C++ BinaryOperator::setHasNoSignedWrap方法代码示例

TEST(CloneInstruction, OverflowBits) {
  LLVMContext context;
  Value *V = new Argument(Type::getInt32Ty(context));

  BinaryOperator *Add = BinaryOperator::Create(Instruction::Add, V, V);
  BinaryOperator *Sub = BinaryOperator::Create(Instruction::Sub, V, V);
  BinaryOperator *Mul = BinaryOperator::Create(Instruction::Mul, V, V);

  EXPECT_FALSE(cast<BinaryOperator>(Add->clone())->hasNoUnsignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Add->clone())->hasNoSignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Sub->clone())->hasNoUnsignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Sub->clone())->hasNoSignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Mul->clone())->hasNoUnsignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Mul->clone())->hasNoSignedWrap());

  Add->setHasNoUnsignedWrap();
  Sub->setHasNoUnsignedWrap();
  Mul->setHasNoUnsignedWrap();

  EXPECT_TRUE(cast<BinaryOperator>(Add->clone())->hasNoUnsignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Add->clone())->hasNoSignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Sub->clone())->hasNoUnsignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Sub->clone())->hasNoSignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Mul->clone())->hasNoUnsignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Mul->clone())->hasNoSignedWrap());

  Add->setHasNoSignedWrap();
  Sub->setHasNoSignedWrap();
  Mul->setHasNoSignedWrap();

  EXPECT_TRUE(cast<BinaryOperator>(Add->clone())->hasNoUnsignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Add->clone())->hasNoSignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Sub->clone())->hasNoUnsignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Sub->clone())->hasNoSignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Mul->clone())->hasNoUnsignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Mul->clone())->hasNoSignedWrap());

  Add->setHasNoUnsignedWrap(false);
  Sub->setHasNoUnsignedWrap(false);
  Mul->setHasNoUnsignedWrap(false);

  EXPECT_FALSE(cast<BinaryOperator>(Add->clone())->hasNoUnsignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Add->clone())->hasNoSignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Sub->clone())->hasNoUnsignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Sub->clone())->hasNoSignedWrap());
  EXPECT_FALSE(cast<BinaryOperator>(Mul->clone())->hasNoUnsignedWrap());
  EXPECT_TRUE(cast<BinaryOperator>(Mul->clone())->hasNoSignedWrap());
}

// Implementation of  r = rand (); a = b - r; a = a - c; a = a + r
void Substitution::subRand2(BinaryOperator *bo) {
  BinaryOperator *op = NULL;

  if (bo->getOpcode() == Instruction::Sub) {
    Type *ty = bo->getType();
    ConstantInt *co =
        (ConstantInt *)ConstantInt::get(ty, llvm::cryptoutils->get_uint64_t());
    op =
        BinaryOperator::Create(Instruction::Sub, bo->getOperand(0), co, "", bo);
    op =
        BinaryOperator::Create(Instruction::Sub, op, bo->getOperand(1), "", bo);
    op = BinaryOperator::Create(Instruction::Add, op, co, "", bo);

    // Check signed wrap
    op->setHasNoSignedWrap(bo->hasNoSignedWrap());
    op->setHasNoUnsignedWrap(bo->hasNoUnsignedWrap());

    bo->replaceAllUsesWith(op);
  }
  /* else {
      Type *ty = bo->getType();
      ConstantFP *co =
  (ConstantFP*)ConstantFP::get(ty,(float)llvm::cryptoutils->get_uint64_t());
      op = BinaryOperator::Create(Instruction::FSub,bo->getOperand(0),co,"",bo);
      op = BinaryOperator::Create(Instruction::FSub,op,bo->getOperand(1),"",bo);
      op = BinaryOperator::Create(Instruction::FAdd,op,co,"",bo);
  } */
}

Value *ConstantOffsetExtractor::removeConstOffset(unsigned ChainIndex) {
  if (ChainIndex == 0) {
    assert(isa<ConstantInt>(UserChain[ChainIndex]));
    return ConstantInt::getNullValue(UserChain[ChainIndex]->getType());
  }

  BinaryOperator *BO = cast<BinaryOperator>(UserChain[ChainIndex]);
  unsigned OpNo = (BO->getOperand(0) == UserChain[ChainIndex - 1] ? 0 : 1);
  assert(BO->getOperand(OpNo) == UserChain[ChainIndex - 1]);
  Value *NextInChain = removeConstOffset(ChainIndex - 1);
  Value *TheOther = BO->getOperand(1 - OpNo);

  // If NextInChain is 0 and not the LHS of a sub, we can simplify the
  // sub-expression to be just TheOther.
  if (ConstantInt *CI = dyn_cast<ConstantInt>(NextInChain)) {
    if (CI->isZero() && !(BO->getOpcode() == Instruction::Sub && OpNo == 0))
      return TheOther;
  }

  if (BO->getOpcode() == Instruction::Or) {
    // Rebuild "or" as "add", because "or" may be invalid for the new
    // epxression.
    //
    // For instance, given
    //   a | (b + 5) where a and b + 5 have no common bits,
    // we can extract 5 as the constant offset.
    //
    // However, reusing the "or" in the new index would give us
    //   (a | b) + 5
    // which does not equal a | (b + 5).
    //
    // Replacing the "or" with "add" is fine, because
    //   a | (b + 5) = a + (b + 5) = (a + b) + 5
    if (OpNo == 0) {
      return BinaryOperator::CreateAdd(NextInChain, TheOther, BO->getName(),
                                       IP);
    } else {
      return BinaryOperator::CreateAdd(TheOther, NextInChain, BO->getName(),
                                       IP);
    }
  }

  // We can reuse BO in this case, because the new expression shares the same
  // instruction type and BO is used at most once.
  assert(BO->getNumUses() <= 1 &&
         "distributeExtsAndCloneChain clones each BinaryOperator in "
         "UserChain, so no one should be used more than "
         "once");
  BO->setOperand(OpNo, NextInChain);
  BO->setHasNoSignedWrap(false);
  BO->setHasNoUnsignedWrap(false);
  // Make sure it appears after all instructions we've inserted so far.
  BO->moveBefore(IP);
  return BO;
}

Value *AMDGPUCodeGenPrepare::copyFlags(
    const BinaryOperator &I, Value *V) const {
  assert(isa<BinaryOperator>(V) && "V must be binary operation");

  BinaryOperator *BinOp = cast<BinaryOperator>(V);
  if (isa<OverflowingBinaryOperator>(BinOp)) {
    BinOp->setHasNoSignedWrap(I.hasNoSignedWrap());
    BinOp->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
  } else if (isa<PossiblyExactOperator>(BinOp))
    BinOp->setIsExact(I.isExact());

  return V;
}

// Implementation of a = b + (-c)
void Substitution::subNeg(BinaryOperator *bo) {
  BinaryOperator *op = NULL;

  if (bo->getOpcode() == Instruction::Sub) {
    op = BinaryOperator::CreateNeg(bo->getOperand(1), "", bo);
    op =
        BinaryOperator::Create(Instruction::Add, bo->getOperand(0), op, "", bo);

    // Check signed wrap
    op->setHasNoSignedWrap(bo->hasNoSignedWrap());
    op->setHasNoUnsignedWrap(bo->hasNoUnsignedWrap());
  } else {
    op = BinaryOperator::CreateFNeg(bo->getOperand(1), "", bo);
    op = BinaryOperator::Create(Instruction::FAdd, bo->getOperand(0), op, "",
                                bo);
  }

  bo->replaceAllUsesWith(op);
}

Instruction *InstCombiner::visitSub(BinaryOperator &I) {
  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);

  if (Value *V = SimplifySubInst(Op0, Op1, I.hasNoSignedWrap(),
                                 I.hasNoUnsignedWrap(), TD))
    return ReplaceInstUsesWith(I, V);

  // (A*B)-(A*C) -> A*(B-C) etc
  if (Value *V = SimplifyUsingDistributiveLaws(I))
    return ReplaceInstUsesWith(I, V);

  // If this is a 'B = x-(-A)', change to B = x+A.  This preserves NSW/NUW.
  if (Value *V = dyn_castNegVal(Op1)) {
    BinaryOperator *Res = BinaryOperator::CreateAdd(Op0, V);
    Res->setHasNoSignedWrap(I.hasNoSignedWrap());
    Res->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
    return Res;
  }

  if (I.getType()->isIntegerTy(1))
    return BinaryOperator::CreateXor(Op0, Op1);

  // Replace (-1 - A) with (~A).
  if (match(Op0, m_AllOnes()))
    return BinaryOperator::CreateNot(Op1);
  
  if (ConstantInt *C = dyn_cast<ConstantInt>(Op0)) {
    // C - ~X == X + (1+C)
    Value *X = 0;
    if (match(Op1, m_Not(m_Value(X))))
      return BinaryOperator::CreateAdd(X, AddOne(C));

    // -(X >>u 31) -> (X >>s 31)
    // -(X >>s 31) -> (X >>u 31)
    if (C->isZero()) {
      Value *X; ConstantInt *CI;
      if (match(Op1, m_LShr(m_Value(X), m_ConstantInt(CI))) &&
          // Verify we are shifting out everything but the sign bit.
          CI->getValue() == I.getType()->getPrimitiveSizeInBits()-1)
        return BinaryOperator::CreateAShr(X, CI);

      if (match(Op1, m_AShr(m_Value(X), m_ConstantInt(CI))) &&
          // Verify we are shifting out everything but the sign bit.
          CI->getValue() == I.getType()->getPrimitiveSizeInBits()-1)
        return BinaryOperator::CreateLShr(X, CI);
    }

    // Try to fold constant sub into select arguments.
    if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
      if (Instruction *R = FoldOpIntoSelect(I, SI))
        return R;

    // C - zext(bool) -> bool ? C - 1 : C
    if (ZExtInst *ZI = dyn_cast<ZExtInst>(Op1))
      if (ZI->getSrcTy()->isIntegerTy(1))
        return SelectInst::Create(ZI->getOperand(0), SubOne(C), C);

    // C-(X+C2) --> (C-C2)-X
    ConstantInt *C2;
    if (match(Op1, m_Add(m_Value(X), m_ConstantInt(C2))))
      return BinaryOperator::CreateSub(ConstantExpr::getSub(C, C2), X);
  }

  
  { Value *Y;
    // X-(X+Y) == -Y    X-(Y+X) == -Y
    if (match(Op1, m_Add(m_Specific(Op0), m_Value(Y))) ||
        match(Op1, m_Add(m_Value(Y), m_Specific(Op0))))
      return BinaryOperator::CreateNeg(Y);
    
    // (X-Y)-X == -Y
    if (match(Op0, m_Sub(m_Specific(Op1), m_Value(Y))))
      return BinaryOperator::CreateNeg(Y);
  }
  
  if (Op1->hasOneUse()) {
    Value *X = 0, *Y = 0, *Z = 0;
    Constant *C = 0;
    ConstantInt *CI = 0;

    // (X - (Y - Z))  -->  (X + (Z - Y)).
    if (match(Op1, m_Sub(m_Value(Y), m_Value(Z))))
      return BinaryOperator::CreateAdd(Op0,
                                      Builder->CreateSub(Z, Y, Op1->getName()));

