need to copy LoD info (#10392)

paddle/fluid/operators/save_op.cc

@@ -106,6 +106,8 @@ class SaveOp : public framework::OperatorBase {
       auto out_kernel_type = framework::OpKernelType(out_dtype, place);
       framework::LoDTensor out;
       framework::TransDataType(in_kernel_type, out_kernel_type, tensor, &out);
+      // copy LoD info to the new tensor
+      out.set_lod(tensor.lod());
       framework::SerializeToStream(fout, out, dev_ctx);
     } else {
       framework::SerializeToStream(fout, tensor, dev_ctx);