RTL prologue/epilogue for SPARC

	RTL prologue/epilogue for SPARC
	* config/sparc/sparc-protos.h (sparc_emitting_epilogue): Delete.
	(sparc_skip_caller_unimp): Likewise.
	(load_pic_register): Likewise.
	(leaf_return_peephole_ok): Likewise.
	(compute_frame_size): Rename into sparc_compute_frame_size.
	(sparc_expand_prologue): New prototype.
	(sparc_expand_epilogue): Likewise.
	(output_return): Likewise.
	(eligible_for_epilogue_delay): Rename into eligible_for_return_delay.
	* config/sparc/sparc.h (INITIAL_ELIMINATION_OFFSET): Adjust call to
	compute_frame_size.  Move comment up.
	(DELAY_SLOTS_FOR_EPILOGUE): Delete.
	(ELIGIBLE_FOR_EPILOGUE_DELAY): Likewise.
	(EPILOGUE_USES): Return true for %g1 if the function uses EH return.
	* config/sparc/sparc.md (UNSPECV_SAVEW): New constant.
	(type attribute): Add 'return' and 'savew'.
	(eligible_for_return_delay): New attribute.
	(return): New delay_slot.
	(sibcall_epilogue): Call sparc_expand_epilogue.
	(prologue): Likewise.  Move up.
	(save_register_window): New expander.
	(save_register_windowsi): New pattern.
	(save_register_windowdi): Likewise.
	(epilogue): New expander.
	(return_internal): New pattern.
	(Return peepholes): Delete.
	* config/sparc/sparc.c (SIBCALL_SLOT_EMPTY_P): New macro.
	(sparc_emitting_epilogue): Delete.
	(sparc_skip_caller_unimp): Likewise.
	(sparc_sr_alias_set): New global variable.
	(frame_base_name): Delete.
	(frame_base_reg): New global variable.
	(sparc_override_options): Get new alias set for save/restore.
	(leaf_return_peephole_ok): Delete.
	(eligible_for_epilogue_delay): Rename into eligible_for_return_delay.
	Factor out code into eligible_for_restore_insn_delay.
	(eligible_for_restore_insn_delay): New function extraced from above.
	Use IN_UNCOND_BRANCH_DELAY_TRUE instead of IN_BRANCH_DELAY_TRUE.
	(eligible_for_sibcall_delay): Use SIBCALL_SLOT_EMPTY_P.
	Factor out code into eligible_for_restore_insn_delay.
	(load_pic_register): Make static.  Remove check.
	(save_regs): Delete.
	(restore_regs): Likewise.
	(compute_frame_size): Rename into sparc_compute_frame_size.
	Rename leaf_function into leaf_function_p.
	(build_big_number): Delete.
	(save_or_restore_regs): New function.
	(emit_save_regs): Likewise.
	(emit_restore_regs): Likewise.
	(emit_stack_pointer_increment ): Likewise.
	(emit_stack_pointer_decrement): Likewise.
	(sparc_expand_prologue): Likewise.
	(sparc_function_prologue): Rename into sparc_asm_function_prologue.
	Remove all code to emit instructions.
	(sparc_expand_epilogue): New function.
	(sparc_function_epilogue): Rename into sparc_asm_function_epilogue.
	Remove all code to emit instructions.
	(output_restore): New function.
	(output_return): Likewise.
	(output_sibcall): Factor out code into output_restore.
	(print_operand): Adjust for frame_base_reg.
	* target.h (struct gcc_target): New field 'late_rtl_prologue_epilogue'.
	* target-def.h (TARGET_LATE_RTL_PROLOGUE_EPILOGUE): New define.
	(TARGET_INITIALIZER): Add it.
	* passes.c (rest_of_compilation): Set the conditional predicate
	'current_function_uses_only_leaf_regs' before sched2.  If target
	has 'late_rtl_prologue_epilogue', emit RTL prologue/epilogue right
	before sched2.
	* reorg.c (return_insn_p): New predicate.
	(find_end_label): Use it.
	(relax_delay_slots): Do not thread an unconditional jump that points
	to the end return label.
	* doc/tm.texi (Registers) <Leaf Functions>: Clarify the validity
	domain of 'current_function_uses_only_leaf_regs'.
	(Stack and Calling) <Function Entry>: Document new target hook
	TARGET_LATE_RTL_PROLOGUE_EPILOGUE.

From-SVN: r83901

1 files changed, 13 insertions, 8 deletions

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 944477d..5f32581 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -2218,8 +2218,9 @@ set prior to local register allocation and is valid for the remaining
 compiler passes.  They can also test the C variable
 @code{current_function_uses_only_leaf_regs} which is nonzero for leaf
 functions which only use leaf registers.
-@code{current_function_uses_only_leaf_regs} is valid after reload and is
-only useful if @code{LEAF_REGISTERS} is defined.
+@code{current_function_uses_only_leaf_regs} is valid after all passes
+that modify the instructions have been run and is only useful if
+@code{LEAF_REGISTERS} is defined.
 @c changed this to fix overfull.  ALSO:  why the "it" at the beginning
 @c of the next paragraph?!  --mew 2feb93
 
@@ -4211,6 +4212,16 @@ arguments that a function should pop.  @xref{Scalar Return}.
 @c tell?  --mew 5feb93
 @end deftypefn
 
+@deftypefn {Target Hook} bool TARGET_LATE_RTL_PROLOGUE_EPILOGUE
+If set to @code{true}, it instructs the compiler to emit the RTL prologue
+and epilogue later in the game than usual, namely after all passes that
+modify the instructions (and not merely reorder them) have been run.  In
+particular, the C variable @code{current_function_uses_only_leaf_regs} is
+valid at that point.  This can be used on machines that have "register
+windows" to optimize away the regular "push" on the register stack.
+@xref{Leaf Functions}.
+@end deftypefn
+
 @itemize @bullet
 @item
 @findex current_function_pretend_args_size
@@ -4245,12 +4256,6 @@ Optionally, when @code{ACCUMULATE_OUTGOING_ARGS} is defined, a region of
 argument lists of the function.  @xref{Stack Arguments}.
 @end itemize
 
-Normally, it is necessary for the macros
-@code{TARGET_ASM_FUNCTION_PROLOGUE} and
-@code{TARGET_ASM_FUNCTION_EPILOGUE} to treat leaf functions specially.
-The C variable @code{current_function_is_leaf} is nonzero for such a
-function.
-
 @defmac EXIT_IGNORE_STACK
 Define this macro as a C expression that is nonzero if the return
 instruction or the function epilogue ignores the value of the stack