text: //===- CodeGenDAGPatterns.cpp - Read DAG patterns from .td file -----------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file implements the CodeGenDAGPatterns class, which is used to read and
  // represent the patterns present in a .td file for instructions.
  //
  //===----------------------------------------------------------------------===//
  
  #include "CodeGenDAGPatterns.h"
  #include "llvm/TableGen/Error.h"
  #include "llvm/TableGen/Record.h"
  #include "llvm/ADT/StringExtras.h"
  #include "llvm/ADT/STLExtras.h"
  #include "llvm/ADT/Twine.h"
  #include "llvm/Support/Debug.h"
  #include "llvm/Support/ErrorHandling.h"
  #include <algorithm>
  #include <cstdio>
  #include <set>
  using namespace llvm;
  
  //===----------------------------------------------------------------------===//
  //  EEVT::TypeSet Implementation
  //===----------------------------------------------------------------------===//
  
  static inline bool isInteger(MVT::SimpleValueType VT) {
    return EVT(VT).isInteger();
  }
  static inline bool isFloatingPoint(MVT::SimpleValueType VT) {
    return EVT(VT).isFloatingPoint();
  }
  static inline bool isVector(MVT::SimpleValueType VT) {
    return EVT(VT).isVector();
  }
  static inline bool isScalar(MVT::SimpleValueType VT) {
    return !EVT(VT).isVector();
  }
  
  EEVT::TypeSet::TypeSet(MVT::SimpleValueType VT, TreePattern &TP) {
    if (VT == MVT::iAny)
      EnforceInteger(TP);
    else if (VT == MVT::fAny)
      EnforceFloatingPoint(TP);
    else if (VT == MVT::vAny)
      EnforceVector(TP);
    else {
      assert((VT < MVT::LAST_VALUETYPE || VT == MVT::iPTR ||
              VT == MVT::iPTRAny) && "Not a concrete type!");
      TypeVec.push_back(VT);
    }
  }
  
  
  EEVT::TypeSet::TypeSet(const std::vector<MVT::SimpleValueType> &VTList) {
    assert(!VTList.empty() && "empty list?");
    TypeVec.append(VTList.begin(), VTList.end());
  
    if (!VTList.empty())
      assert(VTList[0] != MVT::iAny && VTList[0] != MVT::vAny &&
             VTList[0] != MVT::fAny);
  
    // Verify no duplicates.
    array_pod_sort(TypeVec.begin(), TypeVec.end());
    assert(std::unique(TypeVec.begin(), TypeVec.end()) == TypeVec.end());
  }
  
  /// FillWithPossibleTypes - Set to all legal types and return true, only valid
  /// on completely unknown type sets.
  bool EEVT::TypeSet::FillWithPossibleTypes(TreePattern &TP,
                                            bool (*Pred)(MVT::SimpleValueType),
                                            const char *PredicateName) {
    assert(isCompletelyUnknown());
    const std::vector<MVT::SimpleValueType> &LegalTypes =
      TP.getDAGPatterns().getTargetInfo().getLegalValueTypes();
  
    for (unsigned i = 0, e = LegalTypes.size(); i != e; ++i)
      if (Pred == 0 || Pred(LegalTypes[i]))
        TypeVec.push_back(LegalTypes[i]);
  
    // If we have nothing that matches the predicate, bail out.
    if (TypeVec.empty())
      TP.error("Type inference contradiction found, no " +
               std::string(PredicateName) + " types found");
    // No need to sort with one element.
    if (TypeVec.size() == 1) return true;
  
    // Remove duplicates.
    array_pod_sort(TypeVec.begin(), TypeVec.end());
    TypeVec.erase(std::unique(TypeVec.begin(), TypeVec.end()), TypeVec.end());
  
    return true;
  }
  
  /// hasIntegerTypes - Return true if this TypeSet contains iAny or an
  /// integer value type.
  bool EEVT::TypeSet::hasIntegerTypes() const {
    for (unsigned i = 0, e = TypeVec.size(); i != e; ++i)
      if (isInteger(TypeVec[i]))
        return true;
    return false;
  }
  
  /// hasFloatingPointTypes - Return true if this TypeSet contains an fAny or
  /// a floating point value type.
  bool EEVT::TypeSet::hasFloatingPointTypes() const {
    for (unsigned i = 0, e = TypeVec.size(); i != e; ++i)
      if (isFloatingPoint(TypeVec[i]))
        return true;
    return false;
  }
  
  /// hasVectorTypes - Return true if this TypeSet contains a vAny or a vector
  /// value type.
  bool EEVT::TypeSet::hasVectorTypes() const {
    for (unsigned i = 0, e = TypeVec.size(); i != e; ++i)
      if (isVector(TypeVec[i]))
        return true;
    return false;
  }
  
  
  std::string EEVT::TypeSet::getName() const {
    if (TypeVec.empty()) return "<empty>";
  
    std::string Result;
  
    for (unsigned i = 0, e = TypeVec.size(); i != e; ++i) {
      std::string VTName = llvm::getEnumName(TypeVec[i]);
      // Strip off MVT:: prefix if present.
      if (VTName.substr(0,5) == "MVT::")
        VTName = VTName.substr(5);
      if (i) Result += ':';
      Result += VTName;
    }
  
    if (TypeVec.size() == 1)
      return Result;
    return "{" + Result + "}";
  }
  
  /// MergeInTypeInfo - This merges in type information from the specified
  /// argument.  If 'this' changes, it returns true.  If the two types are
  /// contradictory (e.g. merge f32 into i32) then this throws an exception.
  bool EEVT::TypeSet::MergeInTypeInfo(const EEVT::TypeSet &InVT, TreePattern &TP){
    if (InVT.isCompletelyUnknown() || *this == InVT)
      return false;
  
    if (isCompletelyUnknown()) {
      *this = InVT;
      return true;
    }
  
    assert(TypeVec.size() >= 1 && InVT.TypeVec.size() >= 1 && "No unknowns");
  
    // Handle the abstract cases, seeing if we can resolve them better.
    switch (TypeVec[0]) {
    default: break;
    case MVT::iPTR:
    case MVT::iPTRAny:
      if (InVT.hasIntegerTypes()) {
        EEVT::TypeSet InCopy(InVT);
        InCopy.EnforceInteger(TP);
        InCopy.EnforceScalar(TP);
  
        if (InCopy.isConcrete()) {
          // If the RHS has one integer type, upgrade iPTR to i32.
          TypeVec[0] = InVT.TypeVec[0];
          return true;
        }
  
        // If the input has multiple scalar integers, this doesn't add any info.
        if (!InCopy.isCompletelyUnknown())
          return false;
      }
      break;
    }
  
    // If the input constraint is iAny/iPTR and this is an integer type list,
    // remove non-integer types from the list.
    if ((InVT.TypeVec[0] == MVT::iPTR || InVT.TypeVec[0] == MVT::iPTRAny) &&
        hasIntegerTypes()) {
      bool MadeChange = EnforceInteger(TP);
  
      // If we're merging in iPTR/iPTRAny and the node currently has a list of
      // multiple different integer types, replace them with a single iPTR.
      if ((InVT.TypeVec[0] == MVT::iPTR || InVT.TypeVec[0] == MVT::iPTRAny) &&
          TypeVec.size() != 1) {
        TypeVec.resize(1);
        TypeVec[0] = InVT.TypeVec[0];
        MadeChange = true;
      }
  
      return MadeChange;
    }
  
    // If this is a type list and the RHS is a typelist as well, eliminate entries
    // from this list that aren't in the other one.
    bool MadeChange = false;
    TypeSet InputSet(*this);
  
    for (unsigned i = 0; i != TypeVec.size(); ++i) {
      bool InInVT = false;
      for (unsigned j = 0, e = InVT.TypeVec.size(); j != e; ++j)
        if (TypeVec[i] == InVT.TypeVec[j]) {
          InInVT = true;
          break;
        }
  
      if (InInVT) continue;
      TypeVec.erase(TypeVec.begin()+i--);
      MadeChange = true;
    }
  
    // If we removed all of our types, we have a type contradiction.
    if (!TypeVec.empty())
      return MadeChange;
  
    // FIXME: Really want an SMLoc here!
    TP.error("Type inference contradiction found, merging '" +
             InVT.getName() + "' into '" + InputSet.getName() + "'");
    return true; // unreachable
  }
  
  /// EnforceInteger - Remove all non-integer types from this set.
  bool EEVT::TypeSet::EnforceInteger(TreePattern &TP) {
    // If we know nothing, then get the full set.
    if (TypeVec.empty())
      return FillWithPossibleTypes(TP, isInteger, "integer");
    if (!hasFloatingPointTypes())
      return false;
  
    TypeSet InputSet(*this);
  
    // Filter out all the fp types.
    for (unsigned i = 0; i != TypeVec.size(); ++i)
      if (!isInteger(TypeVec[i]))
        TypeVec.erase(TypeVec.begin()+i--);
  
    if (TypeVec.empty())
      TP.error("Type inference contradiction found, '" +
               InputSet.getName() + "' needs to be integer");
    return true;
  }
  
  /// EnforceFloatingPoint - Remove all integer types from this set.
  bool EEVT::TypeSet::EnforceFloatingPoint(TreePattern &TP) {
    // If we know nothing, then get the full set.
    if (TypeVec.empty())
      return FillWithPossibleTypes(TP, isFloatingPoint, "floating point");
  
    if (!hasIntegerTypes())
      return false;
  
    TypeSet InputSet(*this);
  
    // Filter out all the fp types.
    for (unsigned i = 0; i != TypeVec.size(); ++i)
      if (!isFloatingPoint(TypeVec[i]))
        TypeVec.erase(TypeVec.begin()+i--);
  
    if (TypeVec.empty())
      TP.error("Type inference contradiction found, '" +
               InputSet.getName() + "' needs to be floating point");
    return true;
  }
  
  /// EnforceScalar - Remove all vector types from this.
  bool EEVT::TypeSet::EnforceScalar(TreePattern &TP) {
    // If we know nothing, then get the full set.
    if (TypeVec.empty())
      return FillWithPossibleTypes(TP, isScalar, "scalar");
  
    if (!hasVectorTypes())
      return false;
  
    TypeSet InputSet(*this);
  
    // Filter out all the vector types.
    for (unsigned i = 0; i != TypeVec.size(); ++i)
      if (!isScalar(TypeVec[i]))
        TypeVec.erase(TypeVec.begin()+i--);
  
    if (TypeVec.empty())
      TP.error("Type inference contradiction found, '" +
               InputSet.getName() + "' needs to be scalar");
    return true;
  }
  
  /// EnforceVector - Remove all vector types from this.
  bool EEVT::TypeSet::EnforceVector(TreePattern &TP) {
    // If we know nothing, then get the full set.
    if (TypeVec.empty())
      return FillWithPossibleTypes(TP, isVector, "vector");
  
    TypeSet InputSet(*this);
    bool MadeChange = false;
  
    // Filter out all the scalar types.
    for (unsigned i = 0; i != TypeVec.size(); ++i)
      if (!isVector(TypeVec[i])) {
        TypeVec.erase(TypeVec.begin()+i--);
        MadeChange = true;
      }
  
    if (TypeVec.empty())
      TP.error("Type inference contradiction found, '" +
               InputSet.getName() + "' needs to be a vector");
    return MadeChange;
  }
  
  
  
  /// EnforceSmallerThan - 'this' must be a smaller VT than Other.  Update
  /// this an other based on this information.
  bool EEVT::TypeSet::EnforceSmallerThan(EEVT::TypeSet &Other, TreePattern &TP) {
    // Both operands must be integer or FP, but we don't care which.
    bool MadeChange = false;
  
    if (isCompletelyUnknown())
      MadeChange = FillWithPossibleTypes(TP);
  
    if (Other.isCompletelyUnknown())
      MadeChange = Other.FillWithPossibleTypes(TP);
  
    // If one side is known to be integer or known to be FP but the other side has
    // no information, get at least the type integrality info in there.
    if (!hasFloatingPointTypes())
      MadeChange |= Other.EnforceInteger(TP);
    else if (!hasIntegerTypes())
      MadeChange |= Other.EnforceFloatingPoint(TP);
    if (!Other.hasFloatingPointTypes())
      MadeChange |= EnforceInteger(TP);
    else if (!Other.hasIntegerTypes())
      MadeChange |= EnforceFloatingPoint(TP);
  
    assert(!isCompletelyUnknown() && !Other.isCompletelyUnknown() &&
           "Should have a type list now");
  
    // If one contains vectors but the other doesn't pull vectors out.
    if (!hasVectorTypes())
      MadeChange |= Other.EnforceScalar(TP);
    if (!hasVectorTypes())
      MadeChange |= EnforceScalar(TP);
  
    if (TypeVec.size() == 1 && Other.TypeVec.size() == 1) {
      // If we are down to concrete types, this code does not currently
      // handle nodes which have multiple types, where some types are
      // integer, and some are fp.  Assert that this is not the case.
      assert(!(hasIntegerTypes() && hasFloatingPointTypes()) &&
             !(Other.hasIntegerTypes() && Other.hasFloatingPointTypes()) &&
             "SDTCisOpSmallerThanOp does not handle mixed int/fp types!");
  
      // Otherwise, if these are both vector types, either this vector
      // must have a larger bitsize than the other, or this element type
      // must be larger than the other.
      EVT Type(TypeVec[0]);
      EVT OtherType(Other.TypeVec[0]);
  
      if (hasVectorTypes() && Other.hasVectorTypes()) {
        if (Type.getSizeInBits() >= OtherType.getSizeInBits())
          if (Type.getVectorElementType().getSizeInBits()
              >= OtherType.getVectorElementType().getSizeInBits())
            TP.error("Type inference contradiction found, '" +
                     getName() + "' element type not smaller than '" +
                     Other.getName() +"'!");
      }
      else
        // For scalar types, the bitsize of this type must be larger
        // than that of the other.
        if (Type.getSizeInBits() >= OtherType.getSizeInBits())
          TP.error("Type inference contradiction found, '" +
                   getName() + "' is not smaller than '" +
                   Other.getName() +"'!");
  
    }
    
  
    // Handle int and fp as disjoint sets.  This won't work for patterns
    // that have mixed fp/int types but those are likely rare and would
    // not have been accepted by this code previously.
  
    // Okay, find the smallest type from the current set and remove it from the
    // largest set.
    MVT::SimpleValueType SmallestInt = MVT::LAST_VALUETYPE;
    for (unsigned i = 0, e = TypeVec.size(); i != e; ++i)
      if (isInteger(TypeVec[i])) {
        SmallestInt = TypeVec[i];
        break;
      }
    for (unsigned i = 1, e = TypeVec.size(); i != e; ++i)
      if (isInteger(TypeVec[i]) && TypeVec[i] < SmallestInt)
        SmallestInt = TypeVec[i];
  
    MVT::SimpleValueType SmallestFP = MVT::LAST_VALUETYPE;
    for (unsigned i = 0, e = TypeVec.size(); i != e; ++i)
      if (isFloatingPoint(TypeVec[i])) {
        SmallestFP = TypeVec[i];
        break;
      }
    for (unsigned i = 1, e = TypeVec.size(); i != e; ++i)
      if (isFloatingPoint(TypeVec[i]) && TypeVec[i] < SmallestFP)
        SmallestFP = TypeVec[i];
  
    int OtherIntSize = 0;
    int OtherFPSize = 0;
    for (SmallVector<MVT::SimpleValueType, 2>::iterator TVI =
           Other.TypeVec.begin();
         TVI != Other.TypeVec.end();
         /* NULL */) {
      if (isInteger(*TVI)) {
        ++OtherIntSize;
        if (*TVI == SmallestInt) {
          TVI = Other.TypeVec.erase(TVI);
          --OtherIntSize;
          MadeChange = true;
          continue;
        }
      }
      else if (isFloatingPoint(*TVI)) {
        ++OtherFPSize;
        if (*TVI == SmallestFP) {
          TVI = Other.TypeVec.erase(TVI);
          --OtherFPSize;
          MadeChange = true;
          continue;
        }
      }
      ++TVI;
    }
  
    // If this is the only type in the large set, the constraint can never be
    // satisfied.
    if ((Other.hasIntegerTypes() && OtherIntSize == 0)
        || (Other.hasFloatingPointTypes() && OtherFPSize == 0))
      TP.error("Type inference contradiction found, '" +
               Other.getName() + "' has nothing larger than '" + getName() +"'!");
  
    // Okay, find the largest type in the Other set and remove it from the
    // current set.
    MVT::SimpleValueType LargestInt = MVT::Other;
    for (unsigned i = 0, e = Other.TypeVec.size(); i != e; ++i)
      if (isInteger(Other.TypeVec[i])) {
        LargestInt = Other.TypeVec[i];
        break;
      }
    for (unsigned i = 1, e = Other.TypeVec.size(); i != e; ++i)
      if (isInteger(Other.TypeVec[i]) && Other.TypeVec[i] > LargestInt)
        LargestInt = Other.TypeVec[i];
  
