===================================================================
@@ -0,0 +1,11 @@
+int
+main (int argc, char **argv)
+{
+ int c;
+ unsigned char out[][1] = { {71}, {71}, {71} };
+
+ for (int i = 0; i < 3; i++)
+ if (!out[i][0])
+ __builtin_abort ();
+ return 0;
+}
===================================================================
@@ -12,4 +12,4 @@ test(int i,int j)
(*innerptr)[3][j]=11;
return (*barptr)[i][2][j];
}
-/* { dg-final { scan-tree-dump-times "return 10" 1 "fre3"} } */
+/* { dg-final { scan-tree-dump-times "return 10" 1 "fre3" { xfail *-*-* } } } */
===================================================================
@@ -1444,20 +1444,36 @@ nonoverlapping_refs_since_match_p (tree
for (; narray_refs1 > narray_refs2; narray_refs1--)
{
ref1 = component_refs1.pop ();
- /* Track whether we possibly introduced partial overlap assuming
- that innermost type sizes does not match. This only can
- happen if the offset introduced by the ARRAY_REF
- is non-zero. */
+
+ /* If index is non-zero we need to check whether the reference
+ does not break the main invariant that bases are either
+ disjoint or equal. Consider the example:
+
+ unsigned char out[][1];
+ out[1]="a";
+ out[i][0];
+
+ Here bases out and out are same, but after removing the
+ [i] index, this invariant no longer holds, because
+ out[i] points to the middle of array out.
+
+ TODO: If size of type of the skipped reference is an integer
+ multiply of the size of type of the other reference this
+ invariant can be verified, but even then it is not completely
+ safe with !flag_strict_aliasing if the other reference contains
+ unbounded array accesses.
+ See */
+
if (!operand_equal_p (TREE_OPERAND (ref1, 1),
cheap_array_ref_low_bound (ref1), 0))
- seen_unmatched_ref_p = true;
+ return 0;
}
for (; narray_refs2 > narray_refs1; narray_refs2--)
{
ref2 = component_refs2.pop ();
if (!operand_equal_p (TREE_OPERAND (ref2, 1),
cheap_array_ref_low_bound (ref2), 0))
- seen_unmatched_ref_p = true;
+ return 0;
}
/* Try to disambiguate matched arrays. */
for (unsigned int i = 0; i < narray_refs1; i++)