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.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@83901 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 28 insertions, 9 deletions

diff --git a/gcc/reorg.c b/gcc/reorg.c
index 9b3c9fd6f2f..da4a1a03e83 100644
--- a/gcc/reorg.c
+++ b/gcc/reorg.c
@@ -317,6 +317,20 @@ insn_sets_resource_p (rtx insn, struct resources *res,
   mark_set_resources (insn, &insn_sets, 0, include_delayed_effects);
   return resource_conflicts_p (&insn_sets, res);
 }
+
+/* Return TRUE if INSN is a return, possibly with a filled delay slot.  */
+
+static bool
+return_insn_p (rtx insn)
+{
+  if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == RETURN)
+    return true;
+
+  if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == SEQUENCE)
+    return return_insn_p (XVECEXP (PATTERN (insn), 0, 0));
+
+  return false;
+}
 
 /* Find a label at the end of the function or before a RETURN.  If there is
    none, make one.  */
@@ -344,15 +358,13 @@ find_end_label (void)
   /* When a target threads its epilogue we might already have a
      suitable return insn.  If so put a label before it for the
      end_of_function_label.  */
-  if (GET_CODE (insn) == BARRIER
-      && GET_CODE (PREV_INSN (insn)) == JUMP_INSN
-      && GET_CODE (PATTERN (PREV_INSN (insn))) == RETURN)
+  if (GET_CODE (insn) == BARRIER && return_insn_p (PREV_INSN (insn)))
     {
       rtx temp = PREV_INSN (PREV_INSN (insn));
       end_of_function_label = gen_label_rtx ();
       LABEL_NUSES (end_of_function_label) = 0;
 
-      /* Put the label before an USE insns that may proceed the RETURN insn.  */
+      /* Put the label before an USE insn that may precede the RETURN insn.  */
       while (GET_CODE (temp) == USE)
 	temp = PREV_INSN (temp);
 
@@ -368,8 +380,7 @@ find_end_label (void)
       /* If the basic block reorder pass moves the return insn to
 	 some other place try to locate it again and put our
 	 end_of_function_label there.  */
-      while (insn && ! (GET_CODE (insn) == JUMP_INSN
-		        && (GET_CODE (PATTERN (insn)) == RETURN)))
+      while (insn && ! return_insn_p (insn))
 	insn = PREV_INSN (insn);
       if (insn)
 	{
@@ -3275,10 +3286,18 @@ relax_delay_slots (rtx first)
 	    {
 	      target_label = JUMP_LABEL (XVECEXP (PATTERN (trial), 0, 0));
 	      if (target_label == 0)
-		target_label = find_end_label ();
+		{
+		  target_label = find_end_label ();
+		  /* The following condition may be true if TRIAL contains
+		     the unique RETURN.  In this case, threading would be
+		     a nop and we would enter an infinite loop if we did it.  */
+		  if (next_active_insn (target_label) == trial)
+		    target_label = 0;
+		}
 
-	      if (redirect_with_delay_slots_safe_p (delay_insn, target_label,
-						    insn))
+	      if (target_label
+		  && redirect_with_delay_slots_safe_p (delay_insn, target_label,
+						       insn))
 		{
 		  reorg_redirect_jump (delay_insn, target_label);
 		  next = insn;