ir.HIRInfo.dominatorsAreComputed = false;
  static void staticPerform(OPT_IR ir) {    if (ir.hasReachableExceptionHandlers()) return;    // Note: the following unfactors the CFG.    OPT_DominatorsPhase dom = new OPT_DominatorsPhase(true);    boolean moreToCome = true;    while (moreToCome) {      dom.perform(ir);      moreToCome = turnWhilesIntoUntils(ir);    }    ensureLandingPads (ir);        dom.perform(ir);    ir.cfg.compactNodeNumbering();  }