if (op != null && op.isRegister() && !op.asRegister().register.isPhysical()) { recordUse(op.asRegister());
if (op instanceof OPT_RegisterOperand) { recordUse((OPT_RegisterOperand)op);
  static void updateDUForNewInstruction(OPT_Instruction s) {    for (OPT_OperandEnumeration e = s.getPureDefs(); e.hasMoreElements();) {      OPT_Operand op = e.next();      if (op != null && op.isRegister() &&           !op.asRegister().register.isPhysical()) {        recordDef(op.asRegister());      }    }    for (OPT_OperandEnumeration e = s.getUses(); e.hasMoreElements();) {      OPT_Operand op = e.next();      if (op != null && op.isRegister() &&           !op.asRegister().register.isPhysical()) {        recordUse(op.asRegister());      }    }  }