private static byte refNot(OPT_Instruction s) {
private static DefUseEffect refNot(OPT_Instruction s) {
  private static byte refNot(OPT_Instruction s) {   if (CF_ADDR) {      OPT_Operand op = Unary.getVal(s);      if (op.isAddressConstant()) {        // CONSTANT: FOLD        Word val = op.asAddressConstant().value.toWord();        Move.mutate(s, REF_MOVE, Unary.getClearResult(s), AC(val.not().toAddress()));        return MOVE_FOLDED;      }    }    return UNCHANGED;  }