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[LoopVectorize] Extract InductionInfo into a helper class... 

... and move it into LoopUtils where it can be used by other passes, just like ReductionDescriptor. The API is very similar to ReductionDescriptor - that is, not very nice at all. Sorting these both out will come in a followup.

NFC

llvm-svn: 246145
This commit is contained in:
James Molloy 2015-08-27 09:53:00 +00:00
parent 2d1ed0bfa7
commit 1bbf15c57c
4 changed files with 135 additions and 139 deletions
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53
llvm/include/llvm/Transforms/Utils/LoopUtils.h
View File

@ -198,6 +198,54 @@ private:
Instruction *UnsafeAlgebraInst;
};
/// A struct for saving information about induction variables.
class InductionDescriptor {
public:
/// This enum represents the kinds of inductions that we support.
enum InductionKind {
IK_NoInduction, ///< Not an induction variable.
IK_IntInduction, ///< Integer induction variable. Step = C.
IK_PtrInduction ///< Pointer induction var. Step = C / sizeof(elem).
};
private:
/// Private constructor - use \c isInductionPHI.
InductionDescriptor(Value *Start, InductionKind K, ConstantInt *Step);
public:
/// Default constructor - creates an invalid induction.
InductionDescriptor()
: StartValue(nullptr), IK(IK_NoInduction), StepValue(nullptr) {}
/// Get the consecutive direction. Returns:
/// 0 - unknown or non-consecutive.
/// 1 - consecutive and increasing.
/// -1 - consecutive and decreasing.
int getConsecutiveDirection() const;
/// Compute the transformed value of Index at offset StartValue using step
/// StepValue.
/// For integer induction, returns StartValue + Index * StepValue.
/// For pointer induction, returns StartValue[Index * StepValue].
/// FIXME: The newly created binary instructions should contain nsw/nuw
/// flags, which can be found from the original scalar operations.
Value *transform(IRBuilder<> &B, Value *Index) const;
Value *getStartValue() const { return StartValue; }
InductionKind getKind() const { return IK; }
ConstantInt *getStepValue() const { return StepValue; }
static bool isInductionPHI(PHINode *Phi, ScalarEvolution *SE,
InductionDescriptor &D);
private:
/// Start value.
TrackingVH<Value> StartValue;
/// Induction kind.
InductionKind IK;
/// Step value.
ConstantInt *StepValue;
};
BasicBlock *InsertPreheaderForLoop(Loop *L, Pass *P);
/// \brief Simplify each loop in a loop nest recursively.
@ -277,11 +325,6 @@ bool promoteLoopAccessesToScalars(AliasSet &, SmallVectorImpl<BasicBlock*> &,
/// Updates safety information in LICMSafetyInfo argument.
void computeLICMSafetyInfo(LICMSafetyInfo *, Loop *);
/// \brief Checks if the given PHINode in a loop header is an induction
/// variable. Returns true if this is an induction PHI along with the step
/// value.
bool isInductionPHI(PHINode *, ScalarEvolution *, ConstantInt *&);
/// \brief Returns the instructions that use values defined in the loop.
SmallVector<Instruction *, 8> findDefsUsedOutsideOfLoop(Loop *L);
}

4
llvm/lib/Transforms/Scalar/LoopInterchange.cpp
View File

@ -698,9 +698,9 @@ bool LoopInterchangeLegality::findInductionAndReductions(
return false;
for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I) {
RecurrenceDescriptor RD;
InductionDescriptor ID;
PHINode *PHI = cast<PHINode>(I);
ConstantInt *StepValue = nullptr;
if (isInductionPHI(PHI, SE, StepValue))
if (InductionDescriptor::isInductionPHI(PHI, SE, ID))
Inductions.push_back(PHI);
else if (RecurrenceDescriptor::isReductionPHI(PHI, L, RD))
Reductions.push_back(PHI);

