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

[Hongtao Yu via Phabricator via llvm-commits]

hoy added a comment.

In D149597#4328418 <https://reviews.llvm.org/D149597#4328418>, @wenlei wrote:

>> I was seeing a regression when enabling FS discriminators on an non-FS CSSPGO build. This is because a probe can get a zero-valued discriminator at a specific pass and that could lead to accidentally loading the corresponding base counter in the non-FS profile
>
> For non-FS profile, probe doesn't have discriminator, is there no way to differentiate zero discriminator from no discriminator? If a probe in the profile doesn't have discriminator, it should not be considered for FS profile loading. In this case, if input profile is not FS, no probe would have discriminator, hence nothing should be loaded in MIR. Is such checking missing on per-probe level?

The body sample map uses id+discriminator as the key, so currently we don't have a way on the function level to tell if a function profile is FS or not. We can tell on the program level, basically using the FS flag.


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