    MVT::SimpleValueType LargestFP = MVT::Other;
    for (unsigned i = 0, e = Other.TypeVec.size(); i != e; ++i)
      if (isFloatingPoint(Other.TypeVec[i])) {
        LargestFP = Other.TypeVec[i];
        break;
      }
    for (unsigned i = 1, e = Other.TypeVec.size(); i != e; ++i)
      if (isFloatingPoint(Other.TypeVec[i]) && Other.TypeVec[i] > LargestFP)
        LargestFP = Other.TypeVec[i];
  
    int IntSize = 0;
    int FPSize = 0;
    for (SmallVector<MVT::SimpleValueType, 2>::iterator TVI =
           TypeVec.begin();
         TVI != TypeVec.end();
         /* NULL */) {
      if (isInteger(*TVI)) {
        ++IntSize;
        if (*TVI == LargestInt) {
          TVI = TypeVec.erase(TVI);
          --IntSize;
          MadeChange = true;
          continue;
        }
      }
      else if (isFloatingPoint(*TVI)) {
        ++FPSize;
        if (*TVI == LargestFP) {
          TVI = TypeVec.erase(TVI);
          --FPSize;
          MadeChange = true;
          continue;
        }
      }
      ++TVI;
    }
  
    // If this is the only type in the small set, the constraint can never be
    // satisfied.
    if ((hasIntegerTypes() && IntSize == 0)
        || (hasFloatingPointTypes() && FPSize == 0))
      TP.error("Type inference contradiction found, '" +
               getName() + "' has nothing smaller than '" + Other.getName()+"'!");
  
    return MadeChange;
  }
  
  /// EnforceVectorEltTypeIs - 'this' is now constrainted to be a vector type
  /// whose element is specified by VTOperand.
  bool EEVT::TypeSet::EnforceVectorEltTypeIs(EEVT::TypeSet &VTOperand,
                                             TreePattern &TP) {
    // "This" must be a vector and "VTOperand" must be a scalar.
    bool MadeChange = false;
    MadeChange |= EnforceVector(TP);
    MadeChange |= VTOperand.EnforceScalar(TP);
  
    // If we know the vector type, it forces the scalar to agree.
    if (isConcrete()) {
      EVT IVT = getConcrete();
      IVT = IVT.getVectorElementType();
      return MadeChange |
        VTOperand.MergeInTypeInfo(IVT.getSimpleVT().SimpleTy, TP);
    }
  
    // If the scalar type is known, filter out vector types whose element types
    // disagree.
    if (!VTOperand.isConcrete())
      return MadeChange;
  
    MVT::SimpleValueType VT = VTOperand.getConcrete();
  
    TypeSet InputSet(*this);
  
    // Filter out all the types which don't have the right element type.
    for (unsigned i = 0; i != TypeVec.size(); ++i) {
      assert(isVector(TypeVec[i]) && "EnforceVector didn't work");
      if (EVT(TypeVec[i]).getVectorElementType().getSimpleVT().SimpleTy != VT) {
        TypeVec.erase(TypeVec.begin()+i--);
        MadeChange = true;
      }
    }
  
    if (TypeVec.empty())  // FIXME: Really want an SMLoc here!
      TP.error("Type inference contradiction found, forcing '" +
               InputSet.getName() + "' to have a vector element");
    return MadeChange;
  }
  
  /// EnforceVectorSubVectorTypeIs - 'this' is now constrainted to be a
  /// vector type specified by VTOperand.
  bool EEVT::TypeSet::EnforceVectorSubVectorTypeIs(EEVT::TypeSet &VTOperand,
                                                   TreePattern &TP) {
    // "This" must be a vector and "VTOperand" must be a vector.
    bool MadeChange = false;
    MadeChange |= EnforceVector(TP);
    MadeChange |= VTOperand.EnforceVector(TP);
  
    // "This" must be larger than "VTOperand."
    MadeChange |= VTOperand.EnforceSmallerThan(*this, TP);
  
    // If we know the vector type, it forces the scalar types to agree.
    if (isConcrete()) {
      EVT IVT = getConcrete();
      IVT = IVT.getVectorElementType();
  
      EEVT::TypeSet EltTypeSet(IVT.getSimpleVT().SimpleTy, TP);
      MadeChange |= VTOperand.EnforceVectorEltTypeIs(EltTypeSet, TP);
    } else if (VTOperand.isConcrete()) {
      EVT IVT = VTOperand.getConcrete();
      IVT = IVT.getVectorElementType();
  
      EEVT::TypeSet EltTypeSet(IVT.getSimpleVT().SimpleTy, TP);
      MadeChange |= EnforceVectorEltTypeIs(EltTypeSet, TP);
    }
  
    return MadeChange;
  }
  
  //===----------------------------------------------------------------------===//
  // Helpers for working with extended types.
  
  bool RecordPtrCmp::operator()(const Record *LHS, const Record *RHS) const {
    return LHS->getID() < RHS->getID();
  }
  
  /// Dependent variable map for CodeGenDAGPattern variant generation
  typedef std::map<std::string, int> DepVarMap;
  
  /// Const iterator shorthand for DepVarMap
  typedef DepVarMap::const_iterator DepVarMap_citer;
  
  static void FindDepVarsOf(TreePatternNode *N, DepVarMap &DepMap) {
    if (N->isLeaf()) {
      if (dynamic_cast<DefInit*>(N->getLeafValue()) != NULL)
        DepMap[N->getName()]++;
    } else {
      for (size_t i = 0, e = N->getNumChildren(); i != e; ++i)
        FindDepVarsOf(N->getChild(i), DepMap);
    }
  }
    
  /// Find dependent variables within child patterns
  static void FindDepVars(TreePatternNode *N, MultipleUseVarSet &DepVars) {
    DepVarMap depcounts;
    FindDepVarsOf(N, depcounts);
    for (DepVarMap_citer i = depcounts.begin(); i != depcounts.end(); ++i) {
      if (i->second > 1)            // std::pair<std::string, int>
        DepVars.insert(i->first);
    }
  }
  
  #ifndef NDEBUG
  /// Dump the dependent variable set:
  static void DumpDepVars(MultipleUseVarSet &DepVars) {
    if (DepVars.empty()) {
      DEBUG(errs() << "<empty set>");
    } else {
      DEBUG(errs() << "[ ");
      for (MultipleUseVarSet::const_iterator i = DepVars.begin(),
           e = DepVars.end(); i != e; ++i) {
        DEBUG(errs() << (*i) << " ");
      }
      DEBUG(errs() << "]");
    }
  }
  #endif
  
  
  //===----------------------------------------------------------------------===//
  // TreePredicateFn Implementation
  //===----------------------------------------------------------------------===//
  
  /// TreePredicateFn constructor.  Here 'N' is a subclass of PatFrag.
  TreePredicateFn::TreePredicateFn(TreePattern *N) : PatFragRec(N) {
    assert((getPredCode().empty() || getImmCode().empty()) &&
          ".td file corrupt: can't have a node predicate *and* an imm predicate");
  }
  
  std::string TreePredicateFn::getPredCode() const {
    return PatFragRec->getRecord()->getValueAsString("PredicateCode");
  }
  
  std::string TreePredicateFn::getImmCode() const {
    return PatFragRec->getRecord()->getValueAsString("ImmediateCode");
  }
  
  
  /// isAlwaysTrue - Return true if this is a noop predicate.
  bool TreePredicateFn::isAlwaysTrue() const {
    return getPredCode().empty() && getImmCode().empty();
  }
  
  /// Return the name to use in the generated code to reference this, this is
  /// "Predicate_foo" if from a pattern fragment "foo".
  std::string TreePredicateFn::getFnName() const {
    return "Predicate_" + PatFragRec->getRecord()->getName();
  }
  
  /// getCodeToRunOnSDNode - Return the code for the function body that
  /// evaluates this predicate.  The argument is expected to be in "Node",
  /// not N.  This handles casting and conversion to a concrete node type as
  /// appropriate.
  std::string TreePredicateFn::getCodeToRunOnSDNode() const {
    // Handle immediate predicates first.
    std::string ImmCode = getImmCode();
    if (!ImmCode.empty()) {
      std::string Result =
        "    int64_t Imm = cast<ConstantSDNode>(Node)->getSExtValue();\n";
      return Result + ImmCode;
    }
    
    // Handle arbitrary node predicates.
    assert(!getPredCode().empty() && "Don't have any predicate code!");
    std::string ClassName;
    if (PatFragRec->getOnlyTree()->isLeaf())
      ClassName = "SDNode";
    else {
      Record *Op = PatFragRec->getOnlyTree()->getOperator();
      ClassName = PatFragRec->getDAGPatterns().getSDNodeInfo(Op).getSDClassName();
    }
    std::string Result;
    if (ClassName == "SDNode")
      Result = "    SDNode *N = Node;\n";
    else
      Result = "    " + ClassName + "*N = cast<" + ClassName + ">(Node);\n";
    
    return Result + getPredCode();
  }
  
  //===----------------------------------------------------------------------===//
  // PatternToMatch implementation
  //
  
  
  /// getPatternSize - Return the 'size' of this pattern.  We want to match large
  /// patterns before small ones.  This is used to determine the size of a
  /// pattern.
  static unsigned getPatternSize(const TreePatternNode *P,
                                 const CodeGenDAGPatterns &CGP) {
    unsigned Size = 3;  // The node itself.
    // If the root node is a ConstantSDNode, increases its size.
    // e.g. (set R32:$dst, 0).
    if (P->isLeaf() && dynamic_cast<IntInit*>(P->getLeafValue()))
      Size += 2;
  
    // FIXME: This is a hack to statically increase the priority of patterns
    // which maps a sub-dag to a complex pattern. e.g. favors LEA over ADD.
    // Later we can allow complexity / cost for each pattern to be (optionally)
    // specified. To get best possible pattern match we'll need to dynamically
    // calculate the complexity of all patterns a dag can potentially map to.
    const ComplexPattern *AM = P->getComplexPatternInfo(CGP);
    if (AM)
      Size += AM->getNumOperands() * 3;
  
    // If this node has some predicate function that must match, it adds to the
    // complexity of this node.
    if (!P->getPredicateFns().empty())
      ++Size;
  
    // Count children in the count if they are also nodes.
    for (unsigned i = 0, e = P->getNumChildren(); i != e; ++i) {
      TreePatternNode *Child = P->getChild(i);
      if (!Child->isLeaf() && Child->getNumTypes() &&
          Child->getType(0) != MVT::Other)
        Size += getPatternSize(Child, CGP);
      else if (Child->isLeaf()) {
        if (dynamic_cast<IntInit*>(Child->getLeafValue()))
          Size += 5;  // Matches a ConstantSDNode (+3) and a specific value (+2).
        else if (Child->getComplexPatternInfo(CGP))
          Size += getPatternSize(Child, CGP);
        else if (!Child->getPredicateFns().empty())
          ++Size;
      }
    }
  
    return Size;
  }
  
  /// Compute the complexity metric for the input pattern.  This roughly
  /// corresponds to the number of nodes that are covered.
  unsigned PatternToMatch::
  getPatternComplexity(const CodeGenDAGPatterns &CGP) const {
    return getPatternSize(getSrcPattern(), CGP) + getAddedComplexity();
  }
  
  
  /// getPredicateCheck - Return a single string containing all of this
  /// pattern's predicates concatenated with "&&" operators.
  ///
  std::string PatternToMatch::getPredicateCheck() const {
    std::string PredicateCheck;
    for (unsigned i = 0, e = Predicates->getSize(); i != e; ++i) {
      if (DefInit *Pred = dynamic_cast<DefInit*>(Predicates->getElement(i))) {
        Record *Def = Pred->getDef();
        if (!Def->isSubClassOf("Predicate")) {
  #ifndef NDEBUG
          Def->dump();
  #endif
          llvm_unreachable("Unknown predicate type!");
        }
        if (!PredicateCheck.empty())
          PredicateCheck += " && ";
        PredicateCheck += "(" + Def->getValueAsString("CondString") + ")";
      }
    }
  
    return PredicateCheck;
  }
  
  //===----------------------------------------------------------------------===//
  // SDTypeConstraint implementation
  //
  
  SDTypeConstraint::SDTypeConstraint(Record *R) {
    OperandNo = R->getValueAsInt("OperandNum");
  
    if (R->isSubClassOf("SDTCisVT")) {
      ConstraintType = SDTCisVT;
      x.SDTCisVT_Info.VT = getValueType(R->getValueAsDef("VT"));
      if (x.SDTCisVT_Info.VT == MVT::isVoid)
        throw TGError(R->getLoc(), "Cannot use 'Void' as type to SDTCisVT");
  
    } else if (R->isSubClassOf("SDTCisPtrTy")) {
      ConstraintType = SDTCisPtrTy;
    } else if (R->isSubClassOf("SDTCisInt")) {
      ConstraintType = SDTCisInt;
    } else if (R->isSubClassOf("SDTCisFP")) {
      ConstraintType = SDTCisFP;
    } else if (R->isSubClassOf("SDTCisVec")) {
      ConstraintType = SDTCisVec;
    } else if (R->isSubClassOf("SDTCisSameAs")) {
      ConstraintType = SDTCisSameAs;
      x.SDTCisSameAs_Info.OtherOperandNum = R->getValueAsInt("OtherOperandNum");
    } else if (R->isSubClassOf("SDTCisVTSmallerThanOp")) {
      ConstraintType = SDTCisVTSmallerThanOp;
      x.SDTCisVTSmallerThanOp_Info.OtherOperandNum =
        R->getValueAsInt("OtherOperandNum");
    } else if (R->isSubClassOf("SDTCisOpSmallerThanOp")) {
      ConstraintType = SDTCisOpSmallerThanOp;
      x.SDTCisOpSmallerThanOp_Info.BigOperandNum =
        R->getValueAsInt("BigOperandNum");
    } else if (R->isSubClassOf("SDTCisEltOfVec")) {
      ConstraintType = SDTCisEltOfVec;
      x.SDTCisEltOfVec_Info.OtherOperandNum = R->getValueAsInt("OtherOpNum");
    } else if (R->isSubClassOf("SDTCisSubVecOfVec")) {
      ConstraintType = SDTCisSubVecOfVec;
      x.SDTCisSubVecOfVec_Info.OtherOperandNum =
        R->getValueAsInt("OtherOpNum");
    } else {
      errs() << "Unrecognized SDTypeConstraint '" << R->getName() << "'!\n";
      exit(1);
    }
  }
  
  /// getOperandNum - Return the node corresponding to operand #OpNo in tree
  /// N, and the result number in ResNo.
  static TreePatternNode *getOperandNum(unsigned OpNo, TreePatternNode *N,
                                        const SDNodeInfo &NodeInfo,
                                        unsigned &ResNo) {
    unsigned NumResults = NodeInfo.getNumResults();
    if (OpNo < NumResults) {
      ResNo = OpNo;
      return N;
    }
  
    OpNo -= NumResults;
  
    if (OpNo >= N->getNumChildren()) {
      errs() << "Invalid operand number in type constraint "
             << (OpNo+NumResults) << " ";
      N->dump();
      errs() << '\n';
      exit(1);
    }
  
    return N->getChild(OpNo);
  }
  
  /// ApplyTypeConstraint - Given a node in a pattern, apply this type
  /// constraint to the nodes operands.  This returns true if it makes a
  /// change, false otherwise.  If a type contradiction is found, throw an
  /// exception.
  bool SDTypeConstraint::ApplyTypeConstraint(TreePatternNode *N,
                                             const SDNodeInfo &NodeInfo,
                                             TreePattern &TP) const {
    unsigned ResNo = 0; // The result number being referenced.
    TreePatternNode *NodeToApply = getOperandNum(OperandNo, N, NodeInfo, ResNo);
  
    switch (ConstraintType) {
    case SDTCisVT:
      // Operand must be a particular type.
      return NodeToApply->UpdateNodeType(ResNo, x.SDTCisVT_Info.VT, TP);
    case SDTCisPtrTy:
      // Operand must be same as target pointer type.
      return NodeToApply->UpdateNodeType(ResNo, MVT::iPTR, TP);
    case SDTCisInt:
      // Require it to be one of the legal integer VTs.
      return NodeToApply->getExtType(ResNo).EnforceInteger(TP);
    case SDTCisFP:
      // Require it to be one of the legal fp VTs.
      return NodeToApply->getExtType(ResNo).EnforceFloatingPoint(TP);
    case SDTCisVec:
      // Require it to be one of the legal vector VTs.
      return NodeToApply->getExtType(ResNo).EnforceVector(TP);
    case SDTCisSameAs: {
      unsigned OResNo = 0;
      TreePatternNode *OtherNode =
        getOperandNum(x.SDTCisSameAs_Info.OtherOperandNum, N, NodeInfo, OResNo);
      return NodeToApply->UpdateNodeType(OResNo, OtherNode->getExtType(ResNo),TP)|
             OtherNode->UpdateNodeType(ResNo,NodeToApply->getExtType(OResNo),TP);
    }
    case SDTCisVTSmallerThanOp: {
      // The NodeToApply must be a leaf node that is a VT.  OtherOperandNum must
      // have an integer type that is smaller than the VT.
      if (!NodeToApply->isLeaf() ||
          !dynamic_cast<DefInit*>(NodeToApply->getLeafValue()) ||
          !static_cast<DefInit*>(NodeToApply->getLeafValue())->getDef()
                 ->isSubClassOf("ValueType"))
        TP.error(N->getOperator()->getName() + " expects a VT operand!");
      MVT::SimpleValueType VT =
       getValueType(static_cast<DefInit*>(NodeToApply->getLeafValue())->getDef());
  
