/gcc/config/aarch64/driver-aarch64.cc
index c27270d..8073a07 100644
--- a/gcc/config/aarch64/driver-aarch64.cc
+++ b/gcc/config/aarch64/driver-aarch64.cc
@@ -228,7 +228,7 @@ contains_core_p (unsigned *arr, unsigned core)
   return false;
 }
 
-/* This will be called by the spec parser in gcc.c when it sees
+/* This will be called by the spec parser in gcc.cc when it sees
    a %:local_cpu_detect(args) construct.  Currently it will be called
    with either "arch", "cpu" or "tune" as argument depending on if
    -march=native, -mcpu=native or -mtune=native is to be substituted.
diff --git a/gcc/config/aarch64/t-aarch64 b/gcc/config/aarch64/t-aarch64
index efa9e25..75b463d 100644
--- a/gcc/config/aarch64/t-aarch64
+++ b/gcc/config/aarch64/t-aarch64
@@ -34,7 +34,7 @@ s-aarch64-tune-md: $(srcdir)/config/aarch64/gentune.sh \
 		$(srcdir)/config/aarch64/aarch64-tune.md
 	$(STAMP) s-aarch64-tune-md
 
-aarch64-builtins.o: $(srcdir)/config/aarch64/aarch64-builtins.c $(CONFIG_H) \
+aarch64-builtins.o: $(srcdir)/config/aarch64/aarch64-builtins.cc $(CONFIG_H) \
   $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) expr.h $(TM_P_H) $(RECOG_H) langhooks.h \
   $(DIAGNOSTIC_CORE_H) $(OPTABS_H) \
@@ -42,7 +42,7 @@ aarch64-builtins.o: $(srcdir)/config/aarch64/aarch64-builtins.c $(CONFIG_H) \
   $(srcdir)/config/aarch64/aarch64-simd-builtin-types.def \
   aarch64-builtin-iterators.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/aarch64/aarch64-builtins.c
+		$(srcdir)/config/aarch64/aarch64-builtins.cc
 
 aarch64-sve-builtins.o: $(srcdir)/config/aarch64/aarch64-sve-builtins.cc \
   $(srcdir)/config/aarch64/aarch64-sve-builtins.def \
@@ -104,30 +104,30 @@ aarch64-builtin-iterators.h: $(srcdir)/config/aarch64/geniterators.sh \
 		$(srcdir)/config/aarch64/iterators.md > \
 		aarch64-builtin-iterators.h
 
-aarch-common.o: $(srcdir)/config/arm/aarch-common.c $(CONFIG_H) $(SYSTEM_H) \
+aarch-common.o: $(srcdir)/config/arm/aarch-common.cc $(CONFIG_H) $(SYSTEM_H) \
     coretypes.h $(TM_H) $(TM_P_H) $(RTL_H) $(TREE_H) output.h $(C_COMMON_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/arm/aarch-common.c
+		$(srcdir)/config/arm/aarch-common.cc
 
-aarch64-c.o: $(srcdir)/config/aarch64/aarch64-c.c $(CONFIG_H) $(SYSTEM_H) \
+aarch64-c.o: $(srcdir)/config/aarch64/aarch64-c.cc $(CONFIG_H) $(SYSTEM_H) \
     coretypes.h $(TM_H) $(TREE_H) output.h $(C_COMMON_H) $(TARGET_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/aarch64/aarch64-c.c
+		$(srcdir)/config/aarch64/aarch64-c.cc
 
-aarch64-d.o: $(srcdir)/config/aarch64/aarch64-d.c
+aarch64-d.o: $(srcdir)/config/aarch64/aarch64-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
 PASSES_EXTRA += $(srcdir)/config/aarch64/aarch64-passes.def
 
-cortex-a57-fma-steering.o: $(srcdir)/config/aarch64/cortex-a57-fma-steering.c \
+cortex-a57-fma-steering.o: $(srcdir)/config/aarch64/cortex-a57-fma-steering.cc \
     $(CONFIG_H) $(SYSTEM_H) $(TM_H) $(REGS_H) insn-config.h $(RTL_BASE_H) \
     dominance.h cfg.h cfganal.h $(BASIC_BLOCK_H) $(INSN_ATTR_H) $(RECOG_H) \
     output.h hash-map.h $(DF_H) $(OBSTACK_H) $(TARGET_H) $(RTL_H) \
     $(CONTEXT_H) $(TREE_PASS_H) regrename.h \
     $(srcdir)/config/aarch64/aarch64-protos.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/aarch64/cortex-a57-fma-steering.c
+		$(srcdir)/config/aarch64/cortex-a57-fma-steering.cc
 
 aarch64-speculation.o: $(srcdir)/config/aarch64/aarch64-speculation.cc \
     $(CONFIG_H) \
@@ -140,23 +140,23 @@ aarch64-speculation.o: $(srcdir)/config/aarch64/aarch64-speculation.cc \
 	  $(srcdir)/config/aarch64/aarch64-speculation.cc
 
 falkor-tag-collision-avoidance.o: \
-    $(srcdir)/config/aarch64/falkor-tag-collision-avoidance.c \
+    $(srcdir)/config/aarch64/falkor-tag-collision-avoidance.cc \
     $(CONFIG_H) $(SYSTEM_H) $(TM_H) $(REGS_H) insn-config.h $(RTL_BASE_H) \
     dominance.h cfg.h cfganal.h $(BASIC_BLOCK_H) $(INSN_ATTR_H) $(RECOG_H) \
     output.h hash-map.h $(DF_H) $(OBSTACK_H) $(TARGET_H) $(RTL_H) \
     $(CONTEXT_H) $(TREE_PASS_H) regrename.h \
     $(srcdir)/config/aarch64/aarch64-protos.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/aarch64/falkor-tag-collision-avoidance.c
+		$(srcdir)/config/aarch64/falkor-tag-collision-avoidance.cc
 
-aarch64-bti-insert.o: $(srcdir)/config/aarch64/aarch64-bti-insert.c \
+aarch64-bti-insert.o: $(srcdir)/config/aarch64/aarch64-bti-insert.cc \
     $(CONFIG_H) $(SYSTEM_H) $(TM_H) $(REGS_H) insn-config.h $(RTL_BASE_H) \
     dominance.h cfg.h cfganal.h $(BASIC_BLOCK_H) $(INSN_ATTR_H) $(RECOG_H) \
     output.h hash-map.h $(DF_H) $(OBSTACK_H) $(TARGET_H) $(RTL_H) \
     $(CONTEXT_H) $(TREE_PASS_H) regrename.h \
     $(srcdir)/config/aarch64/aarch64-protos.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/aarch64/aarch64-bti-insert.c
+		$(srcdir)/config/aarch64/aarch64-bti-insert.cc
 
 aarch64-cc-fusion.o: $(srcdir)/config/aarch64/aarch64-cc-fusion.cc \
     $(CONFIG_H) $(SYSTEM_H) $(CORETYPES_H) $(BACKEND_H) $(RTL_H) $(DF_H) \
diff --git a/gcc/config/aarch64/x-aarch64 b/gcc/config/aarch64/x-aarch64
index 8c09e04..3cf701a 100644
--- a/gcc/config/aarch64/x-aarch64
+++ b/gcc/config/aarch64/x-aarch64
@@ -1,3 +1,3 @@
-driver-aarch64.o: $(srcdir)/config/aarch64/driver-aarch64.c \
+driver-aarch64.o: $(srcdir)/config/aarch64/driver-aarch64.cc \
   $(CONFIG_H) $(SYSTEM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/aarch64/x-darwin b/gcc/config/aarch64/x-darwin
index 6d788d5..1e0bad2 100644
--- a/gcc/config/aarch64/x-darwin
+++ b/gcc/config/aarch64/x-darwin
@@ -1,3 +1,3 @@
-host-aarch64-darwin.o : $(srcdir)/config/aarch64/host-aarch64-darwin.c
+host-aarch64-darwin.o : $(srcdir)/config/aarch64/host-aarch64-darwin.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/alpha/alpha-protos.h b/gcc/config/alpha/alpha-protos.h
index 7d8f2f0..0c832bf 100644
--- a/gcc/config/alpha/alpha-protos.h
+++ b/gcc/config/alpha/alpha-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for alpha.c functions used in the md file & elsewhere.
+/* Prototypes for alpha.cc functions used in the md file & elsewhere.
    Copyright (C) 1999-2022 Free Software Foundation, Inc.
 
 This file is part of GCC.
diff --git a/gcc/config/alpha/alpha.cc b/gcc/config/alpha/alpha.cc
index 252f823..3db5337 100644
--- a/gcc/config/alpha/alpha.cc
+++ b/gcc/config/alpha/alpha.cc
@@ -702,7 +702,7 @@ alpha_scalar_mode_supported_p (scalar_mode mode)
     case E_HImode:
     case E_SImode:
     case E_DImode:
-    case E_TImode: /* via optabs.c */
+    case E_TImode: /* via optabs.cc */
       return true;
 
     case E_SFmode:
diff --git a/gcc/config/alpha/alpha.h b/gcc/config/alpha/alpha.h
index e6a9a09..c01353a 100644
--- a/gcc/config/alpha/alpha.h
+++ b/gcc/config/alpha/alpha.h
@@ -203,7 +203,7 @@ extern enum alpha_fp_trap_mode alpha_fptm;
 #define DOUBLE_TYPE_SIZE 64
 #define LONG_DOUBLE_TYPE_SIZE (TARGET_LONG_DOUBLE_128 ? 128 : 64)
 
-/* Work around target_flags dependency in ada/targtyps.c.  */
+/* Work around target_flags dependency in ada/targtyps.cc.  */
 #define WIDEST_HARDWARE_FP_SIZE 64
 
 #define	WCHAR_TYPE "unsigned int"
@@ -636,7 +636,7 @@ enum reg_class {
 
 /* Provide a definition of DWARF_FRAME_REGNUM here so that fallback unwinders
    can use DWARF_ALT_FRAME_RETURN_COLUMN defined below.  This is just the same
-   as the default definition in dwarf2out.c.  */
+   as the default definition in dwarf2out.cc.  */
 #undef DWARF_FRAME_REGNUM
 #define DWARF_FRAME_REGNUM(REG) DBX_REGISTER_NUMBER (REG)
 
@@ -661,7 +661,7 @@ enum reg_class {
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 
 #define REGNO_OK_FOR_INDEX_P(REGNO) 0
@@ -723,7 +723,7 @@ enum reg_class {
 
 /* Try a machine-dependent way of reloading an illegitimate address
    operand.  If we find one, push the reload and jump to WIN.  This
-   macro is used in only one place: `find_reloads_address' in reload.c.  */
+   macro is used in only one place: `find_reloads_address' in reload.cc.  */
 
 #define LEGITIMIZE_RELOAD_ADDRESS(X,MODE,OPNUM,TYPE,IND_L,WIN)		     \
 do {									     \
diff --git a/gcc/config/alpha/alpha.md b/gcc/config/alpha/alpha.md
index 19fa342..8751433 100644
--- a/gcc/config/alpha/alpha.md
+++ b/gcc/config/alpha/alpha.md
@@ -4667,7 +4667,7 @@
   DONE;
 })
 
-;; Block move/clear, see alpha.c for more details.
+;; Block move/clear, see alpha.cc for more details.
 ;; Argument 0 is the destination
 ;; Argument 1 is the source
 ;; Argument 2 is the length
@@ -4920,7 +4920,7 @@
 ;; an lda/ldah pair and we want to align them properly.  So we have two
 ;; unspec_volatile insns, the first of which emits the ldgp assembler macro
 ;; and the second of which emits nothing.  However, both are marked as type
-;; IADD (the default) so the alignment code in alpha.c does the right thing
+;; IADD (the default) so the alignment code in alpha.cc does the right thing
 ;; with them.
 
 (define_expand "prologue_ldgp"
diff --git a/gcc/config/alpha/driver-alpha.cc b/gcc/config/alpha/driver-alpha.cc
index 2868e54..fe17f86 100644
--- a/gcc/config/alpha/driver-alpha.cc
+++ b/gcc/config/alpha/driver-alpha.cc
@@ -41,7 +41,7 @@ along with GCC; see the file COPYING3.  If not see
 #define AMASK_LOCKPFTCHOK  0x1000       /* Safe to prefetch lock cache
 					   block.  */
 
-/* This will be called by the spec parser in gcc.c when it sees
+/* This will be called by the spec parser in gcc.cc when it sees
    a %:local_cpu_detect(args) construct.  Currently it will be called
    with either "cpu" or "tune" as argument depending on if -mcpu=native
    or -mtune=native is to be substituted.
diff --git a/gcc/config/alpha/x-alpha b/gcc/config/alpha/x-alpha
index 2b22e5e..60fa4a1 100644
--- a/gcc/config/alpha/x-alpha
+++ b/gcc/config/alpha/x-alpha
@@ -1,3 +1,3 @@
-driver-alpha.o: $(srcdir)/config/alpha/driver-alpha.c
+driver-alpha.o: $(srcdir)/config/alpha/driver-alpha.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/arc/arc-protos.h b/gcc/config/arc/arc-protos.h
index edad053..db542f0 100644
--- a/gcc/config/arc/arc-protos.h
+++ b/gcc/config/arc/arc-protos.h
@@ -97,7 +97,7 @@ extern bool arc_text_label (rtx_insn *insn);
 extern bool arc_short_comparison_p (rtx, int);
 extern bool arc_epilogue_uses (int regno);
 extern bool arc_eh_uses (int regno);
-/* insn-attrtab.c doesn't include reload.h, which declares regno_clobbered_p. */
+/* insn-attrtab.cc doesn't include reload.h, which declares regno_clobbered_p. */
 extern int regno_clobbered_p (unsigned int, rtx_insn *, machine_mode, int);
 extern bool arc_legitimize_reload_address (rtx *, machine_mode, int, int);
 extern void arc_secondary_reload_conv (rtx, rtx, rtx, bool);
diff --git a/gcc/config/arc/arc.cc b/gcc/config/arc/arc.cc
index 3096a9b..8cc1735 100644
--- a/gcc/config/arc/arc.cc
+++ b/gcc/config/arc/arc.cc
@@ -1391,7 +1391,7 @@ arc_override_options (void)
 #undef ARC_OPT
 
   /* Set cpu flags accordingly to architecture/selected cpu.  The cpu
-     specific flags are set in arc-common.c.  The architecture forces
+     specific flags are set in arc-common.cc.  The architecture forces
      the default hardware configurations in, regardless what command
      line options are saying.  The CPU optional hw options can be
      turned on or off.  */
@@ -4472,7 +4472,7 @@ static int output_sdata = 0;
 /* Print operand X (an rtx) in assembler syntax to file FILE.
    CODE is a letter or dot (`z' in `%z0') or 0 if no letter was specified.
    For `%' followed by punctuation, CODE is the punctuation and X is null.  */
-/* In final.c:output_asm_insn:
+/* In final.cc:output_asm_insn:
     'l' : label
     'a' : address
     'c' : constant address if CONSTANT_ADDRESS_P
@@ -5455,7 +5455,7 @@ arc_ccfsm_advance (rtx_insn *insn, struct arc_ccfsm *state)
 	}
 
       /* Restore recog_operand.  Getting the attributes of other insns can
-	 destroy this array, but final.c assumes that it remains intact
+	 destroy this array, but final.cc assumes that it remains intact
 	 across this call; since the insn has been recognized already we
 	 call insn_extract direct.  */
       extract_insn_cached (insn);
@@ -6542,7 +6542,7 @@ arc_arg_partial_bytes (cumulative_args_t cum_v, const function_arg_info &arg)
   arg_num = ROUND_ADVANCE_CUM (arg_num, arg.mode, arg.type);
   ret = GPR_REST_ARG_REGS (arg_num);
 
-  /* ICEd at function.c:2361, and ret is copied to data->partial */
+  /* ICEd at function.cc:2361, and ret is copied to data->partial */
     ret = (ret >= words ? 0 : ret * UNITS_PER_WORD);
 
   return ret;
@@ -9517,12 +9517,12 @@ conditionalize_nonjump (rtx pat, rtx cond, rtx insn, bool annulled)
 	}
     }
 
-  /* dwarf2out.c:dwarf2out_frame_debug_expr doesn't know
+  /* dwarf2out.cc:dwarf2out_frame_debug_expr doesn't know
      what to do with COND_EXEC.  */
   if (RTX_FRAME_RELATED_P (insn))
     {
       /* If this is the delay slot insn of an anulled branch,
-	 dwarf2out.c:scan_trace understands the anulling semantics
+	 dwarf2out.cc:scan_trace understands the anulling semantics
 	 without the COND_EXEC.  */
       gcc_assert (annulled);
       rtx note = alloc_reg_note (REG_FRAME_RELATED_EXPR, pat,
diff --git a/gcc/config/arc/arc.md b/gcc/config/arc/arc.md
index 98510ee..d4e22a4 100644
--- a/gcc/config/arc/arc.md
+++ b/gcc/config/arc/arc.md
@@ -4042,7 +4042,7 @@ core_3, archs4x, archs4xd, archs4xd_slow"
    (set_attr_alternative "length"
      [(cond
 	[(eq_attr "iscompact" "false") (const_int 4)
-	; We have to mention (match_dup 3) to convince genattrtab.c that this
+	; We have to mention (match_dup 3) to convince genattrtab.cc that this
 	; is a varying length insn.
 	 (eq (symbol_ref "1+1") (const_int 2)) (const_int 2)
 	 (gt (minus (match_dup 3) (pc)) (const_int 42)) (const_int 4)]
@@ -4663,7 +4663,7 @@ core_3, archs4x, archs4xd, archs4xd_slow"
       return \"trap_s %0\";
     }
 
-  /* Keep this message in sync with the one in arc.c:arc_expand_builtin,
+  /* Keep this message in sync with the one in arc.cc:arc_expand_builtin,
      because *.md files do not get scanned by exgettext.  */
   fatal_error (input_location,
 	       \"operand to trap_s should be an unsigned 6-bit value\");
@@ -4844,7 +4844,7 @@ core_3, archs4x, archs4xd, archs4xd_slow"
   "arc_can_use_return_insn ()"
   "")
 
- ;; Comment in final.c (insn_current_reference_address) says
+ ;; Comment in final.cc (insn_current_reference_address) says
  ;; forward branch addresses are calculated from the next insn after branch
  ;; and for backward branches, it is calculated from the branch insn start.
  ;; The shortening logic here is tuned to accomodate this behavior
@@ -5223,7 +5223,7 @@ core_3, archs4x, archs4xd, archs4xd_slow"
 ;; subdf alternative that matches a zero operand 1, which then can allow
 ;; to use bxor to flip the high bit of an integer register.
 ;; ??? we actually can't use the floating point hardware for neg, because
-;; this would not work right for -0.  OTOH optabs.c has already code
+;; this would not work right for -0.  OTOH optabs.cc has already code
 ;; to synthesyze negate by flipping the sign bit.
 
 ;;V2 instructions
diff --git a/gcc/config/arc/builtins.def b/gcc/config/arc/builtins.def
index 4604633..06d30e4 100644
--- a/gcc/config/arc/builtins.def
+++ b/gcc/config/arc/builtins.def
@@ -25,9 +25,9 @@
    NAME:    `__builtin_arc_name' will be the user-level name of the builtin.
             `ARC_BUILTIN_NAME' will be the internal builtin's id.
    N_ARGS:  Number of input arguments.  If special treatment is needed,
-            set to -1 and handle it by hand, see arc.c:arc_expand_builtin().
+            set to -1 and handle it by hand, see arc.cc:arc_expand_builtin().
    TYPE:    A tree node describing the prototype of the built-in.
-   ICODE:   Name of attached insn or expander.  If special treatment in arc.c
+   ICODE:   Name of attached insn or expander.  If special treatment in arc.cc
             is needed to expand the built-in, use `nothing'.
    MASK:    CPU selector mask.  */
 
diff --git a/gcc/config/arc/t-arc b/gcc/config/arc/t-arc
index 9f95c7a..9af2d2f 100644
--- a/gcc/config/arc/t-arc
+++ b/gcc/config/arc/t-arc
@@ -19,14 +19,14 @@
 
 TM_H += $(srcdir)/config/arc/arc-c.def
 
-driver-arc.o: $(srcdir)/config/arc/driver-arc.c \
+driver-arc.o: $(srcdir)/config/arc/driver-arc.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
-arc-c.o: $(srcdir)/config/arc/arc-c.c $(CONFIG_H) $(SYSTEM_H) \
+arc-c.o: $(srcdir)/config/arc/arc-c.cc $(CONFIG_H) $(SYSTEM_H) \
 $(TREE_H) $(TM_H) $(TM_P_H) coretypes.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/arc/arc-c.c
+		$(srcdir)/config/arc/arc-c.cc
 
 #Run `arc-cpus` if you changed something in arc-cpus.def
 
diff --git a/gcc/config/arm/arm-c.cc b/gcc/config/arm/arm-c.cc
index 5d5697f..a8697b8 100644
--- a/gcc/config/arm/arm-c.cc
+++ b/gcc/config/arm/arm-c.cc
@@ -162,7 +162,7 @@ arm_resolve_overloaded_builtin (location_t loc, tree fndecl, void *arglist)
 }
 
 /* Output C specific EABI object attributes.  These cannot be done in
-   arm.c because they require information from the C frontend.  */
+   arm.cc because they require information from the C frontend.  */
 
 static void
 arm_output_c_attributes (void)
@@ -486,7 +486,7 @@ arm_pragma_target_parse (tree args, tree pop_target)
 }
 
 /* Register target pragmas.  We need to add the hook for parsing #pragma GCC
-   option here rather than in arm.c since it will pull in various preprocessor
+   option here rather than in arm.cc since it will pull in various preprocessor
    functions, and those are not present in languages like fortran without a
    preprocessor.  */
 
diff --git a/gcc/config/arm/arm-protos.h b/gcc/config/arm/arm-protos.h
index fb365ac..cd55a9f 100644
--- a/gcc/config/arm/arm-protos.h
+++ b/gcc/config/arm/arm-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for exported functions defined in arm.c and pe.c
+/* Prototypes for exported functions defined in arm.cc and pe.c
    Copyright (C) 1999-2022 Free Software Foundation, Inc.
    Contributed by Richard Earnshaw (rearnsha@arm.com)
    Minor hacks by Nick Clifton (nickc@cygnus.com)
@@ -391,15 +391,15 @@ extern void arm_emit_eabi_attribute (const char *, int, int);
 extern void arm_reset_previous_fndecl (void);
 extern void save_restore_target_globals (tree);
 
-/* Defined in gcc/common/config/arm-common.c.  */
+/* Defined in gcc/common/config/arm-common.cc.  */
 extern const char *arm_rewrite_selected_cpu (const char *name);
 
-/* Defined in gcc/common/config/arm-c.c.  */
+/* Defined in gcc/common/config/arm-c.cc.  */
 extern void arm_lang_object_attributes_init (void);
 extern void arm_register_target_pragmas (void);
 extern void arm_cpu_cpp_builtins (struct cpp_reader *);
 
-/* Defined in arm-d.c  */
+/* Defined in arm-d.cc  */
 extern void arm_d_target_versions (void);
 extern void arm_d_register_target_info (void);
 
diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
index 084cbac..7825e36 100644
--- a/gcc/config/arm/arm.cc
+++ b/gcc/config/arm/arm.cc
@@ -12643,7 +12643,7 @@ vfp3_const_double_index (rtx x)
   /* The value of 5 here would be 4 if GCC used IEEE754-like encoding (where
      normalized significands are in the range [1, 2). (Our mantissa is shifted
      left 4 places at this point relative to normalized IEEE754 values).  GCC
-     internally uses [0.5, 1) (see real.c), so the exponent returned from
+     internally uses [0.5, 1) (see real.cc), so the exponent returned from
      REAL_EXP must be altered.  */
   exponent = 5 - exponent;
 
@@ -20801,7 +20801,7 @@ shift_op (rtx op, HOST_WIDE_INT *amountp)
    is) or not (and must be printed with an octal escape) must be made
    with reference to the *host* character set -- the situation is
    similar to that discussed in the comments above pp_c_char in
-   c-pretty-print.c.  */
+   c-pretty-print.cc.  */
 
 #define MAX_ASCII_LEN 51
 
@@ -24969,7 +24969,7 @@ thumb2_final_prescan_insn (rtx_insn *insn)
 	break;
     }
   /* Restore recog_data (getting the attributes of other insns can
-     destroy this array, but final.c assumes that it remains intact
+     destroy this array, but final.cc assumes that it remains intact
      across this call).  */
   extract_constrain_insn_cached (first_insn);
 }
@@ -25258,7 +25258,7 @@ arm_final_prescan_insn (rtx_insn *insn)
 	}
 
       /* Restore recog_data (getting the attributes of other insns can
-	 destroy this array, but final.c assumes that it remains intact
+	 destroy this array, but final.cc assumes that it remains intact
 	 across this call.  */
       extract_constrain_insn_cached (insn);
     }
@@ -28039,7 +28039,7 @@ arm_asm_output_labelref (FILE *stream, const char *name)
    the tag name in a comment so that anyone reading the assembler output
    will know which tag is being set.
 
-   This function is not static because arm-c.c needs it too.  */
+   This function is not static because arm-c.cc needs it too.  */
 
 void
 arm_emit_eabi_attribute (const char *name, int num, int val)
@@ -29326,7 +29326,7 @@ arm_small_register_classes_for_mode_p (machine_mode mode ATTRIBUTE_UNUSED)
 
 /* Implement TARGET_SHIFT_TRUNCATION_MASK.  SImode shifts use normal
    ARM insns and therefore guarantee that the shift count is modulo 256.
-   DImode shifts (those implemented by lib1funcs.S or by optabs.c)
+   DImode shifts (those implemented by lib1funcs.S or by optabs.cc)
    guarantee no particular behavior for out-of-range counts.  */
 
 static unsigned HOST_WIDE_INT
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index dacce2b..f52724d 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -79,11 +79,11 @@ extern GTY(()) rtx arm_target_insn;
 extern void (*arm_lang_output_object_attributes_hook)(void);
 
 /* This type is the user-visible __fp16.  We need it in a few places in
-   the backend.  Defined in arm-builtins.c.  */
+   the backend.  Defined in arm-builtins.cc.  */
 extern tree arm_fp16_type_node;
 
 /* This type is the user-visible __bf16.  We need it in a few places in
-   the backend.  Defined in arm-builtins.c.  */
+   the backend.  Defined in arm-builtins.cc.  */
 extern tree arm_bf16_type_node;
 extern tree arm_bf16_ptr_type_node;
 
@@ -1715,7 +1715,7 @@ typedef struct
 		bl	mcount
 		.word	LP1
 
-   profile_function() in final.c outputs the .data section, FUNCTION_PROFILER
+   profile_function() in final.cc outputs the .data section, FUNCTION_PROFILER
    will output the .text section.
 
    The ``mov ip,lr'' seems like a good idea to stick with cc convention.
@@ -2228,7 +2228,7 @@ extern int making_const_table;
    that ASM_OUTPUT_REG_PUSH will be matched with ASM_OUTPUT_REG_POP, and
    that r7 isn't used by the function profiler, so we can use it as a
    scratch reg.  WARNING: This isn't safe in the general case!  It may be
-   sensitive to future changes in final.c:profile_function.  */
+   sensitive to future changes in final.cc:profile_function.  */
 #define ASM_OUTPUT_REG_PUSH(STREAM, REGNO)		\
   do							\
     {							\
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 8a3ee06..90756fb 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -6553,7 +6553,7 @@
 ;; This pattern will be split into one of the pic_load_addr_* patterns
 ;; and a move after GCSE optimizations.
 ;;
-;; Note: Update arm.c: legitimize_pic_address() when changing this pattern.
+;; Note: Update arm.cc: legitimize_pic_address() when changing this pattern.
 (define_expand "calculate_pic_address"
   [(set (match_operand:SI 0 "register_operand")
 	(mem:SI (plus:SI (match_operand:SI 1 "register_operand")
diff --git a/gcc/config/arm/driver-arm.cc b/gcc/config/arm/driver-arm.cc
index f49e3a3..b10c1fe 100644
--- a/gcc/config/arm/driver-arm.cc
+++ b/gcc/config/arm/driver-arm.cc
@@ -40,7 +40,7 @@ struct vendor
 
 #include "arm-native.h"
 
-/* This will be called by the spec parser in gcc.c when it sees
+/* This will be called by the spec parser in gcc.cc when it sees
    a %:local_cpu_detect(args) construct.  Currently it will be called
    with either "arch", "cpu" or "tune" as argument depending on if
    -march=native, -mcpu=native or -mtune=native is to be substituted.
diff --git a/gcc/config/arm/symbian.h b/gcc/config/arm/symbian.h
index e001524..7df39170 100644
--- a/gcc/config/arm/symbian.h
+++ b/gcc/config/arm/symbian.h
@@ -22,7 +22,7 @@
    "__builtin").  Symbian OS code relies on properties of the standard
    library that go beyond those guaranteed by the ANSI/ISO standard.
    For example, "memcpy" works even with overlapping memory, like
-   "memmove".  We cannot simply set flag_no_builtin in arm.c because
+   "memmove".  We cannot simply set flag_no_builtin in arm.cc because
    (a) flag_no_builtin is not declared in language-independent code,
    and (b) that would prevent users from explicitly overriding the
    default with -fbuiltin, which may sometimes be useful.
diff --git a/gcc/config/arm/t-arm b/gcc/config/arm/t-arm
index 7133b43..041cc6e 100644
--- a/gcc/config/arm/t-arm
+++ b/gcc/config/arm/t-arm
@@ -121,12 +121,12 @@ s-arm-native: $(srcdir)/config/arm/parsecpu.awk \
 	$(SHELL) $(srcdir)/../move-if-change tmp-arm-native.h arm-native.h
 	$(STAMP) s-arm-native
 
-aarch-common.o: $(srcdir)/config/arm/aarch-common.c $(CONFIG_H) $(SYSTEM_H) \
+aarch-common.o: $(srcdir)/config/arm/aarch-common.cc $(CONFIG_H) $(SYSTEM_H) \
     coretypes.h $(TM_H) $(TM_P_H) $(RTL_H) $(TREE_H) output.h $(C_COMMON_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/arm/aarch-common.c
+		$(srcdir)/config/arm/aarch-common.cc
 
-arm.o: $(srcdir)/config/arm/arm.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
+arm.o: $(srcdir)/config/arm/arm.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
   $(INSN_ATTR_H) $(FLAGS_H) reload.h $(FUNCTION_H) \
@@ -140,7 +140,7 @@ arm.o: $(srcdir)/config/arm/arm.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(srcdir)/config/arm/arm_vfp_builtins.def \
   $(srcdir)/config/arm/arm_mve_builtins.def
 
-arm-builtins.o: $(srcdir)/config/arm/arm-builtins.c $(CONFIG_H) \
+arm-builtins.o: $(srcdir)/config/arm/arm-builtins.cc $(CONFIG_H) \
   $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) expr.h $(TM_P_H) $(RECOG_H) langhooks.h \
   $(DIAGNOSTIC_CORE_H) $(OPTABS_H) \
@@ -151,7 +151,7 @@ arm-builtins.o: $(srcdir)/config/arm/arm-builtins.c $(CONFIG_H) \
   $(srcdir)/config/arm/arm_mve_builtins.def \
   $(srcdir)/config/arm/arm-simd-builtin-types.def
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/arm/arm-builtins.c
+		$(srcdir)/config/arm/arm-builtins.cc
 
 arm-mve-builtins.o: $(srcdir)/config/arm/arm-mve-builtins.cc $(CONFIG_H) \
   $(SYSTEM_H) coretypes.h $(TM_H) $(TREE_H) \
@@ -163,12 +163,12 @@ arm-mve-builtins.o: $(srcdir)/config/arm/arm-mve-builtins.cc $(CONFIG_H) \
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
 		$(srcdir)/config/arm/arm-mve-builtins.cc
 
-arm-c.o: $(srcdir)/config/arm/arm-c.c $(CONFIG_H) $(SYSTEM_H) \
+arm-c.o: $(srcdir)/config/arm/arm-c.cc $(CONFIG_H) $(SYSTEM_H) \
     coretypes.h $(TM_H) $(TREE_H) output.h $(C_COMMON_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/arm/arm-c.c
+		$(srcdir)/config/arm/arm-c.cc
 
-arm-d.o: $(srcdir)/config/arm/arm-d.c
+arm-d.o: $(srcdir)/config/arm/arm-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/arm/thumb1.md b/gcc/config/arm/thumb1.md
index 3bcb7fa..30b8fb9 100644
--- a/gcc/config/arm/thumb1.md
+++ b/gcc/config/arm/thumb1.md
@@ -57,7 +57,7 @@
 
 ;; Changes to the constraints of this pattern must be propagated to those of
 ;; atomic additions in sync.md and to the logic for bind_old_new in
-;; arm_split_atomic_op in arm.c.  These must be at least as strict as the
+;; arm_split_atomic_op in arm.cc.  These must be at least as strict as the
 ;; constraints here and aim to be as permissive.
 (define_insn_and_split "*thumb1_addsi3"
   [(set (match_operand:SI          0 "register_operand" "=l,l,l,*rk,*hk,l,k,l,l,l")
@@ -137,7 +137,7 @@
 
 ;; Changes to the constraints of this pattern must be propagated to those of
 ;; atomic subtractions in sync.md and to the logic for bind_old_new in
-;; arm_split_atomic_op in arm.c.  These must be at least as strict as the
+;; arm_split_atomic_op in arm.cc.  These must be at least as strict as the
 ;; constraints here and aim to be as permissive.
 (define_insn "thumb1_subsi3_insn"
   [(set (match_operand:SI           0 "register_operand" "=l")
@@ -183,7 +183,7 @@
 
 ;; Changes to the constraints of this pattern must be propagated to those of
 ;; atomic bitwise ANDs and NANDs in sync.md and to the logic for bind_old_new
-;; in arm_split_atomic_op in arm.c.  These must be at least as strict as the
+;; in arm_split_atomic_op in arm.cc.  These must be at least as strict as the
 ;; constraints here and aim to be as permissive.
 (define_insn "*thumb1_andsi3_insn"
   [(set (match_operand:SI         0 "register_operand" "=l")
@@ -241,7 +241,7 @@
 
 ;; Changes to the constraints of this pattern must be propagated to those of
 ;; atomic inclusive ORs in sync.md and to the logic for bind_old_new in
-;; arm_split_atomic_op in arm.c.  These must be at least as strict as the
+;; arm_split_atomic_op in arm.cc.  These must be at least as strict as the
 ;; constraints here and aim to be as permissive.
 (define_insn "*thumb1_iorsi3_insn"
   [(set (match_operand:SI         0 "register_operand" "=l")
@@ -255,7 +255,7 @@
 
 ;; Changes to the constraints of this pattern must be propagated to those of
 ;; atomic exclusive ORs in sync.md and to the logic for bind_old_new in
-;; arm_split_atomic_op in arm.c.  These must be at least as strict as the
+;; arm_split_atomic_op in arm.cc.  These must be at least as strict as the
 ;; constraints here and aim to be as permissive.
 (define_insn "*thumb1_xorsi3_insn"
   [(set (match_operand:SI         0 "register_operand" "=l")
diff --git a/gcc/config/arm/x-arm b/gcc/config/arm/x-arm
index 51cff1e..0fc9381 100644
--- a/gcc/config/arm/x-arm
+++ b/gcc/config/arm/x-arm
@@ -1,3 +1,3 @@
-driver-arm.o: $(srcdir)/config/arm/driver-arm.c \
+driver-arm.o: $(srcdir)/config/arm/driver-arm.cc \
   $(CONFIG_H) $(SYSTEM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/avr/avr-c.cc b/gcc/config/avr/avr-c.cc
index 4f0273a..00daa2e 100644
--- a/gcc/config/avr/avr-c.cc
+++ b/gcc/config/avr/avr-c.cc
@@ -17,7 +17,7 @@
    along with GCC; see the file COPYING3.  If not see
    <http://www.gnu.org/licenses/>.  */
 
-/* Not included in avr.c since this requires C front end.  */
+/* Not included in avr.cc since this requires C front end.  */
 
 #define IN_TARGET_CODE 1
 
@@ -254,7 +254,7 @@ avr_register_target_pragmas (void)
   gcc_assert (ADDR_SPACE_GENERIC == ADDR_SPACE_RAM);
 
   /* Register address spaces.  The order must be the same as in the respective
-     enum from avr.h (or designated initializers must be used in avr.c).
+     enum from avr.h (or designated initializers must be used in avr.cc).
      We always register all address spaces even if some of them make no
      sense for some targets.  Diagnose for non-supported spaces will be
      emit by TARGET_ADDR_SPACE_DIAGNOSE_USAGE.  */
@@ -457,7 +457,7 @@ avr_cpu_cpp_builtins (struct cpp_reader *pfile)
 #if defined (WITH_DOUBLE_COMPARISON)
 #if WITH_DOUBLE_COMPARISON == 2 || WITH_DOUBLE_COMPARISON == 3
   /* The number of states a DFmode comparison libcall might take and
-     reflects what avr.c:FLOAT_LIB_COMPARE_RETURNS_BOOL returns for
+     reflects what avr.cc:FLOAT_LIB_COMPARE_RETURNS_BOOL returns for
      DFmode.  GCC's default is 3-state, but some libraries like LibF7
      implement true / false (2-state).  */
   cpp_define_formatted (pfile, "__WITH_DOUBLE_COMPARISON__=%d",
diff --git a/gcc/config/avr/avr-fixed.md b/gcc/config/avr/avr-fixed.md
index 00c85bb..542d92e 100644
--- a/gcc/config/avr/avr-fixed.md
+++ b/gcc/config/avr/avr-fixed.md
@@ -170,7 +170,7 @@
 ;** Saturated Negation and Absolute Value
 ;******************************************************************************
 
-;; Fixme: This will always result in 0.  Dunno why simplify-rtx.c says
+;; Fixme: This will always result in 0.  Dunno why simplify-rtx.cc says
 ;;   "unknown" on how to optimize this.  libgcc call would be in order,
 ;;   but the performance is *PLAIN* *HORROR* because the optimizers don't
 ;;   manage to optimize out MEMCPY that's sprincled all over fixed-bit.c  */
diff --git a/gcc/config/avr/avr-log.cc b/gcc/config/avr/avr-log.cc
index 19983cb..4c2e92aa 100644
--- a/gcc/config/avr/avr-log.cc
+++ b/gcc/config/avr/avr-log.cc
@@ -273,7 +273,7 @@ avr_log_vadump (FILE *file, const char *caller, va_list ap)
 }
 
 
-/* Called from avr.c:avr_option_override().
+/* Called from avr.cc:avr_option_override().
    Parse argument of -mlog= and set respective fields in avr_log.  */
 
 void
diff --git a/gcc/config/avr/avr-mcus.def b/gcc/config/avr/avr-mcus.def
index 489f42c..1e12ab3 100644
--- a/gcc/config/avr/avr-mcus.def
+++ b/gcc/config/avr/avr-mcus.def
@@ -40,7 +40,7 @@
    where the arguments are the fields of avr_mcu_t:
    
 	NAME	Name of the device as specified by -mmcu=<NAME>.  Also
-		used by DRIVER_SELF_SPECS and gen-avr-mmcu-specs.c for
+		used by DRIVER_SELF_SPECS and gen-avr-mmcu-specs.cc for
 		- the name of the device specific specs file
 		  in -specs=device-specs/spec-<NAME>
 		- the name of the startup file crt<NAME>.o
diff --git a/gcc/config/avr/avr-modes.def b/gcc/config/avr/avr-modes.def
index 992f8c8..0e71173 100644
--- a/gcc/config/avr/avr-modes.def
+++ b/gcc/config/avr/avr-modes.def
@@ -20,7 +20,7 @@ FRACTIONAL_INT_MODE (PSI, 24, 3);
 
 /* Make TA and UTA 64 bits wide.
    128 bit wide modes would be insane on a 8-bit machine.
-   This needs special treatment in avr.c and avr-lib.h.  */
+   This needs special treatment in avr.cc and avr-lib.h.  */
 
 ADJUST_BYTESIZE  (TA, 8);
 ADJUST_ALIGNMENT (TA, 1);
diff --git a/gcc/config/avr/avr-passes.def b/gcc/config/avr/avr-passes.def
index 066d970..d863015 100644
--- a/gcc/config/avr/avr-passes.def
+++ b/gcc/config/avr/avr-passes.def
@@ -24,7 +24,7 @@
 INSERT_PASS_BEFORE (pass_thread_prologue_and_epilogue, 1, avr_pass_pre_proep);
 
 /* This avr-specific pass (re)computes insn notes, in particular REG_DEAD
-   notes which are used by `avr.c::reg_unused_after' and branch offset
+   notes which are used by `avr.cc::reg_unused_after' and branch offset
    computations.  These notes must be correct, i.e. there must be no
    dangling REG_DEAD notes; otherwise wrong code might result, cf. PR64331.
 
diff --git a/gcc/config/avr/avr-protos.h b/gcc/config/avr/avr-protos.h
index 1ffd2f4..6023b33 100644
--- a/gcc/config/avr/avr-protos.h
+++ b/gcc/config/avr/avr-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for exported functions defined in avr.c
+/* Prototypes for exported functions defined in avr.cc
    
    Copyright (C) 2000-2022 Free Software Foundation, Inc.
    Contributed by Denis Chertykov (chertykov@gmail.com)
@@ -161,7 +161,7 @@ extern rtl_opt_pass *make_avr_pass_pre_proep (gcc::context *);
 extern rtl_opt_pass *make_avr_pass_recompute_notes (gcc::context *);
 extern rtl_opt_pass *make_avr_pass_casesi (gcc::context *);
 
-/* From avr-log.c */
+/* From avr-log.cc */
 
 #define avr_dump(...) avr_vdump (NULL, __FUNCTION__, __VA_ARGS__)
 #define avr_edump(...) avr_vdump (stderr, __FUNCTION__, __VA_ARGS__)
diff --git a/gcc/config/avr/avr.cc b/gcc/config/avr/avr.cc
index 6297392..9eec991 100644
--- a/gcc/config/avr/avr.cc
+++ b/gcc/config/avr/avr.cc
@@ -1,4 +1,4 @@
-/* Subroutines for insn-output.c for ATMEL AVR micro controllers
+/* Subroutines for insn-output.cc for ATMEL AVR micro controllers
    Copyright (C) 1998-2022 Free Software Foundation, Inc.
    Contributed by Denis Chertykov (chertykov@gmail.com)
 
@@ -734,7 +734,7 @@ avr_set_core_architecture (void)
 static void
 avr_option_override (void)
 {
-  /* caller-save.c looks for call-clobbered hard registers that are assigned
+  /* caller-save.cc looks for call-clobbered hard registers that are assigned
      to pseudos that cross calls and tries so save-restore them around calls
      in order to reduce the number of stack slots needed.
 