60
llvm/lib/Transforms/Utils/LoopUtils.cpp
View File

@ -456,8 +456,54 @@ Value *RecurrenceDescriptor::createMinMaxOp(IRBuilder<> &Builder,
return Select;
}
bool llvm::isInductionPHI(PHINode *Phi, ScalarEvolution *SE,
ConstantInt *&StepValue) {
InductionDescriptor::InductionDescriptor(Value *Start, InductionKind K,
ConstantInt *Step)
: StartValue(Start), IK(K), StepValue(Step) {
assert(IK != IK_NoInduction && "Not an induction");
assert(StartValue && "StartValue is null");
assert(StepValue && !StepValue->isZero() && "StepValue is zero");
assert((IK != IK_PtrInduction || StartValue->getType()->isPointerTy()) &&
"StartValue is not a pointer for pointer induction");
assert((IK != IK_IntInduction || StartValue->getType()->isIntegerTy()) &&
"StartValue is not an integer for integer induction");
assert(StepValue->getType()->isIntegerTy() &&
"StepValue is not an integer");
}
int InductionDescriptor::getConsecutiveDirection() const {
if (StepValue && (StepValue->isOne() || StepValue->isMinusOne()))
return StepValue->getSExtValue();
return 0;
}
Value *InductionDescriptor::transform(IRBuilder<> &B, Value *Index) const {
switch (IK) {
case IK_IntInduction:
assert(Index->getType() == StartValue->getType() &&
"Index type does not match StartValue type");
if (StepValue->isMinusOne())
return B.CreateSub(StartValue, Index);
if (!StepValue->isOne())
Index = B.CreateMul(Index, StepValue);
return B.CreateAdd(StartValue, Index);
case IK_PtrInduction:
assert(Index->getType() == StepValue->getType() &&
"Index type does not match StepValue type");
if (StepValue->isMinusOne())
Index = B.CreateNeg(Index);
else if (!StepValue->isOne())
Index = B.CreateMul(Index, StepValue);
return B.CreateGEP(nullptr, StartValue, Index);
case IK_NoInduction:
return nullptr;
}
llvm_unreachable("invalid enum");
}
bool InductionDescriptor::isInductionPHI(PHINode *Phi, ScalarEvolution *SE,
InductionDescriptor &D) {
Type *PhiTy = Phi->getType();
// We only handle integer and pointer inductions variables.
if (!PhiTy->isIntegerTy() && !PhiTy->isPointerTy())
@ -471,6 +517,10 @@ bool llvm::isInductionPHI(PHINode *Phi, ScalarEvolution *SE,
return false;
}
assert(AR->getLoop()->getHeader() == Phi->getParent() &&
"PHI is an AddRec for a different loop?!");
Value *StartValue =
Phi->getIncomingValueForBlock(AR->getLoop()->getLoopPreheader());
const SCEV *Step = AR->getStepRecurrence(*SE);
// Calculate the pointer stride and check if it is consecutive.
const SCEVConstant *C = dyn_cast<SCEVConstant>(Step);
@ -479,7 +529,7 @@ bool llvm::isInductionPHI(PHINode *Phi, ScalarEvolution *SE,
ConstantInt *CV = C->getValue();
if (PhiTy->isIntegerTy()) {
StepValue = CV;
D = InductionDescriptor(StartValue, IK_IntInduction, CV);
return true;
}
@ -498,7 +548,9 @@ bool llvm::isInductionPHI(PHINode *Phi, ScalarEvolution *SE,
int64_t CVSize = CV->getSExtValue();
if (CVSize % Size)
return false;
StepValue = ConstantInt::getSigned(CV->getType(), CVSize / Size);
auto *StepValue = ConstantInt::getSigned(CV->getType(), CVSize / Size);
D = InductionDescriptor(StartValue, IK_PtrInduction, StepValue);
return true;
}

