1 files changed, 0 insertions, 2238 deletions

diff --git a/contrib/llvm/lib/CodeGen/IfConversion.cpp b/contrib/llvm/lib/CodeGen/IfConversion.cpp
deleted file mode 100644
index af556e2c856e..000000000000
--- a/contrib/llvm/lib/CodeGen/IfConversion.cpp
+++ /dev/null
@@ -1,2238 +0,0 @@
-//===- IfConversion.cpp - Machine code if conversion pass -----------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements the machine instruction level if-conversion pass, which
-// tries to convert conditional branches into predicated instructions.
-//
-//===----------------------------------------------------------------------===//
-
-#include "BranchFolding.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/ScopeExit.h"
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/SparseSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/iterator_range.h"
-#include "llvm/CodeGen/LivePhysRegs.h"
-#include "llvm/CodeGen/MachineBasicBlock.h"
-#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
-#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
-#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineInstr.h"
-#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/CodeGen/MachineModuleInfo.h"
-#include "llvm/CodeGen/MachineOperand.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/CodeGen/TargetInstrInfo.h"
-#include "llvm/CodeGen/TargetLowering.h"
-#include "llvm/CodeGen/TargetRegisterInfo.h"
-#include "llvm/CodeGen/TargetSchedule.h"
-#include "llvm/CodeGen/TargetSubtargetInfo.h"
-#include "llvm/IR/DebugLoc.h"
-#include "llvm/MC/MCRegisterInfo.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/BranchProbability.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/raw_ostream.h"
-#include <algorithm>
-#include <cassert>
-#include <functional>
-#include <iterator>
-#include <memory>
-#include <utility>
-#include <vector>
-
-using namespace llvm;
-
-#define DEBUG_TYPE "if-converter"
-
-// Hidden options for help debugging.
-static cl::opt<int> IfCvtFnStart("ifcvt-fn-start", cl::init(-1), cl::Hidden);
-static cl::opt<int> IfCvtFnStop("ifcvt-fn-stop", cl::init(-1), cl::Hidden);
-static cl::opt<int> IfCvtLimit("ifcvt-limit", cl::init(-1), cl::Hidden);
-static cl::opt<bool> DisableSimple("disable-ifcvt-simple",
-                                   cl::init(false), cl::Hidden);
-static cl::opt<bool> DisableSimpleF("disable-ifcvt-simple-false",
-                                    cl::init(false), cl::Hidden);
-static cl::opt<bool> DisableTriangle("disable-ifcvt-triangle",
-                                     cl::init(false), cl::Hidden);
-static cl::opt<bool> DisableTriangleR("disable-ifcvt-triangle-rev",
-                                      cl::init(false), cl::Hidden);
-static cl::opt<bool> DisableTriangleF("disable-ifcvt-triangle-false",
-                                      cl::init(false), cl::Hidden);
-static cl::opt<bool> DisableTriangleFR("disable-ifcvt-triangle-false-rev",
-                                       cl::init(false), cl::Hidden);
-static cl::opt<bool> DisableDiamond("disable-ifcvt-diamond",
-                                    cl::init(false), cl::Hidden);
-static cl::opt<bool> DisableForkedDiamond("disable-ifcvt-forked-diamond",
-                                        cl::init(false), cl::Hidden);
-static cl::opt<bool> IfCvtBranchFold("ifcvt-branch-fold",
-                                     cl::init(true), cl::Hidden);
-
-STATISTIC(NumSimple,       "Number of simple if-conversions performed");
-STATISTIC(NumSimpleFalse,  "Number of simple (F) if-conversions performed");
-STATISTIC(NumTriangle,     "Number of triangle if-conversions performed");
-STATISTIC(NumTriangleRev,  "Number of triangle (R) if-conversions performed");
-STATISTIC(NumTriangleFalse,"Number of triangle (F) if-conversions performed");
-STATISTIC(NumTriangleFRev, "Number of triangle (F/R) if-conversions performed");
-STATISTIC(NumDiamonds,     "Number of diamond if-conversions performed");
-STATISTIC(NumForkedDiamonds, "Number of forked-diamond if-conversions performed");
-STATISTIC(NumIfConvBBs,    "Number of if-converted blocks");
-STATISTIC(NumDupBBs,       "Number of duplicated blocks");
-STATISTIC(NumUnpred,       "Number of true blocks of diamonds unpredicated");
-
-namespace {
-
-  class IfConverter : public MachineFunctionPass {
-    enum IfcvtKind {
-      ICNotClassfied,  // BB data valid, but not classified.
-      ICSimpleFalse,   // Same as ICSimple, but on the false path.
-      ICSimple,        // BB is entry of an one split, no rejoin sub-CFG.
-      ICTriangleFRev,  // Same as ICTriangleFalse, but false path rev condition.
-      ICTriangleRev,   // Same as ICTriangle, but true path rev condition.
-      ICTriangleFalse, // Same as ICTriangle, but on the false path.
-      ICTriangle,      // BB is entry of a triangle sub-CFG.
-      ICDiamond,       // BB is entry of a diamond sub-CFG.
-      ICForkedDiamond  // BB is entry of an almost diamond sub-CFG, with a
-                       // common tail that can be shared.
-    };
-
-    /// One per MachineBasicBlock, this is used to cache the result
-    /// if-conversion feasibility analysis. This includes results from
-    /// TargetInstrInfo::analyzeBranch() (i.e. TBB, FBB, and Cond), and its
-    /// classification, and common tail block of its successors (if it's a
-    /// diamond shape), its size, whether it's predicable, and whether any
-    /// instruction can clobber the 'would-be' predicate.
-    ///
-    /// IsDone          - True if BB is not to be considered for ifcvt.
-    /// IsBeingAnalyzed - True if BB is currently being analyzed.
-    /// IsAnalyzed      - True if BB has been analyzed (info is still valid).
-    /// IsEnqueued      - True if BB has been enqueued to be ifcvt'ed.
-    /// IsBrAnalyzable  - True if analyzeBranch() returns false.
-    /// HasFallThrough  - True if BB may fallthrough to the following BB.
-    /// IsUnpredicable  - True if BB is known to be unpredicable.
-    /// ClobbersPred    - True if BB could modify predicates (e.g. has
-    ///                   cmp, call, etc.)
-    /// NonPredSize     - Number of non-predicated instructions.
-    /// ExtraCost       - Extra cost for multi-cycle instructions.
-    /// ExtraCost2      - Some instructions are slower when predicated
-    /// BB              - Corresponding MachineBasicBlock.
-    /// TrueBB / FalseBB- See analyzeBranch().
-    /// BrCond          - Conditions for end of block conditional branches.
-    /// Predicate       - Predicate used in the BB.
-    struct BBInfo {
-      bool IsDone          : 1;
-      bool IsBeingAnalyzed : 1;
-      bool IsAnalyzed      : 1;
-      bool IsEnqueued      : 1;
-      bool IsBrAnalyzable  : 1;
-      bool IsBrReversible  : 1;
-      bool HasFallThrough  : 1;
-      bool IsUnpredicable  : 1;
-      bool CannotBeCopied  : 1;
-      bool ClobbersPred    : 1;
-      unsigned NonPredSize = 0;
-      unsigned ExtraCost = 0;
-      unsigned ExtraCost2 = 0;
-      MachineBasicBlock *BB = nullptr;
-      MachineBasicBlock *TrueBB = nullptr;
-      MachineBasicBlock *FalseBB = nullptr;
-      SmallVector<MachineOperand, 4> BrCond;
-      SmallVector<MachineOperand, 4> Predicate;
-
-      BBInfo() : IsDone(false), IsBeingAnalyzed(false),
-                 IsAnalyzed(false), IsEnqueued(false), IsBrAnalyzable(false),
-                 IsBrReversible(false), HasFallThrough(false),
-                 IsUnpredicable(false), CannotBeCopied(false),
-                 ClobbersPred(false) {}
-    };
-
-    /// Record information about pending if-conversions to attempt:
-    /// BBI             - Corresponding BBInfo.
-    /// Kind            - Type of block. See IfcvtKind.
-    /// NeedSubsumption - True if the to-be-predicated BB has already been
-    ///                   predicated.
-    /// NumDups      - Number of instructions that would be duplicated due
-    ///                   to this if-conversion. (For diamonds, the number of
-    ///                   identical instructions at the beginnings of both
-    ///                   paths).
-    /// NumDups2     - For diamonds, the number of identical instructions
-    ///                   at the ends of both paths.
-    struct IfcvtToken {
-      BBInfo &BBI;
-      IfcvtKind Kind;
-      unsigned NumDups;
-      unsigned NumDups2;
-      bool NeedSubsumption : 1;
-      bool TClobbersPred : 1;
-      bool FClobbersPred : 1;
-
-      IfcvtToken(BBInfo &b, IfcvtKind k, bool s, unsigned d, unsigned d2 = 0,
-                 bool tc = false, bool fc = false)
-        : BBI(b), Kind(k), NumDups(d), NumDups2(d2), NeedSubsumption(s),
-          TClobbersPred(tc), FClobbersPred(fc) {}
-    };
-
-    /// Results of if-conversion feasibility analysis indexed by basic block
-    /// number.
-    std::vector<BBInfo> BBAnalysis;
-    TargetSchedModel SchedModel;
-
-    const TargetLoweringBase *TLI;
-    const TargetInstrInfo *TII;
-    const TargetRegisterInfo *TRI;
-    const MachineBranchProbabilityInfo *MBPI;
-    MachineRegisterInfo *MRI;
-
-    LivePhysRegs Redefs;
-
-    bool PreRegAlloc;
-    bool MadeChange;
-    int FnNum = -1;
-    std::function<bool(const MachineFunction &)> PredicateFtor;
-
-  public:
-    static char ID;
-
-    IfConverter(std::function<bool(const MachineFunction &)> Ftor = nullptr)
-        : MachineFunctionPass(ID), PredicateFtor(std::move(Ftor)) {
-      initializeIfConverterPass(*PassRegistry::getPassRegistry());
-    }
-
-    void getAnalysisUsage(AnalysisUsage &AU) const override {
-      AU.addRequired<MachineBlockFrequencyInfo>();
-      AU.addRequired<MachineBranchProbabilityInfo>();
-      MachineFunctionPass::getAnalysisUsage(AU);
-    }
-
-    bool runOnMachineFunction(MachineFunction &MF) override;
-
-    MachineFunctionProperties getRequiredProperties() const override {
-      return MachineFunctionProperties().set(
-          MachineFunctionProperties::Property::NoVRegs);
-    }
-
-  private:
-    bool reverseBranchCondition(BBInfo &BBI) const;
-    bool ValidSimple(BBInfo &TrueBBI, unsigned &Dups,
-                     BranchProbability Prediction) const;
-    bool ValidTriangle(BBInfo &TrueBBI, BBInfo &FalseBBI,
-                       bool FalseBranch, unsigned &Dups,
-                       BranchProbability Prediction) const;
-    bool CountDuplicatedInstructions(
-        MachineBasicBlock::iterator &TIB, MachineBasicBlock::iterator &FIB,
-        MachineBasicBlock::iterator &TIE, MachineBasicBlock::iterator &FIE,
-        unsigned &Dups1, unsigned &Dups2,
-        MachineBasicBlock &TBB, MachineBasicBlock &FBB,
-        bool SkipUnconditionalBranches) const;
-    bool ValidDiamond(BBInfo &TrueBBI, BBInfo &FalseBBI,
-                      unsigned &Dups1, unsigned &Dups2,
-                      BBInfo &TrueBBICalc, BBInfo &FalseBBICalc) const;
-    bool ValidForkedDiamond(BBInfo &TrueBBI, BBInfo &FalseBBI,
-                            unsigned &Dups1, unsigned &Dups2,
-                            BBInfo &TrueBBICalc, BBInfo &FalseBBICalc) const;
-    void AnalyzeBranches(BBInfo &BBI);
-    void ScanInstructions(BBInfo &BBI,
-                          MachineBasicBlock::iterator &Begin,
-                          MachineBasicBlock::iterator &End,
-                          bool BranchUnpredicable = false) const;
-    bool RescanInstructions(
-        MachineBasicBlock::iterator &TIB, MachineBasicBlock::iterator &FIB,
-        MachineBasicBlock::iterator &TIE, MachineBasicBlock::iterator &FIE,
-        BBInfo &TrueBBI, BBInfo &FalseBBI) const;
-    void AnalyzeBlock(MachineBasicBlock &MBB,
-                      std::vector<std::unique_ptr<IfcvtToken>> &Tokens);
-    bool FeasibilityAnalysis(BBInfo &BBI, SmallVectorImpl<MachineOperand> &Pred,
-                             bool isTriangle = false, bool RevBranch = false,
-                             bool hasCommonTail = false);
-    void AnalyzeBlocks(MachineFunction &MF,
-                       std::vector<std::unique_ptr<IfcvtToken>> &Tokens);
-    void InvalidatePreds(MachineBasicBlock &MBB);
-    bool IfConvertSimple(BBInfo &BBI, IfcvtKind Kind);
-    bool IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind);
-    bool IfConvertDiamondCommon(BBInfo &BBI, BBInfo &TrueBBI, BBInfo &FalseBBI,
-                                unsigned NumDups1, unsigned NumDups2,
-                                bool TClobbersPred, bool FClobbersPred,
-                                bool RemoveBranch, bool MergeAddEdges);
-    bool IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind,
-                          unsigned NumDups1, unsigned NumDups2,
-                          bool TClobbers, bool FClobbers);
-    bool IfConvertForkedDiamond(BBInfo &BBI, IfcvtKind Kind,
-                              unsigned NumDups1, unsigned NumDups2,
-                              bool TClobbers, bool FClobbers);
-    void PredicateBlock(BBInfo &BBI,
-                        MachineBasicBlock::iterator E,
-                        SmallVectorImpl<MachineOperand> &Cond,
-                        SmallSet<MCPhysReg, 4> *LaterRedefs = nullptr);
-    void CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI,
-                               SmallVectorImpl<MachineOperand> &Cond,
-                               bool IgnoreBr = false);
-    void MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges = true);
-
-    bool MeetIfcvtSizeLimit(MachineBasicBlock &BB,
-                            unsigned Cycle, unsigned Extra,
-                            BranchProbability Prediction) const {
-      return Cycle > 0 && TII->isProfitableToIfCvt(BB, Cycle, Extra,
-                                                   Prediction);
-    }
-
-    bool MeetIfcvtSizeLimit(MachineBasicBlock &TBB,
-                            unsigned TCycle, unsigned TExtra,
-                            MachineBasicBlock &FBB,
-                            unsigned FCycle, unsigned FExtra,
-                            BranchProbability Prediction) const {
-      return TCycle > 0 && FCycle > 0 &&
-        TII->isProfitableToIfCvt(TBB, TCycle, TExtra, FBB, FCycle, FExtra,
-                                 Prediction);
-    }
-
-    /// Returns true if Block ends without a terminator.
-    bool blockAlwaysFallThrough(BBInfo &BBI) const {
-      return BBI.IsBrAnalyzable && BBI.TrueBB == nullptr;
-    }
-
-    /// Used to sort if-conversion candidates.
-    static bool IfcvtTokenCmp(const std::unique_ptr<IfcvtToken> &C1,
-                              const std::unique_ptr<IfcvtToken> &C2) {
-      int Incr1 = (C1->Kind == ICDiamond)
-        ? -(int)(C1->NumDups + C1->NumDups2) : (int)C1->NumDups;
-      int Incr2 = (C2->Kind == ICDiamond)
-        ? -(int)(C2->NumDups + C2->NumDups2) : (int)C2->NumDups;
-      if (Incr1 > Incr2)
-        return true;
-      else if (Incr1 == Incr2) {
-        // Favors subsumption.
-        if (!C1->NeedSubsumption && C2->NeedSubsumption)
-          return true;
-        else if (C1->NeedSubsumption == C2->NeedSubsumption) {
-          // Favors diamond over triangle, etc.
-          if ((unsigned)C1->Kind < (unsigned)C2->Kind)
-            return true;
-          else if (C1->Kind == C2->Kind)
-            return C1->BBI.BB->getNumber() < C2->BBI.BB->getNumber();
-        }
-      }
-      return false;
-    }
-  };
-
-} // end anonymous namespace
-
-char IfConverter::ID = 0;
-
-char &llvm::IfConverterID = IfConverter::ID;
-
-INITIALIZE_PASS_BEGIN(IfConverter, DEBUG_TYPE, "If Converter", false, false)
-INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
-INITIALIZE_PASS_END(IfConverter, DEBUG_TYPE, "If Converter", false, false)
-
-bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
-  if (skipFunction(MF.getFunction()) || (PredicateFtor && !PredicateFtor(MF)))
-    return false;
-
-  const TargetSubtargetInfo &ST = MF.getSubtarget();
-  TLI = ST.getTargetLowering();
-  TII = ST.getInstrInfo();
-  TRI = ST.getRegisterInfo();
-  BranchFolder::MBFIWrapper MBFI(getAnalysis<MachineBlockFrequencyInfo>());
-  MBPI = &getAnalysis<MachineBranchProbabilityInfo>();
-  MRI = &MF.getRegInfo();
-  SchedModel.init(&ST);
-
-  if (!TII) return false;
-
-  PreRegAlloc = MRI->isSSA();
-
-  bool BFChange = false;
-  if (!PreRegAlloc) {
-    // Tail merge tend to expose more if-conversion opportunities.
-    BranchFolder BF(true, false, MBFI, *MBPI);
-    BFChange = BF.OptimizeFunction(MF, TII, ST.getRegisterInfo(),
-                                   getAnalysisIfAvailable<MachineModuleInfo>());
-  }
-
-  LLVM_DEBUG(dbgs() << "\nIfcvt: function (" << ++FnNum << ") \'"
-                    << MF.getName() << "\'");
-
-  if (FnNum < IfCvtFnStart || (IfCvtFnStop != -1 && FnNum > IfCvtFnStop)) {
-    LLVM_DEBUG(dbgs() << " skipped\n");
-    return false;
-  }
-  LLVM_DEBUG(dbgs() << "\n");
-
-  MF.RenumberBlocks();
-  BBAnalysis.resize(MF.getNumBlockIDs());
-
-  std::vector<std::unique_ptr<IfcvtToken>> Tokens;
-  MadeChange = false;
-  unsigned NumIfCvts = NumSimple + NumSimpleFalse + NumTriangle +
-    NumTriangleRev + NumTriangleFalse + NumTriangleFRev + NumDiamonds;
-  while (IfCvtLimit == -1 || (int)NumIfCvts < IfCvtLimit) {
-    // Do an initial analysis for each basic block and find all the potential
-    // candidates to perform if-conversion.
-    bool Change = false;
-    AnalyzeBlocks(MF, Tokens);
-    while (!Tokens.empty()) {
-      std::unique_ptr<IfcvtToken> Token = std::move(Tokens.back());
-      Tokens.pop_back();
-      BBInfo &BBI = Token->BBI;
-      IfcvtKind Kind = Token->Kind;
-      unsigned NumDups = Token->NumDups;
-      unsigned NumDups2 = Token->NumDups2;
-
-      // If the block has been evicted out of the queue or it has already been
-      // marked dead (due to it being predicated), then skip it.
-      if (BBI.IsDone)
-        BBI.IsEnqueued = false;
-      if (!BBI.IsEnqueued)
-        continue;
-
-      BBI.IsEnqueued = false;
-
-      bool RetVal = false;
-      switch (Kind) {
-      default: llvm_unreachable("Unexpected!");
-      case ICSimple:
-      case ICSimpleFalse: {
-        bool isFalse = Kind == ICSimpleFalse;
-        if ((isFalse && DisableSimpleF) || (!isFalse && DisableSimple)) break;
-        LLVM_DEBUG(dbgs() << "Ifcvt (Simple"
-                          << (Kind == ICSimpleFalse ? " false" : "")
-                          << "): " << printMBBReference(*BBI.BB) << " ("
-                          << ((Kind == ICSimpleFalse) ? BBI.FalseBB->getNumber()
-                                                      : BBI.TrueBB->getNumber())
-                          << ") ");
-        RetVal = IfConvertSimple(BBI, Kind);
-        LLVM_DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
-        if (RetVal) {
-          if (isFalse) ++NumSimpleFalse;
-          else         ++NumSimple;
-        }
-       break;
-      }
-      case ICTriangle:
-      case ICTriangleRev:
-      case ICTriangleFalse:
-      case ICTriangleFRev: {
-        bool isFalse = Kind == ICTriangleFalse;
-        bool isRev   = (Kind == ICTriangleRev || Kind == ICTriangleFRev);
-        if (DisableTriangle && !isFalse && !isRev) break;
-        if (DisableTriangleR && !isFalse && isRev) break;
-        if (DisableTriangleF && isFalse && !isRev) break;
-        if (DisableTriangleFR && isFalse && isRev) break;
-        LLVM_DEBUG(dbgs() << "Ifcvt (Triangle");
-        if (isFalse)
-          LLVM_DEBUG(dbgs() << " false");
-        if (isRev)
-          LLVM_DEBUG(dbgs() << " rev");
-        LLVM_DEBUG(dbgs() << "): " << printMBBReference(*BBI.BB)
-                          << " (T:" << BBI.TrueBB->getNumber()
-                          << ",F:" << BBI.FalseBB->getNumber() << ") ");
-        RetVal = IfConvertTriangle(BBI, Kind);
-        LLVM_DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
-        if (RetVal) {
-          if (isFalse) {
-            if (isRev) ++NumTriangleFRev;
-            else       ++NumTriangleFalse;
-          } else {
-            if (isRev) ++NumTriangleRev;
-            else       ++NumTriangle;
-          }
-        }
-        break;
-      }
-      case ICDiamond:
-        if (DisableDiamond) break;
-        LLVM_DEBUG(dbgs() << "Ifcvt (Diamond): " << printMBBReference(*BBI.BB)
-                          << " (T:" << BBI.TrueBB->getNumber()
-                          << ",F:" << BBI.FalseBB->getNumber() << ") ");
-        RetVal = IfConvertDiamond(BBI, Kind, NumDups, NumDups2,
-                                  Token->TClobbersPred,
-                                  Token->FClobbersPred);
-        LLVM_DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
-        if (RetVal) ++NumDiamonds;
-        break;
-      case ICForkedDiamond:
-        if (DisableForkedDiamond) break;
-        LLVM_DEBUG(dbgs() << "Ifcvt (Forked Diamond): "
-                          << printMBBReference(*BBI.BB)
-                          << " (T:" << BBI.TrueBB->getNumber()
-                          << ",F:" << BBI.FalseBB->getNumber() << ") ");
-        RetVal = IfConvertForkedDiamond(BBI, Kind, NumDups, NumDups2,
-                                      Token->TClobbersPred,
-                                      Token->FClobbersPred);
-        LLVM_DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
-        if (RetVal) ++NumForkedDiamonds;
-        break;
-      }
-
-      if (RetVal && MRI->tracksLiveness())
-        recomputeLivenessFlags(*BBI.BB);
-
-      Change |= RetVal;
-
-      NumIfCvts = NumSimple + NumSimpleFalse + NumTriangle + NumTriangleRev +
-        NumTriangleFalse + NumTriangleFRev + NumDiamonds;
-      if (IfCvtLimit != -1 && (int)NumIfCvts >= IfCvtLimit)
-        break;
-    }
-
-    if (!Change)
-      break;
-    MadeChange |= Change;
-  }
-
-  Tokens.clear();
-  BBAnalysis.clear();
-
-  if (MadeChange && IfCvtBranchFold) {
-    BranchFolder BF(false, false, MBFI, *MBPI);
-    BF.OptimizeFunction(MF, TII, MF.getSubtarget().getRegisterInfo(),
-                        getAnalysisIfAvailable<MachineModuleInfo>());
-  }
-
-  MadeChange |= BFChange;
-  return MadeChange;
-}
-
-/// BB has a fallthrough. Find its 'false' successor given its 'true' successor.
-static MachineBasicBlock *findFalseBlock(MachineBasicBlock *BB,
-                                         MachineBasicBlock *TrueBB) {
-  for (MachineBasicBlock *SuccBB : BB->successors()) {
-    if (SuccBB != TrueBB)
-      return SuccBB;
-  }
-  return nullptr;
-}
-
-/// Reverse the condition of the end of the block branch. Swap block's 'true'
-/// and 'false' successors.
-bool IfConverter::reverseBranchCondition(BBInfo &BBI) const {
-  DebugLoc dl;  // FIXME: this is nowhere
-  if (!TII->reverseBranchCondition(BBI.BrCond)) {
-    TII->removeBranch(*BBI.BB);
-    TII->insertBranch(*BBI.BB, BBI.FalseBB, BBI.TrueBB, BBI.BrCond, dl);
-    std::swap(BBI.TrueBB, BBI.FalseBB);
-    return true;
-  }
-  return false;
-}
-
-/// Returns the next block in the function blocks ordering. If it is the end,
-/// returns NULL.
-static inline MachineBasicBlock *getNextBlock(MachineBasicBlock &MBB) {
-  MachineFunction::iterator I = MBB.getIterator();
-  MachineFunction::iterator E = MBB.getParent()->end();
-  if (++I == E)
-    return nullptr;
-  return &*I;
-}
-
-/// Returns true if the 'true' block (along with its predecessor) forms a valid
-/// simple shape for ifcvt. It also returns the number of instructions that the
-/// ifcvt would need to duplicate if performed in Dups.
