/build/source/llvm/lib/CodeGen/CodeGenPrepare.cpp

Bug Summary

File:	build/source/llvm/lib/CodeGen/CodeGenPrepare.cpp
Warning:	line 1242, column 37 Called C++ object pointer is null
Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name CodeGenPrepare.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/CodeGen -I /build/source/llvm/lib/CodeGen -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/CodeGen/CodeGenPrepare.cpp
1//===- CodeGenPrepare.cpp - Prepare a function for code generation --------===//
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 pass munges the code in the input function to better prepare it for
10// SelectionDAG-based code generation. This works around limitations in it's
11// basic-block-at-a-time approach. It should eventually be removed.
12//
13//===----------------------------------------------------------------------===//

15#include "llvm/ADT/APInt.h"
16#include "llvm/ADT/ArrayRef.h"
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/MapVector.h"
19#include "llvm/ADT/PointerIntPair.h"
20#include "llvm/ADT/STLExtras.h"
21#include "llvm/ADT/SmallPtrSet.h"
22#include "llvm/ADT/SmallVector.h"
23#include "llvm/ADT/Statistic.h"
24#include "llvm/Analysis/BlockFrequencyInfo.h"
25#include "llvm/Analysis/BranchProbabilityInfo.h"
26#include "llvm/Analysis/InstructionSimplify.h"
27#include "llvm/Analysis/LoopInfo.h"
28#include "llvm/Analysis/ProfileSummaryInfo.h"
29#include "llvm/Analysis/TargetLibraryInfo.h"
30#include "llvm/Analysis/TargetTransformInfo.h"
31#include "llvm/Analysis/ValueTracking.h"
32#include "llvm/Analysis/VectorUtils.h"
33#include "llvm/CodeGen/Analysis.h"
34#include "llvm/CodeGen/BasicBlockSectionsProfileReader.h"
35#include "llvm/CodeGen/ISDOpcodes.h"
36#include "llvm/CodeGen/MachineValueType.h"
37#include "llvm/CodeGen/SelectionDAGNodes.h"
38#include "llvm/CodeGen/TargetLowering.h"
39#include "llvm/CodeGen/TargetPassConfig.h"
40#include "llvm/CodeGen/TargetSubtargetInfo.h"
41#include "llvm/CodeGen/ValueTypes.h"
42#include "llvm/Config/llvm-config.h"
43#include "llvm/IR/Argument.h"
44#include "llvm/IR/Attributes.h"
45#include "llvm/IR/BasicBlock.h"
46#include "llvm/IR/Constant.h"
47#include "llvm/IR/Constants.h"
48#include "llvm/IR/DataLayout.h"
49#include "llvm/IR/DebugInfo.h"
50#include "llvm/IR/DerivedTypes.h"
51#include "llvm/IR/Dominators.h"
52#include "llvm/IR/Function.h"
53#include "llvm/IR/GetElementPtrTypeIterator.h"
54#include "llvm/IR/GlobalValue.h"
55#include "llvm/IR/GlobalVariable.h"
56#include "llvm/IR/IRBuilder.h"
57#include "llvm/IR/InlineAsm.h"
58#include "llvm/IR/InstrTypes.h"
59#include "llvm/IR/Instruction.h"
60#include "llvm/IR/Instructions.h"
61#include "llvm/IR/IntrinsicInst.h"
62#include "llvm/IR/Intrinsics.h"
63#include "llvm/IR/IntrinsicsAArch64.h"
64#include "llvm/IR/LLVMContext.h"
65#include "llvm/IR/MDBuilder.h"
66#include "llvm/IR/Module.h"
67#include "llvm/IR/Operator.h"
68#include "llvm/IR/PatternMatch.h"
69#include "llvm/IR/ProfDataUtils.h"
70#include "llvm/IR/Statepoint.h"
71#include "llvm/IR/Type.h"
72#include "llvm/IR/Use.h"
73#include "llvm/IR/User.h"
74#include "llvm/IR/Value.h"
75#include "llvm/IR/ValueHandle.h"
76#include "llvm/IR/ValueMap.h"
77#include "llvm/InitializePasses.h"
78#include "llvm/Pass.h"
79#include "llvm/Support/BlockFrequency.h"
80#include "llvm/Support/BranchProbability.h"
81#include "llvm/Support/Casting.h"
82#include "llvm/Support/CommandLine.h"
83#include "llvm/Support/Compiler.h"
84#include "llvm/Support/Debug.h"
85#include "llvm/Support/ErrorHandling.h"
86#include "llvm/Support/MathExtras.h"
87#include "llvm/Support/raw_ostream.h"
88#include "llvm/Target/TargetMachine.h"
89#include "llvm/Target/TargetOptions.h"
90#include "llvm/Transforms/Utils/BasicBlockUtils.h"
91#include "llvm/Transforms/Utils/BypassSlowDivision.h"
92#include "llvm/Transforms/Utils/Local.h"
93#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
94#include "llvm/Transforms/Utils/SizeOpts.h"
95#include <algorithm>
96#include <cassert>
97#include <cstdint>
98#include <iterator>
99#include <limits>
100#include <memory>
101#include <optional>
102#include <utility>
103#include <vector>

105using namespace llvm;
106using namespace llvm::PatternMatch;

108#define DEBUG_TYPE"codegenprepare" "codegenprepare"

110STATISTIC(NumBlocksElim, "Number of blocks eliminated")static llvm::Statistic NumBlocksElim = {"codegenprepare", "NumBlocksElim"
, "Number of blocks eliminated"};
111STATISTIC(NumPHIsElim, "Number of trivial PHIs eliminated")static llvm::Statistic NumPHIsElim = {"codegenprepare", "NumPHIsElim"
, "Number of trivial PHIs eliminated"};
112STATISTIC(NumGEPsElim, "Number of GEPs converted to casts")static llvm::Statistic NumGEPsElim = {"codegenprepare", "NumGEPsElim"
, "Number of GEPs converted to casts"};
113STATISTIC(NumCmpUses, "Number of uses of Cmp expressions replaced with uses of "static llvm::Statistic NumCmpUses = {"codegenprepare", "NumCmpUses"
, "Number of uses of Cmp expressions replaced with uses of " "sunken Cmps"
}
                    "sunken Cmps")static llvm::Statistic NumCmpUses = {"codegenprepare", "NumCmpUses"
, "Number of uses of Cmp expressions replaced with uses of " "sunken Cmps"
};
115STATISTIC(NumCastUses, "Number of uses of Cast expressions replaced with uses "static llvm::Statistic NumCastUses = {"codegenprepare", "NumCastUses"
, "Number of uses of Cast expressions replaced with uses " "of sunken Casts"
}
                     "of sunken Casts")static llvm::Statistic NumCastUses = {"codegenprepare", "NumCastUses"
, "Number of uses of Cast expressions replaced with uses " "of sunken Casts"
};
117STATISTIC(NumMemoryInsts, "Number of memory instructions whose address "static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts"
, "Number of memory instructions whose address " "computations were sunk"
}
                        "computations were sunk")static llvm::Statistic NumMemoryInsts = {"codegenprepare", "NumMemoryInsts"
, "Number of memory instructions whose address " "computations were sunk"
};
119STATISTIC(NumMemoryInstsPhiCreated,static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
 "computations were sunk to memory instructions"}
        "Number of phis created when address "static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
 "computations were sunk to memory instructions"}
        "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsPhiCreated = {"codegenprepare"
, "NumMemoryInstsPhiCreated", "Number of phis created when address "
 "computations were sunk to memory instructions"};
122STATISTIC(NumMemoryInstsSelectCreated,static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
 "computations were sunk to memory instructions"}
        "Number of select created when address "static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
 "computations were sunk to memory instructions"}
        "computations were sunk to memory instructions")static llvm::Statistic NumMemoryInstsSelectCreated = {"codegenprepare"
, "NumMemoryInstsSelectCreated", "Number of select created when address "
 "computations were sunk to memory instructions"};
125STATISTIC(NumExtsMoved, "Number of [s|z]ext instructions combined with loads")static llvm::Statistic NumExtsMoved = {"codegenprepare", "NumExtsMoved"
, "Number of [s|z]ext instructions combined with loads"};
126STATISTIC(NumExtUses, "Number of uses of [s|z]ext instructions optimized")static llvm::Statistic NumExtUses = {"codegenprepare", "NumExtUses"
, "Number of uses of [s|z]ext instructions optimized"};
127STATISTIC(NumAndsAdded,static llvm::Statistic NumAndsAdded = {"codegenprepare", "NumAndsAdded"
, "Number of and mask instructions added to form ext loads"}
        "Number of and mask instructions added to form ext loads")static llvm::Statistic NumAndsAdded = {"codegenprepare", "NumAndsAdded"
, "Number of and mask instructions added to form ext loads"};
129STATISTIC(NumAndUses, "Number of uses of and mask instructions optimized")static llvm::Statistic NumAndUses = {"codegenprepare", "NumAndUses"
, "Number of uses of and mask instructions optimized"};
130STATISTIC(NumRetsDup, "Number of return instructions duplicated")static llvm::Statistic NumRetsDup = {"codegenprepare", "NumRetsDup"
, "Number of return instructions duplicated"};
131STATISTIC(NumDbgValueMoved, "Number of debug value instructions moved")static llvm::Statistic NumDbgValueMoved = {"codegenprepare", "NumDbgValueMoved"
, "Number of debug value instructions moved"};
132STATISTIC(NumSelectsExpanded, "Number of selects turned into branches")static llvm::Statistic NumSelectsExpanded = {"codegenprepare"
, "NumSelectsExpanded", "Number of selects turned into branches"
};
133STATISTIC(NumStoreExtractExposed, "Number of store(extractelement) exposed")static llvm::Statistic NumStoreExtractExposed = {"codegenprepare"
, "NumStoreExtractExposed", "Number of store(extractelement) exposed"
};

135static cl::opt<bool> DisableBranchOpts(
  "disable-cgp-branch-opts", cl::Hidden, cl::init(false),
  cl::desc("Disable branch optimizations in CodeGenPrepare"));

139static cl::opt<bool>
  DisableGCOpts("disable-cgp-gc-opts", cl::Hidden, cl::init(false),
                cl::desc("Disable GC optimizations in CodeGenPrepare"));

143static cl::opt<bool>
  DisableSelectToBranch("disable-cgp-select2branch", cl::Hidden,
                        cl::init(false),
                        cl::desc("Disable select to branch conversion."));

148static cl::opt<bool>
  AddrSinkUsingGEPs("addr-sink-using-gep", cl::Hidden, cl::init(true),
                    cl::desc("Address sinking in CGP using GEPs."));

152static cl::opt<bool>
  EnableAndCmpSinking("enable-andcmp-sinking", cl::Hidden, cl::init(true),
                      cl::desc("Enable sinkinig and/cmp into branches."));

156static cl::opt<bool> DisableStoreExtract(
  "disable-cgp-store-extract", cl::Hidden, cl::init(false),
  cl::desc("Disable store(extract) optimizations in CodeGenPrepare"));

160static cl::opt<bool> StressStoreExtract(
  "stress-cgp-store-extract", cl::Hidden, cl::init(false),
  cl::desc("Stress test store(extract) optimizations in CodeGenPrepare"));

164static cl::opt<bool> DisableExtLdPromotion(
  "disable-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
  cl::desc("Disable ext(promotable(ld)) -> promoted(ext(ld)) optimization in "
           "CodeGenPrepare"));

169static cl::opt<bool> StressExtLdPromotion(
  "stress-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
  cl::desc("Stress test ext(promotable(ld)) -> promoted(ext(ld)) "
           "optimization in CodeGenPrepare"));

174static cl::opt<bool> DisablePreheaderProtect(
  "disable-preheader-prot", cl::Hidden, cl::init(false),
  cl::desc("Disable protection against removing loop preheaders"));

178static cl::opt<bool> ProfileGuidedSectionPrefix(
  "profile-guided-section-prefix", cl::Hidden, cl::init(true),
  cl::desc("Use profile info to add section prefix for hot/cold functions"));

182static cl::opt<bool> ProfileUnknownInSpecialSection(
  "profile-unknown-in-special-section", cl::Hidden,
  cl::desc("In profiling mode like sampleFDO, if a function doesn't have "
           "profile, we cannot tell the function is cold for sure because "
           "it may be a function newly added without ever being sampled. "
           "With the flag enabled, compiler can put such profile unknown "
           "functions into a special section, so runtime system can choose "
           "to handle it in a different way than .text section, to save "
           "RAM for example. "));

192static cl::opt<bool> BBSectionsGuidedSectionPrefix(
  "bbsections-guided-section-prefix", cl::Hidden, cl::init(true),
  cl::desc("Use the basic-block-sections profile to determine the text "
           "section prefix for hot functions. Functions with "
           "basic-block-sections profile will be placed in `.text.hot` "
           "regardless of their FDO profile info. Other functions won't be "
           "impacted, i.e., their prefixes will be decided by FDO/sampleFDO "
           "profiles."));

201static cl::opt<unsigned> FreqRatioToSkipMerge(
  "cgp-freq-ratio-to-skip-merge", cl::Hidden, cl::init(2),
  cl::desc("Skip merging empty blocks if (frequency of empty block) / "
           "(frequency of destination block) is greater than this ratio"));

206static cl::opt<bool> ForceSplitStore(
  "force-split-store", cl::Hidden, cl::init(false),
  cl::desc("Force store splitting no matter what the target query says."));

210static cl::opt<bool> EnableTypePromotionMerge(
  "cgp-type-promotion-merge", cl::Hidden,
  cl::desc("Enable merging of redundant sexts when one is dominating"
           " the other."),
  cl::init(true));

216static cl::opt<bool> DisableComplexAddrModes(
  "disable-complex-addr-modes", cl::Hidden, cl::init(false),
  cl::desc("Disables combining addressing modes with different parts "
           "in optimizeMemoryInst."));

221static cl::opt<bool>
  AddrSinkNewPhis("addr-sink-new-phis", cl::Hidden, cl::init(false),
                  cl::desc("Allow creation of Phis in Address sinking."));

225static cl::opt<bool> AddrSinkNewSelects(
  "addr-sink-new-select", cl::Hidden, cl::init(true),
  cl::desc("Allow creation of selects in Address sinking."));

229static cl::opt<bool> AddrSinkCombineBaseReg(
  "addr-sink-combine-base-reg", cl::Hidden, cl::init(true),
  cl::desc("Allow combining of BaseReg field in Address sinking."));

233static cl::opt<bool> AddrSinkCombineBaseGV(
  "addr-sink-combine-base-gv", cl::Hidden, cl::init(true),
  cl::desc("Allow combining of BaseGV field in Address sinking."));

237static cl::opt<bool> AddrSinkCombineBaseOffs(
  "addr-sink-combine-base-offs", cl::Hidden, cl::init(true),
  cl::desc("Allow combining of BaseOffs field in Address sinking."));

241static cl::opt<bool> AddrSinkCombineScaledReg(
  "addr-sink-combine-scaled-reg", cl::Hidden, cl::init(true),
  cl::desc("Allow combining of ScaledReg field in Address sinking."));

245static cl::opt<bool>
  EnableGEPOffsetSplit("cgp-split-large-offset-gep", cl::Hidden,
                       cl::init(true),
                       cl::desc("Enable splitting large offset of GEP."));

250static cl::opt<bool> EnableICMP_EQToICMP_ST(
  "cgp-icmp-eq2icmp-st", cl::Hidden, cl::init(false),
  cl::desc("Enable ICMP_EQ to ICMP_S(L|G)T conversion."));

254static cl::opt<bool>
  VerifyBFIUpdates("cgp-verify-bfi-updates", cl::Hidden, cl::init(false),
                   cl::desc("Enable BFI update verification for "
                            "CodeGenPrepare."));

259static cl::opt<bool>
  OptimizePhiTypes("cgp-optimize-phi-types", cl::Hidden, cl::init(false),
                   cl::desc("Enable converting phi types in CodeGenPrepare"));

263static cl::opt<unsigned>
  HugeFuncThresholdInCGPP("cgpp-huge-func", cl::init(10000), cl::Hidden,
                          cl::desc("Least BB number of huge function."));

267static cl::opt<unsigned>
  MaxAddressUsersToScan("cgp-max-address-users-to-scan", cl::init(100),
                        cl::Hidden,
                        cl::desc("Max number of address users to look at"));
271namespace {

273enum ExtType {
ZeroExtension, // Zero extension has been seen.
SignExtension, // Sign extension has been seen.
BothExtension  // This extension type is used if we saw sext after
               // ZeroExtension had been set, or if we saw zext after
               // SignExtension had been set. It makes the type
               // information of a promoted instruction invalid.
280};

282enum ModifyDT {
NotModifyDT, // Not Modify any DT.
ModifyBBDT,  // Modify the Basic Block Dominator Tree.
ModifyInstDT // Modify the Instruction Dominator in a Basic Block,
             // This usually means we move/delete/insert instruction
             // in a Basic Block. So we should re-iterate instructions
             // in such Basic Block.
289};

291using SetOfInstrs = SmallPtrSet<Instruction *, 16>;
292using TypeIsSExt = PointerIntPair<Type *, 2, ExtType>;
293using InstrToOrigTy = DenseMap<Instruction *, TypeIsSExt>;
294using SExts = SmallVector<Instruction *, 16>;
295using ValueToSExts = MapVector<Value *, SExts>;

297class TypePromotionTransaction;

299class CodeGenPrepare : public FunctionPass {
const TargetMachine *TM = nullptr;
const TargetSubtargetInfo *SubtargetInfo = nullptr;
const TargetLowering *TLI = nullptr;
const TargetRegisterInfo *TRI = nullptr;
const TargetTransformInfo *TTI = nullptr;
const BasicBlockSectionsProfileReader *BBSectionsProfileReader = nullptr;
const TargetLibraryInfo *TLInfo = nullptr;
const LoopInfo *LI = nullptr;
std::unique_ptr<BlockFrequencyInfo> BFI;
std::unique_ptr<BranchProbabilityInfo> BPI;
ProfileSummaryInfo *PSI = nullptr;

/// As we scan instructions optimizing them, this is the next instruction
/// to optimize. Transforms that can invalidate this should update it.
BasicBlock::iterator CurInstIterator;

/// Keeps track of non-local addresses that have been sunk into a block.
/// This allows us to avoid inserting duplicate code for blocks with
/// multiple load/stores of the same address. The usage of WeakTrackingVH
/// enables SunkAddrs to be treated as a cache whose entries can be
/// invalidated if a sunken address computation has been erased.
ValueMap<Value *, WeakTrackingVH> SunkAddrs;

/// Keeps track of all instructions inserted for the current function.
SetOfInstrs InsertedInsts;

/// Keeps track of the type of the related instruction before their
/// promotion for the current function.
InstrToOrigTy PromotedInsts;

/// Keep track of instructions removed during promotion.
SetOfInstrs RemovedInsts;

/// Keep track of sext chains based on their initial value.
DenseMap<Value *, Instruction *> SeenChainsForSExt;

/// Keep track of GEPs accessing the same data structures such as structs or
/// arrays that are candidates to be split later because of their large
/// size.
MapVector<AssertingVH<Value>,
          SmallVector<std::pair<AssertingVH<GetElementPtrInst>, int64_t>, 32>>
    LargeOffsetGEPMap;

/// Keep track of new GEP base after splitting the GEPs having large offset.
SmallSet<AssertingVH<Value>, 2> NewGEPBases;

/// Map serial numbers to Large offset GEPs.
DenseMap<AssertingVH<GetElementPtrInst>, int> LargeOffsetGEPID;

/// Keep track of SExt promoted.
ValueToSExts ValToSExtendedUses;

/// True if the function has the OptSize attribute.
bool OptSize;

/// DataLayout for the Function being processed.
const DataLayout *DL = nullptr;

/// Building the dominator tree can be expensive, so we only build it
/// lazily and update it when required.
std::unique_ptr<DominatorTree> DT;

362public:
/// If encounter huge function, we need to limit the build time.
bool IsHugeFunc = false;

/// FreshBBs is like worklist, it collected the updated BBs which need
/// to be optimized again.
/// Note: Consider building time in this pass, when a BB updated, we need
/// to insert such BB into FreshBBs for huge function.
SmallSet<BasicBlock *, 32> FreshBBs;

static char ID; // Pass identification, replacement for typeid

CodeGenPrepare() : FunctionPass(ID) {
  initializeCodeGenPreparePass(*PassRegistry::getPassRegistry());
}

bool runOnFunction(Function &F) override;

StringRef getPassName() const override { return "CodeGen Prepare"; }

void getAnalysisUsage(AnalysisUsage &AU) const override {
  // FIXME: When we can selectively preserve passes, preserve the domtree.
  AU.addRequired<ProfileSummaryInfoWrapperPass>();
  AU.addRequired<TargetLibraryInfoWrapperPass>();
  AU.addRequired<TargetPassConfig>();
  AU.addRequired<TargetTransformInfoWrapperPass>();
  AU.addRequired<LoopInfoWrapperPass>();
  AU.addUsedIfAvailable<BasicBlockSectionsProfileReader>();
}

392private:
template <typename F>
void resetIteratorIfInvalidatedWhileCalling(BasicBlock *BB, F f) {
  // Substituting can cause recursive simplifications, which can invalidate
  // our iterator.  Use a WeakTrackingVH to hold onto it in case this
  // happens.
  Value *CurValue = &*CurInstIterator;
  WeakTrackingVH IterHandle(CurValue);

  f();

  // If the iterator instruction was recursively deleted, start over at the
  // start of the block.
  if (IterHandle != CurValue) {
    CurInstIterator = BB->begin();
    SunkAddrs.clear();
  }
}

// Get the DominatorTree, building if necessary.
DominatorTree &getDT(Function &F) {
  if (!DT)
    DT = std::make_unique<DominatorTree>(F);
  return *DT;
}

void removeAllAssertingVHReferences(Value *V);
bool eliminateAssumptions(Function &F);
bool eliminateFallThrough(Function &F);
bool eliminateMostlyEmptyBlocks(Function &F);
BasicBlock *findDestBlockOfMergeableEmptyBlock(BasicBlock *BB);
bool canMergeBlocks(const BasicBlock *BB, const BasicBlock *DestBB) const;
void eliminateMostlyEmptyBlock(BasicBlock *BB);
bool isMergingEmptyBlockProfitable(BasicBlock *BB, BasicBlock *DestBB,
                                   bool isPreheader);
bool makeBitReverse(Instruction &I);
bool optimizeBlock(BasicBlock &BB, ModifyDT &ModifiedDT);
bool optimizeInst(Instruction *I, ModifyDT &ModifiedDT);
bool optimizeMemoryInst(Instruction *MemoryInst, Value *Addr, Type *AccessTy,
                        unsigned AddrSpace);
bool optimizeGatherScatterInst(Instruction *MemoryInst, Value *Ptr);
bool optimizeInlineAsmInst(CallInst *CS);
bool optimizeCallInst(CallInst *CI, ModifyDT &ModifiedDT);
bool optimizeExt(Instruction *&I);
bool optimizeExtUses(Instruction *I);
bool optimizeLoadExt(LoadInst *Load);
bool optimizeShiftInst(BinaryOperator *BO);
bool optimizeFunnelShift(IntrinsicInst *Fsh);
bool optimizeSelectInst(SelectInst *SI);
bool optimizeShuffleVectorInst(ShuffleVectorInst *SVI);
bool optimizeSwitchType(SwitchInst *SI);
bool optimizeSwitchPhiConstants(SwitchInst *SI);
bool optimizeSwitchInst(SwitchInst *SI);
bool optimizeExtractElementInst(Instruction *Inst);
bool dupRetToEnableTailCallOpts(BasicBlock *BB, ModifyDT &ModifiedDT);
bool fixupDbgValue(Instruction *I);
bool placeDbgValues(Function &F);
bool placePseudoProbes(Function &F);
bool canFormExtLd(const SmallVectorImpl<Instruction *> &MovedExts,
                  LoadInst *&LI, Instruction *&Inst, bool HasPromoted);
bool tryToPromoteExts(TypePromotionTransaction &TPT,
                      const SmallVectorImpl<Instruction *> &Exts,
                      SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
                      unsigned CreatedInstsCost = 0);
bool mergeSExts(Function &F);
bool splitLargeGEPOffsets();
bool optimizePhiType(PHINode *Inst, SmallPtrSetImpl<PHINode *> &Visited,
                     SmallPtrSetImpl<Instruction *> &DeletedInstrs);
bool optimizePhiTypes(Function &F);
bool performAddressTypePromotion(
    Instruction *&Inst, bool AllowPromotionWithoutCommonHeader,
    bool HasPromoted, TypePromotionTransaction &TPT,
    SmallVectorImpl<Instruction *> &SpeculativelyMovedExts);
bool splitBranchCondition(Function &F, ModifyDT &ModifiedDT);
bool simplifyOffsetableRelocate(GCStatepointInst &I);

bool tryToSinkFreeOperands(Instruction *I);
bool replaceMathCmpWithIntrinsic(BinaryOperator *BO, Value *Arg0, Value *Arg1,
                                 CmpInst *Cmp, Intrinsic::ID IID);
bool optimizeCmp(CmpInst *Cmp, ModifyDT &ModifiedDT);
bool combineToUSubWithOverflow(CmpInst *Cmp, ModifyDT &ModifiedDT);
bool combineToUAddWithOverflow(CmpInst *Cmp, ModifyDT &ModifiedDT);
void verifyBFIUpdates(Function &F);
475};

477} // end anonymous namespace

479char CodeGenPrepare::ID = 0;

481INITIALIZE_PASS_BEGIN(CodeGenPrepare, DEBUG_TYPE,static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
                    "Optimize for code generation", false, false)static void *initializeCodeGenPreparePassOnce(PassRegistry &
Registry) {
483INITIALIZE_PASS_DEPENDENCY(BasicBlockSectionsProfileReader)initializeBasicBlockSectionsProfileReaderPass(Registry);
484INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)initializeLoopInfoWrapperPassPass(Registry);
485INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)initializeProfileSummaryInfoWrapperPassPass(Registry);
486INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
487INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)initializeTargetPassConfigPass(Registry);
488INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)initializeTargetTransformInfoWrapperPassPass(Registry);
489INITIALIZE_PASS_END(CodeGenPrepare, DEBUG_TYPE, "Optimize for code generation",PassInfo *PI = new PassInfo( "Optimize for code generation", "codegenprepare"
, &CodeGenPrepare::ID, PassInfo::NormalCtor_t(callDefaultCtor
<CodeGenPrepare>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeCodeGenPreparePassFlag
; void llvm::initializeCodeGenPreparePass(PassRegistry &Registry
) { llvm::call_once(InitializeCodeGenPreparePassFlag, initializeCodeGenPreparePassOnce
, std::ref(Registry)); }
                  false, false)PassInfo *PI = new PassInfo( "Optimize for code generation", "codegenprepare"
, &CodeGenPrepare::ID, PassInfo::NormalCtor_t(callDefaultCtor
<CodeGenPrepare>), false, false); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeCodeGenPreparePassFlag
; void llvm::initializeCodeGenPreparePass(PassRegistry &Registry
) { llvm::call_once(InitializeCodeGenPreparePassFlag, initializeCodeGenPreparePassOnce
, std::ref(Registry)); }

492FunctionPass *llvm::createCodeGenPreparePass() { return new CodeGenPrepare(); }

494bool CodeGenPrepare::runOnFunction(Function &F) {
if (skipFunction(F))
  return false;

DL = &F.getParent()->getDataLayout();

bool EverMadeChange = false;
// Clear per function information.
InsertedInsts.clear();
PromotedInsts.clear();
FreshBBs.clear();

TM = &getAnalysis<TargetPassConfig>().getTM<TargetMachine>();
SubtargetInfo = TM->getSubtargetImpl(F);
TLI = SubtargetInfo->getTargetLowering();
TRI = SubtargetInfo->getRegisterInfo();
TLInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
BPI.reset(new BranchProbabilityInfo(F, *LI));
BFI.reset(new BlockFrequencyInfo(F, *BPI, *LI));
PSI = &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
BBSectionsProfileReader =
    getAnalysisIfAvailable<BasicBlockSectionsProfileReader>();
OptSize = F.hasOptSize();
// Use the basic-block-sections profile to promote hot functions to .text.hot
// if requested.
if (BBSectionsGuidedSectionPrefix && BBSectionsProfileReader &&
    BBSectionsProfileReader->isFunctionHot(F.getName())) {
  F.setSectionPrefix("hot");
} else if (ProfileGuidedSectionPrefix) {
  // The hot attribute overwrites profile count based hotness while profile
  // counts based hotness overwrite the cold attribute.
  // This is a conservative behabvior.
  if (F.hasFnAttribute(Attribute::Hot) ||
      PSI->isFunctionHotInCallGraph(&F, *BFI))
    F.setSectionPrefix("hot");
  // If PSI shows this function is not hot, we will placed the function
  // into unlikely section if (1) PSI shows this is a cold function, or
  // (2) the function has a attribute of cold.
  else if (PSI->isFunctionColdInCallGraph(&F, *BFI) ||
           F.hasFnAttribute(Attribute::Cold))
    F.setSectionPrefix("unlikely");
  else if (ProfileUnknownInSpecialSection && PSI->hasPartialSampleProfile() &&
           PSI->isFunctionHotnessUnknown(F))
    F.setSectionPrefix("unknown");
}

/// This optimization identifies DIV instructions that can be
/// profitably bypassed and carried out with a shorter, faster divide.
if (!OptSize && !PSI->hasHugeWorkingSetSize() && TLI->isSlowDivBypassed()) {
  const DenseMap<unsigned int, unsigned int> &BypassWidths =
      TLI->getBypassSlowDivWidths();
  BasicBlock *BB = &*F.begin();
  while (BB != nullptr) {
    // bypassSlowDivision may create new BBs, but we don't want to reapply the
    // optimization to those blocks.
    BasicBlock *Next = BB->getNextNode();
    // F.hasOptSize is already checked in the outer if statement.
    if (!llvm::shouldOptimizeForSize(BB, PSI, BFI.get()))
      EverMadeChange |= bypassSlowDivision(BB, BypassWidths);
    BB = Next;
  }
}

// Get rid of @llvm.assume builtins before attempting to eliminate empty
// blocks, since there might be blocks that only contain @llvm.assume calls
// (plus arguments that we can get rid of).
EverMadeChange |= eliminateAssumptions(F);

// Eliminate blocks that contain only PHI nodes and an
// unconditional branch.
EverMadeChange |= eliminateMostlyEmptyBlocks(F);

ModifyDT ModifiedDT = ModifyDT::NotModifyDT;
if (!DisableBranchOpts)
  EverMadeChange |= splitBranchCondition(F, ModifiedDT);

// Split some critical edges where one of the sources is an indirect branch,
// to help generate sane code for PHIs involving such edges.
EverMadeChange |=
    SplitIndirectBrCriticalEdges(F, /*IgnoreBlocksWithoutPHI=*/true);

// If we are optimzing huge function, we need to consider the build time.
// Because the basic algorithm's complex is near O(N!).
IsHugeFunc = F.size() > HugeFuncThresholdInCGPP;

bool MadeChange = true;
bool FuncIterated = false;
while (MadeChange) {
  MadeChange = false;
  DT.reset();

  for (BasicBlock &BB : llvm::make_early_inc_range(F)) {
    if (FuncIterated && !FreshBBs.contains(&BB))
      continue;

    ModifyDT ModifiedDTOnIteration = ModifyDT::NotModifyDT;
    bool Changed = optimizeBlock(BB, ModifiedDTOnIteration);

    MadeChange |= Changed;
    if (IsHugeFunc) {
      // If the BB is updated, it may still has chance to be optimized.
      // This usually happen at sink optimization.
      // For example:
      //
      // bb0：
      // %and = and i32 %a, 4
      // %cmp = icmp eq i32 %and, 0
      //
      // If the %cmp sink to other BB, the %and will has chance to sink.
      if (Changed)
        FreshBBs.insert(&BB);
      else if (FuncIterated)
        FreshBBs.erase(&BB);

      if (ModifiedDTOnIteration == ModifyDT::ModifyBBDT)
        DT.reset();
    } else {
      // For small/normal functions, we restart BB iteration if the dominator
      // tree of the Function was changed.
      if (ModifiedDTOnIteration != ModifyDT::NotModifyDT)
        break;
    }
  }
  // We have iterated all the BB in the (only work for huge) function.
  FuncIterated = IsHugeFunc;

  if (EnableTypePromotionMerge && !ValToSExtendedUses.empty())
    MadeChange |= mergeSExts(F);
  if (!LargeOffsetGEPMap.empty())
    MadeChange |= splitLargeGEPOffsets();
  MadeChange |= optimizePhiTypes(F);

  if (MadeChange)
    eliminateFallThrough(F);

  // Really free removed instructions during promotion.
  for (Instruction *I : RemovedInsts)
    I->deleteValue();

  EverMadeChange |= MadeChange;
  SeenChainsForSExt.clear();
  ValToSExtendedUses.clear();
  RemovedInsts.clear();
  LargeOffsetGEPMap.clear();
  LargeOffsetGEPID.clear();
}

NewGEPBases.clear();
SunkAddrs.clear();

if (!DisableBranchOpts) {
  MadeChange = false;
  // Use a set vector to get deterministic iteration order. The order the
  // blocks are removed may affect whether or not PHI nodes in successors
  // are removed.
  SmallSetVector<BasicBlock *, 8> WorkList;
  for (BasicBlock &BB : F) {
    SmallVector<BasicBlock *, 2> Successors(successors(&BB));
    MadeChange |= ConstantFoldTerminator(&BB, true);
    if (!MadeChange)
      continue;

    for (BasicBlock *Succ : Successors)
      if (pred_empty(Succ))
        WorkList.insert(Succ);
  }

  // Delete the dead blocks and any of their dead successors.
  MadeChange |= !WorkList.empty();
  while (!WorkList.empty()) {
    BasicBlock *BB = WorkList.pop_back_val();
    SmallVector<BasicBlock *, 2> Successors(successors(BB));

    DeleteDeadBlock(BB);

    for (BasicBlock *Succ : Successors)
      if (pred_empty(Succ))
        WorkList.insert(Succ);
  }

  // Merge pairs of basic blocks with unconditional branches, connected by
  // a single edge.
  if (EverMadeChange || MadeChange)
    MadeChange |= eliminateFallThrough(F);

  EverMadeChange |= MadeChange;
}

if (!DisableGCOpts) {
  SmallVector<GCStatepointInst *, 2> Statepoints;
  for (BasicBlock &BB : F)
    for (Instruction &I : BB)
      if (auto *SP = dyn_cast<GCStatepointInst>(&I))
        Statepoints.push_back(SP);
  for (auto &I : Statepoints)
    EverMadeChange |= simplifyOffsetableRelocate(*I);
}

// Do this last to clean up use-before-def scenarios introduced by other
// preparatory transforms.
EverMadeChange |= placeDbgValues(F);
EverMadeChange |= placePseudoProbes(F);

699#ifndef NDEBUG
if (VerifyBFIUpdates)
  verifyBFIUpdates(F);
702#endif

return EverMadeChange;
705}

707bool CodeGenPrepare::eliminateAssumptions(Function &F) {
bool MadeChange = false;
for (BasicBlock &BB : F) {
  CurInstIterator = BB.begin();
  while (CurInstIterator != BB.end()) {
    Instruction *I = &*(CurInstIterator++);
    if (auto *Assume = dyn_cast<AssumeInst>(I)) {
      MadeChange = true;
      Value *Operand = Assume->getOperand(0);
      Assume->eraseFromParent();

      resetIteratorIfInvalidatedWhileCalling(&BB, [&]() {
        RecursivelyDeleteTriviallyDeadInstructions(Operand, TLInfo, nullptr);
      });
    }
  }
}
return MadeChange;
725}

727/// An instruction is about to be deleted, so remove all references to it in our
728/// GEP-tracking data strcutures.
729void CodeGenPrepare::removeAllAssertingVHReferences(Value *V) {
LargeOffsetGEPMap.erase(V);
NewGEPBases.erase(V);

auto GEP = dyn_cast<GetElementPtrInst>(V);
if (!GEP)
  return;

LargeOffsetGEPID.erase(GEP);

auto VecI = LargeOffsetGEPMap.find(GEP->getPointerOperand());
if (VecI == LargeOffsetGEPMap.end())
  return;

auto &GEPVector = VecI->second;
llvm::erase_if(GEPVector, [=](auto &Elt) { return Elt.first == GEP; });

if (GEPVector.empty())
  LargeOffsetGEPMap.erase(VecI);
748}

750// Verify BFI has been updated correctly by recomputing BFI and comparing them.
751void LLVM_ATTRIBUTE_UNUSED__attribute__((__unused__)) CodeGenPrepare::verifyBFIUpdates(Function &F) {
DominatorTree NewDT(F);
LoopInfo NewLI(NewDT);
BranchProbabilityInfo NewBPI(F, NewLI, TLInfo);
BlockFrequencyInfo NewBFI(F, NewBPI, NewLI);
NewBFI.verifyMatch(*BFI);
757}

759/// Merge basic blocks which are connected by a single edge, where one of the
760/// basic blocks has a single successor pointing to the other basic block,
761/// which has a single predecessor.
762bool CodeGenPrepare::eliminateFallThrough(Function &F) {
bool Changed = false;
// Scan all of the blocks in the function, except for the entry block.
// Use a temporary array to avoid iterator being invalidated when
// deleting blocks.
SmallVector<WeakTrackingVH, 16> Blocks;
for (auto &Block : llvm::drop_begin(F))
  Blocks.push_back(&Block);

SmallSet<WeakTrackingVH, 16> Preds;
for (auto &Block : Blocks) {
  auto *BB = cast_or_null<BasicBlock>(Block);
  if (!BB)
    continue;
  // If the destination block has a single pred, then this is a trivial
  // edge, just collapse it.
  BasicBlock *SinglePred = BB->getSinglePredecessor();

  // Don't merge if BB's address is taken.
  if (!SinglePred || SinglePred == BB || BB->hasAddressTaken())
    continue;

  BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator());
  if (Term && !Term->isConditional()) {
    Changed = true;
    LLVM_DEBUG(dbgs() << "To merge:\n" << *BB << "\n\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "To merge:\n" << *
BB << "\n\n\n"; } } while (false);

    // Merge BB into SinglePred and delete it.
    MergeBlockIntoPredecessor(BB);
    Preds.insert(SinglePred);

    if (IsHugeFunc) {
      // Update FreshBBs to optimize the merged BB.
      FreshBBs.insert(SinglePred);
      FreshBBs.erase(BB);
    }
  }
}

// (Repeatedly) merging blocks into their predecessors can create redundant
// debug intrinsics.
for (const auto &Pred : Preds)
  if (auto *BB = cast_or_null<BasicBlock>(Pred))
    RemoveRedundantDbgInstrs(BB);

return Changed;
808}

810/// Find a destination block from BB if BB is mergeable empty block.
811BasicBlock *CodeGenPrepare::findDestBlockOfMergeableEmptyBlock(BasicBlock *BB) {
// If this block doesn't end with an uncond branch, ignore it.
BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
if (!BI || !BI->isUnconditional())
  return nullptr;

// If the instruction before the branch (skipping debug info) isn't a phi
// node, then other stuff is happening here.
BasicBlock::iterator BBI = BI->getIterator();
if (BBI != BB->begin()) {
  --BBI;
  while (isa<DbgInfoIntrinsic>(BBI)) {
    if (BBI == BB->begin())
      break;
    --BBI;
  }
  if (!isa<DbgInfoIntrinsic>(BBI) && !isa<PHINode>(BBI))
    return nullptr;
}

// Do not break infinite loops.
BasicBlock *DestBB = BI->getSuccessor(0);
if (DestBB == BB)
  return nullptr;

if (!canMergeBlocks(BB, DestBB))
  DestBB = nullptr;

return DestBB;
840}

842/// Eliminate blocks that contain only PHI nodes, debug info directives, and an
843/// unconditional branch. Passes before isel (e.g. LSR/loopsimplify) often split
844/// edges in ways that are non-optimal for isel. Start by eliminating these
845/// blocks so we can split them the way we want them.
846bool CodeGenPrepare::eliminateMostlyEmptyBlocks(Function &F) {
SmallPtrSet<BasicBlock *, 16> Preheaders;
SmallVector<Loop *, 16> LoopList(LI->begin(), LI->end());
while (!LoopList.empty()) {
  Loop *L = LoopList.pop_back_val();
  llvm::append_range(LoopList, *L);
  if (BasicBlock *Preheader = L->getLoopPreheader())
    Preheaders.insert(Preheader);
}

bool MadeChange = false;
// Copy blocks into a temporary array to avoid iterator invalidation issues
// as we remove them.
// Note that this intentionally skips the entry block.
SmallVector<WeakTrackingVH, 16> Blocks;
for (auto &Block : llvm::drop_begin(F))
  Blocks.push_back(&Block);

for (auto &Block : Blocks) {
  BasicBlock *BB = cast_or_null<BasicBlock>(Block);
  if (!BB)
    continue;
  BasicBlock *DestBB = findDestBlockOfMergeableEmptyBlock(BB);
  if (!DestBB ||
      !isMergingEmptyBlockProfitable(BB, DestBB, Preheaders.count(BB)))
    continue;

  eliminateMostlyEmptyBlock(BB);
  MadeChange = true;
}
return MadeChange;
877}

879bool CodeGenPrepare::isMergingEmptyBlockProfitable(BasicBlock *BB,
                                                 BasicBlock *DestBB,
                                                 bool isPreheader) {
// Do not delete loop preheaders if doing so would create a critical edge.
// Loop preheaders can be good locations to spill registers. If the
// preheader is deleted and we create a critical edge, registers may be
// spilled in the loop body instead.
if (!DisablePreheaderProtect && isPreheader &&
    !(BB->getSinglePredecessor() &&
      BB->getSinglePredecessor()->getSingleSuccessor()))
  return false;

// Skip merging if the block's successor is also a successor to any callbr
// that leads to this block.
// FIXME: Is this really needed? Is this a correctness issue?
for (BasicBlock *Pred : predecessors(BB)) {
  if (auto *CBI = dyn_cast<CallBrInst>((Pred)->getTerminator()))
    for (unsigned i = 0, e = CBI->getNumSuccessors(); i != e; ++i)
      if (DestBB == CBI->getSuccessor(i))
        return false;
}

// Try to skip merging if the unique predecessor of BB is terminated by a
// switch or indirect branch instruction, and BB is used as an incoming block
// of PHIs in DestBB. In such case, merging BB and DestBB would cause ISel to
// add COPY instructions in the predecessor of BB instead of BB (if it is not
// merged). Note that the critical edge created by merging such blocks wont be
// split in MachineSink because the jump table is not analyzable. By keeping
// such empty block (BB), ISel will place COPY instructions in BB, not in the
// predecessor of BB.
BasicBlock *Pred = BB->getUniquePredecessor();
if (!Pred || !(isa<SwitchInst>(Pred->getTerminator()) ||
               isa<IndirectBrInst>(Pred->getTerminator())))
  return true;

if (BB->getTerminator() != BB->getFirstNonPHIOrDbg())
  return true;

// We use a simple cost heuristic which determine skipping merging is
// profitable if the cost of skipping merging is less than the cost of
// merging : Cost(skipping merging) < Cost(merging BB), where the
// Cost(skipping merging) is Freq(BB) * (Cost(Copy) + Cost(Branch)), and
// the Cost(merging BB) is Freq(Pred) * Cost(Copy).
// Assuming Cost(Copy) == Cost(Branch), we could simplify it to :
//   Freq(Pred) / Freq(BB) > 2.
// Note that if there are multiple empty blocks sharing the same incoming
// value for the PHIs in the DestBB, we consider them together. In such
// case, Cost(merging BB) will be the sum of their frequencies.

if (!isa<PHINode>(DestBB->begin()))
  return true;

SmallPtrSet<BasicBlock *, 16> SameIncomingValueBBs;

// Find all other incoming blocks from which incoming values of all PHIs in
// DestBB are the same as the ones from BB.
for (BasicBlock *DestBBPred : predecessors(DestBB)) {
  if (DestBBPred == BB)
    continue;

  if (llvm::all_of(DestBB->phis(), [&](const PHINode &DestPN) {
        return DestPN.getIncomingValueForBlock(BB) ==
               DestPN.getIncomingValueForBlock(DestBBPred);
      }))
    SameIncomingValueBBs.insert(DestBBPred);
}

// See if all BB's incoming values are same as the value from Pred. In this
// case, no reason to skip merging because COPYs are expected to be place in
// Pred already.
if (SameIncomingValueBBs.count(Pred))
  return true;

BlockFrequency PredFreq = BFI->getBlockFreq(Pred);
BlockFrequency BBFreq = BFI->getBlockFreq(BB);

for (auto *SameValueBB : SameIncomingValueBBs)
  if (SameValueBB->getUniquePredecessor() == Pred &&
      DestBB == findDestBlockOfMergeableEmptyBlock(SameValueBB))
    BBFreq += BFI->getBlockFreq(SameValueBB);

return PredFreq.getFrequency() <=
       BBFreq.getFrequency() * FreqRatioToSkipMerge;
962}

964/// Return true if we can merge BB into DestBB if there is a single
965/// unconditional branch between them, and BB contains no other non-phi
966/// instructions.
967bool CodeGenPrepare::canMergeBlocks(const BasicBlock *BB,
                                  const BasicBlock *DestBB) const {
// We only want to eliminate blocks whose phi nodes are used by phi nodes in
// the successor.  If there are more complex condition (e.g. preheaders),
// don't mess around with them.
for (const PHINode &PN : BB->phis()) {
  for (const User *U : PN.users()) {
    const Instruction *UI = cast<Instruction>(U);
    if (UI->getParent() != DestBB || !isa<PHINode>(UI))
      return false;
    // If User is inside DestBB block and it is a PHINode then check
    // incoming value. If incoming value is not from BB then this is
    // a complex condition (e.g. preheaders) we want to avoid here.
    if (UI->getParent() == DestBB) {
      if (const PHINode *UPN = dyn_cast<PHINode>(UI))
        for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) {
          Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I));
          if (Insn && Insn->getParent() == BB &&
              Insn->getParent() != UPN->getIncomingBlock(I))
            return false;
        }
    }
  }
}

// If BB and DestBB contain any common predecessors, then the phi nodes in BB
// and DestBB may have conflicting incoming values for the block.  If so, we
// can't merge the block.
const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
if (!DestBBPN)
  return true; // no conflict.

