673 lines
26 KiB
C++
673 lines
26 KiB
C++
//===- InstCombineVectorOps.cpp -------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements instcombine for ExtractElement, InsertElement and
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// ShuffleVector.
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//
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//===----------------------------------------------------------------------===//
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#include "InstCombine.h"
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using namespace llvm;
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/// CheapToScalarize - Return true if the value is cheaper to scalarize than it
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/// is to leave as a vector operation. isConstant indicates whether we're
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/// extracting one known element. If false we're extracting a variable index.
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static bool CheapToScalarize(Value *V, bool isConstant) {
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if (Constant *C = dyn_cast<Constant>(V)) {
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if (isConstant) return true;
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// If all elts are the same, we can extract it and use any of the values.
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Constant *Op0 = C->getAggregateElement(0U);
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for (unsigned i = 1, e = V->getType()->getVectorNumElements(); i != e; ++i)
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if (C->getAggregateElement(i) != Op0)
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return false;
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return true;
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}
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Instruction *I = dyn_cast<Instruction>(V);
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if (!I) return false;
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// Insert element gets simplified to the inserted element or is deleted if
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// this is constant idx extract element and its a constant idx insertelt.
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if (I->getOpcode() == Instruction::InsertElement && isConstant &&
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isa<ConstantInt>(I->getOperand(2)))
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return true;
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if (I->getOpcode() == Instruction::Load && I->hasOneUse())
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return true;
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if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I))
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if (BO->hasOneUse() &&
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(CheapToScalarize(BO->getOperand(0), isConstant) ||
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CheapToScalarize(BO->getOperand(1), isConstant)))
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return true;
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if (CmpInst *CI = dyn_cast<CmpInst>(I))
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if (CI->hasOneUse() &&
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(CheapToScalarize(CI->getOperand(0), isConstant) ||
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CheapToScalarize(CI->getOperand(1), isConstant)))
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return true;
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return false;
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}
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/// FindScalarElement - Given a vector and an element number, see if the scalar
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/// value is already around as a register, for example if it were inserted then
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/// extracted from the vector.
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static Value *FindScalarElement(Value *V, unsigned EltNo) {
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assert(V->getType()->isVectorTy() && "Not looking at a vector?");
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VectorType *VTy = cast<VectorType>(V->getType());
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unsigned Width = VTy->getNumElements();
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if (EltNo >= Width) // Out of range access.
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return UndefValue::get(VTy->getElementType());
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if (Constant *C = dyn_cast<Constant>(V))
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return C->getAggregateElement(EltNo);
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if (InsertElementInst *III = dyn_cast<InsertElementInst>(V)) {
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// If this is an insert to a variable element, we don't know what it is.
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if (!isa<ConstantInt>(III->getOperand(2)))
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return 0;
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unsigned IIElt = cast<ConstantInt>(III->getOperand(2))->getZExtValue();
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// If this is an insert to the element we are looking for, return the
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// inserted value.
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if (EltNo == IIElt)
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return III->getOperand(1);
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// Otherwise, the insertelement doesn't modify the value, recurse on its
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// vector input.
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return FindScalarElement(III->getOperand(0), EltNo);
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}
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if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V)) {
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unsigned LHSWidth = SVI->getOperand(0)->getType()->getVectorNumElements();
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int InEl = SVI->getMaskValue(EltNo);
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if (InEl < 0)
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return UndefValue::get(VTy->getElementType());
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if (InEl < (int)LHSWidth)
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return FindScalarElement(SVI->getOperand(0), InEl);
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return FindScalarElement(SVI->getOperand(1), InEl - LHSWidth);
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}
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// Otherwise, we don't know.
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return 0;
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}
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Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
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// If vector val is constant with all elements the same, replace EI with
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// that element. We handle a known element # below.
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if (Constant *C = dyn_cast<Constant>(EI.getOperand(0)))
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if (CheapToScalarize(C, false))
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return ReplaceInstUsesWith(EI, C->getAggregateElement(0U));
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// If extracting a specified index from the vector, see if we can recursively
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// find a previously computed scalar that was inserted into the vector.
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if (ConstantInt *IdxC = dyn_cast<ConstantInt>(EI.getOperand(1))) {
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unsigned IndexVal = IdxC->getZExtValue();
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unsigned VectorWidth = EI.getVectorOperandType()->getNumElements();
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// If this is extracting an invalid index, turn this into undef, to avoid
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// crashing the code below.
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if (IndexVal >= VectorWidth)
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return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
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// This instruction only demands the single element from the input vector.
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// If the input vector has a single use, simplify it based on this use
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// property.
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if (EI.getOperand(0)->hasOneUse() && VectorWidth != 1) {
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APInt UndefElts(VectorWidth, 0);
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APInt DemandedMask(VectorWidth, 0);
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DemandedMask.setBit(IndexVal);
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if (Value *V = SimplifyDemandedVectorElts(EI.getOperand(0),
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DemandedMask, UndefElts)) {
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EI.setOperand(0, V);
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return &EI;
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}
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}
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if (Value *Elt = FindScalarElement(EI.getOperand(0), IndexVal))
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return ReplaceInstUsesWith(EI, Elt);
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// If the this extractelement is directly using a bitcast from a vector of
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// the same number of elements, see if we can find the source element from
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// it. In this case, we will end up needing to bitcast the scalars.
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if (BitCastInst *BCI = dyn_cast<BitCastInst>(EI.getOperand(0))) {
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if (VectorType *VT = dyn_cast<VectorType>(BCI->getOperand(0)->getType()))
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if (VT->getNumElements() == VectorWidth)
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if (Value *Elt = FindScalarElement(BCI->getOperand(0), IndexVal))
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return new BitCastInst(Elt, EI.getType());
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}
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}
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if (Instruction *I = dyn_cast<Instruction>(EI.getOperand(0))) {
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// Push extractelement into predecessor operation if legal and
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// profitable to do so
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if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
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if (I->hasOneUse() &&
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CheapToScalarize(BO, isa<ConstantInt>(EI.getOperand(1)))) {
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Value *newEI0 =
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Builder->CreateExtractElement(BO->getOperand(0), EI.getOperand(1),
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EI.getName()+".lhs");
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Value *newEI1 =
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Builder->CreateExtractElement(BO->getOperand(1), EI.getOperand(1),
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EI.getName()+".rhs");
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return BinaryOperator::Create(BO->getOpcode(), newEI0, newEI1);
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}
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} else if (InsertElementInst *IE = dyn_cast<InsertElementInst>(I)) {
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// Extracting the inserted element?
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if (IE->getOperand(2) == EI.getOperand(1))
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return ReplaceInstUsesWith(EI, IE->getOperand(1));
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// If the inserted and extracted elements are constants, they must not
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// be the same value, extract from the pre-inserted value instead.
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if (isa<Constant>(IE->getOperand(2)) && isa<Constant>(EI.getOperand(1))) {
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Worklist.AddValue(EI.getOperand(0));
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EI.setOperand(0, IE->getOperand(0));
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return &EI;
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}
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} else if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(I)) {
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// If this is extracting an element from a shufflevector, figure out where
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// it came from and extract from the appropriate input element instead.
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if (ConstantInt *Elt = dyn_cast<ConstantInt>(EI.getOperand(1))) {
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int SrcIdx = SVI->getMaskValue(Elt->getZExtValue());
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Value *Src;
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unsigned LHSWidth =
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SVI->getOperand(0)->getType()->getVectorNumElements();
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if (SrcIdx < 0)
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return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
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if (SrcIdx < (int)LHSWidth)
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Src = SVI->getOperand(0);
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else {
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SrcIdx -= LHSWidth;
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Src = SVI->getOperand(1);
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}
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Type *Int32Ty = Type::getInt32Ty(EI.getContext());
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return ExtractElementInst::Create(Src,
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ConstantInt::get(Int32Ty,
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SrcIdx, false));
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}
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} else if (CastInst *CI = dyn_cast<CastInst>(I)) {
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// Canonicalize extractelement(cast) -> cast(extractelement)
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// bitcasts can change the number of vector elements and they cost nothing
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if (CI->hasOneUse() && EI.hasOneUse() &&
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(CI->getOpcode() != Instruction::BitCast)) {
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Value *EE = Builder->CreateExtractElement(CI->getOperand(0),
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EI.getIndexOperand());
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return CastInst::Create(CI->getOpcode(), EE, EI.getType());
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}
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}
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}
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return 0;
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}
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/// CollectSingleShuffleElements - If V is a shuffle of values that ONLY returns
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/// elements from either LHS or RHS, return the shuffle mask and true.
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/// Otherwise, return false.
