Represent RegUnit liveness with LiveRange instance

Previously LiveInterval has been used, but having a spill weight and
register number is unnecessary for a register unit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192397 91177308-0d34-0410-b5e6-96231b3b80d8

13 files changed, 132 insertions, 129 deletions

diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index 922c2a09df..d8437f09aa 100644
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -90,9 +90,9 @@ namespace llvm {
     /// block.
     SmallVector<std::pair<unsigned, unsigned>, 8> RegMaskBlocks;
 
-    /// RegUnitIntervals - Keep a live interval for each register unit as a way
-    /// of tracking fixed physreg interference.
-    SmallVector<LiveInterval*, 0> RegUnitIntervals;
+    /// Keeps a live range set for each register unit to track fixed physreg
+    /// interference.
+    SmallVector<LiveRange*, 0> RegUnitRanges;
 
   public:
     static char ID; // Pass identification, replacement for typeid
@@ -364,24 +364,24 @@ namespace llvm {
 
     /// getRegUnit - Return the live range for Unit.
     /// It will be computed if it doesn't exist.
-    LiveInterval &getRegUnit(unsigned Unit) {
-      LiveInterval *LI = RegUnitIntervals[Unit];
-      if (!LI) {
+    LiveRange &getRegUnit(unsigned Unit) {
+      LiveRange *LR = RegUnitRanges[Unit];
+      if (!LR) {
         // Compute missing ranges on demand.
-        RegUnitIntervals[Unit] = LI = new LiveInterval(Unit, HUGE_VALF);
-        computeRegUnitInterval(*LI);
+        RegUnitRanges[Unit] = LR = new LiveRange();
+        computeRegUnitRange(*LR, Unit);
       }
-      return *LI;
+      return *LR;
     }
 
     /// getCachedRegUnit - Return the live range for Unit if it has already
     /// been computed, or NULL if it hasn't been computed yet.
-    LiveInterval *getCachedRegUnit(unsigned Unit) {
-      return RegUnitIntervals[Unit];
+    LiveRange *getCachedRegUnit(unsigned Unit) {
+      return RegUnitRanges[Unit];
     }
 
-    const LiveInterval *getCachedRegUnit(unsigned Unit) const {
-      return RegUnitIntervals[Unit];
+    const LiveRange *getCachedRegUnit(unsigned Unit) const {
+      return RegUnitRanges[Unit];
     }
 
   private:
@@ -397,7 +397,7 @@ namespace llvm {
     void dumpInstrs() const;
 
     void computeLiveInRegUnits();
-    void computeRegUnitInterval(LiveInterval&);
+    void computeRegUnitRange(LiveRange&, unsigned Unit);
     void computeVirtRegInterval(LiveInterval&);
 
     class HMEditor;
diff --git a/include/llvm/CodeGen/RegisterPressure.h b/include/llvm/CodeGen/RegisterPressure.h
index 1db0b9f9b0..a801d1d1ee 100644
--- a/include/llvm/CodeGen/RegisterPressure.h
+++ b/include/llvm/CodeGen/RegisterPressure.h
@@ -22,7 +22,7 @@
 namespace llvm {
 
 class LiveIntervals;
-class LiveInterval;
+class LiveRange;
 class RegisterClassInfo;
 class MachineInstr;
 
@@ -424,7 +424,7 @@ public:
   void dump() const;
 
 protected:
-  const LiveInterval *getInterval(unsigned Reg) const;
+  const LiveRange *getLiveRange(unsigned Reg) const;
 
   void increaseRegPressure(ArrayRef<unsigned> Regs);
   void decreaseRegPressure(ArrayRef<unsigned> Regs);
diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp
index 85bf4efa77..0af7664417 100644
--- a/lib/CodeGen/InlineSpiller.cpp
+++ b/lib/CodeGen/InlineSpiller.cpp
@@ -1106,10 +1106,10 @@ foldMemoryOperand(ArrayRef<std::pair<MachineInstr*, unsigned> > Ops,
     // FoldMI does not define this physreg. Remove the LI segment.
     assert(MO->isDead() && "Cannot fold physreg def");
     for (MCRegUnitIterator Units(Reg, &TRI); Units.isValid(); ++Units) {
-      if (LiveInterval *LI = LIS.getCachedRegUnit(*Units)) {
+      if (LiveRange *LR = LIS.getCachedRegUnit(*Units)) {
         SlotIndex Idx = LIS.getInstructionIndex(MI).getRegSlot();
-        if (VNInfo *VNI = LI->getVNInfoAt(Idx))
-          LI->removeValNo(VNI);
+        if (VNInfo *VNI = LR->getVNInfoAt(Idx))
+          LR->removeValNo(VNI);
       }
     }
   }
diff --git a/lib/CodeGen/InterferenceCache.cpp b/lib/CodeGen/InterferenceCache.cpp
index a8e711e33b..427225dbdc 100644
--- a/lib/CodeGen/InterferenceCache.cpp
+++ b/lib/CodeGen/InterferenceCache.cpp
@@ -204,11 +204,11 @@ void InterferenceCache::Entry::update(unsigned MBBNum) {
   // Fixed interference.
   for (unsigned i = 0, e = RegUnits.size(); i != e; ++i) {
     LiveInterval::iterator &I = RegUnits[i].FixedI;
-    LiveInterval *LI = RegUnits[i].Fixed;
-    if (I == LI->end() || I->start >= Stop)
+    LiveRange *LR = RegUnits[i].Fixed;
+    if (I == LR->end() || I->start >= Stop)
       continue;
-    I = LI->advanceTo(I, Stop);
-    bool Backup = I == LI->end() || I->start >= Stop;
+    I = LR->advanceTo(I, Stop);
+    bool Backup = I == LR->end() || I->start >= Stop;
     if (Backup)
       --I;
     SlotIndex StopI = I->end;
diff --git a/lib/CodeGen/InterferenceCache.h b/lib/CodeGen/InterferenceCache.h
index c02fb9a1ee..800f705575 100644
--- a/lib/CodeGen/InterferenceCache.h
+++ b/lib/CodeGen/InterferenceCache.h
@@ -72,7 +72,7 @@ class InterferenceCache {
       unsigned VirtTag;
 
       /// Fixed interference in RegUnit.
-      LiveInterval *Fixed;
+      LiveRange *Fixed;
 
       /// Iterator pointing into the fixed RegUnit interference.
       LiveInterval::iterator FixedI;
diff --git a/lib/CodeGen/LiveDebugVariables.cpp b/lib/CodeGen/LiveDebugVariables.cpp
index c1f6fd57de..25645e088e 100644
--- a/lib/CodeGen/LiveDebugVariables.cpp
+++ b/lib/CodeGen/LiveDebugVariables.cpp
@@ -220,13 +220,13 @@ public:
   /// End points where VNI is no longer live are added to Kills.
   /// @param Idx   Starting point for the definition.
   /// @param LocNo Location number to propagate.
-  /// @param LI    Restrict liveness to where LI has the value VNI. May be null.
-  /// @param VNI   When LI is not null, this is the value to restrict to.
+  /// @param LR    Restrict liveness to where LR has the value VNI. May be null.
+  /// @param VNI   When LR is not null, this is the value to restrict to.
   /// @param Kills Append end points of VNI's live range to Kills.
   /// @param LIS   Live intervals analysis.
   /// @param MDT   Dominator tree.
   void extendDef(SlotIndex Idx, unsigned LocNo,
-                 LiveInterval *LI, const VNInfo *VNI,
+                 LiveRange *LR, const VNInfo *VNI,
                  SmallVectorImpl<SlotIndex> *Kills,
                  LiveIntervals &LIS, MachineDominatorTree &MDT,
                  UserValueScopes &UVS);
@@ -495,7 +495,7 @@ bool LDVImpl::collectDebugValues(MachineFunction &mf) {
 }
 
 void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
-                          LiveInterval *LI, const VNInfo *VNI,
+                          LiveRange *LR, const VNInfo *VNI,
                           SmallVectorImpl<SlotIndex> *Kills,
                           LiveIntervals &LIS, MachineDominatorTree &MDT,
                           UserValueScopes &UVS) {
@@ -509,8 +509,8 @@ void UserValue::extendDef(SlotIndex Idx, unsigned LocNo,
 
