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 compat_left2_sound:
forall r l1 l2 e q,
compat_left2 r l1 l2 e = true -> EqSet.In q e -> ereg q = r ->
(ekind q = High /\ eloc q = l1) \/ (ekind q = Low /\ eloc q = l2).