[llvm-commits] [llvm] r105105 - /llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

Dan Gohman gohman at apple.com
Sat May 29 10:53:24 PDT 2010


Author: djg
Date: Sat May 29 12:53:24 2010
New Revision: 105105

URL: http://llvm.org/viewvc/llvm-project?rev=105105&view=rev
Log:
Reorder some code in SelectionDAGBuilder.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=105105&r1=105104&r2=105105&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Sat May 29 12:53:24 2010
@@ -70,108 +70,6 @@
                  cl::location(LimitFloatPrecision),
                  cl::init(0));
 
-namespace {
-  /// RegsForValue - This struct represents the registers (physical or virtual)
-  /// that a particular set of values is assigned, and the type information
-  /// about the value. The most common situation is to represent one value at a
-  /// time, but struct or array values are handled element-wise as multiple
-  /// values.  The splitting of aggregates is performed recursively, so that we
-  /// never have aggregate-typed registers. The values at this point do not
-  /// necessarily have legal types, so each value may require one or more
-  /// registers of some legal type.
-  ///
-  struct RegsForValue {
-    /// ValueVTs - The value types of the values, which may not be legal, and
-    /// may need be promoted or synthesized from one or more registers.
-    ///
-    SmallVector<EVT, 4> ValueVTs;
-
-    /// RegVTs - The value types of the registers. This is the same size as
-    /// ValueVTs and it records, for each value, what the type of the assigned
-    /// register or registers are. (Individual values are never synthesized
-    /// from more than one type of register.)
-    ///
-    /// With virtual registers, the contents of RegVTs is redundant with TLI's
-    /// getRegisterType member function, however when with physical registers
-    /// it is necessary to have a separate record of the types.
-    ///
-    SmallVector<EVT, 4> RegVTs;
-
-    /// Regs - This list holds the registers assigned to the values.
-    /// Each legal or promoted value requires one register, and each
-    /// expanded value requires multiple registers.
-    ///
-    SmallVector<unsigned, 4> Regs;
-
-    RegsForValue() {}
-
-    RegsForValue(const SmallVector<unsigned, 4> &regs,
-                 EVT regvt, EVT valuevt)
-      : ValueVTs(1, valuevt), RegVTs(1, regvt), Regs(regs) {}
-
-    RegsForValue(const SmallVector<unsigned, 4> &regs,
-                 const SmallVector<EVT, 4> &regvts,
-                 const SmallVector<EVT, 4> &valuevts)
-      : ValueVTs(valuevts), RegVTs(regvts), Regs(regs) {}
-
-    RegsForValue(LLVMContext &Context, const TargetLowering &tli,
-                 unsigned Reg, const Type *Ty) {
-      ComputeValueVTs(tli, Ty, ValueVTs);
-
-      for (unsigned Value = 0, e = ValueVTs.size(); Value != e; ++Value) {
-        EVT ValueVT = ValueVTs[Value];
-        unsigned NumRegs = tli.getNumRegisters(Context, ValueVT);
-        EVT RegisterVT = tli.getRegisterType(Context, ValueVT);
-        for (unsigned i = 0; i != NumRegs; ++i)
-          Regs.push_back(Reg + i);
-        RegVTs.push_back(RegisterVT);
-        Reg += NumRegs;
-      }
-    }
-
-    /// areValueTypesLegal - Return true if types of all the values are legal.
-    bool areValueTypesLegal(const TargetLowering &TLI) {
-      for (unsigned Value = 0, e = ValueVTs.size(); Value != e; ++Value) {
-        EVT RegisterVT = RegVTs[Value];
-        if (!TLI.isTypeLegal(RegisterVT))
-          return false;
-      }
-      return true;
-    }
-
-    /// append - Add the specified values to this one.
-    void append(const RegsForValue &RHS) {
-      ValueVTs.append(RHS.ValueVTs.begin(), RHS.ValueVTs.end());
-      RegVTs.append(RHS.RegVTs.begin(), RHS.RegVTs.end());
-      Regs.append(RHS.Regs.begin(), RHS.Regs.end());
-    }
-
-
-    /// getCopyFromRegs - Emit a series of CopyFromReg nodes that copies from
-    /// this value and returns the result as a ValueVTs value.  This uses
-    /// Chain/Flag as the input and updates them for the output Chain/Flag.
-    /// If the Flag pointer is NULL, no flag is used.
-    SDValue getCopyFromRegs(SelectionDAG &DAG, FunctionLoweringInfo &FuncInfo,
-                            DebugLoc dl,
-                            SDValue &Chain, SDValue *Flag) const;
-
-    /// getCopyToRegs - Emit a series of CopyToReg nodes that copies the
-    /// specified value into the registers specified by this object.  This uses
-    /// Chain/Flag as the input and updates them for the output Chain/Flag.
-    /// If the Flag pointer is NULL, no flag is used.
-    void getCopyToRegs(SDValue Val, SelectionDAG &DAG, DebugLoc dl,
-                       SDValue &Chain, SDValue *Flag) const;
-
-    /// AddInlineAsmOperands - Add this value to the specified inlineasm node
-    /// operand list.  This adds the code marker, matching input operand index
-    /// (if applicable), and includes the number of values added into it.
-    void AddInlineAsmOperands(unsigned Kind,
-                              bool HasMatching, unsigned MatchingIdx,
-                              SelectionDAG &DAG,
-                              std::vector<SDValue> &Ops) const;
-  };
-}
-
 /// getCopyFromParts - Create a value that contains the specified legal parts
 /// combined into the value they represent.  If the parts combine to a type
 /// larger then ValueVT then AssertOp can be used to specify whether the extra
@@ -523,2418 +421,2680 @@
   }
 }
 
+namespace {
+  /// RegsForValue - This struct represents the registers (physical or virtual)
+  /// that a particular set of values is assigned, and the type information
+  /// about the value. The most common situation is to represent one value at a
+  /// time, but struct or array values are handled element-wise as multiple
+  /// values.  The splitting of aggregates is performed recursively, so that we
+  /// never have aggregate-typed registers. The values at this point do not
+  /// necessarily have legal types, so each value may require one or more
+  /// registers of some legal type.
+  ///
+  struct RegsForValue {
+    /// ValueVTs - The value types of the values, which may not be legal, and
+    /// may need be promoted or synthesized from one or more registers.
+    ///
+    SmallVector<EVT, 4> ValueVTs;
 
-void SelectionDAGBuilder::init(GCFunctionInfo *gfi, AliasAnalysis &aa) {
-  AA = &aa;
-  GFI = gfi;
-  TD = DAG.getTarget().getTargetData();
-}
-
-/// clear - Clear out the current SelectionDAG and the associated
-/// state and prepare this SelectionDAGBuilder object to be used
-/// for a new block. This doesn't clear out information about
-/// additional blocks that are needed to complete switch lowering
-/// or PHI node updating; that information is cleared out as it is
-/// consumed.
-void SelectionDAGBuilder::clear() {
-  NodeMap.clear();
-  PendingLoads.clear();
-  PendingExports.clear();
-  CurDebugLoc = DebugLoc();
-  HasTailCall = false;
-}
+    /// RegVTs - The value types of the registers. This is the same size as
+    /// ValueVTs and it records, for each value, what the type of the assigned
+    /// register or registers are. (Individual values are never synthesized
+    /// from more than one type of register.)
+    ///
+    /// With virtual registers, the contents of RegVTs is redundant with TLI's
+    /// getRegisterType member function, however when with physical registers
+    /// it is necessary to have a separate record of the types.
+    ///
+    SmallVector<EVT, 4> RegVTs;
 
-/// getRoot - Return the current virtual root of the Selection DAG,
-/// flushing any PendingLoad items. This must be done before emitting
-/// a store or any other node that may need to be ordered after any
-/// prior load instructions.
-///
-SDValue SelectionDAGBuilder::getRoot() {
-  if (PendingLoads.empty())
-    return DAG.getRoot();
+    /// Regs - This list holds the registers assigned to the values.
+    /// Each legal or promoted value requires one register, and each
+    /// expanded value requires multiple registers.
+    ///
+    SmallVector<unsigned, 4> Regs;
 
-  if (PendingLoads.size() == 1) {
-    SDValue Root = PendingLoads[0];
-    DAG.setRoot(Root);
-    PendingLoads.clear();
-    return Root;
-  }
+    RegsForValue() {}
 
-  // Otherwise, we have to make a token factor node.
-  SDValue Root = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(), MVT::Other,
-                               &PendingLoads[0], PendingLoads.size());
-  PendingLoads.clear();
-  DAG.setRoot(Root);
-  return Root;
-}
+    RegsForValue(const SmallVector<unsigned, 4> &regs,
+                 EVT regvt, EVT valuevt)
+      : ValueVTs(1, valuevt), RegVTs(1, regvt), Regs(regs) {}
 
-/// getControlRoot - Similar to getRoot, but instead of flushing all the
-/// PendingLoad items, flush all the PendingExports items. It is necessary
-/// to do this before emitting a terminator instruction.
-///
-SDValue SelectionDAGBuilder::getControlRoot() {
-  SDValue Root = DAG.getRoot();
+    RegsForValue(const SmallVector<unsigned, 4> &regs,
+                 const SmallVector<EVT, 4> &regvts,
+                 const SmallVector<EVT, 4> &valuevts)
+      : ValueVTs(valuevts), RegVTs(regvts), Regs(regs) {}
 
-  if (PendingExports.empty())
-    return Root;
+    RegsForValue(LLVMContext &Context, const TargetLowering &tli,
+                 unsigned Reg, const Type *Ty) {
+      ComputeValueVTs(tli, Ty, ValueVTs);
 
-  // Turn all of the CopyToReg chains into one factored node.
-  if (Root.getOpcode() != ISD::EntryToken) {
-    unsigned i = 0, e = PendingExports.size();
-    for (; i != e; ++i) {
-      assert(PendingExports[i].getNode()->getNumOperands() > 1);
-      if (PendingExports[i].getNode()->getOperand(0) == Root)
-        break;  // Don't add the root if we already indirectly depend on it.
+      for (unsigned Value = 0, e = ValueVTs.size(); Value != e; ++Value) {
+        EVT ValueVT = ValueVTs[Value];
+        unsigned NumRegs = tli.getNumRegisters(Context, ValueVT);
+        EVT RegisterVT = tli.getRegisterType(Context, ValueVT);
+        for (unsigned i = 0; i != NumRegs; ++i)
+          Regs.push_back(Reg + i);
+        RegVTs.push_back(RegisterVT);
+        Reg += NumRegs;
+      }
     }
 
-    if (i == e)
-      PendingExports.push_back(Root);
-  }
-
-  Root = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(), MVT::Other,
-                     &PendingExports[0],
-                     PendingExports.size());
-  PendingExports.clear();
-  DAG.setRoot(Root);
-  return Root;
-}
+    /// areValueTypesLegal - Return true if types of all the values are legal.
+    bool areValueTypesLegal(const TargetLowering &TLI) {
+      for (unsigned Value = 0, e = ValueVTs.size(); Value != e; ++Value) {
+        EVT RegisterVT = RegVTs[Value];
+        if (!TLI.isTypeLegal(RegisterVT))
+          return false;
+      }
+      return true;
+    }
 
-void SelectionDAGBuilder::AssignOrderingToNode(const SDNode *Node) {
-  if (DAG.GetOrdering(Node) != 0) return; // Already has ordering.
-  DAG.AssignOrdering(Node, SDNodeOrder);
+    /// append - Add the specified values to this one.
+    void append(const RegsForValue &RHS) {
+      ValueVTs.append(RHS.ValueVTs.begin(), RHS.ValueVTs.end());
+      RegVTs.append(RHS.RegVTs.begin(), RHS.RegVTs.end());
+      Regs.append(RHS.Regs.begin(), RHS.Regs.end());
+    }
 
-  for (unsigned I = 0, E = Node->getNumOperands(); I != E; ++I)
-    AssignOrderingToNode(Node->getOperand(I).getNode());
-}
+    /// getCopyFromRegs - Emit a series of CopyFromReg nodes that copies from
+    /// this value and returns the result as a ValueVTs value.  This uses
+    /// Chain/Flag as the input and updates them for the output Chain/Flag.
+    /// If the Flag pointer is NULL, no flag is used.
+    SDValue getCopyFromRegs(SelectionDAG &DAG, FunctionLoweringInfo &FuncInfo,
+                            DebugLoc dl,
+                            SDValue &Chain, SDValue *Flag) const;
 
-void SelectionDAGBuilder::visit(const Instruction &I) {
-  // Set up outgoing PHI node register values before emitting the terminator.
-  if (isa<TerminatorInst>(&I))
-    HandlePHINodesInSuccessorBlocks(I.getParent());
+    /// getCopyToRegs - Emit a series of CopyToReg nodes that copies the
+    /// specified value into the registers specified by this object.  This uses
+    /// Chain/Flag as the input and updates them for the output Chain/Flag.
+    /// If the Flag pointer is NULL, no flag is used.
+    void getCopyToRegs(SDValue Val, SelectionDAG &DAG, DebugLoc dl,
+                       SDValue &Chain, SDValue *Flag) const;
 
-  CurDebugLoc = I.getDebugLoc();
-
-  visit(I.getOpcode(), I);
-
-  if (!isa<TerminatorInst>(&I) && !HasTailCall)
-    CopyToExportRegsIfNeeded(&I);
-
-  CurDebugLoc = DebugLoc();
-}
-
-void SelectionDAGBuilder::visitPHI(const PHINode &) {
-  llvm_unreachable("SelectionDAGBuilder shouldn't visit PHI nodes!");
-}
-
-void SelectionDAGBuilder::visit(unsigned Opcode, const User &I) {
-  // Note: this doesn't use InstVisitor, because it has to work with
-  // ConstantExpr's in addition to instructions.
-  switch (Opcode) {
-  default: llvm_unreachable("Unknown instruction type encountered!");
-    // Build the switch statement using the Instruction.def file.
-#define HANDLE_INST(NUM, OPCODE, CLASS) \
-    case Instruction::OPCODE: visit##OPCODE((CLASS&)I); break;
-#include "llvm/Instruction.def"
-  }
-
-  // Assign the ordering to the freshly created DAG nodes.
-  if (NodeMap.count(&I)) {
-    ++SDNodeOrder;
-    AssignOrderingToNode(getValue(&I).getNode());
-  }
+    /// AddInlineAsmOperands - Add this value to the specified inlineasm node
+    /// operand list.  This adds the code marker, matching input operand index
+    /// (if applicable), and includes the number of values added into it.
+    void AddInlineAsmOperands(unsigned Kind,
+                              bool HasMatching, unsigned MatchingIdx,
+                              SelectionDAG &DAG,
+                              std::vector<SDValue> &Ops) const;
+  };
 }
 
-SDValue SelectionDAGBuilder::getValue(const Value *V) {
-  SDValue &N = NodeMap[V];
-  if (N.getNode()) return N;
-
-  if (const Constant *C = dyn_cast<Constant>(V)) {
-    EVT VT = TLI.getValueType(V->getType(), true);
+/// getCopyFromRegs - Emit a series of CopyFromReg nodes that copies from
+/// this value and returns the result as a ValueVT value.  This uses
+/// Chain/Flag as the input and updates them for the output Chain/Flag.
+/// If the Flag pointer is NULL, no flag is used.
+SDValue RegsForValue::getCopyFromRegs(SelectionDAG &DAG,
+                                      FunctionLoweringInfo &FuncInfo,
+                                      DebugLoc dl,
+                                      SDValue &Chain, SDValue *Flag) const {
+  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
 
-    if (const ConstantInt *CI = dyn_cast<ConstantInt>(C))
-      return N = DAG.getConstant(*CI, VT);
+  // Assemble the legal parts into the final values.
+  SmallVector<SDValue, 4> Values(ValueVTs.size());
+  SmallVector<SDValue, 8> Parts;
+  for (unsigned Value = 0, Part = 0, e = ValueVTs.size(); Value != e; ++Value) {
+    // Copy the legal parts from the registers.
+    EVT ValueVT = ValueVTs[Value];
+    unsigned NumRegs = TLI.getNumRegisters(*DAG.getContext(), ValueVT);
+    EVT RegisterVT = RegVTs[Value];
 
-    if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
-      return N = DAG.getGlobalAddress(GV, VT);
+    Parts.resize(NumRegs);
+    for (unsigned i = 0; i != NumRegs; ++i) {
+      SDValue P;
+      if (Flag == 0) {
+        P = DAG.getCopyFromReg(Chain, dl, Regs[Part+i], RegisterVT);
+      } else {
+        P = DAG.getCopyFromReg(Chain, dl, Regs[Part+i], RegisterVT, *Flag);
+        *Flag = P.getValue(2);
+      }
 
-    if (isa<ConstantPointerNull>(C))
-      return N = DAG.getConstant(0, TLI.getPointerTy());
+      Chain = P.getValue(1);
 
-    if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C))
-      return N = DAG.getConstantFP(*CFP, VT);
+      // If the source register was virtual and if we know something about it,
+      // add an assert node.
+      if (TargetRegisterInfo::isVirtualRegister(Regs[Part+i]) &&
+          RegisterVT.isInteger() && !RegisterVT.isVector()) {
+        unsigned SlotNo = Regs[Part+i]-TargetRegisterInfo::FirstVirtualRegister;
+        if (FuncInfo.LiveOutRegInfo.size() > SlotNo) {
+          const FunctionLoweringInfo::LiveOutInfo &LOI =
+            FuncInfo.LiveOutRegInfo[SlotNo];
 
-    if (isa<UndefValue>(C) && !V->getType()->isAggregateType())
-      return N = DAG.getUNDEF(VT);
+          unsigned RegSize = RegisterVT.getSizeInBits();
+          unsigned NumSignBits = LOI.NumSignBits;
+          unsigned NumZeroBits = LOI.KnownZero.countLeadingOnes();
 
-    if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
-      visit(CE->getOpcode(), *CE);
-      SDValue N1 = NodeMap[V];
-      assert(N1.getNode() && "visit didn't populate the NodeMap!");
-      return N1;
-    }
+          // FIXME: We capture more information than the dag can represent.  For
+          // now, just use the tightest assertzext/assertsext possible.
+          bool isSExt = true;
+          EVT FromVT(MVT::Other);
+          if (NumSignBits == RegSize)
+            isSExt = true, FromVT = MVT::i1;   // ASSERT SEXT 1
+          else if (NumZeroBits >= RegSize-1)
+            isSExt = false, FromVT = MVT::i1;  // ASSERT ZEXT 1
+          else if (NumSignBits > RegSize-8)
+            isSExt = true, FromVT = MVT::i8;   // ASSERT SEXT 8
+          else if (NumZeroBits >= RegSize-8)
+            isSExt = false, FromVT = MVT::i8;  // ASSERT ZEXT 8
+          else if (NumSignBits > RegSize-16)
+            isSExt = true, FromVT = MVT::i16;  // ASSERT SEXT 16
+          else if (NumZeroBits >= RegSize-16)
+            isSExt = false, FromVT = MVT::i16; // ASSERT ZEXT 16
+          else if (NumSignBits > RegSize-32)
+            isSExt = true, FromVT = MVT::i32;  // ASSERT SEXT 32
+          else if (NumZeroBits >= RegSize-32)
+            isSExt = false, FromVT = MVT::i32; // ASSERT ZEXT 32
 
-    if (isa<ConstantStruct>(C) || isa<ConstantArray>(C)) {
-      SmallVector<SDValue, 4> Constants;
-      for (User::const_op_iterator OI = C->op_begin(), OE = C->op_end();
-           OI != OE; ++OI) {
-        SDNode *Val = getValue(*OI).getNode();
-        // If the operand is an empty aggregate, there are no values.
-        if (!Val) continue;
-        // Add each leaf value from the operand to the Constants list
-        // to form a flattened list of all the values.
-        for (unsigned i = 0, e = Val->getNumValues(); i != e; ++i)
-          Constants.push_back(SDValue(Val, i));
+          if (FromVT != MVT::Other)
+            P = DAG.getNode(isSExt ? ISD::AssertSext : ISD::AssertZext, dl,
+                            RegisterVT, P, DAG.getValueType(FromVT));
+        }
       }
 
-      return DAG.getMergeValues(&Constants[0], Constants.size(),
-                                getCurDebugLoc());
+      Parts[i] = P;
     }
 
-    if (C->getType()->isStructTy() || C->getType()->isArrayTy()) {
-      assert((isa<ConstantAggregateZero>(C) || isa<UndefValue>(C)) &&
-             "Unknown struct or array constant!");
+    Values[Value] = getCopyFromParts(DAG, dl, Parts.begin(),
+                                     NumRegs, RegisterVT, ValueVT);
+    Part += NumRegs;
+    Parts.clear();
+  }
 
-      SmallVector<EVT, 4> ValueVTs;
-      ComputeValueVTs(TLI, C->getType(), ValueVTs);
-      unsigned NumElts = ValueVTs.size();
-      if (NumElts == 0)
-        return SDValue(); // empty struct
-      SmallVector<SDValue, 4> Constants(NumElts);
-      for (unsigned i = 0; i != NumElts; ++i) {
-        EVT EltVT = ValueVTs[i];
-        if (isa<UndefValue>(C))
-          Constants[i] = DAG.getUNDEF(EltVT);
-        else if (EltVT.isFloatingPoint())
-          Constants[i] = DAG.getConstantFP(0, EltVT);
-        else
-          Constants[i] = DAG.getConstant(0, EltVT);
-      }
+  return DAG.getNode(ISD::MERGE_VALUES, dl,
+                     DAG.getVTList(&ValueVTs[0], ValueVTs.size()),
+                     &Values[0], ValueVTs.size());
+}
 
-      return DAG.getMergeValues(&Constants[0], NumElts,
-                                getCurDebugLoc());
-    }
+/// getCopyToRegs - Emit a series of CopyToReg nodes that copies the
+/// specified value into the registers specified by this object.  This uses
+/// Chain/Flag as the input and updates them for the output Chain/Flag.
+/// If the Flag pointer is NULL, no flag is used.
+void RegsForValue::getCopyToRegs(SDValue Val, SelectionDAG &DAG, DebugLoc dl,
+                                 SDValue &Chain, SDValue *Flag) const {
+  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
 
-    if (const BlockAddress *BA = dyn_cast<BlockAddress>(C))
-      return DAG.getBlockAddress(BA, VT);
+  // Get the list of the values's legal parts.
+  unsigned NumRegs = Regs.size();
+  SmallVector<SDValue, 8> Parts(NumRegs);
+  for (unsigned Value = 0, Part = 0, e = ValueVTs.size(); Value != e; ++Value) {
+    EVT ValueVT = ValueVTs[Value];
+    unsigned NumParts = TLI.getNumRegisters(*DAG.getContext(), ValueVT);
+    EVT RegisterVT = RegVTs[Value];
 
-    const VectorType *VecTy = cast<VectorType>(V->getType());
-    unsigned NumElements = VecTy->getNumElements();
+    getCopyToParts(DAG, dl,
+                   Val.getValue(Val.getResNo() + Value),
+                   &Parts[Part], NumParts, RegisterVT);
+    Part += NumParts;
+  }
 
-    // Now that we know the number and type of the elements, get that number of
-    // elements into the Ops array based on what kind of constant it is.
-    SmallVector<SDValue, 16> Ops;
-    if (const ConstantVector *CP = dyn_cast<ConstantVector>(C)) {
-      for (unsigned i = 0; i != NumElements; ++i)
-        Ops.push_back(getValue(CP->getOperand(i)));
+  // Copy the parts into the registers.
+  SmallVector<SDValue, 8> Chains(NumRegs);
+  for (unsigned i = 0; i != NumRegs; ++i) {
+    SDValue Part;
+    if (Flag == 0) {
+      Part = DAG.getCopyToReg(Chain, dl, Regs[i], Parts[i]);
     } else {
-      assert(isa<ConstantAggregateZero>(C) && "Unknown vector constant!");
-      EVT EltVT = TLI.getValueType(VecTy->getElementType());
-
-      SDValue Op;
-      if (EltVT.isFloatingPoint())
-        Op = DAG.getConstantFP(0, EltVT);
-      else
-        Op = DAG.getConstant(0, EltVT);
-      Ops.assign(NumElements, Op);
+      Part = DAG.getCopyToReg(Chain, dl, Regs[i], Parts[i], *Flag);
+      *Flag = Part.getValue(1);
     }
 
-    // Create a BUILD_VECTOR node.
-    return NodeMap[V] = DAG.getNode(ISD::BUILD_VECTOR, getCurDebugLoc(),
-                                    VT, &Ops[0], Ops.size());
-  }
-
-  // If this is a static alloca, generate it as the frameindex instead of
-  // computation.
-  if (const AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
-    DenseMap<const AllocaInst*, int>::iterator SI =
-      FuncInfo.StaticAllocaMap.find(AI);
-    if (SI != FuncInfo.StaticAllocaMap.end())
-      return DAG.getFrameIndex(SI->second, TLI.getPointerTy());
+    Chains[i] = Part.getValue(0);
   }
 
-  unsigned InReg = FuncInfo.ValueMap[V];
-  assert(InReg && "Value not in map!");
-
-  RegsForValue RFV(*DAG.getContext(), TLI, InReg, V->getType());
-  SDValue Chain = DAG.getEntryNode();
-  return RFV.getCopyFromRegs(DAG, FuncInfo, getCurDebugLoc(), Chain, NULL);
+  if (NumRegs == 1 || Flag)
+    // If NumRegs > 1 && Flag is used then the use of the last CopyToReg is
+    // flagged to it. That is the CopyToReg nodes and the user are considered
+    // a single scheduling unit. If we create a TokenFactor and return it as
+    // chain, then the TokenFactor is both a predecessor (operand) of the
+    // user as well as a successor (the TF operands are flagged to the user).
+    // c1, f1 = CopyToReg
+    // c2, f2 = CopyToReg
+    // c3     = TokenFactor c1, c2
+    // ...
+    //        = op c3, ..., f2
+    Chain = Chains[NumRegs-1];
+  else
+    Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &Chains[0], NumRegs);
 }
 
-/// Get the EVTs and ArgFlags collections that represent the legalized return 
-/// type of the given function.  This does not require a DAG or a return value,
-/// and is suitable for use before any DAGs for the function are constructed.
-static void getReturnInfo(const Type* ReturnType,
-                   Attributes attr, SmallVectorImpl<EVT> &OutVTs,
-                   SmallVectorImpl<ISD::ArgFlagsTy> &OutFlags,
-                   const TargetLowering &TLI,
-                   SmallVectorImpl<uint64_t> *Offsets = 0) {
-  SmallVector<EVT, 4> ValueVTs;
-  ComputeValueVTs(TLI, ReturnType, ValueVTs);
-  unsigned NumValues = ValueVTs.size();
-  if (NumValues == 0) return;
-  unsigned Offset = 0;
-
-  for (unsigned j = 0, f = NumValues; j != f; ++j) {
-    EVT VT = ValueVTs[j];
-    ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
+/// AddInlineAsmOperands - Add this value to the specified inlineasm node
+/// operand list.  This adds the code marker and includes the number of
+/// values added into it.
+void RegsForValue::AddInlineAsmOperands(unsigned Code, bool HasMatching,
+                                        unsigned MatchingIdx,
+                                        SelectionDAG &DAG,
+                                        std::vector<SDValue> &Ops) const {
+  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
 
-    if (attr & Attribute::SExt)
-      ExtendKind = ISD::SIGN_EXTEND;
-    else if (attr & Attribute::ZExt)
-      ExtendKind = ISD::ZERO_EXTEND;
+  unsigned Flag = InlineAsm::getFlagWord(Code, Regs.size());
+  if (HasMatching)
+    Flag = InlineAsm::getFlagWordForMatchingOp(Flag, MatchingIdx);
+  SDValue Res = DAG.getTargetConstant(Flag, MVT::i32);
+  Ops.push_back(Res);
 
-    // FIXME: C calling convention requires the return type to be promoted to
-    // at least 32-bit. But this is not necessary for non-C calling
-    // conventions. The frontend should mark functions whose return values
-    // require promoting with signext or zeroext attributes.
-    if (ExtendKind != ISD::ANY_EXTEND && VT.isInteger()) {
-      EVT MinVT = TLI.getRegisterType(ReturnType->getContext(), MVT::i32);
-      if (VT.bitsLT(MinVT))
-        VT = MinVT;
+  for (unsigned Value = 0, Reg = 0, e = ValueVTs.size(); Value != e; ++Value) {
+    unsigned NumRegs = TLI.getNumRegisters(*DAG.getContext(), ValueVTs[Value]);
+    EVT RegisterVT = RegVTs[Value];
+    for (unsigned i = 0; i != NumRegs; ++i) {
+      assert(Reg < Regs.size() && "Mismatch in # registers expected");
+      Ops.push_back(DAG.getRegister(Regs[Reg++], RegisterVT));
     }
+  }
+}
 
-    unsigned NumParts = TLI.getNumRegisters(ReturnType->getContext(), VT);
-    EVT PartVT = TLI.getRegisterType(ReturnType->getContext(), VT);
-    unsigned PartSize = TLI.getTargetData()->getTypeAllocSize(
-                        PartVT.getTypeForEVT(ReturnType->getContext()));
-
-    // 'inreg' on function refers to return value
-    ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy();
-    if (attr & Attribute::InReg)
-      Flags.setInReg();
-
-    // Propagate extension type if any
-    if (attr & Attribute::SExt)
-      Flags.setSExt();
-    else if (attr & Attribute::ZExt)
-      Flags.setZExt();
+void SelectionDAGBuilder::init(GCFunctionInfo *gfi, AliasAnalysis &aa) {
+  AA = &aa;
+  GFI = gfi;
+  TD = DAG.getTarget().getTargetData();
+}
 
-    for (unsigned i = 0; i < NumParts; ++i) {
-      OutVTs.push_back(PartVT);
-      OutFlags.push_back(Flags);
-      if (Offsets)
-      {
-        Offsets->push_back(Offset);
-        Offset += PartSize;
-      }
-    }
-  }
+/// clear - Clear out the current SelectionDAG and the associated
+/// state and prepare this SelectionDAGBuilder object to be used
+/// for a new block. This doesn't clear out information about
+/// additional blocks that are needed to complete switch lowering
+/// or PHI node updating; that information is cleared out as it is
+/// consumed.
+void SelectionDAGBuilder::clear() {
+  NodeMap.clear();
+  PendingLoads.clear();
+  PendingExports.clear();
+  CurDebugLoc = DebugLoc();
+  HasTailCall = false;
 }
 
-void SelectionDAGBuilder::visitRet(const ReturnInst &I) {
-  SDValue Chain = getControlRoot();
-  SmallVector<ISD::OutputArg, 8> Outs;
+/// getRoot - Return the current virtual root of the Selection DAG,
+/// flushing any PendingLoad items. This must be done before emitting
+/// a store or any other node that may need to be ordered after any
+/// prior load instructions.
+///
+SDValue SelectionDAGBuilder::getRoot() {
+  if (PendingLoads.empty())
+    return DAG.getRoot();
 
-  if (!FuncInfo.CanLowerReturn) {
-    unsigned DemoteReg = FuncInfo.DemoteRegister;
-    const Function *F = I.getParent()->getParent();
+  if (PendingLoads.size() == 1) {
+    SDValue Root = PendingLoads[0];
+    DAG.setRoot(Root);
+    PendingLoads.clear();
+    return Root;
+  }
 
-    // Emit a store of the return value through the virtual register.
-    // Leave Outs empty so that LowerReturn won't try to load return
-    // registers the usual way.
-    SmallVector<EVT, 1> PtrValueVTs;
-    ComputeValueVTs(TLI, PointerType::getUnqual(F->getReturnType()),
-                    PtrValueVTs);
+  // Otherwise, we have to make a token factor node.
+  SDValue Root = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(), MVT::Other,
+                               &PendingLoads[0], PendingLoads.size());
+  PendingLoads.clear();
+  DAG.setRoot(Root);
+  return Root;
+}
 
-    SDValue RetPtr = DAG.getRegister(DemoteReg, PtrValueVTs[0]);
-    SDValue RetOp = getValue(I.getOperand(0));
+/// getControlRoot - Similar to getRoot, but instead of flushing all the
+/// PendingLoad items, flush all the PendingExports items. It is necessary
+/// to do this before emitting a terminator instruction.
+///
+SDValue SelectionDAGBuilder::getControlRoot() {
+  SDValue Root = DAG.getRoot();
 
-    SmallVector<EVT, 4> ValueVTs;
-    SmallVector<uint64_t, 4> Offsets;
-    ComputeValueVTs(TLI, I.getOperand(0)->getType(), ValueVTs, &Offsets);
-    unsigned NumValues = ValueVTs.size();
+  if (PendingExports.empty())
+    return Root;
 
-    SmallVector<SDValue, 4> Chains(NumValues);
-    EVT PtrVT = PtrValueVTs[0];
-    for (unsigned i = 0; i != NumValues; ++i) {
-      SDValue Add = DAG.getNode(ISD::ADD, getCurDebugLoc(), PtrVT, RetPtr,
-                                DAG.getConstant(Offsets[i], PtrVT));
-      Chains[i] =
-        DAG.getStore(Chain, getCurDebugLoc(),
-                     SDValue(RetOp.getNode(), RetOp.getResNo() + i),
-                     Add, NULL, Offsets[i], false, false, 0);
+  // Turn all of the CopyToReg chains into one factored node.
+  if (Root.getOpcode() != ISD::EntryToken) {
+    unsigned i = 0, e = PendingExports.size();
+    for (; i != e; ++i) {
+      assert(PendingExports[i].getNode()->getNumOperands() > 1);
+      if (PendingExports[i].getNode()->getOperand(0) == Root)
+        break;  // Don't add the root if we already indirectly depend on it.
     }
 
-    Chain = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(),
-                        MVT::Other, &Chains[0], NumValues);
-  } else if (I.getNumOperands() != 0) {
-    SmallVector<EVT, 4> ValueVTs;
-    ComputeValueVTs(TLI, I.getOperand(0)->getType(), ValueVTs);
-    unsigned NumValues = ValueVTs.size();
-    if (NumValues) {
-      SDValue RetOp = getValue(I.getOperand(0));
-      for (unsigned j = 0, f = NumValues; j != f; ++j) {
-        EVT VT = ValueVTs[j];
-
-        ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
+    if (i == e)
+      PendingExports.push_back(Root);
+  }
 
-        const Function *F = I.getParent()->getParent();
-        if (F->paramHasAttr(0, Attribute::SExt))
-          ExtendKind = ISD::SIGN_EXTEND;
-        else if (F->paramHasAttr(0, Attribute::ZExt))
-          ExtendKind = ISD::ZERO_EXTEND;
+  Root = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(), MVT::Other,
+                     &PendingExports[0],
+                     PendingExports.size());
+  PendingExports.clear();
+  DAG.setRoot(Root);
+  return Root;
+}
 
