[Bug tree-optimization/65712] pthread_self prints wrong result when used with ucontext

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65712

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I think this is invalid as pthread_self is marked as const or pure which means
it does not change with respect of function calls.

If anything is a deficiency in POSIX.