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+//===- llvm/CodeGen/SlotIndexes.h - Slot indexes representation -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements SlotIndex and related classes. The purpose of SlotIndex
+// is to describe a position at which a register can become live, or cease to
+// be live.
+//
+// SlotIndex is mostly a proxy for entries of the SlotIndexList, a class which
+// is held is LiveIntervals and provides the real numbering. This allows
+// LiveIntervals to perform largely transparent renumbering.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_SLOTINDEXES_H
+#define LLVM_CODEGEN_SLOTINDEXES_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/IntervalMap.h"
+#include "llvm/ADT/PointerIntPair.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/ilist.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineInstrBundle.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/Allocator.h"
+#include <algorithm>
+#include <cassert>
+#include <iterator>
+#include <utility>
+
+namespace llvm {
+
+class raw_ostream;
+
+  /// This class represents an entry in the slot index list held in the
+  /// SlotIndexes pass. It should not be used directly. See the
+  /// SlotIndex & SlotIndexes classes for the public interface to this
+  /// information.
+  class IndexListEntry : public ilist_node<IndexListEntry> {
+    MachineInstr *mi;
+    unsigned index;
+
+  public:
+    IndexListEntry(MachineInstr *mi, unsigned index) : mi(mi), index(index) {}
+
+    MachineInstr* getInstr() const { return mi; }
+    void setInstr(MachineInstr *mi) {
+      this->mi = mi;
+    }
+
+    unsigned getIndex() const { return index; }
+    void setIndex(unsigned index) {
+      this->index = index;
+    }
+
+#ifdef EXPENSIVE_CHECKS
+    // When EXPENSIVE_CHECKS is defined, "erased" index list entries will
+    // actually be moved to a "graveyard" list, and have their pointers
+    // poisoned, so that dangling SlotIndex access can be reliably detected.
+    void setPoison() {
+      intptr_t tmp = reinterpret_cast<intptr_t>(mi);
+      assert(((tmp & 0x1) == 0x0) && "Pointer already poisoned?");
+      tmp |= 0x1;
+      mi = reinterpret_cast<MachineInstr*>(tmp);
+    }
+
+    bool isPoisoned() const { return (reinterpret_cast<intptr_t>(mi) & 0x1) == 0x1; }
+#endif // EXPENSIVE_CHECKS
+  };
+
+  template <>
+  struct ilist_alloc_traits<IndexListEntry>
+      : public ilist_noalloc_traits<IndexListEntry> {};
+
+  /// SlotIndex - An opaque wrapper around machine indexes.
+  class SlotIndex {
+    friend class SlotIndexes;
+
+    enum Slot {
+      /// Basic block boundary.  Used for live ranges entering and leaving a
+      /// block without being live in the layout neighbor.  Also used as the
+      /// def slot of PHI-defs.
+      Slot_Block,
+
+      /// Early-clobber register use/def slot.  A live range defined at
+      /// Slot_EarlyClobber interferes with normal live ranges killed at
+      /// Slot_Register.  Also used as the kill slot for live ranges tied to an
+      /// early-clobber def.
+      Slot_EarlyClobber,
+
+      /// Normal register use/def slot.  Normal instructions kill and define
+      /// register live ranges at this slot.
+      Slot_Register,
+
+      /// Dead def kill point.  Kill slot for a live range that is defined by
+      /// the same instruction (Slot_Register or Slot_EarlyClobber), but isn't
+      /// used anywhere.
+      Slot_Dead,
+
+      Slot_Count
+    };
+
+    PointerIntPair<IndexListEntry*, 2, unsigned> lie;
+
+    SlotIndex(IndexListEntry *entry, unsigned slot)
+      : lie(entry, slot) {}
+
+    IndexListEntry* listEntry() const {
+      assert(isValid() && "Attempt to compare reserved index.");
+#ifdef EXPENSIVE_CHECKS
+      assert(!lie.getPointer()->isPoisoned() &&
+             "Attempt to access deleted list-entry.");
+#endif // EXPENSIVE_CHECKS
+      return lie.getPointer();
+    }
+
+    unsigned getIndex() const {
+      return listEntry()->getIndex() | getSlot();
+    }
+
+    /// Returns the slot for this SlotIndex.
