// iterator_traits defined and so on.
  std::vector<Node*> sorted_nodes;
  for (Node* node : graph_->op_nodes()) {
    sorted_nodes.push_back(node);
  }
  std::sort(sorted_nodes.begin(), sorted_nodes.end(), NodeComparatorID());

  if (*debug_options_.fuel >= std::numeric_limits<int64_t>::max() / 2) {
    // The assumption is that if fuel started out as INT64_MAX, it will forever
    // stay greater than INT64_MAX / 2.