message: Fix latent bug in dependency optimizer.
diff: @@ -97,7 +97,12 @@ bool DependencyOptimizer::SafeToRemoveIdentity(const NodeDef& node) {
  // TODO(rmlarsen): Try to remove this artificial contraint.
  return false;
  }
  + }
  for (auto consumer : node_map_->GetOutputs(node.name())) {
  + if (node.input_size() > 1 && IsMerge(*consumer)) {
  + return false;
  + }
  + if (IsSwitch(*input)) {
  for (const string& consumer_input : consumer->input()) {
  if (consumer_input == AsControlDependency(node.name())) {
  return false;
  