157
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
View File

@ -1095,87 +1095,13 @@ public:
Induction(nullptr), WidestIndTy(nullptr), HasFunNoNaNAttr(false),
Requirements(R), Hints(H) {}
/// This enum represents the kinds of inductions that we support.
enum InductionKind {
IK_NoInduction, ///< Not an induction variable.
IK_IntInduction, ///< Integer induction variable. Step = C.
IK_PtrInduction ///< Pointer induction var. Step = C / sizeof(elem).
};
/// A struct for saving information about induction variables.
struct InductionInfo {
InductionInfo(Value *Start, InductionKind K, ConstantInt *Step)
: StartValue(Start), IK(K), StepValue(Step) {
assert(IK != IK_NoInduction && "Not an induction");
assert(StartValue && "StartValue is null");
assert(StepValue && !StepValue->isZero() && "StepValue is zero");
assert((IK != IK_PtrInduction || StartValue->getType()->isPointerTy()) &&
"StartValue is not a pointer for pointer induction");
assert((IK != IK_IntInduction || StartValue->getType()->isIntegerTy()) &&
"StartValue is not an integer for integer induction");
assert(StepValue->getType()->isIntegerTy() &&
"StepValue is not an integer");
}
InductionInfo()
: StartValue(nullptr), IK(IK_NoInduction), StepValue(nullptr) {}
/// Get the consecutive direction. Returns:
/// 0 - unknown or non-consecutive.
/// 1 - consecutive and increasing.
/// -1 - consecutive and decreasing.
int getConsecutiveDirection() const {
if (StepValue && (StepValue->isOne() || StepValue->isMinusOne()))
return StepValue->getSExtValue();
return 0;
}
/// Compute the transformed value of Index at offset StartValue using step
/// StepValue.
/// For integer induction, returns StartValue + Index * StepValue.
/// For pointer induction, returns StartValue[Index * StepValue].
/// FIXME: The newly created binary instructions should contain nsw/nuw
/// flags, which can be found from the original scalar operations.
Value *transform(IRBuilder<> &B, Value *Index) const {
switch (IK) {
case IK_IntInduction:
assert(Index->getType() == StartValue->getType() &&
"Index type does not match StartValue type");
if (StepValue->isMinusOne())
return B.CreateSub(StartValue, Index);
if (!StepValue->isOne())
Index = B.CreateMul(Index, StepValue);
return B.CreateAdd(StartValue, Index);
case IK_PtrInduction:
assert(Index->getType() == StepValue->getType() &&
"Index type does not match StepValue type");
if (StepValue->isMinusOne())
Index = B.CreateNeg(Index);
else if (!StepValue->isOne())
Index = B.CreateMul(Index, StepValue);
return B.CreateGEP(nullptr, StartValue, Index);
case IK_NoInduction:
return nullptr;
}
llvm_unreachable("invalid enum");
}
/// Start value.
TrackingVH<Value> StartValue;
/// Induction kind.
InductionKind IK;
/// Step value.
ConstantInt *StepValue;
};
/// ReductionList contains the reduction descriptors for all
/// of the reductions that were found in the loop.
typedef DenseMap<PHINode *, RecurrenceDescriptor> ReductionList;
/// InductionList saves induction variables and maps them to the
/// induction descriptor.
typedef MapVector<PHINode*, InductionInfo> InductionList;
typedef MapVector<PHINode*, InductionDescriptor> InductionList;
/// Returns true if it is legal to vectorize this loop.
/// This does not mean that it is profitable to vectorize this
@ -1293,10 +1219,6 @@ private:
/// and we know that we can read from them without segfault.
bool blockCanBePredicated(BasicBlock *BB, SmallPtrSetImpl<Value *> &SafePtrs);
/// Returns the induction kind of Phi and record the step. This function may
/// return NoInduction if the PHI is not an induction variable.
InductionKind isInductionVariable(PHINode *Phi, ConstantInt *&StepValue);
/// \brief Collect memory access with loop invariant strides.
///
/// Looks for accesses like "a[i * StrideA]" where "StrideA" is loop
@ -1946,7 +1868,7 @@ int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
// If this value is a pointer induction variable we know it is consecutive.
PHINode *Phi = dyn_cast_or_null<PHINode>(Ptr);
if (Phi && Inductions.count(Phi)) {
InductionInfo II = Inductions[Phi];
InductionDescriptor II = Inductions[Phi];