@@ -746,7 +746,7 @@ avr_option_override (void)
     flag_caller_saves = 0;
 
   /* Unwind tables currently require a frame pointer for correctness,
-     see toplev.c:process_options().  */
+     see toplev.cc:process_options().  */
 
   if ((flag_unwind_tables
        || flag_non_call_exceptions
@@ -772,7 +772,7 @@ avr_option_override (void)
   if (!avr_set_core_architecture())
     return;
 
-  /* Sould be set by avr-common.c */
+  /* Sould be set by avr-common.cc */
   gcc_assert (avr_long_double >= avr_double && avr_double >= 32);
 
   /* RAM addresses of some SFRs common to all devices in respective arch. */
@@ -1284,8 +1284,8 @@ avr_build_builtin_va_list (void)
      which is auto-generated by genmodes, but the compiler assigns [U]DAmode
      to the long long accum modes instead of the desired [U]TAmode.
 
-     Fix this now, right after node setup in tree.c:build_common_tree_nodes().
-     This must run before c-cppbuiltin.c:builtin_define_fixed_point_constants()
+     Fix this now, right after node setup in tree.cc:build_common_tree_nodes().
+     This must run before c-cppbuiltin.cc:builtin_define_fixed_point_constants()
      which built-in defines macros like __ULLACCUM_FBIT__ that are used by
      libgcc to detect IBIT and FBIT.  */
 
@@ -2324,7 +2324,7 @@ avr_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED, addr_space_t as)
   /* FIXME:  Non-generic addresses are not mode-dependent in themselves.
        This hook just serves to hack around PR rtl-optimization/52543 by
        claiming that non-generic addresses were mode-dependent so that
-       lower-subreg.c will skip these addresses.  lower-subreg.c sets up fake
+       lower-subreg.cc will skip these addresses.  lower-subreg.cc sets up fake
        RTXes to probe SET and MEM costs and assumes that MEM is always in the
        generic address space which is not true.  */
 
@@ -3284,7 +3284,7 @@ avr_function_arg_advance (cumulative_args_t cum_v,
       && !call_used_or_fixed_reg_p (cum->regno))
     {
       /* FIXME: We ship info on failing tail-call in struct machine_function.
-         This uses internals of calls.c:expand_call() and the way args_so_far
+         This uses internals of calls.cc:expand_call() and the way args_so_far
          is used.  targetm.function_ok_for_sibcall() needs to be extended to
          pass &args_so_far, too.  At present, CUMULATIVE_ARGS is target
          dependent so that such an extension is not wanted.  */
@@ -10049,7 +10049,7 @@ avr_asm_output_aligned_decl_common (FILE * stream,
       return;
     }
 
-  /* __gnu_lto_slim is just a marker for the linker injected by toplev.c.
+  /* __gnu_lto_slim is just a marker for the linker injected by toplev.cc.
      There is no need to trigger __do_clear_bss code for them.  */
 
   if (!startswith (name, "__gnu_lto"))
diff --git a/gcc/config/avr/avr.h b/gcc/config/avr/avr.h
index c132bda..1b948c6 100644
--- a/gcc/config/avr/avr.h
+++ b/gcc/config/avr/avr.h
@@ -321,7 +321,7 @@ enum reg_class {
 
 #define RETURN_ADDR_RTX(count, tem) avr_return_addr_rtx (count, tem)
 
-/* Don't use Push rounding. expr.c: emit_single_push_insn is broken 
+/* Don't use Push rounding. expr.cc: emit_single_push_insn is broken 
    for POST_DEC targets (PR27386).  */
 /*#define PUSH_ROUNDING(NPUSHED) (NPUSHED)*/
 
@@ -399,7 +399,7 @@ typedef struct avr_args
 #define SUPPORTS_INIT_PRIORITY 0
 
 /* We pretend jump tables are in text section because otherwise,
-   final.c will switch to .rodata before jump tables and thereby
+   final.cc will switch to .rodata before jump tables and thereby
    triggers __do_copy_data.  As we implement ASM_OUTPUT_ADDR_VEC,
    we still have full control over the jump tables themselves.  */
 #define JUMP_TABLES_IN_TEXT_SECTION 1
diff --git a/gcc/config/avr/avr.md b/gcc/config/avr/avr.md
index 30cf705..efae7ef 100644
--- a/gcc/config/avr/avr.md
+++ b/gcc/config/avr/avr.md
@@ -148,7 +148,7 @@
                        (const_int 2))]
         (const_int 2)))
 
-;; Lengths of several insns are adjusted in avr.c:adjust_insn_length().
+;; Lengths of several insns are adjusted in avr.cc:adjust_insn_length().
 ;; Following insn attribute tells if and how the adjustment has to be
 ;; done:
 ;;     no     No adjustment needed; attribute "length" is fine.
@@ -328,7 +328,7 @@
 ;; This avoids creating add/sub offsets in frame_pointer save/resore.
 ;; The 'null' receiver also avoids  problems with optimisation
 ;; not recognising incoming jmp and removing code that resets frame_pointer.
-;; The code derived from builtins.c.
+;; The code derived from builtins.cc.
 
 (define_expand "nonlocal_goto_receiver"
   [(set (reg:HI REG_Y)
@@ -346,7 +346,7 @@
 
 
 ;; Defining nonlocal_goto_receiver means we must also define this
-;; even though its function is identical to that in builtins.c
+;; even though its function is identical to that in builtins.cc
 
 (define_expand "nonlocal_goto"
   [(use (match_operand 0 "general_operand"))
diff --git a/gcc/config/avr/builtins.def b/gcc/config/avr/builtins.def
index 3bb29f6..8ed70c4 100644
--- a/gcc/config/avr/builtins.def
+++ b/gcc/config/avr/builtins.def
@@ -25,9 +25,9 @@
    NAME:    `__builtin_avr_name' will be the user-level name of the builtin.
             `AVR_BUILTIN_NAME' will be the internal builtin's id.
    N_ARGS:  Number of input arguments.  If special treatment is needed,
-            set to -1 and handle it by hand, see avr.c:avr_expand_builtin().
+            set to -1 and handle it by hand, see avr.cc:avr_expand_builtin().
    TYPE:    A tree node describing the prototype of the built-in.
-   ICODE:   Name of attached insn or expander.  If special treatment in avr.c
+   ICODE:   Name of attached insn or expander.  If special treatment in avr.cc
             is needed to expand the built-in, use `nothing'.
    LIBNAME: Name of the attached implementation in libgcc which is used if
             the builtin cannot be folded away and there is no insn.  */
diff --git a/gcc/config/avr/gen-avr-mmcu-specs.cc b/gcc/config/avr/gen-avr-mmcu-specs.cc
index 6e48cb9..bf9aa2c 100644
--- a/gcc/config/avr/gen-avr-mmcu-specs.cc
+++ b/gcc/config/avr/gen-avr-mmcu-specs.cc
@@ -27,7 +27,7 @@
 
 #define IN_GEN_AVR_MMCU_TEXI
 
-#include "avr-devices.c"
+#include "avr-devices.cc"
 
 // Get rid of "defaults.h".  We just need tm.h for `WITH_AVRLIBC' and
 // and `WITH_RTEMS'.  */
@@ -53,8 +53,8 @@
 
 static const char header[] =
   "#\n"
-  "# Generated by   : ./gcc/config/avr/gen-avr-mmcu-specs.c\n"
-  "# Generated from : ./gcc/config/gcc.c\n"
+  "# Generated by   : ./gcc/config/avr/gen-avr-mmcu-specs.cc\n"
+  "# Generated from : ./gcc/config/gcc.cc\n"
   "#                  ./gcc/config/avr/specs.h\n"
 #if defined (WITH_AVRLIBC)
   "#                  ./gcc/config/avr/avrlibc.h\n"
diff --git a/gcc/config/avr/gen-avr-mmcu-texi.cc b/gcc/config/avr/gen-avr-mmcu-texi.cc
index 05b81dd..d9c3a30 100644
--- a/gcc/config/avr/gen-avr-mmcu-texi.cc
+++ b/gcc/config/avr/gen-avr-mmcu-texi.cc
@@ -23,7 +23,7 @@
 
 #define IN_GEN_AVR_MMCU_TEXI
 
-#include "avr-devices.c"
+#include "avr-devices.cc"
 
 static const avr_mcu_t*
 mcus[sizeof avr_mcu_types / sizeof avr_mcu_types[0]];
@@ -166,9 +166,9 @@ int main (void)
 	  "gcc/doc/include/fdl.texi.\n\n");
 
   printf ("@c This file is generated automatically using\n");
-  printf ("@c gcc/config/avr/gen-avr-mmcu-texi.c from:\n");
+  printf ("@c gcc/config/avr/gen-avr-mmcu-texi.cc from:\n");
   printf ("@c	 gcc/config/avr/avr-arch.h\n");
-  printf ("@c	 gcc/config/avr/avr-devices.c\n");
+  printf ("@c	 gcc/config/avr/avr-devices.cc\n");
   printf ("@c	 gcc/config/avr/avr-mcus.def\n\n");
 
   printf ("@c Please do not edit manually.\n\n");
diff --git a/gcc/config/avr/t-avr b/gcc/config/avr/t-avr
index 17540fc..82f58dc 100644
--- a/gcc/config/avr/t-avr
+++ b/gcc/config/avr/t-avr
@@ -40,22 +40,22 @@ endif
 
 PASSES_EXTRA += $(srcdir)/config/avr/avr-passes.def
 
-driver-avr.o: $(srcdir)/config/avr/driver-avr.c \
+driver-avr.o: $(srcdir)/config/avr/driver-avr.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(srcdir)/config/avr/avr-arch.h $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
-avr-devices.o: $(srcdir)/config/avr/avr-devices.c \
+avr-devices.o: $(srcdir)/config/avr/avr-devices.cc \
   $(srcdir)/config/avr/avr-mcus.def \
   $(srcdir)/config/avr/avr-arch.h \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
-avr-c.o: $(srcdir)/config/avr/avr-c.c \
+avr-c.o: $(srcdir)/config/avr/avr-c.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(TREE_H) $(C_COMMON_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
-avr-log.o: $(srcdir)/config/avr/avr-log.c \
+avr-log.o: $(srcdir)/config/avr/avr-log.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(TREE_H) $(INPUT_H) dumpfile.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
@@ -81,13 +81,13 @@ AVR_MCUS = $(srcdir)/config/avr/avr-mcus.def
 avr-mcus: $(srcdir)/doc/avr-mmcu.texi ; @true
 
 # Make sure that native -mmcu= support is in sync with -mmcu= documentation.
-gen-avr-mmcu-texi$(build_exeext): $(srcdir)/config/avr/gen-avr-mmcu-texi.c \
-  $(AVR_MCUS) $(srcdir)/config/avr/avr-devices.c \
+gen-avr-mmcu-texi$(build_exeext): $(srcdir)/config/avr/gen-avr-mmcu-texi.cc \
+  $(AVR_MCUS) $(srcdir)/config/avr/avr-devices.cc \
   $(srcdir)/config/avr/avr-arch.h
 	$(CC_FOR_BUILD) $(CFLAGS_FOR_BUILD) $< -o $@
 
-gen-avr-mmcu-specs$(build_exeext): $(srcdir)/config/avr/gen-avr-mmcu-specs.c \
-  $(AVR_MCUS) $(srcdir)/config/avr/avr-devices.c \
+gen-avr-mmcu-specs$(build_exeext): $(srcdir)/config/avr/gen-avr-mmcu-specs.cc \
+  $(AVR_MCUS) $(srcdir)/config/avr/avr-devices.cc \
   $(srcdir)/config/avr/avr-arch.h $(TM_H)
 	$(CXX_FOR_BUILD) $(CXXFLAGS_FOR_BUILD) $< -o $@ $(INCLUDES)
 
diff --git a/gcc/config/bfin/bfin.cc b/gcc/config/bfin/bfin.cc
index a7ae41e..a89a1b4 100644
--- a/gcc/config/bfin/bfin.cc
+++ b/gcc/config/bfin/bfin.cc
@@ -708,7 +708,7 @@ frame_related_constant_load (rtx reg, HOST_WIDE_INT constant, bool related)
     insn = emit_move_insn (reg, cst);
   else
     {
-      /* We don't call split_load_immediate here, since dwarf2out.c can get
+      /* We don't call split_load_immediate here, since dwarf2out.cc can get
 	 confused about some of the more clever sequences it can generate.  */
       insn = emit_insn (gen_movsi_high (reg, cst));
       if (related)
diff --git a/gcc/config/bpf/bpf-protos.h b/gcc/config/bpf/bpf-protos.h
index 0d45558..5ee3248 100644
--- a/gcc/config/bpf/bpf-protos.h
+++ b/gcc/config/bpf/bpf-protos.h
@@ -20,7 +20,7 @@ along with GCC; see the file COPYING3.  If not see
 #ifndef GCC_BPF_PROTOS_H
 #define GCC_BPF_PROTOS_H
 
-/* Routines implemented in bpf.c.  */
+/* Routines implemented in bpf.cc.  */
 
 extern HOST_WIDE_INT bpf_initial_elimination_offset (int, int);
 extern const char *bpf_output_call (rtx);
diff --git a/gcc/config/bpf/bpf.h b/gcc/config/bpf/bpf.h
index 1d5d760..5b3f4a5 100644
--- a/gcc/config/bpf/bpf.h
+++ b/gcc/config/bpf/bpf.h
@@ -276,7 +276,7 @@ enum reg_class
 /*** Passing Function Arguments on the Stack.  */
 
 /* The eBPF ABI doesn't support passing arguments on the stack.  Only
-   in the first five registers.  Code in bpf.c assures the stack is
+   in the first five registers.  Code in bpf.cc assures the stack is
    never used when passing arguments.  However, we still have to
    define the constants below.  */
 
diff --git a/gcc/config/bpf/t-bpf b/gcc/config/bpf/t-bpf
index b37bf85..3f3cf8d 100644
--- a/gcc/config/bpf/t-bpf
+++ b/gcc/config/bpf/t-bpf
@@ -1,7 +1,7 @@
 
 TM_H += $(srcdir)/config/bpf/coreout.h
 
-coreout.o: $(srcdir)/config/bpf/coreout.c
+coreout.o: $(srcdir)/config/bpf/coreout.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/c6x/c6x-protos.h b/gcc/config/c6x/c6x-protos.h
index 9ee291b..9cbe281 100644
--- a/gcc/config/c6x/c6x-protos.h
+++ b/gcc/config/c6x/c6x-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for exported functions defined in c6x.c.
+/* Prototypes for exported functions defined in c6x.cc.
    Copyright (C) 2010-2022 Free Software Foundation, Inc.
    Contributed by CodeSourcery.
 
@@ -21,7 +21,7 @@
 #ifndef GCC_C6X_PROTOS_H
 #define GCC_C6X_PROTOS_H
 
-/* Functions defined in c6x.c.  */
+/* Functions defined in c6x.cc.  */
 
 #ifdef RTX_CODE
 extern void c6x_init_cumulative_args (CUMULATIVE_ARGS *, const_tree, rtx, int);
diff --git a/gcc/config/cr16/cr16-protos.h b/gcc/config/cr16/cr16-protos.h
index 6b717de..300bb31 100644
--- a/gcc/config/cr16/cr16-protos.h
+++ b/gcc/config/cr16/cr16-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for exported functions defined in cr16.c
+/* Prototypes for exported functions defined in cr16.cc
    Copyright (C) 2012-2022 Free Software Foundation, Inc.
    Contributed by KPIT Cummins Infosystems Limited.
 
diff --git a/gcc/config/cris/cris.cc b/gcc/config/cris/cris.cc
index 63e6834..a7807b3 100644
--- a/gcc/config/cris/cris.cc
+++ b/gcc/config/cris/cris.cc
@@ -2022,7 +2022,7 @@ cris_address_cost (rtx x, machine_mode mode ATTRIBUTE_UNUSED,
      The metric used here is (the number of cycles needed) / 2,
      where we consider equal a cycle for a word of code and a cycle to
      read memory.  FIXME: Adding "+ 1" to all values would avoid
-     returning 0, as tree-ssa-loop-ivopts.c as of r128272 "normalizes"
+     returning 0, as tree-ssa-loop-ivopts.cc as of r128272 "normalizes"
      0 to 1, thereby giving equal costs to [rN + rM] and [rN].
      Unfortunately(?) such a hack would expose other pessimizations,
      at least with g++.dg/tree-ssa/ivopts-1.C, adding insns to the
@@ -2217,7 +2217,7 @@ cris_side_effect_mode_ok (enum rtx_code code, rtx *ops,
 }
 
 /* Queue an .ident string in the queue of top-level asm statements.
-   If the front-end is done, we must be being called from toplev.c.
+   If the front-end is done, we must be being called from toplev.cc.
    In that case, do nothing.  */
 void 
 cris_asm_output_ident (const char *string)
@@ -2441,7 +2441,7 @@ cris_init_machine_status (void)
 }
 
 /* Split a 2 word move (DI or presumably DF) into component parts.
-   Originally a copy of gen_split_move_double in m32r.c.  */
+   Originally a copy of gen_split_move_double in m32r.cc.  */
 
 rtx
 cris_split_movdx (rtx *operands)
@@ -3270,7 +3270,7 @@ cris_emit_movem_store (rtx dest, rtx nregs_rtx, int increment,
 
   insn = emit_insn (gen_rtx_PARALLEL (VOIDmode, vec));
 
-  /* Because dwarf2out.c handles the insns in a parallel as a sequence,
+  /* Because dwarf2out.cc handles the insns in a parallel as a sequence,
      we need to keep the stack adjustment separate, after the
      MEM-setters.  Else the stack-adjustment in the second component of
      the parallel would be mishandled; the offsets for the SETs that
diff --git a/gcc/config/cris/cris.h b/gcc/config/cris/cris.h
index 8235509..c623d08 100644
--- a/gcc/config/cris/cris.h
+++ b/gcc/config/cris/cris.h
@@ -317,7 +317,7 @@ extern int cris_cpu_version;
     Note that to make this macro affect the alignment of stack
    locals, a fix was required, and special precautions when handling
    the stack pointer in various other macros (TARGET_ASM_FUNCTION_PROLOGUE
-   et al) were required.  See file "function.c".  If you would just define
+   et al) were required.  See file "function.cc".  If you would just define
    this macro, it would only affect the builtin alloca and variable
    local data (non-ANSI, non-K&R, Gnu C extension).  */
 #define STACK_BOUNDARY \
@@ -493,7 +493,7 @@ enum reg_class
 #define INDEX_REG_CLASS GENERAL_REGS
 
 /* Since it uses reg_renumber, it is safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 #define REGNO_OK_FOR_BASE_P(REGNO)					\
  ((REGNO) <= CRIS_LAST_GENERAL_REGISTER					\
@@ -572,7 +572,7 @@ enum reg_class
    number and dwarf frame register, we would either need to include all
    registers in the gcc description (with some marked fixed of course), or
    an inverse mapping from dwarf register to gcc register.  There is one
-   need in dwarf2out.c:expand_builtin_init_dwarf_reg_sizes.  Right now, I
+   need in dwarf2out.cc:expand_builtin_init_dwarf_reg_sizes.  Right now, I
    don't see that we need exact correspondence between DWARF *frame*
    registers and DBX_REGISTER_NUMBER, so map them onto GCC registers.  */
 #define DWARF_FRAME_REGNUM(REG) (REG)
@@ -657,7 +657,7 @@ struct cum_args {int regs;};
 
 /* Node: Function entry */
 
-/* See cris.c for TARGET_ASM_FUNCTION_PROLOGUE and
+/* See cris.cc for TARGET_ASM_FUNCTION_PROLOGUE and
    TARGET_ASM_FUNCTION_EPILOGUE.  */
 
 /* Node: Profiling */
diff --git a/gcc/config/cris/cris.opt b/gcc/config/cris/cris.opt
index a50764b..a417dd8 100644
--- a/gcc/config/cris/cris.opt
+++ b/gcc/config/cris/cris.opt
@@ -151,7 +151,7 @@ Use the most feature-enabling options allowed by other options.
 ; FIXME: The following comment relates to gcc before cris.opt.
 ; Check if it's still valid:
 ; We must call it "override-" since calling it "no-" will cause
-; gcc.c to forget it, if there's a "later" -mbest-lib-options.
+; gcc.cc to forget it, if there's a "later" -mbest-lib-options.
 ; Kludgy, but needed for some multilibbed files.
 moverride-best-lib-options
 Target RejectNegative
diff --git a/gcc/config/cris/sync.md b/gcc/config/cris/sync.md
index 798bafc..ec4212a 100644
--- a/gcc/config/cris/sync.md
+++ b/gcc/config/cris/sync.md
@@ -185,7 +185,7 @@
 
 ;; This pattern is more-or-less assumed to always exist if any of the
 ;; other atomic patterns exist (see e.g.  comment at the
-;; can_compare_and_swap_p call in omp-low.c, 4.8 era).  We'd slightly
+;; can_compare_and_swap_p call in omp-low.cc, 4.8 era).  We'd slightly
 ;; prefer atomic_exchange<mode> over this, but having both would be
 ;; redundant.
 ;; FIXME: handle memory without side-effects for operand[3].
diff --git a/gcc/config/csky/csky.cc b/gcc/config/csky/csky.cc
index 08e4f3e..e315e09 100644
--- a/gcc/config/csky/csky.cc
+++ b/gcc/config/csky/csky.cc
@@ -5694,7 +5694,7 @@ csky_expand_prologue (void)
 
       /* If we have a parameter passed partially in regs and partially
 	 in memory, the registers will have been stored to memory already
-	 in function.c.  So we only need to copy varargs from registers
+	 in function.cc.  So we only need to copy varargs from registers
 	 to stack.  */
       if (cfun->machine->uses_anonymous_args)
 	{
diff --git a/gcc/config/darwin-c.cc b/gcc/config/darwin-c.cc
index 9f46924..3770857 100644
--- a/gcc/config/darwin-c.cc
+++ b/gcc/config/darwin-c.cc
@@ -831,7 +831,7 @@ EXPORTED_CONST format_kind_info darwin_additional_format_types[] = {
 /* Support routines to dump the class references for NeXT ABI v1, aka
    32-bits ObjC-2.0, as top-level asms.
    The following two functions should only be called from
-   objc/objc-next-runtime-abi-01.c.  */
+   objc/objc-next-runtime-abi-01.cc.  */
 
 static void
 darwin_objc_declare_unresolved_class_reference (const char *name)
diff --git a/gcc/config/darwin-f.cc b/gcc/config/darwin-f.cc
index c447491..e1efc58 100644
--- a/gcc/config/darwin-f.cc
+++ b/gcc/config/darwin-f.cc
@@ -27,7 +27,7 @@ along with GCC; see the file COPYING3.  If not see
    However, we can define do-nothing stubs of said hooks as
    we are not interested in objc include files in Fortran.
 
-   The hooks original purpose (see also darwin-c.c):
+   The hooks original purpose (see also darwin-c.cc):
     * darwin_register_objc_includes
       Register the GNU objective-C runtime include path if STDINC.
 
diff --git a/gcc/config/darwin-sections.def b/gcc/config/darwin-sections.def
index 8b300ff..394ea16 100644
--- a/gcc/config/darwin-sections.def
+++ b/gcc/config/darwin-sections.def
@@ -17,7 +17,7 @@ along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
 /* Since Darwin's ld will not allow zero-sized objects, and gcc wants them,
-   we emit one byte (in darwin.c) when such an object is encountered.
+   we emit one byte (in darwin.cc) when such an object is encountered.
 
    This messes up section anchoring because the emitted byte is not counted
    outside the port.  To cope with this, we set aside sections for zero-sized
@@ -25,9 +25,9 @@ along with GCC; see the file COPYING3.  If not see
    ("zobj_" sections, below).
    
    Items that might be coalesced by the linker are prevented from participating,
-   (and those in mergeable sections are disallowed in varasm.c).  */
+   (and those in mergeable sections are disallowed in varasm.cc).  */
 
-/* The .text section is generated in varasm.c  */
+/* The .text section is generated in varasm.cc  */
 DEF_SECTION (text_coal_section, SECTION_CODE|SECTION_NO_ANCHOR,
 	     ".section __TEXT,__textcoal_nt,coalesced,pure_instructions", 0)
 
@@ -62,7 +62,7 @@ DEF_SECTION (const_coal_section, SECTION_NO_ANCHOR,
 DEF_SECTION (zobj_const_section, SECTION_NO_ANCHOR, 
 	     ".section\t__DATA,__zobj_const", 0)
 
-/* Write-able data.  '.data'  handled in varasm.c  */
+/* Write-able data.  '.data'  handled in varasm.cc  */
 DEF_SECTION (static_data_section, SECTION_WRITE, ".static_data", 0)
 DEF_SECTION (data_coal_section, SECTION_WRITE|SECTION_NO_ANCHOR,
 	     ".section __DATA,__datacoal_nt,coalesced", 0)
diff --git a/gcc/config/darwin.cc b/gcc/config/darwin.cc
index 3805743..783fe3c 100644
--- a/gcc/config/darwin.cc
+++ b/gcc/config/darwin.cc
@@ -212,7 +212,7 @@ output_objc_section_asm_op (const char *directive)
       else
 	for (i = 0; i < ARRAY_SIZE (tomarkv2); i++)
 	  switch_to_section (darwin_sections[tomarkv2[i]]);
-      /* Make sure we don't get varasm.c out of sync with us.  */
+      /* Make sure we don't get varasm.cc out of sync with us.  */
       switch_to_section (saved_in_section);
     }
   output_section_asm_op (directive);
@@ -2346,7 +2346,7 @@ fprintf (file, "# dadon: %s %s (%llu, %u) local %d weak %d"
      They must be made at least one byte, and the section containing must be
      marked as unsuitable for section-anchors (see storage allocators below).
 
-     For non-zero objects this output is handled by varasm.c.
+     For non-zero objects this output is handled by varasm.cc.
   */
   if (!size)
     {
@@ -2605,7 +2605,7 @@ fprintf (fp, "# albss: %s (%lld,%d) ro %d cst %d stat %d com %d"
 	pub, weak, one, (unsigned long)DECL_INITIAL (decl));
 #endif
 
-  /* ObjC metadata can get put in BSS because varasm.c decides it's BSS
+  /* ObjC metadata can get put in BSS because varasm.cc decides it's BSS
      before the target has a chance to comment.  */
   if ((meta = is_objc_metadata (decl)))
     {
@@ -2730,7 +2730,7 @@ fprintf (fp, "# adcom: %s (%lld,%d) ro %d cst %d stat %d com %d pub %d"
 	TREE_PUBLIC (decl), weak, one, (unsigned long)DECL_INITIAL (decl));
 #endif
 
-  /* ObjC metadata can get put in BSS because varasm.c decides it's BSS
+  /* ObjC metadata can get put in BSS because varasm.cc decides it's BSS
      before the target has a chance to comment.  */
   if ((meta = is_objc_metadata (decl)))
     {
@@ -2806,7 +2806,7 @@ fprintf (fp, "# adloc: %s (%lld,%d) ro %d cst %d stat %d one %d pub %d"
 	weak , (unsigned long)DECL_INITIAL (decl));
 #endif
 
-  /* ObjC metadata can get put in BSS because varasm.c decides it's BSS
+  /* ObjC metadata can get put in BSS because varasm.cc decides it's BSS
      before the target has a chance to comment.  */
   if ((meta = is_objc_metadata (decl)))
     {
diff --git a/gcc/config/darwin.h b/gcc/config/darwin.h
index a78476a..ceb043a 100644
--- a/gcc/config/darwin.h
+++ b/gcc/config/darwin.h
@@ -323,7 +323,7 @@ extern GTY(()) int darwin_ms_struct;
   } while (0)
 
 /* Machine dependent cpp options.  Don't add more options here, add
-   them to darwin_cpp_builtins in darwin-c.c.  */
+   them to darwin_cpp_builtins in darwin-c.cc.  */
 
 #undef	CPP_SPEC
 #define CPP_SPEC "%{static:%{!dynamic:-D__STATIC__}}%{!static:-D__DYNAMIC__}" \
@@ -586,7 +586,7 @@ extern GTY(()) int darwin_ms_struct;
 #endif
 
 #if HAVE_GNU_AS
-/* The options are added in gcc.c for this case.  */
+/* The options are added in gcc.cc for this case.  */
 #define ASM_OPTIONS ""
 #else
 /* When we detect that we're cctools or llvm as, we need to insert the right
diff --git a/gcc/config/elfos.h b/gcc/config/elfos.h
index 2e0c709..acb3762 100644
--- a/gcc/config/elfos.h
+++ b/gcc/config/elfos.h
@@ -466,7 +466,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
   default_elf_asm_output_ascii ((FILE), (STR), (LENGTH))
 
 /* Allow the use of the -frecord-gcc-switches switch via the
-   elf_record_gcc_switches function defined in varasm.c.  */
+   elf_record_gcc_switches function defined in varasm.cc.  */
 #undef  TARGET_ASM_RECORD_GCC_SWITCHES
 #define TARGET_ASM_RECORD_GCC_SWITCHES elf_record_gcc_switches
 
diff --git a/gcc/config/epiphany/epiphany-sched.md b/gcc/config/epiphany/epiphany-sched.md
index d7fa0fb..d347ce6 100644
--- a/gcc/config/epiphany/epiphany-sched.md
+++ b/gcc/config/epiphany/epiphany-sched.md
@@ -77,7 +77,7 @@
   "issue,issue+int,issue+int,issue+int,int")
 
 ;; Loads have a latency of two.
-;; Note that we fix up the latency of post_modify in epiphany.c:epiphany_adjust_cost
+;; Note that we fix up the latency of post_modify in epiphany.cc:epiphany_adjust_cost
 
 (define_insn_reservation "load" 3
   (and (eq_attr "pipe_model" "epiphany")
diff --git a/gcc/config/epiphany/epiphany.cc b/gcc/config/epiphany/epiphany.cc
index c9c3215..f8c0493 100644
--- a/gcc/config/epiphany/epiphany.cc
+++ b/gcc/config/epiphany/epiphany.cc
@@ -1512,7 +1512,7 @@ epiphany_function_value (const_tree ret_type,
   /* We must change the mode like PROMOTE_MODE does.
      ??? PROMOTE_MODE is ignored for non-scalar types.
      The set of types tested here has to be kept in sync
-     with the one in explow.c:promote_mode.  */
+     with the one in explow.cc:promote_mode.  */
   if (GET_MODE_CLASS (mode) == MODE_INT
       && GET_MODE_SIZE (mode) < 4
       && (TREE_CODE (ret_type) == INTEGER_TYPE
diff --git a/gcc/config/epiphany/epiphany.h b/gcc/config/epiphany/epiphany.h
index 2bedaac..8c723845a 100644
--- a/gcc/config/epiphany/epiphany.h
+++ b/gcc/config/epiphany/epiphany.h
@@ -378,7 +378,7 @@ extern enum reg_class epiphany_regno_reg_class[FIRST_PSEUDO_REGISTER];
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 #define REGNO_OK_FOR_BASE_P(REGNO) \
 ((REGNO) < FIRST_PSEUDO_REGISTER || (unsigned) reg_renumber[REGNO] < FIRST_PSEUDO_REGISTER)
@@ -551,7 +551,7 @@ typedef struct GTY (()) machine_function
     && epiphany_is_interrupt_p (current_function_decl)) \
    ? IRET_REGNUM : GPR_LR)
 /* This is not only for dwarf unwind info, but also for the benefit of
-   df-scan.c to tell it that LR is live at the function start.  */
+   df-scan.cc to tell it that LR is live at the function start.  */
 #define INCOMING_RETURN_ADDR_RTX gen_rtx_REG (Pmode, EPIPHANY_RETURN_REGNO)
 
 /* However, we haven't implemented the rest needed for dwarf2 unwind info.  */
@@ -662,7 +662,7 @@ typedef struct GTY (()) machine_function
 #define NO_FUNCTION_CSE 1
 
 /* Section selection.  */
-/* WARNING: These section names also appear in dwarf2out.c.  */
+/* WARNING: These section names also appear in dwarf2out.cc.  */
 
 #define TEXT_SECTION_ASM_OP	"\t.section .text"
 #define DATA_SECTION_ASM_OP	"\t.section .data"
diff --git a/gcc/config/epiphany/mode-switch-use.cc b/gcc/config/epiphany/mode-switch-use.cc
index 5d5058e..887550a 100644
--- a/gcc/config/epiphany/mode-switch-use.cc
+++ b/gcc/config/epiphany/mode-switch-use.cc
@@ -1,5 +1,5 @@
 /* Insert USEs in instructions that require mode switching.
-   This should probably be merged into mode-switching.c .
+   This should probably be merged into mode-switching.cc .
    Copyright (C) 2011-2022 Free Software Foundation, Inc.
    Contributed by Embecosm on behalf of Adapteva, Inc.
 
diff --git a/gcc/config/epiphany/predicates.md b/gcc/config/epiphany/predicates.md
index 2d25ba8..5504e29 100644
--- a/gcc/config/epiphany/predicates.md
+++ b/gcc/config/epiphany/predicates.md
@@ -246,7 +246,7 @@
       return REGNO (cc) == CC_REGNUM;
     /* From combiner.  */
     case E_QImode: case E_SImode: case E_SFmode: case E_HImode:
-    /* From cse.c:dead_libcall_p.  */
+    /* From cse.cc:dead_libcall_p.  */
     case E_DFmode:
       return 0;
     default:
diff --git a/gcc/config/epiphany/t-epiphany b/gcc/config/epiphany/t-epiphany
index 4baaee2..27a8052 100644
--- a/gcc/config/epiphany/t-epiphany
+++ b/gcc/config/epiphany/t-epiphany
@@ -17,13 +17,13 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-mode-switch-use.o : $(srcdir)/config/epiphany/mode-switch-use.c \
+mode-switch-use.o : $(srcdir)/config/epiphany/mode-switch-use.cc \
    $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(TM_P_H) $(RTL_H) \
    $(TREE_PASS_H) $(INSN_ATTR_H) $(EMIT_RTL_H) $(FUNCTION_H) $(RECOG_H) \
    insn-config.h $(DF_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $<
 
-resolve-sw-modes.o : $(srcdir)/config/epiphany/resolve-sw-modes.c \
+resolve-sw-modes.o : $(srcdir)/config/epiphany/resolve-sw-modes.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(MACHMODE_H) $(TM_H) hard-reg-set.h \
   $(TM_P_H) $(VEC_H) sbitmap.h $(BASIC_BLOCK_H) $(DF_H) $(RTL_H) \
   insn-config.h insn-codes.h $(EMIT_RTL_H) $(RECOG_H) $(FUNCTION_H) \
diff --git a/gcc/config/fr30/fr30-protos.h b/gcc/config/fr30/fr30-protos.h
index 97529b6..80d9498 100644
--- a/gcc/config/fr30/fr30-protos.h
+++ b/gcc/config/fr30/fr30-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for fr30.c functions used in the md file & elsewhere.
+/* Prototypes for fr30.cc functions used in the md file & elsewhere.
    Copyright (C) 1999-2022 Free Software Foundation, Inc.
 
 This file is part of GCC.
diff --git a/gcc/config/frv/frv-protos.h b/gcc/config/frv/frv-protos.h
index cd2c2ec..bc07111 100644
--- a/gcc/config/frv/frv-protos.h
+++ b/gcc/config/frv/frv-protos.h
@@ -18,7 +18,7 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-/* Define functions defined in frv.c */
+/* Define functions defined in frv.cc */
 extern void frv_expand_prologue			(void);
 extern void frv_expand_epilogue			(bool);
 extern frv_stack_t *frv_stack_info		(void);
diff --git a/gcc/config/frv/frv.cc b/gcc/config/frv/frv.cc
index 088a9e0..d6c3993 100644
--- a/gcc/config/frv/frv.cc
+++ b/gcc/config/frv/frv.cc
@@ -9434,7 +9434,7 @@ frv_struct_value_rtx (tree fntype ATTRIBUTE_UNUSED,
 
 #define TLS_BIAS (2048 - 16)
 
-/* This is called from dwarf2out.c via TARGET_ASM_OUTPUT_DWARF_DTPREL.
+/* This is called from dwarf2out.cc via TARGET_ASM_OUTPUT_DWARF_DTPREL.
    We need to emit DTP-relative relocations.  */
 
 static void
diff --git a/gcc/config/frv/frv.h b/gcc/config/frv/frv.h
index ad0a0f8..8cd67f7 100644
--- a/gcc/config/frv/frv.h
+++ b/gcc/config/frv/frv.h
@@ -1525,7 +1525,7 @@ do {									\
 
 #undef ASM_OUTPUT_ALIGNED_LOCAL
 
-/* This is for final.c, because it is used by ASM_DECLARE_OBJECT_NAME.  */
+/* This is for final.cc, because it is used by ASM_DECLARE_OBJECT_NAME.  */
 extern int size_directive_output;
 
 /* Like `ASM_OUTPUT_ALIGNED_LOCAL' except that it takes an additional
diff --git a/gcc/config/ft32/ft32-protos.h b/gcc/config/ft32/ft32-protos.h
index f9d8e20..6cc777e 100644
--- a/gcc/config/ft32/ft32-protos.h
+++ b/gcc/config/ft32/ft32-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for ft32.c functions used in the md file & elsewhere.
+/* Prototypes for ft32.cc functions used in the md file & elsewhere.
    Copyright (C) 2015-2022 Free Software Foundation, Inc.
 
