C++ VectorType::getNumElements方法代码示例

  /// Return a random value with a known type.
  Value *getRandomValue(Type *Tp) {
    unsigned index = Ran->Rand();
    for (unsigned i=0; i<PT->size(); ++i) {
      Value *V = PT->at((index + i) % PT->size());
      if (V->getType() == Tp)
        return V;
    }

    // If the requested type was not found, generate a constant value.
    if (Tp->isIntegerTy()) {
      if (Ran->Rand() & 1)
        return ConstantInt::getAllOnesValue(Tp);
      return ConstantInt::getNullValue(Tp);
    } else if (Tp->isFloatingPointTy()) {
      if (Ran->Rand() & 1)
        return ConstantFP::getAllOnesValue(Tp);
      return ConstantFP::getNullValue(Tp);
    } else if (Tp->isVectorTy()) {
      VectorType *VTp = cast<VectorType>(Tp);

      std::vector<Constant*> TempValues;
      TempValues.reserve(VTp->getNumElements());
      for (unsigned i = 0; i < VTp->getNumElements(); ++i)
        TempValues.push_back(getRandomConstant(VTp->getScalarType()));

      ArrayRef<Constant*> VectorValue(TempValues);
      return ConstantVector::get(VectorValue);
    }

    return UndefValue::get(Tp);
  }

bool Scalarizer::visitBitCastInst(BitCastInst &BCI) {
  VectorType *DstVT = dyn_cast<VectorType>(BCI.getDestTy());
  VectorType *SrcVT = dyn_cast<VectorType>(BCI.getSrcTy());
  if (!DstVT || !SrcVT)
    return false;

  unsigned DstNumElems = DstVT->getNumElements();
  unsigned SrcNumElems = SrcVT->getNumElements();
  IRBuilder<> Builder(BCI.getParent(), &BCI);
  Scatterer Op0 = scatter(&BCI, BCI.getOperand(0));
  ValueVector Res;
  Res.resize(DstNumElems);

  if (DstNumElems == SrcNumElems) {
    for (unsigned I = 0; I < DstNumElems; ++I)
      Res[I] = Builder.CreateBitCast(Op0[I], DstVT->getElementType(),
                                     BCI.getName() + ".i" + Twine(I));
  } else if (DstNumElems > SrcNumElems) {
    // <M x t1> -> <N*M x t2>.  Convert each t1 to <N x t2> and copy the
    // individual elements to the destination.
    unsigned FanOut = DstNumElems / SrcNumElems;
    Type *MidTy = VectorType::get(DstVT->getElementType(), FanOut);
    unsigned ResI = 0;
    for (unsigned Op0I = 0; Op0I < SrcNumElems; ++Op0I) {
      Value *V = Op0[Op0I];
      Instruction *VI;
      // Look through any existing bitcasts before converting to <N x t2>.
      // In the best case, the resulting conversion might be a no-op.
      while ((VI = dyn_cast<Instruction>(V)) &&
             VI->getOpcode() == Instruction::BitCast)
        V = VI->getOperand(0);
      V = Builder.CreateBitCast(V, MidTy, V->getName() + ".cast");
      Scatterer Mid = scatter(&BCI, V);
      for (unsigned MidI = 0; MidI < FanOut; ++MidI)
        Res[ResI++] = Mid[MidI];
    }
  } else {
    // <N*M x t1> -> <M x t2>.  Convert each group of <N x t1> into a t2.
    unsigned FanIn = SrcNumElems / DstNumElems;
    Type *MidTy = VectorType::get(SrcVT->getElementType(), FanIn);
    unsigned Op0I = 0;
    for (unsigned ResI = 0; ResI < DstNumElems; ++ResI) {
      Value *V = UndefValue::get(MidTy);
      for (unsigned MidI = 0; MidI < FanIn; ++MidI)
        V = Builder.CreateInsertElement(V, Op0[Op0I++], Builder.getInt32(MidI),
                                        BCI.getName() + ".i" + Twine(ResI)
                                        + ".upto" + Twine(MidI));
      Res[ResI] = Builder.CreateBitCast(V, DstVT->getElementType(),
                                        BCI.getName() + ".i" + Twine(ResI));
    }
  }
  gather(&BCI, Res);
  return true;
}

static bool isZero(Value *V, const DataLayout &DL, DominatorTree *DT,
                   AssumptionCache *AC) {
  // Assume undef could be zero.
  if (isa<UndefValue>(V))
    return true;

  VectorType *VecTy = dyn_cast<VectorType>(V->getType());
  if (!VecTy) {
    KnownBits Known = computeKnownBits(V, DL, 0, AC, dyn_cast<Instruction>(V), DT);
    return Known.isZero();
  }

  // Per-component check doesn't work with zeroinitializer
  Constant *C = dyn_cast<Constant>(V);
  if (!C)
    return false;

  if (C->isZeroValue())
    return true;

  // For a vector, KnownZero will only be true if all values are zero, so check
  // this per component
  for (unsigned I = 0, N = VecTy->getNumElements(); I != N; ++I) {
    Constant *Elem = C->getAggregateElement(I);
    if (isa<UndefValue>(Elem))
      return true;

    KnownBits Known = computeKnownBits(Elem, DL);
    if (Known.isZero())
      return true;
  }

  return false;
}

bool Scalarizer::visitGetElementPtrInst(GetElementPtrInst &GEPI) {
  VectorType *VT = dyn_cast<VectorType>(GEPI.getType());
  if (!VT)
    return false;

  IRBuilder<> Builder(&GEPI);
  unsigned NumElems = VT->getNumElements();
  unsigned NumIndices = GEPI.getNumIndices();

  Scatterer Base = scatter(&GEPI, GEPI.getOperand(0));

  SmallVector<Scatterer, 8> Ops;
  Ops.resize(NumIndices);
  for (unsigned I = 0; I < NumIndices; ++I)
    Ops[I] = scatter(&GEPI, GEPI.getOperand(I + 1));

  ValueVector Res;
  Res.resize(NumElems);
  for (unsigned I = 0; I < NumElems; ++I) {
    SmallVector<Value *, 8> Indices;
    Indices.resize(NumIndices);
    for (unsigned J = 0; J < NumIndices; ++J)
      Indices[J] = Ops[J][I];
    Res[I] = Builder.CreateGEP(GEPI.getSourceElementType(), Base[I], Indices,
                               GEPI.getName() + ".i" + Twine(I));
    if (GEPI.isInBounds())
      if (GetElementPtrInst *NewGEPI = dyn_cast<GetElementPtrInst>(Res[I]))
        NewGEPI->setIsInBounds();
  }
  gather(&GEPI, Res);
  return true;
}

bool Scalarizer::visitSelectInst(SelectInst &SI) {
  VectorType *VT = dyn_cast<VectorType>(SI.getType());
  if (!VT)
    return false;

  unsigned NumElems = VT->getNumElements();
  IRBuilder<> Builder(SI.getParent(), &SI);
  Scatterer Op1 = scatter(&SI, SI.getOperand(1));
  Scatterer Op2 = scatter(&SI, SI.getOperand(2));
  assert(Op1.size() == NumElems && "Mismatched select");
  assert(Op2.size() == NumElems && "Mismatched select");
  ValueVector Res;
  Res.resize(NumElems);

  if (SI.getOperand(0)->getType()->isVectorTy()) {
    Scatterer Op0 = scatter(&SI, SI.getOperand(0));
    assert(Op0.size() == NumElems && "Mismatched select");
    for (unsigned I = 0; I < NumElems; ++I)
      Res[I] = Builder.CreateSelect(Op0[I], Op1[I], Op2[I],
                                    SI.getName() + ".i" + Twine(I));
  } else {
    Value *Op0 = SI.getOperand(0);
    for (unsigned I = 0; I < NumElems; ++I)
      Res[I] = Builder.CreateSelect(Op0, Op1[I], Op2[I],
                                    SI.getName() + ".i" + Twine(I));
  }
  gather(&SI, Res);
  return true;
}

/// getEVT - Return the value type corresponding to the specified type.  This
/// returns all pointers as MVT::iPTR.  If HandleUnknown is true, unknown types
/// are returned as Other, otherwise they are invalid.
EVT EVT::getEVT(Type *Ty, bool HandleUnknown){
  switch (Ty->getTypeID()) {
  default:
    return MVT::getVT(Ty, HandleUnknown);
  case Type::IntegerTyID:
    return getIntegerVT(Ty->getContext(), cast<IntegerType>(Ty)->getBitWidth());
  case Type::VectorTyID: {
    VectorType *VTy = cast<VectorType>(Ty);
    return getVectorVT(Ty->getContext(), getEVT(VTy->getElementType(), false),
                       VTy->getNumElements());
  }
  }
}

