re PR middle-end/42509 (nonoverlapping_memrefs_p misinterprets NULL MEM_OFFSET as...

2010-04-03  Richard Guenther  <rguenther@suse.de>

	PR middle-end/42509
	* alias.c (nonoverlapping_memrefs_p): For spill-slot accesses
	require a non-NULL MEM_OFFSET.

From-SVN: r157954

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e06d38c..2eb77c4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2010-04-03  Richard Guenther  <rguenther@suse.de>
+
+       PR middle-end/42509
+       * alias.c (nonoverlapping_memrefs_p): For spill-slot accesses
+       require a non-NULL MEM_OFFSET.
+
 2010-04-02  Steven Bosscher  <steven@gcc.gnu.org>
 
        * ada/gcc-interface/Make-lang.in, alias.c, attribs.c, auto-inc-dec.c, 

diff --git a/gcc/alias.c b/gcc/alias.c
index 317aeba..cd7e2a0 100644 (file)
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -2147,6 +2147,13 @@ nonoverlapping_memrefs_p (const_rtx x, const_rtx y)
   if (exprx == 0 || expry == 0)
     return 0;
 
+  /* For spill-slot accesses make sure we have valid offsets.  */
+  if ((exprx == get_spill_slot_decl (false)
+       && ! MEM_OFFSET (x))
+      || (expry == get_spill_slot_decl (false)
+         && ! MEM_OFFSET (y)))
+    return 0;
+
   /* If both are field references, we may be able to determine something.  */
   if (TREE_CODE (exprx) == COMPONENT_REF
       && TREE_CODE (expry) == COMPONENT_REF