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
  35 //===----------------------------------------------------------------------===//
  36 //                              Constant Class
  37 //===----------------------------------------------------------------------===//
  38
  39 bool Constant::isNegativeZeroValue() const {
  40   // Floating point values have an explicit -0.0 value.
  41   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
  42     return CFP->isZero() && CFP->isNegative();
  43
  44   // Equivalent for a vector of -0.0's.
  45   if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
  46     if (CV->getElementType()->isFloatingPointTy() && CV->isSplat())
  47       if (CV->getElementAsAPFloat(0).isNegZero())
  48         return true;
  49
  50   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
  51     if (ConstantFP *SplatCFP = dyn_cast_or_null<ConstantFP>(CV->getSplatValue()))
  52       if (SplatCFP && SplatCFP->isZero() && SplatCFP->isNegative())
  53         return true;
  54
  55   // We've already handled true FP case; any other FP vectors can't represent -0.0.
  56   if (getType()->isFPOrFPVectorTy())
  57     return false;
  58
  59   // Otherwise, just use +0.0.
  60   return isNullValue();
  61 }
  62
  63 // Return true iff this constant is positive zero (floating point), negative
  64 // zero (floating point), or a null value.
  65 bool Constant::isZeroValue() const {
  66   // Floating point values have an explicit -0.0 value.
  67   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
  68     return CFP->isZero();
  69
  70   // Equivalent for a vector of -0.0's.
  71   if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
  72     if (CV->getElementType()->isFloatingPointTy() && CV->isSplat())
  73       if (CV->getElementAsAPFloat(0).isZero())
  74         return true;
  75
  76   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
  77     if (ConstantFP *SplatCFP = dyn_cast_or_null<ConstantFP>(CV->getSplatValue()))
  78       if (SplatCFP && SplatCFP->isZero())
  79         return true;
  80
  81   // Otherwise, just use +0.0.
  82   return isNullValue();
  83 }
  84
  85 bool Constant::isNullValue() const {
  86   // 0 is null.
  87   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
  88     return CI->isZero();
  89
  90   // +0.0 is null.
  91   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
  92     return CFP->isZero() && !CFP->isNegative();
  93
  94   // constant zero is zero for aggregates, cpnull is null for pointers, none for
  95   // tokens.
  96   return isa<ConstantAggregateZero>(this) || isa<ConstantPointerNull>(this) ||
  97          isa<ConstantTokenNone>(this);
  98 }
  99
 100 bool Constant::isAllOnesValue() const {
 101   // Check for -1 integers
 102   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
 103     return CI->isMinusOne();
 104
 105   // Check for FP which are bitcasted from -1 integers
 106   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
 107     return CFP->getValueAPF().bitcastToAPInt().isAllOnesValue();
 108
 109   // Check for constant vectors which are splats of -1 values.
 110   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
 111     if (Constant *Splat = CV->getSplatValue())
 112       return Splat->isAllOnesValue();
 113
 114   // Check for constant vectors which are splats of -1 values.
 115   if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this)) {
 116     if (CV->isSplat()) {
 117       if (CV->getElementType()->isFloatingPointTy())
 118         return CV->getElementAsAPFloat(0).bitcastToAPInt().isAllOnesValue();
 119       return CV->getElementAsAPInt(0).isAllOnesValue();
 120     }
 121   }
 122
 123   return false;
 124 }
 125
 126 bool Constant::isOneValue() const {
 127   // Check for 1 integers
 128   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
 129     return CI->isOne();
 130
 131   // Check for FP which are bitcasted from 1 integers
 132   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
 133     return CFP->getValueAPF().bitcastToAPInt().isOneValue();
 134
 135   // Check for constant vectors which are splats of 1 values.
 136   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
 137     if (Constant *Splat = CV->getSplatValue())
 138       return Splat->isOneValue();
 139
 140   // Check for constant vectors which are splats of 1 values.
 141   if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this)) {
 142     if (CV->isSplat()) {
 143       if (CV->getElementType()->isFloatingPointTy())
 144         return CV->getElementAsAPFloat(0).bitcastToAPInt().isOneValue();
 145       return CV->getElementAsAPInt(0).isOneValue();
 146     }
 147   }
 148
 149   return false;
 150 }
 151
 152 bool Constant::isMinSignedValue() const {
 153   // Check for INT_MIN integers
 154   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
 155     return CI->isMinValue(/*isSigned=*/true);
 156
 157   // Check for FP which are bitcasted from INT_MIN integers
 158   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
 159     return CFP->getValueAPF().bitcastToAPInt().isMinSignedValue();
 160
 161   // Check for constant vectors which are splats of INT_MIN values.
 162   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
 163     if (Constant *Splat = CV->getSplatValue())
 164       return Splat->isMinSignedValue();
 165
 166   // Check for constant vectors which are splats of INT_MIN values.
 167   if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this)) {
 168     if (CV->isSplat()) {
 169       if (CV->getElementType()->isFloatingPointTy())
 170         return CV->getElementAsAPFloat(0).bitcastToAPInt().isMinSignedValue();
 171       return CV->getElementAsAPInt(0).isMinSignedValue();
 172     }
 173   }
 174
 175   return false;
 176 }
 177
 178 bool Constant::isNotMinSignedValue() const {
 179   // Check for INT_MIN integers
 180   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
 181     return !CI->isMinValue(/*isSigned=*/true);
 182
 183   // Check for FP which are bitcasted from INT_MIN integers
 184   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
 185     return !CFP->getValueAPF().bitcastToAPInt().isMinSignedValue();
 186
 187   // Check that vectors don't contain INT_MIN
 188   if (this->getType()->isVectorTy()) {
 189     unsigned NumElts = this->getType()->getVectorNumElements();
 190     for (unsigned i = 0; i != NumElts; ++i) {
 191       Constant *Elt = this->getAggregateElement(i);
 192       if (!Elt || !Elt->isNotMinSignedValue())
 193         return false;
 194     }
 195     return true;
 196   }
 197
 198   // It *may* contain INT_MIN, we can't tell.
 199   return false;
 200 }
 201
 202 bool Constant::isFiniteNonZeroFP() const {
 203   if (auto *CFP = dyn_cast<ConstantFP>(this))
 204     return CFP->getValueAPF().isFiniteNonZero();
 205   if (!getType()->isVectorTy())
 206     return false;
 207   for (unsigned i = 0, e = getType()->getVectorNumElements(); i != e; ++i) {
 208     auto *CFP = dyn_cast_or_null<ConstantFP>(this->getAggregateElement(i));
 209     if (!CFP || !CFP->getValueAPF().isFiniteNonZero())
 210       return false;
 211   }
 212   return true;
 213 }
 214
 215 bool Constant::isNormalFP() const {
 216   if (auto *CFP = dyn_cast<ConstantFP>(this))
 217     return CFP->getValueAPF().isNormal();
 218   if (!getType()->isVectorTy())
 219     return false;
 220   for (unsigned i = 0, e = getType()->getVectorNumElements(); i != e; ++i) {
 221     auto *CFP = dyn_cast_or_null<ConstantFP>(this->getAggregateElement(i));
 222     if (!CFP || !CFP->getValueAPF().isNormal())
 223       return false;
 224   }
 225   return true;
 226 }
 227
 228 bool Constant::hasExactInverseFP() const {
 229   if (auto *CFP = dyn_cast<ConstantFP>(this))
 230     return CFP->getValueAPF().getExactInverse(nullptr);
 231   if (!getType()->isVectorTy())
 232     return false;
 233   for (unsigned i = 0, e = getType()->getVectorNumElements(); i != e; ++i) {
 234     auto *CFP = dyn_cast_or_null<ConstantFP>(this->getAggregateElement(i));
 235     if (!CFP || !CFP->getValueAPF().getExactInverse(nullptr))
 236       return false;
 237   }
 238   return true;
 239 }
 240
 241 bool Constant::isNaN() const {
 242   if (auto *CFP = dyn_cast<ConstantFP>(this))
 243     return CFP->isNaN();
 244   if (!getType()->isVectorTy())
 245     return false;
 246   for (unsigned i = 0, e = getType()->getVectorNumElements(); i != e; ++i) {
 247     auto *CFP = dyn_cast_or_null<ConstantFP>(this->getAggregateElement(i));
 248     if (!CFP || !CFP->isNaN())
 249       return false;
 250   }
 251   return true;
 252 }
 253
 254 bool Constant::isElementWiseEqual(Value *Y) const {
 255   // Are they fully identical?
 256   if (this == Y)
 257     return true;
 258   // They may still be identical element-wise (if they have `undef`s).
 259   auto *Cy = dyn_cast<Constant>(Y);
 260   if (!Cy)
 261     return false;
 262   return PatternMatch::match(ConstantExpr::getICmp(ICmpInst::Predicate::ICMP_EQ,
 263                                                    const_cast<Constant *>(this),
 264                                                    Cy),
 265                              PatternMatch::m_One());
 266 }
 267
 268 bool Constant::containsUndefElement() const {
 269   if (!getType()->isVectorTy())
 270     return false;
 271   for (unsigned i = 0, e = getType()->getVectorNumElements(); i != e; ++i)
 272     if (isa<UndefValue>(getAggregateElement(i)))
 273       return true;
 274
 275   return false;
 276 }
 277
 278 bool Constant::containsConstantExpression() const {
 279   if (!getType()->isVectorTy())
 280     return false;
 281   for (unsigned i = 0, e = getType()->getVectorNumElements(); i != e; ++i)
 282     if (isa<ConstantExpr>(getAggregateElement(i)))
 283       return true;
 284
 285   return false;
 286 }
 287
 288 /// Constructor to create a '0' constant of arbitrary type.
 289 Constant *Constant::getNullValue(Type *Ty) {
 290   switch (Ty->getTypeID()) {
 291   case Type::IntegerTyID:
 292     return ConstantInt::get(Ty, 0);
 293   case Type::HalfTyID:
 294     return ConstantFP::get(Ty->getContext(),
 295                            APFloat::getZero(APFloat::IEEEhalf()));
 296   case Type::FloatTyID:
 297     return ConstantFP::get(Ty->getContext(),
 298                            APFloat::getZero(APFloat::IEEEsingle()));
 299   case Type::DoubleTyID:
 300     return ConstantFP::get(Ty->getContext(),
 301                            APFloat::getZero(APFloat::IEEEdouble()));
 302   case Type::X86_FP80TyID:
 303     return ConstantFP::get(Ty->getContext(),
 304                            APFloat::getZero(APFloat::x87DoubleExtended()));
 305   case Type::FP128TyID:
 306     return ConstantFP::get(Ty->getContext(),
 307                            APFloat::getZero(APFloat::IEEEquad()));
 308   case Type::PPC_FP128TyID:
 309     return ConstantFP::get(Ty->getContext(),
 310                            APFloat(APFloat::PPCDoubleDouble(),
 311                                    APInt::getNullValue(128)));
 312   case Type::PointerTyID:
 313     return ConstantPointerNull::get(cast<PointerType>(Ty));
 314   case Type::StructTyID:
 315   case Type::ArrayTyID:
 316   case Type::VectorTyID:
 317     return ConstantAggregateZero::get(Ty);
 318   case Type::TokenTyID:
 319     return ConstantTokenNone::get(Ty->getContext());
 320   default:
 321     // Function, Label, or Opaque type?
 322     llvm_unreachable("Cannot create a null constant of that type!");
 323   }
 324 }
 325
 326 Constant *Constant::getIntegerValue(Type *Ty, const APInt &V) {
 327   Type *ScalarTy = Ty->getScalarType();
 328
 329   // Create the base integer constant.
 330   Constant *C = ConstantInt::get(Ty->getContext(), V);
 331
 332   // Convert an integer to a pointer, if necessary.
 333   if (PointerType *PTy = dyn_cast<PointerType>(ScalarTy))
 334     C = ConstantExpr::getIntToPtr(C, PTy);
 335
 336   // Broadcast a scalar to a vector, if necessary.
 337   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 338     C = ConstantVector::getSplat(VTy->getNumElements(), C);
 339
 340   return C;
 341 }
 342
 343 Constant *Constant::getAllOnesValue(Type *Ty) {
 344   if (IntegerType *ITy = dyn_cast<IntegerType>(Ty))
 345     return ConstantInt::get(Ty->getContext(),
 346                             APInt::getAllOnesValue(ITy->getBitWidth()));
 347
 348   if (Ty->isFloatingPointTy()) {
 349     APFloat FL = APFloat::getAllOnesValue(Ty->getPrimitiveSizeInBits(),
 350                                           !Ty->isPPC_FP128Ty());
 351     return ConstantFP::get(Ty->getContext(), FL);
 352   }
 353
 354   VectorType *VTy = cast<VectorType>(Ty);
 355   return ConstantVector::getSplat(VTy->getNumElements(),
 356                                   getAllOnesValue(VTy->getElementType()));
 357 }
 358
 359 Constant *Constant::getAggregateElement(unsigned Elt) const {
 360   if (const ConstantAggregate *CC = dyn_cast<ConstantAggregate>(this))
 361     return Elt < CC->getNumOperands() ? CC->getOperand(Elt) : nullptr;
 362
 363   if (const ConstantAggregateZero *CAZ = dyn_cast<ConstantAggregateZero>(this))
 364     return Elt < CAZ->getNumElements() ? CAZ->getElementValue(Elt) : nullptr;
 365
 366   if (const UndefValue *UV = dyn_cast<UndefValue>(this))
 367     return Elt < UV->getNumElements() ? UV->getElementValue(Elt) : nullptr;
 368
 369   if (const ConstantDataSequential *CDS =dyn_cast<ConstantDataSequential>(this))
 370     return Elt < CDS->getNumElements() ? CDS->getElementAsConstant(Elt)
 371                                        : nullptr;
 372   return nullptr;
 373 }
 374
 375 Constant *Constant::getAggregateElement(Constant *Elt) const {
 376   assert(isa<IntegerType>(Elt->getType()) && "Index must be an integer");
 377   if (ConstantInt *CI = dyn_cast<ConstantInt>(Elt)) {
 378     // Check if the constant fits into an uint64_t.
 379     if (CI->getValue().getActiveBits() > 64)
 380       return nullptr;
 381     return getAggregateElement(CI->getZExtValue());
 382   }
 383   return nullptr;
 384 }
 385
 386 void Constant::destroyConstant() {
 387   /// First call destroyConstantImpl on the subclass.  This gives the subclass
 388   /// a chance to remove the constant from any maps/pools it's contained in.
 389   switch (getValueID()) {
 390   default:
 391     llvm_unreachable("Not a constant!");
 392 #define HANDLE_CONSTANT(Name)                                                  \
 393   case Value::Name##Val:                                                       \
 394     cast<Name>(this)->destroyConstantImpl();                                   \
 395     break;
 396 #include "llvm/IR/Value.def"
 397   }
 398
 399   // When a Constant is destroyed, there may be lingering
 400   // references to the constant by other constants in the constant pool.  These
 401   // constants are implicitly dependent on the module that is being deleted,
 402   // but they don't know that.  Because we only find out when the CPV is
 403   // deleted, we must now notify all of our users (that should only be
 404   // Constants) that they are, in fact, invalid now and should be deleted.
 405   //
 406   while (!use_empty()) {
 407     Value *V = user_back();
 408 #ifndef NDEBUG // Only in -g mode...
 409     if (!isa<Constant>(V)) {
 410       dbgs() << "While deleting: " << *this
 411              << "\n\nUse still stuck around after Def is destroyed: " << *V
 412              << "\n\n";
 413     }
 414 #endif
 415     assert(isa<Constant>(V) && "References remain to Constant being destroyed");
 416     cast<Constant>(V)->destroyConstant();
 417
 418     // The constant should remove itself from our use list...
 419     assert((use_empty() || user_back() != V) && "Constant not removed!");
 420   }
 421
 422   // Value has no outstanding references it is safe to delete it now...
 423   delete this;
 424 }
 425
 426 static bool canTrapImpl(const Constant *C,
 427                         SmallPtrSetImpl<const ConstantExpr *> &NonTrappingOps) {
 428   assert(C->getType()->isFirstClassType() && "Cannot evaluate aggregate vals!");
 429   // The only thing that could possibly trap are constant exprs.
 430   const ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
 431   if (!CE)
 432     return false;
 433
 434   // ConstantExpr traps if any operands can trap.
 435   for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
 436     if (ConstantExpr *Op = dyn_cast<ConstantExpr>(CE->getOperand(i))) {
 437       if (NonTrappingOps.insert(Op).second && canTrapImpl(Op, NonTrappingOps))
 438         return true;
 439     }
 440   }
 441
 442   // Otherwise, only specific operations can trap.
 443   switch (CE->getOpcode()) {
 444   default:
 445     return false;
 446   case Instruction::UDiv:
 447   case Instruction::SDiv:
 448   case Instruction::URem:
 449   case Instruction::SRem:
 450     // Div and rem can trap if the RHS is not known to be non-zero.