    // (X - (X & Y))   -->   (X & ~Y)
    //
    if (match(Op1, m_And(m_Value(Y), m_Specific(Op0))) ||
        match(Op1, m_And(m_Specific(Op0), m_Value(Y))))
      return BinaryOperator::CreateAnd(Op0,
                                  Builder->CreateNot(Y, Y->getName() + ".not"));
    
    // 0 - (X sdiv C)  -> (X sdiv -C)
    if (match(Op1, m_SDiv(m_Value(X), m_Constant(C))) &&
        match(Op0, m_Zero()))
      return BinaryOperator::CreateSDiv(X, ConstantExpr::getNeg(C));

    // 0 - (X << Y)  -> (-X << Y)   when X is freely negatable.
    if (match(Op1, m_Shl(m_Value(X), m_Value(Y))) && match(Op0, m_Zero()))
      if (Value *XNeg = dyn_castNegVal(X))
//.........这里部分代码省略.........

bool SimplifyIndvar::eliminateOverflowIntrinsic(CallInst *CI) {
  auto *F = CI->getCalledFunction();
  if (!F)
    return false;

  typedef const SCEV *(ScalarEvolution::*OperationFunctionTy)(
      const SCEV *, const SCEV *, SCEV::NoWrapFlags, unsigned);
  typedef const SCEV *(ScalarEvolution::*ExtensionFunctionTy)(
      const SCEV *, Type *, unsigned);

  OperationFunctionTy Operation;
  ExtensionFunctionTy Extension;

  Instruction::BinaryOps RawOp;

  // We always have exactly one of nsw or nuw.  If NoSignedOverflow is false, we
  // have nuw.
  bool NoSignedOverflow;

  switch (F->getIntrinsicID()) {
  default:
    return false;

  case Intrinsic::sadd_with_overflow:
    Operation = &ScalarEvolution::getAddExpr;
    Extension = &ScalarEvolution::getSignExtendExpr;
    RawOp = Instruction::Add;
    NoSignedOverflow = true;
    break;

  case Intrinsic::uadd_with_overflow:
    Operation = &ScalarEvolution::getAddExpr;
    Extension = &ScalarEvolution::getZeroExtendExpr;
    RawOp = Instruction::Add;
    NoSignedOverflow = false;
    break;

  case Intrinsic::ssub_with_overflow:
    Operation = &ScalarEvolution::getMinusSCEV;
    Extension = &ScalarEvolution::getSignExtendExpr;
    RawOp = Instruction::Sub;
    NoSignedOverflow = true;
    break;

  case Intrinsic::usub_with_overflow:
    Operation = &ScalarEvolution::getMinusSCEV;
    Extension = &ScalarEvolution::getZeroExtendExpr;
    RawOp = Instruction::Sub;
    NoSignedOverflow = false;
    break;
  }

  const SCEV *LHS = SE->getSCEV(CI->getArgOperand(0));
  const SCEV *RHS = SE->getSCEV(CI->getArgOperand(1));

  auto *NarrowTy = cast<IntegerType>(LHS->getType());
  auto *WideTy =
    IntegerType::get(NarrowTy->getContext(), NarrowTy->getBitWidth() * 2);

  const SCEV *A =
      (SE->*Extension)((SE->*Operation)(LHS, RHS, SCEV::FlagAnyWrap, 0),
                       WideTy, 0);
  const SCEV *B =
      (SE->*Operation)((SE->*Extension)(LHS, WideTy, 0),
                       (SE->*Extension)(RHS, WideTy, 0), SCEV::FlagAnyWrap, 0);

  if (A != B)
    return false;

  // Proved no overflow, nuke the overflow check and, if possible, the overflow
  // intrinsic as well.

  BinaryOperator *NewResult = BinaryOperator::Create(
      RawOp, CI->getArgOperand(0), CI->getArgOperand(1), "", CI);

  if (NoSignedOverflow)
    NewResult->setHasNoSignedWrap(true);
  else
    NewResult->setHasNoUnsignedWrap(true);

  SmallVector<ExtractValueInst *, 4> ToDelete;

  for (auto *U : CI->users()) {
    if (auto *EVI = dyn_cast<ExtractValueInst>(U)) {
      if (EVI->getIndices()[0] == 1)
        EVI->replaceAllUsesWith(ConstantInt::getFalse(CI->getContext()));
      else {
        assert(EVI->getIndices()[0] == 0 && "Only two possibilities!");
        EVI->replaceAllUsesWith(NewResult);
      }
      ToDelete.push_back(EVI);
    }
  }

  for (auto *EVI : ToDelete)
    EVI->eraseFromParent();

  if (CI->use_empty())
    CI->eraseFromParent();

//.........这里部分代码省略.........

