mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-13 20:32:21 +00:00
Extend instcombine's shufflevector simplification to handle more cases where the input and output vectors have different sizes. Patch by Xiaoyi Guo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142671 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Friedman
parent
280dfad489
commit
d2822e7572
@ -55,14 +55,14 @@ static bool CheapToScalarize(Value *V, bool isConstant) {
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/// getShuffleMask - Read and decode a shufflevector mask.
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/// Turn undef elements into negative values.
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static std::vector<int> getShuffleMask(const ShuffleVectorInst *SVI) {
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static SmallVector<int, 16> getShuffleMask(const ShuffleVectorInst *SVI) {
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unsigned NElts = SVI->getType()->getNumElements();
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if (isa<ConstantAggregateZero>(SVI->getOperand(2)))
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return std::vector<int>(NElts, 0);
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return SmallVector<int, 16>(NElts, 0);
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if (isa<UndefValue>(SVI->getOperand(2)))
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return std::vector<int>(NElts, -1);
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return SmallVector<int, 16>(NElts, -1);
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std::vector<int> Result;
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SmallVector<int, 16> Result;
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const ConstantVector *CP = cast<ConstantVector>(SVI->getOperand(2));
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for (User::const_op_iterator i = CP->op_begin(), e = CP->op_end(); i!=e; ++i)
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if (isa<UndefValue>(*i))
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@ -447,7 +447,7 @@ Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) {
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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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std::vector<int> Mask = getShuffleMask(&SVI);
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SmallVector<int, 16> Mask = getShuffleMask(&SVI);
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bool MadeChange = false;
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@ -457,9 +457,6 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
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unsigned VWidth = cast<VectorType>(SVI.getType())->getNumElements();
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if (VWidth != cast<VectorType>(LHS->getType())->getNumElements())
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return 0;
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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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@ -470,17 +467,21 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
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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').
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if (LHS == RHS || isa<UndefValue>(LHS)) {
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if (isa<UndefValue>(LHS) && LHS == RHS) {
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// shuffle(undef,undef,mask) -> undef.
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return ReplaceInstUsesWith(SVI, LHS);
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Value* result = (VWidth == LHSWidth)
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? LHS : UndefValue::get(SVI.getType());
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return ReplaceInstUsesWith(SVI, result);
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}
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// Remap any references to RHS to use LHS.
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std::vector<Constant*> Elts;
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for (unsigned i = 0, e = Mask.size(); i != e; ++i) {
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for (unsigned i = 0, e = LHSWidth; i != VWidth; ++i) {
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if (Mask[i] < 0)
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Elts.push_back(UndefValue::get(Type::getInt32Ty(SVI.getContext())));
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else {
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@ -503,6 +504,7 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
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MadeChange = true;
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}
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if (VWidth == LHSWidth) {
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// Analyze the shuffle, are the LHS or RHS and identity shuffles?
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bool isLHSID = true, isRHSID = true;
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@ -518,57 +520,189 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
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// Eliminate identity shuffles.
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if (isLHSID) return ReplaceInstUsesWith(SVI, LHS);
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if (isRHSID) return ReplaceInstUsesWith(SVI, RHS);
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}
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// If the LHS is a shufflevector itself, see if we can combine it with this
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// one without producing an unusual shuffle. Here we are really conservative:
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// one without producing an unusual shuffle.
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// Cases that might be simplified:
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// 1.
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// x1=shuffle(v1,v2,mask1)
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// x=shuffle(x1,undef,mask)
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// ==>
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// x=shuffle(v1,undef,newMask)
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// newMask[i] = (mask[i] < x1.size()) ? mask1[mask[i]] : -1
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// 2.
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// x1=shuffle(v1,undef,mask1)
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// x=shuffle(x1,x2,mask)
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// where v1.size() == mask1.size()
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// ==>
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// x=shuffle(v1,x2,newMask)
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// newMask[i] = (mask[i] < x1.size()) ? mask1[mask[i]] : mask[i]
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// 3.
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// x2=shuffle(v2,undef,mask2)
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// x=shuffle(x1,x2,mask)
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// where v2.size() == mask2.size()
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// ==>
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// x=shuffle(x1,v2,newMask)
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// newMask[i] = (mask[i] < x1.size())
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// ? mask[i] : mask2[mask[i]-x1.size()]+x1.size()
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// 4.