 451     if (!isa<ConstantInt>(CE->getOperand(1)) ||CE->getOperand(1)->isNullValue())
 452       return true;
 453     return false;
 454   }
 455 }
 456
 457 bool Constant::canTrap() const {
 458   SmallPtrSet<const ConstantExpr *, 4> NonTrappingOps;
 459   return canTrapImpl(this, NonTrappingOps);
 460 }
 461
 462 /// Check if C contains a GlobalValue for which Predicate is true.
 463 static bool
 464 ConstHasGlobalValuePredicate(const Constant *C,
 465                              bool (*Predicate)(const GlobalValue *)) {
 466   SmallPtrSet<const Constant *, 8> Visited;
 467   SmallVector<const Constant *, 8> WorkList;
 468   WorkList.push_back(C);
 469   Visited.insert(C);
 470
 471   while (!WorkList.empty()) {
 472     const Constant *WorkItem = WorkList.pop_back_val();
 473     if (const auto *GV = dyn_cast<GlobalValue>(WorkItem))
 474       if (Predicate(GV))
 475         return true;
 476     for (const Value *Op : WorkItem->operands()) {
 477       const Constant *ConstOp = dyn_cast<Constant>(Op);
 478       if (!ConstOp)
 479         continue;
 480       if (Visited.insert(ConstOp).second)
 481         WorkList.push_back(ConstOp);
 482     }
 483   }
 484   return false;
 485 }
 486
 487 bool Constant::isThreadDependent() const {
 488   auto DLLImportPredicate = [](const GlobalValue *GV) {
 489     return GV->isThreadLocal();
 490   };
 491   return ConstHasGlobalValuePredicate(this, DLLImportPredicate);
 492 }
 493
 494 bool Constant::isDLLImportDependent() const {
 495   auto DLLImportPredicate = [](const GlobalValue *GV) {
 496     return GV->hasDLLImportStorageClass();
 497   };
 498   return ConstHasGlobalValuePredicate(this, DLLImportPredicate);
 499 }
 500
 501 bool Constant::isConstantUsed() const {
 502   for (const User *U : users()) {
 503     const Constant *UC = dyn_cast<Constant>(U);
 504     if (!UC || isa<GlobalValue>(UC))
 505       return true;
 506
 507     if (UC->isConstantUsed())
 508       return true;
 509   }
 510   return false;
 511 }
 512
 513 bool Constant::needsRelocation() const {
 514   if (isa<GlobalValue>(this))
 515     return true; // Global reference.
 516
 517   if (const BlockAddress *BA = dyn_cast<BlockAddress>(this))
 518     return BA->getFunction()->needsRelocation();
 519
 520   if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) {
 521     if (CE->getOpcode() == Instruction::Sub) {
 522       ConstantExpr *LHS = dyn_cast<ConstantExpr>(CE->getOperand(0));
 523       ConstantExpr *RHS = dyn_cast<ConstantExpr>(CE->getOperand(1));
 524       if (LHS && RHS && LHS->getOpcode() == Instruction::PtrToInt &&
 525           RHS->getOpcode() == Instruction::PtrToInt) {
 526         Constant *LHSOp0 = LHS->getOperand(0);
 527         Constant *RHSOp0 = RHS->getOperand(0);
 528
 529         // While raw uses of blockaddress need to be relocated, differences
 530         // between two of them don't when they are for labels in the same
 531         // function.  This is a common idiom when creating a table for the
 532         // indirect goto extension, so we handle it efficiently here.
 533         if (isa<BlockAddress>(LHSOp0) && isa<BlockAddress>(RHSOp0) &&
 534             cast<BlockAddress>(LHSOp0)->getFunction() ==
 535                 cast<BlockAddress>(RHSOp0)->getFunction())
 536           return false;
 537
 538         // Relative pointers do not need to be dynamically relocated.
 539         if (auto *LHSGV = dyn_cast<GlobalValue>(LHSOp0->stripPointerCasts()))
 540           if (auto *RHSGV = dyn_cast<GlobalValue>(RHSOp0->stripPointerCasts()))
 541             if (LHSGV->isDSOLocal() && RHSGV->isDSOLocal())
 542               return false;
 543       }
 544     }
 545   }
 546
 547   bool Result = false;
 548   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
 549     Result |= cast<Constant>(getOperand(i))->needsRelocation();
 550
 551   return Result;
 552 }
 553
 554 /// If the specified constantexpr is dead, remove it. This involves recursively
 555 /// eliminating any dead users of the constantexpr.
 556 static bool removeDeadUsersOfConstant(const Constant *C) {
 557   if (isa<GlobalValue>(C)) return false; // Cannot remove this
 558
 559   while (!C->use_empty()) {
 560     const Constant *User = dyn_cast<Constant>(C->user_back());
 561     if (!User) return false; // Non-constant usage;
 562     if (!removeDeadUsersOfConstant(User))
 563       return false; // Constant wasn't dead
 564   }
 565
 566   const_cast<Constant*>(C)->destroyConstant();
 567   return true;
 568 }
 569
 570
 571 void Constant::removeDeadConstantUsers() const {
 572   Value::const_user_iterator I = user_begin(), E = user_end();
 573   Value::const_user_iterator LastNonDeadUser = E;
 574   while (I != E) {
 575     const Constant *User = dyn_cast<Constant>(*I);
 576     if (!User) {
 577       LastNonDeadUser = I;
 578       ++I;
 579       continue;
 580     }
 581
 582     if (!removeDeadUsersOfConstant(User)) {
 583       // If the constant wasn't dead, remember that this was the last live use
 584       // and move on to the next constant.
 585       LastNonDeadUser = I;
 586       ++I;
 587       continue;
 588     }
 589
 590     // If the constant was dead, then the iterator is invalidated.
 591     if (LastNonDeadUser == E)
 592       I = user_begin();
 593     else
 594       I = std::next(LastNonDeadUser);
 595   }
 596 }
 597
 598
 599
 600 //===----------------------------------------------------------------------===//
 601 //                                ConstantInt
 602 //===----------------------------------------------------------------------===//
 603
 604 ConstantInt::ConstantInt(IntegerType *Ty, const APInt &V)
 605     : ConstantData(Ty, ConstantIntVal), Val(V) {
 606   assert(V.getBitWidth() == Ty->getBitWidth() && "Invalid constant for type");
 607 }
 608
 609 ConstantInt *ConstantInt::getTrue(LLVMContext &Context) {
 610   LLVMContextImpl *pImpl = Context.pImpl;
 611   if (!pImpl->TheTrueVal)
 612     pImpl->TheTrueVal = ConstantInt::get(Type::getInt1Ty(Context), 1);
 613   return pImpl->TheTrueVal;
 614 }
 615
 616 ConstantInt *ConstantInt::getFalse(LLVMContext &Context) {
 617   LLVMContextImpl *pImpl = Context.pImpl;
 618   if (!pImpl->TheFalseVal)
 619     pImpl->TheFalseVal = ConstantInt::get(Type::getInt1Ty(Context), 0);
 620   return pImpl->TheFalseVal;
 621 }
 622
 623 Constant *ConstantInt::getTrue(Type *Ty) {
 624   assert(Ty->isIntOrIntVectorTy(1) && "Type not i1 or vector of i1.");
 625   ConstantInt *TrueC = ConstantInt::getTrue(Ty->getContext());
 626   if (auto *VTy = dyn_cast<VectorType>(Ty))
 627     return ConstantVector::getSplat(VTy->getNumElements(), TrueC);
 628   return TrueC;
 629 }
 630
 631 Constant *ConstantInt::getFalse(Type *Ty) {
 632   assert(Ty->isIntOrIntVectorTy(1) && "Type not i1 or vector of i1.");
 633   ConstantInt *FalseC = ConstantInt::getFalse(Ty->getContext());
 634   if (auto *VTy = dyn_cast<VectorType>(Ty))
 635     return ConstantVector::getSplat(VTy->getNumElements(), FalseC);
 636   return FalseC;
 637 }
 638
 639 // Get a ConstantInt from an APInt.
 640 ConstantInt *ConstantInt::get(LLVMContext &Context, const APInt &V) {
 641   // get an existing value or the insertion position
 642   LLVMContextImpl *pImpl = Context.pImpl;
 643   std::unique_ptr<ConstantInt> &Slot = pImpl->IntConstants[V];
 644   if (!Slot) {
 645     // Get the corresponding integer type for the bit width of the value.
 646     IntegerType *ITy = IntegerType::get(Context, V.getBitWidth());
 647     Slot.reset(new ConstantInt(ITy, V));
 648   }
 649   assert(Slot->getType() == IntegerType::get(Context, V.getBitWidth()));
 650   return Slot.get();
 651 }
 652
 653 Constant *ConstantInt::get(Type *Ty, uint64_t V, bool isSigned) {
 654   Constant *C = get(cast<IntegerType>(Ty->getScalarType()), V, isSigned);
 655
 656   // For vectors, broadcast the value.
 657   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 658     return ConstantVector::getSplat(VTy->getNumElements(), C);
 659
 660   return C;
 661 }
 662
 663 ConstantInt *ConstantInt::get(IntegerType *Ty, uint64_t V, bool isSigned) {
 664   return get(Ty->getContext(), APInt(Ty->getBitWidth(), V, isSigned));
 665 }
 666
 667 ConstantInt *ConstantInt::getSigned(IntegerType *Ty, int64_t V) {
 668   return get(Ty, V, true);
 669 }
 670
 671 Constant *ConstantInt::getSigned(Type *Ty, int64_t V) {
 672   return get(Ty, V, true);
 673 }
 674
 675 Constant *ConstantInt::get(Type *Ty, const APInt& V) {
 676   ConstantInt *C = get(Ty->getContext(), V);
 677   assert(C->getType() == Ty->getScalarType() &&
 678          "ConstantInt type doesn't match the type implied by its value!");
 679
 680   // For vectors, broadcast the value.
 681   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 682     return ConstantVector::getSplat(VTy->getNumElements(), C);
 683
 684   return C;
 685 }
 686
 687 ConstantInt *ConstantInt::get(IntegerType* Ty, StringRef Str, uint8_t radix) {
 688   return get(Ty->getContext(), APInt(Ty->getBitWidth(), Str, radix));
 689 }
 690
 691 /// Remove the constant from the constant table.
 692 void ConstantInt::destroyConstantImpl() {
 693   llvm_unreachable("You can't ConstantInt->destroyConstantImpl()!");
 694 }
 695
 696 //===----------------------------------------------------------------------===//
 697 //                                ConstantFP
 698 //===----------------------------------------------------------------------===//
 699
 700 static const fltSemantics *TypeToFloatSemantics(Type *Ty) {
 701   if (Ty->isHalfTy())
 702     return &APFloat::IEEEhalf();
 703   if (Ty->isFloatTy())
 704     return &APFloat::IEEEsingle();
 705   if (Ty->isDoubleTy())
 706     return &APFloat::IEEEdouble();
 707   if (Ty->isX86_FP80Ty())
 708     return &APFloat::x87DoubleExtended();
 709   else if (Ty->isFP128Ty())
 710     return &APFloat::IEEEquad();
 711
 712   assert(Ty->isPPC_FP128Ty() && "Unknown FP format");
 713   return &APFloat::PPCDoubleDouble();
 714 }
 715
 716 Constant *ConstantFP::get(Type *Ty, double V) {
 717   LLVMContext &Context = Ty->getContext();
 718
 719   APFloat FV(V);
 720   bool ignored;
 721   FV.convert(*TypeToFloatSemantics(Ty->getScalarType()),
 722              APFloat::rmNearestTiesToEven, &ignored);
 723   Constant *C = get(Context, FV);
 724
 725   // For vectors, broadcast the value.
 726   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 727     return ConstantVector::getSplat(VTy->getNumElements(), C);
 728
 729   return C;
 730 }
 731
 732 Constant *ConstantFP::get(Type *Ty, const APFloat &V) {
 733   ConstantFP *C = get(Ty->getContext(), V);
 734   assert(C->getType() == Ty->getScalarType() &&
 735          "ConstantFP type doesn't match the type implied by its value!");
 736
 737   // For vectors, broadcast the value.
 738   if (auto *VTy = dyn_cast<VectorType>(Ty))
 739     return ConstantVector::getSplat(VTy->getNumElements(), C);
 740
 741   return C;
 742 }
 743
 744 Constant *ConstantFP::get(Type *Ty, StringRef Str) {
 745   LLVMContext &Context = Ty->getContext();
 746
 747   APFloat FV(*TypeToFloatSemantics(Ty->getScalarType()), Str);
 748   Constant *C = get(Context, FV);
 749
 750   // For vectors, broadcast the value.
 751   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 752     return ConstantVector::getSplat(VTy->getNumElements(), C);
 753
 754   return C;
 755 }
 756
 757 Constant *ConstantFP::getNaN(Type *Ty, bool Negative, uint64_t Payload) {
 758   const fltSemantics &Semantics = *TypeToFloatSemantics(Ty->getScalarType());
 759   APFloat NaN = APFloat::getNaN(Semantics, Negative, Payload);
 760   Constant *C = get(Ty->getContext(), NaN);
 761
 762   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 763     return ConstantVector::getSplat(VTy->getNumElements(), C);
 764
 765   return C;
 766 }
 767
 768 Constant *ConstantFP::getQNaN(Type *Ty, bool Negative, APInt *Payload) {
 769   const fltSemantics &Semantics = *TypeToFloatSemantics(Ty->getScalarType());
 770   APFloat NaN = APFloat::getQNaN(Semantics, Negative, Payload);
 771   Constant *C = get(Ty->getContext(), NaN);
 772
 773   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 774     return ConstantVector::getSplat(VTy->getNumElements(), C);
 775
 776   return C;
 777 }
 778
 779 Constant *ConstantFP::getSNaN(Type *Ty, bool Negative, APInt *Payload) {
 780   const fltSemantics &Semantics = *TypeToFloatSemantics(Ty->getScalarType());
 781   APFloat NaN = APFloat::getSNaN(Semantics, Negative, Payload);
 782   Constant *C = get(Ty->getContext(), NaN);
 783
 784   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 785     return ConstantVector::getSplat(VTy->getNumElements(), C);
 786
 787   return C;
 788 }
 789
 790 Constant *ConstantFP::getNegativeZero(Type *Ty) {
 791   const fltSemantics &Semantics = *TypeToFloatSemantics(Ty->getScalarType());
 792   APFloat NegZero = APFloat::getZero(Semantics, /*Negative=*/true);
 793   Constant *C = get(Ty->getContext(), NegZero);
 794
 795   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 796     return ConstantVector::getSplat(VTy->getNumElements(), C);
 797
 798   return C;
 799 }
 800
 801
 802 Constant *ConstantFP::getZeroValueForNegation(Type *Ty) {
 803   if (Ty->isFPOrFPVectorTy())
 804     return getNegativeZero(Ty);
 805
 806   return Constant::getNullValue(Ty);
 807 }
 808
 809
 810 // ConstantFP accessors.
 811 ConstantFP* ConstantFP::get(LLVMContext &Context, const APFloat& V) {
 812   LLVMContextImpl* pImpl = Context.pImpl;
 813
 814   std::unique_ptr<ConstantFP> &Slot = pImpl->FPConstants[V];
 815
 816   if (!Slot) {
 817     Type *Ty;
 818     if (&V.getSemantics() == &APFloat::IEEEhalf())
 819       Ty = Type::getHalfTy(Context);
 820     else if (&V.getSemantics() == &APFloat::IEEEsingle())
 821       Ty = Type::getFloatTy(Context);
 822     else if (&V.getSemantics() == &APFloat::IEEEdouble())
 823       Ty = Type::getDoubleTy(Context);
 824     else if (&V.getSemantics() == &APFloat::x87DoubleExtended())
 825       Ty = Type::getX86_FP80Ty(Context);
 826     else if (&V.getSemantics() == &APFloat::IEEEquad())
 827       Ty = Type::getFP128Ty(Context);
 828     else {
 829       assert(&V.getSemantics() == &APFloat::PPCDoubleDouble() &&
 830              "Unknown FP format");
 831       Ty = Type::getPPC_FP128Ty(Context);
 832     }
 833     Slot.reset(new ConstantFP(Ty, V));
 834   }
 835
 836   return Slot.get();
 837 }
 838
 839 Constant *ConstantFP::getInfinity(Type *Ty, bool Negative) {
 840   const fltSemantics &Semantics = *TypeToFloatSemantics(Ty->getScalarType());
 841   Constant *C = get(Ty->getContext(), APFloat::getInf(Semantics, Negative));
 842
 843   if (VectorType *VTy = dyn_cast<VectorType>(Ty))
 844     return ConstantVector::getSplat(VTy->getNumElements(), C);
 845
 846   return C;
 847 }
 848
 849 ConstantFP::ConstantFP(Type *Ty, const APFloat &V)
 850     : ConstantData(Ty, ConstantFPVal), Val(V) {
 851   assert(&V.getSemantics() == TypeToFloatSemantics(Ty) &&
 852          "FP type Mismatch");
 853 }
 854
 855 bool ConstantFP::isExactlyValue(const APFloat &V) const {
 856   return Val.bitwiseIsEqual(V);
 857 }
 858
 859 /// Remove the constant from the constant table.
