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Re: AutoFDO profile toolchain is open-sourced


On Mon, Apr 27, 2015 at 7:37 AM, Ilya Palachev <i.palachev@samsung.com> wrote:
> Hi,
>
> On 21.04.2015 20:25, Dehao Chen wrote:
>>
>> OTOH, the most important patch (insn-level discriminator support) is
>> not in yet. Cary has just retired. Do you know if anyone would be
>> interested in porting insn-level discriminator support to trunk?
>
>
> Do you mean r210338, r210397, r210523, r214745 ?

Yes

> Can you explain why these patches are important for autofdo?

Instruction level discriminator support is important to autofdo
because basic block level discriminator is not enough when
instructions are moved to other basic blocks by code motion.
Additionally, gcc backend optimization does not maintain BB level
discriminator well. We need to encode discriminator as part of LOC so
that once the discriminator is assigned to an IR, it will go all the
way to the codegen without being modified.

> What work should be done to port them to current 5 branch?

I think we just need to have these patches in. Or even better,
reimplement this the same way as my lexical block patch
(https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=191494)

> Do you expect them to be applied to 6 branch?

This should go into trunk and be there for all later gcc branches.

Dehao

>
> --
> Ilya


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