 This file is part of GCC.
diff --git a/gcc/config/gcn/gcn-hsa.h b/gcc/config/gcn/gcn-hsa.h
index d43f429..9b5fee9 100644
--- a/gcc/config/gcn/gcn-hsa.h
+++ b/gcc/config/gcn/gcn-hsa.h
@@ -71,7 +71,7 @@ extern unsigned int gcn_local_sym_hash (const char *name);
 #define ASM_APP_ON  ""
 #define ASM_APP_OFF ""
 
-/* Avoid the default in ../../gcc.c, which adds "-pthread", which is not
+/* Avoid the default in ../../gcc.cc, which adds "-pthread", which is not
    supported for gcn.  */
 #define GOMP_SELF_SPECS ""
 
diff --git a/gcc/config/gcn/gcn.cc b/gcc/config/gcn/gcn.cc
index e29f95e..74819c6 100644
--- a/gcc/config/gcn/gcn.cc
+++ b/gcc/config/gcn/gcn.cc
@@ -3755,7 +3755,7 @@ static void
 gcn_init_libfuncs (void)
 {
   /* BITS_PER_UNIT * 2 is 64 bits, which causes
-     optabs-libfuncs.c:gen_int_libfunc to omit TImode (i.e 128 bits)
+     optabs-libfuncs.cc:gen_int_libfunc to omit TImode (i.e 128 bits)
      libcalls that we need to support operations for that type.  Initialise
      them here instead.  */
   set_optab_libfunc (udiv_optab, TImode, "__udivti3");
diff --git a/gcc/config/gcn/mkoffload.cc b/gcc/config/gcn/mkoffload.cc
index 92c4689..94ba7ff 100644
--- a/gcc/config/gcn/mkoffload.cc
+++ b/gcc/config/gcn/mkoffload.cc
@@ -307,7 +307,7 @@ copy_early_debug_info (const char *infile, const char *outfile)
   int err;
 
   /* The simple_object code can handle extracting the debug sections.
-     This code is based on that in lto-wrapper.c.  */
+     This code is based on that in lto-wrapper.cc.  */
   int infd = open (infile, O_RDONLY | O_BINARY);
   if (infd == -1)
     return false;
diff --git a/gcc/config/gcn/t-gcn-hsa b/gcc/config/gcn/t-gcn-hsa
index c8d3af3..10e31f3 100644
--- a/gcc/config/gcn/t-gcn-hsa
+++ b/gcc/config/gcn/t-gcn-hsa
@@ -16,13 +16,13 @@
 
 GTM_H += $(HASH_TABLE_H)
 
-driver-gcn.o: $(srcdir)/config/gcn/driver-gcn.c
+driver-gcn.o: $(srcdir)/config/gcn/driver-gcn.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
 CFLAGS-mkoffload.o += $(DRIVER_DEFINES) \
 	-DGCC_INSTALL_NAME=\"$(GCC_INSTALL_NAME)\"
-mkoffload.o: $(srcdir)/config/gcn/mkoffload.c
+mkoffload.o: $(srcdir)/config/gcn/mkoffload.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 ALL_HOST_OBJS += mkoffload.o
@@ -34,7 +34,7 @@ mkoffload$(exeext): mkoffload.o collect-utils.o libcommon-target.a \
 
 CFLAGS-gcn-run.o += -DVERSION_STRING=$(PKGVERSION_s)
 COMPILE-gcn-run.o = $(filter-out -fno-rtti,$(COMPILE))
-gcn-run.o: $(srcdir)/config/gcn/gcn-run.c
+gcn-run.o: $(srcdir)/config/gcn/gcn-run.cc
 	$(COMPILE-gcn-run.o) -x c -std=gnu11 -Wno-error=pedantic $<
 	$(POSTCOMPILE)
 ALL_HOST_OBJS += gcn-run.o
@@ -45,7 +45,7 @@ gcn-run$(exeext): gcn-run.o
 MULTILIB_OPTIONS = march=gfx900/march=gfx906/march=gfx908
 MULTILIB_DIRNAMES = gfx900 gfx906 gfx908
 
-gcn-tree.o: $(srcdir)/config/gcn/gcn-tree.c
+gcn-tree.o: $(srcdir)/config/gcn/gcn-tree.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 ALL_HOST_OBJS += gcn-tree.o
diff --git a/gcc/config/gcn/t-omp-device b/gcc/config/gcn/t-omp-device
index 8461c43..cd56e2f 100644
--- a/gcc/config/gcn/t-omp-device
+++ b/gcc/config/gcn/t-omp-device
@@ -1,4 +1,4 @@
-omp-device-properties-gcn: $(srcdir)/config/gcn/gcn.c
+omp-device-properties-gcn: $(srcdir)/config/gcn/gcn.cc
 	echo kind: gpu > $@
 	echo arch: gcn >> $@
 	echo isa: fiji gfx900 gfx906 gfx908 >> $@
diff --git a/gcc/config/h8300/h8300-protos.h b/gcc/config/h8300/h8300-protos.h
index a8d6bca..e9d434c 100644
--- a/gcc/config/h8300/h8300-protos.h
+++ b/gcc/config/h8300/h8300-protos.h
@@ -23,7 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 #ifndef GCC_H8300_PROTOS_H
 #define GCC_H8300_PROTOS_H
 
-/* Declarations for functions used in insn-output.c.  */
+/* Declarations for functions used in insn-output.cc.  */
 #ifdef RTX_CODE
 extern unsigned int compute_mov_length (rtx *);
 extern const char *output_plussi (rtx *, bool);
@@ -59,7 +59,7 @@ extern int byte_accesses_mergeable_p (rtx, rtx);
 extern int same_cmp_preceding_p (rtx_insn *);
 extern int same_cmp_following_p (rtx_insn *);
 
-/* Used in builtins.c */
+/* Used in builtins.cc */
 extern rtx h8300_return_addr_rtx (int, rtx);
 
 /* Classifies an h8sx shift operation.
diff --git a/gcc/config/h8300/h8300.cc b/gcc/config/h8300/h8300.cc
index 0fc6a87..78cf15f 100644
--- a/gcc/config/h8300/h8300.cc
+++ b/gcc/config/h8300/h8300.cc
@@ -1,4 +1,4 @@
-/* Subroutines for insn-output.c for Renesas H8/300.
+/* Subroutines for insn-output.cc for Renesas H8/300.
    Copyright (C) 1992-2022 Free Software Foundation, Inc.
    Contributed by Steve Chamberlain (sac@cygnus.com),
    Jim Wilson (wilson@cygnus.com), and Doug Evans (dje@cygnus.com).
@@ -496,7 +496,7 @@ F (rtx_insn *x, bool set_it)
 /* Mark all the subexpressions of the PARALLEL rtx PAR as
    frame-related.  Return PAR.
 
-   dwarf2out.c:dwarf2out_frame_debug_expr ignores sub-expressions of a
+   dwarf2out.cc:dwarf2out_frame_debug_expr ignores sub-expressions of a
    PARALLEL rtx other than the first if they do not have the
    FRAME_RELATED flag set on them.  */
 static rtx
diff --git a/gcc/config/h8300/h8300.h b/gcc/config/h8300/h8300.h
index 9218874..9a6c78c 100644
--- a/gcc/config/h8300/h8300.h
+++ b/gcc/config/h8300/h8300.h
@@ -25,7 +25,7 @@ along with GCC; see the file COPYING3.  If not see
 
 extern int cpu_type;
 
-/* Various globals defined in h8300.c.  */
+/* Various globals defined in h8300.cc.  */
 
 extern const char *h8_push_op, *h8_pop_op, *h8_mov_op;
 extern const char * const *h8_reg_names;
@@ -447,7 +447,7 @@ struct cum_arg
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 
 #define REGNO_OK_FOR_INDEX_P(regno) 0
@@ -564,7 +564,7 @@ struct cum_arg
 
 #define BRANCH_COST(speed_p, predictable_p) 0
 
-/* Tell final.c how to eliminate redundant test instructions.  */
+/* Tell final.cc how to eliminate redundant test instructions.  */
 
 /* Here we define machine-dependent flags and fields in cc_status
    (see `conditions.h').  No extra ones are needed for the h8300.  */
diff --git a/gcc/config/i386/cygming.h b/gcc/config/i386/cygming.h
index 8ace098..4515045 100644
--- a/gcc/config/i386/cygming.h
+++ b/gcc/config/i386/cygming.h
@@ -151,7 +151,7 @@ along with GCC; see the file COPYING3.  If not see
   }									\
   while (0)
 
-/* Get tree.c to declare a target-specific specialization of
+/* Get tree.cc to declare a target-specific specialization of
    merge_decl_attributes.  */
 #define TARGET_DLLIMPORT_DECL_ATTRIBUTES 1
 
@@ -381,7 +381,7 @@ do {						\
 #define DEFAULT_PCC_STRUCT_RETURN 0
 
 /* MSVC returns aggregate types of up to 8 bytes via registers.
-   See i386.c:ix86_return_in_memory.  */
+   See i386.cc:ix86_return_in_memory.  */
 #undef MS_AGGREGATE_RETURN
 #define MS_AGGREGATE_RETURN 1
 
diff --git a/gcc/config/i386/djgpp.h b/gcc/config/i386/djgpp.h
index a4adb23..909821e 100644
--- a/gcc/config/i386/djgpp.h
+++ b/gcc/config/i386/djgpp.h
@@ -166,7 +166,7 @@ along with GCC; see the file COPYING3.  If not see
 #undef  TARGET_ASM_LTO_END
 #define TARGET_ASM_LTO_END i386_djgpp_asm_lto_end
 
-/* Function protypes for gcc/i386/djgpp.c */
+/* Function protypes for gcc/i386/djgpp.cc */
 
 void
 i386_djgpp_asm_named_section(const char *name, unsigned int flags,
diff --git a/gcc/config/i386/dragonfly.h b/gcc/config/i386/dragonfly.h
index bb57d3d..39bd280 100644
--- a/gcc/config/i386/dragonfly.h
+++ b/gcc/config/i386/dragonfly.h
@@ -41,7 +41,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #undef  NO_PROFILE_COUNTERS
 #define NO_PROFILE_COUNTERS	1
 
-/* Tell final.c that we don't need a label passed to mcount.  */
+/* Tell final.cc that we don't need a label passed to mcount.  */
 
 #undef  MCOUNT_NAME
 #define MCOUNT_NAME ".mcount"
diff --git a/gcc/config/i386/driver-i386.cc b/gcc/config/i386/driver-i386.cc
index b078236..9e0ae0b 100644
--- a/gcc/config/i386/driver-i386.cc
+++ b/gcc/config/i386/driver-i386.cc
@@ -369,7 +369,7 @@ detect_caches_intel (bool xeon_mp, unsigned max_level,
   return describe_cache (level1, level2);
 }
 
-/* This will be called by the spec parser in gcc.c when it sees
+/* This will be called by the spec parser in gcc.cc when it sees
    a %:local_cpu_detect(args) construct.  Currently it will be
    called with either "arch [32|64]" or "tune [32|64]" as argument
    depending on if -march=native or -mtune=native is to be substituted.
diff --git a/gcc/config/i386/freebsd.h b/gcc/config/i386/freebsd.h
index 2e81c5d..120e24c 100644
--- a/gcc/config/i386/freebsd.h
+++ b/gcc/config/i386/freebsd.h
@@ -39,7 +39,7 @@ along with GCC; see the file COPYING3.  If not see
 #undef  NO_PROFILE_COUNTERS
 #define NO_PROFILE_COUNTERS	1
 
-/* Tell final.c that we don't need a label passed to mcount.  */
+/* Tell final.cc that we don't need a label passed to mcount.  */
 
 #undef  MCOUNT_NAME
 #define MCOUNT_NAME ".mcount"
diff --git a/gcc/config/i386/i386-c.cc b/gcc/config/i386/i386-c.cc
index 1e1d2e9..c73c1b1 100644
--- a/gcc/config/i386/i386-c.cc
+++ b/gcc/config/i386/i386-c.cc
@@ -798,7 +798,7 @@ ix86_target_macros (void)
 
 
 /* Register target pragmas.  We need to add the hook for parsing #pragma GCC
-   option here rather than in i386.c since it will pull in various preprocessor
+   option here rather than in i386.cc since it will pull in various preprocessor
    functions, and those are not present in languages like fortran without a
    preprocessor.  */
 
diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index 5fae422..eb1930b 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -14786,7 +14786,7 @@ ix86_vector_duplicate_value (machine_mode mode, rtx target, rtx val)
 static machine_mode
 get_mode_wider_vector (machine_mode o)
 {
-  /* ??? Rely on the ordering that genmodes.c gives to vectors.  */
+  /* ??? Rely on the ordering that genmodes.cc gives to vectors.  */
   machine_mode n = GET_MODE_WIDER_MODE (o).require ();
   gcc_assert (GET_MODE_NUNITS (o) == GET_MODE_NUNITS (n) * 2);
   gcc_assert (GET_MODE_SIZE (o) == GET_MODE_SIZE (n));
diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
index 4a89979..715d9a1 100644
--- a/gcc/config/i386/i386-options.cc
+++ b/gcc/config/i386/i386-options.cc
@@ -3074,7 +3074,7 @@ ix86_set_func_type (tree fndecl)
 
 	  ix86_optimize_mode_switching[X86_DIRFLAG] = 1;
 
-	  /* Only dwarf2out.c can handle -WORD(AP) as a pointer argument.  */
+	  /* Only dwarf2out.cc can handle -WORD(AP) as a pointer argument.  */
 	  if (write_symbols != NO_DEBUG && write_symbols != DWARF2_DEBUG)
 	    sorry ("only DWARF debug format is supported for interrupt "
 		   "service routine");
diff --git a/gcc/config/i386/i386-protos.h b/gcc/config/i386/i386-protos.h
index a697dd2..6b3c951 100644
--- a/gcc/config/i386/i386-protos.h
+++ b/gcc/config/i386/i386-protos.h
@@ -17,13 +17,13 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-/* In i386-common.c.  */
+/* In i386-common.cc.  */
 extern bool ix86_handle_option (struct gcc_options *opts,
 				struct gcc_options *opts_set ATTRIBUTE_UNUSED,
 				const struct cl_decoded_option *decoded,
 				location_t loc);
 
-/* Functions in i386.c */
+/* Functions in i386.cc */
 extern bool ix86_target_stack_probe (void);
 extern bool ix86_can_use_return_insn_p (void);
 extern bool ix86_function_ms_hook_prologue (const_tree fn);
@@ -267,16 +267,16 @@ extern bool ix86_expand_vector_init_duplicate (bool, machine_mode, rtx,
 					       rtx);
 extern bool ix86_extract_perm_from_pool_constant (int*, rtx);
 
-/* In i386-c.c  */
+/* In i386-c.cc  */
 extern void ix86_target_macros (void);
 extern void ix86_register_pragmas (void);
 
-/* In i386-d.c  */
+/* In i386-d.cc  */
 extern void ix86_d_target_versions (void);
 extern void ix86_d_register_target_info (void);
 extern bool ix86_d_has_stdcall_convention (unsigned int *, unsigned int *);
 
-/* In winnt.c  */
+/* In winnt.cc  */
 extern void i386_pe_unique_section (tree, int);
 extern void i386_pe_declare_function_type (FILE *, const char *, int);
 extern void i386_pe_record_external_function (tree, const char *);
@@ -309,7 +309,7 @@ extern void i386_pe_seh_unwind_emit (FILE *, rtx_insn *);
 extern void i386_pe_seh_emit_except_personality (rtx);
 extern void i386_pe_seh_init_sections (void);
 
-/* In winnt-cxx.c and winnt-stubs.c  */
+/* In winnt-cxx.cc and winnt-stubs.cc  */
 extern void i386_pe_adjust_class_at_definition (tree);
 extern bool i386_pe_type_dllimport_p (tree);
 extern bool i386_pe_type_dllexport_p (tree);
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index fb9b626..af82886 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -1438,7 +1438,7 @@ ix86_function_arg_regno_p (int regno)
 		 && regno < FIRST_MMX_REG + MMX_REGPARM_MAX));
 
   /* TODO: The function should depend on current function ABI but
-     builtins.c would need updating then. Therefore we use the
+     builtins.cc would need updating then. Therefore we use the
      default ABI.  */
   call_abi = ix86_cfun_abi ();
 
@@ -3648,7 +3648,7 @@ ix86_function_value_regno_p (const unsigned int regno)
     case ST0_REG:
     case ST1_REG:
       /* TODO: The function should depend on current function ABI but
-       builtins.c would need updating then. Therefore we use the
+       builtins.cc would need updating then. Therefore we use the
        default ABI.  */
       if (TARGET_64BIT && ix86_cfun_abi () == MS_ABI)
 	return false;
@@ -6854,7 +6854,7 @@ ix86_compute_frame_layout (void)
   if (TARGET_SEH)
     {
       /* Force the frame pointer to point at or below the lowest register save
-	 area, see the SEH code in config/i386/winnt.c for the rationale.  */
+	 area, see the SEH code in config/i386/winnt.cc for the rationale.  */
       frame->hard_frame_pointer_offset = frame->sse_reg_save_offset;
 
       /* If we can leave the frame pointer where it is, do so; however return
@@ -11974,7 +11974,7 @@ legitimize_pe_coff_symbol (rtx addr, bool inreg)
 
 /* Try machine-dependent ways of modifying an illegitimate address
    to be legitimate.  If we find one, return the new, valid address.
-   This macro is used in only one place: `memory_address' in explow.c.
+   This macro is used in only one place: `memory_address' in explow.cc.
 
    OLDX is the address as it was before break_out_memory_refs was called.
    In some cases it is useful to look at this to decide what needs to be done.
@@ -11988,7 +11988,7 @@ legitimize_pe_coff_symbol (rtx addr, bool inreg)
    nothing needs to be done because REG can certainly go in a general reg.
 
    When -fpic is used, special handling is needed for symbolic references.
-   See comments by legitimize_pic_address in i386.c for details.  */
+   See comments by legitimize_pic_address in i386.cc for details.  */
 
 static rtx
 ix86_legitimize_address (rtx x, rtx, machine_mode mode)
@@ -12334,7 +12334,7 @@ output_pic_addr_const (FILE *file, rtx x, int code)
     }
 }
 
-/* This is called from dwarf2out.c via TARGET_ASM_OUTPUT_DWARF_DTPREL.
+/* This is called from dwarf2out.cc via TARGET_ASM_OUTPUT_DWARF_DTPREL.
    We need to emit DTP-relative relocations.  */
 
 static void ATTRIBUTE_UNUSED
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index f1bb8a8..f41e090 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -551,9 +551,9 @@ extern GTY(()) tree x86_mfence;
 
 /* -march=native handling only makes sense with compiler running on
    an x86 or x86_64 chip.  If changing this condition, also change
-   the condition in driver-i386.c.  */
+   the condition in driver-i386.cc.  */
 #if defined(__i386__) || defined(__x86_64__)
-/* In driver-i386.c.  */
+/* In driver-i386.cc.  */
 extern const char *host_detect_local_cpu (int argc, const char **argv);
 #define EXTRA_SPEC_FUNCTIONS \
   { "local_cpu_detect", host_detect_local_cpu },
@@ -873,7 +873,7 @@ extern const char *host_detect_local_cpu (int argc, const char **argv);
 
 /* Standard register usage.  */
 
-/* This processor has special stack-like registers.  See reg-stack.c
+/* This processor has special stack-like registers.  See reg-stack.cc
    for details.  */
 
 #define STACK_REGS
@@ -1662,7 +1662,7 @@ typedef struct ix86_args {
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 
 #define REGNO_OK_FOR_INDEX_P(REGNO) 					\
@@ -1724,7 +1724,7 @@ typedef struct ix86_args {
    The other macros defined here are used only in TARGET_LEGITIMATE_ADDRESS_P,
    except for CONSTANT_ADDRESS_P which is usually machine-independent.
 
-   See legitimize_pic_address in i386.c for details as to what
+   See legitimize_pic_address in i386.cc for details as to what
    constitutes a legitimate address when -fpic is used.  */
 
 #define MAX_REGS_PER_ADDRESS 2
@@ -1732,7 +1732,7 @@ typedef struct ix86_args {
 #define CONSTANT_ADDRESS_P(X)  constant_address_p (X)
 
 /* If defined, a C expression to determine the base term of address X.
-   This macro is used in only one place: `find_base_term' in alias.c.
+   This macro is used in only one place: `find_base_term' in alias.cc.
 
    It is always safe for this macro to not be defined.  It exists so
    that alias analysis can understand machine-dependent addresses.
@@ -2204,7 +2204,7 @@ extern int const svr4_dbx_register_map[FIRST_PSEUDO_REGISTER];
 #define DEFAULT_LARGE_SECTION_THRESHOLD 65536
 
 /* Which processor to tune code generation for.  These must be in sync
-   with processor_target_table in i386.c.  */ 
+   with processor_target_table in i386.cc.  */ 
 
 enum processor_type
 {
@@ -2602,7 +2602,7 @@ struct GTY(()) machine_frame_state
   HOST_WIDE_INT sp_realigned_offset;
 };
 
-/* Private to winnt.c.  */
+/* Private to winnt.cc.  */
 struct seh_frame_state;
 
 enum function_type
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index a2f095e..74da0d4 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -463,7 +463,7 @@
    (ABI_UNKNOWN		2)])
 
 ;; Insns whose names begin with "x86_" are emitted by gen_FOO calls
-;; from i386.c.
+;; from i386.cc.
 
 ;; In C guard expressions, put expressions which may be compile-time
 ;; constants first.  This allows for better optimization.  For
@@ -5206,7 +5206,7 @@
 ;; of the machinery. Please note the clobber of FLAGS_REG. In i387 control
 ;; word calculation (inserted by LCM in mode switching pass) a FLAGS_REG
 ;; clobbering insns can be used. Look at emit_i387_cw_initialization ()
-;; function in i386.c.
+;; function in i386.cc.
 (define_insn_and_split "*fix_trunc<mode>_i387_1"
   [(set (match_operand:SWI248x 0 "nonimmediate_operand")
 	(fix:SWI248x (match_operand 1 "register_operand")))
@@ -15298,7 +15298,7 @@
 
 ;; Insn emitted into the body of a function to return from a function.
 ;; This is only done if the function's epilogue is known to be simple.
-;; See comments for ix86_can_use_return_insn_p in i386.c.
+;; See comments for ix86_can_use_return_insn_p in i386.cc.
 
 (define_expand "return"
   [(simple_return)]
diff --git a/gcc/config/i386/lynx.h b/gcc/config/i386/lynx.h
index 7918cac..baa62c1 100644
--- a/gcc/config/i386/lynx.h
+++ b/gcc/config/i386/lynx.h
@@ -60,7 +60,7 @@ along with GCC; see the file COPYING3.  If not see
 
 #undef ASM_OUTPUT_ALIGN
 
-/* The file i386.c defines TARGET_HAVE_TLS unconditionally if
+/* The file i386.cc defines TARGET_HAVE_TLS unconditionally if
    HAVE_AS_TLS is defined.  HAVE_AS_TLS is defined as gas support for
    TLS is detected by configure.  We undefine it here.  */
 
diff --git a/gcc/config/i386/mmx.md b/gcc/config/i386/mmx.md
index 782da22..29d470b 100644
--- a/gcc/config/i386/mmx.md
+++ b/gcc/config/i386/mmx.md
@@ -1522,7 +1522,7 @@
 })
 
 ;; Avoid combining registers from different units in a single alternative,
-;; see comment above inline_secondary_memory_needed function in i386.c
+;; see comment above inline_secondary_memory_needed function in i386.cc
 (define_insn_and_split "*vec_extractv2sf_0"
   [(set (match_operand:SF 0 "nonimmediate_operand"     "=x, m,y ,m,f,r")
 	(vec_select:SF
@@ -1537,7 +1537,7 @@
   [(set_attr "mmx_isa" "*,*,native,native,*,*")])
 
 ;; Avoid combining registers from different units in a single alternative,
-;; see comment above inline_secondary_memory_needed function in i386.c
+;; see comment above inline_secondary_memory_needed function in i386.cc
 (define_insn "*vec_extractv2sf_1"
   [(set (match_operand:SF 0 "nonimmediate_operand"     "=y,x,x,y,x,f,r")
 	(vec_select:SF
@@ -3748,7 +3748,7 @@
 })
 
 ;; Avoid combining registers from different units in a single alternative,
-;; see comment above inline_secondary_memory_needed function in i386.c
+;; see comment above inline_secondary_memory_needed function in i386.cc
 (define_insn_and_split "*vec_extractv2si_0"
   [(set (match_operand:SI 0 "nonimmediate_operand"     "=x,m,y, m,r,r")
 	(vec_select:SI
@@ -3805,7 +3805,7 @@
   "operands[1] = gen_lowpart (SImode, operands[1]);")
 
 ;; Avoid combining registers from different units in a single alternative,
-;; see comment above inline_secondary_memory_needed function in i386.c
+;; see comment above inline_secondary_memory_needed function in i386.cc
 (define_insn "*vec_extractv2si_1"
   [(set (match_operand:SI 0 "nonimmediate_operand"     "=y,rm,x,x,y,x,r")
 	(vec_select:SI
diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index ea72aa5..34175fd 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -10463,7 +10463,7 @@
    (set_attr "mode" "DF")])
 
 ;; Avoid combining registers from different units in a single alternative,
-;; see comment above inline_secondary_memory_needed function in i386.c
+;; see comment above inline_secondary_memory_needed function in i386.cc
 (define_insn "vec_set<mode>_0"
   [(set (match_operand:VI4F_128 0 "nonimmediate_operand"
 	  "=Yr,*x,v,v,v,x,x,v,Yr ,*x ,x  ,m ,m   ,m")
@@ -12989,7 +12989,7 @@
    (set_attr "mode" "V2DF")])
 
 ;; Avoid combining registers from different units in a single alternative,
-;; see comment above inline_secondary_memory_needed function in i386.c
+;; see comment above inline_secondary_memory_needed function in i386.cc
 (define_insn "sse2_storehpd"
   [(set (match_operand:DF 0 "nonimmediate_operand"     "=m,x,Yv,x,*f,r")
 	(vec_select:DF
@@ -13038,7 +13038,7 @@
    (set_attr "mode" "V2SF,V4SF,V2SF")])
 
 ;; Avoid combining registers from different units in a single alternative,
-;; see comment above inline_secondary_memory_needed function in i386.c
+;; see comment above inline_secondary_memory_needed function in i386.cc
 (define_insn "sse2_storelpd"
   [(set (match_operand:DF 0 "nonimmediate_operand"     "=m,x,x,*f,r")
 	(vec_select:DF
@@ -13103,7 +13103,7 @@
 })
 
 ;; Avoid combining registers from different units in a single alternative,
-;; see comment above inline_secondary_memory_needed function in i386.c
+;; see comment above inline_secondary_memory_needed function in i386.cc
 (define_insn "sse2_loadhpd"
   [(set (match_operand:V2DF 0 "nonimmediate_operand"
 	  "=x,v,x,v ,o,o ,o")
@@ -13162,7 +13162,7 @@
 })
 
 ;; Avoid combining registers from different units in a single alternative,
-;; see comment above inline_secondary_memory_needed function in i386.c
+;; see comment above inline_secondary_memory_needed function in i386.cc
 (define_insn "sse2_loadlpd"
   [(set (match_operand:V2DF 0 "nonimmediate_operand"
 	  "=v,x,v,x,v,x,x,v,m,m ,m")
diff --git a/gcc/config/i386/t-cygming b/gcc/config/i386/t-cygming
index 2e954cd..d4803de 100644
--- a/gcc/config/i386/t-cygming
+++ b/gcc/config/i386/t-cygming
@@ -20,33 +20,33 @@
 # doing the build, it may not be installed yet.
 LIMITS_H_TEST = true
 
-winnt.o: $(srcdir)/config/i386/winnt.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
+winnt.o: $(srcdir)/config/i386/winnt.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(TM_H) $(RTL_H) $(REGS_H) hard-reg-set.h output.h $(TREE_H) flags.h \
   $(TM_P_H) $(HASH_TABLE_H) $(GGC_H) $(LTO_STREAMER_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-	$(srcdir)/config/i386/winnt.c
+	$(srcdir)/config/i386/winnt.cc
 
-winnt-cxx.o: $(srcdir)/config/i386/winnt-cxx.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
+winnt-cxx.o: $(srcdir)/config/i386/winnt-cxx.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(TM_H) $(TREE_H) flags.h \
   $(TM_P_H) $(HASHTAB_H) $(GGC_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-	$(srcdir)/config/i386/winnt-cxx.c
+	$(srcdir)/config/i386/winnt-cxx.cc
 
 
-winnt-stubs.o: $(srcdir)/config/i386/winnt-stubs.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
+winnt-stubs.o: $(srcdir)/config/i386/winnt-stubs.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(TM_H) $(RTL_H) $(REGS_H) hard-reg-set.h output.h $(TREE_H) flags.h \
   $(TM_P_H) $(HASHTAB_H) $(GGC_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-	$(srcdir)/config/i386/winnt-stubs.c
+	$(srcdir)/config/i386/winnt-stubs.cc
 
-winnt-d.o: $(srcdir)/config/i386/winnt-d.c
+winnt-d.o: $(srcdir)/config/i386/winnt-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-msformat-c.o: $(srcdir)/config/i386/msformat-c.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
+msformat-c.o: $(srcdir)/config/i386/msformat-c.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(TM_H) $(RTL_H) $(REGS_H) hard-reg-set.h output.h $(TREE_H) flags.h \
   $(TM_P_H) $(HASHTAB_H) $(GGC_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-	$(srcdir)/config/i386/msformat-c.c
+	$(srcdir)/config/i386/msformat-c.cc
 
 STMP_FIXINC=stmp-fixinc
diff --git a/gcc/config/i386/t-djgpp b/gcc/config/i386/t-djgpp
index dd3b32a..140f763 100644
--- a/gcc/config/i386/t-djgpp
+++ b/gcc/config/i386/t-djgpp
@@ -1,8 +1,8 @@
 
 EXTRA_OBJS += djgpp.o
 
-djgpp.o:    $(srcdir)/config/i386/djgpp.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
+djgpp.o:    $(srcdir)/config/i386/djgpp.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(TM_H) $(RTL_H) $(REGS_H) hard-reg-set.h output.h $(TREE_H) flags.h \
   $(TM_P_H) $(HASH_TABLE_H) $(GGC_H) $(LTO_STREAMER_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-	$(srcdir)/config/i386/djgpp.c
+	$(srcdir)/config/i386/djgpp.cc
diff --git a/gcc/config/i386/t-gnu-property b/gcc/config/i386/t-gnu-property
index e5add0c..fc5c6f9 100644
--- a/gcc/config/i386/t-gnu-property
+++ b/gcc/config/i386/t-gnu-property
@@ -16,6 +16,6 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-gnu-property.o: $(srcdir)/config/i386/gnu-property.c
+gnu-property.o: $(srcdir)/config/i386/gnu-property.cc
 	  $(COMPILE) $<
 	  $(POSTCOMPILE)
diff --git a/gcc/config/i386/t-i386 b/gcc/config/i386/t-i386
index 6f99b70f0..4e2a0ef 100644
--- a/gcc/config/i386/t-i386
+++ b/gcc/config/i386/t-i386
@@ -22,43 +22,43 @@ TM_H += $(srcdir)/config/i386/x86-tune.def \
 	$(srcdir)/config/i386/i386-isa.def
 PASSES_EXTRA += $(srcdir)/config/i386/i386-passes.def
 
-i386-c.o: $(srcdir)/config/i386/i386-c.c
+i386-c.o: $(srcdir)/config/i386/i386-c.cc
 	  $(COMPILE) $<
 	  $(POSTCOMPILE)
 
-x86-tune-sched.o: $(srcdir)/config/i386/x86-tune-sched.c
+x86-tune-sched.o: $(srcdir)/config/i386/x86-tune-sched.cc
 	  $(COMPILE) $<
 	  $(POSTCOMPILE)
 
-x86-tune-sched-bd.o: $(srcdir)/config/i386/x86-tune-sched-bd.c
+x86-tune-sched-bd.o: $(srcdir)/config/i386/x86-tune-sched-bd.cc
 	  $(COMPILE) $<
 	  $(POSTCOMPILE)
 
-x86-tune-sched-atom.o: $(srcdir)/config/i386/x86-tune-sched-atom.c
+x86-tune-sched-atom.o: $(srcdir)/config/i386/x86-tune-sched-atom.cc
 	  $(COMPILE) $<
 	  $(POSTCOMPILE)
 
-x86-tune-sched-core.o: $(srcdir)/config/i386/x86-tune-sched-core.c
+x86-tune-sched-core.o: $(srcdir)/config/i386/x86-tune-sched-core.cc
 	  $(COMPILE) $<
 	  $(POSTCOMPILE)
 
-i386-d.o: $(srcdir)/config/i386/i386-d.c
+i386-d.o: $(srcdir)/config/i386/i386-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-i386-options.o: $(srcdir)/config/i386/i386-options.c
+i386-options.o: $(srcdir)/config/i386/i386-options.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-i386-builtins.o: $(srcdir)/config/i386/i386-builtins.c
+i386-builtins.o: $(srcdir)/config/i386/i386-builtins.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-i386-expand.o: $(srcdir)/config/i386/i386-expand.c
+i386-expand.o: $(srcdir)/config/i386/i386-expand.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-i386-features.o: $(srcdir)/config/i386/i386-features.c
+i386-features.o: $(srcdir)/config/i386/i386-features.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/i386/t-intelmic b/gcc/config/i386/t-intelmic
index 9de4b76..95d7e53 100644
--- a/gcc/config/i386/t-intelmic
+++ b/gcc/config/i386/t-intelmic
@@ -1,6 +1,6 @@
 CFLAGS-mkoffload.o += $(DRIVER_DEFINES) -DGCC_INSTALL_NAME=\"$(GCC_INSTALL_NAME)\"
 
-mkoffload.o: $(srcdir)/config/i386/intelmic-mkoffload.c
+mkoffload.o: $(srcdir)/config/i386/intelmic-mkoffload.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 ALL_HOST_OBJS += mkoffload.o
diff --git a/gcc/config/i386/t-omp-device b/gcc/config/i386/t-omp-device
index 29350a1..cfb41ed 100644
--- a/gcc/config/i386/t-omp-device
+++ b/gcc/config/i386/t-omp-device
@@ -1,6 +1,6 @@
-omp-device-properties-i386: $(srcdir)/config/i386/i386-options.c
+omp-device-properties-i386: $(srcdir)/config/i386/i386-options.cc
 	echo kind: cpu > $@
 	echo arch: intel_mic x86 x86_64 i386 i486 i586 i686 ia32 >> $@
 	echo isa: sse4 `sed -n '/^static struct ix86_target_opts isa2\?_opts\[\] =/,/^};/p' \
-	  $(srcdir)/config/i386/i386-options.c | \
+	  $(srcdir)/config/i386/i386-options.cc | \
 	  sed -n 's/",.*$$//;s/^  { "-m//p'` >> $@
diff --git a/gcc/config/i386/winnt-cxx.cc b/gcc/config/i386/winnt-cxx.cc
index 1ea047d7..788c85c 100644
--- a/gcc/config/i386/winnt-cxx.cc
+++ b/gcc/config/i386/winnt-cxx.cc
@@ -47,7 +47,7 @@ i386_pe_type_dllimport_p (tree decl)
     return false;
   
   /* Overrides of the class dllimport decls by out-of-class definitions are 
-     handled by tree.c:merge_dllimport_decl_attributes.   */
+     handled by tree.cc:merge_dllimport_decl_attributes.   */
   return true;
 }
 
@@ -144,7 +144,7 @@ i386_pe_adjust_class_at_definition (tree t)
 	 that signals that the address of this symbol is not a compile-time
 	 constant.   Any subsequent out-of-class declaration of members wil
 	 cause the DECL_DLLIMPORT_P flag to be unset.
-	 (See  tree.c: merge_dllimport_decl_attributes).
+	 (See  tree.cc: merge_dllimport_decl_attributes).
 	 That is just right since out-of class declarations can only be a
 	 definition.   */
 
diff --git a/gcc/config/i386/winnt.cc b/gcc/config/i386/winnt.cc
index 3d5eaeb..cd71369 100644
--- a/gcc/config/i386/winnt.cc
+++ b/gcc/config/i386/winnt.cc
@@ -1,4 +1,4 @@
-/* Subroutines for insn-output.c for Windows NT.
+/* Subroutines for insn-output.cc for Windows NT.
    Contributed by Douglas Rupp (drupp@cs.washington.edu)
    Copyright (C) 1995-2022 Free Software Foundation, Inc.
 
