https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89021
--- Comment #51 from Uroš Bizjak <ubizjak at gmail dot com> --- How about: Index: config/i386/i386.c =================================================================== --- config/i386/i386.c (revision 272656) +++ config/i386/i386.c (working copy) @@ -21380,6 +21380,9 @@ ix86_autovectorize_vector_sizes (vector_sizes *siz sizes->safe_push (16); sizes->safe_push (32); } + + if (TARGET_MMX_WITH_SSE) + sizes->safe_push (8); } /* Implemenation of targetm.vectorize.get_mask_mode. */