(fill_simple_delay_slots): For the epilogue case, set needed

to include frame pointer and stack pointer, don't include all of
end_of_function_needs.	Reject insn if it sets a previously set
resource.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@8698 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 20 insertions, 1 deletions

diff --git a/gcc/reorg.c b/gcc/reorg.c
index cd7d6528f24..e4058d7e414 100644
--- a/gcc/reorg.c
+++ b/gcc/reorg.c
@@ -3146,9 +3146,27 @@ fill_simple_delay_slots (first, non_jumps_p)
     return;
 
   slots_filled = 0;
-  needed = end_of_function_needs;
   CLEAR_RESOURCE (&set);
 
+  /* The frame pointer and stack pointer are needed at the beginning of
+     the epilogue, so instructions setting them can not be put in the
+     epilogue delay slot.  However, everything else needed at function
+     end is safe, so we don't want to use end_of_function_needs here.  */
+  CLEAR_RESOURCE (&needed);
+  if (frame_pointer_needed)
+    {
+      SET_HARD_REG_BIT (needed.regs, FRAME_POINTER_REGNUM);
+#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
+      SET_HARD_REG_BIT (needed.regs, HARD_FRAME_POINTER_REGNUM);
+#endif
+#ifdef EXIT_IGNORE_STACK
+      if (! EXIT_IGNORE_STACK)
+#endif
+	SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM);
+    }
+  else
+    SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM);
+
   for (trial = get_last_insn (); ! stop_search_p (trial, 1);
        trial = PREV_INSN (trial))
     {
@@ -3160,6 +3178,7 @@ fill_simple_delay_slots (first, non_jumps_p)
 
       if (! insn_references_resource_p (trial, &set, 1)
 	  && ! insn_sets_resource_p (trial, &needed, 1)
+	  && ! insn_sets_resource_p (trial, &set, 1)
 #ifdef HAVE_cc0
 	  /* Don't want to mess with cc0 here.  */
 	  && ! reg_mentioned_p (cc0_rtx, pat)