return II.getConsecutiveDirection();
}
@ -1971,7 +1893,7 @@ int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
if (!SE->isLoopInvariant(SE->getSCEV(Gep->getOperand(i)), TheLoop))
return 0;
InductionInfo II = Inductions[Phi];
InductionDescriptor II = Inductions[Phi];
return II.getConsecutiveDirection();
}
@ -2878,7 +2800,7 @@ void InnerLoopVectorizer::createEmptyLoop() {
BypassBuilder.SetInsertPoint(LoopBypassBlocks.back()->getTerminator());
for (I = List->begin(), E = List->end(); I != E; ++I) {
PHINode *OrigPhi = I->first;
LoopVectorizationLegality::InductionInfo II = I->second;
InductionDescriptor II = I->second;
Type *ResumeValTy = (OrigPhi == OldInduction) ? IdxTy : OrigPhi->getType();
PHINode *ResumeVal = PHINode::Create(ResumeValTy, 2, "resume.val",
@ -2903,10 +2825,10 @@ void InnerLoopVectorizer::createEmptyLoop() {
}
Value *EndValue = nullptr;
switch (II.IK) {
case LoopVectorizationLegality::IK_NoInduction:
switch (II.getKind()) {
case InductionDescriptor::IK_NoInduction:
llvm_unreachable("Unknown induction");
case LoopVectorizationLegality::IK_IntInduction: {
case InductionDescriptor::IK_IntInduction: {
// Handle the integer induction counter.
assert(OrigPhi->getType()->isIntegerTy() && "Invalid type");
@ -2919,10 +2841,10 @@ void InnerLoopVectorizer::createEmptyLoop() {
// The new PHI merges the original incoming value, in case of a bypass,
// or the value at the end of the vectorized loop.
for (unsigned I = 1, E = LoopBypassBlocks.size(); I != E; ++I)
TruncResumeVal->addIncoming(II.StartValue, LoopBypassBlocks[I]);
TruncResumeVal->addIncoming(II.getStartValue(), LoopBypassBlocks[I]);
TruncResumeVal->addIncoming(EndValue, VecBody);
BCTruncResumeVal->addIncoming(II.StartValue, LoopBypassBlocks[0]);
BCTruncResumeVal->addIncoming(II.getStartValue(), LoopBypassBlocks[0]);
// We know what the end value is.
EndValue = IdxEndRoundDown;
@ -2934,15 +2856,15 @@ void InnerLoopVectorizer::createEmptyLoop() {
// Not the canonical induction variable - add the vector loop count to the
// start value.
Value *CRD = BypassBuilder.CreateSExtOrTrunc(CountRoundDown,
II.StartValue->getType(),
II.getStartValue()->getType(),
"cast.crd");
EndValue = II.transform(BypassBuilder, CRD);
EndValue->setName("ind.end");
break;
}
case LoopVectorizationLegality::IK_PtrInduction: {
case InductionDescriptor::IK_PtrInduction: {
Value *CRD = BypassBuilder.CreateSExtOrTrunc(CountRoundDown,
II.StepValue->getType(),
II.getStepValue()->getType(),
"cast.crd");
EndValue = II.transform(BypassBuilder, CRD);
EndValue->setName("ptr.ind.end");
@ -2956,7 +2878,7 @@ void InnerLoopVectorizer::createEmptyLoop() {
if (OrigPhi == OldInduction)
ResumeVal->addIncoming(StartIdx, LoopBypassBlocks[I]);
else
ResumeVal->addIncoming(II.StartValue, LoopBypassBlocks[I]);
ResumeVal->addIncoming(II.getStartValue(), LoopBypassBlocks[I]);
}
ResumeVal->addIncoming(EndValue, VecBody);
@ -2969,7 +2891,7 @@ void InnerLoopVectorizer::createEmptyLoop() {
BCResumeVal->addIncoming(StartIdx, LoopBypassBlocks[0]);
OrigPhi->setIncomingValue(BlockIdx, BCTruncResumeVal);
} else {
BCResumeVal->addIncoming(II.StartValue, LoopBypassBlocks[0]);
BCResumeVal->addIncoming(II.getStartValue(), LoopBypassBlocks[0]);
OrigPhi->setIncomingValue(BlockIdx, BCResumeVal);
}
}
@ -3554,16 +3476,15 @@ void InnerLoopVectorizer::widenPHIInstruction(Instruction *PN,
assert(Legal->getInductionVars()->count(P) &&
"Not an induction variable");
LoopVectorizationLegality::InductionInfo II =
Legal->getInductionVars()->lookup(P);
InductionDescriptor II = Legal->getInductionVars()->lookup(P);
// FIXME: The newly created binary instructions should contain nsw/nuw flags,
// which can be found from the original scalar operations.
switch (II.IK) {
case LoopVectorizationLegality::IK_NoInduction:
switch (II.getKind()) {
case InductionDescriptor::IK_NoInduction:
llvm_unreachable("Unknown induction");
case LoopVectorizationLegality::IK_IntInduction: {
assert(P->getType() == II.StartValue->getType() && "Types must match");
case InductionDescriptor::IK_IntInduction: {
assert(P->getType() == II.getStartValue()->getType() && "Types must match");
