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      1 //===-- LegalizeDAG.cpp - Implement SelectionDAG::Legalize ----------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file implements the SelectionDAG::Legalize method.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "llvm/Analysis/DebugInfo.h"
     15 #include "llvm/CodeGen/Analysis.h"
     16 #include "llvm/CodeGen/MachineFunction.h"
     17 #include "llvm/CodeGen/MachineJumpTableInfo.h"
     18 #include "llvm/CodeGen/SelectionDAG.h"
     19 #include "llvm/Target/TargetFrameLowering.h"
     20 #include "llvm/Target/TargetLowering.h"
     21 #include "llvm/Target/TargetData.h"
     22 #include "llvm/Target/TargetMachine.h"
     23 #include "llvm/CallingConv.h"
     24 #include "llvm/Constants.h"
     25 #include "llvm/DerivedTypes.h"
     26 #include "llvm/LLVMContext.h"
     27 #include "llvm/Support/Debug.h"
     28 #include "llvm/Support/ErrorHandling.h"
     29 #include "llvm/Support/MathExtras.h"
     30 #include "llvm/Support/raw_ostream.h"
     31 #include "llvm/ADT/DenseMap.h"
     32 #include "llvm/ADT/SmallVector.h"
     33 #include "llvm/ADT/SmallPtrSet.h"
     34 using namespace llvm;
     35 
     36 //===----------------------------------------------------------------------===//
     37 /// SelectionDAGLegalize - This takes an arbitrary SelectionDAG as input and
     38 /// hacks on it until the target machine can handle it.  This involves
     39 /// eliminating value sizes the machine cannot handle (promoting small sizes to
     40 /// large sizes or splitting up large values into small values) as well as
     41 /// eliminating operations the machine cannot handle.
     42 ///
     43 /// This code also does a small amount of optimization and recognition of idioms
     44 /// as part of its processing.  For example, if a target does not support a
     45 /// 'setcc' instruction efficiently, but does support 'brcc' instruction, this
     46 /// will attempt merge setcc and brc instructions into brcc's.
     47 ///
     48 namespace {
     49 class SelectionDAGLegalize {
     50   const TargetMachine &TM;
     51   const TargetLowering &TLI;
     52   SelectionDAG &DAG;
     53 
     54   // Libcall insertion helpers.
     55 
     56   /// LastCALLSEQ_END - This keeps track of the CALLSEQ_END node that has been
     57   /// legalized.  We use this to ensure that calls are properly serialized
     58   /// against each other, including inserted libcalls.
     59   SDValue LastCALLSEQ_END;
     60 
     61   /// IsLegalizingCall - This member is used *only* for purposes of providing
     62   /// helpful assertions that a libcall isn't created while another call is
     63   /// being legalized (which could lead to non-serialized call sequences).
     64   bool IsLegalizingCall;
     65 
     66   /// LegalizedNodes - For nodes that are of legal width, and that have more
     67   /// than one use, this map indicates what regularized operand to use.  This
     68   /// allows us to avoid legalizing the same thing more than once.
     69   DenseMap<SDValue, SDValue> LegalizedNodes;
     70 
     71   void AddLegalizedOperand(SDValue From, SDValue To) {
     72     LegalizedNodes.insert(std::make_pair(From, To));
     73     // If someone requests legalization of the new node, return itself.
     74     if (From != To)
     75       LegalizedNodes.insert(std::make_pair(To, To));
     76 
     77     // Transfer SDDbgValues.
     78     DAG.TransferDbgValues(From, To);
     79   }
     80 
     81 public:
     82   explicit SelectionDAGLegalize(SelectionDAG &DAG);
     83 
     84   void LegalizeDAG();
     85 
     86 private:
     87   /// LegalizeOp - Return a legal replacement for the given operation, with
     88   /// all legal operands.
     89   SDValue LegalizeOp(SDValue O);
     90 
     91   SDValue OptimizeFloatStore(StoreSDNode *ST);
     92 
     93   /// PerformInsertVectorEltInMemory - Some target cannot handle a variable
     94   /// insertion index for the INSERT_VECTOR_ELT instruction.  In this case, it
     95   /// is necessary to spill the vector being inserted into to memory, perform
     96   /// the insert there, and then read the result back.
     97   SDValue PerformInsertVectorEltInMemory(SDValue Vec, SDValue Val,
     98                                          SDValue Idx, DebugLoc dl);
     99   SDValue ExpandINSERT_VECTOR_ELT(SDValue Vec, SDValue Val,
    100                                   SDValue Idx, DebugLoc dl);
    101 
    102   /// ShuffleWithNarrowerEltType - Return a vector shuffle operation which
    103   /// performs the same shuffe in terms of order or result bytes, but on a type
    104   /// whose vector element type is narrower than the original shuffle type.
    105   /// e.g. <v4i32> <0, 1, 0, 1> -> v8i16 <0, 1, 2, 3, 0, 1, 2, 3>
    106   SDValue ShuffleWithNarrowerEltType(EVT NVT, EVT VT, DebugLoc dl,
    107                                      SDValue N1, SDValue N2,
    108                                      SmallVectorImpl<int> &Mask) const;
    109 
    110   bool LegalizeAllNodesNotLeadingTo(SDNode *N, SDNode *Dest,
    111                                     SmallPtrSet<SDNode*, 32> &NodesLeadingTo);
    112 
    113   void LegalizeSetCCCondCode(EVT VT, SDValue &LHS, SDValue &RHS, SDValue &CC,
    114                              DebugLoc dl);
    115 
    116   SDValue ExpandLibCall(RTLIB::Libcall LC, SDNode *Node, bool isSigned);
    117   SDValue ExpandLibCall(RTLIB::Libcall LC, EVT RetVT, const SDValue *Ops,
    118                         unsigned NumOps, bool isSigned, DebugLoc dl);
    119 
    120   std::pair<SDValue, SDValue> ExpandChainLibCall(RTLIB::Libcall LC,
    121                                                  SDNode *Node, bool isSigned);
    122   SDValue ExpandFPLibCall(SDNode *Node, RTLIB::Libcall Call_F32,
    123                           RTLIB::Libcall Call_F64, RTLIB::Libcall Call_F80,
    124                           RTLIB::Libcall Call_PPCF128);
    125   SDValue ExpandIntLibCall(SDNode *Node, bool isSigned,
    126                            RTLIB::Libcall Call_I8,
    127                            RTLIB::Libcall Call_I16,
    128                            RTLIB::Libcall Call_I32,
    129                            RTLIB::Libcall Call_I64,
    130                            RTLIB::Libcall Call_I128);
    131   void ExpandDivRemLibCall(SDNode *Node, SmallVectorImpl<SDValue> &Results);
    132 
    133   SDValue EmitStackConvert(SDValue SrcOp, EVT SlotVT, EVT DestVT, DebugLoc dl);
    134   SDValue ExpandBUILD_VECTOR(SDNode *Node);
    135   SDValue ExpandSCALAR_TO_VECTOR(SDNode *Node);
    136   void ExpandDYNAMIC_STACKALLOC(SDNode *Node,
    137                                 SmallVectorImpl<SDValue> &Results);
    138   SDValue ExpandFCOPYSIGN(SDNode *Node);
    139   SDValue ExpandLegalINT_TO_FP(bool isSigned, SDValue LegalOp, EVT DestVT,
    140                                DebugLoc dl);
    141   SDValue PromoteLegalINT_TO_FP(SDValue LegalOp, EVT DestVT, bool isSigned,
    142                                 DebugLoc dl);
    143   SDValue PromoteLegalFP_TO_INT(SDValue LegalOp, EVT DestVT, bool isSigned,
    144                                 DebugLoc dl);
    145 
    146   SDValue ExpandBSWAP(SDValue Op, DebugLoc dl);
    147   SDValue ExpandBitCount(unsigned Opc, SDValue Op, DebugLoc dl);
    148 
    149   SDValue ExpandExtractFromVectorThroughStack(SDValue Op);
    150   SDValue ExpandInsertToVectorThroughStack(SDValue Op);
    151   SDValue ExpandVectorBuildThroughStack(SDNode* Node);
    152 
    153   std::pair<SDValue, SDValue> ExpandAtomic(SDNode *Node);
    154 
    155   void ExpandNode(SDNode *Node, SmallVectorImpl<SDValue> &Results);
    156   void PromoteNode(SDNode *Node, SmallVectorImpl<SDValue> &Results);
    157 };
    158 }
    159 
    160 /// ShuffleWithNarrowerEltType - Return a vector shuffle operation which
    161 /// performs the same shuffe in terms of order or result bytes, but on a type
    162 /// whose vector element type is narrower than the original shuffle type.
    163 /// e.g. <v4i32> <0, 1, 0, 1> -> v8i16 <0, 1, 2, 3, 0, 1, 2, 3>
    164 SDValue
    165 SelectionDAGLegalize::ShuffleWithNarrowerEltType(EVT NVT, EVT VT,  DebugLoc dl,
    166                                                  SDValue N1, SDValue N2,
    167                                              SmallVectorImpl<int> &Mask) const {
    168   unsigned NumMaskElts = VT.getVectorNumElements();
    169   unsigned NumDestElts = NVT.getVectorNumElements();
    170   unsigned NumEltsGrowth = NumDestElts / NumMaskElts;
    171 
    172   assert(NumEltsGrowth && "Cannot promote to vector type with fewer elts!");
    173 
    174   if (NumEltsGrowth == 1)
    175     return DAG.getVectorShuffle(NVT, dl, N1, N2, &Mask[0]);
    176 
    177   SmallVector<int, 8> NewMask;
    178   for (unsigned i = 0; i != NumMaskElts; ++i) {
    179     int Idx = Mask[i];
    180     for (unsigned j = 0; j != NumEltsGrowth; ++j) {
    181       if (Idx < 0)
    182         NewMask.push_back(-1);
    183       else
    184         NewMask.push_back(Idx * NumEltsGrowth + j);
    185     }
    186   }
    187   assert(NewMask.size() == NumDestElts && "Non-integer NumEltsGrowth?");
    188   assert(TLI.isShuffleMaskLegal(NewMask, NVT) && "Shuffle not legal?");
    189   return DAG.getVectorShuffle(NVT, dl, N1, N2, &NewMask[0]);
    190 }
    191 
    192 SelectionDAGLegalize::SelectionDAGLegalize(SelectionDAG &dag)
    193   : TM(dag.getTarget()), TLI(dag.getTargetLoweringInfo()),
    194     DAG(dag) {
    195 }
    196 
    197 void SelectionDAGLegalize::LegalizeDAG() {
    198   LastCALLSEQ_END = DAG.getEntryNode();
    199   IsLegalizingCall = false;
    200 
    201   // The legalize process is inherently a bottom-up recursive process (users
    202   // legalize their uses before themselves).  Given infinite stack space, we
    203   // could just start legalizing on the root and traverse the whole graph.  In
    204   // practice however, this causes us to run out of stack space on large basic
    205   // blocks.  To avoid this problem, compute an ordering of the nodes where each
    206   // node is only legalized after all of its operands are legalized.
    207   DAG.AssignTopologicalOrder();
    208   for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
    209        E = prior(DAG.allnodes_end()); I != llvm::next(E); ++I)
    210     LegalizeOp(SDValue(I, 0));
    211 
    212   // Finally, it's possible the root changed.  Get the new root.
    213   SDValue OldRoot = DAG.getRoot();
    214   assert(LegalizedNodes.count(OldRoot) && "Root didn't get legalized?");
    215   DAG.setRoot(LegalizedNodes[OldRoot]);
    216 
    217   LegalizedNodes.clear();
    218 
    219   // Remove dead nodes now.
    220   DAG.RemoveDeadNodes();
    221 }
    222 
    223 
    224 /// FindCallEndFromCallStart - Given a chained node that is part of a call
    225 /// sequence, find the CALLSEQ_END node that terminates the call sequence.
    226 static SDNode *FindCallEndFromCallStart(SDNode *Node, int depth = 0) {
    227   // Nested CALLSEQ_START/END constructs aren't yet legal,
    228   // but we can DTRT and handle them correctly here.
    229   if (Node->getOpcode() == ISD::CALLSEQ_START)
    230     depth++;
    231   else if (Node->getOpcode() == ISD::CALLSEQ_END) {
    232     depth--;
    233     if (depth == 0)
    234       return Node;
    235   }
    236   if (Node->use_empty())
    237     return 0;   // No CallSeqEnd
    238 
    239   // The chain is usually at the end.
    240   SDValue TheChain(Node, Node->getNumValues()-1);
    241   if (TheChain.getValueType() != MVT::Other) {
    242     // Sometimes it's at the beginning.
    243     TheChain = SDValue(Node, 0);
    244     if (TheChain.getValueType() != MVT::Other) {
    245       // Otherwise, hunt for it.
    246       for (unsigned i = 1, e = Node->getNumValues(); i != e; ++i)
    247         if (Node->getValueType(i) == MVT::Other) {
    248           TheChain = SDValue(Node, i);
    249           break;
    250         }
    251 
    252       // Otherwise, we walked into a node without a chain.
    253       if (TheChain.getValueType() != MVT::Other)
    254         return 0;
    255     }
    256   }
    257 
    258   for (SDNode::use_iterator UI = Node->use_begin(),
    259        E = Node->use_end(); UI != E; ++UI) {
    260 
    261     // Make sure to only follow users of our token chain.
    262     SDNode *User = *UI;
    263     for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i)
    264       if (User->getOperand(i) == TheChain)
    265         if (SDNode *Result = FindCallEndFromCallStart(User, depth))
    266           return Result;
    267   }
    268   return 0;
    269 }
    270 
    271 /// FindCallStartFromCallEnd - Given a chained node that is part of a call
    272 /// sequence, find the CALLSEQ_START node that initiates the call sequence.
    273 static SDNode *FindCallStartFromCallEnd(SDNode *Node) {
    274   int nested = 0;
    275   assert(Node && "Didn't find callseq_start for a call??");
    276   while (Node->getOpcode() != ISD::CALLSEQ_START || nested) {
    277     Node = Node->getOperand(0).getNode();
    278     assert(Node->getOperand(0).getValueType() == MVT::Other &&
    279            "Node doesn't have a token chain argument!");
    280     switch (Node->getOpcode()) {
    281     default:
    282       break;
    283     case ISD::CALLSEQ_START:
    284       if (!nested)
    285         return Node;
    286       nested--;
    287       break;
    288     case ISD::CALLSEQ_END:
    289       nested++;
    290       break;
    291     }
    292   }
    293   return 0;
    294 }
    295 
    296 /// LegalizeAllNodesNotLeadingTo - Recursively walk the uses of N, looking to
    297 /// see if any uses can reach Dest.  If no dest operands can get to dest,
    298 /// legalize them, legalize ourself, and return false, otherwise, return true.
    299 ///
    300 /// Keep track of the nodes we fine that actually do lead to Dest in
    301 /// NodesLeadingTo.  This avoids retraversing them exponential number of times.
    302 ///
    303 bool SelectionDAGLegalize::LegalizeAllNodesNotLeadingTo(SDNode *N, SDNode *Dest,
    304                                      SmallPtrSet<SDNode*, 32> &NodesLeadingTo) {
    305   if (N == Dest) return true;  // N certainly leads to Dest :)
    306 
    307   // If we've already processed this node and it does lead to Dest, there is no
    308   // need to reprocess it.
    309   if (NodesLeadingTo.count(N)) return true;
    310 
    311   // If the first result of this node has been already legalized, then it cannot
    312   // reach N.
    313   if (LegalizedNodes.count(SDValue(N, 0))) return false;
    314 
    315   // Okay, this node has not already been legalized.  Check and legalize all
    316   // operands.  If none lead to Dest, then we can legalize this node.
    317   bool OperandsLeadToDest = false;
    318   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
    319     OperandsLeadToDest |=     // If an operand leads to Dest, so do we.
    320       LegalizeAllNodesNotLeadingTo(N->getOperand(i).getNode(), Dest,
    321                                    NodesLeadingTo);
    322 
    323   if (OperandsLeadToDest) {
    324     NodesLeadingTo.insert(N);
    325     return true;
    326   }
    327 
    328   // Okay, this node looks safe, legalize it and return false.
    329   LegalizeOp(SDValue(N, 0));
    330   return false;
    331 }
    332 
    333 /// ExpandConstantFP - Expands the ConstantFP node to an integer constant or
    334 /// a load from the constant pool.
    335 static SDValue ExpandConstantFP(ConstantFPSDNode *CFP, bool UseCP,
    336                                 SelectionDAG &DAG, const TargetLowering &TLI) {
    337   bool Extend = false;
    338   DebugLoc dl = CFP->getDebugLoc();
    339 
    340   // If a FP immediate is precise when represented as a float and if the
    341   // target can do an extending load from float to double, we put it into
    342   // the constant pool as a float, even if it's is statically typed as a
    343   // double.  This shrinks FP constants and canonicalizes them for targets where
    344   // an FP extending load is the same cost as a normal load (such as on the x87
    345   // fp stack or PPC FP unit).
    346   EVT VT = CFP->getValueType(0);
    347   ConstantFP *LLVMC = const_cast<ConstantFP*>(CFP->getConstantFPValue());
    348   if (!UseCP) {
    349     assert((VT == MVT::f64 || VT == MVT::f32) && "Invalid type expansion");
    350     return DAG.getConstant(LLVMC->getValueAPF().bitcastToAPInt(),
    351                            (VT == MVT::f64) ? MVT::i64 : MVT::i32);
    352   }
    353 
    354   EVT OrigVT = VT;
    355   EVT SVT = VT;
    356   while (SVT != MVT::f32) {
    357     SVT = (MVT::SimpleValueType)(SVT.getSimpleVT().SimpleTy - 1);
    358     if (ConstantFPSDNode::isValueValidForType(SVT, CFP->getValueAPF()) &&
    359         // Only do this if the target has a native EXTLOAD instruction from
    360         // smaller type.
    361         TLI.isLoadExtLegal(ISD::EXTLOAD, SVT) &&
    362         TLI.ShouldShrinkFPConstant(OrigVT)) {
    363       Type *SType = SVT.getTypeForEVT(*DAG.getContext());
    364       LLVMC = cast<ConstantFP>(ConstantExpr::getFPTrunc(LLVMC, SType));
    365       VT = SVT;
    366       Extend = true;
    367     }
    368   }
    369 
    370   SDValue CPIdx = DAG.getConstantPool(LLVMC, TLI.getPointerTy());
    371   unsigned Alignment = cast<ConstantPoolSDNode>(CPIdx)->getAlignment();
    372   if (Extend)
    373     return DAG.getExtLoad(ISD::EXTLOAD, dl, OrigVT,
    374                           DAG.getEntryNode(),
    375                           CPIdx, MachinePointerInfo::getConstantPool(),
    376                           VT, false, false, Alignment);
    377   return DAG.getLoad(OrigVT, dl, DAG.getEntryNode(), CPIdx,
    378                      MachinePointerInfo::getConstantPool(), false, false,
    379                      Alignment);
    380 }
    381 
    382 /// ExpandUnalignedStore - Expands an unaligned store to 2 half-size stores.
    383 static
    384 SDValue ExpandUnalignedStore(StoreSDNode *ST, SelectionDAG &DAG,
    385                              const TargetLowering &TLI) {
    386   SDValue Chain = ST->getChain();
    387   SDValue Ptr = ST->getBasePtr();
    388   SDValue Val = ST->getValue();
    389   EVT VT = Val.getValueType();
    390   int Alignment = ST->getAlignment();
    391   DebugLoc dl = ST->getDebugLoc();
    392   if (ST->getMemoryVT().isFloatingPoint() ||
    393       ST->getMemoryVT().isVector()) {
    394     EVT intVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits());
    395     if (TLI.isTypeLegal(intVT)) {
    396       // Expand to a bitconvert of the value to the integer type of the
    397       // same size, then a (misaligned) int store.
    398       // FIXME: Does not handle truncating floating point stores!
    399       SDValue Result = DAG.getNode(ISD::BITCAST, dl, intVT, Val);
    400       return DAG.getStore(Chain, dl, Result, Ptr, ST->getPointerInfo(),
    401                           ST->isVolatile(), ST->isNonTemporal(), Alignment);
    402     }
    403     // Do a (aligned) store to a stack slot, then copy from the stack slot
    404     // to the final destination using (unaligned) integer loads and stores.
    405     EVT StoredVT = ST->getMemoryVT();
    406     EVT RegVT =
    407       TLI.getRegisterType(*DAG.getContext(),
    408                           EVT::getIntegerVT(*DAG.getContext(),
    409                                             StoredVT.getSizeInBits()));
    410     unsigned StoredBytes = StoredVT.getSizeInBits() / 8;
    411     unsigned RegBytes = RegVT.getSizeInBits() / 8;
    412     unsigned NumRegs = (StoredBytes + RegBytes - 1) / RegBytes;
    413 
    414     // Make sure the stack slot is also aligned for the register type.
    415     SDValue StackPtr = DAG.CreateStackTemporary(StoredVT, RegVT);
    416 
    417     // Perform the original store, only redirected to the stack slot.
    418     SDValue Store = DAG.getTruncStore(Chain, dl,
    419                                       Val, StackPtr, MachinePointerInfo(),
    420                                       StoredVT, false, false, 0);
    421     SDValue Increment = DAG.getConstant(RegBytes, TLI.getPointerTy());
    422     SmallVector<SDValue, 8> Stores;
    423     unsigned Offset = 0;
    424 
    425     // Do all but one copies using the full register width.
    426     for (unsigned i = 1; i < NumRegs; i++) {
    427       // Load one integer register's worth from the stack slot.
    428       SDValue Load = DAG.getLoad(RegVT, dl, Store, StackPtr,
    429                                  MachinePointerInfo(),
    430                                  false, false, 0);
    431       // Store it to the final location.  Remember the store.
    432       Stores.push_back(DAG.getStore(Load.getValue(1), dl, Load, Ptr,
    433                                   ST->getPointerInfo().getWithOffset(Offset),
    434                                     ST->isVolatile(), ST->isNonTemporal(),
    435                                     MinAlign(ST->getAlignment(), Offset)));
    436       // Increment the pointers.
    437       Offset += RegBytes;
    438       StackPtr = DAG.getNode(ISD::ADD, dl, StackPtr.getValueType(), StackPtr,
    439                              Increment);
    440       Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr, Increment);
    441     }
    442 
    443     // The last store may be partial.  Do a truncating store.  On big-endian
    444     // machines this requires an extending load from the stack slot to ensure
    445     // that the bits are in the right place.
    446     EVT MemVT = EVT::getIntegerVT(*DAG.getContext(),
    447                                   8 * (StoredBytes - Offset));
    448 
    449     // Load from the stack slot.
    450     SDValue Load = DAG.getExtLoad(ISD::EXTLOAD, dl, RegVT, Store, StackPtr,
    451                                   MachinePointerInfo(),
    452                                   MemVT, false, false, 0);
    453 
    454     Stores.push_back(DAG.getTruncStore(Load.getValue(1), dl, Load, Ptr,
    455                                        ST->getPointerInfo()
    456                                          .getWithOffset(Offset),
    457                                        MemVT, ST->isVolatile(),
    458                                        ST->isNonTemporal(),
    459                                        MinAlign(ST->getAlignment(), Offset)));
    460     // The order of the stores doesn't matter - say it with a TokenFactor.
    461     return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &Stores[0],
    462                        Stores.size());
    463   }
    464   assert(ST->getMemoryVT().isInteger() &&
    465          !ST->getMemoryVT().isVector() &&
    466          "Unaligned store of unknown type.");
    467   // Get the half-size VT
    468   EVT NewStoredVT = ST->getMemoryVT().getHalfSizedIntegerVT(*DAG.getContext());
    469   int NumBits = NewStoredVT.getSizeInBits();
    470   int IncrementSize = NumBits / 8;
    471 
    472   // Divide the stored value in two parts.
    473   SDValue ShiftAmount = DAG.getConstant(NumBits,
    474                                       TLI.getShiftAmountTy(Val.getValueType()));
    475   SDValue Lo = Val;
    476   SDValue Hi = DAG.getNode(ISD::SRL, dl, VT, Val, ShiftAmount);
    477 
    478   // Store the two parts
    479   SDValue Store1, Store2;
    480   Store1 = DAG.getTruncStore(Chain, dl, TLI.isLittleEndian()?Lo:Hi, Ptr,
    481                              ST->getPointerInfo(), NewStoredVT,
    482                              ST->isVolatile(), ST->isNonTemporal(), Alignment);
    483   Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
    484                     DAG.getConstant(IncrementSize, TLI.getPointerTy()));
    485   Alignment = MinAlign(Alignment, IncrementSize);
    486   Store2 = DAG.getTruncStore(Chain, dl, TLI.isLittleEndian()?Hi:Lo, Ptr,
    487                              ST->getPointerInfo().getWithOffset(IncrementSize),
    488                              NewStoredVT, ST->isVolatile(), ST->isNonTemporal(),
    489                              Alignment);
    490 
    491   return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Store1, Store2);
    492 }
    493 
    494 /// ExpandUnalignedLoad - Expands an unaligned load to 2 half-size loads.
    495 static
    496 SDValue ExpandUnalignedLoad(LoadSDNode *LD, SelectionDAG &DAG,
    497                             const TargetLowering &TLI) {
    498   SDValue Chain = LD->getChain();
    499   SDValue Ptr = LD->getBasePtr();
    500   EVT VT = LD->getValueType(0);
    501   EVT LoadedVT = LD->getMemoryVT();
    502   DebugLoc dl = LD->getDebugLoc();
    503   if (VT.isFloatingPoint() || VT.isVector()) {
    504     EVT intVT = EVT::getIntegerVT(*DAG.getContext(), LoadedVT.getSizeInBits());
    505     if (TLI.isTypeLegal(intVT)) {
    506       // Expand to a (misaligned) integer load of the same size,
    507       // then bitconvert to floating point or vector.
    508       SDValue newLoad = DAG.getLoad(intVT, dl, Chain, Ptr, LD->getPointerInfo(),
    509                                     LD->isVolatile(),
    510                                     LD->isNonTemporal(), LD->getAlignment());
    511       SDValue Result = DAG.getNode(ISD::BITCAST, dl, LoadedVT, newLoad);
    512       if (VT.isFloatingPoint() && LoadedVT != VT)
    513         Result = DAG.getNode(ISD::FP_EXTEND, dl, VT, Result);
    514 
    515       SDValue Ops[] = { Result, Chain };
    516       return DAG.getMergeValues(Ops, 2, dl);
    517     }
    518 
    519     // Copy the value to a (aligned) stack slot using (unaligned) integer
    520     // loads and stores, then do a (aligned) load from the stack slot.
