Hint Rewrite is_pointer_or_null_force_int_ptr2 using assumption : norm1.

(* Specifications: *)
Lemma isptr_match : forall w0,
is_pointer_or_null
match
match w0 with
| Vint _ => if Archi.ptr64 then None else Some w0
| Vlong _ => if Archi.ptr64 then Some w0 else None
| Vptr _ _ => Some w0
| _ => None
end
with
| Some v' => v'
| None => Vundef
end
= is_pointer_or_null w0.