exclude mutated buffer

Differential Revision: D55812844

Author: cccclai

exir/backend/utils.py

@@ -515,6 +515,12 @@ def tag_constant_data(edge_program: ExportedProgram) -> None:
             or is_buffer(edge_program, node)
             or is_lifted_tensor_constant(edge_program, node)
         ):
+            for node_user in node.users:
+                if node_user.name in edge_program.graph_signature.buffers_to_mutate:
+                    logging.info(
+                        "The buffer node is a mutated buffer node, which is not constant."
+                    )
+                    continue
             user_tags = set()
             for user in node.users:
                 user_tag = user.meta.get("delegation_tag", None)