lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp

   1 //===-------- LegalizeTypesGeneric.cpp - Generic type legalization --------===//
   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 generic type expansion and splitting for LegalizeTypes.
  11 // The routines here perform legalization when the details of the type (such as
  12 // whether it is an integer or a float) do not matter.
  13 // Expansion is the act of changing a computation in an illegal type to be a
  14 // computation in two identical registers of a smaller type.  The Lo/Hi part
  15 // is required to be stored first in memory on little/big-endian machines.
  16 // Splitting is the act of changing a computation in an illegal type to be a
  17 // computation in two not necessarily identical registers of a smaller type.
  18 // There are no requirements on how the type is represented in memory.
  19 //
  20 //===----------------------------------------------------------------------===//
  21
  22 #include "LegalizeTypes.h"
  23 #include "llvm/Target/TargetData.h"
  24 #include "llvm/CodeGen/PseudoSourceValue.h"
  25 using namespace llvm;
  26
  27 //===----------------------------------------------------------------------===//
  28 // Generic Result Expansion.
  29 //===----------------------------------------------------------------------===//
  30
  31 // These routines assume that the Lo/Hi part is stored first in memory on
  32 // little/big-endian machines, followed by the Hi/Lo part.  This means that
  33 // they cannot be used as is on vectors, for which Lo is always stored first.
  34
  35 void DAGTypeLegalizer::ExpandRes_BIT_CONVERT(SDNode *N, SDValue &Lo,
  36                                              SDValue &Hi) {
  37   EVT OutVT = N->getValueType(0);
  38   EVT NOutVT = TLI.getTypeToTransformTo(*DAG.getContext(), OutVT);
  39   SDValue InOp = N->getOperand(0);
  40   EVT InVT = InOp.getValueType();
  41   DebugLoc dl = N->getDebugLoc();
  42
  43   // Handle some special cases efficiently.
  44   switch (getTypeAction(InVT)) {
  45     default:
  46       assert(false && "Unknown type action!");
  47     case Legal:
  48     case PromoteInteger:
  49       break;
  50     case SoftenFloat:
  51       // Convert the integer operand instead.
  52       SplitInteger(GetSoftenedFloat(InOp), Lo, Hi);
  53       Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
  54       Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
  55       return;
  56     case ExpandInteger:
  57     case ExpandFloat:
  58       // Convert the expanded pieces of the input.
  59       GetExpandedOp(InOp, Lo, Hi);
  60       Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
  61       Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
  62       return;
  63     case SplitVector:
  64       GetSplitVector(InOp, Lo, Hi);
  65       if (TLI.isBigEndian())
  66         std::swap(Lo, Hi);
  67       Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
  68       Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
  69       return;
  70     case ScalarizeVector:
  71       // Convert the element instead.
  72       SplitInteger(BitConvertToInteger(GetScalarizedVector(InOp)), Lo, Hi);
  73       Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
  74       Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
  75       return;
  76     case WidenVector: {
  77       assert(!(InVT.getVectorNumElements() & 1) && "Unsupported BIT_CONVERT");
  78       InOp = GetWidenedVector(InOp);
  79       EVT InNVT = EVT::getVectorVT(*DAG.getContext(), InVT.getVectorElementType(),
  80                                    InVT.getVectorNumElements()/2);
  81       Lo = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
  82                        DAG.getIntPtrConstant(0));
  83       Hi = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, InNVT, InOp,
  84                        DAG.getIntPtrConstant(InNVT.getVectorNumElements()));
  85       if (TLI.isBigEndian())
  86         std::swap(Lo, Hi);
  87       Lo = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Lo);
  88       Hi = DAG.getNode(ISD::BIT_CONVERT, dl, NOutVT, Hi);
  89       return;
  90     }
  91   }
  92
  93   if (InVT.isVector() && OutVT.isInteger()) {
  94     // Handle cases like i64 = BIT_CONVERT v1i64 on x86, where the operand
  95     // is legal but the result is not.
  96     EVT NVT = EVT::getVectorVT(*DAG.getContext(), NOutVT, 2);
  97
  98     if (isTypeLegal(NVT)) {
  99       SDValue CastInOp = DAG.getNode(ISD::BIT_CONVERT, dl, NVT, InOp);
 100       Lo = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NOutVT, CastInOp,
 101                        DAG.getIntPtrConstant(0));
 102       Hi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NOutVT, CastInOp,
 103                        DAG.getIntPtrConstant(1));
 104
 105       if (TLI.isBigEndian())
 106         std::swap(Lo, Hi);
 107
 108       return;
 109     }
 110   }
 111
 112   // Lower the bit-convert to a store/load from the stack.
 113   assert(NOutVT.isByteSized() && "Expanded type not byte sized!");
 114
 115   // Create the stack frame object.  Make sure it is aligned for both
 116   // the source and expanded destination types.
 117   unsigned Alignment =
 118     TLI.getTargetData()->getPrefTypeAlignment(NOutVT.
 119                                               getTypeForEVT(*DAG.getContext()));
 120   SDValue StackPtr = DAG.CreateStackTemporary(InVT, Alignment);
 121   int SPFI = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
 122   MachinePointerInfo PtrInfo = MachinePointerInfo::getFixedStack(SPFI);
 123
 124   // Emit a store to the stack slot.
 125   SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, InOp, StackPtr, PtrInfo,
 126                                false, false, 0);
 127
 128   // Load the first half from the stack slot.
 129   Lo = DAG.getLoad(NOutVT, dl, Store, StackPtr, PtrInfo, false, false, 0);
 130
 131   // Increment the pointer to the other half.
 132   unsigned IncrementSize = NOutVT.getSizeInBits() / 8;
 133   StackPtr = DAG.getNode(ISD::ADD, dl, StackPtr.getValueType(), StackPtr,
 134                          DAG.getIntPtrConstant(IncrementSize));
 135
 136   // Load the second half from the stack slot.
 137   Hi = DAG.getLoad(NOutVT, dl, Store, StackPtr,
 138                    PtrInfo.getWithOffset(IncrementSize), false,
 139                    false, MinAlign(Alignment, IncrementSize));
 140
 141   // Handle endianness of the load.
 142   if (TLI.isBigEndian())
 143     std::swap(Lo, Hi);
 144 }
 145
 146 void DAGTypeLegalizer::ExpandRes_BUILD_PAIR(SDNode *N, SDValue &Lo,
 147                                             SDValue &Hi) {
 148   // Return the operands.
 149   Lo = N->getOperand(0);
 150   Hi = N->getOperand(1);
 151 }
 152
 153 void DAGTypeLegalizer::ExpandRes_EXTRACT_ELEMENT(SDNode *N, SDValue &Lo,
 154                                                  SDValue &Hi) {
 155   GetExpandedOp(N->getOperand(0), Lo, Hi);
 156   SDValue Part = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue() ?
 157                    Hi : Lo;
 158
 159   assert(Part.getValueType() == N->getValueType(0) &&
 160          "Type twice as big as expanded type not itself expanded!");
 161
 162   GetPairElements(Part, Lo, Hi);
 163 }
 164
 165 void DAGTypeLegalizer::ExpandRes_EXTRACT_VECTOR_ELT(SDNode *N, SDValue &Lo,
 166                                                     SDValue &Hi) {
 167   SDValue OldVec = N->getOperand(0);
 168   unsigned OldElts = OldVec.getValueType().getVectorNumElements();
 169   DebugLoc dl = N->getDebugLoc();
 170
 171   // Convert to a vector of the expanded element type, for example
 172   // <3 x i64> -> <6 x i32>.
 173   EVT OldVT = N->getValueType(0);
 174   EVT NewVT = TLI.getTypeToTransformTo(*DAG.getContext(), OldVT);
 175
 176   SDValue NewVec = DAG.getNode(ISD::BIT_CONVERT, dl,
 177                                EVT::getVectorVT(*DAG.getContext(),
 178                                                 NewVT, 2*OldElts),
 179                                OldVec);
 180
 181   // Extract the elements at 2 * Idx and 2 * Idx + 1 from the new vector.
 182   SDValue Idx = N->getOperand(1);
 183
 184   // Make sure the type of Idx is big enough to hold the new values.
 185   if (Idx.getValueType().bitsLT(TLI.getPointerTy()))
 186     Idx = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Idx);
 187
 188   Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, Idx);
 189   Lo = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NewVT, NewVec, Idx);
 190
 191   Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx,
 192                     DAG.getConstant(1, Idx.getValueType()));
 193   Hi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, NewVT, NewVec, Idx);
 194
 195   if (TLI.isBigEndian())
 196     std::swap(Lo, Hi);
 197 }
 198
 199 void DAGTypeLegalizer::ExpandRes_NormalLoad(SDNode *N, SDValue &Lo,
 200                                             SDValue &Hi) {
 201   assert(ISD::isNormalLoad(N) && "This routine only for normal loads!");
 202   DebugLoc dl = N->getDebugLoc();
 203
 204   LoadSDNode *LD = cast<LoadSDNode>(N);
 205   EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), LD->getValueType(0));
 206   SDValue Chain = LD->getChain();
 207   SDValue Ptr = LD->getBasePtr();
 208   unsigned Alignment = LD->getAlignment();
 209   bool isVolatile = LD->isVolatile();
 210   bool isNonTemporal = LD->isNonTemporal();
 211
 212   assert(NVT.isByteSized() && "Expanded type not byte sized!");
 213
 214   Lo = DAG.getLoad(NVT, dl, Chain, Ptr, LD->getPointerInfo(),
 215                    isVolatile, isNonTemporal, Alignment);
 216
 217   // Increment the pointer to the other half.
 218   unsigned IncrementSize = NVT.getSizeInBits() / 8;
 219   Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
 220                     DAG.getIntPtrConstant(IncrementSize));
 221   Hi = DAG.getLoad(NVT, dl, Chain, Ptr,
 222                    LD->getPointerInfo().getWithOffset(IncrementSize),
 223                    isVolatile, isNonTemporal,
 224                    MinAlign(Alignment, IncrementSize));
 225
 226   // Build a factor node to remember that this load is independent of the
 227   // other one.
 228   Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
 229                       Hi.getValue(1));
 230
 231   // Handle endianness of the load.
 232   if (TLI.isBigEndian())
 233     std::swap(Lo, Hi);
 234
 235   // Modified the chain - switch anything that used the old chain to use
 236   // the new one.
 237   ReplaceValueWith(SDValue(N, 1), Chain);
 238 }
 239
 240 void DAGTypeLegalizer::ExpandRes_VAARG(SDNode *N, SDValue &Lo, SDValue &Hi) {
 241   EVT OVT = N->getValueType(0);
 242   EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), OVT);
 243   SDValue Chain = N->getOperand(0);
 244   SDValue Ptr = N->getOperand(1);
 245   DebugLoc dl = N->getDebugLoc();
 246   const unsigned Align = N->getConstantOperandVal(3);
 247
 248   Lo = DAG.getVAArg(NVT, dl, Chain, Ptr, N->getOperand(2), Align);
 249   Hi = DAG.getVAArg(NVT, dl, Lo.getValue(1), Ptr, N->getOperand(2), 0);
 250
 251   // Handle endianness of the load.
 252   if (TLI.isBigEndian())
 253     std::swap(Lo, Hi);
 254
 255   // Modified the chain - switch anything that used the old chain to use
 256   // the new one.
 257   ReplaceValueWith(SDValue(N, 1), Hi.getValue(1));
 258 }
 259
 260
 261 //===--------------------------------------------------------------------===//
 262 // Generic Operand Expansion.
 263 //===--------------------------------------------------------------------===//
 264
 265 SDValue DAGTypeLegalizer::ExpandOp_BIT_CONVERT(SDNode *N) {
 266   DebugLoc dl = N->getDebugLoc();
 267   if (N->getValueType(0).isVector()) {
 268     // An illegal expanding type is being converted to a legal vector type.
 269     // Make a two element vector out of the expanded parts and convert that
 270     // instead, but only if the new vector type is legal (otherwise there
 271     // is no point, and it might create expansion loops).  For example, on
 272     // x86 this turns v1i64 = BIT_CONVERT i64 into v1i64 = BIT_CONVERT v2i32.
 273     EVT OVT = N->getOperand(0).getValueType();
 274     EVT NVT = EVT::getVectorVT(*DAG.getContext(),
 275                                TLI.getTypeToTransformTo(*DAG.getContext(), OVT),
 276                                2);
 277
 278     if (isTypeLegal(NVT)) {
 279       SDValue Parts[2];
 280       GetExpandedOp(N->getOperand(0), Parts[0], Parts[1]);
 281
 282       if (TLI.isBigEndian())
 283         std::swap(Parts[0], Parts[1]);
 284
 285       SDValue Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, NVT, Parts, 2);
 286       return DAG.getNode(ISD::BIT_CONVERT, dl, N->getValueType(0), Vec);
 287     }
 288   }
 289
 290   // Otherwise, store to a temporary and load out again as the new type.
 291   return CreateStackStoreLoad(N->getOperand(0), N->getValueType(0));
 292 }
 293
 294 SDValue DAGTypeLegalizer::ExpandOp_BUILD_VECTOR(SDNode *N) {
 295   // The vector type is legal but the element type needs expansion.
 296   EVT VecVT = N->getValueType(0);
 297   unsigned NumElts = VecVT.getVectorNumElements();
 298   EVT OldVT = N->getOperand(0).getValueType();
 299   EVT NewVT = TLI.getTypeToTransformTo(*DAG.getContext(), OldVT);
 300   DebugLoc dl = N->getDebugLoc();
 301
 302   assert(OldVT == VecVT.getVectorElementType() &&
 303          "BUILD_VECTOR operand type doesn't match vector element type!");
 304
 305   // Build a vector of twice the length out of the expanded elements.
 306   // For example <3 x i64> -> <6 x i32>.
 307   std::vector<SDValue> NewElts;
 308   NewElts.reserve(NumElts*2);
 309
 310   for (unsigned i = 0; i < NumElts; ++i) {
 311     SDValue Lo, Hi;
 312     GetExpandedOp(N->getOperand(i), Lo, Hi);
 313     if (TLI.isBigEndian())
 314       std::swap(Lo, Hi);
 315     NewElts.push_back(Lo);
 316     NewElts.push_back(Hi);
 317   }
 318
 319   SDValue NewVec = DAG.getNode(ISD::BUILD_VECTOR, dl,
 320                                EVT::getVectorVT(*DAG.getContext(),
 321                                                 NewVT, NewElts.size()),
 322                                &NewElts[0], NewElts.size());
 323
 324   // Convert the new vector to the old vector type.
 325   return DAG.getNode(ISD::BIT_CONVERT, dl, VecVT, NewVec);
 326 }
 327
 328 SDValue DAGTypeLegalizer::ExpandOp_EXTRACT_ELEMENT(SDNode *N) {
 329   SDValue Lo, Hi;
 330   GetExpandedOp(N->getOperand(0), Lo, Hi);
 331   return cast<ConstantSDNode>(N->getOperand(1))->getZExtValue() ? Hi : Lo;
 332 }
 333
 334 SDValue DAGTypeLegalizer::ExpandOp_INSERT_VECTOR_ELT(SDNode *N) {
 335   // The vector type is legal but the element type needs expansion.
 336   EVT VecVT = N->getValueType(0);
 337   unsigned NumElts = VecVT.getVectorNumElements();
 338   DebugLoc dl = N->getDebugLoc();
 339
 340   SDValue Val = N->getOperand(1);
 341   EVT OldEVT = Val.getValueType();
 342   EVT NewEVT = TLI.getTypeToTransformTo(*DAG.getContext(), OldEVT);
 343
 344   assert(OldEVT == VecVT.getVectorElementType() &&
 345          "Inserted element type doesn't match vector element type!");
 346
 347   // Bitconvert to a vector of twice the length with elements of the expanded
 348   // type, insert the expanded vector elements, and then convert back.
 349   EVT NewVecVT = EVT::getVectorVT(*DAG.getContext(), NewEVT, NumElts*2);
 350   SDValue NewVec = DAG.getNode(ISD::BIT_CONVERT, dl,
 351                                NewVecVT, N->getOperand(0));
 352
 353   SDValue Lo, Hi;
 354   GetExpandedOp(Val, Lo, Hi);
 355   if (TLI.isBigEndian())
 356     std::swap(Lo, Hi);
 357
 358   SDValue Idx = N->getOperand(2);
 359   Idx = DAG.getNode(ISD::ADD, dl, Idx.getValueType(), Idx, Idx);
 360   NewVec = DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, NewVecVT, NewVec, Lo, Idx);
 361   Idx = DAG.getNode(ISD::ADD, dl,
 362                     Idx.getValueType(), Idx, DAG.getIntPtrConstant(1));
 363   NewVec =  DAG.getNode(ISD::INSERT_VECTOR_ELT, dl, NewVecVT, NewVec, Hi, Idx);
 364
 365   // Convert the new vector to the old vector type.
 366   return DAG.getNode(ISD::BIT_CONVERT, dl, VecVT, NewVec);
 367 }
 368
 369 SDValue DAGTypeLegalizer::ExpandOp_SCALAR_TO_VECTOR(SDNode *N) {
 370   DebugLoc dl = N->getDebugLoc();
 371   EVT VT = N->getValueType(0);
 372   assert(VT.getVectorElementType() == N->getOperand(0).getValueType() &&
 373          "SCALAR_TO_VECTOR operand type doesn't match vector element type!");
 374   unsigned NumElts = VT.getVectorNumElements();
 375   SmallVector<SDValue, 16> Ops(NumElts);
 376   Ops[0] = N->getOperand(0);
 377   SDValue UndefVal = DAG.getUNDEF(Ops[0].getValueType());
 378   for (unsigned i = 1; i < NumElts; ++i)
 379     Ops[i] = UndefVal;
 380   return DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &Ops[0], NumElts);
 381 }
 382
 383 SDValue DAGTypeLegalizer::ExpandOp_NormalStore(SDNode *N, unsigned OpNo) {
 384   assert(ISD::isNormalStore(N) && "This routine only for normal stores!");
 385   assert(OpNo == 1 && "Can only expand the stored value so far");
 386   DebugLoc dl = N->getDebugLoc();
 387
 388   StoreSDNode *St = cast<StoreSDNode>(N);
 389   EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(),
 390                                      St->getValue().getValueType());
 391   SDValue Chain = St->getChain();
 392   SDValue Ptr = St->getBasePtr();
 393   unsigned Alignment = St->getAlignment();
 394   bool isVolatile = St->isVolatile();
 395   bool isNonTemporal = St->isNonTemporal();
 396
 397   assert(NVT.isByteSized() && "Expanded type not byte sized!");
 398   unsigned IncrementSize = NVT.getSizeInBits() / 8;
 399
 400   SDValue Lo, Hi;
 401   GetExpandedOp(St->getValue(), Lo, Hi);
 402
 403   if (TLI.isBigEndian())
 404     std::swap(Lo, Hi);
 405
 406   Lo = DAG.getStore(Chain, dl, Lo, Ptr, St->getPointerInfo(),
 407                     isVolatile, isNonTemporal, Alignment);
 408
 409   Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
 410                     DAG.getIntPtrConstant(IncrementSize));
 411   assert(isTypeLegal(Ptr.getValueType()) && "Pointers must be legal!");
 412   Hi = DAG.getStore(Chain, dl, Hi, Ptr,
 413                     St->getPointerInfo().getWithOffset(IncrementSize),
 414                     isVolatile, isNonTemporal,
 415                     MinAlign(Alignment, IncrementSize));
 416
 417   return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo, Hi);
 418 }
 419
 420
 421 //===--------------------------------------------------------------------===//
 422 // Generic Result Splitting.
 423 //===--------------------------------------------------------------------===//
 424
 425 // Be careful to make no assumptions about which of Lo/Hi is stored first in
 426 // memory (for vectors it is always Lo first followed by Hi in the following
 427 // bytes; for integers and floats it is Lo first if and only if the machine is
 428 // little-endian).
 429
 430 void DAGTypeLegalizer::SplitRes_MERGE_VALUES(SDNode *N,
 431                                              SDValue &Lo, SDValue &Hi) {
 432   // A MERGE_VALUES node can produce any number of values.  We know that the
 433   // first illegal one needs to be expanded into Lo/Hi.
 434   unsigned i;
 435
 436   // The string of legal results gets turned into input operands, which have
 437   // the same type.
 438   for (i = 0; isTypeLegal(N->getValueType(i)); ++i)
 439     ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
 440
 441   // The first illegal result must be the one that needs to be expanded.
 442   GetSplitOp(N->getOperand(i), Lo, Hi);
 443
 444   // Legalize the rest of the results into the input operands whether they are
 445   // legal or not.
 446   unsigned e = N->getNumValues();
 447   for (++i; i != e; ++i)
 448     ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
 449 }
 450
 451 void DAGTypeLegalizer::SplitRes_SELECT(SDNode *N, SDValue &Lo,
 452                                        SDValue &Hi) {
 453   SDValue LL, LH, RL, RH;
 454   DebugLoc dl = N->getDebugLoc();
 455   GetSplitOp(N->getOperand(1), LL, LH);
 456   GetSplitOp(N->getOperand(2), RL, RH);
 457
 458   SDValue Cond = N->getOperand(0);
 459   Lo = DAG.getNode(ISD::SELECT, dl, LL.getValueType(), Cond, LL, RL);
 460   Hi = DAG.getNode(ISD::SELECT, dl, LH.getValueType(), Cond, LH, RH);
 461 }
 462
 463 void DAGTypeLegalizer::SplitRes_SELECT_CC(SDNode *N, SDValue &Lo,
 464                                           SDValue &Hi) {
 465   SDValue LL, LH, RL, RH;
 466   DebugLoc dl = N->getDebugLoc();
 467   GetSplitOp(N->getOperand(2), LL, LH);
 468   GetSplitOp(N->getOperand(3), RL, RH);
 469
 470   Lo = DAG.getNode(ISD::SELECT_CC, dl, LL.getValueType(), N->getOperand(0),
 471                    N->getOperand(1), LL, RL, N->getOperand(4));
 472   Hi = DAG.getNode(ISD::SELECT_CC, dl, LH.getValueType(), N->getOperand(0),
 473                    N->getOperand(1), LH, RH, N->getOperand(4));
 474 }
 475
 476 void DAGTypeLegalizer::SplitRes_UNDEF(SDNode *N, SDValue &Lo, SDValue &Hi) {
 477   EVT LoVT, HiVT;
 478   GetSplitDestVTs(N->getValueType(0), LoVT, HiVT);
 479   Lo = DAG.getUNDEF(LoVT);
 480   Hi = DAG.getUNDEF(HiVT);
 481 }