-        // FIXME: C calling convention requires the return type to be promoted
-        // to at least 32-bit. But this is not necessary for non-C calling
-        // conventions. The frontend should mark functions whose return values
-        // require promoting with signext or zeroext attributes.
-        if (ExtendKind != ISD::ANY_EXTEND && VT.isInteger()) {
-          EVT MinVT = TLI.getRegisterType(*DAG.getContext(), MVT::i32);
-          if (VT.bitsLT(MinVT))
-            VT = MinVT;
-        }
+void SelectionDAGBuilder::AssignOrderingToNode(const SDNode *Node) {
+  if (DAG.GetOrdering(Node) != 0) return; // Already has ordering.
+  DAG.AssignOrdering(Node, SDNodeOrder);
 
-        unsigned NumParts = TLI.getNumRegisters(*DAG.getContext(), VT);
-        EVT PartVT = TLI.getRegisterType(*DAG.getContext(), VT);
-        SmallVector<SDValue, 4> Parts(NumParts);
-        getCopyToParts(DAG, getCurDebugLoc(),
-                       SDValue(RetOp.getNode(), RetOp.getResNo() + j),
-                       &Parts[0], NumParts, PartVT, ExtendKind);
+  for (unsigned I = 0, E = Node->getNumOperands(); I != E; ++I)
+    AssignOrderingToNode(Node->getOperand(I).getNode());
+}
 
-        // 'inreg' on function refers to return value
-        ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy();
-        if (F->paramHasAttr(0, Attribute::InReg))
-          Flags.setInReg();
+void SelectionDAGBuilder::visit(const Instruction &I) {
+  // Set up outgoing PHI node register values before emitting the terminator.
+  if (isa<TerminatorInst>(&I))
+    HandlePHINodesInSuccessorBlocks(I.getParent());
 
-        // Propagate extension type if any
-        if (F->paramHasAttr(0, Attribute::SExt))
-          Flags.setSExt();
-        else if (F->paramHasAttr(0, Attribute::ZExt))
-          Flags.setZExt();
+  CurDebugLoc = I.getDebugLoc();
 
-        for (unsigned i = 0; i < NumParts; ++i)
-          Outs.push_back(ISD::OutputArg(Flags, Parts[i], /*isfixed=*/true));
-      }
-    }
-  }
+  visit(I.getOpcode(), I);
 
-  bool isVarArg = DAG.getMachineFunction().getFunction()->isVarArg();
-  CallingConv::ID CallConv =
-    DAG.getMachineFunction().getFunction()->getCallingConv();
-  Chain = TLI.LowerReturn(Chain, CallConv, isVarArg,
-                          Outs, getCurDebugLoc(), DAG);
+  if (!isa<TerminatorInst>(&I) && !HasTailCall)
+    CopyToExportRegsIfNeeded(&I);
 
-  // Verify that the target's LowerReturn behaved as expected.
-  assert(Chain.getNode() && Chain.getValueType() == MVT::Other &&
-         "LowerReturn didn't return a valid chain!");
+  CurDebugLoc = DebugLoc();
+}
 
-  // Update the DAG with the new chain value resulting from return lowering.
-  DAG.setRoot(Chain);
+void SelectionDAGBuilder::visitPHI(const PHINode &) {
+  llvm_unreachable("SelectionDAGBuilder shouldn't visit PHI nodes!");
 }
 
-/// CopyToExportRegsIfNeeded - If the given value has virtual registers
-/// created for it, emit nodes to copy the value into the virtual
-/// registers.
-void SelectionDAGBuilder::CopyToExportRegsIfNeeded(const Value *V) {
-  DenseMap<const Value *, unsigned>::iterator VMI = FuncInfo.ValueMap.find(V);
-  if (VMI != FuncInfo.ValueMap.end()) {
-    assert(!V->use_empty() && "Unused value assigned virtual registers!");
-    CopyValueToVirtualRegister(V, VMI->second);
+void SelectionDAGBuilder::visit(unsigned Opcode, const User &I) {
+  // Note: this doesn't use InstVisitor, because it has to work with
+  // ConstantExpr's in addition to instructions.
+  switch (Opcode) {
+  default: llvm_unreachable("Unknown instruction type encountered!");
+    // Build the switch statement using the Instruction.def file.
+#define HANDLE_INST(NUM, OPCODE, CLASS) \
+    case Instruction::OPCODE: visit##OPCODE((CLASS&)I); break;
+#include "llvm/Instruction.def"
+  }
+
+  // Assign the ordering to the freshly created DAG nodes.
+  if (NodeMap.count(&I)) {
+    ++SDNodeOrder;
+    AssignOrderingToNode(getValue(&I).getNode());
   }
 }
 
-/// ExportFromCurrentBlock - If this condition isn't known to be exported from
-/// the current basic block, add it to ValueMap now so that we'll get a
-/// CopyTo/FromReg.
-void SelectionDAGBuilder::ExportFromCurrentBlock(const Value *V) {
-  // No need to export constants.
-  if (!isa<Instruction>(V) && !isa<Argument>(V)) return;
-
-  // Already exported?
-  if (FuncInfo.isExportedInst(V)) return;
-
-  unsigned Reg = FuncInfo.InitializeRegForValue(V);
-  CopyValueToVirtualRegister(V, Reg);
-}
+SDValue SelectionDAGBuilder::getValue(const Value *V) {
+  SDValue &N = NodeMap[V];
+  if (N.getNode()) return N;
 
-bool SelectionDAGBuilder::isExportableFromCurrentBlock(const Value *V,
-                                                     const BasicBlock *FromBB) {
-  // The operands of the setcc have to be in this block.  We don't know
-  // how to export them from some other block.
-  if (const Instruction *VI = dyn_cast<Instruction>(V)) {
-    // Can export from current BB.
-    if (VI->getParent() == FromBB)
-      return true;
+  if (const Constant *C = dyn_cast<Constant>(V)) {
+    EVT VT = TLI.getValueType(V->getType(), true);
 
-    // Is already exported, noop.
-    return FuncInfo.isExportedInst(V);
-  }
+    if (const ConstantInt *CI = dyn_cast<ConstantInt>(C))
+      return N = DAG.getConstant(*CI, VT);
 
-  // If this is an argument, we can export it if the BB is the entry block or
-  // if it is already exported.
-  if (isa<Argument>(V)) {
-    if (FromBB == &FromBB->getParent()->getEntryBlock())
-      return true;
+    if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
+      return N = DAG.getGlobalAddress(GV, VT);
 
-    // Otherwise, can only export this if it is already exported.
-    return FuncInfo.isExportedInst(V);
-  }
+    if (isa<ConstantPointerNull>(C))
+      return N = DAG.getConstant(0, TLI.getPointerTy());
 
-  // Otherwise, constants can always be exported.
-  return true;
-}
+    if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C))
+      return N = DAG.getConstantFP(*CFP, VT);
 
-static bool InBlock(const Value *V, const BasicBlock *BB) {
-  if (const Instruction *I = dyn_cast<Instruction>(V))
-    return I->getParent() == BB;
-  return true;
-}
+    if (isa<UndefValue>(C) && !V->getType()->isAggregateType())
+      return N = DAG.getUNDEF(VT);
 
-/// EmitBranchForMergedCondition - Helper method for FindMergedConditions.
-/// This function emits a branch and is used at the leaves of an OR or an
-/// AND operator tree.
-///
-void
-SelectionDAGBuilder::EmitBranchForMergedCondition(const Value *Cond,
-                                                  MachineBasicBlock *TBB,
-                                                  MachineBasicBlock *FBB,
-                                                  MachineBasicBlock *CurBB,
-                                                  MachineBasicBlock *SwitchBB) {
-  const BasicBlock *BB = CurBB->getBasicBlock();
+    if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
+      visit(CE->getOpcode(), *CE);
+      SDValue N1 = NodeMap[V];
+      assert(N1.getNode() && "visit didn't populate the NodeMap!");
+      return N1;
+    }
 
-  // If the leaf of the tree is a comparison, merge the condition into
-  // the caseblock.
-  if (const CmpInst *BOp = dyn_cast<CmpInst>(Cond)) {
-    // The operands of the cmp have to be in this block.  We don't know
-    // how to export them from some other block.  If this is the first block
-    // of the sequence, no exporting is needed.
-    if (CurBB == SwitchBB ||
-        (isExportableFromCurrentBlock(BOp->getOperand(0), BB) &&
-         isExportableFromCurrentBlock(BOp->getOperand(1), BB))) {
-      ISD::CondCode Condition;
-      if (const ICmpInst *IC = dyn_cast<ICmpInst>(Cond)) {
-        Condition = getICmpCondCode(IC->getPredicate());
-      } else if (const FCmpInst *FC = dyn_cast<FCmpInst>(Cond)) {
-        Condition = getFCmpCondCode(FC->getPredicate());
-      } else {
-        Condition = ISD::SETEQ; // silence warning.
-        llvm_unreachable("Unknown compare instruction");
+    if (isa<ConstantStruct>(C) || isa<ConstantArray>(C)) {
+      SmallVector<SDValue, 4> Constants;
+      for (User::const_op_iterator OI = C->op_begin(), OE = C->op_end();
+           OI != OE; ++OI) {
+        SDNode *Val = getValue(*OI).getNode();
+        // If the operand is an empty aggregate, there are no values.
+        if (!Val) continue;
+        // Add each leaf value from the operand to the Constants list
+        // to form a flattened list of all the values.
+        for (unsigned i = 0, e = Val->getNumValues(); i != e; ++i)
+          Constants.push_back(SDValue(Val, i));
       }
 
-      CaseBlock CB(Condition, BOp->getOperand(0),
-                   BOp->getOperand(1), NULL, TBB, FBB, CurBB);
-      SwitchCases.push_back(CB);
-      return;
+      return DAG.getMergeValues(&Constants[0], Constants.size(),
+                                getCurDebugLoc());
     }
-  }
 
-  // Create a CaseBlock record representing this branch.
-  CaseBlock CB(ISD::SETEQ, Cond, ConstantInt::getTrue(*DAG.getContext()),
-               NULL, TBB, FBB, CurBB);
-  SwitchCases.push_back(CB);
-}
+    if (C->getType()->isStructTy() || C->getType()->isArrayTy()) {
+      assert((isa<ConstantAggregateZero>(C) || isa<UndefValue>(C)) &&
+             "Unknown struct or array constant!");
 
-/// FindMergedConditions - If Cond is an expression like
-void SelectionDAGBuilder::FindMergedConditions(const Value *Cond,
-                                               MachineBasicBlock *TBB,
-                                               MachineBasicBlock *FBB,
-                                               MachineBasicBlock *CurBB,
-                                               MachineBasicBlock *SwitchBB,
-                                               unsigned Opc) {
-  // If this node is not part of the or/and tree, emit it as a branch.
-  const Instruction *BOp = dyn_cast<Instruction>(Cond);
-  if (!BOp || !(isa<BinaryOperator>(BOp) || isa<CmpInst>(BOp)) ||
-      (unsigned)BOp->getOpcode() != Opc || !BOp->hasOneUse() ||
-      BOp->getParent() != CurBB->getBasicBlock() ||
-      !InBlock(BOp->getOperand(0), CurBB->getBasicBlock()) ||
-      !InBlock(BOp->getOperand(1), CurBB->getBasicBlock())) {
-    EmitBranchForMergedCondition(Cond, TBB, FBB, CurBB, SwitchBB);
-    return;
-  }
+      SmallVector<EVT, 4> ValueVTs;
+      ComputeValueVTs(TLI, C->getType(), ValueVTs);
+      unsigned NumElts = ValueVTs.size();
+      if (NumElts == 0)
+        return SDValue(); // empty struct
+      SmallVector<SDValue, 4> Constants(NumElts);
+      for (unsigned i = 0; i != NumElts; ++i) {
+        EVT EltVT = ValueVTs[i];
+        if (isa<UndefValue>(C))
+          Constants[i] = DAG.getUNDEF(EltVT);
+        else if (EltVT.isFloatingPoint())
+          Constants[i] = DAG.getConstantFP(0, EltVT);
+        else
+          Constants[i] = DAG.getConstant(0, EltVT);
+      }
 
-  //  Create TmpBB after CurBB.
-  MachineFunction::iterator BBI = CurBB;
-  MachineFunction &MF = DAG.getMachineFunction();
-  MachineBasicBlock *TmpBB = MF.CreateMachineBasicBlock(CurBB->getBasicBlock());
-  CurBB->getParent()->insert(++BBI, TmpBB);
+      return DAG.getMergeValues(&Constants[0], NumElts,
+                                getCurDebugLoc());
+    }
 
-  if (Opc == Instruction::Or) {
-    // Codegen X | Y as:
-    //   jmp_if_X TBB
-    //   jmp TmpBB
-    // TmpBB:
-    //   jmp_if_Y TBB
-    //   jmp FBB
-    //
+    if (const BlockAddress *BA = dyn_cast<BlockAddress>(C))
+      return DAG.getBlockAddress(BA, VT);
 
-    // Emit the LHS condition.
-    FindMergedConditions(BOp->getOperand(0), TBB, TmpBB, CurBB, SwitchBB, Opc);
+    const VectorType *VecTy = cast<VectorType>(V->getType());
+    unsigned NumElements = VecTy->getNumElements();
 
-    // Emit the RHS condition into TmpBB.
-    FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc);
-  } else {
-    assert(Opc == Instruction::And && "Unknown merge op!");
-    // Codegen X & Y as:
-    //   jmp_if_X TmpBB
-    //   jmp FBB
-    // TmpBB:
-    //   jmp_if_Y TBB
-    //   jmp FBB
-    //
-    //  This requires creation of TmpBB after CurBB.
+    // Now that we know the number and type of the elements, get that number of
+    // elements into the Ops array based on what kind of constant it is.
+    SmallVector<SDValue, 16> Ops;
+    if (const ConstantVector *CP = dyn_cast<ConstantVector>(C)) {
+      for (unsigned i = 0; i != NumElements; ++i)
+        Ops.push_back(getValue(CP->getOperand(i)));
+    } else {
+      assert(isa<ConstantAggregateZero>(C) && "Unknown vector constant!");
+      EVT EltVT = TLI.getValueType(VecTy->getElementType());
 
-    // Emit the LHS condition.
-    FindMergedConditions(BOp->getOperand(0), TmpBB, FBB, CurBB, SwitchBB, Opc);
+      SDValue Op;
+      if (EltVT.isFloatingPoint())
+        Op = DAG.getConstantFP(0, EltVT);
+      else
+        Op = DAG.getConstant(0, EltVT);
+      Ops.assign(NumElements, Op);
+    }
 
-    // Emit the RHS condition into TmpBB.
-    FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc);
+    // Create a BUILD_VECTOR node.
+    return NodeMap[V] = DAG.getNode(ISD::BUILD_VECTOR, getCurDebugLoc(),
+                                    VT, &Ops[0], Ops.size());
   }
-}
 
-/// If the set of cases should be emitted as a series of branches, return true.
-/// If we should emit this as a bunch of and/or'd together conditions, return
-/// false.
-bool
-SelectionDAGBuilder::ShouldEmitAsBranches(const std::vector<CaseBlock> &Cases){
-  if (Cases.size() != 2) return true;
-
-  // If this is two comparisons of the same values or'd or and'd together, they
-  // will get folded into a single comparison, so don't emit two blocks.
-  if ((Cases[0].CmpLHS == Cases[1].CmpLHS &&
-       Cases[0].CmpRHS == Cases[1].CmpRHS) ||
-      (Cases[0].CmpRHS == Cases[1].CmpLHS &&
-       Cases[0].CmpLHS == Cases[1].CmpRHS)) {
-    return false;
+  // If this is a static alloca, generate it as the frameindex instead of
+  // computation.
+  if (const AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
+    DenseMap<const AllocaInst*, int>::iterator SI =
+      FuncInfo.StaticAllocaMap.find(AI);
+    if (SI != FuncInfo.StaticAllocaMap.end())
+      return DAG.getFrameIndex(SI->second, TLI.getPointerTy());
   }
 
-  // Handle: (X != null) | (Y != null) --> (X|Y) != 0
-  // Handle: (X == null) & (Y == null) --> (X|Y) == 0
-  if (Cases[0].CmpRHS == Cases[1].CmpRHS &&
-      Cases[0].CC == Cases[1].CC &&
-      isa<Constant>(Cases[0].CmpRHS) &&
-      cast<Constant>(Cases[0].CmpRHS)->isNullValue()) {
-    if (Cases[0].CC == ISD::SETEQ && Cases[0].TrueBB == Cases[1].ThisBB)
-      return false;
-    if (Cases[0].CC == ISD::SETNE && Cases[0].FalseBB == Cases[1].ThisBB)
-      return false;
-  }
-  
-  return true;
+  unsigned InReg = FuncInfo.ValueMap[V];
+  assert(InReg && "Value not in map!");
+
+  RegsForValue RFV(*DAG.getContext(), TLI, InReg, V->getType());
+  SDValue Chain = DAG.getEntryNode();
+  return RFV.getCopyFromRegs(DAG, FuncInfo, getCurDebugLoc(), Chain, NULL);
 }
 
-void SelectionDAGBuilder::visitBr(const BranchInst &I) {
-  MachineBasicBlock *BrMBB = FuncInfo.MBBMap[I.getParent()];
+/// Get the EVTs and ArgFlags collections that represent the legalized return 
+/// type of the given function.  This does not require a DAG or a return value,
+/// and is suitable for use before any DAGs for the function are constructed.
+static void getReturnInfo(const Type* ReturnType,
+                   Attributes attr, SmallVectorImpl<EVT> &OutVTs,
+                   SmallVectorImpl<ISD::ArgFlagsTy> &OutFlags,
+                   const TargetLowering &TLI,
+                   SmallVectorImpl<uint64_t> *Offsets = 0) {
+  SmallVector<EVT, 4> ValueVTs;
+  ComputeValueVTs(TLI, ReturnType, ValueVTs);
+  unsigned NumValues = ValueVTs.size();
+  if (NumValues == 0) return;
+  unsigned Offset = 0;
 
-  // Update machine-CFG edges.
-  MachineBasicBlock *Succ0MBB = FuncInfo.MBBMap[I.getSuccessor(0)];
+  for (unsigned j = 0, f = NumValues; j != f; ++j) {
+    EVT VT = ValueVTs[j];
+    ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
 
-  // Figure out which block is immediately after the current one.
-  MachineBasicBlock *NextBlock = 0;
-  MachineFunction::iterator BBI = BrMBB;
-  if (++BBI != FuncInfo.MF->end())
-    NextBlock = BBI;
+    if (attr & Attribute::SExt)
+      ExtendKind = ISD::SIGN_EXTEND;
+    else if (attr & Attribute::ZExt)
+      ExtendKind = ISD::ZERO_EXTEND;
 
-  if (I.isUnconditional()) {
-    // Update machine-CFG edges.
-    BrMBB->addSuccessor(Succ0MBB);
+    // FIXME: C calling convention requires the return type to be promoted to
+    // at least 32-bit. But this is not necessary for non-C calling
+    // conventions. The frontend should mark functions whose return values
+    // require promoting with signext or zeroext attributes.
+    if (ExtendKind != ISD::ANY_EXTEND && VT.isInteger()) {
+      EVT MinVT = TLI.getRegisterType(ReturnType->getContext(), MVT::i32);
+      if (VT.bitsLT(MinVT))
+        VT = MinVT;
+    }
 
-    // If this is not a fall-through branch, emit the branch.
-    if (Succ0MBB != NextBlock)
-      DAG.setRoot(DAG.getNode(ISD::BR, getCurDebugLoc(),
-                              MVT::Other, getControlRoot(),
-                              DAG.getBasicBlock(Succ0MBB)));
+    unsigned NumParts = TLI.getNumRegisters(ReturnType->getContext(), VT);
+    EVT PartVT = TLI.getRegisterType(ReturnType->getContext(), VT);
+    unsigned PartSize = TLI.getTargetData()->getTypeAllocSize(
+                        PartVT.getTypeForEVT(ReturnType->getContext()));
 
-    return;
+    // 'inreg' on function refers to return value
+    ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy();
+    if (attr & Attribute::InReg)
+      Flags.setInReg();
+
+    // Propagate extension type if any
+    if (attr & Attribute::SExt)
+      Flags.setSExt();
+    else if (attr & Attribute::ZExt)
+      Flags.setZExt();
+
+    for (unsigned i = 0; i < NumParts; ++i) {
+      OutVTs.push_back(PartVT);
+      OutFlags.push_back(Flags);
+      if (Offsets)
+      {
+        Offsets->push_back(Offset);
+        Offset += PartSize;
+      }
+    }
   }
+}
 
-  // If this condition is one of the special cases we handle, do special stuff
-  // now.
-  const Value *CondVal = I.getCondition();
-  MachineBasicBlock *Succ1MBB = FuncInfo.MBBMap[I.getSuccessor(1)];
+void SelectionDAGBuilder::visitRet(const ReturnInst &I) {
+  SDValue Chain = getControlRoot();
+  SmallVector<ISD::OutputArg, 8> Outs;
 
-  // If this is a series of conditions that are or'd or and'd together, emit
-  // this as a sequence of branches instead of setcc's with and/or operations.
-  // For example, instead of something like:
-  //     cmp A, B
-  //     C = seteq
-  //     cmp D, E
-  //     F = setle
-  //     or C, F
-  //     jnz foo
-  // Emit:
-  //     cmp A, B
-  //     je foo
-  //     cmp D, E
-  //     jle foo
-  //
-  if (const BinaryOperator *BOp = dyn_cast<BinaryOperator>(CondVal)) {
-    if (BOp->hasOneUse() &&
-        (BOp->getOpcode() == Instruction::And ||
-         BOp->getOpcode() == Instruction::Or)) {
-      FindMergedConditions(BOp, Succ0MBB, Succ1MBB, BrMBB, BrMBB,
-                           BOp->getOpcode());
-      // If the compares in later blocks need to use values not currently
-      // exported from this block, export them now.  This block should always
-      // be the first entry.
-      assert(SwitchCases[0].ThisBB == BrMBB && "Unexpected lowering!");
+  if (!FuncInfo.CanLowerReturn) {
+    unsigned DemoteReg = FuncInfo.DemoteRegister;
+    const Function *F = I.getParent()->getParent();
 
-      // Allow some cases to be rejected.
-      if (ShouldEmitAsBranches(SwitchCases)) {
-        for (unsigned i = 1, e = SwitchCases.size(); i != e; ++i) {
-          ExportFromCurrentBlock(SwitchCases[i].CmpLHS);
-          ExportFromCurrentBlock(SwitchCases[i].CmpRHS);
-        }
+    // Emit a store of the return value through the virtual register.
+    // Leave Outs empty so that LowerReturn won't try to load return
+    // registers the usual way.
+    SmallVector<EVT, 1> PtrValueVTs;
+    ComputeValueVTs(TLI, PointerType::getUnqual(F->getReturnType()),
+                    PtrValueVTs);
 
-        // Emit the branch for this block.
-        visitSwitchCase(SwitchCases[0], BrMBB);
-        SwitchCases.erase(SwitchCases.begin());
-        return;
-      }
+    SDValue RetPtr = DAG.getRegister(DemoteReg, PtrValueVTs[0]);
+    SDValue RetOp = getValue(I.getOperand(0));
 
-      // Okay, we decided not to do this, remove any inserted MBB's and clear
-      // SwitchCases.
-      for (unsigned i = 1, e = SwitchCases.size(); i != e; ++i)
-        FuncInfo.MF->erase(SwitchCases[i].ThisBB);
+    SmallVector<EVT, 4> ValueVTs;
+    SmallVector<uint64_t, 4> Offsets;
+    ComputeValueVTs(TLI, I.getOperand(0)->getType(), ValueVTs, &Offsets);
+    unsigned NumValues = ValueVTs.size();
 
-      SwitchCases.clear();
+    SmallVector<SDValue, 4> Chains(NumValues);
+    EVT PtrVT = PtrValueVTs[0];
+    for (unsigned i = 0; i != NumValues; ++i) {
+      SDValue Add = DAG.getNode(ISD::ADD, getCurDebugLoc(), PtrVT, RetPtr,
+                                DAG.getConstant(Offsets[i], PtrVT));
+      Chains[i] =
+        DAG.getStore(Chain, getCurDebugLoc(),
+                     SDValue(RetOp.getNode(), RetOp.getResNo() + i),
+                     Add, NULL, Offsets[i], false, false, 0);
     }
-  }
 
-  // Create a CaseBlock record representing this branch.
-  CaseBlock CB(ISD::SETEQ, CondVal, ConstantInt::getTrue(*DAG.getContext()),
-               NULL, Succ0MBB, Succ1MBB, BrMBB);
+    Chain = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(),
+                        MVT::Other, &Chains[0], NumValues);
+  } else if (I.getNumOperands() != 0) {
+    SmallVector<EVT, 4> ValueVTs;
+    ComputeValueVTs(TLI, I.getOperand(0)->getType(), ValueVTs);
+    unsigned NumValues = ValueVTs.size();
+    if (NumValues) {
+      SDValue RetOp = getValue(I.getOperand(0));
+      for (unsigned j = 0, f = NumValues; j != f; ++j) {
+        EVT VT = ValueVTs[j];
 
-  // Use visitSwitchCase to actually insert the fast branch sequence for this
-  // cond branch.
-  visitSwitchCase(CB, BrMBB);
-}
+        ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
 
-/// visitSwitchCase - Emits the necessary code to represent a single node in
-/// the binary search tree resulting from lowering a switch instruction.
-void SelectionDAGBuilder::visitSwitchCase(CaseBlock &CB,
-                                          MachineBasicBlock *SwitchBB) {
-  SDValue Cond;
-  SDValue CondLHS = getValue(CB.CmpLHS);
-  DebugLoc dl = getCurDebugLoc();
+        const Function *F = I.getParent()->getParent();
+        if (F->paramHasAttr(0, Attribute::SExt))
+          ExtendKind = ISD::SIGN_EXTEND;
+        else if (F->paramHasAttr(0, Attribute::ZExt))
+          ExtendKind = ISD::ZERO_EXTEND;
 
-  // Build the setcc now.
-  if (CB.CmpMHS == NULL) {
-    // Fold "(X == true)" to X and "(X == false)" to !X to
-    // handle common cases produced by branch lowering.
-    if (CB.CmpRHS == ConstantInt::getTrue(*DAG.getContext()) &&
-        CB.CC == ISD::SETEQ)
-      Cond = CondLHS;
-    else if (CB.CmpRHS == ConstantInt::getFalse(*DAG.getContext()) &&
-             CB.CC == ISD::SETEQ) {
-      SDValue True = DAG.getConstant(1, CondLHS.getValueType());
-      Cond = DAG.getNode(ISD::XOR, dl, CondLHS.getValueType(), CondLHS, True);
-    } else
-      Cond = DAG.getSetCC(dl, MVT::i1, CondLHS, getValue(CB.CmpRHS), CB.CC);
-  } else {
-    assert(CB.CC == ISD::SETLE && "Can handle only LE ranges now");
+        // FIXME: C calling convention requires the return type to be promoted
+        // to at least 32-bit. But this is not necessary for non-C calling
+        // conventions. The frontend should mark functions whose return values
+        // require promoting with signext or zeroext attributes.
+        if (ExtendKind != ISD::ANY_EXTEND && VT.isInteger()) {
+          EVT MinVT = TLI.getRegisterType(*DAG.getContext(), MVT::i32);
+          if (VT.bitsLT(MinVT))
+            VT = MinVT;
+        }
 
-    const APInt& Low = cast<ConstantInt>(CB.CmpLHS)->getValue();
-    const APInt& High  = cast<ConstantInt>(CB.CmpRHS)->getValue();
+        unsigned NumParts = TLI.getNumRegisters(*DAG.getContext(), VT);
+        EVT PartVT = TLI.getRegisterType(*DAG.getContext(), VT);
+        SmallVector<SDValue, 4> Parts(NumParts);
+        getCopyToParts(DAG, getCurDebugLoc(),
+                       SDValue(RetOp.getNode(), RetOp.getResNo() + j),
+                       &Parts[0], NumParts, PartVT, ExtendKind);
 
-    SDValue CmpOp = getValue(CB.CmpMHS);
-    EVT VT = CmpOp.getValueType();
+        // 'inreg' on function refers to return value
+        ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy();
+        if (F->paramHasAttr(0, Attribute::InReg))
+          Flags.setInReg();
 
-    if (cast<ConstantInt>(CB.CmpLHS)->isMinValue(true)) {
-      Cond = DAG.getSetCC(dl, MVT::i1, CmpOp, DAG.getConstant(High, VT),
-                          ISD::SETLE);
-    } else {
-      SDValue SUB = DAG.getNode(ISD::SUB, dl,
-                                VT, CmpOp, DAG.getConstant(Low, VT));
-      Cond = DAG.getSetCC(dl, MVT::i1, SUB,
-                          DAG.getConstant(High-Low, VT), ISD::SETULE);
+        // Propagate extension type if any
+        if (F->paramHasAttr(0, Attribute::SExt))
+          Flags.setSExt();
+        else if (F->paramHasAttr(0, Attribute::ZExt))
+          Flags.setZExt();
+
+        for (unsigned i = 0; i < NumParts; ++i)
+          Outs.push_back(ISD::OutputArg(Flags, Parts[i], /*isfixed=*/true));
+      }
     }
   }
 
-  // Update successor info
-  SwitchBB->addSuccessor(CB.TrueBB);
-  SwitchBB->addSuccessor(CB.FalseBB);
+  bool isVarArg = DAG.getMachineFunction().getFunction()->isVarArg();
+  CallingConv::ID CallConv =
+    DAG.getMachineFunction().getFunction()->getCallingConv();
+  Chain = TLI.LowerReturn(Chain, CallConv, isVarArg,
+                          Outs, getCurDebugLoc(), DAG);
 
-  // Set NextBlock to be the MBB immediately after the current one, if any.
-  // This is used to avoid emitting unnecessary branches to the next block.
-  MachineBasicBlock *NextBlock = 0;
-  MachineFunction::iterator BBI = SwitchBB;
-  if (++BBI != FuncInfo.MF->end())
-    NextBlock = BBI;
+  // Verify that the target's LowerReturn behaved as expected.
+  assert(Chain.getNode() && Chain.getValueType() == MVT::Other &&
+         "LowerReturn didn't return a valid chain!");
 
-  // If the lhs block is the next block, invert the condition so that we can
-  // fall through to the lhs instead of the rhs block.
-  if (CB.TrueBB == NextBlock) {
-    std::swap(CB.TrueBB, CB.FalseBB);
-    SDValue True = DAG.getConstant(1, Cond.getValueType());
-    Cond = DAG.getNode(ISD::XOR, dl, Cond.getValueType(), Cond, True);
-  }
+  // Update the DAG with the new chain value resulting from return lowering.
+  DAG.setRoot(Chain);
+}
 
-  SDValue BrCond = DAG.getNode(ISD::BRCOND, dl,
-                               MVT::Other, getControlRoot(), Cond,
-                               DAG.getBasicBlock(CB.TrueBB));
+/// CopyToExportRegsIfNeeded - If the given value has virtual registers
+/// created for it, emit nodes to copy the value into the virtual
+/// registers.
+void SelectionDAGBuilder::CopyToExportRegsIfNeeded(const Value *V) {
+  DenseMap<const Value *, unsigned>::iterator VMI = FuncInfo.ValueMap.find(V);
+  if (VMI != FuncInfo.ValueMap.end()) {
+    assert(!V->use_empty() && "Unused value assigned virtual registers!");
+    CopyValueToVirtualRegister(V, VMI->second);
+  }
+}
 
-  // If the branch was constant folded, fix up the CFG.
-  if (BrCond.getOpcode() == ISD::BR) {
-    SwitchBB->removeSuccessor(CB.FalseBB);
-  } else {
-    // Otherwise, go ahead and insert the false branch.
-    if (BrCond == getControlRoot())
-      SwitchBB->removeSuccessor(CB.TrueBB);
+/// ExportFromCurrentBlock - If this condition isn't known to be exported from
+/// the current basic block, add it to ValueMap now so that we'll get a
+/// CopyTo/FromReg.
+void SelectionDAGBuilder::ExportFromCurrentBlock(const Value *V) {
+  // No need to export constants.
+  if (!isa<Instruction>(V) && !isa<Argument>(V)) return;
 
-    if (CB.FalseBB != NextBlock)
-      BrCond = DAG.getNode(ISD::BR, dl, MVT::Other, BrCond,
-                           DAG.getBasicBlock(CB.FalseBB));
-  }
+  // Already exported?
+  if (FuncInfo.isExportedInst(V)) return;
 
-  DAG.setRoot(BrCond);
+  unsigned Reg = FuncInfo.InitializeRegForValue(V);
+  CopyValueToVirtualRegister(V, Reg);
 }
 
-/// visitJumpTable - Emit JumpTable node in the current MBB
-void SelectionDAGBuilder::visitJumpTable(JumpTable &JT) {
-  // Emit the code for the jump table
-  assert(JT.Reg != -1U && "Should lower JT Header first!");
-  EVT PTy = TLI.getPointerTy();
-  SDValue Index = DAG.getCopyFromReg(getControlRoot(), getCurDebugLoc(),
-                                     JT.Reg, PTy);
-  SDValue Table = DAG.getJumpTable(JT.JTI, PTy);
-  SDValue BrJumpTable = DAG.getNode(ISD::BR_JT, getCurDebugLoc(),
-                                    MVT::Other, Index.getValue(1),
-                                    Table, Index);
-  DAG.setRoot(BrJumpTable);
-}
+bool SelectionDAGBuilder::isExportableFromCurrentBlock(const Value *V,
+                                                     const BasicBlock *FromBB) {
+  // The operands of the setcc have to be in this block.  We don't know
+  // how to export them from some other block.
+  if (const Instruction *VI = dyn_cast<Instruction>(V)) {
+    // Can export from current BB.
+    if (VI->getParent() == FromBB)
+      return true;
 
-/// visitJumpTableHeader - This function emits necessary code to produce index
-/// in the JumpTable from switch case.
-void SelectionDAGBuilder::visitJumpTableHeader(JumpTable &JT,
-                                               JumpTableHeader &JTH,
-                                               MachineBasicBlock *SwitchBB) {
-  // Subtract the lowest switch case value from the value being switched on and
-  // conditional branch to default mbb if the result is greater than the
-  // difference between smallest and largest cases.
-  SDValue SwitchOp = getValue(JTH.SValue);
-  EVT VT = SwitchOp.getValueType();
-  SDValue Sub = DAG.getNode(ISD::SUB, getCurDebugLoc(), VT, SwitchOp,
-                            DAG.getConstant(JTH.First, VT));
+    // Is already exported, noop.
+    return FuncInfo.isExportedInst(V);
+  }
 
-  // The SDNode we just created, which holds the value being switched on minus
-  // the smallest case value, needs to be copied to a virtual register so it
-  // can be used as an index into the jump table in a subsequent basic block.
-  // This value may be smaller or larger than the target's pointer type, and
-  // therefore require extension or truncating.
-  SwitchOp = DAG.getZExtOrTrunc(Sub, getCurDebugLoc(), TLI.getPointerTy());
+  // If this is an argument, we can export it if the BB is the entry block or
+  // if it is already exported.
+  if (isa<Argument>(V)) {
+    if (FromBB == &FromBB->getParent()->getEntryBlock())
+      return true;
 
-  unsigned JumpTableReg = FuncInfo.MakeReg(TLI.getPointerTy());
-  SDValue CopyTo = DAG.getCopyToReg(getControlRoot(), getCurDebugLoc(),
-                                    JumpTableReg, SwitchOp);
-  JT.Reg = JumpTableReg;
+    // Otherwise, can only export this if it is already exported.
+    return FuncInfo.isExportedInst(V);
+  }
 
-  // Emit the range check for the jump table, and branch to the default block
-  // for the switch statement if the value being switched on exceeds the largest
-  // case in the switch.
-  SDValue CMP = DAG.getSetCC(getCurDebugLoc(),
-                             TLI.getSetCCResultType(Sub.getValueType()), Sub,
-                             DAG.getConstant(JTH.Last-JTH.First,VT),
-                             ISD::SETUGT);
+  // Otherwise, constants can always be exported.
+  return true;
+}
 
-  // Set NextBlock to be the MBB immediately after the current one, if any.
-  // This is used to avoid emitting unnecessary branches to the next block.
-  MachineBasicBlock *NextBlock = 0;
-  MachineFunction::iterator BBI = SwitchBB;
+static bool InBlock(const Value *V, const BasicBlock *BB) {
+  if (const Instruction *I = dyn_cast<Instruction>(V))
+    return I->getParent() == BB;
+  return true;
+}
 
-  if (++BBI != FuncInfo.MF->end())
-    NextBlock = BBI;
+/// EmitBranchForMergedCondition - Helper method for FindMergedConditions.
+/// This function emits a branch and is used at the leaves of an OR or an
+/// AND operator tree.
+///
+void
+SelectionDAGBuilder::EmitBranchForMergedCondition(const Value *Cond,
+                                                  MachineBasicBlock *TBB,
+                                                  MachineBasicBlock *FBB,
+                                                  MachineBasicBlock *CurBB,
+                                                  MachineBasicBlock *SwitchBB) {
+  const BasicBlock *BB = CurBB->getBasicBlock();
 
-  SDValue BrCond = DAG.getNode(ISD::BRCOND, getCurDebugLoc(),
-                               MVT::Other, CopyTo, CMP,
-                               DAG.getBasicBlock(JT.Default));
+  // If the leaf of the tree is a comparison, merge the condition into
+  // the caseblock.
+  if (const CmpInst *BOp = dyn_cast<CmpInst>(Cond)) {
+    // The operands of the cmp have to be in this block.  We don't know
+    // how to export them from some other block.  If this is the first block
+    // of the sequence, no exporting is needed.
+    if (CurBB == SwitchBB ||
+        (isExportableFromCurrentBlock(BOp->getOperand(0), BB) &&
+         isExportableFromCurrentBlock(BOp->getOperand(1), BB))) {
+      ISD::CondCode Condition;
+      if (const ICmpInst *IC = dyn_cast<ICmpInst>(Cond)) {
+        Condition = getICmpCondCode(IC->getPredicate());
+      } else if (const FCmpInst *FC = dyn_cast<FCmpInst>(Cond)) {
+        Condition = getFCmpCondCode(FC->getPredicate());
+      } else {
+        Condition = ISD::SETEQ; // silence warning.
+        llvm_unreachable("Unknown compare instruction");
+      }
 
-  if (JT.MBB != NextBlock)
-    BrCond = DAG.getNode(ISD::BR, getCurDebugLoc(), MVT::Other, BrCond,
-                         DAG.getBasicBlock(JT.MBB));
+      CaseBlock CB(Condition, BOp->getOperand(0),
+                   BOp->getOperand(1), NULL, TBB, FBB, CurBB);
+      SwitchCases.push_back(CB);
+      return;
+    }
+  }
 
-  DAG.setRoot(BrCond);
+  // Create a CaseBlock record representing this branch.
+  CaseBlock CB(ISD::SETEQ, Cond, ConstantInt::getTrue(*DAG.getContext()),
+               NULL, TBB, FBB, CurBB);
+  SwitchCases.push_back(CB);
 }
 
-/// visitBitTestHeader - This function emits necessary code to produce value
-/// suitable for "bit tests"
-void SelectionDAGBuilder::visitBitTestHeader(BitTestBlock &B,
-                                             MachineBasicBlock *SwitchBB) {
-  // Subtract the minimum value
-  SDValue SwitchOp = getValue(B.SValue);
-  EVT VT = SwitchOp.getValueType();
-  SDValue Sub = DAG.getNode(ISD::SUB, getCurDebugLoc(), VT, SwitchOp,
-                            DAG.getConstant(B.First, VT));
+/// FindMergedConditions - If Cond is an expression like
+void SelectionDAGBuilder::FindMergedConditions(const Value *Cond,
+                                               MachineBasicBlock *TBB,
+                                               MachineBasicBlock *FBB,
+                                               MachineBasicBlock *CurBB,
+                                               MachineBasicBlock *SwitchBB,
+                                               unsigned Opc) {
+  // If this node is not part of the or/and tree, emit it as a branch.
+  const Instruction *BOp = dyn_cast<Instruction>(Cond);
+  if (!BOp || !(isa<BinaryOperator>(BOp) || isa<CmpInst>(BOp)) ||
+      (unsigned)BOp->getOpcode() != Opc || !BOp->hasOneUse() ||
+      BOp->getParent() != CurBB->getBasicBlock() ||
+      !InBlock(BOp->getOperand(0), CurBB->getBasicBlock()) ||
+      !InBlock(BOp->getOperand(1), CurBB->getBasicBlock())) {
+    EmitBranchForMergedCondition(Cond, TBB, FBB, CurBB, SwitchBB);
+    return;
+  }
 
-  // Check range
-  SDValue RangeCmp = DAG.getSetCC(getCurDebugLoc(),
-                                  TLI.getSetCCResultType(Sub.getValueType()),
-                                  Sub, DAG.getConstant(B.Range, VT),
-                                  ISD::SETUGT);
+  //  Create TmpBB after CurBB.
+  MachineFunction::iterator BBI = CurBB;
+  MachineFunction &MF = DAG.getMachineFunction();
+  MachineBasicBlock *TmpBB = MF.CreateMachineBasicBlock(CurBB->getBasicBlock());
+  CurBB->getParent()->insert(++BBI, TmpBB);
 
-  SDValue ShiftOp = DAG.getZExtOrTrunc(Sub, getCurDebugLoc(),
-                                       TLI.getPointerTy());
+  if (Opc == Instruction::Or) {
+    // Codegen X | Y as:
+    //   jmp_if_X TBB
+    //   jmp TmpBB
+    // TmpBB:
+    //   jmp_if_Y TBB
+    //   jmp FBB
+    //
 
-  B.Reg = FuncInfo.MakeReg(TLI.getPointerTy());
-  SDValue CopyTo = DAG.getCopyToReg(getControlRoot(), getCurDebugLoc(),
-                                    B.Reg, ShiftOp);
+    // Emit the LHS condition.
+    FindMergedConditions(BOp->getOperand(0), TBB, TmpBB, CurBB, SwitchBB, Opc);
 
-  // Set NextBlock to be the MBB immediately after the current one, if any.
-  // This is used to avoid emitting unnecessary branches to the next block.
-  MachineBasicBlock *NextBlock = 0;
-  MachineFunction::iterator BBI = SwitchBB;
-  if (++BBI != FuncInfo.MF->end())
-    NextBlock = BBI;
+    // Emit the RHS condition into TmpBB.
+    FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc);
+  } else {
+    assert(Opc == Instruction::And && "Unknown merge op!");
+    // Codegen X & Y as:
+    //   jmp_if_X TmpBB
+    //   jmp FBB
+    // TmpBB:
+    //   jmp_if_Y TBB
+    //   jmp FBB
+    //
+    //  This requires creation of TmpBB after CurBB.
 
-  MachineBasicBlock* MBB = B.Cases[0].ThisBB;
+    // Emit the LHS condition.
+    FindMergedConditions(BOp->getOperand(0), TmpBB, FBB, CurBB, SwitchBB, Opc);
 
-  SwitchBB->addSuccessor(B.Default);
-  SwitchBB->addSuccessor(MBB);
+    // Emit the RHS condition into TmpBB.
+    FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc);
+  }
+}
 
-  SDValue BrRange = DAG.getNode(ISD::BRCOND, getCurDebugLoc(),
-                                MVT::Other, CopyTo, RangeCmp,
-                                DAG.getBasicBlock(B.Default));
+/// If the set of cases should be emitted as a series of branches, return true.
+/// If we should emit this as a bunch of and/or'd together conditions, return
+/// false.
+bool
+SelectionDAGBuilder::ShouldEmitAsBranches(const std::vector<CaseBlock> &Cases){
+  if (Cases.size() != 2) return true;
 
-  if (MBB != NextBlock)
-    BrRange = DAG.getNode(ISD::BR, getCurDebugLoc(), MVT::Other, CopyTo,
-                          DAG.getBasicBlock(MBB));
+  // If this is two comparisons of the same values or'd or and'd together, they
+  // will get folded into a single comparison, so don't emit two blocks.
+  if ((Cases[0].CmpLHS == Cases[1].CmpLHS &&
+       Cases[0].CmpRHS == Cases[1].CmpRHS) ||
+      (Cases[0].CmpRHS == Cases[1].CmpLHS &&
+       Cases[0].CmpLHS == Cases[1].CmpRHS)) {
+    return false;
+  }
 
-  DAG.setRoot(BrRange);
+  // Handle: (X != null) | (Y != null) --> (X|Y) != 0
+  // Handle: (X == null) & (Y == null) --> (X|Y) == 0
+  if (Cases[0].CmpRHS == Cases[1].CmpRHS &&
+      Cases[0].CC == Cases[1].CC &&
+      isa<Constant>(Cases[0].CmpRHS) &&
+      cast<Constant>(Cases[0].CmpRHS)->isNullValue()) {
+    if (Cases[0].CC == ISD::SETEQ && Cases[0].TrueBB == Cases[1].ThisBB)
+      return false;
+    if (Cases[0].CC == ISD::SETNE && Cases[0].FalseBB == Cases[1].ThisBB)
+      return false;
+  }
+  
+  return true;
 }
 
-/// visitBitTestCase - this function produces one "bit test"
-void SelectionDAGBuilder::visitBitTestCase(MachineBasicBlock* NextMBB,
-                                           unsigned Reg,
-                                           BitTestCase &B,
-                                           MachineBasicBlock *SwitchBB) {
-  // Make desired shift
-  SDValue ShiftOp = DAG.getCopyFromReg(getControlRoot(), getCurDebugLoc(), Reg,
-                                       TLI.getPointerTy());
-  SDValue SwitchVal = DAG.getNode(ISD::SHL, getCurDebugLoc(),
-                                  TLI.getPointerTy(),
-                                  DAG.getConstant(1, TLI.getPointerTy()),
-                                  ShiftOp);
-
-  // Emit bit tests and jumps
-  SDValue AndOp = DAG.getNode(ISD::AND, getCurDebugLoc(),
-                              TLI.getPointerTy(), SwitchVal,
-                              DAG.getConstant(B.Mask, TLI.getPointerTy()));
-  SDValue AndCmp = DAG.getSetCC(getCurDebugLoc(),
-                                TLI.getSetCCResultType(AndOp.getValueType()),
-                                AndOp, DAG.getConstant(0, TLI.getPointerTy()),
-                                ISD::SETNE);
-
-  SwitchBB->addSuccessor(B.TargetBB);
-  SwitchBB->addSuccessor(NextMBB);
+void SelectionDAGBuilder::visitBr(const BranchInst &I) {
+  MachineBasicBlock *BrMBB = FuncInfo.MBBMap[I.getParent()];
 
-  SDValue BrAnd = DAG.getNode(ISD::BRCOND, getCurDebugLoc(),
-                              MVT::Other, getControlRoot(),
-                              AndCmp, DAG.getBasicBlock(B.TargetBB));
+  // Update machine-CFG edges.
+  MachineBasicBlock *Succ0MBB = FuncInfo.MBBMap[I.getSuccessor(0)];
 
-  // Set NextBlock to be the MBB immediately after the current one, if any.
-  // This is used to avoid emitting unnecessary branches to the next block.
+  // Figure out which block is immediately after the current one.
   MachineBasicBlock *NextBlock = 0;
-  MachineFunction::iterator BBI = SwitchBB;
+  MachineFunction::iterator BBI = BrMBB;
   if (++BBI != FuncInfo.MF->end())
     NextBlock = BBI;
 
-  if (NextMBB != NextBlock)
-    BrAnd = DAG.getNode(ISD::BR, getCurDebugLoc(), MVT::Other, BrAnd,
-                        DAG.getBasicBlock(NextMBB));
-
-  DAG.setRoot(BrAnd);
-}
-
-void SelectionDAGBuilder::visitInvoke(const InvokeInst &I) {
-  MachineBasicBlock *InvokeMBB = FuncInfo.MBBMap[I.getParent()];
+  if (I.isUnconditional()) {
+    // Update machine-CFG edges.
+    BrMBB->addSuccessor(Succ0MBB);
 
-  // Retrieve successors.
-  MachineBasicBlock *Return = FuncInfo.MBBMap[I.getSuccessor(0)];
-  MachineBasicBlock *LandingPad = FuncInfo.MBBMap[I.getSuccessor(1)];
+    // If this is not a fall-through branch, emit the branch.
+    if (Succ0MBB != NextBlock)
+      DAG.setRoot(DAG.getNode(ISD::BR, getCurDebugLoc(),
+                              MVT::Other, getControlRoot(),
+                              DAG.getBasicBlock(Succ0MBB)));
 
-  const Value *Callee(I.getCalledValue());
-  if (isa<InlineAsm>(Callee))
-    visitInlineAsm(&I);
-  else
-    LowerCallTo(&I, getValue(Callee), false, LandingPad);
+    return;
+  }
 
-  // If the value of the invoke is used outside of its defining block, make it
-  // available as a virtual register.
-  CopyToExportRegsIfNeeded(&I);
+  // If this condition is one of the special cases we handle, do special stuff
+  // now.
+  const Value *CondVal = I.getCondition();
+  MachineBasicBlock *Succ1MBB = FuncInfo.MBBMap[I.getSuccessor(1)];
 
-  // Update successor info
-  InvokeMBB->addSuccessor(Return);
-  InvokeMBB->addSuccessor(LandingPad);
+  // If this is a series of conditions that are or'd or and'd together, emit
+  // this as a sequence of branches instead of setcc's with and/or operations.
+  // For example, instead of something like:
+  //     cmp A, B
+  //     C = seteq
+  //     cmp D, E
+  //     F = setle
+  //     or C, F
+  //     jnz foo
+  // Emit:
+  //     cmp A, B
+  //     je foo
+  //     cmp D, E
+  //     jle foo
+  //
+  if (const BinaryOperator *BOp = dyn_cast<BinaryOperator>(CondVal)) {
+    if (BOp->hasOneUse() &&
+        (BOp->getOpcode() == Instruction::And ||
+         BOp->getOpcode() == Instruction::Or)) {
+      FindMergedConditions(BOp, Succ0MBB, Succ1MBB, BrMBB, BrMBB,
+                           BOp->getOpcode());
+      // If the compares in later blocks need to use values not currently
+      // exported from this block, export them now.  This block should always
+      // be the first entry.
+      assert(SwitchCases[0].ThisBB == BrMBB && "Unexpected lowering!");
 
-  // Drop into normal successor.
-  DAG.setRoot(DAG.getNode(ISD::BR, getCurDebugLoc(),
-                          MVT::Other, getControlRoot(),
-                          DAG.getBasicBlock(Return)));
-}
+      // Allow some cases to be rejected.
+      if (ShouldEmitAsBranches(SwitchCases)) {
+        for (unsigned i = 1, e = SwitchCases.size(); i != e; ++i) {
+          ExportFromCurrentBlock(SwitchCases[i].CmpLHS);
+          ExportFromCurrentBlock(SwitchCases[i].CmpRHS);
+        }
 
-void SelectionDAGBuilder::visitUnwind(const UnwindInst &I) {
-}
+        // Emit the branch for this block.
+        visitSwitchCase(SwitchCases[0], BrMBB);
+        SwitchCases.erase(SwitchCases.begin());
+        return;
+      }
 
-/// handleSmallSwitchCaseRange - Emit a series of specific tests (suitable for
-/// small case ranges).
-bool SelectionDAGBuilder::handleSmallSwitchRange(CaseRec& CR,
-                                                 CaseRecVector& WorkList,
-                                                 const Value* SV,
-                                                 MachineBasicBlock *Default,
-                                                 MachineBasicBlock *SwitchBB) {
-  Case& BackCase  = *(CR.Range.second-1);
+      // Okay, we decided not to do this, remove any inserted MBB's and clear
+      // SwitchCases.
+      for (unsigned i = 1, e = SwitchCases.size(); i != e; ++i)
+        FuncInfo.MF->erase(SwitchCases[i].ThisBB);
 
-  // Size is the number of Cases represented by this range.
-  size_t Size = CR.Range.second - CR.Range.first;
-  if (Size > 3)
-    return false;
+      SwitchCases.clear();
+    }
+  }
 
-  // Get the MachineFunction which holds the current MBB.  This is used when
-  // inserting any additional MBBs necessary to represent the switch.
-  MachineFunction *CurMF = FuncInfo.MF;
+  // Create a CaseBlock record representing this branch.
+  CaseBlock CB(ISD::SETEQ, CondVal, ConstantInt::getTrue(*DAG.getContext()),
+               NULL, Succ0MBB, Succ1MBB, BrMBB);
 
-  // Figure out which block is immediately after the current one.
-  MachineBasicBlock *NextBlock = 0;
-  MachineFunction::iterator BBI = CR.CaseBB;
+  // Use visitSwitchCase to actually insert the fast branch sequence for this
+  // cond branch.
+  visitSwitchCase(CB, BrMBB);
+}
 
-  if (++BBI != FuncInfo.MF->end())
-    NextBlock = BBI;
+/// visitSwitchCase - Emits the necessary code to represent a single node in
+/// the binary search tree resulting from lowering a switch instruction.
+void SelectionDAGBuilder::visitSwitchCase(CaseBlock &CB,
+                                          MachineBasicBlock *SwitchBB) {
+  SDValue Cond;
+  SDValue CondLHS = getValue(CB.CmpLHS);
+  DebugLoc dl = getCurDebugLoc();
 
-  // TODO: If any two of the cases has the same destination, and if one value
-  // is the same as the other, but has one bit unset that the other has set,
-  // use bit manipulation to do two compares at once.  For example:
-  // "if (X == 6 || X == 4)" -> "if ((X|2) == 6)"
+  // Build the setcc now.
+  if (CB.CmpMHS == NULL) {
+    // Fold "(X == true)" to X and "(X == false)" to !X to
+    // handle common cases produced by branch lowering.
+    if (CB.CmpRHS == ConstantInt::getTrue(*DAG.getContext()) &&
+        CB.CC == ISD::SETEQ)
+      Cond = CondLHS;
+    else if (CB.CmpRHS == ConstantInt::getFalse(*DAG.getContext()) &&
+             CB.CC == ISD::SETEQ) {
+      SDValue True = DAG.getConstant(1, CondLHS.getValueType());
+      Cond = DAG.getNode(ISD::XOR, dl, CondLHS.getValueType(), CondLHS, True);
+    } else
+      Cond = DAG.getSetCC(dl, MVT::i1, CondLHS, getValue(CB.CmpRHS), CB.CC);
+  } else {
+    assert(CB.CC == ISD::SETLE && "Can handle only LE ranges now");
 
-  // Rearrange the case blocks so that the last one falls through if possible.
-  if (NextBlock && Default != NextBlock && BackCase.BB != NextBlock) {
-    // The last case block won't fall through into 'NextBlock' if we emit the
-    // branches in this order.  See if rearranging a case value would help.
-    for (CaseItr I = CR.Range.first, E = CR.Range.second-1; I != E; ++I) {
-      if (I->BB == NextBlock) {
-        std::swap(*I, BackCase);
-        break;
-      }
-    }
-  }
+    const APInt& Low = cast<ConstantInt>(CB.CmpLHS)->getValue();
+    const APInt& High  = cast<ConstantInt>(CB.CmpRHS)->getValue();
 
-  // Create a CaseBlock record representing a conditional branch to
-  // the Case's target mbb if the value being switched on SV is equal
-  // to C.
-  MachineBasicBlock *CurBlock = CR.CaseBB;
-  for (CaseItr I = CR.Range.first, E = CR.Range.second; I != E; ++I) {
-    MachineBasicBlock *FallThrough;
-    if (I != E-1) {
-      FallThrough = CurMF->CreateMachineBasicBlock(CurBlock->getBasicBlock());
-      CurMF->insert(BBI, FallThrough);
+    SDValue CmpOp = getValue(CB.CmpMHS);
+    EVT VT = CmpOp.getValueType();
 
-      // Put SV in a virtual register to make it available from the new blocks.
-      ExportFromCurrentBlock(SV);
+    if (cast<ConstantInt>(CB.CmpLHS)->isMinValue(true)) {
+      Cond = DAG.getSetCC(dl, MVT::i1, CmpOp, DAG.getConstant(High, VT),
+                          ISD::SETLE);
     } else {
-      // If the last case doesn't match, go to the default block.
-      FallThrough = Default;
+      SDValue SUB = DAG.getNode(ISD::SUB, dl,
+                                VT, CmpOp, DAG.getConstant(Low, VT));
+      Cond = DAG.getSetCC(dl, MVT::i1, SUB,
+                          DAG.getConstant(High-Low, VT), ISD::SETULE);
     }
+  }
 
-    const Value *RHS, *LHS, *MHS;
-    ISD::CondCode CC;
-    if (I->High == I->Low) {
-      // This is just small small case range :) containing exactly 1 case
-      CC = ISD::SETEQ;
-      LHS = SV; RHS = I->High; MHS = NULL;
-    } else {
-      CC = ISD::SETLE;
-      LHS = I->Low; MHS = SV; RHS = I->High;
-    }
-    CaseBlock CB(CC, LHS, RHS, MHS, I->BB, FallThrough, CurBlock);
+  // Update successor info
+  SwitchBB->addSuccessor(CB.TrueBB);
+  SwitchBB->addSuccessor(CB.FalseBB);
 
-    // If emitting the first comparison, just call visitSwitchCase to emit the
-    // code into the current block.  Otherwise, push the CaseBlock onto the
-    // vector to be later processed by SDISel, and insert the node's MBB
-    // before the next MBB.
-    if (CurBlock == SwitchBB)
-      visitSwitchCase(CB, SwitchBB);
-    else
-      SwitchCases.push_back(CB);
+  // Set NextBlock to be the MBB immediately after the current one, if any.
+  // This is used to avoid emitting unnecessary branches to the next block.
+  MachineBasicBlock *NextBlock = 0;
+  MachineFunction::iterator BBI = SwitchBB;
+  if (++BBI != FuncInfo.MF->end())
+    NextBlock = BBI;
 
-    CurBlock = FallThrough;
+  // If the lhs block is the next block, invert the condition so that we can
+  // fall through to the lhs instead of the rhs block.
+  if (CB.TrueBB == NextBlock) {
+    std::swap(CB.TrueBB, CB.FalseBB);
+    SDValue True = DAG.getConstant(1, Cond.getValueType());
+    Cond = DAG.getNode(ISD::XOR, dl, Cond.getValueType(), Cond, True);
   }
 
-  return true;
-}
-
-static inline bool areJTsAllowed(const TargetLowering &TLI) {
-  return !DisableJumpTables &&
-          (TLI.isOperationLegalOrCustom(ISD::BR_JT, MVT::Other) ||
-           TLI.isOperationLegalOrCustom(ISD::BRIND, MVT::Other));
-}
+  SDValue BrCond = DAG.getNode(ISD::BRCOND, dl,
+                               MVT::Other, getControlRoot(), Cond,
+                               DAG.getBasicBlock(CB.TrueBB));
 
-static APInt ComputeRange(const APInt &First, const APInt &Last) {
-  APInt LastExt(Last), FirstExt(First);
-  uint32_t BitWidth = std::max(Last.getBitWidth(), First.getBitWidth()) + 1;
-  LastExt.sext(BitWidth); FirstExt.sext(BitWidth);
-  return (LastExt - FirstExt + 1ULL);
+  // If the branch was constant folded, fix up the CFG.
+  if (BrCond.getOpcode() == ISD::BR) {
+    SwitchBB->removeSuccessor(CB.FalseBB);
+  } else {
+    // Otherwise, go ahead and insert the false branch.
+    if (BrCond == getControlRoot())
+      SwitchBB->removeSuccessor(CB.TrueBB);
+
+    if (CB.FalseBB != NextBlock)
+      BrCond = DAG.getNode(ISD::BR, dl, MVT::Other, BrCond,
+                           DAG.getBasicBlock(CB.FalseBB));
+  }
+
+  DAG.setRoot(BrCond);
 }
 
-/// handleJTSwitchCase - Emit jumptable for current switch case range
-bool SelectionDAGBuilder::handleJTSwitchCase(CaseRec& CR,
-                                             CaseRecVector& WorkList,
-                                             const Value* SV,
-                                             MachineBasicBlock* Default,
-                                             MachineBasicBlock *SwitchBB) {
-  Case& FrontCase = *CR.Range.first;
-  Case& BackCase  = *(CR.Range.second-1);
+/// visitJumpTable - Emit JumpTable node in the current MBB
+void SelectionDAGBuilder::visitJumpTable(JumpTable &JT) {
+  // Emit the code for the jump table
+  assert(JT.Reg != -1U && "Should lower JT Header first!");
+  EVT PTy = TLI.getPointerTy();
+  SDValue Index = DAG.getCopyFromReg(getControlRoot(), getCurDebugLoc(),
+                                     JT.Reg, PTy);
+  SDValue Table = DAG.getJumpTable(JT.JTI, PTy);
+  SDValue BrJumpTable = DAG.getNode(ISD::BR_JT, getCurDebugLoc(),
+                                    MVT::Other, Index.getValue(1),
+                                    Table, Index);
+  DAG.setRoot(BrJumpTable);
+}
 
-  const APInt &First = cast<ConstantInt>(FrontCase.Low)->getValue();
-  const APInt &Last  = cast<ConstantInt>(BackCase.High)->getValue();
+/// visitJumpTableHeader - This function emits necessary code to produce index
+/// in the JumpTable from switch case.
+void SelectionDAGBuilder::visitJumpTableHeader(JumpTable &JT,
+                                               JumpTableHeader &JTH,
+                                               MachineBasicBlock *SwitchBB) {
+  // Subtract the lowest switch case value from the value being switched on and
+  // conditional branch to default mbb if the result is greater than the
+  // difference between smallest and largest cases.
+  SDValue SwitchOp = getValue(JTH.SValue);
+  EVT VT = SwitchOp.getValueType();
+  SDValue Sub = DAG.getNode(ISD::SUB, getCurDebugLoc(), VT, SwitchOp,
+                            DAG.getConstant(JTH.First, VT));
 
-  APInt TSize(First.getBitWidth(), 0);
-  for (CaseItr I = CR.Range.first, E = CR.Range.second;
-       I!=E; ++I)
-    TSize += I->size();
+  // The SDNode we just created, which holds the value being switched on minus
+  // the smallest case value, needs to be copied to a virtual register so it
+  // can be used as an index into the jump table in a subsequent basic block.
+  // This value may be smaller or larger than the target's pointer type, and
+  // therefore require extension or truncating.
+  SwitchOp = DAG.getZExtOrTrunc(Sub, getCurDebugLoc(), TLI.getPointerTy());
 
-  if (!areJTsAllowed(TLI) || TSize.ult(4))
-    return false;
+  unsigned JumpTableReg = FuncInfo.MakeReg(TLI.getPointerTy());
+  SDValue CopyTo = DAG.getCopyToReg(getControlRoot(), getCurDebugLoc(),
+                                    JumpTableReg, SwitchOp);
+  JT.Reg = JumpTableReg;
 
-  APInt Range = ComputeRange(First, Last);
-  double Density = TSize.roundToDouble() / Range.roundToDouble();
-  if (Density < 0.4)
-    return false;
+  // Emit the range check for the jump table, and branch to the default block
+  // for the switch statement if the value being switched on exceeds the largest
+  // case in the switch.
+  SDValue CMP = DAG.getSetCC(getCurDebugLoc(),
+                             TLI.getSetCCResultType(Sub.getValueType()), Sub,
+                             DAG.getConstant(JTH.Last-JTH.First,VT),
+                             ISD::SETUGT);
 
-  DEBUG(dbgs() << "Lowering jump table\n"
-               << "First entry: " << First << ". Last entry: " << Last << '\n'
-               << "Range: " << Range
-               << "Size: " << TSize << ". Density: " << Density << "\n\n");
+  // Set NextBlock to be the MBB immediately after the current one, if any.
+  // This is used to avoid emitting unnecessary branches to the next block.
+  MachineBasicBlock *NextBlock = 0;
+  MachineFunction::iterator BBI = SwitchBB;
 
-  // Get the MachineFunction which holds the current MBB.  This is used when
-  // inserting any additional MBBs necessary to represent the switch.
-  MachineFunction *CurMF = FuncInfo.MF;
+  if (++BBI != FuncInfo.MF->end())
+    NextBlock = BBI;
 
-  // Figure out which block is immediately after the current one.
-  MachineFunction::iterator BBI = CR.CaseBB;
-  ++BBI;
+  SDValue BrCond = DAG.getNode(ISD::BRCOND, getCurDebugLoc(),
+                               MVT::Other, CopyTo, CMP,
+                               DAG.getBasicBlock(JT.Default));
 
-  const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
+  if (JT.MBB != NextBlock)
+    BrCond = DAG.getNode(ISD::BR, getCurDebugLoc(), MVT::Other, BrCond,
+                         DAG.getBasicBlock(JT.MBB));
 
-  // Create a new basic block to hold the code for loading the address
-  // of the jump table, and jumping to it.  Update successor information;
-  // we will either branch to the default case for the switch, or the jump
-  // table.
-  MachineBasicBlock *JumpTableBB = CurMF->CreateMachineBasicBlock(LLVMBB);
-  CurMF->insert(BBI, JumpTableBB);
-  CR.CaseBB->addSuccessor(Default);
-  CR.CaseBB->addSuccessor(JumpTableBB);
+  DAG.setRoot(BrCond);
+}
 
-  // Build a vector of destination BBs, corresponding to each target
-  // of the jump table. If the value of the jump table slot corresponds to
-  // a case statement, push the case's BB onto the vector, otherwise, push
-  // the default BB.
-  std::vector<MachineBasicBlock*> DestBBs;
-  APInt TEI = First;
-  for (CaseItr I = CR.Range.first, E = CR.Range.second; I != E; ++TEI) {
-    const APInt &Low = cast<ConstantInt>(I->Low)->getValue();
-    const APInt &High = cast<ConstantInt>(I->High)->getValue();
+/// visitBitTestHeader - This function emits necessary code to produce value
+/// suitable for "bit tests"
+void SelectionDAGBuilder::visitBitTestHeader(BitTestBlock &B,
+                                             MachineBasicBlock *SwitchBB) {
+  // Subtract the minimum value
+  SDValue SwitchOp = getValue(B.SValue);
+  EVT VT = SwitchOp.getValueType();
+  SDValue Sub = DAG.getNode(ISD::SUB, getCurDebugLoc(), VT, SwitchOp,
+                            DAG.getConstant(B.First, VT));
 
-    if (Low.sle(TEI) && TEI.sle(High)) {
-      DestBBs.push_back(I->BB);
-      if (TEI==High)
-        ++I;
-    } else {
-      DestBBs.push_back(Default);
-    }
-  }
+  // Check range
+  SDValue RangeCmp = DAG.getSetCC(getCurDebugLoc(),
+                                  TLI.getSetCCResultType(Sub.getValueType()),
+                                  Sub, DAG.getConstant(B.Range, VT),
+                                  ISD::SETUGT);
 
-  // Update successor info. Add one edge to each unique successor.
-  BitVector SuccsHandled(CR.CaseBB->getParent()->getNumBlockIDs());
-  for (std::vector<MachineBasicBlock*>::iterator I = DestBBs.begin(),
-         E = DestBBs.end(); I != E; ++I) {
-    if (!SuccsHandled[(*I)->getNumber()]) {
-      SuccsHandled[(*I)->getNumber()] = true;
-      JumpTableBB->addSuccessor(*I);
-    }
-  }
+  SDValue ShiftOp = DAG.getZExtOrTrunc(Sub, getCurDebugLoc(),
+                                       TLI.getPointerTy());
 
-  // Create a jump table index for this jump table.
-  unsigned JTEncoding = TLI.getJumpTableEncoding();
-  unsigned JTI = CurMF->getOrCreateJumpTableInfo(JTEncoding)
-                       ->createJumpTableIndex(DestBBs);
+  B.Reg = FuncInfo.MakeReg(TLI.getPointerTy());
+  SDValue CopyTo = DAG.getCopyToReg(getControlRoot(), getCurDebugLoc(),
+                                    B.Reg, ShiftOp);
 
-  // Set the jump table information so that we can codegen it as a second
-  // MachineBasicBlock
-  JumpTable JT(-1U, JTI, JumpTableBB, Default);
-  JumpTableHeader JTH(First, Last, SV, CR.CaseBB, (CR.CaseBB == SwitchBB));
-  if (CR.CaseBB == SwitchBB)
-    visitJumpTableHeader(JT, JTH, SwitchBB);
+  // Set NextBlock to be the MBB immediately after the current one, if any.
+  // This is used to avoid emitting unnecessary branches to the next block.
+  MachineBasicBlock *NextBlock = 0;
+  MachineFunction::iterator BBI = SwitchBB;
+  if (++BBI != FuncInfo.MF->end())
+    NextBlock = BBI;
 
-  JTCases.push_back(JumpTableBlock(JTH, JT));
+  MachineBasicBlock* MBB = B.Cases[0].ThisBB;
 
-  return true;
+  SwitchBB->addSuccessor(B.Default);
+  SwitchBB->addSuccessor(MBB);
+
+  SDValue BrRange = DAG.getNode(ISD::BRCOND, getCurDebugLoc(),
+                                MVT::Other, CopyTo, RangeCmp,
+                                DAG.getBasicBlock(B.Default));
+
+  if (MBB != NextBlock)
+    BrRange = DAG.getNode(ISD::BR, getCurDebugLoc(), MVT::Other, CopyTo,
+                          DAG.getBasicBlock(MBB));
+
+  DAG.setRoot(BrRange);
 }
 
