bug fix when all inputs are empty

paddle/fluid/operators/sum_mkldnn_op.cc

@@ -187,6 +187,9 @@ class SumMKLDNNOpKernel : public paddle::framework::OpKernel<T> {
 
       if (in_dim.empty()) {
         VLOG(3) << "WARNING: all the inputs are empty";
+        in_dim = framework::vectorize(get_selected_row(N - 1).value().dims());
+      } else {
+        in_dim[0] = static_cast<int64_t>(first_dim);
       }
 
       in_dim[0] = static_cast<int64_t>(first_dim);

paddle/fluid/operators/sum_op.h

@@ -116,10 +116,11 @@ class SumKernel : public framework::OpKernel<T> {
       }
       if (in_dim.empty()) {
         VLOG(3) << "WARNING: all the inputs are empty";
+        in_dim = framework::vectorize(get_selected_row(N - 1).value().dims());
+      } else {
+        in_dim[0] = static_cast<int64_t>(first_dim);
       }
 
-      in_dim[0] = static_cast<int64_t>(first_dim);
-
       out_value->Resize(framework::make_ddim(in_dim));
       out_value->mutable_data<T>(context.GetPlace());