From da2bacd53e27e61185ea53d4df7c6ada68651d14 Mon Sep 17 00:00:00 2001
From: Yanbo Liang <ybliang@fb.com>
Date: Mon, 9 May 2022 15:29:09 -0700
Subject: [PATCH 1/2] Correct ListVariable source

---
 tests/test_misc.py             | 12 ++++++++++++
 torchdynamo/utils.py           |  2 +-
 torchdynamo/variables/lists.py |  9 ++++++---
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/tests/test_misc.py b/tests/test_misc.py
index ee00084da0..aec57857f2 100755
--- a/tests/test_misc.py
+++ b/tests/test_misc.py
@@ -1157,3 +1157,15 @@ def fn():
         inst = dis.get_instructions(fn)
         result = bytecode_transformation.assemble(inst, fn.__code__.co_firstlineno)
         self.assertTrue(result[1] == fn.__code__.co_lnotab)
+
+    def test_python_slice(self):
+        def fn(input):
+            y = 0
+            for i, x in enumerate(input[2:], 1):
+                y = y + x
+            return y
+
+        cnts = torchdynamo.testing.CompileCounter()
+        with torchdynamo.optimize(cnts):
+            z = fn([1, 2, 3, 5])
+        self.assertEqual(z, 8)
diff --git a/torchdynamo/utils.py b/torchdynamo/utils.py
index 38763f953a..3fe52239a7 100644
--- a/torchdynamo/utils.py
+++ b/torchdynamo/utils.py
@@ -319,7 +319,7 @@ def rot_n_helper(n):
 def is_safe_constant(v):
     if istype(v, (tuple, frozenset)):
         return all(map(is_safe_constant, v))
-    return istype(v, (types.CodeType, int, float, bool, str, bytes, type(None)))
+    return istype(v, (types.CodeType, int, float, bool, str, bytes, type(None), slice))
 
 
 def check_constant_args(args, kwargs):
diff --git a/torchdynamo/variables/lists.py b/torchdynamo/variables/lists.py
index b0892aeb05..5d9cc80bc2 100644
--- a/torchdynamo/variables/lists.py
+++ b/torchdynamo/variables/lists.py
@@ -9,6 +9,7 @@
 from ..utils import namedtuple_fields
 from .base import MutableLocal
 from .base import VariableTracker
+from ..source import GetItemSource
 
 
 class BaseListVariable(VariableTracker):
@@ -40,9 +41,11 @@ def as_proxy(self):
     def getitem_const(self, arg: VariableTracker):
         index = arg.as_python_constant()
         if isinstance(index, slice):
-            return self.clone(items=self.items[index], mutable_local=None).add_options(
-                arg, self
-            )
+            return self.clone(
+                items=self.items[index],
+                source=GetItemSource(self.source, index),
+                mutable_local=None,
+            ).add_options(arg, self)
         else:
             assert isinstance(index, int)
             return self.items[index].add_options(arg, self)

From 374c27d1c8770055cf8cea4ccb56cca91fc10d54 Mon Sep 17 00:00:00 2001
From: Yanbo Liang <ybliang@fb.com>
Date: Mon, 9 May 2022 16:15:39 -0700
Subject: [PATCH 2/2] Fix lint

---
 torchdynamo/variables/lists.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/torchdynamo/variables/lists.py b/torchdynamo/variables/lists.py
index 5d9cc80bc2..3c4c79c7a7 100644
--- a/torchdynamo/variables/lists.py
+++ b/torchdynamo/variables/lists.py
@@ -6,10 +6,10 @@
 from .. import variables
 from ..bytecode_transformation import create_instruction
 from ..exc import unimplemented
+from ..source import GetItemSource
 from ..utils import namedtuple_fields
 from .base import MutableLocal
 from .base import VariableTracker
-from ..source import GetItemSource
 
 
 class BaseListVariable(VariableTracker):