s.operator == REF_ADD || s.operator == REF_SUB ||
  private static OPT_Register isCandidateExpression(OPT_Instruction s) {    if (s.operator == INT_ADD || s.operator == LONG_ADD ||        s.operator == INT_SUB || s.operator == LONG_SUB ) {      OPT_Operand val2 = Binary.getVal2(s);      if (val2.isConstant()) {        OPT_Operand val1 = Binary.getVal1(s);        // if val1 is constant too, this should've been constant folded        // beforehand.  Give up.        if (val1.isConstant()) return null;        return Binary.getResult(s).asRegister().register;      }    }    return null;  }