private void filterOnExceptionRanges(DominatorTreeExceptionFilter filter) {
    for (Integer head : new HashSet<>(mapExtPostdominators.keySet())) {
      FastFixedSet<Integer> set = mapExtPostdominators.get(head);
      for (Iterator<Integer> it = set.iterator(); it.hasNext(); ) {
        if (!filter.acceptStatementPair(head, it.next())) {
          it.remove();
        }
      }
      if (set.isEmpty()) {
        mapExtPostdominators.remove(head);
      }
    }
  }
private void filterOnExceptionRanges(DominatorTreeExceptionFilter filter)