/build/source/llvm/lib/Analysis/ValueTracking.cpp

Bug Summary

File:	build/source/llvm/lib/Analysis/ValueTracking.cpp
Warning:	line 5641, column 22 Called C++ object pointer is null
Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name ValueTracking.cpp -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/source/build-llvm -resource-dir /usr/lib/llvm-17/lib/clang/17 -I lib/Analysis -I /build/source/llvm/lib/Analysis -I include -I /build/source/llvm/include -D _DEBUG -D _GLIBCXX_ASSERTIONS -D _GNU_SOURCE -D _LIBCPP_ENABLE_ASSERTIONS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-17/lib/clang/17/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/source/build-llvm=build-llvm -fmacro-prefix-map=/build/source/= -fcoverage-prefix-map=/build/source/build-llvm=build-llvm -fcoverage-prefix-map=/build/source/= -O3 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -Wno-misleading-indentation -std=c++17 -fdeprecated-macro -fdebug-compilation-dir=/build/source/build-llvm -fdebug-prefix-map=/build/source/build-llvm=build-llvm -fdebug-prefix-map=/build/source/= -fdebug-prefix-map=/build/source/build-llvm=build-llvm -fdebug-prefix-map=/build/source/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2023-05-10-133810-16478-1 -x c++ /build/source/llvm/lib/Analysis/ValueTracking.cpp
1//===- ValueTracking.cpp - Walk computations to compute properties --------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains routines that help analyze properties that chains of
10// computations have.
11//
12//===----------------------------------------------------------------------===//

14#include "llvm/Analysis/ValueTracking.h"
15#include "llvm/ADT/APFloat.h"
16#include "llvm/ADT/APInt.h"
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/STLExtras.h"
19#include "llvm/ADT/ScopeExit.h"
20#include "llvm/ADT/SmallPtrSet.h"
21#include "llvm/ADT/SmallSet.h"
22#include "llvm/ADT/SmallVector.h"
23#include "llvm/ADT/StringRef.h"
24#include "llvm/ADT/iterator_range.h"
25#include "llvm/Analysis/AliasAnalysis.h"
26#include "llvm/Analysis/AssumeBundleQueries.h"
27#include "llvm/Analysis/AssumptionCache.h"
28#include "llvm/Analysis/ConstantFolding.h"
29#include "llvm/Analysis/GuardUtils.h"
30#include "llvm/Analysis/InstructionSimplify.h"
31#include "llvm/Analysis/Loads.h"
32#include "llvm/Analysis/LoopInfo.h"
33#include "llvm/Analysis/OptimizationRemarkEmitter.h"
34#include "llvm/Analysis/TargetLibraryInfo.h"
35#include "llvm/Analysis/VectorUtils.h"
36#include "llvm/IR/Argument.h"
37#include "llvm/IR/Attributes.h"
38#include "llvm/IR/BasicBlock.h"
39#include "llvm/IR/Constant.h"
40#include "llvm/IR/ConstantRange.h"
41#include "llvm/IR/Constants.h"
42#include "llvm/IR/DerivedTypes.h"
43#include "llvm/IR/DiagnosticInfo.h"
44#include "llvm/IR/Dominators.h"
45#include "llvm/IR/EHPersonalities.h"
46#include "llvm/IR/Function.h"
47#include "llvm/IR/GetElementPtrTypeIterator.h"
48#include "llvm/IR/GlobalAlias.h"
49#include "llvm/IR/GlobalValue.h"
50#include "llvm/IR/GlobalVariable.h"
51#include "llvm/IR/InstrTypes.h"
52#include "llvm/IR/Instruction.h"
53#include "llvm/IR/Instructions.h"
54#include "llvm/IR/IntrinsicInst.h"
55#include "llvm/IR/Intrinsics.h"
56#include "llvm/IR/IntrinsicsAArch64.h"
57#include "llvm/IR/IntrinsicsRISCV.h"
58#include "llvm/IR/IntrinsicsX86.h"
59#include "llvm/IR/LLVMContext.h"
60#include "llvm/IR/Metadata.h"
61#include "llvm/IR/Module.h"
62#include "llvm/IR/Operator.h"
63#include "llvm/IR/PatternMatch.h"
64#include "llvm/IR/Type.h"
65#include "llvm/IR/User.h"
66#include "llvm/IR/Value.h"
67#include "llvm/Support/Casting.h"
68#include "llvm/Support/CommandLine.h"
69#include "llvm/Support/Compiler.h"
70#include "llvm/Support/ErrorHandling.h"
71#include "llvm/Support/KnownBits.h"
72#include "llvm/Support/MathExtras.h"
73#include <algorithm>
74#include <cassert>
75#include <cstdint>
76#include <optional>
77#include <utility>

79using namespace llvm;
80using namespace llvm::PatternMatch;

82// Controls the number of uses of the value searched for possible
83// dominating comparisons.
84static cl::opt<unsigned> DomConditionsMaxUses("dom-conditions-max-uses",
                                            cl::Hidden, cl::init(20));


88/// Returns the bitwidth of the given scalar or pointer type. For vector types,
89/// returns the element type's bitwidth.
90static unsigned getBitWidth(Type *Ty, const DataLayout &DL) {
if (unsigned BitWidth = Ty->getScalarSizeInBits())
  return BitWidth;

return DL.getPointerTypeSizeInBits(Ty);
95}

97namespace {

99// Simplifying using an assume can only be done in a particular control-flow
100// context (the context instruction provides that context). If an assume and
101// the context instruction are not in the same block then the DT helps in
102// figuring out if we can use it.
103struct 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) {}
120};

122} // end anonymous namespace

124// Given the provided Value and, potentially, a context instruction, return
125// the preferred context instruction (if any).
126static 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;
138}

140static 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;
156}

158static bool getShuffleDemandedElts(const ShuffleVectorInst *Shuf,
                                 const APInt &DemandedElts,
                                 APInt &DemandedLHS, APInt &DemandedRHS) {
if (isa<ScalableVectorType>(Shuf->getType())) {
  assert(DemandedElts == APInt(1,1))(static_cast <bool> (DemandedElts == APInt(1,1)) ? void
 (0) : __assert_fail ("DemandedElts == APInt(1,1)", "llvm/lib/Analysis/ValueTracking.cpp"
, 162, __extension__ __PRETTY_FUNCTION__));
  DemandedLHS = DemandedRHS = DemandedElts;
  return true;
}

int NumElts =
    cast<FixedVectorType>(Shuf->getOperand(0)->getType())->getNumElements();
return llvm::getShuffleDemandedElts(NumElts, Shuf->getShuffleMask(),
                                    DemandedElts, DemandedLHS, DemandedRHS);
171}

173static void computeKnownBits(const Value *V, const APInt &DemandedElts,
                           KnownBits &Known, unsigned Depth, const Query &Q);

176static 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);
185}

187void 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));
194}

196void 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));
203}

205static KnownBits computeKnownBits(const Value *V, const APInt &DemandedElts,
                                unsigned Depth, const Query &Q);

208static KnownBits computeKnownBits(const Value *V, unsigned Depth,
                                const Query &Q);

211KnownBits 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));
219}

221KnownBits 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));
230}

232bool 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() &&(static_cast <bool> (LHS->getType() == RHS->getType
() && "LHS and RHS should have the same type") ? void
 (0) : __assert_fail ("LHS->getType() == RHS->getType() && \"LHS and RHS should have the same type\""
, "llvm/lib/Analysis/ValueTracking.cpp", 237, __extension__ __PRETTY_FUNCTION__
))
       "LHS and RHS should have the same type")(static_cast <bool> (LHS->getType() == RHS->getType
() && "LHS and RHS should have the same type") ? void
 (0) : __assert_fail ("LHS->getType() == RHS->getType() && \"LHS and RHS should have the same type\""
, "llvm/lib/Analysis/ValueTracking.cpp", 237, __extension__ __PRETTY_FUNCTION__
));
assert(LHS->getType()->isIntOrIntVectorTy() &&(static_cast <bool> (LHS->getType()->isIntOrIntVectorTy
() && "LHS and RHS should be integers") ? void (0) : __assert_fail
 ("LHS->getType()->isIntOrIntVectorTy() && \"LHS and RHS should be integers\""
, "llvm/lib/Analysis/ValueTracking.cpp", 239, __extension__ __PRETTY_FUNCTION__
))
       "LHS and RHS should be integers")(static_cast <bool> (LHS->getType()->isIntOrIntVectorTy
() && "LHS and RHS should be integers") ? void (0) : __assert_fail
 ("LHS->getType()->isIntOrIntVectorTy() && \"LHS and RHS should be integers\""
, "llvm/lib/Analysis/ValueTracking.cpp", 239, __extension__ __PRETTY_FUNCTION__
));
// 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);
289}

291bool 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);
});
296}

298static bool isKnownToBeAPowerOfTwo(const Value *V, bool OrZero, unsigned Depth,
                                 const Query &Q);

301bool 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));
307}

309static bool isKnownNonZero(const Value *V, const APInt &DemandedElts,
                         unsigned Depth, const Query &Q);

312static bool isKnownNonZero(const Value *V, unsigned Depth, const Query &Q);

314bool 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));
319}

321bool 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();
328}

330bool 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);
340}

342bool 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();
348}

350static bool isKnownNonEqual(const Value *V1, const Value *V2, unsigned Depth,
                          const Query &Q);

353bool 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));
360}

362static bool MaskedValueIsZero(const Value *V, const APInt &Mask, unsigned Depth,
                            const Query &Q);

365bool 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));
371}

373static unsigned ComputeNumSignBits(const Value *V, const APInt &DemandedElts,
                                 unsigned Depth, const Query &Q);

376static 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);
382}

384unsigned 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));
390}

392unsigned 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;
398}

400static 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);
413}

415static 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();
463}

465void llvm::computeKnownBitsFromRangeMetadata(const MDNode &Ranges,
                                           KnownBits &Known) {
unsigned BitWidth = Known.getBitWidth();
unsigned NumRanges = Ranges.getNumOperands() / 2;
assert(NumRanges >= 1)(static_cast <bool> (NumRanges >= 1) ? void (0) : __assert_fail
 ("NumRanges >= 1", "llvm/lib/Analysis/ValueTracking.cpp",
 469, __extension__ __PRETTY_FUNCTION__));

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()).countl_zero();
  APInt Mask = APInt::getHighBitsSet(BitWidth, CommonPrefixBits);
  APInt UnsignedMax = Range.getUnsignedMax().zextOrTrunc(BitWidth);
  Known.One &= UnsignedMax & Mask;
  Known.Zero &= ~UnsignedMax & Mask;
}
489}

491static 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;
525}

527// Is this an intrinsic that cannot be speculated but also cannot trap?
528bool llvm::isAssumeLikeIntrinsic(const Instruction *I) {
if (const IntrinsicInst *CI = dyn_cast<IntrinsicInst>(I))
  return CI->isAssumeLikeIntrinsic();

return false;
533}

535bool 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;
581}

583static 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()));
599}

601static 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;
  CallInst *I = cast<CallInst>(AssumeVH);
  assert(I->getFunction() == Q.CxtI->getFunction() &&(static_cast <bool> (I->getFunction() == Q.CxtI->
getFunction() && "Got assumption for the wrong function!"
) ? void (0) : __assert_fail ("I->getFunction() == Q.CxtI->getFunction() && \"Got assumption for the wrong function!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 622, __extension__ __PRETTY_FUNCTION__
))
         "Got assumption for the wrong function!")(static_cast <bool> (I->getFunction() == Q.CxtI->
getFunction() && "Got assumption for the wrong function!"
) ? void (0) : __assert_fail ("I->getFunction() == Q.CxtI->getFunction() && \"Got assumption for the wrong function!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 622, __extension__ __PRETTY_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).

  assert(I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume &&(static_cast <bool> (I->getCalledFunction()->getIntrinsicID
() == Intrinsic::assume && "must be an assume intrinsic"
) ? void (0) : __assert_fail ("I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume && \"must be an assume intrinsic\""
, "llvm/lib/Analysis/ValueTracking.cpp", 629, __extension__ __PRETTY_FUNCTION__
))
         "must be an assume intrinsic")(static_cast <bool> (I->getCalledFunction()->getIntrinsicID
() == Intrinsic::assume && "must be an assume intrinsic"
) ? void (0) : __assert_fail ("I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume && \"must be an assume intrinsic\""
, "llvm/lib/Analysis/ValueTracking.cpp", 629, __extension__ __PRETTY_FUNCTION__
));

  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;
642}

644static void computeKnownBitsFromCmp(const Value *V, const ICmpInst *Cmp,
                                  KnownBits &Known, unsigned Depth,
                                  const Query &Q) {
unsigned BitWidth = Known.getBitWidth();
// 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)))) {
    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)))) {
    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)))) {
    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)))) {
    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)))) {
    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)))) {
    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)))) {
    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))) &&
             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))) &&
             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))) &&
             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))) &&
             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)))) {
    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)))) {
    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)))) {
    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)))) {
    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)))) {
    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)))) {
    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()))) {
    Known.One |= BPow2->zextOrTrunc(BitWidth);
  }
} break;
}
886}

888static 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;
  CallInst *I = cast<CallInst>(AssumeVH);
  assert(I->getParent()->getParent() == Q.CxtI->getParent()->getParent() &&(static_cast <bool> (I->getParent()->getParent() ==
 Q.CxtI->getParent()->getParent() && "Got assumption for the wrong function!"
) ? void (0) : __assert_fail ("I->getParent()->getParent() == Q.CxtI->getParent()->getParent() && \"Got assumption for the wrong function!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 914, __extension__ __PRETTY_FUNCTION__
))
         "Got assumption for the wrong function!")(static_cast <bool> (I->getParent()->getParent() ==
 Q.CxtI->getParent()->getParent() && "Got assumption for the wrong function!"
) ? void (0) : __assert_fail ("I->getParent()->getParent() == Q.CxtI->getParent()->getParent() && \"Got assumption for the wrong function!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 914, __extension__ __PRETTY_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).