// Collect the preds of BB.
SmallPtrSet<const BasicBlock *, 16> BBPreds;
if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
  // It is faster to get preds from a PHI than with pred_iterator.
  for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
    BBPreds.insert(BBPN->getIncomingBlock(i));
} else {
  BBPreds.insert(pred_begin(BB), pred_end(BB));
}

// Walk the preds of DestBB.
for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
  BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
  if (BBPreds.count(Pred)) { // Common predecessor?
    for (const PHINode &PN : DestBB->phis()) {
      const Value *V1 = PN.getIncomingValueForBlock(Pred);
      const Value *V2 = PN.getIncomingValueForBlock(BB);

      // If V2 is a phi node in BB, look up what the mapped value will be.
      if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
        if (V2PN->getParent() == BB)
          V2 = V2PN->getIncomingValueForBlock(Pred);

      // If there is a conflict, bail out.
      if (V1 != V2)
        return false;
    }
  }
}

return true;
1030}

1032/// Replace all old uses with new ones, and push the updated BBs into FreshBBs.
1033static void replaceAllUsesWith(Value *Old, Value *New,
                             SmallSet<BasicBlock *, 32> &FreshBBs,
                             bool IsHuge) {
auto *OldI = dyn_cast<Instruction>(Old);
if (OldI) {
  for (Value::user_iterator UI = OldI->user_begin(), E = OldI->user_end();
       UI != E; ++UI) {
    Instruction *User = cast<Instruction>(*UI);
    if (IsHuge)
      FreshBBs.insert(User->getParent());
  }
}
Old->replaceAllUsesWith(New);
1046}

1048/// Eliminate a basic block that has only phi's and an unconditional branch in
1049/// it.
1050void CodeGenPrepare::eliminateMostlyEmptyBlock(BasicBlock *BB) {
BranchInst *BI = cast<BranchInst>(BB->getTerminator());
BasicBlock *DestBB = BI->getSuccessor(0);

LLVM_DEBUG(dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"
 << *BB << *DestBB; } } while (false)
                  << *BB << *DestBB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n"
 << *BB << *DestBB; } } while (false);

// If the destination block has a single pred, then this is a trivial edge,
// just collapse it.
if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) {
  if (SinglePred != DestBB) {
    assert(SinglePred == BB &&(static_cast <bool> (SinglePred == BB && "Single predecessor not the same as predecessor"
) ? void (0) : __assert_fail ("SinglePred == BB && \"Single predecessor not the same as predecessor\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1062, __extension__ __PRETTY_FUNCTION__
))
           "Single predecessor not the same as predecessor")(static_cast <bool> (SinglePred == BB && "Single predecessor not the same as predecessor"
) ? void (0) : __assert_fail ("SinglePred == BB && \"Single predecessor not the same as predecessor\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1062, __extension__ __PRETTY_FUNCTION__
));
    // Merge DestBB into SinglePred/BB and delete it.
    MergeBlockIntoPredecessor(DestBB);
    // Note: BB(=SinglePred) will not be deleted on this path.
    // DestBB(=its single successor) is the one that was deleted.
    LLVM_DEBUG(dbgs() << "AFTER:\n" << *SinglePred << "\n\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "AFTER:\n" << *SinglePred
 << "\n\n\n"; } } while (false);

    if (IsHugeFunc) {
      // Update FreshBBs to optimize the merged BB.
      FreshBBs.insert(SinglePred);
      FreshBBs.erase(DestBB);
    }
    return;
  }
}

// Otherwise, we have multiple predecessors of BB.  Update the PHIs in DestBB
// to handle the new incoming edges it is about to have.
for (PHINode &PN : DestBB->phis()) {
  // Remove the incoming value for BB, and remember it.
  Value *InVal = PN.removeIncomingValue(BB, false);

  // Two options: either the InVal is a phi node defined in BB or it is some
  // value that dominates BB.
  PHINode *InValPhi = dyn_cast<PHINode>(InVal);
  if (InValPhi && InValPhi->getParent() == BB) {
    // Add all of the input values of the input PHI as inputs of this phi.
    for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
      PN.addIncoming(InValPhi->getIncomingValue(i),
                     InValPhi->getIncomingBlock(i));
  } else {
    // Otherwise, add one instance of the dominating value for each edge that
    // we will be adding.
    if (PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
      for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
        PN.addIncoming(InVal, BBPN->getIncomingBlock(i));
    } else {
      for (BasicBlock *Pred : predecessors(BB))
        PN.addIncoming(InVal, Pred);
    }
  }
}

// The PHIs are now updated, change everything that refers to BB to use
// DestBB and remove BB.
BB->replaceAllUsesWith(DestBB);
BB->eraseFromParent();
++NumBlocksElim;

LLVM_DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "AFTER:\n" << *DestBB
 << "\n\n\n"; } } while (false);
1112}

1114// Computes a map of base pointer relocation instructions to corresponding
1115// derived pointer relocation instructions given a vector of all relocate calls
1116static void computeBaseDerivedRelocateMap(
  const SmallVectorImpl<GCRelocateInst *> &AllRelocateCalls,
  DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>>
      &RelocateInstMap) {
// Collect information in two maps: one primarily for locating the base object
// while filling the second map; the second map is the final structure holding
// a mapping between Base and corresponding Derived relocate calls
DenseMap<std::pair<unsigned, unsigned>, GCRelocateInst *> RelocateIdxMap;
for (auto *ThisRelocate : AllRelocateCalls) {
  auto K = std::make_pair(ThisRelocate->getBasePtrIndex(),
                          ThisRelocate->getDerivedPtrIndex());
  RelocateIdxMap.insert(std::make_pair(K, ThisRelocate));
}
for (auto &Item : RelocateIdxMap) {
  std::pair<unsigned, unsigned> Key = Item.first;
  if (Key.first == Key.second)
    // Base relocation: nothing to insert
    continue;

  GCRelocateInst *I = Item.second;
  auto BaseKey = std::make_pair(Key.first, Key.first);

  // We're iterating over RelocateIdxMap so we cannot modify it.
  auto MaybeBase = RelocateIdxMap.find(BaseKey);
  if (MaybeBase == RelocateIdxMap.end())
    // TODO: We might want to insert a new base object relocate and gep off
    // that, if there are enough derived object relocates.
    continue;

  RelocateInstMap[MaybeBase->second].push_back(I);
}
1147}

1149// Accepts a GEP and extracts the operands into a vector provided they're all
1150// small integer constants
1151static bool getGEPSmallConstantIntOffsetV(GetElementPtrInst *GEP,
                                        SmallVectorImpl<Value *> &OffsetV) {
for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
  // Only accept small constant integer operands
  auto *Op = dyn_cast<ConstantInt>(GEP->getOperand(i));
  if (!Op || Op->getZExtValue() > 20)
    return false;
}

for (unsigned i = 1; i < GEP->getNumOperands(); i++)
  OffsetV.push_back(GEP->getOperand(i));
return true;
1163}

1165// Takes a RelocatedBase (base pointer relocation instruction) and Targets to
1166// replace, computes a replacement, and affects it.
1167static bool
1168simplifyRelocatesOffABase(GCRelocateInst *RelocatedBase,
                        const SmallVectorImpl<GCRelocateInst *> &Targets) {
bool MadeChange = false;
// We must ensure the relocation of derived pointer is defined after
// relocation of base pointer. If we find a relocation corresponding to base
// defined earlier than relocation of base then we move relocation of base
// right before found relocation. We consider only relocation in the same
// basic block as relocation of base. Relocations from other basic block will
// be skipped by optimization and we do not care about them.
for (auto R = RelocatedBase->getParent()->getFirstInsertionPt();
7
←
Loop condition is false. Execution continues on line 1186→
     &*R != RelocatedBase; ++R)
6
←
Assuming the condition is false→
  if (auto *RI = dyn_cast<GCRelocateInst>(R))
    if (RI->getStatepoint() == RelocatedBase->getStatepoint())
      if (RI->getBasePtrIndex() == RelocatedBase->getBasePtrIndex()) {
        RelocatedBase->moveBefore(RI);
        break;
      }

for (GCRelocateInst *ToReplace : Targets) {
8
←
Assuming '__begin1' is not equal to '__end1'→
  assert(ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() &&(static_cast <bool> (ToReplace->getBasePtrIndex() ==
 RelocatedBase->getBasePtrIndex() && "Not relocating a derived object of the original base object"
) ? void (0) : __assert_fail ("ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() && \"Not relocating a derived object of the original base object\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1188, __extension__ __PRETTY_FUNCTION__
))
9
←
Assuming the condition is true→
10
←
'?' condition is true→
         "Not relocating a derived object of the original base object")(static_cast <bool> (ToReplace->getBasePtrIndex() ==
 RelocatedBase->getBasePtrIndex() && "Not relocating a derived object of the original base object"
) ? void (0) : __assert_fail ("ToReplace->getBasePtrIndex() == RelocatedBase->getBasePtrIndex() && \"Not relocating a derived object of the original base object\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1188, __extension__ __PRETTY_FUNCTION__
));
  if (ToReplace->getBasePtrIndex() == ToReplace->getDerivedPtrIndex()) {
11
←
Assuming the condition is false→
12
←
Taking false branch→
    // A duplicate relocate call. TODO: coalesce duplicates.
    continue;
  }

  if (RelocatedBase->getParent() != ToReplace->getParent()) {
13
←
Assuming the condition is false→
14
←
Taking false branch→
    // Base and derived relocates are in different basic blocks.
    // In this case transform is only valid when base dominates derived
    // relocate. However it would be too expensive to check dominance
    // for each such relocate, so we skip the whole transformation.
    continue;
  }

  Value *Base = ToReplace->getBasePtr();
15
←
'Base' initialized here→
  auto *Derived = dyn_cast<GetElementPtrInst>(ToReplace->getDerivedPtr());
16
←
Assuming the object is a 'CastReturnType'→
  if (!Derived16.1
'Derived' is non-null
 || Derived->getPointerOperand() != Base)
17
←
Assuming pointer value is null→
18
←
Taking false branch→
    continue;

  SmallVector<Value *, 2> OffsetV;
  if (!getGEPSmallConstantIntOffsetV(Derived, OffsetV))
    continue;

  // Create a Builder and replace the target callsite with a gep
  assert(RelocatedBase->getNextNode() &&(static_cast <bool> (RelocatedBase->getNextNode() &&
 "Should always have one since it's not a terminator") ? void
 (0) : __assert_fail ("RelocatedBase->getNextNode() && \"Should always have one since it's not a terminator\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1213, __extension__ __PRETTY_FUNCTION__
))
19
←
Taking false branch→
20
←
Assuming the condition is true→
21
←
'?' condition is true→
         "Should always have one since it's not a terminator")(static_cast <bool> (RelocatedBase->getNextNode() &&
 "Should always have one since it's not a terminator") ? void
 (0) : __assert_fail ("RelocatedBase->getNextNode() && \"Should always have one since it's not a terminator\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1213, __extension__ __PRETTY_FUNCTION__
));

  // Insert after RelocatedBase
  IRBuilder<> Builder(RelocatedBase->getNextNode());
  Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());

  // If gc_relocate does not match the actual type, cast it to the right type.
  // In theory, there must be a bitcast after gc_relocate if the type does not
  // match, and we should reuse it to get the derived pointer. But it could be
  // cases like this:
  // bb1:
  //  ...
  //  %g1 = call coldcc i8 addrspace(1)*
  //  @llvm.experimental.gc.relocate.p1i8(...) br label %merge
  //
  // bb2:
  //  ...
  //  %g2 = call coldcc i8 addrspace(1)*
  //  @llvm.experimental.gc.relocate.p1i8(...) br label %merge
  //
  // merge:
  //  %p1 = phi i8 addrspace(1)* [ %g1, %bb1 ], [ %g2, %bb2 ]
  //  %cast = bitcast i8 addrspace(1)* %p1 in to i32 addrspace(1)*
  //
  // In this case, we can not find the bitcast any more. So we insert a new
  // bitcast no matter there is already one or not. In this way, we can handle
  // all cases, and the extra bitcast should be optimized away in later
  // passes.
  Value *ActualRelocatedBase = RelocatedBase;
  if (RelocatedBase->getType() != Base->getType()) {
22
←
Called C++ object pointer is null
    ActualRelocatedBase =
        Builder.CreateBitCast(RelocatedBase, Base->getType());
  }
  Value *Replacement =
      Builder.CreateGEP(Derived->getSourceElementType(), ActualRelocatedBase,
                        ArrayRef(OffsetV));
  Replacement->takeName(ToReplace);
  // If the newly generated derived pointer's type does not match the original
  // derived pointer's type, cast the new derived pointer to match it. Same
  // reasoning as above.
  Value *ActualReplacement = Replacement;
  if (Replacement->getType() != ToReplace->getType()) {
    ActualReplacement =
        Builder.CreateBitCast(Replacement, ToReplace->getType());
  }
  ToReplace->replaceAllUsesWith(ActualReplacement);
  ToReplace->eraseFromParent();

  MadeChange = true;
}
return MadeChange;
1264}

1266// Turns this:
1267//
1268// %base = ...
1269// %ptr = gep %base + 15
1270// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
1271// %base' = relocate(%tok, i32 4, i32 4)
1272// %ptr' = relocate(%tok, i32 4, i32 5)
1273// %val = load %ptr'
1274//
1275// into this:
1276//
1277// %base = ...
1278// %ptr = gep %base + 15
1279// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
1280// %base' = gc.relocate(%tok, i32 4, i32 4)
1281// %ptr' = gep %base' + 15
1282// %val = load %ptr'
1283bool CodeGenPrepare::simplifyOffsetableRelocate(GCStatepointInst &I) {
bool MadeChange = false;
SmallVector<GCRelocateInst *, 2> AllRelocateCalls;
for (auto *U : I.users())
  if (GCRelocateInst *Relocate = dyn_cast<GCRelocateInst>(U))
    // Collect all the relocate calls associated with a statepoint
    AllRelocateCalls.push_back(Relocate);

// We need at least one base pointer relocation + one derived pointer
// relocation to mangle
if (AllRelocateCalls.size() < 2)
1
Assuming the condition is false→
2
←
Taking false branch→
  return false;

// RelocateInstMap is a mapping from the base relocate instruction to the
// corresponding derived relocate instructions
DenseMap<GCRelocateInst *, SmallVector<GCRelocateInst *, 2>> RelocateInstMap;
computeBaseDerivedRelocateMap(AllRelocateCalls, RelocateInstMap);
if (RelocateInstMap.empty())
3
←
Assuming the condition is false→
4
←
Taking false branch→
  return false;

for (auto &Item : RelocateInstMap)
  // Item.first is the RelocatedBase to offset against
  // Item.second is the vector of Targets to replace
  MadeChange = simplifyRelocatesOffABase(Item.first, Item.second);
5
←
Calling 'simplifyRelocatesOffABase'→
return MadeChange;
1308}

1310/// Sink the specified cast instruction into its user blocks.
1311static bool SinkCast(CastInst *CI) {
BasicBlock *DefBB = CI->getParent();

/// InsertedCasts - Only insert a cast in each block once.
DenseMap<BasicBlock *, CastInst *> InsertedCasts;

bool MadeChange = false;
for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
     UI != E;) {
  Use &TheUse = UI.getUse();
  Instruction *User = cast<Instruction>(*UI);

  // Figure out which BB this cast is used in.  For PHI's this is the
  // appropriate predecessor block.
  BasicBlock *UserBB = User->getParent();
  if (PHINode *PN = dyn_cast<PHINode>(User)) {
    UserBB = PN->getIncomingBlock(TheUse);
  }

  // Preincrement use iterator so we don't invalidate it.
  ++UI;

  // The first insertion point of a block containing an EH pad is after the
  // pad.  If the pad is the user, we cannot sink the cast past the pad.
  if (User->isEHPad())
    continue;

  // If the block selected to receive the cast is an EH pad that does not
  // allow non-PHI instructions before the terminator, we can't sink the
  // cast.
  if (UserBB->getTerminator()->isEHPad())
    continue;

  // If this user is in the same block as the cast, don't change the cast.
  if (UserBB == DefBB)
    continue;

  // If we have already inserted a cast into this block, use it.
  CastInst *&InsertedCast = InsertedCasts[UserBB];

  if (!InsertedCast) {
    BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
    assert(InsertPt != UserBB->end())(static_cast <bool> (InsertPt != UserBB->end()) ? void
 (0) : __assert_fail ("InsertPt != UserBB->end()", "llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1353, __extension__ __PRETTY_FUNCTION__));
    InsertedCast = CastInst::Create(CI->getOpcode(), CI->getOperand(0),
                                    CI->getType(), "", &*InsertPt);
    InsertedCast->setDebugLoc(CI->getDebugLoc());
  }

  // Replace a use of the cast with a use of the new cast.
  TheUse = InsertedCast;
  MadeChange = true;
  ++NumCastUses;
}

// If we removed all uses, nuke the cast.
if (CI->use_empty()) {
  salvageDebugInfo(*CI);
  CI->eraseFromParent();
  MadeChange = true;
}

return MadeChange;
1373}

1375/// If the specified cast instruction is a noop copy (e.g. it's casting from
1376/// one pointer type to another, i32->i8 on PPC), sink it into user blocks to
1377/// reduce the number of virtual registers that must be created and coalesced.
1378///
1379/// Return true if any changes are made.
1380static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI,
                                     const DataLayout &DL) {
// Sink only "cheap" (or nop) address-space casts.  This is a weaker condition
// than sinking only nop casts, but is helpful on some platforms.
if (auto *ASC = dyn_cast<AddrSpaceCastInst>(CI)) {
  if (!TLI.isFreeAddrSpaceCast(ASC->getSrcAddressSpace(),
                               ASC->getDestAddressSpace()))
    return false;
}

// If this is a noop copy,
EVT SrcVT = TLI.getValueType(DL, CI->getOperand(0)->getType());
EVT DstVT = TLI.getValueType(DL, CI->getType());

// This is an fp<->int conversion?
if (SrcVT.isInteger() != DstVT.isInteger())
  return false;

// If this is an extension, it will be a zero or sign extension, which
// isn't a noop.
if (SrcVT.bitsLT(DstVT))
  return false;

// If these values will be promoted, find out what they will be promoted
// to.  This helps us consider truncates on PPC as noop copies when they
// are.
if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
    TargetLowering::TypePromoteInteger)
  SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
if (TLI.getTypeAction(CI->getContext(), DstVT) ==
    TargetLowering::TypePromoteInteger)
  DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);

// If, after promotion, these are the same types, this is a noop copy.
if (SrcVT != DstVT)
  return false;

return SinkCast(CI);
1418}

1420// Match a simple increment by constant operation.  Note that if a sub is
1421// matched, the step is negated (as if the step had been canonicalized to
1422// an add, even though we leave the instruction alone.)
1423bool matchIncrement(const Instruction *IVInc, Instruction *&LHS,
                  Constant *&Step) {
if (match(IVInc, m_Add(m_Instruction(LHS), m_Constant(Step))) ||
    match(IVInc, m_ExtractValue<0>(m_Intrinsic<Intrinsic::uadd_with_overflow>(
                     m_Instruction(LHS), m_Constant(Step)))))
  return true;
if (match(IVInc, m_Sub(m_Instruction(LHS), m_Constant(Step))) ||
    match(IVInc, m_ExtractValue<0>(m_Intrinsic<Intrinsic::usub_with_overflow>(
                     m_Instruction(LHS), m_Constant(Step))))) {
  Step = ConstantExpr::getNeg(Step);
  return true;
}
return false;
1436}

1438/// If given \p PN is an inductive variable with value IVInc coming from the
1439/// backedge, and on each iteration it gets increased by Step, return pair
1440/// <IVInc, Step>. Otherwise, return std::nullopt.
1441static std::optional<std::pair<Instruction *, Constant *>>
1442getIVIncrement(const PHINode *PN, const LoopInfo *LI) {
const Loop *L = LI->getLoopFor(PN->getParent());
if (!L || L->getHeader() != PN->getParent() || !L->getLoopLatch())
  return std::nullopt;
auto *IVInc =
    dyn_cast<Instruction>(PN->getIncomingValueForBlock(L->getLoopLatch()));
if (!IVInc || LI->getLoopFor(IVInc->getParent()) != L)
  return std::nullopt;
Instruction *LHS = nullptr;
Constant *Step = nullptr;
if (matchIncrement(IVInc, LHS, Step) && LHS == PN)
  return std::make_pair(IVInc, Step);
return std::nullopt;
1455}

1457static bool isIVIncrement(const Value *V, const LoopInfo *LI) {
auto *I = dyn_cast<Instruction>(V);
if (!I)
  return false;
Instruction *LHS = nullptr;
Constant *Step = nullptr;
if (!matchIncrement(I, LHS, Step))
  return false;
if (auto *PN = dyn_cast<PHINode>(LHS))
  if (auto IVInc = getIVIncrement(PN, LI))
    return IVInc->first == I;
return false;
1469}

1471bool CodeGenPrepare::replaceMathCmpWithIntrinsic(BinaryOperator *BO,
                                               Value *Arg0, Value *Arg1,
                                               CmpInst *Cmp,
                                               Intrinsic::ID IID) {
auto IsReplacableIVIncrement = [this, &Cmp](BinaryOperator *BO) {
  if (!isIVIncrement(BO, LI))
    return false;
  const Loop *L = LI->getLoopFor(BO->getParent());
  assert(L && "L should not be null after isIVIncrement()")(static_cast <bool> (L && "L should not be null after isIVIncrement()"
) ? void (0) : __assert_fail ("L && \"L should not be null after isIVIncrement()\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1479, __extension__ __PRETTY_FUNCTION__
));
  // Do not risk on moving increment into a child loop.
  if (LI->getLoopFor(Cmp->getParent()) != L)
    return false;

  // Finally, we need to ensure that the insert point will dominate all
  // existing uses of the increment.

  auto &DT = getDT(*BO->getParent()->getParent());
  if (DT.dominates(Cmp->getParent(), BO->getParent()))
    // If we're moving up the dom tree, all uses are trivially dominated.
    // (This is the common case for code produced by LSR.)
    return true;

  // Otherwise, special case the single use in the phi recurrence.
  return BO->hasOneUse() && DT.dominates(Cmp->getParent(), L->getLoopLatch());
};
if (BO->getParent() != Cmp->getParent() && !IsReplacableIVIncrement(BO)) {
  // We used to use a dominator tree here to allow multi-block optimization.
  // But that was problematic because:
  // 1. It could cause a perf regression by hoisting the math op into the
  //    critical path.
  // 2. It could cause a perf regression by creating a value that was live
  //    across multiple blocks and increasing register pressure.
  // 3. Use of a dominator tree could cause large compile-time regression.
  //    This is because we recompute the DT on every change in the main CGP
  //    run-loop. The recomputing is probably unnecessary in many cases, so if
  //    that was fixed, using a DT here would be ok.
  //
  // There is one important particular case we still want to handle: if BO is
  // the IV increment. Important properties that make it profitable:
  // - We can speculate IV increment anywhere in the loop (as long as the
  //   indvar Phi is its only user);
  // - Upon computing Cmp, we effectively compute something equivalent to the
  //   IV increment (despite it loops differently in the IR). So moving it up
  //   to the cmp point does not really increase register pressure.
  return false;
}

// We allow matching the canonical IR (add X, C) back to (usubo X, -C).
if (BO->getOpcode() == Instruction::Add &&
    IID == Intrinsic::usub_with_overflow) {
  assert(isa<Constant>(Arg1) && "Unexpected input for usubo")(static_cast <bool> (isa<Constant>(Arg1) &&
 "Unexpected input for usubo") ? void (0) : __assert_fail ("isa<Constant>(Arg1) && \"Unexpected input for usubo\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1521, __extension__ __PRETTY_FUNCTION__
));
  Arg1 = ConstantExpr::getNeg(cast<Constant>(Arg1));
}

// Insert at the first instruction of the pair.
Instruction *InsertPt = nullptr;
for (Instruction &Iter : *Cmp->getParent()) {
  // If BO is an XOR, it is not guaranteed that it comes after both inputs to
  // the overflow intrinsic are defined.
  if ((BO->getOpcode() != Instruction::Xor && &Iter == BO) || &Iter == Cmp) {
    InsertPt = &Iter;
    break;
  }
}
assert(InsertPt != nullptr && "Parent block did not contain cmp or binop")(static_cast <bool> (InsertPt != nullptr && "Parent block did not contain cmp or binop"
) ? void (0) : __assert_fail ("InsertPt != nullptr && \"Parent block did not contain cmp or binop\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1535, __extension__ __PRETTY_FUNCTION__
));

IRBuilder<> Builder(InsertPt);
Value *MathOV = Builder.CreateBinaryIntrinsic(IID, Arg0, Arg1);
if (BO->getOpcode() != Instruction::Xor) {
  Value *Math = Builder.CreateExtractValue(MathOV, 0, "math");
  replaceAllUsesWith(BO, Math, FreshBBs, IsHugeFunc);
} else
  assert(BO->hasOneUse() &&(static_cast <bool> (BO->hasOneUse() && "Patterns with XOr should use the BO only in the compare"
) ? void (0) : __assert_fail ("BO->hasOneUse() && \"Patterns with XOr should use the BO only in the compare\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1544, __extension__ __PRETTY_FUNCTION__
))
         "Patterns with XOr should use the BO only in the compare")(static_cast <bool> (BO->hasOneUse() && "Patterns with XOr should use the BO only in the compare"
) ? void (0) : __assert_fail ("BO->hasOneUse() && \"Patterns with XOr should use the BO only in the compare\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1544, __extension__ __PRETTY_FUNCTION__
));
Value *OV = Builder.CreateExtractValue(MathOV, 1, "ov");
replaceAllUsesWith(Cmp, OV, FreshBBs, IsHugeFunc);
Cmp->eraseFromParent();
BO->eraseFromParent();
return true;
1550}

1552/// Match special-case patterns that check for unsigned add overflow.
1553static bool matchUAddWithOverflowConstantEdgeCases(CmpInst *Cmp,
                                                 BinaryOperator *&Add) {
// Add = add A, 1; Cmp = icmp eq A,-1 (overflow if A is max val)
// Add = add A,-1; Cmp = icmp ne A, 0 (overflow if A is non-zero)
Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1);

// We are not expecting non-canonical/degenerate code. Just bail out.
if (isa<Constant>(A))
  return false;

ICmpInst::Predicate Pred = Cmp->getPredicate();
if (Pred == ICmpInst::ICMP_EQ && match(B, m_AllOnes()))
  B = ConstantInt::get(B->getType(), 1);
else if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt()))
  B = ConstantInt::get(B->getType(), -1);
else
  return false;

// Check the users of the variable operand of the compare looking for an add
// with the adjusted constant.
for (User *U : A->users()) {
  if (match(U, m_Add(m_Specific(A), m_Specific(B)))) {
    Add = cast<BinaryOperator>(U);
    return true;
  }
}
return false;
1580}

1582/// Try to combine the compare into a call to the llvm.uadd.with.overflow
1583/// intrinsic. Return true if any changes were made.
1584bool CodeGenPrepare::combineToUAddWithOverflow(CmpInst *Cmp,
                                             ModifyDT &ModifiedDT) {
bool EdgeCase = false;
Value *A, *B;
BinaryOperator *Add;
if (!match(Cmp, m_UAddWithOverflow(m_Value(A), m_Value(B), m_BinOp(Add)))) {
  if (!matchUAddWithOverflowConstantEdgeCases(Cmp, Add))
    return false;
  // Set A and B in case we match matchUAddWithOverflowConstantEdgeCases.
  A = Add->getOperand(0);
  B = Add->getOperand(1);
  EdgeCase = true;
}

if (!TLI->shouldFormOverflowOp(ISD::UADDO,
                               TLI->getValueType(*DL, Add->getType()),
                               Add->hasNUsesOrMore(EdgeCase ? 1 : 2)))
  return false;

// We don't want to move around uses of condition values this late, so we
// check if it is legal to create the call to the intrinsic in the basic
// block containing the icmp.
if (Add->getParent() != Cmp->getParent() && !Add->hasOneUse())
  return false;

if (!replaceMathCmpWithIntrinsic(Add, A, B, Cmp,
                                 Intrinsic::uadd_with_overflow))
  return false;

// Reset callers - do not crash by iterating over a dead instruction.
ModifiedDT = ModifyDT::ModifyInstDT;
return true;
1616}

1618bool CodeGenPrepare::combineToUSubWithOverflow(CmpInst *Cmp,
                                             ModifyDT &ModifiedDT) {
// We are not expecting non-canonical/degenerate code. Just bail out.
Value *A = Cmp->getOperand(0), *B = Cmp->getOperand(1);
if (isa<Constant>(A) && isa<Constant>(B))
  return false;

// Convert (A u> B) to (A u< B) to simplify pattern matching.
ICmpInst::Predicate Pred = Cmp->getPredicate();
if (Pred == ICmpInst::ICMP_UGT) {
  std::swap(A, B);
  Pred = ICmpInst::ICMP_ULT;
}
// Convert special-case: (A == 0) is the same as (A u< 1).
if (Pred == ICmpInst::ICMP_EQ && match(B, m_ZeroInt())) {
  B = ConstantInt::get(B->getType(), 1);
  Pred = ICmpInst::ICMP_ULT;
}
// Convert special-case: (A != 0) is the same as (0 u< A).
if (Pred == ICmpInst::ICMP_NE && match(B, m_ZeroInt())) {
  std::swap(A, B);
  Pred = ICmpInst::ICMP_ULT;
}
if (Pred != ICmpInst::ICMP_ULT)
  return false;

// Walk the users of a variable operand of a compare looking for a subtract or
// add with that same operand. Also match the 2nd operand of the compare to
// the add/sub, but that may be a negated constant operand of an add.
Value *CmpVariableOperand = isa<Constant>(A) ? B : A;
BinaryOperator *Sub = nullptr;
for (User *U : CmpVariableOperand->users()) {
  // A - B, A u< B --> usubo(A, B)
  if (match(U, m_Sub(m_Specific(A), m_Specific(B)))) {
    Sub = cast<BinaryOperator>(U);
    break;
  }

  // A + (-C), A u< C (canonicalized form of (sub A, C))
  const APInt *CmpC, *AddC;
  if (match(U, m_Add(m_Specific(A), m_APInt(AddC))) &&
      match(B, m_APInt(CmpC)) && *AddC == -(*CmpC)) {
    Sub = cast<BinaryOperator>(U);
    break;
  }
}
if (!Sub)
  return false;

if (!TLI->shouldFormOverflowOp(ISD::USUBO,
                               TLI->getValueType(*DL, Sub->getType()),
                               Sub->hasNUsesOrMore(1)))
  return false;

if (!replaceMathCmpWithIntrinsic(Sub, Sub->getOperand(0), Sub->getOperand(1),
                                 Cmp, Intrinsic::usub_with_overflow))
  return false;

// Reset callers - do not crash by iterating over a dead instruction.
ModifiedDT = ModifyDT::ModifyInstDT;
return true;
1679}

1681/// Sink the given CmpInst into user blocks to reduce the number of virtual
1682/// registers that must be created and coalesced. This is a clear win except on
1683/// targets with multiple condition code registers (PowerPC), where it might
1684/// lose; some adjustment may be wanted there.
1685///
1686/// Return true if any changes are made.
1687static bool sinkCmpExpression(CmpInst *Cmp, const TargetLowering &TLI) {
if (TLI.hasMultipleConditionRegisters())
  return false;

// Avoid sinking soft-FP comparisons, since this can move them into a loop.
if (TLI.useSoftFloat() && isa<FCmpInst>(Cmp))
  return false;

// Only insert a cmp in each block once.
DenseMap<BasicBlock *, CmpInst *> InsertedCmps;

bool MadeChange = false;
for (Value::user_iterator UI = Cmp->user_begin(), E = Cmp->user_end();
     UI != E;) {
  Use &TheUse = UI.getUse();
  Instruction *User = cast<Instruction>(*UI);

  // Preincrement use iterator so we don't invalidate it.
  ++UI;

  // Don't bother for PHI nodes.
  if (isa<PHINode>(User))
    continue;

  // Figure out which BB this cmp is used in.
  BasicBlock *UserBB = User->getParent();
  BasicBlock *DefBB = Cmp->getParent();

  // If this user is in the same block as the cmp, don't change the cmp.
  if (UserBB == DefBB)
    continue;

  // If we have already inserted a cmp into this block, use it.
  CmpInst *&InsertedCmp = InsertedCmps[UserBB];

  if (!InsertedCmp) {
    BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
    assert(InsertPt != UserBB->end())(static_cast <bool> (InsertPt != UserBB->end()) ? void
 (0) : __assert_fail ("InsertPt != UserBB->end()", "llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 1724, __extension__ __PRETTY_FUNCTION__));
    InsertedCmp = CmpInst::Create(Cmp->getOpcode(), Cmp->getPredicate(),
                                  Cmp->getOperand(0), Cmp->getOperand(1), "",
                                  &*InsertPt);
    // Propagate the debug info.
    InsertedCmp->setDebugLoc(Cmp->getDebugLoc());
  }

  // Replace a use of the cmp with a use of the new cmp.
  TheUse = InsertedCmp;
  MadeChange = true;
  ++NumCmpUses;
}

// If we removed all uses, nuke the cmp.
if (Cmp->use_empty()) {
  Cmp->eraseFromParent();
  MadeChange = true;
}

return MadeChange;
1745}

1747/// For pattern like:
1748///
1749///   DomCond = icmp sgt/slt CmpOp0, CmpOp1 (might not be in DomBB)
1750///   ...
1751/// DomBB:
1752///   ...
1753///   br DomCond, TrueBB, CmpBB
1754/// CmpBB: (with DomBB being the single predecessor)
1755///   ...
1756///   Cmp = icmp eq CmpOp0, CmpOp1
1757///   ...
1758///
1759/// It would use two comparison on targets that lowering of icmp sgt/slt is
1760/// different from lowering of icmp eq (PowerPC). This function try to convert
1761/// 'Cmp = icmp eq CmpOp0, CmpOp1' to ' Cmp = icmp slt/sgt CmpOp0, CmpOp1'.
1762/// After that, DomCond and Cmp can use the same comparison so reduce one
1763/// comparison.
1764///
1765/// Return true if any changes are made.
1766static bool foldICmpWithDominatingICmp(CmpInst *Cmp,
                                     const TargetLowering &TLI) {
if (!EnableICMP_EQToICMP_ST && TLI.isEqualityCmpFoldedWithSignedCmp())
  return false;

ICmpInst::Predicate Pred = Cmp->getPredicate();
if (Pred != ICmpInst::ICMP_EQ)
  return false;

// If icmp eq has users other than BranchInst and SelectInst, converting it to
// icmp slt/sgt would introduce more redundant LLVM IR.
for (User *U : Cmp->users()) {
  if (isa<BranchInst>(U))
    continue;
  if (isa<SelectInst>(U) && cast<SelectInst>(U)->getCondition() == Cmp)
    continue;
  return false;
}

// This is a cheap/incomplete check for dominance - just match a single
// predecessor with a conditional branch.
BasicBlock *CmpBB = Cmp->getParent();
BasicBlock *DomBB = CmpBB->getSinglePredecessor();
if (!DomBB)
  return false;

// We want to ensure that the only way control gets to the comparison of
// interest is that a less/greater than comparison on the same operands is
// false.
Value *DomCond;
BasicBlock *TrueBB, *FalseBB;
if (!match(DomBB->getTerminator(), m_Br(m_Value(DomCond), TrueBB, FalseBB)))
  return false;
if (CmpBB != FalseBB)
  return false;

Value *CmpOp0 = Cmp->getOperand(0), *CmpOp1 = Cmp->getOperand(1);
ICmpInst::Predicate DomPred;
if (!match(DomCond, m_ICmp(DomPred, m_Specific(CmpOp0), m_Specific(CmpOp1))))
  return false;
if (DomPred != ICmpInst::ICMP_SGT && DomPred != ICmpInst::ICMP_SLT)
  return false;

// Convert the equality comparison to the opposite of the dominating
// comparison and swap the direction for all branch/select users.
// We have conceptually converted:
// Res = (a < b) ? <LT_RES> : (a == b) ? <EQ_RES> : <GT_RES>;
// to
// Res = (a < b) ? <LT_RES> : (a > b)  ? <GT_RES> : <EQ_RES>;
// And similarly for branches.
for (User *U : Cmp->users()) {
  if (auto *BI = dyn_cast<BranchInst>(U)) {
    assert(BI->isConditional() && "Must be conditional")(static_cast <bool> (BI->isConditional() && "Must be conditional"
) ? void (0) : __assert_fail ("BI->isConditional() && \"Must be conditional\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1818, __extension__ __PRETTY_FUNCTION__
));
    BI->swapSuccessors();
    continue;
  }
  if (auto *SI = dyn_cast<SelectInst>(U)) {
    // Swap operands
    SI->swapValues();
    SI->swapProfMetadata();
    continue;
  }
  llvm_unreachable("Must be a branch or a select")::llvm::llvm_unreachable_internal("Must be a branch or a select"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1828);
}
Cmp->setPredicate(CmpInst::getSwappedPredicate(DomPred));
return true;
1832}

1834bool CodeGenPrepare::optimizeCmp(CmpInst *Cmp, ModifyDT &ModifiedDT) {
if (sinkCmpExpression(Cmp, *TLI))
  return true;

if (combineToUAddWithOverflow(Cmp, ModifiedDT))
  return true;

if (combineToUSubWithOverflow(Cmp, ModifiedDT))
  return true;

if (foldICmpWithDominatingICmp(Cmp, *TLI))
  return true;

return false;
1848}

1850/// Duplicate and sink the given 'and' instruction into user blocks where it is
1851/// used in a compare to allow isel to generate better code for targets where
1852/// this operation can be combined.
1853///
1854/// Return true if any changes are made.
1855static bool sinkAndCmp0Expression(Instruction *AndI, const TargetLowering &TLI,
                                SetOfInstrs &InsertedInsts) {
// Double-check that we're not trying to optimize an instruction that was
// already optimized by some other part of this pass.
assert(!InsertedInsts.count(AndI) &&(static_cast <bool> (!InsertedInsts.count(AndI) &&
 "Attempting to optimize already optimized and instruction") ?
 void (0) : __assert_fail ("!InsertedInsts.count(AndI) && \"Attempting to optimize already optimized and instruction\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1860, __extension__ __PRETTY_FUNCTION__
))
       "Attempting to optimize already optimized and instruction")(static_cast <bool> (!InsertedInsts.count(AndI) &&
 "Attempting to optimize already optimized and instruction") ?
 void (0) : __assert_fail ("!InsertedInsts.count(AndI) && \"Attempting to optimize already optimized and instruction\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1860, __extension__ __PRETTY_FUNCTION__
));
(void)InsertedInsts;

// Nothing to do for single use in same basic block.
if (AndI->hasOneUse() &&
    AndI->getParent() == cast<Instruction>(*AndI->user_begin())->getParent())
  return false;

// Try to avoid cases where sinking/duplicating is likely to increase register
// pressure.
if (!isa<ConstantInt>(AndI->getOperand(0)) &&
    !isa<ConstantInt>(AndI->getOperand(1)) &&
    AndI->getOperand(0)->hasOneUse() && AndI->getOperand(1)->hasOneUse())
  return false;

for (auto *U : AndI->users()) {
  Instruction *User = cast<Instruction>(U);

  // Only sink 'and' feeding icmp with 0.
  if (!isa<ICmpInst>(User))
    return false;

  auto *CmpC = dyn_cast<ConstantInt>(User->getOperand(1));
  if (!CmpC || !CmpC->isZero())
    return false;
}

if (!TLI.isMaskAndCmp0FoldingBeneficial(*AndI))
  return false;

LLVM_DEBUG(dbgs() << "found 'and' feeding only icmp 0;\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "found 'and' feeding only icmp 0;\n"
; } } while (false);
LLVM_DEBUG(AndI->getParent()->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { AndI->getParent()->dump(); } } while
 (false);

// Push the 'and' into the same block as the icmp 0.  There should only be
// one (icmp (and, 0)) in each block, since CSE/GVN should have removed any
// others, so we don't need to keep track of which BBs we insert into.
for (Value::user_iterator UI = AndI->user_begin(), E = AndI->user_end();
     UI != E;) {
  Use &TheUse = UI.getUse();
  Instruction *User = cast<Instruction>(*UI);

  // Preincrement use iterator so we don't invalidate it.
  ++UI;

  LLVM_DEBUG(dbgs() << "sinking 'and' use: " << *User << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "sinking 'and' use: " <<
 *User << "\n"; } } while (false);

  // Keep the 'and' in the same place if the use is already in the same block.
  Instruction *InsertPt =
      User->getParent() == AndI->getParent() ? AndI : User;
  Instruction *InsertedAnd =
      BinaryOperator::Create(Instruction::And, AndI->getOperand(0),
                             AndI->getOperand(1), "", InsertPt);
  // Propagate the debug info.
  InsertedAnd->setDebugLoc(AndI->getDebugLoc());

  // Replace a use of the 'and' with a use of the new 'and'.
  TheUse = InsertedAnd;
  ++NumAndUses;
  LLVM_DEBUG(User->getParent()->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { User->getParent()->dump(); } } while
 (false);
}

// We removed all uses, nuke the and.
AndI->eraseFromParent();
return true;
1924}

1926/// Check if the candidates could be combined with a shift instruction, which
1927/// includes:
1928/// 1. Truncate instruction
1929/// 2. And instruction and the imm is a mask of the low bits:
1930/// imm & (imm+1) == 0
1931static bool isExtractBitsCandidateUse(Instruction *User) {
if (!isa<TruncInst>(User)) {
  if (User->getOpcode() != Instruction::And ||
      !isa<ConstantInt>(User->getOperand(1)))
    return false;

  const APInt &Cimm = cast<ConstantInt>(User->getOperand(1))->getValue();

  if ((Cimm & (Cimm + 1)).getBoolValue())
    return false;
}
return true;
1943}

1945/// Sink both shift and truncate instruction to the use of truncate's BB.
1946static bool
1947SinkShiftAndTruncate(BinaryOperator *ShiftI, Instruction *User, ConstantInt *CI,
                   DenseMap<BasicBlock *, BinaryOperator *> &InsertedShifts,
                   const TargetLowering &TLI, const DataLayout &DL) {
BasicBlock *UserBB = User->getParent();
DenseMap<BasicBlock *, CastInst *> InsertedTruncs;
auto *TruncI = cast<TruncInst>(User);
bool MadeChange = false;

for (Value::user_iterator TruncUI = TruncI->user_begin(),
                          TruncE = TruncI->user_end();
     TruncUI != TruncE;) {

  Use &TruncTheUse = TruncUI.getUse();
  Instruction *TruncUser = cast<Instruction>(*TruncUI);
  // Preincrement use iterator so we don't invalidate it.

