[PATCH] D86156: [BFI] Preserve BFI information through loop passes via VH callbacks inside LoopStandardAnalysisResults

Thu Aug 27 18:23:46 PDT 2020

wenlei added a comment.

In D86156#2243393 <https://reviews.llvm.org/D86156#2243393>, @asbirlea wrote:

> Diff looks reasonable at this point. Thank you for the patch!
> Please wait on @nikic for compile-time impact or additional feedback.
>
> Just out of curiosity, in D65060 <https://reviews.llvm.org/D65060>, it was mentioned that using BFI got you ~7% improvement for a CPU related metric (@wenlei). Are you seeing benefits from this patch? And which pass manager are you using?

Thanks for quick review. We got the perf improvement from preventing a bad hoisting in a critical loop using BFI. Originally it was with legacy pass manager, hence the invalidation issue with new pass manager wasn't caught from our usage. This change was made as an internal patch for perf parity when we moved to new pass manager, and we've been using it for a while now.

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