Re: GCC 7 on ppc64le does not recognize vec_xl_be?

[Jonathan Wakely <jwakely.gcc@gmail.com>]

On Sat, 16 Nov 2019 at 21:25, Jeffrey Walton <noloader@gmail.com> 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.
>
> The problems with GCC seem to be a little larger then inaccurate docs.

What? You're talking nonsense.

You said:
"According to the GCC docs vec_xl_be is available with ISA 3.0:
https://gcc.gnu.org/onlinedocs/gcc/PowerPC-AltiVec-Built-in-Functions-Available-on-ISA-3_002e0.html
"

You are consulting the docs for GCC trunk and assuming they apply to
GCC 7. That's simply wrong.

The corresponding docs for GCC 7 are at:
https://gcc.gnu.org/onlinedocs/gcc-7.5.0/gcc/PowerPC-AltiVec_002fVSX-Built-in-Functions.html#PowerPC-AltiVec_002fVSX-Built-in-Functions

It doesn't mention vec_xl_be in the functions available with
-mcpu=power9. So why do you think GCC 7 might not recognise that
function? Hmm, maybe because it isn't supported by GCC 7.

The docs are accurate. The docs for GCC 7 say which functions
-mcpu=power9 enables FOR GCC 7, and that doesn't include the function
you're trying to use.

The docs for GCC trunk say which functions -mcpu-power9 enables FOR
GCC TRUNK. Not for all versions. The intro to the pages you're looking
at says "It corresponds to the compilers (GCC) version 10.0.0." so
you're simply wrong to assume it also corresponds to older versions.
It doesn't. For older versions, see the docs for those versions.