On Thu, Feb 10, 2022 at 03:17:05PM -0600, Bill Schmidt wrote:
> >> /* 1 argument vector functions added in ISA 3.0 (power9). */
> >> -BU_P9V_AV_1 (VCLZLSBB_V16QI, "vclzlsbb_v16qi", CONST, vclzlsbb_v16qi)
> >> -BU_P9V_AV_1 (VCLZLSBB_V8HI, "vclzlsbb_v8hi", CONST, vclzlsbb_v8hi)
> >> -BU_P9V_AV_1 (VCLZLSBB_V4SI, "vclzlsbb_v4si", CONST, vclzlsbb_v4si)
> >> -BU_P9V_AV_1 (VCTZLSBB_V16QI, "vctzlsbb_v16qi", CONST, vctzlsbb_v16qi)
> >> -BU_P9V_AV_1 (VCTZLSBB_V8HI, "vctzlsbb_v8hi", CONST, vctzlsbb_v8hi)
> >> -BU_P9V_AV_1 (VCTZLSBB_V4SI, "vctzlsbb_v4si", CONST, vctzlsbb_v4si)
> >> +BU_P9V_AV_1 (VCLZLSBB_V16QI, "vclzlsbb_v16qi", CONST, vctzlsbb_v16qi)
> >> +BU_P9V_AV_1 (VCLZLSBB_V8HI, "vclzlsbb_v8hi", CONST, vctzlsbb_v8hi)
> >> +BU_P9V_AV_1 (VCLZLSBB_V4SI, "vclzlsbb_v4si", CONST, vctzlsbb_v4si)
> >> +BU_P9V_AV_1 (VCTZLSBB_V16QI, "vctzlsbb_v16qi", CONST, vclzlsbb_v16qi)
> >> +BU_P9V_AV_1 (VCTZLSBB_V8HI, "vctzlsbb_v8hi", CONST, vclzlsbb_v8hi)
> >> +BU_P9V_AV_1 (VCTZLSBB_V4SI, "vctzlsbb_v4si", CONST, vclzlsbb_v4si)
> > Please change the default to be equal to the builtin name, so, the BE
> > version. We do that everywhere else as well, and it makes a lot more
> > sense (since everything in Power has BE numbering).
> >
> > The trunk version has this correct afaics?
>
> No, trunk has this, for example:
>
> const signed int __builtin_altivec_vclzlsbb_v16qi (vsc);
> VCLZLSBB_V16QI vctzlsbb_v16qi {endian}
I see this on trunk:
const signed int __builtin_altivec_vclzlsbb_v16qi (vsc);
VCLZLSBB_V16QI vclzlsbb_v16qi {}
Oh, you changed it? Please fix it, then.
> Throughout the new builtin infrastructure, the defaults are set for
> little-endian, and the "endian" flag changes behavior for big-endian.
That is a big mistake. There are many machine instructions that are
*always* big-endian (most even!), and none that are always
little-endian. So this should be fixed, sooner rather than later :-(
> >> /* { dg-require-effective-target powerpc_p9vector_ok } */
> >> /* { dg-options "-mdejagnu-cpu=power9" } */
> >> +/* { dg-additional-options "-mbig" { target powerpc64le-*-* } } */
> > You don't need the target clause, if it already is BE by default it does
> > not do anything to add it redundantly.
> >
> > But this is wrong anyway: the name of the target triple does not say
> > whether we are BE or LE. Instead you should use the be or le selectors.
> > But again, just add -mbig always.
>
> This was added by David Edelsohn to the trunk version of the patch, because
> -mbig actually is not supported on all subtargets. (I found that quite
> surprising also.)
Huh. Yeah I think I encountered that before.
So this is because these options are in sysv4.opt .
> Apparently this doesn't work on AIX, for example. But
> -mlittle works everywhere. Go figure.
... and -mlittle is exactly the same? Wtw.
I only looked at the .opt files, maybe one of them is handled directly,
or more likely in specs? And not symmetrically?
> That's something that should be fixed, I guess, but it's orthogonal
> to this patch.
Fixing it later is more work :-(
Please at least open a bug report for it.
The other things need fixing before the patch is okay.
Segher
