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_satisf:
forall ml e rs ls,
can_undef ml e = true ->
satisf rs ls e ->
satisf rs (undef_regs ml ls) e.