[PATCH] D71990: [LoopUtils] Better accuracy for getLoopEstimatedTripCount.

[Ayal Zaks via Phabricator via llvm-commits]

Ayal added inline comments.


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Comment at: llvm/lib/Transforms/Utils/LoopUtils.cpp:726
   if (!LatchCycleWeight || !LatchExitWeight)
     return 0;
 
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If !LatchCycleWeight (if !BackedgeTakenWeight) it should return 1 instead of 0. I.e., should always be equal to "getEstimateBackedgeTakenCount()" plus 1.

If !LatchExitWeight, perhaps better return None instead of 0? This implies the loop was never entered when gathering the profile, or loop was entered once and never exited(?); in either case estimating the trip count to be zero seems wrong.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71990/new/

https://reviews.llvm.org/D71990