YQ Connector: support managed ClickHouse

Со стороны dqrun можно обратиться к инстансу коннектора, который работает на streaming стенде, и извлечь данные из облачного CH.

1 files changed, 7535 insertions, 0 deletions

diff --git a/contrib/libs/llvm16/lib/Analysis/ValueTracking.cpp b/contrib/libs/llvm16/lib/Analysis/ValueTracking.cpp
new file mode 100644
index 00000000000..a13bdade320
--- /dev/null
+++ b/contrib/libs/llvm16/lib/Analysis/ValueTracking.cpp
@@ -0,0 +1,7535 @@
+//===- ValueTracking.cpp - Walk computations to compute properties --------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains routines that help analyze properties that chains of
+// computations have.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/APInt.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumeBundleQueries.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/Analysis/EHPersonalities.h"
+#include "llvm/Analysis/GuardUtils.h"
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/Loads.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/OptimizationRemarkEmitter.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/VectorUtils.h"
+#include "llvm/IR/Argument.h"
+#include "llvm/IR/Attributes.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constant.h"
+#include "llvm/IR/ConstantRange.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
+#include "llvm/IR/GlobalAlias.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/InstrTypes.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/IntrinsicsAArch64.h"
+#include "llvm/IR/IntrinsicsRISCV.h"
+#include "llvm/IR/IntrinsicsX86.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Operator.h"
+#include "llvm/IR/PatternMatch.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/User.h"
+#include "llvm/IR/Value.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/KnownBits.h"
+#include "llvm/Support/MathExtras.h"
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <optional>
+#include <utility>
+
+using namespace llvm;
+using namespace llvm::PatternMatch;
+
+// Controls the number of uses of the value searched for possible
+// dominating comparisons.
+static cl::opt<unsigned> DomConditionsMaxUses("dom-conditions-max-uses",
+                                              cl::Hidden, cl::init(20));
+
+
+/// Returns the bitwidth of the given scalar or pointer type. For vector types,
+/// returns the element type's bitwidth.
+static unsigned getBitWidth(Type *Ty, const DataLayout &DL) {
+  if (unsigned BitWidth = Ty->getScalarSizeInBits())
+    return BitWidth;
+
+  return DL.getPointerTypeSizeInBits(Ty);
+}
+
+namespace {
+
+// Simplifying using an assume can only be done in a particular control-flow
+// context (the context instruction provides that context). If an assume and
+// the context instruction are not in the same block then the DT helps in
+// figuring out if we can use it.
+struct Query {
+  const DataLayout &DL;
+  AssumptionCache *AC;
+  const Instruction *CxtI;
+  const DominatorTree *DT;
+
+  // Unlike the other analyses, this may be a nullptr because not all clients
+  // provide it currently.
+  OptimizationRemarkEmitter *ORE;
+
+  /// If true, it is safe to use metadata during simplification.
+  InstrInfoQuery IIQ;
+
+  Query(const DataLayout &DL, AssumptionCache *AC, const Instruction *CxtI,
+        const DominatorTree *DT, bool UseInstrInfo,
+        OptimizationRemarkEmitter *ORE = nullptr)
+      : DL(DL), AC(AC), CxtI(CxtI), DT(DT), ORE(ORE), IIQ(UseInstrInfo) {}
+};
+
+} // end anonymous namespace
+
+// Given the provided Value and, potentially, a context instruction, return
+// the preferred context instruction (if any).
+static const Instruction *safeCxtI(const Value *V, const Instruction *CxtI) {
+  // If we've been provided with a context instruction, then use that (provided
+  // it has been inserted).
+  if (CxtI && CxtI->getParent())
+    return CxtI;
+
+  // If the value is really an already-inserted instruction, then use that.
+  CxtI = dyn_cast<Instruction>(V);
+  if (CxtI && CxtI->getParent())
+    return CxtI;
+
+  return nullptr;
+}
+
+static const Instruction *safeCxtI(const Value *V1, const Value *V2, const Instruction *CxtI) {
+  // If we've been provided with a context instruction, then use that (provided
+  // it has been inserted).
+  if (CxtI && CxtI->getParent())
+    return CxtI;
+
+  // If the value is really an already-inserted instruction, then use that.
+  CxtI = dyn_cast<Instruction>(V1);
+  if (CxtI && CxtI->getParent())
+    return CxtI;
+
+  CxtI = dyn_cast<Instruction>(V2);
+  if (CxtI && CxtI->getParent())
+    return CxtI;
+
+  return nullptr;
+}
+
+static bool getShuffleDemandedElts(const ShuffleVectorInst *Shuf,
+                                   const APInt &DemandedElts,
+                                   APInt &DemandedLHS, APInt &DemandedRHS) {
+  if (isa<ScalableVectorType>(Shuf->getType())) {
+    assert(DemandedElts == APInt(1,1));
+    DemandedLHS = DemandedRHS = DemandedElts;
+    return true;
+  }
+
+  int NumElts =
+      cast<FixedVectorType>(Shuf->getOperand(0)->getType())->getNumElements();
+  return llvm::getShuffleDemandedElts(NumElts, Shuf->getShuffleMask(),
+                                      DemandedElts, DemandedLHS, DemandedRHS);
+}
+
+static void computeKnownBits(const Value *V, const APInt &DemandedElts,
+                             KnownBits &Known, unsigned Depth, const Query &Q);
+
+static void computeKnownBits(const Value *V, KnownBits &Known, unsigned Depth,
+                             const Query &Q) {
+  // Since the number of lanes in a scalable vector is unknown at compile time,
+  // we track one bit which is implicitly broadcast to all lanes.  This means
+  // that all lanes in a scalable vector are considered demanded.
+  auto *FVTy = dyn_cast<FixedVectorType>(V->getType());
+  APInt DemandedElts =
+      FVTy ? APInt::getAllOnes(FVTy->getNumElements()) : APInt(1, 1);
+  computeKnownBits(V, DemandedElts, Known, Depth, Q);
+}
+
+void llvm::computeKnownBits(const Value *V, KnownBits &Known,
+                            const DataLayout &DL, unsigned Depth,
+                            AssumptionCache *AC, const Instruction *CxtI,
+                            const DominatorTree *DT,
+                            OptimizationRemarkEmitter *ORE, bool UseInstrInfo) {
+  ::computeKnownBits(V, Known, Depth,
+                     Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo, ORE));
+}
+
+void llvm::computeKnownBits(const Value *V, const APInt &DemandedElts,
+                            KnownBits &Known, const DataLayout &DL,
+                            unsigned Depth, AssumptionCache *AC,
+                            const Instruction *CxtI, const DominatorTree *DT,
+                            OptimizationRemarkEmitter *ORE, bool UseInstrInfo) {
+  ::computeKnownBits(V, DemandedElts, Known, Depth,
+                     Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo, ORE));
+}
+
+static KnownBits computeKnownBits(const Value *V, const APInt &DemandedElts,
+                                  unsigned Depth, const Query &Q);
+
+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,
+                                 OptimizationRemarkEmitter *ORE,
+                                 bool UseInstrInfo) {
+  return ::computeKnownBits(
+      V, Depth, Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo, ORE));
+}
+
+KnownBits llvm::computeKnownBits(const Value *V, const APInt &DemandedElts,
+                                 const DataLayout &DL, unsigned Depth,
+                                 AssumptionCache *AC, const Instruction *CxtI,
+                                 const DominatorTree *DT,
+                                 OptimizationRemarkEmitter *ORE,
+                                 bool UseInstrInfo) {
+  return ::computeKnownBits(
+      V, DemandedElts, Depth,
+      Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo, ORE));
+}
+
+bool llvm::haveNoCommonBitsSet(const Value *LHS, const Value *RHS,
+                               const DataLayout &DL, AssumptionCache *AC,
+                               const Instruction *CxtI, const DominatorTree *DT,
+                               bool UseInstrInfo) {
+  assert(LHS->getType() == RHS->getType() &&
+         "LHS and RHS should have the same type");
+  assert(LHS->getType()->isIntOrIntVectorTy() &&
+         "LHS and RHS should be integers");
+  // Look for an inverted mask: (X & ~M) op (Y & M).
+  {
+    Value *M;
+    if (match(LHS, m_c_And(m_Not(m_Value(M)), m_Value())) &&
+        match(RHS, m_c_And(m_Specific(M), m_Value())))
+      return true;
+    if (match(RHS, m_c_And(m_Not(m_Value(M)), m_Value())) &&
+        match(LHS, m_c_And(m_Specific(M), m_Value())))
+      return true;
+  }
+
+  // X op (Y & ~X)
+  if (match(RHS, m_c_And(m_Not(m_Specific(LHS)), m_Value())) ||
+      match(LHS, m_c_And(m_Not(m_Specific(RHS)), m_Value())))
+    return true;
+
+  // X op ((X & Y) ^ Y) -- this is the canonical form of the previous pattern
+  // for constant Y.
+  Value *Y;
+  if (match(RHS,
+            m_c_Xor(m_c_And(m_Specific(LHS), m_Value(Y)), m_Deferred(Y))) ||
+      match(LHS, m_c_Xor(m_c_And(m_Specific(RHS), m_Value(Y)), m_Deferred(Y))))
+    return true;
+
+  // Peek through extends to find a 'not' of the other side:
+  // (ext Y) op ext(~Y)
+  // (ext ~Y) op ext(Y)
+  if ((match(LHS, m_ZExtOrSExt(m_Value(Y))) &&
+       match(RHS, m_ZExtOrSExt(m_Not(m_Specific(Y))))) ||
+      (match(RHS, m_ZExtOrSExt(m_Value(Y))) &&
+       match(LHS, m_ZExtOrSExt(m_Not(m_Specific(Y))))))
+    return true;
+
+  // Look for: (A & B) op ~(A | B)
+  {
+    Value *A, *B;
+    if (match(LHS, m_And(m_Value(A), m_Value(B))) &&
+        match(RHS, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
+      return true;
+    if (match(RHS, m_And(m_Value(A), m_Value(B))) &&
+        match(LHS, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
+      return true;
+  }
+  IntegerType *IT = cast<IntegerType>(LHS->getType()->getScalarType());
+  KnownBits LHSKnown(IT->getBitWidth());
+  KnownBits RHSKnown(IT->getBitWidth());
+  computeKnownBits(LHS, LHSKnown, DL, 0, AC, CxtI, DT, nullptr, UseInstrInfo);
+  computeKnownBits(RHS, RHSKnown, DL, 0, AC, CxtI, DT, nullptr, UseInstrInfo);
+  return KnownBits::haveNoCommonBitsSet(LHSKnown, RHSKnown);
+}
+
+bool llvm::isOnlyUsedInZeroEqualityComparison(const Instruction *I) {
+  return !I->user_empty() && all_of(I->users(), [](const User *U) {
+    ICmpInst::Predicate P;
+    return match(U, m_ICmp(P, m_Value(), m_Zero())) && ICmpInst::isEquality(P);
+  });
+}
+
+static bool isKnownToBeAPowerOfTwo(const Value *V, bool OrZero, unsigned Depth,
+                                   const Query &Q);
+
+bool llvm::isKnownToBeAPowerOfTwo(const Value *V, const DataLayout &DL,
+                                  bool OrZero, unsigned Depth,
+                                  AssumptionCache *AC, const Instruction *CxtI,
+                                  const DominatorTree *DT, bool UseInstrInfo) {
+  return ::isKnownToBeAPowerOfTwo(
+      V, OrZero, Depth, Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo));
+}
+
+static bool isKnownNonZero(const Value *V, const APInt &DemandedElts,
+                           unsigned Depth, const Query &Q);
+
+static bool isKnownNonZero(const Value *V, unsigned Depth, const Query &Q);
+
+bool llvm::isKnownNonZero(const Value *V, const DataLayout &DL, unsigned Depth,
+                          AssumptionCache *AC, const Instruction *CxtI,
+                          const DominatorTree *DT, bool UseInstrInfo) {
+  return ::isKnownNonZero(V, Depth,
+                          Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo));
+}
+
+bool llvm::isKnownNonNegative(const Value *V, const DataLayout &DL,
+                              unsigned Depth, AssumptionCache *AC,
+                              const Instruction *CxtI, const DominatorTree *DT,
+                              bool UseInstrInfo) {
+  KnownBits Known =
+      computeKnownBits(V, DL, Depth, AC, CxtI, DT, nullptr, UseInstrInfo);
+  return Known.isNonNegative();
+}
+
+bool llvm::isKnownPositive(const Value *V, const DataLayout &DL, unsigned Depth,
+                           AssumptionCache *AC, const Instruction *CxtI,
+                           const DominatorTree *DT, bool UseInstrInfo) {
+  if (auto *CI = dyn_cast<ConstantInt>(V))
+    return CI->getValue().isStrictlyPositive();
+
+  // TODO: We'd doing two recursive queries here.  We should factor this such
+  // that only a single query is needed.
+  return isKnownNonNegative(V, DL, Depth, AC, CxtI, DT, UseInstrInfo) &&
+         isKnownNonZero(V, DL, Depth, AC, CxtI, DT, UseInstrInfo);
+}
+
+bool llvm::isKnownNegative(const Value *V, const DataLayout &DL, unsigned Depth,
+                           AssumptionCache *AC, const Instruction *CxtI,
+                           const DominatorTree *DT, bool UseInstrInfo) {
+  KnownBits Known =
+      computeKnownBits(V, DL, Depth, AC, CxtI, DT, nullptr, UseInstrInfo);
+  return Known.isNegative();
+}
+
+static bool isKnownNonEqual(const Value *V1, const Value *V2, unsigned Depth,
+                            const Query &Q);
+
+bool llvm::isKnownNonEqual(const Value *V1, const Value *V2,
+                           const DataLayout &DL, AssumptionCache *AC,
+                           const Instruction *CxtI, const DominatorTree *DT,
+                           bool UseInstrInfo) {
+  return ::isKnownNonEqual(V1, V2, 0,
+                           Query(DL, AC, safeCxtI(V2, V1, CxtI), DT,
+                                 UseInstrInfo, /*ORE=*/nullptr));
+}
+
+static bool MaskedValueIsZero(const Value *V, const APInt &Mask, unsigned Depth,
+                              const Query &Q);
+
+bool llvm::MaskedValueIsZero(const Value *V, const APInt &Mask,
+                             const DataLayout &DL, unsigned Depth,
+                             AssumptionCache *AC, const Instruction *CxtI,
+                             const DominatorTree *DT, bool UseInstrInfo) {
+  return ::MaskedValueIsZero(
+      V, Mask, Depth, Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo));
+}
+
+static unsigned ComputeNumSignBits(const Value *V, const APInt &DemandedElts,
+                                   unsigned Depth, const Query &Q);
+
+static unsigned ComputeNumSignBits(const Value *V, unsigned Depth,
+                                   const Query &Q) {
+  auto *FVTy = dyn_cast<FixedVectorType>(V->getType());
+  APInt DemandedElts =
+      FVTy ? APInt::getAllOnes(FVTy->getNumElements()) : APInt(1, 1);
+  return ComputeNumSignBits(V, DemandedElts, Depth, Q);
+}
+
+unsigned llvm::ComputeNumSignBits(const Value *V, const DataLayout &DL,
+                                  unsigned Depth, AssumptionCache *AC,
+                                  const Instruction *CxtI,
+                                  const DominatorTree *DT, bool UseInstrInfo) {
+  return ::ComputeNumSignBits(
+      V, Depth, Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo));
+}
+
+unsigned llvm::ComputeMaxSignificantBits(const Value *V, const DataLayout &DL,
+                                         unsigned Depth, AssumptionCache *AC,
+                                         const Instruction *CxtI,
+                                         const DominatorTree *DT) {
+  unsigned SignBits = ComputeNumSignBits(V, DL, Depth, AC, CxtI, DT);
+  return V->getType()->getScalarSizeInBits() - SignBits + 1;
+}
+
+static void computeKnownBitsAddSub(bool Add, const Value *Op0, const Value *Op1,
+                                   bool NSW, const APInt &DemandedElts,
+                                   KnownBits &KnownOut, KnownBits &Known2,
+                                   unsigned Depth, const Query &Q) {
+  computeKnownBits(Op1, DemandedElts, KnownOut, Depth + 1, Q);
+
+  // If one operand is unknown and we have no nowrap information,
+  // the result will be unknown independently of the second operand.
+  if (KnownOut.isUnknown() && !NSW)
+    return;
+
+  computeKnownBits(Op0, DemandedElts, Known2, Depth + 1, Q);
+  KnownOut = KnownBits::computeForAddSub(Add, NSW, Known2, KnownOut);
+}
+
+static void computeKnownBitsMul(const Value *Op0, const Value *Op1, bool NSW,
+                                const APInt &DemandedElts, KnownBits &Known,
+                                KnownBits &Known2, unsigned Depth,
+                                const Query &Q) {
+  computeKnownBits(Op1, DemandedElts, Known, Depth + 1, Q);
+  computeKnownBits(Op0, DemandedElts, Known2, Depth + 1, Q);
+
+  bool isKnownNegative = false;
+  bool isKnownNonNegative = false;
+  // If the multiplication is known not to overflow, compute the sign bit.
+  if (NSW) {
+    if (Op0 == Op1) {
+      // The product of a number with itself is non-negative.
+      isKnownNonNegative = true;
+    } else {
+      bool isKnownNonNegativeOp1 = Known.isNonNegative();
+      bool isKnownNonNegativeOp0 = Known2.isNonNegative();
+      bool isKnownNegativeOp1 = Known.isNegative();
+      bool isKnownNegativeOp0 = Known2.isNegative();
+      // The product of two numbers with the same sign is non-negative.
+      isKnownNonNegative = (isKnownNegativeOp1 && isKnownNegativeOp0) ||
+                           (isKnownNonNegativeOp1 && isKnownNonNegativeOp0);
+      // The product of a negative number and a non-negative number is either
+      // negative or zero.
+      if (!isKnownNonNegative)
+        isKnownNegative =
+            (isKnownNegativeOp1 && isKnownNonNegativeOp0 &&
+             Known2.isNonZero()) ||
+            (isKnownNegativeOp0 && isKnownNonNegativeOp1 && Known.isNonZero());
+    }
+  }
+
+  bool SelfMultiply = Op0 == Op1;
+  // TODO: SelfMultiply can be poison, but not undef.
+  if (SelfMultiply)
+    SelfMultiply &=
+        isGuaranteedNotToBeUndefOrPoison(Op0, Q.AC, Q.CxtI, Q.DT, Depth + 1);
+  Known = KnownBits::mul(Known, Known2, SelfMultiply);
+
+  // Only make use of no-wrap flags if we failed to compute the sign bit
+  // directly.  This matters if the multiplication always overflows, in
+  // which case we prefer to follow the result of the direct computation,
+  // though as the program is invoking undefined behaviour we can choose
+  // whatever we like here.
+  if (isKnownNonNegative && !Known.isNegative())
+    Known.makeNonNegative();
+  else if (isKnownNegative && !Known.isNonNegative())
+    Known.makeNegative();
+}
+
+void llvm::computeKnownBitsFromRangeMetadata(const MDNode &Ranges,
+                                             KnownBits &Known) {
+  unsigned BitWidth = Known.getBitWidth();
+  unsigned NumRanges = Ranges.getNumOperands() / 2;
+  assert(NumRanges >= 1);
+
+  Known.Zero.setAllBits();
+  Known.One.setAllBits();
+
+  for (unsigned i = 0; i < NumRanges; ++i) {
+    ConstantInt *Lower =
+        mdconst::extract<ConstantInt>(Ranges.getOperand(2 * i + 0));
+    ConstantInt *Upper =
+        mdconst::extract<ConstantInt>(Ranges.getOperand(2 * i + 1));
+    ConstantRange Range(Lower->getValue(), Upper->getValue());
+
+    // The first CommonPrefixBits of all values in Range are equal.
+    unsigned CommonPrefixBits =
+        (Range.getUnsignedMax() ^ Range.getUnsignedMin()).countLeadingZeros();
+    APInt Mask = APInt::getHighBitsSet(BitWidth, CommonPrefixBits);
+    APInt UnsignedMax = Range.getUnsignedMax().zextOrTrunc(BitWidth);
+    Known.One &= UnsignedMax & Mask;
+    Known.Zero &= ~UnsignedMax & Mask;
+  }
+}
+
+static bool isEphemeralValueOf(const Instruction *I, const Value *E) {
+  SmallVector<const Value *, 16> WorkSet(1, I);
+  SmallPtrSet<const Value *, 32> Visited;
+  SmallPtrSet<const Value *, 16> EphValues;
+
+  // The instruction defining an assumption's condition itself is always
+  // considered ephemeral to that assumption (even if it has other
+  // non-ephemeral users). See r246696's test case for an example.
+  if (is_contained(I->operands(), E))
+    return true;
+
+  while (!WorkSet.empty()) {
+    const Value *V = WorkSet.pop_back_val();
+    if (!Visited.insert(V).second)
+      continue;
+
+    // If all uses of this value are ephemeral, then so is this value.
+    if (llvm::all_of(V->users(), [&](const User *U) {
+                                   return EphValues.count(U);
+                                 })) {
+      if (V == E)
+        return true;
+
+      if (V == I || (isa<Instruction>(V) &&
+                     !cast<Instruction>(V)->mayHaveSideEffects() &&
+                     !cast<Instruction>(V)->isTerminator())) {
+       EphValues.insert(V);
+       if (const User *U = dyn_cast<User>(V))
+         append_range(WorkSet, U->operands());
+      }
+    }
+  }
+
+  return false;
+}
+
+// Is this an intrinsic that cannot be speculated but also cannot trap?
+bool llvm::isAssumeLikeIntrinsic(const Instruction *I) {
+  if (const IntrinsicInst *CI = dyn_cast<IntrinsicInst>(I))
+    return CI->isAssumeLikeIntrinsic();
+
+  return false;
+}
+
+bool llvm::isValidAssumeForContext(const Instruction *Inv,
+                                   const Instruction *CxtI,
+                                   const DominatorTree *DT) {
+  // There are two restrictions on the use of an assume:
+  //  1. The assume must dominate the context (or the control flow must
+  //     reach the assume whenever it reaches the context).
+  //  2. The context must not be in the assume's set of ephemeral values
+  //     (otherwise we will use the assume to prove that the condition
+  //     feeding the assume is trivially true, thus causing the removal of
+  //     the assume).
+
+  if (Inv->getParent() == CxtI->getParent()) {
+    // If Inv and CtxI are in the same block, check if the assume (Inv) is first
+    // in the BB.
+    if (Inv->comesBefore(CxtI))
+      return true;
+
+    // Don't let an assume affect itself - this would cause the problems
+    // `isEphemeralValueOf` is trying to prevent, and it would also make
+    // the loop below go out of bounds.
+    if (Inv == CxtI)
+      return false;
+
+    // The context comes first, but they're both in the same block.
+    // Make sure there is nothing in between that might interrupt
+    // the control flow, not even CxtI itself.
+    // We limit the scan distance between the assume and its context instruction
+    // to avoid a compile-time explosion. This limit is chosen arbitrarily, so
+    // it can be adjusted if needed (could be turned into a cl::opt).
+    auto Range = make_range(CxtI->getIterator(), Inv->getIterator());
+    if (!isGuaranteedToTransferExecutionToSuccessor(Range, 15))
+      return false;
+
+    return !isEphemeralValueOf(Inv, CxtI);
+  }
+
+  // Inv and CxtI are in different blocks.
+  if (DT) {
+    if (DT->dominates(Inv, CxtI))
+      return true;
+  } else if (Inv->getParent() == CxtI->getParent()->getSinglePredecessor()) {
+    // We don't have a DT, but this trivially dominates.
+    return true;
+  }
+
+  return false;
+}
+
+static bool cmpExcludesZero(CmpInst::Predicate Pred, const Value *RHS) {
+  // v u> y implies v != 0.
+  if (Pred == ICmpInst::ICMP_UGT)
+    return true;
+
+  // Special-case v != 0 to also handle v != null.
+  if (Pred == ICmpInst::ICMP_NE)
+    return match(RHS, m_Zero());
+
+  // All other predicates - rely on generic ConstantRange handling.
+  const APInt *C;
+  if (!match(RHS, m_APInt(C)))
+    return false;
+
+  ConstantRange TrueValues = ConstantRange::makeExactICmpRegion(Pred, *C);
+  return !TrueValues.contains(APInt::getZero(C->getBitWidth()));
+}
+
+static bool isKnownNonZeroFromAssume(const Value *V, const Query &Q) {
+  // Use of assumptions is context-sensitive. If we don't have a context, we
+  // cannot use them!
+  if (!Q.AC || !Q.CxtI)
+    return false;
+
+  if (Q.CxtI && V->getType()->isPointerTy()) {
+    SmallVector<Attribute::AttrKind, 2> AttrKinds{Attribute::NonNull};
+    if (!NullPointerIsDefined(Q.CxtI->getFunction(),
+                              V->getType()->getPointerAddressSpace()))
+      AttrKinds.push_back(Attribute::Dereferenceable);
+
+    if (getKnowledgeValidInContext(V, AttrKinds, Q.CxtI, Q.DT, Q.AC))
+      return true;
+  }
+
+  for (auto &AssumeVH : Q.AC->assumptionsFor(V)) {
+    if (!AssumeVH)
+      continue;
+    CondGuardInst *I = cast<CondGuardInst>(AssumeVH);
+    assert(I->getFunction() == Q.CxtI->getFunction() &&
+           "Got assumption for the wrong function!");
+
+    // Warning: This loop can end up being somewhat performance sensitive.
+    // We're running this loop for once for each value queried resulting in a
+    // runtime of ~O(#assumes * #values).
+
+    Value *RHS;
+    CmpInst::Predicate Pred;
+    auto m_V = m_CombineOr(m_Specific(V), m_PtrToInt(m_Specific(V)));
+    if (!match(I->getArgOperand(0), m_c_ICmp(Pred, m_V, m_Value(RHS))))
+      return false;
+
+    if (cmpExcludesZero(Pred, RHS) && isValidAssumeForContext(I, Q.CxtI, Q.DT))
+      return true;
+  }
+
+  return false;
+}
+
+static void computeKnownBitsFromAssume(const Value *V, KnownBits &Known,
+                                       unsigned Depth, const Query &Q) {
+  // Use of assumptions is context-sensitive. If we don't have a context, we
+  // cannot use them!
+  if (!Q.AC || !Q.CxtI)
+    return;
+
+  unsigned BitWidth = Known.getBitWidth();
+
+  // Refine Known set if the pointer alignment is set by assume bundles.
+  if (V->getType()->isPointerTy()) {
+    if (RetainedKnowledge RK = getKnowledgeValidInContext(
+            V, {Attribute::Alignment}, Q.CxtI, Q.DT, Q.AC)) {
+      if (isPowerOf2_64(RK.ArgValue))
+        Known.Zero.setLowBits(Log2_64(RK.ArgValue));
+    }
+  }
+
+  // Note that the patterns below need to be kept in sync with the code
+  // in AssumptionCache::updateAffectedValues.
+
+  for (auto &AssumeVH : Q.AC->assumptionsFor(V)) {
+    if (!AssumeVH)
+      continue;
+    CondGuardInst *I = cast<CondGuardInst>(AssumeVH);
+    assert(I->getParent()->getParent() == Q.CxtI->getParent()->getParent() &&
+           "Got assumption for the wrong function!");
+
+    // Warning: This loop can end up being somewhat performance sensitive.
+    // We're running this loop for once for each value queried resulting in a
+    // runtime of ~O(#assumes * #values).
+
+    Value *Arg = I->getArgOperand(0);
+
+    if (Arg == V && isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+      assert(BitWidth == 1 && "assume operand is not i1?");
+      Known.setAllOnes();
+      return;
+    }
+    if (match(Arg, m_Not(m_Specific(V))) &&
+        isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+      assert(BitWidth == 1 && "assume operand is not i1?");
+      Known.setAllZero();
+      return;
+    }
+
+    // The remaining tests are all recursive, so bail out if we hit the limit.
+    if (Depth == MaxAnalysisRecursionDepth)
+      continue;
+
+    ICmpInst *Cmp = dyn_cast<ICmpInst>(Arg);
+    if (!Cmp)
+      continue;
+
+    // We are attempting to compute known bits for the operands of an assume.
+    // Do not try to use other assumptions for those recursive calls because
+    // that can lead to mutual recursion and a compile-time explosion.
+    // An example of the mutual recursion: computeKnownBits can call
+    // isKnownNonZero which calls computeKnownBitsFromAssume (this function)
+    // and so on.
+    Query QueryNoAC = Q;
+    QueryNoAC.AC = nullptr;
+
+    // Note that ptrtoint may change the bitwidth.
+    Value *A, *B;
+    auto m_V = m_CombineOr(m_Specific(V), m_PtrToInt(m_Specific(V)));
+
+    CmpInst::Predicate Pred;
+    uint64_t C;
+    switch (Cmp->getPredicate()) {
+    default:
+      break;
+    case ICmpInst::ICMP_EQ:
+      // assume(v = a)
+      if (match(Cmp, m_c_ICmp(Pred, m_V, m_Value(A))) &&
+          isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        Known.Zero |= RHSKnown.Zero;
+        Known.One  |= RHSKnown.One;
+      // assume(v & b = a)
+      } else if (match(Cmp,
+                       m_c_ICmp(Pred, m_c_And(m_V, m_Value(B)), m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        KnownBits MaskKnown =
+            computeKnownBits(B, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        // For those bits in the mask that are known to be one, we can propagate
+        // known bits from the RHS to V.
+        Known.Zero |= RHSKnown.Zero & MaskKnown.One;
+        Known.One  |= RHSKnown.One  & MaskKnown.One;
+      // assume(~(v & b) = a)
+      } else if (match(Cmp, m_c_ICmp(Pred, m_Not(m_c_And(m_V, m_Value(B))),
+                                     m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        KnownBits MaskKnown =
+            computeKnownBits(B, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        // For those bits in the mask that are known to be one, we can propagate
+        // inverted known bits from the RHS to V.
+        Known.Zero |= RHSKnown.One  & MaskKnown.One;
+        Known.One  |= RHSKnown.Zero & MaskKnown.One;
+      // assume(v | b = a)
+      } else if (match(Cmp,
+                       m_c_ICmp(Pred, m_c_Or(m_V, m_Value(B)), m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        KnownBits BKnown =
+            computeKnownBits(B, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        // For those bits in B that are known to be zero, we can propagate known
+        // bits from the RHS to V.
+        Known.Zero |= RHSKnown.Zero & BKnown.Zero;
+        Known.One  |= RHSKnown.One  & BKnown.Zero;
+      // assume(~(v | b) = a)
+      } else if (match(Cmp, m_c_ICmp(Pred, m_Not(m_c_Or(m_V, m_Value(B))),
+                                     m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        KnownBits BKnown =
+            computeKnownBits(B, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        // For those bits in B that are known to be zero, we can propagate
+        // inverted known bits from the RHS to V.
+        Known.Zero |= RHSKnown.One  & BKnown.Zero;
+        Known.One  |= RHSKnown.Zero & BKnown.Zero;
+      // assume(v ^ b = a)
+      } else if (match(Cmp,
+                       m_c_ICmp(Pred, m_c_Xor(m_V, m_Value(B)), m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        KnownBits BKnown =
+            computeKnownBits(B, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        // For those bits in B that are known to be zero, we can propagate known
+        // bits from the RHS to V. For those bits in B that are known to be one,
+        // we can propagate inverted known bits from the RHS to V.
+        Known.Zero |= RHSKnown.Zero & BKnown.Zero;
+        Known.One  |= RHSKnown.One  & BKnown.Zero;
+        Known.Zero |= RHSKnown.One  & BKnown.One;
+        Known.One  |= RHSKnown.Zero & BKnown.One;
+      // assume(~(v ^ b) = a)
+      } else if (match(Cmp, m_c_ICmp(Pred, m_Not(m_c_Xor(m_V, m_Value(B))),
+                                     m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        KnownBits BKnown =
+            computeKnownBits(B, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        // For those bits in B that are known to be zero, we can propagate
+        // inverted known bits from the RHS to V. For those bits in B that are
+        // known to be one, we can propagate known bits from the RHS to V.
+        Known.Zero |= RHSKnown.One  & BKnown.Zero;
+        Known.One  |= RHSKnown.Zero & BKnown.Zero;
+        Known.Zero |= RHSKnown.Zero & BKnown.One;
+        Known.One  |= RHSKnown.One  & BKnown.One;
+      // assume(v << c = a)
+      } else if (match(Cmp, m_c_ICmp(Pred, m_Shl(m_V, m_ConstantInt(C)),
+                                     m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT) && C < BitWidth) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        // For those bits in RHS that are known, we can propagate them to known
+        // bits in V shifted to the right by C.
+        RHSKnown.Zero.lshrInPlace(C);
+        Known.Zero |= RHSKnown.Zero;
+        RHSKnown.One.lshrInPlace(C);
+        Known.One  |= RHSKnown.One;
+      // assume(~(v << c) = a)
+      } else if (match(Cmp, m_c_ICmp(Pred, m_Not(m_Shl(m_V, m_ConstantInt(C))),
+                                     m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT) && C < BitWidth) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        // For those bits in RHS that are known, we can propagate them inverted
+        // to known bits in V shifted to the right by C.
+        RHSKnown.One.lshrInPlace(C);
+        Known.Zero |= RHSKnown.One;
+        RHSKnown.Zero.lshrInPlace(C);
+        Known.One  |= RHSKnown.Zero;
+      // assume(v >> c = a)
+      } else if (match(Cmp, m_c_ICmp(Pred, m_Shr(m_V, m_ConstantInt(C)),
+                                     m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT) && C < BitWidth) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        // For those bits in RHS that are known, we can propagate them to known
+        // bits in V shifted to the right by C.
+        Known.Zero |= RHSKnown.Zero << C;
+        Known.One  |= RHSKnown.One  << C;
+      // assume(~(v >> c) = a)
+      } else if (match(Cmp, m_c_ICmp(Pred, m_Not(m_Shr(m_V, m_ConstantInt(C))),
+                                     m_Value(A))) &&
+                 isValidAssumeForContext(I, Q.CxtI, Q.DT) && C < BitWidth) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+        // For those bits in RHS that are known, we can propagate them inverted
+        // to known bits in V shifted to the right by C.
+        Known.Zero |= RHSKnown.One  << C;
+        Known.One  |= RHSKnown.Zero << C;
+      }
+      break;
+    case ICmpInst::ICMP_SGE:
+      // assume(v >=_s c) where c is non-negative
+      if (match(Cmp, m_ICmp(Pred, m_V, m_Value(A))) &&
+          isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth + 1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        if (RHSKnown.isNonNegative()) {
+          // We know that the sign bit is zero.
+          Known.makeNonNegative();
+        }
+      }
+      break;
+    case ICmpInst::ICMP_SGT:
+      // assume(v >_s c) where c is at least -1.
+      if (match(Cmp, m_ICmp(Pred, m_V, m_Value(A))) &&
+          isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth + 1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        if (RHSKnown.isAllOnes() || RHSKnown.isNonNegative()) {
+          // We know that the sign bit is zero.
+          Known.makeNonNegative();
+        }
+      }
+      break;
+    case ICmpInst::ICMP_SLE:
+      // assume(v <=_s c) where c is negative
+      if (match(Cmp, m_ICmp(Pred, m_V, m_Value(A))) &&
+          isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth + 1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        if (RHSKnown.isNegative()) {
+          // We know that the sign bit is one.
+          Known.makeNegative();
+        }
+      }
+      break;
+    case ICmpInst::ICMP_SLT:
+      // assume(v <_s c) where c is non-positive
+      if (match(Cmp, m_ICmp(Pred, m_V, m_Value(A))) &&
+          isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        if (RHSKnown.isZero() || RHSKnown.isNegative()) {
+          // We know that the sign bit is one.
+          Known.makeNegative();
+        }
+      }
+      break;
+    case ICmpInst::ICMP_ULE:
+      // assume(v <=_u c)
+      if (match(Cmp, m_ICmp(Pred, m_V, m_Value(A))) &&
+          isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        // Whatever high bits in c are zero are known to be zero.
+        Known.Zero.setHighBits(RHSKnown.countMinLeadingZeros());
+      }
+      break;
+    case ICmpInst::ICMP_ULT:
+      // assume(v <_u c)
+      if (match(Cmp, m_ICmp(Pred, m_V, m_Value(A))) &&
+          isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        KnownBits RHSKnown =
+            computeKnownBits(A, Depth+1, QueryNoAC).anyextOrTrunc(BitWidth);
+
+        // If the RHS is known zero, then this assumption must be wrong (nothing
+        // is unsigned less than zero). Signal a conflict and get out of here.
+        if (RHSKnown.isZero()) {
+          Known.Zero.setAllBits();
+          Known.One.setAllBits();
+          break;
+        }
+
+        // Whatever high bits in c are zero are known to be zero (if c is a power
+        // of 2, then one more).
+        if (isKnownToBeAPowerOfTwo(A, false, Depth + 1, QueryNoAC))
+          Known.Zero.setHighBits(RHSKnown.countMinLeadingZeros() + 1);
+        else
+          Known.Zero.setHighBits(RHSKnown.countMinLeadingZeros());
+      }
+      break;
+    case ICmpInst::ICMP_NE: {
+      // assume (v & b != 0) where b is a power of 2
+      const APInt *BPow2;
+      if (match(Cmp, m_ICmp(Pred, m_c_And(m_V, m_Power2(BPow2)), m_Zero())) &&
+          isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
+        Known.One |= BPow2->zextOrTrunc(BitWidth);
+      }
+    } break;
+    }
+  }
+
+  // If assumptions conflict with each other or previous known bits, then we
+  // have a logical fallacy. It's possible that the assumption is not reachable,
+  // so this isn't a real bug. On the other hand, the program may have undefined
+  // behavior, or we might have a bug in the compiler. We can't assert/crash, so
+  // clear out the known bits, try to warn the user, and hope for the best.
+  if (Known.Zero.intersects(Known.One)) {
+    Known.resetAll();
+
+    if (Q.ORE)
+      Q.ORE->emit([&]() {
+        auto *CxtI = const_cast<Instruction *>(Q.CxtI);
+        return OptimizationRemarkAnalysis("value-tracking", "BadAssumption",
+                                          CxtI)
+               << "Detected conflicting code assumptions. Program may "
+                  "have undefined behavior, or compiler may have "
+                  "internal error.";
+      });
+  }
+}
+
+/// Compute known bits from a shift operator, including those with a
+/// non-constant shift amount. Known is the output of this function. Known2 is a
+/// pre-allocated temporary with the same bit width as Known and on return
+/// contains the known bit of the shift value source. KF is an
+/// operator-specific function that, given the known-bits and a shift amount,
+/// compute the implied known-bits of the shift operator's result respectively
+/// for that shift amount. The results from calling KF are conservatively
+/// combined for all permitted shift amounts.
+static void computeKnownBitsFromShiftOperator(
+    const Operator *I, const APInt &DemandedElts, KnownBits &Known,
+    KnownBits &Known2, unsigned Depth, const Query &Q,
+    function_ref<KnownBits(const KnownBits &, const KnownBits &)> KF) {
+  unsigned BitWidth = Known.getBitWidth();
+  computeKnownBits(I->getOperand(0), DemandedElts, Known2, Depth + 1, Q);
+  computeKnownBits(I->getOperand(1), DemandedElts, Known, Depth + 1, Q);
+
+  // Note: We cannot use Known.Zero.getLimitedValue() here, because if
+  // BitWidth > 64 and any upper bits are known, we'll end up returning the
+  // limit value (which implies all bits are known).
+  uint64_t ShiftAmtKZ = Known.Zero.zextOrTrunc(64).getZExtValue();
+  uint64_t ShiftAmtKO = Known.One.zextOrTrunc(64).getZExtValue();
+  bool ShiftAmtIsConstant = Known.isConstant();
+  bool MaxShiftAmtIsOutOfRange = Known.getMaxValue().uge(BitWidth);
+
+  if (ShiftAmtIsConstant) {
+    Known = KF(Known2, Known);
+
+    // If the known bits conflict, this must be an overflowing left shift, so
+    // the shift result is poison. We can return anything we want. Choose 0 for
+    // the best folding opportunity.
