* alias.c (get_alias_set): Call langhook before returning 0 for
types with structural equality.
* c-common.c (c_common_get_alias_set): Use alias set of element
type for arrays with structural comparison.
testsuite:
* gcc.dg/Wstrict-aliasing-bogus-vla-1.c: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@153496
138bc75d-0d04-0410-961f-
82ee72b054a4
+2009-10-23 Joseph Myers <joseph@codesourcery.com>
+
+ PR c/41673
+ * alias.c (get_alias_set): Call langhook before returning 0 for
+ types with structural equality.
+ * c-common.c (c_common_get_alias_set): Use alias set of element
+ type for arrays with structural comparison.
+
2009-10-23 Richard Guenther <rguenther@suse.de>
PR middle-end/41805
requires structural comparisons to identify compatible types
use alias set zero. */
if (TYPE_STRUCTURAL_EQUALITY_P (t))
- return 0;
+ {
+ /* Allow the language to specify another alias set for this
+ type. */
+ set = lang_hooks.get_alias_set (t);
+ if (set != -1)
+ return set;
+ return 0;
+ }
t = TYPE_CANONICAL (t);
/* Canonical types shouldn't form a tree nor should the canonical
type require structural equality checks. */
tree u;
PTR *slot;
+ /* For VLAs, use the alias set of the element type rather than the
+ default of alias set 0 for types compared structurally. */
+ if (TYPE_P (t) && TYPE_STRUCTURAL_EQUALITY_P (t))
+ {
+ if (TREE_CODE (t) == ARRAY_TYPE)
+ return get_alias_set (TREE_TYPE (t));
+ return -1;
+ }
+
/* Permit type-punning when accessing a union, provided the access
is directly through the union. For example, this code does not
permit taking the address of a union member and then storing
+2009-10-23 Joseph Myers <joseph@codesourcery.com>
+
+ PR c/41673
+ * gcc.dg/Wstrict-aliasing-bogus-vla-1.c: New test.
+
2009-10-23 Richard Guenther <rguenther@suse.de>
PR tree-optimization/41778
--- /dev/null
+/* PR 41673: bogus -Wstrict-aliasing warning from VLA dereference. */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -O2 -Wall" } */
+
+int main(int argc, char *argv[])
+{
+ float x[argc];
+ float y[argc];
+ return 0 == __builtin_memcpy(y, x, argc * sizeof(*x));
+}