  ++TruncUI;

  int ISDOpcode = TLI.InstructionOpcodeToISD(TruncUser->getOpcode());
  if (!ISDOpcode)
    continue;

  // If the use is actually a legal node, there will not be an
  // implicit truncate.
  // FIXME: always querying the result type is just an
  // approximation; some nodes' legality is determined by the
  // operand or other means. There's no good way to find out though.
  if (TLI.isOperationLegalOrCustom(
          ISDOpcode, TLI.getValueType(DL, TruncUser->getType(), true)))
    continue;

  // Don't bother for PHI nodes.
  if (isa<PHINode>(TruncUser))
    continue;

  BasicBlock *TruncUserBB = TruncUser->getParent();

  if (UserBB == TruncUserBB)
    continue;

  BinaryOperator *&InsertedShift = InsertedShifts[TruncUserBB];
  CastInst *&InsertedTrunc = InsertedTruncs[TruncUserBB];

  if (!InsertedShift && !InsertedTrunc) {
    BasicBlock::iterator InsertPt = TruncUserBB->getFirstInsertionPt();
    assert(InsertPt != TruncUserBB->end())(static_cast <bool> (InsertPt != TruncUserBB->end())
 ? void (0) : __assert_fail ("InsertPt != TruncUserBB->end()"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 1992, __extension__ __PRETTY_FUNCTION__
));
    // Sink the shift
    if (ShiftI->getOpcode() == Instruction::AShr)
      InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
                                                 "", &*InsertPt);
    else
      InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
                                                 "", &*InsertPt);
    InsertedShift->setDebugLoc(ShiftI->getDebugLoc());

    // Sink the trunc
    BasicBlock::iterator TruncInsertPt = TruncUserBB->getFirstInsertionPt();
    TruncInsertPt++;
    assert(TruncInsertPt != TruncUserBB->end())(static_cast <bool> (TruncInsertPt != TruncUserBB->end
()) ? void (0) : __assert_fail ("TruncInsertPt != TruncUserBB->end()"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 2005, __extension__ __PRETTY_FUNCTION__
));

    InsertedTrunc = CastInst::Create(TruncI->getOpcode(), InsertedShift,
                                     TruncI->getType(), "", &*TruncInsertPt);
    InsertedTrunc->setDebugLoc(TruncI->getDebugLoc());

    MadeChange = true;

    TruncTheUse = InsertedTrunc;
  }
}
return MadeChange;
2017}

2019/// Sink the shift *right* instruction into user blocks if the uses could
2020/// potentially be combined with this shift instruction and generate BitExtract
2021/// instruction. It will only be applied if the architecture supports BitExtract
2022/// instruction. Here is an example:
2023/// BB1:
2024///   %x.extract.shift = lshr i64 %arg1, 32
2025/// BB2:
2026///   %x.extract.trunc = trunc i64 %x.extract.shift to i16
2027/// ==>
2028///
2029/// BB2:
2030///   %x.extract.shift.1 = lshr i64 %arg1, 32
2031///   %x.extract.trunc = trunc i64 %x.extract.shift.1 to i16
2032///
2033/// CodeGen will recognize the pattern in BB2 and generate BitExtract
2034/// instruction.
2035/// Return true if any changes are made.
2036static bool OptimizeExtractBits(BinaryOperator *ShiftI, ConstantInt *CI,
                              const TargetLowering &TLI,
                              const DataLayout &DL) {
BasicBlock *DefBB = ShiftI->getParent();

/// Only insert instructions in each block once.
DenseMap<BasicBlock *, BinaryOperator *> InsertedShifts;

bool shiftIsLegal = TLI.isTypeLegal(TLI.getValueType(DL, ShiftI->getType()));

bool MadeChange = false;
for (Value::user_iterator UI = ShiftI->user_begin(), E = ShiftI->user_end();
     UI != E;) {
  Use &TheUse = UI.getUse();
  Instruction *User = cast<Instruction>(*UI);
  // Preincrement use iterator so we don't invalidate it.
  ++UI;

  // Don't bother for PHI nodes.
  if (isa<PHINode>(User))
    continue;

  if (!isExtractBitsCandidateUse(User))
    continue;

  BasicBlock *UserBB = User->getParent();

  if (UserBB == DefBB) {
    // If the shift and truncate instruction are in the same BB. The use of
    // the truncate(TruncUse) may still introduce another truncate if not
    // legal. In this case, we would like to sink both shift and truncate
    // instruction to the BB of TruncUse.
    // for example:
    // BB1:
    // i64 shift.result = lshr i64 opnd, imm
    // trunc.result = trunc shift.result to i16
    //
    // BB2:
    //   ----> We will have an implicit truncate here if the architecture does
    //   not have i16 compare.
    // cmp i16 trunc.result, opnd2
    //
    if (isa<TruncInst>(User) &&
        shiftIsLegal
        // If the type of the truncate is legal, no truncate will be
        // introduced in other basic blocks.
        && (!TLI.isTypeLegal(TLI.getValueType(DL, User->getType()))))
      MadeChange =
          SinkShiftAndTruncate(ShiftI, User, CI, InsertedShifts, TLI, DL);

    continue;
  }
  // If we have already inserted a shift into this block, use it.
  BinaryOperator *&InsertedShift = InsertedShifts[UserBB];

  if (!InsertedShift) {
    BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
    assert(InsertPt != UserBB->end())(static_cast <bool> (InsertPt != UserBB->end()) ? void
 (0) : __assert_fail ("InsertPt != UserBB->end()", "llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2093, __extension__ __PRETTY_FUNCTION__));

    if (ShiftI->getOpcode() == Instruction::AShr)
      InsertedShift = BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI,
                                                 "", &*InsertPt);
    else
      InsertedShift = BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI,
                                                 "", &*InsertPt);
    InsertedShift->setDebugLoc(ShiftI->getDebugLoc());

    MadeChange = true;
  }

  // Replace a use of the shift with a use of the new shift.
  TheUse = InsertedShift;
}

// If we removed all uses, or there are none, nuke the shift.
if (ShiftI->use_empty()) {
  salvageDebugInfo(*ShiftI);
  ShiftI->eraseFromParent();
  MadeChange = true;
}

return MadeChange;
2118}

2120/// If counting leading or trailing zeros is an expensive operation and a zero
2121/// input is defined, add a check for zero to avoid calling the intrinsic.
2122///
2123/// We want to transform:
2124///     %z = call i64 @llvm.cttz.i64(i64 %A, i1 false)
2125///
2126/// into:
2127///   entry:
2128///     %cmpz = icmp eq i64 %A, 0
2129///     br i1 %cmpz, label %cond.end, label %cond.false
2130///   cond.false:
2131///     %z = call i64 @llvm.cttz.i64(i64 %A, i1 true)
2132///     br label %cond.end
2133///   cond.end:
2134///     %ctz = phi i64 [ 64, %entry ], [ %z, %cond.false ]
2135///
2136/// If the transform is performed, return true and set ModifiedDT to true.
2137static bool despeculateCountZeros(IntrinsicInst *CountZeros,
                                const TargetLowering *TLI,
                                const DataLayout *DL, ModifyDT &ModifiedDT,
                                SmallSet<BasicBlock *, 32> &FreshBBs,
                                bool IsHugeFunc) {
// If a zero input is undefined, it doesn't make sense to despeculate that.
if (match(CountZeros->getOperand(1), m_One()))
  return false;

// If it's cheap to speculate, there's nothing to do.
Type *Ty = CountZeros->getType();
auto IntrinsicID = CountZeros->getIntrinsicID();
if ((IntrinsicID == Intrinsic::cttz && TLI->isCheapToSpeculateCttz(Ty)) ||
    (IntrinsicID == Intrinsic::ctlz && TLI->isCheapToSpeculateCtlz(Ty)))
  return false;

// Only handle legal scalar cases. Anything else requires too much work.
unsigned SizeInBits = Ty->getScalarSizeInBits();
if (Ty->isVectorTy() || SizeInBits > DL->getLargestLegalIntTypeSizeInBits())
  return false;

// Bail if the value is never zero.
Use &Op = CountZeros->getOperandUse(0);
if (isKnownNonZero(Op, *DL))
  return false;

// The intrinsic will be sunk behind a compare against zero and branch.
BasicBlock *StartBlock = CountZeros->getParent();
BasicBlock *CallBlock = StartBlock->splitBasicBlock(CountZeros, "cond.false");
if (IsHugeFunc)
  FreshBBs.insert(CallBlock);

// Create another block after the count zero intrinsic. A PHI will be added
// in this block to select the result of the intrinsic or the bit-width
// constant if the input to the intrinsic is zero.
BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(CountZeros));
BasicBlock *EndBlock = CallBlock->splitBasicBlock(SplitPt, "cond.end");
if (IsHugeFunc)
  FreshBBs.insert(EndBlock);

// Set up a builder to create a compare, conditional branch, and PHI.
IRBuilder<> Builder(CountZeros->getContext());
Builder.SetInsertPoint(StartBlock->getTerminator());
Builder.SetCurrentDebugLocation(CountZeros->getDebugLoc());

// Replace the unconditional branch that was created by the first split with
// a compare against zero and a conditional branch.
Value *Zero = Constant::getNullValue(Ty);
// Avoid introducing branch on poison. This also replaces the ctz operand.
if (!isGuaranteedNotToBeUndefOrPoison(Op))
  Op = Builder.CreateFreeze(Op, Op->getName() + ".fr");
Value *Cmp = Builder.CreateICmpEQ(Op, Zero, "cmpz");
Builder.CreateCondBr(Cmp, EndBlock, CallBlock);
StartBlock->getTerminator()->eraseFromParent();

// Create a PHI in the end block to select either the output of the intrinsic
// or the bit width of the operand.
Builder.SetInsertPoint(&EndBlock->front());
PHINode *PN = Builder.CreatePHI(Ty, 2, "ctz");
replaceAllUsesWith(CountZeros, PN, FreshBBs, IsHugeFunc);
Value *BitWidth = Builder.getInt(APInt(SizeInBits, SizeInBits));
PN->addIncoming(BitWidth, StartBlock);
PN->addIncoming(CountZeros, CallBlock);

// We are explicitly handling the zero case, so we can set the intrinsic's
// undefined zero argument to 'true'. This will also prevent reprocessing the
// intrinsic; we only despeculate when a zero input is defined.
CountZeros->setArgOperand(1, Builder.getTrue());
ModifiedDT = ModifyDT::ModifyBBDT;
return true;
2207}

2209bool CodeGenPrepare::optimizeCallInst(CallInst *CI, ModifyDT &ModifiedDT) {
BasicBlock *BB = CI->getParent();

// Lower inline assembly if we can.
// If we found an inline asm expession, and if the target knows how to
// lower it to normal LLVM code, do so now.
if (CI->isInlineAsm()) {
  if (TLI->ExpandInlineAsm(CI)) {
    // Avoid invalidating the iterator.
    CurInstIterator = BB->begin();
    // Avoid processing instructions out of order, which could cause
    // reuse before a value is defined.
    SunkAddrs.clear();
    return true;
  }
  // Sink address computing for memory operands into the block.
  if (optimizeInlineAsmInst(CI))
    return true;
}

// Align the pointer arguments to this call if the target thinks it's a good
// idea
unsigned MinSize;
Align PrefAlign;
if (TLI->shouldAlignPointerArgs(CI, MinSize, PrefAlign)) {
  for (auto &Arg : CI->args()) {
    // We want to align both objects whose address is used directly and
    // objects whose address is used in casts and GEPs, though it only makes
    // sense for GEPs if the offset is a multiple of the desired alignment and
    // if size - offset meets the size threshold.
    if (!Arg->getType()->isPointerTy())
      continue;
    APInt Offset(DL->getIndexSizeInBits(
                     cast<PointerType>(Arg->getType())->getAddressSpace()),
                 0);
    Value *Val = Arg->stripAndAccumulateInBoundsConstantOffsets(*DL, Offset);
    uint64_t Offset2 = Offset.getLimitedValue();
    if (!isAligned(PrefAlign, Offset2))
      continue;
    AllocaInst *AI;
    if ((AI = dyn_cast<AllocaInst>(Val)) && AI->getAlign() < PrefAlign &&
        DL->getTypeAllocSize(AI->getAllocatedType()) >= MinSize + Offset2)
      AI->setAlignment(PrefAlign);
    // Global variables can only be aligned if they are defined in this
    // object (i.e. they are uniquely initialized in this object), and
    // over-aligning global variables that have an explicit section is
    // forbidden.
    GlobalVariable *GV;
    if ((GV = dyn_cast<GlobalVariable>(Val)) && GV->canIncreaseAlignment() &&
        GV->getPointerAlignment(*DL) < PrefAlign &&
        DL->getTypeAllocSize(GV->getValueType()) >= MinSize + Offset2)
      GV->setAlignment(PrefAlign);
  }
}
// If this is a memcpy (or similar) then we may be able to improve the
// alignment.
if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(CI)) {
  Align DestAlign = getKnownAlignment(MI->getDest(), *DL);
  MaybeAlign MIDestAlign = MI->getDestAlign();
  if (!MIDestAlign || DestAlign > *MIDestAlign)
    MI->setDestAlignment(DestAlign);
  if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI)) {
    MaybeAlign MTISrcAlign = MTI->getSourceAlign();
    Align SrcAlign = getKnownAlignment(MTI->getSource(), *DL);
    if (!MTISrcAlign || SrcAlign > *MTISrcAlign)
      MTI->setSourceAlignment(SrcAlign);
  }
}

// If we have a cold call site, try to sink addressing computation into the
// cold block.  This interacts with our handling for loads and stores to
// ensure that we can fold all uses of a potential addressing computation
// into their uses.  TODO: generalize this to work over profiling data
if (CI->hasFnAttr(Attribute::Cold) && !OptSize &&
    !llvm::shouldOptimizeForSize(BB, PSI, BFI.get()))
  for (auto &Arg : CI->args()) {
    if (!Arg->getType()->isPointerTy())
      continue;
    unsigned AS = Arg->getType()->getPointerAddressSpace();
    if (optimizeMemoryInst(CI, Arg, Arg->getType(), AS))
      return true;
  }

IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI);
if (II) {
  switch (II->getIntrinsicID()) {
  default:
    break;
  case Intrinsic::assume:
    llvm_unreachable("llvm.assume should have been removed already")::llvm::llvm_unreachable_internal("llvm.assume should have been removed already"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 2298);
  case Intrinsic::experimental_widenable_condition: {
    // Give up on future widening oppurtunties so that we can fold away dead
    // paths and merge blocks before going into block-local instruction
    // selection.
    if (II->use_empty()) {
      II->eraseFromParent();
      return true;
    }
    Constant *RetVal = ConstantInt::getTrue(II->getContext());
    resetIteratorIfInvalidatedWhileCalling(BB, [&]() {
      replaceAndRecursivelySimplify(CI, RetVal, TLInfo, nullptr);
    });
    return true;
  }
  case Intrinsic::objectsize:
    llvm_unreachable("llvm.objectsize.* should have been lowered already")::llvm::llvm_unreachable_internal("llvm.objectsize.* should have been lowered already"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 2314);
  case Intrinsic::is_constant:
    llvm_unreachable("llvm.is.constant.* should have been lowered already")::llvm::llvm_unreachable_internal("llvm.is.constant.* should have been lowered already"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 2316);
  case Intrinsic::aarch64_stlxr:
  case Intrinsic::aarch64_stxr: {
    ZExtInst *ExtVal = dyn_cast<ZExtInst>(CI->getArgOperand(0));
    if (!ExtVal || !ExtVal->hasOneUse() ||
        ExtVal->getParent() == CI->getParent())
      return false;
    // Sink a zext feeding stlxr/stxr before it, so it can be folded into it.
    ExtVal->moveBefore(CI);
    // Mark this instruction as "inserted by CGP", so that other
    // optimizations don't touch it.
    InsertedInsts.insert(ExtVal);
    return true;
  }

  case Intrinsic::launder_invariant_group:
  case Intrinsic::strip_invariant_group: {
    Value *ArgVal = II->getArgOperand(0);
    auto it = LargeOffsetGEPMap.find(II);
    if (it != LargeOffsetGEPMap.end()) {
      // Merge entries in LargeOffsetGEPMap to reflect the RAUW.
      // Make sure not to have to deal with iterator invalidation
      // after possibly adding ArgVal to LargeOffsetGEPMap.
      auto GEPs = std::move(it->second);
      LargeOffsetGEPMap[ArgVal].append(GEPs.begin(), GEPs.end());
      LargeOffsetGEPMap.erase(II);
    }

    replaceAllUsesWith(II, ArgVal, FreshBBs, IsHugeFunc);
    II->eraseFromParent();
    return true;
  }
  case Intrinsic::cttz:
  case Intrinsic::ctlz:
    // If counting zeros is expensive, try to avoid it.
    return despeculateCountZeros(II, TLI, DL, ModifiedDT, FreshBBs,
                                 IsHugeFunc);
  case Intrinsic::fshl:
  case Intrinsic::fshr:
    return optimizeFunnelShift(II);
  case Intrinsic::dbg_assign:
  case Intrinsic::dbg_value:
    return fixupDbgValue(II);
  case Intrinsic::masked_gather:
    return optimizeGatherScatterInst(II, II->getArgOperand(0));
  case Intrinsic::masked_scatter:
    return optimizeGatherScatterInst(II, II->getArgOperand(1));
  }

  SmallVector<Value *, 2> PtrOps;
  Type *AccessTy;
  if (TLI->getAddrModeArguments(II, PtrOps, AccessTy))
    while (!PtrOps.empty()) {
      Value *PtrVal = PtrOps.pop_back_val();
      unsigned AS = PtrVal->getType()->getPointerAddressSpace();
      if (optimizeMemoryInst(II, PtrVal, AccessTy, AS))
        return true;
    }
}

// From here on out we're working with named functions.
if (!CI->getCalledFunction())
  return false;

// Lower all default uses of _chk calls.  This is very similar
// to what InstCombineCalls does, but here we are only lowering calls
// to fortified library functions (e.g. __memcpy_chk) that have the default
// "don't know" as the objectsize.  Anything else should be left alone.
FortifiedLibCallSimplifier Simplifier(TLInfo, true);
IRBuilder<> Builder(CI);
if (Value *V = Simplifier.optimizeCall(CI, Builder)) {
  replaceAllUsesWith(CI, V, FreshBBs, IsHugeFunc);
  CI->eraseFromParent();
  return true;
}

return false;
2393}

2395/// Look for opportunities to duplicate return instructions to the predecessor
2396/// to enable tail call optimizations. The case it is currently looking for is:
2397/// @code
2398/// bb0:
2399///   %tmp0 = tail call i32 @f0()
2400///   br label %return
2401/// bb1:
2402///   %tmp1 = tail call i32 @f1()
2403///   br label %return
2404/// bb2:
2405///   %tmp2 = tail call i32 @f2()
2406///   br label %return
2407/// return:
2408///   %retval = phi i32 [ %tmp0, %bb0 ], [ %tmp1, %bb1 ], [ %tmp2, %bb2 ]
2409///   ret i32 %retval
2410/// @endcode
2411///
2412/// =>
2413///
2414/// @code
2415/// bb0:
2416///   %tmp0 = tail call i32 @f0()
2417///   ret i32 %tmp0
2418/// bb1:
2419///   %tmp1 = tail call i32 @f1()
2420///   ret i32 %tmp1
2421/// bb2:
2422///   %tmp2 = tail call i32 @f2()
2423///   ret i32 %tmp2
2424/// @endcode
2425bool CodeGenPrepare::dupRetToEnableTailCallOpts(BasicBlock *BB,
                                              ModifyDT &ModifiedDT) {
if (!BB->getTerminator())
  return false;

ReturnInst *RetI = dyn_cast<ReturnInst>(BB->getTerminator());
if (!RetI)
  return false;

PHINode *PN = nullptr;
ExtractValueInst *EVI = nullptr;
BitCastInst *BCI = nullptr;
Value *V = RetI->getReturnValue();
if (V) {
  BCI = dyn_cast<BitCastInst>(V);
  if (BCI)
    V = BCI->getOperand(0);

  EVI = dyn_cast<ExtractValueInst>(V);
  if (EVI) {
    V = EVI->getOperand(0);
    if (!llvm::all_of(EVI->indices(), [](unsigned idx) { return idx == 0; }))
      return false;
  }

  PN = dyn_cast<PHINode>(V);
  if (!PN)
    return false;
}

if (PN && PN->getParent() != BB)
  return false;

auto isLifetimeEndOrBitCastFor = [](const Instruction *Inst) {
  const BitCastInst *BC = dyn_cast<BitCastInst>(Inst);
  if (BC && BC->hasOneUse())
    Inst = BC->user_back();

  if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst))
    return II->getIntrinsicID() == Intrinsic::lifetime_end;
  return false;
};

// Make sure there are no instructions between the first instruction
// and return.
const Instruction *BI = BB->getFirstNonPHI();
// Skip over debug and the bitcast.
while (isa<DbgInfoIntrinsic>(BI) || BI == BCI || BI == EVI ||
       isa<PseudoProbeInst>(BI) || isLifetimeEndOrBitCastFor(BI))
  BI = BI->getNextNode();
if (BI != RetI)
  return false;

/// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail
/// call.
const Function *F = BB->getParent();
SmallVector<BasicBlock *, 4> TailCallBBs;
if (PN) {
  for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
    // Look through bitcasts.
    Value *IncomingVal = PN->getIncomingValue(I)->stripPointerCasts();
    CallInst *CI = dyn_cast<CallInst>(IncomingVal);
    BasicBlock *PredBB = PN->getIncomingBlock(I);
    // Make sure the phi value is indeed produced by the tail call.
    if (CI && CI->hasOneUse() && CI->getParent() == PredBB &&
        TLI->mayBeEmittedAsTailCall(CI) &&
        attributesPermitTailCall(F, CI, RetI, *TLI))
      TailCallBBs.push_back(PredBB);
  }
} else {
  SmallPtrSet<BasicBlock *, 4> VisitedBBs;
  for (BasicBlock *Pred : predecessors(BB)) {
    if (!VisitedBBs.insert(Pred).second)
      continue;
    if (Instruction *I = Pred->rbegin()->getPrevNonDebugInstruction(true)) {
      CallInst *CI = dyn_cast<CallInst>(I);
      if (CI && CI->use_empty() && TLI->mayBeEmittedAsTailCall(CI) &&
          attributesPermitTailCall(F, CI, RetI, *TLI))
        TailCallBBs.push_back(Pred);
    }
  }
}

bool Changed = false;
for (auto const &TailCallBB : TailCallBBs) {
  // Make sure the call instruction is followed by an unconditional branch to
  // the return block.
  BranchInst *BI = dyn_cast<BranchInst>(TailCallBB->getTerminator());
  if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB)
    continue;

  // Duplicate the return into TailCallBB.
  (void)FoldReturnIntoUncondBranch(RetI, BB, TailCallBB);
  assert(!VerifyBFIUpdates ||(static_cast <bool> (!VerifyBFIUpdates || BFI->getBlockFreq
(BB) >= BFI->getBlockFreq(TailCallBB)) ? void (0) : __assert_fail
 ("!VerifyBFIUpdates || BFI->getBlockFreq(BB) >= BFI->getBlockFreq(TailCallBB)"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 2519, __extension__ __PRETTY_FUNCTION__
))
         BFI->getBlockFreq(BB) >= BFI->getBlockFreq(TailCallBB))(static_cast <bool> (!VerifyBFIUpdates || BFI->getBlockFreq
(BB) >= BFI->getBlockFreq(TailCallBB)) ? void (0) : __assert_fail
 ("!VerifyBFIUpdates || BFI->getBlockFreq(BB) >= BFI->getBlockFreq(TailCallBB)"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 2519, __extension__ __PRETTY_FUNCTION__
));
  BFI->setBlockFreq(
      BB,
      (BFI->getBlockFreq(BB) - BFI->getBlockFreq(TailCallBB)).getFrequency());
  ModifiedDT = ModifyDT::ModifyBBDT;
  Changed = true;
  ++NumRetsDup;
}

// If we eliminated all predecessors of the block, delete the block now.
if (Changed && !BB->hasAddressTaken() && pred_empty(BB))
  BB->eraseFromParent();

return Changed;
2533}

2535//===----------------------------------------------------------------------===//
2536// Memory Optimization
2537//===----------------------------------------------------------------------===//

2539namespace {

2541/// This is an extended version of TargetLowering::AddrMode
2542/// which holds actual Value*'s for register values.
2543struct ExtAddrMode : public TargetLowering::AddrMode {
Value *BaseReg = nullptr;
Value *ScaledReg = nullptr;
Value *OriginalValue = nullptr;
bool InBounds = true;

enum FieldName {
  NoField = 0x00,
  BaseRegField = 0x01,
  BaseGVField = 0x02,
  BaseOffsField = 0x04,
  ScaledRegField = 0x08,
  ScaleField = 0x10,
  MultipleFields = 0xff
};

ExtAddrMode() = default;

void print(raw_ostream &OS) const;
void dump() const;

FieldName compare(const ExtAddrMode &other) {
  // First check that the types are the same on each field, as differing types
  // is something we can't cope with later on.
  if (BaseReg && other.BaseReg &&
      BaseReg->getType() != other.BaseReg->getType())
    return MultipleFields;
  if (BaseGV && other.BaseGV && BaseGV->getType() != other.BaseGV->getType())
    return MultipleFields;
  if (ScaledReg && other.ScaledReg &&
      ScaledReg->getType() != other.ScaledReg->getType())
    return MultipleFields;

  // Conservatively reject 'inbounds' mismatches.
  if (InBounds != other.InBounds)
    return MultipleFields;

  // Check each field to see if it differs.
  unsigned Result = NoField;
  if (BaseReg != other.BaseReg)
    Result |= BaseRegField;
  if (BaseGV != other.BaseGV)
    Result |= BaseGVField;
  if (BaseOffs != other.BaseOffs)
    Result |= BaseOffsField;
  if (ScaledReg != other.ScaledReg)
    Result |= ScaledRegField;
  // Don't count 0 as being a different scale, because that actually means
  // unscaled (which will already be counted by having no ScaledReg).
  if (Scale && other.Scale && Scale != other.Scale)
    Result |= ScaleField;

  if (llvm::popcount(Result) > 1)
    return MultipleFields;
  else
    return static_cast<FieldName>(Result);
}

// An AddrMode is trivial if it involves no calculation i.e. it is just a base
// with no offset.
bool isTrivial() {
  // An AddrMode is (BaseGV + BaseReg + BaseOffs + ScaleReg * Scale) so it is
  // trivial if at most one of these terms is nonzero, except that BaseGV and
  // BaseReg both being zero actually means a null pointer value, which we
  // consider to be 'non-zero' here.
  return !BaseOffs && !Scale && !(BaseGV && BaseReg);
}

Value *GetFieldAsValue(FieldName Field, Type *IntPtrTy) {
  switch (Field) {
  default:
    return nullptr;
  case BaseRegField:
    return BaseReg;
  case BaseGVField:
    return BaseGV;
  case ScaledRegField:
    return ScaledReg;
  case BaseOffsField:
    return ConstantInt::get(IntPtrTy, BaseOffs);
  }
}

void SetCombinedField(FieldName Field, Value *V,
                      const SmallVectorImpl<ExtAddrMode> &AddrModes) {
  switch (Field) {
  default:
    llvm_unreachable("Unhandled fields are expected to be rejected earlier")::llvm::llvm_unreachable_internal("Unhandled fields are expected to be rejected earlier"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 2630);
    break;
  case ExtAddrMode::BaseRegField:
    BaseReg = V;
    break;
  case ExtAddrMode::BaseGVField:
    // A combined BaseGV is an Instruction, not a GlobalValue, so it goes
    // in the BaseReg field.
    assert(BaseReg == nullptr)(static_cast <bool> (BaseReg == nullptr) ? void (0) : __assert_fail
 ("BaseReg == nullptr", "llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2638, __extension__ __PRETTY_FUNCTION__));
    BaseReg = V;
    BaseGV = nullptr;
    break;
  case ExtAddrMode::ScaledRegField:
    ScaledReg = V;
    // If we have a mix of scaled and unscaled addrmodes then we want scale
    // to be the scale and not zero.
    if (!Scale)
      for (const ExtAddrMode &AM : AddrModes)
        if (AM.Scale) {
          Scale = AM.Scale;
          break;
        }
    break;
  case ExtAddrMode::BaseOffsField:
    // The offset is no longer a constant, so it goes in ScaledReg with a
    // scale of 1.
    assert(ScaledReg == nullptr)(static_cast <bool> (ScaledReg == nullptr) ? void (0) :
 __assert_fail ("ScaledReg == nullptr", "llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 2656, __extension__ __PRETTY_FUNCTION__));
    ScaledReg = V;
    Scale = 1;
    BaseOffs = 0;
    break;
  }
}
2663};

2665#ifndef NDEBUG
2666static inline raw_ostream &operator<<(raw_ostream &OS, const ExtAddrMode &AM) {
AM.print(OS);
return OS;
2669}
2670#endif

2672#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
2673void ExtAddrMode::print(raw_ostream &OS) const {
bool NeedPlus = false;
OS << "[";
if (InBounds)
  OS << "inbounds ";
if (BaseGV) {
  OS << "GV:";
  BaseGV->printAsOperand(OS, /*PrintType=*/false);
  NeedPlus = true;
}

if (BaseOffs) {
  OS << (NeedPlus ? " + " : "") << BaseOffs;
  NeedPlus = true;
}

if (BaseReg) {
  OS << (NeedPlus ? " + " : "") << "Base:";
  BaseReg->printAsOperand(OS, /*PrintType=*/false);
  NeedPlus = true;
}
if (Scale) {
  OS << (NeedPlus ? " + " : "") << Scale << "*";
  ScaledReg->printAsOperand(OS, /*PrintType=*/false);
}

OS << ']';
2700}

2702LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void ExtAddrMode::dump() const {
print(dbgs());
dbgs() << '\n';
2705}
2706#endif

2708} // end anonymous namespace

2710namespace {

2712/// This class provides transaction based operation on the IR.
2713/// Every change made through this class is recorded in the internal state and
2714/// can be undone (rollback) until commit is called.
2715/// CGP does not check if instructions could be speculatively executed when
2716/// moved. Preserving the original location would pessimize the debugging
2717/// experience, as well as negatively impact the quality of sample PGO.
2718class TypePromotionTransaction {
/// This represents the common interface of the individual transaction.
/// Each class implements the logic for doing one specific modification on
/// the IR via the TypePromotionTransaction.
class TypePromotionAction {
protected:
  /// The Instruction modified.
  Instruction *Inst;

public:
  /// Constructor of the action.
  /// The constructor performs the related action on the IR.
  TypePromotionAction(Instruction *Inst) : Inst(Inst) {}

  virtual ~TypePromotionAction() = default;

  /// Undo the modification done by this action.
  /// When this method is called, the IR must be in the same state as it was
  /// before this action was applied.
  /// \pre Undoing the action works if and only if the IR is in the exact same
  /// state as it was directly after this action was applied.
  virtual void undo() = 0;

  /// Advocate every change made by this action.
  /// When the results on the IR of the action are to be kept, it is important
  /// to call this function, otherwise hidden information may be kept forever.
  virtual void commit() {
    // Nothing to be done, this action is not doing anything.
  }
};

/// Utility to remember the position of an instruction.
class InsertionHandler {
  /// Position of an instruction.
  /// Either an instruction:
  /// - Is the first in a basic block: BB is used.
  /// - Has a previous instruction: PrevInst is used.
  union {
    Instruction *PrevInst;
    BasicBlock *BB;
  } Point;

  /// Remember whether or not the instruction had a previous instruction.
  bool HasPrevInstruction;

public:
  /// Record the position of \p Inst.
  InsertionHandler(Instruction *Inst) {
    BasicBlock::iterator It = Inst->getIterator();
    HasPrevInstruction = (It != (Inst->getParent()->begin()));
    if (HasPrevInstruction)
      Point.PrevInst = &*--It;
    else
      Point.BB = Inst->getParent();
  }

  /// Insert \p Inst at the recorded position.
  void insert(Instruction *Inst) {
    if (HasPrevInstruction) {
      if (Inst->getParent())
        Inst->removeFromParent();
      Inst->insertAfter(Point.PrevInst);
    } else {
      Instruction *Position = &*Point.BB->getFirstInsertionPt();
      if (Inst->getParent())
        Inst->moveBefore(Position);
      else
        Inst->insertBefore(Position);
    }
  }
};

/// Move an instruction before another.
class InstructionMoveBefore : public TypePromotionAction {
  /// Original position of the instruction.
  InsertionHandler Position;

public:
  /// Move \p Inst before \p Before.
  InstructionMoveBefore(Instruction *Inst, Instruction *Before)
      : TypePromotionAction(Inst), Position(Inst) {
    LLVM_DEBUG(dbgs() << "Do: move: " << *Inst << "\nbefore: " << *Beforedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: move: " << *
Inst << "\nbefore: " << *Before << "\n"; } }
 while (false)
                      << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: move: " << *
Inst << "\nbefore: " << *Before << "\n"; } }
 while (false);
    Inst->moveBefore(Before);
  }

  /// Move the instruction back to its original position.
  void undo() override {
    LLVM_DEBUG(dbgs() << "Undo: moveBefore: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: moveBefore: " <<
 *Inst << "\n"; } } while (false);
    Position.insert(Inst);
  }
};

/// Set the operand of an instruction with a new value.
class OperandSetter : public TypePromotionAction {
  /// Original operand of the instruction.
  Value *Origin;

  /// Index of the modified instruction.
  unsigned Idx;

public:
  /// Set \p Idx operand of \p Inst with \p NewVal.
  OperandSetter(Instruction *Inst, unsigned Idx, Value *NewVal)
      : TypePromotionAction(Inst), Idx(Idx) {
    LLVM_DEBUG(dbgs() << "Do: setOperand: " << Idx << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
 Idx << "\n" << "for:" << *Inst << "\n"
 << "with:" << *NewVal << "\n"; } } while (
false)
                      << "for:" << *Inst << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
 Idx << "\n" << "for:" << *Inst << "\n"
 << "with:" << *NewVal << "\n"; } } while (
false)
                      << "with:" << *NewVal << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: setOperand: " <<
 Idx << "\n" << "for:" << *Inst << "\n"
 << "with:" << *NewVal << "\n"; } } while (
false);
    Origin = Inst->getOperand(Idx);
    Inst->setOperand(Idx, NewVal);
  }

  /// Restore the original value of the instruction.
  void undo() override {
    LLVM_DEBUG(dbgs() << "Undo: setOperand:" << Idx << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
 Idx << "\n" << "for: " << *Inst << "\n"
 << "with: " << *Origin << "\n"; } } while (
false)
                      << "for: " << *Inst << "\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
 Idx << "\n" << "for: " << *Inst << "\n"
 << "with: " << *Origin << "\n"; } } while (
false)
                      << "with: " << *Origin << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: setOperand:" <<
 Idx << "\n" << "for: " << *Inst << "\n"
 << "with: " << *Origin << "\n"; } } while (
false);
    Inst->setOperand(Idx, Origin);
  }
};

/// Hide the operands of an instruction.
/// Do as if this instruction was not using any of its operands.
class OperandsHider : public TypePromotionAction {
  /// The list of original operands.
  SmallVector<Value *, 4> OriginalValues;

public:
  /// Remove \p Inst from the uses of the operands of \p Inst.
  OperandsHider(Instruction *Inst) : TypePromotionAction(Inst) {
    LLVM_DEBUG(dbgs() << "Do: OperandsHider: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: OperandsHider: " <<
 *Inst << "\n"; } } while (false);
    unsigned NumOpnds = Inst->getNumOperands();
    OriginalValues.reserve(NumOpnds);
    for (unsigned It = 0; It < NumOpnds; ++It) {
      // Save the current operand.
      Value *Val = Inst->getOperand(It);
      OriginalValues.push_back(Val);
      // Set a dummy one.
      // We could use OperandSetter here, but that would imply an overhead
      // that we are not willing to pay.
      Inst->setOperand(It, UndefValue::get(Val->getType()));
    }
  }

  /// Restore the original list of uses.
  void undo() override {
    LLVM_DEBUG(dbgs() << "Undo: OperandsHider: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: OperandsHider: "
 << *Inst << "\n"; } } while (false);
    for (unsigned It = 0, EndIt = OriginalValues.size(); It != EndIt; ++It)
      Inst->setOperand(It, OriginalValues[It]);
  }
};

/// Build a truncate instruction.
class TruncBuilder : public TypePromotionAction {
  Value *Val;

public:
  /// Build a truncate instruction of \p Opnd producing a \p Ty
  /// result.
  /// trunc Opnd to Ty.
  TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) {
    IRBuilder<> Builder(Opnd);
    Builder.SetCurrentDebugLocation(DebugLoc());
    Val = Builder.CreateTrunc(Opnd, Ty, "promoted");
    LLVM_DEBUG(dbgs() << "Do: TruncBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: TruncBuilder: " <<
 *Val << "\n"; } } while (false);
  }

  /// Get the built value.
  Value *getBuiltValue() { return Val; }

  /// Remove the built instruction.
  void undo() override {
    LLVM_DEBUG(dbgs() << "Undo: TruncBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: TruncBuilder: " <<
 *Val << "\n"; } } while (false);
    if (Instruction *IVal = dyn_cast<Instruction>(Val))
      IVal->eraseFromParent();
  }
};

/// Build a sign extension instruction.
class SExtBuilder : public TypePromotionAction {
  Value *Val;

public:
  /// Build a sign extension instruction of \p Opnd producing a \p Ty
  /// result.
  /// sext Opnd to Ty.
  SExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
      : TypePromotionAction(InsertPt) {
    IRBuilder<> Builder(InsertPt);
    Val = Builder.CreateSExt(Opnd, Ty, "promoted");
    LLVM_DEBUG(dbgs() << "Do: SExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: SExtBuilder: " <<
 *Val << "\n"; } } while (false);
  }

  /// Get the built value.
  Value *getBuiltValue() { return Val; }

  /// Remove the built instruction.
  void undo() override {
    LLVM_DEBUG(dbgs() << "Undo: SExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: SExtBuilder: " <<
 *Val << "\n"; } } while (false);
    if (Instruction *IVal = dyn_cast<Instruction>(Val))
      IVal->eraseFromParent();
  }
};

/// Build a zero extension instruction.
class ZExtBuilder : public TypePromotionAction {
  Value *Val;

public:
  /// Build a zero extension instruction of \p Opnd producing a \p Ty
  /// result.
  /// zext Opnd to Ty.
  ZExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
      : TypePromotionAction(InsertPt) {
    IRBuilder<> Builder(InsertPt);
    Builder.SetCurrentDebugLocation(DebugLoc());
    Val = Builder.CreateZExt(Opnd, Ty, "promoted");
    LLVM_DEBUG(dbgs() << "Do: ZExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: ZExtBuilder: " <<
 *Val << "\n"; } } while (false);
  }

  /// Get the built value.
  Value *getBuiltValue() { return Val; }

  /// Remove the built instruction.
  void undo() override {
    LLVM_DEBUG(dbgs() << "Undo: ZExtBuilder: " << *Val << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: ZExtBuilder: " <<
 *Val << "\n"; } } while (false);
    if (Instruction *IVal = dyn_cast<Instruction>(Val))
      IVal->eraseFromParent();
  }
};

/// Mutate an instruction to another type.
class TypeMutator : public TypePromotionAction {
  /// Record the original type.
  Type *OrigTy;

public:
  /// Mutate the type of \p Inst into \p NewTy.
  TypeMutator(Instruction *Inst, Type *NewTy)
      : TypePromotionAction(Inst), OrigTy(Inst->getType()) {
    LLVM_DEBUG(dbgs() << "Do: MutateType: " << *Inst << " with " << *NewTydo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: MutateType: " <<
 *Inst << " with " << *NewTy << "\n"; } } while
 (false)
                      << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: MutateType: " <<
 *Inst << " with " << *NewTy << "\n"; } } while
 (false);
    Inst->mutateType(NewTy);
  }

  /// Mutate the instruction back to its original type.
  void undo() override {
    LLVM_DEBUG(dbgs() << "Undo: MutateType: " << *Inst << " with " << *OrigTydo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: MutateType: " <<
 *Inst << " with " << *OrigTy << "\n"; } } while
 (false)
                      << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: MutateType: " <<
 *Inst << " with " << *OrigTy << "\n"; } } while
 (false);
    Inst->mutateType(OrigTy);
  }
};

/// Replace the uses of an instruction by another instruction.
class UsesReplacer : public TypePromotionAction {
  /// Helper structure to keep track of the replaced uses.
  struct InstructionAndIdx {
    /// The instruction using the instruction.
    Instruction *Inst;

    /// The index where this instruction is used for Inst.
    unsigned Idx;

    InstructionAndIdx(Instruction *Inst, unsigned Idx)
        : Inst(Inst), Idx(Idx) {}
  };

  /// Keep track of the original uses (pair Instruction, Index).
  SmallVector<InstructionAndIdx, 4> OriginalUses;
  /// Keep track of the debug users.
  SmallVector<DbgValueInst *, 1> DbgValues;

  /// Keep track of the new value so that we can undo it by replacing
  /// instances of the new value with the original value.
  Value *New;

  using use_iterator = SmallVectorImpl<InstructionAndIdx>::iterator;

public:
  /// Replace all the use of \p Inst by \p New.
  UsesReplacer(Instruction *Inst, Value *New)
      : TypePromotionAction(Inst), New(New) {
    LLVM_DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *Newdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: UsersReplacer: " <<
 *Inst << " with " << *New << "\n"; } } while
 (false)
                      << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: UsersReplacer: " <<
 *Inst << " with " << *New << "\n"; } } while
 (false);
    // Record the original uses.
    for (Use &U : Inst->uses()) {
      Instruction *UserI = cast<Instruction>(U.getUser());
      OriginalUses.push_back(InstructionAndIdx(UserI, U.getOperandNo()));
    }
    // Record the debug uses separately. They are not in the instruction's
    // use list, but they are replaced by RAUW.
    findDbgValues(DbgValues, Inst);

    // Now, we can replace the uses.
    Inst->replaceAllUsesWith(New);
  }

  /// Reassign the original uses of Inst to Inst.
  void undo() override {
    LLVM_DEBUG(dbgs() << "Undo: UsersReplacer: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: UsersReplacer: "
 << *Inst << "\n"; } } while (false);
    for (InstructionAndIdx &Use : OriginalUses)
      Use.Inst->setOperand(Use.Idx, Inst);
    // RAUW has replaced all original uses with references to the new value,
    // including the debug uses. Since we are undoing the replacements,
    // the original debug uses must also be reinstated to maintain the
    // correctness and utility of debug value instructions.
    for (auto *DVI : DbgValues)
      DVI->replaceVariableLocationOp(New, Inst);
  }
};

/// Remove an instruction from the IR.
class InstructionRemover : public TypePromotionAction {
  /// Original position of the instruction.
  InsertionHandler Inserter;

  /// Helper structure to hide all the link to the instruction. In other
  /// words, this helps to do as if the instruction was removed.
  OperandsHider Hider;

  /// Keep track of the uses replaced, if any.
  UsesReplacer *Replacer = nullptr;

  /// Keep track of instructions removed.
  SetOfInstrs &RemovedInsts;

public:
  /// Remove all reference of \p Inst and optionally replace all its
  /// uses with New.
  /// \p RemovedInsts Keep track of the instructions removed by this Action.
  /// \pre If !Inst->use_empty(), then New != nullptr
  InstructionRemover(Instruction *Inst, SetOfInstrs &RemovedInsts,
                     Value *New = nullptr)
      : TypePromotionAction(Inst), Inserter(Inst), Hider(Inst),
        RemovedInsts(RemovedInsts) {
    if (New)
      Replacer = new UsesReplacer(Inst, New);
    LLVM_DEBUG(dbgs() << "Do: InstructionRemover: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Do: InstructionRemover: "
 << *Inst << "\n"; } } while (false);
    RemovedInsts.insert(Inst);
    /// The instructions removed here will be freed after completing
    /// optimizeBlock() for all blocks as we need to keep track of the
    /// removed instructions during promotion.
    Inst->removeFromParent();
  }

  ~InstructionRemover() override { delete Replacer; }

  /// Resurrect the instruction and reassign it to the proper uses if
  /// new value was provided when build this action.
  void undo() override {
    LLVM_DEBUG(dbgs() << "Undo: InstructionRemover: " << *Inst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Undo: InstructionRemover: "
 << *Inst << "\n"; } } while (false);
    Inserter.insert(Inst);
    if (Replacer)
      Replacer->undo();
    Hider.undo();
    RemovedInsts.erase(Inst);
  }
};

3077public:
/// Restoration point.
/// The restoration point is a pointer to an action instead of an iterator
/// because the iterator may be invalidated but not the pointer.
using ConstRestorationPt = const TypePromotionAction *;

TypePromotionTransaction(SetOfInstrs &RemovedInsts)
    : RemovedInsts(RemovedInsts) {}

/// Advocate every changes made in that transaction. Return true if any change
/// happen.
bool commit();

/// Undo all the changes made after the given point.
void rollback(ConstRestorationPt Point);

/// Get the current restoration point.
ConstRestorationPt getRestorationPoint() const;

/// \name API for IR modification with state keeping to support rollback.
/// @{
/// Same as Instruction::setOperand.
void setOperand(Instruction *Inst, unsigned Idx, Value *NewVal);

/// Same as Instruction::eraseFromParent.
void eraseInstruction(Instruction *Inst, Value *NewVal = nullptr);

/// Same as Value::replaceAllUsesWith.
void replaceAllUsesWith(Instruction *Inst, Value *New);

/// Same as Value::mutateType.
void mutateType(Instruction *Inst, Type *NewTy);

/// Same as IRBuilder::createTrunc.
Value *createTrunc(Instruction *Opnd, Type *Ty);

/// Same as IRBuilder::createSExt.
Value *createSExt(Instruction *Inst, Value *Opnd, Type *Ty);

/// Same as IRBuilder::createZExt.
Value *createZExt(Instruction *Inst, Value *Opnd, Type *Ty);

/// Same as Instruction::moveBefore.
void moveBefore(Instruction *Inst, Instruction *Before);
/// @}

3123private:
/// The ordered list of actions made so far.
SmallVector<std::unique_ptr<TypePromotionAction>, 16> Actions;

using CommitPt =
    SmallVectorImpl<std::unique_ptr<TypePromotionAction>>::iterator;

SetOfInstrs &RemovedInsts;
3131};

3133} // end anonymous namespace

3135void TypePromotionTransaction::setOperand(Instruction *Inst, unsigned Idx,
                                        Value *NewVal) {
Actions.push_back(std::make_unique<TypePromotionTransaction::OperandSetter>(
    Inst, Idx, NewVal));
3139}

3141void TypePromotionTransaction::eraseInstruction(Instruction *Inst,
                                              Value *NewVal) {
Actions.push_back(
    std::make_unique<TypePromotionTransaction::InstructionRemover>(
        Inst, RemovedInsts, NewVal));
3146}

3148void TypePromotionTransaction::replaceAllUsesWith(Instruction *Inst,
                                                Value *New) {
Actions.push_back(
    std::make_unique<TypePromotionTransaction::UsesReplacer>(Inst, New));
3152}

3154void TypePromotionTransaction::mutateType(Instruction *Inst, Type *NewTy) {
Actions.push_back(
    std::make_unique<TypePromotionTransaction::TypeMutator>(Inst, NewTy));
3157}

3159Value *TypePromotionTransaction::createTrunc(Instruction *Opnd, Type *Ty) {
std::unique_ptr<TruncBuilder> Ptr(new TruncBuilder(Opnd, Ty));
Value *Val = Ptr->getBuiltValue();
Actions.push_back(std::move(Ptr));
return Val;
3164}

3166Value *TypePromotionTransaction::createSExt(Instruction *Inst, Value *Opnd,
                                          Type *Ty) {
std::unique_ptr<SExtBuilder> Ptr(new SExtBuilder(Inst, Opnd, Ty));
Value *Val = Ptr->getBuiltValue();
Actions.push_back(std::move(Ptr));
return Val;
3172}

3174Value *TypePromotionTransaction::createZExt(Instruction *Inst, Value *Opnd,
                                          Type *Ty) {
std::unique_ptr<ZExtBuilder> Ptr(new ZExtBuilder(Inst, Opnd, Ty));
Value *Val = Ptr->getBuiltValue();
Actions.push_back(std::move(Ptr));
return Val;
3180}

3182void TypePromotionTransaction::moveBefore(Instruction *Inst,
                                        Instruction *Before) {
Actions.push_back(
    std::make_unique<TypePromotionTransaction::InstructionMoveBefore>(
        Inst, Before));
3187}

3189TypePromotionTransaction::ConstRestorationPt
3190TypePromotionTransaction::getRestorationPoint() const {
return !Actions.empty() ? Actions.back().get() : nullptr;
3192}

3194bool TypePromotionTransaction::commit() {
for (std::unique_ptr<TypePromotionAction> &Action : Actions)
  Action->commit();
bool Modified = !Actions.empty();
Actions.clear();
return Modified;
3200}

3202void TypePromotionTransaction::rollback(
  TypePromotionTransaction::ConstRestorationPt Point) {
while (!Actions.empty() && Point != Actions.back().get()) {
  std::unique_ptr<TypePromotionAction> Curr = Actions.pop_back_val();
  Curr->undo();
}
3208}

3210namespace {

3212/// A helper class for matching addressing modes.
3213///
3214/// This encapsulates the logic for matching the target-legal addressing modes.
3215class AddressingModeMatcher {
SmallVectorImpl<Instruction *> &AddrModeInsts;
const TargetLowering &TLI;
const TargetRegisterInfo &TRI;
const DataLayout &DL;
const LoopInfo &LI;
const std::function<const DominatorTree &()> getDTFn;

/// AccessTy/MemoryInst - This is the type for the access (e.g. double) and
/// the memory instruction that we're computing this address for.
Type *AccessTy;
unsigned AddrSpace;
Instruction *MemoryInst;

/// This is the addressing mode that we're building up. This is
/// part of the return value of this addressing mode matching stuff.
ExtAddrMode &AddrMode;

/// The instructions inserted by other CodeGenPrepare optimizations.
const SetOfInstrs &InsertedInsts;

/// A map from the instructions to their type before promotion.
InstrToOrigTy &PromotedInsts;

/// The ongoing transaction where every action should be registered.
TypePromotionTransaction &TPT;

// A GEP which has too large offset to be folded into the addressing mode.
std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP;

/// This is set to true when we should not do profitability checks.
/// When true, IsProfitableToFoldIntoAddressingMode always returns true.
bool IgnoreProfitability;

/// True if we are optimizing for size.
bool OptSize = false;

ProfileSummaryInfo *PSI;
BlockFrequencyInfo *BFI;

AddressingModeMatcher(
    SmallVectorImpl<Instruction *> &AMI, const TargetLowering &TLI,
    const TargetRegisterInfo &TRI, const LoopInfo &LI,
    const std::function<const DominatorTree &()> getDTFn, Type *AT,
    unsigned AS, Instruction *MI, ExtAddrMode &AM,
    const SetOfInstrs &InsertedInsts, InstrToOrigTy &PromotedInsts,
    TypePromotionTransaction &TPT,
    std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP,
    bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI)
    : AddrModeInsts(AMI), TLI(TLI), TRI(TRI),
      DL(MI->getModule()->getDataLayout()), LI(LI), getDTFn(getDTFn),
      AccessTy(AT), AddrSpace(AS), MemoryInst(MI), AddrMode(AM),
      InsertedInsts(InsertedInsts), PromotedInsts(PromotedInsts), TPT(TPT),
      LargeOffsetGEP(LargeOffsetGEP), OptSize(OptSize), PSI(PSI), BFI(BFI) {
  IgnoreProfitability = false;
}