@@ -194,7 +194,7 @@ gen_stdcall_or_fastcall_suffix (tree decl, tree id, bool fastcall)
 	return NULL_TREE;
 
       /* Quit if we hit an incomplete type.  Error is reported
-	 by convert_arguments in c-typeck.c or cp/typeck.c.  */
+	 by convert_arguments in c-typeck.cc or cp/typeck.cc.  */
       FOREACH_FUNCTION_ARGS(type, arg, args_iter)
 	{
 	  HOST_WIDE_INT parm_size;
@@ -278,7 +278,7 @@ i386_pe_mangle_decl_assembler_name (tree decl, tree id)
   return (new_id ? new_id : id);
 }
 
-/* This hook behaves the same as varasm.c/assemble_name(), but
+/* This hook behaves the same as varasm.cc/assemble_name(), but
    generates the name into memory rather than outputting it to
    a file stream.  */
 
@@ -319,7 +319,7 @@ i386_pe_encode_section_info (tree decl, rtx rtl, int first)
     }
 
   /* Mark the decl so we can tell from the rtl whether the object is
-     dllexport'd or dllimport'd.  tree.c: merge_dllimport_decl_attributes
+     dllexport'd or dllimport'd.  tree.cc: merge_dllimport_decl_attributes
      handles dllexport/dllimport override semantics.  */
   flags = (SYMBOL_REF_FLAGS (symbol) &
 	   ~(SYMBOL_FLAG_DLLIMPORT | SYMBOL_FLAG_DLLEXPORT));
diff --git a/gcc/config/i386/x-cygwin b/gcc/config/i386/x-cygwin
index 752af76..d9b9091 100644
--- a/gcc/config/i386/x-cygwin
+++ b/gcc/config/i386/x-cygwin
@@ -1,4 +1,4 @@
-host-cygwin.o : $(srcdir)/config/i386/host-cygwin.c $(CONFIG_H) $(SYSTEM_H) \
+host-cygwin.o : $(srcdir)/config/i386/host-cygwin.cc $(CONFIG_H) $(SYSTEM_H) \
   coretypes.h hosthooks.h $(HOSTHOOKS_DEF_H) toplev.h diagnostic.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/i386/host-cygwin.c
+		$(srcdir)/config/i386/host-cygwin.cc
diff --git a/gcc/config/i386/x-darwin b/gcc/config/i386/x-darwin
index 4967d69..08b6ce5 100644
--- a/gcc/config/i386/x-darwin
+++ b/gcc/config/i386/x-darwin
@@ -1,3 +1,3 @@
-host-i386-darwin.o : $(srcdir)/config/i386/host-i386-darwin.c
+host-i386-darwin.o : $(srcdir)/config/i386/host-i386-darwin.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/i386/x-i386 b/gcc/config/i386/x-i386
index 1f3db1d..29868e9 100644
--- a/gcc/config/i386/x-i386
+++ b/gcc/config/i386/x-i386
@@ -1,3 +1,3 @@
-driver-i386.o : $(srcdir)/config/i386/driver-i386.c
+driver-i386.o : $(srcdir)/config/i386/driver-i386.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/i386/x-mingw32 b/gcc/config/i386/x-mingw32
index 85c7410..d481fc3 100644
--- a/gcc/config/i386/x-mingw32
+++ b/gcc/config/i386/x-mingw32
@@ -25,10 +25,10 @@ local_includedir=$(libsubdir)/$(unlibsubdir)/..`echo $(exec_prefix) | sed -e 's|
 # code does not handle that, so we have to disable checking here.
 WERROR_FLAGS += -Wno-format
 
-host-mingw32.o : $(srcdir)/config/i386/host-mingw32.c $(CONFIG_H) $(SYSTEM_H) \
+host-mingw32.o : $(srcdir)/config/i386/host-mingw32.cc $(CONFIG_H) $(SYSTEM_H) \
   coretypes.h hosthooks.h hosthooks-def.h toplev.h $(DIAGNOSTIC_H) $(HOOKS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/i386/host-mingw32.c
+		$(srcdir)/config/i386/host-mingw32.cc
 
-driver-mingw32.o : $(srcdir)/config/i386/driver-mingw32.c $(CONFIG_H)
+driver-mingw32.o : $(srcdir)/config/i386/driver-mingw32.cc $(CONFIG_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/i386/x86-tune-sched-core.cc b/gcc/config/i386/x86-tune-sched-core.cc
index 0fe7c84..44968e8 100644
--- a/gcc/config/i386/x86-tune-sched-core.cc
+++ b/gcc/config/i386/x86-tune-sched-core.cc
@@ -37,7 +37,7 @@ along with GCC; see the file COPYING3.  If not see
 
 
 /* Model decoder of Core 2/i7.
-   Below hooks for multipass scheduling (see haifa-sched.c:max_issue)
+   Below hooks for multipass scheduling (see haifa-sched.cc:max_issue)
    track the instruction fetch block boundaries and make sure that long
    (9+ bytes) instructions are assigned to D0.  */
 
diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def
index f9eb3c2..82ca0ae 100644
--- a/gcc/config/i386/x86-tune.def
+++ b/gcc/config/i386/x86-tune.def
@@ -22,8 +22,8 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     - adding new CPU into:
 	- adding PROCESSOR_XXX to processor_type (in i386.h)
 	- possibly adding XXX into CPU attribute in i386.md
-	- adding XXX to processor_alias_table (in i386.c)
-    - introducing ix86_XXX_cost in i386.c
+	- adding XXX to processor_alias_table (in i386.cc)
+    - introducing ix86_XXX_cost in i386.cc
 	- Stringop generation table can be build based on test_stringop
 	- script (once rest of tuning is complete)
     - designing a scheduler model in
diff --git a/gcc/config/i386/xm-djgpp.h b/gcc/config/i386/xm-djgpp.h
index 8926524..1aff35f 100644
--- a/gcc/config/i386/xm-djgpp.h
+++ b/gcc/config/i386/xm-djgpp.h
@@ -39,7 +39,7 @@ along with GCC; see the file COPYING3.  If not see
 #define STANDARD_STARTFILE_PREFIX_1 "/dev/env/DJDIR/lib/"
 
 /* Define STANDARD_STARTFILE_PREFIX_2 equal to STANDARD_STARTFILE_PREFIX_1
-   to avoid gcc.c redefining it to /usr/lib */
+   to avoid gcc.cc redefining it to /usr/lib */
 #undef STANDARD_STARTFILE_PREFIX_2
 #define STANDARD_STARTFILE_PREFIX_1 "/dev/env/DJDIR/lib/"
 
@@ -92,7 +92,7 @@ along with GCC; see the file COPYING3.  If not see
       } \
   } while (0)
 
-/* Canonicalize paths containing '/dev/env/'; used in prefix.c.
+/* Canonicalize paths containing '/dev/env/'; used in prefix.cc.
    _fixpath is a djgpp-specific function to canonicalize a path.
    "/dev/env/DJDIR" evaluates to "c:/djgpp" if DJDIR is "c:/djgpp" for
    example.  It removes any trailing '/', so add it back.  */
diff --git a/gcc/config/ia64/freebsd.h b/gcc/config/ia64/freebsd.h
index 7c978f2..e3ab57e 100644
--- a/gcc/config/ia64/freebsd.h
+++ b/gcc/config/ia64/freebsd.h
@@ -37,8 +37,8 @@ along with GCC; see the file COPYING3.  If not see
 /************************[  Target stuff  ]***********************************/
 
 /* Define the actual types of some ANSI-mandated types.  
-   Needs to agree with <machine/ansi.h>.  GCC defaults come from c-decl.c,
-   c-common.c, and config/<arch>/<arch>.h.  */
+   Needs to agree with <machine/ansi.h>.  GCC defaults come from c-decl.cc,
+   c-common.cc, and config/<arch>/<arch>.h.  */
 
 /* Earlier headers may get this wrong for FreeBSD.
    We use the GCC defaults instead.  */
diff --git a/gcc/config/ia64/hpux.h b/gcc/config/ia64/hpux.h
index fb196a0..fa705d7 100644
--- a/gcc/config/ia64/hpux.h
+++ b/gcc/config/ia64/hpux.h
@@ -131,7 +131,7 @@ do {								\
 #define REGISTER_TARGET_PRAGMAS() \
   c_register_pragma (0, "builtin", ia64_hpux_handle_builtin_pragma)
 
-/* Tell ia64.c that we are using the HP linker and we should delay output of
+/* Tell ia64.cc that we are using the HP linker and we should delay output of
    function extern declarations so that we don't output them for functions
    which are never used (and may not be defined).  */
 
diff --git a/gcc/config/ia64/ia64-protos.h b/gcc/config/ia64/ia64-protos.h
index 21957c4..77e0cf7 100644
--- a/gcc/config/ia64/ia64-protos.h
+++ b/gcc/config/ia64/ia64-protos.h
@@ -20,7 +20,7 @@ along with GCC; see the file COPYING3.  If not see
 /* Shared between the driver and cc1.  */
 extern enum unwind_info_type ia64_except_unwind_info (struct gcc_options *);
 
-/* Functions defined in ia64.c */
+/* Functions defined in ia64.cc */
 
 extern int bundling_p;
 #ifdef RTX_CODE
diff --git a/gcc/config/ia64/ia64.cc b/gcc/config/ia64/ia64.cc
index 829cf73..f9fb681 100644
--- a/gcc/config/ia64/ia64.cc
+++ b/gcc/config/ia64/ia64.cc
@@ -5319,7 +5319,7 @@ ia64_function_value_regno_p (const unsigned int regno)
           || (regno >= FR_RET_FIRST && regno <= FR_RET_LAST));
 }
 
-/* This is called from dwarf2out.c via TARGET_ASM_OUTPUT_DWARF_DTPREL.
+/* This is called from dwarf2out.cc via TARGET_ASM_OUTPUT_DWARF_DTPREL.
    We need to emit DTP-relative relocations.  */
 
 static void
@@ -5936,7 +5936,7 @@ ia64_secondary_reload_class (enum reg_class rclass,
 	 enabled, because paradoxical subregs are not accepted by
 	 register_operand when INSN_SCHEDULING is defined.  Or alternatively,
 	 stop the paradoxical subreg stupidity in the *_operand functions
-	 in recog.c.  */
+	 in recog.cc.  */
       if (GET_CODE (x) == MEM
 	  && (GET_MODE (x) == SImode || GET_MODE (x) == HImode
 	      || GET_MODE (x) == QImode))
@@ -9226,7 +9226,7 @@ bundling (FILE *dump, int verbose, rtx_insn *prev_head_insn, rtx_insn *tail)
 	if (verbose >= 2 && dump)
 	  {
 	    /* This structure is taken from generated code of the
-	       pipeline hazard recognizer (see file insn-attrtab.c).
+	       pipeline hazard recognizer (see file insn-attrtab.cc).
 	       Please don't forget to change the structure if a new
 	       automaton is added to .md file.  */
 	    struct DFA_chip
diff --git a/gcc/config/ia64/ia64.h b/gcc/config/ia64/ia64.h
index 5615951..bd0ef35e 100644
--- a/gcc/config/ia64/ia64.h
+++ b/gcc/config/ia64/ia64.h
@@ -1335,7 +1335,7 @@ do {									\
 }
 
 /* If defined, C string expressions to be used for the `%R', `%L', `%U', and
-   `%I' options of `asm_fprintf' (see `final.c').  */
+   `%I' options of `asm_fprintf' (see `final.cc').  */
 
 #define REGISTER_PREFIX ""
 #define LOCAL_LABEL_PREFIX "."
diff --git a/gcc/config/ia64/ia64.md b/gcc/config/ia64/ia64.md
index 48e8aa6..5d1d47d 100644
--- a/gcc/config/ia64/ia64.md
+++ b/gcc/config/ia64/ia64.md
@@ -549,7 +549,7 @@
 
 ;; Define register predicate prefix.
 ;; We can generate speculative loads only for general and fp registers - this
-;; is constrained in ia64.c: ia64_speculate_insn ().
+;; is constrained in ia64.cc: ia64_speculate_insn ().
 (define_mode_attr reg_pred_prefix [(BI "gr") (QI "gr") (HI "gr") (SI "gr") (DI "grfr") (SF "grfr") (DF "grfr") (XF "fr") (TI "fr")])
 
 (define_mode_attr ld_class [(BI "ld") (QI "ld") (HI "ld") (SI "ld") (DI "ld,fld") (SF "fld,ld") (DF "fld,ld") (XF "fld") (TI "fldp")])
@@ -1420,7 +1420,7 @@
       if (width == 32 && shift == 0)
 	{
 	  /* Directly generating the mix4left instruction confuses
-	     optimize_bit_field in function.c.  Since this is performing
+	     optimize_bit_field in function.cc.  Since this is performing
 	     a useful optimization, we defer generation of the complicated
 	     mix4left RTL to the first splitting phase.  */
 	  rtx tmp = gen_reg_rtx (DImode);
diff --git a/gcc/config/ia64/predicates.md b/gcc/config/ia64/predicates.md
index 157a01c..6364d2e 100644
--- a/gcc/config/ia64/predicates.md
+++ b/gcc/config/ia64/predicates.md
@@ -653,7 +653,7 @@
 
 ;; True if OP is valid as a base register in a reg + offset address.
 ;; ??? Should I copy the flag_omit_frame_pointer and cse_not_expected
-;; checks from pa.c basereg_operand as well?  Seems to be OK without them
+;; checks from pa.cc basereg_operand as well?  Seems to be OK without them
 ;; in test runs.
 (define_predicate "basereg_operand"
   (match_operand 0 "register_operand")
diff --git a/gcc/config/ia64/sysv4.h b/gcc/config/ia64/sysv4.h
index 119c53f..045752a 100644
--- a/gcc/config/ia64/sysv4.h
+++ b/gcc/config/ia64/sysv4.h
@@ -59,10 +59,10 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    the Intel simulator.  So we must explicitly put variables in .bss
    instead.  This matters only if we care about the Intel assembler.  */
 
-/* This is asm_output_aligned_bss from varasm.c without the
+/* This is asm_output_aligned_bss from varasm.cc without the
    (*targetm.asm_out.globalize_label) call at the beginning.  */
 
-/* This is for final.c, because it is used by ASM_DECLARE_OBJECT_NAME.  */
+/* This is for final.cc, because it is used by ASM_DECLARE_OBJECT_NAME.  */
 extern int size_directive_output;
 
 #undef ASM_OUTPUT_ALIGNED_LOCAL
diff --git a/gcc/config/ia64/t-ia64 b/gcc/config/ia64/t-ia64
index fc3a9bd..3fedb7b 100644
--- a/gcc/config/ia64/t-ia64
+++ b/gcc/config/ia64/t-ia64
@@ -16,13 +16,13 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-ia64-c.o: $(srcdir)/config/ia64/ia64-c.c $(CONFIG_H) $(SYSTEM_H) \
+ia64-c.o: $(srcdir)/config/ia64/ia64-c.cc $(CONFIG_H) $(SYSTEM_H) \
     coretypes.h $(TM_H) $(TREE_H) $(CPPLIB_H) $(C_COMMON_H) $(C_PRAGMA_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/ia64/ia64-c.c
+		$(srcdir)/config/ia64/ia64-c.cc
 
 # genattrtab generates very long string literals.
 insn-attrtab.o-warn = -Wno-error
 
-ia64.o: $(srcdir)/config/ia64/ia64.c debug.h $(PARAMS_H) sel-sched.h reload.h \
+ia64.o: $(srcdir)/config/ia64/ia64.cc debug.h $(PARAMS_H) sel-sched.h reload.h \
 	$(OPTS_H) dumpfile.h $(HASH_TABLE_H)
diff --git a/gcc/config/iq2000/iq2000.h b/gcc/config/iq2000/iq2000.h
index 58a26cf..3327f14 100644
--- a/gcc/config/iq2000/iq2000.h
+++ b/gcc/config/iq2000/iq2000.h
@@ -525,7 +525,7 @@ while (0)
 
 #define FUNCTION_MODE SImode
 
-/* IQ2000 external variables defined in iq2000.c.  */
+/* IQ2000 external variables defined in iq2000.cc.  */
 
 /* Comparison type.  */
 enum cmp_type
diff --git a/gcc/config/iq2000/iq2000.md b/gcc/config/iq2000/iq2000.md
index 10f49bc..fdb346f 100644
--- a/gcc/config/iq2000/iq2000.md
+++ b/gcc/config/iq2000/iq2000.md
@@ -1495,7 +1495,7 @@
 ;;
 ;;  ....................
 
-;; calls.c now passes a third argument, make saber happy
+;; calls.cc now passes a third argument, make saber happy
 
 (define_expand "call"
   [(parallel [(call (match_operand 0 "memory_operand" "m")
@@ -1565,7 +1565,7 @@
   [(set_attr "type"	"call")
    (set_attr "mode"	"none")])
 
-;; calls.c now passes a fourth argument, make saber happy
+;; calls.cc now passes a fourth argument, make saber happy
 
 (define_expand "call_value"
   [(parallel [(set (match_operand 0 "register_operand" "=d")
diff --git a/gcc/config/linux.h b/gcc/config/linux.h
index f394404..2e888e3 100644
--- a/gcc/config/linux.h
+++ b/gcc/config/linux.h
@@ -126,7 +126,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define TARGET_HAS_BIONIC (OPTION_BIONIC)
 
 /* musl avoids problematic includes by rearranging the include directories.
- * Unfortunately, this is mostly duplicated from cppdefault.c */
+ * Unfortunately, this is mostly duplicated from cppdefault.cc */
 #if DEFAULT_LIBC == LIBC_MUSL
 #define INCLUDE_DEFAULTS_MUSL_GPP			\
     { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1,		\
@@ -200,7 +200,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #if (DEFAULT_LIBC == LIBC_UCLIBC) && defined (SINGLE_LIBC) /* uClinux */
 /* This is a *uclinux* target.  We don't define below macros to normal linux
    versions, because doing so would require *uclinux* targets to include
-   linux.c, linux-protos.h, linux.opt, etc.  We could, alternatively, add
+   linux.cc, linux-protos.h, linux.opt, etc.  We could, alternatively, add
    these files to *uclinux* targets, but that would only pollute option list
    (add -mglibc, etc.) without adding any useful support.  */
 
diff --git a/gcc/config/m32c/m32c.cc b/gcc/config/m32c/m32c.cc
index a004790..11ca9a4 100644
--- a/gcc/config/m32c/m32c.cc
+++ b/gcc/config/m32c/m32c.cc
@@ -4044,7 +4044,7 @@ m32c_function_needs_enter (void)
 /* Mark all the subexpressions of the PARALLEL rtx PAR as
    frame-related.  Return PAR.
 
-   dwarf2out.c:dwarf2out_frame_debug_expr ignores sub-expressions of a
+   dwarf2out.cc:dwarf2out_frame_debug_expr ignores sub-expressions of a
    PARALLEL rtx other than the first if they do not have the
    FRAME_RELATED flag set on them.  So this function is handy for
    marking up 'enter' instructions.  */
diff --git a/gcc/config/m32c/m32c.h b/gcc/config/m32c/m32c.h
index c419cf3..af99103 100644
--- a/gcc/config/m32c/m32c.h
+++ b/gcc/config/m32c/m32c.h
@@ -522,7 +522,7 @@ typedef struct m32c_cumulative_args
 #define MAX_REGS_PER_ADDRESS 1
 
 /* This is passed to the macros below, so that they can be implemented
-   in m32c.c.  */
+   in m32c.cc.  */
 #ifdef REG_OK_STRICT
 #define REG_OK_STRICT_V 1
 #else
diff --git a/gcc/config/m32c/t-m32c b/gcc/config/m32c/t-m32c
index 22995fd..8702608 100644
--- a/gcc/config/m32c/t-m32c
+++ b/gcc/config/m32c/t-m32c
@@ -31,7 +31,7 @@ md : $(MD_FILES:%=$(srcdir)/config/m32c/%.md) $(srcdir)/config/m32c/t-m32c
 	  echo "(include \"$(srcdir)/config/m32c/$$md.md\")"; \
 	done > md
 
-m32c-pragma.o: $(srcdir)/config/m32c/m32c-pragma.c $(RTL_H) $(TREE_H) $(CONFIG_H) $(TM_H)
+m32c-pragma.o: $(srcdir)/config/m32c/m32c-pragma.cc $(RTL_H) $(TREE_H) $(CONFIG_H) $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
 # We support four CPU series, but R8C and M16C share one multilib, and
diff --git a/gcc/config/m32r/m32r-protos.h b/gcc/config/m32r/m32r-protos.h
index ac6c2d0..dd07a99 100644
--- a/gcc/config/m32r/m32r-protos.h
+++ b/gcc/config/m32r/m32r-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for m32r.c functions used in the md file & elsewhere.
+/* Prototypes for m32r.cc functions used in the md file & elsewhere.
    Copyright (C) 1999-2022 Free Software Foundation, Inc.
 
    This file is part of GCC.
diff --git a/gcc/config/m32r/m32r.cc b/gcc/config/m32r/m32r.cc
index e40a8f5..bca7681 100644
--- a/gcc/config/m32r/m32r.cc
+++ b/gcc/config/m32r/m32r.cc
@@ -2098,7 +2098,7 @@ m32r_print_operand (FILE * file, rtx x, int code)
 	  fprintf (file, "@(");
 	  /* Handle possible auto-increment.  Since it is pre-increment and
 	     we have already done it, we can just use an offset of four.  */
-	  /* ??? This is taken from rs6000.c I think.  I don't think it is
+	  /* ??? This is taken from rs6000.cc I think.  I don't think it is
 	     currently necessary, but keep it around.  */
 	  if (GET_CODE (XEXP (x, 0)) == PRE_INC
 	      || GET_CODE (XEXP (x, 0)) == PRE_DEC)
diff --git a/gcc/config/m32r/m32r.h b/gcc/config/m32r/m32r.h
index 9eb964d..b96eec8 100644
--- a/gcc/config/m32r/m32r.h
+++ b/gcc/config/m32r/m32r.h
@@ -464,7 +464,7 @@ extern enum reg_class m32r_regno_reg_class[FIRST_PSEUDO_REGISTER];
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 #define REGNO_OK_FOR_BASE_P(REGNO) \
   ((REGNO) < FIRST_PSEUDO_REGISTER			\
@@ -801,7 +801,7 @@ L2:     .word STATIC
 }
 
 /* If defined, C string expressions to be used for the `%R', `%L',
-   `%U', and `%I' options of `asm_fprintf' (see `final.c').  These
+   `%U', and `%I' options of `asm_fprintf' (see `final.cc').  These
    are useful when a single `md' file must support multiple assembler
    formats.  In that case, the various `tm.h' files can define these
    macros differently.  */
diff --git a/gcc/config/m32r/m32r.md b/gcc/config/m32r/m32r.md
index 26d4af4..1eb6859 100644
--- a/gcc/config/m32r/m32r.md
+++ b/gcc/config/m32r/m32r.md
@@ -2195,7 +2195,7 @@
 )
 
 
-;; Block moves, see m32r.c for more details.
+;; Block moves, see m32r.cc for more details.
 ;; Argument 0 is the destination
 ;; Argument 1 is the source
 ;; Argument 2 is the length
diff --git a/gcc/config/m68k/m68k-isas.def b/gcc/config/m68k/m68k-isas.def
index 6cb9785..ea95792 100644
--- a/gcc/config/m68k/m68k-isas.def
+++ b/gcc/config/m68k/m68k-isas.def
@@ -17,7 +17,7 @@
    along with GCC; see the file COPYING3.  If not see
    <http://www.gnu.org/licenses/>.  */
 
-/* Define ISAs for the -march option, used both in m68k.c and to
+/* Define ISAs for the -march option, used both in m68k.cc and to
    generate m68k-tables.opt.  Before including this file, define a
    macro:
 
diff --git a/gcc/config/m68k/m68k-microarchs.def b/gcc/config/m68k/m68k-microarchs.def
index aa2a5ff..e488a93 100644
--- a/gcc/config/m68k/m68k-microarchs.def
+++ b/gcc/config/m68k/m68k-microarchs.def
@@ -18,7 +18,7 @@
    <http://www.gnu.org/licenses/>.  */
 
 /* Define microarchitectures for the -mtune option, used both in
-   m68k.c and to generate m68k-tables.opt.  Before including this
+   m68k.cc and to generate m68k-tables.opt.  Before including this
    file, define a macro:
 
    M68K_MICROARCH (NAME, DEVICE, MICROARCH, ISA, FLAGS)
diff --git a/gcc/config/m68k/m68k-protos.h b/gcc/config/m68k/m68k-protos.h
index a1458bf..3139eb8 100644
--- a/gcc/config/m68k/m68k-protos.h
+++ b/gcc/config/m68k/m68k-protos.h
@@ -63,7 +63,7 @@ extern int floating_exact_log2 (rtx);
 extern bool strict_low_part_peephole_ok (machine_mode mode,
 					 rtx_insn *first_insn, rtx target);
 
-/* Functions from m68k.c used in macros.  */
+/* Functions from m68k.cc used in macros.  */
 extern int standard_68881_constant_p (rtx);
 extern void print_operand_address (FILE *, rtx);
 extern void print_operand (FILE *, rtx, int);
@@ -85,10 +85,10 @@ extern bool m68k_movem_pattern_p (rtx, rtx, HOST_WIDE_INT, bool);
 extern const char *m68k_output_movem (rtx *, rtx, HOST_WIDE_INT, bool);
 extern bool m68k_epilogue_uses (int);
 
-/* Functions from m68k.c used in constraints.md.  */
+/* Functions from m68k.cc used in constraints.md.  */
 extern rtx m68k_unwrap_symbol (rtx, bool);
 
-/* Functions from m68k.c used in genattrtab.  */
+/* Functions from m68k.cc used in genattrtab.  */
 #ifdef HAVE_ATTR_cpu
 extern enum attr_cpu m68k_sched_cpu;
 extern enum attr_mac m68k_sched_mac;
diff --git a/gcc/config/m68k/m68k.cc b/gcc/config/m68k/m68k.cc
index 872b97a..1d5ef02 100644
--- a/gcc/config/m68k/m68k.cc
+++ b/gcc/config/m68k/m68k.cc
@@ -1,4 +1,4 @@
-/* Subroutines for insn-output.c for Motorola 68000 family.
+/* Subroutines for insn-output.cc for Motorola 68000 family.
    Copyright (C) 1987-2022 Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -2706,7 +2706,7 @@ m68k_call_tls_get_addr (rtx x, rtx eqv, enum m68k_reloc reloc)
      optimizations, sometimes cannot later fix this.  As a consequence,
      additional register may be allocated resulting in a spill.
      For reference, see args processing loops in
-     calls.c:emit_library_call_value_1.
+     calls.cc:emit_library_call_value_1.
      For testcase, see gcc.target/m68k/tls-{gd, ld}.c  */
   x = m68k_wrap_symbol (x, reloc, m68k_get_gp (), NULL_RTX);
 
@@ -6494,7 +6494,7 @@ m68k_sched_adjust_cost (rtx_insn *insn, int, rtx_insn *def_insn, int cost,
   if (sched_cfv4_bypass_data.scale == 1)
     /* Handle ColdFire V4 bypass for indexed address with 1x scale.  */
     {
-      /* haifa-sched.c: insn_cost () calls bypass_p () just before
+      /* haifa-sched.cc: insn_cost () calls bypass_p () just before
 	 targetm.sched.adjust_cost ().  Hence, we can be relatively sure
 	 that the data in sched_cfv4_bypass_data is up to date.  */
       gcc_assert (sched_cfv4_bypass_data.pro == def_insn
@@ -6517,7 +6517,7 @@ m68k_sched_adjust_cost (rtx_insn *insn, int, rtx_insn *def_insn, int cost,
      as their true dependence (default) latency is better to be set to 0
      to workaround alias analysis limitations.
      This is, in fact, a machine independent tweak, so, probably,
-     it should be moved to haifa-sched.c: insn_cost ().  */
+     it should be moved to haifa-sched.cc: insn_cost ().  */
   delay = min_insn_conflict_delay (sched_adjust_cost_state, def_insn, insn);
   if (delay > cost)
     cost = delay;
@@ -6798,7 +6798,7 @@ m68k_sched_md_init (FILE *sched_dump ATTRIBUTE_UNUSED,
     }
 
   if (sched_ib.enabled_p)
-    /* haifa-sched.c: schedule_block () calls advance_cycle () just before
+    /* haifa-sched.cc: schedule_block () calls advance_cycle () just before
        the first cycle.  Workaround that.  */
     sched_ib.filled = -2;
 }
diff --git a/gcc/config/m68k/m68k.h b/gcc/config/m68k/m68k.h
index c302121..cd353db 100644
--- a/gcc/config/m68k/m68k.h
+++ b/gcc/config/m68k/m68k.h
@@ -865,7 +865,7 @@ __transfer_from_trampoline ()					\
    || (CODE) == '$' || (CODE) == '&' || (CODE) == '/' || (CODE) == '?')
 
 
-/* See m68k.c for the m68k specific codes.  */
+/* See m68k.cc for the m68k specific codes.  */
 #define PRINT_OPERAND(FILE, X, CODE) print_operand (FILE, X, CODE)
 
 #define PRINT_OPERAND_ADDRESS(FILE, ADDR) print_operand_address (FILE, ADDR)
@@ -888,7 +888,7 @@ enum m68k_function_kind
   m68k_fk_interrupt_thread
 };
 
-/* Variables in m68k.c; see there for details.  */
+/* Variables in m68k.cc; see there for details.  */
 extern enum target_device m68k_cpu;
 extern enum uarch_type m68k_tune;
 extern enum fpu_type m68k_fpu;
diff --git a/gcc/config/m68k/m68k.md b/gcc/config/m68k/m68k.md
index e14255f..e4208cf 100644
--- a/gcc/config/m68k/m68k.md
+++ b/gcc/config/m68k/m68k.md
@@ -193,7 +193,7 @@
 (define_attr "opy" "" (const_int 1))
 
 ;; Type of the Y operand.
-;; See m68k.c: enum attr_op_type.
+;; See m68k.cc: enum attr_op_type.
 (define_attr "opy_type"
   "none,Rn,FPn,mem1,mem234,mem5,mem6,mem7,imm_q,imm_w,imm_l"
   (cond [(eq_attr "type" "ext,fbcc,ftst,neg_l,bcc,bra,bsr,clr,clr_l,ib,ignore,
@@ -204,7 +204,7 @@
 	(symbol_ref "m68k_sched_attr_opy_type (insn, 0)")))
 
 ;; Type of the X operand.
-;; See m68k.c: enum attr_op_type.
+;; See m68k.cc: enum attr_op_type.
 (define_attr "opx_type"
   "none,Rn,FPn,mem1,mem234,mem5,mem6,mem7,imm_q,imm_w,imm_l"
   (cond [(eq_attr "type" "ib,ignore,nop,rts,trap,unlk,
diff --git a/gcc/config/m68k/m68kemb.h b/gcc/config/m68k/m68kemb.h
index 1292454..ee55faf 100644
--- a/gcc/config/m68k/m68kemb.h
+++ b/gcc/config/m68k/m68kemb.h
@@ -39,7 +39,7 @@
     }						\
   while (0)
 
-/* Override the default LIB_SPEC from gcc.c.  We don't currently support
+/* Override the default LIB_SPEC from gcc.cc.  We don't currently support
    profiling, or libg.a.  */
 
 #undef  LIB_SPEC
diff --git a/gcc/config/m68k/uclinux.h b/gcc/config/m68k/uclinux.h
index 3027bf3..e438b6e 100644
--- a/gcc/config/m68k/uclinux.h
+++ b/gcc/config/m68k/uclinux.h
@@ -28,7 +28,7 @@ along with GCC; see the file COPYING3.  If not see
 #undef ENDFILE_SPEC
 #define ENDFILE_SPEC "crtend.o%s crtn.o%s"
 
-/* Override the default LIB_SPEC from gcc.c.  We don't currently support
+/* Override the default LIB_SPEC from gcc.cc.  We don't currently support
    profiling, or libg.a.  */
 #undef LIB_SPEC
 #define LIB_SPEC \
diff --git a/gcc/config/mcore/mcore-protos.h b/gcc/config/mcore/mcore-protos.h
index 1a6ffc6..52e0b7d 100644
--- a/gcc/config/mcore/mcore-protos.h
+++ b/gcc/config/mcore/mcore-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for exported functions defined in mcore.c
+/* Prototypes for exported functions defined in mcore.cc
    Copyright (C) 2000-2022 Free Software Foundation, Inc.
    Contributed by Nick Clifton (nickc@redhat.com)
 
diff --git a/gcc/config/mcore/mcore.cc b/gcc/config/mcore/mcore.cc
index 11cf500..28e7074 100644
--- a/gcc/config/mcore/mcore.cc
+++ b/gcc/config/mcore/mcore.cc
@@ -1463,7 +1463,7 @@ mcore_expand_insv (rtx operands[])
   int mask;
   rtx mreg, sreg, ereg;
 
-  /* To get width 1 insv, the test in store_bit_field() (expmed.c, line 191)
+  /* To get width 1 insv, the test in store_bit_field() (expmed.cc, line 191)
      for width==1 must be removed.  Look around line 368.  This is something
      we really want the md part to do.  */
   if (width == 1 && GET_CODE (operands[3]) == CONST_INT)
@@ -2021,7 +2021,7 @@ mcore_expand_prolog (void)
   output_stack_adjust (-1, fi.growth[growth++]);	/* Grows it.  */
 
   /* If we have a parameter passed partially in regs and partially in memory,
-     the registers will have been stored to memory already in function.c.  So
+     the registers will have been stored to memory already in function.cc.  So
      we only need to do something here for varargs functions.  */
   if (fi.arg_size != 0 && crtl->args.pretend_args_size == 0)
     {
diff --git a/gcc/config/mcore/mcore.h b/gcc/config/mcore/mcore.h
index 01e1674..c905c40 100644
--- a/gcc/config/mcore/mcore.h
+++ b/gcc/config/mcore/mcore.h
@@ -29,7 +29,7 @@
 /* Run-time Target Specification.  */
 #define TARGET_MCORE
 
-/* Get tree.c to declare a target-specific specialization of
+/* Get tree.cc to declare a target-specific specialization of
    merge_decl_attributes.  */
 #define TARGET_DLLIMPORT_DECL_ATTRIBUTES 1
 
@@ -482,7 +482,7 @@ extern const enum reg_class regno_reg_class[FIRST_PSEUDO_REGISTER];
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 #define REGNO_OK_FOR_BASE_P(REGNO)  \
   ((REGNO) < AP_REG || (unsigned) reg_renumber[(REGNO)] < AP_REG)
diff --git a/gcc/config/mcore/mcore.md b/gcc/config/mcore/mcore.md
index c977a48..ede545c 100644
--- a/gcc/config/mcore/mcore.md
+++ b/gcc/config/mcore/mcore.md
@@ -2642,7 +2642,7 @@
 
 ; note: in the following patterns, use mcore_is_dead() to ensure that the
 ; reg we may be trashing really is dead.  reload doesn't always mark
-; deaths, so mcore_is_dead() (see mcore.c) scans forward to find its death.  BRC
+; deaths, so mcore_is_dead() (see mcore.cc) scans forward to find its death.  BRC
 
 ;;; A peephole to convert the 3 instruction sequence generated by reload
 ;;; to load a FP-offset address into a 2 instruction sequence.
diff --git a/gcc/config/microblaze/microblaze-protos.h b/gcc/config/microblaze/microblaze-protos.h
index 702c528..d673556 100644
--- a/gcc/config/microblaze/microblaze-protos.h
+++ b/gcc/config/microblaze/microblaze-protos.h
@@ -61,7 +61,7 @@ extern bool microblaze_cannot_force_const_mem (machine_mode, rtx);
 extern void microblaze_eh_return (rtx op0);
 #endif  /* RTX_CODE */
 
-/* Declare functions in microblaze-c.c.  */
+/* Declare functions in microblaze-c.cc.  */
 extern void microblaze_cpp_define (struct cpp_reader *); 
 
 #endif  /* GCC_MICROBLAZE_PROTOS_H */
diff --git a/gcc/config/microblaze/microblaze.cc b/gcc/config/microblaze/microblaze.cc
index 75767d8..f32effe 100644
--- a/gcc/config/microblaze/microblaze.cc
+++ b/gcc/config/microblaze/microblaze.cc
@@ -964,7 +964,7 @@ microblaze_legitimate_pic_operand (rtx x)
 
 /* Try machine-dependent ways of modifying an illegitimate address
    to be legitimate.  If we find one, return the new, valid address.
-   This is used from only one place: `memory_address' in explow.c.
+   This is used from only one place: `memory_address' in explow.cc.
 
    OLDX is the address as it was before break_out_memory_refs was
    called.  In some cases it is useful to look at this to decide what
@@ -2767,7 +2767,7 @@ microblaze_function_prologue (FILE * file)
   const char *fnname;
   long fsiz = current_frame_info.total_size;
 
-  /* Get the function name the same way that toplev.c does before calling
+  /* Get the function name the same way that toplev.cc does before calling
      assemble_start_function.  This is needed so that the name used here
      exactly matches the name used in ASM_DECLARE_FUNCTION_NAME.  */
   fnname = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
@@ -3069,7 +3069,7 @@ microblaze_function_epilogue (FILE *file)
 {
   const char *fnname;
 
-  /* Get the function name the same way that toplev.c does before calling
+  /* Get the function name the same way that toplev.cc does before calling
      assemble_start_function.  This is needed so that the name used here
      exactly matches the name used in ASM_DECLARE_FUNCTION_NAME.  */
   fnname = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
@@ -3271,7 +3271,7 @@ microblaze_select_section (tree decl, int reloc, unsigned HOST_WIDE_INT align)
 /*
   Encode info about sections into the RTL based on a symbol's declaration.
   The default definition of this hook, default_encode_section_info in 
-  `varasm.c', sets a number of commonly-useful bits in SYMBOL_REF_FLAGS. */
+  `varasm.cc', sets a number of commonly-useful bits in SYMBOL_REF_FLAGS. */
 
 static void
 microblaze_encode_section_info (tree decl, rtx rtl, int first)
@@ -3357,7 +3357,7 @@ microblaze_asm_output_mi_thunk (FILE *file, tree thunk_fndecl ATTRIBUTE_UNUSED,
   emit_insn (gen_indirect_jump (temp2));
 
   /* Run just enough of rest_of_compilation.  This sequence was
-     "borrowed" from rs6000.c.  */
+     "borrowed" from rs6000.cc.  */
   insn = get_insns ();
   shorten_branches (insn);
   assemble_start_function (thunk_fndecl, fnname);
@@ -3511,7 +3511,7 @@ microblaze_eh_return (rtx op0)
 
 /* Queue an .ident string in the queue of top-level asm statements.
    If the string size is below the threshold, put it into .sdata2.
-   If the front-end is done, we must be being called from toplev.c.
+   If the front-end is done, we must be being called from toplev.cc.
    In that case, do nothing.  */
 void 
 microblaze_asm_output_ident (const char *string)
diff --git a/gcc/config/microblaze/microblaze.h b/gcc/config/microblaze/microblaze.h
index 01737df..d28bc76 100644
--- a/gcc/config/microblaze/microblaze.h
+++ b/gcc/config/microblaze/microblaze.h
@@ -21,7 +21,7 @@
 
 /* Standard GCC variables that we reference.  */
 
-/* MicroBlaze external variables defined in microblaze.c.  */
+/* MicroBlaze external variables defined in microblaze.cc.  */
 
 /* Which pipeline to schedule for.  */
 enum pipeline_type
diff --git a/gcc/config/microblaze/microblaze.md b/gcc/config/microblaze/microblaze.md
index 7a6146c..0765ff9 100644
--- a/gcc/config/microblaze/microblaze.md
+++ b/gcc/config/microblaze/microblaze.md
@@ -1138,7 +1138,7 @@
   (set_attr "mode"	"QI")
   (set_attr "length"	"4,4,8,4,8,4,8")])
 
-;; Block moves, see microblaze.c for more details.
+;; Block moves, see microblaze.cc for more details.
 ;; Argument 0 is the destination
 ;; Argument 1 is the source
 ;; Argument 2 is the length
@@ -2147,7 +2147,7 @@
   (set_attr "mode"	"none")
   (set_attr "length"	"4")])
 
-;; calls.c now passes a fourth argument, make saber happy
+;; calls.cc now passes a fourth argument, make saber happy
 
 (define_expand "call_value"
   [(parallel [(set (match_operand 0 "register_operand" "=d")
diff --git a/gcc/config/microblaze/t-microblaze b/gcc/config/microblaze/t-microblaze
index 41fa9a9..7e2fc5d 100644
--- a/gcc/config/microblaze/t-microblaze
+++ b/gcc/config/microblaze/t-microblaze
@@ -5,8 +5,8 @@ MULTILIB_EXCEPTIONS += *mxl-barrel-shift/mxl-multiply-high/mlittle-endian
 MULTILIB_EXCEPTIONS += mxl-multiply-high/mlittle-endian
 
 # Extra files
-microblaze-c.o: $(srcdir)/config/microblaze/microblaze-c.c \
+microblaze-c.o: $(srcdir)/config/microblaze/microblaze-c.cc \
     $(srcdir)/config/microblaze/microblaze-protos.h \
     $(CONFIG_H) $(SYSTEM_H) $(CPPLIB_H) $(TM_P_H) $(TREE_H) errors.h $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-	$(srcdir)/config/microblaze/microblaze-c.c
+	$(srcdir)/config/microblaze/microblaze-c.cc
diff --git a/gcc/config/mips/driver-native.cc b/gcc/config/mips/driver-native.cc
index 7cfa381..47627f8 100644
--- a/gcc/config/mips/driver-native.cc
+++ b/gcc/config/mips/driver-native.cc
@@ -24,7 +24,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "coretypes.h"
 #include "tm.h"
 
-/* This will be called by the spec parser in gcc.c when it sees
+/* This will be called by the spec parser in gcc.cc when it sees
    a %:local_cpu_detect(args) construct.  Currently it will be called
    with either "arch" or "tune" as argument depending on if -march=native
    or -mtune=native is to be substituted.
diff --git a/gcc/config/mips/loongson2ef.md b/gcc/config/mips/loongson2ef.md
index 0038dde..793f208 100644
--- a/gcc/config/mips/loongson2ef.md
+++ b/gcc/config/mips/loongson2ef.md
@@ -96,7 +96,7 @@
 
 ;; The following 4 instructions each subscribe one of
 ;; ls2_[f]alu{1,2}_turn_enabled units according to this attribute.
-;; These instructions are used in mips.c: sched_ls2_dfa_post_advance_cycle.
+;; These instructions are used in mips.cc: sched_ls2_dfa_post_advance_cycle.
 
