llvm/lib/IR/Constants.cpp

   1 //===-- Constants.cpp - Implement Constant nodes --------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the Constant* classes.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/IR/Constants.h"
  14 #include "ConstantFold.h"
  15 #include "LLVMContextImpl.h"
  16 #include "llvm/ADT/STLExtras.h"
  17 #include "llvm/ADT/SmallVector.h"
  18 #include "llvm/ADT/StringMap.h"
  19 #include "llvm/IR/DerivedTypes.h"
  20 #include "llvm/IR/GetElementPtrTypeIterator.h"
  21 #include "llvm/IR/GlobalValue.h"
  22 #include "llvm/IR/Instructions.h"
  23 #include "llvm/IR/Module.h"
  24 #include "llvm/IR/Operator.h"
  25 #include "llvm/IR/PatternMatch.h"
  26 #include "llvm/Support/Debug.h"
  27 #include "llvm/Support/ErrorHandling.h"
  28 #include "llvm/Support/ManagedStatic.h"
  29 #include "llvm/Support/MathExtras.h"
  30 #include "llvm/Support/raw_ostream.h"
  31 #include <algorithm>
  32
  33 using namespace llvm;
  34 using namespace PatternMatch;
  35
  36 //===----------------------------------------------------------------------===//
  37 //                              Constant Class
  38 //===----------------------------------------------------------------------===//
  39
  40 bool Constant::isNegativeZeroValue() const {
  41   // Floating point values have an explicit -0.0 value.
  42   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
  43     return CFP->isZero() && CFP->isNegative();
  44
  45   // Equivalent for a vector of -0.0's.
  46   if (getType()->isVectorTy())
  47     if (const auto *SplatCFP = dyn_cast_or_null<ConstantFP>(getSplatValue()))
  48       return SplatCFP->isNegativeZeroValue();
  49
  50   // We've already handled true FP case; any other FP vectors can't represent -0.0.
  51   if (getType()->isFPOrFPVectorTy())
  52     return false;
  53
  54   // Otherwise, just use +0.0.
  55   return isNullValue();
  56 }
  57
  58 // Return true iff this constant is positive zero (floating point), negative
  59 // zero (floating point), or a null value.
  60 bool Constant::isZeroValue() const {
  61   // Floating point values have an explicit -0.0 value.
  62   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
  63     return CFP->isZero();
  64
  65   // Check for constant splat vectors of 1 values.
  66   if (getType()->isVectorTy())
  67     if (const auto *SplatCFP = dyn_cast_or_null<ConstantFP>(getSplatValue()))
  68       return SplatCFP->isZero();
  69
  70   // Otherwise, just use +0.0.
  71   return isNullValue();
  72 }
  73
  74 bool Constant::isNullValue() const {
  75   // 0 is null.
  76   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
  77     return CI->isZero();
  78
  79   // +0.0 is null.
  80   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
  81     // ppc_fp128 determine isZero using high order double only
  82     // Should check the bitwise value to make sure all bits are zero.
  83     return CFP->isExactlyValue(+0.0);
  84
  85   // constant zero is zero for aggregates, cpnull is null for pointers, none for
  86   // tokens.
  87   return isa<ConstantAggregateZero>(this) || isa<ConstantPointerNull>(this) ||
  88          isa<ConstantTokenNone>(this);
  89 }
  90
  91 bool Constant::isAllOnesValue() const {
  92   // Check for -1 integers
  93   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
  94     return CI->isMinusOne();
  95
  96   // Check for FP which are bitcasted from -1 integers
  97   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
  98     return CFP->getValueAPF().bitcastToAPInt().isAllOnesValue();
  99
 100   // Check for constant splat vectors of 1 values.
 101   if (getType()->isVectorTy())
 102     if (const auto *SplatVal = getSplatValue())
 103       return SplatVal->isAllOnesValue();
 104
 105   return false;
 106 }
 107
 108 bool Constant::isOneValue() const {
 109   // Check for 1 integers
 110   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
 111     return CI->isOne();
 112
 113   // Check for FP which are bitcasted from 1 integers
 114   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
 115     return CFP->getValueAPF().bitcastToAPInt().isOneValue();
 116
 117   // Check for constant splat vectors of 1 values.
 118   if (getType()->isVectorTy())
 119     if (const auto *SplatVal = getSplatValue())
 120       return SplatVal->isOneValue();
 121
 122   return false;
 123 }
 124
 125 bool Constant::isNotOneValue() const {
 126   // Check for 1 integers
 127   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
 128     return !CI->isOneValue();
 129
 130   // Check for FP which are bitcasted from 1 integers
 131   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
 132     return !CFP->getValueAPF().bitcastToAPInt().isOneValue();
 133
 134   // Check that vectors don't contain 1
 135   if (auto *VTy = dyn_cast<FixedVectorType>(getType())) {
 136     for (unsigned I = 0, E = VTy->getNumElements(); I != E; ++I) {
 137       Constant *Elt = getAggregateElement(I);
 138       if (!Elt || !Elt->isNotOneValue())
 139         return false;
 140     }
 141     return true;
 142   }
 143
 144   // Check for splats that don't contain 1
 145   if (getType()->isVectorTy())
 146     if (const auto *SplatVal = getSplatValue())
 147       return SplatVal->isNotOneValue();
 148
 149   // It *may* contain 1, we can't tell.
 150   return false;
 151 }
 152
 153 bool Constant::isMinSignedValue() const {
 154   // Check for INT_MIN integers
 155   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
 156     return CI->isMinValue(/*isSigned=*/true);
 157
 158   // Check for FP which are bitcasted from INT_MIN integers
 159   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
 160     return CFP->getValueAPF().bitcastToAPInt().isMinSignedValue();
 161
 162   // Check for splats of INT_MIN values.
 163   if (getType()->isVectorTy())
 164     if (const auto *SplatVal = getSplatValue())
 165       return SplatVal->isMinSignedValue();
 166
 167   return false;
 168 }
 169
 170 bool Constant::isNotMinSignedValue() const {
 171   // Check for INT_MIN integers
 172   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
 173     return !CI->isMinValue(/*isSigned=*/true);
 174
 175   // Check for FP which are bitcasted from INT_MIN integers
 176   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
 177     return !CFP->getValueAPF().bitcastToAPInt().isMinSignedValue();
 178
 179   // Check that vectors don't contain INT_MIN
 180   if (auto *VTy = dyn_cast<FixedVectorType>(getType())) {
 181     for (unsigned I = 0, E = VTy->getNumElements(); I != E; ++I) {
 182       Constant *Elt = getAggregateElement(I);
 183       if (!Elt || !Elt->isNotMinSignedValue())
 184         return false;
 185     }
 186     return true;
 187   }
 188
 189   // Check for splats that aren't INT_MIN
 190   if (getType()->isVectorTy())
 191     if (const auto *SplatVal = getSplatValue())
 192       return SplatVal->isNotMinSignedValue();
 193
 194   // It *may* contain INT_MIN, we can't tell.
 195   return false;
 196 }
 197
 198 bool Constant::isFiniteNonZeroFP() const {
 199   if (auto *CFP = dyn_cast<ConstantFP>(this))
 200     return CFP->getValueAPF().isFiniteNonZero();
 201
 202   if (auto *VTy = dyn_cast<FixedVectorType>(getType())) {
 203     for (unsigned I = 0, E = VTy->getNumElements(); I != E; ++I) {
 204       auto *CFP = dyn_cast_or_null<ConstantFP>(getAggregateElement(I));
 205       if (!CFP || !CFP->getValueAPF().isFiniteNonZero())
 206         return false;
 207     }
 208     return true;
 209   }
 210
 211   if (getType()->isVectorTy())
 212     if (const auto *SplatCFP = dyn_cast_or_null<ConstantFP>(getSplatValue()))
 213       return SplatCFP->isFiniteNonZeroFP();
 214
 215   // It *may* contain finite non-zero, we can't tell.
 216   return false;
 217 }
 218
 219 bool Constant::isNormalFP() const {
 220   if (auto *CFP = dyn_cast<ConstantFP>(this))
 221     return CFP->getValueAPF().isNormal();
 222
 223   if (auto *VTy = dyn_cast<FixedVectorType>(getType())) {
 224     for (unsigned I = 0, E = VTy->getNumElements(); I != E; ++I) {
 225       auto *CFP = dyn_cast_or_null<ConstantFP>(getAggregateElement(I));
 226       if (!CFP || !CFP->getValueAPF().isNormal())
 227         return false;
 228     }
 229     return true;
 230   }
 231
 232   if (getType()->isVectorTy())
 233     if (const auto *SplatCFP = dyn_cast_or_null<ConstantFP>(getSplatValue()))
 234       return SplatCFP->isNormalFP();
 235
 236   // It *may* contain a normal fp value, we can't tell.
 237   return false;
 238 }
 239
 240 bool Constant::hasExactInverseFP() const {
 241   if (auto *CFP = dyn_cast<ConstantFP>(this))
 242     return CFP->getValueAPF().getExactInverse(nullptr);
 243
 244   if (auto *VTy = dyn_cast<FixedVectorType>(getType())) {
 245     for (unsigned I = 0, E = VTy->getNumElements(); I != E; ++I) {
 246       auto *CFP = dyn_cast_or_null<ConstantFP>(getAggregateElement(I));
 247       if (!CFP || !CFP->getValueAPF().getExactInverse(nullptr))
 248         return false;
 249     }
 250     return true;
 251   }
 252
 253   if (getType()->isVectorTy())
 254     if (const auto *SplatCFP = dyn_cast_or_null<ConstantFP>(getSplatValue()))
 255       return SplatCFP->hasExactInverseFP();
 256
 257   // It *may* have an exact inverse fp value, we can't tell.
 258   return false;
 259 }
 260
 261 bool Constant::isNaN() const {
 262   if (auto *CFP = dyn_cast<ConstantFP>(this))
 263     return CFP->isNaN();
 264
 265   if (auto *VTy = dyn_cast<FixedVectorType>(getType())) {
 266     for (unsigned I = 0, E = VTy->getNumElements(); I != E; ++I) {
 267       auto *CFP = dyn_cast_or_null<ConstantFP>(getAggregateElement(I));
 268       if (!CFP || !CFP->isNaN())
 269         return false;
 270     }
 271     return true;
 272   }
 273
 274   if (getType()->isVectorTy())
 275     if (const auto *SplatCFP = dyn_cast_or_null<ConstantFP>(getSplatValue()))
 276       return SplatCFP->isNaN();
 277
 278   // It *may* be NaN, we can't tell.
 279   return false;
 280 }
 281
 282 bool Constant::isElementWiseEqual(Value *Y) const {
 283   // Are they fully identical?
 284   if (this == Y)
 285     return true;
 286
 287   // The input value must be a vector constant with the same type.
 288   auto *VTy = dyn_cast<VectorType>(getType());
 289   if (!isa<Constant>(Y) || !VTy || VTy != Y->getType())
 290     return false;
 291
 292   // TODO: Compare pointer constants?
 293   if (!(VTy->getElementType()->isIntegerTy() ||
 294         VTy->getElementType()->isFloatingPointTy()))
 295     return false;
 296
 297   // They may still be identical element-wise (if they have `undef`s).
 298   // Bitcast to integer to allow exact bitwise comparison for all types.
 299   Type *IntTy = VectorType::getInteger(VTy);
 300   Constant *C0 = ConstantExpr::getBitCast(const_cast<Constant *>(this), IntTy);
 301   Constant *C1 = ConstantExpr::getBitCast(cast<Constant>(Y), IntTy);
 302   Constant *CmpEq = ConstantExpr::getICmp(ICmpInst::ICMP_EQ, C0, C1);
 303   return isa<UndefValue>(CmpEq) || match(CmpEq, m_One());
 304 }
 305
 306 static bool
 307 containsUndefinedElement(const Constant *C,
 308                          function_ref<bool(const Constant *)> HasFn) {
 309   if (auto *VTy = dyn_cast<VectorType>(C->getType())) {
 310     if (HasFn(C))
 311       return true;
 312     if (isa<ConstantAggregateZero>(C))
 313       return false;
 314     if (isa<ScalableVectorType>(C->getType()))
 315       return false;
 316
 317     for (unsigned i = 0, e = cast<FixedVectorType>(VTy)->getNumElements();
 318          i != e; ++i)
 319       if (HasFn(C->getAggregateElement(i)))
 320         return true;
 321   }
 322
 323   return false;
 324 }
 325
 326 bool Constant::containsUndefOrPoisonElement() const {
 327   return containsUndefinedElement(
 328       this, [&](const auto *C) { return isa<UndefValue>(C); });
 329 }
 330
 331 bool Constant::containsPoisonElement() const {
 332   return containsUndefinedElement(
 333       this, [&](const auto *C) { return isa<PoisonValue>(C); });
 334 }
 335
 336 bool Constant::containsConstantExpression() const {
 337   if (auto *VTy = dyn_cast<FixedVectorType>(getType())) {
 338     for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i)
 339       if (isa<ConstantExpr>(getAggregateElement(i)))
 340         return true;
 341   }
 342   return false;
 343 }
 344
 345 /// Constructor to create a '0' constant of arbitrary type.
 346 Constant *Constant::getNullValue(Type *Ty) {
 347   switch (Ty->getTypeID()) {
 348   case Type::IntegerTyID:
 349     return ConstantInt::get(Ty, 0);
 350   case Type::HalfTyID:
 351     return ConstantFP::get(Ty->getContext(),
 352                            APFloat::getZero(APFloat::IEEEhalf()));
 353   case Type::BFloatTyID:
 354     return ConstantFP::get(Ty->getContext(),
 355                            APFloat::getZero(APFloat::BFloat()));
 356   case Type::FloatTyID:
 357     return ConstantFP::get(Ty->getContext(),
 358                            APFloat::getZero(APFloat::IEEEsingle()));
 359   case Type::DoubleTyID:
 360     return ConstantFP::get(Ty->getContext(),
 361                            APFloat::getZero(APFloat::IEEEdouble()));
 362   case Type::X86_FP80TyID:
 363     return ConstantFP::get(Ty->getContext(),
 364                            APFloat::getZero(APFloat::x87DoubleExtended()));
 365   case Type::FP128TyID:
 366     return ConstantFP::get(Ty->getContext(),
 367                            APFloat::getZero(APFloat::IEEEquad()));
 368   case Type::PPC_FP128TyID:
 369     return ConstantFP::get(Ty->getContext(),
 370                            APFloat(APFloat::PPCDoubleDouble(),
 371                                    APInt::getNullValue(128)));
 372   case Type::PointerTyID:
 373     return ConstantPointerNull::get(cast<PointerType>(Ty));
 374   case Type::StructTyID:
 375   case Type::ArrayTyID:
 376   case Type::FixedVectorTyID:
 377   case Type::ScalableVectorTyID:
 378     return ConstantAggregateZero::get(Ty);
 379   case Type::TokenTyID:
 380     return ConstantTokenNone::get(Ty->getContext());
 381   default:
 382     // Function, Label, or Opaque type?
 383     llvm_unreachable("Cannot create a null constant of that type!");
 384   }
 385 }
 386
 387 Constant *Constant::getIntegerValue(Type *Ty, const APInt &V) {
 388   Type *ScalarTy = Ty->getScalarType();
 389
 390   // Create the base integer constant.
 391   Constant *C = ConstantInt::get(Ty->getContext(), V);
 392
 393   // Convert an integer to a pointer, if necessary.
 394   if (PointerType *PTy = dyn_cast<PointerType>(ScalarTy))
 395     C = ConstantExpr::getIntToPtr(C, PTy);
 396
 397   // Broadcast a scalar to a vector, if necessary.
 398   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 399     C = ConstantVector::getSplat(VTy->getElementCount(), C);
 400
 401   return C;
 402 }
 403
 404 Constant *Constant::getAllOnesValue(Type *Ty) {
 405   if (IntegerType *ITy = dyn_cast<IntegerType>(Ty))
 406     return ConstantInt::get(Ty->getContext(),
 407                             APInt::getAllOnesValue(ITy->getBitWidth()));
 408
 409   if (Ty->isFloatingPointTy()) {
 410     APFloat FL = APFloat::getAllOnesValue(Ty->getFltSemantics(),
 411                                           Ty->getPrimitiveSizeInBits());
 412     return ConstantFP::get(Ty->getContext(), FL);
 413   }
 414
 415   VectorType *VTy = cast<VectorType>(Ty);
 416   return ConstantVector::getSplat(VTy->getElementCount(),
 417                                   getAllOnesValue(VTy->getElementType()));
 418 }
 419
 420 Constant *Constant::getAggregateElement(unsigned Elt) const {
 421   assert((getType()->isAggregateType() || getType()->isVectorTy()) &&
 422          "Must be an aggregate/vector constant");
 423
 424   if (const auto *CC = dyn_cast<ConstantAggregate>(this))
 425     return Elt < CC->getNumOperands() ? CC->getOperand(Elt) : nullptr;
 426
 427   if (const auto *CAZ = dyn_cast<ConstantAggregateZero>(this))
 428     return Elt < CAZ->getElementCount().getKnownMinValue()
 429                ? CAZ->getElementValue(Elt)
 430                : nullptr;
 431
 432   // FIXME: getNumElements() will fail for non-fixed vector types.
 433   if (isa<ScalableVectorType>(getType()))
 434     return nullptr;
 435
 436   if (const auto *PV = dyn_cast<PoisonValue>(this))
 437     return Elt < PV->getNumElements() ? PV->getElementValue(Elt) : nullptr;
 438
 439   if (const auto *UV = dyn_cast<UndefValue>(this))
 440     return Elt < UV->getNumElements() ? UV->getElementValue(Elt) : nullptr;
 441
 442   if (const auto *CDS = dyn_cast<ConstantDataSequential>(this))
 443     return Elt < CDS->getNumElements() ? CDS->getElementAsConstant(Elt)
 444                                        : nullptr;
 445
 446   return nullptr;
 447 }
 448
 449 Constant *Constant::getAggregateElement(Constant *Elt) const {
 450   assert(isa<IntegerType>(Elt->getType()) && "Index must be an integer");
 451   if (ConstantInt *CI = dyn_cast<ConstantInt>(Elt)) {
 452     // Check if the constant fits into an uint64_t.
 453     if (CI->getValue().getActiveBits() > 64)
 454       return nullptr;
 455     return getAggregateElement(CI->getZExtValue());
 456   }
 457   return nullptr;
 458 }
 459
 460 void Constant::destroyConstant() {
 461   /// First call destroyConstantImpl on the subclass.  This gives the subclass
 462   /// a chance to remove the constant from any maps/pools it's contained in.
 463   switch (getValueID()) {
 464   default:
 465     llvm_unreachable("Not a constant!");
 466 #define HANDLE_CONSTANT(Name)                                                  \
 467   case Value::Name##Val:                                                       \
 468     cast<Name>(this)->destroyConstantImpl();                                   \
 469     break;
 470 #include "llvm/IR/Value.def"
 471   }
 472
 473   // When a Constant is destroyed, there may be lingering
 474   // references to the constant by other constants in the constant pool.  These
 475   // constants are implicitly dependent on the module that is being deleted,
 476   // but they don't know that.  Because we only find out when the CPV is
 477   // deleted, we must now notify all of our users (that should only be
 478   // Constants) that they are, in fact, invalid now and should be deleted.
 479   //
 480   while (!use_empty()) {
 481     Value *V = user_back();
 482 #ifndef NDEBUG // Only in -g mode...
 483     if (!isa<Constant>(V)) {
 484       dbgs() << "While deleting: " << *this
 485              << "\n\nUse still stuck around after Def is destroyed: " << *V
 486              << "\n\n";
 487     }
 488 #endif
 489     assert(isa<Constant>(V) && "References remain to Constant being destroyed");
 490     cast<Constant>(V)->destroyConstant();
 491
 492     // The constant should remove itself from our use list...
 493     assert((use_empty() || user_back() != V) && "Constant not removed!");
 494   }
 495
 496   // Value has no outstanding references it is safe to delete it now...
