for (const Edge* edge : node.in_edges()) {
    if (edge->IsControlEdge()) {
      deps->insert(edge->src());
    }
  }
}

// Adds the control outputs of `node` to `*deps`.
void AddControlOutputs(const Node& node, absl::flat_hash_set<Node*>* deps) {
  for (const Edge* edge : node.out_edges()) {
    if (edge->IsControlEdge()) {
      deps->insert(edge->dst());
    }
  }
}