[ValueTracking] Convert most of the calls to computeKnownBits to use the version that returns the KnownBits obje

[craig.topper]

Summary

This continues the changes started when computeSignBit was replaced with this new version of computeKnowBits.

[RKSimon]

LGTM - the KnownBits changes and the OptimizationRemarkEmitter arg change should be committed separately.

include/llvm/Analysis/ValueTracking.h

64

This looks like it should be committed separately but I don't know what test coverage is possible.

[davide]

Agree with Simon, this needs to be split in two patches.

include/llvm/Analysis/ValueTracking.h

void computeKnownBits(const Value *V, KnownBits &Known,
                         AssumptionCache *AC = nullptr,
                         const Instruction *CxtI = nullptr,
                         const DominatorTree *DT = nullptr,
                         OptimizationRemarkEmitter *ORE = nullptr);
   /// Returns the known bits rather than passing by reference.
   KnownBits computeKnownBits(const Value *V, const DataLayout &DL,
                              unsigned Depth = 0, AssumptionCache *AC = nullptr,
                              const Instruction *CxtI = nullptr,
-                             const DominatorTree *DT = nullptr);
+                             const DominatorTree *DT = nullptr,
+                             OptimizationRemarkEmitter *ORE = nullptr);
   /// Compute known bits from the range metadata.
   /// \p KnownZero the set of bits that are known to be zero
   /// \p KnownOne the set of bits that are known to be one
   void computeKnownBitsFromRangeMetadata(const MDNode &Ranges,
                                          KnownBits &Known);
   /// Return true if LHS and RHS have no common bits set.
   bool haveNoCommonBitsSet(const Value *LHS, const Value *RHS,
                            const DataLayout &DL,

lib/Analysis/ConstantFolding.cpp

Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0, Constant *Op1,
                                     const DataLayout &DL) {
   // SROA
 
   // Fold (and 0xffffffff00000000, (shl x, 32)) -> shl.
   // Fold (lshr (or X, Y), 32) -> (lshr [X/Y], 32) if one doesn't contribute
   // bits.
 
   if (Opc == Instruction::And) {
-    unsigned BitWidth = DL.getTypeSizeInBits(Op0->getType()->getScalarType());
-    KnownBits Known0(BitWidth);
-    KnownBits Known1(BitWidth);
-    computeKnownBits(Op0, Known0, DL);
-    computeKnownBits(Op1, Known1, DL);
+    KnownBits Known0 = computeKnownBits(Op0, DL);
+    KnownBits Known1 = computeKnownBits(Op1, DL);
     if ((Known1.One | Known0.Zero).isAllOnesValue()) {
       // All the bits of Op0 that the 'and' could be masking are already zero.
       return Op0;
     }
     if ((Known0.One | Known1.Zero).isAllOnesValue()) {
       // All the bits of Op1 that the 'and' could be masking are already zero.
       return Op1;
     }

lib/Analysis/InstructionSimplify.cpp

if (Op0 == Op1)
     return Constant::getNullValue(Op0->getType());
 
   // Is this a negation?
   if (match(Op0, m_Zero())) {
     // 0 - X -> 0 if the sub is NUW.
     if (isNUW)
       return Op0;
 
-    unsigned BitWidth = Op1->getType()->getScalarSizeInBits();
-    KnownBits Known(BitWidth);
-    computeKnownBits(Op1, Known, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
+    KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
     if (Known.Zero.isMaxSignedValue()) {
       // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
       // Op1 must be 0 because negating the minimum signed value is undefined.
       if (isNSW)
         return Op0;
 
       // 0 - X -> X if X is 0 or the minimum signed value.
       return Op1;
static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0,
   // If the operation is with the result of a phi instruction, check whether
   // operating on all incoming values of the phi always yields the same value.
   if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
     if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
       return V;
 
