diff -r 19488e23dcdb Objects/longobject.c
--- a/Objects/longobject.c	Fri Jun 03 10:48:43 2016 +0300
+++ b/Objects/longobject.c	Fri Jun 03 23:48:25 2016 +0300
@@ -4152,17 +4152,17 @@
     /* Implement ~x as -(x+1) */
     PyLongObject *x;
     PyLongObject *w;
-    if (Py_ABS(Py_SIZE(v)) <=1)
-        return PyLong_FromLong(-(MEDIUM_VALUE(v)+1));
+    if (Py_ABS(Py_SIZE(v)) <= 1)
+        return PyLong_FromLong(-(MEDIUM_VALUE(v) + 1));
     w = (PyLongObject *)PyLong_FromLong(1L);
     if (w == NULL)
         return NULL;
-    x = (PyLongObject *) long_add(v, w);
+    x = (PyLongObject *)long_add(v, w);
     Py_DECREF(w);
     if (x == NULL)
         return NULL;
-    Py_SIZE(x) = -(Py_SIZE(x));
-    return (PyObject *)maybe_small_long(x);
+    _PyLong_Negate(&x);
+    return (PyObject *)x;
 }
 
 static PyObject *