Bug fix in testing mode.

paddle/gserver/layers/ConcatenateLayer.cpp

@@ -160,8 +160,10 @@ void ConcatenateLayer2::forward(PassType passType) {
     size_t startCol = projCol_[i].first;
     size_t endCol = projCol_[i].second;
     projOutput_[i].value = output_.value->subColMatrix(startCol, endCol);
+    if (output_.grad) {
       projOutput_[i].grad = output_.grad->subColMatrix(startCol, endCol);
     }
+  }
 
   {
     AsyncGpuBlock block;

paddle/gserver/layers/SpatialPyramidPoolLayer.cpp

@@ -112,8 +112,10 @@ void SpatialPyramidPoolLayer::forward(PassType passType) {
     size_t startCol = projCol_[i].first;
     size_t endCol = projCol_[i].second;
     projOutput_[i].value = output_.value->subColMatrix(startCol, endCol);
+    if (output_.grad) {
       projOutput_[i].grad = output_.grad->subColMatrix(startCol, endCol);
     }
+  }
   for (size_t i = 0; i < pyramidHeight_; i++) {
     poolProjections_[i]->forward(&getInput(0), &projOutput_[i], passType);
   }