3272public:
/// Find the maximal addressing mode that a load/store of V can fold,
/// give an access type of AccessTy.  This returns a list of involved
/// instructions in AddrModeInsts.
/// \p InsertedInsts The instructions inserted by other CodeGenPrepare
/// optimizations.
/// \p PromotedInsts maps the instructions to their type before promotion.
/// \p The ongoing transaction where every action should be registered.
static ExtAddrMode
Match(Value *V, Type *AccessTy, unsigned AS, Instruction *MemoryInst,
      SmallVectorImpl<Instruction *> &AddrModeInsts,
      const TargetLowering &TLI, const LoopInfo &LI,
      const std::function<const DominatorTree &()> getDTFn,
      const TargetRegisterInfo &TRI, const SetOfInstrs &InsertedInsts,
      InstrToOrigTy &PromotedInsts, TypePromotionTransaction &TPT,
      std::pair<AssertingVH<GetElementPtrInst>, int64_t> &LargeOffsetGEP,
      bool OptSize, ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI) {
  ExtAddrMode Result;

  bool Success = AddressingModeMatcher(AddrModeInsts, TLI, TRI, LI, getDTFn,
                                       AccessTy, AS, MemoryInst, Result,
                                       InsertedInsts, PromotedInsts, TPT,
                                       LargeOffsetGEP, OptSize, PSI, BFI)
                     .matchAddr(V, 0);
  (void)Success;
  assert(Success && "Couldn't select *anything*?")(static_cast <bool> (Success && "Couldn't select *anything*?"
) ? void (0) : __assert_fail ("Success && \"Couldn't select *anything*?\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3297, __extension__ __PRETTY_FUNCTION__
));
  return Result;
}

3301private:
bool matchScaledValue(Value *ScaleReg, int64_t Scale, unsigned Depth);
bool matchAddr(Value *Addr, unsigned Depth);
bool matchOperationAddr(User *AddrInst, unsigned Opcode, unsigned Depth,
                        bool *MovedAway = nullptr);
bool isProfitableToFoldIntoAddressingMode(Instruction *I,
                                          ExtAddrMode &AMBefore,
                                          ExtAddrMode &AMAfter);
bool valueAlreadyLiveAtInst(Value *Val, Value *KnownLive1, Value *KnownLive2);
bool isPromotionProfitable(unsigned NewCost, unsigned OldCost,
                           Value *PromotedOperand) const;
3312};

3314class PhiNodeSet;

3316/// An iterator for PhiNodeSet.
3317class PhiNodeSetIterator {
PhiNodeSet *const Set;
size_t CurrentIndex = 0;

3321public:
/// The constructor. Start should point to either a valid element, or be equal
/// to the size of the underlying SmallVector of the PhiNodeSet.
PhiNodeSetIterator(PhiNodeSet *const Set, size_t Start);
PHINode *operator*() const;
PhiNodeSetIterator &operator++();
bool operator==(const PhiNodeSetIterator &RHS) const;
bool operator!=(const PhiNodeSetIterator &RHS) const;
3329};

3331/// Keeps a set of PHINodes.
3332///
3333/// This is a minimal set implementation for a specific use case:
3334/// It is very fast when there are very few elements, but also provides good
3335/// performance when there are many. It is similar to SmallPtrSet, but also
3336/// provides iteration by insertion order, which is deterministic and stable
3337/// across runs. It is also similar to SmallSetVector, but provides removing
3338/// elements in O(1) time. This is achieved by not actually removing the element
3339/// from the underlying vector, so comes at the cost of using more memory, but
3340/// that is fine, since PhiNodeSets are used as short lived objects.
3341class PhiNodeSet {
friend class PhiNodeSetIterator;

using MapType = SmallDenseMap<PHINode *, size_t, 32>;
using iterator = PhiNodeSetIterator;

/// Keeps the elements in the order of their insertion in the underlying
/// vector. To achieve constant time removal, it never deletes any element.
SmallVector<PHINode *, 32> NodeList;

/// Keeps the elements in the underlying set implementation. This (and not the
/// NodeList defined above) is the source of truth on whether an element
/// is actually in the collection.
MapType NodeMap;

/// Points to the first valid (not deleted) element when the set is not empty
/// and the value is not zero. Equals to the size of the underlying vector
/// when the set is empty. When the value is 0, as in the beginning, the
/// first element may or may not be valid.
size_t FirstValidElement = 0;

3362public:
/// Inserts a new element to the collection.
/// \returns true if the element is actually added, i.e. was not in the
/// collection before the operation.
bool insert(PHINode *Ptr) {
  if (NodeMap.insert(std::make_pair(Ptr, NodeList.size())).second) {
    NodeList.push_back(Ptr);
    return true;
  }
  return false;
}

/// Removes the element from the collection.
/// \returns whether the element is actually removed, i.e. was in the
/// collection before the operation.
bool erase(PHINode *Ptr) {
  if (NodeMap.erase(Ptr)) {
    SkipRemovedElements(FirstValidElement);
    return true;
  }
  return false;
}

/// Removes all elements and clears the collection.
void clear() {
  NodeMap.clear();
  NodeList.clear();
  FirstValidElement = 0;
}

/// \returns an iterator that will iterate the elements in the order of
/// insertion.
iterator begin() {
  if (FirstValidElement == 0)
    SkipRemovedElements(FirstValidElement);
  return PhiNodeSetIterator(this, FirstValidElement);
}

/// \returns an iterator that points to the end of the collection.
iterator end() { return PhiNodeSetIterator(this, NodeList.size()); }

/// Returns the number of elements in the collection.
size_t size() const { return NodeMap.size(); }

/// \returns 1 if the given element is in the collection, and 0 if otherwise.
size_t count(PHINode *Ptr) const { return NodeMap.count(Ptr); }

3409private:
/// Updates the CurrentIndex so that it will point to a valid element.
///
/// If the element of NodeList at CurrentIndex is valid, it does not
/// change it. If there are no more valid elements, it updates CurrentIndex
/// to point to the end of the NodeList.
void SkipRemovedElements(size_t &CurrentIndex) {
  while (CurrentIndex < NodeList.size()) {
    auto it = NodeMap.find(NodeList[CurrentIndex]);
    // If the element has been deleted and added again later, NodeMap will
    // point to a different index, so CurrentIndex will still be invalid.
    if (it != NodeMap.end() && it->second == CurrentIndex)
      break;
    ++CurrentIndex;
  }
}
3425};

3427PhiNodeSetIterator::PhiNodeSetIterator(PhiNodeSet *const Set, size_t Start)
  : Set(Set), CurrentIndex(Start) {}

3430PHINode *PhiNodeSetIterator::operator*() const {
assert(CurrentIndex < Set->NodeList.size() &&(static_cast <bool> (CurrentIndex < Set->NodeList
.size() && "PhiNodeSet access out of range") ? void (
0) : __assert_fail ("CurrentIndex < Set->NodeList.size() && \"PhiNodeSet access out of range\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3432, __extension__ __PRETTY_FUNCTION__
))
       "PhiNodeSet access out of range")(static_cast <bool> (CurrentIndex < Set->NodeList
.size() && "PhiNodeSet access out of range") ? void (
0) : __assert_fail ("CurrentIndex < Set->NodeList.size() && \"PhiNodeSet access out of range\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3432, __extension__ __PRETTY_FUNCTION__
));
return Set->NodeList[CurrentIndex];
3434}

3436PhiNodeSetIterator &PhiNodeSetIterator::operator++() {
assert(CurrentIndex < Set->NodeList.size() &&(static_cast <bool> (CurrentIndex < Set->NodeList
.size() && "PhiNodeSet access out of range") ? void (
0) : __assert_fail ("CurrentIndex < Set->NodeList.size() && \"PhiNodeSet access out of range\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3438, __extension__ __PRETTY_FUNCTION__
))
       "PhiNodeSet access out of range")(static_cast <bool> (CurrentIndex < Set->NodeList
.size() && "PhiNodeSet access out of range") ? void (
0) : __assert_fail ("CurrentIndex < Set->NodeList.size() && \"PhiNodeSet access out of range\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3438, __extension__ __PRETTY_FUNCTION__
));
++CurrentIndex;
Set->SkipRemovedElements(CurrentIndex);
return *this;
3442}

3444bool PhiNodeSetIterator::operator==(const PhiNodeSetIterator &RHS) const {
return CurrentIndex == RHS.CurrentIndex;
3446}

3448bool PhiNodeSetIterator::operator!=(const PhiNodeSetIterator &RHS) const {
return !((*this) == RHS);
3450}

3452/// Keep track of simplification of Phi nodes.
3453/// Accept the set of all phi nodes and erase phi node from this set
3454/// if it is simplified.
3455class SimplificationTracker {
DenseMap<Value *, Value *> Storage;
const SimplifyQuery &SQ;
// Tracks newly created Phi nodes. The elements are iterated by insertion
// order.
PhiNodeSet AllPhiNodes;
// Tracks newly created Select nodes.
SmallPtrSet<SelectInst *, 32> AllSelectNodes;

3464public:
SimplificationTracker(const SimplifyQuery &sq) : SQ(sq) {}

Value *Get(Value *V) {
  do {
    auto SV = Storage.find(V);
    if (SV == Storage.end())
      return V;
    V = SV->second;
  } while (true);
}

Value *Simplify(Value *Val) {
  SmallVector<Value *, 32> WorkList;
  SmallPtrSet<Value *, 32> Visited;
  WorkList.push_back(Val);
  while (!WorkList.empty()) {
    auto *P = WorkList.pop_back_val();
    if (!Visited.insert(P).second)
      continue;
    if (auto *PI = dyn_cast<Instruction>(P))
      if (Value *V = simplifyInstruction(cast<Instruction>(PI), SQ)) {
        for (auto *U : PI->users())
          WorkList.push_back(cast<Value>(U));
        Put(PI, V);
        PI->replaceAllUsesWith(V);
        if (auto *PHI = dyn_cast<PHINode>(PI))
          AllPhiNodes.erase(PHI);
        if (auto *Select = dyn_cast<SelectInst>(PI))
          AllSelectNodes.erase(Select);
        PI->eraseFromParent();
      }
  }
  return Get(Val);
}

void Put(Value *From, Value *To) { Storage.insert({From, To}); }

void ReplacePhi(PHINode *From, PHINode *To) {
  Value *OldReplacement = Get(From);
  while (OldReplacement != From) {
    From = To;
    To = dyn_cast<PHINode>(OldReplacement);
    OldReplacement = Get(From);
  }
  assert(To && Get(To) == To && "Replacement PHI node is already replaced.")(static_cast <bool> (To && Get(To) == To &&
 "Replacement PHI node is already replaced.") ? void (0) : __assert_fail
 ("To && Get(To) == To && \"Replacement PHI node is already replaced.\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3509, __extension__ __PRETTY_FUNCTION__
));
  Put(From, To);
  From->replaceAllUsesWith(To);
  AllPhiNodes.erase(From);
  From->eraseFromParent();
}

PhiNodeSet &newPhiNodes() { return AllPhiNodes; }

void insertNewPhi(PHINode *PN) { AllPhiNodes.insert(PN); }

void insertNewSelect(SelectInst *SI) { AllSelectNodes.insert(SI); }

unsigned countNewPhiNodes() const { return AllPhiNodes.size(); }

unsigned countNewSelectNodes() const { return AllSelectNodes.size(); }

void destroyNewNodes(Type *CommonType) {
  // For safe erasing, replace the uses with dummy value first.
  auto *Dummy = PoisonValue::get(CommonType);
  for (auto *I : AllPhiNodes) {
    I->replaceAllUsesWith(Dummy);
    I->eraseFromParent();
  }
  AllPhiNodes.clear();
  for (auto *I : AllSelectNodes) {
    I->replaceAllUsesWith(Dummy);
    I->eraseFromParent();
  }
  AllSelectNodes.clear();
}
3540};

3542/// A helper class for combining addressing modes.
3543class AddressingModeCombiner {
typedef DenseMap<Value *, Value *> FoldAddrToValueMapping;
typedef std::pair<PHINode *, PHINode *> PHIPair;

3547private:
/// The addressing modes we've collected.
SmallVector<ExtAddrMode, 16> AddrModes;

/// The field in which the AddrModes differ, when we have more than one.
ExtAddrMode::FieldName DifferentField = ExtAddrMode::NoField;

/// Are the AddrModes that we have all just equal to their original values?
bool AllAddrModesTrivial = true;

/// Common Type for all different fields in addressing modes.
Type *CommonType = nullptr;

/// SimplifyQuery for simplifyInstruction utility.
const SimplifyQuery &SQ;

/// Original Address.
Value *Original;

/// Common value among addresses
Value *CommonValue = nullptr;

3569public:
AddressingModeCombiner(const SimplifyQuery &_SQ, Value *OriginalValue)
    : SQ(_SQ), Original(OriginalValue) {}

~AddressingModeCombiner() { eraseCommonValueIfDead(); }

/// Get the combined AddrMode
const ExtAddrMode &getAddrMode() const { return AddrModes[0]; }

/// Add a new AddrMode if it's compatible with the AddrModes we already
/// have.
/// \return True iff we succeeded in doing so.
bool addNewAddrMode(ExtAddrMode &NewAddrMode) {
  // Take note of if we have any non-trivial AddrModes, as we need to detect
  // when all AddrModes are trivial as then we would introduce a phi or select
  // which just duplicates what's already there.
  AllAddrModesTrivial = AllAddrModesTrivial && NewAddrMode.isTrivial();

  // If this is the first addrmode then everything is fine.
  if (AddrModes.empty()) {
    AddrModes.emplace_back(NewAddrMode);
    return true;
  }

  // Figure out how different this is from the other address modes, which we
  // can do just by comparing against the first one given that we only care
  // about the cumulative difference.
  ExtAddrMode::FieldName ThisDifferentField =
      AddrModes[0].compare(NewAddrMode);
  if (DifferentField == ExtAddrMode::NoField)
    DifferentField = ThisDifferentField;
  else if (DifferentField != ThisDifferentField)
    DifferentField = ExtAddrMode::MultipleFields;

  // If NewAddrMode differs in more than one dimension we cannot handle it.
  bool CanHandle = DifferentField != ExtAddrMode::MultipleFields;

  // If Scale Field is different then we reject.
  CanHandle = CanHandle && DifferentField != ExtAddrMode::ScaleField;

  // We also must reject the case when base offset is different and
  // scale reg is not null, we cannot handle this case due to merge of
  // different offsets will be used as ScaleReg.
  CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseOffsField ||
                            !NewAddrMode.ScaledReg);

  // We also must reject the case when GV is different and BaseReg installed
  // due to we want to use base reg as a merge of GV values.
  CanHandle = CanHandle && (DifferentField != ExtAddrMode::BaseGVField ||
                            !NewAddrMode.HasBaseReg);

  // Even if NewAddMode is the same we still need to collect it due to
  // original value is different. And later we will need all original values
  // as anchors during finding the common Phi node.
  if (CanHandle)
    AddrModes.emplace_back(NewAddrMode);
  else
    AddrModes.clear();

  return CanHandle;
}

/// Combine the addressing modes we've collected into a single
/// addressing mode.
/// \return True iff we successfully combined them or we only had one so
/// didn't need to combine them anyway.
bool combineAddrModes() {
  // If we have no AddrModes then they can't be combined.
  if (AddrModes.size() == 0)
    return false;

  // A single AddrMode can trivially be combined.
  if (AddrModes.size() == 1 || DifferentField == ExtAddrMode::NoField)
    return true;

  // If the AddrModes we collected are all just equal to the value they are
  // derived from then combining them wouldn't do anything useful.
  if (AllAddrModesTrivial)
    return false;

  if (!addrModeCombiningAllowed())
    return false;

  // Build a map between <original value, basic block where we saw it> to
  // value of base register.
  // Bail out if there is no common type.
  FoldAddrToValueMapping Map;
  if (!initializeMap(Map))
    return false;

  CommonValue = findCommon(Map);
  if (CommonValue)
    AddrModes[0].SetCombinedField(DifferentField, CommonValue, AddrModes);
  return CommonValue != nullptr;
}

3665private:
/// `CommonValue` may be a placeholder inserted by us.
/// If the placeholder is not used, we should remove this dead instruction.
void eraseCommonValueIfDead() {
  if (CommonValue && CommonValue->getNumUses() == 0)
    if (Instruction *CommonInst = dyn_cast<Instruction>(CommonValue))
      CommonInst->eraseFromParent();
}

/// Initialize Map with anchor values. For address seen
/// we set the value of different field saw in this address.
/// At the same time we find a common type for different field we will
/// use to create new Phi/Select nodes. Keep it in CommonType field.
/// Return false if there is no common type found.
bool initializeMap(FoldAddrToValueMapping &Map) {
  // Keep track of keys where the value is null. We will need to replace it
  // with constant null when we know the common type.
  SmallVector<Value *, 2> NullValue;
  Type *IntPtrTy = SQ.DL.getIntPtrType(AddrModes[0].OriginalValue->getType());
  for (auto &AM : AddrModes) {
    Value *DV = AM.GetFieldAsValue(DifferentField, IntPtrTy);
    if (DV) {
      auto *Type = DV->getType();
      if (CommonType && CommonType != Type)
        return false;
      CommonType = Type;
      Map[AM.OriginalValue] = DV;
    } else {
      NullValue.push_back(AM.OriginalValue);
    }
  }
  assert(CommonType && "At least one non-null value must be!")(static_cast <bool> (CommonType && "At least one non-null value must be!"
) ? void (0) : __assert_fail ("CommonType && \"At least one non-null value must be!\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3696, __extension__ __PRETTY_FUNCTION__
));
  for (auto *V : NullValue)
    Map[V] = Constant::getNullValue(CommonType);
  return true;
}

/// We have mapping between value A and other value B where B was a field in
/// addressing mode represented by A. Also we have an original value C
/// representing an address we start with. Traversing from C through phi and
/// selects we ended up with A's in a map. This utility function tries to find
/// a value V which is a field in addressing mode C and traversing through phi
/// nodes and selects we will end up in corresponded values B in a map.
/// The utility will create a new Phi/Selects if needed.
// The simple example looks as follows:
// BB1:
//   p1 = b1 + 40
//   br cond BB2, BB3
// BB2:
//   p2 = b2 + 40
//   br BB3
// BB3:
//   p = phi [p1, BB1], [p2, BB2]
//   v = load p
// Map is
//   p1 -> b1
//   p2 -> b2
// Request is
//   p -> ?
// The function tries to find or build phi [b1, BB1], [b2, BB2] in BB3.
Value *findCommon(FoldAddrToValueMapping &Map) {
  // Tracks the simplification of newly created phi nodes. The reason we use
  // this mapping is because we will add new created Phi nodes in AddrToBase.
  // Simplification of Phi nodes is recursive, so some Phi node may
  // be simplified after we added it to AddrToBase. In reality this
  // simplification is possible only if original phi/selects were not
  // simplified yet.
  // Using this mapping we can find the current value in AddrToBase.
  SimplificationTracker ST(SQ);

  // First step, DFS to create PHI nodes for all intermediate blocks.
  // Also fill traverse order for the second step.
  SmallVector<Value *, 32> TraverseOrder;
  InsertPlaceholders(Map, TraverseOrder, ST);

  // Second Step, fill new nodes by merged values and simplify if possible.
  FillPlaceholders(Map, TraverseOrder, ST);

  if (!AddrSinkNewSelects && ST.countNewSelectNodes() > 0) {
    ST.destroyNewNodes(CommonType);
    return nullptr;
  }

  // Now we'd like to match New Phi nodes to existed ones.
  unsigned PhiNotMatchedCount = 0;
  if (!MatchPhiSet(ST, AddrSinkNewPhis, PhiNotMatchedCount)) {
    ST.destroyNewNodes(CommonType);
    return nullptr;
  }

  auto *Result = ST.Get(Map.find(Original)->second);
  if (Result) {
    NumMemoryInstsPhiCreated += ST.countNewPhiNodes() + PhiNotMatchedCount;
    NumMemoryInstsSelectCreated += ST.countNewSelectNodes();
  }
  return Result;
}

/// Try to match PHI node to Candidate.
/// Matcher tracks the matched Phi nodes.
bool MatchPhiNode(PHINode *PHI, PHINode *Candidate,
                  SmallSetVector<PHIPair, 8> &Matcher,
                  PhiNodeSet &PhiNodesToMatch) {
  SmallVector<PHIPair, 8> WorkList;
  Matcher.insert({PHI, Candidate});
  SmallSet<PHINode *, 8> MatchedPHIs;
  MatchedPHIs.insert(PHI);
  WorkList.push_back({PHI, Candidate});
  SmallSet<PHIPair, 8> Visited;
  while (!WorkList.empty()) {
    auto Item = WorkList.pop_back_val();
    if (!Visited.insert(Item).second)
      continue;
    // We iterate over all incoming values to Phi to compare them.
    // If values are different and both of them Phi and the first one is a
    // Phi we added (subject to match) and both of them is in the same basic
    // block then we can match our pair if values match. So we state that
    // these values match and add it to work list to verify that.
    for (auto *B : Item.first->blocks()) {
      Value *FirstValue = Item.first->getIncomingValueForBlock(B);
      Value *SecondValue = Item.second->getIncomingValueForBlock(B);
      if (FirstValue == SecondValue)
        continue;

      PHINode *FirstPhi = dyn_cast<PHINode>(FirstValue);
      PHINode *SecondPhi = dyn_cast<PHINode>(SecondValue);

      // One of them is not Phi or
      // The first one is not Phi node from the set we'd like to match or
      // Phi nodes from different basic blocks then
      // we will not be able to match.
      if (!FirstPhi || !SecondPhi || !PhiNodesToMatch.count(FirstPhi) ||
          FirstPhi->getParent() != SecondPhi->getParent())
        return false;

      // If we already matched them then continue.
      if (Matcher.count({FirstPhi, SecondPhi}))
        continue;
      // So the values are different and does not match. So we need them to
      // match. (But we register no more than one match per PHI node, so that
      // we won't later try to replace them twice.)
      if (MatchedPHIs.insert(FirstPhi).second)
        Matcher.insert({FirstPhi, SecondPhi});
      // But me must check it.
      WorkList.push_back({FirstPhi, SecondPhi});
    }
  }
  return true;
}

/// For the given set of PHI nodes (in the SimplificationTracker) try
/// to find their equivalents.
/// Returns false if this matching fails and creation of new Phi is disabled.
bool MatchPhiSet(SimplificationTracker &ST, bool AllowNewPhiNodes,
                 unsigned &PhiNotMatchedCount) {
  // Matched and PhiNodesToMatch iterate their elements in a deterministic
  // order, so the replacements (ReplacePhi) are also done in a deterministic
  // order.
  SmallSetVector<PHIPair, 8> Matched;
  SmallPtrSet<PHINode *, 8> WillNotMatch;
  PhiNodeSet &PhiNodesToMatch = ST.newPhiNodes();
  while (PhiNodesToMatch.size()) {
    PHINode *PHI = *PhiNodesToMatch.begin();

    // Add us, if no Phi nodes in the basic block we do not match.
    WillNotMatch.clear();
    WillNotMatch.insert(PHI);

    // Traverse all Phis until we found equivalent or fail to do that.
    bool IsMatched = false;
    for (auto &P : PHI->getParent()->phis()) {
      // Skip new Phi nodes.
      if (PhiNodesToMatch.count(&P))
        continue;
      if ((IsMatched = MatchPhiNode(PHI, &P, Matched, PhiNodesToMatch)))
        break;
      // If it does not match, collect all Phi nodes from matcher.
      // if we end up with no match, them all these Phi nodes will not match
      // later.
      for (auto M : Matched)
        WillNotMatch.insert(M.first);
      Matched.clear();
    }
    if (IsMatched) {
      // Replace all matched values and erase them.
      for (auto MV : Matched)
        ST.ReplacePhi(MV.first, MV.second);
      Matched.clear();
      continue;
    }
    // If we are not allowed to create new nodes then bail out.
    if (!AllowNewPhiNodes)
      return false;
    // Just remove all seen values in matcher. They will not match anything.
    PhiNotMatchedCount += WillNotMatch.size();
    for (auto *P : WillNotMatch)
      PhiNodesToMatch.erase(P);
  }
  return true;
}
/// Fill the placeholders with values from predecessors and simplify them.
void FillPlaceholders(FoldAddrToValueMapping &Map,
                      SmallVectorImpl<Value *> &TraverseOrder,
                      SimplificationTracker &ST) {
  while (!TraverseOrder.empty()) {
    Value *Current = TraverseOrder.pop_back_val();
    assert(Map.contains(Current) && "No node to fill!!!")(static_cast <bool> (Map.contains(Current) && "No node to fill!!!"
) ? void (0) : __assert_fail ("Map.contains(Current) && \"No node to fill!!!\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3871, __extension__ __PRETTY_FUNCTION__
));
    Value *V = Map[Current];

    if (SelectInst *Select = dyn_cast<SelectInst>(V)) {
      // CurrentValue also must be Select.
      auto *CurrentSelect = cast<SelectInst>(Current);
      auto *TrueValue = CurrentSelect->getTrueValue();
      assert(Map.contains(TrueValue) && "No True Value!")(static_cast <bool> (Map.contains(TrueValue) &&
 "No True Value!") ? void (0) : __assert_fail ("Map.contains(TrueValue) && \"No True Value!\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3878, __extension__ __PRETTY_FUNCTION__
));
      Select->setTrueValue(ST.Get(Map[TrueValue]));
      auto *FalseValue = CurrentSelect->getFalseValue();
      assert(Map.contains(FalseValue) && "No False Value!")(static_cast <bool> (Map.contains(FalseValue) &&
 "No False Value!") ? void (0) : __assert_fail ("Map.contains(FalseValue) && \"No False Value!\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3881, __extension__ __PRETTY_FUNCTION__
));
      Select->setFalseValue(ST.Get(Map[FalseValue]));
    } else {
      // Must be a Phi node then.
      auto *PHI = cast<PHINode>(V);
      // Fill the Phi node with values from predecessors.
      for (auto *B : predecessors(PHI->getParent())) {
        Value *PV = cast<PHINode>(Current)->getIncomingValueForBlock(B);
        assert(Map.contains(PV) && "No predecessor Value!")(static_cast <bool> (Map.contains(PV) && "No predecessor Value!"
) ? void (0) : __assert_fail ("Map.contains(PV) && \"No predecessor Value!\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3889, __extension__ __PRETTY_FUNCTION__
));
        PHI->addIncoming(ST.Get(Map[PV]), B);
      }
    }
    Map[Current] = ST.Simplify(V);
  }
}

/// Starting from original value recursively iterates over def-use chain up to
/// known ending values represented in a map. For each traversed phi/select
/// inserts a placeholder Phi or Select.
/// Reports all new created Phi/Select nodes by adding them to set.
/// Also reports and order in what values have been traversed.
void InsertPlaceholders(FoldAddrToValueMapping &Map,
                        SmallVectorImpl<Value *> &TraverseOrder,
                        SimplificationTracker &ST) {
  SmallVector<Value *, 32> Worklist;
  assert((isa<PHINode>(Original) || isa<SelectInst>(Original)) &&(static_cast <bool> ((isa<PHINode>(Original) || isa
<SelectInst>(Original)) && "Address must be a Phi or Select node"
) ? void (0) : __assert_fail ("(isa<PHINode>(Original) || isa<SelectInst>(Original)) && \"Address must be a Phi or Select node\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3907, __extension__ __PRETTY_FUNCTION__
))
         "Address must be a Phi or Select node")(static_cast <bool> ((isa<PHINode>(Original) || isa
<SelectInst>(Original)) && "Address must be a Phi or Select node"
) ? void (0) : __assert_fail ("(isa<PHINode>(Original) || isa<SelectInst>(Original)) && \"Address must be a Phi or Select node\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 3907, __extension__ __PRETTY_FUNCTION__
));
  auto *Dummy = PoisonValue::get(CommonType);
  Worklist.push_back(Original);
  while (!Worklist.empty()) {
    Value *Current = Worklist.pop_back_val();
    // if it is already visited or it is an ending value then skip it.
    if (Map.contains(Current))
      continue;
    TraverseOrder.push_back(Current);

    // CurrentValue must be a Phi node or select. All others must be covered
    // by anchors.
    if (SelectInst *CurrentSelect = dyn_cast<SelectInst>(Current)) {
      // Is it OK to get metadata from OrigSelect?!
      // Create a Select placeholder with dummy value.
      SelectInst *Select = SelectInst::Create(
          CurrentSelect->getCondition(), Dummy, Dummy,
          CurrentSelect->getName(), CurrentSelect, CurrentSelect);
      Map[Current] = Select;
      ST.insertNewSelect(Select);
      // We are interested in True and False values.
      Worklist.push_back(CurrentSelect->getTrueValue());
      Worklist.push_back(CurrentSelect->getFalseValue());
    } else {
      // It must be a Phi node then.
      PHINode *CurrentPhi = cast<PHINode>(Current);
      unsigned PredCount = CurrentPhi->getNumIncomingValues();
      PHINode *PHI =
          PHINode::Create(CommonType, PredCount, "sunk_phi", CurrentPhi);
      Map[Current] = PHI;
      ST.insertNewPhi(PHI);
      append_range(Worklist, CurrentPhi->incoming_values());
    }
  }
}

bool addrModeCombiningAllowed() {
  if (DisableComplexAddrModes)
    return false;
  switch (DifferentField) {
  default:
    return false;
  case ExtAddrMode::BaseRegField:
    return AddrSinkCombineBaseReg;
  case ExtAddrMode::BaseGVField:
    return AddrSinkCombineBaseGV;
  case ExtAddrMode::BaseOffsField:
    return AddrSinkCombineBaseOffs;
  case ExtAddrMode::ScaledRegField:
    return AddrSinkCombineScaledReg;
  }
}
3959};
3960} // end anonymous namespace

3962/// Try adding ScaleReg*Scale to the current addressing mode.
3963/// Return true and update AddrMode if this addr mode is legal for the target,
3964/// false if not.
3965bool AddressingModeMatcher::matchScaledValue(Value *ScaleReg, int64_t Scale,
                                           unsigned Depth) {
// If Scale is 1, then this is the same as adding ScaleReg to the addressing
// mode.  Just process that directly.
if (Scale == 1)
  return matchAddr(ScaleReg, Depth);

// If the scale is 0, it takes nothing to add this.
if (Scale == 0)
  return true;

// If we already have a scale of this value, we can add to it, otherwise, we
// need an available scale field.
if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg)
  return false;

ExtAddrMode TestAddrMode = AddrMode;

// Add scale to turn X*4+X*3 -> X*7.  This could also do things like
// [A+B + A*7] -> [B+A*8].
TestAddrMode.Scale += Scale;
TestAddrMode.ScaledReg = ScaleReg;

// If the new address isn't legal, bail out.
if (!TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace))
  return false;

// It was legal, so commit it.
AddrMode = TestAddrMode;

// Okay, we decided that we can add ScaleReg+Scale to AddrMode.  Check now
// to see if ScaleReg is actually X+C.  If so, we can turn this into adding
// X*Scale + C*Scale to addr mode. If we found available IV increment, do not
// go any further: we can reuse it and cannot eliminate it.
ConstantInt *CI = nullptr;
Value *AddLHS = nullptr;
if (isa<Instruction>(ScaleReg) && // not a constant expr.
    match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI))) &&
    !isIVIncrement(ScaleReg, &LI) && CI->getValue().isSignedIntN(64)) {
  TestAddrMode.InBounds = false;
  TestAddrMode.ScaledReg = AddLHS;
  TestAddrMode.BaseOffs += CI->getSExtValue() * TestAddrMode.Scale;

  // If this addressing mode is legal, commit it and remember that we folded
  // this instruction.
  if (TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace)) {
    AddrModeInsts.push_back(cast<Instruction>(ScaleReg));
    AddrMode = TestAddrMode;
    return true;
  }
  // Restore status quo.
  TestAddrMode = AddrMode;
}

// If this is an add recurrence with a constant step, return the increment
// instruction and the canonicalized step.
auto GetConstantStep =
    [this](const Value *V) -> std::optional<std::pair<Instruction *, APInt>> {
  auto *PN = dyn_cast<PHINode>(V);
  if (!PN)
    return std::nullopt;
  auto IVInc = getIVIncrement(PN, &LI);
  if (!IVInc)
    return std::nullopt;
  // TODO: The result of the intrinsics above is two-complement. However when
  // IV inc is expressed as add or sub, iv.next is potentially a poison value.
  // If it has nuw or nsw flags, we need to make sure that these flags are
  // inferrable at the point of memory instruction. Otherwise we are replacing
  // well-defined two-complement computation with poison. Currently, to avoid
  // potentially complex analysis needed to prove this, we reject such cases.
  if (auto *OIVInc = dyn_cast<OverflowingBinaryOperator>(IVInc->first))
    if (OIVInc->hasNoSignedWrap() || OIVInc->hasNoUnsignedWrap())
      return std::nullopt;
  if (auto *ConstantStep = dyn_cast<ConstantInt>(IVInc->second))
    return std::make_pair(IVInc->first, ConstantStep->getValue());
  return std::nullopt;
};

// Try to account for the following special case:
// 1. ScaleReg is an inductive variable;
// 2. We use it with non-zero offset;
// 3. IV's increment is available at the point of memory instruction.
//
// In this case, we may reuse the IV increment instead of the IV Phi to
// achieve the following advantages:
// 1. If IV step matches the offset, we will have no need in the offset;
// 2. Even if they don't match, we will reduce the overlap of living IV
//    and IV increment, that will potentially lead to better register
//    assignment.
if (AddrMode.BaseOffs) {
  if (auto IVStep = GetConstantStep(ScaleReg)) {
    Instruction *IVInc = IVStep->first;
    // The following assert is important to ensure a lack of infinite loops.
    // This transforms is (intentionally) the inverse of the one just above.
    // If they don't agree on the definition of an increment, we'd alternate
    // back and forth indefinitely.
    assert(isIVIncrement(IVInc, &LI) && "implied by GetConstantStep")(static_cast <bool> (isIVIncrement(IVInc, &LI) &&
 "implied by GetConstantStep") ? void (0) : __assert_fail ("isIVIncrement(IVInc, &LI) && \"implied by GetConstantStep\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 4061, __extension__ __PRETTY_FUNCTION__
));
    APInt Step = IVStep->second;
    APInt Offset = Step * AddrMode.Scale;
    if (Offset.isSignedIntN(64)) {
      TestAddrMode.InBounds = false;
      TestAddrMode.ScaledReg = IVInc;
      TestAddrMode.BaseOffs -= Offset.getLimitedValue();
      // If this addressing mode is legal, commit it..
      // (Note that we defer the (expensive) domtree base legality check
      // to the very last possible point.)
      if (TLI.isLegalAddressingMode(DL, TestAddrMode, AccessTy, AddrSpace) &&
          getDTFn().dominates(IVInc, MemoryInst)) {
        AddrModeInsts.push_back(cast<Instruction>(IVInc));
        AddrMode = TestAddrMode;
        return true;
      }
      // Restore status quo.
      TestAddrMode = AddrMode;
    }
  }
}

// Otherwise, just return what we have.
return true;
4085}

4087/// This is a little filter, which returns true if an addressing computation
4088/// involving I might be folded into a load/store accessing it.
4089/// This doesn't need to be perfect, but needs to accept at least
4090/// the set of instructions that MatchOperationAddr can.
4091static bool MightBeFoldableInst(Instruction *I) {
switch (I->getOpcode()) {
case Instruction::BitCast:
case Instruction::AddrSpaceCast:
  // Don't touch identity bitcasts.
  if (I->getType() == I->getOperand(0)->getType())
    return false;
  return I->getType()->isIntOrPtrTy();
case Instruction::PtrToInt:
  // PtrToInt is always a noop, as we know that the int type is pointer sized.
  return true;
case Instruction::IntToPtr:
  // We know the input is intptr_t, so this is foldable.
  return true;
case Instruction::Add:
  return true;
case Instruction::Mul:
case Instruction::Shl:
  // Can only handle X*C and X << C.
  return isa<ConstantInt>(I->getOperand(1));
case Instruction::GetElementPtr:
  return true;
default:
  return false;
}
4116}

4118/// Check whether or not \p Val is a legal instruction for \p TLI.
4119/// \note \p Val is assumed to be the product of some type promotion.
4120/// Therefore if \p Val has an undefined state in \p TLI, this is assumed
4121/// to be legal, as the non-promoted value would have had the same state.
4122static bool isPromotedInstructionLegal(const TargetLowering &TLI,
                                     const DataLayout &DL, Value *Val) {
Instruction *PromotedInst = dyn_cast<Instruction>(Val);
if (!PromotedInst)
  return false;
int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode());
// If the ISDOpcode is undefined, it was undefined before the promotion.
if (!ISDOpcode)
  return true;
// Otherwise, check if the promoted instruction is legal or not.
return TLI.isOperationLegalOrCustom(
    ISDOpcode, TLI.getValueType(DL, PromotedInst->getType()));
4134}

4136namespace {

4138/// Hepler class to perform type promotion.
4139class TypePromotionHelper {
/// Utility function to add a promoted instruction \p ExtOpnd to
/// \p PromotedInsts and record the type of extension we have seen.
static void addPromotedInst(InstrToOrigTy &PromotedInsts,
                            Instruction *ExtOpnd, bool IsSExt) {
  ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension;
  InstrToOrigTy::iterator It = PromotedInsts.find(ExtOpnd);
  if (It != PromotedInsts.end()) {
    // If the new extension is same as original, the information in
    // PromotedInsts[ExtOpnd] is still correct.
    if (It->second.getInt() == ExtTy)
      return;

    // Now the new extension is different from old extension, we make
    // the type information invalid by setting extension type to
    // BothExtension.
    ExtTy = BothExtension;
  }
  PromotedInsts[ExtOpnd] = TypeIsSExt(ExtOpnd->getType(), ExtTy);
}

/// Utility function to query the original type of instruction \p Opnd
/// with a matched extension type. If the extension doesn't match, we
/// cannot use the information we had on the original type.
/// BothExtension doesn't match any extension type.
static const Type *getOrigType(const InstrToOrigTy &PromotedInsts,
                               Instruction *Opnd, bool IsSExt) {
  ExtType ExtTy = IsSExt ? SignExtension : ZeroExtension;
  InstrToOrigTy::const_iterator It = PromotedInsts.find(Opnd);
  if (It != PromotedInsts.end() && It->second.getInt() == ExtTy)
    return It->second.getPointer();
  return nullptr;
}

/// Utility function to check whether or not a sign or zero extension
/// of \p Inst with \p ConsideredExtType can be moved through \p Inst by
/// either using the operands of \p Inst or promoting \p Inst.
/// The type of the extension is defined by \p IsSExt.
/// In other words, check if:
/// ext (Ty Inst opnd1 opnd2 ... opndN) to ConsideredExtType.
/// #1 Promotion applies:
/// ConsideredExtType Inst (ext opnd1 to ConsideredExtType, ...).
/// #2 Operand reuses:
/// ext opnd1 to ConsideredExtType.
/// \p PromotedInsts maps the instructions to their type before promotion.
static bool canGetThrough(const Instruction *Inst, Type *ConsideredExtType,
                          const InstrToOrigTy &PromotedInsts, bool IsSExt);

/// Utility function to determine if \p OpIdx should be promoted when
/// promoting \p Inst.
static bool shouldExtOperand(const Instruction *Inst, int OpIdx) {
  return !(isa<SelectInst>(Inst) && OpIdx == 0);
}

/// Utility function to promote the operand of \p Ext when this
/// operand is a promotable trunc or sext or zext.
/// \p PromotedInsts maps the instructions to their type before promotion.
/// \p CreatedInstsCost[out] contains the cost of all instructions
/// created to promote the operand of Ext.
/// Newly added extensions are inserted in \p Exts.
/// Newly added truncates are inserted in \p Truncs.
/// Should never be called directly.
/// \return The promoted value which is used instead of Ext.
static Value *promoteOperandForTruncAndAnyExt(
    Instruction *Ext, TypePromotionTransaction &TPT,
    InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
    SmallVectorImpl<Instruction *> *Exts,
    SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI);

/// Utility function to promote the operand of \p Ext when this
/// operand is promotable and is not a supported trunc or sext.
/// \p PromotedInsts maps the instructions to their type before promotion.
/// \p CreatedInstsCost[out] contains the cost of all the instructions
/// created to promote the operand of Ext.
/// Newly added extensions are inserted in \p Exts.
/// Newly added truncates are inserted in \p Truncs.
/// Should never be called directly.
/// \return The promoted value which is used instead of Ext.
static Value *promoteOperandForOther(Instruction *Ext,
                                     TypePromotionTransaction &TPT,
                                     InstrToOrigTy &PromotedInsts,
                                     unsigned &CreatedInstsCost,
                                     SmallVectorImpl<Instruction *> *Exts,
                                     SmallVectorImpl<Instruction *> *Truncs,
                                     const TargetLowering &TLI, bool IsSExt);

/// \see promoteOperandForOther.
static Value *signExtendOperandForOther(
    Instruction *Ext, TypePromotionTransaction &TPT,
    InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
    SmallVectorImpl<Instruction *> *Exts,
    SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
  return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
                                Exts, Truncs, TLI, true);
}

/// \see promoteOperandForOther.
static Value *zeroExtendOperandForOther(
    Instruction *Ext, TypePromotionTransaction &TPT,
    InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
    SmallVectorImpl<Instruction *> *Exts,
    SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
  return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInstsCost,
                                Exts, Truncs, TLI, false);
}

4245public:
/// Type for the utility function that promotes the operand of Ext.
using Action = Value *(*)(Instruction *Ext, TypePromotionTransaction &TPT,
                          InstrToOrigTy &PromotedInsts,
                          unsigned &CreatedInstsCost,
                          SmallVectorImpl<Instruction *> *Exts,
                          SmallVectorImpl<Instruction *> *Truncs,
                          const TargetLowering &TLI);

/// Given a sign/zero extend instruction \p Ext, return the appropriate
/// action to promote the operand of \p Ext instead of using Ext.
/// \return NULL if no promotable action is possible with the current
/// sign extension.
/// \p InsertedInsts keeps track of all the instructions inserted by the
/// other CodeGenPrepare optimizations. This information is important
/// because we do not want to promote these instructions as CodeGenPrepare
/// will reinsert them later. Thus creating an infinite loop: create/remove.
/// \p PromotedInsts maps the instructions to their type before promotion.
static Action getAction(Instruction *Ext, const SetOfInstrs &InsertedInsts,
                        const TargetLowering &TLI,
                        const InstrToOrigTy &PromotedInsts);
4266};

4268} // end anonymous namespace

4270bool TypePromotionHelper::canGetThrough(const Instruction *Inst,
                                      Type *ConsideredExtType,
                                      const InstrToOrigTy &PromotedInsts,
                                      bool IsSExt) {
// The promotion helper does not know how to deal with vector types yet.
// To be able to fix that, we would need to fix the places where we
// statically extend, e.g., constants and such.
if (Inst->getType()->isVectorTy())
  return false;

// We can always get through zext.
if (isa<ZExtInst>(Inst))
  return true;

// sext(sext) is ok too.
if (IsSExt && isa<SExtInst>(Inst))
  return true;

// We can get through binary operator, if it is legal. In other words, the
// binary operator must have a nuw or nsw flag.
if (const auto *BinOp = dyn_cast<BinaryOperator>(Inst))
  if (isa<OverflowingBinaryOperator>(BinOp) &&
      ((!IsSExt && BinOp->hasNoUnsignedWrap()) ||
       (IsSExt && BinOp->hasNoSignedWrap())))
    return true;

// ext(and(opnd, cst)) --> and(ext(opnd), ext(cst))
if ((Inst->getOpcode() == Instruction::And ||
     Inst->getOpcode() == Instruction::Or))
  return true;

// ext(xor(opnd, cst)) --> xor(ext(opnd), ext(cst))
if (Inst->getOpcode() == Instruction::Xor) {
  // Make sure it is not a NOT.
  if (const auto *Cst = dyn_cast<ConstantInt>(Inst->getOperand(1)))
    if (!Cst->getValue().isAllOnes())
      return true;
}

// zext(shrl(opnd, cst)) --> shrl(zext(opnd), zext(cst))
// It may change a poisoned value into a regular value, like
//     zext i32 (shrl i8 %val, 12)  -->  shrl i32 (zext i8 %val), 12
//          poisoned value                    regular value
// It should be OK since undef covers valid value.
if (Inst->getOpcode() == Instruction::LShr && !IsSExt)
  return true;

// and(ext(shl(opnd, cst)), cst) --> and(shl(ext(opnd), ext(cst)), cst)
// It may change a poisoned value into a regular value, like
//     zext i32 (shl i8 %val, 12)  -->  shl i32 (zext i8 %val), 12
//          poisoned value                    regular value
// It should be OK since undef covers valid value.
if (Inst->getOpcode() == Instruction::Shl && Inst->hasOneUse()) {
  const auto *ExtInst = cast<const Instruction>(*Inst->user_begin());
  if (ExtInst->hasOneUse()) {
    const auto *AndInst = dyn_cast<const Instruction>(*ExtInst->user_begin());
    if (AndInst && AndInst->getOpcode() == Instruction::And) {
      const auto *Cst = dyn_cast<ConstantInt>(AndInst->getOperand(1));
      if (Cst &&
          Cst->getValue().isIntN(Inst->getType()->getIntegerBitWidth()))
        return true;
    }
  }
}

// Check if we can do the following simplification.
// ext(trunc(opnd)) --> ext(opnd)
if (!isa<TruncInst>(Inst))
  return false;

Value *OpndVal = Inst->getOperand(0);
// Check if we can use this operand in the extension.
// If the type is larger than the result type of the extension, we cannot.
if (!OpndVal->getType()->isIntegerTy() ||
    OpndVal->getType()->getIntegerBitWidth() >
        ConsideredExtType->getIntegerBitWidth())
  return false;

// If the operand of the truncate is not an instruction, we will not have
// any information on the dropped bits.
// (Actually we could for constant but it is not worth the extra logic).
Instruction *Opnd = dyn_cast<Instruction>(OpndVal);
if (!Opnd)
  return false;

// Check if the source of the type is narrow enough.
// I.e., check that trunc just drops extended bits of the same kind of
// the extension.
// #1 get the type of the operand and check the kind of the extended bits.
const Type *OpndType = getOrigType(PromotedInsts, Opnd, IsSExt);
if (OpndType)
  ;
else if ((IsSExt && isa<SExtInst>(Opnd)) || (!IsSExt && isa<ZExtInst>(Opnd)))
  OpndType = Opnd->getOperand(0)->getType();
else
  return false;

// #2 check that the truncate just drops extended bits.
return Inst->getType()->getIntegerBitWidth() >=
       OpndType->getIntegerBitWidth();
4370}

4372TypePromotionHelper::Action TypePromotionHelper::getAction(
  Instruction *Ext, const SetOfInstrs &InsertedInsts,
  const TargetLowering &TLI, const InstrToOrigTy &PromotedInsts) {
assert((isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) &&(static_cast <bool> ((isa<SExtInst>(Ext) || isa<
ZExtInst>(Ext)) && "Unexpected instruction type") ?
 void (0) : __assert_fail ("(isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) && \"Unexpected instruction type\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 4376, __extension__ __PRETTY_FUNCTION__
))
       "Unexpected instruction type")(static_cast <bool> ((isa<SExtInst>(Ext) || isa<
ZExtInst>(Ext)) && "Unexpected instruction type") ?
 void (0) : __assert_fail ("(isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) && \"Unexpected instruction type\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 4376, __extension__ __PRETTY_FUNCTION__
));
Instruction *ExtOpnd = dyn_cast<Instruction>(Ext->getOperand(0));
Type *ExtTy = Ext->getType();
bool IsSExt = isa<SExtInst>(Ext);
// If the operand of the extension is not an instruction, we cannot
// get through.
// If it, check we can get through.
if (!ExtOpnd || !canGetThrough(ExtOpnd, ExtTy, PromotedInsts, IsSExt))
  return nullptr;

// Do not promote if the operand has been added by codegenprepare.
// Otherwise, it means we are undoing an optimization that is likely to be
// redone, thus causing potential infinite loop.
if (isa<TruncInst>(ExtOpnd) && InsertedInsts.count(ExtOpnd))
  return nullptr;

// SExt or Trunc instructions.
// Return the related handler.
if (isa<SExtInst>(ExtOpnd) || isa<TruncInst>(ExtOpnd) ||
    isa<ZExtInst>(ExtOpnd))
  return promoteOperandForTruncAndAnyExt;

// Regular instruction.
// Abort early if we will have to insert non-free instructions.
if (!ExtOpnd->hasOneUse() && !TLI.isTruncateFree(ExtTy, ExtOpnd->getType()))
  return nullptr;
return IsSExt ? signExtendOperandForOther : zeroExtendOperandForOther;
4403}

4405Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
  Instruction *SExt, TypePromotionTransaction &TPT,
  InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
  SmallVectorImpl<Instruction *> *Exts,
  SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI) {
// By construction, the operand of SExt is an instruction. Otherwise we cannot
// get through it and this method should not be called.
Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0));
Value *ExtVal = SExt;
bool HasMergedNonFreeExt = false;
if (isa<ZExtInst>(SExtOpnd)) {
  // Replace s|zext(zext(opnd))
  // => zext(opnd).
  HasMergedNonFreeExt = !TLI.isExtFree(SExtOpnd);
  Value *ZExt =
      TPT.createZExt(SExt, SExtOpnd->getOperand(0), SExt->getType());
  TPT.replaceAllUsesWith(SExt, ZExt);
  TPT.eraseInstruction(SExt);
  ExtVal = ZExt;
} else {
  // Replace z|sext(trunc(opnd)) or sext(sext(opnd))
  // => z|sext(opnd).
  TPT.setOperand(SExt, 0, SExtOpnd->getOperand(0));
}
CreatedInstsCost = 0;

// Remove dead code.
if (SExtOpnd->use_empty())
  TPT.eraseInstruction(SExtOpnd);

// Check if the extension is still needed.
Instruction *ExtInst = dyn_cast<Instruction>(ExtVal);
if (!ExtInst || ExtInst->getType() != ExtInst->getOperand(0)->getType()) {
  if (ExtInst) {
    if (Exts)
      Exts->push_back(ExtInst);
    CreatedInstsCost = !TLI.isExtFree(ExtInst) && !HasMergedNonFreeExt;
  }
  return ExtVal;
}

// At this point we have: ext ty opnd to ty.
// Reassign the uses of ExtInst to the opnd and remove ExtInst.
Value *NextVal = ExtInst->getOperand(0);
TPT.eraseInstruction(ExtInst, NextVal);
return NextVal;
4451}

4453Value *TypePromotionHelper::promoteOperandForOther(
  Instruction *Ext, TypePromotionTransaction &TPT,
  InstrToOrigTy &PromotedInsts, unsigned &CreatedInstsCost,
  SmallVectorImpl<Instruction *> *Exts,
  SmallVectorImpl<Instruction *> *Truncs, const TargetLowering &TLI,
  bool IsSExt) {
// By construction, the operand of Ext is an instruction. Otherwise we cannot
// get through it and this method should not be called.
Instruction *ExtOpnd = cast<Instruction>(Ext->getOperand(0));
CreatedInstsCost = 0;
if (!ExtOpnd->hasOneUse()) {
  // ExtOpnd will be promoted.
  // All its uses, but Ext, will need to use a truncated value of the
  // promoted version.
  // Create the truncate now.
  Value *Trunc = TPT.createTrunc(Ext, ExtOpnd->getType());
  if (Instruction *ITrunc = dyn_cast<Instruction>(Trunc)) {
    // Insert it just after the definition.
    ITrunc->moveAfter(ExtOpnd);
    if (Truncs)
      Truncs->push_back(ITrunc);
  }

  TPT.replaceAllUsesWith(ExtOpnd, Trunc);
  // Restore the operand of Ext (which has been replaced by the previous call
  // to replaceAllUsesWith) to avoid creating a cycle trunc <-> sext.
  TPT.setOperand(Ext, 0, ExtOpnd);
}

// Get through the Instruction:
// 1. Update its type.
// 2. Replace the uses of Ext by Inst.
// 3. Extend each operand that needs to be extended.

