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Re: Add support for bitwise reductions


On 26 January 2018 at 10:33, Richard Sandiford
<richard.sandiford@linaro.org> wrote:
> Christophe Lyon <christophe.lyon@linaro.org> writes:
>> On 25 January 2018 at 11:24, Richard Sandiford
>> <richard.sandiford@linaro.org> wrote:
>>> Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE> writes:
>>>> Jeff Law <law@redhat.com> writes:
>>>>> On 11/22/2017 11:12 AM, Richard Sandiford wrote:
>>>>>> Richard Sandiford <richard.sandiford@linaro.org> writes:
>>>>>>> This patch adds support for the SVE bitwise reduction instructions
>>>>>>> (ANDV, ORV and EORV).  It's a fairly mechanical extension of existing
>>>>>>> REDUC_* operators.
>>>>>>>
>>>>>>> Tested on aarch64-linux-gnu (with and without SVE), x86_64-linux-gnu
>>>>>>> and powerpc64le-linux-gnu.
>>>>>>
>>>>>> Here's an updated version that applies on top of the recent
>>>>>> removal of REDUC_*_EXPR.  Tested as before.
>>>>>>
>>>>>> Thanks,
>>>>>> Richard
>>>>>>
>>>>>>
>>>>>> 2017-11-22  Richard Sandiford  <richard.sandiford@linaro.org>
>>>>>>         Alan Hayward  <alan.hayward@arm.com>
>>>>>>         David Sherwood  <david.sherwood@arm.com>
>>>>>>
>>>>>> gcc/
>>>>>>     * optabs.def (reduc_and_scal_optab, reduc_ior_scal_optab)
>>>>>>     (reduc_xor_scal_optab): New optabs.
>>>>>>     * doc/md.texi (reduc_and_scal_@var{m}, reduc_ior_scal_@var{m})
>>>>>>     (reduc_xor_scal_@var{m}): Document.
>>>>>>     * doc/sourcebuild.texi (vect_logical_reduc): Likewise.
>>>>>>     * internal-fn.def (IFN_REDUC_AND, IFN_REDUC_IOR, IFN_REDUC_XOR): New
>>>>>>     internal functions.
>>>>>>     * fold-const-call.c (fold_const_call): Handle them.
>>>>>>     * tree-vect-loop.c (reduction_fn_for_scalar_code): Return the new
>>>>>>     internal functions for BIT_AND_EXPR, BIT_IOR_EXPR and BIT_XOR_EXPR.
>>>>>>     * config/aarch64/aarch64-sve.md (reduc_<bit_reduc>_scal_<mode>):
>>>>>>     (*reduc_<bit_reduc>_scal_<mode>): New patterns.
>>>>>>     * config/aarch64/iterators.md (UNSPEC_ANDV, UNSPEC_ORV)
>>>>>>     (UNSPEC_XORV): New unspecs.
>>>>>>     (optab): Add entries for them.
>>>>>>     (BITWISEV): New int iterator.
>>>>>>     (bit_reduc_op): New int attributes.
>>>>>>
>>>>>> gcc/testsuite/
>>>>>>     * lib/target-supports.exp (check_effective_target_vect_logical_reduc):
>>>>>>     New proc.
>>>>>>     * gcc.dg/vect/vect-reduc-or_1.c: Also run for vect_logical_reduc
>>>>>>     and add an associated scan-dump test.  Prevent vectorization
>>>>>>     of the first two loops.
>>>>>>     * gcc.dg/vect/vect-reduc-or_2.c: Likewise.
>>>>>>     * gcc.target/aarch64/sve_reduc_1.c: Add AND, IOR and XOR reductions.
>>>>>>     * gcc.target/aarch64/sve_reduc_2.c: Likewise.
>>>>>>     * gcc.target/aarch64/sve_reduc_1_run.c: Likewise.
>>>>>>     (INIT_VECTOR): Tweak initial value so that some bits are always set.
>>>>>>     * gcc.target/aarch64/sve_reduc_2_run.c: Likewise.
>>>>> OK.
>>>>> Jeff
>>>>
>>>> Two tests have regressed on sparc-sun-solaris2.*:
>>>>
>>>> +FAIL: gcc.dg/vect/vect-reduc-or_1.c -flto -ffat-lto-objects
>>>> scan-tree-dump vect "Reduce using vector shifts"
>>>> +FAIL: gcc.dg/vect/vect-reduc-or_1.c scan-tree-dump vect "Reduce using
>>>> vector shifts"
>>>> +FAIL: gcc.dg/vect/vect-reduc-or_2.c -flto -ffat-lto-objects
>>>> scan-tree-dump vect "Reduce using vector shifts"
>>>> +FAIL: gcc.dg/vect/vect-reduc-or_2.c scan-tree-dump vect "Reduce using
>>>> vector shifts"
>>>
>>> Bah, I think I broke this yesterday in:
>>>
>>> 2018-01-24  Richard Sandiford  <richard.sandiford@linaro.org>
>>>
>>>         PR testsuite/83889
>>>         [...]
>>>         * gcc.dg/vect/vect-reduc-or_1.c: Remove conditional dg-do run.
>>>         * gcc.dg/vect/vect-reduc-or_2.c: Likewise.
>>>
>>> (r257022), which removed:
>>>
>>>   /* { dg-do run { target { whole_vector_shift || vect_logical_reduc } } } */
>>>
>>> I'd somehow thought that the dump lines in these two tests were already
>>> guarded, but they weren't.
>>>
>>> Tested on aarch64-linux-gnu and x86_64-linux-gnu and applied as obvious.
>>> Sorry for the breakage.
>>>
>>> Richard
>>>
>>>
>>
>> Hi Richard,
>>
>> While this fixes the regression on armeb (same as on sparc), the
>> effect on arm-none-linux-gnueabi and arm-none-eabi
>> is that the tests are now skipped, while they used to pass.
>> Is this expected? Or is the guard you added too restrictive?
>
> I think that means that the tests went from UNSUPPORTED to PASS on
> the last two targets with r257022.  Is that right?
>
Yes, that's what I meant.

