Re: [testsuite][ARM target attributes] Fix effective_target tests

[Christophe Lyon <christophe dot lyon at linaro dot org>]

On 8 December 2015 at 11:50, Kyrill Tkachov <kyrylo.tkachov@arm.com> wrote:
> Hi Christophe,
>
>
> On 27/11/15 13:00, Christophe Lyon wrote:
>>
>> Hi,
>>
>> After the recent commits from Christian adding target attributes
>> support for ARM FPU settings,  I've noticed that some of the tests
>> were failing because of incorrect assumptions wrt to the default
>> cpu/fpu/float-abi of the compiler.
>>
>> This patch fixes the problems I've noticed in the following way:
>> - do not force -mfloat-abi=softfp in dg-options, to avoid conflicts
>> when gcc is configured --with-float=hard
>>
>> - change arm_vfp_ok such that it tries several -mfpu/-mfloat-abi
>> flags, checks that __ARM_FP is defined and __ARM_NEON_FP is not
>> defined
>>
>> - introduce arm_fp_ok, which is similar but does not enforce fpu setting
>>
>> - add a new effective_target: arm_crypto_pragma_ok to check that
>> setting this fpu via a pragma is actually supported by the current
>> "multilib". This is different from checking the command-line option
>> because the pragma might conflict with the command-line options in
>> use.
>>
>> The updates in the testcases are as follows:
>> - attr-crypto.c, we have to make sure that the defaut fpu does not
>> conflict with the one forced by pragma. That's why I use the arm_vfp
>> options/effective_target. This is needed if gcc has been configured
>> --with-fpu=neon-fp16, as the pragma fpu=crypto-neon-fp-armv8 would
>> conflict.
>>
>> - attr-neon-builtin-fail.c: use arm_fp to force the appropriate
>> float-abi setting. Enforcing fpu is not needed here.
>>
>> - attr-neon-fp16.c: similar, I also removed arm_neon_ok since it was
>> not necessary to make the test pass in my testing. On second thought,
>> I'm wondering whether I should leave it and make the test unsupported
>> in more cases (such as when forcing -march=armv5t, although it does
>> pass with this patch)
>>
>> - attr-neon2.c: use arm_vfp to force the appropriate float-abi
>> setting. Enforcing mfpu=vfp is needed to avoid conflict with the
>> pragma target fpu=neon (for instance if the toolchain default is
>> neon-fp16)
>>
>> - attr-neon3.c: similar
>>
>> Tested on a variety of configurations, see:
>>
>> http://people.linaro.org/~christophe.lyon/cross-validation/gcc-test-patches/230929-target-attr/report-build-info.html
>>
>> Note that the regressions reported fall into 3 categories:
>> - when forcing march=armv5t: tests are now unsupported because I
>> modified arm_crypto_ok to require arm_v8_neon_ok instead of arm32.
>>
>> - the warning reported by attr-neon-builtin-fail.c moved from line 12
>> to 14 and is thus seen as a regression + one improvement
>>
>> - finally, attr-neon-fp16.c causes an ICE on armeb compilers, for
>> which I need to post a bugzilla.
>>
>>
>> TBH, I'm a bit concerned by the complexity of all these multilib-like
>> conditions. I'm confident that I'm still missing some combinations :-)
>>
>> And with new target attributes coming, new architectures etc... all
>> this logic is likely to become even more complex.
>>
>> That being said, OK for trunk?
>
>
> I'd like us to clean up and reorganise the gcc.target/arm testsuite
> at some point to make it more robust with respect to the tons of multilib
> options and configurations we can have for arm. It's becoming very
> frustrating
> to test feature-specific stuff :(
>
> This is ok in the meantime.
> Sorry for the delay.
>

Thanks for the approval, glad to see I'm not the only one willing to see
improvements in this area :)

Committed as r231403.

Christophe.

> Thanks for handling this!
> Kyrill
>
>
>> Christophe
>>
>>
>> 2015-11-27  Christophe Lyon  <christophe.lyon@linaro.org>
>>
>>      * lib/target-supports.exp
>>      (check_effective_target_arm_vfp_ok_nocache): New.
>>      (check_effective_target_arm_vfp_ok): Call the new
>>      check_effective_target_arm_vfp_ok_nocache function.
>>      (check_effective_target_arm_fp_ok_nocache): New.
>>      (check_effective_target_arm_fp_ok): New.
>>      (add_options_for_arm_fp): New.
>>      (check_effective_target_arm_crypto_ok_nocache): Require
>>      target_arm_v8_neon_ok instead of arm32.
>>      (check_effective_target_arm_crypto_pragma_ok_nocache): New.
>>      (check_effective_target_arm_crypto_pragma_ok): New.
>>      (add_options_for_arm_vfp): New.
>>      * gcc.target/arm/attr-crypto.c: Use arm_crypto_pragma_ok effective
>>      target. Do not force -mfloat-abi=softfp, use arm_vfp effective
>>      target instead.
>>      * gcc.target/arm/attr-neon-builtin-fail.c: Do not force
>>      -mfloat-abi=softfp, use arm_fp effective target instead.
>>      * gcc.target/arm/attr-neon-fp16.c: Likewise. Remove arm_neon_ok
>>      dependency.
>>      * gcc.target/arm/attr-neon2.c: Do not force -mfloat-abi=softfp,
>>      use arm_vfp effective target instead.
>>      * gcc.target/arm/attr-neon3.c: Likewise.
>
>