-/// handleBTSplitSwitchCase - emit comparison and split binary search tree into
-/// 2 subtrees.
-bool SelectionDAGBuilder::handleBTSplitSwitchCase(CaseRec& CR,
-                                                  CaseRecVector& WorkList,
-                                                  const Value* SV,
-                                                  MachineBasicBlock *Default,
-                                                  MachineBasicBlock *SwitchBB) {
-  // Get the MachineFunction which holds the current MBB.  This is used when
-  // inserting any additional MBBs necessary to represent the switch.
-  MachineFunction *CurMF = FuncInfo.MF;
+/// visitBitTestCase - this function produces one "bit test"
+void SelectionDAGBuilder::visitBitTestCase(MachineBasicBlock* NextMBB,
+                                           unsigned Reg,
+                                           BitTestCase &B,
+                                           MachineBasicBlock *SwitchBB) {
+  // Make desired shift
+  SDValue ShiftOp = DAG.getCopyFromReg(getControlRoot(), getCurDebugLoc(), Reg,
+                                       TLI.getPointerTy());
+  SDValue SwitchVal = DAG.getNode(ISD::SHL, getCurDebugLoc(),
+                                  TLI.getPointerTy(),
+                                  DAG.getConstant(1, TLI.getPointerTy()),
+                                  ShiftOp);
 
-  // Figure out which block is immediately after the current one.
-  MachineFunction::iterator BBI = CR.CaseBB;
-  ++BBI;
+  // Emit bit tests and jumps
+  SDValue AndOp = DAG.getNode(ISD::AND, getCurDebugLoc(),
+                              TLI.getPointerTy(), SwitchVal,
+                              DAG.getConstant(B.Mask, TLI.getPointerTy()));
+  SDValue AndCmp = DAG.getSetCC(getCurDebugLoc(),
+                                TLI.getSetCCResultType(AndOp.getValueType()),
+                                AndOp, DAG.getConstant(0, TLI.getPointerTy()),
+                                ISD::SETNE);
 
-  Case& FrontCase = *CR.Range.first;
-  Case& BackCase  = *(CR.Range.second-1);
-  const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
+  SwitchBB->addSuccessor(B.TargetBB);
+  SwitchBB->addSuccessor(NextMBB);
 
-  // Size is the number of Cases represented by this range.
-  unsigned Size = CR.Range.second - CR.Range.first;
+  SDValue BrAnd = DAG.getNode(ISD::BRCOND, getCurDebugLoc(),
+                              MVT::Other, getControlRoot(),
+                              AndCmp, DAG.getBasicBlock(B.TargetBB));
 
-  const APInt &First = cast<ConstantInt>(FrontCase.Low)->getValue();
-  const APInt &Last  = cast<ConstantInt>(BackCase.High)->getValue();
-  double FMetric = 0;
-  CaseItr Pivot = CR.Range.first + Size/2;
+  // Set NextBlock to be the MBB immediately after the current one, if any.
+  // This is used to avoid emitting unnecessary branches to the next block.
+  MachineBasicBlock *NextBlock = 0;
+  MachineFunction::iterator BBI = SwitchBB;
+  if (++BBI != FuncInfo.MF->end())
+    NextBlock = BBI;
 
-  // Select optimal pivot, maximizing sum density of LHS and RHS. This will
-  // (heuristically) allow us to emit JumpTable's later.
-  APInt TSize(First.getBitWidth(), 0);
-  for (CaseItr I = CR.Range.first, E = CR.Range.second;
-       I!=E; ++I)
-    TSize += I->size();
+  if (NextMBB != NextBlock)
+    BrAnd = DAG.getNode(ISD::BR, getCurDebugLoc(), MVT::Other, BrAnd,
+                        DAG.getBasicBlock(NextMBB));
 
-  APInt LSize = FrontCase.size();
-  APInt RSize = TSize-LSize;
-  DEBUG(dbgs() << "Selecting best pivot: \n"
-               << "First: " << First << ", Last: " << Last <<'\n'
-               << "LSize: " << LSize << ", RSize: " << RSize << '\n');
-  for (CaseItr I = CR.Range.first, J=I+1, E = CR.Range.second;
-       J!=E; ++I, ++J) {
-    const APInt &LEnd = cast<ConstantInt>(I->High)->getValue();
-    const APInt &RBegin = cast<ConstantInt>(J->Low)->getValue();
-    APInt Range = ComputeRange(LEnd, RBegin);
-    assert((Range - 2ULL).isNonNegative() &&
-           "Invalid case distance");
-    double LDensity = (double)LSize.roundToDouble() /
-                           (LEnd - First + 1ULL).roundToDouble();
-    double RDensity = (double)RSize.roundToDouble() /
-                           (Last - RBegin + 1ULL).roundToDouble();
-    double Metric = Range.logBase2()*(LDensity+RDensity);
-    // Should always split in some non-trivial place
-    DEBUG(dbgs() <<"=>Step\n"
-                 << "LEnd: " << LEnd << ", RBegin: " << RBegin << '\n'
-                 << "LDensity: " << LDensity
-                 << ", RDensity: " << RDensity << '\n'
-                 << "Metric: " << Metric << '\n');
-    if (FMetric < Metric) {
-      Pivot = J;
-      FMetric = Metric;
-      DEBUG(dbgs() << "Current metric set to: " << FMetric << '\n');
-    }
-
-    LSize += J->size();
-    RSize -= J->size();
-  }
-  if (areJTsAllowed(TLI)) {
-    // If our case is dense we *really* should handle it earlier!
-    assert((FMetric > 0) && "Should handle dense range earlier!");
-  } else {
-    Pivot = CR.Range.first + Size/2;
-  }
-
-  CaseRange LHSR(CR.Range.first, Pivot);
-  CaseRange RHSR(Pivot, CR.Range.second);
-  Constant *C = Pivot->Low;
-  MachineBasicBlock *FalseBB = 0, *TrueBB = 0;
-
-  // We know that we branch to the LHS if the Value being switched on is
-  // less than the Pivot value, C.  We use this to optimize our binary
-  // tree a bit, by recognizing that if SV is greater than or equal to the
-  // LHS's Case Value, and that Case Value is exactly one less than the
-  // Pivot's Value, then we can branch directly to the LHS's Target,
-  // rather than creating a leaf node for it.
-  if ((LHSR.second - LHSR.first) == 1 &&
-      LHSR.first->High == CR.GE &&
-      cast<ConstantInt>(C)->getValue() ==
-      (cast<ConstantInt>(CR.GE)->getValue() + 1LL)) {
-    TrueBB = LHSR.first->BB;
-  } else {
-    TrueBB = CurMF->CreateMachineBasicBlock(LLVMBB);
-    CurMF->insert(BBI, TrueBB);
-    WorkList.push_back(CaseRec(TrueBB, C, CR.GE, LHSR));
+  DAG.setRoot(BrAnd);
+}
 
-    // Put SV in a virtual register to make it available from the new blocks.
-    ExportFromCurrentBlock(SV);
-  }
+void SelectionDAGBuilder::visitInvoke(const InvokeInst &I) {
+  MachineBasicBlock *InvokeMBB = FuncInfo.MBBMap[I.getParent()];
 
-  // Similar to the optimization above, if the Value being switched on is
-  // known to be less than the Constant CR.LT, and the current Case Value
-  // is CR.LT - 1, then we can branch directly to the target block for
-  // the current Case Value, rather than emitting a RHS leaf node for it.
-  if ((RHSR.second - RHSR.first) == 1 && CR.LT &&
-      cast<ConstantInt>(RHSR.first->Low)->getValue() ==
-      (cast<ConstantInt>(CR.LT)->getValue() - 1LL)) {
-    FalseBB = RHSR.first->BB;
-  } else {
-    FalseBB = CurMF->CreateMachineBasicBlock(LLVMBB);
-    CurMF->insert(BBI, FalseBB);
-    WorkList.push_back(CaseRec(FalseBB,CR.LT,C,RHSR));
+  // Retrieve successors.
+  MachineBasicBlock *Return = FuncInfo.MBBMap[I.getSuccessor(0)];
+  MachineBasicBlock *LandingPad = FuncInfo.MBBMap[I.getSuccessor(1)];
 
-    // Put SV in a virtual register to make it available from the new blocks.
-    ExportFromCurrentBlock(SV);
-  }
+  const Value *Callee(I.getCalledValue());
+  if (isa<InlineAsm>(Callee))
+    visitInlineAsm(&I);
+  else
+    LowerCallTo(&I, getValue(Callee), false, LandingPad);
 
-  // Create a CaseBlock record representing a conditional branch to
-  // the LHS node if the value being switched on SV is less than C.
-  // Otherwise, branch to LHS.
-  CaseBlock CB(ISD::SETLT, SV, C, NULL, TrueBB, FalseBB, CR.CaseBB);
+  // If the value of the invoke is used outside of its defining block, make it
+  // available as a virtual register.
+  CopyToExportRegsIfNeeded(&I);
 
-  if (CR.CaseBB == SwitchBB)
-    visitSwitchCase(CB, SwitchBB);
-  else
-    SwitchCases.push_back(CB);
+  // Update successor info
+  InvokeMBB->addSuccessor(Return);
+  InvokeMBB->addSuccessor(LandingPad);
 
-  return true;
+  // Drop into normal successor.
+  DAG.setRoot(DAG.getNode(ISD::BR, getCurDebugLoc(),
+                          MVT::Other, getControlRoot(),
+                          DAG.getBasicBlock(Return)));
 }
 
-/// handleBitTestsSwitchCase - if current case range has few destination and
-/// range span less, than machine word bitwidth, encode case range into series
-/// of masks and emit bit tests with these masks.
-bool SelectionDAGBuilder::handleBitTestsSwitchCase(CaseRec& CR,
-                                                   CaseRecVector& WorkList,
-                                                   const Value* SV,
-                                                   MachineBasicBlock* Default,
-                                                   MachineBasicBlock *SwitchBB){
-  EVT PTy = TLI.getPointerTy();
-  unsigned IntPtrBits = PTy.getSizeInBits();
+void SelectionDAGBuilder::visitUnwind(const UnwindInst &I) {
+}
 
-  Case& FrontCase = *CR.Range.first;
+/// handleSmallSwitchCaseRange - Emit a series of specific tests (suitable for
+/// small case ranges).
+bool SelectionDAGBuilder::handleSmallSwitchRange(CaseRec& CR,
+                                                 CaseRecVector& WorkList,
+                                                 const Value* SV,
+                                                 MachineBasicBlock *Default,
+                                                 MachineBasicBlock *SwitchBB) {
   Case& BackCase  = *(CR.Range.second-1);
 
+  // Size is the number of Cases represented by this range.
+  size_t Size = CR.Range.second - CR.Range.first;
+  if (Size > 3)
+    return false;
+
   // Get the MachineFunction which holds the current MBB.  This is used when
   // inserting any additional MBBs necessary to represent the switch.
   MachineFunction *CurMF = FuncInfo.MF;
 
-  // If target does not have legal shift left, do not emit bit tests at all.
-  if (!TLI.isOperationLegal(ISD::SHL, TLI.getPointerTy()))
-    return false;
-
-  size_t numCmps = 0;
-  for (CaseItr I = CR.Range.first, E = CR.Range.second;
-       I!=E; ++I) {
-    // Single case counts one, case range - two.
-    numCmps += (I->Low == I->High ? 1 : 2);
-  }
-
-  // Count unique destinations
-  SmallSet<MachineBasicBlock*, 4> Dests;
-  for (CaseItr I = CR.Range.first, E = CR.Range.second; I!=E; ++I) {
-    Dests.insert(I->BB);
-    if (Dests.size() > 3)
-      // Don't bother the code below, if there are too much unique destinations
-      return false;
-  }
-  DEBUG(dbgs() << "Total number of unique destinations: "
-        << Dests.size() << '\n'
-        << "Total number of comparisons: " << numCmps << '\n');
-
-  // Compute span of values.
-  const APInt& minValue = cast<ConstantInt>(FrontCase.Low)->getValue();
-  const APInt& maxValue = cast<ConstantInt>(BackCase.High)->getValue();
-  APInt cmpRange = maxValue - minValue;
-
-  DEBUG(dbgs() << "Compare range: " << cmpRange << '\n'
-               << "Low bound: " << minValue << '\n'
-               << "High bound: " << maxValue << '\n');
-
-  if (cmpRange.uge(IntPtrBits) ||
-      (!(Dests.size() == 1 && numCmps >= 3) &&
-       !(Dests.size() == 2 && numCmps >= 5) &&
-       !(Dests.size() >= 3 && numCmps >= 6)))
-    return false;
-
-  DEBUG(dbgs() << "Emitting bit tests\n");
-  APInt lowBound = APInt::getNullValue(cmpRange.getBitWidth());
+  // Figure out which block is immediately after the current one.
+  MachineBasicBlock *NextBlock = 0;
+  MachineFunction::iterator BBI = CR.CaseBB;
 
-  // Optimize the case where all the case values fit in a
-  // word without having to subtract minValue. In this case,
-  // we can optimize away the subtraction.
-  if (minValue.isNonNegative() && maxValue.slt(IntPtrBits)) {
-    cmpRange = maxValue;
-  } else {
-    lowBound = minValue;
-  }
+  if (++BBI != FuncInfo.MF->end())
+    NextBlock = BBI;
 
-  CaseBitsVector CasesBits;
-  unsigned i, count = 0;
+  // TODO: If any two of the cases has the same destination, and if one value
+  // is the same as the other, but has one bit unset that the other has set,
+  // use bit manipulation to do two compares at once.  For example:
+  // "if (X == 6 || X == 4)" -> "if ((X|2) == 6)"
 
-  for (CaseItr I = CR.Range.first, E = CR.Range.second; I!=E; ++I) {
-    MachineBasicBlock* Dest = I->BB;
-    for (i = 0; i < count; ++i)
-      if (Dest == CasesBits[i].BB)
+  // Rearrange the case blocks so that the last one falls through if possible.
+  if (NextBlock && Default != NextBlock && BackCase.BB != NextBlock) {
+    // The last case block won't fall through into 'NextBlock' if we emit the
+    // branches in this order.  See if rearranging a case value would help.
+    for (CaseItr I = CR.Range.first, E = CR.Range.second-1; I != E; ++I) {
+      if (I->BB == NextBlock) {
+        std::swap(*I, BackCase);
         break;
-
-    if (i == count) {
-      assert((count < 3) && "Too much destinations to test!");
-      CasesBits.push_back(CaseBits(0, Dest, 0));
-      count++;
+      }
     }
+  }
 
-    const APInt& lowValue = cast<ConstantInt>(I->Low)->getValue();
-    const APInt& highValue = cast<ConstantInt>(I->High)->getValue();
+  // Create a CaseBlock record representing a conditional branch to
+  // the Case's target mbb if the value being switched on SV is equal
+  // to C.
+  MachineBasicBlock *CurBlock = CR.CaseBB;
+  for (CaseItr I = CR.Range.first, E = CR.Range.second; I != E; ++I) {
+    MachineBasicBlock *FallThrough;
+    if (I != E-1) {
+      FallThrough = CurMF->CreateMachineBasicBlock(CurBlock->getBasicBlock());
+      CurMF->insert(BBI, FallThrough);
 
-    uint64_t lo = (lowValue - lowBound).getZExtValue();
-    uint64_t hi = (highValue - lowBound).getZExtValue();
+      // Put SV in a virtual register to make it available from the new blocks.
+      ExportFromCurrentBlock(SV);
+    } else {
+      // If the last case doesn't match, go to the default block.
+      FallThrough = Default;
+    }
 
-    for (uint64_t j = lo; j <= hi; j++) {
-      CasesBits[i].Mask |=  1ULL << j;
-      CasesBits[i].Bits++;
+    const Value *RHS, *LHS, *MHS;
+    ISD::CondCode CC;
+    if (I->High == I->Low) {
+      // This is just small small case range :) containing exactly 1 case
+      CC = ISD::SETEQ;
+      LHS = SV; RHS = I->High; MHS = NULL;
+    } else {
+      CC = ISD::SETLE;
+      LHS = I->Low; MHS = SV; RHS = I->High;
     }
+    CaseBlock CB(CC, LHS, RHS, MHS, I->BB, FallThrough, CurBlock);
 
-  }
-  std::sort(CasesBits.begin(), CasesBits.end(), CaseBitsCmp());
+    // If emitting the first comparison, just call visitSwitchCase to emit the
+    // code into the current block.  Otherwise, push the CaseBlock onto the
+    // vector to be later processed by SDISel, and insert the node's MBB
+    // before the next MBB.
+    if (CurBlock == SwitchBB)
+      visitSwitchCase(CB, SwitchBB);
+    else
+      SwitchCases.push_back(CB);
 
-  BitTestInfo BTC;
+    CurBlock = FallThrough;
+  }
 
-  // Figure out which block is immediately after the current one.
-  MachineFunction::iterator BBI = CR.CaseBB;
-  ++BBI;
+  return true;
+}
 
-  const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
-
-  DEBUG(dbgs() << "Cases:\n");
-  for (unsigned i = 0, e = CasesBits.size(); i!=e; ++i) {
-    DEBUG(dbgs() << "Mask: " << CasesBits[i].Mask
-                 << ", Bits: " << CasesBits[i].Bits
-                 << ", BB: " << CasesBits[i].BB << '\n');
-
-    MachineBasicBlock *CaseBB = CurMF->CreateMachineBasicBlock(LLVMBB);
-    CurMF->insert(BBI, CaseBB);
-    BTC.push_back(BitTestCase(CasesBits[i].Mask,
-                              CaseBB,
-                              CasesBits[i].BB));
-
-    // Put SV in a virtual register to make it available from the new blocks.
-    ExportFromCurrentBlock(SV);
-  }
-
-  BitTestBlock BTB(lowBound, cmpRange, SV,
-                   -1U, (CR.CaseBB == SwitchBB),
-                   CR.CaseBB, Default, BTC);
-
-  if (CR.CaseBB == SwitchBB)
-    visitBitTestHeader(BTB, SwitchBB);
-
-  BitTestCases.push_back(BTB);
+static inline bool areJTsAllowed(const TargetLowering &TLI) {
+  return !DisableJumpTables &&
+          (TLI.isOperationLegalOrCustom(ISD::BR_JT, MVT::Other) ||
+           TLI.isOperationLegalOrCustom(ISD::BRIND, MVT::Other));
+}
 
-  return true;
+static APInt ComputeRange(const APInt &First, const APInt &Last) {
+  APInt LastExt(Last), FirstExt(First);
+  uint32_t BitWidth = std::max(Last.getBitWidth(), First.getBitWidth()) + 1;
+  LastExt.sext(BitWidth); FirstExt.sext(BitWidth);
+  return (LastExt - FirstExt + 1ULL);
 }
 
-/// Clusterify - Transform simple list of Cases into list of CaseRange's
-size_t SelectionDAGBuilder::Clusterify(CaseVector& Cases,
-                                       const SwitchInst& SI) {
-  size_t numCmps = 0;
+/// handleJTSwitchCase - Emit jumptable for current switch case range
+bool SelectionDAGBuilder::handleJTSwitchCase(CaseRec& CR,
+                                             CaseRecVector& WorkList,
+                                             const Value* SV,
+                                             MachineBasicBlock* Default,
+                                             MachineBasicBlock *SwitchBB) {
+  Case& FrontCase = *CR.Range.first;
+  Case& BackCase  = *(CR.Range.second-1);
 
-  // Start with "simple" cases
-  for (size_t i = 1; i < SI.getNumSuccessors(); ++i) {
-    MachineBasicBlock *SMBB = FuncInfo.MBBMap[SI.getSuccessor(i)];
-    Cases.push_back(Case(SI.getSuccessorValue(i),
-                         SI.getSuccessorValue(i),
-                         SMBB));
-  }
-  std::sort(Cases.begin(), Cases.end(), CaseCmp());
+  const APInt &First = cast<ConstantInt>(FrontCase.Low)->getValue();
+  const APInt &Last  = cast<ConstantInt>(BackCase.High)->getValue();
 
-  // Merge case into clusters
-  if (Cases.size() >= 2)
-    // Must recompute end() each iteration because it may be
-    // invalidated by erase if we hold on to it
-    for (CaseItr I = Cases.begin(), J = ++(Cases.begin()); J != Cases.end(); ) {
-      const APInt& nextValue = cast<ConstantInt>(J->Low)->getValue();
-      const APInt& currentValue = cast<ConstantInt>(I->High)->getValue();
-      MachineBasicBlock* nextBB = J->BB;
-      MachineBasicBlock* currentBB = I->BB;
+  APInt TSize(First.getBitWidth(), 0);
+  for (CaseItr I = CR.Range.first, E = CR.Range.second;
+       I!=E; ++I)
+    TSize += I->size();
 
-      // If the two neighboring cases go to the same destination, merge them
-      // into a single case.
-      if ((nextValue - currentValue == 1) && (currentBB == nextBB)) {
-        I->High = J->High;
-        J = Cases.erase(J);
-      } else {
-        I = J++;
-      }
-    }
+  if (!areJTsAllowed(TLI) || TSize.ult(4))
+    return false;
 
-  for (CaseItr I=Cases.begin(), E=Cases.end(); I!=E; ++I, ++numCmps) {
-    if (I->Low != I->High)
-      // A range counts double, since it requires two compares.
-      ++numCmps;
-  }
+  APInt Range = ComputeRange(First, Last);
+  double Density = TSize.roundToDouble() / Range.roundToDouble();
+  if (Density < 0.4)
+    return false;
 
-  return numCmps;
-}
+  DEBUG(dbgs() << "Lowering jump table\n"
+               << "First entry: " << First << ". Last entry: " << Last << '\n'
+               << "Range: " << Range
+               << "Size: " << TSize << ". Density: " << Density << "\n\n");
 
-void SelectionDAGBuilder::visitSwitch(const SwitchInst &SI) {
-  MachineBasicBlock *SwitchMBB = FuncInfo.MBBMap[SI.getParent()];
+  // Get the MachineFunction which holds the current MBB.  This is used when
+  // inserting any additional MBBs necessary to represent the switch.
+  MachineFunction *CurMF = FuncInfo.MF;
 
   // Figure out which block is immediately after the current one.
-  MachineBasicBlock *NextBlock = 0;
-  MachineBasicBlock *Default = FuncInfo.MBBMap[SI.getDefaultDest()];
+  MachineFunction::iterator BBI = CR.CaseBB;
+  ++BBI;
 
-  // If there is only the default destination, branch to it if it is not the
-  // next basic block.  Otherwise, just fall through.
-  if (SI.getNumOperands() == 2) {
-    // Update machine-CFG edges.
+  const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
 
-    // If this is not a fall-through branch, emit the branch.
-    SwitchMBB->addSuccessor(Default);
-    if (Default != NextBlock)
-      DAG.setRoot(DAG.getNode(ISD::BR, getCurDebugLoc(),
-                              MVT::Other, getControlRoot(),
-                              DAG.getBasicBlock(Default)));
+  // Create a new basic block to hold the code for loading the address
+  // of the jump table, and jumping to it.  Update successor information;
+  // we will either branch to the default case for the switch, or the jump
+  // table.
+  MachineBasicBlock *JumpTableBB = CurMF->CreateMachineBasicBlock(LLVMBB);
+  CurMF->insert(BBI, JumpTableBB);
+  CR.CaseBB->addSuccessor(Default);
+  CR.CaseBB->addSuccessor(JumpTableBB);
 
-    return;
+  // Build a vector of destination BBs, corresponding to each target
+  // of the jump table. If the value of the jump table slot corresponds to
+  // a case statement, push the case's BB onto the vector, otherwise, push
+  // the default BB.
+  std::vector<MachineBasicBlock*> DestBBs;
+  APInt TEI = First;
+  for (CaseItr I = CR.Range.first, E = CR.Range.second; I != E; ++TEI) {
+    const APInt &Low = cast<ConstantInt>(I->Low)->getValue();
+    const APInt &High = cast<ConstantInt>(I->High)->getValue();
+
+    if (Low.sle(TEI) && TEI.sle(High)) {
+      DestBBs.push_back(I->BB);
+      if (TEI==High)
+        ++I;
+    } else {
+      DestBBs.push_back(Default);
+    }
   }
 
-  // If there are any non-default case statements, create a vector of Cases
-  // representing each one, and sort the vector so that we can efficiently
-  // create a binary search tree from them.
-  CaseVector Cases;
-  size_t numCmps = Clusterify(Cases, SI);
-  DEBUG(dbgs() << "Clusterify finished. Total clusters: " << Cases.size()
-               << ". Total compares: " << numCmps << '\n');
-  numCmps = 0;
+  // Update successor info. Add one edge to each unique successor.
+  BitVector SuccsHandled(CR.CaseBB->getParent()->getNumBlockIDs());
+  for (std::vector<MachineBasicBlock*>::iterator I = DestBBs.begin(),
+         E = DestBBs.end(); I != E; ++I) {
+    if (!SuccsHandled[(*I)->getNumber()]) {
+      SuccsHandled[(*I)->getNumber()] = true;
+      JumpTableBB->addSuccessor(*I);
+    }
+  }
 
-  // Get the Value to be switched on and default basic blocks, which will be
-  // inserted into CaseBlock records, representing basic blocks in the binary
-  // search tree.
-  const Value *SV = SI.getOperand(0);
+  // Create a jump table index for this jump table.
+  unsigned JTEncoding = TLI.getJumpTableEncoding();
+  unsigned JTI = CurMF->getOrCreateJumpTableInfo(JTEncoding)
+                       ->createJumpTableIndex(DestBBs);
 
-  // Push the initial CaseRec onto the worklist
-  CaseRecVector WorkList;
-  WorkList.push_back(CaseRec(SwitchMBB,0,0,
-                             CaseRange(Cases.begin(),Cases.end())));
+  // Set the jump table information so that we can codegen it as a second
+  // MachineBasicBlock
+  JumpTable JT(-1U, JTI, JumpTableBB, Default);
+  JumpTableHeader JTH(First, Last, SV, CR.CaseBB, (CR.CaseBB == SwitchBB));
+  if (CR.CaseBB == SwitchBB)
+    visitJumpTableHeader(JT, JTH, SwitchBB);
 
-  while (!WorkList.empty()) {
-    // Grab a record representing a case range to process off the worklist
-    CaseRec CR = WorkList.back();
-    WorkList.pop_back();
+  JTCases.push_back(JumpTableBlock(JTH, JT));
 
-    if (handleBitTestsSwitchCase(CR, WorkList, SV, Default, SwitchMBB))
-      continue;
+  return true;
+}
 
-    // If the range has few cases (two or less) emit a series of specific
-    // tests.
-    if (handleSmallSwitchRange(CR, WorkList, SV, Default, SwitchMBB))
-      continue;
+/// handleBTSplitSwitchCase - emit comparison and split binary search tree into
+/// 2 subtrees.
+bool SelectionDAGBuilder::handleBTSplitSwitchCase(CaseRec& CR,
+                                                  CaseRecVector& WorkList,
+                                                  const Value* SV,
+                                                  MachineBasicBlock *Default,
+                                                  MachineBasicBlock *SwitchBB) {
+  // Get the MachineFunction which holds the current MBB.  This is used when
+  // inserting any additional MBBs necessary to represent the switch.
+  MachineFunction *CurMF = FuncInfo.MF;
 
-    // If the switch has more than 5 blocks, and at least 40% dense, and the
-    // target supports indirect branches, then emit a jump table rather than
-    // lowering the switch to a binary tree of conditional branches.
-    if (handleJTSwitchCase(CR, WorkList, SV, Default, SwitchMBB))
-      continue;
+  // Figure out which block is immediately after the current one.
+  MachineFunction::iterator BBI = CR.CaseBB;
+  ++BBI;
 
-    // Emit binary tree. We need to pick a pivot, and push left and right ranges
-    // onto the worklist. Leafs are handled via handleSmallSwitchRange() call.
-    handleBTSplitSwitchCase(CR, WorkList, SV, Default, SwitchMBB);
-  }
-}
+  Case& FrontCase = *CR.Range.first;
+  Case& BackCase  = *(CR.Range.second-1);
+  const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
 
-void SelectionDAGBuilder::visitIndirectBr(const IndirectBrInst &I) {
-  MachineBasicBlock *IndirectBrMBB = FuncInfo.MBBMap[I.getParent()];
+  // Size is the number of Cases represented by this range.
+  unsigned Size = CR.Range.second - CR.Range.first;
 
-  // Update machine-CFG edges with unique successors.
-  SmallVector<BasicBlock*, 32> succs;
-  succs.reserve(I.getNumSuccessors());
-  for (unsigned i = 0, e = I.getNumSuccessors(); i != e; ++i)
-    succs.push_back(I.getSuccessor(i));
-  array_pod_sort(succs.begin(), succs.end());
-  succs.erase(std::unique(succs.begin(), succs.end()), succs.end());
-  for (unsigned i = 0, e = succs.size(); i != e; ++i)
-    IndirectBrMBB->addSuccessor(FuncInfo.MBBMap[succs[i]]);
+  const APInt &First = cast<ConstantInt>(FrontCase.Low)->getValue();
+  const APInt &Last  = cast<ConstantInt>(BackCase.High)->getValue();
+  double FMetric = 0;
+  CaseItr Pivot = CR.Range.first + Size/2;
 
-  DAG.setRoot(DAG.getNode(ISD::BRIND, getCurDebugLoc(),
-                          MVT::Other, getControlRoot(),
-                          getValue(I.getAddress())));
-}
+  // Select optimal pivot, maximizing sum density of LHS and RHS. This will
+  // (heuristically) allow us to emit JumpTable's later.
+  APInt TSize(First.getBitWidth(), 0);
+  for (CaseItr I = CR.Range.first, E = CR.Range.second;
+       I!=E; ++I)
+    TSize += I->size();
 
-void SelectionDAGBuilder::visitFSub(const User &I) {
-  // -0.0 - X --> fneg
-  const Type *Ty = I.getType();
-  if (Ty->isVectorTy()) {
-    if (ConstantVector *CV = dyn_cast<ConstantVector>(I.getOperand(0))) {
-      const VectorType *DestTy = cast<VectorType>(I.getType());
-      const Type *ElTy = DestTy->getElementType();
-      unsigned VL = DestTy->getNumElements();
-      std::vector<Constant*> NZ(VL, ConstantFP::getNegativeZero(ElTy));
-      Constant *CNZ = ConstantVector::get(&NZ[0], NZ.size());
-      if (CV == CNZ) {
-        SDValue Op2 = getValue(I.getOperand(1));
-        setValue(&I, DAG.getNode(ISD::FNEG, getCurDebugLoc(),
-                                 Op2.getValueType(), Op2));
-        return;
-      }
+  APInt LSize = FrontCase.size();
+  APInt RSize = TSize-LSize;
+  DEBUG(dbgs() << "Selecting best pivot: \n"
+               << "First: " << First << ", Last: " << Last <<'\n'
+               << "LSize: " << LSize << ", RSize: " << RSize << '\n');
+  for (CaseItr I = CR.Range.first, J=I+1, E = CR.Range.second;
+       J!=E; ++I, ++J) {
+    const APInt &LEnd = cast<ConstantInt>(I->High)->getValue();
+    const APInt &RBegin = cast<ConstantInt>(J->Low)->getValue();
+    APInt Range = ComputeRange(LEnd, RBegin);
+    assert((Range - 2ULL).isNonNegative() &&
+           "Invalid case distance");
+    double LDensity = (double)LSize.roundToDouble() /
+                           (LEnd - First + 1ULL).roundToDouble();
+    double RDensity = (double)RSize.roundToDouble() /
+                           (Last - RBegin + 1ULL).roundToDouble();
+    double Metric = Range.logBase2()*(LDensity+RDensity);
+    // Should always split in some non-trivial place
+    DEBUG(dbgs() <<"=>Step\n"
+                 << "LEnd: " << LEnd << ", RBegin: " << RBegin << '\n'
+                 << "LDensity: " << LDensity
+                 << ", RDensity: " << RDensity << '\n'
+                 << "Metric: " << Metric << '\n');
+    if (FMetric < Metric) {
+      Pivot = J;
+      FMetric = Metric;
+      DEBUG(dbgs() << "Current metric set to: " << FMetric << '\n');
     }
+
+    LSize += J->size();
+    RSize -= J->size();
+  }
+  if (areJTsAllowed(TLI)) {
+    // If our case is dense we *really* should handle it earlier!
+    assert((FMetric > 0) && "Should handle dense range earlier!");
+  } else {
+    Pivot = CR.Range.first + Size/2;
   }
 
-  if (ConstantFP *CFP = dyn_cast<ConstantFP>(I.getOperand(0)))
-    if (CFP->isExactlyValue(ConstantFP::getNegativeZero(Ty)->getValueAPF())) {
-      SDValue Op2 = getValue(I.getOperand(1));
-      setValue(&I, DAG.getNode(ISD::FNEG, getCurDebugLoc(),
-                               Op2.getValueType(), Op2));
-      return;
-    }
+  CaseRange LHSR(CR.Range.first, Pivot);
+  CaseRange RHSR(Pivot, CR.Range.second);
+  Constant *C = Pivot->Low;
+  MachineBasicBlock *FalseBB = 0, *TrueBB = 0;
 
-  visitBinary(I, ISD::FSUB);
-}
+  // We know that we branch to the LHS if the Value being switched on is
+  // less than the Pivot value, C.  We use this to optimize our binary
+  // tree a bit, by recognizing that if SV is greater than or equal to the
+  // LHS's Case Value, and that Case Value is exactly one less than the
+  // Pivot's Value, then we can branch directly to the LHS's Target,
+  // rather than creating a leaf node for it.
+  if ((LHSR.second - LHSR.first) == 1 &&
+      LHSR.first->High == CR.GE &&
+      cast<ConstantInt>(C)->getValue() ==
+      (cast<ConstantInt>(CR.GE)->getValue() + 1LL)) {
+    TrueBB = LHSR.first->BB;
+  } else {
+    TrueBB = CurMF->CreateMachineBasicBlock(LLVMBB);
+    CurMF->insert(BBI, TrueBB);
+    WorkList.push_back(CaseRec(TrueBB, C, CR.GE, LHSR));
 
-void SelectionDAGBuilder::visitBinary(const User &I, unsigned OpCode) {
-  SDValue Op1 = getValue(I.getOperand(0));
-  SDValue Op2 = getValue(I.getOperand(1));
-  setValue(&I, DAG.getNode(OpCode, getCurDebugLoc(),
-                           Op1.getValueType(), Op1, Op2));
-}
+    // Put SV in a virtual register to make it available from the new blocks.
+    ExportFromCurrentBlock(SV);
+  }
 
-void SelectionDAGBuilder::visitShift(const User &I, unsigned Opcode) {
-  SDValue Op1 = getValue(I.getOperand(0));
-  SDValue Op2 = getValue(I.getOperand(1));
-  if (!I.getType()->isVectorTy() &&
-      Op2.getValueType() != TLI.getShiftAmountTy()) {
-    // If the operand is smaller than the shift count type, promote it.
-    EVT PTy = TLI.getPointerTy();
-    EVT STy = TLI.getShiftAmountTy();
-    if (STy.bitsGT(Op2.getValueType()))
-      Op2 = DAG.getNode(ISD::ANY_EXTEND, getCurDebugLoc(),
-                        TLI.getShiftAmountTy(), Op2);
-    // If the operand is larger than the shift count type but the shift
-    // count type has enough bits to represent any shift value, truncate
-    // it now. This is a common case and it exposes the truncate to
-    // optimization early.
-    else if (STy.getSizeInBits() >=
-             Log2_32_Ceil(Op2.getValueType().getSizeInBits()))
-      Op2 = DAG.getNode(ISD::TRUNCATE, getCurDebugLoc(),
-                        TLI.getShiftAmountTy(), Op2);
-    // Otherwise we'll need to temporarily settle for some other
-    // convenient type; type legalization will make adjustments as
-    // needed.
-    else if (PTy.bitsLT(Op2.getValueType()))
-      Op2 = DAG.getNode(ISD::TRUNCATE, getCurDebugLoc(),
-                        TLI.getPointerTy(), Op2);
-    else if (PTy.bitsGT(Op2.getValueType()))
-      Op2 = DAG.getNode(ISD::ANY_EXTEND, getCurDebugLoc(),
-                        TLI.getPointerTy(), Op2);
+  // Similar to the optimization above, if the Value being switched on is
+  // known to be less than the Constant CR.LT, and the current Case Value
+  // is CR.LT - 1, then we can branch directly to the target block for
+  // the current Case Value, rather than emitting a RHS leaf node for it.
+  if ((RHSR.second - RHSR.first) == 1 && CR.LT &&
+      cast<ConstantInt>(RHSR.first->Low)->getValue() ==
+      (cast<ConstantInt>(CR.LT)->getValue() - 1LL)) {
+    FalseBB = RHSR.first->BB;
+  } else {
+    FalseBB = CurMF->CreateMachineBasicBlock(LLVMBB);
+    CurMF->insert(BBI, FalseBB);
+    WorkList.push_back(CaseRec(FalseBB,CR.LT,C,RHSR));
+
+    // Put SV in a virtual register to make it available from the new blocks.
+    ExportFromCurrentBlock(SV);
   }
 
-  setValue(&I, DAG.getNode(Opcode, getCurDebugLoc(),
-                           Op1.getValueType(), Op1, Op2));
-}
+  // Create a CaseBlock record representing a conditional branch to
+  // the LHS node if the value being switched on SV is less than C.
+  // Otherwise, branch to LHS.
+  CaseBlock CB(ISD::SETLT, SV, C, NULL, TrueBB, FalseBB, CR.CaseBB);
 
-void SelectionDAGBuilder::visitICmp(const User &I) {
-  ICmpInst::Predicate predicate = ICmpInst::BAD_ICMP_PREDICATE;
-  if (const ICmpInst *IC = dyn_cast<ICmpInst>(&I))
-    predicate = IC->getPredicate();
-  else if (const ConstantExpr *IC = dyn_cast<ConstantExpr>(&I))
-    predicate = ICmpInst::Predicate(IC->getPredicate());
-  SDValue Op1 = getValue(I.getOperand(0));
-  SDValue Op2 = getValue(I.getOperand(1));
-  ISD::CondCode Opcode = getICmpCondCode(predicate);
+  if (CR.CaseBB == SwitchBB)
+    visitSwitchCase(CB, SwitchBB);
+  else
+    SwitchCases.push_back(CB);
 
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getSetCC(getCurDebugLoc(), DestVT, Op1, Op2, Opcode));
+  return true;
 }
 
-void SelectionDAGBuilder::visitFCmp(const User &I) {
-  FCmpInst::Predicate predicate = FCmpInst::BAD_FCMP_PREDICATE;
-  if (const FCmpInst *FC = dyn_cast<FCmpInst>(&I))
-    predicate = FC->getPredicate();
-  else if (const ConstantExpr *FC = dyn_cast<ConstantExpr>(&I))
-    predicate = FCmpInst::Predicate(FC->getPredicate());
-  SDValue Op1 = getValue(I.getOperand(0));
-  SDValue Op2 = getValue(I.getOperand(1));
-  ISD::CondCode Condition = getFCmpCondCode(predicate);
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getSetCC(getCurDebugLoc(), DestVT, Op1, Op2, Condition));
-}
+/// handleBitTestsSwitchCase - if current case range has few destination and
+/// range span less, than machine word bitwidth, encode case range into series
+/// of masks and emit bit tests with these masks.
+bool SelectionDAGBuilder::handleBitTestsSwitchCase(CaseRec& CR,
+                                                   CaseRecVector& WorkList,
+                                                   const Value* SV,
+                                                   MachineBasicBlock* Default,
+                                                   MachineBasicBlock *SwitchBB){
+  EVT PTy = TLI.getPointerTy();
+  unsigned IntPtrBits = PTy.getSizeInBits();
 
-void SelectionDAGBuilder::visitSelect(const User &I) {
-  SmallVector<EVT, 4> ValueVTs;
-  ComputeValueVTs(TLI, I.getType(), ValueVTs);
-  unsigned NumValues = ValueVTs.size();
-  if (NumValues == 0) return;
+  Case& FrontCase = *CR.Range.first;
+  Case& BackCase  = *(CR.Range.second-1);
 
-  SmallVector<SDValue, 4> Values(NumValues);
-  SDValue Cond     = getValue(I.getOperand(0));
-  SDValue TrueVal  = getValue(I.getOperand(1));
-  SDValue FalseVal = getValue(I.getOperand(2));
+  // Get the MachineFunction which holds the current MBB.  This is used when
+  // inserting any additional MBBs necessary to represent the switch.
+  MachineFunction *CurMF = FuncInfo.MF;
 
-  for (unsigned i = 0; i != NumValues; ++i)
-    Values[i] = DAG.getNode(ISD::SELECT, getCurDebugLoc(),
-                          TrueVal.getNode()->getValueType(TrueVal.getResNo()+i),
-                            Cond,
-                            SDValue(TrueVal.getNode(),
-                                    TrueVal.getResNo() + i),
-                            SDValue(FalseVal.getNode(),
-                                    FalseVal.getResNo() + i));
+  // If target does not have legal shift left, do not emit bit tests at all.
+  if (!TLI.isOperationLegal(ISD::SHL, TLI.getPointerTy()))
+    return false;
 
-  setValue(&I, DAG.getNode(ISD::MERGE_VALUES, getCurDebugLoc(),
-                           DAG.getVTList(&ValueVTs[0], NumValues),
-                           &Values[0], NumValues));
-}
+  size_t numCmps = 0;
+  for (CaseItr I = CR.Range.first, E = CR.Range.second;
+       I!=E; ++I) {
+    // Single case counts one, case range - two.
+    numCmps += (I->Low == I->High ? 1 : 2);
+  }
 
-void SelectionDAGBuilder::visitTrunc(const User &I) {
-  // TruncInst cannot be a no-op cast because sizeof(src) > sizeof(dest).
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getNode(ISD::TRUNCATE, getCurDebugLoc(), DestVT, N));
-}
+  // Count unique destinations
+  SmallSet<MachineBasicBlock*, 4> Dests;
+  for (CaseItr I = CR.Range.first, E = CR.Range.second; I!=E; ++I) {
+    Dests.insert(I->BB);
+    if (Dests.size() > 3)
+      // Don't bother the code below, if there are too much unique destinations
+      return false;
+  }
+  DEBUG(dbgs() << "Total number of unique destinations: "
+        << Dests.size() << '\n'
+        << "Total number of comparisons: " << numCmps << '\n');
 
-void SelectionDAGBuilder::visitZExt(const User &I) {
-  // ZExt cannot be a no-op cast because sizeof(src) < sizeof(dest).
-  // ZExt also can't be a cast to bool for same reason. So, nothing much to do
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getNode(ISD::ZERO_EXTEND, getCurDebugLoc(), DestVT, N));
-}
+  // Compute span of values.
+  const APInt& minValue = cast<ConstantInt>(FrontCase.Low)->getValue();
+  const APInt& maxValue = cast<ConstantInt>(BackCase.High)->getValue();
+  APInt cmpRange = maxValue - minValue;
 
-void SelectionDAGBuilder::visitSExt(const User &I) {
-  // SExt cannot be a no-op cast because sizeof(src) < sizeof(dest).
-  // SExt also can't be a cast to bool for same reason. So, nothing much to do
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getNode(ISD::SIGN_EXTEND, getCurDebugLoc(), DestVT, N));
-}
+  DEBUG(dbgs() << "Compare range: " << cmpRange << '\n'
+               << "Low bound: " << minValue << '\n'
+               << "High bound: " << maxValue << '\n');
 
-void SelectionDAGBuilder::visitFPTrunc(const User &I) {
-  // FPTrunc is never a no-op cast, no need to check
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getNode(ISD::FP_ROUND, getCurDebugLoc(),
-                           DestVT, N, DAG.getIntPtrConstant(0)));
-}
+  if (cmpRange.uge(IntPtrBits) ||
+      (!(Dests.size() == 1 && numCmps >= 3) &&
+       !(Dests.size() == 2 && numCmps >= 5) &&
+       !(Dests.size() >= 3 && numCmps >= 6)))
+    return false;
 
-void SelectionDAGBuilder::visitFPExt(const User &I){
-  // FPTrunc is never a no-op cast, no need to check
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getNode(ISD::FP_EXTEND, getCurDebugLoc(), DestVT, N));
-}
+  DEBUG(dbgs() << "Emitting bit tests\n");
+  APInt lowBound = APInt::getNullValue(cmpRange.getBitWidth());
 
-void SelectionDAGBuilder::visitFPToUI(const User &I) {
-  // FPToUI is never a no-op cast, no need to check
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getNode(ISD::FP_TO_UINT, getCurDebugLoc(), DestVT, N));
-}
+  // Optimize the case where all the case values fit in a
+  // word without having to subtract minValue. In this case,
+  // we can optimize away the subtraction.
+  if (minValue.isNonNegative() && maxValue.slt(IntPtrBits)) {
+    cmpRange = maxValue;
+  } else {
+    lowBound = minValue;
+  }
 
-void SelectionDAGBuilder::visitFPToSI(const User &I) {
-  // FPToSI is never a no-op cast, no need to check
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getNode(ISD::FP_TO_SINT, getCurDebugLoc(), DestVT, N));
-}
+  CaseBitsVector CasesBits;
+  unsigned i, count = 0;
 
-void SelectionDAGBuilder::visitUIToFP(const User &I) {
-  // UIToFP is never a no-op cast, no need to check
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getNode(ISD::UINT_TO_FP, getCurDebugLoc(), DestVT, N));
-}
+  for (CaseItr I = CR.Range.first, E = CR.Range.second; I!=E; ++I) {
+    MachineBasicBlock* Dest = I->BB;
+    for (i = 0; i < count; ++i)
+      if (Dest == CasesBits[i].BB)
+        break;
 
-void SelectionDAGBuilder::visitSIToFP(const User &I){
-  // SIToFP is never a no-op cast, no need to check
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getNode(ISD::SINT_TO_FP, getCurDebugLoc(), DestVT, N));
-}
+    if (i == count) {
+      assert((count < 3) && "Too much destinations to test!");
+      CasesBits.push_back(CaseBits(0, Dest, 0));
+      count++;
+    }
 
-void SelectionDAGBuilder::visitPtrToInt(const User &I) {
-  // What to do depends on the size of the integer and the size of the pointer.
-  // We can either truncate, zero extend, or no-op, accordingly.
-  SDValue N = getValue(I.getOperand(0));
-  EVT SrcVT = N.getValueType();
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getZExtOrTrunc(N, getCurDebugLoc(), DestVT));
-}
+    const APInt& lowValue = cast<ConstantInt>(I->Low)->getValue();
+    const APInt& highValue = cast<ConstantInt>(I->High)->getValue();
 
-void SelectionDAGBuilder::visitIntToPtr(const User &I) {
-  // What to do depends on the size of the integer and the size of the pointer.
-  // We can either truncate, zero extend, or no-op, accordingly.
-  SDValue N = getValue(I.getOperand(0));
-  EVT SrcVT = N.getValueType();
-  EVT DestVT = TLI.getValueType(I.getType());
-  setValue(&I, DAG.getZExtOrTrunc(N, getCurDebugLoc(), DestVT));
-}
+    uint64_t lo = (lowValue - lowBound).getZExtValue();
+    uint64_t hi = (highValue - lowBound).getZExtValue();
 
-void SelectionDAGBuilder::visitBitCast(const User &I) {
-  SDValue N = getValue(I.getOperand(0));
-  EVT DestVT = TLI.getValueType(I.getType());
+    for (uint64_t j = lo; j <= hi; j++) {
+      CasesBits[i].Mask |=  1ULL << j;
+      CasesBits[i].Bits++;
+    }
 
-  // BitCast assures us that source and destination are the same size so this is
-  // either a BIT_CONVERT or a no-op.
-  if (DestVT != N.getValueType())
-    setValue(&I, DAG.getNode(ISD::BIT_CONVERT, getCurDebugLoc(),
-                             DestVT, N)); // convert types.
-  else
-    setValue(&I, N);            // noop cast.
-}
+  }
+  std::sort(CasesBits.begin(), CasesBits.end(), CaseBitsCmp());
 
-void SelectionDAGBuilder::visitInsertElement(const User &I) {
-  SDValue InVec = getValue(I.getOperand(0));
-  SDValue InVal = getValue(I.getOperand(1));
-  SDValue InIdx = DAG.getNode(ISD::ZERO_EXTEND, getCurDebugLoc(),
-                              TLI.getPointerTy(),
-                              getValue(I.getOperand(2)));
-  setValue(&I, DAG.getNode(ISD::INSERT_VECTOR_ELT, getCurDebugLoc(),
-                           TLI.getValueType(I.getType()),
-                           InVec, InVal, InIdx));
-}
+  BitTestInfo BTC;
 
-void SelectionDAGBuilder::visitExtractElement(const User &I) {
-  SDValue InVec = getValue(I.getOperand(0));
-  SDValue InIdx = DAG.getNode(ISD::ZERO_EXTEND, getCurDebugLoc(),
-                              TLI.getPointerTy(),
-                              getValue(I.getOperand(1)));
-  setValue(&I, DAG.getNode(ISD::EXTRACT_VECTOR_ELT, getCurDebugLoc(),
-                           TLI.getValueType(I.getType()), InVec, InIdx));
-}
+  // Figure out which block is immediately after the current one.
+  MachineFunction::iterator BBI = CR.CaseBB;
+  ++BBI;
 
-// Utility for visitShuffleVector - Returns true if the mask is mask starting
-// from SIndx and increasing to the element length (undefs are allowed).
-static bool SequentialMask(SmallVectorImpl<int> &Mask, unsigned SIndx) {
-  unsigned MaskNumElts = Mask.size();
-  for (unsigned i = 0; i != MaskNumElts; ++i)
-    if ((Mask[i] >= 0) && (Mask[i] != (int)(i + SIndx)))
-      return false;
-  return true;
-}
+  const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
 
-void SelectionDAGBuilder::visitShuffleVector(const User &I) {
-  SmallVector<int, 8> Mask;
-  SDValue Src1 = getValue(I.getOperand(0));
-  SDValue Src2 = getValue(I.getOperand(1));
+  DEBUG(dbgs() << "Cases:\n");
+  for (unsigned i = 0, e = CasesBits.size(); i!=e; ++i) {
+    DEBUG(dbgs() << "Mask: " << CasesBits[i].Mask
+                 << ", Bits: " << CasesBits[i].Bits
+                 << ", BB: " << CasesBits[i].BB << '\n');
 
-  // Convert the ConstantVector mask operand into an array of ints, with -1
-  // representing undef values.
-  SmallVector<Constant*, 8> MaskElts;
-  cast<Constant>(I.getOperand(2))->getVectorElements(MaskElts);
-  unsigned MaskNumElts = MaskElts.size();
-  for (unsigned i = 0; i != MaskNumElts; ++i) {
-    if (isa<UndefValue>(MaskElts[i]))
-      Mask.push_back(-1);
-    else
-      Mask.push_back(cast<ConstantInt>(MaskElts[i])->getSExtValue());
+    MachineBasicBlock *CaseBB = CurMF->CreateMachineBasicBlock(LLVMBB);
+    CurMF->insert(BBI, CaseBB);
+    BTC.push_back(BitTestCase(CasesBits[i].Mask,
+                              CaseBB,
+                              CasesBits[i].BB));
+
+    // Put SV in a virtual register to make it available from the new blocks.
+    ExportFromCurrentBlock(SV);
   }
 
-  EVT VT = TLI.getValueType(I.getType());
-  EVT SrcVT = Src1.getValueType();
-  unsigned SrcNumElts = SrcVT.getVectorNumElements();
+  BitTestBlock BTB(lowBound, cmpRange, SV,
+                   -1U, (CR.CaseBB == SwitchBB),
+                   CR.CaseBB, Default, BTC);
 
-  if (SrcNumElts == MaskNumElts) {
-    setValue(&I, DAG.getVectorShuffle(VT, getCurDebugLoc(), Src1, Src2,
-                                      &Mask[0]));
-    return;
-  }
+  if (CR.CaseBB == SwitchBB)
+    visitBitTestHeader(BTB, SwitchBB);
 
-  // Normalize the shuffle vector since mask and vector length don't match.
-  if (SrcNumElts < MaskNumElts && MaskNumElts % SrcNumElts == 0) {
-    // Mask is longer than the source vectors and is a multiple of the source
-    // vectors.  We can use concatenate vector to make the mask and vectors
-    // lengths match.
-    if (SrcNumElts*2 == MaskNumElts && SequentialMask(Mask, 0)) {
-      // The shuffle is concatenating two vectors together.
-      setValue(&I, DAG.getNode(ISD::CONCAT_VECTORS, getCurDebugLoc(),
-                               VT, Src1, Src2));
-      return;
-    }
+  BitTestCases.push_back(BTB);
 
-    // Pad both vectors with undefs to make them the same length as the mask.
-    unsigned NumConcat = MaskNumElts / SrcNumElts;
-    bool Src1U = Src1.getOpcode() == ISD::UNDEF;
-    bool Src2U = Src2.getOpcode() == ISD::UNDEF;
-    SDValue UndefVal = DAG.getUNDEF(SrcVT);
+  return true;
+}
 
-    SmallVector<SDValue, 8> MOps1(NumConcat, UndefVal);
-    SmallVector<SDValue, 8> MOps2(NumConcat, UndefVal);
-    MOps1[0] = Src1;
-    MOps2[0] = Src2;
+/// Clusterify - Transform simple list of Cases into list of CaseRange's
+size_t SelectionDAGBuilder::Clusterify(CaseVector& Cases,
+                                       const SwitchInst& SI) {
+  size_t numCmps = 0;
 
-    Src1 = Src1U ? DAG.getUNDEF(VT) : DAG.getNode(ISD::CONCAT_VECTORS,
-                                                  getCurDebugLoc(), VT,
-                                                  &MOps1[0], NumConcat);
-    Src2 = Src2U ? DAG.getUNDEF(VT) : DAG.getNode(ISD::CONCAT_VECTORS,
-                                                  getCurDebugLoc(), VT,
-                                                  &MOps2[0], NumConcat);
+  // Start with "simple" cases
+  for (size_t i = 1; i < SI.getNumSuccessors(); ++i) {
+    MachineBasicBlock *SMBB = FuncInfo.MBBMap[SI.getSuccessor(i)];
+    Cases.push_back(Case(SI.getSuccessorValue(i),
+                         SI.getSuccessorValue(i),
+                         SMBB));
+  }
+  std::sort(Cases.begin(), Cases.end(), CaseCmp());
 
-    // Readjust mask for new input vector length.
-    SmallVector<int, 8> MappedOps;
-    for (unsigned i = 0; i != MaskNumElts; ++i) {
-      int Idx = Mask[i];
-      if (Idx < (int)SrcNumElts)
-        MappedOps.push_back(Idx);
-      else
-        MappedOps.push_back(Idx + MaskNumElts - SrcNumElts);
+  // Merge case into clusters
+  if (Cases.size() >= 2)
+    // Must recompute end() each iteration because it may be
+    // invalidated by erase if we hold on to it
+    for (CaseItr I = Cases.begin(), J = ++(Cases.begin()); J != Cases.end(); ) {
+      const APInt& nextValue = cast<ConstantInt>(J->Low)->getValue();
+      const APInt& currentValue = cast<ConstantInt>(I->High)->getValue();
+      MachineBasicBlock* nextBB = J->BB;
+      MachineBasicBlock* currentBB = I->BB;
+
+      // If the two neighboring cases go to the same destination, merge them
+      // into a single case.
+      if ((nextValue - currentValue == 1) && (currentBB == nextBB)) {
+        I->High = J->High;
+        J = Cases.erase(J);
+      } else {
+        I = J++;
+      }
     }
 
-    setValue(&I, DAG.getVectorShuffle(VT, getCurDebugLoc(), Src1, Src2,
-                                      &MappedOps[0]));
-    return;
+  for (CaseItr I=Cases.begin(), E=Cases.end(); I!=E; ++I, ++numCmps) {
+    if (I->Low != I->High)
+      // A range counts double, since it requires two compares.
+      ++numCmps;
   }
 
-  if (SrcNumElts > MaskNumElts) {
-    // Analyze the access pattern of the vector to see if we can extract
-    // two subvectors and do the shuffle. The analysis is done by calculating
-    // the range of elements the mask access on both vectors.
-    int MinRange[2] = { SrcNumElts+1, SrcNumElts+1};
-    int MaxRange[2] = {-1, -1};
+  return numCmps;
+}
 
-    for (unsigned i = 0; i != MaskNumElts; ++i) {
-      int Idx = Mask[i];
-      int Input = 0;
-      if (Idx < 0)
-        continue;
+void SelectionDAGBuilder::visitSwitch(const SwitchInst &SI) {
+  MachineBasicBlock *SwitchMBB = FuncInfo.MBBMap[SI.getParent()];
 
-      if (Idx >= (int)SrcNumElts) {
-        Input = 1;
-        Idx -= SrcNumElts;
-      }
-      if (Idx > MaxRange[Input])
-        MaxRange[Input] = Idx;
-      if (Idx < MinRange[Input])
-        MinRange[Input] = Idx;
-    }
+  // Figure out which block is immediately after the current one.
+  MachineBasicBlock *NextBlock = 0;
+  MachineBasicBlock *Default = FuncInfo.MBBMap[SI.getDefaultDest()];
 
-    // Check if the access is smaller than the vector size and can we find
-    // a reasonable extract index.
-    int RangeUse[2] = { 2, 2 };  // 0 = Unused, 1 = Extract, 2 = Can not
-                                 // Extract.
-    int StartIdx[2];  // StartIdx to extract from
-    for (int Input=0; Input < 2; ++Input) {
-      if (MinRange[Input] == (int)(SrcNumElts+1) && MaxRange[Input] == -1) {
-        RangeUse[Input] = 0; // Unused
-        StartIdx[Input] = 0;
-      } else if (MaxRange[Input] - MinRange[Input] < (int)MaskNumElts) {
-        // Fits within range but we should see if we can find a good
-        // start index that is a multiple of the mask length.
-        if (MaxRange[Input] < (int)MaskNumElts) {
-          RangeUse[Input] = 1; // Extract from beginning of the vector
-          StartIdx[Input] = 0;
-        } else {
-          StartIdx[Input] = (MinRange[Input]/MaskNumElts)*MaskNumElts;
-          if (MaxRange[Input] - StartIdx[Input] < (int)MaskNumElts &&
-              StartIdx[Input] + MaskNumElts < SrcNumElts)
-            RangeUse[Input] = 1; // Extract from a multiple of the mask length.
-        }
-      }
-    }
-
-    if (RangeUse[0] == 0 && RangeUse[1] == 0) {
-      setValue(&I, DAG.getUNDEF(VT)); // Vectors are not used.
-      return;
-    }
-    else if (RangeUse[0] < 2 && RangeUse[1] < 2) {
-      // Extract appropriate subvector and generate a vector shuffle
-      for (int Input=0; Input < 2; ++Input) {
-        SDValue &Src = Input == 0 ? Src1 : Src2;
-        if (RangeUse[Input] == 0)
-          Src = DAG.getUNDEF(VT);
-        else
-          Src = DAG.getNode(ISD::EXTRACT_SUBVECTOR, getCurDebugLoc(), VT,
-                            Src, DAG.getIntPtrConstant(StartIdx[Input]));
-      }
+  // If there is only the default destination, branch to it if it is not the
+  // next basic block.  Otherwise, just fall through.
+  if (SI.getNumOperands() == 2) {
+    // Update machine-CFG edges.
 
-      // Calculate new mask.
-      SmallVector<int, 8> MappedOps;
-      for (unsigned i = 0; i != MaskNumElts; ++i) {
-        int Idx = Mask[i];
-        if (Idx < 0)
-          MappedOps.push_back(Idx);
-        else if (Idx < (int)SrcNumElts)
-          MappedOps.push_back(Idx - StartIdx[0]);
-        else
-          MappedOps.push_back(Idx - SrcNumElts - StartIdx[1] + MaskNumElts);
-      }
+    // If this is not a fall-through branch, emit the branch.
+    SwitchMBB->addSuccessor(Default);
+    if (Default != NextBlock)
+      DAG.setRoot(DAG.getNode(ISD::BR, getCurDebugLoc(),
+                              MVT::Other, getControlRoot(),
+                              DAG.getBasicBlock(Default)));
 
-      setValue(&I, DAG.getVectorShuffle(VT, getCurDebugLoc(), Src1, Src2,
-                                        &MappedOps[0]));
-      return;
-    }
+    return;
   }
 
-  // We can't use either concat vectors or extract subvectors so fall back to
-  // replacing the shuffle with extract and build vector.
-  // to insert and build vector.
-  EVT EltVT = VT.getVectorElementType();
-  EVT PtrVT = TLI.getPointerTy();
-  SmallVector<SDValue,8> Ops;
-  for (unsigned i = 0; i != MaskNumElts; ++i) {
-    if (Mask[i] < 0) {
-      Ops.push_back(DAG.getUNDEF(EltVT));
-    } else {
-      int Idx = Mask[i];
-      SDValue Res;
-
-      if (Idx < (int)SrcNumElts)
-        Res = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, getCurDebugLoc(),
-                          EltVT, Src1, DAG.getConstant(Idx, PtrVT));
-      else
-        Res = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, getCurDebugLoc(),
-                          EltVT, Src2,
-                          DAG.getConstant(Idx - SrcNumElts, PtrVT));
-
-      Ops.push_back(Res);
-    }
-  }
+  // If there are any non-default case statements, create a vector of Cases
+  // representing each one, and sort the vector so that we can efficiently
+  // create a binary search tree from them.
+  CaseVector Cases;
+  size_t numCmps = Clusterify(Cases, SI);
+  DEBUG(dbgs() << "Clusterify finished. Total clusters: " << Cases.size()
+               << ". Total compares: " << numCmps << '\n');
+  numCmps = 0;
 
-  setValue(&I, DAG.getNode(ISD::BUILD_VECTOR, getCurDebugLoc(),
-                           VT, &Ops[0], Ops.size()));
-}
+  // Get the Value to be switched on and default basic blocks, which will be
+  // inserted into CaseBlock records, representing basic blocks in the binary
+  // search tree.
+  const Value *SV = SI.getOperand(0);
 
-void SelectionDAGBuilder::visitInsertValue(const InsertValueInst &I) {
-  const Value *Op0 = I.getOperand(0);
-  const Value *Op1 = I.getOperand(1);
-  const Type *AggTy = I.getType();
-  const Type *ValTy = Op1->getType();
-  bool IntoUndef = isa<UndefValue>(Op0);
-  bool FromUndef = isa<UndefValue>(Op1);
+  // Push the initial CaseRec onto the worklist
+  CaseRecVector WorkList;
+  WorkList.push_back(CaseRec(SwitchMBB,0,0,
+                             CaseRange(Cases.begin(),Cases.end())));
 
-  unsigned LinearIndex = ComputeLinearIndex(TLI, AggTy,
-                                            I.idx_begin(), I.idx_end());
+  while (!WorkList.empty()) {
+    // Grab a record representing a case range to process off the worklist
+    CaseRec CR = WorkList.back();
+    WorkList.pop_back();
 
-  SmallVector<EVT, 4> AggValueVTs;
-  ComputeValueVTs(TLI, AggTy, AggValueVTs);
-  SmallVector<EVT, 4> ValValueVTs;
-  ComputeValueVTs(TLI, ValTy, ValValueVTs);
+    if (handleBitTestsSwitchCase(CR, WorkList, SV, Default, SwitchMBB))
+      continue;
 
-  unsigned NumAggValues = AggValueVTs.size();
-  unsigned NumValValues = ValValueVTs.size();
-  SmallVector<SDValue, 4> Values(NumAggValues);
+    // If the range has few cases (two or less) emit a series of specific
+    // tests.
+    if (handleSmallSwitchRange(CR, WorkList, SV, Default, SwitchMBB))
+      continue;
 
-  SDValue Agg = getValue(Op0);
-  SDValue Val = getValue(Op1);
-  unsigned i = 0;
-  // Copy the beginning value(s) from the original aggregate.
-  for (; i != LinearIndex; ++i)
-    Values[i] = IntoUndef ? DAG.getUNDEF(AggValueVTs[i]) :
-                SDValue(Agg.getNode(), Agg.getResNo() + i);
-  // Copy values from the inserted value(s).
-  for (; i != LinearIndex + NumValValues; ++i)
-    Values[i] = FromUndef ? DAG.getUNDEF(AggValueVTs[i]) :
-                SDValue(Val.getNode(), Val.getResNo() + i - LinearIndex);
-  // Copy remaining value(s) from the original aggregate.
-  for (; i != NumAggValues; ++i)
-    Values[i] = IntoUndef ? DAG.getUNDEF(AggValueVTs[i]) :
-                SDValue(Agg.getNode(), Agg.getResNo() + i);
+    // If the switch has more than 5 blocks, and at least 40% dense, and the
+    // target supports indirect branches, then emit a jump table rather than
+    // lowering the switch to a binary tree of conditional branches.
+    if (handleJTSwitchCase(CR, WorkList, SV, Default, SwitchMBB))
+      continue;
 
-  setValue(&I, DAG.getNode(ISD::MERGE_VALUES, getCurDebugLoc(),
-                           DAG.getVTList(&AggValueVTs[0], NumAggValues),
-                           &Values[0], NumAggValues));
+    // Emit binary tree. We need to pick a pivot, and push left and right ranges
+    // onto the worklist. Leafs are handled via handleSmallSwitchRange() call.
+    handleBTSplitSwitchCase(CR, WorkList, SV, Default, SwitchMBB);
+  }
 }
 
-void SelectionDAGBuilder::visitExtractValue(const ExtractValueInst &I) {
-  const Value *Op0 = I.getOperand(0);
-  const Type *AggTy = Op0->getType();
-  const Type *ValTy = I.getType();
-  bool OutOfUndef = isa<UndefValue>(Op0);
+void SelectionDAGBuilder::visitIndirectBr(const IndirectBrInst &I) {
+  MachineBasicBlock *IndirectBrMBB = FuncInfo.MBBMap[I.getParent()];
 
-  unsigned LinearIndex = ComputeLinearIndex(TLI, AggTy,
-                                            I.idx_begin(), I.idx_end());
+  // Update machine-CFG edges with unique successors.
+  SmallVector<BasicBlock*, 32> succs;
+  succs.reserve(I.getNumSuccessors());
+  for (unsigned i = 0, e = I.getNumSuccessors(); i != e; ++i)
+    succs.push_back(I.getSuccessor(i));
+  array_pod_sort(succs.begin(), succs.end());
+  succs.erase(std::unique(succs.begin(), succs.end()), succs.end());
+  for (unsigned i = 0, e = succs.size(); i != e; ++i)
+    IndirectBrMBB->addSuccessor(FuncInfo.MBBMap[succs[i]]);
 
-  SmallVector<EVT, 4> ValValueVTs;
-  ComputeValueVTs(TLI, ValTy, ValValueVTs);
+  DAG.setRoot(DAG.getNode(ISD::BRIND, getCurDebugLoc(),
+                          MVT::Other, getControlRoot(),
+                          getValue(I.getAddress())));
+}
 
-  unsigned NumValValues = ValValueVTs.size();
-  SmallVector<SDValue, 4> Values(NumValValues);
+void SelectionDAGBuilder::visitFSub(const User &I) {
+  // -0.0 - X --> fneg
+  const Type *Ty = I.getType();
+  if (Ty->isVectorTy()) {
+    if (ConstantVector *CV = dyn_cast<ConstantVector>(I.getOperand(0))) {
+      const VectorType *DestTy = cast<VectorType>(I.getType());
+      const Type *ElTy = DestTy->getElementType();
+      unsigned VL = DestTy->getNumElements();
+      std::vector<Constant*> NZ(VL, ConstantFP::getNegativeZero(ElTy));
+      Constant *CNZ = ConstantVector::get(&NZ[0], NZ.size());
+      if (CV == CNZ) {
+        SDValue Op2 = getValue(I.getOperand(1));
+        setValue(&I, DAG.getNode(ISD::FNEG, getCurDebugLoc(),
+                                 Op2.getValueType(), Op2));
+        return;
+      }
+    }
+  }
 
-  SDValue Agg = getValue(Op0);
-  // Copy out the selected value(s).
-  for (unsigned i = LinearIndex; i != LinearIndex + NumValValues; ++i)
-    Values[i - LinearIndex] =
-      OutOfUndef ?
-        DAG.getUNDEF(Agg.getNode()->getValueType(Agg.getResNo() + i)) :
-        SDValue(Agg.getNode(), Agg.getResNo() + i);
+  if (ConstantFP *CFP = dyn_cast<ConstantFP>(I.getOperand(0)))
+    if (CFP->isExactlyValue(ConstantFP::getNegativeZero(Ty)->getValueAPF())) {
+      SDValue Op2 = getValue(I.getOperand(1));
+      setValue(&I, DAG.getNode(ISD::FNEG, getCurDebugLoc(),
+                               Op2.getValueType(), Op2));
+      return;
+    }
 
-  setValue(&I, DAG.getNode(ISD::MERGE_VALUES, getCurDebugLoc(),
-                           DAG.getVTList(&ValValueVTs[0], NumValValues),
-                           &Values[0], NumValValues));
+  visitBinary(I, ISD::FSUB);
 }
 
-void SelectionDAGBuilder::visitGetElementPtr(const User &I) {
-  SDValue N = getValue(I.getOperand(0));
-  const Type *Ty = I.getOperand(0)->getType();
-
-  for (GetElementPtrInst::const_op_iterator OI = I.op_begin()+1, E = I.op_end();
-       OI != E; ++OI) {
-    const Value *Idx = *OI;
-    if (const StructType *StTy = dyn_cast<StructType>(Ty)) {
-      unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
-      if (Field) {
-        // N = N + Offset
-        uint64_t Offset = TD->getStructLayout(StTy)->getElementOffset(Field);
-        N = DAG.getNode(ISD::ADD, getCurDebugLoc(), N.getValueType(), N,
-                        DAG.getIntPtrConstant(Offset));
-      }
-
-      Ty = StTy->getElementType(Field);
-    } else if (const UnionType *UnTy = dyn_cast<UnionType>(Ty)) {
-      unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
-      
-      // Offset canonically 0 for unions, but type changes
-      Ty = UnTy->getElementType(Field);
-    } else {
-      Ty = cast<SequentialType>(Ty)->getElementType();
+void SelectionDAGBuilder::visitBinary(const User &I, unsigned OpCode) {
+  SDValue Op1 = getValue(I.getOperand(0));
+  SDValue Op2 = getValue(I.getOperand(1));
+  setValue(&I, DAG.getNode(OpCode, getCurDebugLoc(),
+                           Op1.getValueType(), Op1, Op2));
+}
 
