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

Bug Summary

File:	build/source/llvm/lib/Analysis/MemorySSA.cpp
Warning:	line 2024, column 5 Called C++ object pointer is null

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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 MemorySSA.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/tools/clang/stage2-bins -resource-dir /usr/lib/llvm-17/lib/clang/17 -D _DEBUG -D _GLIBCXX_ASSERTIONS -D _GNU_SOURCE -D _LIBCPP_ENABLE_ASSERTIONS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I lib/Analysis -I /build/source/llvm/lib/Analysis -I include -I /build/source/llvm/include -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/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fmacro-prefix-map=/build/source/= -fcoverage-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fcoverage-prefix-map=/build/source/= -source-date-epoch 1683717183 -O2 -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/tools/clang/stage2-bins -fdebug-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -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/MemorySSA.cpp

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

→

1//===- MemorySSA.cpp - Memory SSA Builder ---------------------------------===//
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 implements the MemorySSA class.
10//
11//===----------------------------------------------------------------------===//

13#include "llvm/Analysis/MemorySSA.h"
14#include "llvm/ADT/DenseMap.h"
15#include "llvm/ADT/DenseMapInfo.h"
16#include "llvm/ADT/DenseSet.h"
17#include "llvm/ADT/DepthFirstIterator.h"
18#include "llvm/ADT/Hashing.h"
19#include "llvm/ADT/STLExtras.h"
20#include "llvm/ADT/SmallPtrSet.h"
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/ADT/StringExtras.h"
23#include "llvm/ADT/iterator.h"
24#include "llvm/ADT/iterator_range.h"
25#include "llvm/Analysis/AliasAnalysis.h"
26#include "llvm/Analysis/CFGPrinter.h"
27#include "llvm/Analysis/IteratedDominanceFrontier.h"
28#include "llvm/Analysis/MemoryLocation.h"
29#include "llvm/Config/llvm-config.h"
30#include "llvm/IR/AssemblyAnnotationWriter.h"
31#include "llvm/IR/BasicBlock.h"
32#include "llvm/IR/Dominators.h"
33#include "llvm/IR/Function.h"
34#include "llvm/IR/Instruction.h"
35#include "llvm/IR/Instructions.h"
36#include "llvm/IR/IntrinsicInst.h"
37#include "llvm/IR/LLVMContext.h"
38#include "llvm/IR/Operator.h"
39#include "llvm/IR/PassManager.h"
40#include "llvm/IR/Use.h"
41#include "llvm/InitializePasses.h"
42#include "llvm/Pass.h"
43#include "llvm/Support/AtomicOrdering.h"
44#include "llvm/Support/Casting.h"
45#include "llvm/Support/CommandLine.h"
46#include "llvm/Support/Compiler.h"
47#include "llvm/Support/Debug.h"
48#include "llvm/Support/ErrorHandling.h"
49#include "llvm/Support/FormattedStream.h"
50#include "llvm/Support/GraphWriter.h"
51#include "llvm/Support/raw_ostream.h"
52#include <algorithm>
53#include <cassert>
54#include <iterator>
55#include <memory>
56#include <utility>

58using namespace llvm;

60#define DEBUG_TYPE"memoryssa" "memoryssa"

62static cl::opt<std::string>
  DotCFGMSSA("dot-cfg-mssa",
             cl::value_desc("file name for generated dot file"),
             cl::desc("file name for generated dot file"), cl::init(""));

67INITIALIZE_PASS_BEGIN(MemorySSAWrapperPass, "memoryssa", "Memory SSA", false,static void *initializeMemorySSAWrapperPassPassOnce(PassRegistry
 &Registry) {
                    true)static void *initializeMemorySSAWrapperPassPassOnce(PassRegistry
 &Registry) {
69INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
70INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry);
71INITIALIZE_PASS_END(MemorySSAWrapperPass, "memoryssa", "Memory SSA", false,PassInfo *PI = new PassInfo( "Memory SSA", "memoryssa", &
MemorySSAWrapperPass::ID, PassInfo::NormalCtor_t(callDefaultCtor
<MemorySSAWrapperPass>), false, true); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeMemorySSAWrapperPassPassFlag
; void llvm::initializeMemorySSAWrapperPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySSAWrapperPassPassFlag
, initializeMemorySSAWrapperPassPassOnce, std::ref(Registry))
; }
                  true)PassInfo *PI = new PassInfo( "Memory SSA", "memoryssa", &
MemorySSAWrapperPass::ID, PassInfo::NormalCtor_t(callDefaultCtor
<MemorySSAWrapperPass>), false, true); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeMemorySSAWrapperPassPassFlag
; void llvm::initializeMemorySSAWrapperPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySSAWrapperPassPassFlag
, initializeMemorySSAWrapperPassPassOnce, std::ref(Registry))
; }

74INITIALIZE_PASS_BEGIN(MemorySSAPrinterLegacyPass, "print-memoryssa",static void *initializeMemorySSAPrinterLegacyPassPassOnce(PassRegistry
 &Registry) {
                    "Memory SSA Printer", false, false)static void *initializeMemorySSAPrinterLegacyPassPassOnce(PassRegistry
 &Registry) {
76INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)initializeMemorySSAWrapperPassPass(Registry);
77INITIALIZE_PASS_END(MemorySSAPrinterLegacyPass, "print-memoryssa",PassInfo *PI = new PassInfo( "Memory SSA Printer", "print-memoryssa"
, &MemorySSAPrinterLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<MemorySSAPrinterLegacyPass>), false, false
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeMemorySSAPrinterLegacyPassPassFlag; void
 llvm::initializeMemorySSAPrinterLegacyPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySSAPrinterLegacyPassPassFlag
, initializeMemorySSAPrinterLegacyPassPassOnce, std::ref(Registry
)); }
                  "Memory SSA Printer", false, false)PassInfo *PI = new PassInfo( "Memory SSA Printer", "print-memoryssa"
, &MemorySSAPrinterLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<MemorySSAPrinterLegacyPass>), false, false
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeMemorySSAPrinterLegacyPassPassFlag; void
 llvm::initializeMemorySSAPrinterLegacyPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySSAPrinterLegacyPassPassFlag
, initializeMemorySSAPrinterLegacyPassPassOnce, std::ref(Registry
)); }

80static cl::opt<unsigned> MaxCheckLimit(
  "memssa-check-limit", cl::Hidden, cl::init(100),
  cl::desc("The maximum number of stores/phis MemorySSA"
           "will consider trying to walk past (default = 100)"));

85// Always verify MemorySSA if expensive checking is enabled.
86#ifdef EXPENSIVE_CHECKS
87bool llvm::VerifyMemorySSA = true;
88#else
89bool llvm::VerifyMemorySSA = false;
90#endif

92static cl::opt<bool, true>
  VerifyMemorySSAX("verify-memoryssa", cl::location(VerifyMemorySSA),
                   cl::Hidden, cl::desc("Enable verification of MemorySSA."));

96const static char LiveOnEntryStr[] = "liveOnEntry";

98namespace {

100/// An assembly annotator class to print Memory SSA information in
101/// comments.
102class MemorySSAAnnotatedWriter : public AssemblyAnnotationWriter {
const MemorySSA *MSSA;

105public:
MemorySSAAnnotatedWriter(const MemorySSA *M) : MSSA(M) {}

void emitBasicBlockStartAnnot(const BasicBlock *BB,
                              formatted_raw_ostream &OS) override {
  if (MemoryAccess *MA = MSSA->getMemoryAccess(BB))
    OS << "; " << *MA << "\n";
}

void emitInstructionAnnot(const Instruction *I,
                          formatted_raw_ostream &OS) override {
  if (MemoryAccess *MA = MSSA->getMemoryAccess(I))
    OS << "; " << *MA << "\n";
}
119};

121/// An assembly annotator class to print Memory SSA information in
122/// comments.
123class MemorySSAWalkerAnnotatedWriter : public AssemblyAnnotationWriter {
MemorySSA *MSSA;
MemorySSAWalker *Walker;
BatchAAResults BAA;

128public:
MemorySSAWalkerAnnotatedWriter(MemorySSA *M)
    : MSSA(M), Walker(M->getWalker()), BAA(M->getAA()) {}

void emitBasicBlockStartAnnot(const BasicBlock *BB,
                              formatted_raw_ostream &OS) override {
  if (MemoryAccess *MA = MSSA->getMemoryAccess(BB))
    OS << "; " << *MA << "\n";
}

void emitInstructionAnnot(const Instruction *I,
                          formatted_raw_ostream &OS) override {
  if (MemoryAccess *MA = MSSA->getMemoryAccess(I)) {
    MemoryAccess *Clobber = Walker->getClobberingMemoryAccess(MA, BAA);
    OS << "; " << *MA;
    if (Clobber) {
      OS << " - clobbered by ";
      if (MSSA->isLiveOnEntryDef(Clobber))
        OS << LiveOnEntryStr;
      else
        OS << *Clobber;
    }
    OS << "\n";
  }
}
153};

155} // namespace

157namespace {

159/// Our current alias analysis API differentiates heavily between calls and
160/// non-calls, and functions called on one usually assert on the other.
161/// This class encapsulates the distinction to simplify other code that wants
162/// "Memory affecting instructions and related data" to use as a key.
163/// For example, this class is used as a densemap key in the use optimizer.
164class MemoryLocOrCall {
165public:
bool IsCall = false;

MemoryLocOrCall(MemoryUseOrDef *MUD)
    : MemoryLocOrCall(MUD->getMemoryInst()) {}
MemoryLocOrCall(const MemoryUseOrDef *MUD)
    : MemoryLocOrCall(MUD->getMemoryInst()) {}

MemoryLocOrCall(Instruction *Inst) {
  if (auto *C = dyn_cast<CallBase>(Inst)) {
    IsCall = true;
    Call = C;
  } else {
    IsCall = false;
    // There is no such thing as a memorylocation for a fence inst, and it is
    // unique in that regard.
    if (!isa<FenceInst>(Inst))
      Loc = MemoryLocation::get(Inst);
  }
}

explicit MemoryLocOrCall(const MemoryLocation &Loc) : Loc(Loc) {}

const CallBase *getCall() const {
  assert(IsCall)(static_cast <bool> (IsCall) ? void (0) : __assert_fail
 ("IsCall", "llvm/lib/Analysis/MemorySSA.cpp", 189, __extension__
 __PRETTY_FUNCTION__));
  return Call;
}

MemoryLocation getLoc() const {
  assert(!IsCall)(static_cast <bool> (!IsCall) ? void (0) : __assert_fail
 ("!IsCall", "llvm/lib/Analysis/MemorySSA.cpp", 194, __extension__
 __PRETTY_FUNCTION__));
  return Loc;
}

bool operator==(const MemoryLocOrCall &Other) const {
  if (IsCall != Other.IsCall)
    return false;

  if (!IsCall)
    return Loc == Other.Loc;

  if (Call->getCalledOperand() != Other.Call->getCalledOperand())
    return false;

  return Call->arg_size() == Other.Call->arg_size() &&
         std::equal(Call->arg_begin(), Call->arg_end(),
                    Other.Call->arg_begin());
}

213private:
union {
  const CallBase *Call;
  MemoryLocation Loc;
};
218};

220} // end anonymous namespace

222namespace llvm {

224template <> struct DenseMapInfo<MemoryLocOrCall> {
static inline MemoryLocOrCall getEmptyKey() {
  return MemoryLocOrCall(DenseMapInfo<MemoryLocation>::getEmptyKey());
}

static inline MemoryLocOrCall getTombstoneKey() {
  return MemoryLocOrCall(DenseMapInfo<MemoryLocation>::getTombstoneKey());
}

static unsigned getHashValue(const MemoryLocOrCall &MLOC) {
  if (!MLOC.IsCall)
    return hash_combine(
        MLOC.IsCall,
        DenseMapInfo<MemoryLocation>::getHashValue(MLOC.getLoc()));

  hash_code hash =
      hash_combine(MLOC.IsCall, DenseMapInfo<const Value *>::getHashValue(
                                    MLOC.getCall()->getCalledOperand()));

  for (const Value *Arg : MLOC.getCall()->args())
    hash = hash_combine(hash, DenseMapInfo<const Value *>::getHashValue(Arg));
  return hash;
}

static bool isEqual(const MemoryLocOrCall &LHS, const MemoryLocOrCall &RHS) {
  return LHS == RHS;
}
251};

253} // end namespace llvm

255/// This does one-way checks to see if Use could theoretically be hoisted above
256/// MayClobber. This will not check the other way around.
257///
258/// This assumes that, for the purposes of MemorySSA, Use comes directly after
259/// MayClobber, with no potentially clobbering operations in between them.
260/// (Where potentially clobbering ops are memory barriers, aliased stores, etc.)
261static bool areLoadsReorderable(const LoadInst *Use,
                              const LoadInst *MayClobber) {
bool VolatileUse = Use->isVolatile();
bool VolatileClobber = MayClobber->isVolatile();
// Volatile operations may never be reordered with other volatile operations.
if (VolatileUse && VolatileClobber)
  return false;
// Otherwise, volatile doesn't matter here. From the language reference:
// 'optimizers may change the order of volatile operations relative to
// non-volatile operations.'"

// If a load is seq_cst, it cannot be moved above other loads. If its ordering
// is weaker, it can be moved above other loads. We just need to be sure that
// MayClobber isn't an acquire load, because loads can't be moved above
// acquire loads.
//
// Note that this explicitly *does* allow the free reordering of monotonic (or
// weaker) loads of the same address.
bool SeqCstUse = Use->getOrdering() == AtomicOrdering::SequentiallyConsistent;
bool MayClobberIsAcquire = isAtLeastOrStrongerThan(MayClobber->getOrdering(),
                                                   AtomicOrdering::Acquire);
return !(SeqCstUse || MayClobberIsAcquire);
283}

285template <typename AliasAnalysisType>
286static bool
287instructionClobbersQuery(const MemoryDef *MD, const MemoryLocation &UseLoc,
                       const Instruction *UseInst, AliasAnalysisType &AA) {
Instruction *DefInst = MD->getMemoryInst();
assert(DefInst && "Defining instruction not actually an instruction")(static_cast <bool> (DefInst && "Defining instruction not actually an instruction"
) ? void (0) : __assert_fail ("DefInst && \"Defining instruction not actually an instruction\""
, "llvm/lib/Analysis/MemorySSA.cpp", 290, __extension__ __PRETTY_FUNCTION__
));

if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(DefInst)) {
  // These intrinsics will show up as affecting memory, but they are just
  // markers, mostly.
  //
  // FIXME: We probably don't actually want MemorySSA to model these at all
  // (including creating MemoryAccesses for them): we just end up inventing
  // clobbers where they don't really exist at all. Please see D43269 for
  // context.
  switch (II->getIntrinsicID()) {
  case Intrinsic::invariant_start:
  case Intrinsic::invariant_end:
  case Intrinsic::assume:
  case Intrinsic::experimental_noalias_scope_decl:
  case Intrinsic::pseudoprobe:
    return false;
  case Intrinsic::dbg_declare:
  case Intrinsic::dbg_label:
  case Intrinsic::dbg_value:
    llvm_unreachable("debuginfo shouldn't have associated defs!")::llvm::llvm_unreachable_internal("debuginfo shouldn't have associated defs!"
, "llvm/lib/Analysis/MemorySSA.cpp", 310);
  default:
    break;
  }
}

if (auto *CB = dyn_cast_or_null<CallBase>(UseInst)) {
  ModRefInfo I = AA.getModRefInfo(DefInst, CB);
  return isModOrRefSet(I);
}

if (auto *DefLoad = dyn_cast<LoadInst>(DefInst))
  if (auto *UseLoad = dyn_cast_or_null<LoadInst>(UseInst))
    return !areLoadsReorderable(UseLoad, DefLoad);

ModRefInfo I = AA.getModRefInfo(DefInst, UseLoc);
return isModSet(I);
327}

329template <typename AliasAnalysisType>
330static bool instructionClobbersQuery(MemoryDef *MD, const MemoryUseOrDef *MU,
                                   const MemoryLocOrCall &UseMLOC,
                                   AliasAnalysisType &AA) {
// FIXME: This is a temporary hack to allow a single instructionClobbersQuery
// to exist while MemoryLocOrCall is pushed through places.
if (UseMLOC.IsCall)
  return instructionClobbersQuery(MD, MemoryLocation(), MU->getMemoryInst(),
                                  AA);
return instructionClobbersQuery(MD, UseMLOC.getLoc(), MU->getMemoryInst(),
                                AA);
340}

342// Return true when MD may alias MU, return false otherwise.
343bool MemorySSAUtil::defClobbersUseOrDef(MemoryDef *MD, const MemoryUseOrDef *MU,
                                      AliasAnalysis &AA) {
return instructionClobbersQuery(MD, MU, MemoryLocOrCall(MU), AA);
346}

348namespace {

350struct UpwardsMemoryQuery {
// True if our original query started off as a call
bool IsCall = false;
// The pointer location we started the query with. This will be empty if
// IsCall is true.
MemoryLocation StartingLoc;
// This is the instruction we were querying about.
const Instruction *Inst = nullptr;
// The MemoryAccess we actually got called with, used to test local domination
const MemoryAccess *OriginalAccess = nullptr;
bool SkipSelfAccess = false;

UpwardsMemoryQuery() = default;

UpwardsMemoryQuery(const Instruction *Inst, const MemoryAccess *Access)
    : IsCall(isa<CallBase>(Inst)), Inst(Inst), OriginalAccess(Access) {
  if (!IsCall)
    StartingLoc = MemoryLocation::get(Inst);
}
369};

371} // end anonymous namespace

373static bool isUseTriviallyOptimizableToLiveOnEntry(BatchAAResults &AA,
                                                 const Instruction *I) {
// If the memory can't be changed, then loads of the memory can't be
// clobbered.
if (auto *LI = dyn_cast<LoadInst>(I)) {
  return I->hasMetadata(LLVMContext::MD_invariant_load) ||
         !isModSet(AA.getModRefInfoMask(MemoryLocation::get(LI)));
}
return false;
382}

384/// Verifies that `Start` is clobbered by `ClobberAt`, and that nothing
385/// inbetween `Start` and `ClobberAt` can clobbers `Start`.
386///
387/// This is meant to be as simple and self-contained as possible. Because it
388/// uses no cache, etc., it can be relatively expensive.
389///
390/// \param Start     The MemoryAccess that we want to walk from.
391/// \param ClobberAt A clobber for Start.
392/// \param StartLoc  The MemoryLocation for Start.
393/// \param MSSA      The MemorySSA instance that Start and ClobberAt belong to.
394/// \param Query     The UpwardsMemoryQuery we used for our search.
395/// \param AA        The AliasAnalysis we used for our search.
396/// \param AllowImpreciseClobber Always false, unless we do relaxed verify.

398LLVM_ATTRIBUTE_UNUSED__attribute__((__unused__)) static void
399checkClobberSanity(const MemoryAccess *Start, MemoryAccess *ClobberAt,
                 const MemoryLocation &StartLoc, const MemorySSA &MSSA,
                 const UpwardsMemoryQuery &Query, BatchAAResults &AA,
                 bool AllowImpreciseClobber = false) {
assert(MSSA.dominates(ClobberAt, Start) && "Clobber doesn't dominate start?")(static_cast <bool> (MSSA.dominates(ClobberAt, Start) &&
 "Clobber doesn't dominate start?") ? void (0) : __assert_fail
 ("MSSA.dominates(ClobberAt, Start) && \"Clobber doesn't dominate start?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 403, __extension__ __PRETTY_FUNCTION__
));

if (MSSA.isLiveOnEntryDef(Start)) {
  assert(MSSA.isLiveOnEntryDef(ClobberAt) &&(static_cast <bool> (MSSA.isLiveOnEntryDef(ClobberAt) &&
 "liveOnEntry must clobber itself") ? void (0) : __assert_fail
 ("MSSA.isLiveOnEntryDef(ClobberAt) && \"liveOnEntry must clobber itself\""
, "llvm/lib/Analysis/MemorySSA.cpp", 407, __extension__ __PRETTY_FUNCTION__
))
         "liveOnEntry must clobber itself")(static_cast <bool> (MSSA.isLiveOnEntryDef(ClobberAt) &&
 "liveOnEntry must clobber itself") ? void (0) : __assert_fail
 ("MSSA.isLiveOnEntryDef(ClobberAt) && \"liveOnEntry must clobber itself\""
, "llvm/lib/Analysis/MemorySSA.cpp", 407, __extension__ __PRETTY_FUNCTION__
));
  return;
}

bool FoundClobber = false;
DenseSet<ConstMemoryAccessPair> VisitedPhis;
SmallVector<ConstMemoryAccessPair, 8> Worklist;
Worklist.emplace_back(Start, StartLoc);
// Walk all paths from Start to ClobberAt, while looking for clobbers. If one
// is found, complain.
while (!Worklist.empty()) {
  auto MAP = Worklist.pop_back_val();
  // All we care about is that nothing from Start to ClobberAt clobbers Start.
  // We learn nothing from revisiting nodes.
  if (!VisitedPhis.insert(MAP).second)
    continue;

  for (const auto *MA : def_chain(MAP.first)) {
    if (MA == ClobberAt) {
      if (const auto *MD = dyn_cast<MemoryDef>(MA)) {
        // instructionClobbersQuery isn't essentially free, so don't use `|=`,
        // since it won't let us short-circuit.
        //
        // Also, note that this can't be hoisted out of the `Worklist` loop,
        // since MD may only act as a clobber for 1 of N MemoryLocations.
        FoundClobber = FoundClobber || MSSA.isLiveOnEntryDef(MD);
        if (!FoundClobber) {
          if (instructionClobbersQuery(MD, MAP.second, Query.Inst, AA))
            FoundClobber = true;
        }
      }
      break;
    }

    // We should never hit liveOnEntry, unless it's the clobber.
    assert(!MSSA.isLiveOnEntryDef(MA) && "Hit liveOnEntry before clobber?")(static_cast <bool> (!MSSA.isLiveOnEntryDef(MA) &&
 "Hit liveOnEntry before clobber?") ? void (0) : __assert_fail
 ("!MSSA.isLiveOnEntryDef(MA) && \"Hit liveOnEntry before clobber?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 442, __extension__ __PRETTY_FUNCTION__
));

    if (const auto *MD = dyn_cast<MemoryDef>(MA)) {
      // If Start is a Def, skip self.
      if (MD == Start)
        continue;

      assert(!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) &&(static_cast <bool> (!instructionClobbersQuery(MD, MAP.
second, Query.Inst, AA) && "Found clobber before reaching ClobberAt!"
) ? void (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) && \"Found clobber before reaching ClobberAt!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 450, __extension__ __PRETTY_FUNCTION__
))
             "Found clobber before reaching ClobberAt!")(static_cast <bool> (!instructionClobbersQuery(MD, MAP.
second, Query.Inst, AA) && "Found clobber before reaching ClobberAt!"
) ? void (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) && \"Found clobber before reaching ClobberAt!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 450, __extension__ __PRETTY_FUNCTION__
));
      continue;
    }

    if (const auto *MU = dyn_cast<MemoryUse>(MA)) {
      (void)MU;
      assert (MU == Start &&(static_cast <bool> (MU == Start && "Can only find use in def chain if Start is a use"
) ? void (0) : __assert_fail ("MU == Start && \"Can only find use in def chain if Start is a use\""
, "llvm/lib/Analysis/MemorySSA.cpp", 457, __extension__ __PRETTY_FUNCTION__
))
              "Can only find use in def chain if Start is a use")(static_cast <bool> (MU == Start && "Can only find use in def chain if Start is a use"
) ? void (0) : __assert_fail ("MU == Start && \"Can only find use in def chain if Start is a use\""
, "llvm/lib/Analysis/MemorySSA.cpp", 457, __extension__ __PRETTY_FUNCTION__
));
      continue;
    }

    assert(isa<MemoryPhi>(MA))(static_cast <bool> (isa<MemoryPhi>(MA)) ? void (
0) : __assert_fail ("isa<MemoryPhi>(MA)", "llvm/lib/Analysis/MemorySSA.cpp"
, 461, __extension__ __PRETTY_FUNCTION__));

    // Add reachable phi predecessors
    for (auto ItB = upward_defs_begin(
                  {const_cast<MemoryAccess *>(MA), MAP.second},
                  MSSA.getDomTree()),
              ItE = upward_defs_end();
         ItB != ItE; ++ItB)
      if (MSSA.getDomTree().isReachableFromEntry(ItB.getPhiArgBlock()))
        Worklist.emplace_back(*ItB);
  }
}

// If the verify is done following an optimization, it's possible that
// ClobberAt was a conservative clobbering, that we can now infer is not a
// true clobbering access. Don't fail the verify if that's the case.
// We do have accesses that claim they're optimized, but could be optimized
// further. Updating all these can be expensive, so allow it for now (FIXME).
if (AllowImpreciseClobber)
  return;

// If ClobberAt is a MemoryPhi, we can assume something above it acted as a
// clobber. Otherwise, `ClobberAt` should've acted as a clobber at some point.
assert((isa<MemoryPhi>(ClobberAt) || FoundClobber) &&(static_cast <bool> ((isa<MemoryPhi>(ClobberAt) ||
 FoundClobber) && "ClobberAt never acted as a clobber"
) ? void (0) : __assert_fail ("(isa<MemoryPhi>(ClobberAt) || FoundClobber) && \"ClobberAt never acted as a clobber\""
, "llvm/lib/Analysis/MemorySSA.cpp", 485, __extension__ __PRETTY_FUNCTION__
))
       "ClobberAt never acted as a clobber")(static_cast <bool> ((isa<MemoryPhi>(ClobberAt) ||
 FoundClobber) && "ClobberAt never acted as a clobber"
) ? void (0) : __assert_fail ("(isa<MemoryPhi>(ClobberAt) || FoundClobber) && \"ClobberAt never acted as a clobber\""
, "llvm/lib/Analysis/MemorySSA.cpp", 485, __extension__ __PRETTY_FUNCTION__
));
486}

488namespace {

490/// Our algorithm for walking (and trying to optimize) clobbers, all wrapped up
491/// in one class.
492class ClobberWalker {
/// Save a few bytes by using unsigned instead of size_t.
using ListIndex = unsigned;

/// Represents a span of contiguous MemoryDefs, potentially ending in a
/// MemoryPhi.
struct DefPath {
  MemoryLocation Loc;
  // Note that, because we always walk in reverse, Last will always dominate
  // First. Also note that First and Last are inclusive.
  MemoryAccess *First;
  MemoryAccess *Last;
  std::optional<ListIndex> Previous;

  DefPath(const MemoryLocation &Loc, MemoryAccess *First, MemoryAccess *Last,
          std::optional<ListIndex> Previous)
      : Loc(Loc), First(First), Last(Last), Previous(Previous) {}

  DefPath(const MemoryLocation &Loc, MemoryAccess *Init,
          std::optional<ListIndex> Previous)
      : DefPath(Loc, Init, Init, Previous) {}
};

const MemorySSA &MSSA;
DominatorTree &DT;
BatchAAResults *AA;
UpwardsMemoryQuery *Query;
unsigned *UpwardWalkLimit;

// Phi optimization bookkeeping:
// List of DefPath to process during the current phi optimization walk.
SmallVector<DefPath, 32> Paths;
// List of visited <Access, Location> pairs; we can skip paths already
// visited with the same memory location.
DenseSet<ConstMemoryAccessPair> VisitedPhis;

/// Find the nearest def or phi that `From` can legally be optimized to.
const MemoryAccess *getWalkTarget(const MemoryPhi *From) const {
  assert(From->getNumOperands() && "Phi with no operands?")(static_cast <bool> (From->getNumOperands() &&
 "Phi with no operands?") ? void (0) : __assert_fail ("From->getNumOperands() && \"Phi with no operands?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 530, __extension__ __PRETTY_FUNCTION__
));

  BasicBlock *BB = From->getBlock();
  MemoryAccess *Result = MSSA.getLiveOnEntryDef();
  DomTreeNode *Node = DT.getNode(BB);
  while ((Node = Node->getIDom())) {
    auto *Defs = MSSA.getBlockDefs(Node->getBlock());
    if (Defs)
      return &*Defs->rbegin();
  }
  return Result;
}

/// Result of calling walkToPhiOrClobber.
struct UpwardsWalkResult {
  /// The "Result" of the walk. Either a clobber, the last thing we walked, or
  /// both. Include alias info when clobber found.
  MemoryAccess *Result;
  bool IsKnownClobber;
};

/// Walk to the next Phi or Clobber in the def chain starting at Desc.Last.
/// This will update Desc.Last as it walks. It will (optionally) also stop at
/// StopAt.
///
/// This does not test for whether StopAt is a clobber
UpwardsWalkResult
walkToPhiOrClobber(DefPath &Desc, const MemoryAccess *StopAt = nullptr,
                   const MemoryAccess *SkipStopAt = nullptr) const {
  assert(!isa<MemoryUse>(Desc.Last) && "Uses don't exist in my world")(static_cast <bool> (!isa<MemoryUse>(Desc.Last) &&
 "Uses don't exist in my world") ? void (0) : __assert_fail (
"!isa<MemoryUse>(Desc.Last) && \"Uses don't exist in my world\""
, "llvm/lib/Analysis/MemorySSA.cpp", 559, __extension__ __PRETTY_FUNCTION__
));
  assert(UpwardWalkLimit && "Need a valid walk limit")(static_cast <bool> (UpwardWalkLimit && "Need a valid walk limit"
) ? void (0) : __assert_fail ("UpwardWalkLimit && \"Need a valid walk limit\""
, "llvm/lib/Analysis/MemorySSA.cpp", 560, __extension__ __PRETTY_FUNCTION__
));
  bool LimitAlreadyReached = false;
  // (*UpwardWalkLimit) may be 0 here, due to the loop in tryOptimizePhi. Set
  // it to 1. This will not do any alias() calls. It either returns in the
  // first iteration in the loop below, or is set back to 0 if all def chains
  // are free of MemoryDefs.
  if (!*UpwardWalkLimit) {
    *UpwardWalkLimit = 1;
    LimitAlreadyReached = true;
  }

  for (MemoryAccess *Current : def_chain(Desc.Last)) {
    Desc.Last = Current;
    if (Current == StopAt || Current == SkipStopAt)
      return {Current, false};

    if (auto *MD = dyn_cast<MemoryDef>(Current)) {
      if (MSSA.isLiveOnEntryDef(MD))
        return {MD, true};

      if (!--*UpwardWalkLimit)
        return {Current, true};

      if (instructionClobbersQuery(MD, Desc.Loc, Query->Inst, *AA))
        return {MD, true};
    }
  }

  if (LimitAlreadyReached)
    *UpwardWalkLimit = 0;

  assert(isa<MemoryPhi>(Desc.Last) &&(static_cast <bool> (isa<MemoryPhi>(Desc.Last) &&
 "Ended at a non-clobber that's not a phi?") ? void (0) : __assert_fail
 ("isa<MemoryPhi>(Desc.Last) && \"Ended at a non-clobber that's not a phi?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 592, __extension__ __PRETTY_FUNCTION__
))
         "Ended at a non-clobber that's not a phi?")(static_cast <bool> (isa<MemoryPhi>(Desc.Last) &&
 "Ended at a non-clobber that's not a phi?") ? void (0) : __assert_fail
 ("isa<MemoryPhi>(Desc.Last) && \"Ended at a non-clobber that's not a phi?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 592, __extension__ __PRETTY_FUNCTION__
));
  return {Desc.Last, false};
}

void addSearches(MemoryPhi *Phi, SmallVectorImpl<ListIndex> &PausedSearches,
                 ListIndex PriorNode) {
  auto UpwardDefsBegin = upward_defs_begin({Phi, Paths[PriorNode].Loc}, DT);
  auto UpwardDefs = make_range(UpwardDefsBegin, upward_defs_end());
  for (const MemoryAccessPair &P : UpwardDefs) {
    PausedSearches.push_back(Paths.size());
    Paths.emplace_back(P.second, P.first, PriorNode);
  }
}

/// Represents a search that terminated after finding a clobber. This clobber
/// may or may not be present in the path of defs from LastNode..SearchStart,
/// since it may have been retrieved from cache.
struct TerminatedPath {
  MemoryAccess *Clobber;
  ListIndex LastNode;
};

/// Get an access that keeps us from optimizing to the given phi.
///
/// PausedSearches is an array of indices into the Paths array. Its incoming
/// value is the indices of searches that stopped at the last phi optimization
/// target. It's left in an unspecified state.
///
/// If this returns std::nullopt, NewPaused is a vector of searches that
/// terminated at StopWhere. Otherwise, NewPaused is left in an unspecified
/// state.
std::optional<TerminatedPath>
getBlockingAccess(const MemoryAccess *StopWhere,
                  SmallVectorImpl<ListIndex> &PausedSearches,
                  SmallVectorImpl<ListIndex> &NewPaused,
                  SmallVectorImpl<TerminatedPath> &Terminated) {
  assert(!PausedSearches.empty() && "No searches to continue?")(static_cast <bool> (!PausedSearches.empty() &&
 "No searches to continue?") ? void (0) : __assert_fail ("!PausedSearches.empty() && \"No searches to continue?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 628, __extension__ __PRETTY_FUNCTION__
));

  // BFS vs DFS really doesn't make a difference here, so just do a DFS with
  // PausedSearches as our stack.
  while (!PausedSearches.empty()) {
    ListIndex PathIndex = PausedSearches.pop_back_val();
    DefPath &Node = Paths[PathIndex];

    // If we've already visited this path with this MemoryLocation, we don't
    // need to do so again.
    //
    // NOTE: That we just drop these paths on the ground makes caching
    // behavior sporadic. e.g. given a diamond:
    //  A
    // B C
    //  D
    //
    // ...If we walk D, B, A, C, we'll only cache the result of phi
    // optimization for A, B, and D; C will be skipped because it dies here.
    // This arguably isn't the worst thing ever, since:
    //   - We generally query things in a top-down order, so if we got below D
    //     without needing cache entries for {C, MemLoc}, then chances are
    //     that those cache entries would end up ultimately unused.
    //   - We still cache things for A, so C only needs to walk up a bit.
    // If this behavior becomes problematic, we can fix without a ton of extra
    // work.
    if (!VisitedPhis.insert({Node.Last, Node.Loc}).second)
      continue;

    const MemoryAccess *SkipStopWhere = nullptr;
    if (Query->SkipSelfAccess && Node.Loc == Query->StartingLoc) {
      assert(isa<MemoryDef>(Query->OriginalAccess))(static_cast <bool> (isa<MemoryDef>(Query->OriginalAccess
)) ? void (0) : __assert_fail ("isa<MemoryDef>(Query->OriginalAccess)"
, "llvm/lib/Analysis/MemorySSA.cpp", 659, __extension__ __PRETTY_FUNCTION__
));
      SkipStopWhere = Query->OriginalAccess;
    }

    UpwardsWalkResult Res = walkToPhiOrClobber(Node,
                                               /*StopAt=*/StopWhere,
                                               /*SkipStopAt=*/SkipStopWhere);
    if (Res.IsKnownClobber) {
      assert(Res.Result != StopWhere && Res.Result != SkipStopWhere)(static_cast <bool> (Res.Result != StopWhere &&
 Res.Result != SkipStopWhere) ? void (0) : __assert_fail ("Res.Result != StopWhere && Res.Result != SkipStopWhere"
, "llvm/lib/Analysis/MemorySSA.cpp", 667, __extension__ __PRETTY_FUNCTION__
));

      // If this wasn't a cache hit, we hit a clobber when walking. That's a
      // failure.
      TerminatedPath Term{Res.Result, PathIndex};
      if (!MSSA.dominates(Res.Result, StopWhere))
        return Term;

      // Otherwise, it's a valid thing to potentially optimize to.
      Terminated.push_back(Term);
      continue;
    }

    if (Res.Result == StopWhere || Res.Result == SkipStopWhere) {
      // We've hit our target. Save this path off for if we want to continue
      // walking. If we are in the mode of skipping the OriginalAccess, and
      // we've reached back to the OriginalAccess, do not save path, we've
      // just looped back to self.
      if (Res.Result != SkipStopWhere)
        NewPaused.push_back(PathIndex);
      continue;
    }

    assert(!MSSA.isLiveOnEntryDef(Res.Result) && "liveOnEntry is a clobber")(static_cast <bool> (!MSSA.isLiveOnEntryDef(Res.Result)
 && "liveOnEntry is a clobber") ? void (0) : __assert_fail
 ("!MSSA.isLiveOnEntryDef(Res.Result) && \"liveOnEntry is a clobber\""
, "llvm/lib/Analysis/MemorySSA.cpp", 690, __extension__ __PRETTY_FUNCTION__
));
    addSearches(cast<MemoryPhi>(Res.Result), PausedSearches, PathIndex);
  }

  return std::nullopt;
}

template <typename T, typename Walker>
struct generic_def_path_iterator
    : public iterator_facade_base<generic_def_path_iterator<T, Walker>,
                                  std::forward_iterator_tag, T *> {
  generic_def_path_iterator() = default;
  generic_def_path_iterator(Walker *W, ListIndex N) : W(W), N(N) {}

  T &operator*() const { return curNode(); }

  generic_def_path_iterator &operator++() {
    N = curNode().Previous;
    return *this;
  }

  bool operator==(const generic_def_path_iterator &O) const {
    if (N.has_value() != O.N.has_value())
      return false;
    return !N || *N == *O.N;
  }

private:
  T &curNode() const { return W->Paths[*N]; }

  Walker *W = nullptr;
  std::optional<ListIndex> N;
};

using def_path_iterator = generic_def_path_iterator<DefPath, ClobberWalker>;
using const_def_path_iterator =
    generic_def_path_iterator<const DefPath, const ClobberWalker>;

iterator_range<def_path_iterator> def_path(ListIndex From) {
  return make_range(def_path_iterator(this, From), def_path_iterator());
}

iterator_range<const_def_path_iterator> const_def_path(ListIndex From) const {
  return make_range(const_def_path_iterator(this, From),
                    const_def_path_iterator());
}

struct OptznResult {
  /// The path that contains our result.
  TerminatedPath PrimaryClobber;
  /// The paths that we can legally cache back from, but that aren't
  /// necessarily the result of the Phi optimization.
  SmallVector<TerminatedPath, 4> OtherClobbers;
};

ListIndex defPathIndex(const DefPath &N) const {
  // The assert looks nicer if we don't need to do &N
  const DefPath *NP = &N;
  assert(!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() &&(static_cast <bool> (!Paths.empty() && NP >=
 &Paths.front() && NP <= &Paths.back() &&
 "Out of bounds DefPath!") ? void (0) : __assert_fail ("!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && \"Out of bounds DefPath!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 749, __extension__ __PRETTY_FUNCTION__
))
         "Out of bounds DefPath!")(static_cast <bool> (!Paths.empty() && NP >=
 &Paths.front() && NP <= &Paths.back() &&
 "Out of bounds DefPath!") ? void (0) : __assert_fail ("!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && \"Out of bounds DefPath!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 749, __extension__ __PRETTY_FUNCTION__
));
  return NP - &Paths.front();
}

/// Try to optimize a phi as best as we can. Returns a SmallVector of Paths
/// that act as legal clobbers. Note that this won't return *all* clobbers.
///
/// Phi optimization algorithm tl;dr:
///   - Find the earliest def/phi, A, we can optimize to
///   - Find if all paths from the starting memory access ultimately reach A
///     - If not, optimization isn't possible.
///     - Otherwise, walk from A to another clobber or phi, A'.
///       - If A' is a def, we're done.
///       - If A' is a phi, try to optimize it.
///
/// A path is a series of {MemoryAccess, MemoryLocation} pairs. A path
/// terminates when a MemoryAccess that clobbers said MemoryLocation is found.
OptznResult tryOptimizePhi(MemoryPhi *Phi, MemoryAccess *Start,
                           const MemoryLocation &Loc) {
  assert(Paths.empty() && VisitedPhis.empty() &&(static_cast <bool> (Paths.empty() && VisitedPhis
.empty() && "Reset the optimization state.") ? void (
0) : __assert_fail ("Paths.empty() && VisitedPhis.empty() && \"Reset the optimization state.\""
, "llvm/lib/Analysis/MemorySSA.cpp", 769, __extension__ __PRETTY_FUNCTION__
))
         "Reset the optimization state.")(static_cast <bool> (Paths.empty() && VisitedPhis
.empty() && "Reset the optimization state.") ? void (
0) : __assert_fail ("Paths.empty() && VisitedPhis.empty() && \"Reset the optimization state.\""
, "llvm/lib/Analysis/MemorySSA.cpp", 769, __extension__ __PRETTY_FUNCTION__
));

  Paths.emplace_back(Loc, Start, Phi, std::nullopt);
  // Stores how many "valid" optimization nodes we had prior to calling
  // addSearches/getBlockingAccess. Necessary for caching if we had a blocker.
  auto PriorPathsSize = Paths.size();

  SmallVector<ListIndex, 16> PausedSearches;
  SmallVector<ListIndex, 8> NewPaused;
  SmallVector<TerminatedPath, 4> TerminatedPaths;

  addSearches(Phi, PausedSearches, 0);

  // Moves the TerminatedPath with the "most dominated" Clobber to the end of
  // Paths.
  auto MoveDominatedPathToEnd = [&](SmallVectorImpl<TerminatedPath> &Paths) {
    assert(!Paths.empty() && "Need a path to move")(static_cast <bool> (!Paths.empty() && "Need a path to move"
) ? void (0) : __assert_fail ("!Paths.empty() && \"Need a path to move\""
, "llvm/lib/Analysis/MemorySSA.cpp", 785, __extension__ __PRETTY_FUNCTION__
));
    auto Dom = Paths.begin();
    for (auto I = std::next(Dom), E = Paths.end(); I != E; ++I)
      if (!MSSA.dominates(I->Clobber, Dom->Clobber))
        Dom = I;
    auto Last = Paths.end() - 1;
    if (Last != Dom)
      std::iter_swap(Last, Dom);
  };

  MemoryPhi *Current = Phi;
  while (true) {
    assert(!MSSA.isLiveOnEntryDef(Current) &&(static_cast <bool> (!MSSA.isLiveOnEntryDef(Current) &&
 "liveOnEntry wasn't treated as a clobber?") ? void (0) : __assert_fail
 ("!MSSA.isLiveOnEntryDef(Current) && \"liveOnEntry wasn't treated as a clobber?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 798, __extension__ __PRETTY_FUNCTION__
))
           "liveOnEntry wasn't treated as a clobber?")(static_cast <bool> (!MSSA.isLiveOnEntryDef(Current) &&
 "liveOnEntry wasn't treated as a clobber?") ? void (0) : __assert_fail
 ("!MSSA.isLiveOnEntryDef(Current) && \"liveOnEntry wasn't treated as a clobber?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 798, __extension__ __PRETTY_FUNCTION__
));

    const auto *Target = getWalkTarget(Current);
    // If a TerminatedPath doesn't dominate Target, then it wasn't a legal
    // optimization for the prior phi.
    assert(all_of(TerminatedPaths, [&](const TerminatedPath &P) {(static_cast <bool> (all_of(TerminatedPaths, [&](const
 TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target
); })) ? void (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })"
, "llvm/lib/Analysis/MemorySSA.cpp", 805, __extension__ __PRETTY_FUNCTION__
))
      return MSSA.dominates(P.Clobber, Target);(static_cast <bool> (all_of(TerminatedPaths, [&](const
 TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target
); })) ? void (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })"
, "llvm/lib/Analysis/MemorySSA.cpp", 805, __extension__ __PRETTY_FUNCTION__
))
    }))(static_cast <bool> (all_of(TerminatedPaths, [&](const
 TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target
); })) ? void (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })"
, "llvm/lib/Analysis/MemorySSA.cpp", 805, __extension__ __PRETTY_FUNCTION__
));

    // FIXME: This is broken, because the Blocker may be reported to be
    // liveOnEntry, and we'll happily wait for that to disappear (read: never)
    // For the moment, this is fine, since we do nothing with blocker info.
    if (std::optional<TerminatedPath> Blocker = getBlockingAccess(
            Target, PausedSearches, NewPaused, TerminatedPaths)) {

      // Find the node we started at. We can't search based on N->Last, since
      // we may have gone around a loop with a different MemoryLocation.
      auto Iter = find_if(def_path(Blocker->LastNode), [&](const DefPath &N) {
        return defPathIndex(N) < PriorPathsSize;
      });
      assert(Iter != def_path_iterator())(static_cast <bool> (Iter != def_path_iterator()) ? void
 (0) : __assert_fail ("Iter != def_path_iterator()", "llvm/lib/Analysis/MemorySSA.cpp"
, 818, __extension__ __PRETTY_FUNCTION__));

      DefPath &CurNode = *Iter;
      assert(CurNode.Last == Current)(static_cast <bool> (CurNode.Last == Current) ? void (0
) : __assert_fail ("CurNode.Last == Current", "llvm/lib/Analysis/MemorySSA.cpp"
, 821, __extension__ __PRETTY_FUNCTION__));

      // Two things:
      // A. We can't reliably cache all of NewPaused back. Consider a case
      //    where we have two paths in NewPaused; one of which can't optimize
      //    above this phi, whereas the other can. If we cache the second path
      //    back, we'll end up with suboptimal cache entries. We can handle
      //    cases like this a bit better when we either try to find all
      //    clobbers that block phi optimization, or when our cache starts
      //    supporting unfinished searches.
      // B. We can't reliably cache TerminatedPaths back here without doing
      //    extra checks; consider a case like:
      //       T
      //      / \
      //     D   C
      //      \ /
      //       S
      //    Where T is our target, C is a node with a clobber on it, D is a
      //    diamond (with a clobber *only* on the left or right node, N), and
      //    S is our start. Say we walk to D, through the node opposite N
      //    (read: ignoring the clobber), and see a cache entry in the top
      //    node of D. That cache entry gets put into TerminatedPaths. We then
      //    walk up to C (N is later in our worklist), find the clobber, and
      //    quit. If we append TerminatedPaths to OtherClobbers, we'll cache
      //    the bottom part of D to the cached clobber, ignoring the clobber
      //    in N. Again, this problem goes away if we start tracking all
      //    blockers for a given phi optimization.
      TerminatedPath Result{CurNode.Last, defPathIndex(CurNode)};
      return {Result, {}};
    }

    // If there's nothing left to search, then all paths led to valid clobbers
    // that we got from our cache; pick the nearest to the start, and allow
    // the rest to be cached back.
    if (NewPaused.empty()) {
      MoveDominatedPathToEnd(TerminatedPaths);
      TerminatedPath Result = TerminatedPaths.pop_back_val();
      return {Result, std::move(TerminatedPaths)};
    }

    MemoryAccess *DefChainEnd = nullptr;
    SmallVector<TerminatedPath, 4> Clobbers;
    for (ListIndex Paused : NewPaused) {
      UpwardsWalkResult WR = walkToPhiOrClobber(Paths[Paused]);
      if (WR.IsKnownClobber)
        Clobbers.push_back({WR.Result, Paused});
      else
        // Micro-opt: If we hit the end of the chain, save it.
        DefChainEnd = WR.Result;
    }

    if (!TerminatedPaths.empty()) {
      // If we couldn't find the dominating phi/liveOnEntry in the above loop,
      // do it now.
      if (!DefChainEnd)
        for (auto *MA : def_chain(const_cast<MemoryAccess *>(Target)))
          DefChainEnd = MA;
      assert(DefChainEnd && "Failed to find dominating phi/liveOnEntry")(static_cast <bool> (DefChainEnd && "Failed to find dominating phi/liveOnEntry"
) ? void (0) : __assert_fail ("DefChainEnd && \"Failed to find dominating phi/liveOnEntry\""
, "llvm/lib/Analysis/MemorySSA.cpp", 878, __extension__ __PRETTY_FUNCTION__
));

      // If any of the terminated paths don't dominate the phi we'll try to
      // optimize, we need to figure out what they are and quit.
      const BasicBlock *ChainBB = DefChainEnd->getBlock();
      for (const TerminatedPath &TP : TerminatedPaths) {
        // Because we know that DefChainEnd is as "high" as we can go, we
        // don't need local dominance checks; BB dominance is sufficient.
        if (DT.dominates(ChainBB, TP.Clobber->getBlock()))
          Clobbers.push_back(TP);
      }
    }

    // If we have clobbers in the def chain, find the one closest to Current
    // and quit.
    if (!Clobbers.empty()) {
      MoveDominatedPathToEnd(Clobbers);
      TerminatedPath Result = Clobbers.pop_back_val();
      return {Result, std::move(Clobbers)};
    }

    assert(all_of(NewPaused,(static_cast <bool> (all_of(NewPaused, [&](ListIndex
 I) { return Paths[I].Last == DefChainEnd; })) ? void (0) : __assert_fail
 ("all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })"
, "llvm/lib/Analysis/MemorySSA.cpp", 900, __extension__ __PRETTY_FUNCTION__
))
                  [&](ListIndex I) { return Paths[I].Last == DefChainEnd; }))(static_cast <bool> (all_of(NewPaused, [&](ListIndex
 I) { return Paths[I].Last == DefChainEnd; })) ? void (0) : __assert_fail
 ("all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })"
, "llvm/lib/Analysis/MemorySSA.cpp", 900, __extension__ __PRETTY_FUNCTION__
));

    // Because liveOnEntry is a clobber, this must be a phi.
    auto *DefChainPhi = cast<MemoryPhi>(DefChainEnd);

    PriorPathsSize = Paths.size();
    PausedSearches.clear();
    for (ListIndex I : NewPaused)
      addSearches(DefChainPhi, PausedSearches, I);
    NewPaused.clear();

    Current = DefChainPhi;
  }
}

void verifyOptResult(const OptznResult &R) const {
  assert(all_of(R.OtherClobbers, [&](const TerminatedPath &P) {(static_cast <bool> (all_of(R.OtherClobbers, [&](const
 TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.
PrimaryClobber.Clobber); })) ? void (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })"
, "llvm/lib/Analysis/MemorySSA.cpp", 918, __extension__ __PRETTY_FUNCTION__
))
    return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber);(static_cast <bool> (all_of(R.OtherClobbers, [&](const
 TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.
PrimaryClobber.Clobber); })) ? void (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })"
, "llvm/lib/Analysis/MemorySSA.cpp", 918, __extension__ __PRETTY_FUNCTION__
))
  }))(static_cast <bool> (all_of(R.OtherClobbers, [&](const
 TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.
PrimaryClobber.Clobber); })) ? void (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })"
, "llvm/lib/Analysis/MemorySSA.cpp", 918, __extension__ __PRETTY_FUNCTION__
));
}

void resetPhiOptznState() {
  Paths.clear();
  VisitedPhis.clear();
}

926public:
ClobberWalker(const MemorySSA &MSSA, DominatorTree &DT)
    : MSSA(MSSA), DT(DT) {}

/// Finds the nearest clobber for the given query, optimizing phis if
/// possible.
MemoryAccess *findClobber(BatchAAResults &BAA, MemoryAccess *Start,
                          UpwardsMemoryQuery &Q, unsigned &UpWalkLimit) {
  AA = &BAA;
  Query = &Q;
  UpwardWalkLimit = &UpWalkLimit;
  // Starting limit must be > 0.
  if (!UpWalkLimit)
    UpWalkLimit++;

  MemoryAccess *Current = Start;
  // This walker pretends uses don't exist. If we're handed one, silently grab
  // its def. (This has the nice side-effect of ensuring we never cache uses)
  if (auto *MU = dyn_cast<MemoryUse>(Start))
    Current = MU->getDefiningAccess();

  DefPath FirstDesc(Q.StartingLoc, Current, Current, std::nullopt);
  // Fast path for the overly-common case (no crazy phi optimization
  // necessary)
  UpwardsWalkResult WalkResult = walkToPhiOrClobber(FirstDesc);
  MemoryAccess *Result;
  if (WalkResult.IsKnownClobber) {
    Result = WalkResult.Result;
  } else {
    OptznResult OptRes = tryOptimizePhi(cast<MemoryPhi>(FirstDesc.Last),
                                        Current, Q.StartingLoc);
    verifyOptResult(OptRes);
    resetPhiOptznState();
    Result = OptRes.PrimaryClobber.Clobber;
  }

962#ifdef EXPENSIVE_CHECKS
  if (!Q.SkipSelfAccess && *UpwardWalkLimit > 0)
    checkClobberSanity(Current, Result, Q.StartingLoc, MSSA, Q, BAA);
965#endif
  return Result;
}
968};

970struct RenamePassData {
DomTreeNode *DTN;
DomTreeNode::const_iterator ChildIt;
MemoryAccess *IncomingVal;

RenamePassData(DomTreeNode *D, DomTreeNode::const_iterator It,
               MemoryAccess *M)
    : DTN(D), ChildIt(It), IncomingVal(M) {}

void swap(RenamePassData &RHS) {
  std::swap(DTN, RHS.DTN);
  std::swap(ChildIt, RHS.ChildIt);
  std::swap(IncomingVal, RHS.IncomingVal);
}
984};

986} // end anonymous namespace

988namespace llvm {

990class MemorySSA::ClobberWalkerBase {
ClobberWalker Walker;
MemorySSA *MSSA;

994public:
ClobberWalkerBase(MemorySSA *M, DominatorTree *D) : Walker(*M, *D), MSSA(M) {}

MemoryAccess *getClobberingMemoryAccessBase(MemoryAccess *,
                                            const MemoryLocation &,
                                            BatchAAResults &, unsigned &);
// Third argument (bool), defines whether the clobber search should skip the
// original queried access. If true, there will be a follow-up query searching
// for a clobber access past "self". Note that the Optimized access is not
// updated if a new clobber is found by this SkipSelf search. If this
// additional query becomes heavily used we may decide to cache the result.
// Walker instantiations will decide how to set the SkipSelf bool.
MemoryAccess *getClobberingMemoryAccessBase(MemoryAccess *, BatchAAResults &,
                                            unsigned &, bool,
                                            bool UseInvariantGroup = true);
1009};

