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-rw-r--r--lib/Analysis/LoopAccessAnalysis.cpp417
1 files changed, 211 insertions, 206 deletions
diff --git a/lib/Analysis/LoopAccessAnalysis.cpp b/lib/Analysis/LoopAccessAnalysis.cpp
index 7bedd40..1818e93 100644
--- a/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/lib/Analysis/LoopAccessAnalysis.cpp
@@ -15,11 +15,13 @@
#include "llvm/Analysis/LoopAccessAnalysis.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/VectorUtils.h"
using namespace llvm;
@@ -49,6 +51,13 @@ unsigned VectorizerParams::RuntimeMemoryCheckThreshold;
/// Maximum SIMD width.
const unsigned VectorizerParams::MaxVectorWidth = 64;
+/// \brief We collect interesting dependences up to this threshold.
+static cl::opt<unsigned> MaxInterestingDependence(
+ "max-interesting-dependences", cl::Hidden,
+ cl::desc("Maximum number of interesting dependences collected by "
+ "loop-access analysis (default = 100)"),
+ cl::init(100));
+
bool VectorizerParams::isInterleaveForced() {
return ::VectorizationInterleave.getNumOccurrences() > 0;
}
@@ -120,8 +129,8 @@ void LoopAccessInfo::RuntimePointerCheck::insert(
AliasSetId.push_back(ASId);
}
-bool LoopAccessInfo::RuntimePointerCheck::needsChecking(unsigned I,
- unsigned J) const {
+bool LoopAccessInfo::RuntimePointerCheck::needsChecking(
+ unsigned I, unsigned J, const SmallVectorImpl<int> *PtrPartition) const {
// No need to check if two readonly pointers intersect.
if (!IsWritePtr[I] && !IsWritePtr[J])
return false;
@@ -134,11 +143,19 @@ bool LoopAccessInfo::RuntimePointerCheck::needsChecking(unsigned I,
if (AliasSetId[I] != AliasSetId[J])
return false;
+ // If PtrPartition is set omit checks between pointers of the same partition.
+ // Partition number -1 means that the pointer is used in multiple partitions.
+ // In this case we can't omit the check.
+ if (PtrPartition && (*PtrPartition)[I] != -1 &&
+ (*PtrPartition)[I] == (*PtrPartition)[J])
+ return false;
+
return true;
}
-void LoopAccessInfo::RuntimePointerCheck::print(raw_ostream &OS,
- unsigned Depth) const {
+void LoopAccessInfo::RuntimePointerCheck::print(
+ raw_ostream &OS, unsigned Depth,
+ const SmallVectorImpl<int> *PtrPartition) const {
unsigned NumPointers = Pointers.size();
if (NumPointers == 0)
return;
@@ -147,10 +164,16 @@ void LoopAccessInfo::RuntimePointerCheck::print(raw_ostream &OS,
unsigned N = 0;
for (unsigned I = 0; I < NumPointers; ++I)
for (unsigned J = I + 1; J < NumPointers; ++J)
- if (needsChecking(I, J)) {
+ if (needsChecking(I, J, PtrPartition)) {
OS.indent(Depth) << N++ << ":\n";
- OS.indent(Depth + 2) << *Pointers[I] << "\n";
- OS.indent(Depth + 2) << *Pointers[J] << "\n";
+ OS.indent(Depth + 2) << *Pointers[I];
+ if (PtrPartition)
+ OS << " (Partition: " << (*PtrPartition)[I] << ")";
+ OS << "\n";
+ OS.indent(Depth + 2) << *Pointers[J];
+ if (PtrPartition)
+ OS << " (Partition: " << (*PtrPartition)[J] << ")";
+ OS << "\n";
}
}
@@ -165,11 +188,9 @@ public:
typedef PointerIntPair<Value *, 1, bool> MemAccessInfo;
typedef SmallPtrSet<MemAccessInfo, 8> MemAccessInfoSet;
- /// \brief Set of potential dependent memory accesses.
- typedef EquivalenceClasses<MemAccessInfo> DepCandidates;
-
- AccessAnalysis(const DataLayout *Dl, AliasAnalysis *AA, DepCandidates &DA) :
- DL(Dl), AST(*AA), DepCands(DA), IsRTCheckNeeded(false) {}
+ AccessAnalysis(const DataLayout &Dl, AliasAnalysis *AA,
+ MemoryDepChecker::DepCandidates &DA)
+ : DL(Dl), AST(*AA), DepCands(DA), IsRTCheckNeeded(false) {}
/// \brief Register a load and whether it is only read from.
void addLoad(AliasAnalysis::Location &Loc, bool IsReadOnly) {
@@ -217,14 +238,14 @@ private:
/// Set of all accesses.
PtrAccessSet Accesses;
+ const DataLayout &DL;
+
/// Set of accesses that need a further dependence check.
MemAccessInfoSet CheckDeps;
/// Set of pointers that are read only.
SmallPtrSet<Value*, 16> ReadOnlyPtr;
- const DataLayout *DL;
-
/// An alias set tracker to partition the access set by underlying object and
//intrinsic property (such as TBAA metadata).
AliasSetTracker AST;
@@ -232,7 +253,7 @@ private:
/// Sets of potentially dependent accesses - members of one set share an
/// underlying pointer. The set "CheckDeps" identfies which sets really need a
/// dependence check.
- DepCandidates &DepCands;
+ MemoryDepChecker::DepCandidates &DepCands;
bool IsRTCheckNeeded;
};
@@ -252,8 +273,8 @@ static bool hasComputableBounds(ScalarEvolution *SE,
/// \brief Check the stride of the pointer and ensure that it does not wrap in
/// the address space.
-static int isStridedPtr(ScalarEvolution *SE, const DataLayout *DL, Value *Ptr,
- const Loop *Lp, const ValueToValueMap &StridesMap);
+static int isStridedPtr(ScalarEvolution *SE, Value *Ptr, const Loop *Lp,
+ const ValueToValueMap &StridesMap);
bool AccessAnalysis::canCheckPtrAtRT(
LoopAccessInfo::RuntimePointerCheck &RtCheck, unsigned &NumComparisons,
@@ -289,10 +310,10 @@ bool AccessAnalysis::canCheckPtrAtRT(
++NumReadPtrChecks;
if (hasComputableBounds(SE, StridesMap, Ptr) &&
- // When we run after a failing dependency check we have to make sure we
- // don't have wrapping pointers.
+ // When we run after a failing dependency check we have to make sure
+ // we don't have wrapping pointers.
(!ShouldCheckStride ||
- isStridedPtr(SE, DL, Ptr, TheLoop, StridesMap) == 1)) {
+ isStridedPtr(SE, Ptr, TheLoop, StridesMap) == 1)) {
// The id of the dependence set.
unsigned DepId;
@@ -362,7 +383,7 @@ void AccessAnalysis::processMemAccesses() {
DEBUG(dbgs() << "LAA: Processing memory accesses...\n");
DEBUG(dbgs() << " AST: "; AST.dump());
- DEBUG(dbgs() << "LAA: Accesses:\n");
+ DEBUG(dbgs() << "LAA: Accesses(" << Accesses.size() << "):\n");
DEBUG({
for (auto A : Accesses)
dbgs() << "\t" << *A.getPointer() << " (" <<
@@ -460,124 +481,6 @@ void AccessAnalysis::processMemAccesses() {
}
}
-namespace {
-/// \brief Checks memory dependences among accesses to the same underlying
-/// object to determine whether there vectorization is legal or not (and at
-/// which vectorization factor).
-///
-/// This class works under the assumption that we already checked that memory
-/// locations with different underlying pointers are "must-not alias".
-/// We use the ScalarEvolution framework to symbolically evalutate access
-/// functions pairs. Since we currently don't restructure the loop we can rely
-/// on the program order of memory accesses to determine their safety.
-/// At the moment we will only deem accesses as safe for:
-/// * A negative constant distance assuming program order.
-///
-/// Safe: tmp = a[i + 1]; OR a[i + 1] = x;
-/// a[i] = tmp; y = a[i];
-///
-/// The latter case is safe because later checks guarantuee that there can't
-/// be a cycle through a phi node (that is, we check that "x" and "y" is not
-/// the same variable: a header phi can only be an induction or a reduction, a
-/// reduction can't have a memory sink, an induction can't have a memory
-/// source). This is important and must not be violated (or we have to
-/// resort to checking for cycles through memory).