-      // If this is a constant subscript, handle it quickly.
-      if (const ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
-        if (CI->getZExtValue() == 0) continue;
-        uint64_t Offs =
-            TD->getTypeAllocSize(Ty)*cast<ConstantInt>(CI)->getSExtValue();
-        SDValue OffsVal;
-        EVT PTy = TLI.getPointerTy();
-        unsigned PtrBits = PTy.getSizeInBits();
-        if (PtrBits < 64)
-          OffsVal = DAG.getNode(ISD::TRUNCATE, getCurDebugLoc(),
-                                TLI.getPointerTy(),
-                                DAG.getConstant(Offs, MVT::i64));
-        else
-          OffsVal = DAG.getIntPtrConstant(Offs);
-
-        N = DAG.getNode(ISD::ADD, getCurDebugLoc(), N.getValueType(), N,
-                        OffsVal);
-        continue;
-      }
-
-      // N = N + Idx * ElementSize;
-      APInt ElementSize = APInt(TLI.getPointerTy().getSizeInBits(),
-                                TD->getTypeAllocSize(Ty));
-      SDValue IdxN = getValue(Idx);
-
-      // If the index is smaller or larger than intptr_t, truncate or extend
-      // it.
-      IdxN = DAG.getSExtOrTrunc(IdxN, getCurDebugLoc(), N.getValueType());
-
-      // If this is a multiply by a power of two, turn it into a shl
-      // immediately.  This is a very common case.
-      if (ElementSize != 1) {
-        if (ElementSize.isPowerOf2()) {
-          unsigned Amt = ElementSize.logBase2();
-          IdxN = DAG.getNode(ISD::SHL, getCurDebugLoc(),
-                             N.getValueType(), IdxN,
-                             DAG.getConstant(Amt, TLI.getPointerTy()));
-        } else {
-          SDValue Scale = DAG.getConstant(ElementSize, TLI.getPointerTy());
-          IdxN = DAG.getNode(ISD::MUL, getCurDebugLoc(),
-                             N.getValueType(), IdxN, Scale);
-        }
-      }
-
-      N = DAG.getNode(ISD::ADD, getCurDebugLoc(),
-                      N.getValueType(), N, IdxN);
-    }
+void SelectionDAGBuilder::visitShift(const User &I, unsigned Opcode) {
+  SDValue Op1 = getValue(I.getOperand(0));
+  SDValue Op2 = getValue(I.getOperand(1));
+  if (!I.getType()->isVectorTy() &&
+      Op2.getValueType() != TLI.getShiftAmountTy()) {
+    // If the operand is smaller than the shift count type, promote it.
+    EVT PTy = TLI.getPointerTy();
+    EVT STy = TLI.getShiftAmountTy();
+    if (STy.bitsGT(Op2.getValueType()))
+      Op2 = DAG.getNode(ISD::ANY_EXTEND, getCurDebugLoc(),
+                        TLI.getShiftAmountTy(), Op2);
+    // If the operand is larger than the shift count type but the shift
+    // count type has enough bits to represent any shift value, truncate
+    // it now. This is a common case and it exposes the truncate to
+    // optimization early.
+    else if (STy.getSizeInBits() >=
+             Log2_32_Ceil(Op2.getValueType().getSizeInBits()))
+      Op2 = DAG.getNode(ISD::TRUNCATE, getCurDebugLoc(),
+                        TLI.getShiftAmountTy(), Op2);
+    // Otherwise we'll need to temporarily settle for some other
+    // convenient type; type legalization will make adjustments as
+    // needed.
+    else if (PTy.bitsLT(Op2.getValueType()))
+      Op2 = DAG.getNode(ISD::TRUNCATE, getCurDebugLoc(),
+                        TLI.getPointerTy(), Op2);
+    else if (PTy.bitsGT(Op2.getValueType()))
+      Op2 = DAG.getNode(ISD::ANY_EXTEND, getCurDebugLoc(),
+                        TLI.getPointerTy(), Op2);
   }
 
-  setValue(&I, N);
+  setValue(&I, DAG.getNode(Opcode, getCurDebugLoc(),
+                           Op1.getValueType(), Op1, Op2));
 }
 
-void SelectionDAGBuilder::visitAlloca(const AllocaInst &I) {
-  // If this is a fixed sized alloca in the entry block of the function,
-  // allocate it statically on the stack.
-  if (FuncInfo.StaticAllocaMap.count(&I))
-    return;   // getValue will auto-populate this.
-
-  const Type *Ty = I.getAllocatedType();
-  uint64_t TySize = TLI.getTargetData()->getTypeAllocSize(Ty);
-  unsigned Align =
-    std::max((unsigned)TLI.getTargetData()->getPrefTypeAlignment(Ty),
-             I.getAlignment());
-
-  SDValue AllocSize = getValue(I.getArraySize());
-
-  EVT IntPtr = TLI.getPointerTy();
-  if (AllocSize.getValueType() != IntPtr)
-    AllocSize = DAG.getZExtOrTrunc(AllocSize, getCurDebugLoc(), IntPtr);
-
-  AllocSize = DAG.getNode(ISD::MUL, getCurDebugLoc(), IntPtr,
-                          AllocSize,
-                          DAG.getConstant(TySize, IntPtr));
-
-  // Handle alignment.  If the requested alignment is less than or equal to
-  // the stack alignment, ignore it.  If the size is greater than or equal to
-  // the stack alignment, we note this in the DYNAMIC_STACKALLOC node.
-  unsigned StackAlign = TM.getFrameInfo()->getStackAlignment();
-  if (Align <= StackAlign)
-    Align = 0;
-
-  // Round the size of the allocation up to the stack alignment size
-  // by add SA-1 to the size.
-  AllocSize = DAG.getNode(ISD::ADD, getCurDebugLoc(),
-                          AllocSize.getValueType(), AllocSize,
-                          DAG.getIntPtrConstant(StackAlign-1));
-
-  // Mask out the low bits for alignment purposes.
-  AllocSize = DAG.getNode(ISD::AND, getCurDebugLoc(),
-                          AllocSize.getValueType(), AllocSize,
-                          DAG.getIntPtrConstant(~(uint64_t)(StackAlign-1)));
-
-  SDValue Ops[] = { getRoot(), AllocSize, DAG.getIntPtrConstant(Align) };
-  SDVTList VTs = DAG.getVTList(AllocSize.getValueType(), MVT::Other);
-  SDValue DSA = DAG.getNode(ISD::DYNAMIC_STACKALLOC, getCurDebugLoc(),
-                            VTs, Ops, 3);
-  setValue(&I, DSA);
-  DAG.setRoot(DSA.getValue(1));
+void SelectionDAGBuilder::visitICmp(const User &I) {
+  ICmpInst::Predicate predicate = ICmpInst::BAD_ICMP_PREDICATE;
+  if (const ICmpInst *IC = dyn_cast<ICmpInst>(&I))
+    predicate = IC->getPredicate();
+  else if (const ConstantExpr *IC = dyn_cast<ConstantExpr>(&I))
+    predicate = ICmpInst::Predicate(IC->getPredicate());
+  SDValue Op1 = getValue(I.getOperand(0));
+  SDValue Op2 = getValue(I.getOperand(1));
+  ISD::CondCode Opcode = getICmpCondCode(predicate);
 
-  // Inform the Frame Information that we have just allocated a variable-sized
-  // object.
-  FuncInfo.MF->getFrameInfo()->CreateVariableSizedObject();
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getSetCC(getCurDebugLoc(), DestVT, Op1, Op2, Opcode));
 }
 
-void SelectionDAGBuilder::visitLoad(const LoadInst &I) {
-  const Value *SV = I.getOperand(0);
-  SDValue Ptr = getValue(SV);
-
-  const Type *Ty = I.getType();
-
-  bool isVolatile = I.isVolatile();
-  bool isNonTemporal = I.getMetadata("nontemporal") != 0;
-  unsigned Alignment = I.getAlignment();
+void SelectionDAGBuilder::visitFCmp(const User &I) {
+  FCmpInst::Predicate predicate = FCmpInst::BAD_FCMP_PREDICATE;
+  if (const FCmpInst *FC = dyn_cast<FCmpInst>(&I))
+    predicate = FC->getPredicate();
+  else if (const ConstantExpr *FC = dyn_cast<ConstantExpr>(&I))
+    predicate = FCmpInst::Predicate(FC->getPredicate());
+  SDValue Op1 = getValue(I.getOperand(0));
+  SDValue Op2 = getValue(I.getOperand(1));
+  ISD::CondCode Condition = getFCmpCondCode(predicate);
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getSetCC(getCurDebugLoc(), DestVT, Op1, Op2, Condition));
+}
 
+void SelectionDAGBuilder::visitSelect(const User &I) {
   SmallVector<EVT, 4> ValueVTs;
-  SmallVector<uint64_t, 4> Offsets;
-  ComputeValueVTs(TLI, Ty, ValueVTs, &Offsets);
+  ComputeValueVTs(TLI, I.getType(), ValueVTs);
   unsigned NumValues = ValueVTs.size();
-  if (NumValues == 0)
-    return;
-
-  SDValue Root;
-  bool ConstantMemory = false;
-  if (I.isVolatile())
-    // Serialize volatile loads with other side effects.
-    Root = getRoot();
-  else if (AA->pointsToConstantMemory(SV)) {
-    // Do not serialize (non-volatile) loads of constant memory with anything.
-    Root = DAG.getEntryNode();
-    ConstantMemory = true;
-  } else {
-    // Do not serialize non-volatile loads against each other.
-    Root = DAG.getRoot();
-  }
+  if (NumValues == 0) return;
 
   SmallVector<SDValue, 4> Values(NumValues);
-  SmallVector<SDValue, 4> Chains(NumValues);
-  EVT PtrVT = Ptr.getValueType();
-  for (unsigned i = 0; i != NumValues; ++i) {
-    SDValue A = DAG.getNode(ISD::ADD, getCurDebugLoc(),
-                            PtrVT, Ptr,
-                            DAG.getConstant(Offsets[i], PtrVT));
-    SDValue L = DAG.getLoad(ValueVTs[i], getCurDebugLoc(), Root,
-                            A, SV, Offsets[i], isVolatile, 
-                            isNonTemporal, Alignment);
-
-    Values[i] = L;
-    Chains[i] = L.getValue(1);
-  }
+  SDValue Cond     = getValue(I.getOperand(0));
+  SDValue TrueVal  = getValue(I.getOperand(1));
+  SDValue FalseVal = getValue(I.getOperand(2));
 
-  if (!ConstantMemory) {
-    SDValue Chain = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(),
-                                MVT::Other, &Chains[0], NumValues);
-    if (isVolatile)
-      DAG.setRoot(Chain);
-    else
-      PendingLoads.push_back(Chain);
-  }
+  for (unsigned i = 0; i != NumValues; ++i)
+    Values[i] = DAG.getNode(ISD::SELECT, getCurDebugLoc(),
+                          TrueVal.getNode()->getValueType(TrueVal.getResNo()+i),
+                            Cond,
+                            SDValue(TrueVal.getNode(),
+                                    TrueVal.getResNo() + i),
+                            SDValue(FalseVal.getNode(),
+                                    FalseVal.getResNo() + i));
 
   setValue(&I, DAG.getNode(ISD::MERGE_VALUES, getCurDebugLoc(),
                            DAG.getVTList(&ValueVTs[0], NumValues),
                            &Values[0], NumValues));
 }
 
-void SelectionDAGBuilder::visitStore(const StoreInst &I) {
-  const Value *SrcV = I.getOperand(0);
-  const Value *PtrV = I.getOperand(1);
+void SelectionDAGBuilder::visitTrunc(const User &I) {
+  // TruncInst cannot be a no-op cast because sizeof(src) > sizeof(dest).
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getNode(ISD::TRUNCATE, getCurDebugLoc(), DestVT, N));
+}
 
-  SmallVector<EVT, 4> ValueVTs;
-  SmallVector<uint64_t, 4> Offsets;
-  ComputeValueVTs(TLI, SrcV->getType(), ValueVTs, &Offsets);
-  unsigned NumValues = ValueVTs.size();
-  if (NumValues == 0)
-    return;
+void SelectionDAGBuilder::visitZExt(const User &I) {
+  // ZExt cannot be a no-op cast because sizeof(src) < sizeof(dest).
+  // ZExt also can't be a cast to bool for same reason. So, nothing much to do
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getNode(ISD::ZERO_EXTEND, getCurDebugLoc(), DestVT, N));
+}
 
-  // Get the lowered operands. Note that we do this after
-  // checking if NumResults is zero, because with zero results
-  // the operands won't have values in the map.
-  SDValue Src = getValue(SrcV);
-  SDValue Ptr = getValue(PtrV);
+void SelectionDAGBuilder::visitSExt(const User &I) {
+  // SExt cannot be a no-op cast because sizeof(src) < sizeof(dest).
+  // SExt also can't be a cast to bool for same reason. So, nothing much to do
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getNode(ISD::SIGN_EXTEND, getCurDebugLoc(), DestVT, N));
+}
 
-  SDValue Root = getRoot();
-  SmallVector<SDValue, 4> Chains(NumValues);
-  EVT PtrVT = Ptr.getValueType();
-  bool isVolatile = I.isVolatile();
-  bool isNonTemporal = I.getMetadata("nontemporal") != 0;
-  unsigned Alignment = I.getAlignment();
+void SelectionDAGBuilder::visitFPTrunc(const User &I) {
+  // FPTrunc is never a no-op cast, no need to check
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getNode(ISD::FP_ROUND, getCurDebugLoc(),
+                           DestVT, N, DAG.getIntPtrConstant(0)));
+}
 
-  for (unsigned i = 0; i != NumValues; ++i) {
-    SDValue Add = DAG.getNode(ISD::ADD, getCurDebugLoc(), PtrVT, Ptr,
-                              DAG.getConstant(Offsets[i], PtrVT));
-    Chains[i] = DAG.getStore(Root, getCurDebugLoc(),
-                             SDValue(Src.getNode(), Src.getResNo() + i),
-                             Add, PtrV, Offsets[i], isVolatile, 
-                             isNonTemporal, Alignment);
-  }
-
-  DAG.setRoot(DAG.getNode(ISD::TokenFactor, getCurDebugLoc(),
-                          MVT::Other, &Chains[0], NumValues));
+void SelectionDAGBuilder::visitFPExt(const User &I){
+  // FPTrunc is never a no-op cast, no need to check
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getNode(ISD::FP_EXTEND, getCurDebugLoc(), DestVT, N));
 }
 
-/// visitTargetIntrinsic - Lower a call of a target intrinsic to an INTRINSIC
-/// node.
-void SelectionDAGBuilder::visitTargetIntrinsic(const CallInst &I,
-                                               unsigned Intrinsic) {
-  bool HasChain = !I.doesNotAccessMemory();
-  bool OnlyLoad = HasChain && I.onlyReadsMemory();
-
-  // Build the operand list.
-  SmallVector<SDValue, 8> Ops;
-  if (HasChain) {  // If this intrinsic has side-effects, chainify it.
-    if (OnlyLoad) {
-      // We don't need to serialize loads against other loads.
-      Ops.push_back(DAG.getRoot());
-    } else {
-      Ops.push_back(getRoot());
-    }
-  }
-
-  // Info is set by getTgtMemInstrinsic
-  TargetLowering::IntrinsicInfo Info;
-  bool IsTgtIntrinsic = TLI.getTgtMemIntrinsic(Info, I, Intrinsic);
-
-  // Add the intrinsic ID as an integer operand if it's not a target intrinsic.
-  if (!IsTgtIntrinsic)
-    Ops.push_back(DAG.getConstant(Intrinsic, TLI.getPointerTy()));
-
-  // Add all operands of the call to the operand list.
-  for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i) {
-    SDValue Op = getValue(I.getOperand(i));
-    assert(TLI.isTypeLegal(Op.getValueType()) &&
-           "Intrinsic uses a non-legal type?");
-    Ops.push_back(Op);
-  }
+void SelectionDAGBuilder::visitFPToUI(const User &I) {
+  // FPToUI is never a no-op cast, no need to check
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getNode(ISD::FP_TO_UINT, getCurDebugLoc(), DestVT, N));
+}
 
-  SmallVector<EVT, 4> ValueVTs;
-  ComputeValueVTs(TLI, I.getType(), ValueVTs);
-#ifndef NDEBUG
-  for (unsigned Val = 0, E = ValueVTs.size(); Val != E; ++Val) {
-    assert(TLI.isTypeLegal(ValueVTs[Val]) &&
-           "Intrinsic uses a non-legal type?");
-  }
-#endif // NDEBUG
+void SelectionDAGBuilder::visitFPToSI(const User &I) {
+  // FPToSI is never a no-op cast, no need to check
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getNode(ISD::FP_TO_SINT, getCurDebugLoc(), DestVT, N));
+}
 
-  if (HasChain)
-    ValueVTs.push_back(MVT::Other);
+void SelectionDAGBuilder::visitUIToFP(const User &I) {
+  // UIToFP is never a no-op cast, no need to check
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getNode(ISD::UINT_TO_FP, getCurDebugLoc(), DestVT, N));
+}
 
-  SDVTList VTs = DAG.getVTList(ValueVTs.data(), ValueVTs.size());
+void SelectionDAGBuilder::visitSIToFP(const User &I){
+  // SIToFP is never a no-op cast, no need to check
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getNode(ISD::SINT_TO_FP, getCurDebugLoc(), DestVT, N));
+}
 
-  // Create the node.
-  SDValue Result;
-  if (IsTgtIntrinsic) {
-    // This is target intrinsic that touches memory
-    Result = DAG.getMemIntrinsicNode(Info.opc, getCurDebugLoc(),
-                                     VTs, &Ops[0], Ops.size(),
-                                     Info.memVT, Info.ptrVal, Info.offset,
-                                     Info.align, Info.vol,
-                                     Info.readMem, Info.writeMem);
-  } else if (!HasChain) {
-    Result = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, getCurDebugLoc(),
-                         VTs, &Ops[0], Ops.size());
-  } else if (!I.getType()->isVoidTy()) {
-    Result = DAG.getNode(ISD::INTRINSIC_W_CHAIN, getCurDebugLoc(),
-                         VTs, &Ops[0], Ops.size());
-  } else {
-    Result = DAG.getNode(ISD::INTRINSIC_VOID, getCurDebugLoc(),
-                         VTs, &Ops[0], Ops.size());
-  }
+void SelectionDAGBuilder::visitPtrToInt(const User &I) {
+  // What to do depends on the size of the integer and the size of the pointer.
+  // We can either truncate, zero extend, or no-op, accordingly.
+  SDValue N = getValue(I.getOperand(0));
+  EVT SrcVT = N.getValueType();
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getZExtOrTrunc(N, getCurDebugLoc(), DestVT));
+}
 
-  if (HasChain) {
-    SDValue Chain = Result.getValue(Result.getNode()->getNumValues()-1);
-    if (OnlyLoad)
-      PendingLoads.push_back(Chain);
-    else
-      DAG.setRoot(Chain);
-  }
+void SelectionDAGBuilder::visitIntToPtr(const User &I) {
+  // What to do depends on the size of the integer and the size of the pointer.
+  // We can either truncate, zero extend, or no-op, accordingly.
+  SDValue N = getValue(I.getOperand(0));
+  EVT SrcVT = N.getValueType();
+  EVT DestVT = TLI.getValueType(I.getType());
+  setValue(&I, DAG.getZExtOrTrunc(N, getCurDebugLoc(), DestVT));
+}
 
-  if (!I.getType()->isVoidTy()) {
-    if (const VectorType *PTy = dyn_cast<VectorType>(I.getType())) {
-      EVT VT = TLI.getValueType(PTy);
-      Result = DAG.getNode(ISD::BIT_CONVERT, getCurDebugLoc(), VT, Result);
-    }
+void SelectionDAGBuilder::visitBitCast(const User &I) {
+  SDValue N = getValue(I.getOperand(0));
+  EVT DestVT = TLI.getValueType(I.getType());
 
-    setValue(&I, Result);
-  }
+  // BitCast assures us that source and destination are the same size so this is
+  // either a BIT_CONVERT or a no-op.
+  if (DestVT != N.getValueType())
+    setValue(&I, DAG.getNode(ISD::BIT_CONVERT, getCurDebugLoc(),
+                             DestVT, N)); // convert types.
+  else
+    setValue(&I, N);            // noop cast.
 }
 
-/// GetSignificand - Get the significand and build it into a floating-point
-/// number with exponent of 1:
-///
-///   Op = (Op & 0x007fffff) | 0x3f800000;
-///
-/// where Op is the hexidecimal representation of floating point value.
-static SDValue
-GetSignificand(SelectionDAG &DAG, SDValue Op, DebugLoc dl) {
-  SDValue t1 = DAG.getNode(ISD::AND, dl, MVT::i32, Op,
-                           DAG.getConstant(0x007fffff, MVT::i32));
-  SDValue t2 = DAG.getNode(ISD::OR, dl, MVT::i32, t1,
-                           DAG.getConstant(0x3f800000, MVT::i32));
-  return DAG.getNode(ISD::BIT_CONVERT, dl, MVT::f32, t2);
+void SelectionDAGBuilder::visitInsertElement(const User &I) {
+  SDValue InVec = getValue(I.getOperand(0));
+  SDValue InVal = getValue(I.getOperand(1));
+  SDValue InIdx = DAG.getNode(ISD::ZERO_EXTEND, getCurDebugLoc(),
+                              TLI.getPointerTy(),
+                              getValue(I.getOperand(2)));
+  setValue(&I, DAG.getNode(ISD::INSERT_VECTOR_ELT, getCurDebugLoc(),
+                           TLI.getValueType(I.getType()),
+                           InVec, InVal, InIdx));
 }
 
-/// GetExponent - Get the exponent:
-///
-///   (float)(int)(((Op & 0x7f800000) >> 23) - 127);
-///
-/// where Op is the hexidecimal representation of floating point value.
-static SDValue
-GetExponent(SelectionDAG &DAG, SDValue Op, const TargetLowering &TLI,
-            DebugLoc dl) {
-  SDValue t0 = DAG.getNode(ISD::AND, dl, MVT::i32, Op,
-                           DAG.getConstant(0x7f800000, MVT::i32));
-  SDValue t1 = DAG.getNode(ISD::SRL, dl, MVT::i32, t0,
-                           DAG.getConstant(23, TLI.getPointerTy()));
-  SDValue t2 = DAG.getNode(ISD::SUB, dl, MVT::i32, t1,
-                           DAG.getConstant(127, MVT::i32));
-  return DAG.getNode(ISD::SINT_TO_FP, dl, MVT::f32, t2);
+void SelectionDAGBuilder::visitExtractElement(const User &I) {
+  SDValue InVec = getValue(I.getOperand(0));
+  SDValue InIdx = DAG.getNode(ISD::ZERO_EXTEND, getCurDebugLoc(),
+                              TLI.getPointerTy(),
+                              getValue(I.getOperand(1)));
+  setValue(&I, DAG.getNode(ISD::EXTRACT_VECTOR_ELT, getCurDebugLoc(),
+                           TLI.getValueType(I.getType()), InVec, InIdx));
 }
 
-/// getF32Constant - Get 32-bit floating point constant.
-static SDValue
-getF32Constant(SelectionDAG &DAG, unsigned Flt) {
-  return DAG.getConstantFP(APFloat(APInt(32, Flt)), MVT::f32);
+// Utility for visitShuffleVector - Returns true if the mask is mask starting
+// from SIndx and increasing to the element length (undefs are allowed).
+static bool SequentialMask(SmallVectorImpl<int> &Mask, unsigned SIndx) {
+  unsigned MaskNumElts = Mask.size();
+  for (unsigned i = 0; i != MaskNumElts; ++i)
+    if ((Mask[i] >= 0) && (Mask[i] != (int)(i + SIndx)))
+      return false;
+  return true;
 }
 
-/// Inlined utility function to implement binary input atomic intrinsics for
-/// visitIntrinsicCall: I is a call instruction
-///                     Op is the associated NodeType for I
-const char *
-SelectionDAGBuilder::implVisitBinaryAtomic(const CallInst& I,
-                                           ISD::NodeType Op) {
-  SDValue Root = getRoot();
-  SDValue L =
-    DAG.getAtomic(Op, getCurDebugLoc(),
-                  getValue(I.getOperand(2)).getValueType().getSimpleVT(),
-                  Root,
-                  getValue(I.getOperand(1)),
-                  getValue(I.getOperand(2)),
-                  I.getOperand(1));
-  setValue(&I, L);
-  DAG.setRoot(L.getValue(1));
-  return 0;
-}
+void SelectionDAGBuilder::visitShuffleVector(const User &I) {
+  SmallVector<int, 8> Mask;
+  SDValue Src1 = getValue(I.getOperand(0));
+  SDValue Src2 = getValue(I.getOperand(1));
 
-// implVisitAluOverflow - Lower arithmetic overflow instrinsics.
-const char *
-SelectionDAGBuilder::implVisitAluOverflow(const CallInst &I, ISD::NodeType Op) {
-  SDValue Op1 = getValue(I.getOperand(1));
-  SDValue Op2 = getValue(I.getOperand(2));
+  // Convert the ConstantVector mask operand into an array of ints, with -1
+  // representing undef values.
+  SmallVector<Constant*, 8> MaskElts;
+  cast<Constant>(I.getOperand(2))->getVectorElements(MaskElts);
+  unsigned MaskNumElts = MaskElts.size();
+  for (unsigned i = 0; i != MaskNumElts; ++i) {
+    if (isa<UndefValue>(MaskElts[i]))
+      Mask.push_back(-1);
+    else
+      Mask.push_back(cast<ConstantInt>(MaskElts[i])->getSExtValue());
+  }
 
-  SDVTList VTs = DAG.getVTList(Op1.getValueType(), MVT::i1);
-  setValue(&I, DAG.getNode(Op, getCurDebugLoc(), VTs, Op1, Op2));
-  return 0;
-}
+  EVT VT = TLI.getValueType(I.getType());
+  EVT SrcVT = Src1.getValueType();
+  unsigned SrcNumElts = SrcVT.getVectorNumElements();
 
-/// visitExp - Lower an exp intrinsic. Handles the special sequences for
-/// limited-precision mode.
-void
-SelectionDAGBuilder::visitExp(const CallInst &I) {
-  SDValue result;
-  DebugLoc dl = getCurDebugLoc();
+  if (SrcNumElts == MaskNumElts) {
+    setValue(&I, DAG.getVectorShuffle(VT, getCurDebugLoc(), Src1, Src2,
+                                      &Mask[0]));
+    return;
+  }
 
