[PATCH] D43520: [ThinLTO] Represent relative BF using a scaled representation .
David Li via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 20 13:20:57 PST 2018
davidxl added inline comments.
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Comment at: include/llvm/IR/ModuleSummaryIndex.h:63
uint32_t Hotness : 3;
uint32_t RelBlockFreq : 29;
+ static constexpr int32_t ScaleShift = 8;
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Document that it is RelativeBlockFrequency scaled by 2^8
Also should all the uses of RelBlockFreq scale it back?
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Comment at: include/llvm/IR/ModuleSummaryIndex.h:65
+ static constexpr int32_t ScaleShift = 8;
static constexpr uint64_t MaxRelBlockFreq = (1 << 29) - 1;
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Should this be scaled up too?
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Comment at: include/llvm/IR/ModuleSummaryIndex.h:86
+ Scaled64 Temp(BlockFreq, ScaleShift);
+ Temp /= Scaled64::get(EntryFreq);
+
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EntryFreq can be zero.
Repository:
rL LLVM
https://reviews.llvm.org/D43520
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