On Mon, Aug 07, 2017 at 10:47:51AM +0200, Marek Polacek wrote:
> In my recent change I failed to check whether the type domain
> of a type is non-NULL and this goof causes crashing on this
> testcase.
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk?
>
> 2017-08-07 Marek Polacek <pola...@redhat.com>
>
> PR middle-end/81737
> * fold-const.c (fold_indirect_ref_1): Check type_domain.
>
> * gcc.dg/pr81737.c: New test.
The old code was assuming size_zero_node if type_domain is NULL
or TYPE_MIN_VALUE is NULL, which is reasonable for C/C++, but indeed might
be wrong perhaps for Fortran or Ada.
Hopefully nothing will assume this has to be folded in these cases (mainly
thinking about C++ constexpr).
So ok.
> diff --git gcc/fold-const.c gcc/fold-const.c
> index d563ba76766..8eaea6cce3a 100644
> --- gcc/fold-const.c
> +++ gcc/fold-const.c
> @@ -14107,8 +14107,10 @@ fold_indirect_ref_1 (location_t loc, tree type, tree
> op0)
> && type == TREE_TYPE (op00type))
> {
> tree type_domain = TYPE_DOMAIN (op00type);
> - tree min = TYPE_MIN_VALUE (type_domain);
> - if (min && TREE_CODE (min) == INTEGER_CST)
> + tree min;
> + if (type_domain != NULL_TREE
> + && (min = TYPE_MIN_VALUE (type_domain))
> + && TREE_CODE (min) == INTEGER_CST)
> {
> offset_int off = wi::to_offset (op01);
> offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type));
> diff --git gcc/testsuite/gcc.dg/pr81737.c gcc/testsuite/gcc.dg/pr81737.c
> index e69de29bb2d..493358956ef 100644
> --- gcc/testsuite/gcc.dg/pr81737.c
> +++ gcc/testsuite/gcc.dg/pr81737.c
> @@ -0,0 +1,6 @@
> +/* PR middle-end/81737 */
> +/* { dg-do compile } */
> +/* { dg-options "" } */
> +
> +extern int a[];
> +void fn1() { (a + 0)[1]; }
>
> Marek
Jakub