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static bool CollectSingleShuffleElements(Value *V, Value *LHS, Value *RHS,
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SmallVectorImpl<Constant*> &Mask) {
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assert(V->getType() == LHS->getType() && V->getType() == RHS->getType() &&
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"Invalid CollectSingleShuffleElements");
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unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
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if (isa<UndefValue>(V)) {
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Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext())));
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return true;
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}
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if (V == LHS) {
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for (unsigned i = 0; i != NumElts; ++i)
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Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()), i));
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return true;
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}
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if (V == RHS) {
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for (unsigned i = 0; i != NumElts; ++i)
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Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()),
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i+NumElts));
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return true;
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}
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if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) {
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// If this is an insert of an extract from some other vector, include it.
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Value *VecOp = IEI->getOperand(0);
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Value *ScalarOp = IEI->getOperand(1);
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Value *IdxOp = IEI->getOperand(2);
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if (!isa<ConstantInt>(IdxOp))
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return false;
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unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
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if (isa<UndefValue>(ScalarOp)) { // inserting undef into vector.
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// Okay, we can handle this if the vector we are insertinting into is
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// transitively ok.
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if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
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// If so, update the mask to reflect the inserted undef.
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Mask[InsertedIdx] = UndefValue::get(Type::getInt32Ty(V->getContext()));
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return true;
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}
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} else if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)){
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if (isa<ConstantInt>(EI->getOperand(1)) &&
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EI->getOperand(0)->getType() == V->getType()) {
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unsigned ExtractedIdx =
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cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
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// This must be extracting from either LHS or RHS.
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if (EI->getOperand(0) == LHS || EI->getOperand(0) == RHS) {
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// Okay, we can handle this if the vector we are insertinting into is
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// transitively ok.
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if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
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// If so, update the mask to reflect the inserted value.
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if (EI->getOperand(0) == LHS) {
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Mask[InsertedIdx % NumElts] =
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ConstantInt::get(Type::getInt32Ty(V->getContext()),
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ExtractedIdx);
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} else {
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assert(EI->getOperand(0) == RHS);
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Mask[InsertedIdx % NumElts] =
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ConstantInt::get(Type::getInt32Ty(V->getContext()),
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ExtractedIdx+NumElts);
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}
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return true;
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}
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}
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}
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}
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}
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// TODO: Handle shufflevector here!
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return false;
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}
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/// CollectShuffleElements - We are building a shuffle of V, using RHS as the
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/// RHS of the shuffle instruction, if it is not null. Return a shuffle mask
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/// that computes V and the LHS value of the shuffle.
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static Value *CollectShuffleElements(Value *V, SmallVectorImpl<Constant*> &Mask,
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Value *&RHS) {
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assert(V->getType()->isVectorTy() &&
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(RHS == 0 || V->getType() == RHS->getType()) &&
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"Invalid shuffle!");
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unsigned NumElts = cast<VectorType>(V->getType())->getNumElements();
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if (isa<UndefValue>(V)) {
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Mask.assign(NumElts, UndefValue::get(Type::getInt32Ty(V->getContext())));
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return V;
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}
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if (isa<ConstantAggregateZero>(V)) {
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Mask.assign(NumElts, ConstantInt::get(Type::getInt32Ty(V->getContext()),0));
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return V;
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}
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if (InsertElementInst *IEI = dyn_cast<InsertElementInst>(V)) {
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// If this is an insert of an extract from some other vector, include it.
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Value *VecOp = IEI->getOperand(0);
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Value *ScalarOp = IEI->getOperand(1);
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Value *IdxOp = IEI->getOperand(2);
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if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
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if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
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EI->getOperand(0)->getType() == V->getType()) {
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unsigned ExtractedIdx =
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cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
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unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
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// Either the extracted from or inserted into vector must be RHSVec,
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// otherwise we'd end up with a shuffle of three inputs.
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if (EI->getOperand(0) == RHS || RHS == 0) {
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RHS = EI->getOperand(0);
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Value *V = CollectShuffleElements(VecOp, Mask, RHS);
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Mask[InsertedIdx % NumElts] =
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ConstantInt::get(Type::getInt32Ty(V->getContext()),
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NumElts+ExtractedIdx);
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return V;
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}
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if (VecOp == RHS) {
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Value *V = CollectShuffleElements(EI->getOperand(0), Mask, RHS);
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// Everything but the extracted element is replaced with the RHS.
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for (unsigned i = 0; i != NumElts; ++i) {
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if (i != InsertedIdx)
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Mask[i] = ConstantInt::get(Type::getInt32Ty(V->getContext()),
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NumElts+i);
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}
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return V;
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}
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// If this insertelement is a chain that comes from exactly these two
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// vectors, return the vector and the effective shuffle.
