[PATCH] D120231: [SelectOpti][3/5] Base Heuristics

[David Li via Phabricator via llvm-commits]

davidxl added inline comments.


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Comment at: llvm/lib/CodeGen/SelectOptimize.cpp:451
+      for (auto *ColdII : ColdSlice) {
+        SliceCost +=
+            TTI->getInstructionCost(ColdII, TargetTransformInfo::TCK_Latency);
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Should the cost also consider the frequency difference between the SI and the cold operand?

basically the colder the operand, the more expensive it is to use CMOV.


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Comment at: llvm/lib/CodeGen/SelectOptimize.cpp:453
+            TTI->getInstructionCost(ColdII, TargetTransformInfo::TCK_Latency);
+        if (SliceCost >= TargetTransformInfo::TCC_Expensive)
+          return true;
----------------
Suggest adding an option which is the multiplier of the TCC_expensive


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D120231/new/

https://reviews.llvm.org/D120231