if (debug_options_.dump_graphs) {
    DumpGraphToFile("before_mark_for_compilation", *graph_, flib_def_);
  }

  // Mark clusters for compilation that:
  // * are placed on a device that requires compilation (an XlaDevice),
  // * are explicitly marked for compilation (_XlaCompile=true), or
  // * have more than debug_options_.xla_min_cluster_size elements (applicable
  //   only if compilation is enabled, otherwise there will be no such