Add a basic-block autovectorization pass.
This is the initial checkin of the basic-block autovectorization pass along with some supporting vectorization infrastructure.
Special thanks to everyone who helped review this code over the last several months (especially Tobias Grosser).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149468 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/CMakeLists.txt b/lib/Transforms/CMakeLists.txt
index 10e0cc6..de1353e 100644
--- a/lib/Transforms/CMakeLists.txt
+++ b/lib/Transforms/CMakeLists.txt
@@ -3,4 +3,5 @@
add_subdirectory(InstCombine)
add_subdirectory(Scalar)
add_subdirectory(IPO)
+add_subdirectory(Vectorize)
add_subdirectory(Hello)
diff --git a/lib/Transforms/IPO/LLVMBuild.txt b/lib/Transforms/IPO/LLVMBuild.txt
index b358fab..b18c915 100644
--- a/lib/Transforms/IPO/LLVMBuild.txt
+++ b/lib/Transforms/IPO/LLVMBuild.txt
@@ -20,4 +20,4 @@
name = IPO
parent = Transforms
library_name = ipo
-required_libraries = Analysis Core IPA InstCombine Scalar Support Target TransformUtils
+required_libraries = Analysis Core IPA InstCombine Scalar Vectorize Support Target TransformUtils
diff --git a/lib/Transforms/IPO/PassManagerBuilder.cpp b/lib/Transforms/IPO/PassManagerBuilder.cpp
index afd25dc..8408437 100644
--- a/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -21,14 +21,20 @@
#include "llvm/DefaultPasses.h"
#include "llvm/PassManager.h"
#include "llvm/Analysis/Passes.h"
+#include "llvm/Analysis/Verifier.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Vectorize.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/ManagedStatic.h"
using namespace llvm;
+static cl::opt<bool>
+RunVectorization("vectorize", cl::desc("Run vectorization passes"));
+
PassManagerBuilder::PassManagerBuilder() {
OptLevel = 2;
SizeLevel = 0;
@@ -37,6 +43,7 @@
DisableSimplifyLibCalls = false;
DisableUnitAtATime = false;
DisableUnrollLoops = false;
+ Vectorize = RunVectorization;
}
PassManagerBuilder::~PassManagerBuilder() {
@@ -172,6 +179,13 @@
addExtensionsToPM(EP_ScalarOptimizerLate, MPM);
+ if (Vectorize) {
+ MPM.add(createBBVectorizePass());
+ MPM.add(createInstructionCombiningPass());
+ if (OptLevel > 1)
+ MPM.add(createGVNPass()); // Remove redundancies
+ }
+
MPM.add(createAggressiveDCEPass()); // Delete dead instructions
MPM.add(createCFGSimplificationPass()); // Merge & remove BBs
MPM.add(createInstructionCombiningPass()); // Clean up after everything.
diff --git a/lib/Transforms/LLVMBuild.txt b/lib/Transforms/LLVMBuild.txt
index b2ef49a..f7bca06 100644
--- a/lib/Transforms/LLVMBuild.txt
+++ b/lib/Transforms/LLVMBuild.txt
@@ -16,7 +16,7 @@
;===------------------------------------------------------------------------===;
[common]
-subdirectories = IPO InstCombine Instrumentation Scalar Utils
+subdirectories = IPO InstCombine Instrumentation Scalar Utils Vectorize
[component_0]
type = Group
diff --git a/lib/Transforms/Makefile b/lib/Transforms/Makefile
index e527be2..8b1df92 100644
--- a/lib/Transforms/Makefile
+++ b/lib/Transforms/Makefile
@@ -8,7 +8,7 @@
##===----------------------------------------------------------------------===##
LEVEL = ../..
-PARALLEL_DIRS = Utils Instrumentation Scalar InstCombine IPO Hello
+PARALLEL_DIRS = Utils Instrumentation Scalar InstCombine IPO Vectorize Hello
include $(LEVEL)/Makefile.config
diff --git a/lib/Transforms/Vectorize/BBVectorize.cpp b/lib/Transforms/Vectorize/BBVectorize.cpp
new file mode 100644
index 0000000..9c2c8dd
--- /dev/null
+++ b/lib/Transforms/Vectorize/BBVectorize.cpp
@@ -0,0 +1,1796 @@
+//===- BBVectorize.cpp - A Basic-Block Vectorizer -------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a basic-block vectorization pass. The algorithm was
+// inspired by that used by the Vienna MAP Vectorizor by Franchetti and Kral,
+// et al. It works by looking for chains of pairable operations and then
+// pairing them.
+//
+//===----------------------------------------------------------------------===//
+
+#define BBV_NAME "bb-vectorize"
+#define DEBUG_TYPE BBV_NAME
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Pass.h"
+#include "llvm/Type.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AliasSetTracker.h"
+#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/ValueHandle.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Vectorize.h"
+#include <algorithm>
+#include <map>
+using namespace llvm;
+
+static cl::opt<unsigned>
+ReqChainDepth("bb-vectorize-req-chain-depth", cl::init(6), cl::Hidden,
+ cl::desc("The required chain depth for vectorization"));
+
+static cl::opt<unsigned>
+SearchLimit("bb-vectorize-search-limit", cl::init(400), cl::Hidden,
+ cl::desc("The maximum search distance for instruction pairs"));
+
+static cl::opt<bool>
+SplatBreaksChain("bb-vectorize-splat-breaks-chain", cl::init(false), cl::Hidden,
+ cl::desc("Replicating one element to a pair breaks the chain"));
+
+static cl::opt<unsigned>
+VectorBits("bb-vectorize-vector-bits", cl::init(128), cl::Hidden,
+ cl::desc("The size of the native vector registers"));
+
+static cl::opt<unsigned>
+MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden,
+ cl::desc("The maximum number of pairing iterations"));
+
+static cl::opt<unsigned>
+MaxCandPairsForCycleCheck("bb-vectorize-max-cycle-check-pairs", cl::init(200),
+ cl::Hidden, cl::desc("The maximum number of candidate pairs with which to use"
+ " a full cycle check"));
+
+static cl::opt<bool>
+NoInts("bb-vectorize-no-ints", cl::init(false), cl::Hidden,
+ cl::desc("Don't try to vectorize integer values"));
+
+static cl::opt<bool>
+NoFloats("bb-vectorize-no-floats", cl::init(false), cl::Hidden,
+ cl::desc("Don't try to vectorize floating-point values"));
+
+static cl::opt<bool>
+NoCasts("bb-vectorize-no-casts", cl::init(false), cl::Hidden,
+ cl::desc("Don't try to vectorize casting (conversion) operations"));
+
+static cl::opt<bool>
+NoMath("bb-vectorize-no-math", cl::init(false), cl::Hidden,
+ cl::desc("Don't try to vectorize floating-point math intrinsics"));
+
+static cl::opt<bool>
+NoFMA("bb-vectorize-no-fma", cl::init(false), cl::Hidden,
+ cl::desc("Don't try to vectorize the fused-multiply-add intrinsic"));
+
+static cl::opt<bool>
+NoMemOps("bb-vectorize-no-mem-ops", cl::init(false), cl::Hidden,
+ cl::desc("Don't try to vectorize loads and stores"));
+
+static cl::opt<bool>
+AlignedOnly("bb-vectorize-aligned-only", cl::init(false), cl::Hidden,
+ cl::desc("Only generate aligned loads and stores"));
+
+static cl::opt<bool>
+FastDep("bb-vectorize-fast-dep", cl::init(false), cl::Hidden,
+ cl::desc("Use a fast instruction dependency analysis"));
+
+#ifndef NDEBUG
+static cl::opt<bool>
+DebugInstructionExamination("bb-vectorize-debug-instruction-examination",
+ cl::init(false), cl::Hidden,
+ cl::desc("When debugging is enabled, output information on the"
+ " instruction-examination process"));
+static cl::opt<bool>
+DebugCandidateSelection("bb-vectorize-debug-candidate-selection",
+ cl::init(false), cl::Hidden,
+ cl::desc("When debugging is enabled, output information on the"
+ " candidate-selection process"));
+static cl::opt<bool>
+DebugPairSelection("bb-vectorize-debug-pair-selection",
+ cl::init(false), cl::Hidden,
+ cl::desc("When debugging is enabled, output information on the"
+ " pair-selection process"));
+static cl::opt<bool>
+DebugCycleCheck("bb-vectorize-debug-cycle-check",
+ cl::init(false), cl::Hidden,
+ cl::desc("When debugging is enabled, output information on the"
+ " cycle-checking process"));
+#endif
+
+STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize");
+
+namespace {
+ struct BBVectorize : public BasicBlockPass {
+ static char ID; // Pass identification, replacement for typeid
+ BBVectorize() : BasicBlockPass(ID) {
+ initializeBBVectorizePass(*PassRegistry::getPassRegistry());
+ }
+
+ typedef std::pair<Value *, Value *> ValuePair;
+ typedef std::pair<ValuePair, size_t> ValuePairWithDepth;
+ typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair
+ typedef std::pair<std::multimap<Value *, Value *>::iterator,
+ std::multimap<Value *, Value *>::iterator> VPIteratorPair;
+ typedef std::pair<std::multimap<ValuePair, ValuePair>::iterator,
+ std::multimap<ValuePair, ValuePair>::iterator>
+ VPPIteratorPair;
+
+ AliasAnalysis *AA;
+ ScalarEvolution *SE;
+ TargetData *TD;
+
+ // FIXME: const correct?