-  if (getValue(I.getOperand(1)).getValueType() == MVT::f32 &&
-      LimitFloatPrecision > 0 && LimitFloatPrecision <= 18) {
+  // Normalize the shuffle vector since mask and vector length don't match.
+  if (SrcNumElts < MaskNumElts && MaskNumElts % SrcNumElts == 0) {
+    // Mask is longer than the source vectors and is a multiple of the source
+    // vectors.  We can use concatenate vector to make the mask and vectors
+    // lengths match.
+    if (SrcNumElts*2 == MaskNumElts && SequentialMask(Mask, 0)) {
+      // The shuffle is concatenating two vectors together.
+      setValue(&I, DAG.getNode(ISD::CONCAT_VECTORS, getCurDebugLoc(),
+                               VT, Src1, Src2));
+      return;
+    }
+
+    // Pad both vectors with undefs to make them the same length as the mask.
+    unsigned NumConcat = MaskNumElts / SrcNumElts;
+    bool Src1U = Src1.getOpcode() == ISD::UNDEF;
+    bool Src2U = Src2.getOpcode() == ISD::UNDEF;
+    SDValue UndefVal = DAG.getUNDEF(SrcVT);
+
+    SmallVector<SDValue, 8> MOps1(NumConcat, UndefVal);
+    SmallVector<SDValue, 8> MOps2(NumConcat, UndefVal);
+    MOps1[0] = Src1;
+    MOps2[0] = Src2;
+
+    Src1 = Src1U ? DAG.getUNDEF(VT) : DAG.getNode(ISD::CONCAT_VECTORS,
+                                                  getCurDebugLoc(), VT,
+                                                  &MOps1[0], NumConcat);
+    Src2 = Src2U ? DAG.getUNDEF(VT) : DAG.getNode(ISD::CONCAT_VECTORS,
+                                                  getCurDebugLoc(), VT,
+                                                  &MOps2[0], NumConcat);
+
+    // Readjust mask for new input vector length.
+    SmallVector<int, 8> MappedOps;
+    for (unsigned i = 0; i != MaskNumElts; ++i) {
+      int Idx = Mask[i];
+      if (Idx < (int)SrcNumElts)
+        MappedOps.push_back(Idx);
+      else
+        MappedOps.push_back(Idx + MaskNumElts - SrcNumElts);
+    }
+
+    setValue(&I, DAG.getVectorShuffle(VT, getCurDebugLoc(), Src1, Src2,
+                                      &MappedOps[0]));
+    return;
+  }
+
+  if (SrcNumElts > MaskNumElts) {
+    // Analyze the access pattern of the vector to see if we can extract
+    // two subvectors and do the shuffle. The analysis is done by calculating
+    // the range of elements the mask access on both vectors.
+    int MinRange[2] = { SrcNumElts+1, SrcNumElts+1};
+    int MaxRange[2] = {-1, -1};
+
+    for (unsigned i = 0; i != MaskNumElts; ++i) {
+      int Idx = Mask[i];
+      int Input = 0;
+      if (Idx < 0)
+        continue;
+
+      if (Idx >= (int)SrcNumElts) {
+        Input = 1;
+        Idx -= SrcNumElts;
+      }
+      if (Idx > MaxRange[Input])
+        MaxRange[Input] = Idx;
+      if (Idx < MinRange[Input])
+        MinRange[Input] = Idx;
+    }
+
+    // Check if the access is smaller than the vector size and can we find
+    // a reasonable extract index.
+    int RangeUse[2] = { 2, 2 };  // 0 = Unused, 1 = Extract, 2 = Can not
+                                 // Extract.
+    int StartIdx[2];  // StartIdx to extract from
+    for (int Input=0; Input < 2; ++Input) {
+      if (MinRange[Input] == (int)(SrcNumElts+1) && MaxRange[Input] == -1) {
+        RangeUse[Input] = 0; // Unused
+        StartIdx[Input] = 0;
+      } else if (MaxRange[Input] - MinRange[Input] < (int)MaskNumElts) {
+        // Fits within range but we should see if we can find a good
+        // start index that is a multiple of the mask length.
+        if (MaxRange[Input] < (int)MaskNumElts) {
+          RangeUse[Input] = 1; // Extract from beginning of the vector
+          StartIdx[Input] = 0;
+        } else {
+          StartIdx[Input] = (MinRange[Input]/MaskNumElts)*MaskNumElts;
+          if (MaxRange[Input] - StartIdx[Input] < (int)MaskNumElts &&
+              StartIdx[Input] + MaskNumElts < SrcNumElts)
+            RangeUse[Input] = 1; // Extract from a multiple of the mask length.
+        }
+      }
+    }
+
+    if (RangeUse[0] == 0 && RangeUse[1] == 0) {
+      setValue(&I, DAG.getUNDEF(VT)); // Vectors are not used.
+      return;
+    }
+    else if (RangeUse[0] < 2 && RangeUse[1] < 2) {
+      // Extract appropriate subvector and generate a vector shuffle
+      for (int Input=0; Input < 2; ++Input) {
+        SDValue &Src = Input == 0 ? Src1 : Src2;
+        if (RangeUse[Input] == 0)
+          Src = DAG.getUNDEF(VT);
+        else
+          Src = DAG.getNode(ISD::EXTRACT_SUBVECTOR, getCurDebugLoc(), VT,
+                            Src, DAG.getIntPtrConstant(StartIdx[Input]));
+      }
+
+      // Calculate new mask.
+      SmallVector<int, 8> MappedOps;
+      for (unsigned i = 0; i != MaskNumElts; ++i) {
+        int Idx = Mask[i];
+        if (Idx < 0)
+          MappedOps.push_back(Idx);
+        else if (Idx < (int)SrcNumElts)
+          MappedOps.push_back(Idx - StartIdx[0]);
+        else
+          MappedOps.push_back(Idx - SrcNumElts - StartIdx[1] + MaskNumElts);
+      }
+
+      setValue(&I, DAG.getVectorShuffle(VT, getCurDebugLoc(), Src1, Src2,
+                                        &MappedOps[0]));
+      return;
+    }
+  }
+
+  // We can't use either concat vectors or extract subvectors so fall back to
+  // replacing the shuffle with extract and build vector.
+  // to insert and build vector.
+  EVT EltVT = VT.getVectorElementType();
+  EVT PtrVT = TLI.getPointerTy();
+  SmallVector<SDValue,8> Ops;
+  for (unsigned i = 0; i != MaskNumElts; ++i) {
+    if (Mask[i] < 0) {
+      Ops.push_back(DAG.getUNDEF(EltVT));
+    } else {
+      int Idx = Mask[i];
+      SDValue Res;
+
+      if (Idx < (int)SrcNumElts)
+        Res = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, getCurDebugLoc(),
+                          EltVT, Src1, DAG.getConstant(Idx, PtrVT));
+      else
+        Res = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, getCurDebugLoc(),
+                          EltVT, Src2,
+                          DAG.getConstant(Idx - SrcNumElts, PtrVT));
+
+      Ops.push_back(Res);
+    }
+  }
+
+  setValue(&I, DAG.getNode(ISD::BUILD_VECTOR, getCurDebugLoc(),
+                           VT, &Ops[0], Ops.size()));
+}
+
+void SelectionDAGBuilder::visitInsertValue(const InsertValueInst &I) {
+  const Value *Op0 = I.getOperand(0);
+  const Value *Op1 = I.getOperand(1);
+  const Type *AggTy = I.getType();
+  const Type *ValTy = Op1->getType();
+  bool IntoUndef = isa<UndefValue>(Op0);
+  bool FromUndef = isa<UndefValue>(Op1);
+
+  unsigned LinearIndex = ComputeLinearIndex(TLI, AggTy,
+                                            I.idx_begin(), I.idx_end());
+
+  SmallVector<EVT, 4> AggValueVTs;
+  ComputeValueVTs(TLI, AggTy, AggValueVTs);
+  SmallVector<EVT, 4> ValValueVTs;
+  ComputeValueVTs(TLI, ValTy, ValValueVTs);
+
+  unsigned NumAggValues = AggValueVTs.size();
+  unsigned NumValValues = ValValueVTs.size();
+  SmallVector<SDValue, 4> Values(NumAggValues);
+
+  SDValue Agg = getValue(Op0);
+  SDValue Val = getValue(Op1);
+  unsigned i = 0;
+  // Copy the beginning value(s) from the original aggregate.
+  for (; i != LinearIndex; ++i)
+    Values[i] = IntoUndef ? DAG.getUNDEF(AggValueVTs[i]) :
+                SDValue(Agg.getNode(), Agg.getResNo() + i);
+  // Copy values from the inserted value(s).
+  for (; i != LinearIndex + NumValValues; ++i)
+    Values[i] = FromUndef ? DAG.getUNDEF(AggValueVTs[i]) :
+                SDValue(Val.getNode(), Val.getResNo() + i - LinearIndex);
+  // Copy remaining value(s) from the original aggregate.
+  for (; i != NumAggValues; ++i)
+    Values[i] = IntoUndef ? DAG.getUNDEF(AggValueVTs[i]) :
+                SDValue(Agg.getNode(), Agg.getResNo() + i);
+
+  setValue(&I, DAG.getNode(ISD::MERGE_VALUES, getCurDebugLoc(),
+                           DAG.getVTList(&AggValueVTs[0], NumAggValues),
+                           &Values[0], NumAggValues));
+}
+
+void SelectionDAGBuilder::visitExtractValue(const ExtractValueInst &I) {
+  const Value *Op0 = I.getOperand(0);
+  const Type *AggTy = Op0->getType();
+  const Type *ValTy = I.getType();
+  bool OutOfUndef = isa<UndefValue>(Op0);
+
+  unsigned LinearIndex = ComputeLinearIndex(TLI, AggTy,
+                                            I.idx_begin(), I.idx_end());
+
+  SmallVector<EVT, 4> ValValueVTs;
+  ComputeValueVTs(TLI, ValTy, ValValueVTs);
+
+  unsigned NumValValues = ValValueVTs.size();
+  SmallVector<SDValue, 4> Values(NumValValues);
+
+  SDValue Agg = getValue(Op0);
+  // Copy out the selected value(s).
+  for (unsigned i = LinearIndex; i != LinearIndex + NumValValues; ++i)
+    Values[i - LinearIndex] =
+      OutOfUndef ?
+        DAG.getUNDEF(Agg.getNode()->getValueType(Agg.getResNo() + i)) :
+        SDValue(Agg.getNode(), Agg.getResNo() + i);
+
+  setValue(&I, DAG.getNode(ISD::MERGE_VALUES, getCurDebugLoc(),
+                           DAG.getVTList(&ValValueVTs[0], NumValValues),
+                           &Values[0], NumValValues));
+}
+
+void SelectionDAGBuilder::visitGetElementPtr(const User &I) {
+  SDValue N = getValue(I.getOperand(0));
+  const Type *Ty = I.getOperand(0)->getType();
+
+  for (GetElementPtrInst::const_op_iterator OI = I.op_begin()+1, E = I.op_end();
+       OI != E; ++OI) {
+    const Value *Idx = *OI;
+    if (const StructType *StTy = dyn_cast<StructType>(Ty)) {
+      unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
+      if (Field) {
+        // N = N + Offset
+        uint64_t Offset = TD->getStructLayout(StTy)->getElementOffset(Field);
+        N = DAG.getNode(ISD::ADD, getCurDebugLoc(), N.getValueType(), N,
+                        DAG.getIntPtrConstant(Offset));
+      }
+
+      Ty = StTy->getElementType(Field);
+    } else if (const UnionType *UnTy = dyn_cast<UnionType>(Ty)) {
+      unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
+      
+      // Offset canonically 0 for unions, but type changes
+      Ty = UnTy->getElementType(Field);
+    } else {
+      Ty = cast<SequentialType>(Ty)->getElementType();
+
+      // If this is a constant subscript, handle it quickly.
+      if (const ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
+        if (CI->getZExtValue() == 0) continue;
+        uint64_t Offs =
+            TD->getTypeAllocSize(Ty)*cast<ConstantInt>(CI)->getSExtValue();
+        SDValue OffsVal;
+        EVT PTy = TLI.getPointerTy();
+        unsigned PtrBits = PTy.getSizeInBits();
+        if (PtrBits < 64)
+          OffsVal = DAG.getNode(ISD::TRUNCATE, getCurDebugLoc(),
+                                TLI.getPointerTy(),
+                                DAG.getConstant(Offs, MVT::i64));
+        else
+          OffsVal = DAG.getIntPtrConstant(Offs);
+
+        N = DAG.getNode(ISD::ADD, getCurDebugLoc(), N.getValueType(), N,
+                        OffsVal);
+        continue;
+      }
+
+      // N = N + Idx * ElementSize;
+      APInt ElementSize = APInt(TLI.getPointerTy().getSizeInBits(),
+                                TD->getTypeAllocSize(Ty));
+      SDValue IdxN = getValue(Idx);
+
+      // If the index is smaller or larger than intptr_t, truncate or extend
+      // it.
+      IdxN = DAG.getSExtOrTrunc(IdxN, getCurDebugLoc(), N.getValueType());
+
+      // If this is a multiply by a power of two, turn it into a shl
+      // immediately.  This is a very common case.
+      if (ElementSize != 1) {
+        if (ElementSize.isPowerOf2()) {
+          unsigned Amt = ElementSize.logBase2();
+          IdxN = DAG.getNode(ISD::SHL, getCurDebugLoc(),
+                             N.getValueType(), IdxN,
+                             DAG.getConstant(Amt, TLI.getPointerTy()));
+        } else {
+          SDValue Scale = DAG.getConstant(ElementSize, TLI.getPointerTy());
+          IdxN = DAG.getNode(ISD::MUL, getCurDebugLoc(),
+                             N.getValueType(), IdxN, Scale);
+        }
+      }
+
+      N = DAG.getNode(ISD::ADD, getCurDebugLoc(),
+                      N.getValueType(), N, IdxN);
+    }
+  }
+
+  setValue(&I, N);
+}
+
+void SelectionDAGBuilder::visitAlloca(const AllocaInst &I) {
+  // If this is a fixed sized alloca in the entry block of the function,
+  // allocate it statically on the stack.
+  if (FuncInfo.StaticAllocaMap.count(&I))
+    return;   // getValue will auto-populate this.
+
+  const Type *Ty = I.getAllocatedType();
+  uint64_t TySize = TLI.getTargetData()->getTypeAllocSize(Ty);
+  unsigned Align =
+    std::max((unsigned)TLI.getTargetData()->getPrefTypeAlignment(Ty),
+             I.getAlignment());
+
+  SDValue AllocSize = getValue(I.getArraySize());
+
+  EVT IntPtr = TLI.getPointerTy();
+  if (AllocSize.getValueType() != IntPtr)
+    AllocSize = DAG.getZExtOrTrunc(AllocSize, getCurDebugLoc(), IntPtr);
+
+  AllocSize = DAG.getNode(ISD::MUL, getCurDebugLoc(), IntPtr,
+                          AllocSize,
+                          DAG.getConstant(TySize, IntPtr));
+
+  // Handle alignment.  If the requested alignment is less than or equal to
+  // the stack alignment, ignore it.  If the size is greater than or equal to
+  // the stack alignment, we note this in the DYNAMIC_STACKALLOC node.
+  unsigned StackAlign = TM.getFrameInfo()->getStackAlignment();
+  if (Align <= StackAlign)
+    Align = 0;
+
+  // Round the size of the allocation up to the stack alignment size
+  // by add SA-1 to the size.
+  AllocSize = DAG.getNode(ISD::ADD, getCurDebugLoc(),
+                          AllocSize.getValueType(), AllocSize,
+                          DAG.getIntPtrConstant(StackAlign-1));
+
+  // Mask out the low bits for alignment purposes.
+  AllocSize = DAG.getNode(ISD::AND, getCurDebugLoc(),
+                          AllocSize.getValueType(), AllocSize,
+                          DAG.getIntPtrConstant(~(uint64_t)(StackAlign-1)));
+
+  SDValue Ops[] = { getRoot(), AllocSize, DAG.getIntPtrConstant(Align) };
+  SDVTList VTs = DAG.getVTList(AllocSize.getValueType(), MVT::Other);
+  SDValue DSA = DAG.getNode(ISD::DYNAMIC_STACKALLOC, getCurDebugLoc(),
+                            VTs, Ops, 3);
+  setValue(&I, DSA);
+  DAG.setRoot(DSA.getValue(1));
+
+  // Inform the Frame Information that we have just allocated a variable-sized
+  // object.
+  FuncInfo.MF->getFrameInfo()->CreateVariableSizedObject();
+}
+
+void SelectionDAGBuilder::visitLoad(const LoadInst &I) {
+  const Value *SV = I.getOperand(0);
+  SDValue Ptr = getValue(SV);
+
+  const Type *Ty = I.getType();
+
+  bool isVolatile = I.isVolatile();
+  bool isNonTemporal = I.getMetadata("nontemporal") != 0;
+  unsigned Alignment = I.getAlignment();
+
+  SmallVector<EVT, 4> ValueVTs;
+  SmallVector<uint64_t, 4> Offsets;
+  ComputeValueVTs(TLI, Ty, ValueVTs, &Offsets);
+  unsigned NumValues = ValueVTs.size();
+  if (NumValues == 0)
+    return;
+
+  SDValue Root;
+  bool ConstantMemory = false;
+  if (I.isVolatile())
+    // Serialize volatile loads with other side effects.
+    Root = getRoot();
+  else if (AA->pointsToConstantMemory(SV)) {
+    // Do not serialize (non-volatile) loads of constant memory with anything.
+    Root = DAG.getEntryNode();
+    ConstantMemory = true;
+  } else {
+    // Do not serialize non-volatile loads against each other.
+    Root = DAG.getRoot();
+  }
+
+  SmallVector<SDValue, 4> Values(NumValues);
+  SmallVector<SDValue, 4> Chains(NumValues);
+  EVT PtrVT = Ptr.getValueType();
+  for (unsigned i = 0; i != NumValues; ++i) {
+    SDValue A = DAG.getNode(ISD::ADD, getCurDebugLoc(),
+                            PtrVT, Ptr,
+                            DAG.getConstant(Offsets[i], PtrVT));
+    SDValue L = DAG.getLoad(ValueVTs[i], getCurDebugLoc(), Root,
+                            A, SV, Offsets[i], isVolatile, 
+                            isNonTemporal, Alignment);
+
+    Values[i] = L;
+    Chains[i] = L.getValue(1);
+  }
+
+  if (!ConstantMemory) {
+    SDValue Chain = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(),
+                                MVT::Other, &Chains[0], NumValues);
+    if (isVolatile)
+      DAG.setRoot(Chain);
+    else
+      PendingLoads.push_back(Chain);
+  }
+
+  setValue(&I, DAG.getNode(ISD::MERGE_VALUES, getCurDebugLoc(),
+                           DAG.getVTList(&ValueVTs[0], NumValues),
+                           &Values[0], NumValues));
+}
+
+void SelectionDAGBuilder::visitStore(const StoreInst &I) {
+  const Value *SrcV = I.getOperand(0);
+  const Value *PtrV = I.getOperand(1);
+
+  SmallVector<EVT, 4> ValueVTs;
+  SmallVector<uint64_t, 4> Offsets;
+  ComputeValueVTs(TLI, SrcV->getType(), ValueVTs, &Offsets);
+  unsigned NumValues = ValueVTs.size();
+  if (NumValues == 0)
+    return;
+
+  // Get the lowered operands. Note that we do this after
+  // checking if NumResults is zero, because with zero results
+  // the operands won't have values in the map.
+  SDValue Src = getValue(SrcV);
+  SDValue Ptr = getValue(PtrV);
+
+  SDValue Root = getRoot();
+  SmallVector<SDValue, 4> Chains(NumValues);
+  EVT PtrVT = Ptr.getValueType();
+  bool isVolatile = I.isVolatile();
+  bool isNonTemporal = I.getMetadata("nontemporal") != 0;
+  unsigned Alignment = I.getAlignment();
+
+  for (unsigned i = 0; i != NumValues; ++i) {
+    SDValue Add = DAG.getNode(ISD::ADD, getCurDebugLoc(), PtrVT, Ptr,
+                              DAG.getConstant(Offsets[i], PtrVT));
+    Chains[i] = DAG.getStore(Root, getCurDebugLoc(),
+                             SDValue(Src.getNode(), Src.getResNo() + i),
+                             Add, PtrV, Offsets[i], isVolatile, 
+                             isNonTemporal, Alignment);
+  }
+
+  DAG.setRoot(DAG.getNode(ISD::TokenFactor, getCurDebugLoc(),
+                          MVT::Other, &Chains[0], NumValues));
+}
+
+/// visitTargetIntrinsic - Lower a call of a target intrinsic to an INTRINSIC
+/// node.
+void SelectionDAGBuilder::visitTargetIntrinsic(const CallInst &I,
+                                               unsigned Intrinsic) {
+  bool HasChain = !I.doesNotAccessMemory();
+  bool OnlyLoad = HasChain && I.onlyReadsMemory();
+
+  // Build the operand list.
+  SmallVector<SDValue, 8> Ops;
+  if (HasChain) {  // If this intrinsic has side-effects, chainify it.
+    if (OnlyLoad) {
+      // We don't need to serialize loads against other loads.
+      Ops.push_back(DAG.getRoot());
+    } else {
+      Ops.push_back(getRoot());
+    }
+  }
+
+  // Info is set by getTgtMemInstrinsic
+  TargetLowering::IntrinsicInfo Info;
+  bool IsTgtIntrinsic = TLI.getTgtMemIntrinsic(Info, I, Intrinsic);
+
+  // Add the intrinsic ID as an integer operand if it's not a target intrinsic.
+  if (!IsTgtIntrinsic)
+    Ops.push_back(DAG.getConstant(Intrinsic, TLI.getPointerTy()));
+
+  // Add all operands of the call to the operand list.
+  for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i) {
+    SDValue Op = getValue(I.getOperand(i));
+    assert(TLI.isTypeLegal(Op.getValueType()) &&
+           "Intrinsic uses a non-legal type?");
+    Ops.push_back(Op);
+  }
+
+  SmallVector<EVT, 4> ValueVTs;
+  ComputeValueVTs(TLI, I.getType(), ValueVTs);
+#ifndef NDEBUG
+  for (unsigned Val = 0, E = ValueVTs.size(); Val != E; ++Val) {
+    assert(TLI.isTypeLegal(ValueVTs[Val]) &&
+           "Intrinsic uses a non-legal type?");
+  }
+#endif // NDEBUG
+
+  if (HasChain)
+    ValueVTs.push_back(MVT::Other);
+
+  SDVTList VTs = DAG.getVTList(ValueVTs.data(), ValueVTs.size());
+
+  // Create the node.
+  SDValue Result;
+  if (IsTgtIntrinsic) {
+    // This is target intrinsic that touches memory
+    Result = DAG.getMemIntrinsicNode(Info.opc, getCurDebugLoc(),
+                                     VTs, &Ops[0], Ops.size(),
+                                     Info.memVT, Info.ptrVal, Info.offset,
+                                     Info.align, Info.vol,
+                                     Info.readMem, Info.writeMem);
+  } else if (!HasChain) {
+    Result = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, getCurDebugLoc(),
+                         VTs, &Ops[0], Ops.size());
+  } else if (!I.getType()->isVoidTy()) {
+    Result = DAG.getNode(ISD::INTRINSIC_W_CHAIN, getCurDebugLoc(),
+                         VTs, &Ops[0], Ops.size());
+  } else {
+    Result = DAG.getNode(ISD::INTRINSIC_VOID, getCurDebugLoc(),
+                         VTs, &Ops[0], Ops.size());
+  }
+
+  if (HasChain) {
+    SDValue Chain = Result.getValue(Result.getNode()->getNumValues()-1);
+    if (OnlyLoad)
+      PendingLoads.push_back(Chain);
+    else
+      DAG.setRoot(Chain);
+  }
+
+  if (!I.getType()->isVoidTy()) {
+    if (const VectorType *PTy = dyn_cast<VectorType>(I.getType())) {
+      EVT VT = TLI.getValueType(PTy);
+      Result = DAG.getNode(ISD::BIT_CONVERT, getCurDebugLoc(), VT, Result);
+    }
+
+    setValue(&I, Result);
+  }
+}
+
+/// GetSignificand - Get the significand and build it into a floating-point
+/// number with exponent of 1:
+///
+///   Op = (Op & 0x007fffff) | 0x3f800000;
+///
+/// where Op is the hexidecimal representation of floating point value.
+static SDValue
+GetSignificand(SelectionDAG &DAG, SDValue Op, DebugLoc dl) {
+  SDValue t1 = DAG.getNode(ISD::AND, dl, MVT::i32, Op,
+                           DAG.getConstant(0x007fffff, MVT::i32));
+  SDValue t2 = DAG.getNode(ISD::OR, dl, MVT::i32, t1,
+                           DAG.getConstant(0x3f800000, MVT::i32));
+  return DAG.getNode(ISD::BIT_CONVERT, dl, MVT::f32, t2);
+}
+
+/// GetExponent - Get the exponent:
+///
+///   (float)(int)(((Op & 0x7f800000) >> 23) - 127);
+///
+/// where Op is the hexidecimal representation of floating point value.
+static SDValue
+GetExponent(SelectionDAG &DAG, SDValue Op, const TargetLowering &TLI,
+            DebugLoc dl) {
+  SDValue t0 = DAG.getNode(ISD::AND, dl, MVT::i32, Op,
+                           DAG.getConstant(0x7f800000, MVT::i32));
+  SDValue t1 = DAG.getNode(ISD::SRL, dl, MVT::i32, t0,
+                           DAG.getConstant(23, TLI.getPointerTy()));
+  SDValue t2 = DAG.getNode(ISD::SUB, dl, MVT::i32, t1,
+                           DAG.getConstant(127, MVT::i32));
+  return DAG.getNode(ISD::SINT_TO_FP, dl, MVT::f32, t2);
+}
+
+/// getF32Constant - Get 32-bit floating point constant.
+static SDValue
+getF32Constant(SelectionDAG &DAG, unsigned Flt) {
+  return DAG.getConstantFP(APFloat(APInt(32, Flt)), MVT::f32);
+}
+
+/// Inlined utility function to implement binary input atomic intrinsics for
+/// visitIntrinsicCall: I is a call instruction
+///                     Op is the associated NodeType for I
+const char *
+SelectionDAGBuilder::implVisitBinaryAtomic(const CallInst& I,
+                                           ISD::NodeType Op) {
+  SDValue Root = getRoot();
+  SDValue L =
+    DAG.getAtomic(Op, getCurDebugLoc(),
+                  getValue(I.getOperand(2)).getValueType().getSimpleVT(),
+                  Root,
+                  getValue(I.getOperand(1)),
+                  getValue(I.getOperand(2)),
+                  I.getOperand(1));
+  setValue(&I, L);
+  DAG.setRoot(L.getValue(1));
+  return 0;
+}
+
+// implVisitAluOverflow - Lower arithmetic overflow instrinsics.
+const char *
+SelectionDAGBuilder::implVisitAluOverflow(const CallInst &I, ISD::NodeType Op) {
+  SDValue Op1 = getValue(I.getOperand(1));
+  SDValue Op2 = getValue(I.getOperand(2));
+
+  SDVTList VTs = DAG.getVTList(Op1.getValueType(), MVT::i1);
+  setValue(&I, DAG.getNode(Op, getCurDebugLoc(), VTs, Op1, Op2));
+  return 0;
+}
+
+/// visitExp - Lower an exp intrinsic. Handles the special sequences for
+/// limited-precision mode.
+void
+SelectionDAGBuilder::visitExp(const CallInst &I) {
+  SDValue result;
+  DebugLoc dl = getCurDebugLoc();
+
+  if (getValue(I.getOperand(1)).getValueType() == MVT::f32 &&
+      LimitFloatPrecision > 0 && LimitFloatPrecision <= 18) {
     SDValue Op = getValue(I.getOperand(1));
 
     // Put the exponent in the right bit position for later addition to the
@@ -4320,642 +4480,432 @@
   case Intrinsic::atomic_load_umax:
     return implVisitBinaryAtomic(I, ISD::ATOMIC_LOAD_UMAX);
   case Intrinsic::atomic_swap:
-    return implVisitBinaryAtomic(I, ISD::ATOMIC_SWAP);
-
-  case Intrinsic::invariant_start:
-  case Intrinsic::lifetime_start:
-    // Discard region information.
-    setValue(&I, DAG.getUNDEF(TLI.getPointerTy()));
-    return 0;
-  case Intrinsic::invariant_end:
-  case Intrinsic::lifetime_end:
-    // Discard region information.
-    return 0;
-  }
-}
-
-void SelectionDAGBuilder::LowerCallTo(ImmutableCallSite CS, SDValue Callee,
-                                      bool isTailCall,
-                                      MachineBasicBlock *LandingPad) {
-  const PointerType *PT = cast<PointerType>(CS.getCalledValue()->getType());
-  const FunctionType *FTy = cast<FunctionType>(PT->getElementType());
-  const Type *RetTy = FTy->getReturnType();
-  MachineModuleInfo &MMI = DAG.getMachineFunction().getMMI();
-  MCSymbol *BeginLabel = 0;
-
-  TargetLowering::ArgListTy Args;
-  TargetLowering::ArgListEntry Entry;
-  Args.reserve(CS.arg_size());
-
-  // Check whether the function can return without sret-demotion.
-  SmallVector<EVT, 4> OutVTs;
-  SmallVector<ISD::ArgFlagsTy, 4> OutsFlags;
-  SmallVector<uint64_t, 4> Offsets;
-  getReturnInfo(RetTy, CS.getAttributes().getRetAttributes(),
-                OutVTs, OutsFlags, TLI, &Offsets);
-
-  bool CanLowerReturn = TLI.CanLowerReturn(CS.getCallingConv(),
-                        FTy->isVarArg(), OutVTs, OutsFlags, DAG);
-
-  SDValue DemoteStackSlot;
-
-  if (!CanLowerReturn) {
-    uint64_t TySize = TLI.getTargetData()->getTypeAllocSize(
-                      FTy->getReturnType());
-    unsigned Align  = TLI.getTargetData()->getPrefTypeAlignment(
-                      FTy->getReturnType());
-    MachineFunction &MF = DAG.getMachineFunction();
-    int SSFI = MF.getFrameInfo()->CreateStackObject(TySize, Align, false);
-    const Type *StackSlotPtrType = PointerType::getUnqual(FTy->getReturnType());
-
-    DemoteStackSlot = DAG.getFrameIndex(SSFI, TLI.getPointerTy());
-    Entry.Node = DemoteStackSlot;
-    Entry.Ty = StackSlotPtrType;
-    Entry.isSExt = false;
-    Entry.isZExt = false;
-    Entry.isInReg = false;
-    Entry.isSRet = true;
-    Entry.isNest = false;
-    Entry.isByVal = false;
-    Entry.Alignment = Align;
-    Args.push_back(Entry);
-    RetTy = Type::getVoidTy(FTy->getContext());
-  }
-
-  for (ImmutableCallSite::arg_iterator i = CS.arg_begin(), e = CS.arg_end();
-       i != e; ++i) {
-    SDValue ArgNode = getValue(*i);
-    Entry.Node = ArgNode; Entry.Ty = (*i)->getType();
-
-    unsigned attrInd = i - CS.arg_begin() + 1;
-    Entry.isSExt  = CS.paramHasAttr(attrInd, Attribute::SExt);
-    Entry.isZExt  = CS.paramHasAttr(attrInd, Attribute::ZExt);
-    Entry.isInReg = CS.paramHasAttr(attrInd, Attribute::InReg);
-    Entry.isSRet  = CS.paramHasAttr(attrInd, Attribute::StructRet);
-    Entry.isNest  = CS.paramHasAttr(attrInd, Attribute::Nest);
-    Entry.isByVal = CS.paramHasAttr(attrInd, Attribute::ByVal);
-    Entry.Alignment = CS.getParamAlignment(attrInd);
-    Args.push_back(Entry);
-  }
-
-  if (LandingPad) {
-    // Insert a label before the invoke call to mark the try range.  This can be
-    // used to detect deletion of the invoke via the MachineModuleInfo.
-    BeginLabel = MMI.getContext().CreateTempSymbol();
-
-    // For SjLj, keep track of which landing pads go with which invokes
-    // so as to maintain the ordering of pads in the LSDA.
-    unsigned CallSiteIndex = MMI.getCurrentCallSite();
-    if (CallSiteIndex) {
-      MMI.setCallSiteBeginLabel(BeginLabel, CallSiteIndex);
-      // Now that the call site is handled, stop tracking it.
-      MMI.setCurrentCallSite(0);
-    }
-
-    // Both PendingLoads and PendingExports must be flushed here;
-    // this call might not return.
-    (void)getRoot();
-    DAG.setRoot(DAG.getEHLabel(getCurDebugLoc(), getControlRoot(), BeginLabel));
-  }
-
-  // Check if target-independent constraints permit a tail call here.
-  // Target-dependent constraints are checked within TLI.LowerCallTo.
-  if (isTailCall &&
-      !isInTailCallPosition(CS, CS.getAttributes().getRetAttributes(), TLI))
-    isTailCall = false;
-
-  std::pair<SDValue,SDValue> Result =
-    TLI.LowerCallTo(getRoot(), RetTy,
-                    CS.paramHasAttr(0, Attribute::SExt),
-                    CS.paramHasAttr(0, Attribute::ZExt), FTy->isVarArg(),
-                    CS.paramHasAttr(0, Attribute::InReg), FTy->getNumParams(),
-                    CS.getCallingConv(),
-                    isTailCall,
-                    !CS.getInstruction()->use_empty(),
-                    Callee, Args, DAG, getCurDebugLoc());
-  assert((isTailCall || Result.second.getNode()) &&
-         "Non-null chain expected with non-tail call!");
-  assert((Result.second.getNode() || !Result.first.getNode()) &&
-         "Null value expected with tail call!");
-  if (Result.first.getNode()) {
-    setValue(CS.getInstruction(), Result.first);
-  } else if (!CanLowerReturn && Result.second.getNode()) {
-    // The instruction result is the result of loading from the
-    // hidden sret parameter.
-    SmallVector<EVT, 1> PVTs;
-    const Type *PtrRetTy = PointerType::getUnqual(FTy->getReturnType());
-
-    ComputeValueVTs(TLI, PtrRetTy, PVTs);
-    assert(PVTs.size() == 1 && "Pointers should fit in one register");
-    EVT PtrVT = PVTs[0];
-    unsigned NumValues = OutVTs.size();
-    SmallVector<SDValue, 4> Values(NumValues);
-    SmallVector<SDValue, 4> Chains(NumValues);
-
-    for (unsigned i = 0; i < NumValues; ++i) {
-      SDValue Add = DAG.getNode(ISD::ADD, getCurDebugLoc(), PtrVT,
-                                DemoteStackSlot,
-                                DAG.getConstant(Offsets[i], PtrVT));
-      SDValue L = DAG.getLoad(OutVTs[i], getCurDebugLoc(), Result.second,
-                              Add, NULL, Offsets[i], false, false, 1);
-      Values[i] = L;
-      Chains[i] = L.getValue(1);
-    }
-
-    SDValue Chain = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(),
-                                MVT::Other, &Chains[0], NumValues);
-    PendingLoads.push_back(Chain);
-    
-    // Collect the legal value parts into potentially illegal values
-    // that correspond to the original function's return values.
-    SmallVector<EVT, 4> RetTys;
-    RetTy = FTy->getReturnType();
-    ComputeValueVTs(TLI, RetTy, RetTys);
-    ISD::NodeType AssertOp = ISD::DELETED_NODE;
-    SmallVector<SDValue, 4> ReturnValues;
-    unsigned CurReg = 0;
-    for (unsigned I = 0, E = RetTys.size(); I != E; ++I) {
-      EVT VT = RetTys[I];
-      EVT RegisterVT = TLI.getRegisterType(RetTy->getContext(), VT);
-      unsigned NumRegs = TLI.getNumRegisters(RetTy->getContext(), VT);
-  
-      SDValue ReturnValue =
-        getCopyFromParts(DAG, getCurDebugLoc(), &Values[CurReg], NumRegs,
-                         RegisterVT, VT, AssertOp);
-      ReturnValues.push_back(ReturnValue);
-      CurReg += NumRegs;
-    }
-
-    setValue(CS.getInstruction(),
-             DAG.getNode(ISD::MERGE_VALUES, getCurDebugLoc(),
-                         DAG.getVTList(&RetTys[0], RetTys.size()),
-                         &ReturnValues[0], ReturnValues.size()));
-
-  }
-
-  // As a special case, a null chain means that a tail call has been emitted and
-  // the DAG root is already updated.
-  if (Result.second.getNode())
-    DAG.setRoot(Result.second);
-  else
-    HasTailCall = true;
-
-  if (LandingPad) {
-    // Insert a label at the end of the invoke call to mark the try range.  This
-    // can be used to detect deletion of the invoke via the MachineModuleInfo.
-    MCSymbol *EndLabel = MMI.getContext().CreateTempSymbol();
-    DAG.setRoot(DAG.getEHLabel(getCurDebugLoc(), getRoot(), EndLabel));
-
-    // Inform MachineModuleInfo of range.
-    MMI.addInvoke(LandingPad, BeginLabel, EndLabel);
-  }
-}
-
-/// IsOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
-/// value is equal or not-equal to zero.
-static bool IsOnlyUsedInZeroEqualityComparison(const Value *V) {
-  for (Value::const_use_iterator UI = V->use_begin(), E = V->use_end();
-       UI != E; ++UI) {
-    if (const ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
-      if (IC->isEquality())
-        if (const Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
-          if (C->isNullValue())
-            continue;
-    // Unknown instruction.
-    return false;
-  }
-  return true;
-}
-
-static SDValue getMemCmpLoad(const Value *PtrVal, MVT LoadVT,
-                             const Type *LoadTy,
-                             SelectionDAGBuilder &Builder) {
-
-  // Check to see if this load can be trivially constant folded, e.g. if the
-  // input is from a string literal.
-  if (const Constant *LoadInput = dyn_cast<Constant>(PtrVal)) {
-    // Cast pointer to the type we really want to load.
-    LoadInput = ConstantExpr::getBitCast(const_cast<Constant *>(LoadInput),
-                                         PointerType::getUnqual(LoadTy));
-
-    if (const Constant *LoadCst =
-          ConstantFoldLoadFromConstPtr(const_cast<Constant *>(LoadInput),
-                                       Builder.TD))
-      return Builder.getValue(LoadCst);
-  }
-
-  // Otherwise, we have to emit the load.  If the pointer is to unfoldable but
-  // still constant memory, the input chain can be the entry node.
-  SDValue Root;
-  bool ConstantMemory = false;
+    return implVisitBinaryAtomic(I, ISD::ATOMIC_SWAP);
 
-  // Do not serialize (non-volatile) loads of constant memory with anything.
-  if (Builder.AA->pointsToConstantMemory(PtrVal)) {
-    Root = Builder.DAG.getEntryNode();
-    ConstantMemory = true;
-  } else {
-    // Do not serialize non-volatile loads against each other.
-    Root = Builder.DAG.getRoot();
+  case Intrinsic::invariant_start:
+  case Intrinsic::lifetime_start:
+    // Discard region information.
+    setValue(&I, DAG.getUNDEF(TLI.getPointerTy()));
+    return 0;
+  case Intrinsic::invariant_end:
+  case Intrinsic::lifetime_end:
+    // Discard region information.
+    return 0;
   }
-
-  SDValue Ptr = Builder.getValue(PtrVal);
-  SDValue LoadVal = Builder.DAG.getLoad(LoadVT, Builder.getCurDebugLoc(), Root,
-                                        Ptr, PtrVal /*SrcValue*/, 0/*SVOffset*/,
-                                        false /*volatile*/,
-                                        false /*nontemporal*/, 1 /* align=1 */);
-
-  if (!ConstantMemory)
-    Builder.PendingLoads.push_back(LoadVal.getValue(1));
-  return LoadVal;
 }
 
+void SelectionDAGBuilder::LowerCallTo(ImmutableCallSite CS, SDValue Callee,
+                                      bool isTailCall,
+                                      MachineBasicBlock *LandingPad) {
+  const PointerType *PT = cast<PointerType>(CS.getCalledValue()->getType());
+  const FunctionType *FTy = cast<FunctionType>(PT->getElementType());
+  const Type *RetTy = FTy->getReturnType();
+  MachineModuleInfo &MMI = DAG.getMachineFunction().getMMI();
+  MCSymbol *BeginLabel = 0;
 
-/// visitMemCmpCall - See if we can lower a call to memcmp in an optimized form.
-/// If so, return true and lower it, otherwise return false and it will be
-/// lowered like a normal call.
-bool SelectionDAGBuilder::visitMemCmpCall(const CallInst &I) {
-  // Verify that the prototype makes sense.  int memcmp(void*,void*,size_t)
-  if (I.getNumOperands() != 4)
-    return false;
+  TargetLowering::ArgListTy Args;
+  TargetLowering::ArgListEntry Entry;
+  Args.reserve(CS.arg_size());
 
-  const Value *LHS = I.getOperand(1), *RHS = I.getOperand(2);
-  if (!LHS->getType()->isPointerTy() || !RHS->getType()->isPointerTy() ||
-      !I.getOperand(3)->getType()->isIntegerTy() ||
-      !I.getType()->isIntegerTy())
-    return false;
+  // Check whether the function can return without sret-demotion.
+  SmallVector<EVT, 4> OutVTs;
+  SmallVector<ISD::ArgFlagsTy, 4> OutsFlags;
+  SmallVector<uint64_t, 4> Offsets;
+  getReturnInfo(RetTy, CS.getAttributes().getRetAttributes(),
+                OutVTs, OutsFlags, TLI, &Offsets);
 
-  const ConstantInt *Size = dyn_cast<ConstantInt>(I.getOperand(3));
+  bool CanLowerReturn = TLI.CanLowerReturn(CS.getCallingConv(),
+                        FTy->isVarArg(), OutVTs, OutsFlags, DAG);
 
-  // memcmp(S1,S2,2) != 0 -> (*(short*)LHS != *(short*)RHS)  != 0
-  // memcmp(S1,S2,4) != 0 -> (*(int*)LHS != *(int*)RHS)  != 0
-  if (Size && IsOnlyUsedInZeroEqualityComparison(&I)) {
-    bool ActuallyDoIt = true;
-    MVT LoadVT;
-    const Type *LoadTy;
-    switch (Size->getZExtValue()) {
-    default:
-      LoadVT = MVT::Other;
-      LoadTy = 0;
-      ActuallyDoIt = false;
-      break;
-    case 2:
-      LoadVT = MVT::i16;
-      LoadTy = Type::getInt16Ty(Size->getContext());
-      break;
-    case 4:
-      LoadVT = MVT::i32;
-      LoadTy = Type::getInt32Ty(Size->getContext());
-      break;
-    case 8:
-      LoadVT = MVT::i64;
-      LoadTy = Type::getInt64Ty(Size->getContext());
-      break;
-        /*
-    case 16:
-      LoadVT = MVT::v4i32;
-      LoadTy = Type::getInt32Ty(Size->getContext());
-      LoadTy = VectorType::get(LoadTy, 4);
-      break;
-         */
-    }
+  SDValue DemoteStackSlot;
 
-    // This turns into unaligned loads.  We only do this if the target natively
-    // supports the MVT we'll be loading or if it is small enough (<= 4) that
-    // we'll only produce a small number of byte loads.
+  if (!CanLowerReturn) {
+    uint64_t TySize = TLI.getTargetData()->getTypeAllocSize(
+                      FTy->getReturnType());
+    unsigned Align  = TLI.getTargetData()->getPrefTypeAlignment(
+                      FTy->getReturnType());
+    MachineFunction &MF = DAG.getMachineFunction();
+    int SSFI = MF.getFrameInfo()->CreateStackObject(TySize, Align, false);
+    const Type *StackSlotPtrType = PointerType::getUnqual(FTy->getReturnType());
 
-    // Require that we can find a legal MVT, and only do this if the target
-    // supports unaligned loads of that type.  Expanding into byte loads would
-    // bloat the code.
-    if (ActuallyDoIt && Size->getZExtValue() > 4) {
-      // TODO: Handle 5 byte compare as 4-byte + 1 byte.
-      // TODO: Handle 8 byte compare on x86-32 as two 32-bit loads.
-      if (!TLI.isTypeLegal(LoadVT) ||!TLI.allowsUnalignedMemoryAccesses(LoadVT))
-        ActuallyDoIt = false;
-    }
+    DemoteStackSlot = DAG.getFrameIndex(SSFI, TLI.getPointerTy());
+    Entry.Node = DemoteStackSlot;
+    Entry.Ty = StackSlotPtrType;
+    Entry.isSExt = false;
+    Entry.isZExt = false;
+    Entry.isInReg = false;
+    Entry.isSRet = true;
+    Entry.isNest = false;
+    Entry.isByVal = false;
+    Entry.Alignment = Align;
+    Args.push_back(Entry);
+    RetTy = Type::getVoidTy(FTy->getContext());
+  }
 
-    if (ActuallyDoIt) {
-      SDValue LHSVal = getMemCmpLoad(LHS, LoadVT, LoadTy, *this);
-      SDValue RHSVal = getMemCmpLoad(RHS, LoadVT, LoadTy, *this);
+  for (ImmutableCallSite::arg_iterator i = CS.arg_begin(), e = CS.arg_end();
+       i != e; ++i) {
+    SDValue ArgNode = getValue(*i);
+    Entry.Node = ArgNode; Entry.Ty = (*i)->getType();
 
-      SDValue Res = DAG.getSetCC(getCurDebugLoc(), MVT::i1, LHSVal, RHSVal,
-                                 ISD::SETNE);
-      EVT CallVT = TLI.getValueType(I.getType(), true);
-      setValue(&I, DAG.getZExtOrTrunc(Res, getCurDebugLoc(), CallVT));
-      return true;
-    }
+    unsigned attrInd = i - CS.arg_begin() + 1;
+    Entry.isSExt  = CS.paramHasAttr(attrInd, Attribute::SExt);
+    Entry.isZExt  = CS.paramHasAttr(attrInd, Attribute::ZExt);
+    Entry.isInReg = CS.paramHasAttr(attrInd, Attribute::InReg);
+    Entry.isSRet  = CS.paramHasAttr(attrInd, Attribute::StructRet);
+    Entry.isNest  = CS.paramHasAttr(attrInd, Attribute::Nest);
+    Entry.isByVal = CS.paramHasAttr(attrInd, Attribute::ByVal);
+    Entry.Alignment = CS.getParamAlignment(attrInd);
+    Args.push_back(Entry);
   }
 
+  if (LandingPad) {
+    // Insert a label before the invoke call to mark the try range.  This can be
+    // used to detect deletion of the invoke via the MachineModuleInfo.
+    BeginLabel = MMI.getContext().CreateTempSymbol();
 
-  return false;
-}
+    // For SjLj, keep track of which landing pads go with which invokes
+    // so as to maintain the ordering of pads in the LSDA.
+    unsigned CallSiteIndex = MMI.getCurrentCallSite();
+    if (CallSiteIndex) {
+      MMI.setCallSiteBeginLabel(BeginLabel, CallSiteIndex);
+      // Now that the call site is handled, stop tracking it.
+      MMI.setCurrentCallSite(0);
+    }
 
+    // Both PendingLoads and PendingExports must be flushed here;
+    // this call might not return.
+    (void)getRoot();
+    DAG.setRoot(DAG.getEHLabel(getCurDebugLoc(), getControlRoot(), BeginLabel));
+  }
 
-void SelectionDAGBuilder::visitCall(const CallInst &I) {
-  const char *RenameFn = 0;
-  if (Function *F = I.getCalledFunction()) {
-    if (F->isDeclaration()) {
-      const TargetIntrinsicInfo *II = TM.getIntrinsicInfo();
-      if (II) {
-        if (unsigned IID = II->getIntrinsicID(F)) {
-          RenameFn = visitIntrinsicCall(I, IID);
-          if (!RenameFn)
-            return;
-        }
-      }
-      if (unsigned IID = F->getIntrinsicID()) {
-        RenameFn = visitIntrinsicCall(I, IID);
-        if (!RenameFn)
-          return;
-      }
-    }
+  // Check if target-independent constraints permit a tail call here.
+  // Target-dependent constraints are checked within TLI.LowerCallTo.
+  if (isTailCall &&
+      !isInTailCallPosition(CS, CS.getAttributes().getRetAttributes(), TLI))
+    isTailCall = false;
 
-    // Check for well-known libc/libm calls.  If the function is internal, it
-    // can't be a library call.
-    if (!F->hasLocalLinkage() && F->hasName()) {
-      StringRef Name = F->getName();
-      if (Name == "copysign" || Name == "copysignf" || Name == "copysignl") {
-        if (I.getNumOperands() == 3 &&   // Basic sanity checks.
-            I.getOperand(1)->getType()->isFloatingPointTy() &&
-            I.getType() == I.getOperand(1)->getType() &&
-            I.getType() == I.getOperand(2)->getType()) {
-          SDValue LHS = getValue(I.getOperand(1));
-          SDValue RHS = getValue(I.getOperand(2));
-          setValue(&I, DAG.getNode(ISD::FCOPYSIGN, getCurDebugLoc(),
-                                   LHS.getValueType(), LHS, RHS));
-          return;
-        }
-      } else if (Name == "fabs" || Name == "fabsf" || Name == "fabsl") {
-        if (I.getNumOperands() == 2 &&   // Basic sanity checks.
-            I.getOperand(1)->getType()->isFloatingPointTy() &&
-            I.getType() == I.getOperand(1)->getType()) {
-          SDValue Tmp = getValue(I.getOperand(1));
-          setValue(&I, DAG.getNode(ISD::FABS, getCurDebugLoc(),
-                                   Tmp.getValueType(), Tmp));
-          return;
-        }
-      } else if (Name == "sin" || Name == "sinf" || Name == "sinl") {
-        if (I.getNumOperands() == 2 &&   // Basic sanity checks.
-            I.getOperand(1)->getType()->isFloatingPointTy() &&
-            I.getType() == I.getOperand(1)->getType() &&
-            I.onlyReadsMemory()) {
-          SDValue Tmp = getValue(I.getOperand(1));
-          setValue(&I, DAG.getNode(ISD::FSIN, getCurDebugLoc(),
-                                   Tmp.getValueType(), Tmp));
-          return;
-        }
-      } else if (Name == "cos" || Name == "cosf" || Name == "cosl") {
-        if (I.getNumOperands() == 2 &&   // Basic sanity checks.
-            I.getOperand(1)->getType()->isFloatingPointTy() &&
-            I.getType() == I.getOperand(1)->getType() &&
-            I.onlyReadsMemory()) {
-          SDValue Tmp = getValue(I.getOperand(1));
-          setValue(&I, DAG.getNode(ISD::FCOS, getCurDebugLoc(),
-                                   Tmp.getValueType(), Tmp));
-          return;
-        }
-      } else if (Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl") {
-        if (I.getNumOperands() == 2 &&   // Basic sanity checks.
-            I.getOperand(1)->getType()->isFloatingPointTy() &&
-            I.getType() == I.getOperand(1)->getType() &&
-            I.onlyReadsMemory()) {
-          SDValue Tmp = getValue(I.getOperand(1));
-          setValue(&I, DAG.getNode(ISD::FSQRT, getCurDebugLoc(),
-                                   Tmp.getValueType(), Tmp));
-          return;
-        }
-      } else if (Name == "memcmp") {
-        if (visitMemCmpCall(I))
-          return;
-      }
+  std::pair<SDValue,SDValue> Result =
+    TLI.LowerCallTo(getRoot(), RetTy,
+                    CS.paramHasAttr(0, Attribute::SExt),
+                    CS.paramHasAttr(0, Attribute::ZExt), FTy->isVarArg(),
+                    CS.paramHasAttr(0, Attribute::InReg), FTy->getNumParams(),
+                    CS.getCallingConv(),
+                    isTailCall,
+                    !CS.getInstruction()->use_empty(),
+                    Callee, Args, DAG, getCurDebugLoc());
+  assert((isTailCall || Result.second.getNode()) &&
+         "Non-null chain expected with non-tail call!");
+  assert((Result.second.getNode() || !Result.first.getNode()) &&
+         "Null value expected with tail call!");
+  if (Result.first.getNode()) {
+    setValue(CS.getInstruction(), Result.first);
+  } else if (!CanLowerReturn && Result.second.getNode()) {
+    // The instruction result is the result of loading from the
+    // hidden sret parameter.
+    SmallVector<EVT, 1> PVTs;
+    const Type *PtrRetTy = PointerType::getUnqual(FTy->getReturnType());
+
+    ComputeValueVTs(TLI, PtrRetTy, PVTs);
+    assert(PVTs.size() == 1 && "Pointers should fit in one register");
+    EVT PtrVT = PVTs[0];
+    unsigned NumValues = OutVTs.size();
+    SmallVector<SDValue, 4> Values(NumValues);
+    SmallVector<SDValue, 4> Chains(NumValues);
+
+    for (unsigned i = 0; i < NumValues; ++i) {
+      SDValue Add = DAG.getNode(ISD::ADD, getCurDebugLoc(), PtrVT,
+                                DemoteStackSlot,
+                                DAG.getConstant(Offsets[i], PtrVT));
+      SDValue L = DAG.getLoad(OutVTs[i], getCurDebugLoc(), Result.second,
+                              Add, NULL, Offsets[i], false, false, 1);
+      Values[i] = L;
+      Chains[i] = L.getValue(1);
     }
-  } else if (isa<InlineAsm>(I.getOperand(0))) {
-    visitInlineAsm(&I);
-    return;
-  }
 
-  SDValue Callee;
-  if (!RenameFn)
-    Callee = getValue(I.getOperand(0));
-  else
-    Callee = DAG.getExternalSymbol(RenameFn, TLI.getPointerTy());
+    SDValue Chain = DAG.getNode(ISD::TokenFactor, getCurDebugLoc(),
+                                MVT::Other, &Chains[0], NumValues);
+    PendingLoads.push_back(Chain);
+    
+    // Collect the legal value parts into potentially illegal values
+    // that correspond to the original function's return values.
+    SmallVector<EVT, 4> RetTys;
+    RetTy = FTy->getReturnType();
+    ComputeValueVTs(TLI, RetTy, RetTys);
+    ISD::NodeType AssertOp = ISD::DELETED_NODE;
+    SmallVector<SDValue, 4> ReturnValues;
+    unsigned CurReg = 0;
+    for (unsigned I = 0, E = RetTys.size(); I != E; ++I) {
+      EVT VT = RetTys[I];
+      EVT RegisterVT = TLI.getRegisterType(RetTy->getContext(), VT);
+      unsigned NumRegs = TLI.getNumRegisters(RetTy->getContext(), VT);
+  
+      SDValue ReturnValue =
+        getCopyFromParts(DAG, getCurDebugLoc(), &Values[CurReg], NumRegs,
+                         RegisterVT, VT, AssertOp);
+      ReturnValues.push_back(ReturnValue);
+      CurReg += NumRegs;
+    }
 
-  // Check if we can potentially perform a tail call. More detailed checking is
-  // be done within LowerCallTo, after more information about the call is known.
-  LowerCallTo(&I, Callee, I.isTailCall());
-}
+    setValue(CS.getInstruction(),
+             DAG.getNode(ISD::MERGE_VALUES, getCurDebugLoc(),
+                         DAG.getVTList(&RetTys[0], RetTys.size()),
+                         &ReturnValues[0], ReturnValues.size()));
 
-/// getCopyFromRegs - Emit a series of CopyFromReg nodes that copies from
-/// this value and returns the result as a ValueVT value.  This uses
-/// Chain/Flag as the input and updates them for the output Chain/Flag.
-/// If the Flag pointer is NULL, no flag is used.
-SDValue RegsForValue::getCopyFromRegs(SelectionDAG &DAG,
-                                      FunctionLoweringInfo &FuncInfo,
-                                      DebugLoc dl,
-                                      SDValue &Chain, SDValue *Flag) const {
-  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+  }
 
-  // Assemble the legal parts into the final values.
-  SmallVector<SDValue, 4> Values(ValueVTs.size());
-  SmallVector<SDValue, 8> Parts;
-  for (unsigned Value = 0, Part = 0, e = ValueVTs.size(); Value != e; ++Value) {
-    // Copy the legal parts from the registers.
-    EVT ValueVT = ValueVTs[Value];
-    unsigned NumRegs = TLI.getNumRegisters(*DAG.getContext(), ValueVT);
-    EVT RegisterVT = RegVTs[Value];
+  // As a special case, a null chain means that a tail call has been emitted and
+  // the DAG root is already updated.
+  if (Result.second.getNode())
+    DAG.setRoot(Result.second);
+  else
+    HasTailCall = true;
 
-    Parts.resize(NumRegs);
-    for (unsigned i = 0; i != NumRegs; ++i) {
-      SDValue P;
-      if (Flag == 0) {
-        P = DAG.getCopyFromReg(Chain, dl, Regs[Part+i], RegisterVT);
-      } else {
-        P = DAG.getCopyFromReg(Chain, dl, Regs[Part+i], RegisterVT, *Flag);
-        *Flag = P.getValue(2);
-      }
+  if (LandingPad) {
+    // Insert a label at the end of the invoke call to mark the try range.  This
+    // can be used to detect deletion of the invoke via the MachineModuleInfo.
+    MCSymbol *EndLabel = MMI.getContext().CreateTempSymbol();
+    DAG.setRoot(DAG.getEHLabel(getCurDebugLoc(), getRoot(), EndLabel));
 
-      Chain = P.getValue(1);
+    // Inform MachineModuleInfo of range.
+    MMI.addInvoke(LandingPad, BeginLabel, EndLabel);
+  }
+}
 
-      // If the source register was virtual and if we know something about it,
-      // add an assert node.
-      if (TargetRegisterInfo::isVirtualRegister(Regs[Part+i]) &&
-          RegisterVT.isInteger() && !RegisterVT.isVector()) {
-        unsigned SlotNo = Regs[Part+i]-TargetRegisterInfo::FirstVirtualRegister;
-        if (FuncInfo.LiveOutRegInfo.size() > SlotNo) {
-          const FunctionLoweringInfo::LiveOutInfo &LOI =
-            FuncInfo.LiveOutRegInfo[SlotNo];
+/// IsOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
+/// value is equal or not-equal to zero.
+static bool IsOnlyUsedInZeroEqualityComparison(const Value *V) {
+  for (Value::const_use_iterator UI = V->use_begin(), E = V->use_end();
+       UI != E; ++UI) {
+    if (const ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
+      if (IC->isEquality())
+        if (const Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
+          if (C->isNullValue())
+            continue;
+    // Unknown instruction.
+    return false;
+  }
+  return true;
+}
 
-          unsigned RegSize = RegisterVT.getSizeInBits();
-          unsigned NumSignBits = LOI.NumSignBits;
-          unsigned NumZeroBits = LOI.KnownZero.countLeadingOnes();
+static SDValue getMemCmpLoad(const Value *PtrVal, MVT LoadVT,
+                             const Type *LoadTy,
+                             SelectionDAGBuilder &Builder) {
 
-          // FIXME: We capture more information than the dag can represent.  For
-          // now, just use the tightest assertzext/assertsext possible.
-          bool isSExt = true;
-          EVT FromVT(MVT::Other);
-          if (NumSignBits == RegSize)
-            isSExt = true, FromVT = MVT::i1;   // ASSERT SEXT 1
-          else if (NumZeroBits >= RegSize-1)
-            isSExt = false, FromVT = MVT::i1;  // ASSERT ZEXT 1
-          else if (NumSignBits > RegSize-8)
-            isSExt = true, FromVT = MVT::i8;   // ASSERT SEXT 8
-          else if (NumZeroBits >= RegSize-8)
-            isSExt = false, FromVT = MVT::i8;  // ASSERT ZEXT 8
-          else if (NumSignBits > RegSize-16)
-            isSExt = true, FromVT = MVT::i16;  // ASSERT SEXT 16
-          else if (NumZeroBits >= RegSize-16)
-            isSExt = false, FromVT = MVT::i16; // ASSERT ZEXT 16
-          else if (NumSignBits > RegSize-32)
-            isSExt = true, FromVT = MVT::i32;  // ASSERT SEXT 32
-          else if (NumZeroBits >= RegSize-32)
-            isSExt = false, FromVT = MVT::i32; // ASSERT ZEXT 32
+  // Check to see if this load can be trivially constant folded, e.g. if the
+  // input is from a string literal.
+  if (const Constant *LoadInput = dyn_cast<Constant>(PtrVal)) {
+    // Cast pointer to the type we really want to load.
+    LoadInput = ConstantExpr::getBitCast(const_cast<Constant *>(LoadInput),
+                                         PointerType::getUnqual(LoadTy));
 
-          if (FromVT != MVT::Other)
-            P = DAG.getNode(isSExt ? ISD::AssertSext : ISD::AssertZext, dl,
-                            RegisterVT, P, DAG.getValueType(FromVT));
-        }
-      }
+    if (const Constant *LoadCst =
+          ConstantFoldLoadFromConstPtr(const_cast<Constant *>(LoadInput),
+                                       Builder.TD))
+      return Builder.getValue(LoadCst);
+  }
 
-      Parts[i] = P;
-    }
+  // Otherwise, we have to emit the load.  If the pointer is to unfoldable but
+  // still constant memory, the input chain can be the entry node.
+  SDValue Root;
+  bool ConstantMemory = false;
 
-    Values[Value] = getCopyFromParts(DAG, dl, Parts.begin(),
-                                     NumRegs, RegisterVT, ValueVT);
-    Part += NumRegs;
-    Parts.clear();
+  // Do not serialize (non-volatile) loads of constant memory with anything.
+  if (Builder.AA->pointsToConstantMemory(PtrVal)) {
+    Root = Builder.DAG.getEntryNode();
+    ConstantMemory = true;
+  } else {
+    // Do not serialize non-volatile loads against each other.
+    Root = Builder.DAG.getRoot();
   }
 
-  return DAG.getNode(ISD::MERGE_VALUES, dl,
-                     DAG.getVTList(&ValueVTs[0], ValueVTs.size()),
-                     &Values[0], ValueVTs.size());
+  SDValue Ptr = Builder.getValue(PtrVal);
+  SDValue LoadVal = Builder.DAG.getLoad(LoadVT, Builder.getCurDebugLoc(), Root,
+                                        Ptr, PtrVal /*SrcValue*/, 0/*SVOffset*/,
+                                        false /*volatile*/,
+                                        false /*nontemporal*/, 1 /* align=1 */);
+
+  if (!ConstantMemory)
+    Builder.PendingLoads.push_back(LoadVal.getValue(1));
+  return LoadVal;
 }
 
-/// getCopyToRegs - Emit a series of CopyToReg nodes that copies the
-/// specified value into the registers specified by this object.  This uses
-/// Chain/Flag as the input and updates them for the output Chain/Flag.
-/// If the Flag pointer is NULL, no flag is used.
-void RegsForValue::getCopyToRegs(SDValue Val, SelectionDAG &DAG, DebugLoc dl,
-                                 SDValue &Chain, SDValue *Flag) const {
-  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
 
-  // Get the list of the values's legal parts.
-  unsigned NumRegs = Regs.size();
-  SmallVector<SDValue, 8> Parts(NumRegs);
-  for (unsigned Value = 0, Part = 0, e = ValueVTs.size(); Value != e; ++Value) {
-    EVT ValueVT = ValueVTs[Value];
-    unsigned NumParts = TLI.getNumRegisters(*DAG.getContext(), ValueVT);
-    EVT RegisterVT = RegVTs[Value];
+/// visitMemCmpCall - See if we can lower a call to memcmp in an optimized form.
+/// If so, return true and lower it, otherwise return false and it will be
+/// lowered like a normal call.
+bool SelectionDAGBuilder::visitMemCmpCall(const CallInst &I) {
+  // Verify that the prototype makes sense.  int memcmp(void*,void*,size_t)
+  if (I.getNumOperands() != 4)
+    return false;
 
-    getCopyToParts(DAG, dl,
-                   Val.getValue(Val.getResNo() + Value),
-                   &Parts[Part], NumParts, RegisterVT);
-    Part += NumParts;
-  }
+  const Value *LHS = I.getOperand(1), *RHS = I.getOperand(2);
+  if (!LHS->getType()->isPointerTy() || !RHS->getType()->isPointerTy() ||
+      !I.getOperand(3)->getType()->isIntegerTy() ||
+      !I.getType()->isIntegerTy())
+    return false;
 
-  // Copy the parts into the registers.
-  SmallVector<SDValue, 8> Chains(NumRegs);
-  for (unsigned i = 0; i != NumRegs; ++i) {
-    SDValue Part;
-    if (Flag == 0) {
-      Part = DAG.getCopyToReg(Chain, dl, Regs[i], Parts[i]);
-    } else {
-      Part = DAG.getCopyToReg(Chain, dl, Regs[i], Parts[i], *Flag);
-      *Flag = Part.getValue(1);
+  const ConstantInt *Size = dyn_cast<ConstantInt>(I.getOperand(3));
+
+  // memcmp(S1,S2,2) != 0 -> (*(short*)LHS != *(short*)RHS)  != 0
+  // memcmp(S1,S2,4) != 0 -> (*(int*)LHS != *(int*)RHS)  != 0
+  if (Size && IsOnlyUsedInZeroEqualityComparison(&I)) {
+    bool ActuallyDoIt = true;
+    MVT LoadVT;
+    const Type *LoadTy;
+    switch (Size->getZExtValue()) {
+    default:
+      LoadVT = MVT::Other;
+      LoadTy = 0;
+      ActuallyDoIt = false;
+      break;
+    case 2:
+      LoadVT = MVT::i16;
+      LoadTy = Type::getInt16Ty(Size->getContext());
+      break;
+    case 4:
+      LoadVT = MVT::i32;
+      LoadTy = Type::getInt32Ty(Size->getContext());
+      break;
+    case 8:
+      LoadVT = MVT::i64;
+      LoadTy = Type::getInt64Ty(Size->getContext());
+      break;
+        /*
+    case 16:
+      LoadVT = MVT::v4i32;
+      LoadTy = Type::getInt32Ty(Size->getContext());
+      LoadTy = VectorType::get(LoadTy, 4);
+      break;
+         */
     }
 
-    Chains[i] = Part.getValue(0);
-  }
-
-  if (NumRegs == 1 || Flag)
-    // If NumRegs > 1 && Flag is used then the use of the last CopyToReg is
-    // flagged to it. That is the CopyToReg nodes and the user are considered
-    // a single scheduling unit. If we create a TokenFactor and return it as
-    // chain, then the TokenFactor is both a predecessor (operand) of the
-    // user as well as a successor (the TF operands are flagged to the user).
-    // c1, f1 = CopyToReg
-    // c2, f2 = CopyToReg
-    // c3     = TokenFactor c1, c2
-    // ...
-    //        = op c3, ..., f2
-    Chain = Chains[NumRegs-1];
-  else
-    Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &Chains[0], NumRegs);
-}
+    // This turns into unaligned loads.  We only do this if the target natively
+    // supports the MVT we'll be loading or if it is small enough (<= 4) that
+    // we'll only produce a small number of byte loads.
 
-/// AddInlineAsmOperands - Add this value to the specified inlineasm node
-/// operand list.  This adds the code marker and includes the number of
-/// values added into it.
-void RegsForValue::AddInlineAsmOperands(unsigned Code, bool HasMatching,
-                                        unsigned MatchingIdx,
-                                        SelectionDAG &DAG,
-                                        std::vector<SDValue> &Ops) const {
-  const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+    // Require that we can find a legal MVT, and only do this if the target
+    // supports unaligned loads of that type.  Expanding into byte loads would
+    // bloat the code.
+    if (ActuallyDoIt && Size->getZExtValue() > 4) {
+      // TODO: Handle 5 byte compare as 4-byte + 1 byte.
+      // TODO: Handle 8 byte compare on x86-32 as two 32-bit loads.
+      if (!TLI.isTypeLegal(LoadVT) ||!TLI.allowsUnalignedMemoryAccesses(LoadVT))
+        ActuallyDoIt = false;
+    }
 
-  unsigned Flag = InlineAsm::getFlagWord(Code, Regs.size());
-  if (HasMatching)
-    Flag = InlineAsm::getFlagWordForMatchingOp(Flag, MatchingIdx);
-  SDValue Res = DAG.getTargetConstant(Flag, MVT::i32);
-  Ops.push_back(Res);
+    if (ActuallyDoIt) {
+      SDValue LHSVal = getMemCmpLoad(LHS, LoadVT, LoadTy, *this);
+      SDValue RHSVal = getMemCmpLoad(RHS, LoadVT, LoadTy, *this);
 
-  for (unsigned Value = 0, Reg = 0, e = ValueVTs.size(); Value != e; ++Value) {
-    unsigned NumRegs = TLI.getNumRegisters(*DAG.getContext(), ValueVTs[Value]);
-    EVT RegisterVT = RegVTs[Value];
-    for (unsigned i = 0; i != NumRegs; ++i) {
-      assert(Reg < Regs.size() && "Mismatch in # registers expected");
-      Ops.push_back(DAG.getRegister(Regs[Reg++], RegisterVT));
+      SDValue Res = DAG.getSetCC(getCurDebugLoc(), MVT::i1, LHSVal, RHSVal,
+                                 ISD::SETNE);
+      EVT CallVT = TLI.getValueType(I.getType(), true);
+      setValue(&I, DAG.getZExtOrTrunc(Res, getCurDebugLoc(), CallVT));
+      return true;
     }
   }
+
+
+  return false;
 }
 
-/// isAllocatableRegister - If the specified register is safe to allocate,
-/// i.e. it isn't a stack pointer or some other special register, return the
-/// register class for the register.  Otherwise, return null.
-static const TargetRegisterClass *
-isAllocatableRegister(unsigned Reg, MachineFunction &MF,
-                      const TargetLowering &TLI,
-                      const TargetRegisterInfo *TRI) {
-  EVT FoundVT = MVT::Other;
-  const TargetRegisterClass *FoundRC = 0;
-  for (TargetRegisterInfo::regclass_iterator RCI = TRI->regclass_begin(),
-       E = TRI->regclass_end(); RCI != E; ++RCI) {
-    EVT ThisVT = MVT::Other;
 
-    const TargetRegisterClass *RC = *RCI;
-    // If none of the value types for this register class are valid, we
-    // can't use it.  For example, 64-bit reg classes on 32-bit targets.
-    for (TargetRegisterClass::vt_iterator I = RC->vt_begin(), E = RC->vt_end();
-         I != E; ++I) {
-      if (TLI.isTypeLegal(*I)) {
-        // If we have already found this register in a different register class,
-        // choose the one with the largest VT specified.  For example, on
-        // PowerPC, we favor f64 register classes over f32.
-        if (FoundVT == MVT::Other || FoundVT.bitsLT(*I)) {
-          ThisVT = *I;
-          break;
+void SelectionDAGBuilder::visitCall(const CallInst &I) {
+  const char *RenameFn = 0;
+  if (Function *F = I.getCalledFunction()) {
+    if (F->isDeclaration()) {
+      const TargetIntrinsicInfo *II = TM.getIntrinsicInfo();
+      if (II) {
+        if (unsigned IID = II->getIntrinsicID(F)) {
+          RenameFn = visitIntrinsicCall(I, IID);
+          if (!RenameFn)
+            return;
         }
       }
+      if (unsigned IID = F->getIntrinsicID()) {
+        RenameFn = visitIntrinsicCall(I, IID);
+        if (!RenameFn)
+          return;
+      }
     }
 
-    if (ThisVT == MVT::Other) continue;
-
-    // NOTE: This isn't ideal.  In particular, this might allocate the
-    // frame pointer in functions that need it (due to them not being taken
-    // out of allocation, because a variable sized allocation hasn't been seen
-    // yet).  This is a slight code pessimization, but should still work.
-    for (TargetRegisterClass::iterator I = RC->allocation_order_begin(MF),
-         E = RC->allocation_order_end(MF); I != E; ++I)
-      if (*I == Reg) {
-        // We found a matching register class.  Keep looking at others in case
-        // we find one with larger registers that this physreg is also in.
-        FoundRC = RC;
-        FoundVT = ThisVT;
-        break;
+    // Check for well-known libc/libm calls.  If the function is internal, it
+    // can't be a library call.
+    if (!F->hasLocalLinkage() && F->hasName()) {
+      StringRef Name = F->getName();
+      if (Name == "copysign" || Name == "copysignf" || Name == "copysignl") {
+        if (I.getNumOperands() == 3 &&   // Basic sanity checks.
+            I.getOperand(1)->getType()->isFloatingPointTy() &&
+            I.getType() == I.getOperand(1)->getType() &&
+            I.getType() == I.getOperand(2)->getType()) {
+          SDValue LHS = getValue(I.getOperand(1));
+          SDValue RHS = getValue(I.getOperand(2));
+          setValue(&I, DAG.getNode(ISD::FCOPYSIGN, getCurDebugLoc(),
+                                   LHS.getValueType(), LHS, RHS));
+          return;
+        }
+      } else if (Name == "fabs" || Name == "fabsf" || Name == "fabsl") {
+        if (I.getNumOperands() == 2 &&   // Basic sanity checks.
+            I.getOperand(1)->getType()->isFloatingPointTy() &&
+            I.getType() == I.getOperand(1)->getType()) {
+          SDValue Tmp = getValue(I.getOperand(1));
+          setValue(&I, DAG.getNode(ISD::FABS, getCurDebugLoc(),
+                                   Tmp.getValueType(), Tmp));
+          return;
+        }
+      } else if (Name == "sin" || Name == "sinf" || Name == "sinl") {
+        if (I.getNumOperands() == 2 &&   // Basic sanity checks.
+            I.getOperand(1)->getType()->isFloatingPointTy() &&
+            I.getType() == I.getOperand(1)->getType() &&
+            I.onlyReadsMemory()) {
+          SDValue Tmp = getValue(I.getOperand(1));
+          setValue(&I, DAG.getNode(ISD::FSIN, getCurDebugLoc(),
+                                   Tmp.getValueType(), Tmp));
+          return;
+        }
+      } else if (Name == "cos" || Name == "cosf" || Name == "cosl") {
+        if (I.getNumOperands() == 2 &&   // Basic sanity checks.
+            I.getOperand(1)->getType()->isFloatingPointTy() &&
+            I.getType() == I.getOperand(1)->getType() &&
+            I.onlyReadsMemory()) {
+          SDValue Tmp = getValue(I.getOperand(1));
+          setValue(&I, DAG.getNode(ISD::FCOS, getCurDebugLoc(),
+                                   Tmp.getValueType(), Tmp));
+          return;
+        }
+      } else if (Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl") {
+        if (I.getNumOperands() == 2 &&   // Basic sanity checks.
+            I.getOperand(1)->getType()->isFloatingPointTy() &&
+            I.getType() == I.getOperand(1)->getType() &&
+            I.onlyReadsMemory()) {
+          SDValue Tmp = getValue(I.getOperand(1));
+          setValue(&I, DAG.getNode(ISD::FSQRT, getCurDebugLoc(),
+                                   Tmp.getValueType(), Tmp));
+          return;
+        }
+      } else if (Name == "memcmp") {
+        if (visitMemCmpCall(I))
+          return;
       }
+    }
+  } else if (isa<InlineAsm>(I.getOperand(0))) {
+    visitInlineAsm(&I);
+    return;
   }
-  return FoundRC;
-}
 
+  SDValue Callee;
+  if (!RenameFn)
+    Callee = getValue(I.getOperand(0));
+  else
+    Callee = DAG.getExternalSymbol(RenameFn, TLI.getPointerTy());
+
+  // Check if we can potentially perform a tail call. More detailed checking is
+  // be done within LowerCallTo, after more information about the call is known.
+  LowerCallTo(&I, Callee, I.isTailCall());
+}
 
 namespace llvm {
+
 /// AsmOperandInfo - This contains information for each constraint that we are
 /// lowering.
 class LLVM_LIBRARY_VISIBILITY SDISelAsmOperandInfo :
@@ -5044,8 +4994,56 @@
         Regs.insert(*Aliases);
   }
 };
+
 } // end llvm namespace.
 
+/// isAllocatableRegister - If the specified register is safe to allocate,
+/// i.e. it isn't a stack pointer or some other special register, return the
+/// register class for the register.  Otherwise, return null.
+static const TargetRegisterClass *
+isAllocatableRegister(unsigned Reg, MachineFunction &MF,
+                      const TargetLowering &TLI,
+                      const TargetRegisterInfo *TRI) {
+  EVT FoundVT = MVT::Other;
+  const TargetRegisterClass *FoundRC = 0;
+  for (TargetRegisterInfo::regclass_iterator RCI = TRI->regclass_begin(),
+       E = TRI->regclass_end(); RCI != E; ++RCI) {
+    EVT ThisVT = MVT::Other;
+
+    const TargetRegisterClass *RC = *RCI;
+    // If none of the value types for this register class are valid, we
+    // can't use it.  For example, 64-bit reg classes on 32-bit targets.
+    for (TargetRegisterClass::vt_iterator I = RC->vt_begin(), E = RC->vt_end();
+         I != E; ++I) {
+      if (TLI.isTypeLegal(*I)) {
+        // If we have already found this register in a different register class,
+        // choose the one with the largest VT specified.  For example, on
+        // PowerPC, we favor f64 register classes over f32.
+        if (FoundVT == MVT::Other || FoundVT.bitsLT(*I)) {
+          ThisVT = *I;
+          break;
+        }
+      }
+    }
+
+    if (ThisVT == MVT::Other) continue;
+
+    // NOTE: This isn't ideal.  In particular, this might allocate the
+    // frame pointer in functions that need it (due to them not being taken
+    // out of allocation, because a variable sized allocation hasn't been seen
+    // yet).  This is a slight code pessimization, but should still work.
+    for (TargetRegisterClass::iterator I = RC->allocation_order_begin(MF),
+         E = RC->allocation_order_end(MF); I != E; ++I)
+      if (*I == Reg) {
+        // We found a matching register class.  Keep looking at others in case
+        // we find one with larger registers that this physreg is also in.
+        FoundRC = RC;
+        FoundVT = ThisVT;
+        break;
+      }
+  }
+  return FoundRC;
+}
 
 /// GetRegistersForValue - Assign registers (virtual or physical) for the
 /// specified operand.  We prefer to assign virtual registers, to allow the





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