LCOV - code coverage report
Current view: top level - lib/IR - ConstantFold.cpp (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 931 1058 88.0 %
Date: 2017-09-14 15:23:50 Functions: 25 25 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===- ConstantFold.cpp - LLVM constant folder ----------------------------===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : //
      10             : // This file implements folding of constants for LLVM.  This implements the
      11             : // (internal) ConstantFold.h interface, which is used by the
      12             : // ConstantExpr::get* methods to automatically fold constants when possible.
      13             : //
      14             : // The current constant folding implementation is implemented in two pieces: the
      15             : // pieces that don't need DataLayout, and the pieces that do. This is to avoid
      16             : // a dependence in IR on Target.
      17             : //
      18             : //===----------------------------------------------------------------------===//
      19             : 
      20             : #include "ConstantFold.h"
      21             : #include "llvm/ADT/APSInt.h"
      22             : #include "llvm/ADT/SmallVector.h"
      23             : #include "llvm/IR/Constants.h"
      24             : #include "llvm/IR/DerivedTypes.h"
      25             : #include "llvm/IR/Function.h"
      26             : #include "llvm/IR/GetElementPtrTypeIterator.h"
      27             : #include "llvm/IR/GlobalAlias.h"
      28             : #include "llvm/IR/GlobalVariable.h"
      29             : #include "llvm/IR/Instructions.h"
      30             : #include "llvm/IR/Operator.h"
      31             : #include "llvm/IR/PatternMatch.h"
      32             : #include "llvm/Support/ErrorHandling.h"
      33             : #include "llvm/Support/ManagedStatic.h"
      34             : #include "llvm/Support/MathExtras.h"
      35             : using namespace llvm;
      36             : using namespace llvm::PatternMatch;
      37             : 
      38             : //===----------------------------------------------------------------------===//
      39             : //                ConstantFold*Instruction Implementations
      40             : //===----------------------------------------------------------------------===//
      41             : 
      42             : /// Convert the specified vector Constant node to the specified vector type.
      43             : /// At this point, we know that the elements of the input vector constant are
      44             : /// all simple integer or FP values.
      45          92 : static Constant *BitCastConstantVector(Constant *CV, VectorType *DstTy) {
      46             : 
      47          92 :   if (CV->isAllOnesValue()) return Constant::getAllOnesValue(DstTy);
      48          76 :   if (CV->isNullValue()) return Constant::getNullValue(DstTy);
      49             : 
      50             :   // If this cast changes element count then we can't handle it here:
      51             :   // doing so requires endianness information.  This should be handled by
      52             :   // Analysis/ConstantFolding.cpp
      53          76 :   unsigned NumElts = DstTy->getNumElements();
      54         152 :   if (NumElts != CV->getType()->getVectorNumElements())
      55             :     return nullptr;
      56             : 
      57           0 :   Type *DstEltTy = DstTy->getElementType();
      58             : 
      59           0 :   SmallVector<Constant*, 16> Result;
      60           0 :   Type *Ty = IntegerType::get(CV->getContext(), 32);
      61           0 :   for (unsigned i = 0; i != NumElts; ++i) {
      62             :     Constant *C =
      63           0 :       ConstantExpr::getExtractElement(CV, ConstantInt::get(Ty, i));
      64           0 :     C = ConstantExpr::getBitCast(C, DstEltTy);
      65           0 :     Result.push_back(C);
      66             :   }
      67             : 
      68           0 :   return ConstantVector::get(Result);
      69             : }
      70             : 
      71             : /// This function determines which opcode to use to fold two constant cast
      72             : /// expressions together. It uses CastInst::isEliminableCastPair to determine
      73             : /// the opcode. Consequently its just a wrapper around that function.
      74             : /// @brief Determine if it is valid to fold a cast of a cast
      75             : static unsigned
      76      500003 : foldConstantCastPair(
      77             :   unsigned opc,          ///< opcode of the second cast constant expression
      78             :   ConstantExpr *Op,      ///< the first cast constant expression
      79             :   Type *DstTy            ///< destination type of the first cast
      80             : ) {
      81             :   assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!");
      82             :   assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type");
      83             :   assert(CastInst::isCast(opc) && "Invalid cast opcode");
      84             : 
      85             :   // The types and opcodes for the two Cast constant expressions
      86      500003 :   Type *SrcTy = Op->getOperand(0)->getType();
      87      500003 :   Type *MidTy = Op->getType();
      88      500003 :   Instruction::CastOps firstOp = Instruction::CastOps(Op->getOpcode());
      89      500003 :   Instruction::CastOps secondOp = Instruction::CastOps(opc);
      90             : 
      91             :   // Assume that pointers are never more than 64 bits wide, and only use this
      92             :   // for the middle type. Otherwise we could end up folding away illegal
      93             :   // bitcasts between address spaces with different sizes.
      94      500003 :   IntegerType *FakeIntPtrTy = Type::getInt64Ty(DstTy->getContext());
      95             : 
      96             :   // Let CastInst::isEliminableCastPair do the heavy lifting.
      97             :   return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
      98      500003 :                                         nullptr, FakeIntPtrTy, nullptr);
      99             : }
     100             : 
     101     1491841 : static Constant *FoldBitCast(Constant *V, Type *DestTy) {
     102     1491841 :   Type *SrcTy = V->getType();
     103     1491841 :   if (SrcTy == DestTy)
     104             :     return V; // no-op cast
     105             : 
     106             :   // Check to see if we are casting a pointer to an aggregate to a pointer to
     107             :   // the first element.  If so, return the appropriate GEP instruction.
     108     2981786 :   if (PointerType *PTy = dyn_cast<PointerType>(V->getType()))
     109     1489945 :     if (PointerType *DPTy = dyn_cast<PointerType>(DestTy))
     110     2979890 :       if (PTy->getAddressSpace() == DPTy->getAddressSpace()
     111     1489945 :           && PTy->getElementType()->isSized()) {
     112     2906437 :         SmallVector<Value*, 8> IdxList;
     113             :         Value *Zero =
     114     1459789 :           Constant::getNullValue(Type::getInt32Ty(DPTy->getContext()));
     115     1459789 :         IdxList.push_back(Zero);
     116     1459789 :         Type *ElTy = PTy->getElementType();
     117     2836624 :         while (ElTy != DPTy->getElementType()) {
     118       22176 :           if (StructType *STy = dyn_cast<StructType>(ElTy)) {
     119       22176 :             if (STy->getNumElements() == 0) break;
     120       44294 :             ElTy = STy->getElementType(0);
     121       22147 :             IdxList.push_back(Zero);
     122             :           } else if (SequentialType *STy =
     123     1354688 :                      dyn_cast<SequentialType>(ElTy)) {
     124     1354688 :             ElTy = STy->getElementType();
     125     1354688 :             IdxList.push_back(Zero);
     126             :           } else {
     127             :             break;
     128             :           }
     129             :         }
     130             : 
     131     1459789 :         if (ElTy == DPTy->getElementType())
     132             :           // This GEP is inbounds because all indices are zero.
     133       26282 :           return ConstantExpr::getInBoundsGetElementPtr(PTy->getElementType(),
     134       13141 :                                                         V, IdxList);
     135             :       }
     136             : 
     137             :   // Handle casts from one vector constant to another.  We know that the src
     138             :   // and dest type have the same size (otherwise its an illegal cast).
     139         126 :   if (VectorType *DestPTy = dyn_cast<VectorType>(DestTy)) {
     140         218 :     if (VectorType *SrcTy = dyn_cast<VectorType>(V->getType())) {
     141             :       assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
     142             :              "Not cast between same sized vectors!");
     143          92 :       SrcTy = nullptr;
     144             :       // First, check for null.  Undef is already handled.
     145         184 :       if (isa<ConstantAggregateZero>(V))
     146           0 :         return Constant::getNullValue(DestTy);
     147             : 
     148             :       // Handle ConstantVector and ConstantAggregateVector.
     149          92 :       return BitCastConstantVector(V, DestPTy);
     150             :     }
     151             : 
     152             :     // Canonicalize scalar-to-vector bitcasts into vector-to-vector bitcasts
     153             :     // This allows for other simplifications (although some of them
     154             :     // can only be handled by Analysis/ConstantFolding.cpp).
     155          98 :     if (isa<ConstantInt>(V) || isa<ConstantFP>(V))
     156           5 :       return ConstantExpr::getBitCast(ConstantVector::get(V), DestPTy);
     157             :   }
     158             : 
     159             :   // Finally, implement bitcast folding now.   The code below doesn't handle
     160             :   // bitcast right.
     161     2957206 :   if (isa<ConstantPointerNull>(V))  // ptr->ptr cast.
     162           0 :     return ConstantPointerNull::get(cast<PointerType>(DestTy));
     163             : 
     164             :   // Handle integral constant input.
     165     1478959 :   if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
     166         356 :     if (DestTy->isIntegerTy())
     167             :       // Integral -> Integral. This is a no-op because the bit widths must
     168             :       // be the same. Consequently, we just fold to V.
     169             :       return V;
     170             : 
     171             :     // See note below regarding the PPC_FP128 restriction.
     172         352 :     if (DestTy->isFloatingPointTy() && !DestTy->isPPC_FP128Ty())
     173         352 :       return ConstantFP::get(DestTy->getContext(),
     174        1056 :                              APFloat(DestTy->getFltSemantics(),
     175         352 :                                      CI->getValue()));
     176             : 
     177             :     // Otherwise, can't fold this (vector?)
     178             :     return nullptr;
     179             :   }
     180             : 
     181             :   // Handle ConstantFP input: FP -> Integral.
     182     1479533 :   if (ConstantFP *FP = dyn_cast<ConstantFP>(V)) {
     183             :     // PPC_FP128 is really the sum of two consecutive doubles, where the first
     184             :     // double is always stored first in memory, regardless of the target
     185             :     // endianness. The memory layout of i128, however, depends on the target
     186             :     // endianness, and so we can't fold this without target endianness
     187             :     // information. This should instead be handled by
     188             :     // Analysis/ConstantFolding.cpp
     189        2572 :     if (FP->getType()->isPPC_FP128Ty())
     190             :       return nullptr;
     191             : 
     192             :     // Make sure dest type is compatible with the folded integer constant.
     193        1277 :     if (!DestTy->isIntegerTy())
     194             :       return nullptr;
     195             : 
     196        1276 :     return ConstantInt::get(FP->getContext(),
     197        3828 :                             FP->getValueAPF().bitcastToAPInt());
     198             :   }
     199             : 
     200             :   return nullptr;
     201             : }
     202             : 
     203             : 
     204             : /// V is an integer constant which only has a subset of its bytes used.
     205             : /// The bytes used are indicated by ByteStart (which is the first byte used,
     206             : /// counting from the least significant byte) and ByteSize, which is the number
     207             : /// of bytes used.
     208             : ///
     209             : /// This function analyzes the specified constant to see if the specified byte
     210             : /// range can be returned as a simplified constant.  If so, the constant is
     211             : /// returned, otherwise null is returned.
     212        1055 : static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
     213             :                                       unsigned ByteSize) {
     214             :   assert(C->getType()->isIntegerTy() &&
     215             :          (cast<IntegerType>(C->getType())->getBitWidth() & 7) == 0 &&
     216             :          "Non-byte sized integer input");
     217        3165 :   unsigned CSize = cast<IntegerType>(C->getType())->getBitWidth()/8;
     218             :   assert(ByteSize && "Must be accessing some piece");
     219             :   assert(ByteStart+ByteSize <= CSize && "Extracting invalid piece from input");
     220             :   assert(ByteSize != CSize && "Should not extract everything");
     221             : 
     222             :   // Constant Integers are simple.
     223          18 :   if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
     224          54 :     APInt V = CI->getValue();
     225          18 :     if (ByteStart)
     226          13 :       V.lshrInPlace(ByteStart*8);
     227          54 :     V = V.trunc(ByteSize*8);
     228          18 :     return ConstantInt::get(CI->getContext(), V);
     229             :   }
     230             : 
     231             :   // In the input is a constant expr, we might be able to recursively simplify.
     232             :   // If not, we definitely can't do anything.
     233        1037 :   ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
     234             :   if (!CE) return nullptr;
     235             : 
     236        1037 :   switch (CE->getOpcode()) {
     237             :   default: return nullptr;
     238          14 :   case Instruction::Or: {
     239          14 :     Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
     240          14 :     if (!RHS)
     241             :       return nullptr;
     242             : 
     243             :     // X | -1 -> -1.
     244          12 :     if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS))
     245          12 :       if (RHSC->isMinusOne())
     246             :         return RHSC;
     247             : 
     248          14 :     Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
     249          14 :     if (!LHS)
     250             :       return nullptr;
     251           7 :     return ConstantExpr::getOr(LHS, RHS);
     252             :   }
     253          11 :   case Instruction::And: {
     254          11 :     Constant *RHS = ExtractConstantBytes(CE->getOperand(1), ByteStart,ByteSize);
     255          11 :     if (!RHS)
     256             :       return nullptr;
     257             : 
     258             :     // X & 0 -> 0.
     259          11 :     if (RHS->isNullValue())
     260             :       return RHS;
     261             : 
     262           7 :     Constant *LHS = ExtractConstantBytes(CE->getOperand(0), ByteStart,ByteSize);
     263           7 :     if (!LHS)
     264             :       return nullptr;
     265           3 :     return ConstantExpr::getAnd(LHS, RHS);
     266             :   }
     267          35 :   case Instruction::LShr: {
     268          70 :     ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
     269             :     if (!Amt)
     270             :       return nullptr;
     271          35 :     unsigned ShAmt = Amt->getZExtValue();
     272             :     // Cannot analyze non-byte shifts.
     273          35 :     if ((ShAmt & 7) != 0)
     274             :       return nullptr;
     275          35 :     ShAmt >>= 3;
     276             : 
     277             :     // If the extract is known to be all zeros, return zero.
     278          35 :     if (ByteStart >= CSize-ShAmt)
     279           0 :       return Constant::getNullValue(IntegerType::get(CE->getContext(),
     280           0 :                                                      ByteSize*8));
     281             :     // If the extract is known to be fully in the input, extract it.
     282          35 :     if (ByteStart+ByteSize+ShAmt <= CSize)
     283          70 :       return ExtractConstantBytes(CE->getOperand(0), ByteStart+ShAmt, ByteSize);
     284             : 
     285             :     // TODO: Handle the 'partially zero' case.
     286             :     return nullptr;
     287             :   }
     288             : 
     289          16 :   case Instruction::Shl: {
     290          32 :     ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
     291             :     if (!Amt)
     292             :       return nullptr;
     293          16 :     unsigned ShAmt = Amt->getZExtValue();
     294             :     // Cannot analyze non-byte shifts.
     295          16 :     if ((ShAmt & 7) != 0)
     296             :       return nullptr;
     297          16 :     ShAmt >>= 3;
     298             : 
     299             :     // If the extract is known to be all zeros, return zero.
     300          16 :     if (ByteStart+ByteSize <= ShAmt)
     301           5 :       return Constant::getNullValue(IntegerType::get(CE->getContext(),
     302           5 :                                                      ByteSize*8));
     303             :     // If the extract is known to be fully in the input, extract it.
     304          11 :     if (ByteStart >= ShAmt)
     305          10 :       return ExtractConstantBytes(CE->getOperand(0), ByteStart-ShAmt, ByteSize);
     306             : 
     307             :     // TODO: Handle the 'partially zero' case.
