add eos layer as an extra parent.

python/paddle/v2/layer.py

@@ -132,6 +132,13 @@ def __get_used_layers__(output_layers):
                     add_parent(mem.layer_name, mem.boot_layer_name)
                 add_parent(mem.link_name, mem.layer_name)
 
+            if sub_model.HasField('generator'):
+                # according to the implementation of text generation
+                # in recurrent layer group, the generated word must be
+                # the first out link
+                add_parent(sub_model.out_links[0].layer_name,
+                           sub_model.generator.eos_layer_name)
+
     def dfs_travel(layer_name):
         if layer_name in layer_names:
             return
@@ -175,8 +182,6 @@ def __get_used_submodels__(layer_names):
     for submodel in cp.g_config.model_config.sub_models:
         if submodel.name in layer_names:
             submodel_names.add(submodel.name)
-            if submodel.is_recurrent_layer_group:
-                layer_names |= set(submodel.layer_names)
     return submodel_names