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Loop Vectorizer: Refactor code to compute vectorized memory instruction cost

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Introduce a helper class that computes the cost of memory access instructions.
No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174422 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Arnold Schwaighofer 2013-02-05 18:46:41 +00:00
parent f2c4db97e1
commit 7d80dad407
1 changed files with 178 additions and 79 deletions
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257
lib/Transforms/Vectorize/LoopVectorize.cpp
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@ -560,6 +560,11 @@ public:
/// \return information about the register usage of the loop.
RegisterUsage calculateRegisterUsage();
/// A helper function for converting Scalar types to vector types.
/// If the incoming type is void, we return void. If the VF is 1, we return
/// the scalar type.
static Type* ToVectorTy(Type *Scalar, unsigned VF);
private:
/// Returns the expected execution cost. The unit of the cost does
/// not matter because we use the 'cost' units to compare different
@ -571,11 +576,6 @@ private:
/// width. Vector width of one means scalar.
unsigned getInstructionCost(Instruction *I, unsigned VF);
/// A helper function for converting Scalar types to vector types.
/// If the incoming type is void, we return void. If the VF is 1, we return
/// the scalar type.
static Type* ToVectorTy(Type *Scalar, unsigned VF);
/// Returns whether the instruction is a load or store and will be a emitted
/// as a vector operation.
bool isConsecutiveLoadOrStore(Instruction *I);
@ -594,6 +594,177 @@ private:
DataLayout *DL;
};
/// A helper class to compute the cost of a memory operation (load or store).
class MemoryCostComputation {
public:
/// \brief This function computes the cost of a memory instruction, either of
/// a load or of a store.
/// \param Inst a pointer to a LoadInst or a StoreInst.
/// \param VF the vector factor to use.
/// \param TTI the target transform information used to obtain costs.
/// \param Legality the legality class used by this function to obtain the
/// access strid of the memory operation.
/// \returns the estimated cost of the memory instruction.
static unsigned computeCost(Value *Inst, unsigned VF,
const TargetTransformInfo &TTI,
LoopVectorizationLegality *Legality) {
if (StoreInst *Store = dyn_cast<StoreInst>(Inst))
return StoreCost(Store, VF, TTI, Legality).cost();
return LoadCost(cast<LoadInst>(Inst), VF, TTI, Legality).cost();
}
private:
/// An helper class to compute the cost of vectorize memory instruction. It is
/// subclassed by load and store cost computation classes who fill the fields
/// with values that require knowing about the concrete Load/StoreInst class.
class MemoryOpCost {
public:
/// \return the cost of vectorizing the memory access instruction.
unsigned cost() {
if (VectorFactor == 1)
return TTI.getMemoryOpCost(Opcode, VectorTy, Alignment, AddressSpace);
if ((Stride = Legality->isConsecutivePtr(PointerOperand)))
return costOfWideMemInst();
return costOfScalarizedMemInst();
}
protected:
/// The pointer operand of the memory instruction.
Value *PointerOperand;
/// The scalar type of the memory access.
Type *ScalarTy;
/// The vector type of the memory access.
Type *VectorTy;
/// The vector factor by which we vectorize.
unsigned VectorFactor;
/// The stride of the memory access.
int Stride;
/// The alignment of the memory operation.
unsigned Alignment;
/// The address space of the memory operation.
unsigned AddressSpace;
/// The opcode of the memory instruction.
unsigned Opcode;
/// Are we looking at a load or store instruction.
bool IsLoadInst;
const TargetTransformInfo &TTI;
LoopVectorizationLegality *Legality;
/// Constructs a helper class to compute the cost of a memory instruction.
/// \param VF the vector factor (the length of the vector).
/// \param TI the target transform information used by this class to obtain
/// costs.
/// \param L the legality class used by this class to obtain the access
/// stride of the memory operation.
MemoryOpCost(unsigned VF, const TargetTransformInfo &TI,
LoopVectorizationLegality *L) :
VectorFactor(VF), TTI(TI), Legality(L) {
}
private:
/// \return the cost if the memory instruction is scalarized.
unsigned costOfScalarizedMemInst() {
unsigned Cost = 0;
Cost += costOfExtractFromPointerVector();
Cost += costOfExtractFromValueVector();
Cost += VectorFactor * TTI.getMemoryOpCost(Opcode, ScalarTy, Alignment,
AddressSpace);
Cost += costOfInsertIntoValueVector();
return Cost;
}
/// \return the cost of extracting the pointers out of the pointer vector.
unsigned costOfExtractFromPointerVector() {
Type *PtrTy = getVectorizedPointerOperandType();
return costOfVectorInstForAllElems(Instruction::ExtractElement, PtrTy);
}
/// \return the cost for extracting values out of the value vector if the
/// memory instruction is a store and zero otherwise.
unsigned costOfExtractFromValueVector() {
if (IsLoadInst)
return 0;
return costOfVectorInstForAllElems(Instruction::ExtractElement, VectorTy);
}
/// \return the cost of insert values into the value vector if the memory
/// instruction was a load and zero otherwise.
unsigned costOfInsertIntoValueVector() {
if (!IsLoadInst)
return 0;
return costOfVectorInstForAllElems(Instruction::InsertElement, VectorTy);
}
/// \return the cost of a vector memory instruction.
unsigned costOfWideMemInst() {
unsigned Cost = TTI.getMemoryOpCost(Opcode, VectorTy, Alignment,
AddressSpace);
// Reverse stride.
if (Stride < 0)
Cost += TTI.getShuffleCost(TargetTransformInfo::SK_Reverse, VectorTy,
0);
return Cost;
}
/// Helper function to compute the cost of one insert- or extractelement
/// instruction per vector element.