/// FoldSelectIntoOp - Try fold the select into one of the operands to
/// facilitate further optimization.
Instruction *InstCombiner::FoldSelectIntoOp(SelectInst &SI, Value *TrueVal,
                                            Value *FalseVal) {
  // See the comment above GetSelectFoldableOperands for a description of the
  // transformation we are doing here.
  if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) {
    if (TVI->hasOneUse() && TVI->getNumOperands() == 2 &&
        !isa<Constant>(FalseVal)) {
      if (unsigned SFO = GetSelectFoldableOperands(TVI)) {
        unsigned OpToFold = 0;
        if ((SFO & 1) && FalseVal == TVI->getOperand(0)) {
          OpToFold = 1;
        } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) {
          OpToFold = 2;
        }

        if (OpToFold) {
          Constant *C = GetSelectFoldableConstant(TVI);
          Value *OOp = TVI->getOperand(2-OpToFold);
          // Avoid creating select between 2 constants unless it's selecting
          // between 0, 1 and -1.
          if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
            Value *NewSel = Builder->CreateSelect(SI.getCondition(), OOp, C);
            NewSel->takeName(TVI);
            BinaryOperator *TVI_BO = cast<BinaryOperator>(TVI);
            BinaryOperator *BO = BinaryOperator::Create(TVI_BO->getOpcode(),
                                                        FalseVal, NewSel);
            if (isa<PossiblyExactOperator>(BO))
              BO->setIsExact(TVI_BO->isExact());
            if (isa<OverflowingBinaryOperator>(BO)) {
              BO->setHasNoUnsignedWrap(TVI_BO->hasNoUnsignedWrap());
              BO->setHasNoSignedWrap(TVI_BO->hasNoSignedWrap());
            }
            return BO;
          }
        }
      }
    }
  }

  if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) {
    if (FVI->hasOneUse() && FVI->getNumOperands() == 2 &&
        !isa<Constant>(TrueVal)) {
      if (unsigned SFO = GetSelectFoldableOperands(FVI)) {
        unsigned OpToFold = 0;
        if ((SFO & 1) && TrueVal == FVI->getOperand(0)) {
          OpToFold = 1;
        } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) {
          OpToFold = 2;
        }

        if (OpToFold) {
          Constant *C = GetSelectFoldableConstant(FVI);
          Value *OOp = FVI->getOperand(2-OpToFold);
          // Avoid creating select between 2 constants unless it's selecting
          // between 0, 1 and -1.
          if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) {
            Value *NewSel = Builder->CreateSelect(SI.getCondition(), C, OOp);
            NewSel->takeName(FVI);
            BinaryOperator *FVI_BO = cast<BinaryOperator>(FVI);
            BinaryOperator *BO = BinaryOperator::Create(FVI_BO->getOpcode(),
                                                        TrueVal, NewSel);
            if (isa<PossiblyExactOperator>(BO))
              BO->setIsExact(FVI_BO->isExact());
            if (isa<OverflowingBinaryOperator>(BO)) {
              BO->setHasNoUnsignedWrap(FVI_BO->hasNoUnsignedWrap());
              BO->setHasNoSignedWrap(FVI_BO->hasNoSignedWrap());
            }
            return BO;
          }
        }
      }
    }
  }

  return nullptr;
}

/// Rebuild a new instruction just like 'I' but with the new operands given.
/// In the event of type mismatch, the type of the operands is correct.
static Value *BuildNew(Instruction *I, ArrayRef<Value*> NewOps) {
  // We don't want to use the IRBuilder here because we want the replacement
  // instructions to appear next to 'I', not the builder's insertion point.
  switch (I->getOpcode()) {
    case Instruction::Add:
    case Instruction::FAdd:
    case Instruction::Sub:
    case Instruction::FSub:
    case Instruction::Mul:
    case Instruction::FMul:
    case Instruction::UDiv:
    case Instruction::SDiv:
    case Instruction::FDiv:
    case Instruction::URem:
    case Instruction::SRem:
    case Instruction::FRem:
    case Instruction::Shl:
    case Instruction::LShr:
    case Instruction::AShr:
    case Instruction::And:
    case Instruction::Or:
    case Instruction::Xor: {
      BinaryOperator *BO = cast<BinaryOperator>(I);
      assert(NewOps.size() == 2 && "binary operator with #ops != 2");
      BinaryOperator *New =
          BinaryOperator::Create(cast<BinaryOperator>(I)->getOpcode(),
                                 NewOps[0], NewOps[1], "", BO);
      if (isa<OverflowingBinaryOperator>(BO)) {
        New->setHasNoUnsignedWrap(BO->hasNoUnsignedWrap());
        New->setHasNoSignedWrap(BO->hasNoSignedWrap());
      }
      if (isa<PossiblyExactOperator>(BO)) {
        New->setIsExact(BO->isExact());
      }
      return New;
    }
    case Instruction::ICmp:
      assert(NewOps.size() == 2 && "icmp with #ops != 2");
      return new ICmpInst(I, cast<ICmpInst>(I)->getPredicate(),
                          NewOps[0], NewOps[1]);
    case Instruction::FCmp:
      assert(NewOps.size() == 2 && "fcmp with #ops != 2");
      return new FCmpInst(I, cast<FCmpInst>(I)->getPredicate(),
                          NewOps[0], NewOps[1]);
    case Instruction::Trunc:
    case Instruction::ZExt:
    case Instruction::SExt:
    case Instruction::FPToUI:
    case Instruction::FPToSI:
    case Instruction::UIToFP:
    case Instruction::SIToFP:
    case Instruction::FPTrunc:
    case Instruction::FPExt: {
      // It's possible that the mask has a different number of elements from
      // the original cast. We recompute the destination type to match the mask.
      Type *DestTy =
          VectorType::get(I->getType()->getScalarType(),
                          NewOps[0]->getType()->getVectorNumElements());
      assert(NewOps.size() == 1 && "cast with #ops != 1");
      return CastInst::Create(cast<CastInst>(I)->getOpcode(), NewOps[0], DestTy,
                              "", I);
    }
    case Instruction::GetElementPtr: {
      Value *Ptr = NewOps[0];
      ArrayRef<Value*> Idx = NewOps.slice(1);
      GetElementPtrInst *GEP = GetElementPtrInst::Create(Ptr, Idx, "", I);
      GEP->setIsInBounds(cast<GetElementPtrInst>(I)->isInBounds());
      return GEP;
    }
  }
  llvm_unreachable("failed to rebuild vector instructions");
}

