(** Compatibility of evaluation functions with the "less defined than" relation. *)
Ltac TrivialExists :=
match goal with
| [ |- exists v, Some ?x = Some v /\ _ ] => exists x; split; auto
| _ => idtac
end.
(*Lemma eval_unop_lessdef: forall op v1 v1' v, eval_unop op v1 = Some v -> Val.lessdef v1 v1' -> exists v', eval_unop op v1' = Some v' /\ Val.lessdef v v'.  (** Lenb: replace eval_unop_lessdef with eval_unop from Cminorgenproof; this requires the additio of Require Import Float above Compatibility of [eval_unop] with respect to [val_inject]. *)

Lemma eval_unop_compat:
forall f op v1 tv1 v,
eval_unop op v1 = Some v ->
val_inject f v1 tv1 ->
exists tv,
eval_unop op tv1 = Some tv
/\ val_inject f v tv.