Definition orimm_redundant (x: nval) (n: int) :=
match x with
| Nothing => true
| I m => Int.eq_dec (Int.and m n) Int.zero
| _ => false
end.

Lemma orimm_redundant_sound:
forall v w x n,
orimm_redundant x n = true ->
vagree v w (orimm x n) ->
vagree (Val.or v (Vint n)) w x.