+    Slot getSlot() const {
+      return static_cast<Slot>(lie.getInt());
+    }
+
+  public:
+    enum {
+      /// The default distance between instructions as returned by distance().
+      /// This may vary as instructions are inserted and removed.
+      InstrDist = 4 * Slot_Count
+    };
+
+    /// Construct an invalid index.
+    SlotIndex() = default;
+
+    // Construct a new slot index from the given one, and set the slot.
+    SlotIndex(const SlotIndex &li, Slot s) : lie(li.listEntry(), unsigned(s)) {
+      assert(lie.getPointer() != nullptr &&
+             "Attempt to construct index with 0 pointer.");
+    }
+
+    /// Returns true if this is a valid index. Invalid indices do
+    /// not point into an index table, and cannot be compared.
+    bool isValid() const {
+      return lie.getPointer();
+    }
+
+    /// Return true for a valid index.
+    explicit operator bool() const { return isValid(); }
+
+    /// Print this index to the given raw_ostream.
+    void print(raw_ostream &os) const;
+
+    /// Dump this index to stderr.
+    void dump() const;
+
+    /// Compare two SlotIndex objects for equality.
+    bool operator==(SlotIndex other) const {
+      return lie == other.lie;
+    }
+    /// Compare two SlotIndex objects for inequality.
+    bool operator!=(SlotIndex other) const {
+      return lie != other.lie;
+    }
+
+    /// Compare two SlotIndex objects. Return true if the first index
+    /// is strictly lower than the second.
+    bool operator<(SlotIndex other) const {
+      return getIndex() < other.getIndex();
+    }
+    /// Compare two SlotIndex objects. Return true if the first index
+    /// is lower than, or equal to, the second.
+    bool operator<=(SlotIndex other) const {
+      return getIndex() <= other.getIndex();
+    }
+
+    /// Compare two SlotIndex objects. Return true if the first index
+    /// is greater than the second.
+    bool operator>(SlotIndex other) const {
+      return getIndex() > other.getIndex();
+    }
+
+    /// Compare two SlotIndex objects. Return true if the first index
+    /// is greater than, or equal to, the second.
+    bool operator>=(SlotIndex other) const {
+      return getIndex() >= other.getIndex();
+    }
+
+    /// isSameInstr - Return true if A and B refer to the same instruction.
+    static bool isSameInstr(SlotIndex A, SlotIndex B) {
+      return A.lie.getPointer() == B.lie.getPointer();
+    }
+
+    /// isEarlierInstr - Return true if A refers to an instruction earlier than
+    /// B. This is equivalent to A < B && !isSameInstr(A, B).
+    static bool isEarlierInstr(SlotIndex A, SlotIndex B) {
+      return A.listEntry()->getIndex() < B.listEntry()->getIndex();
+    }
+
+    /// Return true if A refers to the same instruction as B or an earlier one.
+    /// This is equivalent to !isEarlierInstr(B, A).
+    static bool isEarlierEqualInstr(SlotIndex A, SlotIndex B) {
+      return !isEarlierInstr(B, A);
+    }
+
+    /// Return the distance from this index to the given one.
+    int distance(SlotIndex other) const {
+      return other.getIndex() - getIndex();
+    }
+
+    /// Return the scaled distance from this index to the given one, where all
+    /// slots on the same instruction have zero distance.
+    int getInstrDistance(SlotIndex other) const {
+      return (other.listEntry()->getIndex() - listEntry()->getIndex())
+        / Slot_Count;
+    }
+
+    /// isBlock - Returns true if this is a block boundary slot.
+    bool isBlock() const { return getSlot() == Slot_Block; }
+
+    /// isEarlyClobber - Returns true if this is an early-clobber slot.
+    bool isEarlyClobber() const { return getSlot() == Slot_EarlyClobber; }
+
+    /// isRegister - Returns true if this is a normal register use/def slot.
