message: Log more info about the ill-formed node in ComputeTransitiveFanin.
diff: @@ -134,6 +134,7 @@ std::vector<const NodeDef*> ComputeTransitiveFanin(
  const NodeDef* node = name_to_node[NodeName(root)];
  if (!node) {
  *ill_formed = true;
  + VLOG(2) << "ComputeTransitiveFanin: problem with root node: " << root;
  return {};
  }
  queue.push_back(node);
  @@ -153,6 +154,7 @@ std::vector<const NodeDef*> ComputeTransitiveFanin(
  for (const string& input : node->input()) {
  const NodeDef* in = name_to_node[NodeName(input)];
  if (!in) {
  + VLOG(2) << "ComputeTransitiveFanin: problem with node: " << input;
  *ill_formed = true;
  return {};
  }
  