C++ LLT::getElementType方法代码示例

static LegalizeMutation oneMoreElement(unsigned TypeIdx) {
  return [=](const LegalityQuery &Query) {
    const LLT Ty = Query.Types[TypeIdx];
    const LLT EltTy = Ty.getElementType();
    return std::make_pair(TypeIdx, LLT::vector(Ty.getNumElements() + 1, EltTy));
  };
}

static LegalityPredicate isSmallOddVector(unsigned TypeIdx) {
  return [=](const LegalityQuery &Query) {
    const LLT Ty = Query.Types[TypeIdx];
    return Ty.isVector() &&
           Ty.getNumElements() % 2 != 0 &&
           Ty.getElementType().getSizeInBits() < 32;
  };
}

// Make sure the returned mutation makes sense for the match type.
static bool mutationIsSane(const LegalizeRule &Rule,
                           const LegalityQuery &Q,
                           std::pair<unsigned, LLT> Mutation) {
  const unsigned TypeIdx = Mutation.first;
  const LLT OldTy = Q.Types[TypeIdx];
  const LLT NewTy = Mutation.second;

  switch (Rule.getAction()) {
  case FewerElements:
  case MoreElements: {
    if (!OldTy.isVector())
      return false;

    if (NewTy.isVector()) {
      if (Rule.getAction() == FewerElements) {
        // Make sure the element count really decreased.
        if (NewTy.getNumElements() >= OldTy.getNumElements())
          return false;
      } else {
        // Make sure the element count really increased.
        if (NewTy.getNumElements() <= OldTy.getNumElements())
          return false;
      }
    }

    // Make sure the element type didn't change.
    return NewTy.getScalarType() == OldTy.getElementType();
  }
  case NarrowScalar:
  case WidenScalar: {
    if (OldTy.isVector()) {
      // Number of elements should not change.
      if (!NewTy.isVector() || OldTy.getNumElements() != NewTy.getNumElements())
        return false;
    } else {
      // Both types must be vectors
      if (NewTy.isVector())
        return false;
    }

    if (Rule.getAction() == NarrowScalar)  {
      // Make sure the size really decreased.
      if (NewTy.getScalarSizeInBits() >= OldTy.getScalarSizeInBits())
        return false;
    } else {
      // Make sure the size really increased.
      if (NewTy.getScalarSizeInBits() <= OldTy.getScalarSizeInBits())
        return false;
    }

    return true;
  }
  default:
    return true;
  }
}

static LegalizeMutation fewerEltsToSize64Vector(unsigned TypeIdx) {
  return [=](const LegalityQuery &Query) {
    const LLT Ty = Query.Types[TypeIdx];
    const LLT EltTy = Ty.getElementType();
    unsigned Size = Ty.getSizeInBits();
    unsigned Pieces = (Size + 63) / 64;
    unsigned NewNumElts = (Ty.getNumElements() + 1) / Pieces;
    return std::make_pair(TypeIdx, LLT::scalarOrVector(NewNumElts, EltTy));
  };
}

LegalizeMutation LegalizeMutations::moreElementsToNextPow2(unsigned TypeIdx,
                                                           unsigned Min) {
  return [=](const LegalityQuery &Query) {
    const LLT VecTy = Query.Types[TypeIdx];
    unsigned NewNumElements =
        std::max(1u << Log2_32_Ceil(VecTy.getNumElements()), Min);
    return std::make_pair(TypeIdx,
                          LLT::vector(NewNumElements, VecTy.getElementType()));
  };
}

void MachineLegalizer::computeTables() {
  for (auto &Op : Actions) {
    LLT Ty = Op.first.second;
    if (!Ty.isVector())
      continue;

    auto &Entry =
        MaxLegalVectorElts[std::make_pair(Op.first.first, Ty.getElementType())];
    Entry = std::max(Entry, Ty.getNumElements());
  }

  TablesInitialized = true;
}

// FIXME: inefficient implementation for now. Without ComputeValueVTs we're
// probably going to need specialized lookup structures for various types before
// we have any hope of doing well with something like <13 x i3>. Even the common
// cases should do better than what we have now.
std::pair<MachineLegalizer::LegalizeAction, LLT>
MachineLegalizer::getAction(const InstrAspect &Aspect) const {
  assert(TablesInitialized && "backend forgot to call computeTables");
  // These *have* to be implemented for now, they're the fundamental basis of
  // how everything else is transformed.