     // Limit to VNI's live range.
     bool ToEnd = true;
-    if (LI && VNI) {
-      LiveInterval::Segment *Segment = LI->getSegmentContaining(Start);
+    if (LR && VNI) {
+      LiveInterval::Segment *Segment = LR->getSegmentContaining(Start);
       if (!Segment || Segment->valno != VNI) {
         if (Kills)
           Kills->push_back(Start);
@@ -669,10 +669,10 @@ UserValue::computeIntervals(MachineRegisterInfo &MRI,
 
     // For physregs, use the live range of the first regunit as a guide.
     unsigned Unit = *MCRegUnitIterator(Loc.getReg(), &TRI);
-    LiveInterval *LI = &LIS.getRegUnit(Unit);
-    const VNInfo *VNI = LI->getVNInfoAt(Idx);
+    LiveRange *LR = &LIS.getRegUnit(Unit);
+    const VNInfo *VNI = LR->getVNInfoAt(Idx);
     // Don't track copies from physregs, it is too expensive.
-    extendDef(Idx, LocNo, LI, VNI, 0, LIS, MDT, UVS);
+    extendDef(Idx, LocNo, LR, VNI, 0, LIS, MDT, UVS);
   }
 
   // Finally, erase all the undefs.
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 18abe41174..017c1bc39c 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -95,9 +95,9 @@ void LiveIntervals::releaseMemory() {
   RegMaskBits.clear();
   RegMaskBlocks.clear();
 
-  for (unsigned i = 0, e = RegUnitIntervals.size(); i != e; ++i)
-    delete RegUnitIntervals[i];
-  RegUnitIntervals.clear();
+  for (unsigned i = 0, e = RegUnitRanges.size(); i != e; ++i)
+    delete RegUnitRanges[i];
+  RegUnitRanges.clear();
 
   // Release VNInfo memory regions, VNInfo objects don't need to be dtor'd.
   VNInfoAllocator.Reset();
@@ -139,9 +139,9 @@ void LiveIntervals::print(raw_ostream &OS, const Module* ) const {
   OS << "********** INTERVALS **********\n";
 
   // Dump the regunits.
-  for (unsigned i = 0, e = RegUnitIntervals.size(); i != e; ++i)
-    if (LiveInterval *LI = RegUnitIntervals[i])
-      OS << PrintRegUnit(i, TRI) << " = " << *LI << '\n';
+  for (unsigned i = 0, e = RegUnitRanges.size(); i != e; ++i)
+    if (LiveRange *LR = RegUnitRanges[i])
+      OS << PrintRegUnit(i, TRI) << " = " << *LR << '\n';
 
   // Dump the virtregs.
   for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
@@ -227,12 +227,10 @@ void LiveIntervals::computeRegMasks() {
 // interference.
 //
 
-/// computeRegUnitInterval - Compute the live interval of a register unit, based
-/// on the uses and defs of aliasing registers.  The interval should be empty,
+/// computeRegUnitInterval - Compute the live range of a register unit, based
+/// on the uses and defs of aliasing registers.  The range should be empty,
 /// or contain only dead phi-defs from ABI blocks.
-void LiveIntervals::computeRegUnitInterval(LiveInterval &LI) {
-  unsigned Unit = LI.reg;
-
+void LiveIntervals::computeRegUnitRange(LiveRange &LR, unsigned Unit) {
   assert(LRCalc && "LRCalc not initialized.");
   LRCalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator());
 
@@ -245,18 +243,18 @@ void LiveIntervals::computeRegUnitInterval(LiveInterval &LI) {
     for (MCSuperRegIterator Supers(*Roots, TRI, /*IncludeSelf=*/true);
          Supers.isValid(); ++Supers) {
       if (!MRI->reg_empty(*Supers))
-        LRCalc->createDeadDefs(LI, *Supers);
+        LRCalc->createDeadDefs(LR, *Supers);
     }
   }
 
