[PATCH] D36052: Update the new PM pipeline to make ICP aware if it is SamplePGO build.

[Dehao Chen via llvm-commits]

On Sat, Jul 29, 2017 at 5:12 PM, Xinliang David Li <davidxl at google.com>
wrote:

>
>
> On Sat, Jul 29, 2017 at 4:39 PM, Dehao Chen via Phabricator <
> reviews at reviews.llvm.org> wrote:
>
>> danielcdh added a comment.
>>
>> In https://reviews.llvm.org/D36052#825318, @davidxl wrote:
>>
>> > Instr PGO has its own set of simplification passes, but still I think
>> we should keep this patch NFC for instrPGO. If there are performance
>> numbers that justify the InstrPGO pipeline changes, it can be
>> discussed/done in a separate thread.  This one should be left as SamplePGO
>> only change.
>>
>>
>> The tricky part is that PGOOptions was not passed in the ThinLTO backend
>> before this patch. But after this patch, it will be passed in. However, in
>> buildModuleSimplificationPipeline, it cannot know if this is the ThinLTO
>> backend. As a result, we cannot disable instrumentation/annotation pass in
>> there.
>>
>> The potential solution could be:
>>
>> - add another boolean value in buildModuleSimplificationPipeline to
>> indicate it's ThinLTO backend
>> - refactor the code from the beginning of buildModuleSimplificationPipeline
>> to the PGOOpt handling to a separate function, and call it separately in
>> the caller of buildModuleSimplificationPipeline.
>>
>
>
> If there is no good logical separation to split the
> buildModuleSimplificationPipeline, it is better to go with option #1.
>

Chandler, could you sched some lights (I'm asking because Chandler may not
want to introduce another flag as suggested in the review of
https://reviews.llvm.org/D36040)

I think we should at least have a separate effort to make EarlyFPM not
invoked by ThinLTO backend to match the legacy PM's behavior.

Thanks,
Dehao



>
> David
>
>
>>
>> Any suggestions on how to move forward?
>>
>> Thanks,
>> Dehao
>>
>>
>> https://reviews.llvm.org/D36052
>>
>>
>>
>>
>
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