   // If any bits in the shift amount make that value greater than or equal to
   // the number of bits in the type, the shift is undefined.
-  unsigned BitWidth = Op1->getType()->getScalarSizeInBits();
-  KnownBits Known(BitWidth);
-  computeKnownBits(Op1, Known, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
-  if (Known.One.getLimitedValue() >= BitWidth)
+  KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
+  if (Known.One.getLimitedValue() >= Known.getBitWidth())
     return UndefValue::get(Op0->getType());
 
   // If all valid bits in the shift amount are known zero, the first operand is
   // unchanged.
-  unsigned NumValidShiftBits = Log2_32_Ceil(BitWidth);
+  unsigned NumValidShiftBits = Log2_32_Ceil(Known.getBitWidth());
   if (Known.countMinTrailingZeros() >= NumValidShiftBits)
     return Op0;
 
   return nullptr;
 }
 
 /// \brief Given operands for an Shl, LShr or AShr, see if we can
 /// fold the result.  If not, this returns null.
static Value *SimplifyRightShift(Instruction::BinaryOps Opcode, Value *Op0,
 
   // undef >> X -> 0
   // undef >> X -> undef (if it's exact)
   if (match(Op0, m_Undef()))
     return isExact ? Op0 : Constant::getNullValue(Op0->getType());
 
   // The low bit cannot be shifted out of an exact shift if it is set.
   if (isExact) {
-    unsigned BitWidth = Op0->getType()->getScalarSizeInBits();
-    KnownBits Op0Known(BitWidth);
-    computeKnownBits(Op0, Op0Known, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
+    KnownBits Op0Known = computeKnownBits(Op0, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
     if (Op0Known.One[0])
       return Op0;
   }
 
   return nullptr;
 }
 
 /// Given operands for an Shl, see if we can fold the result.
if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) {
     }
   }
 
   // If a bit is known to be zero for A and known to be one for B,
   // then A and B cannot be equal.
   if (ICmpInst::isEquality(Pred)) {
     const APInt *RHSVal;
     if (match(RHS, m_APInt(RHSVal))) {
-      unsigned BitWidth = RHSVal->getBitWidth();
-      KnownBits LHSKnown(BitWidth);
-      computeKnownBits(LHS, LHSKnown, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
+      KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT);
       if (LHSKnown.Zero.intersects(*RHSVal) ||
           !LHSKnown.One.isSubsetOf(*RHSVal))
         return Pred == ICmpInst::ICMP_EQ ? ConstantInt::getFalse(ITy)
                                          : ConstantInt::getTrue(ITy);
     }
   }
 
   // If the comparison is with the result of a select instruction, check whether
case Instruction::Alloca:
     // No simplifications for Alloca and it can't be constant folded.
     Result = nullptr;
     break;
   }
 
   // In general, it is possible for computeKnownBits to determine all bits in a
   // value even when the operands are not all constants.
   if (!Result && I->getType()->isIntOrIntVectorTy()) {
-    unsigned BitWidth = I->getType()->getScalarSizeInBits();
-    KnownBits Known(BitWidth);
-    computeKnownBits(I, Known, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE);
+    KnownBits Known = computeKnownBits(I, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE);
     if (Known.isConstant())
       Result = ConstantInt::get(I->getType(), Known.getConstant());
   }
 
   /// If called on unreachable code, the above logic may report that the
   /// instruction simplified to itself.  Make life easier for users by
   /// detecting that case here, returning a safe value instead.
   return Result == I ? UndefValue::get(I->getType()) : Result;

lib/Analysis/Lint.cpp

 static bool isZero(Value *V, const DataLayout &DL, DominatorTree *DT,
                    AssumptionCache *AC) {
   // Assume undef could be zero.
   if (isa<UndefValue>(V))
     return true;
 
   VectorType *VecTy = dyn_cast<VectorType>(V->getType());
   if (!VecTy) {
-    unsigned BitWidth = V->getType()->getIntegerBitWidth();
-    KnownBits Known(BitWidth);
-    computeKnownBits(V, Known, DL, 0, AC, dyn_cast<Instruction>(V), DT);
+    KnownBits Known = computeKnownBits(V, DL, 0, AC, dyn_cast<Instruction>(V), DT);
     return Known.isZero();
   }
 
