https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43491
--- Comment #11 from Bill Schmidt <wschmidt at gcc dot gnu.org> --- But hm, on further reading of https://gcc.gnu.org/onlinedocs/gcc/Global-Register-Variables.html, I don't think that the compiler is precluded from using temporary registers to hold the global register value, so long as observable changes to the variable occur in the specified register. So I'll withdraw my concern.
