https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71264
--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> --- Ah, it has V4QI, not SImode ... and thus it triggers if (VECTOR_MODE_P (TYPE_MODE (gimple_expr_type (stmt)))) { if (dump_enabled_p ()) { dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, "not vectorized: vector stmt in loop:"); dump_gimple_stmt (MSG_MISSED_OPTIMIZATION, TDF_SLIM, stmt, 0); dump_printf (MSG_MISSED_OPTIMIZATION, "\n"); } return false; } I'll think about this a bit. I don't think we have a good dejagnu target to check here :/ (not-vector-size-4B) Looks like even x86 has V4QI but it is not being used here for some reason - it's never a targetm.vector_mode_supported_p mode.