Instruction *InstCombiner::visitMul(BinaryOperator &I) {
  bool Changed = SimplifyAssociativeOrCommutative(I);
  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);

  if (Value *V = SimplifyMulInst(Op0, Op1, TD))
    return ReplaceInstUsesWith(I, V);

  if (Value *V = SimplifyUsingDistributiveLaws(I))
    return ReplaceInstUsesWith(I, V);

  if (match(Op1, m_AllOnes()))  // X * -1 == 0 - X
    return BinaryOperator::CreateNeg(Op0, I.getName());
  
  if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
    
    // ((X << C1)*C2) == (X * (C2 << C1))
    if (BinaryOperator *SI = dyn_cast<BinaryOperator>(Op0))
      if (SI->getOpcode() == Instruction::Shl)
        if (Constant *ShOp = dyn_cast<Constant>(SI->getOperand(1)))
          return BinaryOperator::CreateMul(SI->getOperand(0),
                                           ConstantExpr::getShl(CI, ShOp));
    
    const APInt &Val = CI->getValue();
    if (Val.isPowerOf2()) {          // Replace X*(2^C) with X << C
      Constant *NewCst = ConstantInt::get(Op0->getType(), Val.logBase2());
      BinaryOperator *Shl = BinaryOperator::CreateShl(Op0, NewCst);
      if (I.hasNoSignedWrap()) Shl->setHasNoSignedWrap();
      if (I.hasNoUnsignedWrap()) Shl->setHasNoUnsignedWrap();
      return Shl;
    }
    
    // Canonicalize (X+C1)*CI -> X*CI+C1*CI.
    { Value *X; ConstantInt *C1;
      if (Op0->hasOneUse() &&
          match(Op0, m_Add(m_Value(X), m_ConstantInt(C1)))) {
        Value *Add = Builder->CreateMul(X, CI);
        return BinaryOperator::CreateAdd(Add, Builder->CreateMul(C1, CI));
      }
    }

    // (Y - X) * (-(2**n)) -> (X - Y) * (2**n), for positive nonzero n
    // (Y + const) * (-(2**n)) -> (-constY) * (2**n), for positive nonzero n
    // The "* (2**n)" thus becomes a potential shifting opportunity.
    {
      const APInt &   Val = CI->getValue();
      const APInt &PosVal = Val.abs();
      if (Val.isNegative() && PosVal.isPowerOf2()) {
        Value *X = 0, *Y = 0;
        if (Op0->hasOneUse()) {
          ConstantInt *C1;
          Value *Sub = 0;
          if (match(Op0, m_Sub(m_Value(Y), m_Value(X))))
            Sub = Builder->CreateSub(X, Y, "suba");
          else if (match(Op0, m_Add(m_Value(Y), m_ConstantInt(C1))))
            Sub = Builder->CreateSub(Builder->CreateNeg(C1), Y, "subc");
          if (Sub)
            return
              BinaryOperator::CreateMul(Sub,
                                        ConstantInt::get(Y->getType(), PosVal));
        }
      }
    }
  }
  
  // Simplify mul instructions with a constant RHS.
  if (isa<Constant>(Op1)) {    
    // Try to fold constant mul into select arguments.
    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
      if (Instruction *R = FoldOpIntoSelect(I, SI))
        return R;

    if (isa<PHINode>(Op0))
      if (Instruction *NV = FoldOpIntoPhi(I))
        return NV;
  }

  if (Value *Op0v = dyn_castNegVal(Op0))     // -X * -Y = X*Y
    if (Value *Op1v = dyn_castNegVal(Op1))
      return BinaryOperator::CreateMul(Op0v, Op1v);

  // (X / Y) *  Y = X - (X % Y)
  // (X / Y) * -Y = (X % Y) - X
  {
    Value *Op1C = Op1;
    BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0);
    if (!BO ||
        (BO->getOpcode() != Instruction::UDiv && 
         BO->getOpcode() != Instruction::SDiv)) {
      Op1C = Op0;
      BO = dyn_cast<BinaryOperator>(Op1);
    }
    Value *Neg = dyn_castNegVal(Op1C);
    if (BO && BO->hasOneUse() &&
        (BO->getOperand(1) == Op1C || BO->getOperand(1) == Neg) &&
        (BO->getOpcode() == Instruction::UDiv ||
         BO->getOpcode() == Instruction::SDiv)) {
      Value *Op0BO = BO->getOperand(0), *Op1BO = BO->getOperand(1);

      // If the division is exact, X % Y is zero, so we end up with X or -X.
      if (PossiblyExactOperator *SDiv = dyn_cast<PossiblyExactOperator>(BO))
//.........这里部分代码省略.........

//.........这里部分代码省略.........
      Op = Instruction::Add;
      break;
    case 1:
      Op = Instruction::Sub;
      break;
    case 2:
      Op = Instruction::Mul;
      break;
    case 3:
      Op = Instruction::SDiv;
      break;
    case 4:
      Op = Instruction::UDiv;
      break;
    case 5:
      Op = Instruction::SRem;
      break;
    case 6:
      Op = Instruction::URem;
      break;
    case 7:
      Op = Instruction::And;
      break;
    case 8:
      Op = Instruction::Or;
      break;
    case 9:
      Op = Instruction::Xor;
      break;
    }
    Value *L, *R;
    genLR(L, R, Budget, Width);
    Value *V = Builder->CreateBinOp(Op, L, R);
    if (!NoUB) {
      if ((Op == Instruction::Add || Op == Instruction::Sub ||
           Op == Instruction::Mul || Op == Instruction::Shl) &&
          Choose(2)) {
        BinaryOperator *B = cast<BinaryOperator>(V);
        B->setHasNoSignedWrap(true);
      }
      if ((Op == Instruction::Add || Op == Instruction::Sub ||
           Op == Instruction::Mul || Op == Instruction::Shl) &&
          Choose(2)) {
        BinaryOperator *B = cast<BinaryOperator>(V);
        B->setHasNoUnsignedWrap(true);
      }
      if ((Op == Instruction::UDiv || Op == Instruction::SDiv ||
           Op == Instruction::LShr || Op == Instruction::AShr) &&
          Choose(2)) {
        BinaryOperator *B = cast<BinaryOperator>(V);
        B->setIsExact(true);
      }
    }
    Vals.push_back(V);
    return V;
  }