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// x1=shuffle(v1,undef,mask1)
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// x2=shuffle(v2,undef,mask2)
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// x=shuffle(x1,x2,mask)
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// where v1.size() == v2.size()
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// ==>
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// x=shuffle(v1,v2,newMask)
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// newMask[i] = (mask[i] < x1.size())
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// ? mask1[mask[i]] : mask2[mask[i]-x1.size()]+v1.size()
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//
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// Here we are really conservative:
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// we are absolutely afraid of producing a shuffle mask not in the input
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// program, because the code gen may not be smart enough to turn a merged
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// shuffle into two specific shuffles: it may produce worse code. As such,
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// we only merge two shuffles if the result is either a splat or one of the
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// two input shuffle masks. In this case, merging the shuffles just removes
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// input shuffle masks. In this case, merging the shuffles just removes
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// one instruction, which we know is safe. This is good for things like
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// turning: (splat(splat)) -> splat.
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if (ShuffleVectorInst *LHSSVI = dyn_cast<ShuffleVectorInst>(LHS)) {
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// turning: (splat(splat)) -> splat, or
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// merge(V[0..n], V[n+1..2n]) -> V[0..2n]
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ShuffleVectorInst* LHSShuffle = dyn_cast<ShuffleVectorInst>(LHS);
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ShuffleVectorInst* RHSShuffle = dyn_cast<ShuffleVectorInst>(RHS);
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if (LHSShuffle)
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if (!isa<UndefValue>(LHSShuffle->getOperand(1)) && !isa<UndefValue>(RHS))
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LHSShuffle = NULL;
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if (RHSShuffle)
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if (!isa<UndefValue>(RHSShuffle->getOperand(1)))
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RHSShuffle = NULL;
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if (!LHSShuffle && !RHSShuffle)
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return MadeChange ? &SVI : 0;
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Value* LHSOp0 = NULL;
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Value* LHSOp1 = NULL;
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Value* RHSOp0 = NULL;
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unsigned LHSOp0Width = 0;
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unsigned RHSOp0Width = 0;
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if (LHSShuffle) {
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LHSOp0 = LHSShuffle->getOperand(0);
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LHSOp1 = LHSShuffle->getOperand(1);
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LHSOp0Width = cast<VectorType>(LHSOp0->getType())->getNumElements();
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}
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if (RHSShuffle) {
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RHSOp0 = RHSShuffle->getOperand(0);
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RHSOp0Width = cast<VectorType>(RHSOp0->getType())->getNumElements();
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}
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Value* newLHS = LHS;
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Value* newRHS = RHS;
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if (LHSShuffle) {
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// case 1
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if (isa<UndefValue>(RHS)) {
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std::vector<int> LHSMask = getShuffleMask(LHSSVI);
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newLHS = LHSOp0;
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newRHS = LHSOp1;
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}
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// case 2 or 4
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else if (LHSOp0Width == LHSWidth) {
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newLHS = LHSOp0;
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}
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}
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// case 3 or 4
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if (RHSShuffle && RHSOp0Width == LHSWidth) {
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newRHS = RHSOp0;
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}
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// case 4
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if (LHSOp0 == RHSOp0) {
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newLHS = LHSOp0;
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newRHS = NULL;
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}
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if (LHSMask.size() == Mask.size()) {
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std::vector<int> NewMask;
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if (newLHS == LHS && newRHS == RHS)
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return MadeChange ? &SVI : 0;
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SmallVector<int, 16> LHSMask;
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SmallVector<int, 16> RHSMask;
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if (newLHS != LHS) {
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LHSMask = getShuffleMask(LHSShuffle);
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}
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if (RHSShuffle && newRHS != RHS) {
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RHSMask = getShuffleMask(RHSShuffle);
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}
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unsigned newLHSWidth = (newLHS != LHS) ? LHSOp0Width : LHSWidth;
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SmallVector<int, 16> newMask;
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bool isSplat = true;
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int SplatElt = -1; // undef
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for (unsigned i = 0, e = Mask.size(); i != e; ++i) {
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int MaskElt;
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if (Mask[i] < 0 || Mask[i] >= (int)e)
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MaskElt = -1; // undef
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else
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MaskElt = LHSMask[Mask[i]];
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// Check if this could still be a splat.