-bool IfConverter::ValidSimple(BBInfo &TrueBBI, unsigned &Dups,
-                              BranchProbability Prediction) const {
-  Dups = 0;
-  if (TrueBBI.IsBeingAnalyzed || TrueBBI.IsDone)
-    return false;
-
-  if (TrueBBI.IsBrAnalyzable)
-    return false;
-
-  if (TrueBBI.BB->pred_size() > 1) {
-    if (TrueBBI.CannotBeCopied ||
-        !TII->isProfitableToDupForIfCvt(*TrueBBI.BB, TrueBBI.NonPredSize,
-                                        Prediction))
-      return false;
-    Dups = TrueBBI.NonPredSize;
-  }
-
-  return true;
-}
-
-/// Returns true if the 'true' and 'false' blocks (along with their common
-/// predecessor) forms a valid triangle shape for ifcvt. If 'FalseBranch' is
-/// true, it checks if 'true' block's false branch branches to the 'false' block
-/// rather than the other way around. It also returns the number of instructions
-/// that the ifcvt would need to duplicate if performed in 'Dups'.
-bool IfConverter::ValidTriangle(BBInfo &TrueBBI, BBInfo &FalseBBI,
-                                bool FalseBranch, unsigned &Dups,
-                                BranchProbability Prediction) const {
-  Dups = 0;
-  if (TrueBBI.IsBeingAnalyzed || TrueBBI.IsDone)
-    return false;
-
-  if (TrueBBI.BB->pred_size() > 1) {
-    if (TrueBBI.CannotBeCopied)
-      return false;
-
-    unsigned Size = TrueBBI.NonPredSize;
-    if (TrueBBI.IsBrAnalyzable) {
-      if (TrueBBI.TrueBB && TrueBBI.BrCond.empty())
-        // Ends with an unconditional branch. It will be removed.
-        --Size;
-      else {
-        MachineBasicBlock *FExit = FalseBranch
-          ? TrueBBI.TrueBB : TrueBBI.FalseBB;
-        if (FExit)
-          // Require a conditional branch
-          ++Size;
-      }
-    }
-    if (!TII->isProfitableToDupForIfCvt(*TrueBBI.BB, Size, Prediction))
-      return false;
-    Dups = Size;
-  }
-
-  MachineBasicBlock *TExit = FalseBranch ? TrueBBI.FalseBB : TrueBBI.TrueBB;
-  if (!TExit && blockAlwaysFallThrough(TrueBBI)) {
-    MachineFunction::iterator I = TrueBBI.BB->getIterator();
-    if (++I == TrueBBI.BB->getParent()->end())
-      return false;
-    TExit = &*I;
-  }
-  return TExit && TExit == FalseBBI.BB;
-}
-
-/// Count duplicated instructions and move the iterators to show where they
-/// are.
-/// @param TIB True Iterator Begin
-/// @param FIB False Iterator Begin
-/// These two iterators initially point to the first instruction of the two
-/// blocks, and finally point to the first non-shared instruction.
-/// @param TIE True Iterator End
-/// @param FIE False Iterator End
-/// These two iterators initially point to End() for the two blocks() and
-/// finally point to the first shared instruction in the tail.
-/// Upon return [TIB, TIE), and [FIB, FIE) mark the un-duplicated portions of
-/// two blocks.
-/// @param Dups1 count of duplicated instructions at the beginning of the 2
-/// blocks.
-/// @param Dups2 count of duplicated instructions at the end of the 2 blocks.
-/// @param SkipUnconditionalBranches if true, Don't make sure that
-/// unconditional branches at the end of the blocks are the same. True is
-/// passed when the blocks are analyzable to allow for fallthrough to be
-/// handled.
-/// @return false if the shared portion prevents if conversion.
-bool IfConverter::CountDuplicatedInstructions(
-    MachineBasicBlock::iterator &TIB,
-    MachineBasicBlock::iterator &FIB,
-    MachineBasicBlock::iterator &TIE,
-    MachineBasicBlock::iterator &FIE,
-    unsigned &Dups1, unsigned &Dups2,
-    MachineBasicBlock &TBB, MachineBasicBlock &FBB,
-    bool SkipUnconditionalBranches) const {
-  while (TIB != TIE && FIB != FIE) {
-    // Skip dbg_value instructions. These do not count.
-    TIB = skipDebugInstructionsForward(TIB, TIE);
-    FIB = skipDebugInstructionsForward(FIB, FIE);
-    if (TIB == TIE || FIB == FIE)
-      break;
-    if (!TIB->isIdenticalTo(*FIB))
-      break;
-    // A pred-clobbering instruction in the shared portion prevents
-    // if-conversion.
-    std::vector<MachineOperand> PredDefs;
-    if (TII->DefinesPredicate(*TIB, PredDefs))
-      return false;
-    // If we get all the way to the branch instructions, don't count them.
-    if (!TIB->isBranch())
-      ++Dups1;
-    ++TIB;
-    ++FIB;
-  }
-
-  // Check for already containing all of the block.
-  if (TIB == TIE || FIB == FIE)
-    return true;
-  // Now, in preparation for counting duplicate instructions at the ends of the
-  // blocks, switch to reverse_iterators. Note that getReverse() returns an
-  // iterator that points to the same instruction, unlike std::reverse_iterator.
-  // We have to do our own shifting so that we get the same range.
-  MachineBasicBlock::reverse_iterator RTIE = std::next(TIE.getReverse());
-  MachineBasicBlock::reverse_iterator RFIE = std::next(FIE.getReverse());
-  const MachineBasicBlock::reverse_iterator RTIB = std::next(TIB.getReverse());
-  const MachineBasicBlock::reverse_iterator RFIB = std::next(FIB.getReverse());
-
-  if (!TBB.succ_empty() || !FBB.succ_empty()) {
-    if (SkipUnconditionalBranches) {
-      while (RTIE != RTIB && RTIE->isUnconditionalBranch())
-        ++RTIE;
-      while (RFIE != RFIB && RFIE->isUnconditionalBranch())
-        ++RFIE;
-    }
-  }
-
-  // Count duplicate instructions at the ends of the blocks.
-  while (RTIE != RTIB && RFIE != RFIB) {
-    // Skip dbg_value instructions. These do not count.
-    // Note that these are reverse iterators going forward.
-    RTIE = skipDebugInstructionsForward(RTIE, RTIB);
-    RFIE = skipDebugInstructionsForward(RFIE, RFIB);
-    if (RTIE == RTIB || RFIE == RFIB)
-      break;
-    if (!RTIE->isIdenticalTo(*RFIE))
-      break;
-    // We have to verify that any branch instructions are the same, and then we
-    // don't count them toward the # of duplicate instructions.
-    if (!RTIE->isBranch())
-      ++Dups2;
-    ++RTIE;
-    ++RFIE;
-  }
-  TIE = std::next(RTIE.getReverse());
-  FIE = std::next(RFIE.getReverse());
-  return true;
-}
-
-/// RescanInstructions - Run ScanInstructions on a pair of blocks.
-/// @param TIB - True Iterator Begin, points to first non-shared instruction
-/// @param FIB - False Iterator Begin, points to first non-shared instruction
-/// @param TIE - True Iterator End, points past last non-shared instruction
-/// @param FIE - False Iterator End, points past last non-shared instruction
-/// @param TrueBBI  - BBInfo to update for the true block.
-/// @param FalseBBI - BBInfo to update for the false block.
-/// @returns - false if either block cannot be predicated or if both blocks end
-///   with a predicate-clobbering instruction.
-bool IfConverter::RescanInstructions(
-    MachineBasicBlock::iterator &TIB, MachineBasicBlock::iterator &FIB,
-    MachineBasicBlock::iterator &TIE, MachineBasicBlock::iterator &FIE,
-    BBInfo &TrueBBI, BBInfo &FalseBBI) const {
-  bool BranchUnpredicable = true;
-  TrueBBI.IsUnpredicable = FalseBBI.IsUnpredicable = false;
-  ScanInstructions(TrueBBI, TIB, TIE, BranchUnpredicable);
-  if (TrueBBI.IsUnpredicable)
-    return false;
-  ScanInstructions(FalseBBI, FIB, FIE, BranchUnpredicable);
-  if (FalseBBI.IsUnpredicable)
-    return false;
-  if (TrueBBI.ClobbersPred && FalseBBI.ClobbersPred)
-    return false;
-  return true;
-}
-
-#ifndef NDEBUG
-static void verifySameBranchInstructions(
-    MachineBasicBlock *MBB1,
-    MachineBasicBlock *MBB2) {
-  const MachineBasicBlock::reverse_iterator B1 = MBB1->rend();
-  const MachineBasicBlock::reverse_iterator B2 = MBB2->rend();
-  MachineBasicBlock::reverse_iterator E1 = MBB1->rbegin();
-  MachineBasicBlock::reverse_iterator E2 = MBB2->rbegin();
-  while (E1 != B1 && E2 != B2) {
-    skipDebugInstructionsForward(E1, B1);
-    skipDebugInstructionsForward(E2, B2);
-    if (E1 == B1 && E2 == B2)
-      break;
-
-    if (E1 == B1) {
-      assert(!E2->isBranch() && "Branch mis-match, one block is empty.");
-      break;
-    }
-    if (E2 == B2) {
-      assert(!E1->isBranch() && "Branch mis-match, one block is empty.");
-      break;
-    }
-
-    if (E1->isBranch() || E2->isBranch())
-      assert(E1->isIdenticalTo(*E2) &&
-             "Branch mis-match, branch instructions don't match.");
-    else
-      break;
-    ++E1;
-    ++E2;
-  }
-}
-#endif
-
-/// ValidForkedDiamond - Returns true if the 'true' and 'false' blocks (along
-/// with their common predecessor) form a diamond if a common tail block is
-/// extracted.
-/// While not strictly a diamond, this pattern would form a diamond if
-/// tail-merging had merged the shared tails.
-///           EBB
-///         _/   \_
-///         |     |
-///        TBB   FBB
-///        /  \ /   \
-///  FalseBB TrueBB FalseBB
-/// Currently only handles analyzable branches.
-/// Specifically excludes actual diamonds to avoid overlap.
-bool IfConverter::ValidForkedDiamond(
-    BBInfo &TrueBBI, BBInfo &FalseBBI,
-    unsigned &Dups1, unsigned &Dups2,
-    BBInfo &TrueBBICalc, BBInfo &FalseBBICalc) const {
-  Dups1 = Dups2 = 0;
-  if (TrueBBI.IsBeingAnalyzed || TrueBBI.IsDone ||
-      FalseBBI.IsBeingAnalyzed || FalseBBI.IsDone)
-    return false;
-
-  if (!TrueBBI.IsBrAnalyzable || !FalseBBI.IsBrAnalyzable)
-    return false;
-  // Don't IfConvert blocks that can't be folded into their predecessor.
-  if  (TrueBBI.BB->pred_size() > 1 || FalseBBI.BB->pred_size() > 1)
-    return false;
-
-  // This function is specifically looking for conditional tails, as
-  // unconditional tails are already handled by the standard diamond case.
-  if (TrueBBI.BrCond.size() == 0 ||
-      FalseBBI.BrCond.size() == 0)
-    return false;
-
-  MachineBasicBlock *TT = TrueBBI.TrueBB;
-  MachineBasicBlock *TF = TrueBBI.FalseBB;
-  MachineBasicBlock *FT = FalseBBI.TrueBB;
-  MachineBasicBlock *FF = FalseBBI.FalseBB;
-
-  if (!TT)
-    TT = getNextBlock(*TrueBBI.BB);
-  if (!TF)
-    TF = getNextBlock(*TrueBBI.BB);
-  if (!FT)
-    FT = getNextBlock(*FalseBBI.BB);
-  if (!FF)
-    FF = getNextBlock(*FalseBBI.BB);
-
-  if (!TT || !TF)
-    return false;
-
-  // Check successors. If they don't match, bail.
-  if (!((TT == FT && TF == FF) || (TF == FT && TT == FF)))
-    return false;
-
-  bool FalseReversed = false;
-  if (TF == FT && TT == FF) {
-    // If the branches are opposing, but we can't reverse, don't do it.
-    if (!FalseBBI.IsBrReversible)
-      return false;
-    FalseReversed = true;
-    reverseBranchCondition(FalseBBI);
-  }
-  auto UnReverseOnExit = make_scope_exit([&]() {
-    if (FalseReversed)
-      reverseBranchCondition(FalseBBI);
-  });
-
-  // Count duplicate instructions at the beginning of the true and false blocks.
