[Bug tree-optimization/121256] [13/14/15 Regression] ffmpeg miscompiled with -O2 -march=znver2 since r13-3327-g46a8e017d048ec

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121256

--- Comment #10 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-15 branch has been updated by Richard Biener
<rgue...@gcc.gnu.org>:

https://gcc.gnu.org/g:e442d6f4964daec3c9dfeb52101d9f80ff363f27

commit r15-10167-ge442d6f4964daec3c9dfeb52101d9f80ff363f27
Author: Richard Biener <rguent...@suse.de>
Date:   Sun Jul 27 18:42:25 2025 +0200

    tree-optimization/121256 - properly support SLP in vectorizable recurrence

    We failed to build the correct initialization vector.  For VLA
    vectors and a non-uniform initialization vector this rejects
    vectorization for now.

            PR tree-optimization/121256
            * tree-vect-loop.cc (vectorizable_recurr): Build a correct
            initialization vector for SLP_TREE_LANES > 1.

            * gcc.dg/vect/vect-recurr-pr121256.c: New testcase.
            * gcc.dg/vect/vect-recurr-pr121256-2.c: Likewise.

    (cherry picked from commit 26dc9aa285b53551c55d3d660bb6da21d59d7023)