Commit 9f7dedc3 authored by Adam Nemet's avatar Adam Nemet
Browse files

[LAA] Introduce RuntimePointerChecking::PointerInfo, NFC

Turn this structure-of-arrays (i.e. the various pointer attributes) into
array-of-structures.

llvm-svn: 242219
parent 7cdebac0
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+32 −23
Original line number Diff line number Diff line
@@ -295,18 +295,37 @@ private:
/// This struct holds information about the memory runtime legality check that
/// a group of pointers do not overlap.
struct RuntimePointerChecking {
  struct PointerInfo {
    /// Holds the pointer value that we need to check.
    TrackingVH<Value> PointerValue;
    /// Holds the pointer value at the beginning of the loop.
    const SCEV *Start;
    /// Holds the pointer value at the end of the loop.
    const SCEV *End;
    /// Holds the information if this pointer is used for writing to memory.
    bool IsWritePtr;
    /// Holds the id of the set of pointers that could be dependent because of a
    /// shared underlying object.
    unsigned DependencySetId;
    /// Holds the id of the disjoint alias set to which this pointer belongs.
    unsigned AliasSetId;
    /// SCEV for the access.
    const SCEV *Expr;

    PointerInfo(Value *PointerValue, const SCEV *Start, const SCEV *End,
                bool IsWritePtr, unsigned DependencySetId, unsigned AliasSetId,
                const SCEV *Expr)
        : PointerValue(PointerValue), Start(Start), End(End),
          IsWritePtr(IsWritePtr), DependencySetId(DependencySetId),
          AliasSetId(AliasSetId), Expr(Expr) {}
  };

  RuntimePointerChecking(ScalarEvolution *SE) : Need(false), SE(SE) {}

  /// Reset the state of the pointer runtime information.
  void reset() {
    Need = false;
    Pointers.clear();
    Starts.clear();
    Ends.clear();
    IsWritePtr.clear();
    DependencySetId.clear();
    AliasSetId.clear();
    Exprs.clear();
  }

  /// Insert a pointer and calculate the start and end SCEVs.
@@ -322,8 +341,8 @@ struct RuntimePointerChecking {
    /// \brief Create a new pointer checking group containing a single
    /// pointer, with index \p Index in RtCheck.
    CheckingPtrGroup(unsigned Index, RuntimePointerChecking &RtCheck)
        : RtCheck(RtCheck), High(RtCheck.Ends[Index]),
          Low(RtCheck.Starts[Index]) {
        : RtCheck(RtCheck), High(RtCheck.Pointers[Index].End),
          Low(RtCheck.Pointers[Index].Start) {
      Members.push_back(Index);
    }

@@ -387,23 +406,13 @@ struct RuntimePointerChecking {

  /// This flag indicates if we need to add the runtime check.
  bool Need;
  /// Holds the pointers that we need to check.
  SmallVector<TrackingVH<Value>, 2> Pointers;
  /// Holds the pointer value at the beginning of the loop.
  SmallVector<const SCEV *, 2> Starts;
  /// Holds the pointer value at the end of the loop.
  SmallVector<const SCEV *, 2> Ends;
  /// Holds the information if this pointer is used for writing to memory.
  SmallVector<bool, 2> IsWritePtr;
  /// Holds the id of the set of pointers that could be dependent because of a
  /// shared underlying object.
  SmallVector<unsigned, 2> DependencySetId;
  /// Holds the id of the disjoint alias set to which this pointer belongs.
  SmallVector<unsigned, 2> AliasSetId;
  /// Holds at position i the SCEV for the access i
  SmallVector<const SCEV *, 2> Exprs;

  /// Information about the pointers that may require checking.
  SmallVector<PointerInfo, 2> Pointers;

  /// Holds a partitioning of pointers into "check groups".
  SmallVector<CheckingPtrGroup, 2> CheckingGroups;

