(* Lemma unchanged_on_sym P m m' b: Mem.unchanged_on P m m' -> Mem.valid_block m b -> Mem.unchanged_on (fun bb z => P bb z /\ bb=b) m' m. *)

Lemma val_listless_forall_lessdef:
forall args args' (H:Val.lessdef_list args args'),
Forall2 Val.lessdef args args' .