if (a.TypeId() == tensorflow::TypeIndex::Make<::tensorflow::TensorList>()) {
    TF_RETURN_IF_ERROR(ValidateVariantType<::tensorflow::TensorList>(a));
    *out = ::tensorflow::TensorList();

    return ::tensorflow::TensorListBinaryAdd(
        cc_ctx, *a.get<::tensorflow::TensorList>(),
        *b.get<::tensorflow::TensorList>(),
        out->get<::tensorflow::TensorList>(), cc_binary_add);

      });
  return has_variant_input || has_variant_output;
}

// There are 2 standard tf ops which are not TensorList ops that may take as
// input a tensorlist. These are tf.AddN and tf.ZeroesLike. Since the runtime
// implementation of a tensorlist are not compatible between tf and tflite
// we cannot use tflite tensorlist kernels until these cases are handled.
bool IsNonTensorListVariantOp(Operation* op) {

    // meaningless value -1 for non resource outputs.
    out_desc.input_index =
        it != output_to_input_alias.end() ? it->getSecond() : -1;
    // MLIR-based TF-Compiler bridge doesn't support tensorlist output yet.
    // TODO(ycao): Support tensorlist-type output.
    out_desc.is_tensor_list = false;
  }

  // XLA computation always uses Tuple shape.
  *xla_output_shape = xla::ShapeUtil::MakeTupleShape(shapes);

             "legalized by this pass, then the IR won't be changed so that "
             "tensorlist ops can pass through (default false).">,
      Option<
        "default_to_single_batch_", "default-to-single-batch", "bool", "false",
        "When specified to true, if the tensorlist ops has unspecified batch "
        "size, this pass will assume that the batch size is one to proceed "

  OpBuilder builder(list);
  llvm::SmallVector<int64_t, 8> element_shape;
  // Infer TensorList element shape from the return type first, and then from
  // the const element shape operand. We first check the return type because
  // shape inference might have successfully inferred the element shape from
  // write operations on the TensorList.
  if (failed(GetElementShapeFromResultType(list.getType(), &element_shape))) {

// Creates a pass that adds control dependencies to keep the relative execution
// order of operations with side effects frozen.
std::unique_ptr<OperationPass<func::FuncOp>> CreatePinOpsWithSideEffectsPass();

// Legalize TensorList Ops iff all of them are supported.
std::unique_ptr<OperationPass<ModuleOp>> CreateLegalizeTensorListPass();

// Reduce the type precision of some tensor types if all values within that

                .getDimSize(1),
            3);

  auto it = fused_lstm_func_.getBody().back().rbegin();
  EXPECT_EQ(it->getName().getStringRef(),
            mlir::func::ReturnOp::getOperationName());
  it++;  // tensor_cast
  it++;  // lstm
  EXPECT_EQ(it->getName().getStringRef(),
            mlir::TFL::LSTMOp::getOperationName());
  EXPECT_EQ(it->getNumOperands(), 24);
  EXPECT_EQ(it->getNumResults(), 1);

// RUN: tf-opt "-tfl-lower-static-tensor-list=allow-tensorlist-pass-through default-to-single-batch" -split-input-file %s | FileCheck %s

// -----

// CHECK-LABEL: tensorlistConst
func.func @tensorlistConst(%arg0 : tensor<1xi32>) -> tensor<2x3xi32> {
  // CHECK-DAG: %[[ELEMENT0:.*]] = "tf.Const"() <{value = dense<[0, 1, 2]> : tensor<3xi32>}> : () -> tensor<3xi32>

  }

  for (const XlaOutputDescription& descr : compilation_result->outputs) {
    if (descr.type == DT_VARIANT) {
      return errors::Unimplemented(
          "Support for TensorList crossing the XLA/TF boundary "
          "is not implemented");
    }
  }

  std::vector<TensorShape> output_tensor_shapes;
  output_tensor_shapes.reserve(ctx->num_outputs());

    const int64_t id = target_tensor_ids[i];
    if (output_gradients.empty() || output_gradients[i] == nullptr) {
      auto tensor_it = tensor_tape.find(id);
      if (tensor_it != tensor_tape.end() && tensor_it->second != -1) {
        auto op_it = op_tape.find(tensor_it->second);
        if (op_it == op_tape.end()) {
          return errors::Internal(
              "Internal state of the gradient tape is invalid: "