VM._assert(false);
if (VM.VerifyAssertions) VM._assert(false);
  static OPT_Operand asImmediateOrRegLong(OPT_Operand addr,                                      OPT_Instruction s,                                      OPT_IR ir, boolean signed) {    if (VM.BuildFor64Addr && (addr instanceof OPT_LongConstantOperand)) {      if (!canBeImmediate(((OPT_LongConstantOperand)addr).value, signed)) {        OPT_RegisterOperand rop = ir.regpool.makeTempLong();        s.insertBefore(Move.create(REF_MOVE, rop, addr));        return rop.copyD2U();      } else { // can be immediate --> convert to int        return new OPT_IntConstantOperand((int)((OPT_LongConstantOperand)addr).value);      }    }    else if (addr instanceof OPT_ConstantOperand) {      VM._assert(false); //must not happen    }        // Operand was OK as is.    return addr;  }