-  // Now extend LI to reach all uses.
+  // Now extend LR to reach all uses.
   // Ignore uses of reserved registers. We only track defs of those.
   for (MCRegUnitRootIterator Roots(Unit, TRI); Roots.isValid(); ++Roots) {
     for (MCSuperRegIterator Supers(*Roots, TRI, /*IncludeSelf=*/true);
          Supers.isValid(); ++Supers) {
       unsigned Reg = *Supers;
       if (!MRI->isReserved(Reg) && !MRI->reg_empty(Reg))
-        LRCalc->extendToUses(LI, Reg);
+        LRCalc->extendToUses(LR, Reg);
     }
   }
 }
@@ -267,11 +265,11 @@ void LiveIntervals::computeRegUnitInterval(LiveInterval &LI) {
 /// without a corresponding def when entering the entry block or a landing pad.
 ///
 void LiveIntervals::computeLiveInRegUnits() {
-  RegUnitIntervals.resize(TRI->getNumRegUnits());
+  RegUnitRanges.resize(TRI->getNumRegUnits());
   DEBUG(dbgs() << "Computing live-in reg-units in ABI blocks.\n");
 
-  // Keep track of the intervals allocated.
-  SmallVector<LiveInterval*, 8> NewIntvs;
+  // Keep track of the live range sets allocated.
+  SmallVector<unsigned, 8> NewRanges;
 
   // Check all basic blocks for live-ins.
   for (MachineFunction::const_iterator MFI = MF->begin(), MFE = MF->end();
@@ -289,23 +287,25 @@ void LiveIntervals::computeLiveInRegUnits() {
          LIE = MBB->livein_end(); LII != LIE; ++LII) {
       for (MCRegUnitIterator Units(*LII, TRI); Units.isValid(); ++Units) {
         unsigned Unit = *Units;
-        LiveInterval *Intv = RegUnitIntervals[Unit];
-        if (!Intv) {
-          Intv = RegUnitIntervals[Unit] = new LiveInterval(Unit, HUGE_VALF);
-          NewIntvs.push_back(Intv);
+        LiveRange *LR = RegUnitRanges[Unit];
+        if (!LR) {
+          LR = RegUnitRanges[Unit] = new LiveRange();
+          NewRanges.push_back(Unit);
         }
-        VNInfo *VNI = Intv->createDeadDef(Begin, getVNInfoAllocator());
+        VNInfo *VNI = LR->createDeadDef(Begin, getVNInfoAllocator());
         (void)VNI;
         DEBUG(dbgs() << ' ' << PrintRegUnit(Unit, TRI) << '#' << VNI->id);
       }
     }
     DEBUG(dbgs() << '\n');
   }
-  DEBUG(dbgs() << "Created " << NewIntvs.size() << " new intervals.\n");
+  DEBUG(dbgs() << "Created " << NewRanges.size() << " new intervals.\n");
 
-  // Compute the 'normal' part of the intervals.
-  for (unsigned i = 0, e = NewIntvs.size(); i != e; ++i)
-    computeRegUnitInterval(*NewIntvs[i]);
+  // Compute the 'normal' part of the ranges.
+  for (unsigned i = 0, e = NewRanges.size(); i != e; ++i) {
+    unsigned Unit = NewRanges[i];
+    computeRegUnitRange(*RegUnitRanges[Unit], Unit);
+  }
 }
 
 
@@ -514,7 +514,7 @@ void LiveIntervals::pruneValue(LiveInterval *LI, SlotIndex Kill,
 
 void LiveIntervals::addKillFlags(const VirtRegMap *VRM) {
   // Keep track of regunit ranges.
-  SmallVector<std::pair<LiveInterval*, LiveInterval::iterator>, 8> RU;
+  SmallVector<std::pair<LiveRange*, LiveRange::iterator>, 8> RU;
 
   for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
     unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
@@ -529,10 +529,10 @@ void LiveIntervals::addKillFlags(const VirtRegMap *VRM) {
     RU.clear();
     for (MCRegUnitIterator Units(VRM->getPhys(Reg), TRI); Units.isValid();
          ++Units) {
-      LiveInterval *RUInt = &getRegUnit(*Units);
-      if (RUInt->empty())
+      LiveRange &RURanges = getRegUnit(*Units);
+      if (RURanges.empty())
         continue;
-      RU.push_back(std::make_pair(RUInt, RUInt->find(LI->begin()->end)));
+      RU.push_back(std::make_pair(&RURanges, RURanges.find(LI->begin()->end)));
     }
 
