https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111866
--- Comment #3 from Tamar Christina <tnfchris at gcc dot gnu.org> --- ok, so the crash looks like it's due to rgroups_control being empty during prologue peeling. It looks like the loop isn't masked so LOOP_VINFO_LENS (loop_vinfo) is being used in this case, but (!rgc->controls.is_empty ()) fails. As far as I can tell these are only filled in by vect_get_loop_len. It looks like after the refactoring vect_get_loop_len is not being called. It was expected to be called from vectorizable_store. Debugging why it doesn't get there.