  /// Holds a pointer to the ScalarEvolution analysis.
  ScalarEvolution *SE;
};
+33 −29
Original line number Diff line number Diff line
@@ -128,13 +128,8 @@ void RuntimePointerChecking::insert(Loop *Lp, Value *Ptr, bool WritePtr,
  assert(AR && "Invalid addrec expression");
  const SCEV *Ex = SE->getBackedgeTakenCount(Lp);
  const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE);
  Pointers.push_back(Ptr);
  Starts.push_back(AR->getStart());
  Ends.push_back(ScEnd);
  IsWritePtr.push_back(WritePtr);
  DependencySetId.push_back(DepSetId);
  AliasSetId.push_back(ASId);
  Exprs.push_back(Sc);
  Pointers.emplace_back(Ptr, AR->getStart(), ScEnd, WritePtr, DepSetId, ASId,
                        Sc);
}

bool RuntimePointerChecking::needsChecking(
@@ -162,24 +157,27 @@ static const SCEV *getMinFromExprs(const SCEV *I, const SCEV *J,
}

bool RuntimePointerChecking::CheckingPtrGroup::addPointer(unsigned Index) {
  const SCEV *Start = RtCheck.Pointers[Index].Start;
  const SCEV *End = RtCheck.Pointers[Index].End;

  // Compare the starts and ends with the known minimum and maximum
  // of this set. We need to know how we compare against the min/max
  // of the set in order to be able to emit memchecks.
  const SCEV *Min0 = getMinFromExprs(RtCheck.Starts[Index], Low, RtCheck.SE);
  const SCEV *Min0 = getMinFromExprs(Start, Low, RtCheck.SE);
  if (!Min0)
    return false;

  const SCEV *Min1 = getMinFromExprs(RtCheck.Ends[Index], High, RtCheck.SE);
  const SCEV *Min1 = getMinFromExprs(End, High, RtCheck.SE);
  if (!Min1)
    return false;

  // Update the low bound  expression if we've found a new min value.
  if (Min0 == RtCheck.Starts[Index])
    Low = RtCheck.Starts[Index];
  if (Min0 == Start)
    Low = Start;

  // Update the high bound expression if we've found a new max value.
  if (Min1 != RtCheck.Ends[Index])
    High = RtCheck.Ends[Index];
  if (Min1 != End)
    High = End;

  Members.push_back(Index);
  return true;
@@ -217,8 +215,8 @@ void RuntimePointerChecking::groupChecks(
  unsigned TotalComparisons = 0;

  DenseMap<Value *, unsigned> PositionMap;
  for (unsigned Pointer = 0; Pointer < Pointers.size(); ++Pointer)
    PositionMap[Pointers[Pointer]] = Pointer;
  for (unsigned Index = 0; Index < Pointers.size(); ++Index)
    PositionMap[Pointers[Index].PointerValue] = Index;

  // We need to keep track of what pointers we've already seen so we
  // don't process them twice.
@@ -233,7 +231,8 @@ void RuntimePointerChecking::groupChecks(
    if (Seen.count(I))
      continue;

    MemoryDepChecker::MemAccessInfo Access(Pointers[I], IsWritePtr[I]);
    MemoryDepChecker::MemAccessInfo Access(Pointers[I].PointerValue,
                                           Pointers[I].IsWritePtr);

    SmallVector<CheckingPtrGroup, 2> Groups;
    auto LeaderI = DepCands.findValue(DepCands.getLeaderValue(Access));
@@ -283,16 +282,19 @@ void RuntimePointerChecking::groupChecks(

bool RuntimePointerChecking::needsChecking(
    unsigned I, unsigned J, const SmallVectorImpl<int> *PtrPartition) const {
  const PointerInfo &PointerI = Pointers[I];
  const PointerInfo &PointerJ = Pointers[J];

  // No need to check if two readonly pointers intersect.
  if (!IsWritePtr[I] && !IsWritePtr[J])
  if (!PointerI.IsWritePtr && !PointerJ.IsWritePtr)
    return false;

  // Only need to check pointers between two different dependency sets.
  if (DependencySetId[I] == DependencySetId[J])
  if (PointerI.DependencySetId == PointerJ.DependencySetId)
    return false;

  // Only need to check pointers in the same alias set.
  if (AliasSetId[I] != AliasSetId[J])
  if (PointerI.AliasSetId != PointerJ.AliasSetId)
    return false;