      EEVT::TypeSet TypeListTmp(VT, TP);
  
      unsigned OResNo = 0;
      TreePatternNode *OtherNode =
        getOperandNum(x.SDTCisVTSmallerThanOp_Info.OtherOperandNum, N, NodeInfo,
                      OResNo);
  
      return TypeListTmp.EnforceSmallerThan(OtherNode->getExtType(OResNo), TP);
    }
    case SDTCisOpSmallerThanOp: {
      unsigned BResNo = 0;
      TreePatternNode *BigOperand =
        getOperandNum(x.SDTCisOpSmallerThanOp_Info.BigOperandNum, N, NodeInfo,
                      BResNo);
      return NodeToApply->getExtType(ResNo).
                    EnforceSmallerThan(BigOperand->getExtType(BResNo), TP);
    }
    case SDTCisEltOfVec: {
      unsigned VResNo = 0;
      TreePatternNode *VecOperand =
        getOperandNum(x.SDTCisEltOfVec_Info.OtherOperandNum, N, NodeInfo,
                      VResNo);
  
      // Filter vector types out of VecOperand that don't have the right element
      // type.
      return VecOperand->getExtType(VResNo).
        EnforceVectorEltTypeIs(NodeToApply->getExtType(ResNo), TP);
    }
    case SDTCisSubVecOfVec: {
      unsigned VResNo = 0;
      TreePatternNode *BigVecOperand =
        getOperandNum(x.SDTCisSubVecOfVec_Info.OtherOperandNum, N, NodeInfo,
                      VResNo);
  
      // Filter vector types out of BigVecOperand that don't have the
      // right subvector type.
      return BigVecOperand->getExtType(VResNo).
        EnforceVectorSubVectorTypeIs(NodeToApply->getExtType(ResNo), TP);
    }
    }
    llvm_unreachable("Invalid ConstraintType!");
  }
  
  //===----------------------------------------------------------------------===//
  // SDNodeInfo implementation
  //
  SDNodeInfo::SDNodeInfo(Record *R) : Def(R) {
    EnumName    = R->getValueAsString("Opcode");
    SDClassName = R->getValueAsString("SDClass");
    Record *TypeProfile = R->getValueAsDef("TypeProfile");
    NumResults = TypeProfile->getValueAsInt("NumResults");
    NumOperands = TypeProfile->getValueAsInt("NumOperands");
  
    // Parse the properties.
    Properties = 0;
    std::vector<Record*> PropList = R->getValueAsListOfDefs("Properties");
    for (unsigned i = 0, e = PropList.size(); i != e; ++i) {
      if (PropList[i]->getName() == "SDNPCommutative") {
        Properties |= 1 << SDNPCommutative;
      } else if (PropList[i]->getName() == "SDNPAssociative") {
        Properties |= 1 << SDNPAssociative;
      } else if (PropList[i]->getName() == "SDNPHasChain") {
        Properties |= 1 << SDNPHasChain;
      } else if (PropList[i]->getName() == "SDNPOutGlue") {
        Properties |= 1 << SDNPOutGlue;
      } else if (PropList[i]->getName() == "SDNPInGlue") {
        Properties |= 1 << SDNPInGlue;
      } else if (PropList[i]->getName() == "SDNPOptInGlue") {
        Properties |= 1 << SDNPOptInGlue;
      } else if (PropList[i]->getName() == "SDNPMayStore") {
        Properties |= 1 << SDNPMayStore;
      } else if (PropList[i]->getName() == "SDNPMayLoad") {
        Properties |= 1 << SDNPMayLoad;
      } else if (PropList[i]->getName() == "SDNPSideEffect") {
        Properties |= 1 << SDNPSideEffect;
      } else if (PropList[i]->getName() == "SDNPMemOperand") {
        Properties |= 1 << SDNPMemOperand;
      } else if (PropList[i]->getName() == "SDNPVariadic") {
        Properties |= 1 << SDNPVariadic;
      } else {
        errs() << "Unknown SD Node property '" << PropList[i]->getName()
               << "' on node '" << R->getName() << "'!\n";
        exit(1);
      }
    }
  
  
    // Parse the type constraints.
    std::vector<Record*> ConstraintList =
      TypeProfile->getValueAsListOfDefs("Constraints");
    TypeConstraints.assign(ConstraintList.begin(), ConstraintList.end());
  }
  
  /// getKnownType - If the type constraints on this node imply a fixed type
  /// (e.g. all stores return void, etc), then return it as an
  /// MVT::SimpleValueType.  Otherwise, return EEVT::Other.
  MVT::SimpleValueType SDNodeInfo::getKnownType(unsigned ResNo) const {
    unsigned NumResults = getNumResults();
    assert(NumResults <= 1 &&
           "We only work with nodes with zero or one result so far!");
    assert(ResNo == 0 && "Only handles single result nodes so far");
  
    for (unsigned i = 0, e = TypeConstraints.size(); i != e; ++i) {
      // Make sure that this applies to the correct node result.
      if (TypeConstraints[i].OperandNo >= NumResults)  // FIXME: need value #
        continue;
  
      switch (TypeConstraints[i].ConstraintType) {
      default: break;
      case SDTypeConstraint::SDTCisVT:
        return TypeConstraints[i].x.SDTCisVT_Info.VT;
      case SDTypeConstraint::SDTCisPtrTy:
        return MVT::iPTR;
      }
    }
    return MVT::Other;
  }
  
  //===----------------------------------------------------------------------===//
  // TreePatternNode implementation
  //
  
  TreePatternNode::~TreePatternNode() {
  #if 0 // FIXME: implement refcounted tree nodes!
    for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
      delete getChild(i);
  #endif
  }
  
  static unsigned GetNumNodeResults(Record *Operator, CodeGenDAGPatterns &CDP) {
    if (Operator->getName() == "set" ||
        Operator->getName() == "implicit")
      return 0;  // All return nothing.
  
    if (Operator->isSubClassOf("Intrinsic"))
      return CDP.getIntrinsic(Operator).IS.RetVTs.size();
  
    if (Operator->isSubClassOf("SDNode"))
      return CDP.getSDNodeInfo(Operator).getNumResults();
  
    if (Operator->isSubClassOf("PatFrag")) {
      // If we've already parsed this pattern fragment, get it.  Otherwise, handle
      // the forward reference case where one pattern fragment references another
      // before it is processed.
      if (TreePattern *PFRec = CDP.getPatternFragmentIfRead(Operator))
        return PFRec->getOnlyTree()->getNumTypes();
  
      // Get the result tree.
      DagInit *Tree = Operator->getValueAsDag("Fragment");
      Record *Op = 0;
      if (Tree && dynamic_cast<DefInit*>(Tree->getOperator()))
        Op = dynamic_cast<DefInit*>(Tree->getOperator())->getDef();
      assert(Op && "Invalid Fragment");
      return GetNumNodeResults(Op, CDP);
    }
  
    if (Operator->isSubClassOf("Instruction")) {
      CodeGenInstruction &InstInfo = CDP.getTargetInfo().getInstruction(Operator);
  
      // FIXME: Should allow access to all the results here.
      unsigned NumDefsToAdd = InstInfo.Operands.NumDefs ? 1 : 0;
  
      // Add on one implicit def if it has a resolvable type.
      if (InstInfo.HasOneImplicitDefWithKnownVT(CDP.getTargetInfo()) !=MVT::Other)
        ++NumDefsToAdd;
      return NumDefsToAdd;
    }
  
    if (Operator->isSubClassOf("SDNodeXForm"))
      return 1;  // FIXME: Generalize SDNodeXForm
  
    Operator->dump();
    errs() << "Unhandled node in GetNumNodeResults\n";
    exit(1);
  }
  
  void TreePatternNode::print(raw_ostream &OS) const {
    if (isLeaf())
      OS << *getLeafValue();
    else
      OS << '(' << getOperator()->getName();
  
    for (unsigned i = 0, e = Types.size(); i != e; ++i)
      OS << ':' << getExtType(i).getName();
  
    if (!isLeaf()) {
      if (getNumChildren() != 0) {
        OS << " ";
        getChild(0)->print(OS);
        for (unsigned i = 1, e = getNumChildren(); i != e; ++i) {
          OS << ", ";
          getChild(i)->print(OS);
        }
      }
      OS << ")";
    }
  
    for (unsigned i = 0, e = PredicateFns.size(); i != e; ++i)
      OS << "<<P:" << PredicateFns[i].getFnName() << ">>";
    if (TransformFn)
      OS << "<<X:" << TransformFn->getName() << ">>";
    if (!getName().empty())
      OS << ":$" << getName();
  
  }
  void TreePatternNode::dump() const {
    print(errs());
  }
  
  /// isIsomorphicTo - Return true if this node is recursively
  /// isomorphic to the specified node.  For this comparison, the node's
  /// entire state is considered. The assigned name is ignored, since
  /// nodes with differing names are considered isomorphic. However, if
  /// the assigned name is present in the dependent variable set, then
  /// the assigned name is considered significant and the node is
  /// isomorphic if the names match.
  bool TreePatternNode::isIsomorphicTo(const TreePatternNode *N,
                                       const MultipleUseVarSet &DepVars) const {
    if (N == this) return true;
    if (N->isLeaf() != isLeaf() || getExtTypes() != N->getExtTypes() ||
        getPredicateFns() != N->getPredicateFns() ||
        getTransformFn() != N->getTransformFn())
      return false;
  
    if (isLeaf()) {
      if (DefInit *DI = dynamic_cast<DefInit*>(getLeafValue())) {
        if (DefInit *NDI = dynamic_cast<DefInit*>(N->getLeafValue())) {
          return ((DI->getDef() == NDI->getDef())
                  && (DepVars.find(getName()) == DepVars.end()
                      || getName() == N->getName()));
        }
      }
      return getLeafValue() == N->getLeafValue();
    }
  
    if (N->getOperator() != getOperator() ||
        N->getNumChildren() != getNumChildren()) return false;
    for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
      if (!getChild(i)->isIsomorphicTo(N->getChild(i), DepVars))
        return false;
    return true;
  }
  
  /// clone - Make a copy of this tree and all of its children.
  ///
  TreePatternNode *TreePatternNode::clone() const {
    TreePatternNode *New;
    if (isLeaf()) {
      New = new TreePatternNode(getLeafValue(), getNumTypes());
    } else {
      std::vector<TreePatternNode*> CChildren;
      CChildren.reserve(Children.size());
      for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
        CChildren.push_back(getChild(i)->clone());
      New = new TreePatternNode(getOperator(), CChildren, getNumTypes());
    }
    New->setName(getName());
    New->Types = Types;
    New->setPredicateFns(getPredicateFns());
    New->setTransformFn(getTransformFn());
    return New;
  }
  
  /// RemoveAllTypes - Recursively strip all the types of this tree.
  void TreePatternNode::RemoveAllTypes() {
    for (unsigned i = 0, e = Types.size(); i != e; ++i)
      Types[i] = EEVT::TypeSet();  // Reset to unknown type.
    if (isLeaf()) return;
    for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
      getChild(i)->RemoveAllTypes();
  }
  
  
  /// SubstituteFormalArguments - Replace the formal arguments in this tree
  /// with actual values specified by ArgMap.
  void TreePatternNode::
  SubstituteFormalArguments(std::map<std::string, TreePatternNode*> &ArgMap) {
    if (isLeaf()) return;
  
    for (unsigned i = 0, e = getNumChildren(); i != e; ++i) {
      TreePatternNode *Child = getChild(i);
      if (Child->isLeaf()) {
        Init *Val = Child->getLeafValue();
        if (dynamic_cast<DefInit*>(Val) &&
            static_cast<DefInit*>(Val)->getDef()->getName() == "node") {
          // We found a use of a formal argument, replace it with its value.
          TreePatternNode *NewChild = ArgMap[Child->getName()];
          assert(NewChild && "Couldn't find formal argument!");
          assert((Child->getPredicateFns().empty() ||
                  NewChild->getPredicateFns() == Child->getPredicateFns()) &&
                 "Non-empty child predicate clobbered!");
          setChild(i, NewChild);
        }
      } else {
        getChild(i)->SubstituteFormalArguments(ArgMap);
      }
    }
  }
  
  
  /// InlinePatternFragments - If this pattern refers to any pattern
  /// fragments, inline them into place, giving us a pattern without any
  /// PatFrag references.
  TreePatternNode *TreePatternNode::InlinePatternFragments(TreePattern &TP) {
    if (isLeaf()) return this;  // nothing to do.
    Record *Op = getOperator();
  
    if (!Op->isSubClassOf("PatFrag")) {
      // Just recursively inline children nodes.
      for (unsigned i = 0, e = getNumChildren(); i != e; ++i) {
        TreePatternNode *Child = getChild(i);
        TreePatternNode *NewChild = Child->InlinePatternFragments(TP);
  
        assert((Child->getPredicateFns().empty() ||
                NewChild->getPredicateFns() == Child->getPredicateFns()) &&
               "Non-empty child predicate clobbered!");
  
        setChild(i, NewChild);
      }
      return this;
    }
  
    // Otherwise, we found a reference to a fragment.  First, look up its
    // TreePattern record.
    TreePattern *Frag = TP.getDAGPatterns().getPatternFragment(Op);
  
    // Verify that we are passing the right number of operands.
    if (Frag->getNumArgs() != Children.size())
      TP.error("'" + Op->getName() + "' fragment requires " +
               utostr(Frag->getNumArgs()) + " operands!");
  
    TreePatternNode *FragTree = Frag->getOnlyTree()->clone();
  
    TreePredicateFn PredFn(Frag);
    if (!PredFn.isAlwaysTrue())
      FragTree->addPredicateFn(PredFn);
  
    // Resolve formal arguments to their actual value.
    if (Frag->getNumArgs()) {
      // Compute the map of formal to actual arguments.
      std::map<std::string, TreePatternNode*> ArgMap;
      for (unsigned i = 0, e = Frag->getNumArgs(); i != e; ++i)
        ArgMap[Frag->getArgName(i)] = getChild(i)->InlinePatternFragments(TP);
  
      FragTree->SubstituteFormalArguments(ArgMap);
    }
  
    FragTree->setName(getName());
    for (unsigned i = 0, e = Types.size(); i != e; ++i)
      FragTree->UpdateNodeType(i, getExtType(i), TP);
  
    // Transfer in the old predicates.
    for (unsigned i = 0, e = getPredicateFns().size(); i != e; ++i)
      FragTree->addPredicateFn(getPredicateFns()[i]);
  
    // Get a new copy of this fragment to stitch into here.
    //delete this;    // FIXME: implement refcounting!
  
