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Diffstat (limited to 'contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp')
| -rw-r--r-- | contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 3547 |
1 files changed, 2555 insertions, 992 deletions
diff --git a/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp index a7ef248..acf2b81 100644 --- a/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -9,10 +9,10 @@ // // This is the LLVM loop vectorizer. This pass modifies 'vectorizable' loops // and generates target-independent LLVM-IR. Legalization of the IR is done -// in the codegen. However, the vectorizes uses (will use) the codegen +// in the codegen. However, the vectorizer uses (will use) the codegen // interfaces to generate IR that is likely to result in an optimal binary. // -// The loop vectorizer combines consecutive loop iteration into a single +// The loop vectorizer combines consecutive loop iterations into a single // 'wide' iteration. After this transformation the index is incremented // by the SIMD vector width, and not by one. // @@ -20,67 +20,107 @@ // 1. The main loop pass that drives the different parts. // 2. LoopVectorizationLegality - A unit that checks for the legality // of the vectorization. -// 3. SingleBlockLoopVectorizer - A unit that performs the actual +// 3. InnerLoopVectorizer - A unit that performs the actual // widening of instructions. // 4. LoopVectorizationCostModel - A unit that checks for the profitability // of vectorization. It decides on the optimal vector width, which // can be one, if vectorization is not profitable. +// //===----------------------------------------------------------------------===// // // The reduction-variable vectorization is based on the paper: // D. Nuzman and R. Henderson. Multi-platform Auto-vectorization. // // Variable uniformity checks are inspired by: -// Karrenberg, R. and Hack, S. Whole Function Vectorization. +// Karrenberg, R. and Hack, S. Whole Function Vectorization. // // Other ideas/concepts are from: // A. Zaks and D. Nuzman. Autovectorization in GCC-two years later. // +// S. Maleki, Y. Gao, M. Garzaran, T. Wong and D. Padua. An Evaluation of +// Vectorizing Compilers. +// //===----------------------------------------------------------------------===// + #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/Analysis/Verifier.h" -#include "llvm/Module.h" -#include "llvm/Type.h" + +#include "llvm/Transforms/Vectorize.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/MapVector.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallSet.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/StringExtras.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/AliasSetTracker.h" -#include "llvm/Analysis/ScalarEvolution.h" #include "llvm/Analysis/Dominators.h" -#include "llvm/Analysis/ScalarEvolutionExpressions.h" -#include "llvm/Analysis/ScalarEvolutionExpander.h" #include "llvm/Analysis/LoopInfo.h" +#include "llvm/Analysis/LoopIterator.h" +#include "llvm/Analysis/LoopPass.h" +#include "llvm/Analysis/ScalarEvolution.h" +#include "llvm/Analysis/ScalarEvolutionExpander.h" +#include "llvm/Analysis/ScalarEvolutionExpressions.h" +#include "llvm/Analysis/TargetTransformInfo.h" #include "llvm/Analysis/ValueTracking.h" -#include "llvm/Transforms/Scalar.h" -#include "llvm/Transforms/Utils/BasicBlockUtils.h" -#include "llvm/TargetTransformInfo.h" +#include "llvm/Analysis/Verifier.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/DerivedTypes.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/IRBuilder.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/Module.h" +#include "llvm/IR/Type.h" +#include "llvm/IR/Value.h" +#include "llvm/Pass.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/raw_ostream.h" -#include "llvm/DataLayout.h" +#include "llvm/Target/TargetLibraryInfo.h" +#include "llvm/Transforms/Scalar.h" +#include "llvm/Transforms/Utils/BasicBlockUtils.h" #include "llvm/Transforms/Utils/Local.h" #include <algorithm> +#include <map> + using namespace llvm; static cl::opt<unsigned> VectorizationFactor("force-vector-width", cl::init(0), cl::Hidden, - cl::desc("Set the default vectorization width. Zero is autoselect.")); + cl::desc("Sets the SIMD width. Zero is autoselect.")); + +static cl::opt<unsigned> +VectorizationUnroll("force-vector-unroll", cl::init(0), cl::Hidden, + cl::desc("Sets the vectorization unroll count. " + "Zero is autoselect.")); + +static cl::opt<bool> +EnableIfConversion("enable-if-conversion", cl::init(true), cl::Hidden, + cl::desc("Enable if-conversion during vectorization.")); /// We don't vectorize loops with a known constant trip count below this number. -const unsigned TinyTripCountThreshold = 16; +static cl::opt<unsigned> +TinyTripCountVectorThreshold("vectorizer-min-trip-count", cl::init(16), + cl::Hidden, + cl::desc("Don't vectorize loops with a constant " + "trip count that is smaller than this " + "value.")); + +/// We don't unroll loops with a known constant trip count below this number. +static const unsigned TinyTripCountUnrollThreshold = 128; /// When performing a runtime memory check, do not check more than this /// number of pointers. Notice that the check is quadratic! -const unsigned RuntimeMemoryCheckThreshold = 2; +static const unsigned RuntimeMemoryCheckThreshold = 4; + +/// We use a metadata with this name to indicate that a scalar loop was +/// vectorized and that we don't need to re-vectorize it if we run into it +/// again. +static const char* +AlreadyVectorizedMDName = "llvm.vectorizer.already_vectorized"; namespace { @@ -88,7 +128,7 @@ namespace { class LoopVectorizationLegality; class LoopVectorizationCostModel; -/// SingleBlockLoopVectorizer vectorizes loops which contain only one basic +/// InnerLoopVectorizer vectorizes loops which contain only one basic /// block to a specified vectorization factor (VF). /// This class performs the widening of scalars into vectors, or multiple /// scalars. This class also implements the following features: @@ -97,36 +137,61 @@ class LoopVectorizationCostModel; /// * It handles the code generation for reduction variables. /// * Scalarization (implementation using scalars) of un-vectorizable /// instructions. -/// SingleBlockLoopVectorizer does not perform any vectorization-legality +/// InnerLoopVectorizer does not perform any vectorization-legality /// checks, and relies on the caller to check for the different legality -/// aspects. The SingleBlockLoopVectorizer relies on the +/// aspects. The InnerLoopVectorizer relies on the /// LoopVectorizationLegality class to provide information about the induction /// and reduction variables that were found to a given vectorization factor. -class SingleBlockLoopVectorizer { +class InnerLoopVectorizer { public: - /// Ctor. - SingleBlockLoopVectorizer(Loop *Orig, ScalarEvolution *Se, LoopInfo *Li, - DominatorTree *dt, LPPassManager *Lpm, - unsigned VecWidth): - OrigLoop(Orig), SE(Se), LI(Li), DT(dt), LPM(Lpm), VF(VecWidth), - Builder(Se->getContext()), Induction(0), OldInduction(0) { } + InnerLoopVectorizer(Loop *OrigLoop, ScalarEvolution *SE, LoopInfo *LI, + DominatorTree *DT, DataLayout *DL, + const TargetLibraryInfo *TLI, unsigned VecWidth, + unsigned UnrollFactor) + : OrigLoop(OrigLoop), SE(SE), LI(LI), DT(DT), DL(DL), TLI(TLI), + VF(VecWidth), UF(UnrollFactor), Builder(SE->getContext()), Induction(0), + OldInduction(0), WidenMap(UnrollFactor) {} // Perform the actual loop widening (vectorization). void vectorize(LoopVectorizationLegality *Legal) { - ///Create a new empty loop. Unlink the old loop and connect the new one. + // Create a new empty loop. Unlink the old loop and connect the new one. createEmptyLoop(Legal); - /// Widen each instruction in the old loop to a new one in the new loop. - /// Use the Legality module to find the induction and reduction variables. + // Widen each instruction in the old loop to a new one in the new loop. + // Use the Legality module to find the induction and reduction variables. vectorizeLoop(Legal); // Register the new loop and update the analysis passes. updateAnalysis(); - } + } private: + /// A small list of PHINodes. + typedef SmallVector<PHINode*, 4> PhiVector; + /// When we unroll loops we have multiple vector values for each scalar. + /// This data structure holds the unrolled and vectorized values that + /// originated from one scalar instruction. + typedef SmallVector<Value*, 2> VectorParts; + + /// Add code that checks at runtime if the accessed arrays overlap. + /// Returns the comparator value or NULL if no check is needed. + Instruction *addRuntimeCheck(LoopVectorizationLegality *Legal, + Instruction *Loc); /// Create an empty loop, based on the loop ranges of the old loop. void createEmptyLoop(LoopVectorizationLegality *Legal); /// Copy and widen the instructions from the old loop. void vectorizeLoop(LoopVectorizationLegality *Legal); + + /// A helper function that computes the predicate of the block BB, assuming + /// that the header block of the loop is set to True. It returns the *entry* + /// mask for the block BB. + VectorParts createBlockInMask(BasicBlock *BB); + /// A helper function that computes the predicate of the edge between SRC + /// and DST. + VectorParts createEdgeMask(BasicBlock *Src, BasicBlock *Dst); + + /// A helper function to vectorize a single BB within the innermost loop. + void vectorizeBlockInLoop(LoopVectorizationLegality *Legal, BasicBlock *BB, + PhiVector *PV); + /// Insert the new loop to the loop hierarchy and pass manager /// and update the analysis passes. void updateAnalysis(); @@ -135,6 +200,10 @@ private: /// of scalars. void scalarizeInstruction(Instruction *Instr); + /// Vectorize Load and Store instructions, + void vectorizeMemoryInstruction(Instruction *Instr, + LoopVectorizationLegality *Legal); + /// 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, ... @@ -142,37 +211,82 @@ private: /// 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); + /// This function adds 0, 1, 2 ... to each vector element, starting at zero. + /// If Negate is set then negative numbers are added e.g. (0, -1, -2, ...). + /// The sequence starts at StartIndex. + Value *getConsecutiveVector(Value* Val, unsigned StartIdx, bool Negate); /// 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); + VectorParts &getVectorValue(Value *V); + + /// Generate a shuffle sequence that will reverse the vector Vec. + Value *reverseVector(Value *Vec); + + /// This is a helper class that holds the vectorizer state. It maps scalar + /// instructions to vector instructions. When the code is 'unrolled' then + /// then a single scalar value is mapped to multiple vector parts. The parts + /// are stored in the VectorPart type. + struct ValueMap { + /// C'tor. UnrollFactor controls the number of vectors ('parts') that + /// are mapped. + ValueMap(unsigned UnrollFactor) : UF(UnrollFactor) {} + + /// \return True if 'Key' is saved in the Value Map. + bool has(Value *Key) const { return MapStorage.count(Key); } + + /// Initializes a new entry in the map. Sets all of the vector parts to the + /// save value in 'Val'. + /// \return A reference to a vector with splat values. + VectorParts &splat(Value *Key, Value *Val) { + VectorParts &Entry = MapStorage[Key]; + Entry.assign(UF, Val); + return Entry; + } - /// Get a uniform vector of constant integers. We use this to get - /// vectors of ones and zeros for the reduction code. - Constant* getUniformVector(unsigned Val, Type* ScalarTy); + ///\return A reference to the value that is stored at 'Key'. + VectorParts &get(Value *Key) { + VectorParts &Entry = MapStorage[Key]; + if (Entry.empty()) + Entry.resize(UF); + assert(Entry.size() == UF); + return Entry; + } - typedef DenseMap<Value*, Value*> ValueMap; + private: + /// The unroll factor. Each entry in the map stores this number of vector + /// elements. + unsigned UF; + + /// Map storage. We use std::map and not DenseMap because insertions to a + /// dense map invalidates its iterators. + std::map<Value *, VectorParts> MapStorage; + }; /// The original loop. Loop *OrigLoop; - // Scev analysis to use. + /// Scev analysis to use. ScalarEvolution *SE; - // Loop Info. + /// Loop Info. LoopInfo *LI; - // Dominator Tree. + /// Dominator Tree. DominatorTree *DT; - // Loop Pass Manager; - LPPassManager *LPM; - // The vectorization factor to use. + /// Data Layout. + DataLayout *DL; + /// Target Library Info. + const TargetLibraryInfo *TLI; + + /// The vectorization SIMD factor to use. Each vector will have this many + /// vector elements. unsigned VF; + /// The vectorization unroll factor to use. Each scalar is vectorized to this + /// many different vector instructions. + unsigned UF; - // The builder that we use + /// The builder that we use IRBuilder<> Builder; // --- Vectorization state --- @@ -189,14 +303,14 @@ private: BasicBlock *LoopVectorBody; ///The scalar loop body. BasicBlock *LoopScalarBody; - ///The first bypass block. - BasicBlock *LoopBypassBlock; + /// A list of all bypass blocks. The first block is the entry of the loop. + SmallVector<BasicBlock *, 4> LoopBypassBlocks; /// The new Induction variable which was added to the new block. PHINode *Induction; /// The induction variable of the old basic block. PHINode *OldInduction; - // Maps scalars to widened vectors. + /// Maps scalars to widened vectors. ValueMap WidenMap; }; @@ -207,36 +321,48 @@ private: /// * Memory checks - The code in canVectorizeMemory checks if vectorization /// will change the order of memory accesses in a way that will change the /// correctness of the program. -/// * Scalars checks - The code in canVectorizeBlock checks for a number -/// of different conditions, such as the availability of a single induction -/// variable, that all types are supported and vectorize-able, etc. -/// This code reflects the capabilities of SingleBlockLoopVectorizer. -/// This class is also used by SingleBlockLoopVectorizer for identifying +/// * Scalars checks - The code in canVectorizeInstrs and canVectorizeMemory +/// checks for a number of different conditions, such as the availability of a +/// single induction variable, that all types are supported and vectorize-able, +/// etc. This code reflects the capabilities of InnerLoopVectorizer. +/// This class is also used by InnerLoopVectorizer for identifying /// induction variable and the different reduction variables. class LoopVectorizationLegality { public: - LoopVectorizationLegality(Loop *Lp, ScalarEvolution *Se, DataLayout *Dl): - TheLoop(Lp), SE(Se), DL(Dl), Induction(0) { } + LoopVectorizationLegality(Loop *L, ScalarEvolution *SE, DataLayout *DL, + DominatorTree *DT, TargetTransformInfo* TTI, + AliasAnalysis *AA, TargetLibraryInfo *TLI) + : TheLoop(L), SE(SE), DL(DL), DT(DT), TTI(TTI), AA(AA), TLI(TLI), + Induction(0) {} - /// This represents the kinds of reductions that we support. + /// This enum represents the kinds of reductions that we support. enum ReductionKind { - NoReduction, /// Not a reduction. - IntegerAdd, /// Sum of numbers. - IntegerMult, /// Product of numbers. - IntegerOr, /// Bitwise or logical OR of numbers. - IntegerAnd, /// Bitwise or logical AND of numbers. - IntegerXor /// Bitwise or logical XOR of numbers. + RK_NoReduction, ///< Not a reduction. + RK_IntegerAdd, ///< Sum of integers. + RK_IntegerMult, ///< Product of integers. + RK_IntegerOr, ///< Bitwise or logical OR of numbers. + RK_IntegerAnd, ///< Bitwise or logical AND of numbers. + RK_IntegerXor, ///< Bitwise or logical XOR of numbers. + RK_FloatAdd, ///< Sum of floats. + RK_FloatMult ///< Product of floats. + }; + + /// This enum represents the kinds of inductions that we support. + enum InductionKind { + IK_NoInduction, ///< Not an induction variable. + IK_IntInduction, ///< Integer induction variable. Step = 1. + IK_ReverseIntInduction, ///< Reverse int induction variable. Step = -1. + IK_PtrInduction, ///< Pointer induction var. Step = sizeof(elem). + IK_ReversePtrInduction ///< Reverse ptr indvar. Step = - sizeof(elem). }; /// This POD struct holds information about reduction variables. struct ReductionDescriptor { - // Default C'tor - ReductionDescriptor(): - StartValue(0), LoopExitInstr(0), Kind(NoReduction) {} + ReductionDescriptor() : StartValue(0), LoopExitInstr(0), + Kind(RK_NoReduction) {} - // C'tor. - ReductionDescriptor(Value *Start, Instruction *Exit, ReductionKind K): - StartValue(Start), LoopExitInstr(Exit), Kind(K) {} + ReductionDescriptor(Value *Start, Instruction *Exit, ReductionKind K) + : StartValue(Start), LoopExitInstr(Exit), Kind(K) {} // The starting value of the reduction. // It does not have to be zero! @@ -250,52 +376,113 @@ public: // This POD struct holds information about the memory runtime legality // check that a group of pointers do not overlap. struct RuntimePointerCheck { + RuntimePointerCheck() : Need(false) {} + + /// Reset the state of the pointer runtime information. + void reset() { + Need = false; + Pointers.clear(); + Starts.clear(); + Ends.clear(); + } + + /// Insert a pointer and calculate the start and end SCEVs. + void insert(ScalarEvolution *SE, Loop *Lp, Value *Ptr); + /// This flag indicates if we need to add the runtime check. bool Need; /// Holds the pointers that we need to check. SmallVector<Value*, 2> Pointers; + /// Holds the pointer value at the beginning of the loop. + SmallVector<const SCEV*, 2> Starts; + /// Holds the pointer value at the end of the loop. + SmallVector<const SCEV*, 2> Ends; + }; + + /// A POD for saving information about induction variables. + struct InductionInfo { + InductionInfo(Value *Start, InductionKind K) : StartValue(Start), IK(K) {} + InductionInfo() : StartValue(0), IK(IK_NoInduction) {} + /// Start value. + Value *StartValue; + /// Induction kind. + InductionKind IK; }; /// ReductionList contains the reduction descriptors for all /// of the reductions that were found in the loop. typedef DenseMap<PHINode*, ReductionDescriptor> ReductionList; + /// InductionList saves induction variables and maps them to the + /// induction descriptor. + typedef MapVector<PHINode*, InductionInfo> InductionList; + + /// Alias(Multi)Map stores the values (GEPs or underlying objects and their + /// respective Store/Load instruction(s) to calculate aliasing. + typedef MapVector<Value*, Instruction* > AliasMap; + typedef DenseMap<Value*, std::vector<Instruction*> > AliasMultiMap; + /// Returns true if it is legal to vectorize this loop. /// This does not mean that it is profitable to vectorize this /// loop, only that it is legal to do so. bool canVectorize(); /// Returns the Induction variable. - PHINode *getInduction() {return Induction;} + PHINode *getInduction() { return Induction; } /// Returns the reduction variables found in the loop. ReductionList *getReductionVars() { return &Reductions; } - /// Check if the pointer returned by this GEP is consecutive - /// when the index is vectorized. This happens when the last - /// index of the GEP is consecutive, like the induction variable. + /// Returns the induction variables found in the loop. + InductionList *getInductionVars() { return &Inductions; } + + /// Returns True if V is an induction variable in this loop. + bool isInductionVariable(const Value *V); + + /// Return true if the block BB needs to be predicated in order for the loop + /// to be vectorized. + bool blockNeedsPredication(BasicBlock *BB); + + /// Check if this pointer is consecutive when vectorizing. This happens + /// when the last index of the GEP is the induction variable, or that the + /// pointer itself is an induction variable. /// This check allows us to vectorize A[idx] into a wide load/store. - bool isConsecutiveGep(Value *Ptr); + /// Returns: + /// 0 - Stride is unknown or non consecutive. + /// 1 - Address is consecutive. + /// -1 - Address is consecutive, and decreasing. + int isConsecutivePtr(Value *Ptr); /// Returns true if the value V is uniform within the loop. bool isUniform(Value *V); /// Returns true if this instruction will remain scalar after vectorization. - bool isUniformAfterVectorization(Instruction* I) {return Uniforms.count(I);} + bool isUniformAfterVectorization(Instruction* I) { return Uniforms.count(I); } /// Returns the information that we collected about runtime memory check. - RuntimePointerCheck *getRuntimePointerCheck() {return &PtrRtCheck; } + RuntimePointerCheck *getRuntimePointerCheck() { return &PtrRtCheck; } 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); + bool canVectorizeInstrs(); /// When we vectorize loops we may change the order in which /// we read and write from memory. This method checks if it is /// legal to vectorize the code, considering only memory constrains. - /// Returns true if BB is vectorizable - bool canVectorizeMemory(BasicBlock &BB); + /// Returns true if the loop is vectorizable + bool canVectorizeMemory(); + + /// Return true if we can vectorize this loop using the IF-conversion + /// transformation. + bool canVectorizeWithIfConvert(); + + /// Collect the variables that need to stay uniform after vectorization. + void collectLoopUniforms(); + + /// Return true if all of the instructions in the block can be speculatively + /// executed. + bool blockCanBePredicated(BasicBlock *BB); /// Returns True, if 'Phi' is the kind of reduction variable for type /// 'Kind'. If this is a reduction variable, it adds it to ReductionList. @@ -303,10 +490,19 @@ private: /// Returns true if the instruction I can be a reduction variable of type /// 'Kind'. bool isReductionInstr(Instruction *I, ReductionKind Kind); - /// Returns True, if 'Phi' is an induction variable. - bool isInductionVariable(PHINode *Phi); + /// Returns the induction kind of Phi. This function may return NoInduction + /// if the PHI is not an induction variable. + InductionKind isInductionVariable(PHINode *Phi); /// Return true if can compute the address bounds of Ptr within the loop. bool hasComputableBounds(Value *Ptr); + /// Return true if there is the chance of write reorder. + bool hasPossibleGlobalWriteReorder(Value *Object, + Instruction *Inst, + AliasMultiMap &WriteObjects, + unsigned MaxByteWidth); + /// Return the AA location for a load or a store. + AliasAnalysis::Location getLoadStoreLocation(Instruction *Inst); + /// The loop that we evaluate. Loop *TheLoop; @@ -314,13 +510,27 @@ private: ScalarEvolution *SE; /// DataLayout analysis. DataLayout *DL; + /// Dominators. + DominatorTree *DT; + /// Target Info. + TargetTransformInfo *TTI; + /// Alias Analysis. + AliasAnalysis *AA; + /// Target Library Info. + TargetLibraryInfo *TLI; // --- vectorization state --- // - /// Holds the induction variable. + /// Holds the integer induction variable. This is the counter of the + /// loop. PHINode *Induction; /// Holds the reduction variables. ReductionList Reductions; + /// Holds all of the induction variables that we found in the loop. + /// Notice that inductions don't need to start at zero and that induction + /// variables can be pointers. + InductionList Inductions; + /// Allowed outside users. This holds the reduction /// vars which can be accessed from outside the loop. SmallPtrSet<Value*, 4> AllowedExit; @@ -334,23 +544,57 @@ private: /// LoopVectorizationCostModel - estimates the expected speedups due to /// vectorization. -/// In many cases vectorization is not profitable. This can happen because -/// of a number of reasons. In this class we mainly attempt to predict -/// the expected speedup/slowdowns due to the supported instruction set. -/// We use the VectorTargetTransformInfo to query the different backends -/// for the cost of different operations. +/// In many cases vectorization is not profitable. This can happen because of +/// a number of reasons. In this class we mainly attempt to predict the +/// expected speedup/slowdowns due to the supported instruction set. We use the +/// TargetTransformInfo to query the different backends for the cost of +/// different operations. class LoopVectorizationCostModel { public: - /// C'tor. - LoopVectorizationCostModel(Loop *Lp, ScalarEvolution *Se, - LoopVectorizationLegality *Leg, - const VectorTargetTransformInfo *Vtti): - TheLoop(Lp), SE(Se), Legal(Leg), VTTI(Vtti) { } + LoopVectorizationCostModel(Loop *L, ScalarEvolution *SE, LoopInfo *LI, + LoopVectorizationLegality *Legal, + const TargetTransformInfo &TTI, + DataLayout *DL, const TargetLibraryInfo *TLI) + : TheLoop(L), SE(SE), LI(LI), Legal(Legal), TTI(TTI), DL(DL), TLI(TLI) {} + + /// Information about vectorization costs + struct VectorizationFactor { + unsigned Width; // Vector width with best cost + unsigned Cost; // Cost of the loop with that width + }; + /// \return The most profitable vectorization factor and the cost of that VF. + /// This method checks every power of two up to VF. If UserVF is not ZERO + /// then this vectorization factor will be selected if vectorization is + /// possible. + VectorizationFactor selectVectorizationFactor(bool OptForSize, + unsigned UserVF); + + /// \return The size (in bits) of the widest type in the code that + /// needs to be vectorized. We ignore values that remain scalar such as + /// 64 bit loop indices. + unsigned getWidestType(); + + /// \return The most profitable unroll factor. + /// If UserUF is non-zero then this method finds the best unroll-factor + /// based on register pressure and other parameters. + /// VF and LoopCost are the selected vectorization factor and the cost of the + /// selected VF. + unsigned selectUnrollFactor(bool OptForSize, unsigned UserUF, unsigned VF, + unsigned LoopCost); + + /// \brief A struct that represents some properties of the register usage + /// of a loop. + struct RegisterUsage { + /// Holds the number of loop invariant values that are used in the loop. + unsigned LoopInvariantRegs; + /// Holds the maximum number of concurrent live intervals in the loop. + unsigned MaxLocalUsers; + /// Holds the number of instructions in the loop. + unsigned NumInstructions; + }; - /// Returns the most profitable vectorization factor for the loop that is - /// smaller or equal to the VF argument. This method checks every power - /// of two up to VF. - unsigned findBestVectorizationFactor(unsigned VF = 8); + /// \return information about the register usage of the loop. + RegisterUsage calculateRegisterUsage(); private: /// Returns the expected execution cost. The unit of the cost does @@ -368,21 +612,32 @@ private: /// the scalar type. static Type* ToVectorTy(Type *Scalar, unsigned VF); + /// Returns whether the instruction is a load or store and will be a emitted + /// as a vector operation. + bool isConsecutiveLoadOrStore(Instruction *I); + /// The loop that we evaluate. Loop *TheLoop; /// Scev analysis. ScalarEvolution *SE; - + /// Loop Info analysis. + LoopInfo *LI; /// Vectorization legality. LoopVectorizationLegality *Legal; /// Vector target information. - const VectorTargetTransformInfo *VTTI; + const TargetTransformInfo &TTI; + /// Target data layout information. + DataLayout *DL; + /// Target Library Info. + const TargetLibraryInfo *TLI; }; +/// The LoopVectorize Pass. struct LoopVectorize : public LoopPass { - static char ID; // Pass identification, replacement for typeid + /// Pass identification, replacement for typeid + static char ID; - LoopVectorize() : LoopPass(ID) { + explicit LoopVectorize() : LoopPass(ID) { initializeLoopVectorizePass(*PassRegistry::getPassRegistry()); } @@ -391,6 +646,8 @@ struct LoopVectorize : public LoopPass { LoopInfo *LI; TargetTransformInfo *TTI; DominatorTree *DT; + AliasAnalysis *AA; + TargetLibraryInfo *TLI; virtual bool runOnLoop(Loop *L, LPPassManager &LPM) { // We only vectorize innermost loops. @@ -400,45 +657,57 @@ struct LoopVectorize : public LoopPass { SE = &getAnalysis<ScalarEvolution>(); DL = getAnalysisIfAvailable<DataLayout>(); LI = &getAnalysis<LoopInfo>(); - TTI = getAnalysisIfAvailable<TargetTransformInfo>(); + TTI = &getAnalysis<TargetTransformInfo>(); DT = &getAnalysis<DominatorTree>(); + AA = getAnalysisIfAvailable<AliasAnalysis>(); + TLI = getAnalysisIfAvailable<TargetLibraryInfo>(); DEBUG(dbgs() << "LV: Checking a loop in \"" << L->getHeader()->getParent()->getName() << "\"\n"); // Check if it is legal to vectorize the loop. - LoopVectorizationLegality LVL(L, SE, DL); + LoopVectorizationLegality LVL(L, SE, DL, DT, TTI, AA, TLI); if (!LVL.canVectorize()) { DEBUG(dbgs() << "LV: Not vectorizing.\n"); return false; } - // Select the preffered vectorization factor. - unsigned VF = 1; - if (VectorizationFactor == 0) { - const VectorTargetTransformInfo *VTTI = 0; - if (TTI) - VTTI = TTI->getVectorTargetTransformInfo(); - // Use the cost model. - LoopVectorizationCostModel CM(L, SE, &LVL, VTTI); - VF = CM.findBestVectorizationFactor(); - - if (VF == 1) { - DEBUG(dbgs() << "LV: Vectorization is possible but not beneficial.\n"); - return false; - } + // Use the cost model. + LoopVectorizationCostModel CM(L, SE, LI, &LVL, *TTI, DL, TLI); + + // Check the function attributes to find out if this function should be + // optimized for size. + Function *F = L->getHeader()->getParent(); + Attribute::AttrKind SzAttr = Attribute::OptimizeForSize; + Attribute::AttrKind FlAttr = Attribute::NoImplicitFloat; + unsigned FnIndex = AttributeSet::FunctionIndex; + bool OptForSize = F->getAttributes().hasAttribute(FnIndex, SzAttr); + bool NoFloat = F->getAttributes().hasAttribute(FnIndex, FlAttr); + + if (NoFloat) { + DEBUG(dbgs() << "LV: Can't vectorize when the NoImplicitFloat" + "attribute is used.\n"); + return false; + } - } else { - // Use the user command flag. - VF = VectorizationFactor; + // Select the optimal vectorization factor. + LoopVectorizationCostModel::VectorizationFactor VF; + VF = CM.selectVectorizationFactor(OptForSize, VectorizationFactor); + // Select the unroll factor. + unsigned UF = CM.selectUnrollFactor(OptForSize, VectorizationUnroll, + VF.Width, VF.Cost); + + if (VF.Width == 1) { + DEBUG(dbgs() << "LV: Vectorization is possible but not beneficial.\n"); + return false; } - DEBUG(dbgs() << "LV: Found a vectorizable loop ("<< VF << ") in "<< - L->getHeader()->getParent()->getParent()->getModuleIdentifier()<< - "\n"); + DEBUG(dbgs() << "LV: Found a vectorizable loop ("<< VF.Width << ") in "<< + F->getParent()->getModuleIdentifier()<<"\n"); + DEBUG(dbgs() << "LV: Unroll Factor is " << UF << "\n"); - // If we decided that it is *legal* to vectorizer the loop then do it. - SingleBlockLoopVectorizer LB(L, SE, LI, DT, &LPM, VF); + // If we decided that it is *legal* to vectorize the loop then do it. + InnerLoopVectorizer LB(L, SE, LI, DT, DL, TLI, VF.Width, UF); LB.vectorize(&LVL); DEBUG(verifyFunction(*L->getHeader()->getParent())); @@ -449,52 +718,75 @@ struct LoopVectorize : public LoopPass { LoopPass::getAnalysisUsage(AU); AU.addRequiredID(LoopSimplifyID); AU.addRequiredID(LCSSAID); + AU.addRequired<DominatorTree>(); AU.addRequired<LoopInfo>(); AU.addRequired<ScalarEvolution>(); - AU.addRequired<DominatorTree>(); + AU.addRequired<TargetTransformInfo>(); AU.addPreserved<LoopInfo>(); AU.addPreserved<DominatorTree>(); } }; -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); +} // end anonymous namespace + +//===----------------------------------------------------------------------===// +// Implementation of LoopVectorizationLegality, InnerLoopVectorizer and +// LoopVectorizationCostModel. +//===----------------------------------------------------------------------===// + +void +LoopVectorizationLegality::RuntimePointerCheck::insert(ScalarEvolution *SE, + Loop *Lp, Value *Ptr) { + const SCEV *Sc = SE->getSCEV(Ptr); + const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Sc); + assert(AR && "Invalid addrec expression"); + const SCEV *Ex = SE->getExitCount(Lp, Lp->getLoopLatch()); + const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE); + Pointers.push_back(Ptr); + Starts.push_back(AR->getStart()); + Ends.push_back(ScEnd); +} + +Value *InnerLoopVectorizer::getBroadcastInstrs(Value *V) { + // Save the current insertion location. + Instruction *Loc = Builder.GetInsertPoint(); + + // We need to place the broadcast of invariant variables outside the loop. + Instruction *Instr = dyn_cast<Instruction>(V); + bool NewInstr = (Instr && Instr->getParent() == LoopVectorBody); + bool Invariant = OrigLoop->isLoopInvariant(V) && !NewInstr; + + // Place the code for broadcasting invariant variables in the new preheader. + if (Invariant) + Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator()); + // 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); + Value *Shuf = Builder.CreateVectorSplat(VF, V, "broadcast"); + + // Restore the builder insertion point. + if (Invariant) + Builder.SetInsertPoint(Loc); + return Shuf; } -Value *SingleBlockLoopVectorizer::getConsecutiveVector(Value* Val) { +Value *InnerLoopVectorizer::getConsecutiveVector(Value* Val, unsigned StartIdx, + bool Negate) { 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<VectorType>(Val->getType()); - unsigned VLen = Ty->getNumElements(); + int VLen = Ty->getNumElements(); SmallVector<Constant*, 8> 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)); + for (int i = 0; i < VLen; ++i) { + int Idx = Negate ? (-i): i; + Indices.push_back(ConstantInt::get(ITy, StartIdx + Idx)); + } // Add the consecutive indices to the vector value. Constant *Cv = ConstantVector::get(Indices); @@ -502,20 +794,58 @@ Value *SingleBlockLoopVectorizer::getConsecutiveVector(Value* Val) { return Builder.CreateAdd(Val, Cv, "induction"); } -bool LoopVectorizationLegality::isConsecutiveGep(Value *Ptr) { +int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) { + assert(Ptr->getType()->isPointerTy() && "Unexpected non ptr"); + // Make sure that the pointer does not point to structs. + if (cast<PointerType>(Ptr->getType())->getElementType()->isAggregateType()) + return 0; + + // If this value is a pointer induction variable we know it is consecutive. + PHINode *Phi = dyn_cast_or_null<PHINode>(Ptr); + if (Phi && Inductions.count(Phi)) { + InductionInfo II = Inductions[Phi]; + if (IK_PtrInduction == II.IK) + return 1; + else if (IK_ReversePtrInduction == II.IK) + return -1; + } + GetElementPtrInst *Gep = dyn_cast_or_null<GetElementPtrInst>(Ptr); if (!Gep) - return false; + return 0; unsigned NumOperands = Gep->getNumOperands(); Value *LastIndex = Gep->getOperand(NumOperands - 1); + Value *GpPtr = Gep->getPointerOperand(); + // If this GEP value is a consecutive pointer induction variable and all of + // the indices are constant then we know it is consecutive. We can + Phi = dyn_cast<PHINode>(GpPtr); + if (Phi && Inductions.count(Phi)) { + + // Make sure that the pointer does not point to structs. + PointerType *GepPtrType = cast<PointerType>(GpPtr->getType()); + if (GepPtrType->getElementType()->isAggregateType()) + return 0; + + // Make sure that all of the index operands are loop invariant. + for (unsigned i = 1; i < NumOperands; ++i) + if (!SE->isLoopInvariant(SE->getSCEV(Gep->getOperand(i)), TheLoop)) + return 0; + + InductionInfo II = Inductions[Phi]; + if (IK_PtrInduction == II.IK) + return 1; + else if (IK_ReversePtrInduction == II.IK) + return -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)), TheLoop)) - return false; + return 0; - // We can emit wide load/stores only of the last index is the induction + // We can emit wide load/stores only if the last index is the induction // variable. const SCEV *Last = SE->getSCEV(LastIndex); if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Last)) { @@ -524,44 +854,153 @@ bool LoopVectorizationLegality::isConsecutiveGep(Value *Ptr) { // The memory is consecutive because the last index is consecutive // and all other indices are loop invariant. if (Step->isOne()) - return true; + return 1; + if (Step->isAllOnesValue()) + return -1; } - return false; + return 0; } bool LoopVectorizationLegality::isUniform(Value *V) { return (SE->isLoopInvariant(SE->getSCEV(V), TheLoop)); } -Value *SingleBlockLoopVectorizer::getVectorValue(Value *V) { +InnerLoopVectorizer::VectorParts& +InnerLoopVectorizer::getVectorValue(Value *V) { + assert(V != Induction && "The new induction variable should not be used."); assert(!V->getType()->isVectorTy() && "Can't widen a vector"); - // If we saved a vectorized copy of V, use it. - Value *&MapEntry = WidenMap[V]; - if (MapEntry) - return MapEntry; - // Broadcast V and save the value for future uses. + // If we have this scalar in the map, return it. + if (WidenMap.has(V)) + return WidenMap.get(V); + + // If this scalar is unknown, assume that it is a constant or that it is + // loop invariant. Broadcast V and save the value for future uses. Value *B = getBroadcastInstrs(V); - MapEntry = B; - return B; + return WidenMap.splat(V, B); } -Constant* -SingleBlockLoopVectorizer::getUniformVector(unsigned Val, Type* ScalarTy) { - SmallVector<Constant*, 8> Indices; - // Create a vector of consecutive numbers from zero to VF. +Value *InnerLoopVectorizer::reverseVector(Value *Vec) { + assert(Vec->getType()->isVectorTy() && "Invalid type"); + SmallVector<Constant*, 8> ShuffleMask; for (unsigned i = 0; i < VF; ++i) - Indices.push_back(ConstantInt::get(ScalarTy, Val, true)); + ShuffleMask.push_back(Builder.getInt32(VF - i - 1)); - // Add the consecutive indices to the vector value. - return ConstantVector::get(Indices); + return Builder.CreateShuffleVector(Vec, UndefValue::get(Vec->getType()), + ConstantVector::get(ShuffleMask), + "reverse"); } -void SingleBlockLoopVectorizer::scalarizeInstruction(Instruction *Instr) { + +void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr, + LoopVectorizationLegality *Legal) { + // Attempt to issue a wide load. + LoadInst *LI = dyn_cast<LoadInst>(Instr); + StoreInst *SI = dyn_cast<StoreInst>(Instr); + + assert((LI || SI) && "Invalid Load/Store instruction"); + + Type *ScalarDataTy = LI ? LI->getType() : SI->getValueOperand()->getType(); + Type *DataTy = VectorType::get(ScalarDataTy, VF); + Value *Ptr = LI ? LI->getPointerOperand() : SI->getPointerOperand(); + unsigned Alignment = LI ? LI->getAlignment() : SI->getAlignment(); + + // If the pointer is loop invariant or if it is non consecutive, + // scalarize the load. + int Stride = Legal->isConsecutivePtr(Ptr); + bool Reverse = Stride < 0; + bool UniformLoad = LI && Legal->isUniform(Ptr); + if (Stride == 0 || UniformLoad) + return scalarizeInstruction(Instr); + + Constant *Zero = Builder.getInt32(0); + VectorParts &Entry = WidenMap.get(Instr); + + // Handle consecutive loads/stores. + GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr); + if (Gep && Legal->isInductionVariable(Gep->getPointerOperand())) { + Value *PtrOperand = Gep->getPointerOperand(); + Value *FirstBasePtr = getVectorValue(PtrOperand)[0]; + FirstBasePtr = Builder.CreateExtractElement(FirstBasePtr, Zero); + + // Create the new GEP with the new induction variable. + GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone()); + Gep2->setOperand(0, FirstBasePtr); + Gep2->setName("gep.indvar.base"); + Ptr = Builder.Insert(Gep2); + } else if (Gep) { + assert(SE->isLoopInvariant(SE->getSCEV(Gep->getPointerOperand()), + OrigLoop) && "Base ptr must be invariant"); + + // The last index does not have to be the induction. It can be + // consecutive and be a function of the index. For example A[I+1]; + unsigned NumOperands = Gep->getNumOperands(); + + Value *LastGepOperand = Gep->getOperand(NumOperands - 1); + VectorParts &GEPParts = getVectorValue(LastGepOperand); + Value *LastIndex = GEPParts[0]; + LastIndex = Builder.CreateExtractElement(LastIndex, Zero); + + // Create the new GEP with the new induction variable. + GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone()); + Gep2->setOperand(NumOperands - 1, LastIndex); + Gep2->setName("gep.indvar.idx"); + Ptr = Builder.Insert(Gep2); + } else { + // Use the induction element ptr. + assert(isa<PHINode>(Ptr) && "Invalid induction ptr"); + VectorParts &PtrVal = getVectorValue(Ptr); + Ptr = Builder.CreateExtractElement(PtrVal[0], Zero); + } + + // Handle Stores: + if (SI) { + assert(!Legal->isUniform(SI->getPointerOperand()) && + "We do not allow storing to uniform addresses"); + + VectorParts &StoredVal = getVectorValue(SI->getValueOperand()); + for (unsigned Part = 0; Part < UF; ++Part) { + // Calculate the pointer for the specific unroll-part. + Value *PartPtr = Builder.CreateGEP(Ptr, Builder.getInt32(Part * VF)); + + if (Reverse) { + // If we store to reverse consecutive memory locations then we need + // to reverse the order of elements in the stored value. + StoredVal[Part] = reverseVector(StoredVal[Part]); + // If the address is consecutive but reversed, then the + // wide store needs to start at the last vector element. + PartPtr = Builder.CreateGEP(Ptr, Builder.getInt32(-Part * VF)); + PartPtr = Builder.CreateGEP(PartPtr, Builder.getInt32(1 - VF)); + } + + Value *VecPtr = Builder.CreateBitCast(PartPtr, DataTy->getPointerTo()); + Builder.CreateStore(StoredVal[Part], VecPtr)->setAlignment(Alignment); + } + } + + for (unsigned Part = 0; Part < UF; ++Part) { + // Calculate the pointer for the specific unroll-part. + Value *PartPtr = Builder.CreateGEP(Ptr, Builder.getInt32(Part * VF)); + + if (Reverse) { + // If the address is consecutive but reversed, then the + // wide store needs to start at the last vector element. + PartPtr = Builder.CreateGEP(Ptr, Builder.getInt32(-Part * VF)); + PartPtr = Builder.CreateGEP(PartPtr, Builder.getInt32(1 - VF)); + } + + Value *VecPtr = Builder.CreateBitCast(PartPtr, DataTy->getPointerTo()); + Value *LI = Builder.CreateLoad(VecPtr, "wide.load"); + cast<LoadInst>(LI)->setAlignment(Alignment); + Entry[Part] = Reverse ? reverseVector(LI) : LI; + } +} + +void InnerLoopVectorizer::scalarizeInstruction(Instruction *Instr) { assert(!Instr->getType()->isAggregateType() && "Can't handle vectors"); // Holds vector parameters or scalars, in case of uniform vals. - SmallVector<Value*, 8> Params; + SmallVector<VectorParts, 4> Params; // Find all of the vectorized parameters. for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) { @@ -569,7 +1008,7 @@ void SingleBlockLoopVectorizer::scalarizeInstruction(Instruction *Instr) { // If we are accessing the old induction variable, use the new one. if (SrcOp == OldInduction) { - Params.push_back(getBroadcastInstrs(Induction)); + Params.push_back(getVectorValue(SrcOp)); continue; } @@ -578,13 +1017,15 @@ void SingleBlockLoopVectorizer::scalarizeInstruction(Instruction *Instr) { // 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"); + if (SrcInst && OrigLoop->contains(SrcInst)) { + assert(WidenMap.has(SrcInst) && "Source operand is unavailable"); // The parameter is a vector value from earlier. - Params.push_back(WidenMap[SrcInst]); + Params.push_back(WidenMap.get(SrcInst)); } else { // The parameter is a scalar from outside the loop. Maybe even a constant. - Params.push_back(SrcOp); + VectorParts Scalars; + Scalars.append(UF, SrcOp); + Params.push_back(Scalars); } } @@ -593,112 +1034,185 @@ void SingleBlockLoopVectorizer::scalarizeInstruction(Instruction *Instr) { // 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)); + Value *UndefVec = IsVoidRetTy ? 0 : + UndefValue::get(VectorType::get(Instr->getType(), VF)); + // Create a new entry in the WidenMap and initialize it to Undef or Null. + VectorParts &VecResults = WidenMap.splat(Instr, UndefVec); // 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); + for (unsigned Width = 0; Width < VF; ++Width) { + // For each vector unroll 'part': + for (unsigned Part = 0; Part < UF; ++Part) { + 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][Part]; + // Param is a vector. Need to extract the right lane. + if (Op->getType()->isVectorTy()) + Op = Builder.CreateExtractElement(Op, Builder.getInt32(Width)); + Cloned->setOperand(op, Op); + } + + // Place the cloned 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[Part] = Builder.CreateInsertElement(VecResults[Part], Cloned, + Builder.getInt32(Width)); + } + } +} + +Instruction * +InnerLoopVectorizer::addRuntimeCheck(LoopVectorizationLegality *Legal, + Instruction *Loc) { + LoopVectorizationLegality::RuntimePointerCheck *PtrRtCheck = + Legal->getRuntimePointerCheck(); + + if (!PtrRtCheck->Need) + return NULL; + + Instruction *MemoryRuntimeCheck = 0; + unsigned NumPointers = PtrRtCheck->Pointers.size(); + SmallVector<Value* , 2> Starts; + SmallVector<Value* , 2> Ends; + + SCEVExpander Exp(*SE, "induction"); + + // Use this type for pointer arithmetic. + Type* PtrArithTy = Type::getInt8PtrTy(Loc->getContext(), 0); + + for (unsigned i = 0; i < NumPointers; ++i) { + Value *Ptr = PtrRtCheck->Pointers[i]; + const SCEV *Sc = SE->getSCEV(Ptr); + + if (SE->isLoopInvariant(Sc, OrigLoop)) { + DEBUG(dbgs() << "LV: Adding RT check for a loop invariant ptr:" << + *Ptr <<"\n"); + Starts.push_back(Ptr); + Ends.push_back(Ptr); + } else { + DEBUG(dbgs() << "LV: Adding RT check for range:" << *Ptr <<"\n"); + + Value *Start = Exp.expandCodeFor(PtrRtCheck->Starts[i], PtrArithTy, Loc); + Value *End = Exp.expandCodeFor(PtrRtCheck->Ends[i], PtrArithTy, Loc); + Starts.push_back(Start); + Ends.push_back(End); } + } + + IRBuilder<> ChkBuilder(Loc); + + for (unsigned i = 0; i < NumPointers; ++i) { + for (unsigned j = i+1; j < NumPointers; ++j) { + Value *Start0 = ChkBuilder.CreateBitCast(Starts[i], PtrArithTy, "bc"); + Value *Start1 = ChkBuilder.CreateBitCast(Starts[j], PtrArithTy, "bc"); + Value *End0 = ChkBuilder.CreateBitCast(Ends[i], PtrArithTy, "bc"); + Value *End1 = ChkBuilder.CreateBitCast(Ends[j], PtrArithTy, "bc"); - // Place the cloned scalar in the new loop. - Builder.Insert(Cloned); + Value *Cmp0 = ChkBuilder.CreateICmpULE(Start0, End1, "bound0"); + Value *Cmp1 = ChkBuilder.CreateICmpULE(Start1, End0, "bound1"); + Value *IsConflict = ChkBuilder.CreateAnd(Cmp0, Cmp1, "found.conflict"); + if (MemoryRuntimeCheck) + IsConflict = ChkBuilder.CreateOr(MemoryRuntimeCheck, IsConflict, + "conflict.rdx"); - // 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)); + MemoryRuntimeCheck = cast<Instruction>(IsConflict); + } } - if (!IsVoidRetTy) - WidenMap[Instr] = VecResults; + return MemoryRuntimeCheck; } void -SingleBlockLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) { +InnerLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) { /* In this function we generate a new loop. The new loop will contain the vectorized instructions while the old loop will continue to run the scalar remainder. - [ ] <-- vector loop bypass. - / | - / v -| [ ] <-- vector pre header. -| | -| v -| [ ] \ -| [ ]_| <-- vector loop. -| | - \ v - >[ ] <--- middle-block. - / | - / v -| [ ] <--- new preheader. -| | -| v -| [ ] \ -| [ ]_| <-- old scalar loop to handle remainder. - \ | - \ v - >[ ] <-- exit block. + [ ] <-- vector loop bypass (may consist of multiple blocks). + / | + / v + | [ ] <-- vector pre header. + | | + | v + | [ ] \ + | [ ]_| <-- vector loop. + | | + \ v + >[ ] <--- middle-block. + / | + / v + | [ ] <--- new preheader. + | | + | v + | [ ] \ + | [ ]_| <-- old scalar loop to handle remainder. + \ | + \ v + >[ ] <-- exit block. ... */ + BasicBlock *OldBasicBlock = OrigLoop->getHeader(); + BasicBlock *BypassBlock = OrigLoop->getLoopPreheader(); + BasicBlock *ExitBlock = OrigLoop->getExitBlock(); + assert(ExitBlock && "Must have an exit block"); + + // Mark the old scalar loop with metadata that tells us not to vectorize this + // loop again if we run into it. + MDNode *MD = MDNode::get(OldBasicBlock->getContext(), ArrayRef<Value*>()); + OldBasicBlock->getTerminator()->setMetadata(AlreadyVectorizedMDName, MD); + + // Some loops have a single integer induction variable, while other loops + // don't. One example is c++ iterators that often have multiple pointer + // induction variables. In the code below we also support a case where we + // don't have a single induction variable. OldInduction = Legal->getInduction(); - assert(OldInduction && "We must have a single phi node."); - Type *IdxTy = OldInduction->getType(); + Type *IdxTy = OldInduction ? OldInduction->getType() : + DL->getIntPtrType(SE->getContext()); // Find the loop boundaries. - const SCEV *ExitCount = SE->getExitCount(OrigLoop, OrigLoop->getHeader()); + const SCEV *ExitCount = SE->getExitCount(OrigLoop, OrigLoop->getLoopLatch()); assert(ExitCount != SE->getCouldNotCompute() && "Invalid loop count"); // Get the total trip count from the count by adding 1. ExitCount = SE->getAddExpr(ExitCount, SE->getConstant(ExitCount->getType(), 1)); - // We may need to extend the index in case there is a type mismatch. - // We know that the count starts at zero and does not overflow. - // We are using Zext because it should be less expensive. - if (ExitCount->getType() != IdxTy) - ExitCount = SE->getZeroExtendExpr(ExitCount, IdxTy); - // This is the original scalar-loop preheader. - BasicBlock *BypassBlock = OrigLoop->getLoopPreheader(); - BasicBlock *ExitBlock = OrigLoop->getExitBlock(); - assert(ExitBlock && "Must have an exit block"); + // 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"); + + // Count holds the overall loop count (N). + Value *Count = Exp.expandCodeFor(ExitCount, ExitCount->getType(), + BypassBlock->getTerminator()); - // The loop index does not have to start at Zero. It starts with this value. - Value *StartIdx = OldInduction->getIncomingValueForBlock(BypassBlock); + // The loop index does not have to start at Zero. Find the original start + // value from the induction PHI node. If we don't have an induction variable + // then we know that it starts at zero. + Value *StartIdx = OldInduction ? + OldInduction->getIncomingValueForBlock(BypassBlock): + ConstantInt::get(IdxTy, 0); - assert(OrigLoop->getNumBlocks() == 1 && "Invalid loop"); assert(BypassBlock && "Invalid loop structure"); + LoopBypassBlocks.push_back(BypassBlock); + // Split the single block loop into the two loop structure described above. BasicBlock *VectorPH = - BypassBlock->splitBasicBlock(BypassBlock->getTerminator(), "vector.ph"); - BasicBlock *VecBody = VectorPH->splitBasicBlock(VectorPH->getTerminator(), - "vector.body"); - - BasicBlock *MiddleBlock = VecBody->splitBasicBlock(VecBody->getTerminator(), - "middle.block"); + BypassBlock->splitBasicBlock(BypassBlock->getTerminator(), "vector.ph"); + BasicBlock *VecBody = + VectorPH->splitBasicBlock(VectorPH->getTerminator(), "vector.body"); + BasicBlock *MiddleBlock = + VecBody->splitBasicBlock(VecBody->getTerminator(), "middle.block"); BasicBlock *ScalarPH = - MiddleBlock->splitBasicBlock(MiddleBlock->getTerminator(), - "scalar.preheader"); - // Find the induction variable. - BasicBlock *OldBasicBlock = OrigLoop->getHeader(); + MiddleBlock->splitBasicBlock(MiddleBlock->getTerminator(), "scalar.ph"); // Use this IR builder to create the loop instructions (Phi, Br, Cmp) // inside the loop. @@ -706,105 +1220,167 @@ SingleBlockLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) { // Generate the induction variable. Induction = Builder.CreatePHI(IdxTy, 2, "index"); - Constant *Step = ConstantInt::get(IdxTy, VF); + // The loop step is equal to the vectorization factor (num of SIMD elements) + // times the unroll factor (num of SIMD instructions). + Constant *Step = ConstantInt::get(IdxTy, VF * UF); - // 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 = BypassBlock->getTerminator(); + // This is the IR builder that we use to add all of the logic for bypassing + // the new vector loop. + IRBuilder<> BypassBuilder(BypassBlock->getTerminator()); - // Count holds the overall loop count (N). - Value *Count = Exp.expandCodeFor(ExitCount, Induction->getType(), Loc); + // We may need to extend the index in case there is a type mismatch. + // We know that the count starts at zero and does not overflow. + if (Count->getType() != IdxTy) { + // The exit count can be of pointer type. Convert it to the correct + // integer type. + if (ExitCount->getType()->isPointerTy()) + Count = BypassBuilder.CreatePointerCast(Count, IdxTy, "ptrcnt.to.int"); + else + Count = BypassBuilder.CreateZExtOrTrunc(Count, IdxTy, "cnt.cast"); + } // Add the start index to the loop count to get the new end index. - Value *IdxEnd = BinaryOperator::CreateAdd(Count, StartIdx, "end.idx", Loc); + Value *IdxEnd = BypassBuilder.CreateAdd(Count, StartIdx, "end.idx"); // Now we need to generate the expression for N - (N % VF), which is // the part that the vectorized body will execute. - Constant *CIVF = ConstantInt::get(IdxTy, VF); - Value *R = BinaryOperator::CreateURem(Count, CIVF, "n.mod.vf", Loc); - Value *CountRoundDown = BinaryOperator::CreateSub(Count, R, "n.vec", Loc); - Value *IdxEndRoundDown = BinaryOperator::CreateAdd(CountRoundDown, StartIdx, - "end.idx.rnd.down", Loc); - - // Now, compare the new count to zero. If it is zero, jump to the scalar part. - Value *Cmp = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, - IdxEndRoundDown, - StartIdx, - "cmp.zero", Loc); + Value *R = BypassBuilder.CreateURem(Count, Step, "n.mod.vf"); + Value *CountRoundDown = BypassBuilder.CreateSub(Count, R, "n.vec"); + Value *IdxEndRoundDown = BypassBuilder.CreateAdd(CountRoundDown, StartIdx, + "end.idx.rnd.down"); + + // Now, compare the new count to zero. If it is zero skip the vector loop and + // jump to the scalar loop. + Value *Cmp = BypassBuilder.CreateICmpEQ(IdxEndRoundDown, StartIdx, + "cmp.zero"); + + BasicBlock *LastBypassBlock = BypassBlock; + + // Generate the code that checks in runtime if arrays overlap. We put the + // checks into a separate block to make the more common case of few elements + // faster. + Instruction *MemRuntimeCheck = addRuntimeCheck(Legal, + BypassBlock->getTerminator()); + if (MemRuntimeCheck) { + // Create a new block containing the memory check. + BasicBlock *CheckBlock = BypassBlock->splitBasicBlock(MemRuntimeCheck, + "vector.memcheck"); + LoopBypassBlocks.push_back(CheckBlock); + + // Replace the branch into the memory check block with a conditional branch + // for the "few elements case". + Instruction *OldTerm = BypassBlock->getTerminator(); + BranchInst::Create(MiddleBlock, CheckBlock, Cmp, OldTerm); + OldTerm->eraseFromParent(); + + Cmp = MemRuntimeCheck; + LastBypassBlock = CheckBlock; + } - LoopVectorizationLegality::RuntimePointerCheck *PtrRtCheck = - Legal->getRuntimePointerCheck(); - Value *MemoryRuntimeCheck = 0; - if (PtrRtCheck->Need) { - unsigned NumPointers = PtrRtCheck->Pointers.size(); - SmallVector<Value* , 2> Starts; - SmallVector<Value* , 2> Ends; - - // Use this type for pointer arithmetic. - Type* PtrArithTy = PtrRtCheck->Pointers[0]->getType(); - - for (unsigned i=0; i < NumPointers; ++i) { - Value *Ptr = PtrRtCheck->Pointers[i]; - const SCEV *Sc = SE->getSCEV(Ptr); - - if (SE->isLoopInvariant(Sc, OrigLoop)) { - DEBUG(dbgs() << "LV1: Adding RT check for a loop invariant ptr:" << - *Ptr <<"\n"); - Starts.push_back(Ptr); - Ends.push_back(Ptr); - } else { - DEBUG(dbgs() << "LV: Adding RT check for range:" << *Ptr <<"\n"); - const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Sc); - Value *Start = Exp.expandCodeFor(AR->getStart(), PtrArithTy, Loc); - const SCEV *Ex = SE->getExitCount(OrigLoop, OrigLoop->getHeader()); - const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE); - assert(!isa<SCEVCouldNotCompute>(ScEnd) && "Invalid scev range."); - Value *End = Exp.expandCodeFor(ScEnd, PtrArithTy, Loc); - Starts.push_back(Start); - Ends.push_back(End); - } - } + LastBypassBlock->getTerminator()->eraseFromParent(); + BranchInst::Create(MiddleBlock, VectorPH, Cmp, + LastBypassBlock); - for (unsigned i=0; i < NumPointers; ++i) { - for (unsigned j=i+1; j < NumPointers; ++j) { - Value *Cmp0 = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_ULE, - Starts[0], Ends[1], "bound0", Loc); - Value *Cmp1 = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_ULE, - Starts[1], Ends[0], "bound1", Loc); - Value *IsConflict = BinaryOperator::Create(Instruction::And, Cmp0, Cmp1, - "found.conflict", Loc); - if (MemoryRuntimeCheck) { - MemoryRuntimeCheck = BinaryOperator::Create(Instruction::Or, - MemoryRuntimeCheck, - IsConflict, - "conflict.rdx", Loc); - } else { - MemoryRuntimeCheck = IsConflict; - } - } + // We are going to resume the execution of the scalar loop. + // Go over all of the induction variables that we found and fix the + // PHIs that are left in the scalar version of the loop. + // The starting values of PHI nodes depend on the counter