+
+ bool vectorizePairs(BasicBlock &BB);
+
+ void getCandidatePairs(BasicBlock &BB,
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts);
+
+ void computeConnectedPairs(std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs);
+
+ void buildDepMap(BasicBlock &BB,
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ DenseSet<ValuePair> &PairableInstUsers);
+
+ void choosePairs(std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ DenseSet<ValuePair> &PairableInstUsers,
+ DenseMap<Value *, Value *>& ChosenPairs);
+
+ void fuseChosenPairs(BasicBlock &BB,
+ std::vector<Value *> &PairableInsts,
+ DenseMap<Value *, Value *>& ChosenPairs);
+
+ bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore);
+
+ bool areInstsCompatible(Instruction *I, Instruction *J,
+ bool IsSimpleLoadStore);
+
+ bool trackUsesOfI(DenseSet<Value *> &Users,
+ AliasSetTracker &WriteSet, Instruction *I,
+ Instruction *J, bool UpdateUsers = true,
+ std::multimap<Value *, Value *> *LoadMoveSet = 0);
+
+ void computePairsConnectedTo(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ ValuePair P);
+
+ bool pairsConflict(ValuePair P, ValuePair Q,
+ DenseSet<ValuePair> &PairableInstUsers,
+ std::multimap<ValuePair, ValuePair> *PairableInstUserMap = 0);
+
+ bool pairWillFormCycle(ValuePair P,
+ std::multimap<ValuePair, ValuePair> &PairableInstUsers,
+ DenseSet<ValuePair> &CurrentPairs);
+
+ void pruneTreeFor(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ DenseSet<ValuePair> &PairableInstUsers,
+ std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ DenseMap<ValuePair, size_t> &Tree,
+ DenseSet<ValuePair> &PrunedTree, ValuePair J,
+ bool UseCycleCheck);
+
+ void buildInitialTreeFor(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ DenseSet<ValuePair> &PairableInstUsers,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ DenseMap<ValuePair, size_t> &Tree, ValuePair J);
+
+ void findBestTreeFor(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ DenseSet<ValuePair> &PairableInstUsers,
+ std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
+ size_t &BestEffSize, VPIteratorPair ChoiceRange,
+ bool UseCycleCheck);
+
+ Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I,
+ Instruction *J, unsigned o, bool &FlipMemInputs);
+
+ void fillNewShuffleMask(LLVMContext& Context, Instruction *J,
+ unsigned NumElem, unsigned MaskOffset, unsigned NumInElem,
+ unsigned IdxOffset, std::vector<Constant*> &Mask);
+
+ Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I,
+ Instruction *J);
+
+ Value *getReplacementInput(LLVMContext& Context, Instruction *I,
+ Instruction *J, unsigned o, bool FlipMemInputs);
+
+ void getReplacementInputsForPair(LLVMContext& Context, Instruction *I,
+ Instruction *J, SmallVector<Value *, 3> &ReplacedOperands,
+ bool &FlipMemInputs);
+
+ void replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
+ Instruction *J, Instruction *K,
+ Instruction *&InsertionPt, Instruction *&K1,
+ Instruction *&K2, bool &FlipMemInputs);
+
+ void collectPairLoadMoveSet(BasicBlock &BB,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ std::multimap<Value *, Value *> &LoadMoveSet,
+ Instruction *I);
+
+ void collectLoadMoveSet(BasicBlock &BB,
+ std::vector<Value *> &PairableInsts,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ std::multimap<Value *, Value *> &LoadMoveSet);
+
+ bool canMoveUsesOfIAfterJ(BasicBlock &BB,
+ std::multimap<Value *, Value *> &LoadMoveSet,
+ Instruction *I, Instruction *J);
+
+ void moveUsesOfIAfterJ(BasicBlock &BB,
+ std::multimap<Value *, Value *> &LoadMoveSet,
+ Instruction *&InsertionPt,
+ Instruction *I, Instruction *J);
+
+ virtual bool runOnBasicBlock(BasicBlock &BB) {
+ AA = &getAnalysis<AliasAnalysis>();
+ SE = &getAnalysis<ScalarEvolution>();
+ TD = getAnalysisIfAvailable<TargetData>();
+
+ bool changed = false;
+ // Iterate a sufficient number of times to merge types of size 1 bit,
+ // then 2 bits, then 4, etc. up to half of the target vector width of the
+ // target vector register.
+ for (unsigned v = 2, n = 1; v <= VectorBits && (!MaxIter || n <= MaxIter);
+ v *= 2, ++n) {
+ DEBUG(dbgs() << "BBV: fusing loop #" << n <<
+ " for " << BB.getName() << " in " <<
+ BB.getParent()->getName() << "...\n");
+ if (vectorizePairs(BB))
+ changed = true;
+ else
+ break;
+ }
+
+ DEBUG(dbgs() << "BBV: done!\n");
+ return changed;
+ }
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ BasicBlockPass::getAnalysisUsage(AU);
+ AU.addRequired<AliasAnalysis>();
+ AU.addRequired<ScalarEvolution>();
+ AU.addPreserved<AliasAnalysis>();
+ AU.addPreserved<ScalarEvolution>();
+ }
+
+ // This returns the vector type that holds a pair of the provided type.
+ // If the provided type is already a vector, then its length is doubled.
+ static inline VectorType *getVecTypeForPair(Type *ElemTy) {
+ if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) {
+ unsigned numElem = VTy->getNumElements();
+ return VectorType::get(ElemTy->getScalarType(), numElem*2);
+ } else {
+ return VectorType::get(ElemTy, 2);
+ }
+ }
+
+ // Returns the weight associated with the provided value. A chain of
+ // candidate pairs has a length given by the sum of the weights of its
+ // members (one weight per pair; the weight of each member of the pair
+ // is assumed to be the same). This length is then compared to the
+ // chain-length threshold to determine if a given chain is significant
+ // enough to be vectorized. The length is also used in comparing
+ // candidate chains where longer chains are considered to be better.
+ // Note: when this function returns 0, the resulting instructions are
+ // not actually fused.
+ static inline size_t getDepthFactor(Value *V) {
+ // InsertElement and ExtractElement have a depth factor of zero. This is
+ // for two reasons: First, they cannot be usefully fused. Second, because
+ // the pass generates a lot of these, they can confuse the simple metric
+ // used to compare the trees in the next iteration. Thus, giving them a
+ // weight of zero allows the pass to essentially ignore them in
+ // subsequent iterations when looking for vectorization opportunities
+ // while still tracking dependency chains that flow through those
+ // instructions.
+ if (isa<InsertElementInst>(V) || isa<ExtractElementInst>(V))
+ return 0;
+
+ return 1;
+ }
+
+ // This determines the relative offset of two loads or stores, returning
+ // true if the offset could be determined to be some constant value.
+ // For example, if OffsetInElmts == 1, then J accesses the memory directly
+ // after I; if OffsetInElmts == -1 then I accesses the memory
+ // directly after J. This function assumes that both instructions
+ // have the same type.
+ bool getPairPtrInfo(Instruction *I, Instruction *J,
+ Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment,
+ int64_t &OffsetInElmts) {
+ OffsetInElmts = 0;
+ if (isa<LoadInst>(I)) {
+ IPtr = cast<LoadInst>(I)->getPointerOperand();
+ JPtr = cast<LoadInst>(J)->getPointerOperand();
+ IAlignment = cast<LoadInst>(I)->getAlignment();
+ JAlignment = cast<LoadInst>(J)->getAlignment();
+ } else {
+ IPtr = cast<StoreInst>(I)->getPointerOperand();
+ JPtr = cast<StoreInst>(J)->getPointerOperand();
+ IAlignment = cast<StoreInst>(I)->getAlignment();
+ JAlignment = cast<StoreInst>(J)->getAlignment();
+ }
+
+ const SCEV *IPtrSCEV = SE->getSCEV(IPtr);
+ const SCEV *JPtrSCEV = SE->getSCEV(JPtr);
+
+ // If this is a trivial offset, then we'll get something like
+ // 1*sizeof(type). With target data, which we need anyway, this will get
+ // constant folded into a number.
+ const SCEV *OffsetSCEV = SE->getMinusSCEV(JPtrSCEV, IPtrSCEV);
+ if (const SCEVConstant *ConstOffSCEV =
+ dyn_cast<SCEVConstant>(OffsetSCEV)) {
+ ConstantInt *IntOff = ConstOffSCEV->getValue();
+ int64_t Offset = IntOff->getSExtValue();
+
+ Type *VTy = cast<PointerType>(IPtr->getType())->getElementType();
+ int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy);
+
+ assert(VTy == cast<PointerType>(JPtr->getType())->getElementType());
+
+ OffsetInElmts = Offset/VTyTSS;
+ return (abs64(Offset) % VTyTSS) == 0;
+ }
+
+ return false;
+ }
+
+ // Returns true if the provided CallInst represents an intrinsic that can
+ // be vectorized.
+ bool isVectorizableIntrinsic(CallInst* I) {
+ Function *F = I->getCalledFunction();
+ if (!F) return false;
+
+ unsigned IID = F->getIntrinsicID();
+ if (!IID) return false;
+
+ switch(IID) {
+ default:
+ return false;
+ case Intrinsic::sqrt:
+ case Intrinsic::powi:
+ case Intrinsic::sin:
+ case Intrinsic::cos:
+ case Intrinsic::log:
+ case Intrinsic::log2:
+ case Intrinsic::log10:
+ case Intrinsic::exp:
+ case Intrinsic::exp2:
+ case Intrinsic::pow:
+ return !NoMath;
+ case Intrinsic::fma:
+ return !NoFMA;
+ }
+ }
+
+ // Returns true if J is the second element in some pair referenced by
+ // some multimap pair iterator pair.