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if (CollectSingleShuffleElements(IEI, EI->getOperand(0), RHS, Mask))
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return EI->getOperand(0);
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}
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}
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}
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// TODO: Handle shufflevector here!
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// Otherwise, can't do anything fancy. Return an identity vector.
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for (unsigned i = 0; i != NumElts; ++i)
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Mask.push_back(ConstantInt::get(Type::getInt32Ty(V->getContext()), i));
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return V;
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}
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Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) {
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Value *VecOp = IE.getOperand(0);
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Value *ScalarOp = IE.getOperand(1);
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Value *IdxOp = IE.getOperand(2);
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// Inserting an undef or into an undefined place, remove this.
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if (isa<UndefValue>(ScalarOp) || isa<UndefValue>(IdxOp))
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ReplaceInstUsesWith(IE, VecOp);
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// If the inserted element was extracted from some other vector, and if the
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// indexes are constant, try to turn this into a shufflevector operation.
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if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
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if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
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EI->getOperand(0)->getType() == IE.getType()) {
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unsigned NumVectorElts = IE.getType()->getNumElements();
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unsigned ExtractedIdx =
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cast<ConstantInt>(EI->getOperand(1))->getZExtValue();
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unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getZExtValue();
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if (ExtractedIdx >= NumVectorElts) // Out of range extract.
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return ReplaceInstUsesWith(IE, VecOp);
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if (InsertedIdx >= NumVectorElts) // Out of range insert.
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return ReplaceInstUsesWith(IE, UndefValue::get(IE.getType()));
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// If we are extracting a value from a vector, then inserting it right
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// back into the same place, just use the input vector.
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if (EI->getOperand(0) == VecOp && ExtractedIdx == InsertedIdx)
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return ReplaceInstUsesWith(IE, VecOp);
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// If this insertelement isn't used by some other insertelement, turn it
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// (and any insertelements it points to), into one big shuffle.
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if (!IE.hasOneUse() || !isa<InsertElementInst>(IE.use_back())) {
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SmallVector<Constant*, 16> Mask;
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Value *RHS = 0;
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Value *LHS = CollectShuffleElements(&IE, Mask, RHS);
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if (RHS == 0) RHS = UndefValue::get(LHS->getType());
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// We now have a shuffle of LHS, RHS, Mask.
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return new ShuffleVectorInst(LHS, RHS, ConstantVector::get(Mask));
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}
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}
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}
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unsigned VWidth = cast<VectorType>(VecOp->getType())->getNumElements();
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APInt UndefElts(VWidth, 0);
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APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
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if (Value *V = SimplifyDemandedVectorElts(&IE, AllOnesEltMask, UndefElts)) {
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if (V != &IE)
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return ReplaceInstUsesWith(IE, V);
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return &IE;
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}
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return 0;
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}
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Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
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Value *LHS = SVI.getOperand(0);
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Value *RHS = SVI.getOperand(1);
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SmallVector<int, 16> Mask = SVI.getShuffleMask();
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bool MadeChange = false;
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// Undefined shuffle mask -> undefined value.
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if (isa<UndefValue>(SVI.getOperand(2)))
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return ReplaceInstUsesWith(SVI, UndefValue::get(SVI.getType()));
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unsigned VWidth = cast<VectorType>(SVI.getType())->getNumElements();
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APInt UndefElts(VWidth, 0);
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APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
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if (Value *V = SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
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if (V != &SVI)
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return ReplaceInstUsesWith(SVI, V);
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LHS = SVI.getOperand(0);
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RHS = SVI.getOperand(1);
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MadeChange = true;
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}
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unsigned LHSWidth = cast<VectorType>(LHS->getType())->getNumElements();
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// Canonicalize shuffle(x ,x,mask) -> shuffle(x, undef,mask')
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// 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.
|
|
Value* result = (VWidth == LHSWidth)
|
|
? LHS : UndefValue::get(SVI.getType());
|
|
return ReplaceInstUsesWith(SVI, result);
|
|
}
|
|
|
|
// Remap any references to RHS to use LHS.
|
|
SmallVector<Constant*, 16> Elts;
|
|
for (unsigned i = 0, e = LHSWidth; i != VWidth; ++i) {
|
|
if (Mask[i] < 0) {
|
|
Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext())));
|
|
continue;
|
|
}
|
|
|
|
if ((Mask[i] >= (int)e && isa<UndefValue>(RHS)) ||
|
|
(Mask[i] < (int)e && isa<UndefValue>(LHS))) {
|
|
Mask[i] = -1; // 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;
|
|
}
|
|
|
|
if (VWidth == LHSWidth) {
|
|
// 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] < 0) continue; // Ignore undef values.