of the last + // iteration in the vectorized loop. + // If we come from a bypass edge then we need to start from the original + // start value. + + // This variable saves the new starting index for the scalar loop. + PHINode *ResumeIndex = 0; + LoopVectorizationLegality::InductionList::iterator I, E; + LoopVectorizationLegality::InductionList *List = Legal->getInductionVars(); + for (I = List->begin(), E = List->end(); I != E; ++I) { + PHINode *OrigPhi = I->first; + LoopVectorizationLegality::InductionInfo II = I->second; + PHINode *ResumeVal = PHINode::Create(OrigPhi->getType(), 2, "resume.val", + MiddleBlock->getTerminator()); + Value *EndValue = 0; + switch (II.IK) { + case LoopVectorizationLegality::IK_NoInduction: + llvm_unreachable("Unknown induction"); + case LoopVectorizationLegality::IK_IntInduction: { + // Handle the integer induction counter: + assert(OrigPhi->getType()->isIntegerTy() && "Invalid type"); + assert(OrigPhi == OldInduction && "Unknown integer PHI"); + // We know what the end value is. + EndValue = IdxEndRoundDown; + // We also know which PHI node holds it. + ResumeIndex = ResumeVal; + break; + } + case LoopVectorizationLegality::IK_ReverseIntInduction: { + // Convert the CountRoundDown variable to the PHI size. + unsigned CRDSize = CountRoundDown->getType()->getScalarSizeInBits(); + unsigned IISize = II.StartValue->getType()->getScalarSizeInBits(); + Value *CRD = CountRoundDown; + if (CRDSize > IISize) + CRD = CastInst::Create(Instruction::Trunc, CountRoundDown, + II.StartValue->getType(), "tr.crd", + LoopBypassBlocks.back()->getTerminator()); + else if (CRDSize < IISize) + CRD = CastInst::Create(Instruction::SExt, CountRoundDown, + II.StartValue->getType(), + "sext.crd", + LoopBypassBlocks.back()->getTerminator()); + // Handle reverse integer induction counter: + EndValue = + BinaryOperator::CreateSub(II.StartValue, CRD, "rev.ind.end", + LoopBypassBlocks.back()->getTerminator()); + break; + } + case LoopVectorizationLegality::IK_PtrInduction: { + // For pointer induction variables, calculate the offset using + // the end index. + EndValue = + GetElementPtrInst::Create(II.StartValue, CountRoundDown, "ptr.ind.end", + LoopBypassBlocks.back()->getTerminator()); + break; + } + case LoopVectorizationLegality::IK_ReversePtrInduction: { + // The value at the end of the loop for the reverse pointer is calculated + // by creating a GEP with a negative index starting from the start value. + Value *Zero = ConstantInt::get(CountRoundDown->getType(), 0); + Value *NegIdx = BinaryOperator::CreateSub(Zero, CountRoundDown, + "rev.ind.end", + LoopBypassBlocks.back()->getTerminator()); + EndValue = GetElementPtrInst::Create(II.StartValue, NegIdx, + "rev.ptr.ind.end", + LoopBypassBlocks.back()->getTerminator()); + break; } - }// end of need-runtime-check code. + }// end of case - // If we are using memory runtime checks, include them in. - if (MemoryRuntimeCheck) { - Cmp = BinaryOperator::Create(Instruction::Or, Cmp, MemoryRuntimeCheck, - "CntOrMem", Loc); + // The new PHI merges the original incoming value, in case of a bypass, + // or the value at the end of the vectorized loop. + for (unsigned I = 0, E = LoopBypassBlocks.size(); I != E; ++I) + ResumeVal->addIncoming(II.StartValue, LoopBypassBlocks[I]); + ResumeVal->addIncoming(EndValue, VecBody); + + // Fix the scalar body counter (PHI node). + unsigned BlockIdx = OrigPhi->getBasicBlockIndex(ScalarPH); + OrigPhi->setIncomingValue(BlockIdx, ResumeVal); } - BranchInst::Create(MiddleBlock, VectorPH, Cmp, Loc); - // Remove the old terminator. - Loc->eraseFromParent(); + // If we are generating a new induction variable then we also need to + // generate the code that calculates the exit value. This value is not + // simply the end of the counter because we may skip the vectorized body + // in case of a runtime check. + if (!OldInduction){ + assert(!ResumeIndex && "Unexpected resume value found"); + ResumeIndex = PHINode::Create(IdxTy, 2, "new.indc.resume.val", + MiddleBlock->getTerminator()); + for (unsigned I = 0, E = LoopBypassBlocks.size(); I != E; ++I) + ResumeIndex->addIncoming(StartIdx, LoopBypassBlocks[I]); + ResumeIndex->addIncoming(IdxEndRoundDown, VecBody); + } - // We are going to resume the execution of the scalar loop. - // This PHI decides on what number to start. If we come from the - // vector loop then we need to start with the end index minus the - // index modulo VF. If we come from a bypass edge then we need to start - // from the real start. - PHINode* ResumeIndex = PHINode::Create(IdxTy, 2, "resume.idx", - MiddleBlock->getTerminator()); - ResumeIndex->addIncoming(StartIdx, BypassBlock); - ResumeIndex->addIncoming(IdxEndRoundDown, VecBody); + // Make sure that we found the index where scalar loop needs to continue. + assert(ResumeIndex && ResumeIndex->getType()->isIntegerTy() && + "Invalid resume Index"); // Add a check in the middle block to see if we have completed // all of the iterations in the first vector loop. @@ -828,26 +1404,27 @@ SingleBlockLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) { // Now we have two terminators. Remove the old one from the block. VecBody->getTerminator()->eraseFromParent(); - // Fix the scalar body iteration count. - unsigned BlockIdx = OldInduction->getBasicBlockIndex(ScalarPH); - OldInduction->setIncomingValue(BlockIdx, ResumeIndex); - // Get ready to start creating new instructions into the vectorized body. Builder.SetInsertPoint(VecBody->getFirstInsertionPt()); - // Register the new loop. + // Create and register the new vector loop. Loop* Lp = new Loop(); - LPM->insertLoop(Lp, OrigLoop->getParentLoop()); - - Lp->addBasicBlockToLoop(VecBody, LI->getBase()); - Loop *ParentLoop = OrigLoop->getParentLoop(); + + // Insert the new loop into the loop nest and register the new basic blocks. if (ParentLoop) { + ParentLoop->addChildLoop(Lp); + for (unsigned I = 1, E = LoopBypassBlocks.size(); I != E; ++I) + ParentLoop->addBasicBlockToLoop(LoopBypassBlocks[I], LI->getBase()); ParentLoop->addBasicBlockToLoop(ScalarPH, LI->getBase()); ParentLoop->addBasicBlockToLoop(VectorPH, LI->getBase()); ParentLoop->addBasicBlockToLoop(MiddleBlock, LI->getBase()); + } else { + LI->addTopLevelLoop(Lp); } + Lp->addBasicBlockToLoop(VecBody, LI->getBase()); + // Save the state. LoopVectorPreHeader = VectorPH; LoopScalarPreHeader = ScalarPH; @@ -855,32 +1432,164 @@ SingleBlockLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) { LoopExitBlock = ExitBlock; LoopVectorBody = VecBody; LoopScalarBody = OldBasicBlock; - LoopBypassBlock = BypassBlock; } /// This function returns the identity element (or neutral element) for /// the operation K. -static unsigned -getReductionIdentity(LoopVectorizationLegality::ReductionKind K) { +static Constant* +getReductionIdentity(LoopVectorizationLegality::ReductionKind K, Type *Tp) { switch (K) { - case LoopVectorizationLegality::IntegerXor: - case LoopVectorizationLegality::IntegerAdd: - case LoopVectorizationLegality::IntegerOr: + case LoopVectorizationLegality:: RK_IntegerXor: + case LoopVectorizationLegality:: RK_IntegerAdd: + case LoopVectorizationLegality:: RK_IntegerOr: // Adding, Xoring, Oring zero to a number does not change it. - return 0; - case LoopVectorizationLegality::IntegerMult: + return ConstantInt::get(Tp, 0); + case LoopVectorizationLegality:: RK_IntegerMult: // Multiplying a number by 1 does not change it. - return 1; - case LoopVectorizationLegality::IntegerAnd: + return ConstantInt::get(Tp, 1); + case LoopVectorizationLegality:: RK_IntegerAnd: // AND-ing a number with an all-1 value does not change it. - return -1; + return ConstantInt::get(Tp, -1, true); + case LoopVectorizationLegality:: RK_FloatMult: + // Multiplying a number by 1 does not change it. + return ConstantFP::get(Tp, 1.0L); + case LoopVectorizationLegality:: RK_FloatAdd: + // Adding zero to a number does not change it. + return ConstantFP::get(Tp, 0.0L); default: llvm_unreachable("Unknown reduction kind"); } } +static Intrinsic::ID +getIntrinsicIDForCall(CallInst *CI, const TargetLibraryInfo *TLI) { + // If we have an intrinsic call, check if it is trivially vectorizable. + if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI)) { + switch (II->getIntrinsicID()) { + case Intrinsic::sqrt: + case Intrinsic::sin: + case Intrinsic::cos: + case Intrinsic::exp: + case Intrinsic::exp2: + case Intrinsic::log: + case Intrinsic::log10: + case Intrinsic::log2: + case Intrinsic::fabs: + case Intrinsic::floor: + case Intrinsic::ceil: + case Intrinsic::trunc: + case Intrinsic::rint: + case Intrinsic::nearbyint: + case Intrinsic::pow: + case Intrinsic::fma: + case Intrinsic::fmuladd: + return II->getIntrinsicID(); + default: + return Intrinsic::not_intrinsic; + } + } + + if (!TLI) + return Intrinsic::not_intrinsic; + + LibFunc::Func Func; + Function *F = CI->getCalledFunction(); + // We're going to make assumptions on the semantics of the functions, check + // that the target knows that it's available in this environment. + if (!F || !TLI->getLibFunc(F->getName(), Func)) + return Intrinsic::not_intrinsic; + + // Otherwise check if we have a call to a function that can be turned into a + // vector intrinsic. + switch (Func) { + default: + break; + case LibFunc::sin: + case LibFunc::sinf: + case LibFunc::sinl: + return Intrinsic::sin; + case LibFunc::cos: + case LibFunc::cosf: + case LibFunc::cosl: + return Intrinsic::cos; + case LibFunc::exp: + case LibFunc::expf: + case LibFunc::expl: + return Intrinsic::exp; + case LibFunc::exp2: + case LibFunc::exp2f: + case LibFunc::exp2l: + return Intrinsic::exp2; + case LibFunc::log: + case LibFunc::logf: + case LibFunc::logl: + return Intrinsic::log; + case LibFunc::log10: + case LibFunc::log10f: + case LibFunc::log10l: + return Intrinsic::log10; + case LibFunc::log2: + case LibFunc::log2f: + case LibFunc::log2l: + return Intrinsic::log2; + case LibFunc::fabs: + case LibFunc::fabsf: + case LibFunc::fabsl: + return Intrinsic::fabs; + case LibFunc::floor: + case LibFunc::floorf: + case LibFunc::floorl: + return Intrinsic::floor; + case LibFunc::ceil: + case LibFunc::ceilf: + case LibFunc::ceill: + return Intrinsic::ceil; + case LibFunc::trunc: + case LibFunc::truncf: + case LibFunc::truncl: + return Intrinsic::trunc; + case LibFunc::rint: + case LibFunc::rintf: + case LibFunc::rintl: + return Intrinsic::rint; + case LibFunc::nearbyint: + case LibFunc::nearbyintf: + case LibFunc::nearbyintl: + return Intrinsic::nearbyint; + case LibFunc::pow: + case LibFunc::powf: + case LibFunc::powl: + return Intrinsic::pow; + } + + return Intrinsic::not_intrinsic; +} + +/// This function translates the reduction kind to an LLVM binary operator. +static Instruction::BinaryOps +getReductionBinOp(LoopVectorizationLegality::ReductionKind Kind) { + switch (Kind) { + case LoopVectorizationLegality::RK_IntegerAdd: + return Instruction::Add; + case LoopVectorizationLegality::RK_IntegerMult: + return Instruction::Mul; + case LoopVectorizationLegality::RK_IntegerOr: + return Instruction::Or; + case LoopVectorizationLegality::RK_IntegerAnd: + return Instruction::And; + case LoopVectorizationLegality::RK_IntegerXor: + return Instruction::Xor; + case LoopVectorizationLegality::RK_FloatMult: + return Instruction::FMul; + case LoopVectorizationLegality::RK_FloatAdd: + return Instruction::FAdd; + default: + llvm_unreachable("Unknown reduction operation"); + } +} + void -SingleBlockLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) { +InnerLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) { //===------------------------------------------------===// // // Notice: any optimization or new instruction that go @@ -888,208 +1597,29 @@ SingleBlockLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) { // the cost-model. // //===------------------------------------------------===// - typedef SmallVector<PHINode*, 4> PhiVector; - BasicBlock &BB = *OrigLoop->getHeader(); - Constant *Zero = ConstantInt::get( - IntegerType::getInt32Ty(BB.getContext()), 0); + Constant *Zero = Builder.getInt32(0); // In order to support reduction variables we need to be able to vectorize // Phi nodes. Phi nodes have cycles, so we need to vectorize them in two - // steages. First, we create a new vector PHI node with no incoming edges. + // stages. First, we create a new vector PHI node with no incoming edges. // We use this value when we vectorize all of the instructions that use the // PHI. Next, after all of the instructions in the block are complete we // add the new incoming edges to the PHI. At this point all of the // instructions in the basic block are vectorized, so we can use them to // construct the PHI. - PhiVector PHIsToFix; + PhiVector RdxPHIsToFix; - // For each instruction in the old loop. - for (BasicBlock::iterator it = BB.begin(), e = BB.end(); it != e; ++it) { - Instruction *Inst = it; + // Scan the loop in a topological order to ensure that defs are vectorized + // before users. + LoopBlocksDFS DFS(OrigLoop); + DFS.perform(LI); - switch (Inst->getOpcode()) { - case Instruction::Br: - // Nothing to do for PHIs and BR, since we already took care of the - // loop control flow instructions. - continue; - case Instruction::PHI:{ - PHINode* P = cast<PHINode>(Inst); - // Special handling for the induction var. - if (OldInduction == Inst) - continue; - // This is phase one of vectorizing PHIs. - // This has to be a reduction variable. - assert(Legal->getReductionVars()->count(P) && "Not a Reduction"); - Type *VecTy = VectorType::get(Inst->getType(), VF); - WidenMap[Inst] = Builder.CreatePHI(VecTy, 2, "vec.phi"); - PHIsToFix.push_back(P); - 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<BinaryOperator>(Inst); - Value *A = getVectorValue(Inst->getOperand(0)); - Value *B = getVectorValue(Inst->getOperand(1)); - - // Use this vector value for all users of the original instruction. - Value *V = Builder.CreateBinOp(BinOp->getOpcode(), A, B); - WidenMap[Inst] = V; - - // Update the NSW, NUW and Exact flags. - BinaryOperator *VecOp = cast<BinaryOperator>(V); - if (isa<OverflowingBinaryOperator>(BinOp)) { - VecOp->setHasNoSignedWrap(BinOp->hasNoSignedWrap()); - VecOp->setHasNoUnsignedWrap(BinOp->hasNoUnsignedWrap()); - } - if (isa<PossiblyExactOperator>(VecOp)) - VecOp->setIsExact(BinOp->isExact()); - break; - } - case Instruction::Select: { - // Widen selects. - // If the selector is loop invariant we can create a select - // instruction with a scalar condition. Otherwise, use vector-select. - Value *Cond = Inst->getOperand(0); - bool InvariantCond = SE->isLoopInvariant(SE->getSCEV(Cond), OrigLoop); - - // The condition can be loop invariant but still defined inside the - // loop. This means that we can't just use the original 'cond' value. - // We have to take the 'vectorized' value and pick the first lane. - // Instcombine will make this a no-op. - Cond = getVectorValue(Cond); - if (InvariantCond) - Cond = Builder.CreateExtractElement(Cond, Builder.getInt32(0)); - - Value *Op0 = getVectorValue(Inst->getOperand(1)); - Value *Op1 = getVectorValue(Inst->getOperand(2)); - WidenMap[Inst] = Builder.CreateSelect(Cond, Op0, Op1); - break; - } - - case Instruction::ICmp: - case Instruction::FCmp: { - // Widen compares. Generate vector compares. - bool FCmp = (Inst->getOpcode() == Instruction::FCmp); - CmpInst *Cmp = dyn_cast<CmpInst>(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; - } + // Vectorize all of the blocks in the original loop. + for (LoopBlocksDFS::RPOIterator bb = DFS.beginRPO(), + be = DFS.endRPO(); bb != be; ++bb) + vectorizeBlockInLoop(Legal, *bb, &RdxPHIsToFix); - case Instruction::Store: { - // Attempt to issue a wide store. - StoreInst *SI = dyn_cast<StoreInst>(Inst); - Type *StTy = VectorType::get(SI->getValueOperand()->getType(), VF); - Value *Ptr = SI->getPointerOperand(); - unsigned Alignment = SI->getAlignment(); - - assert(!Legal->isUniform(Ptr) && - "We do not allow storing to uniform addresses"); - - GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr); - - // This store does not use GEPs. - if (!Legal->isConsecutiveGep(Gep)) { - scalarizeInstruction(Inst); - break; - } - - // The last index does not have to be the induction. It can be - // consecutive and be a function of the index. For example A[I+1]; - unsigned NumOperands = Gep->getNumOperands(); - Value *LastIndex = getVectorValue(Gep->getOperand(NumOperands - 1)); - LastIndex = Builder.CreateExtractElement(LastIndex, Zero); - - // Create the new GEP with the new induction variable. - GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone()); - Gep2->setOperand(NumOperands - 1, LastIndex); - 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<LoadInst>(Inst); - Type *RetTy = VectorType::get(LI->getType(), VF); - Value *Ptr = LI->getPointerOperand(); - unsigned Alignment = LI->getAlignment(); - GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr); - - // If we don't have a gep, or that the pointer is loop invariant, - // scalarize the load. - if (!Gep || Legal->isUniform(Gep) || !Legal->isConsecutiveGep(Gep)) { - scalarizeInstruction(Inst); - break; - } - - // The last index does not have to be the induction. It can be - // consecutive and be a function of the index. For example A[I+1]; - unsigned NumOperands = Gep->getNumOperands(); - Value *LastIndex = getVectorValue(Gep->getOperand(NumOperands -1)); - LastIndex = Builder.CreateExtractElement(LastIndex, Zero); - - // Create the new GEP with the new induction variable. - GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone()); - Gep2->setOperand(NumOperands - 1, LastIndex); - 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<CastInst>(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. - - // At this point every instruction in the original loop is widended to + // At this point every instruction in the original loop is widened to // a vector form. We are almost done. Now, we need to fix the PHI nodes // that we vectorized. The PHI nodes are currently empty because we did // not want to introduce cycles. Notice that the remaining PHI nodes @@ -1098,38 +1628,36 @@ SingleBlockLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) { // Create the 'reduced' values for each of the induction vars. // The reduced values are the vector values that we scalarize and combine // after the loop is finished. - for (PhiVector::iterator it = PHIsToFix.begin(), e = PHIsToFix.end(); + for (PhiVector::iterator it = RdxPHIsToFix.begin(), e = RdxPHIsToFix.end(); it != e; ++it) { PHINode *RdxPhi = *it; - PHINode *VecRdxPhi = dyn_cast<PHINode>(WidenMap[RdxPhi]); assert(RdxPhi && "Unable to recover vectorized PHI"); // Find the reduction variable descriptor. assert(Legal->getReductionVars()->count(RdxPhi) && "Unable to find the reduction variable"); LoopVectorizationLegality::ReductionDescriptor