https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96163
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- OK, so the issue is that the representation for pre-existing vectors leaves us with vector defs outside of the region (and not immediately before the region begin) which then confuses the logic in vect_stmt_dominates_stmt_p. I need to think a bit about this.
