[Bug tree-optimization/123038] [16 Regression] ICE at O3 during GIMPLE pass: vect

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123038

--- Comment #5 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:5584b489341924d042988ad27a2dc25fa8fda62a

commit r16-5957-g5584b489341924d042988ad27a2dc25fa8fda62a
Author: Richard Biener <rguenther@suse.de>
Date:   Sun Dec 7 11:30:48 2025 +0100

    tree-optimization/123038 - FFS/CTZ pattern incompatible with reductions

    The pattern ends up using the argument more than one time which
    isn't supported.  When FFS directly maps to CTZ + 1 it works though.

            PR tree-optimization/123038
            * tree-vect-patterns.cc (vect_recog_ctz_ffs_pattern): Reject
            pattern for reductions when the call argument is used multiple
            times.

            * gcc.dg/vect/pr123038.c: New testcase.