GCC 7 on ppc64le does not recognize vec_xl_be?

[Segher Boessenkool]

On Sat, Nov 16, 2019 at 04:25:18PM -0500, Jeffrey Walton wrote:
> On Sat, Nov 16, 2019 at 1:26 PM Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
> >  ...
> > I already sent the following to Jeffrey 8 hours ago (off-list, because
> > I could only send HTML mail at the time):
> >
> > "Those are the docs for GCC trunk. That function is not listed in the
> > docs for GCC 7."
> 
> GCC tells me it supports the load by accepting -mcpu=power9 and
> defining _ARCH_PWR9.

It does no such thing.  GCC does not claim it implements this, and the
ELF v2 spec says "The two optional built-in vector functions in Table
6.4 [...]", and defines no specific way to detect it either.

> The problems with GCC seem to be a little larger then inaccurate docs.

The GCC docs are perfectly accurate for this as well.

GCC 7 is older than this revision of the ELFv2 specification, and we never
backported this feature: only very important features are backported.  It
could have made 7.2, over two years ago, but it wasn't considered important
enough to backport.


Segher