Definition rolm_redundant (x: nval) (amount mask: int) :=
Int.eq_dec amount Int.zero && andimm_redundant x mask.

Lemma rolm_redundant_sound:
forall v w x amount mask,
rolm_redundant x amount mask = true ->
vagree v w (rolm x amount mask) ->
vagree (Val.rolm v amount mask) w x.