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Revert "[LV] Autovectorization for the all-in-one histogram intrinsic" #98493

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Merged
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Jul 11, 2024
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Revert "[LV] Autovectorization for the all-in-one histogram intrinsic" #98493

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52 changes: 8 additions & 44 deletions llvm/include/llvm/Analysis/LoopAccessAnalysis.h
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Original file line number Diff line number Diff line change
Expand Up @@ -144,9 +144,7 @@ class MemoryDepChecker {
// on MinDepDistBytes.
BackwardVectorizable,
// Same, but may prevent store-to-load forwarding.
BackwardVectorizableButPreventsForwarding,
// Access is to a loop loaded value, but is part of a histogram operation.
Histogram
BackwardVectorizableButPreventsForwarding
};

/// String version of the types.
Expand Down Expand Up @@ -203,8 +201,7 @@ class MemoryDepChecker {
/// Only checks sets with elements in \p CheckDeps.
bool areDepsSafe(DepCandidates &AccessSets, MemAccessInfoList &CheckDeps,
const DenseMap<Value *, SmallVector<const Value *, 16>>
&UnderlyingObjects,
const SmallPtrSetImpl<const Value *> &HistogramPtrs);
&UnderlyingObjects);

/// No memory dependence was encountered that would inhibit
/// vectorization.
Expand Down Expand Up @@ -355,8 +352,7 @@ class MemoryDepChecker {
isDependent(const MemAccessInfo &A, unsigned AIdx, const MemAccessInfo &B,
unsigned BIdx,
const DenseMap<Value *, SmallVector<const Value *, 16>>
&UnderlyingObjects,
const SmallPtrSetImpl<const Value *> &HistogramPtrs);
&UnderlyingObjects);

/// Check whether the data dependence could prevent store-load
/// forwarding.
Expand Down Expand Up @@ -397,8 +393,7 @@ class MemoryDepChecker {
const MemAccessInfo &A, Instruction *AInst, const MemAccessInfo &B,
Instruction *BInst,
const DenseMap<Value *, SmallVector<const Value *, 16>>
&UnderlyingObjects,
const SmallPtrSetImpl<const Value *> &HistogramPtrs);
&UnderlyingObjects);
};

class RuntimePointerChecking;
Expand Down Expand Up @@ -450,15 +445,6 @@ struct PointerDiffInfo {
NeedsFreeze(NeedsFreeze) {}
};

struct HistogramInfo {
LoadInst *Load;
Instruction *Update;
StoreInst *Store;

HistogramInfo(LoadInst *Load, Instruction *Update, StoreInst *Store)
: Load(Load), Update(Update), Store(Store) {}
};

/// Holds information about the memory runtime legality checks to verify
/// that a group of pointers do not overlap.
class RuntimePointerChecking {
Expand Down Expand Up @@ -639,13 +625,6 @@ class RuntimePointerChecking {
/// Checks for both memory dependences and the SCEV predicates contained in the
/// PSE must be emitted in order for the results of this analysis to be valid.
class LoopAccessInfo {
/// Represents whether the memory access dependencies in the loop:
/// * Prohibit vectorization
/// * Allow for vectorization (possibly with runtime checks)
/// * Allow for vectorization (possibly with runtime checks),
/// as long as histogram operations are supported.
enum VecMemPossible { CantVec = 0, NormalVec = 1, HistogramVec = 2 };

public:
LoopAccessInfo(Loop *L, ScalarEvolution *SE, const TargetTransformInfo *TTI,
const TargetLibraryInfo *TLI, AAResults *AA, DominatorTree *DT,
Expand All @@ -657,11 +636,7 @@ class LoopAccessInfo {
/// hasStoreStoreDependenceInvolvingLoopInvariantAddress and
/// hasLoadStoreDependenceInvolvingLoopInvariantAddress also need to be
/// checked.
bool canVectorizeMemory() const { return CanVecMem == NormalVec; }

bool canVectorizeMemoryWithHistogram() const {
return CanVecMem == NormalVec || CanVecMem == HistogramVec;
}
bool canVectorizeMemory() const { return CanVecMem; }

/// Return true if there is a convergent operation in the loop. There may
/// still be reported runtime pointer checks that would be required, but it is
Expand Down Expand Up @@ -689,10 +664,6 @@ class LoopAccessInfo {
unsigned getNumStores() const { return NumStores; }
unsigned getNumLoads() const { return NumLoads;}

const SmallVectorImpl<HistogramInfo> &getHistograms() const {
return Histograms;
}

/// The diagnostics report generated for the analysis. E.g. why we
/// couldn't analyze the loop.
const OptimizationRemarkAnalysis *getReport() const { return Report.get(); }
Expand Down Expand Up @@ -744,8 +715,8 @@ class LoopAccessInfo {
private:
/// Analyze the loop. Returns true if all memory access in the loop can be
/// vectorized.
VecMemPossible analyzeLoop(AAResults *AA, LoopInfo *LI,
const TargetLibraryInfo *TLI, DominatorTree *DT);
bool analyzeLoop(AAResults *AA, LoopInfo *LI, const TargetLibraryInfo *TLI,
DominatorTree *DT);

/// Check if the structure of the loop allows it to be analyzed by this
/// pass.
Expand Down Expand Up @@ -786,7 +757,7 @@ class LoopAccessInfo {
unsigned NumStores = 0;

/// Cache the result of analyzeLoop.
VecMemPossible CanVecMem = CantVec;
bool CanVecMem = false;
bool HasConvergentOp = false;

/// Indicator that there are two non vectorizable stores to the same uniform
Expand All @@ -806,13 +777,6 @@ class LoopAccessInfo {
/// If an access has a symbolic strides, this maps the pointer value to
/// the stride symbol.
DenseMap<Value *, const SCEV *> SymbolicStrides;

/// Holds the load, update, and store instructions for all histogram-style
/// operations found in the loop.
SmallVector<HistogramInfo, 2> Histograms;

/// Storing Histogram Pointers
SmallPtrSet<const Value *, 2> HistogramPtrs;
};

/// Return the SCEV corresponding to a pointer with the symbolic stride
Expand Down
17 changes: 0 additions & 17 deletions llvm/include/llvm/Transforms/Vectorize/LoopVectorizationLegality.h
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Original file line number Diff line number Diff line change
Expand Up @@ -390,23 +390,6 @@ class LoopVectorizationLegality {
unsigned getNumStores() const { return LAI->getNumStores(); }
unsigned getNumLoads() const { return LAI->getNumLoads(); }

std::optional<const HistogramInfo *> getHistogramInfo(Instruction *I) const {
for (const HistogramInfo &HGram : LAI->getHistograms())
if (HGram.Load == I || HGram.Update == I || HGram.Store == I)
return &HGram;

return std::nullopt;
}

std::optional<const HistogramInfo *>
getHistogramForStore(StoreInst *SI) const {
for (const HistogramInfo &HGram : LAI->getHistograms())
if (HGram.Store == SI)
return &HGram;

return std::nullopt;
}

PredicatedScalarEvolution *getPredicatedScalarEvolution() const {
return &PSE;
}
Expand Down
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