https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107212
--- Comment #8 from CVS 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:d127348d7711e148e5ddd205a8c3409b37fae64c commit r12-8840-gd127348d7711e148e5ddd205a8c3409b37fae64c Author: Richard Biener <rguent...@suse.de> Date: Tue Oct 11 11:34:55 2022 +0200 tree-optimization/107212 - SLP reduction of reduction paths The following fixes an issue with how we handle epilogue generation for SLP reductions of reduction paths where the actual live lanes are not "canonical". We need to make sure to identify all live lanes as reductions and thus have to iterate over all participating SLP lanes when walking the reduction SSA use-def chain. Also the previous attempt likely to mitigate such issue in vectorizable_live_operation is misguided and has to be removed. PR tree-optimization/107212 * tree-vect-loop.cc (vectorizable_reduction): Make sure to set STMT_VINFO_REDUC_DEF for all live lanes in a SLP reduction. (vectorizable_live_operation): Do not pun to the SLP node representative for reduction epilogue generation. * gcc.dg/vect/pr107212-1.c: New testcase. * gcc.dg/vect/pr107212-2.c: Likewise. (cherry picked from commit ee467644c53ee2f7d633a8e1f53603feafab4351)