+    if (Known.hasConflict())
+      Known.setAllZero();
+
+    return;
+  }
+
+  // If the shift amount could be greater than or equal to the bit-width of the
+  // LHS, the value could be poison, but bail out because the check below is
+  // expensive.
+  // TODO: Should we just carry on?
+  if (MaxShiftAmtIsOutOfRange) {
+    Known.resetAll();
+    return;
+  }
+
+  // It would be more-clearly correct to use the two temporaries for this
+  // calculation. Reusing the APInts here to prevent unnecessary allocations.
+  Known.resetAll();
+
+  // If we know the shifter operand is nonzero, we can sometimes infer more
+  // known bits. However this is expensive to compute, so be lazy about it and
+  // only compute it when absolutely necessary.
+  std::optional<bool> ShifterOperandIsNonZero;
+
+  // Early exit if we can't constrain any well-defined shift amount.
+  if (!(ShiftAmtKZ & (PowerOf2Ceil(BitWidth) - 1)) &&
+      !(ShiftAmtKO & (PowerOf2Ceil(BitWidth) - 1))) {
+    ShifterOperandIsNonZero =
+        isKnownNonZero(I->getOperand(1), DemandedElts, Depth + 1, Q);
+    if (!*ShifterOperandIsNonZero)
+      return;
+  }
+
+  Known.Zero.setAllBits();
+  Known.One.setAllBits();
+  for (unsigned ShiftAmt = 0; ShiftAmt < BitWidth; ++ShiftAmt) {
+    // Combine the shifted known input bits only for those shift amounts
+    // compatible with its known constraints.
+    if ((ShiftAmt & ~ShiftAmtKZ) != ShiftAmt)
+      continue;
+    if ((ShiftAmt | ShiftAmtKO) != ShiftAmt)
+      continue;
+    // If we know the shifter is nonzero, we may be able to infer more known
+    // bits. This check is sunk down as far as possible to avoid the expensive
+    // call to isKnownNonZero if the cheaper checks above fail.
+    if (ShiftAmt == 0) {
+      if (!ShifterOperandIsNonZero)
+        ShifterOperandIsNonZero =
+            isKnownNonZero(I->getOperand(1), DemandedElts, Depth + 1, Q);
+      if (*ShifterOperandIsNonZero)
+        continue;
+    }
+
+    Known = KnownBits::commonBits(
+        Known, KF(Known2, KnownBits::makeConstant(APInt(32, ShiftAmt))));
+  }
+
+  // If the known bits conflict, the result is poison. Return a 0 and hope the
+  // caller can further optimize that.
+  if (Known.hasConflict())
+    Known.setAllZero();
+}
+
+static void computeKnownBitsFromOperator(const Operator *I,
+                                         const APInt &DemandedElts,
+                                         KnownBits &Known, unsigned Depth,
+                                         const Query &Q) {
+  unsigned BitWidth = Known.getBitWidth();
+
+  KnownBits Known2(BitWidth);
+  switch (I->getOpcode()) {
+  default: break;
+  case Instruction::Load:
+    if (MDNode *MD =
+            Q.IIQ.getMetadata(cast<LoadInst>(I), LLVMContext::MD_range))
+      computeKnownBitsFromRangeMetadata(*MD, Known);
+    break;
+  case Instruction::And: {
+    // If either the LHS or the RHS are Zero, the result is zero.
+    computeKnownBits(I->getOperand(1), DemandedElts, Known, Depth + 1, Q);
+    computeKnownBits(I->getOperand(0), DemandedElts, Known2, Depth + 1, Q);
+
+    Known &= Known2;
+
+    // and(x, add (x, -1)) is a common idiom that always clears the low bit;
+    // here we handle the more general case of adding any odd number by
+    // matching the form add(x, add(x, y)) where y is odd.
+    // TODO: This could be generalized to clearing any bit set in y where the
+    // following bit is known to be unset in y.
+    Value *X = nullptr, *Y = nullptr;
+    if (!Known.Zero[0] && !Known.One[0] &&
+        match(I, m_c_BinOp(m_Value(X), m_Add(m_Deferred(X), m_Value(Y))))) {
+      Known2.resetAll();
+      computeKnownBits(Y, DemandedElts, Known2, Depth + 1, Q);
+      if (Known2.countMinTrailingOnes() > 0)
+        Known.Zero.setBit(0);
+    }
+    break;
+  }
+  case Instruction::Or:
+    computeKnownBits(I->getOperand(1), DemandedElts, Known, Depth + 1, Q);
+    computeKnownBits(I->getOperand(0), DemandedElts, Known2, Depth + 1, Q);
+
+    Known |= Known2;
+    break;
+  case Instruction::Xor:
+    computeKnownBits(I->getOperand(1), DemandedElts, Known, Depth + 1, Q);
+    computeKnownBits(I->getOperand(0), DemandedElts, Known2, Depth + 1, Q);
+
+    Known ^= Known2;
+    break;
+  case Instruction::Mul: {
+    bool NSW = Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(I));
+    computeKnownBitsMul(I->getOperand(0), I->getOperand(1), NSW, DemandedElts,
+                        Known, Known2, Depth, Q);
+    break;
+  }
+  case Instruction::UDiv: {
+    computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+    computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+    Known = KnownBits::udiv(Known, Known2);
+    break;
+  }
+  case Instruction::Select: {
+    const Value *LHS = nullptr, *RHS = nullptr;
+    SelectPatternFlavor SPF = matchSelectPattern(I, LHS, RHS).Flavor;
+    if (SelectPatternResult::isMinOrMax(SPF)) {
+      computeKnownBits(RHS, Known, Depth + 1, Q);
+      computeKnownBits(LHS, Known2, Depth + 1, Q);
+      switch (SPF) {
+      default:
+        llvm_unreachable("Unhandled select pattern flavor!");
+      case SPF_SMAX:
+        Known = KnownBits::smax(Known, Known2);
+        break;
+      case SPF_SMIN:
+        Known = KnownBits::smin(Known, Known2);
+        break;
+      case SPF_UMAX:
+        Known = KnownBits::umax(Known, Known2);
+        break;
+      case SPF_UMIN:
+        Known = KnownBits::umin(Known, Known2);
+        break;
+      }
+      break;
+    }
+
+    computeKnownBits(I->getOperand(2), Known, Depth + 1, Q);
+    computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+
+    // Only known if known in both the LHS and RHS.
+    Known = KnownBits::commonBits(Known, Known2);
+
+    if (SPF == SPF_ABS) {
+      // RHS from matchSelectPattern returns the negation part of abs pattern.
+      // If the negate has an NSW flag we can assume the sign bit of the result
+      // will be 0 because that makes abs(INT_MIN) undefined.
+      if (match(RHS, m_Neg(m_Specific(LHS))) &&
+          Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(RHS)))
+        Known.Zero.setSignBit();
+    }
+
+    break;
+  }
+  case Instruction::FPTrunc:
+  case Instruction::FPExt:
+  case Instruction::FPToUI:
+  case Instruction::FPToSI:
+  case Instruction::SIToFP:
+  case Instruction::UIToFP:
+    break; // Can't work with floating point.
+  case Instruction::PtrToInt:
+  case Instruction::IntToPtr:
+    // Fall through and handle them the same as zext/trunc.
+    [[fallthrough]];
+  case Instruction::ZExt:
+  case Instruction::Trunc: {
+    Type *SrcTy = I->getOperand(0)->getType();
+
+    unsigned SrcBitWidth;
+    // Note that we handle pointer operands here because of inttoptr/ptrtoint
+    // which fall through here.
+    Type *ScalarTy = SrcTy->getScalarType();
+    SrcBitWidth = ScalarTy->isPointerTy() ?
+      Q.DL.getPointerTypeSizeInBits(ScalarTy) :
+      Q.DL.getTypeSizeInBits(ScalarTy);
+
+    assert(SrcBitWidth && "SrcBitWidth can't be zero");
+    Known = Known.anyextOrTrunc(SrcBitWidth);
+    computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+    Known = Known.zextOrTrunc(BitWidth);
+    break;
+  }
+  case Instruction::BitCast: {
+    Type *SrcTy = I->getOperand(0)->getType();
+    if (SrcTy->isIntOrPtrTy() &&
+        // TODO: For now, not handling conversions like:
+        // (bitcast i64 %x to <2 x i32>)
+        !I->getType()->isVectorTy()) {
+      computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+      break;
+    }
+
+    // Handle cast from vector integer type to scalar or vector integer.
+    auto *SrcVecTy = dyn_cast<FixedVectorType>(SrcTy);
+    if (!SrcVecTy || !SrcVecTy->getElementType()->isIntegerTy() ||
+        !I->getType()->isIntOrIntVectorTy() ||
+        isa<ScalableVectorType>(I->getType()))
+      break;
+
+    // Look through a cast from narrow vector elements to wider type.
+    // Examples: v4i32 -> v2i64, v3i8 -> v24
+    unsigned SubBitWidth = SrcVecTy->getScalarSizeInBits();
+    if (BitWidth % SubBitWidth == 0) {
+      // Known bits are automatically intersected across demanded elements of a
+      // vector. So for example, if a bit is computed as known zero, it must be
+      // zero across all demanded elements of the vector.
+      //
+      // For this bitcast, each demanded element of the output is sub-divided
+      // across a set of smaller vector elements in the source vector. To get
+      // the known bits for an entire element of the output, compute the known
+      // bits for each sub-element sequentially. This is done by shifting the
+      // one-set-bit demanded elements parameter across the sub-elements for
+      // consecutive calls to computeKnownBits. We are using the demanded
+      // elements parameter as a mask operator.
+      //
+      // The known bits of each sub-element are then inserted into place
+      // (dependent on endian) to form the full result of known bits.
+      unsigned NumElts = DemandedElts.getBitWidth();
+      unsigned SubScale = BitWidth / SubBitWidth;
+      APInt SubDemandedElts = APInt::getZero(NumElts * SubScale);
+      for (unsigned i = 0; i != NumElts; ++i) {
+        if (DemandedElts[i])
+          SubDemandedElts.setBit(i * SubScale);
+      }
+
+      KnownBits KnownSrc(SubBitWidth);
+      for (unsigned i = 0; i != SubScale; ++i) {
+        computeKnownBits(I->getOperand(0), SubDemandedElts.shl(i), KnownSrc,
+                         Depth + 1, Q);
+        unsigned ShiftElt = Q.DL.isLittleEndian() ? i : SubScale - 1 - i;
+        Known.insertBits(KnownSrc, ShiftElt * SubBitWidth);
+      }
+    }
+    break;
+  }
+  case Instruction::SExt: {
+    // Compute the bits in the result that are not present in the input.
+    unsigned SrcBitWidth = I->getOperand(0)->getType()->getScalarSizeInBits();
+
+    Known = Known.trunc(SrcBitWidth);
+    computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+    // If the sign bit of the input is known set or clear, then we know the
+    // top bits of the result.
+    Known = Known.sext(BitWidth);
+    break;
+  }
+  case Instruction::Shl: {
+    bool NSW = Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(I));
+    auto KF = [NSW](const KnownBits &KnownVal, const KnownBits &KnownAmt) {
+      KnownBits Result = KnownBits::shl(KnownVal, KnownAmt);
+      // If this shift has "nsw" keyword, then the result is either a poison
+      // value or has the same sign bit as the first operand.
+      if (NSW) {
+        if (KnownVal.Zero.isSignBitSet())
+          Result.Zero.setSignBit();
+        if (KnownVal.One.isSignBitSet())
+          Result.One.setSignBit();
+      }
+      return Result;
+    };
+    computeKnownBitsFromShiftOperator(I, DemandedElts, Known, Known2, Depth, Q,
+                                      KF);
+    // Trailing zeros of a right-shifted constant never decrease.
+    const APInt *C;
+    if (match(I->getOperand(0), m_APInt(C)))
+      Known.Zero.setLowBits(C->countTrailingZeros());
+    break;
+  }
+  case Instruction::LShr: {
+    auto KF = [](const KnownBits &KnownVal, const KnownBits &KnownAmt) {
+      return KnownBits::lshr(KnownVal, KnownAmt);
+    };
+    computeKnownBitsFromShiftOperator(I, DemandedElts, Known, Known2, Depth, Q,
+                                      KF);
+    // Leading zeros of a left-shifted constant never decrease.
+    const APInt *C;
+    if (match(I->getOperand(0), m_APInt(C)))
+      Known.Zero.setHighBits(C->countLeadingZeros());
+    break;
+  }
+  case Instruction::AShr: {
+    auto KF = [](const KnownBits &KnownVal, const KnownBits &KnownAmt) {
+      return KnownBits::ashr(KnownVal, KnownAmt);
+    };
+    computeKnownBitsFromShiftOperator(I, DemandedElts, Known, Known2, Depth, Q,
+                                      KF);
+    break;
+  }
+  case Instruction::Sub: {
+    bool NSW = Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(I));
+    computeKnownBitsAddSub(false, I->getOperand(0), I->getOperand(1), NSW,
+                           DemandedElts, Known, Known2, Depth, Q);
+    break;
+  }
+  case Instruction::Add: {
+    bool NSW = Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(I));
+    computeKnownBitsAddSub(true, I->getOperand(0), I->getOperand(1), NSW,
+                           DemandedElts, Known, Known2, Depth, Q);
+    break;
+  }
+  case Instruction::SRem:
+    computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+    computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+    Known = KnownBits::srem(Known, Known2);
+    break;
+
+  case Instruction::URem:
+    computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+    computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+    Known = KnownBits::urem(Known, Known2);
+    break;
+  case Instruction::Alloca:
+    Known.Zero.setLowBits(Log2(cast<AllocaInst>(I)->getAlign()));
+    break;
+  case Instruction::GetElementPtr: {
+    // Analyze all of the subscripts of this getelementptr instruction
+    // to determine if we can prove known low zero bits.
+    computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+    // Accumulate the constant indices in a separate variable
+    // to minimize the number of calls to computeForAddSub.
+    APInt AccConstIndices(BitWidth, 0, /*IsSigned*/ true);
+
+    gep_type_iterator GTI = gep_type_begin(I);
+    for (unsigned i = 1, e = I->getNumOperands(); i != e; ++i, ++GTI) {
+      // TrailZ can only become smaller, short-circuit if we hit zero.
+      if (Known.isUnknown())
+        break;
+
+      Value *Index = I->getOperand(i);
+
+      // Handle case when index is zero.
+      Constant *CIndex = dyn_cast<Constant>(Index);
+      if (CIndex && CIndex->isZeroValue())
+        continue;
+
+      if (StructType *STy = GTI.getStructTypeOrNull()) {
+        // Handle struct member offset arithmetic.
+
+        assert(CIndex &&
+               "Access to structure field must be known at compile time");
+
+        if (CIndex->getType()->isVectorTy())
+          Index = CIndex->getSplatValue();
+
+        unsigned Idx = cast<ConstantInt>(Index)->getZExtValue();
+        const StructLayout *SL = Q.DL.getStructLayout(STy);
+        uint64_t Offset = SL->getElementOffset(Idx);
+        AccConstIndices += Offset;
+        continue;
+      }
+
+      // Handle array index arithmetic.
+      Type *IndexedTy = GTI.getIndexedType();
+      if (!IndexedTy->isSized()) {
+        Known.resetAll();
+        break;
+      }
+
+      unsigned IndexBitWidth = Index->getType()->getScalarSizeInBits();
+      KnownBits IndexBits(IndexBitWidth);
+      computeKnownBits(Index, IndexBits, Depth + 1, Q);
+      TypeSize IndexTypeSize = Q.DL.getTypeAllocSize(IndexedTy);
+      uint64_t TypeSizeInBytes = IndexTypeSize.getKnownMinValue();
+      KnownBits ScalingFactor(IndexBitWidth);
+      // Multiply by current sizeof type.
+      // &A[i] == A + i * sizeof(*A[i]).
+      if (IndexTypeSize.isScalable()) {
+        // For scalable types the only thing we know about sizeof is
+        // that this is a multiple of the minimum size.
+        ScalingFactor.Zero.setLowBits(countTrailingZeros(TypeSizeInBytes));
+      } else if (IndexBits.isConstant()) {
+        APInt IndexConst = IndexBits.getConstant();
+        APInt ScalingFactor(IndexBitWidth, TypeSizeInBytes);
+        IndexConst *= ScalingFactor;
+        AccConstIndices += IndexConst.sextOrTrunc(BitWidth);
+        continue;
+      } else {
+        ScalingFactor =
+            KnownBits::makeConstant(APInt(IndexBitWidth, TypeSizeInBytes));
+      }
+      IndexBits = KnownBits::mul(IndexBits, ScalingFactor);
+
+      // If the offsets have a different width from the pointer, according
+      // to the language reference we need to sign-extend or truncate them
+      // to the width of the pointer.
+      IndexBits = IndexBits.sextOrTrunc(BitWidth);
+
+      // Note that inbounds does *not* guarantee nsw for the addition, as only
+      // the offset is signed, while the base address is unsigned.
+      Known = KnownBits::computeForAddSub(
+          /*Add=*/true, /*NSW=*/false, Known, IndexBits);
+    }
+    if (!Known.isUnknown() && !AccConstIndices.isZero()) {
+      KnownBits Index = KnownBits::makeConstant(AccConstIndices);
+      Known = KnownBits::computeForAddSub(
+          /*Add=*/true, /*NSW=*/false, Known, Index);
+    }
+    break;
+  }
+  case Instruction::PHI: {
+    const PHINode *P = cast<PHINode>(I);
+    BinaryOperator *BO = nullptr;
+    Value *R = nullptr, *L = nullptr;
+    if (matchSimpleRecurrence(P, BO, R, L)) {
+      // Handle the case of a simple two-predecessor recurrence PHI.
+      // There's a lot more that could theoretically be done here, but
+      // this is sufficient to catch some interesting cases.
+      unsigned Opcode = BO->getOpcode();
+
+      // If this is a shift recurrence, we know the bits being shifted in.
+      // We can combine that with information about the start value of the
+      // recurrence to conclude facts about the result.
+      if ((Opcode == Instruction::LShr || Opcode == Instruction::AShr ||
+           Opcode == Instruction::Shl) &&
+          BO->getOperand(0) == I) {
+
+        // We have matched a recurrence of the form:
+        // %iv = [R, %entry], [%iv.next, %backedge]
+        // %iv.next = shift_op %iv, L
+
+        // Recurse with the phi context to avoid concern about whether facts
+        // inferred hold at original context instruction.  TODO: It may be
+        // correct to use the original context.  IF warranted, explore and
+        // add sufficient tests to cover.
+        Query RecQ = Q;
+        RecQ.CxtI = P;
+        computeKnownBits(R, DemandedElts, Known2, Depth + 1, RecQ);
+        switch (Opcode) {
+        case Instruction::Shl:
+          // A shl recurrence will only increase the tailing zeros
+          Known.Zero.setLowBits(Known2.countMinTrailingZeros());
+          break;
+        case Instruction::LShr:
+          // A lshr recurrence will preserve the leading zeros of the
+          // start value
+          Known.Zero.setHighBits(Known2.countMinLeadingZeros());
+          break;
+        case Instruction::AShr:
+          // An ashr recurrence will extend the initial sign bit
+          Known.Zero.setHighBits(Known2.countMinLeadingZeros());
+          Known.One.setHighBits(Known2.countMinLeadingOnes());
+          break;
+        };
+      }
+
+      // Check for operations that have the property that if
+      // both their operands have low zero bits, the result
+      // will have low zero bits.
+      if (Opcode == Instruction::Add ||
+          Opcode == Instruction::Sub ||
+          Opcode == Instruction::And ||
+          Opcode == Instruction::Or ||
+          Opcode == Instruction::Mul) {
+        // Change the context instruction to the "edge" that flows into the
+        // phi. This is important because that is where the value is actually
+        // "evaluated" even though it is used later somewhere else. (see also
+        // D69571).
+        Query RecQ = Q;
+
+        unsigned OpNum = P->getOperand(0) == R ? 0 : 1;
+        Instruction *RInst = P->getIncomingBlock(OpNum)->getTerminator();
+        Instruction *LInst = P->getIncomingBlock(1-OpNum)->getTerminator();
+
+        // Ok, we have a PHI of the form L op= R. Check for low
+        // zero bits.
+        RecQ.CxtI = RInst;
+        computeKnownBits(R, Known2, Depth + 1, RecQ);
+
+        // We need to take the minimum number of known bits
+        KnownBits Known3(BitWidth);
+        RecQ.CxtI = LInst;
+        computeKnownBits(L, Known3, Depth + 1, RecQ);
+
+        Known.Zero.setLowBits(std::min(Known2.countMinTrailingZeros(),
+                                       Known3.countMinTrailingZeros()));
+
+        auto *OverflowOp = dyn_cast<OverflowingBinaryOperator>(BO);
+        if (OverflowOp && Q.IIQ.hasNoSignedWrap(OverflowOp)) {
+          // If initial value of recurrence is nonnegative, and we are adding
+          // a nonnegative number with nsw, the result can only be nonnegative
+          // or poison value regardless of the number of times we execute the
+          // add in phi recurrence. If initial value is negative and we are
+          // adding a negative number with nsw, the result can only be
+          // negative or poison value. Similar arguments apply to sub and mul.
+          //
+          // (add non-negative, non-negative) --> non-negative
+          // (add negative, negative) --> negative
+          if (Opcode == Instruction::Add) {
+            if (Known2.isNonNegative() && Known3.isNonNegative())
+              Known.makeNonNegative();
+            else if (Known2.isNegative() && Known3.isNegative())
+              Known.makeNegative();
+          }
+
+          // (sub nsw non-negative, negative) --> non-negative
+          // (sub nsw negative, non-negative) --> negative
+          else if (Opcode == Instruction::Sub && BO->getOperand(0) == I) {
+            if (Known2.isNonNegative() && Known3.isNegative())
+              Known.makeNonNegative();
+            else if (Known2.isNegative() && Known3.isNonNegative())
+              Known.makeNegative();
+          }
+
+          // (mul nsw non-negative, non-negative) --> non-negative
+          else if (Opcode == Instruction::Mul && Known2.isNonNegative() &&
+                   Known3.isNonNegative())
+            Known.makeNonNegative();
+        }
+
+        break;
+      }
+    }
+
+    // Unreachable blocks may have zero-operand PHI nodes.
+    if (P->getNumIncomingValues() == 0)
+      break;
+
+    // Otherwise take the unions of the known bit sets of the operands,
+    // taking conservative care to avoid excessive recursion.
+    if (Depth < MaxAnalysisRecursionDepth - 1 && !Known.Zero && !Known.One) {
+      // Skip if every incoming value references to ourself.
+      if (isa_and_nonnull<UndefValue>(P->hasConstantValue()))
+        break;
+
+      Known.Zero.setAllBits();
+      Known.One.setAllBits();
+      for (unsigned u = 0, e = P->getNumIncomingValues(); u < e; ++u) {
+        Value *IncValue = P->getIncomingValue(u);
+        // Skip direct self references.
+        if (IncValue == P) continue;
+
+        // Change the context instruction to the "edge" that flows into the
+        // phi. This is important because that is where the value is actually
+        // "evaluated" even though it is used later somewhere else. (see also
+        // D69571).
+        Query RecQ = Q;
+        RecQ.CxtI = P->getIncomingBlock(u)->getTerminator();
+
+        Known2 = KnownBits(BitWidth);
+
+        // Recurse, but cap the recursion to one level, because we don't
+        // want to waste time spinning around in loops.
+        computeKnownBits(IncValue, Known2, MaxAnalysisRecursionDepth - 1, RecQ);
+
+        // If this failed, see if we can use a conditional branch into the phi
+        // to help us determine the range of the value.
+        if (Known2.isUnknown()) {
+          ICmpInst::Predicate Pred;
+          const APInt *RHSC;
+          BasicBlock *TrueSucc, *FalseSucc;
+          // TODO: Use RHS Value and compute range from its known bits.
+          if (match(RecQ.CxtI,
+                    m_Br(m_c_ICmp(Pred, m_Specific(IncValue), m_APInt(RHSC)),
+                         m_BasicBlock(TrueSucc), m_BasicBlock(FalseSucc)))) {
+            // Check for cases of duplicate successors.
+            if ((TrueSucc == P->getParent()) != (FalseSucc == P->getParent())) {
+              // If we're using the false successor, invert the predicate.
+              if (FalseSucc == P->getParent())
+                Pred = CmpInst::getInversePredicate(Pred);
+
+              switch (Pred) {
+              case CmpInst::Predicate::ICMP_EQ:
+                Known2 = KnownBits::makeConstant(*RHSC);
+                break;
+              case CmpInst::Predicate::ICMP_ULE:
+                Known2.Zero.setHighBits(RHSC->countLeadingZeros());
+                break;
+              case CmpInst::Predicate::ICMP_ULT:
+                Known2.Zero.setHighBits((*RHSC - 1).countLeadingZeros());
+                break;
+              default:
+                // TODO - add additional integer predicate handling.
+                break;
+              }
+            }
+          }
+        }
+
+        Known = KnownBits::commonBits(Known, Known2);
+        // If all bits have been ruled out, there's no need to check
+        // more operands.
+        if (Known.isUnknown())
+          break;
+      }
+    }
+    break;
+  }
+  case Instruction::Call:
+  case Instruction::Invoke:
+    // If range metadata is attached to this call, set known bits from that,
+    // and then intersect with known bits based on other properties of the
+    // function.
+    if (MDNode *MD =
+            Q.IIQ.getMetadata(cast<Instruction>(I), LLVMContext::MD_range))
+      computeKnownBitsFromRangeMetadata(*MD, Known);
+    if (const Value *RV = cast<CallBase>(I)->getReturnedArgOperand()) {
+      computeKnownBits(RV, Known2, Depth + 1, Q);
+      Known.Zero |= Known2.Zero;
+      Known.One |= Known2.One;
+    }
+    if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
+      switch (II->getIntrinsicID()) {
+      default: break;
+      case Intrinsic::abs: {
+        computeKnownBits(I->getOperand(0), Known2, Depth + 1, Q);
+        bool IntMinIsPoison = match(II->getArgOperand(1), m_One());
+        Known = Known2.abs(IntMinIsPoison);
+        break;
+      }
+      case Intrinsic::bitreverse:
+        computeKnownBits(I->getOperand(0), DemandedElts, Known2, Depth + 1, Q);
+        Known.Zero |= Known2.Zero.reverseBits();
+        Known.One |= Known2.One.reverseBits();
+        break;
+      case Intrinsic::bswap:
+        computeKnownBits(I->getOperand(0), DemandedElts, Known2, Depth + 1, Q);
+        Known.Zero |= Known2.Zero.byteSwap();
+        Known.One |= Known2.One.byteSwap();
+        break;
+      case Intrinsic::ctlz: {
+        computeKnownBits(I->getOperand(0), Known2, Depth + 1, Q);
+        // If we have a known 1, its position is our upper bound.
+        unsigned PossibleLZ = Known2.countMaxLeadingZeros();
+        // If this call is poison for 0 input, the result will be less than 2^n.
+        if (II->getArgOperand(1) == ConstantInt::getTrue(II->getContext()))
+          PossibleLZ = std::min(PossibleLZ, BitWidth - 1);
+        unsigned LowBits = llvm::bit_width(PossibleLZ);
+        Known.Zero.setBitsFrom(LowBits);
+        break;
+      }
+      case Intrinsic::cttz: {
+        computeKnownBits(I->getOperand(0), Known2, Depth + 1, Q);
+        // If we have a known 1, its position is our upper bound.
+        unsigned PossibleTZ = Known2.countMaxTrailingZeros();
+        // If this call is poison for 0 input, the result will be less than 2^n.
+        if (II->getArgOperand(1) == ConstantInt::getTrue(II->getContext()))
+          PossibleTZ = std::min(PossibleTZ, BitWidth - 1);
+        unsigned LowBits = llvm::bit_width(PossibleTZ);
+        Known.Zero.setBitsFrom(LowBits);
+        break;
+      }
+      case Intrinsic::ctpop: {
+        computeKnownBits(I->getOperand(0), Known2, Depth + 1, Q);
+        // We can bound the space the count needs.  Also, bits known to be zero
+        // can't contribute to the population.
+        unsigned BitsPossiblySet = Known2.countMaxPopulation();
+        unsigned LowBits = llvm::bit_width(BitsPossiblySet);
+        Known.Zero.setBitsFrom(LowBits);
+        // TODO: we could bound KnownOne using the lower bound on the number
+        // of bits which might be set provided by popcnt KnownOne2.
+        break;
+      }
+      case Intrinsic::fshr:
+      case Intrinsic::fshl: {
+        const APInt *SA;
+        if (!match(I->getOperand(2), m_APInt(SA)))
+          break;
+
+        // Normalize to funnel shift left.
+        uint64_t ShiftAmt = SA->urem(BitWidth);
+        if (II->getIntrinsicID() == Intrinsic::fshr)
+          ShiftAmt = BitWidth - ShiftAmt;
+
+        KnownBits Known3(BitWidth);
+        computeKnownBits(I->getOperand(0), Known2, Depth + 1, Q);
+        computeKnownBits(I->getOperand(1), Known3, Depth + 1, Q);
+
+        Known.Zero =
+            Known2.Zero.shl(ShiftAmt) | Known3.Zero.lshr(BitWidth - ShiftAmt);
+        Known.One =
+            Known2.One.shl(ShiftAmt) | Known3.One.lshr(BitWidth - ShiftAmt);
+        break;
+      }
+      case Intrinsic::uadd_sat:
+      case Intrinsic::usub_sat: {
+        bool IsAdd = II->getIntrinsicID() == Intrinsic::uadd_sat;
+        computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+        computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+
+        // Add: Leading ones of either operand are preserved.
+        // Sub: Leading zeros of LHS and leading ones of RHS are preserved
+        // as leading zeros in the result.
+        unsigned LeadingKnown;
+        if (IsAdd)
+          LeadingKnown = std::max(Known.countMinLeadingOnes(),
+                                  Known2.countMinLeadingOnes());
+        else
+          LeadingKnown = std::max(Known.countMinLeadingZeros(),
+                                  Known2.countMinLeadingOnes());
+
+        Known = KnownBits::computeForAddSub(
+            IsAdd, /* NSW */ false, Known, Known2);
+
+        // We select between the operation result and all-ones/zero
+        // respectively, so we can preserve known ones/zeros.
+        if (IsAdd) {
+          Known.One.setHighBits(LeadingKnown);
+          Known.Zero.clearAllBits();
+        } else {
+          Known.Zero.setHighBits(LeadingKnown);
+          Known.One.clearAllBits();
+        }
+        break;
+      }
+      case Intrinsic::umin:
+        computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+        computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+        Known = KnownBits::umin(Known, Known2);
+        break;
+      case Intrinsic::umax:
+        computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+        computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+        Known = KnownBits::umax(Known, Known2);
+        break;
+      case Intrinsic::smin:
+        computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+        computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+        Known = KnownBits::smin(Known, Known2);
+        break;
+      case Intrinsic::smax:
+        computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+        computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
+        Known = KnownBits::smax(Known, Known2);
+        break;
+      case Intrinsic::x86_sse42_crc32_64_64:
+        Known.Zero.setBitsFrom(32);
+        break;
+      case Intrinsic::riscv_vsetvli:
+      case Intrinsic::riscv_vsetvlimax:
+        // Assume that VL output is positive and would fit in an int32_t.
+        // TODO: VLEN might be capped at 16 bits in a future V spec update.
+        if (BitWidth >= 32)
+          Known.Zero.setBitsFrom(31);
+        break;
+      case Intrinsic::vscale: {
+        if (!II->getParent() || !II->getFunction() ||
+            !II->getFunction()->hasFnAttribute(Attribute::VScaleRange))
+          break;
+
+        auto Attr = II->getFunction()->getFnAttribute(Attribute::VScaleRange);
+        std::optional<unsigned> VScaleMax = Attr.getVScaleRangeMax();
+
+        if (!VScaleMax)
+          break;
+
+        unsigned VScaleMin = Attr.getVScaleRangeMin();
+
+        // If vscale min = max then we know the exact value at compile time
+        // and hence we know the exact bits.
+        if (VScaleMin == VScaleMax) {
+          Known.One = VScaleMin;
+          Known.Zero = VScaleMin;
+          Known.Zero.flipAllBits();
+          break;
+        }
+
+        unsigned FirstZeroHighBit = llvm::bit_width(*VScaleMax);
+        if (FirstZeroHighBit < BitWidth)
+          Known.Zero.setBitsFrom(FirstZeroHighBit);
+
+        break;
+      }
+      }
+    }
+    break;
+  case Instruction::ShuffleVector: {
+    auto *Shuf = dyn_cast<ShuffleVectorInst>(I);
+    // FIXME: Do we need to handle ConstantExpr involving shufflevectors?
+    if (!Shuf) {
+      Known.resetAll();
+      return;
+    }
+    // For undef elements, we don't know anything about the common state of
+    // the shuffle result.
+    APInt DemandedLHS, DemandedRHS;
+    if (!getShuffleDemandedElts(Shuf, DemandedElts, DemandedLHS, DemandedRHS)) {
+      Known.resetAll();
+      return;
+    }
+    Known.One.setAllBits();
+    Known.Zero.setAllBits();
+    if (!!DemandedLHS) {
+      const Value *LHS = Shuf->getOperand(0);
+      computeKnownBits(LHS, DemandedLHS, Known, Depth + 1, Q);
+      // If we don't know any bits, early out.
+      if (Known.isUnknown())
+        break;
+    }
+    if (!!DemandedRHS) {
+      const Value *RHS = Shuf->getOperand(1);
+      computeKnownBits(RHS, DemandedRHS, Known2, Depth + 1, Q);
+      Known = KnownBits::commonBits(Known, Known2);
+    }
+    break;
+  }
+  case Instruction::InsertElement: {
+    if (isa<ScalableVectorType>(I->getType())) {
+      Known.resetAll();
+      return;
+    }
+    const Value *Vec = I->getOperand(0);
+    const Value *Elt = I->getOperand(1);
+    auto *CIdx = dyn_cast<ConstantInt>(I->getOperand(2));
+    // Early out if the index is non-constant or out-of-range.
+    unsigned NumElts = DemandedElts.getBitWidth();
+    if (!CIdx || CIdx->getValue().uge(NumElts)) {
+      Known.resetAll();
+      return;
+    }
+    Known.One.setAllBits();
+    Known.Zero.setAllBits();
+    unsigned EltIdx = CIdx->getZExtValue();
+    // Do we demand the inserted element?
+    if (DemandedElts[EltIdx]) {
+      computeKnownBits(Elt, Known, Depth + 1, Q);
+      // If we don't know any bits, early out.
+      if (Known.isUnknown())
+        break;
+    }
+    // We don't need the base vector element that has been inserted.
+    APInt DemandedVecElts = DemandedElts;
+    DemandedVecElts.clearBit(EltIdx);
+    if (!!DemandedVecElts) {
+      computeKnownBits(Vec, DemandedVecElts, Known2, Depth + 1, Q);
+      Known = KnownBits::commonBits(Known, Known2);
+    }
+    break;
+  }
+  case Instruction::ExtractElement: {
+    // Look through extract element. If the index is non-constant or
+    // out-of-range demand all elements, otherwise just the extracted element.
+    const Value *Vec = I->getOperand(0);
+    const Value *Idx = I->getOperand(1);
+    auto *CIdx = dyn_cast<ConstantInt>(Idx);
+    if (isa<ScalableVectorType>(Vec->getType())) {
+      // FIXME: there's probably *something* we can do with scalable vectors
+      Known.resetAll();
+      break;
+    }
+    unsigned NumElts = cast<FixedVectorType>(Vec->getType())->getNumElements();
+    APInt DemandedVecElts = APInt::getAllOnes(NumElts);
+    if (CIdx && CIdx->getValue().ult(NumElts))
+      DemandedVecElts = APInt::getOneBitSet(NumElts, CIdx->getZExtValue());
+    computeKnownBits(Vec, DemandedVecElts, Known, Depth + 1, Q);
+    break;
+  }
+  case Instruction::ExtractValue:
+    if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I->getOperand(0))) {
+      const ExtractValueInst *EVI = cast<ExtractValueInst>(I);
+      if (EVI->getNumIndices() != 1) break;
+      if (EVI->getIndices()[0] == 0) {
+        switch (II->getIntrinsicID()) {
+        default: break;
+        case Intrinsic::uadd_with_overflow:
+        case Intrinsic::sadd_with_overflow:
+          computeKnownBitsAddSub(true, II->getArgOperand(0),
+                                 II->getArgOperand(1), false, DemandedElts,
+                                 Known, Known2, Depth, Q);
+          break;
+        case Intrinsic::usub_with_overflow:
+        case Intrinsic::ssub_with_overflow:
+          computeKnownBitsAddSub(false, II->getArgOperand(0),
+                                 II->getArgOperand(1), false, DemandedElts,
+                                 Known, Known2, Depth, Q);
+          break;
+        case Intrinsic::umul_with_overflow:
+        case Intrinsic::smul_with_overflow:
+          computeKnownBitsMul(II->getArgOperand(0), II->getArgOperand(1), false,
+                              DemandedElts, Known, Known2, Depth, Q);
+          break;
+        }
+      }
+    }
+    break;
+  case Instruction::Freeze:
+    if (isGuaranteedNotToBePoison(I->getOperand(0), Q.AC, Q.CxtI, Q.DT,
+                                  Depth + 1))
+      computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
+    break;
+  }
+}
+
+/// Determine which bits of V are known to be either zero or one and return
+/// them.
+KnownBits computeKnownBits(const Value *V, const APInt &DemandedElts,
+                           unsigned Depth, const Query &Q) {
+  KnownBits Known(getBitWidth(V->getType(), Q.DL));
+  computeKnownBits(V, DemandedElts, Known, Depth, Q);
+  return Known;
+}
+
+/// Determine which bits of V are known to be either zero or one and return
+/// them.
+KnownBits computeKnownBits(const Value *V, unsigned Depth, const Query &Q) {
+  KnownBits Known(getBitWidth(V->getType(), Q.DL));
+  computeKnownBits(V, Known, Depth, Q);
+  return Known;
+}
+
+/// Determine which bits of V are known to be either zero or one and return
+/// them in the Known bit set.
+///
+/// NOTE: we cannot consider 'undef' to be "IsZero" here.  The problem is that
+/// we cannot optimize based on the assumption that it is zero without changing
+/// it to be an explicit zero.  If we don't change it to zero, other code could
+/// optimized based on the contradictory assumption that it is non-zero.
+/// Because instcombine aggressively folds operations with undef args anyway,
+/// this won't lose us code quality.
+///
+/// This function is defined on values with integer type, values with pointer
+/// type, and vectors of integers.  In the case
+/// where V is a vector, known zero, and known one values are the
+/// same width as the vector element, and the bit is set only if it is true
+/// for all of the demanded elements in the vector specified by DemandedElts.
+void computeKnownBits(const Value *V, const APInt &DemandedElts,
+                      KnownBits &Known, unsigned Depth, const Query &Q) {
+  if (!DemandedElts) {
+    // No demanded elts, better to assume we don't know anything.
+    Known.resetAll();
+    return;
+  }
+
+  assert(V && "No Value?");
+  assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
+
+#ifndef NDEBUG
+  Type *Ty = V->getType();
+  unsigned BitWidth = Known.getBitWidth();
+
+  assert((Ty->isIntOrIntVectorTy(BitWidth) || Ty->isPtrOrPtrVectorTy()) &&
+         "Not integer or pointer type!");
+
+  if (auto *FVTy = dyn_cast<FixedVectorType>(Ty)) {
+    assert(
+        FVTy->getNumElements() == DemandedElts.getBitWidth() &&
+        "DemandedElt width should equal the fixed vector number of elements");
+  } else {
+    assert(DemandedElts == APInt(1, 1) &&
+           "DemandedElt width should be 1 for scalars or scalable vectors");
+  }
+
+  Type *ScalarTy = Ty->getScalarType();
+  if (ScalarTy->isPointerTy()) {
+    assert(BitWidth == Q.DL.getPointerTypeSizeInBits(ScalarTy) &&
+           "V and Known should have same BitWidth");
+  } else {
+    assert(BitWidth == Q.DL.getTypeSizeInBits(ScalarTy) &&
+           "V and Known should have same BitWidth");
+  }
+#endif
+
+  const APInt *C;
+  if (match(V, m_APInt(C))) {
+    // We know all of the bits for a scalar constant or a splat vector constant!
