[Bug tree-optimization/126862] [17 Regression] ICE: verify_ssa failed for PHI node during GIMPLE pass: slp with -O3 -ftree-slp-vectorize -fvect-cost-model=unlimited

"cvs-commit at gcc dot gnu.org via Gcc-bugs" <[email protected]> Fri, 14 Aug 2026 10:29:58 +0000

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126862

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <[email protected]>:

https://gcc.gnu.org/g:2026474385dc23e9896577db08d963bc3a96f256

commit r17-3285-g2026474385dc23e9896577db08d963bc3a96f256
Author: Richard Biener <[email protected]>
Date:   Fri Aug 14 11:14:00 2026 +0200

    tree-optimization/126862 - fix live lane extract dominance check for PHIs

    We were not correctly verifying dominance of the vector definition
    with the scalar use in case of PHI use stmts.  We have to ensure
    the respective PHI edge source can reach the definition.

            PR tree-optimization/126862
            * tree-vect-slp.cc (vect_bb_slp_mark_live_stmts): For PHI
            uses verify dominance to the PHI use edge source.

            * gcc.dg/vect/bb-slp-pr126862.c: New testcase.