> It's expected in the sense that whole_vector_shift isn't true for
> any arm*-*-* target, and historically this test was restricted to
> whole_vector_shift (apart from the blip this week).
>
OK, then. Just surprising to see PASS disappear.

Thanks,

Christophe

> Thanks,
> Richard
>
>> Thanks,
>>
>> Christophe
>>
>>> 2018-01-25  Richard Sandiford  <richard.sandiford@linaro.org>
>>>
>>> gcc/testsuite/
>>>         * gcc.dg/vect/vect-reduc-or_1.c: Require whole_vector_shift for
>>>         the shift dump line.
>>>         * gcc.dg/vect/vect-reduc-or_2.c: Likewise.
>>>
>>> Index: gcc/testsuite/gcc.dg/vect/vect-reduc-or_1.c
>>> ===================================================================
>>> --- gcc/testsuite/gcc.dg/vect/vect-reduc-or_1.c 2018-01-24 16:22:31.724089913 +0000
>>> +++ gcc/testsuite/gcc.dg/vect/vect-reduc-or_1.c 2018-01-25 10:16:16.283500281 +0000
>>> @@ -45,5 +45,5 @@ main (unsigned char argc, char **argv)
>>>    return 0;
>>>  }
>>>
>>> -/* { dg-final { scan-tree-dump "Reduce using vector shifts" "vect" { target { ! vect_logical_reduc } } } } */
>>> +/* { dg-final { scan-tree-dump "Reduce using vector shifts" "vect" { target { whole_vector_shift && { ! vect_logical_reduc } } } } } */
>>>  /* { dg-final { scan-tree-dump "Reduce using direct vector reduction" "vect" { target vect_logical_reduc } } } */
>>> Index: gcc/testsuite/gcc.dg/vect/vect-reduc-or_2.c
>>> ===================================================================
>>> --- gcc/testsuite/gcc.dg/vect/vect-reduc-or_2.c 2018-01-24 16:22:31.724089913 +0000
>>> +++ gcc/testsuite/gcc.dg/vect/vect-reduc-or_2.c 2018-01-25 10:16:16.284500239 +0000
>>> @@ -44,5 +44,5 @@ main (unsigned char argc, char **argv)
>>>    return 0;
>>>  }
>>>
>>> -/* { dg-final { scan-tree-dump "Reduce using vector shifts" "vect" { target { ! vect_logical_reduc } } } } */
>>> +/* { dg-final { scan-tree-dump "Reduce using vector shifts" "vect" { target { whole_vector_shift && { ! vect_logical_reduc } } } } } */
>>>  /* { dg-final { scan-tree-dump "Reduce using direct vector reduction" "vect" { target vect_logical_reduc } } } */


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