    // The fragment we inlined could have recursive inlining that is needed.  See
    // if there are any pattern fragments in it and inline them as needed.
    return FragTree->InlinePatternFragments(TP);
  }
  
  /// getImplicitType - Check to see if the specified record has an implicit
  /// type which should be applied to it.  This will infer the type of register
  /// references from the register file information, for example.
  ///
  static EEVT::TypeSet getImplicitType(Record *R, unsigned ResNo,
                                       bool NotRegisters, TreePattern &TP) {
    // Check to see if this is a register operand.
    if (R->isSubClassOf("RegisterOperand")) {
      assert(ResNo == 0 && "Regoperand ref only has one result!");
      if (NotRegisters)
        return EEVT::TypeSet(); // Unknown.
      Record *RegClass = R->getValueAsDef("RegClass");
      const CodeGenTarget &T = TP.getDAGPatterns().getTargetInfo();
      return EEVT::TypeSet(T.getRegisterClass(RegClass).getValueTypes());
    }
  
    // Check to see if this is a register or a register class.
    if (R->isSubClassOf("RegisterClass")) {
      assert(ResNo == 0 && "Regclass ref only has one result!");
      if (NotRegisters)
        return EEVT::TypeSet(); // Unknown.
      const CodeGenTarget &T = TP.getDAGPatterns().getTargetInfo();
      return EEVT::TypeSet(T.getRegisterClass(R).getValueTypes());
    }
  
    if (R->isSubClassOf("PatFrag")) {
      assert(ResNo == 0 && "FIXME: PatFrag with multiple results?");
      // Pattern fragment types will be resolved when they are inlined.
      return EEVT::TypeSet(); // Unknown.
    }
  
    if (R->isSubClassOf("Register")) {
      assert(ResNo == 0 && "Registers only produce one result!");
      if (NotRegisters)
        return EEVT::TypeSet(); // Unknown.
      const CodeGenTarget &T = TP.getDAGPatterns().getTargetInfo();
      return EEVT::TypeSet(T.getRegisterVTs(R));
    }
  
    if (R->isSubClassOf("SubRegIndex")) {
      assert(ResNo == 0 && "SubRegisterIndices only produce one result!");
      return EEVT::TypeSet();
    }
  
    if (R->isSubClassOf("ValueType") || R->isSubClassOf("CondCode")) {
      assert(ResNo == 0 && "This node only has one result!");
      // Using a VTSDNode or CondCodeSDNode.
      return EEVT::TypeSet(MVT::Other, TP);
    }
  
    if (R->isSubClassOf("ComplexPattern")) {
      assert(ResNo == 0 && "FIXME: ComplexPattern with multiple results?");
      if (NotRegisters)
        return EEVT::TypeSet(); // Unknown.
     return EEVT::TypeSet(TP.getDAGPatterns().getComplexPattern(R).getValueType(),
                           TP);
    }
    if (R->isSubClassOf("PointerLikeRegClass")) {
      assert(ResNo == 0 && "Regclass can only have one result!");
      return EEVT::TypeSet(MVT::iPTR, TP);
    }
  
    if (R->getName() == "node" || R->getName() == "srcvalue" ||
        R->getName() == "zero_reg") {
      // Placeholder.
      return EEVT::TypeSet(); // Unknown.
    }
  
    TP.error("Unknown node flavor used in pattern: " + R->getName());
    return EEVT::TypeSet(MVT::Other, TP);
  }
  
  
  /// getIntrinsicInfo - If this node corresponds to an intrinsic, return the
  /// CodeGenIntrinsic information for it, otherwise return a null pointer.
  const CodeGenIntrinsic *TreePatternNode::
  getIntrinsicInfo(const CodeGenDAGPatterns &CDP) const {
    if (getOperator() != CDP.get_intrinsic_void_sdnode() &&
        getOperator() != CDP.get_intrinsic_w_chain_sdnode() &&
        getOperator() != CDP.get_intrinsic_wo_chain_sdnode())
      return 0;
  
    unsigned IID =
      dynamic_cast<IntInit*>(getChild(0)->getLeafValue())->getValue();
    return &CDP.getIntrinsicInfo(IID);
  }
  
  /// getComplexPatternInfo - If this node corresponds to a ComplexPattern,
  /// return the ComplexPattern information, otherwise return null.
  const ComplexPattern *
  TreePatternNode::getComplexPatternInfo(const CodeGenDAGPatterns &CGP) const {
    if (!isLeaf()) return 0;
  
    DefInit *DI = dynamic_cast<DefInit*>(getLeafValue());
    if (DI && DI->getDef()->isSubClassOf("ComplexPattern"))
      return &CGP.getComplexPattern(DI->getDef());
    return 0;
  }
  
  /// NodeHasProperty - Return true if this node has the specified property.
  bool TreePatternNode::NodeHasProperty(SDNP Property,
                                        const CodeGenDAGPatterns &CGP) const {
    if (isLeaf()) {
      if (const ComplexPattern *CP = getComplexPatternInfo(CGP))
        return CP->hasProperty(Property);
      return false;
    }
  
    Record *Operator = getOperator();
    if (!Operator->isSubClassOf("SDNode")) return false;
  
    return CGP.getSDNodeInfo(Operator).hasProperty(Property);
  }
  
  
  
  
  /// TreeHasProperty - Return true if any node in this tree has the specified
  /// property.
  bool TreePatternNode::TreeHasProperty(SDNP Property,
                                        const CodeGenDAGPatterns &CGP) const {
    if (NodeHasProperty(Property, CGP))
      return true;
    for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
      if (getChild(i)->TreeHasProperty(Property, CGP))
        return true;
    return false;
  }
  
  /// isCommutativeIntrinsic - Return true if the node corresponds to a
  /// commutative intrinsic.
  bool
  TreePatternNode::isCommutativeIntrinsic(const CodeGenDAGPatterns &CDP) const {
    if (const CodeGenIntrinsic *Int = getIntrinsicInfo(CDP))
      return Int->isCommutative;
    return false;
  }
  
  
  /// ApplyTypeConstraints - Apply all of the type constraints relevant to
  /// this node and its children in the tree.  This returns true if it makes a
  /// change, false otherwise.  If a type contradiction is found, throw an
  /// exception.
  bool TreePatternNode::ApplyTypeConstraints(TreePattern &TP, bool NotRegisters) {
    CodeGenDAGPatterns &CDP = TP.getDAGPatterns();
    if (isLeaf()) {
      if (DefInit *DI = dynamic_cast<DefInit*>(getLeafValue())) {
        // If it's a regclass or something else known, include the type.
        bool MadeChange = false;
        for (unsigned i = 0, e = Types.size(); i != e; ++i)
          MadeChange |= UpdateNodeType(i, getImplicitType(DI->getDef(), i,
                                                          NotRegisters, TP), TP);
        return MadeChange;
      }
  
      if (IntInit *II = dynamic_cast<IntInit*>(getLeafValue())) {
        assert(Types.size() == 1 && "Invalid IntInit");
  
        // Int inits are always integers. :)
        bool MadeChange = Types[0].EnforceInteger(TP);
  
        if (!Types[0].isConcrete())
          return MadeChange;
  
        MVT::SimpleValueType VT = getType(0);
        if (VT == MVT::iPTR || VT == MVT::iPTRAny)
          return MadeChange;
  
        unsigned Size = EVT(VT).getSizeInBits();
        // Make sure that the value is representable for this type.
        if (Size >= 32) return MadeChange;
  
        int Val = (II->getValue() << (32-Size)) >> (32-Size);
        if (Val == II->getValue()) return MadeChange;
  
        // If sign-extended doesn't fit, does it fit as unsigned?
        unsigned ValueMask;
        unsigned UnsignedVal;
        ValueMask = unsigned(~uint32_t(0UL) >> (32-Size));
        UnsignedVal = unsigned(II->getValue());
  
        if ((ValueMask & UnsignedVal) == UnsignedVal)
          return MadeChange;
  
        TP.error("Integer value '" + itostr(II->getValue())+
                 "' is out of range for type '" + getEnumName(getType(0)) + "'!");
        return MadeChange;
      }
      return false;
    }
  
    // special handling for set, which isn't really an SDNode.
    if (getOperator()->getName() == "set") {
      assert(getNumTypes() == 0 && "Set doesn't produce a value");
      assert(getNumChildren() >= 2 && "Missing RHS of a set?");
      unsigned NC = getNumChildren();
  
      TreePatternNode *SetVal = getChild(NC-1);
      bool MadeChange = SetVal->ApplyTypeConstraints(TP, NotRegisters);
  
      for (unsigned i = 0; i < NC-1; ++i) {
        TreePatternNode *Child = getChild(i);
        MadeChange |= Child->ApplyTypeConstraints(TP, NotRegisters);
  
        // Types of operands must match.
        MadeChange |= Child->UpdateNodeType(0, SetVal->getExtType(i), TP);
        MadeChange |= SetVal->UpdateNodeType(i, Child->getExtType(0), TP);
      }
      return MadeChange;
    }
  
    if (getOperator()->getName() == "implicit") {
      assert(getNumTypes() == 0 && "Node doesn't produce a value");
  
      bool MadeChange = false;
      for (unsigned i = 0; i < getNumChildren(); ++i)
        MadeChange = getChild(i)->ApplyTypeConstraints(TP, NotRegisters);
      return MadeChange;
    }
  
    if (getOperator()->getName() == "COPY_TO_REGCLASS") {
      bool MadeChange = false;
      MadeChange |= getChild(0)->ApplyTypeConstraints(TP, NotRegisters);
      MadeChange |= getChild(1)->ApplyTypeConstraints(TP, NotRegisters);
  
      assert(getChild(0)->getNumTypes() == 1 &&
             getChild(1)->getNumTypes() == 1 && "Unhandled case");
  
      // child #1 of COPY_TO_REGCLASS should be a register class.  We don't care
      // what type it gets, so if it didn't get a concrete type just give it the
      // first viable type from the reg class.
      if (!getChild(1)->hasTypeSet(0) &&
          !getChild(1)->getExtType(0).isCompletelyUnknown()) {
        MVT::SimpleValueType RCVT = getChild(1)->getExtType(0).getTypeList()[0];
        MadeChange |= getChild(1)->UpdateNodeType(0, RCVT, TP);
      }
      return MadeChange;
    }
  
    if (const CodeGenIntrinsic *Int = getIntrinsicInfo(CDP)) {
      bool MadeChange = false;
  
      // Apply the result type to the node.
      unsigned NumRetVTs = Int->IS.RetVTs.size();
      unsigned NumParamVTs = Int->IS.ParamVTs.size();
  
      for (unsigned i = 0, e = NumRetVTs; i != e; ++i)
        MadeChange |= UpdateNodeType(i, Int->IS.RetVTs[i], TP);
  
      if (getNumChildren() != NumParamVTs + 1)
        TP.error("Intrinsic '" + Int->Name + "' expects " +
                 utostr(NumParamVTs) + " operands, not " +
                 utostr(getNumChildren() - 1) + " operands!");
  
      // Apply type info to the intrinsic ID.
      MadeChange |= getChild(0)->UpdateNodeType(0, MVT::iPTR, TP);
  
      for (unsigned i = 0, e = getNumChildren()-1; i != e; ++i) {
        MadeChange |= getChild(i+1)->ApplyTypeConstraints(TP, NotRegisters);
  
        MVT::SimpleValueType OpVT = Int->IS.ParamVTs[i];
        assert(getChild(i+1)->getNumTypes() == 1 && "Unhandled case");
        MadeChange |= getChild(i+1)->UpdateNodeType(0, OpVT, TP);
      }
      return MadeChange;
    }
  
    if (getOperator()->isSubClassOf("SDNode")) {
      const SDNodeInfo &NI = CDP.getSDNodeInfo(getOperator());
  
      // Check that the number of operands is sane.  Negative operands -> varargs.
      if (NI.getNumOperands() >= 0 &&
          getNumChildren() != (unsigned)NI.getNumOperands())
        TP.error(getOperator()->getName() + " node requires exactly " +
                 itostr(NI.getNumOperands()) + " operands!");
  
      bool MadeChange = NI.ApplyTypeConstraints(this, TP);
      for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
        MadeChange |= getChild(i)->ApplyTypeConstraints(TP, NotRegisters);
      return MadeChange;
    }
  
    if (getOperator()->isSubClassOf("Instruction")) {
      const DAGInstruction &Inst = CDP.getInstruction(getOperator());
      CodeGenInstruction &InstInfo =
        CDP.getTargetInfo().getInstruction(getOperator());
  
      bool MadeChange = false;
  
      // Apply the result types to the node, these come from the things in the
      // (outs) list of the instruction.
      // FIXME: Cap at one result so far.
      unsigned NumResultsToAdd = InstInfo.Operands.NumDefs ? 1 : 0;
      for (unsigned ResNo = 0; ResNo != NumResultsToAdd; ++ResNo) {
        Record *ResultNode = Inst.getResult(ResNo);
  
        if (ResultNode->isSubClassOf("PointerLikeRegClass")) {
          MadeChange |= UpdateNodeType(ResNo, MVT::iPTR, TP);
        } else if (ResultNode->isSubClassOf("RegisterOperand")) {
          Record *RegClass = ResultNode->getValueAsDef("RegClass");
          const CodeGenRegisterClass &RC =
            CDP.getTargetInfo().getRegisterClass(RegClass);
          MadeChange |= UpdateNodeType(ResNo, RC.getValueTypes(), TP);
        } else if (ResultNode->getName() == "unknown") {
          // Nothing to do.
        } else {
          assert(ResultNode->isSubClassOf("RegisterClass") &&
                 "Operands should be register classes!");
          const CodeGenRegisterClass &RC =
            CDP.getTargetInfo().getRegisterClass(ResultNode);
          MadeChange |= UpdateNodeType(ResNo, RC.getValueTypes(), TP);
        }
      }
  
      // If the instruction has implicit defs, we apply the first one as a result.
      // FIXME: This sucks, it should apply all implicit defs.
      if (!InstInfo.ImplicitDefs.empty()) {
        unsigned ResNo = NumResultsToAdd;
  
        // FIXME: Generalize to multiple possible types and multiple possible
        // ImplicitDefs.
        MVT::SimpleValueType VT =
          InstInfo.HasOneImplicitDefWithKnownVT(CDP.getTargetInfo());
  
        if (VT != MVT::Other)
          MadeChange |= UpdateNodeType(ResNo, VT, TP);
      }
  
      // If this is an INSERT_SUBREG, constrain the source and destination VTs to
      // be the same.
      if (getOperator()->getName() == "INSERT_SUBREG") {
        assert(getChild(0)->getNumTypes() == 1 && "FIXME: Unhandled");
        MadeChange |= UpdateNodeType(0, getChild(0)->getExtType(0), TP);
        MadeChange |= getChild(0)->UpdateNodeType(0, getExtType(0), TP);
      }
  
      unsigned ChildNo = 0;
      for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i) {
        Record *OperandNode = Inst.getOperand(i);
  
        // If the instruction expects a predicate or optional def operand, we
        // codegen this by setting the operand to it's default value if it has a
        // non-empty DefaultOps field.
        if ((OperandNode->isSubClassOf("PredicateOperand") ||
             OperandNode->isSubClassOf("OptionalDefOperand")) &&
            !CDP.getDefaultOperand(OperandNode).DefaultOps.empty())
          continue;
  
        // Verify that we didn't run out of provided operands.
        if (ChildNo >= getNumChildren())
          TP.error("Instruction '" + getOperator()->getName() +
                   "' expects more operands than were provided.");
  
        MVT::SimpleValueType VT;
        TreePatternNode *Child = getChild(ChildNo++);
        unsigned ChildResNo = 0;  // Instructions always use res #0 of their op.
  
        if (OperandNode->isSubClassOf("RegisterClass")) {
          const CodeGenRegisterClass &RC =
            CDP.getTargetInfo().getRegisterClass(OperandNode);
          MadeChange |= Child->UpdateNodeType(ChildResNo, RC.getValueTypes(), TP);
        } else if (OperandNode->isSubClassOf("RegisterOperand")) {
          Record *RegClass = OperandNode->getValueAsDef("RegClass");
          const CodeGenRegisterClass &RC =
            CDP.getTargetInfo().getRegisterClass(RegClass);
          MadeChange |= Child->UpdateNodeType(ChildResNo, RC.getValueTypes(), TP);
        } else if (OperandNode->isSubClassOf("Operand")) {
          VT = getValueType(OperandNode->getValueAsDef("Type"));
          MadeChange |= Child->UpdateNodeType(ChildResNo, VT, TP);
        } else if (OperandNode->isSubClassOf("PointerLikeRegClass")) {
          MadeChange |= Child->UpdateNodeType(ChildResNo, MVT::iPTR, TP);
        } else if (OperandNode->getName() == "unknown") {
          // Nothing to do.
        } else
          llvm_unreachable("Unknown operand type!");
  
        MadeChange |= Child->ApplyTypeConstraints(TP, NotRegisters);
      }
  
      if (ChildNo != getNumChildren())
        TP.error("Instruction '" + getOperator()->getName() +
                 "' was provided too many operands!");
  
      return MadeChange;
    }
  
    assert(getOperator()->isSubClassOf("SDNodeXForm") && "Unknown node type!");
  
    // Node transforms always take one operand.
    if (getNumChildren() != 1)
      TP.error("Node transform '" + getOperator()->getName() +
               "' requires one operand!");
  
    bool MadeChange = getChild(0)->ApplyTypeConstraints(TP, NotRegisters);
  
  
    // If either the output or input of the xform does not have exact
    // type info. We assume they must be the same. Otherwise, it is perfectly
    // legal to transform from one type to a completely different type.
  #if 0
    if (!hasTypeSet() || !getChild(0)->hasTypeSet()) {
      bool MadeChange = UpdateNodeType(getChild(0)->getExtType(), TP);
      MadeChange |= getChild(0)->UpdateNodeType(getExtType(), TP);
      return MadeChange;
    }
  #endif
    return MadeChange;
  }
  
  /// OnlyOnRHSOfCommutative - Return true if this value is only allowed on the
  /// RHS of a commutative operation, not the on LHS.
  static bool OnlyOnRHSOfCommutative(TreePatternNode *N) {
    if (!N->isLeaf() && N->getOperator()->getName() == "imm")
      return true;
    if (N->isLeaf() && dynamic_cast<IntInit*>(N->getLeafValue()))
      return true;
    return false;
  }
  
