return UNCHANGED;
return DefUseEffect.UNCHANGED;
  private static byte arrayLength(OPT_Instruction s) {    if (CF_FIELDS) {      OPT_Operand op = GuardedUnary.getVal(s);      if(op.isObjectConstant()) {        int length = Array.getLength(op.asObjectConstant().value);        Move.mutate(s, INT_MOVE, GuardedUnary.getClearResult(s),                    IC(length));        return MOVE_REDUCED;                } else if (op.isNullConstant()) {        // TODO: this arraylength operation is junk so destroy        return UNCHANGED;      }    }    return UNCHANGED;  }