-  MachineBasicBlock::iterator TIB = TrueBBI.BB->begin();
-  MachineBasicBlock::iterator FIB = FalseBBI.BB->begin();
-  MachineBasicBlock::iterator TIE = TrueBBI.BB->end();
-  MachineBasicBlock::iterator FIE = FalseBBI.BB->end();
-  if(!CountDuplicatedInstructions(TIB, FIB, TIE, FIE, Dups1, Dups2,
-                                  *TrueBBI.BB, *FalseBBI.BB,
-                                  /* SkipUnconditionalBranches */ true))
-    return false;
-
-  TrueBBICalc.BB = TrueBBI.BB;
-  FalseBBICalc.BB = FalseBBI.BB;
-  if (!RescanInstructions(TIB, FIB, TIE, FIE, TrueBBICalc, FalseBBICalc))
-    return false;
-
-  // The size is used to decide whether to if-convert, and the shared portions
-  // are subtracted off. Because of the subtraction, we just use the size that
-  // was calculated by the original ScanInstructions, as it is correct.
-  TrueBBICalc.NonPredSize = TrueBBI.NonPredSize;
-  FalseBBICalc.NonPredSize = FalseBBI.NonPredSize;
-  return true;
-}
-
-/// ValidDiamond - Returns true if the 'true' and 'false' blocks (along
-/// with their common predecessor) forms a valid diamond shape for ifcvt.
-bool IfConverter::ValidDiamond(
-    BBInfo &TrueBBI, BBInfo &FalseBBI,
-    unsigned &Dups1, unsigned &Dups2,
-    BBInfo &TrueBBICalc, BBInfo &FalseBBICalc) const {
-  Dups1 = Dups2 = 0;
-  if (TrueBBI.IsBeingAnalyzed || TrueBBI.IsDone ||
-      FalseBBI.IsBeingAnalyzed || FalseBBI.IsDone)
-    return false;
-
-  MachineBasicBlock *TT = TrueBBI.TrueBB;
-  MachineBasicBlock *FT = FalseBBI.TrueBB;
-
-  if (!TT && blockAlwaysFallThrough(TrueBBI))
-    TT = getNextBlock(*TrueBBI.BB);
-  if (!FT && blockAlwaysFallThrough(FalseBBI))
-    FT = getNextBlock(*FalseBBI.BB);
-  if (TT != FT)
-    return false;
-  if (!TT && (TrueBBI.IsBrAnalyzable || FalseBBI.IsBrAnalyzable))
-    return false;
-  if  (TrueBBI.BB->pred_size() > 1 || FalseBBI.BB->pred_size() > 1)
-    return false;
-
-  // FIXME: Allow true block to have an early exit?
-  if (TrueBBI.FalseBB || FalseBBI.FalseBB)
-    return false;
-
-  // Count duplicate instructions at the beginning and end of the true and
-  // false blocks.
-  // Skip unconditional branches only if we are considering an analyzable
-  // diamond. Otherwise the branches must be the same.
-  bool SkipUnconditionalBranches =
-      TrueBBI.IsBrAnalyzable && FalseBBI.IsBrAnalyzable;
-  MachineBasicBlock::iterator TIB = TrueBBI.BB->begin();
-  MachineBasicBlock::iterator FIB = FalseBBI.BB->begin();
-  MachineBasicBlock::iterator TIE = TrueBBI.BB->end();
-  MachineBasicBlock::iterator FIE = FalseBBI.BB->end();
-  if(!CountDuplicatedInstructions(TIB, FIB, TIE, FIE, Dups1, Dups2,
-                                  *TrueBBI.BB, *FalseBBI.BB,
-                                  SkipUnconditionalBranches))
-    return false;
-
-  TrueBBICalc.BB = TrueBBI.BB;
-  FalseBBICalc.BB = FalseBBI.BB;
-  if (!RescanInstructions(TIB, FIB, TIE, FIE, TrueBBICalc, FalseBBICalc))
-    return false;
-  // The size is used to decide whether to if-convert, and the shared portions
-  // are subtracted off. Because of the subtraction, we just use the size that
-  // was calculated by the original ScanInstructions, as it is correct.
-  TrueBBICalc.NonPredSize = TrueBBI.NonPredSize;
-  FalseBBICalc.NonPredSize = FalseBBI.NonPredSize;
-  return true;
-}
-
-/// AnalyzeBranches - Look at the branches at the end of a block to determine if
-/// the block is predicable.
-void IfConverter::AnalyzeBranches(BBInfo &BBI) {
-  if (BBI.IsDone)
-    return;
-
-  BBI.TrueBB = BBI.FalseBB = nullptr;
-  BBI.BrCond.clear();
-  BBI.IsBrAnalyzable =
-      !TII->analyzeBranch(*BBI.BB, BBI.TrueBB, BBI.FalseBB, BBI.BrCond);
-  if (!BBI.IsBrAnalyzable) {
-    BBI.TrueBB = nullptr;
-    BBI.FalseBB = nullptr;
-    BBI.BrCond.clear();
-  }
-
-  SmallVector<MachineOperand, 4> RevCond(BBI.BrCond.begin(), BBI.BrCond.end());
-  BBI.IsBrReversible = (RevCond.size() == 0) ||
-      !TII->reverseBranchCondition(RevCond);
-  BBI.HasFallThrough = BBI.IsBrAnalyzable && BBI.FalseBB == nullptr;
-
-  if (BBI.BrCond.size()) {
-    // No false branch. This BB must end with a conditional branch and a
-    // fallthrough.
-    if (!BBI.FalseBB)
-      BBI.FalseBB = findFalseBlock(BBI.BB, BBI.TrueBB);
-    if (!BBI.FalseBB) {
-      // Malformed bcc? True and false blocks are the same?
-      BBI.IsUnpredicable = true;
-    }
-  }
-}
-
-/// ScanInstructions - Scan all the instructions in the block to determine if
-/// the block is predicable. In most cases, that means all the instructions
-/// in the block are isPredicable(). Also checks if the block contains any
-/// instruction which can clobber a predicate (e.g. condition code register).
-/// If so, the block is not predicable unless it's the last instruction.
-void IfConverter::ScanInstructions(BBInfo &BBI,
-                                   MachineBasicBlock::iterator &Begin,
-                                   MachineBasicBlock::iterator &End,
-                                   bool BranchUnpredicable) const {
-  if (BBI.IsDone || BBI.IsUnpredicable)
-    return;
-
-  bool AlreadyPredicated = !BBI.Predicate.empty();
-
-  BBI.NonPredSize = 0;
-  BBI.ExtraCost = 0;
-  BBI.ExtraCost2 = 0;
-  BBI.ClobbersPred = false;
-  for (MachineInstr &MI : make_range(Begin, End)) {
-    if (MI.isDebugInstr())
-      continue;
-
-    // It's unsafe to duplicate convergent instructions in this context, so set
-    // BBI.CannotBeCopied to true if MI is convergent.  To see why, consider the
-    // following CFG, which is subject to our "simple" transformation.
-    //
-    //    BB0     // if (c1) goto BB1; else goto BB2;
-    //   /   \
-    //  BB1   |
-    //   |   BB2  // if (c2) goto TBB; else goto FBB;
-    //   |   / |
-    //   |  /  |
-    //   TBB   |
-    //    |    |
-    //    |   FBB
-    //    |
-    //    exit
-    //
-    // Suppose we want to move TBB's contents up into BB1 and BB2 (in BB1 they'd
-    // be unconditional, and in BB2, they'd be predicated upon c2), and suppose
-    // TBB contains a convergent instruction.  This is safe iff doing so does
-    // not add a control-flow dependency to the convergent instruction -- i.e.,
-    // it's safe iff the set of control flows that leads us to the convergent
-    // instruction does not get smaller after the transformation.
-    //
-    // Originally we executed TBB if c1 || c2.  After the transformation, there
-    // are two copies of TBB's instructions.  We get to the first if c1, and we
-    // get to the second if !c1 && c2.
-    //
-    // There are clearly fewer ways to satisfy the condition "c1" than
-    // "c1 || c2".  Since we've shrunk the set of control flows which lead to
-    // our convergent instruction, the transformation is unsafe.
-    if (MI.isNotDuplicable() || MI.isConvergent())
-      BBI.CannotBeCopied = true;
-
-    bool isPredicated = TII->isPredicated(MI);
-    bool isCondBr = BBI.IsBrAnalyzable && MI.isConditionalBranch();
-
-    if (BranchUnpredicable && MI.isBranch()) {
-      BBI.IsUnpredicable = true;
-      return;
-    }
-
-    // A conditional branch is not predicable, but it may be eliminated.
-    if (isCondBr)
-      continue;
-
-    if (!isPredicated) {
-      BBI.NonPredSize++;
-      unsigned ExtraPredCost = TII->getPredicationCost(MI);
-      unsigned NumCycles = SchedModel.computeInstrLatency(&MI, false);
-      if (NumCycles > 1)
-        BBI.ExtraCost += NumCycles-1;
-      BBI.ExtraCost2 += ExtraPredCost;
-    } else if (!AlreadyPredicated) {
-      // FIXME: This instruction is already predicated before the
-      // if-conversion pass. It's probably something like a conditional move.
-      // Mark this block unpredicable for now.
-      BBI.IsUnpredicable = true;
-      return;
-    }
-
-    if (BBI.ClobbersPred && !isPredicated) {
-      // Predicate modification instruction should end the block (except for
-      // already predicated instructions and end of block branches).
-      // Predicate may have been modified, the subsequent (currently)
-      // unpredicated instructions cannot be correctly predicated.
-      BBI.IsUnpredicable = true;
-      return;
-    }
-
-    // FIXME: Make use of PredDefs? e.g. ADDC, SUBC sets predicates but are
-    // still potentially predicable.
-    std::vector<MachineOperand> PredDefs;
-    if (TII->DefinesPredicate(MI, PredDefs))
-      BBI.ClobbersPred = true;
-
-    if (!TII->isPredicable(MI)) {
-      BBI.IsUnpredicable = true;
-      return;
-    }
-  }
-}
-
-/// Determine if the block is a suitable candidate to be predicated by the
-/// specified predicate.
-/// @param BBI BBInfo for the block to check
-/// @param Pred Predicate array for the branch that leads to BBI
-/// @param isTriangle true if the Analysis is for a triangle
-/// @param RevBranch true if Reverse(Pred) leads to BBI (e.g. BBI is the false
-///        case
-/// @param hasCommonTail true if BBI shares a tail with a sibling block that
-///        contains any instruction that would make the block unpredicable.
-bool IfConverter::FeasibilityAnalysis(BBInfo &BBI,
-                                      SmallVectorImpl<MachineOperand> &Pred,
-                                      bool isTriangle, bool RevBranch,
-                                      bool hasCommonTail) {
-  // If the block is dead or unpredicable, then it cannot be predicated.
-  // Two blocks may share a common unpredicable tail, but this doesn't prevent
-  // them from being if-converted. The non-shared portion is assumed to have
-  // been checked
-  if (BBI.IsDone || (BBI.IsUnpredicable && !hasCommonTail))
-    return false;
-
-  // If it is already predicated but we couldn't analyze its terminator, the
-  // latter might fallthrough, but we can't determine where to.
-  // Conservatively avoid if-converting again.
-  if (BBI.Predicate.size() && !BBI.IsBrAnalyzable)
-    return false;
-
-  // If it is already predicated, check if the new predicate subsumes
-  // its predicate.
-  if (BBI.Predicate.size() && !TII->SubsumesPredicate(Pred, BBI.Predicate))
-    return false;
-
-  if (!hasCommonTail && BBI.BrCond.size()) {
-    if (!isTriangle)
-      return false;
-
-    // Test predicate subsumption.
-    SmallVector<MachineOperand, 4> RevPred(Pred.begin(), Pred.end());
-    SmallVector<MachineOperand, 4> Cond(BBI.BrCond.begin(), BBI.BrCond.end());
-    if (RevBranch) {
-      if (TII->reverseBranchCondition(Cond))
-        return false;
-    }
-    if (TII->reverseBranchCondition(RevPred) ||
-        !TII->SubsumesPredicate(Cond, RevPred))
-      return false;
-  }
-
-  return true;
-}
-
-/// Analyze the structure of the sub-CFG starting from the specified block.
-/// Record its successors and whether it looks like an if-conversion candidate.
-void IfConverter::AnalyzeBlock(
-    MachineBasicBlock &MBB, std::vector<std::unique_ptr<IfcvtToken>> &Tokens) {
-  struct BBState {
-    BBState(MachineBasicBlock &MBB) : MBB(&MBB), SuccsAnalyzed(false) {}
-    MachineBasicBlock *MBB;
-
-    /// This flag is true if MBB's successors have been analyzed.
-    bool SuccsAnalyzed;
-  };
-
-  // Push MBB to the stack.