  
  /// canPatternMatch - If it is impossible for this pattern to match on this
  /// target, fill in Reason and return false.  Otherwise, return true.  This is
  /// used as a sanity check for .td files (to prevent people from writing stuff
  /// that can never possibly work), and to prevent the pattern permuter from
  /// generating stuff that is useless.
  bool TreePatternNode::canPatternMatch(std::string &Reason,
                                        const CodeGenDAGPatterns &CDP) {
    if (isLeaf()) return true;
  
    for (unsigned i = 0, e = getNumChildren(); i != e; ++i)
      if (!getChild(i)->canPatternMatch(Reason, CDP))
        return false;
  
    // If this is an intrinsic, handle cases that would make it not match.  For
    // example, if an operand is required to be an immediate.
    if (getOperator()->isSubClassOf("Intrinsic")) {
      // TODO:
      return true;
    }
  
    // If this node is a commutative operator, check that the LHS isn't an
    // immediate.
    const SDNodeInfo &NodeInfo = CDP.getSDNodeInfo(getOperator());
    bool isCommIntrinsic = isCommutativeIntrinsic(CDP);
    if (NodeInfo.hasProperty(SDNPCommutative) || isCommIntrinsic) {
      // Scan all of the operands of the node and make sure that only the last one
      // is a constant node, unless the RHS also is.
      if (!OnlyOnRHSOfCommutative(getChild(getNumChildren()-1))) {
        bool Skip = isCommIntrinsic ? 1 : 0; // First operand is intrinsic id.
        for (unsigned i = Skip, e = getNumChildren()-1; i != e; ++i)
          if (OnlyOnRHSOfCommutative(getChild(i))) {
            Reason="Immediate value must be on the RHS of commutative operators!";
            return false;
          }
      }
    }
  
    return true;
  }
  
  //===----------------------------------------------------------------------===//
  // TreePattern implementation
  //
  
  TreePattern::TreePattern(Record *TheRec, ListInit *RawPat, bool isInput,
                           CodeGenDAGPatterns &cdp) : TheRecord(TheRec), CDP(cdp){
    isInputPattern = isInput;
    for (unsigned i = 0, e = RawPat->getSize(); i != e; ++i)
      Trees.push_back(ParseTreePattern(RawPat->getElement(i), ""));
  }
  
  TreePattern::TreePattern(Record *TheRec, DagInit *Pat, bool isInput,
                           CodeGenDAGPatterns &cdp) : TheRecord(TheRec), CDP(cdp){
    isInputPattern = isInput;
    Trees.push_back(ParseTreePattern(Pat, ""));
  }
  
  TreePattern::TreePattern(Record *TheRec, TreePatternNode *Pat, bool isInput,
                           CodeGenDAGPatterns &cdp) : TheRecord(TheRec), CDP(cdp){
    isInputPattern = isInput;
    Trees.push_back(Pat);
  }
  
  void TreePattern::error(const std::string &Msg) const {
    dump();
    throw TGError(TheRecord->getLoc(), "In " + TheRecord->getName() + ": " + Msg);
  }
  
  void TreePattern::ComputeNamedNodes() {
    for (unsigned i = 0, e = Trees.size(); i != e; ++i)
      ComputeNamedNodes(Trees[i]);
  }
  
  void TreePattern::ComputeNamedNodes(TreePatternNode *N) {
    if (!N->getName().empty())
      NamedNodes[N->getName()].push_back(N);
  
    for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i)
      ComputeNamedNodes(N->getChild(i));
  }
  
  
  TreePatternNode *TreePattern::ParseTreePattern(Init *TheInit, StringRef OpName){
    if (DefInit *DI = dynamic_cast<DefInit*>(TheInit)) {
      Record *R = DI->getDef();
  
      // Direct reference to a leaf DagNode or PatFrag?  Turn it into a
      // TreePatternNode of its own.  For example:
      ///   (foo GPR, imm) -> (foo GPR, (imm))
      if (R->isSubClassOf("SDNode") || R->isSubClassOf("PatFrag"))
        return ParseTreePattern(
          DagInit::get(DI, "",
                       std::vector<std::pair<Init*, std::string> >()),
          OpName);
  
      // Input argument?
      TreePatternNode *Res = new TreePatternNode(DI, 1);
      if (R->getName() == "node" && !OpName.empty()) {
        if (OpName.empty())
          error("'node' argument requires a name to match with operand list");
        Args.push_back(OpName);
      }
  
      Res->setName(OpName);
      return Res;
    }
  
    if (IntInit *II = dynamic_cast<IntInit*>(TheInit)) {
      if (!OpName.empty())
        error("Constant int argument should not have a name!");
      return new TreePatternNode(II, 1);
    }
  
    if (BitsInit *BI = dynamic_cast<BitsInit*>(TheInit)) {
      // Turn this into an IntInit.
      Init *II = BI->convertInitializerTo(IntRecTy::get());
      if (II == 0 || !dynamic_cast<IntInit*>(II))
        error("Bits value must be constants!");
      return ParseTreePattern(II, OpName);
    }
  
    DagInit *Dag = dynamic_cast<DagInit*>(TheInit);
    if (!Dag) {
      TheInit->dump();
      error("Pattern has unexpected init kind!");
    }
    DefInit *OpDef = dynamic_cast<DefInit*>(Dag->getOperator());
    if (!OpDef) error("Pattern has unexpected operator type!");
    Record *Operator = OpDef->getDef();
  
    if (Operator->isSubClassOf("ValueType")) {
      // If the operator is a ValueType, then this must be "type cast" of a leaf
      // node.
      if (Dag->getNumArgs() != 1)
        error("Type cast only takes one operand!");
  
      TreePatternNode *New = ParseTreePattern(Dag->getArg(0), Dag->getArgName(0));
  
      // Apply the type cast.
      assert(New->getNumTypes() == 1 && "FIXME: Unhandled");
      New->UpdateNodeType(0, getValueType(Operator), *this);
  
      if (!OpName.empty())
        error("ValueType cast should not have a name!");
      return New;
    }
  
    // Verify that this is something that makes sense for an operator.
    if (!Operator->isSubClassOf("PatFrag") &&
        !Operator->isSubClassOf("SDNode") &&
        !Operator->isSubClassOf("Instruction") &&
        !Operator->isSubClassOf("SDNodeXForm") &&
        !Operator->isSubClassOf("Intrinsic") &&
        Operator->getName() != "set" &&
        Operator->getName() != "implicit")
      error("Unrecognized node '" + Operator->getName() + "'!");
  
    //  Check to see if this is something that is illegal in an input pattern.
    if (isInputPattern) {
      if (Operator->isSubClassOf("Instruction") ||
          Operator->isSubClassOf("SDNodeXForm"))
        error("Cannot use '" + Operator->getName() + "' in an input pattern!");
    } else {
      if (Operator->isSubClassOf("Intrinsic"))
        error("Cannot use '" + Operator->getName() + "' in an output pattern!");
  
      if (Operator->isSubClassOf("SDNode") &&
          Operator->getName() != "imm" &&
          Operator->getName() != "fpimm" &&
          Operator->getName() != "tglobaltlsaddr" &&
          Operator->getName() != "tconstpool" &&
          Operator->getName() != "tjumptable" &&
          Operator->getName() != "tframeindex" &&
          Operator->getName() != "texternalsym" &&
          Operator->getName() != "tblockaddress" &&
          Operator->getName() != "tglobaladdr" &&
          Operator->getName() != "bb" &&
          Operator->getName() != "vt")
        error("Cannot use '" + Operator->getName() + "' in an output pattern!");
    }
  
    std::vector<TreePatternNode*> Children;
  
    // Parse all the operands.
    for (unsigned i = 0, e = Dag->getNumArgs(); i != e; ++i)
      Children.push_back(ParseTreePattern(Dag->getArg(i), Dag->getArgName(i)));
  
    // If the operator is an intrinsic, then this is just syntactic sugar for for
    // (intrinsic_* <number>, ..children..).  Pick the right intrinsic node, and
    // convert the intrinsic name to a number.
    if (Operator->isSubClassOf("Intrinsic")) {
      const CodeGenIntrinsic &Int = getDAGPatterns().getIntrinsic(Operator);
      unsigned IID = getDAGPatterns().getIntrinsicID(Operator)+1;
  
      // If this intrinsic returns void, it must have side-effects and thus a
      // chain.
      if (Int.IS.RetVTs.empty())
        Operator = getDAGPatterns().get_intrinsic_void_sdnode();
      else if (Int.ModRef != CodeGenIntrinsic::NoMem)
        // Has side-effects, requires chain.
        Operator = getDAGPatterns().get_intrinsic_w_chain_sdnode();
      else // Otherwise, no chain.
        Operator = getDAGPatterns().get_intrinsic_wo_chain_sdnode();
  
      TreePatternNode *IIDNode = new TreePatternNode(IntInit::get(IID), 1);
      Children.insert(Children.begin(), IIDNode);
    }
  
    unsigned NumResults = GetNumNodeResults(Operator, CDP);
    TreePatternNode *Result = new TreePatternNode(Operator, Children, NumResults);
    Result->setName(OpName);
  
    if (!Dag->getName().empty()) {
      assert(Result->getName().empty());
      Result->setName(Dag->getName());
    }
    return Result;
  }
  
  /// SimplifyTree - See if we can simplify this tree to eliminate something that
  /// will never match in favor of something obvious that will.  This is here
  /// strictly as a convenience to target authors because it allows them to write
  /// more type generic things and have useless type casts fold away.
  ///
  /// This returns true if any change is made.
  static bool SimplifyTree(TreePatternNode *&N) {
    if (N->isLeaf())
      return false;
  
    // If we have a bitconvert with a resolved type and if the source and
    // destination types are the same, then the bitconvert is useless, remove it.
    if (N->getOperator()->getName() == "bitconvert" &&
        N->getExtType(0).isConcrete() &&
        N->getExtType(0) == N->getChild(0)->getExtType(0) &&
        N->getName().empty()) {
      N = N->getChild(0);
      SimplifyTree(N);
      return true;
    }
  
    // Walk all children.
    bool MadeChange = false;
    for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i) {
      TreePatternNode *Child = N->getChild(i);
      MadeChange |= SimplifyTree(Child);
      N->setChild(i, Child);
    }
    return MadeChange;
  }
  
  
  
  /// InferAllTypes - Infer/propagate as many types throughout the expression
  /// patterns as possible.  Return true if all types are inferred, false
  /// otherwise.  Throw an exception if a type contradiction is found.
  bool TreePattern::
  InferAllTypes(const StringMap<SmallVector<TreePatternNode*,1> > *InNamedTypes) {
    if (NamedNodes.empty())
      ComputeNamedNodes();
  
    bool MadeChange = true;
    while (MadeChange) {
      MadeChange = false;
      for (unsigned i = 0, e = Trees.size(); i != e; ++i) {
        MadeChange |= Trees[i]->ApplyTypeConstraints(*this, false);
        MadeChange |= SimplifyTree(Trees[i]);
      }
  
      // If there are constraints on our named nodes, apply them.
      for (StringMap<SmallVector<TreePatternNode*,1> >::iterator
           I = NamedNodes.begin(), E = NamedNodes.end(); I != E; ++I) {
        SmallVectorImpl<TreePatternNode*> &Nodes = I->second;
  
        // If we have input named node types, propagate their types to the named
        // values here.
        if (InNamedTypes) {
          // FIXME: Should be error?
          assert(InNamedTypes->count(I->getKey()) &&
                 "Named node in output pattern but not input pattern?");
  
          const SmallVectorImpl<TreePatternNode*> &InNodes =
            InNamedTypes->find(I->getKey())->second;
  
          // The input types should be fully resolved by now.
          for (unsigned i = 0, e = Nodes.size(); i != e; ++i) {
            // If this node is a register class, and it is the root of the pattern
            // then we're mapping something onto an input register.  We allow
            // changing the type of the input register in this case.  This allows
            // us to match things like:
            //  def : Pat<(v1i64 (bitconvert(v2i32 DPR:$src))), (v1i64 DPR:$src)>;
            if (Nodes[i] == Trees[0] && Nodes[i]->isLeaf()) {
              DefInit *DI = dynamic_cast<DefInit*>(Nodes[i]->getLeafValue());
              if (DI && (DI->getDef()->isSubClassOf("RegisterClass") ||
                         DI->getDef()->isSubClassOf("RegisterOperand")))
                continue;
            }
  
            assert(Nodes[i]->getNumTypes() == 1 &&
                   InNodes[0]->getNumTypes() == 1 &&
                   "FIXME: cannot name multiple result nodes yet");
            MadeChange |= Nodes[i]->UpdateNodeType(0, InNodes[0]->getExtType(0),
                                                   *this);
          }
        }
  
        // If there are multiple nodes with the same name, they must all have the
        // same type.
        if (I->second.size() > 1) {
          for (unsigned i = 0, e = Nodes.size()-1; i != e; ++i) {
            TreePatternNode *N1 = Nodes[i], *N2 = Nodes[i+1];
            assert(N1->getNumTypes() == 1 && N2->getNumTypes() == 1 &&
                   "FIXME: cannot name multiple result nodes yet");
  
            MadeChange |= N1->UpdateNodeType(0, N2->getExtType(0), *this);
            MadeChange |= N2->UpdateNodeType(0, N1->getExtType(0), *this);
          }
        }
      }
    }
  
    bool HasUnresolvedTypes = false;
    for (unsigned i = 0, e = Trees.size(); i != e; ++i)
      HasUnresolvedTypes |= Trees[i]->ContainsUnresolvedType();
    return !HasUnresolvedTypes;
  }
  
  void TreePattern::print(raw_ostream &OS) const {
    OS << getRecord()->getName();
    if (!Args.empty()) {
      OS << "(" << Args[0];
      for (unsigned i = 1, e = Args.size(); i != e; ++i)
        OS << ", " << Args[i];
      OS << ")";
    }
    OS << ": ";
  
    if (Trees.size() > 1)
      OS << "[\n";
    for (unsigned i = 0, e = Trees.size(); i != e; ++i) {
      OS << "\t";
      Trees[i]->print(OS);
      OS << "\n";
    }
  
    if (Trees.size() > 1)
      OS << "]\n";
  }
  
  void TreePattern::dump() const { print(errs()); }
  
  //===----------------------------------------------------------------------===//
  // CodeGenDAGPatterns implementation
  //
  
  CodeGenDAGPatterns::CodeGenDAGPatterns(RecordKeeper &R) :
    Records(R), Target(R) {
  
    Intrinsics = LoadIntrinsics(Records, false);
    TgtIntrinsics = LoadIntrinsics(Records, true);
    ParseNodeInfo();
    ParseNodeTransforms();
    ParseComplexPatterns();
    ParsePatternFragments();
    ParseDefaultOperands();
    ParseInstructions();
    ParsePatterns();
  
    // Generate variants.  For example, commutative patterns can match
    // multiple ways.  Add them to PatternsToMatch as well.
    GenerateVariants();
  
    // Infer instruction flags.  For example, we can detect loads,
    // stores, and side effects in many cases by examining an
    // instruction's pattern.
    InferInstructionFlags();
  }
  
  CodeGenDAGPatterns::~CodeGenDAGPatterns() {
    for (pf_iterator I = PatternFragments.begin(),
         E = PatternFragments.end(); I != E; ++I)
      delete I->second;
  }
  
  
  Record *CodeGenDAGPatterns::getSDNodeNamed(const std::string &Name) const {
    Record *N = Records.getDef(Name);
    if (!N || !N->isSubClassOf("SDNode")) {
      errs() << "Error getting SDNode '" << Name << "'!\n";
      exit(1);
    }
    return N;
  }
  
  // Parse all of the SDNode definitions for the target, populating SDNodes.
  void CodeGenDAGPatterns::ParseNodeInfo() {
    std::vector<Record*> Nodes = Records.getAllDerivedDefinitions("SDNode");
    while (!Nodes.empty()) {
      SDNodes.insert(std::make_pair(Nodes.back(), Nodes.back()));
      Nodes.pop_back();
    }
  
    // Get the builtin intrinsic nodes.
    intrinsic_void_sdnode     = getSDNodeNamed("intrinsic_void");
    intrinsic_w_chain_sdnode  = getSDNodeNamed("intrinsic_w_chain");
    intrinsic_wo_chain_sdnode = getSDNodeNamed("intrinsic_wo_chain");
  }
  
  /// ParseNodeTransforms - Parse all SDNodeXForm instances into the SDNodeXForms
  /// map, and emit them to the file as functions.
  void CodeGenDAGPatterns::ParseNodeTransforms() {
    std::vector<Record*> Xforms = Records.getAllDerivedDefinitions("SDNodeXForm");
    while (!Xforms.empty()) {
      Record *XFormNode = Xforms.back();
      Record *SDNode = XFormNode->getValueAsDef("Opcode");
      std::string Code = XFormNode->getValueAsString("XFormFunction");
      SDNodeXForms.insert(std::make_pair(XFormNode, NodeXForm(SDNode, Code)));
  