  // FIXME: the long-term plan calls for expansion in terms of load/store (if
  // they're not legal).
  if (Aspect.Opcode == TargetOpcode::G_SEQUENCE ||
      Aspect.Opcode == TargetOpcode::G_EXTRACT)
    return std::make_pair(Legal, Aspect.Type);

  LegalizeAction Action = findInActions(Aspect);
  if (Action != NotFound)
    return findLegalAction(Aspect, Action);

  unsigned Opcode = Aspect.Opcode;
  LLT Ty = Aspect.Type;
  if (!Ty.isVector()) {
    auto DefaultAction = DefaultActions.find(Aspect.Opcode);
    if (DefaultAction != DefaultActions.end() && DefaultAction->second == Legal)
      return std::make_pair(Legal, Ty);

    assert(DefaultAction->second == NarrowScalar && "unexpected default");
    return findLegalAction(Aspect, NarrowScalar);
  }

  LLT EltTy = Ty.getElementType();
  int NumElts = Ty.getNumElements();

  auto ScalarAction = ScalarInVectorActions.find(std::make_pair(Opcode, EltTy));
  if (ScalarAction != ScalarInVectorActions.end() &&
      ScalarAction->second != Legal)
    return findLegalAction(Aspect, ScalarAction->second);

  // The element type is legal in principle, but the number of elements is
  // wrong.
  auto MaxLegalElts = MaxLegalVectorElts.lookup(std::make_pair(Opcode, EltTy));
  if (MaxLegalElts > NumElts)
    return findLegalAction(Aspect, MoreElements);

  if (MaxLegalElts == 0) {
    // Scalarize if there's no legal vector type, which is just a special case
    // of FewerElements.
    return std::make_pair(FewerElements, EltTy);
  }

  return findLegalAction(Aspect, FewerElements);
}

void LegalizerInfo::computeTables() {
  for (unsigned Opcode = 0; Opcode <= LastOp - FirstOp; ++Opcode) {
    for (unsigned Idx = 0; Idx != Actions[Opcode].size(); ++Idx) {
      for (auto &Action : Actions[Opcode][Idx]) {
        LLT Ty = Action.first;
        if (!Ty.isVector())
          continue;

        auto &Entry = MaxLegalVectorElts[std::make_pair(Opcode + FirstOp,
                                                        Ty.getElementType())];
        Entry = std::max(Entry, Ty.getNumElements());
      }
    }
  }

  TablesInitialized = true;
}

// FIXME: inefficient implementation for now. Without ComputeValueVTs we're
// probably going to need specialized lookup structures for various types before
// we have any hope of doing well with something like <13 x i3>. Even the common
// cases should do better than what we have now.
std::pair<LegalizerInfo::LegalizeAction, LLT>
LegalizerInfo::getAction(const InstrAspect &Aspect) const {
  assert(TablesInitialized && "backend forgot to call computeTables");
  // These *have* to be implemented for now, they're the fundamental basis of
  // how everything else is transformed.

  // FIXME: the long-term plan calls for expansion in terms of load/store (if
  // they're not legal).
  if (Aspect.Opcode == TargetOpcode::G_MERGE_VALUES ||
      Aspect.Opcode == TargetOpcode::G_UNMERGE_VALUES)
    return std::make_pair(Legal, Aspect.Type);

  LLT Ty = Aspect.Type;
  LegalizeAction Action = findInActions(Aspect);
  // LegalizerHelper is not able to handle non-power-of-2 types right now, so do
  // not try to legalize them unless they are marked as Legal or Custom.
  // FIXME: This is a temporary hack until the general non-power-of-2
  // legalization works.
  if (!isPowerOf2_64(Ty.getSizeInBits()) &&
      !(Action == Legal || Action == Custom))
    return std::make_pair(Unsupported, LLT());

  if (Action != NotFound)
    return findLegalAction(Aspect, Action);

  unsigned Opcode = Aspect.Opcode;
  if (!Ty.isVector()) {
    auto DefaultAction = DefaultActions.find(Aspect.Opcode);
    if (DefaultAction != DefaultActions.end() && DefaultAction->second == Legal)
      return std::make_pair(Legal, Ty);

    if (DefaultAction != DefaultActions.end() && DefaultAction->second == Lower)
      return std::make_pair(Lower, Ty);

    if (DefaultAction == DefaultActions.end() ||
        DefaultAction->second != NarrowScalar)
      return std::make_pair(Unsupported, LLT());
    return findLegalAction(Aspect, NarrowScalar);
  }

  LLT EltTy = Ty.getElementType();
  int NumElts = Ty.getNumElements();

  auto ScalarAction = ScalarInVectorActions.find(std::make_pair(Opcode, EltTy));
  if (ScalarAction != ScalarInVectorActions.end() &&
      ScalarAction->second != Legal)
    return findLegalAction(Aspect, ScalarAction->second);

