(** Inclusion *)
Definition vpincl (v: aval) (p: aptr) : bool :=
match v with
| Ptr q | Ifptr q | Uns q _ | Sgn q _ => pincl q p
| _ => true
end.

Lemma vpincl_sound:
forall v x p, vpincl x p = true -> vmatch v x -> vmatch v (Ifptr p).