https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85571
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- Not yet fixed. As we compare LTO bytecode but that includes the .opts section we now have -f[no-]checking there... We can't remove it there since we of course want to have different settings at link-time. A custom do-compare script like bootstrap-debug.mk provides might be a workaround for this particular issue. Maybe time to finally not compare LTO bytecode (but then we need to compare binaries which we don't do - but we could now that we share the checksums). OTOH stage2 and stage3 cc1 even differ in the size of the .text section... So we have "real" bugs to fix here as well it seems ;)