     308             :     return nullptr;
     309             :   }
     310             : 
     311          12 :   case Instruction::ZExt: {
     312             :     unsigned SrcBitSize =
     313          36 :       cast<IntegerType>(CE->getOperand(0)->getType())->getBitWidth();
     314             : 
     315             :     // If extracting something that is completely zero, return 0.
     316          12 :     if (ByteStart*8 >= SrcBitSize)
     317           6 :       return Constant::getNullValue(IntegerType::get(CE->getContext(),
     318           6 :                                                      ByteSize*8));
     319             : 
     320             :     // If exactly extracting the input, return it.
     321           6 :     if (ByteStart == 0 && ByteSize*8 == SrcBitSize)
     322             :       return CE->getOperand(0);
     323             : 
     324             :     // If extracting something completely in the input, if if the input is a
     325             :     // multiple of 8 bits, recurse.
     326           1 :     if ((SrcBitSize&7) == 0 && (ByteStart+ByteSize)*8 <= SrcBitSize)
     327           0 :       return ExtractConstantBytes(CE->getOperand(0), ByteStart, ByteSize);
     328             : 
     329             :     // Otherwise, if extracting a subset of the input, which is not multiple of
     330             :     // 8 bits, do a shift and trunc to get the bits.
     331           1 :     if ((ByteStart+ByteSize)*8 < SrcBitSize) {
     332             :       assert((SrcBitSize&7) && "Shouldn't get byte sized case here");
     333           0 :       Constant *Res = CE->getOperand(0);
     334           0 :       if (ByteStart)
     335           0 :         Res = ConstantExpr::getLShr(Res,
     336             :                                  ConstantInt::get(Res->getType(), ByteStart*8));
     337           0 :       return ConstantExpr::getTrunc(Res, IntegerType::get(C->getContext(),
     338           0 :                                                           ByteSize*8));
     339             :     }
     340             : 
     341             :     // TODO: Handle the 'partially zero' case.
     342             :     return nullptr;
     343             :   }
     344             :   }
     345             : }
     346             : 
     347             : /// Return a ConstantExpr with type DestTy for sizeof on Ty, with any known
     348             : /// factors factored out. If Folded is false, return null if no factoring was
     349             : /// possible, to avoid endlessly bouncing an unfoldable expression back into the
     350             : /// top-level folder.
     351         609 : static Constant *getFoldedSizeOf(Type *Ty, Type *DestTy, bool Folded) {
     352          21 :   if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
     353          21 :     Constant *N = ConstantInt::get(DestTy, ATy->getNumElements());
     354          21 :     Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
     355          21 :     return ConstantExpr::getNUWMul(E, N);
     356             :   }
     357             : 
     358         119 :   if (StructType *STy = dyn_cast<StructType>(Ty))
     359         119 :     if (!STy->isPacked()) {
     360         119 :       unsigned NumElems = STy->getNumElements();
     361             :       // An empty struct has size zero.
     362         119 :       if (NumElems == 0)
     363           0 :         return ConstantExpr::getNullValue(DestTy);
     364             :       // Check for a struct with all members having the same size.
     365             :       Constant *MemberSize =
     366         238 :         getFoldedSizeOf(STy->getElementType(0), DestTy, true);
     367         119 :       bool AllSame = true;
     368         132 :       for (unsigned i = 1; i != NumElems; ++i)
     369          38 :         if (MemberSize !=
     370          76 :             getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
     371             :           AllSame = false;
     372             :           break;
     373             :         }
     374         119 :       if (AllSame) {
     375          94 :         Constant *N = ConstantInt::get(DestTy, NumElems);
     376          94 :         return ConstantExpr::getNUWMul(MemberSize, N);
     377             :       }
     378             :     }
     379             : 
     380             :   // Pointer size doesn't depend on the pointee type, so canonicalize them
     381             :   // to an arbitrary pointee.
     382          48 :   if (PointerType *PTy = dyn_cast<PointerType>(Ty))
     383          48 :     if (!PTy->getElementType()->isIntegerTy(1))
     384             :       return
     385          15 :         getFoldedSizeOf(PointerType::get(IntegerType::get(PTy->getContext(), 1),
     386             :                                          PTy->getAddressSpace()),
     387          15 :                         DestTy, true);
     388             : 
     389             :   // If there's no interesting folding happening, bail so that we don't create
     390             :   // a constant that looks like it needs folding but really doesn't.
     391         479 :   if (!Folded)
     392             :     return nullptr;
     393             : 
     394             :   // Base case: Get a regular sizeof expression.
     395         197 :   Constant *C = ConstantExpr::getSizeOf(Ty);
     396         197 :   C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
     397             :                                                     DestTy, false),
     398             :                             C, DestTy);
     399         197 :   return C;
     400             : }
     401             : 
     402             : /// Return a ConstantExpr with type DestTy for alignof on Ty, with any known
     403             : /// factors factored out. If Folded is false, return null if no factoring was
     404             : /// possible, to avoid endlessly bouncing an unfoldable expression back into the
     405             : /// top-level folder.
     406         106 : static Constant *getFoldedAlignOf(Type *Ty, Type *DestTy, bool Folded) {
     407             :   // The alignment of an array is equal to the alignment of the
     408             :   // array element. Note that this is not always true for vectors.
     409          10 :   if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
     410          10 :     Constant *C = ConstantExpr::getAlignOf(ATy->getElementType());
     411          10 :     C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
     412             :                                                       DestTy,
     413             :                                                       false),
     414             :                               C, DestTy);
     415          10 :     return C;
     416             :   }
     417             : 
     418          20 :   if (StructType *STy = dyn_cast<StructType>(Ty)) {
     419             :     // Packed structs always have an alignment of 1.
     420          20 :     if (STy->isPacked())
     421          10 :       return ConstantInt::get(DestTy, 1);
     422             : 
     423             :     // Otherwise, struct alignment is the maximum alignment of any member.
     424             :     // Without target data, we can't compare much, but we can check to see
     425             :     // if all the members have the same alignment.
     426          10 :     unsigned NumElems = STy->getNumElements();
     427             :     // An empty struct has minimal alignment.
     428          10 :     if (NumElems == 0)
     429           0 :       return ConstantInt::get(DestTy, 1);
     430             :     // Check for a struct with all members having the same alignment.
     431             :     Constant *MemberAlign =
     432          20 :       getFoldedAlignOf(STy->getElementType(0), DestTy, true);
     433          10 :     bool AllSame = true;
     434          20 :     for (unsigned i = 1; i != NumElems; ++i)
     435          20 :       if (MemberAlign != getFoldedAlignOf(STy->getElementType(i), DestTy, true)) {
     436             :         AllSame = false;
     437             :         break;
     438             :       }
     439          10 :     if (AllSame)
     440             :       return MemberAlign;
     441             :   }
     442             : 
     443             :   // Pointer alignment doesn't depend on the pointee type, so canonicalize them
     444             :   // to an arbitrary pointee.
     445          24 :   if (PointerType *PTy = dyn_cast<PointerType>(Ty))
     446          24 :     if (!PTy->getElementType()->isIntegerTy(1))
     447             :       return
     448           8 :         getFoldedAlignOf(PointerType::get(IntegerType::get(PTy->getContext(),
     449             :                                                            1),
     450             :                                           PTy->getAddressSpace()),
     451           8 :                          DestTy, true);
     452             : 
     453             :   // If there's no interesting folding happening, bail so that we don't create
     454             :   // a constant that looks like it needs folding but really doesn't.
     455          68 :   if (!Folded)
     456             :     return nullptr;
     457             : 
     458             :   // Base case: Get a regular alignof expression.
     459          28 :   Constant *C = ConstantExpr::getAlignOf(Ty);
     460          28 :   C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
     461             :                                                     DestTy, false),
     462             :                             C, DestTy);
     463          28 :   return C;
     464             : }
     465             : 
     466             : /// Return a ConstantExpr with type DestTy for offsetof on Ty and FieldNo, with
     467             : /// any known factors factored out. If Folded is false, return null if no
     468             : /// factoring was possible, to avoid endlessly bouncing an unfoldable expression
     469             : /// back into the top-level folder.
     470          35 : static Constant *getFoldedOffsetOf(Type *Ty, Constant *FieldNo, Type *DestTy,
     471             :                                    bool Folded) {
     472          10 :   if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
     473          10 :     Constant *N = ConstantExpr::getCast(CastInst::getCastOpcode(FieldNo, false,
     474             :                                                                 DestTy, false),
     475          10 :                                         FieldNo, DestTy);
     476          10 :     Constant *E = getFoldedSizeOf(ATy->getElementType(), DestTy, true);
     477          10 :     return ConstantExpr::getNUWMul(E, N);
     478             :   }
     479             : 
     480          25 :   if (StructType *STy = dyn_cast<StructType>(Ty))
     481          25 :     if (!STy->isPacked()) {
     482          25 :       unsigned NumElems = STy->getNumElements();
     483             :       // An empty struct has no members.
     484          25 :       if (NumElems == 0)
     485             :         return nullptr;
     486             :       // Check for a struct with all members having the same size.
     487             :       Constant *MemberSize =
     488          50 :         getFoldedSizeOf(STy->getElementType(0), DestTy, true);
     489          25 :       bool AllSame = true;
     490          55 :       for (unsigned i = 1; i != NumElems; ++i)
     491          45 :         if (MemberSize !=
     492          90 :             getFoldedSizeOf(STy->getElementType(i), DestTy, true)) {
     493             :           AllSame = false;
     494             :           break;
     495             :         }
     496          25 :       if (AllSame) {
     497          10 :         Constant *N = ConstantExpr::getCast(CastInst::getCastOpcode(FieldNo,
     498             :                                                                     false,
     499             :                                                                     DestTy,
     500             :                                                                     false),
     501          10 :                                             FieldNo, DestTy);
     502          10 :         return ConstantExpr::getNUWMul(MemberSize, N);
     503             :       }
     504             :     }
     505             : 
     506             :   // If there's no interesting folding happening, bail so that we don't create
     507             :   // a constant that looks like it needs folding but really doesn't.
     508          15 :   if (!Folded)
     509             :     return nullptr;
     510             : 
     511             :   // Base case: Get a regular offsetof expression.
     512           0 :   Constant *C = ConstantExpr::getOffsetOf(Ty, FieldNo);
     513           0 :   C = ConstantExpr::getCast(CastInst::getCastOpcode(C, false,
     514             :                                                     DestTy, false),
     515             :                             C, DestTy);
     516           0 :   return C;
     517             : }
     518             : 
     519     2842058 : Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
     520             :                                             Type *DestTy) {
     521     5684116 :   if (isa<UndefValue>(V)) {
     522             :     // zext(undef) = 0, because the top bits will be zero.
     523             :     // sext(undef) = 0, because the top bits will all be the same.
     524             :     // [us]itofp(undef) = 0, because the result value is bounded.
     525        8502 :     if (opc == Instruction::ZExt || opc == Instruction::SExt ||
     526        4457 :         opc == Instruction::UIToFP || opc == Instruction::SIToFP)
     527        4047 :       return Constant::getNullValue(DestTy);
     528         204 :     return UndefValue::get(DestTy);
     529             :   }
     530             : 
     531     3165097 :   if (V->isNullValue() && !DestTy->isX86_MMXTy() &&
     532             :       opc != Instruction::AddrSpaceCast)
     533      326835 :     return Constant::getNullValue(DestTy);
     534             : 
     535             :   // If the cast operand is a constant expression, there's a few things we can
     536             :   // do to try to simplify it.
     537     3250769 :   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
     538      739797 :     if (CE->isCast()) {
     539             :       // Try hard to fold cast of cast because they are often eliminable.
     540      500003 :       if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
     541      499255 :         return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
     542      713997 :     } else if (CE->getOpcode() == Instruction::GetElementPtr &&
     543             :                // Do not fold addrspacecast (gep 0, .., 0). It might make the
     544             :                // addrspacecast uncanonicalized.
     545      713921 :                opc != Instruction::AddrSpaceCast &&
     546             :                // Do not fold bitcast (gep) with inrange index, as this loses
     547             :                // information.
     548      496559 :                !cast<GEPOperator>(CE)->getInRangeIndex().hasValue()) {
     549             :       // If all of the indexes in the GEP are null values, there is no pointer
     550             :       // adjustment going on.  We might as well cast the source pointer.
     551      211901 :       bool isAllNull = true;
     552      784026 :       for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
     553      419699 :         if (!CE->getOperand(i)->isNullValue()) {
     554             :           isAllNull = false;
     555             :           break;
     556             :         }
     557      211901 :       if (isAllNull)
     558             :         // This is casting one pointer type to another, always BitCast
     559      152426 :         return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
     560             :     }
     561             :   }
     562             : 
     563             :   // If the cast operand is a constant vector, perform the cast by
     564             :   // operating on each element. In the cast of bitcasts, the element
     565             :   // count may be mismatched; don't attempt to handle that here.
     566     5578384 :   if ((isa<ConstantVector>(V) || isa<ConstantDataVector>(V)) &&
     567     1860892 :       DestTy->isVectorTy() &&
     568        1504 :       DestTy->getVectorNumElements() == V->getType()->getVectorNumElements()) {
     569        1326 :     SmallVector<Constant*, 16> res;
     570         663 :     VectorType *DestVecTy = cast<VectorType>(DestTy);
     571         663 :     Type *DstEltTy = DestVecTy->getElementType();
     572         663 :     Type *Ty = IntegerType::get(V->getContext(), 32);
     573        4215 :     for (unsigned i = 0, e = V->getType()->getVectorNumElements(); i != e; ++i) {
     574             :       Constant *C =
     575        2889 :         ConstantExpr::getExtractElement(V, ConstantInt::get(Ty, i));
     576        2889 :       res.push_back(ConstantExpr::getCast(opc, C, DstEltTy));
     577             :     }
     578         663 :     return ConstantVector::get(res);
     579             :   }
     580             : 
     581             :   // We actually have to do a cast now. Perform the cast according to the
     582             :   // opcode specified.
     583     1858628 :   switch (opc) {
     584           0 :   default:
     585           0 :     llvm_unreachable("Failed to cast constant expression");
     586        1037 :   case Instruction::FPTrunc:
     587             :   case Instruction::FPExt:
     588        2072 :     if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
     589             :       bool ignored;
     590        3105 :       APFloat Val = FPC->getValueAPF();
     591        2354 :       Val.convert(DestTy->isHalfTy() ? APFloat::IEEEhalf() :
     592         944 :                   DestTy->isFloatTy() ? APFloat::IEEEsingle() :
     593         327 :                   DestTy->isDoubleTy() ? APFloat::IEEEdouble() :
     594          48 :                   DestTy->isX86_FP80Ty() ? APFloat::x87DoubleExtended() :
     595           0 :                   DestTy->isFP128Ty() ? APFloat::IEEEquad() :
     596           0 :                   DestTy->isPPC_FP128Ty() ? APFloat::PPCDoubleDouble() :
     597             :                   APFloat::Bogus(),
     598             :                   APFloat::rmNearestTiesToEven, &ignored);
     599        1035 :       return ConstantFP::get(V->getContext(), Val);
     600             :     }
     601             :     return nullptr; // Can't fold.
     602          54 :   case Instruction::FPToUI:
     603             :   case Instruction::FPToSI:
     604         108 :     if (ConstantFP *FPC = dyn_cast<ConstantFP>(V)) {
     605          54 :       const APFloat &V = FPC->getValueAPF();
     606             :       bool ignored;
     607         108 :       uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
     608         108 :       APSInt IntVal(DestBitWidth, opc == Instruction::FPToUI);
     609          54 :       if (APFloat::opInvalidOp ==
     610          54 :           V.convertToInteger(IntVal, APFloat::rmTowardZero, &ignored)) {
     611             :         // Undefined behavior invoked - the destination type can't represent
     612             :         // the input constant.