 (define_attr "ls2_turn_type" "alu1,alu2,falu1,falu2,unknown,atomic,syncloop"
   (const_string "unknown"))
diff --git a/gcc/config/mips/mips-protos.h b/gcc/config/mips/mips-protos.h
index 877de78..9d0f4d9 100644
--- a/gcc/config/mips/mips-protos.h
+++ b/gcc/config/mips/mips-protos.h
@@ -388,7 +388,7 @@ extern void mips_register_frame_header_opt (void);
 extern void mips_expand_vec_cond_expr (machine_mode, machine_mode, rtx *);
 extern void mips_expand_vec_cmp_expr (rtx *);
 
-/* Routines implemented in mips-d.c  */
+/* Routines implemented in mips-d.cc  */
 extern void mips_d_target_versions (void);
 extern void mips_d_register_target_info (void);
 
diff --git a/gcc/config/mips/mips.cc b/gcc/config/mips/mips.cc
index 8c7d669..6c0da2b 100644
--- a/gcc/config/mips/mips.cc
+++ b/gcc/config/mips/mips.cc
@@ -4456,7 +4456,7 @@ mips_rtx_costs (rtx x, machine_mode mode, int outer_code,
 	  /* It is our responsibility to make division by a power of 2
 	     as cheap as 2 register additions if we want the division
 	     expanders to be used for such operations; see the setting
-	     of sdiv_pow2_cheap in optabs.c.  Using (D)DIV for MIPS16
+	     of sdiv_pow2_cheap in optabs.cc.  Using (D)DIV for MIPS16
 	     should always produce shorter code than using
 	     expand_sdiv2_pow2.  */
 	  if (TARGET_MIPS16
@@ -9466,7 +9466,7 @@ mips_output_filename (FILE *stream, const char *name)
       output_quoted_string (stream, name);
       putc ('\n', stream);
     }
-  /* If we are emitting stabs, let dbxout.c handle this (except for
+  /* If we are emitting stabs, let dbxout.cc handle this (except for
      the mips_output_filename_first_time case).  */
   else if (write_symbols == DBX_DEBUG)
     return;
@@ -11799,7 +11799,7 @@ mips_output_function_prologue (FILE *file)
       && crtl->args.info.fp_code != 0)
     mips16_build_function_stub ();
 
-  /* Get the function name the same way that toplev.c does before calling
+  /* Get the function name the same way that toplev.cc does before calling
      assemble_start_function.  This is needed so that the name used here
      exactly matches the name used in ASM_DECLARE_FUNCTION_NAME.  */
   fnname = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
@@ -11897,7 +11897,7 @@ mips_output_function_epilogue (FILE *)
       mips_pop_asm_switch (&mips_noreorder);
     }
 
-  /* Get the function name the same way that toplev.c does before calling
+  /* Get the function name the same way that toplev.cc does before calling
      assemble_start_function.  This is needed so that the name used here
      exactly matches the name used in ASM_DECLARE_FUNCTION_NAME.  */
   fnname = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
@@ -19620,7 +19620,7 @@ mips_output_mi_thunk (FILE *file, tree thunk_fndecl ATTRIBUTE_UNUSED,
     }
 
   /* Run just enough of rest_of_compilation.  This sequence was
-     "borrowed" from alpha.c.  */
+     "borrowed" from alpha.cc.  */
   insn = get_insns ();
   split_all_insns_noflow ();
   mips16_lay_out_constants (true);
diff --git a/gcc/config/mips/mips.h b/gcc/config/mips/mips.h
index 30e6e2b..bf5c1d5 100644
--- a/gcc/config/mips/mips.h
+++ b/gcc/config/mips/mips.h
@@ -30,7 +30,7 @@ along with GCC; see the file COPYING3.  If not see
 extern int target_flags_explicit;
 #endif
 
-/* MIPS external variables defined in mips.c.  */
+/* MIPS external variables defined in mips.cc.  */
 
 /* Which ABI to use.  ABI_32 (original 32, or o32), ABI_N32 (n32),
    ABI_64 (n64) are all defined by SGI.  ABI_O64 is o32 extended
diff --git a/gcc/config/mips/mips.md b/gcc/config/mips/mips.md
index cc412b1..e0f0a58 100644
--- a/gcc/config/mips/mips.md
+++ b/gcc/config/mips/mips.md
@@ -5657,7 +5657,7 @@
   "cache\t0x14,0(%$)"
   [(set_attr "can_delay" "no")])
 
-;; Block moves, see mips.c for more details.
+;; Block moves, see mips.cc for more details.
 ;; Argument 0 is the destination
 ;; Argument 1 is the source
 ;; Argument 2 is the length
diff --git a/gcc/config/mips/t-mips b/gcc/config/mips/t-mips
index 9920fb4..d7a934f 100644
--- a/gcc/config/mips/t-mips
+++ b/gcc/config/mips/t-mips
@@ -21,10 +21,10 @@ $(srcdir)/config/mips/mips-tables.opt: $(srcdir)/config/mips/genopt.sh \
 	$(SHELL) $(srcdir)/config/mips/genopt.sh $(srcdir)/config/mips > \
 		$(srcdir)/config/mips/mips-tables.opt
 
-frame-header-opt.o: $(srcdir)/config/mips/frame-header-opt.c
+frame-header-opt.o: $(srcdir)/config/mips/frame-header-opt.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-mips-d.o: $(srcdir)/config/mips/mips-d.c
+mips-d.o: $(srcdir)/config/mips/mips-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/mips/x-native b/gcc/config/mips/x-native
index 5e31121..cf28636 100644
--- a/gcc/config/mips/x-native
+++ b/gcc/config/mips/x-native
@@ -1,3 +1,3 @@
-driver-native.o : $(srcdir)/config/mips/driver-native.c \
+driver-native.o : $(srcdir)/config/mips/driver-native.cc \
   $(CONFIG_H) $(SYSTEM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/mmix/mmix-protos.h b/gcc/config/mmix/mmix-protos.h
index 9ee84a2..d9a40d3 100644
--- a/gcc/config/mmix/mmix-protos.h
+++ b/gcc/config/mmix/mmix-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for exported functions defined in mmix.c
+/* Prototypes for exported functions defined in mmix.cc
    Copyright (C) 2000-2022 Free Software Foundation, Inc.
    Contributed by Hans-Peter Nilsson (hp@bitrange.com)
 
diff --git a/gcc/config/mmix/mmix.cc b/gcc/config/mmix/mmix.cc
index 6e2bccd..18053d4 100644
--- a/gcc/config/mmix/mmix.cc
+++ b/gcc/config/mmix/mmix.cc
@@ -332,7 +332,7 @@ mmix_option_override (void)
      mixed-syntax assembly output already looks too ugly for the
      intent of being readable, and the resulting mix certainly fails
      the intent of being compatible with mmixal.  See
-     varasm.c:default_file_start for this triple.  See also
+     varasm.cc:default_file_start for this triple.  See also
      mmix_assemble_integer.  */
   if (flag_verbose_asm || flag_debug_asm || flag_dump_rtl_in_asm)
     {
@@ -1966,7 +1966,7 @@ mmix_dbx_register_number (unsigned regno)
    Now the MMIX port's own functions.  First the exported ones.  */
 
 /* Wrapper for get_hard_reg_initial_val since integrate.h isn't included
-   from insn-emit.c.  */
+   from insn-emit.cc.  */
 
 rtx
 mmix_get_hard_reg_initial_val (machine_mode mode, int regno)
@@ -2195,7 +2195,7 @@ mmix_expand_prologue (void)
 	 the register stack at landing pads.  FIXME: It's a kludge because
 	 we can't describe the effect of the PUSHJ and PUSHGO insns on the
 	 register stack at the moment.  Best thing would be to handle it
-	 like stack-pointer offsets.  Better: some hook into dwarf2out.c
+	 like stack-pointer offsets.  Better: some hook into dwarf2out.cc
 	 to produce DW_CFA_expression:s that specify the increment of rO,
 	 and unwind it at eh_return (preferred) or at the landing pad.
 	 Then saves to $0..$G-1 could be specified through that register.  */
diff --git a/gcc/config/mmix/mmix.h b/gcc/config/mmix/mmix.h
index 1e3018c..0fc45db 100644
--- a/gcc/config/mmix/mmix.h
+++ b/gcc/config/mmix/mmix.h
@@ -529,7 +529,7 @@ typedef struct { int regs; int lib; } CUMULATIVE_ARGS;
 
 /* Node: Function Entry */
 
-/* See mmix.c for TARGET_ASM_FUNCTION_PROLOGUE and
+/* See mmix.cc for TARGET_ASM_FUNCTION_PROLOGUE and
    TARGET_ASM_FUNCTION_EPILOGUE.  */
 
 /* We need to say that the epilogue uses the return address, so the
diff --git a/gcc/config/mmix/mmix.md b/gcc/config/mmix/mmix.md
index 18e2164..8bafb1a 100644
--- a/gcc/config/mmix/mmix.md
+++ b/gcc/config/mmix/mmix.md
@@ -904,7 +904,7 @@ DIVU %1,%1,%2\;GET %0,:rR\;NEGU %2,0,%0\;CSNN %0,$255,%2")
   ""
   "
 {
-  /* The head comment of optabs.c:can_compare_p says we're required to
+  /* The head comment of optabs.cc:can_compare_p says we're required to
      implement this, so we have to clean up the mess here.  */
   if (GET_CODE (operands[0]) == LE || GET_CODE (operands[0]) == GE)
     {
@@ -1036,7 +1036,7 @@ DIVU %1,%1,%2\;GET %0,:rR\;NEGU %2,0,%0\;CSNN %0,$255,%2")
 ;; Don't use 'p' here.  A 'p' must stand first in constraints, or reload
 ;; messes up, not registering the address for reload.  Several C++
 ;; testcases, including g++.brendan/crash40.C.  FIXME: This is arguably a
-;; bug in gcc.  Note line ~2612 in reload.c, that does things on the
+;; bug in gcc.  Note line ~2612 in reload.cc, that does things on the
 ;; condition <<else if (constraints[i][0] == 'p')>> and the comment on
 ;; ~3017 that says:
 ;; <<   case 'p':
diff --git a/gcc/config/mmix/predicates.md b/gcc/config/mmix/predicates.md
index 40c6317..96b214c 100644
--- a/gcc/config/mmix/predicates.md
+++ b/gcc/config/mmix/predicates.md
@@ -49,7 +49,7 @@
 })
 
 ;; Like comparison_operator, but only true if this comparison operator is
-;; applied to a valid mode.  Needed to avoid jump.c generating invalid
+;; applied to a valid mode.  Needed to avoid jump.cc generating invalid
 ;; code with -ffast-math (gcc.dg/20001228-1.c).
 
 (define_predicate "mmix_comparison_operator"
diff --git a/gcc/config/mn10300/mn10300.cc b/gcc/config/mn10300/mn10300.cc
index d375c70..2a58dd9 100644
--- a/gcc/config/mn10300/mn10300.cc
+++ b/gcc/config/mn10300/mn10300.cc
@@ -1,4 +1,4 @@
-/* Subroutines for insn-output.c for Matsushita MN10300 series
+/* Subroutines for insn-output.cc for Matsushita MN10300 series
    Copyright (C) 1996-2022 Free Software Foundation, Inc.
    Contributed by Jeff Law (law@cygnus.com).
 
@@ -1787,7 +1787,7 @@ mn10300_symbolic_operand (rtx op,
 
 /* Try machine dependent ways of modifying an illegitimate address
    to be legitimate.  If we find one, return the new valid address.
-   This macro is used in only one place: `memory_address' in explow.c.
+   This macro is used in only one place: `memory_address' in explow.cc.
 
    OLDX is the address as it was before break_out_memory_refs was called.
    In some cases it is useful to look at this to decide what needs to be done.
@@ -1928,7 +1928,7 @@ mn10300_legitimate_pic_operand_p (rtx x)
 
    Note it is still possible to use reg+reg addressing modes,
    it's just much more difficult.  For a discussion of a possible
-   workaround and solution, see the comments in pa.c before the
+   workaround and solution, see the comments in pa.cc before the
    function record_unscaled_index_insn_codes.  */
 
 static bool
diff --git a/gcc/config/mn10300/mn10300.h b/gcc/config/mn10300/mn10300.h
index 815d50c..bc57f4b 100644
--- a/gcc/config/mn10300/mn10300.h
+++ b/gcc/config/mn10300/mn10300.h
@@ -318,7 +318,7 @@ enum reg_class
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 
 #ifndef REG_OK_STRICT
@@ -546,7 +546,7 @@ do {									     \
 
 #define NO_FUNCTION_CSE 1
 
-/* According expr.c, a value of around 6 should minimize code size, and
+/* According expr.cc, a value of around 6 should minimize code size, and
    for the MN10300 series, that's our primary concern.  */
 #define MOVE_RATIO(speed) 6
 
@@ -624,7 +624,7 @@ do {									     \
 }
 
 /* Print an instruction operand X on file FILE.
-   look in mn10300.c for details */
+   look in mn10300.cc for details */
 
 #define PRINT_OPERAND(FILE, X, CODE) \
   mn10300_print_operand (FILE, X, CODE)
diff --git a/gcc/config/moxie/moxie-protos.h b/gcc/config/moxie/moxie-protos.h
index 288d68f..0a6c6cf 100644
--- a/gcc/config/moxie/moxie-protos.h
+++ b/gcc/config/moxie/moxie-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for moxie.c functions used in the md file & elsewhere.
+/* Prototypes for moxie.cc functions used in the md file & elsewhere.
    Copyright (C) 2009-2022 Free Software Foundation, Inc.
 
 This file is part of GCC.
diff --git a/gcc/config/moxie/uclinux.h b/gcc/config/moxie/uclinux.h
index 3b3fdc6..b84d532 100644
--- a/gcc/config/moxie/uclinux.h
+++ b/gcc/config/moxie/uclinux.h
@@ -33,7 +33,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #undef TARGET_LIBC_HAS_FUNCTION
 #define TARGET_LIBC_HAS_FUNCTION no_c99_libc_has_function
 
-/* Like the definition in gcc.c, but for purposes of uClinux, every link is
+/* Like the definition in gcc.cc, but for purposes of uClinux, every link is
    static.  */
 #define MFWRAP_SPEC " %{fmudflap|fmudflapth: \
  --wrap=malloc --wrap=free --wrap=calloc --wrap=realloc\
diff --git a/gcc/config/msp430/msp430-devices.cc b/gcc/config/msp430/msp430-devices.cc
index 85a2ad1..95288e5 100644
--- a/gcc/config/msp430/msp430-devices.cc
+++ b/gcc/config/msp430/msp430-devices.cc
@@ -98,7 +98,7 @@ extract_devices_dir_from_exec_prefix (char **devices_loc)
   char *gcc_exec_prefix = *devices_loc;
   int len = strlen (gcc_exec_prefix);
 
-  /* Copied from gcc.c.  */
+  /* Copied from gcc.cc.  */
   if (len > (int) sizeof ("/lib/gcc/") - 1
       && (IS_DIR_SEPARATOR (gcc_exec_prefix[len-1])))
     {
diff --git a/gcc/config/msp430/msp430.cc b/gcc/config/msp430/msp430.cc
index 136f014..18673ff 100644
--- a/gcc/config/msp430/msp430.cc
+++ b/gcc/config/msp430/msp430.cc
@@ -848,7 +848,7 @@ msp430_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
   if (boundary > align
       && !integer_zerop (TYPE_SIZE (type)))
     {
-      /* FIXME: This is where this function diverts from targhooks.c:
+      /* FIXME: This is where this function diverts from targhooks.cc:
 	 std_gimplify_va_arg_expr().  It works, but I do not know why...  */
       if (! POINTER_TYPE_P (type))
 	{
@@ -4426,7 +4426,7 @@ msp430_incoming_return_addr_rtx (void)
 
 /* If the path to the MSP430-GCC support files has been found by examining
    an environment variable (see msp430_check_env_var_for_devices in
-   msp430-devices.c), or -mdevices-csv-loc=, register this path as an include
+   msp430-devices.cc), or -mdevices-csv-loc=, register this path as an include
    directory so the user can #include msp430.h without needing to specify the
    path to the support files with -I.  */
 void
diff --git a/gcc/config/msp430/msp430.h b/gcc/config/msp430/msp430.h
index 8464784..3966765 100644
--- a/gcc/config/msp430/msp430.h
+++ b/gcc/config/msp430/msp430.h
@@ -103,7 +103,7 @@ extern const char * msp430_check_path_for_devices (int, const char **);
 extern const char *msp430_propagate_region_opt (int, const char **);
 extern const char *msp430_get_linker_devices_include_path (int, const char **);
 
-/* There must be a trailing comma after the last item, see gcc.c
+/* There must be a trailing comma after the last item, see gcc.cc
    "static_spec_functions".  */
 # define EXTRA_SPEC_FUNCTIONS				\
   { "msp430_hwmult_lib", msp430_select_hwmult_lib },	\
@@ -128,7 +128,7 @@ extern const char *msp430_get_linker_devices_include_path (int, const char **);
    reason that a spec function is used.  There are so many possible
    values of FOO that a table is used to look up the name and map
    it to a hardware multiply library.  This table (in device-msp430.c)
-   must be kept in sync with the same table in msp430.c.  */
+   must be kept in sync with the same table in msp430.cc.  */
 #undef  LIB_SPEC
 #define LIB_SPEC "					\
 --start-group						\
diff --git a/gcc/config/msp430/t-msp430 b/gcc/config/msp430/t-msp430
index 94720d8..bc7df12 100644
--- a/gcc/config/msp430/t-msp430
+++ b/gcc/config/msp430/t-msp430
@@ -18,11 +18,11 @@
 # License along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-driver-msp430.o: $(srcdir)/config/msp430/driver-msp430.c \
+driver-msp430.o: $(srcdir)/config/msp430/driver-msp430.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
-msp430-devices.o: $(srcdir)/config/msp430/msp430-devices.c \
+msp430-devices.o: $(srcdir)/config/msp430/msp430-devices.cc \
 	$(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) -DTARGET_SUBDIR=$(target_subdir) $(INCLUDES) $<
 
@@ -49,5 +49,5 @@ MULTILIB_REQUIRED += mlarge/mdata-region=none/fno-exceptions
 
 MULTILIB_EXTRA_OPTS =
 
-msp430-c.o: $(srcdir)/config/msp430/msp430-c.c $(RTL_H) $(TREE_H) $(CONFIG_H) $(TM_H)
+msp430-c.o: $(srcdir)/config/msp430/msp430-c.cc $(RTL_H) $(TREE_H) $(CONFIG_H) $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/nds32/nds32-cost.cc b/gcc/config/nds32/nds32-cost.cc
index eccbbe5..af6ae07 100644
--- a/gcc/config/nds32/nds32-cost.cc
+++ b/gcc/config/nds32/nds32-cost.cc
@@ -66,7 +66,7 @@ nds32_rtx_costs_speed_prefer (rtx x ATTRIBUTE_UNUSED,
   switch (code)
     {
     case USE:
-      /* Used in combine.c as a marker.  */
+      /* Used in combine.cc as a marker.  */
       *total = 0;
       return true;
 
@@ -418,7 +418,7 @@ nds32_rtx_costs_size_prefer (rtx x,
       return false;
 
     case USE:
-      /* Used in combine.c as a marker.  */
+      /* Used in combine.cc as a marker.  */
       *total = 0;
       break;
 
@@ -506,7 +506,7 @@ nds32_init_rtx_costs (void)
 /* This target hook describes the relative costs of RTL expressions.
    Return 'true' when all subexpressions of x have been processed.
    Return 'false' to sum the costs of sub-rtx, plus cost of this operation.
-   Refer to gcc/rtlanal.c for more information.  */
+   Refer to gcc/rtlanal.cc for more information.  */
 bool
 nds32_rtx_costs_impl (rtx x,
 		      machine_mode mode ATTRIBUTE_UNUSED,
diff --git a/gcc/config/nds32/nds32-doubleword.md b/gcc/config/nds32/nds32-doubleword.md
index 3ce9c6c..19d4be3 100644
--- a/gcc/config/nds32/nds32-doubleword.md
+++ b/gcc/config/nds32/nds32-doubleword.md
@@ -150,7 +150,7 @@
   /* Construct highpart rtx.  */
   /* Note that operands[1] can be VOIDmode constant,
      so we need to use gen_highpart_mode().
-     Refer to gcc/emit-rtl.c for more information.  */
+     Refer to gcc/emit-rtl.cc for more information.  */
   operands[4] = gen_highpart (SImode, operands[0]);
   operands[5] = gen_highpart_mode (SImode,
 				   GET_MODE (operands[0]), operands[1]);
diff --git a/gcc/config/nds32/nds32.cc b/gcc/config/nds32/nds32.cc
index 7cf060b..aab02ff 100644
--- a/gcc/config/nds32/nds32.cc
+++ b/gcc/config/nds32/nds32.cc
@@ -3052,7 +3052,7 @@ nds32_memory_move_cost (machine_mode mode ATTRIBUTE_UNUSED,
 /* This target hook describes the relative costs of RTL expressions.
    Return 'true' when all subexpressions of x have been processed.
    Return 'false' to sum the costs of sub-rtx, plus cost of this operation.
-   Refer to gcc/rtlanal.c for more information.  */
+   Refer to gcc/rtlanal.cc for more information.  */
 static bool
 nds32_rtx_costs (rtx x,
 		 machine_mode mode,
@@ -4219,7 +4219,7 @@ nds32_init_builtins (void)
 static tree
 nds32_builtin_decl (unsigned code, bool initialize_p)
 {
-  /* Implement in nds32-intrinsic.c.  */
+  /* Implement in nds32-intrinsic.cc.  */
   return nds32_builtin_decl_impl (code, initialize_p);
 }
 
diff --git a/gcc/config/nds32/nds32.h b/gcc/config/nds32/nds32.h
index d5662c1..18ef8ae 100644
--- a/gcc/config/nds32/nds32.h
+++ b/gcc/config/nds32/nds32.h
@@ -22,7 +22,7 @@
 /* ------------------------------------------------------------------------ */
 
 /* The following are auxiliary macros or structure declarations
-   that are used all over the nds32.c and nds32.h.  */
+   that are used all over the nds32.cc and nds32.h.  */
 
 #define ADJUST_INSN_LENGTH(INSN, LENGTH) \
   (LENGTH = nds32_adjust_insn_length (INSN, LENGTH))
@@ -147,7 +147,7 @@ enum nds32_16bit_address_type
 
 /* Determine whether we would like to have code generation strictly aligned.
    We set it strictly aligned when -malways-align is enabled.
-   Check gcc/common/config/nds32/nds32-common.c for the optimizations that
+   Check gcc/common/config/nds32/nds32-common.cc for the optimizations that
    apply -malways-align.  */
 #define NDS32_ALIGN_P() (TARGET_ALWAYS_ALIGN)
 
@@ -342,7 +342,7 @@ typedef struct
    0 for reset handler,
    1-8 for exception handler,
    and 9-72 for interrupt handler.
-   We use an array, which is defined in nds32.c, to record
+   We use an array, which is defined in nds32.cc, to record
    essential information for each vector.  */
 #define NDS32_N_ISR_VECTORS 73
 
@@ -373,7 +373,7 @@ enum nds32_isr_nested_type
 
 /* Define structure to record isr information.
    The isr vector array 'isr_vectors[]' with this structure
-   is defined in nds32.c.  */
+   is defined in nds32.cc.  */
 struct nds32_isr_info
 {
   /* The field to identify isr category.
@@ -1411,7 +1411,7 @@ enum reg_class
 	  chain_value
 	  nested function address
 
-   Please check nds32.c implementation for more information.  */
+   Please check nds32.cc implementation for more information.  */
 #define TRAMPOLINE_SIZE 24
 
 /* Because all instructions/data in trampoline template are 4-byte size,
diff --git a/gcc/config/nds32/predicates.md b/gcc/config/nds32/predicates.md
index 954573f..e09ff02 100644
--- a/gcc/config/nds32/predicates.md
+++ b/gcc/config/nds32/predicates.md
@@ -215,7 +215,7 @@
   (match_code "parallel")
 {
   /* To verify 'load' operation, pass 'true' for the second argument.
-     See the implementation in nds32.c for details.  */
+     See the implementation in nds32.cc for details.  */
   return nds32_valid_multiple_load_store_p (op, true, false);
 })
 
@@ -224,7 +224,7 @@
 {
   /* To verify 'load' operation, pass 'true' for the second argument.
      to verify 'update address' operation, pass 'true' for the third argument
-     See the implementation in nds32.c for details.  */
+     See the implementation in nds32.cc for details.  */
   return nds32_valid_multiple_load_store_p (op, true, true);
 })
 
@@ -232,7 +232,7 @@
   (match_code "parallel")
 {
   /* To verify 'store' operation, pass 'false' for the second argument.
-     See the implementation in nds32.c for details.  */
+     See the implementation in nds32.cc for details.  */
   return nds32_valid_multiple_load_store_p (op, false, false);
 })
 
@@ -241,7 +241,7 @@
 {
   /* To verify 'store' operation, pass 'false' for the second argument,
      to verify 'update address' operation, pass 'true' for the third argument
-     See the implementation in nds32.c for details.  */
+     See the implementation in nds32.cc for details.  */
   return nds32_valid_multiple_load_store_p (op, false, true);
 })
 
@@ -249,7 +249,7 @@
   (match_code "parallel")
 {
   /* To verify 'push' operation, pass 'true' for the second argument.
-     See the implementation in nds32-predicates.c for details.  */
+     See the implementation in nds32-predicates.cc for details.  */
   return nds32_valid_stack_push_pop_p (op, true);
 })
 
@@ -257,7 +257,7 @@
   (match_code "parallel")
 {
   /* To verify 'pop' operation, pass 'false' for the second argument.
-     See the implementation in nds32-predicates.c for details.  */
+     See the implementation in nds32-predicates.cc for details.  */
   return nds32_valid_stack_push_pop_p (op, false);
 })
 
diff --git a/gcc/config/nds32/t-nds32 b/gcc/config/nds32/t-nds32
index 1eb9de6..3833f3d 100644
--- a/gcc/config/nds32/t-nds32
+++ b/gcc/config/nds32/t-nds32
@@ -19,7 +19,7 @@
 # <http://www.gnu.org/licenses/>.
 
 
-nds32-md-auxiliary.o: $(srcdir)/config/nds32/nds32-md-auxiliary.c \
+nds32-md-auxiliary.o: $(srcdir)/config/nds32/nds32-md-auxiliary.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -29,9 +29,9 @@ nds32-md-auxiliary.o: $(srcdir)/config/nds32/nds32-md-auxiliary.c \
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-md-auxiliary.c
+		$(srcdir)/config/nds32/nds32-md-auxiliary.cc
 
-nds32-memory-manipulation.o: $(srcdir)/config/nds32/nds32-memory-manipulation.c \
+nds32-memory-manipulation.o: $(srcdir)/config/nds32/nds32-memory-manipulation.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -41,9 +41,9 @@ nds32-memory-manipulation.o: $(srcdir)/config/nds32/nds32-memory-manipulation.c
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-memory-manipulation.c
+		$(srcdir)/config/nds32/nds32-memory-manipulation.cc
 
-nds32-predicates.o: $(srcdir)/config/nds32/nds32-predicates.c \
+nds32-predicates.o: $(srcdir)/config/nds32/nds32-predicates.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -53,9 +53,9 @@ nds32-predicates.o: $(srcdir)/config/nds32/nds32-predicates.c \
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-predicates.c
+		$(srcdir)/config/nds32/nds32-predicates.cc
 
-nds32-intrinsic.o: $(srcdir)/config/nds32/nds32-intrinsic.c \
+nds32-intrinsic.o: $(srcdir)/config/nds32/nds32-intrinsic.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -65,10 +65,10 @@ nds32-intrinsic.o: $(srcdir)/config/nds32/nds32-intrinsic.c \
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-intrinsic.c
+		$(srcdir)/config/nds32/nds32-intrinsic.cc
 
 nds32-pipelines-auxiliary.o: \
-  $(srcdir)/config/nds32/nds32-pipelines-auxiliary.c \
+  $(srcdir)/config/nds32/nds32-pipelines-auxiliary.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -78,10 +78,10 @@ nds32-pipelines-auxiliary.o: \
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-pipelines-auxiliary.c
+		$(srcdir)/config/nds32/nds32-pipelines-auxiliary.cc
 
 nds32-isr.o: \
-  $(srcdir)/config/nds32/nds32-isr.c \
+  $(srcdir)/config/nds32/nds32-isr.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -91,10 +91,10 @@ nds32-isr.o: \
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-isr.c
+		$(srcdir)/config/nds32/nds32-isr.cc
 
 nds32-cost.o: \
-  $(srcdir)/config/nds32/nds32-cost.c \
+  $(srcdir)/config/nds32/nds32-cost.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -104,10 +104,10 @@ nds32-cost.o: \
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-cost.c
+		$(srcdir)/config/nds32/nds32-cost.cc
 
 nds32-fp-as-gp.o: \
-  $(srcdir)/config/nds32/nds32-fp-as-gp.c \
+  $(srcdir)/config/nds32/nds32-fp-as-gp.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -117,10 +117,10 @@ nds32-fp-as-gp.o: \
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-fp-as-gp.c
+		$(srcdir)/config/nds32/nds32-fp-as-gp.cc
 
 nds32-relax-opt.o: \
-  $(srcdir)/config/nds32/nds32-relax-opt.c \
+  $(srcdir)/config/nds32/nds32-relax-opt.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -130,10 +130,10 @@ nds32-relax-opt.o: \
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-relax-opt.c
+		$(srcdir)/config/nds32/nds32-relax-opt.cc
 
 nds32-utils.o: \
-  $(srcdir)/config/nds32/nds32-utils.c \
+  $(srcdir)/config/nds32/nds32-utils.cc \
   $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
   $(RTL_H) $(TREE_H) $(HASH_TABLE_H) $(OBSTACK_H) $(REGS_H) hard-reg-set.h \
   insn-config.h conditions.h output.h dumpfile.h \
@@ -143,4 +143,4 @@ nds32-utils.o: \
   $(TARGET_H) $(TARGET_DEF_H) debug.h langhooks.h $(DF_H) \
   intl.h libfuncs.h $(PARAMS_H) $(OPTS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/nds32/nds32-utils.c
+		$(srcdir)/config/nds32/nds32-utils.cc
diff --git a/gcc/config/nios2/nios2.cc b/gcc/config/nios2/nios2.cc
index 8c539fc..f193cde 100644
--- a/gcc/config/nios2/nios2.cc
+++ b/gcc/config/nios2/nios2.cc
@@ -4462,7 +4462,7 @@ nios2_pragma_target_parse (tree args, tree pop_target)
    We are just using this hook to add some additional error checking to
    the default behavior.  GCC does not provide a target hook for merging
    the target options, and only correctly handles merging empty vs non-empty
-   option data; see merge_decls() in c-decl.c.
+   option data; see merge_decls() in c-decl.cc.
    So here we require either that at least one of the decls has empty
    target options, or that the target options/data be identical.  */
 static tree
diff --git a/gcc/config/nvptx/nvptx-protos.h b/gcc/config/nvptx/nvptx-protos.h
index ef23615..3d6ad14 100644
--- a/gcc/config/nvptx/nvptx-protos.h
+++ b/gcc/config/nvptx/nvptx-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for exported functions defined in nvptx.c.
+/* Prototypes for exported functions defined in nvptx.cc.
    Copyright (C) 2014-2022 Free Software Foundation, Inc.
    Contributed by Bernd Schmidt <bernds@codesourcery.com>
 
diff --git a/gcc/config/nvptx/nvptx.cc b/gcc/config/nvptx/nvptx.cc
index 5cc5e01..20fd893 100644
--- a/gcc/config/nvptx/nvptx.cc
+++ b/gcc/config/nvptx/nvptx.cc
@@ -6793,7 +6793,7 @@ nvptx_goacc_expand_var_decl (tree var)
 		    var, "gang");
 	  if (dump_file && (dump_flags & TDF_DETAILS))
 	    {
-	      /* 'dumpfile.c:dump_loc' */
+	      /* 'dumpfile.cc:dump_loc' */
 	      fprintf (dump_file, "%s:%d:%d: ", LOCATION_FILE (loc),
 		       LOCATION_LINE (loc), LOCATION_COLUMN (loc));
 	      fprintf (dump_file, "%s: ", "note");
diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index d61bd70..9fda2f0 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -36,7 +36,7 @@
 
 #define TARGET_CPU_CPP_BUILTINS() nvptx_cpu_cpp_builtins ()
 
-/* Avoid the default in ../../gcc.c, which adds "-pthread", which is not
+/* Avoid the default in ../../gcc.cc, which adds "-pthread", which is not
    supported for nvptx.  */
 #define GOMP_SELF_SPECS ""
 
diff --git a/gcc/config/nvptx/t-nvptx b/gcc/config/nvptx/t-nvptx
index d33bacd..b170766 100644
--- a/gcc/config/nvptx/t-nvptx
+++ b/gcc/config/nvptx/t-nvptx
@@ -1,10 +1,10 @@
-nvptx-c.o: $(srcdir)/config/nvptx/nvptx-c.c
+nvptx-c.o: $(srcdir)/config/nvptx/nvptx-c.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
 CFLAGS-mkoffload.o += $(DRIVER_DEFINES) \
 	-DGCC_INSTALL_NAME=\"$(GCC_INSTALL_NAME)\"
-mkoffload.o: $(srcdir)/config/nvptx/mkoffload.c
+mkoffload.o: $(srcdir)/config/nvptx/mkoffload.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 ALL_HOST_OBJS += mkoffload.o
diff --git a/gcc/config/nvptx/t-omp-device b/gcc/config/nvptx/t-omp-device
index 6d03b43..8765d9f 100644
--- a/gcc/config/nvptx/t-omp-device
+++ b/gcc/config/nvptx/t-omp-device
@@ -1,4 +1,4 @@
-omp-device-properties-nvptx: $(srcdir)/config/nvptx/nvptx.c
+omp-device-properties-nvptx: $(srcdir)/config/nvptx/nvptx.cc
 	echo kind: gpu > $@
 	echo arch: nvptx >> $@
 	echo isa: sm_30 sm_35 >> $@
diff --git a/gcc/config/pa/elf.h b/gcc/config/pa/elf.h
index 2c2f249..b58659c 100644
--- a/gcc/config/pa/elf.h
+++ b/gcc/config/pa/elf.h
@@ -17,7 +17,7 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-/* So we can conditionalize small amounts of code in pa.c or pa.md.  */
+/* So we can conditionalize small amounts of code in pa.cc or pa.md.  */
 #define OBJ_ELF
 
 #define ENDFILE_SPEC "crtend.o%s"
diff --git a/gcc/config/pa/pa-linux.h b/gcc/config/pa/pa-linux.h
index ea7157d..5af11a1 100644
--- a/gcc/config/pa/pa-linux.h
+++ b/gcc/config/pa/pa-linux.h
@@ -100,7 +100,7 @@ along with GCC; see the file COPYING3.  If not see
 #define GLOBAL_ASM_OP ".globl "
 
 /* FIXME: Hacked from the <elfos.h> one so that we avoid multiple
-   labels in a function declaration (since pa.c seems determined to do
+   labels in a function declaration (since pa.cc seems determined to do
    it differently).  */
 
 #undef ASM_DECLARE_FUNCTION_NAME
diff --git a/gcc/config/pa/pa-netbsd.h b/gcc/config/pa/pa-netbsd.h
index d52c4d5..f5eaec6 100644
--- a/gcc/config/pa/pa-netbsd.h
+++ b/gcc/config/pa/pa-netbsd.h
@@ -95,7 +95,7 @@ along with GCC; see the file COPYING3.  If not see
 #define GLOBAL_ASM_OP ".globl "
 
 /* FIXME: Hacked from the <elfos.h> one so that we avoid multiple
-   labels in a function declaration (since pa.c seems determined to do
+   labels in a function declaration (since pa.cc seems determined to do
    it differently)  */
 
 #undef ASM_DECLARE_FUNCTION_NAME
diff --git a/gcc/config/pa/pa-openbsd.h b/gcc/config/pa/pa-openbsd.h
index 6145298..455294f 100644
--- a/gcc/config/pa/pa-openbsd.h
+++ b/gcc/config/pa/pa-openbsd.h
@@ -69,7 +69,7 @@ along with GCC; see the file COPYING3.  If not see
 #undef TARGET_ASM_GLOBALIZE_LABEL
 
 /* FIXME: Hacked from the <elfos.h> one so that we avoid multiple
-   labels in a function declaration (since pa.c seems determined to do
+   labels in a function declaration (since pa.cc seems determined to do
    it differently)  */
 
 #undef ASM_DECLARE_FUNCTION_NAME
diff --git a/gcc/config/pa/pa-protos.h b/gcc/config/pa/pa-protos.h
index fcbffa7..d474d9e 100644
--- a/gcc/config/pa/pa-protos.h
+++ b/gcc/config/pa/pa-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for pa.c functions used in the md file & elsewhere.
+/* Prototypes for pa.cc functions used in the md file & elsewhere.
    Copyright (C) 2000-2022 Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -21,7 +21,7 @@ along with GCC; see the file COPYING3.  If not see
 /* Prototype function used in various macros.  */
 extern rtx pa_eh_return_handler_rtx (void);
 
-/* Define functions in pa.c and used in insn-output.c.  */
+/* Define functions in pa.cc and used in insn-output.cc.  */
 
 extern const char *pa_output_and (rtx *);
 extern const char *pa_output_64bit_and (rtx *);
@@ -67,7 +67,7 @@ extern int pa_attr_length_indirect_call (rtx_insn *);
 extern rtx pa_legitimize_reload_address (rtx, machine_mode,
 					 int, int, int);
 
-/* Declare functions defined in pa.c and used in templates.  */
+/* Declare functions defined in pa.cc and used in templates.  */
 
 extern rtx pa_return_addr_rtx (int, rtx);
 
@@ -89,7 +89,7 @@ extern void pa_expand_prologue (void);
 extern void pa_expand_epilogue (void);
 extern bool pa_can_use_return_insn (void);
 
-/* Miscellaneous functions in pa.c.  */
+/* Miscellaneous functions in pa.cc.  */
 #ifdef TREE_CODE
 extern int pa_reloc_needed (tree);
 extern bool pa_return_in_memory (const_tree, const_tree);
@@ -112,6 +112,6 @@ extern void hppa_profile_hook (int);
 
 extern const int pa_magic_milli[];
 
-/* Routines implemented in pa-d.c  */
+/* Routines implemented in pa-d.cc  */
 extern void pa_d_target_versions (void);
 extern void pa_d_register_target_info (void);
diff --git a/gcc/config/pa/pa.cc b/gcc/config/pa/pa.cc
index b334518..54ab486 100644
--- a/gcc/config/pa/pa.cc
+++ b/gcc/config/pa/pa.cc
@@ -1,6 +1,6 @@
-/* Subroutines for insn-output.c for HPPA.
+/* Subroutines for insn-output.cc for HPPA.
    Copyright (C) 1992-2022 Free Software Foundation, Inc.
-   Contributed by Tim Moore (moore@cs.utah.edu), based on sparc.c
+   Contributed by Tim Moore (moore@cs.utah.edu), based on sparc.cc
 
 This file is part of GCC.
 
@@ -1026,7 +1026,7 @@ mem_shadd_or_shadd_rtx_p (rtx x)
 
 /* Try machine-dependent ways of modifying an illegitimate address
    to be legitimate.  If we find one, return the new, valid address.
-   This macro is used in only one place: `memory_address' in explow.c.
+   This macro is used in only one place: `memory_address' in explow.cc.
 
    OLDX is the address as it was before break_out_memory_refs was called.
    In some cases it is useful to look at this to decide what needs to be done.
@@ -10038,7 +10038,7 @@ som_output_text_section_asm_op (const char *data ATTRIBUTE_UNUSED)
 	     function has been completed.  So, we are changing to the
 	     text section to output debugging information.  Thus, we
 	     need to forget that we are in the text section so that
-	     varasm.c will call us when text_section is selected again.  */
+	     varasm.cc will call us when text_section is selected again.  */
 	  gcc_assert (!cfun || !cfun->machine
 		      || cfun->machine->in_nsubspa == 2);
 	  in_section = NULL;
diff --git a/gcc/config/pa/pa.h b/gcc/config/pa/pa.h
index 26a2d43..92d3d18 100644
--- a/gcc/config/pa/pa.h
+++ b/gcc/config/pa/pa.h
@@ -142,7 +142,7 @@ extern unsigned long total_code_bytes;
 /* This used to be zero (no max length), but big enums and such can
    cause huge strings which killed gas.
 
