https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91395
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Component|c |middle-end Resolution|--- |INVALID --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- The warning is correct due to the way sigsetjmp works. You need to mark save_exception_stack as volatile to fix the issue. Basically any non-volatile variable in the function scope can be incorrect. This is what the POSIX (and C standard for setjmp) says. GCC is just taking into account this now.