[llvm] r214494 - SLPVectorizer: improved scheduling algorithm.

Eric Christopher echristo at gmail.com
Fri Aug 1 11:29:18 PDT 2014


For the record, a commit log that's a bit more descriptive is helpful.
Saying what your patch did, what it changed, how it changed it, etc is
very helpful.

-eric

On Fri, Aug 1, 2014 at 2:20 AM, Erik Eckstein <eeckstein at apple.com> wrote:
> Author: eeckstein
> Date: Fri Aug  1 04:20:42 2014
> New Revision: 214494
>
> URL: http://llvm.org/viewvc/llvm-project?rev=214494&view=rev
> Log:
> SLPVectorizer: improved scheduling algorithm.
>
> Added:
>     llvm/trunk/test/Transforms/SLPVectorizer/X86/scheduling.ll
> Modified:
>     llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp
>     llvm/trunk/test/Transforms/SLPVectorizer/X86/crash_vectorizeTree.ll
>     llvm/trunk/test/Transforms/SLPVectorizer/X86/in-tree-user.ll
>
> Modified: llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp?rev=214494&r1=214493&r2=214494&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp (original)
> +++ llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp Fri Aug  1 04:20:42 2014
> @@ -43,6 +43,7 @@
>  #include "llvm/Transforms/Utils/VectorUtils.h"
>  #include <algorithm>
>  #include <map>
> +#include <memory>
>
>  using namespace llvm;
>
> @@ -71,53 +72,6 @@ static const unsigned MinVecRegSize = 12
>
>  static const unsigned RecursionMaxDepth = 12;
>
> -/// A helper class for numbering instructions in multiple blocks.
> -/// Numbers start at zero for each basic block.
> -struct BlockNumbering {
> -
> -  BlockNumbering(BasicBlock *Bb) : BB(Bb), Valid(false) {}
> -
> -  void numberInstructions() {
> -    unsigned Loc = 0;
> -    InstrIdx.clear();
> -    InstrVec.clear();
> -    // Number the instructions in the block.
> -    for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) {
> -      InstrIdx[it] = Loc++;
> -      InstrVec.push_back(it);
> -      assert(InstrVec[InstrIdx[it]] == it && "Invalid allocation");
> -    }
> -    Valid = true;
> -  }
> -
> -  int getIndex(Instruction *I) {
> -    assert(I->getParent() == BB && "Invalid instruction");
> -    if (!Valid)
> -      numberInstructions();
> -    assert(InstrIdx.count(I) && "Unknown instruction");
> -    return InstrIdx[I];
> -  }
> -
> -  Instruction *getInstruction(unsigned loc) {
> -    if (!Valid)
> -      numberInstructions();
> -    assert(InstrVec.size() > loc && "Invalid Index");
> -    return InstrVec[loc];
> -  }
> -
> -  void forget() { Valid = false; }
> -
> -private:
> -  /// The block we are numbering.
> -  BasicBlock *BB;
> -  /// Is the block numbered.
> -  bool Valid;
> -  /// Maps instructions to numbers and back.
> -  SmallDenseMap<Instruction *, int> InstrIdx;
> -  /// Maps integers to Instructions.
> -  SmallVector<Instruction *, 32> InstrVec;
> -};
> -
>  /// \returns the parent basic block if all of the instructions in \p VL
>  /// are in the same block or null otherwise.
>  static BasicBlock *getSameBlock(ArrayRef<Value *> VL) {
> @@ -422,9 +376,12 @@ public:
>      ScalarToTreeEntry.clear();
>      MustGather.clear();
>      ExternalUses.clear();
> -    MemBarrierIgnoreList.clear();
>      NumLoadsWantToKeepOrder = 0;
>      NumLoadsWantToChangeOrder = 0;
> +    for (auto &Iter : BlocksSchedules) {
> +      BlockScheduling *BS = Iter.second.get();
> +      BS->clear();
> +    }
>    }
>
>    /// \returns true if the memory operations A and B are consecutive.
> @@ -474,20 +431,6 @@ private:
>    /// roots. This method calculates the cost of extracting the values.
>    int getGatherCost(ArrayRef<Value *> VL);
>
> -  /// \returns the AA location that is being access by the instruction.
> -  AliasAnalysis::Location getLocation(Instruction *I);
> -
> -  /// \brief Checks if it is possible to sink an instruction from
> -  /// \p Src to \p Dst.
> -  /// \returns the pointer to the barrier instruction if we can't sink.
> -  Value *getSinkBarrier(Instruction *Src, Instruction *Dst);
> -
> -  /// \returns the index of the last instruction in the BB from \p VL.
> -  int getLastIndex(ArrayRef<Value *> VL);
> -
> -  /// \returns the Instruction in the bundle \p VL.
> -  Instruction *getLastInstruction(ArrayRef<Value *> VL);
> -
>    /// \brief Set the Builder insert point to one after the last instruction in
>    /// the bundle
>    void setInsertPointAfterBundle(ArrayRef<Value *> VL);
> @@ -500,7 +443,7 @@ private:
>    bool isFullyVectorizableTinyTree();
>
>    struct TreeEntry {
> -    TreeEntry() : Scalars(), VectorizedValue(nullptr), LastScalarIndex(0),
> +    TreeEntry() : Scalars(), VectorizedValue(nullptr),
>      NeedToGather(0) {}
>
>      /// \returns true if the scalars in VL are equal to this entry.
> @@ -515,9 +458,6 @@ private:
>      /// The Scalars are vectorized into this value. It is initialized to Null.
>      Value *VectorizedValue;
>
> -    /// The index in the basic block of the last scalar.
> -    int LastScalarIndex;
> -
>      /// Do we need to gather this sequence ?
>      bool NeedToGather;
>    };
> @@ -530,18 +470,16 @@ private:
>      Last->Scalars.insert(Last->Scalars.begin(), VL.begin(), VL.end());
>      Last->NeedToGather = !Vectorized;
>      if (Vectorized) {
> -      Last->LastScalarIndex = getLastIndex(VL);
>        for (int i = 0, e = VL.size(); i != e; ++i) {
>          assert(!ScalarToTreeEntry.count(VL[i]) && "Scalar already in tree!");
>          ScalarToTreeEntry[VL[i]] = idx;
>        }
>      } else {
> -      Last->LastScalarIndex = 0;
>        MustGather.insert(VL.begin(), VL.end());
>      }
>      return Last;
>    }
> -
> +
>    /// -- Vectorization State --
>    /// Holds all of the tree entries.
>    std::vector<TreeEntry> VectorizableTree;
> @@ -569,24 +507,304 @@ private:
>    /// This list holds pairs of (Internal Scalar : External User).
>    UserList ExternalUses;
>
> -  /// A list of instructions to ignore while sinking
> -  /// memory instructions. This map must be reset between runs of getCost.
> -  ValueSet MemBarrierIgnoreList;
> -
>    /// Holds all of the instructions that we gathered.
>    SetVector<Instruction *> GatherSeq;
>    /// A list of blocks that we are going to CSE.
>    SetVector<BasicBlock *> CSEBlocks;
>
> -  /// Numbers instructions in different blocks.
> -  DenseMap<BasicBlock *, BlockNumbering> BlocksNumbers;
> +  /// Contains all scheduling relevant data for an instruction.
> +  /// A ScheduleData either represents a single instruction or a member of an
> +  /// instruction bundle (= a group of instructions which is combined into a
> +  /// vector instruction).
> +  struct ScheduleData {
> +
> +    // The initial value for the dependency counters. It means that the
> +    // dependencies are not calculated yet.
> +    enum { InvalidDeps = -1 };
> +
> +    ScheduleData()
> +        : Inst(nullptr), FirstInBundle(nullptr), NextInBundle(nullptr),
> +          NextLoadStore(nullptr), SchedulingRegionID(0), SchedulingPriority(0),
> +          Dependencies(InvalidDeps), UnscheduledDeps(InvalidDeps),
> +          UnscheduledDepsInBundle(InvalidDeps), IsScheduled(false) {}
> +
> +    void init(int BlockSchedulingRegionID) {
> +      FirstInBundle = this;
> +      NextInBundle = nullptr;
> +      NextLoadStore = nullptr;
> +      IsScheduled = false;
> +      SchedulingRegionID = BlockSchedulingRegionID;
> +      UnscheduledDepsInBundle = UnscheduledDeps;
> +      clearDependencies();
> +    }
> +
> +    /// Returns true if the dependency information has been calculated.
> +    bool hasValidDependencies() const { return Dependencies != InvalidDeps; }
> +
> +    /// Returns true for single instructions and for bundle representatives
> +    /// (= the head of a bundle).
> +    bool isSchedulingEntity() const { return FirstInBundle == this; }
> +
> +    /// Returns true if it represents an instruction bundle and not only a
> +    /// single instruction.
> +    bool isPartOfBundle() const {
> +      return NextInBundle != nullptr || FirstInBundle != this;
> +    }
> +
> +    /// Returns true if it is ready for scheduling, i.e. it has no more
> +    /// unscheduled depending instructions/bundles.
> +    bool isReady() const {
> +      assert(isSchedulingEntity() &&
> +             "can't consider non-scheduling entity for ready list");
> +      return UnscheduledDepsInBundle == 0 && !IsScheduled;
> +    }
> +
> +    /// Modifies the number of unscheduled dependencies, also updating it for
> +    /// the whole bundle.
> +    int incrementUnscheduledDeps(int Incr) {
> +      UnscheduledDeps += Incr;
> +      return FirstInBundle->UnscheduledDepsInBundle += Incr;
> +    }
> +
> +    /// Sets the number of unscheduled dependencies to the number of
> +    /// dependencies.
> +    void resetUnscheduledDeps() {
> +      incrementUnscheduledDeps(Dependencies - UnscheduledDeps);
> +    }
> +
> +    /// Clears all dependency information.
> +    void clearDependencies() {
> +      Dependencies = InvalidDeps;
> +      resetUnscheduledDeps();
> +      MemoryDependencies.clear();
> +    }
> +
> +    void dump(raw_ostream &os) const {
> +      if (!isSchedulingEntity()) {
> +        os << "/ " << *Inst;
> +      } else if (NextInBundle) {
> +        os << '[' << *Inst;
> +        ScheduleData *SD = NextInBundle;
> +        while (SD) {
> +          os << ';' << *SD->Inst;
> +          SD = SD->NextInBundle;
> +        }
> +        os << ']';
> +      } else {
> +        os << *Inst;
> +      }
> +    }
>
> -  /// \brief Get the corresponding instruction numbering list for a given
> -  /// BasicBlock. The list is allocated lazily.
> -  BlockNumbering &getBlockNumbering(BasicBlock *BB) {
> -    auto I = BlocksNumbers.insert(std::make_pair(BB, BlockNumbering(BB)));
> -    return I.first->second;
> -  }
> +    Instruction *Inst;
> +
> +    /// Points to the head in an instruction bundle (and always to this for
> +    /// single instructions).
> +    ScheduleData *FirstInBundle;
> +
> +    /// Single linked list of all instructions in a bundle. Null if it is a
> +    /// single instruction.
> +    ScheduleData *NextInBundle;
> +
> +    /// Single linked list of all memory instructions (e.g. load, store, call)
> +    /// in the block - until the end of the scheduling region.
> +    ScheduleData *NextLoadStore;
> +
> +    /// The dependent memory instructions.
> +    /// This list is derived on demand in calculateDependencies().
> +    SmallVector<ScheduleData *, 4> MemoryDependencies;
> +
> +    /// This ScheduleData is in the current scheduling region if this matches
> +    /// the current SchedulingRegionID of BlockScheduling.
> +    int SchedulingRegionID;
> +
> +    /// Used for getting a "good" final ordering of instructions.
> +    int SchedulingPriority;
> +
> +    /// The number of dependencies. Constitutes of the number of users of the
> +    /// instruction plus the number of dependent memory instructions (if any).
> +    /// This value is calculated on demand.
> +    /// If InvalidDeps, the number of dependencies is not calculated yet.
> +    ///
> +    int Dependencies;
> +
> +    /// The number of dependencies minus the number of dependencies of scheduled
> +    /// instructions. As soon as this is zero, the instruction/bundle gets ready
> +    /// for scheduling.
> +    /// Note that this is negative as long as Dependencies is not calculated.
> +    int UnscheduledDeps;
> +
> +    /// The sum of UnscheduledDeps in a bundle. Equals to UnscheduledDeps for
> +    /// single instructions.
> +    int UnscheduledDepsInBundle;
> +
> +    /// True if this instruction is scheduled (or considered as scheduled in the
> +    /// dry-run).
> +    bool IsScheduled;
> +  };
> +
> +  friend raw_ostream &operator<<(raw_ostream &os,
> +                                 const BoUpSLP::ScheduleData &SD);
> +
> +  /// Contains all scheduling data for a basic block.
> +  ///
> +  struct BlockScheduling {
> +
> +    BlockScheduling(BasicBlock *BB)
> +        : BB(BB), ChunkSize(BB->size()), ChunkPos(ChunkSize),
> +          ScheduleStart(nullptr), ScheduleEnd(nullptr),
> +          FirstLoadStoreInRegion(nullptr), LastLoadStoreInRegion(nullptr),
> +          // Make sure that the initial SchedulingRegionID is greater than the
> +          // initial SchedulingRegionID in ScheduleData (which is 0).
> +          SchedulingRegionID(1) {}
> +
> +    void clear() {
> +      ReadyInsts.clear();
> +      ScheduleStart = nullptr;
> +      ScheduleEnd = nullptr;
> +      FirstLoadStoreInRegion = nullptr;
> +      LastLoadStoreInRegion = nullptr;
> +
> +      // Make a new scheduling region, i.e. all existing ScheduleData is not
> +      // in the new region yet.
> +      ++SchedulingRegionID;
> +    }
> +
> +    ScheduleData *getScheduleData(Value *V) {
> +      ScheduleData *SD = ScheduleDataMap[V];
> +      if (SD && SD->SchedulingRegionID == SchedulingRegionID)
> +        return SD;
> +      return nullptr;
> +    }
> +
> +    bool isInSchedulingRegion(ScheduleData *SD) {
> +      return SD->SchedulingRegionID == SchedulingRegionID;
> +    }
> +
> +    /// Marks an instruction as scheduled and puts all dependent ready
> +    /// instructions into the ready-list.
> +    template <typename ReadyListType>
> +    void schedule(ScheduleData *SD, ReadyListType &ReadyList) {
> +      SD->IsScheduled = true;
> +      DEBUG(dbgs() << "SLP:   schedule " << *SD << "\n");
> +
> +      ScheduleData *BundleMember = SD;
> +      while (BundleMember) {
> +        // Handle the def-use chain dependencies.
> +        for (Use &U : BundleMember->Inst->operands()) {
> +          ScheduleData *OpDef = getScheduleData(U.get());
> +          if (OpDef && OpDef->hasValidDependencies() &&
> +              OpDef->incrementUnscheduledDeps(-1) == 0) {
> +            // There are no more unscheduled dependencies after decrementing,
> +            // so we can put the dependent instruction into the ready list.
> +            ScheduleData *DepBundle = OpDef->FirstInBundle;
> +            assert(!DepBundle->IsScheduled &&
> +                   "already scheduled bundle gets ready");
> +            ReadyList.insert(DepBundle);
> +            DEBUG(dbgs() << "SLP:    gets ready (def): " << *DepBundle << "\n");
> +          }
> +        }
> +        // Handle the memory dependencies.
> +        for (ScheduleData *MemoryDepSD : BundleMember->MemoryDependencies) {
> +          if (MemoryDepSD->incrementUnscheduledDeps(-1) == 0) {
> +            // There are no more unscheduled dependencies after decrementing,
> +            // so we can put the dependent instruction into the ready list.
> +            ScheduleData *DepBundle = MemoryDepSD->FirstInBundle;
> +            assert(!DepBundle->IsScheduled &&
> +                   "already scheduled bundle gets ready");
> +            ReadyList.insert(DepBundle);
> +            DEBUG(dbgs() << "SLP:    gets ready (mem): " << *DepBundle << "\n");
> +          }
> +        }
> +        BundleMember = BundleMember->NextInBundle;
> +      }
> +    }
> +
> +    /// Put all instructions into the ReadyList which are ready for scheduling.
> +    template <typename ReadyListType>
> +    void initialFillReadyList(ReadyListType &ReadyList) {
> +      for (auto *I = ScheduleStart; I != ScheduleEnd; I = I->getNextNode()) {
> +        ScheduleData *SD = getScheduleData(I);
> +        if (SD->isSchedulingEntity() && SD->isReady()) {
> +          ReadyList.insert(SD);
> +          DEBUG(dbgs() << "SLP:    initially in ready list: " << *I << "\n");
> +        }
> +      }
> +    }
> +
> +    /// Checks if a bundle of instructions can be scheduled, i.e. has no
> +    /// cyclic dependencies. This is only a dry-run, no instructions are
> +    /// actually moved at this stage.
> +    bool tryScheduleBundle(ArrayRef<Value *> VL, AliasAnalysis *AA);
> +
> +    /// Un-bundles a group of instructions.
> +    void cancelScheduling(ArrayRef<Value *> VL);
> +
> +    /// Extends the scheduling region so that V is inside the region.
> +    void extendSchedulingRegion(Value *V);
> +
> +    /// Initialize the ScheduleData structures for new instructions in the
> +    /// scheduling region.
> +    void initScheduleData(Instruction *FromI, Instruction *ToI,
> +                          ScheduleData *PrevLoadStore,
> +                          ScheduleData *NextLoadStore);
> +
> +    /// Updates the dependency information of a bundle and of all instructions/
> +    /// bundles which depend on the original bundle.
> +    void calculateDependencies(ScheduleData *SD, bool InsertInReadyList,
> +                               AliasAnalysis *AA);
> +
> +    /// Sets all instruction in the scheduling region to un-scheduled.
> +    void resetSchedule();
> +
> +    BasicBlock *BB;
> +
> +    /// Simple memory allocation for ScheduleData.
> +    std::vector<std::unique_ptr<ScheduleData[]>> ScheduleDataChunks;
> +
> +    /// The size of a ScheduleData array in ScheduleDataChunks.
> +    int ChunkSize;
> +
> +    /// The allocator position in the current chunk, which is the last entry
> +    /// of ScheduleDataChunks.
> +    int ChunkPos;
> +
> +    /// Attaches ScheduleData to Instruction.
> +    /// Note that the mapping survives during all vectorization iterations, i.e.
> +    /// ScheduleData structures are recycled.
> +    DenseMap<Value *, ScheduleData *> ScheduleDataMap;
> +
> +    struct ReadyList : SmallVector<ScheduleData *, 8> {
> +      void insert(ScheduleData *SD) { push_back(SD); }
> +    };
> +
> +    /// The ready-list for scheduling (only used for the dry-run).
> +    ReadyList ReadyInsts;
> +
> +    /// The first instruction of the scheduling region.
> +    Instruction *ScheduleStart;
> +
> +    /// The first instruction _after_ the scheduling region.
> +    Instruction *ScheduleEnd;
> +
> +    /// The first memory accessing instruction in the scheduling region
> +    /// (can be null).
> +    ScheduleData *FirstLoadStoreInRegion;
> +
> +    /// The last memory accessing instruction in the scheduling region
> +    /// (can be null).
> +    ScheduleData *LastLoadStoreInRegion;
> +
> +    /// The ID of the scheduling region. For a new vectorization iteration this
> +    /// is incremented which "removes" all ScheduleData from the region.
> +    int SchedulingRegionID;
> +  };
> +
> +  /// Attaches the BlockScheduling structures to basic blocks.
> +  DenseMap<BasicBlock *, std::unique_ptr<BlockScheduling>> BlocksSchedules;
> +
> +  /// Performs the "real" scheduling. Done before vectorization is actually
> +  /// performed in a basic block.
> +  void scheduleBlock(BasicBlock *BB);
>
>    /// List of users to ignore during scheduling and that don't need extracting.
>    ArrayRef<Value *> UserIgnoreList;
> @@ -609,6 +827,11 @@ private:
>    /// Instruction builder to construct the vectorized tree.
>    IRBuilder<> Builder;
>  };
> +
> +raw_ostream &operator<<(raw_ostream &os, const BoUpSLP::ScheduleData &SD) {
> +  SD.dump(os);
> +  return os;
> +}
>
>  void BoUpSLP::buildTree(ArrayRef<Value *> Roots,
>                          ArrayRef<Value *> UserIgnoreLst) {
> @@ -743,69 +966,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>    // Check that all of the users of the scalars that we want to vectorize are
>    // schedulable.
>    Instruction *VL0 = cast<Instruction>(VL[0]);
> -  int MyLastIndex = getLastIndex(VL);
>    BasicBlock *BB = cast<Instruction>(VL0)->getParent();
>
> -  for (unsigned i = 0, e = VL.size(); i != e; ++i) {
> -    Instruction *Scalar = cast<Instruction>(VL[i]);
> -    DEBUG(dbgs() << "SLP: Checking users of  " << *Scalar << ". \n");
> -    for (User *U : Scalar->users()) {
> -      DEBUG(dbgs() << "SLP: \tUser " << *U << ". \n");
> -      Instruction *UI = dyn_cast<Instruction>(U);
> -      if (!UI) {
> -        DEBUG(dbgs() << "SLP: Gathering due unknown user. \n");
> -        newTreeEntry(VL, false);
> -        return;
> -      }
> -
> -      // We don't care if the user is in a different basic block.
> -      BasicBlock *UserBlock = UI->getParent();
> -      if (UserBlock != BB) {
> -        DEBUG(dbgs() << "SLP: User from a different basic block "
> -              << *UI << ". \n");
> -        continue;
> -      }
> -
> -      // If this is a PHINode within this basic block then we can place the
> -      // extract wherever we want.
> -      if (isa<PHINode>(*UI)) {
> -        DEBUG(dbgs() << "SLP: \tWe can schedule PHIs:" << *UI << ". \n");
> -        continue;
> -      }
> -
> -      // Check if this is a safe in-tree user.
> -      if (ScalarToTreeEntry.count(UI)) {
> -        int Idx = ScalarToTreeEntry[UI];
> -        int VecLocation = VectorizableTree[Idx].LastScalarIndex;
> -        if (VecLocation <= MyLastIndex) {
> -          DEBUG(dbgs() << "SLP: Gathering due to unschedulable vector. \n");
> -          newTreeEntry(VL, false);
> -          return;
> -        }
> -        DEBUG(dbgs() << "SLP: In-tree user (" << *UI << ") at #" <<
> -              VecLocation << " vector value (" << *Scalar << ") at #"
> -              << MyLastIndex << ".\n");
> -        continue;
> -      }
> -
> -      // Ignore users in the user ignore list.
> -      if (std::find(UserIgnoreList.begin(), UserIgnoreList.end(), UI) !=
> -          UserIgnoreList.end())
> -        continue;
> -
> -      // Make sure that we can schedule this unknown user.
> -      BlockNumbering &BN = getBlockNumbering(BB);
> -      int UserIndex = BN.getIndex(UI);
> -      if (UserIndex < MyLastIndex) {
> -
> -        DEBUG(dbgs() << "SLP: Can't schedule extractelement for "
> -              << *UI << ". \n");
> -        newTreeEntry(VL, false);
> -        return;
> -      }
> -    }
> -  }
> -
>    // Check that every instructions appears once in this bundle.
>    for (unsigned i = 0, e = VL.size(); i < e; ++i)
>      for (unsigned j = i+1; j < e; ++j)
> @@ -815,39 +977,20 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>          return;
>        }
>
> -  // Check that instructions in this bundle don't reference other instructions.
> -  // The runtime of this check is O(N * N-1 * uses(N)) and a typical N is 4.
> -  for (unsigned i = 0, e = VL.size(); i < e; ++i) {
> -    for (User *U : VL[i]->users()) {
> -      for (unsigned j = 0; j < e; ++j) {
> -        if (i != j && U == VL[j]) {
> -          DEBUG(dbgs() << "SLP: Intra-bundle dependencies!" << *U << ". \n");
> -          newTreeEntry(VL, false);
> -          return;
> -        }
> -      }
> -    }
> +  auto &BSRef = BlocksSchedules[BB];
> +  if (!BSRef) {
> +    BSRef = llvm::make_unique<BlockScheduling>(BB);
> +  }
> +  BlockScheduling &BS = *BSRef.get();
> +
> +  if (!BS.tryScheduleBundle(VL, AA)) {
> +    DEBUG(dbgs() << "SLP: We are not able to schedule this bundle!\n");
> +    BS.cancelScheduling(VL);
> +    newTreeEntry(VL, false);
> +    return;
>    }
> -
>    DEBUG(dbgs() << "SLP: We are able to schedule this bundle.\n");
>
> -  // Check if it is safe to sink the loads or the stores.
> -  if (Opcode == Instruction::Load || Opcode == Instruction::Store) {
> -    Instruction *Last = getLastInstruction(VL);
> -
> -    for (unsigned i = 0, e = VL.size(); i < e; ++i) {
> -      if (VL[i] == Last)
> -        continue;
> -      Value *Barrier = getSinkBarrier(cast<Instruction>(VL[i]), Last);
> -      if (Barrier) {
> -        DEBUG(dbgs() << "SLP: Can't sink " << *VL[i] << "\n down to " << *Last
> -              << "\n because of " << *Barrier << ".  Gathering.\n");
> -        newTreeEntry(VL, false);
> -        return;
> -      }
> -    }
> -  }
> -
>    switch (Opcode) {
>      case Instruction::PHI: {
>        PHINode *PH = dyn_cast<PHINode>(VL0);
> @@ -859,6 +1002,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>                cast<PHINode>(VL[j])->getIncomingValueForBlock(PH->getIncomingBlock(i)));
>            if (Term) {
>              DEBUG(dbgs() << "SLP: Need to swizzle PHINodes (TerminatorInst use).\n");
> +            BS.cancelScheduling(VL);
>              newTreeEntry(VL, false);
>              return;
>            }
> @@ -882,6 +1026,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        bool Reuse = CanReuseExtract(VL);
>        if (Reuse) {
>          DEBUG(dbgs() << "SLP: Reusing extract sequence.\n");
> +      } else {
> +        BS.cancelScheduling(VL);
>        }
>        newTreeEntry(VL, Reuse);
>        return;
> @@ -891,6 +1037,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        for (unsigned i = 0, e = VL.size() - 1; i < e; ++i) {
>          LoadInst *L = cast<LoadInst>(VL[i]);
>          if (!L->isSimple()) {
> +          BS.cancelScheduling(VL);
>            newTreeEntry(VL, false);
>            DEBUG(dbgs() << "SLP: Gathering non-simple loads.\n");
>            return;
> @@ -899,6 +1046,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>            if (VL.size() == 2 && isConsecutiveAccess(VL[1], VL[0])) {
>              ++NumLoadsWantToChangeOrder;
>            }
> +          BS.cancelScheduling(VL);
>            newTreeEntry(VL, false);
>            DEBUG(dbgs() << "SLP: Gathering non-consecutive loads.\n");
>            return;
> @@ -925,6 +1073,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        for (unsigned i = 0; i < VL.size(); ++i) {
>          Type *Ty = cast<Instruction>(VL[i])->getOperand(0)->getType();
>          if (Ty != SrcTy || Ty->isAggregateType() || Ty->isVectorTy()) {
> +          BS.cancelScheduling(VL);
>            newTreeEntry(VL, false);
>            DEBUG(dbgs() << "SLP: Gathering casts with different src types.\n");
>            return;
> @@ -952,6 +1101,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>          CmpInst *Cmp = cast<CmpInst>(VL[i]);
>          if (Cmp->getPredicate() != P0 ||
>              Cmp->getOperand(0)->getType() != ComparedTy) {
> +          BS.cancelScheduling(VL);
>            newTreeEntry(VL, false);
>            DEBUG(dbgs() << "SLP: Gathering cmp with different predicate.\n");
>            return;
> @@ -998,20 +1148,8 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        if (isa<BinaryOperator>(VL0) && VL0->isCommutative()) {
>          ValueList Left, Right;
>          reorderInputsAccordingToOpcode(VL, Left, Right);
> -        BasicBlock *LeftBB = getSameBlock(Left);
> -        BasicBlock *RightBB = getSameBlock(Right);
> -        // If we have common uses on separate paths in the tree make sure we
> -        // process the one with greater common depth first.
> -        // We can use block numbering to determine the subtree traversal as
> -        // earler user has to come in between the common use and the later user.
> -        if (LeftBB && RightBB && LeftBB == RightBB &&
> -            getLastIndex(Right) > getLastIndex(Left)) {
> -          buildTree_rec(Right, Depth + 1);
> -          buildTree_rec(Left, Depth + 1);
> -        } else {
> -          buildTree_rec(Left, Depth + 1);
> -          buildTree_rec(Right, Depth + 1);
> -        }
> +        buildTree_rec(Left, Depth + 1);
> +        buildTree_rec(Right, Depth + 1);
>          return;
>        }
>
> @@ -1030,6 +1168,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        for (unsigned j = 0; j < VL.size(); ++j) {
>          if (cast<Instruction>(VL[j])->getNumOperands() != 2) {
>            DEBUG(dbgs() << "SLP: not-vectorizable GEP (nested indexes).\n");
> +          BS.cancelScheduling(VL);
>            newTreeEntry(VL, false);
>            return;
>          }
> @@ -1042,6 +1181,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>          Type *CurTy = cast<Instruction>(VL[j])->getOperand(0)->getType();
>          if (Ty0 != CurTy) {
>            DEBUG(dbgs() << "SLP: not-vectorizable GEP (different types).\n");
> +          BS.cancelScheduling(VL);
>            newTreeEntry(VL, false);
>            return;
>          }
> @@ -1053,6 +1193,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>          if (!isa<ConstantInt>(Op)) {
>            DEBUG(
>                dbgs() << "SLP: not-vectorizable GEP (non-constant indexes).\n");
> +          BS.cancelScheduling(VL);
>            newTreeEntry(VL, false);
>            return;
>          }
> @@ -1074,6 +1215,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        // Check if the stores are consecutive or of we need to swizzle them.
>        for (unsigned i = 0, e = VL.size() - 1; i < e; ++i)
>          if (!isConsecutiveAccess(VL[i], VL[i + 1])) {
> +          BS.cancelScheduling(VL);
>            newTreeEntry(VL, false);
>            DEBUG(dbgs() << "SLP: Non-consecutive store.\n");
>            return;
> @@ -1086,8 +1228,6 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        for (unsigned j = 0; j < VL.size(); ++j)
>          Operands.push_back(cast<Instruction>(VL[j])->getOperand(0));
>
> -      // We can ignore these values because we are sinking them down.
> -      MemBarrierIgnoreList.insert(VL.begin(), VL.end());
>        buildTree_rec(Operands, Depth + 1);
>        return;
>      }
> @@ -1098,6 +1238,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        // represented by an intrinsic call
>        Intrinsic::ID ID = getIntrinsicIDForCall(CI, TLI);
>        if (!isTriviallyVectorizable(ID)) {
> +        BS.cancelScheduling(VL);
>          newTreeEntry(VL, false);
>          DEBUG(dbgs() << "SLP: Non-vectorizable call.\n");
>          return;
> @@ -1110,6 +1251,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>          CallInst *CI2 = dyn_cast<CallInst>(VL[i]);
>          if (!CI2 || CI2->getCalledFunction() != Int ||
>              getIntrinsicIDForCall(CI2, TLI) != ID) {
> +          BS.cancelScheduling(VL);
>            newTreeEntry(VL, false);
>            DEBUG(dbgs() << "SLP: mismatched calls:" << *CI << "!=" << *VL[i]
>                         << "\n");
> @@ -1120,6 +1262,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>          if (hasVectorInstrinsicScalarOpd(ID, 1)) {
>            Value *A1J = CI2->getArgOperand(1);
>            if (A1I != A1J) {
> +            BS.cancelScheduling(VL);
>              newTreeEntry(VL, false);
>              DEBUG(dbgs() << "SLP: mismatched arguments in call:" << *CI
>                           << " argument "<< A1I<<"!=" << A1J
> @@ -1145,6 +1288,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        // If this is not an alternate sequence of opcode like add-sub
>        // then do not vectorize this instruction.
>        if (!isAltShuffle) {
> +        BS.cancelScheduling(VL);
>          newTreeEntry(VL, false);
>          DEBUG(dbgs() << "SLP: ShuffleVector are not vectorized.\n");
>          return;
> @@ -1162,6 +1306,7 @@ void BoUpSLP::buildTree_rec(ArrayRef<Val
>        return;
>      }
>      default:
> +      BS.cancelScheduling(VL);
>        newTreeEntry(VL, false);
>        DEBUG(dbgs() << "SLP: Gathering unknown instruction.\n");
>        return;
> @@ -1450,14 +1595,6 @@ int BoUpSLP::getGatherCost(ArrayRef<Valu
>    return getGatherCost(VecTy);
>  }
>
> -AliasAnalysis::Location BoUpSLP::getLocation(Instruction *I) {
> -  if (StoreInst *SI = dyn_cast<StoreInst>(I))
> -    return AA->getLocation(SI);
> -  if (LoadInst *LI = dyn_cast<LoadInst>(I))
> -    return AA->getLocation(LI);
> -  return AliasAnalysis::Location();
> -}
> -
>  Value *BoUpSLP::getPointerOperand(Value *I) {
>    if (LoadInst *LI = dyn_cast<LoadInst>(I))
>      return LI->getPointerOperand();
> @@ -1515,59 +1652,9 @@ bool BoUpSLP::isConsecutiveAccess(Value
>    return X == PtrSCEVB;
>  }
>
> -Value *BoUpSLP::getSinkBarrier(Instruction *Src, Instruction *Dst) {
> -  assert(Src->getParent() == Dst->getParent() && "Not the same BB");
> -  BasicBlock::iterator I = Src, E = Dst;
> -  /// Scan all of the instruction from SRC to DST and check if
> -  /// the source may alias.
> -  for (++I; I != E; ++I) {
> -    // Ignore store instructions that are marked as 'ignore'.
> -    if (MemBarrierIgnoreList.count(I))
> -      continue;
> -    if (Src->mayWriteToMemory()) /* Write */ {
> -      if (!I->mayReadOrWriteMemory())
> -        continue;
> -    } else /* Read */ {
> -      if (!I->mayWriteToMemory())
> -        continue;
> -    }
> -    AliasAnalysis::Location A = getLocation(&*I);
> -    AliasAnalysis::Location B = getLocation(Src);
> -
> -    if (!A.Ptr || !B.Ptr || AA->alias(A, B))
> -      return I;
> -  }
> -  return nullptr;
> -}
> -
> -int BoUpSLP::getLastIndex(ArrayRef<Value *> VL) {
> -  BasicBlock *BB = cast<Instruction>(VL[0])->getParent();
> -  assert(BB == getSameBlock(VL) && "Invalid block");
> -  BlockNumbering &BN = getBlockNumbering(BB);
> -
> -  int MaxIdx = BN.getIndex(BB->getFirstNonPHI());
> -  for (unsigned i = 0, e = VL.size(); i < e; ++i)
> -    MaxIdx = std::max(MaxIdx, BN.getIndex(cast<Instruction>(VL[i])));
> -  return MaxIdx;
> -}
> -
> -Instruction *BoUpSLP::getLastInstruction(ArrayRef<Value *> VL) {
> -  BasicBlock *BB = cast<Instruction>(VL[0])->getParent();
> -  assert(BB == getSameBlock(VL) && "Invalid block");
> -  BlockNumbering &BN = getBlockNumbering(BB);
> -
> -  int MaxIdx = BN.getIndex(cast<Instruction>(VL[0]));
> -  for (unsigned i = 1, e = VL.size(); i < e; ++i)
> -    MaxIdx = std::max(MaxIdx, BN.getIndex(cast<Instruction>(VL[i])));
> -  Instruction *I = BN.getInstruction(MaxIdx);
> -  assert(I && "bad location");
> -  return I;
> -}
> -
>  void BoUpSLP::setInsertPointAfterBundle(ArrayRef<Value *> VL) {
>    Instruction *VL0 = cast<Instruction>(VL[0]);
> -  Instruction *LastInst = getLastInstruction(VL);
> -  BasicBlock::iterator NextInst = LastInst;
> +  BasicBlock::iterator NextInst = VL0;
>    ++NextInst;
>    Builder.SetInsertPoint(VL0->getParent(), NextInst);
>    Builder.SetCurrentDebugLocation(VL0->getDebugLoc());
> @@ -1650,6 +1737,9 @@ Value *BoUpSLP::vectorizeTree(TreeEntry
>      setInsertPointAfterBundle(E->Scalars);
>      return Gather(E->Scalars, VecTy);
>    }
> +  BasicBlock *BB = VL0->getParent();
> +  scheduleBlock(BB);
> +
>    unsigned Opcode = getSameOpcode(E->Scalars);
>
>    switch (Opcode) {
> @@ -2070,9 +2160,6 @@ Value *BoUpSLP::vectorizeTree() {
>      }
>    }
>
> -  for (auto &BN : BlocksNumbers)
> -    BN.second.forget();
> -
>    Builder.ClearInsertionPoint();
>
>    return VectorizableTree[0].VectorizedValue;
> @@ -2166,6 +2253,363 @@ void BoUpSLP::optimizeGatherSequence() {
>    GatherSeq.clear();
>  }
>
> +// Groups the instructions to a bundle (which is then a single scheduling entity)
> +// and schedules instructions until the bundle gets ready.
> +bool BoUpSLP::BlockScheduling::tryScheduleBundle(ArrayRef<Value *> VL,
> +                                                 AliasAnalysis *AA) {
> +  if (isa<PHINode>(VL[0]))
> +    return true;
> +
> +  // Initialize the instruction bundle.
> +  Instruction *OldScheduleEnd = ScheduleEnd;
> +  ScheduleData *PrevInBundle = nullptr;
> +  ScheduleData *Bundle = nullptr;
> +  bool ReSchedule = false;
> +  DEBUG(dbgs() << "SLP:  bundle: " << *VL[0] << "\n");
> +  for (Value *V : VL) {
> +    extendSchedulingRegion(V);
> +    ScheduleData *BundleMember = getScheduleData(V);
> +    assert(BundleMember &&
> +           "no ScheduleData for bundle member (maybe not in same basic block)");
> +    if (BundleMember->IsScheduled) {
> +      // A bundle member was scheduled as single instruction before and now
> +      // needs to be scheduled as part of the bundle. We just get rid of the
> +      // existing schedule.
> +      DEBUG(dbgs() << "SLP:  reset schedule because " << *BundleMember
> +                   << " was already scheduled\n");
> +      ReSchedule = true;
> +    }
> +    assert(BundleMember->isSchedulingEntity() &&
> +           "bundle member already part of other bundle");
> +    if (PrevInBundle) {
> +      PrevInBundle->NextInBundle = BundleMember;
> +    } else {
> +      Bundle = BundleMember;
> +    }
> +    BundleMember->UnscheduledDepsInBundle = 0;
> +    Bundle->UnscheduledDepsInBundle += BundleMember->UnscheduledDeps;
> +
> +    // Group the instructions to a bundle.
> +    BundleMember->FirstInBundle = Bundle;
> +    PrevInBundle = BundleMember;
> +  }
> +  if (ScheduleEnd != OldScheduleEnd) {
> +    // The scheduling region got new instructions at the lower end (or it is a
> +    // new region for the first bundle). This makes it necessary to
> +    // recalculate all dependencies.
> +    // It is seldom that this needs to be done a second time after adding the
> +    // initial bundle to the region.
> +    for (auto *I = ScheduleStart; I != ScheduleEnd; I = I->getNextNode()) {
> +      ScheduleData *SD = getScheduleData(I);
> +      SD->clearDependencies();
> +    }
> +    ReSchedule = true;
> +  }
> +  if (ReSchedule) {
> +    resetSchedule();
> +    initialFillReadyList(ReadyInsts);
> +  }
> +
> +  DEBUG(dbgs() << "SLP: try schedule bundle " << *Bundle << " in block "
> +               << BB->getName() << "\n");
> +
> +  calculateDependencies(Bundle, true, AA);
> +
> +  // Now try to schedule the new bundle. As soon as the bundle is "ready" it
> +  // means that there are no cyclic dependencies and we can schedule it.
> +  // Note that's important that we don't "schedule" the bundle yet (see
> +  // cancelScheduling).
> +  while (!Bundle->isReady() && !ReadyInsts.empty()) {
> +
> +    ScheduleData *pickedSD = ReadyInsts.back();
> +    ReadyInsts.pop_back();
> +
> +    if (pickedSD->isSchedulingEntity() && pickedSD->isReady()) {
> +      schedule(pickedSD, ReadyInsts);
> +    }
> +  }
> +  return Bundle->isReady();
> +}
> +
> +void BoUpSLP::BlockScheduling::cancelScheduling(ArrayRef<Value *> VL) {
> +  if (isa<PHINode>(VL[0]))
> +    return;
> +
> +  ScheduleData *Bundle = getScheduleData(VL[0]);
> +  DEBUG(dbgs() << "SLP:  cancel scheduling of " << *Bundle << "\n");
> +  assert(!Bundle->IsScheduled &&
> +         "Can't cancel bundle which is already scheduled");
> +  assert(Bundle->isSchedulingEntity() && Bundle->isPartOfBundle() &&
> +         "tried to unbundle something which is not a bundle");
> +
> +  // Un-bundle: make single instructions out of the bundle.
> +  ScheduleData *BundleMember = Bundle;
> +  while (BundleMember) {
> +    assert(BundleMember->FirstInBundle == Bundle && "corrupt bundle links");
> +    BundleMember->FirstInBundle = BundleMember;
> +    ScheduleData *Next = BundleMember->NextInBundle;
> +    BundleMember->NextInBundle = nullptr;
> +    BundleMember->UnscheduledDepsInBundle = BundleMember->UnscheduledDeps;
> +    if (BundleMember->UnscheduledDepsInBundle == 0) {
> +      ReadyInsts.insert(BundleMember);
> +    }
> +    BundleMember = Next;
> +  }
> +}
> +
> +void BoUpSLP::BlockScheduling::extendSchedulingRegion(Value *V) {
> +  if (getScheduleData(V))
> +    return;
> +  Instruction *I = dyn_cast<Instruction>(V);
> +  assert(I && "bundle member must be an instruction");
> +  assert(!isa<PHINode>(I) && "phi nodes don't need to be scheduled");
> +  if (!ScheduleStart) {
> +    // It's the first instruction in the new region.
> +    initScheduleData(I, I->getNextNode(), nullptr, nullptr);
> +    ScheduleStart = I;
> +    ScheduleEnd = I->getNextNode();
> +    assert(ScheduleEnd && "tried to vectorize a TerminatorInst?");
> +    DEBUG(dbgs() << "SLP:  initialize schedule region to " << *I << "\n");
> +    return;
> +  }
> +  // Search up and down at the same time, because we don't know if the new
> +  // instruction is above or below the existing scheduling region.
> +  BasicBlock::reverse_iterator UpIter(ScheduleStart);
> +  BasicBlock::reverse_iterator UpperEnd = BB->rend();
> +  BasicBlock::iterator DownIter(ScheduleEnd);
> +  BasicBlock::iterator LowerEnd = BB->end();
> +  for (;;) {
> +    if (UpIter != UpperEnd) {
> +      if (&*UpIter == I) {
> +        initScheduleData(I, ScheduleStart, nullptr, FirstLoadStoreInRegion);
> +        ScheduleStart = I;
> +        DEBUG(dbgs() << "SLP:  extend schedule region start to " << *I << "\n");
> +        return;
> +      }
> +      UpIter++;
> +    }
> +    if (DownIter != LowerEnd) {
> +      if (&*DownIter == I) {
> +        initScheduleData(ScheduleEnd, I->getNextNode(), LastLoadStoreInRegion,
> +                         nullptr);
> +        ScheduleEnd = I->getNextNode();
> +        assert(ScheduleEnd && "tried to vectorize a TerminatorInst?");
> +        DEBUG(dbgs() << "SLP:  extend schedule region end to " << *I << "\n");
> +        return;
> +      }
> +      DownIter++;
> +    }
> +    assert((UpIter != UpperEnd || DownIter != LowerEnd) &&
> +           "instruction not found in block");
> +  }
> +}
> +
> +void BoUpSLP::BlockScheduling::initScheduleData(Instruction *FromI,
> +                                                Instruction *ToI,
> +                                                ScheduleData *PrevLoadStore,
> +                                                ScheduleData *NextLoadStore) {
> +  ScheduleData *CurrentLoadStore = PrevLoadStore;
> +  for (Instruction *I = FromI; I != ToI; I = I->getNextNode()) {
> +    ScheduleData *SD = ScheduleDataMap[I];
> +    if (!SD) {
> +      // Allocate a new ScheduleData for the instruction.
> +      if (ChunkPos >= ChunkSize) {
> +        ScheduleDataChunks.push_back(
> +            llvm::make_unique<ScheduleData[]>(ChunkSize));
> +        ChunkPos = 0;
> +      }
> +      SD = &(ScheduleDataChunks.back()[ChunkPos++]);
> +      ScheduleDataMap[I] = SD;
> +      SD->Inst = I;
> +    }
> +    assert(!isInSchedulingRegion(SD) &&
> +           "new ScheduleData already in scheduling region");
> +    SD->init(SchedulingRegionID);
> +
> +    if (I->mayReadOrWriteMemory()) {
> +      // Update the linked list of memory accessing instructions.
> +      if (CurrentLoadStore) {
> +        CurrentLoadStore->NextLoadStore = SD;
> +      } else {
> +        FirstLoadStoreInRegion = SD;
> +      }
> +      CurrentLoadStore = SD;
> +    }
> +  }
> +  if (NextLoadStore) {
> +    if (CurrentLoadStore)
> +      CurrentLoadStore->NextLoadStore = NextLoadStore;
> +  } else {
> +    LastLoadStoreInRegion = CurrentLoadStore;
> +  }
> +}
> +
> +/// \returns the AA location that is being access by the instruction.
> +static AliasAnalysis::Location getLocation(Instruction *I, AliasAnalysis *AA) {
> +  if (StoreInst *SI = dyn_cast<StoreInst>(I))
> +    return AA->getLocation(SI);
> +  if (LoadInst *LI = dyn_cast<LoadInst>(I))
> +    return AA->getLocation(LI);
> +  return AliasAnalysis::Location();
> +}
> +
> +void BoUpSLP::BlockScheduling::calculateDependencies(ScheduleData *SD,
> +                                                     bool InsertInReadyList,
> +                                                     AliasAnalysis *AA) {
> +  assert(SD->isSchedulingEntity());
> +
> +  SmallVector<ScheduleData *, 10> WorkList;
> +  WorkList.push_back(SD);
> +
> +  while (!WorkList.empty()) {
> +    ScheduleData *SD = WorkList.back();
> +    WorkList.pop_back();
> +
> +    ScheduleData *BundleMember = SD;
> +    while (BundleMember) {
> +      assert(isInSchedulingRegion(BundleMember));
> +      if (!BundleMember->hasValidDependencies()) {
> +
> +        DEBUG(dbgs() << "SLP:       update deps of " << *BundleMember << "\n");
> +        BundleMember->Dependencies = 0;
> +        BundleMember->resetUnscheduledDeps();
> +
> +        // Handle def-use chain dependencies.
> +        for (User *U : BundleMember->Inst->users()) {
> +          if (isa<Instruction>(U)) {
> +            ScheduleData *UseSD = getScheduleData(U);
> +            if (UseSD && isInSchedulingRegion(UseSD->FirstInBundle)) {
> +              BundleMember->Dependencies++;
> +              ScheduleData *DestBundle = UseSD->FirstInBundle;
> +              if (!DestBundle->IsScheduled) {
> +                BundleMember->incrementUnscheduledDeps(1);
> +              }
> +              if (!DestBundle->hasValidDependencies()) {
> +                WorkList.push_back(DestBundle);
> +              }
> +            }
> +          } else {
> +            // I'm not sure if this can ever happen. But we need to be safe.
> +            // This lets the instruction/bundle never be scheduled and eventally
> +            // disable vectorization.
> +            BundleMember->Dependencies++;
> +            BundleMember->incrementUnscheduledDeps(1);
> +          }
> +        }
> +
> +        // Handle the memory dependencies.
> +        ScheduleData *DepDest = BundleMember->NextLoadStore;
> +        if (DepDest) {
> +          AliasAnalysis::Location SrcLoc = getLocation(BundleMember->Inst, AA);
> +          bool SrcMayWrite = BundleMember->Inst->mayWriteToMemory();
> +
> +          while (DepDest) {
> +            assert(isInSchedulingRegion(DepDest));
> +            if (SrcMayWrite || DepDest->Inst->mayWriteToMemory()) {
> +              AliasAnalysis::Location DstLoc = getLocation(DepDest->Inst, AA);
> +              if (!SrcLoc.Ptr || !DstLoc.Ptr || AA->alias(SrcLoc, DstLoc)) {
> +                DepDest->MemoryDependencies.push_back(BundleMember);
> +                BundleMember->Dependencies++;
> +                ScheduleData *DestBundle = DepDest->FirstInBundle;
> +                if (!DestBundle->IsScheduled) {
> +                  BundleMember->incrementUnscheduledDeps(1);
> +                }
> +                if (!DestBundle->hasValidDependencies()) {
> +                  WorkList.push_back(DestBundle);
> +                }
> +              }
> +            }
> +            DepDest = DepDest->NextLoadStore;
> +          }
> +        }
> +      }
> +      BundleMember = BundleMember->NextInBundle;
> +    }
> +    if (InsertInReadyList && SD->isReady()) {
> +      ReadyInsts.push_back(SD);
> +      DEBUG(dbgs() << "SLP:     gets ready on update: " << *SD->Inst << "\n");
> +    }
> +  }
> +}
> +
> +void BoUpSLP::BlockScheduling::resetSchedule() {
> +  assert(ScheduleStart &&
> +         "tried to reset schedule on block which has not been scheduled");
> +  for (Instruction *I = ScheduleStart; I != ScheduleEnd; I = I->getNextNode()) {
> +    ScheduleData *SD = getScheduleData(I);
> +    assert(isInSchedulingRegion(SD));
> +    SD->IsScheduled = false;
> +    SD->resetUnscheduledDeps();
> +  }
> +  ReadyInsts.clear();
> +}
> +
> +void BoUpSLP::scheduleBlock(BasicBlock *BB) {
> +  DEBUG(dbgs() << "SLP: schedule block " << BB->getName() << "\n");
> +
> +  BlockScheduling *BS = BlocksSchedules[BB].get();
> +  if (!BS || !BS->ScheduleStart)
> +    return;
> +
> +  BS->resetSchedule();
> +
> +  // For the real scheduling we use a more sophisticated ready-list: it is
> +  // sorted by the original instruction location. This lets the final schedule
> +  // be as  close as possible to the original instruction order.
> +  struct ScheduleDataCompare {
> +    bool operator()(ScheduleData *SD1, ScheduleData *SD2) {
> +      return SD2->SchedulingPriority < SD1->SchedulingPriority;
> +    }
> +  };
> +  std::set<ScheduleData *, ScheduleDataCompare> ReadyInsts;
> +
> +  // Ensure that all depencency data is updated and fill the ready-list with
> +  // initial instructions.
> +  int Idx = 0;
> +  int NumToSchedule = 0;
> +  for (auto *I = BS->ScheduleStart; I != BS->ScheduleEnd;
> +       I = I->getNextNode()) {
> +    ScheduleData *SD = BS->getScheduleData(I);
> +    assert(
> +        SD->isPartOfBundle() == (ScalarToTreeEntry.count(SD->Inst) != 0) &&
> +        "scheduler and vectorizer have different opinion on what is a bundle");
> +    SD->FirstInBundle->SchedulingPriority = Idx++;
> +    if (SD->isSchedulingEntity()) {
> +      BS->calculateDependencies(SD, false, AA);
> +      NumToSchedule++;
> +    }
> +  }
> +  BS->initialFillReadyList(ReadyInsts);
> +
> +  Instruction *LastScheduledInst = BS->ScheduleEnd;
> +
> +  // Do the "real" scheduling.
> +  while (!ReadyInsts.empty()) {
> +    ScheduleData *picked = *ReadyInsts.begin();
> +    ReadyInsts.erase(ReadyInsts.begin());
> +
> +    // Move the scheduled instruction(s) to their dedicated places, if not
> +    // there yet.
> +    ScheduleData *BundleMember = picked;
> +    while (BundleMember) {
> +      Instruction *pickedInst = BundleMember->Inst;
> +      if (LastScheduledInst->getNextNode() != pickedInst) {
> +        BB->getInstList().remove(pickedInst);
> +        BB->getInstList().insert(LastScheduledInst, pickedInst);
> +      }
> +      LastScheduledInst = pickedInst;
> +      BundleMember = BundleMember->NextInBundle;
> +    }
> +
> +    BS->schedule(picked, ReadyInsts);
> +    NumToSchedule--;
> +  }
> +  assert(NumToSchedule == 0 && "could not schedule all instructions");
> +
> +  // Avoid duplicate scheduling of the block.
> +  BS->ScheduleStart = nullptr;
> +}
> +
>  /// The SLPVectorizer Pass.
>  struct SLPVectorizer : public FunctionPass {
>    typedef SmallVector<StoreInst *, 8> StoreList;
>
> Modified: llvm/trunk/test/Transforms/SLPVectorizer/X86/crash_vectorizeTree.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SLPVectorizer/X86/crash_vectorizeTree.ll?rev=214494&r1=214493&r2=214494&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/SLPVectorizer/X86/crash_vectorizeTree.ll (original)
> +++ llvm/trunk/test/Transforms/SLPVectorizer/X86/crash_vectorizeTree.ll Fri Aug  1 04:20:42 2014
> @@ -1,4 +1,4 @@
> -; RUN: opt -slp-vectorizer -mtriple=x86_64-apple-macosx10.9.0 -mcpu=corei7-avx -S < %s | FileCheck %s
> +; RUN: opt -basicaa -slp-vectorizer -mtriple=x86_64-apple-macosx10.9.0 -mcpu=corei7-avx -S < %s | FileCheck %s
>  target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
>  target triple = "x86_64-apple-macosx10.9.0"
>
>
> Modified: llvm/trunk/test/Transforms/SLPVectorizer/X86/in-tree-user.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SLPVectorizer/X86/in-tree-user.ll?rev=214494&r1=214493&r2=214494&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/SLPVectorizer/X86/in-tree-user.ll (original)
> +++ llvm/trunk/test/Transforms/SLPVectorizer/X86/in-tree-user.ll Fri Aug  1 04:20:42 2014
> @@ -5,9 +5,11 @@ target triple = "x86_64-apple-macosx10.7
>
>  @.str = private unnamed_addr constant [6 x i8] c"bingo\00", align 1
>
> -; We can't vectorize when the roots are used inside the tree.
> +; Uses inside the tree must be scheduled after the corresponding tree bundle.
>  ;CHECK-LABEL: @in_tree_user(
> -;CHECK-NOT: load <2 x double>
> +;CHECK: load <2 x double>
> +;CHECK: fadd <2 x double>
> +;CHECK: InTreeUser = fadd
>  ;CHECK: ret
>  define void @in_tree_user(double* nocapture %A, i32 %n) {
>  entry:
> @@ -22,7 +24,7 @@ for.body:
>    %mul1 = fmul double %conv, %1
>    %mul2 = fmul double %mul1, 7.000000e+00
>    %add = fadd double %mul2, 5.000000e+00
> -  %BadValue = fadd double %add, %add    ; <------------------ In tree user.
> +  %InTreeUser = fadd double %add, %add    ; <------------------ In tree user.
>    %2 = or i64 %0, 1
>    %arrayidx6 = getelementptr inbounds double* %A, i64 %2
>    %3 = load double* %arrayidx6, align 8
> @@ -43,6 +45,7 @@ for.inc:
>    br i1 %exitcond, label %for.end, label %for.body
>
>  for.end:                                          ; preds = %for.inc
> +  store double %InTreeUser, double* %A, align 8   ; Avoid dead code elimination of the InTreeUser.
>    ret void
>  }
>
>
> Added: llvm/trunk/test/Transforms/SLPVectorizer/X86/scheduling.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SLPVectorizer/X86/scheduling.ll?rev=214494&view=auto
> ==============================================================================
> --- llvm/trunk/test/Transforms/SLPVectorizer/X86/scheduling.ll (added)
> +++ llvm/trunk/test/Transforms/SLPVectorizer/X86/scheduling.ll Fri Aug  1 04:20:42 2014
> @@ -0,0 +1,78 @@
> +; RUN: opt < %s -basicaa -slp-vectorizer -S -mtriple=i386-apple-macosx10.8.0 -mcpu=corei7-avx | FileCheck %s
> +
> +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
> +target triple = "x86_64-apple-macosx10.9.0"
> +
> +;CHECK-LABEL: @foo
> +;CHECK: load <4 x i32>
> +;CHECK: load <4 x i32>
> +;CHECK: %[[S1:.+]] = add <4 x i32>
> +;CHECK-DAG: store <4 x i32> %[[S1]]
> +;CHECK-DAG: %[[A1:.+]] = add nsw i32
> +;CHECK-DAG: %[[A2:.+]] = add nsw i32 %[[A1]]
> +;CHECK-DAG: %[[A3:.+]] = add nsw i32 %[[A2]]
> +;CHECK-DAG: %[[A4:.+]] = add nsw i32 %[[A3]]
> +;CHECK: ret i32 %[[A4]]
> +
> +define i32 @foo(i32* nocapture readonly %diff) #0 {
> +entry:
> +  %m2 = alloca [8 x [8 x i32]], align 16
> +  %0 = bitcast [8 x [8 x i32]]* %m2 to i8*
> +  br label %for.body
> +
> +for.body:                                         ; preds = %for.body, %entry
> +  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
> +  %a.088 = phi i32 [ 0, %entry ], [ %add52, %for.body ]
> +  %1 = shl i64 %indvars.iv, 3
> +  %arrayidx = getelementptr inbounds i32* %diff, i64 %1
> +  %2 = load i32* %arrayidx, align 4
> +  %3 = or i64 %1, 4
> +  %arrayidx2 = getelementptr inbounds i32* %diff, i64 %3
> +  %4 = load i32* %arrayidx2, align 4
> +  %add3 = add nsw i32 %4, %2
> +  %arrayidx6 = getelementptr inbounds [8 x [8 x i32]]* %m2, i64 0, i64 %indvars.iv, i64 0
> +  store i32 %add3, i32* %arrayidx6, align 16
> +  %add10 = add nsw i32 %add3, %a.088
> +  %5 = or i64 %1, 1
> +  %arrayidx13 = getelementptr inbounds i32* %diff, i64 %5
> +  %6 = load i32* %arrayidx13, align 4
> +  %7 = or i64 %1, 5
> +  %arrayidx16 = getelementptr inbounds i32* %diff, i64 %7
> +  %8 = load i32* %arrayidx16, align 4
> +  %add17 = add nsw i32 %8, %6
> +  %arrayidx20 = getelementptr inbounds [8 x [8 x i32]]* %m2, i64 0, i64 %indvars.iv, i64 1
> +  store i32 %add17, i32* %arrayidx20, align 4
> +  %add24 = add nsw i32 %add10, %add17
> +  %9 = or i64 %1, 2
> +  %arrayidx27 = getelementptr inbounds i32* %diff, i64 %9
> +  %10 = load i32* %arrayidx27, align 4
> +  %11 = or i64 %1, 6
> +  %arrayidx30 = getelementptr inbounds i32* %diff, i64 %11
> +  %12 = load i32* %arrayidx30, align 4
> +  %add31 = add nsw i32 %12, %10
> +  %arrayidx34 = getelementptr inbounds [8 x [8 x i32]]* %m2, i64 0, i64 %indvars.iv, i64 2
> +  store i32 %add31, i32* %arrayidx34, align 8
> +  %add38 = add nsw i32 %add24, %add31
> +  %13 = or i64 %1, 3
> +  %arrayidx41 = getelementptr inbounds i32* %diff, i64 %13
> +  %14 = load i32* %arrayidx41, align 4
> +  %15 = or i64 %1, 7
> +  %arrayidx44 = getelementptr inbounds i32* %diff, i64 %15
> +  %16 = load i32* %arrayidx44, align 4
> +  %add45 = add nsw i32 %16, %14
> +  %arrayidx48 = getelementptr inbounds [8 x [8 x i32]]* %m2, i64 0, i64 %indvars.iv, i64 3
> +  store i32 %add45, i32* %arrayidx48, align 4
> +  %add52 = add nsw i32 %add38, %add45
> +  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
> +  %exitcond = icmp eq i64 %indvars.iv.next, 8
> +  br i1 %exitcond, label %for.end, label %for.body
> +
> +for.end:                                          ; preds = %for.body
> +  %arraydecay = getelementptr inbounds [8 x [8 x i32]]* %m2, i64 0, i64 0
> +  call void @ff([8 x i32]* %arraydecay) #1
> +  ret i32 %add52
> +}
> +
> +declare void @ff([8 x i32]*) #2
> +
> +
>
>
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