[TF Led] Fix wrong decoder attention mask behavior (#9601)

* fix tf led

* remove loop file

src/transformers/models/led/modeling_tf_led.py

@@ -1862,7 +1862,6 @@ class TFLEDDecoder(tf.keras.layers.Layer):
         hidden_states = inputs["inputs_embeds"]
 
         # [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len]
-        combined_attention_mask = None
         if input_shape[-1] > 1:
             combined_attention_mask = _make_causal_mask(input_shape, past_key_values_length=past_key_values_length)
         else:
@@ -1870,20 +1869,9 @@ class TFLEDDecoder(tf.keras.layers.Layer):
                 tf.ones((input_shape[0], input_shape[1] + past_key_values_length)), tgt_len=input_shape[-1]
             )
 
-        if inputs["attention_mask"] is None and inputs["input_ids"] is not None and input_shape[-1] > 1:
-            inputs["attention_mask"] = tf.cast(
-                tf.math.not_equal(inputs["input_ids"], self.config.pad_token_id), inputs["input_ids"].dtype
-            )
-            inputs["attention_mask"] = tf.concat(
-                [
-                    tf.ones((input_shape[0], past_key_values_length), dtype=inputs["attention_mask"].dtype),
-                    inputs["attention_mask"],
-                ],
-                axis=-1,
-            )
-        else:
-            inputs["attention_mask"] = tf.ones(
-                (input_shape[0], input_shape[1] + past_key_values_length), dtype=tf.int32
+        if inputs["attention_mask"] is not None and input_shape[-1] > 1:
+            combined_attention_mask = combined_attention_mask + _expand_mask(
+                inputs["attention_mask"], tgt_len=input_shape[-1]
             )
 
         if inputs["encoder_hidden_states"] is not None and inputs["encoder_attention_mask"] is not None: