For example, a non replicated `tf_device.cluster_func`:

    ```mlir
    func @tf_tpu_rewrite(%arg0: tensor<i8>) {
      %0 = "tf_device.cluster_func"(%arg0) {_xla_compile_device_type = "TPU", _replication_info = "cluster0", func = @func} : (tensor<i8>) -> tensor<i8>
      return
    }
    ```

    will be rewritten as:

    ```mlir
    func @tf_tpu_rewrite(%arg0: tensor<i8>) {

  func.func @main() {

  // CHECK-LABEL: @converts_cluster
  func.func @converts_cluster() {
    // CHECK: "tf.XlaLaunch"()

  func.func @main(%arg0: tensor<*xf32> {tf.device = "/job:localhost/replica:0/task:0/device:CPU:0"}) {

// Verifies that all MLIR Ops have the expected attributes.
std::unique_ptr<mlir::OperationPass<mlir::func::FuncOp>>
CreateVerifyClusteringPass();

// Creates a pass that forms clusters from operations of the same
// `_replication_info` attribute.
std::unique_ptr<mlir::OperationPass<mlir::ModuleOp>>
CreateTPUClusterFormationPass(bool strict_clusters = false);

// Creates a pass that extracts outside compilation (Host ops inside device

```

wll be replaced by `_replication_info="cluster"` and  `_xla_compile_device_type="TPU"`.

```mlir

// This transformation pass converts existing compilation and replication
// attributes into unified attributes. For example, A _tpu_replicate=X
// should be replaced with _xla_compile_device_type=TPU and
// _replication_info=X attributes by the conversion. An _XlaMustCompile=true
// should be replaced with _xla_compile_device_type with the value of device
// attribute.

#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Debug.h"

            tf_device.return %4#0, %4#1 : tensor<2048xi32>, tensor<2048xi32>
            }) {device = "TPU_REPLICATED_HOST_0"} : () -> (tensor<2048xi32>, tensor<2048xi32>)
      %1 = "tf_device.cluster_func"(%0#0, %0#1) {_replication_info = "cluster_test_fn", func = @tpu_func} : (tensor<2048xi32>, tensor<2048xi32>) -> tensor<2048xi32>
      return %1: tensor<2048xi32>
   }
   // CHECK-LABEL: func @tpu_func
   // CHECK: mhlo.type_extensions

==============================================================================*/

// This transformation pass converts unified compilation and replication
// attributes into legacy attributes. For example,  _replication_info=X
// and _xla_compile_device_type=TPU should be replaced with _tpu_replicate=X.
// This ensures the unified attributes not get exposed outside of the MLIR
// bridge with V1 pipeline in some cases.

    "_cluster_outlined_function_name";
// Marks a node for replication. The attribute value indicates the replication
// metadata op.
inline constexpr llvm::StringRef kReplicationInfoAttr = "_replication_info";
// Marks a node for XLA-TPU compilation. The attribute value indicates the
// associated compilation cluster and replication metadata op.
inline constexpr llvm::StringRef kTpuReplicateAttr = "_tpu_replicate";