https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77848
--- Comment #5 from Bill Schmidt <wschmidt at gcc dot gnu.org> --- I suppose that's not sensible as stated, as the SLP vectorizer doesn't really think in terms of loops. But this is an existing problem independent of whether we force loop-versioning on in all cases. Right now, a versioned loop that is not loop vectorized will not allow SLP vectorization on the if-converted version. We just don't happen to have test coverage that notices that.