+    Known = KnownBits::makeConstant(*C);
+    return;
+  }
+  // Null and aggregate-zero are all-zeros.
+  if (isa<ConstantPointerNull>(V) || isa<ConstantAggregateZero>(V)) {
+    Known.setAllZero();
+    return;
+  }
+  // Handle a constant vector by taking the intersection of the known bits of
+  // each element.
+  if (const ConstantDataVector *CDV = dyn_cast<ConstantDataVector>(V)) {
+    assert(!isa<ScalableVectorType>(V->getType()));
+    // We know that CDV must be a vector of integers. Take the intersection of
+    // each element.
+    Known.Zero.setAllBits(); Known.One.setAllBits();
+    for (unsigned i = 0, e = CDV->getNumElements(); i != e; ++i) {
+      if (!DemandedElts[i])
+        continue;
+      APInt Elt = CDV->getElementAsAPInt(i);
+      Known.Zero &= ~Elt;
+      Known.One &= Elt;
+    }
+    return;
+  }
+
+  if (const auto *CV = dyn_cast<ConstantVector>(V)) {
+    assert(!isa<ScalableVectorType>(V->getType()));
+    // We know that CV must be a vector of integers. Take the intersection of
+    // each element.
+    Known.Zero.setAllBits(); Known.One.setAllBits();
+    for (unsigned i = 0, e = CV->getNumOperands(); i != e; ++i) {
+      if (!DemandedElts[i])
+        continue;
+      Constant *Element = CV->getAggregateElement(i);
+      auto *ElementCI = dyn_cast_or_null<ConstantInt>(Element);
+      if (!ElementCI) {
+        Known.resetAll();
+        return;
+      }
+      const APInt &Elt = ElementCI->getValue();
+      Known.Zero &= ~Elt;
+      Known.One &= Elt;
+    }
+    return;
+  }
+
+  // Start out not knowing anything.
+  Known.resetAll();
+
+  // We can't imply anything about undefs.
+  if (isa<UndefValue>(V))
+    return;
+
+  // There's no point in looking through other users of ConstantData for
+  // assumptions.  Confirm that we've handled them all.
+  assert(!isa<ConstantData>(V) && "Unhandled constant data!");
+
+  // All recursive calls that increase depth must come after this.
+  if (Depth == MaxAnalysisRecursionDepth)
+    return;
+
+  // A weak GlobalAlias is totally unknown. A non-weak GlobalAlias has
+  // the bits of its aliasee.
+  if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
+    if (!GA->isInterposable())
+      computeKnownBits(GA->getAliasee(), Known, Depth + 1, Q);
+    return;
+  }
+
+  if (const Operator *I = dyn_cast<Operator>(V))
+    computeKnownBitsFromOperator(I, DemandedElts, Known, Depth, Q);
+
+  // Aligned pointers have trailing zeros - refine Known.Zero set
+  if (isa<PointerType>(V->getType())) {
+    Align Alignment = V->getPointerAlignment(Q.DL);
+    Known.Zero.setLowBits(Log2(Alignment));
+  }
+
+  // computeKnownBitsFromAssume strictly refines Known.
+  // Therefore, we run them after computeKnownBitsFromOperator.
+
+  // Check whether a nearby assume intrinsic can determine some known bits.
+  computeKnownBitsFromAssume(V, Known, Depth, Q);
+
+  assert((Known.Zero & Known.One) == 0 && "Bits known to be one AND zero?");
+}
+
+/// Try to detect a recurrence that the value of the induction variable is
+/// always a power of two (or zero).
+static bool isPowerOfTwoRecurrence(const PHINode *PN, bool OrZero,
+                                   unsigned Depth, Query &Q) {
+  BinaryOperator *BO = nullptr;
+  Value *Start = nullptr, *Step = nullptr;
+  if (!matchSimpleRecurrence(PN, BO, Start, Step))
+    return false;
+
+  // Initial value must be a power of two.
+  for (const Use &U : PN->operands()) {
+    if (U.get() == Start) {
+      // Initial value comes from a different BB, need to adjust context
+      // instruction for analysis.
+      Q.CxtI = PN->getIncomingBlock(U)->getTerminator();
+      if (!isKnownToBeAPowerOfTwo(Start, OrZero, Depth, Q))
+        return false;
+    }
+  }
+
+  // Except for Mul, the induction variable must be on the left side of the
+  // increment expression, otherwise its value can be arbitrary.
+  if (BO->getOpcode() != Instruction::Mul && BO->getOperand(1) != Step)
+    return false;
+
+  Q.CxtI = BO->getParent()->getTerminator();
+  switch (BO->getOpcode()) {
+  case Instruction::Mul:
+    // Power of two is closed under multiplication.
+    return (OrZero || Q.IIQ.hasNoUnsignedWrap(BO) ||
+            Q.IIQ.hasNoSignedWrap(BO)) &&
+           isKnownToBeAPowerOfTwo(Step, OrZero, Depth, Q);
+  case Instruction::SDiv:
+    // Start value must not be signmask for signed division, so simply being a
+    // power of two is not sufficient, and it has to be a constant.
+    if (!match(Start, m_Power2()) || match(Start, m_SignMask()))
+      return false;
+    [[fallthrough]];
+  case Instruction::UDiv:
+    // Divisor must be a power of two.
+    // If OrZero is false, cannot guarantee induction variable is non-zero after
+    // division, same for Shr, unless it is exact division.
+    return (OrZero || Q.IIQ.isExact(BO)) &&
+           isKnownToBeAPowerOfTwo(Step, false, Depth, Q);
+  case Instruction::Shl:
+    return OrZero || Q.IIQ.hasNoUnsignedWrap(BO) || Q.IIQ.hasNoSignedWrap(BO);
+  case Instruction::AShr:
+    if (!match(Start, m_Power2()) || match(Start, m_SignMask()))
+      return false;
+    [[fallthrough]];
+  case Instruction::LShr:
+    return OrZero || Q.IIQ.isExact(BO);
+  default:
+    return false;
+  }
+}
+
+/// Return true if the given value is known to have exactly one
+/// bit set when defined. For vectors return true if every element is known to
+/// be a power of two when defined. Supports values with integer or pointer
+/// types and vectors of integers.
+bool isKnownToBeAPowerOfTwo(const Value *V, bool OrZero, unsigned Depth,
+                            const Query &Q) {
+  assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
+
+  // Attempt to match against constants.
+  if (OrZero && match(V, m_Power2OrZero()))
+      return true;
+  if (match(V, m_Power2()))
+      return true;
+
+  // 1 << X is clearly a power of two if the one is not shifted off the end.  If
+  // it is shifted off the end then the result is undefined.
+  if (match(V, m_Shl(m_One(), m_Value())))
+    return true;
+
+  // (signmask) >>l X is clearly a power of two if the one is not shifted off
+  // the bottom.  If it is shifted off the bottom then the result is undefined.
+  if (match(V, m_LShr(m_SignMask(), m_Value())))
+    return true;
+
+  // The remaining tests are all recursive, so bail out if we hit the limit.
+  if (Depth++ == MaxAnalysisRecursionDepth)
+    return false;
+
+  Value *X = nullptr, *Y = nullptr;
+  // A shift left or a logical shift right of a power of two is a power of two
+  // or zero.
+  if (OrZero && (match(V, m_Shl(m_Value(X), m_Value())) ||
+                 match(V, m_LShr(m_Value(X), m_Value()))))
+    return isKnownToBeAPowerOfTwo(X, /*OrZero*/ true, Depth, Q);
+
+  if (const ZExtInst *ZI = dyn_cast<ZExtInst>(V))
+    return isKnownToBeAPowerOfTwo(ZI->getOperand(0), OrZero, Depth, Q);
+
+  if (const SelectInst *SI = dyn_cast<SelectInst>(V))
+    return isKnownToBeAPowerOfTwo(SI->getTrueValue(), OrZero, Depth, Q) &&
+           isKnownToBeAPowerOfTwo(SI->getFalseValue(), OrZero, Depth, Q);
+
+  // Peek through min/max.
+  if (match(V, m_MaxOrMin(m_Value(X), m_Value(Y)))) {
+    return isKnownToBeAPowerOfTwo(X, OrZero, Depth, Q) &&
+           isKnownToBeAPowerOfTwo(Y, OrZero, Depth, Q);
+  }
+
+  if (OrZero && match(V, m_And(m_Value(X), m_Value(Y)))) {
+    // A power of two and'd with anything is a power of two or zero.
+    if (isKnownToBeAPowerOfTwo(X, /*OrZero*/ true, Depth, Q) ||
+        isKnownToBeAPowerOfTwo(Y, /*OrZero*/ true, Depth, Q))
+      return true;
+    // X & (-X) is always a power of two or zero.
+    if (match(X, m_Neg(m_Specific(Y))) || match(Y, m_Neg(m_Specific(X))))
+      return true;
+    return false;
+  }
+
+  // Adding a power-of-two or zero to the same power-of-two or zero yields
+  // either the original power-of-two, a larger power-of-two or zero.
+  if (match(V, m_Add(m_Value(X), m_Value(Y)))) {
+    const OverflowingBinaryOperator *VOBO = cast<OverflowingBinaryOperator>(V);
+    if (OrZero || Q.IIQ.hasNoUnsignedWrap(VOBO) ||
+        Q.IIQ.hasNoSignedWrap(VOBO)) {
+      if (match(X, m_And(m_Specific(Y), m_Value())) ||
+          match(X, m_And(m_Value(), m_Specific(Y))))
+        if (isKnownToBeAPowerOfTwo(Y, OrZero, Depth, Q))
+          return true;
+      if (match(Y, m_And(m_Specific(X), m_Value())) ||
+          match(Y, m_And(m_Value(), m_Specific(X))))
+        if (isKnownToBeAPowerOfTwo(X, OrZero, Depth, Q))
+          return true;
+
+      unsigned BitWidth = V->getType()->getScalarSizeInBits();
+      KnownBits LHSBits(BitWidth);
+      computeKnownBits(X, LHSBits, Depth, Q);
+
+      KnownBits RHSBits(BitWidth);
+      computeKnownBits(Y, RHSBits, Depth, Q);
+      // If i8 V is a power of two or zero:
+      //  ZeroBits: 1 1 1 0 1 1 1 1
+      // ~ZeroBits: 0 0 0 1 0 0 0 0
+      if ((~(LHSBits.Zero & RHSBits.Zero)).isPowerOf2())
+        // If OrZero isn't set, we cannot give back a zero result.
+        // Make sure either the LHS or RHS has a bit set.
+        if (OrZero || RHSBits.One.getBoolValue() || LHSBits.One.getBoolValue())
+          return true;
+    }
+  }
+
+  // A PHI node is power of two if all incoming values are power of two, or if
+  // it is an induction variable where in each step its value is a power of two.
+  if (const PHINode *PN = dyn_cast<PHINode>(V)) {
+    Query RecQ = Q;
+
+    // Check if it is an induction variable and always power of two.
+    if (isPowerOfTwoRecurrence(PN, OrZero, Depth, RecQ))
+      return true;
+
+    // Recursively check all incoming values. Limit recursion to 2 levels, so
+    // that search complexity is limited to number of operands^2.
+    unsigned NewDepth = std::max(Depth, MaxAnalysisRecursionDepth - 1);
+    return llvm::all_of(PN->operands(), [&](const Use &U) {
+      // Value is power of 2 if it is coming from PHI node itself by induction.
+      if (U.get() == PN)
+        return true;
+
+      // Change the context instruction to the incoming block where it is
+      // evaluated.
+      RecQ.CxtI = PN->getIncomingBlock(U)->getTerminator();
+      return isKnownToBeAPowerOfTwo(U.get(), OrZero, NewDepth, RecQ);
+    });
+  }
+
+  // An exact divide or right shift can only shift off zero bits, so the result
+  // is a power of two only if the first operand is a power of two and not
+  // copying a sign bit (sdiv int_min, 2).
+  if (match(V, m_Exact(m_LShr(m_Value(), m_Value()))) ||
+      match(V, m_Exact(m_UDiv(m_Value(), m_Value())))) {
+    return isKnownToBeAPowerOfTwo(cast<Operator>(V)->getOperand(0), OrZero,
+                                  Depth, Q);
+  }
+
+  return false;
+}
+
+/// Test whether a GEP's result is known to be non-null.
+///
+/// Uses properties inherent in a GEP to try to determine whether it is known
+/// to be non-null.
+///
+/// Currently this routine does not support vector GEPs.
+static bool isGEPKnownNonNull(const GEPOperator *GEP, unsigned Depth,
+                              const Query &Q) {
+  const Function *F = nullptr;
+  if (const Instruction *I = dyn_cast<Instruction>(GEP))
+    F = I->getFunction();
+
+  if (!GEP->isInBounds() ||
+      NullPointerIsDefined(F, GEP->getPointerAddressSpace()))
+    return false;
+
+  // FIXME: Support vector-GEPs.
+  assert(GEP->getType()->isPointerTy() && "We only support plain pointer GEP");
+
+  // If the base pointer is non-null, we cannot walk to a null address with an
+  // inbounds GEP in address space zero.
+  if (isKnownNonZero(GEP->getPointerOperand(), Depth, Q))
+    return true;
+
+  // Walk the GEP operands and see if any operand introduces a non-zero offset.
+  // If so, then the GEP cannot produce a null pointer, as doing so would
+  // inherently violate the inbounds contract within address space zero.
+  for (gep_type_iterator GTI = gep_type_begin(GEP), GTE = gep_type_end(GEP);
+       GTI != GTE; ++GTI) {
+    // Struct types are easy -- they must always be indexed by a constant.
+    if (StructType *STy = GTI.getStructTypeOrNull()) {
+      ConstantInt *OpC = cast<ConstantInt>(GTI.getOperand());
+      unsigned ElementIdx = OpC->getZExtValue();
+      const StructLayout *SL = Q.DL.getStructLayout(STy);
+      uint64_t ElementOffset = SL->getElementOffset(ElementIdx);
+      if (ElementOffset > 0)
+        return true;
+      continue;
+    }
+
+    // If we have a zero-sized type, the index doesn't matter. Keep looping.
+    if (Q.DL.getTypeAllocSize(GTI.getIndexedType()).isZero())
+      continue;
+
+    // Fast path the constant operand case both for efficiency and so we don't
+    // increment Depth when just zipping down an all-constant GEP.
+    if (ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand())) {
+      if (!OpC->isZero())
+        return true;
+      continue;
+    }
+
+    // We post-increment Depth here because while isKnownNonZero increments it
+    // as well, when we pop back up that increment won't persist. We don't want
+    // to recurse 10k times just because we have 10k GEP operands. We don't
+    // bail completely out because we want to handle constant GEPs regardless
+    // of depth.
+    if (Depth++ >= MaxAnalysisRecursionDepth)
+      continue;
+
+    if (isKnownNonZero(GTI.getOperand(), Depth, Q))
+      return true;
+  }
+
+  return false;
+}
+
+static bool isKnownNonNullFromDominatingCondition(const Value *V,
+                                                  const Instruction *CtxI,
+                                                  const DominatorTree *DT) {
+  if (isa<Constant>(V))
+    return false;
+
+  if (!CtxI || !DT)
+    return false;
+
+  unsigned NumUsesExplored = 0;
+  for (const auto *U : V->users()) {
+    // Avoid massive lists
+    if (NumUsesExplored >= DomConditionsMaxUses)
+      break;
+    NumUsesExplored++;
+
+    // If the value is used as an argument to a call or invoke, then argument
+    // attributes may provide an answer about null-ness.
+    if (const auto *CB = dyn_cast<CallBase>(U))
+      if (auto *CalledFunc = CB->getCalledFunction())
+        for (const Argument &Arg : CalledFunc->args())
+          if (CB->getArgOperand(Arg.getArgNo()) == V &&
+              Arg.hasNonNullAttr(/* AllowUndefOrPoison */ false) &&
+              DT->dominates(CB, CtxI))
+            return true;
+
+    // If the value is used as a load/store, then the pointer must be non null.
+    if (V == getLoadStorePointerOperand(U)) {
+      const Instruction *I = cast<Instruction>(U);
+      if (!NullPointerIsDefined(I->getFunction(),
+                                V->getType()->getPointerAddressSpace()) &&
+          DT->dominates(I, CtxI))
+        return true;
+    }
+
+    // Consider only compare instructions uniquely controlling a branch
+    Value *RHS;
+    CmpInst::Predicate Pred;
+    if (!match(U, m_c_ICmp(Pred, m_Specific(V), m_Value(RHS))))
+      continue;
+
+    bool NonNullIfTrue;
+    if (cmpExcludesZero(Pred, RHS))
+      NonNullIfTrue = true;
+    else if (cmpExcludesZero(CmpInst::getInversePredicate(Pred), RHS))
+      NonNullIfTrue = false;
+    else
+      continue;
+
+    SmallVector<const User *, 4> WorkList;
+    SmallPtrSet<const User *, 4> Visited;
+    for (const auto *CmpU : U->users()) {
+      assert(WorkList.empty() && "Should be!");
+      if (Visited.insert(CmpU).second)
+        WorkList.push_back(CmpU);
+
+      while (!WorkList.empty()) {
+        auto *Curr = WorkList.pop_back_val();
+
+        // If a user is an AND, add all its users to the work list. We only
+        // propagate "pred != null" condition through AND because it is only
+        // correct to assume that all conditions of AND are met in true branch.
+        // TODO: Support similar logic of OR and EQ predicate?
+        if (NonNullIfTrue)
+          if (match(Curr, m_LogicalAnd(m_Value(), m_Value()))) {
+            for (const auto *CurrU : Curr->users())
+              if (Visited.insert(CurrU).second)
+                WorkList.push_back(CurrU);
+            continue;
+          }
+
+        if (const BranchInst *BI = dyn_cast<BranchInst>(Curr)) {
+          assert(BI->isConditional() && "uses a comparison!");
+
+          BasicBlock *NonNullSuccessor =
+              BI->getSuccessor(NonNullIfTrue ? 0 : 1);
+          BasicBlockEdge Edge(BI->getParent(), NonNullSuccessor);
+          if (Edge.isSingleEdge() && DT->dominates(Edge, CtxI->getParent()))
+            return true;
+        } else if (NonNullIfTrue && isGuard(Curr) &&
+                   DT->dominates(cast<Instruction>(Curr), CtxI)) {
+          return true;
+        }
+      }
+    }
+  }
+
+  return false;
+}
+
+/// Does the 'Range' metadata (which must be a valid MD_range operand list)
+/// ensure that the value it's attached to is never Value?  'RangeType' is
+/// is the type of the value described by the range.
+static bool rangeMetadataExcludesValue(const MDNode* Ranges, const APInt& Value) {
+  const unsigned NumRanges = Ranges->getNumOperands() / 2;
+  assert(NumRanges >= 1);
+  for (unsigned i = 0; i < NumRanges; ++i) {
+    ConstantInt *Lower =
+        mdconst::extract<ConstantInt>(Ranges->getOperand(2 * i + 0));
+    ConstantInt *Upper =
+        mdconst::extract<ConstantInt>(Ranges->getOperand(2 * i + 1));
+    ConstantRange Range(Lower->getValue(), Upper->getValue());
+    if (Range.contains(Value))
+      return false;
+  }
+  return true;
+}
+
+/// Try to detect a recurrence that monotonically increases/decreases from a
+/// non-zero starting value. These are common as induction variables.
+static bool isNonZeroRecurrence(const PHINode *PN) {
+  BinaryOperator *BO = nullptr;
+  Value *Start = nullptr, *Step = nullptr;
+  const APInt *StartC, *StepC;
+  if (!matchSimpleRecurrence(PN, BO, Start, Step) ||
+      !match(Start, m_APInt(StartC)) || StartC->isZero())
+    return false;
+
+  switch (BO->getOpcode()) {
+  case Instruction::Add:
+    // Starting from non-zero and stepping away from zero can never wrap back
+    // to zero.
+    return BO->hasNoUnsignedWrap() ||
+           (BO->hasNoSignedWrap() && match(Step, m_APInt(StepC)) &&
+            StartC->isNegative() == StepC->isNegative());
+  case Instruction::Mul:
+    return (BO->hasNoUnsignedWrap() || BO->hasNoSignedWrap()) &&
+           match(Step, m_APInt(StepC)) && !StepC->isZero();
+  case Instruction::Shl:
+    return BO->hasNoUnsignedWrap() || BO->hasNoSignedWrap();
+  case Instruction::AShr:
+  case Instruction::LShr:
+    return BO->isExact();
+  default:
+    return false;
+  }
+}
+
+/// Return true if the given value is known to be non-zero when defined. For
+/// vectors, return true if every demanded element is known to be non-zero when
+/// defined. For pointers, if the context instruction and dominator tree are
+/// specified, perform context-sensitive analysis and return true if the
+/// pointer couldn't possibly be null at the specified instruction.
+/// Supports values with integer or pointer type and vectors of integers.
+bool isKnownNonZero(const Value *V, const APInt &DemandedElts, unsigned Depth,
+                    const Query &Q) {
+
+#ifndef NDEBUG
+  Type *Ty = V->getType();
+  assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
+
+  if (auto *FVTy = dyn_cast<FixedVectorType>(Ty)) {
+    assert(
+        FVTy->getNumElements() == DemandedElts.getBitWidth() &&
+        "DemandedElt width should equal the fixed vector number of elements");
+  } else {
+    assert(DemandedElts == APInt(1, 1) &&
+           "DemandedElt width should be 1 for scalars");
+  }
+#endif
+
+  if (auto *C = dyn_cast<Constant>(V)) {
+    if (C->isNullValue())
+      return false;
+    if (isa<ConstantInt>(C))
+      // Must be non-zero due to null test above.
+      return true;
+
+    // For constant vectors, check that all elements are undefined or known
+    // non-zero to determine that the whole vector is known non-zero.
+    if (auto *VecTy = dyn_cast<FixedVectorType>(C->getType())) {
+      for (unsigned i = 0, e = VecTy->getNumElements(); i != e; ++i) {
+        if (!DemandedElts[i])
+          continue;
+        Constant *Elt = C->getAggregateElement(i);
+        if (!Elt || Elt->isNullValue())
+          return false;
+        if (!isa<UndefValue>(Elt) && !isa<ConstantInt>(Elt))
+          return false;
+      }
+      return true;
+    }
+
+    // A global variable in address space 0 is non null unless extern weak
+    // or an absolute symbol reference. Other address spaces may have null as a
+    // valid address for a global, so we can't assume anything.
+    if (const GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
+      if (!GV->isAbsoluteSymbolRef() && !GV->hasExternalWeakLinkage() &&
+          GV->getType()->getAddressSpace() == 0)
+        return true;
+    }
+
+    // For constant expressions, fall through to the Operator code below.
+    if (!isa<ConstantExpr>(V))
+      return false;
+  }
+
+  if (auto *I = dyn_cast<Instruction>(V)) {
+    if (MDNode *Ranges = Q.IIQ.getMetadata(I, LLVMContext::MD_range)) {
+      // If the possible ranges don't contain zero, then the value is
+      // definitely non-zero.
+      if (auto *Ty = dyn_cast<IntegerType>(V->getType())) {
+        const APInt ZeroValue(Ty->getBitWidth(), 0);
+        if (rangeMetadataExcludesValue(Ranges, ZeroValue))
+          return true;
+      }
+    }
+  }
+
+  if (!isa<Constant>(V) && isKnownNonZeroFromAssume(V, Q))
+    return true;
+
+  // Some of the tests below are recursive, so bail out if we hit the limit.
+  if (Depth++ >= MaxAnalysisRecursionDepth)
+    return false;
+
+  // Check for pointer simplifications.
+
+  if (PointerType *PtrTy = dyn_cast<PointerType>(V->getType())) {
+    // Alloca never returns null, malloc might.
+    if (isa<AllocaInst>(V) && Q.DL.getAllocaAddrSpace() == 0)
+      return true;
+
+    // A byval, inalloca may not be null in a non-default addres space. A
+    // nonnull argument is assumed never 0.
+    if (const Argument *A = dyn_cast<Argument>(V)) {
+      if (((A->hasPassPointeeByValueCopyAttr() &&
+            !NullPointerIsDefined(A->getParent(), PtrTy->getAddressSpace())) ||
+           A->hasNonNullAttr()))
+        return true;
+    }
+
+    // A Load tagged with nonnull metadata is never null.
+    if (const LoadInst *LI = dyn_cast<LoadInst>(V))
+      if (Q.IIQ.getMetadata(LI, LLVMContext::MD_nonnull))
+        return true;
+
+    if (const auto *Call = dyn_cast<CallBase>(V)) {
+      if (Call->isReturnNonNull())
+        return true;
+      if (const auto *RP = getArgumentAliasingToReturnedPointer(Call, true))
+        return isKnownNonZero(RP, Depth, Q);
+    }
+  }
+
+  if (!isa<Constant>(V) &&
+      isKnownNonNullFromDominatingCondition(V, Q.CxtI, Q.DT))
+    return true;
+
+  const Operator *I = dyn_cast<Operator>(V);
+  if (!I)
+    return false;
+
+  unsigned BitWidth = getBitWidth(V->getType()->getScalarType(), Q.DL);
+  switch (I->getOpcode()) {
+  case Instruction::GetElementPtr:
+    if (I->getType()->isPointerTy())
+      return isGEPKnownNonNull(cast<GEPOperator>(I), Depth, Q);
+    break;
+  case Instruction::BitCast:
+    if (I->getType()->isPointerTy())
+      return isKnownNonZero(I->getOperand(0), Depth, Q);
+    break;
+  case Instruction::IntToPtr:
+    // Note that we have to take special care to avoid looking through
+    // truncating casts, e.g., int2ptr/ptr2int with appropriate sizes, as well
+    // as casts that can alter the value, e.g., AddrSpaceCasts.
+    if (!isa<ScalableVectorType>(I->getType()) &&
+        Q.DL.getTypeSizeInBits(I->getOperand(0)->getType()).getFixedValue() <=
+            Q.DL.getTypeSizeInBits(I->getType()).getFixedValue())
+      return isKnownNonZero(I->getOperand(0), Depth, Q);
+    break;
+  case Instruction::PtrToInt:
+    // Similar to int2ptr above, we can look through ptr2int here if the cast
+    // is a no-op or an extend and not a truncate.
+    if (!isa<ScalableVectorType>(I->getType()) &&
+        Q.DL.getTypeSizeInBits(I->getOperand(0)->getType()).getFixedValue() <=
+            Q.DL.getTypeSizeInBits(I->getType()).getFixedValue())
+      return isKnownNonZero(I->getOperand(0), Depth, Q);
+    break;
+  case Instruction::Or:
+    // X | Y != 0 if X != 0 or Y != 0.
+    return isKnownNonZero(I->getOperand(0), DemandedElts, Depth, Q) ||
+           isKnownNonZero(I->getOperand(1), DemandedElts, Depth, Q);
+  case Instruction::SExt:
+  case Instruction::ZExt:
+    // ext X != 0 if X != 0.
+    return isKnownNonZero(I->getOperand(0), Depth, Q);
+
+  case Instruction::Shl: {
+    // shl nuw can't remove any non-zero bits.
+    const OverflowingBinaryOperator *BO = cast<OverflowingBinaryOperator>(V);
+    if (Q.IIQ.hasNoUnsignedWrap(BO))
+      return isKnownNonZero(I->getOperand(0), Depth, Q);
+
+    // shl X, Y != 0 if X is odd.  Note that the value of the shift is undefined
+    // if the lowest bit is shifted off the end.
+    KnownBits Known(BitWidth);
+    computeKnownBits(I->getOperand(0), DemandedElts, Known, Depth, Q);
+    if (Known.One[0])
+      return true;
+    break;
+  }
+  case Instruction::LShr:
+  case Instruction::AShr: {
+    // shr exact can only shift out zero bits.
+    const PossiblyExactOperator *BO = cast<PossiblyExactOperator>(V);
+    if (BO->isExact())
+      return isKnownNonZero(I->getOperand(0), Depth, Q);
+
+    // shr X, Y != 0 if X is negative.  Note that the value of the shift is not
+    // defined if the sign bit is shifted off the end.
+    KnownBits Known =
+        computeKnownBits(I->getOperand(0), DemandedElts, Depth, Q);
+    if (Known.isNegative())
+      return true;
+
+    // If the shifter operand is a constant, and all of the bits shifted
+    // out are known to be zero, and X is known non-zero then at least one
+    // non-zero bit must remain.
+    if (ConstantInt *Shift = dyn_cast<ConstantInt>(I->getOperand(1))) {
+      auto ShiftVal = Shift->getLimitedValue(BitWidth - 1);
+      // Is there a known one in the portion not shifted out?
+      if (Known.countMaxLeadingZeros() < BitWidth - ShiftVal)
+        return true;
+      // Are all the bits to be shifted out known zero?
+      if (Known.countMinTrailingZeros() >= ShiftVal)
+        return isKnownNonZero(I->getOperand(0), DemandedElts, Depth, Q);
+    }
+    break;
+  }
+  case Instruction::UDiv:
+  case Instruction::SDiv:
+    // div exact can only produce a zero if the dividend is zero.
+    if (cast<PossiblyExactOperator>(I)->isExact())
+      return isKnownNonZero(I->getOperand(0), DemandedElts, Depth, Q);
+    break;
+  case Instruction::Add: {
+    // X + Y.
+    KnownBits XKnown =
+        computeKnownBits(I->getOperand(0), DemandedElts, Depth, Q);
+    KnownBits YKnown =
+        computeKnownBits(I->getOperand(1), DemandedElts, Depth, Q);
+
+    // If X and Y are both non-negative (as signed values) then their sum is not
+    // zero unless both X and Y are zero.
+    if (XKnown.isNonNegative() && YKnown.isNonNegative())
+      if (isKnownNonZero(I->getOperand(0), DemandedElts, Depth, Q) ||
+          isKnownNonZero(I->getOperand(1), DemandedElts, Depth, Q))
+        return true;
+
+    // If X and Y are both negative (as signed values) then their sum is not
+    // zero unless both X and Y equal INT_MIN.
+    if (XKnown.isNegative() && YKnown.isNegative()) {
+      APInt Mask = APInt::getSignedMaxValue(BitWidth);
+      // The sign bit of X is set.  If some other bit is set then X is not equal
+      // to INT_MIN.
+      if (XKnown.One.intersects(Mask))
+        return true;
+      // The sign bit of Y is set.  If some other bit is set then Y is not equal
+      // to INT_MIN.
+      if (YKnown.One.intersects(Mask))
+        return true;
+    }
+
+    // The sum of a non-negative number and a power of two is not zero.
+    if (XKnown.isNonNegative() &&
+        isKnownToBeAPowerOfTwo(I->getOperand(1), /*OrZero*/ false, Depth, Q))
+      return true;
+    if (YKnown.isNonNegative() &&
+        isKnownToBeAPowerOfTwo(I->getOperand(0), /*OrZero*/ false, Depth, Q))
+      return true;
+    break;
+  }
+  case Instruction::Mul: {
+    // If X and Y are non-zero then so is X * Y as long as the multiplication
+    // does not overflow.
+    const OverflowingBinaryOperator *BO = cast<OverflowingBinaryOperator>(V);
+    if ((Q.IIQ.hasNoSignedWrap(BO) || Q.IIQ.hasNoUnsignedWrap(BO)) &&
+        isKnownNonZero(I->getOperand(0), DemandedElts, Depth, Q) &&
+        isKnownNonZero(I->getOperand(1), DemandedElts, Depth, Q))
+      return true;
+    break;
+  }
+  case Instruction::Select:
+    // (C ? X : Y) != 0 if X != 0 and Y != 0.
+    if (isKnownNonZero(I->getOperand(1), DemandedElts, Depth, Q) &&
+        isKnownNonZero(I->getOperand(2), DemandedElts, Depth, Q))
+      return true;
+    break;
+  case Instruction::PHI: {
+    auto *PN = cast<PHINode>(I);
+    if (Q.IIQ.UseInstrInfo && isNonZeroRecurrence(PN))
+      return true;
+
+    // Check if all incoming values are non-zero using recursion.
+    Query RecQ = Q;
+    unsigned NewDepth = std::max(Depth, MaxAnalysisRecursionDepth - 1);
+    return llvm::all_of(PN->operands(), [&](const Use &U) {
+      if (U.get() == PN)
+        return true;
+      RecQ.CxtI = PN->getIncomingBlock(U)->getTerminator();
+      return isKnownNonZero(U.get(), DemandedElts, NewDepth, RecQ);
+    });
+  }
+  case Instruction::ExtractElement:
+    if (const auto *EEI = dyn_cast<ExtractElementInst>(V)) {
+      const Value *Vec = EEI->getVectorOperand();
+      const Value *Idx = EEI->getIndexOperand();
+      auto *CIdx = dyn_cast<ConstantInt>(Idx);
+      if (auto *VecTy = dyn_cast<FixedVectorType>(Vec->getType())) {
+        unsigned NumElts = VecTy->getNumElements();
+        APInt DemandedVecElts = APInt::getAllOnes(NumElts);
+        if (CIdx && CIdx->getValue().ult(NumElts))
+          DemandedVecElts = APInt::getOneBitSet(NumElts, CIdx->getZExtValue());
+        return isKnownNonZero(Vec, DemandedVecElts, Depth, Q);
+      }
+    }
+    break;
+  case Instruction::Freeze:
+    return isKnownNonZero(I->getOperand(0), Depth, Q) &&
+           isGuaranteedNotToBePoison(I->getOperand(0), Q.AC, Q.CxtI, Q.DT,
+                                     Depth);
+  case Instruction::Call:
+    if (cast<CallInst>(I)->getIntrinsicID() == Intrinsic::vscale)
+      return true;
+    break;
+  }
+
+  KnownBits Known(BitWidth);
+  computeKnownBits(V, DemandedElts, Known, Depth, Q);
+  return Known.One != 0;
+}
+
+bool isKnownNonZero(const Value* V, unsigned Depth, const Query& Q) {
+  auto *FVTy = dyn_cast<FixedVectorType>(V->getType());
+  APInt DemandedElts =
+      FVTy ? APInt::getAllOnes(FVTy->getNumElements()) : APInt(1, 1);
+  return isKnownNonZero(V, DemandedElts, Depth, Q);
+}
+
+/// If the pair of operators are the same invertible function, return the
+/// the operands of the function corresponding to each input. Otherwise,
+/// return std::nullopt.  An invertible function is one that is 1-to-1 and maps
+/// every input value to exactly one output value.  This is equivalent to
+/// saying that Op1 and Op2 are equal exactly when the specified pair of
+/// operands are equal, (except that Op1 and Op2 may be poison more often.)
+static std::optional<std::pair<Value*, Value*>>
+getInvertibleOperands(const Operator *Op1,
+                      const Operator *Op2) {
+  if (Op1->getOpcode() != Op2->getOpcode())
+    return std::nullopt;
+
+  auto getOperands = [&](unsigned OpNum) -> auto {
+    return std::make_pair(Op1->getOperand(OpNum), Op2->getOperand(OpNum));
+  };
+
+  switch (Op1->getOpcode()) {
+  default:
+    break;
+  case Instruction::Add:
+  case Instruction::Sub:
+    if (Op1->getOperand(0) == Op2->getOperand(0))
+      return getOperands(1);
+    if (Op1->getOperand(1) == Op2->getOperand(1))
+      return getOperands(0);
+    break;
+  case Instruction::Mul: {
+    // invertible if A * B == (A * B) mod 2^N where A, and B are integers
+    // and N is the bitwdith.  The nsw case is non-obvious, but proven by
+    // alive2: https://alive2.llvm.org/ce/z/Z6D5qK
+    auto *OBO1 = cast<OverflowingBinaryOperator>(Op1);
+    auto *OBO2 = cast<OverflowingBinaryOperator>(Op2);
+    if ((!OBO1->hasNoUnsignedWrap() || !OBO2->hasNoUnsignedWrap()) &&
+        (!OBO1->hasNoSignedWrap() || !OBO2->hasNoSignedWrap()))
+      break;
+
+    // Assume operand order has been canonicalized
+    if (Op1->getOperand(1) == Op2->getOperand(1) &&
+        isa<ConstantInt>(Op1->getOperand(1)) &&
+        !cast<ConstantInt>(Op1->getOperand(1))->isZero())
+      return getOperands(0);
+    break;
+  }
+  case Instruction::Shl: {
+    // Same as multiplies, with the difference that we don't need to check
+    // for a non-zero multiply. Shifts always multiply by non-zero.
+    auto *OBO1 = cast<OverflowingBinaryOperator>(Op1);
+    auto *OBO2 = cast<OverflowingBinaryOperator>(Op2);
+    if ((!OBO1->hasNoUnsignedWrap() || !OBO2->hasNoUnsignedWrap()) &&
+        (!OBO1->hasNoSignedWrap() || !OBO2->hasNoSignedWrap()))
+      break;
+
+    if (Op1->getOperand(1) == Op2->getOperand(1))
+      return getOperands(0);
+    break;
+  }
+  case Instruction::AShr:
+  case Instruction::LShr: {
+    auto *PEO1 = cast<PossiblyExactOperator>(Op1);
+    auto *PEO2 = cast<PossiblyExactOperator>(Op2);
+    if (!PEO1->isExact() || !PEO2->isExact())
+      break;
+
+    if (Op1->getOperand(1) == Op2->getOperand(1))
+      return getOperands(0);
+    break;
+  }
+  case Instruction::SExt:
+  case Instruction::ZExt:
+    if (Op1->getOperand(0)->getType() == Op2->getOperand(0)->getType())
+      return getOperands(0);
+    break;
+  case Instruction::PHI: {
+    const PHINode *PN1 = cast<PHINode>(Op1);
+    const PHINode *PN2 = cast<PHINode>(Op2);
+
+    // If PN1 and PN2 are both recurrences, can we prove the entire recurrences
+    // are a single invertible function of the start values? Note that repeated
+    // application of an invertible function is also invertible
+    BinaryOperator *BO1 = nullptr;
+    Value *Start1 = nullptr, *Step1 = nullptr;
+    BinaryOperator *BO2 = nullptr;
+    Value *Start2 = nullptr, *Step2 = nullptr;
+    if (PN1->getParent() != PN2->getParent() ||
+        !matchSimpleRecurrence(PN1, BO1, Start1, Step1) ||
+        !matchSimpleRecurrence(PN2, BO2, Start2, Step2))
+      break;
+
+    auto Values = getInvertibleOperands(cast<Operator>(BO1),
+                                        cast<Operator>(BO2));
+    if (!Values)
+       break;
+
+    // We have to be careful of mutually defined recurrences here.  Ex:
+    // * X_i = X_(i-1) OP Y_(i-1), and Y_i = X_(i-1) OP V
+    // * X_i = Y_i = X_(i-1) OP Y_(i-1)
+    // The invertibility of these is complicated, and not worth reasoning
+    // about (yet?).
+    if (Values->first != PN1 || Values->second != PN2)
+      break;
+
+    return std::make_pair(Start1, Start2);
+  }
+  }
+  return std::nullopt;
+}
+
+/// Return true if V2 == V1 + X, where X is known non-zero.
+static bool isAddOfNonZero(const Value *V1, const Value *V2, unsigned Depth,
+                           const Query &Q) {
+  const BinaryOperator *BO = dyn_cast<BinaryOperator>(V1);
+  if (!BO || BO->getOpcode() != Instruction::Add)
+    return false;
+  Value *Op = nullptr;
+  if (V2 == BO->getOperand(0))
+    Op = BO->getOperand(1);
+  else if (V2 == BO->getOperand(1))
+    Op = BO->getOperand(0);
+  else
+    return false;
+  return isKnownNonZero(Op, Depth + 1, Q);
+}
+
+/// Return true if V2 == V1 * C, where V1 is known non-zero, C is not 0/1 and
+/// the multiplication is nuw or nsw.
+static bool isNonEqualMul(const Value *V1, const Value *V2, unsigned Depth,
+                          const Query &Q) {
+  if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(V2)) {
+    const APInt *C;
+    return match(OBO, m_Mul(m_Specific(V1), m_APInt(C))) &&
+           (OBO->hasNoUnsignedWrap() || OBO->hasNoSignedWrap()) &&
+           !C->isZero() && !C->isOne() && isKnownNonZero(V1, Depth + 1, Q);
+  }
+  return false;
+}
+
+/// Return true if V2 == V1 << C, where V1 is known non-zero, C is not 0 and
+/// the shift is nuw or nsw.
+static bool isNonEqualShl(const Value *V1, const Value *V2, unsigned Depth,
+                          const Query &Q) {
+  if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(V2)) {
+    const APInt *C;
+    return match(OBO, m_Shl(m_Specific(V1), m_APInt(C))) &&
+           (OBO->hasNoUnsignedWrap() || OBO->hasNoSignedWrap()) &&
+           !C->isZero() && isKnownNonZero(V1, Depth + 1, Q);
+  }
+  return false;
+}
+
+static bool isNonEqualPHIs(const PHINode *PN1, const PHINode *PN2,
+                           unsigned Depth, const Query &Q) {
+  // Check two PHIs are in same block.
+  if (PN1->getParent() != PN2->getParent())
+    return false;
+
+  SmallPtrSet<const BasicBlock *, 8> VisitedBBs;
+  bool UsedFullRecursion = false;
+  for (const BasicBlock *IncomBB : PN1->blocks()) {
+    if (!VisitedBBs.insert(IncomBB).second)
+      continue; // Don't reprocess blocks that we have dealt with already.
+    const Value *IV1 = PN1->getIncomingValueForBlock(IncomBB);
+    const Value *IV2 = PN2->getIncomingValueForBlock(IncomBB);
+    const APInt *C1, *C2;
+    if (match(IV1, m_APInt(C1)) && match(IV2, m_APInt(C2)) && *C1 != *C2)
+      continue;
+
+    // Only one pair of phi operands is allowed for full recursion.
+    if (UsedFullRecursion)
+      return false;
+
+    Query RecQ = Q;
+    RecQ.CxtI = IncomBB->getTerminator();
+    if (!isKnownNonEqual(IV1, IV2, Depth + 1, RecQ))
+      return false;
+    UsedFullRecursion = true;
+  }
+  return true;
+}
+
+/// Return true if it is known that V1 != V2.
+static bool isKnownNonEqual(const Value *V1, const Value *V2, unsigned Depth,
+                            const Query &Q) {
+  if (V1 == V2)
+    return false;
+  if (V1->getType() != V2->getType())
+    // We can't look through casts yet.
+    return false;
+
+  if (Depth >= MaxAnalysisRecursionDepth)
+    return false;
+
+  // See if we can recurse through (exactly one of) our operands.  This
+  // requires our operation be 1-to-1 and map every input value to exactly
+  // one output value.  Such an operation is invertible.
+  auto *O1 = dyn_cast<Operator>(V1);
+  auto *O2 = dyn_cast<Operator>(V2);
+  if (O1 && O2 && O1->getOpcode() == O2->getOpcode()) {
+    if (auto Values = getInvertibleOperands(O1, O2))
+      return isKnownNonEqual(Values->first, Values->second, Depth + 1, Q);
+
+    if (const PHINode *PN1 = dyn_cast<PHINode>(V1)) {
+      const PHINode *PN2 = cast<PHINode>(V2);
+      // FIXME: This is missing a generalization to handle the case where one is
+      // a PHI and another one isn't.
+      if (isNonEqualPHIs(PN1, PN2, Depth, Q))
+        return true;
+    };
+  }
+
+  if (isAddOfNonZero(V1, V2, Depth, Q) || isAddOfNonZero(V2, V1, Depth, Q))
+    return true;
+
+  if (isNonEqualMul(V1, V2, Depth, Q) || isNonEqualMul(V2, V1, Depth, Q))
+    return true;
+
+  if (isNonEqualShl(V1, V2, Depth, Q) || isNonEqualShl(V2, V1, Depth, Q))
+    return true;
+
+  if (V1->getType()->isIntOrIntVectorTy()) {
+    // Are any known bits in V1 contradictory to known bits in V2? If V1
+    // has a known zero where V2 has a known one, they must not be equal.
+    KnownBits Known1 = computeKnownBits(V1, Depth, Q);
+    KnownBits Known2 = computeKnownBits(V2, Depth, Q);
+
+    if (Known1.Zero.intersects(Known2.One) ||
+        Known2.Zero.intersects(Known1.One))
+      return true;
+  }
+  return false;
+}
+
+/// Return true if 'V & Mask' is known to be zero.  We use this predicate to
+/// simplify operations downstream. Mask is known to be zero for bits that V
+/// cannot have.
+///
+/// This function is defined on values with integer type, values with pointer
+/// type, and vectors of integers.  In the case
+/// where V is a vector, the mask, known zero, and known one values are the
+/// same width as the vector element, and the bit is set only if it is true
+/// for all of the elements in the vector.
+bool MaskedValueIsZero(const Value *V, const APInt &Mask, unsigned Depth,
+                       const Query &Q) {
+  KnownBits Known(Mask.getBitWidth());
+  computeKnownBits(V, Known, Depth, Q);
+  return Mask.isSubsetOf(Known.Zero);
+}
+
+// Match a signed min+max clamp pattern like smax(smin(In, CHigh), CLow).
+// Returns the input and lower/upper bounds.
+static bool isSignedMinMaxClamp(const Value *Select, const Value *&In,
+                                const APInt *&CLow, const APInt *&CHigh) {
+  assert(isa<Operator>(Select) &&
+         cast<Operator>(Select)->getOpcode() == Instruction::Select &&
+         "Input should be a Select!");
+
+  const Value *LHS = nullptr, *RHS = nullptr;
+  SelectPatternFlavor SPF = matchSelectPattern(Select, LHS, RHS).Flavor;
+  if (SPF != SPF_SMAX && SPF != SPF_SMIN)
+    return false;
+
+  if (!match(RHS, m_APInt(CLow)))
+    return false;
+
+  const Value *LHS2 = nullptr, *RHS2 = nullptr;
+  SelectPatternFlavor SPF2 = matchSelectPattern(LHS, LHS2, RHS2).Flavor;
+  if (getInverseMinMaxFlavor(SPF) != SPF2)
+    return false;
+
+  if (!match(RHS2, m_APInt(CHigh)))
+    return false;
+
+  if (SPF == SPF_SMIN)
+    std::swap(CLow, CHigh);
+
+  In = LHS2;
+  return CLow->sle(*CHigh);
+}
+
+static bool isSignedMinMaxIntrinsicClamp(const IntrinsicInst *II,
+                                         const APInt *&CLow,
+                                         const APInt *&CHigh) {
+  assert((II->getIntrinsicID() == Intrinsic::smin ||
+          II->getIntrinsicID() == Intrinsic::smax) && "Must be smin/smax");
+
+  Intrinsic::ID InverseID = getInverseMinMaxIntrinsic(II->getIntrinsicID());
+  auto *InnerII = dyn_cast<IntrinsicInst>(II->getArgOperand(0));
+  if (!InnerII || InnerII->getIntrinsicID() != InverseID ||
+      !match(II->getArgOperand(1), m_APInt(CLow)) ||
+      !match(InnerII->getArgOperand(1), m_APInt(CHigh)))
+    return false;
+
+  if (II->getIntrinsicID() == Intrinsic::smin)
+    std::swap(CLow, CHigh);
+  return CLow->sle(*CHigh);
+}
+
+/// For vector constants, loop over the elements and find the constant with the
+/// minimum number of sign bits. Return 0 if the value is not a vector constant
+/// or if any element was not analyzed; otherwise, return the count for the
+/// element with the minimum number of sign bits.
+static unsigned computeNumSignBitsVectorConstant(const Value *V,
+                                                 const APInt &DemandedElts,
+                                                 unsigned TyBits) {
+  const auto *CV = dyn_cast<Constant>(V);
+  if (!CV || !isa<FixedVectorType>(CV->getType()))
+    return 0;
+
+  unsigned MinSignBits = TyBits;
+  unsigned NumElts = cast<FixedVectorType>(CV->getType())->getNumElements();
+  for (unsigned i = 0; i != NumElts; ++i) {
+    if (!DemandedElts[i])
+      continue;
+    // If we find a non-ConstantInt, bail out.
+    auto *Elt = dyn_cast_or_null<ConstantInt>(CV->getAggregateElement(i));
+    if (!Elt)
+      return 0;
+
+    MinSignBits = std::min(MinSignBits, Elt->getValue().getNumSignBits());
+  }
+
+  return MinSignBits;
+}
+
+static unsigned ComputeNumSignBitsImpl(const Value *V,
+                                       const APInt &DemandedElts,
+                                       unsigned Depth, const Query &Q);
+
+static unsigned ComputeNumSignBits(const Value *V, const APInt &DemandedElts,
+                                   unsigned Depth, const Query &Q) {
+  unsigned Result = ComputeNumSignBitsImpl(V, DemandedElts, Depth, Q);
+  assert(Result > 0 && "At least one sign bit needs to be present!");
+  return Result;
+}
+
+/// Return the number of times the sign bit of the register is replicated into
+/// the other bits. We know that at least 1 bit is always equal to the sign bit
+/// (itself), but other cases can give us information. For example, immediately
+/// after an "ashr X, 2", we know that the top 3 bits are all equal to each
+/// other, so we return 3. For vectors, return the number of sign bits for the
+/// vector element with the minimum number of known sign bits of the demanded
+/// elements in the vector specified by DemandedElts.
+static unsigned ComputeNumSignBitsImpl(const Value *V,
+                                       const APInt &DemandedElts,
+                                       unsigned Depth, const Query &Q) {
+  Type *Ty = V->getType();
+#ifndef NDEBUG
+  assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
+
+  if (auto *FVTy = dyn_cast<FixedVectorType>(Ty)) {
+    assert(
+        FVTy->getNumElements() == DemandedElts.getBitWidth() &&
+        "DemandedElt width should equal the fixed vector number of elements");
+  } else {
+    assert(DemandedElts == APInt(1, 1) &&
+           "DemandedElt width should be 1 for scalars");
+  }
+#endif
+
+  // We return the minimum number of sign bits that are guaranteed to be present
+  // in V, so for undef we have to conservatively return 1.  We don't have the
+  // same behavior for poison though -- that's a FIXME today.
+
+  Type *ScalarTy = Ty->getScalarType();
+  unsigned TyBits = ScalarTy->isPointerTy() ?
+    Q.DL.getPointerTypeSizeInBits(ScalarTy) :
+    Q.DL.getTypeSizeInBits(ScalarTy);
+
+  unsigned Tmp, Tmp2;
+  unsigned FirstAnswer = 1;
+
+  // Note that ConstantInt is handled by the general computeKnownBits case
+  // below.
+
+  if (Depth == MaxAnalysisRecursionDepth)
+    return 1;
+
+  if (auto *U = dyn_cast<Operator>(V)) {
+    switch (Operator::getOpcode(V)) {
+    default: break;
+    case Instruction::SExt:
+      Tmp = TyBits - U->getOperand(0)->getType()->getScalarSizeInBits();
+      return ComputeNumSignBits(U->getOperand(0), Depth + 1, Q) + Tmp;
+
+    case Instruction::SDiv: {
+      const APInt *Denominator;
+      // sdiv X, C -> adds log(C) sign bits.
+      if (match(U->getOperand(1), m_APInt(Denominator))) {
+
+        // Ignore non-positive denominator.
+        if (!Denominator->isStrictlyPositive())
+          break;
+
+        // Calculate the incoming numerator bits.
+        unsigned NumBits = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+
+        // Add floor(log(C)) bits to the numerator bits.
+        return std::min(TyBits, NumBits + Denominator->logBase2());
+      }
+      break;
+    }
+
+    case Instruction::SRem: {
+      Tmp = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+
+      const APInt *Denominator;
+      // srem X, C -> we know that the result is within [-C+1,C) when C is a
+      // positive constant.  This let us put a lower bound on the number of sign
+      // bits.
+      if (match(U->getOperand(1), m_APInt(Denominator))) {
+
+        // Ignore non-positive denominator.
+        if (Denominator->isStrictlyPositive()) {
+          // Calculate the leading sign bit constraints by examining the
+          // denominator.  Given that the denominator is positive, there are two
+          // cases:
+          //
+          //  1. The numerator is positive. The result range is [0,C) and
+          //     [0,C) u< (1 << ceilLogBase2(C)).
+          //
+          //  2. The numerator is negative. Then the result range is (-C,0] and
+          //     integers in (-C,0] are either 0 or >u (-1 << ceilLogBase2(C)).
+          //
+          // Thus a lower bound on the number of sign bits is `TyBits -
+          // ceilLogBase2(C)`.
+
+          unsigned ResBits = TyBits - Denominator->ceilLogBase2();
+          Tmp = std::max(Tmp, ResBits);
+        }
+      }
+      return Tmp;
+    }
+
+    case Instruction::AShr: {
+      Tmp = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+      // ashr X, C   -> adds C sign bits.  Vectors too.
+      const APInt *ShAmt;
+      if (match(U->getOperand(1), m_APInt(ShAmt))) {
+        if (ShAmt->uge(TyBits))
+          break; // Bad shift.
+        unsigned ShAmtLimited = ShAmt->getZExtValue();
+        Tmp += ShAmtLimited;
+        if (Tmp > TyBits) Tmp = TyBits;
+      }
+      return Tmp;
+    }
+    case Instruction::Shl: {
+      const APInt *ShAmt;
+      if (match(U->getOperand(1), m_APInt(ShAmt))) {
+        // shl destroys sign bits.
+        Tmp = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+        if (ShAmt->uge(TyBits) ||   // Bad shift.
+            ShAmt->uge(Tmp)) break; // Shifted all sign bits out.
+        Tmp2 = ShAmt->getZExtValue();
+        return Tmp - Tmp2;
+      }
+      break;
+    }
+    case Instruction::And:
+    case Instruction::Or:
+    case Instruction::Xor: // NOT is handled here.
+      // Logical binary ops preserve the number of sign bits at the worst.
+      Tmp = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+      if (Tmp != 1) {
+        Tmp2 = ComputeNumSignBits(U->getOperand(1), Depth + 1, Q);
+        FirstAnswer = std::min(Tmp, Tmp2);
+        // We computed what we know about the sign bits as our first
+        // answer. Now proceed to the generic code that uses
+        // computeKnownBits, and pick whichever answer is better.
+      }
+      break;
+
+    case Instruction::Select: {
+      // If we have a clamp pattern, we know that the number of sign bits will
+      // be the minimum of the clamp min/max range.
+      const Value *X;
+      const APInt *CLow, *CHigh;
+      if (isSignedMinMaxClamp(U, X, CLow, CHigh))
+        return std::min(CLow->getNumSignBits(), CHigh->getNumSignBits());
+
+      Tmp = ComputeNumSignBits(U->getOperand(1), Depth + 1, Q);
+      if (Tmp == 1) break;
+      Tmp2 = ComputeNumSignBits(U->getOperand(2), Depth + 1, Q);
+      return std::min(Tmp, Tmp2);
+    }
+
+    case Instruction::Add:
+      // Add can have at most one carry bit.  Thus we know that the output
+      // is, at worst, one more bit than the inputs.
+      Tmp = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+      if (Tmp == 1) break;
+
+      // Special case decrementing a value (ADD X, -1):
+      if (const auto *CRHS = dyn_cast<Constant>(U->getOperand(1)))
+        if (CRHS->isAllOnesValue()) {
+          KnownBits Known(TyBits);
+          computeKnownBits(U->getOperand(0), Known, Depth + 1, Q);
+
+          // If the input is known to be 0 or 1, the output is 0/-1, which is
+          // all sign bits set.
+          if ((Known.Zero | 1).isAllOnes())
+            return TyBits;
+
+          // If we are subtracting one from a positive number, there is no carry
+          // out of the result.
+          if (Known.isNonNegative())
+            return Tmp;
+        }
+
+      Tmp2 = ComputeNumSignBits(U->getOperand(1), Depth + 1, Q);
+      if (Tmp2 == 1) break;
+      return std::min(Tmp, Tmp2) - 1;
+
+    case Instruction::Sub:
+      Tmp2 = ComputeNumSignBits(U->getOperand(1), Depth + 1, Q);
+      if (Tmp2 == 1) break;
+
+      // Handle NEG.
+      if (const auto *CLHS = dyn_cast<Constant>(U->getOperand(0)))
+        if (CLHS->isNullValue()) {
+          KnownBits Known(TyBits);
+          computeKnownBits(U->getOperand(1), Known, Depth + 1, Q);
+          // If the input is known to be 0 or 1, the output is 0/-1, which is
+          // all sign bits set.
+          if ((Known.Zero | 1).isAllOnes())
+            return TyBits;
+
+          // If the input is known to be positive (the sign bit is known clear),
+          // the output of the NEG has the same number of sign bits as the
+          // input.
+          if (Known.isNonNegative())
+            return Tmp2;
+
+          // Otherwise, we treat this like a SUB.
+        }
+
+      // Sub can have at most one carry bit.  Thus we know that the output
+      // is, at worst, one more bit than the inputs.
+      Tmp = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+      if (Tmp == 1) break;
+      return std::min(Tmp, Tmp2) - 1;
+
+    case Instruction::Mul: {
+      // The output of the Mul can be at most twice the valid bits in the
+      // inputs.
+      unsigned SignBitsOp0 = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+      if (SignBitsOp0 == 1) break;
+      unsigned SignBitsOp1 = ComputeNumSignBits(U->getOperand(1), Depth + 1, Q);
+      if (SignBitsOp1 == 1) break;
+      unsigned OutValidBits =
+          (TyBits - SignBitsOp0 + 1) + (TyBits - SignBitsOp1 + 1);
+      return OutValidBits > TyBits ? 1 : TyBits - OutValidBits + 1;
+    }
+
+    case Instruction::PHI: {
+      const PHINode *PN = cast<PHINode>(U);
+      unsigned NumIncomingValues = PN->getNumIncomingValues();
+      // Don't analyze large in-degree PHIs.
+      if (NumIncomingValues > 4) break;
+      // Unreachable blocks may have zero-operand PHI nodes.
+      if (NumIncomingValues == 0) break;
+
+      // Take the minimum of all incoming values.  This can't infinitely loop
+      // because of our depth threshold.
+      Query RecQ = Q;
+      Tmp = TyBits;
+      for (unsigned i = 0, e = NumIncomingValues; i != e; ++i) {
+        if (Tmp == 1) return Tmp;
+        RecQ.CxtI = PN->getIncomingBlock(i)->getTerminator();
+        Tmp = std::min(
+            Tmp, ComputeNumSignBits(PN->getIncomingValue(i), Depth + 1, RecQ));
+      }
+      return Tmp;
+    }
+
+    case Instruction::Trunc: {
+      // If the input contained enough sign bits that some remain after the
+      // truncation, then we can make use of that. Otherwise we don't know
+      // anything.
+      Tmp = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+      unsigned OperandTyBits = U->getOperand(0)->getType()->getScalarSizeInBits();
+      if (Tmp > (OperandTyBits - TyBits))
+        return Tmp - (OperandTyBits - TyBits);
+
+      return 1;
+    }
+
+    case Instruction::ExtractElement:
+      // Look through extract element. At the moment we keep this simple and
+      // skip tracking the specific element. But at least we might find
+      // information valid for all elements of the vector (for example if vector
+      // is sign extended, shifted, etc).
+      return ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+
+    case Instruction::ShuffleVector: {
+      // Collect the minimum number of sign bits that are shared by every vector
+      // element referenced by the shuffle.
+      auto *Shuf = dyn_cast<ShuffleVectorInst>(U);
+      if (!Shuf) {
+        // FIXME: Add support for shufflevector constant expressions.
+        return 1;
+      }
+      APInt DemandedLHS, DemandedRHS;
+      // For undef elements, we don't know anything about the common state of
+      // the shuffle result.
+      if (!getShuffleDemandedElts(Shuf, DemandedElts, DemandedLHS, DemandedRHS))
+        return 1;
+      Tmp = std::numeric_limits<unsigned>::max();
+      if (!!DemandedLHS) {
+        const Value *LHS = Shuf->getOperand(0);
+        Tmp = ComputeNumSignBits(LHS, DemandedLHS, Depth + 1, Q);
+      }
+      // If we don't know anything, early out and try computeKnownBits
+      // fall-back.
+      if (Tmp == 1)
+        break;
+      if (!!DemandedRHS) {
+        const Value *RHS = Shuf->getOperand(1);
+        Tmp2 = ComputeNumSignBits(RHS, DemandedRHS, Depth + 1, Q);
+        Tmp = std::min(Tmp, Tmp2);
+      }
+      // If we don't know anything, early out and try computeKnownBits
+      // fall-back.
+      if (Tmp == 1)
+        break;
+      assert(Tmp <= TyBits && "Failed to determine minimum sign bits");
+      return Tmp;
+    }
+    case Instruction::Call: {
+      if (const auto *II = dyn_cast<IntrinsicInst>(U)) {
+        switch (II->getIntrinsicID()) {
+        default: break;
+        case Intrinsic::abs:
+          Tmp = ComputeNumSignBits(U->getOperand(0), Depth + 1, Q);
+          if (Tmp == 1) break;
+
+          // Absolute value reduces number of sign bits by at most 1.
+          return Tmp - 1;
+        case Intrinsic::smin:
+        case Intrinsic::smax: {
+          const APInt *CLow, *CHigh;
+          if (isSignedMinMaxIntrinsicClamp(II, CLow, CHigh))
+            return std::min(CLow->getNumSignBits(), CHigh->getNumSignBits());
+        }
+        }
+      }
+    }
+    }
+  }
+
+  // Finally, if we can prove that the top bits of the result are 0's or 1's,
+  // use this information.
+
+  // If we can examine all elements of a vector constant successfully, we're
+  // done (we can't do any better than that). If not, keep trying.
+  if (unsigned VecSignBits =
+          computeNumSignBitsVectorConstant(V, DemandedElts, TyBits))
+    return VecSignBits;
+
+  KnownBits Known(TyBits);
+  computeKnownBits(V, DemandedElts, Known, Depth, Q);
+
+  // If we know that the sign bit is either zero or one, determine the number of
+  // identical bits in the top of the input value.
+  return std::max(FirstAnswer, Known.countMinSignBits());
+}
+
+Intrinsic::ID llvm::getIntrinsicForCallSite(const CallBase &CB,
+                                            const TargetLibraryInfo *TLI) {
+  const Function *F = CB.getCalledFunction();
+  if (!F)
+    return Intrinsic::not_intrinsic;
+
+  if (F->isIntrinsic())
+    return F->getIntrinsicID();
+
+  // We are going to infer semantics of a library function based on mapping it
+  // to an LLVM intrinsic. Check that the library function is available from
+  // this callbase and in this environment.
+  LibFunc Func;
+  if (F->hasLocalLinkage() || !TLI || !TLI->getLibFunc(CB, Func) ||
+      !CB.onlyReadsMemory())
+    return Intrinsic::not_intrinsic;
+
+  switch (Func) {
+  default:
+    break;
+  case LibFunc_sin:
+  case LibFunc_sinf:
+  case LibFunc_sinl:
+    return Intrinsic::sin;
+  case LibFunc_cos:
+  case LibFunc_cosf:
+  case LibFunc_cosl:
+    return Intrinsic::cos;
+  case LibFunc_exp:
+  case LibFunc_expf:
+  case LibFunc_expl:
+    return Intrinsic::exp;
+  case LibFunc_exp2:
+  case LibFunc_exp2f:
+  case LibFunc_exp2l:
+    return Intrinsic::exp2;
+  case LibFunc_log:
+  case LibFunc_logf:
+  case LibFunc_logl:
+    return Intrinsic::log;
+  case LibFunc_log10:
+  case LibFunc_log10f:
+  case LibFunc_log10l:
+    return Intrinsic::log10;
+  case LibFunc_log2:
+  case LibFunc_log2f:
+  case LibFunc_log2l:
+    return Intrinsic::log2;
+  case LibFunc_fabs:
+  case LibFunc_fabsf:
+  case LibFunc_fabsl:
+    return Intrinsic::fabs;
+  case LibFunc_fmin:
+  case LibFunc_fminf:
+  case LibFunc_fminl:
+    return Intrinsic::minnum;
+  case LibFunc_fmax:
+  case LibFunc_fmaxf:
+  case LibFunc_fmaxl:
+    return Intrinsic::maxnum;
+  case LibFunc_copysign:
+  case LibFunc_copysignf:
+  case LibFunc_copysignl:
+    return Intrinsic::copysign;
+  case LibFunc_floor:
+  case LibFunc_floorf:
+  case LibFunc_floorl:
+    return Intrinsic::floor;
+  case LibFunc_ceil:
+  case LibFunc_ceilf:
+  case LibFunc_ceill:
+    return Intrinsic::ceil;
+  case LibFunc_trunc:
+  case LibFunc_truncf:
+  case LibFunc_truncl:
+    return Intrinsic::trunc;
+  case LibFunc_rint:
+  case LibFunc_rintf:
+  case LibFunc_rintl:
+    return Intrinsic::rint;
+  case LibFunc_nearbyint:
+  case LibFunc_nearbyintf:
+  case LibFunc_nearbyintl:
+    return Intrinsic::nearbyint;
+  case LibFunc_round:
+  case LibFunc_roundf:
+  case LibFunc_roundl:
+    return Intrinsic::round;
+  case LibFunc_roundeven:
+  case LibFunc_roundevenf:
+  case LibFunc_roundevenl:
+    return Intrinsic::roundeven;
+  case LibFunc_pow:
+  case LibFunc_powf:
+  case LibFunc_powl:
+    return Intrinsic::pow;
+  case LibFunc_sqrt:
+  case LibFunc_sqrtf:
+  case LibFunc_sqrtl:
+    return Intrinsic::sqrt;
+  }
+
+  return Intrinsic::not_intrinsic;
+}
+
+/// Return true if we can prove that the specified FP value is never equal to
+/// -0.0.
+/// NOTE: Do not check 'nsz' here because that fast-math-flag does not guarantee
+///       that a value is not -0.0. It only guarantees that -0.0 may be treated
+///       the same as +0.0 in floating-point ops.
+bool llvm::CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI,
+                                unsigned Depth) {
+  if (auto *CFP = dyn_cast<ConstantFP>(V))
+    return !CFP->getValueAPF().isNegZero();
+
+  if (Depth == MaxAnalysisRecursionDepth)
+    return false;
+
+  auto *Op = dyn_cast<Operator>(V);
+  if (!Op)
+    return false;
+
+  // (fadd x, 0.0) is guaranteed to return +0.0, not -0.0.
+  if (match(Op, m_FAdd(m_Value(), m_PosZeroFP())))
+    return true;
+
+  // sitofp and uitofp turn into +0.0 for zero.
+  if (isa<SIToFPInst>(Op) || isa<UIToFPInst>(Op))
+    return true;
+
+  if (auto *Call = dyn_cast<CallInst>(Op)) {
+    Intrinsic::ID IID = getIntrinsicForCallSite(*Call, TLI);
+    switch (IID) {
+    default:
+      break;
+    // sqrt(-0.0) = -0.0, no other negative results are possible.
+    case Intrinsic::sqrt:
+    case Intrinsic::canonicalize:
+      return CannotBeNegativeZero(Call->getArgOperand(0), TLI, Depth + 1);
+    case Intrinsic::experimental_constrained_sqrt: {
+      // NOTE: This rounding mode restriction may be too strict.
+      const auto *CI = cast<ConstrainedFPIntrinsic>(Call);
+      if (CI->getRoundingMode() == RoundingMode::NearestTiesToEven)
+        return CannotBeNegativeZero(Call->getArgOperand(0), TLI, Depth + 1);
+      else
+        return false;
+    }
+    // fabs(x) != -0.0
+    case Intrinsic::fabs:
+      return true;
+    // sitofp and uitofp turn into +0.0 for zero.
+    case Intrinsic::experimental_constrained_sitofp:
+    case Intrinsic::experimental_constrained_uitofp:
+      return true;
+    }
+  }
+
+  return false;
+}
+
+/// If \p SignBitOnly is true, test for a known 0 sign bit rather than a
+/// standard ordered compare. e.g. make -0.0 olt 0.0 be true because of the sign
+/// bit despite comparing equal.
+static bool cannotBeOrderedLessThanZeroImpl(const Value *V,
+                                            const TargetLibraryInfo *TLI,
+                                            bool SignBitOnly,
+                                            unsigned Depth) {
+  // TODO: This function does not do the right thing when SignBitOnly is true
+  // and we're lowering to a hypothetical IEEE 754-compliant-but-evil platform
+  // which flips the sign bits of NaNs.  See
+  // https://llvm.org/bugs/show_bug.cgi?id=31702.
+
+  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
+    return !CFP->getValueAPF().isNegative() ||
+           (!SignBitOnly && CFP->getValueAPF().isZero());
+  }
+
+  // Handle vector of constants.
+  if (auto *CV = dyn_cast<Constant>(V)) {
+    if (auto *CVFVTy = dyn_cast<FixedVectorType>(CV->getType())) {
+      unsigned NumElts = CVFVTy->getNumElements();
+      for (unsigned i = 0; i != NumElts; ++i) {
+        auto *CFP = dyn_cast_or_null<ConstantFP>(CV->getAggregateElement(i));
+        if (!CFP)
+          return false;
+        if (CFP->getValueAPF().isNegative() &&
+            (SignBitOnly || !CFP->getValueAPF().isZero()))
+          return false;
+      }
+
+      // All non-negative ConstantFPs.
+      return true;
+    }
+  }
+
+  if (Depth == MaxAnalysisRecursionDepth)
+    return false;
+
+  const Operator *I = dyn_cast<Operator>(V);
+  if (!I)
+    return false;
+
+  switch (I->getOpcode()) {
+  default:
+    break;
+  // Unsigned integers are always nonnegative.
+  case Instruction::UIToFP:
+    return true;
+  case Instruction::FDiv:
+    // X / X is always exactly 1.0 or a NaN.
+    if (I->getOperand(0) == I->getOperand(1) &&
+        (!SignBitOnly || cast<FPMathOperator>(I)->hasNoNaNs()))
+      return true;
+
+    // Set SignBitOnly for RHS, because X / -0.0 is -Inf (or NaN).
+    return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly,
+                                           Depth + 1) &&
+           cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI,
+                                           /*SignBitOnly*/ true, Depth + 1);
+  case Instruction::FMul:
+    // X * X is always non-negative or a NaN.
+    if (I->getOperand(0) == I->getOperand(1) &&
+        (!SignBitOnly || cast<FPMathOperator>(I)->hasNoNaNs()))
+      return true;
+
+    [[fallthrough]];
+  case Instruction::FAdd:
+  case Instruction::FRem:
+    return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly,
+                                           Depth + 1) &&
+           cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI, SignBitOnly,
+                                           Depth + 1);
+  case Instruction::Select:
+    return cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI, SignBitOnly,
+                                           Depth + 1) &&
+           cannotBeOrderedLessThanZeroImpl(I->getOperand(2), TLI, SignBitOnly,
+                                           Depth + 1);
+  case Instruction::FPExt:
+  case Instruction::FPTrunc:
+    // Widening/narrowing never change sign.
+    return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly,
+                                           Depth + 1);
+  case Instruction::ExtractElement:
+    // Look through extract element. At the moment we keep this simple and skip
+    // tracking the specific element. But at least we might find information
+    // valid for all elements of the vector.
+    return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly,
+                                           Depth + 1);
+  case Instruction::Call:
+    const auto *CI = cast<CallInst>(I);
+    Intrinsic::ID IID = getIntrinsicForCallSite(*CI, TLI);
+    switch (IID) {
+    default:
+      break;
+    case Intrinsic::canonicalize:
+    case Intrinsic::arithmetic_fence:
+    case Intrinsic::floor:
+    case Intrinsic::ceil:
+    case Intrinsic::trunc:
+    case Intrinsic::rint:
+    case Intrinsic::nearbyint:
+    case Intrinsic::round:
+    case Intrinsic::roundeven:
+    case Intrinsic::fptrunc_round:
+      return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly, Depth + 1);
+    case Intrinsic::maxnum: {
+      Value *V0 = I->getOperand(0), *V1 = I->getOperand(1);
+      auto isPositiveNum = [&](Value *V) {
+        if (SignBitOnly) {
+          // With SignBitOnly, this is tricky because the result of
+          // maxnum(+0.0, -0.0) is unspecified. Just check if the operand is
+          // a constant strictly greater than 0.0.
+          const APFloat *C;
+          return match(V, m_APFloat(C)) &&
+                 *C > APFloat::getZero(C->getSemantics());
+        }
+
+        // -0.0 compares equal to 0.0, so if this operand is at least -0.0,
+        // maxnum can't be ordered-less-than-zero.
+        return isKnownNeverNaN(V, TLI) &&
+               cannotBeOrderedLessThanZeroImpl(V, TLI, false, Depth + 1);
+      };
+
+      // TODO: This could be improved. We could also check that neither operand
+      //       has its sign bit set (and at least 1 is not-NAN?).
+      return isPositiveNum(V0) || isPositiveNum(V1);
+    }
+
+    case Intrinsic::maximum:
+      return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly,
+                                             Depth + 1) ||
+             cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI, SignBitOnly,
+                                             Depth + 1);
+    case Intrinsic::minnum:
+    case Intrinsic::minimum:
+      return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly,
+                                             Depth + 1) &&
+             cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI, SignBitOnly,
+                                             Depth + 1);
+    case Intrinsic::exp:
+    case Intrinsic::exp2:
+    case Intrinsic::fabs:
+      return true;
+    case Intrinsic::copysign:
+      // Only the sign operand matters.
+      return cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI, true,
+                                             Depth + 1);
+    case Intrinsic::sqrt:
+      // sqrt(x) is always >= -0 or NaN.  Moreover, sqrt(x) == -0 iff x == -0.
+      if (!SignBitOnly)
+        return true;
+      return CI->hasNoNaNs() && (CI->hasNoSignedZeros() ||
+                                 CannotBeNegativeZero(CI->getOperand(0), TLI));
+
+    case Intrinsic::powi:
+      if (ConstantInt *Exponent = dyn_cast<ConstantInt>(I->getOperand(1))) {
+        // powi(x,n) is non-negative if n is even.
+        if (Exponent->getBitWidth() <= 64 && Exponent->getSExtValue() % 2u == 0)
+          return true;
+      }
+      // TODO: This is not correct.  Given that exp is an integer, here are the
+      // ways that pow can return a negative value:
+      //
+      //   pow(x, exp)    --> negative if exp is odd and x is negative.
+      //   pow(-0, exp)   --> -inf if exp is negative odd.
+      //   pow(-0, exp)   --> -0 if exp is positive odd.
+      //   pow(-inf, exp) --> -0 if exp is negative odd.
+      //   pow(-inf, exp) --> -inf if exp is positive odd.
+      //
+      // Therefore, if !SignBitOnly, we can return true if x >= +0 or x is NaN,
+      // but we must return false if x == -0.  Unfortunately we do not currently
+      // have a way of expressing this constraint.  See details in
+      // https://llvm.org/bugs/show_bug.cgi?id=31702.
+      return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly,
+                                             Depth + 1);
+
+    case Intrinsic::fma:
+    case Intrinsic::fmuladd:
+      // x*x+y is non-negative if y is non-negative.
+      return I->getOperand(0) == I->getOperand(1) &&
+             (!SignBitOnly || cast<FPMathOperator>(I)->hasNoNaNs()) &&
+             cannotBeOrderedLessThanZeroImpl(I->getOperand(2), TLI, SignBitOnly,
+                                             Depth + 1);
+    }
+    break;
+  }
+  return false;
+}
+
+bool llvm::CannotBeOrderedLessThanZero(const Value *V,
+                                       const TargetLibraryInfo *TLI) {
+  return cannotBeOrderedLessThanZeroImpl(V, TLI, false, 0);
+}
+
+bool llvm::SignBitMustBeZero(const Value *V, const TargetLibraryInfo *TLI) {
+  return cannotBeOrderedLessThanZeroImpl(V, TLI, true, 0);
+}
+
+bool llvm::isKnownNeverInfinity(const Value *V, const TargetLibraryInfo *TLI,
+                                unsigned Depth) {
+  assert(V->getType()->isFPOrFPVectorTy() && "Querying for Inf on non-FP type");
+
+  // If we're told that infinities won't happen, assume they won't.
+  if (auto *FPMathOp = dyn_cast<FPMathOperator>(V))
+    if (FPMathOp->hasNoInfs())
+      return true;
+
+  // Handle scalar constants.
+  if (auto *CFP = dyn_cast<ConstantFP>(V))
+    return !CFP->isInfinity();
+
+  if (Depth == MaxAnalysisRecursionDepth)
+    return false;
+
+  if (auto *Inst = dyn_cast<Instruction>(V)) {
+    switch (Inst->getOpcode()) {
+    case Instruction::Select: {
+      return isKnownNeverInfinity(Inst->getOperand(1), TLI, Depth + 1) &&
+             isKnownNeverInfinity(Inst->getOperand(2), TLI, Depth + 1);
+    }
+    case Instruction::SIToFP:
+    case Instruction::UIToFP: {
+      // Get width of largest magnitude integer (remove a bit if signed).
+      // This still works for a signed minimum value because the largest FP
+      // value is scaled by some fraction close to 2.0 (1.0 + 0.xxxx).
+      int IntSize = Inst->getOperand(0)->getType()->getScalarSizeInBits();
+      if (Inst->getOpcode() == Instruction::SIToFP)
+        --IntSize;
+
+      // If the exponent of the largest finite FP value can hold the largest
+      // integer, the result of the cast must be finite.
+      Type *FPTy = Inst->getType()->getScalarType();
+      return ilogb(APFloat::getLargest(FPTy->getFltSemantics())) >= IntSize;
+    }
+    case Instruction::FNeg:
+    case Instruction::FPExt: {
+      // Peek through to source op. If it is not infinity, this is not infinity.
+      return isKnownNeverInfinity(Inst->getOperand(0), TLI, Depth + 1);
+    }
+    case Instruction::FPTrunc: {
+      // Need a range check.
+      return false;
+    }
+    default:
+      break;
+    }
+
+    if (const auto *II = dyn_cast<IntrinsicInst>(V)) {
+      switch (II->getIntrinsicID()) {
+      case Intrinsic::sin:
+      case Intrinsic::cos:
+        // Return NaN on infinite inputs.
+        return true;
+      case Intrinsic::fabs:
+      case Intrinsic::sqrt:
+      case Intrinsic::canonicalize:
+      case Intrinsic::copysign:
+      case Intrinsic::arithmetic_fence:
+      case Intrinsic::trunc:
+        return isKnownNeverInfinity(Inst->getOperand(0), TLI, Depth + 1);
+      case Intrinsic::floor:
+      case Intrinsic::ceil:
+      case Intrinsic::rint:
+      case Intrinsic::nearbyint:
+      case Intrinsic::round:
+      case Intrinsic::roundeven:
+        // PPC_FP128 is a special case.
+        if (V->getType()->isMultiUnitFPType())
+          return false;
+        return isKnownNeverInfinity(Inst->getOperand(0), TLI, Depth + 1);
+      case Intrinsic::fptrunc_round:
+        // Requires knowing the value range.
+        return false;
+      case Intrinsic::minnum:
+      case Intrinsic::maxnum:
+      case Intrinsic::minimum:
+      case Intrinsic::maximum:
+        return isKnownNeverInfinity(Inst->getOperand(0), TLI, Depth + 1) &&
+               isKnownNeverInfinity(Inst->getOperand(1), TLI, Depth + 1);
+      case Intrinsic::log:
+      case Intrinsic::log10:
+      case Intrinsic::log2:
+        // log(+inf) -> +inf
+        // log([+-]0.0) -> -inf
+        // log(-inf) -> nan
+        // log(-x) -> nan
+        // TODO: We lack API to check the == 0 case.
+        return false;
+      case Intrinsic::exp:
+      case Intrinsic::exp2:
+      case Intrinsic::pow:
+      case Intrinsic::powi:
+      case Intrinsic::fma:
+      case Intrinsic::fmuladd:
+        // These can return infinities on overflow cases, so it's hard to prove
+        // anything about it.
+        return false;
+      default:
+        break;
+      }
+    }
+  }
+
+  // try to handle fixed width vector constants
+  auto *VFVTy = dyn_cast<FixedVectorType>(V->getType());
+  if (VFVTy && isa<Constant>(V)) {
+    // For vectors, verify that each element is not infinity.
+    unsigned NumElts = VFVTy->getNumElements();
+    for (unsigned i = 0; i != NumElts; ++i) {
+      Constant *Elt = cast<Constant>(V)->getAggregateElement(i);
+      if (!Elt)
+        return false;
+      if (isa<UndefValue>(Elt))
+        continue;
+      auto *CElt = dyn_cast<ConstantFP>(Elt);
+      if (!CElt || CElt->isInfinity())
+        return false;
+    }
+    // All elements were confirmed non-infinity or undefined.
+    return true;
+  }
+
+  // was not able to prove that V never contains infinity
+  return false;
+}
+
+bool llvm::isKnownNeverNaN(const Value *V, const TargetLibraryInfo *TLI,
+                           unsigned Depth) {
+  assert(V->getType()->isFPOrFPVectorTy() && "Querying for NaN on non-FP type");
+
+  // If we're told that NaNs won't happen, assume they won't.
+  if (auto *FPMathOp = dyn_cast<FPMathOperator>(V))
+    if (FPMathOp->hasNoNaNs())
+      return true;
+
+  // Handle scalar constants.
+  if (auto *CFP = dyn_cast<ConstantFP>(V))
+    return !CFP->isNaN();
+
+  if (Depth == MaxAnalysisRecursionDepth)
+    return false;
+
+  if (auto *Inst = dyn_cast<Instruction>(V)) {
+    switch (Inst->getOpcode()) {
+    case Instruction::FAdd:
+    case Instruction::FSub:
+      // Adding positive and negative infinity produces NaN.
+      return isKnownNeverNaN(Inst->getOperand(0), TLI, Depth + 1) &&
+             isKnownNeverNaN(Inst->getOperand(1), TLI, Depth + 1) &&
+             (isKnownNeverInfinity(Inst->getOperand(0), TLI, Depth + 1) ||
+              isKnownNeverInfinity(Inst->getOperand(1), TLI, Depth + 1));
+
+    case Instruction::FMul:
+      // Zero multiplied with infinity produces NaN.
+      // FIXME: If neither side can be zero fmul never produces NaN.
+      return isKnownNeverNaN(Inst->getOperand(0), TLI, Depth + 1) &&
+             isKnownNeverInfinity(Inst->getOperand(0), TLI, Depth + 1) &&
+             isKnownNeverNaN(Inst->getOperand(1), TLI, Depth + 1) &&
+             isKnownNeverInfinity(Inst->getOperand(1), TLI, Depth + 1);
+
+    case Instruction::FDiv:
+    case Instruction::FRem:
+      // FIXME: Only 0/0, Inf/Inf, Inf REM x and x REM 0 produce NaN.
+      return false;
+
+    case Instruction::Select: {
+      return isKnownNeverNaN(Inst->getOperand(1), TLI, Depth + 1) &&
+             isKnownNeverNaN(Inst->getOperand(2), TLI, Depth + 1);
+    }
+    case Instruction::SIToFP:
+    case Instruction::UIToFP:
+      return true;
+    case Instruction::FPTrunc:
+    case Instruction::FPExt:
+    case Instruction::FNeg:
+      return isKnownNeverNaN(Inst->getOperand(0), TLI, Depth + 1);
+    default:
+      break;
+    }
+  }
+
+  if (const auto *II = dyn_cast<IntrinsicInst>(V)) {
+    switch (II->getIntrinsicID()) {
+    case Intrinsic::canonicalize:
+    case Intrinsic::fabs:
+    case Intrinsic::copysign:
+    case Intrinsic::exp:
+    case Intrinsic::exp2:
+    case Intrinsic::floor:
+    case Intrinsic::ceil:
+    case Intrinsic::trunc:
+    case Intrinsic::rint:
+    case Intrinsic::nearbyint:
+    case Intrinsic::round:
+    case Intrinsic::roundeven:
+    case Intrinsic::arithmetic_fence:
+      return isKnownNeverNaN(II->getArgOperand(0), TLI, Depth + 1);
+    case Intrinsic::sqrt:
+      return isKnownNeverNaN(II->getArgOperand(0), TLI, Depth + 1) &&
+             CannotBeOrderedLessThanZero(II->getArgOperand(0), TLI);
+    case Intrinsic::minnum:
+    case Intrinsic::maxnum:
+      // If either operand is not NaN, the result is not NaN.
+      return isKnownNeverNaN(II->getArgOperand(0), TLI, Depth + 1) ||
+             isKnownNeverNaN(II->getArgOperand(1), TLI, Depth + 1);
+    default:
+      return false;
+    }
+  }
+
+  // Try to handle fixed width vector constants
+  auto *VFVTy = dyn_cast<FixedVectorType>(V->getType());
+  if (VFVTy && isa<Constant>(V)) {
+    // For vectors, verify that each element is not NaN.
+    unsigned NumElts = VFVTy->getNumElements();
+    for (unsigned i = 0; i != NumElts; ++i) {
+      Constant *Elt = cast<Constant>(V)->getAggregateElement(i);
+      if (!Elt)
+        return false;
+      if (isa<UndefValue>(Elt))
+        continue;
+      auto *CElt = dyn_cast<ConstantFP>(Elt);
+      if (!CElt || CElt->isNaN())
+        return false;
+    }
+    // All elements were confirmed not-NaN or undefined.
+    return true;
+  }
+
+  // Was not able to prove that V never contains NaN
+  return false;
+}
+
+Value *llvm::isBytewiseValue(Value *V, const DataLayout &DL) {
+
+  // All byte-wide stores are splatable, even of arbitrary variables.
+  if (V->getType()->isIntegerTy(8))
+    return V;
+
+  LLVMContext &Ctx = V->getContext();
+
+  // Undef don't care.
+  auto *UndefInt8 = UndefValue::get(Type::getInt8Ty(Ctx));
+  if (isa<UndefValue>(V))
+    return UndefInt8;
+
+  // Return Undef for zero-sized type.
+  if (!DL.getTypeStoreSize(V->getType()).isNonZero())
+    return UndefInt8;
+
+  Constant *C = dyn_cast<Constant>(V);
+  if (!C) {
+    // Conceptually, we could handle things like:
+    //   %a = zext i8 %X to i16
+    //   %b = shl i16 %a, 8
+    //   %c = or i16 %a, %b
+    // but until there is an example that actually needs this, it doesn't seem
+    // worth worrying about.
+    return nullptr;
+  }
+
+  // Handle 'null' ConstantArrayZero etc.
+  if (C->isNullValue())
+    return Constant::getNullValue(Type::getInt8Ty(Ctx));
+
+  // Constant floating-point values can be handled as integer values if the
+  // corresponding integer value is "byteable".  An important case is 0.0.
+  if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
+    Type *Ty = nullptr;
+    if (CFP->getType()->isHalfTy())
+      Ty = Type::getInt16Ty(Ctx);
+    else if (CFP->getType()->isFloatTy())
+      Ty = Type::getInt32Ty(Ctx);
+    else if (CFP->getType()->isDoubleTy())
+      Ty = Type::getInt64Ty(Ctx);
+    // Don't handle long double formats, which have strange constraints.
+    return Ty ? isBytewiseValue(ConstantExpr::getBitCast(CFP, Ty), DL)
+              : nullptr;
+  }
+
+  // We can handle constant integers that are multiple of 8 bits.
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
+    if (CI->getBitWidth() % 8 == 0) {
+      assert(CI->getBitWidth() > 8 && "8 bits should be handled above!");
+      if (!CI->getValue().isSplat(8))
+        return nullptr;
+      return ConstantInt::get(Ctx, CI->getValue().trunc(8));
+    }
+  }
+
+  if (auto *CE = dyn_cast<ConstantExpr>(C)) {
+    if (CE->getOpcode() == Instruction::IntToPtr) {
+      if (auto *PtrTy = dyn_cast<PointerType>(CE->getType())) {
+        unsigned BitWidth = DL.getPointerSizeInBits(PtrTy->getAddressSpace());
+        return isBytewiseValue(
+            ConstantExpr::getIntegerCast(CE->getOperand(0),
+                                         Type::getIntNTy(Ctx, BitWidth), false),
+            DL);
+      }
+    }
+  }
+
+  auto Merge = [&](Value *LHS, Value *RHS) -> Value * {
+    if (LHS == RHS)
+      return LHS;
+    if (!LHS || !RHS)
+      return nullptr;
+    if (LHS == UndefInt8)
+      return RHS;
+    if (RHS == UndefInt8)
+      return LHS;
+    return nullptr;
+  };
+
+  if (ConstantDataSequential *CA = dyn_cast<ConstantDataSequential>(C)) {
+    Value *Val = UndefInt8;
+    for (unsigned I = 0, E = CA->getNumElements(); I != E; ++I)
+      if (!(Val = Merge(Val, isBytewiseValue(CA->getElementAsConstant(I), DL))))
+        return nullptr;
+    return Val;
+  }
+
+  if (isa<ConstantAggregate>(C)) {
+    Value *Val = UndefInt8;
+    for (unsigned I = 0, E = C->getNumOperands(); I != E; ++I)
+      if (!(Val = Merge(Val, isBytewiseValue(C->getOperand(I), DL))))
+        return nullptr;
+    return Val;
+  }
+
+  // Don't try to handle the handful of other constants.
+  return nullptr;
+}
+
+// This is the recursive version of BuildSubAggregate. It takes a few different
+// arguments. Idxs is the index within the nested struct From that we are
+// looking at now (which is of type IndexedType). IdxSkip is the number of
+// indices from Idxs that should be left out when inserting into the resulting
+// struct. To is the result struct built so far, new insertvalue instructions
+// build on that.
+static Value *BuildSubAggregate(Value *From, Value* To, Type *IndexedType,
+                                SmallVectorImpl<unsigned> &Idxs,
+                                unsigned IdxSkip,
+                                Instruction *InsertBefore) {
+  StructType *STy = dyn_cast<StructType>(IndexedType);
+  if (STy) {
+    // Save the original To argument so we can modify it
+    Value *OrigTo = To;
+    // General case, the type indexed by Idxs is a struct
+    for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
+      // Process each struct element recursively
+      Idxs.push_back(i);
+      Value *PrevTo = To;
+      To = BuildSubAggregate(From, To, STy->getElementType(i), Idxs, IdxSkip,
+                             InsertBefore);
+      Idxs.pop_back();
+      if (!To) {
+        // Couldn't find any inserted value for this index? Cleanup
+        while (PrevTo != OrigTo) {
+          InsertValueInst* Del = cast<InsertValueInst>(PrevTo);
+          PrevTo = Del->getAggregateOperand();
+          Del->eraseFromParent();
+        }
+        // Stop processing elements
+        break;
+      }
+    }
+    // If we successfully found a value for each of our subaggregates
+    if (To)
+      return To;
+  }
+  // Base case, the type indexed by SourceIdxs is not a struct, or not all of
+  // the struct's elements had a value that was inserted directly. In the latter
+  // case, perhaps we can't determine each of the subelements individually, but
+  // we might be able to find the complete struct somewhere.
+
+  // Find the value that is at that particular spot
+  Value *V = FindInsertedValue(From, Idxs);
+
+  if (!V)
+    return nullptr;
+
+  // Insert the value in the new (sub) aggregate
+  return InsertValueInst::Create(To, V, ArrayRef(Idxs).slice(IdxSkip), "tmp",
+                                 InsertBefore);
+}
+
+// This helper takes a nested struct and extracts a part of it (which is again a
+// struct) into a new value. For example, given the struct:
+// { a, { b, { c, d }, e } }
+// and the indices "1, 1" this returns
+// { c, d }.
+//
+// It does this by inserting an insertvalue for each element in the resulting
+// struct, as opposed to just inserting a single struct. This will only work if
+// each of the elements of the substruct are known (ie, inserted into From by an
+// insertvalue instruction somewhere).
+//
+// All inserted insertvalue instructions are inserted before InsertBefore
+static Value *BuildSubAggregate(Value *From, ArrayRef<unsigned> idx_range,
+                                Instruction *InsertBefore) {
+  assert(InsertBefore && "Must have someplace to insert!");
+  Type *IndexedType = ExtractValueInst::getIndexedType(From->getType(),
+                                                             idx_range);
+  Value *To = PoisonValue::get(IndexedType);
+  SmallVector<unsigned, 10> Idxs(idx_range.begin(), idx_range.end());
+  unsigned IdxSkip = Idxs.size();
+
+  return BuildSubAggregate(From, To, IndexedType, Idxs, IdxSkip, InsertBefore);
+}
+
+/// Given an aggregate and a sequence of indices, see if the scalar value
+/// indexed is already around as a register, for example if it was inserted
+/// directly into the aggregate.
+///
+/// If InsertBefore is not null, this function will duplicate (modified)
+/// insertvalues when a part of a nested struct is extracted.
+Value *llvm::FindInsertedValue(Value *V, ArrayRef<unsigned> idx_range,
+                               Instruction *InsertBefore) {
+  // Nothing to index? Just return V then (this is useful at the end of our
+  // recursion).
+  if (idx_range.empty())
+    return V;
+  // We have indices, so V should have an indexable type.
+  assert((V->getType()->isStructTy() || V->getType()->isArrayTy()) &&
+         "Not looking at a struct or array?");
+  assert(ExtractValueInst::getIndexedType(V->getType(), idx_range) &&
+         "Invalid indices for type?");
+
+  if (Constant *C = dyn_cast<Constant>(V)) {
+    C = C->getAggregateElement(idx_range[0]);
+    if (!C) return nullptr;
+    return FindInsertedValue(C, idx_range.slice(1), InsertBefore);
+  }
+
+  if (InsertValueInst *I = dyn_cast<InsertValueInst>(V)) {
+    // Loop the indices for the insertvalue instruction in parallel with the
+    // requested indices
+    const unsigned *req_idx = idx_range.begin();
+    for (const unsigned *i = I->idx_begin(), *e = I->idx_end();
+         i != e; ++i, ++req_idx) {
+      if (req_idx == idx_range.end()) {
+        // We can't handle this without inserting insertvalues
+        if (!InsertBefore)
+          return nullptr;
+
+        // The requested index identifies a part of a nested aggregate. Handle
+        // this specially. For example,
+        // %A = insertvalue { i32, {i32, i32 } } undef, i32 10, 1, 0
+        // %B = insertvalue { i32, {i32, i32 } } %A, i32 11, 1, 1
+        // %C = extractvalue {i32, { i32, i32 } } %B, 1
+        // This can be changed into
+        // %A = insertvalue {i32, i32 } undef, i32 10, 0
+        // %C = insertvalue {i32, i32 } %A, i32 11, 1
+        // which allows the unused 0,0 element from the nested struct to be
+        // removed.
+        return BuildSubAggregate(V, ArrayRef(idx_range.begin(), req_idx),
+                                 InsertBefore);
+      }
+
+      // This insert value inserts something else than what we are looking for.
+      // See if the (aggregate) value inserted into has the value we are
+      // looking for, then.
+      if (*req_idx != *i)
+        return FindInsertedValue(I->getAggregateOperand(), idx_range,
+                                 InsertBefore);
+    }
+    // If we end up here, the indices of the insertvalue match with those
+    // requested (though possibly only partially). Now we recursively look at
+    // the inserted value, passing any remaining indices.
+    return FindInsertedValue(I->getInsertedValueOperand(),
+                             ArrayRef(req_idx, idx_range.end()), InsertBefore);
+  }
+
+  if (ExtractValueInst *I = dyn_cast<ExtractValueInst>(V)) {
+    // If we're extracting a value from an aggregate that was extracted from
+    // something else, we can extract from that something else directly instead.
+    // However, we will need to chain I's indices with the requested indices.
+
+    // Calculate the number of indices required
+    unsigned size = I->getNumIndices() + idx_range.size();
+    // Allocate some space to put the new indices in
+    SmallVector<unsigned, 5> Idxs;
+    Idxs.reserve(size);
+    // Add indices from the extract value instruction
+    Idxs.append(I->idx_begin(), I->idx_end());
+
+    // Add requested indices
+    Idxs.append(idx_range.begin(), idx_range.end());
+
+    assert(Idxs.size() == size
+           && "Number of indices added not correct?");
+
+    return FindInsertedValue(I->getAggregateOperand(), Idxs, InsertBefore);
+  }
+  // Otherwise, we don't know (such as, extracting from a function return value
+  // or load instruction)
+  return nullptr;
+}
+
+bool llvm::isGEPBasedOnPointerToString(const GEPOperator *GEP,
+                                       unsigned CharSize) {
+  // Make sure the GEP has exactly three arguments.
+  if (GEP->getNumOperands() != 3)
+    return false;
+
+  // Make sure the index-ee is a pointer to array of \p CharSize integers.
+  // CharSize.
+  ArrayType *AT = dyn_cast<ArrayType>(GEP->getSourceElementType());
+  if (!AT || !AT->getElementType()->isIntegerTy(CharSize))
+    return false;
+
+  // Check to make sure that the first operand of the GEP is an integer and
+  // has value 0 so that we are sure we're indexing into the initializer.
+  const ConstantInt *FirstIdx = dyn_cast<ConstantInt>(GEP->getOperand(1));
+  if (!FirstIdx || !FirstIdx->isZero())
+    return false;
+
+  return true;
+}
+
+// If V refers to an initialized global constant, set Slice either to
+// its initializer if the size of its elements equals ElementSize, or,
+// for ElementSize == 8, to its representation as an array of unsiged
+// char. Return true on success.
+// Offset is in the unit "nr of ElementSize sized elements".
+bool llvm::getConstantDataArrayInfo(const Value *V,
+                                    ConstantDataArraySlice &Slice,
+                                    unsigned ElementSize, uint64_t Offset) {
+  assert(V && "V should not be null.");
+  assert((ElementSize % 8) == 0 &&
+         "ElementSize expected to be a multiple of the size of a byte.");
+  unsigned ElementSizeInBytes = ElementSize / 8;
+
+  // Drill down into the pointer expression V, ignoring any intervening
+  // casts, and determine the identity of the object it references along
+  // with the cumulative byte offset into it.
+  const GlobalVariable *GV =
+    dyn_cast<GlobalVariable>(getUnderlyingObject(V));
+  if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer())
+    // Fail if V is not based on constant global object.
+    return false;
+
+  const DataLayout &DL = GV->getParent()->getDataLayout();
+  APInt Off(DL.getIndexTypeSizeInBits(V->getType()), 0);
+
+  if (GV != V->stripAndAccumulateConstantOffsets(DL, Off,
+                                                 /*AllowNonInbounds*/ true))
+    // Fail if a constant offset could not be determined.
+    return false;
+
+  uint64_t StartIdx = Off.getLimitedValue();
+  if (StartIdx == UINT64_MAX)
+    // Fail if the constant offset is excessive.
+    return false;
+
+  // Off/StartIdx is in the unit of bytes. So we need to convert to number of
+  // elements. Simply bail out if that isn't possible.
+  if ((StartIdx % ElementSizeInBytes) != 0)
+    return false;
+
+  Offset += StartIdx / ElementSizeInBytes;
+  ConstantDataArray *Array = nullptr;
+  ArrayType *ArrayTy = nullptr;
+
+  if (GV->getInitializer()->isNullValue()) {
+    Type *GVTy = GV->getValueType();
+    uint64_t SizeInBytes = DL.getTypeStoreSize(GVTy).getFixedValue();
+    uint64_t Length = SizeInBytes / ElementSizeInBytes;
+
+    Slice.Array = nullptr;
+    Slice.Offset = 0;
+    // Return an empty Slice for undersized constants to let callers
+    // transform even undefined library calls into simpler, well-defined
+    // expressions.  This is preferable to making the calls although it
+    // prevents sanitizers from detecting such calls.
+    Slice.Length = Length < Offset ? 0 : Length - Offset;
+    return true;
+  }
+
+  auto *Init = const_cast<Constant *>(GV->getInitializer());
+  if (auto *ArrayInit = dyn_cast<ConstantDataArray>(Init)) {
+    Type *InitElTy = ArrayInit->getElementType();
+    if (InitElTy->isIntegerTy(ElementSize)) {
+      // If Init is an initializer for an array of the expected type
+      // and size, use it as is.
+      Array = ArrayInit;
+      ArrayTy = ArrayInit->getType();
+    }
+  }
+
+  if (!Array) {
+    if (ElementSize != 8)
+      // TODO: Handle conversions to larger integral types.
+      return false;
+
+    // Otherwise extract the portion of the initializer starting
+    // at Offset as an array of bytes, and reset Offset.
+    Init = ReadByteArrayFromGlobal(GV, Offset);
+    if (!Init)
+      return false;
+
+    Offset = 0;
+    Array = dyn_cast<ConstantDataArray>(Init);
+    ArrayTy = dyn_cast<ArrayType>(Init->getType());
+  }
+
+  uint64_t NumElts = ArrayTy->getArrayNumElements();
+  if (Offset > NumElts)
+    return false;
+
+  Slice.Array = Array;
+  Slice.Offset = Offset;
+  Slice.Length = NumElts - Offset;
+  return true;
+}
+
+/// Extract bytes from the initializer of the constant array V, which need
+/// not be a nul-terminated string.  On success, store the bytes in Str and
+/// return true.  When TrimAtNul is set, Str will contain only the bytes up
+/// to but not including the first nul.  Return false on failure.
+bool llvm::getConstantStringInfo(const Value *V, StringRef &Str,
+                                 bool TrimAtNul) {
+  ConstantDataArraySlice Slice;
+  if (!getConstantDataArrayInfo(V, Slice, 8))
+    return false;
+
+  if (Slice.Array == nullptr) {
+    if (TrimAtNul) {
+      // Return a nul-terminated string even for an empty Slice.  This is
+      // safe because all existing SimplifyLibcalls callers require string
+      // arguments and the behavior of the functions they fold is undefined
+      // otherwise.  Folding the calls this way is preferable to making
+      // the undefined library calls, even though it prevents sanitizers
+      // from reporting such calls.
+      Str = StringRef();
+      return true;
+    }
+    if (Slice.Length == 1) {
+      Str = StringRef("", 1);
+      return true;
+    }
+    // We cannot instantiate a StringRef as we do not have an appropriate string
+    // of 0s at hand.
+    return false;
+  }
+
+  // Start out with the entire array in the StringRef.
+  Str = Slice.Array->getAsString();
+  // Skip over 'offset' bytes.
+  Str = Str.substr(Slice.Offset);
+
+  if (TrimAtNul) {
+    // Trim off the \0 and anything after it.  If the array is not nul
+    // terminated, we just return the whole end of string.  The client may know
+    // some other way that the string is length-bound.
+    Str = Str.substr(0, Str.find('\0'));
+  }
+  return true;
+}
+
+// These next two are very similar to the above, but also look through PHI
+// nodes.
+// TODO: See if we can integrate these two together.
+
+/// If we can compute the length of the string pointed to by
+/// the specified pointer, return 'len+1'.  If we can't, return 0.
+static uint64_t GetStringLengthH(const Value *V,
+                                 SmallPtrSetImpl<const PHINode*> &PHIs,
+                                 unsigned CharSize) {
+  // Look through noop bitcast instructions.
+  V = V->stripPointerCasts();
+
+  // If this is a PHI node, there are two cases: either we have already seen it
+  // or we haven't.
+  if (const PHINode *PN = dyn_cast<PHINode>(V)) {
+    if (!PHIs.insert(PN).second)
+      return ~0ULL;  // already in the set.
+
+    // If it was new, see if all the input strings are the same length.
+    uint64_t LenSoFar = ~0ULL;
+    for (Value *IncValue : PN->incoming_values()) {
+      uint64_t Len = GetStringLengthH(IncValue, PHIs, CharSize);
+      if (Len == 0) return 0; // Unknown length -> unknown.
+
+      if (Len == ~0ULL) continue;
+
+      if (Len != LenSoFar && LenSoFar != ~0ULL)
+        return 0;    // Disagree -> unknown.
+      LenSoFar = Len;
+    }
+
+    // Success, all agree.
+    return LenSoFar;
+  }
+
+  // strlen(select(c,x,y)) -> strlen(x) ^ strlen(y)
+  if (const SelectInst *SI = dyn_cast<SelectInst>(V)) {
+    uint64_t Len1 = GetStringLengthH(SI->getTrueValue(), PHIs, CharSize);
+    if (Len1 == 0) return 0;
+    uint64_t Len2 = GetStringLengthH(SI->getFalseValue(), PHIs, CharSize);
+    if (Len2 == 0) return 0;
+    if (Len1 == ~0ULL) return Len2;
+    if (Len2 == ~0ULL) return Len1;
+    if (Len1 != Len2) return 0;
+    return Len1;
+  }
+
+  // Otherwise, see if we can read the string.
+  ConstantDataArraySlice Slice;
+  if (!getConstantDataArrayInfo(V, Slice, CharSize))
+    return 0;
+
+  if (Slice.Array == nullptr)
+    // Zeroinitializer (including an empty one).
+    return 1;
+
+  // Search for the first nul character.  Return a conservative result even
+  // when there is no nul.  This is safe since otherwise the string function
+  // being folded such as strlen is undefined, and can be preferable to
+  // making the undefined library call.
+  unsigned NullIndex = 0;
+  for (unsigned E = Slice.Length; NullIndex < E; ++NullIndex) {
+    if (Slice.Array->getElementAsInteger(Slice.Offset + NullIndex) == 0)
+      break;
+  }
+
+  return NullIndex + 1;
+}
+
+/// If we can compute the length of the string pointed to by
+/// the specified pointer, return 'len+1'.  If we can't, return 0.
+uint64_t llvm::GetStringLength(const Value *V, unsigned CharSize) {
+  if (!V->getType()->isPointerTy())
+    return 0;
+
+  SmallPtrSet<const PHINode*, 32> PHIs;
+  uint64_t Len = GetStringLengthH(V, PHIs, CharSize);
+  // If Len is ~0ULL, we had an infinite phi cycle: this is dead code, so return
+  // an empty string as a length.
+  return Len == ~0ULL ? 1 : Len;
+}
+
+const Value *
+llvm::getArgumentAliasingToReturnedPointer(const CallBase *Call,
+                                           bool MustPreserveNullness) {
+  assert(Call &&
+         "getArgumentAliasingToReturnedPointer only works on nonnull calls");
+  if (const Value *RV = Call->getReturnedArgOperand())
+    return RV;
+  // This can be used only as a aliasing property.
+  if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
+          Call, MustPreserveNullness))
+    return Call->getArgOperand(0);
+  return nullptr;
+}
+
+bool llvm::isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
+    const CallBase *Call, bool MustPreserveNullness) {
+  switch (Call->getIntrinsicID()) {
+  case Intrinsic::launder_invariant_group:
+  case Intrinsic::strip_invariant_group:
+  case Intrinsic::aarch64_irg:
+  case Intrinsic::aarch64_tagp:
+    return true;
+  case Intrinsic::ptrmask:
+    return !MustPreserveNullness;
+  default:
+    return false;
+  }
+}
+
+/// \p PN defines a loop-variant pointer to an object.  Check if the
+/// previous iteration of the loop was referring to the same object as \p PN.
+static bool isSameUnderlyingObjectInLoop(const PHINode *PN,
+                                         const LoopInfo *LI) {
+  // Find the loop-defined value.
+  Loop *L = LI->getLoopFor(PN->getParent());
+  if (PN->getNumIncomingValues() != 2)
+    return true;
+
+  // Find the value from previous iteration.
+  auto *PrevValue = dyn_cast<Instruction>(PN->getIncomingValue(0));
+  if (!PrevValue || LI->getLoopFor(PrevValue->getParent()) != L)
+    PrevValue = dyn_cast<Instruction>(PN->getIncomingValue(1));
+  if (!PrevValue || LI->getLoopFor(PrevValue->getParent()) != L)
+    return true;
+
+  // If a new pointer is loaded in the loop, the pointer references a different
+  // object in every iteration.  E.g.:
+  //    for (i)
+  //       int *p = a[i];
+  //       ...
+  if (auto *Load = dyn_cast<LoadInst>(PrevValue))
+    if (!L->isLoopInvariant(Load->getPointerOperand()))
+      return false;
+  return true;
+}
+
+const Value *llvm::getUnderlyingObject(const Value *V, unsigned MaxLookup) {
+  if (!V->getType()->isPointerTy())
+    return V;
+  for (unsigned Count = 0; MaxLookup == 0 || Count < MaxLookup; ++Count) {
+    if (auto *GEP = dyn_cast<GEPOperator>(V)) {
+      V = GEP->getPointerOperand();
+    } else if (Operator::getOpcode(V) == Instruction::BitCast ||
+               Operator::getOpcode(V) == Instruction::AddrSpaceCast) {
+      V = cast<Operator>(V)->getOperand(0);
+      if (!V->getType()->isPointerTy())
+        return V;
+    } else if (auto *GA = dyn_cast<GlobalAlias>(V)) {
+      if (GA->isInterposable())
+        return V;
+      V = GA->getAliasee();
+    } else {
+      if (auto *PHI = dyn_cast<PHINode>(V)) {
+        // Look through single-arg phi nodes created by LCSSA.
+        if (PHI->getNumIncomingValues() == 1) {
+          V = PHI->getIncomingValue(0);
+          continue;
+        }
+      } else if (auto *Call = dyn_cast<CallBase>(V)) {
+        // CaptureTracking can know about special capturing properties of some
+        // intrinsics like launder.invariant.group, that can't be expressed with
+        // the attributes, but have properties like returning aliasing pointer.
+        // Because some analysis may assume that nocaptured pointer is not
+        // returned from some special intrinsic (because function would have to
+        // be marked with returns attribute), it is crucial to use this function
+        // because it should be in sync with CaptureTracking. Not using it may
+        // cause weird miscompilations where 2 aliasing pointers are assumed to
+        // noalias.
+        if (auto *RP = getArgumentAliasingToReturnedPointer(Call, false)) {
+          V = RP;
+          continue;
+        }
+      }
+
+      return V;
+    }
+    assert(V->getType()->isPointerTy() && "Unexpected operand type!");
+  }
+  return V;
+}
+
+void llvm::getUnderlyingObjects(const Value *V,
+                                SmallVectorImpl<const Value *> &Objects,
+                                LoopInfo *LI, unsigned MaxLookup) {
+  SmallPtrSet<const Value *, 4> Visited;
+  SmallVector<const Value *, 4> Worklist;
+  Worklist.push_back(V);
+  do {
+    const Value *P = Worklist.pop_back_val();
+    P = getUnderlyingObject(P, MaxLookup);
+
+    if (!Visited.insert(P).second)
+      continue;
+
+    if (auto *SI = dyn_cast<SelectInst>(P)) {
+      Worklist.push_back(SI->getTrueValue());
+      Worklist.push_back(SI->getFalseValue());
+      continue;
+    }
+
+    if (auto *PN = dyn_cast<PHINode>(P)) {
+      // If this PHI changes the underlying object in every iteration of the
+      // loop, don't look through it.  Consider:
+      //   int **A;
+      //   for (i) {
+      //     Prev = Curr;     // Prev = PHI (Prev_0, Curr)
+      //     Curr = A[i];
+      //     *Prev, *Curr;
+      //
+      // Prev is tracking Curr one iteration behind so they refer to different
+      // underlying objects.
+      if (!LI || !LI->isLoopHeader(PN->getParent()) ||
+          isSameUnderlyingObjectInLoop(PN, LI))
+        append_range(Worklist, PN->incoming_values());
+      continue;
+    }
+
+    Objects.push_back(P);
+  } while (!Worklist.empty());
+}
+
+/// This is the function that does the work of looking through basic
+/// ptrtoint+arithmetic+inttoptr sequences.
+static const Value *getUnderlyingObjectFromInt(const Value *V) {
+  do {
+    if (const Operator *U = dyn_cast<Operator>(V)) {
+      // If we find a ptrtoint, we can transfer control back to the
+      // regular getUnderlyingObjectFromInt.
+      if (U->getOpcode() == Instruction::PtrToInt)
+        return U->getOperand(0);
+      // If we find an add of a constant, a multiplied value, or a phi, it's
+      // likely that the other operand will lead us to the base
+      // object. We don't have to worry about the case where the
+      // object address is somehow being computed by the multiply,
+      // because our callers only care when the result is an
+      // identifiable object.
+      if (U->getOpcode() != Instruction::Add ||
+          (!isa<ConstantInt>(U->getOperand(1)) &&
+           Operator::getOpcode(U->getOperand(1)) != Instruction::Mul &&
+           !isa<PHINode>(U->getOperand(1))))
+        return V;
+      V = U->getOperand(0);
+    } else {
+      return V;
+    }
+    assert(V->getType()->isIntegerTy() && "Unexpected operand type!");
+  } while (true);
+}
+
+/// This is a wrapper around getUnderlyingObjects and adds support for basic
+/// ptrtoint+arithmetic+inttoptr sequences.
+/// It returns false if unidentified object is found in getUnderlyingObjects.
+bool llvm::getUnderlyingObjectsForCodeGen(const Value *V,
+                                          SmallVectorImpl<Value *> &Objects) {
+  SmallPtrSet<const Value *, 16> Visited;
+  SmallVector<const Value *, 4> Working(1, V);
+  do {
+    V = Working.pop_back_val();
+
+    SmallVector<const Value *, 4> Objs;
+    getUnderlyingObjects(V, Objs);
+
+    for (const Value *V : Objs) {
+      if (!Visited.insert(V).second)
+        continue;
+      if (Operator::getOpcode(V) == Instruction::IntToPtr) {
+        const Value *O =
+          getUnderlyingObjectFromInt(cast<User>(V)->getOperand(0));
+        if (O->getType()->isPointerTy()) {
+          Working.push_back(O);
+          continue;
+        }
+      }
+      // If getUnderlyingObjects fails to find an identifiable object,
+      // getUnderlyingObjectsForCodeGen also fails for safety.
+      if (!isIdentifiedObject(V)) {
+        Objects.clear();
+        return false;
+      }
+      Objects.push_back(const_cast<Value *>(V));
+    }
+  } while (!Working.empty());
+  return true;
+}
+
+AllocaInst *llvm::findAllocaForValue(Value *V, bool OffsetZero) {
+  AllocaInst *Result = nullptr;
+  SmallPtrSet<Value *, 4> Visited;
+  SmallVector<Value *, 4> Worklist;
+
+  auto AddWork = [&](Value *V) {
+    if (Visited.insert(V).second)
+      Worklist.push_back(V);
+  };
+
+  AddWork(V);
+  do {
+    V = Worklist.pop_back_val();
+    assert(Visited.count(V));
+
+    if (AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
+      if (Result && Result != AI)
+        return nullptr;
+      Result = AI;
+    } else if (CastInst *CI = dyn_cast<CastInst>(V)) {
+      AddWork(CI->getOperand(0));
+    } else if (PHINode *PN = dyn_cast<PHINode>(V)) {
+      for (Value *IncValue : PN->incoming_values())
+        AddWork(IncValue);
+    } else if (auto *SI = dyn_cast<SelectInst>(V)) {
+      AddWork(SI->getTrueValue());
+      AddWork(SI->getFalseValue());
+    } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) {
+      if (OffsetZero && !GEP->hasAllZeroIndices())
+        return nullptr;
+      AddWork(GEP->getPointerOperand());
+    } else if (CallBase *CB = dyn_cast<CallBase>(V)) {
+      Value *Returned = CB->getReturnedArgOperand();
+      if (Returned)
+        AddWork(Returned);
+      else
+        return nullptr;
+    } else {
+      return nullptr;
+    }
+  } while (!Worklist.empty());
+
+  return Result;
+}
+
+static bool onlyUsedByLifetimeMarkersOrDroppableInstsHelper(
+    const Value *V, bool AllowLifetime, bool AllowDroppable) {
+  for (const User *U : V->users()) {
+    const IntrinsicInst *II = dyn_cast<IntrinsicInst>(U);
+    if (!II)
+      return false;
+
+    if (AllowLifetime && II->isLifetimeStartOrEnd())
+      continue;
+
+    if (AllowDroppable && II->isDroppable())
+      continue;
+
+    return false;
+  }
+  return true;
+}
+
+bool llvm::onlyUsedByLifetimeMarkers(const Value *V) {
+  return onlyUsedByLifetimeMarkersOrDroppableInstsHelper(
+      V, /* AllowLifetime */ true, /* AllowDroppable */ false);
+}
+bool llvm::onlyUsedByLifetimeMarkersOrDroppableInsts(const Value *V) {
+  return onlyUsedByLifetimeMarkersOrDroppableInstsHelper(
+      V, /* AllowLifetime */ true, /* AllowDroppable */ true);
+}
+
+bool llvm::mustSuppressSpeculation(const LoadInst &LI) {
+  if (!LI.isUnordered())
+    return true;
+  const Function &F = *LI.getFunction();
+  // Speculative load may create a race that did not exist in the source.
+  return F.hasFnAttribute(Attribute::SanitizeThread) ||
+    // Speculative load may load data from dirty regions.
+    F.hasFnAttribute(Attribute::SanitizeAddress) ||
+    F.hasFnAttribute(Attribute::SanitizeHWAddress);
+}
+
+bool llvm::isSafeToSpeculativelyExecute(const Instruction *Inst,
+                                        const Instruction *CtxI,
+                                        AssumptionCache *AC,
+                                        const DominatorTree *DT,
+                                        const TargetLibraryInfo *TLI) {
+  return isSafeToSpeculativelyExecuteWithOpcode(Inst->getOpcode(), Inst, CtxI,
+                                                AC, DT, TLI);
+}
+
+bool llvm::isSafeToSpeculativelyExecuteWithOpcode(
+    unsigned Opcode, const Instruction *Inst, const Instruction *CtxI,
+    AssumptionCache *AC, const DominatorTree *DT,
+    const TargetLibraryInfo *TLI) {
+#ifndef NDEBUG
+  if (Inst->getOpcode() != Opcode) {
+    // Check that the operands are actually compatible with the Opcode override.
+    auto hasEqualReturnAndLeadingOperandTypes =
+        [](const Instruction *Inst, unsigned NumLeadingOperands) {
+          if (Inst->getNumOperands() < NumLeadingOperands)
+            return false;
+          const Type *ExpectedType = Inst->getType();
+          for (unsigned ItOp = 0; ItOp < NumLeadingOperands; ++ItOp)
+            if (Inst->getOperand(ItOp)->getType() != ExpectedType)
+              return false;
+          return true;
+        };
+    assert(!Instruction::isBinaryOp(Opcode) ||
+           hasEqualReturnAndLeadingOperandTypes(Inst, 2));
+    assert(!Instruction::isUnaryOp(Opcode) ||
+           hasEqualReturnAndLeadingOperandTypes(Inst, 1));
+  }
+#endif
+
+  switch (Opcode) {
+  default:
+    return true;
+  case Instruction::UDiv:
+  case Instruction::URem: {
+    // x / y is undefined if y == 0.
+    const APInt *V;
+    if (match(Inst->getOperand(1), m_APInt(V)))
+      return *V != 0;
+    return false;
+  }
+  case Instruction::SDiv:
+  case Instruction::SRem: {
+    // x / y is undefined if y == 0 or x == INT_MIN and y == -1
+    const APInt *Numerator, *Denominator;
+    if (!match(Inst->getOperand(1), m_APInt(Denominator)))
+      return false;
+    // We cannot hoist this division if the denominator is 0.
+    if (*Denominator == 0)
+      return false;
+    // It's safe to hoist if the denominator is not 0 or -1.
+    if (!Denominator->isAllOnes())
+      return true;
+    // At this point we know that the denominator is -1.  It is safe to hoist as
+    // long we know that the numerator is not INT_MIN.
+    if (match(Inst->getOperand(0), m_APInt(Numerator)))
+      return !Numerator->isMinSignedValue();
+    // The numerator *might* be MinSignedValue.
+    return false;
+  }
+  case Instruction::Load: {
+    const LoadInst *LI = dyn_cast<LoadInst>(Inst);
+    if (!LI)
+      return false;
+    if (mustSuppressSpeculation(*LI))
+      return false;
+    const DataLayout &DL = LI->getModule()->getDataLayout();
+    return isDereferenceableAndAlignedPointer(LI->getPointerOperand(),
+                                              LI->getType(), LI->getAlign(), DL,
+                                              CtxI, AC, DT, TLI);
+  }
+  case Instruction::Call: {
+    auto *CI = dyn_cast<const CallInst>(Inst);
+    if (!CI)
+      return false;
+    const Function *Callee = CI->getCalledFunction();
+
+    // The called function could have undefined behavior or side-effects, even
+    // if marked readnone nounwind.
+    return Callee && Callee->isSpeculatable();
+  }
+  case Instruction::VAArg:
+  case Instruction::Alloca:
+  case Instruction::Invoke:
+  case Instruction::CallBr:
+  case Instruction::PHI:
+  case Instruction::Store:
+  case Instruction::Ret:
+  case Instruction::Br:
+  case Instruction::IndirectBr:
+  case Instruction::Switch:
+  case Instruction::Unreachable:
+  case Instruction::Fence:
+  case Instruction::AtomicRMW:
+  case Instruction::AtomicCmpXchg:
+  case Instruction::LandingPad:
+  case Instruction::Resume:
+  case Instruction::CatchSwitch:
+  case Instruction::CatchPad:
+  case Instruction::CatchRet:
+  case Instruction::CleanupPad:
+  case Instruction::CleanupRet:
+    return false; // Misc instructions which have effects
+  }
+}
+
+bool llvm::mayHaveNonDefUseDependency(const Instruction &I) {
+  if (I.mayReadOrWriteMemory())
+    // Memory dependency possible
+    return true;
+  if (!isSafeToSpeculativelyExecute(&I))
+    // Can't move above a maythrow call or infinite loop.  Or if an
+    // inalloca alloca, above a stacksave call.
+    return true;
+  if (!isGuaranteedToTransferExecutionToSuccessor(&I))
+    // 1) Can't reorder two inf-loop calls, even if readonly
+    // 2) Also can't reorder an inf-loop call below a instruction which isn't
+    //    safe to speculative execute.  (Inverse of above)
+    return true;
+  return false;
+}
+
+/// Convert ConstantRange OverflowResult into ValueTracking OverflowResult.
+static OverflowResult mapOverflowResult(ConstantRange::OverflowResult OR) {
+  switch (OR) {
+    case ConstantRange::OverflowResult::MayOverflow:
+      return OverflowResult::MayOverflow;
+    case ConstantRange::OverflowResult::AlwaysOverflowsLow:
+      return OverflowResult::AlwaysOverflowsLow;
+    case ConstantRange::OverflowResult::AlwaysOverflowsHigh:
+      return OverflowResult::AlwaysOverflowsHigh;
+    case ConstantRange::OverflowResult::NeverOverflows:
+      return OverflowResult::NeverOverflows;
+  }
+  llvm_unreachable("Unknown OverflowResult");
+}
+
+/// Combine constant ranges from computeConstantRange() and computeKnownBits().
+static ConstantRange computeConstantRangeIncludingKnownBits(
+    const Value *V, bool ForSigned, const DataLayout &DL, unsigned Depth,
+    AssumptionCache *AC, const Instruction *CxtI, const DominatorTree *DT,
+    OptimizationRemarkEmitter *ORE = nullptr, bool UseInstrInfo = true) {
+  KnownBits Known = computeKnownBits(
+      V, DL, Depth, AC, CxtI, DT, ORE, UseInstrInfo);
+  ConstantRange CR1 = ConstantRange::fromKnownBits(Known, ForSigned);
+  ConstantRange CR2 = computeConstantRange(V, UseInstrInfo);
+  ConstantRange::PreferredRangeType RangeType =
+      ForSigned ? ConstantRange::Signed : ConstantRange::Unsigned;
+  return CR1.intersectWith(CR2, RangeType);
+}
+
+OverflowResult llvm::computeOverflowForUnsignedMul(
+    const Value *LHS, const Value *RHS, const DataLayout &DL,
+    AssumptionCache *AC, const Instruction *CxtI, const DominatorTree *DT,
+    bool UseInstrInfo) {
+  KnownBits LHSKnown = computeKnownBits(LHS, DL, /*Depth=*/0, AC, CxtI, DT,
+                                        nullptr, UseInstrInfo);
+  KnownBits RHSKnown = computeKnownBits(RHS, DL, /*Depth=*/0, AC, CxtI, DT,
+                                        nullptr, UseInstrInfo);
+  ConstantRange LHSRange = ConstantRange::fromKnownBits(LHSKnown, false);
+  ConstantRange RHSRange = ConstantRange::fromKnownBits(RHSKnown, false);
+  return mapOverflowResult(LHSRange.unsignedMulMayOverflow(RHSRange));
+}
+
+OverflowResult
+llvm::computeOverflowForSignedMul(const Value *LHS, const Value *RHS,
+                                  const DataLayout &DL, AssumptionCache *AC,
+                                  const Instruction *CxtI,
+                                  const DominatorTree *DT, bool UseInstrInfo) {
+  // Multiplying n * m significant bits yields a result of n + m significant
+  // bits. If the total number of significant bits does not exceed the
+  // result bit width (minus 1), there is no overflow.
+  // This means if we have enough leading sign bits in the operands
+  // we can guarantee that the result does not overflow.
+  // Ref: "Hacker's Delight" by Henry Warren
+  unsigned BitWidth = LHS->getType()->getScalarSizeInBits();
+
+  // Note that underestimating the number of sign bits gives a more
+  // conservative answer.
+  unsigned SignBits = ComputeNumSignBits(LHS, DL, 0, AC, CxtI, DT) +
+                      ComputeNumSignBits(RHS, DL, 0, AC, CxtI, DT);
+
+  // First handle the easy case: if we have enough sign bits there's
+  // definitely no overflow.
+  if (SignBits > BitWidth + 1)
+    return OverflowResult::NeverOverflows;
+
+  // There are two ambiguous cases where there can be no overflow:
+  //   SignBits == BitWidth + 1    and
+  //   SignBits == BitWidth
+  // The second case is difficult to check, therefore we only handle the
+  // first case.
+  if (SignBits == BitWidth + 1) {
+    // It overflows only when both arguments are negative and the true
+    // product is exactly the minimum negative number.
+    // E.g. mul i16 with 17 sign bits: 0xff00 * 0xff80 = 0x8000
+    // For simplicity we just check if at least one side is not negative.
+    KnownBits LHSKnown = computeKnownBits(LHS, DL, /*Depth=*/0, AC, CxtI, DT,
+                                          nullptr, UseInstrInfo);
+    KnownBits RHSKnown = computeKnownBits(RHS, DL, /*Depth=*/0, AC, CxtI, DT,
+                                          nullptr, UseInstrInfo);
+    if (LHSKnown.isNonNegative() || RHSKnown.isNonNegative())
+      return OverflowResult::NeverOverflows;
+  }
+  return OverflowResult::MayOverflow;
+}
+
+OverflowResult llvm::computeOverflowForUnsignedAdd(
+    const Value *LHS, const Value *RHS, const DataLayout &DL,
+    AssumptionCache *AC, const Instruction *CxtI, const DominatorTree *DT,
+    bool UseInstrInfo) {
+  ConstantRange LHSRange = computeConstantRangeIncludingKnownBits(
+      LHS, /*ForSigned=*/false, DL, /*Depth=*/0, AC, CxtI, DT,
+      nullptr, UseInstrInfo);
+  ConstantRange RHSRange = computeConstantRangeIncludingKnownBits(
+      RHS, /*ForSigned=*/false, DL, /*Depth=*/0, AC, CxtI, DT,
+      nullptr, UseInstrInfo);
+  return mapOverflowResult(LHSRange.unsignedAddMayOverflow(RHSRange));
+}
+
+static OverflowResult computeOverflowForSignedAdd(const Value *LHS,
+                                                  const Value *RHS,
+                                                  const AddOperator *Add,
+                                                  const DataLayout &DL,
+                                                  AssumptionCache *AC,
+                                                  const Instruction *CxtI,
+                                                  const DominatorTree *DT) {
+  if (Add && Add->hasNoSignedWrap()) {
+    return OverflowResult::NeverOverflows;
+  }
+
+  // If LHS and RHS each have at least two sign bits, the addition will look
+  // like
+  //
+  // XX..... +
+  // YY.....
+  //
+  // If the carry into the most significant position is 0, X and Y can't both
+  // be 1 and therefore the carry out of the addition is also 0.
+  //
+  // If the carry into the most significant position is 1, X and Y can't both
+  // be 0 and therefore the carry out of the addition is also 1.
+  //
+  // Since the carry into the most significant position is always equal to
+  // the carry out of the addition, there is no signed overflow.
+  if (ComputeNumSignBits(LHS, DL, 0, AC, CxtI, DT) > 1 &&
+      ComputeNumSignBits(RHS, DL, 0, AC, CxtI, DT) > 1)
+    return OverflowResult::NeverOverflows;
+
+  ConstantRange LHSRange = computeConstantRangeIncludingKnownBits(
+      LHS, /*ForSigned=*/true, DL, /*Depth=*/0, AC, CxtI, DT);
+  ConstantRange RHSRange = computeConstantRangeIncludingKnownBits(
+      RHS, /*ForSigned=*/true, DL, /*Depth=*/0, AC, CxtI, DT);
+  OverflowResult OR =
+      mapOverflowResult(LHSRange.signedAddMayOverflow(RHSRange));
+  if (OR != OverflowResult::MayOverflow)
+    return OR;
+
+  // The remaining code needs Add to be available. Early returns if not so.
+  if (!Add)
+    return OverflowResult::MayOverflow;
+
+  // If the sign of Add is the same as at least one of the operands, this add
+  // CANNOT overflow. If this can be determined from the known bits of the
+  // operands the above signedAddMayOverflow() check will have already done so.
+  // The only other way to improve on the known bits is from an assumption, so
+  // call computeKnownBitsFromAssume() directly.
+  bool LHSOrRHSKnownNonNegative =
+      (LHSRange.isAllNonNegative() || RHSRange.isAllNonNegative());
+  bool LHSOrRHSKnownNegative =
+      (LHSRange.isAllNegative() || RHSRange.isAllNegative());
+  if (LHSOrRHSKnownNonNegative || LHSOrRHSKnownNegative) {
+    KnownBits AddKnown(LHSRange.getBitWidth());
+    computeKnownBitsFromAssume(
+        Add, AddKnown, /*Depth=*/0, Query(DL, AC, CxtI, DT, true));
+    if ((AddKnown.isNonNegative() && LHSOrRHSKnownNonNegative) ||
+        (AddKnown.isNegative() && LHSOrRHSKnownNegative))
+      return OverflowResult::NeverOverflows;
+  }
+
+  return OverflowResult::MayOverflow;
+}
+
+OverflowResult llvm::computeOverflowForUnsignedSub(const Value *LHS,
+                                                   const Value *RHS,
+                                                   const DataLayout &DL,
+                                                   AssumptionCache *AC,
+                                                   const Instruction *CxtI,
+                                                   const DominatorTree *DT) {
+  // X - (X % ?)
+  // The remainder of a value can't have greater magnitude than itself,
+  // so the subtraction can't overflow.
+
+  // X - (X -nuw ?)
+  // In the minimal case, this would simplify to "?", so there's no subtract
+  // at all. But if this analysis is used to peek through casts, for example,
+  // then determining no-overflow may allow other transforms.
+
+  // TODO: There are other patterns like this.
+  //       See simplifyICmpWithBinOpOnLHS() for candidates.
+  if (match(RHS, m_URem(m_Specific(LHS), m_Value())) ||
+      match(RHS, m_NUWSub(m_Specific(LHS), m_Value())))
+    if (isGuaranteedNotToBeUndefOrPoison(LHS, AC, CxtI, DT))
+      return OverflowResult::NeverOverflows;
+
+  // Checking for conditions implied by dominating conditions may be expensive.
+  // Limit it to usub_with_overflow calls for now.
+  if (match(CxtI,
+            m_Intrinsic<Intrinsic::usub_with_overflow>(m_Value(), m_Value())))
+    if (auto C =
+            isImpliedByDomCondition(CmpInst::ICMP_UGE, LHS, RHS, CxtI, DL)) {
+      if (*C)
+        return OverflowResult::NeverOverflows;
+      return OverflowResult::AlwaysOverflowsLow;
+    }
+  ConstantRange LHSRange = computeConstantRangeIncludingKnownBits(
+      LHS, /*ForSigned=*/false, DL, /*Depth=*/0, AC, CxtI, DT);
+  ConstantRange RHSRange = computeConstantRangeIncludingKnownBits(
+      RHS, /*ForSigned=*/false, DL, /*Depth=*/0, AC, CxtI, DT);
+  return mapOverflowResult(LHSRange.unsignedSubMayOverflow(RHSRange));
+}
+
+OverflowResult llvm::computeOverflowForSignedSub(const Value *LHS,
+                                                 const Value *RHS,
+                                                 const DataLayout &DL,
+                                                 AssumptionCache *AC,
+                                                 const Instruction *CxtI,
+                                                 const DominatorTree *DT) {
+  // X - (X % ?)
+  // The remainder of a value can't have greater magnitude than itself,
+  // so the subtraction can't overflow.
+
+  // X - (X -nsw ?)
+  // In the minimal case, this would simplify to "?", so there's no subtract
+  // at all. But if this analysis is used to peek through casts, for example,
+  // then determining no-overflow may allow other transforms.
+  if (match(RHS, m_SRem(m_Specific(LHS), m_Value())) ||
+      match(RHS, m_NSWSub(m_Specific(LHS), m_Value())))
+    if (isGuaranteedNotToBeUndefOrPoison(LHS, AC, CxtI, DT))
+      return OverflowResult::NeverOverflows;
+
+  // If LHS and RHS each have at least two sign bits, the subtraction
+  // cannot overflow.
+  if (ComputeNumSignBits(LHS, DL, 0, AC, CxtI, DT) > 1 &&
+      ComputeNumSignBits(RHS, DL, 0, AC, CxtI, DT) > 1)
+    return OverflowResult::NeverOverflows;
+
+  ConstantRange LHSRange = computeConstantRangeIncludingKnownBits(
+      LHS, /*ForSigned=*/true, DL, /*Depth=*/0, AC, CxtI, DT);
+  ConstantRange RHSRange = computeConstantRangeIncludingKnownBits(
+      RHS, /*ForSigned=*/true, DL, /*Depth=*/0, AC, CxtI, DT);
+  return mapOverflowResult(LHSRange.signedSubMayOverflow(RHSRange));
+}
+
+bool llvm::isOverflowIntrinsicNoWrap(const WithOverflowInst *WO,
+                                     const DominatorTree &DT) {
+  SmallVector<const BranchInst *, 2> GuardingBranches;
+  SmallVector<const ExtractValueInst *, 2> Results;
+
+  for (const User *U : WO->users()) {
+    if (const auto *EVI = dyn_cast<ExtractValueInst>(U)) {
+      assert(EVI->getNumIndices() == 1 && "Obvious from CI's type");
+
+      if (EVI->getIndices()[0] == 0)
+        Results.push_back(EVI);
+      else {
+        assert(EVI->getIndices()[0] == 1 && "Obvious from CI's type");
+
+        for (const auto *U : EVI->users())
+          if (const auto *B = dyn_cast<BranchInst>(U)) {
+            assert(B->isConditional() && "How else is it using an i1?");
+            GuardingBranches.push_back(B);
+          }
+      }
+    } else {
+      // We are using the aggregate directly in a way we don't want to analyze
+      // here (storing it to a global, say).
+      return false;
+    }
+  }
+
+  auto AllUsesGuardedByBranch = [&](const BranchInst *BI) {
+    BasicBlockEdge NoWrapEdge(BI->getParent(), BI->getSuccessor(1));
+    if (!NoWrapEdge.isSingleEdge())
+      return false;
+
+    // Check if all users of the add are provably no-wrap.
+    for (const auto *Result : Results) {
+      // If the extractvalue itself is not executed on overflow, the we don't
+      // need to check each use separately, since domination is transitive.
+      if (DT.dominates(NoWrapEdge, Result->getParent()))
+        continue;
+
+      for (const auto &RU : Result->uses())
+        if (!DT.dominates(NoWrapEdge, RU))
+          return false;
+    }
+
+    return true;
+  };
+
+  return llvm::any_of(GuardingBranches, AllUsesGuardedByBranch);
+}
+
+/// Shifts return poison if shiftwidth is larger than the bitwidth.
+static bool shiftAmountKnownInRange(const Value *ShiftAmount) {
+  auto *C = dyn_cast<Constant>(ShiftAmount);
+  if (!C)
+    return false;
+
+  // Shifts return poison if shiftwidth is larger than the bitwidth.
+  SmallVector<const Constant *, 4> ShiftAmounts;
+  if (auto *FVTy = dyn_cast<FixedVectorType>(C->getType())) {
+    unsigned NumElts = FVTy->getNumElements();
+    for (unsigned i = 0; i < NumElts; ++i)
+      ShiftAmounts.push_back(C->getAggregateElement(i));
+  } else if (isa<ScalableVectorType>(C->getType()))
+    return false; // Can't tell, just return false to be safe
+  else
+    ShiftAmounts.push_back(C);
+
+  bool Safe = llvm::all_of(ShiftAmounts, [](const Constant *C) {
+    auto *CI = dyn_cast_or_null<ConstantInt>(C);
+    return CI && CI->getValue().ult(C->getType()->getIntegerBitWidth());
+  });
+
+  return Safe;
+}
+
+static bool canCreateUndefOrPoison(const Operator *Op, bool PoisonOnly,
+                                   bool ConsiderFlagsAndMetadata) {
+
+  if (ConsiderFlagsAndMetadata && Op->hasPoisonGeneratingFlagsOrMetadata())
+    return true;
+
+  unsigned Opcode = Op->getOpcode();
+
+  // Check whether opcode is a poison/undef-generating operation
+  switch (Opcode) {
+  case Instruction::Shl:
+  case Instruction::AShr:
+  case Instruction::LShr:
+    return !shiftAmountKnownInRange(Op->getOperand(1));
+  case Instruction::FPToSI:
+  case Instruction::FPToUI:
+    // fptosi/ui yields poison if the resulting value does not fit in the
+    // destination type.
+    return true;
+  case Instruction::Call:
+    if (auto *II = dyn_cast<IntrinsicInst>(Op)) {
+      switch (II->getIntrinsicID()) {
+      // TODO: Add more intrinsics.
+      case Intrinsic::ctlz:
+      case Intrinsic::cttz:
+      case Intrinsic::abs:
+        if (cast<ConstantInt>(II->getArgOperand(1))->isNullValue())
+          return false;
+        break;
+      case Intrinsic::ctpop:
+      case Intrinsic::bswap:
+      case Intrinsic::bitreverse:
+      case Intrinsic::fshl:
+      case Intrinsic::fshr:
+      case Intrinsic::smax:
+      case Intrinsic::smin:
+      case Intrinsic::umax:
+      case Intrinsic::umin:
+      case Intrinsic::ptrmask:
+      case Intrinsic::fptoui_sat:
+      case Intrinsic::fptosi_sat:
+      case Intrinsic::sadd_with_overflow:
+      case Intrinsic::ssub_with_overflow:
+      case Intrinsic::smul_with_overflow:
+      case Intrinsic::uadd_with_overflow:
+      case Intrinsic::usub_with_overflow:
+      case Intrinsic::umul_with_overflow:
+      case Intrinsic::sadd_sat:
+      case Intrinsic::uadd_sat:
+      case Intrinsic::ssub_sat:
+      case Intrinsic::usub_sat:
+        return false;
+      case Intrinsic::sshl_sat:
+      case Intrinsic::ushl_sat:
+        return !shiftAmountKnownInRange(II->getArgOperand(1));
+      case Intrinsic::fma:
+      case Intrinsic::fmuladd:
+      case Intrinsic::sqrt:
+      case Intrinsic::powi:
+      case Intrinsic::sin:
+      case Intrinsic::cos:
+      case Intrinsic::pow:
+      case Intrinsic::log:
+      case Intrinsic::log10:
+      case Intrinsic::log2:
+      case Intrinsic::exp:
+      case Intrinsic::exp2:
+      case Intrinsic::fabs:
+      case Intrinsic::copysign:
+      case Intrinsic::floor:
+      case Intrinsic::ceil:
+      case Intrinsic::trunc:
+      case Intrinsic::rint:
+      case Intrinsic::nearbyint:
+      case Intrinsic::round:
+      case Intrinsic::roundeven:
+      case Intrinsic::fptrunc_round:
+      case Intrinsic::canonicalize:
+      case Intrinsic::arithmetic_fence:
+      case Intrinsic::minnum:
+      case Intrinsic::maxnum:
+      case Intrinsic::minimum:
+      case Intrinsic::maximum:
+      case Intrinsic::is_fpclass:
+        return false;
+      case Intrinsic::lround:
+      case Intrinsic::llround:
+      case Intrinsic::lrint:
+      case Intrinsic::llrint:
+        // If the value doesn't fit an unspecified value is returned (but this
+        // is not poison).
+        return false;
+      }
+    }
+    [[fallthrough]];
+  case Instruction::CallBr:
+  case Instruction::Invoke: {
+    const auto *CB = cast<CallBase>(Op);
+    return !CB->hasRetAttr(Attribute::NoUndef);
+  }
+  case Instruction::InsertElement:
+  case Instruction::ExtractElement: {
+    // If index exceeds the length of the vector, it returns poison
+    auto *VTy = cast<VectorType>(Op->getOperand(0)->getType());
+    unsigned IdxOp = Op->getOpcode() == Instruction::InsertElement ? 2 : 1;
+    auto *Idx = dyn_cast<ConstantInt>(Op->getOperand(IdxOp));
+    if (!Idx || Idx->getValue().uge(VTy->getElementCount().getKnownMinValue()))
+      return true;
+    return false;
+  }
+  case Instruction::ShuffleVector: {
+    // shufflevector may return undef.
+    if (PoisonOnly)
+      return false;
+    ArrayRef<int> Mask = isa<ConstantExpr>(Op)
+                             ? cast<ConstantExpr>(Op)->getShuffleMask()
+                             : cast<ShuffleVectorInst>(Op)->getShuffleMask();
+    return is_contained(Mask, UndefMaskElem);
+  }
+  case Instruction::FNeg:
+  case Instruction::PHI:
+  case Instruction::Select:
+  case Instruction::URem:
+  case Instruction::SRem:
+  case Instruction::ExtractValue:
+  case Instruction::InsertValue:
+  case Instruction::Freeze:
+  case Instruction::ICmp:
+  case Instruction::FCmp:
+  case Instruction::FAdd:
+  case Instruction::FSub:
+  case Instruction::FMul:
+  case Instruction::FDiv:
+  case Instruction::FRem:
+    return false;
+  case Instruction::GetElementPtr:
+    // inbounds is handled above
+    // TODO: what about inrange on constexpr?
+    return false;
+  default: {
+    const auto *CE = dyn_cast<ConstantExpr>(Op);
+    if (isa<CastInst>(Op) || (CE && CE->isCast()))
+      return false;
+    else if (Instruction::isBinaryOp(Opcode))
+      return false;
+    // Be conservative and return true.
+    return true;
+  }
+  }
+}
+
+bool llvm::canCreateUndefOrPoison(const Operator *Op,
+                                  bool ConsiderFlagsAndMetadata) {
+  return ::canCreateUndefOrPoison(Op, /*PoisonOnly=*/false,
+                                  ConsiderFlagsAndMetadata);
+}
+
+bool llvm::canCreatePoison(const Operator *Op, bool ConsiderFlagsAndMetadata) {
+  return ::canCreateUndefOrPoison(Op, /*PoisonOnly=*/true,
+                                  ConsiderFlagsAndMetadata);
+}
+
+static bool directlyImpliesPoison(const Value *ValAssumedPoison,
+                                  const Value *V, unsigned Depth) {
+  if (ValAssumedPoison == V)
+    return true;
+
+  const unsigned MaxDepth = 2;
+  if (Depth >= MaxDepth)
+    return false;
+
+  if (const auto *I = dyn_cast<Instruction>(V)) {
+    if (any_of(I->operands(), [=](const Use &Op) {
+          return propagatesPoison(Op) &&
+                 directlyImpliesPoison(ValAssumedPoison, Op, Depth + 1);
+        }))
+      return true;
+
+    // V  = extractvalue V0, idx
+    // V2 = extractvalue V0, idx2
+    // V0's elements are all poison or not. (e.g., add_with_overflow)
+    const WithOverflowInst *II;
+    if (match(I, m_ExtractValue(m_WithOverflowInst(II))) &&
+        (match(ValAssumedPoison, m_ExtractValue(m_Specific(II))) ||
+         llvm::is_contained(II->args(), ValAssumedPoison)))
+      return true;
+  }
+  return false;
+}
+
+static bool impliesPoison(const Value *ValAssumedPoison, const Value *V,
+                          unsigned Depth) {
+  if (isGuaranteedNotToBeUndefOrPoison(ValAssumedPoison))
+    return true;
+
+  if (directlyImpliesPoison(ValAssumedPoison, V, /* Depth */ 0))
+    return true;
+
+  const unsigned MaxDepth = 2;
+  if (Depth >= MaxDepth)
+    return false;
+
+  const auto *I = dyn_cast<Instruction>(ValAssumedPoison);
+  if (I && !canCreatePoison(cast<Operator>(I))) {
+    return all_of(I->operands(), [=](const Value *Op) {
+      return impliesPoison(Op, V, Depth + 1);
+    });
+  }
+  return false;
+}
+
+bool llvm::impliesPoison(const Value *ValAssumedPoison, const Value *V) {
+  return ::impliesPoison(ValAssumedPoison, V, /* Depth */ 0);
+}
+
+static bool programUndefinedIfUndefOrPoison(const Value *V,
+                                            bool PoisonOnly);
+
+static bool isGuaranteedNotToBeUndefOrPoison(const Value *V,
+                                             AssumptionCache *AC,
+                                             const Instruction *CtxI,
+                                             const DominatorTree *DT,
+                                             unsigned Depth, bool PoisonOnly) {
+  if (Depth >= MaxAnalysisRecursionDepth)
+    return false;
+
+  if (isa<MetadataAsValue>(V))
+    return false;
+
+  if (const auto *A = dyn_cast<Argument>(V)) {
+    if (A->hasAttribute(Attribute::NoUndef))
+      return true;
+  }
+
+  if (auto *C = dyn_cast<Constant>(V)) {
+    if (isa<UndefValue>(C))
+      return PoisonOnly && !isa<PoisonValue>(C);
+
+    if (isa<ConstantInt>(C) || isa<GlobalVariable>(C) || isa<ConstantFP>(V) ||
+        isa<ConstantPointerNull>(C) || isa<Function>(C))
+      return true;
+
+    if (C->getType()->isVectorTy() && !isa<ConstantExpr>(C))
+      return (PoisonOnly ? !C->containsPoisonElement()
+                         : !C->containsUndefOrPoisonElement()) &&
+             !C->containsConstantExpression();
+  }
+
+  // Strip cast operations from a pointer value.
+  // Note that stripPointerCastsSameRepresentation can strip off getelementptr
+  // inbounds with zero offset. To guarantee that the result isn't poison, the
+  // stripped pointer is checked as it has to be pointing into an allocated
+  // object or be null `null` to ensure `inbounds` getelement pointers with a
+  // zero offset could not produce poison.
+  // It can strip off addrspacecast that do not change bit representation as
+  // well. We believe that such addrspacecast is equivalent to no-op.
+  auto *StrippedV = V->stripPointerCastsSameRepresentation();
+  if (isa<AllocaInst>(StrippedV) || isa<GlobalVariable>(StrippedV) ||
+      isa<Function>(StrippedV) || isa<ConstantPointerNull>(StrippedV))
+    return true;
+
+  auto OpCheck = [&](const Value *V) {
+    return isGuaranteedNotToBeUndefOrPoison(V, AC, CtxI, DT, Depth + 1,
+                                            PoisonOnly);
+  };
+
+  if (auto *Opr = dyn_cast<Operator>(V)) {
+    // If the value is a freeze instruction, then it can never
+    // be undef or poison.
+    if (isa<FreezeInst>(V))
+      return true;
+
+    if (const auto *CB = dyn_cast<CallBase>(V)) {
+      if (CB->hasRetAttr(Attribute::NoUndef))
+        return true;
+    }
+
+    if (const auto *PN = dyn_cast<PHINode>(V)) {
+      unsigned Num = PN->getNumIncomingValues();
+      bool IsWellDefined = true;
+      for (unsigned i = 0; i < Num; ++i) {
+        auto *TI = PN->getIncomingBlock(i)->getTerminator();
+        if (!isGuaranteedNotToBeUndefOrPoison(PN->getIncomingValue(i), AC, TI,
+                                              DT, Depth + 1, PoisonOnly)) {
+          IsWellDefined = false;
+          break;
+        }
+      }
+      if (IsWellDefined)
+        return true;
+    } else if (!canCreateUndefOrPoison(Opr) && all_of(Opr->operands(), OpCheck))
+      return true;
+  }
+
+  if (auto *I = dyn_cast<LoadInst>(V))
+    if (I->hasMetadata(LLVMContext::MD_noundef) ||
+        I->hasMetadata(LLVMContext::MD_dereferenceable) ||
+        I->hasMetadata(LLVMContext::MD_dereferenceable_or_null))
+      return true;
+
+  if (programUndefinedIfUndefOrPoison(V, PoisonOnly))
+    return true;
+
+  // CxtI may be null or a cloned instruction.
+  if (!CtxI || !CtxI->getParent() || !DT)
+    return false;
+
+  auto *DNode = DT->getNode(CtxI->getParent());
+  if (!DNode)
+    // Unreachable block
+    return false;
+
+  // If V is used as a branch condition before reaching CtxI, V cannot be
+  // undef or poison.
+  //   br V, BB1, BB2
+  // BB1:
+  //   CtxI ; V cannot be undef or poison here
+  auto *Dominator = DNode->getIDom();
+  while (Dominator) {
+    auto *TI = Dominator->getBlock()->getTerminator();
+
+    Value *Cond = nullptr;
+    if (auto BI = dyn_cast_or_null<BranchInst>(TI)) {
+      if (BI->isConditional())
+        Cond = BI->getCondition();
+    } else if (auto SI = dyn_cast_or_null<SwitchInst>(TI)) {
+      Cond = SI->getCondition();
+    }
+
+    if (Cond) {
+      if (Cond == V)
+        return true;
+      else if (PoisonOnly && isa<Operator>(Cond)) {
+        // For poison, we can analyze further
+        auto *Opr = cast<Operator>(Cond);
+        if (any_of(Opr->operands(),
+                   [V](const Use &U) { return V == U && propagatesPoison(U); }))
+          return true;
+      }
+    }
+
+    Dominator = Dominator->getIDom();
+  }
+
+  if (getKnowledgeValidInContext(V, {Attribute::NoUndef}, CtxI, DT, AC))
+    return true;
+
+  return false;
+}
+
+bool llvm::isGuaranteedNotToBeUndefOrPoison(const Value *V, AssumptionCache *AC,
+                                            const Instruction *CtxI,
+                                            const DominatorTree *DT,
+                                            unsigned Depth) {
+  return ::isGuaranteedNotToBeUndefOrPoison(V, AC, CtxI, DT, Depth, false);
+}
+
+bool llvm::isGuaranteedNotToBePoison(const Value *V, AssumptionCache *AC,
+                                     const Instruction *CtxI,
+                                     const DominatorTree *DT, unsigned Depth) {
+  return ::isGuaranteedNotToBeUndefOrPoison(V, AC, CtxI, DT, Depth, true);
+}
+
+OverflowResult llvm::computeOverflowForSignedAdd(const AddOperator *Add,
+                                                 const DataLayout &DL,
+                                                 AssumptionCache *AC,
+                                                 const Instruction *CxtI,
+                                                 const DominatorTree *DT) {
+  return ::computeOverflowForSignedAdd(Add->getOperand(0), Add->getOperand(1),
+                                       Add, DL, AC, CxtI, DT);
+}
+
+OverflowResult llvm::computeOverflowForSignedAdd(const Value *LHS,
+                                                 const Value *RHS,
+                                                 const DataLayout &DL,
+                                                 AssumptionCache *AC,
+                                                 const Instruction *CxtI,
+                                                 const DominatorTree *DT) {
+  return ::computeOverflowForSignedAdd(LHS, RHS, nullptr, DL, AC, CxtI, DT);
+}
+
+bool llvm::isGuaranteedToTransferExecutionToSuccessor(const Instruction *I) {
+  // Note: An atomic operation isn't guaranteed to return in a reasonable amount
+  // of time because it's possible for another thread to interfere with it for an
+  // arbitrary length of time, but programs aren't allowed to rely on that.
+
+  // If there is no successor, then execution can't transfer to it.
+  if (isa<ReturnInst>(I))
+    return false;
+  if (isa<UnreachableInst>(I))
+    return false;
+
+  // Note: Do not add new checks here; instead, change Instruction::mayThrow or
+  // Instruction::willReturn.
+  //
+  // FIXME: Move this check into Instruction::willReturn.
+  if (isa<CatchPadInst>(I)) {
+    switch (classifyEHPersonality(I->getFunction()->getPersonalityFn())) {
+    default:
+      // A catchpad may invoke exception object constructors and such, which
+      // in some languages can be arbitrary code, so be conservative by default.
+      return false;
+    case EHPersonality::CoreCLR:
+      // For CoreCLR, it just involves a type test.
+      return true;
+    }
+  }
+
+  // An instruction that returns without throwing must transfer control flow
+  // to a successor.
+  return !I->mayThrow() && I->willReturn();
+}
+
+bool llvm::isGuaranteedToTransferExecutionToSuccessor(const BasicBlock *BB) {
+  // TODO: This is slightly conservative for invoke instruction since exiting
+  // via an exception *is* normal control for them.
+  for (const Instruction &I : *BB)
+    if (!isGuaranteedToTransferExecutionToSuccessor(&I))
+      return false;
+  return true;
+}
+
+bool llvm::isGuaranteedToTransferExecutionToSuccessor(
+   BasicBlock::const_iterator Begin, BasicBlock::const_iterator End,
+   unsigned ScanLimit) {
+  return isGuaranteedToTransferExecutionToSuccessor(make_range(Begin, End),
+                                                    ScanLimit);
+}
+
+bool llvm::isGuaranteedToTransferExecutionToSuccessor(
+   iterator_range<BasicBlock::const_iterator> Range, unsigned ScanLimit) {
+  assert(ScanLimit && "scan limit must be non-zero");
+  for (const Instruction &I : Range) {
+    if (isa<DbgInfoIntrinsic>(I))
+        continue;
+    if (--ScanLimit == 0)
+      return false;
+    if (!isGuaranteedToTransferExecutionToSuccessor(&I))
+      return false;
+  }
+  return true;
+}
+
+bool llvm::isGuaranteedToExecuteForEveryIteration(const Instruction *I,
+                                                  const Loop *L) {
+  // The loop header is guaranteed to be executed for every iteration.
+  //
+  // FIXME: Relax this constraint to cover all basic blocks that are
+  // guaranteed to be executed at every iteration.
+  if (I->getParent() != L->getHeader()) return false;
+
+  for (const Instruction &LI : *L->getHeader()) {
+    if (&LI == I) return true;
+    if (!isGuaranteedToTransferExecutionToSuccessor(&LI)) return false;
+  }
+  llvm_unreachable("Instruction not contained in its own parent basic block.");
+}
+
+bool llvm::propagatesPoison(const Use &PoisonOp) {
+  const Operator *I = cast<Operator>(PoisonOp.getUser());
+  switch (I->getOpcode()) {
+  case Instruction::Freeze:
+  case Instruction::PHI:
+  case Instruction::Invoke:
+    return false;
+  case Instruction::Select:
+    return PoisonOp.getOperandNo() == 0;
+  case Instruction::Call:
+    if (auto *II = dyn_cast<IntrinsicInst>(I)) {
+      switch (II->getIntrinsicID()) {
+      // TODO: Add more intrinsics.
+      case Intrinsic::sadd_with_overflow:
+      case Intrinsic::ssub_with_overflow:
+      case Intrinsic::smul_with_overflow:
+      case Intrinsic::uadd_with_overflow:
+      case Intrinsic::usub_with_overflow:
+      case Intrinsic::umul_with_overflow:
+        // If an input is a vector containing a poison element, the
+        // two output vectors (calculated results, overflow bits)'
+        // corresponding lanes are poison.
+        return true;
+      case Intrinsic::ctpop:
+        return true;
+      }
+    }
+    return false;
+  case Instruction::ICmp:
+  case Instruction::FCmp:
+  case Instruction::GetElementPtr:
+    return true;
+  default:
+    if (isa<BinaryOperator>(I) || isa<UnaryOperator>(I) || isa<CastInst>(I))
+      return true;
+
+    // Be conservative and return false.
+    return false;
+  }
+}
+
+void llvm::getGuaranteedWellDefinedOps(
+    const Instruction *I, SmallVectorImpl<const Value *> &Operands) {
+  switch (I->getOpcode()) {
+    case Instruction::Store:
+      Operands.push_back(cast<StoreInst>(I)->getPointerOperand());
+      break;
+
+    case Instruction::Load:
+      Operands.push_back(cast<LoadInst>(I)->getPointerOperand());
+      break;
+
+    // Since dereferenceable attribute imply noundef, atomic operations
+    // also implicitly have noundef pointers too
+    case Instruction::AtomicCmpXchg:
+      Operands.push_back(cast<AtomicCmpXchgInst>(I)->getPointerOperand());
+      break;
+
+    case Instruction::AtomicRMW:
+      Operands.push_back(cast<AtomicRMWInst>(I)->getPointerOperand());
+      break;
+
+    case Instruction::Call:
+    case Instruction::Invoke: {
+      const CallBase *CB = cast<CallBase>(I);
+      if (CB->isIndirectCall())
+        Operands.push_back(CB->getCalledOperand());
+      for (unsigned i = 0; i < CB->arg_size(); ++i) {
+        if (CB->paramHasAttr(i, Attribute::NoUndef) ||
+            CB->paramHasAttr(i, Attribute::Dereferenceable))
+          Operands.push_back(CB->getArgOperand(i));
+      }
+      break;
+    }
+    case Instruction::Ret:
+      if (I->getFunction()->hasRetAttribute(Attribute::NoUndef))
+        Operands.push_back(I->getOperand(0));
+      break;
+    case Instruction::Switch:
+      Operands.push_back(cast<SwitchInst>(I)->getCondition());
+      break;
+    case Instruction::Br: {
+      auto *BR = cast<BranchInst>(I);
+      if (BR->isConditional())
+        Operands.push_back(BR->getCondition());
+      break;
+    }
+    default:
+      break;
+  }
+}
+
+void llvm::getGuaranteedNonPoisonOps(const Instruction *I,
+                                     SmallVectorImpl<const Value *> &Operands) {
+  getGuaranteedWellDefinedOps(I, Operands);
+  switch (I->getOpcode()) {
+  // Divisors of these operations are allowed to be partially undef.
+  case Instruction::UDiv:
+  case Instruction::SDiv:
+  case Instruction::URem:
+  case Instruction::SRem:
+    Operands.push_back(I->getOperand(1));
+    break;
+  default:
+    break;
+  }
+}
+
+bool llvm::mustTriggerUB(const Instruction *I,
+                         const SmallSet<const Value *, 16>& KnownPoison) {
+  SmallVector<const Value *, 4> NonPoisonOps;
+  getGuaranteedNonPoisonOps(I, NonPoisonOps);
+
+  for (const auto *V : NonPoisonOps)
+    if (KnownPoison.count(V))
+      return true;
+
+  return false;
+}
+
+static bool programUndefinedIfUndefOrPoison(const Value *V,
+                                            bool PoisonOnly) {
+  // We currently only look for uses of values within the same basic
+  // block, as that makes it easier to guarantee that the uses will be
+  // executed given that Inst is executed.
+  //
+  // FIXME: Expand this to consider uses beyond the same basic block. To do
+  // this, look out for the distinction between post-dominance and strong
+  // post-dominance.
+  const BasicBlock *BB = nullptr;
+  BasicBlock::const_iterator Begin;
+  if (const auto *Inst = dyn_cast<Instruction>(V)) {
+    BB = Inst->getParent();
+    Begin = Inst->getIterator();
+    Begin++;
+  } else if (const auto *Arg = dyn_cast<Argument>(V)) {
+    BB = &Arg->getParent()->getEntryBlock();
+    Begin = BB->begin();
+  } else {
+    return false;
+  }
+
+  // Limit number of instructions we look at, to avoid scanning through large
+  // blocks. The current limit is chosen arbitrarily.
+  unsigned ScanLimit = 32;
+  BasicBlock::const_iterator End = BB->end();
+
+  if (!PoisonOnly) {
+    // Since undef does not propagate eagerly, be conservative & just check
+    // whether a value is directly passed to an instruction that must take
+    // well-defined operands.
+
+    for (const auto &I : make_range(Begin, End)) {
+      if (isa<DbgInfoIntrinsic>(I))
+        continue;
+      if (--ScanLimit == 0)
+        break;
+
+      SmallVector<const Value *, 4> WellDefinedOps;
+      getGuaranteedWellDefinedOps(&I, WellDefinedOps);
+      if (is_contained(WellDefinedOps, V))
+        return true;
+
+      if (!isGuaranteedToTransferExecutionToSuccessor(&I))
+        break;
+    }
+    return false;
+  }
+
+  // Set of instructions that we have proved will yield poison if Inst
+  // does.
+  SmallSet<const Value *, 16> YieldsPoison;
+  SmallSet<const BasicBlock *, 4> Visited;
+
+  YieldsPoison.insert(V);
+  Visited.insert(BB);
+
+  while (true) {
+    for (const auto &I : make_range(Begin, End)) {
+      if (isa<DbgInfoIntrinsic>(I))
+        continue;
+      if (--ScanLimit == 0)
+        return false;
+      if (mustTriggerUB(&I, YieldsPoison))
+        return true;
+      if (!isGuaranteedToTransferExecutionToSuccessor(&I))
+        return false;
+
+      // If an operand is poison and propagates it, mark I as yielding poison.
+      for (const Use &Op : I.operands()) {
+        if (YieldsPoison.count(Op) && propagatesPoison(Op)) {
+          YieldsPoison.insert(&I);
+          break;
+        }
+      }
+    }
+
+    BB = BB->getSingleSuccessor();
+    if (!BB || !Visited.insert(BB).second)
+      break;
+
+    Begin = BB->getFirstNonPHI()->getIterator();
+    End = BB->end();
+  }
+  return false;
+}
+
+bool llvm::programUndefinedIfUndefOrPoison(const Instruction *Inst) {
+  return ::programUndefinedIfUndefOrPoison(Inst, false);
+}
+
+bool llvm::programUndefinedIfPoison(const Instruction *Inst) {
+  return ::programUndefinedIfUndefOrPoison(Inst, true);
+}
+
+static bool isKnownNonNaN(const Value *V, FastMathFlags FMF) {
+  if (FMF.noNaNs())
+    return true;
+
+  if (auto *C = dyn_cast<ConstantFP>(V))
+    return !C->isNaN();
+
+  if (auto *C = dyn_cast<ConstantDataVector>(V)) {
+    if (!C->getElementType()->isFloatingPointTy())
+      return false;
+    for (unsigned I = 0, E = C->getNumElements(); I < E; ++I) {
+      if (C->getElementAsAPFloat(I).isNaN())
+        return false;
+    }
+    return true;
+  }
+
+  if (isa<ConstantAggregateZero>(V))
+    return true;
+
+  return false;
+}
+
+static bool isKnownNonZero(const Value *V) {
+  if (auto *C = dyn_cast<ConstantFP>(V))
+    return !C->isZero();
+
+  if (auto *C = dyn_cast<ConstantDataVector>(V)) {
+    if (!C->getElementType()->isFloatingPointTy())
+      return false;
+    for (unsigned I = 0, E = C->getNumElements(); I < E; ++I) {
+      if (C->getElementAsAPFloat(I).isZero())
+        return false;
+    }
+    return true;
+  }
+
+  return false;
+}
+
+/// Match clamp pattern for float types without care about NaNs or signed zeros.
+/// Given non-min/max outer cmp/select from the clamp pattern this
+/// function recognizes if it can be substitued by a "canonical" min/max
+/// pattern.
+static SelectPatternResult matchFastFloatClamp(CmpInst::Predicate Pred,
+                                               Value *CmpLHS, Value *CmpRHS,
+                                               Value *TrueVal, Value *FalseVal,
+                                               Value *&LHS, Value *&RHS) {
+  // Try to match
+  //   X < C1 ? C1 : Min(X, C2) --> Max(C1, Min(X, C2))
+  //   X > C1 ? C1 : Max(X, C2) --> Min(C1, Max(X, C2))
+  // and return description of the outer Max/Min.
+
+  // First, check if select has inverse order:
+  if (CmpRHS == FalseVal) {
+    std::swap(TrueVal, FalseVal);
+    Pred = CmpInst::getInversePredicate(Pred);
+  }
+
+  // Assume success now. If there's no match, callers should not use these anyway.
+  LHS = TrueVal;
+  RHS = FalseVal;
+
+  const APFloat *FC1;
+  if (CmpRHS != TrueVal || !match(CmpRHS, m_APFloat(FC1)) || !FC1->isFinite())
+    return {SPF_UNKNOWN, SPNB_NA, false};
+
+  const APFloat *FC2;
+  switch (Pred) {
+  case CmpInst::FCMP_OLT:
+  case CmpInst::FCMP_OLE:
+  case CmpInst::FCMP_ULT:
+  case CmpInst::FCMP_ULE:
+    if (match(FalseVal,
+              m_CombineOr(m_OrdFMin(m_Specific(CmpLHS), m_APFloat(FC2)),
+                          m_UnordFMin(m_Specific(CmpLHS), m_APFloat(FC2)))) &&
+        *FC1 < *FC2)
+      return {SPF_FMAXNUM, SPNB_RETURNS_ANY, false};
+    break;
+  case CmpInst::FCMP_OGT:
+  case CmpInst::FCMP_OGE:
+  case CmpInst::FCMP_UGT:
+  case CmpInst::FCMP_UGE:
+    if (match(FalseVal,
+              m_CombineOr(m_OrdFMax(m_Specific(CmpLHS), m_APFloat(FC2)),
+                          m_UnordFMax(m_Specific(CmpLHS), m_APFloat(FC2)))) &&
+        *FC1 > *FC2)
+      return {SPF_FMINNUM, SPNB_RETURNS_ANY, false};
+    break;
+  default:
+    break;
+  }
+
+  return {SPF_UNKNOWN, SPNB_NA, false};
+}
+
+/// Recognize variations of:
+///   CLAMP(v,l,h) ==> ((v) < (l) ? (l) : ((v) > (h) ? (h) : (v)))
+static SelectPatternResult matchClamp(CmpInst::Predicate Pred,
+                                      Value *CmpLHS, Value *CmpRHS,
+                                      Value *TrueVal, Value *FalseVal) {
+  // Swap the select operands and predicate to match the patterns below.
+  if (CmpRHS != TrueVal) {
+    Pred = ICmpInst::getSwappedPredicate(Pred);
+    std::swap(TrueVal, FalseVal);
+  }
+  const APInt *C1;
+  if (CmpRHS == TrueVal && match(CmpRHS, m_APInt(C1))) {
+    const APInt *C2;
+    // (X <s C1) ? C1 : SMIN(X, C2) ==> SMAX(SMIN(X, C2), C1)
+    if (match(FalseVal, m_SMin(m_Specific(CmpLHS), m_APInt(C2))) &&
+        C1->slt(*C2) && Pred == CmpInst::ICMP_SLT)
+      return {SPF_SMAX, SPNB_NA, false};
+
+    // (X >s C1) ? C1 : SMAX(X, C2) ==> SMIN(SMAX(X, C2), C1)
+    if (match(FalseVal, m_SMax(m_Specific(CmpLHS), m_APInt(C2))) &&
+        C1->sgt(*C2) && Pred == CmpInst::ICMP_SGT)
+      return {SPF_SMIN, SPNB_NA, false};
+
+    // (X <u C1) ? C1 : UMIN(X, C2) ==> UMAX(UMIN(X, C2), C1)
+    if (match(FalseVal, m_UMin(m_Specific(CmpLHS), m_APInt(C2))) &&
+        C1->ult(*C2) && Pred == CmpInst::ICMP_ULT)
+      return {SPF_UMAX, SPNB_NA, false};
+
+    // (X >u C1) ? C1 : UMAX(X, C2) ==> UMIN(UMAX(X, C2), C1)
+    if (match(FalseVal, m_UMax(m_Specific(CmpLHS), m_APInt(C2))) &&
+        C1->ugt(*C2) && Pred == CmpInst::ICMP_UGT)
+      return {SPF_UMIN, SPNB_NA, false};
+  }
+  return {SPF_UNKNOWN, SPNB_NA, false};
+}
+
+/// Recognize variations of:
+///   a < c ? min(a,b) : min(b,c) ==> min(min(a,b),min(b,c))
+static SelectPatternResult matchMinMaxOfMinMax(CmpInst::Predicate Pred,
+                                               Value *CmpLHS, Value *CmpRHS,
+                                               Value *TVal, Value *FVal,
+                                               unsigned Depth) {
+  // TODO: Allow FP min/max with nnan/nsz.
+  assert(CmpInst::isIntPredicate(Pred) && "Expected integer comparison");
+
+  Value *A = nullptr, *B = nullptr;
+  SelectPatternResult L = matchSelectPattern(TVal, A, B, nullptr, Depth + 1);
+  if (!SelectPatternResult::isMinOrMax(L.Flavor))
+    return {SPF_UNKNOWN, SPNB_NA, false};
+
+  Value *C = nullptr, *D = nullptr;
+  SelectPatternResult R = matchSelectPattern(FVal, C, D, nullptr, Depth + 1);
+  if (L.Flavor != R.Flavor)
+    return {SPF_UNKNOWN, SPNB_NA, false};
+
+  // We have something like: x Pred y ? min(a, b) : min(c, d).
+  // Try to match the compare to the min/max operations of the select operands.
+  // First, make sure we have the right compare predicate.
+  switch (L.Flavor) {
+  case SPF_SMIN:
+    if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE) {
+      Pred = ICmpInst::getSwappedPredicate(Pred);
+      std::swap(CmpLHS, CmpRHS);
+    }
+    if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE)
+      break;
+    return {SPF_UNKNOWN, SPNB_NA, false};
+  case SPF_SMAX:
+    if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE) {
+      Pred = ICmpInst::getSwappedPredicate(Pred);
+      std::swap(CmpLHS, CmpRHS);
+    }
+    if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE)
+      break;
+    return {SPF_UNKNOWN, SPNB_NA, false};
+  case SPF_UMIN:
+    if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE) {
+      Pred = ICmpInst::getSwappedPredicate(Pred);
+      std::swap(CmpLHS, CmpRHS);
+    }
+    if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_ULE)
+      break;
+    return {SPF_UNKNOWN, SPNB_NA, false};
+  case SPF_UMAX:
+    if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_ULE) {
+      Pred = ICmpInst::getSwappedPredicate(Pred);
+      std::swap(CmpLHS, CmpRHS);
+    }
+    if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE)
+      break;
+    return {SPF_UNKNOWN, SPNB_NA, false};
+  default:
+    return {SPF_UNKNOWN, SPNB_NA, false};
+  }
+
+  // If there is a common operand in the already matched min/max and the other
+  // min/max operands match the compare operands (either directly or inverted),
+  // then this is min/max of the same flavor.
+
+  // a pred c ? m(a, b) : m(c, b) --> m(m(a, b), m(c, b))
+  // ~c pred ~a ? m(a, b) : m(c, b) --> m(m(a, b), m(c, b))
+  if (D == B) {
+    if ((CmpLHS == A && CmpRHS == C) || (match(C, m_Not(m_Specific(CmpLHS))) &&
+                                         match(A, m_Not(m_Specific(CmpRHS)))))
+      return {L.Flavor, SPNB_NA, false};
+  }
+  // a pred d ? m(a, b) : m(b, d) --> m(m(a, b), m(b, d))
+  // ~d pred ~a ? m(a, b) : m(b, d) --> m(m(a, b), m(b, d))
+  if (C == B) {
+    if ((CmpLHS == A && CmpRHS == D) || (match(D, m_Not(m_Specific(CmpLHS))) &&
+                                         match(A, m_Not(m_Specific(CmpRHS)))))
+      return {L.Flavor, SPNB_NA, false};
+  }
+  // b pred c ? m(a, b) : m(c, a) --> m(m(a, b), m(c, a))
+  // ~c pred ~b ? m(a, b) : m(c, a) --> m(m(a, b), m(c, a))
+  if (D == A) {
+    if ((CmpLHS == B && CmpRHS == C) || (match(C, m_Not(m_Specific(CmpLHS))) &&
+                                         match(B, m_Not(m_Specific(CmpRHS)))))
+      return {L.Flavor, SPNB_NA, false};
+  }
+  // b pred d ? m(a, b) : m(a, d) --> m(m(a, b), m(a, d))
+  // ~d pred ~b ? m(a, b) : m(a, d) --> m(m(a, b), m(a, d))
+  if (C == A) {
+    if ((CmpLHS == B && CmpRHS == D) || (match(D, m_Not(m_Specific(CmpLHS))) &&
+                                         match(B, m_Not(m_Specific(CmpRHS)))))
+      return {L.Flavor, SPNB_NA, false};
+  }
+
+  return {SPF_UNKNOWN, SPNB_NA, false};
+}
+
+/// If the input value is the result of a 'not' op, constant integer, or vector
+/// splat of a constant integer, return the bitwise-not source value.
+/// TODO: This could be extended to handle non-splat vector integer constants.
+static Value *getNotValue(Value *V) {
+  Value *NotV;
+  if (match(V, m_Not(m_Value(NotV))))
+    return NotV;
+
+  const APInt *C;
+  if (match(V, m_APInt(C)))
+    return ConstantInt::get(V->getType(), ~(*C));
+
+  return nullptr;
+}
+
+/// Match non-obvious integer minimum and maximum sequences.
+static SelectPatternResult matchMinMax(CmpInst::Predicate Pred,
+                                       Value *CmpLHS, Value *CmpRHS,
+                                       Value *TrueVal, Value *FalseVal,
+                                       Value *&LHS, Value *&RHS,
+                                       unsigned Depth) {
+  // Assume success. If there's no match, callers should not use these anyway.
+  LHS = TrueVal;
+  RHS = FalseVal;
+
+  SelectPatternResult SPR = matchClamp(Pred, CmpLHS, CmpRHS, TrueVal, FalseVal);
+  if (SPR.Flavor != SelectPatternFlavor::SPF_UNKNOWN)
+    return SPR;
+
+  SPR = matchMinMaxOfMinMax(Pred, CmpLHS, CmpRHS, TrueVal, FalseVal, Depth);
+  if (SPR.Flavor != SelectPatternFlavor::SPF_UNKNOWN)
+    return SPR;
+
+  // Look through 'not' ops to find disguised min/max.
+  // (X > Y) ? ~X : ~Y ==> (~X < ~Y) ? ~X : ~Y ==> MIN(~X, ~Y)
+  // (X < Y) ? ~X : ~Y ==> (~X > ~Y) ? ~X : ~Y ==> MAX(~X, ~Y)
+  if (CmpLHS == getNotValue(TrueVal) && CmpRHS == getNotValue(FalseVal)) {
+    switch (Pred) {
+    case CmpInst::ICMP_SGT: return {SPF_SMIN, SPNB_NA, false};
+    case CmpInst::ICMP_SLT: return {SPF_SMAX, SPNB_NA, false};
+    case CmpInst::ICMP_UGT: return {SPF_UMIN, SPNB_NA, false};
+    case CmpInst::ICMP_ULT: return {SPF_UMAX, SPNB_NA, false};
+    default: break;
+    }
+  }
+
+  // (X > Y) ? ~Y : ~X ==> (~X < ~Y) ? ~Y : ~X ==> MAX(~Y, ~X)
+  // (X < Y) ? ~Y : ~X ==> (~X > ~Y) ? ~Y : ~X ==> MIN(~Y, ~X)
+  if (CmpLHS == getNotValue(FalseVal) && CmpRHS == getNotValue(TrueVal)) {
+    switch (Pred) {
+    case CmpInst::ICMP_SGT: return {SPF_SMAX, SPNB_NA, false};
+    case CmpInst::ICMP_SLT: return {SPF_SMIN, SPNB_NA, false};
+    case CmpInst::ICMP_UGT: return {SPF_UMAX, SPNB_NA, false};
+    case CmpInst::ICMP_ULT: return {SPF_UMIN, SPNB_NA, false};
+    default: break;
+    }
+  }
+
+  if (Pred != CmpInst::ICMP_SGT && Pred != CmpInst::ICMP_SLT)
+    return {SPF_UNKNOWN, SPNB_NA, false};
+
+  const APInt *C1;
+  if (!match(CmpRHS, m_APInt(C1)))
+    return {SPF_UNKNOWN, SPNB_NA, false};
+
+  // An unsigned min/max can be written with a signed compare.
+  const APInt *C2;
+  if ((CmpLHS == TrueVal && match(FalseVal, m_APInt(C2))) ||
+      (CmpLHS == FalseVal && match(TrueVal, m_APInt(C2)))) {
+    // Is the sign bit set?
+    // (X <s 0) ? X : MAXVAL ==> (X >u MAXVAL) ? X : MAXVAL ==> UMAX
+    // (X <s 0) ? MAXVAL : X ==> (X >u MAXVAL) ? MAXVAL : X ==> UMIN
+    if (Pred == CmpInst::ICMP_SLT && C1->isZero() && C2->isMaxSignedValue())
+      return {CmpLHS == TrueVal ? SPF_UMAX : SPF_UMIN, SPNB_NA, false};
+
+    // Is the sign bit clear?
+    // (X >s -1) ? MINVAL : X ==> (X <u MINVAL) ? MINVAL : X ==> UMAX
+    // (X >s -1) ? X : MINVAL ==> (X <u MINVAL) ? X : MINVAL ==> UMIN
+    if (Pred == CmpInst::ICMP_SGT && C1->isAllOnes() && C2->isMinSignedValue())
+      return {CmpLHS == FalseVal ? SPF_UMAX : SPF_UMIN, SPNB_NA, false};
+  }
+
+  return {SPF_UNKNOWN, SPNB_NA, false};
+}
+
+bool llvm::isKnownNegation(const Value *X, const Value *Y, bool NeedNSW) {
+  assert(X && Y && "Invalid operand");
+
+  // X = sub (0, Y) || X = sub nsw (0, Y)
+  if ((!NeedNSW && match(X, m_Sub(m_ZeroInt(), m_Specific(Y)))) ||
+      (NeedNSW && match(X, m_NSWSub(m_ZeroInt(), m_Specific(Y)))))
+    return true;
+
+  // Y = sub (0, X) || Y = sub nsw (0, X)
+  if ((!NeedNSW && match(Y, m_Sub(m_ZeroInt(), m_Specific(X)))) ||
+      (NeedNSW && match(Y, m_NSWSub(m_ZeroInt(), m_Specific(X)))))
+    return true;
+
+  // X = sub (A, B), Y = sub (B, A) || X = sub nsw (A, B), Y = sub nsw (B, A)
+  Value *A, *B;
+  return (!NeedNSW && (match(X, m_Sub(m_Value(A), m_Value(B))) &&
+                        match(Y, m_Sub(m_Specific(B), m_Specific(A))))) ||
+         (NeedNSW && (match(X, m_NSWSub(m_Value(A), m_Value(B))) &&
+                       match(Y, m_NSWSub(m_Specific(B), m_Specific(A)))));
+}
+
+static SelectPatternResult matchSelectPattern(CmpInst::Predicate Pred,
+                                              FastMathFlags FMF,
+                                              Value *CmpLHS, Value *CmpRHS,
+                                              Value *TrueVal, Value *FalseVal,
+                                              Value *&LHS, Value *&RHS,
+                                              unsigned Depth) {
+  bool HasMismatchedZeros = false;
+  if (CmpInst::isFPPredicate(Pred)) {
+    // IEEE-754 ignores the sign of 0.0 in comparisons. So if the select has one
+    // 0.0 operand, set the compare's 0.0 operands to that same value for the
+    // purpose of identifying min/max. Disregard vector constants with undefined
+    // elements because those can not be back-propagated for analysis.
+    Value *OutputZeroVal = nullptr;
+    if (match(TrueVal, m_AnyZeroFP()) && !match(FalseVal, m_AnyZeroFP()) &&
+        !cast<Constant>(TrueVal)->containsUndefOrPoisonElement())
+      OutputZeroVal = TrueVal;
+    else if (match(FalseVal, m_AnyZeroFP()) && !match(TrueVal, m_AnyZeroFP()) &&
+             !cast<Constant>(FalseVal)->containsUndefOrPoisonElement())
+      OutputZeroVal = FalseVal;
+
+    if (OutputZeroVal) {
+      if (match(CmpLHS, m_AnyZeroFP()) && CmpLHS != OutputZeroVal) {
+        HasMismatchedZeros = true;
+        CmpLHS = OutputZeroVal;
+      }
+      if (match(CmpRHS, m_AnyZeroFP()) && CmpRHS != OutputZeroVal) {
+        HasMismatchedZeros = true;
+        CmpRHS = OutputZeroVal;
+      }
+    }
+  }
+
+  LHS = CmpLHS;
+  RHS = CmpRHS;
+
+  // Signed zero may return inconsistent results between implementations.
+  //  (0.0 <= -0.0) ? 0.0 : -0.0 // Returns 0.0
+  //  minNum(0.0, -0.0)          // May return -0.0 or 0.0 (IEEE 754-2008 5.3.1)
+  // Therefore, we behave conservatively and only proceed if at least one of the
+  // operands is known to not be zero or if we don't care about signed zero.
+  switch (Pred) {
+  default: break;
+  case CmpInst::FCMP_OGT: case CmpInst::FCMP_OLT:
+  case CmpInst::FCMP_UGT: case CmpInst::FCMP_ULT:
+    if (!HasMismatchedZeros)
+      break;
+    [[fallthrough]];
+  case CmpInst::FCMP_OGE: case CmpInst::FCMP_OLE:
+  case CmpInst::FCMP_UGE: case CmpInst::FCMP_ULE:
+    if (!FMF.noSignedZeros() && !isKnownNonZero(CmpLHS) &&
+        !isKnownNonZero(CmpRHS))
+      return {SPF_UNKNOWN, SPNB_NA, false};
+  }
+
+  SelectPatternNaNBehavior NaNBehavior = SPNB_NA;
+  bool Ordered = false;
+
+  // When given one NaN and one non-NaN input:
+  //   - maxnum/minnum (C99 fmaxf()/fminf()) return the non-NaN input.
+  //   - A simple C99 (a < b ? a : b) construction will return 'b' (as the
+  //     ordered comparison fails), which could be NaN or non-NaN.
+  // so here we discover exactly what NaN behavior is required/accepted.
+  if (CmpInst::isFPPredicate(Pred)) {
+    bool LHSSafe = isKnownNonNaN(CmpLHS, FMF);
+    bool RHSSafe = isKnownNonNaN(CmpRHS, FMF);
+
+    if (LHSSafe && RHSSafe) {
+      // Both operands are known non-NaN.
+      NaNBehavior = SPNB_RETURNS_ANY;
+    } else if (CmpInst::isOrdered(Pred)) {
+      // An ordered comparison will return false when given a NaN, so it
+      // returns the RHS.
+      Ordered = true;
+      if (LHSSafe)
+        // LHS is non-NaN, so if RHS is NaN then NaN will be returned.
+        NaNBehavior = SPNB_RETURNS_NAN;
+      else if (RHSSafe)
+        NaNBehavior = SPNB_RETURNS_OTHER;
+      else
+        // Completely unsafe.
+        return {SPF_UNKNOWN, SPNB_NA, false};
+    } else {
+      Ordered = false;
+      // An unordered comparison will return true when given a NaN, so it
+      // returns the LHS.
+      if (LHSSafe)
+        // LHS is non-NaN, so if RHS is NaN then non-NaN will be returned.
+        NaNBehavior = SPNB_RETURNS_OTHER;
+      else if (RHSSafe)
+        NaNBehavior = SPNB_RETURNS_NAN;
+      else
+        // Completely unsafe.
+        return {SPF_UNKNOWN, SPNB_NA, false};
+    }
+  }
+
+  if (TrueVal == CmpRHS && FalseVal == CmpLHS) {
+    std::swap(CmpLHS, CmpRHS);
+    Pred = CmpInst::getSwappedPredicate(Pred);
+    if (NaNBehavior == SPNB_RETURNS_NAN)
+      NaNBehavior = SPNB_RETURNS_OTHER;
+    else if (NaNBehavior == SPNB_RETURNS_OTHER)
+      NaNBehavior = SPNB_RETURNS_NAN;
+    Ordered = !Ordered;
+  }
+
+  // ([if]cmp X, Y) ? X : Y
+  if (TrueVal == CmpLHS && FalseVal == CmpRHS) {
+    switch (Pred) {
+    default: return {SPF_UNKNOWN, SPNB_NA, false}; // Equality.
+    case ICmpInst::ICMP_UGT:
+    case ICmpInst::ICMP_UGE: return {SPF_UMAX, SPNB_NA, false};
+    case ICmpInst::ICMP_SGT:
+    case ICmpInst::ICMP_SGE: return {SPF_SMAX, SPNB_NA, false};
+    case ICmpInst::ICMP_ULT:
+    case ICmpInst::ICMP_ULE: return {SPF_UMIN, SPNB_NA, false};
+    case ICmpInst::ICMP_SLT:
+    case ICmpInst::ICMP_SLE: return {SPF_SMIN, SPNB_NA, false};
+    case FCmpInst::FCMP_UGT:
+    case FCmpInst::FCMP_UGE:
+    case FCmpInst::FCMP_OGT:
+    case FCmpInst::FCMP_OGE: return {SPF_FMAXNUM, NaNBehavior, Ordered};
+    case FCmpInst::FCMP_ULT:
+    case FCmpInst::FCMP_ULE:
+    case FCmpInst::FCMP_OLT:
+    case FCmpInst::FCMP_OLE: return {SPF_FMINNUM, NaNBehavior, Ordered};
+    }
+  }
+
+  if (isKnownNegation(TrueVal, FalseVal)) {
+    // Sign-extending LHS does not change its sign, so TrueVal/FalseVal can
+    // match against either LHS or sext(LHS).
+    auto MaybeSExtCmpLHS =
+        m_CombineOr(m_Specific(CmpLHS), m_SExt(m_Specific(CmpLHS)));
+    auto ZeroOrAllOnes = m_CombineOr(m_ZeroInt(), m_AllOnes());
+    auto ZeroOrOne = m_CombineOr(m_ZeroInt(), m_One());
+    if (match(TrueVal, MaybeSExtCmpLHS)) {
+      // Set the return values. If the compare uses the negated value (-X >s 0),
+      // swap the return values because the negated value is always 'RHS'.
+      LHS = TrueVal;
+      RHS = FalseVal;
+      if (match(CmpLHS, m_Neg(m_Specific(FalseVal))))
+        std::swap(LHS, RHS);
+
+      // (X >s 0) ? X : -X or (X >s -1) ? X : -X --> ABS(X)
+      // (-X >s 0) ? -X : X or (-X >s -1) ? -X : X --> ABS(X)
+      if (Pred == ICmpInst::ICMP_SGT && match(CmpRHS, ZeroOrAllOnes))
+        return {SPF_ABS, SPNB_NA, false};
+
+      // (X >=s 0) ? X : -X or (X >=s 1) ? X : -X --> ABS(X)
+      if (Pred == ICmpInst::ICMP_SGE && match(CmpRHS, ZeroOrOne))
+        return {SPF_ABS, SPNB_NA, false};
+
+      // (X <s 0) ? X : -X or (X <s 1) ? X : -X --> NABS(X)
+      // (-X <s 0) ? -X : X or (-X <s 1) ? -X : X --> NABS(X)
+      if (Pred == ICmpInst::ICMP_SLT && match(CmpRHS, ZeroOrOne))
+        return {SPF_NABS, SPNB_NA, false};
+    }
+    else if (match(FalseVal, MaybeSExtCmpLHS)) {
+      // Set the return values. If the compare uses the negated value (-X >s 0),
+      // swap the return values because the negated value is always 'RHS'.
+      LHS = FalseVal;
+      RHS = TrueVal;
+      if (match(CmpLHS, m_Neg(m_Specific(TrueVal))))
+        std::swap(LHS, RHS);
+
+      // (X >s 0) ? -X : X or (X >s -1) ? -X : X --> NABS(X)
+      // (-X >s 0) ? X : -X or (-X >s -1) ? X : -X --> NABS(X)
+      if (Pred == ICmpInst::ICMP_SGT && match(CmpRHS, ZeroOrAllOnes))
+        return {SPF_NABS, SPNB_NA, false};
+
+      // (X <s 0) ? -X : X or (X <s 1) ? -X : X --> ABS(X)
+      // (-X <s 0) ? X : -X or (-X <s 1) ? X : -X --> ABS(X)
+      if (Pred == ICmpInst::ICMP_SLT && match(CmpRHS, ZeroOrOne))
+        return {SPF_ABS, SPNB_NA, false};
+    }
+  }
+
+  if (CmpInst::isIntPredicate(Pred))
+    return matchMinMax(Pred, CmpLHS, CmpRHS, TrueVal, FalseVal, LHS, RHS, Depth);
+
+  // According to (IEEE 754-2008 5.3.1), minNum(0.0, -0.0) and similar
+  // may return either -0.0 or 0.0, so fcmp/select pair has stricter
+  // semantics than minNum. Be conservative in such case.
+  if (NaNBehavior != SPNB_RETURNS_ANY ||
+      (!FMF.noSignedZeros() && !isKnownNonZero(CmpLHS) &&
+       !isKnownNonZero(CmpRHS)))
+    return {SPF_UNKNOWN, SPNB_NA, false};
+
+  return matchFastFloatClamp(Pred, CmpLHS, CmpRHS, TrueVal, FalseVal, LHS, RHS);
+}
+
+/// Helps to match a select pattern in case of a type mismatch.
+///
+/// The function processes the case when type of true and false values of a
+/// select instruction differs from type of the cmp instruction operands because
+/// of a cast instruction. The function checks if it is legal to move the cast
+/// operation after "select". If yes, it returns the new second value of
+/// "select" (with the assumption that cast is moved):
+/// 1. As operand of cast instruction when both values of "select" are same cast
+/// instructions.
+/// 2. As restored constant (by applying reverse cast operation) when the first
+/// value of the "select" is a cast operation and the second value is a
+/// constant.
+/// NOTE: We return only the new second value because the first value could be
+/// accessed as operand of cast instruction.
+static Value *lookThroughCast(CmpInst *CmpI, Value *V1, Value *V2,
+                              Instruction::CastOps *CastOp) {
+  auto *Cast1 = dyn_cast<CastInst>(V1);
+  if (!Cast1)
+    return nullptr;
+
+  *CastOp = Cast1->getOpcode();
+  Type *SrcTy = Cast1->getSrcTy();
+  if (auto *Cast2 = dyn_cast<CastInst>(V2)) {
+    // If V1 and V2 are both the same cast from the same type, look through V1.
+    if (*CastOp == Cast2->getOpcode() && SrcTy == Cast2->getSrcTy())
+      return Cast2->getOperand(0);
+    return nullptr;
+  }
+
+  auto *C = dyn_cast<Constant>(V2);
+  if (!C)
+    return nullptr;
+
+  Constant *CastedTo = nullptr;
+  switch (*CastOp) {
+  case Instruction::ZExt:
+    if (CmpI->isUnsigned())
+      CastedTo = ConstantExpr::getTrunc(C, SrcTy);
+    break;
+  case Instruction::SExt:
+    if (CmpI->isSigned())
+      CastedTo = ConstantExpr::getTrunc(C, SrcTy, true);
+    break;
+  case Instruction::Trunc:
+    Constant *CmpConst;
+    if (match(CmpI->getOperand(1), m_Constant(CmpConst)) &&
+        CmpConst->getType() == SrcTy) {
+      // Here we have the following case:
+      //
+      //   %cond = cmp iN %x, CmpConst
+      //   %tr = trunc iN %x to iK
+      //   %narrowsel = select i1 %cond, iK %t, iK C
+      //
+      // We can always move trunc after select operation:
+      //
+      //   %cond = cmp iN %x, CmpConst
+      //   %widesel = select i1 %cond, iN %x, iN CmpConst
+      //   %tr = trunc iN %widesel to iK
+      //
+      // Note that C could be extended in any way because we don't care about
+      // upper bits after truncation. It can't be abs pattern, because it would
+      // look like:
+      //
+      //   select i1 %cond, x, -x.
+      //
+      // So only min/max pattern could be matched. Such match requires widened C
+      // == CmpConst. That is why set widened C = CmpConst, condition trunc
+      // CmpConst == C is checked below.
+      CastedTo = CmpConst;
+    } else {
+      CastedTo = ConstantExpr::getIntegerCast(C, SrcTy, CmpI->isSigned());
+    }
+    break;
+  case Instruction::FPTrunc:
+    CastedTo = ConstantExpr::getFPExtend(C, SrcTy, true);
+    break;
+  case Instruction::FPExt:
+    CastedTo = ConstantExpr::getFPTrunc(C, SrcTy, true);
+    break;
+  case Instruction::FPToUI:
+    CastedTo = ConstantExpr::getUIToFP(C, SrcTy, true);
+    break;
+  case Instruction::FPToSI:
+    CastedTo = ConstantExpr::getSIToFP(C, SrcTy, true);
+    break;
+  case Instruction::UIToFP:
+    CastedTo = ConstantExpr::getFPToUI(C, SrcTy, true);
+    break;
+  case Instruction::SIToFP:
+    CastedTo = ConstantExpr::getFPToSI(C, SrcTy, true);
+    break;
+  default:
+    break;
+  }
+
+  if (!CastedTo)
+    return nullptr;
+
+  // Make sure the cast doesn't lose any information.
+  Constant *CastedBack =
+      ConstantExpr::getCast(*CastOp, CastedTo, C->getType(), true);
+  if (CastedBack != C)
+    return nullptr;
+
+  return CastedTo;
+}
+
+SelectPatternResult llvm::matchSelectPattern(Value *V, Value *&LHS, Value *&RHS,
+                                             Instruction::CastOps *CastOp,
+                                             unsigned Depth) {
+  if (Depth >= MaxAnalysisRecursionDepth)
+    return {SPF_UNKNOWN, SPNB_NA, false};
+
+  SelectInst *SI = dyn_cast<SelectInst>(V);
+  if (!SI) return {SPF_UNKNOWN, SPNB_NA, false};
+
+  CmpInst *CmpI = dyn_cast<CmpInst>(SI->getCondition());
+  if (!CmpI) return {SPF_UNKNOWN, SPNB_NA, false};
+
+  Value *TrueVal = SI->getTrueValue();
+  Value *FalseVal = SI->getFalseValue();
+
+  return llvm::matchDecomposedSelectPattern(CmpI, TrueVal, FalseVal, LHS, RHS,
+                                            CastOp, Depth);
+}
+
+SelectPatternResult llvm::matchDecomposedSelectPattern(
+    CmpInst *CmpI, Value *TrueVal, Value *FalseVal, Value *&LHS, Value *&RHS,
+    Instruction::CastOps *CastOp, unsigned Depth) {
+  CmpInst::Predicate Pred = CmpI->getPredicate();
+  Value *CmpLHS = CmpI->getOperand(0);
+  Value *CmpRHS = CmpI->getOperand(1);
+  FastMathFlags FMF;
+  if (isa<FPMathOperator>(CmpI))
+    FMF = CmpI->getFastMathFlags();
+
+  // Bail out early.
+  if (CmpI->isEquality())
+    return {SPF_UNKNOWN, SPNB_NA, false};
+
+  // Deal with type mismatches.
+  if (CastOp && CmpLHS->getType() != TrueVal->getType()) {
+    if (Value *C = lookThroughCast(CmpI, TrueVal, FalseVal, CastOp)) {
+      // If this is a potential fmin/fmax with a cast to integer, then ignore
+      // -0.0 because there is no corresponding integer value.
+      if (*CastOp == Instruction::FPToSI || *CastOp == Instruction::FPToUI)
+        FMF.setNoSignedZeros();
+      return ::matchSelectPattern(Pred, FMF, CmpLHS, CmpRHS,
+                                  cast<CastInst>(TrueVal)->getOperand(0), C,
+                                  LHS, RHS, Depth);
+    }
+    if (Value *C = lookThroughCast(CmpI, FalseVal, TrueVal, CastOp)) {
+      // If this is a potential fmin/fmax with a cast to integer, then ignore
+      // -0.0 because there is no corresponding integer value.
+      if (*CastOp == Instruction::FPToSI || *CastOp == Instruction::FPToUI)
+        FMF.setNoSignedZeros();
+      return ::matchSelectPattern(Pred, FMF, CmpLHS, CmpRHS,
+                                  C, cast<CastInst>(FalseVal)->getOperand(0),
+                                  LHS, RHS, Depth);
+    }
+  }
+  return ::matchSelectPattern(Pred, FMF, CmpLHS, CmpRHS, TrueVal, FalseVal,
+                              LHS, RHS, Depth);
+}
+
+CmpInst::Predicate llvm::getMinMaxPred(SelectPatternFlavor SPF, bool Ordered) {
+  if (SPF == SPF_SMIN) return ICmpInst::ICMP_SLT;
+  if (SPF == SPF_UMIN) return ICmpInst::ICMP_ULT;
+  if (SPF == SPF_SMAX) return ICmpInst::ICMP_SGT;
+  if (SPF == SPF_UMAX) return ICmpInst::ICMP_UGT;
+  if (SPF == SPF_FMINNUM)
+    return Ordered ? FCmpInst::FCMP_OLT : FCmpInst::FCMP_ULT;
+  if (SPF == SPF_FMAXNUM)
+    return Ordered ? FCmpInst::FCMP_OGT : FCmpInst::FCMP_UGT;
+  llvm_unreachable("unhandled!");
+}
+
+SelectPatternFlavor llvm::getInverseMinMaxFlavor(SelectPatternFlavor SPF) {
+  if (SPF == SPF_SMIN) return SPF_SMAX;
+  if (SPF == SPF_UMIN) return SPF_UMAX;
+  if (SPF == SPF_SMAX) return SPF_SMIN;
+  if (SPF == SPF_UMAX) return SPF_UMIN;
+  llvm_unreachable("unhandled!");
+}
+
+Intrinsic::ID llvm::getInverseMinMaxIntrinsic(Intrinsic::ID MinMaxID) {
+  switch (MinMaxID) {
+  case Intrinsic::smax: return Intrinsic::smin;
+  case Intrinsic::smin: return Intrinsic::smax;
+  case Intrinsic::umax: return Intrinsic::umin;
+  case Intrinsic::umin: return Intrinsic::umax;
+  default: llvm_unreachable("Unexpected intrinsic");
+  }
+}
+
+APInt llvm::getMinMaxLimit(SelectPatternFlavor SPF, unsigned BitWidth) {
+  switch (SPF) {
+  case SPF_SMAX: return APInt::getSignedMaxValue(BitWidth);
+  case SPF_SMIN: return APInt::getSignedMinValue(BitWidth);
+  case SPF_UMAX: return APInt::getMaxValue(BitWidth);
+  case SPF_UMIN: return APInt::getMinValue(BitWidth);
+  default: llvm_unreachable("Unexpected flavor");
+  }
+}
+
+std::pair<Intrinsic::ID, bool>
+llvm::canConvertToMinOrMaxIntrinsic(ArrayRef<Value *> VL) {
+  // Check if VL contains select instructions that can be folded into a min/max
+  // vector intrinsic and return the intrinsic if it is possible.
+  // TODO: Support floating point min/max.
+  bool AllCmpSingleUse = true;
+  SelectPatternResult SelectPattern;
+  SelectPattern.Flavor = SPF_UNKNOWN;
+  if (all_of(VL, [&SelectPattern, &AllCmpSingleUse](Value *I) {
+        Value *LHS, *RHS;
+        auto CurrentPattern = matchSelectPattern(I, LHS, RHS);
+        if (!SelectPatternResult::isMinOrMax(CurrentPattern.Flavor) ||
+            CurrentPattern.Flavor == SPF_FMINNUM ||
+            CurrentPattern.Flavor == SPF_FMAXNUM ||
+            !I->getType()->isIntOrIntVectorTy())
+          return false;
+        if (SelectPattern.Flavor != SPF_UNKNOWN &&
+            SelectPattern.Flavor != CurrentPattern.Flavor)
+          return false;
+        SelectPattern = CurrentPattern;
+        AllCmpSingleUse &=
+            match(I, m_Select(m_OneUse(m_Value()), m_Value(), m_Value()));
+        return true;
+      })) {
+    switch (SelectPattern.Flavor) {
+    case SPF_SMIN:
+      return {Intrinsic::smin, AllCmpSingleUse};
+    case SPF_UMIN:
+      return {Intrinsic::umin, AllCmpSingleUse};
+    case SPF_SMAX:
+      return {Intrinsic::smax, AllCmpSingleUse};
+    case SPF_UMAX:
+      return {Intrinsic::umax, AllCmpSingleUse};
+    default:
+      llvm_unreachable("unexpected select pattern flavor");
+    }
+  }
+  return {Intrinsic::not_intrinsic, false};
+}
+
+bool llvm::matchSimpleRecurrence(const PHINode *P, BinaryOperator *&BO,
+                                 Value *&Start, Value *&Step) {
+  // Handle the case of a simple two-predecessor recurrence PHI.
+  // There's a lot more that could theoretically be done here, but
+  // this is sufficient to catch some interesting cases.
+  if (P->getNumIncomingValues() != 2)
+    return false;
+
+  for (unsigned i = 0; i != 2; ++i) {
+    Value *L = P->getIncomingValue(i);
+    Value *R = P->getIncomingValue(!i);
+    Operator *LU = dyn_cast<Operator>(L);
+    if (!LU)
+      continue;
+    unsigned Opcode = LU->getOpcode();
+
+    switch (Opcode) {
+    default:
+      continue;
+    // TODO: Expand list -- xor, div, gep, uaddo, etc..
+    case Instruction::LShr:
+    case Instruction::AShr:
+    case Instruction::Shl:
+    case Instruction::Add:
+    case Instruction::Sub:
+    case Instruction::And:
+    case Instruction::Or:
+    case Instruction::Mul:
+    case Instruction::FMul: {
+      Value *LL = LU->getOperand(0);
+      Value *LR = LU->getOperand(1);
+      // Find a recurrence.
+      if (LL == P)
+        L = LR;
+      else if (LR == P)
+        L = LL;
+      else
+        continue; // Check for recurrence with L and R flipped.
+
+      break; // Match!
+    }
+    };
+
+    // We have matched a recurrence of the form:
+    //   %iv = [R, %entry], [%iv.next, %backedge]
+    //   %iv.next = binop %iv, L
+    // OR
+    //   %iv = [R, %entry], [%iv.next, %backedge]
+    //   %iv.next = binop L, %iv
+    BO = cast<BinaryOperator>(LU);
+    Start = R;
+    Step = L;
+    return true;
+  }
+  return false;
+}
+
+bool llvm::matchSimpleRecurrence(const BinaryOperator *I, PHINode *&P,
+                                 Value *&Start, Value *&Step) {
+  BinaryOperator *BO = nullptr;
+  P = dyn_cast<PHINode>(I->getOperand(0));
+  if (!P)
+    P = dyn_cast<PHINode>(I->getOperand(1));
+  return P && matchSimpleRecurrence(P, BO, Start, Step) && BO == I;
+}
+
+/// Return true if "icmp Pred LHS RHS" is always true.
+static bool isTruePredicate(CmpInst::Predicate Pred, const Value *LHS,
+                            const Value *RHS, const DataLayout &DL,
+                            unsigned Depth) {
+  if (ICmpInst::isTrueWhenEqual(Pred) && LHS == RHS)
+    return true;
+
+  switch (Pred) {
+  default:
+    return false;
+
+  case CmpInst::ICMP_SLE: {
+    const APInt *C;
+
+    // LHS s<= LHS +_{nsw} C   if C >= 0
+    if (match(RHS, m_NSWAdd(m_Specific(LHS), m_APInt(C))))
+      return !C->isNegative();
+    return false;
+  }
+
+  case CmpInst::ICMP_ULE: {
+    const APInt *C;
+
+    // LHS u<= LHS +_{nuw} C   for any C
+    if (match(RHS, m_NUWAdd(m_Specific(LHS), m_APInt(C))))
+      return true;
+
+    // Match A to (X +_{nuw} CA) and B to (X +_{nuw} CB)
+    auto MatchNUWAddsToSameValue = [&](const Value *A, const Value *B,
+                                       const Value *&X,
+                                       const APInt *&CA, const APInt *&CB) {
+      if (match(A, m_NUWAdd(m_Value(X), m_APInt(CA))) &&
+          match(B, m_NUWAdd(m_Specific(X), m_APInt(CB))))
+        return true;
+
+      // If X & C == 0 then (X | C) == X +_{nuw} C
+      if (match(A, m_Or(m_Value(X), m_APInt(CA))) &&
+          match(B, m_Or(m_Specific(X), m_APInt(CB)))) {
+        KnownBits Known(CA->getBitWidth());
+        computeKnownBits(X, Known, DL, Depth + 1, /*AC*/ nullptr,
+                         /*CxtI*/ nullptr, /*DT*/ nullptr);
+        if (CA->isSubsetOf(Known.Zero) && CB->isSubsetOf(Known.Zero))
+          return true;
+      }
+
+      return false;
+    };
+
+    const Value *X;
+    const APInt *CLHS, *CRHS;
+    if (MatchNUWAddsToSameValue(LHS, RHS, X, CLHS, CRHS))
+      return CLHS->ule(*CRHS);
+
+    return false;
+  }
+  }
+}
+
+/// Return true if "icmp Pred BLHS BRHS" is true whenever "icmp Pred
+/// ALHS ARHS" is true.  Otherwise, return std::nullopt.
+static std::optional<bool>
+isImpliedCondOperands(CmpInst::Predicate Pred, const Value *ALHS,
+                      const Value *ARHS, const Value *BLHS, const Value *BRHS,
+                      const DataLayout &DL, unsigned Depth) {
+  switch (Pred) {
+  default:
+    return std::nullopt;
+
+  case CmpInst::ICMP_SLT:
+  case CmpInst::ICMP_SLE:
+    if (isTruePredicate(CmpInst::ICMP_SLE, BLHS, ALHS, DL, Depth) &&
+        isTruePredicate(CmpInst::ICMP_SLE, ARHS, BRHS, DL, Depth))
+      return true;
+    return std::nullopt;
+
+  case CmpInst::ICMP_ULT:
+  case CmpInst::ICMP_ULE:
+    if (isTruePredicate(CmpInst::ICMP_ULE, BLHS, ALHS, DL, Depth) &&
+        isTruePredicate(CmpInst::ICMP_ULE, ARHS, BRHS, DL, Depth))
+      return true;
+    return std::nullopt;
+  }
+}
+
+/// Return true if the operands of two compares (expanded as "L0 pred L1" and
+/// "R0 pred R1") match. IsSwappedOps is true when the operands match, but are
+/// swapped.
+static bool areMatchingOperands(const Value *L0, const Value *L1, const Value *R0,
+                           const Value *R1, bool &AreSwappedOps) {
+  bool AreMatchingOps = (L0 == R0 && L1 == R1);
+  AreSwappedOps = (L0 == R1 && L1 == R0);
+  return AreMatchingOps || AreSwappedOps;
+}
+
+/// Return true if "icmp1 LPred X, Y" implies "icmp2 RPred X, Y" is true.
+/// Return false if "icmp1 LPred X, Y" implies "icmp2 RPred X, Y" is false.
+/// Otherwise, return std::nullopt if we can't infer anything.
+static std::optional<bool>
+isImpliedCondMatchingOperands(CmpInst::Predicate LPred,
+                              CmpInst::Predicate RPred, bool AreSwappedOps) {
+  // Canonicalize the predicate as if the operands were not commuted.
+  if (AreSwappedOps)
+    RPred = ICmpInst::getSwappedPredicate(RPred);
+
+  if (CmpInst::isImpliedTrueByMatchingCmp(LPred, RPred))
+    return true;
+  if (CmpInst::isImpliedFalseByMatchingCmp(LPred, RPred))
+    return false;
+
+  return std::nullopt;
+}
+
+/// Return true if "icmp LPred X, LC" implies "icmp RPred X, RC" is true.
+/// Return false if "icmp LPred X, LC" implies "icmp RPred X, RC" is false.
+/// Otherwise, return std::nullopt if we can't infer anything.
+static std::optional<bool> isImpliedCondCommonOperandWithConstants(
+    CmpInst::Predicate LPred, const APInt &LC, CmpInst::Predicate RPred,
+    const APInt &RC) {
+  ConstantRange DomCR = ConstantRange::makeExactICmpRegion(LPred, LC);
+  ConstantRange CR = ConstantRange::makeExactICmpRegion(RPred, RC);
+  ConstantRange Intersection = DomCR.intersectWith(CR);
+  ConstantRange Difference = DomCR.difference(CR);
+  if (Intersection.isEmptySet())
+    return false;
+  if (Difference.isEmptySet())
+    return true;
+  return std::nullopt;
+}
+
+/// Return true if LHS implies RHS (expanded to its components as "R0 RPred R1")
+/// is true.  Return false if LHS implies RHS is false. Otherwise, return
+/// std::nullopt if we can't infer anything.
+static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
+                                              CmpInst::Predicate RPred,
+                                              const Value *R0, const Value *R1,
+                                              const DataLayout &DL,
+                                              bool LHSIsTrue, unsigned Depth) {
+  Value *L0 = LHS->getOperand(0);
+  Value *L1 = LHS->getOperand(1);
+
+  // The rest of the logic assumes the LHS condition is true.  If that's not the
+  // case, invert the predicate to make it so.
+  CmpInst::Predicate LPred =
+      LHSIsTrue ? LHS->getPredicate() : LHS->getInversePredicate();
+
+  // Can we infer anything when the two compares have matching operands?
+  bool AreSwappedOps;
+  if (areMatchingOperands(L0, L1, R0, R1, AreSwappedOps))
+    return isImpliedCondMatchingOperands(LPred, RPred, AreSwappedOps);
+
+  // Can we infer anything when the 0-operands match and the 1-operands are
+  // constants (not necessarily matching)?
+  const APInt *LC, *RC;
+  if (L0 == R0 && match(L1, m_APInt(LC)) && match(R1, m_APInt(RC)))
+    return isImpliedCondCommonOperandWithConstants(LPred, *LC, RPred, *RC);
+
+  if (LPred == RPred)
+    return isImpliedCondOperands(LPred, L0, L1, R0, R1, DL, Depth);
+
+  return std::nullopt;
+}
+
+/// Return true if LHS implies RHS is true.  Return false if LHS implies RHS is
+/// false.  Otherwise, return std::nullopt if we can't infer anything.  We
+/// expect the RHS to be an icmp and the LHS to be an 'and', 'or', or a 'select'
+/// instruction.
+static std::optional<bool>
+isImpliedCondAndOr(const Instruction *LHS, CmpInst::Predicate RHSPred,
+                   const Value *RHSOp0, const Value *RHSOp1,
+                   const DataLayout &DL, bool LHSIsTrue, unsigned Depth) {
+  // The LHS must be an 'or', 'and', or a 'select' instruction.
+  assert((LHS->getOpcode() == Instruction::And ||
+          LHS->getOpcode() == Instruction::Or ||
+          LHS->getOpcode() == Instruction::Select) &&
+         "Expected LHS to be 'and', 'or', or 'select'.");
+
+  assert(Depth <= MaxAnalysisRecursionDepth && "Hit recursion limit");
+
+  // If the result of an 'or' is false, then we know both legs of the 'or' are
+  // false.  Similarly, if the result of an 'and' is true, then we know both
+  // legs of the 'and' are true.
+  const Value *ALHS, *ARHS;
+  if ((!LHSIsTrue && match(LHS, m_LogicalOr(m_Value(ALHS), m_Value(ARHS)))) ||
+      (LHSIsTrue && match(LHS, m_LogicalAnd(m_Value(ALHS), m_Value(ARHS))))) {
+    // FIXME: Make this non-recursion.
+    if (std::optional<bool> Implication = isImpliedCondition(
+            ALHS, RHSPred, RHSOp0, RHSOp1, DL, LHSIsTrue, Depth + 1))
+      return Implication;
+    if (std::optional<bool> Implication = isImpliedCondition(
+            ARHS, RHSPred, RHSOp0, RHSOp1, DL, LHSIsTrue, Depth + 1))
+      return Implication;
+    return std::nullopt;
+  }
+  return std::nullopt;
+}
+
+std::optional<bool>
+llvm::isImpliedCondition(const Value *LHS, CmpInst::Predicate RHSPred,
+                         const Value *RHSOp0, const Value *RHSOp1,
+                         const DataLayout &DL, bool LHSIsTrue, unsigned Depth) {
+  // Bail out when we hit the limit.
+  if (Depth == MaxAnalysisRecursionDepth)
+    return std::nullopt;
+
+  // A mismatch occurs when we compare a scalar cmp to a vector cmp, for
+  // example.
+  if (RHSOp0->getType()->isVectorTy() != LHS->getType()->isVectorTy())
+    return std::nullopt;
+
+  assert(LHS->getType()->isIntOrIntVectorTy(1) &&
+         "Expected integer type only!");
+
+  // Both LHS and RHS are icmps.
+  const ICmpInst *LHSCmp = dyn_cast<ICmpInst>(LHS);
+  if (LHSCmp)
+    return isImpliedCondICmps(LHSCmp, RHSPred, RHSOp0, RHSOp1, DL, LHSIsTrue,
+                              Depth);
+
+  /// The LHS should be an 'or', 'and', or a 'select' instruction.  We expect
+  /// the RHS to be an icmp.
+  /// FIXME: Add support for and/or/select on the RHS.
+  if (const Instruction *LHSI = dyn_cast<Instruction>(LHS)) {
+    if ((LHSI->getOpcode() == Instruction::And ||
+         LHSI->getOpcode() == Instruction::Or ||
+         LHSI->getOpcode() == Instruction::Select))
+      return isImpliedCondAndOr(LHSI, RHSPred, RHSOp0, RHSOp1, DL, LHSIsTrue,
+                                Depth);
+  }
+  return std::nullopt;
+}
+
+std::optional<bool> llvm::isImpliedCondition(const Value *LHS, const Value *RHS,
+                                             const DataLayout &DL,
+                                             bool LHSIsTrue, unsigned Depth) {
+  // LHS ==> RHS by definition
+  if (LHS == RHS)
+    return LHSIsTrue;
+
+  if (const ICmpInst *RHSCmp = dyn_cast<ICmpInst>(RHS))
+    return isImpliedCondition(LHS, RHSCmp->getPredicate(),
+                              RHSCmp->getOperand(0), RHSCmp->getOperand(1), DL,
+                              LHSIsTrue, Depth);
+
+  if (Depth == MaxAnalysisRecursionDepth)
+    return std::nullopt;
+
+  // LHS ==> (RHS1 || RHS2) if LHS ==> RHS1 or LHS ==> RHS2
+  // LHS ==> !(RHS1 && RHS2) if LHS ==> !RHS1 or LHS ==> !RHS2
+  const Value *RHS1, *RHS2;
+  if (match(RHS, m_LogicalOr(m_Value(RHS1), m_Value(RHS2)))) {
+    if (std::optional<bool> Imp =
+            isImpliedCondition(LHS, RHS1, DL, LHSIsTrue, Depth + 1))
+      if (*Imp == true)
+        return true;
+    if (std::optional<bool> Imp =
+            isImpliedCondition(LHS, RHS2, DL, LHSIsTrue, Depth + 1))
+      if (*Imp == true)
+        return true;
+  }
+  if (match(RHS, m_LogicalAnd(m_Value(RHS1), m_Value(RHS2)))) {
+    if (std::optional<bool> Imp =
+            isImpliedCondition(LHS, RHS1, DL, LHSIsTrue, Depth + 1))
+      if (*Imp == false)
+        return false;
+    if (std::optional<bool> Imp =
+            isImpliedCondition(LHS, RHS2, DL, LHSIsTrue, Depth + 1))
+      if (*Imp == false)
+        return false;
+  }
+
+  return std::nullopt;
+}
+
+// Returns a pair (Condition, ConditionIsTrue), where Condition is a branch
+// condition dominating ContextI or nullptr, if no condition is found.
+static std::pair<Value *, bool>
+getDomPredecessorCondition(const Instruction *ContextI) {
+  if (!ContextI || !ContextI->getParent())
+    return {nullptr, false};
+
+  // TODO: This is a poor/cheap way to determine dominance. Should we use a
+  // dominator tree (eg, from a SimplifyQuery) instead?
+  const BasicBlock *ContextBB = ContextI->getParent();
+  const BasicBlock *PredBB = ContextBB->getSinglePredecessor();
+  if (!PredBB)
+    return {nullptr, false};
+
+  // We need a conditional branch in the predecessor.
+  Value *PredCond;
+  BasicBlock *TrueBB, *FalseBB;
+  if (!match(PredBB->getTerminator(), m_Br(m_Value(PredCond), TrueBB, FalseBB)))
+    return {nullptr, false};
+
+  // The branch should get simplified. Don't bother simplifying this condition.
+  if (TrueBB == FalseBB)
+    return {nullptr, false};
+
+  assert((TrueBB == ContextBB || FalseBB == ContextBB) &&
+         "Predecessor block does not point to successor?");
+
+  // Is this condition implied by the predecessor condition?
+  return {PredCond, TrueBB == ContextBB};
+}
+
+std::optional<bool> llvm::isImpliedByDomCondition(const Value *Cond,
+                                                  const Instruction *ContextI,
+                                                  const DataLayout &DL) {
+  assert(Cond->getType()->isIntOrIntVectorTy(1) && "Condition must be bool");
+  auto PredCond = getDomPredecessorCondition(ContextI);
+  if (PredCond.first)
+    return isImpliedCondition(PredCond.first, Cond, DL, PredCond.second);
+  return std::nullopt;
+}
+
+std::optional<bool> llvm::isImpliedByDomCondition(CmpInst::Predicate Pred,
+                                                  const Value *LHS,
+                                                  const Value *RHS,
+                                                  const Instruction *ContextI,
+                                                  const DataLayout &DL) {
+  auto PredCond = getDomPredecessorCondition(ContextI);
+  if (PredCond.first)
+    return isImpliedCondition(PredCond.first, Pred, LHS, RHS, DL,
+                              PredCond.second);
+  return std::nullopt;
+}
+
+static void setLimitsForBinOp(const BinaryOperator &BO, APInt &Lower,
+                              APInt &Upper, const InstrInfoQuery &IIQ,
+                              bool PreferSignedRange) {
+  unsigned Width = Lower.getBitWidth();
+  const APInt *C;
+  switch (BO.getOpcode()) {
+  case Instruction::Add:
+    if (match(BO.getOperand(1), m_APInt(C)) && !C->isZero()) {
+      bool HasNSW = IIQ.hasNoSignedWrap(&BO);
+      bool HasNUW = IIQ.hasNoUnsignedWrap(&BO);
+
+      // If the caller expects a signed compare, then try to use a signed range.
+      // Otherwise if both no-wraps are set, use the unsigned range because it
+      // is never larger than the signed range. Example:
+      // "add nuw nsw i8 X, -2" is unsigned [254,255] vs. signed [-128, 125].
+      if (PreferSignedRange && HasNSW && HasNUW)
+        HasNUW = false;
+
+      if (HasNUW) {
+        // 'add nuw x, C' produces [C, UINT_MAX].
+        Lower = *C;
+      } else if (HasNSW) {
+        if (C->isNegative()) {
+          // 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
+          Lower = APInt::getSignedMinValue(Width);
+          Upper = APInt::getSignedMaxValue(Width) + *C + 1;
+        } else {
+          // 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
+          Lower = APInt::getSignedMinValue(Width) + *C;
+          Upper = APInt::getSignedMaxValue(Width) + 1;
+        }
+      }
+    }
+    break;
+
+  case Instruction::And:
+    if (match(BO.getOperand(1), m_APInt(C)))
+      // 'and x, C' produces [0, C].
+      Upper = *C + 1;
+    break;
+
+  case Instruction::Or:
+    if (match(BO.getOperand(1), m_APInt(C)))
+      // 'or x, C' produces [C, UINT_MAX].
+      Lower = *C;
+    break;
+
+  case Instruction::AShr:
+    if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
+      // 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
+      Lower = APInt::getSignedMinValue(Width).ashr(*C);
+      Upper = APInt::getSignedMaxValue(Width).ashr(*C) + 1;
+    } else if (match(BO.getOperand(0), m_APInt(C))) {
+      unsigned ShiftAmount = Width - 1;
+      if (!C->isZero() && IIQ.isExact(&BO))
+        ShiftAmount = C->countTrailingZeros();
+      if (C->isNegative()) {
+        // 'ashr C, x' produces [C, C >> (Width-1)]
+        Lower = *C;
+        Upper = C->ashr(ShiftAmount) + 1;
+      } else {
+        // 'ashr C, x' produces [C >> (Width-1), C]
+        Lower = C->ashr(ShiftAmount);
+        Upper = *C + 1;
+      }
+    }
+    break;
+
+  case Instruction::LShr:
+    if (match(BO.getOperand(1), m_APInt(C)) && C->ult(Width)) {
+      // 'lshr x, C' produces [0, UINT_MAX >> C].
+      Upper = APInt::getAllOnes(Width).lshr(*C) + 1;
+    } else if (match(BO.getOperand(0), m_APInt(C))) {
+      // 'lshr C, x' produces [C >> (Width-1), C].
+      unsigned ShiftAmount = Width - 1;
+      if (!C->isZero() && IIQ.isExact(&BO))
+        ShiftAmount = C->countTrailingZeros();
+      Lower = C->lshr(ShiftAmount);
+      Upper = *C + 1;
+    }
+    break;
+
+  case Instruction::Shl:
+    if (match(BO.getOperand(0), m_APInt(C))) {
+      if (IIQ.hasNoUnsignedWrap(&BO)) {
+        // 'shl nuw C, x' produces [C, C << CLZ(C)]
+        Lower = *C;
+        Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
+      } else if (BO.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
+        if (C->isNegative()) {
+          // 'shl nsw C, x' produces [C << CLO(C)-1, C]
+          unsigned ShiftAmount = C->countLeadingOnes() - 1;
+          Lower = C->shl(ShiftAmount);
+          Upper = *C + 1;
+        } else {
+          // 'shl nsw C, x' produces [C, C << CLZ(C)-1]
+          unsigned ShiftAmount = C->countLeadingZeros() - 1;
+          Lower = *C;
+          Upper = C->shl(ShiftAmount) + 1;
+        }
+      }
+    }
+    break;
+
+  case Instruction::SDiv:
+    if (match(BO.getOperand(1), m_APInt(C))) {
+      APInt IntMin = APInt::getSignedMinValue(Width);
+      APInt IntMax = APInt::getSignedMaxValue(Width);
+      if (C->isAllOnes()) {
+        // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
+        //    where C != -1 and C != 0 and C != 1
+        Lower = IntMin + 1;
+        Upper = IntMax + 1;
+      } else if (C->countLeadingZeros() < Width - 1) {
+        // 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
+        //    where C != -1 and C != 0 and C != 1
+        Lower = IntMin.sdiv(*C);
+        Upper = IntMax.sdiv(*C);
+        if (Lower.sgt(Upper))
+          std::swap(Lower, Upper);
+        Upper = Upper + 1;
+        assert(Upper != Lower && "Upper part of range has wrapped!");
+      }
+    } else if (match(BO.getOperand(0), m_APInt(C))) {
+      if (C->isMinSignedValue()) {
+        // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
+        Lower = *C;
+        Upper = Lower.lshr(1) + 1;
+      } else {
+        // 'sdiv C, x' produces [-|C|, |C|].
+        Upper = C->abs() + 1;
+        Lower = (-Upper) + 1;
+      }
+    }
+    break;
+
+  case Instruction::UDiv:
+    if (match(BO.getOperand(1), m_APInt(C)) && !C->isZero()) {
+      // 'udiv x, C' produces [0, UINT_MAX / C].
+      Upper = APInt::getMaxValue(Width).udiv(*C) + 1;
+    } else if (match(BO.getOperand(0), m_APInt(C))) {
+      // 'udiv C, x' produces [0, C].
+      Upper = *C + 1;
+    }
+    break;
+
+  case Instruction::SRem:
+    if (match(BO.getOperand(1), m_APInt(C))) {
+      // 'srem x, C' produces (-|C|, |C|).
+      Upper = C->abs();
+      Lower = (-Upper) + 1;
+    }
+    break;
+
+  case Instruction::URem:
+    if (match(BO.getOperand(1), m_APInt(C)))
+      // 'urem x, C' produces [0, C).
+      Upper = *C;
+    break;
+
+  default:
+    break;
+  }
+}
+
+static void setLimitsForIntrinsic(const IntrinsicInst &II, APInt &Lower,
+                                  APInt &Upper) {
+  unsigned Width = Lower.getBitWidth();
+  const APInt *C;
+  switch (II.getIntrinsicID()) {
+  case Intrinsic::ctpop:
+  case Intrinsic::ctlz:
+  case Intrinsic::cttz:
+    // Maximum of set/clear bits is the bit width.
+    assert(Lower == 0 && "Expected lower bound to be zero");
+    Upper = Width + 1;
+    break;
+  case Intrinsic::uadd_sat:
+    // uadd.sat(x, C) produces [C, UINT_MAX].
+    if (match(II.getOperand(0), m_APInt(C)) ||
+        match(II.getOperand(1), m_APInt(C)))
+      Lower = *C;
+    break;
+  case Intrinsic::sadd_sat:
+    if (match(II.getOperand(0), m_APInt(C)) ||
+        match(II.getOperand(1), m_APInt(C))) {
+      if (C->isNegative()) {
+        // sadd.sat(x, -C) produces [SINT_MIN, SINT_MAX + (-C)].
+        Lower = APInt::getSignedMinValue(Width);
+        Upper = APInt::getSignedMaxValue(Width) + *C + 1;
+      } else {
+        // sadd.sat(x, +C) produces [SINT_MIN + C, SINT_MAX].
+        Lower = APInt::getSignedMinValue(Width) + *C;
+        Upper = APInt::getSignedMaxValue(Width) + 1;
+      }
+    }
+    break;
+  case Intrinsic::usub_sat:
+    // usub.sat(C, x) produces [0, C].
+    if (match(II.getOperand(0), m_APInt(C)))
+      Upper = *C + 1;
+    // usub.sat(x, C) produces [0, UINT_MAX - C].
+    else if (match(II.getOperand(1), m_APInt(C)))
+      Upper = APInt::getMaxValue(Width) - *C + 1;
+    break;
+  case Intrinsic::ssub_sat:
+    if (match(II.getOperand(0), m_APInt(C))) {
+      if (C->isNegative()) {
+        // ssub.sat(-C, x) produces [SINT_MIN, -SINT_MIN + (-C)].
+        Lower = APInt::getSignedMinValue(Width);
+        Upper = *C - APInt::getSignedMinValue(Width) + 1;
+      } else {
+        // ssub.sat(+C, x) produces [-SINT_MAX + C, SINT_MAX].
+        Lower = *C - APInt::getSignedMaxValue(Width);
+        Upper = APInt::getSignedMaxValue(Width) + 1;
+      }
+    } else if (match(II.getOperand(1), m_APInt(C))) {
+      if (C->isNegative()) {
+        // ssub.sat(x, -C) produces [SINT_MIN - (-C), SINT_MAX]:
+        Lower = APInt::getSignedMinValue(Width) - *C;
+        Upper = APInt::getSignedMaxValue(Width) + 1;
+      } else {
+        // ssub.sat(x, +C) produces [SINT_MIN, SINT_MAX - C].
+        Lower = APInt::getSignedMinValue(Width);
+        Upper = APInt::getSignedMaxValue(Width) - *C + 1;
+      }
+    }
+    break;
+  case Intrinsic::umin:
+  case Intrinsic::umax:
+  case Intrinsic::smin:
+  case Intrinsic::smax:
+    if (!match(II.getOperand(0), m_APInt(C)) &&
+        !match(II.getOperand(1), m_APInt(C)))
+      break;
+
+    switch (II.getIntrinsicID()) {
+    case Intrinsic::umin:
+      Upper = *C + 1;
+      break;
+    case Intrinsic::umax:
+      Lower = *C;
+      break;
+    case Intrinsic::smin:
+      Lower = APInt::getSignedMinValue(Width);
+      Upper = *C + 1;
+      break;
+    case Intrinsic::smax:
+      Lower = *C;
+      Upper = APInt::getSignedMaxValue(Width) + 1;
+      break;
+    default:
+      llvm_unreachable("Must be min/max intrinsic");
+    }
+    break;
+  case Intrinsic::abs:
+    // If abs of SIGNED_MIN is poison, then the result is [0..SIGNED_MAX],
+    // otherwise it is [0..SIGNED_MIN], as -SIGNED_MIN == SIGNED_MIN.
+    if (match(II.getOperand(1), m_One()))
+      Upper = APInt::getSignedMaxValue(Width) + 1;
+    else
+      Upper = APInt::getSignedMinValue(Width) + 1;
+    break;
+  default:
+    break;
+  }
+}
+
+static void setLimitsForSelectPattern(const SelectInst &SI, APInt &Lower,
+                                      APInt &Upper, const InstrInfoQuery &IIQ) {
+  const Value *LHS = nullptr, *RHS = nullptr;
+  SelectPatternResult R = matchSelectPattern(&SI, LHS, RHS);
+  if (R.Flavor == SPF_UNKNOWN)
+    return;
+
+  unsigned BitWidth = SI.getType()->getScalarSizeInBits();
+
+  if (R.Flavor == SelectPatternFlavor::SPF_ABS) {
+    // If the negation part of the abs (in RHS) has the NSW flag,
+    // then the result of abs(X) is [0..SIGNED_MAX],
+    // otherwise it is [0..SIGNED_MIN], as -SIGNED_MIN == SIGNED_MIN.
+    Lower = APInt::getZero(BitWidth);
+    if (match(RHS, m_Neg(m_Specific(LHS))) &&
+        IIQ.hasNoSignedWrap(cast<Instruction>(RHS)))
+      Upper = APInt::getSignedMaxValue(BitWidth) + 1;
+    else
+      Upper = APInt::getSignedMinValue(BitWidth) + 1;
+    return;
+  }
+
+  if (R.Flavor == SelectPatternFlavor::SPF_NABS) {
+    // The result of -abs(X) is <= 0.
+    Lower = APInt::getSignedMinValue(BitWidth);
+    Upper = APInt(BitWidth, 1);
+    return;
+  }
+
+  const APInt *C;
+  if (!match(LHS, m_APInt(C)) && !match(RHS, m_APInt(C)))
+    return;
+
+  switch (R.Flavor) {
+    case SPF_UMIN:
+      Upper = *C + 1;
+      break;
+    case SPF_UMAX:
+      Lower = *C;
+      break;
+    case SPF_SMIN:
+      Lower = APInt::getSignedMinValue(BitWidth);
+      Upper = *C + 1;
+      break;
+    case SPF_SMAX:
+      Lower = *C;
+      Upper = APInt::getSignedMaxValue(BitWidth) + 1;
+      break;
+    default:
+      break;
+  }
+}
+
+static void setLimitForFPToI(const Instruction *I, APInt &Lower, APInt &Upper) {
+  // The maximum representable value of a half is 65504. For floats the maximum
+  // value is 3.4e38 which requires roughly 129 bits.
+  unsigned BitWidth = I->getType()->getScalarSizeInBits();
+  if (!I->getOperand(0)->getType()->getScalarType()->isHalfTy())
+    return;
+  if (isa<FPToSIInst>(I) && BitWidth >= 17) {
+    Lower = APInt(BitWidth, -65504);
+    Upper = APInt(BitWidth, 65505);
+  }
+
+  if (isa<FPToUIInst>(I) && BitWidth >= 16) {
+    // For a fptoui the lower limit is left as 0.
+    Upper = APInt(BitWidth, 65505);
+  }
+}
+
+ConstantRange llvm::computeConstantRange(const Value *V, bool ForSigned,
+                                         bool UseInstrInfo, AssumptionCache *AC,
+                                         const Instruction *CtxI,
+                                         const DominatorTree *DT,
+                                         unsigned Depth) {
+  assert(V->getType()->isIntOrIntVectorTy() && "Expected integer instruction");
+
+  if (Depth == MaxAnalysisRecursionDepth)
+    return ConstantRange::getFull(V->getType()->getScalarSizeInBits());
+
+  const APInt *C;
+  if (match(V, m_APInt(C)))
+    return ConstantRange(*C);
+
+  InstrInfoQuery IIQ(UseInstrInfo);
+  unsigned BitWidth = V->getType()->getScalarSizeInBits();
+  APInt Lower = APInt(BitWidth, 0);
+  APInt Upper = APInt(BitWidth, 0);
+  if (auto *BO = dyn_cast<BinaryOperator>(V))
+    setLimitsForBinOp(*BO, Lower, Upper, IIQ, ForSigned);
+  else if (auto *II = dyn_cast<IntrinsicInst>(V))
+    setLimitsForIntrinsic(*II, Lower, Upper);
+  else if (auto *SI = dyn_cast<SelectInst>(V))
+    setLimitsForSelectPattern(*SI, Lower, Upper, IIQ);
+  else if (isa<FPToUIInst>(V) || isa<FPToSIInst>(V))
+    setLimitForFPToI(cast<Instruction>(V), Lower, Upper);
+
+  ConstantRange CR = ConstantRange::getNonEmpty(Lower, Upper);
+
+  if (auto *I = dyn_cast<Instruction>(V))
+    if (auto *Range = IIQ.getMetadata(I, LLVMContext::MD_range))
+      CR = CR.intersectWith(getConstantRangeFromMetadata(*Range));
+
+  if (CtxI && AC) {
+    // Try to restrict the range based on information from assumptions.
+    for (auto &AssumeVH : AC->assumptionsFor(V)) {
+      if (!AssumeVH)
+        continue;
+      IntrinsicInst *I = cast<IntrinsicInst>(AssumeVH);
+      assert(I->getParent()->getParent() == CtxI->getParent()->getParent() &&
+             "Got assumption for the wrong function!");
+
+      if (!isValidAssumeForContext(I, CtxI, DT))
+        continue;
+      Value *Arg = I->getArgOperand(0);
+      ICmpInst *Cmp = dyn_cast<ICmpInst>(Arg);
+      // Currently we just use information from comparisons.
+      if (!Cmp || Cmp->getOperand(0) != V)
+        continue;
+      // TODO: Set "ForSigned" parameter via Cmp->isSigned()?
+      ConstantRange RHS =
+          computeConstantRange(Cmp->getOperand(1), /* ForSigned */ false,
+                               UseInstrInfo, AC, I, DT, Depth + 1);
+      CR = CR.intersectWith(
+          ConstantRange::makeAllowedICmpRegion(Cmp->getPredicate(), RHS));
+    }
+  }
+
+  return CR;
+}
+
+static std::optional<int64_t>
+getOffsetFromIndex(const GEPOperator *GEP, unsigned Idx, const DataLayout &DL) {
+  // Skip over the first indices.
+  gep_type_iterator GTI = gep_type_begin(GEP);
+  for (unsigned i = 1; i != Idx; ++i, ++GTI)
+    /*skip along*/;
+
+  // Compute the offset implied by the rest of the indices.
+  int64_t Offset = 0;
+  for (unsigned i = Idx, e = GEP->getNumOperands(); i != e; ++i, ++GTI) {
+    ConstantInt *OpC = dyn_cast<ConstantInt>(GEP->getOperand(i));
+    if (!OpC)
+      return std::nullopt;
+    if (OpC->isZero())
+      continue; // No offset.
+
+    // Handle struct indices, which add their field offset to the pointer.
+    if (StructType *STy = GTI.getStructTypeOrNull()) {
+      Offset += DL.getStructLayout(STy)->getElementOffset(OpC->getZExtValue());
+      continue;
+    }
+
+    // Otherwise, we have a sequential type like an array or fixed-length
+    // vector. Multiply the index by the ElementSize.
+    TypeSize Size = DL.getTypeAllocSize(GTI.getIndexedType());
+    if (Size.isScalable())
+      return std::nullopt;
+    Offset += Size.getFixedValue() * OpC->getSExtValue();
+  }
+
+  return Offset;
+}
+
+std::optional<int64_t> llvm::isPointerOffset(const Value *Ptr1,
+                                             const Value *Ptr2,
+                                             const DataLayout &DL) {
+  APInt Offset1(DL.getIndexTypeSizeInBits(Ptr1->getType()), 0);
+  APInt Offset2(DL.getIndexTypeSizeInBits(Ptr2->getType()), 0);
+  Ptr1 = Ptr1->stripAndAccumulateConstantOffsets(DL, Offset1, true);
+  Ptr2 = Ptr2->stripAndAccumulateConstantOffsets(DL, Offset2, true);
+
+  // Handle the trivial case first.
+  if (Ptr1 == Ptr2)
+    return Offset2.getSExtValue() - Offset1.getSExtValue();
+
+  const GEPOperator *GEP1 = dyn_cast<GEPOperator>(Ptr1);
+  const GEPOperator *GEP2 = dyn_cast<GEPOperator>(Ptr2);
+
+  // Right now we handle the case when Ptr1/Ptr2 are both GEPs with an identical
+  // base.  After that base, they may have some number of common (and
+  // potentially variable) indices.  After that they handle some constant
+  // offset, which determines their offset from each other.  At this point, we
+  // handle no other case.
+  if (!GEP1 || !GEP2 || GEP1->getOperand(0) != GEP2->getOperand(0) ||
+      GEP1->getSourceElementType() != GEP2->getSourceElementType())
+    return std::nullopt;
+
+  // Skip any common indices and track the GEP types.
+  unsigned Idx = 1;
+  for (; Idx != GEP1->getNumOperands() && Idx != GEP2->getNumOperands(); ++Idx)
+    if (GEP1->getOperand(Idx) != GEP2->getOperand(Idx))
+      break;
+
+  auto IOffset1 = getOffsetFromIndex(GEP1, Idx, DL);
+  auto IOffset2 = getOffsetFromIndex(GEP2, Idx, DL);
+  if (!IOffset1 || !IOffset2)
+    return std::nullopt;
+  return *IOffset2 - *IOffset1 + Offset2.getSExtValue() -
+         Offset1.getSExtValue();
+}