[Dynamo] Add debug linting option for graph dedupe (#150053)

As title

Pull Request resolved: https://github.com/pytorch/pytorch/pull/150053
Approved by: https://github.com/StrongerXi, https://github.com/anijain2305

torch/_dynamo/config.py

@@ -432,6 +432,10 @@ use_graph_deduplication = False
 # This flag is ignored if use_graph_deduplication is True
 track_nodes_for_deduplication = False
 
+# Whether to lint the graph after each region is replaced
+# (Debug)
+graph_deduplication_lint = False
+
 # Issues a warning in Python 3.13.0 for possibly slower guard evaluation and
 # instructs user to attempt using 3.13.1+, where the CPython bug is fixed.
 # Should be disabled in dynamo-wrapped tests since some tests check that no warnings are issued.

torch/_dynamo/graph_deduplication.py

@@ -13,6 +13,7 @@ from collections.abc import Iterable
 from typing import Any
 
 import torch.fx
+from torch._dynamo import config
 from torch._higher_order_ops.utils import has_potential_input_alias_or_mutation
 from torch.utils._pytree import tree_flatten
 
@@ -154,6 +155,9 @@ def _replace_region_with_subgraph(
         for node in reversed(region):
             graph.erase_node(node)
 
+    if config.graph_deduplication_lint:
+        graph.lint()
+
 
 def _get_external_inputs(
     region: Region,