// This is an "top-level" outside compilation. Clear the graph, and copy
    // SendFromHost and all its predecessors from `host_graph`.
    std::vector<Node*> nodes;
    nodes.reserve(g->num_op_nodes());
    for (Node* n : g->op_nodes()) {
      nodes.push_back(n);
    }
    for (Node* n : nodes) {
      g->RemoveNode(n);
    }