 497   deleteConstant(this);
 498 }
 499
 500 void llvm::deleteConstant(Constant *C) {
 501   switch (C->getValueID()) {
 502   case Constant::ConstantIntVal:
 503     delete static_cast<ConstantInt *>(C);
 504     break;
 505   case Constant::ConstantFPVal:
 506     delete static_cast<ConstantFP *>(C);
 507     break;
 508   case Constant::ConstantAggregateZeroVal:
 509     delete static_cast<ConstantAggregateZero *>(C);
 510     break;
 511   case Constant::ConstantArrayVal:
 512     delete static_cast<ConstantArray *>(C);
 513     break;
 514   case Constant::ConstantStructVal:
 515     delete static_cast<ConstantStruct *>(C);
 516     break;
 517   case Constant::ConstantVectorVal:
 518     delete static_cast<ConstantVector *>(C);
 519     break;
 520   case Constant::ConstantPointerNullVal:
 521     delete static_cast<ConstantPointerNull *>(C);
 522     break;
 523   case Constant::ConstantDataArrayVal:
 524     delete static_cast<ConstantDataArray *>(C);
 525     break;
 526   case Constant::ConstantDataVectorVal:
 527     delete static_cast<ConstantDataVector *>(C);
 528     break;
 529   case Constant::ConstantTokenNoneVal:
 530     delete static_cast<ConstantTokenNone *>(C);
 531     break;
 532   case Constant::BlockAddressVal:
 533     delete static_cast<BlockAddress *>(C);
 534     break;
 535   case Constant::DSOLocalEquivalentVal:
 536     delete static_cast<DSOLocalEquivalent *>(C);
 537     break;
 538   case Constant::UndefValueVal:
 539     delete static_cast<UndefValue *>(C);
 540     break;
 541   case Constant::PoisonValueVal:
 542     delete static_cast<PoisonValue *>(C);
 543     break;
 544   case Constant::ConstantExprVal:
 545     if (isa<UnaryConstantExpr>(C))
 546       delete static_cast<UnaryConstantExpr *>(C);
 547     else if (isa<BinaryConstantExpr>(C))
 548       delete static_cast<BinaryConstantExpr *>(C);
 549     else if (isa<SelectConstantExpr>(C))
 550       delete static_cast<SelectConstantExpr *>(C);
 551     else if (isa<ExtractElementConstantExpr>(C))
 552       delete static_cast<ExtractElementConstantExpr *>(C);
 553     else if (isa<InsertElementConstantExpr>(C))
 554       delete static_cast<InsertElementConstantExpr *>(C);
 555     else if (isa<ShuffleVectorConstantExpr>(C))
 556       delete static_cast<ShuffleVectorConstantExpr *>(C);
 557     else if (isa<ExtractValueConstantExpr>(C))
 558       delete static_cast<ExtractValueConstantExpr *>(C);
 559     else if (isa<InsertValueConstantExpr>(C))
 560       delete static_cast<InsertValueConstantExpr *>(C);
 561     else if (isa<GetElementPtrConstantExpr>(C))
 562       delete static_cast<GetElementPtrConstantExpr *>(C);
 563     else if (isa<CompareConstantExpr>(C))
 564       delete static_cast<CompareConstantExpr *>(C);
 565     else
 566       llvm_unreachable("Unexpected constant expr");
 567     break;
 568   default:
 569     llvm_unreachable("Unexpected constant");
 570   }
 571 }
 572
 573 static bool canTrapImpl(const Constant *C,
 574                         SmallPtrSetImpl<const ConstantExpr *> &NonTrappingOps) {
 575   assert(C->getType()->isFirstClassType() && "Cannot evaluate aggregate vals!");
 576   // The only thing that could possibly trap are constant exprs.
 577   const ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
 578   if (!CE)
 579     return false;
 580
 581   // ConstantExpr traps if any operands can trap.
 582   for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
 583     if (ConstantExpr *Op = dyn_cast<ConstantExpr>(CE->getOperand(i))) {
 584       if (NonTrappingOps.insert(Op).second && canTrapImpl(Op, NonTrappingOps))
 585         return true;
 586     }
 587   }
 588
 589   // Otherwise, only specific operations can trap.
 590   switch (CE->getOpcode()) {
 591   default:
 592     return false;
 593   case Instruction::UDiv:
 594   case Instruction::SDiv:
 595   case Instruction::URem:
 596   case Instruction::SRem:
 597     // Div and rem can trap if the RHS is not known to be non-zero.
 598     if (!isa<ConstantInt>(CE->getOperand(1)) ||CE->getOperand(1)->isNullValue())
 599       return true;
 600     return false;
 601   }
 602 }
 603
 604 bool Constant::canTrap() const {
 605   SmallPtrSet<const ConstantExpr *, 4> NonTrappingOps;
 606   return canTrapImpl(this, NonTrappingOps);
 607 }
 608
 609 /// Check if C contains a GlobalValue for which Predicate is true.
 610 static bool
 611 ConstHasGlobalValuePredicate(const Constant *C,
 612                              bool (*Predicate)(const GlobalValue *)) {
 613   SmallPtrSet<const Constant *, 8> Visited;
 614   SmallVector<const Constant *, 8> WorkList;
 615   WorkList.push_back(C);
 616   Visited.insert(C);
 617
 618   while (!WorkList.empty()) {
 619     const Constant *WorkItem = WorkList.pop_back_val();
 620     if (const auto *GV = dyn_cast<GlobalValue>(WorkItem))
 621       if (Predicate(GV))
 622         return true;
 623     for (const Value *Op : WorkItem->operands()) {
 624       const Constant *ConstOp = dyn_cast<Constant>(Op);
 625       if (!ConstOp)
 626         continue;
 627       if (Visited.insert(ConstOp).second)
 628         WorkList.push_back(ConstOp);
 629     }
 630   }
 631   return false;
 632 }
 633
 634 bool Constant::isThreadDependent() const {
 635   auto DLLImportPredicate = [](const GlobalValue *GV) {
 636     return GV->isThreadLocal();
 637   };
 638   return ConstHasGlobalValuePredicate(this, DLLImportPredicate);
 639 }
 640
 641 bool Constant::isDLLImportDependent() const {
 642   auto DLLImportPredicate = [](const GlobalValue *GV) {
 643     return GV->hasDLLImportStorageClass();
 644   };
 645   return ConstHasGlobalValuePredicate(this, DLLImportPredicate);
 646 }
 647
 648 bool Constant::isConstantUsed() const {
 649   for (const User *U : users()) {
 650     const Constant *UC = dyn_cast<Constant>(U);
 651     if (!UC || isa<GlobalValue>(UC))
 652       return true;
 653
 654     if (UC->isConstantUsed())
 655       return true;
 656   }
 657   return false;
 658 }
 659
 660 bool Constant::needsDynamicRelocation() const {
 661   return getRelocationInfo() == GlobalRelocation;
 662 }
 663
 664 bool Constant::needsRelocation() const {
 665   return getRelocationInfo() != NoRelocation;
 666 }
 667
 668 Constant::PossibleRelocationsTy Constant::getRelocationInfo() const {
 669   if (isa<GlobalValue>(this))
 670     return GlobalRelocation; // Global reference.
 671
 672   if (const BlockAddress *BA = dyn_cast<BlockAddress>(this))
 673     return BA->getFunction()->getRelocationInfo();
 674
 675   if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) {
 676     if (CE->getOpcode() == Instruction::Sub) {
 677       ConstantExpr *LHS = dyn_cast<ConstantExpr>(CE->getOperand(0));
 678       ConstantExpr *RHS = dyn_cast<ConstantExpr>(CE->getOperand(1));
 679       if (LHS && RHS && LHS->getOpcode() == Instruction::PtrToInt &&
 680           RHS->getOpcode() == Instruction::PtrToInt) {
 681         Constant *LHSOp0 = LHS->getOperand(0);
 682         Constant *RHSOp0 = RHS->getOperand(0);
 683
 684         // While raw uses of blockaddress need to be relocated, differences
 685         // between two of them don't when they are for labels in the same
 686         // function.  This is a common idiom when creating a table for the
 687         // indirect goto extension, so we handle it efficiently here.
 688         if (isa<BlockAddress>(LHSOp0) && isa<BlockAddress>(RHSOp0) &&
 689             cast<BlockAddress>(LHSOp0)->getFunction() ==
 690                 cast<BlockAddress>(RHSOp0)->getFunction())
 691           return NoRelocation;
 692
 693         // Relative pointers do not need to be dynamically relocated.
 694         if (auto *RHSGV =
 695                 dyn_cast<GlobalValue>(RHSOp0->stripInBoundsConstantOffsets())) {
 696           auto *LHS = LHSOp0->stripInBoundsConstantOffsets();
 697           if (auto *LHSGV = dyn_cast<GlobalValue>(LHS)) {
 698             if (LHSGV->isDSOLocal() && RHSGV->isDSOLocal())
 699               return LocalRelocation;
 700           } else if (isa<DSOLocalEquivalent>(LHS)) {
 701             if (RHSGV->isDSOLocal())
 702               return LocalRelocation;
 703           }
 704         }
 705       }
 706     }
 707   }
 708
 709   PossibleRelocationsTy Result = NoRelocation;
 710   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
 711     Result =
 712         std::max(cast<Constant>(getOperand(i))->getRelocationInfo(), Result);
 713
 714   return Result;
 715 }
 716
 717 /// If the specified constantexpr is dead, remove it. This involves recursively
 718 /// eliminating any dead users of the constantexpr.
 719 static bool removeDeadUsersOfConstant(const Constant *C) {
 720   if (isa<GlobalValue>(C)) return false; // Cannot remove this
 721
 722   while (!C->use_empty()) {
 723     const Constant *User = dyn_cast<Constant>(C->user_back());
 724     if (!User) return false; // Non-constant usage;
 725     if (!removeDeadUsersOfConstant(User))
 726       return false; // Constant wasn't dead
 727   }
 728
 729   // If C is only used by metadata, it should not be preserved but should have
 730   // its uses replaced.
 731   if (C->isUsedByMetadata()) {
 732     const_cast<Constant *>(C)->replaceAllUsesWith(
 733         UndefValue::get(C->getType()));
 734   }
 735   const_cast<Constant*>(C)->destroyConstant();
 736   return true;
 737 }
 738
 739
 740 void Constant::removeDeadConstantUsers() const {
 741   Value::const_user_iterator I = user_begin(), E = user_end();
 742   Value::const_user_iterator LastNonDeadUser = E;
 743   while (I != E) {
 744     const Constant *User = dyn_cast<Constant>(*I);
 745     if (!User) {
 746       LastNonDeadUser = I;
 747       ++I;
 748       continue;
 749     }
 750
 751     if (!removeDeadUsersOfConstant(User)) {
 752       // If the constant wasn't dead, remember that this was the last live use
 753       // and move on to the next constant.
 754       LastNonDeadUser = I;
 755       ++I;
 756       continue;
 757     }
 758
 759     // If the constant was dead, then the iterator is invalidated.
 760     if (LastNonDeadUser == E)
 761       I = user_begin();
 762     else
 763       I = std::next(LastNonDeadUser);
 764   }
 765 }
 766
 767 Constant *Constant::replaceUndefsWith(Constant *C, Constant *Replacement) {
 768   assert(C && Replacement && "Expected non-nullptr constant arguments");
 769   Type *Ty = C->getType();
 770   if (match(C, m_Undef())) {
 771     assert(Ty == Replacement->getType() && "Expected matching types");
 772     return Replacement;
 773   }
 774
 775   // Don't know how to deal with this constant.
 776   auto *VTy = dyn_cast<FixedVectorType>(Ty);
 777   if (!VTy)
 778     return C;
 779
 780   unsigned NumElts = VTy->getNumElements();
 781   SmallVector<Constant *, 32> NewC(NumElts);
 782   for (unsigned i = 0; i != NumElts; ++i) {
 783     Constant *EltC = C->getAggregateElement(i);
 784     assert((!EltC || EltC->getType() == Replacement->getType()) &&
 785            "Expected matching types");
 786     NewC[i] = EltC && match(EltC, m_Undef()) ? Replacement : EltC;
 787   }
 788   return ConstantVector::get(NewC);
 789 }
 790
 791 Constant *Constant::mergeUndefsWith(Constant *C, Constant *Other) {
 792   assert(C && Other && "Expected non-nullptr constant arguments");
 793   if (match(C, m_Undef()))
 794     return C;
 795
 796   Type *Ty = C->getType();
 797   if (match(Other, m_Undef()))
 798     return UndefValue::get(Ty);
 799
 800   auto *VTy = dyn_cast<FixedVectorType>(Ty);
 801   if (!VTy)
 802     return C;
 803
 804   Type *EltTy = VTy->getElementType();
 805   unsigned NumElts = VTy->getNumElements();
 806   assert(isa<FixedVectorType>(Other->getType()) &&
 807          cast<FixedVectorType>(Other->getType())->getNumElements() == NumElts &&
 808          "Type mismatch");
 809
 810   bool FoundExtraUndef = false;
 811   SmallVector<Constant *, 32> NewC(NumElts);
 812   for (unsigned I = 0; I != NumElts; ++I) {
 813     NewC[I] = C->getAggregateElement(I);
 814     Constant *OtherEltC = Other->getAggregateElement(I);
 815     assert(NewC[I] && OtherEltC && "Unknown vector element");
 816     if (!match(NewC[I], m_Undef()) && match(OtherEltC, m_Undef())) {
 817       NewC[I] = UndefValue::get(EltTy);
 818       FoundExtraUndef = true;
 819     }
 820   }
 821   if (FoundExtraUndef)
 822     return ConstantVector::get(NewC);
 823   return C;
 824 }
 825
 826 bool Constant::isManifestConstant() const {
 827   if (isa<ConstantData>(this))
 828     return true;
 829   if (isa<ConstantAggregate>(this) || isa<ConstantExpr>(this)) {
 830     for (const Value *Op : operand_values())
 831       if (!cast<Constant>(Op)->isManifestConstant())
 832         return false;
 833     return true;
 834   }
 835   return false;
 836 }
 837
 838 //===----------------------------------------------------------------------===//
 839 //                                ConstantInt
 840 //===----------------------------------------------------------------------===//
 841
 842 ConstantInt::ConstantInt(IntegerType *Ty, const APInt &V)
 843     : ConstantData(Ty, ConstantIntVal), Val(V) {
 844   assert(V.getBitWidth() == Ty->getBitWidth() && "Invalid constant for type");
 845 }
 846
 847 ConstantInt *ConstantInt::getTrue(LLVMContext &Context) {
 848   LLVMContextImpl *pImpl = Context.pImpl;
 849   if (!pImpl->TheTrueVal)
 850     pImpl->TheTrueVal = ConstantInt::get(Type::getInt1Ty(Context), 1);
 851   return pImpl->TheTrueVal;
 852 }
 853
 854 ConstantInt *ConstantInt::getFalse(LLVMContext &Context) {
 855   LLVMContextImpl *pImpl = Context.pImpl;
 856   if (!pImpl->TheFalseVal)
 857     pImpl->TheFalseVal = ConstantInt::get(Type::getInt1Ty(Context), 0);
 858   return pImpl->TheFalseVal;
 859 }
 860
 861 ConstantInt *ConstantInt::getBool(LLVMContext &Context, bool V) {
 862   return V ? getTrue(Context) : getFalse(Context);
 863 }
 864
 865 Constant *ConstantInt::getTrue(Type *Ty) {
 866   assert(Ty->isIntOrIntVectorTy(1) && "Type not i1 or vector of i1.");
 867   ConstantInt *TrueC = ConstantInt::getTrue(Ty->getContext());
 868   if (auto *VTy = dyn_cast<VectorType>(Ty))
 869     return ConstantVector::getSplat(VTy->getElementCount(), TrueC);
 870   return TrueC;
 871 }
 872
 873 Constant *ConstantInt::getFalse(Type *Ty) {
 874   assert(Ty->isIntOrIntVectorTy(1) && "Type not i1 or vector of i1.");
 875   ConstantInt *FalseC = ConstantInt::getFalse(Ty->getContext());
 876   if (auto *VTy = dyn_cast<VectorType>(Ty))
 877     return ConstantVector::getSplat(VTy->getElementCount(), FalseC);
 878   return FalseC;
 879 }
 880
 881 Constant *ConstantInt::getBool(Type *Ty, bool V) {
 882   return V ? getTrue(Ty) : getFalse(Ty);
 883 }
 884
 885 // Get a ConstantInt from an APInt.
 886 ConstantInt *ConstantInt::get(LLVMContext &Context, const APInt &V) {
 887   // get an existing value or the insertion position
 888   LLVMContextImpl *pImpl = Context.pImpl;
 889   std::unique_ptr<ConstantInt> &Slot = pImpl->IntConstants[V];
 890   if (!Slot) {
 891     // Get the corresponding integer type for the bit width of the value.
 892     IntegerType *ITy = IntegerType::get(Context, V.getBitWidth());
 893     Slot.reset(new ConstantInt(ITy, V));
 894   }
 895   assert(Slot->getType() == IntegerType::get(Context, V.getBitWidth()));
 896   return Slot.get();
 897 }
 898
 899 Constant *ConstantInt::get(Type *Ty, uint64_t V, bool isSigned) {
 900   Constant *C = get(cast<IntegerType>(Ty->getScalarType()), V, isSigned);
 901
 902   // For vectors, broadcast the value.
 903   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 904     return ConstantVector::getSplat(VTy->getElementCount(), C);
 905
 906   return C;
 907 }
 908
 909 ConstantInt *ConstantInt::get(IntegerType *Ty, uint64_t V, bool isSigned) {
 910   return get(Ty->getContext(), APInt(Ty->getBitWidth(), V, isSigned));
 911 }
 912
 913 ConstantInt *ConstantInt::getSigned(IntegerType *Ty, int64_t V) {
 914   return get(Ty, V, true);
 915 }
 916
 917 Constant *ConstantInt::getSigned(Type *Ty, int64_t V) {
 918   return get(Ty, V, true);
 919 }
 920
 921 Constant *ConstantInt::get(Type *Ty, const APInt& V) {
 922   ConstantInt *C = get(Ty->getContext(), V);
 923   assert(C->getType() == Ty->getScalarType() &&
 924          "ConstantInt type doesn't match the type implied by its value!");
 925
 926   // For vectors, broadcast the value.
 927   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 928     return ConstantVector::getSplat(VTy->getElementCount(), C);
 929
 930   return C;
 931 }
 932
 933 ConstantInt *ConstantInt::get(IntegerType* Ty, StringRef Str, uint8_t radix) {
 934   return get(Ty->getContext(), APInt(Ty->getBitWidth(), Str, radix));
 935 }
 936
 937 /// Remove the constant from the constant table.
 938 void ConstantInt::destroyConstantImpl() {
 939   llvm_unreachable("You can't ConstantInt->destroyConstantImpl()!");
 940 }
 941
 942 //===----------------------------------------------------------------------===//
 943 //                                ConstantFP
 944 //===----------------------------------------------------------------------===//
 945
 946 Constant *ConstantFP::get(Type *Ty, double V) {
 947   LLVMContext &Context = Ty->getContext();
 948
 949   APFloat FV(V);
 950   bool ignored;
 951   FV.convert(Ty->getScalarType()->getFltSemantics(),
 952              APFloat::rmNearestTiesToEven, &ignored);
 953   Constant *C = get(Context, FV);
 954
 955   // For vectors, broadcast the value.
 956   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 957     return ConstantVector::getSplat(VTy->getElementCount(), C);
 958
 959   return C;
 960 }
 961
 962 Constant *ConstantFP::get(Type *Ty, const APFloat &V) {
 963   ConstantFP *C = get(Ty->getContext(), V);
 964   assert(C->getType() == Ty->getScalarType() &&
 965          "ConstantFP type doesn't match the type implied by its value!");
 966
 967   // For vectors, broadcast the value.
