diff --git a/include/llvm/IR/PatternMatch.h b/include/llvm/IR/PatternMatch.h
index 072c6c5ece8..542570aaaa2 100644
--- a/include/llvm/IR/PatternMatch.h
+++ b/include/llvm/IR/PatternMatch.h
@@ -262,7 +262,7 @@ template <typename Predicate> struct api_pred_ty : public Predicate {
 };
 
 struct is_one {
-  bool isValue(const APInt &C) { return C == 1; }
+  bool isValue(const APInt &C) { return C.isOneValue(); }
 };
 
 /// \brief Match an integer 1 or a vector with all elements equal to 1.
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index aa7993b875c..e7b626fa688 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -2391,7 +2391,7 @@ static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
   const APInt *C;
   switch (BO.getOpcode()) {
   case Instruction::Add:
-    if (match(BO.getOperand(1), m_APInt(C)) && *C != 0) {
+    if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
       // FIXME: If we have both nuw and nsw, we should reduce the range further.
       if (BO.hasNoUnsignedWrap()) {
         // 'add nuw x, C' produces [C, UINT_MAX].
@@ -2429,7 +2429,7 @@ static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
       Upper = APInt::getSignedMaxValue(Width).ashr(*C) + 1;
     } else if (match(BO.getOperand(0), m_APInt(C))) {
       unsigned ShiftAmount = Width - 1;
-      if (*C != 0 && BO.isExact())
+      if (!C->isNullValue() && BO.isExact())
         ShiftAmount = C->countTrailingZeros();
       if (C->isNegative()) {
         // 'ashr C, x' produces [C, C >> (Width-1)]
@@ -2450,7 +2450,7 @@ static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
     } else if (match(BO.getOperand(0), m_APInt(C))) {
       // 'lshr C, x' produces [C >> (Width-1), C].
       unsigned ShiftAmount = Width - 1;
-      if (*C != 0 && BO.isExact())
+      if (!C->isNullValue() && BO.isExact())
         ShiftAmount = C->countTrailingZeros();
       Lower = C->lshr(ShiftAmount);
       Upper = *C + 1;
@@ -2512,7 +2512,7 @@ static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
     break;
 
   case Instruction::UDiv:
-    if (match(BO.getOperand(1), m_APInt(C)) && *C != 0) {
+    if (match(BO.getOperand(1), m_APInt(C)) && !C->isNullValue()) {
       // 'udiv x, C' produces [0, UINT_MAX / C].
       Upper = APInt::getMaxValue(Width).udiv(*C) + 1;
     } else if (match(BO.getOperand(0), m_APInt(C))) {
@@ -2827,14 +2827,14 @@ static Value *simplifyICmpWithBinOp(CmpInst::Predicate Pred, Value *LHS,
         // - CI2 is one
         // - CI isn't zero
         if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
-            *CI2Val == 1 || !CI->isZero()) {
+            CI2Val->isOneValue() || !CI->isZero()) {
           if (Pred == ICmpInst::ICMP_EQ)
             return ConstantInt::getFalse(RHS->getContext());
           if (Pred == ICmpInst::ICMP_NE)
             return ConstantInt::getTrue(RHS->getContext());
         }
       }
-      if (CIVal->isSignMask() && *CI2Val == 1) {
+      if (CIVal->isSignMask() && CI2Val->isOneValue()) {
         if (Pred == ICmpInst::ICMP_UGT)
           return ConstantInt::getFalse(RHS->getContext());
         if (Pred == ICmpInst::ICMP_ULE)
diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 7204bf51768..ed6386cd689 100644
--- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -991,8 +991,9 @@ static Instruction *foldAddWithConstant(BinaryOperator &Add,
   // Shifts and add used to flip and mask off the low bit:
   // add (ashr (shl i32 X, 31), 31), 1 --> and (not X), 1
   const APInt *C3;
-  if (*C == 1 && match(Op0, m_OneUse(m_AShr(m_Shl(m_Value(X), m_APInt(C2)),
-                                            m_APInt(C3)))) &&
+  if (C->isOneValue() &&
+      match(Op0,
+            m_OneUse(m_AShr(m_Shl(m_Value(X), m_APInt(C2)), m_APInt(C3)))) &&
       C2 == C3 && *C2 == Ty->getScalarSizeInBits() - 1) {
     Value *NotX = Builder.CreateNot(X);
     return BinaryOperator::CreateAnd(NotX, ConstantInt::get(Ty, 1));
@@ -1554,7 +1555,7 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) {
 
     // -(X >>u 31) -> (X >>s 31)
     // -(X >>s 31) -> (X >>u 31)
-    if (*Op0C == 0) {
+    if (Op0C->isNullValue()) {
       Value *X;
       const APInt *ShAmt;
       if (match(Op1, m_LShr(m_Value(X), m_APInt(ShAmt))) &&
diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 1f8319efb3b..bab28c4405f 100644
--- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -172,12 +172,12 @@ Instruction *InstCombiner::OptAndOp(BinaryOperator *Op,
         const APInt& AddRHS = OpRHS->getValue();
 
         // Check to see if any bits below the one bit set in AndRHSV are set.
-        if ((AddRHS & (AndRHSV-1)) == 0) {
+        if ((AddRHS & (AndRHSV - 1)).isNullValue()) {
           // If not, the only thing that can effect the output of the AND is
           // the bit specified by AndRHSV.  If that bit is set, the effect of
           // the XOR is to toggle the bit.  If it is clear, then the ADD has
           // no effect.
-          if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop
+          if ((AddRHS & AndRHSV).isNullValue()) { // Bit is not set, noop
             TheAnd.setOperand(0, X);
             return &TheAnd;
           } else {
@@ -641,7 +641,7 @@ static Value *foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
     // If there is a conflict, we should actually return a false for the
     // whole construct.
     if (((BCst->getValue() & DCst->getValue()) &
-         (CCst->getValue() ^ ECst->getValue())) != 0)
+         (CCst->getValue() ^ ECst->getValue())).getBoolValue())
       return ConstantInt::get(LHS->getType(), !IsAnd);
 
     Value *NewOr1 = Builder->CreateOr(B, D);
@@ -748,7 +748,7 @@ foldAndOrOfEqualityCmpsWithConstants(ICmpInst *LHS, ICmpInst *RHS,
 
   // Special case: get the ordering right when the values wrap around zero.
   // Ie, we assumed the constants were unsigned when swapping earlier.
-  if (*C1 == 0 && C2->isAllOnesValue())
+  if (C1->isNullValue() && C2->isAllOnesValue())
     std::swap(C1, C2);
 
   if (*C1 == *C2 - 1) {
@@ -840,7 +840,8 @@ Value *InstCombiner::foldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
 
       // Check that the low bits are zero.
       APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize);
-      if ((Low & AndC->getValue()) == 0 && (Low & BigC->getValue()) == 0) {
+      if ((Low & AndC->getValue()).isNullValue() &&
+          (Low & BigC->getValue()).isNullValue()) {
         Value *NewAnd = Builder->CreateAnd(V, Low | AndC->getValue());
         APInt N = SmallC->getValue().zext(BigBitSize) | BigC->getValue();
         Value *NewVal = ConstantInt::get(AndC->getType()->getContext(), N);
@@ -1286,7 +1287,7 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
       }
       case Instruction::Sub:
         // -x & 1 -> x & 1
-        if (AndRHSMask == 1 && match(Op0LHS, m_Zero()))
+        if (AndRHSMask.isOneValue() && match(Op0LHS, m_Zero()))
           return BinaryOperator::CreateAnd(Op0RHS, AndRHS);
 