      Xforms.pop_back();
    }
  }
  
  void CodeGenDAGPatterns::ParseComplexPatterns() {
    std::vector<Record*> AMs = Records.getAllDerivedDefinitions("ComplexPattern");
    while (!AMs.empty()) {
      ComplexPatterns.insert(std::make_pair(AMs.back(), AMs.back()));
      AMs.pop_back();
    }
  }
  
  
  /// ParsePatternFragments - Parse all of the PatFrag definitions in the .td
  /// file, building up the PatternFragments map.  After we've collected them all,
  /// inline fragments together as necessary, so that there are no references left
  /// inside a pattern fragment to a pattern fragment.
  ///
  void CodeGenDAGPatterns::ParsePatternFragments() {
    std::vector<Record*> Fragments = Records.getAllDerivedDefinitions("PatFrag");
  
    // First step, parse all of the fragments.
    for (unsigned i = 0, e = Fragments.size(); i != e; ++i) {
      DagInit *Tree = Fragments[i]->getValueAsDag("Fragment");
      TreePattern *P = new TreePattern(Fragments[i], Tree, true, *this);
      PatternFragments[Fragments[i]] = P;
  
      // Validate the argument list, converting it to set, to discard duplicates.
      std::vector<std::string> &Args = P->getArgList();
      std::set<std::string> OperandsSet(Args.begin(), Args.end());
  
      if (OperandsSet.count(""))
        P->error("Cannot have unnamed 'node' values in pattern fragment!");
  
      // Parse the operands list.
      DagInit *OpsList = Fragments[i]->getValueAsDag("Operands");
      DefInit *OpsOp = dynamic_cast<DefInit*>(OpsList->getOperator());
      // Special cases: ops == outs == ins. Different names are used to
      // improve readability.
      if (!OpsOp ||
          (OpsOp->getDef()->getName() != "ops" &&
           OpsOp->getDef()->getName() != "outs" &&
           OpsOp->getDef()->getName() != "ins"))
        P->error("Operands list should start with '(ops ... '!");
  
      // Copy over the arguments.
      Args.clear();
      for (unsigned j = 0, e = OpsList->getNumArgs(); j != e; ++j) {
        if (!dynamic_cast<DefInit*>(OpsList->getArg(j)) ||
            static_cast<DefInit*>(OpsList->getArg(j))->
            getDef()->getName() != "node")
          P->error("Operands list should all be 'node' values.");
        if (OpsList->getArgName(j).empty())
          P->error("Operands list should have names for each operand!");
        if (!OperandsSet.count(OpsList->getArgName(j)))
          P->error("'" + OpsList->getArgName(j) +
                   "' does not occur in pattern or was multiply specified!");
        OperandsSet.erase(OpsList->getArgName(j));
        Args.push_back(OpsList->getArgName(j));
      }
  
      if (!OperandsSet.empty())
        P->error("Operands list does not contain an entry for operand '" +
                 *OperandsSet.begin() + "'!");
  
      // If there is a code init for this fragment, keep track of the fact that
      // this fragment uses it.
      TreePredicateFn PredFn(P);
      if (!PredFn.isAlwaysTrue())
        P->getOnlyTree()->addPredicateFn(PredFn);
  
      // If there is a node transformation corresponding to this, keep track of
      // it.
      Record *Transform = Fragments[i]->getValueAsDef("OperandTransform");
      if (!getSDNodeTransform(Transform).second.empty())    // not noop xform?
        P->getOnlyTree()->setTransformFn(Transform);
    }
  
    // Now that we've parsed all of the tree fragments, do a closure on them so
    // that there are not references to PatFrags left inside of them.
    for (unsigned i = 0, e = Fragments.size(); i != e; ++i) {
      TreePattern *ThePat = PatternFragments[Fragments[i]];
      ThePat->InlinePatternFragments();
  
      // Infer as many types as possible.  Don't worry about it if we don't infer
      // all of them, some may depend on the inputs of the pattern.
      try {
        ThePat->InferAllTypes();
      } catch (...) {
        // If this pattern fragment is not supported by this target (no types can
        // satisfy its constraints), just ignore it.  If the bogus pattern is
        // actually used by instructions, the type consistency error will be
        // reported there.
      }
  
      // If debugging, print out the pattern fragment result.
      DEBUG(ThePat->dump());
    }
  }
  
  void CodeGenDAGPatterns::ParseDefaultOperands() {
    std::vector<Record*> DefaultOps[2];
    DefaultOps[0] = Records.getAllDerivedDefinitions("PredicateOperand");
    DefaultOps[1] = Records.getAllDerivedDefinitions("OptionalDefOperand");
  
    // Find some SDNode.
    assert(!SDNodes.empty() && "No SDNodes parsed?");
    Init *SomeSDNode = DefInit::get(SDNodes.begin()->first);
  
    for (unsigned iter = 0; iter != 2; ++iter) {
      for (unsigned i = 0, e = DefaultOps[iter].size(); i != e; ++i) {
        DagInit *DefaultInfo = DefaultOps[iter][i]->getValueAsDag("DefaultOps");
  
        // Clone the DefaultInfo dag node, changing the operator from 'ops' to
        // SomeSDnode so that we can parse this.
        std::vector<std::pair<Init*, std::string> > Ops;
        for (unsigned op = 0, e = DefaultInfo->getNumArgs(); op != e; ++op)
          Ops.push_back(std::make_pair(DefaultInfo->getArg(op),
                                       DefaultInfo->getArgName(op)));
        DagInit *DI = DagInit::get(SomeSDNode, "", Ops);
  
        // Create a TreePattern to parse this.
        TreePattern P(DefaultOps[iter][i], DI, false, *this);
        assert(P.getNumTrees() == 1 && "This ctor can only produce one tree!");
  
        // Copy the operands over into a DAGDefaultOperand.
        DAGDefaultOperand DefaultOpInfo;
  
        TreePatternNode *T = P.getTree(0);
        for (unsigned op = 0, e = T->getNumChildren(); op != e; ++op) {
          TreePatternNode *TPN = T->getChild(op);
          while (TPN->ApplyTypeConstraints(P, false))
            /* Resolve all types */;
  
          if (TPN->ContainsUnresolvedType()) {
            if (iter == 0)
              throw "Value #" + utostr(i) + " of PredicateOperand '" +
                DefaultOps[iter][i]->getName() +"' doesn't have a concrete type!";
            else
              throw "Value #" + utostr(i) + " of OptionalDefOperand '" +
                DefaultOps[iter][i]->getName() +"' doesn't have a concrete type!";
          }
          DefaultOpInfo.DefaultOps.push_back(TPN);
        }
  
        // Insert it into the DefaultOperands map so we can find it later.
        DefaultOperands[DefaultOps[iter][i]] = DefaultOpInfo;
      }
    }
  }
  
  /// HandleUse - Given "Pat" a leaf in the pattern, check to see if it is an
  /// instruction input.  Return true if this is a real use.
  static bool HandleUse(TreePattern *I, TreePatternNode *Pat,
                        std::map<std::string, TreePatternNode*> &InstInputs) {
    // No name -> not interesting.
    if (Pat->getName().empty()) {
      if (Pat->isLeaf()) {
        DefInit *DI = dynamic_cast<DefInit*>(Pat->getLeafValue());
        if (DI && (DI->getDef()->isSubClassOf("RegisterClass") ||
                   DI->getDef()->isSubClassOf("RegisterOperand")))
          I->error("Input " + DI->getDef()->getName() + " must be named!");
      }
      return false;
    }
  
    Record *Rec;
    if (Pat->isLeaf()) {
      DefInit *DI = dynamic_cast<DefInit*>(Pat->getLeafValue());
      if (!DI) I->error("Input $" + Pat->getName() + " must be an identifier!");
      Rec = DI->getDef();
    } else {
      Rec = Pat->getOperator();
    }
  
    // SRCVALUE nodes are ignored.
    if (Rec->getName() == "srcvalue")
      return false;
  
    TreePatternNode *&Slot = InstInputs[Pat->getName()];
    if (!Slot) {
      Slot = Pat;
      return true;
    }
    Record *SlotRec;
    if (Slot->isLeaf()) {
      SlotRec = dynamic_cast<DefInit*>(Slot->getLeafValue())->getDef();
    } else {
      assert(Slot->getNumChildren() == 0 && "can't be a use with children!");
      SlotRec = Slot->getOperator();
    }
  
    // Ensure that the inputs agree if we've already seen this input.
    if (Rec != SlotRec)
      I->error("All $" + Pat->getName() + " inputs must agree with each other");
    if (Slot->getExtTypes() != Pat->getExtTypes())
      I->error("All $" + Pat->getName() + " inputs must agree with each other");
    return true;
  }
  
  /// FindPatternInputsAndOutputs - Scan the specified TreePatternNode (which is
  /// part of "I", the instruction), computing the set of inputs and outputs of
  /// the pattern.  Report errors if we see anything naughty.
  void CodeGenDAGPatterns::
  FindPatternInputsAndOutputs(TreePattern *I, TreePatternNode *Pat,
                              std::map<std::string, TreePatternNode*> &InstInputs,
                              std::map<std::string, TreePatternNode*>&InstResults,
                              std::vector<Record*> &InstImpResults) {
    if (Pat->isLeaf()) {
      bool isUse = HandleUse(I, Pat, InstInputs);
      if (!isUse && Pat->getTransformFn())
        I->error("Cannot specify a transform function for a non-input value!");
      return;
    }
  
    if (Pat->getOperator()->getName() == "implicit") {
      for (unsigned i = 0, e = Pat->getNumChildren(); i != e; ++i) {
        TreePatternNode *Dest = Pat->getChild(i);
        if (!Dest->isLeaf())
          I->error("implicitly defined value should be a register!");
  
        DefInit *Val = dynamic_cast<DefInit*>(Dest->getLeafValue());
        if (!Val || !Val->getDef()->isSubClassOf("Register"))
          I->error("implicitly defined value should be a register!");
        InstImpResults.push_back(Val->getDef());
      }
      return;
    }
  
    if (Pat->getOperator()->getName() != "set") {
      // If this is not a set, verify that the children nodes are not void typed,
      // and recurse.
      for (unsigned i = 0, e = Pat->getNumChildren(); i != e; ++i) {
        if (Pat->getChild(i)->getNumTypes() == 0)
          I->error("Cannot have void nodes inside of patterns!");
        FindPatternInputsAndOutputs(I, Pat->getChild(i), InstInputs, InstResults,
                                    InstImpResults);
      }
  
      // If this is a non-leaf node with no children, treat it basically as if
      // it were a leaf.  This handles nodes like (imm).
      bool isUse = HandleUse(I, Pat, InstInputs);
  
      if (!isUse && Pat->getTransformFn())
        I->error("Cannot specify a transform function for a non-input value!");
      return;
    }
  
    // Otherwise, this is a set, validate and collect instruction results.
    if (Pat->getNumChildren() == 0)
      I->error("set requires operands!");
  
    if (Pat->getTransformFn())
      I->error("Cannot specify a transform function on a set node!");
  
    // Check the set destinations.
    unsigned NumDests = Pat->getNumChildren()-1;
    for (unsigned i = 0; i != NumDests; ++i) {
      TreePatternNode *Dest = Pat->getChild(i);
      if (!Dest->isLeaf())
        I->error("set destination should be a register!");
  
      DefInit *Val = dynamic_cast<DefInit*>(Dest->getLeafValue());
      if (!Val)
        I->error("set destination should be a register!");
  
      if (Val->getDef()->isSubClassOf("RegisterClass") ||
          Val->getDef()->isSubClassOf("RegisterOperand") ||
          Val->getDef()->isSubClassOf("PointerLikeRegClass")) {
        if (Dest->getName().empty())
          I->error("set destination must have a name!");
        if (InstResults.count(Dest->getName()))
          I->error("cannot set '" + Dest->getName() +"' multiple times");
        InstResults[Dest->getName()] = Dest;
      } else if (Val->getDef()->isSubClassOf("Register")) {
        InstImpResults.push_back(Val->getDef());
      } else {
        I->error("set destination should be a register!");
      }
    }
  
    // Verify and collect info from the computation.
    FindPatternInputsAndOutputs(I, Pat->getChild(NumDests),
                                InstInputs, InstResults, InstImpResults);
  }
  
  //===----------------------------------------------------------------------===//
  // Instruction Analysis
  //===----------------------------------------------------------------------===//
  
  class InstAnalyzer {
    const CodeGenDAGPatterns &CDP;
    bool &mayStore;
    bool &mayLoad;
    bool &IsBitcast;
    bool &HasSideEffects;
    bool &IsVariadic;
  public:
    InstAnalyzer(const CodeGenDAGPatterns &cdp,
                 bool &maystore, bool &mayload, bool &isbc, bool &hse, bool &isv)
      : CDP(cdp), mayStore(maystore), mayLoad(mayload), IsBitcast(isbc),
        HasSideEffects(hse), IsVariadic(isv) {
    }
  
    /// Analyze - Analyze the specified instruction, returning true if the
    /// instruction had a pattern.
    bool Analyze(Record *InstRecord) {
      const TreePattern *Pattern = CDP.getInstruction(InstRecord).getPattern();
      if (Pattern == 0) {
        HasSideEffects = 1;
        return false;  // No pattern.
      }
  
      // FIXME: Assume only the first tree is the pattern. The others are clobber
      // nodes.
      AnalyzeNode(Pattern->getTree(0));
      return true;
    }
  
  private:
    bool IsNodeBitcast(const TreePatternNode *N) const {
      if (HasSideEffects || mayLoad || mayStore || IsVariadic)
        return false;
  
      if (N->getNumChildren() != 2)
        return false;
  
      const TreePatternNode *N0 = N->getChild(0);
      if (!N0->isLeaf() || !dynamic_cast<DefInit*>(N0->getLeafValue()))
        return false;
  
      const TreePatternNode *N1 = N->getChild(1);
      if (N1->isLeaf())
        return false;
      if (N1->getNumChildren() != 1 || !N1->getChild(0)->isLeaf())
        return false;
  
      const SDNodeInfo &OpInfo = CDP.getSDNodeInfo(N1->getOperator());
      if (OpInfo.getNumResults() != 1 || OpInfo.getNumOperands() != 1)
        return false;
      return OpInfo.getEnumName() == "ISD::BITCAST";
    }
  
    void AnalyzeNode(const TreePatternNode *N) {
      if (N->isLeaf()) {
        if (DefInit *DI = dynamic_cast<DefInit*>(N->getLeafValue())) {
          Record *LeafRec = DI->getDef();
          // Handle ComplexPattern leaves.
          if (LeafRec->isSubClassOf("ComplexPattern")) {
            const ComplexPattern &CP = CDP.getComplexPattern(LeafRec);
            if (CP.hasProperty(SDNPMayStore)) mayStore = true;
            if (CP.hasProperty(SDNPMayLoad)) mayLoad = true;
            if (CP.hasProperty(SDNPSideEffect)) HasSideEffects = true;
          }
        }
        return;
      }
  
      // Analyze children.
      for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i)
        AnalyzeNode(N->getChild(i));
  
      // Ignore set nodes, which are not SDNodes.
      if (N->getOperator()->getName() == "set") {
        IsBitcast = IsNodeBitcast(N);
        return;
      }
  
      // Get information about the SDNode for the operator.
      const SDNodeInfo &OpInfo = CDP.getSDNodeInfo(N->getOperator());
  
      // Notice properties of the node.
      if (OpInfo.hasProperty(SDNPMayStore)) mayStore = true;
      if (OpInfo.hasProperty(SDNPMayLoad)) mayLoad = true;
      if (OpInfo.hasProperty(SDNPSideEffect)) HasSideEffects = true;
      if (OpInfo.hasProperty(SDNPVariadic)) IsVariadic = true;
  
      if (const CodeGenIntrinsic *IntInfo = N->getIntrinsicInfo(CDP)) {
        // If this is an intrinsic, analyze it.
        if (IntInfo->ModRef >= CodeGenIntrinsic::ReadArgMem)
          mayLoad = true;// These may load memory.
  
        if (IntInfo->ModRef >= CodeGenIntrinsic::ReadWriteArgMem)
          mayStore = true;// Intrinsics that can write to memory are 'mayStore'.
  
        if (IntInfo->ModRef >= CodeGenIntrinsic::ReadWriteMem)
          // WriteMem intrinsics can have other strange effects.
          HasSideEffects = true;
      }
    }
  
  };
  
  static void InferFromPattern(const CodeGenInstruction &Inst,
                               bool &MayStore, bool &MayLoad,
                               bool &IsBitcast,
                               bool &HasSideEffects, bool &IsVariadic,
                               const CodeGenDAGPatterns &CDP) {
    MayStore = MayLoad = IsBitcast = HasSideEffects = IsVariadic = false;
  
    bool HadPattern =
      InstAnalyzer(CDP, MayStore, MayLoad, IsBitcast, HasSideEffects, IsVariadic)
      .Analyze(Inst.TheDef);
  
