Hint Rewrite is_pointer_or_null_force_int_ptr using assumption : norm1.

(* Specifications: *)
Lemma is_pointer_force_int_ptr:
forall v, isptr v -> (force_val
match v with
| Vint _ => if Archi.ptr64 then None else Some v
| Vlong _ => if Archi.ptr64 then Some v else None
| Vptr _ _ => Some v
| _ => None
end) = v.