 968   if (auto *VTy = dyn_cast<VectorType>(Ty))
 969     return ConstantVector::getSplat(VTy->getElementCount(), C);
 970
 971   return C;
 972 }
 973
 974 Constant *ConstantFP::get(Type *Ty, StringRef Str) {
 975   LLVMContext &Context = Ty->getContext();
 976
 977   APFloat FV(Ty->getScalarType()->getFltSemantics(), Str);
 978   Constant *C = get(Context, FV);
 979
 980   // For vectors, broadcast the value.
 981   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 982     return ConstantVector::getSplat(VTy->getElementCount(), C);
 983
 984   return C;
 985 }
 986
 987 Constant *ConstantFP::getNaN(Type *Ty, bool Negative, uint64_t Payload) {
 988   const fltSemantics &Semantics = Ty->getScalarType()->getFltSemantics();
 989   APFloat NaN = APFloat::getNaN(Semantics, Negative, Payload);
 990   Constant *C = get(Ty->getContext(), NaN);
 991
 992   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 993     return ConstantVector::getSplat(VTy->getElementCount(), C);
 994
 995   return C;
 996 }
 997
 998 Constant *ConstantFP::getQNaN(Type *Ty, bool Negative, APInt *Payload) {
 999   const fltSemantics &Semantics = Ty->getScalarType()->getFltSemantics();
1000   APFloat NaN = APFloat::getQNaN(Semantics, Negative, Payload);
1001   Constant *C = get(Ty->getContext(), NaN);
1002
1003   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
1004     return ConstantVector::getSplat(VTy->getElementCount(), C);
1005
1006   return C;
1007 }
1008
1009 Constant *ConstantFP::getSNaN(Type *Ty, bool Negative, APInt *Payload) {
1010   const fltSemantics &Semantics = Ty->getScalarType()->getFltSemantics();
1011   APFloat NaN = APFloat::getSNaN(Semantics, Negative, Payload);
1012   Constant *C = get(Ty->getContext(), NaN);
1013
1014   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
1015     return ConstantVector::getSplat(VTy->getElementCount(), C);
1016
1017   return C;
1018 }
1019
1020 Constant *ConstantFP::getNegativeZero(Type *Ty) {
1021   const fltSemantics &Semantics = Ty->getScalarType()->getFltSemantics();
1022   APFloat NegZero = APFloat::getZero(Semantics, /*Negative=*/true);
1023   Constant *C = get(Ty->getContext(), NegZero);
1024
1025   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
1026     return ConstantVector::getSplat(VTy->getElementCount(), C);
1027
1028   return C;
1029 }
1030
1031
1032 Constant *ConstantFP::getZeroValueForNegation(Type *Ty) {
1033   if (Ty->isFPOrFPVectorTy())
1034     return getNegativeZero(Ty);
1035
1036   return Constant::getNullValue(Ty);
1037 }
1038
1039
1040 // ConstantFP accessors.
1041 ConstantFP* ConstantFP::get(LLVMContext &Context, const APFloat& V) {
1042   LLVMContextImpl* pImpl = Context.pImpl;
1043
1044   std::unique_ptr<ConstantFP> &Slot = pImpl->FPConstants[V];
1045
1046   if (!Slot) {
1047     Type *Ty = Type::getFloatingPointTy(Context, V.getSemantics());
1048     Slot.reset(new ConstantFP(Ty, V));
1049   }
1050
1051   return Slot.get();
1052 }
1053
1054 Constant *ConstantFP::getInfinity(Type *Ty, bool Negative) {
1055   const fltSemantics &Semantics = Ty->getScalarType()->getFltSemantics();
1056   Constant *C = get(Ty->getContext(), APFloat::getInf(Semantics, Negative));
1057
1058   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
1059     return ConstantVector::getSplat(VTy->getElementCount(), C);
1060
1061   return C;
1062 }
1063
1064 ConstantFP::ConstantFP(Type *Ty, const APFloat &V)
1065     : ConstantData(Ty, ConstantFPVal), Val(V) {
1066   assert(&V.getSemantics() == &Ty->getFltSemantics() &&
1067          "FP type Mismatch");
1068 }
1069
1070 bool ConstantFP::isExactlyValue(const APFloat &V) const {
1071   return Val.bitwiseIsEqual(V);
1072 }
1073
1074 /// Remove the constant from the constant table.
1075 void ConstantFP::destroyConstantImpl() {
1076   llvm_unreachable("You can't ConstantFP->destroyConstantImpl()!");
1077 }
1078
1079 //===----------------------------------------------------------------------===//
1080 //                   ConstantAggregateZero Implementation
1081 //===----------------------------------------------------------------------===//
1082
1083 Constant *ConstantAggregateZero::getSequentialElement() const {
1084   if (auto *AT = dyn_cast<ArrayType>(getType()))
1085     return Constant::getNullValue(AT->getElementType());
1086   return Constant::getNullValue(cast<VectorType>(getType())->getElementType());
1087 }
1088
1089 Constant *ConstantAggregateZero::getStructElement(unsigned Elt) const {
1090   return Constant::getNullValue(getType()->getStructElementType(Elt));
1091 }
1092
1093 Constant *ConstantAggregateZero::getElementValue(Constant *C) const {
1094   if (isa<ArrayType>(getType()) || isa<VectorType>(getType()))
1095     return getSequentialElement();
1096   return getStructElement(cast<ConstantInt>(C)->getZExtValue());
1097 }
1098
1099 Constant *ConstantAggregateZero::getElementValue(unsigned Idx) const {
1100   if (isa<ArrayType>(getType()) || isa<VectorType>(getType()))
1101     return getSequentialElement();
1102   return getStructElement(Idx);
1103 }
1104
1105 ElementCount ConstantAggregateZero::getElementCount() const {
1106   Type *Ty = getType();
1107   if (auto *AT = dyn_cast<ArrayType>(Ty))
1108     return ElementCount::getFixed(AT->getNumElements());
1109   if (auto *VT = dyn_cast<VectorType>(Ty))
1110     return VT->getElementCount();
1111   return ElementCount::getFixed(Ty->getStructNumElements());
1112 }
1113
1114 //===----------------------------------------------------------------------===//
1115 //                         UndefValue Implementation
1116 //===----------------------------------------------------------------------===//
1117
1118 UndefValue *UndefValue::getSequentialElement() const {
1119   if (ArrayType *ATy = dyn_cast<ArrayType>(getType()))
1120     return UndefValue::get(ATy->getElementType());
1121   return UndefValue::get(cast<VectorType>(getType())->getElementType());
1122 }
1123
1124 UndefValue *UndefValue::getStructElement(unsigned Elt) const {
1125   return UndefValue::get(getType()->getStructElementType(Elt));
1126 }
1127
1128 UndefValue *UndefValue::getElementValue(Constant *C) const {
1129   if (isa<ArrayType>(getType()) || isa<VectorType>(getType()))
1130     return getSequentialElement();
1131   return getStructElement(cast<ConstantInt>(C)->getZExtValue());
1132 }
1133
1134 UndefValue *UndefValue::getElementValue(unsigned Idx) const {
1135   if (isa<ArrayType>(getType()) || isa<VectorType>(getType()))
1136     return getSequentialElement();
1137   return getStructElement(Idx);
1138 }
1139
1140 unsigned UndefValue::getNumElements() const {
1141   Type *Ty = getType();
1142   if (auto *AT = dyn_cast<ArrayType>(Ty))
1143     return AT->getNumElements();
1144   if (auto *VT = dyn_cast<VectorType>(Ty))
1145     return cast<FixedVectorType>(VT)->getNumElements();
1146   return Ty->getStructNumElements();
1147 }
1148
1149 //===----------------------------------------------------------------------===//
1150 //                         PoisonValue Implementation
1151 //===----------------------------------------------------------------------===//
1152
1153 PoisonValue *PoisonValue::getSequentialElement() const {
1154   if (ArrayType *ATy = dyn_cast<ArrayType>(getType()))
1155     return PoisonValue::get(ATy->getElementType());
1156   return PoisonValue::get(cast<VectorType>(getType())->getElementType());
1157 }
1158
1159 PoisonValue *PoisonValue::getStructElement(unsigned Elt) const {
1160   return PoisonValue::get(getType()->getStructElementType(Elt));
1161 }
1162
1163 PoisonValue *PoisonValue::getElementValue(Constant *C) const {
1164   if (isa<ArrayType>(getType()) || isa<VectorType>(getType()))
1165     return getSequentialElement();
1166   return getStructElement(cast<ConstantInt>(C)->getZExtValue());
1167 }
1168
1169 PoisonValue *PoisonValue::getElementValue(unsigned Idx) const {
1170   if (isa<ArrayType>(getType()) || isa<VectorType>(getType()))
1171     return getSequentialElement();
1172   return getStructElement(Idx);
1173 }
1174
1175 //===----------------------------------------------------------------------===//
1176 //                            ConstantXXX Classes
1177 //===----------------------------------------------------------------------===//
1178
1179 template <typename ItTy, typename EltTy>
1180 static bool rangeOnlyContains(ItTy Start, ItTy End, EltTy Elt) {
1181   for (; Start != End; ++Start)
1182     if (*Start != Elt)
1183       return false;
1184   return true;
1185 }
1186
1187 template <typename SequentialTy, typename ElementTy>
1188 static Constant *getIntSequenceIfElementsMatch(ArrayRef<Constant *> V) {
1189   assert(!V.empty() && "Cannot get empty int sequence.");
1190
1191   SmallVector<ElementTy, 16> Elts;
1192   for (Constant *C : V)
1193     if (auto *CI = dyn_cast<ConstantInt>(C))
1194       Elts.push_back(CI->getZExtValue());
1195     else
1196       return nullptr;
1197   return SequentialTy::get(V[0]->getContext(), Elts);
1198 }
1199
1200 template <typename SequentialTy, typename ElementTy>
1201 static Constant *getFPSequenceIfElementsMatch(ArrayRef<Constant *> V) {
1202   assert(!V.empty() && "Cannot get empty FP sequence.");
1203
1204   SmallVector<ElementTy, 16> Elts;
1205   for (Constant *C : V)
1206     if (auto *CFP = dyn_cast<ConstantFP>(C))
1207       Elts.push_back(CFP->getValueAPF().bitcastToAPInt().getLimitedValue());
1208     else
1209       return nullptr;
1210   return SequentialTy::getFP(V[0]->getType(), Elts);
1211 }
1212
1213 template <typename SequenceTy>
1214 static Constant *getSequenceIfElementsMatch(Constant *C,
1215                                             ArrayRef<Constant *> V) {
1216   // We speculatively build the elements here even if it turns out that there is
1217   // a constantexpr or something else weird, since it is so uncommon for that to
1218   // happen.
1219   if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
1220     if (CI->getType()->isIntegerTy(8))
1221       return getIntSequenceIfElementsMatch<SequenceTy, uint8_t>(V);
1222     else if (CI->getType()->isIntegerTy(16))
1223       return getIntSequenceIfElementsMatch<SequenceTy, uint16_t>(V);
1224     else if (CI->getType()->isIntegerTy(32))
1225       return getIntSequenceIfElementsMatch<SequenceTy, uint32_t>(V);
1226     else if (CI->getType()->isIntegerTy(64))
1227       return getIntSequenceIfElementsMatch<SequenceTy, uint64_t>(V);
1228   } else if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
1229     if (CFP->getType()->isHalfTy() || CFP->getType()->isBFloatTy())
1230       return getFPSequenceIfElementsMatch<SequenceTy, uint16_t>(V);
1231     else if (CFP->getType()->isFloatTy())
1232       return getFPSequenceIfElementsMatch<SequenceTy, uint32_t>(V);
1233     else if (CFP->getType()->isDoubleTy())
1234       return getFPSequenceIfElementsMatch<SequenceTy, uint64_t>(V);
1235   }
1236
1237   return nullptr;
1238 }
1239
1240 ConstantAggregate::ConstantAggregate(Type *T, ValueTy VT,
1241                                      ArrayRef<Constant *> V)
1242     : Constant(T, VT, OperandTraits<ConstantAggregate>::op_end(this) - V.size(),
1243                V.size()) {
1244   llvm::copy(V, op_begin());
1245
1246   // Check that types match, unless this is an opaque struct.
1247   if (auto *ST = dyn_cast<StructType>(T)) {
1248     if (ST->isOpaque())
1249       return;
1250     for (unsigned I = 0, E = V.size(); I != E; ++I)
1251       assert(V[I]->getType() == ST->getTypeAtIndex(I) &&
1252              "Initializer for struct element doesn't match!");
1253   }
1254 }
1255
1256 ConstantArray::ConstantArray(ArrayType *T, ArrayRef<Constant *> V)
1257     : ConstantAggregate(T, ConstantArrayVal, V) {
1258   assert(V.size() == T->getNumElements() &&
1259          "Invalid initializer for constant array");
1260 }
1261
1262 Constant *ConstantArray::get(ArrayType *Ty, ArrayRef<Constant*> V) {
1263   if (Constant *C = getImpl(Ty, V))
1264     return C;
1265   return Ty->getContext().pImpl->ArrayConstants.getOrCreate(Ty, V);
1266 }
1267
1268 Constant *ConstantArray::getImpl(ArrayType *Ty, ArrayRef<Constant*> V) {
1269   // Empty arrays are canonicalized to ConstantAggregateZero.
1270   if (V.empty())
1271     return ConstantAggregateZero::get(Ty);
1272
1273   for (unsigned i = 0, e = V.size(); i != e; ++i) {
1274     assert(V[i]->getType() == Ty->getElementType() &&
1275            "Wrong type in array element initializer");
1276   }
1277
1278   // If this is an all-zero array, return a ConstantAggregateZero object.  If
1279   // all undef, return an UndefValue, if "all simple", then return a
1280   // ConstantDataArray.
1281   Constant *C = V[0];
1282   if (isa<PoisonValue>(C) && rangeOnlyContains(V.begin(), V.end(), C))
1283     return PoisonValue::get(Ty);
1284
1285   if (isa<UndefValue>(C) && rangeOnlyContains(V.begin(), V.end(), C))
1286     return UndefValue::get(Ty);
1287
1288   if (C->isNullValue() && rangeOnlyContains(V.begin(), V.end(), C))
1289     return ConstantAggregateZero::get(Ty);
1290
1291   // Check to see if all of the elements are ConstantFP or ConstantInt and if
1292   // the element type is compatible with ConstantDataVector.  If so, use it.
1293   if (ConstantDataSequential::isElementTypeCompatible(C->getType()))
1294     return getSequenceIfElementsMatch<ConstantDataArray>(C, V);
1295
1296   // Otherwise, we really do want to create a ConstantArray.
1297   return nullptr;
1298 }
1299
1300 StructType *ConstantStruct::getTypeForElements(LLVMContext &Context,
1301                                                ArrayRef<Constant*> V,
1302                                                bool Packed) {
1303   unsigned VecSize = V.size();
1304   SmallVector<Type*, 16> EltTypes(VecSize);
1305   for (unsigned i = 0; i != VecSize; ++i)
1306     EltTypes[i] = V[i]->getType();
1307
1308   return StructType::get(Context, EltTypes, Packed);
1309 }
1310
1311
1312 StructType *ConstantStruct::getTypeForElements(ArrayRef<Constant*> V,
1313                                                bool Packed) {
1314   assert(!V.empty() &&
1315          "ConstantStruct::getTypeForElements cannot be called on empty list");
1316   return getTypeForElements(V[0]->getContext(), V, Packed);
1317 }
1318
1319 ConstantStruct::ConstantStruct(StructType *T, ArrayRef<Constant *> V)
1320     : ConstantAggregate(T, ConstantStructVal, V) {
1321   assert((T->isOpaque() || V.size() == T->getNumElements()) &&
1322          "Invalid initializer for constant struct");
1323 }
1324
1325 // ConstantStruct accessors.
1326 Constant *ConstantStruct::get(StructType *ST, ArrayRef<Constant*> V) {
1327   assert((ST->isOpaque() || ST->getNumElements() == V.size()) &&
1328          "Incorrect # elements specified to ConstantStruct::get");
1329
1330   // Create a ConstantAggregateZero value if all elements are zeros.
1331   bool isZero = true;
1332   bool isUndef = false;
1333   bool isPoison = false;
1334
1335   if (!V.empty()) {
1336     isUndef = isa<UndefValue>(V[0]);
1337     isPoison = isa<PoisonValue>(V[0]);
1338     isZero = V[0]->isNullValue();
1339     // PoisonValue inherits UndefValue, so its check is not necessary.
1340     if (isUndef || isZero) {
1341       for (unsigned i = 0, e = V.size(); i != e; ++i) {
1342         if (!V[i]->isNullValue())
1343           isZero = false;
1344         if (!isa<PoisonValue>(V[i]))
1345           isPoison = false;
1346         if (isa<PoisonValue>(V[i]) || !isa<UndefValue>(V[i]))
1347           isUndef = false;
1348       }
1349     }
1350   }
1351   if (isZero)
1352     return ConstantAggregateZero::get(ST);
1353   if (isPoison)
1354     return PoisonValue::get(ST);
1355   if (isUndef)
1356     return UndefValue::get(ST);
1357
1358   return ST->getContext().pImpl->StructConstants.getOrCreate(ST, V);
1359 }
1360
1361 ConstantVector::ConstantVector(VectorType *T, ArrayRef<Constant *> V)
1362     : ConstantAggregate(T, ConstantVectorVal, V) {
1363   assert(V.size() == cast<FixedVectorType>(T)->getNumElements() &&
1364          "Invalid initializer for constant vector");
1365 }
1366
1367 // ConstantVector accessors.
1368 Constant *ConstantVector::get(ArrayRef<Constant*> V) {
1369   if (Constant *C = getImpl(V))
1370     return C;
1371   auto *Ty = FixedVectorType::get(V.front()->getType(), V.size());
1372   return Ty->getContext().pImpl->VectorConstants.getOrCreate(Ty, V);
1373 }
1374
1375 Constant *ConstantVector::getImpl(ArrayRef<Constant*> V) {
1376   assert(!V.empty() && "Vectors can't be empty");
1377   auto *T = FixedVectorType::get(V.front()->getType(), V.size());
1378
1379   // If this is an all-undef or all-zero vector, return a
1380   // ConstantAggregateZero or UndefValue.
1381   Constant *C = V[0];
1382   bool isZero = C->isNullValue();
1383   bool isUndef = isa<UndefValue>(C);
1384   bool isPoison = isa<PoisonValue>(C);
1385
1386   if (isZero || isUndef) {
1387     for (unsigned i = 1, e = V.size(); i != e; ++i)
1388       if (V[i] != C) {
1389         isZero = isUndef = isPoison = false;
1390         break;
1391       }
1392   }
1393
1394   if (isZero)
1395     return ConstantAggregateZero::get(T);
1396   if (isPoison)
1397     return PoisonValue::get(T);
1398   if (isUndef)
1399     return UndefValue::get(T);
1400
1401   // Check to see if all of the elements are ConstantFP or ConstantInt and if
1402   // the element type is compatible with ConstantDataVector.  If so, use it.
1403   if (ConstantDataSequential::isElementTypeCompatible(C->getType()))
1404     return getSequenceIfElementsMatch<ConstantDataVector>(C, V);
1405
1406   // Otherwise, the element type isn't compatible with ConstantDataVector, or
1407   // the operand list contains a ConstantExpr or something else strange.
1408   return nullptr;
1409 }
1410
1411 Constant *ConstantVector::getSplat(ElementCount EC, Constant *V) {
1412   if (!EC.isScalable()) {
1413     // If this splat is compatible with ConstantDataVector, use it instead of
1414     // ConstantVector.
