https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81386
--- Comment #5 from Bill Schmidt <wschmidt at gcc dot gnu.org> --- The code is being vectorized in the "fails" dump and not being vectorized in the "works" dump. This cannot be due to r249424, which does gimple folding on some Power-specific built-ins, for this is a generic test case that makes no use of such built-ins. So either you have misidentified the revision responsible, or the code is somehow being compiled differently so that vectorization happens in one case and not the other. Bill