+ template <typename V>
+ bool isSecondInIteratorPair(V J, std::pair<
+ typename std::multimap<V, V>::iterator,
+ typename std::multimap<V, V>::iterator> PairRange) {
+ for (typename std::multimap<V, V>::iterator K = PairRange.first;
+ K != PairRange.second; ++K)
+ if (K->second == J) return true;
+
+ return false;
+ }
+ };
+
+ // This function implements one vectorization iteration on the provided
+ // basic block. It returns true if the block is changed.
+ bool BBVectorize::vectorizePairs(BasicBlock &BB) {
+ std::vector<Value *> PairableInsts;
+ std::multimap<Value *, Value *> CandidatePairs;
+ getCandidatePairs(BB, CandidatePairs, PairableInsts);
+ if (PairableInsts.size() == 0) return false;
+
+ // Now we have a map of all of the pairable instructions and we need to
+ // select the best possible pairing. A good pairing is one such that the
+ // users of the pair are also paired. This defines a (directed) forest
+ // over the pairs such that two pairs are connected iff the second pair
+ // uses the first.
+
+ // Note that it only matters that both members of the second pair use some
+ // element of the first pair (to allow for splatting).
+
+ std::multimap<ValuePair, ValuePair> ConnectedPairs;
+ computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs);
+ if (ConnectedPairs.size() == 0) return false;
+
+ // Build the pairable-instruction dependency map
+ DenseSet<ValuePair> PairableInstUsers;
+ buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers);
+
+ // There is now a graph of the connected pairs. For each variable, pick the
+ // pairing with the largest tree meeting the depth requirement on at least
+ // one branch. Then select all pairings that are part of that tree and
+ // remove them from the list of available pairings and pairable variables.
+
+ DenseMap<Value *, Value *> ChosenPairs;
+ choosePairs(CandidatePairs, PairableInsts, ConnectedPairs,
+ PairableInstUsers, ChosenPairs);
+
+ if (ChosenPairs.size() == 0) return false;
+ NumFusedOps += ChosenPairs.size();
+
+ // A set of pairs has now been selected. It is now necessary to replace the
+ // paired instructions with vector instructions. For this procedure each
+ // operand much be replaced with a vector operand. This vector is formed
+ // by using build_vector on the old operands. The replaced values are then
+ // replaced with a vector_extract on the result. Subsequent optimization
+ // passes should coalesce the build/extract combinations.
+
+ fuseChosenPairs(BB, PairableInsts, ChosenPairs);
+
+ return true;
+ }
+
+ // This function returns true if the provided instruction is capable of being
+ // fused into a vector instruction. This determination is based only on the
+ // type and other attributes of the instruction.
+ bool BBVectorize::isInstVectorizable(Instruction *I,
+ bool &IsSimpleLoadStore) {
+ IsSimpleLoadStore = false;
+
+ if (CallInst *C = dyn_cast<CallInst>(I)) {
+ if (!isVectorizableIntrinsic(C))
+ return false;
+ } else if (LoadInst *L = dyn_cast<LoadInst>(I)) {
+ // Vectorize simple loads if possbile:
+ IsSimpleLoadStore = L->isSimple();
+ if (!IsSimpleLoadStore || NoMemOps)
+ return false;
+ } else if (StoreInst *S = dyn_cast<StoreInst>(I)) {
+ // Vectorize simple stores if possbile:
+ IsSimpleLoadStore = S->isSimple();
+ if (!IsSimpleLoadStore || NoMemOps)
+ return false;
+ } else if (CastInst *C = dyn_cast<CastInst>(I)) {
+ // We can vectorize casts, but not casts of pointer types, etc.
+ if (NoCasts)
+ return false;
+
+ Type *SrcTy = C->getSrcTy();
+ if (!SrcTy->isSingleValueType() || SrcTy->isPointerTy())
+ return false;
+
+ Type *DestTy = C->getDestTy();
+ if (!DestTy->isSingleValueType() || DestTy->isPointerTy())
+ return false;
+ } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) ||
+ isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) {
+ return false;
+ }
+
+ // We can't vectorize memory operations without target data
+ if (TD == 0 && IsSimpleLoadStore)
+ return false;
+
+ Type *T1, *T2;
+ if (isa<StoreInst>(I)) {
+ // For stores, it is the value type, not the pointer type that matters
+ // because the value is what will come from a vector register.
+
+ Value *IVal = cast<StoreInst>(I)->getValueOperand();
+ T1 = IVal->getType();
+ } else {
+ T1 = I->getType();
+ }
+
+ if (I->isCast())
+ T2 = cast<CastInst>(I)->getSrcTy();
+ else
+ T2 = T1;
+
+ // Not every type can be vectorized...
+ if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) ||
+ !(VectorType::isValidElementType(T2) || T2->isVectorTy()))
+ return false;
+
+ if (NoInts && (T1->isIntOrIntVectorTy() || T2->isIntOrIntVectorTy()))
+ return false;
+
+ if (NoFloats && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy()))
+ return false;
+
+ if (T1->getPrimitiveSizeInBits() > VectorBits/2 ||
+ T2->getPrimitiveSizeInBits() > VectorBits/2)
+ return false;
+
+ return true;
+ }
+
+ // This function returns true if the two provided instructions are compatible
+ // (meaning that they can be fused into a vector instruction). This assumes
+ // that I has already been determined to be vectorizable and that J is not
+ // in the use tree of I.
+ bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J,
+ bool IsSimpleLoadStore) {
+ DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I <<
+ " <-> " << *J << "\n");
+
+ // Loads and stores can be merged if they have different alignments,
+ // but are otherwise the same.
+ LoadInst *LI, *LJ;
+ StoreInst *SI, *SJ;
+ if ((LI = dyn_cast<LoadInst>(I)) && (LJ = dyn_cast<LoadInst>(J))) {
+ if (I->getType() != J->getType())
+ return false;
+
+ if (LI->getPointerOperand()->getType() !=
+ LJ->getPointerOperand()->getType() ||
+ LI->isVolatile() != LJ->isVolatile() ||
+ LI->getOrdering() != LJ->getOrdering() ||
+ LI->getSynchScope() != LJ->getSynchScope())
+ return false;
+ } else if ((SI = dyn_cast<StoreInst>(I)) && (SJ = dyn_cast<StoreInst>(J))) {
+ if (SI->getValueOperand()->getType() !=
+ SJ->getValueOperand()->getType() ||
+ SI->getPointerOperand()->getType() !=
+ SJ->getPointerOperand()->getType() ||
+ SI->isVolatile() != SJ->isVolatile() ||
+ SI->getOrdering() != SJ->getOrdering() ||
+ SI->getSynchScope() != SJ->getSynchScope())
+ return false;
+ } else if (!J->isSameOperationAs(I)) {
+ return false;
+ }
+ // FIXME: handle addsub-type operations!
+
+ if (IsSimpleLoadStore) {
+ Value *IPtr, *JPtr;
+ unsigned IAlignment, JAlignment;
+ int64_t OffsetInElmts = 0;
+ if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
+ OffsetInElmts) && abs64(OffsetInElmts) == 1) {
+ if (AlignedOnly) {
+ Type *aType = isa<StoreInst>(I) ?
+ cast<StoreInst>(I)->getValueOperand()->getType() : I->getType();
+ // An aligned load or store is possible only if the instruction
+ // with the lower offset has an alignment suitable for the
+ // vector type.
+
+ unsigned BottomAlignment = IAlignment;
+ if (OffsetInElmts < 0) BottomAlignment = JAlignment;
+
+ Type *VType = getVecTypeForPair(aType);
+ unsigned VecAlignment = TD->getPrefTypeAlignment(VType);
+ if (BottomAlignment < VecAlignment)
+ return false;
+ }
+ } else {
+ return false;
+ }
+ } else if (isa<ShuffleVectorInst>(I)) {
+ // Only merge two shuffles if they're both constant
+ return isa<Constant>(I->getOperand(2)) &&
+ isa<Constant>(J->getOperand(2));
+ // FIXME: We may want to vectorize non-constant shuffles also.
+ }
+
+ return true;
+ }
+
+ // Figure out whether or not J uses I and update the users and write-set
+ // structures associated with I. Specifically, Users represents the set of
+ // instructions that depend on I. WriteSet represents the set
+ // of memory locations that are dependent on I. If UpdateUsers is true,
+ // and J uses I, then Users is updated to contain J and WriteSet is updated
+ // to contain any memory locations to which J writes. The function returns
+ // true if J uses I. By default, alias analysis is used to determine
+ // whether J reads from memory that overlaps with a location in WriteSet.
+ // If LoadMoveSet is not null, then it is a previously-computed multimap
+ // where the key is the memory-based user instruction and the value is
+ // the instruction to be compared with I. So, if LoadMoveSet is provided,
+ // then the alias analysis is not used. This is necessary because this
+ // function is called during the process of moving instructions during
+ // vectorization and the results of the alias analysis are not stable during
+ // that process.
+ bool BBVectorize::trackUsesOfI(DenseSet<Value *> &Users,
+ AliasSetTracker &WriteSet, Instruction *I,
+ Instruction *J, bool UpdateUsers,
+ std::multimap<Value *, Value *> *LoadMoveSet) {
+ bool UsesI = false;
+
+ // This instruction may already be marked as a user due, for example, to
+ // being a member of a selected pair.
