(** * Semantic preservation for instruction selection. *)
(** Relationship between the local environments. *)
Definition env_lessdef (e1 e2: env) : Prop :=
forall id v1, e1!id = Some v1 -> exists v2, e2!id = Some v2 /\ Val.lessdef v1 v2.

Lemma set_params_lessdef:
forall il vl1 vl2,
Val.lessdef_list vl1 vl2 ->
env_lessdef (set_params vl1 il) (set_params vl2 il).