Definition unOp_result_type op t :=
match op with
  | Cop.Onotbool =>match t with
                                | Tint _ _ _ => Tint IBool Signed noattr
                                | Tlong _ _ => Tint IBool Signed noattr
                                | Tpointer _ _ => Tint I32 Signed noattr
                                | Tfloat _ _ => Tint IBool Signed noattr
                                | Tarray _ _ _ => Tint IBool Signed noattr
                                | Tfunction _ _ _ => Tint IBool Signed noattr
                                | _ => Tvoid
                                end
  | Cop.Onotint => match t with
                                | Tint _ _ _ => Tint I32 Signed noattr
                                | Tlong _ _ => Tlong Signed noattr
                                | _ => Tvoid
                                end
  | Cop.Oneg => match t with
                           | Tint _ _ _ => Tint I32 Signed noattr
                           | Tlong _ _ => Tlong Signed noattr
                           | Tfloat _ _ => t
                           | _ => Tvoid
                           end
  | Cop.Oabsfloat => t
end.

Lemma same_base_tc_val : forall v t1 t2, same_base_type t1 t2 = true -> tc_val t1 v -> tc_val t2 v.