-   We also have to avoid lossage in dbxout.c -- it does not compute the
+   We also have to avoid lossage in dbxout.cc -- it does not compute the
    string size accurately, so we are real conservative here.  */
 #undef DBX_CONTIN_LENGTH
 #define DBX_CONTIN_LENGTH 3000
@@ -680,7 +680,7 @@ struct hppa_args {int words, nargs_prototype, incoming, indirect; };
 /* The profile counter if emitted must come before the prologue.  */
 #define PROFILE_BEFORE_PROLOGUE 1
 
-/* We never want final.c to emit profile counters.  When profile
+/* We never want final.cc to emit profile counters.  When profile
    counters are required, we have to defer emitting them to the end
    of the current file.  */
 #define NO_PROFILE_COUNTERS 1
@@ -730,7 +730,7 @@ extern int may_call_alloca;
    They give nonzero only if X is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 
 #define REGNO_OK_FOR_INDEX_P(X) \
@@ -919,7 +919,7 @@ extern int may_call_alloca;
 
 /* Try a machine-dependent way of reloading an illegitimate address
    operand.  If we find one, push the reload and jump to WIN.  This
-   macro is used in only one place: `find_reloads_address' in reload.c.  */
+   macro is used in only one place: `find_reloads_address' in reload.cc.  */
 
 #define LEGITIMIZE_RELOAD_ADDRESS(AD, MODE, OPNUM, TYPE, IND_L, WIN) 	     \
 do {									     \
diff --git a/gcc/config/pa/pa.md b/gcc/config/pa/pa.md
index aacb403..76ae35d 100644
--- a/gcc/config/pa/pa.md
+++ b/gcc/config/pa/pa.md
@@ -3261,7 +3261,7 @@
 ;; If the count is run-time determined, the register with the byte count
 ;; is clobbered by the copying code, and therefore it is forced to operand 2.
 ;;
-;; We used to clobber operands 0 and 1.  However, a change to regrename.c
+;; We used to clobber operands 0 and 1.  However, a change to regrename.cc
 ;; broke this semantic for pseudo registers.  We can't use match_scratch
 ;; as this requires two registers in the class R1_REGS when the MEMs for
 ;; operands 0 and 1 are both equivalent to symbolic MEMs.  Thus, we are
@@ -3449,7 +3449,7 @@
 ;; If the count is run-time determined, the register with the byte count
 ;; is clobbered by the copying code, and therefore it is forced to operand 2.
 ;;
-;; We used to clobber operands 0 and 1.  However, a change to regrename.c
+;; We used to clobber operands 0 and 1.  However, a change to regrename.cc
 ;; broke this semantic for pseudo registers.  We can't use match_scratch
 ;; as this requires two registers in the class R1_REGS when the MEMs for
 ;; operands 0 and 1 are both equivalent to symbolic MEMs.  Thus, we are
@@ -6663,7 +6663,7 @@
 	      DONE;
 	    }
 	}
-      /* Fallback to using optabs.c's expand_doubleword_shift.  */
+      /* Fallback to using optabs.cc's expand_doubleword_shift.  */
       FAIL;
     }
   if (GET_CODE (operands[2]) != CONST_INT)
@@ -6713,7 +6713,7 @@
 	  DONE;
 	}
     }
-  /* Fallback to using optabs.c's expand_doubleword_shift.  */
+  /* Fallback to using optabs.cc's expand_doubleword_shift.  */
   FAIL;
 })
 
diff --git a/gcc/config/pa/som.h b/gcc/config/pa/som.h
index 586326c..d2510e9 100644
--- a/gcc/config/pa/som.h
+++ b/gcc/config/pa/som.h
@@ -17,7 +17,7 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-/* So we can conditionalize small amounts of code in pa.c or pa.md.  */
+/* So we can conditionalize small amounts of code in pa.cc or pa.md.  */
 #undef TARGET_SOM
 #define TARGET_SOM 1
 
diff --git a/gcc/config/pa/t-pa b/gcc/config/pa/t-pa
index fbd05d2..2428280 100644
--- a/gcc/config/pa/t-pa
+++ b/gcc/config/pa/t-pa
@@ -1,4 +1,4 @@
-pa-d.o: $(srcdir)/config/pa/pa-d.c
+pa-d.o: $(srcdir)/config/pa/pa-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/pdp11/pdp11.cc b/gcc/config/pdp11/pdp11.cc
index 63f4642..f7482df 100644
--- a/gcc/config/pdp11/pdp11.cc
+++ b/gcc/config/pdp11/pdp11.cc
@@ -66,7 +66,7 @@ static void decode_pdp11_d (const struct real_format *,
 			    REAL_VALUE_TYPE *, const long *);
 
 /* These two are taken from the corresponding vax descriptors
-   in real.c, changing only the encode/decode routine pointers.  */
+   in real.cc, changing only the encode/decode routine pointers.  */
 const struct real_format pdp11_f_format =
   {
     encode_pdp11_f,
diff --git a/gcc/config/pdp11/pdp11.h b/gcc/config/pdp11/pdp11.h
index 22bede6..b7d66c3 100644
--- a/gcc/config/pdp11/pdp11.h
+++ b/gcc/config/pdp11/pdp11.h
@@ -416,7 +416,7 @@ extern int current_first_parm_offset;
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 
 #define REGNO_OK_FOR_BASE_P(REGNO)  \
diff --git a/gcc/config/pdp11/pdp11.md b/gcc/config/pdp11/pdp11.md
index d9c769f..a46efc1 100644
--- a/gcc/config/pdp11/pdp11.md
+++ b/gcc/config/pdp11/pdp11.md
@@ -2154,7 +2154,7 @@
 
 ;; Note that there is no corresponding CC setter pattern.
 ;; The reason is that it won't be generated, because
-;; compare-elim.c only does the transformation on input
+;; compare-elim.cc only does the transformation on input
 ;; insns that have a two-element PARALLEL, as opposed to
 ;; the three-element one we have here.     
 (define_insn "divmodhi4_nocc"
diff --git a/gcc/config/pdp11/t-pdp11 b/gcc/config/pdp11/t-pdp11
index 8e8e24d..25cfbb5 100644
--- a/gcc/config/pdp11/t-pdp11
+++ b/gcc/config/pdp11/t-pdp11
@@ -22,7 +22,7 @@ MULTILIB_OPTIONS = msoft-float
 LIBGCC2_CFLAGS = -Os
 CRTSTUFF_T_CFLAGS = -Os
 
-# Because the pdp11 POINTER_SIZE is only 16, in dwarf2out.c,
+# Because the pdp11 POINTER_SIZE is only 16, in dwarf2out.cc,
 # DWARF_ARANGES_PAD_SIZE is 0, thus a loop in output_aranges that checks
 # (i < (unsigned) DWARF_ARANGES_PAD_SIZE) elicits a warning that the
 # comparison is always false.
diff --git a/gcc/config/pru/pru.md b/gcc/config/pru/pru.md
index a61255b..68dcab2 100644
--- a/gcc/config/pru/pru.md
+++ b/gcc/config/pru/pru.md
@@ -432,7 +432,7 @@
 ;; We define it solely to allow combine to choose SImode
 ;; for word mode when trying to match our cbranch_qbbx_* insn.
 ;;
-;; Check how combine.c:make_extraction() uses
+;; Check how combine.cc:make_extraction() uses
 ;; get_best_reg_extraction_insn() to select the op size.
 (define_insn "extzv<mode>"
   [(set (match_operand:QISI 0 "register_operand"	"=r")
diff --git a/gcc/config/pru/t-pru b/gcc/config/pru/t-pru
index a635b91..86b1d7a 100644
--- a/gcc/config/pru/t-pru
+++ b/gcc/config/pru/t-pru
@@ -22,10 +22,10 @@
 # Unfortunately mabi=ti is not feature-complete enough to build newlib.
 # Hence we cannot present mabi=gnu/ti as a multilib option.
 
-pru-pragma.o: $(srcdir)/config/pru/pru-pragma.c $(RTL_H) $(TREE_H) \
+pru-pragma.o: $(srcdir)/config/pru/pru-pragma.cc $(RTL_H) $(TREE_H) \
 		$(CONFIG_H) $(TM_H) $(srcdir)/config/pru/pru-protos.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
-pru-passes.o: $(srcdir)/config/pru/pru-passes.c $(RTL_H) $(TREE_H) \
+pru-passes.o: $(srcdir)/config/pru/pru-passes.cc $(RTL_H) $(TREE_H) \
 		$(CONFIG_H) $(TM_H) $(srcdir)/config/pru/pru-protos.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/riscv/riscv-protos.h b/gcc/config/riscv/riscv-protos.h
index 6bca84c..20c2381 100644
--- a/gcc/config/riscv/riscv-protos.h
+++ b/gcc/config/riscv/riscv-protos.h
@@ -35,7 +35,7 @@ enum riscv_symbol_type {
 };
 #define NUM_SYMBOL_TYPES (SYMBOL_TLS_GD + 1)
 
-/* Routines implemented in riscv.c.  */
+/* Routines implemented in riscv.cc.  */
 extern enum riscv_symbol_type riscv_classify_symbolic_expression (rtx);
 extern bool riscv_symbolic_constant_p (rtx, enum riscv_symbol_type *);
 extern int riscv_regno_mode_ok_for_base_p (int, machine_mode, bool);
@@ -75,20 +75,20 @@ extern bool riscv_store_data_bypass_p (rtx_insn *, rtx_insn *);
 extern rtx riscv_gen_gpr_save_insn (struct riscv_frame_info *);
 extern bool riscv_gpr_save_operation_p (rtx);
 
-/* Routines implemented in riscv-c.c.  */
+/* Routines implemented in riscv-c.cc.  */
 void riscv_cpu_cpp_builtins (cpp_reader *);
 
-/* Routines implemented in riscv-d.c  */
+/* Routines implemented in riscv-d.cc  */
 extern void riscv_d_target_versions (void);
 extern void riscv_d_register_target_info (void);
 
-/* Routines implemented in riscv-builtins.c.  */
+/* Routines implemented in riscv-builtins.cc.  */
 extern void riscv_atomic_assign_expand_fenv (tree *, tree *, tree *);
 extern rtx riscv_expand_builtin (tree, rtx, rtx, machine_mode, int);
 extern tree riscv_builtin_decl (unsigned int, bool);
 extern void riscv_init_builtins (void);
 
-/* Routines implemented in riscv-common.c.  */
+/* Routines implemented in riscv-common.cc.  */
 extern std::string riscv_arch_str (bool version_p = true);
 
 extern bool riscv_hard_regno_rename_ok (unsigned, unsigned);
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index d9dadaa..7c80678 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -4933,7 +4933,7 @@ riscv_output_mi_thunk (FILE *file, tree thunk_fndecl ATTRIBUTE_UNUSED,
   SIBLING_CALL_P (insn) = 1;
 
   /* Run just enough of rest_of_compilation.  This sequence was
-     "borrowed" from alpha.c.  */
+     "borrowed" from alpha.cc.  */
   insn = get_insns ();
   split_all_insns_noflow ();
   shorten_branches (insn);
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 7c0473c..6956684 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -147,7 +147,7 @@ ASM_MISA_SPEC
 #define MIN_UNITS_PER_WORD 4
 #endif
 
-/* Allows SImode op in builtin overflow pattern, see internal-fn.c.  */
+/* Allows SImode op in builtin overflow pattern, see internal-fn.cc.  */
 #undef TARGET_MIN_ARITHMETIC_PRECISION
 #define TARGET_MIN_ARITHMETIC_PRECISION riscv_min_arithmetic_precision
 
@@ -996,7 +996,7 @@ extern unsigned riscv_stack_boundary;
    offset (an unsigned 5-bit value scaled by 4).  */
 #define CSW_MAX_OFFSET (((4LL << C_S_BITS) - 1) & ~3)
 
-/* Called from RISCV_REORG, this is defined in riscv-sr.c.  */
+/* Called from RISCV_REORG, this is defined in riscv-sr.cc.  */
 
 extern void riscv_remove_unneeded_save_restore_calls (void);
 
diff --git a/gcc/config/riscv/t-riscv b/gcc/config/riscv/t-riscv
index 1215ea8..096d70e 100644
--- a/gcc/config/riscv/t-riscv
+++ b/gcc/config/riscv/t-riscv
@@ -1,25 +1,25 @@
-riscv-builtins.o: $(srcdir)/config/riscv/riscv-builtins.c $(CONFIG_H) \
+riscv-builtins.o: $(srcdir)/config/riscv/riscv-builtins.cc $(CONFIG_H) \
   $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(TREE_H) $(RECOG_H) langhooks.h \
   $(DIAGNOSTIC_CORE_H) $(OPTABS_H) $(srcdir)/config/riscv/riscv-ftypes.def \
   $(srcdir)/config/riscv/riscv-modes.def
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/riscv/riscv-builtins.c
+		$(srcdir)/config/riscv/riscv-builtins.cc
 
-riscv-sr.o: $(srcdir)/config/riscv/riscv-sr.c $(CONFIG_H) \
+riscv-sr.o: $(srcdir)/config/riscv/riscv-sr.cc $(CONFIG_H) \
   $(SYSTEM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/riscv/riscv-sr.c
+		$(srcdir)/config/riscv/riscv-sr.cc
 
-riscv-c.o: $(srcdir)/config/riscv/riscv-c.c $(CONFIG_H) $(SYSTEM_H) \
+riscv-c.o: $(srcdir)/config/riscv/riscv-c.cc $(CONFIG_H) $(SYSTEM_H) \
     coretypes.h $(TM_H) $(TREE_H) output.h $(C_COMMON_H) $(TARGET_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/riscv/riscv-c.c
+		$(srcdir)/config/riscv/riscv-c.cc
 
-riscv-d.o: $(srcdir)/config/riscv/riscv-d.c
+riscv-d.o: $(srcdir)/config/riscv/riscv-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-riscv-shorten-memrefs.o: $(srcdir)/config/riscv/riscv-shorten-memrefs.c
+riscv-shorten-memrefs.o: $(srcdir)/config/riscv/riscv-shorten-memrefs.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/rl78/rl78.cc b/gcc/config/rl78/rl78.cc
index a2bd788..b3727c0 100644
--- a/gcc/config/rl78/rl78.cc
+++ b/gcc/config/rl78/rl78.cc
@@ -4778,7 +4778,7 @@ rl78_asm_ctor_dtor (rtx symbol, int priority, bool is_ctor)
   if (priority != DEFAULT_INIT_PRIORITY)
     {
       /* This section of the function is based upon code copied
-	 from: gcc/varasm.c:get_cdtor_priority_section().  */
+	 from: gcc/varasm.cc:get_cdtor_priority_section().  */
       char buf[18];
 
       sprintf (buf, "%s.%.5u", is_ctor ? ".ctors" : ".dtors",
diff --git a/gcc/config/rl78/t-rl78 b/gcc/config/rl78/t-rl78
index cadd632..cd2a5084 100644
--- a/gcc/config/rl78/t-rl78
+++ b/gcc/config/rl78/t-rl78
@@ -18,7 +18,7 @@
 # License along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-rl78-c.o: $(srcdir)/config/rl78/rl78-c.c $(RTL_H) $(TREE_H) $(CONFIG_H) $(TM_H)
+rl78-c.o: $(srcdir)/config/rl78/rl78-c.cc $(RTL_H) $(TREE_H) $(CONFIG_H) $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
 # Enable multilibs:
diff --git a/gcc/config/rs6000/aix.h b/gcc/config/rs6000/aix.h
index 954c98e..ad3238b 100644
--- a/gcc/config/rs6000/aix.h
+++ b/gcc/config/rs6000/aix.h
@@ -65,10 +65,10 @@
 
    The default value for this macro is `STACK_POINTER_OFFSET' plus the
    length of the outgoing arguments.  The default is correct for most
-   machines.  See `function.c' for details.
+   machines.  See `function.cc' for details.
 
    This value must be a multiple of STACK_BOUNDARY (hard coded in
-   `emit-rtl.c').  */
+   `emit-rtl.cc').  */
 #undef STACK_DYNAMIC_OFFSET
 #define STACK_DYNAMIC_OFFSET(FUNDECL)					\
    RS6000_ALIGN (crtl->outgoing_args_size.to_constant ()		\
diff --git a/gcc/config/rs6000/aix71.h b/gcc/config/rs6000/aix71.h
index afc506c..57e07bc 100644
--- a/gcc/config/rs6000/aix71.h
+++ b/gcc/config/rs6000/aix71.h
@@ -73,7 +73,7 @@ do {									\
 #define ASM_SPEC_COMMON "-u %(asm_cpu)"
 
 /* Common ASM definitions used by ASM_SPEC amongst the various targets for
-   handling -mcpu=xxx switches.  There is a parallel list in driver-rs6000.c to
+   handling -mcpu=xxx switches.  There is a parallel list in driver-rs6000.cc to
    provide the default assembler options if the user uses -mcpu=native, so if
    you make changes here, make them there also.  */
 #undef ASM_CPU_SPEC
diff --git a/gcc/config/rs6000/aix72.h b/gcc/config/rs6000/aix72.h
index 2a92048..ca73acb 100644
--- a/gcc/config/rs6000/aix72.h
+++ b/gcc/config/rs6000/aix72.h
@@ -73,7 +73,7 @@ do {									\
 #define ASM_SPEC_COMMON "-u %(asm_cpu)"
 
 /* Common ASM definitions used by ASM_SPEC amongst the various targets for
-   handling -mcpu=xxx switches.  There is a parallel list in driver-rs6000.c to
+   handling -mcpu=xxx switches.  There is a parallel list in driver-rs6000.cc to
    provide the default assembler options if the user uses -mcpu=native, so if
    you make changes here, make them there also.  */
 #undef ASM_CPU_SPEC
diff --git a/gcc/config/rs6000/aix73.h b/gcc/config/rs6000/aix73.h
index 2bc42ec..8baa27e 100644
--- a/gcc/config/rs6000/aix73.h
+++ b/gcc/config/rs6000/aix73.h
@@ -73,7 +73,7 @@ do {									\
 #define ASM_SPEC_COMMON "-u %(asm_cpu)"
 
 /* Common ASM definitions used by ASM_SPEC amongst the various targets for
-   handling -mcpu=xxx switches.  There is a parallel list in driver-rs6000.c to
+   handling -mcpu=xxx switches.  There is a parallel list in driver-rs6000.cc to
    provide the default assembler options if the user uses -mcpu=native, so if
    you make changes here, make them there also.  */
 #undef ASM_CPU_SPEC
diff --git a/gcc/config/rs6000/darwin.h b/gcc/config/rs6000/darwin.h
index 1ec9c20..b5cef42 100644
--- a/gcc/config/rs6000/darwin.h
+++ b/gcc/config/rs6000/darwin.h
@@ -246,10 +246,10 @@
 
    The default value for this macro is `STACK_POINTER_OFFSET' plus the
    length of the outgoing arguments.  The default is correct for most
-   machines.  See `function.c' for details.
+   machines.  See `function.cc' for details.
 
    This value must be a multiple of STACK_BOUNDARY (hard coded in
-   `emit-rtl.c').  */
+   `emit-rtl.cc').  */
 
 #undef STACK_DYNAMIC_OFFSET
 #define STACK_DYNAMIC_OFFSET(FUNDECL)					\
@@ -306,7 +306,7 @@
 #define GLOBAL_ASM_OP "\t.globl "
 #undef TARGET_ASM_GLOBALIZE_LABEL
 
-/* This is how to output an internal label prefix.  rs6000.c uses this
+/* This is how to output an internal label prefix.  rs6000.cc uses this
    when generating traceback tables.  */
 /* Not really used for Darwin?  */
 
diff --git a/gcc/config/rs6000/driver-rs6000.cc b/gcc/config/rs6000/driver-rs6000.cc
index 631054d..ec890e0 100644
--- a/gcc/config/rs6000/driver-rs6000.cc
+++ b/gcc/config/rs6000/driver-rs6000.cc
@@ -534,7 +534,7 @@ static const struct asm_name asm_names[] = {
 #endif
 };
 
-/* This will be called by the spec parser in gcc.c when it sees
+/* This will be called by the spec parser in gcc.cc when it sees
    a %:local_cpu_detect(args) construct.  Currently it will be called
    with either "arch" or "tune" as argument depending on if -march=native
    or -mtune=native is to be substituted.
diff --git a/gcc/config/rs6000/freebsd.h b/gcc/config/rs6000/freebsd.h
index c248aee..29ada25 100644
--- a/gcc/config/rs6000/freebsd.h
+++ b/gcc/config/rs6000/freebsd.h
@@ -51,8 +51,8 @@
 /************************[  Target stuff  ]***********************************/
 
 /* Define the actual types of some ANSI-mandated types.  
-   Needs to agree with <machine/ansi.h>.  GCC defaults come from c-decl.c,
-   c-common.c, and config/<arch>/<arch>.h.  */
+   Needs to agree with <machine/ansi.h>.  GCC defaults come from c-decl.cc,
+   c-common.cc, and config/<arch>/<arch>.h.  */
 
 #undef  SIZE_TYPE
 #define SIZE_TYPE "unsigned int"
diff --git a/gcc/config/rs6000/freebsd64.h b/gcc/config/rs6000/freebsd64.h
index 5de20f1..a73752a 100644
--- a/gcc/config/rs6000/freebsd64.h
+++ b/gcc/config/rs6000/freebsd64.h
@@ -239,8 +239,8 @@ extern int dot_symbols;
 /************************[  Target stuff  ]***********************************/
 
 /* Define the actual types of some ANSI-mandated types.  
-   Needs to agree with <machine/ansi.h>.  GCC defaults come from c-decl.c,
-   c-common.c, and config/<arch>/<arch>.h.  */
+   Needs to agree with <machine/ansi.h>.  GCC defaults come from c-decl.cc,
+   c-common.cc, and config/<arch>/<arch>.h.  */
 
 
 #undef  SIZE_TYPE
diff --git a/gcc/config/rs6000/lynx.h b/gcc/config/rs6000/lynx.h
index f6e7d23..dcf5fc4 100644
--- a/gcc/config/rs6000/lynx.h
+++ b/gcc/config/rs6000/lynx.h
@@ -81,7 +81,7 @@
 #undef SIZE_TYPE
 #undef ASM_OUTPUT_ALIGN
 
-/* The file rs6000.c defines TARGET_HAVE_TLS unconditionally to the
+/* The file rs6000.cc defines TARGET_HAVE_TLS unconditionally to the
    value of HAVE_AS_TLS.  HAVE_AS_TLS is true as gas support for TLS
    is detected by configure.  Override the definition to false.  */
 
diff --git a/gcc/config/rs6000/rbtree.cc b/gcc/config/rs6000/rbtree.cc
index 00ab9e9..065e8fc 100644
--- a/gcc/config/rs6000/rbtree.cc
+++ b/gcc/config/rs6000/rbtree.cc
@@ -1,4 +1,4 @@
-/* Partial red-black tree implementation for rs6000-gen-builtins.c.
+/* Partial red-black tree implementation for rs6000-gen-builtins.cc.
    Copyright (C) 2020-2022 Free Software Foundation, Inc.
    Contributed by Bill Schmidt, IBM <wschmidt@linux.ibm.com>
 
diff --git a/gcc/config/rs6000/rbtree.h b/gcc/config/rs6000/rbtree.h
index 4ba88a0..9ee0f91 100644
--- a/gcc/config/rs6000/rbtree.h
+++ b/gcc/config/rs6000/rbtree.h
@@ -1,4 +1,4 @@
-/* Partial red-black tree implementation for rs6000-gen-builtins.c.
+/* Partial red-black tree implementation for rs6000-gen-builtins.cc.
    Copyright (C) 2020-2022 Free Software Foundation, Inc.
    Contributed by Bill Schmidt, IBM <wschmidt@linux.ibm.com>
 
diff --git a/gcc/config/rs6000/rs6000-c.cc b/gcc/config/rs6000/rs6000-c.cc
index 24a081c..145421a 100644
--- a/gcc/config/rs6000/rs6000-c.cc
+++ b/gcc/config/rs6000/rs6000-c.cc
@@ -358,7 +358,7 @@ rs6000_target_modify_macros (bool define_p, HOST_WIDE_INT flags,
      flags are enabled or disabled implicitly, based on compiler
      defaults, configuration choices, and on the presence of certain
      related command-line options.  Many, but not all, of these
-     implicit behaviors can be found in file "rs6000.c", the
+     implicit behaviors can be found in file "rs6000.cc", the
      rs6000_option_override_internal() function.
 
      In general, each of the flags may be automatically enabled in
diff --git a/gcc/config/rs6000/rs6000-call.cc b/gcc/config/rs6000/rs6000-call.cc
index c78b8b0..8968929 100644
--- a/gcc/config/rs6000/rs6000-call.cc
+++ b/gcc/config/rs6000/rs6000-call.cc
@@ -3335,7 +3335,7 @@ rs6000_invalid_builtin (enum rs6000_gen_builtins fncode)
 }
 
 /* Target hook for early folding of built-ins, shamelessly stolen
-   from ia64.c.  */
+   from ia64.cc.  */
 
 tree
 rs6000_fold_builtin (tree fndecl ATTRIBUTE_UNUSED,
@@ -5493,7 +5493,7 @@ rs6000_expand_builtin (tree exp, rtx target, rtx /* subtarget */,
      IBM extended double (KFmode) or long double is IEEE 128-bit (TFmode).
      It is simpler if we only define one variant of the built-in function,
      and switch the code when defining it, rather than defining two built-
-     ins and using the overload table in rs6000-c.c to switch between the
+     ins and using the overload table in rs6000-c.cc to switch between the
      two.  If we don't have the proper assembler, don't do this switch
      because CODE_FOR_*kf* and CODE_FOR_*tf* will be CODE_FOR_nothing.  */
   if (FLOAT128_IEEE_P (TFmode))
@@ -6122,7 +6122,7 @@ rs6000_init_builtins (void)
      format is IBM extended double.
 
      For IEEE 128-bit floating point, always create the type __ieee128.  If the
-     user used -mfloat128, rs6000-c.c will create a define from __float128 to
+     user used -mfloat128, rs6000-c.cc will create a define from __float128 to
      __ieee128.  */
   if (TARGET_FLOAT128_TYPE)
     {
diff --git a/gcc/config/rs6000/rs6000-cpus.def b/gcc/config/rs6000/rs6000-cpus.def
index 50719f4..325b219 100644
--- a/gcc/config/rs6000/rs6000-cpus.def
+++ b/gcc/config/rs6000/rs6000-cpus.def
@@ -44,7 +44,7 @@
 				 | OPTION_MASK_VSX)
 
 /* For now, don't provide an embedded version of ISA 2.07.  Do not set power8
-   fusion here, instead set it in rs6000.c if we are tuning for a power8
+   fusion here, instead set it in rs6000.cc if we are tuning for a power8
    system.  */
 #define ISA_2_7_MASKS_SERVER	(ISA_2_6_MASKS_SERVER			\
 				 | OPTION_MASK_P8_VECTOR		\
diff --git a/gcc/config/rs6000/rs6000-gen-builtins.cc b/gcc/config/rs6000/rs6000-gen-builtins.cc
index 7dd7ab3..6a0858a 100644
--- a/gcc/config/rs6000/rs6000-gen-builtins.cc
+++ b/gcc/config/rs6000/rs6000-gen-builtins.cc
@@ -2823,7 +2823,7 @@ write_init_ovld_table (void)
     }
 }
 
-/* Write everything to the initialization file (rs6000-builtins.c).
+/* Write everything to the initialization file (rs6000-builtins.cc).
    Return 1 if successful, 0 otherwise.  */
 static int
 write_init_file (void)
diff --git a/gcc/config/rs6000/rs6000-internal.h b/gcc/config/rs6000/rs6000-internal.h
index fa06fa7..2d1090e 100644
--- a/gcc/config/rs6000/rs6000-internal.h
+++ b/gcc/config/rs6000/rs6000-internal.h
@@ -78,8 +78,8 @@ extern const char *rs6000_machine;
 #define ALTIVEC_REG_BIT(REGNO) (0x80000000 >> ((REGNO) - FIRST_ALTIVEC_REGNO))
 
 
-/* Declare functions in rs6000-logue.c or called in rs6000.c
-   from rs6000-logue.c  */
+/* Declare functions in rs6000-logue.cc or called in rs6000.cc
+   from rs6000-logue.cc  */
 
 extern int uses_TOC (void);
 extern bool rs6000_global_entry_point_needed_p (void);
@@ -113,7 +113,7 @@ quad_address_offset_p (HOST_WIDE_INT offset)
   return (IN_RANGE (offset, -32768, 32767) && ((offset) & 0xf) == 0);
 }
 
-/* Mach-O (Darwin) support for longcalls, emitted from  rs6000-logue.c.  */
+/* Mach-O (Darwin) support for longcalls, emitted from  rs6000-logue.cc.  */
 
 #if TARGET_MACHO
 
@@ -127,8 +127,8 @@ extern vec<branch_island, va_gc> *branch_islands;
 
 #endif
 
-/* Declare functions in rs6000-call.c or called in rs6000.c
-   from rs6000-call.c  */
+/* Declare functions in rs6000-call.cc or called in rs6000.cc
+   from rs6000-call.cc  */
 extern int rs6000_darwin64_struct_check_p (machine_mode mode, const_tree type);
 extern bool rs6000_discover_homogeneous_aggregate (machine_mode mode,
 						   const_tree type,
diff --git a/gcc/config/rs6000/rs6000-logue.cc b/gcc/config/rs6000/rs6000-logue.cc
index 2727afb2..59fe1c8 100644
--- a/gcc/config/rs6000/rs6000-logue.cc
+++ b/gcc/config/rs6000/rs6000-logue.cc
@@ -1931,7 +1931,7 @@ interesting_frame_related_regno (unsigned int regno)
 {
   /* Saves apparently of r0 are actually saving LR.  It doesn't make
      sense to substitute the regno here to test save_reg_p (LR_REGNO).
-     We *know* LR needs saving, and dwarf2cfi.c is able to deduce that
+     We *know* LR needs saving, and dwarf2cfi.cc is able to deduce that
      (set (mem) (r0)) is saving LR from a prior (set (r0) (lr)) marked
      as frame related.  */
   if (regno == 0)
@@ -4922,7 +4922,7 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
 	 a REG_CFA_DEF_CFA note.  This must happen on the insn that
 	 restores the frame pointer, r31.  We may have already emitted
 	 a REG_CFA_DEF_CFA note, but that's OK;  A duplicate is
-	 discarded by dwarf2cfi.c/dwarf2out.c, and in any case would
+	 discarded by dwarf2cfi.cc/dwarf2out.cc, and in any case would
 	 be harmless if emitted.  */
       if (frame_pointer_needed)
 	{
diff --git a/gcc/config/rs6000/rs6000-overload.def b/gcc/config/rs6000/rs6000-overload.def
index 93ce650..e279153 100644
--- a/gcc/config/rs6000/rs6000-overload.def
+++ b/gcc/config/rs6000/rs6000-overload.def
@@ -1516,7 +1516,7 @@
     VEXPTEFP
 
 ; There are no actual builtins for vec_extract.  There is special handling for
-; this in altivec_resolve_overloaded_builtin in rs6000-c.c, where the call
+; this in altivec_resolve_overloaded_builtin in rs6000-c.cc, where the call
 ; is replaced by "pointer tricks."  The single overload here causes
 ; __builtin_vec_extract to be registered with the front end so this can
 ; happen.
@@ -1733,7 +1733,7 @@
     VGNB
 
 ; There are no actual builtins for vec_insert.  There is special handling for
-; this in altivec_resolve_overloaded_builtin in rs6000-c.c, where the call
+; this in altivec_resolve_overloaded_builtin in rs6000-c.cc, where the call
 ; is replaced by "pointer tricks."  The single overload here causes
 ; __builtin_vec_insert to be registered with the front end so this can happen.
 [VEC_INSERT, vec_insert, __builtin_vec_insert]
@@ -2480,7 +2480,7 @@
   void __builtin_vec_mtvscr (vui);
     MTVSCR  MTVSCR_VUI
 
-; Note that the entries for VEC_MUL are currently ignored.  See rs6000-c.c:
+; Note that the entries for VEC_MUL are currently ignored.  See rs6000-c.cc:
 ; altivec_resolve_overloaded_builtin, where there is special-case code for
 ; VEC_MUL.  TODO: Is this really necessary?  Investigate.  Seven missing
 ; prototypes here...no corresponding builtins.  Also added "vmulld" in P10
@@ -3017,7 +3017,7 @@
     VPRTYBQ  VPRTYBQ_U
 
 ; There are no actual builtins for vec_promote.  There is special handling for
-; this in altivec_resolve_overloaded_builtin in rs6000-c.c, where the call
+; this in altivec_resolve_overloaded_builtin in rs6000-c.cc, where the call
 ; is replaced by a constructor.  The single overload here causes
 ; __builtin_vec_promote to be registered with the front end so that can happen.
 [VEC_PROMOTE, vec_promote, __builtin_vec_promote]
@@ -3587,7 +3587,7 @@
     VXXSPLTI32DX_V4SF
 
 ; There are no actual builtins for vec_splats.  There is special handling for
-; this in altivec_resolve_overloaded_builtin in rs6000-c.c, where the call
+; this in altivec_resolve_overloaded_builtin in rs6000-c.cc, where the call
 ; is replaced by a constructor.  The single overload here causes
 ; __builtin_vec_splats to be registered with the front end so that can happen.
 [VEC_SPLATS, vec_splats, __builtin_vec_splats]
diff --git a/gcc/config/rs6000/rs6000-p8swap.cc b/gcc/config/rs6000/rs6000-p8swap.cc
index 0517ee4..d301bc3 100644
--- a/gcc/config/rs6000/rs6000-p8swap.cc
+++ b/gcc/config/rs6000/rs6000-p8swap.cc
@@ -66,7 +66,7 @@
    and stores may be removed.
 
    This pass uses some of the infrastructure and logical ideas from
-   the "web" pass in web.c.  We create maximal webs of computations
+   the "web" pass in web.cc.  We create maximal webs of computations
    fitting the description above using union-find.  Each such web is
    then optimized by removing its unnecessary xxswapdi instructions.
 
@@ -142,7 +142,7 @@
    constant pool, we can replace M with M' as above at no cost
    beyond adding a constant pool entry.  */
 
-/* This is based on the union-find logic in web.c.  web_entry_base is
+/* This is based on the union-find logic in web.cc.  web_entry_base is
    defined in df.h.  */
 class swap_web_entry : public web_entry_base
 {
diff --git a/gcc/config/rs6000/rs6000-protos.h b/gcc/config/rs6000/rs6000-protos.h
index 1d1c89c..e322ac0 100644
--- a/gcc/config/rs6000/rs6000-protos.h
+++ b/gcc/config/rs6000/rs6000-protos.h
@@ -21,7 +21,7 @@
 #ifndef GCC_RS6000_PROTOS_H
 #define GCC_RS6000_PROTOS_H
 
-/* Declare functions in rs6000.c */
+/* Declare functions in rs6000.cc */
 
 #ifdef RTX_CODE
 
@@ -313,7 +313,7 @@ extern void rs6000_asm_output_dwarf_datarel (FILE *file, int size,
 					     const char *label);
 extern long rs6000_const_f32_to_i32 (rtx operand);
 
-/* Declare functions in rs6000-c.c */
+/* Declare functions in rs6000-c.cc */
 
 extern void rs6000_pragma_longcall (struct cpp_reader *);
 extern void rs6000_cpu_cpp_builtins (struct cpp_reader *);
@@ -325,7 +325,7 @@ extern void rs6000_target_modify_macros (bool, HOST_WIDE_INT, HOST_WIDE_INT);
 extern void (*rs6000_target_modify_macros_ptr) (bool, HOST_WIDE_INT,
 						HOST_WIDE_INT);
 
-/* Declare functions in rs6000-d.c  */
+/* Declare functions in rs6000-d.cc  */
 extern void rs6000_d_target_versions (void);
 extern void rs6000_d_register_target_info (void);
 
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 7759f75..7a4ef5e 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -293,9 +293,9 @@ const char *tcb_verification_symbol = "__parse_hwcap_and_convert_at_platform";
 /* True if we have expanded a CPU builtin.  */
 bool cpu_builtin_p = false;
 
-/* Pointer to function (in rs6000-c.c) that can define or undefine target
+/* Pointer to function (in rs6000-c.cc) that can define or undefine target
    macros that have changed.  Languages that don't support the preprocessor
-   don't link in rs6000-c.c, so we can't call it directly.  */
+   don't link in rs6000-c.cc, so we can't call it directly.  */
 void (*rs6000_target_modify_macros_ptr) (bool, HOST_WIDE_INT, HOST_WIDE_INT);
 
 /* Simplfy register classes into simpler classifications.  We assume
@@ -9080,7 +9080,7 @@ legitimate_lo_sum_address_p (machine_mode mode, rtx x, int strict)
 
 /* Try machine-dependent ways of modifying an illegitimate address
    to be legitimate.  If we find one, return the new, valid address.
-   This is used from only one place: `memory_address' in explow.c.
+   This is used from only one place: `memory_address' in explow.cc.
 
    OLDX is the address as it was before break_out_memory_refs was
    called.  In some cases it is useful to look at this to decide what
@@ -9265,7 +9265,7 @@ rs6000_debug_legitimize_address (rtx x, rtx oldx, machine_mode mode)
   return ret;
 }
 
-/* This is called from dwarf2out.c via TARGET_ASM_OUTPUT_DWARF_DTPREL.
+/* This is called from dwarf2out.cc via TARGET_ASM_OUTPUT_DWARF_DTPREL.
    We need to emit DTP-relative relocations.  */
 
 static void rs6000_output_dwarf_dtprel (FILE *, int, rtx) ATTRIBUTE_UNUSED;
@@ -10004,7 +10004,7 @@ rs6000_mode_dependent_address (const_rtx addr)
 	 all bytes have the same high part address.  */
       return !legitimate_constant_pool_address_p (addr, QImode, false);
 
-    /* Auto-increment cases are now treated generically in recog.c.  */
+    /* Auto-increment cases are now treated generically in recog.cc.  */
     case PRE_MODIFY:
       return TARGET_UPDATE;
 
@@ -18344,12 +18344,12 @@ rs6000_adjust_priority (rtx_insn *insn ATTRIBUTE_UNUSED, int priority)
 	 dispatch slot.  */
       if (rs6000_sched_restricted_insns_priority == 1)
 	/* Attach highest priority to insn. This means that in
-	   haifa-sched.c:ready_sort(), dispatch-slot restriction considerations
+	   haifa-sched.cc:ready_sort(), dispatch-slot restriction considerations
 	   precede 'priority' (critical path) considerations.  */
 	return current_sched_info->sched_max_insns_priority;
       else if (rs6000_sched_restricted_insns_priority == 2)
 	/* Increase priority of insn by a minimal amount. This means that in
-	   haifa-sched.c:ready_sort(), only 'priority' (critical path)
+	   haifa-sched.cc:ready_sort(), only 'priority' (critical path)
 	   considerations precede dispatch-slot restriction considerations.  */
 	return (priority + 1);
     }
@@ -23989,7 +23989,7 @@ rs6000_c_mode_for_suffix (char suffix)
       /* At the moment, we are not defining a suffix for IBM extended double.
 	 If/when the default for -mabi=ieeelongdouble is changed, and we want
 	 to support __ibm128 constants in legacy library code, we may need to
-	 re-evalaute this decision.  Currently, c-lex.c only supports 'w' and
+	 re-evalaute this decision.  Currently, c-lex.cc only supports 'w' and
 	 'q' as machine dependent suffixes.  The x86_64 port uses 'w' for
 	 __float80 constants.  */
     }
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index a02dbbd..5fdb8f2 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -98,7 +98,7 @@
 #endif
 
 /* Common ASM definitions used by ASM_SPEC among the various targets for
-   handling -mcpu=xxx switches.  There is a parallel list in driver-rs6000.c to
+   handling -mcpu=xxx switches.  There is a parallel list in driver-rs6000.cc to
    provide the default assembler options if the user uses -mcpu=native, so if
    you make changes here, make them also there.  PR63177: Do not pass -mpower8
    to the assembler if -mpower9-vector was also used.  */
@@ -195,9 +195,9 @@ ASM_OPT_ANY
 
 /* -mcpu=native handling only makes sense with compiler running on
    an PowerPC chip.  If changing this condition, also change
-   the condition in driver-rs6000.c.  */
+   the condition in driver-rs6000.cc.  */
 #if defined(__powerpc__) || defined(__POWERPC__) || defined(_AIX)
-/* In driver-rs6000.c.  */
+/* In driver-rs6000.cc.  */
 extern const char *host_detect_local_cpu (int argc, const char **argv);
 #define EXTRA_SPEC_FUNCTIONS \
   { "local_cpu_detect", host_detect_local_cpu },
@@ -753,7 +753,7 @@ extern unsigned char rs6000_recip_bits[];
    machine.  If you don't define this, the default is two words.  */
 #define LONG_DOUBLE_TYPE_SIZE rs6000_long_double_type_size
 
-/* Work around rs6000_long_double_type_size dependency in ada/targtyps.c.  */
+/* Work around rs6000_long_double_type_size dependency in ada/targtyps.cc.  */
 #define WIDEST_HARDWARE_FP_SIZE 64
 
 /* Width in bits of a pointer.
@@ -1358,10 +1358,10 @@ extern enum reg_class rs6000_constraints[RS6000_CONSTRAINT_MAX];
 
    The default value for this macro is `STACK_POINTER_OFFSET' plus the
    length of the outgoing arguments.  The default is correct for most
-   machines.  See `function.c' for details.
+   machines.  See `function.cc' for details.
 
