https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111096
--- Comment #3 from Thomas Koenig <tkoenig at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #2) > See https://gcc.gnu.org/pipermail/gcc-patches/2016-September/456662.html > > I think this is by design of the ABI ... The workaround mentioned in the thread does not appear to work, -O3 -fomit-frame-pointer -fcall-used-x29 yields cc1: error: cannot use 'x29' as a call-used register
