On Mon, 10 Nov 2025, Victor Do Nascimento wrote:
> Issues with alias list pruning for uncounted loops was found to cause
> as-of-yet unresolved issues in the execution of SpecV6. Disable this
> while a reduced testcase is developed and a solution implemented.
>
> Test derived from "omp_get_partition_place_nums" from libgomp "icv.c":
>
> unsigned len = 8;
>
> void
> alias_fail (int n[8])
> {
> unsigned int i;
> for (i = 0; i < len; i++)
> *n++ = i;
> }
>
> gcc/ChangeLog:
>
> * tree-vect-data-refs.cc (vect_prune_runtime_alias_test_list):
> Reject when !operand_equal_p for any data ref pair.
> ---
> gcc/tree-vect-data-refs.cc | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/tree-vect-data-refs.cc b/gcc/tree-vect-data-refs.cc
> index afdb44aedda..0c87973fc63 100644
> --- a/gcc/tree-vect-data-refs.cc
> +++ b/gcc/tree-vect-data-refs.cc
> @@ -4327,7 +4327,13 @@ vect_prune_runtime_alias_test_list (loop_vec_info
> loop_vinfo)
> {
> if (!operand_equal_p (DR_STEP (dr_info_a->dr),
> DR_STEP (dr_info_b->dr), 0))
> - length_factor = scalar_loop_iters;
> + {
> + length_factor = scalar_loop_iters;
move this
> + if (TREE_CODE (length_factor) == SCEV_NOT_KNOWN)
> + return opt_result::failure_at (vect_location,
> + "Unsupported alias check on"
> + " uncounted loop\n");
here. And use if (chrec_contains_undetermined (scalar_loop_iters)).
Diagnostics do not start with upper-case, so use "unsupported ...".
OK with that changes.
Richard.
> + }
> else
> length_factor = size_int (vect_factor);
> segment_length_a = vect_vfa_segment_size (dr_info_a, length_factor);
>
--
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
