return mlir::isa<mlir::TF::TensorFlowRefType>(
        mlir::getElementTypeOrSelf(next_iter_sink.getInput().getType()));

  auto op_name_or_status = GetTensorFlowOpName(op->getName().getStringRef());
  if (!op_name_or_status.ok()) return false;

  auto op_name = std::move(op_name_or_status).value();
  if (op_name == "NextIteration")

Status AddTensorFlowOpPrefix(std::string);

// Maps an MLIR op name in the TensorFlow dialect or the TensorFlow control
// dialect back into a TensorFlow valid op name.
absl::StatusOr<llvm::StringRef> GetTensorFlowOpName(llvm::StringRef);

// Converts an MLIR operation to TensorFlow NodeDef with given node name. This
// name should be unique to the graph it is being inserted into.

    mlir::Operation* inst, llvm::StringRef name,
    bool ignore_unregistered_attrs) {
  TF_ASSIGN_OR_RETURN(auto node_def, GetOperationNodeDef(inst, name));
  TF_ASSIGN_OR_RETURN(auto op_name,
                      GetTensorFlowOpName(inst->getName().getStringRef()));
  const tensorflow::OpRegistrationData* op_reg_data =
      tensorflow::OpRegistry::Global()->LookUp(op_name.str());
  TF_RETURN_IF_ERROR(GetAttrValuesFromOperation(inst, name, op_reg_data,

    } else if (auto island =
                   llvm::dyn_cast<mlir::tf_executor::IslandOp>(inst)) {
      Operation& inner_op = island.GetBody().front();
      auto op_name = GetTensorFlowOpName(inner_op.getName().getStringRef());
      if (llvm::isa<FuncOp>(inner_op) && op_name.ok()) {
        // If it is TF Control dialect specific op, look up custom operation

    } else if (auto island =
                   llvm::dyn_cast<mlir::tf_executor::IslandOp>(inst)) {
      Operation& inner_op = island.GetBody().front();
      auto op_name = GetTensorFlowOpName(inner_op.getName().getStringRef());
      if (llvm::isa<FuncOp>(inner_op) && op_name.ok()) {
        // If it is TF Control dialect specific op, look up custom operation