//   We don't need to do anything special.
  if (!sequencer->in_edges().empty()) {
    (*host_graph)->AddControlEdge(sequencer, (*host_graph)->sink_node());
  }
  PruneForReverseReachability(
      host_graph->get(),
      std::unordered_set<const Node*>{(*host_graph)->sink_node()});

  // Postprocess edges between different outside compilations.

  if (specs_.prune_unused_nodes) {
    std::unordered_set<const Node*> prune_start;
    TF_RETURN_IF_ERROR(GetInputOutputNodes(*node_name_map, &prune_start));
    if (!prune_start.empty()) {
      if (PruneForReverseReachability(graph_.get(), prune_start)) {
        VLOG(1) << "Pruned unused nodes in graphdef";
      } else {
        VLOG(1) << "No unused nodes in graphdef to prune";
      }
    } else {