 860 void ConstantFP::destroyConstantImpl() {
 861   llvm_unreachable("You can't ConstantFP->destroyConstantImpl()!");
 862 }
 863
 864 //===----------------------------------------------------------------------===//
 865 //                   ConstantAggregateZero Implementation
 866 //===----------------------------------------------------------------------===//
 867
 868 Constant *ConstantAggregateZero::getSequentialElement() const {
 869   return Constant::getNullValue(getType()->getSequentialElementType());
 870 }
 871
 872 Constant *ConstantAggregateZero::getStructElement(unsigned Elt) const {
 873   return Constant::getNullValue(getType()->getStructElementType(Elt));
 874 }
 875
 876 Constant *ConstantAggregateZero::getElementValue(Constant *C) const {
 877   if (isa<SequentialType>(getType()))
 878     return getSequentialElement();
 879   return getStructElement(cast<ConstantInt>(C)->getZExtValue());
 880 }
 881
 882 Constant *ConstantAggregateZero::getElementValue(unsigned Idx) const {
 883   if (isa<SequentialType>(getType()))
 884     return getSequentialElement();
 885   return getStructElement(Idx);
 886 }
 887
 888 unsigned ConstantAggregateZero::getNumElements() const {
 889   Type *Ty = getType();
 890   if (auto *AT = dyn_cast<ArrayType>(Ty))
 891     return AT->getNumElements();
 892   if (auto *VT = dyn_cast<VectorType>(Ty))
 893     return VT->getNumElements();
 894   return Ty->getStructNumElements();
 895 }
 896
 897 //===----------------------------------------------------------------------===//
 898 //                         UndefValue Implementation
 899 //===----------------------------------------------------------------------===//
 900
 901 UndefValue *UndefValue::getSequentialElement() const {
 902   return UndefValue::get(getType()->getSequentialElementType());
 903 }
 904
 905 UndefValue *UndefValue::getStructElement(unsigned Elt) const {
 906   return UndefValue::get(getType()->getStructElementType(Elt));
 907 }
 908
 909 UndefValue *UndefValue::getElementValue(Constant *C) const {
 910   if (isa<SequentialType>(getType()))
 911     return getSequentialElement();
 912   return getStructElement(cast<ConstantInt>(C)->getZExtValue());
 913 }
 914
 915 UndefValue *UndefValue::getElementValue(unsigned Idx) const {
 916   if (isa<SequentialType>(getType()))
 917     return getSequentialElement();
 918   return getStructElement(Idx);
 919 }
 920
 921 unsigned UndefValue::getNumElements() const {
 922   Type *Ty = getType();
 923   if (auto *ST = dyn_cast<SequentialType>(Ty))
 924     return ST->getNumElements();
 925   return Ty->getStructNumElements();
 926 }
 927
 928 //===----------------------------------------------------------------------===//
 929 //                            ConstantXXX Classes
 930 //===----------------------------------------------------------------------===//
 931
 932 template <typename ItTy, typename EltTy>
 933 static bool rangeOnlyContains(ItTy Start, ItTy End, EltTy Elt) {
 934   for (; Start != End; ++Start)
 935     if (*Start != Elt)
 936       return false;
 937   return true;
 938 }
 939
 940 template <typename SequentialTy, typename ElementTy>
 941 static Constant *getIntSequenceIfElementsMatch(ArrayRef<Constant *> V) {
 942   assert(!V.empty() && "Cannot get empty int sequence.");
 943
 944   SmallVector<ElementTy, 16> Elts;
 945   for (Constant *C : V)
 946     if (auto *CI = dyn_cast<ConstantInt>(C))
 947       Elts.push_back(CI->getZExtValue());
 948     else
 949       return nullptr;
 950   return SequentialTy::get(V[0]->getContext(), Elts);
 951 }
 952
 953 template <typename SequentialTy, typename ElementTy>
 954 static Constant *getFPSequenceIfElementsMatch(ArrayRef<Constant *> V) {
 955   assert(!V.empty() && "Cannot get empty FP sequence.");
 956
 957   SmallVector<ElementTy, 16> Elts;
 958   for (Constant *C : V)
 959     if (auto *CFP = dyn_cast<ConstantFP>(C))
 960       Elts.push_back(CFP->getValueAPF().bitcastToAPInt().getLimitedValue());
 961     else
 962       return nullptr;
 963   return SequentialTy::getFP(V[0]->getContext(), Elts);
 964 }
 965
 966 template <typename SequenceTy>
 967 static Constant *getSequenceIfElementsMatch(Constant *C,
 968                                             ArrayRef<Constant *> V) {
 969   // We speculatively build the elements here even if it turns out that there is
 970   // a constantexpr or something else weird, since it is so uncommon for that to
 971   // happen.
 972   if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
 973     if (CI->getType()->isIntegerTy(8))
 974       return getIntSequenceIfElementsMatch<SequenceTy, uint8_t>(V);
 975     else if (CI->getType()->isIntegerTy(16))
 976       return getIntSequenceIfElementsMatch<SequenceTy, uint16_t>(V);
 977     else if (CI->getType()->isIntegerTy(32))
 978       return getIntSequenceIfElementsMatch<SequenceTy, uint32_t>(V);
 979     else if (CI->getType()->isIntegerTy(64))
 980       return getIntSequenceIfElementsMatch<SequenceTy, uint64_t>(V);
 981   } else if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
 982     if (CFP->getType()->isHalfTy())
 983       return getFPSequenceIfElementsMatch<SequenceTy, uint16_t>(V);
 984     else if (CFP->getType()->isFloatTy())
 985       return getFPSequenceIfElementsMatch<SequenceTy, uint32_t>(V);
 986     else if (CFP->getType()->isDoubleTy())
 987       return getFPSequenceIfElementsMatch<SequenceTy, uint64_t>(V);
 988   }
 989
 990   return nullptr;
 991 }
 992
 993 ConstantAggregate::ConstantAggregate(CompositeType *T, ValueTy VT,
 994                                      ArrayRef<Constant *> V)
 995     : Constant(T, VT, OperandTraits<ConstantAggregate>::op_end(this) - V.size(),
 996                V.size()) {
 997   llvm::copy(V, op_begin());
 998
 999   // Check that types match, unless this is an opaque struct.
1000   if (auto *ST = dyn_cast<StructType>(T))
1001     if (ST->isOpaque())
1002       return;
1003   for (unsigned I = 0, E = V.size(); I != E; ++I)
1004     assert(V[I]->getType() == T->getTypeAtIndex(I) &&
1005            "Initializer for composite element doesn't match!");
1006 }
1007
1008 ConstantArray::ConstantArray(ArrayType *T, ArrayRef<Constant *> V)
1009     : ConstantAggregate(T, ConstantArrayVal, V) {
1010   assert(V.size() == T->getNumElements() &&
1011          "Invalid initializer for constant array");
1012 }
1013
1014 Constant *ConstantArray::get(ArrayType *Ty, ArrayRef<Constant*> V) {
1015   if (Constant *C = getImpl(Ty, V))
1016     return C;
1017   return Ty->getContext().pImpl->ArrayConstants.getOrCreate(Ty, V);
1018 }
1019
1020 Constant *ConstantArray::getImpl(ArrayType *Ty, ArrayRef<Constant*> V) {
1021   // Empty arrays are canonicalized to ConstantAggregateZero.
1022   if (V.empty())
1023     return ConstantAggregateZero::get(Ty);
1024
1025   for (unsigned i = 0, e = V.size(); i != e; ++i) {
1026     assert(V[i]->getType() == Ty->getElementType() &&
1027            "Wrong type in array element initializer");
1028   }
1029
1030   // If this is an all-zero array, return a ConstantAggregateZero object.  If
1031   // all undef, return an UndefValue, if "all simple", then return a
1032   // ConstantDataArray.
1033   Constant *C = V[0];
1034   if (isa<UndefValue>(C) && rangeOnlyContains(V.begin(), V.end(), C))
1035     return UndefValue::get(Ty);
1036
1037   if (C->isNullValue() && rangeOnlyContains(V.begin(), V.end(), C))
1038     return ConstantAggregateZero::get(Ty);
1039
1040   // Check to see if all of the elements are ConstantFP or ConstantInt and if
1041   // the element type is compatible with ConstantDataVector.  If so, use it.
1042   if (ConstantDataSequential::isElementTypeCompatible(C->getType()))
1043     return getSequenceIfElementsMatch<ConstantDataArray>(C, V);
1044
1045   // Otherwise, we really do want to create a ConstantArray.
1046   return nullptr;
1047 }
1048
1049 StructType *ConstantStruct::getTypeForElements(LLVMContext &Context,
1050                                                ArrayRef<Constant*> V,
1051                                                bool Packed) {
1052   unsigned VecSize = V.size();
1053   SmallVector<Type*, 16> EltTypes(VecSize);
1054   for (unsigned i = 0; i != VecSize; ++i)
1055     EltTypes[i] = V[i]->getType();
1056
1057   return StructType::get(Context, EltTypes, Packed);
1058 }
1059
1060
1061 StructType *ConstantStruct::getTypeForElements(ArrayRef<Constant*> V,
1062                                                bool Packed) {
1063   assert(!V.empty() &&
1064          "ConstantStruct::getTypeForElements cannot be called on empty list");
1065   return getTypeForElements(V[0]->getContext(), V, Packed);
1066 }
1067
1068 ConstantStruct::ConstantStruct(StructType *T, ArrayRef<Constant *> V)
1069     : ConstantAggregate(T, ConstantStructVal, V) {
1070   assert((T->isOpaque() || V.size() == T->getNumElements()) &&
1071          "Invalid initializer for constant struct");
1072 }
1073
1074 // ConstantStruct accessors.
1075 Constant *ConstantStruct::get(StructType *ST, ArrayRef<Constant*> V) {
1076   assert((ST->isOpaque() || ST->getNumElements() == V.size()) &&
1077          "Incorrect # elements specified to ConstantStruct::get");
1078
1079   // Create a ConstantAggregateZero value if all elements are zeros.
1080   bool isZero = true;
1081   bool isUndef = false;
1082
1083   if (!V.empty()) {
1084     isUndef = isa<UndefValue>(V[0]);
1085     isZero = V[0]->isNullValue();
1086     if (isUndef || isZero) {
1087       for (unsigned i = 0, e = V.size(); i != e; ++i) {
1088         if (!V[i]->isNullValue())
1089           isZero = false;
1090         if (!isa<UndefValue>(V[i]))
1091           isUndef = false;
1092       }
1093     }
1094   }
1095   if (isZero)
1096     return ConstantAggregateZero::get(ST);
1097   if (isUndef)
1098     return UndefValue::get(ST);
1099
1100   return ST->getContext().pImpl->StructConstants.getOrCreate(ST, V);
1101 }
1102
1103 ConstantVector::ConstantVector(VectorType *T, ArrayRef<Constant *> V)
1104     : ConstantAggregate(T, ConstantVectorVal, V) {
1105   assert(V.size() == T->getNumElements() &&
1106          "Invalid initializer for constant vector");
1107 }
1108
1109 // ConstantVector accessors.
1110 Constant *ConstantVector::get(ArrayRef<Constant*> V) {
1111   if (Constant *C = getImpl(V))
1112     return C;
1113   VectorType *Ty = VectorType::get(V.front()->getType(), V.size());
1114   return Ty->getContext().pImpl->VectorConstants.getOrCreate(Ty, V);
1115 }
1116
1117 Constant *ConstantVector::getImpl(ArrayRef<Constant*> V) {
1118   assert(!V.empty() && "Vectors can't be empty");
1119   VectorType *T = VectorType::get(V.front()->getType(), V.size());
1120
1121   // If this is an all-undef or all-zero vector, return a
1122   // ConstantAggregateZero or UndefValue.
1123   Constant *C = V[0];
1124   bool isZero = C->isNullValue();
1125   bool isUndef = isa<UndefValue>(C);
1126
1127   if (isZero || isUndef) {
1128     for (unsigned i = 1, e = V.size(); i != e; ++i)
1129       if (V[i] != C) {
1130         isZero = isUndef = false;
1131         break;
1132       }
1133   }
1134
1135   if (isZero)
1136     return ConstantAggregateZero::get(T);
1137   if (isUndef)
1138     return UndefValue::get(T);
1139
1140   // Check to see if all of the elements are ConstantFP or ConstantInt and if
1141   // the element type is compatible with ConstantDataVector.  If so, use it.
1142   if (ConstantDataSequential::isElementTypeCompatible(C->getType()))
1143     return getSequenceIfElementsMatch<ConstantDataVector>(C, V);
1144
1145   // Otherwise, the element type isn't compatible with ConstantDataVector, or
1146   // the operand list contains a ConstantExpr or something else strange.
1147   return nullptr;
1148 }
1149
1150 Constant *ConstantVector::getSplat(unsigned NumElts, Constant *V) {
1151   // If this splat is compatible with ConstantDataVector, use it instead of
1152   // ConstantVector.
1153   if ((isa<ConstantFP>(V) || isa<ConstantInt>(V)) &&
1154       ConstantDataSequential::isElementTypeCompatible(V->getType()))
1155     return ConstantDataVector::getSplat(NumElts, V);
1156
1157   SmallVector<Constant*, 32> Elts(NumElts, V);
1158   return get(Elts);
1159 }
1160
1161 ConstantTokenNone *ConstantTokenNone::get(LLVMContext &Context) {
1162   LLVMContextImpl *pImpl = Context.pImpl;
1163   if (!pImpl->TheNoneToken)
1164     pImpl->TheNoneToken.reset(new ConstantTokenNone(Context));
1165   return pImpl->TheNoneToken.get();
1166 }
1167
1168 /// Remove the constant from the constant table.
1169 void ConstantTokenNone::destroyConstantImpl() {
1170   llvm_unreachable("You can't ConstantTokenNone->destroyConstantImpl()!");
1171 }
1172
1173 // Utility function for determining if a ConstantExpr is a CastOp or not. This
1174 // can't be inline because we don't want to #include Instruction.h into
1175 // Constant.h
1176 bool ConstantExpr::isCast() const {
1177   return Instruction::isCast(getOpcode());
1178 }
1179
1180 bool ConstantExpr::isCompare() const {
1181   return getOpcode() == Instruction::ICmp || getOpcode() == Instruction::FCmp;
1182 }
1183
1184 bool ConstantExpr::isGEPWithNoNotionalOverIndexing() const {
1185   if (getOpcode() != Instruction::GetElementPtr) return false;
1186
1187   gep_type_iterator GEPI = gep_type_begin(this), E = gep_type_end(this);
1188   User::const_op_iterator OI = std::next(this->op_begin());
1189
1190   // The remaining indices may be compile-time known integers within the bounds
1191   // of the corresponding notional static array types.
1192   for (; GEPI != E; ++GEPI, ++OI) {
1193     if (isa<UndefValue>(*OI))
1194       continue;
1195     auto *CI = dyn_cast<ConstantInt>(*OI);
1196     if (!CI || (GEPI.isBoundedSequential() &&
1197                 (CI->getValue().getActiveBits() > 64 ||
1198                  CI->getZExtValue() >= GEPI.getSequentialNumElements())))
1199       return false;
1200   }
1201
1202   // All the indices checked out.
1203   return true;
1204 }
1205
1206 bool ConstantExpr::hasIndices() const {
1207   return getOpcode() == Instruction::ExtractValue ||
1208          getOpcode() == Instruction::InsertValue;
1209 }
1210
1211 ArrayRef<unsigned> ConstantExpr::getIndices() const {
1212   if (const ExtractValueConstantExpr *EVCE =
1213         dyn_cast<ExtractValueConstantExpr>(this))
1214     return EVCE->Indices;
1215
1216   return cast<InsertValueConstantExpr>(this)->Indices;
1217 }
1218
1219 unsigned ConstantExpr::getPredicate() const {
1220   return cast<CompareConstantExpr>(this)->predicate;
1221 }
1222
1223 Constant *
1224 ConstantExpr::getWithOperandReplaced(unsigned OpNo, Constant *Op) const {
1225   assert(Op->getType() == getOperand(OpNo)->getType() &&
1226          "Replacing operand with value of different type!");
1227   if (getOperand(OpNo) == Op)
1228     return const_cast<ConstantExpr*>(this);
1229
1230   SmallVector<Constant*, 8> NewOps;
1231   for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
1232     NewOps.push_back(i == OpNo ? Op : getOperand(i));
1233
1234   return getWithOperands(NewOps);
1235 }
1236
1237 Constant *ConstantExpr::getWithOperands(ArrayRef<Constant *> Ops, Type *Ty,
1238                                         bool OnlyIfReduced, Type *SrcTy) const {
1239   assert(Ops.size() == getNumOperands() && "Operand count mismatch!");
1240
1241   // If no operands changed return self.