+    /// Note that early-clobber slots may also be used for uses and defs.
+    bool isRegister() const { return getSlot() == Slot_Register; }
+
+    /// isDead - Returns true if this is a dead def kill slot.
+    bool isDead() const { return getSlot() == Slot_Dead; }
+
+    /// Returns the base index for associated with this index. The base index
+    /// is the one associated with the Slot_Block slot for the instruction
+    /// pointed to by this index.
+    SlotIndex getBaseIndex() const {
+      return SlotIndex(listEntry(), Slot_Block);
+    }
+
+    /// Returns the boundary index for associated with this index. The boundary
+    /// index is the one associated with the Slot_Block slot for the instruction
+    /// pointed to by this index.
+    SlotIndex getBoundaryIndex() const {
+      return SlotIndex(listEntry(), Slot_Dead);
+    }
+
+    /// Returns the register use/def slot in the current instruction for a
+    /// normal or early-clobber def.
+    SlotIndex getRegSlot(bool EC = false) const {
+      return SlotIndex(listEntry(), EC ? Slot_EarlyClobber : Slot_Register);
+    }
+
+    /// Returns the dead def kill slot for the current instruction.
+    SlotIndex getDeadSlot() const {
+      return SlotIndex(listEntry(), Slot_Dead);
+    }
+
+    /// Returns the next slot in the index list. This could be either the
+    /// next slot for the instruction pointed to by this index or, if this
+    /// index is a STORE, the first slot for the next instruction.
+    /// WARNING: This method is considerably more expensive than the methods
+    /// that return specific slots (getUseIndex(), etc). If you can - please
+    /// use one of those methods.
+    SlotIndex getNextSlot() const {
+      Slot s = getSlot();
+      if (s == Slot_Dead) {
+        return SlotIndex(&*++listEntry()->getIterator(), Slot_Block);
+      }
+      return SlotIndex(listEntry(), s + 1);
+    }
+
+    /// Returns the next index. This is the index corresponding to the this
+    /// index's slot, but for the next instruction.
+    SlotIndex getNextIndex() const {
+      return SlotIndex(&*++listEntry()->getIterator(), getSlot());
+    }
+
+    /// Returns the previous slot in the index list. This could be either the
+    /// previous slot for the instruction pointed to by this index or, if this
+    /// index is a Slot_Block, the last slot for the previous instruction.
+    /// WARNING: This method is considerably more expensive than the methods
+    /// that return specific slots (getUseIndex(), etc). If you can - please
+    /// use one of those methods.
+    SlotIndex getPrevSlot() const {
+      Slot s = getSlot();
+      if (s == Slot_Block) {
+        return SlotIndex(&*--listEntry()->getIterator(), Slot_Dead);
+      }
+      return SlotIndex(listEntry(), s - 1);
+    }
+
+    /// Returns the previous index. This is the index corresponding to this
+    /// index's slot, but for the previous instruction.
+    SlotIndex getPrevIndex() const {
+      return SlotIndex(&*--listEntry()->getIterator(), getSlot());
+    }
+  };
+
+  template <> struct isPodLike<SlotIndex> { static const bool value = true; };
+
+  inline raw_ostream& operator<<(raw_ostream &os, SlotIndex li) {
+    li.print(os);
+    return os;
+  }
+
+  using IdxMBBPair = std::pair<SlotIndex, MachineBasicBlock *>;
+
+  inline bool operator<(SlotIndex V, const IdxMBBPair &IM) {
+    return V < IM.first;
+  }
+
+  inline bool operator<(const IdxMBBPair &IM, SlotIndex V) {
+    return IM.first < V;
+  }
+
+  struct Idx2MBBCompare {
+    bool operator()(const IdxMBBPair &LHS, const IdxMBBPair &RHS) const {
+      return LHS.first < RHS.first;
+    }
+  };
+
+  /// SlotIndexes pass.
+  ///
+  /// This pass assigns indexes to each instruction.
+  class SlotIndexes : public MachineFunctionPass {
+  private:
+    // IndexListEntry allocator.
