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Revert "[Analysis]Add getPointersDiff function to improve compile time."

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This reverts commit 065a14a12d2694f26f4e894641f5ab8cfc5da8bd to
investigate and fix crash in SLP vectorizer.
This commit is contained in:
Alexey Bataev 2021-03-23 13:17:26 -07:00
parent 9601d11568
commit 2cb8308176
4 changed files with 140 additions and 161 deletions
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9
include/llvm/Analysis/LoopAccessAnalysis.h
View File

@ -679,15 +679,6 @@ int64_t getPtrStride(PredicatedScalarEvolution &PSE, Value *Ptr, const Loop *Lp,
const ValueToValueMap &StridesMap = ValueToValueMap(),
bool Assume = false, bool ShouldCheckWrap = true);
/// Returns the distance between the pointers \p PtrA and \p PtrB iff they are
/// compatible and it is possible to calculate the distance between them. This
/// is a simple API that does not depend on the analysis pass.
/// \param StrictCheck Ensure that the calculated distance matches the
/// type-based one after all the bitcasts removal in the provided pointers.
Optional<int> getPointersDiff(Value *PtrA, Value *PtrB, const DataLayout &DL,
ScalarEvolution &SE, bool StrictCheck = false,
bool CheckType = true);
/// Attempt to sort the pointers in \p VL and return the sorted indices
/// in \p SortedIndices, if reordering is required.
///

198
lib/Analysis/LoopAccessAnalysis.cpp
View File

@ -1124,123 +1124,139 @@ int64_t llvm::getPtrStride(PredicatedScalarEvolution &PSE, Value *Ptr,
return Stride;
}
Optional<int> llvm::getPointersDiff(Value *PtrA, Value *PtrB,
const DataLayout &DL, ScalarEvolution &SE,
bool StrictCheck, bool CheckType) {
assert(PtrA && PtrB && "Expected non-nullptr pointers.");
// Make sure that A and B are different pointers.
if (PtrA == PtrB)
return 0;
// Make sure that PtrA and PtrB have the same type if required
if (CheckType && PtrA->getType() != PtrB->getType())
return None;
unsigned ASA = PtrA->getType()->getPointerAddressSpace();
unsigned ASB = PtrB->getType()->getPointerAddressSpace();
// Check that the address spaces match.
if (ASA != ASB)
return None;
unsigned IdxWidth = DL.getIndexSizeInBits(ASA);
APInt OffsetA(IdxWidth, 0), OffsetB(IdxWidth, 0);
Value *PtrA1 = PtrA->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetA);
Value *PtrB1 = PtrB->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetB);
int Val;
if (PtrA1 == PtrB1) {
// Retrieve the address space again as pointer stripping now tracks through
// `addrspacecast`.
ASA = cast<PointerType>(PtrA1->getType())->getAddressSpace();
ASB = cast<PointerType>(PtrB1->getType())->getAddressSpace();
// Check that the address spaces match and that the pointers are valid.
if (ASA != ASB)
return None;
IdxWidth = DL.getIndexSizeInBits(ASA);
OffsetA = OffsetA.sextOrTrunc(IdxWidth);
OffsetB = OffsetB.sextOrTrunc(IdxWidth);
OffsetB -= OffsetA;
Val = OffsetB.getSExtValue();
} else {
// Otherwise compute the distance with SCEV between the base pointers.
const SCEV *PtrSCEVA = SE.getSCEV(PtrA);
const SCEV *PtrSCEVB = SE.getSCEV(PtrB);
const auto *Diff =
dyn_cast<SCEVConstant>(SE.getMinusSCEV(PtrSCEVB, PtrSCEVA));
if (!Diff)
return None;
Val = Diff->getAPInt().getSExtValue();
}
Type *Ty = cast<PointerType>(PtrA->getType())->getElementType();
int Size = DL.getTypeStoreSize(Ty);
int Dist = Val / Size;
// Ensure that the calculated distance matches the type-based one after all
// the bitcasts removal in the provided pointers.
if (!StrictCheck || Dist * Size == Val)
return Dist;
return None;
}
bool llvm::sortPtrAccesses(ArrayRef<Value *> VL, const DataLayout &DL,
ScalarEvolution &SE,
SmallVectorImpl<unsigned> &SortedIndices) {
assert(llvm::all_of(
VL, [](const Value *V) { return V->getType()->isPointerTy(); }) &&
"Expected list of pointer operands.");
SmallVector<std::pair<int64_t, Value *>, 4> OffValPairs;
OffValPairs.reserve(VL.size());
// Walk over the pointers, and map each of them to an offset relative to
// first pointer in the array.