|
|
// Is this an identity shuffle of the LHS value?
|
|
isLHSID &= (Mask[i] == (int)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.
|
|
// Cases that might be simplified:
|
|
// 1.
|
|
// x1=shuffle(v1,v2,mask1)
|
|
// x=shuffle(x1,undef,mask)
|
|
// ==>
|
|
// x=shuffle(v1,undef,newMask)
|
|
// newMask[i] = (mask[i] < x1.size()) ? mask1[mask[i]] : -1
|
|
// 2.
|
|
// x1=shuffle(v1,undef,mask1)
|
|
// x=shuffle(x1,x2,mask)
|
|
// where v1.size() == mask1.size()
|
|
// ==>
|
|
// x=shuffle(v1,x2,newMask)
|
|
// newMask[i] = (mask[i] < x1.size()) ? mask1[mask[i]] : mask[i]
|
|
// 3.
|
|
// x2=shuffle(v2,undef,mask2)
|
|
// x=shuffle(x1,x2,mask)
|
|
// where v2.size() == mask2.size()
|
|
// ==>
|
|
// x=shuffle(x1,v2,newMask)
|
|
// newMask[i] = (mask[i] < x1.size())
|
|
// ? mask[i] : mask2[mask[i]-x1.size()]+x1.size()
|
|
// 4.
|
|
// x1=shuffle(v1,undef,mask1)
|
|
// x2=shuffle(v2,undef,mask2)
|
|
// x=shuffle(x1,x2,mask)
|
|
// where v1.size() == v2.size()
|
|
// ==>
|
|
// x=shuffle(v1,v2,newMask)
|
|
// newMask[i] = (mask[i] < x1.size())
|
|
// ? mask1[mask[i]] : mask2[mask[i]-x1.size()]+v1.size()
|
|
//
|
|
// 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 either a splat or one of the
|
|
// 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, or
|
|
// merge(V[0..n], V[n+1..2n]) -> V[0..2n]
|
|
ShuffleVectorInst* LHSShuffle = dyn_cast<ShuffleVectorInst>(LHS);
|
|
ShuffleVectorInst* RHSShuffle = dyn_cast<ShuffleVectorInst>(RHS);
|
|
if (LHSShuffle)
|
|
if (!isa<UndefValue>(LHSShuffle->getOperand(1)) && !isa<UndefValue>(RHS))
|
|
LHSShuffle = NULL;
|
|
if (RHSShuffle)
|
|
if (!isa<UndefValue>(RHSShuffle->getOperand(1)))
|
|
RHSShuffle = NULL;
|
|
if (!LHSShuffle && !RHSShuffle)
|
|
return MadeChange ? &SVI : 0;
|
|
|
|
Value* LHSOp0 = NULL;
|
|
Value* LHSOp1 = NULL;
|
|
Value* RHSOp0 = NULL;
|
|
unsigned LHSOp0Width = 0;
|
|
unsigned RHSOp0Width = 0;
|
|
if (LHSShuffle) {
|
|
LHSOp0 = LHSShuffle->getOperand(0);
|
|
LHSOp1 = LHSShuffle->getOperand(1);
|
|
LHSOp0Width = cast<VectorType>(LHSOp0->getType())->getNumElements();
|
|
}
|
|
if (RHSShuffle) {
|
|
RHSOp0 = RHSShuffle->getOperand(0);
|
|
RHSOp0Width = cast<VectorType>(RHSOp0->getType())->getNumElements();
|
|
}
|
|
Value* newLHS = LHS;
|
|
Value* newRHS = RHS;
|
|
if (LHSShuffle) {
|
|
// case 1
|
|
if (isa<UndefValue>(RHS)) {
|
|
newLHS = LHSOp0;
|
|
newRHS = LHSOp1;
|
|
}
|
|
// case 2 or 4
|
|
else if (LHSOp0Width == LHSWidth) {
|
|
newLHS = LHSOp0;
|
|
}
|
|
}
|
|
// case 3 or 4
|
|
if (RHSShuffle && RHSOp0Width == LHSWidth) {
|
|
newRHS = RHSOp0;
|
|
}
|
|
// case 4
|
|
if (LHSOp0 == RHSOp0) {
|
|
newLHS = LHSOp0;
|
|
newRHS = NULL;
|
|
}
|
|
|
|
if (newLHS == LHS && newRHS == RHS)
|
|
return MadeChange ? &SVI : 0;
|
|
|
|
SmallVector<int, 16> LHSMask;
|
|
SmallVector<int, 16> RHSMask;
|
|
if (newLHS != LHS)
|
|
LHSMask = LHSShuffle->getShuffleMask();
|
|
if (RHSShuffle && newRHS != RHS)
|
|
RHSMask = RHSShuffle->getShuffleMask();
|
|
|
|
unsigned newLHSWidth = (newLHS != LHS) ? LHSOp0Width : LHSWidth;
|
|
SmallVector<int, 16> newMask;
|
|
bool isSplat = true;
|
|
int SplatElt = -1;
|
|
// Create a new mask for the new ShuffleVectorInst so that the new
|
|
// ShuffleVectorInst is equivalent to the original one.