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if (MaskElt >= 0) {
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if (SplatElt >=0 && SplatElt != MaskElt)
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isSplat = false;
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SplatElt = MaskElt;
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int SplatElt = -1;
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// Create a new mask for the new ShuffleVectorInst so that the new
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// ShuffleVectorInst is equivalent to the original one.
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for (unsigned i = 0; i < VWidth; ++i) {
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int eltMask;
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if (Mask[i] == -1) {
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// This element is an undef value.
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eltMask = -1;
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} else if (Mask[i] < (int)LHSWidth) {
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// This element is from left hand side vector operand.
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//
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// If LHS is going to be replaced (case 1, 2, or 4), calculate the
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// new mask value for the element.
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if (newLHS != LHS) {
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eltMask = LHSMask[Mask[i]];
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// If the value selected is an undef value, explicitly specify it
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// with a -1 mask value.
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if (eltMask >= (int)LHSOp0Width && isa<UndefValue>(LHSOp1))
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eltMask = -1;
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}
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NewMask.push_back(MaskElt);
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else
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eltMask = Mask[i];
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} else {
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// This element is from right hand side vector operand
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//
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// If the value selected is an undef value, explicitly specify it
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// with a -1 mask value. (case 1)
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if (isa<UndefValue>(RHS))
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eltMask = -1;
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// If RHS is going to be replaced (case 3 or 4), calculate the
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// new mask value for the element.
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else if (newRHS != RHS) {
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eltMask = RHSMask[Mask[i]-LHSWidth];
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// If the value selected is an undef value, explicitly specify it
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// with a -1 mask value.
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if (eltMask >= (int)RHSOp0Width) {
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assert(isa<UndefValue>(RHSShuffle->getOperand(1))
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&& "should have been check above");
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eltMask = -1;
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}
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}
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else
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eltMask = Mask[i]-LHSWidth;
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// If LHS's width is changed, shift the mask value accordingly.
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// If newRHS == NULL, i.e. LHSOp0 == RHSOp0, we want to remap any
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// references to RHSOp0 to LHSOp0, so we don't need to shift the mask.
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if (eltMask >= 0 && newRHS != NULL)
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eltMask += newLHSWidth;
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}
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// If the result mask is equal to the src shuffle or this
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// shuffle mask, do the replacement.
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if (isSplat || NewMask == LHSMask || NewMask == Mask) {
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std::vector<Constant*> Elts;
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// Check if this could still be a splat.
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if (eltMask >= 0) {
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if (SplatElt >= 0 && SplatElt != eltMask)
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isSplat = false;
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SplatElt = eltMask;
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}
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newMask.push_back(eltMask);
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}
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// If the result mask is equal to one of the original shuffle masks,
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// or is a splat, do the replacement.
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if (isSplat || newMask == LHSMask || newMask == RHSMask || newMask == Mask) {
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SmallVector<Constant*, 16> Elts;
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Type *Int32Ty = Type::getInt32Ty(SVI.getContext());
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for (unsigned i = 0, e = NewMask.size(); i != e; ++i) {
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if (NewMask[i] < 0) {
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for (unsigned i = 0, e = newMask.size(); i != e; ++i) {
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if (newMask[i] < 0) {
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Elts.push_back(UndefValue::get(Int32Ty));
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} else {
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Elts.push_back(ConstantInt::get(Int32Ty, NewMask[i]));
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}
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}
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return new ShuffleVectorInst(LHSSVI->getOperand(0),
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LHSSVI->getOperand(1),
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ConstantVector::get(Elts));
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}
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Elts.push_back(ConstantInt::get(Int32Ty, newMask[i]));
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}
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}
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if (newRHS == NULL)
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newRHS = UndefValue::get(newLHS->getType());
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return new ShuffleVectorInst(newLHS, newRHS, ConstantVector::get(Elts));
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}
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return MadeChange ? &SVI : 0;
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@ -98,6 +98,17 @@ define <4 x i8> @test9a(<16 x i8> %tmp6) nounwind {
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ret <4 x i8> %tmp9
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}
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; Test fold of two shuffles where the first shuffle vectors inputs are a
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; different length then the second.
