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

[Evgeny Astigeevich via llvm-dev]

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
> >
> >