[dynamo] graph break on issubclass call with non-const args (#125943)

Fixes #125942

Pull Request resolved: #125943
Approved by: https://github.com/jansel
ghstack dependencies: #125882

test/dynamo/test_repros.py

@@ -4962,6 +4962,15 @@ def fn(x):
         inp = torch.randn(3, 3)
         self.assertEqual(fn(inp), opt_fn(inp))
 
+    def test_nonconst_issubclass(self):
+        def fn(x):
+            if issubclass(x.__class__, np.ndarray):
+                return 1
+            return 0
+
+        opt_fn = torch.compile(fn, backend="eager")
+        opt_fn(np.ones([3, 3]))
+
 
 instantiate_parametrized_tests(ReproTests)
 

torch/_dynamo/variables/builtin.py

@@ -1402,10 +1402,15 @@ def check_type(ty):
 
     def call_issubclass(self, tx, left_ty, right_ty):
         """Checks if first arg is subclass of right arg"""
-        left_ty = left_ty.as_python_constant()
-        right_ty = right_ty.as_python_constant()
+        try:
+            left_ty_py = left_ty.as_python_constant()
+            right_ty_py = right_ty.as_python_constant()
+        except NotImplementedError:
+            unimplemented(
+                f"call_issubclass args not constant left_ty: {left_ty}, right_ty: {right_ty}"
+            )
 
-        return variables.ConstantVariable(issubclass(left_ty, right_ty))
+        return variables.ConstantVariable(issubclass(left_ty_py, right_ty_py))
 
     def call_super(self, tx, a, b):
         return variables.SuperVariable(a, b)