[Bug rtl-optimization/81501] mulitple calls to __tls_get_addr() with -fPIC

[yann at droneaud dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81501

--- Comment #7 from Yann Droneaud <yann at droneaud dot fr> ---
(In reply to Roy Jacobson from comment #6)
> We recently upgraded our toolchain from GCC9 to GCC11, and we're seeing
> __tls_get_addr take up to 10% of total runtime under some workloads, where
> it was 1-2% before.
> 
> It seems that some changes to the optimization passes in 10 or 11 have
> significantly increased the impact of this problem.

In bug #82803, comment #12,
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82803#c12), I've shown a
workaround I used, which might be useful until GCC handle __tls_get_addr() as
returning a constant addresses that doesn't need to be looked up multiple times
in a function.