https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113896
--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:2f16c53558d01135f0f78cf78a2f722b774684d7 commit r12-10155-g2f16c53558d01135f0f78cf78a2f722b774684d7 Author: Richard Biener <rguent...@suse.de> Date: Tue Feb 13 13:43:44 2024 +0100 tree-optimization/113896 - reduction of permuted external vector The following fixes eliding of the permutation of a BB reduction of an existing vector which breaks materialization of live lanes as we fail to permute the SLP_TREE_SCALAR_STMTS vector. PR tree-optimization/113896 * tree-vect-slp.cc (vect_optimize_slp): Permute SLP_TREE_SCALAR_STMTS when eliding a permuation in a VEC_PERM node we need to preserve because it wraps an extern vector. * g++.dg/torture/pr113896.C: New testcase.