-///
-/// * A positive constant distance assuming program order that is bigger
-/// than the biggest memory access.
-///
-/// tmp = a[i] OR b[i] = x
-/// a[i+2] = tmp y = b[i+2];
-///
-/// Safe distance: 2 x sizeof(a[0]), and 2 x sizeof(b[0]), respectively.
-///
-/// * Zero distances and all accesses have the same size.
-///
-class MemoryDepChecker {
-public:
- typedef PointerIntPair<Value *, 1, bool> MemAccessInfo;
- typedef SmallPtrSet<MemAccessInfo, 8> MemAccessInfoSet;
-
- MemoryDepChecker(ScalarEvolution *Se, const DataLayout *Dl, const Loop *L)
- : SE(Se), DL(Dl), InnermostLoop(L), AccessIdx(0),
- ShouldRetryWithRuntimeCheck(false) {}
-
- /// \brief Register the location (instructions are given increasing numbers)
- /// of a write access.
- void addAccess(StoreInst *SI) {
- Value *Ptr = SI->getPointerOperand();
- Accesses[MemAccessInfo(Ptr, true)].push_back(AccessIdx);
- InstMap.push_back(SI);
- ++AccessIdx;
- }
-
- /// \brief Register the location (instructions are given increasing numbers)
- /// of a write access.
- void addAccess(LoadInst *LI) {
- Value *Ptr = LI->getPointerOperand();
- Accesses[MemAccessInfo(Ptr, false)].push_back(AccessIdx);
- InstMap.push_back(LI);
- ++AccessIdx;
- }
-
- /// \brief Check whether the dependencies between the accesses are safe.
- ///
- /// Only checks sets with elements in \p CheckDeps.
- bool areDepsSafe(AccessAnalysis::DepCandidates &AccessSets,
- MemAccessInfoSet &CheckDeps, const ValueToValueMap &Strides);
-
- /// \brief The maximum number of bytes of a vector register we can vectorize
- /// the accesses safely with.
- unsigned getMaxSafeDepDistBytes() { return MaxSafeDepDistBytes; }
-
- /// \brief In same cases when the dependency check fails we can still
- /// vectorize the loop with a dynamic array access check.
- bool shouldRetryWithRuntimeCheck() { return ShouldRetryWithRuntimeCheck; }
-
-private:
- ScalarEvolution *SE;
- const DataLayout *DL;
- const Loop *InnermostLoop;
-
- /// \brief Maps access locations (ptr, read/write) to program order.
- DenseMap<MemAccessInfo, std::vector<unsigned> > Accesses;
-
- /// \brief Memory access instructions in program order.
- SmallVector<Instruction *, 16> InstMap;
-
- /// \brief The program order index to be used for the next instruction.
- unsigned AccessIdx;
-
- // We can access this many bytes in parallel safely.
- unsigned MaxSafeDepDistBytes;
-
- /// \brief If we see a non-constant dependence distance we can still try to
- /// vectorize this loop with runtime checks.
- bool ShouldRetryWithRuntimeCheck;
-
- /// \brief Check whether there is a plausible dependence between the two
- /// accesses.
- ///
- /// Access \p A must happen before \p B in program order. The two indices
- /// identify the index into the program order map.
- ///
- /// This function checks whether there is a plausible dependence (or the
- /// absence of such can't be proved) between the two accesses. If there is a
- /// plausible dependence but the dependence distance is bigger than one
- /// element access it records this distance in \p MaxSafeDepDistBytes (if this
- /// distance is smaller than any other distance encountered so far).
- /// Otherwise, this function returns true signaling a possible dependence.
- bool isDependent(const MemAccessInfo &A, unsigned AIdx,
- const MemAccessInfo &B, unsigned BIdx,
- const ValueToValueMap &Strides);
-
- /// \brief Check whether the data dependence could prevent store-load
- /// forwarding.