// Remember the original type of the instruction before promotion.
// This is useful to know that the high bits are sign extended bits.
addPromotedInst(PromotedInsts, ExtOpnd, IsSExt);
// Step #1.
TPT.mutateType(ExtOpnd, Ext->getType());
// Step #2.
TPT.replaceAllUsesWith(Ext, ExtOpnd);
// Step #3.
Instruction *ExtForOpnd = Ext;

LLVM_DEBUG(dbgs() << "Propagate Ext to operands\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Propagate Ext to operands\n"
; } } while (false);
for (int OpIdx = 0, EndOpIdx = ExtOpnd->getNumOperands(); OpIdx != EndOpIdx;
     ++OpIdx) {
  LLVM_DEBUG(dbgs() << "Operand:\n" << *(ExtOpnd->getOperand(OpIdx)) << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Operand:\n" << *
(ExtOpnd->getOperand(OpIdx)) << '\n'; } } while (false
);
  if (ExtOpnd->getOperand(OpIdx)->getType() == Ext->getType() ||
      !shouldExtOperand(ExtOpnd, OpIdx)) {
    LLVM_DEBUG(dbgs() << "No need to propagate\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "No need to propagate\n"
; } } while (false);
    continue;
  }
  // Check if we can statically extend the operand.
  Value *Opnd = ExtOpnd->getOperand(OpIdx);
  if (const ConstantInt *Cst = dyn_cast<ConstantInt>(Opnd)) {
    LLVM_DEBUG(dbgs() << "Statically extend\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Statically extend\n"; }
 } while (false);
    unsigned BitWidth = Ext->getType()->getIntegerBitWidth();
    APInt CstVal = IsSExt ? Cst->getValue().sext(BitWidth)
                          : Cst->getValue().zext(BitWidth);
    TPT.setOperand(ExtOpnd, OpIdx, ConstantInt::get(Ext->getType(), CstVal));
    continue;
  }
  // UndefValue are typed, so we have to statically sign extend them.
  if (isa<UndefValue>(Opnd)) {
    LLVM_DEBUG(dbgs() << "Statically extend\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Statically extend\n"; }
 } while (false);
    TPT.setOperand(ExtOpnd, OpIdx, UndefValue::get(Ext->getType()));
    continue;
  }

  // Otherwise we have to explicitly sign extend the operand.
  // Check if Ext was reused to extend an operand.
  if (!ExtForOpnd) {
    // If yes, create a new one.
    LLVM_DEBUG(dbgs() << "More operands to ext\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "More operands to ext\n"
; } } while (false);
    Value *ValForExtOpnd = IsSExt ? TPT.createSExt(Ext, Opnd, Ext->getType())
                                  : TPT.createZExt(Ext, Opnd, Ext->getType());
    if (!isa<Instruction>(ValForExtOpnd)) {
      TPT.setOperand(ExtOpnd, OpIdx, ValForExtOpnd);
      continue;
    }
    ExtForOpnd = cast<Instruction>(ValForExtOpnd);
  }
  if (Exts)
    Exts->push_back(ExtForOpnd);
  TPT.setOperand(ExtForOpnd, 0, Opnd);

  // Move the sign extension before the insertion point.
  TPT.moveBefore(ExtForOpnd, ExtOpnd);
  TPT.setOperand(ExtOpnd, OpIdx, ExtForOpnd);
  CreatedInstsCost += !TLI.isExtFree(ExtForOpnd);
  // If more sext are required, new instructions will have to be created.
  ExtForOpnd = nullptr;
}
if (ExtForOpnd == Ext) {
  LLVM_DEBUG(dbgs() << "Extension is useless now\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Extension is useless now\n"
; } } while (false);
  TPT.eraseInstruction(Ext);
}
return ExtOpnd;
4552}

4554/// Check whether or not promoting an instruction to a wider type is profitable.
4555/// \p NewCost gives the cost of extension instructions created by the
4556/// promotion.
4557/// \p OldCost gives the cost of extension instructions before the promotion
4558/// plus the number of instructions that have been
4559/// matched in the addressing mode the promotion.
4560/// \p PromotedOperand is the value that has been promoted.
4561/// \return True if the promotion is profitable, false otherwise.
4562bool AddressingModeMatcher::isPromotionProfitable(
  unsigned NewCost, unsigned OldCost, Value *PromotedOperand) const {
LLVM_DEBUG(dbgs() << "OldCost: " << OldCost << "\tNewCost: " << NewCostdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "OldCost: " << OldCost
 << "\tNewCost: " << NewCost << '\n'; } } while
 (false)
                  << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "OldCost: " << OldCost
 << "\tNewCost: " << NewCost << '\n'; } } while
 (false);
// The cost of the new extensions is greater than the cost of the
// old extension plus what we folded.
// This is not profitable.
if (NewCost > OldCost)
  return false;
if (NewCost < OldCost)
  return true;
// The promotion is neutral but it may help folding the sign extension in
// loads for instance.
// Check that we did not create an illegal instruction.
return isPromotedInstructionLegal(TLI, DL, PromotedOperand);
4577}

4579/// Given an instruction or constant expr, see if we can fold the operation
4580/// into the addressing mode. If so, update the addressing mode and return
4581/// true, otherwise return false without modifying AddrMode.
4582/// If \p MovedAway is not NULL, it contains the information of whether or
4583/// not AddrInst has to be folded into the addressing mode on success.
4584/// If \p MovedAway == true, \p AddrInst will not be part of the addressing
4585/// because it has been moved away.
4586/// Thus AddrInst must not be added in the matched instructions.
4587/// This state can happen when AddrInst is a sext, since it may be moved away.
4588/// Therefore, AddrInst may not be valid when MovedAway is true and it must
4589/// not be referenced anymore.
4590bool AddressingModeMatcher::matchOperationAddr(User *AddrInst, unsigned Opcode,
                                             unsigned Depth,
                                             bool *MovedAway) {
// Avoid exponential behavior on extremely deep expression trees.
if (Depth >= 5)
  return false;

// By default, all matched instructions stay in place.
if (MovedAway)
  *MovedAway = false;

switch (Opcode) {
case Instruction::PtrToInt:
  // PtrToInt is always a noop, as we know that the int type is pointer sized.
  return matchAddr(AddrInst->getOperand(0), Depth);
case Instruction::IntToPtr: {
  auto AS = AddrInst->getType()->getPointerAddressSpace();
  auto PtrTy = MVT::getIntegerVT(DL.getPointerSizeInBits(AS));
  // This inttoptr is a no-op if the integer type is pointer sized.
  if (TLI.getValueType(DL, AddrInst->getOperand(0)->getType()) == PtrTy)
    return matchAddr(AddrInst->getOperand(0), Depth);
  return false;
}
case Instruction::BitCast:
  // BitCast is always a noop, and we can handle it as long as it is
  // int->int or pointer->pointer (we don't want int<->fp or something).
  if (AddrInst->getOperand(0)->getType()->isIntOrPtrTy() &&
      // Don't touch identity bitcasts.  These were probably put here by LSR,
      // and we don't want to mess around with them.  Assume it knows what it
      // is doing.
      AddrInst->getOperand(0)->getType() != AddrInst->getType())
    return matchAddr(AddrInst->getOperand(0), Depth);
  return false;
case Instruction::AddrSpaceCast: {
  unsigned SrcAS =
      AddrInst->getOperand(0)->getType()->getPointerAddressSpace();
  unsigned DestAS = AddrInst->getType()->getPointerAddressSpace();
  if (TLI.getTargetMachine().isNoopAddrSpaceCast(SrcAS, DestAS))
    return matchAddr(AddrInst->getOperand(0), Depth);
  return false;
}
case Instruction::Add: {
  // Check to see if we can merge in one operand, then the other.  If so, we
  // win.
  ExtAddrMode BackupAddrMode = AddrMode;
  unsigned OldSize = AddrModeInsts.size();
  // Start a transaction at this point.
  // The LHS may match but not the RHS.
  // Therefore, we need a higher level restoration point to undo partially
  // matched operation.
  TypePromotionTransaction::ConstRestorationPt LastKnownGood =
      TPT.getRestorationPoint();

  // Try to match an integer constant second to increase its chance of ending
  // up in `BaseOffs`, resp. decrease its chance of ending up in `BaseReg`.
  int First = 0, Second = 1;
  if (isa<ConstantInt>(AddrInst->getOperand(First))
    && !isa<ConstantInt>(AddrInst->getOperand(Second)))
      std::swap(First, Second);
  AddrMode.InBounds = false;
  if (matchAddr(AddrInst->getOperand(First), Depth + 1) &&
      matchAddr(AddrInst->getOperand(Second), Depth + 1))
    return true;

  // Restore the old addr mode info.
  AddrMode = BackupAddrMode;
  AddrModeInsts.resize(OldSize);
  TPT.rollback(LastKnownGood);

  // Otherwise this was over-aggressive.  Try merging operands in the opposite
  // order.
  if (matchAddr(AddrInst->getOperand(Second), Depth + 1) &&
      matchAddr(AddrInst->getOperand(First), Depth + 1))
    return true;

  // Otherwise we definitely can't merge the ADD in.
  AddrMode = BackupAddrMode;
  AddrModeInsts.resize(OldSize);
  TPT.rollback(LastKnownGood);
  break;
}
// case Instruction::Or:
//  TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
// break;
case Instruction::Mul:
case Instruction::Shl: {
  // Can only handle X*C and X << C.
  AddrMode.InBounds = false;
  ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
  if (!RHS || RHS->getBitWidth() > 64)
    return false;
  int64_t Scale = Opcode == Instruction::Shl
                      ? 1LL << RHS->getLimitedValue(RHS->getBitWidth() - 1)
                      : RHS->getSExtValue();

  return matchScaledValue(AddrInst->getOperand(0), Scale, Depth);
}
case Instruction::GetElementPtr: {
  // Scan the GEP.  We check it if it contains constant offsets and at most
  // one variable offset.
  int VariableOperand = -1;
  unsigned VariableScale = 0;

  int64_t ConstantOffset = 0;
  gep_type_iterator GTI = gep_type_begin(AddrInst);
  for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) {
    if (StructType *STy = GTI.getStructTypeOrNull()) {
      const StructLayout *SL = DL.getStructLayout(STy);
      unsigned Idx =
          cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue();
      ConstantOffset += SL->getElementOffset(Idx);
    } else {
      TypeSize TS = DL.getTypeAllocSize(GTI.getIndexedType());
      if (TS.isNonZero()) {
        // The optimisations below currently only work for fixed offsets.
        if (TS.isScalable())
          return false;
        int64_t TypeSize = TS.getFixedValue();
        if (ConstantInt *CI =
                dyn_cast<ConstantInt>(AddrInst->getOperand(i))) {
          const APInt &CVal = CI->getValue();
          if (CVal.getSignificantBits() <= 64) {
            ConstantOffset += CVal.getSExtValue() * TypeSize;
            continue;
          }
        }
        // We only allow one variable index at the moment.
        if (VariableOperand != -1)
          return false;

        // Remember the variable index.
        VariableOperand = i;
        VariableScale = TypeSize;
      }
    }
  }

  // A common case is for the GEP to only do a constant offset.  In this case,
  // just add it to the disp field and check validity.
  if (VariableOperand == -1) {
    AddrMode.BaseOffs += ConstantOffset;
    if (matchAddr(AddrInst->getOperand(0), Depth + 1)) {
        if (!cast<GEPOperator>(AddrInst)->isInBounds())
          AddrMode.InBounds = false;
        return true;
    }
    AddrMode.BaseOffs -= ConstantOffset;

    if (EnableGEPOffsetSplit && isa<GetElementPtrInst>(AddrInst) &&
        TLI.shouldConsiderGEPOffsetSplit() && Depth == 0 &&
        ConstantOffset > 0) {
        // Record GEPs with non-zero offsets as candidates for splitting in
        // the event that the offset cannot fit into the r+i addressing mode.
        // Simple and common case that only one GEP is used in calculating the
        // address for the memory access.
        Value *Base = AddrInst->getOperand(0);
        auto *BaseI = dyn_cast<Instruction>(Base);
        auto *GEP = cast<GetElementPtrInst>(AddrInst);
        if (isa<Argument>(Base) || isa<GlobalValue>(Base) ||
            (BaseI && !isa<CastInst>(BaseI) &&
             !isa<GetElementPtrInst>(BaseI))) {
          // Make sure the parent block allows inserting non-PHI instructions
          // before the terminator.
          BasicBlock *Parent = BaseI ? BaseI->getParent()
                                     : &GEP->getFunction()->getEntryBlock();
          if (!Parent->getTerminator()->isEHPad())
          LargeOffsetGEP = std::make_pair(GEP, ConstantOffset);
        }
    }

    return false;
  }

  // Save the valid addressing mode in case we can't match.
  ExtAddrMode BackupAddrMode = AddrMode;
  unsigned OldSize = AddrModeInsts.size();

  // See if the scale and offset amount is valid for this target.
  AddrMode.BaseOffs += ConstantOffset;
  if (!cast<GEPOperator>(AddrInst)->isInBounds())
    AddrMode.InBounds = false;

  // Match the base operand of the GEP.
  if (!matchAddr(AddrInst->getOperand(0), Depth + 1)) {
    // If it couldn't be matched, just stuff the value in a register.
    if (AddrMode.HasBaseReg) {
      AddrMode = BackupAddrMode;
      AddrModeInsts.resize(OldSize);
      return false;
    }
    AddrMode.HasBaseReg = true;
    AddrMode.BaseReg = AddrInst->getOperand(0);
  }

  // Match the remaining variable portion of the GEP.
  if (!matchScaledValue(AddrInst->getOperand(VariableOperand), VariableScale,
                        Depth)) {
    // If it couldn't be matched, try stuffing the base into a register
    // instead of matching it, and retrying the match of the scale.
    AddrMode = BackupAddrMode;
    AddrModeInsts.resize(OldSize);
    if (AddrMode.HasBaseReg)
      return false;
    AddrMode.HasBaseReg = true;
    AddrMode.BaseReg = AddrInst->getOperand(0);
    AddrMode.BaseOffs += ConstantOffset;
    if (!matchScaledValue(AddrInst->getOperand(VariableOperand),
                          VariableScale, Depth)) {
      // If even that didn't work, bail.
      AddrMode = BackupAddrMode;
      AddrModeInsts.resize(OldSize);
      return false;
    }
  }

  return true;
}
case Instruction::SExt:
case Instruction::ZExt: {
  Instruction *Ext = dyn_cast<Instruction>(AddrInst);
  if (!Ext)
    return false;

  // Try to move this ext out of the way of the addressing mode.
  // Ask for a method for doing so.
  TypePromotionHelper::Action TPH =
      TypePromotionHelper::getAction(Ext, InsertedInsts, TLI, PromotedInsts);
  if (!TPH)
    return false;

  TypePromotionTransaction::ConstRestorationPt LastKnownGood =
      TPT.getRestorationPoint();
  unsigned CreatedInstsCost = 0;
  unsigned ExtCost = !TLI.isExtFree(Ext);
  Value *PromotedOperand =
      TPH(Ext, TPT, PromotedInsts, CreatedInstsCost, nullptr, nullptr, TLI);
  // SExt has been moved away.
  // Thus either it will be rematched later in the recursive calls or it is
  // gone. Anyway, we must not fold it into the addressing mode at this point.
  // E.g.,
  // op = add opnd, 1
  // idx = ext op
  // addr = gep base, idx
  // is now:
  // promotedOpnd = ext opnd            <- no match here
  // op = promoted_add promotedOpnd, 1  <- match (later in recursive calls)
  // addr = gep base, op                <- match
  if (MovedAway)
    *MovedAway = true;

  assert(PromotedOperand &&(static_cast <bool> (PromotedOperand && "TypePromotionHelper should have filtered out those cases"
) ? void (0) : __assert_fail ("PromotedOperand && \"TypePromotionHelper should have filtered out those cases\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 4841, __extension__ __PRETTY_FUNCTION__
))
         "TypePromotionHelper should have filtered out those cases")(static_cast <bool> (PromotedOperand && "TypePromotionHelper should have filtered out those cases"
) ? void (0) : __assert_fail ("PromotedOperand && \"TypePromotionHelper should have filtered out those cases\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 4841, __extension__ __PRETTY_FUNCTION__
));

  ExtAddrMode BackupAddrMode = AddrMode;
  unsigned OldSize = AddrModeInsts.size();

  if (!matchAddr(PromotedOperand, Depth) ||
      // The total of the new cost is equal to the cost of the created
      // instructions.
      // The total of the old cost is equal to the cost of the extension plus
      // what we have saved in the addressing mode.
      !isPromotionProfitable(CreatedInstsCost,
                             ExtCost + (AddrModeInsts.size() - OldSize),
                             PromotedOperand)) {
    AddrMode = BackupAddrMode;
    AddrModeInsts.resize(OldSize);
    LLVM_DEBUG(dbgs() << "Sign extension does not pay off: rollback\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Sign extension does not pay off: rollback\n"
; } } while (false);
    TPT.rollback(LastKnownGood);
    return false;
  }
  return true;
}
}
return false;
4864}

4866/// If we can, try to add the value of 'Addr' into the current addressing mode.
4867/// If Addr can't be added to AddrMode this returns false and leaves AddrMode
4868/// unmodified. This assumes that Addr is either a pointer type or intptr_t
4869/// for the target.
4870///
4871bool AddressingModeMatcher::matchAddr(Value *Addr, unsigned Depth) {
// Start a transaction at this point that we will rollback if the matching
// fails.
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
    TPT.getRestorationPoint();
if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) {
  if (CI->getValue().isSignedIntN(64)) {
    // Fold in immediates if legal for the target.
    AddrMode.BaseOffs += CI->getSExtValue();
    if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
      return true;
    AddrMode.BaseOffs -= CI->getSExtValue();
  }
} else if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) {
  // If this is a global variable, try to fold it into the addressing mode.
  if (!AddrMode.BaseGV) {
    AddrMode.BaseGV = GV;
    if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
      return true;
    AddrMode.BaseGV = nullptr;
  }
} else if (Instruction *I = dyn_cast<Instruction>(Addr)) {
  ExtAddrMode BackupAddrMode = AddrMode;
  unsigned OldSize = AddrModeInsts.size();

  // Check to see if it is possible to fold this operation.
  bool MovedAway = false;
  if (matchOperationAddr(I, I->getOpcode(), Depth, &MovedAway)) {
    // This instruction may have been moved away. If so, there is nothing
    // to check here.
    if (MovedAway)
      return true;
    // Okay, it's possible to fold this.  Check to see if it is actually
    // *profitable* to do so.  We use a simple cost model to avoid increasing
    // register pressure too much.
    if (I->hasOneUse() ||
        isProfitableToFoldIntoAddressingMode(I, BackupAddrMode, AddrMode)) {
      AddrModeInsts.push_back(I);
      return true;
    }

    // It isn't profitable to do this, roll back.
    AddrMode = BackupAddrMode;
    AddrModeInsts.resize(OldSize);
    TPT.rollback(LastKnownGood);
  }
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
  if (matchOperationAddr(CE, CE->getOpcode(), Depth))
    return true;
  TPT.rollback(LastKnownGood);
} else if (isa<ConstantPointerNull>(Addr)) {
  // Null pointer gets folded without affecting the addressing mode.
  return true;
}

// Worse case, the target should support [reg] addressing modes. :)
if (!AddrMode.HasBaseReg) {
  AddrMode.HasBaseReg = true;
  AddrMode.BaseReg = Addr;
  // Still check for legality in case the target supports [imm] but not [i+r].
  if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
    return true;
  AddrMode.HasBaseReg = false;
  AddrMode.BaseReg = nullptr;
}

// If the base register is already taken, see if we can do [r+r].
if (AddrMode.Scale == 0) {
  AddrMode.Scale = 1;
  AddrMode.ScaledReg = Addr;
  if (TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace))
    return true;
  AddrMode.Scale = 0;
  AddrMode.ScaledReg = nullptr;
}
// Couldn't match.
TPT.rollback(LastKnownGood);
return false;
4949}

4951/// Check to see if all uses of OpVal by the specified inline asm call are due
4952/// to memory operands. If so, return true, otherwise return false.
4953static bool IsOperandAMemoryOperand(CallInst *CI, InlineAsm *IA, Value *OpVal,
                                  const TargetLowering &TLI,
                                  const TargetRegisterInfo &TRI) {
const Function *F = CI->getFunction();
TargetLowering::AsmOperandInfoVector TargetConstraints =
    TLI.ParseConstraints(F->getParent()->getDataLayout(), &TRI, *CI);

for (TargetLowering::AsmOperandInfo &OpInfo : TargetConstraints) {
  // Compute the constraint code and ConstraintType to use.
  TLI.ComputeConstraintToUse(OpInfo, SDValue());

  // If this asm operand is our Value*, and if it isn't an indirect memory
  // operand, we can't fold it!  TODO: Also handle C_Address?
  if (OpInfo.CallOperandVal == OpVal &&
      (OpInfo.ConstraintType != TargetLowering::C_Memory ||
       !OpInfo.isIndirect))
    return false;
}

return true;
4973}

4975/// Recursively walk all the uses of I until we find a memory use.
4976/// If we find an obviously non-foldable instruction, return true.
4977/// Add accessed addresses and types to MemoryUses.
4978static bool FindAllMemoryUses(
  Instruction *I, SmallVectorImpl<std::pair<Use *, Type *>> &MemoryUses,
  SmallPtrSetImpl<Instruction *> &ConsideredInsts, const TargetLowering &TLI,
  const TargetRegisterInfo &TRI, bool OptSize, ProfileSummaryInfo *PSI,
  BlockFrequencyInfo *BFI, unsigned &SeenInsts) {
// If we already considered this instruction, we're done.
if (!ConsideredInsts.insert(I).second)
  return false;

// If this is an obviously unfoldable instruction, bail out.
if (!MightBeFoldableInst(I))
  return true;

// Loop over all the uses, recursively processing them.
for (Use &U : I->uses()) {
  // Conservatively return true if we're seeing a large number or a deep chain
  // of users. This avoids excessive compilation times in pathological cases.
  if (SeenInsts++ >= MaxAddressUsersToScan)
    return true;

  Instruction *UserI = cast<Instruction>(U.getUser());
  if (LoadInst *LI = dyn_cast<LoadInst>(UserI)) {
    MemoryUses.push_back({&U, LI->getType()});
    continue;
  }

  if (StoreInst *SI = dyn_cast<StoreInst>(UserI)) {
    if (U.getOperandNo() != StoreInst::getPointerOperandIndex())
      return true; // Storing addr, not into addr.
    MemoryUses.push_back({&U, SI->getValueOperand()->getType()});
    continue;
  }

  if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(UserI)) {
    if (U.getOperandNo() != AtomicRMWInst::getPointerOperandIndex())
      return true; // Storing addr, not into addr.
    MemoryUses.push_back({&U, RMW->getValOperand()->getType()});
    continue;
  }

  if (AtomicCmpXchgInst *CmpX = dyn_cast<AtomicCmpXchgInst>(UserI)) {
    if (U.getOperandNo() != AtomicCmpXchgInst::getPointerOperandIndex())
      return true; // Storing addr, not into addr.
    MemoryUses.push_back({&U, CmpX->getCompareOperand()->getType()});
    continue;
  }

  if (CallInst *CI = dyn_cast<CallInst>(UserI)) {
    if (CI->hasFnAttr(Attribute::Cold)) {
      // If this is a cold call, we can sink the addressing calculation into
      // the cold path.  See optimizeCallInst
      bool OptForSize =
          OptSize || llvm::shouldOptimizeForSize(CI->getParent(), PSI, BFI);
      if (!OptForSize)
        continue;
    }

    InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledOperand());
    if (!IA)
      return true;

    // If this is a memory operand, we're cool, otherwise bail out.
    if (!IsOperandAMemoryOperand(CI, IA, I, TLI, TRI))
      return true;
    continue;
  }

  if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TLI, TRI, OptSize,
                        PSI, BFI, SeenInsts))
    return true;
}

return false;
5051}

5053static bool FindAllMemoryUses(
  Instruction *I, SmallVectorImpl<std::pair<Use *, Type *>> &MemoryUses,
  const TargetLowering &TLI, const TargetRegisterInfo &TRI, bool OptSize,
  ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI) {
unsigned SeenInsts = 0;
SmallPtrSet<Instruction *, 16> ConsideredInsts;
return FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TLI, TRI, OptSize,
                         PSI, BFI, SeenInsts);
5061}


5064/// Return true if Val is already known to be live at the use site that we're
5065/// folding it into. If so, there is no cost to include it in the addressing
5066/// mode. KnownLive1 and KnownLive2 are two values that we know are live at the
5067/// instruction already.
5068bool AddressingModeMatcher::valueAlreadyLiveAtInst(Value *Val,
                                                 Value *KnownLive1,
                                                 Value *KnownLive2) {
// If Val is either of the known-live values, we know it is live!
if (Val == nullptr || Val == KnownLive1 || Val == KnownLive2)
  return true;

// All values other than instructions and arguments (e.g. constants) are live.
if (!isa<Instruction>(Val) && !isa<Argument>(Val))
  return true;

// If Val is a constant sized alloca in the entry block, it is live, this is
// true because it is just a reference to the stack/frame pointer, which is
// live for the whole function.
if (AllocaInst *AI = dyn_cast<AllocaInst>(Val))
  if (AI->isStaticAlloca())
    return true;

// Check to see if this value is already used in the memory instruction's
// block.  If so, it's already live into the block at the very least, so we
// can reasonably fold it.
return Val->isUsedInBasicBlock(MemoryInst->getParent());
5090}

5092/// It is possible for the addressing mode of the machine to fold the specified
5093/// instruction into a load or store that ultimately uses it.
5094/// However, the specified instruction has multiple uses.
5095/// Given this, it may actually increase register pressure to fold it
5096/// into the load. For example, consider this code:
5097///
5098///     X = ...
5099///     Y = X+1
5100///     use(Y)   -> nonload/store
5101///     Z = Y+1
5102///     load Z
5103///
5104/// In this case, Y has multiple uses, and can be folded into the load of Z
5105/// (yielding load [X+2]).  However, doing this will cause both "X" and "X+1" to
5106/// be live at the use(Y) line.  If we don't fold Y into load Z, we use one
5107/// fewer register.  Since Y can't be folded into "use(Y)" we don't increase the
5108/// number of computations either.
5109///
5110/// Note that this (like most of CodeGenPrepare) is just a rough heuristic.  If
5111/// X was live across 'load Z' for other reasons, we actually *would* want to
5112/// fold the addressing mode in the Z case.  This would make Y die earlier.
5113bool AddressingModeMatcher::isProfitableToFoldIntoAddressingMode(
  Instruction *I, ExtAddrMode &AMBefore, ExtAddrMode &AMAfter) {
if (IgnoreProfitability)
  return true;

// AMBefore is the addressing mode before this instruction was folded into it,
// and AMAfter is the addressing mode after the instruction was folded.  Get
// the set of registers referenced by AMAfter and subtract out those
// referenced by AMBefore: this is the set of values which folding in this
// address extends the lifetime of.
//
// Note that there are only two potential values being referenced here,
// BaseReg and ScaleReg (global addresses are always available, as are any
// folded immediates).
Value *BaseReg = AMAfter.BaseReg, *ScaledReg = AMAfter.ScaledReg;

// If the BaseReg or ScaledReg was referenced by the previous addrmode, their
// lifetime wasn't extended by adding this instruction.
if (valueAlreadyLiveAtInst(BaseReg, AMBefore.BaseReg, AMBefore.ScaledReg))
  BaseReg = nullptr;
if (valueAlreadyLiveAtInst(ScaledReg, AMBefore.BaseReg, AMBefore.ScaledReg))
  ScaledReg = nullptr;

// If folding this instruction (and it's subexprs) didn't extend any live
// ranges, we're ok with it.
if (!BaseReg && !ScaledReg)
  return true;

// If all uses of this instruction can have the address mode sunk into them,
// we can remove the addressing mode and effectively trade one live register
// for another (at worst.)  In this context, folding an addressing mode into
// the use is just a particularly nice way of sinking it.
SmallVector<std::pair<Use *, Type *>, 16> MemoryUses;
if (FindAllMemoryUses(I, MemoryUses, TLI, TRI, OptSize, PSI, BFI))
  return false; // Has a non-memory, non-foldable use!

// Now that we know that all uses of this instruction are part of a chain of
// computation involving only operations that could theoretically be folded
// into a memory use, loop over each of these memory operation uses and see
// if they could  *actually* fold the instruction.  The assumption is that
// addressing modes are cheap and that duplicating the computation involved
// many times is worthwhile, even on a fastpath. For sinking candidates
// (i.e. cold call sites), this serves as a way to prevent excessive code
// growth since most architectures have some reasonable small and fast way to
// compute an effective address.  (i.e LEA on x86)
SmallVector<Instruction *, 32> MatchedAddrModeInsts;
for (const std::pair<Use *, Type *> &Pair : MemoryUses) {
  Value *Address = Pair.first->get();
  Instruction *UserI = cast<Instruction>(Pair.first->getUser());
  Type *AddressAccessTy = Pair.second;
  unsigned AS = Address->getType()->getPointerAddressSpace();

  // Do a match against the root of this address, ignoring profitability. This
  // will tell us if the addressing mode for the memory operation will
  // *actually* cover the shared instruction.
  ExtAddrMode Result;
  std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr,
                                                                    0);
  TypePromotionTransaction::ConstRestorationPt LastKnownGood =
      TPT.getRestorationPoint();
  AddressingModeMatcher Matcher(MatchedAddrModeInsts, TLI, TRI, LI, getDTFn,
                                AddressAccessTy, AS, UserI, Result,
                                InsertedInsts, PromotedInsts, TPT,
                                LargeOffsetGEP, OptSize, PSI, BFI);
  Matcher.IgnoreProfitability = true;
  bool Success = Matcher.matchAddr(Address, 0);
  (void)Success;
  assert(Success && "Couldn't select *anything*?")(static_cast <bool> (Success && "Couldn't select *anything*?"
) ? void (0) : __assert_fail ("Success && \"Couldn't select *anything*?\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 5180, __extension__ __PRETTY_FUNCTION__
));

  // The match was to check the profitability, the changes made are not
  // part of the original matcher. Therefore, they should be dropped
  // otherwise the original matcher will not present the right state.
  TPT.rollback(LastKnownGood);

  // If the match didn't cover I, then it won't be shared by it.
  if (!is_contained(MatchedAddrModeInsts, I))
    return false;

  MatchedAddrModeInsts.clear();
}

return true;
5195}

5197/// Return true if the specified values are defined in a
5198/// different basic block than BB.
5199static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
if (Instruction *I = dyn_cast<Instruction>(V))
  return I->getParent() != BB;
return false;
5203}

5205/// Sink addressing mode computation immediate before MemoryInst if doing so
5206/// can be done without increasing register pressure.  The need for the
5207/// register pressure constraint means this can end up being an all or nothing
5208/// decision for all uses of the same addressing computation.
5209///
5210/// Load and Store Instructions often have addressing modes that can do
5211/// significant amounts of computation. As such, instruction selection will try
5212/// to get the load or store to do as much computation as possible for the
5213/// program. The problem is that isel can only see within a single block. As
5214/// such, we sink as much legal addressing mode work into the block as possible.
5215///
5216/// This method is used to optimize both load/store and inline asms with memory
5217/// operands.  It's also used to sink addressing computations feeding into cold
5218/// call sites into their (cold) basic block.
5219///
5220/// The motivation for handling sinking into cold blocks is that doing so can
5221/// both enable other address mode sinking (by satisfying the register pressure
5222/// constraint above), and reduce register pressure globally (by removing the
5223/// addressing mode computation from the fast path entirely.).
5224bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
                                      Type *AccessTy, unsigned AddrSpace) {
Value *Repl = Addr;

// Try to collapse single-value PHI nodes.  This is necessary to undo
// unprofitable PRE transformations.
SmallVector<Value *, 8> worklist;
SmallPtrSet<Value *, 16> Visited;
worklist.push_back(Addr);

// Use a worklist to iteratively look through PHI and select nodes, and
// ensure that the addressing mode obtained from the non-PHI/select roots of
// the graph are compatible.
bool PhiOrSelectSeen = false;
SmallVector<Instruction *, 16> AddrModeInsts;
const SimplifyQuery SQ(*DL, TLInfo);
AddressingModeCombiner AddrModes(SQ, Addr);
TypePromotionTransaction TPT(RemovedInsts);
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
    TPT.getRestorationPoint();
while (!worklist.empty()) {
  Value *V = worklist.pop_back_val();

  // We allow traversing cyclic Phi nodes.
  // In case of success after this loop we ensure that traversing through
  // Phi nodes ends up with all cases to compute address of the form
  //    BaseGV + Base + Scale * Index + Offset
  // where Scale and Offset are constans and BaseGV, Base and Index
  // are exactly the same Values in all cases.
  // It means that BaseGV, Scale and Offset dominate our memory instruction
  // and have the same value as they had in address computation represented
  // as Phi. So we can safely sink address computation to memory instruction.
  if (!Visited.insert(V).second)
    continue;

  // For a PHI node, push all of its incoming values.
  if (PHINode *P = dyn_cast<PHINode>(V)) {
    append_range(worklist, P->incoming_values());
    PhiOrSelectSeen = true;
    continue;
  }
  // Similar for select.
  if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
    worklist.push_back(SI->getFalseValue());
    worklist.push_back(SI->getTrueValue());
    PhiOrSelectSeen = true;
    continue;
  }

  // For non-PHIs, determine the addressing mode being computed.  Note that
  // the result may differ depending on what other uses our candidate
  // addressing instructions might have.
  AddrModeInsts.clear();
  std::pair<AssertingVH<GetElementPtrInst>, int64_t> LargeOffsetGEP(nullptr,
                                                                    0);
  // Defer the query (and possible computation of) the dom tree to point of
  // actual use.  It's expected that most address matches don't actually need
  // the domtree.
  auto getDTFn = [MemoryInst, this]() -> const DominatorTree & {
    Function *F = MemoryInst->getParent()->getParent();
    return this->getDT(*F);
  };
  ExtAddrMode NewAddrMode = AddressingModeMatcher::Match(
      V, AccessTy, AddrSpace, MemoryInst, AddrModeInsts, *TLI, *LI, getDTFn,
      *TRI, InsertedInsts, PromotedInsts, TPT, LargeOffsetGEP, OptSize, PSI,
      BFI.get());

  GetElementPtrInst *GEP = LargeOffsetGEP.first;
  if (GEP && !NewGEPBases.count(GEP)) {
    // If splitting the underlying data structure can reduce the offset of a
    // GEP, collect the GEP.  Skip the GEPs that are the new bases of
    // previously split data structures.
    LargeOffsetGEPMap[GEP->getPointerOperand()].push_back(LargeOffsetGEP);
    LargeOffsetGEPID.insert(std::make_pair(GEP, LargeOffsetGEPID.size()));
  }

  NewAddrMode.OriginalValue = V;
  if (!AddrModes.addNewAddrMode(NewAddrMode))
    break;
}

// Try to combine the AddrModes we've collected. If we couldn't collect any,
// or we have multiple but either couldn't combine them or combining them
// wouldn't do anything useful, bail out now.
if (!AddrModes.combineAddrModes()) {
  TPT.rollback(LastKnownGood);
  return false;
}
bool Modified = TPT.commit();

// Get the combined AddrMode (or the only AddrMode, if we only had one).
ExtAddrMode AddrMode = AddrModes.getAddrMode();

// If all the instructions matched are already in this BB, don't do anything.
// If we saw a Phi node then it is not local definitely, and if we saw a
// select then we want to push the address calculation past it even if it's
// already in this BB.
if (!PhiOrSelectSeen && none_of(AddrModeInsts, [&](Value *V) {
      return IsNonLocalValue(V, MemoryInst->getParent());
    })) {
  LLVM_DEBUG(dbgs() << "CGP: Found      local addrmode: " << AddrModedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Found      local addrmode: "
 << AddrMode << "\n"; } } while (false)
                    << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Found      local addrmode: "
 << AddrMode << "\n"; } } while (false);
  return Modified;
}

// Insert this computation right after this user.  Since our caller is
// scanning from the top of the BB to the bottom, reuse of the expr are
// guaranteed to happen later.
IRBuilder<> Builder(MemoryInst);

// Now that we determined the addressing expression we want to use and know
// that we have to sink it into this block.  Check to see if we have already
// done this for some other load/store instr in this block.  If so, reuse
// the computation.  Before attempting reuse, check if the address is valid
// as it may have been erased.

