Hi!
On 2/10/22 2:50 PM, Segher Boessenkool wrote:
> On Thu, Feb 10, 2022 at 12:22:28PM -0600, Bill Schmidt wrote:
>> This is a backport from mainline 3f30f2d1dbb3228b8468b26239fe60c2974ce2ac.
>> These built-ins were misimplemented as always having big-endian semantics.
>>
>> Because the built-in infrastructure has changed, the modifications to the
>> source are different but achieve the same purpose. The modifications to
>> the test suite are identical (after fixing the issue with -mbig that David
>> pointed out with the original patch).
>> /* 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}
So the backport matches what is on trunk.
Throughout the new builtin infrastructure, the defaults are set for
little-endian, and the "endian" flag changes behavior for big-endian.
>
>> --- a/gcc/testsuite/gcc.target/powerpc/vsu/vec-cntlz-lsbb-0.c
>> +++ b/gcc/testsuite/gcc.target/powerpc/vsu/vec-cntlz-lsbb-0.c
>> @@ -1,6 +1,7 @@
>> /* { dg-do compile { target { powerpc*-*-* } } } */
> (Delete the redundant target clause when modifying any testcase, please).
Okay.
>
>> /* { 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.) Apparently this doesn't work on AIX, for example. But
-mlittle works everywhere. Go figure.
That's something that should be fixed, I guess, but it's orthogonal
to this patch.
Thanks!
Bill
>
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/vsu/vec-cntlz-lsbb-3.c
>> @@ -0,0 +1,15 @@
>> +/* { dg-do compile { target { powerpc*-*-* } } } */
>> +/* { dg-require-effective-target powerpc_p9vector_ok } */
>> +/* { dg-options "-mdejagnu-cpu=power9 -mlittle" } */
> And here you do it correctly :-)
>
> Okay with those fixes (all happen a few times). Thanks!
>
>
> Segher
