Polish code

test=develop

paddle/fluid/operators/math/selected_rows_functor.cu

@@ -275,7 +275,8 @@ struct MergeAdd<platform::CUDADeviceContext, T> {
 
   void operator()(const platform::CUDADeviceContext& context,
                   const framework::SelectedRows& input,
-                  framework::SelectedRows* output) {
+                  framework::SelectedRows* output,
+                  const bool sorted_result = false) {
     framework::Vector<int64_t> input_rows(input.rows());
     if (input_rows.size() == 0) {
       return;
@@ -313,7 +314,8 @@ struct MergeAdd<platform::CUDADeviceContext, T> {
 
   void operator()(const platform::CUDADeviceContext& context,
                   const std::vector<const framework::SelectedRows*>& inputs,
-                  framework::SelectedRows* output) {
+                  framework::SelectedRows* output,
+                  const bool sorted_result = false) {
     if (inputs.size() == 0) {
       VLOG(3) << "no input! return";
       return;