  if (ConstOK && Choose(2)) {
    if (Verbose)
      errs() << "adding a const with width = " << Width
             << " and budget = " << Budget << "\n";
    if (OneConst) {
      return ConstantInt::get(*C, APInt(Width, 1));
    } else {
      int n = Choose((1 << Width) + 1);
      if (n == (1 << Width))
        return UndefValue::get(Type::getIntNTy(*C, Width));
      else
        return ConstantInt::get(*C, APInt(Width, n));
    }
  }

  if (Verbose)
    errs() << "using existing val with width = " << Width
           << " and budget = " << Budget << " and ArgOK = " << ArgOK << "\n";
  std::vector<Value *> Vs;
  for (auto &it : Vals)
    if (it->getType()->getPrimitiveSizeInBits() == Width)
      Vs.push_back(it);
  unsigned choices = Vs.size() + (ArgOK ? 1 : 0);
  if (choices == 0)
    exit(0);
  unsigned which = Choose(choices);
  if (which == Vs.size()) {
    Value *V = 0;
    for (auto it = F->arg_begin(); it != F->arg_end(); ++it) {
      if (UsedArgs.find(it) == UsedArgs.end() &&
          it->getType()->getPrimitiveSizeInBits() == Width) {
        UsedArgs.insert(it);
        V = it;
        Vals.push_back(V);
        break;
      }
    }
    ensure(V);
    return V;
  } else {
    return Vs.at(which);
  }
}

/// InsertPHITranslatedPointer - Insert a computation of the PHI translated
/// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
/// block.  All newly created instructions are added to the NewInsts list.
/// This returns null on failure.
///
Value *PHITransAddr::
InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
                           BasicBlock *PredBB, const DominatorTree &DT,
                           SmallVectorImpl<Instruction*> &NewInsts) {
  // See if we have a version of this value already available and dominating
  // PredBB.  If so, there is no need to insert a new instance of it.
  PHITransAddr Tmp(InVal, TD);
  if (!Tmp.PHITranslateValue(CurBB, PredBB, &DT))
    return Tmp.getAddr();

  // If we don't have an available version of this value, it must be an
  // instruction.
  Instruction *Inst = cast<Instruction>(InVal);
  
  // Handle bitcast of PHI translatable value.
  if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
    Value *OpVal = InsertPHITranslatedSubExpr(BC->getOperand(0),
                                              CurBB, PredBB, DT, NewInsts);
    if (OpVal == 0) return 0;
    
    // Otherwise insert a bitcast at the end of PredBB.
    BitCastInst *New = new BitCastInst(OpVal, InVal->getType(),
                                       InVal->getName()+".phi.trans.insert",
                                       PredBB->getTerminator());
    NewInsts.push_back(New);
    return New;
  }
  
  // Handle getelementptr with at least one PHI operand.
  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
    SmallVector<Value*, 8> GEPOps;
    BasicBlock *CurBB = GEP->getParent();
    for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
      Value *OpVal = InsertPHITranslatedSubExpr(GEP->getOperand(i),
                                                CurBB, PredBB, DT, NewInsts);
      if (OpVal == 0) return 0;
      GEPOps.push_back(OpVal);
    }
    
    GetElementPtrInst *Result = 
    GetElementPtrInst::Create(GEPOps[0], GEPOps.begin()+1, GEPOps.end(),
                              InVal->getName()+".phi.trans.insert",
                              PredBB->getTerminator());
    Result->setIsInBounds(GEP->isInBounds());
    NewInsts.push_back(Result);
    return Result;
  }
  
#if 0
  // FIXME: This code works, but it is unclear that we actually want to insert
  // a big chain of computation in order to make a value available in a block.
  // This needs to be evaluated carefully to consider its cost trade offs.
  
  // Handle add with a constant RHS.
  if (Inst->getOpcode() == Instruction::Add &&
      isa<ConstantInt>(Inst->getOperand(1))) {
    // PHI translate the LHS.
    Value *OpVal = InsertPHITranslatedSubExpr(Inst->getOperand(0),
                                              CurBB, PredBB, DT, NewInsts);
    if (OpVal == 0) return 0;
    
    BinaryOperator *Res = BinaryOperator::CreateAdd(OpVal, Inst->getOperand(1),
                                           InVal->getName()+".phi.trans.insert",
                                                    PredBB->getTerminator());
    Res->setHasNoSignedWrap(cast<BinaryOperator>(Inst)->hasNoSignedWrap());
    Res->setHasNoUnsignedWrap(cast<BinaryOperator>(Inst)->hasNoUnsignedWrap());
    NewInsts.push_back(Res);
    return Res;
  }
#endif
  
  return 0;
}

//.........这里部分代码省略.........
      if (AmtSum >= TypeBits) {
        if (I.getOpcode() != Instruction::AShr)
          return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
        AmtSum = TypeBits-1;  // Saturate to 31 for i32 ashr.
      }

      return BinaryOperator::Create(I.getOpcode(), X,
                                    ConstantInt::get(Ty, AmtSum));
    }

    if (ShiftAmt1 == ShiftAmt2) {
      // If we have ((X << C) >>u C), turn this into X & (-1 >>u C).
      if (I.getOpcode() == Instruction::LShr &&
          ShiftOp->getOpcode() == Instruction::Shl) {
        APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt1));
        return BinaryOperator::CreateAnd(X,
                                        ConstantInt::get(I.getContext(), Mask));
      }
    } else if (ShiftAmt1 < ShiftAmt2) {
      uint32_t ShiftDiff = ShiftAmt2-ShiftAmt1;

      // (X >>?,exact C1) << C2 --> X << (C2-C1)
      // The inexact version is deferred to DAGCombine so we don't hide shl
      // behind a bit mask.
      if (I.getOpcode() == Instruction::Shl &&
          ShiftOp->getOpcode() != Instruction::Shl &&
          ShiftOp->isExact()) {
        assert(ShiftOp->getOpcode() == Instruction::LShr ||
               ShiftOp->getOpcode() == Instruction::AShr);
        ConstantInt *ShiftDiffCst = ConstantInt::get(Ty, ShiftDiff);
        BinaryOperator *NewShl = BinaryOperator::Create(Instruction::Shl,
                                                        X, ShiftDiffCst);
        NewShl->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
        NewShl->setHasNoSignedWrap(I.hasNoSignedWrap());
        return NewShl;
      }

      // (X << C1) >>u C2  --> X >>u (C2-C1) & (-1 >> C2)
      if (I.getOpcode() == Instruction::LShr &&
          ShiftOp->getOpcode() == Instruction::Shl) {
        ConstantInt *ShiftDiffCst = ConstantInt::get(Ty, ShiftDiff);
        // (X <<nuw C1) >>u C2 --> X >>u (C2-C1)
        if (ShiftOp->hasNoUnsignedWrap()) {
          BinaryOperator *NewLShr = BinaryOperator::Create(Instruction::LShr,
                                                           X, ShiftDiffCst);
          NewLShr->setIsExact(I.isExact());
          return NewLShr;
        }
        Value *Shift = Builder->CreateLShr(X, ShiftDiffCst);

        APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
        return BinaryOperator::CreateAnd(Shift,
                                         ConstantInt::get(I.getContext(),Mask));
      }

      // We can't handle (X << C1) >>s C2, it shifts arbitrary bits in. However,
      // we can handle (X <<nsw C1) >>s C2 since it only shifts in sign bits.
      if (I.getOpcode() == Instruction::AShr &&
          ShiftOp->getOpcode() == Instruction::Shl) {
        if (ShiftOp->hasNoSignedWrap()) {
          // (X <<nsw C1) >>s C2 --> X >>s (C2-C1)
          ConstantInt *ShiftDiffCst = ConstantInt::get(Ty, ShiftDiff);
          BinaryOperator *NewAShr = BinaryOperator::Create(Instruction::AShr,
                                                           X, ShiftDiffCst);
          NewAShr->setIsExact(I.isExact());
          return NewAShr;

/// GetShiftedValue - When CanEvaluateShifted returned true for an expression,
/// this value inserts the new computation that produces the shifted value.
static Value *GetShiftedValue(Value *V, unsigned NumBits, bool isLeftShift,
                              InstCombiner &IC) {
  // We can always evaluate constants shifted.
  if (Constant *C = dyn_cast<Constant>(V)) {
    if (isLeftShift)
      V = IC.Builder->CreateShl(C, NumBits);
    else
      V = IC.Builder->CreateLShr(C, NumBits);
    // If we got a constantexpr back, try to simplify it with TD info.
    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
      V = ConstantFoldConstantExpression(CE, IC.getDataLayout(),
                                         IC.getTargetLibraryInfo());
    return V;
  }

  Instruction *I = cast<Instruction>(V);
  IC.Worklist.Add(I);

  switch (I->getOpcode()) {
  default: llvm_unreachable("Inconsistency with CanEvaluateShifted");
  case Instruction::And:
  case Instruction::Or:
  case Instruction::Xor:
    // Bitwise operators can all arbitrarily be arbitrarily evaluated shifted.
    I->setOperand(0, GetShiftedValue(I->getOperand(0), NumBits,isLeftShift,IC));
    I->setOperand(1, GetShiftedValue(I->getOperand(1), NumBits,isLeftShift,IC));
    return I;

  case Instruction::Shl: {
    BinaryOperator *BO = cast<BinaryOperator>(I);
    unsigned TypeWidth = BO->getType()->getScalarSizeInBits();

    // We only accept shifts-by-a-constant in CanEvaluateShifted.
    ConstantInt *CI = cast<ConstantInt>(BO->getOperand(1));

    // We can always fold shl(c1)+shl(c2) -> shl(c1+c2).
    if (isLeftShift) {
      // If this is oversized composite shift, then unsigned shifts get 0.
      unsigned NewShAmt = NumBits+CI->getZExtValue();
      if (NewShAmt >= TypeWidth)
        return Constant::getNullValue(I->getType());

      BO->setOperand(1, ConstantInt::get(BO->getType(), NewShAmt));
      BO->setHasNoUnsignedWrap(false);
      BO->setHasNoSignedWrap(false);
      return I;
    }

    // We turn shl(c)+lshr(c) -> and(c2) if the input doesn't already have
    // zeros.
    if (CI->getValue() == NumBits) {
      APInt Mask(APInt::getLowBitsSet(TypeWidth, TypeWidth - NumBits));
      V = IC.Builder->CreateAnd(BO->getOperand(0),
                                ConstantInt::get(BO->getContext(), Mask));
      if (Instruction *VI = dyn_cast<Instruction>(V)) {
        VI->moveBefore(BO);
        VI->takeName(BO);
      }
      return V;
    }

    // We turn shl(c1)+shr(c2) -> shl(c3)+and(c4), but only when we know that
    // the and won't be needed.
    assert(CI->getZExtValue() > NumBits);
    BO->setOperand(1, ConstantInt::get(BO->getType(),
                                       CI->getZExtValue() - NumBits));
    BO->setHasNoUnsignedWrap(false);
    BO->setHasNoSignedWrap(false);
    return BO;
  }
  case Instruction::LShr: {
    BinaryOperator *BO = cast<BinaryOperator>(I);
    unsigned TypeWidth = BO->getType()->getScalarSizeInBits();
    // We only accept shifts-by-a-constant in CanEvaluateShifted.
    ConstantInt *CI = cast<ConstantInt>(BO->getOperand(1));

    // We can always fold lshr(c1)+lshr(c2) -> lshr(c1+c2).
    if (!isLeftShift) {
      // If this is oversized composite shift, then unsigned shifts get 0.
      unsigned NewShAmt = NumBits+CI->getZExtValue();
      if (NewShAmt >= TypeWidth)
        return Constant::getNullValue(BO->getType());

      BO->setOperand(1, ConstantInt::get(BO->getType(), NewShAmt));
      BO->setIsExact(false);
      return I;
    }

    // We turn lshr(c)+shl(c) -> and(c2) if the input doesn't already have
    // zeros.
    if (CI->getValue() == NumBits) {
      APInt Mask(APInt::getHighBitsSet(TypeWidth, TypeWidth - NumBits));
      V = IC.Builder->CreateAnd(I->getOperand(0),
                                ConstantInt::get(BO->getContext(), Mask));
      if (Instruction *VI = dyn_cast<Instruction>(V)) {
        VI->moveBefore(I);
        VI->takeName(I);
      }
//.........这里部分代码省略.........

/// InsertPHITranslatedPointer - Insert a computation of the PHI translated
/// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
/// block.  All newly created instructions are added to the NewInsts list.
/// This returns null on failure.
///
Value *PHITransAddr::
InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
                           BasicBlock *PredBB, const DominatorTree &DT,
                           SmallVectorImpl<Instruction*> &NewInsts) {
  // See if we have a version of this value already available and dominating
  // PredBB.  If so, there is no need to insert a new instance of it.
  PHITransAddr Tmp(InVal, DL, AC);
  if (!Tmp.PHITranslateValue(CurBB, PredBB, &DT, /*MustDominate=*/true))
    return Tmp.getAddr();

  // We don't need to PHI translate values which aren't instructions.
  auto *Inst = dyn_cast<Instruction>(InVal);
  if (!Inst)
    return nullptr;

  // Handle cast of PHI translatable value.
  if (CastInst *Cast = dyn_cast<CastInst>(Inst)) {
    if (!isSafeToSpeculativelyExecute(Cast)) return nullptr;
    Value *OpVal = InsertPHITranslatedSubExpr(Cast->getOperand(0),
                                              CurBB, PredBB, DT, NewInsts);
    if (!OpVal) return nullptr;

    // Otherwise insert a cast at the end of PredBB.
    CastInst *New = CastInst::Create(Cast->getOpcode(), OpVal, InVal->getType(),
                                     InVal->getName() + ".phi.trans.insert",
                                     PredBB->getTerminator());
    New->setDebugLoc(Inst->getDebugLoc());
    NewInsts.push_back(New);
    return New;
  }

  // Handle getelementptr with at least one PHI operand.
  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
    SmallVector<Value*, 8> GEPOps;
    BasicBlock *CurBB = GEP->getParent();
    for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
      Value *OpVal = InsertPHITranslatedSubExpr(GEP->getOperand(i),
                                                CurBB, PredBB, DT, NewInsts);
      if (!OpVal) return nullptr;
      GEPOps.push_back(OpVal);
    }

    GetElementPtrInst *Result = GetElementPtrInst::Create(
        GEP->getSourceElementType(), GEPOps[0], makeArrayRef(GEPOps).slice(1),
        InVal->getName() + ".phi.trans.insert", PredBB->getTerminator());
    Result->setDebugLoc(Inst->getDebugLoc());
    Result->setIsInBounds(GEP->isInBounds());
    NewInsts.push_back(Result);
    return Result;
  }

#if 0
  // FIXME: This code works, but it is unclear that we actually want to insert
  // a big chain of computation in order to make a value available in a block.
  // This needs to be evaluated carefully to consider its cost trade offs.

  // Handle add with a constant RHS.
  if (Inst->getOpcode() == Instruction::Add &&
      isa<ConstantInt>(Inst->getOperand(1))) {
    // PHI translate the LHS.
    Value *OpVal = InsertPHITranslatedSubExpr(Inst->getOperand(0),
                                              CurBB, PredBB, DT, NewInsts);
    if (OpVal == 0) return 0;

    BinaryOperator *Res = BinaryOperator::CreateAdd(OpVal, Inst->getOperand(1),
                                           InVal->getName()+".phi.trans.insert",
                                                    PredBB->getTerminator());
    Res->setHasNoSignedWrap(cast<BinaryOperator>(Inst)->hasNoSignedWrap());
    Res->setHasNoUnsignedWrap(cast<BinaryOperator>(Inst)->hasNoUnsignedWrap());
    NewInsts.push_back(Res);
    return Res;
  }
#endif

  return nullptr;
}