[PATCH] D124481: [llvm][misexpect] Add tests for sample profiling

Tue May 24 07:38:11 PDT 2022

tejohnson added a comment.

In D124481#3532977 <https://reviews.llvm.org/D124481#3532977>, @paulkirth wrote:

> @tejohnson I have a test case that encapsulates when SampleProfiling crashes we saw w/ misexpect a while ago.

Won't this patch if committed trigger the failure again?

> What I've been trying to figure out is how a profile ever gets zero weights like this.

Can you use the original failing test case to dig into this more? Looks like it was XFDO from the internal Google bug. Reach out to me internally if you need help reproducing that.

> My understanding of the PGO pipeline is that there are 3 modes where profiling weights are added: Front End Instrumentation inserted by clang, IR profiles, and SampleProfiling. My understanding was also that these modes were incompatible with one another, so you wouldn't have weights added by multiple sources, e.g., IR //and// Sample Profiling.

I believe it is possible to combine IR and SamplePGO profiles, but it doesn't look like that is the case in the failing test case.

Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D124481