Function RemoveIdentityNodes

tensorflow/core/common_runtime/function.cc:1377–1408

}  // end namespace

bool RemoveIdentityNodes(Graph* g) {
  VLOG(2) << "Removing identity nodes";
  bool removed_any = false;
  gtl::InlinedVector<Node*, 8> matches;
  for (Node* n : g->nodes()) {
    if (!n->IsIdentity()) continue;
    if (!GetTheOnlyDataEdge(n->in_edges())) continue;

    // Some identity nodes are used as sink nodes to give names to output
    // tensors. These nodes are not going to be executed unless they are in the
    // fetch set. But if they are in the fetch set we don't want to remove them.
    if (n->out_edges().empty()) continue;

    matches.push_back(n);
  }
  if (!matches.empty()) {
    for (Node* n : matches) {
      const Edge* in = GetTheOnlyDataEdge(n->in_edges());
      for (const Edge* out : n->out_edges()) {
        if (out->IsControlEdge()) {
          g->AddControlEdge(in->src(), out->dst());
        } else {
          g->AddEdge(in->src(), in->src_output(), out->dst(), out->dst_input());
        }
      }
      VLOG(2) << "Remove Identity: " << n->DebugString();
      g->RemoveNode(n);
      removed_any = true;
    }
  }
  return removed_any;
}

bool RemoveListArrayConverter(Graph* g) {
  VLOG(2) << "Removing list array converter";