[dynamo] Fix side effects for range iterator that escapes the graph (pytorch#141716)

`wrap_range_iterator` mistakenly used `ValueMutationNew`, when it
should've used `ValueMutationExisting`, because this code path always
has a source.

Pull Request resolved: pytorch#141716
Approved by: https://github.com/jansel
ghstack dependencies: pytorch#141713, pytorch#141714, pytorch#141715, pytorch#141902

Author: StrongerXi

test/dynamo/test_misc.py

@@ -1800,6 +1800,17 @@ def run(n):
         self.assertTrue(same(res2, torch.ones(2)))
         self.assertTrue(same(res3, torch.ones(3)))
 
+    def test_range_iter_side_effects(self):
+        @torch.compile(backend="eager", fullgraph=True)
+        def run(x, it):
+            n = next(it)
+            return x + n
+
+        it = iter(range(1, 3))
+        res = run(torch.zeros(1), it)
+        self.assertTrue(same(res, torch.ones(1)))
+        self.assertEqual(next(it), 2)
+
     def test_build_tuple_unpack(self):
         def fn1(a, b, c):
             return a - b / c

torch/_dynamo/side_effects.py

@@ -748,7 +748,7 @@ def codegen_update_mutated(self, cg: PyCodegen):
                         cg(value)
                         cg(var.source)
                         suffixes.append([create_instruction("STORE_ATTR", argval=name)])
-            elif isinstance(var, variables.TupleIteratorVariable):
+            elif isinstance(var, variables.ListIteratorVariable):
                 for _ in range(var.index):
                     cg.add_push_null(
                         lambda: cg.load_import_from(utils.__name__, "iter_next")

torch/_dynamo/variables/builder.py

@@ -1350,7 +1350,8 @@ def wrap_range_iterator(self, value: range_iterator):
         # Get all the values from the range iterator; no need to install guards
         # on items since `RANGE_ITERATOR_MATCH` guarantees the same items.
         items = [ConstantVariable.create(v) for v in copy.deepcopy(value)]
-        return ListIteratorVariable(items, mutation_type=ValueMutationNew())
+        result = ListIteratorVariable(items, source=self.source)
+        return self.tx.output.side_effects.track_mutable(value, result)
 
     def wrap_slice_range(self, value: Union[slice, range]):
         items = [