[PATCH] D149597: [FS-AFDO] Do not load non-FS profile in MIR loader.

[Wenlei He via Phabricator via llvm-commits]

wenlei accepted this revision.
wenlei added a comment.
This revision is now accepted and ready to land.

In D149597#4333318 <https://reviews.llvm.org/D149597#4333318>, @hoy wrote:

> In D149597#4333284 <https://reviews.llvm.org/D149597#4333284>, @wenlei wrote:
>
>>> However for lines that do have a zero FSdiscriminator, line+FSdiscriminator can accidentally match the base counter while all other lines still load nothing.
>>
>> Can this also happen when input profile is actually a FS profile? which is also not good? Or is that less of a problem when input profile is FS because we will also load other samples whose FSDiscriminator is non-zero?
>
> I think it's not a problem for FS profiles. Given a FS profile, a zero discriminator is a valid FS discriminator which means the counter is not aggregated and there will be no more than one line loading that counter on MIR. For a non-FS profile, we cannot tell if a zero is a valid FS discriminator unless the file-level flag is checked.

ok, that makes sense since profile reader actually masks discriminator based on the current FSDiscriminator mask.


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https://reviews.llvm.org/D149597