/// \brief 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.
llvm::Value *llvm::findScalarElement(llvm::Value *V, unsigned EltNo) {
  assert(V->getType()->isVectorTy() && "Not looking at a vector?");
  VectorType *VTy = cast<VectorType>(V->getType());
  unsigned Width = VTy->getNumElements();
  if (EltNo >= Width)  // Out of range access.
    return UndefValue::get(VTy->getElementType());

  if (Constant *C = dyn_cast<Constant>(V))
    return C->getAggregateElement(EltNo);

  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 nullptr;
    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);
  }

  if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V)) {
    unsigned LHSWidth = SVI->getOperand(0)->getType()->getVectorNumElements();
    int InEl = SVI->getMaskValue(EltNo);
    if (InEl < 0)
      return UndefValue::get(VTy->getElementType());
    if (InEl < (int)LHSWidth)
      return findScalarElement(SVI->getOperand(0), InEl);
    return findScalarElement(SVI->getOperand(1), InEl - LHSWidth);
  }

  // Extract a value from a vector add operation with a constant zero.
  Value *Val = nullptr; Constant *Con = nullptr;
  if (match(V,
            llvm::PatternMatch::m_Add(llvm::PatternMatch::m_Value(Val),
                                      llvm::PatternMatch::m_Constant(Con)))) {
    if (Con->getAggregateElement(EltNo)->isNullValue())
      return findScalarElement(Val, EltNo);
  }

  // Otherwise, we don't know.
  return nullptr;
}

bool Scalarizer::visitCastInst(CastInst &CI) {
  VectorType *VT = dyn_cast<VectorType>(CI.getDestTy());
  if (!VT)
    return false;

  unsigned NumElems = VT->getNumElements();
  IRBuilder<> Builder(CI.getParent(), &CI);
  Scatterer Op0 = scatter(&CI, CI.getOperand(0));
  assert(Op0.size() == NumElems && "Mismatched cast");
  ValueVector Res;
  Res.resize(NumElems);
  for (unsigned I = 0; I < NumElems; ++I)
    Res[I] = Builder.CreateCast(CI.getOpcode(), Op0[I], VT->getElementType(),
                                CI.getName() + ".i" + Twine(I));
  gather(&CI, Res);
  return true;
}

/// 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(V->getType()->isVectorTy() && "Not looking at a vector?");
  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());
  if (isa<ConstantAggregateZero>(V))
    return Constant::getNullValue(PTy->getElementType());
  if (ConstantVector *CP = dyn_cast<ConstantVector>(V))
    return CP->getOperand(EltNo);

  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);
  }

  if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(V)) {
    unsigned LHSWidth =
      cast<VectorType>(SVI->getOperand(0)->getType())->getNumElements();
    int InEl = SVI->getMaskValue(EltNo);
    if (InEl < 0)
      return UndefValue::get(PTy->getElementType());
    if (InEl < (int)LHSWidth)
      return FindScalarElement(SVI->getOperand(0), InEl);
    return FindScalarElement(SVI->getOperand(1), InEl - LHSWidth);
  }

  // Otherwise, we don't know.
  return 0;
}

bool Scalarizer::splitBinary(Instruction &I, const Splitter &Split) {
  VectorType *VT = dyn_cast<VectorType>(I.getType());
  if (!VT)
    return false;

  unsigned NumElems = VT->getNumElements();
  IRBuilder<> Builder(I.getParent(), &I);
  Scatterer Op0 = scatter(&I, I.getOperand(0));
  Scatterer Op1 = scatter(&I, I.getOperand(1));
  assert(Op0.size() == NumElems && "Mismatched binary operation");
  assert(Op1.size() == NumElems && "Mismatched binary operation");
  ValueVector Res;
  Res.resize(NumElems);
  for (unsigned Elem = 0; Elem < NumElems; ++Elem)
    Res[Elem] = Split(Builder, Op0[Elem], Op1[Elem],
                      I.getName() + ".i" + Twine(Elem));
  gather(&I, Res);
  return true;
}

unsigned GCNTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index,
                                       Type *SubTp) {
  if (ST->hasVOP3PInsts()) {
    VectorType *VT = cast<VectorType>(Tp);
    if (VT->getNumElements() == 2 &&
        DL.getTypeSizeInBits(VT->getElementType()) == 16) {
      // With op_sel VOP3P instructions freely can access the low half or high
      // half of a register, so any swizzle is free.

