https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63341
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I see non-NULL offset passed to vect_create_data_ref_ptr by vectorizable_store (for negative case), vectorizable_load (for this dr_explicit_realign_optimized), and to vect_create_addr_base_for_vector_ref in vect_gen_niters_for_prolog_loop (for negative case) and vect_create_cond_for_align_checks (also for negative case). So guess we'd need to check all these cases what we really want in those cases.
