// an `_XlaCluster` attribute.  Also some basic filter logic, like
  // tf_xla_min_cluster_size, are applied here.
  Status CreateClusters();

  Status DumpDebugInfo();

  bool IsCompilationCandidate(Node* n) const {
    return compilation_candidates_.find(n) != compilation_candidates_.end();
  }

  // Tries to contract the edge from cluster `from` to cluster `to`.  Returns