Index: alias.c
===================================================================
--- alias.c	(revision 193992)
+++ alias.c	(working copy)
@@ -2103,6 +2103,10 @@
      alignment into account.  */
   if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1)))
     {
+      if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1)))
+	xsize = -1;
+      return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c);
+#if 0
       HOST_WIDE_INT sc = INTVAL (XEXP (x, 1));
       unsigned HOST_WIDE_INT uc = sc;
       if (xsize > 0 && sc < 0 && -uc == (uc & -uc))
@@ -2112,9 +2116,14 @@
 	  return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
 				     ysize, y, c);
 	}
+#endif
     }
   if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1)))
     {
+      if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1)))
+	ysize = -1;
+      return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c);
+#if 0
       HOST_WIDE_INT sc = INTVAL (XEXP (y, 1));
       unsigned HOST_WIDE_INT uc = sc;
       if (ysize > 0 && sc < 0 && -uc == (uc & -uc))
@@ -2124,6 +2133,7 @@
 	  return memrefs_conflict_p (xsize, x,
 				     ysize, canon_rtx (XEXP (y, 0)), c);
 	}
+#endif
     }
 
   if (CONSTANT_P (x))