+    BumpPtrAllocator ileAllocator;
+
+    using IndexList = ilist<IndexListEntry>;
+    IndexList indexList;
+
+#ifdef EXPENSIVE_CHECKS
+    IndexList graveyardList;
+#endif // EXPENSIVE_CHECKS
+
+    MachineFunction *mf;
+
+    using Mi2IndexMap = DenseMap<const MachineInstr *, SlotIndex>;
+    Mi2IndexMap mi2iMap;
+
+    /// MBBRanges - Map MBB number to (start, stop) indexes.
+    SmallVector<std::pair<SlotIndex, SlotIndex>, 8> MBBRanges;
+
+    /// Idx2MBBMap - Sorted list of pairs of index of first instruction
+    /// and MBB id.
+    SmallVector<IdxMBBPair, 8> idx2MBBMap;
+
+    IndexListEntry* createEntry(MachineInstr *mi, unsigned index) {
+      IndexListEntry *entry =
+          static_cast<IndexListEntry *>(ileAllocator.Allocate(
+              sizeof(IndexListEntry), alignof(IndexListEntry)));
+
+      new (entry) IndexListEntry(mi, index);
+
+      return entry;
+    }
+
+    /// Renumber locally after inserting curItr.
+    void renumberIndexes(IndexList::iterator curItr);
+
+  public:
+    static char ID;
+
+    SlotIndexes() : MachineFunctionPass(ID) {
+      initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
+    }
+
+    ~SlotIndexes() override {
+      // The indexList's nodes are all allocated in the BumpPtrAllocator.
+      indexList.clearAndLeakNodesUnsafely();
+    }
+
+    void getAnalysisUsage(AnalysisUsage &au) const override;
+    void releaseMemory() override;
+
+    bool runOnMachineFunction(MachineFunction &fn) override;
+
+    /// Dump the indexes.
+    void dump() const;
+
+    /// Renumber the index list, providing space for new instructions.
+    void renumberIndexes();
+
+    /// Repair indexes after adding and removing instructions.
+    void repairIndexesInRange(MachineBasicBlock *MBB,
+                              MachineBasicBlock::iterator Begin,
+                              MachineBasicBlock::iterator End);
+
+    /// Returns the zero index for this analysis.
+    SlotIndex getZeroIndex() {
+      assert(indexList.front().getIndex() == 0 && "First index is not 0?");
+      return SlotIndex(&indexList.front(), 0);
+    }
+
+    /// Returns the base index of the last slot in this analysis.
+    SlotIndex getLastIndex() {
+      return SlotIndex(&indexList.back(), 0);
+    }
+
+    /// Returns true if the given machine instr is mapped to an index,
+    /// otherwise returns false.
+    bool hasIndex(const MachineInstr &instr) const {
+      return mi2iMap.count(&instr);
+    }
+
+    /// Returns the base index for the given instruction.
+    SlotIndex getInstructionIndex(const MachineInstr &MI) const {
+      // Instructions inside a bundle have the same number as the bundle itself.
+      const MachineInstr &BundleStart = *getBundleStart(MI.getIterator());
+      Mi2IndexMap::const_iterator itr = mi2iMap.find(&BundleStart);
+      assert(itr != mi2iMap.end() && "Instruction not found in maps.");
+      return itr->second;
+    }
+
+    /// Returns the instruction for the given index, or null if the given
+    /// index has no instruction associated with it.
+    MachineInstr* getInstructionFromIndex(SlotIndex index) const {
+      return index.isValid() ? index.listEntry()->getInstr() : nullptr;
+    }
+
+    /// Returns the next non-null index, if one exists.
+    /// Otherwise returns getLastIndex().
+    SlotIndex getNextNonNullIndex(SlotIndex Index) {
+      IndexList::iterator I = Index.listEntry()->getIterator();
+      IndexList::iterator E = indexList.end();
+      while (++I != E)
+        if (I->getInstr())
+          return SlotIndex(&*I, Index.getSlot());
+      // We reached the end of the function.
+      return getLastIndex();
+    }
+
+    /// getIndexBefore - Returns the index of the last indexed instruction
+    /// before MI, or the start index of its basic block.
