diff -r f592a4073672 Objects/unicodeobject.c
--- a/Objects/unicodeobject.c	Sat Oct 11 01:43:35 2014 -0500
+++ b/Objects/unicodeobject.c	Sat Oct 11 10:41:49 2014 +0100
@@ -4837,7 +4837,7 @@
 
     /* Note: size will always be longer than the resulting Unicode
        character count */
-    if (PY_SSIZE_T_MAX / sizeof(wchar_t) < (size + 1))
+    if (PY_SSIZE_T_MAX / sizeof(wchar_t) < (unsigned long) (size + 1))
         return NULL;
     unicode = PyMem_RawMalloc((size + 1) * sizeof(wchar_t));
     if (!unicode)