Remark val_lessdef_normalize:
  forall v v' ty,
  Val.has_type v ty -> Val.lessdef v v' ->
  Val.lessdef v (Val.load_result (chunk_of_type ty) v').

Lemma can_undef_sound: forall e ml q, can_undef ml e = true -> EqSet.In q e -> Loc.notin (eloc q) (map R ml).