gh-134584: Eliminate redundant refcounting from _STORE_ATTR_WITH_HINT

Lib/test/test_capi/test_opt.py

@@ -2593,6 +2593,26 @@ class C:
         self.assertNotIn("_POP_TOP", uops)
         self.assertIn("_POP_TOP_NOP", uops)
 
+    def test_store_attr_with_hint(self):
+        def testfunc(n):
+            class C:
+                pass
+            c = C()
+            for i in range(_testinternalcapi.SHARED_KEYS_MAX_SIZE - 1):
+                setattr(c, f"_{i}", None)
+
+            for i in range(n):
+                c.x = i
+            return c.x
+        res, ex = self._run_with_optimizer(testfunc, TIER2_THRESHOLD)
+        self.assertEqual(res, TIER2_THRESHOLD - 1)
+        self.assertIsNotNone(ex)
+        uops = get_opnames(ex)
+
+        self.assertIn("_STORE_ATTR_WITH_HINT", uops)
+        self.assertNotIn("_POP_TOP", uops)
+        self.assertIn("_POP_TOP_NOP", uops)
+
     def test_store_subscr_int(self):
         def testfunc(n):
             l = [0, 0, 0, 0]

Misc/NEWS.d/next/Core_and_Builtins/2025-12-16-05-24-24.gh-issue-134584.tJ1usH.rst

@@ -0,0 +1 @@
+Eliminate redundant refcounting from ``_STORE_ATTR_WITH_HINT``.

Python/bytecodes.c

@@ -2601,7 +2601,7 @@ dummy_func(
             _STORE_ATTR_INSTANCE_VALUE +
             POP_TOP;
 
-        op(_STORE_ATTR_WITH_HINT, (hint/1, value, owner --)) {
+        op(_STORE_ATTR_WITH_HINT, (hint/1, value, owner -- o)) {
             PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
             assert(Py_TYPE(owner_o)->tp_flags & Py_TPFLAGS_MANAGED_DICT);
             PyDictObject *dict = _PyObject_GetManagedDict(owner_o);
@@ -2631,14 +2631,16 @@ dummy_func(
             // old_value should be DECREFed after GC track checking is done, if not, it could raise a segmentation fault,
             // when dict only holds the strong reference to value in ep->me_value.
             STAT_INC(STORE_ATTR, hit);
-            PyStackRef_CLOSE(owner);
+            o = owner;
+            DEAD(owner);
             Py_XDECREF(old_value);
         }
 
         macro(STORE_ATTR_WITH_HINT) =
             unused/1 +
             _GUARD_TYPE_VERSION +
-            _STORE_ATTR_WITH_HINT;
+            _STORE_ATTR_WITH_HINT +
+            POP_TOP;
 
         op(_STORE_ATTR_SLOT, (index/1, value, owner -- o)) {
             PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);

Python/optimizer_bytecodes.c

@@ -104,6 +104,11 @@ dummy_func(void) {
         o = owner;
     }
 
+    op(_STORE_ATTR_WITH_HINT, (hint/1, value, owner -- o)) {
+        (void)value;
+        o = owner;
+    }
+
     op(_STORE_FAST, (value --)) {
         GETLOCAL(oparg) = value;
     }