+ if (Users.count(J))
+ UsesI = true;
+
+ if (!UsesI)
+ for (User::op_iterator JU = J->op_begin(), e = J->op_end();
+ JU != e; ++JU) {
+ Value *V = *JU;
+ if (I == V || Users.count(V)) {
+ UsesI = true;
+ break;
+ }
+ }
+ if (!UsesI && J->mayReadFromMemory()) {
+ if (LoadMoveSet) {
+ VPIteratorPair JPairRange = LoadMoveSet->equal_range(J);
+ UsesI = isSecondInIteratorPair<Value*>(I, JPairRange);
+ } else {
+ for (AliasSetTracker::iterator W = WriteSet.begin(),
+ WE = WriteSet.end(); W != WE; ++W) {
+ for (AliasSet::iterator A = W->begin(), AE = W->end();
+ A != AE; ++A) {
+ AliasAnalysis::Location ptrLoc(A->getValue(), A->getSize(),
+ A->getTBAAInfo());
+ if (AA->getModRefInfo(J, ptrLoc) != AliasAnalysis::NoModRef) {
+ UsesI = true;
+ break;
+ }
+ }
+ if (UsesI) break;
+ }
+ }
+ }
+
+ if (UsesI && UpdateUsers) {
+ if (J->mayWriteToMemory()) WriteSet.add(J);
+ Users.insert(J);
+ }
+
+ return UsesI;
+ }
+
+ // This function iterates over all instruction pairs in the provided
+ // basic block and collects all candidate pairs for vectorization.
+ void BBVectorize::getCandidatePairs(BasicBlock &BB,
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts) {
+ BasicBlock::iterator E = BB.end();
+ for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) {
+ bool IsSimpleLoadStore;
+ if (!isInstVectorizable(I, IsSimpleLoadStore)) continue;
+
+ // Look for an instruction with which to pair instruction *I...
+ DenseSet<Value *> Users;
+ AliasSetTracker WriteSet(*AA);
+ BasicBlock::iterator J = I; ++J;
+ for (unsigned ss = 0; J != E && ss <= SearchLimit; ++J, ++ss) {
+ // Determine if J uses I, if so, exit the loop.
+ bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !FastDep);
+ if (FastDep) {
+ // Note: For this heuristic to be effective, independent operations
+ // must tend to be intermixed. This is likely to be true from some
+ // kinds of grouped loop unrolling (but not the generic LLVM pass),
+ // but otherwise may require some kind of reordering pass.
+
+ // When using fast dependency analysis,
+ // stop searching after first use:
+ if (UsesI) break;
+ } else {
+ if (UsesI) continue;
+ }
+
+ // J does not use I, and comes before the first use of I, so it can be
+ // merged with I if the instructions are compatible.
+ if (!areInstsCompatible(I, J, IsSimpleLoadStore)) continue;
+
+ // J is a candidate for merging with I.
+ if (!PairableInsts.size() ||
+ PairableInsts[PairableInsts.size()-1] != I) {
+ PairableInsts.push_back(I);
+ }
+ CandidatePairs.insert(ValuePair(I, J));
+ DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair "
+ << *I << " <-> " << *J << "\n");
+ }
+ }
+
+ DEBUG(dbgs() << "BBV: found " << PairableInsts.size()
+ << " instructions with candidate pairs\n");
+ }
+
+ // Finds candidate pairs connected to the pair P = <PI, PJ>. This means that
+ // it looks for pairs such that both members have an input which is an
+ // output of PI or PJ.
+ void BBVectorize::computePairsConnectedTo(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ ValuePair P) {
+ // For each possible pairing for this variable, look at the uses of
+ // the first value...
+ for (Value::use_iterator I = P.first->use_begin(),
+ E = P.first->use_end(); I != E; ++I) {
+ VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
+
+ // For each use of the first variable, look for uses of the second
+ // variable...
+ for (Value::use_iterator J = P.second->use_begin(),
+ E2 = P.second->use_end(); J != E2; ++J) {
+ VPIteratorPair JPairRange = CandidatePairs.equal_range(*J);
+
+ // Look for <I, J>:
+ if (isSecondInIteratorPair<Value*>(*J, IPairRange))
+ ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J)));
+
+ // Look for <J, I>:
+ if (isSecondInIteratorPair<Value*>(*I, JPairRange))
+ ConnectedPairs.insert(VPPair(P, ValuePair(*J, *I)));
+ }
+
+ if (SplatBreaksChain) continue;
+ // Look for cases where just the first value in the pair is used by
+ // both members of another pair (splatting).
+ for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) {
+ if (isSecondInIteratorPair<Value*>(*J, IPairRange))
+ ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J)));
+ }
+ }
+
+ if (SplatBreaksChain) return;
+ // Look for cases where just the second value in the pair is used by
+ // both members of another pair (splatting).
+ for (Value::use_iterator I = P.second->use_begin(),
+ E = P.second->use_end(); I != E; ++I) {
+ VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
+
+ for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) {
+ if (isSecondInIteratorPair<Value*>(*J, IPairRange))
+ ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J)));
+ }
+ }
+ }
+
+ // This function figures out which pairs are connected. Two pairs are
+ // connected if some output of the first pair forms an input to both members
+ // of the second pair.
+ void BBVectorize::computeConnectedPairs(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs) {
+
+ for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
+ PE = PairableInsts.end(); PI != PE; ++PI) {
+ VPIteratorPair choiceRange = CandidatePairs.equal_range(*PI);
+
+ for (std::multimap<Value *, Value *>::iterator P = choiceRange.first;
+ P != choiceRange.second; ++P)
+ computePairsConnectedTo(CandidatePairs, PairableInsts,
+ ConnectedPairs, *P);
+ }
+
+ DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size()
+ << " pair connections.\n");
+ }
+
+ // This function builds a set of use tuples such that <A, B> is in the set
+ // if B is in the use tree of A. If B is in the use tree of A, then B
+ // depends on the output of A.
+ void BBVectorize::buildDepMap(
+ BasicBlock &BB,
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ DenseSet<ValuePair> &PairableInstUsers) {
+ DenseSet<Value *> IsInPair;
+ for (std::multimap<Value *, Value *>::iterator C = CandidatePairs.begin(),
+ E = CandidatePairs.end(); C != E; ++C) {
+ IsInPair.insert(C->first);
+ IsInPair.insert(C->second);
+ }
+
+ // Iterate through the basic block, recording all Users of each
+ // pairable instruction.
+
+ BasicBlock::iterator E = BB.end();
+ for (BasicBlock::iterator I = BB.getFirstInsertionPt(); I != E; ++I) {
+ if (IsInPair.find(I) == IsInPair.end()) continue;
+
+ DenseSet<Value *> Users;
+ AliasSetTracker WriteSet(*AA);
+ for (BasicBlock::iterator J = llvm::next(I); J != E; ++J)
+ (void) trackUsesOfI(Users, WriteSet, I, J);
+
+ for (DenseSet<Value *>::iterator U = Users.begin(), E = Users.end();
+ U != E; ++U)
+ PairableInstUsers.insert(ValuePair(I, *U));
+ }
+ }
+
+ // Returns true if an input to pair P is an output of pair Q and also an
+ // input of pair Q is an output of pair P. If this is the case, then these
+ // two pairs cannot be simultaneously fused.
+ bool BBVectorize::pairsConflict(ValuePair P, ValuePair Q,
+ DenseSet<ValuePair> &PairableInstUsers,
+ std::multimap<ValuePair, ValuePair> *PairableInstUserMap) {
+ // Two pairs are in conflict if they are mutual Users of eachother.
+ bool QUsesP = PairableInstUsers.count(ValuePair(P.first, Q.first)) ||
+ PairableInstUsers.count(ValuePair(P.first, Q.second)) ||
+ PairableInstUsers.count(ValuePair(P.second, Q.first)) ||
+ PairableInstUsers.count(ValuePair(P.second, Q.second));
+ bool PUsesQ = PairableInstUsers.count(ValuePair(Q.first, P.first)) ||
+ PairableInstUsers.count(ValuePair(Q.first, P.second)) ||
+ PairableInstUsers.count(ValuePair(Q.second, P.first)) ||
+ PairableInstUsers.count(ValuePair(Q.second, P.second));
+ if (PairableInstUserMap) {
+ // FIXME: The expensive part of the cycle check is not so much the cycle
+ // check itself but this edge insertion procedure. This needs some
+ // profiling and probably a different data structure (same is true of
+ // most uses of std::multimap).
+ if (PUsesQ) {
+ VPPIteratorPair QPairRange = PairableInstUserMap->equal_range(Q);
+ if (!isSecondInIteratorPair(P, QPairRange))
+ PairableInstUserMap->insert(VPPair(Q, P));
+ }
+ if (QUsesP) {
+ VPPIteratorPair PPairRange = PairableInstUserMap->equal_range(P);
+ if (!isSecondInIteratorPair(Q, PPairRange))
+ PairableInstUserMap->insert(VPPair(P, Q));
+ }
+ }
+
+ return (QUsesP && PUsesQ);
+ }
+
+ // This function walks the use graph of current pairs to see if, starting
+ // from P, the walk returns to P.
+ bool BBVectorize::pairWillFormCycle(ValuePair P,
+ std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
+ DenseSet<ValuePair> &CurrentPairs) {
+ DEBUG(if (DebugCycleCheck)
+ dbgs() << "BBV: starting cycle check for : " << *P.first << " <-> "
+ << *P.second << "\n");
+ // A lookup table of visisted pairs is kept because the PairableInstUserMap
+ // contains non-direct associations.
