Jakub Jelinek <ja...@redhat.com> wrote:
>Hi!
>
>Before r200211 expand_expr_real_1 (and other places) used
>const_value_known_p which just returned a bool whether the DECL_INITIAL
>is usable, but now it has 3 possible return values, error_mark_node
>for unusable initial, NULL_TREE for no DECL_INITIAL, but const var
>(so, assuming zero initialization) and some other tree otherwise,
>while the new error_mark_node/NULL_TREE cases were both rejected
>previously. Because of that we can end up with NULL init now and
>crash on it.
>
>The following patch handles this case as zero initialization.
>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
Thanks,
Richard.
>2014-01-16 Jakub Jelinek <ja...@redhat.com>
>
> PR middle-end/58344
> * expr.c (expand_expr_real_1): Handle init == NULL_TREE.
>
> * gcc.c-torture/compile/pr58344.c: New test.
>
>--- gcc/expr.c.jj 2014-01-08 19:37:33.000000000 +0100
>+++ gcc/expr.c 2014-01-16 15:08:10.451913525 +0100
>@@ -9832,7 +9832,25 @@ expand_expr_real_1 (tree exp, rtx target
> || TREE_CODE (array) == CONST_DECL)
> && (init = ctor_for_folding (array)) != error_mark_node)
> {
>- if (TREE_CODE (init) == CONSTRUCTOR)
>+ if (init == NULL_TREE)
>+ {
>+ tree value = build_zero_cst (type);
>+ if (TREE_CODE (value) == CONSTRUCTOR)
>+ {
>+ /* If VALUE is a CONSTRUCTOR, this optimization is only
>+ useful if this doesn't store the CONSTRUCTOR into
>+ memory. If it does, it is more efficient to just
>+ load the data from the array directly. */
>+ rtx ret = expand_constructor (value, target,
>+ modifier, true);
>+ if (ret == NULL_RTX)
>+ value = NULL_TREE;
>+ }
>+
>+ if (value)
>+ return expand_expr (value, target, tmode, modifier);
>+ }
>+ else if (TREE_CODE (init) == CONSTRUCTOR)
> {
> unsigned HOST_WIDE_INT ix;
> tree field, value;
>--- gcc/testsuite/gcc.c-torture/compile/pr58344.c.jj 2014-01-16
>15:13:45.875197932 +0100
>+++ gcc/testsuite/gcc.c-torture/compile/pr58344.c 2014-01-16
>15:13:07.000000000 +0100
>@@ -0,0 +1,12 @@
>+/* PR middle-end/58344 */
>+/* { dg-do compile } */
>+
>+struct U {};
>+static struct U a[1];
>+extern void bar (struct U);
>+
>+void
>+foo (void)
>+{
>+ bar (a[0]);
>+}
>
> Jakub
