refactor

python · eendebakpt · Mar 25, 2026 · Apr 4, 2026 · Apr 4, 2026 · Apr 4, 2026
commit d52937f8e039616353daf85fd41c18ae9f470dda
diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
@@ -4021,6 +4021,31 @@ def testfunc(n):
         self.assertIn("_TO_BOOL_DICT", uops)
         self.assertNotIn("_TO_BOOL", uops)
 
+    def test_guard_type_version_resolves_type_for_to_bool(self):
+        # Tests the _GUARD_TYPE_VERSION + _RECORD_TOS_TYPE flow:
+        # TO_BOOL_GENERIC records the type, then _GUARD_TYPE_VERSION
+        # resolves it (even if the version cache has a collision),
+        # enabling the optimizer to specialize _TO_BOOL → _TO_BOOL_DICT.
+        def testfunc(n):
+            d = {"key": "value"}
+            count = 0
+            for _ in range(n):
+                if d:
+                    count += 1
+                d["key"] = "value"  # mutation keeps dict non-trivial
+            return count
+
+        res, ex = self._run_with_optimizer(testfunc, TIER2_THRESHOLD)
+        self.assertEqual(res, TIER2_THRESHOLD)
+        self.assertIsNotNone(ex)
+        uops = get_opnames(ex)
+        # The optimizer should resolve the dict type from recorded type
+        # info and specialize _TO_BOOL into _TO_BOOL_DICT
+        self.assertIn("_TO_BOOL_DICT", uops)
+        self.assertNotIn("_TO_BOOL", uops)
+        # _GUARD_TYPE_VERSION should be present (guards the dict type)
+        self.assertIn("_GUARD_TYPE_VERSION", uops)
+
     def test_attr_promotion_failure(self):
         # We're not testing for any specific uops here, just
         # testing it doesn't crash.

@@ -557,8 +557,9 @@ dummy_func(
         tier2 pure op(_TO_BOOL_DICT, (value -- res)) {
             PyObject *value_o = PyStackRef_AsPyObjectBorrow(value);
             assert(PyAnyDict_CheckExact(value_o));
-            PyStackRef_CLOSE(value);
+            STAT_INC(TO_BOOL, hit);
             res = ((PyDictObject *)value_o)->ma_used ? PyStackRef_True : PyStackRef_False;
+            PyStackRef_CLOSE(value);
         }
 
         inst(TO_BOOL_NONE, (unused/1, unused/2, value -- res)) {

diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
diff --git a/Python/specialize.c b/Python/specialize.c
@@ -2699,7 +2699,7 @@ to_bool_fail_kind(PyObject *value)
 #endif  // Py_STATS
 
 static int
-check_type_always_succeeds(PyTypeObject *ty)
+check_type_noop(PyTypeObject *ty)
 {
     (void)ty;
     return 0;
@@ -2771,7 +2771,7 @@ _Py_Specialize_ToBool(_PyStackRef value_o, _Py_CODEUNIT *instr)
         unsigned int version;
         if (PyType_HasFeature(tp, Py_TPFLAGS_HEAPTYPE)) {
             version = 0;
-            int err = _PyType_Validate(tp, check_type_always_succeeds, &version);
+            int err = _PyType_Validate(tp, check_type_noop, &version);
             if (err < 0) {
                 SPECIALIZATION_FAIL(TO_BOOL, SPEC_FAIL_OUT_OF_VERSIONS);
                 goto failure;