fixes 'misaligned address' when using 'group' parameter in CNN layers…

…. This fixes the error by aligning by the address to be multiple of m (32). Fixes also another bug of not correctly grouped if..else

see: BVLC#5729

src/caffe/layers/cudnn_conv_layer.cpp

@@ -186,6 +186,8 @@ void CuDNNConvolutionLayer<Dtype>::Reshape(
                              total_workspace_bwd_data);
   max_workspace = std::max(max_workspace, total_workspace_bwd_filter);
   // ensure all groups have enough workspace
+  size_t m=32;
+  max_workspace = (max_workspace + m-1) / m * m; //align address to be multiples of m
   size_t total_max_workspace = max_workspace *
                                (this->group_ * CUDNN_STREAMS_PER_GROUP);
 
@@ -217,10 +219,11 @@ void CuDNNConvolutionLayer<Dtype>::Reshape(
       workspaceData = NULL;
       workspaceSizeInBytes = 0;
     }
-
-    // if we succeed in the allocation, set pointer aliases for workspaces
-    for (int g = 0; g < (this->group_ * CUDNN_STREAMS_PER_GROUP); g++) {
-      workspace[g] = reinterpret_cast<char *>(workspaceData) + g*max_workspace;
+    else {
+      // if we succeed in the allocation, set pointer aliases for workspaces
+      for (int g = 0; g < (this->group_ * CUDNN_STREAMS_PER_GROUP); g++) {
+        workspace[g] = reinterpret_cast<char *>(workspaceData) + g*max_workspace;
+      }
     }
   }