Author: Chen Zheng Date: 2020-12-01T22:29:33-05:00 New Revision: 3cb7d6245249d61f443abfacc6d7b0272a71535e
URL: https://github.com/llvm/llvm-project/commit/3cb7d6245249d61f443abfacc6d7b0272a71535e DIFF: https://github.com/llvm/llvm-project/commit/3cb7d6245249d61f443abfacc6d7b0272a71535e.diff LOG: [LSR][NFC] don't collect chains when isNumRegsMajorCostOfLSR is false. Reviewed By: samparker Differential Revision: https://reviews.llvm.org/D92159 Added: Modified: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp Removed: ################################################################################ diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp index a1d182931d0f..bfd8f00c228e 100644 --- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -2858,20 +2858,12 @@ static bool isProfitableChain(IVChain &Chain, unsigned NumVarIncrements = 0; unsigned NumReusedIncrements = 0; - // If any LSRUse in the chain is marked as profitable by target, mark this - // chain as profitable. - for (const IVInc &Inc : Chain.Incs) - if (TTI.isProfitableLSRChainElement(Inc.UserInst)) - return true; - - // If number of registers is not the major cost, we cannot benefit from this - // profitable chain which is based on number of registers. - // FIXME: add profitable chain optimization for other kinds major cost, for - // example number of instructions. - if (!TTI.isNumRegsMajorCostOfLSR()) - return false; + if (TTI.isProfitableLSRChainElement(Chain.Incs[0].UserInst)) + return true; for (const IVInc &Inc : Chain) { + if (TTI.isProfitableLSRChainElement(Inc.UserInst)) + return true; if (Inc.IncExpr->isZero()) continue; @@ -5635,7 +5627,13 @@ LSRInstance::LSRInstance(Loop *L, IVUsers &IU, ScalarEvolution &SE, } // Start collecting data and preparing for the solver. - CollectChains(); + // If number of registers is not the major cost, we cannot benefit from the + // current profitable chain optimization which is based on number of + // registers. + // FIXME: add profitable chain optimization for other kinds major cost, for + // example number of instructions. + if (TTI.isNumRegsMajorCostOfLSR() || StressIVChain) + CollectChains(); CollectInterestingTypesAndFactors(); CollectFixupsAndInitialFormulae(); CollectLoopInvariantFixupsAndFormulae(); _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
