Require Export VST.veric.environ_lemmas.
Require Export VST.veric.expr_lemmas3.
(** Main soundness result for the typechecker **)
Ltac unfold_cop2_sem_cmp :=
unfold Clight_Cop2.sem_cmp, Clight_Cop2.sem_cmp_pl, Clight_Cop2.sem_cmp_lp, Clight_Cop2.sem_cmp_pp.
(*        (Hcenv: genv_cenv ge = @cenv_cs CS)*)
Definition some_pt_type := Tpointer Tvoid noattr.
Opaque tc_andp.
(** Equivalence of CompCert eval_expr and our function eval_expr on programs that typecheck **)
Ltac destruct_eqb_type :=
match goal with H: context [eqb_type ?t1 ?t2] |- _ =>
let J := fresh "J" in
destruct (eqb_type t1 t2) eqn:?J;
[apply eqb_type_true in J | apply eqb_type_false in J]
end.
Definition cast_pointer_to_bool t1 t2 :=
match t1 with (Tpointer _ _ | Tarray _ _ _ | Tfunction _ _ _) =>
match t2 with Tint IBool _ _ => true | _ => false end
| _ => false
end.

Lemma sem_cast_e1:
forall t t1 v1 v m,
sem_cast t t1 v = Some v1 ->
cast_pointer_to_bool t t1 = false ->
tc_val t v ->
Cop.sem_cast v t t1 m = Some v1.