message: Check empty rather than computing full vector size.
diff: @@ -287,7 +287,7 @@ Operation* ReplicateControlFlowStack(
  const llvm::SmallVectorImpl<ControlFlowStackInfo>& stack_info,
  tf_device::ClusterOp tpu_cluster, ModuleOp module, Value compilation_key,
  Block* destination_block, int* send_recv_counter) {
  - assert(stack_info.size());
  + assert(!stack_info.empty());
  OpBuilder builder = OpBuilder::atBlockTerminator(destination_block);
  Operation* previous_replicated_controlflow_op = nullptr;
  for (const auto& controlflow_stack_info : stack_info) {
  