Merge 3.5
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 40da0b1..5f22455 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -4495,11 +4495,13 @@
simple:
assert(Py_REFCNT(a) > 0);
assert(Py_REFCNT(b) > 0);
-#if LONG_MAX >> 2*PyLong_SHIFT
+/* Issue #24999: use two shifts instead of ">> 2*PyLong_SHIFT" to avoid
+ undefined behaviour when LONG_MAX type is smaller than 60 bits */
+#if LONG_MAX >> PyLong_SHIFT >> PyLong_SHIFT
/* a fits into a long, so b must too */
x = PyLong_AsLong((PyObject *)a);
y = PyLong_AsLong((PyObject *)b);
-#elif defined(PY_LONG_LONG) && PY_LLONG_MAX >> 2*PyLong_SHIFT
+#elif defined(PY_LONG_LONG) && PY_LLONG_MAX >> PyLong_SHIFT >> PyLong_SHIFT
x = PyLong_AsLongLong((PyObject *)a);
y = PyLong_AsLongLong((PyObject *)b);
#else
@@ -4516,9 +4518,9 @@
y = x % y;
x = t;
}
-#if LONG_MAX >> 2*PyLong_SHIFT
+#if LONG_MAX >> PyLong_SHIFT >> PyLong_SHIFT
return PyLong_FromLong(x);
-#elif defined(PY_LONG_LONG) && PY_LLONG_MAX >> 2*PyLong_SHIFT
+#elif defined(PY_LONG_LONG) && PY_LLONG_MAX >> PyLong_SHIFT >> PyLong_SHIFT
return PyLong_FromLongLong(x);
#else
# error "_PyLong_GCD"