[PATCH] D108087: [SimpleLoopUnswitch] Create SimpleLoopNestUnswitch pass
Whitney Tsang via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 24 11:21:53 PDT 2021
Whitney added inline comments.
================
Comment at: llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp:2973
+ Instruction *BestUnswitchTI =
+ findBestUnswitchTI(L, DT, LI, AC, AA, TTI, SE, MSSAU, PartialIVInfo,
+ ExitBlocks, BestUnswitchInvariants);
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When given BestUnswitchTIForLoopNest, why do we want to findBestUnswitchTI?
When given BestUnswitchTIForLoopNest, this code only unswitch if BestUnswitchTIForLoopNest == findBestUnswitchTI. Is it possible that BestUnswitchTIForLoopNest != findBestUnswitchTI only have some loop level?
================
Comment at: llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp:2976
+
+ if (BestUnswitchTI == nullptr)
+ return false;
----------------
================
Comment at: llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp:2982
+ // unswitching.
+ if (BestUnswitchTIForLoopNest != nullptr &&
+ BestUnswitchTI != BestUnswitchTIForLoopNest)
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CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D108087/new/
https://reviews.llvm.org/D108087
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