Type *PhiTy = P->getType();
Value *Broadcasted;
if (P == OldInduction) {
@ -3583,17 +3504,17 @@ void InnerLoopVectorizer::widenPHIInstruction(Instruction *PN,
// After broadcasting the induction variable we need to make the vector
// consecutive by adding 0, 1, 2, etc.
for (unsigned part = 0; part < UF; ++part)
Entry[part] = getStepVector(Broadcasted, VF * part, II.StepValue);
Entry[part] = getStepVector(Broadcasted, VF * part, II.getStepValue());
return;
}
case LoopVectorizationLegality::IK_PtrInduction:
case InductionDescriptor::IK_PtrInduction:
// Handle the pointer induction variable case.
assert(P->getType()->isPointerTy() && "Unexpected type.");
// This is the normalized GEP that starts counting at zero.
Value *NormalizedIdx =
Builder.CreateSub(Induction, ExtendedIdx, "normalized.idx");
NormalizedIdx =
Builder.CreateSExtOrTrunc(NormalizedIdx, II.StepValue->getType());
Builder.CreateSExtOrTrunc(NormalizedIdx, II.getStepValue()->getType());
// This is the vector of results. Notice that we don't generate
// vector geps because scalar geps result in better code.
for (unsigned part = 0; part < UF; ++part) {
@ -3754,10 +3675,9 @@ void InnerLoopVectorizer::vectorizeBlockInLoop(BasicBlock *BB, PhiVector *PV) {
Value *ScalarCast = Builder.CreateCast(CI->getOpcode(), Induction,
CI->getType());
Value *Broadcasted = getBroadcastInstrs(ScalarCast);
LoopVectorizationLegality::InductionInfo II =
Legal->getInductionVars()->lookup(OldInduction);
InductionDescriptor II = Legal->getInductionVars()->lookup(OldInduction);
Constant *Step =
ConstantInt::getSigned(CI->getType(), II.StepValue->getSExtValue());
ConstantInt::getSigned(CI->getType(), II.getStepValue()->getSExtValue());
for (unsigned Part = 0; Part < UF; ++Part)
Entry[Part] = getStepVector(Broadcasted, VF * Part, Step);
propagateMetadata(Entry, it);
@ -4104,7 +4024,6 @@ static bool hasOutsideLoopUser(const Loop *TheLoop, Instruction *Inst,
}
bool LoopVectorizationLegality::canVectorizeInstrs() {
BasicBlock *PreHeader = TheLoop->getLoopPreheader();
BasicBlock *Header = TheLoop->getHeader();
// Look for the attribute signaling the absence of NaNs.
@ -4156,13 +4075,9 @@ bool LoopVectorizationLegality::canVectorizeInstrs() {
return false;
}
// This is the value coming from the preheader.
Value *StartValue = Phi->getIncomingValueForBlock(PreHeader);
ConstantInt *StepValue = nullptr;
// Check if this is an induction variable.
InductionKind IK = isInductionVariable(Phi, StepValue);
if (IK_NoInduction != IK) {
InductionDescriptor ID;
if (InductionDescriptor::isInductionPHI(Phi, SE, ID)) {
Inductions[Phi] = ID;
// Get the widest type.
if (!WidestIndTy)
WidestIndTy = convertPointerToIntegerType(DL, PhiTy);
@ -4170,7 +4085,8 @@ bool LoopVectorizationLegality::canVectorizeInstrs() {
WidestIndTy = getWiderType(DL, PhiTy, WidestIndTy);
// Int inductions are special because we only allow one IV.
if (IK == IK_IntInduction && StepValue->isOne()) {
if (ID.getKind() == InductionDescriptor::IK_IntInduction &&
ID.getStepValue()->isOne()) {
// Use the phi node with the widest type as induction. Use the last
// one if there are multiple (no good reason for doing this other
// than it is expedient).
@ -4179,7 +4095,6 @@ bool LoopVectorizationLegality::canVectorizeInstrs() {
}
DEBUG(dbgs() << "LV: Found an induction variable.\n");
Inductions[Phi] = InductionInfo(StartValue, IK, StepValue);
// Until we explicitly handle the case of an induction variable with
// an outside loop user we have to give up vectorizing this loop.
@ -4362,20 +4277,6 @@ bool LoopVectorizationLegality::canVectorizeMemory() {
return true;
}
LoopVectorizationLegality::InductionKind
LoopVectorizationLegality::isInductionVariable(PHINode *Phi,
ConstantInt *&StepValue) {
if (!isInductionPHI(Phi, SE, StepValue))
return IK_NoInduction;
Type *PhiTy = Phi->getType();
// Found an Integer induction variable.
if (PhiTy->isIntegerTy())
return IK_IntInduction;
// Found an Pointer induction variable.
return IK_PtrInduction;
}
bool LoopVectorizationLegality::isInductionVariable(const Value *V) {
Value *In0 = const_cast<Value*>(V);
PHINode *PN = dyn_cast_or_null<PHINode>(In0);