[PATCH] Fold &a < &a + 4 with -fno-strict-overflow

[Richard Guenther]

I noticed we do not optimize any of the vectorizer alias tests
with -fno-strict-overflow.  The following fixes this.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.

Richard.

2011-08-24  Richard Guenther  <rguent...@suse.de>

        * fold-const.c (fold_comparison): Fold &a < &a + 4 even
        with -fno-strict-overflow.

Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c    (revision 178031)
+++ gcc/fold-const.c    (working copy)
@@ -8738,6 +8738,7 @@ fold_comparison (location_t loc, enum tr
                   && operand_equal_p (offset0, offset1, 0)))
              && (code == EQ_EXPR
                  || code == NE_EXPR
+                 || (indirect_base0 && DECL_P (base0))
                  || POINTER_TYPE_OVERFLOW_UNDEFINED))
 
            {
@@ -8777,6 +8778,7 @@ fold_comparison (location_t loc, enum tr
             6.5.6/8 and /9 with respect to the signed ptrdiff_t.  */
          else if (bitpos0 == bitpos1
                   && ((code == EQ_EXPR || code == NE_EXPR)
+                      || (indirect_base0 && DECL_P (base0))
                       || POINTER_TYPE_OVERFLOW_UNDEFINED))
            {
              /* By converting to signed size type we cover middle-end pointer