- bool couldPreventStoreLoadForward(unsigned Distance, unsigned TypeByteSize);
-};
-
-} // end anonymous namespace
-
static bool isInBoundsGep(Value *Ptr) {
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr))
return GEP->isInBounds();
@@ -585,8 +488,8 @@ static bool isInBoundsGep(Value *Ptr) {
}
/// \brief Check whether the access through \p Ptr has a constant stride.
-static int isStridedPtr(ScalarEvolution *SE, const DataLayout *DL, Value *Ptr,
- const Loop *Lp, const ValueToValueMap &StridesMap) {
+static int isStridedPtr(ScalarEvolution *SE, Value *Ptr, const Loop *Lp,
+ const ValueToValueMap &StridesMap) {
const Type *Ty = Ptr->getType();
assert(Ty->isPointerTy() && "Unexpected non-ptr");
@@ -640,7 +543,8 @@ static int isStridedPtr(ScalarEvolution *SE, const DataLayout *DL, Value *Ptr,
return 0;
}
- int64_t Size = DL->getTypeAllocSize(PtrTy->getElementType());
+ auto &DL = Lp->getHeader()->getModule()->getDataLayout();
+ int64_t Size = DL.getTypeAllocSize(PtrTy->getElementType());
const APInt &APStepVal = C->getValue()->getValue();
// Huge step value - give up.
@@ -665,6 +569,54 @@ static int isStridedPtr(ScalarEvolution *SE, const DataLayout *DL, Value *Ptr,
return Stride;
}
+bool MemoryDepChecker::Dependence::isSafeForVectorization(DepType Type) {
+ switch (Type) {
+ case NoDep:
+ case Forward:
+ case BackwardVectorizable:
+ return true;
+
+ case Unknown:
+ case ForwardButPreventsForwarding:
+ case Backward:
+ case BackwardVectorizableButPreventsForwarding:
+ return false;
+ }
+ llvm_unreachable("unexpected DepType!");
+}
+
+bool MemoryDepChecker::Dependence::isInterestingDependence(DepType Type) {
+ switch (Type) {
+ case NoDep:
+ case Forward:
+ return false;
+
+ case BackwardVectorizable:
+ case Unknown:
+ case ForwardButPreventsForwarding:
+ case Backward:
+ case BackwardVectorizableButPreventsForwarding:
+ return true;
+ }
+ llvm_unreachable("unexpected DepType!");
+}
+
+bool MemoryDepChecker::Dependence::isPossiblyBackward() const {
+ switch (Type) {
+ case NoDep:
+ case Forward:
+ case ForwardButPreventsForwarding:
+ return false;
+
+ case Unknown:
+ case BackwardVectorizable:
+ case Backward:
+ case BackwardVectorizableButPreventsForwarding:
+ return true;
+ }
+ llvm_unreachable("unexpected DepType!");
+}
+
bool MemoryDepChecker::couldPreventStoreLoadForward(unsigned Distance,
unsigned TypeByteSize) {
// If loads occur at a distance that is not a multiple of a feasible vector
@@ -704,9 +656,10 @@ bool MemoryDepChecker::couldPreventStoreLoadForward(unsigned Distance,
return false;
}
-bool MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
- const MemAccessInfo &B, unsigned BIdx,
- const ValueToValueMap &Strides) {
+MemoryDepChecker::Dependence::DepType
+MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
+ const MemAccessInfo &B, unsigned BIdx,
+ const ValueToValueMap &Strides) {
assert (AIdx < BIdx && "Must pass arguments in program order");
Value *APtr = A.getPointer();
@@ -716,18 +669,18 @@ bool MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
// Two reads are independent.
if (!AIsWrite && !BIsWrite)
- return false;
+ return Dependence::NoDep;
// We cannot check pointers in different address spaces.
if (APtr->getType()->getPointerAddressSpace() !=
BPtr->getType()->getPointerAddressSpace())
- return true;
+ return Dependence::Unknown;
const SCEV *AScev = replaceSymbolicStrideSCEV(SE, Strides, APtr);
const SCEV *BScev = replaceSymbolicStrideSCEV(SE, Strides, BPtr);
- int StrideAPtr = isStridedPtr(SE, DL, APtr, InnermostLoop, Strides);
- int StrideBPtr = isStridedPtr(SE, DL, BPtr, InnermostLoop, Strides);
+ int StrideAPtr = isStridedPtr(SE, APtr, InnermostLoop, Strides);
+ int StrideBPtr = isStridedPtr(SE, BPtr, InnermostLoop, Strides);
const SCEV *Src = AScev;
const SCEV *Sink = BScev;
@@ -756,19 +709,20 @@ bool MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
// the address space.
