https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77567
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Created attachment 39611 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39611&action=edit pr77567-1.patch This (version for current compiler-rt, for gcc it needs a one-liner tweak in the // See line - different URL) seems to work fine in my limited testing and passed bootstrap/regtest, but isn't able to diagnose bug like you have in your testcase.