+ DenseSet<ValuePair> Visited;
+ std::vector<ValuePair> Q;
+ // General depth-first post-order traversal:
+ Q.push_back(P);
+ while (!Q.empty()) {
+ ValuePair QTop = Q.back();
+
+ Visited.insert(QTop);
+ Q.pop_back();
+
+ DEBUG(if (DebugCycleCheck)
+ dbgs() << "BBV: cycle check visiting: " << *QTop.first << " <-> "
+ << *QTop.second << "\n");
+ VPPIteratorPair QPairRange = PairableInstUserMap.equal_range(QTop);
+ for (std::multimap<ValuePair, ValuePair>::iterator C = QPairRange.first;
+ C != QPairRange.second; ++C) {
+ if (C->second == P) {
+ DEBUG(dbgs()
+ << "BBV: rejected to prevent non-trivial cycle formation: "
+ << *C->first.first << " <-> " << *C->first.second << "\n");
+ return true;
+ }
+
+ if (CurrentPairs.count(C->second) > 0 &&
+ Visited.count(C->second) == 0)
+ Q.push_back(C->second);
+ }
+ }
+
+ return false;
+ }
+
+ // This function builds the initial tree of connected pairs with the
+ // pair J at the root.
+ void BBVectorize::buildInitialTreeFor(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ DenseSet<ValuePair> &PairableInstUsers,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ DenseMap<ValuePair, size_t> &Tree, ValuePair J) {
+ // Each of these pairs is viewed as the root node of a Tree. The Tree
+ // is then walked (depth-first). As this happens, we keep track of
+ // the pairs that compose the Tree and the maximum depth of the Tree.
+ std::vector<ValuePairWithDepth> Q;
+ // General depth-first post-order traversal:
+ Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
+ while (!Q.empty()) {
+ ValuePairWithDepth QTop = Q.back();
+
+ // Push each child onto the queue:
+ bool MoreChildren = false;
+ size_t MaxChildDepth = QTop.second;
+ VPPIteratorPair qtRange = ConnectedPairs.equal_range(QTop.first);
+ for (std::map<ValuePair, ValuePair>::iterator k = qtRange.first;
+ k != qtRange.second; ++k) {
+ // Make sure that this child pair is still a candidate:
+ bool IsStillCand = false;
+ VPIteratorPair checkRange =
+ CandidatePairs.equal_range(k->second.first);
+ for (std::multimap<Value *, Value *>::iterator m = checkRange.first;
+ m != checkRange.second; ++m) {
+ if (m->second == k->second.second) {
+ IsStillCand = true;
+ break;
+ }
+ }
+
+ if (IsStillCand) {
+ DenseMap<ValuePair, size_t>::iterator C = Tree.find(k->second);
+ if (C == Tree.end()) {
+ size_t d = getDepthFactor(k->second.first);
+ Q.push_back(ValuePairWithDepth(k->second, QTop.second+d));
+ MoreChildren = true;
+ } else {
+ MaxChildDepth = std::max(MaxChildDepth, C->second);
+ }
+ }
+ }
+
+ if (!MoreChildren) {
+ // Record the current pair as part of the Tree:
+ Tree.insert(ValuePairWithDepth(QTop.first, MaxChildDepth));
+ Q.pop_back();
+ }
+ }
+ }
+
+ // Given some initial tree, prune it by removing conflicting pairs (pairs
+ // that cannot be simultaneously chosen for vectorization).
+ void BBVectorize::pruneTreeFor(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ DenseSet<ValuePair> &PairableInstUsers,
+ std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ DenseMap<ValuePair, size_t> &Tree,
+ DenseSet<ValuePair> &PrunedTree, ValuePair J,
+ bool UseCycleCheck) {
+ std::vector<ValuePairWithDepth> Q;
+ // General depth-first post-order traversal:
+ Q.push_back(ValuePairWithDepth(J, getDepthFactor(J.first)));
+ while (!Q.empty()) {
+ ValuePairWithDepth QTop = Q.back();
+ PrunedTree.insert(QTop.first);
+ Q.pop_back();
+
+ // Visit each child, pruning as necessary...
+ DenseMap<ValuePair, size_t> BestChilden;
+ VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first);
+ for (std::map<ValuePair, ValuePair>::iterator K = QTopRange.first;
+ K != QTopRange.second; ++K) {
+ DenseMap<ValuePair, size_t>::iterator C = Tree.find(K->second);
+ if (C == Tree.end()) continue;
+
+ // This child is in the Tree, now we need to make sure it is the
+ // best of any conflicting children. There could be multiple
+ // conflicting children, so first, determine if we're keeping
+ // this child, then delete conflicting children as necessary.
+
+ // It is also necessary to guard against pairing-induced
+ // dependencies. Consider instructions a .. x .. y .. b
+ // such that (a,b) are to be fused and (x,y) are to be fused
+ // but a is an input to x and b is an output from y. This
+ // means that y cannot be moved after b but x must be moved
+ // after b for (a,b) to be fused. In other words, after
+ // fusing (a,b) we have y .. a/b .. x where y is an input
+ // to a/b and x is an output to a/b: x and y can no longer
+ // be legally fused. To prevent this condition, we must
+ // make sure that a child pair added to the Tree is not
+ // both an input and output of an already-selected pair.
+
+ // Pairing-induced dependencies can also form from more complicated
+ // cycles. The pair vs. pair conflicts are easy to check, and so
+ // that is done explicitly for "fast rejection", and because for
+ // child vs. child conflicts, we may prefer to keep the current
+ // pair in preference to the already-selected child.
+ DenseSet<ValuePair> CurrentPairs;
+
+ bool CanAdd = true;
+ for (DenseMap<ValuePair, size_t>::iterator C2
+ = BestChilden.begin(), E2 = BestChilden.end();
+ C2 != E2; ++C2) {
+ if (C2->first.first == C->first.first ||
+ C2->first.first == C->first.second ||
+ C2->first.second == C->first.first ||
+ C2->first.second == C->first.second ||
+ pairsConflict(C2->first, C->first, PairableInstUsers,
+ UseCycleCheck ? &PairableInstUserMap : 0)) {
+ if (C2->second >= C->second) {
+ CanAdd = false;
+ break;
+ }
+
+ CurrentPairs.insert(C2->first);
+ }
+ }
+ if (!CanAdd) continue;
+
+ // Even worse, this child could conflict with another node already
+ // selected for the Tree. If that is the case, ignore this child.
+ for (DenseSet<ValuePair>::iterator T = PrunedTree.begin(),
+ E2 = PrunedTree.end(); T != E2; ++T) {
+ if (T->first == C->first.first ||
+ T->first == C->first.second ||
+ T->second == C->first.first ||
+ T->second == C->first.second ||
+ pairsConflict(*T, C->first, PairableInstUsers,
+ UseCycleCheck ? &PairableInstUserMap : 0)) {
+ CanAdd = false;
+ break;
+ }
+
+ CurrentPairs.insert(*T);
+ }
+ if (!CanAdd) continue;
+
+ // And check the queue too...
+ for (std::vector<ValuePairWithDepth>::iterator C2 = Q.begin(),
+ E2 = Q.end(); C2 != E2; ++C2) {
+ if (C2->first.first == C->first.first ||
+ C2->first.first == C->first.second ||
+ C2->first.second == C->first.first ||
+ C2->first.second == C->first.second ||
+ pairsConflict(C2->first, C->first, PairableInstUsers,
+ UseCycleCheck ? &PairableInstUserMap : 0)) {
+ CanAdd = false;
+ break;
+ }
+
+ CurrentPairs.insert(C2->first);
+ }
+ if (!CanAdd) continue;
+
+ // Last but not least, check for a conflict with any of the
+ // already-chosen pairs.
+ for (DenseMap<Value *, Value *>::iterator C2 =
+ ChosenPairs.begin(), E2 = ChosenPairs.end();
+ C2 != E2; ++C2) {
+ if (pairsConflict(*C2, C->first, PairableInstUsers,
+ UseCycleCheck ? &PairableInstUserMap : 0)) {
+ CanAdd = false;
+ break;
+ }
+
+ CurrentPairs.insert(*C2);
+ }
+ if (!CanAdd) continue;
+
+ // To check for non-trivial cycles formed by the addition of the
+ // current pair we've formed a list of all relevant pairs, now use a
+ // graph walk to check for a cycle. We start from the current pair and
+ // walk the use tree to see if we again reach the current pair. If we
+ // do, then the current pair is rejected.
+
+ // FIXME: It may be more efficient to use a topological-ordering
+ // algorithm to improve the cycle check. This should be investigated.
+ if (UseCycleCheck &&
+ pairWillFormCycle(C->first, PairableInstUserMap, CurrentPairs))
+ continue;
+
+ // This child can be added, but we may have chosen it in preference
+ // to an already-selected child. Check for this here, and if a
+ // conflict is found, then remove the previously-selected child
+ // before adding this one in its place.
+ for (DenseMap<ValuePair, size_t>::iterator C2
+ = BestChilden.begin(); C2 != BestChilden.end();) {
+ if (C2->first.first == C->first.first ||
+ C2->first.first == C->first.second ||
+ C2->first.second == C->first.first ||
+ C2->first.second == C->first.second ||
+ pairsConflict(C2->first, C->first, PairableInstUsers))
+ BestChilden.erase(C2++);
+ else
+ ++C2;
+ }
+
+ BestChilden.insert(ValuePairWithDepth(C->first, C->second));
+ }
+
+ for (DenseMap<ValuePair, size_t>::iterator C
+ = BestChilden.begin(), E2 = BestChilden.end();
+ C != E2; ++C) {
+ size_t DepthF = getDepthFactor(C->first.first);
+ Q.push_back(ValuePairWithDepth(C->first, QTop.second+DepthF));
+ }
+ }
+ }
+
+ // This function finds the best tree of mututally-compatible connected
+ // pairs, given the choice of root pairs as an iterator range.
