handle probable and non-probable cases

python · Fidget-Spinner · Apr 12, 2026 · Apr 12, 2026 · Apr 12, 2026 · Apr 12, 2026
commit 13e2608def0f8385d5056fce8bb6c7c0f301e638
@@ -1071,40 +1071,39 @@ dummy_func(void) {
     op(_CHECK_OBJECT, (type_version/2, callable, self_or_null, unused[oparg] -- callable, self_or_null, unused[oparg])) {
         PyObject *probable_callable = sym_get_probable_value(callable);
         assert(probable_callable != NULL);
-        PyTypeObject *tp = (PyTypeObject *)probable_callable;
-        if (tp->tp_version_tag == type_version) {
-            // If the type version has not changed since we last saw it,
-            // then we know this __init__ is definitely the same one as in the cache.
-            // We can promote callable to a known constant. This does not need a
-            // type watcher, as we do not remove this _CHECK_AND_ALLOCATE_OBJECT guard.
-            if (sym_is_null(self_or_null) && sym_matches_type(callable, &PyType_Type)) {
+        PyObject *const_callable = sym_get_const(ctx, callable);
+        bool is_probable = const_callable == NULL && probable_callable != NULL;
+        PyObject *callable_o = const_callable != NULL ? const_callable : probable_callable;
+        if (sym_is_null(self_or_null) &&
+            callable_o != NULL &&
+            PyType_Check(callable_o) &&
+            ((PyTypeObject *)callable_o)->tp_version_tag == type_version) {
+            // Probable types need the guard.
+            if (!is_probable) {
                 ADD_OP(_NOP, 0, 0);
             }
-            PyHeapTypeObject *cls = (PyHeapTypeObject *)probable_callable;
+            else {
+                // Promote the probable type, as we have
+                // guarded on it.
+                sym_set_const(callable, callable_o);
+            }
+            PyHeapTypeObject *cls = (PyHeapTypeObject *)callable_o;
             PyObject *init = cls->_spec_cache.init;
             assert(init != NULL);
             assert(PyFunction_Check(init));
-            sym_set_const(callable, init);
+            callable = sym_new_const(ctx, init);
+            PyType_Watch(TYPE_WATCHER_ID, callable_o);
+            _Py_BloomFilter_Add(dependencies, callable_o);;
         }
         else {
-            // add watcher so that whenever the type changes we invalidate this
-            PyTypeObject *type = _PyType_LookupByVersion(type_version);
-            // if the type is null, it was not found in the cache (there was a conflict)
-            // with the key, in which case we can't trust the version
-            if (type) {
-                // if the type version was set properly, then add a watcher
-                // if it wasn't this means that the type version was previously set to something else
-                // and we set the callable to bottom, so we don't need to add a watcher because we must have
-                // already added one earlier.
-                if (sym_set_type_version(callable, type_version)) {
-                    PyType_Watch(TYPE_WATCHER_ID, (PyObject *)type);
-                    _Py_BloomFilter_Add(dependencies, type);
-                }
-            }
-       self_or_null = sym_new_not_null(ctx);
+            callable = sym_new_not_null(ctx);
         }
     }
 
+    op(_ALLOCATE_OBJECT, (callable, self_or_null, unused[oparg] -- callable, self_or_null, unused[oparg])) {
+        self_or_null = sym_new_not_null(ctx);
+    }
+
     op(_CREATE_INIT_FRAME, (init, self, args[oparg] -- init_frame)) {
         ctx->frame->stack_pointer = stack_pointer - oparg - 2;
         _Py_UOpsAbstractFrame *shim = frame_new(ctx, (PyCodeObject *)&_Py_InitCleanup, NULL, 0);

diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h