WeakTrackingVH SunkAddrVH = SunkAddrs[Addr];

Value *SunkAddr = SunkAddrVH.pointsToAliveValue() ? SunkAddrVH : nullptr;
Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
if (SunkAddr) {
  LLVM_DEBUG(dbgs() << "CGP: Reusing nonlocal addrmode: " << AddrModedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Reusing nonlocal addrmode: "
 << AddrMode << " for " << *MemoryInst <<
 "\n"; } } while (false)
                    << " for " << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: Reusing nonlocal addrmode: "
 << AddrMode << " for " << *MemoryInst <<
 "\n"; } } while (false);
  if (SunkAddr->getType() != Addr->getType()) {
    if (SunkAddr->getType()->getPointerAddressSpace() !=
            Addr->getType()->getPointerAddressSpace() &&
        !DL->isNonIntegralPointerType(Addr->getType())) {
      // There are two reasons the address spaces might not match: a no-op
      // addrspacecast, or a ptrtoint/inttoptr pair. Either way, we emit a
      // ptrtoint/inttoptr pair to ensure we match the original semantics.
      // TODO: allow bitcast between different address space pointers with the
      // same size.
      SunkAddr = Builder.CreatePtrToInt(SunkAddr, IntPtrTy, "sunkaddr");
      SunkAddr =
          Builder.CreateIntToPtr(SunkAddr, Addr->getType(), "sunkaddr");
    } else
      SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
  }
} else if (AddrSinkUsingGEPs || (!AddrSinkUsingGEPs.getNumOccurrences() &&
                                 SubtargetInfo->addrSinkUsingGEPs())) {
  // By default, we use the GEP-based method when AA is used later. This
  // prevents new inttoptr/ptrtoint pairs from degrading AA capabilities.
  LLVM_DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrModedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
 << AddrMode << " for " << *MemoryInst <<
 "\n"; } } while (false)
                    << " for " << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
 << AddrMode << " for " << *MemoryInst <<
 "\n"; } } while (false);
  Value *ResultPtr = nullptr, *ResultIndex = nullptr;

  // First, find the pointer.
  if (AddrMode.BaseReg && AddrMode.BaseReg->getType()->isPointerTy()) {
    ResultPtr = AddrMode.BaseReg;
    AddrMode.BaseReg = nullptr;
  }

  if (AddrMode.Scale && AddrMode.ScaledReg->getType()->isPointerTy()) {
    // We can't add more than one pointer together, nor can we scale a
    // pointer (both of which seem meaningless).
    if (ResultPtr || AddrMode.Scale != 1)
      return Modified;

    ResultPtr = AddrMode.ScaledReg;
    AddrMode.Scale = 0;
  }

  // It is only safe to sign extend the BaseReg if we know that the math
  // required to create it did not overflow before we extend it. Since
  // the original IR value was tossed in favor of a constant back when
  // the AddrMode was created we need to bail out gracefully if widths
  // do not match instead of extending it.
  //
  // (See below for code to add the scale.)
  if (AddrMode.Scale) {
    Type *ScaledRegTy = AddrMode.ScaledReg->getType();
    if (cast<IntegerType>(IntPtrTy)->getBitWidth() >
        cast<IntegerType>(ScaledRegTy)->getBitWidth())
      return Modified;
  }

  if (AddrMode.BaseGV) {
    if (ResultPtr)
      return Modified;

    ResultPtr = AddrMode.BaseGV;
  }

  // If the real base value actually came from an inttoptr, then the matcher
  // will look through it and provide only the integer value. In that case,
  // use it here.
  if (!DL->isNonIntegralPointerType(Addr->getType())) {
    if (!ResultPtr && AddrMode.BaseReg) {
      ResultPtr = Builder.CreateIntToPtr(AddrMode.BaseReg, Addr->getType(),
                                         "sunkaddr");
      AddrMode.BaseReg = nullptr;
    } else if (!ResultPtr && AddrMode.Scale == 1) {
      ResultPtr = Builder.CreateIntToPtr(AddrMode.ScaledReg, Addr->getType(),
                                         "sunkaddr");
      AddrMode.Scale = 0;
    }
  }

  if (!ResultPtr && !AddrMode.BaseReg && !AddrMode.Scale &&
      !AddrMode.BaseOffs) {
    SunkAddr = Constant::getNullValue(Addr->getType());
  } else if (!ResultPtr) {
    return Modified;
  } else {
    Type *I8PtrTy =
        Builder.getInt8PtrTy(Addr->getType()->getPointerAddressSpace());
    Type *I8Ty = Builder.getInt8Ty();

    // Start with the base register. Do this first so that subsequent address
    // matching finds it last, which will prevent it from trying to match it
    // as the scaled value in case it happens to be a mul. That would be
    // problematic if we've sunk a different mul for the scale, because then
    // we'd end up sinking both muls.
    if (AddrMode.BaseReg) {
      Value *V = AddrMode.BaseReg;
      if (V->getType() != IntPtrTy)
        V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");

      ResultIndex = V;
    }

    // Add the scale value.
    if (AddrMode.Scale) {
      Value *V = AddrMode.ScaledReg;
      if (V->getType() == IntPtrTy) {
        // done.
      } else {
        assert(cast<IntegerType>(IntPtrTy)->getBitWidth() <(static_cast <bool> (cast<IntegerType>(IntPtrTy)->
getBitWidth() < cast<IntegerType>(V->getType())->
getBitWidth() && "We can't transform if ScaledReg is too narrow"
) ? void (0) : __assert_fail ("cast<IntegerType>(IntPtrTy)->getBitWidth() < cast<IntegerType>(V->getType())->getBitWidth() && \"We can't transform if ScaledReg is too narrow\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 5453, __extension__ __PRETTY_FUNCTION__
))
                   cast<IntegerType>(V->getType())->getBitWidth() &&(static_cast <bool> (cast<IntegerType>(IntPtrTy)->
getBitWidth() < cast<IntegerType>(V->getType())->
getBitWidth() && "We can't transform if ScaledReg is too narrow"
) ? void (0) : __assert_fail ("cast<IntegerType>(IntPtrTy)->getBitWidth() < cast<IntegerType>(V->getType())->getBitWidth() && \"We can't transform if ScaledReg is too narrow\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 5453, __extension__ __PRETTY_FUNCTION__
))
               "We can't transform if ScaledReg is too narrow")(static_cast <bool> (cast<IntegerType>(IntPtrTy)->
getBitWidth() < cast<IntegerType>(V->getType())->
getBitWidth() && "We can't transform if ScaledReg is too narrow"
) ? void (0) : __assert_fail ("cast<IntegerType>(IntPtrTy)->getBitWidth() < cast<IntegerType>(V->getType())->getBitWidth() && \"We can't transform if ScaledReg is too narrow\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 5453, __extension__ __PRETTY_FUNCTION__
));
        V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
      }

      if (AddrMode.Scale != 1)
        V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
                              "sunkaddr");
      if (ResultIndex)
        ResultIndex = Builder.CreateAdd(ResultIndex, V, "sunkaddr");
      else
        ResultIndex = V;
    }

    // Add in the Base Offset if present.
    if (AddrMode.BaseOffs) {
      Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
      if (ResultIndex) {
        // We need to add this separately from the scale above to help with
        // SDAG consecutive load/store merging.
        if (ResultPtr->getType() != I8PtrTy)
          ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
        ResultPtr = Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex,
                                      "sunkaddr", AddrMode.InBounds);
      }

      ResultIndex = V;
    }

    if (!ResultIndex) {
      SunkAddr = ResultPtr;
    } else {
      if (ResultPtr->getType() != I8PtrTy)
        ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
      SunkAddr = Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr",
                                   AddrMode.InBounds);
    }

    if (SunkAddr->getType() != Addr->getType()) {
      if (SunkAddr->getType()->getPointerAddressSpace() !=
              Addr->getType()->getPointerAddressSpace() &&
          !DL->isNonIntegralPointerType(Addr->getType())) {
        // There are two reasons the address spaces might not match: a no-op
        // addrspacecast, or a ptrtoint/inttoptr pair. Either way, we emit a
        // ptrtoint/inttoptr pair to ensure we match the original semantics.
        // TODO: allow bitcast between different address space pointers with
        // the same size.
        SunkAddr = Builder.CreatePtrToInt(SunkAddr, IntPtrTy, "sunkaddr");
        SunkAddr =
            Builder.CreateIntToPtr(SunkAddr, Addr->getType(), "sunkaddr");
      } else
        SunkAddr = Builder.CreatePointerCast(SunkAddr, Addr->getType());
    }
  }
} else {
  // We'd require a ptrtoint/inttoptr down the line, which we can't do for
  // non-integral pointers, so in that case bail out now.
  Type *BaseTy = AddrMode.BaseReg ? AddrMode.BaseReg->getType() : nullptr;
  Type *ScaleTy = AddrMode.Scale ? AddrMode.ScaledReg->getType() : nullptr;
  PointerType *BasePtrTy = dyn_cast_or_null<PointerType>(BaseTy);
  PointerType *ScalePtrTy = dyn_cast_or_null<PointerType>(ScaleTy);
  if (DL->isNonIntegralPointerType(Addr->getType()) ||
      (BasePtrTy && DL->isNonIntegralPointerType(BasePtrTy)) ||
      (ScalePtrTy && DL->isNonIntegralPointerType(ScalePtrTy)) ||
      (AddrMode.BaseGV &&
       DL->isNonIntegralPointerType(AddrMode.BaseGV->getType())))
    return Modified;

  LLVM_DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrModedo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
 << AddrMode << " for " << *MemoryInst <<
 "\n"; } } while (false)
                    << " for " << *MemoryInst << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "CGP: SINKING nonlocal addrmode: "
 << AddrMode << " for " << *MemoryInst <<
 "\n"; } } while (false);
  Type *IntPtrTy = DL->getIntPtrType(Addr->getType());
  Value *Result = nullptr;

  // Start with the base register. Do this first so that subsequent address
  // matching finds it last, which will prevent it from trying to match it
  // as the scaled value in case it happens to be a mul. That would be
  // problematic if we've sunk a different mul for the scale, because then
  // we'd end up sinking both muls.
  if (AddrMode.BaseReg) {
    Value *V = AddrMode.BaseReg;
    if (V->getType()->isPointerTy())
      V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
    if (V->getType() != IntPtrTy)
      V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
    Result = V;
  }

  // Add the scale value.
  if (AddrMode.Scale) {
    Value *V = AddrMode.ScaledReg;
    if (V->getType() == IntPtrTy) {
      // done.
    } else if (V->getType()->isPointerTy()) {
      V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
    } else if (cast<IntegerType>(IntPtrTy)->getBitWidth() <
               cast<IntegerType>(V->getType())->getBitWidth()) {
      V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
    } else {
      // It is only safe to sign extend the BaseReg if we know that the math
      // required to create it did not overflow before we extend it. Since
      // the original IR value was tossed in favor of a constant back when
      // the AddrMode was created we need to bail out gracefully if widths
      // do not match instead of extending it.
      Instruction *I = dyn_cast_or_null<Instruction>(Result);
      if (I && (Result != AddrMode.BaseReg))
        I->eraseFromParent();
      return Modified;
    }
    if (AddrMode.Scale != 1)
      V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
                            "sunkaddr");
    if (Result)
      Result = Builder.CreateAdd(Result, V, "sunkaddr");
    else
      Result = V;
  }

  // Add in the BaseGV if present.
  if (AddrMode.BaseGV) {
    Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr");
    if (Result)
      Result = Builder.CreateAdd(Result, V, "sunkaddr");
    else
      Result = V;
  }

  // Add in the Base Offset if present.
  if (AddrMode.BaseOffs) {
    Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
    if (Result)
      Result = Builder.CreateAdd(Result, V, "sunkaddr");
    else
      Result = V;
  }

  if (!Result)
    SunkAddr = Constant::getNullValue(Addr->getType());
  else
    SunkAddr = Builder.CreateIntToPtr(Result, Addr->getType(), "sunkaddr");
}

MemoryInst->replaceUsesOfWith(Repl, SunkAddr);
// Store the newly computed address into the cache. In the case we reused a
// value, this should be idempotent.
SunkAddrs[Addr] = WeakTrackingVH(SunkAddr);

// If we have no uses, recursively delete the value and all dead instructions
// using it.
if (Repl->use_empty()) {
  resetIteratorIfInvalidatedWhileCalling(CurInstIterator->getParent(), [&]() {
    RecursivelyDeleteTriviallyDeadInstructions(
        Repl, TLInfo, nullptr,
        [&](Value *V) { removeAllAssertingVHReferences(V); });
  });
}
++NumMemoryInsts;
return true;
5609}

5611/// Rewrite GEP input to gather/scatter to enable SelectionDAGBuilder to find
5612/// a uniform base to use for ISD::MGATHER/MSCATTER. SelectionDAGBuilder can
5613/// only handle a 2 operand GEP in the same basic block or a splat constant
5614/// vector. The 2 operands to the GEP must have a scalar pointer and a vector
5615/// index.
5616///
5617/// If the existing GEP has a vector base pointer that is splat, we can look
5618/// through the splat to find the scalar pointer. If we can't find a scalar
5619/// pointer there's nothing we can do.
5620///
5621/// If we have a GEP with more than 2 indices where the middle indices are all
5622/// zeroes, we can replace it with 2 GEPs where the second has 2 operands.
5623///
5624/// If the final index isn't a vector or is a splat, we can emit a scalar GEP
5625/// followed by a GEP with an all zeroes vector index. This will enable
5626/// SelectionDAGBuilder to use the scalar GEP as the uniform base and have a
5627/// zero index.
5628bool CodeGenPrepare::optimizeGatherScatterInst(Instruction *MemoryInst,
                                             Value *Ptr) {
Value *NewAddr;

if (const auto *GEP = dyn_cast<GetElementPtrInst>(Ptr)) {
  // Don't optimize GEPs that don't have indices.
  if (!GEP->hasIndices())
    return false;

  // If the GEP and the gather/scatter aren't in the same BB, don't optimize.
  // FIXME: We should support this by sinking the GEP.
  if (MemoryInst->getParent() != GEP->getParent())
    return false;

  SmallVector<Value *, 2> Ops(GEP->operands());

  bool RewriteGEP = false;

  if (Ops[0]->getType()->isVectorTy()) {
    Ops[0] = getSplatValue(Ops[0]);
    if (!Ops[0])
      return false;
    RewriteGEP = true;
  }

  unsigned FinalIndex = Ops.size() - 1;

  // Ensure all but the last index is 0.
  // FIXME: This isn't strictly required. All that's required is that they are
  // all scalars or splats.
  for (unsigned i = 1; i < FinalIndex; ++i) {
    auto *C = dyn_cast<Constant>(Ops[i]);
    if (!C)
      return false;
    if (isa<VectorType>(C->getType()))
      C = C->getSplatValue();
    auto *CI = dyn_cast_or_null<ConstantInt>(C);
    if (!CI || !CI->isZero())
      return false;
    // Scalarize the index if needed.
    Ops[i] = CI;
  }

  // Try to scalarize the final index.
  if (Ops[FinalIndex]->getType()->isVectorTy()) {
    if (Value *V = getSplatValue(Ops[FinalIndex])) {
      auto *C = dyn_cast<ConstantInt>(V);
      // Don't scalarize all zeros vector.
      if (!C || !C->isZero()) {
        Ops[FinalIndex] = V;
        RewriteGEP = true;
      }
    }
  }

  // If we made any changes or the we have extra operands, we need to generate
  // new instructions.
  if (!RewriteGEP && Ops.size() == 2)
    return false;

  auto NumElts = cast<VectorType>(Ptr->getType())->getElementCount();

  IRBuilder<> Builder(MemoryInst);

  Type *SourceTy = GEP->getSourceElementType();
  Type *ScalarIndexTy = DL->getIndexType(Ops[0]->getType()->getScalarType());

  // If the final index isn't a vector, emit a scalar GEP containing all ops
  // and a vector GEP with all zeroes final index.
  if (!Ops[FinalIndex]->getType()->isVectorTy()) {
    NewAddr = Builder.CreateGEP(SourceTy, Ops[0], ArrayRef(Ops).drop_front());
    auto *IndexTy = VectorType::get(ScalarIndexTy, NumElts);
    auto *SecondTy = GetElementPtrInst::getIndexedType(
        SourceTy, ArrayRef(Ops).drop_front());
    NewAddr =
        Builder.CreateGEP(SecondTy, NewAddr, Constant::getNullValue(IndexTy));
  } else {
    Value *Base = Ops[0];
    Value *Index = Ops[FinalIndex];

    // Create a scalar GEP if there are more than 2 operands.
    if (Ops.size() != 2) {
      // Replace the last index with 0.
      Ops[FinalIndex] = Constant::getNullValue(ScalarIndexTy);
      Base = Builder.CreateGEP(SourceTy, Base, ArrayRef(Ops).drop_front());
      SourceTy = GetElementPtrInst::getIndexedType(
          SourceTy, ArrayRef(Ops).drop_front());
    }

    // Now create the GEP with scalar pointer and vector index.
    NewAddr = Builder.CreateGEP(SourceTy, Base, Index);
  }
} else if (!isa<Constant>(Ptr)) {
  // Not a GEP, maybe its a splat and we can create a GEP to enable
  // SelectionDAGBuilder to use it as a uniform base.
  Value *V = getSplatValue(Ptr);
  if (!V)
    return false;

  auto NumElts = cast<VectorType>(Ptr->getType())->getElementCount();

  IRBuilder<> Builder(MemoryInst);

  // Emit a vector GEP with a scalar pointer and all 0s vector index.
  Type *ScalarIndexTy = DL->getIndexType(V->getType()->getScalarType());
  auto *IndexTy = VectorType::get(ScalarIndexTy, NumElts);
  Type *ScalarTy;
  if (cast<IntrinsicInst>(MemoryInst)->getIntrinsicID() ==
      Intrinsic::masked_gather) {
    ScalarTy = MemoryInst->getType()->getScalarType();
  } else {
    assert(cast<IntrinsicInst>(MemoryInst)->getIntrinsicID() ==(static_cast <bool> (cast<IntrinsicInst>(MemoryInst
)->getIntrinsicID() == Intrinsic::masked_scatter) ? void (
0) : __assert_fail ("cast<IntrinsicInst>(MemoryInst)->getIntrinsicID() == Intrinsic::masked_scatter"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 5740, __extension__ __PRETTY_FUNCTION__
))
           Intrinsic::masked_scatter)(static_cast <bool> (cast<IntrinsicInst>(MemoryInst
)->getIntrinsicID() == Intrinsic::masked_scatter) ? void (
0) : __assert_fail ("cast<IntrinsicInst>(MemoryInst)->getIntrinsicID() == Intrinsic::masked_scatter"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 5740, __extension__ __PRETTY_FUNCTION__
));
    ScalarTy = MemoryInst->getOperand(0)->getType()->getScalarType();
  }
  NewAddr = Builder.CreateGEP(ScalarTy, V, Constant::getNullValue(IndexTy));
} else {
  // Constant, SelectionDAGBuilder knows to check if its a splat.
  return false;
}

MemoryInst->replaceUsesOfWith(Ptr, NewAddr);

// If we have no uses, recursively delete the value and all dead instructions
// using it.
if (Ptr->use_empty())
  RecursivelyDeleteTriviallyDeadInstructions(
      Ptr, TLInfo, nullptr,
      [&](Value *V) { removeAllAssertingVHReferences(V); });

return true;
5759}

5761/// If there are any memory operands, use OptimizeMemoryInst to sink their
5762/// address computing into the block when possible / profitable.
5763bool CodeGenPrepare::optimizeInlineAsmInst(CallInst *CS) {
bool MadeChange = false;

const TargetRegisterInfo *TRI =
    TM->getSubtargetImpl(*CS->getFunction())->getRegisterInfo();
TargetLowering::AsmOperandInfoVector TargetConstraints =
    TLI->ParseConstraints(*DL, TRI, *CS);
unsigned ArgNo = 0;
for (TargetLowering::AsmOperandInfo &OpInfo : TargetConstraints) {
  // Compute the constraint code and ConstraintType to use.
  TLI->ComputeConstraintToUse(OpInfo, SDValue());

  // TODO: Also handle C_Address?
  if (OpInfo.ConstraintType == TargetLowering::C_Memory &&
      OpInfo.isIndirect) {
    Value *OpVal = CS->getArgOperand(ArgNo++);
    MadeChange |= optimizeMemoryInst(CS, OpVal, OpVal->getType(), ~0u);
  } else if (OpInfo.Type == InlineAsm::isInput)
    ArgNo++;
}

return MadeChange;
5785}

5787/// Check if all the uses of \p Val are equivalent (or free) zero or
5788/// sign extensions.
5789static bool hasSameExtUse(Value *Val, const TargetLowering &TLI) {
assert(!Val->use_empty() && "Input must have at least one use")(static_cast <bool> (!Val->use_empty() && "Input must have at least one use"
) ? void (0) : __assert_fail ("!Val->use_empty() && \"Input must have at least one use\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 5790, __extension__ __PRETTY_FUNCTION__
));
const Instruction *FirstUser = cast<Instruction>(*Val->user_begin());
bool IsSExt = isa<SExtInst>(FirstUser);
Type *ExtTy = FirstUser->getType();
for (const User *U : Val->users()) {
  const Instruction *UI = cast<Instruction>(U);
  if ((IsSExt && !isa<SExtInst>(UI)) || (!IsSExt && !isa<ZExtInst>(UI)))
    return false;
  Type *CurTy = UI->getType();
  // Same input and output types: Same instruction after CSE.
  if (CurTy == ExtTy)
    continue;

  // If IsSExt is true, we are in this situation:
  // a = Val
  // b = sext ty1 a to ty2
  // c = sext ty1 a to ty3
  // Assuming ty2 is shorter than ty3, this could be turned into:
  // a = Val
  // b = sext ty1 a to ty2
  // c = sext ty2 b to ty3
  // However, the last sext is not free.
  if (IsSExt)
    return false;

  // This is a ZExt, maybe this is free to extend from one type to another.
  // In that case, we would not account for a different use.
  Type *NarrowTy;
  Type *LargeTy;
  if (ExtTy->getScalarType()->getIntegerBitWidth() >
      CurTy->getScalarType()->getIntegerBitWidth()) {
    NarrowTy = CurTy;
    LargeTy = ExtTy;
  } else {
    NarrowTy = ExtTy;
    LargeTy = CurTy;
  }

  if (!TLI.isZExtFree(NarrowTy, LargeTy))
    return false;
}
// All uses are the same or can be derived from one another for free.
return true;
5833}

5835/// Try to speculatively promote extensions in \p Exts and continue
5836/// promoting through newly promoted operands recursively as far as doing so is
5837/// profitable. Save extensions profitably moved up, in \p ProfitablyMovedExts.
5838/// When some promotion happened, \p TPT contains the proper state to revert
5839/// them.
5840///
5841/// \return true if some promotion happened, false otherwise.
5842bool CodeGenPrepare::tryToPromoteExts(
  TypePromotionTransaction &TPT, const SmallVectorImpl<Instruction *> &Exts,
  SmallVectorImpl<Instruction *> &ProfitablyMovedExts,
  unsigned CreatedInstsCost) {
bool Promoted = false;

// Iterate over all the extensions to try to promote them.
for (auto *I : Exts) {
  // Early check if we directly have ext(load).
  if (isa<LoadInst>(I->getOperand(0))) {
    ProfitablyMovedExts.push_back(I);
    continue;
  }

  // Check whether or not we want to do any promotion.  The reason we have
  // this check inside the for loop is to catch the case where an extension
  // is directly fed by a load because in such case the extension can be moved
  // up without any promotion on its operands.
  if (!TLI->enableExtLdPromotion() || DisableExtLdPromotion)
    return false;

  // Get the action to perform the promotion.
  TypePromotionHelper::Action TPH =
      TypePromotionHelper::getAction(I, InsertedInsts, *TLI, PromotedInsts);
  // Check if we can promote.
  if (!TPH) {
    // Save the current extension as we cannot move up through its operand.
    ProfitablyMovedExts.push_back(I);
    continue;
  }

  // Save the current state.
  TypePromotionTransaction::ConstRestorationPt LastKnownGood =
      TPT.getRestorationPoint();
  SmallVector<Instruction *, 4> NewExts;
  unsigned NewCreatedInstsCost = 0;
  unsigned ExtCost = !TLI->isExtFree(I);
  // Promote.
  Value *PromotedVal = TPH(I, TPT, PromotedInsts, NewCreatedInstsCost,
                           &NewExts, nullptr, *TLI);
  assert(PromotedVal &&(static_cast <bool> (PromotedVal && "TypePromotionHelper should have filtered out those cases"
) ? void (0) : __assert_fail ("PromotedVal && \"TypePromotionHelper should have filtered out those cases\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 5883, __extension__ __PRETTY_FUNCTION__
))
         "TypePromotionHelper should have filtered out those cases")(static_cast <bool> (PromotedVal && "TypePromotionHelper should have filtered out those cases"
) ? void (0) : __assert_fail ("PromotedVal && \"TypePromotionHelper should have filtered out those cases\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 5883, __extension__ __PRETTY_FUNCTION__
));

  // We would be able to merge only one extension in a load.
  // Therefore, if we have more than 1 new extension we heuristically
  // cut this search path, because it means we degrade the code quality.
  // With exactly 2, the transformation is neutral, because we will merge
  // one extension but leave one. However, we optimistically keep going,
  // because the new extension may be removed too.
  long long TotalCreatedInstsCost = CreatedInstsCost + NewCreatedInstsCost;
  // FIXME: It would be possible to propagate a negative value instead of
  // conservatively ceiling it to 0.
  TotalCreatedInstsCost =
      std::max((long long)0, (TotalCreatedInstsCost - ExtCost));
  if (!StressExtLdPromotion &&
      (TotalCreatedInstsCost > 1 ||
       !isPromotedInstructionLegal(*TLI, *DL, PromotedVal))) {
    // This promotion is not profitable, rollback to the previous state, and
    // save the current extension in ProfitablyMovedExts as the latest
    // speculative promotion turned out to be unprofitable.
    TPT.rollback(LastKnownGood);
    ProfitablyMovedExts.push_back(I);
    continue;
  }
  // Continue promoting NewExts as far as doing so is profitable.
  SmallVector<Instruction *, 2> NewlyMovedExts;
  (void)tryToPromoteExts(TPT, NewExts, NewlyMovedExts, TotalCreatedInstsCost);
  bool NewPromoted = false;
  for (auto *ExtInst : NewlyMovedExts) {
    Instruction *MovedExt = cast<Instruction>(ExtInst);
    Value *ExtOperand = MovedExt->getOperand(0);
    // If we have reached to a load, we need this extra profitability check
    // as it could potentially be merged into an ext(load).
    if (isa<LoadInst>(ExtOperand) &&
        !(StressExtLdPromotion || NewCreatedInstsCost <= ExtCost ||
          (ExtOperand->hasOneUse() || hasSameExtUse(ExtOperand, *TLI))))
      continue;

    ProfitablyMovedExts.push_back(MovedExt);
    NewPromoted = true;
  }

  // If none of speculative promotions for NewExts is profitable, rollback
  // and save the current extension (I) as the last profitable extension.
  if (!NewPromoted) {
    TPT.rollback(LastKnownGood);
    ProfitablyMovedExts.push_back(I);
    continue;
  }
  // The promotion is profitable.
  Promoted = true;
}
return Promoted;
5935}

5937/// Merging redundant sexts when one is dominating the other.
5938bool CodeGenPrepare::mergeSExts(Function &F) {
bool Changed = false;
for (auto &Entry : ValToSExtendedUses) {
  SExts &Insts = Entry.second;
  SExts CurPts;
  for (Instruction *Inst : Insts) {
    if (RemovedInsts.count(Inst) || !isa<SExtInst>(Inst) ||
        Inst->getOperand(0) != Entry.first)
      continue;
    bool inserted = false;
    for (auto &Pt : CurPts) {
      if (getDT(F).dominates(Inst, Pt)) {
        replaceAllUsesWith(Pt, Inst, FreshBBs, IsHugeFunc);
        RemovedInsts.insert(Pt);
        Pt->removeFromParent();
        Pt = Inst;
        inserted = true;
        Changed = true;
        break;
      }
      if (!getDT(F).dominates(Pt, Inst))
        // Give up if we need to merge in a common dominator as the
        // experiments show it is not profitable.
        continue;
      replaceAllUsesWith(Inst, Pt, FreshBBs, IsHugeFunc);
      RemovedInsts.insert(Inst);
      Inst->removeFromParent();
      inserted = true;
      Changed = true;
      break;
    }
    if (!inserted)
      CurPts.push_back(Inst);
  }
}
return Changed;
5974}

5976// Splitting large data structures so that the GEPs accessing them can have
5977// smaller offsets so that they can be sunk to the same blocks as their users.
5978// For example, a large struct starting from %base is split into two parts
5979// where the second part starts from %new_base.
5980//
5981// Before:
5982// BB0:
5983//   %base     =
5984//
5985// BB1:
5986//   %gep0     = gep %base, off0
5987//   %gep1     = gep %base, off1
5988//   %gep2     = gep %base, off2
5989//
5990// BB2:
5991//   %load1    = load %gep0
5992//   %load2    = load %gep1
5993//   %load3    = load %gep2
5994//
5995// After:
5996// BB0:
5997//   %base     =
5998//   %new_base = gep %base, off0
5999//
6000// BB1:
6001//   %new_gep0 = %new_base
6002//   %new_gep1 = gep %new_base, off1 - off0
6003//   %new_gep2 = gep %new_base, off2 - off0
6004//
6005// BB2:
6006//   %load1    = load i32, i32* %new_gep0
6007//   %load2    = load i32, i32* %new_gep1
6008//   %load3    = load i32, i32* %new_gep2
6009//
6010// %new_gep1 and %new_gep2 can be sunk to BB2 now after the splitting because
6011// their offsets are smaller enough to fit into the addressing mode.
6012bool CodeGenPrepare::splitLargeGEPOffsets() {
bool Changed = false;
for (auto &Entry : LargeOffsetGEPMap) {
  Value *OldBase = Entry.first;
  SmallVectorImpl<std::pair<AssertingVH<GetElementPtrInst>, int64_t>>
      &LargeOffsetGEPs = Entry.second;
  auto compareGEPOffset =
      [&](const std::pair<GetElementPtrInst *, int64_t> &LHS,
          const std::pair<GetElementPtrInst *, int64_t> &RHS) {
        if (LHS.first == RHS.first)
          return false;
        if (LHS.second != RHS.second)
          return LHS.second < RHS.second;
        return LargeOffsetGEPID[LHS.first] < LargeOffsetGEPID[RHS.first];
      };
  // Sorting all the GEPs of the same data structures based on the offsets.
  llvm::sort(LargeOffsetGEPs, compareGEPOffset);
  LargeOffsetGEPs.erase(
      std::unique(LargeOffsetGEPs.begin(), LargeOffsetGEPs.end()),
      LargeOffsetGEPs.end());
  // Skip if all the GEPs have the same offsets.
  if (LargeOffsetGEPs.front().second == LargeOffsetGEPs.back().second)
    continue;
  GetElementPtrInst *BaseGEP = LargeOffsetGEPs.begin()->first;
  int64_t BaseOffset = LargeOffsetGEPs.begin()->second;
  Value *NewBaseGEP = nullptr;

  auto *LargeOffsetGEP = LargeOffsetGEPs.begin();
  while (LargeOffsetGEP != LargeOffsetGEPs.end()) {
    GetElementPtrInst *GEP = LargeOffsetGEP->first;
    int64_t Offset = LargeOffsetGEP->second;
    if (Offset != BaseOffset) {
      TargetLowering::AddrMode AddrMode;
      AddrMode.HasBaseReg = true;
      AddrMode.BaseOffs = Offset - BaseOffset;
      // The result type of the GEP might not be the type of the memory
      // access.
      if (!TLI->isLegalAddressingMode(*DL, AddrMode,
                                      GEP->getResultElementType(),
                                      GEP->getAddressSpace())) {
        // We need to create a new base if the offset to the current base is
        // too large to fit into the addressing mode. So, a very large struct
        // may be split into several parts.
        BaseGEP = GEP;
        BaseOffset = Offset;
        NewBaseGEP = nullptr;
      }
    }

    // Generate a new GEP to replace the current one.
    LLVMContext &Ctx = GEP->getContext();
    Type *IntPtrTy = DL->getIntPtrType(GEP->getType());
    Type *I8PtrTy =
        Type::getInt8PtrTy(Ctx, GEP->getType()->getPointerAddressSpace());
    Type *I8Ty = Type::getInt8Ty(Ctx);

    if (!NewBaseGEP) {
      // Create a new base if we don't have one yet.  Find the insertion
      // pointer for the new base first.
      BasicBlock::iterator NewBaseInsertPt;
      BasicBlock *NewBaseInsertBB;
      if (auto *BaseI = dyn_cast<Instruction>(OldBase)) {
        // If the base of the struct is an instruction, the new base will be
        // inserted close to it.
        NewBaseInsertBB = BaseI->getParent();
        if (isa<PHINode>(BaseI))
          NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt();
        else if (InvokeInst *Invoke = dyn_cast<InvokeInst>(BaseI)) {
          NewBaseInsertBB =
              SplitEdge(NewBaseInsertBB, Invoke->getNormalDest());
          NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt();
        } else
          NewBaseInsertPt = std::next(BaseI->getIterator());
      } else {
        // If the current base is an argument or global value, the new base
        // will be inserted to the entry block.
        NewBaseInsertBB = &BaseGEP->getFunction()->getEntryBlock();
        NewBaseInsertPt = NewBaseInsertBB->getFirstInsertionPt();
      }
      IRBuilder<> NewBaseBuilder(NewBaseInsertBB, NewBaseInsertPt);
      // Create a new base.
      Value *BaseIndex = ConstantInt::get(IntPtrTy, BaseOffset);
      NewBaseGEP = OldBase;
      if (NewBaseGEP->getType() != I8PtrTy)
        NewBaseGEP = NewBaseBuilder.CreatePointerCast(NewBaseGEP, I8PtrTy);
      NewBaseGEP =
          NewBaseBuilder.CreateGEP(I8Ty, NewBaseGEP, BaseIndex, "splitgep");
      NewGEPBases.insert(NewBaseGEP);
    }

    IRBuilder<> Builder(GEP);
    Value *NewGEP = NewBaseGEP;
    if (Offset == BaseOffset) {
      if (GEP->getType() != I8PtrTy)
        NewGEP = Builder.CreatePointerCast(NewGEP, GEP->getType());
    } else {
      // Calculate the new offset for the new GEP.
      Value *Index = ConstantInt::get(IntPtrTy, Offset - BaseOffset);
      NewGEP = Builder.CreateGEP(I8Ty, NewBaseGEP, Index);

      if (GEP->getType() != I8PtrTy)
        NewGEP = Builder.CreatePointerCast(NewGEP, GEP->getType());
    }
    replaceAllUsesWith(GEP, NewGEP, FreshBBs, IsHugeFunc);
    LargeOffsetGEPID.erase(GEP);
    LargeOffsetGEP = LargeOffsetGEPs.erase(LargeOffsetGEP);
    GEP->eraseFromParent();
    Changed = true;
  }
}
return Changed;
6123}

6125bool CodeGenPrepare::optimizePhiType(
  PHINode *I, SmallPtrSetImpl<PHINode *> &Visited,
  SmallPtrSetImpl<Instruction *> &DeletedInstrs) {
// We are looking for a collection on interconnected phi nodes that together
// only use loads/bitcasts and are used by stores/bitcasts, and the bitcasts
// are of the same type. Convert the whole set of nodes to the type of the
// bitcast.
Type *PhiTy = I->getType();
Type *ConvertTy = nullptr;
if (Visited.count(I) ||
    (!I->getType()->isIntegerTy() && !I->getType()->isFloatingPointTy()))
  return false;

SmallVector<Instruction *, 4> Worklist;
Worklist.push_back(cast<Instruction>(I));
SmallPtrSet<PHINode *, 4> PhiNodes;
SmallPtrSet<ConstantData *, 4> Constants;
PhiNodes.insert(I);
Visited.insert(I);
SmallPtrSet<Instruction *, 4> Defs;
SmallPtrSet<Instruction *, 4> Uses;
// This works by adding extra bitcasts between load/stores and removing
// existing bicasts. If we have a phi(bitcast(load)) or a store(bitcast(phi))
// we can get in the situation where we remove a bitcast in one iteration
// just to add it again in the next. We need to ensure that at least one
// bitcast we remove are anchored to something that will not change back.
bool AnyAnchored = false;

while (!Worklist.empty()) {
  Instruction *II = Worklist.pop_back_val();

  if (auto *Phi = dyn_cast<PHINode>(II)) {
    // Handle Defs, which might also be PHI's
    for (Value *V : Phi->incoming_values()) {
      if (auto *OpPhi = dyn_cast<PHINode>(V)) {
        if (!PhiNodes.count(OpPhi)) {
          if (!Visited.insert(OpPhi).second)
            return false;
          PhiNodes.insert(OpPhi);
          Worklist.push_back(OpPhi);
        }
      } else if (auto *OpLoad = dyn_cast<LoadInst>(V)) {
        if (!OpLoad->isSimple())
          return false;
        if (Defs.insert(OpLoad).second)
          Worklist.push_back(OpLoad);
      } else if (auto *OpEx = dyn_cast<ExtractElementInst>(V)) {
        if (Defs.insert(OpEx).second)
          Worklist.push_back(OpEx);
      } else if (auto *OpBC = dyn_cast<BitCastInst>(V)) {
        if (!ConvertTy)
          ConvertTy = OpBC->getOperand(0)->getType();
        if (OpBC->getOperand(0)->getType() != ConvertTy)
          return false;
        if (Defs.insert(OpBC).second) {
          Worklist.push_back(OpBC);
          AnyAnchored |= !isa<LoadInst>(OpBC->getOperand(0)) &&
                         !isa<ExtractElementInst>(OpBC->getOperand(0));
        }
      } else if (auto *OpC = dyn_cast<ConstantData>(V))
        Constants.insert(OpC);
      else
        return false;
    }
  }

  // Handle uses which might also be phi's
  for (User *V : II->users()) {
    if (auto *OpPhi = dyn_cast<PHINode>(V)) {
      if (!PhiNodes.count(OpPhi)) {
        if (Visited.count(OpPhi))
          return false;
        PhiNodes.insert(OpPhi);
        Visited.insert(OpPhi);
        Worklist.push_back(OpPhi);
      }
    } else if (auto *OpStore = dyn_cast<StoreInst>(V)) {
      if (!OpStore->isSimple() || OpStore->getOperand(0) != II)
        return false;
      Uses.insert(OpStore);
    } else if (auto *OpBC = dyn_cast<BitCastInst>(V)) {
      if (!ConvertTy)
        ConvertTy = OpBC->getType();
      if (OpBC->getType() != ConvertTy)
        return false;
      Uses.insert(OpBC);
      AnyAnchored |=
          any_of(OpBC->users(), [](User *U) { return !isa<StoreInst>(U); });
    } else {
      return false;
    }
  }
}

if (!ConvertTy || !AnyAnchored ||
    !TLI->shouldConvertPhiType(PhiTy, ConvertTy))
  return false;

LLVM_DEBUG(dbgs() << "Converting " << *I << "\n  and connected nodes to "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Converting " << *
I << "\n  and connected nodes to " << *ConvertTy <<
 "\n"; } } while (false)
                  << *ConvertTy << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Converting " << *
I << "\n  and connected nodes to " << *ConvertTy <<
 "\n"; } } while (false);

// Create all the new phi nodes of the new type, and bitcast any loads to the
// correct type.
ValueToValueMap ValMap;
for (ConstantData *C : Constants)
  ValMap[C] = ConstantExpr::getCast(Instruction::BitCast, C, ConvertTy);
for (Instruction *D : Defs) {
  if (isa<BitCastInst>(D)) {
    ValMap[D] = D->getOperand(0);
    DeletedInstrs.insert(D);
  } else {
    ValMap[D] =
        new BitCastInst(D, ConvertTy, D->getName() + ".bc", D->getNextNode());
  }
}
for (PHINode *Phi : PhiNodes)
  ValMap[Phi] = PHINode::Create(ConvertTy, Phi->getNumIncomingValues(),
                                Phi->getName() + ".tc", Phi);
// Pipe together all the PhiNodes.
for (PHINode *Phi : PhiNodes) {
  PHINode *NewPhi = cast<PHINode>(ValMap[Phi]);
  for (int i = 0, e = Phi->getNumIncomingValues(); i < e; i++)
    NewPhi->addIncoming(ValMap[Phi->getIncomingValue(i)],
                        Phi->getIncomingBlock(i));
  Visited.insert(NewPhi);
}
// And finally pipe up the stores and bitcasts
for (Instruction *U : Uses) {
  if (isa<BitCastInst>(U)) {
    DeletedInstrs.insert(U);
    replaceAllUsesWith(U, ValMap[U->getOperand(0)], FreshBBs, IsHugeFunc);
  } else {
    U->setOperand(0,
                  new BitCastInst(ValMap[U->getOperand(0)], PhiTy, "bc", U));
  }
}

// Save the removed phis to be deleted later.
for (PHINode *Phi : PhiNodes)
  DeletedInstrs.insert(Phi);
return true;
6266}

6268bool CodeGenPrepare::optimizePhiTypes(Function &F) {
if (!OptimizePhiTypes)
  return false;

bool Changed = false;
SmallPtrSet<PHINode *, 4> Visited;
SmallPtrSet<Instruction *, 4> DeletedInstrs;

// Attempt to optimize all the phis in the functions to the correct type.
for (auto &BB : F)
  for (auto &Phi : BB.phis())
    Changed |= optimizePhiType(&Phi, Visited, DeletedInstrs);

// Remove any old phi's that have been converted.
for (auto *I : DeletedInstrs) {
  replaceAllUsesWith(I, PoisonValue::get(I->getType()), FreshBBs, IsHugeFunc);
  I->eraseFromParent();
}

return Changed;
6288}

6290/// Return true, if an ext(load) can be formed from an extension in
6291/// \p MovedExts.
6292bool CodeGenPrepare::canFormExtLd(
  const SmallVectorImpl<Instruction *> &MovedExts, LoadInst *&LI,
  Instruction *&Inst, bool HasPromoted) {
for (auto *MovedExtInst : MovedExts) {
  if (isa<LoadInst>(MovedExtInst->getOperand(0))) {
    LI = cast<LoadInst>(MovedExtInst->getOperand(0));
    Inst = MovedExtInst;
    break;
  }
}
if (!LI)
  return false;

// If they're already in the same block, there's nothing to do.
// Make the cheap checks first if we did not promote.
// If we promoted, we need to check if it is indeed profitable.
if (!HasPromoted && LI->getParent() == Inst->getParent())
  return false;

return TLI->isExtLoad(LI, Inst, *DL);
6312}

6314/// Move a zext or sext fed by a load into the same basic block as the load,
6315/// unless conditions are unfavorable. This allows SelectionDAG to fold the
6316/// extend into the load.
6317///
6318/// E.g.,
6319/// \code
6320/// %ld = load i32* %addr
6321/// %add = add nuw i32 %ld, 4
6322/// %zext = zext i32 %add to i64
6323// \endcode
6324/// =>
6325/// \code
6326/// %ld = load i32* %addr
6327/// %zext = zext i32 %ld to i64
6328/// %add = add nuw i64 %zext, 4
6329/// \encode
6330/// Note that the promotion in %add to i64 is done in tryToPromoteExts(), which
6331/// allow us to match zext(load i32*) to i64.
6332///
6333/// Also, try to promote the computations used to obtain a sign extended
6334/// value used into memory accesses.
6335/// E.g.,
6336/// \code
6337/// a = add nsw i32 b, 3
6338/// d = sext i32 a to i64
6339/// e = getelementptr ..., i64 d
6340/// \endcode
6341/// =>
6342/// \code
6343/// f = sext i32 b to i64
6344/// a = add nsw i64 f, 3
6345/// e = getelementptr ..., i64 a
6346/// \endcode
6347///
6348/// \p Inst[in/out] the extension may be modified during the process if some
6349/// promotions apply.
6350bool CodeGenPrepare::optimizeExt(Instruction *&Inst) {
bool AllowPromotionWithoutCommonHeader = false;
/// See if it is an interesting sext operations for the address type
/// promotion before trying to promote it, e.g., the ones with the right
/// type and used in memory accesses.
bool ATPConsiderable = TTI->shouldConsiderAddressTypePromotion(
    *Inst, AllowPromotionWithoutCommonHeader);
TypePromotionTransaction TPT(RemovedInsts);
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
    TPT.getRestorationPoint();
SmallVector<Instruction *, 1> Exts;
SmallVector<Instruction *, 2> SpeculativelyMovedExts;
Exts.push_back(Inst);

bool HasPromoted = tryToPromoteExts(TPT, Exts, SpeculativelyMovedExts);

// Look for a load being extended.
LoadInst *LI = nullptr;
Instruction *ExtFedByLoad;

// Try to promote a chain of computation if it allows to form an extended
// load.
if (canFormExtLd(SpeculativelyMovedExts, LI, ExtFedByLoad, HasPromoted)) {
  assert(LI && ExtFedByLoad && "Expect a valid load and extension")(static_cast <bool> (LI && ExtFedByLoad &&
 "Expect a valid load and extension") ? void (0) : __assert_fail
 ("LI && ExtFedByLoad && \"Expect a valid load and extension\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 6373, __extension__ __PRETTY_FUNCTION__
));
  TPT.commit();
  // Move the extend into the same block as the load.
  ExtFedByLoad->moveAfter(LI);
  ++NumExtsMoved;
  Inst = ExtFedByLoad;
  return true;
}

// Continue promoting SExts if known as considerable depending on targets.
if (ATPConsiderable &&
    performAddressTypePromotion(Inst, AllowPromotionWithoutCommonHeader,
                                HasPromoted, TPT, SpeculativelyMovedExts))
  return true;

TPT.rollback(LastKnownGood);
return false;
6390}

6392// Perform address type promotion if doing so is profitable.
6393// If AllowPromotionWithoutCommonHeader == false, we should find other sext
6394// instructions that sign extended the same initial value. However, if
6395// AllowPromotionWithoutCommonHeader == true, we expect promoting the
6396// extension is just profitable.
6397bool CodeGenPrepare::performAddressTypePromotion(
  Instruction *&Inst, bool AllowPromotionWithoutCommonHeader,
  bool HasPromoted, TypePromotionTransaction &TPT,
  SmallVectorImpl<Instruction *> &SpeculativelyMovedExts) {
bool Promoted = false;
SmallPtrSet<Instruction *, 1> UnhandledExts;
bool AllSeenFirst = true;
for (auto *I : SpeculativelyMovedExts) {
  Value *HeadOfChain = I->getOperand(0);
  DenseMap<Value *, Instruction *>::iterator AlreadySeen =
      SeenChainsForSExt.find(HeadOfChain);
  // If there is an unhandled SExt which has the same header, try to promote
  // it as well.
  if (AlreadySeen != SeenChainsForSExt.end()) {
    if (AlreadySeen->second != nullptr)
      UnhandledExts.insert(AlreadySeen->second);
    AllSeenFirst = false;
  }
}

if (!AllSeenFirst || (AllowPromotionWithoutCommonHeader &&
                      SpeculativelyMovedExts.size() == 1)) {
  TPT.commit();
  if (HasPromoted)
    Promoted = true;
  for (auto *I : SpeculativelyMovedExts) {
    Value *HeadOfChain = I->getOperand(0);
    SeenChainsForSExt[HeadOfChain] = nullptr;
    ValToSExtendedUses[HeadOfChain].push_back(I);
  }
  // Update Inst as promotion happen.
  Inst = SpeculativelyMovedExts.pop_back_val();
} else {
  // This is the first chain visited from the header, keep the current chain
  // as unhandled. Defer to promote this until we encounter another SExt
  // chain derived from the same header.
  for (auto *I : SpeculativelyMovedExts) {
    Value *HeadOfChain = I->getOperand(0);
    SeenChainsForSExt[HeadOfChain] = Inst;
  }
  return false;
}

if (!AllSeenFirst && !UnhandledExts.empty())
  for (auto *VisitedSExt : UnhandledExts) {
    if (RemovedInsts.count(VisitedSExt))
      continue;
    TypePromotionTransaction TPT(RemovedInsts);
    SmallVector<Instruction *, 1> Exts;
    SmallVector<Instruction *, 2> Chains;
    Exts.push_back(VisitedSExt);
    bool HasPromoted = tryToPromoteExts(TPT, Exts, Chains);
    TPT.commit();
    if (HasPromoted)
      Promoted = true;
    for (auto *I : Chains) {
      Value *HeadOfChain = I->getOperand(0);
      // Mark this as handled.
      SeenChainsForSExt[HeadOfChain] = nullptr;
      ValToSExtendedUses[HeadOfChain].push_back(I);
    }
  }
return Promoted;
6460}

6462bool CodeGenPrepare::optimizeExtUses(Instruction *I) {
BasicBlock *DefBB = I->getParent();

// If the result of a {s|z}ext and its source are both live out, rewrite all
// other uses of the source with result of extension.
Value *Src = I->getOperand(0);
if (Src->hasOneUse())
  return false;

// Only do this xform if truncating is free.
if (!TLI->isTruncateFree(I->getType(), Src->getType()))
  return false;

// Only safe to perform the optimization if the source is also defined in
// this block.
if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent())
  return false;

bool DefIsLiveOut = false;
for (User *U : I->users()) {
  Instruction *UI = cast<Instruction>(U);

  // Figure out which BB this ext is used in.
  BasicBlock *UserBB = UI->getParent();
  if (UserBB == DefBB)
    continue;
  DefIsLiveOut = true;
  break;
}
if (!DefIsLiveOut)
  return false;

// Make sure none of the uses are PHI nodes.
for (User *U : Src->users()) {
  Instruction *UI = cast<Instruction>(U);
  BasicBlock *UserBB = UI->getParent();
  if (UserBB == DefBB)
    continue;
  // Be conservative. We don't want this xform to end up introducing
  // reloads just before load / store instructions.
  if (isa<PHINode>(UI) || isa<LoadInst>(UI) || isa<StoreInst>(UI))
    return false;
}

// InsertedTruncs - Only insert one trunc in each block once.
DenseMap<BasicBlock *, Instruction *> InsertedTruncs;

bool MadeChange = false;
for (Use &U : Src->uses()) {
  Instruction *User = cast<Instruction>(U.getUser());

  // Figure out which BB this ext is used in.
  BasicBlock *UserBB = User->getParent();
  if (UserBB == DefBB)
    continue;

  // Both src and def are live in this block. Rewrite the use.
  Instruction *&InsertedTrunc = InsertedTruncs[UserBB];

  if (!InsertedTrunc) {
    BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
    assert(InsertPt != UserBB->end())(static_cast <bool> (InsertPt != UserBB->end()) ? void
 (0) : __assert_fail ("InsertPt != UserBB->end()", "llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 6523, __extension__ __PRETTY_FUNCTION__));
    InsertedTrunc = new TruncInst(I, Src->getType(), "", &*InsertPt);
    InsertedInsts.insert(InsertedTrunc);
  }

  // Replace a use of the {s|z}ext source with a use of the result.
  U = InsertedTrunc;
  ++NumExtUses;
  MadeChange = true;
}

return MadeChange;
6535}

6537// Find loads whose uses only use some of the loaded value's bits.  Add an "and"
6538// just after the load if the target can fold this into one extload instruction,
6539// with the hope of eliminating some of the other later "and" instructions using
6540// the loaded value.  "and"s that are made trivially redundant by the insertion
6541// of the new "and" are removed by this function, while others (e.g. those whose
6542// path from the load goes through a phi) are left for isel to potentially
6543// remove.
6544//
6545// For example:
6546//
6547// b0:
6548//   x = load i32
6549//   ...
6550// b1:
6551//   y = and x, 0xff
6552//   z = use y
6553//
6554// becomes:
6555//
6556// b0:
6557//   x = load i32
6558//   x' = and x, 0xff
6559//   ...
6560// b1:
6561//   z = use x'
6562//
6563// whereas:
6564//
6565// b0:
6566//   x1 = load i32
6567//   ...
6568// b1:
6569//   x2 = load i32
6570//   ...
6571// b2:
6572//   x = phi x1, x2
6573//   y = and x, 0xff
6574//
6575// becomes (after a call to optimizeLoadExt for each load):
6576//
6577// b0:
6578//   x1 = load i32
6579//   x1' = and x1, 0xff
6580//   ...
6581// b1:
6582//   x2 = load i32
6583//   x2' = and x2, 0xff
6584//   ...
6585// b2:
6586//   x = phi x1', x2'
6587//   y = and x, 0xff
6588bool CodeGenPrepare::optimizeLoadExt(LoadInst *Load) {
if (!Load->isSimple() || !Load->getType()->isIntOrPtrTy())
  return false;

// Skip loads we've already transformed.
if (Load->hasOneUse() &&
    InsertedInsts.count(cast<Instruction>(*Load->user_begin())))
  return false;

// Look at all uses of Load, looking through phis, to determine how many bits
// of the loaded value are needed.
SmallVector<Instruction *, 8> WorkList;
SmallPtrSet<Instruction *, 16> Visited;
SmallVector<Instruction *, 8> AndsToMaybeRemove;
for (auto *U : Load->users())
  WorkList.push_back(cast<Instruction>(U));

EVT LoadResultVT = TLI->getValueType(*DL, Load->getType());
unsigned BitWidth = LoadResultVT.getSizeInBits();
// If the BitWidth is 0, do not try to optimize the type
if (BitWidth == 0)
  return false;

APInt DemandBits(BitWidth, 0);
APInt WidestAndBits(BitWidth, 0);

while (!WorkList.empty()) {
  Instruction *I = WorkList.pop_back_val();

  // Break use-def graph loops.
  if (!Visited.insert(I).second)
    continue;

  // For a PHI node, push all of its users.
  if (auto *Phi = dyn_cast<PHINode>(I)) {
    for (auto *U : Phi->users())
      WorkList.push_back(cast<Instruction>(U));
    continue;
  }

  switch (I->getOpcode()) {
  case Instruction::And: {
    auto *AndC = dyn_cast<ConstantInt>(I->getOperand(1));
    if (!AndC)
      return false;
    APInt AndBits = AndC->getValue();
    DemandBits |= AndBits;
    // Keep track of the widest and mask we see.
    if (AndBits.ugt(WidestAndBits))
      WidestAndBits = AndBits;
    if (AndBits == WidestAndBits && I->getOperand(0) == Load)
      AndsToMaybeRemove.push_back(I);
    break;
  }

  case Instruction::Shl: {
    auto *ShlC = dyn_cast<ConstantInt>(I->getOperand(1));
    if (!ShlC)
      return false;
    uint64_t ShiftAmt = ShlC->getLimitedValue(BitWidth - 1);
    DemandBits.setLowBits(BitWidth - ShiftAmt);
    break;
  }

  case Instruction::Trunc: {
    EVT TruncVT = TLI->getValueType(*DL, I->getType());
    unsigned TruncBitWidth = TruncVT.getSizeInBits();
    DemandBits.setLowBits(TruncBitWidth);
    break;
  }

  default:
    return false;
  }
}

uint32_t ActiveBits = DemandBits.getActiveBits();
// Avoid hoisting (and (load x) 1) since it is unlikely to be folded by the
// target even if isLoadExtLegal says an i1 EXTLOAD is valid.  For example,
// for the AArch64 target isLoadExtLegal(ZEXTLOAD, i32, i1) returns true, but
// (and (load x) 1) is not matched as a single instruction, rather as a LDR
// followed by an AND.
// TODO: Look into removing this restriction by fixing backends to either
// return false for isLoadExtLegal for i1 or have them select this pattern to
// a single instruction.
//
// Also avoid hoisting if we didn't see any ands with the exact DemandBits
// mask, since these are the only ands that will be removed by isel.
if (ActiveBits <= 1 || !DemandBits.isMask(ActiveBits) ||
    WidestAndBits != DemandBits)
  return false;

LLVMContext &Ctx = Load->getType()->getContext();
Type *TruncTy = Type::getIntNTy(Ctx, ActiveBits);
EVT TruncVT = TLI->getValueType(*DL, TruncTy);

// Reject cases that won't be matched as extloads.
if (!LoadResultVT.bitsGT(TruncVT) || !TruncVT.isRound() ||
    !TLI->isLoadExtLegal(ISD::ZEXTLOAD, LoadResultVT, TruncVT))
  return false;

IRBuilder<> Builder(Load->getNextNode());
auto *NewAnd = cast<Instruction>(
    Builder.CreateAnd(Load, ConstantInt::get(Ctx, DemandBits)));
// Mark this instruction as "inserted by CGP", so that other
// optimizations don't touch it.
InsertedInsts.insert(NewAnd);

// Replace all uses of load with new and (except for the use of load in the
// new and itself).
replaceAllUsesWith(Load, NewAnd, FreshBBs, IsHugeFunc);
NewAnd->setOperand(0, Load);

// Remove any and instructions that are now redundant.
for (auto *And : AndsToMaybeRemove)
  // Check that the and mask is the same as the one we decided to put on the
  // new and.
  if (cast<ConstantInt>(And->getOperand(1))->getValue() == DemandBits) {
    replaceAllUsesWith(And, NewAnd, FreshBBs, IsHugeFunc);
    if (&*CurInstIterator == And)
      CurInstIterator = std::next(And->getIterator());
    And->eraseFromParent();
    ++NumAndUses;
  }

++NumAndsAdded;
return true;
6715}

6717/// Check if V (an operand of a select instruction) is an expensive instruction
6718/// that is only used once.
6719static bool sinkSelectOperand(const TargetTransformInfo *TTI, Value *V) {
auto *I = dyn_cast<Instruction>(V);
// If it's safe to speculatively execute, then it should not have side
// effects; therefore, it's safe to sink and possibly *not* execute.
return I && I->hasOneUse() && isSafeToSpeculativelyExecute(I) &&
       TTI->isExpensiveToSpeculativelyExecute(I);
6725}

6727/// Returns true if a SelectInst should be turned into an explicit branch.
6728static bool isFormingBranchFromSelectProfitable(const TargetTransformInfo *TTI,
                                              const TargetLowering *TLI,
                                              SelectInst *SI) {
// If even a predictable select is cheap, then a branch can't be cheaper.
if (!TLI->isPredictableSelectExpensive())
  return false;

// FIXME: This should use the same heuristics as IfConversion to determine
// whether a select is better represented as a branch.