+ void BBVectorize::findBestTreeFor(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ DenseSet<ValuePair> &PairableInstUsers,
+ std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
+ size_t &BestEffSize, VPIteratorPair ChoiceRange,
+ bool UseCycleCheck) {
+ for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first;
+ J != ChoiceRange.second; ++J) {
+
+ // Before going any further, make sure that this pair does not
+ // conflict with any already-selected pairs (see comment below
+ // near the Tree pruning for more details).
+ DenseSet<ValuePair> ChosenPairSet;
+ bool DoesConflict = false;
+ for (DenseMap<Value *, Value *>::iterator C = ChosenPairs.begin(),
+ E = ChosenPairs.end(); C != E; ++C) {
+ if (pairsConflict(*C, *J, PairableInstUsers,
+ UseCycleCheck ? &PairableInstUserMap : 0)) {
+ DoesConflict = true;
+ break;
+ }
+
+ ChosenPairSet.insert(*C);
+ }
+ if (DoesConflict) continue;
+
+ if (UseCycleCheck &&
+ pairWillFormCycle(*J, PairableInstUserMap, ChosenPairSet))
+ continue;
+
+ DenseMap<ValuePair, size_t> Tree;
+ buildInitialTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
+ PairableInstUsers, ChosenPairs, Tree, *J);
+
+ // Because we'll keep the child with the largest depth, the largest
+ // depth is still the same in the unpruned Tree.
+ size_t MaxDepth = Tree.lookup(*J);
+
+ DEBUG(if (DebugPairSelection) dbgs() << "BBV: found Tree for pair {"
+ << *J->first << " <-> " << *J->second << "} of depth " <<
+ MaxDepth << " and size " << Tree.size() << "\n");
+
+ // At this point the Tree has been constructed, but, may contain
+ // contradictory children (meaning that different children of
+ // some tree node may be attempting to fuse the same instruction).
+ // So now we walk the tree again, in the case of a conflict,
+ // keep only the child with the largest depth. To break a tie,
+ // favor the first child.
+
+ DenseSet<ValuePair> PrunedTree;
+ pruneTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
+ PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree,
+ PrunedTree, *J, UseCycleCheck);
+
+ size_t EffSize = 0;
+ for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
+ E = PrunedTree.end(); S != E; ++S)
+ EffSize += getDepthFactor(S->first);
+
+ DEBUG(if (DebugPairSelection)
+ dbgs() << "BBV: found pruned Tree for pair {"
+ << *J->first << " <-> " << *J->second << "} of depth " <<
+ MaxDepth << " and size " << PrunedTree.size() <<
+ " (effective size: " << EffSize << ")\n");
+ if (MaxDepth >= ReqChainDepth && EffSize > BestEffSize) {
+ BestMaxDepth = MaxDepth;
+ BestEffSize = EffSize;
+ BestTree = PrunedTree;
+ }
+ }
+ }
+
+ // Given the list of candidate pairs, this function selects those
+ // that will be fused into vector instructions.
+ void BBVectorize::choosePairs(
+ std::multimap<Value *, Value *> &CandidatePairs,
+ std::vector<Value *> &PairableInsts,
+ std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+ DenseSet<ValuePair> &PairableInstUsers,
+ DenseMap<Value *, Value *>& ChosenPairs) {
+ bool UseCycleCheck = CandidatePairs.size() <= MaxCandPairsForCycleCheck;
+ std::multimap<ValuePair, ValuePair> PairableInstUserMap;
+ for (std::vector<Value *>::iterator I = PairableInsts.begin(),
+ E = PairableInsts.end(); I != E; ++I) {
+ // The number of possible pairings for this variable:
+ size_t NumChoices = CandidatePairs.count(*I);
+ if (!NumChoices) continue;
+
+ VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I);
+
+ // The best pair to choose and its tree:
+ size_t BestMaxDepth = 0, BestEffSize = 0;
+ DenseSet<ValuePair> BestTree;
+ findBestTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
+ PairableInstUsers, PairableInstUserMap, ChosenPairs,
+ BestTree, BestMaxDepth, BestEffSize, ChoiceRange,
+ UseCycleCheck);
+
+ // A tree has been chosen (or not) at this point. If no tree was
+ // chosen, then this instruction, I, cannot be paired (and is no longer
+ // considered).
+
+ DEBUG(if (BestTree.size() > 0)
+ dbgs() << "BBV: selected pairs in the best tree for: "
+ << *cast<Instruction>(*I) << "\n");
+
+ for (DenseSet<ValuePair>::iterator S = BestTree.begin(),
+ SE2 = BestTree.end(); S != SE2; ++S) {
+ // Insert the members of this tree into the list of chosen pairs.
+ ChosenPairs.insert(ValuePair(S->first, S->second));
+ DEBUG(dbgs() << "BBV: selected pair: " << *S->first << " <-> " <<
+ *S->second << "\n");
+
+ // Remove all candidate pairs that have values in the chosen tree.
+ for (std::multimap<Value *, Value *>::iterator K =
+ CandidatePairs.begin(); K != CandidatePairs.end();) {
+ if (K->first == S->first || K->second == S->first ||
+ K->second == S->second || K->first == S->second) {
+ // Don't remove the actual pair chosen so that it can be used
+ // in subsequent tree selections.
+ if (!(K->first == S->first && K->second == S->second))
+ CandidatePairs.erase(K++);
+ else
+ ++K;
+ } else {
+ ++K;
+ }
+ }
+ }
+ }
+
+ DEBUG(dbgs() << "BBV: selected " << ChosenPairs.size() << " pairs.\n");
+ }
+
+ std::string getReplacementName(Instruction *I, bool IsInput, unsigned o,
+ unsigned n = 0) {
+ if (!I->hasName())
+ return "";
+
+ return (I->getName() + (IsInput ? ".v.i" : ".v.r") + utostr(o) +
+ (n > 0 ? "." + utostr(n) : "")).str();
+ }
+
+ // Returns the value that is to be used as the pointer input to the vector
+ // instruction that fuses I with J.
+ Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context,
+ Instruction *I, Instruction *J, unsigned o,
+ bool &FlipMemInputs) {
+ Value *IPtr, *JPtr;
+ unsigned IAlignment, JAlignment;
+ int64_t OffsetInElmts;
+ (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
+ OffsetInElmts);
+
+ // The pointer value is taken to be the one with the lowest offset.
+ Value *VPtr;
+ if (OffsetInElmts > 0) {
+ VPtr = IPtr;
+ } else {
+ FlipMemInputs = true;
+ VPtr = JPtr;
+ }
+
+ Type *ArgType = cast<PointerType>(IPtr->getType())->getElementType();
+ Type *VArgType = getVecTypeForPair(ArgType);
+ Type *VArgPtrType = PointerType::get(VArgType,
+ cast<PointerType>(IPtr->getType())->getAddressSpace());
+ return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o),
+ /* insert before */ FlipMemInputs ? J : I);
+ }
+
+ void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J,
+ unsigned NumElem, unsigned MaskOffset, unsigned NumInElem,
+ unsigned IdxOffset, std::vector<Constant*> &Mask) {
+ for (unsigned v = 0; v < NumElem/2; ++v) {
+ int m = cast<ShuffleVectorInst>(J)->getMaskValue(v);
+ if (m < 0) {
+ Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context));
+ } else {
+ unsigned mm = m + (int) IdxOffset;
+ if (m >= (int) NumInElem)
+ mm += (int) NumInElem;
+
+ Mask[v+MaskOffset] =
+ ConstantInt::get(Type::getInt32Ty(Context), mm);
+ }
+ }
+ }
+
+ // Returns the value that is to be used as the vector-shuffle mask to the
+ // vector instruction that fuses I with J.
+ Value *BBVectorize::getReplacementShuffleMask(LLVMContext& Context,
+ Instruction *I, Instruction *J) {
+ // This is the shuffle mask. We need to append the second
+ // mask to the first, and the numbers need to be adjusted.
+
+ Type *ArgType = I->getType();
+ Type *VArgType = getVecTypeForPair(ArgType);
+
+ // Get the total number of elements in the fused vector type.
+ // By definition, this must equal the number of elements in
+ // the final mask.
+ unsigned NumElem = cast<VectorType>(VArgType)->getNumElements();
+ std::vector<Constant*> Mask(NumElem);
+
+ Type *OpType = I->getOperand(0)->getType();
+ unsigned NumInElem = cast<VectorType>(OpType)->getNumElements();
+
+ // For the mask from the first pair...
+ fillNewShuffleMask(Context, I, NumElem, 0, NumInElem, 0, Mask);
+
+ // For the mask from the second pair...
+ fillNewShuffleMask(Context, J, NumElem, NumElem/2, NumInElem, NumInElem,
+ Mask);
+
+ return ConstantVector::get(Mask);
+ }
+
+ // Returns the value to be used as the specified operand of the vector
+ // instruction that fuses I with J.
+ Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I,
+ Instruction *J, unsigned o, bool FlipMemInputs) {
+ Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
+ Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
+
+ // Compute the fused vector type for this operand
+ Type *ArgType = I->getOperand(o)->getType();
+ VectorType *VArgType = getVecTypeForPair(ArgType);
+
+ Instruction *L = I, *H = J;
+ if (FlipMemInputs) {
+ L = J;
+ H = I;
+ }
+
+ if (ArgType->isVectorTy()) {
+ unsigned numElem = cast<VectorType>(VArgType)->getNumElements();
+ std::vector<Constant*> Mask(numElem);
+ for (unsigned v = 0; v < numElem; ++v)
+ Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
+
+ Instruction *BV = new ShuffleVectorInst(L->getOperand(o),
+ H->getOperand(o),
+ ConstantVector::get(Mask),
+ getReplacementName(I, true, o));
+ BV->insertBefore(J);
+ return BV;
+ }
+
+ // If these two inputs are the output of another vector instruction,
+ // then we should use that output directly. It might be necessary to
+ // permute it first. [When pairings are fused recursively, you can
+ // end up with cases where a large vector is decomposed into scalars
+ // using extractelement instructions, then built into size-2
+ // vectors using insertelement and the into larger vectors using
+ // shuffles. InstCombine does not simplify all of these cases well,
+ // and so we make sure that shuffles are generated here when possible.
