[Bug middle-end/121352] tls_model attribute documentation needs update

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121352

--- Comment #1 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
That patch deliberately takes care not to optimize in presence of the
attribute:

          /* Upgrade TLS access model based on optimized visibility status,
             unless it was specified explicitly or no references remain.  */
          if (DECL_THREAD_LOCAL_P (decl)
              && !lookup_attribute ("tls_model", DECL_ATTRIBUTES (decl))
              && vnode->ref_list.referring.length ())
            {