------- Comment #20 from rguenth at gcc dot gnu dot org 2010-04-02 12:09
-------
The obvious bug is that nonoverlapping_memrefs_p thinks that a NULL
MEM_OFFSET is equal to MEM_OFFSET == const0_rtx. It is not, it's
"unknown offset".
The following should fix that.
Index: gcc/alias.c
===================================================================
--- gcc/alias.c (revision 157942)
+++ gcc/alias.c (working copy)
@@ -2268,6 +2268,10 @@ nonoverlapping_memrefs_p (const_rtx x, c
: MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) :
-1);
+ /* If the offset is unknown we cannot determine anything. */
+ if (!moffsetx || !moffsety)
+ return 0;
+
/* If we have an offset for either memref, it can update the values computed
above. */
if (moffsetx)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42509