+ ExtractElementInst *LEE
+ = dyn_cast<ExtractElementInst>(L->getOperand(o));
+ ExtractElementInst *HEE
+ = dyn_cast<ExtractElementInst>(H->getOperand(o));
+
+ if (LEE && HEE &&
+ LEE->getOperand(0)->getType() == HEE->getOperand(0)->getType()) {
+ VectorType *EEType = cast<VectorType>(LEE->getOperand(0)->getType());
+ unsigned LowIndx = cast<ConstantInt>(LEE->getOperand(1))->getZExtValue();
+ unsigned HighIndx = cast<ConstantInt>(HEE->getOperand(1))->getZExtValue();
+ if (LEE->getOperand(0) == HEE->getOperand(0)) {
+ if (LowIndx == 0 && HighIndx == 1)
+ return LEE->getOperand(0);
+
+ std::vector<Constant*> Mask(2);
+ Mask[0] = ConstantInt::get(Type::getInt32Ty(Context), LowIndx);
+ Mask[1] = ConstantInt::get(Type::getInt32Ty(Context), HighIndx);
+
+ Instruction *BV = new ShuffleVectorInst(LEE->getOperand(0),
+ UndefValue::get(EEType),
+ ConstantVector::get(Mask),
+ getReplacementName(I, true, o));
+ BV->insertBefore(J);
+ return BV;
+ }
+
+ std::vector<Constant*> Mask(2);
+ HighIndx += EEType->getNumElements();
+ Mask[0] = ConstantInt::get(Type::getInt32Ty(Context), LowIndx);
+ Mask[1] = ConstantInt::get(Type::getInt32Ty(Context), HighIndx);
+
+ Instruction *BV = new ShuffleVectorInst(LEE->getOperand(0),
+ HEE->getOperand(0),
+ ConstantVector::get(Mask),
+ getReplacementName(I, true, o));
+ BV->insertBefore(J);
+ return BV;
+ }
+
+ Instruction *BV1 = InsertElementInst::Create(
+ UndefValue::get(VArgType),
+ L->getOperand(o), CV0,
+ getReplacementName(I, true, o, 1));
+ BV1->insertBefore(I);
+ Instruction *BV2 = InsertElementInst::Create(BV1, H->getOperand(o),
+ CV1,
+ getReplacementName(I, true, o, 2));
+ BV2->insertBefore(J);
+ return BV2;
+ }
+
+ // This function creates an array of values that will be used as the inputs
+ // to the vector instruction that fuses I with J.
+ void BBVectorize::getReplacementInputsForPair(LLVMContext& Context,
+ Instruction *I, Instruction *J,
+ SmallVector<Value *, 3> &ReplacedOperands,
+ bool &FlipMemInputs) {
+ FlipMemInputs = false;
+ unsigned NumOperands = I->getNumOperands();
+
+ for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) {
+ // Iterate backward so that we look at the store pointer
+ // first and know whether or not we need to flip the inputs.
+
+ if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) {
+ // This is the pointer for a load/store instruction.
+ ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o,
+ FlipMemInputs);
+ continue;
+ } else if (isa<CallInst>(I) && o == NumOperands-1) {
+ Function *F = cast<CallInst>(I)->getCalledFunction();
+ unsigned IID = F->getIntrinsicID();
+ BasicBlock &BB = *I->getParent();
+
+ Module *M = BB.getParent()->getParent();
+ Type *ArgType = I->getType();
+ Type *VArgType = getVecTypeForPair(ArgType);
+
+ // FIXME: is it safe to do this here?
+ ReplacedOperands[o] = Intrinsic::getDeclaration(M,
+ (Intrinsic::ID) IID, VArgType);
+ continue;
+ } else if (isa<ShuffleVectorInst>(I) && o == NumOperands-1) {
+ ReplacedOperands[o] = getReplacementShuffleMask(Context, I, J);
+ continue;
+ }
+
+ ReplacedOperands[o] =
+ getReplacementInput(Context, I, J, o, FlipMemInputs);
+ }
+ }
+
+ // This function creates two values that represent the outputs of the
+ // original I and J instructions. These are generally vector shuffles
+ // or extracts. In many cases, these will end up being unused and, thus,
+ // eliminated by later passes.
+ void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
+ Instruction *J, Instruction *K,
+ Instruction *&InsertionPt,
+ Instruction *&K1, Instruction *&K2,
+ bool &FlipMemInputs) {
+ Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
+ Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
+
+ if (isa<StoreInst>(I)) {
+ AA->replaceWithNewValue(I, K);
+ AA->replaceWithNewValue(J, K);
+ } else {
+ Type *IType = I->getType();
+ Type *VType = getVecTypeForPair(IType);
+
+ if (IType->isVectorTy()) {
+ unsigned numElem = cast<VectorType>(IType)->getNumElements();
+ std::vector<Constant*> Mask1(numElem), Mask2(numElem);
+ for (unsigned v = 0; v < numElem; ++v) {
+ Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
+ Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElem+v);
+ }
+
+ K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
+ ConstantVector::get(
+ FlipMemInputs ? Mask2 : Mask1),
+ getReplacementName(K, false, 1));
+ K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
+ ConstantVector::get(
+ FlipMemInputs ? Mask1 : Mask2),
+ getReplacementName(K, false, 2));
+ } else {
+ K1 = ExtractElementInst::Create(K, FlipMemInputs ? CV1 : CV0,
+ getReplacementName(K, false, 1));
+ K2 = ExtractElementInst::Create(K, FlipMemInputs ? CV0 : CV1,
+ getReplacementName(K, false, 2));
+ }
+
+ K1->insertAfter(K);
+ K2->insertAfter(K1);
+ InsertionPt = K2;
+ }
+ }
+
+ // Move all uses of the function I (including pairing-induced uses) after J.
+ bool BBVectorize::canMoveUsesOfIAfterJ(BasicBlock &BB,
+ std::multimap<Value *, Value *> &LoadMoveSet,
+ Instruction *I, Instruction *J) {
+ // Skip to the first instruction past I.
+ BasicBlock::iterator L = BB.begin();
+ for (; cast<Instruction>(L) != I; ++L);
+ ++L;
+
+ DenseSet<Value *> Users;
+ AliasSetTracker WriteSet(*AA);
+ for (; cast<Instruction>(L) != J; ++L)
+ (void) trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet);
+
+ assert(cast<Instruction>(L) == J &&
+ "Tracking has not proceeded far enough to check for dependencies");
+ // If J is now in the use set of I, then trackUsesOfI will return true
+ // and we have a dependency cycle (and the fusing operation must abort).
+ return !trackUsesOfI(Users, WriteSet, I, J, true, &LoadMoveSet);
+ }
+
+ // Move all uses of the function I (including pairing-induced uses) after J.
+ void BBVectorize::moveUsesOfIAfterJ(BasicBlock &BB,
+ std::multimap<Value *, Value *> &LoadMoveSet,
+ Instruction *&InsertionPt,
+ Instruction *I, Instruction *J) {
+ // Skip to the first instruction past I.
+ BasicBlock::iterator L = BB.begin();
+ for (; cast<Instruction>(L) != I; ++L);
+ ++L;
+
+ DenseSet<Value *> Users;
+ AliasSetTracker WriteSet(*AA);
+ for (; cast<Instruction>(L) != J;) {
+ if (trackUsesOfI(Users, WriteSet, I, L, true, &LoadMoveSet)) {
+ // Move this instruction
+ Instruction *InstToMove = L; ++L;
+
+ DEBUG(dbgs() << "BBV: moving: " << *InstToMove <<
+ " to after " << *InsertionPt << "\n");
+ InstToMove->removeFromParent();
+ InstToMove->insertAfter(InsertionPt);
+ InsertionPt = InstToMove;
+ } else {
+ ++L;
+ }
+ }
+ }
+
+ // Collect all load instruction that are in the move set of a given first
+ // pair member. These loads depend on the first instruction, I, and so need
+ // to be moved after J (the second instruction) when the pair is fused.
+ void BBVectorize::collectPairLoadMoveSet(BasicBlock &BB,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ std::multimap<Value *, Value *> &LoadMoveSet,
+ Instruction *I) {
+ // Skip to the first instruction past I.
+ BasicBlock::iterator L = BB.begin();
+ for (; cast<Instruction>(L) != I; ++L);
+ ++L;
+
+ DenseSet<Value *> Users;
+ AliasSetTracker WriteSet(*AA);
+
+ // Note: We cannot end the loop when we reach J because J could be moved
+ // farther down the use chain by another instruction pairing. Also, J
+ // could be before I if this is an inverted input.
+ for (BasicBlock::iterator E = BB.end(); cast<Instruction>(L) != E; ++L) {
+ if (trackUsesOfI(Users, WriteSet, I, L)) {
+ if (L->mayReadFromMemory())
+ LoadMoveSet.insert(ValuePair(L, I));
+ }
+ }
+ }
+
+ // In cases where both load/stores and the computation of their pointers
+ // are chosen for vectorization, we can end up in a situation where the
+ // aliasing analysis starts returning different query results as the
+ // process of fusing instruction pairs continues. Because the algorithm
+ // relies on finding the same use trees here as were found earlier, we'll
+ // need to precompute the necessary aliasing information here and then
+ // manually update it during the fusion process.
