[Bug tree-optimization/118558] [15 Regression] csmith: another runtime error with march=znver3 since r15-3467-g5df05de3d91775

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118558

--- Comment #10 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:7fffff1deb47a70ff804f0b2cce7be7e5fe8ba13

commit r15-7149-g7fffff1deb47a70ff804f0b2cce7be7e5fe8ba13
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Jan 21 14:58:43 2025 +0100

    tree-optimization/118558 - fix alignment compute with
VMAT_CONTIGUOUS_REVERSE

    There are calls to dr_misalignment left that do not correct for the
    offset (which is vector type dependent) when the stride is negative.
    Notably vect_known_alignment_in_bytes doesn't allow to pass through
    such offset which the following adds (computing the offset in
    vect_known_alignment_in_bytes would be possible as well, but the
    offset can be shared as seen).  Eventually this function could go away.

    This leads to peeling for gaps not considerd, nor shortening of the
    access applied which is what fixes the testcase on x86_64.

            PR tree-optimization/118558
            * tree-vectorizer.h (vect_known_alignment_in_bytes): Pass
            through offset to dr_misalignment.
            * tree-vect-stmts.cc (get_group_load_store_type): Compute
            offset applied for negative stride and use it when querying
            alignment of accesses.
            (vectorizable_load): Likewise.

            * gcc.dg/vect/pr118558.c: New testcase.