Remove input_format in backward.cc

paddle/framework/backward.cc

@@ -127,11 +127,8 @@ std::shared_ptr<OperatorBase> BackwardRecursive(
         net->ops_[op_offset]->Rename(name, dup_outputs.back());
       }
       insert_position.push_back(
-          {dup_op.back(),
+          {dup_op.back(), OpRegistry::CreateOp("add", {{"X", {dup_outputs}}},
-           OpRegistry::CreateOp(
+                                               {{"Out", {name}}}, {})});
-               "add", {{"X", {dup_outputs}}}, {{"Out", {name}}},
-               {{"input_format",
-                 std::vector<int>{0, static_cast<int>(dup_outputs.size())}}})});
     }
 
     insert_position.sort(
@@ -140,7 +137,6 @@ std::shared_ptr<OperatorBase> BackwardRecursive(
     for (auto& pos : insert_position) {
       net->InsertOp(pos.first + 1, pos.second);
     }
-
   } else {
     std::shared_ptr<OperatorBase> grad_op = OpRegistry::CreateGradOp(forwardOp);
 
@@ -176,7 +172,7 @@ std::shared_ptr<OperatorBase> BackwardRecursive(
   net->type_ = "@GENERATED_BACKWARD@";
   net->CompleteAddOp();
   return net;
-}
+}  // namespace framework
 
 // See header for comments
 std::shared_ptr<OperatorBase> Backward(