     // Every instruction that kills Reg corresponds to a segment range end
@@ -556,12 +556,12 @@ void LiveIntervals::addKillFlags(const VirtRegMap *VRM) {
       // There should be no kill flag on FOO when %vreg5 is rewritten as %EAX.
       bool CancelKill = false;
       for (unsigned u = 0, e = RU.size(); u != e; ++u) {
-        LiveInterval *RInt = RU[u].first;
-        LiveInterval::iterator &I = RU[u].second;
-        if (I == RInt->end())
+        LiveRange &RRanges = *RU[u].first;
+        LiveRange::iterator &I = RU[u].second;
+        if (I == RRanges.end())
           continue;
-        I = RInt->advanceTo(I, RI->end);
-        if (I == RInt->end() || I->start >= RI->end)
+        I = RRanges.advanceTo(I, RI->end);
+        if (I == RRanges.end() || I->start >= RI->end)
           continue;
         // I is overlapping RI.
         CancelKill = true;
@@ -710,7 +710,7 @@ private:
   const TargetRegisterInfo& TRI;
   SlotIndex OldIdx;
   SlotIndex NewIdx;
-  SmallPtrSet<LiveInterval*, 8> Updated;
+  SmallPtrSet<LiveRange*, 8> Updated;
   bool UpdateFlags;
 
 public:
@@ -724,7 +724,7 @@ public:
   // physregs, even those that aren't needed for regalloc, in order to update
   // kill flags. This is wasteful. Eventually, LiveVariables will strip all kill
   // flags, and postRA passes will use a live register utility instead.
-  LiveInterval *getRegUnitLI(unsigned Unit) {
+  LiveRange *getRegUnitLI(unsigned Unit) {
     if (UpdateFlags)
       return &LIS.getRegUnit(Unit);
     return LIS.getCachedRegUnit(Unit);
@@ -749,15 +749,16 @@ public:
       if (!Reg)
         continue;
       if (TargetRegisterInfo::isVirtualRegister(Reg)) {
-        updateRange(LIS.getInterval(Reg));
+        LiveInterval &LI = LIS.getInterval(Reg);
+        updateRange(LI, Reg);
         continue;
       }
 
       // For physregs, only update the regunits that actually have a
       // precomputed live range.
       for (MCRegUnitIterator Units(Reg, &TRI); Units.isValid(); ++Units)
-        if (LiveInterval *LI = getRegUnitLI(*Units))
-          updateRange(*LI);
+        if (LiveRange *LR = getRegUnitLI(*Units))
+          updateRange(*LR, *Units);
     }
     if (hasRegMask)
       updateRegMaskSlots();
@@ -766,26 +767,26 @@ public:
 private:
   /// Update a single live range, assuming an instruction has been moved from
   /// OldIdx to NewIdx.
-  void updateRange(LiveInterval &LI) {
-    if (!Updated.insert(&LI))
+  void updateRange(LiveRange &LR, unsigned Reg) {
+    if (!Updated.insert(&LR))
       return;
     DEBUG({
       dbgs() << "     ";
-      if (TargetRegisterInfo::isVirtualRegister(LI.reg))
-        dbgs() << PrintReg(LI.reg);
+      if (TargetRegisterInfo::isVirtualRegister(Reg))
+        dbgs() << PrintReg(Reg);
       else
-        dbgs() << PrintRegUnit(LI.reg, &TRI);
-      dbgs() << ":\t" << LI << '\n';
+        dbgs() << PrintRegUnit(Reg, &TRI);
+      dbgs() << ":\t" << LR << '\n';
     });
     if (SlotIndex::isEarlierInstr(OldIdx, NewIdx))
-      handleMoveDown(LI);
+      handleMoveDown(LR);
     else
-      handleMoveUp(LI);
-    DEBUG(dbgs() << "        -->\t" << LI << '\n');
-    LI.verify();
+      handleMoveUp(LR, Reg);
+    DEBUG(dbgs() << "        -->\t" << LR << '\n');
+    LR.verify();
   }
 