-  SmallVector<BBState, 16> BBStack(1, MBB);
-
-  while (!BBStack.empty()) {
-    BBState &State = BBStack.back();
-    MachineBasicBlock *BB = State.MBB;
-    BBInfo &BBI = BBAnalysis[BB->getNumber()];
-
-    if (!State.SuccsAnalyzed) {
-      if (BBI.IsAnalyzed || BBI.IsBeingAnalyzed) {
-        BBStack.pop_back();
-        continue;
-      }
-
-      BBI.BB = BB;
-      BBI.IsBeingAnalyzed = true;
-
-      AnalyzeBranches(BBI);
-      MachineBasicBlock::iterator Begin = BBI.BB->begin();
-      MachineBasicBlock::iterator End = BBI.BB->end();
-      ScanInstructions(BBI, Begin, End);
-
-      // Unanalyzable or ends with fallthrough or unconditional branch, or if is
-      // not considered for ifcvt anymore.
-      if (!BBI.IsBrAnalyzable || BBI.BrCond.empty() || BBI.IsDone) {
-        BBI.IsBeingAnalyzed = false;
-        BBI.IsAnalyzed = true;
-        BBStack.pop_back();
-        continue;
-      }
-
-      // Do not ifcvt if either path is a back edge to the entry block.
-      if (BBI.TrueBB == BB || BBI.FalseBB == BB) {
-        BBI.IsBeingAnalyzed = false;
-        BBI.IsAnalyzed = true;
-        BBStack.pop_back();
-        continue;
-      }
-
-      // Do not ifcvt if true and false fallthrough blocks are the same.
-      if (!BBI.FalseBB) {
-        BBI.IsBeingAnalyzed = false;
-        BBI.IsAnalyzed = true;
-        BBStack.pop_back();
-        continue;
-      }
-
-      // Push the False and True blocks to the stack.
-      State.SuccsAnalyzed = true;
-      BBStack.push_back(*BBI.FalseBB);
-      BBStack.push_back(*BBI.TrueBB);
-      continue;
-    }
-
-    BBInfo &TrueBBI = BBAnalysis[BBI.TrueBB->getNumber()];
-    BBInfo &FalseBBI = BBAnalysis[BBI.FalseBB->getNumber()];
-
-    if (TrueBBI.IsDone && FalseBBI.IsDone) {
-      BBI.IsBeingAnalyzed = false;
-      BBI.IsAnalyzed = true;
-      BBStack.pop_back();
-      continue;
-    }
-
-    SmallVector<MachineOperand, 4>
-        RevCond(BBI.BrCond.begin(), BBI.BrCond.end());
-    bool CanRevCond = !TII->reverseBranchCondition(RevCond);
-
-    unsigned Dups = 0;
-    unsigned Dups2 = 0;
-    bool TNeedSub = !TrueBBI.Predicate.empty();
-    bool FNeedSub = !FalseBBI.Predicate.empty();
-    bool Enqueued = false;
-
-    BranchProbability Prediction = MBPI->getEdgeProbability(BB, TrueBBI.BB);
-
-    if (CanRevCond) {
-      BBInfo TrueBBICalc, FalseBBICalc;
-      auto feasibleDiamond = [&]() {
-        bool MeetsSize = MeetIfcvtSizeLimit(
-            *TrueBBI.BB, (TrueBBICalc.NonPredSize - (Dups + Dups2) +
-                          TrueBBICalc.ExtraCost), TrueBBICalc.ExtraCost2,
-            *FalseBBI.BB, (FalseBBICalc.NonPredSize - (Dups + Dups2) +
-                           FalseBBICalc.ExtraCost), FalseBBICalc.ExtraCost2,
-            Prediction);
-        bool TrueFeasible = FeasibilityAnalysis(TrueBBI, BBI.BrCond,
-                                                /* IsTriangle */ false, /* RevCond */ false,
-                                                /* hasCommonTail */ true);
-        bool FalseFeasible = FeasibilityAnalysis(FalseBBI, RevCond,
-                                                 /* IsTriangle */ false, /* RevCond */ false,
-                                                 /* hasCommonTail */ true);
-        return MeetsSize && TrueFeasible && FalseFeasible;
-      };
-
-      if (ValidDiamond(TrueBBI, FalseBBI, Dups, Dups2,
-                       TrueBBICalc, FalseBBICalc)) {
-        if (feasibleDiamond()) {
-          // Diamond:
-          //   EBB
-          //   / \_
-          //  |   |
-          // TBB FBB
-          //   \ /
-          //  TailBB
-          // Note TailBB can be empty.
-          Tokens.push_back(llvm::make_unique<IfcvtToken>(
-              BBI, ICDiamond, TNeedSub | FNeedSub, Dups, Dups2,
-              (bool) TrueBBICalc.ClobbersPred, (bool) FalseBBICalc.ClobbersPred));
-          Enqueued = true;
-        }
-      } else if (ValidForkedDiamond(TrueBBI, FalseBBI, Dups, Dups2,
-                                    TrueBBICalc, FalseBBICalc)) {
-        if (feasibleDiamond()) {
-          // ForkedDiamond:
-          // if TBB and FBB have a common tail that includes their conditional
-          // branch instructions, then we can If Convert this pattern.
-          //          EBB
-          //         _/ \_
-          //         |   |
-          //        TBB  FBB
-          //        / \ /   \
-          //  FalseBB TrueBB FalseBB
-          //
-          Tokens.push_back(llvm::make_unique<IfcvtToken>(
-              BBI, ICForkedDiamond, TNeedSub | FNeedSub, Dups, Dups2,
-              (bool) TrueBBICalc.ClobbersPred, (bool) FalseBBICalc.ClobbersPred));
-          Enqueued = true;
-        }
-      }
-    }
-
-    if (ValidTriangle(TrueBBI, FalseBBI, false, Dups, Prediction) &&
-        MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize + TrueBBI.ExtraCost,
-                           TrueBBI.ExtraCost2, Prediction) &&
-        FeasibilityAnalysis(TrueBBI, BBI.BrCond, true)) {
-      // Triangle:
-      //   EBB
-      //   | \_
-      //   |  |
-      //   | TBB
-      //   |  /
-      //   FBB
-      Tokens.push_back(
-          llvm::make_unique<IfcvtToken>(BBI, ICTriangle, TNeedSub, Dups));
-      Enqueued = true;
-    }
-
-    if (ValidTriangle(TrueBBI, FalseBBI, true, Dups, Prediction) &&
-        MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize + TrueBBI.ExtraCost,
-                           TrueBBI.ExtraCost2, Prediction) &&
-        FeasibilityAnalysis(TrueBBI, BBI.BrCond, true, true)) {
-      Tokens.push_back(
-          llvm::make_unique<IfcvtToken>(BBI, ICTriangleRev, TNeedSub, Dups));
-      Enqueued = true;
-    }
-
-    if (ValidSimple(TrueBBI, Dups, Prediction) &&
-        MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize + TrueBBI.ExtraCost,
-                           TrueBBI.ExtraCost2, Prediction) &&
-        FeasibilityAnalysis(TrueBBI, BBI.BrCond)) {
-      // Simple (split, no rejoin):
-      //   EBB
-      //   | \_
-      //   |  |
-      //   | TBB---> exit
-      //   |
-      //   FBB
-      Tokens.push_back(
-          llvm::make_unique<IfcvtToken>(BBI, ICSimple, TNeedSub, Dups));
-      Enqueued = true;
-    }
-
-    if (CanRevCond) {
-      // Try the other path...
-      if (ValidTriangle(FalseBBI, TrueBBI, false, Dups,
-                        Prediction.getCompl()) &&
-          MeetIfcvtSizeLimit(*FalseBBI.BB,
-                             FalseBBI.NonPredSize + FalseBBI.ExtraCost,
-                             FalseBBI.ExtraCost2, Prediction.getCompl()) &&
-          FeasibilityAnalysis(FalseBBI, RevCond, true)) {
-        Tokens.push_back(llvm::make_unique<IfcvtToken>(BBI, ICTriangleFalse,
-                                                       FNeedSub, Dups));
-        Enqueued = true;
-      }
-
-      if (ValidTriangle(FalseBBI, TrueBBI, true, Dups,
-                        Prediction.getCompl()) &&
-          MeetIfcvtSizeLimit(*FalseBBI.BB,
-                             FalseBBI.NonPredSize + FalseBBI.ExtraCost,
-                           FalseBBI.ExtraCost2, Prediction.getCompl()) &&
-        FeasibilityAnalysis(FalseBBI, RevCond, true, true)) {
-        Tokens.push_back(
-            llvm::make_unique<IfcvtToken>(BBI, ICTriangleFRev, FNeedSub, Dups));
-        Enqueued = true;
-      }
-
-      if (ValidSimple(FalseBBI, Dups, Prediction.getCompl()) &&
-          MeetIfcvtSizeLimit(*FalseBBI.BB,
-                             FalseBBI.NonPredSize + FalseBBI.ExtraCost,
-                             FalseBBI.ExtraCost2, Prediction.getCompl()) &&
-          FeasibilityAnalysis(FalseBBI, RevCond)) {
-        Tokens.push_back(
-            llvm::make_unique<IfcvtToken>(BBI, ICSimpleFalse, FNeedSub, Dups));
-        Enqueued = true;
-      }
-    }
-
-    BBI.IsEnqueued = Enqueued;
-    BBI.IsBeingAnalyzed = false;
-    BBI.IsAnalyzed = true;
-    BBStack.pop_back();
-  }
-}
-
-/// Analyze all blocks and find entries for all if-conversion candidates.
-void IfConverter::AnalyzeBlocks(
-    MachineFunction &MF, std::vector<std::unique_ptr<IfcvtToken>> &Tokens) {
-  for (MachineBasicBlock &MBB : MF)
-    AnalyzeBlock(MBB, Tokens);
-
-  // Sort to favor more complex ifcvt scheme.
-  llvm::stable_sort(Tokens, IfcvtTokenCmp);
-}
-
-/// Returns true either if ToMBB is the next block after MBB or that all the
-/// intervening blocks are empty (given MBB can fall through to its next block).
-static bool canFallThroughTo(MachineBasicBlock &MBB, MachineBasicBlock &ToMBB) {
-  MachineFunction::iterator PI = MBB.getIterator();
-  MachineFunction::iterator I = std::next(PI);
-  MachineFunction::iterator TI = ToMBB.getIterator();
-  MachineFunction::iterator E = MBB.getParent()->end();
-  while (I != TI) {
-    // Check isSuccessor to avoid case where the next block is empty, but
-    // it's not a successor.
-    if (I == E || !I->empty() || !PI->isSuccessor(&*I))
-      return false;
-    PI = I++;
-  }
-  // Finally see if the last I is indeed a successor to PI.
-  return PI->isSuccessor(&*I);
-}
-
-/// Invalidate predecessor BB info so it would be re-analyzed to determine if it
-/// can be if-converted. If predecessor is already enqueued, dequeue it!
-void IfConverter::InvalidatePreds(MachineBasicBlock &MBB) {
-  for (const MachineBasicBlock *Predecessor : MBB.predecessors()) {
-    BBInfo &PBBI = BBAnalysis[Predecessor->getNumber()];
-    if (PBBI.IsDone || PBBI.BB == &MBB)
-      continue;
-    PBBI.IsAnalyzed = false;
-    PBBI.IsEnqueued = false;
-  }
-}
-
-/// Inserts an unconditional branch from \p MBB to \p ToMBB.
-static void InsertUncondBranch(MachineBasicBlock &MBB, MachineBasicBlock &ToMBB,
-                               const TargetInstrInfo *TII) {
-  DebugLoc dl;  // FIXME: this is nowhere
-  SmallVector<MachineOperand, 0> NoCond;
-  TII->insertBranch(MBB, &ToMBB, nullptr, NoCond, dl);
-}
-
-/// Behaves like LiveRegUnits::StepForward() but also adds implicit uses to all
-/// values defined in MI which are also live/used by MI.
-static void UpdatePredRedefs(MachineInstr &MI, LivePhysRegs &Redefs) {
-  const TargetRegisterInfo *TRI = MI.getMF()->getSubtarget().getRegisterInfo();
-
-  // Before stepping forward past MI, remember which regs were live
-  // before MI. This is needed to set the Undef flag only when reg is
-  // dead.
-  SparseSet<MCPhysReg, identity<MCPhysReg>> LiveBeforeMI;
-  LiveBeforeMI.setUniverse(TRI->getNumRegs());
-  for (unsigned Reg : Redefs)
-    LiveBeforeMI.insert(Reg);
-
-  SmallVector<std::pair<MCPhysReg, const MachineOperand*>, 4> Clobbers;
-  Redefs.stepForward(MI, Clobbers);
-
-  // Now add the implicit uses for each of the clobbered values.
-  for (auto Clobber : Clobbers) {
-    // FIXME: Const cast here is nasty, but better than making StepForward
-    // take a mutable instruction instead of const.
