bool IsSupportedNonTFOp(Operation* op) {
  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,

  // and a return operation to return the Graph results.
  builder_.setInsertionPointToEnd(&graph_op.getBody().front());
  builder_.create<mlir::tf_executor::FetchOp>(graph_op.getLoc(),
                                              inst_to_return);
  builder_.setInsertionPointToEnd(bb);
  builder_.create<mlir::func::ReturnOp>(mlir::UnknownLoc::get(context_),