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