[PATCH][vectorizer][2/2] Hook up mult synthesis logic into vectorisation of mult-by-constant

[Kyrill Tkachov]

On 06/07/16 13:40, Kyrill Tkachov wrote:
>
> On 06/07/16 13:31, Rainer Orth wrote:
>> Hi Kyrill,
>>
>>> On 05/07/16 12:24, Rainer Orth wrote:
>>>> Marc Glisse <marc.glisse@inria.fr> writes:
>>>>
>>>>> On Tue, 5 Jul 2016, Kyrill Tkachov wrote:
>>>>>
>>>>>> As for testing I've bootstrapped and tested the patch on aarch64 and
>>>>>> x86_64 with synth_shift_p in vect_synth_mult_by_constant hacked to be
>>>>>> always true to exercise the paths that synthesize the shift by
>>>>>> additions. Marc, could you test this on the sparc targets you care about?
>>>>> I don't have access to Sparc, you want Rainer here (added in Cc:).
>>>> As is, the patch doesn't even build on current mainline:
>>>>
>>>> /vol/gcc/src/hg/trunk/local/gcc/tree-vect-patterns.c:2151:56: error: 'mult_variant' has not been declared
>>>>    target_supports_mult_synth_alg (struct algorithm *alg, mult_variant var,
>>>>                                                           ^
>>>>
>>>> enum mult_variant is only declared in expmed.c.
>>> Ah, sorry I forgot to mention that this is patch 2/2.
>>> It requires https://gcc.gnu.org/ml/gcc-patches/2016-06/msg01144.html which
>>> is already approved
>>> but I was planning to commit it together with this one.
>>> Can you please try applying
>>> https://gcc.gnu.org/ml/gcc-patches/2016-06/msg01144.html
>>> as well as this?
>> sure, that did the trick.  A sparc-sun-solaris2.12 bootstrap revealed
>> that the patch fixes PR tree-optimization/70923 (you should mention that
>> in the ChangeLog or close it as a duplicate), with the same caveat as
>> about Marc's latest patch for that:
>
> Thanks! Much appreciated.
>
>> +FAIL: gcc.dg/vect/vect-iv-9.c -flto -ffat-lto-objects  scan-tree-dump-times vect "vectorized 1 loops" 1
>> +FAIL: gcc.dg/vect/vect-iv-9.c scan-tree-dump-times vect "vectorized 1 loops" 1
>>
>> The message appears twice, not once, on sparc, so the testcase should be
>> updated to accomodate that.
>
> Ok.
>
>> Besides, the new testcase FAILs:
>>
>> +FAIL: gcc.dg/vect/pr65951.c -flto -ffat-lto-objects scan-tree-dump-times vect "vectorized 1 loops" 2
>> +FAIL: gcc.dg/vect/pr65951.c scan-tree-dump-times vect "vectorized 1 loops" 2
>>
>> The dump contains
>>
>> gcc.dg/vect/pr65951.c:14:3: note: not vectorized: no vectype for stmt: _4 = *_3;
>> gcc.dg/vect/pr65951.c:12:1: note: vectorized 0 loops in function.
>> gcc.dg/vect/pr65951.c:21:3: note: not vectorized: no vectype for stmt: _4 = *_3;
>> gcc.dg/vect/pr65951.c:19:1: note: vectorized 0 loops in function.
>> gcc.dg/vect/pr65951.c:55:15: note: not vectorized: control flow in loop.
>> gcc.dg/vect/pr65951.c:46:3: note: not vectorized: loop contains function calls or data references that cannot be analyzed
>> gcc.dg/vect/pr65951.c:41:15: note: not vectorized: control flow in loop.
>> gcc.dg/vect/pr65951.c:32:3: note: not vectorized: loop contains function calls or data references that cannot be analyzed
>> gcc.dg/vect/pr65951.c:26:1: note: vectorized 0 loops in function.
>
> I see. I suppose SPARC doesn't have vector shifts operating on 64-bit data?
> I believe the testcase should be updated to use just "int" arrays rather than "long long".
>
> I'll respin the testcases

Ok, here's the patch with pr65951.c updated to use int rather than long long arrays and vect-iv-9.c updated to scan for the
"Vectorized 1 loops" string twice. I've verified by hand by building a sparc-sun-solaris2.10 cc1 that compiling with
-mcpu=ultrasparc -mvis gives the right strings in the vectoriser dump.

So is this version ok?

Thanks,
Kyrill


2016-07-06  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

     PR target/65951
     PR tree-optimization/70923
     * tree-vect-patterns.c: Include mult-synthesis.h.
     (target_supports_mult_synth_alg): New function.
     (synth_lshift_by_additions): Likewise.
     (apply_binop_and_append_stmt): Likewise.
     (vect_synth_mult_by_constant): Likewise.
     (target_has_vecop_for_code): Likewise.
     (vect_recog_mult_pattern): Use above functions to synthesize vector
     multiplication by integer constants.

2016-07-06  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

     PR target/65951
     PR tree-optimization/70923
     * gcc.dg/vect/vect-mult-const-pattern-1.c: New test.
     * gcc.dg/vect/vect-mult-const-pattern-2.c: Likewise.
     * gcc.dg/vect/pr65951.c: Likewise.
     * gcc.dg/vect/vect-iv-9.c: Remove ! vect_int_mult-specific scan.

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