-    unsigned Reg = Clobber.first;
-    MachineOperand &Op = const_cast<MachineOperand&>(*Clobber.second);
-    MachineInstr *OpMI = Op.getParent();
-    MachineInstrBuilder MIB(*OpMI->getMF(), OpMI);
-    if (Op.isRegMask()) {
-      // First handle regmasks.  They clobber any entries in the mask which
-      // means that we need a def for those registers.
-      if (LiveBeforeMI.count(Reg))
-        MIB.addReg(Reg, RegState::Implicit);
-
-      // We also need to add an implicit def of this register for the later
-      // use to read from.
-      // For the register allocator to have allocated a register clobbered
-      // by the call which is used later, it must be the case that
-      // the call doesn't return.
-      MIB.addReg(Reg, RegState::Implicit | RegState::Define);
-      continue;
-    }
-    if (LiveBeforeMI.count(Reg))
-      MIB.addReg(Reg, RegState::Implicit);
-    else {
-      bool HasLiveSubReg = false;
-      for (MCSubRegIterator S(Reg, TRI); S.isValid(); ++S) {
-        if (!LiveBeforeMI.count(*S))
-          continue;
-        HasLiveSubReg = true;
-        break;
-      }
-      if (HasLiveSubReg)
-        MIB.addReg(Reg, RegState::Implicit);
-    }
-  }
-}
-
-/// If convert a simple (split, no rejoin) sub-CFG.
-bool IfConverter::IfConvertSimple(BBInfo &BBI, IfcvtKind Kind) {
-  BBInfo &TrueBBI  = BBAnalysis[BBI.TrueBB->getNumber()];
-  BBInfo &FalseBBI = BBAnalysis[BBI.FalseBB->getNumber()];
-  BBInfo *CvtBBI = &TrueBBI;
-  BBInfo *NextBBI = &FalseBBI;
-
-  SmallVector<MachineOperand, 4> Cond(BBI.BrCond.begin(), BBI.BrCond.end());
-  if (Kind == ICSimpleFalse)
-    std::swap(CvtBBI, NextBBI);
-
-  MachineBasicBlock &CvtMBB = *CvtBBI->BB;
-  MachineBasicBlock &NextMBB = *NextBBI->BB;
-  if (CvtBBI->IsDone ||
-      (CvtBBI->CannotBeCopied && CvtMBB.pred_size() > 1)) {
-    // Something has changed. It's no longer safe to predicate this block.
-    BBI.IsAnalyzed = false;
-    CvtBBI->IsAnalyzed = false;
-    return false;
-  }
-
-  if (CvtMBB.hasAddressTaken())
-    // Conservatively abort if-conversion if BB's address is taken.
-    return false;
-
-  if (Kind == ICSimpleFalse)
-    if (TII->reverseBranchCondition(Cond))
-      llvm_unreachable("Unable to reverse branch condition!");
-
-  Redefs.init(*TRI);
-
-  if (MRI->tracksLiveness()) {
-    // Initialize liveins to the first BB. These are potentially redefined by
-    // predicated instructions.
-    Redefs.addLiveIns(CvtMBB);
-    Redefs.addLiveIns(NextMBB);
-  }
-
-  // Remove the branches from the entry so we can add the contents of the true
-  // block to it.
-  BBI.NonPredSize -= TII->removeBranch(*BBI.BB);
-
-  if (CvtMBB.pred_size() > 1) {
-    // Copy instructions in the true block, predicate them, and add them to
-    // the entry block.
-    CopyAndPredicateBlock(BBI, *CvtBBI, Cond);
-
-    // Keep the CFG updated.
-    BBI.BB->removeSuccessor(&CvtMBB, true);
-  } else {
-    // Predicate the instructions in the true block.
-    PredicateBlock(*CvtBBI, CvtMBB.end(), Cond);
-
-    // Merge converted block into entry block. The BB to Cvt edge is removed
-    // by MergeBlocks.
-    MergeBlocks(BBI, *CvtBBI);
-  }
-
-  bool IterIfcvt = true;
-  if (!canFallThroughTo(*BBI.BB, NextMBB)) {
-    InsertUncondBranch(*BBI.BB, NextMBB, TII);
-    BBI.HasFallThrough = false;
-    // Now ifcvt'd block will look like this:
-    // BB:
-    // ...
-    // t, f = cmp
-    // if t op
-    // b BBf
-    //
-    // We cannot further ifcvt this block because the unconditional branch
-    // will have to be predicated on the new condition, that will not be
-    // available if cmp executes.
-    IterIfcvt = false;
-  }
-
-  // Update block info. BB can be iteratively if-converted.
-  if (!IterIfcvt)
-    BBI.IsDone = true;
-  InvalidatePreds(*BBI.BB);
-  CvtBBI->IsDone = true;
-
-  // FIXME: Must maintain LiveIns.
-  return true;
-}
-
-/// If convert a triangle sub-CFG.
-bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) {
-  BBInfo &TrueBBI = BBAnalysis[BBI.TrueBB->getNumber()];
-  BBInfo &FalseBBI = BBAnalysis[BBI.FalseBB->getNumber()];
-  BBInfo *CvtBBI = &TrueBBI;
-  BBInfo *NextBBI = &FalseBBI;
-  DebugLoc dl;  // FIXME: this is nowhere
-
-  SmallVector<MachineOperand, 4> Cond(BBI.BrCond.begin(), BBI.BrCond.end());
-  if (Kind == ICTriangleFalse || Kind == ICTriangleFRev)
-    std::swap(CvtBBI, NextBBI);
-
-  MachineBasicBlock &CvtMBB = *CvtBBI->BB;
-  MachineBasicBlock &NextMBB = *NextBBI->BB;
-  if (CvtBBI->IsDone ||
-      (CvtBBI->CannotBeCopied && CvtMBB.pred_size() > 1)) {
-    // Something has changed. It's no longer safe to predicate this block.
-    BBI.IsAnalyzed = false;
-    CvtBBI->IsAnalyzed = false;
-    return false;
-  }
-
-  if (CvtMBB.hasAddressTaken())
-    // Conservatively abort if-conversion if BB's address is taken.
-    return false;
-
-  if (Kind == ICTriangleFalse || Kind == ICTriangleFRev)
-    if (TII->reverseBranchCondition(Cond))
-      llvm_unreachable("Unable to reverse branch condition!");
-
-  if (Kind == ICTriangleRev || Kind == ICTriangleFRev) {
-    if (reverseBranchCondition(*CvtBBI)) {
-      // BB has been changed, modify its predecessors (except for this
-      // one) so they don't get ifcvt'ed based on bad intel.
-      for (MachineBasicBlock *PBB : CvtMBB.predecessors()) {
-        if (PBB == BBI.BB)
-          continue;
-        BBInfo &PBBI = BBAnalysis[PBB->getNumber()];
-        if (PBBI.IsEnqueued) {
-          PBBI.IsAnalyzed = false;
-          PBBI.IsEnqueued = false;
-        }
-      }
-    }
-  }
-
-  // Initialize liveins to the first BB. These are potentially redefined by
-  // predicated instructions.
-  Redefs.init(*TRI);
-  if (MRI->tracksLiveness()) {
-    Redefs.addLiveIns(CvtMBB);
-    Redefs.addLiveIns(NextMBB);
-  }
-
-  bool HasEarlyExit = CvtBBI->FalseBB != nullptr;
-  BranchProbability CvtNext, CvtFalse, BBNext, BBCvt;
-
-  if (HasEarlyExit) {
-    // Get probabilities before modifying CvtMBB and BBI.BB.
-    CvtNext = MBPI->getEdgeProbability(&CvtMBB, &NextMBB);
-    CvtFalse = MBPI->getEdgeProbability(&CvtMBB, CvtBBI->FalseBB);
-    BBNext = MBPI->getEdgeProbability(BBI.BB, &NextMBB);
-    BBCvt = MBPI->getEdgeProbability(BBI.BB, &CvtMBB);
-  }
-
-  // Remove the branches from the entry so we can add the contents of the true
-  // block to it.
-  BBI.NonPredSize -= TII->removeBranch(*BBI.BB);
-
-  if (CvtMBB.pred_size() > 1) {
-    // Copy instructions in the true block, predicate them, and add them to
-    // the entry block.
-    CopyAndPredicateBlock(BBI, *CvtBBI, Cond, true);
-  } else {
-    // Predicate the 'true' block after removing its branch.
-    CvtBBI->NonPredSize -= TII->removeBranch(CvtMBB);
-    PredicateBlock(*CvtBBI, CvtMBB.end(), Cond);
-
-    // Now merge the entry of the triangle with the true block.
-    MergeBlocks(BBI, *CvtBBI, false);
-  }
-
-  // Keep the CFG updated.
-  BBI.BB->removeSuccessor(&CvtMBB, true);
-
-  // If 'true' block has a 'false' successor, add an exit branch to it.
-  if (HasEarlyExit) {
-    SmallVector<MachineOperand, 4> RevCond(CvtBBI->BrCond.begin(),
-                                           CvtBBI->BrCond.end());
-    if (TII->reverseBranchCondition(RevCond))
-      llvm_unreachable("Unable to reverse branch condition!");
-
-    // Update the edge probability for both CvtBBI->FalseBB and NextBBI.
-    // NewNext = New_Prob(BBI.BB, NextMBB) =
-    //   Prob(BBI.BB, NextMBB) +
-    //   Prob(BBI.BB, CvtMBB) * Prob(CvtMBB, NextMBB)
-    // NewFalse = New_Prob(BBI.BB, CvtBBI->FalseBB) =
-    //   Prob(BBI.BB, CvtMBB) * Prob(CvtMBB, CvtBBI->FalseBB)
-    auto NewTrueBB = getNextBlock(*BBI.BB);
-    auto NewNext = BBNext + BBCvt * CvtNext;
-    auto NewTrueBBIter = find(BBI.BB->successors(), NewTrueBB);
-    if (NewTrueBBIter != BBI.BB->succ_end())
-      BBI.BB->setSuccProbability(NewTrueBBIter, NewNext);
-
-    auto NewFalse = BBCvt * CvtFalse;
-    TII->insertBranch(*BBI.BB, CvtBBI->FalseBB, nullptr, RevCond, dl);
-    BBI.BB->addSuccessor(CvtBBI->FalseBB, NewFalse);
-  }
-
-  // Merge in the 'false' block if the 'false' block has no other
-  // predecessors. Otherwise, add an unconditional branch to 'false'.
-  bool FalseBBDead = false;
-  bool IterIfcvt = true;
-  bool isFallThrough = canFallThroughTo(*BBI.BB, NextMBB);
-  if (!isFallThrough) {
-    // Only merge them if the true block does not fallthrough to the false
-    // block. By not merging them, we make it possible to iteratively
-    // ifcvt the blocks.
-    if (!HasEarlyExit &&
-        NextMBB.pred_size() == 1 && !NextBBI->HasFallThrough &&
-        !NextMBB.hasAddressTaken()) {
-      MergeBlocks(BBI, *NextBBI);
-      FalseBBDead = true;
-    } else {
-      InsertUncondBranch(*BBI.BB, NextMBB, TII);
-      BBI.HasFallThrough = false;
-    }
-    // Mixed predicated and unpredicated code. This cannot be iteratively
-    // predicated.
-    IterIfcvt = false;
-  }
-
-  // Update block info. BB can be iteratively if-converted.
-  if (!IterIfcvt)
-    BBI.IsDone = true;
-  InvalidatePreds(*BBI.BB);
-  CvtBBI->IsDone = true;
-  if (FalseBBDead)
-    NextBBI->IsDone = true;
-
-  // FIXME: Must maintain LiveIns.
-  return true;
-}
-
-/// Common code shared between diamond conversions.
-/// \p BBI, \p TrueBBI, and \p FalseBBI form the diamond shape.
-/// \p NumDups1 - number of shared instructions at the beginning of \p TrueBBI
-///               and FalseBBI
-/// \p NumDups2 - number of shared instructions at the end of \p TrueBBI
-///               and \p FalseBBI
-/// \p RemoveBranch - Remove the common branch of the two blocks before
-///                   predicating. Only false for unanalyzable fallthrough
-///                   cases. The caller will replace the branch if necessary.
-/// \p MergeAddEdges - Add successor edges when merging blocks. Only false for
-///                    unanalyzable fallthrough
-bool IfConverter::IfConvertDiamondCommon(
-    BBInfo &BBI, BBInfo &TrueBBI, BBInfo &FalseBBI,
-    unsigned NumDups1, unsigned NumDups2,
-    bool TClobbersPred, bool FClobbersPred,
-    bool RemoveBranch, bool MergeAddEdges) {
-
-  if (TrueBBI.IsDone || FalseBBI.IsDone ||
-      TrueBBI.BB->pred_size() > 1 || FalseBBI.BB->pred_size() > 1) {
-    // Something has changed. It's no longer safe to predicate these blocks.
-    BBI.IsAnalyzed = false;
-    TrueBBI.IsAnalyzed = false;
-    FalseBBI.IsAnalyzed = false;
-    return false;
-  }
-
-  if (TrueBBI.BB->hasAddressTaken() || FalseBBI.BB->hasAddressTaken())
-    // Conservatively abort if-conversion if either BB has its address taken.
-    return false;
-
-  // Put the predicated instructions from the 'true' block before the
-  // instructions from the 'false' block, unless the true block would clobber
-  // the predicate, in which case, do the opposite.
-  BBInfo *BBI1 = &TrueBBI;
-  BBInfo *BBI2 = &FalseBBI;
-  SmallVector<MachineOperand, 4> RevCond(BBI.BrCond.begin(), BBI.BrCond.end());
-  if (TII->reverseBranchCondition(RevCond))
-    llvm_unreachable("Unable to reverse branch condition!");
-  SmallVector<MachineOperand, 4> *Cond1 = &BBI.BrCond;
-  SmallVector<MachineOperand, 4> *Cond2 = &RevCond;
-
-  // Figure out the more profitable ordering.
-  bool DoSwap = false;
-  if (TClobbersPred && !FClobbersPred)
-    DoSwap = true;
-  else if (!TClobbersPred && !FClobbersPred) {
-    if (TrueBBI.NonPredSize > FalseBBI.NonPredSize)
-      DoSwap = true;
-  } else if (TClobbersPred && FClobbersPred)
-    llvm_unreachable("Predicate info cannot be clobbered by both sides.");
-  if (DoSwap) {
-    std::swap(BBI1, BBI2);
-    std::swap(Cond1, Cond2);
-  }
-
-  // Remove the conditional branch from entry to the blocks.
-  BBI.NonPredSize -= TII->removeBranch(*BBI.BB);
-
-  MachineBasicBlock &MBB1 = *BBI1->BB;
-  MachineBasicBlock &MBB2 = *BBI2->BB;
-
-  // Initialize the Redefs:
-  // - BB2 live-in regs need implicit uses before being redefined by BB1
-  //   instructions.
-  // - BB1 live-out regs need implicit uses before being redefined by BB2
-  //   instructions. We start with BB1 live-ins so we have the live-out regs
-  //   after tracking the BB1 instructions.
-  Redefs.init(*TRI);
-  if (MRI->tracksLiveness()) {
-    Redefs.addLiveIns(MBB1);
-    Redefs.addLiveIns(MBB2);
-  }
-
-  // Remove the duplicated instructions at the beginnings of both paths.
-  // Skip dbg_value instructions.
-  MachineBasicBlock::iterator DI1 = MBB1.getFirstNonDebugInstr();
-  MachineBasicBlock::iterator DI2 = MBB2.getFirstNonDebugInstr();
-  BBI1->NonPredSize -= NumDups1;
-  BBI2->NonPredSize -= NumDups1;
-
-  // Skip past the dups on each side separately since there may be
-  // differing dbg_value entries. NumDups1 can include a "return"
-  // instruction, if it's not marked as "branch".
-  for (unsigned i = 0; i < NumDups1; ++DI1) {
-    if (DI1 == MBB1.end())
-      break;
-    if (!DI1->isDebugInstr())
-      ++i;
-  }
-  while (NumDups1 != 0) {
-    ++DI2;
-    if (DI2 == MBB2.end())
-      break;
-    if (!DI2->isDebugInstr())
-      --NumDups1;
-  }
-
-  if (MRI->tracksLiveness()) {
-    for (const MachineInstr &MI : make_range(MBB1.begin(), DI1)) {
-      SmallVector<std::pair<MCPhysReg, const MachineOperand*>, 4> Dummy;
-      Redefs.stepForward(MI, Dummy);
-    }
-  }
-
-  BBI.BB->splice(BBI.BB->end(), &MBB1, MBB1.begin(), DI1);
-  MBB2.erase(MBB2.begin(), DI2);
-
-  // The branches have been checked to match, so it is safe to remove the
-  // branch in BB1 and rely on the copy in BB2. The complication is that
-  // the blocks may end with a return instruction, which may or may not
-  // be marked as "branch". If it's not, then it could be included in
-  // "dups1", leaving the blocks potentially empty after moving the common
-  // duplicates.
-#ifndef NDEBUG
-  // Unanalyzable branches must match exactly. Check that now.
-  if (!BBI1->IsBrAnalyzable)
-    verifySameBranchInstructions(&MBB1, &MBB2);
-#endif
-  // Remove duplicated instructions from the tail of MBB1: any branch
-  // instructions, and the common instructions counted by NumDups2.
-  DI1 = MBB1.end();
-  while (DI1 != MBB1.begin()) {
-    MachineBasicBlock::iterator Prev = std::prev(DI1);
-    if (!Prev->isBranch() && !Prev->isDebugInstr())
-      break;
-    DI1 = Prev;
-  }
-  for (unsigned i = 0; i != NumDups2; ) {
-    // NumDups2 only counted non-dbg_value instructions, so this won't
-    // run off the head of the list.
-    assert(DI1 != MBB1.begin());
-    --DI1;
-    // skip dbg_value instructions
-    if (!DI1->isDebugInstr())
-      ++i;
-  }
-  MBB1.erase(DI1, MBB1.end());
-
-  DI2 = BBI2->BB->end();
-  // The branches have been checked to match. Skip over the branch in the false
-  // block so that we don't try to predicate it.
-  if (RemoveBranch)
-    BBI2->NonPredSize -= TII->removeBranch(*BBI2->BB);
-  else {
-    // Make DI2 point to the end of the range where the common "tail"
-    // instructions could be found.
-    while (DI2 != MBB2.begin()) {
-      MachineBasicBlock::iterator Prev = std::prev(DI2);
-      if (!Prev->isBranch() && !Prev->isDebugInstr())
-        break;
-      DI2 = Prev;
-    }
-  }
-  while (NumDups2 != 0) {
-    // NumDups2 only counted non-dbg_value instructions, so this won't
-    // run off the head of the list.
-    assert(DI2 != MBB2.begin());
-    --DI2;
-    // skip dbg_value instructions
-    if (!DI2->isDebugInstr())
-      --NumDups2;
-  }
-
-  // Remember which registers would later be defined by the false block.
-  // This allows us not to predicate instructions in the true block that would
-  // later be re-defined. That is, rather than
-  //   subeq  r0, r1, #1
-  //   addne  r0, r1, #1
-  // generate:
-  //   sub    r0, r1, #1
-  //   addne  r0, r1, #1
-  SmallSet<MCPhysReg, 4> RedefsByFalse;
-  SmallSet<MCPhysReg, 4> ExtUses;
-  if (TII->isProfitableToUnpredicate(MBB1, MBB2)) {
-    for (const MachineInstr &FI : make_range(MBB2.begin(), DI2)) {
-      if (FI.isDebugInstr())
-        continue;
-      SmallVector<MCPhysReg, 4> Defs;
-      for (const MachineOperand &MO : FI.operands()) {
-        if (!MO.isReg())
-          continue;
-        unsigned Reg = MO.getReg();
-        if (!Reg)
-          continue;
-        if (MO.isDef()) {
-          Defs.push_back(Reg);
-        } else if (!RedefsByFalse.count(Reg)) {
-          // These are defined before ctrl flow reach the 'false' instructions.
-          // They cannot be modified by the 'true' instructions.
-          for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
-               SubRegs.isValid(); ++SubRegs)
-            ExtUses.insert(*SubRegs);
-        }
-      }
-
-      for (MCPhysReg Reg : Defs) {
-        if (!ExtUses.count(Reg)) {
-          for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
-               SubRegs.isValid(); ++SubRegs)
-            RedefsByFalse.insert(*SubRegs);
-        }
-      }
-    }
-  }
-
-  // Predicate the 'true' block.
-  PredicateBlock(*BBI1, MBB1.end(), *Cond1, &RedefsByFalse);
-
-  // After predicating BBI1, if there is a predicated terminator in BBI1 and
-  // a non-predicated in BBI2, then we don't want to predicate the one from
-  // BBI2. The reason is that if we merged these blocks, we would end up with
-  // two predicated terminators in the same block.
-  // Also, if the branches in MBB1 and MBB2 were non-analyzable, then don't
-  // predicate them either. They were checked to be identical, and so the
-  // same branch would happen regardless of which path was taken.
-  if (!MBB2.empty() && (DI2 == MBB2.end())) {
-    MachineBasicBlock::iterator BBI1T = MBB1.getFirstTerminator();
-    MachineBasicBlock::iterator BBI2T = MBB2.getFirstTerminator();
-    bool BB1Predicated = BBI1T != MBB1.end() && TII->isPredicated(*BBI1T);
-    bool BB2NonPredicated = BBI2T != MBB2.end() && !TII->isPredicated(*BBI2T);
-    if (BB2NonPredicated && (BB1Predicated || !BBI2->IsBrAnalyzable))
-      --DI2;
-  }
-
-  // Predicate the 'false' block.
-  PredicateBlock(*BBI2, DI2, *Cond2);
-
-  // Merge the true block into the entry of the diamond.
-  MergeBlocks(BBI, *BBI1, MergeAddEdges);
-  MergeBlocks(BBI, *BBI2, MergeAddEdges);
-  return true;
-}
-
-/// If convert an almost-diamond sub-CFG where the true
-/// and false blocks share a common tail.
-bool IfConverter::IfConvertForkedDiamond(
-    BBInfo &BBI, IfcvtKind Kind,
-    unsigned NumDups1, unsigned NumDups2,
-    bool TClobbersPred, bool FClobbersPred) {
-  BBInfo &TrueBBI  = BBAnalysis[BBI.TrueBB->getNumber()];
-  BBInfo &FalseBBI = BBAnalysis[BBI.FalseBB->getNumber()];
-
-  // Save the debug location for later.
-  DebugLoc dl;
-  MachineBasicBlock::iterator TIE = TrueBBI.BB->getFirstTerminator();
-  if (TIE != TrueBBI.BB->end())
-    dl = TIE->getDebugLoc();
-  // Removing branches from both blocks is safe, because we have already
-  // determined that both blocks have the same branch instructions. The branch
-  // will be added back at the end, unpredicated.
-  if (!IfConvertDiamondCommon(
-      BBI, TrueBBI, FalseBBI,
-      NumDups1, NumDups2,
-      TClobbersPred, FClobbersPred,
-      /* RemoveBranch */ true, /* MergeAddEdges */ true))
-    return false;
-
-  // Add back the branch.
-  // Debug location saved above when removing the branch from BBI2
-  TII->insertBranch(*BBI.BB, TrueBBI.TrueBB, TrueBBI.FalseBB,
-                    TrueBBI.BrCond, dl);
-
-  // Update block info.
-  BBI.IsDone = TrueBBI.IsDone = FalseBBI.IsDone = true;
-  InvalidatePreds(*BBI.BB);
-
-  // FIXME: Must maintain LiveIns.
-  return true;
-}
-
-/// If convert a diamond sub-CFG.
-bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind,
-                                   unsigned NumDups1, unsigned NumDups2,
-                                   bool TClobbersPred, bool FClobbersPred) {
-  BBInfo &TrueBBI  = BBAnalysis[BBI.TrueBB->getNumber()];
-  BBInfo &FalseBBI = BBAnalysis[BBI.FalseBB->getNumber()];
-  MachineBasicBlock *TailBB = TrueBBI.TrueBB;
-
-  // True block must fall through or end with an unanalyzable terminator.
-  if (!TailBB) {
-    if (blockAlwaysFallThrough(TrueBBI))
-      TailBB = FalseBBI.TrueBB;
-    assert((TailBB || !TrueBBI.IsBrAnalyzable) && "Unexpected!");
-  }
-
-  if (!IfConvertDiamondCommon(
-      BBI, TrueBBI, FalseBBI,
-      NumDups1, NumDups2,
-      TClobbersPred, FClobbersPred,
-      /* RemoveBranch */ TrueBBI.IsBrAnalyzable,
-      /* MergeAddEdges */ TailBB == nullptr))
-    return false;
-
-  // If the if-converted block falls through or unconditionally branches into
-  // the tail block, and the tail block does not have other predecessors, then
-  // fold the tail block in as well. Otherwise, unless it falls through to the
-  // tail, add a unconditional branch to it.
-  if (TailBB) {
-    // We need to remove the edges to the true and false blocks manually since
-    // we didn't let IfConvertDiamondCommon update the CFG.
-    BBI.BB->removeSuccessor(TrueBBI.BB);
-    BBI.BB->removeSuccessor(FalseBBI.BB, true);
-
-    BBInfo &TailBBI = BBAnalysis[TailBB->getNumber()];
-    bool CanMergeTail = !TailBBI.HasFallThrough &&
-      !TailBBI.BB->hasAddressTaken();
-    // The if-converted block can still have a predicated terminator
-    // (e.g. a predicated return). If that is the case, we cannot merge
-    // it with the tail block.