     613           2 :         return UndefValue::get(DestTy);
     614             :       }
     615          52 :       return ConstantInt::get(FPC->getContext(), IntVal);
     616             :     }
     617             :     return nullptr; // Can't fold.
     618        9619 :   case Instruction::IntToPtr:   //always treated as unsigned
     619        9619 :     if (V->isNullValue())       // Is it an integral null value?
     620           0 :       return ConstantPointerNull::get(cast<PointerType>(DestTy));
     621             :     return nullptr;                   // Other pointer types cannot be casted
     622       11723 :   case Instruction::PtrToInt:   // always treated as unsigned
     623             :     // Is it a null pointer value?
     624       11723 :     if (V->isNullValue())
     625           0 :       return ConstantInt::get(DestTy, 0);
     626             :     // If this is a sizeof-like expression, pull out multiplications by
     627             :     // known factors to expose them to subsequent folding. If it's an
     628             :     // alignof-like expression, factor out known factors.
     629       16221 :     if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
     630        8925 :       if (CE->getOpcode() == Instruction::GetElementPtr &&
     631        4427 :           CE->getOperand(0)->isNullValue()) {
     632         449 :         GEPOperator *GEPO = cast<GEPOperator>(CE);
     633         449 :         Type *Ty = GEPO->getSourceElementType();
     634         449 :         if (CE->getNumOperands() == 2) {
     635             :           // Handle a sizeof-like expression.
     636         336 :           Constant *Idx = CE->getOperand(1);
     637        1344 :           bool isOne = isa<ConstantInt>(Idx) && cast<ConstantInt>(Idx)->isOne();
     638         336 :           if (Constant *C = getFoldedSizeOf(Ty, DestTy, !isOne)) {
     639          54 :             Idx = ConstantExpr::getCast(CastInst::getCastOpcode(Idx, true,
     640             :                                                                 DestTy, false),
     641             :                                         Idx, DestTy);
     642          54 :             return ConstantExpr::getMul(C, Idx);
     643             :           }
     644         226 :         } else if (CE->getNumOperands() == 3 &&
     645         113 :                    CE->getOperand(1)->isNullValue()) {
     646             :           // Handle an alignof-like expression.
     647         103 :           if (StructType *STy = dyn_cast<StructType>(Ty))
     648         103 :             if (!STy->isPacked()) {
     649         206 :               ConstantInt *CI = cast<ConstantInt>(CE->getOperand(2));
     650         183 :               if (CI->isOne() &&
     651         182 :                   STy->getNumElements() == 2 &&
     652         158 :                   STy->getElementType(0)->isIntegerTy(1)) {
     653         156 :                 return getFoldedAlignOf(STy->getElementType(1), DestTy, false);
     654             :               }
     655             :             }
     656             :           // Handle an offsetof-like expression.
     657          45 :           if (Ty->isStructTy() || Ty->isArrayTy()) {
     658          70 :             if (Constant *C = getFoldedOffsetOf(Ty, CE->getOperand(2),
     659          35 :                                                 DestTy, false))
     660             :               return C;
     661             :           }
     662             :         }
     663             :       }
     664             :     // Other pointer types cannot be casted
     665             :     return nullptr;
     666         766 :   case Instruction::UIToFP:
     667             :   case Instruction::SIToFP:
     668        1519 :     if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
     669         753 :       const APInt &api = CI->getValue();
     670             :       APFloat apf(DestTy->getFltSemantics(),
     671        3012 :                   APInt::getNullValue(DestTy->getPrimitiveSizeInBits()));
     672         753 :       if (APFloat::opOverflow &
     673         753 :           apf.convertFromAPInt(api, opc==Instruction::SIToFP,
     674             :                               APFloat::rmNearestTiesToEven)) {
     675             :         // Undefined behavior invoked - the destination type can't represent
     676             :         // the input constant.
     677           2 :         return UndefValue::get(DestTy);
     678             :       }
     679         751 :       return ConstantFP::get(V->getContext(), apf);
     680             :     }
     681             :     return nullptr;
     682       95960 :   case Instruction::ZExt:
     683      190598 :     if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
     684      189276 :       uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
     685       94638 :       return ConstantInt::get(V->getContext(),
     686      283914 :                               CI->getValue().zext(BitWidth));
     687             :     }
     688             :     return nullptr;
     689       66682 :   case Instruction::SExt:
     690      133345 :     if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
     691      133326 :       uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
     692       66663 :       return ConstantInt::get(V->getContext(),
     693      199989 :                               CI->getValue().sext(BitWidth));
     694             :     }
     695             :     return nullptr;
     696      179707 :   case Instruction::Trunc: {
     697      359414 :     if (V->getType()->isVectorTy())
     698             :       return nullptr;
     699             : 
     700      359408 :     uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
     701      358413 :     if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
     702      178709 :       return ConstantInt::get(V->getContext(),
     703      536127 :                               CI->getValue().trunc(DestBitWidth));
     704             :     }
     705             : 
     706             :     // The input must be a constantexpr.  See if we can simplify this based on
     707             :     // the bytes we are demanding.  Only do this if the source and dest are an
     708             :     // even multiple of a byte.
     709        1964 :     if ((DestBitWidth & 7) == 0 &&
     710        2907 :         (cast<IntegerType>(V->getType())->getBitWidth() & 7) == 0)
     711         969 :       if (Constant *Res = ExtractConstantBytes(V, 0, DestBitWidth / 8))
     712             :         return Res;
     713             : 
     714             :     return nullptr;
     715             :   }
     716     1491841 :   case Instruction::BitCast:
     717     1491841 :     return FoldBitCast(V, DestTy);
     718             :   case Instruction::AddrSpaceCast:
     719             :     return nullptr;
     720             :   }
     721             : }
     722             : 
     723        1067 : Constant *llvm::ConstantFoldSelectInstruction(Constant *Cond,
     724             :                                               Constant *V1, Constant *V2) {
     725             :   // Check for i1 and vector true/false conditions.
     726        1067 :   if (Cond->isNullValue()) return V2;
     727         519 :   if (Cond->isAllOnesValue()) return V1;
     728             : 
     729             :   // If the condition is a vector constant, fold the result elementwise.
     730         245 :   if (ConstantVector *CondV = dyn_cast<ConstantVector>(Cond)) {
     731          71 :     SmallVector<Constant*, 16> Result;
     732          70 :     Type *Ty = IntegerType::get(CondV->getContext(), 32);
     733         452 :     for (unsigned i = 0, e = V1->getType()->getVectorNumElements(); i != e;++i){
     734             :       Constant *V;
     735         313 :       Constant *V1Element = ConstantExpr::getExtractElement(V1,
     736         313 :                                                     ConstantInt::get(Ty, i));
     737         313 :       Constant *V2Element = ConstantExpr::getExtractElement(V2,
     738         313 :                                                     ConstantInt::get(Ty, i));
     739         939 :       Constant *Cond = dyn_cast<Constant>(CondV->getOperand(i));
     740         313 :       if (V1Element == V2Element) {
     741          78 :         V = V1Element;
     742         470 :       } else if (isa<UndefValue>(Cond)) {
     743          12 :         V = isa<UndefValue>(V1Element) ? V1Element : V2Element;
     744             :       } else {
     745         458 :         if (!isa<ConstantInt>(Cond)) break;
     746         228 :         V = Cond->isNullValue() ? V2Element : V1Element;
     747             :       }
     748         312 :       Result.push_back(V);
     749             :     }
     750             : 
     751             :     // If we were able to build the vector, return it.
     752         140 :     if (Result.size() == V1->getType()->getVectorNumElements())
     753          69 :       return ConstantVector::get(Result);
     754             :   }
     755             : 
     756         212 :   if (isa<UndefValue>(Cond)) {
     757           8 :     if (isa<UndefValue>(V1)) return V1;
     758           4 :     return V2;
     759             :   }
     760         204 :   if (isa<UndefValue>(V1)) return V2;
     761         204 :   if (isa<UndefValue>(V2)) return V1;
     762         101 :   if (V1 == V2) return V1;
     763             : 
     764         162 :   if (ConstantExpr *TrueVal = dyn_cast<ConstantExpr>(V1)) {
     765          61 :     if (TrueVal->getOpcode() == Instruction::Select)
     766           1 :       if (TrueVal->getOperand(0) == Cond)
     767           2 :         return ConstantExpr::getSelect(Cond, TrueVal->getOperand(1), V2);
     768             :   }
     769         119 :   if (ConstantExpr *FalseVal = dyn_cast<ConstantExpr>(V2)) {
     770          19 :     if (FalseVal->getOpcode() == Instruction::Select)
     771           0 :       if (FalseVal->getOperand(0) == Cond)
     772           0 :         return ConstantExpr::getSelect(Cond, V1, FalseVal->getOperand(2));
     773             :   }
     774             : 
     775             :   return nullptr;
     776             : }
     777             : 
     778      301642 : Constant *llvm::ConstantFoldExtractElementInstruction(Constant *Val,
     779             :                                                       Constant *Idx) {
     780      603284 :   if (isa<UndefValue>(Val))  // ee(undef, x) -> undef
     781      179782 :     return UndefValue::get(Val->getType()->getVectorElementType());
     782      211751 :   if (Val->isNullValue())  // ee(zero, x) -> zero
     783        5384 :     return Constant::getNullValue(Val->getType()->getVectorElementType());
     784             :   // ee({w,x,y,z}, undef) -> undef
     785      418118 :   if (isa<UndefValue>(Idx))
     786           2 :     return UndefValue::get(Val->getType()->getVectorElementType());
     787             : 
     788      418116 :   if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
     789             :     // ee({w,x,y,z}, wrong_value) -> undef
     790      627174 :     if (CIdx->uge(Val->getType()->getVectorNumElements()))
     791           6 :       return UndefValue::get(Val->getType()->getVectorElementType());
     792      418110 :     return Val->getAggregateElement(CIdx->getZExtValue());
     793             :   }
     794             :   return nullptr;
     795             : }
     796             : 
     797      148633 : Constant *llvm::ConstantFoldInsertElementInstruction(Constant *Val,
     798             :                                                      Constant *Elt,
     799             :                                                      Constant *Idx) {
     800      297266 :   if (isa<UndefValue>(Idx))
     801           1 :     return UndefValue::get(Val->getType());
     802             : 
     803      297264 :   ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
     804             :   if (!CIdx) return nullptr;
     805             : 
     806      297264 :   unsigned NumElts = Val->getType()->getVectorNumElements();
     807      297264 :   if (CIdx->uge(NumElts))
     808           3 :     return UndefValue::get(Val->getType());
     809             : 
     810      148629 :   SmallVector<Constant*, 16> Result;
     811      148629 :   Result.reserve(NumElts);
     812      148629 :   auto *Ty = Type::getInt32Ty(Val->getContext());
     813      148629 :   uint64_t IdxVal = CIdx->getZExtValue();
     814      557750 :   for (unsigned i = 0; i != NumElts; ++i) {
     815      557750 :     if (i == IdxVal) {
     816      148629 :       Result.push_back(Elt);
     817      148629 :       continue;
     818             :     }
     819             : 
     820      260492 :     Constant *C = ConstantExpr::getExtractElement(Val, ConstantInt::get(Ty, i));
     821      260492 :     Result.push_back(C);
     822             :   }
     823             : 
     824      148629 :   return ConstantVector::get(Result);
     825             : }
     826             : 
     827        2993 : Constant *llvm::ConstantFoldShuffleVectorInstruction(Constant *V1,
     828             :                                                      Constant *V2,
     829             :                                                      Constant *Mask) {
     830        5986 :   unsigned MaskNumElts = Mask->getType()->getVectorNumElements();
     831        5986 :   Type *EltTy = V1->getType()->getVectorElementType();
     832             : 
     833             :   // Undefined shuffle mask -> undefined value.
     834        5986 :   if (isa<UndefValue>(Mask))
     835          13 :     return UndefValue::get(VectorType::get(EltTy, MaskNumElts));
     836             : 
     837             :   // Don't break the bitcode reader hack.
     838        5960 :   if (isa<ConstantExpr>(Mask)) return nullptr;
     839             : 
     840        5960 :   unsigned SrcNumElts = V1->getType()->getVectorNumElements();
     841             : 
     842             :   // Loop over the shuffle mask, evaluating each element.
     843        2980 :   SmallVector<Constant*, 32> Result;
     844       20210 :   for (unsigned i = 0; i != MaskNumElts; ++i) {
     845       17230 :     int Elt = ShuffleVectorInst::getMaskValue(Mask, i);
     846       17427 :     if (Elt == -1) {
     847         197 :       Result.push_back(UndefValue::get(EltTy));
     848         197 :       continue;
     849             :     }
     850             :     Constant *InElt;
     851       17033 :     if (unsigned(Elt) >= SrcNumElts*2)
     852           0 :       InElt = UndefValue::get(EltTy);
     853       17033 :     else if (unsigned(Elt) >= SrcNumElts) {
     854         451 :       Type *Ty = IntegerType::get(V2->getContext(), 32);
     855         451 :       InElt =
     856         451 :         ConstantExpr::getExtractElement(V2,
     857         451 :                                         ConstantInt::get(Ty, Elt - SrcNumElts));
     858             :     } else {
     859       16582 :       Type *Ty = IntegerType::get(V1->getContext(), 32);
     860       16582 :       InElt = ConstantExpr::getExtractElement(V1, ConstantInt::get(Ty, Elt));
     861             :     }
     862       17033 :     Result.push_back(InElt);
     863             :   }
     864             : 
     865        2980 :   return ConstantVector::get(Result);
     866             : }
     867             : 
     868      305326 : Constant *llvm::ConstantFoldExtractValueInstruction(Constant *Agg,
     869             :                                                     ArrayRef<unsigned> Idxs) {
     870             :   // Base case: no indices, so return the entire value.
     871      305326 :   if (Idxs.empty())
     872             :     return Agg;
     873             : 
     874      152671 :   if (Constant *C = Agg->getAggregateElement(Idxs[0]))
     875      152667 :     return ConstantFoldExtractValueInstruction(C, Idxs.slice(1));
     876             : 
     877             :   return nullptr;
     878             : }
     879             : 
     880         590 : Constant *llvm::ConstantFoldInsertValueInstruction(Constant *Agg,
     881             :                                                    Constant *Val,
     882             :                                                    ArrayRef<unsigned> Idxs) {
     883             :   // Base case: no indices, so replace the entire value.
     884         590 :   if (Idxs.empty())
     885             :     return Val;
     886             : 
     887             :   unsigned NumElts;
     888         602 :   if (StructType *ST = dyn_cast<StructType>(Agg->getType()))
     889         245 :     NumElts = ST->getNumElements();
     890             :   else
     891         224 :     NumElts = cast<SequentialType>(Agg->getType())->getNumElements();
     892             : 
     893         357 :   SmallVector<Constant*, 32> Result;
     894        5363 :   for (unsigned i = 0; i != NumElts; ++i) {
     895        5007 :     Constant *C = Agg->getAggregateElement(i);
     896        5007 :     if (!C) return nullptr;
     897             : 
     898        5006 :     if (Idxs[0] == i)
     899         356 :       C = ConstantFoldInsertValueInstruction(C, Val, Idxs.slice(1));
     900             : 
     901        5006 :     Result.push_back(C);
     902             :   }
     903             : 
     904         600 :   if (StructType *ST = dyn_cast<StructType>(Agg->getType()))
     905         244 :     return ConstantStruct::get(ST, Result);
     906         224 :   if (ArrayType *AT = dyn_cast<ArrayType>(Agg->getType()))
     907         112 :     return ConstantArray::get(AT, Result);
     908           0 :   return ConstantVector::get(Result);
     909             : }
     910             : 
     911             : 
     912      727853 : Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
     913             :                                               Constant *C1, Constant *C2) {
     914             :   assert(Instruction::isBinaryOp(Opcode) && "Non-binary instruction detected");
     915             : 
     916             :   // Handle UndefValue up front.