         break;
@@ -1295,7 +1296,7 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
       case Instruction::LShr:
         // (1 << x) & 1 --> zext(x == 0)
         // (1 >> x) & 1 --> zext(x == 0)
-        if (AndRHSMask == 1 && Op0LHS == AndRHS) {
+        if (AndRHSMask.isOneValue() && Op0LHS == AndRHS) {
           Value *NewICmp =
             Builder->CreateICmpEQ(Op0RHS, Constant::getNullValue(I.getType()));
           return new ZExtInst(NewICmp, I.getType());
@@ -2033,7 +2034,7 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
     ConstantInt *C1 = dyn_cast<ConstantInt>(C);
     ConstantInt *C2 = dyn_cast<ConstantInt>(D);
     if (C1 && C2) {  // (A & C1)|(B & C2)
-      if ((C1->getValue() & C2->getValue()) == 0) {
+      if ((C1->getValue() & C2->getValue()).isNullValue()) {
         // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2)
         // iff (C1&C2) == 0 and (N&~C1) == 0
         if (match(A, m_Or(m_Value(V1), m_Value(V2))) &&
@@ -2056,9 +2057,9 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
         // iff (C1&C2) == 0 and (C3&~C1) == 0 and (C4&~C2) == 0.
         ConstantInt *C3 = nullptr, *C4 = nullptr;
         if (match(A, m_Or(m_Value(V1), m_ConstantInt(C3))) &&
-            (C3->getValue() & ~C1->getValue()) == 0 &&
+            (C3->getValue() & ~C1->getValue()).isNullValue() &&
             match(B, m_Or(m_Specific(V1), m_ConstantInt(C4))) &&
-            (C4->getValue() & ~C2->getValue()) == 0) {
+            (C4->getValue() & ~C2->getValue()).isNullValue()) {
           V2 = Builder->CreateOr(V1, ConstantExpr::getOr(C3, C4), "bitfield");
           return BinaryOperator::CreateAnd(V2,
                                 Builder->getInt(C1->getValue()|C2->getValue()));
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 7d545e39662..79f4a473ff4 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -393,7 +393,7 @@ static Value *simplifyX86immShift(const IntrinsicInst &II,
   unsigned BitWidth = SVT->getPrimitiveSizeInBits();
 
   // If shift-by-zero then just return the original value.
-  if (Count == 0)
+  if (Count.isNullValue())
     return Vec;
 
   // Handle cases when Shift >= BitWidth.
@@ -1395,7 +1395,7 @@ static Instruction *foldCttzCtlz(IntrinsicInst &II, InstCombiner &IC) {
   // If the input to cttz/ctlz is known to be non-zero,
   // then change the 'ZeroIsUndef' parameter to 'true'
   // because we know the zero behavior can't affect the result.
-  if (Known.One != 0 ||
+  if (!Known.One.isNullValue() ||
       isKnownNonZero(Op0, IC.getDataLayout(), 0, &IC.getAssumptionCache(), &II,
                      &IC.getDominatorTree())) {
     if (!match(II.getArgOperand(1), m_One())) {
diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 766939c56df..38e95fb1163 100644
--- a/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -661,7 +661,7 @@ Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, ZExtInst &CI,
 
     // zext (x <s  0) to i32 --> x>>u31      true if signbit set.
     // zext (x >s -1) to i32 --> (x>>u31)^1  true if signbit clear.
-    if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV == 0) ||
+    if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV.isNullValue()) ||
         (ICI->getPredicate() == ICmpInst::ICMP_SGT && Op1CV.isAllOnesValue())) {
       if (!DoTransform) return ICI;
 