1011/// A MemorySSAWalker that does AA walks to disambiguate accesses. It no
1012/// longer does caching on its own, but the name has been retained for the
1013/// moment.
1014class MemorySSA::CachingWalker final : public MemorySSAWalker {
ClobberWalkerBase *Walker;

1017public:
CachingWalker(MemorySSA *M, ClobberWalkerBase *W)
    : MemorySSAWalker(M), Walker(W) {}
~CachingWalker() override = default;

using MemorySSAWalker::getClobberingMemoryAccess;

MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA, BatchAAResults &BAA,
                                        unsigned &UWL) {
  return Walker->getClobberingMemoryAccessBase(MA, BAA, UWL, false);
}
MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA,
                                        const MemoryLocation &Loc,
                                        BatchAAResults &BAA, unsigned &UWL) {
  return Walker->getClobberingMemoryAccessBase(MA, Loc, BAA, UWL);
}
// This method is not accessible outside of this file.
MemoryAccess *getClobberingMemoryAccessWithoutInvariantGroup(
    MemoryAccess *MA, BatchAAResults &BAA, unsigned &UWL) {
  return Walker->getClobberingMemoryAccessBase(MA, BAA, UWL, false, false);
}

MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA,
                                        BatchAAResults &BAA) override {
  unsigned UpwardWalkLimit = MaxCheckLimit;
  return getClobberingMemoryAccess(MA, BAA, UpwardWalkLimit);
}
MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA,
                                        const MemoryLocation &Loc,
                                        BatchAAResults &BAA) override {
  unsigned UpwardWalkLimit = MaxCheckLimit;
  return getClobberingMemoryAccess(MA, Loc, BAA, UpwardWalkLimit);
}

void invalidateInfo(MemoryAccess *MA) override {
  if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
    MUD->resetOptimized();
}
1055};

1057class MemorySSA::SkipSelfWalker final : public MemorySSAWalker {
ClobberWalkerBase *Walker;

1060public:
SkipSelfWalker(MemorySSA *M, ClobberWalkerBase *W)
    : MemorySSAWalker(M), Walker(W) {}
~SkipSelfWalker() override = default;

using MemorySSAWalker::getClobberingMemoryAccess;

MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA, BatchAAResults &BAA,
                                        unsigned &UWL) {
  return Walker->getClobberingMemoryAccessBase(MA, BAA, UWL, true);
}
MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA,
                                        const MemoryLocation &Loc,
                                        BatchAAResults &BAA, unsigned &UWL) {
  return Walker->getClobberingMemoryAccessBase(MA, Loc, BAA, UWL);
}

MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA,
                                        BatchAAResults &BAA) override {
  unsigned UpwardWalkLimit = MaxCheckLimit;
  return getClobberingMemoryAccess(MA, BAA, UpwardWalkLimit);
}
MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA,
                                        const MemoryLocation &Loc,
                                        BatchAAResults &BAA) override {
  unsigned UpwardWalkLimit = MaxCheckLimit;
  return getClobberingMemoryAccess(MA, Loc, BAA, UpwardWalkLimit);
}

void invalidateInfo(MemoryAccess *MA) override {
  if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
    MUD->resetOptimized();
}
1093};

1095} // end namespace llvm

1097void MemorySSA::renameSuccessorPhis(BasicBlock *BB, MemoryAccess *IncomingVal,
                                  bool RenameAllUses) {
// Pass through values to our successors
for (const BasicBlock *S : successors(BB)) {
  auto It = PerBlockAccesses.find(S);
  // Rename the phi nodes in our successor block
  if (It == PerBlockAccesses.end() || !isa<MemoryPhi>(It->second->front()))
    continue;
  AccessList *Accesses = It->second.get();
  auto *Phi = cast<MemoryPhi>(&Accesses->front());
  if (RenameAllUses) {
    bool ReplacementDone = false;
    for (unsigned I = 0, E = Phi->getNumIncomingValues(); I != E; ++I)
      if (Phi->getIncomingBlock(I) == BB) {
        Phi->setIncomingValue(I, IncomingVal);
        ReplacementDone = true;
      }
    (void) ReplacementDone;
    assert(ReplacementDone && "Incomplete phi during partial rename")(static_cast <bool> (ReplacementDone && "Incomplete phi during partial rename"
) ? void (0) : __assert_fail ("ReplacementDone && \"Incomplete phi during partial rename\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1115, __extension__ __PRETTY_FUNCTION__
));
  } else
    Phi->addIncoming(IncomingVal, BB);
}
1119}

1121/// Rename a single basic block into MemorySSA form.
1122/// Uses the standard SSA renaming algorithm.
1123/// \returns The new incoming value.
1124MemoryAccess *MemorySSA::renameBlock(BasicBlock *BB, MemoryAccess *IncomingVal,
                                   bool RenameAllUses) {
auto It = PerBlockAccesses.find(BB);
// Skip most processing if the list is empty.
if (It != PerBlockAccesses.end()) {
  AccessList *Accesses = It->second.get();
  for (MemoryAccess &L : *Accesses) {
    if (MemoryUseOrDef *MUD = dyn_cast<MemoryUseOrDef>(&L)) {
      if (MUD->getDefiningAccess() == nullptr || RenameAllUses)
        MUD->setDefiningAccess(IncomingVal);
      if (isa<MemoryDef>(&L))
        IncomingVal = &L;
    } else {
      IncomingVal = &L;
    }
  }
}
return IncomingVal;
1142}

1144/// This is the standard SSA renaming algorithm.
1145///
1146/// We walk the dominator tree in preorder, renaming accesses, and then filling
1147/// in phi nodes in our successors.
1148void MemorySSA::renamePass(DomTreeNode *Root, MemoryAccess *IncomingVal,
                         SmallPtrSetImpl<BasicBlock *> &Visited,
                         bool SkipVisited, bool RenameAllUses) {
assert(Root && "Trying to rename accesses in an unreachable block")(static_cast <bool> (Root && "Trying to rename accesses in an unreachable block"
) ? void (0) : __assert_fail ("Root && \"Trying to rename accesses in an unreachable block\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1151, __extension__ __PRETTY_FUNCTION__
));

SmallVector<RenamePassData, 32> WorkStack;
// Skip everything if we already renamed this block and we are skipping.
// Note: You can't sink this into the if, because we need it to occur
// regardless of whether we skip blocks or not.
bool AlreadyVisited = !Visited.insert(Root->getBlock()).second;
if (SkipVisited && AlreadyVisited)
  return;

IncomingVal = renameBlock(Root->getBlock(), IncomingVal, RenameAllUses);
renameSuccessorPhis(Root->getBlock(), IncomingVal, RenameAllUses);
WorkStack.push_back({Root, Root->begin(), IncomingVal});

while (!WorkStack.empty()) {
  DomTreeNode *Node = WorkStack.back().DTN;
  DomTreeNode::const_iterator ChildIt = WorkStack.back().ChildIt;
  IncomingVal = WorkStack.back().IncomingVal;

  if (ChildIt == Node->end()) {
    WorkStack.pop_back();
  } else {
    DomTreeNode *Child = *ChildIt;
    ++WorkStack.back().ChildIt;
    BasicBlock *BB = Child->getBlock();
    // Note: You can't sink this into the if, because we need it to occur
    // regardless of whether we skip blocks or not.
    AlreadyVisited = !Visited.insert(BB).second;
    if (SkipVisited && AlreadyVisited) {
      // We already visited this during our renaming, which can happen when
      // being asked to rename multiple blocks. Figure out the incoming val,
      // which is the last def.
      // Incoming value can only change if there is a block def, and in that
      // case, it's the last block def in the list.
      if (auto *BlockDefs = getWritableBlockDefs(BB))
        IncomingVal = &*BlockDefs->rbegin();
    } else
      IncomingVal = renameBlock(BB, IncomingVal, RenameAllUses);
    renameSuccessorPhis(BB, IncomingVal, RenameAllUses);
    WorkStack.push_back({Child, Child->begin(), IncomingVal});
  }
}
1193}

1195/// This handles unreachable block accesses by deleting phi nodes in
1196/// unreachable blocks, and marking all other unreachable MemoryAccess's as
1197/// being uses of the live on entry definition.
1198void MemorySSA::markUnreachableAsLiveOnEntry(BasicBlock *BB) {
assert(!DT->isReachableFromEntry(BB) &&(static_cast <bool> (!DT->isReachableFromEntry(BB) &&
 "Reachable block found while handling unreachable blocks") ?
 void (0) : __assert_fail ("!DT->isReachableFromEntry(BB) && \"Reachable block found while handling unreachable blocks\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1200, __extension__ __PRETTY_FUNCTION__
))
       "Reachable block found while handling unreachable blocks")(static_cast <bool> (!DT->isReachableFromEntry(BB) &&
 "Reachable block found while handling unreachable blocks") ?
 void (0) : __assert_fail ("!DT->isReachableFromEntry(BB) && \"Reachable block found while handling unreachable blocks\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1200, __extension__ __PRETTY_FUNCTION__
));

// Make sure phi nodes in our reachable successors end up with a
// LiveOnEntryDef for our incoming edge, even though our block is forward
// unreachable.  We could just disconnect these blocks from the CFG fully,
// but we do not right now.
for (const BasicBlock *S : successors(BB)) {
  if (!DT->isReachableFromEntry(S))
    continue;
  auto It = PerBlockAccesses.find(S);
  // Rename the phi nodes in our successor block
  if (It == PerBlockAccesses.end() || !isa<MemoryPhi>(It->second->front()))
    continue;
  AccessList *Accesses = It->second.get();
  auto *Phi = cast<MemoryPhi>(&Accesses->front());
  Phi->addIncoming(LiveOnEntryDef.get(), BB);
}

auto It = PerBlockAccesses.find(BB);
if (It == PerBlockAccesses.end())
  return;

auto &Accesses = It->second;
for (auto AI = Accesses->begin(), AE = Accesses->end(); AI != AE;) {
  auto Next = std::next(AI);
  // If we have a phi, just remove it. We are going to replace all
  // users with live on entry.
  if (auto *UseOrDef = dyn_cast<MemoryUseOrDef>(AI))
    UseOrDef->setDefiningAccess(LiveOnEntryDef.get());
  else
    Accesses->erase(AI);
  AI = Next;
}
1233}

1235MemorySSA::MemorySSA(Function &Func, AliasAnalysis *AA, DominatorTree *DT)
  : DT(DT), F(Func), LiveOnEntryDef(nullptr), Walker(nullptr),
    SkipWalker(nullptr) {
// Build MemorySSA using a batch alias analysis. This reuses the internal
// state that AA collects during an alias()/getModRefInfo() call. This is
// safe because there are no CFG changes while building MemorySSA and can
// significantly reduce the time spent by the compiler in AA, because we will
// make queries about all the instructions in the Function.
assert(AA && "No alias analysis?")(static_cast <bool> (AA && "No alias analysis?"
) ? void (0) : __assert_fail ("AA && \"No alias analysis?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1243, __extension__ __PRETTY_FUNCTION__
));
BatchAAResults BatchAA(*AA);
buildMemorySSA(BatchAA);
// Intentionally leave AA to nullptr while building so we don't accidently
// use non-batch AliasAnalysis.
this->AA = AA;
// Also create the walker here.
getWalker();
1251}

1253MemorySSA::~MemorySSA() {
// Drop all our references
for (const auto &Pair : PerBlockAccesses)
  for (MemoryAccess &MA : *Pair.second)
    MA.dropAllReferences();
1258}

1260MemorySSA::AccessList *MemorySSA::getOrCreateAccessList(const BasicBlock *BB) {
auto Res = PerBlockAccesses.insert(std::make_pair(BB, nullptr));

if (Res.second)
  Res.first->second = std::make_unique<AccessList>();
return Res.first->second.get();
1266}

1268MemorySSA::DefsList *MemorySSA::getOrCreateDefsList(const BasicBlock *BB) {
auto Res = PerBlockDefs.insert(std::make_pair(BB, nullptr));

if (Res.second)
  Res.first->second = std::make_unique<DefsList>();
return Res.first->second.get();
1274}

1276namespace llvm {

1278/// This class is a batch walker of all MemoryUse's in the program, and points
1279/// their defining access at the thing that actually clobbers them.  Because it
1280/// is a batch walker that touches everything, it does not operate like the
1281/// other walkers.  This walker is basically performing a top-down SSA renaming
1282/// pass, where the version stack is used as the cache.  This enables it to be
1283/// significantly more time and memory efficient than using the regular walker,
1284/// which is walking bottom-up.
1285class MemorySSA::OptimizeUses {
1286public:
OptimizeUses(MemorySSA *MSSA, CachingWalker *Walker, BatchAAResults *BAA,
             DominatorTree *DT)
    : MSSA(MSSA), Walker(Walker), AA(BAA), DT(DT) {}

void optimizeUses();

1293private:
/// This represents where a given memorylocation is in the stack.
struct MemlocStackInfo {
  // This essentially is keeping track of versions of the stack. Whenever
  // the stack changes due to pushes or pops, these versions increase.
  unsigned long StackEpoch;
  unsigned long PopEpoch;
  // This is the lower bound of places on the stack to check. It is equal to
  // the place the last stack walk ended.
  // Note: Correctness depends on this being initialized to 0, which densemap
  // does
  unsigned long LowerBound;
  const BasicBlock *LowerBoundBlock;
  // This is where the last walk for this memory location ended.
  unsigned long LastKill;
  bool LastKillValid;
};

void optimizeUsesInBlock(const BasicBlock *, unsigned long &, unsigned long &,
                         SmallVectorImpl<MemoryAccess *> &,
                         DenseMap<MemoryLocOrCall, MemlocStackInfo> &);

MemorySSA *MSSA;
CachingWalker *Walker;
BatchAAResults *AA;
DominatorTree *DT;
1319};

1321} // end namespace llvm

1323/// Optimize the uses in a given block This is basically the SSA renaming
1324/// algorithm, with one caveat: We are able to use a single stack for all
1325/// MemoryUses.  This is because the set of *possible* reaching MemoryDefs is
1326/// the same for every MemoryUse.  The *actual* clobbering MemoryDef is just
1327/// going to be some position in that stack of possible ones.
1328///
1329/// We track the stack positions that each MemoryLocation needs
1330/// to check, and last ended at.  This is because we only want to check the
1331/// things that changed since last time.  The same MemoryLocation should
1332/// get clobbered by the same store (getModRefInfo does not use invariantness or
1333/// things like this, and if they start, we can modify MemoryLocOrCall to
1334/// include relevant data)
1335void MemorySSA::OptimizeUses::optimizeUsesInBlock(
  const BasicBlock *BB, unsigned long &StackEpoch, unsigned long &PopEpoch,
  SmallVectorImpl<MemoryAccess *> &VersionStack,
  DenseMap<MemoryLocOrCall, MemlocStackInfo> &LocStackInfo) {

/// If no accesses, nothing to do.
MemorySSA::AccessList *Accesses = MSSA->getWritableBlockAccesses(BB);
if (Accesses == nullptr)
  return;

// Pop everything that doesn't dominate the current block off the stack,
// increment the PopEpoch to account for this.
while (true) {
  assert((static_cast <bool> (!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything"
) ? void (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1350, __extension__ __PRETTY_FUNCTION__
))
      !VersionStack.empty() &&(static_cast <bool> (!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything"
) ? void (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1350, __extension__ __PRETTY_FUNCTION__
))
      "Version stack should have liveOnEntry sentinel dominating everything")(static_cast <bool> (!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything"
) ? void (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1350, __extension__ __PRETTY_FUNCTION__
));
  BasicBlock *BackBlock = VersionStack.back()->getBlock();
  if (DT->dominates(BackBlock, BB))
    break;
  while (VersionStack.back()->getBlock() == BackBlock)
    VersionStack.pop_back();
  ++PopEpoch;
}

for (MemoryAccess &MA : *Accesses) {
  auto *MU = dyn_cast<MemoryUse>(&MA);
  if (!MU) {
    VersionStack.push_back(&MA);
    ++StackEpoch;
    continue;
  }

  if (MU->isOptimized())
    continue;

  if (isUseTriviallyOptimizableToLiveOnEntry(*AA, MU->getMemoryInst())) {
    MU->setDefiningAccess(MSSA->getLiveOnEntryDef(), true);
    continue;
  }

  MemoryLocOrCall UseMLOC(MU);
  auto &LocInfo = LocStackInfo[UseMLOC];
  // If the pop epoch changed, it means we've removed stuff from top of
  // stack due to changing blocks. We may have to reset the lower bound or
  // last kill info.
  if (LocInfo.PopEpoch != PopEpoch) {
    LocInfo.PopEpoch = PopEpoch;
    LocInfo.StackEpoch = StackEpoch;
    // If the lower bound was in something that no longer dominates us, we
    // have to reset it.
    // We can't simply track stack size, because the stack may have had
    // pushes/pops in the meantime.
    // XXX: This is non-optimal, but only is slower cases with heavily
    // branching dominator trees.  To get the optimal number of queries would
    // be to make lowerbound and lastkill a per-loc stack, and pop it until
    // the top of that stack dominates us.  This does not seem worth it ATM.
    // A much cheaper optimization would be to always explore the deepest
    // branch of the dominator tree first. This will guarantee this resets on
    // the smallest set of blocks.
    if (LocInfo.LowerBoundBlock && LocInfo.LowerBoundBlock != BB &&
        !DT->dominates(LocInfo.LowerBoundBlock, BB)) {
      // Reset the lower bound of things to check.
      // TODO: Some day we should be able to reset to last kill, rather than
      // 0.
      LocInfo.LowerBound = 0;
      LocInfo.LowerBoundBlock = VersionStack[0]->getBlock();
      LocInfo.LastKillValid = false;
    }
  } else if (LocInfo.StackEpoch != StackEpoch) {
    // If all that has changed is the StackEpoch, we only have to check the
    // new things on the stack, because we've checked everything before.  In
    // this case, the lower bound of things to check remains the same.
    LocInfo.PopEpoch = PopEpoch;
    LocInfo.StackEpoch = StackEpoch;
  }
  if (!LocInfo.LastKillValid) {
    LocInfo.LastKill = VersionStack.size() - 1;
    LocInfo.LastKillValid = true;
  }

  // At this point, we should have corrected last kill and LowerBound to be
  // in bounds.
  assert(LocInfo.LowerBound < VersionStack.size() &&(static_cast <bool> (LocInfo.LowerBound < VersionStack
.size() && "Lower bound out of range") ? void (0) : __assert_fail
 ("LocInfo.LowerBound < VersionStack.size() && \"Lower bound out of range\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1418, __extension__ __PRETTY_FUNCTION__
))
         "Lower bound out of range")(static_cast <bool> (LocInfo.LowerBound < VersionStack
.size() && "Lower bound out of range") ? void (0) : __assert_fail
 ("LocInfo.LowerBound < VersionStack.size() && \"Lower bound out of range\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1418, __extension__ __PRETTY_FUNCTION__
));
  assert(LocInfo.LastKill < VersionStack.size() &&(static_cast <bool> (LocInfo.LastKill < VersionStack
.size() && "Last kill info out of range") ? void (0) :
 __assert_fail ("LocInfo.LastKill < VersionStack.size() && \"Last kill info out of range\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1420, __extension__ __PRETTY_FUNCTION__
))
         "Last kill info out of range")(static_cast <bool> (LocInfo.LastKill < VersionStack
.size() && "Last kill info out of range") ? void (0) :
 __assert_fail ("LocInfo.LastKill < VersionStack.size() && \"Last kill info out of range\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1420, __extension__ __PRETTY_FUNCTION__
));
  // In any case, the new upper bound is the top of the stack.
  unsigned long UpperBound = VersionStack.size() - 1;

  if (UpperBound - LocInfo.LowerBound > MaxCheckLimit) {
    LLVM_DEBUG(dbgs() << "MemorySSA skipping optimization of " << *MU << " ("do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "MemorySSA skipping optimization of "
 << *MU << " (" << *(MU->getMemoryInst()
) << ")" << " because there are " << UpperBound
 - LocInfo.LowerBound << " stores to disambiguate\n"; }
 } while (false)
                      << *(MU->getMemoryInst()) << ")"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "MemorySSA skipping optimization of "
 << *MU << " (" << *(MU->getMemoryInst()
) << ")" << " because there are " << UpperBound
 - LocInfo.LowerBound << " stores to disambiguate\n"; }
 } while (false)
                      << " because there are "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "MemorySSA skipping optimization of "
 << *MU << " (" << *(MU->getMemoryInst()
) << ")" << " because there are " << UpperBound
 - LocInfo.LowerBound << " stores to disambiguate\n"; }
 } while (false)
                      << UpperBound - LocInfo.LowerBounddo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "MemorySSA skipping optimization of "
 << *MU << " (" << *(MU->getMemoryInst()
) << ")" << " because there are " << UpperBound
 - LocInfo.LowerBound << " stores to disambiguate\n"; }
 } while (false)
                      << " stores to disambiguate\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "MemorySSA skipping optimization of "
 << *MU << " (" << *(MU->getMemoryInst()
) << ")" << " because there are " << UpperBound
 - LocInfo.LowerBound << " stores to disambiguate\n"; }
 } while (false);
    // Because we did not walk, LastKill is no longer valid, as this may
    // have been a kill.
    LocInfo.LastKillValid = false;
    continue;
  }
  bool FoundClobberResult = false;
  unsigned UpwardWalkLimit = MaxCheckLimit;
  while (UpperBound > LocInfo.LowerBound) {
    if (isa<MemoryPhi>(VersionStack[UpperBound])) {
      // For phis, use the walker, see where we ended up, go there.
      // The invariant.group handling in MemorySSA is ad-hoc and doesn't
      // support updates, so don't use it to optimize uses.
      MemoryAccess *Result =
          Walker->getClobberingMemoryAccessWithoutInvariantGroup(
              MU, *AA, UpwardWalkLimit);
      // We are guaranteed to find it or something is wrong.
      while (VersionStack[UpperBound] != Result) {
        assert(UpperBound != 0)(static_cast <bool> (UpperBound != 0) ? void (0) : __assert_fail
 ("UpperBound != 0", "llvm/lib/Analysis/MemorySSA.cpp", 1447,
 __extension__ __PRETTY_FUNCTION__));
        --UpperBound;
      }
      FoundClobberResult = true;
      break;
    }

    MemoryDef *MD = cast<MemoryDef>(VersionStack[UpperBound]);
    if (instructionClobbersQuery(MD, MU, UseMLOC, *AA)) {
      FoundClobberResult = true;
      break;
    }
    --UpperBound;
  }

  // At the end of this loop, UpperBound is either a clobber, or lower bound
  // PHI walking may cause it to be < LowerBound, and in fact, < LastKill.
  if (FoundClobberResult || UpperBound < LocInfo.LastKill) {
    MU->setDefiningAccess(VersionStack[UpperBound], true);
    LocInfo.LastKill = UpperBound;
  } else {
    // Otherwise, we checked all the new ones, and now we know we can get to
    // LastKill.
    MU->setDefiningAccess(VersionStack[LocInfo.LastKill], true);
  }
  LocInfo.LowerBound = VersionStack.size() - 1;
  LocInfo.LowerBoundBlock = BB;
}
1475}

1477/// Optimize uses to point to their actual clobbering definitions.
1478void MemorySSA::OptimizeUses::optimizeUses() {
SmallVector<MemoryAccess *, 16> VersionStack;
DenseMap<MemoryLocOrCall, MemlocStackInfo> LocStackInfo;
VersionStack.push_back(MSSA->getLiveOnEntryDef());

unsigned long StackEpoch = 1;
unsigned long PopEpoch = 1;
// We perform a non-recursive top-down dominator tree walk.
for (const auto *DomNode : depth_first(DT->getRootNode()))
  optimizeUsesInBlock(DomNode->getBlock(), StackEpoch, PopEpoch, VersionStack,
                      LocStackInfo);
1489}

1491void MemorySSA::placePHINodes(
  const SmallPtrSetImpl<BasicBlock *> &DefiningBlocks) {
// Determine where our MemoryPhi's should go
ForwardIDFCalculator IDFs(*DT);
IDFs.setDefiningBlocks(DefiningBlocks);
SmallVector<BasicBlock *, 32> IDFBlocks;
IDFs.calculate(IDFBlocks);

// Now place MemoryPhi nodes.
for (auto &BB : IDFBlocks)
  createMemoryPhi(BB);
1502}

1504void MemorySSA::buildMemorySSA(BatchAAResults &BAA) {
// We create an access to represent "live on entry", for things like
// arguments or users of globals, where the memory they use is defined before
// the beginning of the function. We do not actually insert it into the IR.
// We do not define a live on exit for the immediate uses, and thus our
// semantics do *not* imply that something with no immediate uses can simply
// be removed.
BasicBlock &StartingPoint = F.getEntryBlock();
LiveOnEntryDef.reset(new MemoryDef(F.getContext(), nullptr, nullptr,
                                   &StartingPoint, NextID++));

// We maintain lists of memory accesses per-block, trading memory for time. We
// could just look up the memory access for every possible instruction in the
// stream.
SmallPtrSet<BasicBlock *, 32> DefiningBlocks;
// Go through each block, figure out where defs occur, and chain together all
// the accesses.
for (BasicBlock &B : F) {
  bool InsertIntoDef = false;
  AccessList *Accesses = nullptr;
  DefsList *Defs = nullptr;
  for (Instruction &I : B) {
    MemoryUseOrDef *MUD = createNewAccess(&I, &BAA);
    if (!MUD)
      continue;

    if (!Accesses)
      Accesses = getOrCreateAccessList(&B);
    Accesses->push_back(MUD);
    if (isa<MemoryDef>(MUD)) {
      InsertIntoDef = true;
      if (!Defs)
        Defs = getOrCreateDefsList(&B);
      Defs->push_back(*MUD);
    }
  }
  if (InsertIntoDef)
    DefiningBlocks.insert(&B);
}
placePHINodes(DefiningBlocks);

// Now do regular SSA renaming on the MemoryDef/MemoryUse. Visited will get
// filled in with all blocks.
SmallPtrSet<BasicBlock *, 16> Visited;
renamePass(DT->getRootNode(), LiveOnEntryDef.get(), Visited);

// Mark the uses in unreachable blocks as live on entry, so that they go
// somewhere.
for (auto &BB : F)
  if (!Visited.count(&BB))
    markUnreachableAsLiveOnEntry(&BB);
1555}

1557MemorySSAWalker *MemorySSA::getWalker() { return getWalkerImpl(); }

1559MemorySSA::CachingWalker *MemorySSA::getWalkerImpl() {
if (Walker)
  return Walker.get();

if (!WalkerBase)
  WalkerBase = std::make_unique<ClobberWalkerBase>(this, DT);

Walker = std::make_unique<CachingWalker>(this, WalkerBase.get());
return Walker.get();
1568}

1570MemorySSAWalker *MemorySSA::getSkipSelfWalker() {
if (SkipWalker)
  return SkipWalker.get();

if (!WalkerBase)
  WalkerBase = std::make_unique<ClobberWalkerBase>(this, DT);

SkipWalker = std::make_unique<SkipSelfWalker>(this, WalkerBase.get());
return SkipWalker.get();
}


1582// This is a helper function used by the creation routines. It places NewAccess
1583// into the access and defs lists for a given basic block, at the given
1584// insertion point.
1585void MemorySSA::insertIntoListsForBlock(MemoryAccess *NewAccess,
                                      const BasicBlock *BB,
                                      InsertionPlace Point) {
auto *Accesses = getOrCreateAccessList(BB);
if (Point == Beginning) {
  // If it's a phi node, it goes first, otherwise, it goes after any phi
  // nodes.
  if (isa<MemoryPhi>(NewAccess)) {
    Accesses->push_front(NewAccess);
    auto *Defs = getOrCreateDefsList(BB);
    Defs->push_front(*NewAccess);
  } else {
    auto AI = find_if_not(
        *Accesses, [](const MemoryAccess &MA) { return isa<MemoryPhi>(MA); });
    Accesses->insert(AI, NewAccess);
    if (!isa<MemoryUse>(NewAccess)) {
      auto *Defs = getOrCreateDefsList(BB);
      auto DI = find_if_not(
          *Defs, [](const MemoryAccess &MA) { return isa<MemoryPhi>(MA); });
      Defs->insert(DI, *NewAccess);
    }
  }
} else {
  Accesses->push_back(NewAccess);
  if (!isa<MemoryUse>(NewAccess)) {
    auto *Defs = getOrCreateDefsList(BB);
    Defs->push_back(*NewAccess);
  }
}
BlockNumberingValid.erase(BB);
1615}

1617void MemorySSA::insertIntoListsBefore(MemoryAccess *What, const BasicBlock *BB,
                                    AccessList::iterator InsertPt) {
auto *Accesses = getWritableBlockAccesses(BB);
bool WasEnd = InsertPt == Accesses->end();
Accesses->insert(AccessList::iterator(InsertPt), What);
if (!isa<MemoryUse>(What)) {
  auto *Defs = getOrCreateDefsList(BB);
  // If we got asked to insert at the end, we have an easy job, just shove it
  // at the end. If we got asked to insert before an existing def, we also get
  // an iterator. If we got asked to insert before a use, we have to hunt for
  // the next def.
  if (WasEnd) {
    Defs->push_back(*What);
  } else if (isa<MemoryDef>(InsertPt)) {
    Defs->insert(InsertPt->getDefsIterator(), *What);
  } else {
    while (InsertPt != Accesses->end() && !isa<MemoryDef>(InsertPt))
      ++InsertPt;
    // Either we found a def, or we are inserting at the end
    if (InsertPt == Accesses->end())
      Defs->push_back(*What);
    else
      Defs->insert(InsertPt->getDefsIterator(), *What);
  }
}
BlockNumberingValid.erase(BB);
1643}

1645void MemorySSA::prepareForMoveTo(MemoryAccess *What, BasicBlock *BB) {
// Keep it in the lookup tables, remove from the lists
removeFromLists(What, false);

// Note that moving should implicitly invalidate the optimized state of a
// MemoryUse (and Phis can't be optimized). However, it doesn't do so for a
// MemoryDef.
if (auto *MD = dyn_cast<MemoryDef>(What))
  MD->resetOptimized();
What->setBlock(BB);
1655}

1657// Move What before Where in the IR.  The end result is that What will belong to
1658// the right lists and have the right Block set, but will not otherwise be
1659// correct. It will not have the right defining access, and if it is a def,
1660// things below it will not properly be updated.
1661void MemorySSA::moveTo(MemoryUseOrDef *What, BasicBlock *BB,
                     AccessList::iterator Where) {
prepareForMoveTo(What, BB);
insertIntoListsBefore(What, BB, Where);
1665}

1667void MemorySSA::moveTo(MemoryAccess *What, BasicBlock *BB,
                     InsertionPlace Point) {
if (isa<MemoryPhi>(What)) {
  assert(Point == Beginning &&(static_cast <bool> (Point == Beginning && "Can only move a Phi at the beginning of the block"
) ? void (0) : __assert_fail ("Point == Beginning && \"Can only move a Phi at the beginning of the block\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1671, __extension__ __PRETTY_FUNCTION__
))
         "Can only move a Phi at the beginning of the block")(static_cast <bool> (Point == Beginning && "Can only move a Phi at the beginning of the block"
) ? void (0) : __assert_fail ("Point == Beginning && \"Can only move a Phi at the beginning of the block\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1671, __extension__ __PRETTY_FUNCTION__
));
  // Update lookup table entry
  ValueToMemoryAccess.erase(What->getBlock());
  bool Inserted = ValueToMemoryAccess.insert({BB, What}).second;
  (void)Inserted;
  assert(Inserted && "Cannot move a Phi to a block that already has one")(static_cast <bool> (Inserted && "Cannot move a Phi to a block that already has one"
) ? void (0) : __assert_fail ("Inserted && \"Cannot move a Phi to a block that already has one\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1676, __extension__ __PRETTY_FUNCTION__
));
}

prepareForMoveTo(What, BB);
insertIntoListsForBlock(What, BB, Point);
1681}

1683MemoryPhi *MemorySSA::createMemoryPhi(BasicBlock *BB) {
assert(!getMemoryAccess(BB) && "MemoryPhi already exists for this BB")(static_cast <bool> (!getMemoryAccess(BB) && "MemoryPhi already exists for this BB"
) ? void (0) : __assert_fail ("!getMemoryAccess(BB) && \"MemoryPhi already exists for this BB\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1684, __extension__ __PRETTY_FUNCTION__
));
MemoryPhi *Phi = new MemoryPhi(BB->getContext(), BB, NextID++);
// Phi's always are placed at the front of the block.
insertIntoListsForBlock(Phi, BB, Beginning);
ValueToMemoryAccess[BB] = Phi;
return Phi;
1690}

1692MemoryUseOrDef *MemorySSA::createDefinedAccess(Instruction *I,
                                             MemoryAccess *Definition,
                                             const MemoryUseOrDef *Template,
                                             bool CreationMustSucceed) {
assert(!isa<PHINode>(I) && "Cannot create a defined access for a PHI")(static_cast <bool> (!isa<PHINode>(I) && "Cannot create a defined access for a PHI"
) ? void (0) : __assert_fail ("!isa<PHINode>(I) && \"Cannot create a defined access for a PHI\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1696, __extension__ __PRETTY_FUNCTION__
));
MemoryUseOrDef *NewAccess = createNewAccess(I, AA, Template);
if (CreationMustSucceed)
  assert(NewAccess != nullptr && "Tried to create a memory access for a "(static_cast <bool> (NewAccess != nullptr && "Tried to create a memory access for a "
 "non-memory touching instruction") ? void (0) : __assert_fail
 ("NewAccess != nullptr && \"Tried to create a memory access for a \" \"non-memory touching instruction\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1700, __extension__ __PRETTY_FUNCTION__
))
                                 "non-memory touching instruction")(static_cast <bool> (NewAccess != nullptr && "Tried to create a memory access for a "
 "non-memory touching instruction") ? void (0) : __assert_fail
 ("NewAccess != nullptr && \"Tried to create a memory access for a \" \"non-memory touching instruction\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1700, __extension__ __PRETTY_FUNCTION__
));
if (NewAccess) {
  assert((!Definition || !isa<MemoryUse>(Definition)) &&(static_cast <bool> ((!Definition || !isa<MemoryUse>
(Definition)) && "A use cannot be a defining access")
 ? void (0) : __assert_fail ("(!Definition || !isa<MemoryUse>(Definition)) && \"A use cannot be a defining access\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1703, __extension__ __PRETTY_FUNCTION__
))
         "A use cannot be a defining access")(static_cast <bool> ((!Definition || !isa<MemoryUse>
(Definition)) && "A use cannot be a defining access")
 ? void (0) : __assert_fail ("(!Definition || !isa<MemoryUse>(Definition)) && \"A use cannot be a defining access\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1703, __extension__ __PRETTY_FUNCTION__
));
  NewAccess->setDefiningAccess(Definition);
}
return NewAccess;
1707}

1709// Return true if the instruction has ordering constraints.
1710// Note specifically that this only considers stores and loads
1711// because others are still considered ModRef by getModRefInfo.
1712static inline bool isOrdered(const Instruction *I) {
if (auto *SI = dyn_cast<StoreInst>(I)) {
  if (!SI->isUnordered())
    return true;
} else if (auto *LI = dyn_cast<LoadInst>(I)) {
  if (!LI->isUnordered())
    return true;
}
return false;
1721}

1723/// Helper function to create new memory accesses
1724template <typename AliasAnalysisType>
1725MemoryUseOrDef *MemorySSA::createNewAccess(Instruction *I,
                                         AliasAnalysisType *AAP,
                                         const MemoryUseOrDef *Template) {
// The assume intrinsic has a control dependency which we model by claiming
// that it writes arbitrarily. Debuginfo intrinsics may be considered
// clobbers when we have a nonstandard AA pipeline. Ignore these fake memory
// dependencies here.
// FIXME: Replace this special casing with a more accurate modelling of
// assume's control dependency.
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
  switch (II->getIntrinsicID()) {
  default:
    break;
  case Intrinsic::assume:
  case Intrinsic::experimental_noalias_scope_decl:
  case Intrinsic::pseudoprobe:
    return nullptr;
  }
}

// Using a nonstandard AA pipelines might leave us with unexpected modref
// results for I, so add a check to not model instructions that may not read
// from or write to memory. This is necessary for correctness.
if (!I->mayReadFromMemory() && !I->mayWriteToMemory())
  return nullptr;

bool Def, Use;
if (Template) {
  Def = isa<MemoryDef>(Template);
  Use = isa<MemoryUse>(Template);
1755#if !defined(NDEBUG)
  ModRefInfo ModRef = AAP->getModRefInfo(I, std::nullopt);
  bool DefCheck, UseCheck;
  DefCheck = isModSet(ModRef) || isOrdered(I);
  UseCheck = isRefSet(ModRef);
  // Memory accesses should only be reduced and can not be increased since AA
  // just might return better results as a result of some transformations.
  assert((Def == DefCheck || !DefCheck) &&(static_cast <bool> ((Def == DefCheck || !DefCheck) &&
 "Memory accesses should only be reduced") ? void (0) : __assert_fail
 ("(Def == DefCheck || !DefCheck) && \"Memory accesses should only be reduced\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1763, __extension__ __PRETTY_FUNCTION__
))
         "Memory accesses should only be reduced")(static_cast <bool> ((Def == DefCheck || !DefCheck) &&
 "Memory accesses should only be reduced") ? void (0) : __assert_fail
 ("(Def == DefCheck || !DefCheck) && \"Memory accesses should only be reduced\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1763, __extension__ __PRETTY_FUNCTION__
));
  if (!Def && Use != UseCheck) {
    // New Access should not have more power than template access
    assert(!UseCheck && "Invalid template")(static_cast <bool> (!UseCheck && "Invalid template"
) ? void (0) : __assert_fail ("!UseCheck && \"Invalid template\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1766, __extension__ __PRETTY_FUNCTION__
));
  }
1768#endif
} else {
  // Find out what affect this instruction has on memory.
  ModRefInfo ModRef = AAP->getModRefInfo(I, std::nullopt);
  // The isOrdered check is used to ensure that volatiles end up as defs
  // (atomics end up as ModRef right now anyway).  Until we separate the
  // ordering chain from the memory chain, this enables people to see at least
  // some relative ordering to volatiles.  Note that getClobberingMemoryAccess
  // will still give an answer that bypasses other volatile loads.  TODO:
  // Separate memory aliasing and ordering into two different chains so that
  // we can precisely represent both "what memory will this read/write/is
  // clobbered by" and "what instructions can I move this past".
  Def = isModSet(ModRef) || isOrdered(I);
  Use = isRefSet(ModRef);
}

// It's possible for an instruction to not modify memory at all. During
// construction, we ignore them.
if (!Def && !Use)
  return nullptr;

MemoryUseOrDef *MUD;
if (Def)
  MUD = new MemoryDef(I->getContext(), nullptr, I, I->getParent(), NextID++);
else
  MUD = new MemoryUse(I->getContext(), nullptr, I, I->getParent());
ValueToMemoryAccess[I] = MUD;
return MUD;
1796}

1798/// Properly remove \p MA from all of MemorySSA's lookup tables.
1799void MemorySSA::removeFromLookups(MemoryAccess *MA) {
assert(MA->use_empty() &&(static_cast <bool> (MA->use_empty() && "Trying to remove memory access that still has uses"
) ? void (0) : __assert_fail ("MA->use_empty() && \"Trying to remove memory access that still has uses\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1801, __extension__ __PRETTY_FUNCTION__
))
       "Trying to remove memory access that still has uses")(static_cast <bool> (MA->use_empty() && "Trying to remove memory access that still has uses"
) ? void (0) : __assert_fail ("MA->use_empty() && \"Trying to remove memory access that still has uses\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1801, __extension__ __PRETTY_FUNCTION__
));
BlockNumbering.erase(MA);
if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
  MUD->setDefiningAccess(nullptr);
// Invalidate our walker's cache if necessary
if (!isa<MemoryUse>(MA))
  getWalker()->invalidateInfo(MA);

Value *MemoryInst;
if (const auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
  MemoryInst = MUD->getMemoryInst();
else
  MemoryInst = MA->getBlock();

auto VMA = ValueToMemoryAccess.find(MemoryInst);
if (VMA->second == MA)
  ValueToMemoryAccess.erase(VMA);
1818}

1820/// Properly remove \p MA from all of MemorySSA's lists.
1821///
1822/// Because of the way the intrusive list and use lists work, it is important to
1823/// do removal in the right order.
1824/// ShouldDelete defaults to true, and will cause the memory access to also be
1825/// deleted, not just removed.
1826void MemorySSA::removeFromLists(MemoryAccess *MA, bool ShouldDelete) {
BasicBlock *BB = MA->getBlock();
// The access list owns the reference, so we erase it from the non-owning list
// first.
if (!isa<MemoryUse>(MA)) {
  auto DefsIt = PerBlockDefs.find(BB);
  std::unique_ptr<DefsList> &Defs = DefsIt->second;
  Defs->remove(*MA);
  if (Defs->empty())
    PerBlockDefs.erase(DefsIt);
}

// The erase call here will delete it. If we don't want it deleted, we call
// remove instead.
auto AccessIt = PerBlockAccesses.find(BB);
std::unique_ptr<AccessList> &Accesses = AccessIt->second;
if (ShouldDelete)
  Accesses->erase(MA);
else
  Accesses->remove(MA);

if (Accesses->empty()) {
  PerBlockAccesses.erase(AccessIt);
  BlockNumberingValid.erase(BB);
}
1851}

1853void MemorySSA::print(raw_ostream &OS) const {
MemorySSAAnnotatedWriter Writer(this);
F.print(OS, &Writer);
1856}

1858#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1859LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void MemorySSA::dump() const { print(dbgs()); }
1860#endif

1862void MemorySSA::verifyMemorySSA(VerificationLevel VL) const {
1863#if !defined(NDEBUG) && defined(EXPENSIVE_CHECKS)
VL = VerificationLevel::Full;
1865#endif

1867#ifndef NDEBUG
verifyOrderingDominationAndDefUses(F, VL);
4
←
Calling 'MemorySSA::verifyOrderingDominationAndDefUses'→
verifyDominationNumbers(F);
if (VL == VerificationLevel::Full)
  verifyPrevDefInPhis(F);
1872#endif
// Previously, the verification used to also verify that the clobberingAccess
// cached by MemorySSA is the same as the clobberingAccess found at a later
// query to AA. This does not hold true in general due to the current fragility
// of BasicAA which has arbitrary caps on the things it analyzes before giving
// up. As a result, transformations that are correct, will lead to BasicAA
// returning different Alias answers before and after that transformation.
// Invalidating MemorySSA is not an option, as the results in BasicAA can be so
// random, in the worst case we'd need to rebuild MemorySSA from scratch after
// every transformation, which defeats the purpose of using it. For such an
// example, see test4 added in D51960.
1883}

1885void MemorySSA::verifyPrevDefInPhis(Function &F) const {
for (const BasicBlock &BB : F) {
  if (MemoryPhi *Phi = getMemoryAccess(&BB)) {
    for (unsigned I = 0, E = Phi->getNumIncomingValues(); I != E; ++I) {
      auto *Pred = Phi->getIncomingBlock(I);
      auto *IncAcc = Phi->getIncomingValue(I);
      // If Pred has no unreachable predecessors, get last def looking at
      // IDoms. If, while walkings IDoms, any of these has an unreachable
      // predecessor, then the incoming def can be any access.
      if (auto *DTNode = DT->getNode(Pred)) {
        while (DTNode) {
          if (auto *DefList = getBlockDefs(DTNode->getBlock())) {
            auto *LastAcc = &*(--DefList->end());
            assert(LastAcc == IncAcc &&(static_cast <bool> (LastAcc == IncAcc && "Incorrect incoming access into phi."
) ? void (0) : __assert_fail ("LastAcc == IncAcc && \"Incorrect incoming access into phi.\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1899, __extension__ __PRETTY_FUNCTION__
))
                   "Incorrect incoming access into phi.")(static_cast <bool> (LastAcc == IncAcc && "Incorrect incoming access into phi."
) ? void (0) : __assert_fail ("LastAcc == IncAcc && \"Incorrect incoming access into phi.\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1899, __extension__ __PRETTY_FUNCTION__
));
            (void)IncAcc;
            (void)LastAcc;
            break;
          }
          DTNode = DTNode->getIDom();
        }
      } else {
        // If Pred has unreachable predecessors, but has at least a Def, the
        // incoming access can be the last Def in Pred, or it could have been
        // optimized to LoE. After an update, though, the LoE may have been
        // replaced by another access, so IncAcc may be any access.
        // If Pred has unreachable predecessors and no Defs, incoming access
        // should be LoE; However, after an update, it may be any access.
      }
    }
  }
}
1917}

1919/// Verify that all of the blocks we believe to have valid domination numbers
1920/// actually have valid domination numbers.
1921void MemorySSA::verifyDominationNumbers(const Function &F) const {
if (BlockNumberingValid.empty())
  return;

SmallPtrSet<const BasicBlock *, 16> ValidBlocks = BlockNumberingValid;
for (const BasicBlock &BB : F) {
  if (!ValidBlocks.count(&BB))
    continue;

  ValidBlocks.erase(&BB);

  const AccessList *Accesses = getBlockAccesses(&BB);
  // It's correct to say an empty block has valid numbering.
  if (!Accesses)
    continue;

  // Block numbering starts at 1.
  unsigned long LastNumber = 0;
  for (const MemoryAccess &MA : *Accesses) {
    auto ThisNumberIter = BlockNumbering.find(&MA);
    assert(ThisNumberIter != BlockNumbering.end() &&(static_cast <bool> (ThisNumberIter != BlockNumbering.end
() && "MemoryAccess has no domination number in a valid block!"
) ? void (0) : __assert_fail ("ThisNumberIter != BlockNumbering.end() && \"MemoryAccess has no domination number in a valid block!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1942, __extension__ __PRETTY_FUNCTION__
))
           "MemoryAccess has no domination number in a valid block!")(static_cast <bool> (ThisNumberIter != BlockNumbering.end
() && "MemoryAccess has no domination number in a valid block!"
) ? void (0) : __assert_fail ("ThisNumberIter != BlockNumbering.end() && \"MemoryAccess has no domination number in a valid block!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1942, __extension__ __PRETTY_FUNCTION__
));

    unsigned long ThisNumber = ThisNumberIter->second;
    assert(ThisNumber > LastNumber &&(static_cast <bool> (ThisNumber > LastNumber &&
 "Domination numbers should be strictly increasing!") ? void (
0) : __assert_fail ("ThisNumber > LastNumber && \"Domination numbers should be strictly increasing!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1946, __extension__ __PRETTY_FUNCTION__
))
           "Domination numbers should be strictly increasing!")(static_cast <bool> (ThisNumber > LastNumber &&
 "Domination numbers should be strictly increasing!") ? void (
0) : __assert_fail ("ThisNumber > LastNumber && \"Domination numbers should be strictly increasing!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1946, __extension__ __PRETTY_FUNCTION__
));
    (void)LastNumber;
    LastNumber = ThisNumber;
  }
}

assert(ValidBlocks.empty() &&(static_cast <bool> (ValidBlocks.empty() && "All valid BasicBlocks should exist in F -- dangling pointers?"
) ? void (0) : __assert_fail ("ValidBlocks.empty() && \"All valid BasicBlocks should exist in F -- dangling pointers?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1953, __extension__ __PRETTY_FUNCTION__
))
       "All valid BasicBlocks should exist in F -- dangling pointers?")(static_cast <bool> (ValidBlocks.empty() && "All valid BasicBlocks should exist in F -- dangling pointers?"
) ? void (0) : __assert_fail ("ValidBlocks.empty() && \"All valid BasicBlocks should exist in F -- dangling pointers?\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1953, __extension__ __PRETTY_FUNCTION__
));
1954}

1956/// Verify ordering: the order and existence of MemoryAccesses matches the
1957/// order and existence of memory affecting instructions.
1958/// Verify domination: each definition dominates all of its uses.
1959/// Verify def-uses: the immediate use information - walk all the memory
1960/// accesses and verifying that, for each use, it appears in the appropriate
1961/// def's use list
1962void MemorySSA::verifyOrderingDominationAndDefUses(Function &F,
                                                 VerificationLevel VL) const {
// Walk all the blocks, comparing what the lookups think and what the access
// lists think, as well as the order in the blocks vs the order in the access
// lists.
SmallVector<MemoryAccess *, 32> ActualAccesses;
SmallVector<MemoryAccess *, 32> ActualDefs;
for (BasicBlock &B : F) {
  const AccessList *AL = getBlockAccesses(&B);
5
←
Calling 'MemorySSA::getBlockAccesses'→
13
←
Returning from 'MemorySSA::getBlockAccesses'→
14
←
'AL' initialized here→
  const auto *DL = getBlockDefs(&B);
15
←
Calling 'MemorySSA::getBlockDefs'→
21
←
Returning from 'MemorySSA::getBlockDefs'→
  MemoryPhi *Phi = getMemoryAccess(&B);
22
←
Calling 'MemorySSA::getMemoryAccess'→
26
←
Returning from 'MemorySSA::getMemoryAccess'→
  if (Phi26.1
'Phi' is null
1
'Phi' is null
) {
27
←
Taking false branch→
    // Verify ordering.
    ActualAccesses.push_back(Phi);
    ActualDefs.push_back(Phi);
    // Verify domination
    for (const Use &U : Phi->uses()) {
      assert(dominates(Phi, U) && "Memory PHI does not dominate it's uses")(static_cast <bool> (dominates(Phi, U) && "Memory PHI does not dominate it's uses"
) ? void (0) : __assert_fail ("dominates(Phi, U) && \"Memory PHI does not dominate it's uses\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1979, __extension__ __PRETTY_FUNCTION__
));
      (void)U;
    }
    // Verify def-uses for full verify.
    if (VL == VerificationLevel::Full) {
      assert(Phi->getNumOperands() == static_cast<unsigned>(std::distance((static_cast <bool> (Phi->getNumOperands() == static_cast
<unsigned>(std::distance( pred_begin(&B), pred_end(
&B))) && "Incomplete MemoryPhi Node") ? void (0) :
 __assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1986, __extension__ __PRETTY_FUNCTION__
))
                                          pred_begin(&B), pred_end(&B))) &&(static_cast <bool> (Phi->getNumOperands() == static_cast
<unsigned>(std::distance( pred_begin(&B), pred_end(
&B))) && "Incomplete MemoryPhi Node") ? void (0) :
 __assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1986, __extension__ __PRETTY_FUNCTION__
))
             "Incomplete MemoryPhi Node")(static_cast <bool> (Phi->getNumOperands() == static_cast
<unsigned>(std::distance( pred_begin(&B), pred_end(
&B))) && "Incomplete MemoryPhi Node") ? void (0) :
 __assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1986, __extension__ __PRETTY_FUNCTION__
));
      for (unsigned I = 0, E = Phi->getNumIncomingValues(); I != E; ++I) {
        verifyUseInDefs(Phi->getIncomingValue(I), Phi);
        assert(is_contained(predecessors(&B), Phi->getIncomingBlock(I)) &&(static_cast <bool> (is_contained(predecessors(&B),
 Phi->getIncomingBlock(I)) && "Incoming phi block not a block predecessor"
) ? void (0) : __assert_fail ("is_contained(predecessors(&B), Phi->getIncomingBlock(I)) && \"Incoming phi block not a block predecessor\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1990, __extension__ __PRETTY_FUNCTION__
))
               "Incoming phi block not a block predecessor")(static_cast <bool> (is_contained(predecessors(&B),
 Phi->getIncomingBlock(I)) && "Incoming phi block not a block predecessor"
) ? void (0) : __assert_fail ("is_contained(predecessors(&B), Phi->getIncomingBlock(I)) && \"Incoming phi block not a block predecessor\""
, "llvm/lib/Analysis/MemorySSA.cpp", 1990, __extension__ __PRETTY_FUNCTION__
));
      }
    }
  }

  for (Instruction &I : B) {
    MemoryUseOrDef *MA = getMemoryAccess(&I);
    assert((!MA || (AL && (isa<MemoryUse>(MA) || DL))) &&(static_cast <bool> ((!MA || (AL && (isa<MemoryUse
>(MA) || DL))) && "We have memory affecting instructions "
 "in this block but they are not in the " "access list or defs list"
) ? void (0) : __assert_fail ("(!MA || (AL && (isa<MemoryUse>(MA) || DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2000, __extension__ __PRETTY_FUNCTION__
))
           "We have memory affecting instructions "(static_cast <bool> ((!MA || (AL && (isa<MemoryUse
>(MA) || DL))) && "We have memory affecting instructions "
 "in this block but they are not in the " "access list or defs list"
) ? void (0) : __assert_fail ("(!MA || (AL && (isa<MemoryUse>(MA) || DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2000, __extension__ __PRETTY_FUNCTION__
))
           "in this block but they are not in the "(static_cast <bool> ((!MA || (AL && (isa<MemoryUse
>(MA) || DL))) && "We have memory affecting instructions "
 "in this block but they are not in the " "access list or defs list"
) ? void (0) : __assert_fail ("(!MA || (AL && (isa<MemoryUse>(MA) || DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2000, __extension__ __PRETTY_FUNCTION__
))
           "access list or defs list")(static_cast <bool> ((!MA || (AL && (isa<MemoryUse
>(MA) || DL))) && "We have memory affecting instructions "
 "in this block but they are not in the " "access list or defs list"
) ? void (0) : __assert_fail ("(!MA || (AL && (isa<MemoryUse>(MA) || DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2000, __extension__ __PRETTY_FUNCTION__
));
    if (MA) {
      // Verify ordering.
      ActualAccesses.push_back(MA);
      if (MemoryAccess *MD = dyn_cast<MemoryDef>(MA)) {
        // Verify ordering.
        ActualDefs.push_back(MA);
        // Verify domination.
        for (const Use &U : MD->uses()) {
          assert(dominates(MD, U) &&(static_cast <bool> (dominates(MD, U) && "Memory Def does not dominate it's uses"
) ? void (0) : __assert_fail ("dominates(MD, U) && \"Memory Def does not dominate it's uses\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2010, __extension__ __PRETTY_FUNCTION__
))
                 "Memory Def does not dominate it's uses")(static_cast <bool> (dominates(MD, U) && "Memory Def does not dominate it's uses"
) ? void (0) : __assert_fail ("dominates(MD, U) && \"Memory Def does not dominate it's uses\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2010, __extension__ __PRETTY_FUNCTION__
));
          (void)U;
        }
      }
      // Verify def-uses for full verify.
      if (VL == VerificationLevel::Full)
        verifyUseInDefs(MA->getDefiningAccess(), MA);
    }
  }
  // Either we hit the assert, really have no accesses, or we have both
  // accesses and an access list. Same with defs.
  if (!AL && !DL)
28
←
Assuming 'AL' is null→
29
←
Assuming 'DL' is non-null→
    continue;
  // Verify ordering.
  assert(AL->size() == ActualAccesses.size() &&(static_cast <bool> (AL->size() == ActualAccesses.size
() && "We don't have the same number of accesses in the block as on the "
 "access list") ? void (0) : __assert_fail ("AL->size() == ActualAccesses.size() && \"We don't have the same number of accesses in the block as on the \" \"access list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2026, __extension__ __PRETTY_FUNCTION__
))
30
←
Taking false branch→
31
←
Called C++ object pointer is null
         "We don't have the same number of accesses in the block as on the "(static_cast <bool> (AL->size() == ActualAccesses.size
() && "We don't have the same number of accesses in the block as on the "
 "access list") ? void (0) : __assert_fail ("AL->size() == ActualAccesses.size() && \"We don't have the same number of accesses in the block as on the \" \"access list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2026, __extension__ __PRETTY_FUNCTION__
))
         "access list")(static_cast <bool> (AL->size() == ActualAccesses.size
() && "We don't have the same number of accesses in the block as on the "
 "access list") ? void (0) : __assert_fail ("AL->size() == ActualAccesses.size() && \"We don't have the same number of accesses in the block as on the \" \"access list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2026, __extension__ __PRETTY_FUNCTION__
));
  assert((DL || ActualDefs.size() == 0) &&(static_cast <bool> ((DL || ActualDefs.size() == 0) &&
 "Either we should have a defs list, or we should have no defs"
) ? void (0) : __assert_fail ("(DL || ActualDefs.size() == 0) && \"Either we should have a defs list, or we should have no defs\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2028, __extension__ __PRETTY_FUNCTION__
))
         "Either we should have a defs list, or we should have no defs")(static_cast <bool> ((DL || ActualDefs.size() == 0) &&
 "Either we should have a defs list, or we should have no defs"
) ? void (0) : __assert_fail ("(DL || ActualDefs.size() == 0) && \"Either we should have a defs list, or we should have no defs\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2028, __extension__ __PRETTY_FUNCTION__
));
  assert((!DL || DL->size() == ActualDefs.size()) &&(static_cast <bool> ((!DL || DL->size() == ActualDefs
.size()) && "We don't have the same number of defs in the block as on the "
 "def list") ? void (0) : __assert_fail ("(!DL || DL->size() == ActualDefs.size()) && \"We don't have the same number of defs in the block as on the \" \"def list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2031, __extension__ __PRETTY_FUNCTION__
))
         "We don't have the same number of defs in the block as on the "(static_cast <bool> ((!DL || DL->size() == ActualDefs
.size()) && "We don't have the same number of defs in the block as on the "
 "def list") ? void (0) : __assert_fail ("(!DL || DL->size() == ActualDefs.size()) && \"We don't have the same number of defs in the block as on the \" \"def list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2031, __extension__ __PRETTY_FUNCTION__
))
         "def list")(static_cast <bool> ((!DL || DL->size() == ActualDefs
.size()) && "We don't have the same number of defs in the block as on the "
 "def list") ? void (0) : __assert_fail ("(!DL || DL->size() == ActualDefs.size()) && \"We don't have the same number of defs in the block as on the \" \"def list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2031, __extension__ __PRETTY_FUNCTION__
));
  auto ALI = AL->begin();
  auto AAI = ActualAccesses.begin();
  while (ALI != AL->end() && AAI != ActualAccesses.end()) {
    assert(&*ALI == *AAI && "Not the same accesses in the same order")(static_cast <bool> (&*ALI == *AAI && "Not the same accesses in the same order"
) ? void (0) : __assert_fail ("&*ALI == *AAI && \"Not the same accesses in the same order\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2035, __extension__ __PRETTY_FUNCTION__
));
    ++ALI;
    ++AAI;
  }
  ActualAccesses.clear();
  if (DL) {
    auto DLI = DL->begin();
    auto ADI = ActualDefs.begin();
    while (DLI != DL->end() && ADI != ActualDefs.end()) {
      assert(&*DLI == *ADI && "Not the same defs in the same order")(static_cast <bool> (&*DLI == *ADI && "Not the same defs in the same order"
) ? void (0) : __assert_fail ("&*DLI == *ADI && \"Not the same defs in the same order\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2044, __extension__ __PRETTY_FUNCTION__
));
      ++DLI;
      ++ADI;
    }
  }
  ActualDefs.clear();
}
2051}

2053/// Verify the def-use lists in MemorySSA, by verifying that \p Use
2054/// appears in the use list of \p Def.
2055void MemorySSA::verifyUseInDefs(MemoryAccess *Def, MemoryAccess *Use) const {
// The live on entry use may cause us to get a NULL def here
if (!Def)
  assert(isLiveOnEntryDef(Use) &&(static_cast <bool> (isLiveOnEntryDef(Use) && "Null def but use not point to live on entry def"
) ? void (0) : __assert_fail ("isLiveOnEntryDef(Use) && \"Null def but use not point to live on entry def\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2059, __extension__ __PRETTY_FUNCTION__
))
         "Null def but use not point to live on entry def")(static_cast <bool> (isLiveOnEntryDef(Use) && "Null def but use not point to live on entry def"
) ? void (0) : __assert_fail ("isLiveOnEntryDef(Use) && \"Null def but use not point to live on entry def\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2059, __extension__ __PRETTY_FUNCTION__
));
else
  assert(is_contained(Def->users(), Use) &&(static_cast <bool> (is_contained(Def->users(), Use)
 && "Did not find use in def's use list") ? void (0) :
 __assert_fail ("is_contained(Def->users(), Use) && \"Did not find use in def's use list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2062, __extension__ __PRETTY_FUNCTION__
))
         "Did not find use in def's use list")(static_cast <bool> (is_contained(Def->users(), Use)
 && "Did not find use in def's use list") ? void (0) :
 __assert_fail ("is_contained(Def->users(), Use) && \"Did not find use in def's use list\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2062, __extension__ __PRETTY_FUNCTION__
));
2063}

2065/// Perform a local numbering on blocks so that instruction ordering can be
2066/// determined in constant time.
2067/// TODO: We currently just number in order.  If we numbered by N, we could
2068/// allow at least N-1 sequences of insertBefore or insertAfter (and at least
2069/// log2(N) sequences of mixed before and after) without needing to invalidate
2070/// the numbering.
2071void MemorySSA::renumberBlock(const BasicBlock *B) const {
// The pre-increment ensures the numbers really start at 1.
unsigned long CurrentNumber = 0;
const AccessList *AL = getBlockAccesses(B);
assert(AL != nullptr && "Asking to renumber an empty block")(static_cast <bool> (AL != nullptr && "Asking to renumber an empty block"
) ? void (0) : __assert_fail ("AL != nullptr && \"Asking to renumber an empty block\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2075, __extension__ __PRETTY_FUNCTION__
));
for (const auto &I : *AL)
  BlockNumbering[&I] = ++CurrentNumber;
BlockNumberingValid.insert(B);
2079}

2081/// Determine, for two memory accesses in the same block,
2082/// whether \p Dominator dominates \p Dominatee.
2083/// \returns True if \p Dominator dominates \p Dominatee.
2084bool MemorySSA::locallyDominates(const MemoryAccess *Dominator,
                               const MemoryAccess *Dominatee) const {
const BasicBlock *DominatorBlock = Dominator->getBlock();

assert((DominatorBlock == Dominatee->getBlock()) &&(static_cast <bool> ((DominatorBlock == Dominatee->getBlock
()) && "Asking for local domination when accesses are in different blocks!"
) ? void (0) : __assert_fail ("(DominatorBlock == Dominatee->getBlock()) && \"Asking for local domination when accesses are in different blocks!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2089, __extension__ __PRETTY_FUNCTION__
))
       "Asking for local domination when accesses are in different blocks!")(static_cast <bool> ((DominatorBlock == Dominatee->getBlock
()) && "Asking for local domination when accesses are in different blocks!"
) ? void (0) : __assert_fail ("(DominatorBlock == Dominatee->getBlock()) && \"Asking for local domination when accesses are in different blocks!\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2089, __extension__ __PRETTY_FUNCTION__
));
// A node dominates itself.
if (Dominatee == Dominator)
  return true;

// When Dominatee is defined on function entry, it is not dominated by another
// memory access.
if (isLiveOnEntryDef(Dominatee))
  return false;

// When Dominator is defined on function entry, it dominates the other memory
// access.
if (isLiveOnEntryDef(Dominator))
  return true;

if (!BlockNumberingValid.count(DominatorBlock))
  renumberBlock(DominatorBlock);

unsigned long DominatorNum = BlockNumbering.lookup(Dominator);
// All numbers start with 1
assert(DominatorNum != 0 && "Block was not numbered properly")(static_cast <bool> (DominatorNum != 0 && "Block was not numbered properly"
) ? void (0) : __assert_fail ("DominatorNum != 0 && \"Block was not numbered properly\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2109, __extension__ __PRETTY_FUNCTION__
));
unsigned long DominateeNum = BlockNumbering.lookup(Dominatee);
assert(DominateeNum != 0 && "Block was not numbered properly")(static_cast <bool> (DominateeNum != 0 && "Block was not numbered properly"
) ? void (0) : __assert_fail ("DominateeNum != 0 && \"Block was not numbered properly\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2111, __extension__ __PRETTY_FUNCTION__
));
return DominatorNum < DominateeNum;
2113}

2115bool MemorySSA::dominates(const MemoryAccess *Dominator,
                        const MemoryAccess *Dominatee) const {
if (Dominator == Dominatee)
  return true;

if (isLiveOnEntryDef(Dominatee))
  return false;

if (Dominator->getBlock() != Dominatee->getBlock())
  return DT->dominates(Dominator->getBlock(), Dominatee->getBlock());
return locallyDominates(Dominator, Dominatee);
2126}

2128bool MemorySSA::dominates(const MemoryAccess *Dominator,
                        const Use &Dominatee) const {
if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Dominatee.getUser())) {
  BasicBlock *UseBB = MP->getIncomingBlock(Dominatee);
  // The def must dominate the incoming block of the phi.
  if (UseBB != Dominator->getBlock())
    return DT->dominates(Dominator->getBlock(), UseBB);
  // If the UseBB and the DefBB are the same, compare locally.
  return locallyDominates(Dominator, cast<MemoryAccess>(Dominatee));
}
// If it's not a PHI node use, the normal dominates can already handle it.
return dominates(Dominator, cast<MemoryAccess>(Dominatee.getUser()));
2140}

2142void MemorySSA::ensureOptimizedUses() {
if (IsOptimized)
  return;

BatchAAResults BatchAA(*AA);
ClobberWalkerBase WalkerBase(this, DT);
CachingWalker WalkerLocal(this, &WalkerBase);
OptimizeUses(this, &WalkerLocal, &BatchAA, DT).optimizeUses();
IsOptimized = true;
2151}

2153void MemoryAccess::print(raw_ostream &OS) const {
switch (getValueID()) {
case MemoryPhiVal: return static_cast<const MemoryPhi *>(this)->print(OS);
case MemoryDefVal: return static_cast<const MemoryDef *>(this)->print(OS);
case MemoryUseVal: return static_cast<const MemoryUse *>(this)->print(OS);
}
llvm_unreachable("invalid value id")::llvm::llvm_unreachable_internal("invalid value id", "llvm/lib/Analysis/MemorySSA.cpp"
, 2159);
2160}

2162void MemoryDef::print(raw_ostream &OS) const {
MemoryAccess *UO = getDefiningAccess();

auto printID = [&OS](MemoryAccess *A) {
  if (A && A->getID())
    OS << A->getID();
  else
    OS << LiveOnEntryStr;
};

OS << getID() << " = MemoryDef(";
printID(UO);
OS << ")";

if (isOptimized()) {
  OS << "->";
  printID(getOptimized());
}
2180}

2182void MemoryPhi::print(raw_ostream &OS) const {
ListSeparator LS(",");
OS << getID() << " = MemoryPhi(";
for (const auto &Op : operands()) {
  BasicBlock *BB = getIncomingBlock(Op);
  MemoryAccess *MA = cast<MemoryAccess>(Op);

  OS << LS << '{';
  if (BB->hasName())
    OS << BB->getName();
  else
    BB->printAsOperand(OS, false);
  OS << ',';
  if (unsigned ID = MA->getID())
    OS << ID;
  else
    OS << LiveOnEntryStr;
  OS << '}';
}
OS << ')';
2202}

2204void MemoryUse::print(raw_ostream &OS) const {
MemoryAccess *UO = getDefiningAccess();
OS << "MemoryUse(";
if (UO && UO->getID())
  OS << UO->getID();
else
  OS << LiveOnEntryStr;
OS << ')';
2212}

2214void MemoryAccess::dump() const {
2215// Cannot completely remove virtual function even in release mode.
2216#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
print(dbgs());
dbgs() << "\n";
2219#endif
2220}

2222char MemorySSAPrinterLegacyPass::ID = 0;

2224MemorySSAPrinterLegacyPass::MemorySSAPrinterLegacyPass() : FunctionPass(ID) {
initializeMemorySSAPrinterLegacyPassPass(*PassRegistry::getPassRegistry());
2226}

2228void MemorySSAPrinterLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<MemorySSAWrapperPass>();
2231}

2233class DOTFuncMSSAInfo {
2234private:
const Function &F;
MemorySSAAnnotatedWriter MSSAWriter;

2238public:
DOTFuncMSSAInfo(const Function &F, MemorySSA &MSSA)
    : F(F), MSSAWriter(&MSSA) {}

const Function *getFunction() { return &F; }
MemorySSAAnnotatedWriter &getWriter() { return MSSAWriter; }
2244};

2246namespace llvm {

2248template <>
2249struct GraphTraits<DOTFuncMSSAInfo *> : public GraphTraits<const BasicBlock *> {
static NodeRef getEntryNode(DOTFuncMSSAInfo *CFGInfo) {
  return &(CFGInfo->getFunction()->getEntryBlock());
}

// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
using nodes_iterator = pointer_iterator<Function::const_iterator>;

static nodes_iterator nodes_begin(DOTFuncMSSAInfo *CFGInfo) {
  return nodes_iterator(CFGInfo->getFunction()->begin());
}

static nodes_iterator nodes_end(DOTFuncMSSAInfo *CFGInfo) {
  return nodes_iterator(CFGInfo->getFunction()->end());
}

static size_t size(DOTFuncMSSAInfo *CFGInfo) {
  return CFGInfo->getFunction()->size();
}
2268};

2270template <>
2271struct DOTGraphTraits<DOTFuncMSSAInfo *> : public DefaultDOTGraphTraits {

DOTGraphTraits(bool IsSimple = false) : DefaultDOTGraphTraits(IsSimple) {}

static std::string getGraphName(DOTFuncMSSAInfo *CFGInfo) {
  return "MSSA CFG for '" + CFGInfo->getFunction()->getName().str() +
         "' function";
}

std::string getNodeLabel(const BasicBlock *Node, DOTFuncMSSAInfo *CFGInfo) {
  return DOTGraphTraits<DOTFuncInfo *>::getCompleteNodeLabel(
      Node, nullptr,
      [CFGInfo](raw_string_ostream &OS, const BasicBlock &BB) -> void {
        BB.print(OS, &CFGInfo->getWriter(), true, true);
      },
      [](std::string &S, unsigned &I, unsigned Idx) -> void {
        std::string Str = S.substr(I, Idx - I);
        StringRef SR = Str;
        if (SR.count(" = MemoryDef(") || SR.count(" = MemoryPhi(") ||
            SR.count("MemoryUse("))
          return;
        DOTGraphTraits<DOTFuncInfo *>::eraseComment(S, I, Idx);
      });
}

static std::string getEdgeSourceLabel(const BasicBlock *Node,
                                      const_succ_iterator I) {
  return DOTGraphTraits<DOTFuncInfo *>::getEdgeSourceLabel(Node, I);
}

/// Display the raw branch weights from PGO.
std::string getEdgeAttributes(const BasicBlock *Node, const_succ_iterator I,
                              DOTFuncMSSAInfo *CFGInfo) {
  return "";
}

std::string getNodeAttributes(const BasicBlock *Node,
                              DOTFuncMSSAInfo *CFGInfo) {
  return getNodeLabel(Node, CFGInfo).find(';') != std::string::npos
             ? "style=filled, fillcolor=lightpink"
             : "";
}
2313};

2315} // namespace llvm

2317bool MemorySSAPrinterLegacyPass::runOnFunction(Function &F) {
auto &MSSA = getAnalysis<MemorySSAWrapperPass>().getMSSA();
MSSA.ensureOptimizedUses();
if (DotCFGMSSA != "") {
  DOTFuncMSSAInfo CFGInfo(F, MSSA);
  WriteGraph(&CFGInfo, "", false, "MSSA", DotCFGMSSA);
} else
  MSSA.print(dbgs());

if (VerifyMemorySSA)
  MSSA.verifyMemorySSA();
return false;
2329}

2331AnalysisKey MemorySSAAnalysis::Key;

2333MemorySSAAnalysis::Result MemorySSAAnalysis::run(Function &F,
                                               FunctionAnalysisManager &AM) {
auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
auto &AA = AM.getResult<AAManager>(F);
return MemorySSAAnalysis::Result(std::make_unique<MemorySSA>(F, &AA, &DT));
2338}

2340bool MemorySSAAnalysis::Result::invalidate(
  Function &F, const PreservedAnalyses &PA,
  FunctionAnalysisManager::Invalidator &Inv) {
auto PAC = PA.getChecker<MemorySSAAnalysis>();
return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>()) ||
       Inv.invalidate<AAManager>(F, PA) ||
       Inv.invalidate<DominatorTreeAnalysis>(F, PA);
2347}

2349PreservedAnalyses MemorySSAPrinterPass::run(Function &F,
                                          FunctionAnalysisManager &AM) {
auto &MSSA = AM.getResult<MemorySSAAnalysis>(F).getMSSA();
MSSA.ensureOptimizedUses();
if (DotCFGMSSA != "") {
  DOTFuncMSSAInfo CFGInfo(F, MSSA);
  WriteGraph(&CFGInfo, "", false, "MSSA", DotCFGMSSA);
} else {
  OS << "MemorySSA for function: " << F.getName() << "\n";
  MSSA.print(OS);
}

return PreservedAnalyses::all();
2362}

2364PreservedAnalyses MemorySSAWalkerPrinterPass::run(Function &F,
                                                FunctionAnalysisManager &AM) {
auto &MSSA = AM.getResult<MemorySSAAnalysis>(F).getMSSA();
OS << "MemorySSA (walker) for function: " << F.getName() << "\n";
MemorySSAWalkerAnnotatedWriter Writer(&MSSA);
F.print(OS, &Writer);

return PreservedAnalyses::all();
2372}

2374PreservedAnalyses MemorySSAVerifierPass::run(Function &F,
                                           FunctionAnalysisManager &AM) {
AM.getResult<MemorySSAAnalysis>(F).getMSSA().verifyMemorySSA();

return PreservedAnalyses::all();
2379}

2381char MemorySSAWrapperPass::ID = 0;

2383MemorySSAWrapperPass::MemorySSAWrapperPass() : FunctionPass(ID) {
initializeMemorySSAWrapperPassPass(*PassRegistry::getPassRegistry());
2385}

2387void MemorySSAWrapperPass::releaseMemory() { MSSA.reset(); }

2389void MemorySSAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequiredTransitive<DominatorTreeWrapperPass>();
AU.addRequiredTransitive<AAResultsWrapperPass>();
2393}

2395bool MemorySSAWrapperPass::runOnFunction(Function &F) {
auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
MSSA.reset(new MemorySSA(F, &AA, &DT));
return false;
2400}

2402void MemorySSAWrapperPass::verifyAnalysis() const {
if (VerifyMemorySSA)
1
Assuming 'VerifyMemorySSA' is true→
2
←
Taking true branch→
  MSSA->verifyMemorySSA();
3
←
Calling 'MemorySSA::verifyMemorySSA'→
2405}

2407void MemorySSAWrapperPass::print(raw_ostream &OS, const Module *M) const {
MSSA->print(OS);
2409}

2411MemorySSAWalker::MemorySSAWalker(MemorySSA *M) : MSSA(M) {}

2413/// Walk the use-def chains starting at \p StartingAccess and find
2414/// the MemoryAccess that actually clobbers Loc.
2415///
2416/// \returns our clobbering memory access
2417MemoryAccess *MemorySSA::ClobberWalkerBase::getClobberingMemoryAccessBase(
  MemoryAccess *StartingAccess, const MemoryLocation &Loc,
  BatchAAResults &BAA, unsigned &UpwardWalkLimit) {
assert(!isa<MemoryUse>(StartingAccess) && "Use cannot be defining access")(static_cast <bool> (!isa<MemoryUse>(StartingAccess
) && "Use cannot be defining access") ? void (0) : __assert_fail
 ("!isa<MemoryUse>(StartingAccess) && \"Use cannot be defining access\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2420, __extension__ __PRETTY_FUNCTION__
));

Instruction *I = nullptr;
if (auto *StartingUseOrDef = dyn_cast<MemoryUseOrDef>(StartingAccess)) {
  if (MSSA->isLiveOnEntryDef(StartingUseOrDef))
    return StartingUseOrDef;

  I = StartingUseOrDef->getMemoryInst();

  // Conservatively, fences are always clobbers, so don't perform the walk if
  // we hit a fence.
  if (!isa<CallBase>(I) && I->isFenceLike())
    return StartingUseOrDef;
}

UpwardsMemoryQuery Q;
Q.OriginalAccess = StartingAccess;
Q.StartingLoc = Loc;
Q.Inst = nullptr;
Q.IsCall = false;

// Unlike the other function, do not walk to the def of a def, because we are
// handed something we already believe is the clobbering access.
// We never set SkipSelf to true in Q in this method.
MemoryAccess *Clobber =
    Walker.findClobber(BAA, StartingAccess, Q, UpwardWalkLimit);
LLVM_DEBUG({do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { { dbgs() << "Clobber starting at access "
 << *StartingAccess << "\n"; if (I) dbgs() <<
 "  for instruction " << *I << "\n"; dbgs() <<
 "  is " << *Clobber << "\n"; }; } } while (false
)
  dbgs() << "Clobber starting at access " << *StartingAccess << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { { dbgs() << "Clobber starting at access "
 << *StartingAccess << "\n"; if (I) dbgs() <<
 "  for instruction " << *I << "\n"; dbgs() <<
 "  is " << *Clobber << "\n"; }; } } while (false
)
  if (I)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { { dbgs() << "Clobber starting at access "
 << *StartingAccess << "\n"; if (I) dbgs() <<
 "  for instruction " << *I << "\n"; dbgs() <<
 "  is " << *Clobber << "\n"; }; } } while (false
)
    dbgs() << "  for instruction " << *I << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { { dbgs() << "Clobber starting at access "
 << *StartingAccess << "\n"; if (I) dbgs() <<
 "  for instruction " << *I << "\n"; dbgs() <<
 "  is " << *Clobber << "\n"; }; } } while (false
)
  dbgs() << "  is " << *Clobber << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { { dbgs() << "Clobber starting at access "
 << *StartingAccess << "\n"; if (I) dbgs() <<
 "  for instruction " << *I << "\n"; dbgs() <<
 "  is " << *Clobber << "\n"; }; } } while (false
)
})do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { { dbgs() << "Clobber starting at access "
 << *StartingAccess << "\n"; if (I) dbgs() <<
 "  for instruction " << *I << "\n"; dbgs() <<
 "  is " << *Clobber << "\n"; }; } } while (false
);
return Clobber;
2453}

2455static const Instruction *
2456getInvariantGroupClobberingInstruction(Instruction &I, DominatorTree &DT) {
if (!I.hasMetadata(LLVMContext::MD_invariant_group) || I.isVolatile())
  return nullptr;

// We consider bitcasts and zero GEPs to be the same pointer value. Start by
// stripping bitcasts and zero GEPs, then we will recursively look at loads
// and stores through bitcasts and zero GEPs.
Value *PointerOperand = getLoadStorePointerOperand(&I)->stripPointerCasts();

// It's not safe to walk the use list of a global value because function
// passes aren't allowed to look outside their functions.
// FIXME: this could be fixed by filtering instructions from outside of
// current function.
if (isa<Constant>(PointerOperand))
  return nullptr;

// Queue to process all pointers that are equivalent to load operand.
SmallVector<const Value *, 8> PointerUsesQueue;
PointerUsesQueue.push_back(PointerOperand);

const Instruction *MostDominatingInstruction = &I;

// FIXME: This loop is O(n^2) because dominates can be O(n) and in worst case
// we will see all the instructions. It may not matter in practice. If it
// does, we will have to support MemorySSA construction and updates.
while (!PointerUsesQueue.empty()) {
  const Value *Ptr = PointerUsesQueue.pop_back_val();
  assert(Ptr && !isa<GlobalValue>(Ptr) &&(static_cast <bool> (Ptr && !isa<GlobalValue
>(Ptr) && "Null or GlobalValue should not be inserted"
) ? void (0) : __assert_fail ("Ptr && !isa<GlobalValue>(Ptr) && \"Null or GlobalValue should not be inserted\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2484, __extension__ __PRETTY_FUNCTION__
))
         "Null or GlobalValue should not be inserted")(static_cast <bool> (Ptr && !isa<GlobalValue
>(Ptr) && "Null or GlobalValue should not be inserted"
) ? void (0) : __assert_fail ("Ptr && !isa<GlobalValue>(Ptr) && \"Null or GlobalValue should not be inserted\""
, "llvm/lib/Analysis/MemorySSA.cpp", 2484, __extension__ __PRETTY_FUNCTION__
));

  for (const User *Us : Ptr->users()) {
    auto *U = dyn_cast<Instruction>(Us);
    if (!U || U == &I || !DT.dominates(U, MostDominatingInstruction))
      continue;

    // Add bitcasts and zero GEPs to queue.
    if (isa<BitCastInst>(U)) {
      PointerUsesQueue.push_back(U);
      continue;
    }
    if (auto *GEP = dyn_cast<GetElementPtrInst>(U)) {
      if (GEP->hasAllZeroIndices())
        PointerUsesQueue.push_back(U);
      continue;
    }

    // If we hit a load/store with an invariant.group metadata and the same
    // pointer operand, we can assume that value pointed to by the pointer
    // operand didn't change.
    if (U->hasMetadata(LLVMContext::MD_invariant_group) &&
        getLoadStorePointerOperand(U) == Ptr && !U->isVolatile()) {
      MostDominatingInstruction = U;
    }
  }
}
return MostDominatingInstruction == &I ? nullptr : MostDominatingInstruction;
2512}

2514MemoryAccess *MemorySSA::ClobberWalkerBase::getClobberingMemoryAccessBase(
  MemoryAccess *MA, BatchAAResults &BAA, unsigned &UpwardWalkLimit,
  bool SkipSelf, bool UseInvariantGroup) {
auto *StartingAccess = dyn_cast<MemoryUseOrDef>(MA);
// If this is a MemoryPhi, we can't do anything.
if (!StartingAccess)
  return MA;

if (UseInvariantGroup) {
  if (auto *I = getInvariantGroupClobberingInstruction(
          *StartingAccess->getMemoryInst(), MSSA->getDomTree())) {
    assert(isa<LoadInst>(I) || isa<StoreInst>(I))(static_cast <bool> (isa<LoadInst>(I) || isa<StoreInst
>(I)) ? void (0) : __assert_fail ("isa<LoadInst>(I) || isa<StoreInst>(I)"
, "llvm/lib/Analysis/MemorySSA.cpp", 2525, __extension__ __PRETTY_FUNCTION__
));

    auto *ClobberMA = MSSA->getMemoryAccess(I);
    assert(ClobberMA)(static_cast <bool> (ClobberMA) ? void (0) : __assert_fail
 ("ClobberMA", "llvm/lib/Analysis/MemorySSA.cpp", 2528, __extension__
 __PRETTY_FUNCTION__));
    if (isa<MemoryUse>(ClobberMA))
      return ClobberMA->getDefiningAccess();
    return ClobberMA;
  }
}

bool IsOptimized = false;

// If this is an already optimized use or def, return the optimized result.
// Note: Currently, we store the optimized def result in a separate field,
// since we can't use the defining access.
if (StartingAccess->isOptimized()) {
  if (!SkipSelf || !isa<MemoryDef>(StartingAccess))
    return StartingAccess->getOptimized();
  IsOptimized = true;
}

const Instruction *I = StartingAccess->getMemoryInst();
// We can't sanely do anything with a fence, since they conservatively clobber
// all memory, and have no locations to get pointers from to try to
// disambiguate.
if (!isa<CallBase>(I) && I->isFenceLike())
  return StartingAccess;

UpwardsMemoryQuery Q(I, StartingAccess);

if (isUseTriviallyOptimizableToLiveOnEntry(BAA, I)) {
  MemoryAccess *LiveOnEntry = MSSA->getLiveOnEntryDef();
  StartingAccess->setOptimized(LiveOnEntry);
  return LiveOnEntry;
}

MemoryAccess *OptimizedAccess;
if (!IsOptimized) {
  // Start with the thing we already think clobbers this location
  MemoryAccess *DefiningAccess = StartingAccess->getDefiningAccess();

  // At this point, DefiningAccess may be the live on entry def.
  // If it is, we will not get a better result.
  if (MSSA->isLiveOnEntryDef(DefiningAccess)) {
    StartingAccess->setOptimized(DefiningAccess);
    return DefiningAccess;
  }

  OptimizedAccess =
      Walker.findClobber(BAA, DefiningAccess, Q, UpwardWalkLimit);
  StartingAccess->setOptimized(OptimizedAccess);
} else
  OptimizedAccess = StartingAccess->getOptimized();

LLVM_DEBUG(dbgs() << "Starting Memory SSA clobber for " << *I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "Starting Memory SSA clobber for "
 << *I << " is "; } } while (false);
LLVM_DEBUG(dbgs() << *StartingAccess << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *StartingAccess << "\n"
; } } while (false);
LLVM_DEBUG(dbgs() << "Optimized Memory SSA clobber for " << *I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "Optimized Memory SSA clobber for "
 << *I << " is "; } } while (false);
LLVM_DEBUG(dbgs() << *OptimizedAccess << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *OptimizedAccess << "\n"
; } } while (false);

MemoryAccess *Result;
if (SkipSelf && isa<MemoryPhi>(OptimizedAccess) &&
    isa<MemoryDef>(StartingAccess) && UpwardWalkLimit) {
  assert(isa<MemoryDef>(Q.OriginalAccess))(static_cast <bool> (isa<MemoryDef>(Q.OriginalAccess
)) ? void (0) : __assert_fail ("isa<MemoryDef>(Q.OriginalAccess)"
, "llvm/lib/Analysis/MemorySSA.cpp", 2587, __extension__ __PRETTY_FUNCTION__
));
  Q.SkipSelfAccess = true;
  Result = Walker.findClobber(BAA, OptimizedAccess, Q, UpwardWalkLimit);
} else
  Result = OptimizedAccess;

LLVM_DEBUG(dbgs() << "Result Memory SSA clobber [SkipSelf = " << SkipSelf)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "Result Memory SSA clobber [SkipSelf = "
 << SkipSelf; } } while (false);
LLVM_DEBUG(dbgs() << "] for " << *I << " is " << *Result << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "] for " << *I <<
 " is " << *Result << "\n"; } } while (false);

return Result;
2597}

2599MemoryAccess *
2600DoNothingMemorySSAWalker::getClobberingMemoryAccess(MemoryAccess *MA,
                                                  BatchAAResults &) {
if (auto *Use = dyn_cast<MemoryUseOrDef>(MA))
  return Use->getDefiningAccess();
return MA;
2605}

2607MemoryAccess *DoNothingMemorySSAWalker::getClobberingMemoryAccess(
  MemoryAccess *StartingAccess, const MemoryLocation &, BatchAAResults &) {
if (auto *Use = dyn_cast<MemoryUseOrDef>(StartingAccess))
  return Use->getDefiningAccess();
return StartingAccess;
2612}

2614void MemoryPhi::deleteMe(DerivedUser *Self) {
delete static_cast<MemoryPhi *>(Self);
2616}

2618void MemoryDef::deleteMe(DerivedUser *Self) {
delete static_cast<MemoryDef *>(Self);
2620}

2622void MemoryUse::deleteMe(DerivedUser *Self) {
delete static_cast<MemoryUse *>(Self);
2624}

2626bool upward_defs_iterator::IsGuaranteedLoopInvariant(const Value *Ptr) const {
auto IsGuaranteedLoopInvariantBase = [](const Value *Ptr) {
  Ptr = Ptr->stripPointerCasts();
  if (!isa<Instruction>(Ptr))
    return true;
  return isa<AllocaInst>(Ptr);
};

Ptr = Ptr->stripPointerCasts();
if (auto *I = dyn_cast<Instruction>(Ptr)) {
  if (I->getParent()->isEntryBlock())
    return true;
}
if (auto *GEP = dyn_cast<GEPOperator>(Ptr)) {
  return IsGuaranteedLoopInvariantBase(GEP->getPointerOperand()) &&
         GEP->hasAllConstantIndices();
}
return IsGuaranteedLoopInvariantBase(Ptr);
2644}

←

/build/source/llvm/include/llvm/Analysis/MemorySSA.h

1//===- MemorySSA.h - Build Memory SSA ---------------------------*- C++ -*-===//
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/// \file
10/// This file exposes an interface to building/using memory SSA to
11/// walk memory instructions using a use/def graph.
12///
13/// Memory SSA class builds an SSA form that links together memory access
14/// instructions such as loads, stores, atomics, and calls. Additionally, it
15/// does a trivial form of "heap versioning" Every time the memory state changes
16/// in the program, we generate a new heap version. It generates
17/// MemoryDef/Uses/Phis that are overlayed on top of the existing instructions.
18///
19/// As a trivial example,
20/// define i32 @main() #0 {
21/// entry:
22///   %call = call noalias i8* @_Znwm(i64 4) #2
23///   %0 = bitcast i8* %call to i32*
24///   %call1 = call noalias i8* @_Znwm(i64 4) #2
25///   %1 = bitcast i8* %call1 to i32*
26///   store i32 5, i32* %0, align 4
27///   store i32 7, i32* %1, align 4
28///   %2 = load i32* %0, align 4
29///   %3 = load i32* %1, align 4
30///   %add = add nsw i32 %2, %3
31///   ret i32 %add
32/// }
33///
34/// Will become
35/// define i32 @main() #0 {
36/// entry:
37///   ; 1 = MemoryDef(0)
38///   %call = call noalias i8* @_Znwm(i64 4) #3
39///   %2 = bitcast i8* %call to i32*
40///   ; 2 = MemoryDef(1)
41///   %call1 = call noalias i8* @_Znwm(i64 4) #3
42///   %4 = bitcast i8* %call1 to i32*
43///   ; 3 = MemoryDef(2)
44///   store i32 5, i32* %2, align 4
45///   ; 4 = MemoryDef(3)
46///   store i32 7, i32* %4, align 4
47///   ; MemoryUse(3)
48///   %7 = load i32* %2, align 4
49///   ; MemoryUse(4)
50///   %8 = load i32* %4, align 4
51///   %add = add nsw i32 %7, %8
52///   ret i32 %add
53/// }
54///
55/// Given this form, all the stores that could ever effect the load at %8 can be
56/// gotten by using the MemoryUse associated with it, and walking from use to
57/// def until you hit the top of the function.
58///
59/// Each def also has a list of users associated with it, so you can walk from
60/// both def to users, and users to defs. Note that we disambiguate MemoryUses,
61/// but not the RHS of MemoryDefs. You can see this above at %7, which would
62/// otherwise be a MemoryUse(4). Being disambiguated means that for a given
63/// store, all the MemoryUses on its use lists are may-aliases of that store
64/// (but the MemoryDefs on its use list may not be).
65///
66/// MemoryDefs are not disambiguated because it would require multiple reaching
67/// definitions, which would require multiple phis, and multiple memoryaccesses
68/// per instruction.
69///
70/// In addition to the def/use graph described above, MemoryDefs also contain
71/// an "optimized" definition use.  The "optimized" use points to some def
72/// reachable through the memory def chain.  The optimized def *may* (but is
73/// not required to) alias the original MemoryDef, but no def *closer* to the
74/// source def may alias it.  As the name implies, the purpose of the optimized
75/// use is to allow caching of clobber searches for memory defs.  The optimized
76/// def may be nullptr, in which case clients must walk the defining access
77/// chain.
78///
79/// When iterating the uses of a MemoryDef, both defining uses and optimized
80/// uses will be encountered.  If only one type is needed, the client must
81/// filter the use walk.
82//
83//===----------------------------------------------------------------------===//
84 
85#ifndef LLVM_ANALYSIS_MEMORYSSA_H
86#define LLVM_ANALYSIS_MEMORYSSA_H
87 
88#include "llvm/ADT/DenseMap.h"
89#include "llvm/ADT/SmallPtrSet.h"
90#include "llvm/ADT/SmallVector.h"
91#include "llvm/ADT/ilist_node.h"
92#include "llvm/ADT/iterator_range.h"
93#include "llvm/Analysis/AliasAnalysis.h"
94#include "llvm/Analysis/MemoryLocation.h"
95#include "llvm/Analysis/PHITransAddr.h"
96#include "llvm/IR/DerivedUser.h"
97#include "llvm/IR/Dominators.h"
98#include "llvm/IR/Type.h"
99#include "llvm/IR/User.h"
100#include "llvm/Pass.h"
101#include <algorithm>
102#include <cassert>
103#include <cstddef>
104#include <iterator>
105#include <memory>
106#include <utility>
107 
108namespace llvm {
109 
110template <class GraphType> struct GraphTraits;
111class BasicBlock;
112class Function;
113class Instruction;
114class LLVMContext;
115class MemoryAccess;
116class MemorySSAWalker;
117class Module;
118class Use;
119class Value;
120class raw_ostream;
121 
122namespace MSSAHelpers {
123 
124struct AllAccessTag {};
125struct DefsOnlyTag {};
126 
127} // end namespace MSSAHelpers
128 
129enum : unsigned {
130  // Used to signify what the default invalid ID is for MemoryAccess's
131  // getID()
132  INVALID_MEMORYACCESS_ID = -1U
133};
134 
135template <class T> class memoryaccess_def_iterator_base;
136using memoryaccess_def_iterator = memoryaccess_def_iterator_base<MemoryAccess>;
137using const_memoryaccess_def_iterator =
138    memoryaccess_def_iterator_base<const MemoryAccess>;
139 
140// The base for all memory accesses. All memory accesses in a block are
141// linked together using an intrusive list.
142class MemoryAccess
143    : public DerivedUser,
144      public ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::AllAccessTag>>,
145      public ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::DefsOnlyTag>> {
146public:
147  using AllAccessType =
148      ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::AllAccessTag>>;
149  using DefsOnlyType =
150      ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::DefsOnlyTag>>;
151 
152  MemoryAccess(const MemoryAccess &) = delete;
153  MemoryAccess &operator=(const MemoryAccess &) = delete;
154 
155  void *operator new(size_t) = delete;
156 
157  // Methods for support type inquiry through isa, cast, and
158  // dyn_cast
159  static bool classof(const Value *V) {
160    unsigned ID = V->getValueID();
161    return ID == MemoryUseVal || ID == MemoryPhiVal || ID == MemoryDefVal;
162  }
163 
164  BasicBlock *getBlock() const { return Block; }
165 
166  void print(raw_ostream &OS) const;
167  void dump() const;
168 
169  /// The user iterators for a memory access
170  using iterator = user_iterator;
171  using const_iterator = const_user_iterator;
172 
173  /// This iterator walks over all of the defs in a given
174  /// MemoryAccess. For MemoryPhi nodes, this walks arguments. For
175  /// MemoryUse/MemoryDef, this walks the defining access.
176  memoryaccess_def_iterator defs_begin();
177  const_memoryaccess_def_iterator defs_begin() const;
178  memoryaccess_def_iterator defs_end();
179  const_memoryaccess_def_iterator defs_end() const;
180 
181  /// Get the iterators for the all access list and the defs only list
182  /// We default to the all access list.
183  AllAccessType::self_iterator getIterator() {
184    return this->AllAccessType::getIterator();
185  }
186  AllAccessType::const_self_iterator getIterator() const {
187    return this->AllAccessType::getIterator();
188  }
189  AllAccessType::reverse_self_iterator getReverseIterator() {
190    return this->AllAccessType::getReverseIterator();
191  }
192  AllAccessType::const_reverse_self_iterator getReverseIterator() const {
193    return this->AllAccessType::getReverseIterator();
194  }
195  DefsOnlyType::self_iterator getDefsIterator() {
196    return this->DefsOnlyType::getIterator();
197  }
198  DefsOnlyType::const_self_iterator getDefsIterator() const {
199    return this->DefsOnlyType::getIterator();
200  }
201  DefsOnlyType::reverse_self_iterator getReverseDefsIterator() {
202    return this->DefsOnlyType::getReverseIterator();
203  }
204  DefsOnlyType::const_reverse_self_iterator getReverseDefsIterator() const {
205    return this->DefsOnlyType::getReverseIterator();
206  }
207 
208protected:
209  friend class MemoryDef;
210  friend class MemoryPhi;
211  friend class MemorySSA;
212  friend class MemoryUse;
213  friend class MemoryUseOrDef;
214 
215  /// Used by MemorySSA to change the block of a MemoryAccess when it is
216  /// moved.
217  void setBlock(BasicBlock *BB) { Block = BB; }
218 
219  /// Used for debugging and tracking things about MemoryAccesses.
220  /// Guaranteed unique among MemoryAccesses, no guarantees otherwise.
221  inline unsigned getID() const;
222 
223  MemoryAccess(LLVMContext &C, unsigned Vty, DeleteValueTy DeleteValue,
224               BasicBlock *BB, unsigned NumOperands)
225      : DerivedUser(Type::getVoidTy(C), Vty, nullptr, NumOperands, DeleteValue),
226        Block(BB) {}
227 
228  // Use deleteValue() to delete a generic MemoryAccess.
229  ~MemoryAccess() = default;
230 
231private:
232  BasicBlock *Block;
233};
234 
235template <>
236struct ilist_alloc_traits<MemoryAccess> {
237  static void deleteNode(MemoryAccess *MA) { MA->deleteValue(); }
238};
239 
240inline raw_ostream &operator<<(raw_ostream &OS, const MemoryAccess &MA) {
241  MA.print(OS);
242  return OS;
243}
244 
245/// Class that has the common methods + fields of memory uses/defs. It's
246/// a little awkward to have, but there are many cases where we want either a
247/// use or def, and there are many cases where uses are needed (defs aren't
248/// acceptable), and vice-versa.
249///
250/// This class should never be instantiated directly; make a MemoryUse or
251/// MemoryDef instead.
252class MemoryUseOrDef : public MemoryAccess {
253public:
254  void *operator new(size_t) = delete;
255 
256  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(MemoryAccess)public: inline MemoryAccess *getOperand(unsigned) const; inline
 void setOperand(unsigned, MemoryAccess*); inline op_iterator
 op_begin(); inline const_op_iterator op_begin() const; inline
 op_iterator op_end(); inline const_op_iterator op_end() const
; protected: template <int> inline Use &Op(); template
 <int> inline const Use &Op() const; public: inline
 unsigned getNumOperands() const;
257 
258  /// Get the instruction that this MemoryUse represents.
259  Instruction *getMemoryInst() const { return MemoryInstruction; }
260 
261  /// Get the access that produces the memory state used by this Use.
262  MemoryAccess *getDefiningAccess() const { return getOperand(0); }
263 
264  static bool classof(const Value *MA) {
265    return MA->getValueID() == MemoryUseVal || MA->getValueID() == MemoryDefVal;
266  }
267 
268  /// Do we have an optimized use?
269  inline bool isOptimized() const;
270  /// Return the MemoryAccess associated with the optimized use, or nullptr.
271  inline MemoryAccess *getOptimized() const;
272  /// Sets the optimized use for a MemoryDef.
273  inline void setOptimized(MemoryAccess *);
274 
275  /// Reset the ID of what this MemoryUse was optimized to, causing it to
276  /// be rewalked by the walker if necessary.
277  /// This really should only be called by tests.
278  inline void resetOptimized();
279 
280protected:
281  friend class MemorySSA;
282  friend class MemorySSAUpdater;
283 
284  MemoryUseOrDef(LLVMContext &C, MemoryAccess *DMA, unsigned Vty,
285                 DeleteValueTy DeleteValue, Instruction *MI, BasicBlock *BB,
286                 unsigned NumOperands)
287      : MemoryAccess(C, Vty, DeleteValue, BB, NumOperands),
288        MemoryInstruction(MI) {
289    setDefiningAccess(DMA);
290  }
291 
292  // Use deleteValue() to delete a generic MemoryUseOrDef.
293  ~MemoryUseOrDef() = default;
294 
295  void setDefiningAccess(MemoryAccess *DMA, bool Optimized = false) {
296    if (!Optimized) {
297      setOperand(0, DMA);
298      return;
299    }
300    setOptimized(DMA);
301  }
302 
303private:
304  Instruction *MemoryInstruction;
305};
306 
307/// Represents read-only accesses to memory
308///
309/// In particular, the set of Instructions that will be represented by
310/// MemoryUse's is exactly the set of Instructions for which
311/// AliasAnalysis::getModRefInfo returns "Ref".
312class MemoryUse final : public MemoryUseOrDef {
313public:
314  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(MemoryAccess)public: inline MemoryAccess *getOperand(unsigned) const; inline
 void setOperand(unsigned, MemoryAccess*); inline op_iterator
 op_begin(); inline const_op_iterator op_begin() const; inline
 op_iterator op_end(); inline const_op_iterator op_end() const
; protected: template <int> inline Use &Op(); template
 <int> inline const Use &Op() const; public: inline
 unsigned getNumOperands() const;
315 
316  MemoryUse(LLVMContext &C, MemoryAccess *DMA, Instruction *MI, BasicBlock *BB)
317      : MemoryUseOrDef(C, DMA, MemoryUseVal, deleteMe, MI, BB,
318                       /*NumOperands=*/1) {}
319 
320  // allocate space for exactly one operand
321  void *operator new(size_t S) { return User::operator new(S, 1); }
322  void operator delete(void *Ptr) { User::operator delete(Ptr); }
323 
324  static bool classof(const Value *MA) {
325    return MA->getValueID() == MemoryUseVal;
326  }
327 
328  void print(raw_ostream &OS) const;
329 
330  void setOptimized(MemoryAccess *DMA) {
331    OptimizedID = DMA->getID();
332    setOperand(0, DMA);
333  }
334 
335  /// Whether the MemoryUse is optimized. If ensureOptimizedUses() was called,
336  /// uses will usually be optimized, but this is not guaranteed (e.g. due to
337  /// invalidation and optimization limits.)
338  bool isOptimized() const {
339    return getDefiningAccess() && OptimizedID == getDefiningAccess()->getID();
340  }
341 
342  MemoryAccess *getOptimized() const {
343    return getDefiningAccess();
344  }
345 
346  void resetOptimized() {
347    OptimizedID = INVALID_MEMORYACCESS_ID;
348  }
349 
350protected:
351  friend class MemorySSA;
352 
353private:
354  static void deleteMe(DerivedUser *Self);
355 
356  unsigned OptimizedID = INVALID_MEMORYACCESS_ID;
357};
358 
359template <>
360struct OperandTraits<MemoryUse> : public FixedNumOperandTraits<MemoryUse, 1> {};
361DEFINE_TRANSPARENT_OPERAND_ACCESSORS(MemoryUse, MemoryAccess)MemoryUse::op_iterator MemoryUse::op_begin() { return OperandTraits
<MemoryUse>::op_begin(this); } MemoryUse::const_op_iterator
 MemoryUse::op_begin() const { return OperandTraits<MemoryUse
>::op_begin(const_cast<MemoryUse*>(this)); } MemoryUse
::op_iterator MemoryUse::op_end() { return OperandTraits<MemoryUse
>::op_end(this); } MemoryUse::const_op_iterator MemoryUse::
op_end() const { return OperandTraits<MemoryUse>::op_end
(const_cast<MemoryUse*>(this)); } MemoryAccess *MemoryUse
::getOperand(unsigned i_nocapture) const { (static_cast <bool
> (i_nocapture < OperandTraits<MemoryUse>::operands
(this) && "getOperand() out of range!") ? void (0) : __assert_fail
 ("i_nocapture < OperandTraits<MemoryUse>::operands(this) && \"getOperand() out of range!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 361, __extension__
 __PRETTY_FUNCTION__)); return cast_or_null<MemoryAccess>
( OperandTraits<MemoryUse>::op_begin(const_cast<MemoryUse
*>(this))[i_nocapture].get()); } void MemoryUse::setOperand
(unsigned i_nocapture, MemoryAccess *Val_nocapture) { (static_cast
 <bool> (i_nocapture < OperandTraits<MemoryUse>
::operands(this) && "setOperand() out of range!") ? void
 (0) : __assert_fail ("i_nocapture < OperandTraits<MemoryUse>::operands(this) && \"setOperand() out of range!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 361, __extension__
 __PRETTY_FUNCTION__)); OperandTraits<MemoryUse>::op_begin
(this)[i_nocapture] = Val_nocapture; } unsigned MemoryUse::getNumOperands
() const { return OperandTraits<MemoryUse>::operands(this
); } template <int Idx_nocapture> Use &MemoryUse::Op
() { return this->OpFrom<Idx_nocapture>(this); } template
 <int Idx_nocapture> const Use &MemoryUse::Op() const
 { return this->OpFrom<Idx_nocapture>(this); }
362 
363/// Represents a read-write access to memory, whether it is a must-alias,
364/// or a may-alias.
365///
366/// In particular, the set of Instructions that will be represented by
367/// MemoryDef's is exactly the set of Instructions for which
368/// AliasAnalysis::getModRefInfo returns "Mod" or "ModRef".
369/// Note that, in order to provide def-def chains, all defs also have a use
370/// associated with them. This use points to the nearest reaching
371/// MemoryDef/MemoryPhi.
372class MemoryDef final : public MemoryUseOrDef {
373public:
374  friend class MemorySSA;
375 
376  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(MemoryAccess)public: inline MemoryAccess *getOperand(unsigned) const; inline
 void setOperand(unsigned, MemoryAccess*); inline op_iterator
 op_begin(); inline const_op_iterator op_begin() const; inline
 op_iterator op_end(); inline const_op_iterator op_end() const
; protected: template <int> inline Use &Op(); template
 <int> inline const Use &Op() const; public: inline
 unsigned getNumOperands() const;
377 
378  MemoryDef(LLVMContext &C, MemoryAccess *DMA, Instruction *MI, BasicBlock *BB,
379            unsigned Ver)
380      : MemoryUseOrDef(C, DMA, MemoryDefVal, deleteMe, MI, BB,
381                       /*NumOperands=*/2),
382        ID(Ver) {}
383 
384  // allocate space for exactly two operands
385  void *operator new(size_t S) { return User::operator new(S, 2); }
386  void operator delete(void *Ptr) { User::operator delete(Ptr); }
387 
388  static bool classof(const Value *MA) {
389    return MA->getValueID() == MemoryDefVal;
390  }
391 
392  void setOptimized(MemoryAccess *MA) {
393    setOperand(1, MA);
394    OptimizedID = MA->getID();
395  }
396 
397  MemoryAccess *getOptimized() const {
398    return cast_or_null<MemoryAccess>(getOperand(1));
399  }
400 
401  bool isOptimized() const {
402    return getOptimized() && OptimizedID == getOptimized()->getID();
403  }
404 
405  void resetOptimized() {
406    OptimizedID = INVALID_MEMORYACCESS_ID;
407    setOperand(1, nullptr);
408  }
409 
410  void print(raw_ostream &OS) const;
411 
412  unsigned getID() const { return ID; }
413 
414private:
415  static void deleteMe(DerivedUser *Self);
416 
417  const unsigned ID;
418  unsigned OptimizedID = INVALID_MEMORYACCESS_ID;
419};
420 
421template <>
422struct OperandTraits<MemoryDef> : public FixedNumOperandTraits<MemoryDef, 2> {};
423DEFINE_TRANSPARENT_OPERAND_ACCESSORS(MemoryDef, MemoryAccess)MemoryDef::op_iterator MemoryDef::op_begin() { return OperandTraits
<MemoryDef>::op_begin(this); } MemoryDef::const_op_iterator
 MemoryDef::op_begin() const { return OperandTraits<MemoryDef
>::op_begin(const_cast<MemoryDef*>(this)); } MemoryDef
::op_iterator MemoryDef::op_end() { return OperandTraits<MemoryDef
>::op_end(this); } MemoryDef::const_op_iterator MemoryDef::
op_end() const { return OperandTraits<MemoryDef>::op_end
(const_cast<MemoryDef*>(this)); } MemoryAccess *MemoryDef
::getOperand(unsigned i_nocapture) const { (static_cast <bool
> (i_nocapture < OperandTraits<MemoryDef>::operands
(this) && "getOperand() out of range!") ? void (0) : __assert_fail
 ("i_nocapture < OperandTraits<MemoryDef>::operands(this) && \"getOperand() out of range!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 423, __extension__
 __PRETTY_FUNCTION__)); return cast_or_null<MemoryAccess>
( OperandTraits<MemoryDef>::op_begin(const_cast<MemoryDef
*>(this))[i_nocapture].get()); } void MemoryDef::setOperand
(unsigned i_nocapture, MemoryAccess *Val_nocapture) { (static_cast
 <bool> (i_nocapture < OperandTraits<MemoryDef>
::operands(this) && "setOperand() out of range!") ? void
 (0) : __assert_fail ("i_nocapture < OperandTraits<MemoryDef>::operands(this) && \"setOperand() out of range!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 423, __extension__
 __PRETTY_FUNCTION__)); OperandTraits<MemoryDef>::op_begin
(this)[i_nocapture] = Val_nocapture; } unsigned MemoryDef::getNumOperands
() const { return OperandTraits<MemoryDef>::operands(this
); } template <int Idx_nocapture> Use &MemoryDef::Op
() { return this->OpFrom<Idx_nocapture>(this); } template
 <int Idx_nocapture> const Use &MemoryDef::Op() const
 { return this->OpFrom<Idx_nocapture>(this); }
424 
425template <>
426struct OperandTraits<MemoryUseOrDef> {
427  static Use *op_begin(MemoryUseOrDef *MUD) {
428    if (auto *MU = dyn_cast<MemoryUse>(MUD))
429      return OperandTraits<MemoryUse>::op_begin(MU);
430    return OperandTraits<MemoryDef>::op_begin(cast<MemoryDef>(MUD));
431  }
432 
433  static Use *op_end(MemoryUseOrDef *MUD) {
434    if (auto *MU = dyn_cast<MemoryUse>(MUD))
435      return OperandTraits<MemoryUse>::op_end(MU);
436    return OperandTraits<MemoryDef>::op_end(cast<MemoryDef>(MUD));
437  }
438 
439  static unsigned operands(const MemoryUseOrDef *MUD) {
440    if (const auto *MU = dyn_cast<MemoryUse>(MUD))
441      return OperandTraits<MemoryUse>::operands(MU);
442    return OperandTraits<MemoryDef>::operands(cast<MemoryDef>(MUD));
443  }
444};
445DEFINE_TRANSPARENT_OPERAND_ACCESSORS(MemoryUseOrDef, MemoryAccess)MemoryUseOrDef::op_iterator MemoryUseOrDef::op_begin() { return
 OperandTraits<MemoryUseOrDef>::op_begin(this); } MemoryUseOrDef
::const_op_iterator MemoryUseOrDef::op_begin() const { return
 OperandTraits<MemoryUseOrDef>::op_begin(const_cast<
MemoryUseOrDef*>(this)); } MemoryUseOrDef::op_iterator MemoryUseOrDef
::op_end() { return OperandTraits<MemoryUseOrDef>::op_end
(this); } MemoryUseOrDef::const_op_iterator MemoryUseOrDef::op_end
() const { return OperandTraits<MemoryUseOrDef>::op_end
(const_cast<MemoryUseOrDef*>(this)); } MemoryAccess *MemoryUseOrDef
::getOperand(unsigned i_nocapture) const { (static_cast <bool
> (i_nocapture < OperandTraits<MemoryUseOrDef>::operands
(this) && "getOperand() out of range!") ? void (0) : __assert_fail
 ("i_nocapture < OperandTraits<MemoryUseOrDef>::operands(this) && \"getOperand() out of range!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 445, __extension__
 __PRETTY_FUNCTION__)); return cast_or_null<MemoryAccess>
( OperandTraits<MemoryUseOrDef>::op_begin(const_cast<
MemoryUseOrDef*>(this))[i_nocapture].get()); } void MemoryUseOrDef
::setOperand(unsigned i_nocapture, MemoryAccess *Val_nocapture
) { (static_cast <bool> (i_nocapture < OperandTraits
<MemoryUseOrDef>::operands(this) && "setOperand() out of range!"
) ? void (0) : __assert_fail ("i_nocapture < OperandTraits<MemoryUseOrDef>::operands(this) && \"setOperand() out of range!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 445, __extension__
 __PRETTY_FUNCTION__)); OperandTraits<MemoryUseOrDef>::
op_begin(this)[i_nocapture] = Val_nocapture; } unsigned MemoryUseOrDef
::getNumOperands() const { return OperandTraits<MemoryUseOrDef
>::operands(this); } template <int Idx_nocapture> Use
 &MemoryUseOrDef::Op() { return this->OpFrom<Idx_nocapture
>(this); } template <int Idx_nocapture> const Use &
MemoryUseOrDef::Op() const { return this->OpFrom<Idx_nocapture
>(this); }
446 
447/// Represents phi nodes for memory accesses.
448///
449/// These have the same semantic as regular phi nodes, with the exception that
450/// only one phi will ever exist in a given basic block.
451/// Guaranteeing one phi per block means guaranteeing there is only ever one
452/// valid reaching MemoryDef/MemoryPHI along each path to the phi node.
453/// This is ensured by not allowing disambiguation of the RHS of a MemoryDef or
454/// a MemoryPhi's operands.
455/// That is, given
456/// if (a) {
457///   store %a
458///   store %b
459/// }
460/// it *must* be transformed into
461/// if (a) {
462///    1 = MemoryDef(liveOnEntry)
463///    store %a
464///    2 = MemoryDef(1)
465///    store %b
466/// }
467/// and *not*
468/// if (a) {
469///    1 = MemoryDef(liveOnEntry)
470///    store %a
471///    2 = MemoryDef(liveOnEntry)
472///    store %b
473/// }
474/// even if the two stores do not conflict. Otherwise, both 1 and 2 reach the
475/// end of the branch, and if there are not two phi nodes, one will be
476/// disconnected completely from the SSA graph below that point.
477/// Because MemoryUse's do not generate new definitions, they do not have this
478/// issue.
479class MemoryPhi final : public MemoryAccess {
480  // allocate space for exactly zero operands
481  void *operator new(size_t S) { return User::operator new(S); }
482 
483public:
484  void operator delete(void *Ptr) { User::operator delete(Ptr); }
485 
486  /// Provide fast operand accessors
487  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(MemoryAccess)public: inline MemoryAccess *getOperand(unsigned) const; inline
 void setOperand(unsigned, MemoryAccess*); inline op_iterator
 op_begin(); inline const_op_iterator op_begin() const; inline
 op_iterator op_end(); inline const_op_iterator op_end() const
; protected: template <int> inline Use &Op(); template
 <int> inline const Use &Op() const; public: inline
 unsigned getNumOperands() const;
488 
489  MemoryPhi(LLVMContext &C, BasicBlock *BB, unsigned Ver, unsigned NumPreds = 0)
490      : MemoryAccess(C, MemoryPhiVal, deleteMe, BB, 0), ID(Ver),
491        ReservedSpace(NumPreds) {
492    allocHungoffUses(ReservedSpace);
493  }
494 
495  // Block iterator interface. This provides access to the list of incoming
496  // basic blocks, which parallels the list of incoming values.
497  using block_iterator = BasicBlock **;
498  using const_block_iterator = BasicBlock *const *;
499 
500  block_iterator block_begin() {
501    return reinterpret_cast<block_iterator>(op_begin() + ReservedSpace);
502  }
503 
504  const_block_iterator block_begin() const {
505    return reinterpret_cast<const_block_iterator>(op_begin() + ReservedSpace);
506  }
507 
508  block_iterator block_end() { return block_begin() + getNumOperands(); }
509 
510  const_block_iterator block_end() const {
511    return block_begin() + getNumOperands();
512  }
513 
514  iterator_range<block_iterator> blocks() {
515    return make_range(block_begin(), block_end());
516  }
517 
518  iterator_range<const_block_iterator> blocks() const {
519    return make_range(block_begin(), block_end());
520  }
521 
522  op_range incoming_values() { return operands(); }
523 
524  const_op_range incoming_values() const { return operands(); }
525 
526  /// Return the number of incoming edges
527  unsigned getNumIncomingValues() const { return getNumOperands(); }
528 
529  /// Return incoming value number x
530  MemoryAccess *getIncomingValue(unsigned I) const { return getOperand(I); }
531  void setIncomingValue(unsigned I, MemoryAccess *V) {
532    assert(V && "PHI node got a null value!")(static_cast <bool> (V && "PHI node got a null value!"
) ? void (0) : __assert_fail ("V && \"PHI node got a null value!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 532, __extension__
 __PRETTY_FUNCTION__));
533    setOperand(I, V);
534  }
535 
536  static unsigned getOperandNumForIncomingValue(unsigned I) { return I; }
537  static unsigned getIncomingValueNumForOperand(unsigned I) { return I; }
538 
539  /// Return incoming basic block number @p i.
540  BasicBlock *getIncomingBlock(unsigned I) const { return block_begin()[I]; }
541 
542  /// Return incoming basic block corresponding
543  /// to an operand of the PHI.
544  BasicBlock *getIncomingBlock(const Use &U) const {
545    assert(this == U.getUser() && "Iterator doesn't point to PHI's Uses?")(static_cast <bool> (this == U.getUser() && "Iterator doesn't point to PHI's Uses?"
) ? void (0) : __assert_fail ("this == U.getUser() && \"Iterator doesn't point to PHI's Uses?\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 545, __extension__
 __PRETTY_FUNCTION__));
546    return getIncomingBlock(unsigned(&U - op_begin()));
547  }
548 
549  /// Return incoming basic block corresponding
550  /// to value use iterator.
551  BasicBlock *getIncomingBlock(MemoryAccess::const_user_iterator I) const {
552    return getIncomingBlock(I.getUse());
553  }
554 
555  void setIncomingBlock(unsigned I, BasicBlock *BB) {
556    assert(BB && "PHI node got a null basic block!")(static_cast <bool> (BB && "PHI node got a null basic block!"
) ? void (0) : __assert_fail ("BB && \"PHI node got a null basic block!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 556, __extension__
 __PRETTY_FUNCTION__));
557    block_begin()[I] = BB;
558  }
559 
560  /// Add an incoming value to the end of the PHI list
561  void addIncoming(MemoryAccess *V, BasicBlock *BB) {
562    if (getNumOperands() == ReservedSpace)
563      growOperands(); // Get more space!
564    // Initialize some new operands.
565    setNumHungOffUseOperands(getNumOperands() + 1);
566    setIncomingValue(getNumOperands() - 1, V);
567    setIncomingBlock(getNumOperands() - 1, BB);
568  }
569 
570  /// Return the first index of the specified basic
571  /// block in the value list for this PHI.  Returns -1 if no instance.
572  int getBasicBlockIndex(const BasicBlock *BB) const {
573    for (unsigned I = 0, E = getNumOperands(); I != E; ++I)
574      if (block_begin()[I] == BB)
575        return I;
576    return -1;
577  }
578 
579  MemoryAccess *getIncomingValueForBlock(const BasicBlock *BB) const {
580    int Idx = getBasicBlockIndex(BB);
581    assert(Idx >= 0 && "Invalid basic block argument!")(static_cast <bool> (Idx >= 0 && "Invalid basic block argument!"
) ? void (0) : __assert_fail ("Idx >= 0 && \"Invalid basic block argument!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 581, __extension__
 __PRETTY_FUNCTION__));
582    return getIncomingValue(Idx);
583  }
584 
585  // After deleting incoming position I, the order of incoming may be changed.
586  void unorderedDeleteIncoming(unsigned I) {
587    unsigned E = getNumOperands();
588    assert(I < E && "Cannot remove out of bounds Phi entry.")(static_cast <bool> (I < E && "Cannot remove out of bounds Phi entry."
) ? void (0) : __assert_fail ("I < E && \"Cannot remove out of bounds Phi entry.\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 588, __extension__
 __PRETTY_FUNCTION__));
589    // MemoryPhi must have at least two incoming values, otherwise the MemoryPhi
590    // itself should be deleted.
591    assert(E >= 2 && "Cannot only remove incoming values in MemoryPhis with "(static_cast <bool> (E >= 2 && "Cannot only remove incoming values in MemoryPhis with "
 "at least 2 values.") ? void (0) : __assert_fail ("E >= 2 && \"Cannot only remove incoming values in MemoryPhis with \" \"at least 2 values.\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 592, __extension__
 __PRETTY_FUNCTION__))
592                     "at least 2 values.")(static_cast <bool> (E >= 2 && "Cannot only remove incoming values in MemoryPhis with "
 "at least 2 values.") ? void (0) : __assert_fail ("E >= 2 && \"Cannot only remove incoming values in MemoryPhis with \" \"at least 2 values.\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 592, __extension__
 __PRETTY_FUNCTION__));
593    setIncomingValue(I, getIncomingValue(E - 1));
594    setIncomingBlock(I, block_begin()[E - 1]);
595    setOperand(E - 1, nullptr);
596    block_begin()[E - 1] = nullptr;
597    setNumHungOffUseOperands(getNumOperands() - 1);
598  }
599 
600  // After deleting entries that satisfy Pred, remaining entries may have
601  // changed order.
602  template <typename Fn> void unorderedDeleteIncomingIf(Fn &&Pred) {
603    for (unsigned I = 0, E = getNumOperands(); I != E; ++I)
604      if (Pred(getIncomingValue(I), getIncomingBlock(I))) {
605        unorderedDeleteIncoming(I);
606        E = getNumOperands();
607        --I;
608      }
609    assert(getNumOperands() >= 1 &&(static_cast <bool> (getNumOperands() >= 1 &&
 "Cannot remove all incoming blocks in a MemoryPhi.") ? void (
0) : __assert_fail ("getNumOperands() >= 1 && \"Cannot remove all incoming blocks in a MemoryPhi.\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 610, __extension__
 __PRETTY_FUNCTION__))
610           "Cannot remove all incoming blocks in a MemoryPhi.")(static_cast <bool> (getNumOperands() >= 1 &&
 "Cannot remove all incoming blocks in a MemoryPhi.") ? void (
0) : __assert_fail ("getNumOperands() >= 1 && \"Cannot remove all incoming blocks in a MemoryPhi.\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 610, __extension__
 __PRETTY_FUNCTION__));
611  }
612 
613  // After deleting incoming block BB, the incoming blocks order may be changed.
614  void unorderedDeleteIncomingBlock(const BasicBlock *BB) {
615    unorderedDeleteIncomingIf(
616        [&](const MemoryAccess *, const BasicBlock *B) { return BB == B; });
617  }
618 
619  // After deleting incoming memory access MA, the incoming accesses order may
620  // be changed.
621  void unorderedDeleteIncomingValue(const MemoryAccess *MA) {
622    unorderedDeleteIncomingIf(
623        [&](const MemoryAccess *M, const BasicBlock *) { return MA == M; });
624  }
625 
626  static bool classof(const Value *V) {
627    return V->getValueID() == MemoryPhiVal;
628  }
629 
630  void print(raw_ostream &OS) const;
631 
632  unsigned getID() const { return ID; }
633 
634protected:
635  friend class MemorySSA;
636 
637  /// this is more complicated than the generic
638  /// User::allocHungoffUses, because we have to allocate Uses for the incoming
639  /// values and pointers to the incoming blocks, all in one allocation.
640  void allocHungoffUses(unsigned N) {
641    User::allocHungoffUses(N, /* IsPhi */ true);
642  }
643 
644private:
645  // For debugging only
646  const unsigned ID;
647  unsigned ReservedSpace;
648 
649  /// This grows the operand list in response to a push_back style of
650  /// operation.  This grows the number of ops by 1.5 times.
651  void growOperands() {
652    unsigned E = getNumOperands();
653    // 2 op PHI nodes are VERY common, so reserve at least enough for that.
654    ReservedSpace = std::max(E + E / 2, 2u);
655    growHungoffUses(ReservedSpace, /* IsPhi */ true);
656  }
657 
658  static void deleteMe(DerivedUser *Self);
659};
660 
661inline unsigned MemoryAccess::getID() const {
662  assert((isa<MemoryDef>(this) || isa<MemoryPhi>(this)) &&(static_cast <bool> ((isa<MemoryDef>(this) || isa
<MemoryPhi>(this)) && "only memory defs and phis have ids"
) ? void (0) : __assert_fail ("(isa<MemoryDef>(this) || isa<MemoryPhi>(this)) && \"only memory defs and phis have ids\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 663, __extension__
 __PRETTY_FUNCTION__))
663         "only memory defs and phis have ids")(static_cast <bool> ((isa<MemoryDef>(this) || isa
<MemoryPhi>(this)) && "only memory defs and phis have ids"
) ? void (0) : __assert_fail ("(isa<MemoryDef>(this) || isa<MemoryPhi>(this)) && \"only memory defs and phis have ids\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 663, __extension__
 __PRETTY_FUNCTION__));
664  if (const auto *MD = dyn_cast<MemoryDef>(this))
665    return MD->getID();
666  return cast<MemoryPhi>(this)->getID();
667}
668 
669inline bool MemoryUseOrDef::isOptimized() const {
670  if (const auto *MD = dyn_cast<MemoryDef>(this))
671    return MD->isOptimized();
672  return cast<MemoryUse>(this)->isOptimized();
673}
674 
675inline MemoryAccess *MemoryUseOrDef::getOptimized() const {
676  if (const auto *MD = dyn_cast<MemoryDef>(this))
677    return MD->getOptimized();
678  return cast<MemoryUse>(this)->getOptimized();
679}
680 
681inline void MemoryUseOrDef::setOptimized(MemoryAccess *MA) {
682  if (auto *MD = dyn_cast<MemoryDef>(this))
683    MD->setOptimized(MA);
684  else
685    cast<MemoryUse>(this)->setOptimized(MA);
686}
687 
688inline void MemoryUseOrDef::resetOptimized() {
689  if (auto *MD = dyn_cast<MemoryDef>(this))
690    MD->resetOptimized();
691  else
692    cast<MemoryUse>(this)->resetOptimized();
693}
694 
695template <> struct OperandTraits<MemoryPhi> : public HungoffOperandTraits<2> {};
696DEFINE_TRANSPARENT_OPERAND_ACCESSORS(MemoryPhi, MemoryAccess)MemoryPhi::op_iterator MemoryPhi::op_begin() { return OperandTraits
<MemoryPhi>::op_begin(this); } MemoryPhi::const_op_iterator
 MemoryPhi::op_begin() const { return OperandTraits<MemoryPhi
>::op_begin(const_cast<MemoryPhi*>(this)); } MemoryPhi
::op_iterator MemoryPhi::op_end() { return OperandTraits<MemoryPhi
>::op_end(this); } MemoryPhi::const_op_iterator MemoryPhi::
op_end() const { return OperandTraits<MemoryPhi>::op_end
(const_cast<MemoryPhi*>(this)); } MemoryAccess *MemoryPhi
::getOperand(unsigned i_nocapture) const { (static_cast <bool
> (i_nocapture < OperandTraits<MemoryPhi>::operands
(this) && "getOperand() out of range!") ? void (0) : __assert_fail
 ("i_nocapture < OperandTraits<MemoryPhi>::operands(this) && \"getOperand() out of range!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 696, __extension__
 __PRETTY_FUNCTION__)); return cast_or_null<MemoryAccess>
( OperandTraits<MemoryPhi>::op_begin(const_cast<MemoryPhi
*>(this))[i_nocapture].get()); } void MemoryPhi::setOperand
(unsigned i_nocapture, MemoryAccess *Val_nocapture) { (static_cast
 <bool> (i_nocapture < OperandTraits<MemoryPhi>
::operands(this) && "setOperand() out of range!") ? void
 (0) : __assert_fail ("i_nocapture < OperandTraits<MemoryPhi>::operands(this) && \"setOperand() out of range!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 696, __extension__
 __PRETTY_FUNCTION__)); OperandTraits<MemoryPhi>::op_begin
(this)[i_nocapture] = Val_nocapture; } unsigned MemoryPhi::getNumOperands
() const { return OperandTraits<MemoryPhi>::operands(this
); } template <int Idx_nocapture> Use &MemoryPhi::Op
() { return this->OpFrom<Idx_nocapture>(this); } template
 <int Idx_nocapture> const Use &MemoryPhi::Op() const
 { return this->OpFrom<Idx_nocapture>(this); }
697 
698/// Encapsulates MemorySSA, including all data associated with memory
699/// accesses.
700class MemorySSA {
701public:
702  MemorySSA(Function &, AliasAnalysis *, DominatorTree *);
703 
704  // MemorySSA must remain where it's constructed; Walkers it creates store
705  // pointers to it.
706  MemorySSA(MemorySSA &&) = delete;
707 
708  ~MemorySSA();
709 
710  MemorySSAWalker *getWalker();
711  MemorySSAWalker *getSkipSelfWalker();
712 
713  /// Given a memory Mod/Ref'ing instruction, get the MemorySSA
714  /// access associated with it. If passed a basic block gets the memory phi
715  /// node that exists for that block, if there is one. Otherwise, this will get
716  /// a MemoryUseOrDef.
717  MemoryUseOrDef *getMemoryAccess(const Instruction *I) const {
718    return cast_or_null<MemoryUseOrDef>(ValueToMemoryAccess.lookup(I));
719  }
720 
721  MemoryPhi *getMemoryAccess(const BasicBlock *BB) const {
722    return cast_or_null<MemoryPhi>(ValueToMemoryAccess.lookup(cast<Value>(BB)));
23
←
'BB' is a 'CastReturnType'→
24
←
Assuming null pointer is passed into cast→
25
←
Returning null pointer, which participates in a condition later→
723  }
724 
725  DominatorTree &getDomTree() const { return *DT; }
726 
727  void dump() const;
728  void print(raw_ostream &) const;
729 
730  /// Return true if \p MA represents the live on entry value
731  ///
732  /// Loads and stores from pointer arguments and other global values may be
733  /// defined by memory operations that do not occur in the current function, so
734  /// they may be live on entry to the function. MemorySSA represents such
735  /// memory state by the live on entry definition, which is guaranteed to occur
736  /// before any other memory access in the function.
737  inline bool isLiveOnEntryDef(const MemoryAccess *MA) const {
738    return MA == LiveOnEntryDef.get();
739  }
740 
741  inline MemoryAccess *getLiveOnEntryDef() const {
742    return LiveOnEntryDef.get();
743  }
744 
745  // Sadly, iplists, by default, owns and deletes pointers added to the
746  // list. It's not currently possible to have two iplists for the same type,
747  // where one owns the pointers, and one does not. This is because the traits
748  // are per-type, not per-tag.  If this ever changes, we should make the
749  // DefList an iplist.
750  using AccessList = iplist<MemoryAccess, ilist_tag<MSSAHelpers::AllAccessTag>>;
751  using DefsList =
752      simple_ilist<MemoryAccess, ilist_tag<MSSAHelpers::DefsOnlyTag>>;
753 
754  /// Return the list of MemoryAccess's for a given basic block.
755  ///
756  /// This list is not modifiable by the user.
757  const AccessList *getBlockAccesses(const BasicBlock *BB) const {
758    return getWritableBlockAccesses(BB);
6
←
Calling 'MemorySSA::getWritableBlockAccesses'→
10
←
Returning from 'MemorySSA::getWritableBlockAccesses'→
11
←
Returning pointer, which participates in a condition later→
12
←
Returning pointer→
759  }
760 
761  /// Return the list of MemoryDef's and MemoryPhi's for a given basic
762  /// block.
763  ///
764  /// This list is not modifiable by the user.
765  const DefsList *getBlockDefs(const BasicBlock *BB) const {
766    return getWritableBlockDefs(BB);
16
←
Calling 'MemorySSA::getWritableBlockDefs'→
19
←
Returning from 'MemorySSA::getWritableBlockDefs'→
20
←
Returning pointer, which participates in a condition later→
767  }
768 
769  /// Given two memory accesses in the same basic block, determine
770  /// whether MemoryAccess \p A dominates MemoryAccess \p B.
771  bool locallyDominates(const MemoryAccess *A, const MemoryAccess *B) const;
772 
773  /// Given two memory accesses in potentially different blocks,
774  /// determine whether MemoryAccess \p A dominates MemoryAccess \p B.
775  bool dominates(const MemoryAccess *A, const MemoryAccess *B) const;
776 
777  /// Given a MemoryAccess and a Use, determine whether MemoryAccess \p A
778  /// dominates Use \p B.
779  bool dominates(const MemoryAccess *A, const Use &B) const;
780 
781  enum class VerificationLevel { Fast, Full };
782  /// Verify that MemorySSA is self consistent (IE definitions dominate
783  /// all uses, uses appear in the right places).  This is used by unit tests.
784  void verifyMemorySSA(VerificationLevel = VerificationLevel::Fast) const;
785 
786  /// Used in various insertion functions to specify whether we are talking
787  /// about the beginning or end of a block.
788  enum InsertionPlace { Beginning, End, BeforeTerminator };
789 
790  /// By default, uses are *not* optimized during MemorySSA construction.
791  /// Calling this method will attempt to optimize all MemoryUses, if this has
792  /// not happened yet for this MemorySSA instance. This should be done if you
793  /// plan to query the clobbering access for most uses, or if you walk the
794  /// def-use chain of uses.
795  void ensureOptimizedUses();
796 
797  AliasAnalysis &getAA() { return *AA; }
798 
799protected:
800  // Used by Memory SSA dumpers and wrapper pass
801  friend class MemorySSAPrinterLegacyPass;
802  friend class MemorySSAUpdater;
803 
804  void verifyOrderingDominationAndDefUses(
805      Function &F, VerificationLevel = VerificationLevel::Fast) const;
806  void verifyDominationNumbers(const Function &F) const;
807  void verifyPrevDefInPhis(Function &F) const;
808 
809  // This is used by the use optimizer and updater.
810  AccessList *getWritableBlockAccesses(const BasicBlock *BB) const {
811    auto It = PerBlockAccesses.find(BB);
812    return It == PerBlockAccesses.end() ? nullptr : It->second.get();
7
←
'?' condition is false→
8
←
Returning pointer, which participates in a condition later→
9
←
Returning pointer→
813  }
814 
815  // This is used by the use optimizer and updater.
816  DefsList *getWritableBlockDefs(const BasicBlock *BB) const {
817    auto It = PerBlockDefs.find(BB);
818    return It == PerBlockDefs.end() ? nullptr : It->second.get();
17
←
'?' condition is false→
18
←
Returning pointer, which participates in a condition later→
819  }
820 
821  // These is used by the updater to perform various internal MemorySSA
822  // machinsations.  They do not always leave the IR in a correct state, and
823  // relies on the updater to fixup what it breaks, so it is not public.
824 
825  void moveTo(MemoryUseOrDef *What, BasicBlock *BB, AccessList::iterator Where);
826  void moveTo(MemoryAccess *What, BasicBlock *BB, InsertionPlace Point);
827 
828  // Rename the dominator tree branch rooted at BB.
829  void renamePass(BasicBlock *BB, MemoryAccess *IncomingVal,
830                  SmallPtrSetImpl<BasicBlock *> &Visited) {
831    renamePass(DT->getNode(BB), IncomingVal, Visited, true, true);
832  }
833 
834  void removeFromLookups(MemoryAccess *);
835  void removeFromLists(MemoryAccess *, bool ShouldDelete = true);
836  void insertIntoListsForBlock(MemoryAccess *, const BasicBlock *,
837                               InsertionPlace);
838  void insertIntoListsBefore(MemoryAccess *, const BasicBlock *,
839                             AccessList::iterator);
840  MemoryUseOrDef *createDefinedAccess(Instruction *, MemoryAccess *,
841                                      const MemoryUseOrDef *Template = nullptr,
842                                      bool CreationMustSucceed = true);
843 
844private:
845  class ClobberWalkerBase;
846  class CachingWalker;
847  class SkipSelfWalker;
848  class OptimizeUses;
849 
850  CachingWalker *getWalkerImpl();
851  void buildMemorySSA(BatchAAResults &BAA);
852 
853  void prepareForMoveTo(MemoryAccess *, BasicBlock *);
854  void verifyUseInDefs(MemoryAccess *, MemoryAccess *) const;
855 
856  using AccessMap = DenseMap<const BasicBlock *, std::unique_ptr<AccessList>>;
857  using DefsMap = DenseMap<const BasicBlock *, std::unique_ptr<DefsList>>;
858 
859  void markUnreachableAsLiveOnEntry(BasicBlock *BB);
860  MemoryPhi *createMemoryPhi(BasicBlock *BB);
861  template <typename AliasAnalysisType>
862  MemoryUseOrDef *createNewAccess(Instruction *, AliasAnalysisType *,
863                                  const MemoryUseOrDef *Template = nullptr);
864  void placePHINodes(const SmallPtrSetImpl<BasicBlock *> &);
865  MemoryAccess *renameBlock(BasicBlock *, MemoryAccess *, bool);
866  void renameSuccessorPhis(BasicBlock *, MemoryAccess *, bool);
867  void renamePass(DomTreeNode *, MemoryAccess *IncomingVal,
868                  SmallPtrSetImpl<BasicBlock *> &Visited,
869                  bool SkipVisited = false, bool RenameAllUses = false);
870  AccessList *getOrCreateAccessList(const BasicBlock *);
871  DefsList *getOrCreateDefsList(const BasicBlock *);
872  void renumberBlock(const BasicBlock *) const;
873  AliasAnalysis *AA = nullptr;
874  DominatorTree *DT;
875  Function &F;
876 
877  // Memory SSA mappings
878  DenseMap<const Value *, MemoryAccess *> ValueToMemoryAccess;
879 
880  // These two mappings contain the main block to access/def mappings for
881  // MemorySSA. The list contained in PerBlockAccesses really owns all the
882  // MemoryAccesses.
883  // Both maps maintain the invariant that if a block is found in them, the
884  // corresponding list is not empty, and if a block is not found in them, the
885  // corresponding list is empty.
886  AccessMap PerBlockAccesses;
887  DefsMap PerBlockDefs;
888  std::unique_ptr<MemoryAccess, ValueDeleter> LiveOnEntryDef;
889 
890  // Domination mappings
891  // Note that the numbering is local to a block, even though the map is
892  // global.
893  mutable SmallPtrSet<const BasicBlock *, 16> BlockNumberingValid;
894  mutable DenseMap<const MemoryAccess *, unsigned long> BlockNumbering;
895 
896  // Memory SSA building info
897  std::unique_ptr<ClobberWalkerBase> WalkerBase;
898  std::unique_ptr<CachingWalker> Walker;
899  std::unique_ptr<SkipSelfWalker> SkipWalker;
900  unsigned NextID = 0;
901  bool IsOptimized = false;
902};
903 
904/// Enables verification of MemorySSA.
905///
906/// The checks which this flag enables is exensive and disabled by default
907/// unless `EXPENSIVE_CHECKS` is defined.  The flag `-verify-memoryssa` can be
908/// used to selectively enable the verification without re-compilation.
909extern bool VerifyMemorySSA;
910 
911// Internal MemorySSA utils, for use by MemorySSA classes and walkers
912class MemorySSAUtil {
913protected:
914  friend class GVNHoist;
915  friend class MemorySSAWalker;
916 
917  // This function should not be used by new passes.
918  static bool defClobbersUseOrDef(MemoryDef *MD, const MemoryUseOrDef *MU,
919                                  AliasAnalysis &AA);
920};
921 
922// This pass does eager building and then printing of MemorySSA. It is used by
923// the tests to be able to build, dump, and verify Memory SSA.
924class MemorySSAPrinterLegacyPass : public FunctionPass {
925public:
926  MemorySSAPrinterLegacyPass();
927 
928  bool runOnFunction(Function &) override;
929  void getAnalysisUsage(AnalysisUsage &AU) const override;
930 
931  static char ID;
932};
933 
934/// An analysis that produces \c MemorySSA for a function.
935///
936class MemorySSAAnalysis : public AnalysisInfoMixin<MemorySSAAnalysis> {
937  friend AnalysisInfoMixin<MemorySSAAnalysis>;
938 
939  static AnalysisKey Key;
940 
941public:
942  // Wrap MemorySSA result to ensure address stability of internal MemorySSA
943  // pointers after construction.  Use a wrapper class instead of plain
944  // unique_ptr<MemorySSA> to avoid build breakage on MSVC.
945  struct Result {
946    Result(std::unique_ptr<MemorySSA> &&MSSA) : MSSA(std::move(MSSA)) {}
947 
948    MemorySSA &getMSSA() { return *MSSA.get(); }
949 
950    std::unique_ptr<MemorySSA> MSSA;
951 
952    bool invalidate(Function &F, const PreservedAnalyses &PA,
953                    FunctionAnalysisManager::Invalidator &Inv);
954  };
955 
956  Result run(Function &F, FunctionAnalysisManager &AM);
957};
958 
959/// Printer pass for \c MemorySSA.
960class MemorySSAPrinterPass : public PassInfoMixin<MemorySSAPrinterPass> {
961  raw_ostream &OS;
962 
963public:
964  explicit MemorySSAPrinterPass(raw_ostream &OS) : OS(OS) {}
965 
966  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
967};
968 
969/// Printer pass for \c MemorySSA via the walker.
970class MemorySSAWalkerPrinterPass
971    : public PassInfoMixin<MemorySSAWalkerPrinterPass> {
972  raw_ostream &OS;
973 
974public:
975  explicit MemorySSAWalkerPrinterPass(raw_ostream &OS) : OS(OS) {}
976 
977  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
978};
979 
980/// Verifier pass for \c MemorySSA.
981struct MemorySSAVerifierPass : PassInfoMixin<MemorySSAVerifierPass> {
982  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
983};
984 
985/// Legacy analysis pass which computes \c MemorySSA.
986class MemorySSAWrapperPass : public FunctionPass {
987public:
988  MemorySSAWrapperPass();
989 
990  static char ID;
991 
992  bool runOnFunction(Function &) override;
993  void releaseMemory() override;
994  MemorySSA &getMSSA() { return *MSSA; }
995  const MemorySSA &getMSSA() const { return *MSSA; }
996 
997  void getAnalysisUsage(AnalysisUsage &AU) const override;
998 
999  void verifyAnalysis() const override;
1000  void print(raw_ostream &OS, const Module *M = nullptr) const override;
1001 
1002private:
1003  std::unique_ptr<MemorySSA> MSSA;
1004};
1005 
1006/// This is the generic walker interface for walkers of MemorySSA.
1007/// Walkers are used to be able to further disambiguate the def-use chains
1008/// MemorySSA gives you, or otherwise produce better info than MemorySSA gives
1009/// you.
1010/// In particular, while the def-use chains provide basic information, and are
1011/// guaranteed to give, for example, the nearest may-aliasing MemoryDef for a
1012/// MemoryUse as AliasAnalysis considers it, a user mant want better or other
1013/// information. In particular, they may want to use SCEV info to further
1014/// disambiguate memory accesses, or they may want the nearest dominating
1015/// may-aliasing MemoryDef for a call or a store. This API enables a
1016/// standardized interface to getting and using that info.
1017class MemorySSAWalker {
1018public:
1019  MemorySSAWalker(MemorySSA *);
1020  virtual ~MemorySSAWalker() = default;
1021 
1022  using MemoryAccessSet = SmallVector<MemoryAccess *, 8>;
1023 
1024  /// Given a memory Mod/Ref/ModRef'ing instruction, calling this
1025  /// will give you the nearest dominating MemoryAccess that Mod's the location
1026  /// the instruction accesses (by skipping any def which AA can prove does not
1027  /// alias the location(s) accessed by the instruction given).
1028  ///
1029  /// Note that this will return a single access, and it must dominate the
1030  /// Instruction, so if an operand of a MemoryPhi node Mod's the instruction,
1031  /// this will return the MemoryPhi, not the operand. This means that
1032  /// given:
1033  /// if (a) {
1034  ///   1 = MemoryDef(liveOnEntry)
1035  ///   store %a
1036  /// } else {
1037  ///   2 = MemoryDef(liveOnEntry)
1038  ///   store %b
1039  /// }
1040  /// 3 = MemoryPhi(2, 1)
1041  /// MemoryUse(3)
1042  /// load %a
1043  ///
1044  /// calling this API on load(%a) will return the MemoryPhi, not the MemoryDef
1045  /// in the if (a) branch.
1046  MemoryAccess *getClobberingMemoryAccess(const Instruction *I,
1047                                          BatchAAResults &AA) {
1048    MemoryAccess *MA = MSSA->getMemoryAccess(I);
1049    assert(MA && "Handed an instruction that MemorySSA doesn't recognize?")(static_cast <bool> (MA && "Handed an instruction that MemorySSA doesn't recognize?"
) ? void (0) : __assert_fail ("MA && \"Handed an instruction that MemorySSA doesn't recognize?\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1049, __extension__
 __PRETTY_FUNCTION__));
1050    return getClobberingMemoryAccess(MA, AA);
1051  }
1052 
1053  /// Does the same thing as getClobberingMemoryAccess(const Instruction *I),
1054  /// but takes a MemoryAccess instead of an Instruction.
1055  virtual MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
1056                                                  BatchAAResults &AA) = 0;
1057 
1058  /// Given a potentially clobbering memory access and a new location,
1059  /// calling this will give you the nearest dominating clobbering MemoryAccess
1060  /// (by skipping non-aliasing def links).
1061  ///
1062  /// This version of the function is mainly used to disambiguate phi translated
1063  /// pointers, where the value of a pointer may have changed from the initial
1064  /// memory access. Note that this expects to be handed either a MemoryUse,
1065  /// or an already potentially clobbering access. Unlike the above API, if
1066  /// given a MemoryDef that clobbers the pointer as the starting access, it
1067  /// will return that MemoryDef, whereas the above would return the clobber
1068  /// starting from the use side of  the memory def.
1069  virtual MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
1070                                                  const MemoryLocation &,
1071                                                  BatchAAResults &AA) = 0;
1072 
1073  MemoryAccess *getClobberingMemoryAccess(const Instruction *I) {
1074    BatchAAResults BAA(MSSA->getAA());
1075    return getClobberingMemoryAccess(I, BAA);
1076  }
1077 
1078  MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA) {
1079    BatchAAResults BAA(MSSA->getAA());
1080    return getClobberingMemoryAccess(MA, BAA);
1081  }
1082 
1083  MemoryAccess *getClobberingMemoryAccess(MemoryAccess *MA,
1084                                          const MemoryLocation &Loc) {
1085    BatchAAResults BAA(MSSA->getAA());
1086    return getClobberingMemoryAccess(MA, Loc, BAA);
1087  }
1088 
1089  /// Given a memory access, invalidate anything this walker knows about
1090  /// that access.
1091  /// This API is used by walkers that store information to perform basic cache
1092  /// invalidation.  This will be called by MemorySSA at appropriate times for
1093  /// the walker it uses or returns.
1094  virtual void invalidateInfo(MemoryAccess *) {}
1095 
1096protected:
1097  friend class MemorySSA; // For updating MSSA pointer in MemorySSA move
1098                          // constructor.
1099  MemorySSA *MSSA;
1100};
1101 
1102/// A MemorySSAWalker that does no alias queries, or anything else. It
1103/// simply returns the links as they were constructed by the builder.
1104class DoNothingMemorySSAWalker final : public MemorySSAWalker {
1105public:
1106  // Keep the overrides below from hiding the Instruction overload of
1107  // getClobberingMemoryAccess.
1108  using MemorySSAWalker::getClobberingMemoryAccess;
1109 
1110  MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
1111                                          BatchAAResults &) override;
1112  MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
1113                                          const MemoryLocation &,
1114                                          BatchAAResults &) override;
1115};
1116 
1117using MemoryAccessPair = std::pair<MemoryAccess *, MemoryLocation>;
1118using ConstMemoryAccessPair = std::pair<const MemoryAccess *, MemoryLocation>;
1119 
1120/// Iterator base class used to implement const and non-const iterators
1121/// over the defining accesses of a MemoryAccess.
1122template <class T>
1123class memoryaccess_def_iterator_base
1124    : public iterator_facade_base<memoryaccess_def_iterator_base<T>,
1125                                  std::forward_iterator_tag, T, ptrdiff_t, T *,
1126                                  T *> {
1127  using BaseT = typename memoryaccess_def_iterator_base::iterator_facade_base;
1128 
1129public:
1130  memoryaccess_def_iterator_base(T *Start) : Access(Start) {}
1131  memoryaccess_def_iterator_base() = default;
1132 
1133  bool operator==(const memoryaccess_def_iterator_base &Other) const {
1134    return Access == Other.Access && (!Access || ArgNo == Other.ArgNo);
1135  }
1136 
1137  // This is a bit ugly, but for MemoryPHI's, unlike PHINodes, you can't get the
1138  // block from the operand in constant time (In a PHINode, the uselist has
1139  // both, so it's just subtraction). We provide it as part of the
1140  // iterator to avoid callers having to linear walk to get the block.
1141  // If the operation becomes constant time on MemoryPHI's, this bit of
1142  // abstraction breaking should be removed.
1143  BasicBlock *getPhiArgBlock() const {
1144    MemoryPhi *MP = dyn_cast<MemoryPhi>(Access);
1145    assert(MP && "Tried to get phi arg block when not iterating over a PHI")(static_cast <bool> (MP && "Tried to get phi arg block when not iterating over a PHI"
) ? void (0) : __assert_fail ("MP && \"Tried to get phi arg block when not iterating over a PHI\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1145, __extension__
 __PRETTY_FUNCTION__));
1146    return MP->getIncomingBlock(ArgNo);
1147  }
1148 
1149  typename std::iterator_traits<BaseT>::pointer operator*() const {
1150    assert(Access && "Tried to access past the end of our iterator")(static_cast <bool> (Access && "Tried to access past the end of our iterator"
) ? void (0) : __assert_fail ("Access && \"Tried to access past the end of our iterator\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1150, __extension__
 __PRETTY_FUNCTION__));
1151    // Go to the first argument for phis, and the defining access for everything
1152    // else.
1153    if (const MemoryPhi *MP = dyn_cast<MemoryPhi>(Access))
1154      return MP->getIncomingValue(ArgNo);
1155    return cast<MemoryUseOrDef>(Access)->getDefiningAccess();
1156  }
1157 
1158  using BaseT::operator++;
1159  memoryaccess_def_iterator_base &operator++() {
1160    assert(Access && "Hit end of iterator")(static_cast <bool> (Access && "Hit end of iterator"
) ? void (0) : __assert_fail ("Access && \"Hit end of iterator\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1160, __extension__
 __PRETTY_FUNCTION__));
1161    if (const MemoryPhi *MP = dyn_cast<MemoryPhi>(Access)) {
1162      if (++ArgNo >= MP->getNumIncomingValues()) {
1163        ArgNo = 0;
1164        Access = nullptr;
1165      }
1166    } else {
1167      Access = nullptr;
1168    }
1169    return *this;
1170  }
1171 
1172private:
1173  T *Access = nullptr;
1174  unsigned ArgNo = 0;
1175};
1176 
1177inline memoryaccess_def_iterator MemoryAccess::defs_begin() {
1178  return memoryaccess_def_iterator(this);
1179}
1180 
1181inline const_memoryaccess_def_iterator MemoryAccess::defs_begin() const {
1182  return const_memoryaccess_def_iterator(this);
1183}
1184 
1185inline memoryaccess_def_iterator MemoryAccess::defs_end() {
1186  return memoryaccess_def_iterator();
1187}
1188 
1189inline const_memoryaccess_def_iterator MemoryAccess::defs_end() const {
1190  return const_memoryaccess_def_iterator();
1191}
1192 
1193/// GraphTraits for a MemoryAccess, which walks defs in the normal case,
1194/// and uses in the inverse case.
1195template <> struct GraphTraits<MemoryAccess *> {
1196  using NodeRef = MemoryAccess *;
1197  using ChildIteratorType = memoryaccess_def_iterator;
1198 
1199  static NodeRef getEntryNode(NodeRef N) { return N; }
1200  static ChildIteratorType child_begin(NodeRef N) { return N->defs_begin(); }
1201  static ChildIteratorType child_end(NodeRef N) { return N->defs_end(); }
1202};
1203 
1204template <> struct GraphTraits<Inverse<MemoryAccess *>> {
1205  using NodeRef = MemoryAccess *;
1206  using ChildIteratorType = MemoryAccess::iterator;
1207 
1208  static NodeRef getEntryNode(NodeRef N) { return N; }
1209  static ChildIteratorType child_begin(NodeRef N) { return N->user_begin(); }
1210  static ChildIteratorType child_end(NodeRef N) { return N->user_end(); }
1211};
1212 
1213/// Provide an iterator that walks defs, giving both the memory access,
1214/// and the current pointer location, updating the pointer location as it
1215/// changes due to phi node translation.
1216///
1217/// This iterator, while somewhat specialized, is what most clients actually
1218/// want when walking upwards through MemorySSA def chains. It takes a pair of
1219/// <MemoryAccess,MemoryLocation>, and walks defs, properly translating the
1220/// memory location through phi nodes for the user.
1221class upward_defs_iterator
1222    : public iterator_facade_base<upward_defs_iterator,
1223                                  std::forward_iterator_tag,
1224                                  const MemoryAccessPair> {
1225  using BaseT = upward_defs_iterator::iterator_facade_base;
1226 
1227public:
1228  upward_defs_iterator(const MemoryAccessPair &Info, DominatorTree *DT)
1229      : DefIterator(Info.first), Location(Info.second),
1230        OriginalAccess(Info.first), DT(DT) {
1231    CurrentPair.first = nullptr;
1232 
1233    WalkingPhi = Info.first && isa<MemoryPhi>(Info.first);
1234    fillInCurrentPair();
1235  }
1236 
1237  upward_defs_iterator() { CurrentPair.first = nullptr; }
1238 
1239  bool operator==(const upward_defs_iterator &Other) const {
1240    return DefIterator == Other.DefIterator;
1241  }
1242 
1243  typename std::iterator_traits<BaseT>::reference operator*() const {
1244    assert(DefIterator != OriginalAccess->defs_end() &&(static_cast <bool> (DefIterator != OriginalAccess->
defs_end() && "Tried to access past the end of our iterator"
) ? void (0) : __assert_fail ("DefIterator != OriginalAccess->defs_end() && \"Tried to access past the end of our iterator\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1245, __extension__
 __PRETTY_FUNCTION__))
1245           "Tried to access past the end of our iterator")(static_cast <bool> (DefIterator != OriginalAccess->
defs_end() && "Tried to access past the end of our iterator"
) ? void (0) : __assert_fail ("DefIterator != OriginalAccess->defs_end() && \"Tried to access past the end of our iterator\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1245, __extension__
 __PRETTY_FUNCTION__));
1246    return CurrentPair;
1247  }
1248 
1249  using BaseT::operator++;
1250  upward_defs_iterator &operator++() {
1251    assert(DefIterator != OriginalAccess->defs_end() &&(static_cast <bool> (DefIterator != OriginalAccess->
defs_end() && "Tried to access past the end of the iterator"
) ? void (0) : __assert_fail ("DefIterator != OriginalAccess->defs_end() && \"Tried to access past the end of the iterator\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1252, __extension__
 __PRETTY_FUNCTION__))
1252           "Tried to access past the end of the iterator")(static_cast <bool> (DefIterator != OriginalAccess->
defs_end() && "Tried to access past the end of the iterator"
) ? void (0) : __assert_fail ("DefIterator != OriginalAccess->defs_end() && \"Tried to access past the end of the iterator\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1252, __extension__
 __PRETTY_FUNCTION__));
1253    ++DefIterator;
1254    if (DefIterator != OriginalAccess->defs_end())
1255      fillInCurrentPair();
1256    return *this;
1257  }
1258 
1259  BasicBlock *getPhiArgBlock() const { return DefIterator.getPhiArgBlock(); }
1260 
1261private:
1262  /// Returns true if \p Ptr is guaranteed to be loop invariant for any possible
1263  /// loop. In particular, this guarantees that it only references a single
1264  /// MemoryLocation during execution of the containing function.
1265  bool IsGuaranteedLoopInvariant(const Value *Ptr) const;
1266 
1267  void fillInCurrentPair() {
1268    CurrentPair.first = *DefIterator;
1269    CurrentPair.second = Location;
1270    if (WalkingPhi && Location.Ptr) {
1271      PHITransAddr Translator(
1272          const_cast<Value *>(Location.Ptr),
1273          OriginalAccess->getBlock()->getModule()->getDataLayout(), nullptr);
1274 
1275      if (Value *Addr =
1276              Translator.translateValue(OriginalAccess->getBlock(),
1277                                        DefIterator.getPhiArgBlock(), DT, true))
1278        if (Addr != CurrentPair.second.Ptr)
1279          CurrentPair.second = CurrentPair.second.getWithNewPtr(Addr);
1280 
1281      // Mark size as unknown, if the location is not guaranteed to be
1282      // loop-invariant for any possible loop in the function. Setting the size
1283      // to unknown guarantees that any memory accesses that access locations
1284      // after the pointer are considered as clobbers, which is important to
1285      // catch loop carried dependences.
1286      if (!IsGuaranteedLoopInvariant(CurrentPair.second.Ptr))
1287        CurrentPair.second = CurrentPair.second.getWithNewSize(
1288            LocationSize::beforeOrAfterPointer());
1289    }
1290  }
1291 
1292  MemoryAccessPair CurrentPair;
1293  memoryaccess_def_iterator DefIterator;
1294  MemoryLocation Location;
1295  MemoryAccess *OriginalAccess = nullptr;
1296  DominatorTree *DT = nullptr;
1297  bool WalkingPhi = false;
1298};
1299 
1300inline upward_defs_iterator
1301upward_defs_begin(const MemoryAccessPair &Pair, DominatorTree &DT) {
1302  return upward_defs_iterator(Pair, &DT);
1303}
1304 
1305inline upward_defs_iterator upward_defs_end() { return upward_defs_iterator(); }
1306 
1307inline iterator_range<upward_defs_iterator>
1308upward_defs(const MemoryAccessPair &Pair, DominatorTree &DT) {
1309  return make_range(upward_defs_begin(Pair, DT), upward_defs_end());
1310}
1311 
1312/// Walks the defining accesses of MemoryDefs. Stops after we hit something that
1313/// has no defining use (e.g. a MemoryPhi or liveOnEntry). Note that, when
1314/// comparing against a null def_chain_iterator, this will compare equal only
1315/// after walking said Phi/liveOnEntry.
1316///
1317/// The UseOptimizedChain flag specifies whether to walk the clobbering
1318/// access chain, or all the accesses.
1319///
1320/// Normally, MemoryDef are all just def/use linked together, so a def_chain on
1321/// a MemoryDef will walk all MemoryDefs above it in the program until it hits
1322/// a phi node.  The optimized chain walks the clobbering access of a store.
1323/// So if you are just trying to find, given a store, what the next
1324/// thing that would clobber the same memory is, you want the optimized chain.
1325template <class T, bool UseOptimizedChain = false>
1326struct def_chain_iterator
1327    : public iterator_facade_base<def_chain_iterator<T, UseOptimizedChain>,
1328                                  std::forward_iterator_tag, MemoryAccess *> {
1329  def_chain_iterator() : MA(nullptr) {}
1330  def_chain_iterator(T MA) : MA(MA) {}
1331 
1332  T operator*() const { return MA; }
1333 
1334  def_chain_iterator &operator++() {
1335    // N.B. liveOnEntry has a null defining access.
1336    if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA)) {
1337      if (UseOptimizedChain && MUD->isOptimized())
1338        MA = MUD->getOptimized();
1339      else
1340        MA = MUD->getDefiningAccess();
1341    } else {
1342      MA = nullptr;
1343    }
1344 
1345    return *this;
1346  }
1347 
1348  bool operator==(const def_chain_iterator &O) const { return MA == O.MA; }
1349 
1350private:
1351  T MA;
1352};
1353 
1354template <class T>
1355inline iterator_range<def_chain_iterator<T>>
1356def_chain(T MA, MemoryAccess *UpTo = nullptr) {
1357#ifdef EXPENSIVE_CHECKS
1358  assert((!UpTo || find(def_chain(MA), UpTo) != def_chain_iterator<T>()) &&(static_cast <bool> ((!UpTo || find(def_chain(MA), UpTo
) != def_chain_iterator<T>()) && "UpTo isn't in the def chain!"
) ? void (0) : __assert_fail ("(!UpTo || find(def_chain(MA), UpTo) != def_chain_iterator<T>()) && \"UpTo isn't in the def chain!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1359, __extension__
 __PRETTY_FUNCTION__))
1359         "UpTo isn't in the def chain!")(static_cast <bool> ((!UpTo || find(def_chain(MA), UpTo
) != def_chain_iterator<T>()) && "UpTo isn't in the def chain!"
) ? void (0) : __assert_fail ("(!UpTo || find(def_chain(MA), UpTo) != def_chain_iterator<T>()) && \"UpTo isn't in the def chain!\""
, "llvm/include/llvm/Analysis/MemorySSA.h", 1359, __extension__
 __PRETTY_FUNCTION__));
1360#endif
1361  return make_range(def_chain_iterator<T>(MA), def_chain_iterator<T>(UpTo));
1362}
1363 
1364template <class T>
1365inline iterator_range<def_chain_iterator<T, true>> optimized_def_chain(T MA) {
1366  return make_range(def_chain_iterator<T, true>(MA),
1367                    def_chain_iterator<T, true>(nullptr));
1368}
1369 
1370} // end namespace llvm
1371 
1372#endif // LLVM_ANALYSIS_MEMORYSSA_H