[Minor fix] (#93)

- Add TODO to remove the source_fn_stack
- Fix the comment of fold_qdq pass
- Remove redundant ops in annotate_quant_attrs

Author: Tsai, Chun-I (Joey)

backends/qualcomm/passes/annotate_quant_attrs.py

@@ -33,8 +33,6 @@ class AnnotateQuantAttrs(ExportPass):
     """
 
     q_ops = {
-        torch.ops.quantized_decomposed.quantize_per_channel.default,
-        torch.ops.quantized_decomposed.quantize_per_tensor.default,
         exir_ops.edge.quantized_decomposed.quantize_per_channel.default,
         exir_ops.edge.quantized_decomposed.quantize_per_tensor.default,
         exir_ops.edge.quantized_decomposed.quantize_per_tensor.tensor,

backends/qualcomm/passes/fold_qdq.py

@@ -11,7 +11,7 @@
 
 class FoldQDQ(ExportPass):
     """
-    Erase QDQ pattern and store encodings into corresponding graph nodes.
+    Erase QDQ pattern.
     """
 
     q_ops = {
@@ -45,6 +45,7 @@ def _fold(self, graph_module: torch.fx.GraphModule) -> torch.fx.GraphModule:
             to_be_removed = [n]
             source_n = n.args[0]
 
+            # TODO: remove this hack as source_fn_stack is internal implementation detail of torch.export.
             # To make constant value/tensor be tagged as delegatable during partition
             if source_n.op == "get_attr":
                 source_n.meta["source_fn_stack"] = list(n.users.keys())[0].meta.get(