rtl.texi (simple_return): Document.

	* doc/rtl.texi (simple_return): Document.
	(parallel, PATTERN): Here too.
	* doc/md.texi (return): Mention it's allowed to expand to simple_return
	in some cases.
	(simple_return): Document standard pattern.
	* gengenrtl.c (special_rtx): SIMPLE_RETURN is special.
	* final.c (final_scan_insn): Use ANY_RETURN_P on body.
	* reorg.c (function_return_label, function_simple_return_label):
	New static variables, replacing...
	(end_of_function_label): ... this.
	(simplejump_or_return_p): New static function.
	(optimize_skip, steal_delay_list_from_fallthrough,
	fill_slots_from_thread): Use it.
	(relax_delay_slots): Likewise.  Use ANY_RETURN_P on body.
	(rare_destination, follow_jumps): Use ANY_RETURN_P on body.
	(find_end_label): Take a new arg which is one of the two return
	rtxs.  Depending on which, set either function_return_label or
	function_simple_return_label.  All callers changed.
	(make_return_insns): Make both kinds.
	(dbr_schedule): Adjust for two kinds of end labels.
	* function.c (emit_return_into_block): Set JUMP_LABEL properly.
	* genemit.c (gen_exp): Handle SIMPLE_RETURN.
	(gen_expand, gen_split): Use ANY_RETURN_P.
	* df-scan.c (df_uses_record): Handle SIMPLE_RETURN.
	* rtl.def (SIMPLE_RETURN): New code.
	* ifcvt.c (find_if_case_1): Be more careful about
	redirecting jumps to the EXIT_BLOCK.
	* jump.c (condjump_p, condjump_in_parallel_p, any_condjump_p,
	returnjump_p_1): Handle SIMPLE_RETURNs.
	* print-rtl.c (print_rtx): Likewise.
	* rtl.c (copy_rtx): Likewise.
	* bt-load.c (compute_defs_uses_and_gen): Use ANY_RETURN_P.
	* combine.c (simplify_set): Likewise.
	* resource.c (find_dead_or_set_registers, mark_set_resources):
	Likewise.
	* emit-rtl.c (verify_rtx_sharing, classify_insn, copy_insn_1,
	copy_rtx_if_shared_1, mark_used_flags): Handle SIMPLE_RETURNs.
	(init_emit_regs): Initialize simple_return_rtx.
	* cfglayout.c (fixup_reorder_chain): Pass a JUMP_LABEL to
	force_nonfallthru_and_redirect.
	* rtl.h (ANY_RETURN_P): Allow SIMPLE_RETURN.
	(GR_SIMPLE_RETURN): New enum value.
	(simple_return_rtx): New macro.
	* basic-block.h (force_nonfallthru_and_redirect): Adjust
	declaration.
	* cfgrtl.c (force_nonfallthru_and_redirect): Take a new jump_label
	argument.  All callers changed.  Be careful about what kinds of
	returnjumps to generate.
	* config/i386/3i86.c (ix86_pad_returns, ix86_count_insn_bb,
	ix86_pad_short_function): Likewise.
	* config/arm/arm.c (arm_final_prescan_insn): Handle both kinds
	of return.
	* config/mips/mips.md (any_return): New code_iterator.
	(optab): Add cases for return and simple_return.
	(return): Expand to a simple_return.
	(simple_return): New pattern.
	(*<optab>, *<optab>_internal for any_return): New patterns.
	(return_internal): Remove.
	* config/mips/mips.c (mips_expand_epilogue): Make the last insn
	a simple_return_internal.

From-SVN: r178135

1 files changed, 23 insertions, 7 deletions

diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index b60041a..b3f045b 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -1117,10 +1117,13 @@ rtl_redirect_edge_and_branch (edge e, basic_block target)
 }
 
 /* Like force_nonfallthru below, but additionally performs redirection
-   Used by redirect_edge_and_branch_force.  */
+   Used by redirect_edge_and_branch_force.  JUMP_LABEL is used only
+   when redirecting to the EXIT_BLOCK, it is either ret_rtx or
+   simple_return_rtx, indicating which kind of returnjump to create.
+   It should be NULL otherwise.  */
 
 basic_block
-force_nonfallthru_and_redirect (edge e, basic_block target)
+force_nonfallthru_and_redirect (edge e, basic_block target, rtx jump_label)
 {
   basic_block jump_block, new_bb = NULL, src = e->src;
   rtx note;
@@ -1252,12 +1255,25 @@ force_nonfallthru_and_redirect (edge e, basic_block target)
   e->flags &= ~EDGE_FALLTHRU;
   if (target == EXIT_BLOCK_PTR)
     {
+      if (jump_label == ret_rtx)
+	{
 #ifdef HAVE_return
-	emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc);
-	JUMP_LABEL (BB_END (jump_block)) = ret_rtx;
+	  emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc);
 #else
-	gcc_unreachable ();
+	  gcc_unreachable ();
 #endif
+	}
+      else
+	{
+	  gcc_assert (jump_label == simple_return_rtx);
+#ifdef HAVE_simple_return
+	  emit_jump_insn_after_setloc (gen_simple_return (),
+				       BB_END (jump_block), loc);
+#else
+	  gcc_unreachable ();
+#endif
+	}
+      JUMP_LABEL (BB_END (jump_block)) = jump_label;
     }
   else
     {
@@ -1284,7 +1300,7 @@ force_nonfallthru_and_redirect (edge e, basic_block target)
 static basic_block
 rtl_force_nonfallthru (edge e)
 {
-  return force_nonfallthru_and_redirect (e, e->dest);
+  return force_nonfallthru_and_redirect (e, e->dest, NULL_RTX);
 }
 
 /* Redirect edge even at the expense of creating new jump insn or
@@ -1301,7 +1317,7 @@ rtl_redirect_edge_and_branch_force (edge e, basic_block target)
   /* In case the edge redirection failed, try to force it to be non-fallthru
      and redirect newly created simplejump.  */
   df_set_bb_dirty (e->src);
-  return force_nonfallthru_and_redirect (e, target);
+  return force_nonfallthru_and_redirect (e, target, NULL_RTX);
 }
 
 /* The given edge should potentially be a fallthru edge.  If that is in