-  /// Update LI to reflect an instruction has been moved downwards from OldIdx
+  /// Update LR to reflect an instruction has been moved downwards from OldIdx
   /// to NewIdx.
   ///
   /// 1. Live def at OldIdx:
@@ -805,11 +806,11 @@ private:
   /// 5. Value read at OldIdx, killed before NewIdx:
   ///    Extend kill to NewIdx.
   ///
-  void handleMoveDown(LiveInterval &LI) {
+  void handleMoveDown(LiveRange &LR) {
     // First look for a kill at OldIdx.
-    LiveInterval::iterator I = LI.find(OldIdx.getBaseIndex());
-    LiveInterval::iterator E = LI.end();
-    // Is LI even live at OldIdx?
+    LiveRange::iterator I = LR.find(OldIdx.getBaseIndex());
+    LiveRange::iterator E = LR.end();
+    // Is LR even live at OldIdx?
     if (I == E || SlotIndex::isEarlierInstr(OldIdx, I->start))
       return;
 
@@ -826,7 +827,7 @@ private:
         for (MIBundleOperands MO(KillMI); MO.isValid(); ++MO)
           if (MO->isReg() && MO->isUse())
             MO->setIsKill(false);
-      // Adjust I->end to reach NewIdx. This may temporarily make LI invalid by
+      // Adjust I->end to reach NewIdx. This may temporarily make LR invalid by
       // overlapping ranges. Case 5 above.
       I->end = NewIdx.getRegSlot(I->end.isEarlyClobber());
       // If this was a kill, there may also be a def. Otherwise we're done.
@@ -855,16 +856,16 @@ private:
     assert((I->end == OldIdx.getDeadSlot() ||
             SlotIndex::isSameInstr(I->end, NewIdx)) &&
             "Cannot move def below kill");
-    LiveInterval::iterator NewI = LI.advanceTo(I, NewIdx.getRegSlot());
+    LiveRange::iterator NewI = LR.advanceTo(I, NewIdx.getRegSlot());
     if (NewI != E && SlotIndex::isSameInstr(NewI->start, NewIdx)) {
       // There is an existing def at NewIdx, case 4 above. The def at OldIdx is
       // coalesced into that value.
       assert(NewI->valno != DefVNI && "Multiple defs of value?");
-      LI.removeValNo(DefVNI);
+      LR.removeValNo(DefVNI);
       return;
     }
     // There was no existing def at NewIdx. Turn *I into a dead def at NewIdx.
-    // If the def at OldIdx was dead, we allow it to be moved across other LI
+    // If the def at OldIdx was dead, we allow it to be moved across other LR
     // values. The new range should be placed immediately before NewI, move any
     // intermediate ranges up.
     assert(NewI != I && "Inconsistent iterators");
@@ -873,7 +874,7 @@ private:
       = LiveRange::Segment(DefVNI->def, NewIdx.getDeadSlot(), DefVNI);
   }
 
-  /// Update LI to reflect an instruction has been moved upwards from OldIdx
+  /// Update LR to reflect an instruction has been moved upwards from OldIdx
   /// to NewIdx.
   ///
   /// 1. Live def at OldIdx:
@@ -893,11 +894,11 @@ private:
   ///    Hoist kill to NewIdx, then scan for last kill between NewIdx and
   ///    OldIdx.
   ///
-  void handleMoveUp(LiveInterval &LI) {
+  void handleMoveUp(LiveRange &LR, unsigned Reg) {
     // First look for a kill at OldIdx.
-    LiveInterval::iterator I = LI.find(OldIdx.getBaseIndex());
-    LiveInterval::iterator E = LI.end();
-    // Is LI even live at OldIdx?
+    LiveRange::iterator I = LR.find(OldIdx.getBaseIndex());
+    LiveRange::iterator E = LR.end();
+    // Is LR even live at OldIdx?
     if (I == E || SlotIndex::isEarlierInstr(OldIdx, I->start))
       return;
 
@@ -914,7 +915,7 @@ private:
       if (I == E || !SlotIndex::isSameInstr(I->start, OldIdx)) {
         // No def, search for the new kill.
         // This can never be an early clobber kill since there is no def.
-        llvm::prior(I)->end = findLastUseBefore(LI.reg).getRegSlot();
+        llvm::prior(I)->end = findLastUseBefore(Reg).getRegSlot();
         return;
       }
     }
@@ -926,18 +927,18 @@ private:
     DefVNI->def = NewIdx.getRegSlot(I->start.isEarlyClobber());
 