    521     EVT RegVT = TLI.getRegisterType(*DAG.getContext(), intVT);
    522     unsigned LoadedBytes = LoadedVT.getSizeInBits() / 8;
    523     unsigned RegBytes = RegVT.getSizeInBits() / 8;
    524     unsigned NumRegs = (LoadedBytes + RegBytes - 1) / RegBytes;
    525 
    526     // Make sure the stack slot is also aligned for the register type.
    527     SDValue StackBase = DAG.CreateStackTemporary(LoadedVT, RegVT);
    528 
    529     SDValue Increment = DAG.getConstant(RegBytes, TLI.getPointerTy());
    530     SmallVector<SDValue, 8> Stores;
    531     SDValue StackPtr = StackBase;
    532     unsigned Offset = 0;
    533 
    534     // Do all but one copies using the full register width.
    535     for (unsigned i = 1; i < NumRegs; i++) {
    536       // Load one integer register's worth from the original location.
    537       SDValue Load = DAG.getLoad(RegVT, dl, Chain, Ptr,
    538                                  LD->getPointerInfo().getWithOffset(Offset),
    539                                  LD->isVolatile(), LD->isNonTemporal(),
    540                                  MinAlign(LD->getAlignment(), Offset));
    541       // Follow the load with a store to the stack slot.  Remember the store.
    542       Stores.push_back(DAG.getStore(Load.getValue(1), dl, Load, StackPtr,
    543                                     MachinePointerInfo(), false, false, 0));
    544       // Increment the pointers.
    545       Offset += RegBytes;
    546       Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr, Increment);
    547       StackPtr = DAG.getNode(ISD::ADD, dl, StackPtr.getValueType(), StackPtr,
    548                              Increment);
    549     }
    550 
    551     // The last copy may be partial.  Do an extending load.
    552     EVT MemVT = EVT::getIntegerVT(*DAG.getContext(),
    553                                   8 * (LoadedBytes - Offset));
    554     SDValue Load = DAG.getExtLoad(ISD::EXTLOAD, dl, RegVT, Chain, Ptr,
    555                                   LD->getPointerInfo().getWithOffset(Offset),
    556                                   MemVT, LD->isVolatile(),
    557                                   LD->isNonTemporal(),
    558                                   MinAlign(LD->getAlignment(), Offset));
    559     // Follow the load with a store to the stack slot.  Remember the store.
    560     // On big-endian machines this requires a truncating store to ensure
    561     // that the bits end up in the right place.
    562     Stores.push_back(DAG.getTruncStore(Load.getValue(1), dl, Load, StackPtr,
    563                                        MachinePointerInfo(), MemVT,
    564                                        false, false, 0));
    565 
    566     // The order of the stores doesn't matter - say it with a TokenFactor.
    567     SDValue TF = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &Stores[0],
    568                              Stores.size());
    569 
    570     // Finally, perform the original load only redirected to the stack slot.
    571     Load = DAG.getExtLoad(LD->getExtensionType(), dl, VT, TF, StackBase,
    572                           MachinePointerInfo(), LoadedVT, false, false, 0);
    573 
    574     // Callers expect a MERGE_VALUES node.
    575     SDValue Ops[] = { Load, TF };
    576     return DAG.getMergeValues(Ops, 2, dl);
    577   }
    578   assert(LoadedVT.isInteger() && !LoadedVT.isVector() &&
    579          "Unaligned load of unsupported type.");
    580 
    581   // Compute the new VT that is half the size of the old one.  This is an
    582   // integer MVT.
    583   unsigned NumBits = LoadedVT.getSizeInBits();
    584   EVT NewLoadedVT;
    585   NewLoadedVT = EVT::getIntegerVT(*DAG.getContext(), NumBits/2);
    586   NumBits >>= 1;
    587 
    588   unsigned Alignment = LD->getAlignment();
    589   unsigned IncrementSize = NumBits / 8;
    590   ISD::LoadExtType HiExtType = LD->getExtensionType();
    591 
    592   // If the original load is NON_EXTLOAD, the hi part load must be ZEXTLOAD.
    593   if (HiExtType == ISD::NON_EXTLOAD)
    594     HiExtType = ISD::ZEXTLOAD;
    595 
    596   // Load the value in two parts
    597   SDValue Lo, Hi;
    598   if (TLI.isLittleEndian()) {
    599     Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr, LD->getPointerInfo(),
    600                         NewLoadedVT, LD->isVolatile(),
    601                         LD->isNonTemporal(), Alignment);
    602     Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
    603                       DAG.getConstant(IncrementSize, TLI.getPointerTy()));
    604     Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr,
    605                         LD->getPointerInfo().getWithOffset(IncrementSize),
    606                         NewLoadedVT, LD->isVolatile(),
    607                         LD->isNonTemporal(), MinAlign(Alignment,IncrementSize));
    608   } else {
    609     Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr, LD->getPointerInfo(),
    610                         NewLoadedVT, LD->isVolatile(),
    611                         LD->isNonTemporal(), Alignment);
    612     Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
    613                       DAG.getConstant(IncrementSize, TLI.getPointerTy()));
    614     Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr,
    615                         LD->getPointerInfo().getWithOffset(IncrementSize),
    616                         NewLoadedVT, LD->isVolatile(),
    617                         LD->isNonTemporal(), MinAlign(Alignment,IncrementSize));
    618   }
    619 
    620   // aggregate the two parts
    621   SDValue ShiftAmount = DAG.getConstant(NumBits,
    622                                        TLI.getShiftAmountTy(Hi.getValueType()));
    623   SDValue Result = DAG.getNode(ISD::SHL, dl, VT, Hi, ShiftAmount);
    624   Result = DAG.getNode(ISD::OR, dl, VT, Result, Lo);
    625 
    626   SDValue TF = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
    627                              Hi.getValue(1));
    628 
    629   SDValue Ops[] = { Result, TF };
    630   return DAG.getMergeValues(Ops, 2, dl);
    631 }
    632 
    633 /// PerformInsertVectorEltInMemory - Some target cannot handle a variable
    634 /// insertion index for the INSERT_VECTOR_ELT instruction.  In this case, it
    635 /// is necessary to spill the vector being inserted into to memory, perform
    636 /// the insert there, and then read the result back.
    637 SDValue SelectionDAGLegalize::
    638 PerformInsertVectorEltInMemory(SDValue Vec, SDValue Val, SDValue Idx,
    639                                DebugLoc dl) {
    640   SDValue Tmp1 = Vec;
    641   SDValue Tmp2 = Val;
    642   SDValue Tmp3 = Idx;
    643 
    644   // If the target doesn't support this, we have to spill the input vector
    645   // to a temporary stack slot, update the element, then reload it.  This is
    646   // badness.  We could also load the value into a vector register (either
    647   // with a "move to register" or "extload into register" instruction, then
    648   // permute it into place, if the idx is a constant and if the idx is
    649   // supported by the target.
    650   EVT VT    = Tmp1.getValueType();
    651   EVT EltVT = VT.getVectorElementType();
    652   EVT IdxVT = Tmp3.getValueType();
    653   EVT PtrVT = TLI.getPointerTy();
    654   SDValue StackPtr = DAG.CreateStackTemporary(VT);
    655 
    656   int SPFI = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
    657 
    658   // Store the vector.
    659   SDValue Ch = DAG.getStore(DAG.getEntryNode(), dl, Tmp1, StackPtr,
    660                             MachinePointerInfo::getFixedStack(SPFI),
    661                             false, false, 0);
    662 
    663   // Truncate or zero extend offset to target pointer type.
    664   unsigned CastOpc = IdxVT.bitsGT(PtrVT) ? ISD::TRUNCATE : ISD::ZERO_EXTEND;
    665   Tmp3 = DAG.getNode(CastOpc, dl, PtrVT, Tmp3);
    666   // Add the offset to the index.
    667   unsigned EltSize = EltVT.getSizeInBits()/8;
    668   Tmp3 = DAG.getNode(ISD::MUL, dl, IdxVT, Tmp3,DAG.getConstant(EltSize, IdxVT));
    669   SDValue StackPtr2 = DAG.getNode(ISD::ADD, dl, IdxVT, Tmp3, StackPtr);
    670   // Store the scalar value.
    671   Ch = DAG.getTruncStore(Ch, dl, Tmp2, StackPtr2, MachinePointerInfo(), EltVT,
    672                          false, false, 0);
    673   // Load the updated vector.
    674   return DAG.getLoad(VT, dl, Ch, StackPtr,
    675                      MachinePointerInfo::getFixedStack(SPFI), false, false, 0);
    676 }
    677 
    678 
    679 SDValue SelectionDAGLegalize::
    680 ExpandINSERT_VECTOR_ELT(SDValue Vec, SDValue Val, SDValue Idx, DebugLoc dl) {
    681   if (ConstantSDNode *InsertPos = dyn_cast<ConstantSDNode>(Idx)) {
    682     // SCALAR_TO_VECTOR requires that the type of the value being inserted
    683     // match the element type of the vector being created, except for
    684     // integers in which case the inserted value can be over width.
    685     EVT EltVT = Vec.getValueType().getVectorElementType();
    686     if (Val.getValueType() == EltVT ||
    687         (EltVT.isInteger() && Val.getValueType().bitsGE(EltVT))) {
    688       SDValue ScVec = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl,
    689                                   Vec.getValueType(), Val);
    690 
    691       unsigned NumElts = Vec.getValueType().getVectorNumElements();
    692       // We generate a shuffle of InVec and ScVec, so the shuffle mask
    693       // should be 0,1,2,3,4,5... with the appropriate element replaced with
    694       // elt 0 of the RHS.
    695       SmallVector<int, 8> ShufOps;
    696       for (unsigned i = 0; i != NumElts; ++i)
    697         ShufOps.push_back(i != InsertPos->getZExtValue() ? i : NumElts);
    698 
    699       return DAG.getVectorShuffle(Vec.getValueType(), dl, Vec, ScVec,
    700                                   &ShufOps[0]);
    701     }
    702   }
    703   return PerformInsertVectorEltInMemory(Vec, Val, Idx, dl);
    704 }
    705 
    706 SDValue SelectionDAGLegalize::OptimizeFloatStore(StoreSDNode* ST) {
    707   // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr'
    708   // FIXME: We shouldn't do this for TargetConstantFP's.
    709   // FIXME: move this to the DAG Combiner!  Note that we can't regress due
    710   // to phase ordering between legalized code and the dag combiner.  This
    711   // probably means that we need to integrate dag combiner and legalizer
    712   // together.
    713   // We generally can't do this one for long doubles.
    714   SDValue Tmp1 = ST->getChain();
    715   SDValue Tmp2 = ST->getBasePtr();
    716   SDValue Tmp3;
    717   unsigned Alignment = ST->getAlignment();
    718   bool isVolatile = ST->isVolatile();
    719   bool isNonTemporal = ST->isNonTemporal();
    720   DebugLoc dl = ST->getDebugLoc();
    721   if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(ST->getValue())) {
    722     if (CFP->getValueType(0) == MVT::f32 &&
    723         TLI.isTypeLegal(MVT::i32)) {
    724       Tmp3 = DAG.getConstant(CFP->getValueAPF().
    725                                       bitcastToAPInt().zextOrTrunc(32),
    726                               MVT::i32);
    727       return DAG.getStore(Tmp1, dl, Tmp3, Tmp2, ST->getPointerInfo(),
    728                           isVolatile, isNonTemporal, Alignment);
    729     }
    730 
    731     if (CFP->getValueType(0) == MVT::f64) {
    732       // If this target supports 64-bit registers, do a single 64-bit store.
    733       if (TLI.isTypeLegal(MVT::i64)) {
    734         Tmp3 = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt().
    735                                   zextOrTrunc(64), MVT::i64);
    736         return DAG.getStore(Tmp1, dl, Tmp3, Tmp2, ST->getPointerInfo(),
    737                             isVolatile, isNonTemporal, Alignment);
    738       }
    739 
    740       if (TLI.isTypeLegal(MVT::i32) && !ST->isVolatile()) {
    741         // Otherwise, if the target supports 32-bit registers, use 2 32-bit
    742         // stores.  If the target supports neither 32- nor 64-bits, this
    743         // xform is certainly not worth it.
    744         const APInt &IntVal =CFP->getValueAPF().bitcastToAPInt();
    745         SDValue Lo = DAG.getConstant(IntVal.trunc(32), MVT::i32);
    746         SDValue Hi = DAG.getConstant(IntVal.lshr(32).trunc(32), MVT::i32);
    747         if (TLI.isBigEndian()) std::swap(Lo, Hi);
    748 
    749         Lo = DAG.getStore(Tmp1, dl, Lo, Tmp2, ST->getPointerInfo(), isVolatile,
    750                           isNonTemporal, Alignment);
    751         Tmp2 = DAG.getNode(ISD::ADD, dl, Tmp2.getValueType(), Tmp2,
    752                             DAG.getIntPtrConstant(4));
    753         Hi = DAG.getStore(Tmp1, dl, Hi, Tmp2,
    754                           ST->getPointerInfo().getWithOffset(4),
    755                           isVolatile, isNonTemporal, MinAlign(Alignment, 4U));
    756 
    757         return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo, Hi);
    758       }
    759     }
    760   }
    761   return SDValue(0, 0);
    762 }
    763 
    764 /// LegalizeOp - Return a legal replacement for the given operation, with
    765 /// all legal operands.
    766 SDValue SelectionDAGLegalize::LegalizeOp(SDValue Op) {
    767   if (Op.getOpcode() == ISD::TargetConstant) // Allow illegal target nodes.
    768     return Op;
    769 
    770   SDNode *Node = Op.getNode();
    771   DebugLoc dl = Node->getDebugLoc();
    772 
    773   for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i)
    774     assert(TLI.getTypeAction(*DAG.getContext(), Node->getValueType(i)) ==
    775              TargetLowering::TypeLegal &&
    776            "Unexpected illegal type!");
    777 
    778   for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i)
    779     assert((TLI.getTypeAction(*DAG.getContext(),
    780                               Node->getOperand(i).getValueType()) ==
    781               TargetLowering::TypeLegal ||
    782             Node->getOperand(i).getOpcode() == ISD::TargetConstant) &&
    783            "Unexpected illegal type!");
    784 
    785   // Note that LegalizeOp may be reentered even from single-use nodes, which
    786   // means that we always must cache transformed nodes.
    787   DenseMap<SDValue, SDValue>::iterator I = LegalizedNodes.find(Op);
    788   if (I != LegalizedNodes.end()) return I->second;
    789 
    790   SDValue Tmp1, Tmp2, Tmp3, Tmp4;
    791   SDValue Result = Op;
    792   bool isCustom = false;
    793 
    794   // Figure out the correct action; the way to query this varies by opcode
    795   TargetLowering::LegalizeAction Action = TargetLowering::Legal;
    796   bool SimpleFinishLegalizing = true;
    797   switch (Node->getOpcode()) {
    798   case ISD::INTRINSIC_W_CHAIN:
    799   case ISD::INTRINSIC_WO_CHAIN:
    800   case ISD::INTRINSIC_VOID:
    801   case ISD::VAARG:
    802   case ISD::STACKSAVE:
    803     Action = TLI.getOperationAction(Node->getOpcode(), MVT::Other);
    804     break;
    805   case ISD::SINT_TO_FP:
    806   case ISD::UINT_TO_FP:
    807   case ISD::EXTRACT_VECTOR_ELT:
    808     Action = TLI.getOperationAction(Node->getOpcode(),
    809                                     Node->getOperand(0).getValueType());
    810     break;
    811   case ISD::FP_ROUND_INREG:
    812   case ISD::SIGN_EXTEND_INREG: {
    813     EVT InnerType = cast<VTSDNode>(Node->getOperand(1))->getVT();
    814     Action = TLI.getOperationAction(Node->getOpcode(), InnerType);
    815     break;
    816   }
    817   case ISD::ATOMIC_STORE: {
    818     Action = TLI.getOperationAction(Node->getOpcode(),
    819                                     Node->getOperand(2).getValueType());
    820     break;
    821   }
    822   case ISD::SELECT_CC:
    823   case ISD::SETCC:
    824   case ISD::BR_CC: {
    825     unsigned CCOperand = Node->getOpcode() == ISD::SELECT_CC ? 4 :
    826                          Node->getOpcode() == ISD::SETCC ? 2 : 1;
    827     unsigned CompareOperand = Node->getOpcode() == ISD::BR_CC ? 2 : 0;
    828     EVT OpVT = Node->getOperand(CompareOperand).getValueType();
    829     ISD::CondCode CCCode =
    830         cast<CondCodeSDNode>(Node->getOperand(CCOperand))->get();
    831     Action = TLI.getCondCodeAction(CCCode, OpVT);
    832     if (Action == TargetLowering::Legal) {
    833       if (Node->getOpcode() == ISD::SELECT_CC)
    834         Action = TLI.getOperationAction(Node->getOpcode(),
    835                                         Node->getValueType(0));
    836       else
    837         Action = TLI.getOperationAction(Node->getOpcode(), OpVT);
    838     }
    839     break;
    840   }
    841   case ISD::LOAD:
    842   case ISD::STORE:
    843     // FIXME: Model these properly.  LOAD and STORE are complicated, and
    844     // STORE expects the unlegalized operand in some cases.
    845     SimpleFinishLegalizing = false;
    846     break;
    847   case ISD::CALLSEQ_START:
    848   case ISD::CALLSEQ_END:
    849     // FIXME: This shouldn't be necessary.  These nodes have special properties
    850     // dealing with the recursive nature of legalization.  Removing this
    851     // special case should be done as part of making LegalizeDAG non-recursive.
    852     SimpleFinishLegalizing = false;
    853     break;
    854   case ISD::EXTRACT_ELEMENT:
    855   case ISD::FLT_ROUNDS_:
    856   case ISD::SADDO:
    857   case ISD::SSUBO:
    858   case ISD::UADDO:
    859   case ISD::USUBO:
    860   case ISD::SMULO:
    861   case ISD::UMULO:
    862   case ISD::FPOWI:
    863   case ISD::MERGE_VALUES:
    864   case ISD::EH_RETURN:
    865   case ISD::FRAME_TO_ARGS_OFFSET:
    866   case ISD::EH_SJLJ_SETJMP:
    867   case ISD::EH_SJLJ_LONGJMP:
    868   case ISD::EH_SJLJ_DISPATCHSETUP:
    869     // These operations lie about being legal: when they claim to be legal,
    870     // they should actually be expanded.
    871     Action = TLI.getOperationAction(Node->getOpcode(), Node->getValueType(0));
    872     if (Action == TargetLowering::Legal)
    873       Action = TargetLowering::Expand;
    874     break;
    875   case ISD::INIT_TRAMPOLINE:
    876   case ISD::ADJUST_TRAMPOLINE:
    877   case ISD::FRAMEADDR:
    878   case ISD::RETURNADDR:
    879     // These operations lie about being legal: when they claim to be legal,
    880     // they should actually be custom-lowered.
    881     Action = TLI.getOperationAction(Node->getOpcode(), Node->getValueType(0));
    882     if (Action == TargetLowering::Legal)
    883       Action = TargetLowering::Custom;
    884     break;
    885   case ISD::BUILD_VECTOR:
    886     // A weird case: legalization for BUILD_VECTOR never legalizes the
    887     // operands!
    888     // FIXME: This really sucks... changing it isn't semantically incorrect,
    889     // but it massively pessimizes the code for floating-point BUILD_VECTORs
    890     // because ConstantFP operands get legalized into constant pool loads
    891     // before the BUILD_VECTOR code can see them.  It doesn't usually bite,
    892     // though, because BUILD_VECTORS usually get lowered into other nodes
    893     // which get legalized properly.
    894     SimpleFinishLegalizing = false;
    895     break;
    896   default:
    897     if (Node->getOpcode() >= ISD::BUILTIN_OP_END) {
    898       Action = TargetLowering::Legal;
    899     } else {
    900       Action = TLI.getOperationAction(Node->getOpcode(), Node->getValueType(0));
    901     }
    902     break;
    903   }
    904 
    905   if (SimpleFinishLegalizing) {
    906     SmallVector<SDValue, 8> Ops, ResultVals;
    907     for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i)
    908       Ops.push_back(LegalizeOp(Node->getOperand(i)));
    909     switch (Node->getOpcode()) {
    910     default: break;
    911     case ISD::BR:
    912     case ISD::BRIND:
    913     case ISD::BR_JT:
    914     case ISD::BR_CC:
    915     case ISD::BRCOND:
    916       // Branches tweak the chain to include LastCALLSEQ_END
    917       Ops[0] = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Ops[0],
    918                            LastCALLSEQ_END);
    919       Ops[0] = LegalizeOp(Ops[0]);
    920       LastCALLSEQ_END = DAG.getEntryNode();
    921       break;
    922     case ISD::SHL:
    923     case ISD::SRL:
    924     case ISD::SRA:
    925     case ISD::ROTL:
    926     case ISD::ROTR:
    927       // Legalizing shifts/rotates requires adjusting the shift amount
    928       // to the appropriate width.
    929       if (!Ops[1].getValueType().isVector())
    930         Ops[1] = LegalizeOp(DAG.getShiftAmountOperand(Ops[0].getValueType(),
    931                                                       Ops[1]));
    932       break;
    933     case ISD::SRL_PARTS:
    934     case ISD::SRA_PARTS:
    935     case ISD::SHL_PARTS:
    936       // Legalizing shifts/rotates requires adjusting the shift amount
    937       // to the appropriate width.
    938       if (!Ops[2].getValueType().isVector())
    939         Ops[2] = LegalizeOp(DAG.getShiftAmountOperand(Ops[0].getValueType(),
    940                                                       Ops[2]));
    941       break;
    942     }
    943 
    944     Result = SDValue(DAG.UpdateNodeOperands(Result.getNode(), Ops.data(),
    945                                             Ops.size()), 0);
    946     switch (Action) {
    947     case TargetLowering::Legal:
    948       for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i)
    949         ResultVals.push_back(Result.getValue(i));
    950       break;
    951     case TargetLowering::Custom:
    952       // FIXME: The handling for custom lowering with multiple results is
    953       // a complete mess.
    954       Tmp1 = TLI.LowerOperation(Result, DAG);
    955       if (Tmp1.getNode()) {
    956         for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i) {
    957           if (e == 1)
    958             ResultVals.push_back(Tmp1);
    959           else
    960             ResultVals.push_back(Tmp1.getValue(i));
    961         }
    962         break;
    963       }
    964 
    965       // FALL THROUGH
    966     case TargetLowering::Expand:
    967       ExpandNode(Result.getNode(), ResultVals);
    968       break;
    969     case TargetLowering::Promote:
    970       PromoteNode(Result.getNode(), ResultVals);
    971       break;
    972     }
    973     if (!ResultVals.empty()) {
    974       for (unsigned i = 0, e = ResultVals.size(); i != e; ++i) {
    975         if (ResultVals[i] != SDValue(Node, i))
    976           ResultVals[i] = LegalizeOp(ResultVals[i]);
    977         AddLegalizedOperand(SDValue(Node, i), ResultVals[i]);
    978       }
    979       return ResultVals[Op.getResNo()];
    980     }
    981   }
    982 
    983   switch (Node->getOpcode()) {
    984   default:
    985 #ifndef NDEBUG
    986     dbgs() << "NODE: ";
    987     Node->dump( &DAG);
    988     dbgs() << "\n";
    989 #endif
    990     assert(0 && "Do not know how to legalize this operator!");
    991 
    992   case ISD::SRA:
    993   case ISD::SRL:
    994   case ISD::SHL: {
    995     // Scalarize vector SRA/SRL/SHL.
    996     EVT VT = Node->getValueType(0);
    997     assert(VT.isVector() && "Unable to legalize non-vector shift");
    998     assert(TLI.isTypeLegal(VT.getScalarType())&& "Element type must be legal");
    999     unsigned NumElem = VT.getVectorNumElements();
   1000 
   1001     SmallVector<SDValue, 8> Scalars;
   1002     for (unsigned Idx = 0; Idx < NumElem; Idx++) {
   1003       SDValue Ex = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl,
   1004                                VT.getScalarType(),
   1005                                Node->getOperand(0), DAG.getIntPtrConstant(Idx));
   1006       SDValue Sh = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl,
   1007                                VT.getScalarType(),
   1008                                Node->getOperand(1), DAG.getIntPtrConstant(Idx));
   1009       Scalars.push_back(DAG.getNode(Node->getOpcode(), dl,
   1010                                     VT.getScalarType(), Ex, Sh));
   1011     }
   1012     Result = DAG.getNode(ISD::BUILD_VECTOR, dl, Node->getValueType(0),
   1013                          &Scalars[0], Scalars.size());
   1014     break;
   1015   }
   1016 
   1017   case ISD::BUILD_VECTOR:
   1018     switch (TLI.getOperationAction(ISD::BUILD_VECTOR, Node->getValueType(0))) {
   1019     default: assert(0 && "This action is not supported yet!");
   1020     case TargetLowering::Custom:
   1021       Tmp3 = TLI.LowerOperation(Result, DAG);
   1022       if (Tmp3.getNode()) {
   1023         Result = Tmp3;
   1024         break;
   1025       }
   1026       // FALLTHROUGH
   1027     case TargetLowering::Expand:
   1028       Result = ExpandBUILD_VECTOR(Result.getNode());
   1029       break;
   1030     }
   1031     break;
   1032   case ISD::CALLSEQ_START: {
   1033     SDNode *CallEnd = FindCallEndFromCallStart(Node);
   1034 
   1035     // Recursively Legalize all of the inputs of the call end that do not lead
   1036     // to this call start.  This ensures that any libcalls that need be inserted
   1037     // are inserted *before* the CALLSEQ_START.
   1038     {SmallPtrSet<SDNode*, 32> NodesLeadingTo;
   1039     for (unsigned i = 0, e = CallEnd->getNumOperands(); i != e; ++i)
   1040       LegalizeAllNodesNotLeadingTo(CallEnd->getOperand(i).getNode(), Node,
   1041                                    NodesLeadingTo);
   1042     }
   1043 
   1044     // Now that we have legalized all of the inputs (which may have inserted
   1045     // libcalls), create the new CALLSEQ_START node.
   1046     Tmp1 = LegalizeOp(Node->getOperand(0));  // Legalize the chain.
   1047 
   1048     // Merge in the last call to ensure that this call starts after the last
   1049     // call ended.
   1050     if (LastCALLSEQ_END.getOpcode() != ISD::EntryToken) {
   1051       Tmp1 = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
   1052                          Tmp1, LastCALLSEQ_END);
   1053       Tmp1 = LegalizeOp(Tmp1);
   1054     }
   1055 
   1056     // Do not try to legalize the target-specific arguments (#1+).
