VM._assert(op instanceof OPT_StringConstantOperand);
VM._assert(op.isStringConstant() || op.isClassConstant());
  public static OPT_Operand getGuard(OPT_Operand op) {    if (op instanceof OPT_RegisterOperand) {      OPT_RegisterOperand rop = (OPT_RegisterOperand)op;      if (VM.VerifyAssertions) {        VM._assert((rop.scratchObject == null) ||                   (rop.scratchObject instanceof OPT_RegisterOperand)                  || (rop.scratchObject instanceof OPT_TrueGuardOperand));      }		if(rop.scratchObject == null) {		  return null;		}		else {		  return ((OPT_Operand)rop.scratchObject).copy();		}    }    if (VM.VerifyAssertions)      VM._assert(op instanceof OPT_StringConstantOperand);    return new OPT_TrueGuardOperand();  }