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Re: [PATCH, PR52252] Alternative way of vectorization for load groups of size 2 and 3.
- From: Evgeny Stupachenko <evstupac at gmail dot com>
- To: ramrad01 at arm dot com
- Cc: Richard Biener <rguenther at suse dot de>, Uros Bizjak <ubizjak at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Jakub Jelinek <jakub at redhat dot com>
- Date: Thu, 5 Jun 2014 15:43:55 +0400
- Subject: Re: [PATCH, PR52252] Alternative way of vectorization for load groups of size 2 and 3.
- Authentication-results: sourceware.org; auth=none
- References: <CAOvf_xz4y6u9-YZCdTM8j3Awm7pdARvyb-58=obT+U9Tkt0HNg at mail dot gmail dot com> <CAJA7tRb4qV7PCbYSQzkFRnP4TkqqvZiA4nmCmopCzCCvDs-THw at mail dot gmail dot com>
New hook is related to vector instructions only. Vector instructions
could be sequential in pipeline, but scalar - parallel. For x86
architectures TARGET_SCHED_REASSOC_WIDTH does not give required
General hooks could be potentially reused in other algorithms/by other
On Thu, Jun 5, 2014 at 2:04 PM, Ramana Radhakrishnan
> On Wed, May 28, 2014 at 2:09 PM, Evgeny Stupachenko <firstname.lastname@example.org> wrote:
>> The patch introduces alternative way of permutations for load groups
>> of size 2 and 3 which should be faster on architectures with low
>> The patch gives 2 times gain on Silvermont to the test from PR52252
>> (in addition to already committed 3 times gain).
>> Patch passes bootstrap on x86. Make check is in progress.
> Why do we need a new hook ? Can't you derive this information from
> something which is equally badly named TARGET_SCHED_REASSOC_WIDTH
> though used in the reassociation logic but also serves a similar
> purpose ?
> Also the documentation of this hook is incomplete at best and wrong at
> worst as this is not applied everywhere in the vectorizer but just for
> this special case for load store permuting. Implying this is useful
> everywhere in the vectorizer does not appear to be correct.
>> 2014-05-28 Evgeny Stupachenko <email@example.com>
>> * config/i386/i386.c (ix86_have_vector_parallel_execution): New.
>> (TARGET_VECTORIZE_HAVE_VECTOR_PARALLEL_EXECUTION): New.
>> * config/i386/i386.h (TARGET_VECTOR_PARALLEL_EXECUTION): New.
>> * config/i386/x86-tune.def (X86_TUNE_VECTOR_PARALLEL_EXECUTION): New.
>> * target.def (have_vector_parallel_execution): New.
>> * doc/tm.texi.in (have_vector_parallel_execution)): New.
>> * doc/tm.texi: Regenerate.
>> * targhooks.c (default_have_vector_parallel_execution): New.
>> * tree-vect-data-refs.c (vect_shift_permute_load_chain): New.
>> Introduces alternative way of loads group permutaions.
>> (vect_transform_grouped_load): Try alternative way of permutaions.