   1057     if (Tmp1 != Node->getOperand(0)) {
   1058       SmallVector<SDValue, 8> Ops(Node->op_begin(), Node->op_end());
   1059       Ops[0] = Tmp1;
   1060       Result = SDValue(DAG.UpdateNodeOperands(Result.getNode(), &Ops[0],
   1061                                               Ops.size()), Result.getResNo());
   1062     }
   1063 
   1064     // Remember that the CALLSEQ_START is legalized.
   1065     AddLegalizedOperand(Op.getValue(0), Result);
   1066     if (Node->getNumValues() == 2)    // If this has a flag result, remember it.
   1067       AddLegalizedOperand(Op.getValue(1), Result.getValue(1));
   1068 
   1069     // Now that the callseq_start and all of the non-call nodes above this call
   1070     // sequence have been legalized, legalize the call itself.  During this
   1071     // process, no libcalls can/will be inserted, guaranteeing that no calls
   1072     // can overlap.
   1073     assert(!IsLegalizingCall && "Inconsistent sequentialization of calls!");
   1074     // Note that we are selecting this call!
   1075     LastCALLSEQ_END = SDValue(CallEnd, 0);
   1076     IsLegalizingCall = true;
   1077 
   1078     // Legalize the call, starting from the CALLSEQ_END.
   1079     LegalizeOp(LastCALLSEQ_END);
   1080     assert(!IsLegalizingCall && "CALLSEQ_END should have cleared this!");
   1081     return Result;
   1082   }
   1083   case ISD::CALLSEQ_END:
   1084     // If the CALLSEQ_START node hasn't been legalized first, legalize it.  This
   1085     // will cause this node to be legalized as well as handling libcalls right.
   1086     if (LastCALLSEQ_END.getNode() != Node) {
   1087       LegalizeOp(SDValue(FindCallStartFromCallEnd(Node), 0));
   1088       DenseMap<SDValue, SDValue>::iterator I = LegalizedNodes.find(Op);
   1089       assert(I != LegalizedNodes.end() &&
   1090              "Legalizing the call start should have legalized this node!");
   1091       return I->second;
   1092     }
   1093 
   1094     // Otherwise, the call start has been legalized and everything is going
   1095     // according to plan.  Just legalize ourselves normally here.
   1096     Tmp1 = LegalizeOp(Node->getOperand(0));  // Legalize the chain.
   1097     // Do not try to legalize the target-specific arguments (#1+), except for
   1098     // an optional flag input.
   1099     if (Node->getOperand(Node->getNumOperands()-1).getValueType() != MVT::Glue){
   1100       if (Tmp1 != Node->getOperand(0)) {
   1101         SmallVector<SDValue, 8> Ops(Node->op_begin(), Node->op_end());
   1102         Ops[0] = Tmp1;
   1103         Result = SDValue(DAG.UpdateNodeOperands(Result.getNode(),
   1104                                                 &Ops[0], Ops.size()),
   1105                          Result.getResNo());
   1106       }
   1107     } else {
   1108       Tmp2 = LegalizeOp(Node->getOperand(Node->getNumOperands()-1));
   1109       if (Tmp1 != Node->getOperand(0) ||
   1110           Tmp2 != Node->getOperand(Node->getNumOperands()-1)) {
   1111         SmallVector<SDValue, 8> Ops(Node->op_begin(), Node->op_end());
   1112         Ops[0] = Tmp1;
   1113         Ops.back() = Tmp2;
   1114         Result = SDValue(DAG.UpdateNodeOperands(Result.getNode(),
   1115                                                 &Ops[0], Ops.size()),
   1116                          Result.getResNo());
   1117       }
   1118     }
   1119     assert(IsLegalizingCall && "Call sequence imbalance between start/end?");
   1120     // This finishes up call legalization.
   1121     IsLegalizingCall = false;
   1122 
   1123     // If the CALLSEQ_END node has a flag, remember that we legalized it.
   1124     AddLegalizedOperand(SDValue(Node, 0), Result.getValue(0));
   1125     if (Node->getNumValues() == 2)
   1126       AddLegalizedOperand(SDValue(Node, 1), Result.getValue(1));
   1127     return Result.getValue(Op.getResNo());
   1128   case ISD::LOAD: {
   1129     LoadSDNode *LD = cast<LoadSDNode>(Node);
   1130     Tmp1 = LegalizeOp(LD->getChain());   // Legalize the chain.
   1131     Tmp2 = LegalizeOp(LD->getBasePtr()); // Legalize the base pointer.
   1132 
   1133     ISD::LoadExtType ExtType = LD->getExtensionType();
   1134     if (ExtType == ISD::NON_EXTLOAD) {
   1135       EVT VT = Node->getValueType(0);
   1136       Result = SDValue(DAG.UpdateNodeOperands(Result.getNode(),
   1137                                               Tmp1, Tmp2, LD->getOffset()),
   1138                        Result.getResNo());
   1139       Tmp3 = Result.getValue(0);
   1140       Tmp4 = Result.getValue(1);
   1141 
   1142       switch (TLI.getOperationAction(Node->getOpcode(), VT)) {
   1143       default: assert(0 && "This action is not supported yet!");
   1144       case TargetLowering::Legal:
   1145         // If this is an unaligned load and the target doesn't support it,
   1146         // expand it.
   1147         if (!TLI.allowsUnalignedMemoryAccesses(LD->getMemoryVT())) {
   1148           Type *Ty = LD->getMemoryVT().getTypeForEVT(*DAG.getContext());
   1149           unsigned ABIAlignment = TLI.getTargetData()->getABITypeAlignment(Ty);
   1150           if (LD->getAlignment() < ABIAlignment){
   1151             Result = ExpandUnalignedLoad(cast<LoadSDNode>(Result.getNode()),
   1152                                          DAG, TLI);
   1153             Tmp3 = Result.getOperand(0);
   1154             Tmp4 = Result.getOperand(1);
   1155             Tmp3 = LegalizeOp(Tmp3);
   1156             Tmp4 = LegalizeOp(Tmp4);
   1157           }
   1158         }
   1159         break;
   1160       case TargetLowering::Custom:
   1161         Tmp1 = TLI.LowerOperation(Tmp3, DAG);
   1162         if (Tmp1.getNode()) {
   1163           Tmp3 = LegalizeOp(Tmp1);
   1164           Tmp4 = LegalizeOp(Tmp1.getValue(1));
   1165         }
   1166         break;
   1167       case TargetLowering::Promote: {
   1168         // Only promote a load of vector type to another.
   1169         assert(VT.isVector() && "Cannot promote this load!");
   1170         // Change base type to a different vector type.
   1171         EVT NVT = TLI.getTypeToPromoteTo(Node->getOpcode(), VT);
   1172 
   1173         Tmp1 = DAG.getLoad(NVT, dl, Tmp1, Tmp2, LD->getPointerInfo(),
   1174                            LD->isVolatile(), LD->isNonTemporal(),
   1175                            LD->getAlignment());
   1176         Tmp3 = LegalizeOp(DAG.getNode(ISD::BITCAST, dl, VT, Tmp1));
   1177         Tmp4 = LegalizeOp(Tmp1.getValue(1));
   1178         break;
   1179       }
   1180       }
   1181       // Since loads produce two values, make sure to remember that we
   1182       // legalized both of them.
   1183       AddLegalizedOperand(SDValue(Node, 0), Tmp3);
   1184       AddLegalizedOperand(SDValue(Node, 1), Tmp4);
   1185       return Op.getResNo() ? Tmp4 : Tmp3;
   1186     }
   1187 
   1188     EVT SrcVT = LD->getMemoryVT();
   1189     unsigned SrcWidth = SrcVT.getSizeInBits();
   1190     unsigned Alignment = LD->getAlignment();
   1191     bool isVolatile = LD->isVolatile();
   1192     bool isNonTemporal = LD->isNonTemporal();
   1193 
   1194     if (SrcWidth != SrcVT.getStoreSizeInBits() &&
   1195         // Some targets pretend to have an i1 loading operation, and actually
   1196         // load an i8.  This trick is correct for ZEXTLOAD because the top 7
   1197         // bits are guaranteed to be zero; it helps the optimizers understand
   1198         // that these bits are zero.  It is also useful for EXTLOAD, since it
   1199         // tells the optimizers that those bits are undefined.  It would be
   1200         // nice to have an effective generic way of getting these benefits...
   1201         // Until such a way is found, don't insist on promoting i1 here.
   1202         (SrcVT != MVT::i1 ||
   1203          TLI.getLoadExtAction(ExtType, MVT::i1) == TargetLowering::Promote)) {
   1204       // Promote to a byte-sized load if not loading an integral number of
   1205       // bytes.  For example, promote EXTLOAD:i20 -> EXTLOAD:i24.
   1206       unsigned NewWidth = SrcVT.getStoreSizeInBits();
   1207       EVT NVT = EVT::getIntegerVT(*DAG.getContext(), NewWidth);
   1208       SDValue Ch;
   1209 
   1210       // The extra bits are guaranteed to be zero, since we stored them that
   1211       // way.  A zext load from NVT thus automatically gives zext from SrcVT.
   1212 
   1213       ISD::LoadExtType NewExtType =
   1214         ExtType == ISD::ZEXTLOAD ? ISD::ZEXTLOAD : ISD::EXTLOAD;
   1215 
   1216       Result = DAG.getExtLoad(NewExtType, dl, Node->getValueType(0),
   1217                               Tmp1, Tmp2, LD->getPointerInfo(),
   1218                               NVT, isVolatile, isNonTemporal, Alignment);
   1219 
   1220       Ch = Result.getValue(1); // The chain.
   1221 
   1222       if (ExtType == ISD::SEXTLOAD)
   1223         // Having the top bits zero doesn't help when sign extending.
   1224         Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, dl,
   1225                              Result.getValueType(),
   1226                              Result, DAG.getValueType(SrcVT));
   1227       else if (ExtType == ISD::ZEXTLOAD || NVT == Result.getValueType())
   1228         // All the top bits are guaranteed to be zero - inform the optimizers.
   1229         Result = DAG.getNode(ISD::AssertZext, dl,
   1230                              Result.getValueType(), Result,
   1231                              DAG.getValueType(SrcVT));
   1232 
   1233       Tmp1 = LegalizeOp(Result);
   1234       Tmp2 = LegalizeOp(Ch);
   1235     } else if (SrcWidth & (SrcWidth - 1)) {
   1236       // If not loading a power-of-2 number of bits, expand as two loads.
   1237       assert(!SrcVT.isVector() && "Unsupported extload!");
   1238       unsigned RoundWidth = 1 << Log2_32(SrcWidth);
   1239       assert(RoundWidth < SrcWidth);
   1240       unsigned ExtraWidth = SrcWidth - RoundWidth;
   1241       assert(ExtraWidth < RoundWidth);
   1242       assert(!(RoundWidth % 8) && !(ExtraWidth % 8) &&
   1243              "Load size not an integral number of bytes!");
   1244       EVT RoundVT = EVT::getIntegerVT(*DAG.getContext(), RoundWidth);
   1245       EVT ExtraVT = EVT::getIntegerVT(*DAG.getContext(), ExtraWidth);
   1246       SDValue Lo, Hi, Ch;
   1247       unsigned IncrementSize;
   1248 
   1249       if (TLI.isLittleEndian()) {
   1250         // EXTLOAD:i24 -> ZEXTLOAD:i16 | (shl EXTLOAD@+2:i8, 16)
   1251         // Load the bottom RoundWidth bits.
   1252         Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, Node->getValueType(0),
   1253                             Tmp1, Tmp2,
   1254                             LD->getPointerInfo(), RoundVT, isVolatile,
   1255                             isNonTemporal, Alignment);
   1256 
   1257         // Load the remaining ExtraWidth bits.
   1258         IncrementSize = RoundWidth / 8;
   1259         Tmp2 = DAG.getNode(ISD::ADD, dl, Tmp2.getValueType(), Tmp2,
   1260                            DAG.getIntPtrConstant(IncrementSize));
   1261         Hi = DAG.getExtLoad(ExtType, dl, Node->getValueType(0), Tmp1, Tmp2,
   1262                             LD->getPointerInfo().getWithOffset(IncrementSize),
   1263                             ExtraVT, isVolatile, isNonTemporal,
   1264                             MinAlign(Alignment, IncrementSize));
   1265 
   1266         // Build a factor node to remember that this load is independent of
   1267         // the other one.
   1268         Ch = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
   1269                          Hi.getValue(1));
   1270 
   1271         // Move the top bits to the right place.
   1272         Hi = DAG.getNode(ISD::SHL, dl, Hi.getValueType(), Hi,
   1273                          DAG.getConstant(RoundWidth,
   1274                                       TLI.getShiftAmountTy(Hi.getValueType())));
   1275 
   1276         // Join the hi and lo parts.
   1277         Result = DAG.getNode(ISD::OR, dl, Node->getValueType(0), Lo, Hi);
   1278       } else {
   1279         // Big endian - avoid unaligned loads.
   1280         // EXTLOAD:i24 -> (shl EXTLOAD:i16, 8) | ZEXTLOAD@+2:i8
   1281         // Load the top RoundWidth bits.
   1282         Hi = DAG.getExtLoad(ExtType, dl, Node->getValueType(0), Tmp1, Tmp2,
   1283                             LD->getPointerInfo(), RoundVT, isVolatile,
   1284                             isNonTemporal, Alignment);
   1285 
   1286         // Load the remaining ExtraWidth bits.
   1287         IncrementSize = RoundWidth / 8;
   1288         Tmp2 = DAG.getNode(ISD::ADD, dl, Tmp2.getValueType(), Tmp2,
   1289                            DAG.getIntPtrConstant(IncrementSize));
   1290         Lo = DAG.getExtLoad(ISD::ZEXTLOAD,
   1291                             dl, Node->getValueType(0), Tmp1, Tmp2,
   1292                             LD->getPointerInfo().getWithOffset(IncrementSize),
   1293                             ExtraVT, isVolatile, isNonTemporal,
   1294                             MinAlign(Alignment, IncrementSize));
   1295 
   1296         // Build a factor node to remember that this load is independent of
   1297         // the other one.
   1298         Ch = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
   1299                          Hi.getValue(1));
   1300 
   1301         // Move the top bits to the right place.
   1302         Hi = DAG.getNode(ISD::SHL, dl, Hi.getValueType(), Hi,
   1303                          DAG.getConstant(ExtraWidth,
   1304                                       TLI.getShiftAmountTy(Hi.getValueType())));
   1305 
   1306         // Join the hi and lo parts.
   1307         Result = DAG.getNode(ISD::OR, dl, Node->getValueType(0), Lo, Hi);
   1308       }
   1309 
   1310       Tmp1 = LegalizeOp(Result);
   1311       Tmp2 = LegalizeOp(Ch);
   1312     } else {
   1313       switch (TLI.getLoadExtAction(ExtType, SrcVT)) {
   1314       default: assert(0 && "This action is not supported yet!");
   1315       case TargetLowering::Custom:
   1316         isCustom = true;
   1317         // FALLTHROUGH
   1318       case TargetLowering::Legal:
   1319         Result = SDValue(DAG.UpdateNodeOperands(Result.getNode(),
   1320                                                 Tmp1, Tmp2, LD->getOffset()),
   1321                          Result.getResNo());
   1322         Tmp1 = Result.getValue(0);
   1323         Tmp2 = Result.getValue(1);
   1324 
   1325         if (isCustom) {
   1326           Tmp3 = TLI.LowerOperation(Result, DAG);
   1327           if (Tmp3.getNode()) {
   1328             Tmp1 = LegalizeOp(Tmp3);
   1329             Tmp2 = LegalizeOp(Tmp3.getValue(1));
   1330           }
   1331         } else {
   1332           // If this is an unaligned load and the target doesn't support it,
   1333           // expand it.
   1334           if (!TLI.allowsUnalignedMemoryAccesses(LD->getMemoryVT())) {
   1335             Type *Ty =
   1336               LD->getMemoryVT().getTypeForEVT(*DAG.getContext());
   1337             unsigned ABIAlignment =
   1338               TLI.getTargetData()->getABITypeAlignment(Ty);
   1339             if (LD->getAlignment() < ABIAlignment){
   1340               Result = ExpandUnalignedLoad(cast<LoadSDNode>(Result.getNode()),
   1341                                            DAG, TLI);
   1342               Tmp1 = Result.getOperand(0);
   1343               Tmp2 = Result.getOperand(1);
   1344               Tmp1 = LegalizeOp(Tmp1);
   1345               Tmp2 = LegalizeOp(Tmp2);
   1346             }
   1347           }
   1348         }
   1349         break;
   1350       case TargetLowering::Expand:
   1351         if (!TLI.isLoadExtLegal(ISD::EXTLOAD, SrcVT) && TLI.isTypeLegal(SrcVT)) {
   1352           SDValue Load = DAG.getLoad(SrcVT, dl, Tmp1, Tmp2,
   1353                                      LD->getPointerInfo(),
   1354                                      LD->isVolatile(), LD->isNonTemporal(),
   1355                                      LD->getAlignment());
   1356           unsigned ExtendOp;
   1357           switch (ExtType) {
   1358           case ISD::EXTLOAD:
   1359             ExtendOp = (SrcVT.isFloatingPoint() ?
   1360                         ISD::FP_EXTEND : ISD::ANY_EXTEND);
   1361             break;
   1362           case ISD::SEXTLOAD: ExtendOp = ISD::SIGN_EXTEND; break;
   1363           case ISD::ZEXTLOAD: ExtendOp = ISD::ZERO_EXTEND; break;
   1364           default: llvm_unreachable("Unexpected extend load type!");
   1365           }
   1366           Result = DAG.getNode(ExtendOp, dl, Node->getValueType(0), Load);
   1367           Tmp1 = LegalizeOp(Result);  // Relegalize new nodes.
   1368           Tmp2 = LegalizeOp(Load.getValue(1));
   1369           break;
   1370         }
   1371 
   1372         assert(!SrcVT.isVector() &&
   1373                "Vector Loads are handled in LegalizeVectorOps");
   1374 
   1375         // FIXME: This does not work for vectors on most targets.  Sign- and
   1376         // zero-extend operations are currently folded into extending loads,
   1377         // whether they are legal or not, and then we end up here without any
   1378         // support for legalizing them.
   1379         assert(ExtType != ISD::EXTLOAD &&
   1380                "EXTLOAD should always be supported!");
   1381         // Turn the unsupported load into an EXTLOAD followed by an explicit
   1382         // zero/sign extend inreg.
   1383         Result = DAG.getExtLoad(ISD::EXTLOAD, dl, Node->getValueType(0),
   1384                                 Tmp1, Tmp2, LD->getPointerInfo(), SrcVT,
   1385                                 LD->isVolatile(), LD->isNonTemporal(),
   1386                                 LD->getAlignment());
   1387         SDValue ValRes;
   1388         if (ExtType == ISD::SEXTLOAD)
   1389           ValRes = DAG.getNode(ISD::SIGN_EXTEND_INREG, dl,
   1390                                Result.getValueType(),
   1391                                Result, DAG.getValueType(SrcVT));
   1392         else
   1393           ValRes = DAG.getZeroExtendInReg(Result, dl, SrcVT.getScalarType());
   1394         Tmp1 = LegalizeOp(ValRes);  // Relegalize new nodes.
   1395         Tmp2 = LegalizeOp(Result.getValue(1));  // Relegalize new nodes.
   1396         break;
   1397       }
   1398     }
   1399 
   1400     // Since loads produce two values, make sure to remember that we legalized
   1401     // both of them.
   1402     AddLegalizedOperand(SDValue(Node, 0), Tmp1);
   1403     AddLegalizedOperand(SDValue(Node, 1), Tmp2);
   1404     return Op.getResNo() ? Tmp2 : Tmp1;
   1405   }
   1406   case ISD::STORE: {
   1407     StoreSDNode *ST = cast<StoreSDNode>(Node);
   1408     Tmp1 = LegalizeOp(ST->getChain());    // Legalize the chain.
   1409     Tmp2 = LegalizeOp(ST->getBasePtr());  // Legalize the pointer.
   1410     unsigned Alignment = ST->getAlignment();
   1411     bool isVolatile = ST->isVolatile();
   1412     bool isNonTemporal = ST->isNonTemporal();
   1413 
   1414     if (!ST->isTruncatingStore()) {
   1415       if (SDNode *OptStore = OptimizeFloatStore(ST).getNode()) {
   1416         Result = SDValue(OptStore, 0);
   1417         break;
   1418       }
   1419 
   1420       {
   1421         Tmp3 = LegalizeOp(ST->getValue());
   1422         Result = SDValue(DAG.UpdateNodeOperands(Result.getNode(),
   1423                                                 Tmp1, Tmp3, Tmp2,
   1424                                                 ST->getOffset()),
   1425                          Result.getResNo());
   1426 
   1427         EVT VT = Tmp3.getValueType();
   1428         switch (TLI.getOperationAction(ISD::STORE, VT)) {
   1429         default: assert(0 && "This action is not supported yet!");
   1430         case TargetLowering::Legal:
   1431           // If this is an unaligned store and the target doesn't support it,
   1432           // expand it.
   1433           if (!TLI.allowsUnalignedMemoryAccesses(ST->getMemoryVT())) {
   1434             Type *Ty = ST->getMemoryVT().getTypeForEVT(*DAG.getContext());
   1435             unsigned ABIAlignment= TLI.getTargetData()->getABITypeAlignment(Ty);
   1436             if (ST->getAlignment() < ABIAlignment)
   1437               Result = ExpandUnalignedStore(cast<StoreSDNode>(Result.getNode()),
   1438                                             DAG, TLI);
   1439           }
   1440           break;
   1441         case TargetLowering::Custom:
   1442           Tmp1 = TLI.LowerOperation(Result, DAG);
   1443           if (Tmp1.getNode()) Result = Tmp1;
   1444           break;
   1445         case TargetLowering::Promote:
   1446           assert(VT.isVector() && "Unknown legal promote case!");
   1447           Tmp3 = DAG.getNode(ISD::BITCAST, dl,
   1448                              TLI.getTypeToPromoteTo(ISD::STORE, VT), Tmp3);
   1449           Result = DAG.getStore(Tmp1, dl, Tmp3, Tmp2,
   1450                                 ST->getPointerInfo(), isVolatile,
   1451                                 isNonTemporal, Alignment);
   1452           break;
   1453         }
   1454         break;
   1455       }
   1456     } else {
   1457       Tmp3 = LegalizeOp(ST->getValue());
   1458 
   1459       EVT StVT = ST->getMemoryVT();
   1460       unsigned StWidth = StVT.getSizeInBits();
   1461 
   1462       if (StWidth != StVT.getStoreSizeInBits()) {
   1463         // Promote to a byte-sized store with upper bits zero if not
   1464         // storing an integral number of bytes.  For example, promote
   1465         // TRUNCSTORE:i1 X -> TRUNCSTORE:i8 (and X, 1)
   1466         EVT NVT = EVT::getIntegerVT(*DAG.getContext(),
   1467                                     StVT.getStoreSizeInBits());
   1468         Tmp3 = DAG.getZeroExtendInReg(Tmp3, dl, StVT);
   1469         Result = DAG.getTruncStore(Tmp1, dl, Tmp3, Tmp2, ST->getPointerInfo(),
   1470                                    NVT, isVolatile, isNonTemporal, Alignment);
   1471       } else if (StWidth & (StWidth - 1)) {
   1472         // If not storing a power-of-2 number of bits, expand as two stores.
   1473         assert(!StVT.isVector() && "Unsupported truncstore!");
   1474         unsigned RoundWidth = 1 << Log2_32(StWidth);
   1475         assert(RoundWidth < StWidth);
   1476         unsigned ExtraWidth = StWidth - RoundWidth;
   1477         assert(ExtraWidth < RoundWidth);
   1478         assert(!(RoundWidth % 8) && !(ExtraWidth % 8) &&
   1479                "Store size not an integral number of bytes!");
   1480         EVT RoundVT = EVT::getIntegerVT(*DAG.getContext(), RoundWidth);
   1481         EVT ExtraVT = EVT::getIntegerVT(*DAG.getContext(), ExtraWidth);
   1482         SDValue Lo, Hi;
   1483         unsigned IncrementSize;
   1484 
   1485         if (TLI.isLittleEndian()) {
   1486           // TRUNCSTORE:i24 X -> TRUNCSTORE:i16 X, TRUNCSTORE@+2:i8 (srl X, 16)
   1487           // Store the bottom RoundWidth bits.
   1488           Lo = DAG.getTruncStore(Tmp1, dl, Tmp3, Tmp2, ST->getPointerInfo(),
   1489                                  RoundVT,
   1490                                  isVolatile, isNonTemporal, Alignment);
   1491 
   1492           // Store the remaining ExtraWidth bits.
   1493           IncrementSize = RoundWidth / 8;
   1494           Tmp2 = DAG.getNode(ISD::ADD, dl, Tmp2.getValueType(), Tmp2,
   1495                              DAG.getIntPtrConstant(IncrementSize));
   1496           Hi = DAG.getNode(ISD::SRL, dl, Tmp3.getValueType(), Tmp3,
   1497                            DAG.getConstant(RoundWidth,
   1498                                     TLI.getShiftAmountTy(Tmp3.getValueType())));
   1499           Hi = DAG.getTruncStore(Tmp1, dl, Hi, Tmp2,
   1500                              ST->getPointerInfo().getWithOffset(IncrementSize),
   1501                                  ExtraVT, isVolatile, isNonTemporal,
   1502                                  MinAlign(Alignment, IncrementSize));
   1503         } else {
   1504           // Big endian - avoid unaligned stores.
   1505           // TRUNCSTORE:i24 X -> TRUNCSTORE:i16 (srl X, 8), TRUNCSTORE@+2:i8 X
   1506           // Store the top RoundWidth bits.
   1507           Hi = DAG.getNode(ISD::SRL, dl, Tmp3.getValueType(), Tmp3,
   1508                            DAG.getConstant(ExtraWidth,
   1509                                     TLI.getShiftAmountTy(Tmp3.getValueType())));
   1510           Hi = DAG.getTruncStore(Tmp1, dl, Hi, Tmp2, ST->getPointerInfo(),
   1511                                  RoundVT, isVolatile, isNonTemporal, Alignment);
   1512 
   1513           // Store the remaining ExtraWidth bits.
   1514           IncrementSize = RoundWidth / 8;
   1515           Tmp2 = DAG.getNode(ISD::ADD, dl, Tmp2.getValueType(), Tmp2,
   1516                              DAG.getIntPtrConstant(IncrementSize));
   1517           Lo = DAG.getTruncStore(Tmp1, dl, Tmp3, Tmp2,
   1518                               ST->getPointerInfo().getWithOffset(IncrementSize),
   1519                                  ExtraVT, isVolatile, isNonTemporal,
   1520                                  MinAlign(Alignment, IncrementSize));
   1521         }
   1522 
   1523         // The order of the stores doesn't matter.
