gh-127119: Remove check on small ints in long_dealloc

Misc/NEWS.d/next/Core_and_Builtins/2024-11-22-07-58-00.gh-issue-127119.p9Yv4U.rst

@@ -0,0 +1 @@
+Slightly optimize the :class:`int` deallocator by removing a redundant check.

Objects/longobject.c

@@ -3611,24 +3611,28 @@ long_richcompare(PyObject *self, PyObject *other, int op)
     Py_RETURN_RICHCOMPARE(result, 0, op);
 }
 
-static void
-long_dealloc(PyObject *self)
+#ifndef NDEBUG
+static int _is_python_smallint(PyObject *op)
 {
-    /* This should never get called, but we also don't want to SEGV if
-     * we accidentally decref small Ints out of existence. Instead,
-     * since small Ints are immortal, re-set the reference count.
-     */
-    PyLongObject *pylong = (PyLongObject*)self;
+    PyLongObject *pylong = (PyLongObject*)op;
     if (pylong && _PyLong_IsCompact(pylong)) {
         stwodigits ival = medium_value(pylong);
         if (IS_SMALL_INT(ival)) {
             PyLongObject *small_pylong = (PyLongObject *)get_small_int((sdigit)ival);
             if (pylong == small_pylong) {
-                _Py_SetImmortal(self);
-                return;
+                return 1;
             }
         }
     }
+    return 0;
+}
+#endif
+
+static void
+long_dealloc(PyObject *self)
+{
+    // assert the small ints are not deallocated
+    assert(!_is_python_smallint(self));
     Py_TYPE(self)->tp_free(self);
 }