[llvm-dev] Reversion of rL292621 caused about 7% performance regressions on Cortex-M

[Wei Mi via llvm-dev]

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
>>> >
>>> >