1415     if ((isa<ConstantFP>(V) || isa<ConstantInt>(V)) &&
1416         ConstantDataSequential::isElementTypeCompatible(V->getType()))
1417       return ConstantDataVector::getSplat(EC.getKnownMinValue(), V);
1418
1419     SmallVector<Constant *, 32> Elts(EC.getKnownMinValue(), V);
1420     return get(Elts);
1421   }
1422
1423   Type *VTy = VectorType::get(V->getType(), EC);
1424
1425   if (V->isNullValue())
1426     return ConstantAggregateZero::get(VTy);
1427   else if (isa<UndefValue>(V))
1428     return UndefValue::get(VTy);
1429
1430   Type *I32Ty = Type::getInt32Ty(VTy->getContext());
1431
1432   // Move scalar into vector.
1433   Constant *PoisonV = PoisonValue::get(VTy);
1434   V = ConstantExpr::getInsertElement(PoisonV, V, ConstantInt::get(I32Ty, 0));
1435   // Build shuffle mask to perform the splat.
1436   SmallVector<int, 8> Zeros(EC.getKnownMinValue(), 0);
1437   // Splat.
1438   return ConstantExpr::getShuffleVector(V, PoisonV, Zeros);
1439 }
1440
1441 ConstantTokenNone *ConstantTokenNone::get(LLVMContext &Context) {
1442   LLVMContextImpl *pImpl = Context.pImpl;
1443   if (!pImpl->TheNoneToken)
1444     pImpl->TheNoneToken.reset(new ConstantTokenNone(Context));
1445   return pImpl->TheNoneToken.get();
1446 }
1447
1448 /// Remove the constant from the constant table.
1449 void ConstantTokenNone::destroyConstantImpl() {
1450   llvm_unreachable("You can't ConstantTokenNone->destroyConstantImpl()!");
1451 }
1452
1453 // Utility function for determining if a ConstantExpr is a CastOp or not. This
1454 // can't be inline because we don't want to #include Instruction.h into
1455 // Constant.h
1456 bool ConstantExpr::isCast() const {
1457   return Instruction::isCast(getOpcode());
1458 }
1459
1460 bool ConstantExpr::isCompare() const {
1461   return getOpcode() == Instruction::ICmp || getOpcode() == Instruction::FCmp;
1462 }
1463
1464 bool ConstantExpr::isGEPWithNoNotionalOverIndexing() const {
1465   if (getOpcode() != Instruction::GetElementPtr) return false;
1466
1467   gep_type_iterator GEPI = gep_type_begin(this), E = gep_type_end(this);
1468   User::const_op_iterator OI = std::next(this->op_begin());
1469
1470   // The remaining indices may be compile-time known integers within the bounds
1471   // of the corresponding notional static array types.
1472   for (; GEPI != E; ++GEPI, ++OI) {
1473     if (isa<UndefValue>(*OI))
1474       continue;
1475     auto *CI = dyn_cast<ConstantInt>(*OI);
1476     if (!CI || (GEPI.isBoundedSequential() &&
1477                 (CI->getValue().getActiveBits() > 64 ||
1478                  CI->getZExtValue() >= GEPI.getSequentialNumElements())))
1479       return false;
1480   }
1481
1482   // All the indices checked out.
1483   return true;
1484 }
1485
1486 bool ConstantExpr::hasIndices() const {
1487   return getOpcode() == Instruction::ExtractValue ||
1488          getOpcode() == Instruction::InsertValue;
1489 }
1490
1491 ArrayRef<unsigned> ConstantExpr::getIndices() const {
1492   if (const ExtractValueConstantExpr *EVCE =
1493         dyn_cast<ExtractValueConstantExpr>(this))
1494     return EVCE->Indices;
1495
1496   return cast<InsertValueConstantExpr>(this)->Indices;
1497 }
1498
1499 unsigned ConstantExpr::getPredicate() const {
1500   return cast<CompareConstantExpr>(this)->predicate;
1501 }
1502
1503 ArrayRef<int> ConstantExpr::getShuffleMask() const {
1504   return cast<ShuffleVectorConstantExpr>(this)->ShuffleMask;
1505 }
1506
1507 Constant *ConstantExpr::getShuffleMaskForBitcode() const {
1508   return cast<ShuffleVectorConstantExpr>(this)->ShuffleMaskForBitcode;
1509 }
1510
1511 Constant *
1512 ConstantExpr::getWithOperandReplaced(unsigned OpNo, Constant *Op) const {
1513   assert(Op->getType() == getOperand(OpNo)->getType() &&
1514          "Replacing operand with value of different type!");
1515   if (getOperand(OpNo) == Op)
1516     return const_cast<ConstantExpr*>(this);
1517
1518   SmallVector<Constant*, 8> NewOps;
1519   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
1520     NewOps.push_back(i == OpNo ? Op : getOperand(i));
1521
1522   return getWithOperands(NewOps);
1523 }
1524
1525 Constant *ConstantExpr::getWithOperands(ArrayRef<Constant *> Ops, Type *Ty,
1526                                         bool OnlyIfReduced, Type *SrcTy) const {
1527   assert(Ops.size() == getNumOperands() && "Operand count mismatch!");
1528
1529   // If no operands changed return self.
1530   if (Ty == getType() && std::equal(Ops.begin(), Ops.end(), op_begin()))
1531     return const_cast<ConstantExpr*>(this);
1532
1533   Type *OnlyIfReducedTy = OnlyIfReduced ? Ty : nullptr;
1534   switch (getOpcode()) {
1535   case Instruction::Trunc:
1536   case Instruction::ZExt:
1537   case Instruction::SExt:
1538   case Instruction::FPTrunc:
1539   case Instruction::FPExt:
1540   case Instruction::UIToFP:
1541   case Instruction::SIToFP:
1542   case Instruction::FPToUI:
1543   case Instruction::FPToSI:
1544   case Instruction::PtrToInt:
1545   case Instruction::IntToPtr:
1546   case Instruction::BitCast:
1547   case Instruction::AddrSpaceCast:
1548     return ConstantExpr::getCast(getOpcode(), Ops[0], Ty, OnlyIfReduced);
1549   case Instruction::Select:
1550     return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2], OnlyIfReducedTy);
1551   case Instruction::InsertElement:
1552     return ConstantExpr::getInsertElement(Ops[0], Ops[1], Ops[2],
1553                                           OnlyIfReducedTy);
1554   case Instruction::ExtractElement:
1555     return ConstantExpr::getExtractElement(Ops[0], Ops[1], OnlyIfReducedTy);
1556   case Instruction::InsertValue:
1557     return ConstantExpr::getInsertValue(Ops[0], Ops[1], getIndices(),
1558                                         OnlyIfReducedTy);
1559   case Instruction::ExtractValue:
1560     return ConstantExpr::getExtractValue(Ops[0], getIndices(), OnlyIfReducedTy);
1561   case Instruction::FNeg:
1562     return ConstantExpr::getFNeg(Ops[0]);
1563   case Instruction::ShuffleVector:
1564     return ConstantExpr::getShuffleVector(Ops[0], Ops[1], getShuffleMask(),
1565                                           OnlyIfReducedTy);
1566   case Instruction::GetElementPtr: {
1567     auto *GEPO = cast<GEPOperator>(this);
1568     assert(SrcTy || (Ops[0]->getType() == getOperand(0)->getType()));
1569     return ConstantExpr::getGetElementPtr(
1570         SrcTy ? SrcTy : GEPO->getSourceElementType(), Ops[0], Ops.slice(1),
1571         GEPO->isInBounds(), GEPO->getInRangeIndex(), OnlyIfReducedTy);
1572   }
1573   case Instruction::ICmp:
1574   case Instruction::FCmp:
1575     return ConstantExpr::getCompare(getPredicate(), Ops[0], Ops[1],
1576                                     OnlyIfReducedTy);
1577   default:
1578     assert(getNumOperands() == 2 && "Must be binary operator?");
1579     return ConstantExpr::get(getOpcode(), Ops[0], Ops[1], SubclassOptionalData,
1580                              OnlyIfReducedTy);
1581   }
1582 }
1583
1584
1585 //===----------------------------------------------------------------------===//
1586 //                      isValueValidForType implementations
1587
1588 bool ConstantInt::isValueValidForType(Type *Ty, uint64_t Val) {
1589   unsigned NumBits = Ty->getIntegerBitWidth(); // assert okay
1590   if (Ty->isIntegerTy(1))
1591     return Val == 0 || Val == 1;
1592   return isUIntN(NumBits, Val);
1593 }
1594
1595 bool ConstantInt::isValueValidForType(Type *Ty, int64_t Val) {
1596   unsigned NumBits = Ty->getIntegerBitWidth();
1597   if (Ty->isIntegerTy(1))
1598     return Val == 0 || Val == 1 || Val == -1;
1599   return isIntN(NumBits, Val);
1600 }
1601
1602 bool ConstantFP::isValueValidForType(Type *Ty, const APFloat& Val) {
1603   // convert modifies in place, so make a copy.
1604   APFloat Val2 = APFloat(Val);
1605   bool losesInfo;
1606   switch (Ty->getTypeID()) {
1607   default:
1608     return false;         // These can't be represented as floating point!
1609
1610   // FIXME rounding mode needs to be more flexible
1611   case Type::HalfTyID: {
1612     if (&Val2.getSemantics() == &APFloat::IEEEhalf())
1613       return true;
1614     Val2.convert(APFloat::IEEEhalf(), APFloat::rmNearestTiesToEven, &losesInfo);
1615     return !losesInfo;
1616   }
1617   case Type::BFloatTyID: {
1618     if (&Val2.getSemantics() == &APFloat::BFloat())
1619       return true;
1620     Val2.convert(APFloat::BFloat(), APFloat::rmNearestTiesToEven, &losesInfo);
1621     return !losesInfo;
1622   }
1623   case Type::FloatTyID: {
1624     if (&Val2.getSemantics() == &APFloat::IEEEsingle())
1625       return true;
1626     Val2.convert(APFloat::IEEEsingle(), APFloat::rmNearestTiesToEven, &losesInfo);
1627     return !losesInfo;
1628   }
1629   case Type::DoubleTyID: {
1630     if (&Val2.getSemantics() == &APFloat::IEEEhalf() ||
1631         &Val2.getSemantics() == &APFloat::BFloat() ||
1632         &Val2.getSemantics() == &APFloat::IEEEsingle() ||
1633         &Val2.getSemantics() == &APFloat::IEEEdouble())
1634       return true;
1635     Val2.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven, &losesInfo);
1636     return !losesInfo;
1637   }
1638   case Type::X86_FP80TyID:
1639     return &Val2.getSemantics() == &APFloat::IEEEhalf() ||
1640            &Val2.getSemantics() == &APFloat::BFloat() ||
1641            &Val2.getSemantics() == &APFloat::IEEEsingle() ||
1642            &Val2.getSemantics() == &APFloat::IEEEdouble() ||
1643            &Val2.getSemantics() == &APFloat::x87DoubleExtended();
1644   case Type::FP128TyID:
1645     return &Val2.getSemantics() == &APFloat::IEEEhalf() ||
1646            &Val2.getSemantics() == &APFloat::BFloat() ||
1647            &Val2.getSemantics() == &APFloat::IEEEsingle() ||
1648            &Val2.getSemantics() == &APFloat::IEEEdouble() ||
1649            &Val2.getSemantics() == &APFloat::IEEEquad();
1650   case Type::PPC_FP128TyID:
1651     return &Val2.getSemantics() == &APFloat::IEEEhalf() ||
1652            &Val2.getSemantics() == &APFloat::BFloat() ||
1653            &Val2.getSemantics() == &APFloat::IEEEsingle() ||
1654            &Val2.getSemantics() == &APFloat::IEEEdouble() ||
1655            &Val2.getSemantics() == &APFloat::PPCDoubleDouble();
1656   }
1657 }
1658
1659
1660 //===----------------------------------------------------------------------===//
1661 //                      Factory Function Implementation
1662
1663 ConstantAggregateZero *ConstantAggregateZero::get(Type *Ty) {
1664   assert((Ty->isStructTy() || Ty->isArrayTy() || Ty->isVectorTy()) &&
1665          "Cannot create an aggregate zero of non-aggregate type!");
1666
1667   std::unique_ptr<ConstantAggregateZero> &Entry =
1668       Ty->getContext().pImpl->CAZConstants[Ty];
1669   if (!Entry)
1670     Entry.reset(new ConstantAggregateZero(Ty));
1671
1672   return Entry.get();
1673 }
1674
1675 /// Remove the constant from the constant table.
1676 void ConstantAggregateZero::destroyConstantImpl() {
1677   getContext().pImpl->CAZConstants.erase(getType());
1678 }
1679
1680 /// Remove the constant from the constant table.
1681 void ConstantArray::destroyConstantImpl() {
1682   getType()->getContext().pImpl->ArrayConstants.remove(this);
1683 }
1684
1685
1686 //---- ConstantStruct::get() implementation...
1687 //
1688
1689 /// Remove the constant from the constant table.
1690 void ConstantStruct::destroyConstantImpl() {
1691   getType()->getContext().pImpl->StructConstants.remove(this);
1692 }
1693
1694 /// Remove the constant from the constant table.
1695 void ConstantVector::destroyConstantImpl() {
1696   getType()->getContext().pImpl->VectorConstants.remove(this);
1697 }
1698
1699 Constant *Constant::getSplatValue(bool AllowUndefs) const {
1700   assert(this->getType()->isVectorTy() && "Only valid for vectors!");
1701   if (isa<ConstantAggregateZero>(this))
1702     return getNullValue(cast<VectorType>(getType())->getElementType());
1703   if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
1704     return CV->getSplatValue();
1705   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
1706     return CV->getSplatValue(AllowUndefs);
1707
1708   // Check if this is a constant expression splat of the form returned by
1709   // ConstantVector::getSplat()
1710   const auto *Shuf = dyn_cast<ConstantExpr>(this);
1711   if (Shuf && Shuf->getOpcode() == Instruction::ShuffleVector &&
1712       isa<UndefValue>(Shuf->getOperand(1))) {
1713
1714     const auto *IElt = dyn_cast<ConstantExpr>(Shuf->getOperand(0));
1715     if (IElt && IElt->getOpcode() == Instruction::InsertElement &&
1716         isa<UndefValue>(IElt->getOperand(0))) {
1717
1718       ArrayRef<int> Mask = Shuf->getShuffleMask();
1719       Constant *SplatVal = IElt->getOperand(1);
1720       ConstantInt *Index = dyn_cast<ConstantInt>(IElt->getOperand(2));
1721
1722       if (Index && Index->getValue() == 0 &&
1723           llvm::all_of(Mask, [](int I) { return I == 0; }))
1724         return SplatVal;
1725     }
1726   }
1727
1728   return nullptr;
1729 }
1730
1731 Constant *ConstantVector::getSplatValue(bool AllowUndefs) const {
1732   // Check out first element.
1733   Constant *Elt = getOperand(0);
1734   // Then make sure all remaining elements point to the same value.
1735   for (unsigned I = 1, E = getNumOperands(); I < E; ++I) {
1736     Constant *OpC = getOperand(I);
1737     if (OpC == Elt)
1738       continue;
1739
1740     // Strict mode: any mismatch is not a splat.
1741     if (!AllowUndefs)
1742       return nullptr;
1743
1744     // Allow undefs mode: ignore undefined elements.
1745     if (isa<UndefValue>(OpC))
1746       continue;
1747
1748     // If we do not have a defined element yet, use the current operand.
1749     if (isa<UndefValue>(Elt))
1750       Elt = OpC;
1751
1752     if (OpC != Elt)
1753       return nullptr;
1754   }
1755   return Elt;
1756 }
1757
1758 const APInt &Constant::getUniqueInteger() const {
1759   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
1760     return CI->getValue();
1761   assert(this->getSplatValue() && "Doesn't contain a unique integer!");
1762   const Constant *C = this->getAggregateElement(0U);
1763   assert(C && isa<ConstantInt>(C) && "Not a vector of numbers!");
1764   return cast<ConstantInt>(C)->getValue();
1765 }
1766
1767 //---- ConstantPointerNull::get() implementation.
1768 //
1769
1770 ConstantPointerNull *ConstantPointerNull::get(PointerType *Ty) {
1771   std::unique_ptr<ConstantPointerNull> &Entry =
1772       Ty->getContext().pImpl->CPNConstants[Ty];
1773   if (!Entry)
1774     Entry.reset(new ConstantPointerNull(Ty));
1775
1776   return Entry.get();
1777 }
1778
1779 /// Remove the constant from the constant table.
1780 void ConstantPointerNull::destroyConstantImpl() {
1781   getContext().pImpl->CPNConstants.erase(getType());
1782 }
1783
1784 UndefValue *UndefValue::get(Type *Ty) {
1785   std::unique_ptr<UndefValue> &Entry = Ty->getContext().pImpl->UVConstants[Ty];
1786   if (!Entry)
1787     Entry.reset(new UndefValue(Ty));
1788
1789   return Entry.get();
1790 }
1791
1792 /// Remove the constant from the constant table.
1793 void UndefValue::destroyConstantImpl() {
1794   // Free the constant and any dangling references to it.
1795   if (getValueID() == UndefValueVal) {
1796     getContext().pImpl->UVConstants.erase(getType());
1797   } else if (getValueID() == PoisonValueVal) {
1798     getContext().pImpl->PVConstants.erase(getType());
1799   }
1800   llvm_unreachable("Not a undef or a poison!");
1801 }
1802
1803 PoisonValue *PoisonValue::get(Type *Ty) {
1804   std::unique_ptr<PoisonValue> &Entry = Ty->getContext().pImpl->PVConstants[Ty];
1805   if (!Entry)
1806     Entry.reset(new PoisonValue(Ty));
1807
1808   return Entry.get();
1809 }
1810
1811 /// Remove the constant from the constant table.
1812 void PoisonValue::destroyConstantImpl() {
1813   // Free the constant and any dangling references to it.
1814   getContext().pImpl->PVConstants.erase(getType());
1815 }
1816
1817 BlockAddress *BlockAddress::get(BasicBlock *BB) {
1818   assert(BB->getParent() && "Block must have a parent");
1819   return get(BB->getParent(), BB);
1820 }
1821
1822 BlockAddress *BlockAddress::get(Function *F, BasicBlock *BB) {
1823   BlockAddress *&BA =
1824     F->getContext().pImpl->BlockAddresses[std::make_pair(F, BB)];
1825   if (!BA)
1826     BA = new BlockAddress(F, BB);
1827
1828   assert(BA->getFunction() == F && "Basic block moved between functions");
1829   return BA;
1830 }
1831
1832 BlockAddress::BlockAddress(Function *F, BasicBlock *BB)
1833     : Constant(Type::getInt8PtrTy(F->getContext(), F->getAddressSpace()),
1834                Value::BlockAddressVal, &Op<0>(), 2) {
1835   setOperand(0, F);
1836   setOperand(1, BB);
1837   BB->AdjustBlockAddressRefCount(1);
1838 }
1839
1840 BlockAddress *BlockAddress::lookup(const BasicBlock *BB) {
1841   if (!BB->hasAddressTaken())
1842     return nullptr;
1843
1844   const Function *F = BB->getParent();
1845   assert(F && "Block must have a parent");
1846   BlockAddress *BA =
1847       F->getContext().pImpl->BlockAddresses.lookup(std::make_pair(F, BB));
1848   assert(BA && "Refcount and block address map disagree!");
1849   return BA;
1850 }
1851
1852 /// Remove the constant from the constant table.
1853 void BlockAddress::destroyConstantImpl() {
1854   getFunction()->getType()->getContext().pImpl
1855     ->BlockAddresses.erase(std::make_pair(getFunction(), getBasicBlock()));
1856   getBasicBlock()->AdjustBlockAddressRefCount(-1);
1857 }
1858
1859 Value *BlockAddress::handleOperandChangeImpl(Value *From, Value *To) {
1860   // This could be replacing either the Basic Block or the Function.  In either
1861   // case, we have to remove the map entry.
