diff --git a/chunk_codegen.py b/chunk_codegen.py
index 47cda0f8e..6740cd44a 100644
--- a/chunk_codegen.py
+++ b/chunk_codegen.py
@@ -827,7 +827,7 @@ def _find_input_and_output_nodes(nodes: List[Node]):
     for node in nodes:
         for input_node in node._input_nodes.keys():
             node_repr = repr(input_node)
-            if input_node not in nodes and node_repr not in input_nodes:
+            if input_node not in nodes and input_node not in input_nodes:
                 input_nodes.append(input_node)
 
     # if a node has a user node which is not in the node list
@@ -835,7 +835,7 @@ def _find_input_and_output_nodes(nodes: List[Node]):
     for node in nodes:
         for output_node in node.users.keys():
             node_repr = repr(node)
-            if output_node not in nodes and node_repr not in output_nodes:
+            if output_node not in nodes and output_node not in output_nodes:
                 output_nodes.append(output_node)
 
     return input_nodes, output_nodes
@@ -848,6 +848,16 @@ def _find_idx_by_name(name, nodes_list):
     raise RuntimeError("name %s not found in node list" % name)
 
 
+def _replace_name(context, name_from, name_to):
+    patterns = [(" ", " "), (" ", "."), (" ", ","), ("(", ")"), ("(", ",")]
+    for p in patterns:
+        source = p[0] + name_from + p[1]
+        target = p[0] + name_to + p[1]
+        if source in context:
+            context = context.replace(source, target)
+    return context
+
+
 def emit_code_with_chunk(body, ckpt_func, nodes, emit_node_func, delete_unused_value_func, meta_nodes, meta_graph):
     """Emit code with nested activation checkpoint
     When we detect some of the node.activation_checkpoint is a List, we will use
@@ -905,8 +915,7 @@ def emit_code_with_chunk(body, ckpt_func, nodes, emit_node_func, delete_unused_v
         if within_chunk_region:
             emit_node_func(node, body)
             # replace input var with chunk var
-            if node_idx in chunk_starts:
-                body[-1] = body[-1].replace(chunk_inputs[region_idx][0].name, 'chunk_tensor')
+            body[-1] = _replace_name(body[-1], chunk_inputs[region_idx][0].name, 'chunk_tensor')
             body[-1] = '    ' + body[-1]
             delete_unused_value_func(node, body, chunk_inputs_names)