     917     2183212 :   if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
     918         409 :     switch (static_cast<Instruction::BinaryOps>(Opcode)) {
     919          11 :     case Instruction::Xor:
     920          33 :       if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
     921             :         // Handle undef ^ undef -> 0 special case. This is a common
     922             :         // idiom (misuse).
     923           2 :         return Constant::getNullValue(C1->getType());
     924             :       LLVM_FALLTHROUGH;
     925             :     case Instruction::Add:
     926             :     case Instruction::Sub:
     927         113 :       return UndefValue::get(C1->getType());
     928         102 :     case Instruction::And:
     929         305 :       if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef & undef -> undef
     930             :         return C1;
     931         100 :       return Constant::getNullValue(C1->getType());   // undef & X -> 0
     932          12 :     case Instruction::Mul: {
     933             :       // undef * undef -> undef
     934          29 :       if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
     935             :         return C1;
     936             :       const APInt *CV;
     937             :       // X * undef -> undef   if X is odd
     938          26 :       if (match(C1, m_APInt(CV)) || match(C2, m_APInt(CV)))
     939          20 :         if ((*CV)[0])
     940           3 :           return UndefValue::get(C1->getType());
     941             : 
     942             :       // X * undef -> 0       otherwise
     943           7 :       return Constant::getNullValue(C1->getType());
     944             :     }
     945           8 :     case Instruction::SDiv:
     946             :     case Instruction::UDiv:
     947             :       // X / undef -> undef
     948          16 :       if (isa<UndefValue>(C2))
     949             :         return C2;
     950             :       // undef / 0 -> undef
     951             :       // undef / 1 -> undef
     952          17 :       if (match(C2, m_Zero()) || match(C2, m_One()))
     953             :         return C1;
     954             :       // undef / X -> 0       otherwise
     955           3 :       return Constant::getNullValue(C1->getType());
     956             :     case Instruction::URem:
     957             :     case Instruction::SRem:
     958             :       // X % undef -> undef
     959          22 :       if (match(C2, m_Undef()))
     960             :         return C2;
     961             :       // undef % 0 -> undef
     962          22 :       if (match(C2, m_Zero()))
     963             :         return C1;
     964             :       // undef % X -> 0       otherwise
     965          11 :       return Constant::getNullValue(C1->getType());
     966          13 :     case Instruction::Or:                          // X | undef -> -1
     967          32 :       if (isa<UndefValue>(C1) && isa<UndefValue>(C2)) // undef | undef -> undef
     968             :         return C1;
     969           8 :       return Constant::getAllOnesValue(C1->getType()); // undef | X -> ~0
     970          25 :     case Instruction::LShr:
     971             :       // X >>l undef -> undef
     972          50 :       if (isa<UndefValue>(C2))
     973             :         return C2;
     974             :       // undef >>l 0 -> undef
     975          46 :       if (match(C2, m_Zero()))
     976             :         return C1;
     977             :       // undef >>l X -> 0
     978          22 :       return Constant::getNullValue(C1->getType());
     979           7 :     case Instruction::AShr:
     980             :       // X >>a undef -> undef
     981          14 :       if (isa<UndefValue>(C2))
     982             :         return C2;
     983             :       // undef >>a 0 -> undef
     984          10 :       if (match(C2, m_Zero()))
     985             :         return C1;
     986             :       // TODO: undef >>a X -> undef if the shift is exact
     987             :       // undef >>a X -> 0
     988           4 :       return Constant::getNullValue(C1->getType());
     989          17 :     case Instruction::Shl:
     990             :       // X << undef -> undef
     991          34 :       if (isa<UndefValue>(C2))
     992             :         return C2;
     993             :       // undef << 0 -> undef
     994          30 :       if (match(C2, m_Zero()))
     995             :         return C1;
     996             :       // undef << X -> 0
     997          13 :       return Constant::getNullValue(C1->getType());
     998             :     case Instruction::FAdd:
     999             :     case Instruction::FSub:
    1000             :     case Instruction::FMul:
    1001             :     case Instruction::FDiv:
    1002             :     case Instruction::FRem:
    1003             :       // TODO: UNDEF handling for binary float instructions.
    1004             :       return nullptr;
    1005           0 :     case Instruction::BinaryOpsEnd:
    1006           0 :       llvm_unreachable("Invalid BinaryOp");
    1007             :     }
    1008             :   }
    1009             : 
    1010             :   // At this point neither constant should be an UndefValue.
    1011             :   assert(!isa<UndefValue>(C1) && !isa<UndefValue>(C2) &&
    1012             :          "Unexpected UndefValue");
    1013             : 
    1014             :   // Handle simplifications when the RHS is a constant int.
    1015     1445521 :   if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
    1016      718077 :     switch (Opcode) {
    1017      119882 :     case Instruction::Add:
    1018      119882 :       if (CI2->isZero()) return C1;                             // X + 0 == X
    1019             :       break;
    1020      457676 :     case Instruction::Sub:
    1021      457676 :       if (CI2->isZero()) return C1;                             // X - 0 == X
    1022             :       break;
    1023       16752 :     case Instruction::Mul:
    1024       16752 :       if (CI2->isZero()) return C2;                             // X * 0 == 0
    1025       16574 :       if (CI2->isOne())
    1026             :         return C1;                                              // X * 1 == X
    1027             :       break;
    1028       12819 :     case Instruction::UDiv:
    1029             :     case Instruction::SDiv:
    1030       12819 :       if (CI2->isOne())
    1031             :         return C1;                                            // X / 1 == X
    1032       11103 :       if (CI2->isZero())
    1033           5 :         return UndefValue::get(CI2->getType());               // X / 0 == undef
    1034             :       break;
    1035        1150 :     case Instruction::URem:
    1036             :     case Instruction::SRem:
    1037        1150 :       if (CI2->isOne())
    1038          14 :         return Constant::getNullValue(CI2->getType());        // X % 1 == 0
    1039        1136 :       if (CI2->isZero())
    1040           3 :         return UndefValue::get(CI2->getType());               // X % 0 == undef
    1041             :       break;
    1042       12473 :     case Instruction::And:
    1043       12473 :       if (CI2->isZero()) return C2;                           // X & 0 == 0
    1044       12430 :       if (CI2->isMinusOne())
    1045             :         return C1;                                            // X & -1 == X
    1046             : 
    1047       15380 :       if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
    1048             :         // (zext i32 to i64) & 4294967295 -> (zext i32 to i64)
    1049        2980 :         if (CE1->getOpcode() == Instruction::ZExt) {
    1050           6 :           unsigned DstWidth = CI2->getType()->getBitWidth();
    1051             :           unsigned SrcWidth =
    1052           3 :             CE1->getOperand(0)->getType()->getPrimitiveSizeInBits();
    1053           6 :           APInt PossiblySetBits(APInt::getLowBitsSet(DstWidth, SrcWidth));
    1054          18 :           if ((PossiblySetBits & CI2->getValue()) == PossiblySetBits)
    1055           0 :             return C1;
    1056             :         }
    1057             : 
    1058             :         // If and'ing the address of a global with a constant, fold it.
    1059        2980 :         if (CE1->getOpcode() == Instruction::PtrToInt &&
    1060        2948 :             isa<GlobalValue>(CE1->getOperand(0))) {
    1061         122 :           GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
    1062             : 
    1063             :           // Functions are at least 4-byte aligned.
    1064          61 :           unsigned GVAlign = GV->getAlignment();
    1065         122 :           if (isa<Function>(GV))
    1066          12 :             GVAlign = std::max(GVAlign, 4U);
    1067             : 
    1068          61 :           if (GVAlign > 1) {
    1069          72 :             unsigned DstWidth = CI2->getType()->getBitWidth();
    1070         108 :             unsigned SrcWidth = std::min(DstWidth, Log2_32(GVAlign));
    1071          51 :             APInt BitsNotSet(APInt::getLowBitsSet(DstWidth, SrcWidth));
    1072             : 
    1073             :             // If checking bits we know are clear, return zero.
    1074         216 :             if ((CI2->getValue() & BitsNotSet) == CI2->getValue())
    1075          42 :               return Constant::getNullValue(CI2->getType());
    1076             :           }
    1077             :         }
    1078             :       }
    1079             :       break;
    1080        8340 :     case Instruction::Or:
    1081        8340 :       if (CI2->isZero()) return C1;        // X | 0 == X
    1082        7768 :       if (CI2->isMinusOne())
    1083             :         return C2;                         // X | -1 == -1
    1084             :       break;
    1085       72032 :     case Instruction::Xor:
    1086       72032 :       if (CI2->isZero()) return C1;        // X ^ 0 == X
    1087             : 
    1088       72067 :       if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
    1089          65 :         switch (CE1->getOpcode()) {
    1090             :         default: break;
    1091          30 :         case Instruction::ICmp:
    1092             :         case Instruction::FCmp:
    1093             :           // cmp pred ^ true -> cmp !pred
    1094             :           assert(CI2->isOne());
    1095          30 :           CmpInst::Predicate pred = (CmpInst::Predicate)CE1->getPredicate();
    1096          30 :           pred = CmpInst::getInversePredicate(pred);
    1097          60 :           return ConstantExpr::getCompare(pred, CE1->getOperand(0),
    1098          30 :                                           CE1->getOperand(1));
    1099             :         }
    1100             :       }
    1101             :       break;
    1102         973 :     case Instruction::AShr:
    1103             :       // ashr (zext C to Ty), C2 -> lshr (zext C, CSA), C2
    1104        1000 :       if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1))
    1105          27 :         if (CE1->getOpcode() == Instruction::ZExt)  // Top bits known zero.
    1106           0 :           return ConstantExpr::getLShr(C1, C2);
    1107             :       break;
    1108             :     }
    1109       18734 :   } else if (isa<ConstantInt>(C1)) {
    1110             :     // If C1 is a ConstantInt and C2 is not, swap the operands.
    1111        1040 :     if (Instruction::isCommutative(Opcode))
    1112        1040 :       return ConstantExpr::get(Opcode, C2, C1);
    1113             :   }
    1114             : 
    1115      925913 :   if (ConstantInt *CI1 = dyn_cast<ConstantInt>(C1)) {
    1116      912674 :     if (ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
    1117      456281 :       const APInt &C1V = CI1->getValue();
    1118      456281 :       const APInt &C2V = CI2->getValue();
    1119      456281 :       switch (Opcode) {
    1120             :       default:
    1121             :         break;
    1122      116474 :       case Instruction::Add:
    1123      465896 :         return ConstantInt::get(CI1->getContext(), C1V + C2V);
    1124      211648 :       case Instruction::Sub:
    1125      846592 :         return ConstantInt::get(CI1->getContext(), C1V - C2V);
    1126       10161 :       case Instruction::Mul:
    1127       20322 :         return ConstantInt::get(CI1->getContext(), C1V * C2V);
    1128       10112 :       case Instruction::UDiv:
    1129             :         assert(!CI2->isZero() && "Div by zero handled above");
    1130       20224 :         return ConstantInt::get(CI1->getContext(), C1V.udiv(C2V));
    1131         953 :       case Instruction::SDiv:
    1132             :         assert(!CI2->isZero() && "Div by zero handled above");
    1133         953 :         if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
    1134           1 :           return UndefValue::get(CI1->getType());   // MIN_INT / -1 -> undef
    1135        1904 :         return ConstantInt::get(CI1->getContext(), C1V.sdiv(C2V));
    1136         979 :       case Instruction::URem:
    1137             :         assert(!CI2->isZero() && "Div by zero handled above");
    1138        1958 :         return ConstantInt::get(CI1->getContext(), C1V.urem(C2V));
    1139         147 :       case Instruction::SRem:
    1140             :         assert(!CI2->isZero() && "Div by zero handled above");
    1141         147 :         if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
    1142           1 :           return UndefValue::get(CI1->getType());   // MIN_INT % -1 -> undef
    1143         292 :         return ConstantInt::get(CI1->getContext(), C1V.srem(C2V));
    1144        9420 :       case Instruction::And:
    1145       37680 :         return ConstantInt::get(CI1->getContext(), C1V & C2V);
    1146        7703 :       case Instruction::Or:
    1147       30812 :         return ConstantInt::get(CI1->getContext(), C1V | C2V);
    1148       71937 :       case Instruction::Xor:
    1149      287748 :         return ConstantInt::get(CI1->getContext(), C1V ^ C2V);
    1150       12702 :       case Instruction::Shl:
    1151       12702 :         if (C2V.ult(C1V.getBitWidth()))
    1152       25366 :           return ConstantInt::get(CI1->getContext(), C1V.shl(C2V));
    1153          19 :         return UndefValue::get(C1->getType()); // too big shift is undef
    1154        3099 :       case Instruction::LShr:
    1155        3099 :         if (C2V.ult(C1V.getBitWidth()))
    1156        6158 :           return ConstantInt::get(CI1->getContext(), C1V.lshr(C2V));
    1157          20 :         return UndefValue::get(C1->getType()); // too big shift is undef
    1158         946 :       case Instruction::AShr:
    1159         946 :         if (C2V.ult(C1V.getBitWidth()))
    1160        1872 :           return ConstantInt::get(CI1->getContext(), C1V.ashr(C2V));
    1161          10 :         return UndefValue::get(C1->getType()); // too big shift is undef
    1162             :       }
    1163             :     }
    1164             : 
    1165             :     switch (Opcode) {
    1166          65 :     case Instruction::SDiv:
    1167             :     case Instruction::UDiv:
    1168             :     case Instruction::URem:
    1169             :     case Instruction::SRem:
    1170             :     case Instruction::LShr:
    1171             :     case Instruction::AShr:
    1172             :     case Instruction::Shl:
    1173          65 :       if (CI1->isZero()) return C1;
    1174             :       break;
    1175             :     default:
    1176             :       break;
    1177             :     }
    1178       13837 :   } else if (ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
    1179        1408 :     if (ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
    1180         698 :       const APFloat &C1V = CFP1->getValueAPF();
    1181         698 :       const APFloat &C2V = CFP2->getValueAPF();
    1182         698 :       APFloat C3V = C1V;  // copy for modification
    1183         698 :       switch (Opcode) {
    1184             :       default:
    1185             :         break;
    1186         213 :       case Instruction::FAdd:
    1187         213 :         (void)C3V.add(C2V, APFloat::rmNearestTiesToEven);
    1188         911 :         return ConstantFP::get(C1->getContext(), C3V);
    1189         165 :       case Instruction::FSub:
    1190         165 :         (void)C3V.subtract(C2V, APFloat::rmNearestTiesToEven);
    1191         165 :         return ConstantFP::get(C1->getContext(), C3V);
    1192         213 :       case Instruction::FMul:
    1193         213 :         (void)C3V.multiply(C2V, APFloat::rmNearestTiesToEven);
    1194         213 :         return ConstantFP::get(C1->getContext(), C3V);
    1195          46 :       case Instruction::FDiv:
    1196          46 :         (void)C3V.divide(C2V, APFloat::rmNearestTiesToEven);
    1197          46 :         return ConstantFP::get(C1->getContext(), C3V);
    1198          61 :       case Instruction::FRem:
    1199          61 :         (void)C3V.mod(C2V);
    1200          61 :         return ConstantFP::get(C1->getContext(), C3V);
    1201             :       }
    1202             :     }
    1203       14804 :   } else if (VectorType *VTy = dyn_cast<VectorType>(C1->getType())) {
    1204             :     // Perform elementwise folding.
