https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65953
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Jakub Jelinek from comment #1) > Looks like a Mono bug to me. mono_jit_tls isn't __attribute__((used)), and > the compiler determines it is a write-only variable (doesn't know the asm > uses it). I can think of one reason, the whole Coroutines and switching of the thread behind the compiler with getcontext/setcontext.