[RFC] Speed-up -fprofile-update=atomic

Richard Biener richard.guenther@gmail.com
Wed Oct 26 09:29:00 GMT 2016


On Tue, Oct 25, 2016 at 4:31 PM, Martin Liška <mliska@suse.cz> wrote:
> On 10/24/2016 03:51 PM, Richard Biener wrote:
>
>> It's quite ad-hoc :/  The IFN will also be a memory optimization
>> barrier unless you add special support
>> for it in the alias oracle - so the performance measurement needs to
>> be taken with a grain of salt
>> (same is true for all atomics of course... - I have some local patches
>> to improve things here).
>
> Good, thus please ping me with the patches you have and I'll integrate it.
>
>>
>> The way you implement process_sm_for_coverage_counter is more like a
>> final value replacement.
>> You could maybe use create_iv for the loop counter or even wind up
>> computing the final value
>> (number of iterations) only after the loop, avoiding the IV completely
>> (eventually SCEV cprop
>> saves you here afterwards).
>
> Or maybe we can basically assign loop->niter as the argument of UPDATE_COVERAGE_COUNTER
> function?

Yes, that's what I said.

Richard.

> Martin
>
>>
>> Richard.
>



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