[PATCH V2] arm: [testcase] Better narrow some bfloat16 testcase

[Christophe Lyon]

On Fri, 6 Nov 2020 at 15:06, Andrea Corallo <andrea.corallo@arm.com> wrote:
>
> Christophe Lyon <christophe.lyon@linaro.org> writes:
>
> > On Thu, 5 Nov 2020 at 15:30, Andrea Corallo <andrea.corallo@arm.com> wrote:
> >>
> >> Christophe Lyon <christophe.lyon@linaro.org> writes:
> >>
> >> > On Thu, 5 Nov 2020 at 12:11, Andrea Corallo <andrea.corallo@arm.com> wrote:
> >> >>
> >> >> Christophe Lyon <christophe.lyon@linaro.org> writes:
> >> >>
> >> >> [...]
> >> >>
> >> >> >> I think you need to add -mfloat-abi=hard to the dg-additional-options
> >> >> >> otherwise vld1_lane_bf16_1.c
> >> >> >> fails on targets with a soft float-abi default (eg arm-linux-gnueabi).
> >> >> >>
> >> >> >> See bf16_vldn_1.c.
> >> >> >
> >> >> > Actually that's not sufficient because in turn we get:
> >> >> > /sysroot-arm-none-linux-gnueabi/usr/include/gnu/stubs.h:10:11: fatal
> >> >> > error: gnu/stubs-hard.h: No such file or directory
> >> >> >
> >> >> > So you should check that -mfloat-abi=hard is supported.
> >> >> >
> >> >> > Ditto for the vst tests.
> >> >>
> >> >> Hi Christophe,
> >> >>
> >> >> this patch should implement your suggestions.
> >> >>
> >> >> On my arm-none-linux-gnueabi setup the tests were already skipped
> >> >> as unsupported so if you could test and confirm this fixes the
> >> >> issue you see would be great.
> >> >
> >> > Do you know why they are unsupported in your setup?
> >>
> >> We probably have a different GCC configuration.  Could you share how
> >> it's configured your?
> >>
> > Sure, for instance:
> > --target=arm-none-linux-gnueabi --with-float=soft --with-mode=arm
> > --with-cpu=cortex-a9
>
> Thanks, I see now what was going on, my gas has no bf16 support so the
> test was marked as unsupported.  Dunno why I assumed
> check_no_compiler_messages_nocache wasn't testing the whole compilation
> process.
>
> >> >> diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
> >> >> index 15f0649f8ae..2ab7e39756d 100644
> >> >> --- a/gcc/testsuite/lib/target-supports.exp
> >> >> +++ b/gcc/testsuite/lib/target-supports.exp
> >> >> @@ -5213,6 +5213,10 @@ proc check_effective_target_arm_v8_2a_bf16_neon_ok_nocache { } {
> >> >>          return 0;
> >> >>      }
> >> >>
> >> >> +    if { ! [check_effective_target_arm_hard_ok] } {
> >> >> + return 0;
> >> >> +    }
> >> >> +
> >> >>     foreach flags {"" "-mfloat-abi=hard -mfpu=neon-fp-armv8" "-mfloat-abi=softfp -mfpu=neon-fp-armv8" } {
> >> >>         if { [check_no_compiler_messages_nocache arm_v8_2a_bf16_neon_ok object {
> >> >>             #include <arm_neon.h>
> >> >
> >> > This seems strange since you would now exit early if
> >> > check_effective_target_arm_hard_ok is false, so you'll never need the
> >> > -mfloat-abi=softfp version of the flags.
> >>
> >> So IIUC your suggestion would be to test with higher priority softfp and
> >> in case we decide to go for hardfp make sure
> >> check_effective_target_arm_hard_ok is satisfied.  Am I correct?
> >>
> > ISTM that other tests that need hardfp check if it's supported in the
> > test, not in other effective targets.
> >
> > For instance mve/intrinsics/mve_fpu1.c
> >
> > I can see that quite a few tests that use -mfloat-abi=hard do not
> > check whether it's supported. Those I checked do not include
> > arm_neon.h and thus do not end up with the gnu/stubs-hard.h error
> > above.
>
> I see thanks for the explaination.  The attached should do the job.
>

Yes, it works for me, thanks.

>   Andrea
>