Value *Ptr0 = VL[0];
const SCEV *Scev0 = SE.getSCEV(Ptr0);
Value *Obj0 = getUnderlyingObject(Ptr0);
using DistOrdPair = std::pair<int64_t, int>;
auto Compare = [](const DistOrdPair &L, const DistOrdPair &R) {
return L.first < R.first;
};
std::set<DistOrdPair, decltype(Compare)> Offsets(Compare);
Offsets.emplace(0, 0);
int Cnt = 1;
bool IsConsecutive = true;
for (auto *Ptr : VL.drop_front()) {
Optional<int> Diff = getPointersDiff(Ptr0, Ptr, DL, SE);
llvm::SmallSet<int64_t, 4> Offsets;
for (auto *Ptr : VL) {
// TODO: Outline this code as a special, more time consuming, version of
// computeConstantDifference() function.
if (Ptr->getType()->getPointerAddressSpace() !=
Ptr0->getType()->getPointerAddressSpace())
return false;
// If a pointer refers to a different underlying object, bail - the
// pointers are by definition incomparable.
Value *CurrObj = getUnderlyingObject(Ptr);
if (CurrObj != Obj0)
return false;
const SCEV *Scev = SE.getSCEV(Ptr);
const auto *Diff = dyn_cast<SCEVConstant>(SE.getMinusSCEV(Scev, Scev0));
// The pointers may not have a constant offset from each other, or SCEV
// may just not be smart enough to figure out they do. Regardless,
// there's nothing we can do.
if (!Diff)
return false;
// Check if the pointer with the same offset is found.
int64_t Offset = *Diff;
auto Res = Offsets.emplace(Offset, Cnt);
if (!Res.second)
int64_t Offset = Diff->getAPInt().getSExtValue();
if (!Offsets.insert(Offset).second)
return false;
// Consecutive order if the inserted element is the last one.
IsConsecutive = IsConsecutive && std::next(Res.first) == Offsets.end();
++Cnt;
OffValPairs.emplace_back(Offset, Ptr);
}
SortedIndices.clear();
if (!IsConsecutive) {
// Fill SortedIndices array only if it is non-consecutive.
SortedIndices.resize(VL.size());
Cnt = 0;
for (const std::pair<int64_t, int> &Pair : Offsets) {
IsConsecutive = IsConsecutive && Cnt == Pair.second;
SortedIndices[Cnt] = Pair.second;
++Cnt;
}
}
SortedIndices.resize(VL.size());
std::iota(SortedIndices.begin(), SortedIndices.end(), 0);
// Sort the memory accesses and keep the order of their uses in UseOrder.
llvm::stable_sort(SortedIndices, [&](unsigned Left, unsigned Right) {
return OffValPairs[Left].first < OffValPairs[Right].first;
});
// Check if the order is consecutive already.
if (llvm::all_of(SortedIndices, [&SortedIndices](const unsigned I) {
return I == SortedIndices[I];
}))
SortedIndices.clear();
return true;
}
/// Take the address space operand from the Load/Store instruction.
