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_cond_sound: forall cond args cond' args', combine_cond get cond args = Some(cond', args') -> eval_condition cond' (map valu args') m = eval_condition cond (map valu args) m.