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define <4 x i8> @test9b(<4 x i8> %tmp6, <4 x i8> %tmp7) nounwind {
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; CHECK: @test9
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; CHECK-NEXT: shufflevector
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; CHECK-NEXT: ret
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%tmp1 = shufflevector <4 x i8> %tmp6, <4 x i8> %tmp7, <8 x i32> <i32 0, i32 1, i32 4, i32 5, i32 4, i32 5, i32 2, i32 3> ; <<4 x i8>> [#uses=1]
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%tmp9 = shufflevector <8 x i8> %tmp1, <8 x i8> undef, <4 x i32> <i32 0, i32 1, i32 4, i32 5> ; <<4 x i8>> [#uses=1]
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ret <4 x i8> %tmp9
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}
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; Redundant vector splats should be removed. Radar 8597790.
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define <4 x i32> @test10(<4 x i32> %tmp5) nounwind {
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; CHECK: @test10
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@ -107,3 +118,38 @@ define <4 x i32> @test10(<4 x i32> %tmp5) nounwind {
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%tmp7 = shufflevector <4 x i32> %tmp6, <4 x i32> undef, <4 x i32> zeroinitializer
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ret <4 x i32> %tmp7
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}
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; Test fold of two shuffles where the two shufflevector inputs's op1 are
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; the same
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define <8 x i8> @test11(<16 x i8> %tmp6) nounwind {
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; CHECK: @test11
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; CHECK-NEXT: shufflevector <16 x i8> %tmp6, <16 x i8> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
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; CHECK-NEXT: ret
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%tmp1 = shufflevector <16 x i8> %tmp6, <16 x i8> undef, <4 x i32> <i32 0, i32 1, i32 2, i32 3> ; <<4 x i8>> [#uses=1]
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%tmp2 = shufflevector <16 x i8> %tmp6, <16 x i8> undef, <4 x i32> <i32 4, i32 5, i32 6, i32 7> ; <<4 x i8>> [#uses=1]
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%tmp3 = shufflevector <4 x i8> %tmp1, <4 x i8> %tmp2, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7> ; <<8 x i8>> [#uses=1]
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ret <8 x i8> %tmp3
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}
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; Test fold of two shuffles where the first shufflevector's inputs are
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; the same as the second
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define <8 x i8> @test12(<8 x i8> %tmp6, <8 x i8> %tmp2) nounwind {
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; CHECK: @test12
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; CHECK-NEXT: shufflevector <8 x i8> %tmp6, <8 x i8> %tmp2, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 9, i32 8, i32 11, i32 12>
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; CHECK-NEXT: ret
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%tmp1 = shufflevector <8 x i8> %tmp6, <8 x i8> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 5, i32 4, i32 undef, i32 7> ; <<8 x i8>> [#uses=1]
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%tmp3 = shufflevector <8 x i8> %tmp1, <8 x i8> %tmp2, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 9, i32 8, i32 11, i32 12> ; <<8 x i8>> [#uses=1]
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ret <8 x i8> %tmp3
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}
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; Test fold of two shuffles where the first shufflevector's inputs are
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; the same as the second
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define <8 x i8> @test12a(<8 x i8> %tmp6, <8 x i8> %tmp2) nounwind {
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; CHECK: @test12a
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; CHECK-NEXT: shufflevector <8 x i8> %tmp2, <8 x i8> %tmp6, <8 x i32> <i32 0, i32 3, i32 1, i32 4, i32 8, i32 9, i32 10, i32 11>
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; CHECK-NEXT: ret
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%tmp1 = shufflevector <8 x i8> %tmp6, <8 x i8> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 5, i32 4, i32 undef, i32 7> ; <<8 x i8>> [#uses=1]
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%tmp3 = shufflevector <8 x i8> %tmp2, <8 x i8> %tmp1, <8 x i32> <i32 0, i32 3, i32 1, i32 4, i32 8, i32 9, i32 10, i32 11> ; <<8 x i8>> [#uses=1]
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ret <8 x i8> %tmp3
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}
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