/// Returns -1 if this is not a valid Load/Store instruction.
static unsigned getAddressSpaceOperand(Value *I) {
if (LoadInst *L = dyn_cast<LoadInst>(I))
return L->getPointerAddressSpace();
if (StoreInst *S = dyn_cast<StoreInst>(I))
return S->getPointerAddressSpace();
return -1;
}
/// Returns true if the memory operations \p A and \p B are consecutive.
bool llvm::isConsecutiveAccess(Value *A, Value *B, const DataLayout &DL,
ScalarEvolution &SE, bool CheckType) {
Value *PtrA = getLoadStorePointerOperand(A);
Value *PtrB = getLoadStorePointerOperand(B);
if (!PtrA || !PtrB)
unsigned ASA = getAddressSpaceOperand(A);
unsigned ASB = getAddressSpaceOperand(B);
// Check that the address spaces match and that the pointers are valid.
if (!PtrA || !PtrB || (ASA != ASB))
return false;
Optional<int> Diff =
getPointersDiff(PtrA, PtrB, DL, SE, /*StrictCheck=*/true, CheckType);
return Diff && *Diff == 1;
// Make sure that A and B are different pointers.
if (PtrA == PtrB)
return false;
// Make sure that A and B have the same type if required.
if (CheckType && PtrA->getType() != PtrB->getType())
return false;
unsigned IdxWidth = DL.getIndexSizeInBits(ASA);
Type *Ty = cast<PointerType>(PtrA->getType())->getElementType();
APInt OffsetA(IdxWidth, 0), OffsetB(IdxWidth, 0);
PtrA = PtrA->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetA);
PtrB = PtrB->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetB);
// Retrieve the address space again as pointer stripping now tracks through
// `addrspacecast`.
ASA = cast<PointerType>(PtrA->getType())->getAddressSpace();
ASB = cast<PointerType>(PtrB->getType())->getAddressSpace();
// Check that the address spaces match and that the pointers are valid.
if (ASA != ASB)
return false;
IdxWidth = DL.getIndexSizeInBits(ASA);
OffsetA = OffsetA.sextOrTrunc(IdxWidth);
OffsetB = OffsetB.sextOrTrunc(IdxWidth);
APInt Size(IdxWidth, DL.getTypeStoreSize(Ty));
// OffsetDelta = OffsetB - OffsetA;
const SCEV *OffsetSCEVA = SE.getConstant(OffsetA);
const SCEV *OffsetSCEVB = SE.getConstant(OffsetB);
const SCEV *OffsetDeltaSCEV = SE.getMinusSCEV(OffsetSCEVB, OffsetSCEVA);
const APInt &OffsetDelta = cast<SCEVConstant>(OffsetDeltaSCEV)->getAPInt();
// Check if they are based on the same pointer. That makes the offsets
// sufficient.
if (PtrA == PtrB)
return OffsetDelta == Size;
// Compute the necessary base pointer delta to have the necessary final delta
// equal to the size.
// BaseDelta = Size - OffsetDelta;
const SCEV *SizeSCEV = SE.getConstant(Size);
const SCEV *BaseDelta = SE.getMinusSCEV(SizeSCEV, OffsetDeltaSCEV);
// Otherwise compute the distance with SCEV between the base pointers.
const SCEV *PtrSCEVA = SE.getSCEV(PtrA);
const SCEV *PtrSCEVB = SE.getSCEV(PtrB);
const SCEV *X = SE.getAddExpr(PtrSCEVA, BaseDelta);
return X == PtrSCEVB;
}
MemoryDepChecker::VectorizationSafetyStatus

77
lib/Transforms/Vectorize/SLPVectorizer.cpp
View File

@ -941,16 +941,10 @@ public:
ScalarEvolution &SE) {
auto *LI1 = dyn_cast<LoadInst>(V1);
auto *LI2 = dyn_cast<LoadInst>(V2);
if (LI1 && LI2) {
if (LI1->getParent() != LI2->getParent())
return VLOperands::ScoreFail;
Optional<int> Dist =
getPointersDiff(LI1->getPointerOperand(), LI2->getPointerOperand(),
DL, SE, /*StrictCheck=*/true);
return (Dist && *Dist == 1) ? VLOperands::ScoreConsecutiveLoads
: VLOperands::ScoreFail;
}
if (LI1 && LI2)
return isConsecutiveAccess(LI1, LI2, DL, SE)
? VLOperands::ScoreConsecutiveLoads
: VLOperands::ScoreFail;
auto *C1 = dyn_cast<Constant>(V1);
auto *C2 = dyn_cast<Constant>(V2);
@ -2877,9 +2871,13 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
Ptr0 = PointerOps[CurrentOrder.front()];
PtrN = PointerOps[CurrentOrder.back()];
}
Optional<int> Diff = getPointersDiff(Ptr0, PtrN, *DL, *SE);
const SCEV *Scev0 = SE->getSCEV(Ptr0);
const SCEV *ScevN = SE->getSCEV(PtrN);
const auto *Diff =
dyn_cast<SCEVConstant>(SE->getMinusSCEV(ScevN, Scev0));
uint64_t Size = DL->getTypeAllocSize(ScalarTy);
// Check that the sorted loads are consecutive.