     // Check for an existing def at NewIdx.
-    LiveInterval::iterator NewI = LI.find(NewIdx.getRegSlot());
+    LiveRange::iterator NewI = LR.find(NewIdx.getRegSlot());
     if (SlotIndex::isSameInstr(NewI->start, NewIdx)) {
       assert(NewI->valno != DefVNI && "Same value defined more than once?");
       // There is an existing def at NewIdx.
       if (I->end.isDead()) {
         // Case 3: Remove the dead def at OldIdx.
-        LI.removeValNo(DefVNI);
+        LR.removeValNo(DefVNI);
         return;
       }
       // Case 4: Replace def at NewIdx with live def at OldIdx.
       I->start = DefVNI->def;
-      LI.removeValNo(NewI->valno);
+      LR.removeValNo(NewI->valno);
       return;
     }
 
@@ -948,7 +949,7 @@ private:
       return;
     }
 
-    // DefVNI is a dead def. It may have been moved across other values in LI,
+    // DefVNI is a dead def. It may have been moved across other values in LR,
     // so move I up to NewI. Slide [NewI;I) down one position.
     std::copy_backward(NewI, I, llvm::next(I));
     *NewI = LiveRange::Segment(DefVNI->def, NewIdx.getDeadSlot(), DefVNI);
diff --git a/lib/CodeGen/LiveRangeEdit.cpp b/lib/CodeGen/LiveRangeEdit.cpp
index d5990ef248..09b0cede91 100644
--- a/lib/CodeGen/LiveRangeEdit.cpp
+++ b/lib/CodeGen/LiveRangeEdit.cpp
@@ -262,9 +262,9 @@ void LiveRangeEdit::eliminateDeadDef(MachineInstr *MI, ToShrinkSet &ToShrink) {
       else if (MOI->isDef()) {
         for (MCRegUnitIterator Units(Reg, MRI.getTargetRegisterInfo());
              Units.isValid(); ++Units) {
-          if (LiveInterval *LI = LIS.getCachedRegUnit(*Units)) {
-            if (VNInfo *VNI = LI->getVNInfoAt(Idx))
-              LI->removeValNo(VNI);
+          if (LiveRange *LR = LIS.getCachedRegUnit(*Units)) {
+            if (VNInfo *VNI = LR->getVNInfoAt(Idx))
+              LR->removeValNo(VNI);
           }
         }
       }
diff --git a/lib/CodeGen/LiveRegMatrix.cpp b/lib/CodeGen/LiveRegMatrix.cpp
index 0ef069f478..1d801ac914 100644
--- a/lib/CodeGen/LiveRegMatrix.cpp
+++ b/lib/CodeGen/LiveRegMatrix.cpp
@@ -119,9 +119,11 @@ bool LiveRegMatrix::checkRegUnitInterference(LiveInterval &VirtReg,
   if (VirtReg.empty())
     return false;
   CoalescerPair CP(VirtReg.reg, PhysReg, *TRI);
-  for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units)
-    if (VirtReg.overlaps(LIS->getRegUnit(*Units), CP, *LIS->getSlotIndexes()))
+  for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
+    const LiveRange &UnitRange = LIS->getRegUnit(*Units);
+    if (VirtReg.overlaps(UnitRange, CP, *LIS->getSlotIndexes()))
       return true;
+  }
   return false;
 }
 
