OPT_Instruction dummy = Load.create(INT_LOAD,null,null,null,null);
  private void prependStore(OPT_BasicBlock bb, OPT_IR ir) {    if (DEBUG)VM.sysWrite("Adding store to "+ bb + "\n");    OPT_Instruction store = null;    if (ir.options.PROCESSOR_SPECIFIC_COUNTER) {      OPT_Instruction dummy = Load.create(INT_LOAD,null,null,null,null);      store = Store.create(INT_STORE,                            cbsReg.copyRO(),                           OPT_IRTools.A(ir.regpool.getPhysicalRegisterSet().getPR()),                           OPT_IRTools.AC(VM_Entrypoints.processorCBSField.getOffset()),                           new OPT_LocationOperand(VM_Entrypoints.processorCBSField));      bb.prependInstruction(store);    }    else {      if (ir.IRStage == OPT_IR.HIR) {        store = PutStatic.create(PUTSTATIC,cbsReg.copyRO(),new OPT_AddressConstantOperand(VM_Entrypoints.globalCBSField.getOffset()),                                 new OPT_LocationOperand(VM_Entrypoints.globalCBSField));                bb.prependInstruction(store);      } else {        OPT_Instruction dummy = Load.create(INT_LOAD,null,null,null,null);        bb.prependInstruction(dummy);        store = Store.create(INT_STORE,                              cbsReg.copyRO(),                             ir.regpool.makeJTOCOp(ir,dummy),                              OPT_IRTools.AC(VM_Entrypoints.globalCBSField.getOffset()),                             new OPT_LocationOperand(VM_Entrypoints.globalCBSField));                dummy.insertBefore(store);        dummy.remove();      }    }     }    