From 807dad62a0d4f1a1bbcb76fdc447634f76308252 Mon Sep 17 00:00:00 2001 From: Nadav Rotem Date: Thu, 13 Dec 2012 00:21:03 +0000 Subject: Teach the cost model about the optimization in r169904: Truncation of induction variables costs the same as scalar trunc. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170051 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Vectorize/LoopVectorize.cpp | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) (limited to 'lib/Transforms/Vectorize/LoopVectorize.cpp') diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp index cdd130f135..475bea1485 100644 --- a/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -106,8 +106,7 @@ struct LoopVectorize : public LoopPass { } DEBUG(dbgs() << "LV: Found a vectorizable loop ("<< VF << ") in "<< - L->getHeader()->getParent()->getParent()->getModuleIdentifier()<< - "\n"); + F->getParent()->getModuleIdentifier()<<"\n"); // If we decided that it is *legal* to vectorizer the loop then do it. InnerLoopVectorizer LB(L, SE, LI, DT, DL, VF); @@ -1849,6 +1848,15 @@ LoopVectorizationLegality::isInductionVariable(PHINode *Phi) { return NoInduction; } +bool LoopVectorizationLegality::isInductionVariable(const Value *V) { + Value *In0 = const_cast(V); + PHINode *PN = dyn_cast_or_null(In0); + if (!PN) + return false; + + return Inductions.count(PN); +} + bool LoopVectorizationLegality::blockNeedsPredication(BasicBlock *BB) { assert(TheLoop->contains(BB) && "Unknown block used"); @@ -2110,6 +2118,13 @@ LoopVectorizationCostModel::getInstructionCost(Instruction *I, unsigned VF) { case Instruction::Trunc: case Instruction::FPTrunc: case Instruction::BitCast: { + // We optimize the truncation of induction variable. + // The cost of these is the same as the scalar operation. + if (I->getOpcode() == Instruction::Trunc && + Legal->isInductionVariable(I->getOperand(0))) + return VTTI->getCastInstrCost(I->getOpcode(), I->getType(), + I->getOperand(0)->getType()); + Type *SrcVecTy = ToVectorTy(I->getOperand(0)->getType(), VF); return VTTI->getCastInstrCost(I->getOpcode(), VectorTy, SrcVecTy); } -- cgit v1.2.3-18-g5258