Re: [musl] Adding PowerPC SPE support

[Arnd Bergmann <arnd@kernel.org>]

On Sun, Jun 6, 2021 at 12:05 AM Rich Felker <dalias@libc.org> wrote:
> On Sat, Jun 05, 2021 at 11:15:04PM +0200, Arnd Bergmann wrote:
> > On Sat, Jun 5, 2021 at 7:12 PM Rich Felker <dalias@libc.org> wrote:
> > >
> > > When the soft-float ABI for PowerPC was added in 2016 (commit
> > > 5a92dd95c77cee81755f1a441ae0b71e3ae2bcdb, mail thread "[PATCH v3] Add
> > > PowerPC soft-float support") with Freescale cpus having the
> > > alternative SPE FPU as the main use case, I noted that we could
> > > probably support hard float on them, but that it would involve
> > > determining some difficult ABI constraints. I'm now revisiting adding
> > > this support.
> >
> > Note that regardless of the technical issues, there is a practical problem
> > in the long run, since gcc-8.5 was the last release with powerpcspe
> > support, and at some point in the future everyone will move to gcc-9
> > or higher.
>
> Yes, llvm has added it though and presumably ppl who want it will just
> use clang or stick with old gcc (which makes me sad, but that's how it is).

Ah, I hadn't noticed llvm support for it. It looks like Justin Hibbits
contributed it for his work on FreeBSD, which is moving away from gcc
anway. FreeBSD 12.x have started listing powerpcspe as a "Tier 2"
supported architecture, so it seems likely they are more active than
Linux on this hardware now.

       Arnd