Update

paddle/framework/grad_op_builder.cc

@@ -76,7 +76,7 @@ static void TransOpArg(const OperatorBase* src_op, OperatorBase* dst_op,
 }
 
 OperatorBase* BuildGradOp(const OperatorBase* op) {
-  std::string grad_op_type = OpRegistry::grad_ops().at(op->type_);
+  const std::string& grad_op_type = OpRegistry::grad_ops().at(op->Type());
   OperatorBase* grad_op = OpRegistry::op_creators().at(grad_op_type)();
   grad_op->type_ = grad_op_type;
   grad_op->attrs_ = op->attrs_;