1862   Function *NewF = getFunction();
1863   BasicBlock *NewBB = getBasicBlock();
1864
1865   if (From == NewF)
1866     NewF = cast<Function>(To->stripPointerCasts());
1867   else {
1868     assert(From == NewBB && "From does not match any operand");
1869     NewBB = cast<BasicBlock>(To);
1870   }
1871
1872   // See if the 'new' entry already exists, if not, just update this in place
1873   // and return early.
1874   BlockAddress *&NewBA =
1875     getContext().pImpl->BlockAddresses[std::make_pair(NewF, NewBB)];
1876   if (NewBA)
1877     return NewBA;
1878
1879   getBasicBlock()->AdjustBlockAddressRefCount(-1);
1880
1881   // Remove the old entry, this can't cause the map to rehash (just a
1882   // tombstone will get added).
1883   getContext().pImpl->BlockAddresses.erase(std::make_pair(getFunction(),
1884                                                           getBasicBlock()));
1885   NewBA = this;
1886   setOperand(0, NewF);
1887   setOperand(1, NewBB);
1888   getBasicBlock()->AdjustBlockAddressRefCount(1);
1889
1890   // If we just want to keep the existing value, then return null.
1891   // Callers know that this means we shouldn't delete this value.
1892   return nullptr;
1893 }
1894
1895 DSOLocalEquivalent *DSOLocalEquivalent::get(GlobalValue *GV) {
1896   DSOLocalEquivalent *&Equiv = GV->getContext().pImpl->DSOLocalEquivalents[GV];
1897   if (!Equiv)
1898     Equiv = new DSOLocalEquivalent(GV);
1899
1900   assert(Equiv->getGlobalValue() == GV &&
1901          "DSOLocalFunction does not match the expected global value");
1902   return Equiv;
1903 }
1904
1905 DSOLocalEquivalent::DSOLocalEquivalent(GlobalValue *GV)
1906     : Constant(GV->getType(), Value::DSOLocalEquivalentVal, &Op<0>(), 1) {
1907   setOperand(0, GV);
1908 }
1909
1910 /// Remove the constant from the constant table.
1911 void DSOLocalEquivalent::destroyConstantImpl() {
1912   const GlobalValue *GV = getGlobalValue();
1913   GV->getContext().pImpl->DSOLocalEquivalents.erase(GV);
1914 }
1915
1916 Value *DSOLocalEquivalent::handleOperandChangeImpl(Value *From, Value *To) {
1917   assert(From == getGlobalValue() && "Changing value does not match operand.");
1918   assert(isa<Constant>(To) && "Can only replace the operands with a constant");
1919
1920   // The replacement is with another global value.
1921   if (const auto *ToObj = dyn_cast<GlobalValue>(To)) {
1922     DSOLocalEquivalent *&NewEquiv =
1923         getContext().pImpl->DSOLocalEquivalents[ToObj];
1924     if (NewEquiv)
1925       return llvm::ConstantExpr::getBitCast(NewEquiv, getType());
1926   }
1927
1928   // If the argument is replaced with a null value, just replace this constant
1929   // with a null value.
1930   if (cast<Constant>(To)->isNullValue())
1931     return To;
1932
1933   // The replacement could be a bitcast or an alias to another function. We can
1934   // replace it with a bitcast to the dso_local_equivalent of that function.
1935   auto *Func = cast<Function>(To->stripPointerCastsAndAliases());
1936   DSOLocalEquivalent *&NewEquiv = getContext().pImpl->DSOLocalEquivalents[Func];
1937   if (NewEquiv)
1938     return llvm::ConstantExpr::getBitCast(NewEquiv, getType());
1939
1940   // Replace this with the new one.
1941   getContext().pImpl->DSOLocalEquivalents.erase(getGlobalValue());
1942   NewEquiv = this;
1943   setOperand(0, Func);
1944
1945   if (Func->getType() != getType()) {
1946     // It is ok to mutate the type here because this constant should always
1947     // reflect the type of the function it's holding.
1948     mutateType(Func->getType());
1949   }
1950   return nullptr;
1951 }
1952
1953 //---- ConstantExpr::get() implementations.
1954 //
1955
1956 /// This is a utility function to handle folding of casts and lookup of the
1957 /// cast in the ExprConstants map. It is used by the various get* methods below.
1958 static Constant *getFoldedCast(Instruction::CastOps opc, Constant *C, Type *Ty,
1959                                bool OnlyIfReduced = false) {
1960   assert(Ty->isFirstClassType() && "Cannot cast to an aggregate type!");
1961   // Fold a few common cases
1962   if (Constant *FC = ConstantFoldCastInstruction(opc, C, Ty))
1963     return FC;
1964
1965   if (OnlyIfReduced)
1966     return nullptr;
1967
1968   LLVMContextImpl *pImpl = Ty->getContext().pImpl;
1969
1970   // Look up the constant in the table first to ensure uniqueness.
1971   ConstantExprKeyType Key(opc, C);
1972
1973   return pImpl->ExprConstants.getOrCreate(Ty, Key);
1974 }
1975
1976 Constant *ConstantExpr::getCast(unsigned oc, Constant *C, Type *Ty,
1977                                 bool OnlyIfReduced) {
1978   Instruction::CastOps opc = Instruction::CastOps(oc);
1979   assert(Instruction::isCast(opc) && "opcode out of range");
1980   assert(C && Ty && "Null arguments to getCast");
1981   assert(CastInst::castIsValid(opc, C, Ty) && "Invalid constantexpr cast!");
1982
1983   switch (opc) {
1984   default:
1985     llvm_unreachable("Invalid cast opcode");
1986   case Instruction::Trunc:
1987     return getTrunc(C, Ty, OnlyIfReduced);
1988   case Instruction::ZExt:
1989     return getZExt(C, Ty, OnlyIfReduced);
1990   case Instruction::SExt:
1991     return getSExt(C, Ty, OnlyIfReduced);
1992   case Instruction::FPTrunc:
1993     return getFPTrunc(C, Ty, OnlyIfReduced);
1994   case Instruction::FPExt:
1995     return getFPExtend(C, Ty, OnlyIfReduced);
1996   case Instruction::UIToFP:
1997     return getUIToFP(C, Ty, OnlyIfReduced);
1998   case Instruction::SIToFP:
1999     return getSIToFP(C, Ty, OnlyIfReduced);
2000   case Instruction::FPToUI:
2001     return getFPToUI(C, Ty, OnlyIfReduced);
2002   case Instruction::FPToSI:
2003     return getFPToSI(C, Ty, OnlyIfReduced);
2004   case Instruction::PtrToInt:
2005     return getPtrToInt(C, Ty, OnlyIfReduced);
2006   case Instruction::IntToPtr:
2007     return getIntToPtr(C, Ty, OnlyIfReduced);
2008   case Instruction::BitCast:
2009     return getBitCast(C, Ty, OnlyIfReduced);
2010   case Instruction::AddrSpaceCast:
2011     return getAddrSpaceCast(C, Ty, OnlyIfReduced);
2012   }
2013 }
2014
2015 Constant *ConstantExpr::getZExtOrBitCast(Constant *C, Type *Ty) {
2016   if (C->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
2017     return getBitCast(C, Ty);
2018   return getZExt(C, Ty);
2019 }
2020
2021 Constant *ConstantExpr::getSExtOrBitCast(Constant *C, Type *Ty) {
2022   if (C->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
2023     return getBitCast(C, Ty);
2024   return getSExt(C, Ty);
2025 }
2026
2027 Constant *ConstantExpr::getTruncOrBitCast(Constant *C, Type *Ty) {
2028   if (C->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
2029     return getBitCast(C, Ty);
2030   return getTrunc(C, Ty);
2031 }
2032
2033 Constant *ConstantExpr::getPointerCast(Constant *S, Type *Ty) {
2034   assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
2035   assert((Ty->isIntOrIntVectorTy() || Ty->isPtrOrPtrVectorTy()) &&
2036           "Invalid cast");
2037
2038   if (Ty->isIntOrIntVectorTy())
2039     return getPtrToInt(S, Ty);
2040
2041   unsigned SrcAS = S->getType()->getPointerAddressSpace();
2042   if (Ty->isPtrOrPtrVectorTy() && SrcAS != Ty->getPointerAddressSpace())
2043     return getAddrSpaceCast(S, Ty);
2044
2045   return getBitCast(S, Ty);
2046 }
2047
2048 Constant *ConstantExpr::getPointerBitCastOrAddrSpaceCast(Constant *S,
2049                                                          Type *Ty) {
2050   assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
2051   assert(Ty->isPtrOrPtrVectorTy() && "Invalid cast");
2052
2053   if (S->getType()->getPointerAddressSpace() != Ty->getPointerAddressSpace())
2054     return getAddrSpaceCast(S, Ty);
2055
2056   return getBitCast(S, Ty);
2057 }
2058
2059 Constant *ConstantExpr::getIntegerCast(Constant *C, Type *Ty, bool isSigned) {
2060   assert(C->getType()->isIntOrIntVectorTy() &&
2061          Ty->isIntOrIntVectorTy() && "Invalid cast");
2062   unsigned SrcBits = C->getType()->getScalarSizeInBits();
2063   unsigned DstBits = Ty->getScalarSizeInBits();
2064   Instruction::CastOps opcode =
2065     (SrcBits == DstBits ? Instruction::BitCast :
2066      (SrcBits > DstBits ? Instruction::Trunc :
2067       (isSigned ? Instruction::SExt : Instruction::ZExt)));
2068   return getCast(opcode, C, Ty);
2069 }
2070
2071 Constant *ConstantExpr::getFPCast(Constant *C, Type *Ty) {
2072   assert(C->getType()->isFPOrFPVectorTy() && Ty->isFPOrFPVectorTy() &&
2073          "Invalid cast");
2074   unsigned SrcBits = C->getType()->getScalarSizeInBits();
2075   unsigned DstBits = Ty->getScalarSizeInBits();
2076   if (SrcBits == DstBits)
2077     return C; // Avoid a useless cast
2078   Instruction::CastOps opcode =
2079     (SrcBits > DstBits ? Instruction::FPTrunc : Instruction::FPExt);
2080   return getCast(opcode, C, Ty);
2081 }
2082
2083 Constant *ConstantExpr::getTrunc(Constant *C, Type *Ty, bool OnlyIfReduced) {
2084 #ifndef NDEBUG
2085   bool fromVec = isa<VectorType>(C->getType());
2086   bool toVec = isa<VectorType>(Ty);
2087 #endif
2088   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
2089   assert(C->getType()->isIntOrIntVectorTy() && "Trunc operand must be integer");
2090   assert(Ty->isIntOrIntVectorTy() && "Trunc produces only integral");
2091   assert(C->getType()->getScalarSizeInBits() > Ty->getScalarSizeInBits()&&
2092          "SrcTy must be larger than DestTy for Trunc!");
2093
2094   return getFoldedCast(Instruction::Trunc, C, Ty, OnlyIfReduced);
2095 }
2096
2097 Constant *ConstantExpr::getSExt(Constant *C, Type *Ty, bool OnlyIfReduced) {
2098 #ifndef NDEBUG
2099   bool fromVec = isa<VectorType>(C->getType());
2100   bool toVec = isa<VectorType>(Ty);
2101 #endif
2102   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
2103   assert(C->getType()->isIntOrIntVectorTy() && "SExt operand must be integral");
2104   assert(Ty->isIntOrIntVectorTy() && "SExt produces only integer");
2105   assert(C->getType()->getScalarSizeInBits() < Ty->getScalarSizeInBits()&&
2106          "SrcTy must be smaller than DestTy for SExt!");
2107
2108   return getFoldedCast(Instruction::SExt, C, Ty, OnlyIfReduced);
2109 }
2110
2111 Constant *ConstantExpr::getZExt(Constant *C, Type *Ty, bool OnlyIfReduced) {
2112 #ifndef NDEBUG
2113   bool fromVec = isa<VectorType>(C->getType());
2114   bool toVec = isa<VectorType>(Ty);
2115 #endif
2116   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
2117   assert(C->getType()->isIntOrIntVectorTy() && "ZEXt operand must be integral");
2118   assert(Ty->isIntOrIntVectorTy() && "ZExt produces only integer");
2119   assert(C->getType()->getScalarSizeInBits() < Ty->getScalarSizeInBits()&&
2120          "SrcTy must be smaller than DestTy for ZExt!");
2121
2122   return getFoldedCast(Instruction::ZExt, C, Ty, OnlyIfReduced);
2123 }
2124
2125 Constant *ConstantExpr::getFPTrunc(Constant *C, Type *Ty, bool OnlyIfReduced) {
2126 #ifndef NDEBUG
2127   bool fromVec = isa<VectorType>(C->getType());
2128   bool toVec = isa<VectorType>(Ty);
2129 #endif
2130   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
2131   assert(C->getType()->isFPOrFPVectorTy() && Ty->isFPOrFPVectorTy() &&
2132          C->getType()->getScalarSizeInBits() > Ty->getScalarSizeInBits()&&
2133          "This is an illegal floating point truncation!");
2134   return getFoldedCast(Instruction::FPTrunc, C, Ty, OnlyIfReduced);
2135 }
2136
2137 Constant *ConstantExpr::getFPExtend(Constant *C, Type *Ty, bool OnlyIfReduced) {
2138 #ifndef NDEBUG
2139   bool fromVec = isa<VectorType>(C->getType());
2140   bool toVec = isa<VectorType>(Ty);
2141 #endif
2142   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
2143   assert(C->getType()->isFPOrFPVectorTy() && Ty->isFPOrFPVectorTy() &&
2144          C->getType()->getScalarSizeInBits() < Ty->getScalarSizeInBits()&&
2145          "This is an illegal floating point extension!");
2146   return getFoldedCast(Instruction::FPExt, C, Ty, OnlyIfReduced);
2147 }
2148
2149 Constant *ConstantExpr::getUIToFP(Constant *C, Type *Ty, bool OnlyIfReduced) {
2150 #ifndef NDEBUG
2151   bool fromVec = isa<VectorType>(C->getType());
2152   bool toVec = isa<VectorType>(Ty);
2153 #endif
2154   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
2155   assert(C->getType()->isIntOrIntVectorTy() && Ty->isFPOrFPVectorTy() &&
2156          "This is an illegal uint to floating point cast!");
2157   return getFoldedCast(Instruction::UIToFP, C, Ty, OnlyIfReduced);
2158 }
2159
2160 Constant *ConstantExpr::getSIToFP(Constant *C, Type *Ty, bool OnlyIfReduced) {
2161 #ifndef NDEBUG
2162   bool fromVec = isa<VectorType>(C->getType());
2163   bool toVec = isa<VectorType>(Ty);
2164 #endif
2165   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
2166   assert(C->getType()->isIntOrIntVectorTy() && Ty->isFPOrFPVectorTy() &&
2167          "This is an illegal sint to floating point cast!");
2168   return getFoldedCast(Instruction::SIToFP, C, Ty, OnlyIfReduced);
2169 }
2170
2171 Constant *ConstantExpr::getFPToUI(Constant *C, Type *Ty, bool OnlyIfReduced) {
2172 #ifndef NDEBUG
2173   bool fromVec = isa<VectorType>(C->getType());
2174   bool toVec = isa<VectorType>(Ty);
2175 #endif
2176   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
2177   assert(C->getType()->isFPOrFPVectorTy() && Ty->isIntOrIntVectorTy() &&
2178          "This is an illegal floating point to uint cast!");
2179   return getFoldedCast(Instruction::FPToUI, C, Ty, OnlyIfReduced);
2180 }
2181
2182 Constant *ConstantExpr::getFPToSI(Constant *C, Type *Ty, bool OnlyIfReduced) {
2183 #ifndef NDEBUG
2184   bool fromVec = isa<VectorType>(C->getType());
2185   bool toVec = isa<VectorType>(Ty);
2186 #endif
2187   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
2188   assert(C->getType()->isFPOrFPVectorTy() && Ty->isIntOrIntVectorTy() &&
2189          "This is an illegal floating point to sint cast!");
2190   return getFoldedCast(Instruction::FPToSI, C, Ty, OnlyIfReduced);
2191 }
2192
2193 Constant *ConstantExpr::getPtrToInt(Constant *C, Type *DstTy,
2194                                     bool OnlyIfReduced) {
2195   assert(C->getType()->isPtrOrPtrVectorTy() &&
2196          "PtrToInt source must be pointer or pointer vector");
2197   assert(DstTy->isIntOrIntVectorTy() &&
2198          "PtrToInt destination must be integer or integer vector");
2199   assert(isa<VectorType>(C->getType()) == isa<VectorType>(DstTy));
2200   if (isa<VectorType>(C->getType()))
2201     assert(cast<FixedVectorType>(C->getType())->getNumElements() ==
2202                cast<FixedVectorType>(DstTy)->getNumElements() &&
2203            "Invalid cast between a different number of vector elements");
2204   return getFoldedCast(Instruction::PtrToInt, C, DstTy, OnlyIfReduced);
2205 }
2206
2207 Constant *ConstantExpr::getIntToPtr(Constant *C, Type *DstTy,
2208                                     bool OnlyIfReduced) {
2209   assert(C->getType()->isIntOrIntVectorTy() &&
2210          "IntToPtr source must be integer or integer vector");
2211   assert(DstTy->isPtrOrPtrVectorTy() &&
2212          "IntToPtr destination must be a pointer or pointer vector");
2213   assert(isa<VectorType>(C->getType()) == isa<VectorType>(DstTy));
2214   if (isa<VectorType>(C->getType()))
2215     assert(cast<VectorType>(C->getType())->getElementCount() ==
2216                cast<VectorType>(DstTy)->getElementCount() &&
2217            "Invalid cast between a different number of vector elements");
2218   return getFoldedCast(Instruction::IntToPtr, C, DstTy, OnlyIfReduced);
2219 }
2220
2221 Constant *ConstantExpr::getBitCast(Constant *C, Type *DstTy,
2222                                    bool OnlyIfReduced) {
2223   assert(CastInst::castIsValid(Instruction::BitCast, C, DstTy) &&
2224          "Invalid constantexpr bitcast!");
2225
2226   // It is common to ask for a bitcast of a value to its own type, handle this
2227   // speedily.
2228   if (C->getType() == DstTy) return C;
2229
2230   return getFoldedCast(Instruction::BitCast, C, DstTy, OnlyIfReduced);
2231 }
2232
2233 Constant *ConstantExpr::getAddrSpaceCast(Constant *C, Type *DstTy,
2234                                          bool OnlyIfReduced) {
2235   assert(CastInst::castIsValid(Instruction::AddrSpaceCast, C, DstTy) &&
2236          "Invalid constantexpr addrspacecast!");
2237
2238   // Canonicalize addrspacecasts between different pointer types by first
2239   // bitcasting the pointer type and then converting the address space.
2240   PointerType *SrcScalarTy = cast<PointerType>(C->getType()->getScalarType());
2241   PointerType *DstScalarTy = cast<PointerType>(DstTy->getScalarType());
2242   if (!SrcScalarTy->hasSameElementTypeAs(DstScalarTy)) {
2243     Type *MidTy = PointerType::getWithSamePointeeType(
2244         DstScalarTy, SrcScalarTy->getAddressSpace());
2245     if (VectorType *VT = dyn_cast<VectorType>(DstTy)) {
2246       // Handle vectors of pointers.
2247       MidTy = FixedVectorType::get(MidTy,
2248                                    cast<FixedVectorType>(VT)->getNumElements());
2249     }
2250     C = getBitCast(C, MidTy);
2251   }
2252   return getFoldedCast(Instruction::AddrSpaceCast, C, DstTy, OnlyIfReduced);
2253 }
2254
2255 Constant *ConstantExpr::get(unsigned Opcode, Constant *C, unsigned Flags,
2256                             Type *OnlyIfReducedTy) {
2257   // Check the operands for consistency first.
2258   assert(Instruction::isUnaryOp(Opcode) &&
2259          "Invalid opcode in unary constant expression");
2260
2261 #ifndef NDEBUG
2262   switch (Opcode) {
2263   case Instruction::FNeg:
2264     assert(C->getType()->isFPOrFPVectorTy() &&
2265            "Tried to create a floating-point operation on a "
2266            "non-floating-point type!");
2267     break;
2268   default:
2269     break;
2270   }
2271 #endif
2272
2273   if (Constant *FC = ConstantFoldUnaryInstruction(Opcode, C))
2274     return FC;
2275
2276   if (OnlyIfReducedTy == C->getType())
2277     return nullptr;
2278
2279   Constant *ArgVec[] = { C };
2280   ConstantExprKeyType Key(Opcode, ArgVec, 0, Flags);
2281
2282   LLVMContextImpl *pImpl = C->getContext().pImpl;
2283   return pImpl->ExprConstants.getOrCreate(C->getType(), Key);
2284 }
2285
2286 Constant *ConstantExpr::get(unsigned Opcode, Constant *C1, Constant *C2,
2287                             unsigned Flags, Type *OnlyIfReducedTy) {
2288   // Check the operands for consistency first.
2289   assert(Instruction::isBinaryOp(Opcode) &&
2290          "Invalid opcode in binary constant expression");
2291   assert(C1->getType() == C2->getType() &&
2292          "Operand types in binary constant expression should match");
2293
2294 #ifndef NDEBUG
2295   switch (Opcode) {
2296   case Instruction::Add:
2297   case Instruction::Sub:
2298   case Instruction::Mul:
2299   case Instruction::UDiv:
2300   case Instruction::SDiv:
2301   case Instruction::URem:
2302   case Instruction::SRem:
2303     assert(C1->getType()->isIntOrIntVectorTy() &&
2304            "Tried to create an integer operation on a non-integer type!");
2305     break;
2306   case Instruction::FAdd:
2307   case Instruction::FSub:
2308   case Instruction::FMul:
2309   case Instruction::FDiv:
2310   case Instruction::FRem:
2311     assert(C1->getType()->isFPOrFPVectorTy() &&
2312            "Tried to create a floating-point operation on a "
2313            "non-floating-point type!");
2314     break;
2315   case Instruction::And:
2316   case Instruction::Or:
2317   case Instruction::Xor:
2318     assert(C1->getType()->isIntOrIntVectorTy() &&
2319            "Tried to create a logical operation on a non-integral type!");
2320     break;
2321   case Instruction::Shl:
2322   case Instruction::LShr:
2323   case Instruction::AShr:
2324     assert(C1->getType()->isIntOrIntVectorTy() &&
2325            "Tried to create a shift operation on a non-integer type!");
2326     break;
2327   default:
2328     break;
2329   }
2330 #endif
2331
2332   if (Constant *FC = ConstantFoldBinaryInstruction(Opcode, C1, C2))
2333     return FC;
2334
2335   if (OnlyIfReducedTy == C1->getType())
2336     return nullptr;
2337
2338   Constant *ArgVec[] = { C1, C2 };
2339   ConstantExprKeyType Key(Opcode, ArgVec, 0, Flags);
2340
2341   LLVMContextImpl *pImpl = C1->getContext().pImpl;
2342   return pImpl->ExprConstants.getOrCreate(C1->getType(), Key);
2343 }
2344
2345 Constant *ConstantExpr::getSizeOf(Type* Ty) {
2346   // sizeof is implemented as: (i64) gep (Ty*)null, 1
2347   // Note that a non-inbounds gep is used, as null isn't within any object.
2348   Constant *GEPIdx = ConstantInt::get(Type::getInt32Ty(Ty->getContext()), 1);
2349   Constant *GEP = getGetElementPtr(
2350       Ty, Constant::getNullValue(PointerType::getUnqual(Ty)), GEPIdx);
2351   return getPtrToInt(GEP,
2352                      Type::getInt64Ty(Ty->getContext()));
2353 }
2354
2355 Constant *ConstantExpr::getAlignOf(Type* Ty) {
2356   // alignof is implemented as: (i64) gep ({i1,Ty}*)null, 0, 1
2357   // Note that a non-inbounds gep is used, as null isn't within any object.
2358   Type *AligningTy = StructType::get(Type::getInt1Ty(Ty->getContext()), Ty);
2359   Constant *NullPtr = Constant::getNullValue(AligningTy->getPointerTo(0));
2360   Constant *Zero = ConstantInt::get(Type::getInt64Ty(Ty->getContext()), 0);
2361   Constant *One = ConstantInt::get(Type::getInt32Ty(Ty->getContext()), 1);
2362   Constant *Indices[2] = { Zero, One };
2363   Constant *GEP = getGetElementPtr(AligningTy, NullPtr, Indices);
2364   return getPtrToInt(GEP,
2365                      Type::getInt64Ty(Ty->getContext()));
2366 }
2367
2368 Constant *ConstantExpr::getOffsetOf(StructType* STy, unsigned FieldNo) {
2369   return getOffsetOf(STy, ConstantInt::get(Type::getInt32Ty(STy->getContext()),
2370                                            FieldNo));
2371 }
2372
2373 Constant *ConstantExpr::getOffsetOf(Type* Ty, Constant *FieldNo) {
2374   // offsetof is implemented as: (i64) gep (Ty*)null, 0, FieldNo
2375   // Note that a non-inbounds gep is used, as null isn't within any object.
2376   Constant *GEPIdx[] = {
2377     ConstantInt::get(Type::getInt64Ty(Ty->getContext()), 0),
2378     FieldNo
2379   };
2380   Constant *GEP = getGetElementPtr(
2381       Ty, Constant::getNullValue(PointerType::getUnqual(Ty)), GEPIdx);
2382   return getPtrToInt(GEP,
2383                      Type::getInt64Ty(Ty->getContext()));
2384 }
2385
2386 Constant *ConstantExpr::getCompare(unsigned short Predicate, Constant *C1,
2387                                    Constant *C2, bool OnlyIfReduced) {
2388   assert(C1->getType() == C2->getType() && "Op types should be identical!");
2389
2390   switch (Predicate) {
2391   default: llvm_unreachable("Invalid CmpInst predicate");
2392   case CmpInst::FCMP_FALSE: case CmpInst::FCMP_OEQ: case CmpInst::FCMP_OGT:
2393   case CmpInst::FCMP_OGE:   case CmpInst::FCMP_OLT: case CmpInst::FCMP_OLE:
2394   case CmpInst::FCMP_ONE:   case CmpInst::FCMP_ORD: case CmpInst::FCMP_UNO:
2395   case CmpInst::FCMP_UEQ:   case CmpInst::FCMP_UGT: case CmpInst::FCMP_UGE:
2396   case CmpInst::FCMP_ULT:   case CmpInst::FCMP_ULE: case CmpInst::FCMP_UNE:
2397   case CmpInst::FCMP_TRUE:
2398     return getFCmp(Predicate, C1, C2, OnlyIfReduced);
2399
2400   case CmpInst::ICMP_EQ:  case CmpInst::ICMP_NE:  case CmpInst::ICMP_UGT:
2401   case CmpInst::ICMP_UGE: case CmpInst::ICMP_ULT: case CmpInst::ICMP_ULE:
2402   case CmpInst::ICMP_SGT: case CmpInst::ICMP_SGE: case CmpInst::ICMP_SLT:
2403   case CmpInst::ICMP_SLE:
2404     return getICmp(Predicate, C1, C2, OnlyIfReduced);
2405   }
2406 }
2407
2408 Constant *ConstantExpr::getSelect(Constant *C, Constant *V1, Constant *V2,
2409                                   Type *OnlyIfReducedTy) {
2410   assert(!SelectInst::areInvalidOperands(C, V1, V2)&&"Invalid select operands");
2411
2412   if (Constant *SC = ConstantFoldSelectInstruction(C, V1, V2))
2413     return SC;        // Fold common cases
2414
2415   if (OnlyIfReducedTy == V1->getType())
2416     return nullptr;
2417
2418   Constant *ArgVec[] = { C, V1, V2 };
2419   ConstantExprKeyType Key(Instruction::Select, ArgVec);
2420
2421   LLVMContextImpl *pImpl = C->getContext().pImpl;
2422   return pImpl->ExprConstants.getOrCreate(V1->getType(), Key);
2423 }
2424
2425 Constant *ConstantExpr::getGetElementPtr(Type *Ty, Constant *C,
2426                                          ArrayRef<Value *> Idxs, bool InBounds,
2427                                          Optional<unsigned> InRangeIndex,
2428                                          Type *OnlyIfReducedTy) {
2429   PointerType *OrigPtrTy = cast<PointerType>(C->getType()->getScalarType());
2430   assert(Ty && "Must specify element type");
2431   assert(OrigPtrTy->isOpaqueOrPointeeTypeMatches(Ty));
2432
2433   if (Constant *FC =
2434           ConstantFoldGetElementPtr(Ty, C, InBounds, InRangeIndex, Idxs))
2435     return FC;          // Fold a few common cases.
2436
2437   // Get the result type of the getelementptr!
2438   Type *DestTy = GetElementPtrInst::getIndexedType(Ty, Idxs);
2439   assert(DestTy && "GEP indices invalid!");
2440   unsigned AS = OrigPtrTy->getAddressSpace();
2441   Type *ReqTy = OrigPtrTy->isOpaque()
2442       ? PointerType::get(OrigPtrTy->getContext(), AS)
2443       : DestTy->getPointerTo(AS);
2444
2445   auto EltCount = ElementCount::getFixed(0);
2446   if (VectorType *VecTy = dyn_cast<VectorType>(C->getType()))
2447     EltCount = VecTy->getElementCount();
2448   else
2449     for (auto Idx : Idxs)
2450       if (VectorType *VecTy = dyn_cast<VectorType>(Idx->getType()))
2451         EltCount = VecTy->getElementCount();
2452
2453   if (EltCount.isNonZero())
2454     ReqTy = VectorType::get(ReqTy, EltCount);
2455
2456   if (OnlyIfReducedTy == ReqTy)
2457     return nullptr;
2458
2459   // Look up the constant in the table first to ensure uniqueness
2460   std::vector<Constant*> ArgVec;
2461   ArgVec.reserve(1 + Idxs.size());
2462   ArgVec.push_back(C);
2463   auto GTI = gep_type_begin(Ty, Idxs), GTE = gep_type_end(Ty, Idxs);
2464   for (; GTI != GTE; ++GTI) {
2465     auto *Idx = cast<Constant>(GTI.getOperand());
2466     assert(
2467         (!isa<VectorType>(Idx->getType()) ||
2468          cast<VectorType>(Idx->getType())->getElementCount() == EltCount) &&
2469         "getelementptr index type missmatch");
2470
2471     if (GTI.isStruct() && Idx->getType()->isVectorTy()) {
2472       Idx = Idx->getSplatValue();
2473     } else if (GTI.isSequential() && EltCount.isNonZero() &&
2474                !Idx->getType()->isVectorTy()) {
2475       Idx = ConstantVector::getSplat(EltCount, Idx);
2476     }
2477     ArgVec.push_back(Idx);
2478   }
2479
2480   unsigned SubClassOptionalData = InBounds ? GEPOperator::IsInBounds : 0;
2481   if (InRangeIndex && *InRangeIndex < 63)
2482     SubClassOptionalData |= (*InRangeIndex + 1) << 1;
2483   const ConstantExprKeyType Key(Instruction::GetElementPtr, ArgVec, 0,
2484                                 SubClassOptionalData, None, None, Ty);
2485
2486   LLVMContextImpl *pImpl = C->getContext().pImpl;
2487   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
2488 }
2489
2490 Constant *ConstantExpr::getICmp(unsigned short pred, Constant *LHS,
2491                                 Constant *RHS, bool OnlyIfReduced) {
2492   assert(LHS->getType() == RHS->getType());
2493   assert(CmpInst::isIntPredicate((CmpInst::Predicate)pred) &&
2494          "Invalid ICmp Predicate");
2495
2496   if (Constant *FC = ConstantFoldCompareInstruction(pred, LHS, RHS))
2497     return FC;          // Fold a few common cases...
2498
2499   if (OnlyIfReduced)
2500     return nullptr;
2501
2502   // Look up the constant in the table first to ensure uniqueness
2503   Constant *ArgVec[] = { LHS, RHS };
2504   // Get the key type with both the opcode and predicate
2505   const ConstantExprKeyType Key(Instruction::ICmp, ArgVec, pred);
2506
2507   Type *ResultTy = Type::getInt1Ty(LHS->getContext());
2508   if (VectorType *VT = dyn_cast<VectorType>(LHS->getType()))
2509     ResultTy = VectorType::get(ResultTy, VT->getElementCount());
2510
2511   LLVMContextImpl *pImpl = LHS->getType()->getContext().pImpl;
2512   return pImpl->ExprConstants.getOrCreate(ResultTy, Key);
2513 }
2514
2515 Constant *ConstantExpr::getFCmp(unsigned short pred, Constant *LHS,
2516                                 Constant *RHS, bool OnlyIfReduced) {
2517   assert(LHS->getType() == RHS->getType());
2518   assert(CmpInst::isFPPredicate((CmpInst::Predicate)pred) &&
2519          "Invalid FCmp Predicate");
2520
2521   if (Constant *FC = ConstantFoldCompareInstruction(pred, LHS, RHS))
2522     return FC;          // Fold a few common cases...
2523
2524   if (OnlyIfReduced)
2525     return nullptr;
2526
2527   // Look up the constant in the table first to ensure uniqueness
2528   Constant *ArgVec[] = { LHS, RHS };
2529   // Get the key type with both the opcode and predicate
2530   const ConstantExprKeyType Key(Instruction::FCmp, ArgVec, pred);
2531
2532   Type *ResultTy = Type::getInt1Ty(LHS->getContext());
2533   if (VectorType *VT = dyn_cast<VectorType>(LHS->getType()))
2534     ResultTy = VectorType::get(ResultTy, VT->getElementCount());
2535
2536   LLVMContextImpl *pImpl = LHS->getType()->getContext().pImpl;
2537   return pImpl->ExprConstants.getOrCreate(ResultTy, Key);
2538 }
2539
2540 Constant *ConstantExpr::getExtractElement(Constant *Val, Constant *Idx,
2541                                           Type *OnlyIfReducedTy) {
2542   assert(Val->getType()->isVectorTy() &&
2543          "Tried to create extractelement operation on non-vector type!");
2544   assert(Idx->getType()->isIntegerTy() &&
2545          "Extractelement index must be an integer type!");
2546
2547   if (Constant *FC = ConstantFoldExtractElementInstruction(Val, Idx))
2548     return FC;          // Fold a few common cases.
2549
2550   Type *ReqTy = cast<VectorType>(Val->getType())->getElementType();
2551   if (OnlyIfReducedTy == ReqTy)
2552     return nullptr;
2553
2554   // Look up the constant in the table first to ensure uniqueness
2555   Constant *ArgVec[] = { Val, Idx };
2556   const ConstantExprKeyType Key(Instruction::ExtractElement, ArgVec);
2557
2558   LLVMContextImpl *pImpl = Val->getContext().pImpl;
2559   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
2560 }
2561
2562 Constant *ConstantExpr::getInsertElement(Constant *Val, Constant *Elt,
2563                                          Constant *Idx, Type *OnlyIfReducedTy) {
2564   assert(Val->getType()->isVectorTy() &&
2565          "Tried to create insertelement operation on non-vector type!");
2566   assert(Elt->getType() == cast<VectorType>(Val->getType())->getElementType() &&
2567          "Insertelement types must match!");
2568   assert(Idx->getType()->isIntegerTy() &&
2569          "Insertelement index must be i32 type!");
2570
2571   if (Constant *FC = ConstantFoldInsertElementInstruction(Val, Elt, Idx))
2572     return FC;          // Fold a few common cases.
2573
2574   if (OnlyIfReducedTy == Val->getType())
2575     return nullptr;
2576
2577   // Look up the constant in the table first to ensure uniqueness
2578   Constant *ArgVec[] = { Val, Elt, Idx };
2579   const ConstantExprKeyType Key(Instruction::InsertElement, ArgVec);
2580
2581   LLVMContextImpl *pImpl = Val->getContext().pImpl;
2582   return pImpl->ExprConstants.getOrCreate(Val->getType(), Key);
2583 }
2584
2585 Constant *ConstantExpr::getShuffleVector(Constant *V1, Constant *V2,
2586                                          ArrayRef<int> Mask,
2587                                          Type *OnlyIfReducedTy) {
2588   assert(ShuffleVectorInst::isValidOperands(V1, V2, Mask) &&
2589          "Invalid shuffle vector constant expr operands!");
2590
2591   if (Constant *FC = ConstantFoldShuffleVectorInstruction(V1, V2, Mask))
2592     return FC;          // Fold a few common cases.
2593
2594   unsigned NElts = Mask.size();
2595   auto V1VTy = cast<VectorType>(V1->getType());
2596   Type *EltTy = V1VTy->getElementType();
2597   bool TypeIsScalable = isa<ScalableVectorType>(V1VTy);
2598   Type *ShufTy = VectorType::get(EltTy, NElts, TypeIsScalable);
2599
2600   if (OnlyIfReducedTy == ShufTy)
2601     return nullptr;
2602
2603   // Look up the constant in the table first to ensure uniqueness
2604   Constant *ArgVec[] = {V1, V2};
2605   ConstantExprKeyType Key(Instruction::ShuffleVector, ArgVec, 0, 0, None, Mask);
2606
2607   LLVMContextImpl *pImpl = ShufTy->getContext().pImpl;
2608   return pImpl->ExprConstants.getOrCreate(ShufTy, Key);
2609 }
2610
2611 Constant *ConstantExpr::getInsertValue(Constant *Agg, Constant *Val,
2612                                        ArrayRef<unsigned> Idxs,
2613                                        Type *OnlyIfReducedTy) {
2614   assert(Agg->getType()->isFirstClassType() &&
2615          "Non-first-class type for constant insertvalue expression");
2616
2617   assert(ExtractValueInst::getIndexedType(Agg->getType(),
2618                                           Idxs) == Val->getType() &&
2619          "insertvalue indices invalid!");
2620   Type *ReqTy = Val->getType();
2621
2622   if (Constant *FC = ConstantFoldInsertValueInstruction(Agg, Val, Idxs))
2623     return FC;
2624
2625   if (OnlyIfReducedTy == ReqTy)
2626     return nullptr;
2627
2628   Constant *ArgVec[] = { Agg, Val };
2629   const ConstantExprKeyType Key(Instruction::InsertValue, ArgVec, 0, 0, Idxs);
2630
2631   LLVMContextImpl *pImpl = Agg->getContext().pImpl;
2632   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
2633 }
2634
2635 Constant *ConstantExpr::getExtractValue(Constant *Agg, ArrayRef<unsigned> Idxs,
2636                                         Type *OnlyIfReducedTy) {
2637   assert(Agg->getType()->isFirstClassType() &&
2638          "Tried to create extractelement operation on non-first-class type!");
2639
2640   Type *ReqTy = ExtractValueInst::getIndexedType(Agg->getType(), Idxs);
2641   (void)ReqTy;
2642   assert(ReqTy && "extractvalue indices invalid!");
2643
2644   assert(Agg->getType()->isFirstClassType() &&
2645          "Non-first-class type for constant extractvalue expression");
2646   if (Constant *FC = ConstantFoldExtractValueInstruction(Agg, Idxs))
2647     return FC;
2648
2649   if (OnlyIfReducedTy == ReqTy)
2650     return nullptr;
2651
2652   Constant *ArgVec[] = { Agg };
2653   const ConstantExprKeyType Key(Instruction::ExtractValue, ArgVec, 0, 0, Idxs);
2654
2655   LLVMContextImpl *pImpl = Agg->getContext().pImpl;
2656   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
2657 }
2658
2659 Constant *ConstantExpr::getNeg(Constant *C, bool HasNUW, bool HasNSW) {
2660   assert(C->getType()->isIntOrIntVectorTy() &&
2661          "Cannot NEG a nonintegral value!");
2662   return getSub(ConstantFP::getZeroValueForNegation(C->getType()),
2663                 C, HasNUW, HasNSW);
2664 }
2665
2666 Constant *ConstantExpr::getFNeg(Constant *C) {
2667   assert(C->getType()->isFPOrFPVectorTy() &&
2668          "Cannot FNEG a non-floating-point value!");
2669   return get(Instruction::FNeg, C);
2670 }
2671
2672 Constant *ConstantExpr::getNot(Constant *C) {
2673   assert(C->getType()->isIntOrIntVectorTy() &&
2674          "Cannot NOT a nonintegral value!");
2675   return get(Instruction::Xor, C, Constant::getAllOnesValue(C->getType()));
2676 }
2677
2678 Constant *ConstantExpr::getAdd(Constant *C1, Constant *C2,
2679                                bool HasNUW, bool HasNSW) {
2680   unsigned Flags = (HasNUW ? OverflowingBinaryOperator::NoUnsignedWrap : 0) |
2681                    (HasNSW ? OverflowingBinaryOperator::NoSignedWrap   : 0);
2682   return get(Instruction::Add, C1, C2, Flags);
2683 }
2684
2685 Constant *ConstantExpr::getFAdd(Constant *C1, Constant *C2) {
2686   return get(Instruction::FAdd, C1, C2);
2687 }
2688
2689 Constant *ConstantExpr::getSub(Constant *C1, Constant *C2,
2690                                bool HasNUW, bool HasNSW) {
2691   unsigned Flags = (HasNUW ? OverflowingBinaryOperator::NoUnsignedWrap : 0) |
2692                    (HasNSW ? OverflowingBinaryOperator::NoSignedWrap   : 0);
2693   return get(Instruction::Sub, C1, C2, Flags);
2694 }
2695
2696 Constant *ConstantExpr::getFSub(Constant *C1, Constant *C2) {
2697   return get(Instruction::FSub, C1, C2);
2698 }
2699
2700 Constant *ConstantExpr::getMul(Constant *C1, Constant *C2,
2701                                bool HasNUW, bool HasNSW) {
2702   unsigned Flags = (HasNUW ? OverflowingBinaryOperator::NoUnsignedWrap : 0) |
2703                    (HasNSW ? OverflowingBinaryOperator::NoSignedWrap   : 0);
2704   return get(Instruction::Mul, C1, C2, Flags);
2705 }
2706
2707 Constant *ConstantExpr::getFMul(Constant *C1, Constant *C2) {
2708   return get(Instruction::FMul, C1, C2);
2709 }
2710
2711 Constant *ConstantExpr::getUDiv(Constant *C1, Constant *C2, bool isExact) {
2712   return get(Instruction::UDiv, C1, C2,
2713              isExact ? PossiblyExactOperator::IsExact : 0);
2714 }
2715
2716 Constant *ConstantExpr::getSDiv(Constant *C1, Constant *C2, bool isExact) {
2717   return get(Instruction::SDiv, C1, C2,
2718              isExact ? PossiblyExactOperator::IsExact : 0);
2719 }
2720
2721 Constant *ConstantExpr::getFDiv(Constant *C1, Constant *C2) {
2722   return get(Instruction::FDiv, C1, C2);
2723 }
2724
2725 Constant *ConstantExpr::getURem(Constant *C1, Constant *C2) {
2726   return get(Instruction::URem, C1, C2);
2727 }
2728
2729 Constant *ConstantExpr::getSRem(Constant *C1, Constant *C2) {
2730   return get(Instruction::SRem, C1, C2);
2731 }
2732
2733 Constant *ConstantExpr::getFRem(Constant *C1, Constant *C2) {
2734   return get(Instruction::FRem, C1, C2);
2735 }
2736
2737 Constant *ConstantExpr::getAnd(Constant *C1, Constant *C2) {
2738   return get(Instruction::And, C1, C2);
2739 }
2740
2741 Constant *ConstantExpr::getOr(Constant *C1, Constant *C2) {
2742   return get(Instruction::Or, C1, C2);
2743 }
2744
2745 Constant *ConstantExpr::getXor(Constant *C1, Constant *C2) {
2746   return get(Instruction::Xor, C1, C2);
2747 }
2748
2749 Constant *ConstantExpr::getUMin(Constant *C1, Constant *C2) {
2750   Constant *Cmp = ConstantExpr::getICmp(CmpInst::ICMP_ULT, C1, C2);
2751   return getSelect(Cmp, C1, C2);
2752 }
2753
2754 Constant *ConstantExpr::getShl(Constant *C1, Constant *C2,
2755                                bool HasNUW, bool HasNSW) {
2756   unsigned Flags = (HasNUW ? OverflowingBinaryOperator::NoUnsignedWrap : 0) |
2757                    (HasNSW ? OverflowingBinaryOperator::NoSignedWrap   : 0);
2758   return get(Instruction::Shl, C1, C2, Flags);
2759 }
2760
2761 Constant *ConstantExpr::getLShr(Constant *C1, Constant *C2, bool isExact) {
2762   return get(Instruction::LShr, C1, C2,
2763              isExact ? PossiblyExactOperator::IsExact : 0);
2764 }
2765
2766 Constant *ConstantExpr::getAShr(Constant *C1, Constant *C2, bool isExact) {
2767   return get(Instruction::AShr, C1, C2,
2768              isExact ? PossiblyExactOperator::IsExact : 0);
2769 }
2770
2771 Constant *ConstantExpr::getExactLogBase2(Constant *C) {
2772   Type *Ty = C->getType();
2773   const APInt *IVal;
2774   if (match(C, m_APInt(IVal)) && IVal->isPowerOf2())
2775     return ConstantInt::get(Ty, IVal->logBase2());
2776
2777   // FIXME: We can extract pow of 2 of splat constant for scalable vectors.
2778   auto *VecTy = dyn_cast<FixedVectorType>(Ty);
2779   if (!VecTy)
2780     return nullptr;
2781
2782   SmallVector<Constant *, 4> Elts;
2783   for (unsigned I = 0, E = VecTy->getNumElements(); I != E; ++I) {
2784     Constant *Elt = C->getAggregateElement(I);
2785     if (!Elt)
2786       return nullptr;
2787     // Note that log2(iN undef) is *NOT* iN undef, because log2(iN undef) u< N.
2788     if (isa<UndefValue>(Elt)) {
2789       Elts.push_back(Constant::getNullValue(Ty->getScalarType()));
2790       continue;
2791     }
2792     if (!match(Elt, m_APInt(IVal)) || !IVal->isPowerOf2())
2793       return nullptr;
2794     Elts.push_back(ConstantInt::get(Ty->getScalarType(), IVal->logBase2()));
2795   }
2796
2797   return ConstantVector::get(Elts);
2798 }
2799
2800 Constant *ConstantExpr::getBinOpIdentity(unsigned Opcode, Type *Ty,
2801                                          bool AllowRHSConstant) {
2802   assert(Instruction::isBinaryOp(Opcode) && "Only binops allowed");
2803
2804   // Commutative opcodes: it does not matter if AllowRHSConstant is set.
2805   if (Instruction::isCommutative(Opcode)) {
2806     switch (Opcode) {
2807       case Instruction::Add: // X + 0 = X
2808       case Instruction::Or:  // X | 0 = X
2809       case Instruction::Xor: // X ^ 0 = X
2810         return Constant::getNullValue(Ty);
2811       case Instruction::Mul: // X * 1 = X
2812         return ConstantInt::get(Ty, 1);
2813       case Instruction::And: // X & -1 = X
2814         return Constant::getAllOnesValue(Ty);
2815       case Instruction::FAdd: // X + -0.0 = X
2816         // TODO: If the fadd has 'nsz', should we return +0.0?
2817         return ConstantFP::getNegativeZero(Ty);
2818       case Instruction::FMul: // X * 1.0 = X
2819         return ConstantFP::get(Ty, 1.0);
2820       default:
2821         llvm_unreachable("Every commutative binop has an identity constant");
2822     }
2823   }
2824
2825   // Non-commutative opcodes: AllowRHSConstant must be set.
2826   if (!AllowRHSConstant)
2827     return nullptr;
2828
2829   switch (Opcode) {
2830     case Instruction::Sub:  // X - 0 = X
2831     case Instruction::Shl:  // X << 0 = X
2832     case Instruction::LShr: // X >>u 0 = X
2833     case Instruction::AShr: // X >> 0 = X
2834     case Instruction::FSub: // X - 0.0 = X
2835       return Constant::getNullValue(Ty);
2836     case Instruction::SDiv: // X / 1 = X
2837     case Instruction::UDiv: // X /u 1 = X
2838       return ConstantInt::get(Ty, 1);
2839     case Instruction::FDiv: // X / 1.0 = X
2840       return ConstantFP::get(Ty, 1.0);
2841     default:
2842       return nullptr;
2843   }
2844 }
2845
2846 Constant *ConstantExpr::getBinOpAbsorber(unsigned Opcode, Type *Ty) {
2847   switch (Opcode) {
2848   default:
2849     // Doesn't have an absorber.
2850     return nullptr;
2851
2852   case Instruction::Or:
2853     return Constant::getAllOnesValue(Ty);
2854
2855   case Instruction::And:
2856   case Instruction::Mul:
2857     return Constant::getNullValue(Ty);
2858   }
2859 }
2860
2861 /// Remove the constant from the constant table.
2862 void ConstantExpr::destroyConstantImpl() {
2863   getType()->getContext().pImpl->ExprConstants.remove(this);
2864 }
2865
2866 const char *ConstantExpr::getOpcodeName() const {
2867   return Instruction::getOpcodeName(getOpcode());
2868 }
2869
2870 GetElementPtrConstantExpr::GetElementPtrConstantExpr(
2871     Type *SrcElementTy, Constant *C, ArrayRef<Constant *> IdxList, Type *DestTy)
2872     : ConstantExpr(DestTy, Instruction::GetElementPtr,
2873                    OperandTraits<GetElementPtrConstantExpr>::op_end(this) -
2874                        (IdxList.size() + 1),
2875                    IdxList.size() + 1),
2876       SrcElementTy(SrcElementTy),
2877       ResElementTy(GetElementPtrInst::getIndexedType(SrcElementTy, IdxList)) {
2878   Op<0>() = C;
2879   Use *OperandList = getOperandList();
2880   for (unsigned i = 0, E = IdxList.size(); i != E; ++i)
2881     OperandList[i+1] = IdxList[i];
2882 }
2883
2884 Type *GetElementPtrConstantExpr::getSourceElementType() const {
2885   return SrcElementTy;
2886 }
2887
2888 Type *GetElementPtrConstantExpr::getResultElementType() const {
2889   return ResElementTy;
2890 }
2891
2892 //===----------------------------------------------------------------------===//
2893 //                       ConstantData* implementations
2894
2895 Type *ConstantDataSequential::getElementType() const {
2896   if (ArrayType *ATy = dyn_cast<ArrayType>(getType()))
2897     return ATy->getElementType();
2898   return cast<VectorType>(getType())->getElementType();
2899 }
2900
2901 StringRef ConstantDataSequential::getRawDataValues() const {
2902   return StringRef(DataElements, getNumElements()*getElementByteSize());
2903 }
2904
2905 bool ConstantDataSequential::isElementTypeCompatible(Type *Ty) {
2906   if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() || Ty->isDoubleTy())
2907     return true;
2908   if (auto *IT = dyn_cast<IntegerType>(Ty)) {
2909     switch (IT->getBitWidth()) {
2910     case 8:
2911     case 16:
2912     case 32:
2913     case 64:
2914       return true;
2915     default: break;
2916     }
2917   }
2918   return false;
2919 }
2920
2921 unsigned ConstantDataSequential::getNumElements() const {
2922   if (ArrayType *AT = dyn_cast<ArrayType>(getType()))
2923     return AT->getNumElements();
2924   return cast<FixedVectorType>(getType())->getNumElements();
2925 }
2926
2927
2928 uint64_t ConstantDataSequential::getElementByteSize() const {
2929   return getElementType()->getPrimitiveSizeInBits()/8;
2930 }
2931
2932 /// Return the start of the specified element.
2933 const char *ConstantDataSequential::getElementPointer(unsigned Elt) const {
2934   assert(Elt < getNumElements() && "Invalid Elt");
2935   return DataElements+Elt*getElementByteSize();
2936 }
2937
2938
2939 /// Return true if the array is empty or all zeros.
2940 static bool isAllZeros(StringRef Arr) {
2941   for (char I : Arr)
2942     if (I != 0)
2943       return false;
2944   return true;
2945 }
2946
2947 /// This is the underlying implementation of all of the
2948 /// ConstantDataSequential::get methods.  They all thunk down to here, providing
2949 /// the correct element type.  We take the bytes in as a StringRef because
2950 /// we *want* an underlying "char*" to avoid TBAA type punning violations.
2951 Constant *ConstantDataSequential::getImpl(StringRef Elements, Type *Ty) {
2952 #ifndef NDEBUG
2953   if (ArrayType *ATy = dyn_cast<ArrayType>(Ty))
2954     assert(isElementTypeCompatible(ATy->getElementType()));
2955   else
2956     assert(isElementTypeCompatible(cast<VectorType>(Ty)->getElementType()));
2957 #endif
2958   // If the elements are all zero or there are no elements, return a CAZ, which
2959   // is more dense and canonical.
2960   if (isAllZeros(Elements))
2961     return ConstantAggregateZero::get(Ty);
2962
2963   // Do a lookup to see if we have already formed one of these.
2964   auto &Slot =
2965       *Ty->getContext()
2966            .pImpl->CDSConstants.insert(std::make_pair(Elements, nullptr))
2967            .first;
2968
2969   // The bucket can point to a linked list of different CDS's that have the same
2970   // body but different types.  For example, 0,0,0,1 could be a 4 element array
2971   // of i8, or a 1-element array of i32.  They'll both end up in the same
2972   /// StringMap bucket, linked up by their Next pointers.  Walk the list.
2973   std::unique_ptr<ConstantDataSequential> *Entry = &Slot.second;
2974   for (; *Entry; Entry = &(*Entry)->Next)
2975     if ((*Entry)->getType() == Ty)
2976       return Entry->get();
2977
2978   // Okay, we didn't get a hit.  Create a node of the right class, link it in,
2979   // and return it.
2980   if (isa<ArrayType>(Ty)) {
2981     // Use reset because std::make_unique can't access the constructor.
2982     Entry->reset(new ConstantDataArray(Ty, Slot.first().data()));
2983     return Entry->get();
2984   }
2985
2986   assert(isa<VectorType>(Ty));
2987   // Use reset because std::make_unique can't access the constructor.
2988   Entry->reset(new ConstantDataVector(Ty, Slot.first().data()));
2989   return Entry->get();
2990 }
2991
2992 void ConstantDataSequential::destroyConstantImpl() {
2993   // Remove the constant from the StringMap.
2994   StringMap<std::unique_ptr<ConstantDataSequential>> &CDSConstants =
2995       getType()->getContext().pImpl->CDSConstants;
2996
2997   auto Slot = CDSConstants.find(getRawDataValues());
2998
2999   assert(Slot != CDSConstants.end() && "CDS not found in uniquing table");
3000
3001   std::unique_ptr<ConstantDataSequential> *Entry = &Slot->getValue();
3002
3003   // Remove the entry from the hash table.
3004   if (!(*Entry)->Next) {
3005     // If there is only one value in the bucket (common case) it must be this
3006     // entry, and removing the entry should remove the bucket completely.
3007     assert(Entry->get() == this && "Hash mismatch in ConstantDataSequential");
3008     getContext().pImpl->CDSConstants.erase(Slot);
3009     return;
3010   }
3011
3012   // Otherwise, there are multiple entries linked off the bucket, unlink the
3013   // node we care about but keep the bucket around.
3014   while (true) {
3015     std::unique_ptr<ConstantDataSequential> &Node = *Entry;
3016     assert(Node && "Didn't find entry in its uniquing hash table!");
3017     // If we found our entry, unlink it from the list and we're done.
3018     if (Node.get() == this) {
3019       Node = std::move(Node->Next);
3020       return;
3021     }
3022
3023     Entry = &Node->Next;
3024   }
3025 }
3026
3027 /// getFP() constructors - Return a constant of array type with a float
3028 /// element type taken from argument `ElementType', and count taken from
3029 /// argument `Elts'.  The amount of bits of the contained type must match the
3030 /// number of bits of the type contained in the passed in ArrayRef.
3031 /// (i.e. half or bfloat for 16bits, float for 32bits, double for 64bits) Note
3032 /// that this can return a ConstantAggregateZero object.
3033 Constant *ConstantDataArray::getFP(Type *ElementType, ArrayRef<uint16_t> Elts) {
3034   assert((ElementType->isHalfTy() || ElementType->isBFloatTy()) &&
3035          "Element type is not a 16-bit float type");
3036   Type *Ty = ArrayType::get(ElementType, Elts.size());
3037   const char *Data = reinterpret_cast<const char *>(Elts.data());
3038   return getImpl(StringRef(Data, Elts.size() * 2), Ty);
3039 }
3040 Constant *ConstantDataArray::getFP(Type *ElementType, ArrayRef<uint32_t> Elts) {
3041   assert(ElementType->isFloatTy() && "Element type is not a 32-bit float type");
3042   Type *Ty = ArrayType::get(ElementType, Elts.size());
3043   const char *Data = reinterpret_cast<const char *>(Elts.data());
3044   return getImpl(StringRef(Data, Elts.size() * 4), Ty);
3045 }
3046 Constant *ConstantDataArray::getFP(Type *ElementType, ArrayRef<uint64_t> Elts) {
3047   assert(ElementType->isDoubleTy() &&
3048          "Element type is not a 64-bit float type");
3049   Type *Ty = ArrayType::get(ElementType, Elts.size());
3050   const char *Data = reinterpret_cast<const char *>(Elts.data());
3051   return getImpl(StringRef(Data, Elts.size() * 8), Ty);
3052 }
3053
3054 Constant *ConstantDataArray::getString(LLVMContext &Context,
3055                                        StringRef Str, bool AddNull) {
3056   if (!AddNull) {
3057     const uint8_t *Data = Str.bytes_begin();
3058     return get(Context, makeArrayRef(Data, Str.size()));
3059   }
3060
3061   SmallVector<uint8_t, 64> ElementVals;
3062   ElementVals.append(Str.begin(), Str.end());
3063   ElementVals.push_back(0);
3064   return get(Context, ElementVals);
3065 }
3066
3067 /// get() constructors - Return a constant with vector type with an element
3068 /// count and element type matching the ArrayRef passed in.  Note that this
3069 /// can return a ConstantAggregateZero object.
3070 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<uint8_t> Elts){
3071   auto *Ty = FixedVectorType::get(Type::getInt8Ty(Context), Elts.size());
3072   const char *Data = reinterpret_cast<const char *>(Elts.data());
3073   return getImpl(StringRef(Data, Elts.size() * 1), Ty);
3074 }
3075 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<uint16_t> Elts){
3076   auto *Ty = FixedVectorType::get(Type::getInt16Ty(Context), Elts.size());
3077   const char *Data = reinterpret_cast<const char *>(Elts.data());
3078   return getImpl(StringRef(Data, Elts.size() * 2), Ty);
3079 }
3080 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<uint32_t> Elts){
3081   auto *Ty = FixedVectorType::get(Type::getInt32Ty(Context), Elts.size());
3082   const char *Data = reinterpret_cast<const char *>(Elts.data());
3083   return getImpl(StringRef(Data, Elts.size() * 4), Ty);
3084 }
3085 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<uint64_t> Elts){
3086   auto *Ty = FixedVectorType::get(Type::getInt64Ty(Context), Elts.size());
3087   const char *Data = reinterpret_cast<const char *>(Elts.data());
3088   return getImpl(StringRef(Data, Elts.size() * 8), Ty);
3089 }
3090 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<float> Elts) {
3091   auto *Ty = FixedVectorType::get(Type::getFloatTy(Context), Elts.size());
3092   const char *Data = reinterpret_cast<const char *>(Elts.data());
3093   return getImpl(StringRef(Data, Elts.size() * 4), Ty);
3094 }
3095 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<double> Elts) {
3096   auto *Ty = FixedVectorType::get(Type::getDoubleTy(Context), Elts.size());
3097   const char *Data = reinterpret_cast<const char *>(Elts.data());
3098   return getImpl(StringRef(Data, Elts.size() * 8), Ty);
3099 }
3100
3101 /// getFP() constructors - Return a constant of vector type with a float
3102 /// element type taken from argument `ElementType', and count taken from
3103 /// argument `Elts'.  The amount of bits of the contained type must match the
3104 /// number of bits of the type contained in the passed in ArrayRef.
3105 /// (i.e. half or bfloat for 16bits, float for 32bits, double for 64bits) Note
3106 /// that this can return a ConstantAggregateZero object.
3107 Constant *ConstantDataVector::getFP(Type *ElementType,
3108                                     ArrayRef<uint16_t> Elts) {
3109   assert((ElementType->isHalfTy() || ElementType->isBFloatTy()) &&
3110          "Element type is not a 16-bit float type");
3111   auto *Ty = FixedVectorType::get(ElementType, Elts.size());
3112   const char *Data = reinterpret_cast<const char *>(Elts.data());
3113   return getImpl(StringRef(Data, Elts.size() * 2), Ty);
3114 }
3115 Constant *ConstantDataVector::getFP(Type *ElementType,
3116                                     ArrayRef<uint32_t> Elts) {
3117   assert(ElementType->isFloatTy() && "Element type is not a 32-bit float type");
3118   auto *Ty = FixedVectorType::get(ElementType, Elts.size());
3119   const char *Data = reinterpret_cast<const char *>(Elts.data());
3120   return getImpl(StringRef(Data, Elts.size() * 4), Ty);
3121 }
3122 Constant *ConstantDataVector::getFP(Type *ElementType,
3123                                     ArrayRef<uint64_t> Elts) {
3124   assert(ElementType->isDoubleTy() &&
3125          "Element type is not a 64-bit float type");
3126   auto *Ty = FixedVectorType::get(ElementType, Elts.size());
3127   const char *Data = reinterpret_cast<const char *>(Elts.data());
3128   return getImpl(StringRef(Data, Elts.size() * 8), Ty);
3129 }
3130
3131 Constant *ConstantDataVector::getSplat(unsigned NumElts, Constant *V) {
3132   assert(isElementTypeCompatible(V->getType()) &&
3133          "Element type not compatible with ConstantData");
3134   if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
3135     if (CI->getType()->isIntegerTy(8)) {
3136       SmallVector<uint8_t, 16> Elts(NumElts, CI->getZExtValue());
3137       return get(V->getContext(), Elts);
3138     }
3139     if (CI->getType()->isIntegerTy(16)) {
3140       SmallVector<uint16_t, 16> Elts(NumElts, CI->getZExtValue());
3141       return get(V->getContext(), Elts);
3142     }
3143     if (CI->getType()->isIntegerTy(32)) {
3144       SmallVector<uint32_t, 16> Elts(NumElts, CI->getZExtValue());
3145       return get(V->getContext(), Elts);
3146     }
3147     assert(CI->getType()->isIntegerTy(64) && "Unsupported ConstantData type");
3148     SmallVector<uint64_t, 16> Elts(NumElts, CI->getZExtValue());
3149     return get(V->getContext(), Elts);
3150   }
3151
3152   if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
3153     if (CFP->getType()->isHalfTy()) {
3154       SmallVector<uint16_t, 16> Elts(
3155           NumElts, CFP->getValueAPF().bitcastToAPInt().getLimitedValue());
3156       return getFP(V->getType(), Elts);
3157     }
3158     if (CFP->getType()->isBFloatTy()) {
3159       SmallVector<uint16_t, 16> Elts(
3160           NumElts, CFP->getValueAPF().bitcastToAPInt().getLimitedValue());
3161       return getFP(V->getType(), Elts);
3162     }
3163     if (CFP->getType()->isFloatTy()) {
3164       SmallVector<uint32_t, 16> Elts(
3165           NumElts, CFP->getValueAPF().bitcastToAPInt().getLimitedValue());
3166       return getFP(V->getType(), Elts);
3167     }
3168     if (CFP->getType()->isDoubleTy()) {
3169       SmallVector<uint64_t, 16> Elts(
3170           NumElts, CFP->getValueAPF().bitcastToAPInt().getLimitedValue());
3171       return getFP(V->getType(), Elts);
3172     }
3173   }
3174   return ConstantVector::getSplat(ElementCount::getFixed(NumElts), V);
3175 }
3176
3177
3178 uint64_t ConstantDataSequential::getElementAsInteger(unsigned Elt) const {
3179   assert(isa<IntegerType>(getElementType()) &&
3180          "Accessor can only be used when element is an integer");
3181   const char *EltPtr = getElementPointer(Elt);
3182
3183   // The data is stored in host byte order, make sure to cast back to the right
3184   // type to load with the right endianness.
3185   switch (getElementType()->getIntegerBitWidth()) {
3186   default: llvm_unreachable("Invalid bitwidth for CDS");
3187   case 8:
3188     return *reinterpret_cast<const uint8_t *>(EltPtr);
3189   case 16:
3190     return *reinterpret_cast<const uint16_t *>(EltPtr);
3191   case 32:
3192     return *reinterpret_cast<const uint32_t *>(EltPtr);
3193   case 64:
3194     return *reinterpret_cast<const uint64_t *>(EltPtr);
3195   }
3196 }
3197
3198 APInt ConstantDataSequential::getElementAsAPInt(unsigned Elt) const {
3199   assert(isa<IntegerType>(getElementType()) &&
3200          "Accessor can only be used when element is an integer");
3201   const char *EltPtr = getElementPointer(Elt);
3202
3203   // The data is stored in host byte order, make sure to cast back to the right
3204   // type to load with the right endianness.
3205   switch (getElementType()->getIntegerBitWidth()) {
3206   default: llvm_unreachable("Invalid bitwidth for CDS");
3207   case 8: {
3208     auto EltVal = *reinterpret_cast<const uint8_t *>(EltPtr);
3209     return APInt(8, EltVal);
3210   }
3211   case 16: {
3212     auto EltVal = *reinterpret_cast<const uint16_t *>(EltPtr);
3213     return APInt(16, EltVal);
3214   }
3215   case 32: {
3216     auto EltVal = *reinterpret_cast<const uint32_t *>(EltPtr);
3217     return APInt(32, EltVal);
3218   }
3219   case 64: {
3220     auto EltVal = *reinterpret_cast<const uint64_t *>(EltPtr);
3221     return APInt(64, EltVal);
3222   }
3223   }
3224 }
3225
3226 APFloat ConstantDataSequential::getElementAsAPFloat(unsigned Elt) const {
3227   const char *EltPtr = getElementPointer(Elt);
3228
3229   switch (getElementType()->getTypeID()) {
3230   default:
3231     llvm_unreachable("Accessor can only be used when element is float/double!");
3232   case Type::HalfTyID: {
3233     auto EltVal = *reinterpret_cast<const uint16_t *>(EltPtr);
3234     return APFloat(APFloat::IEEEhalf(), APInt(16, EltVal));
3235   }
3236   case Type::BFloatTyID: {
3237     auto EltVal = *reinterpret_cast<const uint16_t *>(EltPtr);
3238     return APFloat(APFloat::BFloat(), APInt(16, EltVal));
3239   }
3240   case Type::FloatTyID: {
3241     auto EltVal = *reinterpret_cast<const uint32_t *>(EltPtr);
3242     return APFloat(APFloat::IEEEsingle(), APInt(32, EltVal));
3243   }
3244   case Type::DoubleTyID: {
3245     auto EltVal = *reinterpret_cast<const uint64_t *>(EltPtr);
3246     return APFloat(APFloat::IEEEdouble(), APInt(64, EltVal));
3247   }
3248   }
3249 }
3250
3251 float ConstantDataSequential::getElementAsFloat(unsigned Elt) const {
3252   assert(getElementType()->isFloatTy() &&
3253          "Accessor can only be used when element is a 'float'");
3254   return *reinterpret_cast<const float *>(getElementPointer(Elt));
3255 }
3256
3257 double ConstantDataSequential::getElementAsDouble(unsigned Elt) const {
3258   assert(getElementType()->isDoubleTy() &&
3259          "Accessor can only be used when element is a 'float'");
3260   return *reinterpret_cast<const double *>(getElementPointer(Elt));
3261 }
3262
3263 Constant *ConstantDataSequential::getElementAsConstant(unsigned Elt) const {
3264   if (getElementType()->isHalfTy() || getElementType()->isBFloatTy() ||
3265       getElementType()->isFloatTy() || getElementType()->isDoubleTy())
3266     return ConstantFP::get(getContext(), getElementAsAPFloat(Elt));
3267
3268   return ConstantInt::get(getElementType(), getElementAsInteger(Elt));
3269 }
3270
3271 bool ConstantDataSequential::isString(unsigned CharSize) const {
3272   return isa<ArrayType>(getType()) && getElementType()->isIntegerTy(CharSize);
3273 }
3274
3275 bool ConstantDataSequential::isCString() const {
3276   if (!isString())
3277     return false;
3278
3279   StringRef Str = getAsString();
3280
3281   // The last value must be nul.
3282   if (Str.back() != 0) return false;
3283
3284   // Other elements must be non-nul.
3285   return Str.drop_back().find(0) == StringRef::npos;
3286 }
3287
3288 bool ConstantDataVector::isSplatData() const {
3289   const char *Base = getRawDataValues().data();
3290
3291   // Compare elements 1+ to the 0'th element.
3292   unsigned EltSize = getElementByteSize();
3293   for (unsigned i = 1, e = getNumElements(); i != e; ++i)
3294     if (memcmp(Base, Base+i*EltSize, EltSize))
3295       return false;
3296
3297   return true;
3298 }
3299
3300 bool ConstantDataVector::isSplat() const {
3301   if (!IsSplatSet) {
3302     IsSplatSet = true;
3303     IsSplat = isSplatData();
3304   }
3305   return IsSplat;
3306 }
3307
3308 Constant *ConstantDataVector::getSplatValue() const {
3309   // If they're all the same, return the 0th one as a representative.
3310   return isSplat() ? getElementAsConstant(0) : nullptr;
3311 }
3312
3313 //===----------------------------------------------------------------------===//
3314 //                handleOperandChange implementations
3315
3316 /// Update this constant array to change uses of
3317 /// 'From' to be uses of 'To'.  This must update the uniquing data structures
3318 /// etc.
3319 ///
3320 /// Note that we intentionally replace all uses of From with To here.  Consider
3321 /// a large array that uses 'From' 1000 times.  By handling this case all here,
3322 /// ConstantArray::handleOperandChange is only invoked once, and that
3323 /// single invocation handles all 1000 uses.  Handling them one at a time would
3324 /// work, but would be really slow because it would have to unique each updated
3325 /// array instance.
3326 ///
3327 void Constant::handleOperandChange(Value *From, Value *To) {
3328   Value *Replacement = nullptr;
3329   switch (getValueID()) {
3330   default:
3331     llvm_unreachable("Not a constant!");
3332 #define HANDLE_CONSTANT(Name)                                                  \
3333   case Value::Name##Val:                                                       \
3334     Replacement = cast<Name>(this)->handleOperandChangeImpl(From, To);         \
3335     break;
3336 #include "llvm/IR/Value.def"
3337   }
3338
3339   // If handleOperandChangeImpl returned nullptr, then it handled
3340   // replacing itself and we don't want to delete or replace anything else here.
3341   if (!Replacement)
3342     return;
3343
3344   // I do need to replace this with an existing value.
3345   assert(Replacement != this && "I didn't contain From!");
3346
3347   // Everyone using this now uses the replacement.
3348   replaceAllUsesWith(Replacement);
3349
3350   // Delete the old constant!
3351   destroyConstant();
3352 }
3353
3354 Value *ConstantArray::handleOperandChangeImpl(Value *From, Value *To) {
3355   assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
3356   Constant *ToC = cast<Constant>(To);
3357
3358   SmallVector<Constant*, 8> Values;
3359   Values.reserve(getNumOperands());  // Build replacement array.
3360
3361   // Fill values with the modified operands of the constant array.  Also,
3362   // compute whether this turns into an all-zeros array.
3363   unsigned NumUpdated = 0;
3364
3365   // Keep track of whether all the values in the array are "ToC".
3366   bool AllSame = true;
3367   Use *OperandList = getOperandList();
3368   unsigned OperandNo = 0;
3369   for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O) {
3370     Constant *Val = cast<Constant>(O->get());
3371     if (Val == From) {
3372       OperandNo = (O - OperandList);
3373       Val = ToC;
3374       ++NumUpdated;
3375     }
3376     Values.push_back(Val);
3377     AllSame &= Val == ToC;
3378   }
3379
3380   if (AllSame && ToC->isNullValue())
3381     return ConstantAggregateZero::get(getType());
3382
3383   if (AllSame && isa<UndefValue>(ToC))
3384     return UndefValue::get(getType());
3385
3386   // Check for any other type of constant-folding.
3387   if (Constant *C = getImpl(getType(), Values))
3388     return C;
3389
3390   // Update to the new value.
3391   return getContext().pImpl->ArrayConstants.replaceOperandsInPlace(
3392       Values, this, From, ToC, NumUpdated, OperandNo);
3393 }
3394
3395 Value *ConstantStruct::handleOperandChangeImpl(Value *From, Value *To) {
3396   assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
3397   Constant *ToC = cast<Constant>(To);
3398
3399   Use *OperandList = getOperandList();
3400
3401   SmallVector<Constant*, 8> Values;
3402   Values.reserve(getNumOperands());  // Build replacement struct.
3403
3404   // Fill values with the modified operands of the constant struct.  Also,
3405   // compute whether this turns into an all-zeros struct.
3406   unsigned NumUpdated = 0;
3407   bool AllSame = true;
3408   unsigned OperandNo = 0;
3409   for (Use *O = OperandList, *E = OperandList + getNumOperands(); O != E; ++O) {
3410     Constant *Val = cast<Constant>(O->get());
3411     if (Val == From) {
3412       OperandNo = (O - OperandList);
3413       Val = ToC;
3414       ++NumUpdated;
3415     }
3416     Values.push_back(Val);
3417     AllSame &= Val == ToC;
3418   }
3419
3420   if (AllSame && ToC->isNullValue())
3421     return ConstantAggregateZero::get(getType());
3422
3423   if (AllSame && isa<UndefValue>(ToC))
3424     return UndefValue::get(getType());
3425
3426   // Update to the new value.
3427   return getContext().pImpl->StructConstants.replaceOperandsInPlace(
3428       Values, this, From, ToC, NumUpdated, OperandNo);
3429 }
3430
3431 Value *ConstantVector::handleOperandChangeImpl(Value *From, Value *To) {
3432   assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
3433   Constant *ToC = cast<Constant>(To);
3434
3435   SmallVector<Constant*, 8> Values;
3436   Values.reserve(getNumOperands());  // Build replacement array...
3437   unsigned NumUpdated = 0;
3438   unsigned OperandNo = 0;
3439   for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
3440     Constant *Val = getOperand(i);
3441     if (Val == From) {
3442       OperandNo = i;
3443       ++NumUpdated;
3444       Val = ToC;
3445     }
3446     Values.push_back(Val);
3447   }
3448
3449   if (Constant *C = getImpl(Values))
3450     return C;
3451
3452   // Update to the new value.
3453   return getContext().pImpl->VectorConstants.replaceOperandsInPlace(
3454       Values, this, From, ToC, NumUpdated, OperandNo);
3455 }
3456
3457 Value *ConstantExpr::handleOperandChangeImpl(Value *From, Value *ToV) {
3458   assert(isa<Constant>(ToV) && "Cannot make Constant refer to non-constant!");
3459   Constant *To = cast<Constant>(ToV);
3460
3461   SmallVector<Constant*, 8> NewOps;
3462   unsigned NumUpdated = 0;
3463   unsigned OperandNo = 0;
3464   for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
3465     Constant *Op = getOperand(i);
3466     if (Op == From) {
3467       OperandNo = i;
3468       ++NumUpdated;
3469       Op = To;
3470     }
3471     NewOps.push_back(Op);
3472   }
3473   assert(NumUpdated && "I didn't contain From!");
3474
3475   if (Constant *C = getWithOperands(NewOps, getType(), true))
3476     return C;
3477
3478   // Update to the new value.
3479   return getContext().pImpl->ExprConstants.replaceOperandsInPlace(
3480       NewOps, this, From, To, NumUpdated, OperandNo);
3481 }
3482
3483 Instruction *ConstantExpr::getAsInstruction() const {
3484   SmallVector<Value *, 4> ValueOperands(operands());
3485   ArrayRef<Value*> Ops(ValueOperands);
3486
3487   switch (getOpcode()) {
3488   case Instruction::Trunc:
3489   case Instruction::ZExt:
3490   case Instruction::SExt:
3491   case Instruction::FPTrunc:
3492   case Instruction::FPExt:
3493   case Instruction::UIToFP:
3494   case Instruction::SIToFP:
3495   case Instruction::FPToUI:
3496   case Instruction::FPToSI:
3497   case Instruction::PtrToInt:
3498   case Instruction::IntToPtr:
3499   case Instruction::BitCast:
3500   case Instruction::AddrSpaceCast:
3501     return CastInst::Create((Instruction::CastOps)getOpcode(),
3502                             Ops[0], getType());
3503   case Instruction::Select:
3504     return SelectInst::Create(Ops[0], Ops[1], Ops[2]);
3505   case Instruction::InsertElement:
3506     return InsertElementInst::Create(Ops[0], Ops[1], Ops[2]);
3507   case Instruction::ExtractElement:
3508     return ExtractElementInst::Create(Ops[0], Ops[1]);
3509   case Instruction::InsertValue:
3510     return InsertValueInst::Create(Ops[0], Ops[1], getIndices());
3511   case Instruction::ExtractValue:
3512     return ExtractValueInst::Create(Ops[0], getIndices());
3513   case Instruction::ShuffleVector:
3514     return new ShuffleVectorInst(Ops[0], Ops[1], getShuffleMask());
3515
3516   case Instruction::GetElementPtr: {
3517     const auto *GO = cast<GEPOperator>(this);
3518     if (GO->isInBounds())
3519       return GetElementPtrInst::CreateInBounds(GO->getSourceElementType(),
3520                                                Ops[0], Ops.slice(1));
3521     return GetElementPtrInst::Create(GO->getSourceElementType(), Ops[0],
3522                                      Ops.slice(1));
3523   }
3524   case Instruction::ICmp:
3525   case Instruction::FCmp:
3526     return CmpInst::Create((Instruction::OtherOps)getOpcode(),
3527                            (CmpInst::Predicate)getPredicate(), Ops[0], Ops[1]);
3528   case Instruction::FNeg:
3529     return UnaryOperator::Create((Instruction::UnaryOps)getOpcode(), Ops[0]);
3530   default:
3531     assert(getNumOperands() == 2 && "Must be binary operator?");
3532     BinaryOperator *BO =
3533       BinaryOperator::Create((Instruction::BinaryOps)getOpcode(),
3534                              Ops[0], Ops[1]);
3535     if (isa<OverflowingBinaryOperator>(BO)) {
3536       BO->setHasNoUnsignedWrap(SubclassOptionalData &
3537                                OverflowingBinaryOperator::NoUnsignedWrap);
3538       BO->setHasNoSignedWrap(SubclassOptionalData &
3539                              OverflowingBinaryOperator::NoSignedWrap);
3540     }
3541     if (isa<PossiblyExactOperator>(BO))
3542       BO->setIsExact(SubclassOptionalData & PossiblyExactOperator::IsExact);
3543     return BO;
3544   }
3545 }