https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121631
--- Comment #3 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:ef8b3b979b6117eba9b39a7174f89b7297e8a1cd commit r16-4500-gef8b3b979b6117eba9b39a7174f89b7297e8a1cd Author: Richard Biener <[email protected]> Date: Fri Oct 17 14:03:21 2025 +0200 tree-optimization/121631 - UB in vector epilogue The vectorizer fails to take UB due to signed overflow into account when generating code for the epilogue of a signed reduction. The following tries to make sure to perform the actual reduction computations in an unsigned type. I did not bother to adjust inputs to internal functions like .REDUC_PLUS. PR tree-optimization/121631 * tree-vect-loop.cc (vect_create_epilog_for_reduction): When the reduction operation invokes UB on signed overflow make sure to perform operations with it on an unsigned type.
