intros.
unfold is_pointer_or_null.
destruct Archi.ptr64 eqn:Hp;
destruct w0; auto.
Qed.
Hint Rewrite isptr_match : norm1.

Lemma eval_cast_neutral_tc_val:
forall v, (exists t, tc_val t v /\ is_pointer_type t = true) ->
sem_cast_pointer v = Some v.