    This value must be a multiple of STACK_BOUNDARY (hard coded in
-   `emit-rtl.c').  */
+   `emit-rtl.cc').  */
 #define STACK_DYNAMIC_OFFSET(FUNDECL)					\
   RS6000_ALIGN (crtl->outgoing_args_size.to_constant ()			\
 		+ STACK_POINTER_OFFSET,					\
@@ -1607,7 +1607,7 @@ typedef struct rs6000_args
 /* #define RETURN_ADDR_IN_PREVIOUS_FRAME */
 
 /* Number of bytes into the frame return addresses can be found.  See
-   rs6000_stack_info in rs6000.c for more information on how the different
+   rs6000_stack_info in rs6000.cc for more information on how the different
    abi's store the return address.  */
 #define RETURN_ADDRESS_OFFSET \
   ((DEFAULT_ABI == ABI_V4 ? 4 : 8) << (TARGET_64BIT ? 1 : 0))
@@ -1661,7 +1661,7 @@ typedef struct rs6000_args
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 
 #define REGNO_OK_FOR_INDEX_P(REGNO)				\
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 6f74075..59531b6 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -5146,7 +5146,7 @@
    (set_attr "isa" "*,p8v")])
 
 ;; This expander is here to avoid FLOAT_WORDS_BIGENDIAN tests in
-;; builtins.c and optabs.c that are not correct for IBM long double
+;; builtins.cc and optabs.cc that are not correct for IBM long double
 ;; when little-endian.
 (define_expand "signbit<mode>2"
   [(set (match_dup 2)
diff --git a/gcc/config/rs6000/sysv4.h b/gcc/config/rs6000/sysv4.h
index 9522a46..7e2519d 100644
--- a/gcc/config/rs6000/sysv4.h
+++ b/gcc/config/rs6000/sysv4.h
@@ -309,7 +309,7 @@ do {									\
    in bits).  This macro must evaluate to a value equal to or larger
    than STACK_BOUNDARY.
    For the SYSV ABI and variants the alignment of the stack pointer
-   is usually controlled manually in rs6000.c. However, to maintain
+   is usually controlled manually in rs6000.cc. However, to maintain
    alignment across alloca () in all circumstances,
    PREFERRED_STACK_BOUNDARY needs to be set as well.
    This has the additional advantage of allowing a bigger maximum
diff --git a/gcc/config/rs6000/t-linux b/gcc/config/rs6000/t-linux
index aeb7440..4e37125 100644
--- a/gcc/config/rs6000/t-linux
+++ b/gcc/config/rs6000/t-linux
@@ -14,6 +14,6 @@ MULTILIB_OSDIRNAMES := $(subst -linux,le-linux,$(MULTILIB_OSDIRNAMES))
 endif
 endif
 
-rs6000-linux.o: $(srcdir)/config/rs6000/rs6000-linux.c
+rs6000-linux.o: $(srcdir)/config/rs6000/rs6000-linux.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/rs6000/t-linux64 b/gcc/config/rs6000/t-linux64
index 94aebeb..47e0efd 100644
--- a/gcc/config/rs6000/t-linux64
+++ b/gcc/config/rs6000/t-linux64
@@ -31,6 +31,6 @@ MULTILIB_EXTRA_OPTS :=
 MULTILIB_OSDIRNAMES := m64=../lib64$(call if_multiarch,:powerpc64-linux-gnu)
 MULTILIB_OSDIRNAMES += m32=$(if $(wildcard $(shell echo $(SYSTEM_HEADER_DIR))/../../usr/lib32),../lib32,../lib)$(call if_multiarch,:powerpc-linux-gnu)
 
-rs6000-linux.o: $(srcdir)/config/rs6000/rs6000-linux.c
+rs6000-linux.o: $(srcdir)/config/rs6000/rs6000-linux.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/rs6000/t-rs6000 b/gcc/config/rs6000/t-rs6000
index d08deb1..90079ce 100644
--- a/gcc/config/rs6000/t-rs6000
+++ b/gcc/config/rs6000/t-rs6000
@@ -23,28 +23,28 @@ TM_H += $(srcdir)/config/rs6000/rs6000-modes.h
 PASSES_EXTRA += $(srcdir)/config/rs6000/rs6000-passes.def
 EXTRA_GTYPE_DEPS += $(srcdir)/config/rs6000/rs6000-builtins.def
 
-rs6000-pcrel-opt.o: $(srcdir)/config/rs6000/rs6000-pcrel-opt.c
+rs6000-pcrel-opt.o: $(srcdir)/config/rs6000/rs6000-pcrel-opt.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-rs6000-string.o: $(srcdir)/config/rs6000/rs6000-string.c
+rs6000-string.o: $(srcdir)/config/rs6000/rs6000-string.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-rs6000-p8swap.o: $(srcdir)/config/rs6000/rs6000-p8swap.c
+rs6000-p8swap.o: $(srcdir)/config/rs6000/rs6000-p8swap.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-rs6000-d.o: $(srcdir)/config/rs6000/rs6000-d.c
+rs6000-d.o: $(srcdir)/config/rs6000/rs6000-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-rs6000-logue.o: $(srcdir)/config/rs6000/rs6000-logue.c
+rs6000-logue.o: $(srcdir)/config/rs6000/rs6000-logue.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-build/rs6000-gen-builtins.o: $(srcdir)/config/rs6000/rs6000-gen-builtins.c
-build/rbtree.o: $(srcdir)/config/rs6000/rbtree.c
+build/rs6000-gen-builtins.o: $(srcdir)/config/rs6000/rs6000-gen-builtins.cc
+build/rbtree.o: $(srcdir)/config/rs6000/rbtree.cc
 
 build/rs6000-gen-builtins$(build_exeext): build/rs6000-gen-builtins.o \
 					  build/rbtree.o $(BUILD_LIBDEPS)
@@ -53,34 +53,34 @@ build/rs6000-gen-builtins$(build_exeext): build/rs6000-gen-builtins.o \
 
 # TODO: Whenever GNU make 4.3 is the minimum required, we should use
 # grouped targets on this:
-#    rs6000-builtins.c rs6000-builtins.h rs6000-vecdefines.h &: <deps>
+#    rs6000-builtins.cc rs6000-builtins.h rs6000-vecdefines.h &: <deps>
 #       <recipe>
-# For now, the header files depend on rs6000-builtins.c, which avoids
-# races because the .c file is closed last in rs6000-gen-builtins.c.
-rs6000-builtins.c: build/rs6000-gen-builtins$(build_exeext) \
+# For now, the header files depend on rs6000-builtins.cc, which avoids
+# races because the .c file is closed last in rs6000-gen-builtins.cc.
+rs6000-builtins.cc: build/rs6000-gen-builtins$(build_exeext) \
 		   $(srcdir)/config/rs6000/rs6000-builtins.def \
 		   $(srcdir)/config/rs6000/rs6000-overload.def
 	$(RUN_GEN) ./build/rs6000-gen-builtins$(build_exeext) \
 		$(srcdir)/config/rs6000/rs6000-builtins.def \
 		$(srcdir)/config/rs6000/rs6000-overload.def rs6000-builtins.h \
-		rs6000-builtins.c rs6000-vecdefines.h
+		rs6000-builtins.cc rs6000-vecdefines.h
 
-rs6000-builtins.h: rs6000-builtins.c
+rs6000-builtins.h: rs6000-builtins.cc
 
 rs6000.o: rs6000-builtins.h
 
 EXTRA_HEADERS += rs6000-vecdefines.h
-rs6000-vecdefines.h: rs6000-builtins.c
+rs6000-vecdefines.h: rs6000-builtins.cc
 
-rs6000-builtins.o: rs6000-builtins.c
+rs6000-builtins.o: rs6000-builtins.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-rs6000-call.o: $(srcdir)/config/rs6000/rs6000-call.c rs6000-builtins.h
+rs6000-call.o: $(srcdir)/config/rs6000/rs6000-call.cc rs6000-builtins.h
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-rs6000-c.o: $(srcdir)/config/rs6000/rs6000-c.c rs6000-builtins.h
+rs6000-c.o: $(srcdir)/config/rs6000/rs6000-c.cc rs6000-builtins.h
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/rs6000/x-darwin b/gcc/config/rs6000/x-darwin
index 9d92ef5..908c60e 100644
--- a/gcc/config/rs6000/x-darwin
+++ b/gcc/config/rs6000/x-darwin
@@ -1,3 +1,3 @@
-host-ppc-darwin.o : $(srcdir)/config/rs6000/host-darwin.c
+host-ppc-darwin.o : $(srcdir)/config/rs6000/host-darwin.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/rs6000/x-darwin64 b/gcc/config/rs6000/x-darwin64
index 0932771..5e9655c 100644
--- a/gcc/config/rs6000/x-darwin64
+++ b/gcc/config/rs6000/x-darwin64
@@ -1,3 +1,3 @@
-host-ppc64-darwin.o : $(srcdir)/config/rs6000/host-ppc64-darwin.c
+host-ppc64-darwin.o : $(srcdir)/config/rs6000/host-ppc64-darwin.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/rs6000/x-rs6000 b/gcc/config/rs6000/x-rs6000
index 9e31f24..afd39ce 100644
--- a/gcc/config/rs6000/x-rs6000
+++ b/gcc/config/rs6000/x-rs6000
@@ -1,3 +1,3 @@
-driver-rs6000.o : $(srcdir)/config/rs6000/driver-rs6000.c \
+driver-rs6000.o : $(srcdir)/config/rs6000/driver-rs6000.cc \
   $(CONFIG_H) $(SYSTEM_H) $(TM_H) coretypes.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/rs6000/xcoff.h b/gcc/config/rs6000/xcoff.h
index 7471517..cd0f99c 100644
--- a/gcc/config/rs6000/xcoff.h
+++ b/gcc/config/rs6000/xcoff.h
@@ -30,7 +30,7 @@
 /* Define the magic numbers that we recognize as COFF.
  
     AIX 4.3 adds U803XTOCMAGIC (0757) for 64-bit objects and AIX V5 adds
-    U64_TOCMAGIC (0767), but collect2.c does not include files in the
+    U64_TOCMAGIC (0767), but collect2.cc does not include files in the
     correct order to conditionally define the symbolic name in this macro.
  
     The AIX linker accepts import/export files as object files,
@@ -184,7 +184,7 @@
 #define ASM_OUTPUT_LABELREF(FILE,NAME)	\
   asm_fprintf ((FILE), "%U%s", rs6000_xcoff_strip_dollar (NAME))
 
-/* This is how to output an internal label prefix.  rs6000.c uses this
+/* This is how to output an internal label prefix.  rs6000.cc uses this
    when generating traceback tables.  */
 
 #define ASM_OUTPUT_INTERNAL_LABEL_PREFIX(FILE,PREFIX)   \
diff --git a/gcc/config/rx/rx.cc b/gcc/config/rx/rx.cc
index 585542c..ba82482 100644
--- a/gcc/config/rx/rx.cc
+++ b/gcc/config/rx/rx.cc
@@ -2671,7 +2671,7 @@ rx_expand_builtin (tree exp,
 }
 
 /* Place an element into a constructor or destructor section.
-   Like default_ctor_section_asm_out_constructor in varasm.c
+   Like default_ctor_section_asm_out_constructor in varasm.cc
    except that it uses .init_array (or .fini_array) and it
    handles constructor priorities.  */
 
diff --git a/gcc/config/s390/constraints.md b/gcc/config/s390/constraints.md
index 70bc9d1..4854f34 100644
--- a/gcc/config/s390/constraints.md
+++ b/gcc/config/s390/constraints.md
@@ -1,7 +1,7 @@
 ;; Constraints definitions belonging to the gcc backend for IBM S/390.
 ;; Copyright (C) 2006-2022 Free Software Foundation, Inc.
 ;; Written by Wolfgang Gellerich, using code and information found in
-;; files s390.md, s390.h, and s390.c.
+;; files s390.md, s390.h, and s390.cc.
 ;;
 ;; This file is part of GCC.
 ;;
@@ -595,11 +595,11 @@
 
 ;; This constraint must behave like "i", in particular, the matching values
 ;; must never be placed into registers or memory by
-;; cfgexpand.c:expand_asm_stmt.  It could be straightforward to start its name
-;; with a letter from genpreds.c:const_int_constraints, however it would
+;; cfgexpand.cc:expand_asm_stmt.  It could be straightforward to start its name
+;; with a letter from genpreds.cc:const_int_constraints, however it would
 ;; require using (match_code "const_int"), which is infeasible.  To achieve the
 ;; same effect, that is, setting maybe_allows_reg and maybe_allows_mem to false
-;; in genpreds.c:add_constraint, we explicitly exclude reg, subreg and mem
+;; in genpreds.cc:add_constraint, we explicitly exclude reg, subreg and mem
 ;; codes.
 (define_constraint "jdd"
   "A constant operand that fits into the data section.
diff --git a/gcc/config/s390/driver-native.cc b/gcc/config/s390/driver-native.cc
index 3d9fb6c..48524c4 100644
--- a/gcc/config/s390/driver-native.cc
+++ b/gcc/config/s390/driver-native.cc
@@ -24,7 +24,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "coretypes.h"
 #include "tm.h"
 
-/* This will be called by the spec parser in gcc.c when it sees
+/* This will be called by the spec parser in gcc.cc when it sees
    a %:local_cpu_detect(args) construct.  Currently it will be called
    with either "arch" or "tune" as argument depending on if -march=native
    or -mtune=native is to be substituted.
diff --git a/gcc/config/s390/htmxlintrin.h b/gcc/config/s390/htmxlintrin.h
index e5ac912..51d0b55 100644
--- a/gcc/config/s390/htmxlintrin.h
+++ b/gcc/config/s390/htmxlintrin.h
@@ -36,7 +36,7 @@ extern "C" {
 /* FIXME: __TM_simple_begin and __TM_begin should be marked
    __always_inline__ as well but this currently produces an error
    since the tbegin builtins are "returns_twice" and setjmp_call_p
-   (calls.c) therefore identifies the functions as calling setjmp.
+   (calls.cc) therefore identifies the functions as calling setjmp.
    The tree inliner currently refuses to inline functions calling
    setjmp.  */
 
diff --git a/gcc/config/s390/s390-builtins.def b/gcc/config/s390/s390-builtins.def
index dd89156..c7e893b 100644
--- a/gcc/config/s390/s390-builtins.def
+++ b/gcc/config/s390/s390-builtins.def
@@ -412,7 +412,7 @@ B_DEF      (s390_vec_splat_s32,         vec_splatsv4si,     0,
 B_DEF      (s390_vec_splat_u64,         vec_splatsv2di,     0,                  B_VX,               O1_U16,             BT_FN_UV2DI_USHORT)
 B_DEF      (s390_vec_splat_s64,         vec_splatsv2di,     0,                  B_VX,               O1_S16,             BT_FN_V2DI_SHORT)
 
-/* First two operands are swapped in s390-c.c */
+/* First two operands are swapped in s390-c.cc */
 OB_DEF     (s390_vec_insert,            s390_vec_insert_s8, s390_vec_insert_dbl,B_VX,               BT_FN_OV4SI_INT_OV4SI_INT)
 OB_DEF_VAR (s390_vec_insert_s8,         s390_vlvgb,         0,                  O3_ELEM,            BT_OV_V16QI_SCHAR_V16QI_INT)
 OB_DEF_VAR (s390_vec_insert_u8,         s390_vlvgb,         0,                  O3_ELEM,            BT_OV_UV16QI_UCHAR_UV16QI_INT)
@@ -497,7 +497,7 @@ B_DEF      (s390_vllezf_flt,            vec_insert_and_zerov4sf,0,
 B_DEF      (s390_vllezg,                vec_insert_and_zerov2di,0,              B_VX,               0,                  BT_FN_UV2DI_ULONGLONGCONSTPTR)
 B_DEF      (s390_vllezg_dbl,            vec_insert_and_zerov2df,0,              B_INT | B_VX,       0,                  BT_FN_V2DF_DBLCONSTPTR)
 
-/* The 2nd operand will by translated in s390-c.c from 64, 128, 256, ... to 0, 1, 2, ... */
+/* The 2nd operand will by translated in s390-c.cc from 64, 128, 256, ... to 0, 1, 2, ... */
 OB_DEF     (s390_vec_load_bndry,        s390_vec_load_bndry_s8,s390_vec_load_bndry_dbl,B_VX,        BT_FN_OV4SI_INTCONSTPTR_INT)
 OB_DEF_VAR (s390_vec_load_bndry_s8,     s390_vlbb,          0,                  O2_U16,             BT_OV_V16QI_SCHARCONSTPTR_USHORT)
 OB_DEF_VAR (s390_vec_load_bndry_u8,     s390_vlbb,          0,                  O2_U16,             BT_OV_UV16QI_UCHARCONSTPTR_USHORT)
@@ -516,7 +516,7 @@ OB_DEF     (s390_vec_load_pair,         s390_vec_load_pair_s64,s390_vec_load_pai
 OB_DEF_VAR (s390_vec_load_pair_s64,     MAX,                0,                  0,                  BT_OV_V2DI_LONGLONG_LONGLONG)            /* vlvgp */
 OB_DEF_VAR (s390_vec_load_pair_u64,     MAX,                0,                  0,                  BT_OV_UV2DI_ULONGLONG_ULONGLONG)         /* vlvgp */
 
-/* First two operands are swapped in s390-c.c */
+/* First two operands are swapped in s390-c.cc */
 OB_DEF     (s390_vec_load_len,          s390_vec_load_len_s8,s390_vec_load_len_dbl,B_VX,            BT_FN_OV4SI_INTCONSTPTR_UINT)
 OB_DEF_VAR (s390_vec_load_len_s8,       s390_vll,           0,                  0,                  BT_OV_V16QI_SCHARCONSTPTR_UINT)
 OB_DEF_VAR (s390_vec_load_len_u8,       s390_vll,           0,                  0,                  BT_OV_UV16QI_UCHARCONSTPTR_UINT)
@@ -702,7 +702,7 @@ OB_DEF_VAR (s390_vec_scatter_element_dbl,s390_vsceg,        0,
 B_DEF      (s390_vscef,                 vec_scatter_elementv4si,0,              B_VX,               O4_U2,              BT_FN_VOID_UV4SI_UV4SI_UINTPTR_ULONGLONG)
 B_DEF      (s390_vsceg,                 vec_scatter_elementv2di,0,              B_VX,               O4_U1,              BT_FN_VOID_UV2DI_UV2DI_ULONGLONGPTR_ULONGLONG)
 
-/* First two operands are swapped in s390-c.c */
+/* First two operands are swapped in s390-c.cc */
 OB_DEF     (s390_vec_sel,               s390_vec_sel_b8_a,  s390_vec_sel_dbl_b, B_VX,               BT_FN_OV4SI_OV4SI_OV4SI_OV4SI)
 OB_DEF_VAR (s390_vec_sel_b8_a,          s390_vselb,         0,                  0,                  BT_OV_BV16QI_BV16QI_BV16QI_UV16QI)
 OB_DEF_VAR (s390_vec_sel_b8_b,          s390_vselb,         0,                  0,                  BT_OV_BV16QI_BV16QI_BV16QI_BV16QI)
diff --git a/gcc/config/s390/s390-builtins.h b/gcc/config/s390/s390-builtins.h
index 091d690..8809f0e 100644
--- a/gcc/config/s390/s390-builtins.h
+++ b/gcc/config/s390/s390-builtins.h
@@ -20,7 +20,7 @@
    <http://www.gnu.org/licenses/>.  */
 
 /* This files contains data structure definitions which can be used by
-   s390-builtins.c as well as s390-c.c.  Since the latter is
+   s390-builtins.cc as well as s390-c.cc.  Since the latter is
    considered to be part of the front-end we have to be careful not
    to use any of tree and rtx like data structures.  */
 
diff --git a/gcc/config/s390/s390-c.cc b/gcc/config/s390/s390-c.cc
index 6000184..569c4a4 100644
--- a/gcc/config/s390/s390-c.cc
+++ b/gcc/config/s390/s390-c.cc
@@ -20,7 +20,7 @@
    along with GCC; see the file COPYING3.  If not see
    <http://www.gnu.org/licenses/>.
 
-   Based on gcc/config/rs6000/rs6000-c.c.
+   Based on gcc/config/rs6000/rs6000-c.cc.
 
    In GCC terms this file belongs to the frontend.  It will be
    compiled with -DIN_GCC_FRONTEND.  With that rtl.h cannot be
diff --git a/gcc/config/s390/s390-opts.h b/gcc/config/s390/s390-opts.h
index a374329..1ec8463 100644
--- a/gcc/config/s390/s390-opts.h
+++ b/gcc/config/s390/s390-opts.h
@@ -23,7 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 /* Which processor to generate code or schedule for. The `cpu' attribute
    defines a list that mirrors this list, so changes to s390.md must be
    made at the same time.  The enumeration must also be kept in sync with
-   `processor_table' and `processor_flags_table' in s390.c (the enumeration
+   `processor_table' and `processor_flags_table' in s390.cc (the enumeration
    values are used as indices into these tables).  */
 
 enum processor_type
diff --git a/gcc/config/s390/s390-protos.h b/gcc/config/s390/s390-protos.h
index a9d21c3..e625159 100644
--- a/gcc/config/s390/s390-protos.h
+++ b/gcc/config/s390/s390-protos.h
@@ -31,13 +31,13 @@ extern int s390_float_const_zero_p (rtx value);
 extern bool s390_check_symref_alignment (rtx addr, HOST_WIDE_INT alignment);
 
 
-/* In s390-common.c.  */
+/* In s390-common.cc.  */
 extern bool s390_handle_option (struct gcc_options *opts ATTRIBUTE_UNUSED,
 				struct gcc_options *opts_set ATTRIBUTE_UNUSED,
 				const struct cl_decoded_option *decoded,
 				location_t loc);
 
-/* Declare functions in s390.c.  */
+/* Declare functions in s390.cc.  */
 
 extern HOST_WIDE_INT s390_initial_elimination_offset (int, int);
 extern void s390_emit_prologue (void);
@@ -168,14 +168,14 @@ extern void s390_indirect_branch_via_thunk (unsigned int regno,
 extern void s390_indirect_branch_via_inline_thunk (rtx execute_target);
 #endif /* RTX_CODE */
 
-/* s390-c.c routines */
+/* s390-c.cc routines */
 extern void s390_cpu_cpp_builtins (struct cpp_reader *);
 extern void s390_register_target_pragmas (void);
 
-/* Routines for s390-c.c */
+/* Routines for s390-c.cc */
 extern bool s390_const_operand_ok (tree, int, int, tree);
 
-/* s390-d.c routines */
+/* s390-d.cc routines */
 extern void s390_d_target_versions (void);
 extern void s390_d_register_target_info (void);
 
diff --git a/gcc/config/s390/s390.cc b/gcc/config/s390/s390.cc
index 056002e..7fc1901 100644
--- a/gcc/config/s390/s390.cc
+++ b/gcc/config/s390/s390.cc
@@ -651,9 +651,9 @@ s390_init_builtins (void)
   tree noreturn_attr = tree_cons (get_identifier ("noreturn"), NULL, NULL);
   tree c_uint64_type_node;
 
-  /* The uint64_type_node from tree.c is not compatible to the C99
+  /* The uint64_type_node from tree.cc is not compatible to the C99
      uint64_t data type.  What we want is c_uint64_type_node from
-     c-common.c.  But since backend code is not supposed to interface
+     c-common.cc.  But since backend code is not supposed to interface
      with the frontend we recreate it here.  */
   if (TARGET_64BIT)
     c_uint64_type_node = long_unsigned_type_node;
@@ -4769,7 +4769,7 @@ s390_expand_plus_operand (rtx target, rtx src,
 	}
 
       /* According to the way these invalid addresses are generated
-	 in reload.c, it should never happen (at least on s390) that
+	 in reload.cc, it should never happen (at least on s390) that
 	 *neither* of the PLUS components, after find_replacements
 	 was applied, is an address register.  */
       if (sum1 == scratch && sum2 == scratch)
@@ -7509,7 +7509,7 @@ s390_expand_atomic (machine_mode mode, enum rtx_code code,
 					       NULL_RTX, 1, OPTAB_DIRECT), 1);
 }
 
-/* This is called from dwarf2out.c via TARGET_ASM_OUTPUT_DWARF_DTPREL.
+/* This is called from dwarf2out.cc via TARGET_ASM_OUTPUT_DWARF_DTPREL.
    We need to emit DTP-relative relocations.  */
 
 static void s390_output_dwarf_dtprel (FILE *, int, rtx) ATTRIBUTE_UNUSED;
@@ -15812,7 +15812,7 @@ s390_valid_target_attribute_inner_p (tree args,
       int num_pragma_values;
       int i;
 
-      /* Note: attribs.c:decl_attributes prepends the values from
+      /* Note: attribs.cc:decl_attributes prepends the values from
 	 current_target_pragma to the list of target attributes.  To determine
 	 whether we're looking at a value of the attribute or the pragma we
 	 assume that the first [list_length (current_target_pragma)] values in
@@ -15933,7 +15933,7 @@ s390_valid_target_attribute_inner_p (tree args,
 	  if (cl_options[opt].cl_uinteger)
 	    {
 	      /* Unsigned integer argument.  Code based on the function
-		 decode_cmdline_option () in opts-common.c.  */
+		 decode_cmdline_option () in opts-common.cc.  */
 	      value = integral_argument (p + opt_len);
 	    }
 	  else
diff --git a/gcc/config/s390/s390.h b/gcc/config/s390/s390.h
index 85733c3..5a64048 100644
--- a/gcc/config/s390/s390.h
+++ b/gcc/config/s390/s390.h
@@ -404,7 +404,7 @@ extern const char *s390_host_detect_local_cpu (int argc, const char **argv);
 #define DOUBLE_TYPE_SIZE 64
 #define LONG_DOUBLE_TYPE_SIZE (TARGET_LONG_DOUBLE_128 ? 128 : 64)
 
-/* Work around target_flags dependency in ada/targtyps.c.  */
+/* Work around target_flags dependency in ada/targtyps.cc.  */
 #define WIDEST_HARDWARE_FP_SIZE 64
 
 /* We use "unsigned char" as default.  */
@@ -817,7 +817,7 @@ CUMULATIVE_ARGS;
 
 /* Try a machine-dependent way of reloading an illegitimate address
    operand.  If we find one, push the reload and jump to WIN.  This
-   macro is used in only one place: `find_reloads_address' in reload.c.  */
+   macro is used in only one place: `find_reloads_address' in reload.cc.  */
 #define LEGITIMIZE_RELOAD_ADDRESS(AD, MODE, OPNUM, TYPE, IND, WIN)	\
   do {									\
     rtx new_rtx = legitimize_reload_address ((AD), (MODE),		\
@@ -829,7 +829,7 @@ CUMULATIVE_ARGS;
       }									\
   } while (0)
 
-/* Helper macro for s390.c and s390.md to check for symbolic constants.  */
+/* Helper macro for s390.cc and s390.md to check for symbolic constants.  */
 #define SYMBOLIC_CONST(X)						\
   (GET_CODE (X) == SYMBOL_REF						\
    || GET_CODE (X) == LABEL_REF						\
@@ -1213,7 +1213,7 @@ struct GTY(()) machine_function
 #define TARGET_INDIRECT_BRANCH_TABLE s390_indirect_branch_table
 
 #ifdef GENERATOR_FILE
-/* gencondmd.c is built before insn-flags.h.  Use an arbitrary opaque value
+/* gencondmd.cc is built before insn-flags.h.  Use an arbitrary opaque value
    that cannot be optimized away by gen_insn.  */
 #define HAVE_TF(icode) TARGET_HARD_FLOAT
 #else
diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index 4d25666..e3ccbac 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -1949,7 +1949,7 @@
 
 ; Splitters for loading TLS pointer from UNSPEC_GET_TP.
 ; UNSPEC_GET_TP is used instead of %a0:P, since the latter is a hard register,
-; and those are not handled by Partial Redundancy Elimination (gcse.c), which
+; and those are not handled by Partial Redundancy Elimination (gcse.cc), which
 ; results in generation of redundant thread pointer loads.
 
 (define_insn_and_split "*get_tp_31"
@@ -11031,7 +11031,7 @@
   [(set_attr "op_type" "RSY")
    (set_attr "type" "sem")])
 
-;; For SImode and larger, the optabs.c code will do just fine in
+;; For SImode and larger, the optabs.cc code will do just fine in
 ;; expanding a compare-and-swap loop.  For QI/HImode, we can do
 ;; better by expanding our own loop.
 
@@ -11978,7 +11978,7 @@
    (clobber (reg:TI 30)) (clobber (reg:TI 52))
    (clobber (reg:TI 31)) (clobber (reg:TI 53))]
 ; CONST_OK_FOR_CONSTRAINT_P does not work with D constraint since D is
-; not supposed to be used for immediates (see genpreds.c).
+; not supposed to be used for immediates (see genpreds.cc).
   "TARGET_VX && INTVAL (operands[0]) >= 0 && INTVAL (operands[0]) <= 0xffff"
   "tbegin\t%1,%x0"
   [(set_attr "op_type" "SIL")])
@@ -12006,7 +12006,7 @@
    (clobber (reg:DF 30))
    (clobber (reg:DF 31))]
 ; CONST_OK_FOR_CONSTRAINT_P does not work with D constraint since D is
-; not supposed to be used for immediates (see genpreds.c).
+; not supposed to be used for immediates (see genpreds.cc).
   "TARGET_HTM && INTVAL (operands[0]) >= 0 && INTVAL (operands[0]) <= 0xffff"
   "tbegin\t%1,%x0"
   [(set_attr "op_type" "SIL")])
diff --git a/gcc/config/s390/t-s390 b/gcc/config/s390/t-s390
index 07896eb..767df10 100644
--- a/gcc/config/s390/t-s390
+++ b/gcc/config/s390/t-s390
@@ -20,13 +20,13 @@ TM_H += $(srcdir)/config/s390/s390-builtins.def
 TM_H += $(srcdir)/config/s390/s390-builtin-types.def
 PASSES_EXTRA += $(srcdir)/config/s390/s390-passes.def
 
-s390-c.o: $(srcdir)/config/s390/s390-c.c \
+s390-c.o: $(srcdir)/config/s390/s390-c.cc \
   $(srcdir)/config/s390/s390-protos.h $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(TM_H) $(TREE_H) $(TM_P_H) $(FLAGS_H) $(C_COMMON_H) $(GGC_H) \
   $(TARGET_H) $(TARGET_DEF_H) $(CPPLIB_H) $(C_PRAGMA_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/s390/s390-c.c
+		$(srcdir)/config/s390/s390-c.cc
 
-s390-d.o: $(srcdir)/config/s390/s390-d.c
+s390-d.o: $(srcdir)/config/s390/s390-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/s390/vx-builtins.md b/gcc/config/s390/vx-builtins.md
index caee417..d513079 100644
--- a/gcc/config/s390/vx-builtins.md
+++ b/gcc/config/s390/vx-builtins.md
@@ -514,7 +514,7 @@
 ; implemented as: op0 = (op1 & op3) | (op2 & ~op3)
 
 ; Used to expand the vec_sel builtin. Operands op1 and op2 already got
-; swapped in s390-c.c when we get here.
+; swapped in s390-c.cc when we get here.
 
 (define_insn "vsel<mode>"
   [(set (match_operand:V_HW                      0 "register_operand" "=v")
diff --git a/gcc/config/s390/x-native b/gcc/config/s390/x-native
index b33c8b6..d4c950d 100644
--- a/gcc/config/s390/x-native
+++ b/gcc/config/s390/x-native
@@ -1,3 +1,3 @@
-driver-native.o : $(srcdir)/config/s390/driver-native.c \
+driver-native.o : $(srcdir)/config/s390/driver-native.cc \
   $(CONFIG_H) $(SYSTEM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/sh/divtab-sh4-300.cc b/gcc/config/sh/divtab-sh4-300.cc
index 4026fb1..d9af737 100644
--- a/gcc/config/sh/divtab-sh4-300.cc
+++ b/gcc/config/sh/divtab-sh4-300.cc
@@ -33,7 +33,7 @@ main ()
   int i, j;
   double q, r, err, max_err = 0, max_s_err = 0;
 
-  puts("/* This table has been generated by divtab-sh4.c.  */");
+  puts("/* This table has been generated by divtab-sh4.cc.  */");
   puts ("\t.balign 4");
   for (i = -128; i < 128; i++)
     {
diff --git a/gcc/config/sh/divtab-sh4.cc b/gcc/config/sh/divtab-sh4.cc
index 0700fae..2c6d1f2 100644
--- a/gcc/config/sh/divtab-sh4.cc
+++ b/gcc/config/sh/divtab-sh4.cc
@@ -32,7 +32,7 @@ main ()
   int i, j;
   double q, r, err, max_err = 0, max_s_err = 0;
 
-  puts("/* This table has been generated by divtab-sh4.c.  */");
+  puts("/* This table has been generated by divtab-sh4.cc.  */");
   puts ("\t.balign 4");
   puts ("LOCAL(div_table_clz):");
   /* output some dummy number for 1/0.  */
diff --git a/gcc/config/sh/divtab.cc b/gcc/config/sh/divtab.cc
index 10f7429..30d57f2 100644
--- a/gcc/config/sh/divtab.cc
+++ b/gcc/config/sh/divtab.cc
@@ -167,7 +167,7 @@ main ()
       calc_defect (x_med, constant, factor);
       calc_defect (x_high, constant, factor);
     }
-    printf ("/* This table has been generated by divtab.c .\n");
+    printf ("/* This table has been generated by divtab.cc .\n");
     printf ("Defects for bias %d:\n", BIAS);
     printf ("   Max defect: %e at %e\n", max_defect, max_defect_x);
     printf ("   Min defect: %e at %e\n", min_defect, min_defect_x);
diff --git a/gcc/config/sh/elf.h b/gcc/config/sh/elf.h
index ffddd8d..afb3bc3 100644
--- a/gcc/config/sh/elf.h
+++ b/gcc/config/sh/elf.h
@@ -18,7 +18,7 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-/* Let sh.c know this is ELF.  */
+/* Let sh.cc know this is ELF.  */
 #undef TARGET_ELF
 #define TARGET_ELF 1
 
diff --git a/gcc/config/sh/sh-protos.h b/gcc/config/sh/sh-protos.h
index 0fc37a9..44a4bdf 100644
--- a/gcc/config/sh/sh-protos.h
+++ b/gcc/config/sh/sh-protos.h
@@ -39,7 +39,7 @@ enum sh_function_kind {
 extern rtx sh_fsca_sf2int (void);
 extern rtx sh_fsca_int2sf (void);
 
-/* Declare functions defined in sh.c and used in templates.  */
+/* Declare functions defined in sh.cc and used in templates.  */
 extern bool sh_lra_p (void);
 
 extern const char *output_branch (int, rtx_insn *, rtx *);
diff --git a/gcc/config/sh/sh.cc b/gcc/config/sh/sh.cc
index ca096ad..dd8bce4 100644
--- a/gcc/config/sh/sh.cc
+++ b/gcc/config/sh/sh.cc
@@ -640,7 +640,7 @@ static const struct attribute_spec sh_attribute_table[] =
 #define SYMBOL_FLAG_FUNCVEC_FUNCTION	(SYMBOL_FLAG_MACH_DEP << 0)
 
 /* The tas.b instruction sets the 7th bit in the byte, i.e. 0x80.  This value
-   is used by optabs.c atomic op expansion code as well as in sync.md.  */
+   is used by optabs.cc atomic op expansion code as well as in sync.md.  */
 #undef TARGET_ATOMIC_TEST_AND_SET_TRUEVAL
 #define TARGET_ATOMIC_TEST_AND_SET_TRUEVAL 0x80
 
@@ -8123,7 +8123,7 @@ sh_struct_value_rtx (tree fndecl, int incoming ATTRIBUTE_UNUSED)
    mode like PROMOTE_MODE does.
    ??? PROMOTE_MODE is ignored for non-scalar types.  The set of types
    tested here has to be kept in sync with the one in
-   explow.c:promote_mode.  */
+   explow.cc:promote_mode.  */
 static rtx
 sh_function_value (const_tree valtype,
 		   const_tree fn_decl_or_type,
@@ -11823,7 +11823,7 @@ sh_remove_reg_dead_or_unused_notes (rtx_insn* i, int regno)
 
 /* Given an insn check if it contains any post/pre inc/dec mem operands and
    add the REG_INC notes accordingly.
-   FIXME: This function is very similar to lra.c (add_auto_inc_notes).
+   FIXME: This function is very similar to lra.cc (add_auto_inc_notes).
    FIXME: This function is currently used by peephole2 patterns because
 	  the peephole2 pass does not preserve REG_INC notes.  If the notes
 	  are dropped the following passes will do wrong things.  */
diff --git a/gcc/config/sh/sh.h b/gcc/config/sh/sh.h
index a2497ab..4f209d2 100644
--- a/gcc/config/sh/sh.h
+++ b/gcc/config/sh/sh.h
@@ -24,8 +24,8 @@ along with GCC; see the file COPYING3.  If not see
 
 #include "config/vxworks-dummy.h"
 
-/* Unfortunately, insn-attrtab.c doesn't include insn-codes.h.  We can't
-   include it here, because bconfig.h is also included by gencodes.c .  */
+/* Unfortunately, insn-attrtab.cc doesn't include insn-codes.h.  We can't
+   include it here, because bconfig.h is also included by gencodes.cc .  */
 /* ??? No longer true.  */
 extern int code_for_indirect_jump_scratch;
 
@@ -433,7 +433,7 @@ extern const sh_atomic_model& selected_atomic_model (void);
 #define MIN_UNITS_PER_WORD 4
 
 /* Scaling factor for Dwarf data offsets for CFI information.
-   The dwarf2out.c default would use -UNITS_PER_WORD.  */
+   The dwarf2out.cc default would use -UNITS_PER_WORD.  */
 #define DWARF_CIE_DATA_ALIGNMENT -4
 
