Ltac UseGetSound :=
  match goal with
  | [ H: get _ = Some _ |- _ ] =>
      let x := fresh "EQ" in (generalize (get_op_sound _ _ _ H); intros x; simpl in x; FuncInv)
  end.

Theorem combine_op_sound: forall op args op' args', combine_op get op args = Some(op', args') -> eval_operation ge sp op' (map valu args') m = eval_operation ge sp op (map valu args) m.