final void perform(OPT_IR ir) {
public final void perform(OPT_IR ir) {
  final void perform(OPT_IR ir) {    try {      // reset flags in case an exception is thrown inside "perform"      // and it doesn't return normally      ir.HIRInfo.postDominatorsAreComputed = false;      // compute post-dominators,       // leaves info in scratch object of basic blocks      OPT_LTDominators.perform(ir, false, unfactor);      // create the dominator tree, relies on dominator info being      // in scratch object of basic blocks      OPT_DominatorTree.perform(ir, false);      // computation completed, so set flag      ir.HIRInfo.postDominatorsAreComputed = true;    } catch (OPT_OperationNotImplementedException e) {      OPT_Options options = ir.options;      if (options.PRINT_POST_DOMINATORS) {        OPT_Compiler.report(e.getMessage());      }    }  }