// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
-#include "LoopVectorize.h"
+//
+// This is the LLVM loop vectorizer. This pass modifies 'vectorizable' loops
+// and generates target-independent LLVM-IR.
+// The vectorizer uses the TargetTransformInfo analysis to estimate the costs
+// of instructions in order to estimate the profitability of vectorization.
+//
+// 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.
+//
+// This pass has three parts:
+// 1. The main loop pass that drives the different parts.
+// 2. LoopVectorizationLegality - A unit that checks for the legality
+// of the vectorization.
+// 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.
+//
+// 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/Transforms/Vectorize.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/EquivalenceClasses.h"
+#include "llvm/ADT/Hashing.h"
+#include "llvm/ADT/MapVector.h"
+#include "llvm/ADT/SetVector.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/Dominators.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/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/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/PatternMatch.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/TargetTransformInfo.h"
+#include "llvm/Support/ValueHandle.h"
+#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Transforms/Vectorize.h"
+#include <algorithm>
+#include <map>
+
+using namespace llvm;
+using namespace llvm::PatternMatch;
static cl::opt<unsigned>
VectorizationFactor("force-vector-width", cl::init(0), cl::Hidden,
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.
+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 memory disambiguation checks at runtime do not make more
+/// than this number of comparisons.
+static const unsigned RuntimeMemoryCheckThreshold = 8;
+
+/// Maximum simd width.
+static const unsigned MaxVectorWidth = 64;
+
+/// Maximum vectorization unroll count.
+static const unsigned MaxUnrollFactor = 16;
+
+/// The cost of a loop that is considered 'small' by the unroller.
+static const unsigned SmallLoopCost = 20;
+
namespace {
+// Forward declarations.
+class LoopVectorizationLegality;
+class LoopVectorizationCostModel;
+
+/// 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:
+/// * It inserts an epilogue loop for handling loops that don't have iteration
+/// counts that are known to be a multiple of the vectorization factor.
+/// * It handles the code generation for reduction variables.
+/// * Scalarization (implementation using scalars) of un-vectorizable
+/// instructions.
+/// InnerLoopVectorizer does not perform any vectorization-legality
+/// checks, and relies on the caller to check for the different legality
+/// 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 InnerLoopVectorizer {
+public:
+ 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.
+ 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.
+ vectorizeLoop(Legal);
+ // Register the new loop and update the analysis passes.
+ updateAnalysis();
+ }
+
+ virtual ~InnerLoopVectorizer() {}
+
+protected:
+ /// 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;
+
+ // When we if-convert we need create edge masks. We have to cache values so
+ // that we don't end up with exponential recursion/IR.
+ typedef DenseMap<std::pair<BasicBlock*, BasicBlock*>,
+ VectorParts> EdgeMaskCache;
+
+ /// 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.
+ virtual void vectorizeLoop(LoopVectorizationLegality *Legal);
+
+ /// \brief 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 fix the 'undef case'.
+ /// See PR14725.
+ void fixLCSSAPHIs();
+
+ /// 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);
+
+ /// Vectorize a single PHINode in a block. This method handles the induction
+ /// variable canonicalization. It supports both VF = 1 for unrolled loops and
+ /// arbitrary length vectors.
+ void widenPHIInstruction(Instruction *PN, VectorParts &Entry,
+ LoopVectorizationLegality *Legal,
+ unsigned UF, unsigned VF, PhiVector *PV);
+
+ /// Insert the new loop to the loop hierarchy and pass manager
+ /// and update the analysis passes.
+ void updateAnalysis();
+
+ /// This instruction is un-vectorizable. Implement it as a sequence
+ /// of scalars.
+ virtual void scalarizeInstruction(Instruction *Instr);
+
+ /// Vectorize Load and Store instructions,
+ virtual 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, ...
+ /// this is needed because each iteration in the loop corresponds to a SIMD
+ /// element.
+ virtual Value *getBroadcastInstrs(Value *V);
+
+ /// 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.
+ virtual Value *getConsecutiveVector(Value* Val, int 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.
+ VectorParts &getVectorValue(Value *V);
+
+ /// Generate a shuffle sequence that will reverse the vector Vec.
+ virtual 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;
+ }
+
+ ///\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;
+ }
+
+ 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.
+ ScalarEvolution *SE;
+ /// Loop Info.
+ LoopInfo *LI;
+ /// Dominator Tree.
+ DominatorTree *DT;
+ /// 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;
+
+protected:
+ /// The vectorization unroll factor to use. Each scalar is vectorized to this
+ /// many different vector instructions.
+ unsigned UF;
+
+ /// The builder that we use
+ IRBuilder<> Builder;
+
+ // --- Vectorization state ---
+
+ /// The vector-loop preheader.
+ BasicBlock *LoopVectorPreHeader;
+ /// The scalar-loop preheader.
+ BasicBlock *LoopScalarPreHeader;
+ /// Middle Block between the vector and the scalar.
+ BasicBlock *LoopMiddleBlock;
+ ///The ExitBlock of the scalar loop.
+ BasicBlock *LoopExitBlock;
+ ///The vector loop body.
+ BasicBlock *LoopVectorBody;
+ ///The scalar loop body.
+ BasicBlock *LoopScalarBody;
+ /// 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;
+ /// Holds the extended (to the widest induction type) start index.
+ Value *ExtendedIdx;
+ /// Maps scalars to widened vectors.
+ ValueMap WidenMap;
+ EdgeMaskCache MaskCache;
+};
+
+class InnerLoopUnroller : public InnerLoopVectorizer {
+public:
+ InnerLoopUnroller(Loop *OrigLoop, ScalarEvolution *SE, LoopInfo *LI,
+ DominatorTree *DT, DataLayout *DL,
+ const TargetLibraryInfo *TLI, unsigned UnrollFactor) :
+ InnerLoopVectorizer(OrigLoop, SE, LI, DT, DL, TLI, 1, UnrollFactor) { }
+
+private:
+ virtual void scalarizeInstruction(Instruction *Instr);
+ virtual void vectorizeMemoryInstruction(Instruction *Instr,
+ LoopVectorizationLegality *Legal);
+ virtual Value *getBroadcastInstrs(Value *V);
+ virtual Value *getConsecutiveVector(Value* Val, int StartIdx, bool Negate);
+ virtual Value *reverseVector(Value *Vec);
+};
+
+/// \brief Look for a meaningful debug location on the instruction or it's
+/// operands.
+static Instruction *getDebugLocFromInstOrOperands(Instruction *I) {
+ if (!I)
+ return I;
+
+ DebugLoc Empty;
+ if (I->getDebugLoc() != Empty)
+ return I;
+
+ for (User::op_iterator OI = I->op_begin(), OE = I->op_end(); OI != OE; ++OI) {
+ if (Instruction *OpInst = dyn_cast<Instruction>(*OI))
+ if (OpInst->getDebugLoc() != Empty)
+ return OpInst;
+ }
+
+ return I;
+}
+
+/// \brief Set the debug location in the builder using the debug location in the
+/// instruction.
+static void setDebugLocFromInst(IRBuilder<> &B, const Value *Ptr) {
+ if (const Instruction *Inst = dyn_cast_or_null<Instruction>(Ptr))
+ B.SetCurrentDebugLocation(Inst->getDebugLoc());
+ else
+ B.SetCurrentDebugLocation(DebugLoc());
+}
+
+/// LoopVectorizationLegality checks if it is legal to vectorize a loop, and
+/// to what vectorization factor.
+/// This class does not look at the profitability of vectorization, only the
+/// legality. This class has two main kinds of checks:
+/// * 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 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 *L, ScalarEvolution *SE, DataLayout *DL,
+ DominatorTree *DT, TargetLibraryInfo *TLI)
+ : TheLoop(L), SE(SE), DL(DL), DT(DT), TLI(TLI),
+ Induction(0), WidestIndTy(0), HasFunNoNaNAttr(false),
+ MaxSafeDepDistBytes(-1U) {}
+
+ /// This enum represents the kinds of reductions that we support.
+ enum ReductionKind {
+ 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_IntegerMinMax, ///< Min/max implemented in terms of select(cmp()).
+ RK_FloatAdd, ///< Sum of floats.
+ RK_FloatMult, ///< Product of floats.
+ RK_FloatMinMax ///< Min/max implemented in terms of select(cmp()).
+ };
+
+ /// 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 enum represents the kind of minmax reduction.
+ enum MinMaxReductionKind {
+ MRK_Invalid,
+ MRK_UIntMin,
+ MRK_UIntMax,
+ MRK_SIntMin,
+ MRK_SIntMax,
+ MRK_FloatMin,
+ MRK_FloatMax
+ };
+
+ /// This struct holds information about reduction variables.
+ struct ReductionDescriptor {
+ ReductionDescriptor() : StartValue(0), LoopExitInstr(0),
+ Kind(RK_NoReduction), MinMaxKind(MRK_Invalid) {}
+
+ ReductionDescriptor(Value *Start, Instruction *Exit, ReductionKind K,
+ MinMaxReductionKind MK)
+ : StartValue(Start), LoopExitInstr(Exit), Kind(K), MinMaxKind(MK) {}
+
+ // The starting value of the reduction.
+ // It does not have to be zero!
+ TrackingVH<Value> StartValue;
+ // The instruction who's value is used outside the loop.
+ Instruction *LoopExitInstr;
+ // The kind of the reduction.
+ ReductionKind Kind;
+ // If this a min/max reduction the kind of reduction.
+ MinMaxReductionKind MinMaxKind;
+ };
+
+ /// This POD struct holds information about a potential reduction operation.
+ struct ReductionInstDesc {
+ ReductionInstDesc(bool IsRedux, Instruction *I) :
+ IsReduction(IsRedux), PatternLastInst(I), MinMaxKind(MRK_Invalid) {}
+
+ ReductionInstDesc(Instruction *I, MinMaxReductionKind K) :
+ IsReduction(true), PatternLastInst(I), MinMaxKind(K) {}
+
+ // Is this instruction a reduction candidate.
+ bool IsReduction;
+ // The last instruction in a min/max pattern (select of the select(icmp())
+ // pattern), or the current reduction instruction otherwise.
+ Instruction *PatternLastInst;
+ // If this is a min/max pattern the comparison predicate.
+ MinMaxReductionKind MinMaxKind;
+ };
+
+ /// This 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();
+ IsWritePtr.clear();
+ DependencySetId.clear();
+ }
+
+ /// Insert a pointer and calculate the start and end SCEVs.
+ void insert(ScalarEvolution *SE, Loop *Lp, Value *Ptr, bool WritePtr,
+ unsigned DepSetId);
+
+ /// This flag indicates if we need to add the runtime check.
+ bool Need;
+ /// Holds the pointers that we need to check.
+ SmallVector<TrackingVH<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;
+ /// Holds the information if this pointer is used for writing to memory.
+ SmallVector<bool, 2> IsWritePtr;
+ /// Holds the id of the set of pointers that could be dependent because of a
+ /// shared underlying object.
+ SmallVector<unsigned, 2> DependencySetId;
+ };
+
+ /// A struct 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.
+ TrackingVH<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;
+
+ /// 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; }
+
+ /// Returns the reduction variables found in the loop.
+ ReductionList *getReductionVars() { return &Reductions; }
+
+ /// Returns the induction variables found in the loop.
+ InductionList *getInductionVars() { return &Inductions; }
+
+ /// Returns the widest induction type.
+ Type *getWidestInductionType() { return WidestIndTy; }
+
+ /// 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.
+ /// 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); }
+
+ /// Returns the information that we collected about runtime memory check.
+ RuntimePointerCheck *getRuntimePointerCheck() { return &PtrRtCheck; }
+
+ /// This function returns the identity element (or neutral element) for
+ /// the operation K.
+ static Constant *getReductionIdentity(ReductionKind K, Type *Tp);
+
+ unsigned getMaxSafeDepDistBytes() { return MaxSafeDepDistBytes; }
+
+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 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 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. \p SafePtrs is a list of addresses that are known to be legal
+ /// and we know that we can read from them without segfault.
+ bool blockCanBePredicated(BasicBlock *BB, SmallPtrSet<Value *, 8>& SafePtrs);
+
+ /// Returns True, if 'Phi' is the kind of reduction variable for type
+ /// 'Kind'. If this is a reduction variable, it adds it to ReductionList.
+ bool AddReductionVar(PHINode *Phi, ReductionKind Kind);
+ /// Returns a struct describing if the instruction 'I' can be a reduction
+ /// variable of type 'Kind'. If the reduction is a min/max pattern of
+ /// select(icmp()) this function advances the instruction pointer 'I' from the
+ /// compare instruction to the select instruction and stores this pointer in
+ /// 'PatternLastInst' member of the returned struct.
+ ReductionInstDesc isReductionInstr(Instruction *I, ReductionKind Kind,
+ ReductionInstDesc &Desc);
+ /// Returns true if the instruction is a Select(ICmp(X, Y), X, Y) instruction
+ /// pattern corresponding to a min(X, Y) or max(X, Y).
+ static ReductionInstDesc isMinMaxSelectCmpPattern(Instruction *I,
+ ReductionInstDesc &Prev);
+ /// Returns the induction kind of Phi. This function may return NoInduction
+ /// if the PHI is not an induction variable.
+ InductionKind isInductionVariable(PHINode *Phi);
+
+ /// The loop that we evaluate.
+ Loop *TheLoop;
+ /// Scev analysis.
+ ScalarEvolution *SE;
+ /// DataLayout analysis.
+ DataLayout *DL;
+ /// Dominators.
+ DominatorTree *DT;
+ /// Target Library Info.
+ TargetLibraryInfo *TLI;
+
+ // --- vectorization state --- //
+
+ /// 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;
+ /// Holds the widest induction type encountered.
+ Type *WidestIndTy;
+
+ /// Allowed outside users. This holds the reduction
+ /// vars which can be accessed from outside the loop.
+ SmallPtrSet<Value*, 4> AllowedExit;
+ /// This set holds the variables which are known to be uniform after
+ /// vectorization.
+ SmallPtrSet<Instruction*, 4> Uniforms;
+ /// We need to check that all of the pointers in this list are disjoint
+ /// at runtime.
+ RuntimePointerCheck PtrRtCheck;
+ /// Can we assume the absence of NaNs.
+ bool HasFunNoNaNAttr;
+
+ unsigned MaxSafeDepDistBytes;
+};
+
+/// 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
+/// TargetTransformInfo to query the different backends for the cost of
+/// different operations.
+class LoopVectorizationCostModel {
+public:
+ 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;
+ };
+
+ /// \return information about the register usage of the loop.
+ RegisterUsage calculateRegisterUsage();
+
+private:
+ /// Returns the expected execution cost. The unit of the cost does
+ /// not matter because we use the 'cost' units to compare different
+ /// vector widths. The cost that is returned is *not* normalized by
+ /// the factor width.
+ unsigned expectedCost(unsigned VF);
+
+ /// Returns the execution time cost of an instruction for a given vector
+ /// width. Vector width of one means scalar.
+ unsigned getInstructionCost(Instruction *I, unsigned VF);
+
+ /// A helper function for converting Scalar types to vector types.
+ /// If the incoming type is void, we return void. If the VF is 1, we return
+ /// 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 TargetTransformInfo &TTI;
+ /// Target data layout information.
+ DataLayout *DL;
+ /// Target Library Info.
+ const TargetLibraryInfo *TLI;
+};
+
+/// Utility class for getting and setting loop vectorizer hints in the form
+/// of loop metadata.
+struct LoopVectorizeHints {
+ /// Vectorization width.
+ unsigned Width;
+ /// Vectorization unroll factor.
+ unsigned Unroll;
+ /// Vectorization forced (-1 not selected, 0 force disabled, 1 force enabled)
+ int Force;
+
+ LoopVectorizeHints(const Loop *L, bool DisableUnrolling)
+ : Width(VectorizationFactor)
+ , Unroll(DisableUnrolling ? 1 : VectorizationUnroll)
+ , Force(-1)
+ , LoopID(L->getLoopID()) {
+ getHints(L);
+ // The command line options override any loop metadata except for when
+ // width == 1 which is used to indicate the loop is already vectorized.
+ if (VectorizationFactor.getNumOccurrences() > 0 && Width != 1)
+ Width = VectorizationFactor;
+ if (VectorizationUnroll.getNumOccurrences() > 0)
+ Unroll = VectorizationUnroll;
+
+ DEBUG(if (DisableUnrolling && Unroll == 1)
+ dbgs() << "LV: Unrolling disabled by the pass manager\n");
+ }
+
+ /// Return the loop vectorizer metadata prefix.
+ static StringRef Prefix() { return "llvm.vectorizer."; }
+
+ MDNode *createHint(LLVMContext &Context, StringRef Name, unsigned V) {
+ SmallVector<Value*, 2> Vals;
+ Vals.push_back(MDString::get(Context, Name));
+ Vals.push_back(ConstantInt::get(Type::getInt32Ty(Context), V));
+ return MDNode::get(Context, Vals);
+ }
+
+ /// Mark the loop L as already vectorized by setting the width to 1.
+ void setAlreadyVectorized(Loop *L) {
+ LLVMContext &Context = L->getHeader()->getContext();
+
+ Width = 1;
+
+ // Create a new loop id with one more operand for the already_vectorized
+ // hint. If the loop already has a loop id then copy the existing operands.
+ SmallVector<Value*, 4> Vals(1);
+ if (LoopID)
+ for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i)
+ Vals.push_back(LoopID->getOperand(i));
+
+ Vals.push_back(createHint(Context, Twine(Prefix(), "width").str(), Width));
+ Vals.push_back(createHint(Context, Twine(Prefix(), "unroll").str(), 1));
+
+ MDNode *NewLoopID = MDNode::get(Context, Vals);
+ // Set operand 0 to refer to the loop id itself.
+ NewLoopID->replaceOperandWith(0, NewLoopID);
+
+ L->setLoopID(NewLoopID);
+ if (LoopID)
+ LoopID->replaceAllUsesWith(NewLoopID);
+
+ LoopID = NewLoopID;
+ }
+
+private:
+ MDNode *LoopID;
+
+ /// Find hints specified in the loop metadata.
+ void getHints(const Loop *L) {
+ if (!LoopID)
+ return;
+
+ // First operand should refer to the loop id itself.
+ assert(LoopID->getNumOperands() > 0 && "requires at least one operand");
+ assert(LoopID->getOperand(0) == LoopID && "invalid loop id");
+
+ for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i) {
+ const MDString *S = 0;
+ SmallVector<Value*, 4> Args;
+
+ // The expected hint is either a MDString or a MDNode with the first
+ // operand a MDString.
+ if (const MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i))) {
+ if (!MD || MD->getNumOperands() == 0)
+ continue;
+ S = dyn_cast<MDString>(MD->getOperand(0));
+ for (unsigned i = 1, ie = MD->getNumOperands(); i < ie; ++i)
+ Args.push_back(MD->getOperand(i));
+ } else {
+ S = dyn_cast<MDString>(LoopID->getOperand(i));
+ assert(Args.size() == 0 && "too many arguments for MDString");
+ }
+
+ if (!S)
+ continue;
+
+ // Check if the hint starts with the vectorizer prefix.
+ StringRef Hint = S->getString();
+ if (!Hint.startswith(Prefix()))
+ continue;
+ // Remove the prefix.
+ Hint = Hint.substr(Prefix().size(), StringRef::npos);
+
+ if (Args.size() == 1)
+ getHint(Hint, Args[0]);
+ }
+ }
+
+ // Check string hint with one operand.
+ void getHint(StringRef Hint, Value *Arg) {
+ const ConstantInt *C = dyn_cast<ConstantInt>(Arg);
+ if (!C) return;
+ unsigned Val = C->getZExtValue();
+
+ if (Hint == "width") {
+ if (isPowerOf2_32(Val) && Val <= MaxVectorWidth)
+ Width = Val;
+ else
+ DEBUG(dbgs() << "LV: ignoring invalid width hint metadata\n");
+ } else if (Hint == "unroll") {
+ if (isPowerOf2_32(Val) && Val <= MaxUnrollFactor)
+ Unroll = Val;
+ else
+ DEBUG(dbgs() << "LV: ignoring invalid unroll hint metadata\n");
+ } else if (Hint == "enable") {
+ if (C->getBitWidth() == 1)
+ Force = Val;
+ else
+ DEBUG(dbgs() << "LV: ignoring invalid enable hint metadata\n");
+ } else {
+ DEBUG(dbgs() << "LV: ignoring unknown hint " << Hint << '\n');
+ }
+ }
+};
+
/// The LoopVectorize Pass.
struct LoopVectorize : public LoopPass {
/// Pass identification, replacement for typeid
static char ID;
- explicit LoopVectorize() : LoopPass(ID) {
+ explicit LoopVectorize(bool NoUnrolling = false, bool AlwaysVectorize = true)
+ : LoopPass(ID),
+ DisableUnrolling(NoUnrolling),
+ AlwaysVectorize(AlwaysVectorize) {
initializeLoopVectorizePass(*PassRegistry::getPassRegistry());
}
LoopInfo *LI;
TargetTransformInfo *TTI;
DominatorTree *DT;
+ TargetLibraryInfo *TLI;
+ bool DisableUnrolling;
+ bool AlwaysVectorize;
virtual bool runOnLoop(Loop *L, LPPassManager &LPM) {
// We only vectorize innermost loops.
SE = &getAnalysis<ScalarEvolution>();
DL = getAnalysisIfAvailable<DataLayout>();
LI = &getAnalysis<LoopInfo>();
- TTI = getAnalysisIfAvailable<TargetTransformInfo>();
+ TTI = &getAnalysis<TargetTransformInfo>();
DT = &getAnalysis<DominatorTree>();
+ TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
+
+ // If the target claims to have no vector registers don't attempt
+ // vectorization.
+ if (!TTI->getNumberOfRegisters(true))
+ return false;
+
+ if (DL == NULL) {
+ DEBUG(dbgs() << "LV: Not vectorizing: Missing data layout\n");
+ return false;
+ }
DEBUG(dbgs() << "LV: Checking a loop in \"" <<
L->getHeader()->getParent()->getName() << "\"\n");
+ LoopVectorizeHints Hints(L, DisableUnrolling);
+
+ if (Hints.Force == 0) {
+ DEBUG(dbgs() << "LV: Not vectorizing: #pragma vectorize disable.\n");
+ return false;
+ }
+
+ if (!AlwaysVectorize && Hints.Force != 1) {
+ DEBUG(dbgs() << "LV: Not vectorizing: No #pragma vectorize enable.\n");
+ return false;
+ }
+
+ if (Hints.Width == 1 && Hints.Unroll == 1) {
+ DEBUG(dbgs() << "LV: Not vectorizing: Disabled/already vectorized.\n");
+ return false;
+ }
+
// Check if it is legal to vectorize the loop.
- LoopVectorizationLegality LVL(L, SE, DL, DT);
+ LoopVectorizationLegality LVL(L, SE, DL, DT, TLI);
if (!LVL.canVectorize()) {
- DEBUG(dbgs() << "LV: Not vectorizing.\n");
+ DEBUG(dbgs() << "LV: Not vectorizing: Cannot prove legality.\n");
return false;
}
- // Select the preffered vectorization factor.
- const VectorTargetTransformInfo *VTTI = 0;
- if (TTI)
- VTTI = TTI->getVectorTargetTransformInfo();
// Use the cost model.
- LoopVectorizationCostModel CM(L, SE, LI, &LVL, VTTI);
+ LoopVectorizationCostModel CM(L, SE, LI, &LVL, *TTI, DL, TLI);
- // Check the function attribues to find out if this function should be
+ // 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 OptForSize = Hints.Force != 1 &&
+ F->getAttributes().hasAttribute(FnIndex, SzAttr);
bool NoFloat = F->getAttributes().hasAttribute(FnIndex, FlAttr);
if (NoFloat) {
return false;
}
- unsigned VF = CM.selectVectorizationFactor(OptForSize, VectorizationFactor);
- unsigned UF = CM.selectUnrollFactor(OptForSize, VectorizationUnroll);
+ // Select the optimal vectorization factor.
+ LoopVectorizationCostModel::VectorizationFactor VF;
+ VF = CM.selectVectorizationFactor(OptForSize, Hints.Width);
+ // Select the unroll factor.
+ unsigned UF = CM.selectUnrollFactor(OptForSize, Hints.Unroll, VF.Width,
+ VF.Cost);
+
+ DEBUG(dbgs() << "LV: Found a vectorizable loop ("<< VF.Width << ") in "<<
+ F->getParent()->getModuleIdentifier() << '\n');
+ DEBUG(dbgs() << "LV: Unroll Factor is " << UF << '\n');
- if (VF == 1) {
+ if (VF.Width == 1) {
DEBUG(dbgs() << "LV: Vectorization is possible but not beneficial.\n");
- return false;
+ if (UF == 1)
+ return false;
+ DEBUG(dbgs() << "LV: Trying to at least unroll the loops.\n");
+ // We decided not to vectorize, but we may want to unroll.
+ InnerLoopUnroller Unroller(L, SE, LI, DT, DL, TLI, UF);
+ Unroller.vectorize(&LVL);
+ } else {
+ // 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(dbgs() << "LV: Found a vectorizable loop ("<< VF << ") 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.
- InnerLoopVectorizer LB(L, SE, LI, DT, DL, VF, UF);
- LB.vectorize(&LVL);
+ // Mark the loop as already vectorized to avoid vectorizing again.
+ Hints.setAlreadyVectorized(L);
DEBUG(verifyFunction(*L->getHeader()->getParent()));
return true;
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>();
}
};
-}// namespace
+} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Implementation of LoopVectorizationLegality, InnerLoopVectorizer and
void
LoopVectorizationLegality::RuntimePointerCheck::insert(ScalarEvolution *SE,
- Loop *Lp, Value *Ptr) {
+ Loop *Lp, Value *Ptr,
+ bool WritePtr,
+ unsigned DepSetId) {
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 *Ex = SE->getBackedgeTakenCount(Lp);
const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE);
Pointers.push_back(Ptr);
Starts.push_back(AR->getStart());
Ends.push_back(ScEnd);
+ IsWritePtr.push_back(WritePtr);
+ DependencySetId.push_back(DepSetId);
}
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.
+ IRBuilder<>::InsertPointGuard Guard(Builder);
if (Invariant)
Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
// Broadcast the scalar into all locations in the vector.
Value *Shuf = Builder.CreateVectorSplat(VF, V, "broadcast");
- // Restore the builder insertion point.
- if (Invariant)
- Builder.SetInsertPoint(Loc);
-
return Shuf;
}
-Value *InnerLoopVectorizer::getConsecutiveVector(Value* Val, unsigned StartIdx,
+Value *InnerLoopVectorizer::getConsecutiveVector(Value* Val, int StartIdx,
bool Negate) {
assert(Val->getType()->isVectorTy() && "Must be a vector");
assert(Val->getType()->getScalarType()->isIntegerTy() &&
// Create a vector of consecutive numbers from zero to VF.
for (int i = 0; i < VLen; ++i) {
- int Idx = Negate ? (-i): i;
- Indices.push_back(ConstantInt::get(ITy, StartIdx + Idx));
+ int64_t Idx = Negate ? (-i) : i;
+ Indices.push_back(ConstantInt::get(ITy, StartIdx + Idx, Negate));
}
// Add the consecutive indices to the vector value.
return Builder.CreateAdd(Val, Cv, "induction");
}
+/// \brief Find the operand of the GEP that should be checked for consecutive
+/// stores. This ignores trailing indices that have no effect on the final
+/// pointer.
+static unsigned getGEPInductionOperand(DataLayout *DL,
+ const GetElementPtrInst *Gep) {
+ unsigned LastOperand = Gep->getNumOperands() - 1;
+ unsigned GEPAllocSize = DL->getTypeAllocSize(
+ cast<PointerType>(Gep->getType()->getScalarType())->getElementType());
+
+ // Walk backwards and try to peel off zeros.
+ while (LastOperand > 1 && match(Gep->getOperand(LastOperand), m_Zero())) {
+ // Find the type we're currently indexing into.
+ gep_type_iterator GEPTI = gep_type_begin(Gep);
+ std::advance(GEPTI, LastOperand - 1);
+
+ // If it's a type with the same allocation size as the result of the GEP we
+ // can peel off the zero index.
+ if (DL->getTypeAllocSize(*GEPTI) != GEPAllocSize)
+ break;
+ --LastOperand;
+ }
+
+ return LastOperand;
+}
+
int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
- assert(Ptr->getType()->isPointerTy() && "Unexpected non ptr");
+ assert(Ptr->getType()->isPointerTy() && "Unexpected non-ptr");
+ // Make sure that the pointer does not point to structs.
+ if (Ptr->getType()->getPointerElementType()->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 (PtrInduction == II.IK)
+ if (IK_PtrInduction == II.IK)
return 1;
+ else if (IK_ReversePtrInduction == II.IK)
+ return -1;
}
GetElementPtrInst *Gep = dyn_cast_or_null<GetElementPtrInst>(Ptr);
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;
+ }
+
+ unsigned InductionOperand = getGEPInductionOperand(DL, Gep);
- // 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))
+ // Check that all of the gep indices are uniform except for our induction
+ // operand.
+ for (unsigned i = 0; i != NumOperands; ++i)
+ if (i != InductionOperand &&
+ !SE->isLoopInvariant(SE->getSCEV(Gep->getOperand(i)), TheLoop))
return 0;
- // We can emit wide load/stores only if the last index is the induction
- // variable.
- const SCEV *Last = SE->getSCEV(LastIndex);
+ // We can emit wide load/stores only if the last non-zero index is the
+ // induction variable.
+ const SCEV *Last = SE->getSCEV(Gep->getOperand(InductionOperand));
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Last)) {
const SCEV *Step = AR->getStepRecurrence(*SE);
// 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);
- WidenMap.splat(V, B);
- return WidenMap.get(V);
-}
-
-Constant*
-InnerLoopVectorizer::getUniformVector(unsigned Val, Type* ScalarTy) {
- return ConstantVector::getSplat(VF, ConstantInt::get(ScalarTy, Val, true));
+ return WidenMap.splat(V, B);
}
Value *InnerLoopVectorizer::reverseVector(Value *Vec) {
"reverse");
}
+
+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();
+ // An alignment of 0 means target abi alignment. We need to use the scalar's
+ // target abi alignment in such a case.
+ if (!Alignment)
+ Alignment = DL->getABITypeAlignment(ScalarDataTy);
+ unsigned AddressSpace = Ptr->getType()->getPointerAddressSpace();
+ unsigned ScalarAllocatedSize = DL->getTypeAllocSize(ScalarDataTy);
+ unsigned VectorElementSize = DL->getTypeStoreSize(DataTy)/VF;
+
+ if (ScalarAllocatedSize != VectorElementSize)
+ return scalarizeInstruction(Instr);
+
+ // If the pointer is loop invariant or if it is non-consecutive,
+ // scalarize the load.
+ int ConsecutiveStride = Legal->isConsecutivePtr(Ptr);
+ bool Reverse = ConsecutiveStride < 0;
+ bool UniformLoad = LI && Legal->isUniform(Ptr);
+ if (!ConsecutiveStride || 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())) {
+ setDebugLocFromInst(Builder, Gep);
+ 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) {
+ setDebugLocFromInst(Builder, 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();
+ unsigned InductionOperand = getGEPInductionOperand(DL, Gep);
+ // Create the new GEP with the new induction variable.
+ GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
+
+ for (unsigned i = 0; i < NumOperands; ++i) {
+ Value *GepOperand = Gep->getOperand(i);
+ Instruction *GepOperandInst = dyn_cast<Instruction>(GepOperand);
+
+ // Update last index or loop invariant instruction anchored in loop.
+ if (i == InductionOperand ||
+ (GepOperandInst && OrigLoop->contains(GepOperandInst))) {
+ assert((i == InductionOperand ||
+ SE->isLoopInvariant(SE->getSCEV(GepOperandInst), OrigLoop)) &&
+ "Must be last index or loop invariant");
+
+ VectorParts &GEPParts = getVectorValue(GepOperand);
+ Value *Index = GEPParts[0];
+ Index = Builder.CreateExtractElement(Index, Zero);
+ Gep2->setOperand(i, Index);
+ Gep2->setName("gep.indvar.idx");
+ }
+ }
+ Ptr = Builder.Insert(Gep2);
+ } else {
+ // Use the induction element ptr.
+ assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
+ setDebugLocFromInst(Builder, 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");
+ setDebugLocFromInst(Builder, SI);
+ // We don't want to update the value in the map as it might be used in
+ // another expression. So don't use a reference type for "StoredVal".
+ 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(AddressSpace));
+ Builder.CreateStore(StoredVal[Part], VecPtr)->setAlignment(Alignment);
+ }
+ return;
+ }
+
+ // Handle loads.
+ assert(LI && "Must have a load instruction");
+ setDebugLocFromInst(Builder, LI);
+ 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(AddressSpace));
+ 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<VectorParts, 4> Params;
+ setDebugLocFromInst(Builder, Instr);
+
// Find all of the vectorized parameters.
for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) {
Value *SrcOp = Instr->getOperand(op);
// 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 Width = 0; Width < VF; ++Width) {
- // For each vector unroll 'part':
- for (unsigned Part = 0; Part < UF; ++Part) {
+ // For each vector unroll 'part':
+ for (unsigned Part = 0; Part < UF; ++Part) {
+ // For each scalar that we create:
+ for (unsigned Width = 0; Width < VF; ++Width) {
Instruction *Cloned = Instr->clone();
if (!IsVoidRetTy)
Cloned->setName(Instr->getName() + ".cloned");
- // Replace the operands of the cloned instrucions with extracted scalars.
+ // Replace the operands of the cloned instructions 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.
}
}
-Value*
+Instruction *
InnerLoopVectorizer::addRuntimeCheck(LoopVectorizationLegality *Legal,
Instruction *Loc) {
LoopVectorizationLegality::RuntimePointerCheck *PtrRtCheck =
if (!PtrRtCheck->Need)
return NULL;
- Value *MemoryRuntimeCheck = 0;
unsigned NumPointers = PtrRtCheck->Pointers.size();
- SmallVector<Value* , 2> Starts;
- SmallVector<Value* , 2> Ends;
+ SmallVector<TrackingVH<Value> , 2> Starts;
+ SmallVector<TrackingVH<Value> , 2> Ends;
+ LLVMContext &Ctx = Loc->getContext();
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);
Starts.push_back(Ptr);
Ends.push_back(Ptr);
} else {
- DEBUG(dbgs() << "LV: Adding RT check for range:" << *Ptr <<"\n");
+ DEBUG(dbgs() << "LV: Adding RT check for range:" << *Ptr << '\n');
+ unsigned AS = Ptr->getType()->getPointerAddressSpace();
+
+ // Use this type for pointer arithmetic.
+ Type *PtrArithTy = Type::getInt8PtrTy(Ctx, AS);
Value *Start = Exp.expandCodeFor(PtrRtCheck->Starts[i], PtrArithTy, Loc);
Value *End = Exp.expandCodeFor(PtrRtCheck->Ends[i], PtrArithTy, Loc);
}
}
+ IRBuilder<> ChkBuilder(Loc);
+ // Our instructions might fold to a constant.
+ Value *MemoryRuntimeCheck = 0;
for (unsigned i = 0; i < NumPointers; ++i) {
for (unsigned j = i+1; j < NumPointers; ++j) {
- Instruction::CastOps Op = Instruction::BitCast;
- Value *Start0 = CastInst::Create(Op, Starts[i], PtrArithTy, "bc", Loc);
- Value *Start1 = CastInst::Create(Op, Starts[j], PtrArithTy, "bc", Loc);
- Value *End0 = CastInst::Create(Op, Ends[i], PtrArithTy, "bc", Loc);
- Value *End1 = CastInst::Create(Op, Ends[j], PtrArithTy, "bc", Loc);
-
- Value *Cmp0 = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_ULE,
- Start0, End1, "bound0", Loc);
- Value *Cmp1 = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_ULE,
- Start1, End0, "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;
+ // No need to check if two readonly pointers intersect.
+ if (!PtrRtCheck->IsWritePtr[i] && !PtrRtCheck->IsWritePtr[j])
+ continue;
+
+ // Only need to check pointers between two different dependency sets.
+ if (PtrRtCheck->DependencySetId[i] == PtrRtCheck->DependencySetId[j])
+ continue;
+
+ unsigned AS0 = Starts[i]->getType()->getPointerAddressSpace();
+ unsigned AS1 = Starts[j]->getType()->getPointerAddressSpace();
+ assert((AS0 == Ends[j]->getType()->getPointerAddressSpace()) &&
+ (AS1 == Ends[i]->getType()->getPointerAddressSpace()) &&
+ "Trying to bounds check pointers with different address spaces");
+
+ Type *PtrArithTy0 = Type::getInt8PtrTy(Ctx, AS0);
+ Type *PtrArithTy1 = Type::getInt8PtrTy(Ctx, AS1);
+
+ Value *Start0 = ChkBuilder.CreateBitCast(Starts[i], PtrArithTy0, "bc");
+ Value *Start1 = ChkBuilder.CreateBitCast(Starts[j], PtrArithTy1, "bc");
+ Value *End0 = ChkBuilder.CreateBitCast(Ends[i], PtrArithTy1, "bc");
+ Value *End1 = ChkBuilder.CreateBitCast(Ends[j], PtrArithTy0, "bc");
+
+ 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");
+ MemoryRuntimeCheck = IsConflict;
}
}
- return MemoryRuntimeCheck;
+ // We have to do this trickery because the IRBuilder might fold the check to a
+ // constant expression in which case there is no Instruction anchored in a
+ // the block.
+ Instruction *Check = BinaryOperator::CreateAnd(MemoryRuntimeCheck,
+ ConstantInt::getTrue(Ctx));
+ ChkBuilder.Insert(Check, "memcheck.conflict");
+ return Check;
}
void
the vectorized instructions while the old loop will continue to run the
scalar remainder.
- [ ] <-- vector loop bypass.
+ [ ] <-- vector loop bypass (may consist of multiple blocks).
/ |
/ v
| [ ] <-- vector pre header.
// induction variables. In the code below we also support a case where we
// don't have a single induction variable.
OldInduction = Legal->getInduction();
- Type *IdxTy = OldInduction ? OldInduction->getType() :
- DL->getIntPtrType(SE->getContext());
+ Type *IdxTy = Legal->getWidestInductionType();
// Find the loop boundaries.
- const SCEV *ExitCount = SE->getExitCount(OrigLoop, OrigLoop->getLoopLatch());
+ const SCEV *ExitCount = SE->getBackedgeTakenCount(OrigLoop);
assert(ExitCount != SE->getCouldNotCompute() && "Invalid loop count");
+ // The exit count might have the type of i64 while the phi is i32. This can
+ // happen if we have an induction variable that is sign extended before the
+ // compare. The only way that we get a backedge taken count is that the
+ // induction variable was signed and as such will not overflow. In such a case
+ // truncation is legal.
+ if (ExitCount->getType()->getPrimitiveSizeInBits() >
+ IdxTy->getPrimitiveSizeInBits())
+ ExitCount = SE->getTruncateOrNoop(ExitCount, IdxTy);
+
+ ExitCount = SE->getNoopOrZeroExtend(ExitCount, IdxTy);
// Get the total trip count from the count by adding 1.
ExitCount = SE->getAddExpr(ExitCount,
SE->getConstant(ExitCount->getType(), 1));
// 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);
+ Builder.SetInsertPoint(BypassBlock->getTerminator());
+ Value *StartIdx = ExtendedIdx = OldInduction ?
+ Builder.CreateZExt(OldInduction->getIncomingValueForBlock(BypassBlock),
+ IdxTy):
+ ConstantInt::get(IdxTy, 0);
assert(BypassBlock && "Invalid loop structure");
-
- // Generate the code that checks in runtime if arrays overlap.
- Value *MemoryRuntimeCheck = addRuntimeCheck(Legal,
- BypassBlock->getTerminator());
+ LoopBypassBlocks.push_back(BypassBlock);
// Split the single block loop into the two loop structure described above.
BasicBlock *VectorPH =
BasicBlock *ScalarPH =
MiddleBlock->splitBasicBlock(MiddleBlock->getTerminator(), "scalar.ph");
- // This is the location in which we add all of the logic for bypassing
- // the new vector loop.
- Instruction *Loc = BypassBlock->getTerminator();
+ // Create and register the new vector loop.
+ Loop* Lp = new Loop();
+ Loop *ParentLoop = OrigLoop->getParentLoop();
+
+ // Insert the new loop into the loop nest and register the new basic blocks
+ // before calling any utilities such as SCEV that require valid LoopInfo.
+ if (ParentLoop) {
+ ParentLoop->addChildLoop(Lp);
+ ParentLoop->addBasicBlockToLoop(ScalarPH, LI->getBase());
+ ParentLoop->addBasicBlockToLoop(VectorPH, LI->getBase());
+ ParentLoop->addBasicBlockToLoop(MiddleBlock, LI->getBase());
+ } else {
+ LI->addTopLevelLoop(Lp);
+ }
+ Lp->addBasicBlockToLoop(VecBody, LI->getBase());
// Use this IR builder to create the loop instructions (Phi, Br, Cmp)
// inside the loop.
- Builder.SetInsertPoint(VecBody->getFirstInsertionPt());
+ Builder.SetInsertPoint(VecBody->getFirstNonPHI());
// Generate the induction variable.
+ setDebugLocFromInst(Builder, getDebugLocFromInstOrOperands(OldInduction));
Induction = Builder.CreatePHI(IdxTy, 2, "index");
// 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);
+ // This is the IR builder that we use to add all of the logic for bypassing
+ // the new vector loop.
+ IRBuilder<> BypassBuilder(BypassBlock->getTerminator());
+ setDebugLocFromInst(BypassBuilder,
+ getDebugLocFromInstOrOperands(OldInduction));
+
// 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 = CastInst::CreatePointerCast(Count, IdxTy, "ptrcnt.to.int", Loc);
+ Count = BypassBuilder.CreatePointerCast(Count, IdxTy, "ptrcnt.to.int");
else
- Count = CastInst::CreateZExtOrBitCast(Count, IdxTy, "zext.cnt", Loc);
+ 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.
- Value *R = BinaryOperator::CreateURem(Count, Step, "n.mod.vf", Loc);
- Value *CountRoundDown = BinaryOperator::CreateSub(Count, R, "n.vec", Loc);
- Value *IdxEndRoundDown = BinaryOperator::CreateAdd(CountRoundDown, StartIdx,
- "end.idx.rnd.down", 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 = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ,
- IdxEndRoundDown,
- StartIdx,
- "cmp.zero", Loc);
-
- // If we are using memory runtime checks, include them in.
- if (MemoryRuntimeCheck)
- Cmp = BinaryOperator::Create(Instruction::Or, Cmp, MemoryRuntimeCheck,
- "CntOrMem", Loc);
+ 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");
+ if (ParentLoop)
+ ParentLoop->addBasicBlockToLoop(CheckBlock, LI->getBase());
+ 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;
+ }
- BranchInst::Create(MiddleBlock, VectorPH, Cmp, Loc);
- // Remove the old terminator.
- Loc->eraseFromParent();
+ LastBypassBlock->getTerminator()->eraseFromParent();
+ BranchInst::Create(MiddleBlock, VectorPH, Cmp,
+ LastBypassBlock);
// We are going to resume the execution of the scalar loop.
// Go over all of the induction variables that we found and fix the
PHINode *ResumeIndex = 0;
LoopVectorizationLegality::InductionList::iterator I, E;
LoopVectorizationLegality::InductionList *List = Legal->getInductionVars();
+ // Set builder to point to last bypass block.
+ BypassBuilder.SetInsertPoint(LoopBypassBlocks.back()->getTerminator());
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",
+
+ Type *ResumeValTy = (OrigPhi == OldInduction) ? IdxTy : OrigPhi->getType();
+ PHINode *ResumeVal = PHINode::Create(ResumeValTy, 2, "resume.val",
MiddleBlock->getTerminator());
+ // We might have extended the type of the induction variable but we need a
+ // truncated version for the scalar loop.
+ PHINode *TruncResumeVal = (OrigPhi == OldInduction) ?
+ PHINode::Create(OrigPhi->getType(), 2, "trunc.resume.val",
+ MiddleBlock->getTerminator()) : 0;
+
Value *EndValue = 0;
switch (II.IK) {
- case LoopVectorizationLegality::NoInduction:
+ case LoopVectorizationLegality::IK_NoInduction:
llvm_unreachable("Unknown induction");
- case LoopVectorizationLegality::IntInduction: {
- // Handle the integer induction counter:
+ 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;
+
+ // We have the canonical induction variable.
+ if (OrigPhi == OldInduction) {
+ // Create a truncated version of the resume value for the scalar loop,
+ // we might have promoted the type to a larger width.
+ EndValue =
+ BypassBuilder.CreateTrunc(IdxEndRoundDown, OrigPhi->getType());
+ // 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)
+ TruncResumeVal->addIncoming(II.StartValue, LoopBypassBlocks[I]);
+ TruncResumeVal->addIncoming(EndValue, VecBody);
+
+ // We know what the end value is.
+ EndValue = IdxEndRoundDown;
+ // We also know which PHI node holds it.
+ ResumeIndex = ResumeVal;
+ break;
+ }
+
+ // Not the canonical induction variable - add the vector loop count to the
+ // start value.
+ Value *CRD = BypassBuilder.CreateSExtOrTrunc(CountRoundDown,
+ II.StartValue->getType(),
+ "cast.crd");
+ EndValue = BypassBuilder.CreateAdd(CRD, II.StartValue , "ind.end");
break;
}
- case LoopVectorizationLegality::ReverseIntInduction: {
+ 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", BypassBlock->getTerminator());
- else if (CRDSize < IISize)
- CRD = CastInst::Create(Instruction::SExt, CountRoundDown,
- II.StartValue->getType(),
- "sext.crd", BypassBlock->getTerminator());
- // Handle reverse integer induction counter:
- EndValue = BinaryOperator::CreateSub(II.StartValue, CRD, "rev.ind.end",
- BypassBlock->getTerminator());
+ Value *CRD = BypassBuilder.CreateSExtOrTrunc(CountRoundDown,
+ II.StartValue->getType(),
+ "cast.crd");
+ // Handle reverse integer induction counter.
+ EndValue = BypassBuilder.CreateSub(II.StartValue, CRD, "rev.ind.end");
break;
}
- case LoopVectorizationLegality::PtrInduction: {
+ case LoopVectorizationLegality::IK_PtrInduction: {
// For pointer induction variables, calculate the offset using
// the end index.
- EndValue = GetElementPtrInst::Create(II.StartValue, CountRoundDown,
- "ptr.ind.end",
- BypassBlock->getTerminator());
+ EndValue = BypassBuilder.CreateGEP(II.StartValue, CountRoundDown,
+ "ptr.ind.end");
+ 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 = BypassBuilder.CreateSub(Zero, CountRoundDown,
+ "rev.ind.end");
+ EndValue = BypassBuilder.CreateGEP(II.StartValue, NegIdx,
+ "rev.ptr.ind.end");
break;
}
}// end of case
// The new PHI merges the original incoming value, in case of a bypass,
// or the value at the end of the vectorized loop.
- ResumeVal->addIncoming(II.StartValue, BypassBlock);
+ for (unsigned I = 0, E = LoopBypassBlocks.size(); I != E; ++I) {
+ if (OrigPhi == OldInduction)
+ ResumeVal->addIncoming(StartIdx, LoopBypassBlocks[I]);
+ else
+ 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);
+ // The old inductions phi node in the scalar body needs the truncated value.
+ if (OrigPhi == OldInduction)
+ OrigPhi->setIncomingValue(BlockIdx, TruncResumeVal);
+ else
+ OrigPhi->setIncomingValue(BlockIdx, ResumeVal);
}
// If we are generating a new induction variable then we also need to
assert(!ResumeIndex && "Unexpected resume value found");
ResumeIndex = PHINode::Create(IdxTy, 2, "new.indc.resume.val",
MiddleBlock->getTerminator());
- ResumeIndex->addIncoming(StartIdx, BypassBlock);
+ for (unsigned I = 0, E = LoopBypassBlocks.size(); I != E; ++I)
+ ResumeIndex->addIncoming(StartIdx, LoopBypassBlocks[I]);
ResumeIndex->addIncoming(IdxEndRoundDown, VecBody);
}
// Get ready to start creating new instructions into the vectorized body.
Builder.SetInsertPoint(VecBody->getFirstInsertionPt());
- // Create and register the new vector loop.
- Loop* Lp = new Loop();
- Loop *ParentLoop = OrigLoop->getParentLoop();
-
- // Insert the new loop into the loop nest and register the new basic blocks.
- if (ParentLoop) {
- ParentLoop->addChildLoop(Lp);
- 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;
LoopExitBlock = ExitBlock;
LoopVectorBody = VecBody;
LoopScalarBody = OldBasicBlock;
- LoopBypassBlock = BypassBlock;
+
+ LoopVectorizeHints Hints(Lp, true);
+ Hints.setAlreadyVectorized(Lp);
}
/// This function returns the identity element (or neutral element) for
/// the operation K.
-static unsigned
-getReductionIdentity(LoopVectorizationLegality::ReductionKind K) {
+Constant*
+LoopVectorizationLegality::getReductionIdentity(ReductionKind K, Type *Tp) {
switch (K) {
- case LoopVectorizationLegality::IntegerXor:
- case LoopVectorizationLegality::IntegerAdd:
- case LoopVectorizationLegality::IntegerOr:
+ case RK_IntegerXor:
+ case RK_IntegerAdd:
+ case RK_IntegerOr:
// Adding, Xoring, Oring zero to a number does not change it.
- return 0;
- case LoopVectorizationLegality::IntegerMult:
+ return ConstantInt::get(Tp, 0);
+ case RK_IntegerMult:
// Multiplying a number by 1 does not change it.
- return 1;
- case LoopVectorizationLegality::IntegerAnd:
+ return ConstantInt::get(Tp, 1);
+ case RK_IntegerAnd:
// AND-ing a number with an all-1 value does not change it.
- return -1;
+ return ConstantInt::get(Tp, -1, true);
+ case RK_FloatMult:
+ // Multiplying a number by 1 does not change it.
+ return ConstantFP::get(Tp, 1.0L);
+ case RK_FloatAdd:
+ // Adding zero to a number does not change it.
+ return ConstantFP::get(Tp, 0.0L);
default:
llvm_unreachable("Unknown reduction kind");
}
}
-static bool
-isTriviallyVectorizableIntrinsic(Instruction *Inst) {
- IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst);
- if (!II)
- return false;
- 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 true;
- default:
- return false;
- }
- return false;
+static Intrinsic::ID checkUnaryFloatSignature(const CallInst &I,
+ Intrinsic::ID ValidIntrinsicID) {
+ if (I.getNumArgOperands() != 1 ||
+ !I.getArgOperand(0)->getType()->isFloatingPointTy() ||
+ I.getType() != I.getArgOperand(0)->getType() ||
+ !I.onlyReadsMemory())
+ return Intrinsic::not_intrinsic;
+
+ return ValidIntrinsicID;
}
-void
-InnerLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) {
- //===------------------------------------------------===//
- //
- // Notice: any optimization or new instruction that go
- // into the code below should be also be implemented in
- // the cost-model.
- //
- //===------------------------------------------------===//
- BasicBlock &BB = *OrigLoop->getHeader();
- Constant *Zero =
- ConstantInt::get(IntegerType::getInt32Ty(BB.getContext()), 0);
+static Intrinsic::ID checkBinaryFloatSignature(const CallInst &I,
+ Intrinsic::ID ValidIntrinsicID) {
+ if (I.getNumArgOperands() != 2 ||
+ !I.getArgOperand(0)->getType()->isFloatingPointTy() ||
+ !I.getArgOperand(1)->getType()->isFloatingPointTy() ||
+ I.getType() != I.getArgOperand(0)->getType() ||
+ I.getType() != I.getArgOperand(1)->getType() ||
+ !I.onlyReadsMemory())
+ return Intrinsic::not_intrinsic;
+
+ return ValidIntrinsicID;
+}
- // 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
- // 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 RdxPHIsToFix;
+
+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::copysign:
+ case Intrinsic::floor:
+ case Intrinsic::ceil:
+ case Intrinsic::trunc:
+ case Intrinsic::rint:
+ case Intrinsic::nearbyint:
+ case Intrinsic::round:
+ case Intrinsic::pow:
+ case Intrinsic::fma:
+ case Intrinsic::fmuladd:
+ case Intrinsic::lifetime_start:
+ case Intrinsic::lifetime_end:
+ 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 and it does
+ // not have local linkage.
+ if (!F || F->hasLocalLinkage() || !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 checkUnaryFloatSignature(*CI, Intrinsic::sin);
+ case LibFunc::cos:
+ case LibFunc::cosf:
+ case LibFunc::cosl:
+ return checkUnaryFloatSignature(*CI, Intrinsic::cos);
+ case LibFunc::exp:
+ case LibFunc::expf:
+ case LibFunc::expl:
+ return checkUnaryFloatSignature(*CI, Intrinsic::exp);
+ case LibFunc::exp2:
+ case LibFunc::exp2f:
+ case LibFunc::exp2l:
+ return checkUnaryFloatSignature(*CI, Intrinsic::exp2);
+ case LibFunc::log:
+ case LibFunc::logf:
+ case LibFunc::logl:
+ return checkUnaryFloatSignature(*CI, Intrinsic::log);
+ case LibFunc::log10:
+ case LibFunc::log10f:
+ case LibFunc::log10l:
+ return checkUnaryFloatSignature(*CI, Intrinsic::log10);
+ case LibFunc::log2:
+ case LibFunc::log2f:
+ case LibFunc::log2l:
+ return checkUnaryFloatSignature(*CI, Intrinsic::log2);
+ case LibFunc::fabs:
+ case LibFunc::fabsf:
+ case LibFunc::fabsl:
+ return checkUnaryFloatSignature(*CI, Intrinsic::fabs);
+ case LibFunc::copysign:
+ case LibFunc::copysignf:
+ case LibFunc::copysignl:
+ return checkBinaryFloatSignature(*CI, Intrinsic::copysign);
+ case LibFunc::floor:
+ case LibFunc::floorf:
+ case LibFunc::floorl:
+ return checkUnaryFloatSignature(*CI, Intrinsic::floor);
+ case LibFunc::ceil:
+ case LibFunc::ceilf:
+ case LibFunc::ceill:
+ return checkUnaryFloatSignature(*CI, Intrinsic::ceil);
+ case LibFunc::trunc:
+ case LibFunc::truncf:
+ case LibFunc::truncl:
+ return checkUnaryFloatSignature(*CI, Intrinsic::trunc);
+ case LibFunc::rint:
+ case LibFunc::rintf:
+ case LibFunc::rintl:
+ return checkUnaryFloatSignature(*CI, Intrinsic::rint);
+ case LibFunc::nearbyint:
+ case LibFunc::nearbyintf:
+ case LibFunc::nearbyintl:
+ return checkUnaryFloatSignature(*CI, Intrinsic::nearbyint);
+ case LibFunc::round:
+ case LibFunc::roundf:
+ case LibFunc::roundl:
+ return checkUnaryFloatSignature(*CI, Intrinsic::round);
+ case LibFunc::pow:
+ case LibFunc::powf:
+ case LibFunc::powl:
+ return checkBinaryFloatSignature(*CI, Intrinsic::pow);
+ }
+
+ return Intrinsic::not_intrinsic;
+}
+
+/// This function translates the reduction kind to an LLVM binary operator.
+static unsigned
+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;
+ case LoopVectorizationLegality::RK_IntegerMinMax:
+ return Instruction::ICmp;
+ case LoopVectorizationLegality::RK_FloatMinMax:
+ return Instruction::FCmp;
+ default:
+ llvm_unreachable("Unknown reduction operation");
+ }
+}
+
+Value *createMinMaxOp(IRBuilder<> &Builder,
+ LoopVectorizationLegality::MinMaxReductionKind RK,
+ Value *Left,
+ Value *Right) {
+ CmpInst::Predicate P = CmpInst::ICMP_NE;
+ switch (RK) {
+ default:
+ llvm_unreachable("Unknown min/max reduction kind");
+ case LoopVectorizationLegality::MRK_UIntMin:
+ P = CmpInst::ICMP_ULT;
+ break;
+ case LoopVectorizationLegality::MRK_UIntMax:
+ P = CmpInst::ICMP_UGT;
+ break;
+ case LoopVectorizationLegality::MRK_SIntMin:
+ P = CmpInst::ICMP_SLT;
+ break;
+ case LoopVectorizationLegality::MRK_SIntMax:
+ P = CmpInst::ICMP_SGT;
+ break;
+ case LoopVectorizationLegality::MRK_FloatMin:
+ P = CmpInst::FCMP_OLT;
+ break;
+ case LoopVectorizationLegality::MRK_FloatMax:
+ P = CmpInst::FCMP_OGT;
+ break;
+ }
+
+ Value *Cmp;
+ if (RK == LoopVectorizationLegality::MRK_FloatMin ||
+ RK == LoopVectorizationLegality::MRK_FloatMax)
+ Cmp = Builder.CreateFCmp(P, Left, Right, "rdx.minmax.cmp");
+ else
+ Cmp = Builder.CreateICmp(P, Left, Right, "rdx.minmax.cmp");
+
+ Value *Select = Builder.CreateSelect(Cmp, Left, Right, "rdx.minmax.select");
+ return Select;
+}
+
+namespace {
+struct CSEDenseMapInfo {
+ static bool canHandle(Instruction *I) {
+ return isa<InsertElementInst>(I) || isa<ExtractElementInst>(I) ||
+ isa<ShuffleVectorInst>(I) || isa<GetElementPtrInst>(I);
+ }
+ static inline Instruction *getEmptyKey() {
+ return DenseMapInfo<Instruction *>::getEmptyKey();
+ }
+ static inline Instruction *getTombstoneKey() {
+ return DenseMapInfo<Instruction *>::getTombstoneKey();
+ }
+ static unsigned getHashValue(Instruction *I) {
+ assert(canHandle(I) && "Unknown instruction!");
+ return hash_combine(I->getOpcode(), hash_combine_range(I->value_op_begin(),
+ I->value_op_end()));
+ }
+ static bool isEqual(Instruction *LHS, Instruction *RHS) {
+ if (LHS == getEmptyKey() || RHS == getEmptyKey() ||
+ LHS == getTombstoneKey() || RHS == getTombstoneKey())
+ return LHS == RHS;
+ return LHS->isIdenticalTo(RHS);
+ }
+};
+}
+
+///\brief Perform cse of induction variable instructions.
+static void cse(BasicBlock *BB) {
+ // Perform simple cse.
+ SmallDenseMap<Instruction *, Instruction *, 4, CSEDenseMapInfo> CSEMap;
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;) {
+ Instruction *In = I++;
+
+ if (!CSEDenseMapInfo::canHandle(In))
+ continue;
+
+ // Check if we can replace this instruction with any of the
+ // visited instructions.
+ if (Instruction *V = CSEMap.lookup(In)) {
+ In->replaceAllUsesWith(V);
+ In->eraseFromParent();
+ continue;
+ }
+
+ CSEMap[In] = In;
+ }
+}
+
+void
+InnerLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) {
+ //===------------------------------------------------===//
+ //
+ // Notice: any optimization or new instruction that go
+ // into the code below should be also be implemented in
+ // the cost-model.
+ //
+ //===------------------------------------------------===//
+ 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
+ // 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 RdxPHIsToFix;
// Scan the loop in a topological order to ensure that defs are vectorized
// before users.
LoopVectorizationLegality::ReductionDescriptor RdxDesc =
(*Legal->getReductionVars())[RdxPhi];
+ setDebugLocFromInst(Builder, RdxDesc.StartValue);
+
// 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.
VectorParts &VectorExit = getVectorValue(RdxDesc.LoopExitInstr);
// Find the reduction identity variable. Zero for addition, or, xor,
// one for multiplication, -1 for And.
- Constant *Identity = getUniformVector(getReductionIdentity(RdxDesc.Kind),
- VecTy->getScalarType());
+ Value *Identity;
+ Value *VectorStart;
+ if (RdxDesc.Kind == LoopVectorizationLegality::RK_IntegerMinMax ||
+ RdxDesc.Kind == LoopVectorizationLegality::RK_FloatMinMax) {
+ // MinMax reduction have the start value as their identify.
+ if (VF == 1) {
+ VectorStart = Identity = RdxDesc.StartValue;
+ } else {
+ VectorStart = Identity = Builder.CreateVectorSplat(VF,
+ RdxDesc.StartValue,
+ "minmax.ident");
+ }
+ } else {
+ // Handle other reduction kinds:
+ Constant *Iden =
+ LoopVectorizationLegality::getReductionIdentity(RdxDesc.Kind,
+ VecTy->getScalarType());
+ if (VF == 1) {
+ Identity = Iden;
+ // This vector is the Identity vector where the first element is the
+ // incoming scalar reduction.
+ VectorStart = RdxDesc.StartValue;
+ } else {
+ 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);
+ // This vector is the Identity vector where the first element is the
+ // incoming scalar reduction.
+ VectorStart = Builder.CreateInsertElement(Identity,
+ RdxDesc.StartValue, Zero);
+ }
+ }
// Fix the vector-loop phi.
// We created the induction variable so we know that the
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
+ // 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);
Builder.SetInsertPoint(LoopMiddleBlock->getFirstInsertionPt());
VectorParts RdxParts;
+ setDebugLocFromInst(Builder, RdxDesc.LoopExitInstr);
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;
- NewPhi->addIncoming(StartVal, LoopBypassBlock);
+ 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];
+ unsigned Op = getReductionBinOp(RdxDesc.Kind);
+ setDebugLocFromInst(Builder, ReducedPartRdx);
for (unsigned part = 1; part < UF; ++part) {
- switch (RdxDesc.Kind) {
- case LoopVectorizationLegality::IntegerAdd:
- ReducedPartRdx =
- Builder.CreateAdd(RdxParts[part], ReducedPartRdx, "add.rdx");
- break;
- case LoopVectorizationLegality::IntegerMult:
- ReducedPartRdx =
- Builder.CreateMul(RdxParts[part], ReducedPartRdx, "mul.rdx");
- break;
- case LoopVectorizationLegality::IntegerOr:
- ReducedPartRdx =
- Builder.CreateOr(RdxParts[part], ReducedPartRdx, "or.rdx");
- break;
- case LoopVectorizationLegality::IntegerAnd:
- ReducedPartRdx =
- Builder.CreateAnd(RdxParts[part], ReducedPartRdx, "and.rdx");
- break;
- case LoopVectorizationLegality::IntegerXor:
- ReducedPartRdx =
- Builder.CreateXor(RdxParts[part], ReducedPartRdx, "xor.rdx");
- break;
- default:
- llvm_unreachable("Unknown reduction operation");
- }
+ if (Op != Instruction::ICmp && Op != Instruction::FCmp)
+ ReducedPartRdx = Builder.CreateBinOp((Instruction::BinaryOps)Op,
+ RdxParts[part], ReducedPartRdx,
+ "bin.rdx");
+ else
+ ReducedPartRdx = createMinMaxOp(Builder, RdxDesc.MinMaxKind,
+ ReducedPartRdx, RdxParts[part]);
}
-
-
- // 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 =
+
+ if (VF > 1) {
+ // 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");
- // Emit the operation on the shuffled value.
- switch (RdxDesc.Kind) {
- case LoopVectorizationLegality::IntegerAdd:
- TmpVec = Builder.CreateAdd(TmpVec, Shuf, "add.rdx");
- break;
- case LoopVectorizationLegality::IntegerMult:
- TmpVec = Builder.CreateMul(TmpVec, Shuf, "mul.rdx");
- break;
- case LoopVectorizationLegality::IntegerOr:
- TmpVec = Builder.CreateOr(TmpVec, Shuf, "or.rdx");
- break;
- case LoopVectorizationLegality::IntegerAnd:
- TmpVec = Builder.CreateAnd(TmpVec, Shuf, "and.rdx");
- break;
- case LoopVectorizationLegality::IntegerXor:
- TmpVec = Builder.CreateXor(TmpVec, Shuf, "xor.rdx");
- break;
- default:
- llvm_unreachable("Unknown reduction operation");
+ if (Op != Instruction::ICmp && Op != Instruction::FCmp)
+ TmpVec = Builder.CreateBinOp((Instruction::BinaryOps)Op, TmpVec, Shuf,
+ "bin.rdx");
+ else
+ TmpVec = createMinMaxOp(Builder, RdxDesc.MinMaxKind, TmpVec, Shuf);
}
- }
- // The result is in the first element of the vector.
- Value *Scalar0 = Builder.CreateExtractElement(TmpVec, Builder.getInt32(0));
+ // The result is in the first element of the vector.
+ ReducedPartRdx = 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.
for (BasicBlock::iterator LEI = LoopExitBlock->begin(),
LEE = LoopExitBlock->end(); LEI != LEE; ++LEI) {
PHINode *LCSSAPhi = dyn_cast<PHINode>(LEI);
- if (!LCSSAPhi) continue;
+ if (!LCSSAPhi) break;
// All PHINodes need to have a single entry edge, or two if
// we already fixed them.
// incoming bypass edge.
if (LCSSAPhi->getIncomingValue(0) == RdxDesc.LoopExitInstr) {
// Add an edge coming from the bypass.
- LCSSAPhi->addIncoming(Scalar0, LoopMiddleBlock);
+ LCSSAPhi->addIncoming(ReducedPartRdx, LoopMiddleBlock);
break;
}
}// end of the LCSSA phi scan.
assert(IncomingEdgeBlockIdx >= 0 && "Invalid block index");
// Pick the other block.
int SelfEdgeBlockIdx = (IncomingEdgeBlockIdx ? 0 : 1);
- (RdxPhi)->setIncomingValue(SelfEdgeBlockIdx, Scalar0);
+ (RdxPhi)->setIncomingValue(SelfEdgeBlockIdx, ReducedPartRdx);
(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.
+ fixLCSSAPHIs();
+
+ // Remove redundant induction instructions.
+ cse(LoopVectorBody);
+}
+
+void InnerLoopVectorizer::fixLCSSAPHIs() {
for (BasicBlock::iterator LEI = LoopExitBlock->begin(),
LEE = LoopExitBlock->end(); LEI != LEE; ++LEI) {
PHINode *LCSSAPhi = dyn_cast<PHINode>(LEI);
- if (!LCSSAPhi) continue;
+ if (!LCSSAPhi) break;
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");
+ // Look for cached value.
+ std::pair<BasicBlock*, BasicBlock*> Edge(Src, Dst);
+ EdgeMaskCache::iterator ECEntryIt = MaskCache.find(Edge);
+ if (ECEntryIt != MaskCache.end())
+ return ECEntryIt->second;
+
VectorParts SrcMask = createBlockInMask(Src);
// The terminator has to be a branch inst!
for (unsigned part = 0; part < UF; ++part)
EdgeMask[part] = Builder.CreateAnd(EdgeMask[part], SrcMask[part]);
+
+ MaskCache[Edge] = EdgeMask;
return EdgeMask;
}
+ MaskCache[Edge] = SrcMask;
return SrcMask;
}
return BlockMask;
}
-void
-InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
- BasicBlock *BB, PhiVector *PV) {
- Constant *Zero = Builder.getInt32(0);
-
- // 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;
- }
+void InnerLoopVectorizer::widenPHIInstruction(Instruction *PN,
+ InnerLoopVectorizer::VectorParts &Entry,
+ LoopVectorizationLegality *Legal,
+ unsigned UF, unsigned VF, PhiVector *PV) {
+ PHINode* P = cast<PHINode>(PN);
+ // Handle reduction variables:
+ if (Legal->getReductionVars()->count(P)) {
+ for (unsigned part = 0; part < UF; ++part) {
+ // This is phase one of vectorizing PHIs.
+ Type *VecTy = (VF == 1) ? PN->getType() :
+ VectorType::get(PN->getType(), VF);
+ Entry[part] = PHINode::Create(VecTy, 2, "vec.phi",
+ LoopVectorBody-> getFirstInsertionPt());
+ }
+ PV->push_back(P);
+ return;
+ }
- // 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;
+ setDebugLocFromInst(Builder, P);
+ // 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.
+
+ unsigned NumIncoming = P->getNumIncomingValues();
+
+ // Generate a sequence of selects of the form:
+ // SELECT(Mask3, In3,
+ // SELECT(Mask2, In2,
+ // ( ...)))
+ for (unsigned In = 0; In < NumIncoming; In++) {
+ VectorParts Cond = createEdgeMask(P->getIncomingBlock(In),
+ P->getParent());
+ VectorParts &In0 = getVectorValue(P->getIncomingValue(In));
+
+ for (unsigned part = 0; part < UF; ++part) {
+ // We might have single edge PHIs (blocks) - use an identity
+ // 'select' for the first PHI operand.
+ if (In == 0)
+ Entry[part] = Builder.CreateSelect(Cond[part], In0[part],
+ In0[part]);
+ else
+ // Select between the current value and the previous incoming edge
+ // based on the incoming mask.
+ Entry[part] = Builder.CreateSelect(Cond[part], In0[part],
+ Entry[part], "predphi");
}
+ }
+ return;
+ }
- // This PHINode must be an induction variable.
- // Make sure that we know about it.
- assert(Legal->getInductionVars()->count(P) &&
- "Not an induction variable");
+ // 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);
+ LoopVectorizationLegality::InductionInfo II =
+ Legal->getInductionVars()->lookup(P);
- switch (II.IK) {
- case LoopVectorizationLegality::NoInduction:
- llvm_unreachable("Unknown induction");
- case LoopVectorizationLegality::IntInduction: {
- assert(P == OldInduction && "Unexpected PHI");
- Value *Broadcasted = getBroadcastInstrs(Induction);
+ switch (II.IK) {
+ case LoopVectorizationLegality::IK_NoInduction:
+ llvm_unreachable("Unknown induction");
+ case LoopVectorizationLegality::IK_IntInduction: {
+ assert(P->getType() == II.StartValue->getType() && "Types must match");
+ Type *PhiTy = P->getType();
+ Value *Broadcasted;
+ if (P == OldInduction) {
+ // Handle the canonical induction variable. We might have had to
+ // extend the type.
+ Broadcasted = Builder.CreateTrunc(Induction, PhiTy);
+ } else {
+ // Handle other induction variables that are now based on the
+ // canonical one.
+ Value *NormalizedIdx = Builder.CreateSub(Induction, ExtendedIdx,
+ "normalized.idx");
+ NormalizedIdx = Builder.CreateSExtOrTrunc(NormalizedIdx, PhiTy);
+ Broadcasted = Builder.CreateAdd(II.StartValue, NormalizedIdx,
+ "offset.idx");
+ }
+ Broadcasted = getBroadcastInstrs(Broadcasted);
+ // After broadcasting the induction variable we need to make the vector
+ // consecutive by adding 0, 1, 2, etc.
+ for (unsigned part = 0; part < UF; ++part)
+ Entry[part] = getConsecutiveVector(Broadcasted, VF * part, false);
+ return;
+ }
+ case LoopVectorizationLegality::IK_ReverseIntInduction:
+ case LoopVectorizationLegality::IK_PtrInduction:
+ case LoopVectorizationLegality::IK_ReversePtrInduction:
+ // Handle reverse integer and pointer inductions.
+ Value *StartIdx = ExtendedIdx;
+ // 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 0, 1, 2 ...
+ // vector consecutive by adding ... -3, -2, -1, 0.
for (unsigned part = 0; part < UF; ++part)
- Entry[part] = getConsecutiveVector(Broadcasted, VF * part, false);
- continue;
+ Entry[part] = getConsecutiveVector(Broadcasted, -(int)VF * part,
+ true);
+ return;
}
- case LoopVectorizationLegality::ReverseIntInduction:
- case LoopVectorizationLegality::PtrInduction:
- // 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::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);
+ // 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) {
+ if (VF == 1) {
+ int EltIndex = (part) * (Reverse ? -1 : 1);
+ Constant *Idx = ConstantInt::get(Induction->getType(), EltIndex);
+ Value *GlobalIdx;
+ if (Reverse)
+ GlobalIdx = Builder.CreateSub(Idx, NormalizedIdx, "gep.ridx");
+ else
+ GlobalIdx = Builder.CreateAdd(NormalizedIdx, Idx, "gep.idx");
+
+ Value *SclrGep = Builder.CreateGEP(II.StartValue, GlobalIdx,
+ "next.gep");
+ Entry[part] = SclrGep;
continue;
}
- // Handle the pointer induction variable case.
- assert(P->getType()->isPointerTy() && "Unexpected type.");
-
- // 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) {
- Constant *Idx = ConstantInt::get(Induction->getType(),
- i + part * VF);
- Value *GlobalIdx = Builder.CreateAdd(NormalizedIdx, Idx,
- "gep.idx");
- Value *SclrGep = Builder.CreateGEP(II.StartValue, GlobalIdx,
- "next.gep");
- VecVal = Builder.CreateInsertElement(VecVal, SclrGep,
- Builder.getInt32(i),
- "insert.gep");
- }
- Entry[part] = VecVal;
+ 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");
}
- continue;
+ Entry[part] = VecVal;
}
+ return;
+ }
+}
+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:{
+ // Vectorize PHINodes.
+ widenPHIInstruction(it, Entry, Legal, UF, VF, PV);
+ continue;
}// End of PHI.
case Instruction::Add:
case Instruction::Xor: {
// Just widen binops.
BinaryOperator *BinOp = dyn_cast<BinaryOperator>(it);
+ setDebugLocFromInst(Builder, BinOp);
VectorParts &A = getVectorValue(it->getOperand(0));
VectorParts &B = getVectorValue(it->getOperand(1));
for (unsigned Part = 0; Part < UF; ++Part) {
Value *V = Builder.CreateBinOp(BinOp->getOpcode(), A[Part], B[Part]);
- // Update the NSW, NUW and Exact flags.
- BinaryOperator *VecOp = cast<BinaryOperator>(V);
- if (isa<OverflowingBinaryOperator>(BinOp)) {
+ // 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 (isa<PossiblyExactOperator>(VecOp))
+ if (
VecOp && isa<PossiblyExactOperator>(VecOp))
VecOp->setIsExact(BinOp->isExact());
Entry[Part] = V;
// instruction with a scalar condition. Otherwise, use vector-select.
bool InvariantCond = SE->isLoopInvariant(SE->getSCEV(it->getOperand(0)),
OrigLoop);
+ setDebugLocFromInst(Builder, it);
// The condition can be loop invariant but still defined inside the
// loop. This means that we can't just use the original 'cond' value.
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));
+
+ Value *ScalarCond = (VF == 1) ? Cond[0] :
+ Builder.CreateExtractElement(Cond[0], Builder.getInt32(0));
+
for (unsigned Part = 0; Part < UF; ++Part) {
Entry[Part] = Builder.CreateSelect(
InvariantCond ? ScalarCond : Cond[Part],
// Widen compares. Generate vector compares.
bool FCmp = (it->getOpcode() == Instruction::FCmp);
CmpInst *Cmp = dyn_cast<CmpInst>(it);
+ setDebugLocFromInst(Builder, it);
VectorParts &A = getVectorValue(it->getOperand(0));
VectorParts &B = getVectorValue(it->getOperand(1));
for (unsigned Part = 0; Part < UF; ++Part) {
break;
}
- case Instruction::Store: {
- // Attempt to issue a wide store.
- StoreInst *SI = dyn_cast<StoreInst>(it);
- 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");
-
-
- int Stride = Legal->isConsecutivePtr(Ptr);
- bool Reverse = Stride < 0;
- if (Stride == 0) {
- scalarizeInstruction(it);
+ case Instruction::Store:
+ case Instruction::Load:
+ vectorizeMemoryInstruction(it, Legal);
break;
- }
-
- // Handle consecutive stores.
-
- GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
- if (Gep) {
- // 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);
- 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);
- }
-
- 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, StTy->getPointerTo());
- Builder.CreateStore(StoredVal[Part], VecPtr)->setAlignment(Alignment);
- }
- break;
- }
- case Instruction::Load: {
- // Attempt to issue a wide load.
- LoadInst *LI = dyn_cast<LoadInst>(it);
- Type *RetTy = VectorType::get(LI->getType(), VF);
- Value *Ptr = LI->getPointerOperand();
- unsigned Alignment = LI->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;
- if (Legal->isUniform(Ptr) || Stride == 0) {
- scalarizeInstruction(it);
- break;
- }
-
- GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
- if (Gep) {
- // 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);
- 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);
- }
-
- 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, RetTy->getPointerTo());
- Value *LI = Builder.CreateLoad(VecPtr, "wide.load");
- cast<LoadInst>(LI)->setAlignment(Alignment);
- Entry[Part] = Reverse ? reverseVector(LI) : LI;
- }
- break;
- }
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPToUI:
case Instruction::FPTrunc:
case Instruction::BitCast: {
CastInst *CI = dyn_cast<CastInst>(it);
+ setDebugLocFromInst(Builder, 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,
break;
}
/// Vectorize casts.
- Type *DestTy = VectorType::get(CI->getType()->getScalarType(), VF);
+ Type *DestTy = (VF == 1) ? CI->getType() :
+ VectorType::get(CI->getType(), VF);
VectorParts &A = getVectorValue(it->getOperand(0));
for (unsigned Part = 0; Part < UF; ++Part)
}
case Instruction::Call: {
- assert(isTriviallyVectorizableIntrinsic(it));
+ // Ignore dbg intrinsics.
+ if (isa<DbgInfoIntrinsic>(it))
+ break;
+ setDebugLocFromInst(Builder, it);
+
Module *M = BB->getParent()->getParent();
- IntrinsicInst *II = cast<IntrinsicInst>(it);
- Intrinsic::ID ID = II->getIntrinsicID();
- for (unsigned Part = 0; Part < UF; ++Part) {
- SmallVector<Value*, 4> Args;
- for (unsigned i = 0, ie = II->getNumArgOperands(); i != ie; ++i) {
- VectorParts &Arg = getVectorValue(II->getArgOperand(i));
- Args.push_back(Arg[Part]);
+ CallInst *CI = cast<CallInst>(it);
+ Intrinsic::ID ID = getIntrinsicIDForCall(CI, TLI);
+ assert(ID && "Not an intrinsic call!");
+ switch (ID) {
+ case Intrinsic::lifetime_end:
+ case Intrinsic::lifetime_start:
+ scalarizeInstruction(it);
+ break;
+ default:
+ 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[] = {CI->getType()};
+ if (VF > 1)
+ Tys[0] = VectorType::get(CI->getType()->getScalarType(), VF);
+
+ Function *F = Intrinsic::getDeclaration(M, ID, Tys);
+ Entry[Part] = Builder.CreateCall(F, Args);
}
- Type *Tys[] = { VectorType::get(II->getType()->getScalarType(), VF) };
- Function *F = Intrinsic::getDeclaration(M, ID, Tys);
- Entry[Part] = Builder.CreateCall(F, Args);
+ break;
}
break;
}
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);
return false;
assert(TheLoop->getNumBlocks() > 1 && "Single block loops are vectorizable");
- std::vector<BasicBlock*> &LoopBlocks = TheLoop->getBlocksVector();
+
+ // A list of pointers that we can safely read and write to.
+ SmallPtrSet<Value *, 8> SafePointes;
+
+ // Collect safe addresses.
+ for (Loop::block_iterator BI = TheLoop->block_begin(),
+ BE = TheLoop->block_end(); BI != BE; ++BI) {
+ BasicBlock *BB = *BI;
+
+ if (blockNeedsPredication(BB))
+ continue;
+
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
+ if (LoadInst *LI = dyn_cast<LoadInst>(I))
+ SafePointes.insert(LI->getPointerOperand());
+ else if (StoreInst *SI = dyn_cast<StoreInst>(I))
+ SafePointes.insert(SI->getPointerOperand());
+ }
+ }
// Collect the blocks that need predication.
- for (unsigned i = 0, e = LoopBlocks.size(); i < e; ++i) {
- BasicBlock *BB = LoopBlocks[i];
+ for (Loop::block_iterator BI = TheLoop->block_begin(),
+ BE = TheLoop->block_end(); BI != BE; ++BI) {
+ BasicBlock *BB = *BI;
// 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))
+ if (blockNeedsPredication(BB) && !blockCanBePredicated(BB, SafePointes))
return false;
}
}
bool LoopVectorizationLegality::canVectorize() {
- assert(TheLoop->getLoopPreheader() && "No preheader!!");
+ // We must have a loop in canonical form. Loops with indirectbr in them cannot
+ // be canonicalized.
+ if (!TheLoop->getLoopPreheader())
+ return false;
// We can only vectorize innermost loops.
if (TheLoop->getSubLoopsVector().size())
if (!TheLoop->getExitingBlock())
return false;
- unsigned NumBlocks = TheLoop->getNumBlocks();
+ // We need to have a loop header.
+ DEBUG(dbgs() << "LV: Found a loop: " <<
+ TheLoop->getHeader()->getName() << '\n');
- // Check if we can if-convert non single-bb loops.
+ // Check if we can if-convert non-single-bb loops.
+ unsigned NumBlocks = TheLoop->getNumBlocks();
if (NumBlocks != 1 && !canVectorizeWithIfConvert()) {
DEBUG(dbgs() << "LV: Can't if-convert the loop.\n");
return false;
}
- // We need to have a loop header.
- 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, Latch);
+ const SCEV *ExitCount = SE->getBackedgeTakenCount(TheLoop);
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.
+ BasicBlock *Latch = TheLoop->getLoopLatch();
unsigned TC = SE->getSmallConstantTripCount(TheLoop, Latch);
- if (TC > 0u && TC < TinyTripCountThreshold) {
+ 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;
return true;
}
+static Type *convertPointerToIntegerType(DataLayout &DL, Type *Ty) {
+ if (Ty->isPointerTy())
+ return DL.getIntPtrType(Ty);
+
+ // It is possible that char's or short's overflow when we ask for the loop's
+ // trip count, work around this by changing the type size.
+ if (Ty->getScalarSizeInBits() < 32)
+ return Type::getInt32Ty(Ty->getContext());
+
+ return Ty;
+}
+
+static Type* getWiderType(DataLayout &DL, Type *Ty0, Type *Ty1) {
+ Ty0 = convertPointerToIntegerType(DL, Ty0);
+ Ty1 = convertPointerToIntegerType(DL, Ty1);
+ if (Ty0->getScalarSizeInBits() > Ty1->getScalarSizeInBits())
+ return Ty0;
+ return Ty1;
+}
+
+/// \brief Check that the instruction has outside loop users and is not an
+/// identified reduction variable.
+static bool hasOutsideLoopUser(const Loop *TheLoop, Instruction *Inst,
+ SmallPtrSet<Value *, 4> &Reductions) {
+ // Reduction instructions are allowed to have exit users. All other
+ // instructions must not have external users.
+ if (!Reductions.count(Inst))
+ //Check that all of the users of the loop are inside the BB.
+ for (Value::use_iterator I = Inst->use_begin(), E = Inst->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 true;
+ }
+ }
+ return false;
+}
+
bool LoopVectorizationLegality::canVectorizeInstrs() {
BasicBlock *PreHeader = TheLoop->getLoopPreheader();
BasicBlock *Header = TheLoop->getHeader();
+ // Look for the attribute signaling the absence of NaNs.
+ Function &F = *Header->getParent();
+ if (F.hasFnAttribute("no-nans-fp-math"))
+ HasFunNoNaNAttr = F.getAttributes().getAttribute(
+ AttributeSet::FunctionIndex,
+ "no-nans-fp-math").getValueAsString() == "true";
+
// For each block in the loop.
for (Loop::block_iterator bb = TheLoop->block_begin(),
be = TheLoop->block_end(); bb != be; ++bb) {
++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;
- }
-
+ Type *PhiTy = Phi->getType();
// Check that this PHI type is allowed.
- if (!Phi->getType()->isIntegerTy() &&
- !Phi->getType()->isPointerTy()) {
+ if (!PhiTy->isIntegerTy() &&
+ !PhiTy->isFloatingPointTy() &&
+ !PhiTy->isPointerTy()) {
DEBUG(dbgs() << "LV: Found an non-int non-pointer PHI.\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;
+ if (*bb != Header) {
+ // Check that this instruction has no outside users or is an
+ // identified reduction value with an outside user.
+ if(!hasOutsideLoopUser(TheLoop, it, AllowedExit))
+ continue;
+ return false;
+ }
+
+ // We only allow if-converted PHIs with more than two incoming values.
+ if (Phi->getNumIncomingValues() != 2) {
+ DEBUG(dbgs() << "LV: Found an invalid PHI.\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 (NoInduction != IK) {
+ if (IK_NoInduction != IK) {
+ // Get the widest type.
+ if (!WidestIndTy)
+ WidestIndTy = convertPointerToIntegerType(*DL, PhiTy);
+ else
+ WidestIndTy = getWiderType(*DL, PhiTy, WidestIndTy);
+
// Int inductions are special because we only allow one IV.
- if (IK == IntInduction) {
- if (Induction) {
- DEBUG(dbgs() << "LV: Found too many inductions."<< *Phi <<"\n");
- return false;
- }
- Induction = Phi;
+ if (IK == IK_IntInduction) {
+ // Use the phi node with the widest type as induction. Use the last
+ // one if there are multiple (no good reason for doing this other
+ // than it is expedient).
+ if (!Induction || PhiTy == WidestIndTy)
+ Induction = Phi;
}
DEBUG(dbgs() << "LV: Found an induction variable.\n");
Inductions[Phi] = InductionInfo(StartValue, IK);
+
+ // Until we explicitly handle the case of an induction variable with
+ // an outside loop user we have to give up vectorizing this loop.
+ if (hasOutsideLoopUser(TheLoop, it, AllowedExit))
+ return false;
+
continue;
}
- if (AddReductionVar(Phi, IntegerAdd)) {
+ if (AddReductionVar(Phi, RK_IntegerAdd)) {
DEBUG(dbgs() << "LV: Found an ADD reduction PHI."<< *Phi <<"\n");
continue;
}
- if (AddReductionVar(Phi, IntegerMult)) {
+ if (AddReductionVar(Phi, RK_IntegerMult)) {
DEBUG(dbgs() << "LV: Found a MUL reduction PHI."<< *Phi <<"\n");
continue;
}
- if (AddReductionVar(Phi, IntegerOr)) {
+ if (AddReductionVar(Phi, RK_IntegerOr)) {
DEBUG(dbgs() << "LV: Found an OR reduction PHI."<< *Phi <<"\n");
continue;
}
- if (AddReductionVar(Phi, IntegerAnd)) {
+ if (AddReductionVar(Phi, RK_IntegerAnd)) {
DEBUG(dbgs() << "LV: Found an AND reduction PHI."<< *Phi <<"\n");
continue;
}
- if (AddReductionVar(Phi, IntegerXor)) {
+ if (AddReductionVar(Phi, RK_IntegerXor)) {
DEBUG(dbgs() << "LV: Found a XOR reduction PHI."<< *Phi <<"\n");
continue;
}
+ if (AddReductionVar(Phi, RK_IntegerMinMax)) {
+ DEBUG(dbgs() << "LV: Found a MINMAX 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;
+ }
+ if (AddReductionVar(Phi, RK_FloatMinMax)) {
+ DEBUG(dbgs() << "LV: Found an float MINMAX 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.
+ // 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 && !isTriviallyVectorizableIntrinsic(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");
+ // Also, we can't vectorize extractelement instructions.
+ if ((!VectorType::isValidElementType(it->getType()) &&
+ !it->getType()->isVoidTy()) || isa<ExtractElementInst>(it)) {
+ DEBUG(dbgs() << "LV: Found unvectorizable type.\n");
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;
- }
- }
+ if (hasOutsideLoopUser(TheLoop, it, AllowedExit))
+ return false;
+
} // next instr.
}
if (!Induction) {
DEBUG(dbgs() << "LV: Did not find one integer induction var.\n");
- assert(getInductionVars()->size() && "No induction variables");
+ if (Inductions.empty())
+ return false;
}
return true;
Uniforms.insert(I);
// Insert all operands.
- for (int i = 0, Op = I->getNumOperands(); i < Op; ++i) {
- Worklist.push_back(I->getOperand(i));
+ Worklist.insert(Worklist.end(), I->op_begin(), I->op_end());
+ }
+}
+
+namespace {
+/// \brief Analyses memory accesses in a loop.
+///
+/// Checks whether run time pointer checks are needed and builds sets for data
+/// dependence checking.
+class AccessAnalysis {
+public:
+ /// \brief Read or write access location.
+ typedef PointerIntPair<Value *, 1, bool> MemAccessInfo;
+ typedef SmallPtrSet<MemAccessInfo, 8> MemAccessInfoSet;
+
+ /// \brief Set of potential dependent memory accesses.
+ typedef EquivalenceClasses<MemAccessInfo> DepCandidates;
+
+ AccessAnalysis(DataLayout *Dl, DepCandidates &DA) :
+ DL(Dl), DepCands(DA), AreAllWritesIdentified(true),
+ AreAllReadsIdentified(true), IsRTCheckNeeded(false) {}
+
+ /// \brief Register a load and whether it is only read from.
+ void addLoad(Value *Ptr, bool IsReadOnly) {
+ Accesses.insert(MemAccessInfo(Ptr, false));
+ if (IsReadOnly)
+ ReadOnlyPtr.insert(Ptr);
+ }
+
+ /// \brief Register a store.
+ void addStore(Value *Ptr) {
+ Accesses.insert(MemAccessInfo(Ptr, true));
+ }
+
+ /// \brief Check whether we can check the pointers at runtime for
+ /// non-intersection.
+ bool canCheckPtrAtRT(LoopVectorizationLegality::RuntimePointerCheck &RtCheck,
+ unsigned &NumComparisons, ScalarEvolution *SE,
+ Loop *TheLoop, bool ShouldCheckStride = false);
+
+ /// \brief Goes over all memory accesses, checks whether a RT check is needed
+ /// and builds sets of dependent accesses.
+ void buildDependenceSets() {
+ // Process read-write pointers first.
+ processMemAccesses(false);
+ // Next, process read pointers.
+ processMemAccesses(true);
+ }
+
+ bool isRTCheckNeeded() { return IsRTCheckNeeded; }
+
+ bool isDependencyCheckNeeded() { return !CheckDeps.empty(); }
+ void resetDepChecks() { CheckDeps.clear(); }
+
+ MemAccessInfoSet &getDependenciesToCheck() { return CheckDeps; }
+
+private:
+ typedef SetVector<MemAccessInfo> PtrAccessSet;
+ typedef DenseMap<Value*, MemAccessInfo> UnderlyingObjToAccessMap;
+
+ /// \brief Go over all memory access or only the deferred ones if
+ /// \p UseDeferred is true and check whether runtime pointer checks are needed
+ /// and build sets of dependency check candidates.
+ void processMemAccesses(bool UseDeferred);
+
+ /// Set of all accesses.
+ PtrAccessSet Accesses;
+
+ /// Set of access to check after all writes have been processed.
+ PtrAccessSet DeferredAccesses;
+
+ /// Map of pointers to last access encountered.
+ UnderlyingObjToAccessMap ObjToLastAccess;
+
+ /// Set of accesses that need a further dependence check.
+ MemAccessInfoSet CheckDeps;
+
+ /// Set of pointers that are read only.
+ SmallPtrSet<Value*, 16> ReadOnlyPtr;
+
+ /// Set of underlying objects already written to.
+ SmallPtrSet<Value*, 16> WriteObjects;
+
+ DataLayout *DL;
+
+ /// Sets of potentially dependent accesses - members of one set share an
+ /// underlying pointer. The set "CheckDeps" identfies which sets really need a
+ /// dependence check.
+ DepCandidates &DepCands;
+
+ bool AreAllWritesIdentified;
+ bool AreAllReadsIdentified;
+ bool IsRTCheckNeeded;
+};
+
+} // end anonymous namespace
+
+/// \brief Check whether a pointer can participate in a runtime bounds check.
+static bool hasComputableBounds(ScalarEvolution *SE, Value *Ptr) {
+ const SCEV *PtrScev = SE->getSCEV(Ptr);
+ const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PtrScev);
+ if (!AR)
+ return false;
+
+ return AR->isAffine();
+}
+
+/// \brief Check the stride of the pointer and ensure that it does not wrap in
+/// the address space.
+static int isStridedPtr(ScalarEvolution *SE, DataLayout *DL, Value *Ptr,
+ const Loop *Lp);
+
+bool AccessAnalysis::canCheckPtrAtRT(
+ LoopVectorizationLegality::RuntimePointerCheck &RtCheck,
+ unsigned &NumComparisons, ScalarEvolution *SE,
+ Loop *TheLoop, bool ShouldCheckStride) {
+ // Find pointers with computable bounds. We are going to use this information
+ // to place a runtime bound check.
+ unsigned NumReadPtrChecks = 0;
+ unsigned NumWritePtrChecks = 0;
+ bool CanDoRT = true;
+
+ bool IsDepCheckNeeded = isDependencyCheckNeeded();
+ // We assign consecutive id to access from different dependence sets.
+ // Accesses within the same set don't need a runtime check.
+ unsigned RunningDepId = 1;
+ DenseMap<Value *, unsigned> DepSetId;
+
+ for (PtrAccessSet::iterator AI = Accesses.begin(), AE = Accesses.end();
+ AI != AE; ++AI) {
+ const MemAccessInfo &Access = *AI;
+ Value *Ptr = Access.getPointer();
+ bool IsWrite = Access.getInt();
+
+ // Just add write checks if we have both.
+ if (!IsWrite && Accesses.count(MemAccessInfo(Ptr, true)))
+ continue;
+
+ if (IsWrite)
+ ++NumWritePtrChecks;
+ else
+ ++NumReadPtrChecks;
+
+ if (hasComputableBounds(SE, Ptr) &&
+ // When we run after a failing dependency check we have to make sure we
+ // don't have wrapping pointers.
+ (!ShouldCheckStride || isStridedPtr(SE, DL, Ptr, TheLoop) == 1)) {
+ // The id of the dependence set.
+ unsigned DepId;
+
+ if (IsDepCheckNeeded) {
+ Value *Leader = DepCands.getLeaderValue(Access).getPointer();
+ unsigned &LeaderId = DepSetId[Leader];
+ if (!LeaderId)
+ LeaderId = RunningDepId++;
+ DepId = LeaderId;
+ } else
+ // Each access has its own dependence set.
+ DepId = RunningDepId++;
+
+ RtCheck.insert(SE, TheLoop, Ptr, IsWrite, DepId);
+
+ DEBUG(dbgs() << "LV: Found a runtime check ptr:" << *Ptr << '\n');
+ } else {
+ CanDoRT = false;
+ }
+ }
+
+ if (IsDepCheckNeeded && CanDoRT && RunningDepId == 2)
+ NumComparisons = 0; // Only one dependence set.
+ else {
+ NumComparisons = (NumWritePtrChecks * (NumReadPtrChecks +
+ NumWritePtrChecks - 1));
+ }
+
+ // If the pointers that we would use for the bounds comparison have different
+ // address spaces, assume the values aren't directly comparable, so we can't
+ // use them for the runtime check. We also have to assume they could
+ // overlap. In the future there should be metadata for whether address spaces
+ // are disjoint.
+ unsigned NumPointers = RtCheck.Pointers.size();
+ for (unsigned i = 0; i < NumPointers; ++i) {
+ for (unsigned j = i + 1; j < NumPointers; ++j) {
+ // Only need to check pointers between two different dependency sets.
+ if (RtCheck.DependencySetId[i] == RtCheck.DependencySetId[j])
+ continue;
+
+ Value *PtrI = RtCheck.Pointers[i];
+ Value *PtrJ = RtCheck.Pointers[j];
+
+ unsigned ASi = PtrI->getType()->getPointerAddressSpace();
+ unsigned ASj = PtrJ->getType()->getPointerAddressSpace();
+ if (ASi != ASj) {
+ DEBUG(dbgs() << "LV: Runtime check would require comparison between"
+ " different address spaces\n");
+ return false;
+ }
+ }
+ }
+
+ return CanDoRT;
+}
+
+static bool isFunctionScopeIdentifiedObject(Value *Ptr) {
+ return isNoAliasArgument(Ptr) || isNoAliasCall(Ptr) || isa<AllocaInst>(Ptr);
+}
+
+void AccessAnalysis::processMemAccesses(bool UseDeferred) {
+ // We process the set twice: first we process read-write pointers, last we
+ // process read-only pointers. This allows us to skip dependence tests for
+ // read-only pointers.
+
+ PtrAccessSet &S = UseDeferred ? DeferredAccesses : Accesses;
+ for (PtrAccessSet::iterator AI = S.begin(), AE = S.end(); AI != AE; ++AI) {
+ const MemAccessInfo &Access = *AI;
+ Value *Ptr = Access.getPointer();
+ bool IsWrite = Access.getInt();
+
+ DepCands.insert(Access);
+
+ // Memorize read-only pointers for later processing and skip them in the
+ // first round (they need to be checked after we have seen all write
+ // pointers). Note: we also mark pointer that are not consecutive as
+ // "read-only" pointers (so that we check "a[b[i]] +="). Hence, we need the
+ // second check for "!IsWrite".
+ bool IsReadOnlyPtr = ReadOnlyPtr.count(Ptr) && !IsWrite;
+ if (!UseDeferred && IsReadOnlyPtr) {
+ DeferredAccesses.insert(Access);
+ continue;
+ }
+
+ bool NeedDepCheck = false;
+ // Check whether there is the possiblity of dependency because of underlying
+ // objects being the same.
+ typedef SmallVector<Value*, 16> ValueVector;
+ ValueVector TempObjects;
+ GetUnderlyingObjects(Ptr, TempObjects, DL);
+ for (ValueVector::iterator UI = TempObjects.begin(), UE = TempObjects.end();
+ UI != UE; ++UI) {
+ Value *UnderlyingObj = *UI;
+
+ // If this is a write then it needs to be an identified object. If this a
+ // read and all writes (so far) are identified function scope objects we
+ // don't need an identified underlying object but only an Argument (the
+ // next write is going to invalidate this assumption if it is
+ // unidentified).
+ // This is a micro-optimization for the case where all writes are
+ // identified and we have one argument pointer.
+ // Otherwise, we do need a runtime check.
+ if ((IsWrite && !isFunctionScopeIdentifiedObject(UnderlyingObj)) ||
+ (!IsWrite && (!AreAllWritesIdentified ||
+ !isa<Argument>(UnderlyingObj)) &&
+ !isIdentifiedObject(UnderlyingObj))) {
+ DEBUG(dbgs() << "LV: Found an unidentified " <<
+ (IsWrite ? "write" : "read" ) << " ptr: " << *UnderlyingObj <<
+ "\n");
+ IsRTCheckNeeded = (IsRTCheckNeeded ||
+ !isIdentifiedObject(UnderlyingObj) ||
+ !AreAllReadsIdentified);
+
+ if (IsWrite)
+ AreAllWritesIdentified = false;
+ if (!IsWrite)
+ AreAllReadsIdentified = false;
+ }
+
+ // If this is a write - check other reads and writes for conflicts. If
+ // this is a read only check other writes for conflicts (but only if there
+ // is no other write to the ptr - this is an optimization to catch "a[i] =
+ // a[i] + " without having to do a dependence check).
+ if ((IsWrite || IsReadOnlyPtr) && WriteObjects.count(UnderlyingObj))
+ NeedDepCheck = true;
+
+ if (IsWrite)
+ WriteObjects.insert(UnderlyingObj);
+
+ // Create sets of pointers connected by shared underlying objects.
+ UnderlyingObjToAccessMap::iterator Prev =
+ ObjToLastAccess.find(UnderlyingObj);
+ if (Prev != ObjToLastAccess.end())
+ DepCands.unionSets(Access, Prev->second);
+
+ ObjToLastAccess[UnderlyingObj] = Access;
+ }
+
+ if (NeedDepCheck)
+ CheckDeps.insert(Access);
+ }
+}
+
+namespace {
+/// \brief Checks memory dependences among accesses to the same underlying
+/// object to determine whether there vectorization is legal or not (and at
+/// which vectorization factor).
+///
+/// This class works under the assumption that we already checked that memory
+/// locations with different underlying pointers are "must-not alias".
+/// We use the ScalarEvolution framework to symbolically evalutate access
+/// functions pairs. Since we currently don't restructure the loop we can rely
+/// on the program order of memory accesses to determine their safety.
+/// At the moment we will only deem accesses as safe for:
+/// * A negative constant distance assuming program order.
+///
+/// Safe: tmp = a[i + 1]; OR a[i + 1] = x;
+/// a[i] = tmp; y = a[i];
+///
+/// The latter case is safe because later checks guarantuee that there can't
+/// be a cycle through a phi node (that is, we check that "x" and "y" is not
+/// the same variable: a header phi can only be an induction or a reduction, a
+/// reduction can't have a memory sink, an induction can't have a memory
+/// source). This is important and must not be violated (or we have to
+/// resort to checking for cycles through memory).
+///
+/// * A positive constant distance assuming program order that is bigger
+/// than the biggest memory access.
+///
+/// tmp = a[i] OR b[i] = x
+/// a[i+2] = tmp y = b[i+2];
+///
+/// Safe distance: 2 x sizeof(a[0]), and 2 x sizeof(b[0]), respectively.
+///
+/// * Zero distances and all accesses have the same size.
+///
+class MemoryDepChecker {
+public:
+ typedef PointerIntPair<Value *, 1, bool> MemAccessInfo;
+ typedef SmallPtrSet<MemAccessInfo, 8> MemAccessInfoSet;
+
+ MemoryDepChecker(ScalarEvolution *Se, DataLayout *Dl, const Loop *L)
+ : SE(Se), DL(Dl), InnermostLoop(L), AccessIdx(0),
+ ShouldRetryWithRuntimeCheck(false) {}
+
+ /// \brief Register the location (instructions are given increasing numbers)
+ /// of a write access.
+ void addAccess(StoreInst *SI) {
+ Value *Ptr = SI->getPointerOperand();
+ Accesses[MemAccessInfo(Ptr, true)].push_back(AccessIdx);
+ InstMap.push_back(SI);
+ ++AccessIdx;
+ }
+
+ /// \brief Register the location (instructions are given increasing numbers)
+ /// of a write access.
+ void addAccess(LoadInst *LI) {
+ Value *Ptr = LI->getPointerOperand();
+ Accesses[MemAccessInfo(Ptr, false)].push_back(AccessIdx);
+ InstMap.push_back(LI);
+ ++AccessIdx;
+ }
+
+ /// \brief Check whether the dependencies between the accesses are safe.
+ ///
+ /// Only checks sets with elements in \p CheckDeps.
+ bool areDepsSafe(AccessAnalysis::DepCandidates &AccessSets,
+ MemAccessInfoSet &CheckDeps);
+
+ /// \brief The maximum number of bytes of a vector register we can vectorize
+ /// the accesses safely with.
+ unsigned getMaxSafeDepDistBytes() { return MaxSafeDepDistBytes; }
+
+ /// \brief In same cases when the dependency check fails we can still
+ /// vectorize the loop with a dynamic array access check.
+ bool shouldRetryWithRuntimeCheck() { return ShouldRetryWithRuntimeCheck; }
+
+private:
+ ScalarEvolution *SE;
+ DataLayout *DL;
+ const Loop *InnermostLoop;
+
+ /// \brief Maps access locations (ptr, read/write) to program order.
+ DenseMap<MemAccessInfo, std::vector<unsigned> > Accesses;
+
+ /// \brief Memory access instructions in program order.
+ SmallVector<Instruction *, 16> InstMap;
+
+ /// \brief The program order index to be used for the next instruction.
+ unsigned AccessIdx;
+
+ // We can access this many bytes in parallel safely.
+ unsigned MaxSafeDepDistBytes;
+
+ /// \brief If we see a non-constant dependence distance we can still try to
+ /// vectorize this loop with runtime checks.
+ bool ShouldRetryWithRuntimeCheck;
+
+ /// \brief Check whether there is a plausible dependence between the two
+ /// accesses.
+ ///
+ /// Access \p A must happen before \p B in program order. The two indices
+ /// identify the index into the program order map.
+ ///
+ /// This function checks whether there is a plausible dependence (or the
+ /// absence of such can't be proved) between the two accesses. If there is a
+ /// plausible dependence but the dependence distance is bigger than one
+ /// element access it records this distance in \p MaxSafeDepDistBytes (if this
+ /// distance is smaller than any other distance encountered so far).
+ /// Otherwise, this function returns true signaling a possible dependence.
+ bool isDependent(const MemAccessInfo &A, unsigned AIdx,
+ const MemAccessInfo &B, unsigned BIdx);
+
+ /// \brief Check whether the data dependence could prevent store-load
+ /// forwarding.
+ bool couldPreventStoreLoadForward(unsigned Distance, unsigned TypeByteSize);
+};
+
+} // end anonymous namespace
+
+static bool isInBoundsGep(Value *Ptr) {
+ if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr))
+ return GEP->isInBounds();
+ return false;
+}
+
+/// \brief Check whether the access through \p Ptr has a constant stride.
+static int isStridedPtr(ScalarEvolution *SE, DataLayout *DL, Value *Ptr,
+ const Loop *Lp) {
+ const Type *Ty = Ptr->getType();
+ assert(Ty->isPointerTy() && "Unexpected non-ptr");
+
+ // Make sure that the pointer does not point to aggregate types.
+ const PointerType *PtrTy = cast<PointerType>(Ty);
+ if (PtrTy->getElementType()->isAggregateType()) {
+ DEBUG(dbgs() << "LV: Bad stride - Not a pointer to a scalar type" << *Ptr <<
+ "\n");
+ return 0;
+ }
+
+ const SCEV *PtrScev = SE->getSCEV(Ptr);
+ const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PtrScev);
+ if (!AR) {
+ DEBUG(dbgs() << "LV: Bad stride - Not an AddRecExpr pointer "
+ << *Ptr << " SCEV: " << *PtrScev << "\n");
+ return 0;
+ }
+
+ // The accesss function must stride over the innermost loop.
+ if (Lp != AR->getLoop()) {
+ DEBUG(dbgs() << "LV: Bad stride - Not striding over innermost loop " <<
+ *Ptr << " SCEV: " << *PtrScev << "\n");
+ }
+
+ // The address calculation must not wrap. Otherwise, a dependence could be
+ // inverted.
+ // An inbounds getelementptr that is a AddRec with a unit stride
+ // cannot wrap per definition. The unit stride requirement is checked later.
+ // An getelementptr without an inbounds attribute and unit stride would have
+ // to access the pointer value "0" which is undefined behavior in address
+ // space 0, therefore we can also vectorize this case.
+ bool IsInBoundsGEP = isInBoundsGep(Ptr);
+ bool IsNoWrapAddRec = AR->getNoWrapFlags(SCEV::NoWrapMask);
+ bool IsInAddressSpaceZero = PtrTy->getAddressSpace() == 0;
+ if (!IsNoWrapAddRec && !IsInBoundsGEP && !IsInAddressSpaceZero) {
+ DEBUG(dbgs() << "LV: Bad stride - Pointer may wrap in the address space "
+ << *Ptr << " SCEV: " << *PtrScev << "\n");
+ return 0;
+ }
+
+ // Check the step is constant.
+ const SCEV *Step = AR->getStepRecurrence(*SE);
+
+ // Calculate the pointer stride and check if it is consecutive.
+ const SCEVConstant *C = dyn_cast<SCEVConstant>(Step);
+ if (!C) {
+ DEBUG(dbgs() << "LV: Bad stride - Not a constant strided " << *Ptr <<
+ " SCEV: " << *PtrScev << "\n");
+ return 0;
+ }
+
+ int64_t Size = DL->getTypeAllocSize(PtrTy->getElementType());
+ const APInt &APStepVal = C->getValue()->getValue();
+
+ // Huge step value - give up.
+ if (APStepVal.getBitWidth() > 64)
+ return 0;
+
+ int64_t StepVal = APStepVal.getSExtValue();
+
+ // Strided access.
+ int64_t Stride = StepVal / Size;
+ int64_t Rem = StepVal % Size;
+ if (Rem)
+ return 0;
+
+ // If the SCEV could wrap but we have an inbounds gep with a unit stride we
+ // know we can't "wrap around the address space". In case of address space
+ // zero we know that this won't happen without triggering undefined behavior.
+ if (!IsNoWrapAddRec && (IsInBoundsGEP || IsInAddressSpaceZero) &&
+ Stride != 1 && Stride != -1)
+ return 0;
+
+ return Stride;
+}
+
+bool MemoryDepChecker::couldPreventStoreLoadForward(unsigned Distance,
+ unsigned TypeByteSize) {
+ // If loads occur at a distance that is not a multiple of a feasible vector
+ // factor store-load forwarding does not take place.
+ // Positive dependences might cause troubles because vectorizing them might
+ // prevent store-load forwarding making vectorized code run a lot slower.
+ // a[i] = a[i-3] ^ a[i-8];
+ // The stores to a[i:i+1] don't align with the stores to a[i-3:i-2] and
+ // hence on your typical architecture store-load forwarding does not take
+ // place. Vectorizing in such cases does not make sense.
+ // Store-load forwarding distance.
+ const unsigned NumCyclesForStoreLoadThroughMemory = 8*TypeByteSize;
+ // Maximum vector factor.
+ unsigned MaxVFWithoutSLForwardIssues = MaxVectorWidth*TypeByteSize;
+ if(MaxSafeDepDistBytes < MaxVFWithoutSLForwardIssues)
+ MaxVFWithoutSLForwardIssues = MaxSafeDepDistBytes;
+
+ for (unsigned vf = 2*TypeByteSize; vf <= MaxVFWithoutSLForwardIssues;
+ vf *= 2) {
+ if (Distance % vf && Distance / vf < NumCyclesForStoreLoadThroughMemory) {
+ MaxVFWithoutSLForwardIssues = (vf >>=1);
+ break;
}
}
+
+ if (MaxVFWithoutSLForwardIssues< 2*TypeByteSize) {
+ DEBUG(dbgs() << "LV: Distance " << Distance <<
+ " that could cause a store-load forwarding conflict\n");
+ return true;
+ }
+
+ if (MaxVFWithoutSLForwardIssues < MaxSafeDepDistBytes &&
+ MaxVFWithoutSLForwardIssues != MaxVectorWidth*TypeByteSize)
+ MaxSafeDepDistBytes = MaxVFWithoutSLForwardIssues;
+ return false;
+}
+
+bool MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
+ const MemAccessInfo &B, unsigned BIdx) {
+ assert (AIdx < BIdx && "Must pass arguments in program order");
+
+ Value *APtr = A.getPointer();
+ Value *BPtr = B.getPointer();
+ bool AIsWrite = A.getInt();
+ bool BIsWrite = B.getInt();
+
+ // Two reads are independent.
+ if (!AIsWrite && !BIsWrite)
+ return false;
+
+ const SCEV *AScev = SE->getSCEV(APtr);
+ const SCEV *BScev = SE->getSCEV(BPtr);
+
+ int StrideAPtr = isStridedPtr(SE, DL, APtr, InnermostLoop);
+ int StrideBPtr = isStridedPtr(SE, DL, BPtr, InnermostLoop);
+
+ const SCEV *Src = AScev;
+ const SCEV *Sink = BScev;
+
+ // If the induction step is negative we have to invert source and sink of the
+ // dependence.
+ if (StrideAPtr < 0) {
+ //Src = BScev;
+ //Sink = AScev;
+ std::swap(APtr, BPtr);
+ std::swap(Src, Sink);
+ std::swap(AIsWrite, BIsWrite);
+ std::swap(AIdx, BIdx);
+ std::swap(StrideAPtr, StrideBPtr);
+ }
+
+ const SCEV *Dist = SE->getMinusSCEV(Sink, Src);
+
+ DEBUG(dbgs() << "LV: Src Scev: " << *Src << "Sink Scev: " << *Sink
+ << "(Induction step: " << StrideAPtr << ")\n");
+ DEBUG(dbgs() << "LV: Distance for " << *InstMap[AIdx] << " to "
+ << *InstMap[BIdx] << ": " << *Dist << "\n");
+
+ // Need consecutive accesses. We don't want to vectorize
+ // "A[B[i]] += ..." and similar code or pointer arithmetic that could wrap in
+ // the address space.
+ if (!StrideAPtr || !StrideBPtr || StrideAPtr != StrideBPtr){
+ DEBUG(dbgs() << "Non-consecutive pointer access\n");
+ return true;
+ }
+
+ const SCEVConstant *C = dyn_cast<SCEVConstant>(Dist);
+ if (!C) {
+ DEBUG(dbgs() << "LV: Dependence because of non-constant distance\n");
+ ShouldRetryWithRuntimeCheck = true;
+ return true;
+ }
+
+ Type *ATy = APtr->getType()->getPointerElementType();
+ Type *BTy = BPtr->getType()->getPointerElementType();
+ unsigned TypeByteSize = DL->getTypeAllocSize(ATy);
+
+ // Negative distances are not plausible dependencies.
+ const APInt &Val = C->getValue()->getValue();
+ if (Val.isNegative()) {
+ bool IsTrueDataDependence = (AIsWrite && !BIsWrite);
+ if (IsTrueDataDependence &&
+ (couldPreventStoreLoadForward(Val.abs().getZExtValue(), TypeByteSize) ||
+ ATy != BTy))
+ return true;
+
+ DEBUG(dbgs() << "LV: Dependence is negative: NoDep\n");
+ return false;
+ }
+
+ // Write to the same location with the same size.
+ // Could be improved to assert type sizes are the same (i32 == float, etc).
+ if (Val == 0) {
+ if (ATy == BTy)
+ return false;
+ DEBUG(dbgs() << "LV: Zero dependence difference but different types\n");
+ return true;
+ }
+
+ assert(Val.isStrictlyPositive() && "Expect a positive value");
+
+ // Positive distance bigger than max vectorization factor.
+ if (ATy != BTy) {
+ DEBUG(dbgs() <<
+ "LV: ReadWrite-Write positive dependency with different types\n");
+ return false;
+ }
+
+ unsigned Distance = (unsigned) Val.getZExtValue();
+
+ // Bail out early if passed-in parameters make vectorization not feasible.
+ unsigned ForcedFactor = VectorizationFactor ? VectorizationFactor : 1;
+ unsigned ForcedUnroll = VectorizationUnroll ? VectorizationUnroll : 1;
+
+ // The distance must be bigger than the size needed for a vectorized version
+ // of the operation and the size of the vectorized operation must not be
+ // bigger than the currrent maximum size.
+ if (Distance < 2*TypeByteSize ||
+ 2*TypeByteSize > MaxSafeDepDistBytes ||
+ Distance < TypeByteSize * ForcedUnroll * ForcedFactor) {
+ DEBUG(dbgs() << "LV: Failure because of Positive distance "
+ << Val.getSExtValue() << '\n');
+ return true;
+ }
+
+ MaxSafeDepDistBytes = Distance < MaxSafeDepDistBytes ?
+ Distance : MaxSafeDepDistBytes;
+
+ bool IsTrueDataDependence = (!AIsWrite && BIsWrite);
+ if (IsTrueDataDependence &&
+ couldPreventStoreLoadForward(Distance, TypeByteSize))
+ return true;
+
+ DEBUG(dbgs() << "LV: Positive distance " << Val.getSExtValue() <<
+ " with max VF = " << MaxSafeDepDistBytes / TypeByteSize << '\n');
+
+ return false;
+}
+
+bool
+MemoryDepChecker::areDepsSafe(AccessAnalysis::DepCandidates &AccessSets,
+ MemAccessInfoSet &CheckDeps) {
+
+ MaxSafeDepDistBytes = -1U;
+ while (!CheckDeps.empty()) {
+ MemAccessInfo CurAccess = *CheckDeps.begin();
+
+ // Get the relevant memory access set.
+ EquivalenceClasses<MemAccessInfo>::iterator I =
+ AccessSets.findValue(AccessSets.getLeaderValue(CurAccess));
+
+ // Check accesses within this set.
+ EquivalenceClasses<MemAccessInfo>::member_iterator AI, AE;
+ AI = AccessSets.member_begin(I), AE = AccessSets.member_end();
+
+ // Check every access pair.
+ while (AI != AE) {
+ CheckDeps.erase(*AI);
+ EquivalenceClasses<MemAccessInfo>::member_iterator OI = llvm::next(AI);
+ while (OI != AE) {
+ // Check every accessing instruction pair in program order.
+ for (std::vector<unsigned>::iterator I1 = Accesses[*AI].begin(),
+ I1E = Accesses[*AI].end(); I1 != I1E; ++I1)
+ for (std::vector<unsigned>::iterator I2 = Accesses[*OI].begin(),
+ I2E = Accesses[*OI].end(); I2 != I2E; ++I2) {
+ if (*I1 < *I2 && isDependent(*AI, *I1, *OI, *I2))
+ return false;
+ if (*I2 < *I1 && isDependent(*OI, *I2, *AI, *I1))
+ return false;
+ }
+ ++OI;
+ }
+ AI++;
+ }
+ }
+ return true;
}
bool LoopVectorizationLegality::canVectorizeMemory() {
+
typedef SmallVector<Value*, 16> ValueVector;
typedef SmallPtrSet<Value*, 16> ValueSet;
+
// Holds the Load and Store *instructions*.
ValueVector Loads;
ValueVector Stores;
+
+ // Holds all the different accesses in the loop.
+ unsigned NumReads = 0;
+ unsigned NumReadWrites = 0;
+
PtrRtCheck.Pointers.clear();
PtrRtCheck.Need = false;
+ const bool IsAnnotatedParallel = TheLoop->isAnnotatedParallel();
+ MemoryDepChecker DepChecker(SE, DL, TheLoop);
+
// For each block.
for (Loop::block_iterator bb = TheLoop->block_begin(),
be = TheLoop->block_end(); bb != be; ++bb) {
// but is not a load, then we quit. Notice that we don't handle function
// calls that read or write.
if (it->mayReadFromMemory()) {
+ // Many math library functions read the rounding mode. We will only
+ // vectorize a loop if it contains known function calls that don't set
+ // the flag. Therefore, it is safe to ignore this read from memory.
+ CallInst *Call = dyn_cast<CallInst>(it);
+ if (Call && getIntrinsicIDForCall(Call, TLI))
+ continue;
+
LoadInst *Ld = dyn_cast<LoadInst>(it);
if (!Ld) return false;
- if (!Ld->isSimple()) {
+ if (!Ld->isSimple() && !IsAnnotatedParallel) {
DEBUG(dbgs() << "LV: Found a non-simple load.\n");
return false;
}
Loads.push_back(Ld);
+ DepChecker.addAccess(Ld);
continue;
}
if (it->mayWriteToMemory()) {
StoreInst *St = dyn_cast<StoreInst>(it);
if (!St) return false;
- if (!St->isSimple()) {
+ if (!St->isSimple() && !IsAnnotatedParallel) {
DEBUG(dbgs() << "LV: Found a non-simple store.\n");
return false;
}
Stores.push_back(St);
+ DepChecker.addAccess(St);
}
- } // next instr.
- } // next block.
+ } // Next instr.
+ } // Next block.
// Now we have two lists that hold the loads and the stores.
// Next, we find the pointers that they use.
return true;
}
- // Holds the read and read-write *pointers* that we find.
- ValueVector Reads;
- ValueVector ReadWrites;
+ AccessAnalysis::DepCandidates DependentAccesses;
+ AccessAnalysis Accesses(DL, DependentAccesses);
// Holds the analyzed pointers. We don't want to call GetUnderlyingObjects
// multiple times on the same object. If the ptr is accessed twice, once
return false;
}
- // 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);
+ // 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)) {
+ ++NumReadWrites;
+ Accesses.addStore(Ptr);
+ }
+ }
+
+ if (IsAnnotatedParallel) {
+ DEBUG(dbgs()
+ << "LV: A loop annotated parallel, ignore memory dependency "
+ << "checks.\n");
+ return true;
}
for (I = Loads.begin(), IE = Loads.end(); I != IE; ++I) {
// 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) || 0 == isConsecutivePtr(Ptr))
- Reads.push_back(Ptr);
+ bool IsReadOnlyPtr = false;
+ if (Seen.insert(Ptr) || !isStridedPtr(SE, DL, Ptr, TheLoop)) {
+ ++NumReads;
+ IsReadOnlyPtr = true;
+ }
+ Accesses.addLoad(Ptr, IsReadOnlyPtr);
}
// If we write (or read-write) to a single destination and there are no
// other reads in this loop then is it safe to vectorize.
- if (ReadWrites.size() == 1 && Reads.size() == 0) {
+ if (NumReadWrites == 1 && NumReads == 0) {
DEBUG(dbgs() << "LV: Found a write-only loop!\n");
return true;
}
+ // Build dependence sets and check whether we need a runtime pointer bounds
+ // check.
+ Accesses.buildDependenceSets();
+ bool NeedRTCheck = Accesses.isRTCheckNeeded();
+
// Find pointers with computable bounds. We are going to use this information
// to place a runtime bound check.
- bool CanDoRT = true;
- for (I = ReadWrites.begin(), IE = ReadWrites.end(); I != IE; ++I)
- if (hasComputableBounds(*I)) {
- PtrRtCheck.insert(SE, TheLoop, *I);
- DEBUG(dbgs() << "LV: Found a runtime check ptr:" << **I <<"\n");
- } else {
- CanDoRT = false;
- break;
- }
- for (I = Reads.begin(), IE = Reads.end(); I != IE; ++I)
- if (hasComputableBounds(*I)) {
- PtrRtCheck.insert(SE, TheLoop, *I);
- DEBUG(dbgs() << "LV: Found a runtime check ptr:" << **I <<"\n");
- } else {
- CanDoRT = false;
- break;
- }
+ unsigned NumComparisons = 0;
+ bool CanDoRT = false;
+ if (NeedRTCheck)
+ CanDoRT = Accesses.canCheckPtrAtRT(PtrRtCheck, NumComparisons, SE, TheLoop);
+
- // Check that we did not collect too many pointers or found a
- // unsizeable pointer.
- if (!CanDoRT || PtrRtCheck.Pointers.size() > RuntimeMemoryCheckThreshold) {
+ DEBUG(dbgs() << "LV: We need to do " << NumComparisons <<
+ " pointer comparisons.\n");
+
+ // If we only have one set of dependences to check pointers among we don't
+ // need a runtime check.
+ if (NumComparisons == 0 && NeedRTCheck)
+ NeedRTCheck = false;
+
+ // Check that we did not collect too many pointers or found an unsizeable
+ // pointer.
+ if (!CanDoRT || NumComparisons > RuntimeMemoryCheckThreshold) {
PtrRtCheck.reset();
CanDoRT = false;
}
DEBUG(dbgs() << "LV: We can perform a memory runtime check if needed.\n");
}
- bool NeedRTCheck = false;
-
- // 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;
- ValueVector TempObjects;
-
- // Check that the read-writes do not conflict with other read-write
- // pointers.
- bool AllWritesIdentified = true;
- 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");
- NeedRTCheck = true;
- AllWritesIdentified = false;
- }
- if (!WriteObjects.insert(*it)) {
- DEBUG(dbgs() << "LV: Found a possible write-write reorder:"
- << **it <<"\n");
- return false;
- }
- }
- TempObjects.clear();
+ if (NeedRTCheck && !CanDoRT) {
+ DEBUG(dbgs() << "LV: We can't vectorize because we can't find " <<
+ "the array bounds.\n");
+ PtrRtCheck.reset();
+ return false;
}
- /// 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 all of the writes are identified then we don't care if the read
- // pointer is identified or not.
- if (!AllWritesIdentified && !isIdentifiedObject(*it)) {
- DEBUG(dbgs() << "LV: Found an unidentified read ptr:"<< **it <<"\n");
- NeedRTCheck = true;
- }
- if (WriteObjects.count(*it)) {
- DEBUG(dbgs() << "LV: Found a possible read/write reorder:"
- << **it <<"\n");
+ PtrRtCheck.Need = NeedRTCheck;
+
+ bool CanVecMem = true;
+ if (Accesses.isDependencyCheckNeeded()) {
+ DEBUG(dbgs() << "LV: Checking memory dependencies\n");
+ CanVecMem = DepChecker.areDepsSafe(DependentAccesses,
+ Accesses.getDependenciesToCheck());
+ MaxSafeDepDistBytes = DepChecker.getMaxSafeDepDistBytes();
+
+ if (!CanVecMem && DepChecker.shouldRetryWithRuntimeCheck()) {
+ DEBUG(dbgs() << "LV: Retrying with memory checks\n");
+ NeedRTCheck = true;
+
+ // Clear the dependency checks. We assume they are not needed.
+ Accesses.resetDepChecks();
+
+ PtrRtCheck.reset();
+ PtrRtCheck.Need = true;
+
+ CanDoRT = Accesses.canCheckPtrAtRT(PtrRtCheck, NumComparisons, SE,
+ TheLoop, true);
+ // Check that we did not collect too many pointers or found an unsizeable
+ // pointer.
+ if (!CanDoRT || NumComparisons > RuntimeMemoryCheckThreshold) {
+ DEBUG(dbgs() << "LV: Can't vectorize with memory checks\n");
+ PtrRtCheck.reset();
return false;
}
+
+ CanVecMem = true;
}
- TempObjects.clear();
}
- 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 CanVecMem;
+}
+
+static bool hasMultipleUsesOf(Instruction *I,
+ SmallPtrSet<Instruction *, 8> &Insts) {
+ unsigned NumUses = 0;
+ for(User::op_iterator Use = I->op_begin(), E = I->op_end(); Use != E; ++Use) {
+ if (Insts.count(dyn_cast<Instruction>(*Use)))
+ ++NumUses;
+ if (NumUses > 1)
+ return true;
}
- DEBUG(dbgs() << "LV: We "<< (NeedRTCheck ? "" : "don't") <<
- " need a runtime memory check.\n");
+ return false;
+}
+
+static bool areAllUsesIn(Instruction *I, SmallPtrSet<Instruction *, 8> &Set) {
+ for(User::op_iterator Use = I->op_begin(), E = I->op_end(); Use != E; ++Use)
+ if (!Set.count(dyn_cast<Instruction>(*Use)))
+ return false;
return true;
}
// 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 reduction operation in our scan.
+ bool FoundReduxOp = false;
+
+ // We start with the PHI node and scan for all of the users of this
+ // instruction. All users must be instructions that can be used as reduction
+ // variables (such as ADD). We must have a single out-of-block user. The cycle
+ // must include the original PHI.
+ bool FoundStartPHI = false;
+
+ // To recognize min/max patterns formed by a icmp select sequence, we store
+ // the number of instruction we saw from the recognized min/max pattern,
+ // to make sure we only see exactly the two instructions.
+ unsigned NumCmpSelectPatternInst = 0;
+ ReductionInstDesc ReduxDesc(false, 0);
+
+ SmallPtrSet<Instruction *, 8> VisitedInsts;
+ SmallVector<Instruction *, 8> Worklist;
+ Worklist.push_back(Phi);
+ VisitedInsts.insert(Phi);
+
+ // A value in the reduction can be used:
+ // - By the reduction:
+ // - Reduction operation:
+ // - One use of reduction value (safe).
+ // - Multiple use of reduction value (not safe).
+ // - PHI:
+ // - All uses of the PHI must be the reduction (safe).
+ // - Otherwise, not safe.
+ // - By one instruction outside of the loop (safe).
+ // - By further instructions outside of the loop (not safe).
+ // - By an instruction that is not part of the reduction (not safe).
+ // This is either:
+ // * An instruction type other than PHI or the reduction operation.
+ // * A PHI in the header other than the initial PHI.
+ while (!Worklist.empty()) {
+ Instruction *Cur = Worklist.back();
+ Worklist.pop_back();
- // 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 that can be
- // used as reduction variables (such as ADD). We may have a single
- // out-of-block user. The cycle must end with the original PHI.
- Instruction *Iter = Phi;
- while (true) {
- // If the instruction has no users then this is a broken
- // chain and can't be a reduction variable.
- if (Iter->use_empty())
+ // No Users.
+ // If the instruction has no users then this is a broken chain and can't be
+ // a reduction variable.
+ if (Cur->use_empty())
return false;
- // Any reduction instr must be of one of the allowed kinds.
- if (!isReductionInstr(Iter, Kind))
+ bool IsAPhi = isa<PHINode>(Cur);
+
+ // A header PHI use other than the original PHI.
+ if (Cur != Phi && IsAPhi && Cur->getParent() == Phi->getParent())
return false;
- // Did we find a user inside this loop already ?
- bool FoundInBlockUser = false;
- // Did we reach the initial PHI node already ?
- bool FoundStartPHI = false;
-
- // For each of the *users* of iter.
- for (Value::use_iterator it = Iter->use_begin(), e = Iter->use_end();
- it != e; ++it) {
- Instruction *U = cast<Instruction>(*it);
- // We already know that the PHI is a user.
- if (U == Phi) {
- FoundStartPHI = true;
- continue;
- }
+ // Reductions of instructions such as Div, and Sub is only possible if the
+ // LHS is the reduction variable.
+ if (!Cur->isCommutative() && !IsAPhi && !isa<SelectInst>(Cur) &&
+ !isa<ICmpInst>(Cur) && !isa<FCmpInst>(Cur) &&
+ !VisitedInsts.count(dyn_cast<Instruction>(Cur->getOperand(0))))
+ return false;
+
+ // Any reduction instruction must be of one of the allowed kinds.
+ ReduxDesc = isReductionInstr(Cur, Kind, ReduxDesc);
+ if (!ReduxDesc.IsReduction)
+ return false;
+
+ // A reduction operation must only have one use of the reduction value.
+ if (!IsAPhi && Kind != RK_IntegerMinMax && Kind != RK_FloatMinMax &&
+ hasMultipleUsesOf(Cur, VisitedInsts))
+ return false;
+
+ // All inputs to a PHI node must be a reduction value.
+ if(IsAPhi && Cur != Phi && !areAllUsesIn(Cur, VisitedInsts))
+ return false;
+
+ if (Kind == RK_IntegerMinMax && (isa<ICmpInst>(Cur) ||
+ isa<SelectInst>(Cur)))
+ ++NumCmpSelectPatternInst;
+ if (Kind == RK_FloatMinMax && (isa<FCmpInst>(Cur) ||
+ isa<SelectInst>(Cur)))
+ ++NumCmpSelectPatternInst;
+
+ // Check whether we found a reduction operator.
+ FoundReduxOp |= !IsAPhi;
+
+ // Process users of current instruction. Push non-PHI nodes after PHI nodes
+ // onto the stack. This way we are going to have seen all inputs to PHI
+ // nodes once we get to them.
+ SmallVector<Instruction *, 8> NonPHIs;
+ SmallVector<Instruction *, 8> PHIs;
+ for (Value::use_iterator UI = Cur->use_begin(), E = Cur->use_end(); UI != E;
+ ++UI) {
+ Instruction *Usr = cast<Instruction>(*UI);
// Check if we found the exit user.
- BasicBlock *Parent = U->getParent();
+ BasicBlock *Parent = Usr->getParent();
if (!TheLoop->contains(Parent)) {
- // Exit if you find multiple outside users.
- if (ExitInstruction != 0)
+ // Exit if you find multiple outside users or if the header phi node is
+ // being used. In this case the user uses the value of the previous
+ // iteration, in which case we would loose "VF-1" iterations of the
+ // reduction operation if we vectorize.
+ if (ExitInstruction != 0 || Cur == Phi)
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->getNumUses() > 1)
+ // The instruction used by an outside user must be the last instruction
+ // before we feed back to the reduction phi. Otherwise, we loose VF-1
+ // operations on the value.
+ if (std::find(Phi->op_begin(), Phi->op_end(), Cur) == Phi->op_end())
+ return false;
+
+ ExitInstruction = Cur;
continue;
+ }
- // We can't have multiple inside users.
- if (FoundInBlockUser)
- return false;
- FoundInBlockUser = true;
- Iter = U;
+ // Process instructions only once (termination).
+ if (VisitedInsts.insert(Usr)) {
+ if (isa<PHINode>(Usr))
+ PHIs.push_back(Usr);
+ else
+ NonPHIs.push_back(Usr);
+ }
+ // Remember that we completed the cycle.
+ if (Usr == Phi)
+ FoundStartPHI = true;
}
+ Worklist.append(PHIs.begin(), PHIs.end());
+ Worklist.append(NonPHIs.begin(), NonPHIs.end());
+ }
- // 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);
+ // This means we have seen one but not the other instruction of the
+ // pattern or more than just a select and cmp.
+ if ((Kind == RK_IntegerMinMax || Kind == RK_FloatMinMax) &&
+ NumCmpSelectPatternInst != 2)
+ return false;
- // Save the description of this reduction variable.
- ReductionDescriptor RD(RdxStart, ExitInstruction, Kind);
- Reductions[Phi] = RD;
- return true;
- }
+ if (!FoundStartPHI || !FoundReduxOp || !ExitInstruction)
+ return false;
- // If we've reached the start PHI but did not find an outside user then
- // this is dead code. Abort.
- if (FoundStartPHI)
- 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.
+
+ // 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,
+ ReduxDesc.MinMaxKind);
+ 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 true;
+}
+
+/// Returns true if the instruction is a Select(ICmp(X, Y), X, Y) instruction
+/// pattern corresponding to a min(X, Y) or max(X, Y).
+LoopVectorizationLegality::ReductionInstDesc
+LoopVectorizationLegality::isMinMaxSelectCmpPattern(Instruction *I,
+ ReductionInstDesc &Prev) {
+
+ assert((isa<ICmpInst>(I) || isa<FCmpInst>(I) || isa<SelectInst>(I)) &&
+ "Expect a select instruction");
+ Instruction *Cmp = 0;
+ SelectInst *Select = 0;
+
+ // We must handle the select(cmp()) as a single instruction. Advance to the
+ // select.
+ if ((Cmp = dyn_cast<ICmpInst>(I)) || (Cmp = dyn_cast<FCmpInst>(I))) {
+ if (!Cmp->hasOneUse() || !(Select = dyn_cast<SelectInst>(*I->use_begin())))
+ return ReductionInstDesc(false, I);
+ return ReductionInstDesc(Select, Prev.MinMaxKind);
}
+
+ // Only handle single use cases for now.
+ if (!(Select = dyn_cast<SelectInst>(I)))
+ return ReductionInstDesc(false, I);
+ if (!(Cmp = dyn_cast<ICmpInst>(I->getOperand(0))) &&
+ !(Cmp = dyn_cast<FCmpInst>(I->getOperand(0))))
+ return ReductionInstDesc(false, I);
+ if (!Cmp->hasOneUse())
+ return ReductionInstDesc(false, I);
+
+ Value *CmpLeft;
+ Value *CmpRight;
+
+ // Look for a min/max pattern.
+ if (m_UMin(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
+ return ReductionInstDesc(Select, MRK_UIntMin);
+ else if (m_UMax(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
+ return ReductionInstDesc(Select, MRK_UIntMax);
+ else if (m_SMax(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
+ return ReductionInstDesc(Select, MRK_SIntMax);
+ else if (m_SMin(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
+ return ReductionInstDesc(Select, MRK_SIntMin);
+ else if (m_OrdFMin(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
+ return ReductionInstDesc(Select, MRK_FloatMin);
+ else if (m_OrdFMax(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
+ return ReductionInstDesc(Select, MRK_FloatMax);
+ else if (m_UnordFMin(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
+ return ReductionInstDesc(Select, MRK_FloatMin);
+ else if (m_UnordFMax(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
+ return ReductionInstDesc(Select, MRK_FloatMax);
+
+ return ReductionInstDesc(false, I);
}
-bool
+LoopVectorizationLegality::ReductionInstDesc
LoopVectorizationLegality::isReductionInstr(Instruction *I,
- ReductionKind Kind) {
+ ReductionKind Kind,
+ ReductionInstDesc &Prev) {
+ bool FP = I->getType()->isFloatingPointTy();
+ bool FastMath = (FP && I->isCommutative() && I->isAssociative());
switch (I->getOpcode()) {
default:
- return false;
+ return ReductionInstDesc(false, I);
case Instruction::PHI:
- // possibly.
- return true;
- case Instruction::Add:
+ if (FP && (Kind != RK_FloatMult && Kind != RK_FloatAdd &&
+ Kind != RK_FloatMinMax))
+ return ReductionInstDesc(false, I);
+ return ReductionInstDesc(I, Prev.MinMaxKind);
case Instruction::Sub:
- return Kind == IntegerAdd;
+ case Instruction::Add:
+ return ReductionInstDesc(Kind == RK_IntegerAdd, I);
case Instruction::Mul:
- return Kind == IntegerMult;
+ return ReductionInstDesc(Kind == RK_IntegerMult, I);
case Instruction::And:
- return Kind == IntegerAnd;
+ return ReductionInstDesc(Kind == RK_IntegerAnd, I);
case Instruction::Or:
- return Kind == IntegerOr;
+ return ReductionInstDesc(Kind == RK_IntegerOr, I);
case Instruction::Xor:
- return Kind == IntegerXor;
+ return ReductionInstDesc(Kind == RK_IntegerXor, I);
+ case Instruction::FMul:
+ return ReductionInstDesc(Kind == RK_FloatMult && FastMath, I);
+ case Instruction::FAdd:
+ return ReductionInstDesc(Kind == RK_FloatAdd && FastMath, I);
+ case Instruction::FCmp:
+ case Instruction::ICmp:
+ case Instruction::Select:
+ if (Kind != RK_IntegerMinMax &&
+ (!HasFunNoNaNAttr || Kind != RK_FloatMinMax))
+ return ReductionInstDesc(false, I);
+ return isMinMaxSelectCmpPattern(I, Prev);
}
}
Type *PhiTy = Phi->getType();
// We only handle integer and pointer inductions variables.
if (!PhiTy->isIntegerTy() && !PhiTy->isPointerTy())
- return NoInduction;
+ return IK_NoInduction;
- // Check that the PHI is consecutive and starts at zero.
+ // 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 NoInduction;
+ return IK_NoInduction;
}
const SCEV *Step = AR->getStepRecurrence(*SE);
// Integer inductions need to have a stride of one.
if (PhiTy->isIntegerTy()) {
if (Step->isOne())
- return IntInduction;
+ return IK_IntInduction;
if (Step->isAllOnesValue())
- return ReverseIntInduction;
- return NoInduction;
+ 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 NoInduction;
+ 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 PtrInduction;
+ return IK_PtrInduction;
+ else if (C->getValue()->equalsInt(0 - Size))
+ return IK_ReversePtrInduction;
- return NoInduction;
+ return IK_NoInduction;
}
bool LoopVectorizationLegality::isInductionVariable(const Value *V) {
return !DT->dominates(BB, Latch);
}
-bool LoopVectorizationLegality::blockCanBePredicated(BasicBlock *BB) {
+bool LoopVectorizationLegality::blockCanBePredicated(BasicBlock *BB,
+ SmallPtrSet<Value *, 8>& SafePtrs) {
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())
+ // We might be able to hoist the load.
+ if (it->mayReadFromMemory()) {
+ LoadInst *LI = dyn_cast<LoadInst>(it);
+ if (!LI || !SafePtrs.count(LI->getPointerOperand()))
+ return false;
+ }
+
+ // We don't predicate stores at the moment.
+ if (it->mayWriteToMemory() || it->mayThrow())
return false;
// The instructions below can trap.
return true;
}
-bool LoopVectorizationLegality::hasComputableBounds(Value *Ptr) {
- const SCEV *PhiScev = SE->getSCEV(Ptr);
- const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PhiScev);
- if (!AR)
- return false;
-
- return AR->isAffine();
-}
-
-unsigned
+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 1;
+ return Factor;
}
// Find the trip count.
unsigned TC = SE->getSmallConstantTripCount(TheLoop, TheLoop->getLoopLatch());
- DEBUG(dbgs() << "LV: Found trip count:"<<TC<<"\n");
+ DEBUG(dbgs() << "LV: Found trip count: " << TC << '\n');
+
+ unsigned WidestType = getWidestType();
+ unsigned WidestRegister = TTI.getRegisterBitWidth(true);
+ unsigned MaxSafeDepDist = -1U;
+ if (Legal->getMaxSafeDepDistBytes() != -1U)
+ MaxSafeDepDist = Legal->getMaxSafeDepDistBytes() * 8;
+ WidestRegister = ((WidestRegister < MaxSafeDepDist) ?
+ WidestRegister : MaxSafeDepDist);
+ 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 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 1;
+ return Factor;
}
// Find the maximum SIMD width that can fit within the trip count.
// zero then we require a tail.
if (VF < 2) {
DEBUG(dbgs() << "LV: Aborting. A tail loop is required in Os.\n");
- return 1;
+ 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");
-
- return UserVF;
- }
+ DEBUG(dbgs() << "LV: Using user VF " << UserVF << ".\n");
- if (!VTTI) {
- DEBUG(dbgs() << "LV: No vector target information. Not vectorizing. \n");
- return 1;
+ Factor.Width = UserVF;
+ return Factor;
}
float Cost = expectedCost(1);
unsigned Width = 1;
- DEBUG(dbgs() << "LV: Scalar loop costs: "<< (int)Cost << ".\n");
+ DEBUG(dbgs() << "LV: Scalar loop costs: " << (int)Cost << ".\n");
for (unsigned i=2; i <= VF; i*=2) {
// Notice that the vector loop needs to be executed less times, so
// we need to divide the cost of the vector loops by the width of
// the vector elements.
float VectorCost = expectedCost(i) / (float)i;
- DEBUG(dbgs() << "LV: Vector loop of width "<< i << " costs: " <<
+ DEBUG(dbgs() << "LV: Vector loop of width " << i << " costs: " <<
(int)VectorCost << ".\n");
if (VectorCost < Cost) {
Cost = VectorCost;
}
DEBUG(dbgs() << "LV: Selecting VF = : "<< Width << ".\n");
- return Width;
+ Factor.Width = Width;
+ Factor.Cost = Width * Cost;
+ return Factor;
+}
+
+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();
+
+ // 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 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;
if (OptForSize)
return 1;
- unsigned TargetVectorRegisters = VTTI->getNumberOfRegisters(true);
+ // We used the distance for the unroll factor.
+ if (Legal->getMaxSafeDepDistBytes() != -1U)
+ 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");
// fit without causing spills.
unsigned UF = (TargetVectorRegisters - R.LoopInvariantRegs) / R.MaxLocalUsers;
- // We don't want to unroll the loops to the point where they do not fit into
- // the decoded cache. Assume that we only allow 32 IR instructions.
- UF = std::min(UF, (32 / R.NumInstructions));
-
// 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;
- return UF;
+ bool HasReductions = Legal->getReductionVars()->size();
+
+ // Decide if we want to unroll if we decided that it is legal to vectorize
+ // but not profitable.
+ if (VF == 1) {
+ if (TheLoop->getNumBlocks() > 1 || !HasReductions ||
+ LoopCost > SmallLoopCost)
+ return 1;
+
+ return UF;
+ }
+
+ if (HasReductions) {
+ 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 < SmallLoopCost) {
+ DEBUG(dbgs() << "LV: Unrolling to reduce branch cost.\n");
+ unsigned NewUF = SmallLoopCost / (LoopCost + 1);
+ return std::min(NewUF, UF);
+ }
+
+ DEBUG(dbgs() << "LV: Not Unrolling.\n");
+ return 1;
}
LoopVectorizationCostModel::RegisterUsage
// Remove all of the instructions that end at this location.
InstrList &List = TransposeEnds[i];
- for (unsigned int i=0, e = List.size(); i < e; ++i)
- OpenIntervals.erase(List[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");
+ 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");
+ 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;
// 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");
+ BlockCost += 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)
+ if (VF == 1 && Legal->blockNeedsPredication(*bb))
BlockCost /= 2;
Cost += BlockCost;
return Cost;
}
+/// \brief Check whether the address computation for a non-consecutive memory
+/// access looks like an unlikely candidate for being merged into the indexing
+/// mode.
+///
+/// We look for a GEP which has one index that is an induction variable and all
+/// other indices are loop invariant. If the stride of this access is also
+/// within a small bound we decide that this address computation can likely be
+/// merged into the addressing mode.
+/// In all other cases, we identify the address computation as complex.
+static bool isLikelyComplexAddressComputation(Value *Ptr,
+ LoopVectorizationLegality *Legal,
+ ScalarEvolution *SE,
+ const Loop *TheLoop) {
+ GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
+ if (!Gep)
+ return true;
+
+ // We are looking for a gep with all loop invariant indices except for one
+ // which should be an induction variable.
+ unsigned NumOperands = Gep->getNumOperands();
+ for (unsigned i = 1; i < NumOperands; ++i) {
+ Value *Opd = Gep->getOperand(i);
+ if (!SE->isLoopInvariant(SE->getSCEV(Opd), TheLoop) &&
+ !Legal->isInductionVariable(Opd))
+ return true;
+ }
+
+ // Now we know we have a GEP ptr, %inv, %ind, %inv. Make sure that the step
+ // can likely be merged into the address computation.
+ unsigned MaxMergeDistance = 64;
+
+ const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(SE->getSCEV(Ptr));
+ if (!AddRec)
+ return true;
+
+ // Check the step is constant.
+ const SCEV *Step = AddRec->getStepRecurrence(*SE);
+ // Calculate the pointer stride and check if it is consecutive.
+ const SCEVConstant *C = dyn_cast<SCEVConstant>(Step);
+ if (!C)
+ return true;
+
+ const APInt &APStepVal = C->getValue()->getValue();
+
+ // Huge step value - give up.
+ if (APStepVal.getBitWidth() > 64)
+ return true;
+
+ int64_t StepVal = APStepVal.getSExtValue();
+
+ return StepVal > MaxMergeDistance;
+}
+
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))
// 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.
+ // 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 VTTI->getCFInstrCost(I->getOpcode());
+ return TTI.getCFInstrCost(I->getOpcode());
}
case Instruction::PHI:
//TODO: IF-converted IFs become selects.
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
- case Instruction::Xor:
- return VTTI->getArithmeticInstrCost(I->getOpcode(), VectorTy);
+ 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)
+ if (!ScalarCond)
CondTy = VectorType::get(CondTy, VF);
- return VTTI->getCmpSelInstrCost(I->getOpcode(), VectorTy, CondTy);
+ return TTI.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);
+ return TTI.getCmpSelInstrCost(I->getOpcode(), VectorTy);
}
- case Instruction::Store: {
- StoreInst *SI = cast<StoreInst>(I);
- Type *ValTy = SI->getValueOperand()->getType();
+ 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 VTTI->getMemoryOpCost(I->getOpcode(), VectorTy,
- SI->getAlignment(),
- SI->getPointerAddressSpace());
-
- // Scalarized stores.
- int Stride = Legal->isConsecutivePtr(SI->getPointerOperand());
- bool Reverse = Stride < 0;
- if (0 == Stride) {
+ return TTI.getAddressComputationCost(VectorTy) +
+ TTI.getMemoryOpCost(I->getOpcode(), VectorTy, Alignment, AS);
+
+ // Scalarized loads/stores.
+ int ConsecutiveStride = Legal->isConsecutivePtr(Ptr);
+ bool Reverse = ConsecutiveStride < 0;
+ unsigned ScalarAllocatedSize = DL->getTypeAllocSize(ValTy);
+ unsigned VectorElementSize = DL->getTypeStoreSize(VectorTy)/VF;
+ if (!ConsecutiveStride || ScalarAllocatedSize != VectorElementSize) {
+ bool IsComplexComputation =
+ isLikelyComplexAddressComputation(Ptr, Legal, SE, TheLoop);
unsigned Cost = 0;
-
// The cost of extracting from the value vector and pointer vector.
- Type *PtrTy = ToVectorTy(I->getOperand(0)->getType(), VF);
+ Type *PtrTy = ToVectorTy(Ptr->getType(), VF);
for (unsigned i = 0; i < VF; ++i) {
- Cost += VTTI->getVectorInstrCost(Instruction::ExtractElement,
- VectorTy, i);
- Cost += VTTI->getVectorInstrCost(Instruction::ExtractElement,
- PtrTy, 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);
}
- // The cost of the scalar stores.
- Cost += VF * VTTI->getMemoryOpCost(I->getOpcode(),
- ValTy->getScalarType(),
- SI->getAlignment(),
- SI->getPointerAddressSpace());
+ // The cost of the scalar loads/stores.
+ Cost += VF * TTI.getAddressComputationCost(PtrTy, IsComplexComputation);
+ Cost += VF * TTI.getMemoryOpCost(I->getOpcode(), ValTy->getScalarType(),
+ Alignment, AS);
return Cost;
}
- // Wide stores.
- unsigned Cost = VTTI->getMemoryOpCost(I->getOpcode(), VectorTy,
- SI->getAlignment(),
- SI->getPointerAddressSpace());
- if (Reverse)
- Cost += VTTI->getShuffleCost(VectorTargetTransformInfo::Reverse,
- VectorTy, 0);
- return Cost;
- }
- case Instruction::Load: {
- LoadInst *LI = cast<LoadInst>(I);
-
- if (VF == 1)
- return VTTI->getMemoryOpCost(I->getOpcode(), VectorTy,
- LI->getAlignment(),
- LI->getPointerAddressSpace());
-
- // Scalarized loads.
- int Stride = Legal->isConsecutivePtr(LI->getPointerOperand());
- bool Reverse = Stride < 0;
- if (0 == Stride) {
- unsigned Cost = 0;
- Type *PtrTy = ToVectorTy(I->getOperand(0)->getType(), VF);
-
- // The cost of extracting from the pointer vector.
- for (unsigned i = 0; i < VF; ++i)
- Cost += VTTI->getVectorInstrCost(Instruction::ExtractElement,
- PtrTy, i);
-
- // The cost of inserting data to the result vector.
- for (unsigned i = 0; i < VF; ++i)
- Cost += VTTI->getVectorInstrCost(Instruction::InsertElement,
- VectorTy, i);
-
- // The cost of the scalar stores.
- Cost += VF * VTTI->getMemoryOpCost(I->getOpcode(),
- RetTy->getScalarType(),
- LI->getAlignment(),
- LI->getPointerAddressSpace());
- return Cost;
- }
+ // Wide load/stores.
+ unsigned Cost = TTI.getAddressComputationCost(VectorTy);
+ Cost += TTI.getMemoryOpCost(I->getOpcode(), VectorTy, Alignment, AS);
- // Wide loads.
- unsigned Cost = VTTI->getMemoryOpCost(I->getOpcode(), VectorTy,
- LI->getAlignment(),
- LI->getPointerAddressSpace());
if (Reverse)
- Cost += VTTI->getShuffleCost(VectorTargetTransformInfo::Reverse,
- VectorTy, 0);
+ Cost += TTI.getShuffleCost(TargetTransformInfo::SK_Reverse,
+ VectorTy, 0);
return Cost;
}
case Instruction::ZExt:
// The cost of these is the same as the scalar operation.
if (I->getOpcode() == Instruction::Trunc &&
Legal->isInductionVariable(I->getOperand(0)))
- return VTTI->getCastInstrCost(I->getOpcode(), I->getType(),
- I->getOperand(0)->getType());
+ return TTI.getCastInstrCost(I->getOpcode(), I->getType(),
+ I->getOperand(0)->getType());
Type *SrcVecTy = ToVectorTy(I->getOperand(0)->getType(), VF);
- return VTTI->getCastInstrCost(I->getOpcode(), VectorTy, SrcVecTy);
+ return TTI.getCastInstrCost(I->getOpcode(), VectorTy, SrcVecTy);
}
case Instruction::Call: {
- assert(isTriviallyVectorizableIntrinsic(I));
- IntrinsicInst *II = cast<IntrinsicInst>(I);
- Type *RetTy = ToVectorTy(II->getType(), VF);
+ 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 = II->getNumArgOperands(); i != ie; ++i)
- Tys.push_back(ToVectorTy(II->getArgOperand(i)->getType(), VF));
- return VTTI->getIntrinsicInstrCost(II->getIntrinsicID(), RetTy, 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
unsigned Cost = 0;
if (!RetTy->isVoidTy() && VF != 1) {
- unsigned InsCost = VTTI->getVectorInstrCost(Instruction::InsertElement,
- VectorTy);
- unsigned ExtCost = VTTI->getVectorInstrCost(Instruction::ExtractElement,
- VectorTy);
+ 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.
// The cost of executing VF copies of the scalar instruction. This opcode
// is unknown. Assume that it is the same as 'mul'.
- Cost += VF * VTTI->getArithmeticInstrCost(Instruction::Mul, VectorTy);
+ Cost += VF * TTI.getArithmeticInstrCost(Instruction::Mul, VectorTy);
return Cost;
}
}// end of switch.
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(DominatorTree)
INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
+INITIALIZE_PASS_DEPENDENCY(LCSSA)
+INITIALIZE_PASS_DEPENDENCY(LoopInfo)
INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false)
namespace llvm {
- Pass *createLoopVectorizePass() {
- return new LoopVectorize();
+ Pass *createLoopVectorizePass(bool NoUnrolling, bool AlwaysVectorize) {
+ return new LoopVectorize(NoUnrolling, AlwaysVectorize);
+ }
+}
+
+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;
+}
+
+
+void InnerLoopUnroller::scalarizeInstruction(Instruction *Instr) {
+ assert(!Instr->getType()->isAggregateType() && "Can't handle vectors");
+ // Holds vector parameters or scalars, in case of uniform vals.
+ SmallVector<VectorParts, 4> Params;
+
+ setDebugLocFromInst(Builder, Instr);
+
+ // Find all of the vectorized parameters.
+ for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) {
+ Value *SrcOp = Instr->getOperand(op);
+
+ // If we are accessing the old induction variable, use the new one.
+ if (SrcOp == OldInduction) {
+ Params.push_back(getVectorValue(SrcOp));
+ continue;
+ }
+
+ // Try using previously calculated values.
+ Instruction *SrcInst = dyn_cast<Instruction>(SrcOp);
+
+ // If the src is an instruction that appeared earlier in the basic block
+ // then it should already be vectorized.
+ 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.get(SrcInst));
+ } else {
+ // The parameter is a scalar from outside the loop. Maybe even a constant.
+ VectorParts Scalars;
+ Scalars.append(UF, SrcOp);
+ Params.push_back(Scalars);
+ }
+ }
+
+ assert(Params.size() == Instr->getNumOperands() &&
+ "Invalid number of operands");
+
+ // Does this instruction return a value ?
+ bool IsVoidRetTy = Instr->getType()->isVoidTy();
+
+ Value *UndefVec = IsVoidRetTy ? 0 :
+ UndefValue::get(Instr->getType());
+ // Create a new entry in the WidenMap and initialize it to Undef or Null.
+ VectorParts &VecResults = WidenMap.splat(Instr, UndefVec);
+
+ // For each vector unroll 'part':
+ for (unsigned Part = 0; Part < UF; ++Part) {
+ // For each scalar that we create:
+
+ Instruction *Cloned = Instr->clone();
+ if (!IsVoidRetTy)
+ Cloned->setName(Instr->getName() + ".cloned");
+ // Replace the operands of the cloned instructions with extracted scalars.
+ for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) {
+ Value *Op = Params[op][Part];
+ 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] = Cloned;
}
}
+void
+InnerLoopUnroller::vectorizeMemoryInstruction(Instruction *Instr,
+ LoopVectorizationLegality*) {
+ return scalarizeInstruction(Instr);
+}
+
+Value *InnerLoopUnroller::reverseVector(Value *Vec) {
+ return Vec;
+}
+
+Value *InnerLoopUnroller::getBroadcastInstrs(Value *V) {
+ return V;
+}
+
+Value *InnerLoopUnroller::getConsecutiveVector(Value* Val, int StartIdx,
+ bool Negate) {
+ // When unrolling and the VF is 1, we only need to add a simple scalar.
+ Type *ITy = Val->getType();
+ assert(!ITy->isVectorTy() && "Val must be a scalar");
+ Constant *C = ConstantInt::get(ITy, StartIdx, Negate);
+ return Builder.CreateAdd(Val, C, "induction");
+}
projects / oota-llvm.git / blobdiff