template <typename InfoT>
class PerFunctionAggregateAnalysis {
 public:
  using Info = InfoT;

  // Returns the analysis info for the given function.
  const Info& GetAnalysisForFunc(func::FuncOp func) const {
    auto it = info_map_.find(func);
    assert(it != info_map_.end());
    return it->second;
  }

 protected:

    // them to skip side effect analysis.
    if (!func->hasAttr("ignore_side_effects_for_testing")) {
      info =
          &getAnalysis<mlir::TF::SideEffectAnalysis>().GetAnalysisForFunc(func);
    }
    func->walk([&](Operation* function) {
      for (Region& region : function->getRegions()) {
        for (Block& block : region.getBlocks()) {
          if (block.empty()) continue;

  for (auto func : module.getOps<func::FuncOp>()) {
    if (func.isExternal()) continue;
    OpBuilder builder(func.getContext());
    const TF::SideEffectAnalysis::Info& info =
        side_effect_analysis.GetAnalysisForFunc(func);

    // Operates on individual blocks independently of if they are directly in
    // the function body or if they are nested in individual
    // `tf_executor.island`.

  for (auto func : module_op.getOps<func::FuncOp>()) {
    if (func.isExternal()) continue;
    const auto& analysis_for_func =
        side_effect_analysis.GetAnalysisForFunc(func);
    if (failed(UpdateAllControlDependencies(func, analysis_for_func))) {
      signalPassFailure();
      return;
    }
  }
}

}  // namespace

  TF::SideEffectAnalysis side_effect_analysis(module);
  auto main_func = module.lookupSymbol<func::FuncOp>("main");
  const TF::SideEffectAnalysis::Info& info =
      side_effect_analysis.GetAnalysisForFunc(main_func);
  llvm::StringMap<SmallVector<Cluster>> clusters = BuildAllClusters(
      main_func.front(), info, GetDevice, CanBeIgnoredInCluster);
  return clusters;
}

TEST(BuildClusters, TestSingleCluster) {