|
|
for (unsigned i = 0; i < VWidth; ++i) {
|
|
int eltMask;
|
|
if (Mask[i] == -1) {
|
|
// This element is an undef value.
|
|
eltMask = -1;
|
|
} else if (Mask[i] < (int)LHSWidth) {
|
|
// This element is from left hand side vector operand.
|
|
//
|
|
// If LHS is going to be replaced (case 1, 2, or 4), calculate the
|
|
// new mask value for the element.
|
|
if (newLHS != LHS) {
|
|
eltMask = LHSMask[Mask[i]];
|
|
// If the value selected is an undef value, explicitly specify it
|
|
// with a -1 mask value.
|
|
if (eltMask >= (int)LHSOp0Width && isa<UndefValue>(LHSOp1))
|
|
eltMask = -1;
|
|
}
|
|
else
|
|
eltMask = Mask[i];
|
|
} else {
|
|
// This element is from right hand side vector operand
|
|
//
|
|
// If the value selected is an undef value, explicitly specify it
|
|
// with a -1 mask value. (case 1)
|
|
if (isa<UndefValue>(RHS))
|
|
eltMask = -1;
|
|
// If RHS is going to be replaced (case 3 or 4), calculate the
|
|
// new mask value for the element.
|
|
else if (newRHS != RHS) {
|
|
eltMask = RHSMask[Mask[i]-LHSWidth];
|
|
// If the value selected is an undef value, explicitly specify it
|
|
// with a -1 mask value.
|
|
if (eltMask >= (int)RHSOp0Width) {
|
|
assert(isa<UndefValue>(RHSShuffle->getOperand(1))
|
|
&& "should have been check above");
|
|
eltMask = -1;
|
|
}
|
|
}
|
|
else
|
|
eltMask = Mask[i]-LHSWidth;
|
|
|
|
// If LHS's width is changed, shift the mask value accordingly.
|
|
// If newRHS == NULL, i.e. LHSOp0 == RHSOp0, we want to remap any
|
|
// references to RHSOp0 to LHSOp0, so we don't need to shift the mask.
|
|
if (eltMask >= 0 && newRHS != NULL)
|
|
eltMask += newLHSWidth;
|
|
}
|
|
|
|
// Check if this could still be a splat.
|
|
if (eltMask >= 0) {
|
|
if (SplatElt >= 0 && SplatElt != eltMask)
|
|
isSplat = false;
|
|
SplatElt = eltMask;
|
|
}
|
|
|
|
newMask.push_back(eltMask);
|
|
}
|
|
|
|
// If the result mask is equal to one of the original shuffle masks,
|
|
// or is a splat, do the replacement.
|
|
if (isSplat || newMask == LHSMask || newMask == RHSMask || newMask == Mask) {
|
|
SmallVector<Constant*, 16> Elts;
|
|
Type *Int32Ty = Type::getInt32Ty(SVI.getContext());
|
|
for (unsigned i = 0, e = newMask.size(); i != e; ++i) {
|
|
if (newMask[i] < 0) {
|
|
Elts.push_back(UndefValue::get(Int32Ty));
|
|
} else {
|
|
Elts.push_back(ConstantInt::get(Int32Ty, newMask[i]));
|
|
}
|
|
}
|
|
if (newRHS == NULL)
|
|
newRHS = UndefValue::get(newLHS->getType());
|
|
return new ShuffleVectorInst(newLHS, newRHS, ConstantVector::get(Elts));
|
|
}
|
|
|
|
return MadeChange ? &SVI : 0;
|
|
}
|