-    MachineBasicBlock::const_iterator TI = BBI.BB->getFirstTerminator();
-    if (TI != BBI.BB->end() && TII->isPredicated(*TI))
-      CanMergeTail = false;
-    // There may still be a fall-through edge from BBI1 or BBI2 to TailBB;
-    // check if there are any other predecessors besides those.
-    unsigned NumPreds = TailBB->pred_size();
-    if (NumPreds > 1)
-      CanMergeTail = false;
-    else if (NumPreds == 1 && CanMergeTail) {
-      MachineBasicBlock::pred_iterator PI = TailBB->pred_begin();
-      if (*PI != TrueBBI.BB && *PI != FalseBBI.BB)
-        CanMergeTail = false;
-    }
-    if (CanMergeTail) {
-      MergeBlocks(BBI, TailBBI);
-      TailBBI.IsDone = true;
-    } else {
-      BBI.BB->addSuccessor(TailBB, BranchProbability::getOne());
-      InsertUncondBranch(*BBI.BB, *TailBB, TII);
-      BBI.HasFallThrough = false;
-    }
-  }
-
-  // Update block info.
-  BBI.IsDone = TrueBBI.IsDone = FalseBBI.IsDone = true;
-  InvalidatePreds(*BBI.BB);
-
-  // FIXME: Must maintain LiveIns.
-  return true;
-}
-
-static bool MaySpeculate(const MachineInstr &MI,
-                         SmallSet<MCPhysReg, 4> &LaterRedefs) {
-  bool SawStore = true;
-  if (!MI.isSafeToMove(nullptr, SawStore))
-    return false;
-
-  for (const MachineOperand &MO : MI.operands()) {
-    if (!MO.isReg())
-      continue;
-    unsigned Reg = MO.getReg();
-    if (!Reg)
-      continue;
-    if (MO.isDef() && !LaterRedefs.count(Reg))
-      return false;
-  }
-
-  return true;
-}
-
-/// Predicate instructions from the start of the block to the specified end with
-/// the specified condition.
-void IfConverter::PredicateBlock(BBInfo &BBI,
-                                 MachineBasicBlock::iterator E,
-                                 SmallVectorImpl<MachineOperand> &Cond,
-                                 SmallSet<MCPhysReg, 4> *LaterRedefs) {
-  bool AnyUnpred = false;
-  bool MaySpec = LaterRedefs != nullptr;
-  for (MachineInstr &I : make_range(BBI.BB->begin(), E)) {
-    if (I.isDebugInstr() || TII->isPredicated(I))
-      continue;
-    // It may be possible not to predicate an instruction if it's the 'true'
-    // side of a diamond and the 'false' side may re-define the instruction's
-    // defs.
-    if (MaySpec && MaySpeculate(I, *LaterRedefs)) {
-      AnyUnpred = true;
-      continue;
-    }
-    // If any instruction is predicated, then every instruction after it must
-    // be predicated.
-    MaySpec = false;
-    if (!TII->PredicateInstruction(I, Cond)) {
-#ifndef NDEBUG
-      dbgs() << "Unable to predicate " << I << "!\n";
-#endif
-      llvm_unreachable(nullptr);
-    }
-
-    // If the predicated instruction now redefines a register as the result of
-    // if-conversion, add an implicit kill.
-    UpdatePredRedefs(I, Redefs);
-  }
-
-  BBI.Predicate.append(Cond.begin(), Cond.end());
-
-  BBI.IsAnalyzed = false;
-  BBI.NonPredSize = 0;
-
-  ++NumIfConvBBs;
-  if (AnyUnpred)
-    ++NumUnpred;
-}
-
-/// Copy and predicate instructions from source BB to the destination block.
-/// Skip end of block branches if IgnoreBr is true.
-void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI,
-                                        SmallVectorImpl<MachineOperand> &Cond,
-                                        bool IgnoreBr) {
-  MachineFunction &MF = *ToBBI.BB->getParent();
-
-  MachineBasicBlock &FromMBB = *FromBBI.BB;
-  for (MachineInstr &I : FromMBB) {
-    // Do not copy the end of the block branches.
-    if (IgnoreBr && I.isBranch())
-      break;
-
-    MachineInstr *MI = MF.CloneMachineInstr(&I);
-    ToBBI.BB->insert(ToBBI.BB->end(), MI);
-    ToBBI.NonPredSize++;
-    unsigned ExtraPredCost = TII->getPredicationCost(I);
-    unsigned NumCycles = SchedModel.computeInstrLatency(&I, false);
-    if (NumCycles > 1)
-      ToBBI.ExtraCost += NumCycles-1;
-    ToBBI.ExtraCost2 += ExtraPredCost;
-
-    if (!TII->isPredicated(I) && !MI->isDebugInstr()) {
-      if (!TII->PredicateInstruction(*MI, Cond)) {
-#ifndef NDEBUG
-        dbgs() << "Unable to predicate " << I << "!\n";
-#endif
-        llvm_unreachable(nullptr);
-      }
-    }
-
-    // If the predicated instruction now redefines a register as the result of
-    // if-conversion, add an implicit kill.
-    UpdatePredRedefs(*MI, Redefs);
-  }
-
-  if (!IgnoreBr) {
-    std::vector<MachineBasicBlock *> Succs(FromMBB.succ_begin(),
-                                           FromMBB.succ_end());
-    MachineBasicBlock *NBB = getNextBlock(FromMBB);
-    MachineBasicBlock *FallThrough = FromBBI.HasFallThrough ? NBB : nullptr;
-
-    for (MachineBasicBlock *Succ : Succs) {
-      // Fallthrough edge can't be transferred.
-      if (Succ == FallThrough)
-        continue;
-      ToBBI.BB->addSuccessor(Succ);
-    }
-  }
-
-  ToBBI.Predicate.append(FromBBI.Predicate.begin(), FromBBI.Predicate.end());
-  ToBBI.Predicate.append(Cond.begin(), Cond.end());
-
-  ToBBI.ClobbersPred |= FromBBI.ClobbersPred;
-  ToBBI.IsAnalyzed = false;
-
-  ++NumDupBBs;
-}
-
-/// Move all instructions from FromBB to the end of ToBB.  This will leave
-/// FromBB as an empty block, so remove all of its successor edges except for
-/// the fall-through edge.  If AddEdges is true, i.e., when FromBBI's branch is
-/// being moved, add those successor edges to ToBBI and remove the old edge
-/// from ToBBI to FromBBI.
-void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges) {
-  MachineBasicBlock &FromMBB = *FromBBI.BB;
-  assert(!FromMBB.hasAddressTaken() &&
-         "Removing a BB whose address is taken!");
-
-  // In case FromMBB contains terminators (e.g. return instruction),
-  // first move the non-terminator instructions, then the terminators.
-  MachineBasicBlock::iterator FromTI = FromMBB.getFirstTerminator();
-  MachineBasicBlock::iterator ToTI = ToBBI.BB->getFirstTerminator();
-  ToBBI.BB->splice(ToTI, &FromMBB, FromMBB.begin(), FromTI);
-
-  // If FromBB has non-predicated terminator we should copy it at the end.
-  if (FromTI != FromMBB.end() && !TII->isPredicated(*FromTI))
-    ToTI = ToBBI.BB->end();
-  ToBBI.BB->splice(ToTI, &FromMBB, FromTI, FromMBB.end());
-
-  // Force normalizing the successors' probabilities of ToBBI.BB to convert all
-  // unknown probabilities into known ones.
-  // FIXME: This usage is too tricky and in the future we would like to
-  // eliminate all unknown probabilities in MBB.
-  if (ToBBI.IsBrAnalyzable)
-    ToBBI.BB->normalizeSuccProbs();
-
-  SmallVector<MachineBasicBlock *, 4> FromSuccs(FromMBB.succ_begin(),
-                                                FromMBB.succ_end());
-  MachineBasicBlock *NBB = getNextBlock(FromMBB);
-  MachineBasicBlock *FallThrough = FromBBI.HasFallThrough ? NBB : nullptr;
-  // The edge probability from ToBBI.BB to FromMBB, which is only needed when
-  // AddEdges is true and FromMBB is a successor of ToBBI.BB.
-  auto To2FromProb = BranchProbability::getZero();
-  if (AddEdges && ToBBI.BB->isSuccessor(&FromMBB)) {
-    // Remove the old edge but remember the edge probability so we can calculate
-    // the correct weights on the new edges being added further down.
-    To2FromProb = MBPI->getEdgeProbability(ToBBI.BB, &FromMBB);
-    ToBBI.BB->removeSuccessor(&FromMBB);
-  }
-
-  for (MachineBasicBlock *Succ : FromSuccs) {
-    // Fallthrough edge can't be transferred.
-    if (Succ == FallThrough)
-      continue;
-
-    auto NewProb = BranchProbability::getZero();
-    if (AddEdges) {
-      // Calculate the edge probability for the edge from ToBBI.BB to Succ,
-      // which is a portion of the edge probability from FromMBB to Succ. The
-      // portion ratio is the edge probability from ToBBI.BB to FromMBB (if
-      // FromBBI is a successor of ToBBI.BB. See comment below for exception).
-      NewProb = MBPI->getEdgeProbability(&FromMBB, Succ);
-
-      // To2FromProb is 0 when FromMBB is not a successor of ToBBI.BB. This
-      // only happens when if-converting a diamond CFG and FromMBB is the
-      // tail BB.  In this case FromMBB post-dominates ToBBI.BB and hence we
-      // could just use the probabilities on FromMBB's out-edges when adding
-      // new successors.
-      if (!To2FromProb.isZero())
-        NewProb *= To2FromProb;
-    }
-
-    FromMBB.removeSuccessor(Succ);
-
-    if (AddEdges) {
-      // If the edge from ToBBI.BB to Succ already exists, update the
-      // probability of this edge by adding NewProb to it. An example is shown
-      // below, in which A is ToBBI.BB and B is FromMBB. In this case we
-      // don't have to set C as A's successor as it already is. We only need to
-      // update the edge probability on A->C. Note that B will not be
-      // immediately removed from A's successors. It is possible that B->D is
-      // not removed either if D is a fallthrough of B. Later the edge A->D
-      // (generated here) and B->D will be combined into one edge. To maintain
-      // correct edge probability of this combined edge, we need to set the edge
-      // probability of A->B to zero, which is already done above. The edge
-      // probability on A->D is calculated by scaling the original probability
-      // on A->B by the probability of B->D.
-      //
-      // Before ifcvt:      After ifcvt (assume B->D is kept):
-      //
-      //       A                A
-      //      /|               /|\
-      //     / B              / B|
-      //    | /|             |  ||
-      //    |/ |             |  |/
-      //    C  D             C  D
-      //
-      if (ToBBI.BB->isSuccessor(Succ))
-        ToBBI.BB->setSuccProbability(
-            find(ToBBI.BB->successors(), Succ),
-            MBPI->getEdgeProbability(ToBBI.BB, Succ) + NewProb);
-      else
-        ToBBI.BB->addSuccessor(Succ, NewProb);
-    }
-  }
-
-  // Move the now empty FromMBB out of the way to the end of the function so
-  // it doesn't interfere with fallthrough checks done by canFallThroughTo().
-  MachineBasicBlock *Last = &*FromMBB.getParent()->rbegin();
-  if (Last != &FromMBB)
-    FromMBB.moveAfter(Last);
-
-  // Normalize the probabilities of ToBBI.BB's successors with all adjustment
-  // we've done above.
-  if (ToBBI.IsBrAnalyzable && FromBBI.IsBrAnalyzable)
-    ToBBI.BB->normalizeSuccProbs();
-
-  ToBBI.Predicate.append(FromBBI.Predicate.begin(), FromBBI.Predicate.end());
-  FromBBI.Predicate.clear();
-
-  ToBBI.NonPredSize += FromBBI.NonPredSize;
-  ToBBI.ExtraCost += FromBBI.ExtraCost;
-  ToBBI.ExtraCost2 += FromBBI.ExtraCost2;
-  FromBBI.NonPredSize = 0;
-  FromBBI.ExtraCost = 0;
-  FromBBI.ExtraCost2 = 0;
-
-  ToBBI.ClobbersPred |= FromBBI.ClobbersPred;
-  ToBBI.HasFallThrough = FromBBI.HasFallThrough;
-  ToBBI.IsAnalyzed = false;
-  FromBBI.IsAnalyzed = false;
-}
-
-FunctionPass *
-llvm::createIfConverter(std::function<bool(const MachineFunction &)> Ftor) {
-  return new IfConverter(std::move(Ftor));
-}