}
};

// Finds first inner op if `op` is a tf_executor.island. Otherwise `op` is
// returned.
Operation* GetIslandInnerOpOrSelf(mlir::Operation* op) {
  auto island = llvm::dyn_cast<mlir::tf_executor::IslandOp>(op);
  if (island) return &island.GetBody().front();
  return op;
}

// Stateful helper class to export a function into a Graph.
class Exporter {
 public:

// This is a V1 backward compatibility.
std::unique_ptr<OperationPass<ModuleOp>>
CreateTFExecutorTPUV1IslandCoarseningPass();

// Creates a pass to outlining TPU clusters from single IslandOp into a nested
// module suitable for being processed as-if it was a V2 module.
// This is a V1 backward compatibility.
std::unique_ptr<OperationPass<ModuleOp>>
CreateTFExecutorTPUV1IslandOutliningPass();

  return isa<tf_device::ReturnOp, tf_device::ClusterOp, tf_device::LaunchOp,
             tf_executor::EnterOp, tf_executor::ExitOp, tf_executor::FetchOp,
             tf_executor::GraphOp, tf_executor::IslandOp,
             tf_executor::LoopCondOp, tf_executor::MergeOp,
             tf_executor::NextIterationSinkOp, tf_executor::SwitchNOp,
             tf_executor::SwitchOp, tf_executor::YieldOp>(op) ||