https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84777
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- Hmm, patch can't help. Instead try the following which should make the omp simd case work. Index: gcc/tree-ssa-loop-ch.c =================================================================== --- gcc/tree-ssa-loop-ch.c (revision 258380) +++ gcc/tree-ssa-loop-ch.c (working copy) @@ -57,7 +57,8 @@ should_duplicate_loop_header_p (basic_bl be true, since quite often it is possible to verify that the condition is satisfied in the first iteration and therefore to eliminate it. Jump threading handles these cases now. */ - if (optimize_loop_for_size_p (loop)) + if (optimize_loop_for_size_p (loop) + && !loop->force_vectorize) { if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file,