 /* Width in bits of a pointer.
@@ -1284,7 +1284,7 @@ extern bool current_function_interrupt;
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 #define REGNO_OK_FOR_BASE_P(REGNO) \
   (GENERAL_OR_AP_REGISTER_P (REGNO) \
diff --git a/gcc/config/sh/t-sh b/gcc/config/sh/t-sh
index 37de2bb..dd5652e 100644
--- a/gcc/config/sh/t-sh
+++ b/gcc/config/sh/t-sh
@@ -20,10 +20,10 @@ sh-mem.o: $(srcdir)/config/sh/sh-mem.cc \
   $(CONFIG_H) $(SYSTEM_H) $(TREE_H) $(TM_H) $(TM_P_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
-sh-c.o: $(srcdir)/config/sh/sh-c.c \
+sh-c.o: $(srcdir)/config/sh/sh-c.cc \
   $(CONFIG_H) $(SYSTEM_H) $(TREE_H) $(TM_H) $(TM_P_H) coretypes.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/sh/sh-c.c
+		$(srcdir)/config/sh/sh-c.cc
 
 sh_treg_combine.o: $(srcdir)/config/sh/sh_treg_combine.cc \
   $(CONFIG_H) $(SYSTEM_H) $(TREE_H) $(TM_H) $(TM_P_H) coretypes.h
diff --git a/gcc/config/sol2-protos.h b/gcc/config/sol2-protos.h
index b81b25b..6307e13 100644
--- a/gcc/config/sol2-protos.h
+++ b/gcc/config/sol2-protos.h
@@ -18,7 +18,7 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-/* In sol2.c.  */
+/* In sol2.cc.  */
 extern void solaris_assemble_visibility (tree, int);
 extern void solaris_elf_asm_comdat_section (const char *, unsigned int, tree);
 extern void solaris_file_end (void);
@@ -26,8 +26,8 @@ extern void solaris_insert_attributes (tree, tree *);
 extern void solaris_output_init_fini (FILE *, tree);
 extern void solaris_override_options (void);
 
-/* In sol2-c.c.  */
+/* In sol2-c.cc.  */
 extern void solaris_register_pragmas (void);
 
-/* In sol2-cxx.c.  */
+/* In sol2-cxx.cc.  */
 extern tree solaris_cxx_decl_mangling_context (const_tree);
diff --git a/gcc/config/sol2.h b/gcc/config/sol2.h
index 5339956..e22c70c 100644
--- a/gcc/config/sol2.h
+++ b/gcc/config/sol2.h
@@ -449,7 +449,7 @@ along with GCC; see the file COPYING3.  If not see
   "%{no-pie:} %{pie:%e-pie is not supported in this configuration} "
 #endif
 
-/* collect2.c can only parse GNU nm -n output.  Solaris nm needs -png to
+/* collect2.cc can only parse GNU nm -n output.  Solaris nm needs -png to
    produce the same format.  */
 #define NM_FLAGS "-png"
 
@@ -466,7 +466,7 @@ along with GCC; see the file COPYING3.  If not see
   { "fini",      0, 0, true,  false,  false, false, NULL, NULL }
 
 /* Solaris-specific #pragmas are implemented on top of attributes.  Hook in
-   the bits from config/sol2.c.  */
+   the bits from config/sol2.cc.  */
 #define SUBTARGET_INSERT_ATTRIBUTES solaris_insert_attributes
 #define SUBTARGET_ATTRIBUTE_TABLE SOLARIS_ATTRIBUTE_TABLE
 
diff --git a/gcc/config/sparc/driver-sparc.cc b/gcc/config/sparc/driver-sparc.cc
index 719427b..73088e9 100644
--- a/gcc/config/sparc/driver-sparc.cc
+++ b/gcc/config/sparc/driver-sparc.cc
@@ -89,7 +89,7 @@ static const struct cpu_names {
 #include <kstat.h>
 #endif
 
-/* This will be called by the spec parser in gcc.c when it sees
+/* This will be called by the spec parser in gcc.cc when it sees
    a %:local_cpu_detect(args) construct.  Currently it will be called
    with either "cpu" or "tune" as argument depending on if -mcpu=native
    or -mtune=native is to be substituted.
diff --git a/gcc/config/sparc/freebsd.h b/gcc/config/sparc/freebsd.h
index fabfd68..98319c5 100644
--- a/gcc/config/sparc/freebsd.h
+++ b/gcc/config/sparc/freebsd.h
@@ -56,8 +56,8 @@ along with GCC; see the file COPYING3.  If not see
 /************************[  Target stuff  ]***********************************/
 
 /* Define the actual types of some ANSI-mandated types.  
-   Needs to agree with <machine/ansi.h>.  GCC defaults come from c-decl.c,
-   c-common.c, and config/<arch>/<arch>.h.  */
+   Needs to agree with <machine/ansi.h>.  GCC defaults come from c-decl.cc,
+   c-common.cc, and config/<arch>/<arch>.h.  */
 
 /* Earlier headers may get this wrong for FreeBSD.
    We use the GCC defaults instead.  */
diff --git a/gcc/config/sparc/sparc-protos.h b/gcc/config/sparc/sparc-protos.h
index 6819f6d..f9e1c74 100644
--- a/gcc/config/sparc/sparc-protos.h
+++ b/gcc/config/sparc/sparc-protos.h
@@ -112,7 +112,7 @@ unsigned int sparc_regmode_natural_size (machine_mode);
 
 extern rtl_opt_pass *make_pass_work_around_errata (gcc::context *);
 
-/* Routines implemented in sparc-d.c  */
+/* Routines implemented in sparc-d.cc  */
 extern void sparc_d_target_versions (void);
 extern void sparc_d_register_target_info (void);
 
diff --git a/gcc/config/sparc/sparc.cc b/gcc/config/sparc/sparc.cc
index 5331824..bb4ce88 100644
--- a/gcc/config/sparc/sparc.cc
+++ b/gcc/config/sparc/sparc.cc
@@ -1,4 +1,4 @@
-/* Subroutines for insn-output.c for SPARC.
+/* Subroutines for insn-output.cc for SPARC.
    Copyright (C) 1987-2022 Free Software Foundation, Inc.
    Contributed by Michael Tiemann (tiemann@cygnus.com)
    64-bit SPARC-V9 support by Michael Tiemann, Jim Wilson, and Doug Evans,
@@ -12376,7 +12376,7 @@ sparc_output_mi_thunk (FILE *file, tree thunk_fndecl ATTRIBUTE_UNUSED,
 	 output_sibcall that we are in a leaf function.  */
       sparc_leaf_function_p = crtl->uses_only_leaf_regs = 1;
 
-      /* This will cause final.c to invoke leaf_renumber_regs so we
+      /* This will cause final.cc to invoke leaf_renumber_regs so we
 	 must behave as if we were in a not-yet-leafified function.  */
       int_arg_first = SPARC_INCOMING_INT_ARG_FIRST;
     }
@@ -12581,7 +12581,7 @@ sparc_asan_shadow_offset (void)
   return TARGET_ARCH64 ? (HOST_WIDE_INT_1 << 43) : (HOST_WIDE_INT_1 << 29);
 }
 
-/* This is called from dwarf2out.c via TARGET_ASM_OUTPUT_DWARF_DTPREL.
+/* This is called from dwarf2out.cc via TARGET_ASM_OUTPUT_DWARF_DTPREL.
    We need to emit DTP-relative relocations.  */
 
 static void
diff --git a/gcc/config/sparc/sparc.h b/gcc/config/sparc/sparc.h
index e8242d8..2e17fca 100644
--- a/gcc/config/sparc/sparc.h
+++ b/gcc/config/sparc/sparc.h
@@ -1322,7 +1322,7 @@ do {									\
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 
 #define REGNO_OK_FOR_INDEX_P(REGNO) \
@@ -1366,7 +1366,7 @@ do {									\
 
 /* Try a machine-dependent way of reloading an illegitimate address
    operand.  If we find one, push the reload and jump to WIN.  This
-   macro is used in only one place: `find_reloads_address' in reload.c.  */
+   macro is used in only one place: `find_reloads_address' in reload.cc.  */
 #define LEGITIMIZE_RELOAD_ADDRESS(X,MODE,OPNUM,TYPE,IND_LEVELS,WIN)	   \
 do {									   \
   int win;								   \
@@ -1513,7 +1513,7 @@ do {									   \
 /* On Sun 4, this limit is 2048.  We use 1000 to be safe, since the length
    can run past this up to a continuation point.  Once we used 1500, but
    a single entry in C++ can run more than 500 bytes, due to the length of
-   mangled symbol names.  dbxout.c should really be fixed to do
+   mangled symbol names.  dbxout.cc should really be fixed to do
    continuations when they are actually needed instead of trying to
    guess...  */
 #define DBX_CONTIN_LENGTH 1000
diff --git a/gcc/config/sparc/sparc.md b/gcc/config/sparc/sparc.md
index 62b7b53..691e707 100644
--- a/gcc/config/sparc/sparc.md
+++ b/gcc/config/sparc/sparc.md
@@ -1935,7 +1935,7 @@ visl")
   "or\t%1, %%lo(%a3-(%a2-.)), %0")
 
 ;; SPARC-v9 code model support insns.  See sparc_emit_set_symbolic_const64
-;; in sparc.c to see what is going on here... PIC stuff comes first.
+;; in sparc.cc to see what is going on here... PIC stuff comes first.
 
 (define_insn "movdi_lo_sum_pic"
   [(set (match_operand:DI 0 "register_operand" "=r")
@@ -2810,7 +2810,7 @@ visl")
 ;; it simple and only allow those constants supported by all flavors.
 ;; Note that emit_conditional_move canonicalizes operands 2,3 so that operand
 ;; 3 contains the constant if one is present, but we handle either for
-;; generality (sparc.c puts a constant in operand 2).
+;; generality (sparc.cc puts a constant in operand 2).
 ;;
 ;; Our instruction patterns, on the other hand, canonicalize such that
 ;; operand 3 must be the set destination.
diff --git a/gcc/config/sparc/t-sparc b/gcc/config/sparc/t-sparc
index 65b1313..2dd06c9 100644
--- a/gcc/config/sparc/t-sparc
+++ b/gcc/config/sparc/t-sparc
@@ -20,11 +20,11 @@
 
 PASSES_EXTRA += $(srcdir)/config/sparc/sparc-passes.def
 
-sparc-c.o: $(srcdir)/config/sparc/sparc-c.c
+sparc-c.o: $(srcdir)/config/sparc/sparc-c.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-sparc-d.o: $(srcdir)/config/sparc/sparc-d.c
+sparc-d.o: $(srcdir)/config/sparc/sparc-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/sparc/x-sparc b/gcc/config/sparc/x-sparc
index 5fc65be..a1b4ac3 100644
--- a/gcc/config/sparc/x-sparc
+++ b/gcc/config/sparc/x-sparc
@@ -1,4 +1,4 @@
-driver-sparc.o: $(srcdir)/config/sparc/driver-sparc.c
+driver-sparc.o: $(srcdir)/config/sparc/driver-sparc.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/stormy16/stormy16.cc b/gcc/config/stormy16/stormy16.cc
index f41c0dab..36fb97e 100644
--- a/gcc/config/stormy16/stormy16.cc
+++ b/gcc/config/stormy16/stormy16.cc
@@ -702,7 +702,7 @@ xstormy16_mode_dependent_address_p (const_rtx x,
       && ! LEGITIMATE_ADDRESS_INTEGER_P (XEXP (x, 1), 6))
     return true;
 
-  /* Auto-increment addresses are now treated generically in recog.c.  */
+  /* Auto-increment addresses are now treated generically in recog.cc.  */
   return false;
 }
 
diff --git a/gcc/config/t-darwin b/gcc/config/t-darwin
index ffdd09c..879539e 100644
--- a/gcc/config/t-darwin
+++ b/gcc/config/t-darwin
@@ -18,22 +18,22 @@
 
 TM_H += $(srcdir)/config/darwin-sections.def
 
-darwin.o: $(srcdir)/config/darwin.c config/darwin-sections.def
+darwin.o: $(srcdir)/config/darwin.cc config/darwin-sections.def
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-darwin-c.o: $(srcdir)/config/darwin-c.c
+darwin-c.o: $(srcdir)/config/darwin-c.cc
 	$(COMPILE) $(PREPROCESSOR_DEFINES) $<
 	$(POSTCOMPILE)
 
-darwin-d.o: $(srcdir)/config/darwin-d.c
+darwin-d.o: $(srcdir)/config/darwin-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-darwin-f.o: $(srcdir)/config/darwin-f.c
+darwin-f.o: $(srcdir)/config/darwin-f.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-darwin-driver.o: $(srcdir)/config/darwin-driver.c
+darwin-driver.o: $(srcdir)/config/darwin-driver.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/t-dragonfly b/gcc/config/t-dragonfly
index 0610f2d..a282579 100644
--- a/gcc/config/t-dragonfly
+++ b/gcc/config/t-dragonfly
@@ -16,6 +16,6 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-dragonfly-d.o: $(srcdir)/config/dragonfly-d.c
+dragonfly-d.o: $(srcdir)/config/dragonfly-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/t-freebsd b/gcc/config/t-freebsd
index 9f24c3b..37049f7 100644
--- a/gcc/config/t-freebsd
+++ b/gcc/config/t-freebsd
@@ -16,6 +16,6 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-freebsd-d.o: $(srcdir)/config/freebsd-d.c
+freebsd-d.o: $(srcdir)/config/freebsd-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/t-glibc b/gcc/config/t-glibc
index 5e3338a..c8b7d4e 100644
--- a/gcc/config/t-glibc
+++ b/gcc/config/t-glibc
@@ -16,10 +16,10 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-glibc-c.o: config/glibc-c.c
+glibc-c.o: config/glibc-c.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-glibc-d.o: config/glibc-d.c
+glibc-d.o: config/glibc-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/t-linux b/gcc/config/t-linux
index 58d9243..d9bc9b8 100644
--- a/gcc/config/t-linux
+++ b/gcc/config/t-linux
@@ -16,6 +16,6 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-linux.o: $(srcdir)/config/linux.c
+linux.o: $(srcdir)/config/linux.cc
 	  $(COMPILE) $<
 	  $(POSTCOMPILE)
diff --git a/gcc/config/t-netbsd b/gcc/config/t-netbsd
index 5fec4d6..77f850f 100644
--- a/gcc/config/t-netbsd
+++ b/gcc/config/t-netbsd
@@ -16,10 +16,10 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-netbsd.o: $(srcdir)/config/netbsd.c
+netbsd.o: $(srcdir)/config/netbsd.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-netbsd-d.o: $(srcdir)/config/netbsd-d.c
+netbsd-d.o: $(srcdir)/config/netbsd-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/t-openbsd b/gcc/config/t-openbsd
index 27a419d..69643f5 100644
--- a/gcc/config/t-openbsd
+++ b/gcc/config/t-openbsd
@@ -2,6 +2,6 @@
 USER_H = $(EXTRA_HEADERS)
 
 # OpenBSD-specific D support.
-openbsd-d.o: $(srcdir)/config/openbsd-d.c
+openbsd-d.o: $(srcdir)/config/openbsd-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/t-pnt16-warn b/gcc/config/t-pnt16-warn
index 5290578..1727a82 100644
--- a/gcc/config/t-pnt16-warn
+++ b/gcc/config/t-pnt16-warn
@@ -18,7 +18,7 @@
 # <http://www.gnu.org/licenses/>.
 
 
-# Because POINTER_SIZE is only 16, in dwarf2out.c,
+# Because POINTER_SIZE is only 16, in dwarf2out.cc,
 # DWARF_ARANGES_PAD_SIZE is 0, thus a loop in output_aranges that checks
 # (i < (unsigned) DWARF_ARANGES_PAD_SIZE) elicits a warning that the
 # comparison is always false.
diff --git a/gcc/config/t-sol2 b/gcc/config/t-sol2
index f0ee7d8..8732e2e 100644
--- a/gcc/config/t-sol2
+++ b/gcc/config/t-sol2
@@ -17,27 +17,27 @@
 # <http://www.gnu.org/licenses/>.
 
 # Solaris-specific format checking and pragmas.
-sol2-c.o: $(srcdir)/config/sol2-c.c
+sol2-c.o: $(srcdir)/config/sol2-c.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
 # Solaris-specific C++ mangling.
-sol2-cxx.o: $(srcdir)/config/sol2-cxx.c
+sol2-cxx.o: $(srcdir)/config/sol2-cxx.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
 # Solaris-specific D support.
-sol2-d.o: $(srcdir)/config/sol2-d.c
+sol2-d.o: $(srcdir)/config/sol2-d.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
 # Corresponding stub routines.
-sol2-stubs.o: $(srcdir)/config/sol2-stubs.c
+sol2-stubs.o: $(srcdir)/config/sol2-stubs.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
 # Solaris-specific attributes
-sol2.o: $(srcdir)/config/sol2.c
+sol2.o: $(srcdir)/config/sol2.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/t-vxworks b/gcc/config/t-vxworks
index cf90fcd..40c6cc4 100644
--- a/gcc/config/t-vxworks
+++ b/gcc/config/t-vxworks
@@ -16,11 +16,11 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-vxworks.o: $(srcdir)/config/vxworks.c
+vxworks.o: $(srcdir)/config/vxworks.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
-vxworks-c.o: $(srcdir)/config/vxworks-c.c
+vxworks-c.o: $(srcdir)/config/vxworks-c.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
diff --git a/gcc/config/t-winnt b/gcc/config/t-winnt
index 752bc53..c44e9bf 100644
--- a/gcc/config/t-winnt
+++ b/gcc/config/t-winnt
@@ -16,7 +16,7 @@
 # along with GCC; see the file COPYING3.  If not see
 # <http://www.gnu.org/licenses/>.
 
-winnt-c.o: config/winnt-c.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
+winnt-c.o: config/winnt-c.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(C_TARGET_H) $(C_TARGET_DEF_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) \
 	  $< $(OUTPUT_OPTION)
diff --git a/gcc/config/tilegx/t-tilegx b/gcc/config/tilegx/t-tilegx
index 20ee6d3..f357194 100644
--- a/gcc/config/tilegx/t-tilegx
+++ b/gcc/config/tilegx/t-tilegx
@@ -5,17 +5,17 @@ MULTILIB_OSDIRNAMES = ../lib ../lib32
 LIBGCC = stmp-multilib
 INSTALL_LIBGCC = install-multilib
 
-tilegx-c.o: $(srcdir)/config/tilegx/tilegx-c.c \
+tilegx-c.o: $(srcdir)/config/tilegx/tilegx-c.cc \
     $(CONFIG_H) $(SYSTEM_H) coretypes.h $(MACHMODE_H) \
     $(TM_H) $(TM_P_H) $(CPPLIB_H) $(TREE_H) $(C_COMMON_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
-$(srcdir)/config/tilegx/mul-tables.c: \
+$(srcdir)/config/tilegx/mul-tables.cc: \
     $(srcdir)/config/tilepro/gen-mul-tables.cc
 	$(CXX_FOR_BUILD) $(BUILD_CPPFLAGS) -O2 -o gen-mul-tables $<;
 	./gen-mul-tables > $@
 
-mul-tables.o: $(srcdir)/config/tilegx/mul-tables.c \
+mul-tables.o: $(srcdir)/config/tilegx/mul-tables.cc \
     $(CONFIG_H) $(SYSTEM_H) coretypes.h $(EXPR_H) $(OPTABS_H) \
     $(srcdir)/config/tilegx/tilegx-multiply.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/tilegx/tilegx-c.cc b/gcc/config/tilegx/tilegx-c.cc
index 627a5ac..6ef6808 100644
--- a/gcc/config/tilegx/tilegx-c.cc
+++ b/gcc/config/tilegx/tilegx-c.cc
@@ -26,7 +26,7 @@
 #include "tm.h"
 #include "c-family/c-common.h"
 
-/* copy defines in c-cppbuiltin.c */
+/* copy defines in c-cppbuiltin.cc */
 # define builtin_define(TXT) cpp_define (pfile, TXT)
 # define builtin_assert(TXT) cpp_assert (pfile, TXT)
 
diff --git a/gcc/config/tilegx/tilegx-protos.h b/gcc/config/tilegx/tilegx-protos.h
index 291d700..7263524 100644
--- a/gcc/config/tilegx/tilegx-protos.h
+++ b/gcc/config/tilegx/tilegx-protos.h
@@ -68,7 +68,7 @@ extern void tilegx_final_prescan_insn (rtx_insn *);
 extern const char *tilegx_asm_output_opcode (FILE *, const char *);
 extern void tilegx_function_profiler (FILE *, int);
 
-/* Declare functions in tilegx-c.c */
+/* Declare functions in tilegx-c.cc */
 
 extern void tilegx_cpu_cpp_builtins (struct cpp_reader *);
 
diff --git a/gcc/config/tilegx/tilegx.md b/gcc/config/tilegx/tilegx.md
index a98f4a7..7f89ae5 100644
--- a/gcc/config/tilegx/tilegx.md
+++ b/gcc/config/tilegx/tilegx.md
@@ -2421,7 +2421,7 @@
 
 
 ;;
-;; Divide stubs.  These exist to work around a bug in expmed.c, which
+;; Divide stubs.  These exist to work around a bug in expmed.cc, which
 ;; will not attempt to convert a divide by constant into a multiply
 ;; unless there is a pattern for a divide of the same mode.  The end
 ;; result is a 32-bit divide turns into 64-bit multiply.
diff --git a/gcc/config/tilepro/t-tilepro b/gcc/config/tilepro/t-tilepro
index 859331b..f64fd12 100644
--- a/gcc/config/tilepro/t-tilepro
+++ b/gcc/config/tilepro/t-tilepro
@@ -1,15 +1,15 @@
-tilepro-c.o: $(srcdir)/config/tilepro/tilepro-c.c \
+tilepro-c.o: $(srcdir)/config/tilepro/tilepro-c.cc \
     $(CONFIG_H) $(SYSTEM_H) coretypes.h $(MACHMODE_H) \
     $(TM_H) $(TM_P_H) $(CPPLIB_H) $(TREE_H) $(C_COMMON_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
 
-$(srcdir)/config/tilepro/mul-tables.c: \
+$(srcdir)/config/tilepro/mul-tables.cc: \
     $(srcdir)/config/tilepro/gen-mul-tables.cc
 	$(CXX_FOR_BUILD) $(BUILD_CPPFLAGS) -O2 -DTILEPRO \
 	  -o gen-mul-tables $<;
 	./gen-mul-tables > $@
 
-mul-tables.o: $(srcdir)/config/tilepro/mul-tables.c \
+mul-tables.o: $(srcdir)/config/tilepro/mul-tables.cc \
     $(CONFIG_H) $(SYSTEM_H) coretypes.h $(EXPR_H) $(OPTABS_H) \
     $(srcdir)/config/tilepro/tilepro-multiply.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $<
diff --git a/gcc/config/tilepro/tilepro-c.cc b/gcc/config/tilepro/tilepro-c.cc
index 14b08ea..ed91e710 100644
--- a/gcc/config/tilepro/tilepro-c.cc
+++ b/gcc/config/tilepro/tilepro-c.cc
@@ -26,7 +26,7 @@
 #include "tm.h"
 #include "c-family/c-common.h"
 
-/* copy defines in c-cppbuiltin.c */
+/* copy defines in c-cppbuiltin.cc */
 # define builtin_define(TXT) cpp_define (pfile, TXT)
 # define builtin_assert(TXT) cpp_assert (pfile, TXT)
 
diff --git a/gcc/config/v850/t-v850 b/gcc/config/v850/t-v850
index 27d9842..275ee8f 100644
--- a/gcc/config/v850/t-v850
+++ b/gcc/config/v850/t-v850
@@ -25,10 +25,10 @@ MULTILIB_DIRNAMES +=  v850e3v5
 
 TCFLAGS = -mno-app-regs -msmall-sld -Wa,-mwarn-signed-overflow -Wa,-mwarn-unsigned-overflow
 
-v850-c.o: $(srcdir)/config/v850/v850-c.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
+v850-c.o: $(srcdir)/config/v850/v850-c.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(TM_H) $(CPPLIB_H) $(TREE_H) $(C_PRAGMA_H) $(GGC_H) $(TM_P_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/v850/v850-c.c 
+		$(srcdir)/config/v850/v850-c.cc 
 
 # Local Variables:
 # mode: Makefile
diff --git a/gcc/config/v850/v850-protos.h b/gcc/config/v850/v850-protos.h
index e64c659..890552b 100644
--- a/gcc/config/v850/v850-protos.h
+++ b/gcc/config/v850/v850-protos.h
@@ -1,4 +1,4 @@
-/* Prototypes for v850.c functions used in the md file & elsewhere.
+/* Prototypes for v850.cc functions used in the md file & elsewhere.
    Copyright (C) 1999-2022 Free Software Foundation, Inc.
 
    This file is part of GCC.
diff --git a/gcc/config/v850/v850.cc b/gcc/config/v850/v850.cc
index bb282b0..c7d4329 100644
--- a/gcc/config/v850/v850.cc
+++ b/gcc/config/v850/v850.cc
@@ -1,4 +1,4 @@
-/* Subroutines for insn-output.c for NEC V850 series
+/* Subroutines for insn-output.cc for NEC V850 series
    Copyright (C) 1996-2022 Free Software Foundation, Inc.
    Contributed by Jeff Law (law@cygnus.com).
 
@@ -89,7 +89,7 @@ F (rtx x)
 /* Mark all the subexpressions of the PARALLEL rtx PAR as
    frame-related.  Return PAR.
 
-   dwarf2out.c:dwarf2out_frame_debug_expr ignores sub-expressions of a
+   dwarf2out.cc:dwarf2out_frame_debug_expr ignores sub-expressions of a
    PARALLEL rtx other than the first if they do not have the
    FRAME_RELATED flag set on them.  */
 
diff --git a/gcc/config/v850/v850.h b/gcc/config/v850/v850.h
index 544fbb3..328926e 100644
--- a/gcc/config/v850/v850.h
+++ b/gcc/config/v850/v850.h
@@ -351,7 +351,7 @@ enum reg_class
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
  
 #define REGNO_OK_FOR_BASE_P(regno)             \
@@ -569,7 +569,7 @@ struct cum_arg { int nbytes; };
    than accessing full words.  */
 #define SLOW_BYTE_ACCESS 1
 
-/* According expr.c, a value of around 6 should minimize code size, and
+/* According expr.cc, a value of around 6 should minimize code size, and
    for the V850 series, that's our primary concern.  */
 #define MOVE_RATIO(speed) 6
 
@@ -766,7 +766,7 @@ typedef enum
 /* enum GHS_SECTION_KIND is an enumeration of the kinds of sections that
    can appear in the "ghs section" pragma.  These names are used to index
    into the GHS_default_section_names[] and GHS_current_section_names[]
-   that are defined in v850.c, and so the ordering of each must remain
+   that are defined in v850.cc, and so the ordering of each must remain
    consistent. 
 
    These arrays give the default and current names for each kind of 
diff --git a/gcc/config/vax/vax.cc b/gcc/config/vax/vax.cc
index a5ad10d..20c4d52 100644
--- a/gcc/config/vax/vax.cc
+++ b/gcc/config/vax/vax.cc
@@ -1,4 +1,4 @@
-/* Subroutines for insn-output.c for VAX.
+/* Subroutines for insn-output.cc for VAX.
    Copyright (C) 1987-2022 Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -1948,7 +1948,7 @@ vax_mode_dependent_address_p (const_rtx x, addr_space_t as ATTRIBUTE_UNUSED)
 {
   rtx xfoo0, xfoo1;
 
-  /* Auto-increment cases are now dealt with generically in recog.c.  */
+  /* Auto-increment cases are now dealt with generically in recog.cc.  */
   if (GET_CODE (x) != PLUS)
     return false;
 
diff --git a/gcc/config/vax/vax.h b/gcc/config/vax/vax.h
index 0a5da67..45c0e75 100644
--- a/gcc/config/vax/vax.h
+++ b/gcc/config/vax/vax.h
@@ -359,7 +359,7 @@ enum reg_class { NO_REGS, ALL_REGS, LIM_REG_CLASSES };
    They give nonzero only if REGNO is a hard reg of the suitable class
    or a pseudo reg currently allocated to a suitable hard reg.
    Since they use reg_renumber, they are safe only once reg_renumber
-   has been allocated, which happens in reginfo.c during register
+   has been allocated, which happens in reginfo.cc during register
    allocation.  */
 
 #define REGNO_OK_FOR_INDEX_P(regno)	\
diff --git a/gcc/config/vax/vax.md b/gcc/config/vax/vax.md
index 5f2af49..2ce3620 100644
--- a/gcc/config/vax/vax.md
+++ b/gcc/config/vax/vax.md
@@ -1261,7 +1261,7 @@
 ;; The following used to be needed because constant propagation can
 ;; create them starting from the bic insn patterns above.  This is no
 ;; longer a problem.  However, having these patterns allows optimization
-;; opportunities in combine.c.
+;; opportunities in combine.cc.
 
 (define_insn_and_split "*and<mode>3_const_int"
   [(set (match_operand:VAXint 0 "nonimmediate_operand" "=g,g")
diff --git a/gcc/config/visium/visium.cc b/gcc/config/visium/visium.cc
index d7a460e..03c1a33 100644
--- a/gcc/config/visium/visium.cc
+++ b/gcc/config/visium/visium.cc
@@ -1850,7 +1850,7 @@ visium_legitimate_address_p (machine_mode mode, rtx x, bool strict)
 
 /* Try machine-dependent ways of modifying an illegitimate address
    to be legitimate.  If we find one, return the new, valid address.
-   This macro is used in only one place: `memory_address' in explow.c.
+   This macro is used in only one place: `memory_address' in explow.cc.
 
    OLDX is the address as it was before break_out_memory_refs was called.
    In some cases it is useful to look at this to decide what needs to be done.
diff --git a/gcc/config/visium/visium.h b/gcc/config/visium/visium.h
index d502e7d..e981924 100644
--- a/gcc/config/visium/visium.h
+++ b/gcc/config/visium/visium.h
@@ -376,7 +376,7 @@
    with spaces, and write first any length keyword, then `unsigned' if
    appropriate, and finally `int'.  The string must exactly match one
    of the data type names defined in the function
-   `init_decl_processing' in the file `c-decl.c'.  You may not omit
+   `init_decl_processing' in the file `c-decl.cc'.  You may not omit
    `int' or change the order--that would cause the compiler to crash
    on startup.
 
@@ -1234,7 +1234,7 @@ do									\
 
    `EXTRA_SECTION_FUNCTIONS'
 
-   One or more functions to be defined in `varasm.c'.  These functions
+   One or more functions to be defined in `varasm.cc'.  These functions
    should do jobs analogous to those of `text_section' and
    `data_section', for your additional sections.  Do not define this
    macro if you do not define `EXTRA_SECTIONS'.
@@ -1344,7 +1344,7 @@ do									\
    `IMMEDIATE_PREFIX'
 
    If defined, C string expressions to be used for the `%R', `%L',
-   `%U', and `%I' options of `asm_fprintf' (see `final.c').  These are
+   `%U', and `%I' options of `asm_fprintf' (see `final.cc').  These are
    useful when a single `md' file must support multiple assembler
    formats.  In that case, the various `tm.h' files can define these
    macros differently. */
diff --git a/gcc/config/vms/t-vms b/gcc/config/vms/t-vms
index 5cb9773..f099b48 100644
--- a/gcc/config/vms/t-vms
+++ b/gcc/config/vms/t-vms
@@ -23,18 +23,18 @@ vms-crtlmap.h: $(srcdir)/config/vms/vms-crtlmap.map  \
 	$(AWK) -f $(srcdir)/config/vms/make-crtlmap.awk \
 	  $(srcdir)/config/vms/vms-crtlmap.map > $@
 
-vms.o: $(srcdir)/config/vms/vms.c $(TREE_H) $(CONFIG_H) $(SYSTEM_H) \
+vms.o: $(srcdir)/config/vms/vms.cc $(TREE_H) $(CONFIG_H) $(SYSTEM_H) \
   coretypes.h $(TM_P_H) vms-crtlmap.h
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
 	  $< -o $@
 
-vms-c.o: $(srcdir)/config/vms/vms-c.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
+vms-c.o: $(srcdir)/config/vms/vms-c.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(TM_H) $(CPPLIB_H) $(TREE_H) c-family/c-pragma.h toplev.h $(GGC_H) \
   $(TM_P_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
           $(PREPROCESSOR_DEFINES) $< -o $@
 
-vms-f.o: $(srcdir)/config/vms/vms-f.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
+vms-f.o: $(srcdir)/config/vms/vms-f.cc $(CONFIG_H) $(SYSTEM_H) coretypes.h \
   $(TM_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
           $(PREPROCESSOR_DEFINES) $< -o $@
diff --git a/gcc/config/vms/vms-crtlmap.map b/gcc/config/vms/vms-crtlmap.map
index e80e2af..80331b2 100644
--- a/gcc/config/vms/vms-crtlmap.map
+++ b/gcc/config/vms/vms-crtlmap.map
@@ -12,7 +12,7 @@
 # - Comment lines start with '#' in the first column.
 # - map lines consist in an identifier optionnaly followed by at most 2
 #   space-separated flags.
-# Flags are described in vms.c (prefixed by VMS_CRTL_).
+# Flags are described in vms.cc (prefixed by VMS_CRTL_).
 #
 # Keep entries alpha-sorted - this is enforced by the awk script.
 #
diff --git a/gcc/config/vms/vms-protos.h b/gcc/config/vms/vms-protos.h
index 72607c4..b47aa83 100644
--- a/gcc/config/vms/vms-protos.h
+++ b/gcc/config/vms/vms-protos.h
@@ -17,13 +17,13 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-/* vms-c.c  */
+/* vms-c.cc  */
 extern void vms_c_register_pragma (void);
 extern void vms_c_common_override_options (void);
 extern int vms_c_get_crtl_ver (void);
 extern int vms_c_get_vms_ver (void);
 
-/* vms.c  */
+/* vms.cc  */
 void vms_patch_builtins (void);
 
 #ifdef TREE_CODE
diff --git a/gcc/config/vx-common.h b/gcc/config/vx-common.h
index 03f3316..aaae4f7 100644
--- a/gcc/config/vx-common.h
+++ b/gcc/config/vx-common.h
@@ -25,7 +25,7 @@ along with GCC; see the file COPYING3.  If not see
    to be used in port-specific vxworks.h.  */
 
 /* REAL_LIBGCC_SPEC needs to be used since the non-static option is not
-   handled in gcc.c.  */
+   handled in gcc.cc.  */
 #undef REAL_LIBGCC_SPEC
 #define REAL_LIBGCC_SPEC VXWORKS_LIBGCC_SPEC
 #undef STARTFILE_SPEC
diff --git a/gcc/config/x-darwin b/gcc/config/x-darwin
index c6226c0..8be4ce3 100644
--- a/gcc/config/x-darwin
+++ b/gcc/config/x-darwin
@@ -1,3 +1,3 @@
-host-darwin.o : $(srcdir)/config/host-darwin.c
+host-darwin.o : $(srcdir)/config/host-darwin.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/x-hpux b/gcc/config/x-hpux
index e9f2f18..86295f0 100644
--- a/gcc/config/x-hpux
+++ b/gcc/config/x-hpux
@@ -1,4 +1,4 @@
-host-hpux.o : $(srcdir)/config/host-hpux.c $(CONFIG_H) $(SYSTEM_H) \
+host-hpux.o : $(srcdir)/config/host-hpux.cc $(CONFIG_H) $(SYSTEM_H) \
   coretypes.h hosthooks.h hosthooks-def.h $(HOOKS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/host-hpux.c
+		$(srcdir)/config/host-hpux.cc
diff --git a/gcc/config/x-linux b/gcc/config/x-linux
index dba21a6..dd5b3a5 100644
--- a/gcc/config/x-linux
+++ b/gcc/config/x-linux
@@ -1,3 +1,3 @@
-host-linux.o : $(srcdir)/config/host-linux.c
+host-linux.o : $(srcdir)/config/host-linux.cc
 	  $(COMPILE) $<
 	  $(POSTCOMPILE)
diff --git a/gcc/config/x-netbsd b/gcc/config/x-netbsd
index beef745..c489bd7 100644
--- a/gcc/config/x-netbsd
+++ b/gcc/config/x-netbsd
@@ -1,4 +1,4 @@
-host-netbsd.o : $(srcdir)/config/host-netbsd.c $(CONFIG_H) $(SYSTEM_H) \
+host-netbsd.o : $(srcdir)/config/host-netbsd.cc $(CONFIG_H) $(SYSTEM_H) \
   coretypes.h hosthooks.h hosthooks-def.h $(HOOKS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/host-netbsd.c
+		$(srcdir)/config/host-netbsd.cc
diff --git a/gcc/config/x-openbsd b/gcc/config/x-openbsd
index 18e3f65..afec637 100644
--- a/gcc/config/x-openbsd
+++ b/gcc/config/x-openbsd
@@ -1,4 +1,4 @@
-host-openbsd.o : $(srcdir)/config/host-openbsd.c $(CONFIG_H) $(SYSTEM_H) \
+host-openbsd.o : $(srcdir)/config/host-openbsd.cc $(CONFIG_H) $(SYSTEM_H) \
   coretypes.h hosthooks.h hosthooks-def.h $(HOOKS_H)
 	$(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
-		$(srcdir)/config/host-openbsd.c
+		$(srcdir)/config/host-openbsd.cc
diff --git a/gcc/config/x-solaris b/gcc/config/x-solaris
index d50b4f5..c67b3e5 100644
--- a/gcc/config/x-solaris
+++ b/gcc/config/x-solaris
@@ -1,3 +1,3 @@
-host-solaris.o: $(srcdir)/config/host-solaris.c
+host-solaris.o: $(srcdir)/config/host-solaris.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
diff --git a/gcc/config/xtensa/xtensa-protos.h b/gcc/config/xtensa/xtensa-protos.h
index 357dba0..4bc42da 100644
--- a/gcc/config/xtensa/xtensa-protos.h
+++ b/gcc/config/xtensa/xtensa-protos.h
@@ -30,7 +30,7 @@ extern bool xtensa_b4constu (HOST_WIDE_INT);
 extern bool xtensa_mask_immediate (HOST_WIDE_INT);
 extern bool xtensa_mem_offset (unsigned, machine_mode);
 
-/* Functions within xtensa.c that we reference.  */
+/* Functions within xtensa.cc that we reference.  */
 #ifdef RTX_CODE
 extern int xt_true_regnum (rtx);
 extern int xtensa_valid_move (machine_mode, rtx *);
diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc
index e115b09..198bd3c 100644
--- a/gcc/config/xtensa/xtensa.cc
+++ b/gcc/config/xtensa/xtensa.cc
@@ -1,4 +1,4 @@
-/* Subroutines for insn-output.c for Tensilica's Xtensa architecture.
+/* Subroutines for insn-output.cc for Tensilica's Xtensa architecture.
    Copyright (C) 2001-2022 Free Software Foundation, Inc.
    Contributed by Bob Wilson (bwilson@tensilica.com) at Tensilica.
 
@@ -2243,7 +2243,7 @@ xtensa_option_override (void)
 
   /* Use CONST16 in the absence of L32R.
      Set it in the TARGET_OPTION_OVERRIDE to avoid dependency on xtensa
-     configuration in the xtensa-common.c  */
+     configuration in the xtensa-common.cc  */
 
   if (!TARGET_L32R)
     target_flags |= MASK_CONST16;
diff --git a/gcc/config/xtensa/xtensa.h b/gcc/config/xtensa/xtensa.h
index ea1fca2..00e2930 100644
--- a/gcc/config/xtensa/xtensa.h
+++ b/gcc/config/xtensa/xtensa.h
@@ -21,7 +21,7 @@ along with GCC; see the file COPYING3.  If not see
 /* Get Xtensa configuration settings */
 #include "xtensa-config.h"
 
-/* External variables defined in xtensa.c.  */
+/* External variables defined in xtensa.cc.  */
 
 /* Macros used in the machine description to select various Xtensa
    configuration options.  */