   // Per-component check doesn't work with zeroinitializer
   Constant *C = dyn_cast<Constant>(V);
   if (!C)
     return false;
 
   if (C->isZeroValue())
     return true;
 
   // For a vector, KnownZero will only be true if all values are zero, so check
   // this per component
-  unsigned BitWidth = VecTy->getElementType()->getIntegerBitWidth();
   for (unsigned I = 0, N = VecTy->getNumElements(); I != N; ++I) {
     Constant *Elem = C->getAggregateElement(I);
     if (isa<UndefValue>(Elem))
       return true;
 
-    KnownBits Known(BitWidth);
-    computeKnownBits(Elem, Known, DL);
+    KnownBits Known = computeKnownBits(Elem, DL);
     if (Known.isZero())
       return true;
   }
 
   return false;
 }
 
 void Lint::visitSDiv(BinaryOperator &I) {

lib/Analysis/ScalarEvolution.cpp

if (const SCEVUMaxExpr *M = dyn_cast<SCEVUMaxExpr>(S)) {
     uint32_t MinOpRes = GetMinTrailingZeros(M->getOperand(0));
     for (unsigned i = 1, e = M->getNumOperands(); MinOpRes && i != e; ++i)
       MinOpRes = std::min(MinOpRes, GetMinTrailingZeros(M->getOperand(i)));
     return MinOpRes;
   }
 
   if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
     // For a SCEVUnknown, ask ValueTracking.
-    unsigned BitWidth = getTypeSizeInBits(U->getType());
-    KnownBits Known(BitWidth);
-    computeKnownBits(U->getValue(), Known, getDataLayout(), 0, &AC,
-                     nullptr, &DT);
+    KnownBits Known = computeKnownBits(U->getValue(), getDataLayout(), 0, &AC, nullptr, &DT);
     return Known.countMinTrailingZeros();
   }
 
   // SCEVUDivExpr
   return 0;
 }
 
 uint32_t ScalarEvolution::GetMinTrailingZeros(const SCEV *S) {
if (MDRange.hasValue())
       ConservativeResult = ConservativeResult.intersectWith(MDRange.getValue());
 
     // Split here to avoid paying the compile-time cost of calling both
     // computeKnownBits and ComputeNumSignBits.  This restriction can be lifted
     // if needed.
     const DataLayout &DL = getDataLayout();
     if (SignHint == ScalarEvolution::HINT_RANGE_UNSIGNED) {
       // For a SCEVUnknown, ask ValueTracking.
-      KnownBits Known(BitWidth);
-      computeKnownBits(U->getValue(), Known, DL, 0, &AC, nullptr, &DT);
+      KnownBits Known = computeKnownBits(U->getValue(), DL, 0, &AC, nullptr, &DT);
       if (Known.One != ~Known.Zero + 1)
         ConservativeResult =
             ConservativeResult.intersectWith(ConstantRange(Known.One,
                                                            ~Known.Zero + 1));
     } else {
       assert(SignHint == ScalarEvolution::HINT_RANGE_SIGNED &&
              "generalize as needed!");
       unsigned NS = ComputeNumSignBits(U->getValue(), DL, 0, &AC, nullptr, &DT);

lib/Analysis/ValueTracking.cpp

 }
 
 static KnownBits computeKnownBits(const Value *V, unsigned Depth,
                                   const Query &Q);
 