+ void BBVectorize::collectLoadMoveSet(BasicBlock &BB,
+ std::vector<Value *> &PairableInsts,
+ DenseMap<Value *, Value *> &ChosenPairs,
+ std::multimap<Value *, Value *> &LoadMoveSet) {
+ for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
+ PIE = PairableInsts.end(); PI != PIE; ++PI) {
+ DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI);
+ if (P == ChosenPairs.end()) continue;
+
+ Instruction *I = cast<Instruction>(P->first);
+ collectPairLoadMoveSet(BB, ChosenPairs, LoadMoveSet, I);
+ }
+ }
+
+ // This function fuses the chosen instruction pairs into vector instructions,
+ // taking care preserve any needed scalar outputs and, then, it reorders the
+ // remaining instructions as needed (users of the first member of the pair
+ // need to be moved to after the location of the second member of the pair
+ // because the vector instruction is inserted in the location of the pair's
+ // second member).
+ void BBVectorize::fuseChosenPairs(BasicBlock &BB,
+ std::vector<Value *> &PairableInsts,
+ DenseMap<Value *, Value *> &ChosenPairs) {
+ LLVMContext& Context = BB.getContext();
+
+ // During the vectorization process, the order of the pairs to be fused
+ // could be flipped. So we'll add each pair, flipped, into the ChosenPairs
+ // list. After a pair is fused, the flipped pair is removed from the list.
+ std::vector<ValuePair> FlippedPairs;
+ FlippedPairs.reserve(ChosenPairs.size());
+ for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(),
+ E = ChosenPairs.end(); P != E; ++P)
+ FlippedPairs.push_back(ValuePair(P->second, P->first));
+ for (std::vector<ValuePair>::iterator P = FlippedPairs.begin(),
+ E = FlippedPairs.end(); P != E; ++P)
+ ChosenPairs.insert(*P);
+
+ std::multimap<Value *, Value *> LoadMoveSet;
+ collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet);
+
+ DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n");
+
+ for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) {
+ DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(PI);
+ if (P == ChosenPairs.end()) {
+ ++PI;
+ continue;
+ }
+
+ if (getDepthFactor(P->first) == 0) {
+ // These instructions are not really fused, but are tracked as though
+ // they are. Any case in which it would be interesting to fuse them
+ // will be taken care of by InstCombine.
+ --NumFusedOps;
+ ++PI;
+ continue;
+ }
+
+ Instruction *I = cast<Instruction>(P->first),
+ *J = cast<Instruction>(P->second);
+
+ DEBUG(dbgs() << "BBV: fusing: " << *I <<
+ " <-> " << *J << "\n");
+
+ // Remove the pair and flipped pair from the list.
+ DenseMap<Value *, Value *>::iterator FP = ChosenPairs.find(P->second);
+ assert(FP != ChosenPairs.end() && "Flipped pair not found in list");
+ ChosenPairs.erase(FP);
+ ChosenPairs.erase(P);
+
+ if (!canMoveUsesOfIAfterJ(BB, LoadMoveSet, I, J)) {
+ DEBUG(dbgs() << "BBV: fusion of: " << *I <<
+ " <-> " << *J <<
+ " aborted because of non-trivial dependency cycle\n");
+ --NumFusedOps;
+ ++PI;
+ continue;
+ }
+
+ bool FlipMemInputs;
+ unsigned NumOperands = I->getNumOperands();
+ SmallVector<Value *, 3> ReplacedOperands(NumOperands);
+ getReplacementInputsForPair(Context, I, J, ReplacedOperands,
+ FlipMemInputs);
+
+ // Make a copy of the original operation, change its type to the vector
+ // type and replace its operands with the vector operands.
+ Instruction *K = I->clone();
+ if (I->hasName()) K->takeName(I);
+
+ if (!isa<StoreInst>(K))
+ K->mutateType(getVecTypeForPair(I->getType()));
+
+ for (unsigned o = 0; o < NumOperands; ++o)
+ K->setOperand(o, ReplacedOperands[o]);
+
+ // If we've flipped the memory inputs, make sure that we take the correct
+ // alignment.
+ if (FlipMemInputs) {
+ if (isa<StoreInst>(K))
+ cast<StoreInst>(K)->setAlignment(cast<StoreInst>(J)->getAlignment());
+ else
+ cast<LoadInst>(K)->setAlignment(cast<LoadInst>(J)->getAlignment());
+ }
+
+ K->insertAfter(J);
+
+ // Instruction insertion point:
+ Instruction *InsertionPt = K;
+ Instruction *K1 = 0, *K2 = 0;
+ replaceOutputsOfPair(Context, I, J, K, InsertionPt, K1, K2,
+ FlipMemInputs);
+
+ // The use tree of the first original instruction must be moved to after
+ // the location of the second instruction. The entire use tree of the
+ // first instruction is disjoint from the input tree of the second
+ // (by definition), and so commutes with it.
+
+ moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J);
+
+ if (!isa<StoreInst>(I)) {
+ I->replaceAllUsesWith(K1);
+ J->replaceAllUsesWith(K2);
+ AA->replaceWithNewValue(I, K1);
+ AA->replaceWithNewValue(J, K2);
+ }
+
+ // Instructions that may read from memory may be in the load move set.
+ // Once an instruction is fused, we no longer need its move set, and so
+ // the values of the map never need to be updated. However, when a load
+ // is fused, we need to merge the entries from both instructions in the
+ // pair in case those instructions were in the move set of some other
+ // yet-to-be-fused pair. The loads in question are the keys of the map.
+ if (I->mayReadFromMemory()) {
+ std::vector<ValuePair> NewSetMembers;
+ VPIteratorPair IPairRange = LoadMoveSet.equal_range(I);
+ VPIteratorPair JPairRange = LoadMoveSet.equal_range(J);
+ for (std::multimap<Value *, Value *>::iterator N = IPairRange.first;
+ N != IPairRange.second; ++N)
+ NewSetMembers.push_back(ValuePair(K, N->second));
+ for (std::multimap<Value *, Value *>::iterator N = JPairRange.first;
+ N != JPairRange.second; ++N)
+ NewSetMembers.push_back(ValuePair(K, N->second));
+ for (std::vector<ValuePair>::iterator A = NewSetMembers.begin(),
+ AE = NewSetMembers.end(); A != AE; ++A)
+ LoadMoveSet.insert(*A);
+ }
+
+ // Before removing I, set the iterator to the next instruction.
+ PI = llvm::next(BasicBlock::iterator(I));
+ if (cast<Instruction>(PI) == J)
+ ++PI;
+
+ SE->forgetValue(I);
+ SE->forgetValue(J);
+ I->eraseFromParent();
+ J->eraseFromParent();
+ }
+
+ DEBUG(dbgs() << "BBV: final: \n" << BB << "\n");
+ }
+}
+
+char BBVectorize::ID = 0;
+static const char bb_vectorize_name[] = "Basic-Block Vectorization";
+INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
+INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
+
+BasicBlockPass *llvm::createBBVectorizePass() {
+ return new BBVectorize();
+}
+
diff --git a/lib/Transforms/Vectorize/CMakeLists.txt b/lib/Transforms/Vectorize/CMakeLists.txt
new file mode 100644
index 0000000..4b66930
--- /dev/null
+++ b/lib/Transforms/Vectorize/CMakeLists.txt
@@ -0,0 +1,4 @@
+add_llvm_library(LLVMVectorize
+ BBVectorize.cpp
+ Vectorize.cpp
+ )
diff --git a/lib/Transforms/Vectorize/LLVMBuild.txt b/lib/Transforms/Vectorize/LLVMBuild.txt
new file mode 100644
index 0000000..7167d27
--- /dev/null
+++ b/lib/Transforms/Vectorize/LLVMBuild.txt
@@ -0,0 +1,24 @@
+;===- ./lib/Transforms/Scalar/LLVMBuild.txt --------------------*- Conf -*--===;
+;
+; The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+; http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = Vectorize
+parent = Transforms
+library_name = Vectorize
+required_libraries = Analysis Core InstCombine Support Target TransformUtils
+
diff --git a/lib/Transforms/Vectorize/Makefile b/lib/Transforms/Vectorize/Makefile
new file mode 100644
index 0000000..86c3658
--- /dev/null
+++ b/lib/Transforms/Vectorize/Makefile
@@ -0,0 +1,15 @@
+##===- lib/Transforms/Vectorize/Makefile -----------------*- Makefile -*-===##
+#
+# The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../../..
+LIBRARYNAME = LLVMVectorize
+BUILD_ARCHIVE = 1
+
+include $(LEVEL)/Makefile.common
+
diff --git a/lib/Transforms/Vectorize/Vectorize.cpp b/lib/Transforms/Vectorize/Vectorize.cpp
new file mode 100644
index 0000000..1ef6002
--- /dev/null
+++ b/lib/Transforms/Vectorize/Vectorize.cpp
@@ -0,0 +1,39 @@
+//===-- Vectorize.cpp -----------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// 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.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm-c/Transforms/Vectorize.h"
+#include "llvm-c/Initialization.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/PassManager.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Analysis/Verifier.h"
+#include "llvm/Transforms/Vectorize.h"
+
+using namespace llvm;
+
+/// initializeVectorizationPasses - Initialize all passes linked into the
+/// Vectorization library.
+void llvm::initializeVectorization(PassRegistry &Registry) {
+ initializeBBVectorizePass(Registry);
+}
+
+void LLVMInitializeVectorization(LLVMPassRegistryRef R) {
+ initializeVectorization(*unwrap(R));
+}
+
+void LLVMAddBBVectorizePass(LLVMPassManagerRef PM) {
+ unwrap(PM)->add(createBBVectorizePass());
+}
+