    1205        4774 :     SmallVector<Constant*, 16> Result;
    1206        2387 :     Type *Ty = IntegerType::get(VTy->getContext(), 32);
    1207       12162 :     for (unsigned i = 0, e = VTy->getNumElements(); i != e; ++i) {
    1208        9780 :       Constant *ExtractIdx = ConstantInt::get(Ty, i);
    1209        9780 :       Constant *LHS = ConstantExpr::getExtractElement(C1, ExtractIdx);
    1210        9780 :       Constant *RHS = ConstantExpr::getExtractElement(C2, ExtractIdx);
    1211             : 
    1212             :       // If any element of a divisor vector is zero, the whole op is undef.
    1213       19560 :       if ((Opcode == Instruction::SDiv || Opcode == Instruction::UDiv ||
    1214       19607 :            Opcode == Instruction::SRem || Opcode == Instruction::URem) &&
    1215          47 :           RHS->isNullValue())
    1216           5 :         return UndefValue::get(VTy);
    1217             : 
    1218        9775 :       Result.push_back(ConstantExpr::get(Opcode, LHS, RHS));
    1219             :     }
    1220             : 
    1221        2382 :     return ConstantVector::get(Result);
    1222             :   }
    1223             : 
    1224       20175 :   if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
    1225             :     // There are many possible foldings we could do here.  We should probably
    1226             :     // at least fold add of a pointer with an integer into the appropriate
    1227             :     // getelementptr.  This will improve alias analysis a bit.
    1228             : 
    1229             :     // Given ((a + b) + c), if (b + c) folds to something interesting, return
    1230             :     // (a + (b + c)).
    1231        8571 :     if (Instruction::isAssociative(Opcode) && CE1->getOpcode() == Opcode) {
    1232         124 :       Constant *T = ConstantExpr::get(Opcode, CE1->getOperand(1), C2);
    1233         154 :       if (!isa<ConstantExpr>(T) || cast<ConstantExpr>(T)->getOpcode() != Opcode)
    1234          94 :         return ConstantExpr::get(Opcode, CE1->getOperand(0), T);
    1235             :     }
    1236         230 :   } else if (isa<ConstantExpr>(C2)) {
    1237             :     // If C2 is a constant expr and C1 isn't, flop them around and fold the
    1238             :     // other way if possible.
    1239           1 :     if (Instruction::isCommutative(Opcode))
    1240           1 :       return ConstantFoldBinaryInstruction(Opcode, C2, C1);
    1241             :   }
    1242             : 
    1243             :   // i1 can be simplified in many cases.
    1244       10097 :   if (C1->getType()->isIntegerTy(1)) {
    1245         700 :     switch (Opcode) {
    1246           2 :     case Instruction::Add:
    1247             :     case Instruction::Sub:
    1248           2 :       return ConstantExpr::getXor(C1, C2);
    1249           1 :     case Instruction::Mul:
    1250           1 :       return ConstantExpr::getAnd(C1, C2);
    1251             :     case Instruction::Shl:
    1252             :     case Instruction::LShr:
    1253             :     case Instruction::AShr:
    1254             :       // We can assume that C2 == 0.  If it were one the result would be
    1255             :       // undefined because the shift value is as large as the bitwidth.
    1256             :       return C1;
    1257             :     case Instruction::SDiv:
    1258             :     case Instruction::UDiv:
    1259             :       // We can assume that C2 == 1.  If it were zero the result would be
    1260             :       // undefined through division by zero.
    1261             :       return C1;
    1262           2 :     case Instruction::URem:
    1263             :     case Instruction::SRem:
    1264             :       // We can assume that C2 == 1.  If it were zero the result would be
    1265             :       // undefined through division by zero.
    1266           2 :       return ConstantInt::getFalse(C1->getContext());
    1267             :     default:
    1268             :       break;
    1269             :     }
    1270             :   }
    1271             : 
    1272             :   // We don't know how to fold this.
    1273       10090 :   return nullptr;
    1274             : }
    1275             : 
    1276             : /// This type is zero-sized if it's an array or structure of zero-sized types.
    1277             : /// The only leaf zero-sized type is an empty structure.
    1278          31 : static bool isMaybeZeroSizedType(Type *Ty) {
    1279          10 :   if (StructType *STy = dyn_cast<StructType>(Ty)) {
    1280          10 :     if (STy->isOpaque()) return true;  // Can't say.
    1281             : 
    1282             :     // If all of elements have zero size, this does too.
    1283          10 :     for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
    1284          20 :       if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
    1285             :     return true;
    1286             : 
    1287          18 :   } else if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
    1288          18 :     return isMaybeZeroSizedType(ATy->getElementType());
    1289             :   }
    1290             :   return false;
    1291             : }
    1292             : 
    1293             : /// Compare the two constants as though they were getelementptr indices.
    1294             : /// This allows coercion of the types to be the same thing.
    1295             : ///
    1296             : /// If the two constants are the "same" (after coercion), return 0.  If the
    1297             : /// first is less than the second, return -1, if the second is less than the
    1298             : /// first, return 1.  If the constants are not integral, return -2.
    1299             : ///
    1300          28 : static int IdxCompare(Constant *C1, Constant *C2, Type *ElTy) {
    1301          28 :   if (C1 == C2) return 0;
    1302             : 
    1303             :   // Ok, we found a different index.  If they are not ConstantInt, we can't do
    1304             :   // anything with them.
    1305          65 :   if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
    1306             :     return -2; // don't know!
    1307             : 
    1308             :   // We cannot compare the indices if they don't fit in an int64_t.
    1309         105 :   if (cast<ConstantInt>(C1)->getValue().getActiveBits() > 64 ||
    1310          84 :       cast<ConstantInt>(C2)->getValue().getActiveBits() > 64)
    1311             :     return -2; // don't know!
    1312             : 
    1313             :   // Ok, we have two differing integer indices.  Sign extend them to be the same
    1314             :   // type.
    1315          63 :   int64_t C1Val = cast<ConstantInt>(C1)->getSExtValue();
    1316          63 :   int64_t C2Val = cast<ConstantInt>(C2)->getSExtValue();
    1317             : 
    1318          21 :   if (C1Val == C2Val) return 0;  // They are equal
    1319             : 
    1320             :   // If the type being indexed over is really just a zero sized type, there is
    1321             :   // no pointer difference being made here.
    1322          21 :   if (isMaybeZeroSizedType(ElTy))
    1323             :     return -2; // dunno.
    1324             : 
    1325             :   // If they are really different, now that they are the same type, then we
    1326             :   // found a difference!
    1327          21 :   if (C1Val < C2Val)
    1328             :     return -1;
    1329             :   else
    1330           0 :     return 1;
    1331             : }
    1332             : 
    1333             : /// This function determines if there is anything we can decide about the two
    1334             : /// constants provided. This doesn't need to handle simple things like
    1335             : /// ConstantFP comparisons, but should instead handle ConstantExprs.
    1336             : /// If we can determine that the two constants have a particular relation to
    1337             : /// each other, we should return the corresponding FCmpInst predicate,
    1338             : /// otherwise return FCmpInst::BAD_FCMP_PREDICATE. This is used below in
    1339             : /// ConstantFoldCompareInstruction.
    1340             : ///
    1341             : /// To simplify this code we canonicalize the relation so that the first
    1342             : /// operand is always the most "complex" of the two.  We consider ConstantFP
    1343             : /// to be the simplest, and ConstantExprs to be the most complex.
    1344          14 : static FCmpInst::Predicate evaluateFCmpRelation(Constant *V1, Constant *V2) {
    1345             :   assert(V1->getType() == V2->getType() &&
    1346             :          "Cannot compare values of different types!");
    1347             : 
    1348             :   // Handle degenerate case quickly
    1349          14 :   if (V1 == V2) return FCmpInst::FCMP_OEQ;
    1350             : 
    1351          28 :   if (!isa<ConstantExpr>(V1)) {
    1352           0 :     if (!isa<ConstantExpr>(V2)) {
    1353             :       // Simple case, use the standard constant folder.
    1354           0 :       ConstantInt *R = nullptr;
    1355           0 :       R = dyn_cast<ConstantInt>(
    1356             :                       ConstantExpr::getFCmp(FCmpInst::FCMP_OEQ, V1, V2));
    1357           0 :       if (R && !R->isZero())
    1358             :         return FCmpInst::FCMP_OEQ;
    1359           0 :       R = dyn_cast<ConstantInt>(
    1360             :                       ConstantExpr::getFCmp(FCmpInst::FCMP_OLT, V1, V2));
    1361           0 :       if (R && !R->isZero())
    1362             :         return FCmpInst::FCMP_OLT;
    1363           0 :       R = dyn_cast<ConstantInt>(
    1364             :                       ConstantExpr::getFCmp(FCmpInst::FCMP_OGT, V1, V2));
    1365           0 :       if (R && !R->isZero())
    1366             :         return FCmpInst::FCMP_OGT;
    1367             : 
    1368             :       // Nothing more we can do
    1369             :       return FCmpInst::BAD_FCMP_PREDICATE;
    1370             :     }
    1371             : 
    1372             :     // If the first operand is simple and second is ConstantExpr, swap operands.
    1373           0 :     FCmpInst::Predicate SwappedRelation = evaluateFCmpRelation(V2, V1);
    1374           0 :     if (SwappedRelation != FCmpInst::BAD_FCMP_PREDICATE)
    1375           0 :       return FCmpInst::getSwappedPredicate(SwappedRelation);
    1376             :   } else {
    1377             :     // Ok, the LHS is known to be a constantexpr.  The RHS can be any of a
    1378             :     // constantexpr or a simple constant.
    1379             :     ConstantExpr *CE1 = cast<ConstantExpr>(V1);
    1380             :     switch (CE1->getOpcode()) {
    1381             :     case Instruction::FPTrunc:
    1382             :     case Instruction::FPExt:
    1383             :     case Instruction::UIToFP:
    1384             :     case Instruction::SIToFP:
    1385             :       // We might be able to do something with these but we don't right now.
    1386             :       break;
    1387             :     default:
    1388             :       break;
    1389             :     }
    1390             :   }
    1391             :   // There are MANY other foldings that we could perform here.  They will
    1392             :   // probably be added on demand, as they seem needed.
    1393             :   return FCmpInst::BAD_FCMP_PREDICATE;
    1394             : }
    1395             : 
    1396         108 : static ICmpInst::Predicate areGlobalsPotentiallyEqual(const GlobalValue *GV1,
    1397             :                                                       const GlobalValue *GV2) {
    1398         159 :   auto isGlobalUnsafeForEquality = [](const GlobalValue *GV) {
    1399         277 :     if (GV->hasExternalWeakLinkage() || GV->hasWeakAnyLinkage())
    1400             :       return true;
    1401         105 :     if (const auto *GVar = dyn_cast<GlobalVariable>(GV)) {
    1402         105 :       Type *Ty = GVar->getValueType();
    1403             :       // A global with opaque type might end up being zero sized.
    1404         105 :       if (!Ty->isSized())
    1405             :         return true;
    1406             :       // A global with an empty type might lie at the address of any other
    1407             :       // global.
    1408         105 :       if (Ty->isEmptyTy())
    1409             :         return true;
    1410             :     }
    1411             :     return false;
    1412             :   };
    1413             :   // Don't try to decide equality of aliases.
    1414         324 :   if (!isa<GlobalAlias>(GV1) && !isa<GlobalAlias>(GV2))
    1415         108 :     if (!isGlobalUnsafeForEquality(GV1) && !isGlobalUnsafeForEquality(GV2))
    1416             :       return ICmpInst::ICMP_NE;
    1417             :   return ICmpInst::BAD_ICMP_PREDICATE;
    1418             : }
    1419             : 
    1420             : /// This function determines if there is anything we can decide about the two
    1421             : /// constants provided. This doesn't need to handle simple things like integer
    1422             : /// comparisons, but should instead handle ConstantExprs and GlobalValues.
    1423             : /// If we can determine that the two constants have a particular relation to
    1424             : /// each other, we should return the corresponding ICmp predicate, otherwise
    1425             : /// return ICmpInst::BAD_ICMP_PREDICATE.
    1426             : ///
    1427             : /// To simplify this code we canonicalize the relation so that the first
    1428             : /// operand is always the most "complex" of the two.  We consider simple
    1429             : /// constants (like ConstantInt) to be the simplest, followed by
    1430             : /// GlobalValues, followed by ConstantExpr's (the most complex).
    1431             : ///
    1432       17418 : static ICmpInst::Predicate evaluateICmpRelation(Constant *V1, Constant *V2,
    1433             :                                                 bool isSigned) {
    1434             :   assert(V1->getType() == V2->getType() &&
    1435             :          "Cannot compare different types of values!");
    1436       17418 :   if (V1 == V2) return ICmpInst::ICMP_EQ;
    1437             : 
    1438       12632 :   if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1) &&
    1439          14 :       !isa<BlockAddress>(V1)) {
    1440          40 :     if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2) &&
    1441           1 :         !isa<BlockAddress>(V2)) {
    1442             :       // We distilled this down to a simple case, use the standard constant
    1443             :       // folder.
    1444           1 :       ConstantInt *R = nullptr;
    1445           1 :       ICmpInst::Predicate pred = ICmpInst::ICMP_EQ;
    1446           1 :       R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
    1447           0 :       if (R && !R->isZero())
    1448             :         return pred;
    1449           1 :       pred = isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
    1450           1 :       R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
    1451           0 :       if (R && !R->isZero())
    1452             :         return pred;
    1453           1 :       pred = isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
    1454           1 :       R = dyn_cast<ConstantInt>(ConstantExpr::getICmp(pred, V1, V2));
    1455           0 :       if (R && !R->isZero())
    1456             :         return pred;
    1457             : 
    1458             :       // If we couldn't figure it out, bail.
    1459             :       return ICmpInst::BAD_ICMP_PREDICATE;
    1460             :     }
    1461             : 
    1462             :     // If the first operand is simple, swap operands.
    1463             :     ICmpInst::Predicate SwappedRelation =
    1464          12 :       evaluateICmpRelation(V2, V1, isSigned);
    1465          12 :     if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
    1466           0 :       return ICmpInst::getSwappedPredicate(SwappedRelation);
    1467             : 
    1468        6586 :   } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1)) {
    1469         580 :     if (isa<ConstantExpr>(V2)) {  // Swap as necessary.
    1470             :       ICmpInst::Predicate SwappedRelation =
    1471           5 :         evaluateICmpRelation(V2, V1, isSigned);
    1472           5 :       if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
    1473           4 :         return ICmpInst::getSwappedPredicate(SwappedRelation);
    1474             :       return ICmpInst::BAD_ICMP_PREDICATE;
    1475             :     }
    1476             : 
    1477             :     // Now we know that the RHS is a GlobalValue, BlockAddress or simple
    1478             :     // constant (which, since the types must match, means that it's a
    1479             :     // ConstantPointerNull).
    1480         380 :     if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
    1481          95 :       return areGlobalsPotentiallyEqual(GV, GV2);
    1482         380 :     } else if (isa<BlockAddress>(V2)) {
    1483             :       return ICmpInst::ICMP_NE; // Globals never equal labels.
    1484             :     } else {
    1485             :       assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
    1486             :       // GlobalVals can never be null unless they have external weak linkage.
    1487             :       // We don't try to evaluate aliases here.
    1488         397 :       if (!GV->hasExternalWeakLinkage() && !isa<GlobalAlias>(GV))
    1489             :         return ICmpInst::ICMP_NE;
    1490             :     }
    1491        6007 :   } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(V1)) {
    1492           2 :     if (isa<ConstantExpr>(V2)) {  // Swap as necessary.
    1493             :       ICmpInst::Predicate SwappedRelation =
    1494           0 :         evaluateICmpRelation(V2, V1, isSigned);
    1495           0 :       if (SwappedRelation != ICmpInst::BAD_ICMP_PREDICATE)
    1496           0 :         return ICmpInst::getSwappedPredicate(SwappedRelation);
    1497             :       return ICmpInst::BAD_ICMP_PREDICATE;
    1498             :     }
    1499             : 
    1500             :     // Now we know that the RHS is a GlobalValue, BlockAddress or simple
    1501             :     // constant (which, since the types must match, means that it is a
    1502             :     // ConstantPointerNull).
    1503           1 :     if (const BlockAddress *BA2 = dyn_cast<BlockAddress>(V2)) {
    1504             :       // Block address in another function can't equal this one, but block
    1505             :       // addresses in the current function might be the same if blocks are
    1506             :       // empty.
    1507           0 :       if (BA2->getFunction() != BA->getFunction())
    1508             :         return ICmpInst::ICMP_NE;
    1509             :     } else {
    1510             :       // Block addresses aren't null, don't equal the address of globals.
    1511             :       assert((isa<ConstantPointerNull>(V2) || isa<GlobalValue>(V2)) &&
    1512             :              "Canonicalization guarantee!");
    1513             :       return ICmpInst::ICMP_NE;
    1514             :     }
    1515             :   } else {
    1516             :     // Ok, the LHS is known to be a constantexpr.  The RHS can be any of a
    1517             :     // constantexpr, a global, block address, or a simple constant.
    1518       12010 :     ConstantExpr *CE1 = cast<ConstantExpr>(V1);
    1519        6005 :     Constant *CE1Op0 = CE1->getOperand(0);
    1520             : 
    1521        6005 :     switch (CE1->getOpcode()) {
    1522             :     case Instruction::Trunc:
    1523             :     case Instruction::FPTrunc:
    1524             :     case Instruction::FPExt:
    1525             :     case Instruction::FPToUI:
    1526             :     case Instruction::FPToSI:
    1527             :       break; // We can't evaluate floating point casts or truncations.
    1528             : 
    1529        1090 :     case Instruction::UIToFP:
    1530             :     case Instruction::SIToFP:
    1531             :     case Instruction::BitCast:
    1532             :     case Instruction::ZExt:
    1533             :     case Instruction::SExt:
    1534             :       // We can't evaluate floating point casts or truncations.
    1535        2175 :       if (CE1Op0->getType()->isFloatingPointTy())
    1536             :         break;
    1537             : 
    1538             :       // If the cast is not actually changing bits, and the second operand is a
    1539             :       // null pointer, do the comparison with the pre-casted value.
    1540        2127 :       if (V2->isNullValue() &&
    1541        3538 :           (CE1->getType()->isPointerTy() || CE1->getType()->isIntegerTy())) {
    1542        1042 :         if (CE1->getOpcode() == Instruction::ZExt) isSigned = false;
    1543        1042 :         if (CE1->getOpcode() == Instruction::SExt) isSigned = true;
    1544        1042 :         return evaluateICmpRelation(CE1Op0,
    1545             :                                     Constant::getNullValue(CE1Op0->getType()),
    1546        1042 :                                     isSigned);
    1547             :       }
    1548             :       break;
    1549             : 
    1550        2913 :     case Instruction::GetElementPtr: {
    1551        2913 :       GEPOperator *CE1GEP = cast<GEPOperator>(CE1);
    1552             :       // Ok, since this is a getelementptr, we know that the constant has a
    1553             :       // pointer type.  Check the various cases.
    1554        5826 :       if (isa<ConstantPointerNull>(V2)) {
    1555             :         // If we are comparing a GEP to a null pointer, check to see if the base
    1556             :         // of the GEP equals the null pointer.
    1557        5263 :         if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
    1558        2540 :           if (GV->hasExternalWeakLinkage())
    1559             :             // Weak linkage GVals could be zero or not. We're comparing that
    1560             :             // to null pointer so its greater-or-equal
    1561           0 :             return isSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE;
    1562             :           else
    1563             :             // If its not weak linkage, the GVal must have a non-zero address
    1564             :             // so the result is greater-than
    1565        2540 :             return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
    1566         366 :         } else if (isa<ConstantPointerNull>(CE1Op0)) {
    1567             :           // If we are indexing from a null pointer, check to see if we have any
    1568             :           // non-zero indices.
    1569           0 :           for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
    1570           0 :             if (!CE1->getOperand(i)->isNullValue())
    1571             :               // Offsetting from null, must not be equal.
    1572           0 :               return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
    1573             :           // Only zero indexes from null, must still be zero.
    1574             :           return ICmpInst::ICMP_EQ;
    1575             :         }
    1576             :         // Otherwise, we can't really say if the first operand is null or not.
    1577         322 :       } else if (const GlobalValue *GV2 = dyn_cast<GlobalValue>(V2)) {
    1578         264 :         if (isa<ConstantPointerNull>(CE1Op0)) {
    1579           0 :           if (GV2->hasExternalWeakLinkage())
    1580             :             // Weak linkage GVals could be zero or not. We're comparing it to
    1581             :             // a null pointer, so its less-or-equal
    1582           0 :             return isSigned ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE;
    1583             :           else
    1584             :             // If its not weak linkage, the GVal must have a non-zero address
    1585             :             // so the result is less-than
    1586           0 :             return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
    1587         264 :         } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
    1588         132 :           if (GV == GV2) {
    1589             :             // If this is a getelementptr of the same global, then it must be
    1590             :             // different.  Because the types must match, the getelementptr could
    1591             :             // only have at most one index, and because we fold getelementptr's
    1592             :             // with a single zero index, it must be nonzero.
    1593             :             assert(CE1->getNumOperands() == 2 &&
    1594             :                    !CE1->getOperand(1)->isNullValue() &&
    1595             :                    "Surprising getelementptr!");
    1596           5 :             return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
    1597             :           } else {
    1598         127 :             if (CE1GEP->hasAllZeroIndices())
    1599           9 :               return areGlobalsPotentiallyEqual(GV, GV2);
    1600             :             return ICmpInst::BAD_ICMP_PREDICATE;
    1601             :           }
    1602             :         }
    1603             :       } else {
    1604         116 :         ConstantExpr *CE2 = cast<ConstantExpr>(V2);
    1605          58 :         Constant *CE2Op0 = CE2->getOperand(0);
    1606             : 
    1607             :         // There are MANY other foldings that we could perform here.  They will
    1608             :         // probably be added on demand, as they seem needed.
    1609          58 :         switch (CE2->getOpcode()) {
    1610             :         default: break;
    1611          55 :         case Instruction::GetElementPtr:
    1612             :           // By far the most common case to handle is when the base pointers are
    1613             :           // obviously to the same global.
    1614         108 :           if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
    1615             :             // Don't know relative ordering, but check for inequality.
    1616          48 :             if (CE1Op0 != CE2Op0) {
    1617          26 :               GEPOperator *CE2GEP = cast<GEPOperator>(CE2);
    1618          26 :               if (CE1GEP->hasAllZeroIndices() && CE2GEP->hasAllZeroIndices())
    1619          12 :                 return areGlobalsPotentiallyEqual(cast<GlobalValue>(CE1Op0),
    1620           8 :                                                   cast<GlobalValue>(CE2Op0));
    1621             :               return ICmpInst::BAD_ICMP_PREDICATE;
    1622             :             }
    1623             :             // Ok, we know that both getelementptr instructions are based on the
    1624             :             // same global.  From this, we can precisely determine the relative
    1625             :             // ordering of the resultant pointers.
    1626          22 :             unsigned i = 1;
    1627             : 
    1628             :             // The logic below assumes that the result of the comparison
    1629             :             // can be determined by finding the first index that differs.
    1630             :             // This doesn't work if there is over-indexing in any
    1631             :             // subsequent indices, so check for that case first.
    1632          44 :             if (!CE1->isGEPWithNoNotionalOverIndexing() ||
    1633          22 :                 !CE2->isGEPWithNoNotionalOverIndexing())
    1634             :                return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
    1635             : 
    1636             :             // Compare all of the operands the GEP's have in common.
    1637          22 :             gep_type_iterator GTI = gep_type_begin(CE1);
    1638          62 :             for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
    1639             :                  ++i, ++GTI)
    1640          84 :               switch (IdxCompare(CE1->getOperand(i),
    1641             :                                  CE2->getOperand(i), GTI.getIndexedType())) {
    1642          21 :               case -1: return isSigned ? ICmpInst::ICMP_SLT:ICmpInst::ICMP_ULT;
    1643           0 :               case 1:  return isSigned ? ICmpInst::ICMP_SGT:ICmpInst::ICMP_UGT;
    1644             :               case -2: return ICmpInst::BAD_ICMP_PREDICATE;
    1645             :               }
    1646             : 
    1647             :             // Ok, we ran out of things they have in common.  If any leftovers
    1648             :             // are non-zero then we have a difference, otherwise we are equal.
    1649           0 :             for (; i < CE1->getNumOperands(); ++i)
    1650           0 :               if (!CE1->getOperand(i)->isNullValue()) {
    1651           0 :                 if (isa<ConstantInt>(CE1->getOperand(i)))
    1652           0 :                   return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
    1653             :                 else
    1654             :                   return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
    1655             :               }
    1656             : 
    1657           0 :             for (; i < CE2->getNumOperands(); ++i)
    1658           0 :               if (!CE2->getOperand(i)->isNullValue()) {
    1659           0 :                 if (isa<ConstantInt>(CE2->getOperand(i)))
    1660           0 :                   return isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT;
    1661             :                 else
    1662             :                   return ICmpInst::BAD_ICMP_PREDICATE; // Might be equal.
    1663             :               }
    1664             :             return ICmpInst::ICMP_EQ;
    1665             :           }
    1666             :         }
    1667             :       }
    1668             :     }
    1669             :     default:
    1670             :       break;
    1671             :     }
    1672             :   }
    1673             : 
    1674             :   return ICmpInst::BAD_ICMP_PREDICATE;
    1675             : }
    1676             : 
    1677       89005 : Constant *llvm::ConstantFoldCompareInstruction(unsigned short pred,
    1678             :                                                Constant *C1, Constant *C2) {
    1679             :   Type *ResultTy;
    1680       89089 :   if (VectorType *VT = dyn_cast<VectorType>(C1->getType()))
    1681          84 :     ResultTy = VectorType::get(Type::getInt1Ty(C1->getContext()),
    1682          84 :                                VT->getNumElements());
    1683             :   else
    1684       88921 :     ResultTy = Type::getInt1Ty(C1->getContext());
    1685             : 
    1686             :   // Fold FCMP_FALSE/FCMP_TRUE unconditionally.
    1687       89005 :   if (pred == FCmpInst::FCMP_FALSE)
    1688           0 :     return Constant::getNullValue(ResultTy);
    1689             : 
    1690       89005 :   if (pred == FCmpInst::FCMP_TRUE)
    1691           0 :     return Constant::getAllOnesValue(ResultTy);
    1692             : 
    1693             :   // Handle some degenerate cases first
    1694      266870 :   if (isa<UndefValue>(C1) || isa<UndefValue>(C2)) {
    1695         166 :     CmpInst::Predicate Predicate = CmpInst::Predicate(pred);
    1696         166 :     bool isIntegerPredicate = ICmpInst::isIntPredicate(Predicate);
    1697             :     // For EQ and NE, we can always pick a value for the undef to make the
    1698             :     // predicate pass or fail, so we can return undef.
    1699             :     // Also, if both operands are undef, we can return undef for int comparison.
    1700         166 :     if (ICmpInst::isEquality(Predicate) || (isIntegerPredicate && C1 == C2))
    1701          89 :       return UndefValue::get(ResultTy);
    1702             : 
    1703             :     // Otherwise, for integer compare, pick the same value as the non-undef
    1704             :     // operand, and fold it to true or false.
    1705          77 :     if (isIntegerPredicate)
    1706          54 :       return ConstantInt::get(ResultTy, CmpInst::isTrueWhenEqual(Predicate));
    1707             : 
    1708             :     // Choosing NaN for the undef will always make unordered comparison succeed
    1709             :     // and ordered comparison fails.
    1710          23 :     return ConstantInt::get(ResultTy, CmpInst::isUnordered(Predicate));
    1711             :   }
    1712             : 
    1713             :   // icmp eq/ne(null,GV) -> false/true
    1714       88839 :   if (C1->isNullValue()) {
    1715       34667 :     if (const GlobalValue *GV = dyn_cast<GlobalValue>(C2))
    1716             :       // Don't try to evaluate aliases.  External weak GV can be null.
    1717           0 :       if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
    1718           0 :         if (pred == ICmpInst::ICMP_EQ)
    1719           0 :           return ConstantInt::getFalse(C1->getContext());
    1720           0 :         else if (pred == ICmpInst::ICMP_NE)
    1721           0 :           return ConstantInt::getTrue(C1->getContext());
    1722             :       }
    1723             :   // icmp eq/ne(GV,null) -> false/true
    1724       54172 :   } else if (C2->isNullValue()) {
    1725       19241 :     if (const GlobalValue *GV = dyn_cast<GlobalValue>(C1))
    1726             :       // Don't try to evaluate aliases.  External weak GV can be null.
    1727         252 :       if (!isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage()) {
    1728          31 :         if (pred == ICmpInst::ICMP_EQ)
    1729          12 :           return ConstantInt::getFalse(C1->getContext());
    1730          19 :         else if (pred == ICmpInst::ICMP_NE)
    1731          15 :           return ConstantInt::getTrue(C1->getContext());
    1732             :       }
    1733             :   }
    1734             : 
    1735             :   // If the comparison is a comparison between two i1's, simplify it.
    1736       88812 :   if (C1->getType()->isIntegerTy(1)) {
    1737          99 :     switch(pred) {
    1738          42 :     case ICmpInst::ICMP_EQ:
    1739          84 :       if (isa<ConstantInt>(C2))
    1740          42 :         return ConstantExpr::getXor(C1, ConstantExpr::getNot(C2));
    1741           0 :       return ConstantExpr::getXor(ConstantExpr::getNot(C1), C2);
    1742          13 :     case ICmpInst::ICMP_NE:
    1743          13 :       return ConstantExpr::getXor(C1, C2);
    1744             :     default:
    1745             :       break;
    1746             :     }
    1747             :   }
    1748             : 
    1749      249560 :   if (isa<ConstantInt>(C1) && isa<ConstantInt>(C2)) {
    1750      216108 :     const APInt &V1 = cast<ConstantInt>(C1)->getValue();
    1751      216108 :     const APInt &V2 = cast<ConstantInt>(C2)->getValue();
    1752       72036 :     switch (pred) {
    1753           0 :     default: llvm_unreachable("Invalid ICmp Predicate");
    1754       46954 :     case ICmpInst::ICMP_EQ:  return ConstantInt::get(ResultTy, V1 == V2);
    1755        8866 :     case ICmpInst::ICMP_NE:  return ConstantInt::get(ResultTy, V1 != V2);
    1756        6096 :     case ICmpInst::ICMP_SLT: return ConstantInt::get(ResultTy, V1.slt(V2));
    1757       15660 :     case ICmpInst::ICMP_SGT: return ConstantInt::get(ResultTy, V1.sgt(V2));
    1758        4572 :     case ICmpInst::ICMP_SLE: return ConstantInt::get(ResultTy, V1.sle(V2));
    1759         980 :     case ICmpInst::ICMP_SGE: return ConstantInt::get(ResultTy, V1.sge(V2));
    1760       46518 :     case ICmpInst::ICMP_ULT: return ConstantInt::get(ResultTy, V1.ult(V2));
    1761        9670 :     case ICmpInst::ICMP_UGT: return ConstantInt::get(ResultTy, V1.ugt(V2));
    1762        4732 :     case ICmpInst::ICMP_ULE: return ConstantInt::get(ResultTy, V1.ule(V2));
    1763          24 :     case ICmpInst::ICMP_UGE: return ConstantInt::get(ResultTy, V1.uge(V2));
    1764             :     }
    1765       33988 :   } else if (isa<ConstantFP>(C1) && isa<ConstantFP>(C2)) {
    1766         819 :     const APFloat &C1V = cast<ConstantFP>(C1)->getValueAPF();
    1767         819 :     const APFloat &C2V = cast<ConstantFP>(C2)->getValueAPF();
    1768         273 :     APFloat::cmpResult R = C1V.compare(C2V);
    1769         273 :     switch (pred) {
    1770           0 :     default: llvm_unreachable("Invalid FCmp Predicate");
    1771           0 :     case FCmpInst::FCMP_FALSE: return Constant::getNullValue(ResultTy);
    1772           0 :     case FCmpInst::FCMP_TRUE:  return Constant::getAllOnesValue(ResultTy);
    1773           9 :     case FCmpInst::FCMP_UNO:
    1774           9 :       return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered);
    1775           1 :     case FCmpInst::FCMP_ORD:
    1776           1 :       return ConstantInt::get(ResultTy, R!=APFloat::cmpUnordered);
    1777           7 :     case FCmpInst::FCMP_UEQ:
    1778          14 :       return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
    1779          14 :                                         R==APFloat::cmpEqual);
    1780          44 :     case FCmpInst::FCMP_OEQ:
    1781          44 :       return ConstantInt::get(ResultTy, R==APFloat::cmpEqual);
    1782          86 :     case FCmpInst::FCMP_UNE:
    1783          86 :       return ConstantInt::get(ResultTy, R!=APFloat::cmpEqual);
    1784           2 :     case FCmpInst::FCMP_ONE:
    1785           4 :       return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
    1786           4 :                                         R==APFloat::cmpGreaterThan);
    1787          10 :     case FCmpInst::FCMP_ULT:
    1788          20 :       return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
    1789          20 :                                         R==APFloat::cmpLessThan);
    1790          22 :     case FCmpInst::FCMP_OLT:
    1791          22 :       return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan);
    1792           4 :     case FCmpInst::FCMP_UGT:
    1793           4 :       return ConstantInt::get(ResultTy, R==APFloat::cmpUnordered ||
    1794           4 :                                         R==APFloat::cmpGreaterThan);
    1795          19 :     case FCmpInst::FCMP_OGT:
    1796          19 :       return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan);
    1797           0 :     case FCmpInst::FCMP_ULE:
    1798           0 :       return ConstantInt::get(ResultTy, R!=APFloat::cmpGreaterThan);
    1799          12 :     case FCmpInst::FCMP_OLE:
    1800          12 :       return ConstantInt::get(ResultTy, R==APFloat::cmpLessThan ||
    1801          12 :                                         R==APFloat::cmpEqual);
    1802          39 :     case FCmpInst::FCMP_UGE:
    1803          39 :       return ConstantInt::get(ResultTy, R!=APFloat::cmpLessThan);
    1804          18 :     case FCmpInst::FCMP_OGE:
    1805          18 :       return ConstantInt::get(ResultTy, R==APFloat::cmpGreaterThan ||
    1806          18 :                                         R==APFloat::cmpEqual);
    1807             :     }
    1808       32896 :   } else if (C1->getType()->isVectorTy()) {
    1809             :     // If we can constant fold the comparison of each element, constant fold
    1810             :     // the whole vector comparison.
    1811         150 :     SmallVector<Constant*, 4> ResElts;
    1812          75 :     Type *Ty = IntegerType::get(C1->getContext(), 32);
    1813             :     // Compare the elements, producing an i1 result or constant expr.
    1814         514 :     for (unsigned i = 0, e = C1->getType()->getVectorNumElements(); i != e;++i){
    1815             :       Constant *C1E =
    1816         364 :         ConstantExpr::getExtractElement(C1, ConstantInt::get(Ty, i));
    1817             :       Constant *C2E =
    1818         364 :         ConstantExpr::getExtractElement(C2, ConstantInt::get(Ty, i));
    1819             : 
    1820         364 :       ResElts.push_back(ConstantExpr::getCompare(pred, C1E, C2E));
    1821             :     }
    1822             : 
    1823          75 :     return ConstantVector::get(ResElts);
    1824             :   }
    1825             : 
    1826       16387 :   if (C1->getType()->isFloatingPointTy() &&
    1827             :       // Only call evaluateFCmpRelation if we have a constant expr to avoid
    1828             :       // infinite recursive loop
    1829          14 :       (isa<ConstantExpr>(C1) || isa<ConstantExpr>(C2))) {
    1830          14 :     int Result = -1;  // -1 = unknown, 0 = known false, 1 = known true.
    1831          14 :     switch (evaluateFCmpRelation(C1, C2)) {
    1832           0 :     default: llvm_unreachable("Unknown relation!");
    1833             :     case FCmpInst::FCMP_UNO:
    1834             :     case FCmpInst::FCMP_ORD:
    1835             :     case FCmpInst::FCMP_UEQ:
    1836             :     case FCmpInst::FCMP_UNE:
    1837             :     case FCmpInst::FCMP_ULT:
    1838             :     case FCmpInst::FCMP_UGT:
    1839             :     case FCmpInst::FCMP_ULE:
    1840             :     case FCmpInst::FCMP_UGE:
    1841             :     case FCmpInst::FCMP_TRUE:
    1842             :     case FCmpInst::FCMP_FALSE:
    1843             :     case FCmpInst::BAD_FCMP_PREDICATE:
    1844             :       break; // Couldn't determine anything about these constants.
    1845           0 :     case FCmpInst::FCMP_OEQ: // We know that C1 == C2
    1846           0 :       Result = (pred == FCmpInst::FCMP_UEQ || pred == FCmpInst::FCMP_OEQ ||
    1847           0 :                 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE ||
    1848           0 :                 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
    1849           0 :       break;
    1850           0 :     case FCmpInst::FCMP_OLT: // We know that C1 < C2
    1851           0 :       Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
    1852           0 :                 pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT ||
    1853           0 :                 pred == FCmpInst::FCMP_ULE || pred == FCmpInst::FCMP_OLE);
    1854           0 :       break;
    1855           0 :     case FCmpInst::FCMP_OGT: // We know that C1 > C2
    1856           0 :       Result = (pred == FCmpInst::FCMP_UNE || pred == FCmpInst::FCMP_ONE ||
    1857           0 :                 pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT ||
    1858           0 :                 pred == FCmpInst::FCMP_UGE || pred == FCmpInst::FCMP_OGE);
    1859           0 :       break;
    1860           0 :     case FCmpInst::FCMP_OLE: // We know that C1 <= C2
    1861             :       // We can only partially decide this relation.
    1862           0 :       if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
    1863             :         Result = 0;
    1864           0 :       else if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
    1865             :         Result = 1;
    1866             :       break;
    1867           0 :     case FCmpInst::FCMP_OGE: // We known that C1 >= C2
    1868             :       // We can only partially decide this relation.
    1869           0 :       if (pred == FCmpInst::FCMP_ULT || pred == FCmpInst::FCMP_OLT)
    1870             :         Result = 0;
    1871           0 :       else if (pred == FCmpInst::FCMP_UGT || pred == FCmpInst::FCMP_OGT)
    1872             :         Result = 1;
    1873             :       break;
    1874           0 :     case FCmpInst::FCMP_ONE: // We know that C1 != C2
    1875             :       // We can only partially decide this relation.
    1876           0 :       if (pred == FCmpInst::FCMP_OEQ || pred == FCmpInst::FCMP_UEQ)
    1877             :         Result = 0;
    1878           0 :       else if (pred == FCmpInst::FCMP_ONE || pred == FCmpInst::FCMP_UNE)
    1879             :         Result = 1;
    1880             :       break;
    1881             :     }
    1882             : 
    1883             :     // If we evaluated the result, return it now.
    1884             :     if (Result != -1)
    1885           0 :       return ConstantInt::get(ResultTy, Result);
    1886             : 
    1887             :   } else {
    1888             :     // Evaluate the relation between the two constants, per the predicate.
    1889       16359 :     int Result = -1;  // -1 = unknown, 0 = known false, 1 = known true.
    1890       16359 :     switch (evaluateICmpRelation(C1, C2,
    1891       16359 :                                  CmpInst::isSigned((CmpInst::Predicate)pred))) {
    1892           0 :     default: llvm_unreachable("Unknown relational!");
    1893             :     case ICmpInst::BAD_ICMP_PREDICATE:
    1894             :       break;  // Couldn't determine anything about these constants.
    1895       11109 :     case ICmpInst::ICMP_EQ:   // We know the constants are equal!
    1896             :       // If we know the constants are equal, we can decide the result of this
    1897             :       // computation precisely.
    1898       11109 :       Result = ICmpInst::isTrueWhenEqual((ICmpInst::Predicate)pred);
    1899       11109 :       break;
    1900          21 :     case ICmpInst::ICMP_ULT:
    1901             :       switch (pred) {
    1902             :       case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_ULE:
    1903             :         Result = 1; break;
    1904             :       case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_UGE:
    1905             :         Result = 0; break;
    1906             :       }
    1907             :       break;
    1908           4 :     case ICmpInst::ICMP_SLT:
    1909             :       switch (pred) {
    1910             :       case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SLE:
    1911             :         Result = 1; break;
    1912             :       case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SGE:
    1913             :         Result = 0; break;
    1914             :       }
    1915             :       break;
    1916        2541 :     case ICmpInst::ICMP_UGT:
    1917             :       switch (pred) {
    1918             :       case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_UGE:
    1919             :         Result = 1; break;
    1920             :       case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_ULE:
    1921             :         Result = 0; break;
    1922             :       }
    1923             :       break;
    1924           0 :     case ICmpInst::ICMP_SGT:
    1925             :       switch (pred) {
    1926             :       case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SGE:
    1927             :         Result = 1; break;
    1928             :       case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SLE:
    1929             :         Result = 0; break;
    1930             :       }
    1931             :       break;
    1932           0 :     case ICmpInst::ICMP_ULE:
    1933           0 :       if (pred == ICmpInst::ICMP_UGT) Result = 0;
    1934           0 :       if (pred == ICmpInst::ICMP_ULT || pred == ICmpInst::ICMP_ULE) Result = 1;
    1935             :       break;
    1936           0 :     case ICmpInst::ICMP_SLE:
    1937           0 :       if (pred == ICmpInst::ICMP_SGT) Result = 0;
    1938           0 :       if (pred == ICmpInst::ICMP_SLT || pred == ICmpInst::ICMP_SLE) Result = 1;
    1939             :       break;
    1940           0 :     case ICmpInst::ICMP_UGE:
    1941           0 :       if (pred == ICmpInst::ICMP_ULT) Result = 0;
    1942           0 :       if (pred == ICmpInst::ICMP_UGT || pred == ICmpInst::ICMP_UGE) Result = 1;
    1943             :       break;
    1944           0 :     case ICmpInst::ICMP_SGE:
    1945           0 :       if (pred == ICmpInst::ICMP_SLT) Result = 0;
    1946           0 :       if (pred == ICmpInst::ICMP_SGT || pred == ICmpInst::ICMP_SGE) Result = 1;
    1947             :       break;
    1948          64 :     case ICmpInst::ICMP_NE:
    1949          64 :       if (pred == ICmpInst::ICMP_EQ) Result = 0;
    1950          64 :       if (pred == ICmpInst::ICMP_NE) Result = 1;
    1951             :       break;
    1952             :     }
    1953             : 
    1954             :     // If we evaluated the result, return it now.
    1955       11170 :     if (Result != -1)
    1956       13702 :       return ConstantInt::get(ResultTy, Result);
    1957             : 
    1958             :     // If the right hand side is a bitcast, try using its inverse to simplify
    1959             :     // it by moving it to the left hand side.  We can't do this if it would turn
    1960             :     // a vector compare into a scalar compare or visa versa.
    1961        3042 :     if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {
    1962         385 :       Constant *CE2Op0 = CE2->getOperand(0);
    1963         404 :       if (CE2->getOpcode() == Instruction::BitCast &&
    1964          57 :           CE2->getType()->isVectorTy() == CE2Op0->getType()->isVectorTy()) {
    1965          19 :         Constant *Inverse = ConstantExpr::getBitCast(C1, CE2Op0->getType());
    1966          19 :         return ConstantExpr::getICmp(pred, Inverse, CE2Op0);
    1967             :       }
    1968             :     }
    1969             : 
    1970             :     // If the left hand side is an extension, try eliminating it.
    1971        5115 :     if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
    1972        2477 :       if ((CE1->getOpcode() == Instruction::SExt &&
    1973        4954 :            ICmpInst::isSigned((ICmpInst::Predicate)pred)) ||
    1974        3202 :           (CE1->getOpcode() == Instruction::ZExt &&
    1975         725 :            !ICmpInst::isSigned((ICmpInst::Predicate)pred))){
    1976          33 :         Constant *CE1Op0 = CE1->getOperand(0);
    1977          33 :         Constant *CE1Inverse = ConstantExpr::getTrunc(CE1, CE1Op0->getType());
    1978          33 :         if (CE1Inverse == CE1Op0) {
    1979             :           // Check whether we can safely truncate the right hand side.
    1980          33 :           Constant *C2Inverse = ConstantExpr::getTrunc(C2, CE1Op0->getType());
    1981          66 :           if (ConstantExpr::getCast(CE1->getOpcode(), C2Inverse,
    1982             :                                     C2->getType()) == C2)
    1983          33 :             return ConstantExpr::getICmp(pred, CE1Inverse, C2Inverse);
    1984             :         }
    1985             :       }
    1986             :     }
    1987             : 
    1988        7963 :     if ((!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) ||
    1989        2592 :         (C1->isNullValue() && !C2->isNullValue())) {
    1990             :       // If C2 is a constant expr and C1 isn't, flip them around and fold the
    1991             :       // other way if possible.
    1992             :       // Also, if C1 is null and C2 isn't, flip them around.
    1993          13 :       pred = ICmpInst::getSwappedPredicate((ICmpInst::Predicate)pred);
    1994          13 :       return ConstantExpr::getICmp(pred, C2, C1);
    1995             :     }
    1996             :   }
    1997             :   return nullptr;
    1998             : }
    1999             : 
    2000             : /// Test whether the given sequence of *normalized* indices is "inbounds".
    2001             : template<typename IndexTy>
    2002      236851 : static bool isInBoundsIndices(ArrayRef<IndexTy> Idxs) {
    2003             :   // No indices means nothing that could be out of bounds.
    2004      236851 :   if (Idxs.empty()) return true;
    2005             : 
    2006             :   // If the first index is zero, it's in bounds.
    2007      473702 :   if (cast<Constant>(Idxs[0])->isNullValue()) return true;
    2008             : 
    2009             :   // If the first index is one and all the rest are zero, it's in bounds,
    2010             :   // by the one-past-the-end rule.
    2011         654 :   if (!cast<ConstantInt>(Idxs[0])->isOne())
    2012             :     return false;
    2013          99 :   for (unsigned i = 1, e = Idxs.size(); i != e; ++i)
    2014         144 :     if (!cast<Constant>(Idxs[i])->isNullValue())
    2015             :       return false;
    2016             :   return true;
    2017             : }
    2018             : 
    2019             : /// Test whether a given ConstantInt is in-range for a SequentialType.
    2020    10484810 : static bool isIndexInRangeOfArrayType(uint64_t NumElements,
    2021             :                                       const ConstantInt *CI) {
    2022             :   // We cannot bounds check the index if it doesn't fit in an int64_t.
    2023    20969620 :   if (CI->getValue().getActiveBits() > 64)
    2024             :     return false;
    2025             : 
    2026             :   // A negative index or an index past the end of our sequential type is
    2027             :   // considered out-of-range.
    2028    10484810 :   int64_t IndexVal = CI->getSExtValue();
    2029    10484810 :   if (IndexVal < 0 || (NumElements > 0 && (uint64_t)IndexVal >= NumElements))
    2030             :     return false;
    2031             : 
    2032             :   // Otherwise, it is in-range.
    2033    10484534 :   return true;
    2034             : }
    2035             : 
    2036    10541859 : Constant *llvm::ConstantFoldGetElementPtr(Type *PointeeTy, Constant *C,
    2037             :                                           bool InBounds,
    2038             :                                           Optional<unsigned> InRangeIndex,
    2039             :                                           ArrayRef<Value *> Idxs) {
    2040    10541859 :   if (Idxs.empty()) return C;
    2041             : 
    2042    21083714 :   if (isa<UndefValue>(C)) {
    2043          86 :     Type *GEPTy = GetElementPtrInst::getGEPReturnType(
    2044          43 :         C, makeArrayRef((Value * const *)Idxs.data(), Idxs.size()));
    2045          43 :     return UndefValue::get(GEPTy);
    2046             :   }
    2047             : 
    2048    21083628 :   Constant *Idx0 = cast<Constant>(Idxs[0]);
    2049    10548115 :   if (Idxs.size() == 1 && (Idx0->isNullValue() || isa<UndefValue>(Idx0)))
    2050             :     return C;
    2051             : 
    2052    10541335 :   if (C->isNullValue()) {
    2053        1906 :     bool isNull = true;
    2054        3425 :     for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
    2055       13564 :       if (!isa<UndefValue>(Idxs[i]) &&
    2056        6782 :           !cast<Constant>(Idxs[i])->isNullValue()) {
    2057             :         isNull = false;
    2058             :         break;
    2059             :       }
    2060        1906 :     if (isNull) {
    2061         102 :       PointerType *PtrTy = cast<PointerType>(C->getType()->getScalarType());
    2062          34 :       Type *Ty = GetElementPtrInst::getIndexedType(PointeeTy, Idxs);
    2063             : 
    2064             :       assert(Ty && "Invalid indices for GEP!");
    2065          34 :       Type *GEPTy = PointerType::get(Ty, PtrTy->getAddressSpace());
    2066          36 :       if (VectorType *VT = dyn_cast<VectorType>(C->getType()))
    2067           2 :         GEPTy = VectorType::get(GEPTy, VT->getNumElements());
    2068          34 :       return Constant::getNullValue(GEPTy);
    2069             :     }
    2070             :   }
    2071             : 
    2072    10546320 :   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
    2073             :     // Combine Indices - If the source pointer to this getelementptr instruction
    2074             :     // is a getelementptr instruction, combine the indices of the two
    2075             :     // getelementptr instructions into a single instruction.
    2076             :     //
    2077        5019 :     if (CE->getOpcode() == Instruction::GetElementPtr) {
    2078        1333 :       gep_type_iterator LastI = gep_type_end(CE);
    2079        4249 :       for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
    2080        4249 :            I != E; ++I)
    2081        2916 :         LastI = I;
    2082             : 
    2083             :       // We cannot combine indices if doing so would take us outside of an
    2084             :       // array or vector.  Doing otherwise could trick us if we evaluated such a
    2085             :       // GEP as part of a load.
    2086             :       //
    2087             :       // e.g. Consider if the original GEP was:
    2088             :       // i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c,
    2089             :       //                    i32 0, i32 0, i64 0)
    2090             :       //
    2091             :       // If we then tried to offset it by '8' to get to the third element,
    2092             :       // an i8, we should *not* get:
    2093             :       // i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c,
    2094             :       //                    i32 0, i32 0, i64 8)
    2095             :       //
    2096             :       // This GEP tries to index array element '8  which runs out-of-bounds.
    2097             :       // Subsequent evaluation would get confused and produce erroneous results.
    2098             :       //
    2099             :       // The following prohibits such a GEP from being formed by checking to see
    2100             :       // if the index is in-range with respect to an array.
    2101             :       // TODO: This code may be extended to handle vectors as well.
    2102        1333 :       bool PerformFold = false;
    2103        1333 :       if (Idx0->isNullValue())
    2104             :         PerformFold = true;
    2105         967 :       else if (LastI.isSequential())
    2106        1800 :         if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx0))
    2107        1772 :           PerformFold = (!LastI.isBoundedSequential() ||
    2108         886 :                          isIndexInRangeOfArrayType(
    2109         774 :                              LastI.getSequentialNumElements(), CI)) &&
    2110        1548 :                         !CE->getOperand(CE->getNumOperands() - 1)
    2111             :                              ->getType()
    2112        1548 :                              ->isVectorTy();
    2113             : 
    2114             :       if (PerformFold) {
    2115        2278 :         SmallVector<Value*, 16> NewIndices;
    2116        2278 :         NewIndices.reserve(Idxs.size() + CE->getNumOperands());
    2117        2278 :         NewIndices.append(CE->op_begin() + 1, CE->op_end() - 1);
    2118             : 
    2119             :         // Add the last index of the source with the first index of the new GEP.
    2120             :         // Make sure to handle the case when they are actually different types.
    2121        2278 :         Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
    2122             :         // Otherwise it must be an array.
    2123        1139 :         if (!Idx0->isNullValue()) {
    2124         773 :           Type *IdxTy = Combined->getType();
    2125         773 :           if (IdxTy != Idx0->getType()) {
    2126             :             unsigned CommonExtendedWidth =
    2127         225 :                 std::max(IdxTy->getIntegerBitWidth(),
    2128         375 :                          Idx0->getType()->getIntegerBitWidth());
    2129         150 :             CommonExtendedWidth = std::max(CommonExtendedWidth, 64U);
    2130             : 
    2131             :             Type *CommonTy =
    2132          75 :                 Type::getIntNTy(IdxTy->getContext(), CommonExtendedWidth);
    2133          75 :             Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, CommonTy);
    2134          75 :             Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined, CommonTy);
    2135          75 :             Combined = ConstantExpr::get(Instruction::Add, C1, C2);
    2136             :           } else {
    2137         698 :             Combined =
    2138             :               ConstantExpr::get(Instruction::Add, Idx0, Combined);
    2139             :           }
    2140             :         }
    2141             : 
    2142        1139 :         NewIndices.push_back(Combined);
    2143        1139 :         NewIndices.append(Idxs.begin() + 1, Idxs.end());
    2144             : 
    2145             :         // The combined GEP normally inherits its index inrange attribute from
    2146             :         // the inner GEP, but if the inner GEP's last index was adjusted by the
    2147             :         // outer GEP, any inbounds attribute on that index is invalidated.
    2148        3417 :         Optional<unsigned> IRIndex = cast<GEPOperator>(CE)->getInRangeIndex();
    2149        1151 :         if (IRIndex && *IRIndex == CE->getNumOperands() - 2 && !Idx0->isNullValue())
    2150           6 :           IRIndex = None;
    2151             : 
    2152        7973 :         return ConstantExpr::getGetElementPtr(
    2153             :             cast<GEPOperator>(CE)->getSourceElementType(), CE->getOperand(0),
    2154        2329 :             NewIndices, InBounds && cast<GEPOperator>(CE)->isInBounds(),
    2155        1139 :             IRIndex);
    2156             :       }
    2157             :     }
    2158             : 
    2159             :     // Attempt to fold casts to the same type away.  For example, folding:
    2160             :     //
    2161             :     //   i32* getelementptr ([2 x i32]* bitcast ([3 x i32]* %X to [2 x i32]*),
    2162             :     //                       i64 0, i64 0)
    2163             :     // into:
    2164             :     //
    2165             :     //   i32* getelementptr ([3 x i32]* %X, i64 0, i64 0)
    2166             :     //
    2167             :     // Don't fold if the cast is changing address spaces.
    2168        3880 :     if (CE->isCast() && Idxs.size() > 1 && Idx0->isNullValue()) {
    2169             :       PointerType *SrcPtrTy =
    2170        1076 :         dyn_cast<PointerType>(CE->getOperand(0)->getType());
    2171        1076 :       PointerType *DstPtrTy = dyn_cast<PointerType>(CE->getType());
    2172         538 :       if (SrcPtrTy && DstPtrTy) {
    2173             :         ArrayType *SrcArrayTy =
    2174         724 :           dyn_cast<ArrayType>(SrcPtrTy->getElementType());
    2175             :         ArrayType *DstArrayTy =
    2176         724 :           dyn_cast<ArrayType>(DstPtrTy->getElementType());
    2177         362 :         if (SrcArrayTy && DstArrayTy
    2178         101 :             && SrcArrayTy->getElementType() == DstArrayTy->getElementType()
    2179         548 :             && SrcPtrTy->getAddressSpace() == DstPtrTy->getAddressSpace())
    2180          75 :           return ConstantExpr::getGetElementPtr(SrcArrayTy,
    2181             :                                                 (Constant *)CE->getOperand(0),
    2182          25 :                                                 Idxs, InBounds, InRangeIndex);
    2183             :       }
    2184             :     }
    2185             :   }
    2186             : 
    2187             :   // Check to see if any array indices are not within the corresponding
    2188             :   // notional array or vector bounds. If so, try to determine if they can be
    2189             :   // factored out into preceding dimensions.
    2190    10540137 :   SmallVector<Constant *, 8> NewIdxs;
    2191    10540137 :   Type *Ty = PointeeTy;
    2192    10540137 :   Type *Prev = C->getType();
    2193    21080274 :   bool Unknown = !isa<ConstantInt>(Idxs[0]);
    2194    21106188 :   for (unsigned i = 1, e = Idxs.size(); i != e;
    2195    21132102 :        Prev = Ty, Ty = cast<CompositeType>(Ty)->getTypeAtIndex(Idxs[i]), ++i) {
    2196    31698086 :     auto *CI = dyn_cast<ConstantInt>(Idxs[i]);
    2197          67 :     if (!CI) {
    2198             :       // We don't know if it's in range or not.
    2199          67 :       Unknown = true;
    2200    10566065 :       continue;
    2201             :     }
    2202    10637852 :     if (InRangeIndex && i == *InRangeIndex + 1) {
    2203             :       // If an index is marked inrange, we cannot apply this canonicalization to
    2204             :       // the following index, as that will cause the inrange index to point to
    2205             :       // the wrong element.
    2206       23956 :       continue;
    2207             :     }
    2208    21142145 :     if (isa<StructType>(Ty)) {
    2209             :       // The verify makes sure that GEPs into a struct are in range.
    2210       58089 :       continue;
    2211             :     }
    2212    20967878 :     auto *STy = cast<SequentialType>(Ty);
    2213    20967893 :     if (isa<VectorType>(STy)) {
    2214             :       // There can be awkward padding in after a non-power of two vector.
    2215          15 :       Unknown = true;
    2216          15 :       continue;
    2217             :     }
    2218    10483924 :     if (isIndexInRangeOfArrayType(STy->getNumElements(), CI))
    2219             :       // It's in range, skip to the next index.
    2220    10483766 :       continue;
    2221         348 :     if (isa<StructType>(Prev)) {
    2222             :       // It's out of range, but the prior dimension is a struct
    2223             :       // so we can't do anything about it.
    2224          32 :       Unknown = true;
    2225          32 :       continue;
    2226             :     }
    2227         199 :     if (CI->getSExtValue() < 0) {
    2228             :       // It's out of range and negative, don't try to factor it.
    2229          73 :       Unknown = true;
    2230          73 :       continue;
    2231             :     }
    2232             :     // It's out of range, but we can factor it into the prior
    2233             :     // dimension.
    2234          53 :     NewIdxs.resize(Idxs.size());
    2235             :     // Determine the number of elements in our sequential type.
    2236         106 :     uint64_t NumElements = STy->getArrayNumElements();
    2237             : 
    2238          53 :     ConstantInt *Factor = ConstantInt::get(CI->getType(), NumElements);
    2239         106 :     NewIdxs[i] = ConstantExpr::getSRem(CI, Factor);
    2240             : 
    2241         210 :     Constant *PrevIdx = NewIdxs[i-1] ? NewIdxs[i-1] :
    2242         208 :                            cast<Constant>(Idxs[i - 1]);
    2243          53 :     Constant *Div = ConstantExpr::getSDiv(CI, Factor);
    2244             : 
    2245             :     unsigned CommonExtendedWidth =
    2246         212 :         std::max(PrevIdx->getType()->getIntegerBitWidth(),
    2247         265 :                  Div->getType()->getIntegerBitWidth());
    2248         106 :     CommonExtendedWidth = std::max(CommonExtendedWidth, 64U);
    2249             : 
    2250             :     // Before adding, extend both operands to i64 to avoid
    2251             :     // overflow trouble.
    2252          53 :     if (!PrevIdx->getType()->isIntegerTy(CommonExtendedWidth))
    2253          20 :       PrevIdx = ConstantExpr::getSExt(
    2254          20 :           PrevIdx, Type::getIntNTy(Div->getContext(), CommonExtendedWidth));
    2255          53 :     if (!Div->getType()->isIntegerTy(CommonExtendedWidth))
    2256          12 :       Div = ConstantExpr::getSExt(
    2257          12 :           Div, Type::getIntNTy(Div->getContext(), CommonExtendedWidth));
    2258             : 
    2259         106 :     NewIdxs[i - 1] = ConstantExpr::getAdd(PrevIdx, Div);
    2260             :   }
    2261             : 
    2262             :   // If we did any factoring, start over with the adjusted indices.
    2263    10540137 :   if (!NewIdxs.empty()) {
    2264         353 :     for (unsigned i = 0, e = Idxs.size(); i != e; ++i)
    2265         448 :       if (!NewIdxs[i]) NewIdxs[i] = cast<Constant>(Idxs[i]);
    2266         196 :     return ConstantExpr::getGetElementPtr(PointeeTy, C, NewIdxs, InBounds,
    2267          49 :                                           InRangeIndex);
    2268             :   }
    2269             : 
    2270             :   // If all indices are known integers and normalized, we can do a simple
    2271             :   // check for the "inbounds" property.
    2272    10540088 :   if (!Unknown && !InBounds)
    2273      479031 :     if (auto *GV = dyn_cast<GlobalVariable>(C))
    2274      473842 :       if (!GV->hasExternalWeakLinkage() && isInBoundsIndices(Idxs))
    2275      473368 :         return ConstantExpr::getGetElementPtr(PointeeTy, C, Idxs,
    2276      236684 :                                               /*InBounds=*/true, InRangeIndex);
    2277             : 
    2278             :   return nullptr;
    2279             : }

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