From d15c0c7ac118cb23241b002e7206221283e36e2d Mon Sep 17 00:00:00 2001 From: Nadav Rotem Date: Wed, 17 Oct 2012 18:25:06 +0000 Subject: Add a loop vectorizer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166112 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/InitializePasses.h | 1 + include/llvm/LinkAllPasses.h | 1 + include/llvm/Transforms/Vectorize.h | 6 + lib/Transforms/IPO/PassManagerBuilder.cpp | 6 + lib/Transforms/Vectorize/CMakeLists.txt | 1 + lib/Transforms/Vectorize/LoopVectorize.cpp | 801 ++++++++++++++++++++++++++ lib/Transforms/Vectorize/Vectorize.cpp | 8 +- test/Transforms/LoopVectorize/gcc-examples.ll | 651 +++++++++++++++++++++ test/Transforms/LoopVectorize/lit.local.cfg | 1 + test/Transforms/LoopVectorize/non-const-n.ll | 38 ++ 10 files changed, 1512 insertions(+), 2 deletions(-) create mode 100644 lib/Transforms/Vectorize/LoopVectorize.cpp create mode 100644 test/Transforms/LoopVectorize/gcc-examples.ll create mode 100644 test/Transforms/LoopVectorize/lit.local.cfg create mode 100644 test/Transforms/LoopVectorize/non-const-n.ll diff --git a/include/llvm/InitializePasses.h b/include/llvm/InitializePasses.h index ee9b1c5852e..1fb9218ba12 100644 --- a/include/llvm/InitializePasses.h +++ b/include/llvm/InitializePasses.h @@ -261,6 +261,7 @@ void initializeVirtRegRewriterPass(PassRegistry&); void initializeInstSimplifierPass(PassRegistry&); void initializeUnpackMachineBundlesPass(PassRegistry&); void initializeFinalizeMachineBundlesPass(PassRegistry&); +void initializeLoopVectorizePass(PassRegistry&); void initializeBBVectorizePass(PassRegistry&); void initializeMachineFunctionPrinterPassPass(PassRegistry&); } diff --git a/include/llvm/LinkAllPasses.h b/include/llvm/LinkAllPasses.h index 4b10d0e5415..8652acd941f 100644 --- a/include/llvm/LinkAllPasses.h +++ b/include/llvm/LinkAllPasses.h @@ -156,6 +156,7 @@ namespace { (void) llvm::createCorrelatedValuePropagationPass(); (void) llvm::createMemDepPrinter(); (void) llvm::createInstructionSimplifierPass(); + (void) llvm::createLoopVectorizePass(); (void) llvm::createBBVectorizePass(); (void)new llvm::IntervalPartition(); diff --git a/include/llvm/Transforms/Vectorize.h b/include/llvm/Transforms/Vectorize.h index 1e49a9c01e6..41e53a83e2f 100644 --- a/include/llvm/Transforms/Vectorize.h +++ b/include/llvm/Transforms/Vectorize.h @@ -106,6 +106,12 @@ struct VectorizeConfig { BasicBlockPass * createBBVectorizePass(const VectorizeConfig &C = VectorizeConfig()); +//===----------------------------------------------------------------------===// +// +// LoopVectorize - Create a loop vectorization pass. +// +Pass * createLoopVectorizePass(); + //===----------------------------------------------------------------------===// /// @brief Vectorize the BasicBlock. /// diff --git a/lib/Transforms/IPO/PassManagerBuilder.cpp b/lib/Transforms/IPO/PassManagerBuilder.cpp index a2862022a3b..97698caa516 100644 --- a/lib/Transforms/IPO/PassManagerBuilder.cpp +++ b/lib/Transforms/IPO/PassManagerBuilder.cpp @@ -176,6 +176,12 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) { MPM.add(createIndVarSimplifyPass()); // Canonicalize indvars MPM.add(createLoopIdiomPass()); // Recognize idioms like memset. MPM.add(createLoopDeletionPass()); // Delete dead loops + + if (Vectorize) { + MPM.add(createLoopVectorizePass()); + MPM.add(createLICMPass()); + } + if (!DisableUnrollLoops) MPM.add(createLoopUnrollPass()); // Unroll small loops addExtensionsToPM(EP_LoopOptimizerEnd, MPM); diff --git a/lib/Transforms/Vectorize/CMakeLists.txt b/lib/Transforms/Vectorize/CMakeLists.txt index 06cf1e4e532..e64034ab26b 100644 --- a/lib/Transforms/Vectorize/CMakeLists.txt +++ b/lib/Transforms/Vectorize/CMakeLists.txt @@ -1,6 +1,7 @@ add_llvm_library(LLVMVectorize BBVectorize.cpp Vectorize.cpp + LoopVectorize.cpp ) add_dependencies(LLVMVectorize intrinsics_gen) diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp new file mode 100644 index 00000000000..60405e7f9f6 --- /dev/null +++ b/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -0,0 +1,801 @@ +//===- LoopVectorize.cpp - A Loop Vectorizer ------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This is a simple loop vectorizer. We currently only support single block +// loops. We have a very simple and restrictive legality check: we need to read +// and write from disjoint memory locations. We still don't have a cost model. +// This pass has three parts: +// 1. The main loop pass that drives the different parts. +// 2. LoopVectorizationLegality - A helper class that checks for the legality +// of the vectorization. +// 3. SingleBlockLoopVectorizer - A helper class that performs the actual +// widening of instructions. +// +//===----------------------------------------------------------------------===// +#define LV_NAME "loop-vectorize" +#define DEBUG_TYPE LV_NAME +#include "llvm/Constants.h" +#include "llvm/DerivedTypes.h" +#include "llvm/Instructions.h" +#include "llvm/LLVMContext.h" +#include "llvm/Pass.h" +#include "llvm/Analysis/LoopPass.h" +#include "llvm/Value.h" +#include "llvm/Function.h" +#include "llvm/Module.h" +#include "llvm/Type.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/StringExtras.h" +#include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/Analysis/AliasSetTracker.h" +#include "llvm/Transforms/Scalar.h" +#include "llvm/Analysis/ScalarEvolution.h" +#include "llvm/Analysis/ScalarEvolutionExpressions.h" +#include "llvm/Analysis/ScalarEvolutionExpander.h" +#include "llvm/Transforms/Utils/BasicBlockUtils.h" +#include "llvm/Analysis/ValueTracking.h" +#include "llvm/Analysis/LoopInfo.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/DataLayout.h" +#include "llvm/Transforms/Utils/Local.h" +#include +using namespace llvm; + +static cl::opt +DefaultVectorizationFactor("default-loop-vectorize-width", + cl::init(4), cl::Hidden, + cl::desc("Set the default loop vectorization width")); + +namespace { + +/// Vectorize a simple loop. This class performs the widening of simple single +/// basic block loops into vectors. It does not perform any +/// vectorization-legality checks, and just does it. It widens the vectors +/// to a given vectorization factor (VF). +class SingleBlockLoopVectorizer { +public: + + /// Ctor. + SingleBlockLoopVectorizer(Loop *OrigLoop, ScalarEvolution *Se, LoopInfo *Li, + unsigned VecWidth): + Orig(OrigLoop), SE(Se), LI(Li), VF(VecWidth), + Builder(0), Induction(0), OldInduction(0) { } + + ~SingleBlockLoopVectorizer() { + delete Builder; + } + + // Perform the actual loop widening (vectorization). + void vectorize() { + ///Create a new empty loop. Unlink the old loop and connect the new one. + copyEmptyLoop(); + /// Widen each instruction in the old loop to a new one in the new loop. + vectorizeLoop(); + // Delete the old loop. + deleteOldLoop(); + } + +private: + /// Create an empty loop, based on the loop ranges of the old loop. + void copyEmptyLoop(); + /// Copy and widen the instructions from the old loop. + void vectorizeLoop(); + /// Delete the old loop. + void deleteOldLoop(); + + /// This instruction is un-vectorizable. Implement it as a sequence + /// of scalars. + void scalarizeInstruction(Instruction *Instr); + + /// Create a broadcast instruction. This method generates a broadcast + /// instruction (shuffle) for loop invariant values and for the induction + /// value. If this is the induction variable then we extend it to N, N+1, ... + /// this is needed because each iteration in the loop corresponds to a SIMD + /// element. + Value *getBroadcastInstrs(Value *V); + + /// This is a helper function used by getBroadcastInstrs. It adds 0, 1, 2 .. + /// for each element in the vector. Starting from zero. + Value *getConsecutiveVector(Value* Val); + + /// Check that the GEP operands are all uniform except for the last index + /// which has to be the induction variable. + bool isConsecutiveGep(GetElementPtrInst *Gep); + + /// When we go over instructions in the basic block we rely on previous + /// values within the current basic block or on loop invariant values. + /// When we widen (vectorize) values we place them in the map. If the values + /// are not within the map, they have to be loop invariant, so we simply + /// broadcast them into a vector. + Value *getVectorValue(Value *V); + + /// The original loop. + Loop *Orig; + // Scev analysis to use. + ScalarEvolution *SE; + // Loop Info. + LoopInfo *LI; + // The vectorization factor to use. + unsigned VF; + + // The builder that we use + IRBuilder<> *Builder; + + // --- Vectorization state --- + + /// The new Induction variable which was added to the new block. + Instruction *Induction; + /// The induction variable of the old basic block. + Instruction *OldInduction; + // Maps scalars to widened vectors. + DenseMap WidenMap; +}; + + +/// Perform the vectorization legality check. This class does not look at the +/// profitability of vectorization, only the legality. At the moment the checks +/// are very simple and focus on single basic block loops with a constant +/// iteration count and no reductions. +class LoopVectorizationLegality { +public: + LoopVectorizationLegality(Loop *Lp, ScalarEvolution *Se, DataLayout *Dl): + TheLoop(Lp), SE(Se), DL(Dl) { } + + /// Returns the maximum vectorization factor that we *can* use to vectorize + /// this loop. This does not mean that it is profitable to vectorize this + /// loop, only that it is legal to do so. This may be a large number. We + /// can vectorize to any SIMD width below this number. + unsigned getLoopMaxVF(); + +private: + /// Check if a single basic block loop is vectorizable. + /// At this point we know that this is a loop with a constant trip count + /// and we only need to check individual instructions. + bool canVectorizeBlock(BasicBlock &BB); + + // Check if a pointer value is known to be disjoint. + // Example: Alloca, Global, NoAlias. + bool isKnownDisjoint(Value* Val); + + /// The loop that we evaluate. + Loop *TheLoop; + /// Scev analysis. + ScalarEvolution *SE; + /// DataLayout analysis. + DataLayout *DL; +}; + +struct LoopVectorize : public LoopPass { + static char ID; // Pass identification, replacement for typeid + + LoopVectorize() : LoopPass(ID) { + initializeLoopVectorizePass(*PassRegistry::getPassRegistry()); + } + + AliasAnalysis *AA; + ScalarEvolution *SE; + DataLayout *DL; + LoopInfo *LI; + + virtual bool runOnLoop(Loop *L, LPPassManager &LPM) { + // Only vectorize innermost loops. + if (!L->empty()) + return false; + + AA = &getAnalysis(); + SE = &getAnalysis(); + DL = getAnalysisIfAvailable(); + LI = &getAnalysis(); + + BasicBlock *Header = L->getHeader(); + DEBUG(dbgs() << "LV: Checking a loop in \"" << + Header->getParent()->getName() << "\"\n"); + + // Check if it is legal to vectorize the loop. + LoopVectorizationLegality LVL(L, SE, DL); + unsigned MaxVF = LVL.getLoopMaxVF(); + + // Check that we can vectorize using the chosen vectorization width. + if ((MaxVF < DefaultVectorizationFactor) || + (MaxVF % DefaultVectorizationFactor)) { + DEBUG(dbgs() << "LV: non-vectorizable MaxVF ("<< MaxVF << ").\n"); + return false; + } + + DEBUG(dbgs() << "LV: Found a vectorizable loop ("<< MaxVF << ").\n"); + + // If we decided that is is *legal* to vectorizer the loop. Do it. + SingleBlockLoopVectorizer LB(L, SE, LI, DefaultVectorizationFactor); + LB.vectorize(); + + // The loop is now vectorized. Remove it from LMP. + LPM.deleteLoopFromQueue(L); + return true; + } + + virtual void getAnalysisUsage(AnalysisUsage &AU) const { + LoopPass::getAnalysisUsage(AU); + AU.addRequiredID(LoopSimplifyID); + AU.addRequired(); + AU.addRequired(); + AU.addRequired(); + } + +}; + +Value *SingleBlockLoopVectorizer::getBroadcastInstrs(Value *V) { + // Instructions that access the old induction variable + // actually want to get the new one. + if (V == OldInduction) + V = Induction; + // Create the types. + LLVMContext &C = V->getContext(); + Type *VTy = VectorType::get(V->getType(), VF); + Type *I32 = IntegerType::getInt32Ty(C); + Constant *Zero = ConstantInt::get(I32, 0); + Value *Zeros = ConstantAggregateZero::get(VectorType::get(I32, VF)); + Value *UndefVal = UndefValue::get(VTy); + // Insert the value into a new vector. + Value *SingleElem = Builder->CreateInsertElement(UndefVal, V, Zero); + // Broadcast the scalar into all locations in the vector. + Value *Shuf = Builder->CreateShuffleVector(SingleElem, UndefVal, Zeros, + "broadcast"); + // We are accessing the induction variable. Make sure to promote the + // index for each consecutive SIMD lane. This adds 0,1,2 ... to all lanes. + if (V == Induction) + return getConsecutiveVector(Shuf); + return Shuf; +} + +Value *SingleBlockLoopVectorizer::getConsecutiveVector(Value* Val) { + assert(Val->getType()->isVectorTy() && "Must be a vector"); + assert(Val->getType()->getScalarType()->isIntegerTy() && + "Elem must be an integer"); + // Create the types. + Type *ITy = Val->getType()->getScalarType(); + VectorType *Ty = cast(Val->getType()); + unsigned VLen = Ty->getNumElements(); + SmallVector Indices; + + // Create a vector of consecutive numbers from zero to VF. + for (unsigned i = 0; i < VLen; ++i) + Indices.push_back(ConstantInt::get(ITy, i)); + + // Add the consecutive indices to the vector value. + Constant *Cv = ConstantVector::get(Indices); + assert(Cv->getType() == Val->getType() && "Invalid consecutive vec"); + return Builder->CreateAdd(Val, Cv, "induction"); +} + + +bool SingleBlockLoopVectorizer::isConsecutiveGep(GetElementPtrInst *Gep) { + if (!Gep) + return false; + + unsigned NumOperands = Gep->getNumOperands(); + Value *LastIndex = Gep->getOperand(NumOperands - 1); + + // Check that all of the gep indices are uniform except for the last. + for (unsigned i = 0; i < NumOperands - 1; ++i) + if (!SE->isLoopInvariant(SE->getSCEV(Gep->getOperand(i)), Orig)) + return false; + + // The last operand has to be the induction in order to emit + // a wide load/store. + const SCEV *Last = SE->getSCEV(LastIndex); + if (const SCEVAddRecExpr *AR = dyn_cast(Last)) { + const SCEV *Step = AR->getStepRecurrence(*SE); + + // The memory is consecutive because the last index is consecutive + // and all other indices are loop invariant. + if (Step->isOne()) + return true; + } + + return false; +} + +Value *SingleBlockLoopVectorizer::getVectorValue(Value *V) { + if (WidenMap.count(V)) + return WidenMap[V]; + return getBroadcastInstrs(V); +} + +void SingleBlockLoopVectorizer::scalarizeInstruction(Instruction *Instr) { + assert(!Instr->getType()->isAggregateType() && "Can't handle vectors"); + // Holds vector parameters or scalars, in case of uniform vals. + SmallVector Params; + + // Find all of the vectorized parameters. + for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) { + Value *SrcOp = Instr->getOperand(op); + + // If we are accessing the old induction variable, use the new one. + if (SrcOp == OldInduction) { + Params.push_back(getBroadcastInstrs(Induction)); + continue; + } + + // Try using previously calculated values. + Instruction *SrcInst = dyn_cast(SrcOp); + + // If the src is an instruction that appeared earlier in the basic block + // then it should already be vectorized. + if (SrcInst && SrcInst->getParent() == Instr->getParent()) { + assert(WidenMap.count(SrcInst) && "Source operand is unavailable"); + // The parameter is a vector value from earlier. + Params.push_back(WidenMap[SrcInst]); + } else { + // The parameter is a scalar from outside the loop. Maybe even a constant. + Params.push_back(SrcOp); + } + } + + assert(Params.size() == Instr->getNumOperands() && + "Invalid number of operands"); + + // Does this instruction return a value ? + bool IsVoidRetTy = Instr->getType()->isVoidTy(); + Value *VecResults = 0; + + // If we have a return value, create an empty vector. We place the scalarized + // instructions in this vector. + if (!IsVoidRetTy) + VecResults = UndefValue::get(VectorType::get(Instr->getType(), VF)); + + // For each scalar that we create. + for (unsigned i = 0; i < VF; ++i) { + Instruction *Cloned = Instr->clone(); + if (!IsVoidRetTy) + Cloned->setName(Instr->getName() + ".cloned"); + // Replace the operands of the cloned instrucions