Interesting. We are running into some odd compiler warnings too with GCC 4.9.1, I filed a Jira on it with some suggested workarounds (neither of which are great ).
Fwiw, Debian "Jessie" comes with 4.9.1, breaking our builds. -- Leif http://lkml.iu.edu//hypermail/linux/kernel/1407.3/00650.html