1242   if (Ty == getType() && std::equal(Ops.begin(), Ops.end(), op_begin()))
1243     return const_cast<ConstantExpr*>(this);
1244
1245   Type *OnlyIfReducedTy = OnlyIfReduced ? Ty : nullptr;
1246   switch (getOpcode()) {
1247   case Instruction::Trunc:
1248   case Instruction::ZExt:
1249   case Instruction::SExt:
1250   case Instruction::FPTrunc:
1251   case Instruction::FPExt:
1252   case Instruction::UIToFP:
1253   case Instruction::SIToFP:
1254   case Instruction::FPToUI:
1255   case Instruction::FPToSI:
1256   case Instruction::PtrToInt:
1257   case Instruction::IntToPtr:
1258   case Instruction::BitCast:
1259   case Instruction::AddrSpaceCast:
1260     return ConstantExpr::getCast(getOpcode(), Ops[0], Ty, OnlyIfReduced);
1261   case Instruction::Select:
1262     return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2], OnlyIfReducedTy);
1263   case Instruction::InsertElement:
1264     return ConstantExpr::getInsertElement(Ops[0], Ops[1], Ops[2],
1265                                           OnlyIfReducedTy);
1266   case Instruction::ExtractElement:
1267     return ConstantExpr::getExtractElement(Ops[0], Ops[1], OnlyIfReducedTy);
1268   case Instruction::InsertValue:
1269     return ConstantExpr::getInsertValue(Ops[0], Ops[1], getIndices(),
1270                                         OnlyIfReducedTy);
1271   case Instruction::ExtractValue:
1272     return ConstantExpr::getExtractValue(Ops[0], getIndices(), OnlyIfReducedTy);
1273   case Instruction::ShuffleVector:
1274     return ConstantExpr::getShuffleVector(Ops[0], Ops[1], Ops[2],
1275                                           OnlyIfReducedTy);
1276   case Instruction::GetElementPtr: {
1277     auto *GEPO = cast<GEPOperator>(this);
1278     assert(SrcTy || (Ops[0]->getType() == getOperand(0)->getType()));
1279     return ConstantExpr::getGetElementPtr(
1280         SrcTy ? SrcTy : GEPO->getSourceElementType(), Ops[0], Ops.slice(1),
1281         GEPO->isInBounds(), GEPO->getInRangeIndex(), OnlyIfReducedTy);
1282   }
1283   case Instruction::ICmp:
1284   case Instruction::FCmp:
1285     return ConstantExpr::getCompare(getPredicate(), Ops[0], Ops[1],
1286                                     OnlyIfReducedTy);
1287   default:
1288     assert(getNumOperands() == 2 && "Must be binary operator?");
1289     return ConstantExpr::get(getOpcode(), Ops[0], Ops[1], SubclassOptionalData,
1290                              OnlyIfReducedTy);
1291   }
1292 }
1293
1294
1295 //===----------------------------------------------------------------------===//
1296 //                      isValueValidForType implementations
1297
1298 bool ConstantInt::isValueValidForType(Type *Ty, uint64_t Val) {
1299   unsigned NumBits = Ty->getIntegerBitWidth(); // assert okay
1300   if (Ty->isIntegerTy(1))
1301     return Val == 0 || Val == 1;
1302   return isUIntN(NumBits, Val);
1303 }
1304
1305 bool ConstantInt::isValueValidForType(Type *Ty, int64_t Val) {
1306   unsigned NumBits = Ty->getIntegerBitWidth();
1307   if (Ty->isIntegerTy(1))
1308     return Val == 0 || Val == 1 || Val == -1;
1309   return isIntN(NumBits, Val);
1310 }
1311
1312 bool ConstantFP::isValueValidForType(Type *Ty, const APFloat& Val) {
1313   // convert modifies in place, so make a copy.
1314   APFloat Val2 = APFloat(Val);
1315   bool losesInfo;
1316   switch (Ty->getTypeID()) {
1317   default:
1318     return false;         // These can't be represented as floating point!
1319
1320   // FIXME rounding mode needs to be more flexible
1321   case Type::HalfTyID: {
1322     if (&Val2.getSemantics() == &APFloat::IEEEhalf())
1323       return true;
1324     Val2.convert(APFloat::IEEEhalf(), APFloat::rmNearestTiesToEven, &losesInfo);
1325     return !losesInfo;
1326   }
1327   case Type::FloatTyID: {
1328     if (&Val2.getSemantics() == &APFloat::IEEEsingle())
1329       return true;
1330     Val2.convert(APFloat::IEEEsingle(), APFloat::rmNearestTiesToEven, &losesInfo);
1331     return !losesInfo;
1332   }
1333   case Type::DoubleTyID: {
1334     if (&Val2.getSemantics() == &APFloat::IEEEhalf() ||
1335         &Val2.getSemantics() == &APFloat::IEEEsingle() ||
1336         &Val2.getSemantics() == &APFloat::IEEEdouble())
1337       return true;
1338     Val2.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven, &losesInfo);
1339     return !losesInfo;
1340   }
1341   case Type::X86_FP80TyID:
1342     return &Val2.getSemantics() == &APFloat::IEEEhalf() ||
1343            &Val2.getSemantics() == &APFloat::IEEEsingle() ||
1344            &Val2.getSemantics() == &APFloat::IEEEdouble() ||
1345            &Val2.getSemantics() == &APFloat::x87DoubleExtended();
1346   case Type::FP128TyID:
1347     return &Val2.getSemantics() == &APFloat::IEEEhalf() ||
1348            &Val2.getSemantics() == &APFloat::IEEEsingle() ||
1349            &Val2.getSemantics() == &APFloat::IEEEdouble() ||
1350            &Val2.getSemantics() == &APFloat::IEEEquad();
1351   case Type::PPC_FP128TyID:
1352     return &Val2.getSemantics() == &APFloat::IEEEhalf() ||
1353            &Val2.getSemantics() == &APFloat::IEEEsingle() ||
1354            &Val2.getSemantics() == &APFloat::IEEEdouble() ||
1355            &Val2.getSemantics() == &APFloat::PPCDoubleDouble();
1356   }
1357 }
1358
1359
1360 //===----------------------------------------------------------------------===//
1361 //                      Factory Function Implementation
1362
1363 ConstantAggregateZero *ConstantAggregateZero::get(Type *Ty) {
1364   assert((Ty->isStructTy() || Ty->isArrayTy() || Ty->isVectorTy()) &&
1365          "Cannot create an aggregate zero of non-aggregate type!");
1366
1367   std::unique_ptr<ConstantAggregateZero> &Entry =
1368       Ty->getContext().pImpl->CAZConstants[Ty];
1369   if (!Entry)
1370     Entry.reset(new ConstantAggregateZero(Ty));
1371
1372   return Entry.get();
1373 }
1374
1375 /// Remove the constant from the constant table.
1376 void ConstantAggregateZero::destroyConstantImpl() {
1377   getContext().pImpl->CAZConstants.erase(getType());
1378 }
1379
1380 /// Remove the constant from the constant table.
1381 void ConstantArray::destroyConstantImpl() {
1382   getType()->getContext().pImpl->ArrayConstants.remove(this);
1383 }
1384
1385
1386 //---- ConstantStruct::get() implementation...
1387 //
1388
1389 /// Remove the constant from the constant table.
1390 void ConstantStruct::destroyConstantImpl() {
1391   getType()->getContext().pImpl->StructConstants.remove(this);
1392 }
1393
1394 /// Remove the constant from the constant table.
1395 void ConstantVector::destroyConstantImpl() {
1396   getType()->getContext().pImpl->VectorConstants.remove(this);
1397 }
1398
1399 Constant *Constant::getSplatValue() const {
1400   assert(this->getType()->isVectorTy() && "Only valid for vectors!");
1401   if (isa<ConstantAggregateZero>(this))
1402     return getNullValue(this->getType()->getVectorElementType());
1403   if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
1404     return CV->getSplatValue();
1405   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
1406     return CV->getSplatValue();
1407   return nullptr;
1408 }
1409
1410 Constant *ConstantVector::getSplatValue() const {
1411   // Check out first element.
1412   Constant *Elt = getOperand(0);
1413   // Then make sure all remaining elements point to the same value.
1414   for (unsigned I = 1, E = getNumOperands(); I < E; ++I)
1415     if (getOperand(I) != Elt)
1416       return nullptr;
1417   return Elt;
1418 }
1419
1420 const APInt &Constant::getUniqueInteger() const {
1421   if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
1422     return CI->getValue();
1423   assert(this->getSplatValue() && "Doesn't contain a unique integer!");
1424   const Constant *C = this->getAggregateElement(0U);
1425   assert(C && isa<ConstantInt>(C) && "Not a vector of numbers!");
1426   return cast<ConstantInt>(C)->getValue();
1427 }
1428
1429 //---- ConstantPointerNull::get() implementation.
1430 //
1431
1432 ConstantPointerNull *ConstantPointerNull::get(PointerType *Ty) {
1433   std::unique_ptr<ConstantPointerNull> &Entry =
1434       Ty->getContext().pImpl->CPNConstants[Ty];
1435   if (!Entry)
1436     Entry.reset(new ConstantPointerNull(Ty));
1437
1438   return Entry.get();
1439 }
1440
1441 /// Remove the constant from the constant table.
1442 void ConstantPointerNull::destroyConstantImpl() {
1443   getContext().pImpl->CPNConstants.erase(getType());
1444 }
1445
1446 UndefValue *UndefValue::get(Type *Ty) {
1447   std::unique_ptr<UndefValue> &Entry = Ty->getContext().pImpl->UVConstants[Ty];
1448   if (!Entry)
1449     Entry.reset(new UndefValue(Ty));
1450
1451   return Entry.get();
1452 }
1453
1454 /// Remove the constant from the constant table.
1455 void UndefValue::destroyConstantImpl() {
1456   // Free the constant and any dangling references to it.
1457   getContext().pImpl->UVConstants.erase(getType());
1458 }
1459
1460 BlockAddress *BlockAddress::get(BasicBlock *BB) {
1461   assert(BB->getParent() && "Block must have a parent");
1462   return get(BB->getParent(), BB);
1463 }
1464
1465 BlockAddress *BlockAddress::get(Function *F, BasicBlock *BB) {
1466   BlockAddress *&BA =
1467     F->getContext().pImpl->BlockAddresses[std::make_pair(F, BB)];
1468   if (!BA)
1469     BA = new BlockAddress(F, BB);
1470
1471   assert(BA->getFunction() == F && "Basic block moved between functions");
1472   return BA;
1473 }
1474
1475 BlockAddress::BlockAddress(Function *F, BasicBlock *BB)
1476 : Constant(Type::getInt8PtrTy(F->getContext()), Value::BlockAddressVal,
1477            &Op<0>(), 2) {
1478   setOperand(0, F);
1479   setOperand(1, BB);
1480   BB->AdjustBlockAddressRefCount(1);
1481 }
1482
1483 BlockAddress *BlockAddress::lookup(const BasicBlock *BB) {
1484   if (!BB->hasAddressTaken())
1485     return nullptr;
1486
1487   const Function *F = BB->getParent();
1488   assert(F && "Block must have a parent");
1489   BlockAddress *BA =
1490       F->getContext().pImpl->BlockAddresses.lookup(std::make_pair(F, BB));
1491   assert(BA && "Refcount and block address map disagree!");
1492   return BA;
1493 }
1494
1495 /// Remove the constant from the constant table.
1496 void BlockAddress::destroyConstantImpl() {
1497   getFunction()->getType()->getContext().pImpl
1498     ->BlockAddresses.erase(std::make_pair(getFunction(), getBasicBlock()));
1499   getBasicBlock()->AdjustBlockAddressRefCount(-1);
1500 }
1501
1502 Value *BlockAddress::handleOperandChangeImpl(Value *From, Value *To) {
1503   // This could be replacing either the Basic Block or the Function.  In either
1504   // case, we have to remove the map entry.
1505   Function *NewF = getFunction();
1506   BasicBlock *NewBB = getBasicBlock();
1507
1508   if (From == NewF)
1509     NewF = cast<Function>(To->stripPointerCasts());
1510   else {
1511     assert(From == NewBB && "From does not match any operand");
1512     NewBB = cast<BasicBlock>(To);
1513   }
1514
1515   // See if the 'new' entry already exists, if not, just update this in place
1516   // and return early.
1517   BlockAddress *&NewBA =
1518     getContext().pImpl->BlockAddresses[std::make_pair(NewF, NewBB)];
1519   if (NewBA)
1520     return NewBA;
1521
1522   getBasicBlock()->AdjustBlockAddressRefCount(-1);
1523
1524   // Remove the old entry, this can't cause the map to rehash (just a
1525   // tombstone will get added).
1526   getContext().pImpl->BlockAddresses.erase(std::make_pair(getFunction(),
1527                                                           getBasicBlock()));
1528   NewBA = this;
1529   setOperand(0, NewF);
1530   setOperand(1, NewBB);
1531   getBasicBlock()->AdjustBlockAddressRefCount(1);
1532
1533   // If we just want to keep the existing value, then return null.
1534   // Callers know that this means we shouldn't delete this value.
1535   return nullptr;
1536 }
1537
1538 //---- ConstantExpr::get() implementations.
1539 //
1540
1541 /// This is a utility function to handle folding of casts and lookup of the
1542 /// cast in the ExprConstants map. It is used by the various get* methods below.
1543 static Constant *getFoldedCast(Instruction::CastOps opc, Constant *C, Type *Ty,
1544                                bool OnlyIfReduced = false) {
1545   assert(Ty->isFirstClassType() && "Cannot cast to an aggregate type!");
1546   // Fold a few common cases
1547   if (Constant *FC = ConstantFoldCastInstruction(opc, C, Ty))
1548     return FC;
1549
1550   if (OnlyIfReduced)
1551     return nullptr;
1552
1553   LLVMContextImpl *pImpl = Ty->getContext().pImpl;
1554
1555   // Look up the constant in the table first to ensure uniqueness.
