llvm dev - Jan 2017 - Reversion of rL292621 caused about 7% performance regressions on Cortex-M

Hi Wei,

Thank you for information.
Please let me know about any progress in fixing the failures.
I can help with checking that the final patch gives the same level of
performance improvements.

Kind regards,
Evgeny Astigeevich
Senior Compiler Engineer
Compilation Tools
ARM
 
> -----Original Message-----
> From: Wei Mi [mailto:wmi at google.com]
> Sent: Friday, January 27, 2017 6:20 PM
> To: Evgeny Astigeevich
> Cc: llvm-dev; nd
> Subject: Re: Reversion of rL292621 caused about 7% performance
> regressions on Cortex-M
> 
> Hi Evgeny,
> 
> The failure is a compiler crash on an out-of-tree target in apple.
> Quentin is helping to find a reproducible but havn't succeeded yet.
> Once I get a reproducible, I will fix it. Thanks for the interest on the
work.
> Details about the crash can be found here:
> http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-
> 20170123/422853.html
> 
> Thanks,
> Wei.
> 
> 
> On Fri, Jan 27, 2017 at 10:11 AM, Evgeny Astigeevich
> <Evgeny.Astigeevich at arm.com> wrote:
> > Hi Wei,
> >
> >
> >
> > Your reversion of rL292621 caused about 7% performance regressions in
> > our benchmark on Cortex-M7/M4.
> >
> > In your commit comment I see it causes build bot failures.
> >
> > What kind are the failures? Compiler crashes or incorrect code
generation?
> > Will you fix them?
> >
> > We are interested in the changes because of performance improvements
> > they give.
> >
> >
> >
> > Kind regards,
> >
> > Evgeny Astigeevich
> >
> > Senior Compiler Engineer
> > Compilation Tools
> > ARM
> >
> >

Sure. Will keep you posted.

Thanks,
Wei.

On Fri, Jan 27, 2017 at 10:31 AM, Evgeny Astigeevich
<Evgeny.Astigeevich at arm.com> wrote:
> Hi Wei,
>
> Thank you for information.
> Please let me know about any progress in fixing the failures.
> I can help with checking that the final patch gives the same level of
performance improvements.
>
> Kind regards,
> Evgeny Astigeevich
> Senior Compiler Engineer
> Compilation Tools
> ARM
>
>
>> -----Original Message-----
>> From: Wei Mi [mailto:wmi at google.com]
>> Sent: Friday, January 27, 2017 6:20 PM
>> To: Evgeny Astigeevich
>> Cc: llvm-dev; nd
>> Subject: Re: Reversion of rL292621 caused about 7% performance
>> regressions on Cortex-M
>>
>> Hi Evgeny,
>>
>> The failure is a compiler crash on an out-of-tree target in apple.
>> Quentin is helping to find a reproducible but havn't succeeded yet.
>> Once I get a reproducible, I will fix it. Thanks for the interest on
the work.
>> Details about the crash can be found here:
>> http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-
>> 20170123/422853.html
>>
>> Thanks,
>> Wei.
>>
>>
>> On Fri, Jan 27, 2017 at 10:11 AM, Evgeny Astigeevich
>> <Evgeny.Astigeevich at arm.com> wrote:
>> > Hi Wei,
>> >
>> >
>> >
>> > Your reversion of rL292621 caused about 7% performance regressions
in
>> > our benchmark on Cortex-M7/M4.
>> >
>> > In your commit comment I see it causes build bot failures.
>> >
>> > What kind are the failures? Compiler crashes or incorrect code
generation?
>> > Will you fix them?
>> >
>> > We are interested in the changes because of performance
improvements
>> > they give.
>> >
>> >
>> >
>> > Kind regards,
>> >
>> > Evgeny Astigeevich
>> >
>> > Senior Compiler Engineer
>> > Compilation Tools
>> > ARM
>> >
>> >

Hi Evgeny,

Quentin and Matthias found it was a problem about subreg live range
update and will push a fix soon
(http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20170123/424126.html).

Thanks,
Wei.

On Fri, Jan 27, 2017 at 10:35 AM, Wei Mi <wmi at google.com>
wrote:
> Sure. Will keep you posted.
>
> Thanks,
> Wei.
>
> On Fri, Jan 27, 2017 at 10:31 AM, Evgeny Astigeevich
> <Evgeny.Astigeevich at arm.com> wrote:
>> Hi Wei,
>>
>> Thank you for information.
>> Please let me know about any progress in fixing the failures.
>> I can help with checking that the final patch gives the same level of
performance improvements.
>>
>> Kind regards,
>> Evgeny Astigeevich
>> Senior Compiler Engineer
>> Compilation Tools
>> ARM
>>
>>
>>> -----Original Message-----
>>> From: Wei Mi [mailto:wmi at google.com]
>>> Sent: Friday, January 27, 2017 6:20 PM
>>> To: Evgeny Astigeevich
>>> Cc: llvm-dev; nd
>>> Subject: Re: Reversion of rL292621 caused about 7% performance
>>> regressions on Cortex-M
>>>
>>> Hi Evgeny,
>>>
>>> The failure is a compiler crash on an out-of-tree target in apple.
>>> Quentin is helping to find a reproducible but havn't succeeded
yet.
>>> Once I get a reproducible, I will fix it. Thanks for the interest
on the work.
>>> Details about the crash can be found here:
>>> http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-
>>> 20170123/422853.html
>>>
>>> Thanks,
>>> Wei.
>>>
>>>
>>> On Fri, Jan 27, 2017 at 10:11 AM, Evgeny Astigeevich
>>> <Evgeny.Astigeevich at arm.com> wrote:
>>> > Hi Wei,
>>> >
>>> >
>>> >
>>> > Your reversion of rL292621 caused about 7% performance
regressions in
>>> > our benchmark on Cortex-M7/M4.
>>> >
>>> > In your commit comment I see it causes build bot failures.
>>> >
>>> > What kind are the failures? Compiler crashes or incorrect code
generation?
>>> > Will you fix them?
>>> >
>>> > We are interested in the changes because of performance
improvements
>>> > they give.
>>> >
>>> >
>>> >
>>> > Kind regards,
>>> >
>>> > Evgeny Astigeevich
>>> >
>>> > Senior Compiler Engineer
>>> > Compilation Tools
>>> > ARM
>>> >
>>> >