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Re: [PATCH GCC][5/5]Enable tree loop distribution at -O3 and above optimization levels.


On Mon, Aug 7, 2017 at 11:10 AM, Bin.Cheng <amker.cheng@gmail.com> wrote:
> On Fri, Jun 23, 2017 at 12:04 PM, Richard Biener
> <richard.guenther@gmail.com> wrote:
>> On Fri, Jun 23, 2017 at 10:47 AM, Bin.Cheng <amker.cheng@gmail.com> wrote:
>>> On Fri, Jun 23, 2017 at 6:04 AM, Jeff Law <law@redhat.com> wrote:
>>>> On 06/07/2017 02:07 AM, Bin.Cheng wrote:
>>>>> On Tue, Jun 6, 2017 at 6:47 PM, Jeff Law <law@redhat.com> wrote:
>>>>>> On 06/02/2017 05:52 AM, Bin Cheng wrote:
>>>>>>> Hi,
>>>>>>> This patch enables -ftree-loop-distribution by default at -O3 and above optimization levels.
>>>>>>> Bootstrap and test at O2/O3 on x86_64 and AArch64.  is it OK?
>>>>>>>
>>>>>>> Note I don't have strong opinion here and am fine with either it's accepted or rejected.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> bin
>>>>>>> 2017-05-31  Bin Cheng  <bin.cheng@arm.com>
>>>>>>>
>>>>>>>       * opts.c (default_options_table): Enable OPT_ftree_loop_distribution
>>>>>>>       for -O3 and above levels.
>>>>>> I think the question is how does this generally impact the performance
>>>>>> of the generated code and to a lesser degree compile-time.
>>>>>>
>>>>>> Do you have any performance data?
>>>>> Hi Jeff,
>>>>> At this stage of the patch, only hmmer is impacted and improved
>>>>> obviously in my local run of spec2006 for x86_64 and AArch64.  In long
>>>>> term, loop distribution is also one prerequisite transformation to
>>>>> handle bwaves (at least).  For these two impacted cases, it helps to
>>>>> resolve the gap against ICC.  I didn't check compilation time slow
>>>>> down, we can restrict it to problem with small partition number if
>>>>> that's a problem.
>>>> Just a note. I know you've iterated further with Richi -- I'm not
>>>> objecting to the patch, nor was I ready to approve.
>>>>
>>>> Are you and Richi happy with this as-is or are you looking to submit
>>>> something newer based on the conversation the two of you have had?
>>> Hi Jeff,
>>> The patch series is updated in various ways according to review
>>> comments, for example, it restricts compilation time by checking
>>> number of data references against MAX_DATAREFS_FOR_DATADEPS as well as
>>> restores data dependence cache.  There are still two missing parts I'd
>>> like to do as followup patches: one is loop nest distribution and the
>>> other is a data-locality cost model (at least) for small cases.  Now
>>> Richi approved most patches except the last major one, but I still
>>> need another iterate for some (approved) patches in order to fix
>>> mistake/typo introduced when I separating the patch.
>>
>> The patch is ok after the approved parts of the ldist series has been committed.
>> Note your patch lacks updates to invoke.texi (what options are enabled at -O3).
>> Please adjust that before committing.
> Hi All,
> Given the loop distribution patches have been merged for a while and
> couple of issues fixed.  I am submitting updated patch to enable the
> pass by default at O3/above levels.
> Bootstrap and test on x86_64 and AArch64 ongoing.  Hmmer still can be
> improved.  Is it OK if no failure?

Ok.

Thanks,
Richard.

> Thanks,
> bin
> 2017-08-07  Bin Cheng  <bin.cheng@arm.com>
>
>     * doc/invoke.texi: Document -ftree-loop-distribution for O3.
>     * opts.c (default_options_table): Add OPT_ftree_loop_distribution.


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