* rtlanal.c (operand_preference): Fix preference for objects.

	* gcse.c (handle_avail_expr): Be prepared to handle single_set
	parallels.

	* combine.c (if_then_else_cond): Use simplify_subreg instead
	of operand_subword.
	* integreate.c (sub_constants): Likewise.

	* emit-rtl.c (constant_subword): Deprecate; remove most of code
	and use simplify_gen_subreg.

Mon Jun  4 19:55:23 CEST 2001  Lars Brinkhoff  <lars@nocrew.org>

	* sibcall.c (skip_copy_to_return_value): recognize the situation
	when the called function's return value is copied into an
	intermediate pseudo, and then into the calling functions return
	value register.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@42864 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 24 insertions, 0 deletions

diff --git a/gcc/sibcall.c b/gcc/sibcall.c
index 13f9c1f0069..53ce4317c96 100644
--- a/gcc/sibcall.c
+++ b/gcc/sibcall.c
@@ -169,6 +169,30 @@ skip_copy_to_return_value (orig_insn)
       && SET_SRC (set) == softret)
     return insn;
 
+  /* Recognize the situation when the called function's return value
+     is copied in two steps: first into an intermediate pseudo, then
+     the into the calling functions return value register.  */
+
+  if (REG_P (SET_DEST (set))
+      && SET_SRC (set) == softret)
+    {
+      rtx x = SET_DEST (set);
+
+      insn = next_nonnote_insn (insn);
+      if (! insn)
+	return orig_insn;
+
+      set = single_set (insn);
+      if (! set)
+	return orig_insn;
+
+      if (SET_DEST (set) == current_function_return_rtx
+	  && REG_P (SET_DEST (set))
+	  && OUTGOING_REGNO (REGNO (SET_DEST (set))) == REGNO (hardret)
+	  && SET_SRC (set) == x)
+	return insn;
+    }
+
   /* It did not look like a copy of the return value, so return the
      same insn we were passed.  */
   return orig_insn;