if (!StrideAPtr || !StrideBPtr || StrideAPtr != StrideBPtr){
DEBUG(dbgs() << "Non-consecutive pointer access\n");
- return true;
+ return Dependence::Unknown;
}
const SCEVConstant *C = dyn_cast<SCEVConstant>(Dist);
if (!C) {
DEBUG(dbgs() << "LAA: Dependence because of non-constant distance\n");
ShouldRetryWithRuntimeCheck = true;
- return true;
+ return Dependence::Unknown;
}
Type *ATy = APtr->getType()->getPointerElementType();
Type *BTy = BPtr->getType()->getPointerElementType();
- unsigned TypeByteSize = DL->getTypeAllocSize(ATy);
+ auto &DL = InnermostLoop->getHeader()->getModule()->getDataLayout();
+ unsigned TypeByteSize = DL.getTypeAllocSize(ATy);
// Negative distances are not plausible dependencies.
const APInt &Val = C->getValue()->getValue();
@@ -777,19 +731,19 @@ bool MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
if (IsTrueDataDependence &&
(couldPreventStoreLoadForward(Val.abs().getZExtValue(), TypeByteSize) ||
ATy != BTy))
- return true;
+ return Dependence::ForwardButPreventsForwarding;
DEBUG(dbgs() << "LAA: Dependence is negative: NoDep\n");
- return false;
+ return Dependence::Forward;
}
// Write to the same location with the same size.
// Could be improved to assert type sizes are the same (i32 == float, etc).
if (Val == 0) {
if (ATy == BTy)
- return false;
+ return Dependence::NoDep;
DEBUG(dbgs() << "LAA: Zero dependence difference but different types\n");
- return true;
+ return Dependence::Unknown;
}
assert(Val.isStrictlyPositive() && "Expect a positive value");
@@ -797,7 +751,7 @@ bool MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
if (ATy != BTy) {
DEBUG(dbgs() <<
"LAA: ReadWrite-Write positive dependency with different types\n");
- return true;
+ return Dependence::Unknown;
}
unsigned Distance = (unsigned) Val.getZExtValue();
@@ -816,7 +770,7 @@ bool MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
Distance < TypeByteSize * ForcedUnroll * ForcedFactor) {
DEBUG(dbgs() << "LAA: Failure because of Positive distance "
<< Val.getSExtValue() << '\n');
- return true;
+ return Dependence::Backward;
}
// Positive distance bigger than max vectorization factor.
@@ -826,15 +780,15 @@ bool MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
bool IsTrueDataDependence = (!AIsWrite && BIsWrite);
if (IsTrueDataDependence &&
couldPreventStoreLoadForward(Distance, TypeByteSize))
- return true;
+ return Dependence::BackwardVectorizableButPreventsForwarding;
DEBUG(dbgs() << "LAA: Positive distance " << Val.getSExtValue() <<
" with max VF = " << MaxSafeDepDistBytes / TypeByteSize << '\n');
- return false;
+ return Dependence::BackwardVectorizable;
}
-bool MemoryDepChecker::areDepsSafe(AccessAnalysis::DepCandidates &AccessSets,
+bool MemoryDepChecker::areDepsSafe(DepCandidates &AccessSets,
MemAccessInfoSet &CheckDeps,
const ValueToValueMap &Strides) {
@@ -860,9 +814,33 @@ bool MemoryDepChecker::areDepsSafe(AccessAnalysis::DepCandidates &AccessSets,
I1E = Accesses[*AI].end(); I1 != I1E; ++I1)
for (std::vector<unsigned>::iterator I2 = Accesses[*OI].begin(),
I2E = Accesses[*OI].end(); I2 != I2E; ++I2) {
- if (*I1 < *I2 && isDependent(*AI, *I1, *OI, *I2, Strides))
- return false;
- if (*I2 < *I1 && isDependent(*OI, *I2, *AI, *I1, Strides))
+ auto A = std::make_pair(&*AI, *I1);
+ auto B = std::make_pair(&*OI, *I2);
+
+ assert(*I1 != *I2);
+ if (*I1 > *I2)
+ std::swap(A, B);
+
+ Dependence::DepType Type =
+ isDependent(*A.first, A.second, *B.first, B.second, Strides);
+ SafeForVectorization &= Dependence::isSafeForVectorization(Type);
+
+ // Gather dependences unless we accumulated MaxInterestingDependence
+ // dependences. In that case return as soon as we find the first
+ // unsafe dependence. This puts a limit on this quadratic
+ // algorithm.
+ if (RecordInterestingDependences) {
+ if (Dependence::isInterestingDependence(Type))
+ InterestingDependences.push_back(
+ Dependence(A.second, B.second, Type));
+
+ if (InterestingDependences.size() >= MaxInterestingDependence) {
+ RecordInterestingDependences = false;
+ InterestingDependences.clear();
+ DEBUG(dbgs() << "Too many dependences, stopped recording\n");
+ }
+ }
+ if (!RecordInterestingDependences && !SafeForVectorization)
return false;
}
++OI;
@@ -870,7 +848,34 @@ bool MemoryDepChecker::areDepsSafe(AccessAnalysis::DepCandidates &AccessSets,
AI++;
}
}
- return true;
+
+ DEBUG(dbgs() << "Total Interesting Dependences: "
+ << InterestingDependences.size() << "\n");
+ return SafeForVectorization;
+}
+
+SmallVector<Instruction *, 4>
+MemoryDepChecker::getInstructionsForAccess(Value *Ptr, bool isWrite) const {
+ MemAccessInfo Access(Ptr, isWrite);
+ auto &IndexVector = Accesses.find(Access)->second;
+
+ SmallVector<Instruction *, 4> Insts;
+ std::transform(IndexVector.begin(), IndexVector.end(),
+ std::back_inserter(Insts),
+ [&](unsigned Idx) { return this->InstMap[Idx]; });
+ return Insts;
+}
+
+const char *MemoryDepChecker::Dependence::DepName[] = {
+ "NoDep", "Unknown", "Forward", "ForwardButPreventsForwarding", "Backward",
+ "BackwardVectorizable", "BackwardVectorizableButPreventsForwarding"};
+
+void MemoryDepChecker::Dependence::print(
+ raw_ostream &OS, unsigned Depth,
+ const SmallVectorImpl<Instruction *> &Instrs) const {
+ OS.indent(Depth) << DepName[Type] << ":\n";
+ OS.indent(Depth + 2) << *Instrs[Source] << " -> \n";
+ OS.indent(Depth + 2) << *Instrs[Destination] << "\n";
}
bool LoopAccessInfo::canAnalyzeLoop() {
@@ -939,7 +944,6 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
PtrRtCheck.Need = false;
const bool IsAnnotatedParallel = TheLoop->isAnnotatedParallel();
- MemoryDepChecker DepChecker(SE, DL, TheLoop);
// For each block.
for (Loop::block_iterator bb = TheLoop->block_begin(),
@@ -960,6 +964,12 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
if (Call && getIntrinsicIDForCall(Call, TLI))
continue;
+ // If the function has an explicit vectorized counterpart, we can safely
+ // assume that it can be vectorized.
+ if (Call && !Call->isNoBuiltin() && Call->getCalledFunction() &&
+ TLI->isFunctionVectorizable(Call->getCalledFunction()->getName()))
+ continue;
+
LoadInst *Ld = dyn_cast<LoadInst>(it);
if (!Ld || (!Ld->isSimple() && !IsAnnotatedParallel)) {
emitAnalysis(LoopAccessReport(Ld)
@@ -1008,8 +1018,9 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
return;
}
- AccessAnalysis::DepCandidates DependentAccesses;
- AccessAnalysis Accesses(DL, AA, DependentAccesses);
+ MemoryDepChecker::DepCandidates DependentAccesses;
+ AccessAnalysis Accesses(TheLoop->getHeader()->getModule()->getDataLayout(),
+ AA, DependentAccesses);
// Holds the analyzed pointers. We don't want to call GetUnderlyingObjects
// multiple times on the same object. If the ptr is accessed twice, once
@@ -1068,8 +1079,7 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
// read a few words, modify, and write a few words, and some of the
// words may be written to the same address.
