let ptr_cmp op l1 l2 =
match op with
| Lt -> D.lt_pointer_bool l1 l2
| Gt -> D.lt_pointer_bool l2 l1
| Le -> D.le_pointer_bool l1 l2
| Ge -> D.le_pointer_bool l2 l1
| Eq -> D.equal_pointer_bool l1 l2
| Ne -> F.e_not (D.equal_pointer_bool l1 l2)
| _ -> assert false