[PATCH] D57805: [HotColdSplit] Move splitting after instrumented PGO use

[Vedant Kumar via Phabricator via llvm-commits]

vsk added a comment.

@tejohnson have you had a chance to evaluate performance with IR-PGO + splitting enabled?

Our internal CI shows performance regressions on SPEC/CINT2000 with FE-PGO + splitting enabled. Allowing inlining of split functions reduces the perf regression, and moving splitting after inlining eliminates it. It seems important to inline and optimize certain basic blocks which FE PGO data marks cold. We may need to address this by changing the FE-PGO instrumentation, or by ignoring ProfileSummaryInfo when it's based on a FE profile.

What's interesting about this is that I didn't see a perf regression on SPEC/CINT2000 with IR-PGO + splitting. I'd be curious to know if your testing bears this out.


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  rL LLVM

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https://reviews.llvm.org/D57805