https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64491
--- Comment #10 from Andrew Stubbs <ams at gcc dot gnu.org> --- I'm trying to look at this problem, but so far all my builds are failing. Probably I have some local cruft. In the meantime, the workaround is to use -Wno-aggressive-loop-optimizations, I think.