RdxDesc = - (*Legal->getReductionVars())[RdxPhi]; + (*Legal->getReductionVars())[RdxPhi]; // We need to generate a reduction vector from the incoming scalar. // To do so, we need to generate the 'identity' vector and overide // one of the elements with the incoming scalar reduction. We need // to do it in the vector-loop preheader. - Builder.SetInsertPoint(LoopBypassBlock->getTerminator()); + Builder.SetInsertPoint(LoopBypassBlocks.front()->getTerminator()); // This is the vector-clone of the value that leaves the loop. - Value *VectorExit = getVectorValue(RdxDesc.LoopExitInstr); - Type *VecTy = VectorExit->getType(); + VectorParts &VectorExit = getVectorValue(RdxDesc.LoopExitInstr); + Type *VecTy = VectorExit[0]->getType(); // Find the reduction identity variable. Zero for addition, or, xor, // one for multiplication, -1 for And. - Constant *Identity = getUniformVector(getReductionIdentity(RdxDesc.Kind), - VecTy->getScalarType()); + Constant *Iden = getReductionIdentity(RdxDesc.Kind, VecTy->getScalarType()); + Constant *Identity = ConstantVector::getSplat(VF, Iden); // This vector is the Identity vector where the first element is the // incoming scalar reduction. Value *VectorStart = Builder.CreateInsertElement(Identity, - RdxDesc.StartValue, Zero); - + RdxDesc.StartValue, Zero); // Fix the vector-loop phi. // We created the induction variable so we know that the @@ -1138,10 +1666,17 @@ SingleBlockLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) { // Reductions do not have to start at zero. They can start with // any loop invariant values. - VecRdxPhi->addIncoming(VectorStart, VecPreheader); - unsigned SelfEdgeIdx = (RdxPhi)->getBasicBlockIndex(LoopScalarBody); - Value *Val = getVectorValue(RdxPhi->getIncomingValue(SelfEdgeIdx)); - VecRdxPhi->addIncoming(Val, LoopVectorBody); + VectorParts &VecRdxPhi = WidenMap.get(RdxPhi); + BasicBlock *Latch = OrigLoop->getLoopLatch(); + Value *LoopVal = RdxPhi->getIncomingValueForBlock(Latch); + VectorParts &Val = getVectorValue(LoopVal); + for (unsigned part = 0; part < UF; ++part) { + // Make sure to add the reduction stat value only to the + // first unroll part. + Value *StartVal = (part == 0) ? VectorStart : Identity; + cast<PHINode>(VecRdxPhi[part])->addIncoming(StartVal, VecPreheader); + cast<PHINode>(VecRdxPhi[part])->addIncoming(Val[part], LoopVectorBody); + } // Before each round, move the insertion point right between // the PHIs and the values we are going to write. @@ -1149,40 +1684,56 @@ SingleBlockLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) { // instructions. Builder.SetInsertPoint(LoopMiddleBlock->getFirstInsertionPt()); - // This PHINode contains the vectorized reduction variable, or - // the initial value vector, if we bypass the vector loop. - PHINode *NewPhi = Builder.CreatePHI(VecTy, 2, "rdx.vec.exit.phi"); - NewPhi->addIncoming(VectorStart, LoopBypassBlock); - NewPhi->addIncoming(getVectorValue(RdxDesc.LoopExitInstr), LoopVectorBody); - - // Extract the first scalar. - Value *Scalar0 = - Builder.CreateExtractElement(NewPhi, Builder.getInt32(0)); - // Extract and reduce the remaining vector elements. - for (unsigned i=1; i < VF; ++i) { - Value *Scalar1 = - Builder.CreateExtractElement(NewPhi, Builder.getInt32(i)); - switch (RdxDesc.Kind) { - case LoopVectorizationLegality::IntegerAdd: - Scalar0 = Builder.CreateAdd(Scalar0, Scalar1); - break; - case LoopVectorizationLegality::IntegerMult: - Scalar0 = Builder.CreateMul(Scalar0, Scalar1); - break; - case LoopVectorizationLegality::IntegerOr: - Scalar0 = Builder.CreateOr(Scalar0, Scalar1); - break; - case LoopVectorizationLegality::IntegerAnd: - Scalar0 = Builder.CreateAnd(Scalar0, Scalar1); - break; - case LoopVectorizationLegality::IntegerXor: - Scalar0 = Builder.CreateXor(Scalar0, Scalar1); - break; - default: - llvm_unreachable("Unknown reduction operation"); - } + VectorParts RdxParts; + for (unsigned part = 0; part < UF; ++part) { + // This PHINode contains the vectorized reduction variable, or + // the initial value vector, if we bypass the vector loop. + VectorParts &RdxExitVal = getVectorValue(RdxDesc.LoopExitInstr); + PHINode *NewPhi = Builder.CreatePHI(VecTy, 2, "rdx.vec.exit.phi"); + Value *StartVal = (part == 0) ? VectorStart : Identity; + for (unsigned I = 0, E = LoopBypassBlocks.size(); I != E; ++I) + NewPhi->addIncoming(StartVal, LoopBypassBlocks[I]); + NewPhi->addIncoming(RdxExitVal[part], LoopVectorBody); + RdxParts.push_back(NewPhi); + } + + // Reduce all of the unrolled parts into a single vector. + Value *ReducedPartRdx = RdxParts[0]; + for (unsigned part = 1; part < UF; ++part) { + Instruction::BinaryOps Op = getReductionBinOp(RdxDesc.Kind); + ReducedPartRdx = Builder.CreateBinOp(Op, RdxParts[part], ReducedPartRdx, + "bin.rdx"); } + // VF is a power of 2 so we can emit the reduction using log2(VF) shuffles + // and vector ops, reducing the set of values being computed by half each + // round. + assert(isPowerOf2_32(VF) && + "Reduction emission only supported for pow2 vectors!"); + Value *TmpVec = ReducedPartRdx; + SmallVector<Constant*, 32> ShuffleMask(VF, 0); + for (unsigned i = VF; i != 1; i >>= 1) { + // Move the upper half of the vector to the lower half. + for (unsigned j = 0; j != i/2; ++j) + ShuffleMask[j] = Builder.getInt32(i/2 + j); + + // Fill the rest of the mask with undef. + std::fill(&ShuffleMask[i/2], ShuffleMask.end(), + UndefValue::get(Builder.getInt32Ty())); + + Value *Shuf = + Builder.CreateShuffleVector(TmpVec, + UndefValue::get(TmpVec->getType()), + ConstantVector::get(ShuffleMask), + "rdx.shuf"); + + Instruction::BinaryOps Op = getReductionBinOp(RdxDesc.Kind); + TmpVec = Builder.CreateBinOp(Op, TmpVec, Shuf, "bin.rdx"); + } + + // The result is in the first element of the vector. + Value *Scalar0 = Builder.CreateExtractElement(TmpVec, Builder.getInt32(0)); + // Now, we need to fix the users of the reduction variable // inside and outside of the scalar remainder loop. // We know that the loop is in LCSSA form. We need to update the @@ -1207,24 +1758,378 @@ SingleBlockLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) { // Fix the scalar loop reduction variable with the incoming reduction sum // from the vector body and from the backedge value. - int IncomingEdgeBlockIdx = (RdxPhi)->getBasicBlockIndex(LoopScalarBody); - int SelfEdgeBlockIdx = (IncomingEdgeBlockIdx ? 0 : 1); // The other block. + int IncomingEdgeBlockIdx = + (RdxPhi)->getBasicBlockIndex(OrigLoop->getLoopLatch()); + assert(IncomingEdgeBlockIdx >= 0 && "Invalid block index"); + // Pick the other block. + int SelfEdgeBlockIdx = (IncomingEdgeBlockIdx ? 0 : 1); (RdxPhi)->setIncomingValue(SelfEdgeBlockIdx, Scalar0); (RdxPhi)->setIncomingValue(IncomingEdgeBlockIdx, RdxDesc.LoopExitInstr); }// end of for each redux variable. + + // The Loop exit block may have single value PHI nodes where the incoming + // value is 'undef'. While vectorizing we only handled real values that + // were defined inside the loop. Here we handle the 'undef case'. + // See PR14725. + for (BasicBlock::iterator LEI = LoopExitBlock->begin(), + LEE = LoopExitBlock->end(); LEI != LEE; ++LEI) { + PHINode *LCSSAPhi = dyn_cast<PHINode>(LEI); + if (!LCSSAPhi) continue; + if (LCSSAPhi->getNumIncomingValues() == 1) + LCSSAPhi->addIncoming(UndefValue::get(LCSSAPhi->getType()), + LoopMiddleBlock); + } +} + +InnerLoopVectorizer::VectorParts +InnerLoopVectorizer::createEdgeMask(BasicBlock *Src, BasicBlock *Dst) { + assert(std::find(pred_begin(Dst), pred_end(Dst), Src) != pred_end(Dst) && + "Invalid edge"); + + VectorParts SrcMask = createBlockInMask(Src); + + // The terminator has to be a branch inst! + BranchInst *BI = dyn_cast<BranchInst>(Src->getTerminator()); + assert(BI && "Unexpected terminator found"); + + if (BI->isConditional()) { + VectorParts EdgeMask = getVectorValue(BI->getCondition()); + + if (BI->getSuccessor(0) != Dst) + for (unsigned part = 0; part < UF; ++part) + EdgeMask[part] = Builder.CreateNot(EdgeMask[part]); + + for (unsigned part = 0; part < UF; ++part) + EdgeMask[part] = Builder.CreateAnd(EdgeMask[part], SrcMask[part]); + return EdgeMask; + } + + return SrcMask; +} + +InnerLoopVectorizer::VectorParts +InnerLoopVectorizer::createBlockInMask(BasicBlock *BB) { + assert(OrigLoop->contains(BB) && "Block is not a part of a loop"); + + // Loop incoming mask is all-one. + if (OrigLoop->getHeader() == BB) { + Value *C = ConstantInt::get(IntegerType::getInt1Ty(BB->getContext()), 1); + return getVectorValue(C); + } + + // This is the block mask. We OR all incoming edges, and with zero. + Value *Zero = ConstantInt::get(IntegerType::getInt1Ty(BB->getContext()), 0); + VectorParts BlockMask = getVectorValue(Zero); + + // For each pred: + for (pred_iterator it = pred_begin(BB), e = pred_end(BB); it != e; ++it) { + VectorParts EM = createEdgeMask(*it, BB); + for (unsigned part = 0; part < UF; ++part) + BlockMask[part] = Builder.CreateOr(BlockMask[part], EM[part]); + } + + return BlockMask; +} + +void +InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal, + BasicBlock *BB, PhiVector *PV) { + // For each instruction in the old loop. + for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) { + VectorParts &Entry = WidenMap.get(it); + switch (it->getOpcode()) { + case Instruction::Br: + // Nothing to do for PHIs and BR, since we already took care of the + // loop control flow instructions. + continue; + case Instruction::PHI:{ + PHINode* P = cast<PHINode>(it); + // Handle reduction variables: + if (Legal->getReductionVars()->count(P)) { + for (unsigned part = 0; part < UF; ++part) { + // This is phase one of vectorizing PHIs. + Type *VecTy = VectorType::get(it->getType(), VF); + Entry[part] = PHINode::Create(VecTy, 2, "vec.phi", + LoopVectorBody-> getFirstInsertionPt()); + } + PV->push_back(P); + continue; + } + + // Check for PHI nodes that are lowered to vector selects. + if (P->getParent() != OrigLoop->getHeader()) { + // We know that all PHIs in non header blocks are converted into + // selects, so we don't have to worry about the insertion order and we + // can just use the builder. + + // At this point we generate the predication tree. There may be + // duplications since this is a simple recursive scan, but future + // optimizations will clean it up. + VectorParts Cond = createEdgeMask(P->getIncomingBlock(0), + P->getParent()); + + for (unsigned part = 0; part < UF; ++part) { + VectorParts &In0 = getVectorValue(P->getIncomingValue(0)); + VectorParts &In1 = getVectorValue(P->getIncomingValue(1)); + Entry[part] = Builder.CreateSelect(Cond[part], In0[part], In1[part], + "predphi"); + } + continue; + } + + // This PHINode must be an induction variable. + // Make sure that we know about it. + assert(Legal->getInductionVars()->count(P) && + "Not an induction variable"); + + LoopVectorizationLegality::InductionInfo II = + Legal->getInductionVars()->lookup(P); + + switch (II.IK) { + case LoopVectorizationLegality::IK_NoInduction: + llvm_unreachable("Unknown induction"); + case LoopVectorizationLegality::IK_IntInduction: { + assert(P == OldInduction && "Unexpected PHI"); + Value *Broadcasted = getBroadcastInstrs(Induction); + // After broadcasting the induction variable we need to make the + // vector consecutive by adding 0, 1, 2 ... + for (unsigned part = 0; part < UF; ++part) + Entry[part] = getConsecutiveVector(Broadcasted, VF * part, false); + continue; + } + case LoopVectorizationLegality::IK_ReverseIntInduction: + case LoopVectorizationLegality::IK_PtrInduction: + case LoopVectorizationLegality::IK_ReversePtrInduction: + // Handle reverse integer and pointer inductions. + Value *StartIdx = 0; + // If we have a single integer induction variable then use it. + // Otherwise, start counting at zero. + if (OldInduction) { + LoopVectorizationLegality::InductionInfo OldII = + Legal->getInductionVars()->lookup(OldInduction); + StartIdx = OldII.StartValue; + } else { + StartIdx = ConstantInt::get(Induction->getType(), 0); + } + // This is the normalized GEP that starts counting at zero. + Value *NormalizedIdx = Builder.CreateSub(Induction, StartIdx, + "normalized.idx"); + + // Handle the reverse integer induction variable case. + if (LoopVectorizationLegality::IK_ReverseIntInduction == II.IK) { + IntegerType *DstTy = cast<IntegerType>(II.StartValue->getType()); + Value *CNI = Builder.CreateSExtOrTrunc(NormalizedIdx, DstTy, + "resize.norm.idx"); + Value *ReverseInd = Builder.CreateSub(II.StartValue, CNI, + "reverse.idx"); + + // This is a new value so do not hoist it out. + Value *Broadcasted = getBroadcastInstrs(ReverseInd); + // After broadcasting the induction variable we need to make the + // vector consecutive by adding ... -3, -2, -1, 0. + for (unsigned part = 0; part < UF; ++part) + Entry[part] = getConsecutiveVector(Broadcasted, -VF * part, true); + continue; + } + + // Handle the pointer induction variable case. + assert(P->getType()->isPointerTy() && "Unexpected type."); + + // Is this a reverse induction ptr or a consecutive induction ptr. + bool Reverse = (LoopVectorizationLegality::IK_ReversePtrInduction == + II.IK); + + // This is the vector of results. Notice that we don't generate + // vector geps because scalar geps result in better code. + for (unsigned part = 0; part < UF; ++part) { + Value *VecVal = UndefValue::get(VectorType::get(P->getType(), VF)); + for (unsigned int i = 0; i < VF; ++i) { + int EltIndex = (i + part * VF) * (Reverse ? -1 : 1); + Constant *Idx = ConstantInt::get(Induction->getType(), EltIndex); + Value *GlobalIdx; + if (!Reverse) + GlobalIdx = Builder.CreateAdd(NormalizedIdx, Idx, "gep.idx"); + else + GlobalIdx = Builder.CreateSub(Idx, NormalizedIdx, "gep.ridx"); + + Value *SclrGep = Builder.CreateGEP(II.StartValue, GlobalIdx, + "next.gep"); + VecVal = Builder.CreateInsertElement(VecVal, SclrGep, + Builder.getInt32(i), + "insert.gep"); + } + Entry[part] = VecVal; + } + continue; + } + + }// End of PHI. + + 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<BinaryOperator>(it); + VectorParts &A = getVectorValue(it->getOperand(0)); + VectorParts &B = getVectorValue(it->getOperand(1)); + + // Use this vector value for all users of the original instruction. + for (unsigned Part = 0; Part < UF; ++Part) { + Value *V = Builder.CreateBinOp(BinOp->getOpcode(), A[Part], B[Part]); + + // Update the NSW, NUW and Exact flags. Notice: V can be an Undef. + BinaryOperator *VecOp = dyn_cast<BinaryOperator>(V); + if (VecOp && isa<OverflowingBinaryOperator>(BinOp)) { + VecOp->setHasNoSignedWrap(BinOp->hasNoSignedWrap()); + VecOp->setHasNoUnsignedWrap(BinOp->hasNoUnsignedWrap()); + } + if (VecOp && isa<PossiblyExactOperator>(VecOp)) + VecOp->setIsExact(BinOp->isExact()); + + Entry[Part] = V; + } + break; + } + case Instruction::Select: { + // Widen selects. + // If the selector is loop invariant we can create a select + // instruction with a scalar condition. Otherwise, use vector-select. + bool InvariantCond = SE->isLoopInvariant(SE->getSCEV(it->getOperand(0)), + OrigLoop); + + // The condition can be loop invariant but still defined inside the + // loop. This means that we can't just use the original 'cond' value. + // We have to take the 'vectorized' value and pick the first lane. + // Instcombine will make this a no-op. + VectorParts &Cond = getVectorValue(it->getOperand(0)); + VectorParts &Op0 = getVectorValue(it->getOperand(1)); + VectorParts &Op1 = getVectorValue(it->getOperand(2)); + Value *ScalarCond = Builder.CreateExtractElement(Cond[0], + Builder.getInt32(0)); + for (unsigned Part = 0; Part < UF; ++Part) { + Entry[Part] = Builder.CreateSelect( + InvariantCond ? ScalarCond : Cond[Part], + Op0[Part], + Op1[Part]); + } + break; + } + + case Instruction::ICmp: + case Instruction::FCmp: { + // Widen compares. Generate vector compares. + bool FCmp = (it->getOpcode() == Instruction::FCmp); + CmpInst *Cmp = dyn_cast<CmpInst>(it); + VectorParts &A = getVectorValue(it->getOperand(0)); + VectorParts &B = getVectorValue(it->getOperand(1)); + for (unsigned Part = 0; Part < UF; ++Part) { + Value *C = 0; + if (FCmp) + C = Builder.CreateFCmp(Cmp->getPredicate(), A[Part], B[Part]); + else + C = Builder.CreateICmp(Cmp->getPredicate(), A[Part], B[Part]); + Entry[Part] = C; + } + break; + } + + case Instruction::Store: + case Instruction::Load: + vectorizeMemoryInstruction(it, Legal); + 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: { + CastInst *CI = dyn_cast<CastInst>(it); + /// Optimize the special case where the source is the induction + /// variable. Notice that we can only optimize the 'trunc' case + /// because: a. FP conversions lose precision, b. sext/zext may wrap, + /// c. other casts depend on pointer size. + if (CI->getOperand(0) == OldInduction && + it->getOpcode() == Instruction::Trunc) { + Value *ScalarCast = Builder.CreateCast(CI->getOpcode(), Induction, + CI->getType()); + Value *Broadcasted = getBroadcastInstrs(ScalarCast); + for (unsigned Part = 0; Part < UF; ++Part) + Entry[Part] = getConsecutiveVector(Broadcasted, VF * Part, false); + break; + } + /// Vectorize casts. + Type *DestTy = VectorType::get(CI->getType()->getScalarType(), VF); + + VectorParts &A = getVectorValue(it->getOperand(0)); + for (unsigned Part = 0; Part < UF; ++Part) + Entry[Part] = Builder.CreateCast(CI->getOpcode(), A[Part], DestTy); + break; + } + + case Instruction::Call: { + // Ignore dbg intrinsics. + if (isa<DbgInfoIntrinsic>(it)) + break; + + Module *M = BB->getParent()->getParent(); + CallInst *CI = cast<CallInst>(it); + Intrinsic::ID ID = getIntrinsicIDForCall(CI, TLI); + assert(ID && "Not an intrinsic call!"); + for (unsigned Part = 0; Part < UF; ++Part) { + SmallVector<Value*, 4> Args; + for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) { + VectorParts &Arg = getVectorValue(CI->getArgOperand(i)); + Args.push_back(Arg[Part]); + } + Type *Tys[] = { VectorType::get(CI->getType()->getScalarType(), VF) }; + Function *F = Intrinsic::getDeclaration(M, ID, Tys); + Entry[Part] = Builder.CreateCall(F, Args); + } + break; + } + + default: + // All other instructions are unsupported. Scalarize them. + scalarizeInstruction(it); + break; + }// end of switch. + }// end of for_each instr. } -void SingleBlockLoopVectorizer::updateAnalysis() { - // The original basic block. +void InnerLoopVectorizer::updateAnalysis() { + // Forget the original basic block. SE->forgetLoop(OrigLoop); // Update the dominator tree information. - assert(DT->properlyDominates(LoopBypassBlock, LoopExitBlock) && + assert(DT->properlyDominates(LoopBypassBlocks.front(), LoopExitBlock) && "Entry does not dominate exit."); - DT->addNewBlock(LoopVectorPreHeader, LoopBypassBlock); + for (unsigned I = 1, E = LoopBypassBlocks.size(); I != E; ++I) + DT->addNewBlock(LoopBypassBlocks[I], LoopBypassBlocks[I-1]); + DT->addNewBlock(LoopVectorPreHeader, LoopBypassBlocks.back()); DT->addNewBlock(LoopVectorBody, LoopVectorPreHeader); - DT->addNewBlock(LoopMiddleBlock, LoopBypassBlock); + DT->addNewBlock(LoopMiddleBlock, LoopBypassBlocks.front()); DT->addNewBlock(LoopScalarPreHeader, LoopMiddleBlock); DT->changeImmediateDominator(LoopScalarBody, LoopScalarPreHeader); DT->changeImmediateDominator(LoopExitBlock, LoopMiddleBlock); @@ -1232,45 +2137,94 @@ void SingleBlockLoopVectorizer::updateAnalysis() { DEBUG(DT->verifyAnalysis()); } -bool LoopVectorizationLegality::canVectorize() { - if (!TheLoop->getLoopPreheader()) { - assert(false && "No preheader!!"); - DEBUG(dbgs() << "LV: Loop not normalized." << "\n"); - return false; +bool LoopVectorizationLegality::canVectorizeWithIfConvert() { + if (!EnableIfConversion) + return false; + + assert(TheLoop->getNumBlocks() > 1 && "Single block loops are vectorizable"); + std::vector<BasicBlock*> &LoopBlocks = TheLoop->getBlocksVector(); + + // Collect the blocks that need predication. + for (unsigned i = 0, e = LoopBlocks.size(); i < e; ++i) { + BasicBlock *BB = LoopBlocks[i]; + + // We don't support switch statements inside loops. + if (!isa<BranchInst>(BB->getTerminator())) + return false; + + // We must have at most two predecessors because we need to convert + // all PHIs to selects. + unsigned Preds = std::distance(pred_begin(BB), pred_end(BB)); + if (Preds > 2) + return false; + + // We must be able to predicate all blocks that need to be predicated. + if (blockNeedsPredication(BB) && !blockCanBePredicated(BB)) + return false; } - // We can only vectorize single basic block loops. + // We can if-convert this loop. + return true; +} + +bool LoopVectorizationLegality::canVectorize() { + assert(TheLoop->getLoopPreheader() && "No preheader!!"); + + // We can only vectorize innermost loops. + if (TheLoop->getSubLoopsVector().size()) + return false; + + // We must have a single backedge. + if (TheLoop->getNumBackEdges() != 1) + return false; + + // We must have a single exiting block. + if (!TheLoop->getExitingBlock()) + return false; + unsigned NumBlocks = TheLoop->getNumBlocks(); - if (NumBlocks != 1) { - DEBUG(dbgs() << "LV: Too many blocks:" << NumBlocks << "\n"); + + // Check if we can if-convert non single-bb loops. + if (NumBlocks != 1 && !canVectorizeWithIfConvert()) { + DEBUG(dbgs() << "LV: Can't if-convert the loop.