 KnownBits llvm::computeKnownBits(const Value *V, const DataLayout &DL,
                                  unsigned Depth, AssumptionCache *AC,
                                  const Instruction *CxtI,
-                                 const DominatorTree *DT) {
-  return ::computeKnownBits(V, Depth, Query(DL, AC, safeCxtI(V, CxtI), DT));
+                                 const DominatorTree *DT,
+                                 OptimizationRemarkEmitter *ORE) {
+  return ::computeKnownBits(V, Depth, Query(DL, AC, safeCxtI(V, CxtI), DT, ORE));
 }
 
 bool llvm::haveNoCommonBitsSet(const Value *LHS, const Value *RHS,
                                const DataLayout &DL,
                                AssumptionCache *AC, const Instruction *CxtI,
                                const DominatorTree *DT) {
   assert(LHS->getType() == RHS->getType() &&
          "LHS and RHS should have the same type");

lib/Transforms/InstCombine/InstCombineAddSub.cpp

bool InstCombiner::willNotOverflowSignedSub(const Value *LHS,
                                             const Value *RHS,
                                             const Instruction &CxtI) const {
   // If LHS and RHS each have at least two sign bits, the subtraction
   // cannot overflow.
   if (ComputeNumSignBits(LHS, 0, &CxtI) > 1 &&
       ComputeNumSignBits(RHS, 0, &CxtI) > 1)
     return true;
 
-  unsigned BitWidth = LHS->getType()->getScalarSizeInBits();
-  KnownBits LHSKnown(BitWidth);
-  computeKnownBits(LHS, LHSKnown, 0, &CxtI);
+  KnownBits LHSKnown = computeKnownBits(LHS, 0, &CxtI);
 
-  KnownBits RHSKnown(BitWidth);
-  computeKnownBits(RHS, RHSKnown, 0, &CxtI);
+  KnownBits RHSKnown = computeKnownBits(RHS, 0, &CxtI);
 
   // Subtraction of two 2's complement numbers having identical signs will
   // never overflow.
   if ((LHSKnown.isNegative() && RHSKnown.isNegative()) ||
       (LHSKnown.isNonNegative() && RHSKnown.isNonNegative()))
     return true;
 
   // TODO: implement logic similar to checkRippleForAdd
if (match(LHS, m_Xor(m_Value(XorLHS), m_ConstantInt(XorRHS)))) {
         Constant *ShAmt = ConstantInt::get(I.getType(), ExtendAmt);
         Value *NewShl = Builder->CreateShl(XorLHS, ShAmt, "sext");
         return BinaryOperator::CreateAShr(NewShl, ShAmt);
       }
 
       // If this is a xor that was canonicalized from a sub, turn it back into
       // a sub and fuse this add with it.
       if (LHS->hasOneUse() && (XorRHS->getValue()+1).isPowerOf2()) {
-        IntegerType *IT = cast<IntegerType>(I.getType());
-        KnownBits LHSKnown(IT->getBitWidth());
-        computeKnownBits(XorLHS, LHSKnown, 0, &I);
+        KnownBits LHSKnown = computeKnownBits(XorLHS, 0, &I);
         if ((XorRHS->getValue() | LHSKnown.Zero).isAllOnesValue())
           return BinaryOperator::CreateSub(ConstantExpr::getAdd(XorRHS, CI),
                                            XorLHS);
       }
       // (X + signmask) + C could have gotten canonicalized to (X^signmask) + C,
       // transform them into (X + (signmask ^ C))
       if (XorRHS->getValue().isSignMask())
         return BinaryOperator::CreateAdd(XorLHS,
if (*Op0C == 0) {
         Value *ShAmtOp = cast<Instruction>(Op1)->getOperand(1);
         return BinaryOperator::CreateLShr(X, ShAmtOp);
       }
     }
 
     // Turn this into a xor if LHS is 2^n-1 and the remaining bits are known
     // zero.
     if (Op0C->isMask()) {
-      KnownBits RHSKnown(BitWidth);
-      computeKnownBits(Op1, RHSKnown, 0, &I);
+      KnownBits RHSKnown = computeKnownBits(Op1, 0, &I);
       if ((*Op0C | RHSKnown.Zero).isAllOnesValue())
         return BinaryOperator::CreateXor(Op1, Op0);
     }
   }
 
   {
     Value *Y;
     // X-(X+Y) == -Y    X-(Y+X) == -Y

lib/Transforms/InstCombine/InstCombineCalls.cpp

assert((II.getIntrinsicID() == Intrinsic::cttz ||
           II.getIntrinsicID() == Intrinsic::ctlz) &&
          "Expected cttz or ctlz intrinsic");
   Value *Op0 = II.getArgOperand(0);
   // FIXME: Try to simplify vectors of integers.
   auto *IT = dyn_cast<IntegerType>(Op0->getType());
   if (!IT)
     return nullptr;
 
-  unsigned BitWidth = IT->getBitWidth();
-  KnownBits Known(BitWidth);
-  IC.computeKnownBits(Op0, Known, 0, &II);
+  KnownBits Known = IC.computeKnownBits(Op0, 0, &II);
 
   // Create a mask for bits above (ctlz) or below (cttz) the first known one.
   bool IsTZ = II.getIntrinsicID() == Intrinsic::cttz;
   unsigned PossibleZeros = IsTZ ? Known.countMaxTrailingZeros()
                                 : Known.countMaxLeadingZeros();
   unsigned DefiniteZeros = IsTZ ? Known.countMinTrailingZeros()
                                 : Known.countMinLeadingZeros();
 

lib/Transforms/InstCombine/InstCombineCasts.cpp

if (ConstantInt *Op1C = dyn_cast<ConstantInt>(ICI->getOperand(1))) {
     // zext (X != 0) to i32 --> X        iff X has only the low bit set.
     // zext (X != 0) to i32 --> X>>1     iff X has only the 2nd bit set.
     // zext (X != 1) to i32 --> X^1      iff X has only the low bit set.
     // zext (X != 2) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
     if ((Op1CV == 0 || Op1CV.isPowerOf2()) &&
         // This only works for EQ and NE
         ICI->isEquality()) {
       // If Op1C some other power of two, convert:
-      KnownBits Known(Op1C->getType()->getBitWidth());
-      computeKnownBits(ICI->getOperand(0), Known, 0, &CI);
+      KnownBits Known = computeKnownBits(ICI->getOperand(0), 0, &CI);
 
       APInt KnownZeroMask(~Known.Zero);
       if (KnownZeroMask.isPowerOf2()) { // Exactly 1 possible 1?
         if (!DoTransform) return ICI;
 
         bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
         if (Op1CV != 0 && (Op1CV != KnownZeroMask)) {
           // (X&4) == 2 --> false
if (ConstantInt *Op1C = dyn_cast<ConstantInt>(ICI->getOperand(1))) {
     }
   }
 
   // icmp ne A, B is equal to xor A, B when A and B only really have one bit.
   // It is also profitable to transform icmp eq into not(xor(A, B)) because that
   // may lead to additional simplifications.
   if (ICI->isEquality() && CI.getType() == ICI->getOperand(0)->getType()) {
     if (IntegerType *ITy = dyn_cast<IntegerType>(CI.getType())) {
-      uint32_t BitWidth = ITy->getBitWidth();
       Value *LHS = ICI->getOperand(0);
       Value *RHS = ICI->getOperand(1);
 
-      KnownBits KnownLHS(BitWidth);
-      KnownBits KnownRHS(BitWidth);
-      computeKnownBits(LHS, KnownLHS, 0, &CI);
-      computeKnownBits(RHS, KnownRHS, 0, &CI);
+      KnownBits KnownLHS = computeKnownBits(LHS, 0, &CI);
+      KnownBits KnownRHS = computeKnownBits(RHS, 0, &CI);
 
       if (KnownLHS.Zero == KnownRHS.Zero && KnownLHS.One == KnownRHS.One) {
         APInt KnownBits = KnownLHS.Zero | KnownLHS.One;
         APInt UnknownBit = ~KnownBits;
         if (UnknownBit.countPopulation() == 1) {
           if (!DoTransform) return ICI;
 
           Value *Result = Builder->CreateXor(LHS, RHS);
Instruction *InstCombiner::transformSExtICmp(ICmpInst *ICI, Instruction &CI) {
   }
 
   if (ConstantInt *Op1C = dyn_cast<ConstantInt>(Op1)) {
     // If we know that only one bit of the LHS of the icmp can be set and we
     // have an equality comparison with zero or a power of 2, we can transform
     // the icmp and sext into bitwise/integer operations.
     if (ICI->hasOneUse() &&
         ICI->isEquality() && (Op1C->isZero() || Op1C->getValue().isPowerOf2())){
-      unsigned BitWidth = Op1C->getType()->getBitWidth();
-      KnownBits Known(BitWidth);
-      computeKnownBits(Op0, Known, 0, &CI);
+      KnownBits Known = computeKnownBits(Op0, 0, &CI);
 
       APInt KnownZeroMask(~Known.Zero);
       if (KnownZeroMask.isPowerOf2()) {
         Value *In = ICI->getOperand(0);
 
         // If the icmp tests for a known zero bit we can constant fold it.
         if (!Op1C->isZero() && Op1C->getValue() != KnownZeroMask) {
           Value *V = Pred == ICmpInst::ICMP_NE ?
if (ICI->hasOneUse() &&
           unsigned ShiftAmt = KnownZeroMask.countLeadingZeros();
           // Perform a left shift to place the desired bit in the MSB.
           if (ShiftAmt)
             In = Builder->CreateShl(In,
                                     ConstantInt::get(In->getType(), ShiftAmt));
 
           // Distribute the bit over the whole bit width.
           In = Builder->CreateAShr(In, ConstantInt::get(In->getType(),
-                                                        BitWidth - 1), "sext");
+                                      KnownZeroMask.getBitWidth() - 1), "sext");
         }
 
         if (CI.getType() == In->getType())
           return replaceInstUsesWith(CI, In);
         return CastInst::CreateIntegerCast(In, CI.getType(), true/*SExt*/);
       }
     }
   }

lib/Transforms/InstCombine/InstCombineCompares.cpp

if (Pred == ICmpInst::ICMP_SLT && match(X, m_Signum(m_Value(V))))
                           ConstantInt::get(V->getType(), 1));
   }
 
   if (Cmp.isEquality() && Trunc->hasOneUse()) {
     // Simplify icmp eq (trunc x to i8), 42 -> icmp eq x, 42|highbits if all
     // of the high bits truncated out of x are known.
     unsigned DstBits = Trunc->getType()->getScalarSizeInBits(),
              SrcBits = X->getType()->getScalarSizeInBits();
-    KnownBits Known(SrcBits);
-    computeKnownBits(X, Known, 0, &Cmp);
+    KnownBits Known = computeKnownBits(X, 0, &Cmp);
 
     // If all the high bits are known, we can do this xform.
     if ((Known.Zero | Known.One).countLeadingOnes() >= SrcBits - DstBits) {
       // Pull in the high bits from known-ones set.
       APInt NewRHS = C->zext(SrcBits);
       NewRHS |= Known.One & APInt::getHighBitsSet(SrcBits, SrcBits - DstBits);
       return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), NewRHS));
     }

lib/Transforms/InstCombine/InstructionCombining.cpp

Instruction *InstCombiner::visitReturnInst(ReturnInst &RI) {
 
   Value *ResultOp = RI.getOperand(0);
   Type *VTy = ResultOp->getType();
   if (!VTy->isIntegerTy())
     return nullptr;
 
   // There might be assume intrinsics dominating this return that completely
   // determine the value. If so, constant fold it.
-  KnownBits Known(VTy->getPrimitiveSizeInBits());
-  computeKnownBits(ResultOp, Known, 0, &RI);
+  KnownBits Known = computeKnownBits(ResultOp, 0, &RI);
   if (Known.isConstant())
     RI.setOperand(0, Constant::getIntegerValue(VTy, Known.getConstant()));
 
   return nullptr;
 }
 
 Instruction *InstCombiner::visitBranchInst(BranchInst &BI) {
   // Change br (not X), label True, label False to: br X, label False, True
for (auto Case : SI.cases()) {
       assert(isa<ConstantInt>(NewCase) &&
              "Result of expression should be constant");
       Case.setValue(cast<ConstantInt>(NewCase));
     }
     SI.setCondition(Op0);
     return &SI;
   }
 
-  unsigned BitWidth = cast<IntegerType>(Cond->getType())->getBitWidth();
-  KnownBits Known(BitWidth);
-  computeKnownBits(Cond, Known, 0, &SI);
+  KnownBits Known = computeKnownBits(Cond, 0, &SI);
   unsigned LeadingKnownZeros = Known.countMinLeadingZeros();
   unsigned LeadingKnownOnes = Known.countMinLeadingOnes();
 
   // Compute the number of leading bits we can ignore.
   // TODO: A better way to determine this would use ComputeNumSignBits().
   for (auto &C : SI.cases()) {
     LeadingKnownZeros = std::min(
         LeadingKnownZeros, C.getCaseValue()->getValue().countLeadingZeros());
     LeadingKnownOnes = std::min(
         LeadingKnownOnes, C.getCaseValue()->getValue().countLeadingOnes());
   }
 
-  unsigned NewWidth = BitWidth - std::max(LeadingKnownZeros, LeadingKnownOnes);
+  unsigned NewWidth = Known.getBitWidth() - std::max(LeadingKnownZeros, LeadingKnownOnes);
 
   // Shrink the condition operand if the new type is smaller than the old type.
   // This may produce a non-standard type for the switch, but that's ok because
   // the backend should extend back to a legal type for the target.
-  if (NewWidth > 0 && NewWidth < BitWidth) {
+  if (NewWidth > 0 && NewWidth < Known.getBitWidth()) {
     IntegerType *Ty = IntegerType::get(SI.getContext(), NewWidth);
     Builder->SetInsertPoint(&SI);
     Value *NewCond = Builder->CreateTrunc(Cond, Ty, "trunc");
     SI.setCondition(NewCond);
 
     for (auto Case : SI.cases()) {
       APInt TruncatedCase = Case.getCaseValue()->getValue().trunc(NewWidth);
       Case.setValue(ConstantInt::get(SI.getContext(), TruncatedCase));
if (!I->use_empty() &&
         continue;
       }
     }
 
     // In general, it is possible for computeKnownBits to determine all bits in
     // a value even when the operands are not all constants.
     Type *Ty = I->getType();
     if (ExpensiveCombines && !I->use_empty() && Ty->isIntOrIntVectorTy()) {
-      unsigned BitWidth = Ty->getScalarSizeInBits();
-      KnownBits Known(BitWidth);
-      computeKnownBits(I, Known, /*Depth*/0, I);
+      KnownBits Known = computeKnownBits(I, /*Depth*/0, I);
       if (Known.isConstant()) {
         Constant *C = ConstantInt::get(Ty, Known.getConstant());
         DEBUG(dbgs() << "IC: ConstFold (all bits known) to: " << *C <<
                         " from: " << *I << '\n');
 
         // Add operands to the worklist.
         replaceInstUsesWith(*I, C);
         ++NumConstProp;

lib/Transforms/Scalar/GuardWidening.cpp

#endif
 
     if (match(Check.getBase(), m_Add(m_Value(OpLHS), m_ConstantInt(OpRHS)))) {
       Check.setBase(OpLHS);
       APInt NewOffset = Check.getOffsetValue() + OpRHS->getValue();
       Check.setOffset(ConstantInt::get(Ctx, NewOffset));
       Changed = true;
     } else if (match(Check.getBase(),
                      m_Or(m_Value(OpLHS), m_ConstantInt(OpRHS)))) {
-      unsigned BitWidth = OpLHS->getType()->getScalarSizeInBits();
-      KnownBits Known(BitWidth);
-      computeKnownBits(OpLHS, Known, DL);
+      KnownBits Known = computeKnownBits(OpLHS, DL);
       if ((OpRHS->getValue() & Known.Zero) == OpRHS->getValue()) {
         Check.setBase(OpLHS);
         APInt NewOffset = Check.getOffsetValue() + OpRHS->getValue();
         Check.setOffset(ConstantInt::get(Ctx, NewOffset));
         Changed = true;
       }
     }
   } while (Changed);

lib/Transforms/Utils/Local.cpp

 
 unsigned llvm::getOrEnforceKnownAlignment(Value *V, unsigned PrefAlign,
                                           const DataLayout &DL,
                                           const Instruction *CxtI,
                                           AssumptionCache *AC,
                                           const DominatorTree *DT) {
   assert(V->getType()->isPointerTy() &&
          "getOrEnforceKnownAlignment expects a pointer!");
-  unsigned BitWidth = DL.getPointerTypeSizeInBits(V->getType());
 
-  KnownBits Known(BitWidth);
-  computeKnownBits(V, Known, DL, 0, AC, CxtI, DT);
+  KnownBits Known = computeKnownBits(V, DL, 0, AC, CxtI, DT);
   unsigned TrailZ = Known.countMinTrailingZeros();
 
   // Avoid trouble with ridiculously large TrailZ values, such as
   // those computed from a null pointer.
   TrailZ = std::min(TrailZ, unsigned(sizeof(unsigned) * CHAR_BIT - 1));
 
-  unsigned Align = 1u << std::min(BitWidth - 1, TrailZ);
+  unsigned Align = 1u << std::min(Known.getBitWidth() - 1, TrailZ);
 
   // LLVM doesn't support alignments larger than this currently.
   Align = std::min(Align, +Value::MaximumAlignment);
 
   if (PrefAlign > Align)
     Align = enforceKnownAlignment(V, Align, PrefAlign, DL);
 
   // We don't need to make any adjustment.

lib/Transforms/Utils/SimplifyCFG.cpp

 }
 
 /// Compute masked bits for the condition of a switch
 /// and use it to remove dead cases.
 static bool EliminateDeadSwitchCases(SwitchInst *SI, AssumptionCache *AC,
                                      const DataLayout &DL) {
   Value *Cond = SI->getCondition();
   unsigned Bits = Cond->getType()->getIntegerBitWidth();
-  KnownBits Known(Bits);
-  computeKnownBits(Cond, Known, DL, 0, AC, SI);
+  KnownBits Known = computeKnownBits(Cond, DL, 0, AC, SI);
 
   // We can also eliminate cases by determining that their values are outside of
   // the limited range of the condition based on how many significant (non-sign)
   // bits are in the condition value.
   unsigned ExtraSignBits = ComputeNumSignBits(Cond, DL, 0, AC, SI) - 1;
   unsigned MaxSignificantBitsInCond = Bits - ExtraSignBits;
 
   // Gather dead cases.

lib/Transforms/Utils/SimplifyLibCalls.cpp

if (getConstantDataArrayInfo(GEP->getOperand(0), Slice, CharSize)) {
         }
         // If the string does not have '\0', leave it to strlen to compute
         // its length.
         if (NullTermIdx == ~((uint64_t)0))
           return nullptr;
       }
 
       Value *Offset = GEP->getOperand(2);
-      unsigned BitWidth = Offset->getType()->getIntegerBitWidth();
-      KnownBits Known(BitWidth);
-      computeKnownBits(Offset, Known, DL, 0, nullptr, CI, nullptr);
+      KnownBits Known = computeKnownBits(Offset, DL, 0, nullptr, CI, nullptr);
       Known.Zero.flipAllBits();
       uint64_t ArrSize =
              cast<ArrayType>(GEP->getSourceElementType())->getNumElements();
 
       // KnownZero's bits are flipped, so zeros in KnownZero now represent
       // bits known to be zeros in Offset, and ones in KnowZero represent
       // bits unknown in Offset. Therefore, Offset is known to be in range
       // [0, NullTermIdx] when the flipped KnownZero is non-negative and