    // InstAnalyzer only correctly analyzes mayStore/mayLoad so far.
    if (Inst.mayStore) {  // If the .td file explicitly sets mayStore, use it.
      // If we decided that this is a store from the pattern, then the .td file
      // entry is redundant.
      if (MayStore)
        PrintWarning(Inst.TheDef->getLoc(),
                     "mayStore flag explicitly set on "
                     "instruction, but flag already inferred from pattern.");
      MayStore = true;
    }
  
    if (Inst.mayLoad) {  // If the .td file explicitly sets mayLoad, use it.
      // If we decided that this is a load from the pattern, then the .td file
      // entry is redundant.
      if (MayLoad)
        PrintWarning(Inst.TheDef->getLoc(),
                     "mayLoad flag explicitly set on "
                     "instruction, but flag already inferred from pattern.");
      MayLoad = true;
    }
  
    if (Inst.neverHasSideEffects) {
      if (HadPattern)
        PrintWarning(Inst.TheDef->getLoc(),
                     "neverHasSideEffects flag explicitly set on "
                     "instruction, but flag already inferred from pattern.");
      HasSideEffects = false;
    }
  
    if (Inst.hasSideEffects) {
      if (HasSideEffects)
        PrintWarning(Inst.TheDef->getLoc(),
                     "hasSideEffects flag explicitly set on "
                     "instruction, but flag already inferred from pattern.");
      HasSideEffects = true;
    }
  
    if (Inst.Operands.isVariadic)
      IsVariadic = true;  // Can warn if we want.
  }
  
  /// ParseInstructions - Parse all of the instructions, inlining and resolving
  /// any fragments involved.  This populates the Instructions list with fully
  /// resolved instructions.
  void CodeGenDAGPatterns::ParseInstructions() {
    std::vector<Record*> Instrs = Records.getAllDerivedDefinitions("Instruction");
  
    for (unsigned i = 0, e = Instrs.size(); i != e; ++i) {
      ListInit *LI = 0;
  
      if (dynamic_cast<ListInit*>(Instrs[i]->getValueInit("Pattern")))
        LI = Instrs[i]->getValueAsListInit("Pattern");
  
      // If there is no pattern, only collect minimal information about the
      // instruction for its operand list.  We have to assume that there is one
      // result, as we have no detailed info.
      if (!LI || LI->getSize() == 0) {
        std::vector<Record*> Results;
        std::vector<Record*> Operands;
  
        CodeGenInstruction &InstInfo = Target.getInstruction(Instrs[i]);
  
        if (InstInfo.Operands.size() != 0) {
          if (InstInfo.Operands.NumDefs == 0) {
            // These produce no results
            for (unsigned j = 0, e = InstInfo.Operands.size(); j < e; ++j)
              Operands.push_back(InstInfo.Operands[j].Rec);
          } else {
            // Assume the first operand is the result.
            Results.push_back(InstInfo.Operands[0].Rec);
  
            // The rest are inputs.
            for (unsigned j = 1, e = InstInfo.Operands.size(); j < e; ++j)
              Operands.push_back(InstInfo.Operands[j].Rec);
          }
        }
  
        // Create and insert the instruction.
        std::vector<Record*> ImpResults;
        Instructions.insert(std::make_pair(Instrs[i],
                            DAGInstruction(0, Results, Operands, ImpResults)));
        continue;  // no pattern.
      }
  
      // Parse the instruction.
      TreePattern *I = new TreePattern(Instrs[i], LI, true, *this);
      // Inline pattern fragments into it.
      I->InlinePatternFragments();
  
      // Infer as many types as possible.  If we cannot infer all of them, we can
      // never do anything with this instruction pattern: report it to the user.
      if (!I->InferAllTypes())
        I->error("Could not infer all types in pattern!");
  
      // InstInputs - Keep track of all of the inputs of the instruction, along
      // with the record they are declared as.
      std::map<std::string, TreePatternNode*> InstInputs;
  
      // InstResults - Keep track of all the virtual registers that are 'set'
      // in the instruction, including what reg class they are.
      std::map<std::string, TreePatternNode*> InstResults;
  
      std::vector<Record*> InstImpResults;
  
      // Verify that the top-level forms in the instruction are of void type, and
      // fill in the InstResults map.
      for (unsigned j = 0, e = I->getNumTrees(); j != e; ++j) {
        TreePatternNode *Pat = I->getTree(j);
        if (Pat->getNumTypes() != 0)
          I->error("Top-level forms in instruction pattern should have"
                   " void types");
  
        // Find inputs and outputs, and verify the structure of the uses/defs.
        FindPatternInputsAndOutputs(I, Pat, InstInputs, InstResults,
                                    InstImpResults);
      }
  
      // Now that we have inputs and outputs of the pattern, inspect the operands
      // list for the instruction.  This determines the order that operands are
      // added to the machine instruction the node corresponds to.
      unsigned NumResults = InstResults.size();
  
      // Parse the operands list from the (ops) list, validating it.
      assert(I->getArgList().empty() && "Args list should still be empty here!");
      CodeGenInstruction &CGI = Target.getInstruction(Instrs[i]);
  
      // Check that all of the results occur first in the list.
      std::vector<Record*> Results;
      TreePatternNode *Res0Node = 0;
      for (unsigned i = 0; i != NumResults; ++i) {
        if (i == CGI.Operands.size())
          I->error("'" + InstResults.begin()->first +
                   "' set but does not appear in operand list!");
        const std::string &OpName = CGI.Operands[i].Name;
  
        // Check that it exists in InstResults.
        TreePatternNode *RNode = InstResults[OpName];
        if (RNode == 0)
          I->error("Operand $" + OpName + " does not exist in operand list!");
  
        if (i == 0)
          Res0Node = RNode;
        Record *R = dynamic_cast<DefInit*>(RNode->getLeafValue())->getDef();
        if (R == 0)
          I->error("Operand $" + OpName + " should be a set destination: all "
                   "outputs must occur before inputs in operand list!");
  
        if (CGI.Operands[i].Rec != R)
          I->error("Operand $" + OpName + " class mismatch!");
  
        // Remember the return type.
        Results.push_back(CGI.Operands[i].Rec);
  
        // Okay, this one checks out.
        InstResults.erase(OpName);
      }
  
      // Loop over the inputs next.  Make a copy of InstInputs so we can destroy
      // the copy while we're checking the inputs.
      std::map<std::string, TreePatternNode*> InstInputsCheck(InstInputs);
  
      std::vector<TreePatternNode*> ResultNodeOperands;
      std::vector<Record*> Operands;
      for (unsigned i = NumResults, e = CGI.Operands.size(); i != e; ++i) {
        CGIOperandList::OperandInfo &Op = CGI.Operands[i];
        const std::string &OpName = Op.Name;
        if (OpName.empty())
          I->error("Operand #" + utostr(i) + " in operands list has no name!");
  
        if (!InstInputsCheck.count(OpName)) {
          // If this is an predicate operand or optional def operand with an
          // DefaultOps set filled in, we can ignore this.  When we codegen it,
          // we will do so as always executed.
          if (Op.Rec->isSubClassOf("PredicateOperand") ||
              Op.Rec->isSubClassOf("OptionalDefOperand")) {
            // Does it have a non-empty DefaultOps field?  If so, ignore this
            // operand.
            if (!getDefaultOperand(Op.Rec).DefaultOps.empty())
              continue;
          }
          I->error("Operand $" + OpName +
                   " does not appear in the instruction pattern");
        }
        TreePatternNode *InVal = InstInputsCheck[OpName];
        InstInputsCheck.erase(OpName);   // It occurred, remove from map.
  
        if (InVal->isLeaf() &&
            dynamic_cast<DefInit*>(InVal->getLeafValue())) {
          Record *InRec = static_cast<DefInit*>(InVal->getLeafValue())->getDef();
          if (Op.Rec != InRec && !InRec->isSubClassOf("ComplexPattern"))
            I->error("Operand $" + OpName + "'s register class disagrees"
                     " between the operand and pattern");
        }
        Operands.push_back(Op.Rec);
  
        // Construct the result for the dest-pattern operand list.
        TreePatternNode *OpNode = InVal->clone();
  
        // No predicate is useful on the result.
        OpNode->clearPredicateFns();
  
        // Promote the xform function to be an explicit node if set.
        if (Record *Xform = OpNode->getTransformFn()) {
          OpNode->setTransformFn(0);
          std::vector<TreePatternNode*> Children;
          Children.push_back(OpNode);
          OpNode = new TreePatternNode(Xform, Children, OpNode->getNumTypes());
        }
  
        ResultNodeOperands.push_back(OpNode);
      }
  
      if (!InstInputsCheck.empty())
        I->error("Input operand $" + InstInputsCheck.begin()->first +
                 " occurs in pattern but not in operands list!");
  
      TreePatternNode *ResultPattern =
        new TreePatternNode(I->getRecord(), ResultNodeOperands,
                            GetNumNodeResults(I->getRecord(), *this));
      // Copy fully inferred output node type to instruction result pattern.
      for (unsigned i = 0; i != NumResults; ++i)
        ResultPattern->setType(i, Res0Node->getExtType(i));
  
      // Create and insert the instruction.
      // FIXME: InstImpResults should not be part of DAGInstruction.
      DAGInstruction TheInst(I, Results, Operands, InstImpResults);
      Instructions.insert(std::make_pair(I->getRecord(), TheInst));
  
      // Use a temporary tree pattern to infer all types and make sure that the
      // constructed result is correct.  This depends on the instruction already
      // being inserted into the Instructions map.
      TreePattern Temp(I->getRecord(), ResultPattern, false, *this);
      Temp.InferAllTypes(&I->getNamedNodesMap());
  
      DAGInstruction &TheInsertedInst = Instructions.find(I->getRecord())->second;
      TheInsertedInst.setResultPattern(Temp.getOnlyTree());
  
      DEBUG(I->dump());
    }
  
    // If we can, convert the instructions to be patterns that are matched!
    for (std::map<Record*, DAGInstruction, RecordPtrCmp>::iterator II =
          Instructions.begin(),
         E = Instructions.end(); II != E; ++II) {
      DAGInstruction &TheInst = II->second;
      const TreePattern *I = TheInst.getPattern();
      if (I == 0) continue;  // No pattern.
  
      // FIXME: Assume only the first tree is the pattern. The others are clobber
      // nodes.
      TreePatternNode *Pattern = I->getTree(0);
      TreePatternNode *SrcPattern;
      if (Pattern->getOperator()->getName() == "set") {
        SrcPattern = Pattern->getChild(Pattern->getNumChildren()-1)->clone();
      } else{
        // Not a set (store or something?)
        SrcPattern = Pattern;
      }
  
      Record *Instr = II->first;
      AddPatternToMatch(I,
                        PatternToMatch(Instr,
                                       Instr->getValueAsListInit("Predicates"),
                                       SrcPattern,
                                       TheInst.getResultPattern(),
                                       TheInst.getImpResults(),
                                       Instr->getValueAsInt("AddedComplexity"),
                                       Instr->getID()));
    }
  }
  
  
  typedef std::pair<const TreePatternNode*, unsigned> NameRecord;
  
  static void FindNames(const TreePatternNode *P,
                        std::map<std::string, NameRecord> &Names,
                        const TreePattern *PatternTop) {
    if (!P->getName().empty()) {
      NameRecord &Rec = Names[P->getName()];
      // If this is the first instance of the name, remember the node.
      if (Rec.second++ == 0)
        Rec.first = P;
      else if (Rec.first->getExtTypes() != P->getExtTypes())
        PatternTop->error("repetition of value: $" + P->getName() +
                          " where different uses have different types!");
    }
  
    if (!P->isLeaf()) {
      for (unsigned i = 0, e = P->getNumChildren(); i != e; ++i)
        FindNames(P->getChild(i), Names, PatternTop);
    }
  }
  
  void CodeGenDAGPatterns::AddPatternToMatch(const TreePattern *Pattern,
                                             const PatternToMatch &PTM) {
    // Do some sanity checking on the pattern we're about to match.
    std::string Reason;
    if (!PTM.getSrcPattern()->canPatternMatch(Reason, *this))
      Pattern->error("Pattern can never match: " + Reason);
  
    // If the source pattern's root is a complex pattern, that complex pattern
    // must specify the nodes it can potentially match.
    if (const ComplexPattern *CP =
          PTM.getSrcPattern()->getComplexPatternInfo(*this))
      if (CP->getRootNodes().empty())
        Pattern->error("ComplexPattern at root must specify list of opcodes it"
                       " could match");
  
  
    // Find all of the named values in the input and output, ensure they have the
    // same type.
    std::map<std::string, NameRecord> SrcNames, DstNames;
    FindNames(PTM.getSrcPattern(), SrcNames, Pattern);
    FindNames(PTM.getDstPattern(), DstNames, Pattern);
  
    // Scan all of the named values in the destination pattern, rejecting them if
    // they don't exist in the input pattern.
    for (std::map<std::string, NameRecord>::iterator
         I = DstNames.begin(), E = DstNames.end(); I != E; ++I) {
      if (SrcNames[I->first].first == 0)
        Pattern->error("Pattern has input without matching name in output: $" +
                       I->first);
    }
  
    // Scan all of the named values in the source pattern, rejecting them if the
    // name isn't used in the dest, and isn't used to tie two values together.
    for (std::map<std::string, NameRecord>::iterator
         I = SrcNames.begin(), E = SrcNames.end(); I != E; ++I)
      if (DstNames[I->first].first == 0 && SrcNames[I->first].second == 1)
        Pattern->error("Pattern has dead named input: $" + I->first);
  
    PatternsToMatch.push_back(PTM);
  }
  
  
  
  void CodeGenDAGPatterns::InferInstructionFlags() {
    const std::vector<const CodeGenInstruction*> &Instructions =
      Target.getInstructionsByEnumValue();
    for (unsigned i = 0, e = Instructions.size(); i != e; ++i) {
      CodeGenInstruction &InstInfo =
        const_cast<CodeGenInstruction &>(*Instructions[i]);
      // Determine properties of the instruction from its pattern.
      bool MayStore, MayLoad, IsBitcast, HasSideEffects, IsVariadic;
      InferFromPattern(InstInfo, MayStore, MayLoad, IsBitcast,
                       HasSideEffects, IsVariadic, *this);
      InstInfo.mayStore = MayStore;
      InstInfo.mayLoad = MayLoad;
      InstInfo.isBitcast = IsBitcast;
      InstInfo.hasSideEffects = HasSideEffects;
      InstInfo.Operands.isVariadic = IsVariadic;
  
      // Sanity checks.
      if (InstInfo.isReMaterializable && InstInfo.hasSideEffects)
        throw TGError(InstInfo.TheDef->getLoc(), "The instruction " +
                      InstInfo.TheDef->getName() +
                      " is rematerializable AND has unmodeled side effects?");
    }
  }
  
  /// Given a pattern result with an unresolved type, see if we can find one
  /// instruction with an unresolved result type.  Force this result type to an
  /// arbitrary element if it's possible types to converge results.
  static bool ForceArbitraryInstResultType(TreePatternNode *N, TreePattern &TP) {
    if (N->isLeaf())
      return false;
  
    // Analyze children.
    for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i)
      if (ForceArbitraryInstResultType(N->getChild(i), TP))
        return true;
  
    if (!N->getOperator()->isSubClassOf("Instruction"))
      return false;
  
    // If this type is already concrete or completely unknown we can't do
    // anything.
    for (unsigned i = 0, e = N->getNumTypes(); i != e; ++i) {
      if (N->getExtType(i).isCompletelyUnknown() || N->getExtType(i).isConcrete())
        continue;
  
      // Otherwise, force its type to the first possibility (an arbitrary choice).
      if (N->getExtType(i).MergeInTypeInfo(N->getExtType(i).getTypeList()[0], TP))
        return true;
    }
  
    return false;
  }
  
  void CodeGenDAGPatterns::ParsePatterns() {
    std::vector<Record*> Patterns = Records.getAllDerivedDefinitions("Pattern");
  
    for (unsigned i = 0, e = Patterns.size(); i != e; ++i) {
      Record *CurPattern = Patterns[i];
      DagInit *Tree = CurPattern->getValueAsDag("PatternToMatch");
      TreePattern *Pattern = new TreePattern(CurPattern, Tree, true, *this);
  
      // Inline pattern fragments into it.
      Pattern->InlinePatternFragments();
  
      ListInit *LI = CurPattern->getValueAsListInit("ResultInstrs");
      if (LI->getSize() == 0) continue;  // no pattern.
  
