diff -r 62438d1b11c7 Lib/test/test_long.py
--- a/Lib/test/test_long.py	Fri May 02 23:26:03 2014 +0200
+++ b/Lib/test/test_long.py	Sat May 03 14:30:04 2014 +0200
@@ -1235,6 +1235,11 @@ class LongTest(unittest.TestCase):
         for n in map(int, integers):
             self.assertEqual(n, 0)
 
+    @support.cpython_only
+    def test_lshift0_id(self):
+        for x in  (0, 10, 50, 12345, 2**100):
+            self.assertIs(x << 0, x)
+
 
 def test_main():
     support.run_unittest(LongTest)
diff -r 62438d1b11c7 Objects/longobject.c
--- a/Objects/longobject.c	Fri May 02 23:26:03 2014 +0200
+++ b/Objects/longobject.c	Sat May 03 14:30:04 2014 +0200
@@ -4118,6 +4118,12 @@ long_lshift(PyObject *v, PyObject *w)
         PyErr_SetString(PyExc_ValueError, "negative shift count");
         return NULL;
     }
+    if (shiftby == 0) {
+        /* x << 0 = x */
+        Py_INCREF(v);
+        return v;
+    }
+
     /* wordshift, remshift = divmod(shiftby, PyLong_SHIFT) */
     wordshift = shiftby / PyLong_SHIFT;
     remshift  = shiftby - wordshift * PyLong_SHIFT;