absl::flat_hash_set<std::pair<int, int>> unsafe_resource_deps_;
};

std::vector<int> MarkForCompilationPassImpl::FindAlternatePathForDebugging(
    int from, int to) {
  std::vector<int> rpo = cycles_graph_.AllNodesInPostOrder();
  absl::c_reverse(rpo);

  // best_pred_for_node[n] contains a predecessor of `n` that has an
  // unclusterable node in some path from `from` to itself.