  // The element type is legal in principle, but the number of elements is
  // wrong.
  auto MaxLegalElts = MaxLegalVectorElts.lookup(std::make_pair(Opcode, EltTy));
  if (MaxLegalElts > NumElts)
    return findLegalAction(Aspect, MoreElements);

  if (MaxLegalElts == 0) {
    // Scalarize if there's no legal vector type, which is just a special case
    // of FewerElements.
    return std::make_pair(FewerElements, EltTy);
  }

  return findLegalAction(Aspect, FewerElements);
}

void LegalizerInfo::computeTables() {
  assert(TablesInitialized == false);

  for (unsigned OpcodeIdx = 0; OpcodeIdx <= LastOp - FirstOp; ++OpcodeIdx) {
    const unsigned Opcode = FirstOp + OpcodeIdx;
    for (unsigned TypeIdx = 0; TypeIdx != SpecifiedActions[OpcodeIdx].size();
         ++TypeIdx) {
      // 0. Collect information specified through the setAction API, i.e.
      // for specific bit sizes.
      // For scalar types:
      SizeAndActionsVec ScalarSpecifiedActions;
      // For pointer types:
      std::map<uint16_t, SizeAndActionsVec> AddressSpace2SpecifiedActions;
      // For vector types:
      std::map<uint16_t, SizeAndActionsVec> ElemSize2SpecifiedActions;
      for (auto LLT2Action : SpecifiedActions[OpcodeIdx][TypeIdx]) {
        const LLT Type = LLT2Action.first;
        const LegalizeAction Action = LLT2Action.second;

        auto SizeAction = std::make_pair(Type.getSizeInBits(), Action);
        if (Type.isPointer())
          AddressSpace2SpecifiedActions[Type.getAddressSpace()].push_back(
              SizeAction);
        else if (Type.isVector())
          ElemSize2SpecifiedActions[Type.getElementType().getSizeInBits()]
              .push_back(SizeAction);
        else
          ScalarSpecifiedActions.push_back(SizeAction);
      }

      // 1. Handle scalar types
      {
        // Decide how to handle bit sizes for which no explicit specification
        // was given.
        SizeChangeStrategy S = &unsupportedForDifferentSizes;
        if (TypeIdx < ScalarSizeChangeStrategies[OpcodeIdx].size() &&
            ScalarSizeChangeStrategies[OpcodeIdx][TypeIdx] != nullptr)
          S = ScalarSizeChangeStrategies[OpcodeIdx][TypeIdx];
        std::sort(ScalarSpecifiedActions.begin(), ScalarSpecifiedActions.end());
        checkPartialSizeAndActionsVector(ScalarSpecifiedActions);
        setScalarAction(Opcode, TypeIdx, S(ScalarSpecifiedActions));
      }

      // 2. Handle pointer types
      for (auto PointerSpecifiedActions : AddressSpace2SpecifiedActions) {
        std::sort(PointerSpecifiedActions.second.begin(),
                  PointerSpecifiedActions.second.end());
        checkPartialSizeAndActionsVector(PointerSpecifiedActions.second);
        // For pointer types, we assume that there isn't a meaningfull way
        // to change the number of bits used in the pointer.
        setPointerAction(
            Opcode, TypeIdx, PointerSpecifiedActions.first,
            unsupportedForDifferentSizes(PointerSpecifiedActions.second));
      }

      // 3. Handle vector types
      SizeAndActionsVec ElementSizesSeen;
      for (auto VectorSpecifiedActions : ElemSize2SpecifiedActions) {
        std::sort(VectorSpecifiedActions.second.begin(),
                  VectorSpecifiedActions.second.end());
        const uint16_t ElementSize = VectorSpecifiedActions.first;
        ElementSizesSeen.push_back({ElementSize, Legal});
        checkPartialSizeAndActionsVector(VectorSpecifiedActions.second);
        // For vector types, we assume that the best way to adapt the number
        // of elements is to the next larger number of elements type for which
        // the vector type is legal, unless there is no such type. In that case,
        // legalize towards a vector type with a smaller number of elements.
        SizeAndActionsVec NumElementsActions;
        for (SizeAndAction BitsizeAndAction : VectorSpecifiedActions.second) {
          assert(BitsizeAndAction.first % ElementSize == 0);
          const uint16_t NumElements = BitsizeAndAction.first / ElementSize;
          NumElementsActions.push_back({NumElements, BitsizeAndAction.second});
        }
        setVectorNumElementAction(
            Opcode, TypeIdx, ElementSize,
            moreToWiderTypesAndLessToWidest(NumElementsActions));
      }
      std::sort(ElementSizesSeen.begin(), ElementSizesSeen.end());
      SizeChangeStrategy VectorElementSizeChangeStrategy =
          &unsupportedForDifferentSizes;
      if (TypeIdx < VectorElementSizeChangeStrategies[OpcodeIdx].size() &&
          VectorElementSizeChangeStrategies[OpcodeIdx][TypeIdx] != nullptr)
        VectorElementSizeChangeStrategy =
            VectorElementSizeChangeStrategies[OpcodeIdx][TypeIdx];
      setScalarInVectorAction(
          Opcode, TypeIdx, VectorElementSizeChangeStrategy(ElementSizesSeen));
    }
  }

  TablesInitialized = true;
}