[dynamo] Add support for DELETE_SUBSCR (pytorch#123526)

Fixes pytorch#123317

Co-authored-by: Jason Ansel <jansel@meta.com>
Pull Request resolved: pytorch#123526
Approved by: https://github.com/jansel

Author: arunppsg

test/dynamo/test_repros.py

@@ -3300,6 +3300,29 @@ def fn(x, obj):
         obj1 = MyObj(x, x)
         self.assertRaises(AttributeError, lambda: fn(x, obj1))
 
+    def test_delsubscr(self):
+        @torch.compile(backend="eager")
+        def fn(x):
+            del x["a"]
+            y = x["b"] + 1
+            return y
+
+        x = {"a": torch.tensor([1]), "b": torch.tensor([1])}
+        result = fn(x)
+        self.assertFalse(hasattr(x, "a"))
+        self.assertEqual(result.item(), 2)
+
+    def test_delsubscr_raises(self):
+        @torch.compile(backend="eager")
+        def fn(x):
+            del x["a"]
+            y = x["a"] + 1  # should raise KeyError
+            return y
+
+        x = {"a": torch.tensor([1]), "b": torch.tensor([1])}
+        # FIXME It should be KeyError here
+        self.assertRaises(torch._dynamo.exc.InternalTorchDynamoError, lambda: fn(x))
+
     def test_attached_attribute_in_dir(self):
         class MyModule(torch.nn.Module):
             def __init__(self):

test/dynamo_expected_failures/TestAOTModuleSimplified.test_aot_module_simplified_fake_tensor_gm_raises

@@ -1420,6 +1420,10 @@ def STORE_SUBSCR(self, inst):
         val, obj, key = self.popn(3)
         result = obj.call_method(self, "__setitem__", [key, val], {})
 
+    def DELETE_SUBSCR(self, inst):
+        obj, key = self.popn(2)
+        obj.call_method(self, "__delitem__", [key], {})
+
     def BUILD_TUPLE(self, inst):
         items = self.popn(inst.argval)
         self.push(TupleVariable(items))

test/dynamo_expected_failures/TestReductionsCPU.test_std_vs_numpy_cpu_complex128

@@ -249,6 +249,10 @@ def call_method(
             tx.output.side_effects.mutation(self)
             self.items[Hashable(args[0])] = args[1]
             return ConstantVariable.create(None)
+        elif name == "__delitem__" and arg_hashable and self.mutable_local:
+            tx.output.side_effects.mutation(self)
+            self.items.__delitem__(Hashable(args[0]))
+            return ConstantVariable.create(None)
         elif name in ("pop", "get") and len(args) in (1, 2) and args[0] not in self:
             # missing item, return the default value
             if len(args) == 1:
@@ -889,18 +893,13 @@ def reconstruct(self, codegen):
     def call_method(
         self, tx, name, args: List[VariableTracker], kwargs: Dict[str, VariableTracker]
     ):
-        from .builder import VariableBuilder
-
         if name == "__getitem__":
             return self.call_getitem(tx, *args, **kwargs)
         elif name == "get":
             return self.call_get(tx, *args, **kwargs)
         elif name == "__contains__":
             return self.call_contains(tx, *args, **kwargs)
-
-        # Fallback to dict implementation
-        real_dict = VariableBuilder(tx, self.source)(sys.modules)
-        return real_dict.call_method(tx, name, args, kwargs)
+        unimplemented(f"sys.modules.{name}(*{args}, **{kwargs})")
 
     def _contains_helper(self, tx, key: VariableTracker):
         k = key.as_python_constant()