bool IsReadOnlyPtr = false;
- if (Seen.insert(Ptr).second ||
- !isStridedPtr(SE, DL, Ptr, TheLoop, Strides)) {
+ if (Seen.insert(Ptr).second || !isStridedPtr(SE, Ptr, TheLoop, Strides)) {
++NumReads;
IsReadOnlyPtr = true;
}
@@ -1099,7 +1109,6 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
// Find pointers with computable bounds. We are going to use this information
// to place a runtime bound check.
- unsigned NumComparisons = 0;
bool CanDoRT = false;
if (NeedRTCheck)
CanDoRT = Accesses.canCheckPtrAtRT(PtrRtCheck, NumComparisons, SE, TheLoop,
@@ -1113,18 +1122,10 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
if (NumComparisons == 0 && NeedRTCheck)
NeedRTCheck = false;
- // Check that we did not collect too many pointers or found an unsizeable
- // pointer.
- if (!CanDoRT || NumComparisons > RuntimeMemoryCheckThreshold) {
- PtrRtCheck.reset();
- CanDoRT = false;
- }
-
- if (CanDoRT) {
+ // Check that we found the bounds for the pointer.
+ if (CanDoRT)
DEBUG(dbgs() << "LAA: We can perform a memory runtime check if needed.\n");
- }
-
- if (NeedRTCheck && !CanDoRT) {
+ else if (NeedRTCheck) {
emitAnalysis(LoopAccessReport() << "cannot identify array bounds");
DEBUG(dbgs() << "LAA: We can't vectorize because we can't find " <<
"the array bounds.\n");
@@ -1154,17 +1155,10 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
CanDoRT = Accesses.canCheckPtrAtRT(PtrRtCheck, NumComparisons, SE,
TheLoop, Strides, true);
- // Check that we did not collect too many pointers or found an unsizeable
- // pointer.
- if (!CanDoRT || NumComparisons > RuntimeMemoryCheckThreshold) {
- if (!CanDoRT && NumComparisons > 0)
- emitAnalysis(LoopAccessReport()
- << "cannot check memory dependencies at runtime");
- else
- emitAnalysis(LoopAccessReport()
- << NumComparisons << " exceeds limit of "
- << RuntimeMemoryCheckThreshold
- << " dependent memory operations checked at runtime");
+ // Check that we found the bounds for the pointer.
+ if (!CanDoRT && NumComparisons > 0) {
+ emitAnalysis(LoopAccessReport()
+ << "cannot check memory dependencies at runtime");
DEBUG(dbgs() << "LAA: Can't vectorize with memory checks\n");
PtrRtCheck.reset();
CanVecMem = false;
@@ -1175,12 +1169,15 @@ void LoopAccessInfo::analyzeLoop(const ValueToValueMap &Strides) {
}
}
- if (!CanVecMem)
+ if (CanVecMem)
+ DEBUG(dbgs() << "LAA: No unsafe dependent memory operations in loop. We"
+ << (NeedRTCheck ? "" : " don't")
+ << " need a runtime memory check.\n");
+ else {
emitAnalysis(LoopAccessReport() <<
"unsafe dependent memory operations in loop");
-
- DEBUG(dbgs() << "LAA: We" << (NeedRTCheck ? "" : " don't") <<
- " need a runtime memory check.\n");
+ DEBUG(dbgs() << "LAA: unsafe dependent memory operations in loop\n");
+ }
}
bool LoopAccessInfo::blockNeedsPredication(BasicBlock *BB, Loop *TheLoop,
@@ -1212,8 +1209,8 @@ static Instruction *getFirstInst(Instruction *FirstInst, Value *V,
return nullptr;
}
-std::pair<Instruction *, Instruction *>
-LoopAccessInfo::addRuntimeCheck(Instruction *Loc) const {
+std::pair<Instruction *, Instruction *> LoopAccessInfo::addRuntimeCheck(
+ Instruction *Loc, const SmallVectorImpl<int> *PtrPartition) const {
Instruction *tnullptr = nullptr;
if (!PtrRtCheck.Need)
return std::pair<Instruction *, Instruction *>(tnullptr, tnullptr);
@@ -1223,7 +1220,7 @@ LoopAccessInfo::addRuntimeCheck(Instruction *Loc) const {
SmallVector<TrackingVH<Value> , 2> Ends;
LLVMContext &Ctx = Loc->getContext();
- SCEVExpander Exp(*SE, "induction");
+ SCEVExpander Exp(*SE, DL, "induction");
Instruction *FirstInst = nullptr;
for (unsigned i = 0; i < NumPointers; ++i) {
@@ -1254,7 +1251,7 @@ LoopAccessInfo::addRuntimeCheck(Instruction *Loc) const {
Value *MemoryRuntimeCheck = nullptr;
for (unsigned i = 0; i < NumPointers; ++i) {
for (unsigned j = i+1; j < NumPointers; ++j) {
- if (!PtrRtCheck.needsChecking(i, j))
+ if (!PtrRtCheck.needsChecking(i, j, PtrPartition))
continue;
unsigned AS0 = Starts[i]->getType()->getPointerAddressSpace();
@@ -1298,12 +1295,13 @@ LoopAccessInfo::addRuntimeCheck(Instruction *Loc) const {
}
LoopAccessInfo::LoopAccessInfo(Loop *L, ScalarEvolution *SE,
- const DataLayout *DL,
+ const DataLayout &DL,
const TargetLibraryInfo *TLI, AliasAnalysis *AA,
DominatorTree *DT,
const ValueToValueMap &Strides)
- : TheLoop(L), SE(SE), DL(DL), TLI(TLI), AA(AA), DT(DT), NumLoads(0),
- NumStores(0), MaxSafeDepDistBytes(-1U), CanVecMem(false) {
+ : DepChecker(SE, L), NumComparisons(0), TheLoop(L), SE(SE), DL(DL),
+ TLI(TLI), AA(AA), DT(DT), NumLoads(0), NumStores(0),
+ MaxSafeDepDistBytes(-1U), CanVecMem(false) {
if (canAnalyzeLoop())
analyzeLoop(Strides);
}
@@ -1319,7 +1317,14 @@ void LoopAccessInfo::print(raw_ostream &OS, unsigned Depth) const {
if (Report)
OS.indent(Depth) << "Report: " << Report->str() << "\n";
- // FIXME: Print unsafe dependences
+ if (auto *InterestingDependences = DepChecker.getInterestingDependences()) {
+ OS.indent(Depth) << "Interesting Dependences:\n";
+ for (auto &Dep : *InterestingDependences) {
+ Dep.print(OS, Depth + 2, DepChecker.getMemoryInstructions());
+ OS << "\n";
+ }
+ } else
+ OS.indent(Depth) << "Too many interesting dependences, not recorded\n";
// List the pair of accesses need run-time checks to prove independence.
PtrRtCheck.print(OS, Depth);
@@ -1336,6 +1341,7 @@ LoopAccessAnalysis::getInfo(Loop *L, const ValueToValueMap &Strides) {
#endif
if (!LAI) {
+ const DataLayout &DL = L->getHeader()->getModule()->getDataLayout();
LAI = llvm::make_unique<LoopAccessInfo>(L, SE, DL, TLI, AA, DT, Strides);
#ifndef NDEBUG
LAI->NumSymbolicStrides = Strides.size();
@@ -1360,7 +1366,6 @@ void LoopAccessAnalysis::print(raw_ostream &OS, const Module *M) const {
bool LoopAccessAnalysis::runOnFunction(Function &F) {
SE = &getAnalysis<ScalarEvolution>();
- DL = F.getParent()->getDataLayout();
auto *TLIP = getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>();
TLI = TLIP ? &TLIP->getTLI() : nullptr;
AA = &getAnalysis<AliasAnalysis>();
generated by cgit v1.1 at 2024-12-22 11:05:53 +0000