  // If PtrPartition is set omit checks between pointers of the same partition.
@@ -319,8 +321,8 @@ void RuntimePointerChecking::print(
        OS.indent(Depth + 2) << "Comparing group " << I << ":\n";

        for (unsigned K = 0; K < CheckingGroups[I].Members.size(); ++K) {
          OS.indent(Depth + 2) << *Pointers[CheckingGroups[I].Members[K]]
                               << "\n";
          OS.indent(Depth + 2)
              << *Pointers[CheckingGroups[I].Members[K]].PointerValue << "\n";
          if (PtrPartition)
            OS << " (Partition: "
               << (*PtrPartition)[CheckingGroups[I].Members[K]] << ")"
@@ -330,8 +332,8 @@ void RuntimePointerChecking::print(
        OS.indent(Depth + 2) << "Against group " << J << ":\n";

        for (unsigned K = 0; K < CheckingGroups[J].Members.size(); ++K) {
          OS.indent(Depth + 2) << *Pointers[CheckingGroups[J].Members[K]]
                               << "\n";
          OS.indent(Depth + 2)
              << *Pointers[CheckingGroups[J].Members[K]].PointerValue << "\n";
          if (PtrPartition)
            OS << " (Partition: "
               << (*PtrPartition)[CheckingGroups[J].Members[K]] << ")"
@@ -345,7 +347,8 @@ void RuntimePointerChecking::print(
    OS.indent(Depth + 4) << "(Low: " << *CheckingGroups[I].Low
                         << " High: " << *CheckingGroups[I].High << ")\n";
    for (unsigned J = 0; J < CheckingGroups[I].Members.size(); ++J) {
      OS.indent(Depth + 6) << "Member: " << *Exprs[CheckingGroups[I].Members[J]]
      OS.indent(Depth + 6) << "Member: "
                           << *Pointers[CheckingGroups[I].Members[J]].Expr
                           << "\n";
    }
  }
@@ -575,14 +578,15 @@ bool AccessAnalysis::canCheckPtrAtRT(RuntimePointerChecking &RtCheck,
  for (unsigned i = 0; i < NumPointers; ++i) {
    for (unsigned j = i + 1; j < NumPointers; ++j) {
      // Only need to check pointers between two different dependency sets.
      if (RtCheck.DependencySetId[i] == RtCheck.DependencySetId[j])
      if (RtCheck.Pointers[i].DependencySetId ==
          RtCheck.Pointers[j].DependencySetId)
       continue;
      // Only need to check pointers in the same alias set.
      if (RtCheck.AliasSetId[i] != RtCheck.AliasSetId[j])
      if (RtCheck.Pointers[i].AliasSetId != RtCheck.Pointers[j].AliasSetId)
        continue;

      Value *PtrI = RtCheck.Pointers[i];
      Value *PtrJ = RtCheck.Pointers[j];
      Value *PtrI = RtCheck.Pointers[i].PointerValue;
      Value *PtrJ = RtCheck.Pointers[j].PointerValue;

      unsigned ASi = PtrI->getType()->getPointerAddressSpace();
      unsigned ASj = PtrJ->getType()->getPointerAddressSpace();
@@ -1577,7 +1581,7 @@ std::pair<Instruction *, Instruction *> LoopAccessInfo::addRuntimeCheck(
  for (unsigned i = 0; i < PtrRtChecking.CheckingGroups.size(); ++i) {
    const RuntimePointerChecking::CheckingPtrGroup &CG =
        PtrRtChecking.CheckingGroups[i];
    Value *Ptr = PtrRtChecking.Pointers[CG.Members[0]];
    Value *Ptr = PtrRtChecking.Pointers[CG.Members[0]].PointerValue;
    const SCEV *Sc = SE->getSCEV(Ptr);

    if (SE->isLoopInvariant(Sc, TheLoop)) {
+2 −2
Original line number Diff line number Diff line
@@ -437,9 +437,9 @@ public:
    unsigned N = RtPtrCheck->Pointers.size();
    SmallVector<int, 8> PtrToPartitions(N);
    for (unsigned I = 0; I < N; ++I) {
      Value *Ptr = RtPtrCheck->Pointers[I];
      Value *Ptr = RtPtrCheck->Pointers[I].PointerValue;
      auto Instructions =
          LAI.getInstructionsForAccess(Ptr, RtPtrCheck->IsWritePtr[I]);
          LAI.getInstructionsForAccess(Ptr, RtPtrCheck->Pointers[I].IsWritePtr);

      int &Partition = PtrToPartitions[I];
      // First set it to uninitialized.