// connected but sometimes the incoming graph does not follow this invariant.
  // So fix up the source and sink edges before calling into deadness analysis.
  FixupSourceAndSinkEdges(graph);

  for (Node* n : graph->nodes()) {
    // See explanation on `kXlaAlreadyClustered`.
    if (n->attrs().Find(kXlaAlreadyClustered)) {
      return absl::OkStatus();
    }

    }
  }

  // Since we might have inserted and removed nodes from the graph, fix
  // source/sink edges and reconstruct the RPO ordering of nodes
  FixupSourceAndSinkEdges(graph_.get());

  // Prune nodes in the graph that are not reachable from the output.
  if (specs_.prune_unused_nodes) {
    std::unordered_set<const Node*> prune_start;