   1524         Result = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo, Hi);
   1525       } else {
   1526         if (Tmp1 != ST->getChain() || Tmp3 != ST->getValue() ||
   1527             Tmp2 != ST->getBasePtr())
   1528           Result = SDValue(DAG.UpdateNodeOperands(Result.getNode(),
   1529                                                   Tmp1, Tmp3, Tmp2,
   1530                                                   ST->getOffset()),
   1531                            Result.getResNo());
   1532 
   1533         switch (TLI.getTruncStoreAction(ST->getValue().getValueType(), StVT)) {
   1534         default: assert(0 && "This action is not supported yet!");
   1535         case TargetLowering::Legal:
   1536           // If this is an unaligned store and the target doesn't support it,
   1537           // expand it.
   1538           if (!TLI.allowsUnalignedMemoryAccesses(ST->getMemoryVT())) {
   1539             Type *Ty = ST->getMemoryVT().getTypeForEVT(*DAG.getContext());
   1540             unsigned ABIAlignment= TLI.getTargetData()->getABITypeAlignment(Ty);
   1541             if (ST->getAlignment() < ABIAlignment)
   1542               Result = ExpandUnalignedStore(cast<StoreSDNode>(Result.getNode()),
   1543                                             DAG, TLI);
   1544           }
   1545           break;
   1546         case TargetLowering::Custom:
   1547           Result = TLI.LowerOperation(Result, DAG);
   1548           break;
   1549         case TargetLowering::Expand:
   1550           assert(!StVT.isVector() &&
   1551                  "Vector Stores are handled in LegalizeVectorOps");
   1552 
   1553           // TRUNCSTORE:i16 i32 -> STORE i16
   1554           assert(TLI.isTypeLegal(StVT) && "Do not know how to expand this store!");
   1555           Tmp3 = DAG.getNode(ISD::TRUNCATE, dl, StVT, Tmp3);
   1556           Result = DAG.getStore(Tmp1, dl, Tmp3, Tmp2, ST->getPointerInfo(),
   1557                                 isVolatile, isNonTemporal, Alignment);
   1558           break;
   1559         }
   1560       }
   1561     }
   1562     break;
   1563   }
   1564   }
   1565   assert(Result.getValueType() == Op.getValueType() &&
   1566          "Bad legalization!");
   1567 
   1568   // Make sure that the generated code is itself legal.
   1569   if (Result != Op)
   1570     Result = LegalizeOp(Result);
   1571 
   1572   // Note that LegalizeOp may be reentered even from single-use nodes, which
   1573   // means that we always must cache transformed nodes.
   1574   AddLegalizedOperand(Op, Result);
   1575   return Result;
   1576 }
   1577 
   1578 SDValue SelectionDAGLegalize::ExpandExtractFromVectorThroughStack(SDValue Op) {
   1579   SDValue Vec = Op.getOperand(0);
   1580   SDValue Idx = Op.getOperand(1);
   1581   DebugLoc dl = Op.getDebugLoc();
   1582   // Store the value to a temporary stack slot, then LOAD the returned part.
   1583   SDValue StackPtr = DAG.CreateStackTemporary(Vec.getValueType());
   1584   SDValue Ch = DAG.getStore(DAG.getEntryNode(), dl, Vec, StackPtr,
   1585                             MachinePointerInfo(), false, false, 0);
   1586 
   1587   // Add the offset to the index.
   1588   unsigned EltSize =
   1589       Vec.getValueType().getVectorElementType().getSizeInBits()/8;
   1590   Idx = DAG.getNode(ISD::MUL, dl, Idx.getValueType(), Idx,
   1591                     DAG.getConstant(EltSize, Idx.getValueType()));
   1592 
   1593   if (Idx.getValueType().bitsGT(TLI.getPointerTy()))
   1594     Idx = DAG.getNode(ISD::TRUNCATE, dl, TLI.getPointerTy(), Idx);
   1595   else
   1596     Idx = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Idx);
   1597 
   1598   StackPtr = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, StackPtr);
   1599 
   1600   if (Op.getValueType().isVector())
   1601     return DAG.getLoad(Op.getValueType(), dl, Ch, StackPtr,MachinePointerInfo(),
   1602                        false, false, 0);
   1603   return DAG.getExtLoad(ISD::EXTLOAD, dl, Op.getValueType(), Ch, StackPtr,
   1604                         MachinePointerInfo(),
   1605                         Vec.getValueType().getVectorElementType(),
   1606                         false, false, 0);
   1607 }
   1608 
   1609 SDValue SelectionDAGLegalize::ExpandInsertToVectorThroughStack(SDValue Op) {
   1610   assert(Op.getValueType().isVector() && "Non-vector insert subvector!");
   1611 
   1612   SDValue Vec  = Op.getOperand(0);
   1613   SDValue Part = Op.getOperand(1);
   1614   SDValue Idx  = Op.getOperand(2);
   1615   DebugLoc dl  = Op.getDebugLoc();
   1616 
   1617   // Store the value to a temporary stack slot, then LOAD the returned part.
   1618 
   1619   SDValue StackPtr = DAG.CreateStackTemporary(Vec.getValueType());
   1620   int FI = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
   1621   MachinePointerInfo PtrInfo = MachinePointerInfo::getFixedStack(FI);
   1622 
   1623   // First store the whole vector.
   1624   SDValue Ch = DAG.getStore(DAG.getEntryNode(), dl, Vec, StackPtr, PtrInfo,
   1625                             false, false, 0);
   1626 
   1627   // Then store the inserted part.
   1628 
   1629   // Add the offset to the index.
   1630   unsigned EltSize =
   1631       Vec.getValueType().getVectorElementType().getSizeInBits()/8;
   1632 
   1633   Idx = DAG.getNode(ISD::MUL, dl, Idx.getValueType(), Idx,
   1634                     DAG.getConstant(EltSize, Idx.getValueType()));
   1635 
   1636   if (Idx.getValueType().bitsGT(TLI.getPointerTy()))
   1637     Idx = DAG.getNode(ISD::TRUNCATE, dl, TLI.getPointerTy(), Idx);
   1638   else
   1639     Idx = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Idx);
   1640 
   1641   SDValue SubStackPtr = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx,
   1642                                     StackPtr);
   1643 
   1644   // Store the subvector.
   1645   Ch = DAG.getStore(DAG.getEntryNode(), dl, Part, SubStackPtr,
   1646                     MachinePointerInfo(), false, false, 0);
   1647 
   1648   // Finally, load the updated vector.
   1649   return DAG.getLoad(Op.getValueType(), dl, Ch, StackPtr, PtrInfo,
   1650                      false, false, 0);
   1651 }
   1652 
   1653 SDValue SelectionDAGLegalize::ExpandVectorBuildThroughStack(SDNode* Node) {
   1654   // We can't handle this case efficiently.  Allocate a sufficiently
   1655   // aligned object on the stack, store each element into it, then load
   1656   // the result as a vector.
   1657   // Create the stack frame object.
   1658   EVT VT = Node->getValueType(0);
   1659   EVT EltVT = VT.getVectorElementType();
   1660   DebugLoc dl = Node->getDebugLoc();
   1661   SDValue FIPtr = DAG.CreateStackTemporary(VT);
   1662   int FI = cast<FrameIndexSDNode>(FIPtr.getNode())->getIndex();
   1663   MachinePointerInfo PtrInfo = MachinePointerInfo::getFixedStack(FI);
   1664 
   1665   // Emit a store of each element to the stack slot.
   1666   SmallVector<SDValue, 8> Stores;
   1667   unsigned TypeByteSize = EltVT.getSizeInBits() / 8;
   1668   // Store (in the right endianness) the elements to memory.
   1669   for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) {
   1670     // Ignore undef elements.
   1671     if (Node->getOperand(i).getOpcode() == ISD::UNDEF) continue;
   1672 
   1673     unsigned Offset = TypeByteSize*i;
   1674 
   1675     SDValue Idx = DAG.getConstant(Offset, FIPtr.getValueType());
   1676     Idx = DAG.getNode(ISD::ADD, dl, FIPtr.getValueType(), FIPtr, Idx);
   1677 
   1678     // If the destination vector element type is narrower than the source
   1679     // element type, only store the bits necessary.
   1680     if (EltVT.bitsLT(Node->getOperand(i).getValueType().getScalarType())) {
   1681       Stores.push_back(DAG.getTruncStore(DAG.getEntryNode(), dl,
   1682                                          Node->getOperand(i), Idx,
   1683                                          PtrInfo.getWithOffset(Offset),
   1684                                          EltVT, false, false, 0));
   1685     } else
   1686       Stores.push_back(DAG.getStore(DAG.getEntryNode(), dl,
   1687                                     Node->getOperand(i), Idx,
   1688                                     PtrInfo.getWithOffset(Offset),
   1689                                     false, false, 0));
   1690   }
   1691 
   1692   SDValue StoreChain;
   1693   if (!Stores.empty())    // Not all undef elements?
   1694     StoreChain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
   1695                              &Stores[0], Stores.size());
   1696   else
   1697     StoreChain = DAG.getEntryNode();
   1698 
   1699   // Result is a load from the stack slot.
   1700   return DAG.getLoad(VT, dl, StoreChain, FIPtr, PtrInfo, false, false, 0);
   1701 }
   1702 
   1703 SDValue SelectionDAGLegalize::ExpandFCOPYSIGN(SDNode* Node) {
   1704   DebugLoc dl = Node->getDebugLoc();
   1705   SDValue Tmp1 = Node->getOperand(0);
   1706   SDValue Tmp2 = Node->getOperand(1);
   1707 
   1708   // Get the sign bit of the RHS.  First obtain a value that has the same
   1709   // sign as the sign bit, i.e. negative if and only if the sign bit is 1.
   1710   SDValue SignBit;
   1711   EVT FloatVT = Tmp2.getValueType();
   1712   EVT IVT = EVT::getIntegerVT(*DAG.getContext(), FloatVT.getSizeInBits());
   1713   if (TLI.isTypeLegal(IVT)) {
   1714     // Convert to an integer with the same sign bit.
   1715     SignBit = DAG.getNode(ISD::BITCAST, dl, IVT, Tmp2);
   1716   } else {
   1717     // Store the float to memory, then load the sign part out as an integer.
   1718     MVT LoadTy = TLI.getPointerTy();
   1719     // First create a temporary that is aligned for both the load and store.
   1720     SDValue StackPtr = DAG.CreateStackTemporary(FloatVT, LoadTy);
   1721     // Then store the float to it.
   1722     SDValue Ch =
   1723       DAG.getStore(DAG.getEntryNode(), dl, Tmp2, StackPtr, MachinePointerInfo(),
   1724                    false, false, 0);
   1725     if (TLI.isBigEndian()) {
   1726       assert(FloatVT.isByteSized() && "Unsupported floating point type!");
   1727       // Load out a legal integer with the same sign bit as the float.
   1728       SignBit = DAG.getLoad(LoadTy, dl, Ch, StackPtr, MachinePointerInfo(),
   1729                             false, false, 0);
   1730     } else { // Little endian
   1731       SDValue LoadPtr = StackPtr;
   1732       // The float may be wider than the integer we are going to load.  Advance
   1733       // the pointer so that the loaded integer will contain the sign bit.
   1734       unsigned Strides = (FloatVT.getSizeInBits()-1)/LoadTy.getSizeInBits();
   1735       unsigned ByteOffset = (Strides * LoadTy.getSizeInBits()) / 8;
   1736       LoadPtr = DAG.getNode(ISD::ADD, dl, LoadPtr.getValueType(),
   1737                             LoadPtr, DAG.getIntPtrConstant(ByteOffset));
   1738       // Load a legal integer containing the sign bit.
   1739       SignBit = DAG.getLoad(LoadTy, dl, Ch, LoadPtr, MachinePointerInfo(),
   1740                             false, false, 0);
   1741       // Move the sign bit to the top bit of the loaded integer.
   1742       unsigned BitShift = LoadTy.getSizeInBits() -
   1743         (FloatVT.getSizeInBits() - 8 * ByteOffset);
   1744       assert(BitShift < LoadTy.getSizeInBits() && "Pointer advanced wrong?");
   1745       if (BitShift)
   1746         SignBit = DAG.getNode(ISD::SHL, dl, LoadTy, SignBit,
   1747                               DAG.getConstant(BitShift,
   1748                                  TLI.getShiftAmountTy(SignBit.getValueType())));
   1749     }
   1750   }
   1751   // Now get the sign bit proper, by seeing whether the value is negative.
   1752   SignBit = DAG.getSetCC(dl, TLI.getSetCCResultType(SignBit.getValueType()),
   1753                          SignBit, DAG.getConstant(0, SignBit.getValueType()),
   1754                          ISD::SETLT);
   1755   // Get the absolute value of the result.
   1756   SDValue AbsVal = DAG.getNode(ISD::FABS, dl, Tmp1.getValueType(), Tmp1);
   1757   // Select between the nabs and abs value based on the sign bit of
   1758   // the input.
   1759   return DAG.getNode(ISD::SELECT, dl, AbsVal.getValueType(), SignBit,
   1760                      DAG.getNode(ISD::FNEG, dl, AbsVal.getValueType(), AbsVal),
   1761                      AbsVal);
   1762 }
   1763 
   1764 void SelectionDAGLegalize::ExpandDYNAMIC_STACKALLOC(SDNode* Node,
   1765                                            SmallVectorImpl<SDValue> &Results) {
   1766   unsigned SPReg = TLI.getStackPointerRegisterToSaveRestore();
   1767   assert(SPReg && "Target cannot require DYNAMIC_STACKALLOC expansion and"
   1768           " not tell us which reg is the stack pointer!");
   1769   DebugLoc dl = Node->getDebugLoc();
   1770   EVT VT = Node->getValueType(0);
   1771   SDValue Tmp1 = SDValue(Node, 0);
   1772   SDValue Tmp2 = SDValue(Node, 1);
   1773   SDValue Tmp3 = Node->getOperand(2);
   1774   SDValue Chain = Tmp1.getOperand(0);
   1775 
   1776   // Chain the dynamic stack allocation so that it doesn't modify the stack
   1777   // pointer when other instructions are using the stack.
   1778   Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(0, true));
   1779 
   1780   SDValue Size  = Tmp2.getOperand(1);
   1781   SDValue SP = DAG.getCopyFromReg(Chain, dl, SPReg, VT);
   1782   Chain = SP.getValue(1);
   1783   unsigned Align = cast<ConstantSDNode>(Tmp3)->getZExtValue();
   1784   unsigned StackAlign = TM.getFrameLowering()->getStackAlignment();
   1785   if (Align > StackAlign)
   1786     SP = DAG.getNode(ISD::AND, dl, VT, SP,
   1787                       DAG.getConstant(-(uint64_t)Align, VT));
   1788   Tmp1 = DAG.getNode(ISD::SUB, dl, VT, SP, Size);       // Value
   1789   Chain = DAG.getCopyToReg(Chain, dl, SPReg, Tmp1);     // Output chain
   1790 
   1791   Tmp2 = DAG.getCALLSEQ_END(Chain,  DAG.getIntPtrConstant(0, true),
   1792                             DAG.getIntPtrConstant(0, true), SDValue());
   1793 
   1794   Results.push_back(Tmp1);
   1795   Results.push_back(Tmp2);
   1796 }
   1797 
   1798 /// LegalizeSetCCCondCode - Legalize a SETCC with given LHS and RHS and
   1799 /// condition code CC on the current target. This routine expands SETCC with
   1800 /// illegal condition code into AND / OR of multiple SETCC values.
   1801 void SelectionDAGLegalize::LegalizeSetCCCondCode(EVT VT,
   1802                                                  SDValue &LHS, SDValue &RHS,
   1803                                                  SDValue &CC,
   1804                                                  DebugLoc dl) {
   1805   EVT OpVT = LHS.getValueType();
   1806   ISD::CondCode CCCode = cast<CondCodeSDNode>(CC)->get();
   1807   switch (TLI.getCondCodeAction(CCCode, OpVT)) {
   1808   default: assert(0 && "Unknown condition code action!");
   1809   case TargetLowering::Legal:
   1810     // Nothing to do.
   1811     break;
   1812   case TargetLowering::Expand: {
   1813     ISD::CondCode CC1 = ISD::SETCC_INVALID, CC2 = ISD::SETCC_INVALID;
   1814     unsigned Opc = 0;
   1815     switch (CCCode) {
   1816     default: assert(0 && "Don't know how to expand this condition!");
   1817     case ISD::SETOEQ: CC1 = ISD::SETEQ; CC2 = ISD::SETO;  Opc = ISD::AND; break;
   1818     case ISD::SETOGT: CC1 = ISD::SETGT; CC2 = ISD::SETO;  Opc = ISD::AND; break;
   1819     case ISD::SETOGE: CC1 = ISD::SETGE; CC2 = ISD::SETO;  Opc = ISD::AND; break;
   1820     case ISD::SETOLT: CC1 = ISD::SETLT; CC2 = ISD::SETO;  Opc = ISD::AND; break;
   1821     case ISD::SETOLE: CC1 = ISD::SETLE; CC2 = ISD::SETO;  Opc = ISD::AND; break;
   1822     case ISD::SETONE: CC1 = ISD::SETNE; CC2 = ISD::SETO;  Opc = ISD::AND; break;
   1823     case ISD::SETUEQ: CC1 = ISD::SETEQ; CC2 = ISD::SETUO; Opc = ISD::OR;  break;
   1824     case ISD::SETUGT: CC1 = ISD::SETGT; CC2 = ISD::SETUO; Opc = ISD::OR;  break;
   1825     case ISD::SETUGE: CC1 = ISD::SETGE; CC2 = ISD::SETUO; Opc = ISD::OR;  break;
   1826     case ISD::SETULT: CC1 = ISD::SETLT; CC2 = ISD::SETUO; Opc = ISD::OR;  break;
   1827     case ISD::SETULE: CC1 = ISD::SETLE; CC2 = ISD::SETUO; Opc = ISD::OR;  break;
   1828     case ISD::SETUNE: CC1 = ISD::SETNE; CC2 = ISD::SETUO; Opc = ISD::OR;  break;
   1829     // FIXME: Implement more expansions.
   1830     }
   1831 
   1832     SDValue SetCC1 = DAG.getSetCC(dl, VT, LHS, RHS, CC1);
   1833     SDValue SetCC2 = DAG.getSetCC(dl, VT, LHS, RHS, CC2);
   1834     LHS = DAG.getNode(Opc, dl, VT, SetCC1, SetCC2);
   1835     RHS = SDValue();
   1836     CC  = SDValue();
   1837     break;
   1838   }
   1839   }
   1840 }
   1841 
   1842 /// EmitStackConvert - Emit a store/load combination to the stack.  This stores
   1843 /// SrcOp to a stack slot of type SlotVT, truncating it if needed.  It then does
   1844 /// a load from the stack slot to DestVT, extending it if needed.
   1845 /// The resultant code need not be legal.
   1846 SDValue SelectionDAGLegalize::EmitStackConvert(SDValue SrcOp,
   1847                                                EVT SlotVT,
   1848                                                EVT DestVT,
   1849                                                DebugLoc dl) {
   1850   // Create the stack frame object.
   1851   unsigned SrcAlign =
   1852     TLI.getTargetData()->getPrefTypeAlignment(SrcOp.getValueType().
   1853                                               getTypeForEVT(*DAG.getContext()));
   1854   SDValue FIPtr = DAG.CreateStackTemporary(SlotVT, SrcAlign);
   1855 
   1856   FrameIndexSDNode *StackPtrFI = cast<FrameIndexSDNode>(FIPtr);
   1857   int SPFI = StackPtrFI->getIndex();
   1858   MachinePointerInfo PtrInfo = MachinePointerInfo::getFixedStack(SPFI);
   1859 
   1860   unsigned SrcSize = SrcOp.getValueType().getSizeInBits();
   1861   unsigned SlotSize = SlotVT.getSizeInBits();
   1862   unsigned DestSize = DestVT.getSizeInBits();
   1863   Type *DestType = DestVT.getTypeForEVT(*DAG.getContext());
   1864   unsigned DestAlign = TLI.getTargetData()->getPrefTypeAlignment(DestType);
   1865 
   1866   // Emit a store to the stack slot.  Use a truncstore if the input value is
   1867   // later than DestVT.
   1868   SDValue Store;
   1869 
   1870   if (SrcSize > SlotSize)
   1871     Store = DAG.getTruncStore(DAG.getEntryNode(), dl, SrcOp, FIPtr,
   1872                               PtrInfo, SlotVT, false, false, SrcAlign);
   1873   else {
   1874     assert(SrcSize == SlotSize && "Invalid store");
   1875     Store = DAG.getStore(DAG.getEntryNode(), dl, SrcOp, FIPtr,
   1876                          PtrInfo, false, false, SrcAlign);
   1877   }
   1878 
   1879   // Result is a load from the stack slot.
   1880   if (SlotSize == DestSize)
   1881     return DAG.getLoad(DestVT, dl, Store, FIPtr, PtrInfo,
   1882                        false, false, DestAlign);
   1883 
   1884   assert(SlotSize < DestSize && "Unknown extension!");
   1885   return DAG.getExtLoad(ISD::EXTLOAD, dl, DestVT, Store, FIPtr,
   1886                         PtrInfo, SlotVT, false, false, DestAlign);
   1887 }
   1888 
   1889 SDValue SelectionDAGLegalize::ExpandSCALAR_TO_VECTOR(SDNode *Node) {
   1890   DebugLoc dl = Node->getDebugLoc();
   1891   // Create a vector sized/aligned stack slot, store the value to element #0,
   1892   // then load the whole vector back out.
   1893   SDValue StackPtr = DAG.CreateStackTemporary(Node->getValueType(0));
   1894 
   1895   FrameIndexSDNode *StackPtrFI = cast<FrameIndexSDNode>(StackPtr);
   1896   int SPFI = StackPtrFI->getIndex();
   1897 
   1898   SDValue Ch = DAG.getTruncStore(DAG.getEntryNode(), dl, Node->getOperand(0),
   1899                                  StackPtr,
   1900                                  MachinePointerInfo::getFixedStack(SPFI),
   1901                                  Node->getValueType(0).getVectorElementType(),
   1902                                  false, false, 0);
   1903   return DAG.getLoad(Node->getValueType(0), dl, Ch, StackPtr,
   1904                      MachinePointerInfo::getFixedStack(SPFI),
   1905                      false, false, 0);
   1906 }
   1907 
   1908 
   1909 /// ExpandBUILD_VECTOR - Expand a BUILD_VECTOR node on targets that don't
   1910 /// support the operation, but do support the resultant vector type.
   1911 SDValue SelectionDAGLegalize::ExpandBUILD_VECTOR(SDNode *Node) {
   1912   unsigned NumElems = Node->getNumOperands();
   1913   SDValue Value1, Value2;
   1914   DebugLoc dl = Node->getDebugLoc();
   1915   EVT VT = Node->getValueType(0);
   1916   EVT OpVT = Node->getOperand(0).getValueType();
   1917   EVT EltVT = VT.getVectorElementType();
   1918 
   1919   // If the only non-undef value is the low element, turn this into a
   1920   // SCALAR_TO_VECTOR node.  If this is { X, X, X, X }, determine X.
   1921   bool isOnlyLowElement = true;
   1922   bool MoreThanTwoValues = false;
   1923   bool isConstant = true;
   1924   for (unsigned i = 0; i < NumElems; ++i) {
   1925     SDValue V = Node->getOperand(i);
   1926     if (V.getOpcode() == ISD::UNDEF)
   1927       continue;
   1928     if (i > 0)
   1929       isOnlyLowElement = false;
   1930     if (!isa<ConstantFPSDNode>(V) && !isa<ConstantSDNode>(V))
   1931       isConstant = false;
   1932 
   1933     if (!Value1.getNode()) {
   1934       Value1 = V;
   1935     } else if (!Value2.getNode()) {
   1936       if (V != Value1)
   1937         Value2 = V;
   1938     } else if (V != Value1 && V != Value2) {
   1939       MoreThanTwoValues = true;
   1940     }
   1941   }
   1942 
   1943   if (!Value1.getNode())
   1944     return DAG.getUNDEF(VT);
   1945 
   1946   if (isOnlyLowElement)
   1947     return DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Node->getOperand(0));
   1948 
   1949   // If all elements are constants, create a load from the constant pool.
   1950   if (isConstant) {
   1951     std::vector<Constant*> CV;
   1952     for (unsigned i = 0, e = NumElems; i != e; ++i) {
   1953       if (ConstantFPSDNode *V =
   1954           dyn_cast<ConstantFPSDNode>(Node->getOperand(i))) {
   1955         CV.push_back(const_cast<ConstantFP *>(V->getConstantFPValue()));
   1956       } else if (ConstantSDNode *V =
   1957                  dyn_cast<ConstantSDNode>(Node->getOperand(i))) {
   1958         if (OpVT==EltVT)
   1959           CV.push_back(const_cast<ConstantInt *>(V->getConstantIntValue()));
   1960         else {
   1961           // If OpVT and EltVT don't match, EltVT is not legal and the
   1962           // element values have been promoted/truncated earlier.  Undo this;
   1963           // we don't want a v16i8 to become a v16i32 for example.
   1964           const ConstantInt *CI = V->getConstantIntValue();
   1965           CV.push_back(ConstantInt::get(EltVT.getTypeForEVT(*DAG.getContext()),
   1966                                         CI->getZExtValue()));
   1967         }
   1968       } else {
   1969         assert(Node->getOperand(i).getOpcode() == ISD::UNDEF);
   1970         Type *OpNTy = EltVT.getTypeForEVT(*DAG.getContext());
   1971         CV.push_back(UndefValue::get(OpNTy));
   1972       }
   1973     }
   1974     Constant *CP = ConstantVector::get(CV);
   1975     SDValue CPIdx = DAG.getConstantPool(CP, TLI.getPointerTy());
   1976     unsigned Alignment = cast<ConstantPoolSDNode>(CPIdx)->getAlignment();
   1977     return DAG.getLoad(VT, dl, DAG.getEntryNode(), CPIdx,
   1978                        MachinePointerInfo::getConstantPool(),
   1979                        false, false, Alignment);
   1980   }
   1981 
   1982   if (!MoreThanTwoValues) {
   1983     SmallVector<int, 8> ShuffleVec(NumElems, -1);
   1984     for (unsigned i = 0; i < NumElems; ++i) {
   1985       SDValue V = Node->getOperand(i);
   1986       if (V.getOpcode() == ISD::UNDEF)
   1987         continue;
   1988       ShuffleVec[i] = V == Value1 ? 0 : NumElems;
   1989     }
   1990     if (TLI.isShuffleMaskLegal(ShuffleVec, Node->getValueType(0))) {
   1991       // Get the splatted value into the low element of a vector register.
   1992       SDValue Vec1 = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Value1);
   1993       SDValue Vec2;
   1994       if (Value2.getNode())
   1995         Vec2 = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Value2);
   1996       else
   1997         Vec2 = DAG.getUNDEF(VT);
   1998 
   1999       // Return shuffle(LowValVec, undef, <0,0,0,0>)
   2000       return DAG.getVectorShuffle(VT, dl, Vec1, Vec2, ShuffleVec.data());
   2001     }
   2002   }
   2003 
   2004   // Otherwise, we can't handle this case efficiently.
   2005   return ExpandVectorBuildThroughStack(Node);
   2006 }
   2007 
   2008 // ExpandLibCall - Expand a node into a call to a libcall.  If the result value
   2009 // does not fit into a register, return the lo part and set the hi part to the
   2010 // by-reg argument.  If it does fit into a single register, return the result
   2011 // and leave the Hi part unset.
   2012 SDValue SelectionDAGLegalize::ExpandLibCall(RTLIB::Libcall LC, SDNode *Node,
   2013                                             bool isSigned) {
   2014   assert(!IsLegalizingCall && "Cannot overlap legalization of calls!");
   2015   // The input chain to this libcall is the entry node of the function.
   2016   // Legalizing the call will automatically add the previous call to the
   2017   // dependence.
   2018   SDValue InChain = DAG.getEntryNode();
   2019 
   2020   TargetLowering::ArgListTy Args;
   2021   TargetLowering::ArgListEntry Entry;
   2022   for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) {
   2023     EVT ArgVT = Node->getOperand(i).getValueType();
   2024     Type *ArgTy = ArgVT.getTypeForEVT(*DAG.getContext());
   2025     Entry.Node = Node->getOperand(i); Entry.Ty = ArgTy;
   2026     Entry.isSExt = isSigned;
   2027     Entry.isZExt = !isSigned;
   2028     Args.push_back(Entry);
   2029   }
   2030   SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC),
   2031                                          TLI.getPointerTy());
   2032 
   2033   // Splice the libcall in wherever FindInputOutputChains tells us to.
   2034   Type *RetTy = Node->getValueType(0).getTypeForEVT(*DAG.getContext());
   2035 
   2036   // isTailCall may be true since the callee does not reference caller stack
   2037   // frame. Check if it's in the right position.
   2038   bool isTailCall = isInTailCallPosition(DAG, Node, TLI);
   2039   std::pair<SDValue, SDValue> CallInfo =
   2040     TLI.LowerCallTo(InChain, RetTy, isSigned, !isSigned, false, false,
   2041                     0, TLI.getLibcallCallingConv(LC), isTailCall,
   2042                     /*isReturnValueUsed=*/true,
   2043                     Callee, Args, DAG, Node->getDebugLoc());
   2044 
   2045   if (!CallInfo.second.getNode())
   2046     // It's a tailcall, return the chain (which is the DAG root).
   2047     return DAG.getRoot();
   2048 
   2049   // Legalize the call sequence, starting with the chain.  This will advance
   2050   // the LastCALLSEQ_END to the legalized version of the CALLSEQ_END node that
   2051   // was added by LowerCallTo (guaranteeing proper serialization of calls).
   2052   LegalizeOp(CallInfo.second);
   2053   return CallInfo.first;
   2054 }
   2055 
   2056 /// ExpandLibCall - Generate a libcall taking the given operands as arguments
   2057 /// and returning a result of type RetVT.
   2058 SDValue SelectionDAGLegalize::ExpandLibCall(RTLIB::Libcall LC, EVT RetVT,
   2059                                             const SDValue *Ops, unsigned NumOps,
   2060                                             bool isSigned, DebugLoc dl) {
   2061   TargetLowering::ArgListTy Args;
   2062   Args.reserve(NumOps);
   2063 
   2064   TargetLowering::ArgListEntry Entry;
   2065   for (unsigned i = 0; i != NumOps; ++i) {
   2066     Entry.Node = Ops[i];
   2067     Entry.Ty = Entry.Node.getValueType().getTypeForEVT(*DAG.getContext());
   2068     Entry.isSExt = isSigned;
   2069     Entry.isZExt = !isSigned;
   2070     Args.push_back(Entry);
   2071   }
   2072   SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC),
   2073                                          TLI.getPointerTy());
   2074 
   2075   Type *RetTy = RetVT.getTypeForEVT(*DAG.getContext());
   2076   std::pair<SDValue,SDValue> CallInfo =
   2077   TLI.LowerCallTo(DAG.getEntryNode(), RetTy, isSigned, !isSigned, false,
   2078                   false, 0, TLI.getLibcallCallingConv(LC), false,
   2079                   /*isReturnValueUsed=*/true,
   2080                   Callee, Args, DAG, dl);
   2081 
   2082   // Legalize the call sequence, starting with the chain.  This will advance
   2083   // the LastCALLSEQ_END to the legalized version of the CALLSEQ_END node that
   2084   // was added by LowerCallTo (guaranteeing proper serialization of calls).
   2085   LegalizeOp(CallInfo.second);
   2086 
   2087   return CallInfo.first;
   2088 }
   2089 
   2090 // ExpandChainLibCall - Expand a node into a call to a libcall. Similar to
   2091 // ExpandLibCall except that the first operand is the in-chain.
   2092 std::pair<SDValue, SDValue>
   2093 SelectionDAGLegalize::ExpandChainLibCall(RTLIB::Libcall LC,
   2094                                          SDNode *Node,
   2095                                          bool isSigned) {
   2096   assert(!IsLegalizingCall && "Cannot overlap legalization of calls!");
   2097   SDValue InChain = Node->getOperand(0);
   2098 
   2099   TargetLowering::ArgListTy Args;
   2100   TargetLowering::ArgListEntry Entry;
   2101   for (unsigned i = 1, e = Node->getNumOperands(); i != e; ++i) {
   2102     EVT ArgVT = Node->getOperand(i).getValueType();
   2103     Type *ArgTy = ArgVT.getTypeForEVT(*DAG.getContext());
   2104     Entry.Node = Node->getOperand(i);
   2105     Entry.Ty = ArgTy;
   2106     Entry.isSExt = isSigned;
   2107     Entry.isZExt = !isSigned;
   2108     Args.push_back(Entry);
   2109   }
   2110   SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC),
   2111                                          TLI.getPointerTy());
   2112 
   2113   // Splice the libcall in wherever FindInputOutputChains tells us to.
   2114   Type *RetTy = Node->getValueType(0).getTypeForEVT(*DAG.getContext());
   2115   std::pair<SDValue, SDValue> CallInfo =
   2116     TLI.LowerCallTo(InChain, RetTy, isSigned, !isSigned, false, false,
   2117                     0, TLI.getLibcallCallingConv(LC), /*isTailCall=*/false,
   2118                     /*isReturnValueUsed=*/true,
   2119                     Callee, Args, DAG, Node->getDebugLoc());
   2120 
   2121   // Legalize the call sequence, starting with the chain.  This will advance
   2122   // the LastCALLSEQ_END to the legalized version of the CALLSEQ_END node that
   2123   // was added by LowerCallTo (guaranteeing proper serialization of calls).
   2124   LegalizeOp(CallInfo.second);
   2125   return CallInfo;
   2126 }
   2127 
   2128 SDValue SelectionDAGLegalize::ExpandFPLibCall(SDNode* Node,
   2129                                               RTLIB::Libcall Call_F32,
   2130                                               RTLIB::Libcall Call_F64,
   2131                                               RTLIB::Libcall Call_F80,
   2132                                               RTLIB::Libcall Call_PPCF128) {
   2133   RTLIB::Libcall LC;
   2134   switch (Node->getValueType(0).getSimpleVT().SimpleTy) {
   2135   default: assert(0 && "Unexpected request for libcall!");
   2136   case MVT::f32: LC = Call_F32; break;
   2137   case MVT::f64: LC = Call_F64; break;
   2138   case MVT::f80: LC = Call_F80; break;
   2139   case MVT::ppcf128: LC = Call_PPCF128; break;
   2140   }
   2141   return ExpandLibCall(LC, Node, false);
   2142 }
   2143 
   2144 SDValue SelectionDAGLegalize::ExpandIntLibCall(SDNode* Node, bool isSigned,
   2145                                                RTLIB::Libcall Call_I8,
   2146                                                RTLIB::Libcall Call_I16,
   2147                                                RTLIB::Libcall Call_I32,
   2148                                                RTLIB::Libcall Call_I64,
   2149                                                RTLIB::Libcall Call_I128) {
   2150   RTLIB::Libcall LC;
   2151   switch (Node->getValueType(0).getSimpleVT().SimpleTy) {
   2152   default: assert(0 && "Unexpected request for libcall!");
   2153   case MVT::i8:   LC = Call_I8; break;
   2154   case MVT::i16:  LC = Call_I16; break;
   2155   case MVT::i32:  LC = Call_I32; break;
   2156   case MVT::i64:  LC = Call_I64; break;
   2157   case MVT::i128: LC = Call_I128; break;
   2158   }
   2159   return ExpandLibCall(LC, Node, isSigned);
   2160 }
   2161 
   2162 /// isDivRemLibcallAvailable - Return true if divmod libcall is available.
   2163 static bool isDivRemLibcallAvailable(SDNode *Node, bool isSigned,
   2164                                      const TargetLowering &TLI) {
   2165   RTLIB::Libcall LC;
   2166   switch (Node->getValueType(0).getSimpleVT().SimpleTy) {
   2167   default: assert(0 && "Unexpected request for libcall!");
   2168   case MVT::i8:   LC= isSigned ? RTLIB::SDIVREM_I8  : RTLIB::UDIVREM_I8;  break;
   2169   case MVT::i16:  LC= isSigned ? RTLIB::SDIVREM_I16 : RTLIB::UDIVREM_I16; break;
   2170   case MVT::i32:  LC= isSigned ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32; break;
   2171   case MVT::i64:  LC= isSigned ? RTLIB::SDIVREM_I64 : RTLIB::UDIVREM_I64; break;
   2172   case MVT::i128: LC= isSigned ? RTLIB::SDIVREM_I128:RTLIB::UDIVREM_I128; break;
   2173   }
   2174 
   2175   return TLI.getLibcallName(LC) != 0;
   2176 }
   2177 
   2178 /// UseDivRem - Only issue divrem libcall if both quotient and remainder are
   2179 /// needed.
   2180 static bool UseDivRem(SDNode *Node, bool isSigned, bool isDIV) {
   2181   unsigned OtherOpcode = 0;
   2182   if (isSigned)
   2183     OtherOpcode = isDIV ? ISD::SREM : ISD::SDIV;
   2184   else
   2185     OtherOpcode = isDIV ? ISD::UREM : ISD::UDIV;
   2186 
   2187   SDValue Op0 = Node->getOperand(0);
   2188   SDValue Op1 = Node->getOperand(1);
   2189   for (SDNode::use_iterator UI = Op0.getNode()->use_begin(),
   2190          UE = Op0.getNode()->use_end(); UI != UE; ++UI) {
   2191     SDNode *User = *UI;
   2192     if (User == Node)
   2193       continue;
   2194     if (User->getOpcode() == OtherOpcode &&
   2195         User->getOperand(0) == Op0 &&
   2196         User->getOperand(1) == Op1)
   2197       return true;
   2198   }
   2199   return false;
   2200 }
   2201 
   2202 /// ExpandDivRemLibCall - Issue libcalls to __{u}divmod to compute div / rem
   2203 /// pairs.
   2204 void
   2205 SelectionDAGLegalize::ExpandDivRemLibCall(SDNode *Node,
   2206                                           SmallVectorImpl<SDValue> &Results) {
   2207   unsigned Opcode = Node->getOpcode();
   2208   bool isSigned = Opcode == ISD::SDIVREM;
   2209 
   2210   RTLIB::Libcall LC;
   2211   switch (Node->getValueType(0).getSimpleVT().SimpleTy) {
   2212   default: assert(0 && "Unexpected request for libcall!");
   2213   case MVT::i8:   LC= isSigned ? RTLIB::SDIVREM_I8  : RTLIB::UDIVREM_I8;  break;
   2214   case MVT::i16:  LC= isSigned ? RTLIB::SDIVREM_I16 : RTLIB::UDIVREM_I16; break;
   2215   case MVT::i32:  LC= isSigned ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32; break;
   2216   case MVT::i64:  LC= isSigned ? RTLIB::SDIVREM_I64 : RTLIB::UDIVREM_I64; break;
   2217   case MVT::i128: LC= isSigned ? RTLIB::SDIVREM_I128:RTLIB::UDIVREM_I128; break;
   2218   }
   2219 
   2220   // The input chain to this libcall is the entry node of the function.
   2221   // Legalizing the call will automatically add the previous call to the
   2222   // dependence.
   2223   SDValue InChain = DAG.getEntryNode();
   2224 
   2225   EVT RetVT = Node->getValueType(0);
   2226   Type *RetTy = RetVT.getTypeForEVT(*DAG.getContext());
   2227 
   2228   TargetLowering::ArgListTy Args;
   2229   TargetLowering::ArgListEntry Entry;
   2230   for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) {
   2231     EVT ArgVT = Node->getOperand(i).getValueType();
   2232     Type *ArgTy = ArgVT.getTypeForEVT(*DAG.getContext());
   2233     Entry.Node = Node->getOperand(i); Entry.Ty = ArgTy;
   2234     Entry.isSExt = isSigned;
   2235     Entry.isZExt = !isSigned;
   2236     Args.push_back(Entry);
   2237   }
   2238 
   2239   // Also pass the return address of the remainder.
   2240   SDValue FIPtr = DAG.CreateStackTemporary(RetVT);
   2241   Entry.Node = FIPtr;
   2242   Entry.Ty = RetTy->getPointerTo();
   2243   Entry.isSExt = isSigned;
   2244   Entry.isZExt = !isSigned;
   2245   Args.push_back(Entry);
   2246 
   2247   SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC),
   2248                                          TLI.getPointerTy());
   2249 
   2250   // Splice the libcall in wherever FindInputOutputChains tells us to.
   2251   DebugLoc dl = Node->getDebugLoc();
   2252   std::pair<SDValue, SDValue> CallInfo =
   2253     TLI.LowerCallTo(InChain, RetTy, isSigned, !isSigned, false, false,
   2254                     0, TLI.getLibcallCallingConv(LC), /*isTailCall=*/false,
   2255                     /*isReturnValueUsed=*/true, Callee, Args, DAG, dl);
   2256 
   2257   // Legalize the call sequence, starting with the chain.  This will advance
   2258   // the LastCALLSEQ to the legalized version of the CALLSEQ_END node that
   2259   // was added by LowerCallTo (guaranteeing proper serialization of calls).
   2260   LegalizeOp(CallInfo.second);
   2261 
   2262   // Remainder is loaded back from the stack frame.
   2263   SDValue Rem = DAG.getLoad(RetVT, dl, LastCALLSEQ_END, FIPtr,
   2264                             MachinePointerInfo(), false, false, 0);
   2265   Results.push_back(CallInfo.first);
   2266   Results.push_back(Rem);
   2267 }
   2268 
   2269 /// ExpandLegalINT_TO_FP - This function is responsible for legalizing a
   2270 /// INT_TO_FP operation of the specified operand when the target requests that
   2271 /// we expand it.  At this point, we know that the result and operand types are
   2272 /// legal for the target.
   2273 SDValue SelectionDAGLegalize::ExpandLegalINT_TO_FP(bool isSigned,
   2274                                                    SDValue Op0,
   2275                                                    EVT DestVT,
   2276                                                    DebugLoc dl) {
   2277   if (Op0.getValueType() == MVT::i32) {
   2278     // simple 32-bit [signed|unsigned] integer to float/double expansion
   2279 
   2280     // Get the stack frame index of a 8 byte buffer.
   2281     SDValue StackSlot = DAG.CreateStackTemporary(MVT::f64);
   2282 
   2283     // word offset constant for Hi/Lo address computation
   2284     SDValue WordOff = DAG.getConstant(sizeof(int), TLI.getPointerTy());
   2285     // set up Hi and Lo (into buffer) address based on endian
   2286     SDValue Hi = StackSlot;
   2287     SDValue Lo = DAG.getNode(ISD::ADD, dl,
   2288                              TLI.getPointerTy(), StackSlot, WordOff);
   2289     if (TLI.isLittleEndian())
   2290       std::swap(Hi, Lo);
   2291 
   2292     // if signed map to unsigned space
   2293     SDValue Op0Mapped;
   2294     if (isSigned) {
   2295       // constant used to invert sign bit (signed to unsigned mapping)
   2296       SDValue SignBit = DAG.getConstant(0x80000000u, MVT::i32);
   2297       Op0Mapped = DAG.getNode(ISD::XOR, dl, MVT::i32, Op0, SignBit);
   2298     } else {
   2299       Op0Mapped = Op0;
   2300     }
   2301     // store the lo of the constructed double - based on integer input
   2302     SDValue Store1 = DAG.getStore(DAG.getEntryNode(), dl,
   2303                                   Op0Mapped, Lo, MachinePointerInfo(),
   2304                                   false, false, 0);
   2305     // initial hi portion of constructed double
   2306     SDValue InitialHi = DAG.getConstant(0x43300000u, MVT::i32);
   2307     // store the hi of the constructed double - biased exponent
   2308     SDValue Store2 = DAG.getStore(Store1, dl, InitialHi, Hi,
   2309                                   MachinePointerInfo(),
   2310                                   false, false, 0);
   2311     // load the constructed double
   2312     SDValue Load = DAG.getLoad(MVT::f64, dl, Store2, StackSlot,
   2313                                MachinePointerInfo(), false, false, 0);
   2314     // FP constant to bias correct the final result
   2315     SDValue Bias = DAG.getConstantFP(isSigned ?
   2316                                      BitsToDouble(0x4330000080000000ULL) :
   2317                                      BitsToDouble(0x4330000000000000ULL),
   2318                                      MVT::f64);
   2319     // subtract the bias
   2320     SDValue Sub = DAG.getNode(ISD::FSUB, dl, MVT::f64, Load, Bias);
   2321     // final result
   2322     SDValue Result;
   2323     // handle final rounding
   2324     if (DestVT == MVT::f64) {
   2325       // do nothing
   2326       Result = Sub;
   2327     } else if (DestVT.bitsLT(MVT::f64)) {
   2328       Result = DAG.getNode(ISD::FP_ROUND, dl, DestVT, Sub,
   2329                            DAG.getIntPtrConstant(0));
   2330     } else if (DestVT.bitsGT(MVT::f64)) {
   2331       Result = DAG.getNode(ISD::FP_EXTEND, dl, DestVT, Sub);
   2332     }
   2333     return Result;
   2334   }
   2335   assert(!isSigned && "Legalize cannot Expand SINT_TO_FP for i64 yet");
   2336   // Code below here assumes !isSigned without checking again.
   2337 
   2338   // Implementation of unsigned i64 to f64 following the algorithm in
   2339   // __floatundidf in compiler_rt. This implementation has the advantage
   2340   // of performing rounding correctly, both in the default rounding mode
   2341   // and in all alternate rounding modes.
   2342   // TODO: Generalize this for use with other types.
   2343   if (Op0.getValueType() == MVT::i64 && DestVT == MVT::f64) {
   2344     SDValue TwoP52 =
   2345       DAG.getConstant(UINT64_C(0x4330000000000000), MVT::i64);
   2346     SDValue TwoP84PlusTwoP52 =
   2347       DAG.getConstantFP(BitsToDouble(UINT64_C(0x4530000000100000)), MVT::f64);
   2348     SDValue TwoP84 =
   2349       DAG.getConstant(UINT64_C(0x4530000000000000), MVT::i64);
   2350 
   2351     SDValue Lo = DAG.getZeroExtendInReg(Op0, dl, MVT::i32);
   2352     SDValue Hi = DAG.getNode(ISD::SRL, dl, MVT::i64, Op0,
   2353                              DAG.getConstant(32, MVT::i64));
   2354     SDValue LoOr = DAG.getNode(ISD::OR, dl, MVT::i64, Lo, TwoP52);
   2355     SDValue HiOr = DAG.getNode(ISD::OR, dl, MVT::i64, Hi, TwoP84);
   2356     SDValue LoFlt = DAG.getNode(ISD::BITCAST, dl, MVT::f64, LoOr);
   2357     SDValue HiFlt = DAG.getNode(ISD::BITCAST, dl, MVT::f64, HiOr);
   2358     SDValue HiSub = DAG.getNode(ISD::FSUB, dl, MVT::f64, HiFlt,
   2359                                 TwoP84PlusTwoP52);
   2360     return DAG.getNode(ISD::FADD, dl, MVT::f64, LoFlt, HiSub);
   2361   }
   2362 
   2363   // Implementation of unsigned i64 to f32.
   2364   // TODO: Generalize this for use with other types.
   2365   if (Op0.getValueType() == MVT::i64 && DestVT == MVT::f32) {
   2366     // For unsigned conversions, convert them to signed conversions using the
   2367     // algorithm from the x86_64 __floatundidf in compiler_rt.
   2368     if (!isSigned) {
   2369       SDValue Fast = DAG.getNode(ISD::SINT_TO_FP, dl, MVT::f32, Op0);
   2370 
   2371       SDValue ShiftConst =
   2372           DAG.getConstant(1, TLI.getShiftAmountTy(Op0.getValueType()));
   2373       SDValue Shr = DAG.getNode(ISD::SRL, dl, MVT::i64, Op0, ShiftConst);
   2374       SDValue AndConst = DAG.getConstant(1, MVT::i64);
   2375       SDValue And = DAG.getNode(ISD::AND, dl, MVT::i64, Op0, AndConst);
   2376       SDValue Or = DAG.getNode(ISD::OR, dl, MVT::i64, And, Shr);
   2377 
   2378       SDValue SignCvt = DAG.getNode(ISD::SINT_TO_FP, dl, MVT::f32, Or);
   2379       SDValue Slow = DAG.getNode(ISD::FADD, dl, MVT::f32, SignCvt, SignCvt);
   2380 
   2381       // TODO: This really should be implemented using a branch rather than a
   2382       // select.  We happen to get lucky and machinesink does the right
   2383       // thing most of the time.  This would be a good candidate for a
   2384       //pseudo-op, or, even better, for whole-function isel.
   2385       SDValue SignBitTest = DAG.getSetCC(dl, TLI.getSetCCResultType(MVT::i64),
   2386         Op0, DAG.getConstant(0, MVT::i64), ISD::SETLT);
   2387       return DAG.getNode(ISD::SELECT, dl, MVT::f32, SignBitTest, Slow, Fast);
   2388     }
   2389 
   2390     // Otherwise, implement the fully general conversion.
   2391 
   2392     SDValue And = DAG.getNode(ISD::AND, dl, MVT::i64, Op0,
   2393          DAG.getConstant(UINT64_C(0xfffffffffffff800), MVT::i64));
   2394     SDValue Or = DAG.getNode(ISD::OR, dl, MVT::i64, And,
   2395          DAG.getConstant(UINT64_C(0x800), MVT::i64));
   2396     SDValue And2 = DAG.getNode(ISD::AND, dl, MVT::i64, Op0,
   2397          DAG.getConstant(UINT64_C(0x7ff), MVT::i64));
   2398     SDValue Ne = DAG.getSetCC(dl, TLI.getSetCCResultType(MVT::i64),
   2399                    And2, DAG.getConstant(UINT64_C(0), MVT::i64), ISD::SETNE);
   2400     SDValue Sel = DAG.getNode(ISD::SELECT, dl, MVT::i64, Ne, Or, Op0);
   2401     SDValue Ge = DAG.getSetCC(dl, TLI.getSetCCResultType(MVT::i64),
   2402                    Op0, DAG.getConstant(UINT64_C(0x0020000000000000), MVT::i64),
   2403                    ISD::SETUGE);
   2404     SDValue Sel2 = DAG.getNode(ISD::SELECT, dl, MVT::i64, Ge, Sel, Op0);
   2405     EVT SHVT = TLI.getShiftAmountTy(Sel2.getValueType());
   2406 
   2407     SDValue Sh = DAG.getNode(ISD::SRL, dl, MVT::i64, Sel2,
   2408                              DAG.getConstant(32, SHVT));
   2409     SDValue Trunc = DAG.getNode(ISD::TRUNCATE, dl, MVT::i32, Sh);
   2410     SDValue Fcvt = DAG.getNode(ISD::UINT_TO_FP, dl, MVT::f64, Trunc);
   2411     SDValue TwoP32 =
   2412       DAG.getConstantFP(BitsToDouble(UINT64_C(0x41f0000000000000)), MVT::f64);
   2413     SDValue Fmul = DAG.getNode(ISD::FMUL, dl, MVT::f64, TwoP32, Fcvt);
   2414     SDValue Lo = DAG.getNode(ISD::TRUNCATE, dl, MVT::i32, Sel2);
   2415     SDValue Fcvt2 = DAG.getNode(ISD::UINT_TO_FP, dl, MVT::f64, Lo);
   2416     SDValue Fadd = DAG.getNode(ISD::FADD, dl, MVT::f64, Fmul, Fcvt2);
   2417     return DAG.getNode(ISD::FP_ROUND, dl, MVT::f32, Fadd,
   2418                        DAG.getIntPtrConstant(0));
   2419   }
   2420 
   2421   SDValue Tmp1 = DAG.getNode(ISD::SINT_TO_FP, dl, DestVT, Op0);
   2422 
   2423   SDValue SignSet = DAG.getSetCC(dl, TLI.getSetCCResultType(Op0.getValueType()),
   2424                                  Op0, DAG.getConstant(0, Op0.getValueType()),
   2425                                  ISD::SETLT);
   2426   SDValue Zero = DAG.getIntPtrConstant(0), Four = DAG.getIntPtrConstant(4);
   2427   SDValue CstOffset = DAG.getNode(ISD::SELECT, dl, Zero.getValueType(),
   2428                                     SignSet, Four, Zero);
   2429 
   2430   // If the sign bit of the integer is set, the large number will be treated
   2431   // as a negative number.  To counteract this, the dynamic code adds an
   2432   // offset depending on the data type.
   2433   uint64_t FF;
   2434   switch (Op0.getValueType().getSimpleVT().SimpleTy) {
   2435   default: assert(0 && "Unsupported integer type!");
   2436   case MVT::i8 : FF = 0x43800000ULL; break;  // 2^8  (as a float)
   2437   case MVT::i16: FF = 0x47800000ULL; break;  // 2^16 (as a float)
   2438   case MVT::i32: FF = 0x4F800000ULL; break;  // 2^32 (as a float)
   2439   case MVT::i64: FF = 0x5F800000ULL; break;  // 2^64 (as a float)
   2440   }
   2441   if (TLI.isLittleEndian()) FF <<= 32;
   2442   Constant *FudgeFactor = ConstantInt::get(
   2443                                        Type::getInt64Ty(*DAG.getContext()), FF);
   2444 
   2445   SDValue CPIdx = DAG.getConstantPool(FudgeFactor, TLI.getPointerTy());
   2446   unsigned Alignment = cast<ConstantPoolSDNode>(CPIdx)->getAlignment();
   2447   CPIdx = DAG.getNode(ISD::ADD, dl, TLI.getPointerTy(), CPIdx, CstOffset);
   2448   Alignment = std::min(Alignment, 4u);
   2449   SDValue FudgeInReg;
   2450   if (DestVT == MVT::f32)
   2451     FudgeInReg = DAG.getLoad(MVT::f32, dl, DAG.getEntryNode(), CPIdx,
   2452                              MachinePointerInfo::getConstantPool(),
   2453                              false, false, Alignment);
   2454   else {
   2455     FudgeInReg =
   2456       LegalizeOp(DAG.getExtLoad(ISD::EXTLOAD, dl, DestVT,
   2457                                 DAG.getEntryNode(), CPIdx,
   2458                                 MachinePointerInfo::getConstantPool(),
   2459                                 MVT::f32, false, false, Alignment));
   2460   }
   2461 
   2462   return DAG.getNode(ISD::FADD, dl, DestVT, Tmp1, FudgeInReg);
   2463 }
   2464 
   2465 /// PromoteLegalINT_TO_FP - This function is responsible for legalizing a
   2466 /// *INT_TO_FP operation of the specified operand when the target requests that
   2467 /// we promote it.  At this point, we know that the result and operand types are
   2468 /// legal for the target, and that there is a legal UINT_TO_FP or SINT_TO_FP
   2469 /// operation that takes a larger input.
   2470 SDValue SelectionDAGLegalize::PromoteLegalINT_TO_FP(SDValue LegalOp,
   2471                                                     EVT DestVT,
   2472                                                     bool isSigned,
   2473                                                     DebugLoc dl) {
   2474   // First step, figure out the appropriate *INT_TO_FP operation to use.
   2475   EVT NewInTy = LegalOp.getValueType();
   2476 
   2477   unsigned OpToUse = 0;
   2478 
   2479   // Scan for the appropriate larger type to use.
   2480   while (1) {
   2481     NewInTy = (MVT::SimpleValueType)(NewInTy.getSimpleVT().SimpleTy+1);
   2482     assert(NewInTy.isInteger() && "Ran out of possibilities!");
   2483 
   2484     // If the target supports SINT_TO_FP of this type, use it.
   2485     if (TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, NewInTy)) {
   2486       OpToUse = ISD::SINT_TO_FP;
   2487       break;
   2488     }
   2489     if (isSigned) continue;
   2490 
   2491     // If the target supports UINT_TO_FP of this type, use it.
   2492     if (TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, NewInTy)) {
   2493       OpToUse = ISD::UINT_TO_FP;
   2494       break;
   2495     }
   2496 
   2497     // Otherwise, try a larger type.
   2498   }
   2499 
   2500   // Okay, we found the operation and type to use.  Zero extend our input to the
   2501   // desired type then run the operation on it.
   2502   return DAG.getNode(OpToUse, dl, DestVT,
   2503                      DAG.getNode(isSigned ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND,
   2504                                  dl, NewInTy, LegalOp));
   2505 }
   2506 
   2507 /// PromoteLegalFP_TO_INT - This function is responsible for legalizing a
   2508 /// FP_TO_*INT operation of the specified operand when the target requests that
   2509 /// we promote it.  At this point, we know that the result and operand types are
   2510 /// legal for the target, and that there is a legal FP_TO_UINT or FP_TO_SINT
   2511 /// operation that returns a larger result.
   2512 SDValue SelectionDAGLegalize::PromoteLegalFP_TO_INT(SDValue LegalOp,
   2513                                                     EVT DestVT,
   2514                                                     bool isSigned,
   2515                                                     DebugLoc dl) {
   2516   // First step, figure out the appropriate FP_TO*INT operation to use.
   2517   EVT NewOutTy = DestVT;
   2518 
   2519   unsigned OpToUse = 0;
   2520 
   2521   // Scan for the appropriate larger type to use.
   2522   while (1) {
   2523     NewOutTy = (MVT::SimpleValueType)(NewOutTy.getSimpleVT().SimpleTy+1);
   2524     assert(NewOutTy.isInteger() && "Ran out of possibilities!");
   2525 
   2526     if (TLI.isOperationLegalOrCustom(ISD::FP_TO_SINT, NewOutTy)) {
   2527       OpToUse = ISD::FP_TO_SINT;
   2528       break;
   2529     }
   2530 
   2531     if (TLI.isOperationLegalOrCustom(ISD::FP_TO_UINT, NewOutTy)) {
   2532       OpToUse = ISD::FP_TO_UINT;
   2533       break;
   2534     }
   2535 
   2536     // Otherwise, try a larger type.
   2537   }
   2538 
   2539 
   2540   // Okay, we found the operation and type to use.
   2541   SDValue Operation = DAG.getNode(OpToUse, dl, NewOutTy, LegalOp);
   2542 
   2543   // Truncate the result of the extended FP_TO_*INT operation to the desired
   2544   // size.
   2545   return DAG.getNode(ISD::TRUNCATE, dl, DestVT, Operation);
   2546 }
   2547 
   2548 /// ExpandBSWAP - Open code the operations for BSWAP of the specified operation.
   2549 ///
   2550 SDValue SelectionDAGLegalize::ExpandBSWAP(SDValue Op, DebugLoc dl) {
   2551   EVT VT = Op.getValueType();
   2552   EVT SHVT = TLI.getShiftAmountTy(VT);
   2553   SDValue Tmp1, Tmp2, Tmp3, Tmp4, Tmp5, Tmp6, Tmp7, Tmp8;
   2554   switch (VT.getSimpleVT().SimpleTy) {
   2555   default: assert(0 && "Unhandled Expand type in BSWAP!");
   2556   case MVT::i16:
   2557     Tmp2 = DAG.getNode(ISD::SHL, dl, VT, Op, DAG.getConstant(8, SHVT));
   2558     Tmp1 = DAG.getNode(ISD::SRL, dl, VT, Op, DAG.getConstant(8, SHVT));
   2559     return DAG.getNode(ISD::OR, dl, VT, Tmp1, Tmp2);
   2560   case MVT::i32:
   2561     Tmp4 = DAG.getNode(ISD::SHL, dl, VT, Op, DAG.getConstant(24, SHVT));
   2562     Tmp3 = DAG.getNode(ISD::SHL, dl, VT, Op, DAG.getConstant(8, SHVT));
   2563     Tmp2 = DAG.getNode(ISD::SRL, dl, VT, Op, DAG.getConstant(8, SHVT));
   2564     Tmp1 = DAG.getNode(ISD::SRL, dl, VT, Op, DAG.getConstant(24, SHVT));
   2565     Tmp3 = DAG.getNode(ISD::AND, dl, VT, Tmp3, DAG.getConstant(0xFF0000, VT));
   2566     Tmp2 = DAG.getNode(ISD::AND, dl, VT, Tmp2, DAG.getConstant(0xFF00, VT));
   2567     Tmp4 = DAG.getNode(ISD::OR, dl, VT, Tmp4, Tmp3);
   2568     Tmp2 = DAG.getNode(ISD::OR, dl, VT, Tmp2, Tmp1);
   2569     return DAG.getNode(ISD::OR, dl, VT, Tmp4, Tmp2);
   2570   case MVT::i64:
   2571     Tmp8 = DAG.getNode(ISD::SHL, dl, VT, Op, DAG.getConstant(56, SHVT));
   2572     Tmp7 = DAG.getNode(ISD::SHL, dl, VT, Op, DAG.getConstant(40, SHVT));
   2573     Tmp6 = DAG.getNode(ISD::SHL, dl, VT, Op, DAG.getConstant(24, SHVT));
   2574     Tmp5 = DAG.getNode(ISD::SHL, dl, VT, Op, DAG.getConstant(8, SHVT));
   2575     Tmp4 = DAG.getNode(ISD::SRL, dl, VT, Op, DAG.getConstant(8, SHVT));
   2576     Tmp3 = DAG.getNode(ISD::SRL, dl, VT, Op, DAG.getConstant(24, SHVT));
   2577     Tmp2 = DAG.getNode(ISD::SRL, dl, VT, Op, DAG.getConstant(40, SHVT));
   2578     Tmp1 = DAG.getNode(ISD::SRL, dl, VT, Op, DAG.getConstant(56, SHVT));
   2579     Tmp7 = DAG.getNode(ISD::AND, dl, VT, Tmp7, DAG.getConstant(255ULL<<48, VT));
   2580     Tmp6 = DAG.getNode(ISD::AND, dl, VT, Tmp6, DAG.getConstant(255ULL<<40, VT));
   2581     Tmp5 = DAG.getNode(ISD::AND, dl, VT, Tmp5, DAG.getConstant(255ULL<<32, VT));
   2582     Tmp4 = DAG.getNode(ISD::AND, dl, VT, Tmp4, DAG.getConstant(255ULL<<24, VT));
   2583     Tmp3 = DAG.getNode(ISD::AND, dl, VT, Tmp3, DAG.getConstant(255ULL<<16, VT));
   2584     Tmp2 = DAG.getNode(ISD::AND, dl, VT, Tmp2, DAG.getConstant(255ULL<<8 , VT));
   2585     Tmp8 = DAG.getNode(ISD::OR, dl, VT, Tmp8, Tmp7);
   2586     Tmp6 = DAG.getNode(ISD::OR, dl, VT, Tmp6, Tmp5);
   2587     Tmp4 = DAG.getNode(ISD::OR, dl, VT, Tmp4, Tmp3);
   2588     Tmp2 = DAG.getNode(ISD::OR, dl, VT, Tmp2, Tmp1);
   2589     Tmp8 = DAG.getNode(ISD::OR, dl, VT, Tmp8, Tmp6);
   2590     Tmp4 = DAG.getNode(ISD::OR, dl, VT, Tmp4, Tmp2);
   2591     return DAG.getNode(ISD::OR, dl, VT, Tmp8, Tmp4);
   2592   }
   2593 }
   2594 
   2595 /// SplatByte - Distribute ByteVal over NumBits bits.
   2596 // FIXME: Move this helper to a common place.
   2597 static APInt SplatByte(unsigned NumBits, uint8_t ByteVal) {
   2598   APInt Val = APInt(NumBits, ByteVal);
   2599   unsigned Shift = 8;
   2600   for (unsigned i = NumBits; i > 8; i >>= 1) {
   2601     Val = (Val << Shift) | Val;
   2602     Shift <<= 1;
   2603   }
   2604   return Val;
   2605 }
   2606 
   2607 /// ExpandBitCount - Expand the specified bitcount instruction into operations.
   2608 ///
   2609 SDValue SelectionDAGLegalize::ExpandBitCount(unsigned Opc, SDValue Op,
   2610                                              DebugLoc dl) {
   2611   switch (Opc) {
   2612   default: assert(0 && "Cannot expand this yet!");
   2613   case ISD::CTPOP: {
   2614     EVT VT = Op.getValueType();
   2615     EVT ShVT = TLI.getShiftAmountTy(VT);
   2616     unsigned Len = VT.getSizeInBits();
   2617 
   2618     assert(VT.isInteger() && Len <= 128 && Len % 8 == 0 &&
   2619            "CTPOP not implemented for this type.");
   2620 
   2621     // This is the "best" algorithm from
   2622     // http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
   2623 
   2624     SDValue Mask55 = DAG.getConstant(SplatByte(Len, 0x55), VT);
   2625     SDValue Mask33 = DAG.getConstant(SplatByte(Len, 0x33), VT);
   2626     SDValue Mask0F = DAG.getConstant(SplatByte(Len, 0x0F), VT);
   2627     SDValue Mask01 = DAG.getConstant(SplatByte(Len, 0x01), VT);
   2628 
   2629     // v = v - ((v >> 1) & 0x55555555...)
   2630     Op = DAG.getNode(ISD::SUB, dl, VT, Op,
   2631                      DAG.getNode(ISD::AND, dl, VT,
   2632                                  DAG.getNode(ISD::SRL, dl, VT, Op,
   2633                                              DAG.getConstant(1, ShVT)),
   2634                                  Mask55));
   2635     // v = (v & 0x33333333...) + ((v >> 2) & 0x33333333...)
   2636     Op = DAG.getNode(ISD::ADD, dl, VT,
   2637                      DAG.getNode(ISD::AND, dl, VT, Op, Mask33),
   2638                      DAG.getNode(ISD::AND, dl, VT,
   2639                                  DAG.getNode(ISD::SRL, dl, VT, Op,
   2640                                              DAG.getConstant(2, ShVT)),
   2641                                  Mask33));
   2642     // v = (v + (v >> 4)) & 0x0F0F0F0F...
   2643     Op = DAG.getNode(ISD::AND, dl, VT,
   2644                      DAG.getNode(ISD::ADD, dl, VT, Op,
   2645                                  DAG.getNode(ISD::SRL, dl, VT, Op,
   2646                                              DAG.getConstant(4, ShVT))),
   2647                      Mask0F);
   2648     // v = (v * 0x01010101...) >> (Len - 8)
   2649     Op = DAG.getNode(ISD::SRL, dl, VT,
   2650                      DAG.getNode(ISD::MUL, dl, VT, Op, Mask01),
   2651                      DAG.getConstant(Len - 8, ShVT));
   2652 
   2653     return Op;
   2654   }
   2655   case ISD::CTLZ: {
   2656     // for now, we do this:
   2657     // x = x | (x >> 1);
   2658     // x = x | (x >> 2);
   2659     // ...
   2660     // x = x | (x >>16);
   2661     // x = x | (x >>32); // for 64-bit input
   2662     // return popcount(~x);
   2663     //
   2664     // but see also: http://www.hackersdelight.org/HDcode/nlz.cc
   2665     EVT VT = Op.getValueType();
   2666     EVT ShVT = TLI.getShiftAmountTy(VT);
   2667     unsigned len = VT.getSizeInBits();
   2668     for (unsigned i = 0; (1U << i) <= (len / 2); ++i) {
   2669       SDValue Tmp3 = DAG.getConstant(1ULL << i, ShVT);
   2670       Op = DAG.getNode(ISD::OR, dl, VT, Op,
   2671                        DAG.getNode(ISD::SRL, dl, VT, Op, Tmp3));
   2672     }
   2673     Op = DAG.getNOT(dl, Op, VT);
   2674     return DAG.getNode(ISD::CTPOP, dl, VT, Op);
   2675   }
   2676   case ISD::CTTZ: {
   2677     // for now, we use: { return popcount(~x & (x - 1)); }
   2678     // unless the target has ctlz but not ctpop, in which case we use:
   2679     // { return 32 - nlz(~x & (x-1)); }
   2680     // see also http://www.hackersdelight.org/HDcode/ntz.cc
   2681     EVT VT = Op.getValueType();
   2682     SDValue Tmp3 = DAG.getNode(ISD::AND, dl, VT,
   2683                                DAG.getNOT(dl, Op, VT),
   2684                                DAG.getNode(ISD::SUB, dl, VT, Op,
   2685                                            DAG.getConstant(1, VT)));
   2686     // If ISD::CTLZ is legal and CTPOP isn't, then do that instead.
   2687     if (!TLI.isOperationLegalOrCustom(ISD::CTPOP, VT) &&
   2688         TLI.isOperationLegalOrCustom(ISD::CTLZ, VT))
   2689       return DAG.getNode(ISD::SUB, dl, VT,
   2690                          DAG.getConstant(VT.getSizeInBits(), VT),
   2691                          DAG.getNode(ISD::CTLZ, dl, VT, Tmp3));
   2692     return DAG.getNode(ISD::CTPOP, dl, VT, Tmp3);
   2693   }
   2694   }
   2695 }
   2696 
   2697 std::pair <SDValue, SDValue> SelectionDAGLegalize::ExpandAtomic(SDNode *Node) {
   2698   unsigned Opc = Node->getOpcode();
   2699   MVT VT = cast<AtomicSDNode>(Node)->getMemoryVT().getSimpleVT();
   2700   RTLIB::Libcall LC;
   2701 
   2702   switch (Opc) {
   2703   default:
   2704     llvm_unreachable("Unhandled atomic intrinsic Expand!");
   2705     break;
   2706   case ISD::ATOMIC_SWAP:
   2707     switch (VT.SimpleTy) {
   2708     default: llvm_unreachable("Unexpected value type for atomic!");
   2709     case MVT::i8:  LC = RTLIB::SYNC_LOCK_TEST_AND_SET_1; break;
   2710     case MVT::i16: LC = RTLIB::SYNC_LOCK_TEST_AND_SET_2; break;
   2711     case MVT::i32: LC = RTLIB::SYNC_LOCK_TEST_AND_SET_4; break;
   2712     case MVT::i64: LC = RTLIB::SYNC_LOCK_TEST_AND_SET_8; break;
   2713     }
   2714     break;
   2715   case ISD::ATOMIC_CMP_SWAP:
   2716     switch (VT.SimpleTy) {
   2717     default: llvm_unreachable("Unexpected value type for atomic!");
   2718     case MVT::i8:  LC = RTLIB::SYNC_VAL_COMPARE_AND_SWAP_1; break;
   2719     case MVT::i16: LC = RTLIB::SYNC_VAL_COMPARE_AND_SWAP_2; break;
   2720     case MVT::i32: LC = RTLIB::SYNC_VAL_COMPARE_AND_SWAP_4; break;
   2721     case MVT::i64: LC = RTLIB::SYNC_VAL_COMPARE_AND_SWAP_8; break;
   2722     }
   2723     break;
   2724   case ISD::ATOMIC_LOAD_ADD:
   2725     switch (VT.SimpleTy) {
   2726     default: llvm_unreachable("Unexpected value type for atomic!");
   2727     case MVT::i8:  LC = RTLIB::SYNC_FETCH_AND_ADD_1; break;
   2728     case MVT::i16: LC = RTLIB::SYNC_FETCH_AND_ADD_2; break;
   2729     case MVT::i32: LC = RTLIB::SYNC_FETCH_AND_ADD_4; break;
   2730     case MVT::i64: LC = RTLIB::SYNC_FETCH_AND_ADD_8; break;
   2731     }
   2732     break;
   2733   case ISD::ATOMIC_LOAD_SUB:
   2734     switch (VT.SimpleTy) {
   2735     default: llvm_unreachable("Unexpected value type for atomic!");
   2736     case MVT::i8:  LC = RTLIB::SYNC_FETCH_AND_SUB_1; break;
   2737     case MVT::i16: LC = RTLIB::SYNC_FETCH_AND_SUB_2; break;
   2738     case MVT::i32: LC = RTLIB::SYNC_FETCH_AND_SUB_4; break;
   2739     case MVT::i64: LC = RTLIB::SYNC_FETCH_AND_SUB_8; break;
   2740     }
   2741     break;
   2742   case ISD::ATOMIC_LOAD_AND:
   2743     switch (VT.SimpleTy) {
   2744     default: llvm_unreachable("Unexpected value type for atomic!");
   2745     case MVT::i8:  LC = RTLIB::SYNC_FETCH_AND_AND_1; break;
   2746     case MVT::i16: LC = RTLIB::SYNC_FETCH_AND_AND_2; break;
   2747     case MVT::i32: LC = RTLIB::SYNC_FETCH_AND_AND_4; break;
   2748     case MVT::i64: LC = RTLIB::SYNC_FETCH_AND_AND_8; break;
   2749     }
   2750     break;
   2751   case ISD::ATOMIC_LOAD_OR:
   2752     switch (VT.SimpleTy) {
   2753     default: llvm_unreachable("Unexpected value type for atomic!");
   2754     case MVT::i8:  LC = RTLIB::SYNC_FETCH_AND_OR_1; break;
   2755     case MVT::i16: LC = RTLIB::SYNC_FETCH_AND_OR_2; break;
   2756     case MVT::i32: LC = RTLIB::SYNC_FETCH_AND_OR_4; break;
   2757     case MVT::i64: LC = RTLIB::SYNC_FETCH_AND_OR_8; break;
   2758     }
   2759     break;
   2760   case ISD::ATOMIC_LOAD_XOR:
   2761     switch (VT.SimpleTy) {
   2762     default: llvm_unreachable("Unexpected value type for atomic!");
   2763     case MVT::i8:  LC = RTLIB::SYNC_FETCH_AND_XOR_1; break;
   2764     case MVT::i16: LC = RTLIB::SYNC_FETCH_AND_XOR_2; break;
   2765     case MVT::i32: LC = RTLIB::SYNC_FETCH_AND_XOR_4; break;
   2766     case MVT::i64: LC = RTLIB::SYNC_FETCH_AND_XOR_8; break;
   2767     }
   2768     break;
   2769   case ISD::ATOMIC_LOAD_NAND:
   2770     switch (VT.SimpleTy) {
   2771     default: llvm_unreachable("Unexpected value type for atomic!");
   2772     case MVT::i8:  LC = RTLIB::SYNC_FETCH_AND_NAND_1; break;
   2773     case MVT::i16: LC = RTLIB::SYNC_FETCH_AND_NAND_2; break;
   2774     case MVT::i32: LC = RTLIB::SYNC_FETCH_AND_NAND_4; break;
   2775     case MVT::i64: LC = RTLIB::SYNC_FETCH_AND_NAND_8; break;
   2776     }
   2777     break;
   2778   }
   2779 
   2780   return ExpandChainLibCall(LC, Node, false);
   2781 }
   2782 
   2783 void SelectionDAGLegalize::ExpandNode(SDNode *Node,
   2784                                       SmallVectorImpl<SDValue> &Results) {
   2785   DebugLoc dl = Node->getDebugLoc();
   2786   SDValue Tmp1, Tmp2, Tmp3, Tmp4;
   2787   switch (Node->getOpcode()) {
   2788   case ISD::CTPOP:
   2789   case ISD::CTLZ:
   2790   case ISD::CTTZ:
   2791     Tmp1 = ExpandBitCount(Node->getOpcode(), Node->getOperand(0), dl);
   2792     Results.push_back(Tmp1);
   2793     break;
   2794   case ISD::BSWAP:
   2795     Results.push_back(ExpandBSWAP(Node->getOperand(0), dl));
   2796     break;
   2797   case ISD::FRAMEADDR:
   2798   case ISD::RETURNADDR:
   2799   case ISD::FRAME_TO_ARGS_OFFSET:
   2800     Results.push_back(DAG.getConstant(0, Node->getValueType(0)));
   2801     break;
   2802   case ISD::FLT_ROUNDS_:
   2803     Results.push_back(DAG.getConstant(1, Node->getValueType(0)));
   2804     break;
   2805   case ISD::EH_RETURN:
   2806   case ISD::EH_LABEL:
   2807   case ISD::PREFETCH:
   2808   case ISD::VAEND:
   2809   case ISD::EH_SJLJ_LONGJMP:
   2810   case ISD::EH_SJLJ_DISPATCHSETUP:
   2811     // If the target didn't expand these, there's nothing to do, so just
   2812     // preserve the chain and be done.
   2813     Results.push_back(Node->getOperand(0));
   2814     break;
   2815   case ISD::EH_SJLJ_SETJMP:
   2816     // If the target didn't expand this, just return 'zero' and preserve the
   2817     // chain.
   2818     Results.push_back(DAG.getConstant(0, MVT::i32));
   2819     Results.push_back(Node->getOperand(0));
   2820     break;
   2821   case ISD::ATOMIC_FENCE:
   2822   case ISD::MEMBARRIER: {
   2823     // If the target didn't lower this, lower it to '__sync_synchronize()' call
   2824     // FIXME: handle "fence singlethread" more efficiently.
   2825     TargetLowering::ArgListTy Args;
   2826     std::pair<SDValue, SDValue> CallResult =
   2827       TLI.LowerCallTo(Node->getOperand(0), Type::getVoidTy(*DAG.getContext()),
   2828                       false, false, false, false, 0, CallingConv::C,
   2829                       /*isTailCall=*/false,
   2830                       /*isReturnValueUsed=*/true,
   2831                       DAG.getExternalSymbol("__sync_synchronize",
   2832                                             TLI.getPointerTy()),
   2833                       Args, DAG, dl);
   2834     Results.push_back(CallResult.second);
   2835     break;
   2836   }
   2837   case ISD::ATOMIC_LOAD: {
   2838     // There is no libcall for atomic load; fake it with ATOMIC_CMP_SWAP.
   2839     SDValue Zero = DAG.getConstant(0, Node->getValueType(0));
   2840     SDValue Swap = DAG.getAtomic(ISD::ATOMIC_CMP_SWAP, dl,
   2841                                  cast<AtomicSDNode>(Node)->getMemoryVT(),
   2842                                  Node->getOperand(0),
   2843                                  Node->getOperand(1), Zero, Zero,
   2844                                  cast<AtomicSDNode>(Node)->getMemOperand(),
   2845                                  cast<AtomicSDNode>(Node)->getOrdering(),
   2846                                  cast<AtomicSDNode>(Node)->getSynchScope());
   2847     Results.push_back(Swap.getValue(0));
   2848     Results.push_back(Swap.getValue(1));
   2849     break;
   2850   }
   2851   case ISD::ATOMIC_STORE: {
   2852     // There is no libcall for atomic store; fake it with ATOMIC_SWAP.
   2853     SDValue Swap = DAG.getAtomic(ISD::ATOMIC_SWAP, dl,
   2854                                  cast<AtomicSDNode>(Node)->getMemoryVT(),
   2855                                  Node->getOperand(0),
   2856                                  Node->getOperand(1), Node->getOperand(2),
   2857                                  cast<AtomicSDNode>(Node)->getMemOperand(),
   2858                                  cast<AtomicSDNode>(Node)->getOrdering(),
   2859                                  cast<AtomicSDNode>(Node)->getSynchScope());
   2860     Results.push_back(Swap.getValue(1));
   2861     break;
   2862   }
   2863   // By default, atomic intrinsics are marked Legal and lowered. Targets
   2864   // which don't support them directly, however, may want libcalls, in which
   2865   // case they mark them Expand, and we get here.
   2866   case ISD::ATOMIC_SWAP:
   2867   case ISD::ATOMIC_LOAD_ADD:
   2868   case ISD::ATOMIC_LOAD_SUB:
   2869   case ISD::ATOMIC_LOAD_AND:
   2870   case ISD::ATOMIC_LOAD_OR:
   2871   case ISD::ATOMIC_LOAD_XOR:
   2872   case ISD::ATOMIC_LOAD_NAND:
   2873   case ISD::ATOMIC_LOAD_MIN:
   2874   case ISD::ATOMIC_LOAD_MAX:
   2875   case ISD::ATOMIC_LOAD_UMIN:
   2876   case ISD::ATOMIC_LOAD_UMAX:
   2877   case ISD::ATOMIC_CMP_SWAP: {
   2878     std::pair<SDValue, SDValue> Tmp = ExpandAtomic(Node);
   2879     Results.push_back(Tmp.first);
   2880     Results.push_back(Tmp.second);
   2881     break;
   2882   }
   2883   case ISD::DYNAMIC_STACKALLOC:
   2884     ExpandDYNAMIC_STACKALLOC(Node, Results);
   2885     break;
   2886   case ISD::MERGE_VALUES:
   2887     for (unsigned i = 0; i < Node->getNumValues(); i++)
   2888       Results.push_back(Node->getOperand(i));
   2889     break;
   2890   case ISD::UNDEF: {
   2891     EVT VT = Node->getValueType(0);
   2892     if (VT.isInteger())
   2893       Results.push_back(DAG.getConstant(0, VT));
   2894     else {
   2895       assert(VT.isFloatingPoint() && "Unknown value type!");
   2896       Results.push_back(DAG.getConstantFP(0, VT));
   2897     }
   2898     break;
   2899   }
   2900   case ISD::TRAP: {
   2901     // If this operation is not supported, lower it to 'abort()' call
   2902     TargetLowering::ArgListTy Args;
   2903     std::pair<SDValue, SDValue> CallResult =
   2904       TLI.LowerCallTo(Node->getOperand(0), Type::getVoidTy(*DAG.getContext()),
   2905                       false, false, false, false, 0, CallingConv::C,
   2906                       /*isTailCall=*/false,
   2907                       /*isReturnValueUsed=*/true,
   2908                       DAG.getExternalSymbol("abort", TLI.getPointerTy()),
   2909                       Args, DAG, dl);
   2910     Results.push_back(CallResult.second);
   2911     break;
   2912   }
   2913   case ISD::FP_ROUND:
   2914   case ISD::BITCAST:
   2915     Tmp1 = EmitStackConvert(Node->getOperand(0), Node->getValueType(0),
   2916                             Node->getValueType(0), dl);
   2917     Results.push_back(Tmp1);
   2918     break;
   2919   case ISD::FP_EXTEND:
   2920     Tmp1 = EmitStackConvert(Node->getOperand(0),
   2921                             Node->getOperand(0).getValueType(),
   2922                             Node->getValueType(0), dl);
   2923     Results.push_back(Tmp1);
   2924     break;
   2925   case ISD::SIGN_EXTEND_INREG: {
   2926     // NOTE: we could fall back on load/store here too for targets without
   2927     // SAR.  However, it is doubtful that any exist.
   2928     EVT ExtraVT = cast<VTSDNode>(Node->getOperand(1))->getVT();
   2929     EVT VT = Node->getValueType(0);
   2930     EVT ShiftAmountTy = TLI.getShiftAmountTy(VT);
   2931     if (VT.isVector())
   2932       ShiftAmountTy = VT;
   2933     unsigned BitsDiff = VT.getScalarType().getSizeInBits() -
   2934                         ExtraVT.getScalarType().getSizeInBits();
   2935     SDValue ShiftCst = DAG.getConstant(BitsDiff, ShiftAmountTy);
   2936     Tmp1 = DAG.getNode(ISD::SHL, dl, Node->getValueType(0),
   2937                        Node->getOperand(0), ShiftCst);
   2938     Tmp1 = DAG.getNode(ISD::SRA, dl, Node->getValueType(0), Tmp1, ShiftCst);
   2939     Results.push_back(Tmp1);
   2940     break;
   2941   }
   2942   case ISD::FP_ROUND_INREG: {
   2943     // The only way we can lower this is to turn it into a TRUNCSTORE,
   2944     // EXTLOAD pair, targeting a temporary location (a stack slot).
   2945 
   2946     // NOTE: there is a choice here between constantly creating new stack
   2947     // slots and always reusing the same one.  We currently always create
   2948     // new ones, as reuse may inhibit scheduling.
   2949     EVT ExtraVT = cast<VTSDNode>(Node->getOperand(1))->getVT();
   2950     Tmp1 = EmitStackConvert(Node->getOperand(0), ExtraVT,
   2951                             Node->getValueType(0), dl);
   2952     Results.push_back(Tmp1);
   2953     break;
   2954   }
   2955   case ISD::SINT_TO_FP:
   2956   case ISD::UINT_TO_FP:
   2957     Tmp1 = ExpandLegalINT_TO_FP(Node->getOpcode() == ISD::SINT_TO_FP,
   2958                                 Node->getOperand(0), Node->getValueType(0), dl);
   2959     Results.push_back(Tmp1);
   2960     break;
   2961   case ISD::FP_TO_UINT: {
   2962     SDValue True, False;
   2963     EVT VT =  Node->getOperand(0).getValueType();
   2964     EVT NVT = Node->getValueType(0);
   2965     APFloat apf(APInt::getNullValue(VT.getSizeInBits()));
   2966     APInt x = APInt::getSignBit(NVT.getSizeInBits());
   2967     (void)apf.convertFromAPInt(x, false, APFloat::rmNearestTiesToEven);
   2968     Tmp1 = DAG.getConstantFP(apf, VT);
   2969     Tmp2 = DAG.getSetCC(dl, TLI.getSetCCResultType(VT),
   2970                         Node->getOperand(0),
   2971                         Tmp1, ISD::SETLT);
   2972     True = DAG.getNode(ISD::FP_TO_SINT, dl, NVT, Node->getOperand(0));
   2973     False = DAG.getNode(ISD::FP_TO_SINT, dl, NVT,
   2974                         DAG.getNode(ISD::FSUB, dl, VT,
   2975                                     Node->getOperand(0), Tmp1));
   2976     False = DAG.getNode(ISD::XOR, dl, NVT, False,
   2977                         DAG.getConstant(x, NVT));
   2978     Tmp1 = DAG.getNode(ISD::SELECT, dl, NVT, Tmp2, True, False);
   2979     Results.push_back(Tmp1);
   2980     break;
   2981   }
   2982   case ISD::VAARG: {
   2983     const Value *V = cast<SrcValueSDNode>(Node->getOperand(2))->getValue();
   2984     EVT VT = Node->getValueType(0);
   2985     Tmp1 = Node->getOperand(0);
   2986     Tmp2 = Node->getOperand(1);
   2987     unsigned Align = Node->getConstantOperandVal(3);
   2988 
   2989     SDValue VAListLoad = DAG.getLoad(TLI.getPointerTy(), dl, Tmp1, Tmp2,
   2990                                      MachinePointerInfo(V), false, false, 0);
   2991     SDValue VAList = VAListLoad;
   2992 
   2993     if (Align > TLI.getMinStackArgumentAlignment()) {
   2994       assert(((Align & (Align-1)) == 0) && "Expected Align to be a power of 2");
   2995 
   2996       VAList = DAG.getNode(ISD::ADD, dl, TLI.getPointerTy(), VAList,
   2997                            DAG.getConstant(Align - 1,
   2998                                            TLI.getPointerTy()));
   2999 
   3000       VAList = DAG.getNode(ISD::AND, dl, TLI.getPointerTy(), VAList,
   3001                            DAG.getConstant(-(int64_t)Align,
   3002                                            TLI.getPointerTy()));
   3003     }
   3004 
   3005     // Increment the pointer, VAList, to the next vaarg
   3006     Tmp3 = DAG.getNode(ISD::ADD, dl, TLI.getPointerTy(), VAList,
   3007                        DAG.getConstant(TLI.getTargetData()->
   3008                           getTypeAllocSize(VT.getTypeForEVT(*DAG.getContext())),
   3009                                        TLI.getPointerTy()));
   3010     // Store the incremented VAList to the legalized pointer
   3011     Tmp3 = DAG.getStore(VAListLoad.getValue(1), dl, Tmp3, Tmp2,
   3012                         MachinePointerInfo(V), false, false, 0);
   3013     // Load the actual argument out of the pointer VAList
   3014     Results.push_back(DAG.getLoad(VT, dl, Tmp3, VAList, MachinePointerInfo(),
   3015                                   false, false, 0));
   3016     Results.push_back(Results[0].getValue(1));
   3017     break;
   3018   }
   3019   case ISD::VACOPY: {
   3020     // This defaults to loading a pointer from the input and storing it to the
   3021     // output, returning the chain.
   3022     const Value *VD = cast<SrcValueSDNode>(Node->getOperand(3))->getValue();
   3023     const Value *VS = cast<SrcValueSDNode>(Node->getOperand(4))->getValue();
   3024     Tmp1 = DAG.getLoad(TLI.getPointerTy(), dl, Node->getOperand(0),
   3025                        Node->getOperand(2), MachinePointerInfo(VS),
   3026                        false, false, 0);
   3027     Tmp1 = DAG.getStore(Tmp1.getValue(1), dl, Tmp1, Node->getOperand(1),
   3028                         MachinePointerInfo(VD), false, false, 0);
   3029     Results.push_back(Tmp1);
   3030     break;
   3031   }
   3032   case ISD::EXTRACT_VECTOR_ELT:
   3033     if (Node->getOperand(0).getValueType().getVectorNumElements() == 1)
   3034       // This must be an access of the only element.  Return it.
   3035       Tmp1 = DAG.getNode(ISD::BITCAST, dl, Node->getValueType(0),
   3036                          Node->getOperand(0));
   3037     else
   3038       Tmp1 = ExpandExtractFromVectorThroughStack(SDValue(Node, 0));
   3039     Results.push_back(Tmp1);
   3040     break;
   3041   case ISD::EXTRACT_SUBVECTOR:
   3042     Results.push_back(ExpandExtractFromVectorThroughStack(SDValue(Node, 0)));
   3043     break;
   3044   case ISD::INSERT_SUBVECTOR:
   3045     Results.push_back(ExpandInsertToVectorThroughStack(SDValue(Node, 0)));
   3046     break;
   3047   case ISD::CONCAT_VECTORS: {
   3048     Results.push_back(ExpandVectorBuildThroughStack(Node));
   3049     break;
   3050   }
   3051   case ISD::SCALAR_TO_VECTOR:
   3052     Results.push_back(ExpandSCALAR_TO_VECTOR(Node));
   3053     break;
   3054   case ISD::INSERT_VECTOR_ELT:
   3055     Results.push_back(ExpandINSERT_VECTOR_ELT(Node->getOperand(0),
   3056                                               Node->getOperand(1),
   3057                                               Node->getOperand(2), dl));
   3058     break;
   3059   case ISD::VECTOR_SHUFFLE: {
   3060     SmallVector<int, 8> Mask;
   3061     cast<ShuffleVectorSDNode>(Node)->getMask(Mask);
   3062 
   3063     EVT VT = Node->getValueType(0);
   3064     EVT EltVT = VT.getVectorElementType();
   3065     if (!TLI.isTypeLegal(EltVT))
   3066       EltVT = TLI.getTypeToTransformTo(*DAG.getContext(), EltVT);
   3067     unsigned NumElems = VT.getVectorNumElements();
   3068     SmallVector<SDValue, 8> Ops;
   3069     for (unsigned i = 0; i != NumElems; ++i) {
   3070       if (Mask[i] < 0) {
   3071         Ops.push_back(DAG.getUNDEF(EltVT));
   3072         continue;
   3073       }
   3074       unsigned Idx = Mask[i];
   3075       if (Idx < NumElems)
   3076         Ops.push_back(DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, EltVT,
   3077                                   Node->getOperand(0),
   3078                                   DAG.getIntPtrConstant(Idx)));
   3079       else
   3080         Ops.push_back(DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, EltVT,
   3081                                   Node->getOperand(1),
   3082                                   DAG.getIntPtrConstant(Idx - NumElems)));
   3083     }
   3084     Tmp1 = DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &Ops[0], Ops.size());
   3085     Results.push_back(Tmp1);
   3086     break;
   3087   }
   3088   case ISD::EXTRACT_ELEMENT: {
   3089     EVT OpTy = Node->getOperand(0).getValueType();
   3090     if (cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue()) {
   3091       // 1 -> Hi
   3092       Tmp1 = DAG.getNode(ISD::SRL, dl, OpTy, Node->getOperand(0),
   3093                          DAG.getConstant(OpTy.getSizeInBits()/2,
   3094                     TLI.getShiftAmountTy(Node->getOperand(0).getValueType())));
   3095       Tmp1 = DAG.getNode(ISD::TRUNCATE, dl, Node->getValueType(0), Tmp1);
   3096     } else {
   3097       // 0 -> Lo
   3098       Tmp1 = DAG.getNode(ISD::TRUNCATE, dl, Node->getValueType(0),
   3099                          Node->getOperand(0));
   3100     }
   3101     Results.push_back(Tmp1);
   3102     break;
   3103   }
   3104   case ISD::STACKSAVE:
   3105     // Expand to CopyFromReg if the target set
   3106     // StackPointerRegisterToSaveRestore.
   3107     if (unsigned SP = TLI.getStackPointerRegisterToSaveRestore()) {
   3108       Results.push_back(DAG.getCopyFromReg(Node->getOperand(0), dl, SP,
   3109                                            Node->getValueType(0)));
   3110       Results.push_back(Results[0].getValue(1));
   3111     } else {
   3112       Results.push_back(DAG.getUNDEF(Node->getValueType(0)));
   3113       Results.push_back(Node->getOperand(0));
   3114     }
   3115     break;
   3116   case ISD::STACKRESTORE:
   3117     // Expand to CopyToReg if the target set
   3118     // StackPointerRegisterToSaveRestore.
   3119     if (unsigned SP = TLI.getStackPointerRegisterToSaveRestore()) {
   3120       Results.push_back(DAG.getCopyToReg(Node->getOperand(0), dl, SP,
   3121                                          Node->getOperand(1)));
   3122     } else {
   3123       Results.push_back(Node->getOperand(0));
   3124     }
   3125     break;
   3126   case ISD::FCOPYSIGN:
   3127     Results.push_back(ExpandFCOPYSIGN(Node));
   3128     break;
   3129   case ISD::FNEG:
   3130     // Expand Y = FNEG(X) ->  Y = SUB -0.0, X
   3131     Tmp1 = DAG.getConstantFP(-0.0, Node->getValueType(0));
   3132     Tmp1 = DAG.getNode(ISD::FSUB, dl, Node->getValueType(0), Tmp1,
   3133                        Node->getOperand(0));
   3134     Results.push_back(Tmp1);
   3135     break;
   3136   case ISD::FABS: {
   3137     // Expand Y = FABS(X) -> Y = (X >u 0.0) ? X : fneg(X).
   3138     EVT VT = Node->getValueType(0);
   3139     Tmp1 = Node->getOperand(0);
   3140     Tmp2 = DAG.getConstantFP(0.0, VT);
   3141     Tmp2 = DAG.getSetCC(dl, TLI.getSetCCResultType(Tmp1.getValueType()),
   3142                         Tmp1, Tmp2, ISD::SETUGT);
   3143     Tmp3 = DAG.getNode(ISD::FNEG, dl, VT, Tmp1);
   3144     Tmp1 = DAG.getNode(ISD::SELECT, dl, VT, Tmp2, Tmp1, Tmp3);
   3145     Results.push_back(Tmp1);
   3146     break;
   3147   }
   3148   case ISD::FSQRT:
   3149     Results.push_back(ExpandFPLibCall(Node, RTLIB::SQRT_F32, RTLIB::SQRT_F64,
   3150                                       RTLIB::SQRT_F80, RTLIB::SQRT_PPCF128));
   3151     break;
   3152   case ISD::FSIN:
   3153     Results.push_back(ExpandFPLibCall(Node, RTLIB::SIN_F32, RTLIB::SIN_F64,
   3154                                       RTLIB::SIN_F80, RTLIB::SIN_PPCF128));
   3155     break;
   3156   case ISD::FCOS:
   3157     Results.push_back(ExpandFPLibCall(Node, RTLIB::COS_F32, RTLIB::COS_F64,
   3158                                       RTLIB::COS_F80, RTLIB::COS_PPCF128));
   3159     break;
   3160   case ISD::FLOG:
   3161     Results.push_back(ExpandFPLibCall(Node, RTLIB::LOG_F32, RTLIB::LOG_F64,
   3162                                       RTLIB::LOG_F80, RTLIB::LOG_PPCF128));
   3163     break;
   3164   case ISD::FLOG2:
   3165     Results.push_back(ExpandFPLibCall(Node, RTLIB::LOG2_F32, RTLIB::LOG2_F64,
   3166                                       RTLIB::LOG2_F80, RTLIB::LOG2_PPCF128));
   3167     break;
   3168   case ISD::FLOG10:
   3169     Results.push_back(ExpandFPLibCall(Node, RTLIB::LOG10_F32, RTLIB::LOG10_F64,
   3170                                       RTLIB::LOG10_F80, RTLIB::LOG10_PPCF128));
   3171     break;
   3172   case ISD::FEXP:
   3173     Results.push_back(ExpandFPLibCall(Node, RTLIB::EXP_F32, RTLIB::EXP_F64,
   3174                                       RTLIB::EXP_F80, RTLIB::EXP_PPCF128));
   3175     break;
   3176   case ISD::FEXP2:
   3177     Results.push_back(ExpandFPLibCall(Node, RTLIB::EXP2_F32, RTLIB::EXP2_F64,
   3178                                       RTLIB::EXP2_F80, RTLIB::EXP2_PPCF128));
   3179     break;
   3180   case ISD::FTRUNC:
   3181     Results.push_back(ExpandFPLibCall(Node, RTLIB::TRUNC_F32, RTLIB::TRUNC_F64,
   3182                                       RTLIB::TRUNC_F80, RTLIB::TRUNC_PPCF128));
   3183     break;
   3184   case ISD::FFLOOR:
   3185     Results.push_back(ExpandFPLibCall(Node, RTLIB::FLOOR_F32, RTLIB::FLOOR_F64,
   3186                                       RTLIB::FLOOR_F80, RTLIB::FLOOR_PPCF128));
   3187     break;
   3188   case ISD::FCEIL:
   3189     Results.push_back(ExpandFPLibCall(Node, RTLIB::CEIL_F32, RTLIB::CEIL_F64,
   3190                                       RTLIB::CEIL_F80, RTLIB::CEIL_PPCF128));
   3191     break;
   3192   case ISD::FRINT:
   3193     Results.push_back(ExpandFPLibCall(Node, RTLIB::RINT_F32, RTLIB::RINT_F64,
   3194                                       RTLIB::RINT_F80, RTLIB::RINT_PPCF128));
   3195     break;
   3196   case ISD::FNEARBYINT:
   3197     Results.push_back(ExpandFPLibCall(Node, RTLIB::NEARBYINT_F32,
   3198                                       RTLIB::NEARBYINT_F64,
   3199                                       RTLIB::NEARBYINT_F80,
   3200                                       RTLIB::NEARBYINT_PPCF128));
   3201     break;
   3202   case ISD::FPOWI:
   3203     Results.push_back(ExpandFPLibCall(Node, RTLIB::POWI_F32, RTLIB::POWI_F64,
   3204                                       RTLIB::POWI_F80, RTLIB::POWI_PPCF128));
   3205     break;
   3206   case ISD::FPOW:
   3207     Results.push_back(ExpandFPLibCall(Node, RTLIB::POW_F32, RTLIB::POW_F64,
   3208                                       RTLIB::POW_F80, RTLIB::POW_PPCF128));
   3209     break;
   3210   case ISD::FDIV:
   3211     Results.push_back(ExpandFPLibCall(Node, RTLIB::DIV_F32, RTLIB::DIV_F64,
   3212                                       RTLIB::DIV_F80, RTLIB::DIV_PPCF128));
   3213     break;
   3214   case ISD::FREM:
   3215     Results.push_back(ExpandFPLibCall(Node, RTLIB::REM_F32, RTLIB::REM_F64,
   3216                                       RTLIB::REM_F80, RTLIB::REM_PPCF128));
   3217     break;
   3218   case ISD::FMA:
   3219     Results.push_back(ExpandFPLibCall(Node, RTLIB::FMA_F32, RTLIB::FMA_F64,
   3220                                       RTLIB::FMA_F80, RTLIB::FMA_PPCF128));
   3221     break;
   3222   case ISD::FP16_TO_FP32:
   3223     Results.push_back(ExpandLibCall(RTLIB::FPEXT_F16_F32, Node, false));
   3224     break;
   3225   case ISD::FP32_TO_FP16:
   3226     Results.push_back(ExpandLibCall(RTLIB::FPROUND_F32_F16, Node, false));
   3227     break;
   3228   case ISD::ConstantFP: {
   3229     ConstantFPSDNode *CFP = cast<ConstantFPSDNode>(Node);
   3230     // Check to see if this FP immediate is already legal.
   3231     // If this is a legal constant, turn it into a TargetConstantFP node.
   3232     if (TLI.isFPImmLegal(CFP->getValueAPF(), Node->getValueType(0)))
   3233       Results.push_back(SDValue(Node, 0));
   3234     else
   3235       Results.push_back(ExpandConstantFP(CFP, true, DAG, TLI));
   3236     break;
   3237   }
   3238   case ISD::EHSELECTION: {
   3239     unsigned Reg = TLI.getExceptionSelectorRegister();
   3240     assert(Reg && "Can't expand to unknown register!");
   3241     Results.push_back(DAG.getCopyFromReg(Node->getOperand(1), dl, Reg,
   3242                                          Node->getValueType(0)));
   3243     Results.push_back(Results[0].getValue(1));
   3244     break;
   3245   }
   3246   case ISD::EXCEPTIONADDR: {
   3247     unsigned Reg = TLI.getExceptionAddressRegister();
   3248     assert(Reg && "Can't expand to unknown register!");
   3249     Results.push_back(DAG.getCopyFromReg(Node->getOperand(0), dl, Reg,
   3250                                          Node->getValueType(0)));
   3251     Results.push_back(Results[0].getValue(1));
   3252     break;
   3253   }
   3254   case ISD::SUB: {
   3255     EVT VT = Node->getValueType(0);
   3256     assert(TLI.isOperationLegalOrCustom(ISD::ADD, VT) &&
   3257            TLI.isOperationLegalOrCustom(ISD::XOR, VT) &&
   3258            "Don't know how to expand this subtraction!");
   3259     Tmp1 = DAG.getNode(ISD::XOR, dl, VT, Node->getOperand(1),
   3260                DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), VT));
   3261     Tmp1 = DAG.getNode(ISD::ADD, dl, VT, Tmp2, DAG.getConstant(1, VT));
   3262     Results.push_back(DAG.getNode(ISD::ADD, dl, VT, Node->getOperand(0), Tmp1));
   3263     break;
   3264   }
   3265   case ISD::UREM:
   3266   case ISD::SREM: {
   3267     EVT VT = Node->getValueType(0);
   3268     SDVTList VTs = DAG.getVTList(VT, VT);
   3269     bool isSigned = Node->getOpcode() == ISD::SREM;
   3270     unsigned DivOpc = isSigned ? ISD::SDIV : ISD::UDIV;
   3271     unsigned DivRemOpc = isSigned ? ISD::SDIVREM : ISD::UDIVREM;
   3272     Tmp2 = Node->getOperand(0);
   3273     Tmp3 = Node->getOperand(1);
   3274     if (TLI.isOperationLegalOrCustom(DivRemOpc, VT) ||
   3275         (isDivRemLibcallAvailable(Node, isSigned, TLI) &&
   3276          UseDivRem(Node, isSigned, false))) {
   3277       Tmp1 = DAG.getNode(DivRemOpc, dl, VTs, Tmp2, Tmp3).getValue(1);
   3278     } else if (TLI.isOperationLegalOrCustom(DivOpc, VT)) {
   3279       // X % Y -> X-X/Y*Y
   3280       Tmp1 = DAG.getNode(DivOpc, dl, VT, Tmp2, Tmp3);
   3281       Tmp1 = DAG.getNode(ISD::MUL, dl, VT, Tmp1, Tmp3);
   3282       Tmp1 = DAG.getNode(ISD::SUB, dl, VT, Tmp2, Tmp1);
   3283     } else if (isSigned)
   3284       Tmp1 = ExpandIntLibCall(Node, true,
   3285                               RTLIB::SREM_I8,
   3286                               RTLIB::SREM_I16, RTLIB::SREM_I32,
   3287                               RTLIB::SREM_I64, RTLIB::SREM_I128);
   3288     else
   3289       Tmp1 = ExpandIntLibCall(Node, false,
   3290                               RTLIB::UREM_I8,
   3291                               RTLIB::UREM_I16, RTLIB::UREM_I32,
   3292                               RTLIB::UREM_I64, RTLIB::UREM_I128);
   3293     Results.push_back(Tmp1);
   3294     break;
   3295   }
   3296   case ISD::UDIV:
   3297   case ISD::SDIV: {
   3298     bool isSigned = Node->getOpcode() == ISD::SDIV;
   3299     unsigned DivRemOpc = isSigned ? ISD::SDIVREM : ISD::UDIVREM;
   3300     EVT VT = Node->getValueType(0);
   3301     SDVTList VTs = DAG.getVTList(VT, VT);
   3302     if (TLI.isOperationLegalOrCustom(DivRemOpc, VT) ||
   3303         (isDivRemLibcallAvailable(Node, isSigned, TLI) &&
   3304          UseDivRem(Node, isSigned, true)))
   3305       Tmp1 = DAG.getNode(DivRemOpc, dl, VTs, Node->getOperand(0),
   3306                          Node->getOperand(1));
   3307     else if (isSigned)
   3308       Tmp1 = ExpandIntLibCall(Node, true,
   3309                               RTLIB::SDIV_I8,
   3310                               RTLIB::SDIV_I16, RTLIB::SDIV_I32,
   3311                               RTLIB::SDIV_I64, RTLIB::SDIV_I128);
   3312     else
   3313       Tmp1 = ExpandIntLibCall(Node, false,
   3314                               RTLIB::UDIV_I8,
   3315                               RTLIB::UDIV_I16, RTLIB::UDIV_I32,
   3316                               RTLIB::UDIV_I64, RTLIB::UDIV_I128);
   3317     Results.push_back(Tmp1);
   3318     break;
   3319   }
   3320   case ISD::MULHU:
   3321   case ISD::MULHS: {
   3322     unsigned ExpandOpcode = Node->getOpcode() == ISD::MULHU ? ISD::UMUL_LOHI :
   3323                                                               ISD::SMUL_LOHI;
   3324     EVT VT = Node->getValueType(0);
   3325     SDVTList VTs = DAG.getVTList(VT, VT);
   3326     assert(TLI.isOperationLegalOrCustom(ExpandOpcode, VT) &&
   3327            "If this wasn't legal, it shouldn't have been created!");
   3328     Tmp1 = DAG.getNode(ExpandOpcode, dl, VTs, Node->getOperand(0),
   3329                        Node->getOperand(1));
   3330     Results.push_back(Tmp1.getValue(1));
   3331     break;
   3332   }
   3333   case ISD::SDIVREM:
   3334   case ISD::UDIVREM:
   3335     // Expand into divrem libcall
   3336     ExpandDivRemLibCall(Node, Results);
   3337     break;
   3338   case ISD::MUL: {
   3339     EVT VT = Node->getValueType(0);
   3340     SDVTList VTs = DAG.getVTList(VT, VT);
   3341     // See if multiply or divide can be lowered using two-result operations.
   3342     // We just need the low half of the multiply; try both the signed
   3343     // and unsigned forms. If the target supports both SMUL_LOHI and
   3344     // UMUL_LOHI, form a preference by checking which forms of plain
   3345     // MULH it supports.
   3346     bool HasSMUL_LOHI = TLI.isOperationLegalOrCustom(ISD::SMUL_LOHI, VT);
   3347     bool HasUMUL_LOHI = TLI.isOperationLegalOrCustom(ISD::UMUL_LOHI, VT);
   3348     bool HasMULHS = TLI.isOperationLegalOrCustom(ISD::MULHS, VT);
   3349     bool HasMULHU = TLI.isOperationLegalOrCustom(ISD::MULHU, VT);
   3350     unsigned OpToUse = 0;
   3351     if (HasSMUL_LOHI && !HasMULHS) {
   3352       OpToUse = ISD::SMUL_LOHI;
   3353     } else if (HasUMUL_LOHI && !HasMULHU) {
   3354       OpToUse = ISD::UMUL_LOHI;
   3355     } else if (HasSMUL_LOHI) {
   3356       OpToUse = ISD::SMUL_LOHI;
   3357     } else if (HasUMUL_LOHI) {
   3358       OpToUse = ISD::UMUL_LOHI;
   3359     }
   3360     if (OpToUse) {
   3361       Results.push_back(DAG.getNode(OpToUse, dl, VTs, Node->getOperand(0),
   3362                                     Node->getOperand(1)));
   3363       break;
   3364     }
   3365     Tmp1 = ExpandIntLibCall(Node, false,
   3366                             RTLIB::MUL_I8,
   3367                             RTLIB::MUL_I16, RTLIB::MUL_I32,
   3368                             RTLIB::MUL_I64, RTLIB::MUL_I128);
   3369     Results.push_back(Tmp1);
   3370     break;
   3371   }
   3372   case ISD::SADDO:
   3373   case ISD::SSUBO: {
   3374     SDValue LHS = Node->getOperand(0);
   3375     SDValue RHS = Node->getOperand(1);
   3376     SDValue Sum = DAG.getNode(Node->getOpcode() == ISD::SADDO ?
   3377                               ISD::ADD : ISD::SUB, dl, LHS.getValueType(),
   3378                               LHS, RHS);
   3379     Results.push_back(Sum);
   3380     EVT OType = Node->getValueType(1);
   3381 
   3382     SDValue Zero = DAG.getConstant(0, LHS.getValueType());
   3383 
   3384     //   LHSSign -> LHS >= 0
   3385     //   RHSSign -> RHS >= 0
   3386     //   SumSign -> Sum >= 0
   3387     //
   3388     //   Add:
   3389     //   Overflow -> (LHSSign == RHSSign) && (LHSSign != SumSign)
   3390     //   Sub:
   3391     //   Overflow -> (LHSSign != RHSSign) && (LHSSign != SumSign)
   3392     //
   3393     SDValue LHSSign = DAG.getSetCC(dl, OType, LHS, Zero, ISD::SETGE);
   3394     SDValue RHSSign = DAG.getSetCC(dl, OType, RHS, Zero, ISD::SETGE);
   3395     SDValue SignsMatch = DAG.getSetCC(dl, OType, LHSSign, RHSSign,
   3396                                       Node->getOpcode() == ISD::SADDO ?
   3397                                       ISD::SETEQ : ISD::SETNE);
   3398 
   3399     SDValue SumSign = DAG.getSetCC(dl, OType, Sum, Zero, ISD::SETGE);
   3400     SDValue SumSignNE = DAG.getSetCC(dl, OType, LHSSign, SumSign, ISD::SETNE);
   3401 
   3402     SDValue Cmp = DAG.getNode(ISD::AND, dl, OType, SignsMatch, SumSignNE);
   3403     Results.push_back(Cmp);
   3404     break;
   3405   }
   3406   case ISD::UADDO:
   3407   case ISD::USUBO: {
   3408     SDValue LHS = Node->getOperand(0);
   3409     SDValue RHS = Node->getOperand(1);
   3410     SDValue Sum = DAG.getNode(Node->getOpcode() == ISD::UADDO ?
   3411                               ISD::ADD : ISD::SUB, dl, LHS.getValueType(),
   3412                               LHS, RHS);
   3413     Results.push_back(Sum);
   3414     Results.push_back(DAG.getSetCC(dl, Node->getValueType(1), Sum, LHS,
   3415                                    Node->getOpcode () == ISD::UADDO ?
   3416                                    ISD::SETULT : ISD::SETUGT));
   3417     break;
   3418   }
   3419   case ISD::UMULO:
   3420   case ISD::SMULO: {
   3421     EVT VT = Node->getValueType(0);
   3422     EVT WideVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits() * 2);
   3423     SDValue LHS = Node->getOperand(0);
   3424     SDValue RHS = Node->getOperand(1);
   3425     SDValue BottomHalf;
   3426     SDValue TopHalf;
   3427     static const unsigned Ops[2][3] =
   3428         { { ISD::MULHU, ISD::UMUL_LOHI, ISD::ZERO_EXTEND },
   3429           { ISD::MULHS, ISD::SMUL_LOHI, ISD::SIGN_EXTEND }};
   3430     bool isSigned = Node->getOpcode() == ISD::SMULO;
   3431     if (TLI.isOperationLegalOrCustom(Ops[isSigned][0], VT)) {
   3432       BottomHalf = DAG.getNode(ISD::MUL, dl, VT, LHS, RHS);
   3433       TopHalf = DAG.getNode(Ops[isSigned][0], dl, VT, LHS, RHS);
   3434     } else if (TLI.isOperationLegalOrCustom(Ops[isSigned][1], VT)) {
   3435       BottomHalf = DAG.getNode(Ops[isSigned][1], dl, DAG.getVTList(VT, VT), LHS,
   3436                                RHS);
   3437       TopHalf = BottomHalf.getValue(1);
   3438     } else if (TLI.isTypeLegal(EVT::getIntegerVT(*DAG.getContext(),
   3439                                                  VT.getSizeInBits() * 2))) {
   3440       LHS = DAG.getNode(Ops[isSigned][2], dl, WideVT, LHS);
   3441       RHS = DAG.getNode(Ops[isSigned][2], dl, WideVT, RHS);
   3442       Tmp1 = DAG.getNode(ISD::MUL, dl, WideVT, LHS, RHS);
   3443       BottomHalf = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, VT, Tmp1,
   3444                                DAG.getIntPtrConstant(0));
   3445       TopHalf = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, VT, Tmp1,
   3446                             DAG.getIntPtrConstant(1));
   3447     } else {
   3448       // We can fall back to a libcall with an illegal type for the MUL if we
   3449       // have a libcall big enough.
   3450       // Also, we can fall back to a division in some cases, but that's a big
   3451       // performance hit in the general case.
   3452       RTLIB::Libcall LC = RTLIB::UNKNOWN_LIBCALL;
   3453       if (WideVT == MVT::i16)
   3454         LC = RTLIB::MUL_I16;
   3455       else if (WideVT == MVT::i32)
   3456         LC = RTLIB::MUL_I32;
   3457       else if (WideVT == MVT::i64)
   3458         LC = RTLIB::MUL_I64;
   3459       else if (WideVT == MVT::i128)
   3460         LC = RTLIB::MUL_I128;
   3461       assert(LC != RTLIB::UNKNOWN_LIBCALL && "Cannot expand this operation!");
   3462 
   3463       // The high part is obtained by SRA'ing all but one of the bits of low
   3464       // part.
   3465       unsigned LoSize = VT.getSizeInBits();
   3466       SDValue HiLHS = DAG.getNode(ISD::SRA, dl, VT, RHS,
   3467                                 DAG.getConstant(LoSize-1, TLI.getPointerTy()));
   3468       SDValue HiRHS = DAG.getNode(ISD::SRA, dl, VT, LHS,
   3469                                 DAG.getConstant(LoSize-1, TLI.getPointerTy()));
   3470 
   3471       // Here we're passing the 2 arguments explicitly as 4 arguments that are
   3472       // pre-lowered to the correct types. This all depends upon WideVT not
   3473       // being a legal type for the architecture and thus has to be split to
   3474       // two arguments.
   3475       SDValue Args[] = { LHS, HiLHS, RHS, HiRHS };
   3476       SDValue Ret = ExpandLibCall(LC, WideVT, Args, 4, isSigned, dl);
   3477       BottomHalf = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, VT, Ret,
   3478                                DAG.getIntPtrConstant(0));
   3479       TopHalf = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, VT, Ret,
   3480                             DAG.getIntPtrConstant(1));
   3481     }
   3482 
   3483     if (isSigned) {
   3484       Tmp1 = DAG.getConstant(VT.getSizeInBits() - 1,
   3485                              TLI.getShiftAmountTy(BottomHalf.getValueType()));
   3486       Tmp1 = DAG.getNode(ISD::SRA, dl, VT, BottomHalf, Tmp1);
   3487       TopHalf = DAG.getSetCC(dl, TLI.getSetCCResultType(VT), TopHalf, Tmp1,
   3488                              ISD::SETNE);
   3489     } else {
   3490       TopHalf = DAG.getSetCC(dl, TLI.getSetCCResultType(VT), TopHalf,
   3491                              DAG.getConstant(0, VT), ISD::SETNE);
   3492     }
   3493     Results.push_back(BottomHalf);
   3494     Results.push_back(TopHalf);
   3495     break;
   3496   }
   3497   case ISD::BUILD_PAIR: {
   3498     EVT PairTy = Node->getValueType(0);
   3499     Tmp1 = DAG.getNode(ISD::ZERO_EXTEND, dl, PairTy, Node->getOperand(0));
   3500     Tmp2 = DAG.getNode(ISD::ANY_EXTEND, dl, PairTy, Node->getOperand(1));
   3501     Tmp2 = DAG.getNode(ISD::SHL, dl, PairTy, Tmp2,
   3502                        DAG.getConstant(PairTy.getSizeInBits()/2,
   3503                                        TLI.getShiftAmountTy(PairTy)));
   3504     Results.push_back(DAG.getNode(ISD::OR, dl, PairTy, Tmp1, Tmp2));
   3505     break;
   3506   }
   3507   case ISD::SELECT:
   3508     Tmp1 = Node->getOperand(0);
   3509     Tmp2 = Node->getOperand(1);
   3510     Tmp3 = Node->getOperand(2);
   3511     if (Tmp1.getOpcode() == ISD::SETCC) {
   3512       Tmp1 = DAG.getSelectCC(dl, Tmp1.getOperand(0), Tmp1.getOperand(1),
   3513                              Tmp2, Tmp3,
   3514                              cast<CondCodeSDNode>(Tmp1.getOperand(2))->get());
   3515     } else {
   3516       Tmp1 = DAG.getSelectCC(dl, Tmp1,
   3517                              DAG.getConstant(0, Tmp1.getValueType()),
   3518                              Tmp2, Tmp3, ISD::SETNE);
   3519     }
   3520     Results.push_back(Tmp1);
   3521     break;
   3522   case ISD::BR_JT: {
   3523     SDValue Chain = Node->getOperand(0);
   3524     SDValue Table = Node->getOperand(1);
   3525     SDValue Index = Node->getOperand(2);
   3526 
   3527     EVT PTy = TLI.getPointerTy();
   3528 
   3529     const TargetData &TD = *TLI.getTargetData();
   3530     unsigned EntrySize =
   3531       DAG.getMachineFunction().getJumpTableInfo()->getEntrySize(TD);
   3532 
   3533     Index = DAG.getNode(ISD::MUL, dl, PTy,
   3534                         Index, DAG.getConstant(EntrySize, PTy));
   3535     SDValue Addr = DAG.getNode(ISD::ADD, dl, PTy, Index, Table);
   3536 
   3537     EVT MemVT = EVT::getIntegerVT(*DAG.getContext(), EntrySize * 8);
   3538     SDValue LD = DAG.getExtLoad(ISD::SEXTLOAD, dl, PTy, Chain, Addr,
   3539                                 MachinePointerInfo::getJumpTable(), MemVT,
   3540                                 false, false, 0);
   3541     Addr = LD;
   3542     if (TM.getRelocationModel() == Reloc::PIC_) {
   3543       // For PIC, the sequence is:
   3544       // BRIND(load(Jumptable + index) + RelocBase)
   3545       // RelocBase can be JumpTable, GOT or some sort of global base.
   3546       Addr = DAG.getNode(ISD::ADD, dl, PTy, Addr,
   3547                           TLI.getPICJumpTableRelocBase(Table, DAG));
   3548     }
   3549     Tmp1 = DAG.getNode(ISD::BRIND, dl, MVT::Other, LD.getValue(1), Addr);
   3550     Results.push_back(Tmp1);
   3551     break;
   3552   }
   3553   case ISD::BRCOND:
   3554     // Expand brcond's setcc into its constituent parts and create a BR_CC
   3555     // Node.
   3556     Tmp1 = Node->getOperand(0);
   3557     Tmp2 = Node->getOperand(1);
   3558     if (Tmp2.getOpcode() == ISD::SETCC) {
   3559       Tmp1 = DAG.getNode(ISD::BR_CC, dl, MVT::Other,
   3560                          Tmp1, Tmp2.getOperand(2),
   3561                          Tmp2.getOperand(0), Tmp2.getOperand(1),
   3562                          Node->getOperand(2));
   3563     } else {
   3564       // We test only the i1 bit.  Skip the AND if UNDEF.
   3565       Tmp3 = (Tmp2.getOpcode() == ISD::UNDEF) ? Tmp2 :
   3566         DAG.getNode(ISD::AND, dl, Tmp2.getValueType(), Tmp2,
   3567                     DAG.getConstant(1, Tmp2.getValueType()));
   3568       Tmp1 = DAG.getNode(ISD::BR_CC, dl, MVT::Other, Tmp1,
   3569                          DAG.getCondCode(ISD::SETNE), Tmp3,
   3570                          DAG.getConstant(0, Tmp3.getValueType()),
   3571                          Node->getOperand(2));
   3572     }
   3573     Results.push_back(Tmp1);
   3574     break;
   3575   case ISD::SETCC: {
   3576     Tmp1 = Node->getOperand(0);
   3577     Tmp2 = Node->getOperand(1);
   3578     Tmp3 = Node->getOperand(2);
   3579     LegalizeSetCCCondCode(Node->getValueType(0), Tmp1, Tmp2, Tmp3, dl);
   3580 
   3581     // If we expanded the SETCC into an AND/OR, return the new node
   3582     if (Tmp2.getNode() == 0) {
   3583       Results.push_back(Tmp1);
   3584       break;
   3585     }
   3586 
   3587     // Otherwise, SETCC for the given comparison type must be completely
   3588     // illegal; expand it into a SELECT_CC.
   3589     EVT VT = Node->getValueType(0);
   3590     Tmp1 = DAG.getNode(ISD::SELECT_CC, dl, VT, Tmp1, Tmp2,
   3591                        DAG.getConstant(1, VT), DAG.getConstant(0, VT), Tmp3);
   3592     Results.push_back(Tmp1);
   3593     break;
   3594   }
   3595   case ISD::SELECT_CC: {
   3596     Tmp1 = Node->getOperand(0);   // LHS
   3597     Tmp2 = Node->getOperand(1);   // RHS
   3598     Tmp3 = Node->getOperand(2);   // True
   3599     Tmp4 = Node->getOperand(3);   // False
   3600     SDValue CC = Node->getOperand(4);
   3601 
   3602     LegalizeSetCCCondCode(TLI.getSetCCResultType(Tmp1.getValueType()),
   3603                           Tmp1, Tmp2, CC, dl);
   3604 
   3605     assert(!Tmp2.getNode() && "Can't legalize SELECT_CC with legal condition!");
   3606     Tmp2 = DAG.getConstant(0, Tmp1.getValueType());
   3607     CC = DAG.getCondCode(ISD::SETNE);
   3608     Tmp1 = DAG.getNode(ISD::SELECT_CC, dl, Node->getValueType(0), Tmp1, Tmp2,
   3609                        Tmp3, Tmp4, CC);
   3610     Results.push_back(Tmp1);
   3611     break;
   3612   }
   3613   case ISD::BR_CC: {
   3614     Tmp1 = Node->getOperand(0);              // Chain
   3615     Tmp2 = Node->getOperand(2);              // LHS
   3616     Tmp3 = Node->getOperand(3);              // RHS
   3617     Tmp4 = Node->getOperand(1);              // CC
   3618 
   3619     LegalizeSetCCCondCode(TLI.getSetCCResultType(Tmp2.getValueType()),
   3620                           Tmp2, Tmp3, Tmp4, dl);
   3621     LastCALLSEQ_END = DAG.getEntryNode();
   3622 
   3623     assert(!Tmp3.getNode() && "Can't legalize BR_CC with legal condition!");
   3624     Tmp3 = DAG.getConstant(0, Tmp2.getValueType());
   3625     Tmp4 = DAG.getCondCode(ISD::SETNE);
   3626     Tmp1 = DAG.getNode(ISD::BR_CC, dl, Node->getValueType(0), Tmp1, Tmp4, Tmp2,
   3627                        Tmp3, Node->getOperand(4));
   3628     Results.push_back(Tmp1);
   3629     break;
   3630   }
   3631   case ISD::GLOBAL_OFFSET_TABLE:
   3632   case ISD::GlobalAddress:
   3633   case ISD::GlobalTLSAddress:
   3634   case ISD::ExternalSymbol:
   3635   case ISD::ConstantPool:
   3636   case ISD::JumpTable:
   3637   case ISD::INTRINSIC_W_CHAIN:
   3638   case ISD::INTRINSIC_WO_CHAIN:
   3639   case ISD::INTRINSIC_VOID:
   3640     // FIXME: Custom lowering for these operations shouldn't return null!
   3641     for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i)
   3642       Results.push_back(SDValue(Node, i));
   3643     break;
   3644   }
   3645 }
   3646 void SelectionDAGLegalize::PromoteNode(SDNode *Node,
   3647                                        SmallVectorImpl<SDValue> &Results) {
   3648   EVT OVT = Node->getValueType(0);
   3649   if (Node->getOpcode() == ISD::UINT_TO_FP ||
   3650       Node->getOpcode() == ISD::SINT_TO_FP ||
   3651       Node->getOpcode() == ISD::SETCC) {
   3652     OVT = Node->getOperand(0).getValueType();
   3653   }
   3654   EVT NVT = TLI.getTypeToPromoteTo(Node->getOpcode(), OVT);
   3655   DebugLoc dl = Node->getDebugLoc();
   3656   SDValue Tmp1, Tmp2, Tmp3;
   3657   switch (Node->getOpcode()) {
   3658   case ISD::CTTZ:
   3659   case ISD::CTLZ:
   3660   case ISD::CTPOP:
   3661     // Zero extend the argument.
   3662     Tmp1 = DAG.getNode(ISD::ZERO_EXTEND, dl, NVT, Node->getOperand(0));
   3663     // Perform the larger operation.
   3664     Tmp1 = DAG.getNode(Node->getOpcode(), dl, NVT, Tmp1);
   3665     if (Node->getOpcode() == ISD::CTTZ) {
   3666       //if Tmp1 == sizeinbits(NVT) then Tmp1 = sizeinbits(Old VT)
   3667       Tmp2 = DAG.getSetCC(dl, TLI.getSetCCResultType(NVT),
   3668                           Tmp1, DAG.getConstant(NVT.getSizeInBits(), NVT),
   3669                           ISD::SETEQ);
   3670       Tmp1 = DAG.getNode(ISD::SELECT, dl, NVT, Tmp2,
   3671                           DAG.getConstant(OVT.getSizeInBits(), NVT), Tmp1);
   3672     } else if (Node->getOpcode() == ISD::CTLZ) {
   3673       // Tmp1 = Tmp1 - (sizeinbits(NVT) - sizeinbits(Old VT))
   3674       Tmp1 = DAG.getNode(ISD::SUB, dl, NVT, Tmp1,
   3675                           DAG.getConstant(NVT.getSizeInBits() -
   3676                                           OVT.getSizeInBits(), NVT));
   3677     }
   3678     Results.push_back(DAG.getNode(ISD::TRUNCATE, dl, OVT, Tmp1));
   3679     break;
   3680   case ISD::BSWAP: {
   3681     unsigned DiffBits = NVT.getSizeInBits() - OVT.getSizeInBits();
   3682     Tmp1 = DAG.getNode(ISD::ZERO_EXTEND, dl, NVT, Node->getOperand(0));
   3683     Tmp1 = DAG.getNode(ISD::BSWAP, dl, NVT, Tmp1);
   3684     Tmp1 = DAG.getNode(ISD::SRL, dl, NVT, Tmp1,
   3685                           DAG.getConstant(DiffBits, TLI.getShiftAmountTy(NVT)));
   3686     Results.push_back(Tmp1);
   3687     break;
   3688   }
   3689   case ISD::FP_TO_UINT:
   3690   case ISD::FP_TO_SINT:
   3691     Tmp1 = PromoteLegalFP_TO_INT(Node->getOperand(0), Node->getValueType(0),
   3692                                  Node->getOpcode() == ISD::FP_TO_SINT, dl);
   3693     Results.push_back(Tmp1);
   3694     break;
   3695   case ISD::UINT_TO_FP:
   3696   case ISD::SINT_TO_FP:
   3697     Tmp1 = PromoteLegalINT_TO_FP(Node->getOperand(0), Node->getValueType(0),
   3698                                  Node->getOpcode() == ISD::SINT_TO_FP, dl);
   3699     Results.push_back(Tmp1);
   3700     break;
   3701   case ISD::AND:
   3702   case ISD::OR:
   3703   case ISD::XOR: {
   3704     unsigned ExtOp, TruncOp;
   3705     if (OVT.isVector()) {
   3706       ExtOp   = ISD::BITCAST;
   3707       TruncOp = ISD::BITCAST;
   3708     } else {
   3709       assert(OVT.isInteger() && "Cannot promote logic operation");
   3710       ExtOp   = ISD::ANY_EXTEND;
   3711       TruncOp = ISD::TRUNCATE;
   3712     }
   3713     // Promote each of the values to the new type.
   3714     Tmp1 = DAG.getNode(ExtOp, dl, NVT, Node->getOperand(0));
   3715     Tmp2 = DAG.getNode(ExtOp, dl, NVT, Node->getOperand(1));
   3716     // Perform the larger operation, then convert back
   3717     Tmp1 = DAG.getNode(Node->getOpcode(), dl, NVT, Tmp1, Tmp2);
   3718     Results.push_back(DAG.getNode(TruncOp, dl, OVT, Tmp1));
   3719     break;
   3720   }
   3721   case ISD::SELECT: {
   3722     unsigned ExtOp, TruncOp;
   3723     if (Node->getValueType(0).isVector()) {
   3724       ExtOp   = ISD::BITCAST;
   3725       TruncOp = ISD::BITCAST;
   3726     } else if (Node->getValueType(0).isInteger()) {
   3727       ExtOp   = ISD::ANY_EXTEND;
   3728       TruncOp = ISD::TRUNCATE;
   3729     } else {
   3730       ExtOp   = ISD::FP_EXTEND;
   3731       TruncOp = ISD::FP_ROUND;
   3732     }
   3733     Tmp1 = Node->getOperand(0);
   3734     // Promote each of the values to the new type.
   3735     Tmp2 = DAG.getNode(ExtOp, dl, NVT, Node->getOperand(1));
   3736     Tmp3 = DAG.getNode(ExtOp, dl, NVT, Node->getOperand(2));
   3737     // Perform the larger operation, then round down.
   3738     Tmp1 = DAG.getNode(ISD::SELECT, dl, NVT, Tmp1, Tmp2, Tmp3);
   3739     if (TruncOp != ISD::FP_ROUND)
   3740       Tmp1 = DAG.getNode(TruncOp, dl, Node->getValueType(0), Tmp1);
   3741     else
   3742       Tmp1 = DAG.getNode(TruncOp, dl, Node->getValueType(0), Tmp1,
   3743                          DAG.getIntPtrConstant(0));
   3744     Results.push_back(Tmp1);
   3745     break;
   3746   }
   3747   case ISD::VECTOR_SHUFFLE: {
   3748     SmallVector<int, 8> Mask;
   3749     cast<ShuffleVectorSDNode>(Node)->getMask(Mask);
   3750 
   3751     // Cast the two input vectors.
   3752     Tmp1 = DAG.getNode(ISD::BITCAST, dl, NVT, Node->getOperand(0));
   3753     Tmp2 = DAG.getNode(ISD::BITCAST, dl, NVT, Node->getOperand(1));
   3754 
   3755     // Convert the shuffle mask to the right # elements.
   3756     Tmp1 = ShuffleWithNarrowerEltType(NVT, OVT, dl, Tmp1, Tmp2, Mask);
   3757     Tmp1 = DAG.getNode(ISD::BITCAST, dl, OVT, Tmp1);
   3758     Results.push_back(Tmp1);
   3759     break;
   3760   }
   3761   case ISD::SETCC: {
   3762     unsigned ExtOp = ISD::FP_EXTEND;
   3763     if (NVT.isInteger()) {
   3764       ISD::CondCode CCCode =
   3765         cast<CondCodeSDNode>(Node->getOperand(2))->get();
   3766       ExtOp = isSignedIntSetCC(CCCode) ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
   3767     }
   3768     Tmp1 = DAG.getNode(ExtOp, dl, NVT, Node->getOperand(0));
   3769     Tmp2 = DAG.getNode(ExtOp, dl, NVT, Node->getOperand(1));
   3770     Results.push_back(DAG.getNode(ISD::SETCC, dl, Node->getValueType(0),
   3771                                   Tmp1, Tmp2, Node->getOperand(2)));
   3772     break;
   3773   }
   3774   }
   3775 }
   3776 
   3777 // SelectionDAG::Legalize - This is the entry point for the file.
   3778 //
   3779 void SelectionDAG::Legalize() {
   3780   /// run - This is the main entry point to this class.
   3781   ///
   3782   SelectionDAGLegalize(*this).LegalizeDAG();
   3783 }
   3784