      // Parse the instruction.
      TreePattern *Result = new TreePattern(CurPattern, LI, false, *this);
  
      // Inline pattern fragments into it.
      Result->InlinePatternFragments();
  
      if (Result->getNumTrees() != 1)
        Result->error("Cannot handle instructions producing instructions "
                      "with temporaries yet!");
  
      bool IterateInference;
      bool InferredAllPatternTypes, InferredAllResultTypes;
      do {
        // Infer as many types as possible.  If we cannot infer all of them, we
        // can never do anything with this pattern: report it to the user.
        InferredAllPatternTypes =
          Pattern->InferAllTypes(&Pattern->getNamedNodesMap());
  
        // Infer as many types as possible.  If we cannot infer all of them, we
        // can never do anything with this pattern: report it to the user.
        InferredAllResultTypes =
          Result->InferAllTypes(&Pattern->getNamedNodesMap());
  
        IterateInference = false;
  
        // Apply the type of the result to the source pattern.  This helps us
        // resolve cases where the input type is known to be a pointer type (which
        // is considered resolved), but the result knows it needs to be 32- or
        // 64-bits.  Infer the other way for good measure.
        for (unsigned i = 0, e = std::min(Result->getTree(0)->getNumTypes(),
                                          Pattern->getTree(0)->getNumTypes());
             i != e; ++i) {
          IterateInference = Pattern->getTree(0)->
            UpdateNodeType(i, Result->getTree(0)->getExtType(i), *Result);
          IterateInference |= Result->getTree(0)->
            UpdateNodeType(i, Pattern->getTree(0)->getExtType(i), *Result);
        }
  
        // If our iteration has converged and the input pattern's types are fully
        // resolved but the result pattern is not fully resolved, we may have a
        // situation where we have two instructions in the result pattern and
        // the instructions require a common register class, but don't care about
        // what actual MVT is used.  This is actually a bug in our modelling:
        // output patterns should have register classes, not MVTs.
        //
        // In any case, to handle this, we just go through and disambiguate some
        // arbitrary types to the result pattern's nodes.
        if (!IterateInference && InferredAllPatternTypes &&
            !InferredAllResultTypes)
          IterateInference = ForceArbitraryInstResultType(Result->getTree(0),
                                                          *Result);
      } while (IterateInference);
  
      // Verify that we inferred enough types that we can do something with the
      // pattern and result.  If these fire the user has to add type casts.
      if (!InferredAllPatternTypes)
        Pattern->error("Could not infer all types in pattern!");
      if (!InferredAllResultTypes) {
        Pattern->dump();
        Result->error("Could not infer all types in pattern result!");
      }
  
      // Validate that the input pattern is correct.
      std::map<std::string, TreePatternNode*> InstInputs;
      std::map<std::string, TreePatternNode*> InstResults;
      std::vector<Record*> InstImpResults;
      for (unsigned j = 0, ee = Pattern->getNumTrees(); j != ee; ++j)
        FindPatternInputsAndOutputs(Pattern, Pattern->getTree(j),
                                    InstInputs, InstResults,
                                    InstImpResults);
  
      // Promote the xform function to be an explicit node if set.
      TreePatternNode *DstPattern = Result->getOnlyTree();
      std::vector<TreePatternNode*> ResultNodeOperands;
      for (unsigned ii = 0, ee = DstPattern->getNumChildren(); ii != ee; ++ii) {
        TreePatternNode *OpNode = DstPattern->getChild(ii);
        if (Record *Xform = OpNode->getTransformFn()) {
          OpNode->setTransformFn(0);
          std::vector<TreePatternNode*> Children;
          Children.push_back(OpNode);
          OpNode = new TreePatternNode(Xform, Children, OpNode->getNumTypes());
        }
        ResultNodeOperands.push_back(OpNode);
      }
      DstPattern = Result->getOnlyTree();
      if (!DstPattern->isLeaf())
        DstPattern = new TreePatternNode(DstPattern->getOperator(),
                                         ResultNodeOperands,
                                         DstPattern->getNumTypes());
  
      for (unsigned i = 0, e = Result->getOnlyTree()->getNumTypes(); i != e; ++i)
        DstPattern->setType(i, Result->getOnlyTree()->getExtType(i));
  
      TreePattern Temp(Result->getRecord(), DstPattern, false, *this);
      Temp.InferAllTypes();
  
  
      AddPatternToMatch(Pattern,
                      PatternToMatch(CurPattern,
                                     CurPattern->getValueAsListInit("Predicates"),
                                     Pattern->getTree(0),
                                     Temp.getOnlyTree(), InstImpResults,
                                     CurPattern->getValueAsInt("AddedComplexity"),
                                     CurPattern->getID()));
    }
  }
  
  /// CombineChildVariants - Given a bunch of permutations of each child of the
  /// 'operator' node, put them together in all possible ways.
  static void CombineChildVariants(TreePatternNode *Orig,
                 const std::vector<std::vector<TreePatternNode*> > &ChildVariants,
                                   std::vector<TreePatternNode*> &OutVariants,
                                   CodeGenDAGPatterns &CDP,
                                   const MultipleUseVarSet &DepVars) {
    // Make sure that each operand has at least one variant to choose from.
    for (unsigned i = 0, e = ChildVariants.size(); i != e; ++i)
      if (ChildVariants[i].empty())
        return;
  
    // The end result is an all-pairs construction of the resultant pattern.
    std::vector<unsigned> Idxs;
    Idxs.resize(ChildVariants.size());
    bool NotDone;
    do {
  #ifndef NDEBUG
      DEBUG(if (!Idxs.empty()) {
              errs() << Orig->getOperator()->getName() << ": Idxs = [ ";
                for (unsigned i = 0; i < Idxs.size(); ++i) {
                  errs() << Idxs[i] << " ";
              }
              errs() << "]\n";
            });
  #endif
      // Create the variant and add it to the output list.
      std::vector<TreePatternNode*> NewChildren;
      for (unsigned i = 0, e = ChildVariants.size(); i != e; ++i)
        NewChildren.push_back(ChildVariants[i][Idxs[i]]);
      TreePatternNode *R = new TreePatternNode(Orig->getOperator(), NewChildren,
                                               Orig->getNumTypes());
  
      // Copy over properties.
      R->setName(Orig->getName());
      R->setPredicateFns(Orig->getPredicateFns());
      R->setTransformFn(Orig->getTransformFn());
      for (unsigned i = 0, e = Orig->getNumTypes(); i != e; ++i)
        R->setType(i, Orig->getExtType(i));
  
      // If this pattern cannot match, do not include it as a variant.
      std::string ErrString;
      if (!R->canPatternMatch(ErrString, CDP)) {
        delete R;
      } else {
        bool AlreadyExists = false;
  
        // Scan to see if this pattern has already been emitted.  We can get
        // duplication due to things like commuting:
        //   (and GPRC:$a, GPRC:$b) -> (and GPRC:$b, GPRC:$a)
        // which are the same pattern.  Ignore the dups.
        for (unsigned i = 0, e = OutVariants.size(); i != e; ++i)
          if (R->isIsomorphicTo(OutVariants[i], DepVars)) {
            AlreadyExists = true;
            break;
          }
  
        if (AlreadyExists)
          delete R;
        else
          OutVariants.push_back(R);
      }
  
      // Increment indices to the next permutation by incrementing the
      // indicies from last index backward, e.g., generate the sequence
      // [0, 0], [0, 1], [1, 0], [1, 1].
      int IdxsIdx;
      for (IdxsIdx = Idxs.size() - 1; IdxsIdx >= 0; --IdxsIdx) {
        if (++Idxs[IdxsIdx] == ChildVariants[IdxsIdx].size())
          Idxs[IdxsIdx] = 0;
        else
          break;
      }
      NotDone = (IdxsIdx >= 0);
    } while (NotDone);
  }
  
  /// CombineChildVariants - A helper function for binary operators.
  ///
  static void CombineChildVariants(TreePatternNode *Orig,
                                   const std::vector<TreePatternNode*> &LHS,
                                   const std::vector<TreePatternNode*> &RHS,
                                   std::vector<TreePatternNode*> &OutVariants,
                                   CodeGenDAGPatterns &CDP,
                                   const MultipleUseVarSet &DepVars) {
    std::vector<std::vector<TreePatternNode*> > ChildVariants;
    ChildVariants.push_back(LHS);
    ChildVariants.push_back(RHS);
    CombineChildVariants(Orig, ChildVariants, OutVariants, CDP, DepVars);
  }
  
  
  static void GatherChildrenOfAssociativeOpcode(TreePatternNode *N,
                                       std::vector<TreePatternNode *> &Children) {
    assert(N->getNumChildren()==2 &&"Associative but doesn't have 2 children!");
    Record *Operator = N->getOperator();
  
    // Only permit raw nodes.
    if (!N->getName().empty() || !N->getPredicateFns().empty() ||
        N->getTransformFn()) {
      Children.push_back(N);
      return;
    }
  
    if (N->getChild(0)->isLeaf() || N->getChild(0)->getOperator() != Operator)
      Children.push_back(N->getChild(0));
    else
      GatherChildrenOfAssociativeOpcode(N->getChild(0), Children);
  
    if (N->getChild(1)->isLeaf() || N->getChild(1)->getOperator() != Operator)
      Children.push_back(N->getChild(1));
    else
      GatherChildrenOfAssociativeOpcode(N->getChild(1), Children);
  }
  
  /// GenerateVariantsOf - Given a pattern N, generate all permutations we can of
  /// the (potentially recursive) pattern by using algebraic laws.
  ///
  static void GenerateVariantsOf(TreePatternNode *N,
                                 std::vector<TreePatternNode*> &OutVariants,
                                 CodeGenDAGPatterns &CDP,
                                 const MultipleUseVarSet &DepVars) {
    // We cannot permute leaves.
    if (N->isLeaf()) {
      OutVariants.push_back(N);
      return;
    }
  
    // Look up interesting info about the node.
    const SDNodeInfo &NodeInfo = CDP.getSDNodeInfo(N->getOperator());
  
    // If this node is associative, re-associate.
    if (NodeInfo.hasProperty(SDNPAssociative)) {
      // Re-associate by pulling together all of the linked operators
      std::vector<TreePatternNode*> MaximalChildren;
      GatherChildrenOfAssociativeOpcode(N, MaximalChildren);
  
      // Only handle child sizes of 3.  Otherwise we'll end up trying too many
      // permutations.
      if (MaximalChildren.size() == 3) {
        // Find the variants of all of our maximal children.
        std::vector<TreePatternNode*> AVariants, BVariants, CVariants;
        GenerateVariantsOf(MaximalChildren[0], AVariants, CDP, DepVars);
        GenerateVariantsOf(MaximalChildren[1], BVariants, CDP, DepVars);
        GenerateVariantsOf(MaximalChildren[2], CVariants, CDP, DepVars);
  
        // There are only two ways we can permute the tree:
        //   (A op B) op C    and    A op (B op C)
        // Within these forms, we can also permute A/B/C.
  
        // Generate legal pair permutations of A/B/C.
        std::vector<TreePatternNode*> ABVariants;
        std::vector<TreePatternNode*> BAVariants;
        std::vector<TreePatternNode*> ACVariants;
        std::vector<TreePatternNode*> CAVariants;
        std::vector<TreePatternNode*> BCVariants;
        std::vector<TreePatternNode*> CBVariants;
        CombineChildVariants(N, AVariants, BVariants, ABVariants, CDP, DepVars);
        CombineChildVariants(N, BVariants, AVariants, BAVariants, CDP, DepVars);
        CombineChildVariants(N, AVariants, CVariants, ACVariants, CDP, DepVars);
        CombineChildVariants(N, CVariants, AVariants, CAVariants, CDP, DepVars);
        CombineChildVariants(N, BVariants, CVariants, BCVariants, CDP, DepVars);
        CombineChildVariants(N, CVariants, BVariants, CBVariants, CDP, DepVars);
  
        // Combine those into the result: (x op x) op x
        CombineChildVariants(N, ABVariants, CVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, BAVariants, CVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, ACVariants, BVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, CAVariants, BVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, BCVariants, AVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, CBVariants, AVariants, OutVariants, CDP, DepVars);
  
        // Combine those into the result: x op (x op x)
        CombineChildVariants(N, CVariants, ABVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, CVariants, BAVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, BVariants, ACVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, BVariants, CAVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, AVariants, BCVariants, OutVariants, CDP, DepVars);
        CombineChildVariants(N, AVariants, CBVariants, OutVariants, CDP, DepVars);
        return;
      }
    }
  
    // Compute permutations of all children.
    std::vector<std::vector<TreePatternNode*> > ChildVariants;
    ChildVariants.resize(N->getNumChildren());
    for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i)
      GenerateVariantsOf(N->getChild(i), ChildVariants[i], CDP, DepVars);
  
    // Build all permutations based on how the children were formed.
    CombineChildVariants(N, ChildVariants, OutVariants, CDP, DepVars);
  
    // If this node is commutative, consider the commuted order.
    bool isCommIntrinsic = N->isCommutativeIntrinsic(CDP);
    if (NodeInfo.hasProperty(SDNPCommutative) || isCommIntrinsic) {
      assert((N->getNumChildren()==2 || isCommIntrinsic) &&
             "Commutative but doesn't have 2 children!");
      // Don't count children which are actually register references.
      unsigned NC = 0;
      for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i) {
        TreePatternNode *Child = N->getChild(i);
        if (Child->isLeaf())
          if (DefInit *DI = dynamic_cast<DefInit*>(Child->getLeafValue())) {
            Record *RR = DI->getDef();
            if (RR->isSubClassOf("Register"))
              continue;
          }
        NC++;
      }
      // Consider the commuted order.
      if (isCommIntrinsic) {
        // Commutative intrinsic. First operand is the intrinsic id, 2nd and 3rd
        // operands are the commutative operands, and there might be more operands
        // after those.
        assert(NC >= 3 &&
               "Commutative intrinsic should have at least 3 childrean!");
        std::vector<std::vector<TreePatternNode*> > Variants;
        Variants.push_back(ChildVariants[0]); // Intrinsic id.
        Variants.push_back(ChildVariants[2]);
        Variants.push_back(ChildVariants[1]);
        for (unsigned i = 3; i != NC; ++i)
          Variants.push_back(ChildVariants[i]);
        CombineChildVariants(N, Variants, OutVariants, CDP, DepVars);
      } else if (NC == 2)
        CombineChildVariants(N, ChildVariants[1], ChildVariants[0],
                             OutVariants, CDP, DepVars);
    }
  }
  
  
  // GenerateVariants - Generate variants.  For example, commutative patterns can
  // match multiple ways.  Add them to PatternsToMatch as well.
  void CodeGenDAGPatterns::GenerateVariants() {
    DEBUG(errs() << "Generating instruction variants.\n");
  
    // Loop over all of the patterns we've collected, checking to see if we can
    // generate variants of the instruction, through the exploitation of
    // identities.  This permits the target to provide aggressive matching without
    // the .td file having to contain tons of variants of instructions.
    //
    // Note that this loop adds new patterns to the PatternsToMatch list, but we
    // intentionally do not reconsider these.  Any variants of added patterns have
    // already been added.
    //
    for (unsigned i = 0, e = PatternsToMatch.size(); i != e; ++i) {
      MultipleUseVarSet             DepVars;
      std::vector<TreePatternNode*> Variants;
      FindDepVars(PatternsToMatch[i].getSrcPattern(), DepVars);
      DEBUG(errs() << "Dependent/multiply used variables: ");
      DEBUG(DumpDepVars(DepVars));
      DEBUG(errs() << "\n");
      GenerateVariantsOf(PatternsToMatch[i].getSrcPattern(), Variants, *this,
                         DepVars);
  
      assert(!Variants.empty() && "Must create at least original variant!");
      Variants.erase(Variants.begin());  // Remove the original pattern.
  
      if (Variants.empty())  // No variants for this pattern.
        continue;
  
      DEBUG(errs() << "FOUND VARIANTS OF: ";
            PatternsToMatch[i].getSrcPattern()->dump();
            errs() << "\n");
  
      for (unsigned v = 0, e = Variants.size(); v != e; ++v) {
        TreePatternNode *Variant = Variants[v];
  
        DEBUG(errs() << "  VAR#" << v <<  ": ";
              Variant->dump();
              errs() << "\n");
  
        // Scan to see if an instruction or explicit pattern already matches this.
        bool AlreadyExists = false;
        for (unsigned p = 0, e = PatternsToMatch.size(); p != e; ++p) {
          // Skip if the top level predicates do not match.
          if (PatternsToMatch[i].getPredicates() !=
              PatternsToMatch[p].getPredicates())
            continue;
          // Check to see if this variant already exists.
          if (Variant->isIsomorphicTo(PatternsToMatch[p].getSrcPattern(),
                                      DepVars)) {
            DEBUG(errs() << "  *** ALREADY EXISTS, ignoring variant.\n");
            AlreadyExists = true;
            break;
          }
        }
        // If we already have it, ignore the variant.
        if (AlreadyExists) continue;
  
        // Otherwise, add it to the list of patterns we have.
        PatternsToMatch.
          push_back(PatternToMatch(PatternsToMatch[i].getSrcRecord(),
                                   PatternsToMatch[i].getPredicates(),
                                   Variant, PatternsToMatch[i].getDstPattern(),
                                   PatternsToMatch[i].getDstRegs(),
                                   PatternsToMatch[i].getAddedComplexity(),
                                   Record::getNewUID()));
      }
  
      DEBUG(errs() << "\n");
    }
  }
  
  