[LLVMdev] [RFC] AArch64: Should we disable GlobalMerge?

Jim Grosbach
2015-02-27T23:06:01Z

> On Feb 27, 2015, at 2:15 PM, Ahmed Bougacha <ahmed.bougacha at
gmail.com> wrote:
>
> On Fri, Feb 27, 2015 at 2:01 PM, Renato Golin <renato.golin at
linaro.org> wrote:
>> On 27 February 2015 at 21:26, Ahmed Bougacha <ahmed.bougacha at
gmail.com> wrote:
>>> Which brings us to my fallback proposal:  what about disabling the
>>> pass on darwin only?
>>
>> That's a decision for Jim/Evan. I'm ok if they are.
>
> Jim, thoughts?

I would prefer Darwin not differ in this regard, but I don’t feel incredibly
strongly about it. Just a general preference to keeping platform dependencies
and differences to a minimum. Whatever y’all decide is fine with me.

>
>>
>>> As for other targets, as a first step, making the pass run under
-O3
>>> rather than -O1 is hopefully agreeable to everyone?
>>
>> Sounds reasonable.
>
> Great!
>
>> Even though it conflicts with LTO, that's what O3 means, as you
said,
>> instability. People at O3 might want to fiddle with the passes
>> (on/off) to get the best performance for their own code/workload.
>
> By the way, I'm not convinced LTO being either -O3 or -O0 is sensible.
> But that's a discussion for another day =)
>
> -Ahmed
>
>> cheers,
>> --renato