      switch (Kind) {
      case TTI::SK_Broadcast:
      case TTI::SK_Reverse:
      case TTI::SK_PermuteSingleSrc:
        return 0;
      default:
        break;
      }
    }
  }

  return BaseT::getShuffleCost(Kind, Tp, Index, SubTp);
}

bool Scalarizer::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
  VectorType *VT = dyn_cast<VectorType>(SVI.getType());
  if (!VT)
    return false;

  unsigned NumElems = VT->getNumElements();
  Scatterer Op0 = scatter(&SVI, SVI.getOperand(0));
  Scatterer Op1 = scatter(&SVI, SVI.getOperand(1));
  ValueVector Res;
  Res.resize(NumElems);

  for (unsigned I = 0; I < NumElems; ++I) {
    int Selector = SVI.getMaskValue(I);
    if (Selector < 0)
      Res[I] = UndefValue::get(VT->getElementType());
    else if (unsigned(Selector) < Op0.size())
      Res[I] = Op0[Selector];
    else
      Res[I] = Op1[Selector - Op0.size()];
  }
  gather(&SVI, Res);
  return true;
}

static bool isZero(Value *V, const DataLayout *DL) {
    // Assume undef could be zero.
    if (isa<UndefValue>(V))
        return true;

    VectorType *VecTy = dyn_cast<VectorType>(V->getType());
    if (!VecTy) {
        unsigned BitWidth = V->getType()->getIntegerBitWidth();
        APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
        computeKnownBits(V, KnownZero, KnownOne, DL);
        return KnownZero.isAllOnesValue();
    }

    // Per-component check doesn't work with zeroinitializer
    Constant *C = dyn_cast<Constant>(V);
    if (!C)
        return false;

    if (C->isZeroValue())
        return true;

    // For a vector, KnownZero will only be true if all values are zero, so check
    // this per component
    unsigned BitWidth = VecTy->getElementType()->getIntegerBitWidth();
    for (unsigned I = 0, N = VecTy->getNumElements(); I != N; ++I) {
        Constant *Elem = C->getAggregateElement(I);
        if (isa<UndefValue>(Elem))
            return true;

        APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
        computeKnownBits(Elem, KnownZero, KnownOne, DL);
        if (KnownZero.isAllOnesValue())
            return true;
    }

    return false;
}

/// Return the value type corresponding to the specified type.  This returns all
/// pointers as MVT::iPTR.  If HandleUnknown is true, unknown types are returned
/// as Other, otherwise they are invalid.
MVT MVT::getVT(Type *Ty, bool HandleUnknown){
  switch (Ty->getTypeID()) {
  default:
    if (HandleUnknown) return MVT(MVT::Other);
    llvm_unreachable("Unknown type!");
  case Type::VoidTyID:
    return MVT::isVoid;
  case Type::IntegerTyID:
    return getIntegerVT(cast<IntegerType>(Ty)->getBitWidth());
  case Type::HalfTyID:      return MVT(MVT::f16);
  case Type::FloatTyID:     return MVT(MVT::f32);
  case Type::DoubleTyID:    return MVT(MVT::f64);
  case Type::X86_FP80TyID:  return MVT(MVT::f80);
  case Type::X86_MMXTyID:   return MVT(MVT::x86mmx);
  case Type::FP128TyID:     return MVT(MVT::f128);
  case Type::PPC_FP128TyID: return MVT(MVT::ppcf128);
  case Type::PointerTyID:   return MVT(MVT::iPTR);
  case Type::VectorTyID: {
    VectorType *VTy = cast<VectorType>(Ty);
    return getVectorVT(
      getVT(VTy->getElementType(), false), VTy->getNumElements());
  }
  }
}

bool Scalarizer::visitPHINode(PHINode &PHI) {
  VectorType *VT = dyn_cast<VectorType>(PHI.getType());
  if (!VT)
    return false;

  unsigned NumElems = VT->getNumElements();
  IRBuilder<> Builder(PHI.getParent(), &PHI);
  ValueVector Res;
  Res.resize(NumElems);

  unsigned NumOps = PHI.getNumOperands();
  for (unsigned I = 0; I < NumElems; ++I)
    Res[I] = Builder.CreatePHI(VT->getElementType(), NumOps,
                               PHI.getName() + ".i" + Twine(I));

  for (unsigned I = 0; I < NumOps; ++I) {
    Scatterer Op = scatter(&PHI, PHI.getIncomingValue(I));
    BasicBlock *IncomingBlock = PHI.getIncomingBlock(I);
    for (unsigned J = 0; J < NumElems; ++J)
      cast<PHINode>(Res[J])->addIncoming(Op[J], IncomingBlock);
  }
  gather(&PHI, Res);
  return true;
}