https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83298
--- Comment #3 from Jeffrey A. Law <law at redhat dot com> --- I see what's going on here. I'm a bit concerned there's a deeper issue. Some planned gcc-9 work would take care of this, but I was hoping to avoid those changes in the gcc-8 cycle. Investigating the deeper concerns and alternate (less intrusive) fixes.
