https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81877
--- Comment #13 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
> More rigorously defining the semantic of loop->safelen (the
> middle-end term) is necessary nevertheless. I believe omp ordered
> doesn't have any middle-end representation?
Except on nvptx, 'omp ordered' in omp-simd context becomes a stmt sequence
bracketed with IFN_GOMP_SIMD_ORDERED_{START,END}, which completely disables
cross-iteration vectorization aiui. So your example doesn't get vectorized (not
even with SLP).
(on omp/ptx the approach is different)
