Disable arm-gepopt by default

[Michael Zolotukhin]

Hi Tim and others,

So, the entire discussion is moving around the assumption that this pass is beneficial in some cases, but we don’t have such data. Please note that I don’t want to say that the assumption is wrong, but as far as I understand, only Hao observed some gains. Thus, until we hear from him, we have real slow downs versus presumable gains.

As for the looking into the code later - I’m not an expert in this area, and I don’t even have a motivational example for this optimization, so I’d barely be a right person for it. I’d be glad to assist with collecting some additional data/running tests if that might help though.

Thanks,
Michael


> On Apr 20, 2015, at 8:40 PM, Tim Northover <t.p.northover at gmail.com> wrote:
> 
> On 20 April 2015 at 20:34, Gerolf Hoflehner <ghoflehner at apple.com> wrote:
>> It shouldn’t come across as ‘extreme’.
> 
> The "extreme" part wasn't so much the tentative disabling as "Could
> you and/or Hao take this on after the code is disabled/backed out?". I
> realise it wasn't an ultimatum, but it could very easily turn into
> "we're washing our hands of this", which I'd object to.
> 
> I assume the pass was committed with some kind of metric that it
> improved, and now we have a counter-example. It's down to everyone to
> decide what the best way to proceed is.
> 
> Cheers.
> 
> Tim.
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits