[llvm] r214494 - SLPVectorizer: improved scheduling algorithm.

Erik Eckstein eeckstein at apple.com
Fri Aug 1 12:10:44 PDT 2014


Hi Eric, David,

thanks a lot for your detailed feedback and your help!

Erik


On 01 Aug 2014, at 20:29, Eric Christopher <echristo at gmail.com> wrote:

> 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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