@@ -688,7 +688,7 @@ Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, ZExtInst &CI,
     // 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()) &&
+    if ((Op1CV.isNullValue() || Op1CV.isPowerOf2()) &&
         // This only works for EQ and NE
         ICI->isEquality()) {
       // If Op1C some other power of two, convert:
@@ -699,7 +699,7 @@ Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, ZExtInst &CI,
         if (!DoTransform) return ICI;
 
         bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
-        if (Op1CV != 0 && (Op1CV != KnownZeroMask)) {
+        if (!Op1CV.isNullValue() && (Op1CV != KnownZeroMask)) {
           // (X&4) == 2 --> false
           // (X&4) != 2 --> true
           Constant *Res = ConstantInt::get(Type::getInt1Ty(CI.getContext()),
@@ -717,7 +717,7 @@ Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, ZExtInst &CI,
                                    In->getName() + ".lobit");
         }
 
-        if ((Op1CV != 0) == isNE) { // Toggle the low bit.
+        if (!Op1CV.isNullValue() == isNE) { // Toggle the low bit.
           Constant *One = ConstantInt::get(In->getType(), 1);
           In = Builder->CreateXor(In, One);
         }
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 91dc4ff1a65..1ef4acfb058 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -127,7 +127,7 @@ static bool isSignBitCheck(ICmpInst::Predicate Pred, const APInt &RHS,
   switch (Pred) {
   case ICmpInst::ICMP_SLT:   // True if LHS s< 0
     TrueIfSigned = true;
-    return RHS == 0;
+    return RHS.isNullValue();
   case ICmpInst::ICMP_SLE:   // True if LHS s<= RHS and RHS == -1
     TrueIfSigned = true;
     return RHS.isAllOnesValue();
@@ -155,10 +155,10 @@ static bool isSignTest(ICmpInst::Predicate &Pred, const APInt &C) {
   if (!ICmpInst::isSigned(Pred))
     return false;
 
-  if (C == 0)
+  if (C.isNullValue())
     return ICmpInst::isRelational(Pred);
 
-  if (C == 1) {
+  if (C.isOneValue()) {
     if (Pred == ICmpInst::ICMP_SLT) {
       Pred = ICmpInst::ICMP_SLE;
       return true;
@@ -1193,7 +1193,7 @@ Instruction *InstCombiner::foldICmpShrConstConst(ICmpInst &I, Value *A,
   };
 
   // Don't bother doing any work for cases which InstSimplify handles.
-  if (AP2 == 0)
+  if (AP2.isNullValue())
     return nullptr;
 
   bool IsAShr = isa<AShrOperator>(I.getOperand(0));
@@ -1252,7 +1252,7 @@ Instruction *InstCombiner::foldICmpShlConstConst(ICmpInst &I, Value *A,
   };
 
   // Don't bother doing any work for cases which InstSimplify handles.
-  if (AP2 == 0)
+  if (AP2.isNullValue())
     return nullptr;
 
   unsigned AP2TrailingZeros = AP2.countTrailingZeros();
@@ -1399,7 +1399,7 @@ Instruction *InstCombiner::foldICmpWithConstant(ICmpInst &Cmp) {
   }
 
   // (icmp sgt smin(PosA, B) 0) -> (icmp sgt B 0)
-  if (*C == 0 && Pred == ICmpInst::ICMP_SGT) {
+  if (C->isNullValue() && Pred == ICmpInst::ICMP_SGT) {
     SelectPatternResult SPR = matchSelectPattern(X, A, B);
     if (SPR.Flavor == SPF_SMIN) {
       if (isKnownPositive(A, DL, 0, &AC, &Cmp, &DT))
@@ -1465,7 +1465,7 @@ Instruction *InstCombiner::foldICmpTruncConstant(ICmpInst &Cmp,
                                                  const APInt *C) {
   ICmpInst::Predicate Pred = Cmp.getPredicate();
   Value *X = Trunc->getOperand(0);
-  if (*C == 1 && C->getBitWidth() > 1) {
+  if (C->isOneValue() && C->getBitWidth() > 1) {
     // icmp slt trunc(signum(V)) 1 --> icmp slt V, 1
     Value *V = nullptr;
     if (Pred == ICmpInst::ICMP_SLT && match(X, m_Signum(m_Value(V))))
@@ -1505,7 +1505,7 @@ Instruction *InstCombiner::foldICmpXorConstant(ICmpInst &Cmp,
   // If this is a comparison that tests the signbit (X < 0) or (x > -1),
   // fold the xor.
   ICmpInst::Predicate Pred = Cmp.getPredicate();
-  if ((Pred == ICmpInst::ICMP_SLT && *C == 0) ||
+  if ((Pred == ICmpInst::ICMP_SLT && C->isNullValue()) ||
       (Pred == ICmpInst::ICMP_SGT && C->isAllOnesValue())) {
 
