[dynamo, 3.12] force LOAD_SUPER_ATTR second bit on (pytorch#123686)

This was pretty painful to find haha

Pull Request resolved: pytorch#123686
Approved by: https://github.com/jansel

Author: williamwen42

test/dynamo/test_misc.py

@@ -9951,6 +9951,20 @@ def fn(x):
         opt_fn = torch.compile(fn, backend="eager")
         opt_fn(torch.randn(5, 5))
 
+    def test_super_after_graph_break(self):
+        class Foo(torch.nn.Sequential):
+            def __init__(self, layers):
+                torch._dynamo.graph_break()
+                super().__init__(*layers)
+
+        def fn(x):
+            layers = [torch.nn.Linear(3, 3) for _ in range(3)]
+            mod = Foo(layers)
+            return mod(x)
+
+        opt_fn = torch.compile(fn, backend="eager")
+        opt_fn(torch.randn(3, 3))
+
     def test_raises_importerror1(self):
         @torch.compile(backend="eager")
         def fn(x):

torch/_dynamo/bytecode_transformation.py

@@ -1031,8 +1031,11 @@ def should_compute_arg():
         elif instructions[i].opname == "LOAD_SUPER_ATTR":
             assert instructions[i].arg is not None
             assert instructions[i].argval is not _NotProvided
-            instructions[i].arg = (names[instructions[i].argval] << 2) + (
-                cast(int, instructions[i].arg) % 4
+            # Copy low bit, force second bit on for explicit super (the "+ 2")
+            instructions[i].arg = (
+                (names[instructions[i].argval] << 2)
+                + (cast(int, instructions[i].arg) % 2)
+                + 2
             )
         elif instructions[i].opcode in HAS_LOCAL:
             if should_compute_arg():
@@ -1141,6 +1144,7 @@ def clean_and_assemble_instructions(
         code_options["co_exceptiontable"] = assemble_exception_table(
             compute_exception_table(instructions)
         )
+
     return instructions, types.CodeType(*[code_options[k] for k in keys])
 
 

torch/_dynamo/symbolic_convert.py

@@ -1905,8 +1905,7 @@ def LOAD_FAST_AND_CLEAR(self, inst):
         self.symbolic_locals[inst.argval] = NullVariable()
 
     def LOAD_SUPER_ATTR(self, inst):
-        super_vt, cls_vt, self_vt = self.popn(3)
-        self.call_function(super_vt, [cls_vt, self_vt], {})
+        self.CALL_FUNCTION(dataclasses.replace(inst, argval=2))
         if inst.arg & 1:
             self.LOAD_METHOD(inst)
         else: