diff options
| -rw-r--r-- | gcc/config/nvptx/nvptx.cc | 188 | ||||
| -rw-r--r-- | gcc/config/nvptx/nvptx.opt | 4 |
2 files changed, 192 insertions, 0 deletions
diff --git a/gcc/config/nvptx/nvptx.cc b/gcc/config/nvptx/nvptx.cc index ed347ca..a37a6c7 100644 --- a/gcc/config/nvptx/nvptx.cc +++ b/gcc/config/nvptx/nvptx.cc @@ -5372,6 +5372,190 @@ workaround_barsyncs (void) } #endif +/* Initialize all declared regs at function entry. + Advantage : Fool-proof. + Disadvantage: Potentially creates a lot of long live ranges and adds a lot + of insns. */ + +static void +workaround_uninit_method_1 (void) +{ + rtx_insn *first = get_insns (); + rtx_insn *insert_here = NULL; + + for (int ix = LAST_VIRTUAL_REGISTER + 1; ix < max_reg_num (); ix++) + { + rtx reg = regno_reg_rtx[ix]; + + /* Skip undeclared registers. */ + if (reg == const0_rtx) + continue; + + gcc_assert (CONST0_RTX (GET_MODE (reg))); + + start_sequence (); + emit_move_insn (reg, CONST0_RTX (GET_MODE (reg))); + rtx_insn *inits = get_insns (); + end_sequence (); + + if (dump_file && (dump_flags & TDF_DETAILS)) + for (rtx_insn *init = inits; init != NULL; init = NEXT_INSN (init)) + fprintf (dump_file, "Default init of reg %u inserted: insn %u\n", + ix, INSN_UID (init)); + + if (first != NULL) + { + insert_here = emit_insn_before (inits, first); + first = NULL; + } + else + insert_here = emit_insn_after (inits, insert_here); + } +} + +/* Find uses of regs that are not defined on all incoming paths, and insert a + corresponding def at function entry. + Advantage : Simple. + Disadvantage: Potentially creates long live ranges. + May not catch all cases. F.i. a clobber cuts a live range in + the compiler and may prevent entry_lr_in from being set for a + reg, but the clobber does not translate to a ptx insn, so in + ptx there still may be an uninitialized ptx reg. See f.i. + gcc.c-torture/compile/20020926-1.c. */ + +static void +workaround_uninit_method_2 (void) +{ + auto_bitmap entry_pseudo_uninit; + { + auto_bitmap not_pseudo; + bitmap_set_range (not_pseudo, 0, LAST_VIRTUAL_REGISTER); + + bitmap entry_lr_in = DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun)); + bitmap_and_compl (entry_pseudo_uninit, entry_lr_in, not_pseudo); + } + + rtx_insn *first = get_insns (); + rtx_insn *insert_here = NULL; + + bitmap_iterator iterator; + unsigned ix; + EXECUTE_IF_SET_IN_BITMAP (entry_pseudo_uninit, 0, ix, iterator) + { + rtx reg = regno_reg_rtx[ix]; + gcc_assert (CONST0_RTX (GET_MODE (reg))); + + start_sequence (); + emit_move_insn (reg, CONST0_RTX (GET_MODE (reg))); + rtx_insn *inits = get_insns (); + end_sequence (); + + if (dump_file && (dump_flags & TDF_DETAILS)) + for (rtx_insn *init = inits; init != NULL; init = NEXT_INSN (init)) + fprintf (dump_file, "Missing init of reg %u inserted: insn %u\n", + ix, INSN_UID (init)); + + if (first != NULL) + { + insert_here = emit_insn_before (inits, first); + first = NULL; + } + else + insert_here = emit_insn_after (inits, insert_here); + } +} + +/* Find uses of regs that are not defined on all incoming paths, and insert a + corresponding def on those. + Advantage : Doesn't create long live ranges. + Disadvantage: More complex, and potentially also more defs. */ + +static void +workaround_uninit_method_3 (void) +{ + auto_bitmap not_pseudo; + bitmap_set_range (not_pseudo, 0, LAST_VIRTUAL_REGISTER); + + basic_block bb; + FOR_EACH_BB_FN (bb, cfun) + { + if (single_pred_p (bb)) + continue; + + auto_bitmap bb_pseudo_uninit; + bitmap_and_compl (bb_pseudo_uninit, DF_LIVE_IN (bb), DF_MIR_IN (bb)); + bitmap_and_compl_into (bb_pseudo_uninit, not_pseudo); + + bitmap_iterator iterator; + unsigned ix; + EXECUTE_IF_SET_IN_BITMAP (bb_pseudo_uninit, 0, ix, iterator) + { + bool have_false = false; + bool have_true = false; + + edge e; + edge_iterator ei; + FOR_EACH_EDGE (e, ei, bb->preds) + { + if (bitmap_bit_p (DF_LIVE_OUT (e->src), ix)) + have_true = true; + else + have_false = true; + } + if (have_false ^ have_true) + continue; + + FOR_EACH_EDGE (e, ei, bb->preds) + { + if (bitmap_bit_p (DF_LIVE_OUT (e->src), ix)) + continue; + + rtx reg = regno_reg_rtx[ix]; + gcc_assert (CONST0_RTX (GET_MODE (reg))); + + start_sequence (); + emit_move_insn (reg, CONST0_RTX (GET_MODE (reg))); + rtx_insn *inits = get_insns (); + end_sequence (); + + if (dump_file && (dump_flags & TDF_DETAILS)) + for (rtx_insn *init = inits; init != NULL; + init = NEXT_INSN (init)) + fprintf (dump_file, + "Missing init of reg %u inserted on edge: %d -> %d:" + " insn %u\n", ix, e->src->index, e->dest->index, + INSN_UID (init)); + + insert_insn_on_edge (inits, e); + } + } + } + + commit_edge_insertions (); +} + +static void +workaround_uninit (void) +{ + switch (nvptx_init_regs) + { + case 0: + /* Skip. */ + break; + case 1: + workaround_uninit_method_1 (); + break; + case 2: + workaround_uninit_method_2 (); + break; + case 3: + workaround_uninit_method_3 (); + break; + default: + gcc_unreachable (); + } +} + /* PTX-specific reorganization - Split blocks at fork and join instructions - Compute live registers @@ -5401,6 +5585,8 @@ nvptx_reorg (void) df_set_flags (DF_NO_INSN_RESCAN | DF_NO_HARD_REGS); df_live_add_problem (); df_live_set_all_dirty (); + if (nvptx_init_regs == 3) + df_mir_add_problem (); df_analyze (); regstat_init_n_sets_and_refs (); @@ -5413,6 +5599,8 @@ nvptx_reorg (void) if (REG_N_SETS (i) == 0 && REG_N_REFS (i) == 0) regno_reg_rtx[i] = const0_rtx; + workaround_uninit (); + /* Determine launch dimensions of the function. If it is not an offloaded function (i.e. this is a regular compiler), the function has no neutering. */ diff --git a/gcc/config/nvptx/nvptx.opt b/gcc/config/nvptx/nvptx.opt index e3f65b2..0858007 100644 --- a/gcc/config/nvptx/nvptx.opt +++ b/gcc/config/nvptx/nvptx.opt @@ -91,3 +91,7 @@ Enum(ptx_version) String(7.0) Value(PTX_VERSION_7_0) mptx= Target RejectNegative ToLower Joined Enum(ptx_version) Var(ptx_version_option) Specify the version of the ptx version to use. + +minit-regs= +Target Var(nvptx_init_regs) IntegerRange(0, 3) Joined UInteger Init(3) +Initialize ptx registers. |