     // If the sign bit of the XorCst is not set, there is no change to
@@ -1623,7 +1623,7 @@ Instruction *InstCombiner::foldICmpAndShift(ICmpInst &Cmp, BinaryOperator *And,
   // Turn ((X >> Y) & C2) == 0  into  (X & (C2 << Y)) == 0.  The latter is
   // preferable because it allows the C2 << Y expression to be hoisted out of a
   // loop if Y is invariant and X is not.
-  if (Shift->hasOneUse() && *C1 == 0 && Cmp.isEquality() &&
+  if (Shift->hasOneUse() && C1->isNullValue() && Cmp.isEquality() &&
       !Shift->isArithmeticShift() && !isa<Constant>(Shift->getOperand(0))) {
     // Compute C2 << Y.
     Value *NewShift =
@@ -1681,7 +1681,8 @@ Instruction *InstCombiner::foldICmpAndConstConst(ICmpInst &Cmp,
   // (icmp pred (and A, (or (shl 1, B), 1), 0))
   //
   // iff pred isn't signed
-  if (!Cmp.isSigned() && *C1 == 0 && match(And->getOperand(1), m_One())) {
+  if (!Cmp.isSigned() && C1->isNullValue() &&
+      match(And->getOperand(1), m_One())) {
     Constant *One = cast<Constant>(And->getOperand(1));
     Value *Or = And->getOperand(0);
     Value *A, *B, *LShr;
@@ -1764,7 +1765,7 @@ Instruction *InstCombiner::foldICmpAndConstant(ICmpInst &Cmp,
   // (X & C2) != 0 -> (trunc X) <  0
   //   iff C2 is a power of 2 and it masks the sign bit of a legal integer type.
   const APInt *C2;
-  if (And->hasOneUse() && *C == 0 && match(Y, m_APInt(C2))) {
+  if (And->hasOneUse() && C->isNullValue() && match(Y, m_APInt(C2))) {
     int32_t ExactLogBase2 = C2->exactLogBase2();
     if (ExactLogBase2 != -1 && DL.isLegalInteger(ExactLogBase2 + 1)) {
       Type *NTy = IntegerType::get(Cmp.getContext(), ExactLogBase2 + 1);
@@ -1784,7 +1785,7 @@ Instruction *InstCombiner::foldICmpAndConstant(ICmpInst &Cmp,
 Instruction *InstCombiner::foldICmpOrConstant(ICmpInst &Cmp, BinaryOperator *Or,
                                               const APInt *C) {
   ICmpInst::Predicate Pred = Cmp.getPredicate();
-  if (*C == 1) {
+  if (C->isOneValue()) {
     // icmp slt signum(V) 1 --> icmp slt V, 1
     Value *V = nullptr;
     if (Pred == ICmpInst::ICMP_SLT && match(Or, m_Signum(m_Value(V))))
@@ -1801,7 +1802,7 @@ Instruction *InstCombiner::foldICmpOrConstant(ICmpInst &Cmp, BinaryOperator *Or,
     return new ICmpInst(Pred, Or->getOperand(0), Or->getOperand(1));
   }
 
-  if (!Cmp.isEquality() || *C != 0 || !Or->hasOneUse())
+  if (!Cmp.isEquality() || !C->isNullValue() || !Or->hasOneUse())
     return nullptr;
 
   Value *P, *Q;
@@ -2036,7 +2037,8 @@ Instruction *InstCombiner::foldICmpShrConstant(ICmpInst &Cmp,
   // icmp eq/ne (shr X, Y), 0 --> icmp eq/ne X, 0
   Value *X = Shr->getOperand(0);
   CmpInst::Predicate Pred = Cmp.getPredicate();
-  if (Cmp.isEquality() && Shr->isExact() && Shr->hasOneUse() && *C == 0)
+  if (Cmp.isEquality() && Shr->isExact() && Shr->hasOneUse() &&
+      C->isNullValue())
     return new ICmpInst(Pred, X, Cmp.getOperand(1));
 
   const APInt *ShiftVal;
@@ -2178,7 +2180,8 @@ Instruction *InstCombiner::foldICmpDivConstant(ICmpInst &Cmp,
   // INT_MIN will also fail if the divisor is 1. Although folds of all these
   // division-by-constant cases should be present, we can not assert that they
   // have happened before we reach this icmp instruction.
-  if (*C2 == 0 || *C2 == 1 || (DivIsSigned && C2->isAllOnesValue()))
+  if (C2->isNullValue() || C2->isOneValue() ||
+      (DivIsSigned && C2->isAllOnesValue()))
     return nullptr;
 
   // TODO: We could do all of the computations below using APInt.
@@ -2224,7 +2227,7 @@ Instruction *InstCombiner::foldICmpDivConstant(ICmpInst &Cmp,
       HiOverflow = addWithOverflow(HiBound, LoBound, RangeSize, false);
     }
   } else if (C2->isStrictlyPositive()) { // Divisor is > 0.
-    if (*C == 0) {       // (X / pos) op 0
+    if (C->isNullValue()) {       // (X / pos) op 0
       // Can't overflow.  e.g.  X/2 op 0 --> [-1, 2)
       LoBound = ConstantExpr::getNeg(SubOne(RangeSize));
       HiBound = RangeSize;
@@ -2245,7 +2248,7 @@ Instruction *InstCombiner::foldICmpDivConstant(ICmpInst &Cmp,
   } else if (C2->isNegative()) { // Divisor is < 0.
     if (Div->isExact())
       RangeSize = ConstantExpr::getNeg(RangeSize);
-    if (*C == 0) {       // (X / neg) op 0
+    if (C->isNullValue()) { // (X / neg) op 0
       // e.g. X/-5 op 0  --> [-4, 5)
       LoBound = AddOne(RangeSize);
       HiBound = ConstantExpr::getNeg(RangeSize);
@@ -2337,15 +2340,15 @@ Instruction *InstCombiner::foldICmpSubConstant(ICmpInst &Cmp,
       return new ICmpInst(ICmpInst::ICMP_SGE, X, Y);
 
     // (icmp sgt (sub nsw X, Y), 0) -> (icmp sgt X, Y)
-    if (Pred == ICmpInst::ICMP_SGT && *C == 0)
+    if (Pred == ICmpInst::ICMP_SGT && C->isNullValue())
       return new ICmpInst(ICmpInst::ICMP_SGT, X, Y);
 
     // (icmp slt (sub nsw X, Y), 0) -> (icmp slt X, Y)
-    if (Pred == ICmpInst::ICMP_SLT && *C == 0)
+    if (Pred == ICmpInst::ICMP_SLT && C->isNullValue())
       return new ICmpInst(ICmpInst::ICMP_SLT, X, Y);
 
     // (icmp slt (sub nsw X, Y), 1) -> (icmp sle X, Y)
-    if (Pred == ICmpInst::ICMP_SLT && *C == 1)
+    if (Pred == ICmpInst::ICMP_SLT && C->isOneValue())
       return new ICmpInst(ICmpInst::ICMP_SLE, X, Y);
   }
 
@@ -2520,7 +2523,7 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
   switch (BO->getOpcode()) {
   case Instruction::SRem:
     // If we have a signed (X % (2^c)) == 0, turn it into an unsigned one.
-    if (*C == 0 && BO->hasOneUse()) {
+    if (C->isNullValue() && BO->hasOneUse()) {
       const APInt *BOC;
       if (match(BOp1, m_APInt(BOC)) && BOC->sgt(1) && BOC->isPowerOf2()) {
         Value *NewRem = Builder->CreateURem(BOp0, BOp1, BO->getName());
@@ -2537,7 +2540,7 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
         Constant *SubC = ConstantExpr::getSub(RHS, cast<Constant>(BOp1));
         return new ICmpInst(Pred, BOp0, SubC);
       }
-    } else if (*C == 0) {
+    } else if (C->isNullValue()) {
       // Replace ((add A, B) != 0) with (A != -B) if A or B is
       // efficiently invertible, or if the add has just this one use.
       if (Value *NegVal = dyn_castNegVal(BOp1))
@@ -2558,7 +2561,7 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
         // For the xor case, we can xor two constants together, eliminating
         // the explicit xor.
         return new ICmpInst(Pred, BOp0, ConstantExpr::getXor(RHS, BOC));
-      } else if (*C == 0) {
+      } else if (C->isNullValue()) {
         // Replace ((xor A, B) != 0) with (A != B)
         return new ICmpInst(Pred, BOp0, BOp1);
       }
@@ -2571,7 +2574,7 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
         // Replace ((sub BOC, B) != C) with (B != BOC-C).
         Constant *SubC = ConstantExpr::getSub(cast<Constant>(BOp0), RHS);
         return new ICmpInst(Pred, BOp1, SubC);
-      } else if (*C == 0) {
+      } else if (C->isNullValue()) {
         // Replace ((sub A, B) != 0) with (A != B).
         return new ICmpInst(Pred, BOp0, BOp1);
       }
@@ -2609,7 +2612,7 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
       }
 
       // ((X & ~7) == 0) --> X < 8
-      if (*C == 0 && (~(*BOC) + 1).isPowerOf2()) {
+      if (C->isNullValue() && (~(*BOC) + 1).isPowerOf2()) {
         Constant *NegBOC = ConstantExpr::getNeg(cast<Constant>(BOp1));
         auto NewPred = isICMP_NE ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_ULT;
         return new ICmpInst(NewPred, BOp0, NegBOC);
@@ -2618,9 +2621,9 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
     break;
   }
   case Instruction::Mul:
-    if (*C == 0 && BO->hasNoSignedWrap()) {
+    if (C->isNullValue() && BO->hasNoSignedWrap()) {
       const APInt *BOC;
-      if (match(BOp1, m_APInt(BOC)) && *BOC != 0) {
+      if (match(BOp1, m_APInt(BOC)) && !BOC->isNullValue()) {
         // The trivial case (mul X, 0) is handled by InstSimplify.
         // General case : (mul X, C) != 0 iff X != 0
         //                (mul X, C) == 0 iff X == 0
@@ -2629,7 +2632,7 @@ Instruction *InstCombiner::foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
     }
     break;
   case Instruction::UDiv:
-    if (*C == 0) {
+    if (C->isNullValue()) {
       // (icmp eq/ne (udiv A, B), 0) -> (icmp ugt/ule i32 B, A)
       auto NewPred = isICMP_NE ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_UGT;
       return new ICmpInst(NewPred, BOp1, BOp0);
@@ -2668,7 +2671,7 @@ Instruction *InstCombiner::foldICmpIntrinsicWithConstant(ICmpInst &Cmp,
   case Intrinsic::ctpop: {
     // popcount(A) == 0  ->  A == 0 and likewise for !=
     // popcount(A) == bitwidth(A)  ->  A == -1 and likewise for !=
-    bool IsZero = *C == 0;
+    bool IsZero = C->isNullValue();
     if (IsZero || *C == C->getBitWidth()) {
       Worklist.Add(II);
       Cmp.setOperand(0, II->getArgOperand(0));
@@ -3057,7 +3060,8 @@ Instruction *InstCombiner::foldICmpBinOp(ICmpInst &I) {
         break;
 
       const APInt *C;
-      if (match(BO0->getOperand(1), m_APInt(C)) && *C != 0 && *C != 1) {
+      if (match(BO0->getOperand(1), m_APInt(C)) && !C->isNullValue() &&
+          !C->isOneValue()) {
         // icmp eq/ne (X * C), (Y * C) --> icmp (X & Mask), (Y & Mask)
         // Mask = -1 >> count-trailing-zeros(C).
         if (unsigned TZs = C->countTrailingZeros()) {
@@ -4093,7 +4097,7 @@ Instruction *InstCombiner::foldICmpUsingKnownBits(ICmpInst &I) {
 
       // Check if the LHS is 8 >>u x and the result is a power of 2 like 1.
       const APInt *CI;
-      if (Op0KnownZeroInverted == 1 &&
+      if (Op0KnownZeroInverted.isOneValue() &&
           match(LHS, m_LShr(m_Power2(CI), m_Value(X)))) {
         // ((8 >>u X) & 1) == 0 -> X != 3
         // ((8 >>u X) & 1) != 0 -> X == 3
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 4d408359eee..2fcfe464bbd 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -930,7 +930,7 @@ Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) {
         }
       }
 
-      if (*C2 != 0) // avoid X udiv 0
+      if (!C2->isNullValue()) // avoid X udiv 0
         if (Instruction *FoldedDiv = foldOpWithConstantIntoOperand(I))
           return FoldedDiv;
     }
diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 7afb8814fe5..229d59a15c2 100644
--- a/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1478,9 +1478,9 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
   if (!CondVal->getType()->isVectorTy() && !AC.assumptions().empty()) {
     KnownBits Known(1);
     computeKnownBits(CondVal, Known, 0, &SI);
-    if (Known.One == 1)
+    if (Known.One.isOneValue())
       return replaceInstUsesWith(SI, TrueVal);
-    if (Known.Zero == 1)
+    if (Known.Zero.isOneValue())
       return replaceInstUsesWith(SI, FalseVal);
   }
 
diff --git a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 5df55f01b83..03841164b58 100644
--- a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -121,7 +121,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
   }
 
   Known.resetAll();
-  if (DemandedMask == 0)     // Not demanding any bits from V.
+  if (DemandedMask.isNullValue())     // Not demanding any bits from V.
     return UndefValue::get(VTy);
 
   if (Depth == 6)        // Limit search depth.
@@ -488,7 +488,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     // always convert this into a logical shr, even if the shift amount is
     // variable.  The low bit of the shift cannot be an input sign bit unless
     // the shift amount is >= the size of the datatype, which is undefined.
-    if (DemandedMask == 1) {
+    if (DemandedMask.isOneValue()) {
       // Perform the logical shift right.
       Instruction *NewVal = BinaryOperator::CreateLShr(
                         I->getOperand(0), I->getOperand(1), I->getName());
@@ -656,7 +656,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
         // If we don't need any of low bits then return zero,
         // we know that DemandedMask is non-zero already.
         APInt DemandedElts = DemandedMask.zextOrTrunc(ArgWidth);
-        if (DemandedElts == 0)
+        if (DemandedElts.isNullValue())
           return ConstantInt::getNullValue(VTy);
 
         // We know that the upper bits are set to zero.
@@ -908,7 +908,7 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
     return nullptr;
   }
 
-  if (DemandedElts == 0) { // If nothing is demanded, provide undef.
+  if (DemandedElts.isNullValue()) { // If nothing is demanded, provide undef.
     UndefElts = EltMask;
     return UndefValue::get(V->getType());
   }