VM._assert(false);
if (VM.VerifyAssertions) VM._assert(false);
  static OPT_Operand asRegLong(OPT_Operand addr,                           OPT_Instruction s,                           OPT_IR ir) {    if (VM.BuildFor64Addr && (addr instanceof OPT_LongConstantOperand)) {      OPT_RegisterOperand rop = ir.regpool.makeTempLong();      s.insertBefore(Move.create(REF_MOVE, rop, addr));      return rop.copyD2U();    }    else if (addr instanceof OPT_ConstantOperand) {      VM._assert(false); //must not happen    }    // Operand was OK as is.    return addr;  }