with extracted scalars. + for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) { + Value *Op = Params[op]; + // Param is a vector. Need to extract the right lane. + if (Op->getType()->isVectorTy()) + Op = Builder->CreateExtractElement(Op, Builder->getInt32(i)); + Cloned->setOperand(op, Op); + } + + // Place the clonsed scalar in the new loop. + Builder->Insert(Cloned); + + // If the original scalar returns a value we need to place it in a vector + // so that future users will be able to use it. + if (!IsVoidRetTy) + VecResults = Builder->CreateInsertElement(VecResults, Cloned, + Builder->getInt32(i)); + } + + if (!IsVoidRetTy) + WidenMap[Instr] = VecResults; +} + +void SingleBlockLoopVectorizer::copyEmptyLoop() { + assert(Orig->getNumBlocks() == 1 && "Invalid loop"); + BasicBlock *PH = Orig->getLoopPreheader(); + BasicBlock *ExitBlock = Orig->getExitBlock(); + assert(ExitBlock && "Invalid loop exit"); + + // Create a new single-basic block loop. + BasicBlock *BB = BasicBlock::Create(PH->getContext(), "vectorizedloop", + PH->getParent(), ExitBlock); + + // Find the induction variable. + BasicBlock *OldBasicBlock = Orig->getHeader(); + PHINode *OldInd = dyn_cast(OldBasicBlock->begin()); + assert(OldInd && "We must have a single phi node."); + Type *IdxTy = OldInd->getType(); + + // Use this IR builder to create the loop instructions (Phi, Br, Cmp) + // inside the loop. + Builder = new IRBuilder<>(BB); + Builder->SetInsertPoint(BB); + + // Generate the induction variable. + PHINode *Phi = Builder->CreatePHI(IdxTy, 2, "index"); + Constant *Zero = ConstantInt::get(IdxTy, 0); + Constant *Step = ConstantInt::get(IdxTy, VF); + + // Find the loop boundaries. + const SCEV *ExitCount = SE->getExitCount(Orig, Orig->getHeader()); + assert(ExitCount != SE->getCouldNotCompute() && "Invalid loop count"); + + // Get the trip count from the count by adding 1. + ExitCount = SE->getAddExpr(ExitCount, + SE->getConstant(ExitCount->getType(), 1)); + + // Expand the trip count and place the new instructions in the preheader. + // Notice that the pre-header does not change, only the loop body. + SCEVExpander Exp(*SE, "induction"); + Instruction *Loc = Orig->getLoopPreheader()->getTerminator(); + if (ExitCount->getType() != Phi->getType()) + ExitCount = SE->getSignExtendExpr(ExitCount, Phi->getType()); + Value *Count = Exp.expandCodeFor(ExitCount, Phi->getType(), Loc); + + // Create i+1 and fill the PHINode. + Value *Next = Builder->CreateAdd(Phi, Step, "index.next"); + Phi->addIncoming(Zero, PH); + Phi->addIncoming(Next, BB); + // Create the compare. + Value *ICmp = Builder->CreateICmpEQ(Next, Count); + Builder->CreateCondBr(ICmp, ExitBlock, BB); + // Fix preheader. + PH->getTerminator()->setSuccessor(0, BB); + Builder->SetInsertPoint(BB->getFirstInsertionPt()); + + // Save the indiction variables. + Induction = Phi; + OldInduction = OldInd; +} + +void SingleBlockLoopVectorizer::vectorizeLoop() { + BasicBlock &BB = *Orig->getHeader(); + + // For each instruction in the old loop. + for (BasicBlock::iterator it = BB.begin(), e = BB.end(); it != e; ++it) { + Instruction *Inst = it; + + switch (Inst->getOpcode()) { + case Instruction::PHI: + case Instruction::Br: + // Nothing to do for PHIs and BR, since we already took care of the + // loop control flow instructions. + continue; + + case Instruction::Add: + case Instruction::FAdd: + case Instruction::Sub: + case Instruction::FSub: + case Instruction::Mul: + case Instruction::FMul: + case Instruction::UDiv: + case Instruction::SDiv: + case Instruction::FDiv: + case Instruction::URem: + case Instruction::SRem: + case Instruction::FRem: + case Instruction::Shl: + case Instruction::LShr: + case Instruction::AShr: + case Instruction::And: + case Instruction::Or: + case Instruction::Xor: { + // Just widen binops. + BinaryOperator *BinOp = dyn_cast(Inst); + Value *A = getVectorValue(Inst->getOperand(0)); + Value *B = getVectorValue(Inst->getOperand(1)); + // Use this vector value for all users of the original