1556   ConstantExprKeyType Key(opc, C);
1557
1558   return pImpl->ExprConstants.getOrCreate(Ty, Key);
1559 }
1560
1561 Constant *ConstantExpr::getCast(unsigned oc, Constant *C, Type *Ty,
1562                                 bool OnlyIfReduced) {
1563   Instruction::CastOps opc = Instruction::CastOps(oc);
1564   assert(Instruction::isCast(opc) && "opcode out of range");
1565   assert(C && Ty && "Null arguments to getCast");
1566   assert(CastInst::castIsValid(opc, C, Ty) && "Invalid constantexpr cast!");
1567
1568   switch (opc) {
1569   default:
1570     llvm_unreachable("Invalid cast opcode");
1571   case Instruction::Trunc:
1572     return getTrunc(C, Ty, OnlyIfReduced);
1573   case Instruction::ZExt:
1574     return getZExt(C, Ty, OnlyIfReduced);
1575   case Instruction::SExt:
1576     return getSExt(C, Ty, OnlyIfReduced);
1577   case Instruction::FPTrunc:
1578     return getFPTrunc(C, Ty, OnlyIfReduced);
1579   case Instruction::FPExt:
1580     return getFPExtend(C, Ty, OnlyIfReduced);
1581   case Instruction::UIToFP:
1582     return getUIToFP(C, Ty, OnlyIfReduced);
1583   case Instruction::SIToFP:
1584     return getSIToFP(C, Ty, OnlyIfReduced);
1585   case Instruction::FPToUI:
1586     return getFPToUI(C, Ty, OnlyIfReduced);
1587   case Instruction::FPToSI:
1588     return getFPToSI(C, Ty, OnlyIfReduced);
1589   case Instruction::PtrToInt:
1590     return getPtrToInt(C, Ty, OnlyIfReduced);
1591   case Instruction::IntToPtr:
1592     return getIntToPtr(C, Ty, OnlyIfReduced);
1593   case Instruction::BitCast:
1594     return getBitCast(C, Ty, OnlyIfReduced);
1595   case Instruction::AddrSpaceCast:
1596     return getAddrSpaceCast(C, Ty, OnlyIfReduced);
1597   }
1598 }
1599
1600 Constant *ConstantExpr::getZExtOrBitCast(Constant *C, Type *Ty) {
1601   if (C->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
1602     return getBitCast(C, Ty);
1603   return getZExt(C, Ty);
1604 }
1605
1606 Constant *ConstantExpr::getSExtOrBitCast(Constant *C, Type *Ty) {
1607   if (C->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
1608     return getBitCast(C, Ty);
1609   return getSExt(C, Ty);
1610 }
1611
1612 Constant *ConstantExpr::getTruncOrBitCast(Constant *C, Type *Ty) {
1613   if (C->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
1614     return getBitCast(C, Ty);
1615   return getTrunc(C, Ty);
1616 }
1617
1618 Constant *ConstantExpr::getPointerCast(Constant *S, Type *Ty) {
1619   assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
1620   assert((Ty->isIntOrIntVectorTy() || Ty->isPtrOrPtrVectorTy()) &&
1621           "Invalid cast");
1622
1623   if (Ty->isIntOrIntVectorTy())
1624     return getPtrToInt(S, Ty);
1625
1626   unsigned SrcAS = S->getType()->getPointerAddressSpace();
1627   if (Ty->isPtrOrPtrVectorTy() && SrcAS != Ty->getPointerAddressSpace())
1628     return getAddrSpaceCast(S, Ty);
1629
1630   return getBitCast(S, Ty);
1631 }
1632
1633 Constant *ConstantExpr::getPointerBitCastOrAddrSpaceCast(Constant *S,
1634                                                          Type *Ty) {
1635   assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
1636   assert(Ty->isPtrOrPtrVectorTy() && "Invalid cast");
1637
1638   if (S->getType()->getPointerAddressSpace() != Ty->getPointerAddressSpace())
1639     return getAddrSpaceCast(S, Ty);
1640
1641   return getBitCast(S, Ty);
1642 }
1643
1644 Constant *ConstantExpr::getIntegerCast(Constant *C, Type *Ty, bool isSigned) {
1645   assert(C->getType()->isIntOrIntVectorTy() &&
1646          Ty->isIntOrIntVectorTy() && "Invalid cast");
1647   unsigned SrcBits = C->getType()->getScalarSizeInBits();
1648   unsigned DstBits = Ty->getScalarSizeInBits();
1649   Instruction::CastOps opcode =
1650     (SrcBits == DstBits ? Instruction::BitCast :
1651      (SrcBits > DstBits ? Instruction::Trunc :
1652       (isSigned ? Instruction::SExt : Instruction::ZExt)));
1653   return getCast(opcode, C, Ty);
1654 }
1655
1656 Constant *ConstantExpr::getFPCast(Constant *C, Type *Ty) {
1657   assert(C->getType()->isFPOrFPVectorTy() && Ty->isFPOrFPVectorTy() &&
1658          "Invalid cast");
1659   unsigned SrcBits = C->getType()->getScalarSizeInBits();
1660   unsigned DstBits = Ty->getScalarSizeInBits();
1661   if (SrcBits == DstBits)
1662     return C; // Avoid a useless cast
1663   Instruction::CastOps opcode =
1664     (SrcBits > DstBits ? Instruction::FPTrunc : Instruction::FPExt);
1665   return getCast(opcode, C, Ty);
1666 }
1667
1668 Constant *ConstantExpr::getTrunc(Constant *C, Type *Ty, bool OnlyIfReduced) {
1669 #ifndef NDEBUG
1670   bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
1671   bool toVec = Ty->getTypeID() == Type::VectorTyID;
1672 #endif
1673   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
1674   assert(C->getType()->isIntOrIntVectorTy() && "Trunc operand must be integer");
1675   assert(Ty->isIntOrIntVectorTy() && "Trunc produces only integral");
1676   assert(C->getType()->getScalarSizeInBits() > Ty->getScalarSizeInBits()&&
1677          "SrcTy must be larger than DestTy for Trunc!");
1678
1679   return getFoldedCast(Instruction::Trunc, C, Ty, OnlyIfReduced);
1680 }
1681
1682 Constant *ConstantExpr::getSExt(Constant *C, Type *Ty, bool OnlyIfReduced) {
1683 #ifndef NDEBUG
1684   bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
1685   bool toVec = Ty->getTypeID() == Type::VectorTyID;
1686 #endif
1687   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
1688   assert(C->getType()->isIntOrIntVectorTy() && "SExt operand must be integral");
1689   assert(Ty->isIntOrIntVectorTy() && "SExt produces only integer");
1690   assert(C->getType()->getScalarSizeInBits() < Ty->getScalarSizeInBits()&&
1691          "SrcTy must be smaller than DestTy for SExt!");
1692
1693   return getFoldedCast(Instruction::SExt, C, Ty, OnlyIfReduced);
1694 }
1695
1696 Constant *ConstantExpr::getZExt(Constant *C, Type *Ty, bool OnlyIfReduced) {
1697 #ifndef NDEBUG
1698   bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
1699   bool toVec = Ty->getTypeID() == Type::VectorTyID;
1700 #endif
1701   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
1702   assert(C->getType()->isIntOrIntVectorTy() && "ZEXt operand must be integral");
1703   assert(Ty->isIntOrIntVectorTy() && "ZExt produces only integer");
1704   assert(C->getType()->getScalarSizeInBits() < Ty->getScalarSizeInBits()&&
1705          "SrcTy must be smaller than DestTy for ZExt!");
1706
1707   return getFoldedCast(Instruction::ZExt, C, Ty, OnlyIfReduced);
1708 }
1709
1710 Constant *ConstantExpr::getFPTrunc(Constant *C, Type *Ty, bool OnlyIfReduced) {
1711 #ifndef NDEBUG
1712   bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
1713   bool toVec = Ty->getTypeID() == Type::VectorTyID;
1714 #endif
1715   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
1716   assert(C->getType()->isFPOrFPVectorTy() && Ty->isFPOrFPVectorTy() &&
1717          C->getType()->getScalarSizeInBits() > Ty->getScalarSizeInBits()&&
1718          "This is an illegal floating point truncation!");
1719   return getFoldedCast(Instruction::FPTrunc, C, Ty, OnlyIfReduced);
1720 }
1721
1722 Constant *ConstantExpr::getFPExtend(Constant *C, Type *Ty, bool OnlyIfReduced) {
1723 #ifndef NDEBUG
1724   bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
1725   bool toVec = Ty->getTypeID() == Type::VectorTyID;
1726 #endif
1727   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
1728   assert(C->getType()->isFPOrFPVectorTy() && Ty->isFPOrFPVectorTy() &&
1729          C->getType()->getScalarSizeInBits() < Ty->getScalarSizeInBits()&&
1730          "This is an illegal floating point extension!");
1731   return getFoldedCast(Instruction::FPExt, C, Ty, OnlyIfReduced);
1732 }
1733
1734 Constant *ConstantExpr::getUIToFP(Constant *C, Type *Ty, bool OnlyIfReduced) {
1735 #ifndef NDEBUG
1736   bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
1737   bool toVec = Ty->getTypeID() == Type::VectorTyID;
1738 #endif
1739   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
1740   assert(C->getType()->isIntOrIntVectorTy() && Ty->isFPOrFPVectorTy() &&
1741          "This is an illegal uint to floating point cast!");
1742   return getFoldedCast(Instruction::UIToFP, C, Ty, OnlyIfReduced);
1743 }
1744
1745 Constant *ConstantExpr::getSIToFP(Constant *C, Type *Ty, bool OnlyIfReduced) {
1746 #ifndef NDEBUG
1747   bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
1748   bool toVec = Ty->getTypeID() == Type::VectorTyID;
1749 #endif
1750   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
1751   assert(C->getType()->isIntOrIntVectorTy() && Ty->isFPOrFPVectorTy() &&
1752          "This is an illegal sint to floating point cast!");
1753   return getFoldedCast(Instruction::SIToFP, C, Ty, OnlyIfReduced);
1754 }
1755
1756 Constant *ConstantExpr::getFPToUI(Constant *C, Type *Ty, bool OnlyIfReduced) {
1757 #ifndef NDEBUG
1758   bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
1759   bool toVec = Ty->getTypeID() == Type::VectorTyID;
1760 #endif
1761   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
1762   assert(C->getType()->isFPOrFPVectorTy() && Ty->isIntOrIntVectorTy() &&
1763          "This is an illegal floating point to uint cast!");
1764   return getFoldedCast(Instruction::FPToUI, C, Ty, OnlyIfReduced);
1765 }
1766
1767 Constant *ConstantExpr::getFPToSI(Constant *C, Type *Ty, bool OnlyIfReduced) {
1768 #ifndef NDEBUG
1769   bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
1770   bool toVec = Ty->getTypeID() == Type::VectorTyID;
1771 #endif
1772   assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
1773   assert(C->getType()->isFPOrFPVectorTy() && Ty->isIntOrIntVectorTy() &&
1774          "This is an illegal floating point to sint cast!");
1775   return getFoldedCast(Instruction::FPToSI, C, Ty, OnlyIfReduced);
1776 }
1777
1778 Constant *ConstantExpr::getPtrToInt(Constant *C, Type *DstTy,
1779                                     bool OnlyIfReduced) {
1780   assert(C->getType()->isPtrOrPtrVectorTy() &&
1781          "PtrToInt source must be pointer or pointer vector");
1782   assert(DstTy->isIntOrIntVectorTy() &&
1783          "PtrToInt destination must be integer or integer vector");
1784   assert(isa<VectorType>(C->getType()) == isa<VectorType>(DstTy));
1785   if (isa<VectorType>(C->getType()))
1786     assert(C->getType()->getVectorNumElements()==DstTy->getVectorNumElements()&&
1787            "Invalid cast between a different number of vector elements");
1788   return getFoldedCast(Instruction::PtrToInt, C, DstTy, OnlyIfReduced);
1789 }
1790
1791 Constant *ConstantExpr::getIntToPtr(Constant *C, Type *DstTy,
1792                                     bool OnlyIfReduced) {
1793   assert(C->getType()->isIntOrIntVectorTy() &&
1794          "IntToPtr source must be integer or integer vector");
1795   assert(DstTy->isPtrOrPtrVectorTy() &&
1796          "IntToPtr destination must be a pointer or pointer vector");
1797   assert(isa<VectorType>(C->getType()) == isa<VectorType>(DstTy));
1798   if (isa<VectorType>(C->getType()))
1799     assert(C->getType()->getVectorNumElements()==DstTy->getVectorNumElements()&&
1800            "Invalid cast between a different number of vector elements");
1801   return getFoldedCast(Instruction::IntToPtr, C, DstTy, OnlyIfReduced);
1802 }
1803
1804 Constant *ConstantExpr::getBitCast(Constant *C, Type *DstTy,
1805                                    bool OnlyIfReduced) {
1806   assert(CastInst::castIsValid(Instruction::BitCast, C, DstTy) &&
1807          "Invalid constantexpr bitcast!");
1808
1809   // It is common to ask for a bitcast of a value to its own type, handle this
1810   // speedily.
1811   if (C->getType() == DstTy) return C;
1812
1813   return getFoldedCast(Instruction::BitCast, C, DstTy, OnlyIfReduced);
1814 }
1815
1816 Constant *ConstantExpr::getAddrSpaceCast(Constant *C, Type *DstTy,
1817                                          bool OnlyIfReduced) {
1818   assert(CastInst::castIsValid(Instruction::AddrSpaceCast, C, DstTy) &&
1819          "Invalid constantexpr addrspacecast!");
1820
1821   // Canonicalize addrspacecasts between different pointer types by first
1822   // bitcasting the pointer type and then converting the address space.
1823   PointerType *SrcScalarTy = cast<PointerType>(C->getType()->getScalarType());
1824   PointerType *DstScalarTy = cast<PointerType>(DstTy->getScalarType());
1825   Type *DstElemTy = DstScalarTy->getElementType();
1826   if (SrcScalarTy->getElementType() != DstElemTy) {
1827     Type *MidTy = PointerType::get(DstElemTy, SrcScalarTy->getAddressSpace());
1828     if (VectorType *VT = dyn_cast<VectorType>(DstTy)) {
1829       // Handle vectors of pointers.
1830       MidTy = VectorType::get(MidTy, VT->getNumElements());
1831     }
1832     C = getBitCast(C, MidTy);
1833   }
1834   return getFoldedCast(Instruction::AddrSpaceCast, C, DstTy, OnlyIfReduced);
1835 }
1836
1837 Constant *ConstantExpr::get(unsigned Opcode, Constant *C, unsigned Flags,
1838                             Type *OnlyIfReducedTy) {
1839   // Check the operands for consistency first.
1840   assert(Instruction::isUnaryOp(Opcode) &&
1841          "Invalid opcode in unary constant expression");
1842
1843 #ifndef NDEBUG
1844   switch (Opcode) {
1845   case Instruction::FNeg:
1846     assert(C->getType()->isFPOrFPVectorTy() &&
1847            "Tried to create a floating-point operation on a "
1848            "non-floating-point type!");
1849     break;
1850   default:
1851     break;
1852   }
1853 #endif
1854
1855   if (Constant *FC = ConstantFoldUnaryInstruction(Opcode, C))
1856     return FC;
1857
1858   if (OnlyIfReducedTy == C->getType())
1859     return nullptr;
1860
1861   Constant *ArgVec[] = { C };
1862   ConstantExprKeyType Key(Opcode, ArgVec, 0, Flags);
1863
1864   LLVMContextImpl *pImpl = C->getContext().pImpl;
1865   return pImpl->ExprConstants.getOrCreate(C->getType(), Key);
1866 }
1867
1868 Constant *ConstantExpr::get(unsigned Opcode, Constant *C1, Constant *C2,
1869                             unsigned Flags, Type *OnlyIfReducedTy) {
1870   // Check the operands for consistency first.
1871   assert(Instruction::isBinaryOp(Opcode) &&
1872          "Invalid opcode in binary constant expression");
1873   assert(C1->getType() == C2->getType() &&
1874          "Operand types in binary constant expression should match");
1875
1876 #ifndef NDEBUG
1877   switch (Opcode) {
1878   case Instruction::Add:
1879   case Instruction::Sub:
1880   case Instruction::Mul:
1881   case Instruction::UDiv:
1882   case Instruction::SDiv:
1883   case Instruction::URem:
1884   case Instruction::SRem:
1885     assert(C1->getType()->isIntOrIntVectorTy() &&
1886            "Tried to create an integer operation on a non-integer type!");
1887     break;
1888   case Instruction::FAdd:
1889   case Instruction::FSub:
1890   case Instruction::FMul:
1891   case Instruction::FDiv:
1892   case Instruction::FRem:
1893     assert(C1->getType()->isFPOrFPVectorTy() &&
1894            "Tried to create a floating-point operation on a "
1895            "non-floating-point type!");
1896     break;
1897   case Instruction::And:
1898   case Instruction::Or:
1899   case Instruction::Xor:
1900     assert(C1->getType()->isIntOrIntVectorTy() &&
1901            "Tried to create a logical operation on a non-integral type!");
1902     break;
1903   case Instruction::Shl:
1904   case Instruction::LShr:
1905   case Instruction::AShr:
1906     assert(C1->getType()->isIntOrIntVectorTy() &&
1907            "Tried to create a shift operation on a non-integer type!");
1908     break;
1909   default:
1910     break;
1911   }
1912 #endif
1913
1914   if (Constant *FC = ConstantFoldBinaryInstruction(Opcode, C1, C2))
1915     return FC;
1916
1917   if (OnlyIfReducedTy == C1->getType())
1918     return nullptr;
1919
1920   Constant *ArgVec[] = { C1, C2 };
1921   ConstantExprKeyType Key(Opcode, ArgVec, 0, Flags);
1922
1923   LLVMContextImpl *pImpl = C1->getContext().pImpl;
1924   return pImpl->ExprConstants.getOrCreate(C1->getType(), Key);
1925 }
1926
1927 Constant *ConstantExpr::getSizeOf(Type* Ty) {
1928   // sizeof is implemented as: (i64) gep (Ty*)null, 1
1929   // Note that a non-inbounds gep is used, as null isn't within any object.
1930   Constant *GEPIdx = ConstantInt::get(Type::getInt32Ty(Ty->getContext()), 1);
1931   Constant *GEP = getGetElementPtr(
1932       Ty, Constant::getNullValue(PointerType::getUnqual(Ty)), GEPIdx);
1933   return getPtrToInt(GEP,
1934                      Type::getInt64Ty(Ty->getContext()));
1935 }
1936
1937 Constant *ConstantExpr::getAlignOf(Type* Ty) {
1938   // alignof is implemented as: (i64) gep ({i1,Ty}*)null, 0, 1
1939   // Note that a non-inbounds gep is used, as null isn't within any object.
1940   Type *AligningTy = StructType::get(Type::getInt1Ty(Ty->getContext()), Ty);
1941   Constant *NullPtr = Constant::getNullValue(AligningTy->getPointerTo(0));
1942   Constant *Zero = ConstantInt::get(Type::getInt64Ty(Ty->getContext()), 0);
1943   Constant *One = ConstantInt::get(Type::getInt32Ty(Ty->getContext()), 1);
1944   Constant *Indices[2] = { Zero, One };
1945   Constant *GEP = getGetElementPtr(AligningTy, NullPtr, Indices);
1946   return getPtrToInt(GEP,
1947                      Type::getInt64Ty(Ty->getContext()));
1948 }
1949
1950 Constant *ConstantExpr::getOffsetOf(StructType* STy, unsigned FieldNo) {
1951   return getOffsetOf(STy, ConstantInt::get(Type::getInt32Ty(STy->getContext()),
1952                                            FieldNo));
1953 }
1954
1955 Constant *ConstantExpr::getOffsetOf(Type* Ty, Constant *FieldNo) {
1956   // offsetof is implemented as: (i64) gep (Ty*)null, 0, FieldNo
1957   // Note that a non-inbounds gep is used, as null isn't within any object.
1958   Constant *GEPIdx[] = {
1959     ConstantInt::get(Type::getInt64Ty(Ty->getContext()), 0),
1960     FieldNo
1961   };
1962   Constant *GEP = getGetElementPtr(
1963       Ty, Constant::getNullValue(PointerType::getUnqual(Ty)), GEPIdx);
1964   return getPtrToInt(GEP,
1965                      Type::getInt64Ty(Ty->getContext()));
1966 }
1967
1968 Constant *ConstantExpr::getCompare(unsigned short Predicate, Constant *C1,
1969                                    Constant *C2, bool OnlyIfReduced) {
1970   assert(C1->getType() == C2->getType() && "Op types should be identical!");
1971
1972   switch (Predicate) {
1973   default: llvm_unreachable("Invalid CmpInst predicate");
1974   case CmpInst::FCMP_FALSE: case CmpInst::FCMP_OEQ: case CmpInst::FCMP_OGT:
1975   case CmpInst::FCMP_OGE:   case CmpInst::FCMP_OLT: case CmpInst::FCMP_OLE:
1976   case CmpInst::FCMP_ONE:   case CmpInst::FCMP_ORD: case CmpInst::FCMP_UNO:
1977   case CmpInst::FCMP_UEQ:   case CmpInst::FCMP_UGT: case CmpInst::FCMP_UGE:
1978   case CmpInst::FCMP_ULT:   case CmpInst::FCMP_ULE: case CmpInst::FCMP_UNE:
1979   case CmpInst::FCMP_TRUE:
1980     return getFCmp(Predicate, C1, C2, OnlyIfReduced);
1981
1982   case CmpInst::ICMP_EQ:  case CmpInst::ICMP_NE:  case CmpInst::ICMP_UGT:
1983   case CmpInst::ICMP_UGE: case CmpInst::ICMP_ULT: case CmpInst::ICMP_ULE:
1984   case CmpInst::ICMP_SGT: case CmpInst::ICMP_SGE: case CmpInst::ICMP_SLT:
1985   case CmpInst::ICMP_SLE:
1986     return getICmp(Predicate, C1, C2, OnlyIfReduced);
1987   }
1988 }
1989
1990 Constant *ConstantExpr::getSelect(Constant *C, Constant *V1, Constant *V2,
1991                                   Type *OnlyIfReducedTy) {
1992   assert(!SelectInst::areInvalidOperands(C, V1, V2)&&"Invalid select operands");
1993
1994   if (Constant *SC = ConstantFoldSelectInstruction(C, V1, V2))
1995     return SC;        // Fold common cases
1996
1997   if (OnlyIfReducedTy == V1->getType())
1998     return nullptr;
1999
2000   Constant *ArgVec[] = { C, V1, V2 };
2001   ConstantExprKeyType Key(Instruction::Select, ArgVec);
2002
2003   LLVMContextImpl *pImpl = C->getContext().pImpl;
2004   return pImpl->ExprConstants.getOrCreate(V1->getType(), Key);
2005 }
2006
2007 Constant *ConstantExpr::getGetElementPtr(Type *Ty, Constant *C,
2008                                          ArrayRef<Value *> Idxs, bool InBounds,
2009                                          Optional<unsigned> InRangeIndex,
2010                                          Type *OnlyIfReducedTy) {
2011   if (!Ty)
2012     Ty = cast<PointerType>(C->getType()->getScalarType())->getElementType();
2013   else
2014     assert(Ty ==
2015            cast<PointerType>(C->getType()->getScalarType())->getElementType());
2016
2017   if (Constant *FC =
2018           ConstantFoldGetElementPtr(Ty, C, InBounds, InRangeIndex, Idxs))
2019     return FC;          // Fold a few common cases.
2020
2021   // Get the result type of the getelementptr!
2022   Type *DestTy = GetElementPtrInst::getIndexedType(Ty, Idxs);
2023   assert(DestTy && "GEP indices invalid!");
2024   unsigned AS = C->getType()->getPointerAddressSpace();
2025   Type *ReqTy = DestTy->getPointerTo(AS);
2026
2027   unsigned NumVecElts = 0;
2028   if (C->getType()->isVectorTy())
2029     NumVecElts = C->getType()->getVectorNumElements();
2030   else for (auto Idx : Idxs)
2031     if (Idx->getType()->isVectorTy())
2032       NumVecElts = Idx->getType()->getVectorNumElements();
2033
2034   if (NumVecElts)
2035     ReqTy = VectorType::get(ReqTy, NumVecElts);
2036
2037   if (OnlyIfReducedTy == ReqTy)
2038     return nullptr;
2039
2040   // Look up the constant in the table first to ensure uniqueness
2041   std::vector<Constant*> ArgVec;
2042   ArgVec.reserve(1 + Idxs.size());
2043   ArgVec.push_back(C);
2044   for (unsigned i = 0, e = Idxs.size(); i != e; ++i) {
2045     assert((!Idxs[i]->getType()->isVectorTy() ||
2046             Idxs[i]->getType()->getVectorNumElements() == NumVecElts) &&
2047            "getelementptr index type missmatch");
2048
2049     Constant *Idx = cast<Constant>(Idxs[i]);
2050     if (NumVecElts && !Idxs[i]->getType()->isVectorTy())
2051       Idx = ConstantVector::getSplat(NumVecElts, Idx);
2052     ArgVec.push_back(Idx);
2053   }
2054
2055   unsigned SubClassOptionalData = InBounds ? GEPOperator::IsInBounds : 0;
2056   if (InRangeIndex && *InRangeIndex < 63)
2057     SubClassOptionalData |= (*InRangeIndex + 1) << 1;
2058   const ConstantExprKeyType Key(Instruction::GetElementPtr, ArgVec, 0,
2059                                 SubClassOptionalData, None, Ty);
2060
2061   LLVMContextImpl *pImpl = C->getContext().pImpl;
2062   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
2063 }
2064
2065 Constant *ConstantExpr::getICmp(unsigned short pred, Constant *LHS,
2066                                 Constant *RHS, bool OnlyIfReduced) {
2067   assert(LHS->getType() == RHS->getType());
2068   assert(CmpInst::isIntPredicate((CmpInst::Predicate)pred) &&
2069          "Invalid ICmp Predicate");
2070
2071   if (Constant *FC = ConstantFoldCompareInstruction(pred, LHS, RHS))
2072     return FC;          // Fold a few common cases...
2073
2074   if (OnlyIfReduced)
2075     return nullptr;
2076
2077   // Look up the constant in the table first to ensure uniqueness
2078   Constant *ArgVec[] = { LHS, RHS };
2079   // Get the key type with both the opcode and predicate
2080   const ConstantExprKeyType Key(Instruction::ICmp, ArgVec, pred);
2081
2082   Type *ResultTy = Type::getInt1Ty(LHS->getContext());
2083   if (VectorType *VT = dyn_cast<VectorType>(LHS->getType()))
2084     ResultTy = VectorType::get(ResultTy, VT->getNumElements());
2085
2086   LLVMContextImpl *pImpl = LHS->getType()->getContext().pImpl;
2087   return pImpl->ExprConstants.getOrCreate(ResultTy, Key);
2088 }
2089
2090 Constant *ConstantExpr::getFCmp(unsigned short pred, Constant *LHS,
2091                                 Constant *RHS, bool OnlyIfReduced) {
2092   assert(LHS->getType() == RHS->getType());
2093   assert(CmpInst::isFPPredicate((CmpInst::Predicate)pred) &&
2094          "Invalid FCmp Predicate");
2095
2096   if (Constant *FC = ConstantFoldCompareInstruction(pred, LHS, RHS))
2097     return FC;          // Fold a few common cases...
2098
2099   if (OnlyIfReduced)
2100     return nullptr;
2101
2102   // Look up the constant in the table first to ensure uniqueness
2103   Constant *ArgVec[] = { LHS, RHS };
2104   // Get the key type with both the opcode and predicate
2105   const ConstantExprKeyType Key(Instruction::FCmp, ArgVec, pred);
2106
2107   Type *ResultTy = Type::getInt1Ty(LHS->getContext());
2108   if (VectorType *VT = dyn_cast<VectorType>(LHS->getType()))
2109     ResultTy = VectorType::get(ResultTy, VT->getNumElements());
2110
2111   LLVMContextImpl *pImpl = LHS->getType()->getContext().pImpl;
2112   return pImpl->ExprConstants.getOrCreate(ResultTy, Key);
2113 }
2114
2115 Constant *ConstantExpr::getExtractElement(Constant *Val, Constant *Idx,
2116                                           Type *OnlyIfReducedTy) {
2117   assert(Val->getType()->isVectorTy() &&
2118          "Tried to create extractelement operation on non-vector type!");
2119   assert(Idx->getType()->isIntegerTy() &&
2120          "Extractelement index must be an integer type!");
2121
2122   if (Constant *FC = ConstantFoldExtractElementInstruction(Val, Idx))
2123     return FC;          // Fold a few common cases.
2124
2125   Type *ReqTy = Val->getType()->getVectorElementType();
2126   if (OnlyIfReducedTy == ReqTy)
2127     return nullptr;
2128
2129   // Look up the constant in the table first to ensure uniqueness
2130   Constant *ArgVec[] = { Val, Idx };
2131   const ConstantExprKeyType Key(Instruction::ExtractElement, ArgVec);
2132
2133   LLVMContextImpl *pImpl = Val->getContext().pImpl;
2134   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
2135 }
2136
2137 Constant *ConstantExpr::getInsertElement(Constant *Val, Constant *Elt,
2138                                          Constant *Idx, Type *OnlyIfReducedTy) {
2139   assert(Val->getType()->isVectorTy() &&
2140          "Tried to create insertelement operation on non-vector type!");
2141   assert(Elt->getType() == Val->getType()->getVectorElementType() &&
2142          "Insertelement types must match!");
2143   assert(Idx->getType()->isIntegerTy() &&
2144          "Insertelement index must be i32 type!");
2145
2146   if (Constant *FC = ConstantFoldInsertElementInstruction(Val, Elt, Idx))
2147     return FC;          // Fold a few common cases.
2148
2149   if (OnlyIfReducedTy == Val->getType())
2150     return nullptr;
2151
2152   // Look up the constant in the table first to ensure uniqueness
2153   Constant *ArgVec[] = { Val, Elt, Idx };
2154   const ConstantExprKeyType Key(Instruction::InsertElement, ArgVec);
2155
2156   LLVMContextImpl *pImpl = Val->getContext().pImpl;
2157   return pImpl->ExprConstants.getOrCreate(Val->getType(), Key);
2158 }
2159
2160 Constant *ConstantExpr::getShuffleVector(Constant *V1, Constant *V2,
2161                                          Constant *Mask, Type *OnlyIfReducedTy) {
2162   assert(ShuffleVectorInst::isValidOperands(V1, V2, Mask) &&
2163          "Invalid shuffle vector constant expr operands!");
2164
2165   if (Constant *FC = ConstantFoldShuffleVectorInstruction(V1, V2, Mask))
2166     return FC;          // Fold a few common cases.
2167
2168   unsigned NElts = Mask->getType()->getVectorNumElements();
2169   Type *EltTy = V1->getType()->getVectorElementType();
2170   Type *ShufTy = VectorType::get(EltTy, NElts);
2171
2172   if (OnlyIfReducedTy == ShufTy)
2173     return nullptr;
2174
2175   // Look up the constant in the table first to ensure uniqueness
2176   Constant *ArgVec[] = { V1, V2, Mask };
2177   const ConstantExprKeyType Key(Instruction::ShuffleVector, ArgVec);
2178
2179   LLVMContextImpl *pImpl = ShufTy->getContext().pImpl;
2180   return pImpl->ExprConstants.getOrCreate(ShufTy, Key);
2181 }
2182
2183 Constant *ConstantExpr::getInsertValue(Constant *Agg, Constant *Val,
2184                                        ArrayRef<unsigned> Idxs,
2185                                        Type *OnlyIfReducedTy) {
2186   assert(Agg->getType()->isFirstClassType() &&
2187          "Non-first-class type for constant insertvalue expression");
2188
2189   assert(ExtractValueInst::getIndexedType(Agg->getType(),
2190                                           Idxs) == Val->getType() &&
2191          "insertvalue indices invalid!");
2192   Type *ReqTy = Val->getType();
2193
2194   if (Constant *FC = ConstantFoldInsertValueInstruction(Agg, Val, Idxs))
2195     return FC;
2196
2197   if (OnlyIfReducedTy == ReqTy)
2198     return nullptr;
2199
2200   Constant *ArgVec[] = { Agg, Val };
2201   const ConstantExprKeyType Key(Instruction::InsertValue, ArgVec, 0, 0, Idxs);
2202
2203   LLVMContextImpl *pImpl = Agg->getContext().pImpl;
2204   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
2205 }
2206
2207 Constant *ConstantExpr::getExtractValue(Constant *Agg, ArrayRef<unsigned> Idxs,
2208                                         Type *OnlyIfReducedTy) {
2209   assert(Agg->getType()->isFirstClassType() &&
2210          "Tried to create extractelement operation on non-first-class type!");
2211
2212   Type *ReqTy = ExtractValueInst::getIndexedType(Agg->getType(), Idxs);
2213   (void)ReqTy;
2214   assert(ReqTy && "extractvalue indices invalid!");
2215
2216   assert(Agg->getType()->isFirstClassType() &&
2217          "Non-first-class type for constant extractvalue expression");
2218   if (Constant *FC = ConstantFoldExtractValueInstruction(Agg, Idxs))
2219     return FC;
2220
2221   if (OnlyIfReducedTy == ReqTy)
2222     return nullptr;
2223
2224   Constant *ArgVec[] = { Agg };
2225   const ConstantExprKeyType Key(Instruction::ExtractValue, ArgVec, 0, 0, Idxs);
2226
2227   LLVMContextImpl *pImpl = Agg->getContext().pImpl;
2228   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
2229 }
2230
2231 Constant *ConstantExpr::getNeg(Constant *C, bool HasNUW, bool HasNSW) {
2232   assert(C->getType()->isIntOrIntVectorTy() &&
2233          "Cannot NEG a nonintegral value!");
2234   return getSub(ConstantFP::getZeroValueForNegation(C->getType()),
2235                 C, HasNUW, HasNSW);
2236 }
2237
2238 Constant *ConstantExpr::getFNeg(Constant *C) {
2239   assert(C->getType()->isFPOrFPVectorTy() &&
2240          "Cannot FNEG a non-floating-point value!");
2241   return get(Instruction::FNeg, C);
2242 }
2243
2244 Constant *ConstantExpr::getNot(Constant *C) {
2245   assert(C->getType()->isIntOrIntVectorTy() &&
2246          "Cannot NOT a nonintegral value!");
2247   return get(Instruction::Xor, C, Constant::getAllOnesValue(C->getType()));
2248 }
2249
2250 Constant *ConstantExpr::getAdd(Constant *C1, Constant *C2,
2251                                bool HasNUW, bool HasNSW) {
2252   unsigned Flags = (HasNUW ? OverflowingBinaryOperator::NoUnsignedWrap : 0) |
2253                    (HasNSW ? OverflowingBinaryOperator::NoSignedWrap   : 0);
2254   return get(Instruction::Add, C1, C2, Flags);
2255 }
2256
2257 Constant *ConstantExpr::getFAdd(Constant *C1, Constant *C2) {
2258   return get(Instruction::FAdd, C1, C2);
2259 }
2260
2261 Constant *ConstantExpr::getSub(Constant *C1, Constant *C2,
2262                                bool HasNUW, bool HasNSW) {
2263   unsigned Flags = (HasNUW ? OverflowingBinaryOperator::NoUnsignedWrap : 0) |
2264                    (HasNSW ? OverflowingBinaryOperator::NoSignedWrap   : 0);
2265   return get(Instruction::Sub, C1, C2, Flags);
2266 }
2267
2268 Constant *ConstantExpr::getFSub(Constant *C1, Constant *C2) {
2269   return get(Instruction::FSub, C1, C2);
2270 }
2271
2272 Constant *ConstantExpr::getMul(Constant *C1, Constant *C2,
2273                                bool HasNUW, bool HasNSW) {
2274   unsigned Flags = (HasNUW ? OverflowingBinaryOperator::NoUnsignedWrap : 0) |
2275                    (HasNSW ? OverflowingBinaryOperator::NoSignedWrap   : 0);
2276   return get(Instruction::Mul, C1, C2, Flags);
2277 }
2278
2279 Constant *ConstantExpr::getFMul(Constant *C1, Constant *C2) {
2280   return get(Instruction::FMul, C1, C2);
2281 }
2282
2283 Constant *ConstantExpr::getUDiv(Constant *C1, Constant *C2, bool isExact) {
2284   return get(Instruction::UDiv, C1, C2,
2285              isExact ? PossiblyExactOperator::IsExact : 0);
2286 }
2287
2288 Constant *ConstantExpr::getSDiv(Constant *C1, Constant *C2, bool isExact) {
2289   return get(Instruction::SDiv, C1, C2,
2290              isExact ? PossiblyExactOperator::IsExact : 0);
2291 }
2292
2293 Constant *ConstantExpr::getFDiv(Constant *C1, Constant *C2) {
2294   return get(Instruction::FDiv, C1, C2);
2295 }
2296
2297 Constant *ConstantExpr::getURem(Constant *C1, Constant *C2) {
2298   return get(Instruction::URem, C1, C2);
2299 }
2300
2301 Constant *ConstantExpr::getSRem(Constant *C1, Constant *C2) {
2302   return get(Instruction::SRem, C1, C2);
2303 }
2304
2305 Constant *ConstantExpr::getFRem(Constant *C1, Constant *C2) {
2306   return get(Instruction::FRem, C1, C2);
2307 }
2308
2309 Constant *ConstantExpr::getAnd(Constant *C1, Constant *C2) {
2310   return get(Instruction::And, C1, C2);
2311 }
2312
2313 Constant *ConstantExpr::getOr(Constant *C1, Constant *C2) {
2314   return get(Instruction::Or, C1, C2);
2315 }
2316
2317 Constant *ConstantExpr::getXor(Constant *C1, Constant *C2) {
2318   return get(Instruction::Xor, C1, C2);
2319 }
2320
2321 Constant *ConstantExpr::getShl(Constant *C1, Constant *C2,
2322                                bool HasNUW, bool HasNSW) {
2323   unsigned Flags = (HasNUW ? OverflowingBinaryOperator::NoUnsignedWrap : 0) |
2324                    (HasNSW ? OverflowingBinaryOperator::NoSignedWrap   : 0);
2325   return get(Instruction::Shl, C1, C2, Flags);
2326 }
2327
2328 Constant *ConstantExpr::getLShr(Constant *C1, Constant *C2, bool isExact) {
2329   return get(Instruction::LShr, C1, C2,
2330              isExact ? PossiblyExactOperator::IsExact : 0);
2331 }
2332
2333 Constant *ConstantExpr::getAShr(Constant *C1, Constant *C2, bool isExact) {
2334   return get(Instruction::AShr, C1, C2,
2335              isExact ? PossiblyExactOperator::IsExact : 0);
2336 }
2337
2338 Constant *ConstantExpr::getBinOpIdentity(unsigned Opcode, Type *Ty,
2339                                          bool AllowRHSConstant) {
2340   assert(Instruction::isBinaryOp(Opcode) && "Only binops allowed");
2341
2342   // Commutative opcodes: it does not matter if AllowRHSConstant is set.
2343   if (Instruction::isCommutative(Opcode)) {
2344     switch (Opcode) {
2345       case Instruction::Add: // X + 0 = X
2346       case Instruction::Or:  // X | 0 = X
2347       case Instruction::Xor: // X ^ 0 = X
2348         return Constant::getNullValue(Ty);
2349       case Instruction::Mul: // X * 1 = X
2350         return ConstantInt::get(Ty, 1);
2351       case Instruction::And: // X & -1 = X
2352         return Constant::getAllOnesValue(Ty);
2353       case Instruction::FAdd: // X + -0.0 = X
2354         // TODO: If the fadd has 'nsz', should we return +0.0?
2355         return ConstantFP::getNegativeZero(Ty);
2356       case Instruction::FMul: // X * 1.0 = X
2357         return ConstantFP::get(Ty, 1.0);
2358       default:
2359         llvm_unreachable("Every commutative binop has an identity constant");
2360     }
2361   }
2362
2363   // Non-commutative opcodes: AllowRHSConstant must be set.
2364   if (!AllowRHSConstant)
2365     return nullptr;
2366
2367   switch (Opcode) {
2368     case Instruction::Sub:  // X - 0 = X
2369     case Instruction::Shl:  // X << 0 = X
2370     case Instruction::LShr: // X >>u 0 = X
2371     case Instruction::AShr: // X >> 0 = X
2372     case Instruction::FSub: // X - 0.0 = X
2373       return Constant::getNullValue(Ty);
2374     case Instruction::SDiv: // X / 1 = X
2375     case Instruction::UDiv: // X /u 1 = X
2376       return ConstantInt::get(Ty, 1);
2377     case Instruction::FDiv: // X / 1.0 = X
2378       return ConstantFP::get(Ty, 1.0);
2379     default:
2380       return nullptr;
2381   }
2382 }
2383
2384 Constant *ConstantExpr::getBinOpAbsorber(unsigned Opcode, Type *Ty) {
2385   switch (Opcode) {
2386   default:
2387     // Doesn't have an absorber.
2388     return nullptr;
2389
2390   case Instruction::Or:
2391     return Constant::getAllOnesValue(Ty);
2392
2393   case Instruction::And:
2394   case Instruction::Mul:
2395     return Constant::getNullValue(Ty);
2396   }
2397 }
2398
2399 /// Remove the constant from the constant table.
2400 void ConstantExpr::destroyConstantImpl() {
2401   getType()->getContext().pImpl->ExprConstants.remove(this);
2402 }
2403
2404 const char *ConstantExpr::getOpcodeName() const {
2405   return Instruction::getOpcodeName(getOpcode());
2406 }
2407
2408 GetElementPtrConstantExpr::GetElementPtrConstantExpr(
2409     Type *SrcElementTy, Constant *C, ArrayRef<Constant *> IdxList, Type *DestTy)
2410     : ConstantExpr(DestTy, Instruction::GetElementPtr,
2411                    OperandTraits<GetElementPtrConstantExpr>::op_end(this) -
2412                        (IdxList.size() + 1),
2413                    IdxList.size() + 1),
2414       SrcElementTy(SrcElementTy),
2415       ResElementTy(GetElementPtrInst::getIndexedType(SrcElementTy, IdxList)) {
2416   Op<0>() = C;
2417   Use *OperandList = getOperandList();
2418   for (unsigned i = 0, E = IdxList.size(); i != E; ++i)
2419     OperandList[i+1] = IdxList[i];
2420 }
2421
2422 Type *GetElementPtrConstantExpr::getSourceElementType() const {
2423   return SrcElementTy;
2424 }
2425
2426 Type *GetElementPtrConstantExpr::getResultElementType() const {
2427   return ResElementTy;
2428 }
2429
2430 //===----------------------------------------------------------------------===//
2431 //                       ConstantData* implementations
2432
2433 Type *ConstantDataSequential::getElementType() const {
2434   return getType()->getElementType();
2435 }
2436
2437 StringRef ConstantDataSequential::getRawDataValues() const {
2438   return StringRef(DataElements, getNumElements()*getElementByteSize());
2439 }
2440
2441 bool ConstantDataSequential::isElementTypeCompatible(Type *Ty) {
2442   if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) return true;
2443   if (auto *IT = dyn_cast<IntegerType>(Ty)) {
2444     switch (IT->getBitWidth()) {
2445     case 8:
2446     case 16:
2447     case 32:
2448     case 64:
2449       return true;
2450     default: break;
2451     }
2452   }
2453   return false;
2454 }
2455
2456 unsigned ConstantDataSequential::getNumElements() const {
2457   if (ArrayType *AT = dyn_cast<ArrayType>(getType()))
2458     return AT->getNumElements();
2459   return getType()->getVectorNumElements();
2460 }
2461
2462
2463 uint64_t ConstantDataSequential::getElementByteSize() const {
2464   return getElementType()->getPrimitiveSizeInBits()/8;
2465 }
2466
2467 /// Return the start of the specified element.
2468 const char *ConstantDataSequential::getElementPointer(unsigned Elt) const {
2469   assert(Elt < getNumElements() && "Invalid Elt");
2470   return DataElements+Elt*getElementByteSize();
2471 }
2472
2473
2474 /// Return true if the array is empty or all zeros.
2475 static bool isAllZeros(StringRef Arr) {
2476   for (char I : Arr)
2477     if (I != 0)
2478       return false;
2479   return true;
2480 }
2481
2482 /// This is the underlying implementation of all of the
2483 /// ConstantDataSequential::get methods.  They all thunk down to here, providing
2484 /// the correct element type.  We take the bytes in as a StringRef because
2485 /// we *want* an underlying "char*" to avoid TBAA type punning violations.
2486 Constant *ConstantDataSequential::getImpl(StringRef Elements, Type *Ty) {
2487   assert(isElementTypeCompatible(Ty->getSequentialElementType()));
2488   // If the elements are all zero or there are no elements, return a CAZ, which
2489   // is more dense and canonical.
2490   if (isAllZeros(Elements))
2491     return ConstantAggregateZero::get(Ty);
2492
2493   // Do a lookup to see if we have already formed one of these.
2494   auto &Slot =
2495       *Ty->getContext()
2496            .pImpl->CDSConstants.insert(std::make_pair(Elements, nullptr))
2497            .first;
2498
2499   // The bucket can point to a linked list of different CDS's that have the same
2500   // body but different types.  For example, 0,0,0,1 could be a 4 element array
2501   // of i8, or a 1-element array of i32.  They'll both end up in the same
2502   /// StringMap bucket, linked up by their Next pointers.  Walk the list.
2503   ConstantDataSequential **Entry = &Slot.second;
2504   for (ConstantDataSequential *Node = *Entry; Node;
2505        Entry = &Node->Next, Node = *Entry)
2506     if (Node->getType() == Ty)
2507       return Node;
2508
2509   // Okay, we didn't get a hit.  Create a node of the right class, link it in,
2510   // and return it.
2511   if (isa<ArrayType>(Ty))
2512     return *Entry = new ConstantDataArray(Ty, Slot.first().data());
2513
2514   assert(isa<VectorType>(Ty));
2515   return *Entry = new ConstantDataVector(Ty, Slot.first().data());
2516 }
2517
2518 void ConstantDataSequential::destroyConstantImpl() {
2519   // Remove the constant from the StringMap.
2520   StringMap<ConstantDataSequential*> &CDSConstants =
2521     getType()->getContext().pImpl->CDSConstants;
2522
2523   StringMap<ConstantDataSequential*>::iterator Slot =
2524     CDSConstants.find(getRawDataValues());
2525
2526   assert(Slot != CDSConstants.end() && "CDS not found in uniquing table");
2527
2528   ConstantDataSequential **Entry = &Slot->getValue();
2529
2530   // Remove the entry from the hash table.
2531   if (!(*Entry)->Next) {
2532     // If there is only one value in the bucket (common case) it must be this
2533     // entry, and removing the entry should remove the bucket completely.
2534     assert((*Entry) == this && "Hash mismatch in ConstantDataSequential");
2535     getContext().pImpl->CDSConstants.erase(Slot);
2536   } else {
2537     // Otherwise, there are multiple entries linked off the bucket, unlink the
2538     // node we care about but keep the bucket around.
2539     for (ConstantDataSequential *Node = *Entry; ;
2540          Entry = &Node->Next, Node = *Entry) {
2541       assert(Node && "Didn't find entry in its uniquing hash table!");
2542       // If we found our entry, unlink it from the list and we're done.
2543       if (Node == this) {
2544         *Entry = Node->Next;
2545         break;
2546       }
2547     }
2548   }
2549
2550   // If we were part of a list, make sure that we don't delete the list that is
2551   // still owned by the uniquing map.
2552   Next = nullptr;
2553 }
2554
2555 /// getFP() constructors - Return a constant with array type with an element
2556 /// count and element type of float with precision matching the number of
2557 /// bits in the ArrayRef passed in. (i.e. half for 16bits, float for 32bits,
2558 /// double for 64bits) Note that this can return a ConstantAggregateZero
2559 /// object.
2560 Constant *ConstantDataArray::getFP(LLVMContext &Context,
2561                                    ArrayRef<uint16_t> Elts) {
2562   Type *Ty = ArrayType::get(Type::getHalfTy(Context), Elts.size());
2563   const char *Data = reinterpret_cast<const char *>(Elts.data());
2564   return getImpl(StringRef(Data, Elts.size() * 2), Ty);
2565 }
2566 Constant *ConstantDataArray::getFP(LLVMContext &Context,
2567                                    ArrayRef<uint32_t> Elts) {
2568   Type *Ty = ArrayType::get(Type::getFloatTy(Context), Elts.size());
2569   const char *Data = reinterpret_cast<const char *>(Elts.data());
2570   return getImpl(StringRef(Data, Elts.size() * 4), Ty);
2571 }
2572 Constant *ConstantDataArray::getFP(LLVMContext &Context,
2573                                    ArrayRef<uint64_t> Elts) {
2574   Type *Ty = ArrayType::get(Type::getDoubleTy(Context), Elts.size());
2575   const char *Data = reinterpret_cast<const char *>(Elts.data());
2576   return getImpl(StringRef(Data, Elts.size() * 8), Ty);
2577 }
2578
2579 Constant *ConstantDataArray::getString(LLVMContext &Context,
2580                                        StringRef Str, bool AddNull) {
2581   if (!AddNull) {
2582     const uint8_t *Data = Str.bytes_begin();
2583     return get(Context, makeArrayRef(Data, Str.size()));
2584   }
2585
2586   SmallVector<uint8_t, 64> ElementVals;
2587   ElementVals.append(Str.begin(), Str.end());
2588   ElementVals.push_back(0);
2589   return get(Context, ElementVals);
2590 }
2591
2592 /// get() constructors - Return a constant with vector type with an element
2593 /// count and element type matching the ArrayRef passed in.  Note that this
2594 /// can return a ConstantAggregateZero object.
2595 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<uint8_t> Elts){
2596   Type *Ty = VectorType::get(Type::getInt8Ty(Context), Elts.size());
2597   const char *Data = reinterpret_cast<const char *>(Elts.data());
2598   return getImpl(StringRef(Data, Elts.size() * 1), Ty);
2599 }
2600 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<uint16_t> Elts){
2601   Type *Ty = VectorType::get(Type::getInt16Ty(Context), Elts.size());
2602   const char *Data = reinterpret_cast<const char *>(Elts.data());
2603   return getImpl(StringRef(Data, Elts.size() * 2), Ty);
2604 }
2605 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<uint32_t> Elts){
2606   Type *Ty = VectorType::get(Type::getInt32Ty(Context), Elts.size());
2607   const char *Data = reinterpret_cast<const char *>(Elts.data());
2608   return getImpl(StringRef(Data, Elts.size() * 4), Ty);
2609 }
2610 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<uint64_t> Elts){
2611   Type *Ty = VectorType::get(Type::getInt64Ty(Context), Elts.size());
2612   const char *Data = reinterpret_cast<const char *>(Elts.data());
2613   return getImpl(StringRef(Data, Elts.size() * 8), Ty);
2614 }
2615 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<float> Elts) {
2616   Type *Ty = VectorType::get(Type::getFloatTy(Context), Elts.size());
2617   const char *Data = reinterpret_cast<const char *>(Elts.data());
2618   return getImpl(StringRef(Data, Elts.size() * 4), Ty);
2619 }
2620 Constant *ConstantDataVector::get(LLVMContext &Context, ArrayRef<double> Elts) {
2621   Type *Ty = VectorType::get(Type::getDoubleTy(Context), Elts.size());
2622   const char *Data = reinterpret_cast<const char *>(Elts.data());
2623   return getImpl(StringRef(Data, Elts.size() * 8), Ty);
2624 }
2625
2626 /// getFP() constructors - Return a constant with vector type with an element
2627 /// count and element type of float with the precision matching the number of
2628 /// bits in the ArrayRef passed in.  (i.e. half for 16bits, float for 32bits,
2629 /// double for 64bits) Note that this can return a ConstantAggregateZero
2630 /// object.
2631 Constant *ConstantDataVector::getFP(LLVMContext &Context,
2632                                     ArrayRef<uint16_t> Elts) {
2633   Type *Ty = VectorType::get(Type::getHalfTy(Context), Elts.size());
2634   const char *Data = reinterpret_cast<const char *>(Elts.data());
2635   return getImpl(StringRef(Data, Elts.size() * 2), Ty);
2636 }
2637 Constant *ConstantDataVector::getFP(LLVMContext &Context,
2638                                     ArrayRef<uint32_t> Elts) {
2639   Type *Ty = VectorType::get(Type::getFloatTy(Context), Elts.size());
2640   const char *Data = reinterpret_cast<const char *>(Elts.data());
2641   return getImpl(StringRef(Data, Elts.size() * 4), Ty);
2642 }
2643 Constant *ConstantDataVector::getFP(LLVMContext &Context,
2644                                     ArrayRef<uint64_t> Elts) {
2645   Type *Ty = VectorType::get(Type::getDoubleTy(Context), Elts.size());
2646   const char *Data = reinterpret_cast<const char *>(Elts.data());
2647   return getImpl(StringRef(Data, Elts.size() * 8), Ty);
2648 }
2649
2650 Constant *ConstantDataVector::getSplat(unsigned NumElts, Constant *V) {
2651   assert(isElementTypeCompatible(V->getType()) &&
2652          "Element type not compatible with ConstantData");
2653   if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
2654     if (CI->getType()->isIntegerTy(8)) {
2655       SmallVector<uint8_t, 16> Elts(NumElts, CI->getZExtValue());
2656       return get(V->getContext(), Elts);
2657     }
2658     if (CI->getType()->isIntegerTy(16)) {
2659       SmallVector<uint16_t, 16> Elts(NumElts, CI->getZExtValue());
2660       return get(V->getContext(), Elts);
2661     }
2662     if (CI->getType()->isIntegerTy(32)) {
2663       SmallVector<uint32_t, 16> Elts(NumElts, CI->getZExtValue());
2664       return get(V->getContext(), Elts);
2665     }
2666     assert(CI->getType()->isIntegerTy(64) && "Unsupported ConstantData type");
2667     SmallVector<uint64_t, 16> Elts(NumElts, CI->getZExtValue());
2668     return get(V->getContext(), Elts);
2669   }
2670
2671   if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
2672     if (CFP->getType()->isHalfTy()) {
2673       SmallVector<uint16_t, 16> Elts(
2674           NumElts, CFP->getValueAPF().bitcastToAPInt().getLimitedValue());
2675       return getFP(V->getContext(), Elts);
2676     }
2677     if (CFP->getType()->isFloatTy()) {
2678       SmallVector<uint32_t, 16> Elts(
2679           NumElts, CFP->getValueAPF().bitcastToAPInt().getLimitedValue());
2680       return getFP(V->getContext(), Elts);
2681     }
2682     if (CFP->getType()->isDoubleTy()) {
2683       SmallVector<uint64_t, 16> Elts(
2684           NumElts, CFP->getValueAPF().bitcastToAPInt().getLimitedValue());
2685       return getFP(V->getContext(), Elts);
2686     }
2687   }
2688   return ConstantVector::getSplat(NumElts, V);
2689 }
2690
2691
2692 uint64_t ConstantDataSequential::getElementAsInteger(unsigned Elt) const {
2693   assert(isa<IntegerType>(getElementType()) &&
2694          "Accessor can only be used when element is an integer");
2695   const char *EltPtr = getElementPointer(Elt);
2696
2697   // The data is stored in host byte order, make sure to cast back to the right
2698   // type to load with the right endianness.
2699   switch (getElementType()->getIntegerBitWidth()) {
2700   default: llvm_unreachable("Invalid bitwidth for CDS");
2701   case 8:
2702     return *reinterpret_cast<const uint8_t *>(EltPtr);
2703   case 16:
2704     return *reinterpret_cast<const uint16_t *>(EltPtr);
2705   case 32:
2706     return *reinterpret_cast<const uint32_t *>(EltPtr);
2707   case 64:
2708     return *reinterpret_cast<const uint64_t *>(EltPtr);
2709   }
2710 }
2711
2712 APInt ConstantDataSequential::getElementAsAPInt(unsigned Elt) const {
2713   assert(isa<IntegerType>(getElementType()) &&
2714          "Accessor can only be used when element is an integer");
2715   const char *EltPtr = getElementPointer(Elt);
2716
2717   // The data is stored in host byte order, make sure to cast back to the right
2718   // type to load with the right endianness.
2719   switch (getElementType()->getIntegerBitWidth()) {
2720   default: llvm_unreachable("Invalid bitwidth for CDS");
2721   case 8: {
2722     auto EltVal = *reinterpret_cast<const uint8_t *>(EltPtr);
2723     return APInt(8, EltVal);
2724   }
2725   case 16: {
2726     auto EltVal = *reinterpret_cast<const uint16_t *>(EltPtr);
2727     return APInt(16, EltVal);
2728   }
2729   case 32: {
2730     auto EltVal = *reinterpret_cast<const uint32_t *>(EltPtr);
2731     return APInt(32, EltVal);
2732   }
2733   case 64: {
2734     auto EltVal = *reinterpret_cast<const uint64_t *>(EltPtr);
2735     return APInt(64, EltVal);
2736   }
2737   }
2738 }
2739
2740 APFloat ConstantDataSequential::getElementAsAPFloat(unsigned Elt) const {
2741   const char *EltPtr = getElementPointer(Elt);
2742
2743   switch (getElementType()->getTypeID()) {
2744   default:
2745     llvm_unreachable("Accessor can only be used when element is float/double!");
2746   case Type::HalfTyID: {
2747     auto EltVal = *reinterpret_cast<const uint16_t *>(EltPtr);
2748     return APFloat(APFloat::IEEEhalf(), APInt(16, EltVal));
2749   }
2750   case Type::FloatTyID: {
2751     auto EltVal = *reinterpret_cast<const uint32_t *>(EltPtr);
2752     return APFloat(APFloat::IEEEsingle(), APInt(32, EltVal));
2753   }
2754   case Type::DoubleTyID: {
2755     auto EltVal = *reinterpret_cast<const uint64_t *>(EltPtr);
2756     return APFloat(APFloat::IEEEdouble(), APInt(64, EltVal));
2757   }
2758   }
2759 }
2760
2761 float ConstantDataSequential::getElementAsFloat(unsigned Elt) const {
2762   assert(getElementType()->isFloatTy() &&
2763          "Accessor can only be used when element is a 'float'");
2764   return *reinterpret_cast<const float *>(getElementPointer(Elt));
2765 }
2766
2767 double ConstantDataSequential::getElementAsDouble(unsigned Elt) const {
2768   assert(getElementType()->isDoubleTy() &&
2769          "Accessor can only be used when element is a 'float'");
2770   return *reinterpret_cast<const double *>(getElementPointer(Elt));
2771 }
2772
2773 Constant *ConstantDataSequential::getElementAsConstant(unsigned Elt) const {
2774   if (getElementType()->isHalfTy() || getElementType()->isFloatTy() ||
2775       getElementType()->isDoubleTy())
2776     return ConstantFP::get(getContext(), getElementAsAPFloat(Elt));
2777
2778   return ConstantInt::get(getElementType(), getElementAsInteger(Elt));
2779 }
2780
2781 bool ConstantDataSequential::isString(unsigned CharSize) const {
2782   return isa<ArrayType>(getType()) && getElementType()->isIntegerTy(CharSize);
2783 }
2784
2785 bool ConstantDataSequential::isCString() const {
2786   if (!isString())
2787     return false;
2788
2789   StringRef Str = getAsString();
2790
2791   // The last value must be nul.
2792   if (Str.back() != 0) return false;
2793
2794   // Other elements must be non-nul.
2795   return Str.drop_back().find(0) == StringRef::npos;
2796 }
2797
2798 bool ConstantDataVector::isSplat() const {
2799   const char *Base = getRawDataValues().data();
2800
2801   // Compare elements 1+ to the 0'th element.
2802   unsigned EltSize = getElementByteSize();
2803   for (unsigned i = 1, e = getNumElements(); i != e; ++i)
2804     if (memcmp(Base, Base+i*EltSize, EltSize))
2805       return false;
2806
2807   return true;
2808 }
2809
2810 Constant *ConstantDataVector::getSplatValue() const {
2811   // If they're all the same, return the 0th one as a representative.
2812   return isSplat() ? getElementAsConstant(0) : nullptr;
2813 }
2814
2815 //===----------------------------------------------------------------------===//
2816 //                handleOperandChange implementations
2817
2818 /// Update this constant array to change uses of
2819 /// 'From' to be uses of 'To'.  This must update the uniquing data structures
2820 /// etc.
2821 ///
2822 /// Note that we intentionally replace all uses of From with To here.  Consider
2823 /// a large array that uses 'From' 1000 times.  By handling this case all here,
2824 /// ConstantArray::handleOperandChange is only invoked once, and that
2825 /// single invocation handles all 1000 uses.  Handling them one at a time would
2826 /// work, but would be really slow because it would have to unique each updated
2827 /// array instance.
2828 ///
2829 void Constant::handleOperandChange(Value *From, Value *To) {
2830   Value *Replacement = nullptr;
2831   switch (getValueID()) {
2832   default:
2833     llvm_unreachable("Not a constant!");
2834 #define HANDLE_CONSTANT(Name)                                                  \
2835   case Value::Name##Val:                                                       \
2836     Replacement = cast<Name>(this)->handleOperandChangeImpl(From, To);         \
2837     break;
2838 #include "llvm/IR/Value.def"
2839   }
2840
2841   // If handleOperandChangeImpl returned nullptr, then it handled
2842   // replacing itself and we don't want to delete or replace anything else here.
2843   if (!Replacement)
2844     return;
2845
2846   // I do need to replace this with an existing value.
2847   assert(Replacement != this && "I didn't contain From!");
2848
2849   // Everyone using this now uses the replacement.
2850   replaceAllUsesWith(Replacement);
2851
2852   // Delete the old constant!
2853   destroyConstant();
2854 }
2855
2856 Value *ConstantArray::handleOperandChangeImpl(Value *From, Value *To) {
2857   assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
2858   Constant *ToC = cast<Constant>(To);
2859
2860   SmallVector<Constant*, 8> Values;
2861   Values.reserve(getNumOperands());  // Build replacement array.
2862
2863   // Fill values with the modified operands of the constant array.  Also,
2864   // compute whether this turns into an all-zeros array.
2865   unsigned NumUpdated = 0;
2866
2867   // Keep track of whether all the values in the array are "ToC".
2868   bool AllSame = true;
2869   Use *OperandList = getOperandList();
2870   unsigned OperandNo = 0;
2871   for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O) {
2872     Constant *Val = cast<Constant>(O->get());
2873     if (Val == From) {
2874       OperandNo = (O - OperandList);
2875       Val = ToC;
2876       ++NumUpdated;
2877     }
2878     Values.push_back(Val);
2879     AllSame &= Val == ToC;
2880   }
2881
2882   if (AllSame && ToC->isNullValue())
2883     return ConstantAggregateZero::get(getType());
2884
2885   if (AllSame && isa<UndefValue>(ToC))
2886     return UndefValue::get(getType());
2887
2888   // Check for any other type of constant-folding.
2889   if (Constant *C = getImpl(getType(), Values))
2890     return C;
2891
2892   // Update to the new value.
2893   return getContext().pImpl->ArrayConstants.replaceOperandsInPlace(
2894       Values, this, From, ToC, NumUpdated, OperandNo);
2895 }
2896
2897 Value *ConstantStruct::handleOperandChangeImpl(Value *From, Value *To) {
2898   assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
2899   Constant *ToC = cast<Constant>(To);
2900
2901   Use *OperandList = getOperandList();
2902
2903   SmallVector<Constant*, 8> Values;
2904   Values.reserve(getNumOperands());  // Build replacement struct.
2905
2906   // Fill values with the modified operands of the constant struct.  Also,
2907   // compute whether this turns into an all-zeros struct.
2908   unsigned NumUpdated = 0;
2909   bool AllSame = true;
2910   unsigned OperandNo = 0;
2911   for (Use *O = OperandList, *E = OperandList + getNumOperands(); O != E; ++O) {
2912     Constant *Val = cast<Constant>(O->get());
2913     if (Val == From) {
2914       OperandNo = (O - OperandList);
2915       Val = ToC;
2916       ++NumUpdated;
2917     }
2918     Values.push_back(Val);
2919     AllSame &= Val == ToC;
2920   }
2921
2922   if (AllSame && ToC->isNullValue())
2923     return ConstantAggregateZero::get(getType());
2924
2925   if (AllSame && isa<UndefValue>(ToC))
2926     return UndefValue::get(getType());
2927
2928   // Update to the new value.
2929   return getContext().pImpl->StructConstants.replaceOperandsInPlace(
2930       Values, this, From, ToC, NumUpdated, OperandNo);
2931 }
2932
2933 Value *ConstantVector::handleOperandChangeImpl(Value *From, Value *To) {
2934   assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
2935   Constant *ToC = cast<Constant>(To);
2936
2937   SmallVector<Constant*, 8> Values;
2938   Values.reserve(getNumOperands());  // Build replacement array...
2939   unsigned NumUpdated = 0;
2940   unsigned OperandNo = 0;
2941   for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
2942     Constant *Val = getOperand(i);
2943     if (Val == From) {
2944       OperandNo = i;
2945       ++NumUpdated;
2946       Val = ToC;
2947     }
2948     Values.push_back(Val);
2949   }
2950
2951   if (Constant *C = getImpl(Values))
2952     return C;
2953
2954   // Update to the new value.
2955   return getContext().pImpl->VectorConstants.replaceOperandsInPlace(
2956       Values, this, From, ToC, NumUpdated, OperandNo);
2957 }
2958
2959 Value *ConstantExpr::handleOperandChangeImpl(Value *From, Value *ToV) {
2960   assert(isa<Constant>(ToV) && "Cannot make Constant refer to non-constant!");
2961   Constant *To = cast<Constant>(ToV);
2962
2963   SmallVector<Constant*, 8> NewOps;
2964   unsigned NumUpdated = 0;
2965   unsigned OperandNo = 0;
2966   for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
2967     Constant *Op = getOperand(i);
2968     if (Op == From) {
2969       OperandNo = i;
2970       ++NumUpdated;
2971       Op = To;
2972     }
2973     NewOps.push_back(Op);
2974   }
2975   assert(NumUpdated && "I didn't contain From!");
2976
2977   if (Constant *C = getWithOperands(NewOps, getType(), true))
2978     return C;
2979
2980   // Update to the new value.
2981   return getContext().pImpl->ExprConstants.replaceOperandsInPlace(
2982       NewOps, this, From, To, NumUpdated, OperandNo);
2983 }
2984
2985 Instruction *ConstantExpr::getAsInstruction() {
2986   SmallVector<Value *, 4> ValueOperands(op_begin(), op_end());
2987   ArrayRef<Value*> Ops(ValueOperands);
2988
2989   switch (getOpcode()) {
2990   case Instruction::Trunc:
2991   case Instruction::ZExt:
2992   case Instruction::SExt:
2993   case Instruction::FPTrunc:
2994   case Instruction::FPExt:
2995   case Instruction::UIToFP:
2996   case Instruction::SIToFP:
2997   case Instruction::FPToUI:
2998   case Instruction::FPToSI:
2999   case Instruction::PtrToInt:
3000   case Instruction::IntToPtr:
3001   case Instruction::BitCast:
3002   case Instruction::AddrSpaceCast:
3003     return CastInst::Create((Instruction::CastOps)getOpcode(),
3004                             Ops[0], getType());
3005   case Instruction::Select:
3006     return SelectInst::Create(Ops[0], Ops[1], Ops[2]);
3007   case Instruction::InsertElement:
3008     return InsertElementInst::Create(Ops[0], Ops[1], Ops[2]);
3009   case Instruction::ExtractElement:
3010     return ExtractElementInst::Create(Ops[0], Ops[1]);
3011   case Instruction::InsertValue:
3012     return InsertValueInst::Create(Ops[0], Ops[1], getIndices());
3013   case Instruction::ExtractValue:
3014     return ExtractValueInst::Create(Ops[0], getIndices());
3015   case Instruction::ShuffleVector:
3016     return new ShuffleVectorInst(Ops[0], Ops[1], Ops[2]);
3017
3018   case Instruction::GetElementPtr: {
3019     const auto *GO = cast<GEPOperator>(this);
3020     if (GO->isInBounds())
3021       return GetElementPtrInst::CreateInBounds(GO->getSourceElementType(),
3022                                                Ops[0], Ops.slice(1));
3023     return GetElementPtrInst::Create(GO->getSourceElementType(), Ops[0],
3024                                      Ops.slice(1));
3025   }
3026   case Instruction::ICmp:
3027   case Instruction::FCmp:
3028     return CmpInst::Create((Instruction::OtherOps)getOpcode(),
3029                            (CmpInst::Predicate)getPredicate(), Ops[0], Ops[1]);
3030   case Instruction::FNeg:
3031     return UnaryOperator::Create((Instruction::UnaryOps)getOpcode(), Ops[0]);
3032   default:
3033     assert(getNumOperands() == 2 && "Must be binary operator?");
3034     BinaryOperator *BO =
3035       BinaryOperator::Create((Instruction::BinaryOps)getOpcode(),
3036                              Ops[0], Ops[1]);
3037     if (isa<OverflowingBinaryOperator>(BO)) {
3038       BO->setHasNoUnsignedWrap(SubclassOptionalData &
3039                                OverflowingBinaryOperator::NoUnsignedWrap);
3040       BO->setHasNoSignedWrap(SubclassOptionalData &
3041                              OverflowingBinaryOperator::NoSignedWrap);
3042     }
3043     if (isa<PossiblyExactOperator>(BO))
3044       BO->setIsExact(SubclassOptionalData & PossiblyExactOperator::IsExact);
3045     return BO;
3046   }
3047 }