> Am 28.12.2024 um 09:13 schrieb Jakub Jelinek <ja...@redhat.com>:
>
> Hi!
>
> The following testcases ICE because fold_array_ctor_reference in the
> RAW_DATA_CST handling just return build_int_cst without actually checking
> that if type is non-NULL, TREE_TYPE (val) is uselessly convertible to it.
>
> By falling through the code after it without *suboff += we get everything
> we need, the two if conditionals will never be true (we've already
> checked that size == BITS_PER_UNIT and so can't be 0, and val will be
> INTEGER_CST), but it will do the important fold_ctor_reference call
> which will deal with type incompatibilities.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok
Richard
> 2024-12-28 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/118207
> * gimple-fold.cc (fold_array_ctor_reference): For RAW_DATA_CST,
> just set val to build_int_cst and fall through to the normal
> element handling code instead of returning build_int_cst right away.
>
> * gcc.dg/pr118207.c: New test.
>
> --- gcc/gimple-fold.cc.jj 2024-12-19 10:21:11.162403694 +0100
> +++ gcc/gimple-fold.cc 2024-12-27 15:33:37.977988226 +0100
> @@ -9707,9 +9707,8 @@ fold_array_ctor_reference (tree type, tr
> constructor_elt *elt = CONSTRUCTOR_ELT (ctor, ctor_idx);
> if (elt->index == NULL_TREE || TREE_CODE (elt->index) != INTEGER_CST)
> return NULL_TREE;
> - *suboff += access_index.to_uhwi () * BITS_PER_UNIT;
> unsigned o = (access_index - wi::to_offset (elt->index)).to_uhwi ();
> - return build_int_cst (TREE_TYPE (val), RAW_DATA_UCHAR_ELT (val, o));
> + val = build_int_cst (TREE_TYPE (val), RAW_DATA_UCHAR_ELT (val, o));
> }
> if (!size && TREE_CODE (val) != CONSTRUCTOR)
> {
> --- gcc/testsuite/gcc.dg/pr118207.c.jj 2024-12-27 15:42:09.096826118 +0100
> +++ gcc/testsuite/gcc.dg/pr118207.c 2024-12-27 15:42:40.916379659 +0100
> @@ -0,0 +1,25 @@
> +/* PR tree-optimization/118207 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +struct A { unsigned char a; };
> +struct B { struct A b; };
> +static const unsigned char c[160] = {
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> + 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
> +struct B d;
> +
> +void
> +foo ()
> +{
> + const struct B *t = (const struct B *) &c;
> + d.b = t->b;
> +}
> --- gcc/testsuite/c-c++-common/cpp/embed-29.c.jj 2024-12-27
> 15:42:09.096826118 +0100
> +++ gcc/testsuite/c-c++-common/cpp/embed-29.c 2024-12-27
> 15:42:40.916379659 +0100
> @@ -0,0 +1,17 @@
> +/* PR tree-optimization/118207 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +struct A { unsigned char a; };
> +struct B { struct A b; };
> +static const unsigned char c[] = {
> +#embed __FILE__
> +};
> +struct B d;
> +
> +void
> +foo ()
> +{
> + const struct B *t = (const struct B *) &c;
> + d.b = t->b;
> +}
>
> Jakub
>