+    /// MI is not required to have an index.
+    SlotIndex getIndexBefore(const MachineInstr &MI) const {
+      const MachineBasicBlock *MBB = MI.getParent();
+      assert(MBB && "MI must be inserted inna basic block");
+      MachineBasicBlock::const_iterator I = MI, B = MBB->begin();
+      while (true) {
+        if (I == B)
+          return getMBBStartIdx(MBB);
+        --I;
+        Mi2IndexMap::const_iterator MapItr = mi2iMap.find(&*I);
+        if (MapItr != mi2iMap.end())
+          return MapItr->second;
+      }
+    }
+
+    /// getIndexAfter - Returns the index of the first indexed instruction
+    /// after MI, or the end index of its basic block.
+    /// MI is not required to have an index.
+    SlotIndex getIndexAfter(const MachineInstr &MI) const {
+      const MachineBasicBlock *MBB = MI.getParent();
+      assert(MBB && "MI must be inserted inna basic block");
+      MachineBasicBlock::const_iterator I = MI, E = MBB->end();
+      while (true) {
+        ++I;
+        if (I == E)
+          return getMBBEndIdx(MBB);
+        Mi2IndexMap::const_iterator MapItr = mi2iMap.find(&*I);
+        if (MapItr != mi2iMap.end())
+          return MapItr->second;
+      }
+    }
+
+    /// Return the (start,end) range of the given basic block number.
+    const std::pair<SlotIndex, SlotIndex> &
+    getMBBRange(unsigned Num) const {
+      return MBBRanges[Num];
+    }
+
+    /// Return the (start,end) range of the given basic block.
+    const std::pair<SlotIndex, SlotIndex> &
+    getMBBRange(const MachineBasicBlock *MBB) const {
+      return getMBBRange(MBB->getNumber());
+    }
+
+    /// Returns the first index in the given basic block number.
+    SlotIndex getMBBStartIdx(unsigned Num) const {
+      return getMBBRange(Num).first;
+    }
+
+    /// Returns the first index in the given basic block.
+    SlotIndex getMBBStartIdx(const MachineBasicBlock *mbb) const {
+      return getMBBRange(mbb).first;
+    }
+
+    /// Returns the last index in the given basic block number.
+    SlotIndex getMBBEndIdx(unsigned Num) const {
+      return getMBBRange(Num).second;
+    }
+
+    /// Returns the last index in the given basic block.
+    SlotIndex getMBBEndIdx(const MachineBasicBlock *mbb) const {
+      return getMBBRange(mbb).second;
+    }
+
+    /// Iterator over the idx2MBBMap (sorted pairs of slot index of basic block
+    /// begin and basic block)
+    using MBBIndexIterator = SmallVectorImpl<IdxMBBPair>::const_iterator;
+
+    /// Move iterator to the next IdxMBBPair where the SlotIndex is greater or
+    /// equal to \p To.
+    MBBIndexIterator advanceMBBIndex(MBBIndexIterator I, SlotIndex To) const {
+      return std::lower_bound(I, idx2MBBMap.end(), To);
+    }
+
+    /// Get an iterator pointing to the IdxMBBPair with the biggest SlotIndex
+    /// that is greater or equal to \p Idx.
+    MBBIndexIterator findMBBIndex(SlotIndex Idx) const {
+      return advanceMBBIndex(idx2MBBMap.begin(), Idx);
+    }
+
+    /// Returns an iterator for the begin of the idx2MBBMap.
+    MBBIndexIterator MBBIndexBegin() const {
+      return idx2MBBMap.begin();
+    }
+
+    /// Return an iterator for the end of the idx2MBBMap.
+    MBBIndexIterator MBBIndexEnd() const {
+      return idx2MBBMap.end();
+    }
+
+    /// Returns the basic block which the given index falls in.
+    MachineBasicBlock* getMBBFromIndex(SlotIndex index) const {
+      if (MachineInstr *MI = getInstructionFromIndex(index))
+        return MI->getParent();
+
+      MBBIndexIterator I = findMBBIndex(index);
+      // Take the pair containing the index
+      MBBIndexIterator J =
+        ((I != MBBIndexEnd() && I->first > index) ||
+         (I == MBBIndexEnd() && !idx2MBBMap.empty())) ? std::prev(I) : I;
+
+      assert(J != MBBIndexEnd() && J->first <= index &&
+             index < getMBBEndIdx(J->second) &&
+             "index does not correspond to an MBB");
+      return J->second;
+    }
+
+    /// Returns the MBB covering the given range, or null if the range covers
+    /// more than one basic block.
+    MachineBasicBlock* getMBBCoveringRange(SlotIndex start, SlotIndex end) const {
+
+      assert(start < end && "Backwards ranges not allowed.");
+      MBBIndexIterator itr = findMBBIndex(start);
+      if (itr == MBBIndexEnd()) {
+        itr = std::prev(itr);
+        return itr->second;
+      }
+
+      // Check that we don't cross the boundary into this block.
+      if (itr->first < end)
+        return nullptr;
+
+      itr = std::prev(itr);
+
+      if (itr->first <= start)
+        return itr->second;
+
+      return nullptr;
+    }
+
+    /// Insert the given machine instruction into the mapping. Returns the
+    /// assigned index.
+    /// If Late is set and there are null indexes between mi's neighboring
+    /// instructions, create the new index after the null indexes instead of
+    /// before them.
+    SlotIndex insertMachineInstrInMaps(MachineInstr &MI, bool Late = false) {
+      assert(!MI.isInsideBundle() &&
+             "Instructions inside bundles should use bundle start's slot.");
+      assert(mi2iMap.find(&MI) == mi2iMap.end() && "Instr already indexed.");
+      // Numbering DBG_VALUE instructions could cause code generation to be
+      // affected by debug information.
+      assert(!MI.isDebugValue() && "Cannot number DBG_VALUE instructions.");
+
+      assert(MI.getParent() != nullptr && "Instr must be added to function.");
+
+      // Get the entries where MI should be inserted.
+      IndexList::iterator prevItr, nextItr;
+      if (Late) {
+        // Insert MI's index immediately before the following instruction.
+        nextItr = getIndexAfter(MI).listEntry()->getIterator();
+        prevItr = std::prev(nextItr);
+      } else {
+        // Insert MI's index immediately after the preceding instruction.
+        prevItr = getIndexBefore(MI).listEntry()->getIterator();
+        nextItr = std::next(prevItr);
+      }
+
+      // Get a number for the new instr, or 0 if there's no room currently.
+      // In the latter case we'll force a renumber later.
+      unsigned dist = ((nextItr->getIndex() - prevItr->getIndex())/2) & ~3u;
+      unsigned newNumber = prevItr->getIndex() + dist;
+
+      // Insert a new list entry for MI.
+      IndexList::iterator newItr =
+          indexList.insert(nextItr, createEntry(&MI, newNumber));
+
+      // Renumber locally if we need to.
+      if (dist == 0)
+        renumberIndexes(newItr);
+
+      SlotIndex newIndex(&*newItr, SlotIndex::Slot_Block);
+      mi2iMap.insert(std::make_pair(&MI, newIndex));
+      return newIndex;
+    }
+
+    /// Removes machine instruction (bundle) \p MI from the mapping.
+    /// This should be called before MachineInstr::eraseFromParent() is used to
+    /// remove a whole bundle or an unbundled instruction.
+    void removeMachineInstrFromMaps(MachineInstr &MI);
+
+    /// Removes a single machine instruction \p MI from the mapping.
+    /// This should be called before MachineInstr::eraseFromBundle() is used to
+    /// remove a single instruction (out of a bundle).
+    void removeSingleMachineInstrFromMaps(MachineInstr &MI);
+
+    /// ReplaceMachineInstrInMaps - Replacing a machine instr with a new one in
+    /// maps used by register allocator. \returns the index where the new
+    /// instruction was inserted.
+    SlotIndex replaceMachineInstrInMaps(MachineInstr &MI, MachineInstr &NewMI) {
+      Mi2IndexMap::iterator mi2iItr = mi2iMap.find(&MI);
+      if (mi2iItr == mi2iMap.end())
+        return SlotIndex();
+      SlotIndex replaceBaseIndex = mi2iItr->second;
+      IndexListEntry *miEntry(replaceBaseIndex.listEntry());
+      assert(miEntry->getInstr() == &MI &&
+             "Mismatched instruction in index tables.");
+      miEntry->setInstr(&NewMI);
+      mi2iMap.erase(mi2iItr);
+      mi2iMap.insert(std::make_pair(&NewMI, replaceBaseIndex));
+      return replaceBaseIndex;
+    }
+
+    /// Add the given MachineBasicBlock into the maps.
+    void insertMBBInMaps(MachineBasicBlock *mbb) {
+      MachineFunction::iterator nextMBB =
+        std::next(MachineFunction::iterator(mbb));
+
+      IndexListEntry *startEntry = nullptr;
+      IndexListEntry *endEntry = nullptr;
+      IndexList::iterator newItr;
+      if (nextMBB == mbb->getParent()->end()) {
+        startEntry = &indexList.back();
+        endEntry = createEntry(nullptr, 0);
+        newItr = indexList.insertAfter(startEntry->getIterator(), endEntry);
+      } else {
+        startEntry = createEntry(nullptr, 0);
+        endEntry = getMBBStartIdx(&*nextMBB).listEntry();
+        newItr = indexList.insert(endEntry->getIterator(), startEntry);
+      }
+
+      SlotIndex startIdx(startEntry, SlotIndex::Slot_Block);
+      SlotIndex endIdx(endEntry, SlotIndex::Slot_Block);
+
+      MachineFunction::iterator prevMBB(mbb);
+      assert(prevMBB != mbb->getParent()->end() &&
+             "Can't insert a new block at the beginning of a function.");
+      --prevMBB;
+      MBBRanges[prevMBB->getNumber()].second = startIdx;
+
+      assert(unsigned(mbb->getNumber()) == MBBRanges.size() &&
+             "Blocks must be added in order");
+      MBBRanges.push_back(std::make_pair(startIdx, endIdx));
+      idx2MBBMap.push_back(IdxMBBPair(startIdx, mbb));
+
+      renumberIndexes(newItr);
+      std::sort(idx2MBBMap.begin(), idx2MBBMap.end(), Idx2MBBCompare());
+    }
+
+    /// \brief Free the resources that were required to maintain a SlotIndex.
+    ///
+    /// Once an index is no longer needed (for instance because the instruction
+    /// at that index has been moved), the resources required to maintain the
+    /// index can be relinquished to reduce memory use and improve renumbering
+    /// performance. Any remaining SlotIndex objects that point to the same
+    /// index are left 'dangling' (much the same as a dangling pointer to a
+    /// freed object) and should not be accessed, except to destruct them.
+    ///
+    /// Like dangling pointers, access to dangling SlotIndexes can cause
+    /// painful-to-track-down bugs, especially if the memory for the index
+    /// previously pointed to has been re-used. To detect dangling SlotIndex
+    /// bugs, build with EXPENSIVE_CHECKS=1. This will cause "erased" indexes to
+    /// be retained in a graveyard instead of being freed. Operations on indexes
+    /// in the graveyard will trigger an assertion.
+    void eraseIndex(SlotIndex index) {
+      IndexListEntry *entry = index.listEntry();
+#ifdef EXPENSIVE_CHECKS
+      indexList.remove(entry);
+      graveyardList.push_back(entry);
+      entry->setPoison();
+#else
+      indexList.erase(entry);
+#endif
+    }
+  };
+
+  // Specialize IntervalMapInfo for half-open slot index intervals.
+  template <>
+  struct IntervalMapInfo<SlotIndex> : IntervalMapHalfOpenInfo<SlotIndex> {
+  };
+
+} // end namespace llvm
+
+#endif // LLVM_CODEGEN_SLOTINDEXES_H