message: Avoid taking a reference on a temporary value
diff: @@ -368,7 +368,7 @@ Status LoopOptimizer::FindInvariantNodes(NodeDef* node) {
  bool is_invariant = true;
  for (const auto& input : consumer->input()) {
  if (!IsControlInput(input)) {
  - const auto& name = NodeName(input);
  + const string name = NodeName(input);
  auto* producer = node_map_->GetNode(name);
  if (!invariant_nodes_.count(producer)) {
  if (IsConstant(*producer)) {
  