https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70814
--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Richard Earnshaw from comment #8)
> (In reply to Andrew Pinski from comment #7)
> > Closing as invalid. Though for v8.4 or so it would be nice if there was
> > 128bit atomic loads.
>
> That probably wouldn't help. It would require a new ABI before you could
> use them, since all code has to swap to that mechanism. Iff you could
> guarantee that an application had exactly one instance of
> __atomic_{load,store}_16 (ie that it isn't a private function in each DSO
> component), then you *might* be able to re-implement those routines using
> the new instructions, but otherwise you're stuck with the requirement to
> retain backwards compatibility.
On x86, they use ifuncs for this purpose inside libatomic. Basically the
requirement is only one libatomic can be used at a time.