if (static_cast<unsigned>(*Diff) == VL.size() - 1) {
if (Diff && Diff->getAPInt() == (VL.size() - 1) * Size) {
if (CurrentOrder.empty()) {
// Original loads are consecutive and does not require reordering.
++NumOpsWantToKeepOriginalOrder;
@ -3152,9 +3150,13 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
Ptr0 = PointerOps[CurrentOrder.front()];
PtrN = PointerOps[CurrentOrder.back()];
}
Optional<int> Dist = getPointersDiff(Ptr0, PtrN, *DL, *SE);
const SCEV *Scev0 = SE->getSCEV(Ptr0);
const SCEV *ScevN = SE->getSCEV(PtrN);
const auto *Diff =
dyn_cast<SCEVConstant>(SE->getMinusSCEV(ScevN, Scev0));
uint64_t Size = DL->getTypeAllocSize(ScalarTy);
// Check that the sorted pointer operands are consecutive.
if (static_cast<unsigned>(*Dist) == VL.size() - 1) {
if (Diff && Diff->getAPInt() == (VL.size() - 1) * Size) {
if (CurrentOrder.empty()) {
// Original stores are consecutive and does not require reordering.
++NumOpsWantToKeepOriginalOrder;
@ -6105,41 +6107,20 @@ bool SLPVectorizerPass::vectorizeStores(ArrayRef<StoreInst *> Stores,
int E = Stores.size();
SmallBitVector Tails(E, false);
SmallVector<int, 16> ConsecutiveChain(E, E + 1);
int MaxIter = MaxStoreLookup.getValue();
SmallVector<std::pair<int, int>, 16> ConsecutiveChain(
E, std::make_pair(E, INT_MAX));
SmallVector<SmallBitVector, 4> CheckedPairs(E, SmallBitVector(E, false));
int IterCnt;
auto &&FindConsecutiveAccess = [this, &Stores, &Tails, &IterCnt, MaxIter,
&CheckedPairs,
&ConsecutiveChain](int K, int Idx) {
if (IterCnt >= MaxIter)
return true;
if (CheckedPairs[Idx].test(K))
return ConsecutiveChain[K].second == 1 &&
ConsecutiveChain[K].first == Idx;
++IterCnt;
CheckedPairs[Idx].set(K);
CheckedPairs[K].set(Idx);
Optional<int> Diff = getPointersDiff(Stores[K]->getPointerOperand(),
Stores[Idx]->getPointerOperand(), *DL,
*SE, /*StrictCheck=*/true);
if (!Diff || *Diff == 0)
return false;
int Val = *Diff;
if (Val < 0) {
if (ConsecutiveChain[Idx].second > -Val) {
Tails.set(K);
ConsecutiveChain[Idx] = std::make_pair(K, -Val);
}
return false;
}
if (ConsecutiveChain[K].second <= Val)
if (!isConsecutiveAccess(Stores[K], Stores[Idx], *DL, *SE))
return false;
Tails.set(Idx);
ConsecutiveChain[K] = std::make_pair(Idx, Val);
return Val == 1;
ConsecutiveChain[K] = Idx;
return true;
};
// Do a quadratic search on all of the given stores in reverse order and find
// all of the pairs of stores that follow each other.
@ -6159,28 +6140,16 @@ bool SLPVectorizerPass::vectorizeStores(ArrayRef<StoreInst *> Stores,
// For stores that start but don't end a link in the chain:
for (int Cnt = E; Cnt > 0; --Cnt) {
int I = Cnt - 1;
if (ConsecutiveChain[I].first == E || Tails.test(I))
if (ConsecutiveChain[I] == E + 1 || Tails.test(I))
continue;
// We found a store instr that starts a chain. Now follow the chain and try
// to vectorize it.
