https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121758
--- Comment #7 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:41e2fe9be1ff5ef2eafd49b30882898d26b9bf36 commit r16-3538-g41e2fe9be1ff5ef2eafd49b30882898d26b9bf36 Author: Richard Biener <[email protected]> Date: Wed Sep 3 10:04:58 2025 +0200 tree-optimization/121758 - fix pattern stmt REDUC_IDX updating The following fixes a corner case of pattern stmt STMT_VINFO_REDUC_IDX updating which happens auto-magically. When a 2nd pattern sequence uses defs from inside a prior pattern sequence then the first guess for the lookfor can be off. This happens when for example widening patterns use vect_get_internal_def, which looks into earlier patterns. PR tree-optimization/121758 * tree-vect-patterns.cc (vect_mark_pattern_stmts): Try harder to find a reduction continuation. * gcc.dg/vect/pr121758.c: New testcase.
