[Bug middle-end/91395] Report an uninitialized variable on its initialization statement (setjmp)

[pinskia at gcc dot gnu.org]

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.