/// \param VecOpcode the vector instruction opcode (Can be either
/// InsertElement or an ExtractElement).
/// \param Ty the vector type the vector instruction operates on.
/// \return the cost of an vector instruction applied to each vector
/// element.
unsigned costOfVectorInstForAllElems(unsigned VecOpcode, Type *Ty) {
unsigned Cost = 0;
for (unsigned i = 0; i < VectorFactor; ++i)
Cost += TTI.getVectorInstrCost(VecOpcode, Ty, i);
return Cost;
}
/// \return a vectorized type for the pointer operand.
Type * getVectorizedPointerOperandType() {
Type *PointerOpTy = PointerOperand->getType();
return LoopVectorizationCostModel::ToVectorTy(PointerOpTy, VectorFactor);
}
};
/// Implementation of the abstract memory cost base class. Sets field of base
/// class whose value depends on the LoadInst.
class LoadCost : public MemoryOpCost {
public:
LoadCost(LoadInst *Load, unsigned VF, const TargetTransformInfo &TI,
LoopVectorizationLegality *L) : MemoryOpCost(VF, TI, L) {
PointerOperand = Load->getPointerOperand();
ScalarTy = Load->getType();
VectorTy = LoopVectorizationCostModel::ToVectorTy(ScalarTy, VF);
Alignment = Load->getAlignment();
AddressSpace = Load->getPointerAddressSpace();
Opcode = Load->getOpcode();
IsLoadInst = true;
}
};
/// Implementation of the abstract memory cost base class. Sets field of base
/// class whose value depends on the StoreInst.
class StoreCost : public MemoryOpCost {
public:
StoreCost(StoreInst *Store, unsigned VF, const TargetTransformInfo &TI,
LoopVectorizationLegality *L) : MemoryOpCost(VF, TI, L) {
PointerOperand = Store->getPointerOperand();
ScalarTy = Store->getValueOperand()->getType();
VectorTy = LoopVectorizationCostModel::ToVectorTy(ScalarTy, VF);
Alignment = Store->getAlignment();
AddressSpace = Store->getPointerAddressSpace();
Opcode = Store->getOpcode();
IsLoadInst = false;
}
};
};
/// The LoopVectorize Pass.
struct LoopVectorize : public LoopPass {
/// Pass identification, replacement for typeid
@ -3097,83 +3268,11 @@ LoopVectorizationCostModel::getInstructionCost(Instruction *I, unsigned VF) {
VectorTy = ToVectorTy(ValTy, VF);
return TTI.getCmpSelInstrCost(I->getOpcode(), VectorTy);
}
case Instruction::Load:
case Instruction::Store: {
StoreInst *SI = cast<StoreInst>(I);
Type *ValTy = SI->getValueOperand()->getType();
VectorTy = ToVectorTy(ValTy, VF);
if (VF == 1)
return TTI.getMemoryOpCost(I->getOpcode(), VectorTy,
SI->getAlignment(),
SI->getPointerAddressSpace());
// Scalarized stores.
int Stride = Legal->isConsecutivePtr(SI->getPointerOperand());
bool Reverse = Stride < 0;
if (0 == Stride) {
unsigned Cost = 0;
// The cost of extracting from the value vector and pointer vector.
Type *PtrTy = ToVectorTy(I->getOperand(0)->getType(), VF);
for (unsigned i = 0; i < VF; ++i) {
Cost += TTI.getVectorInstrCost(Instruction::ExtractElement, VectorTy,
i);
Cost += TTI.getVectorInstrCost(Instruction::ExtractElement, PtrTy, i);
}
// The cost of the scalar stores.
Cost += VF * TTI.getMemoryOpCost(I->getOpcode(), ValTy->getScalarType(),
SI->getAlignment(),
SI->getPointerAddressSpace());
return Cost;
}
// Wide stores.
unsigned Cost = TTI.getMemoryOpCost(I->getOpcode(), VectorTy,
SI->getAlignment(),
SI->getPointerAddressSpace());
if (Reverse)
Cost += TTI.getShuffleCost(TargetTransformInfo::SK_Reverse,
VectorTy, 0);
return Cost;
return MemoryCostComputation::computeCost(I, VF, TTI, Legal);
}
case Instruction::Load: {
LoadInst *LI = cast<LoadInst>(I);
if (VF == 1)
return TTI.getMemoryOpCost(I->getOpcode(), VectorTy, LI->getAlignment(),
LI->getPointerAddressSpace());
// Scalarized loads.
int Stride = Legal->isConsecutivePtr(LI->getPointerOperand());
bool Reverse = Stride < 0;
if (0 == Stride) {
unsigned Cost = 0;
Type *PtrTy = ToVectorTy(I->getOperand(0)->getType(), VF);
// The cost of extracting from the pointer vector.
for (unsigned i = 0; i < VF; ++i)
Cost += TTI.getVectorInstrCost(Instruction::ExtractElement, PtrTy, i);
// The cost of inserting data to the result vector.
for (unsigned i = 0; i < VF; ++i)
Cost += TTI.getVectorInstrCost(Instruction::InsertElement, VectorTy, i);
// The cost of the scalar stores.
Cost += VF * TTI.getMemoryOpCost(I->getOpcode(), RetTy->getScalarType(),
LI->getAlignment(),
LI->getPointerAddressSpace());
return Cost;
}
// Wide loads.
unsigned Cost = TTI.getMemoryOpCost(I->getOpcode(), VectorTy,
LI->getAlignment(),
LI->getPointerAddressSpace());
if (Reverse)
Cost += TTI.getShuffleCost(TargetTransformInfo::SK_Reverse, VectorTy, 0);
return Cost;
}
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPToUI: