diff options
Diffstat (limited to 'lib/Transforms/InstCombine/InstructionCombining.cpp')
| -rw-r--r-- | lib/Transforms/InstCombine/InstructionCombining.cpp | 540 |
1 files changed, 0 insertions, 540 deletions
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp index f9baffcf46..a26e671494 100644 --- a/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -7252,546 +7252,6 @@ Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) { return 0; } -/// CheapToScalarize - Return true if the value is cheaper to scalarize than it -/// is to leave as a vector operation. -static bool CheapToScalarize(Value *V, bool isConstant) { - if (isa<ConstantAggregateZero>(V)) - return true; - if (ConstantVector *C = dyn_cast<ConstantVector>(V)) { - if (isConstant) return true; - // If all elts are the same, we can extract. - Constant *Op0 = C->getOperand(0); - for (unsigned i = 1; i < C->getNumOperands(); ++i) - if (C->getOperand(i) != Op0) - return false; - return true; - } - Instruction *I = dyn_cast<Instruction>(V); - if (!I) return false; - - // Insert element gets simplified to the inserted element or is deleted if - // this is constant idx extract element and its a constant idx insertelt. - if (I->getOpcode() == Instruction::InsertElement && isConstant && - isa<ConstantInt>(I->getOperand(2))) - return true; - if (I->getOpcode() == Instruction::Load && I->hasOneUse()) - return true; - if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) - if (BO->hasOneUse() && - (CheapToScalarize(BO->getOperand(0), isConstant) || - CheapToScalarize(BO->getOperand(1), isConstant))) - return true; - if (CmpInst *CI = dyn_cast<CmpInst>(I)) - if (CI->hasOneUse() && - (CheapToScalarize(CI->getOperand(0), isConstant) || - CheapToScalarize(CI->getOperand(1), isConstant))) - return true; - - return false; -} - -/// Read and decode a shufflevector mask. -/// -/// It turns undef elements into values that are larger than the number of -/// elements in the input. -static std::vector<unsigned> getShuffleMask(const ShuffleVectorInst *SVI) { - unsigned NElts = SVI->getType()->getNumElements(); - if (isa<ConstantAggregateZero>(SVI->getOperand(2))) - return std::vector<unsigned>(NElts, 0); - if (isa<UndefValue>(SVI->getOperand(2))) - return std::vector<unsigned>(NElts, 2*NElts); - - std::vector<unsigned> Result; - const ConstantVector *CP = cast<ConstantVector>(SVI->getOperand(2)); - for (User::const_op_iterator i = CP->op_begin(), e = CP->op_end(); i!=e; ++i) - if (isa<UndefValue>(*i)) - Result.push_back(NElts*2); // undef -> 8 - else - Result.push_back(cast<ConstantInt>(*i)->getZExtValue()); - return Result; -} - -/// FindScalarElement - Given a vector and an element number, see if the scalar -/// value is already around as a register, for example if it were inserted then -/// extracted from the vector. -static Value *FindScalarElement(Value *V, unsigned EltNo) { - assert(isa<VectorType>(V->getType()) && "Not looking at a vector?"); - const VectorType *PTy = cast<VectorType>(V->getType()); - unsigned Width = PTy->getNumElements(); - if (EltNo >= Width) // Out of range access. - return UndefValue::get(PTy->getElementType()); - - if (isa<UndefValue>(V)) - return UndefValue::get(PTy->getElementType()); - else if (isa<ConstantAggregateZero>(V)) - return Constant::getNullValue(PTy->getElementType()); - else if (ConstantVector *CP = dyn_cast<ConstantVector>(V)) - return CP->getOperand(EltNo); - else if (InsertElementInst *III = dyn_cast<InsertElementInst>(V)) { - // If this is an insert to a variable element, we don't know what it is. - if (!isa<ConstantInt>(III->getOperand(2))) - return 0; - unsigned IIElt = cast<ConstantInt>(III->getOperand(2))->getZExtValue(); - - // If this is an insert to the element we are looking for, return the - // inserted value. - if (EltNo == IIElt) - return III->getOperand(1); - - // Otherwise, the insertelement doesn't modify the value, recurse on its - // vector input. - return FindScalarElement(III->getOperand(0), EltNo); - } else if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V)) { - unsigned LHSWidth = - cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements(); - unsigned InEl = getShuffleMask(SVI)[EltNo]; - if (InEl < LHSWidth) - return FindScalarElement(SVI->getOperand(0), InEl); - else if (InEl < LHSWidth*2) - return FindScalarElement(SVI->getOperand(1), InEl - LHSWidth); - else - return UndefValue::get(PTy->getElementType()); - } - - // Otherwise, we don't know. - return 0; -} - -Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) { - // If vector val is undef, replace extract with scalar undef. - if (isa<UndefValue>(EI.getOperand(0))) - return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType())); - - // If vector val is constant 0, replace extract with scalar 0. - if (isa<ConstantAggregateZero>(EI.getOperand(0))) - return ReplaceInstUsesWith(EI, Constant::getNullValue(EI.getType())); - - if (ConstantVector *C = dyn_cast<ConstantVector>(EI.getOperand(0))) { - // If vector val is constant with all elements the same, replace EI with - // that element. When the elements are not identical, we cannot replace yet - // (we do that below, but only when the index is constant). - Constant *op0 = C->getOperand(0); - for (unsigned i = 1; i != C->getNumOperands(); ++i) - if (C->getOperand(i) != op0) { - op0 = 0; - break; - } - if (op0) - return ReplaceInstUsesWith(EI, op0); - } - - // If extracting a specified index from the vector, see if we can recursively - // find a previously computed scalar that was inserted into the vector. - if (ConstantInt *IdxC = dyn_cast<ConstantInt>(EI.getOperand(1))) { - unsigned IndexVal = IdxC->getZExtValue(); - unsigned VectorWidth = EI.getVectorOperandType()->getNumElements(); - - // If this is extracting an invalid index, turn this into undef, to avoid - // crashing the code below. - if (IndexVal >= VectorWidth) - return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType())); - - // This instruction only demands the single element from the input vector. - // If the input vector has a single use, simplify it based on this use - // property. - if (EI.getOperand(0)->hasOneUse() && VectorWidth != 1) { - APInt UndefElts(VectorWidth, 0); - APInt DemandedMask(VectorWidth, 1 << IndexVal); - if (Value *V = SimplifyDemandedVectorElts(EI.getOperand(0), - DemandedMask, UndefElts)) { - EI.setOperand(0, V); - return &EI; - } - } - - if (Value *Elt = FindScalarElement(EI.getOperand(0), IndexVal)) - return ReplaceInstUsesWith(EI, Elt); - - // If the this extractelement is directly using a bitcast from a vector of - // the same number of elements, see if we can find the source element from - // it. In this case, we will end up needing to bitcast the scalars. - if (BitCastInst *BCI = dyn_cast<BitCastInst>(EI.getOperand(0))) { - if (const VectorType *VT = - dyn_cast<VectorType>(BCI->getOperand(0)->getType())) - if (VT->getNumElements() == VectorWidth) - if (Value *Elt = FindScalarElement(BCI->getOperand(0), IndexVal)) - return new BitCastInst(Elt, EI.getType()); - } - } - - if (Instruction *I = dyn_cast<Instruction>(EI.getOperand(0))) { - // Push extractelement into predecessor operation if legal and - // profitable to do so - if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) { - if (I->hasOneUse() && - CheapToScalarize(BO, isa<ConstantInt>(EI.getOperand(1)))) { - Value *newEI0 = - Builder->CreateExtractElement(BO->getOperand(0), EI.getOperand(1), - EI.getName()+".lhs"); - Value *newEI1 = - Builder->CreateExtractElement(BO->getOperand(1), EI.getOperand(1), - EI.getName()+".rhs"); - return BinaryOperator::Create(BO->getOpcode(), newEI0, newEI1); - } - } else if (InsertElementInst *IE = dyn_cast<InsertElementInst>(I)) { - // Extracting the inserted element? - if (IE->getOperand(2) == EI.getOperand(1)) - return ReplaceInstUsesWith(EI, IE->getOperand(1)); - // If the inserted and extracted elements are constants, they must not - // be the same value, extract from the pre-inserted value instead. - if (isa<Constant>(IE->getOperand(2)) && isa<Constant>(EI.getOperand(1))) { - Worklist.AddValue(EI.getOperand(0)); - EI.setOperand(0, IE->getOperand(0)); - return &EI; - } - } else if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(I)) { - // If this is extracting an element from a shufflevector, figure out where - // it came from and extract from the appropriate input element instead. - if (ConstantInt *Elt = dyn_cast<ConstantInt>(EI.getOperand(1))) { - unsigned SrcIdx = getShuffleMask(SVI)[Elt->getZExtValue()]; - Value *Src; - unsigned LHSWidth = - cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements(); - - if (SrcIdx < LHSWidth) - Src = SVI->getOperand(0); - else if (SrcIdx < LHSWidth*2) { - SrcIdx -= LHSWidth; - Src = SVI->getOperand(1); - } else { - return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType())); - } - return ExtractElementInst::Create(Src, - ConstantInt::get(Type::getInt32Ty(EI.getContext()), - SrcIdx, false)); - } - } - // FIXME: Canonicalize extractelement(bitcast) -> bitcast(extractelement) - } - return 0; -} - -/// CollectSingleShuffleElements - If V is a shuffle of values that ONLY returns -/// elements from either LHS or RHS, return the shuffle mask and true. -/// Otherwise, return false. -static bool CollectSingleShuffleElements(Value *V, Value *LHS, Value *RHS, - std::vector<Constant*> &Mask) { - assert(V->getType() == LHS->getType() && V->getType() == RHS->getType() && - "Invalid CollectSingleShuffleElements"); - unsigned NumElts = cast<VectorType>(V->getType())->getNumElements(); - - if (isa<UndefValue>(V)) { - Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext()))); - return true; - } - - if (V == LHS) { - for (unsigned i = 0; i != NumElts; ++i) - Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()), i)); - return true; - } - - if (V == RHS) { - for (unsigned i = 0; i != NumElts; ++i) - Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()), - i+NumElts)); - return true; - } - - if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) { - // If this is an insert of an extract from some other vector, include it. - Value *VecOp = IEI->getOperand(0); - Value *ScalarOp = IEI->getOperand(1); - Value *IdxOp = IEI->getOperand(2); - - if (!isa<ConstantInt>(IdxOp)) - return false; - unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue(); - - if (isa<UndefValue>(ScalarOp)) { // inserting undef into vector. - // Okay, we can handle this if the vector we are insertinting into is - // transitively ok. - if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) { - // If so, update the mask to reflect the inserted undef. - Mask[InsertedIdx] = UndefValue::get(Type::getInt32Ty(V->getContext())); - return true; - } - } else if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)){ - if (isa<ConstantInt>(EI->getOperand(1)) && - EI->getOperand(0)->getType() == V->getType()) { - unsigned ExtractedIdx = - cast<ConstantInt>(EI->getOperand(1))->getZExtValue(); - - // This must be extracting from either LHS or RHS. - if (EI->getOperand(0) == LHS || EI->getOperand(0) == RHS) { - // Okay, we can handle this if the vector we are insertinting into is - // transitively ok. - if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) { - // If so, update the mask to reflect the inserted value. - if (EI->getOperand(0) == LHS) { - Mask[InsertedIdx % NumElts] = - ConstantInt::get(Type::getInt32Ty(V->getContext()), - ExtractedIdx); - } else { - assert(EI->getOperand(0) == RHS); - Mask[InsertedIdx % NumElts] = - ConstantInt::get(Type::getInt32Ty(V->getContext()), - ExtractedIdx+NumElts); - - } - return true; - } - } - } - } - } - // TODO: Handle shufflevector here! - - return false; -} - -/// CollectShuffleElements - We are building a shuffle of V, using RHS as the -/// RHS of the shuffle instruction, if it is not null. Return a shuffle mask -/// that computes V and the LHS value of the shuffle. -static Value *CollectShuffleElements(Value *V, std::vector<Constant*> &Mask, - Value *&RHS) { - assert(isa<VectorType>(V->getType()) && - (RHS == 0 || V->getType() == RHS->getType()) && - "Invalid shuffle!"); - unsigned NumElts = cast<VectorType>(V->getType())->getNumElements(); - - if (isa<UndefValue>(V)) { - Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext()))); - return V; - } else if (isa<ConstantAggregateZero>(V)) { - Mask.assign(NumElts, ConstantInt::get(Type::getInt32Ty(V->getContext()),0)); - return V; - } else if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) { - // If this is an insert of an extract from some other vector, include it. - Value *VecOp = IEI->getOperand(0); - Value *ScalarOp = IEI->getOperand(1); - Value *IdxOp = IEI->getOperand(2); - - if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) { - if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) && - EI->getOperand(0)->getType() == V->getType()) { - unsigned ExtractedIdx = - cast<ConstantInt>(EI->getOperand(1))->getZExtValue(); - unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue(); - - // Either the extracted from or inserted into vector must be RHSVec, - // otherwise we'd end up with a shuffle of three inputs. - if (EI->getOperand(0) == RHS || RHS == 0) { - RHS = EI->getOperand(0); - Value *V = CollectShuffleElements(VecOp, Mask, RHS); - Mask[InsertedIdx % NumElts] = - ConstantInt::get(Type::getInt32Ty(V->getContext()), - NumElts+ExtractedIdx); - return V; - } - - if (VecOp == RHS) { - Value *V = CollectShuffleElements(EI->getOperand(0), Mask, RHS); - // Everything but the extracted element is replaced with the RHS. - for (unsigned i = 0; i != NumElts; ++i) { - if (i != InsertedIdx) - Mask[i] = ConstantInt::get(Type::getInt32Ty(V->getContext()), - NumElts+i); - } - return V; - } - - // If this insertelement is a chain that comes from exactly these two - // vectors, return the vector and the effective shuffle. - if (CollectSingleShuffleElements(IEI, EI->getOperand(0), RHS, Mask)) - return EI->getOperand(0); - } - } - } - // TODO: Handle shufflevector here! - - // Otherwise, can't do anything fancy. Return an identity vector. - for (unsigned i = 0; i != NumElts; ++i) - Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()), i)); - return V; -} - -Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) { - Value *VecOp = IE.getOperand(0); - Value *ScalarOp = IE.getOperand(1); - Value *IdxOp = IE.getOperand(2); - - // Inserting an undef or into an undefined place, remove this. - if (isa<UndefValue>(ScalarOp) || isa<UndefValue>(IdxOp)) - ReplaceInstUsesWith(IE, VecOp); - - // If the inserted element was extracted from some other vector, and if the - // indexes are constant, try to turn this into a shufflevector operation. - if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) { - if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) && - EI->getOperand(0)->getType() == IE.getType()) { - unsigned NumVectorElts = IE.getType()->getNumElements(); - unsigned ExtractedIdx = - cast<ConstantInt>(EI->getOperand(1))->getZExtValue(); - unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue(); - - if (ExtractedIdx >= NumVectorElts) // Out of range extract. - return ReplaceInstUsesWith(IE, VecOp); - - if (InsertedIdx >= NumVectorElts) // Out of range insert. - return ReplaceInstUsesWith(IE, UndefValue::get(IE.getType())); - - // If we are extracting a value from a vector, then inserting it right - // back into the same place, just use the input vector. - if (EI->getOperand(0) == VecOp && ExtractedIdx == InsertedIdx) - return ReplaceInstUsesWith(IE, VecOp); - - // If this insertelement isn't used by some other insertelement, turn it - // (and any insertelements it points to), into one big shuffle. - if (!IE.hasOneUse() || !isa<InsertElementInst>(IE.use_back())) { - std::vector<Constant*> Mask; - Value *RHS = 0; - Value *LHS = CollectShuffleElements(&IE, Mask, RHS); - if (RHS == 0) RHS = UndefValue::get(LHS->getType()); - // We now have a shuffle of LHS, RHS, Mask. - return new ShuffleVectorInst(LHS, RHS, - ConstantVector::get(Mask)); - } - } - } - - unsigned VWidth = cast<VectorType>(VecOp->getType())->getNumElements(); - APInt UndefElts(VWidth, 0); - APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth)); - if (SimplifyDemandedVectorElts(&IE, AllOnesEltMask, UndefElts)) - return &IE; - - return 0; -} - - -Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) { - Value *LHS = SVI.getOperand(0); - Value *RHS = SVI.getOperand(1); - std::vector<unsigned> Mask = getShuffleMask(&SVI); - - bool MadeChange = false; - - // Undefined shuffle mask -> undefined value. - if (isa<UndefValue>(SVI.getOperand(2))) - return ReplaceInstUsesWith(SVI, UndefValue::get(SVI.getType())); - - unsigned VWidth = cast<VectorType>(SVI.getType())->getNumElements(); - - if (VWidth != cast<VectorType>(LHS->getType())->getNumElements()) - return 0; - - APInt UndefElts(VWidth, 0); - APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth)); - if (SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) { - LHS = SVI.getOperand(0); - RHS = SVI.getOperand(1); - MadeChange = true; - } - - // Canonicalize shuffle(x ,x,mask) -> shuffle(x, undef,mask') - // Canonicalize shuffle(undef,x,mask) -> shuffle(x, undef,mask'). - if (LHS == RHS || isa<UndefValue>(LHS)) { - if (isa<UndefValue>(LHS) && LHS == RHS) { - // shuffle(undef,undef,mask) -> undef. - return ReplaceInstUsesWith(SVI, LHS); - } - - // Remap any references to RHS to use LHS. - std::vector<Constant*> Elts; - for (unsigned i = 0, e = Mask.size(); i != e; ++i) { - if (Mask[i] >= 2*e) - Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext()))); - else { - if ((Mask[i] >= e && isa<UndefValue>(RHS)) || - (Mask[i] < e && isa<UndefValue>(LHS))) { - Mask[i] = 2*e; // Turn into undef. - Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext()))); - } else { - Mask[i] = Mask[i] % e; // Force to LHS. - Elts.push_back(ConstantInt::get(Type::getInt32Ty(SVI.getContext()), - Mask[i])); - } - } - } - SVI.setOperand(0, SVI.getOperand(1)); - SVI.setOperand(1, UndefValue::get(RHS->getType())); - SVI.setOperand(2, ConstantVector::get(Elts)); - LHS = SVI.getOperand(0); - RHS = SVI.getOperand(1); - MadeChange = true; - } - - // Analyze the shuffle, are the LHS or RHS and identity shuffles? - bool isLHSID = true, isRHSID = true; - - for (unsigned i = 0, e = Mask.size(); i != e; ++i) { - if (Mask[i] >= e*2) continue; // Ignore undef values. - // Is this an identity shuffle of the LHS value? - isLHSID &= (Mask[i] == i); - - // Is this an identity shuffle of the RHS value? - isRHSID &= (Mask[i]-e == i); - } - - // Eliminate identity shuffles. - if (isLHSID) return ReplaceInstUsesWith(SVI, LHS); - if (isRHSID) return ReplaceInstUsesWith(SVI, RHS); - - // If the LHS is a shufflevector itself, see if we can combine it with this - // one without producing an unusual shuffle. Here we are really conservative: - // we are absolutely afraid of producing a shuffle mask not in the input - // program, because the code gen may not be smart enough to turn a merged - // shuffle into two specific shuffles: it may produce worse code. As such, - // we only merge two shuffles if the result is one of the two input shuffle - // masks. In this case, merging the shuffles just removes one instruction, - // which we know is safe. This is good for things like turning: - // (splat(splat)) -> splat. - if (ShuffleVectorInst *LHSSVI = dyn_cast<ShuffleVectorInst>(LHS)) { - if (isa<UndefValue>(RHS)) { - std::vector<unsigned> LHSMask = getShuffleMask(LHSSVI); - - if (LHSMask.size() == Mask.size()) { - std::vector<unsigned> NewMask; - for (unsigned i = 0, e = Mask.size(); i != e; ++i) - if (Mask[i] >= e) - NewMask.push_back(2*e); - else - NewMask.push_back(LHSMask[Mask[i]]); - - // If the result mask is equal to the src shuffle or this - // shuffle mask, do the replacement. - if (NewMask == LHSMask || NewMask == Mask) { - unsigned LHSInNElts = - cast<VectorType>(LHSSVI->getOperand(0)->getType())-> - getNumElements(); - std::vector<Constant*> Elts; - for (unsigned i = 0, e = NewMask.size(); i != e; ++i) { - if (NewMask[i] >= LHSInNElts*2) { - Elts.push_back(UndefValue::get( - Type::getInt32Ty(SVI.getContext()))); - } else { - Elts.push_back(ConstantInt::get( - Type::getInt32Ty(SVI.getContext()), - NewMask[i])); - } - } - return new ShuffleVectorInst(LHSSVI->getOperand(0), - LHSSVI->getOperand(1), - ConstantVector::get(Elts)); - } - } - } - } - - return MadeChange ? &SVI : 0; -} - |