// If metadata tells us that the select condition is obviously predictable,
// then we want to replace the select with a branch.
uint64_t TrueWeight, FalseWeight;
if (extractBranchWeights(*SI, TrueWeight, FalseWeight)) {
  uint64_t Max = std::max(TrueWeight, FalseWeight);
  uint64_t Sum = TrueWeight + FalseWeight;
  if (Sum != 0) {
    auto Probability = BranchProbability::getBranchProbability(Max, Sum);
    if (Probability > TTI->getPredictableBranchThreshold())
      return true;
  }
}

CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());

// If a branch is predictable, an out-of-order CPU can avoid blocking on its
// comparison condition. If the compare has more than one use, there's
// probably another cmov or setcc around, so it's not worth emitting a branch.
if (!Cmp || !Cmp->hasOneUse())
  return false;

// If either operand of the select is expensive and only needed on one side
// of the select, we should form a branch.
if (sinkSelectOperand(TTI, SI->getTrueValue()) ||
    sinkSelectOperand(TTI, SI->getFalseValue()))
  return true;

return false;
6766}

6768/// If \p isTrue is true, return the true value of \p SI, otherwise return
6769/// false value of \p SI. If the true/false value of \p SI is defined by any
6770/// select instructions in \p Selects, look through the defining select
6771/// instruction until the true/false value is not defined in \p Selects.
6772static Value *
6773getTrueOrFalseValue(SelectInst *SI, bool isTrue,
                  const SmallPtrSet<const Instruction *, 2> &Selects) {
Value *V = nullptr;

for (SelectInst *DefSI = SI; DefSI != nullptr && Selects.count(DefSI);
     DefSI = dyn_cast<SelectInst>(V)) {
  assert(DefSI->getCondition() == SI->getCondition() &&(static_cast <bool> (DefSI->getCondition() == SI->
getCondition() && "The condition of DefSI does not match with SI"
) ? void (0) : __assert_fail ("DefSI->getCondition() == SI->getCondition() && \"The condition of DefSI does not match with SI\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 6780, __extension__ __PRETTY_FUNCTION__
))
         "The condition of DefSI does not match with SI")(static_cast <bool> (DefSI->getCondition() == SI->
getCondition() && "The condition of DefSI does not match with SI"
) ? void (0) : __assert_fail ("DefSI->getCondition() == SI->getCondition() && \"The condition of DefSI does not match with SI\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 6780, __extension__ __PRETTY_FUNCTION__
));
  V = (isTrue ? DefSI->getTrueValue() : DefSI->getFalseValue());
}

assert(V && "Failed to get select true/false value")(static_cast <bool> (V && "Failed to get select true/false value"
) ? void (0) : __assert_fail ("V && \"Failed to get select true/false value\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 6784, __extension__ __PRETTY_FUNCTION__
));
return V;
6786}

6788bool CodeGenPrepare::optimizeShiftInst(BinaryOperator *Shift) {
assert(Shift->isShift() && "Expected a shift")(static_cast <bool> (Shift->isShift() && "Expected a shift"
) ? void (0) : __assert_fail ("Shift->isShift() && \"Expected a shift\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 6789, __extension__ __PRETTY_FUNCTION__
));

// If this is (1) a vector shift, (2) shifts by scalars are cheaper than
// general vector shifts, and (3) the shift amount is a select-of-splatted
// values, hoist the shifts before the select:
//   shift Op0, (select Cond, TVal, FVal) -->
//   select Cond, (shift Op0, TVal), (shift Op0, FVal)
//
// This is inverting a generic IR transform when we know that the cost of a
// general vector shift is more than the cost of 2 shift-by-scalars.
// We can't do this effectively in SDAG because we may not be able to
// determine if the select operands are splats from within a basic block.
Type *Ty = Shift->getType();
if (!Ty->isVectorTy() || !TLI->isVectorShiftByScalarCheap(Ty))
  return false;
Value *Cond, *TVal, *FVal;
if (!match(Shift->getOperand(1),
           m_OneUse(m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))))
  return false;
if (!isSplatValue(TVal) || !isSplatValue(FVal))
  return false;

IRBuilder<> Builder(Shift);
BinaryOperator::BinaryOps Opcode = Shift->getOpcode();
Value *NewTVal = Builder.CreateBinOp(Opcode, Shift->getOperand(0), TVal);
Value *NewFVal = Builder.CreateBinOp(Opcode, Shift->getOperand(0), FVal);
Value *NewSel = Builder.CreateSelect(Cond, NewTVal, NewFVal);
replaceAllUsesWith(Shift, NewSel, FreshBBs, IsHugeFunc);
Shift->eraseFromParent();
return true;
6819}

6821bool CodeGenPrepare::optimizeFunnelShift(IntrinsicInst *Fsh) {
Intrinsic::ID Opcode = Fsh->getIntrinsicID();
assert((Opcode == Intrinsic::fshl || Opcode == Intrinsic::fshr) &&(static_cast <bool> ((Opcode == Intrinsic::fshl || Opcode
 == Intrinsic::fshr) && "Expected a funnel shift") ? void
 (0) : __assert_fail ("(Opcode == Intrinsic::fshl || Opcode == Intrinsic::fshr) && \"Expected a funnel shift\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 6824, __extension__ __PRETTY_FUNCTION__
))
       "Expected a funnel shift")(static_cast <bool> ((Opcode == Intrinsic::fshl || Opcode
 == Intrinsic::fshr) && "Expected a funnel shift") ? void
 (0) : __assert_fail ("(Opcode == Intrinsic::fshl || Opcode == Intrinsic::fshr) && \"Expected a funnel shift\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 6824, __extension__ __PRETTY_FUNCTION__
));

// If this is (1) a vector funnel shift, (2) shifts by scalars are cheaper
// than general vector shifts, and (3) the shift amount is select-of-splatted
// values, hoist the funnel shifts before the select:
//   fsh Op0, Op1, (select Cond, TVal, FVal) -->
//   select Cond, (fsh Op0, Op1, TVal), (fsh Op0, Op1, FVal)
//
// This is inverting a generic IR transform when we know that the cost of a
// general vector shift is more than the cost of 2 shift-by-scalars.
// We can't do this effectively in SDAG because we may not be able to
// determine if the select operands are splats from within a basic block.
Type *Ty = Fsh->getType();
if (!Ty->isVectorTy() || !TLI->isVectorShiftByScalarCheap(Ty))
  return false;
Value *Cond, *TVal, *FVal;
if (!match(Fsh->getOperand(2),
           m_OneUse(m_Select(m_Value(Cond), m_Value(TVal), m_Value(FVal)))))
  return false;
if (!isSplatValue(TVal) || !isSplatValue(FVal))
  return false;

IRBuilder<> Builder(Fsh);
Value *X = Fsh->getOperand(0), *Y = Fsh->getOperand(1);
Value *NewTVal = Builder.CreateIntrinsic(Opcode, Ty, {X, Y, TVal});
Value *NewFVal = Builder.CreateIntrinsic(Opcode, Ty, {X, Y, FVal});
Value *NewSel = Builder.CreateSelect(Cond, NewTVal, NewFVal);
replaceAllUsesWith(Fsh, NewSel, FreshBBs, IsHugeFunc);
Fsh->eraseFromParent();
return true;
6854}

6856/// If we have a SelectInst that will likely profit from branch prediction,
6857/// turn it into a branch.
6858bool CodeGenPrepare::optimizeSelectInst(SelectInst *SI) {
if (DisableSelectToBranch)
  return false;

// If the SelectOptimize pass is enabled, selects have already been optimized.
if (!getCGPassBuilderOption().DisableSelectOptimize)
  return false;

// Find all consecutive select instructions that share the same condition.
SmallVector<SelectInst *, 2> ASI;
ASI.push_back(SI);
for (BasicBlock::iterator It = ++BasicBlock::iterator(SI);
     It != SI->getParent()->end(); ++It) {
  SelectInst *I = dyn_cast<SelectInst>(&*It);
  if (I && SI->getCondition() == I->getCondition()) {
    ASI.push_back(I);
  } else {
    break;
  }
}

SelectInst *LastSI = ASI.back();
// Increment the current iterator to skip all the rest of select instructions
// because they will be either "not lowered" or "all lowered" to branch.
CurInstIterator = std::next(LastSI->getIterator());

bool VectorCond = !SI->getCondition()->getType()->isIntegerTy(1);

// Can we convert the 'select' to CF ?
if (VectorCond || SI->getMetadata(LLVMContext::MD_unpredictable))
  return false;

TargetLowering::SelectSupportKind SelectKind;
if (SI->getType()->isVectorTy())
  SelectKind = TargetLowering::ScalarCondVectorVal;
else
  SelectKind = TargetLowering::ScalarValSelect;

if (TLI->isSelectSupported(SelectKind) &&
    (!isFormingBranchFromSelectProfitable(TTI, TLI, SI) || OptSize ||
     llvm::shouldOptimizeForSize(SI->getParent(), PSI, BFI.get())))
  return false;

// The DominatorTree needs to be rebuilt by any consumers after this
// transformation. We simply reset here rather than setting the ModifiedDT
// flag to avoid restarting the function walk in runOnFunction for each
// select optimized.
DT.reset();

// Transform a sequence like this:
//    start:
//       %cmp = cmp uge i32 %a, %b
//       %sel = select i1 %cmp, i32 %c, i32 %d
//
// Into:
//    start:
//       %cmp = cmp uge i32 %a, %b
//       %cmp.frozen = freeze %cmp
//       br i1 %cmp.frozen, label %select.true, label %select.false
//    select.true:
//       br label %select.end
//    select.false:
//       br label %select.end
//    select.end:
//       %sel = phi i32 [ %c, %select.true ], [ %d, %select.false ]
//
// %cmp should be frozen, otherwise it may introduce undefined behavior.
// In addition, we may sink instructions that produce %c or %d from
// the entry block into the destination(s) of the new branch.
// If the true or false blocks do not contain a sunken instruction, that
// block and its branch may be optimized away. In that case, one side of the
// first branch will point directly to select.end, and the corresponding PHI
// predecessor block will be the start block.

// First, we split the block containing the select into 2 blocks.
BasicBlock *StartBlock = SI->getParent();
BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(LastSI));
BasicBlock *EndBlock = StartBlock->splitBasicBlock(SplitPt, "select.end");
if (IsHugeFunc)
  FreshBBs.insert(EndBlock);
BFI->setBlockFreq(EndBlock, BFI->getBlockFreq(StartBlock).getFrequency());

// Delete the unconditional branch that was just created by the split.
StartBlock->getTerminator()->eraseFromParent();

// These are the new basic blocks for the conditional branch.
// At least one will become an actual new basic block.
BasicBlock *TrueBlock = nullptr;
BasicBlock *FalseBlock = nullptr;
BranchInst *TrueBranch = nullptr;
BranchInst *FalseBranch = nullptr;

// Sink expensive instructions into the conditional blocks to avoid executing
// them speculatively.
for (SelectInst *SI : ASI) {
  if (sinkSelectOperand(TTI, SI->getTrueValue())) {
    if (TrueBlock == nullptr) {
      TrueBlock = BasicBlock::Create(SI->getContext(), "select.true.sink",
                                     EndBlock->getParent(), EndBlock);
      TrueBranch = BranchInst::Create(EndBlock, TrueBlock);
      if (IsHugeFunc)
        FreshBBs.insert(TrueBlock);
      TrueBranch->setDebugLoc(SI->getDebugLoc());
    }
    auto *TrueInst = cast<Instruction>(SI->getTrueValue());
    TrueInst->moveBefore(TrueBranch);
  }
  if (sinkSelectOperand(TTI, SI->getFalseValue())) {
    if (FalseBlock == nullptr) {
      FalseBlock = BasicBlock::Create(SI->getContext(), "select.false.sink",
                                      EndBlock->getParent(), EndBlock);
      if (IsHugeFunc)
        FreshBBs.insert(FalseBlock);
      FalseBranch = BranchInst::Create(EndBlock, FalseBlock);
      FalseBranch->setDebugLoc(SI->getDebugLoc());
    }
    auto *FalseInst = cast<Instruction>(SI->getFalseValue());
    FalseInst->moveBefore(FalseBranch);
  }
}

// If there was nothing to sink, then arbitrarily choose the 'false' side
// for a new input value to the PHI.
if (TrueBlock == FalseBlock) {
  assert(TrueBlock == nullptr &&(static_cast <bool> (TrueBlock == nullptr && "Unexpected basic block transform while optimizing select"
) ? void (0) : __assert_fail ("TrueBlock == nullptr && \"Unexpected basic block transform while optimizing select\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 6983, __extension__ __PRETTY_FUNCTION__
))
         "Unexpected basic block transform while optimizing select")(static_cast <bool> (TrueBlock == nullptr && "Unexpected basic block transform while optimizing select"
) ? void (0) : __assert_fail ("TrueBlock == nullptr && \"Unexpected basic block transform while optimizing select\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 6983, __extension__ __PRETTY_FUNCTION__
));

  FalseBlock = BasicBlock::Create(SI->getContext(), "select.false",
                                  EndBlock->getParent(), EndBlock);
  if (IsHugeFunc)
    FreshBBs.insert(FalseBlock);
  auto *FalseBranch = BranchInst::Create(EndBlock, FalseBlock);
  FalseBranch->setDebugLoc(SI->getDebugLoc());
}

// Insert the real conditional branch based on the original condition.
// If we did not create a new block for one of the 'true' or 'false' paths
// of the condition, it means that side of the branch goes to the end block
// directly and the path originates from the start block from the point of
// view of the new PHI.
BasicBlock *TT, *FT;
if (TrueBlock == nullptr) {
  TT = EndBlock;
  FT = FalseBlock;
  TrueBlock = StartBlock;
} else if (FalseBlock == nullptr) {
  TT = TrueBlock;
  FT = EndBlock;
  FalseBlock = StartBlock;
} else {
  TT = TrueBlock;
  FT = FalseBlock;
}
IRBuilder<> IB(SI);
auto *CondFr = IB.CreateFreeze(SI->getCondition(), SI->getName() + ".frozen");
IB.CreateCondBr(CondFr, TT, FT, SI);

SmallPtrSet<const Instruction *, 2> INS;
INS.insert(ASI.begin(), ASI.end());
// Use reverse iterator because later select may use the value of the
// earlier select, and we need to propagate value through earlier select
// to get the PHI operand.
for (SelectInst *SI : llvm::reverse(ASI)) {
  // The select itself is replaced with a PHI Node.
  PHINode *PN = PHINode::Create(SI->getType(), 2, "", &EndBlock->front());
  PN->takeName(SI);
  PN->addIncoming(getTrueOrFalseValue(SI, true, INS), TrueBlock);
  PN->addIncoming(getTrueOrFalseValue(SI, false, INS), FalseBlock);
  PN->setDebugLoc(SI->getDebugLoc());

  replaceAllUsesWith(SI, PN, FreshBBs, IsHugeFunc);
  SI->eraseFromParent();
  INS.erase(SI);
  ++NumSelectsExpanded;
}

// Instruct OptimizeBlock to skip to the next block.
CurInstIterator = StartBlock->end();
return true;
7037}

7039/// Some targets only accept certain types for splat inputs. For example a VDUP
7040/// in MVE takes a GPR (integer) register, and the instruction that incorporate
7041/// a VDUP (such as a VADD qd, qm, rm) also require a gpr register.
7042bool CodeGenPrepare::optimizeShuffleVectorInst(ShuffleVectorInst *SVI) {
// Accept shuf(insertelem(undef/poison, val, 0), undef/poison, <0,0,..>) only
if (!match(SVI, m_Shuffle(m_InsertElt(m_Undef(), m_Value(), m_ZeroInt()),
                          m_Undef(), m_ZeroMask())))
  return false;
Type *NewType = TLI->shouldConvertSplatType(SVI);
if (!NewType)
  return false;

auto *SVIVecType = cast<FixedVectorType>(SVI->getType());
assert(!NewType->isVectorTy() && "Expected a scalar type!")(static_cast <bool> (!NewType->isVectorTy() &&
 "Expected a scalar type!") ? void (0) : __assert_fail ("!NewType->isVectorTy() && \"Expected a scalar type!\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7052, __extension__ __PRETTY_FUNCTION__
));
assert(NewType->getScalarSizeInBits() == SVIVecType->getScalarSizeInBits() &&(static_cast <bool> (NewType->getScalarSizeInBits() ==
 SVIVecType->getScalarSizeInBits() && "Expected a type of the same size!"
) ? void (0) : __assert_fail ("NewType->getScalarSizeInBits() == SVIVecType->getScalarSizeInBits() && \"Expected a type of the same size!\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7054, __extension__ __PRETTY_FUNCTION__
))
       "Expected a type of the same size!")(static_cast <bool> (NewType->getScalarSizeInBits() ==
 SVIVecType->getScalarSizeInBits() && "Expected a type of the same size!"
) ? void (0) : __assert_fail ("NewType->getScalarSizeInBits() == SVIVecType->getScalarSizeInBits() && \"Expected a type of the same size!\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7054, __extension__ __PRETTY_FUNCTION__
));
auto *NewVecType =
    FixedVectorType::get(NewType, SVIVecType->getNumElements());

// Create a bitcast (shuffle (insert (bitcast(..))))
IRBuilder<> Builder(SVI->getContext());
Builder.SetInsertPoint(SVI);
Value *BC1 = Builder.CreateBitCast(
    cast<Instruction>(SVI->getOperand(0))->getOperand(1), NewType);
Value *Shuffle = Builder.CreateVectorSplat(NewVecType->getNumElements(), BC1);
Value *BC2 = Builder.CreateBitCast(Shuffle, SVIVecType);

replaceAllUsesWith(SVI, BC2, FreshBBs, IsHugeFunc);
RecursivelyDeleteTriviallyDeadInstructions(
    SVI, TLInfo, nullptr,
    [&](Value *V) { removeAllAssertingVHReferences(V); });

// Also hoist the bitcast up to its operand if it they are not in the same
// block.
if (auto *BCI = dyn_cast<Instruction>(BC1))
  if (auto *Op = dyn_cast<Instruction>(BCI->getOperand(0)))
    if (BCI->getParent() != Op->getParent() && !isa<PHINode>(Op) &&
        !Op->isTerminator() && !Op->isEHPad())
      BCI->moveAfter(Op);

return true;
7080}

7082bool CodeGenPrepare::tryToSinkFreeOperands(Instruction *I) {
// If the operands of I can be folded into a target instruction together with
// I, duplicate and sink them.
SmallVector<Use *, 4> OpsToSink;
if (!TLI->shouldSinkOperands(I, OpsToSink))
  return false;

// OpsToSink can contain multiple uses in a use chain (e.g.
// (%u1 with %u1 = shufflevector), (%u2 with %u2 = zext %u1)). The dominating
// uses must come first, so we process the ops in reverse order so as to not
// create invalid IR.
BasicBlock *TargetBB = I->getParent();
bool Changed = false;
SmallVector<Use *, 4> ToReplace;
Instruction *InsertPoint = I;
DenseMap<const Instruction *, unsigned long> InstOrdering;
unsigned long InstNumber = 0;
for (const auto &I : *TargetBB)
  InstOrdering[&I] = InstNumber++;

for (Use *U : reverse(OpsToSink)) {
  auto *UI = cast<Instruction>(U->get());
  if (isa<PHINode>(UI))
    continue;
  if (UI->getParent() == TargetBB) {
    if (InstOrdering[UI] < InstOrdering[InsertPoint])
      InsertPoint = UI;
    continue;
  }
  ToReplace.push_back(U);
}

SetVector<Instruction *> MaybeDead;
DenseMap<Instruction *, Instruction *> NewInstructions;
for (Use *U : ToReplace) {
  auto *UI = cast<Instruction>(U->get());
  Instruction *NI = UI->clone();

  if (IsHugeFunc) {
    // Now we clone an instruction, its operands' defs may sink to this BB
    // now. So we put the operands defs' BBs into FreshBBs to do optmization.
    for (unsigned I = 0; I < NI->getNumOperands(); ++I) {
      auto *OpDef = dyn_cast<Instruction>(NI->getOperand(I));
      if (!OpDef)
        continue;
      FreshBBs.insert(OpDef->getParent());
    }
  }

  NewInstructions[UI] = NI;
  MaybeDead.insert(UI);
  LLVM_DEBUG(dbgs() << "Sinking " << *UI << " to user " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Sinking " << *UI
 << " to user " << *I << "\n"; } } while (false
);
  NI->insertBefore(InsertPoint);
  InsertPoint = NI;
  InsertedInsts.insert(NI);

  // Update the use for the new instruction, making sure that we update the
  // sunk instruction uses, if it is part of a chain that has already been
  // sunk.
  Instruction *OldI = cast<Instruction>(U->getUser());
  if (NewInstructions.count(OldI))
    NewInstructions[OldI]->setOperand(U->getOperandNo(), NI);
  else
    U->set(NI);
  Changed = true;
}

// Remove instructions that are dead after sinking.
for (auto *I : MaybeDead) {
  if (!I->hasNUsesOrMore(1)) {
    LLVM_DEBUG(dbgs() << "Removing dead instruction: " << *I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Removing dead instruction: "
 << *I << "\n"; } } while (false);
    I->eraseFromParent();
  }
}

return Changed;
7158}

7160bool CodeGenPrepare::optimizeSwitchType(SwitchInst *SI) {
Value *Cond = SI->getCondition();
Type *OldType = Cond->getType();
LLVMContext &Context = Cond->getContext();
EVT OldVT = TLI->getValueType(*DL, OldType);
MVT RegType = TLI->getPreferredSwitchConditionType(Context, OldVT);
unsigned RegWidth = RegType.getSizeInBits();

if (RegWidth <= cast<IntegerType>(OldType)->getBitWidth())
  return false;

// If the register width is greater than the type width, expand the condition
// of the switch instruction and each case constant to the width of the
// register. By widening the type of the switch condition, subsequent
// comparisons (for case comparisons) will not need to be extended to the
// preferred register width, so we will potentially eliminate N-1 extends,
// where N is the number of cases in the switch.
auto *NewType = Type::getIntNTy(Context, RegWidth);

// Extend the switch condition and case constants using the target preferred
// extend unless the switch condition is a function argument with an extend
// attribute. In that case, we can avoid an unnecessary mask/extension by
// matching the argument extension instead.
Instruction::CastOps ExtType = Instruction::ZExt;
// Some targets prefer SExt over ZExt.
if (TLI->isSExtCheaperThanZExt(OldVT, RegType))
  ExtType = Instruction::SExt;

if (auto *Arg = dyn_cast<Argument>(Cond)) {
  if (Arg->hasSExtAttr())
    ExtType = Instruction::SExt;
  if (Arg->hasZExtAttr())
    ExtType = Instruction::ZExt;
}

auto *ExtInst = CastInst::Create(ExtType, Cond, NewType);
ExtInst->insertBefore(SI);
ExtInst->setDebugLoc(SI->getDebugLoc());
SI->setCondition(ExtInst);
for (auto Case : SI->cases()) {
  const APInt &NarrowConst = Case.getCaseValue()->getValue();
  APInt WideConst = (ExtType == Instruction::ZExt)
                        ? NarrowConst.zext(RegWidth)
                        : NarrowConst.sext(RegWidth);
  Case.setValue(ConstantInt::get(Context, WideConst));
}

return true;
7208}

7210bool CodeGenPrepare::optimizeSwitchPhiConstants(SwitchInst *SI) {
// The SCCP optimization tends to produce code like this:
//   switch(x) { case 42: phi(42, ...) }
// Materializing the constant for the phi-argument needs instructions; So we
// change the code to:
//   switch(x) { case 42: phi(x, ...) }

Value *Condition = SI->getCondition();
// Avoid endless loop in degenerate case.
if (isa<ConstantInt>(*Condition))
  return false;

bool Changed = false;
BasicBlock *SwitchBB = SI->getParent();
Type *ConditionType = Condition->getType();

for (const SwitchInst::CaseHandle &Case : SI->cases()) {
  ConstantInt *CaseValue = Case.getCaseValue();
  BasicBlock *CaseBB = Case.getCaseSuccessor();
  // Set to true if we previously checked that `CaseBB` is only reached by
  // a single case from this switch.
  bool CheckedForSinglePred = false;
  for (PHINode &PHI : CaseBB->phis()) {
    Type *PHIType = PHI.getType();
    // If ZExt is free then we can also catch patterns like this:
    //   switch((i32)x) { case 42: phi((i64)42, ...); }
    // and replace `(i64)42` with `zext i32 %x to i64`.
    bool TryZExt =
        PHIType->isIntegerTy() &&
        PHIType->getIntegerBitWidth() > ConditionType->getIntegerBitWidth() &&
        TLI->isZExtFree(ConditionType, PHIType);
    if (PHIType == ConditionType || TryZExt) {
      // Set to true to skip this case because of multiple preds.
      bool SkipCase = false;
      Value *Replacement = nullptr;
      for (unsigned I = 0, E = PHI.getNumIncomingValues(); I != E; I++) {
        Value *PHIValue = PHI.getIncomingValue(I);
        if (PHIValue != CaseValue) {
          if (!TryZExt)
            continue;
          ConstantInt *PHIValueInt = dyn_cast<ConstantInt>(PHIValue);
          if (!PHIValueInt ||
              PHIValueInt->getValue() !=
                  CaseValue->getValue().zext(PHIType->getIntegerBitWidth()))
            continue;
        }
        if (PHI.getIncomingBlock(I) != SwitchBB)
          continue;
        // We cannot optimize if there are multiple case labels jumping to
        // this block.  This check may get expensive when there are many
        // case labels so we test for it last.
        if (!CheckedForSinglePred) {
          CheckedForSinglePred = true;
          if (SI->findCaseDest(CaseBB) == nullptr) {
            SkipCase = true;
            break;
          }
        }

        if (Replacement == nullptr) {
          if (PHIValue == CaseValue) {
            Replacement = Condition;
          } else {
            IRBuilder<> Builder(SI);
            Replacement = Builder.CreateZExt(Condition, PHIType);
          }
        }
        PHI.setIncomingValue(I, Replacement);
        Changed = true;
      }
      if (SkipCase)
        break;
    }
  }
}
return Changed;
7286}

7288bool CodeGenPrepare::optimizeSwitchInst(SwitchInst *SI) {
bool Changed = optimizeSwitchType(SI);
Changed |= optimizeSwitchPhiConstants(SI);
return Changed;
7292}

7294namespace {

7296/// Helper class to promote a scalar operation to a vector one.
7297/// This class is used to move downward extractelement transition.
7298/// E.g.,
7299/// a = vector_op <2 x i32>
7300/// b = extractelement <2 x i32> a, i32 0
7301/// c = scalar_op b
7302/// store c
7303///
7304/// =>
7305/// a = vector_op <2 x i32>
7306/// c = vector_op a (equivalent to scalar_op on the related lane)
7307/// * d = extractelement <2 x i32> c, i32 0
7308/// * store d
7309/// Assuming both extractelement and store can be combine, we get rid of the
7310/// transition.
7311class VectorPromoteHelper {
/// DataLayout associated with the current module.
const DataLayout &DL;

/// Used to perform some checks on the legality of vector operations.
const TargetLowering &TLI;

/// Used to estimated the cost of the promoted chain.
const TargetTransformInfo &TTI;

/// The transition being moved downwards.
Instruction *Transition;

/// The sequence of instructions to be promoted.
SmallVector<Instruction *, 4> InstsToBePromoted;

/// Cost of combining a store and an extract.
unsigned StoreExtractCombineCost;

/// Instruction that will be combined with the transition.
Instruction *CombineInst = nullptr;

/// The instruction that represents the current end of the transition.
/// Since we are faking the promotion until we reach the end of the chain
/// of computation, we need a way to get the current end of the transition.
Instruction *getEndOfTransition() const {
  if (InstsToBePromoted.empty())
    return Transition;
  return InstsToBePromoted.back();
}

/// Return the index of the original value in the transition.
/// E.g., for "extractelement <2 x i32> c, i32 1" the original value,
/// c, is at index 0.
unsigned getTransitionOriginalValueIdx() const {
  assert(isa<ExtractElementInst>(Transition) &&(static_cast <bool> (isa<ExtractElementInst>(Transition
) && "Other kind of transitions are not supported yet"
) ? void (0) : __assert_fail ("isa<ExtractElementInst>(Transition) && \"Other kind of transitions are not supported yet\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7347, __extension__ __PRETTY_FUNCTION__
))
         "Other kind of transitions are not supported yet")(static_cast <bool> (isa<ExtractElementInst>(Transition
) && "Other kind of transitions are not supported yet"
) ? void (0) : __assert_fail ("isa<ExtractElementInst>(Transition) && \"Other kind of transitions are not supported yet\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7347, __extension__ __PRETTY_FUNCTION__
));
  return 0;
}

/// Return the index of the index in the transition.
/// E.g., for "extractelement <2 x i32> c, i32 0" the index
/// is at index 1.
unsigned getTransitionIdx() const {
  assert(isa<ExtractElementInst>(Transition) &&(static_cast <bool> (isa<ExtractElementInst>(Transition
) && "Other kind of transitions are not supported yet"
) ? void (0) : __assert_fail ("isa<ExtractElementInst>(Transition) && \"Other kind of transitions are not supported yet\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7356, __extension__ __PRETTY_FUNCTION__
))
         "Other kind of transitions are not supported yet")(static_cast <bool> (isa<ExtractElementInst>(Transition
) && "Other kind of transitions are not supported yet"
) ? void (0) : __assert_fail ("isa<ExtractElementInst>(Transition) && \"Other kind of transitions are not supported yet\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7356, __extension__ __PRETTY_FUNCTION__
));
  return 1;
}

/// Get the type of the transition.
/// This is the type of the original value.
/// E.g., for "extractelement <2 x i32> c, i32 1" the type of the
/// transition is <2 x i32>.
Type *getTransitionType() const {
  return Transition->getOperand(getTransitionOriginalValueIdx())->getType();
}

/// Promote \p ToBePromoted by moving \p Def downward through.
/// I.e., we have the following sequence:
/// Def = Transition <ty1> a to <ty2>
/// b = ToBePromoted <ty2> Def, ...
/// =>
/// b = ToBePromoted <ty1> a, ...
/// Def = Transition <ty1> ToBePromoted to <ty2>
void promoteImpl(Instruction *ToBePromoted);

/// Check whether or not it is profitable to promote all the
/// instructions enqueued to be promoted.
bool isProfitableToPromote() {
  Value *ValIdx = Transition->getOperand(getTransitionOriginalValueIdx());
  unsigned Index = isa<ConstantInt>(ValIdx)
                       ? cast<ConstantInt>(ValIdx)->getZExtValue()
                       : -1;
  Type *PromotedType = getTransitionType();

  StoreInst *ST = cast<StoreInst>(CombineInst);
  unsigned AS = ST->getPointerAddressSpace();
  // Check if this store is supported.
  if (!TLI.allowsMisalignedMemoryAccesses(
          TLI.getValueType(DL, ST->getValueOperand()->getType()), AS,
          ST->getAlign())) {
    // If this is not supported, there is no way we can combine
    // the extract with the store.
    return false;
  }

  // The scalar chain of computation has to pay for the transition
  // scalar to vector.
  // The vector chain has to account for the combining cost.
  enum TargetTransformInfo::TargetCostKind CostKind =
      TargetTransformInfo::TCK_RecipThroughput;
  InstructionCost ScalarCost =
      TTI.getVectorInstrCost(*Transition, PromotedType, CostKind, Index);
  InstructionCost VectorCost = StoreExtractCombineCost;
  for (const auto &Inst : InstsToBePromoted) {
    // Compute the cost.
    // By construction, all instructions being promoted are arithmetic ones.
    // Moreover, one argument is a constant that can be viewed as a splat
    // constant.
    Value *Arg0 = Inst->getOperand(0);
    bool IsArg0Constant = isa<UndefValue>(Arg0) || isa<ConstantInt>(Arg0) ||
                          isa<ConstantFP>(Arg0);
    TargetTransformInfo::OperandValueInfo Arg0Info, Arg1Info;
    if (IsArg0Constant)
      Arg0Info.Kind = TargetTransformInfo::OK_UniformConstantValue;
    else
      Arg1Info.Kind = TargetTransformInfo::OK_UniformConstantValue;

    ScalarCost += TTI.getArithmeticInstrCost(
        Inst->getOpcode(), Inst->getType(), CostKind, Arg0Info, Arg1Info);
    VectorCost += TTI.getArithmeticInstrCost(Inst->getOpcode(), PromotedType,
                                             CostKind, Arg0Info, Arg1Info);
  }
  LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Estimated cost of computation to be promoted:\nScalar: "
 << ScalarCost << "\nVector: " << VectorCost
 << '\n'; } } while (false)
      dbgs() << "Estimated cost of computation to be promoted:\nScalar: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Estimated cost of computation to be promoted:\nScalar: "
 << ScalarCost << "\nVector: " << VectorCost
 << '\n'; } } while (false)
             << ScalarCost << "\nVector: " << VectorCost << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Estimated cost of computation to be promoted:\nScalar: "
 << ScalarCost << "\nVector: " << VectorCost
 << '\n'; } } while (false);
  return ScalarCost > VectorCost;
}

/// Generate a constant vector with \p Val with the same
/// number of elements as the transition.
/// \p UseSplat defines whether or not \p Val should be replicated
/// across the whole vector.
/// In other words, if UseSplat == true, we generate <Val, Val, ..., Val>,
/// otherwise we generate a vector with as many undef as possible:
/// <undef, ..., undef, Val, undef, ..., undef> where \p Val is only
/// used at the index of the extract.
Value *getConstantVector(Constant *Val, bool UseSplat) const {
  unsigned ExtractIdx = std::numeric_limits<unsigned>::max();
  if (!UseSplat) {
    // If we cannot determine where the constant must be, we have to
    // use a splat constant.
    Value *ValExtractIdx = Transition->getOperand(getTransitionIdx());
    if (ConstantInt *CstVal = dyn_cast<ConstantInt>(ValExtractIdx))
      ExtractIdx = CstVal->getSExtValue();
    else
      UseSplat = true;
  }

  ElementCount EC = cast<VectorType>(getTransitionType())->getElementCount();
  if (UseSplat)
    return ConstantVector::getSplat(EC, Val);

  if (!EC.isScalable()) {
    SmallVector<Constant *, 4> ConstVec;
    UndefValue *UndefVal = UndefValue::get(Val->getType());
    for (unsigned Idx = 0; Idx != EC.getKnownMinValue(); ++Idx) {
      if (Idx == ExtractIdx)
        ConstVec.push_back(Val);
      else
        ConstVec.push_back(UndefVal);
    }
    return ConstantVector::get(ConstVec);
  } else
    llvm_unreachable(::llvm::llvm_unreachable_internal("Generate scalable vector for non-splat is unimplemented"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7466)
        "Generate scalable vector for non-splat is unimplemented")::llvm::llvm_unreachable_internal("Generate scalable vector for non-splat is unimplemented"
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7466);
}

/// Check if promoting to a vector type an operand at \p OperandIdx
/// in \p Use can trigger undefined behavior.
static bool canCauseUndefinedBehavior(const Instruction *Use,
                                      unsigned OperandIdx) {
  // This is not safe to introduce undef when the operand is on
  // the right hand side of a division-like instruction.
  if (OperandIdx != 1)
    return false;
  switch (Use->getOpcode()) {
  default:
    return false;
  case Instruction::SDiv:
  case Instruction::UDiv:
  case Instruction::SRem:
  case Instruction::URem:
    return true;
  case Instruction::FDiv:
  case Instruction::FRem:
    return !Use->hasNoNaNs();
  }
  llvm_unreachable(nullptr)::llvm::llvm_unreachable_internal(nullptr, "llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 7489);
}

7492public:
VectorPromoteHelper(const DataLayout &DL, const TargetLowering &TLI,
                    const TargetTransformInfo &TTI, Instruction *Transition,
                    unsigned CombineCost)
    : DL(DL), TLI(TLI), TTI(TTI), Transition(Transition),
      StoreExtractCombineCost(CombineCost) {
  assert(Transition && "Do not know how to promote null")(static_cast <bool> (Transition && "Do not know how to promote null"
) ? void (0) : __assert_fail ("Transition && \"Do not know how to promote null\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7498, __extension__ __PRETTY_FUNCTION__
));
}

/// Check if we can promote \p ToBePromoted to \p Type.
bool canPromote(const Instruction *ToBePromoted) const {
  // We could support CastInst too.
  return isa<BinaryOperator>(ToBePromoted);
}

/// Check if it is profitable to promote \p ToBePromoted
/// by moving downward the transition through.
bool shouldPromote(const Instruction *ToBePromoted) const {
  // Promote only if all the operands can be statically expanded.
  // Indeed, we do not want to introduce any new kind of transitions.
  for (const Use &U : ToBePromoted->operands()) {
    const Value *Val = U.get();
    if (Val == getEndOfTransition()) {
      // If the use is a division and the transition is on the rhs,
      // we cannot promote the operation, otherwise we may create a
      // division by zero.
      if (canCauseUndefinedBehavior(ToBePromoted, U.getOperandNo()))
        return false;
      continue;
    }
    if (!isa<ConstantInt>(Val) && !isa<UndefValue>(Val) &&
        !isa<ConstantFP>(Val))
      return false;
  }
  // Check that the resulting operation is legal.
  int ISDOpcode = TLI.InstructionOpcodeToISD(ToBePromoted->getOpcode());
  if (!ISDOpcode)
    return false;
  return StressStoreExtract ||
         TLI.isOperationLegalOrCustom(
             ISDOpcode, TLI.getValueType(DL, getTransitionType(), true));
}

/// Check whether or not \p Use can be combined
/// with the transition.
/// I.e., is it possible to do Use(Transition) => AnotherUse?
bool canCombine(const Instruction *Use) { return isa<StoreInst>(Use); }

/// Record \p ToBePromoted as part of the chain to be promoted.
void enqueueForPromotion(Instruction *ToBePromoted) {
  InstsToBePromoted.push_back(ToBePromoted);
}

/// Set the instruction that will be combined with the transition.
void recordCombineInstruction(Instruction *ToBeCombined) {
  assert(canCombine(ToBeCombined) && "Unsupported instruction to combine")(static_cast <bool> (canCombine(ToBeCombined) &&
 "Unsupported instruction to combine") ? void (0) : __assert_fail
 ("canCombine(ToBeCombined) && \"Unsupported instruction to combine\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7547, __extension__ __PRETTY_FUNCTION__
));
  CombineInst = ToBeCombined;
}

/// Promote all the instructions enqueued for promotion if it is
/// is profitable.
/// \return True if the promotion happened, false otherwise.
bool promote() {
  // Check if there is something to promote.
  // Right now, if we do not have anything to combine with,
  // we assume the promotion is not profitable.
  if (InstsToBePromoted.empty() || !CombineInst)
    return false;

  // Check cost.
  if (!StressStoreExtract && !isProfitableToPromote())
    return false;

  // Promote.
  for (auto &ToBePromoted : InstsToBePromoted)
    promoteImpl(ToBePromoted);
  InstsToBePromoted.clear();
  return true;
}
7571};

7573} // end anonymous namespace

7575void VectorPromoteHelper::promoteImpl(Instruction *ToBePromoted) {
// At this point, we know that all the operands of ToBePromoted but Def
// can be statically promoted.
// For Def, we need to use its parameter in ToBePromoted:
// b = ToBePromoted ty1 a
// Def = Transition ty1 b to ty2
// Move the transition down.
// 1. Replace all uses of the promoted operation by the transition.
// = ... b => = ... Def.
assert(ToBePromoted->getType() == Transition->getType() &&(static_cast <bool> (ToBePromoted->getType() == Transition
->getType() && "The type of the result of the transition does not match "
 "the final type") ? void (0) : __assert_fail ("ToBePromoted->getType() == Transition->getType() && \"The type of the result of the transition does not match \" \"the final type\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7586, __extension__ __PRETTY_FUNCTION__
))
       "The type of the result of the transition does not match "(static_cast <bool> (ToBePromoted->getType() == Transition
->getType() && "The type of the result of the transition does not match "
 "the final type") ? void (0) : __assert_fail ("ToBePromoted->getType() == Transition->getType() && \"The type of the result of the transition does not match \" \"the final type\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7586, __extension__ __PRETTY_FUNCTION__
))
       "the final type")(static_cast <bool> (ToBePromoted->getType() == Transition
->getType() && "The type of the result of the transition does not match "
 "the final type") ? void (0) : __assert_fail ("ToBePromoted->getType() == Transition->getType() && \"The type of the result of the transition does not match \" \"the final type\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7586, __extension__ __PRETTY_FUNCTION__
));
ToBePromoted->replaceAllUsesWith(Transition);
// 2. Update the type of the uses.
// b = ToBePromoted ty2 Def => b = ToBePromoted ty1 Def.
Type *TransitionTy = getTransitionType();
ToBePromoted->mutateType(TransitionTy);
// 3. Update all the operands of the promoted operation with promoted
// operands.
// b = ToBePromoted ty1 Def => b = ToBePromoted ty1 a.
for (Use &U : ToBePromoted->operands()) {
  Value *Val = U.get();
  Value *NewVal = nullptr;
  if (Val == Transition)
    NewVal = Transition->getOperand(getTransitionOriginalValueIdx());
  else if (isa<UndefValue>(Val) || isa<ConstantInt>(Val) ||
           isa<ConstantFP>(Val)) {
    // Use a splat constant if it is not safe to use undef.
    NewVal = getConstantVector(
        cast<Constant>(Val),
        isa<UndefValue>(Val) ||
            canCauseUndefinedBehavior(ToBePromoted, U.getOperandNo()));
  } else
    llvm_unreachable("Did you modified shouldPromote and forgot to update "::llvm::llvm_unreachable_internal("Did you modified shouldPromote and forgot to update "
 "this?", "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7609)
                     "this?")::llvm::llvm_unreachable_internal("Did you modified shouldPromote and forgot to update "
 "this?", "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7609);
  ToBePromoted->setOperand(U.getOperandNo(), NewVal);
}
Transition->moveAfter(ToBePromoted);
Transition->setOperand(getTransitionOriginalValueIdx(), ToBePromoted);
7614}

7616/// Some targets can do store(extractelement) with one instruction.
7617/// Try to push the extractelement towards the stores when the target
7618/// has this feature and this is profitable.
7619bool CodeGenPrepare::optimizeExtractElementInst(Instruction *Inst) {
unsigned CombineCost = std::numeric_limits<unsigned>::max();
if (DisableStoreExtract ||
    (!StressStoreExtract &&
     !TLI->canCombineStoreAndExtract(Inst->getOperand(0)->getType(),
                                     Inst->getOperand(1), CombineCost)))
  return false;

// At this point we know that Inst is a vector to scalar transition.
// Try to move it down the def-use chain, until:
// - We can combine the transition with its single use
//   => we got rid of the transition.
// - We escape the current basic block
//   => we would need to check that we are moving it at a cheaper place and
//      we do not do that for now.
BasicBlock *Parent = Inst->getParent();
LLVM_DEBUG(dbgs() << "Found an interesting transition: " << *Inst << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Found an interesting transition: "
 << *Inst << '\n'; } } while (false);
VectorPromoteHelper VPH(*DL, *TLI, *TTI, Inst, CombineCost);
// If the transition has more than one use, assume this is not going to be
// beneficial.
while (Inst->hasOneUse()) {
  Instruction *ToBePromoted = cast<Instruction>(*Inst->user_begin());
  LLVM_DEBUG(dbgs() << "Use: " << *ToBePromoted << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Use: " << *ToBePromoted
 << '\n'; } } while (false);

  if (ToBePromoted->getParent() != Parent) {
    LLVM_DEBUG(dbgs() << "Instruction to promote is in a different block ("do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Instruction to promote is in a different block ("
 << ToBePromoted->getParent()->getName() <<
 ") than the transition (" << Parent->getName() <<
 ").\n"; } } while (false)
                      << ToBePromoted->getParent()->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Instruction to promote is in a different block ("
 << ToBePromoted->getParent()->getName() <<
 ") than the transition (" << Parent->getName() <<
 ").\n"; } } while (false)
                      << ") than the transition (" << Parent->getName()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Instruction to promote is in a different block ("
 << ToBePromoted->getParent()->getName() <<
 ") than the transition (" << Parent->getName() <<
 ").\n"; } } while (false)
                      << ").\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Instruction to promote is in a different block ("
 << ToBePromoted->getParent()->getName() <<
 ") than the transition (" << Parent->getName() <<
 ").\n"; } } while (false);
    return false;
  }

  if (VPH.canCombine(ToBePromoted)) {
    LLVM_DEBUG(dbgs() << "Assume " << *Inst << '\n'do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Assume " << *Inst
 << '\n' << "will be combined with: " << *ToBePromoted
 << '\n'; } } while (false)
                      << "will be combined with: " << *ToBePromoted << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Assume " << *Inst
 << '\n' << "will be combined with: " << *ToBePromoted
 << '\n'; } } while (false);
    VPH.recordCombineInstruction(ToBePromoted);
    bool Changed = VPH.promote();
    NumStoreExtractExposed += Changed;
    return Changed;
  }

  LLVM_DEBUG(dbgs() << "Try promoting.\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Try promoting.\n"; } }
 while (false);
  if (!VPH.canPromote(ToBePromoted) || !VPH.shouldPromote(ToBePromoted))
    return false;

  LLVM_DEBUG(dbgs() << "Promoting is possible... Enqueue for promotion!\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Promoting is possible... Enqueue for promotion!\n"
; } } while (false);

  VPH.enqueueForPromotion(ToBePromoted);
  Inst = ToBePromoted;
}
return false;
7670}

7672/// For the instruction sequence of store below, F and I values
7673/// are bundled together as an i64 value before being stored into memory.
7674/// Sometimes it is more efficient to generate separate stores for F and I,
7675/// which can remove the bitwise instructions or sink them to colder places.
7676///
7677///   (store (or (zext (bitcast F to i32) to i64),
7678///              (shl (zext I to i64), 32)), addr)  -->
7679///   (store F, addr) and (store I, addr+4)
7680///
7681/// Similarly, splitting for other merged store can also be beneficial, like:
7682/// For pair of {i32, i32}, i64 store --> two i32 stores.
7683/// For pair of {i32, i16}, i64 store --> two i32 stores.
7684/// For pair of {i16, i16}, i32 store --> two i16 stores.
7685/// For pair of {i16, i8},  i32 store --> two i16 stores.
7686/// For pair of {i8, i8},   i16 store --> two i8 stores.
7687///
7688/// We allow each target to determine specifically which kind of splitting is
7689/// supported.
7690///
7691/// The store patterns are commonly seen from the simple code snippet below
7692/// if only std::make_pair(...) is sroa transformed before inlined into hoo.
7693///   void goo(const std::pair<int, float> &);
7694///   hoo() {
7695///     ...
7696///     goo(std::make_pair(tmp, ftmp));
7697///     ...
7698///   }
7699///
7700/// Although we already have similar splitting in DAG Combine, we duplicate
7701/// it in CodeGenPrepare to catch the case in which pattern is across
7702/// multiple BBs. The logic in DAG Combine is kept to catch case generated
7703/// during code expansion.
7704static bool splitMergedValStore(StoreInst &SI, const DataLayout &DL,
                              const TargetLowering &TLI) {
// Handle simple but common cases only.
Type *StoreType = SI.getValueOperand()->getType();

// The code below assumes shifting a value by <number of bits>,
// whereas scalable vectors would have to be shifted by
// <2log(vscale) + number of bits> in order to store the
// low/high parts. Bailing out for now.
if (StoreType->isScalableTy())
  return false;

if (!DL.typeSizeEqualsStoreSize(StoreType) ||
    DL.getTypeSizeInBits(StoreType) == 0)
  return false;

unsigned HalfValBitSize = DL.getTypeSizeInBits(StoreType) / 2;
Type *SplitStoreType = Type::getIntNTy(SI.getContext(), HalfValBitSize);
if (!DL.typeSizeEqualsStoreSize(SplitStoreType))
  return false;

// Don't split the store if it is volatile.
if (SI.isVolatile())
  return false;

// Match the following patterns:
// (store (or (zext LValue to i64),
//            (shl (zext HValue to i64), 32)), HalfValBitSize)
//  or
// (store (or (shl (zext HValue to i64), 32)), HalfValBitSize)
//            (zext LValue to i64),
// Expect both operands of OR and the first operand of SHL have only
// one use.
Value *LValue, *HValue;
if (!match(SI.getValueOperand(),
           m_c_Or(m_OneUse(m_ZExt(m_Value(LValue))),
                  m_OneUse(m_Shl(m_OneUse(m_ZExt(m_Value(HValue))),
                                 m_SpecificInt(HalfValBitSize))))))
  return false;

// Check LValue and HValue are int with size less or equal than 32.
if (!LValue->getType()->isIntegerTy() ||
    DL.getTypeSizeInBits(LValue->getType()) > HalfValBitSize ||
    !HValue->getType()->isIntegerTy() ||
    DL.getTypeSizeInBits(HValue->getType()) > HalfValBitSize)
  return false;

// If LValue/HValue is a bitcast instruction, use the EVT before bitcast
// as the input of target query.
auto *LBC = dyn_cast<BitCastInst>(LValue);
auto *HBC = dyn_cast<BitCastInst>(HValue);
EVT LowTy = LBC ? EVT::getEVT(LBC->getOperand(0)->getType())
                : EVT::getEVT(LValue->getType());
EVT HighTy = HBC ? EVT::getEVT(HBC->getOperand(0)->getType())
                 : EVT::getEVT(HValue->getType());
if (!ForceSplitStore && !TLI.isMultiStoresCheaperThanBitsMerge(LowTy, HighTy))
  return false;

// Start to split store.
IRBuilder<> Builder(SI.getContext());
Builder.SetInsertPoint(&SI);

// If LValue/HValue is a bitcast in another BB, create a new one in current
// BB so it may be merged with the splitted stores by dag combiner.
if (LBC && LBC->getParent() != SI.getParent())
  LValue = Builder.CreateBitCast(LBC->getOperand(0), LBC->getType());
if (HBC && HBC->getParent() != SI.getParent())
  HValue = Builder.CreateBitCast(HBC->getOperand(0), HBC->getType());

bool IsLE = SI.getModule()->getDataLayout().isLittleEndian();
auto CreateSplitStore = [&](Value *V, bool Upper) {
  V = Builder.CreateZExtOrBitCast(V, SplitStoreType);
  Value *Addr = Builder.CreateBitCast(
      SI.getOperand(1),
      SplitStoreType->getPointerTo(SI.getPointerAddressSpace()));
  Align Alignment = SI.getAlign();
  const bool IsOffsetStore = (IsLE && Upper) || (!IsLE && !Upper);
  if (IsOffsetStore) {
    Addr = Builder.CreateGEP(
        SplitStoreType, Addr,
        ConstantInt::get(Type::getInt32Ty(SI.getContext()), 1));

    // When splitting the store in half, naturally one half will retain the
    // alignment of the original wider store, regardless of whether it was
    // over-aligned or not, while the other will require adjustment.
    Alignment = commonAlignment(Alignment, HalfValBitSize / 8);
  }
  Builder.CreateAlignedStore(V, Addr, Alignment);
};

CreateSplitStore(LValue, false);
CreateSplitStore(HValue, true);

// Delete the old store.
SI.eraseFromParent();
return true;
7800}

7802// Return true if the GEP has two operands, the first operand is of a sequential
7803// type, and the second operand is a constant.
7804static bool GEPSequentialConstIndexed(GetElementPtrInst *GEP) {
gep_type_iterator I = gep_type_begin(*GEP);
return GEP->getNumOperands() == 2 && I.isSequential() &&
       isa<ConstantInt>(GEP->getOperand(1));
7808}

7810// Try unmerging GEPs to reduce liveness interference (register pressure) across
7811// IndirectBr edges. Since IndirectBr edges tend to touch on many blocks,
7812// reducing liveness interference across those edges benefits global register
7813// allocation. Currently handles only certain cases.
7814//
7815// For example, unmerge %GEPI and %UGEPI as below.
7816//
7817// ---------- BEFORE ----------
7818// SrcBlock:
7819//   ...
7820//   %GEPIOp = ...
7821//   ...
7822//   %GEPI = gep %GEPIOp, Idx
7823//   ...
7824//   indirectbr ... [ label %DstB0, label %DstB1, ... label %DstBi ... ]
7825//   (* %GEPI is alive on the indirectbr edges due to other uses ahead)
7826//   (* %GEPIOp is alive on the indirectbr edges only because of it's used by
7827//   %UGEPI)
7828//
7829// DstB0: ... (there may be a gep similar to %UGEPI to be unmerged)
7830// DstB1: ... (there may be a gep similar to %UGEPI to be unmerged)
7831// ...
7832//
7833// DstBi:
7834//   ...
7835//   %UGEPI = gep %GEPIOp, UIdx
7836// ...
7837// ---------------------------
7838//
7839// ---------- AFTER ----------
7840// SrcBlock:
7841//   ... (same as above)
7842//    (* %GEPI is still alive on the indirectbr edges)
7843//    (* %GEPIOp is no longer alive on the indirectbr edges as a result of the
7844//    unmerging)
7845// ...
7846//
7847// DstBi:
7848//   ...
7849//   %UGEPI = gep %GEPI, (UIdx-Idx)
7850//   ...
7851// ---------------------------
7852//
7853// The register pressure on the IndirectBr edges is reduced because %GEPIOp is
7854// no longer alive on them.
7855//
7856// We try to unmerge GEPs here in CodGenPrepare, as opposed to limiting merging
7857// of GEPs in the first place in InstCombiner::visitGetElementPtrInst() so as
7858// not to disable further simplications and optimizations as a result of GEP
7859// merging.
7860//
7861// Note this unmerging may increase the length of the data flow critical path
7862// (the path from %GEPIOp to %UGEPI would go through %GEPI), which is a tradeoff
7863// between the register pressure and the length of data-flow critical
7864// path. Restricting this to the uncommon IndirectBr case would minimize the
7865// impact of potentially longer critical path, if any, and the impact on compile
7866// time.
7867static bool tryUnmergingGEPsAcrossIndirectBr(GetElementPtrInst *GEPI,
                                           const TargetTransformInfo *TTI) {
BasicBlock *SrcBlock = GEPI->getParent();
// Check that SrcBlock ends with an IndirectBr. If not, give up. The common
// (non-IndirectBr) cases exit early here.
if (!isa<IndirectBrInst>(SrcBlock->getTerminator()))
  return false;
// Check that GEPI is a simple gep with a single constant index.
if (!GEPSequentialConstIndexed(GEPI))
  return false;
ConstantInt *GEPIIdx = cast<ConstantInt>(GEPI->getOperand(1));
// Check that GEPI is a cheap one.
if (TTI->getIntImmCost(GEPIIdx->getValue(), GEPIIdx->getType(),
                       TargetTransformInfo::TCK_SizeAndLatency) >
    TargetTransformInfo::TCC_Basic)
  return false;
Value *GEPIOp = GEPI->getOperand(0);
// Check that GEPIOp is an instruction that's also defined in SrcBlock.
if (!isa<Instruction>(GEPIOp))
  return false;
auto *GEPIOpI = cast<Instruction>(GEPIOp);
if (GEPIOpI->getParent() != SrcBlock)
  return false;
// Check that GEP is used outside the block, meaning it's alive on the
// IndirectBr edge(s).
if (llvm::none_of(GEPI->users(), [&](User *Usr) {
      if (auto *I = dyn_cast<Instruction>(Usr)) {
        if (I->getParent() != SrcBlock) {
          return true;
        }
      }
      return false;
    }))
  return false;
// The second elements of the GEP chains to be unmerged.
std::vector<GetElementPtrInst *> UGEPIs;
// Check each user of GEPIOp to check if unmerging would make GEPIOp not alive
// on IndirectBr edges.
for (User *Usr : GEPIOp->users()) {
  if (Usr == GEPI)
    continue;
  // Check if Usr is an Instruction. If not, give up.
  if (!isa<Instruction>(Usr))
    return false;
  auto *UI = cast<Instruction>(Usr);
  // Check if Usr in the same block as GEPIOp, which is fine, skip.
  if (UI->getParent() == SrcBlock)
    continue;
  // Check if Usr is a GEP. If not, give up.
  if (!isa<GetElementPtrInst>(Usr))
    return false;
  auto *UGEPI = cast<GetElementPtrInst>(Usr);
  // Check if UGEPI is a simple gep with a single constant index and GEPIOp is
  // the pointer operand to it. If so, record it in the vector. If not, give
  // up.
  if (!GEPSequentialConstIndexed(UGEPI))
    return false;
  if (UGEPI->getOperand(0) != GEPIOp)
    return false;
  if (GEPIIdx->getType() !=
      cast<ConstantInt>(UGEPI->getOperand(1))->getType())
    return false;
  ConstantInt *UGEPIIdx = cast<ConstantInt>(UGEPI->getOperand(1));
  if (TTI->getIntImmCost(UGEPIIdx->getValue(), UGEPIIdx->getType(),
                         TargetTransformInfo::TCK_SizeAndLatency) >
      TargetTransformInfo::TCC_Basic)
    return false;
  UGEPIs.push_back(UGEPI);
}
if (UGEPIs.size() == 0)
  return false;
// Check the materializing cost of (Uidx-Idx).
for (GetElementPtrInst *UGEPI : UGEPIs) {
  ConstantInt *UGEPIIdx = cast<ConstantInt>(UGEPI->getOperand(1));
  APInt NewIdx = UGEPIIdx->getValue() - GEPIIdx->getValue();
  InstructionCost ImmCost = TTI->getIntImmCost(
      NewIdx, GEPIIdx->getType(), TargetTransformInfo::TCK_SizeAndLatency);
  if (ImmCost > TargetTransformInfo::TCC_Basic)
    return false;
}
// Now unmerge between GEPI and UGEPIs.
for (GetElementPtrInst *UGEPI : UGEPIs) {
  UGEPI->setOperand(0, GEPI);
  ConstantInt *UGEPIIdx = cast<ConstantInt>(UGEPI->getOperand(1));
  Constant *NewUGEPIIdx = ConstantInt::get(
      GEPIIdx->getType(), UGEPIIdx->getValue() - GEPIIdx->getValue());
  UGEPI->setOperand(1, NewUGEPIIdx);
  // If GEPI is not inbounds but UGEPI is inbounds, change UGEPI to not
  // inbounds to avoid UB.
  if (!GEPI->isInBounds()) {
    UGEPI->setIsInBounds(false);
  }
}
// After unmerging, verify that GEPIOp is actually only used in SrcBlock (not
// alive on IndirectBr edges).
assert(llvm::none_of(GEPIOp->users(),(static_cast <bool> (llvm::none_of(GEPIOp->users(), [
&](User *Usr) { return cast<Instruction>(Usr)->getParent
() != SrcBlock; }) && "GEPIOp is used outside SrcBlock"
) ? void (0) : __assert_fail ("llvm::none_of(GEPIOp->users(), [&](User *Usr) { return cast<Instruction>(Usr)->getParent() != SrcBlock; }) && \"GEPIOp is used outside SrcBlock\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7966, __extension__ __PRETTY_FUNCTION__
))
                     [&](User *Usr) {(static_cast <bool> (llvm::none_of(GEPIOp->users(), [
&](User *Usr) { return cast<Instruction>(Usr)->getParent
() != SrcBlock; }) && "GEPIOp is used outside SrcBlock"
) ? void (0) : __assert_fail ("llvm::none_of(GEPIOp->users(), [&](User *Usr) { return cast<Instruction>(Usr)->getParent() != SrcBlock; }) && \"GEPIOp is used outside SrcBlock\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7966, __extension__ __PRETTY_FUNCTION__
))
                       return cast<Instruction>(Usr)->getParent() != SrcBlock;(static_cast <bool> (llvm::none_of(GEPIOp->users(), [
&](User *Usr) { return cast<Instruction>(Usr)->getParent
() != SrcBlock; }) && "GEPIOp is used outside SrcBlock"
) ? void (0) : __assert_fail ("llvm::none_of(GEPIOp->users(), [&](User *Usr) { return cast<Instruction>(Usr)->getParent() != SrcBlock; }) && \"GEPIOp is used outside SrcBlock\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7966, __extension__ __PRETTY_FUNCTION__
))
                     }) &&(static_cast <bool> (llvm::none_of(GEPIOp->users(), [
&](User *Usr) { return cast<Instruction>(Usr)->getParent
() != SrcBlock; }) && "GEPIOp is used outside SrcBlock"
) ? void (0) : __assert_fail ("llvm::none_of(GEPIOp->users(), [&](User *Usr) { return cast<Instruction>(Usr)->getParent() != SrcBlock; }) && \"GEPIOp is used outside SrcBlock\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7966, __extension__ __PRETTY_FUNCTION__
))
       "GEPIOp is used outside SrcBlock")(static_cast <bool> (llvm::none_of(GEPIOp->users(), [
&](User *Usr) { return cast<Instruction>(Usr)->getParent
() != SrcBlock; }) && "GEPIOp is used outside SrcBlock"
) ? void (0) : __assert_fail ("llvm::none_of(GEPIOp->users(), [&](User *Usr) { return cast<Instruction>(Usr)->getParent() != SrcBlock; }) && \"GEPIOp is used outside SrcBlock\""
, "llvm/lib/CodeGen/CodeGenPrepare.cpp", 7966, __extension__ __PRETTY_FUNCTION__
));
return true;
7968}

7970static bool optimizeBranch(BranchInst *Branch, const TargetLowering &TLI,
                         SmallSet<BasicBlock *, 32> &FreshBBs,
                         bool IsHugeFunc) {
// Try and convert
//  %c = icmp ult %x, 8
//  br %c, bla, blb
//  %tc = lshr %x, 3
// to
//  %tc = lshr %x, 3
//  %c = icmp eq %tc, 0
//  br %c, bla, blb
// Creating the cmp to zero can be better for the backend, especially if the
// lshr produces flags that can be used automatically.
if (!TLI.preferZeroCompareBranch() || !Branch->isConditional())
  return false;

ICmpInst *Cmp = dyn_cast<ICmpInst>(Branch->getCondition());
if (!Cmp || !isa<ConstantInt>(Cmp->getOperand(1)) || !Cmp->hasOneUse())
  return false;

Value *X = Cmp->getOperand(0);
APInt CmpC = cast<ConstantInt>(Cmp->getOperand(1))->getValue();

for (auto *U : X->users()) {
  Instruction *UI = dyn_cast<Instruction>(U);
  // A quick dominance check
  if (!UI ||
      (UI->getParent() != Branch->getParent() &&
       UI->getParent() != Branch->getSuccessor(0) &&
       UI->getParent() != Branch->getSuccessor(1)) ||
      (UI->getParent() != Branch->getParent() &&
       !UI->getParent()->getSinglePredecessor()))
    continue;

  if (CmpC.isPowerOf2() && Cmp->getPredicate() == ICmpInst::ICMP_ULT &&
      match(UI, m_Shr(m_Specific(X), m_SpecificInt(CmpC.logBase2())))) {
    IRBuilder<> Builder(Branch);
    if (UI->getParent() != Branch->getParent())
      UI->moveBefore(Branch);
    Value *NewCmp = Builder.CreateCmp(ICmpInst::ICMP_EQ, UI,
                                      ConstantInt::get(UI->getType(), 0));
    LLVM_DEBUG(dbgs() << "Converting " << *Cmp << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Converting " << *
Cmp << "\n"; } } while (false);
    LLVM_DEBUG(dbgs() << " to compare on zero: " << *NewCmp << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << " to compare on zero: "
 << *NewCmp << "\n"; } } while (false);
    replaceAllUsesWith(Cmp, NewCmp, FreshBBs, IsHugeFunc);
    return true;
  }
  if (Cmp->isEquality() &&
      (match(UI, m_Add(m_Specific(X), m_SpecificInt(-CmpC))) ||
       match(UI, m_Sub(m_Specific(X), m_SpecificInt(CmpC))))) {
    IRBuilder<> Builder(Branch);
    if (UI->getParent() != Branch->getParent())
      UI->moveBefore(Branch);
    Value *NewCmp = Builder.CreateCmp(Cmp->getPredicate(), UI,
                                      ConstantInt::get(UI->getType(), 0));
    LLVM_DEBUG(dbgs() << "Converting " << *Cmp << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Converting " << *
Cmp << "\n"; } } while (false);
    LLVM_DEBUG(dbgs() << " to compare on zero: " << *NewCmp << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << " to compare on zero: "
 << *NewCmp << "\n"; } } while (false);
    replaceAllUsesWith(Cmp, NewCmp, FreshBBs, IsHugeFunc);
    return true;
  }
}
return false;
8031}

8033bool CodeGenPrepare::optimizeInst(Instruction *I, ModifyDT &ModifiedDT) {
// Bail out if we inserted the instruction to prevent optimizations from
// stepping on each other's toes.
if (InsertedInsts.count(I))
  return false;

// TODO: Move into the switch on opcode below here.
if (PHINode *P = dyn_cast<PHINode>(I)) {
  // It is possible for very late stage optimizations (such as SimplifyCFG)
  // to introduce PHI nodes too late to be cleaned up.  If we detect such a
  // trivial PHI, go ahead and zap it here.
  if (Value *V = simplifyInstruction(P, {*DL, TLInfo})) {
    LargeOffsetGEPMap.erase(P);
    replaceAllUsesWith(P, V, FreshBBs, IsHugeFunc);
    P->eraseFromParent();
    ++NumPHIsElim;
    return true;
  }
  return false;
}

if (CastInst *CI = dyn_cast<CastInst>(I)) {
  // If the source of the cast is a constant, then this should have
  // already been constant folded.  The only reason NOT to constant fold
  // it is if something (e.g. LSR) was careful to place the constant
  // evaluation in a block other than then one that uses it (e.g. to hoist
  // the address of globals out of a loop).  If this is the case, we don't
  // want to forward-subst the cast.
  if (isa<Constant>(CI->getOperand(0)))
    return false;

  if (OptimizeNoopCopyExpression(CI, *TLI, *DL))
    return true;

  if ((isa<UIToFPInst>(I) || isa<FPToUIInst>(I) || isa<TruncInst>(I)) &&
      TLI->optimizeExtendOrTruncateConversion(I,
                                              LI->getLoopFor(I->getParent())))
    return true;

  if (isa<ZExtInst>(I) || isa<SExtInst>(I)) {
    /// Sink a zext or sext into its user blocks if the target type doesn't
    /// fit in one register
    if (TLI->getTypeAction(CI->getContext(),
                           TLI->getValueType(*DL, CI->getType())) ==
        TargetLowering::TypeExpandInteger) {
      return SinkCast(CI);
    } else {
      if (TLI->optimizeExtendOrTruncateConversion(
              I, LI->getLoopFor(I->getParent())))
        return true;

      bool MadeChange = optimizeExt(I);
      return MadeChange | optimizeExtUses(I);
    }
  }
  return false;
}

if (auto *Cmp = dyn_cast<CmpInst>(I))
  if (optimizeCmp(Cmp, ModifiedDT))
    return true;

if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
  LI->setMetadata(LLVMContext::MD_invariant_group, nullptr);
  bool Modified = optimizeLoadExt(LI);
  unsigned AS = LI->getPointerAddressSpace();
  Modified |= optimizeMemoryInst(I, I->getOperand(0), LI->getType(), AS);
  return Modified;
}

if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
  if (splitMergedValStore(*SI, *DL, *TLI))
    return true;
  SI->setMetadata(LLVMContext::MD_invariant_group, nullptr);
  unsigned AS = SI->getPointerAddressSpace();
  return optimizeMemoryInst(I, SI->getOperand(1),
                            SI->getOperand(0)->getType(), AS);
}

if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
  unsigned AS = RMW->getPointerAddressSpace();
  return optimizeMemoryInst(I, RMW->getPointerOperand(), RMW->getType(), AS);
}

if (AtomicCmpXchgInst *CmpX = dyn_cast<AtomicCmpXchgInst>(I)) {
  unsigned AS = CmpX->getPointerAddressSpace();
  return optimizeMemoryInst(I, CmpX->getPointerOperand(),
                            CmpX->getCompareOperand()->getType(), AS);
}

BinaryOperator *BinOp = dyn_cast<BinaryOperator>(I);

if (BinOp && BinOp->getOpcode() == Instruction::And && EnableAndCmpSinking &&
    sinkAndCmp0Expression(BinOp, *TLI, InsertedInsts))
  return true;

// TODO: Move this into the switch on opcode - it handles shifts already.
if (BinOp && (BinOp->getOpcode() == Instruction::AShr ||
              BinOp->getOpcode() == Instruction::LShr)) {
  ConstantInt *CI = dyn_cast<ConstantInt>(BinOp->getOperand(1));
  if (CI && TLI->hasExtractBitsInsn())
    if (OptimizeExtractBits(BinOp, CI, *TLI, *DL))
      return true;
}

if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) {
  if (GEPI->hasAllZeroIndices()) {
    /// The GEP operand must be a pointer, so must its result -> BitCast
    Instruction *NC = new BitCastInst(GEPI->getOperand(0), GEPI->getType(),
                                      GEPI->getName(), GEPI);
    NC->setDebugLoc(GEPI->getDebugLoc());
    replaceAllUsesWith(GEPI, NC, FreshBBs, IsHugeFunc);
    GEPI->eraseFromParent();
    ++NumGEPsElim;
    optimizeInst(NC, ModifiedDT);
    return true;
  }
  if (tryUnmergingGEPsAcrossIndirectBr(GEPI, TTI)) {
    return true;
  }
  return false;
}

if (FreezeInst *FI = dyn_cast<FreezeInst>(I)) {
  // freeze(icmp a, const)) -> icmp (freeze a), const
  // This helps generate efficient conditional jumps.
  Instruction *CmpI = nullptr;
  if (ICmpInst *II = dyn_cast<ICmpInst>(FI->getOperand(0)))
    CmpI = II;
  else if (FCmpInst *F = dyn_cast<FCmpInst>(FI->getOperand(0)))
    CmpI = F->getFastMathFlags().none() ? F : nullptr;

  if (CmpI && CmpI->hasOneUse()) {
    auto Op0 = CmpI->getOperand(0), Op1 = CmpI->getOperand(1);
    bool Const0 = isa<ConstantInt>(Op0) || isa<ConstantFP>(Op0) ||
                  isa<ConstantPointerNull>(Op0);
    bool Const1 = isa<ConstantInt>(Op1) || isa<ConstantFP>(Op1) ||
                  isa<ConstantPointerNull>(Op1);
    if (Const0 || Const1) {
      if (!Const0 || !Const1) {
        auto *F = new FreezeInst(Const0 ? Op1 : Op0, "", CmpI);
        F->takeName(FI);
        CmpI->setOperand(Const0 ? 1 : 0, F);
      }
      replaceAllUsesWith(FI, CmpI, FreshBBs, IsHugeFunc);
      FI->eraseFromParent();
      return true;
    }
  }
  return false;
}

if (tryToSinkFreeOperands(I))
  return true;

switch (I->getOpcode()) {
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
  return optimizeShiftInst(cast<BinaryOperator>(I));
case Instruction::Call:
  return optimizeCallInst(cast<CallInst>(I), ModifiedDT);
case Instruction::Select:
  return optimizeSelectInst(cast<SelectInst>(I));
case Instruction::ShuffleVector:
  return optimizeShuffleVectorInst(cast<ShuffleVectorInst>(I));
case Instruction::Switch:
  return optimizeSwitchInst(cast<SwitchInst>(I));
case Instruction::ExtractElement:
  return optimizeExtractElementInst(cast<ExtractElementInst>(I));
case Instruction::Br:
  return optimizeBranch(cast<BranchInst>(I), *TLI, FreshBBs, IsHugeFunc);
}

return false;
8208}

8210/// Given an OR instruction, check to see if this is a bitreverse
8211/// idiom. If so, insert the new intrinsic and return true.
8212bool CodeGenPrepare::makeBitReverse(Instruction &I) {
if (!I.getType()->isIntegerTy() ||
    !TLI->isOperationLegalOrCustom(ISD::BITREVERSE,
                                   TLI->getValueType(*DL, I.getType(), true)))
  return false;

SmallVector<Instruction *, 4> Insts;
if (!recognizeBSwapOrBitReverseIdiom(&I, false, true, Insts))
  return false;
Instruction *LastInst = Insts.back();
replaceAllUsesWith(&I, LastInst, FreshBBs, IsHugeFunc);
RecursivelyDeleteTriviallyDeadInstructions(
    &I, TLInfo, nullptr,
    [&](Value *V) { removeAllAssertingVHReferences(V); });
return true;
8227}

8229// In this pass we look for GEP and cast instructions that are used
8230// across basic blocks and rewrite them to improve basic-block-at-a-time
8231// selection.
8232bool CodeGenPrepare::optimizeBlock(BasicBlock &BB, ModifyDT &ModifiedDT) {
SunkAddrs.clear();
bool MadeChange = false;

do {
  CurInstIterator = BB.begin();
  ModifiedDT = ModifyDT::NotModifyDT;
  while (CurInstIterator != BB.end()) {
    MadeChange |= optimizeInst(&*CurInstIterator++, ModifiedDT);
    if (ModifiedDT != ModifyDT::NotModifyDT) {
      // For huge function we tend to quickly go though the inner optmization
      // opportunities in the BB. So we go back to the BB head to re-optimize
      // each instruction instead of go back to the function head.
      if (IsHugeFunc) {
        DT.reset();
        getDT(*BB.getParent());
        break;
      } else {
        return true;
      }
    }
  }
} while (ModifiedDT == ModifyDT::ModifyInstDT);

bool MadeBitReverse = true;
while (MadeBitReverse) {
  MadeBitReverse = false;
  for (auto &I : reverse(BB)) {
    if (makeBitReverse(I)) {
      MadeBitReverse = MadeChange = true;
      break;
    }
  }
}
MadeChange |= dupRetToEnableTailCallOpts(&BB, ModifiedDT);

return MadeChange;
8269}

8271// Some CGP optimizations may move or alter what's computed in a block. Check
8272// whether a dbg.value intrinsic could be pointed at a more appropriate operand.
8273bool CodeGenPrepare::fixupDbgValue(Instruction *I) {
assert(isa<DbgValueInst>(I))(static_cast <bool> (isa<DbgValueInst>(I)) ? void
 (0) : __assert_fail ("isa<DbgValueInst>(I)", "llvm/lib/CodeGen/CodeGenPrepare.cpp"
, 8274, __extension__ __PRETTY_FUNCTION__));
DbgValueInst &DVI = *cast<DbgValueInst>(I);

// Does this dbg.value refer to a sunk address calculation?
bool AnyChange = false;
SmallDenseSet<Value *> LocationOps(DVI.location_ops().begin(),
                                   DVI.location_ops().end());
for (Value *Location : LocationOps) {
  WeakTrackingVH SunkAddrVH = SunkAddrs[Location];
  Value *SunkAddr = SunkAddrVH.pointsToAliveValue() ? SunkAddrVH : nullptr;
  if (SunkAddr) {
    // Point dbg.value at locally computed address, which should give the best
    // opportunity to be accurately lowered. This update may change the type
    // of pointer being referred to; however this makes no difference to
    // debugging information, and we can't generate bitcasts that may affect
    // codegen.
    DVI.replaceVariableLocationOp(Location, SunkAddr);
    AnyChange = true;
  }
}
return AnyChange;
8295}

8297// A llvm.dbg.value may be using a value before its definition, due to
8298// optimizations in this pass and others. Scan for such dbg.values, and rescue
8299// them by moving the dbg.value to immediately after the value definition.
8300// FIXME: Ideally this should never be necessary, and this has the potential
8301// to re-order dbg.value intrinsics.
8302bool CodeGenPrepare::placeDbgValues(Function &F) {
bool MadeChange = false;
DominatorTree DT(F);

for (BasicBlock &BB : F) {
  for (Instruction &Insn : llvm::make_early_inc_range(BB)) {
    DbgValueInst *DVI = dyn_cast<DbgValueInst>(&Insn);
    if (!DVI)
      continue;

    SmallVector<Instruction *, 4> VIs;
    for (Value *V : DVI->getValues())
      if (Instruction *VI = dyn_cast_or_null<Instruction>(V))
        VIs.push_back(VI);

    // This DVI may depend on multiple instructions, complicating any
    // potential sink. This block takes the defensive approach, opting to
    // "undef" the DVI if it has more than one instruction and any of them do
    // not dominate DVI.
    for (Instruction *VI : VIs) {
      if (VI->isTerminator())
        continue;

      // If VI is a phi in a block with an EHPad terminator, we can't insert
      // after it.
      if (isa<PHINode>(VI) && VI->getParent()->getTerminator()->isEHPad())
        continue;

      // If the defining instruction dominates the dbg.value, we do not need
      // to move the dbg.value.
      if (DT.dominates(VI, DVI))
        continue;

      // If we depend on multiple instructions and any of them doesn't
      // dominate this DVI, we probably can't salvage it: moving it to
      // after any of the instructions could cause us to lose the others.
      if (VIs.size() > 1) {
        LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Unable to find valid location for Debug Value, undefing:\n"
 << *DVI; } } while (false)
            dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Unable to find valid location for Debug Value, undefing:\n"
 << *DVI; } } while (false)
            << "Unable to find valid location for Debug Value, undefing:\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Unable to find valid location for Debug Value, undefing:\n"
 << *DVI; } } while (false)
            << *DVI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Unable to find valid location for Debug Value, undefing:\n"
 << *DVI; } } while (false);
        DVI->setKillLocation();
        break;
      }

      LLVM_DEBUG(dbgs() << "Moving Debug Value before :\n"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Moving Debug Value before :\n"
 << *DVI << ' ' << *VI; } } while (false)
                        << *DVI << ' ' << *VI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Moving Debug Value before :\n"
 << *DVI << ' ' << *VI; } } while (false);
      DVI->removeFromParent();
      if (isa<PHINode>(VI))
        DVI->insertBefore(&*VI->getParent()->getFirstInsertionPt());
      else
        DVI->insertAfter(VI);
      MadeChange = true;
      ++NumDbgValueMoved;
    }
  }
}
return MadeChange;
8360}

8362// Group scattered pseudo probes in a block to favor SelectionDAG. Scattered
8363// probes can be chained dependencies of other regular DAG nodes and block DAG
8364// combine optimizations.
8365bool CodeGenPrepare::placePseudoProbes(Function &F) {
bool MadeChange = false;
for (auto &Block : F) {
  // Move the rest probes to the beginning of the block.
  auto FirstInst = Block.getFirstInsertionPt();
  while (FirstInst != Block.end() && FirstInst->isDebugOrPseudoInst())
    ++FirstInst;
  BasicBlock::iterator I(FirstInst);
  I++;
  while (I != Block.end()) {
    if (auto *II = dyn_cast<PseudoProbeInst>(I++)) {
      II->moveBefore(&*FirstInst);
      MadeChange = true;
    }
  }
}
return MadeChange;
8382}

8384/// Scale down both weights to fit into uint32_t.
8385static void scaleWeights(uint64_t &NewTrue, uint64_t &NewFalse) {
uint64_t NewMax = (NewTrue > NewFalse) ? NewTrue : NewFalse;
uint32_t Scale = (NewMax / std::numeric_limits<uint32_t>::max()) + 1;
NewTrue = NewTrue / Scale;
NewFalse = NewFalse / Scale;
8390}

8392/// Some targets prefer to split a conditional branch like:
8393/// \code
8394///   %0 = icmp ne i32 %a, 0
8395///   %1 = icmp ne i32 %b, 0
8396///   %or.cond = or i1 %0, %1
8397///   br i1 %or.cond, label %TrueBB, label %FalseBB
8398/// \endcode
8399/// into multiple branch instructions like:
8400/// \code
8401///   bb1:
8402///     %0 = icmp ne i32 %a, 0
8403///     br i1 %0, label %TrueBB, label %bb2
8404///   bb2:
8405///     %1 = icmp ne i32 %b, 0
8406///     br i1 %1, label %TrueBB, label %FalseBB
8407/// \endcode
8408/// This usually allows instruction selection to do even further optimizations
8409/// and combine the compare with the branch instruction. Currently this is
8410/// applied for targets which have "cheap" jump instructions.
8411///
8412/// FIXME: Remove the (equivalent?) implementation in SelectionDAG.
8413///
8414bool CodeGenPrepare::splitBranchCondition(Function &F, ModifyDT &ModifiedDT) {
if (!TM->Options.EnableFastISel || TLI->isJumpExpensive())
  return false;

bool MadeChange = false;
for (auto &BB : F) {
  // Does this BB end with the following?
  //   %cond1 = icmp|fcmp|binary instruction ...
  //   %cond2 = icmp|fcmp|binary instruction ...
  //   %cond.or = or|and i1 %cond1, cond2
  //   br i1 %cond.or label %dest1, label %dest2"
  Instruction *LogicOp;
  BasicBlock *TBB, *FBB;
  if (!match(BB.getTerminator(),
             m_Br(m_OneUse(m_Instruction(LogicOp)), TBB, FBB)))
    continue;

  auto *Br1 = cast<BranchInst>(BB.getTerminator());
  if (Br1->getMetadata(LLVMContext::MD_unpredictable))
    continue;

  // The merging of mostly empty BB can cause a degenerate branch.
  if (TBB == FBB)
    continue;

  unsigned Opc;
  Value *Cond1, *Cond2;
  if (match(LogicOp,
            m_LogicalAnd(m_OneUse(m_Value(Cond1)), m_OneUse(m_Value(Cond2)))))
    Opc = Instruction::And;
  else if (match(LogicOp, m_LogicalOr(m_OneUse(m_Value(Cond1)),
                                      m_OneUse(m_Value(Cond2)))))
    Opc = Instruction::Or;
  else
    continue;

  auto IsGoodCond = [](Value *Cond) {
    return match(
        Cond,
        m_CombineOr(m_Cmp(), m_CombineOr(m_LogicalAnd(m_Value(), m_Value()),
                                         m_LogicalOr(m_Value(), m_Value()))));
  };
  if (!IsGoodCond(Cond1) || !IsGoodCond(Cond2))
    continue;

  LLVM_DEBUG(dbgs() << "Before branch condition splitting\n"; BB.dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "Before branch condition splitting\n"
; BB.dump(); } } while (false);

  // Create a new BB.
  auto *TmpBB =
      BasicBlock::Create(BB.getContext(), BB.getName() + ".cond.split",
                         BB.getParent(), BB.getNextNode());
  if (IsHugeFunc)
    FreshBBs.insert(TmpBB);

  // Update original basic block by using the first condition directly by the
  // branch instruction and removing the no longer needed and/or instruction.
  Br1->setCondition(Cond1);
  LogicOp->eraseFromParent();

  // Depending on the condition we have to either replace the true or the
  // false successor of the original branch instruction.
  if (Opc == Instruction::And)
    Br1->setSuccessor(0, TmpBB);
  else
    Br1->setSuccessor(1, TmpBB);

  // Fill in the new basic block.
  auto *Br2 = IRBuilder<>(TmpBB).CreateCondBr(Cond2, TBB, FBB);
  if (auto *I = dyn_cast<Instruction>(Cond2)) {
    I->removeFromParent();
    I->insertBefore(Br2);
  }

  // Update PHI nodes in both successors. The original BB needs to be
  // replaced in one successor's PHI nodes, because the branch comes now from
  // the newly generated BB (NewBB). In the other successor we need to add one
  // incoming edge to the PHI nodes, because both branch instructions target
  // now the same successor. Depending on the original branch condition
  // (and/or) we have to swap the successors (TrueDest, FalseDest), so that
  // we perform the correct update for the PHI nodes.
  // This doesn't change the successor order of the just created branch
  // instruction (or any other instruction).
  if (Opc == Instruction::Or)
    std::swap(TBB, FBB);

  // Replace the old BB with the new BB.
  TBB->replacePhiUsesWith(&BB, TmpBB);

  // Add another incoming edge from the new BB.
  for (PHINode &PN : FBB->phis()) {
    auto *Val = PN.getIncomingValueForBlock(&BB);
    PN.addIncoming(Val, TmpBB);
  }

  // Update the branch weights (from SelectionDAGBuilder::
  // FindMergedConditions).
  if (Opc == Instruction::Or) {
    // Codegen X | Y as:
    // BB1:
    //   jmp_if_X TBB
    //   jmp TmpBB
    // TmpBB:
    //   jmp_if_Y TBB
    //   jmp FBB
    //

    // We have flexibility in setting Prob for BB1 and Prob for NewBB.
    // The requirement is that
    //   TrueProb for BB1 + (FalseProb for BB1 * TrueProb for TmpBB)
    //     = TrueProb for original BB.
    // Assuming the original weights are A and B, one choice is to set BB1's
    // weights to A and A+2B, and set TmpBB's weights to A and 2B. This choice
    // assumes that
    //   TrueProb for BB1 == FalseProb for BB1 * TrueProb for TmpBB.
    // Another choice is to assume TrueProb for BB1 equals to TrueProb for
    // TmpBB, but the math is more complicated.
    uint64_t TrueWeight, FalseWeight;
    if (extractBranchWeights(*Br1, TrueWeight, FalseWeight)) {
      uint64_t NewTrueWeight = TrueWeight;
      uint64_t NewFalseWeight = TrueWeight + 2 * FalseWeight;
      scaleWeights(NewTrueWeight, NewFalseWeight);
      Br1->setMetadata(LLVMContext::MD_prof,
                       MDBuilder(Br1->getContext())
                           .createBranchWeights(TrueWeight, FalseWeight));

      NewTrueWeight = TrueWeight;
      NewFalseWeight = 2 * FalseWeight;
      scaleWeights(NewTrueWeight, NewFalseWeight);
      Br2->setMetadata(LLVMContext::MD_prof,
                       MDBuilder(Br2->getContext())
                           .createBranchWeights(TrueWeight, FalseWeight));
    }
  } else {
    // Codegen X & Y as:
    // BB1:
    //   jmp_if_X TmpBB
    //   jmp FBB
    // TmpBB:
    //   jmp_if_Y TBB
    //   jmp FBB
    //
    //  This requires creation of TmpBB after CurBB.

    // We have flexibility in setting Prob for BB1 and Prob for TmpBB.
    // The requirement is that
    //   FalseProb for BB1 + (TrueProb for BB1 * FalseProb for TmpBB)
    //     = FalseProb for original BB.
    // Assuming the original weights are A and B, one choice is to set BB1's
    // weights to 2A+B and B, and set TmpBB's weights to 2A and B. This choice
    // assumes that
    //   FalseProb for BB1 == TrueProb for BB1 * FalseProb for TmpBB.
    uint64_t TrueWeight, FalseWeight;
    if (extractBranchWeights(*Br1, TrueWeight, FalseWeight)) {
      uint64_t NewTrueWeight = 2 * TrueWeight + FalseWeight;
      uint64_t NewFalseWeight = FalseWeight;
      scaleWeights(NewTrueWeight, NewFalseWeight);
      Br1->setMetadata(LLVMContext::MD_prof,
                       MDBuilder(Br1->getContext())
                           .createBranchWeights(TrueWeight, FalseWeight));

      NewTrueWeight = 2 * TrueWeight;
      NewFalseWeight = FalseWeight;
      scaleWeights(NewTrueWeight, NewFalseWeight);
      Br2->setMetadata(LLVMContext::MD_prof,
                       MDBuilder(Br2->getContext())
                           .createBranchWeights(TrueWeight, FalseWeight));
    }
  }

  ModifiedDT = ModifyDT::ModifyBBDT;
  MadeChange = true;

  LLVM_DEBUG(dbgs() << "After branch condition splitting\n"; BB.dump();do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "After branch condition splitting\n"
; BB.dump(); TmpBB->dump(); } } while (false)
             TmpBB->dump())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("codegenprepare")) { dbgs() << "After branch condition splitting\n"
; BB.dump(); TmpBB->dump(); } } while (false);
}
return MadeChange;
8590}