instruction. + WidenMap[Inst] = Builder->CreateBinOp(BinOp->getOpcode(), A, B); + break; + } + case Instruction::Select: { + // Widen selects. + Value *A = getVectorValue(Inst->getOperand(0)); + Value *B = getVectorValue(Inst->getOperand(1)); + Value *C = getVectorValue(Inst->getOperand(2)); + WidenMap[Inst] = Builder->CreateSelect(A, B, C); + break; + } + + case Instruction::ICmp: + case Instruction::FCmp: { + // Widen compares. Generate vector compares. + bool FCmp = (Inst->getOpcode() == Instruction::FCmp); + CmpInst *Cmp = dyn_cast(Inst); + Value *A = getVectorValue(Inst->getOperand(0)); + Value *B = getVectorValue(Inst->getOperand(1)); + if (FCmp) + WidenMap[Inst] = Builder->CreateFCmp(Cmp->getPredicate(), A, B); + else + WidenMap[Inst] = Builder->CreateICmp(Cmp->getPredicate(), A, B); + break; + } + + case Instruction::Store: { + // Attempt to issue a wide store. + StoreInst *SI = dyn_cast(Inst); + Type *StTy = VectorType::get(SI->getValueOperand()->getType(), VF); + Value *Ptr = SI->getPointerOperand(); + unsigned Alignment = SI->getAlignment(); + GetElementPtrInst *Gep = dyn_cast(Ptr); + // This store does not use GEPs. + if (!isConsecutiveGep(Gep)) { + scalarizeInstruction(Inst); + break; + } + + // Create the new GEP with the new induction variable. + GetElementPtrInst *Gep2 = cast(Gep->clone()); + unsigned NumOperands = Gep->getNumOperands(); + Gep2->setOperand(NumOperands - 1, Induction); + Ptr = Builder->Insert(Gep2); + Ptr = Builder->CreateBitCast(Ptr, StTy->getPointerTo()); + Value *Val = getVectorValue(SI->getValueOperand()); + Builder->CreateStore(Val, Ptr)->setAlignment(Alignment); + break; + } + case Instruction::Load: { + // Attempt to issue a wide load. + LoadInst *LI = dyn_cast(Inst); + Type *RetTy = VectorType::get(LI->getType(), VF); + Value *Ptr = LI->getPointerOperand(); + unsigned Alignment = LI->getAlignment(); + GetElementPtrInst *Gep = dyn_cast(Ptr); + + // We don't have a gep. Scalarize the load. + if (!isConsecutiveGep(Gep)) { + scalarizeInstruction(Inst); + break; + } + + // Create the new GEP with the new induction variable. + GetElementPtrInst *Gep2 = cast(Gep->clone()); + unsigned NumOperands = Gep->getNumOperands(); + Gep2->setOperand(NumOperands - 1, Induction); + Ptr = Builder->Insert(Gep2); + Ptr = Builder->CreateBitCast(Ptr, RetTy->getPointerTo()); + LI = Builder->CreateLoad(Ptr); + LI->setAlignment(Alignment); + // Use this vector value for all users of the load. + WidenMap[Inst] = LI; + break; + } + case Instruction::ZExt: + case Instruction::SExt: + case Instruction::FPToUI: + case Instruction::FPToSI: + case Instruction::FPExt: + case Instruction::PtrToInt: + case Instruction::IntToPtr: + case Instruction::SIToFP: + case Instruction::UIToFP: + case Instruction::Trunc: + case Instruction::FPTrunc: + case Instruction::BitCast: { + /// Vectorize bitcasts. + CastInst *CI = dyn_cast(Inst); + Value *A = getVectorValue(Inst->getOperand(0)); + Type *DestTy = VectorType::get(CI->getType()->getScalarType(), VF); + WidenMap[Inst] = Builder->CreateCast(CI->getOpcode(), A, DestTy); + break; + } + + default: + /// All other instructions are unsupported. Scalarize them. + scalarizeInstruction(Inst); + break; + }// end of switch. + }// end of for_each instr. +} + +void SingleBlockLoopVectorizer::deleteOldLoop() { + // The original basic block. + BasicBlock *BB = Orig->getHeader(); + SE->forgetLoop(Orig); + + LI->removeBlock(BB); + Orig->addBasicBlockToLoop(Induction->getParent(), LI->getBase()); + + // Remove the old loop block. + DeleteDeadBlock(BB); +} + +unsigned LoopVectorizationLegality::getLoopMaxVF() { + if (!TheLoop->getLoopPreheader()) { + assert(false && "No preheader!!"); + DEBUG(dbgs() << "LV: Loop not normalized." << "\n"); + return 1; + } + + // We can only vectorize single basic block loops. + unsigned NumBlocks = TheLoop->getNumBlocks(); + if (NumBlocks != 1) { + DEBUG(dbgs() << "LV: Too many blocks:" << NumBlocks << "\n"); + return 1; + } + + // We need to have a loop header. + BasicBlock *BB = TheLoop->getHeader(); + DEBUG(dbgs() << "LV: Found a loop: " << BB->getName() << "\n"); + + // Find the max vectorization factor. + unsigned MaxVF = SE->getSmallConstantTripMultiple(TheLoop, BB); + + + // Perform an early check. Do not scan the block if we did not find a loop. + if (MaxVF < 2) { + DEBUG(dbgs() << "LV: Can't find a vectorizable loop structure\n"); + return 1; + } + + // Go over each instruction and look at memory deps. + if (!canVectorizeBlock(*BB)) { + DEBUG(dbgs() << "LV: Can't vectorize this loop header\n"); + return 1; + } + + DEBUG(dbgs() << "LV: We can vectorize this loop! VF="< ValueVector; + ValueVector Reads; + ValueVector Writes; + + unsigned NumPhis = 0; + for (BasicBlock::iterator it = BB.begin(), e = BB.end(); it != e; ++it) { + Instruction *I = it; + + PHINode *Phi = dyn_cast(I); + if (Phi) { + NumPhis++; + // We only look at integer phi nodes. + if (!Phi->getType()->isIntegerTy()) { + DEBUG(dbgs() << "LV: Found an non-int PHI.\n"); + return false; + } + + // If we found an induction variable. + if (NumPhis > 1) { + DEBUG(dbgs() << "LV: Found more than one PHI.\n"); + return false; + } + + // This should not happen because the loop should be normalized. + if (Phi->getNumIncomingValues() != 2) { + DEBUG(dbgs() << "LV: Found an invalid PHI.\n"); + return false; + } + + // Check that the PHI is consecutive and starts at zero. + const SCEV *PhiScev = SE->getSCEV(Phi); + const SCEVAddRecExpr *AR = dyn_cast(PhiScev); + if (!AR) { + DEBUG(dbgs() << "LV: PHI is not a poly recurrence.\n"); + return false; + } + + const SCEV *Step = AR->getStepRecurrence(*SE); + const SCEV *Start = AR->getStart(); + + if (!Step->isOne() || !Start->isZero()) { + DEBUG(dbgs() << "LV: PHI does not start at zero or steps by one.\n"); + return false; + } + } + + // IF this is a load, record its pointer. If it is not a load, abort. + // Notice that we don't handle function calls that read or write. + if (I->mayReadFromMemory()) { + LoadInst *Ld = dyn_cast(I); + if (!Ld) return false; + if (!Ld->isSimple()) { + DEBUG(dbgs() << "LV: Found a non-simple load.\n"); + return false; + } + GetUnderlyingObjects(Ld->getPointerOperand(), Reads, DL); + } + + // Record store pointers. Abort on all other instructions that write to + // memory. + if (I->mayWriteToMemory()) { + StoreInst *St = dyn_cast(I); + if (!St) return false; + if (!St->isSimple()) { + DEBUG(dbgs() << "LV: Found a non-simple store.\n"); + return false; + } + GetUnderlyingObjects(St->getPointerOperand(), Writes, DL); + } + + // We still don't handle functions. + CallInst *CI = dyn_cast(I); + if (CI) { + DEBUG(dbgs() << "LV: Found a call site:"<< + CI->getCalledFunction()->getName() << "\n"); + return false; + } + + // We do not re-vectorize vectors. + if (!VectorType::isValidElementType(I->getType()) && + !I->getType()->isVoidTy()) { + DEBUG(dbgs() << "LV: Found unvectorizable type." << "\n"); + return false; + } + //Check that all of the users of the loop are inside the BB. + for (Value::use_iterator it = I->use_begin(), e = I->use_end(); + it != e; ++it) { + Instruction *U = cast(*it); + BasicBlock *Parent = U->getParent(); + if (Parent != &BB) { + DEBUG(dbgs() << "LV: Found an outside user for : "<< *U << "\n"); + return false; + } + } + } // next instr. + + // Check that the underlying objects of the reads and writes are either + // disjoint memory locations, or that they are no-alias arguments. + ValueVector::iterator r, re, w, we; + for (r = Reads.begin(), re = Reads.end(); r != re; ++r) { + if (!isKnownDisjoint(*r)) { + DEBUG(dbgs() << "LV: Found a bad read Ptr: "<< **r << "\n"); + return false; + } + } + + for (w = Writes.begin(), we = Writes.end(); w != we; ++w) { + if (!isKnownDisjoint(*w)) { + DEBUG(dbgs() << "LV: Found a bad write Ptr: "<< **w << "\n"); + return false; + } + } + + // Check that there are no multiple write locations to the same pointer. + SmallPtrSet BasePointers; + for (w = Writes.begin(), we = Writes.end(); w != we; ++w) { + if (BasePointers.count(*w)) { + DEBUG(dbgs() << "LV: Multiple writes to the same index :"<< **w << "\n"); + return false; + } + BasePointers.insert(*w); + } + + // Sort the writes vector so that we can use a binary search. + std::sort(Writes.begin(), Writes.end()); + // Check that the reads and the writes are disjoint. + for (r = Reads.begin(), re = Reads.end(); r != re; ++r) { + if (std::binary_search(Writes.begin(), Writes.end(), *r)) { + DEBUG(dbgs() << "Vectorizer: Found a read/write ptr:"<< **r << "\n"); + return false; + } + } + + // All is okay. + return true; +} + +/// Checks if the value is a Global variable or if it is an Arguments +/// marked with the NoAlias attribute. +bool LoopVectorizationLegality::isKnownDisjoint(Value* Val) { + assert(Val && "Invalid value"); + if (dyn_cast(Val)) + return true; + if (dyn_cast(Val)) + return true; + Argument *A = dyn_cast(Val); + if (!A) + return false; + return A->hasNoAliasAttr(); +} + +} // namespace + +char LoopVectorize::ID = 0; +static const char lv_name[] = "Loop Vectorization"; +INITIALIZE_PASS_BEGIN(LoopVectorize, LV_NAME, lv_name, false, false) +INITIALIZE_AG_DEPENDENCY(AliasAnalysis) +INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) +INITIALIZE_PASS_DEPENDENCY(LoopSimplify) +INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false) + +namespace llvm { + Pass *createLoopVectorizePass() { + return new LoopVectorize(); + } + +} + diff --git a/lib/Transforms/Vectorize/Vectorize.cpp b/lib/Transforms/Vectorize/Vectorize.cpp index 1ef60029bcf..d26973a7b38 100644 --- a/lib/Transforms/Vectorize/Vectorize.cpp +++ b/lib/Transforms/Vectorize/Vectorize.cpp @@ -7,7 +7,7 @@ // //===----------------------------------------------------------------------===// // -// This file implements common infrastructure for libLLVMVectorizeOpts.a, which +// This file implements common infrastructure for libLLVMVectorizeOpts.a, which // implements several vectorization transformations over the LLVM intermediate // representation, including the C bindings for that library. // @@ -23,10 +23,11 @@ using namespace llvm; -/// initializeVectorizationPasses - Initialize all passes linked into the +/// initializeVectorizationPasses - Initialize all passes linked into the /// Vectorization library. void llvm::initializeVectorization(PassRegistry &Registry) { initializeBBVectorizePass(Registry); + initializeLoopVectorizePass(Registry); } void LLVMInitializeVectorization(LLVMPassRegistryRef R) { @@ -37,3 +38,6 @@ void LLVMAddBBVectorizePass(LLVMPassManagerRef PM) { unwrap(PM)->add(createBBVectorizePass()); } +void LLVMAddLoopVectorizePass(LLVMPassManagerRef PM) { + unwrap(PM)->add(createLoopVectorizePass()); +} diff --git a/test/Transforms/LoopVectorize/gcc-examples.ll b/test/Transforms/LoopVectorize/gcc-examples.ll new file mode 100644 index 00000000000..68eab9bae76 --- /dev/null +++ b/test/Transforms/LoopVectorize/gcc-examples.ll @@ -0,0 +1,651 @@ +; RUN: opt < %s -loop-vectorize -dce -instcombine -licm -S | FileCheck %s + +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.8.0" + +@b = common global [2048 x i32] zeroinitializer, align 16 +@c = common global [2048 x i32] zeroinitializer, align 16 +@a = common global [2048 x i32] zeroinitializer, align 16 +@G = common global [32 x [1024 x i32]] zeroinitializer, align 16 +@ub = common global [1024 x i32] zeroinitializer, align 16 +@uc = common global [1024 x i32] zeroinitializer, align 16 +@d = common global [2048 x i32] zeroinitializer, align 16 +@fa = common global [1024 x float] zeroinitializer, align 16 +@fb = common global [1024 x float] zeroinitializer, align 16 +@ic = common global [1024 x i32] zeroinitializer, align 16 +@da = common global [1024 x float] zeroinitializer, align 16 +@db = common global [1024 x float] zeroinitializer, align 16 +@dc = common global [1024 x float] zeroinitializer, align 16 +@dd = common global [1024 x float] zeroinitializer, align 16 +@dj = common global [1024 x i32] zeroinitializer, align 16 + +;CHECK: @example1 +;CHECK: load <4 x i32> +;CHECK: add <4 x i32> +;CHECK: store <4 x i32> +;CHECK: ret void +define void @example1() nounwind uwtable ssp { + br label %1 + +;