\n"); return false; } // We need to have a loop header. - BasicBlock *BB = TheLoop->getHeader(); - DEBUG(dbgs() << "LV: Found a loop: " << BB->getName() << "\n"); + BasicBlock *Latch = TheLoop->getLoopLatch(); + DEBUG(dbgs() << "LV: Found a loop: " << + TheLoop->getHeader()->getName() << "\n"); // ScalarEvolution needs to be able to find the exit count. - const SCEV *ExitCount = SE->getExitCount(TheLoop, BB); + const SCEV *ExitCount = SE->getExitCount(TheLoop, Latch); if (ExitCount == SE->getCouldNotCompute()) { DEBUG(dbgs() << "LV: SCEV could not compute the loop exit count.\n"); return false; } // Do not loop-vectorize loops with a tiny trip count. - unsigned TC = SE->getSmallConstantTripCount(TheLoop, BB); - if (TC > 0u && TC < TinyTripCountThreshold) { + unsigned TC = SE->getSmallConstantTripCount(TheLoop, Latch); + if (TC > 0u && TC < TinyTripCountVectorThreshold) { DEBUG(dbgs() << "LV: Found a loop with a very small trip count. " << "This loop is not worth vectorizing.\n"); return false; } + // Check if we can vectorize the instructions and CFG in this loop. + if (!canVectorizeInstrs()) { + DEBUG(dbgs() << "LV: Can't vectorize the instructions or CFG\n"); + return false; + } + // Go over each instruction and look at memory deps. - if (!canVectorizeBlock(*BB)) { - DEBUG(dbgs() << "LV: Can't vectorize this loop header\n"); + if (!canVectorizeMemory()) { + DEBUG(dbgs() << "LV: Can't vectorize due to memory conflicts\n"); return false; } + // Collect all of the variables that remain uniform after vectorization. + collectLoopUniforms(); + DEBUG(dbgs() << "LV: We can vectorize this loop" << (PtrRtCheck.Need ? " (with a runtime bound check)" : "") <<"!\n"); @@ -1281,130 +2235,220 @@ bool LoopVectorizationLegality::canVectorize() { return true; } -bool LoopVectorizationLegality::canVectorizeBlock(BasicBlock &BB) { - // Scan the instructions in the block and look for hazards. - for (BasicBlock::iterator it = BB.begin(), e = BB.end(); it != e; ++it) { - Instruction *I = it; +bool LoopVectorizationLegality::canVectorizeInstrs() { + BasicBlock *PreHeader = TheLoop->getLoopPreheader(); + BasicBlock *Header = TheLoop->getHeader(); - PHINode *Phi = dyn_cast<PHINode>(I); - if (Phi) { - // This should not happen because the loop should be normalized. - if (Phi->getNumIncomingValues() != 2) { - DEBUG(dbgs() << "LV: Found an invalid PHI.\n"); - return false; - } - // We only look at integer phi nodes. - if (!Phi->getType()->isIntegerTy()) { - DEBUG(dbgs() << "LV: Found an non-int PHI.\n"); - return false; - } + // If we marked the scalar loop as "already vectorized" then no need + // to vectorize it again. + if (Header->getTerminator()->getMetadata(AlreadyVectorizedMDName)) { + DEBUG(dbgs() << "LV: This loop was vectorized before\n"); + return false; + } + + // For each block in the loop. + for (Loop::block_iterator bb = TheLoop->block_begin(), + be = TheLoop->block_end(); bb != be; ++bb) { - if (isInductionVariable(Phi)) { - if (Induction) { - DEBUG(dbgs() << "LV: Found too many inductions."<< *Phi <<"\n"); + // Scan the instructions in the block and look for hazards. + for (BasicBlock::iterator it = (*bb)->begin(), e = (*bb)->end(); it != e; + ++it) { + + if (PHINode *Phi = dyn_cast<PHINode>(it)) { + // This should not happen because the loop should be normalized. + if (Phi->getNumIncomingValues() != 2) { + DEBUG(dbgs() << "LV: Found an invalid PHI.\n"); return false; } - DEBUG(dbgs() << "LV: Found the induction PHI."<< *Phi <<"\n"); - Induction = Phi; - continue; - } - if (AddReductionVar(Phi, IntegerAdd)) { - DEBUG(dbgs() << "LV: Found an ADD reduction PHI."<< *Phi <<"\n"); - continue; - } - if (AddReductionVar(Phi, IntegerMult)) { - DEBUG(dbgs() << "LV: Found a MUL reduction PHI."<< *Phi <<"\n"); - continue; - } - if (AddReductionVar(Phi, IntegerOr)) { - DEBUG(dbgs() << "LV: Found an OR reduction PHI."<< *Phi <<"\n"); - continue; - } - if (AddReductionVar(Phi, IntegerAnd)) { - DEBUG(dbgs() << "LV: Found an AND reduction PHI."<< *Phi <<"\n"); - continue; - } - if (AddReductionVar(Phi, IntegerXor)) { - DEBUG(dbgs() << "LV: Found a XOR reduction PHI."<< *Phi <<"\n"); - continue; - } - DEBUG(dbgs() << "LV: Found an unidentified PHI."<< *Phi <<"\n"); - return false; - }// end of PHI handling + // Check that this PHI type is allowed. + if (!Phi->getType()->isIntegerTy() && + !Phi->getType()->isFloatingPointTy() && + !Phi->getType()->isPointerTy()) { + DEBUG(dbgs() << "LV: Found an non-int non-pointer PHI.\n"); + return false; + } - // We still don't handle functions. - CallInst *CI = dyn_cast<CallInst>(I); - if (CI) { - DEBUG(dbgs() << "LV: Found a call site.\n"); - return false; - } + // If this PHINode is not in the header block, then we know that we + // can convert it to select during if-conversion. No need to check if + // the PHIs in this block are induction or reduction variables. + if (*bb != Header) + continue; - // We do not re-vectorize vectors. - if (!VectorType::isValidElementType(I->getType()) && - !I->getType()->isVoidTy()) { - DEBUG(dbgs() << "LV: Found unvectorizable type." << "\n"); - return false; - } + // This is the value coming from the preheader. + Value *StartValue = Phi->getIncomingValueForBlock(PreHeader); + // Check if this is an induction variable. + InductionKind IK = isInductionVariable(Phi); + + if (IK_NoInduction != IK) { + // Int inductions are special because we only allow one IV. + if (IK == IK_IntInduction) { + if (Induction) { + DEBUG(dbgs() << "LV: Found too many inductions."<< *Phi <<"\n"); + return false; + } + Induction = Phi; + } + + DEBUG(dbgs() << "LV: Found an induction variable.\n"); + Inductions[Phi] = InductionInfo(StartValue, IK); + continue; + } - // Reduction instructions are allowed to have exit users. - // All other instructions must not have external users. - if (!AllowedExit.count(I)) - //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<Instruction>(*it); - // This user may be a reduction exit value. - BasicBlock *Parent = U->getParent(); - if (Parent != &BB) { - DEBUG(dbgs() << "LV: Found an outside user for : "<< *U << "\n"); + if (AddReductionVar(Phi, RK_IntegerAdd)) { + DEBUG(dbgs() << "LV: Found an ADD reduction PHI."<< *Phi <<"\n"); + continue; + } + if (AddReductionVar(Phi, RK_IntegerMult)) { + DEBUG(dbgs() << "LV: Found a MUL reduction PHI."<< *Phi <<"\n"); + continue; + } + if (AddReductionVar(Phi, RK_IntegerOr)) { + DEBUG(dbgs() << "LV: Found an OR reduction PHI."<< *Phi <<"\n"); + continue; + } + if (AddReductionVar(Phi, RK_IntegerAnd)) { + DEBUG(dbgs() << "LV: Found an AND reduction PHI."<< *Phi <<"\n"); + continue; + } + if (AddReductionVar(Phi, RK_IntegerXor)) { + DEBUG(dbgs() << "LV: Found a XOR reduction PHI."<< *Phi <<"\n"); + continue; + } + if (AddReductionVar(Phi, RK_FloatMult)) { + DEBUG(dbgs() << "LV: Found an FMult reduction PHI."<< *Phi <<"\n"); + continue; + } + if (AddReductionVar(Phi, RK_FloatAdd)) { + DEBUG(dbgs() << "LV: Found an FAdd reduction PHI."<< *Phi <<"\n"); + continue; + } + + DEBUG(dbgs() << "LV: Found an unidentified PHI."<< *Phi <<"\n"); + return false; + }// end of PHI handling + + // We still don't handle functions. However, we can ignore dbg intrinsic + // calls and we do handle certain intrinsic and libm functions. + CallInst *CI = dyn_cast<CallInst>(it); + if (CI && !getIntrinsicIDForCall(CI, TLI) && !isa<DbgInfoIntrinsic>(CI)) { + DEBUG(dbgs() << "LV: Found a call site.\n"); + return false; + } + + // Check that the instruction return type is vectorizable. + if (!VectorType::isValidElementType(it->getType()) && + !it->getType()->isVoidTy()) { + DEBUG(dbgs() << "LV: Found unvectorizable type." << "\n"); + return false; + } + + // Check that the stored type is vectorizable. + if (StoreInst *ST = dyn_cast<StoreInst>(it)) { + Type *T = ST->getValueOperand()->getType(); + if (!VectorType::isValidElementType(T)) return false; + } + + // Reduction instructions are allowed to have exit users. + // All other instructions must not have external users. + if (!AllowedExit.count(it)) + //Check that all of the users of the loop are inside the BB. + for (Value::use_iterator I = it->use_begin(), E = it->use_end(); + I != E; ++I) { + Instruction *U = cast<Instruction>(*I); + // This user may be a reduction exit value. + if (!TheLoop->contains(U)) { + DEBUG(dbgs() << "LV: Found an outside user for : "<< *U << "\n"); + return false; + } } - } - } // next instr. + } // next instr. + + } if (!Induction) { - DEBUG(dbgs() << "LV: Did not find an induction var.\n"); - return false; + DEBUG(dbgs() << "LV: Did not find one integer induction var.\n"); + assert(getInductionVars()->size() && "No induction variables"); } - // Don't vectorize if the memory dependencies do not allow vectorization. - if (!canVectorizeMemory(BB)) - return false; + return true; +} +void LoopVectorizationLegality::collectLoopUniforms() { // We now know that the loop is vectorizable! // Collect variables that will remain uniform after vectorization. std::vector<Value*> Worklist; + BasicBlock *Latch = TheLoop->getLoopLatch(); // Start with the conditional branch and walk up the block. - Worklist.push_back(BB.getTerminator()->getOperand(0)); + Worklist.push_back(Latch->getTerminator()->getOperand(0)); while (Worklist.size()) { Instruction *I = dyn_cast<Instruction>(Worklist.back()); Worklist.pop_back(); - // Look at instructions inside this block. - if (!I) continue; - if (I->getParent() != &BB) continue; + // Look at instructions inside this loop. // Stop when reaching PHI nodes. - if (isa<PHINode>(I)) { - assert(I == Induction && "Found a uniform PHI that is not the induction"); - break; - } + // TODO: we need to follow values all over the loop, not only in this block. + if (!I || !TheLoop->contains(I) || isa<PHINode>(I)) + continue; // This is a known uniform. Uniforms.insert(I); // Insert all operands. - for (int i=0, Op = I->getNumOperands(); i < Op; ++i) { + for (int i = 0, Op = I->getNumOperands(); i < Op; ++i) { Worklist.push_back(I->getOperand(i)); } } +} - return true; +AliasAnalysis::Location +LoopVectorizationLegality::getLoadStoreLocation(Instruction *Inst) { + if (StoreInst *Store = dyn_cast<StoreInst>(Inst)) + return AA->getLocation(Store); + else if (LoadInst *Load = dyn_cast<LoadInst>(Inst)) + return AA->getLocation(Load); + + llvm_unreachable("Should be either load or store instruction"); } -bool LoopVectorizationLegality::canVectorizeMemory(BasicBlock &BB) { +bool +LoopVectorizationLegality::hasPossibleGlobalWriteReorder( + Value *Object, + Instruction *Inst, + AliasMultiMap& WriteObjects, + unsigned MaxByteWidth) { + + AliasAnalysis::Location ThisLoc = getLoadStoreLocation(Inst); + + std::vector<Instruction*>::iterator + it = WriteObjects[Object].begin(), + end = WriteObjects[Object].end(); + + for (; it != end; ++it) { + Instruction* I = *it; + if (I == Inst) + continue; + + AliasAnalysis::Location ThatLoc = getLoadStoreLocation(I); + if (AA->alias(ThisLoc.getWithNewSize(MaxByteWidth), + ThatLoc.getWithNewSize(MaxByteWidth))) + return true; + } + return false; +} + +bool LoopVectorizationLegality::canVectorizeMemory() { + + if (TheLoop->isAnnotatedParallel()) { + DEBUG(dbgs() + << "LV: A loop annotated parallel, ignore memory dependency " + << "checks.\n"); + return true; + } + typedef SmallVector<Value*, 16> ValueVector; typedef SmallPtrSet<Value*, 16> ValueSet; // Holds the Load and Store *instructions*. @@ -1413,35 +2457,40 @@ bool LoopVectorizationLegality::canVectorizeMemory(BasicBlock &BB) { PtrRtCheck.Pointers.clear(); PtrRtCheck.Need = false; - // Scan the BB and collect legal loads and stores. - for (BasicBlock::iterator it = BB.begin(), e = BB.end(); it != e; ++it) { - Instruction *I = it; - - // If this is a load, save it. If this instruction can read from memory - // but is not a load, then we quit. Notice that we don't handle function - // calls that read or write. - if (I->mayReadFromMemory()) { - LoadInst *Ld = dyn_cast<LoadInst>(I); - if (!Ld) return false; - if (!Ld->isSimple()) { - DEBUG(dbgs() << "LV: Found a non-simple load.\n"); - return false; + // For each block. + for (Loop::block_iterator bb = TheLoop->block_begin(), + be = TheLoop->block_end(); bb != be; ++bb) { + + // Scan the BB and collect legal loads and stores. + for (BasicBlock::iterator it = (*bb)->begin(), e = (*bb)->end(); it != e; + ++it) { + + // If this is a load, save it. If this instruction can read from memory + // but is not a load, then we quit. Notice that we don't handle function + // calls that read or write. + if (it->mayReadFromMemory()) { + LoadInst *Ld = dyn_cast<LoadInst>(it); + if (!Ld) return false; + if (!Ld->isSimple()) { + DEBUG(dbgs() << "LV: Found a non-simple load.\n"); + return false; + } + Loads.push_back(Ld); + continue; } - Loads.push_back(Ld); - continue; - } - // Save store instructions. Abort if other instructions write to memory. - if (I->mayWriteToMemory()) { - StoreInst *St = dyn_cast<StoreInst>(I); - if (!St) return false; - if (!St->isSimple()) { - DEBUG(dbgs() << "LV: Found a non-simple store.\n"); - return false; + // Save 'store' instructions. Abort if other instructions write to memory. + if (it->mayWriteToMemory()) { + StoreInst *St = dyn_cast<StoreInst>(it); + if (!St) return false; + if (!St->isSimple()) { + DEBUG(dbgs() << "LV: Found a non-simple store.\n"); + return false; + } + Stores.push_back(St); } - Stores.push_back(St); - } - } // next instr. + } // next instr. + } // next block. // Now we have two lists that hold the loads and the stores. // Next, we find the pointers that they use. @@ -1449,13 +2498,14 @@ bool LoopVectorizationLegality::canVectorizeMemory(BasicBlock &BB) { // Check if we see any stores. If there are no stores, then we don't // care if the pointers are *restrict*. if (!Stores.size()) { - DEBUG(dbgs() << "LV: Found a read-only loop!\n"); - return true; + DEBUG(dbgs() << "LV: Found a read-only loop!\n"); + return true; } - // Holds the read and read-write *pointers* that we find. - ValueVector Reads; - ValueVector ReadWrites; + // Holds the read and read-write *pointers* that we find. These maps hold + // unique values for pointers (so no need for multi-map). + AliasMap Reads; + AliasMap ReadWrites; // Holds the analyzed pointers. We don't want to call GetUnderlyingObjects // multiple times on the same object. If the ptr is accessed twice, once @@ -1466,8 +2516,7 @@ bool LoopVectorizationLegality::canVectorizeMemory(BasicBlock &BB) { ValueVector::iterator I, IE; for (I = Stores.begin(), IE = Stores.end(); I != IE; ++I) { - StoreInst *ST = dyn_cast<StoreInst>(*I); - assert(ST && "Bad StoreInst"); + StoreInst *ST = cast<StoreInst>(*I); Value* Ptr = ST->getPointerOperand(); if (isUniform(Ptr)) { @@ -1478,12 +2527,11 @@ bool LoopVectorizationLegality::canVectorizeMemory(BasicBlock &BB) { // If we did *not* see this pointer before, insert it to // the read-write list. At this phase it is only a 'write' list. if (Seen.insert(Ptr)) - ReadWrites.push_back(Ptr); + ReadWrites.insert(std::make_pair(Ptr, ST)); } for (I = Loads.begin(), IE = Loads.end(); I != IE; ++I) { - LoadInst *LD = dyn_cast<LoadInst>(*I); - assert(LD && "Bad LoadInst"); + LoadInst *LD = cast<LoadInst>(*I); Value* Ptr = LD->getPointerOperand(); // If we did *not* see this pointer before, insert it to the // read list. If we *did* see it before, then it is already in @@ -1493,8 +2541,8 @@ bool LoopVectorizationLegality::canVectorizeMemory(BasicBlock &BB) { // If the address of i is unknown (for example A[B[i]]) then we may // read a few words, modify, and write a few words, and some of the // words may be written to the same address. - if (Seen.insert(Ptr) || !isConsecutiveGep(Ptr)) - Reads.push_back(Ptr); + if (Seen.insert(Ptr) || 0 == isConsecutivePtr(Ptr)) + Reads.insert(std::make_pair(Ptr, LD)); } // If we write (or read-write) to a single destination and there are no @@ -1506,84 +2554,156 @@ bool LoopVectorizationLegality::canVectorizeMemory(BasicBlock &BB) { // Find pointers with computable bounds. We are going to use this information // to place a runtime bound check. - bool RT = true; - for (I = ReadWrites.begin(), IE = ReadWrites.end(); I != IE; ++I) - if (hasComputableBounds(*I)) { - PtrRtCheck.Pointers.push_back(*I); - DEBUG(dbgs() << "LV: Found a runtime check ptr:" << **I <<"\n"); + bool CanDoRT = true; + AliasMap::iterator MI, ME; + for (MI = ReadWrites.begin(), ME = ReadWrites.end(); MI != ME; ++MI) { + Value *V = (*MI).first; + if (hasComputableBounds(V)) { + PtrRtCheck.insert(SE, TheLoop, V); + DEBUG(dbgs() << "LV: Found a runtime check ptr:" << *V <<"\n"); } else { - RT = false; + CanDoRT = false; break; } - for (I = Reads.begin(), IE = Reads.end(); I != IE; ++I) - if (hasComputableBounds(*I)) { - PtrRtCheck.Pointers.push_back(*I); - DEBUG(dbgs() << "LV: Found a runtime check ptr:" << **I <<"\n"); + } + for (MI = Reads.begin(), ME = Reads.end(); MI != ME; ++MI) { + Value *V = (*MI).first; + if (hasComputableBounds(V)) { + PtrRtCheck.insert(SE, TheLoop, V); + DEBUG(dbgs() << "LV: Found a runtime check ptr:" << *V <<"\n"); } else { - RT = false; + CanDoRT = false; break; } + } // Check that we did not collect too many pointers or found a // unsizeable pointer. - if (!RT || PtrRtCheck.Pointers.size() > RuntimeMemoryCheckThreshold) { - PtrRtCheck.Pointers.clear(); - RT = false; + if (!CanDoRT || PtrRtCheck.Pointers.size() > RuntimeMemoryCheckThreshold) { + PtrRtCheck.reset(); + CanDoRT = false; } - PtrRtCheck.Need = RT; - - if (RT) { + if (CanDoRT) { DEBUG(dbgs() << "LV: We can perform a memory runtime check if needed.\n"); } + bool NeedRTCheck = false; + + // Biggest vectorized access possible, vector width * unroll factor. + // TODO: We're being very pessimistic here, find a way to know the + // real access width before getting here. + unsigned MaxByteWidth = (TTI->getRegisterBitWidth(true) / 8) * + TTI->getMaximumUnrollFactor(); // Now that the pointers are in two lists (Reads and ReadWrites), we // can check that there are no conflicts between each of the writes and // between the writes to the reads. - ValueSet WriteObjects; + // Note that WriteObjects duplicates the stores (indexed now by underlying + // objects) to avoid pointing to elements inside ReadWrites. + // TODO: Maybe create a new type where they can interact without duplication. + AliasMultiMap WriteObjects; ValueVector TempObjects; // Check that the read-writes do not conflict with other read-write // pointers. - for (I = ReadWrites.begin(), IE = ReadWrites.end(); I != IE; ++I) { - GetUnderlyingObjects(*I, TempObjects, DL); - for (ValueVector::iterator it=TempObjects.begin(), e=TempObjects.end(); - it != e; ++it) { - if (!isIdentifiedObject(*it)) { - DEBUG(dbgs() << "LV: Found an unidentified write ptr:"<< **it <<"\n"); - return RT; + bool AllWritesIdentified = true; + for (MI = ReadWrites.begin(), ME = ReadWrites.end(); MI != ME; ++MI) { + Value *Val = (*MI).first; + Instruction *Inst = (*MI).second; + + GetUnderlyingObjects(Val, TempObjects, DL); + for (ValueVector::iterator UI=TempObjects.begin(), UE=TempObjects.end(); + UI != UE; ++UI) { + if (!isIdentifiedObject(*UI)) { + DEBUG(dbgs() << "LV: Found an unidentified write ptr:"<< **UI <<"\n"); + NeedRTCheck = true; + AllWritesIdentified = false; } - if (!WriteObjects.insert(*it)) { + + // Never seen it before, can't alias. + if (WriteObjects[*UI].empty()) { + DEBUG(dbgs() << "LV: Adding Underlying value:" << **UI <<"\n"); + WriteObjects[*UI].push_back(Inst); + continue; + } + // Direct alias found. + if (!AA || dyn_cast<GlobalValue>(*UI) == NULL) { + DEBUG(dbgs() << "LV: Found a possible write-write reorder:" + << **UI <<"\n"); + return false; + } + DEBUG(dbgs() << "LV: Found a conflicting global value:" + << **UI <<"\n"); + DEBUG(dbgs() << "LV: While examining store:" << *Inst <<"\n"); + DEBUG(dbgs() << "LV: On value:" << *Val <<"\n"); + + // If global alias, make sure they do alias. + if (hasPossibleGlobalWriteReorder(*UI, + Inst, + WriteObjects, + MaxByteWidth)) { DEBUG(dbgs() << "LV: Found a possible write-write reorder:" - << **it <<"\n"); - return RT; + << *UI <<"\n"); + return false; } + + // Didn't alias, insert into map for further reference. + WriteObjects[*UI].push_back(Inst); } TempObjects.clear(); } /// Check that the reads don't conflict with the read-writes. - for (I = Reads.begin(), IE = Reads.end(); I != IE; ++I) { - GetUnderlyingObjects(*I, TempObjects, DL); - for (ValueVector::iterator it=TempObjects.begin(), e=TempObjects.end(); - it != e; ++it) { - if (!isIdentifiedObject(*it)) { - DEBUG(dbgs() << "LV: Found an unidentified read ptr:"<< **it <<"\n"); - return RT; + for (MI = Reads.begin(), ME = Reads.end(); MI != ME; ++MI) { + Value *Val = (*MI).first; + GetUnderlyingObjects(Val, TempObjects, DL); + for (ValueVector::iterator UI=TempObjects.begin(), UE=TempObjects.end(); + UI != UE; ++UI) { + // If all of the writes are identified then we don't care if the read + // pointer is identified or not. + if (!AllWritesIdentified && !isIdentifiedObject(*UI)) { + DEBUG(dbgs() << "LV: Found an unidentified read ptr:"<< **UI <<"\n"); + NeedRTCheck = true; } - if (WriteObjects.count(*it)) { - DEBUG(dbgs() << "LV: Found a possible read/write reorder:" - << **it <<"\n"); - return RT; + + // Never seen it before, can't alias. + if (WriteObjects[*UI].empty()) + continue; + // Direct alias found. + if (!AA || dyn_cast<GlobalValue>(*UI) == NULL) { + DEBUG(dbgs() << "LV: Found a possible write-write reorder:" + << **UI <<"\n"); + return false; + } + DEBUG(dbgs() << "LV: Found a global value: " + << **UI <<"\n"); + Instruction *Inst = (*MI).second; + DEBUG(dbgs() << "LV: While examining load:" << *Inst <<"\n"); + DEBUG(dbgs() << "LV: On value:" << *Val <<"\n"); + + // If global alias, make sure they do alias. + if (hasPossibleGlobalWriteReorder(*UI, + Inst, + WriteObjects, + MaxByteWidth)) { + DEBUG(dbgs() << "LV: Found a possible read-write reorder:" + << *UI <<"\n"); + return false; } } TempObjects.clear(); } - // It is safe to vectorize and we don't need any runtime checks. - DEBUG(dbgs() << "LV: We don't need a runtime memory check.\n"); - PtrRtCheck.Pointers.clear(); - PtrRtCheck.Need = false; + PtrRtCheck.Need = NeedRTCheck; + if (NeedRTCheck && !CanDoRT) { + DEBUG(dbgs() << "LV: We can't vectorize because we can't find " << + "the array bounds.\n"); + PtrRtCheck.reset(); + return false; + } + + DEBUG(dbgs() << "LV: We "<< (NeedRTCheck ? "" : "don't") << + " need a runtime memory check.\n"); return true; } @@ -1592,38 +2712,43 @@ bool LoopVectorizationLegality::AddReductionVar(PHINode *Phi, if (Phi->getNumIncomingValues() != 2) return false; - // Find the possible incoming reduction variable. - BasicBlock *BB = Phi->getParent(); - int SelfEdgeIdx = Phi->getBasicBlockIndex(BB); - int InEdgeBlockIdx = (SelfEdgeIdx ? 0 : 1); // The other entry. - Value *RdxStart = Phi->getIncomingValue(InEdgeBlockIdx); + // Reduction variables are only found in the loop header block. + if (Phi->getParent() != TheLoop->getHeader()) + return false; + + // Obtain the reduction start value from the value that comes from the loop + // preheader. + Value *RdxStart = Phi->getIncomingValueForBlock(TheLoop->getLoopPreheader()); // ExitInstruction is the single value which is used outside the loop. // We only allow for a single reduction value to be used outside the loop. // This includes users of the reduction, variables (which form a cycle // which ends in the phi node). Instruction *ExitInstruction = 0; + // Indicates that we found a binary operation in our scan. + bool FoundBinOp = false; // Iter is our iterator. We start with the PHI node and scan for all of the - // users of this instruction. All users must be instructions which can be + // users of this instruction. All users must be instructions that can be // used as reduction variables (such as ADD). We may have a single - // out-of-block user. They cycle must end with the original PHI. - // Also, we can't have multiple block-local users. + // out-of-block user. The cycle must end with the original PHI. Instruction *Iter = Phi; while (true) { - // Any reduction instr must be of one of the allowed kinds. - if (!isReductionInstr(Iter, Kind)) + // If the instruction has no users then this is a broken + // chain and can't be a reduction variable. + if (Iter->use_empty()) return false; - // Did we found a user inside this block ? + // Did we find a user inside this loop already ? bool FoundInBlockUser = false; - // Did we reach the initial PHI node ? + // Did we reach the initial PHI node already ? bool FoundStartPHI = false; - // If the instruction has no users then this is a broken - // chain and can't be a reduction variable. - if (Iter->use_empty()) - return false; + // Is this a bin op ? + FoundBinOp |= !isa<PHINode>(Iter); + + // Remember the current instruction. + Instruction *OldIter = Iter; // For each of the *users* of iter. for (Value::use_iterator it = Iter->use_begin(), e = Iter->use_end(); @@ -1634,75 +2759,171 @@ bool LoopVectorizationLegality::AddReductionVar(PHINode *Phi, FoundStartPHI = true; continue; } + // Check if we found the exit user. BasicBlock *Parent = U->getParent(); - if (Parent != BB) { - // We must have a single exit instruction. + if (!TheLoop->contains(Parent)) { + // Exit if you find multiple outside users. if (ExitInstruction != 0) return false; ExitInstruction = Iter; } + + // We allow in-loop PHINodes which are not the original reduction PHI + // node. If this PHI is the only user of Iter (happens in IF w/ no ELSE + // structure) then don't skip this PHI. + if (isa<PHINode>(Iter) && isa<PHINode>(U) && + U->getParent() != TheLoop->getHeader() && + TheLoop->contains(U) && + Iter->hasNUsesOrMore(2)) + continue; + // We can't have multiple inside users. if (FoundInBlockUser) return false; FoundInBlockUser = true; + + // Any reduction instr must be of one of the allowed kinds. + if (!isReductionInstr(U, Kind)) + return false; + + // Reductions of instructions such as Div, and Sub is only + // possible if the LHS is the reduction variable. + if (!U->isCommutative() && !isa<PHINode>(U) && U->getOperand(0) != Iter) + return false; + Iter = U; } + // If all uses were skipped this can't be a reduction variable. + if (Iter == OldIter) + return false; + // We found a reduction var if we have reached the original // phi node and we only have a single instruction with out-of-loop // users. - if (FoundStartPHI && ExitInstruction) { - // This instruction is allowed to have out-of-loop users. - AllowedExit.insert(ExitInstruction); - - // Save the description of this reduction variable. - ReductionDescriptor RD(RdxStart, ExitInstruction, Kind); - Reductions[Phi] = RD; - return true; - } + if (FoundStartPHI) { + // This instruction is allowed to have out-of-loop users. + AllowedExit.insert(ExitInstruction); + + // Save the description of this reduction variable. + ReductionDescriptor RD(RdxStart, ExitInstruction, Kind); + Reductions[Phi] = RD; + // We've ended the cycle. This is a reduction variable if we have an + // outside user and it has a binary op. + return FoundBinOp && ExitInstruction; + } } } bool LoopVectorizationLegality::isReductionInstr(Instruction *I, ReductionKind Kind) { - switch (I->getOpcode()) { - default: - return false; - case Instruction::PHI: - // possibly. - return true; - case Instruction::Add: - case Instruction::Sub: - return Kind == IntegerAdd; - case Instruction::Mul: - case Instruction::UDiv: - case Instruction::SDiv: - return Kind == IntegerMult; - case Instruction::And: - return Kind == IntegerAnd; - case Instruction::Or: - return Kind == IntegerOr; - case Instruction::Xor: - return Kind == IntegerXor; - } + bool FP = I->getType()->isFloatingPointTy(); + bool FastMath = (FP && I->isCommutative() && I->isAssociative()); + + switch (I->getOpcode()) { + default: + return false; + case Instruction::PHI: + if (FP && (Kind != RK_FloatMult && Kind != RK_FloatAdd)) + return false; + // possibly. + return true; + case Instruction::Sub: + case Instruction::Add: + return Kind == RK_IntegerAdd; + case Instruction::SDiv: + case Instruction::UDiv: + case Instruction::Mul: + return Kind == RK_IntegerMult; + case Instruction::And: + return Kind == RK_IntegerAnd; + case Instruction::Or: + return Kind == RK_IntegerOr; + case Instruction::Xor: + return Kind == RK_IntegerXor; + case Instruction::FMul: + return Kind == RK_FloatMult && FastMath; + case Instruction::FAdd: + return Kind == RK_FloatAdd && FastMath; + } } -bool LoopVectorizationLegality::isInductionVariable(PHINode *Phi) { - // Check that the PHI is consecutive and starts at zero. +LoopVectorizationLegality::InductionKind +LoopVectorizationLegality::isInductionVariable(PHINode *Phi) { + Type *PhiTy = Phi->getType(); + // We only handle integer and pointer inductions variables. + if (!PhiTy->isIntegerTy() && !PhiTy->isPointerTy()) + return IK_NoInduction; + + // Check that the PHI is consecutive. const SCEV *PhiScev = SE->getSCEV(Phi); const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PhiScev); if (!AR) { DEBUG(dbgs() << "LV: PHI is not a poly recurrence.\n"); - return false; + return IK_NoInduction; } const SCEV *Step = AR->getStepRecurrence(*SE); - if (!Step->isOne()) { - DEBUG(dbgs() << "LV: PHI stride does not equal one.\n"); + // Integer inductions need to have a stride of one. + if (PhiTy->isIntegerTy()) { + if (Step->isOne()) + return IK_IntInduction; + if (Step->isAllOnesValue()) + return IK_ReverseIntInduction; + return IK_NoInduction; + } + + // Calculate the pointer stride and check if it is consecutive. + const SCEVConstant *C = dyn_cast<SCEVConstant>(Step); + if (!C) + return IK_NoInduction; + + assert(PhiTy->isPointerTy() && "The PHI must be a pointer"); + uint64_t Size = DL->getTypeAllocSize(PhiTy->getPointerElementType()); + if (C->getValue()->equalsInt(Size)) + return IK_PtrInduction; + else if (C->getValue()->equalsInt(0 - Size)) + return IK_ReversePtrInduction; + + return IK_NoInduction; +} + +bool LoopVectorizationLegality::isInductionVariable(const Value *V) { + Value *In0 = const_cast<Value*>(V); + PHINode *PN = dyn_cast_or_null<PHINode>(In0); + if (!PN) return false; + + return Inductions.count(PN); +} + +bool LoopVectorizationLegality::blockNeedsPredication(BasicBlock *BB) { + assert(TheLoop->contains(BB) && "Unknown block used"); + + // Blocks that do not dominate the latch need predication. + BasicBlock* Latch = TheLoop->getLoopLatch(); + return !DT->dominates(BB, Latch); +} + +bool LoopVectorizationLegality::blockCanBePredicated(BasicBlock *BB) { + for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) { + // We don't predicate loads/stores at the moment. + if (it->mayReadFromMemory() || it->mayWriteToMemory() || it->mayThrow()) + return false; + + // The instructions below can trap. + switch (it->getOpcode()) { + default: continue; + case Instruction::UDiv: + case Instruction::SDiv: + case Instruction::URem: + case Instruction::SRem: + return false; + } } + return true; } @@ -1715,11 +2936,64 @@ bool LoopVectorizationLegality::hasComputableBounds(Value *Ptr) { return AR->isAffine(); } -unsigned -LoopVectorizationCostModel::findBestVectorizationFactor(unsigned VF) { - if (!VTTI) { - DEBUG(dbgs() << "LV: No vector target information. Not vectorizing. \n"); - return 1; +LoopVectorizationCostModel::VectorizationFactor +LoopVectorizationCostModel::selectVectorizationFactor(bool OptForSize, + unsigned UserVF) { + // Width 1 means no vectorize + VectorizationFactor Factor = { 1U, 0U }; + if (OptForSize && Legal->getRuntimePointerCheck()->Need) { + DEBUG(dbgs() << "LV: Aborting. Runtime ptr check is required in Os.\n"); + return Factor; + } + + // Find the trip count. + unsigned TC = SE->getSmallConstantTripCount(TheLoop, TheLoop->getLoopLatch()); + DEBUG(dbgs() << "LV: Found trip count:"<<TC<<"\n"); + + unsigned WidestType = getWidestType(); + unsigned WidestRegister = TTI.getRegisterBitWidth(true); + unsigned MaxVectorSize = WidestRegister / WidestType; + DEBUG(dbgs() << "LV: The Widest type: " << WidestType << " bits.\n"); + DEBUG(dbgs() << "LV: The Widest register is:" << WidestRegister << "bits.\n"); + + if (MaxVectorSize == 0) { + DEBUG(dbgs() << "LV: The target has no vector registers.\n"); + MaxVectorSize = 1; + } + + assert(MaxVectorSize <= 32 && "Did not expect to pack so many elements" + " into one vector!"); + + unsigned VF = MaxVectorSize; + + // If we optimize the program for size, avoid creating the tail loop. + if (OptForSize) { + // If we are unable to calculate the trip count then don't try to vectorize. + if (TC < 2) { + DEBUG(dbgs() << "LV: Aborting. A tail loop is required in Os.\n"); + return Factor; + } + + // Find the maximum SIMD width that can fit within the trip count. + VF = TC % MaxVectorSize; + + if (VF == 0) + VF = MaxVectorSize; + + // If the trip count that we found modulo the vectorization factor is not + // zero then we require a tail. + if (VF < 2) { + DEBUG(dbgs() << "LV: Aborting. A tail loop is required in Os.\n"); + return Factor; + } + } + + if (UserVF != 0) { + assert(isPowerOf2_32(UserVF) && "VF needs to be a power of two"); + DEBUG(dbgs() << "LV: Using user VF "<<UserVF<<".\n"); + + Factor.Width = UserVF; + return Factor; } float Cost = expectedCost(1); @@ -1739,23 +3013,278 @@ LoopVectorizationCostModel::findBestVectorizationFactor(unsigned VF) { } DEBUG(dbgs() << "LV: Selecting VF = : "<< Width << ".\n"); - return Width; + Factor.Width = Width; + Factor.Cost = Width * Cost; + return Factor; } -unsigned LoopVectorizationCostModel::expectedCost(unsigned VF) { - // We can only estimate the cost of single basic block loops. - assert(1 == TheLoop->getNumBlocks() && "Too many blocks in loop"); +unsigned LoopVectorizationCostModel::getWidestType() { + unsigned MaxWidth = 8; + + // For each block. + for (Loop::block_iterator bb = TheLoop->block_begin(), + be = TheLoop->block_end(); bb != be; ++bb) { + BasicBlock *BB = *bb; + + // For each instruction in the loop. + for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) { + Type *T = it->getType(); - BasicBlock *BB = TheLoop->getHeader(); + // Only examine Loads, Stores and PHINodes. + if (!isa<LoadInst>(it) && !isa<StoreInst>(it) && !isa<PHINode>(it)) + continue; + + // Examine PHI nodes that are reduction variables. + if (PHINode *PN = dyn_cast<PHINode>(it)) + if (!Legal->getReductionVars()->count(PN)) + continue; + + // Examine the stored values. + if (StoreInst *ST = dyn_cast<StoreInst>(it)) + T = ST->getValueOperand()->getType(); + + // Ignore loaded pointer types and stored pointer types that are not + // consecutive. However, we do want to take consecutive stores/loads of + // pointer vectors into account. + if (T->isPointerTy() && !isConsecutiveLoadOrStore(it)) + continue; + + MaxWidth = std::max(MaxWidth, + (unsigned)DL->getTypeSizeInBits(T->getScalarType())); + } + } + + return MaxWidth; +} + +unsigned +LoopVectorizationCostModel::selectUnrollFactor(bool OptForSize, + unsigned UserUF, + unsigned VF, + unsigned LoopCost) { + + // -- The unroll heuristics -- + // We unroll the loop in order to expose ILP and reduce the loop overhead. + // There are many micro-architectural considerations that we can't predict + // at this level. For example frontend pressure (on decode or fetch) due to + // code size, or the number and capabilities of the execution ports. + // + // We use the following heuristics to select the unroll factor: + // 1. If the code has reductions the we unroll in order to break the cross + // iteration dependency. + // 2. If the loop is really small then we unroll in order to reduce the loop + // overhead. + // 3. We don't unroll if we think that we will spill registers to memory due + // to the increased register pressure. + + // Use the user preference, unless 'auto' is selected. + if (UserUF != 0) + return UserUF; + + // When we optimize for size we don't unroll. + if (OptForSize) + return 1; + + // Do not unroll loops with a relatively small trip count. + unsigned TC = SE->getSmallConstantTripCount(TheLoop, + TheLoop->getLoopLatch()); + if (TC > 1 && TC < TinyTripCountUnrollThreshold) + return 1; + + unsigned TargetVectorRegisters = TTI.getNumberOfRegisters(true); + DEBUG(dbgs() << "LV: The target has " << TargetVectorRegisters << + " vector registers\n"); + + LoopVectorizationCostModel::RegisterUsage R = calculateRegisterUsage(); + // We divide by these constants so assume that we have at least one + // instruction that uses at least one register. + R.MaxLocalUsers = std::max(R.MaxLocalUsers, 1U); + R.NumInstructions = std::max(R.NumInstructions, 1U); + + // We calculate the unroll factor using the following formula. + // Subtract the number of loop invariants from the number of available + // registers. These registers are used by all of the unrolled instances. + // Next, divide the remaining registers by the number of registers that is + // required by the loop, in order to estimate how many parallel instances + // fit without causing spills. + unsigned UF = (TargetVectorRegisters - R.LoopInvariantRegs) / R.MaxLocalUsers; + + // Clamp the unroll factor ranges to reasonable factors. + unsigned MaxUnrollSize = TTI.getMaximumUnrollFactor(); + + // If we did not calculate the cost for VF (because the user selected the VF) + // then we calculate the cost of VF here. + if (LoopCost == 0) + LoopCost = expectedCost(VF); + + // Clamp the calculated UF to be between the 1 and the max unroll factor + // that the target allows. + if (UF > MaxUnrollSize) + UF = MaxUnrollSize; + else if (UF < 1) + UF = 1; + + if (Legal->getReductionVars()->size()) { + DEBUG(dbgs() << "LV: Unrolling because of reductions. \n"); + return UF; + } + + // We want to unroll tiny loops in order to reduce the loop overhead. + // We assume that the cost overhead is 1 and we use the cost model + // to estimate the cost of the loop and unroll until the cost of the + // loop overhead is about 5% of the cost of the loop. + DEBUG(dbgs() << "LV: Loop cost is "<< LoopCost <<" \n"); + if (LoopCost < 20) { + DEBUG(dbgs() << "LV: Unrolling to reduce branch cost. \n"); + unsigned NewUF = 20/LoopCost + 1; + return std::min(NewUF, UF); + } + + DEBUG(dbgs() << "LV: Not Unrolling. \n"); + return 1; +} + +LoopVectorizationCostModel::RegisterUsage +LoopVectorizationCostModel::calculateRegisterUsage() { + // This function calculates the register usage by measuring the highest number + // of values that are alive at a single location. Obviously, this is a very + // rough estimation. We scan the loop in a topological order in order and + // assign a number to each instruction. We use RPO to ensure that defs are + // met before their users. We assume that each instruction that has in-loop + // users starts an interval. We record every time that an in-loop value is + // used, so we have a list of the first and last occurrences of each + // instruction. Next, we transpose this data structure into a multi map that + // holds the list of intervals that *end* at a specific location. This multi + // map allows us to perform a linear search. We scan the instructions linearly + // and record each time that a new interval starts, by placing it in a set. + // If we find this value in the multi-map then we remove it from the set. + // The max register usage is the maximum size of the set. + // We also search for instructions that are defined outside the loop, but are + // used inside the loop. We need this number separately from the max-interval + // usage number because when we unroll, loop-invariant values do not take + // more register. + LoopBlocksDFS DFS(TheLoop); + DFS.perform(LI); + + RegisterUsage R; + R.NumInstructions = 0; + + // Each 'key' in the map opens a new interval. The values + // of the map are the index of the 'last seen' usage of the + // instruction that is the key. + typedef DenseMap<Instruction*, unsigned> IntervalMap; + // Maps instruction to its index. + DenseMap<unsigned, Instruction*> IdxToInstr; + // Marks the end of each interval. + IntervalMap EndPoint; + // Saves the list of instruction indices that are used in the loop. + SmallSet<Instruction*, 8> Ends; + // Saves the list of values that are used in the loop but are + // defined outside the loop, such as arguments and constants. + SmallPtrSet<Value*, 8> LoopInvariants; + + unsigned Index = 0; + for (LoopBlocksDFS::RPOIterator bb = DFS.beginRPO(), + be = DFS.endRPO(); bb != be; ++bb) { + R.NumInstructions += (*bb)->size(); + for (BasicBlock::iterator it = (*bb)->begin(), e = (*bb)->end(); it != e; + ++it) { + Instruction *I = it; + IdxToInstr[Index++] = I; + + // Save the end location of each USE. + for (unsigned i = 0; i < I->getNumOperands(); ++i) { + Value *U = I->getOperand(i); + Instruction *Instr = dyn_cast<Instruction>(U); + + // Ignore non-instruction values such as arguments, constants, etc. + if (!Instr) continue; + + // If this instruction is outside the loop then record it and continue. + if (!TheLoop->contains(Instr)) { + LoopInvariants.insert(Instr); + continue; + } + + // Overwrite previous end points. + EndPoint[Instr] = Index; + Ends.insert(Instr); + } + } + } + + // Saves the list of intervals that end with the index in 'key'. + typedef SmallVector<Instruction*, 2> InstrList; + DenseMap<unsigned, InstrList> TransposeEnds; + + // Transpose the EndPoints to a list of values that end at each index. + for (IntervalMap::iterator it = EndPoint.begin(), e = EndPoint.end(); + it != e; ++it) + TransposeEnds[it->second].push_back(it->first); + + SmallSet<Instruction*, 8> OpenIntervals; + unsigned MaxUsage = 0; + + + DEBUG(dbgs() << "LV(REG): Calculating max register usage:\n"); + for (unsigned int i = 0; i < Index; ++i) { + Instruction *I = IdxToInstr[i]; + // Ignore instructions that are never used within the loop. + if (!Ends.count(I)) continue; + + // Remove all of the instructions that end at this location. + InstrList &List = TransposeEnds[i]; + for (unsigned int j=0, e = List.size(); j < e; ++j) + OpenIntervals.erase(List[j]); + + // Count the number of live interals. + MaxUsage = std::max(MaxUsage, OpenIntervals.size()); + + DEBUG(dbgs() << "LV(REG): At #" << i << " Interval # " << + OpenIntervals.size() <<"\n"); + + // Add the current instruction to the list of open intervals. + OpenIntervals.insert(I); + } + + unsigned Invariant = LoopInvariants.size(); + DEBUG(dbgs() << "LV(REG): Found max usage: " << MaxUsage << " \n"); + DEBUG(dbgs() << "LV(REG): Found invariant usage: " << Invariant << " \n"); + DEBUG(dbgs() << "LV(REG): LoopSize: " << R.NumInstructions << " \n"); + + R.LoopInvariantRegs = Invariant; + R.MaxLocalUsers = MaxUsage; + return R; +} + +unsigned LoopVectorizationCostModel::expectedCost(unsigned VF) { unsigned Cost = 0; - // For each instruction in the old loop. - for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) { - Instruction *Inst = it; - unsigned C = getInstructionCost(Inst, VF); - Cost += C; - DEBUG(dbgs() << "LV: Found an estimated cost of "<< C <<" for VF "<< VF << - " For instruction: "<< *Inst << "\n"); + // For each block. + for (Loop::block_iterator bb = TheLoop->block_begin(), + be = TheLoop->block_end(); bb != be; ++bb) { + unsigned BlockCost = 0; + BasicBlock *BB = *bb; + + // For each instruction in the old loop. + for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) { + // Skip dbg intrinsics. + if (isa<DbgInfoIntrinsic>(it)) + continue; + + unsigned C = getInstructionCost(it, VF); + Cost += C; + DEBUG(dbgs() << "LV: Found an estimated cost of "<< C <<" for VF " << + VF << " For instruction: "<< *it << "\n"); + } + + // We assume that if-converted blocks have a 50% chance of being executed. + // When the code is scalar then some of the blocks are avoided due to CF. + // When the code is vectorized we execute all code paths. + if (Legal->blockNeedsPredication(*bb) && VF == 1) + BlockCost /= 2; + + Cost += BlockCost; } return Cost; @@ -1763,8 +3292,6 @@ unsigned LoopVectorizationCostModel::expectedCost(unsigned VF) { unsigned LoopVectorizationCostModel::getInstructionCost(Instruction *I, unsigned VF) { - assert(VTTI && "Invalid vector target transformation info"); - // If we know that this instruction will remain uniform, check the cost of // the scalar version. if (Legal->isUniformAfterVectorization(I)) @@ -1773,147 +3300,173 @@ LoopVectorizationCostModel::getInstructionCost(Instruction *I, unsigned VF) { Type *RetTy = I->getType(); Type *VectorTy = ToVectorTy(RetTy, VF); - // TODO: We need to estimate the cost of intrinsic calls. switch (I->getOpcode()) { - case Instruction::GetElementPtr: - // We mark this instruction as zero-cost because scalar GEPs are usually - // lowered to the intruction addressing mode. At the moment we don't - // generate vector geps. - return 0; - case Instruction::Br: { - return VTTI->getCFInstrCost(I->getOpcode()); - } - case Instruction::PHI: - return 0; - 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: { - return VTTI->getArithmeticInstrCost(I->getOpcode(), VectorTy); - } - case Instruction::Select: { - SelectInst *SI = cast<SelectInst>(I); - const SCEV *CondSCEV = SE->getSCEV(SI->getCondition()); - bool ScalarCond = (SE->isLoopInvariant(CondSCEV, TheLoop)); - Type *CondTy = SI->getCondition()->getType(); - if (ScalarCond) - CondTy = VectorType::get(CondTy, VF); - - return VTTI->getCmpSelInstrCost(I->getOpcode(), VectorTy, CondTy); - } - case Instruction::ICmp: - case Instruction::FCmp: { - Type *ValTy = I->getOperand(0)->getType(); - VectorTy = ToVectorTy(ValTy, VF); - return VTTI->getCmpSelInstrCost(I->getOpcode(), VectorTy); - } - case Instruction::Store: { - StoreInst *SI = cast<StoreInst>(I); - Type *ValTy = SI->getValueOperand()->getType(); - VectorTy = ToVectorTy(ValTy, VF); - - if (VF == 1) - return VTTI->getMemoryOpCost(I->getOpcode(), ValTy, - SI->getAlignment(), SI->getPointerAddressSpace()); - - // Scalarized stores. - if (!Legal->isConsecutiveGep(SI->getPointerOperand())) { - unsigned Cost = 0; - unsigned ExtCost = VTTI->getInstrCost(Instruction::ExtractElement, - ValTy); - // The cost of extracting from the value vector. - Cost += VF * (ExtCost); - // The cost of the scalar stores. - Cost += VF * VTTI->getMemoryOpCost(I->getOpcode(), - ValTy->getScalarType(), - SI->getAlignment(), - SI->getPointerAddressSpace()); - return Cost; - } - - // Wide stores. - return VTTI->getMemoryOpCost(I->getOpcode(), VectorTy, SI->getAlignment(), - SI->getPointerAddressSpace()); - } - case Instruction::Load: { - LoadInst *LI = cast<LoadInst>(I); - - if (VF == 1) - return VTTI->getMemoryOpCost(I->getOpcode(), RetTy, - LI->getAlignment(), - LI->getPointerAddressSpace()); - - // Scalarized loads. - if (!Legal->isConsecutiveGep(LI->getPointerOperand())) { - unsigned Cost = 0; - unsigned InCost = VTTI->getInstrCost(Instruction::InsertElement, RetTy); - // The cost of inserting the loaded value into the result vector. - Cost += VF * (InCost); - // The cost of the scalar stores. - Cost += VF * VTTI->getMemoryOpCost(I->getOpcode(), - RetTy->getScalarType(), - LI->getAlignment(), - LI->getPointerAddressSpace()); - return Cost; + case Instruction::GetElementPtr: + // We mark this instruction as zero-cost because the cost of GEPs in + // vectorized code depends on whether the corresponding memory instruction + // is scalarized or not. Therefore, we handle GEPs with the memory + // instruction cost. + return 0; + case Instruction::Br: { + return TTI.getCFInstrCost(I->getOpcode()); + } + case Instruction::PHI: + //TODO: IF-converted IFs become selects. + return 0; + 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: { + // Certain instructions can be cheaper to vectorize if they have a constant + // second vector operand. One example of this are shifts on x86. + TargetTransformInfo::OperandValueKind Op1VK = + TargetTransformInfo::OK_AnyValue; + TargetTransformInfo::OperandValueKind Op2VK = + TargetTransformInfo::OK_AnyValue; + + if (isa<ConstantInt>(I->getOperand(1))) + Op2VK = TargetTransformInfo::OK_UniformConstantValue; + + return TTI.getArithmeticInstrCost(I->getOpcode(), VectorTy, Op1VK, Op2VK); + } + case Instruction::Select: { + SelectInst *SI = cast<SelectInst>(I); + const SCEV *CondSCEV = SE->getSCEV(SI->getCondition()); + bool ScalarCond = (SE->isLoopInvariant(CondSCEV, TheLoop)); + Type *CondTy = SI->getCondition()->getType(); + if (!ScalarCond) + CondTy = VectorType::get(CondTy, VF); + + return TTI.getCmpSelInstrCost(I->getOpcode(), VectorTy, CondTy); + } + case Instruction::ICmp: + case Instruction::FCmp: { + Type *ValTy = I->getOperand(0)->getType(); + VectorTy = ToVectorTy(ValTy, VF); + return TTI.getCmpSelInstrCost(I->getOpcode(), VectorTy); + } + case Instruction::Store: + case Instruction::Load: { + StoreInst *SI = dyn_cast<StoreInst>(I); + LoadInst *LI = dyn_cast<LoadInst>(I); + Type *ValTy = (SI ? SI->getValueOperand()->getType() : + LI->getType()); + VectorTy = ToVectorTy(ValTy, VF); + + unsigned Alignment = SI ? SI->getAlignment() : LI->getAlignment(); + unsigned AS = SI ? SI->getPointerAddressSpace() : + LI->getPointerAddressSpace(); + Value *Ptr = SI ? SI->getPointerOperand() : LI->getPointerOperand(); + // We add the cost of address computation here instead of with the gep + // instruction because only here we know whether the operation is + // scalarized. + if (VF == 1) + return TTI.getAddressComputationCost(VectorTy) + + TTI.getMemoryOpCost(I->getOpcode(), VectorTy, Alignment, AS); + + // Scalarized loads/stores. + int Stride = Legal->isConsecutivePtr(Ptr); + bool Reverse = Stride < 0; + if (0 == Stride) { + unsigned Cost = 0; + // The cost of extracting from the value vector and pointer vector. + Type *PtrTy = ToVectorTy(Ptr->getType(), VF); + for (unsigned i = 0; i < VF; ++i) { + // The cost of extracting the pointer operand. + Cost += TTI.getVectorInstrCost(Instruction::ExtractElement, PtrTy, i); + // In case of STORE, the cost of ExtractElement from the vector. + // In case of LOAD, the cost of InsertElement into the returned + // vector. + Cost += TTI.getVectorInstrCost(SI ? Instruction::ExtractElement : + Instruction::InsertElement, + VectorTy, i); } - // Wide loads. - return VTTI->getMemoryOpCost(I->getOpcode(), VectorTy, LI->getAlignment(), - LI->getPointerAddressSpace()); - } - 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: { - Type *SrcVecTy = ToVectorTy(I->getOperand(0)->getType(), VF); - return VTTI->getCastInstrCost(I->getOpcode(), VectorTy, SrcVecTy); + // The cost of the scalar loads/stores. + Cost += VF * TTI.getAddressComputationCost(ValTy->getScalarType()); + Cost += VF * TTI.getMemoryOpCost(I->getOpcode(), ValTy->getScalarType(), + Alignment, AS); + return Cost; } - default: { - // We are scalarizing the instruction. Return the cost of the scalar - // instruction, plus the cost of insert and extract into vector - // elements, times the vector width. - unsigned Cost = 0; - bool IsVoid = RetTy->isVoidTy(); + // Wide load/stores. + unsigned Cost = TTI.getAddressComputationCost(VectorTy); + Cost += TTI.getMemoryOpCost(I->getOpcode(), VectorTy, Alignment, AS); - unsigned InsCost = (IsVoid ? 0 : - VTTI->getInstrCost(Instruction::InsertElement, - VectorTy)); - - unsigned ExtCost = VTTI->getInstrCost(Instruction::ExtractElement, - VectorTy); + if (Reverse) + Cost += TTI.getShuffleCost(TargetTransformInfo::SK_Reverse, + VectorTy, 0); + return Cost; + } + 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: { + // We optimize the truncation of induction variable. + // The cost of these is the same as the scalar operation. + if (I->getOpcode() == Instruction::Trunc && + Legal->isInductionVariable(I->getOperand(0))) + return TTI.getCastInstrCost(I->getOpcode(), I->getType(), + I->getOperand(0)->getType()); + + Type *SrcVecTy = ToVectorTy(I->getOperand(0)->getType(), VF); + return TTI.getCastInstrCost(I->getOpcode(), VectorTy, SrcVecTy); + } + case Instruction::Call: { + CallInst *CI = cast<CallInst>(I); + Intrinsic::ID ID = getIntrinsicIDForCall(CI, TLI); + assert(ID && "Not an intrinsic call!"); + Type *RetTy = ToVectorTy(CI->getType(), VF); + SmallVector<Type*, 4> Tys; + for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) + Tys.push_back(ToVectorTy(CI->getArgOperand(i)->getType(), VF)); + return TTI.getIntrinsicInstrCost(ID, RetTy, Tys); + } + default: { + // We are scalarizing the instruction. Return the cost of the scalar + // instruction, plus the cost of insert and extract into vector + // elements, times the vector width. + unsigned Cost = 0; + + if (!RetTy->isVoidTy() && VF != 1) { + unsigned InsCost = TTI.getVectorInstrCost(Instruction::InsertElement, + VectorTy); + unsigned ExtCost = TTI.getVectorInstrCost(Instruction::ExtractElement, + VectorTy); // The cost of inserting the results plus extracting each one of the // operands. Cost += VF * (InsCost + ExtCost * I->getNumOperands()); - - // The cost of executing VF copies of the scalar instruction. - Cost += VF * VTTI->getInstrCost(I->getOpcode(), RetTy); - return Cost; } + + // The cost of executing VF copies of the scalar instruction. This opcode + // is unknown. Assume that it is the same as 'mul'. + Cost += VF * TTI.getArithmeticInstrCost(Instruction::Mul, VectorTy); + return Cost; + } }// end of switch. } @@ -1923,12 +3476,11 @@ Type* LoopVectorizationCostModel::ToVectorTy(Type *Scalar, unsigned VF) { return VectorType::get(Scalar, VF); } -} // 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_AG_DEPENDENCY(TargetTransformInfo) INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) INITIALIZE_PASS_DEPENDENCY(LoopSimplify) INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false) @@ -1939,3 +3491,14 @@ namespace llvm { } } +bool LoopVectorizationCostModel::isConsecutiveLoadOrStore(Instruction *Inst) { + // Check for a store. + if (StoreInst *ST = dyn_cast<StoreInst>(Inst)) + return Legal->isConsecutivePtr(ST->getPointerOperand()) != 0; + + // Check for a load. + if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) + return Legal->isConsecutivePtr(LI->getPointerOperand()) != 0; + + return false; +} |