BoUpSLP::ValueList Operands;
// Collect the chain into a list.
while (I != E && !VectorizedStores.count(Stores[I])) {
while (I != E + 1 && !VectorizedStores.count(Stores[I])) {
Operands.push_back(Stores[I]);
Tails.set(I);
if (ConsecutiveChain[I].second != 1) {
// Mark the new end in the chain and go back, if required. It might be
// required if the original stores comes in reversed order, for example.
if (ConsecutiveChain[I].first != E &&
Tails.test(ConsecutiveChain[I].first)) {
Tails.reset(ConsecutiveChain[I].first);
if (Cnt < ConsecutiveChain[I].first + 2)
Cnt = ConsecutiveChain[I].first + 2;
}
break;
}
// Move to the next value in the chain.
I = ConsecutiveChain[I].first;
I = ConsecutiveChain[I];
}
unsigned MaxVecRegSize = R.getMaxVecRegSize();

17
test/Transforms/SLPVectorizer/X86/pr35497.ll
View File

@ -1,7 +1,7 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -slp-vectorizer -mattr=+sse2 -S | FileCheck %s --check-prefix=SSE
; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -slp-vectorizer -mattr=+avx -S | FileCheck %s --check-prefix=AVX
; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -slp-vectorizer -mattr=+avx2 -S | FileCheck %s --check-prefix=AVX
; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -slp-vectorizer -slp-vectorizer -mattr=+sse2 -S | FileCheck %s --check-prefix=SSE
; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -slp-vectorizer -slp-vectorizer -mattr=+avx -S | FileCheck %s --check-prefix=AVX
; RUN: opt < %s -mtriple=x86_64-unknown-linux-gnu -slp-vectorizer -slp-vectorizer -mattr=+avx2 -S | FileCheck %s --check-prefix=AVX
%class.1 = type { %class.2 }
%class.2 = type { %"class.3" }
@ -117,10 +117,13 @@ define void @pr35497() local_unnamed_addr #0 {
; AVX-NEXT: [[ARRAYIDX2_6:%.*]] = getelementptr inbounds [0 x i64], [0 x i64]* undef, i64 0, i64 0
; AVX-NEXT: [[TMP10:%.*]] = bitcast i64* [[ARRAYIDX2_6]] to <2 x i64>*
; AVX-NEXT: store <2 x i64> [[TMP4]], <2 x i64>* [[TMP10]], align 1
; AVX-NEXT: [[TMP11:%.*]] = lshr <2 x i64> [[TMP4]], <i64 6, i64 6>
; AVX-NEXT: [[TMP12:%.*]] = add nuw nsw <2 x i64> [[TMP9]], [[TMP11]]
; AVX-NEXT: [[TMP13:%.*]] = bitcast i64* [[ARRAYIDX2_2]] to <2 x i64>*
; AVX-NEXT: store <2 x i64> [[TMP12]], <2 x i64>* [[TMP13]], align 1
; AVX-NEXT: [[TMP11:%.*]] = extractelement <2 x i64> [[TMP4]], i32 0
; AVX-NEXT: [[TMP12:%.*]] = insertelement <2 x i64> poison, i64 [[TMP11]], i32 0
; AVX-NEXT: [[TMP13:%.*]] = insertelement <2 x i64> [[TMP12]], i64 [[TMP5]], i32 1
; AVX-NEXT: [[TMP14:%.*]] = lshr <2 x i64> [[TMP13]], <i64 6, i64 6>
; AVX-NEXT: [[TMP15:%.*]] = add nuw nsw <2 x i64> [[TMP9]], [[TMP14]]
; AVX-NEXT: [[TMP16:%.*]] = bitcast i64* [[ARRAYIDX2_2]] to <2 x i64>*
; AVX-NEXT: store <2 x i64> [[TMP15]], <2 x i64>* [[TMP16]], align 1
; AVX-NEXT: ret void
;
entry: