public static void perform(OPT_IR ir, boolean forward) {
public static void perform(OPT_IR ir, boolean forward, boolean unfactor) {
  public static void perform(OPT_IR ir, boolean forward) {    if (ir.hasReachableExceptionHandlers()) {      if (ir.options.UNFACTOR_FOR_SSA) {        ir.unfactor();       } else {        throw  new OPT_OperationNotImplementedException(            "IR with exception handlers");      }    }    OPT_LTDominators dom = new OPT_LTDominators(ir, forward);  }