  assert(I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume &&(static_cast <bool> (I->getCalledFunction()->getIntrinsicID
() == Intrinsic::assume && "must be an assume intrinsic"
) ? void (0) : __assert_fail ("I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume && \"must be an assume intrinsic\""
, "llvm/lib/Analysis/ValueTracking.cpp", 921, __extension__ __PRETTY_FUNCTION__
))
         "must be an assume intrinsic")(static_cast <bool> (I->getCalledFunction()->getIntrinsicID
() == Intrinsic::assume && "must be an assume intrinsic"
) ? void (0) : __assert_fail ("I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume && \"must be an assume intrinsic\""
, "llvm/lib/Analysis/ValueTracking.cpp", 921, __extension__ __PRETTY_FUNCTION__
));

  Value *Arg = I->getArgOperand(0);

  if (Arg == V && isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
    assert(BitWidth == 1 && "assume operand is not i1?")(static_cast <bool> (BitWidth == 1 && "assume operand is not i1?"
) ? void (0) : __assert_fail ("BitWidth == 1 && \"assume operand is not i1?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 926, __extension__ __PRETTY_FUNCTION__
));
    (void)BitWidth;
    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?")(static_cast <bool> (BitWidth == 1 && "assume operand is not i1?"
) ? void (0) : __assert_fail ("BitWidth == 1 && \"assume operand is not i1?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 933, __extension__ __PRETTY_FUNCTION__
));
    (void)BitWidth;
    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;

  if (!isValidAssumeForContext(I, Q.CxtI, Q.DT))
    continue;

  computeKnownBitsFromCmp(V, Cmp, Known, Depth, Q);
}

// 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.";
    });
}
971}

973/// Compute known bits from a shift operator, including those with a
974/// non-constant shift amount. Known is the output of this function. Known2 is a
975/// pre-allocated temporary with the same bit width as Known and on return
976/// contains the known bit of the shift value source. KF is an
977/// operator-specific function that, given the known-bits and a shift amount,
978/// compute the implied known-bits of the shift operator's result respectively
979/// for that shift amount. The results from calling KF are conservatively
980/// combined for all permitted shift amounts.
981static 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();
1064}

1066static KnownBits getKnownBitsFromAndXorOr(const Operator *I,
                                        const APInt &DemandedElts,
                                        const KnownBits &KnownLHS,
                                        const KnownBits &KnownRHS,
                                        unsigned Depth, const Query &Q) {
unsigned BitWidth = KnownLHS.getBitWidth();
KnownBits KnownOut(BitWidth);
bool IsAnd = false;
bool HasKnownOne = !KnownLHS.One.isZero() || !KnownRHS.One.isZero();
Value *X = nullptr, *Y = nullptr;

switch (I->getOpcode()) {
case Instruction::And:
  KnownOut = KnownLHS & KnownRHS;
  IsAnd = true;
  // and(x, -x) is common idioms that will clear all but lowest set
  // bit. If we have a single known bit in x, we can clear all bits
  // above it.
  // TODO: instcombine often reassociates independent `and` which can hide
  // this pattern. Try to match and(x, and(-x, y)) / and(and(x, y), -x).
  if (HasKnownOne && match(I, m_c_And(m_Value(X), m_Neg(m_Deferred(X))))) {
    // -(-x) == x so using whichever (LHS/RHS) gets us a better result.
    if (KnownLHS.countMaxTrailingZeros() <= KnownRHS.countMaxTrailingZeros())
      KnownOut = KnownLHS.blsi();
    else
      KnownOut = KnownRHS.blsi();
  }
  break;
case Instruction::Or:
  KnownOut = KnownLHS | KnownRHS;
  break;
case Instruction::Xor:
  KnownOut = KnownLHS ^ KnownRHS;
  // xor(x, x-1) is common idioms that will clear all but lowest set
  // bit. If we have a single known bit in x, we can clear all bits
  // above it.
  // TODO: xor(x, x-1) is often rewritting as xor(x, x-C) where C !=
  // -1 but for the purpose of demanded bits (xor(x, x-C) &
  // Demanded) == (xor(x, x-1) & Demanded). Extend the xor pattern
  // to use arbitrary C if xor(x, x-C) as the same as xor(x, x-1).
  if (HasKnownOne &&
      match(I, m_c_Xor(m_Value(X), m_c_Add(m_Deferred(X), m_AllOnes())))) {
    const KnownBits &XBits = I->getOperand(0) == X ? KnownLHS : KnownRHS;
    KnownOut = XBits.blsmsk();
  }
  break;
default:
  llvm_unreachable("Invalid Op used in 'analyzeKnownBitsFromAndXorOr'")::llvm::llvm_unreachable_internal("Invalid Op used in 'analyzeKnownBitsFromAndXorOr'"
, "llvm/lib/Analysis/ValueTracking.cpp", 1113);
}

// and(x, add (x, -1)) is a common idiom that always clears the low bit;
// xor/or(x, add (x, -1)) is an idiom that will always set the low bit.
// here we handle the more general case of adding any odd number by
// matching the form and/xor/or(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.
if (!KnownOut.Zero[0] && !KnownOut.One[0] &&
    (match(I, m_c_BinOp(m_Value(X), m_c_Add(m_Deferred(X), m_Value(Y)))) ||
     match(I, m_c_BinOp(m_Value(X), m_Sub(m_Deferred(X), m_Value(Y)))) ||
     match(I, m_c_BinOp(m_Value(X), m_Sub(m_Value(Y), m_Deferred(X)))))) {
  KnownBits KnownY(BitWidth);
  computeKnownBits(Y, DemandedElts, KnownY, Depth + 1, Q);
  if (KnownY.countMinTrailingOnes() > 0) {
    if (IsAnd)
      KnownOut.Zero.setBit(0);
    else
      KnownOut.One.setBit(0);
  }
}
return KnownOut;
1136}

1138// Public so this can be used in `SimplifyDemandedUseBits`.
1139KnownBits llvm::analyzeKnownBitsFromAndXorOr(
  const Operator *I, const KnownBits &KnownLHS, const KnownBits &KnownRHS,
  unsigned Depth, const DataLayout &DL, AssumptionCache *AC,
  const Instruction *CxtI, const DominatorTree *DT,
  OptimizationRemarkEmitter *ORE, bool UseInstrInfo) {
auto *FVTy = dyn_cast<FixedVectorType>(I->getType());
APInt DemandedElts =
    FVTy ? APInt::getAllOnes(FVTy->getNumElements()) : APInt(1, 1);

return getKnownBitsFromAndXorOr(
    I, DemandedElts, KnownLHS, KnownRHS, Depth,
    Query(DL, AC, safeCxtI(I, CxtI), DT, UseInstrInfo, ORE));
1151}

1153ConstantRange llvm::getVScaleRange(const Function *F, unsigned BitWidth) {
Attribute Attr = F->getFnAttribute(Attribute::VScaleRange);
// Without vscale_range, we only know that vscale is non-zero.
if (!Attr.isValid())
  return ConstantRange(APInt(BitWidth, 1), APInt::getZero(BitWidth));

unsigned AttrMin = Attr.getVScaleRangeMin();
// Minimum is larger than vscale width, result is always poison.
if ((unsigned)llvm::bit_width(AttrMin) > BitWidth)
  return ConstantRange::getEmpty(BitWidth);

APInt Min(BitWidth, AttrMin);
std::optional<unsigned> AttrMax = Attr.getVScaleRangeMax();
if (!AttrMax || (unsigned)llvm::bit_width(*AttrMax) > BitWidth)
  return ConstantRange(Min, APInt::getZero(BitWidth));

return ConstantRange(Min, APInt(BitWidth, *AttrMax) + 1);
1170}

1172static 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:
  computeKnownBits(I->getOperand(1), DemandedElts, Known, Depth + 1, Q);
  computeKnownBits(I->getOperand(0), DemandedElts, Known2, Depth + 1, Q);

  Known = getKnownBitsFromAndXorOr(I, DemandedElts, Known2, Known, Depth, Q);
  break;
case Instruction::Or:
  computeKnownBits(I->getOperand(1), DemandedElts, Known, Depth + 1, Q);
  computeKnownBits(I->getOperand(0), DemandedElts, Known2, Depth + 1, Q);

  Known = getKnownBitsFromAndXorOr(I, DemandedElts, Known2, Known, Depth, Q);
  break;
case Instruction::Xor:
  computeKnownBits(I->getOperand(1), DemandedElts, Known, Depth + 1, Q);
  computeKnownBits(I->getOperand(0), DemandedElts, Known2, Depth + 1, Q);

  Known = getKnownBitsFromAndXorOr(I, DemandedElts, Known2, Known, Depth, Q);
  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!")::llvm::llvm_unreachable_internal("Unhandled select pattern flavor!"
, "llvm/lib/Analysis/ValueTracking.cpp", 1224);
    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")(static_cast <bool> (SrcBitWidth && "SrcBitWidth can't be zero"
) ? void (0) : __assert_fail ("SrcBitWidth && \"SrcBitWidth can't be zero\""
, "llvm/lib/Analysis/ValueTracking.cpp", 1281, __extension__ __PRETTY_FUNCTION__
));
  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->countr_zero());
  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->countl_zero());
  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 &&(static_cast <bool> (CIndex && "Access to structure field must be known at compile time"
) ? void (0) : __assert_fail ("CIndex && \"Access to structure field must be known at compile time\""
, "llvm/lib/Analysis/ValueTracking.cpp", 1444, __extension__ __PRETTY_FUNCTION__
))
             "Access to structure field must be known at compile time")(static_cast <bool> (CIndex && "Access to structure field must be known at compile time"
) ? void (0) : __assert_fail ("CIndex && \"Access to structure field must be known at compile time\""
, "llvm/lib/Analysis/ValueTracking.cpp", 1444, __extension__ __PRETTY_FUNCTION__
));

      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(llvm::countr_zero(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->countl_zero());
              break;
            case CmpInst::Predicate::ICMP_ULT:
              Known2.Zero.setHighBits((*RHSC - 1).countl_zero());
              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 >= 65536.
      // TODO: Take SEW and LMUL into account.
      if (BitWidth > 17)
        Known.Zero.setBitsFrom(17);
      break;
    case Intrinsic::vscale: {
      if (!II->getParent() || !II->getFunction())
        break;

      Known = getVScaleRange(II->getFunction(), BitWidth).toKnownBits();
      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;
}
1964}

1966/// Determine which bits of V are known to be either zero or one and return
1967/// them.
1968KnownBits 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;
1973}

1975/// Determine which bits of V are known to be either zero or one and return
1976/// them.
1977KnownBits computeKnownBits(const Value *V, unsigned Depth, const Query &Q) {
KnownBits Known(getBitWidth(V->getType(), Q.DL));
computeKnownBits(V, Known, Depth, Q);
return Known;
1981}

1983/// Determine which bits of V are known to be either zero or one and return
1984/// them in the Known bit set.
1985///
1986/// NOTE: we cannot consider 'undef' to be "IsZero" here.  The problem is that
1987/// we cannot optimize based on the assumption that it is zero without changing
1988/// it to be an explicit zero.  If we don't change it to zero, other code could
1989/// optimized based on the contradictory assumption that it is non-zero.
1990/// Because instcombine aggressively folds operations with undef args anyway,
1991/// this won't lose us code quality.
1992///
1993/// This function is defined on values with integer type, values with pointer
1994/// type, and vectors of integers.  In the case
1995/// where V is a vector, known zero, and known one values are the
1996/// same width as the vector element, and the bit is set only if it is true
1997/// for all of the demanded elements in the vector specified by DemandedElts.
1998void 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?")(static_cast <bool> (V && "No Value?") ? void (
0) : __assert_fail ("V && \"No Value?\"", "llvm/lib/Analysis/ValueTracking.cpp"
, 2006, __extension__ __PRETTY_FUNCTION__));
assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth")(static_cast <bool> (Depth <= MaxAnalysisRecursionDepth
 && "Limit Search Depth") ? void (0) : __assert_fail (
"Depth <= MaxAnalysisRecursionDepth && \"Limit Search Depth\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2007, __extension__ __PRETTY_FUNCTION__
));

2009#ifndef NDEBUG
Type *Ty = V->getType();
unsigned BitWidth = Known.getBitWidth();

assert((Ty->isIntOrIntVectorTy(BitWidth) || Ty->isPtrOrPtrVectorTy()) &&(static_cast <bool> ((Ty->isIntOrIntVectorTy(BitWidth
) || Ty->isPtrOrPtrVectorTy()) && "Not integer or pointer type!"
) ? void (0) : __assert_fail ("(Ty->isIntOrIntVectorTy(BitWidth) || Ty->isPtrOrPtrVectorTy()) && \"Not integer or pointer type!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2014, __extension__ __PRETTY_FUNCTION__
))
       "Not integer or pointer type!")(static_cast <bool> ((Ty->isIntOrIntVectorTy(BitWidth
) || Ty->isPtrOrPtrVectorTy()) && "Not integer or pointer type!"
) ? void (0) : __assert_fail ("(Ty->isIntOrIntVectorTy(BitWidth) || Ty->isPtrOrPtrVectorTy()) && \"Not integer or pointer type!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2014, __extension__ __PRETTY_FUNCTION__
));

if (auto *FVTy = dyn_cast<FixedVectorType>(Ty)) {
  assert((static_cast <bool> (FVTy->getNumElements() == DemandedElts
.getBitWidth() && "DemandedElt width should equal the fixed vector number of elements"
) ? void (0) : __assert_fail ("FVTy->getNumElements() == DemandedElts.getBitWidth() && \"DemandedElt width should equal the fixed vector number of elements\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2019, __extension__ __PRETTY_FUNCTION__
))
      FVTy->getNumElements() == DemandedElts.getBitWidth() &&(static_cast <bool> (FVTy->getNumElements() == DemandedElts
.getBitWidth() && "DemandedElt width should equal the fixed vector number of elements"
) ? void (0) : __assert_fail ("FVTy->getNumElements() == DemandedElts.getBitWidth() && \"DemandedElt width should equal the fixed vector number of elements\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2019, __extension__ __PRETTY_FUNCTION__
))
      "DemandedElt width should equal the fixed vector number of elements")(static_cast <bool> (FVTy->getNumElements() == DemandedElts
.getBitWidth() && "DemandedElt width should equal the fixed vector number of elements"
) ? void (0) : __assert_fail ("FVTy->getNumElements() == DemandedElts.getBitWidth() && \"DemandedElt width should equal the fixed vector number of elements\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2019, __extension__ __PRETTY_FUNCTION__
));
} else {
  assert(DemandedElts == APInt(1, 1) &&(static_cast <bool> (DemandedElts == APInt(1, 1) &&
 "DemandedElt width should be 1 for scalars or scalable vectors"
) ? void (0) : __assert_fail ("DemandedElts == APInt(1, 1) && \"DemandedElt width should be 1 for scalars or scalable vectors\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2022, __extension__ __PRETTY_FUNCTION__
))
         "DemandedElt width should be 1 for scalars or scalable vectors")(static_cast <bool> (DemandedElts == APInt(1, 1) &&
 "DemandedElt width should be 1 for scalars or scalable vectors"
) ? void (0) : __assert_fail ("DemandedElts == APInt(1, 1) && \"DemandedElt width should be 1 for scalars or scalable vectors\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2022, __extension__ __PRETTY_FUNCTION__
));
}

Type *ScalarTy = Ty->getScalarType();
if (ScalarTy->isPointerTy()) {
  assert(BitWidth == Q.DL.getPointerTypeSizeInBits(ScalarTy) &&(static_cast <bool> (BitWidth == Q.DL.getPointerTypeSizeInBits
(ScalarTy) && "V and Known should have same BitWidth"
) ? void (0) : __assert_fail ("BitWidth == Q.DL.getPointerTypeSizeInBits(ScalarTy) && \"V and Known should have same BitWidth\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2028, __extension__ __PRETTY_FUNCTION__
))
         "V and Known should have same BitWidth")(static_cast <bool> (BitWidth == Q.DL.getPointerTypeSizeInBits
(ScalarTy) && "V and Known should have same BitWidth"
) ? void (0) : __assert_fail ("BitWidth == Q.DL.getPointerTypeSizeInBits(ScalarTy) && \"V and Known should have same BitWidth\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2028, __extension__ __PRETTY_FUNCTION__
));
} else {
  assert(BitWidth == Q.DL.getTypeSizeInBits(ScalarTy) &&(static_cast <bool> (BitWidth == Q.DL.getTypeSizeInBits
(ScalarTy) && "V and Known should have same BitWidth"
) ? void (0) : __assert_fail ("BitWidth == Q.DL.getTypeSizeInBits(ScalarTy) && \"V and Known should have same BitWidth\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2031, __extension__ __PRETTY_FUNCTION__
))
         "V and Known should have same BitWidth")(static_cast <bool> (BitWidth == Q.DL.getTypeSizeInBits
(ScalarTy) && "V and Known should have same BitWidth"
) ? void (0) : __assert_fail ("BitWidth == Q.DL.getTypeSizeInBits(ScalarTy) && \"V and Known should have same BitWidth\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2031, __extension__ __PRETTY_FUNCTION__
));
}
2033#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()))(static_cast <bool> (!isa<ScalableVectorType>(V->
getType())) ? void (0) : __assert_fail ("!isa<ScalableVectorType>(V->getType())"
, "llvm/lib/Analysis/ValueTracking.cpp", 2049, __extension__ __PRETTY_FUNCTION__
));
  // 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()))(static_cast <bool> (!isa<ScalableVectorType>(V->
getType())) ? void (0) : __assert_fail ("!isa<ScalableVectorType>(V->getType())"
, "llvm/lib/Analysis/ValueTracking.cpp", 2064, __extension__ __PRETTY_FUNCTION__
));
  // 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!")(static_cast <bool> (!isa<ConstantData>(V) &&
 "Unhandled constant data!") ? void (0) : __assert_fail ("!isa<ConstantData>(V) && \"Unhandled constant data!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2093, __extension__ __PRETTY_FUNCTION__
));

// 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?")(static_cast <bool> ((Known.Zero & Known.One) == 0 &&
 "Bits known to be one AND zero?") ? void (0) : __assert_fail
 ("(Known.Zero & Known.One) == 0 && \"Bits known to be one AND zero?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2122, __extension__ __PRETTY_FUNCTION__
));
2123}

2125/// Try to detect a recurrence that the value of the induction variable is
2126/// always a power of two (or zero).
2127static 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;
}
2180}

2182/// Return true if the given value is known to have exactly one
2183/// bit set when defined. For vectors return true if every element is known to
2184/// be a power of two when defined. Supports values with integer or pointer
2185/// types and vectors of integers.
2186bool isKnownToBeAPowerOfTwo(const Value *V, bool OrZero, unsigned Depth,
                          const Query &Q) {
assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth")(static_cast <bool> (Depth <= MaxAnalysisRecursionDepth
 && "Limit Search Depth") ? void (0) : __assert_fail (
"Depth <= MaxAnalysisRecursionDepth && \"Limit Search Depth\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2188, __extension__ __PRETTY_FUNCTION__
));

// 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;
2307}

2309/// Test whether a GEP's result is known to be non-null.
2310///
2311/// Uses properties inherent in a GEP to try to determine whether it is known
2312/// to be non-null.
2313///
2314/// Currently this routine does not support vector GEPs.
2315static 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")(static_cast <bool> (GEP->getType()->isPointerTy(
) && "We only support plain pointer GEP") ? void (0) :
 __assert_fail ("GEP->getType()->isPointerTy() && \"We only support plain pointer GEP\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2326, __extension__ __PRETTY_FUNCTION__
));

// 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;
2374}

2376static bool isKnownNonNullFromDominatingCondition(const Value *V,
                                                const Instruction *CtxI,
                                                const DominatorTree *DT) {
assert(!isa<Constant>(V) && "Called for constant?")(static_cast <bool> (!isa<Constant>(V) &&
 "Called for constant?") ? void (0) : __assert_fail ("!isa<Constant>(V) && \"Called for constant?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2379, __extension__ __PRETTY_FUNCTION__
));

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!")(static_cast <bool> (WorkList.empty() && "Should be!"
) ? void (0) : __assert_fail ("WorkList.empty() && \"Should be!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2427, __extension__ __PRETTY_FUNCTION__
));
    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!")(static_cast <bool> (BI->isConditional() && "uses a comparison!"
) ? void (0) : __assert_fail ("BI->isConditional() && \"uses a comparison!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2447, __extension__ __PRETTY_FUNCTION__
));

        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;
2463}

2465/// Does the 'Range' metadata (which must be a valid MD_range operand list)
2466/// ensure that the value it's attached to is never Value?  'RangeType' is
2467/// is the type of the value described by the range.
2468static bool rangeMetadataExcludesValue(const MDNode* Ranges, const APInt& Value) {
const unsigned NumRanges = Ranges->getNumOperands() / 2;
assert(NumRanges >= 1)(static_cast <bool> (NumRanges >= 1) ? void (0) : __assert_fail
 ("NumRanges >= 1", "llvm/lib/Analysis/ValueTracking.cpp",
 2470, __extension__ __PRETTY_FUNCTION__));
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;
2481}

2483/// Try to detect a recurrence that monotonically increases/decreases from a
2484/// non-zero starting value. These are common as induction variables.
2485static 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;
}
2511}

2513static bool isNonZeroAdd(const APInt &DemandedElts, unsigned Depth,
                       const Query &Q, unsigned BitWidth, Value *X, Value *Y,
                       bool NSW) {
KnownBits XKnown = computeKnownBits(X, DemandedElts, Depth, Q);
KnownBits YKnown = computeKnownBits(Y, 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(Y, DemandedElts, Depth, Q) ||
      isKnownNonZero(X, 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(Y, /*OrZero*/ false, Depth, Q))
  return true;
if (YKnown.isNonNegative() &&
    isKnownToBeAPowerOfTwo(X, /*OrZero*/ false, Depth, Q))
  return true;

return KnownBits::computeForAddSub(/*Add*/ true, NSW, XKnown, YKnown)
    .isNonZero();
2550}

2552static bool isNonZeroSub(const APInt &DemandedElts, unsigned Depth,
                       const Query &Q, unsigned BitWidth, Value *X,
                       Value *Y) {
if (auto *C = dyn_cast<Constant>(X))
  if (C->isNullValue() && isKnownNonZero(Y, DemandedElts, Depth, Q))
    return true;

KnownBits XKnown = computeKnownBits(X, DemandedElts, Depth, Q);
if (XKnown.isUnknown())
  return false;
KnownBits YKnown = computeKnownBits(Y, DemandedElts, Depth, Q);
// If X != Y then X - Y is non zero.
std::optional<bool> ne = KnownBits::ne(XKnown, YKnown);
// If we are unable to compute if X != Y, we won't be able to do anything
// computing the knownbits of the sub expression so just return here.
return ne && *ne;
2568}

2570static bool isNonZeroShift(const Operator *I, const APInt &DemandedElts,
                         unsigned Depth, const Query &Q,
                         const KnownBits &KnownVal) {
auto ShiftOp = [&](const APInt &Lhs, const APInt &Rhs) {
  switch (I->getOpcode()) {
  case Instruction::Shl:
    return Lhs.shl(Rhs);
  case Instruction::LShr:
    return Lhs.lshr(Rhs);
  case Instruction::AShr:
    return Lhs.ashr(Rhs);
  default:
    llvm_unreachable("Unknown Shift Opcode")::llvm::llvm_unreachable_internal("Unknown Shift Opcode", "llvm/lib/Analysis/ValueTracking.cpp"
, 2582);
  }
};

auto InvShiftOp = [&](const APInt &Lhs, const APInt &Rhs) {
  switch (I->getOpcode()) {
  case Instruction::Shl:
    return Lhs.lshr(Rhs);
  case Instruction::LShr:
  case Instruction::AShr:
    return Lhs.shl(Rhs);
  default:
    llvm_unreachable("Unknown Shift Opcode")::llvm::llvm_unreachable_internal("Unknown Shift Opcode", "llvm/lib/Analysis/ValueTracking.cpp"
, 2594);
  }
};

if (KnownVal.isUnknown())
  return false;

KnownBits KnownCnt =
    computeKnownBits(I->getOperand(1), DemandedElts, Depth, Q);
APInt MaxShift = KnownCnt.getMaxValue();
unsigned NumBits = KnownVal.getBitWidth();
if (MaxShift.uge(NumBits))
  return false;

if (!ShiftOp(KnownVal.One, MaxShift).isZero())
  return true;

// If all of the bits shifted out are known to be zero, and Val is known
// non-zero then at least one non-zero bit must remain.
if (InvShiftOp(KnownVal.Zero, NumBits - MaxShift)
        .eq(InvShiftOp(APInt::getAllOnes(NumBits), NumBits - MaxShift)) &&
    isKnownNonZero(I->getOperand(0), DemandedElts, Depth, Q))
  return true;

return false;
2619}

2621/// Return true if the given value is known to be non-zero when defined. For
2622/// vectors, return true if every demanded element is known to be non-zero when
2623/// defined. For pointers, if the context instruction and dominator tree are
2624/// specified, perform context-sensitive analysis and return true if the
2625/// pointer couldn't possibly be null at the specified instruction.
2626/// Supports values with integer or pointer type and vectors of integers.
2627bool isKnownNonZero(const Value *V, const APInt &DemandedElts, unsigned Depth,
                  const Query &Q) {

2630#ifndef NDEBUG
Type *Ty = V->getType();
assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth")(static_cast <bool> (Depth <= MaxAnalysisRecursionDepth
 && "Limit Search Depth") ? void (0) : __assert_fail (
"Depth <= MaxAnalysisRecursionDepth && \"Limit Search Depth\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2632, __extension__ __PRETTY_FUNCTION__
));

if (auto *FVTy = dyn_cast<FixedVectorType>(Ty)) {
  assert((static_cast <bool> (FVTy->getNumElements() == DemandedElts
.getBitWidth() && "DemandedElt width should equal the fixed vector number of elements"
) ? void (0) : __assert_fail ("FVTy->getNumElements() == DemandedElts.getBitWidth() && \"DemandedElt width should equal the fixed vector number of elements\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2637, __extension__ __PRETTY_FUNCTION__
))
      FVTy->getNumElements() == DemandedElts.getBitWidth() &&(static_cast <bool> (FVTy->getNumElements() == DemandedElts
.getBitWidth() && "DemandedElt width should equal the fixed vector number of elements"
) ? void (0) : __assert_fail ("FVTy->getNumElements() == DemandedElts.getBitWidth() && \"DemandedElt width should equal the fixed vector number of elements\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2637, __extension__ __PRETTY_FUNCTION__
))
      "DemandedElt width should equal the fixed vector number of elements")(static_cast <bool> (FVTy->getNumElements() == DemandedElts
.getBitWidth() && "DemandedElt width should equal the fixed vector number of elements"
) ? void (0) : __assert_fail ("FVTy->getNumElements() == DemandedElts.getBitWidth() && \"DemandedElt width should equal the fixed vector number of elements\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2637, __extension__ __PRETTY_FUNCTION__
));
} else {
  assert(DemandedElts == APInt(1, 1) &&(static_cast <bool> (DemandedElts == APInt(1, 1) &&
 "DemandedElt width should be 1 for scalars") ? void (0) : __assert_fail
 ("DemandedElts == APInt(1, 1) && \"DemandedElt width should be 1 for scalars\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2640, __extension__ __PRETTY_FUNCTION__
))
         "DemandedElt width should be 1 for scalars")(static_cast <bool> (DemandedElts == APInt(1, 1) &&
 "DemandedElt width should be 1 for scalars") ? void (0) : __assert_fail
 ("DemandedElts == APInt(1, 1) && \"DemandedElt width should be 1 for scalars\""
, "llvm/lib/Analysis/ValueTracking.cpp", 2640, __extension__ __PRETTY_FUNCTION__
));
}
2642#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: {
  // We need to be a bit careful here. We can only peek through the bitcast
  // if the scalar size of elements in the operand are smaller than and a
  // multiple of the size they are casting too. Take three cases:
  //
  // 1) Unsafe:
  //        bitcast <2 x i16> %NonZero to <4 x i8>
  //
  //    %NonZero can have 2 non-zero i16 elements, but isKnownNonZero on a
  //    <4 x i8> requires that all 4 i8 elements be non-zero which isn't
  //    guranteed (imagine just sign bit set in the 2 i16 elements).
  //
  // 2) Unsafe:
  //        bitcast <4 x i3> %NonZero to <3 x i4>
  //
  //    Even though the scalar size of the src (`i3`) is smaller than the
  //    scalar size of the dst `i4`, because `i3` is not a multiple of `i4`
  //    its possible for the `3 x i4` elements to be zero because there are
  //    some elements in the destination that don't contain any full src
  //    element.
  //
  // 3) Safe:
  //        bitcast <4 x i8> %NonZero to <2 x i16>
  //
  //    This is always safe as non-zero in the 4 i8 elements implies
  //    non-zero in the combination of any two adjacent ones. Since i8 is a
  //    multiple of i16, each i16 is guranteed to have 2 full i8 elements.
  //    This all implies the 2 i16 elements are non-zero.
  Type *FromTy = I->getOperand(0)->getType();
  if ((FromTy->isIntOrIntVectorTy() || FromTy->isPtrOrPtrVectorTy()) &&
      (BitWidth % getBitWidth(FromTy->getScalarType(), Q.DL)) == 0)
    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::Sub:
  return isNonZeroSub(DemandedElts, Depth, Q, BitWidth, I->getOperand(0),
                      I->getOperand(1));
case Instruction::Or:
  // X | Y != 0 if X != 0 or Y != 0.
  return isKnownNonZero(I->getOperand(1), DemandedElts, Depth, Q) ||
         isKnownNonZero(I->getOperand(0), 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 nsw/nuw can't remove any non-zero bits.
  const OverflowingBinaryOperator *BO = cast<OverflowingBinaryOperator>(V);
  if (Q.IIQ.hasNoUnsignedWrap(BO) || Q.IIQ.hasNoSignedWrap(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;

  return isNonZeroShift(I, DemandedElts, Depth, Q, Known);
}
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;

  return isNonZeroShift(I, DemandedElts, Depth, Q, Known);
}
case Instruction::UDiv:
case Instruction::SDiv:
  // X / Y
  // 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);
  if (I->getOpcode() == Instruction::UDiv) {
    std::optional<bool> XUgeY;
    KnownBits XKnown =
        computeKnownBits(I->getOperand(0), DemandedElts, Depth, Q);
    if (!XKnown.isUnknown()) {
      KnownBits YKnown =
          computeKnownBits(I->getOperand(1), DemandedElts, Depth, Q);
      // If X u>= Y then div is non zero (0/0 is UB).
      XUgeY = KnownBits::uge(XKnown, YKnown);
    }
    // If X is total unknown or X u< Y we won't be able to prove non-zero
    // with compute known bits so just return early.
    return XUgeY && *XUgeY;
  }
  break;
case Instruction::Add: {
  // X + Y.

  // If Add has nuw wrap flag, then if either X or Y is non-zero the result is
  // non-zero.
  auto *BO = cast<OverflowingBinaryOperator>(V);
  if (Q.IIQ.hasNoUnsignedWrap(BO))
    return isKnownNonZero(I->getOperand(1), DemandedElts, Depth, Q) ||
           isKnownNonZero(I->getOperand(0), DemandedElts, Depth, Q);

  return isNonZeroAdd(DemandedElts, Depth, Q, BitWidth, I->getOperand(0),
                      I->getOperand(1), Q.IIQ.hasNoSignedWrap(BO));
}
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))
    return isKnownNonZero(I->getOperand(0), DemandedElts, Depth, Q) &&
           isKnownNonZero(I->getOperand(1), DemandedElts, Depth, Q);

  // If either X or Y is odd, then if the other is non-zero the result can't
  // be zero.
  KnownBits XKnown =
      computeKnownBits(I->getOperand(0), DemandedElts, Depth, Q);
  if (XKnown.One[0])
    return isKnownNonZero(I->getOperand(1), DemandedElts, Depth, Q);

  KnownBits YKnown =
      computeKnownBits(I->getOperand(1), DemandedElts, Depth, Q);
  if (YKnown.One[0])
    return XKnown.isNonZero() ||
           isKnownNonZero(I->getOperand(0), DemandedElts, Depth, Q);

  return KnownBits::mul(XKnown, YKnown).isNonZero();
}
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 (auto *II = dyn_cast<IntrinsicInst>(I)) {
    switch (II->getIntrinsicID()) {
    case Intrinsic::sshl_sat:
    case Intrinsic::ushl_sat:
    case Intrinsic::abs:
    case Intrinsic::bitreverse:
    case Intrinsic::bswap:
    case Intrinsic::ctpop:
      return isKnownNonZero(II->getArgOperand(0), DemandedElts, Depth, Q);
    case Intrinsic::ssub_sat:
      return isNonZeroSub(DemandedElts, Depth, Q, BitWidth,
                          II->getArgOperand(0), II->getArgOperand(1));
    case Intrinsic::sadd_sat:
      return isNonZeroAdd(DemandedElts, Depth, Q, BitWidth,
                          II->getArgOperand(0), II->getArgOperand(1),
                          /*NSW*/ true);
    case Intrinsic::umax:
    case Intrinsic::uadd_sat:
      return isKnownNonZero(II->getArgOperand(1), DemandedElts, Depth, Q) ||
             isKnownNonZero(II->getArgOperand(0), DemandedElts, Depth, Q);
    case Intrinsic::smin:
    case Intrinsic::smax: {
      auto KnownOpImpliesNonZero = [&](const KnownBits &K) {
        return II->getIntrinsicID() == Intrinsic::smin
                   ? K.isNegative()
                   : K.isStrictlyPositive();
      };
      KnownBits XKnown =
          computeKnownBits(II->getArgOperand(0), DemandedElts, Depth, Q);
      if (KnownOpImpliesNonZero(XKnown))
        return true;
      KnownBits YKnown =
          computeKnownBits(II->getArgOperand(1), DemandedElts, Depth, Q);
      if (KnownOpImpliesNonZero(YKnown))
        return true;

      if (XKnown.isNonZero() && YKnown.isNonZero())
        return true;
    }
      [[fallthrough]];
    case Intrinsic::umin:
      return isKnownNonZero(II->getArgOperand(0), DemandedElts, Depth, Q) &&
             isKnownNonZero(II->getArgOperand(1), DemandedElts, Depth, Q);
    case Intrinsic::cttz:
      return computeKnownBits(II->getArgOperand(0), DemandedElts, Depth, Q)
          .Zero[0];
    case Intrinsic::ctlz:
      return computeKnownBits(II->getArgOperand(0), DemandedElts, Depth, Q)
          .isNonNegative();
    case Intrinsic::fshr:
    case Intrinsic::fshl:
      // If Op0 == Op1, this is a rotate. rotate(x, y) != 0 iff x != 0.
      if (II->getArgOperand(0) == II->getArgOperand(1))
        return isKnownNonZero(II->getArgOperand(0), DemandedElts, Depth, Q);
      break;
    case Intrinsic::vscale:
      return true;
    default:
      break;
    }
  }
  break;
}

KnownBits Known(BitWidth);
computeKnownBits(V, DemandedElts, Known, Depth, Q);
return Known.One != 0;
2999}

3001bool 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);
3006}

3008/// If the pair of operators are the same invertible function, return the
3009/// the operands of the function corresponding to each input. Otherwise,
3010/// return std::nullopt.  An invertible function is one that is 1-to-1 and maps
3011/// every input value to exactly one output value.  This is equivalent to
3012/// saying that Op1 and Op2 are equal exactly when the specified pair of
3013/// operands are equal, (except that Op1 and Op2 may be poison more often.)
3014static std::optional<std::pair<Value*, Value*>>
3015getInvertibleOperands(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;
3113}

3115/// Return true if V2 == V1 + X, where X is known non-zero.
3116static 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);
3129}

3131/// Return true if V2 == V1 * C, where V1 is known non-zero, C is not 0/1 and
3132/// the multiplication is nuw or nsw.
3133static 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;
3142}

3144/// Return true if V2 == V1 << C, where V1 is known non-zero, C is not 0 and
3145/// the shift is nuw or nsw.
3146static 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;
3155}

3157static 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;
3185}

3187/// Return true if it is known that V1 != V2.
3188static 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;
3237}

3239/// Return true if 'V & Mask' is known to be zero.  We use this predicate to
3240/// simplify operations downstream. Mask is known to be zero for bits that V
3241/// cannot have.
3242///
3243/// This function is defined on values with integer type, values with pointer
3244/// type, and vectors of integers.  In the case
3245/// where V is a vector, the mask, known zero, and known one values are the
3246/// same width as the vector element, and the bit is set only if it is true
3247/// for all of the elements in the vector.
3248bool 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);
3253}

3255// Match a signed min+max clamp pattern like smax(smin(In, CHigh), CLow).
3256// Returns the input and lower/upper bounds.
3257static bool isSignedMinMaxClamp(const Value *Select, const Value *&In,
                              const APInt *&CLow, const APInt *&CHigh) {
assert(isa<Operator>(Select) &&(static_cast <bool> (isa<Operator>(Select) &&
 cast<Operator>(Select)->getOpcode() == Instruction::
Select && "Input should be a Select!") ? void (0) : __assert_fail
 ("isa<Operator>(Select) && cast<Operator>(Select)->getOpcode() == Instruction::Select && \"Input should be a Select!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3261, __extension__ __PRETTY_FUNCTION__
))
       cast<Operator>(Select)->getOpcode() == Instruction::Select &&(static_cast <bool> (isa<Operator>(Select) &&
 cast<Operator>(Select)->getOpcode() == Instruction::
Select && "Input should be a Select!") ? void (0) : __assert_fail
 ("isa<Operator>(Select) && cast<Operator>(Select)->getOpcode() == Instruction::Select && \"Input should be a Select!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3261, __extension__ __PRETTY_FUNCTION__
))
       "Input should be a Select!")(static_cast <bool> (isa<Operator>(Select) &&
 cast<Operator>(Select)->getOpcode() == Instruction::
Select && "Input should be a Select!") ? void (0) : __assert_fail
 ("isa<Operator>(Select) && cast<Operator>(Select)->getOpcode() == Instruction::Select && \"Input should be a Select!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3261, __extension__ __PRETTY_FUNCTION__
));

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);
3284}

3286static bool isSignedMinMaxIntrinsicClamp(const IntrinsicInst *II,
                                       const APInt *&CLow,
                                       const APInt *&CHigh) {
assert((II->getIntrinsicID() == Intrinsic::smin ||(static_cast <bool> ((II->getIntrinsicID() == Intrinsic
::smin || II->getIntrinsicID() == Intrinsic::smax) &&
 "Must be smin/smax") ? void (0) : __assert_fail ("(II->getIntrinsicID() == Intrinsic::smin || II->getIntrinsicID() == Intrinsic::smax) && \"Must be smin/smax\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3290, __extension__ __PRETTY_FUNCTION__
))
        II->getIntrinsicID() == Intrinsic::smax) && "Must be smin/smax")(static_cast <bool> ((II->getIntrinsicID() == Intrinsic
::smin || II->getIntrinsicID() == Intrinsic::smax) &&
 "Must be smin/smax") ? void (0) : __assert_fail ("(II->getIntrinsicID() == Intrinsic::smin || II->getIntrinsicID() == Intrinsic::smax) && \"Must be smin/smax\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3290, __extension__ __PRETTY_FUNCTION__
));

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);
3302}

3304/// For vector constants, loop over the elements and find the constant with the
3305/// minimum number of sign bits. Return 0 if the value is not a vector constant
3306/// or if any element was not analyzed; otherwise, return the count for the
3307/// element with the minimum number of sign bits.
3308static 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;
3329}

3331static unsigned ComputeNumSignBitsImpl(const Value *V,
                                     const APInt &DemandedElts,
                                     unsigned Depth, const Query &Q);

3335static 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!")(static_cast <bool> (Result > 0 && "At least one sign bit needs to be present!"
) ? void (0) : __assert_fail ("Result > 0 && \"At least one sign bit needs to be present!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3338, __extension__ __PRETTY_FUNCTION__
));
return Result;
3340}

3342/// Return the number of times the sign bit of the register is replicated into
3343/// the other bits. We know that at least 1 bit is always equal to the sign bit
3344/// (itself), but other cases can give us information. For example, immediately
3345/// after an "ashr X, 2", we know that the top 3 bits are all equal to each
3346/// other, so we return 3. For vectors, return the number of sign bits for the
3347/// vector element with the minimum number of known sign bits of the demanded
3348/// elements in the vector specified by DemandedElts.
3349static unsigned ComputeNumSignBitsImpl(const Value *V,
                                     const APInt &DemandedElts,
                                     unsigned Depth, const Query &Q) {
Type *Ty = V->getType();
3353#ifndef NDEBUG
assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth")(static_cast <bool> (Depth <= MaxAnalysisRecursionDepth
 && "Limit Search Depth") ? void (0) : __assert_fail (
"Depth <= MaxAnalysisRecursionDepth && \"Limit Search Depth\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3354, __extension__ __PRETTY_FUNCTION__
));

if (auto *FVTy = dyn_cast<FixedVectorType>(Ty)) {
  assert((static_cast <bool> (FVTy->getNumElements() == DemandedElts
.getBitWidth() && "DemandedElt width should equal the fixed vector number of elements"
) ? void (0) : __assert_fail ("FVTy->getNumElements() == DemandedElts.getBitWidth() && \"DemandedElt width should equal the fixed vector number of elements\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3359, __extension__ __PRETTY_FUNCTION__
))
      FVTy->getNumElements() == DemandedElts.getBitWidth() &&(static_cast <bool> (FVTy->getNumElements() == DemandedElts
.getBitWidth() && "DemandedElt width should equal the fixed vector number of elements"
) ? void (0) : __assert_fail ("FVTy->getNumElements() == DemandedElts.getBitWidth() && \"DemandedElt width should equal the fixed vector number of elements\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3359, __extension__ __PRETTY_FUNCTION__
))
      "DemandedElt width should equal the fixed vector number of elements")(static_cast <bool> (FVTy->getNumElements() == DemandedElts
.getBitWidth() && "DemandedElt width should equal the fixed vector number of elements"
) ? void (0) : __assert_fail ("FVTy->getNumElements() == DemandedElts.getBitWidth() && \"DemandedElt width should equal the fixed vector number of elements\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3359, __extension__ __PRETTY_FUNCTION__
));
} else {
  assert(DemandedElts == APInt(1, 1) &&(static_cast <bool> (DemandedElts == APInt(1, 1) &&
 "DemandedElt width should be 1 for scalars") ? void (0) : __assert_fail
 ("DemandedElts == APInt(1, 1) && \"DemandedElt width should be 1 for scalars\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3362, __extension__ __PRETTY_FUNCTION__
))
         "DemandedElt width should be 1 for scalars")(static_cast <bool> (DemandedElts == APInt(1, 1) &&
 "DemandedElt width should be 1 for scalars") ? void (0) : __assert_fail
 ("DemandedElts == APInt(1, 1) && \"DemandedElt width should be 1 for scalars\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3362, __extension__ __PRETTY_FUNCTION__
));
}
3364#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")(static_cast <bool> (Tmp <= TyBits && "Failed to determine minimum sign bits"
) ? void (0) : __assert_fail ("Tmp <= TyBits && \"Failed to determine minimum sign bits\""
, "llvm/lib/Analysis/ValueTracking.cpp", 3632, __extension__ __PRETTY_FUNCTION__
));
    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());
3672}

3674Intrinsic::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;
3777}

3779/// Return true if we can prove that the specified FP value is never equal to
3780/// -0.0.
3781/// NOTE: Do not check 'nsz' here because that fast-math-flag does not guarantee
3782///       that a value is not -0.0. It only guarantees that -0.0 may be treated
3783///       the same as +0.0 in floating-point ops.
3784bool 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;
3832}

3834/// If \p SignBitOnly is true, test for a known 0 sign bit rather than a
3835/// standard ordered compare. e.g. make -0.0 olt 0.0 be true because of the sign
3836/// bit despite comparing equal.
3837static 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;
4021}

4023bool llvm::CannotBeOrderedLessThanZero(const Value *V,
                                     const TargetLibraryInfo *TLI) {
return cannotBeOrderedLessThanZeroImpl(V, TLI, false, 0);
4026}

4028bool llvm::SignBitMustBeZero(const Value *V, const TargetLibraryInfo *TLI) {
return cannotBeOrderedLessThanZeroImpl(V, TLI, true, 0);
4030}

4032bool llvm::isKnownNeverInfinity(const Value *V, const TargetLibraryInfo *TLI,
                              unsigned Depth) {
assert(V->getType()->isFPOrFPVectorTy() && "Querying for Inf on non-FP type")(static_cast <bool> (V->getType()->isFPOrFPVectorTy
() && "Querying for Inf on non-FP type") ? void (0) :
 __assert_fail ("V->getType()->isFPOrFPVectorTy() && \"Querying for Inf on non-FP type\""
, "llvm/lib/Analysis/ValueTracking.cpp", 4034, __extension__ __PRETTY_FUNCTION__
));

// 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;

if (const auto *Arg = dyn_cast<Argument>(V)) {
  if ((Arg->getNoFPClass() & fcInf) == fcInf)
    return true;
}

// TODO: Use fpclass like API for isKnown queries and distinguish +inf from
// -inf.
if (const auto *CB = dyn_cast<CallBase>(V)) {
  if ((CB->getRetNoFPClass() & fcInf) == fcInf)
    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;
4170}

4172bool llvm::isKnownNeverNaN(const Value *V, const TargetLibraryInfo *TLI,
                         unsigned Depth) {
assert(V->getType()->isFPOrFPVectorTy() && "Querying for NaN on non-FP type")(static_cast <bool> (V->getType()->isFPOrFPVectorTy
() && "Querying for NaN on non-FP type") ? void (0) :
 __assert_fail ("V->getType()->isFPOrFPVectorTy() && \"Querying for NaN on non-FP type\""
, "llvm/lib/Analysis/ValueTracking.cpp", 4174, __extension__ __PRETTY_FUNCTION__
));

// 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;

if (const auto *Arg = dyn_cast<Argument>(V)) {
  if ((Arg->getNoFPClass() & fcNan) == fcNan)
    return true;
}

// TODO: Use fpclass like API for isKnown queries and distinguish snan from
// qnan.
if (const auto *CB = dyn_cast<CallBase>(V)) {
  FPClassTest Mask = CB->getRetNoFPClass();
  if ((Mask & fcNan) == fcNan)
    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;
4290}

4292/// Return true if it's possible to assume IEEE treatment of input denormals in
4293/// \p F for \p Val.
4294static bool inputDenormalIsIEEE(const Function &F, const Type *Ty) {
Ty = Ty->getScalarType();
return F.getDenormalMode(Ty->getFltSemantics()).Input == DenormalMode::IEEE;
4297}

4299bool KnownFPClass::isKnownNeverLogicalZero(const Function &F, Type *Ty) const {
return isKnownNeverZero() &&
       (isKnownNeverSubnormal() || inputDenormalIsIEEE(F, Ty));
4302}

4304/// Returns a pair of values, which if passed to llvm.is.fpclass, returns the
4305/// same result as an fcmp with the given operands.
4306std::pair<Value *, FPClassTest> llvm::fcmpToClassTest(FCmpInst::Predicate Pred,
                                                    const Function &F,
                                                    Value *LHS, Value *RHS,
                                                    bool LookThroughSrc) {
const APFloat *ConstRHS;
if (!match(RHS, m_APFloat(ConstRHS)))
  return {nullptr, fcNone};

if (ConstRHS->isZero()) {
  // Compares with fcNone are only exactly equal to fcZero if input denormals
  // are not flushed.
  // TODO: Handle DAZ by expanding masks to cover subnormal cases.
  if (Pred != FCmpInst::FCMP_ORD && Pred != FCmpInst::FCMP_UNO &&
      !inputDenormalIsIEEE(F, LHS->getType()))
    return {nullptr, fcNone};

  switch (Pred) {
  case FCmpInst::FCMP_OEQ: // Match x == 0.0
    return {LHS, fcZero};
  case FCmpInst::FCMP_UEQ: // Match isnan(x) || (x == 0.0)
    return {LHS, fcZero | fcNan};
  case FCmpInst::FCMP_UNE: // Match (x != 0.0)
    return {LHS, ~fcZero};
  case FCmpInst::FCMP_ONE: // Match !isnan(x) && x != 0.0
    return {LHS, ~fcNan & ~fcZero};
  case FCmpInst::FCMP_ORD:
    // Canonical form of ord/uno is with a zero. We could also handle
    // non-canonical other non-NaN constants or LHS == RHS.
    return {LHS, ~fcNan};
  case FCmpInst::FCMP_UNO:
    return {LHS, fcNan};
  case FCmpInst::FCMP_OGT: // x > 0
    return {LHS, fcPosSubnormal | fcPosNormal | fcPosInf};
  case FCmpInst::FCMP_UGT: // isnan(x) || x > 0
    return {LHS, fcPosSubnormal | fcPosNormal | fcPosInf | fcNan};
  case FCmpInst::FCMP_OGE: // x >= 0
    return {LHS, fcPositive | fcNegZero};
  case FCmpInst::FCMP_UGE: // isnan(x) || x >= 0
    return {LHS, fcPositive | fcNegZero | fcNan};
  case FCmpInst::FCMP_OLT: // x < 0
    return {LHS, fcNegSubnormal | fcNegNormal | fcNegInf};
  case FCmpInst::FCMP_ULT: // isnan(x) || x < 0
    return {LHS, fcNegSubnormal | fcNegNormal | fcNegInf | fcNan};
  case FCmpInst::FCMP_OLE: // x <= 0
    return {LHS, fcNegative | fcPosZero};
  case FCmpInst::FCMP_ULE: // isnan(x) || x <= 0
    return {LHS, fcNegative | fcPosZero | fcNan};
  default:
    break;
  }

  return {nullptr, fcNone};
}

Value *Src = LHS;
const bool IsFabs = LookThroughSrc && match(LHS, m_FAbs(m_Value(Src)));

// Compute the test mask that would return true for the ordered comparisons.
FPClassTest Mask;

if (ConstRHS->isInfinity()) {
  switch (Pred) {
  case FCmpInst::FCMP_OEQ:
  case FCmpInst::FCMP_UNE: {
    // Match __builtin_isinf patterns
    //
    //   fcmp oeq x, +inf -> is_fpclass x, fcPosInf
    //   fcmp oeq fabs(x), +inf -> is_fpclass x, fcInf
    //   fcmp oeq x, -inf -> is_fpclass x, fcNegInf
    //   fcmp oeq fabs(x), -inf -> is_fpclass x, 0 -> false
    //
    //   fcmp une x, +inf -> is_fpclass x, ~fcPosInf
    //   fcmp une fabs(x), +inf -> is_fpclass x, ~fcInf
    //   fcmp une x, -inf -> is_fpclass x, ~fcNegInf
    //   fcmp une fabs(x), -inf -> is_fpclass x, fcAllFlags -> true

    if (ConstRHS->isNegative()) {
      Mask = fcNegInf;
      if (IsFabs)
        Mask = fcNone;
    } else {
      Mask = fcPosInf;
      if (IsFabs)
        Mask |= fcNegInf;
    }

    break;
  }
  case FCmpInst::FCMP_ONE:
  case FCmpInst::FCMP_UEQ: {
    // Match __builtin_isinf patterns
    //   fcmp one x, -inf -> is_fpclass x, fcNegInf
    //   fcmp one fabs(x), -inf -> is_fpclass x, ~fcNegInf & ~fcNan
    //   fcmp one x, +inf -> is_fpclass x, ~fcNegInf & ~fcNan
    //   fcmp one fabs(x), +inf -> is_fpclass x, ~fcInf & fcNan
    //
    //   fcmp ueq x, +inf -> is_fpclass x, fcPosInf|fcNan
    //   fcmp ueq (fabs x), +inf -> is_fpclass x, fcInf|fcNan
    //   fcmp ueq x, -inf -> is_fpclass x, fcNegInf|fcNan
    //   fcmp ueq fabs(x), -inf -> is_fpclass x, fcNan
    if (ConstRHS->isNegative()) {
      Mask = ~fcNegInf & ~fcNan;
      if (IsFabs)
        Mask = ~fcNan;
    } else {
      Mask = ~fcPosInf & ~fcNan;
      if (IsFabs)
        Mask &= ~fcNegInf;
    }

    break;
  }
  case FCmpInst::FCMP_OLT:
  case FCmpInst::FCMP_UGE: {
    if (ConstRHS->isNegative()) // TODO
      return {nullptr, fcNone};

    // fcmp olt fabs(x), +inf -> fcFinite
    // fcmp uge fabs(x), +inf -> ~fcFinite
    // fcmp olt x, +inf -> fcFinite|fcNegInf
    // fcmp uge x, +inf -> ~(fcFinite|fcNegInf)
    Mask = fcFinite;
    if (!IsFabs)
      Mask |= fcNegInf;
    break;
  }
  case FCmpInst::FCMP_OGE:
  case FCmpInst::FCMP_ULT: {
    if (ConstRHS->isNegative()) // TODO
      return {nullptr, fcNone};

    // fcmp oge fabs(x), +inf -> fcInf
    // fcmp oge x, +inf -> fcPosInf
    // fcmp ult fabs(x), +inf -> ~fcInf
    // fcmp ult x, +inf -> ~fcPosInf
    Mask = fcPosInf;
    if (IsFabs)
      Mask |= fcNegInf;
    break;
  }
  default:
    return {nullptr, fcNone};
  }
} else if (ConstRHS->isSmallestNormalized() && !ConstRHS->isNegative()) {
  // Match pattern that's used in __builtin_isnormal.
  switch (Pred) {
  case FCmpInst::FCMP_OLT:
  case FCmpInst::FCMP_UGE: {
    // fcmp olt x, smallest_normal -> fcNegInf|fcNegNormal|fcSubnormal|fcZero
    // fcmp olt fabs(x), smallest_normal -> fcSubnormal|fcZero
    // fcmp uge x, smallest_normal -> fcNan|fcPosNormal|fcPosInf
    // fcmp uge fabs(x), smallest_normal -> ~(fcSubnormal|fcZero)
    Mask = fcZero | fcSubnormal;
    if (!IsFabs)
      Mask |= fcNegNormal | fcNegInf;

    break;
  }
  case FCmpInst::FCMP_OGE:
  case FCmpInst::FCMP_ULT: {
    // fcmp oge x, smallest_normal -> fcPosNormal | fcPosInf
    // fcmp oge fabs(x), smallest_normal -> fcInf | fcNormal
    // fcmp ult x, smallest_normal -> ~(fcPosNormal | fcPosInf)
    // fcmp ult fabs(x), smallest_normal -> ~(fcInf | fcNormal)
    Mask = fcPosInf | fcPosNormal;
    if (IsFabs)
      Mask |= fcNegInf | fcNegNormal;
    break;
  }
  default:
    return {nullptr, fcNone};
  }
} else
  return {nullptr, fcNone};

// Invert the comparison for the unordered cases.
if (FCmpInst::isUnordered(Pred))
  Mask = ~Mask;

return {Src, Mask};
4486}

4488static FPClassTest computeKnownFPClassFromAssumes(const Value *V,
                                                const Query &Q) {
FPClassTest KnownFromAssume = fcAllFlags;

// Try to restrict the floating-point classes based on information from
// assumptions.
for (auto &AssumeVH : Q.AC->assumptionsFor(V)) {
  if (!AssumeVH)
    continue;
  CallInst *I = cast<CallInst>(AssumeVH);
  const Function *F = I->getFunction();

  assert(F == Q.CxtI->getParent()->getParent() &&(static_cast <bool> (F == Q.CxtI->getParent()->getParent
() && "Got assumption for the wrong function!") ? void
 (0) : __assert_fail ("F == Q.CxtI->getParent()->getParent() && \"Got assumption for the wrong function!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 4501, __extension__ __PRETTY_FUNCTION__
))
         "Got assumption for the wrong function!")(static_cast <bool> (F == Q.CxtI->getParent()->getParent
() && "Got assumption for the wrong function!") ? void
 (0) : __assert_fail ("F == Q.CxtI->getParent()->getParent() && \"Got assumption for the wrong function!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 4501, __extension__ __PRETTY_FUNCTION__
));
  assert(I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume &&(static_cast <bool> (I->getCalledFunction()->getIntrinsicID
() == Intrinsic::assume && "must be an assume intrinsic"
) ? void (0) : __assert_fail ("I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume && \"must be an assume intrinsic\""
, "llvm/lib/Analysis/ValueTracking.cpp", 4503, __extension__ __PRETTY_FUNCTION__
))
         "must be an assume intrinsic")(static_cast <bool> (I->getCalledFunction()->getIntrinsicID
() == Intrinsic::assume && "must be an assume intrinsic"
) ? void (0) : __assert_fail ("I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume && \"must be an assume intrinsic\""
, "llvm/lib/Analysis/ValueTracking.cpp", 4503, __extension__ __PRETTY_FUNCTION__
));

  if (!isValidAssumeForContext(I, Q.CxtI, Q.DT))
    continue;

  CmpInst::Predicate Pred;
  Value *LHS, *RHS;
  uint64_t ClassVal = 0;
  if (match(I->getArgOperand(0), m_FCmp(Pred, m_Value(LHS), m_Value(RHS)))) {
    auto [TestedValue, TestedMask] =
        fcmpToClassTest(Pred, *F, LHS, RHS, true);
    // First see if we can fold in fabs/fneg into the test.
    if (TestedValue == V)
      KnownFromAssume &= TestedMask;
    else {
      // Try again without the lookthrough if we found a different source
      // value.
      auto [TestedValue, TestedMask] =
          fcmpToClassTest(Pred, *F, LHS, RHS, false);
      if (TestedValue == V)
        KnownFromAssume &= TestedMask;
    }
  } else if (match(I->getArgOperand(0),
                   m_Intrinsic<Intrinsic::is_fpclass>(
                       m_Value(LHS), m_ConstantInt(ClassVal)))) {
    KnownFromAssume &= static_cast<FPClassTest>(ClassVal);
  }
}

return KnownFromAssume;
4533}

4535void computeKnownFPClass(const Value *V, const APInt &DemandedElts,
                       FPClassTest InterestedClasses, KnownFPClass &Known,
                       unsigned Depth, const Query &Q,
                       const TargetLibraryInfo *TLI);

4540static void computeKnownFPClass(const Value *V, KnownFPClass &Known,
                              FPClassTest InterestedClasses, unsigned Depth,
                              const Query &Q, const TargetLibraryInfo *TLI) {
auto *FVTy = dyn_cast<FixedVectorType>(V->getType());
APInt DemandedElts =
    FVTy ? APInt::getAllOnes(FVTy->getNumElements()) : APInt(1, 1);
computeKnownFPClass(V, DemandedElts, InterestedClasses, Known, Depth, Q, TLI);
4547}

4549static void computeKnownFPClassForFPTrunc(const Operator *Op,
                                        const APInt &DemandedElts,
                                        FPClassTest InterestedClasses,
                                        KnownFPClass &Known, unsigned Depth,
                                        const Query &Q,
                                        const TargetLibraryInfo *TLI) {
if ((InterestedClasses & fcNan) == fcNone)
  return;

KnownFPClass KnownSrc;
computeKnownFPClass(Op->getOperand(0), DemandedElts, InterestedClasses,
                    KnownSrc, Depth + 1, Q, TLI);
if (KnownSrc.isKnownNeverNaN())
  Known.knownNot(fcNan);

// Infinity needs a range check.
// TODO: Sign bit should be preserved
4566}

4568// TODO: Merge implementations of isKnownNeverNaN, isKnownNeverInfinity,
4569// CannotBeNegativeZero, cannotBeOrderedLessThanZero into here.

4571void computeKnownFPClass(const Value *V, const APInt &DemandedElts,
                       FPClassTest InterestedClasses, KnownFPClass &Known,
                       unsigned Depth, const Query &Q,
                       const TargetLibraryInfo *TLI) {
assert(Known.isUnknown() && "should not be called with known information")(static_cast <bool> (Known.isUnknown() && "should not be called with known information"
) ? void (0) : __assert_fail ("Known.isUnknown() && \"should not be called with known information\""
, "llvm/lib/Analysis/ValueTracking.cpp", 4575, __extension__ __PRETTY_FUNCTION__
));

if (!DemandedElts) {
  // No demanded elts, better to assume we don't know anything.
  Known.resetAll();
  return;
}

assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth")(static_cast <bool> (Depth <= MaxAnalysisRecursionDepth
 && "Limit Search Depth") ? void (0) : __assert_fail (
"Depth <= MaxAnalysisRecursionDepth && \"Limit Search Depth\""
, "llvm/lib/Analysis/ValueTracking.cpp", 4583, __extension__ __PRETTY_FUNCTION__
));

if (auto *CFP = dyn_cast_or_null<ConstantFP>(V)) {
  Known.KnownFPClasses = CFP->getValueAPF().classify();
  Known.SignBit = CFP->isNegative();
  return;
}

// Try to handle fixed width vector constants
auto *VFVTy = dyn_cast<FixedVectorType>(V->getType());
const Constant *CV = dyn_cast<Constant>(V);
if (VFVTy && CV) {
  Known.KnownFPClasses = fcNone;

  // For vectors, verify that each element is not NaN.
  unsigned NumElts = VFVTy->getNumElements();
  for (unsigned i = 0; i != NumElts; ++i) {
    Constant *Elt = CV->getAggregateElement(i);
    if (!Elt) {
      Known = KnownFPClass();
      return;
    }
    if (isa<UndefValue>(Elt))
      continue;
    auto *CElt = dyn_cast<ConstantFP>(Elt);
    if (!CElt) {
      Known = KnownFPClass();
      return;
    }

    KnownFPClass KnownElt{CElt->getValueAPF().classify(), CElt->isNegative()};
    Known |= KnownElt;
  }

  return;
}

FPClassTest KnownNotFromFlags = fcNone;
if (const auto *CB = dyn_cast<CallBase>(V))
  KnownNotFromFlags |= CB->getRetNoFPClass();
else if (const auto *Arg = dyn_cast<Argument>(V))
  KnownNotFromFlags |= Arg->getNoFPClass();

const Operator *Op = dyn_cast<Operator>(V);
if (const FPMathOperator *FPOp = dyn_cast_or_null<FPMathOperator>(Op)) {
  if (FPOp->hasNoNaNs())
    KnownNotFromFlags |= fcNan;
  if (FPOp->hasNoInfs())
    KnownNotFromFlags |= fcInf;
}

if (Q.AC) {
  FPClassTest AssumedClasses = computeKnownFPClassFromAssumes(V, Q);
  KnownNotFromFlags |= ~AssumedClasses;
}

// We no longer need to find out about these bits from inputs if we can
// assume this from flags/attributes.
InterestedClasses &= ~KnownNotFromFlags;

auto ClearClassesFromFlags = make_scope_exit([=, &Known] {
  Known.knownNot(KnownNotFromFlags);
});

if (!Op)
  return;

// All recursive calls that increase depth must come after this.
if (Depth == MaxAnalysisRecursionDepth)
  return;

const unsigned Opc = Op->getOpcode();
switch (Opc) {
case Instruction::FNeg: {
  computeKnownFPClass(Op->getOperand(0), DemandedElts, InterestedClasses,
                      Known, Depth + 1, Q, TLI);
  Known.fneg();
  break;
}
case Instruction::Select: {
  KnownFPClass Known2;
  computeKnownFPClass(Op->getOperand(1), DemandedElts, InterestedClasses,
                      Known, Depth + 1, Q, TLI);
  computeKnownFPClass(Op->getOperand(2), DemandedElts, InterestedClasses,
                      Known2, Depth + 1, Q, TLI);
  Known |= Known2;
  break;
}
case Instruction::Call: {
  if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op)) {
    const Intrinsic::ID IID = II->getIntrinsicID();
    switch (IID) {
    case Intrinsic::fabs: {
      if ((InterestedClasses & (fcNan | fcPositive)) != fcNone) {
        // If we only care about the sign bit we don't need to inspect the
        // operand.
        computeKnownFPClass(II->getArgOperand(0), DemandedElts,
                            InterestedClasses, Known, Depth + 1, Q, TLI);
      }

      Known.fabs();
      break;
    }
    case Intrinsic::copysign: {
      KnownFPClass KnownSign;

      computeKnownFPClass(II->getArgOperand(0), DemandedElts,
                          InterestedClasses, Known, Depth + 1, Q, TLI);
      computeKnownFPClass(II->getArgOperand(1), DemandedElts,
                          InterestedClasses, KnownSign, Depth + 1, Q, TLI);
      Known.copysign(KnownSign);
      break;
    }
    case Intrinsic::fma:
    case Intrinsic::fmuladd: {
      if ((InterestedClasses & fcNegative) == fcNone)
        break;

      if (II->getArgOperand(0) != II->getArgOperand(1))
        break;

      // The multiply cannot be -0 and therefore the add can't be -0
      Known.knownNot(fcNegZero);

      // x * x + y is non-negative if y is non-negative.
      KnownFPClass KnownAddend;
      computeKnownFPClass(II->getArgOperand(2), DemandedElts,
                          InterestedClasses, KnownAddend, Depth + 1, Q, TLI);

      // TODO: Known sign bit with no nans
      if (KnownAddend.cannotBeOrderedLessThanZero())
        Known.knownNot(fcNegative);
      break;
    }
    case Intrinsic::sin:
    case Intrinsic::cos: {
      // Return NaN on infinite inputs.
      KnownFPClass KnownSrc;
      computeKnownFPClass(II->getArgOperand(0), DemandedElts,
                          InterestedClasses, KnownSrc, Depth + 1, Q, TLI);
      Known.knownNot(fcInf);
      if (KnownSrc.isKnownNeverNaN() && KnownSrc.isKnownNeverInfinity())
        Known.knownNot(fcNan);
      break;
    }

    case Intrinsic::maxnum:
    case Intrinsic::minnum:
    case Intrinsic::minimum:
    case Intrinsic::maximum: {
      KnownFPClass KnownLHS, KnownRHS;
      computeKnownFPClass(II->getArgOperand(0), DemandedElts,
                          InterestedClasses, KnownLHS, Depth + 1, Q, TLI);
      computeKnownFPClass(II->getArgOperand(1), DemandedElts,
                          InterestedClasses, KnownRHS, Depth + 1, Q, TLI);

      bool NeverNaN =
          KnownLHS.isKnownNeverNaN() || KnownRHS.isKnownNeverNaN();
      Known = KnownLHS | KnownRHS;

      // If either operand is not NaN, the result is not NaN.
      if (NeverNaN && (IID == Intrinsic::minnum || IID == Intrinsic::maxnum))
        Known.knownNot(fcNan);

      if (IID == Intrinsic::maxnum) {
        // If at least one operand is known to be positive, the result must be
        // positive.
        if ((KnownLHS.cannotBeOrderedLessThanZero() &&
             KnownLHS.isKnownNeverNaN()) ||
            (KnownRHS.cannotBeOrderedLessThanZero() &&
             KnownRHS.isKnownNeverNaN()))
          Known.knownNot(KnownFPClass::OrderedLessThanZeroMask);
      } else if (IID == Intrinsic::maximum) {
        // If at least one operand is known to be positive, the result must be
        // positive.
        if (KnownLHS.cannotBeOrderedLessThanZero() ||
            KnownRHS.cannotBeOrderedLessThanZero())
          Known.knownNot(KnownFPClass::OrderedLessThanZeroMask);
      } else if (IID == Intrinsic::minnum) {
        // If at least one operand is known to be negative, the result must be
        // negative.
        if ((KnownLHS.cannotBeOrderedGreaterThanZero() &&
             KnownLHS.isKnownNeverNaN()) ||
            (KnownRHS.cannotBeOrderedGreaterThanZero() &&
             KnownRHS.isKnownNeverNaN()))
          Known.knownNot(KnownFPClass::OrderedGreaterThanZeroMask);
      } else {
        // If at least one operand is known to be negative, the result must be
        // negative.
        if (KnownLHS.cannotBeOrderedGreaterThanZero() ||
            KnownRHS.cannotBeOrderedGreaterThanZero())
          Known.knownNot(KnownFPClass::OrderedGreaterThanZeroMask);
        }

      // Fixup zero handling if denormals could be returned as a zero.
      //
      // As there's no spec for denormal flushing, be conservative with the
      // treatment of denormals that could be flushed to zero. For older
      // subtargets on AMDGPU the min/max instructions would not flush the
      // output and return the original value.
      //
      // TODO: This could be refined based on the sign
      if ((Known.KnownFPClasses & fcZero) != fcNone &&
          !Known.isKnownNeverSubnormal()) {
        const Function *Parent = II->getFunction();
        DenormalMode Mode = Parent->getDenormalMode(
            II->getType()->getScalarType()->getFltSemantics());
        if (Mode != DenormalMode::getIEEE())
          Known.KnownFPClasses |= fcZero;
      }

      break;
    }
    case Intrinsic::canonicalize: {
      computeKnownFPClass(II->getArgOperand(0), DemandedElts,
                          InterestedClasses, Known, Depth + 1, Q, TLI);
      // Canonicalize is guaranteed to quiet signaling nans.
      Known.knownNot(fcSNan);

      // If the parent function flushes denormals, the canonical output cannot
      // be a denormal.
      const fltSemantics &FPType = II->getType()->getFltSemantics();
      DenormalMode DenormMode = II->getFunction()->getDenormalMode(FPType);
      if (DenormMode.inputsAreZero() || DenormMode.outputsAreZero())
        Known.knownNot(fcSubnormal);

      if (DenormMode.Input == DenormalMode::PositiveZero ||
          (DenormMode.Output == DenormalMode::PositiveZero &&
           DenormMode.Input == DenormalMode::IEEE))
        Known.knownNot(fcNegZero);

      break;
    }
    case Intrinsic::trunc: {
      KnownFPClass KnownSrc;

      FPClassTest InterestedSrcs = InterestedClasses;
      if (InterestedClasses & fcZero)
        InterestedClasses |= fcNormal | fcSubnormal;

      computeKnownFPClass(II->getArgOperand(0), DemandedElts, InterestedSrcs,
                          KnownSrc, Depth + 1, Q, TLI);

      // Integer results cannot be subnormal.
      Known.knownNot(fcSubnormal);

      // trunc passes through infinities.
      if (KnownSrc.isKnownNeverPosInfinity())
        Known.knownNot(fcPosInf);
      if (KnownSrc.isKnownNeverNegInfinity())
        Known.knownNot(fcNegInf);

      // Non-constrained intrinsics do not guarantee signaling nan quieting.
      if (KnownSrc.isKnownNeverNaN())
        Known.knownNot(fcNan);

      if (KnownSrc.isKnownNever(fcPosNormal))
        Known.knownNot(fcPosNormal);

      if (KnownSrc.isKnownNever(fcNegNormal))
        Known.knownNot(fcNegNormal);

      if (KnownSrc.isKnownNever(fcPosZero | fcPosSubnormal | fcPosNormal))
        Known.knownNot(fcPosZero);

      if (KnownSrc.isKnownNever(fcNegZero | fcNegSubnormal | fcNegNormal))
        Known.knownNot(fcNegZero);

      // Sign should be preserved
      Known.SignBit = KnownSrc.SignBit;
      break;
    }
    case Intrinsic::exp:
    case Intrinsic::exp2: {
      Known.knownNot(fcNegative);
      if ((InterestedClasses & fcNan) == fcNone)
        break;

      KnownFPClass KnownSrc;
      computeKnownFPClass(II->getArgOperand(0), DemandedElts,
                          InterestedClasses, KnownSrc, Depth + 1, Q, TLI);
      if (KnownSrc.isKnownNeverNaN()) {
        Known.knownNot(fcNan);
        Known.SignBit = false;
      }

      break;
    }
    case Intrinsic::fptrunc_round: {
      computeKnownFPClassForFPTrunc(Op, DemandedElts, InterestedClasses,
                                    Known, Depth, Q, TLI);
      break;
    }
    case Intrinsic::log:
    case Intrinsic::log10:
    case Intrinsic::log2:
    case Intrinsic::experimental_constrained_log:
    case Intrinsic::experimental_constrained_log10:
    case Intrinsic::experimental_constrained_log2: {
      // log(+inf) -> +inf
      // log([+-]0.0) -> -inf
      // log(-inf) -> nan
      // log(-x) -> nan
      if ((InterestedClasses & (fcNan | fcInf)) == fcNone)
        break;

      FPClassTest InterestedSrcs = InterestedClasses;
      if ((InterestedClasses & fcNegInf) != fcNone)
        InterestedSrcs |= fcZero | fcSubnormal;
      if ((InterestedClasses & fcNan) != fcNone)
        InterestedSrcs |= fcNan | (fcNegative & ~fcNan);

      KnownFPClass KnownSrc;
      computeKnownFPClass(II->getArgOperand(0), DemandedElts, InterestedSrcs,
                          KnownSrc, Depth + 1, Q, TLI);

      if (KnownSrc.isKnownNeverPosInfinity())
        Known.knownNot(fcPosInf);

      if (KnownSrc.isKnownNeverNaN() &&
          KnownSrc.cannotBeOrderedLessThanZero())
        Known.knownNot(fcNan);

      if (KnownSrc.isKnownNeverLogicalZero(*II->getFunction(), II->getType()))
        Known.knownNot(fcNegInf);

      break;
    }
    case Intrinsic::powi: {
      if ((InterestedClasses & fcNegative) == fcNone)
        break;

      const Value *Exp = II->getArgOperand(1);
      unsigned BitWidth =
          Exp->getType()->getScalarType()->getIntegerBitWidth();
      KnownBits ExponentKnownBits(BitWidth);
      computeKnownBits(Exp, DemandedElts, ExponentKnownBits, Depth + 1, Q);

      if (ExponentKnownBits.Zero[0]) { // Is even
        Known.knownNot(fcNegative);
        break;
      }

      // 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.
      KnownFPClass KnownSrc;
      computeKnownFPClass(II->getArgOperand(0), DemandedElts, fcNegative,
                          KnownSrc, Depth + 1, Q, TLI);
      if (KnownSrc.isKnownNever(fcNegative))
        Known.knownNot(fcNegative);
      break;
    }
    case Intrinsic::arithmetic_fence: {
      computeKnownFPClass(II->getArgOperand(0), DemandedElts,
                          InterestedClasses, Known, Depth + 1, Q, TLI);
      break;
    }
    case Intrinsic::experimental_constrained_sitofp:
    case Intrinsic::experimental_constrained_uitofp:
      // Cannot produce nan
      Known.knownNot(fcNan);

      // sitofp and uitofp turn into +0.0 for zero.
      Known.knownNot(fcNegZero);

      // Integers cannot be subnormal
      Known.knownNot(fcSubnormal);

      if (IID == Intrinsic::experimental_constrained_uitofp)
        Known.signBitMustBeZero();

      // TODO: Copy inf handling from instructions
      break;
    default:
      break;
    }
  }

  break;
}
case Instruction::FAdd:
case Instruction::FSub: {
  KnownFPClass KnownLHS, KnownRHS;
  computeKnownFPClass(Op->getOperand(1), DemandedElts, fcNan | fcInf,
                      KnownRHS, Depth + 1, Q, TLI);
  if (KnownRHS.isKnownNeverNaN()) {
    // RHS is canonically cheaper to compute. Skip inspecting the LHS if
    // there's no point.
    computeKnownFPClass(Op->getOperand(0), DemandedElts, fcNan | fcInf,
                        KnownLHS, Depth + 1, Q, TLI);
    // Adding positive and negative infinity produces NaN.
    // TODO: Check sign of infinities.
    if (KnownLHS.isKnownNeverNaN() &&
        (KnownLHS.isKnownNeverInfinity() || KnownRHS.isKnownNeverInfinity()))
      Known.knownNot(fcNan);
  }

  break;
}
case Instruction::FMul: {
  // X * X is always non-negative or a NaN.
  if (Op->getOperand(0) == Op->getOperand(1))
    Known.knownNot(fcNegative);

  if ((InterestedClasses & fcNan) != fcNan)
    break;

  KnownFPClass KnownLHS, KnownRHS;
  computeKnownFPClass(Op->getOperand(1), DemandedElts,
                      fcNan | fcInf | fcZero | fcSubnormal, KnownRHS,
                      Depth + 1, Q, TLI);
  if (KnownRHS.isKnownNeverNaN() &&
      (KnownRHS.isKnownNeverInfinity() || KnownRHS.isKnownNeverZero())) {
    computeKnownFPClass(Op->getOperand(0), DemandedElts,
                        fcNan | fcInf | fcZero, KnownLHS, Depth + 1, Q, TLI);
    if (!KnownLHS.isKnownNeverNaN())
      break;

    const Function *F = cast<Instruction>(Op)->getFunction();

    // If neither side can be zero (or nan) fmul never produces NaN.
    // TODO: Check operand combinations.
    // e.g. fmul nofpclass(inf nan zero), nofpclass(nan) -> nofpclass(nan)
    if ((KnownLHS.isKnownNeverInfinity() ||
         KnownLHS.isKnownNeverLogicalZero(*F, Op->getType())) &&
        (KnownRHS.isKnownNeverInfinity() ||
         KnownRHS.isKnownNeverLogicalZero(*F, Op->getType())))
      Known.knownNot(fcNan);
  }

  break;
}
case Instruction::FDiv:
case Instruction::FRem: {
  if (Op->getOperand(0) == Op->getOperand(1)) {
    // TODO: Could filter out snan if we inspect the operand
    if (Op->getOpcode() == Instruction::FDiv) {
      // X / X is always exactly 1.0 or a NaN.
      Known.KnownFPClasses = fcNan | fcPosNormal;
    } else {
      // X % X is always exactly [+-]0.0 or a NaN.
      Known.KnownFPClasses = fcNan | fcZero;
    }

    break;
  }

  const bool WantNan = (InterestedClasses & fcNan) != fcNone;
  const bool WantNegative = (InterestedClasses & fcNegative) != fcNone;
  const bool WantPositive =
      Opc == Instruction::FRem && (InterestedClasses & fcPositive) != fcNone;
  if (!WantNan && !WantNegative && !WantPositive)
    break;

  KnownFPClass KnownLHS, KnownRHS;

  computeKnownFPClass(Op->getOperand(1), DemandedElts,
                      fcNan | fcInf | fcZero | fcNegative, KnownRHS,
                      Depth + 1, Q, TLI);

  bool KnowSomethingUseful =
      KnownRHS.isKnownNeverNaN() || KnownRHS.isKnownNever(fcNegative);

  if (KnowSomethingUseful || WantPositive) {
    const FPClassTest InterestedLHS =
        WantPositive ? fcAllFlags
                     : fcNan | fcInf | fcZero | fcSubnormal | fcNegative;

    computeKnownFPClass(Op->getOperand(0), DemandedElts,
                        InterestedClasses & InterestedLHS, KnownLHS,
                        Depth + 1, Q, TLI);
  }

  const Function *F = cast<Instruction>(Op)->getFunction();

  if (Op->getOpcode() == Instruction::FDiv) {
    // Only 0/0, Inf/Inf produce NaN.
    if (KnownLHS.isKnownNeverNaN() && KnownRHS.isKnownNeverNaN() &&
        (KnownLHS.isKnownNeverInfinity() ||
         KnownRHS.isKnownNeverInfinity()) &&
        (KnownLHS.isKnownNeverLogicalZero(*F, Op->getType()) ||
         KnownRHS.isKnownNeverLogicalZero(*F, Op->getType()))) {
      Known.knownNot(fcNan);
    }

    // X / -0.0 is -Inf (or NaN).
    // +X / +X is +X
    if (KnownLHS.isKnownNever(fcNegative) && KnownRHS.isKnownNever(fcNegative))
      Known.knownNot(fcNegative);
  } else {
    // Inf REM x and x REM 0 produce NaN.
    if (KnownLHS.isKnownNeverNaN() && KnownRHS.isKnownNeverNaN() &&
        KnownLHS.isKnownNeverInfinity() &&
        KnownRHS.isKnownNeverLogicalZero(*F, Op->getType())) {
      Known.knownNot(fcNan);
    }

    // The sign for frem is the same as the first operand.
    if (KnownLHS.isKnownNever(fcNegative))
      Known.knownNot(fcNegative);
    if (KnownLHS.isKnownNever(fcPositive))
      Known.knownNot(fcPositive);
  }

  break;
}
case Instruction::FPExt: {
  // Infinity, nan and zero propagate from source.
  computeKnownFPClass(Op->getOperand(0), DemandedElts, InterestedClasses,
                      Known, Depth + 1, Q, TLI);

  const fltSemantics &DstTy =
      Op->getType()->getScalarType()->getFltSemantics();
  const fltSemantics &SrcTy =
      Op->getOperand(0)->getType()->getScalarType()->getFltSemantics();

  // All subnormal inputs should be in the normal range in the result type.
  if (APFloat::isRepresentableAsNormalIn(SrcTy, DstTy))
    Known.knownNot(fcSubnormal);

  // Sign bit of a nan isn't guaranteed.
  if (!Known.isKnownNeverNaN())
    Known.SignBit = std::nullopt;
  break;
}
case Instruction::FPTrunc: {
  computeKnownFPClassForFPTrunc(Op, DemandedElts, InterestedClasses, Known,
                                Depth, Q, TLI);
  break;
}
case Instruction::SIToFP:
case Instruction::UIToFP: {
  // Cannot produce nan
  Known.knownNot(fcNan);

  // Integers cannot be subnormal
  Known.knownNot(fcSubnormal);

  // sitofp and uitofp turn into +0.0 for zero.
  Known.knownNot(fcNegZero);
  if (Op->getOpcode() == Instruction::UIToFP)
    Known.signBitMustBeZero();

  if (InterestedClasses & fcInf) {
    // 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 = Op->getOperand(0)->getType()->getScalarSizeInBits();
    if (Op->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 = Op->getType()->getScalarType();
    if (ilogb(APFloat::getLargest(FPTy->getFltSemantics())) >= IntSize)
      Known.knownNot(fcInf);
  }

  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 = Op->getOperand(0);
  const Value *Idx = Op->getOperand(1);
  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 computeKnownFPClass(Vec, DemandedVecElts, InterestedClasses, Known,
                               Depth + 1, Q, TLI);
  }

  break;
}
case Instruction::InsertElement: {
  if (isa<ScalableVectorType>(Op->getType()))
    return;

  const Value *Vec = Op->getOperand(0);
  const Value *Elt = Op->getOperand(1);
  auto *CIdx = dyn_cast<ConstantInt>(Op->getOperand(2));
  // Early out if the index is non-constant or out-of-range.
  unsigned NumElts = DemandedElts.getBitWidth();
  if (!CIdx || CIdx->getValue().uge(NumElts))
    return;

  unsigned EltIdx = CIdx->getZExtValue();
  // Do we demand the inserted element?
  if (DemandedElts[EltIdx]) {
    computeKnownFPClass(Elt, Known, InterestedClasses, Depth + 1, Q, TLI);
    // If we don't know any bits, early out.
    if (Known.isUnknown())
      break;
  } else {
    Known.KnownFPClasses = fcNone;
  }

  // We don't need the base vector element that has been inserted.
  APInt DemandedVecElts = DemandedElts;
  DemandedVecElts.clearBit(EltIdx);
  if (!!DemandedVecElts) {
    KnownFPClass Known2;
    computeKnownFPClass(Vec, DemandedVecElts, InterestedClasses, Known2,
                        Depth + 1, Q, TLI);
    Known |= Known2;
  }

  break;
}
case Instruction::ShuffleVector: {
  // For undef elements, we don't know anything about the common state of
  // the shuffle result.
  APInt DemandedLHS, DemandedRHS;
  auto *Shuf = dyn_cast<ShuffleVectorInst>(Op);
  if (!Shuf || !getShuffleDemandedElts(Shuf, DemandedElts, DemandedLHS, DemandedRHS))
    return;

  if (!!DemandedLHS) {
    const Value *LHS = Shuf->getOperand(0);
    computeKnownFPClass(LHS, DemandedLHS, InterestedClasses, Known,
                        Depth + 1, Q, TLI);

    // If we don't know any bits, early out.
    if (Known.isUnknown())
      break;
  } else {
    Known.KnownFPClasses = fcNone;
  }

  if (!!DemandedRHS) {
    KnownFPClass Known2;
    const Value *RHS = Shuf->getOperand(1);
    computeKnownFPClass(RHS, DemandedRHS, InterestedClasses, Known2,
                        Depth + 1, Q, TLI);
    Known |= Known2;
  }

  break;
}
case Instruction::ExtractValue: {
  computeKnownFPClass(Op->getOperand(0), DemandedElts, InterestedClasses,
                      Known, Depth + 1, Q, TLI);
  break;
}
default:
  break;
}
5240}

5242KnownFPClass llvm::computeKnownFPClass(
  const Value *V, const APInt &DemandedElts, const DataLayout &DL,
  FPClassTest InterestedClasses, unsigned Depth, const TargetLibraryInfo *TLI,
  AssumptionCache *AC, const Instruction *CxtI, const DominatorTree *DT,
  OptimizationRemarkEmitter *ORE, bool UseInstrInfo) {
KnownFPClass KnownClasses;
::computeKnownFPClass(V, DemandedElts, InterestedClasses, KnownClasses, Depth,
                      Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo, ORE),
                      TLI);
return KnownClasses;
5252}

5254KnownFPClass
5255llvm::computeKnownFPClass(const Value *V, const DataLayout &DL,
                        FPClassTest InterestedClasses, unsigned Depth,
                        const TargetLibraryInfo *TLI, AssumptionCache *AC,
                        const Instruction *CxtI, const DominatorTree *DT,
                        OptimizationRemarkEmitter *ORE, bool UseInstrInfo) {
KnownFPClass Known;
::computeKnownFPClass(V, Known, InterestedClasses, Depth,
                      Query(DL, AC, safeCxtI(V, CxtI), DT, UseInstrInfo, ORE),
                      TLI);
return Known;
5265}

5267Value *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!")(static_cast <bool> (CI->getBitWidth() > 8 &&
 "8 bits should be handled above!") ? void (0) : __assert_fail
 ("CI->getBitWidth() > 8 && \"8 bits should be handled above!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5317, __extension__ __PRETTY_FUNCTION__
));
    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;
5366}

5368// This is the recursive version of BuildSubAggregate. It takes a few different
5369// arguments. Idxs is the index within the nested struct From that we are
5370// looking at now (which is of type IndexedType). IdxSkip is the number of
5371// indices from Idxs that should be left out when inserting into the resulting
5372// struct. To is the result struct built so far, new insertvalue instructions
5373// build on that.
5374static 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);
5419}

5421// This helper takes a nested struct and extracts a part of it (which is again a
5422// struct) into a new value. For example, given the struct:
5423// { a, { b, { c, d }, e } }
5424// and the indices "1, 1" this returns
5425// { c, d }.
5426//
5427// It does this by inserting an insertvalue for each element in the resulting
5428// struct, as opposed to just inserting a single struct. This will only work if
5429// each of the elements of the substruct are known (ie, inserted into From by an
5430// insertvalue instruction somewhere).
5431//
5432// All inserted insertvalue instructions are inserted before InsertBefore
5433static Value *BuildSubAggregate(Value *From, ArrayRef<unsigned> idx_range,
                              Instruction *InsertBefore) {
assert(InsertBefore && "Must have someplace to insert!")(static_cast <bool> (InsertBefore && "Must have someplace to insert!"
) ? void (0) : __assert_fail ("InsertBefore && \"Must have someplace to insert!\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5435, __extension__ __PRETTY_FUNCTION__
));
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);
5443}

5445/// Given an aggregate and a sequence of indices, see if the scalar value
5446/// indexed is already around as a register, for example if it was inserted
5447/// directly into the aggregate.
5448///
5449/// If InsertBefore is not null, this function will duplicate (modified)
5450/// insertvalues when a part of a nested struct is extracted.
5451Value *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()) &&(static_cast <bool> ((V->getType()->isStructTy() ||
 V->getType()->isArrayTy()) && "Not looking at a struct or array?"
) ? void (0) : __assert_fail ("(V->getType()->isStructTy() || V->getType()->isArrayTy()) && \"Not looking at a struct or array?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5459, __extension__ __PRETTY_FUNCTION__
))
       "Not looking at a struct or array?")(static_cast <bool> ((V->getType()->isStructTy() ||
 V->getType()->isArrayTy()) && "Not looking at a struct or array?"
) ? void (0) : __assert_fail ("(V->getType()->isStructTy() || V->getType()->isArrayTy()) && \"Not looking at a struct or array?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5459, __extension__ __PRETTY_FUNCTION__
));
assert(ExtractValueInst::getIndexedType(V->getType(), idx_range) &&(static_cast <bool> (ExtractValueInst::getIndexedType(V
->getType(), idx_range) && "Invalid indices for type?"
) ? void (0) : __assert_fail ("ExtractValueInst::getIndexedType(V->getType(), idx_range) && \"Invalid indices for type?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5461, __extension__ __PRETTY_FUNCTION__
))
       "Invalid indices for type?")(static_cast <bool> (ExtractValueInst::getIndexedType(V
->getType(), idx_range) && "Invalid indices for type?"
) ? void (0) : __assert_fail ("ExtractValueInst::getIndexedType(V->getType(), idx_range) && \"Invalid indices for type?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5461, __extension__ __PRETTY_FUNCTION__
));

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(static_cast <bool> (Idxs.size() == size && "Number of indices added not correct?"
) ? void (0) : __assert_fail ("Idxs.size() == size && \"Number of indices added not correct?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5525, __extension__ __PRETTY_FUNCTION__
))
         && "Number of indices added not correct?")(static_cast <bool> (Idxs.size() == size && "Number of indices added not correct?"
) ? void (0) : __assert_fail ("Idxs.size() == size && \"Number of indices added not correct?\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5525, __extension__ __PRETTY_FUNCTION__
));

  return FindInsertedValue(I->getAggregateOperand(), Idxs, InsertBefore);
}
// Otherwise, we don't know (such as, extracting from a function return value
// or load instruction)
return nullptr;
5532}

5534bool 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;
5553}

5555// If V refers to an initialized global constant, set Slice either to
5556// its initializer if the size of its elements equals ElementSize, or,
5557// for ElementSize == 8, to its representation as an array of unsiged
5558// char. Return true on success.
5559// Offset is in the unit "nr of ElementSize sized elements".
5560bool llvm::getConstantDataArrayInfo(const Value *V,
                                  ConstantDataArraySlice &Slice,
                                  unsigned ElementSize, uint64_t Offset) {
assert(V && "V should not be null.")(static_cast <bool> (V && "V should not be null."
) ? void (0) : __assert_fail ("V && \"V should not be null.\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5563, __extension__ __PRETTY_FUNCTION__
));
2
←
Assuming 'V' is non-null→
3
←
'?' condition is true→
assert((ElementSize % 8) == 0 &&(static_cast <bool> ((ElementSize % 8) == 0 && "ElementSize expected to be a multiple of the size of a byte."
) ? void (0) : __assert_fail ("(ElementSize % 8) == 0 && \"ElementSize expected to be a multiple of the size of a byte.\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5565, __extension__ __PRETTY_FUNCTION__
))
4
←
'?' condition is true→
       "ElementSize expected to be a multiple of the size of a byte.")(static_cast <bool> ((ElementSize % 8) == 0 && "ElementSize expected to be a multiple of the size of a byte."
) ? void (0) : __assert_fail ("(ElementSize % 8) == 0 && \"ElementSize expected to be a multiple of the size of a byte.\""
, "llvm/lib/Analysis/ValueTracking.cpp", 5565, __extension__ __PRETTY_FUNCTION__
));
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));
5
←
Assuming the object is a 'CastReturnType'→
if (!GV5.1
'GV' is non-null
 || !GV->isConstant() || !GV->hasDefinitiveInitializer())
6
←
Assuming the condition is false→
7
←
Taking false branch→
  // 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,
8
←
Assuming the condition is false→
9
←
Taking false branch→
                                               /*AllowNonInbounds*/ true))
  // Fail if a constant offset could not be determined.
  return false;

uint64_t StartIdx = Off.getLimitedValue();
if (StartIdx == UINT64_MAX(18446744073709551615UL))
10
←
Assuming 'StartIdx' is not equal to UINT64_MAX→
11
←
Taking false branch→
  // 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)
12
←
Taking false branch→
  return false;

Offset += StartIdx / ElementSizeInBytes;
ConstantDataArray *Array = nullptr;
ArrayType *ArrayTy = nullptr;

if (GV->getInitializer()->isNullValue()) {
13
←
Assuming the condition is false→
14
←
Taking false branch→
  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 *ArrayInit15.1
'ArrayInit' is null
 = dyn_cast<ConstantDataArray>(Init)) {
15
←
Assuming 'Init' is not a 'CastReturnType'→
16
←
Taking false branch→
  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 (!Array16.1
'Array' is null
) {
17
←
Taking true branch→
  if (ElementSize17.1
'ElementSize' is equal to 8
 != 8)
18
←
Taking false branch→
    // 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)
19
←
Assuming 'Init' is non-null→
20
←
Taking false branch→
    return false;

  Offset = 0;
  Array = dyn_cast<ConstantDataArray>(Init);
21
←
Assuming 'Init' is a 'CastReturnType'→
  ArrayTy = dyn_cast<ArrayType>(Init->getType());
22
←
Assuming the object is not a 'CastReturnType'→
23
←
Null pointer value stored to 'ArrayTy'→
}

uint64_t NumElts = ArrayTy->getArrayNumElements();
24
←
Called C++ object pointer is null
if (Offset > NumElts)
  return false;

Slice.Array = Array;
Slice.Offset = Offset;
Slice.Length = NumElts - Offset;
return true;
5649}

5651/// Extract bytes from the initializer of the constant array V, which need
5652/// not be a nul-terminated string.  On success, store the bytes in Str and
5653/// return true.  When TrimAtNul is set, Str will contain only the bytes up
5654/// to but not including the first nul.  Return false on failure.
5655bool llvm::getConstantStringInfo(const Value *V, StringRef &Str,
                               bool TrimAtNul) {
ConstantDataArraySlice Slice;
if (!getConstantDataArrayInfo(V, Slice, 8))
1
Calling 'getConstantDataArrayInfo'→
  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;
5693}

5695// These next two are very similar to the above, but also look through PHI
5696// nodes.
5697// TODO: See if we can integrate these two together.

5699/// If we can compute the length of the string pointed to by
5700/// the specified pointer, return 'len+1'.  If we can't, return 0.
5701static 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;
5762}

5764/// If we can compute the length of the string pointed to by
5765/// the specified pointer, return 'len+1'.  If we can't, return 0.
5766uint64_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;
5775}

5777const Value *
5778llvm::getArgumentAliasingToReturnedPointer(const CallBase *Call,
                                         bool MustPreserveNullness) {
assert(Call &&(static_cast <bool> (Call && "getArgume