diff -r 5b0fda8f5718 Objects/longobject.c
--- a/Objects/longobject.c	Fri May 02 22:31:14 2014 +0200
+++ b/Objects/longobject.c	Fri May 02 23:06:22 2014 +0200
@@ -180,27 +180,37 @@ PyLongObject *
 #define MAX_LONG_DIGITS \
     ((PY_SSIZE_T_MAX - offsetof(PyLongObject, ob_digit))/sizeof(digit))
 
+static PyLongObject *
+long_alloc(Py_ssize_t ndigits, int use_calloc)
+{
+    PyLongObject *result;
+    Py_ssize_t size;
+    /* Number of bytes needed is: offsetof(PyLongObject, ob_digit) +
+       sizeof(digit)*ndigits.  Previous incarnations of this code used
+       sizeof(PyVarObject) instead of the offsetof, but this risks being
+       incorrect in the presence of padding between the PyVarObject header
+       and the digits. */
+    if (ndigits > (Py_ssize_t)MAX_LONG_DIGITS) {
+        PyErr_SetString(PyExc_OverflowError,
+                        "too many digits in integer");
+        return NULL;
+    }
+    size = offsetof(PyLongObject, ob_digit) + ndigits * sizeof(digit);
+    if (use_calloc)
+        result = PyObject_Calloc(1, size);
+    else
+        result = PyObject_Malloc(size);
+    if (!result) {
+        PyErr_NoMemory();
+        return NULL;
+    }
+    return (PyLongObject*)PyObject_INIT_VAR(result, &PyLong_Type, ndigits);
+}
+
 PyLongObject *
 _PyLong_New(Py_ssize_t size)
 {
-    PyLongObject *result;
-    /* Number of bytes needed is: offsetof(PyLongObject, ob_digit) +
-       sizeof(digit)*size.  Previous incarnations of this code used
-       sizeof(PyVarObject) instead of the offsetof, but this risks being
-       incorrect in the presence of padding between the PyVarObject header
-       and the digits. */
-    if (size > (Py_ssize_t)MAX_LONG_DIGITS) {
-        PyErr_SetString(PyExc_OverflowError,
-                        "too many digits in integer");
-        return NULL;
-    }
-    result = PyObject_MALLOC(offsetof(PyLongObject, ob_digit) +
-                             size*sizeof(digit));
-    if (!result) {
-        PyErr_NoMemory();
-        return NULL;
-    }
-    return (PyLongObject*)PyObject_INIT_VAR(result, &PyLong_Type, size);
+    return long_alloc(size, 0);
 }
 
 PyObject *
@@ -4126,15 +4136,13 @@ long_lshift(PyObject *v, PyObject *w)
     newsize = oldsize + wordshift;
     if (remshift)
         ++newsize;
-    z = _PyLong_New(newsize);
+    z = long_alloc(newsize, 1);
     if (z == NULL)
         return NULL;
     if (Py_SIZE(a) < 0) {
         assert(Py_REFCNT(z) == 1);
         Py_SIZE(z) = -Py_SIZE(z);
     }
-    for (i = 0; i < wordshift; i++)
-        z->ob_digit[i] = 0;
     accum = 0;
     for (i = wordshift, j = 0; j < oldsize; i++, j++) {
         accum |= (twodigits)a->ob_digit[j] << remshift;