diff --git a/src/rewrite_rnn.cpp b/src/rewrite_rnn.cpp
index 308a95d58ee..62532473cb0 100644
--- a/src/rewrite_rnn.cpp
+++ b/src/rewrite_rnn.cpp
@@ -969,10 +969,11 @@ void rewrite_rnn::apply_lstm(module& m, instruction_ref ins) const
 
         // process weight of the peephole
         instruction_ref pph = m.end();
-        // if(args.size() == 8 and not args[7]->is_undefined())
-        // {
-        //     pph = args[7];
-        // }
+        if(args.size() == 8 and not args[7]->is_undefined() and
+           not args[7]->get_shape().lens().empty())
+        {
+            pph = args[7];
+        }
 
         if(not is_forward and variable_seq_len)
         {