diff --git a/lib/CodeGen/MachineVerifier.cpp b/lib/CodeGen/MachineVerifier.cpp
index 062c7ac34d..e9bf617349 100644
--- a/lib/CodeGen/MachineVerifier.cpp
+++ b/lib/CodeGen/MachineVerifier.cpp
@@ -1018,16 +1018,16 @@ void MachineVerifier::checkLiveness(const MachineOperand *MO, unsigned MONum) {
       // Check the cached regunit intervals.
       if (TargetRegisterInfo::isPhysicalRegister(Reg) && !isReserved(Reg)) {
         for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units) {
-          if (const LiveInterval *LI = LiveInts->getCachedRegUnit(*Units)) {
-            LiveQueryResult LRQ = LI->Query(UseIdx);
+          if (const LiveRange *LR = LiveInts->getCachedRegUnit(*Units)) {
+            LiveQueryResult LRQ = LR->Query(UseIdx);
             if (!LRQ.valueIn()) {
               report("No live segment at use", MO, MONum);
               *OS << UseIdx << " is not live in " << PrintRegUnit(*Units, TRI)
-                  << ' ' << *LI << '\n';
+                  << ' ' << *LR << '\n';
             }
             if (MO->isKill() && !LRQ.isKill()) {
               report("Live range continues after kill flag", MO, MONum);
-              *OS << PrintRegUnit(*Units, TRI) << ' ' << *LI << '\n';
+              *OS << PrintRegUnit(*Units, TRI) << ' ' << *LR << '\n';
             }
           }
         }
@@ -1352,8 +1352,8 @@ void MachineVerifier::verifyLiveIntervals() {
 
   // Verify all the cached regunit intervals.
   for (unsigned i = 0, e = TRI->getNumRegUnits(); i != e; ++i)
-    if (const LiveInterval *LI = LiveInts->getCachedRegUnit(i))
-      verifyLiveInterval(*LI);
+    if (const LiveRange *LR = LiveInts->getCachedRegUnit(i))
+      verifyLiveRange(*LR, i);
 }
 
 void MachineVerifier::verifyLiveRangeValue(const LiveRange &LR,
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 3fa5243220..9ba2e291a1 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -1466,9 +1466,9 @@ void RAGreedy::calcGapWeights(unsigned PhysReg,
 
   // Add fixed interference.
   for (MCRegUnitIterator Units(PhysReg, TRI); Units.isValid(); ++Units) {
-    const LiveInterval &LI = LIS->getRegUnit(*Units);
-    LiveInterval::const_iterator I = LI.find(StartIdx);
-    LiveInterval::const_iterator E = LI.end();
+    const LiveRange &LR = LIS->getRegUnit(*Units);
+    LiveRange::const_iterator I = LR.find(StartIdx);
+    LiveRange::const_iterator E = LR.end();
 
     // Same loop as above. Mark any overlapped gaps as HUGE_VALF.
     for (unsigned Gap = 0; I != E && I->start < StopIdx; ++I) {
diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp
index e36c52fe06..548c32fdcf 100644
--- a/lib/CodeGen/RegisterCoalescer.cpp
+++ b/lib/CodeGen/RegisterCoalescer.cpp
@@ -874,8 +874,8 @@ bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP,
   for (unsigned i = 0, e = NewMIImplDefs.size(); i != e; ++i) {
     unsigned Reg = NewMIImplDefs[i];
     for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units)
-      if (LiveInterval *LI = LIS->getCachedRegUnit(*Units))
-        LI->createDeadDef(NewMIIdx.getRegSlot(), LIS->getVNInfoAllocator());
+      if (LiveRange *LR = LIS->getCachedRegUnit(*Units))
+        LR->createDeadDef(NewMIIdx.getRegSlot(), LIS->getVNInfoAllocator());
   }
 
   DEBUG(dbgs() << "Remat: " << *NewMI);
diff --git a/lib/CodeGen/RegisterPressure.cpp b/lib/CodeGen/RegisterPressure.cpp
index 2f273a3fd3..78985d475c 100644
--- a/lib/CodeGen/RegisterPressure.cpp
+++ b/lib/CodeGen/RegisterPressure.cpp
@@ -147,7 +147,7 @@ void RegionPressure::openBottom(MachineBasicBlock::const_iterator PrevBottom) {
   LiveInRegs.clear();
 }
 
-const LiveInterval *RegPressureTracker::getInterval(unsigned Reg) const {
+const LiveRange *RegPressureTracker::getLiveRange(unsigned Reg) const {
   if (TargetRegisterInfo::isVirtualRegister(Reg))
     return &LIS->getInterval(Reg);
   return LIS->getCachedRegUnit(Reg);
@@ -510,10 +510,9 @@ bool RegPressureTracker::recede(SmallVectorImpl<unsigned> *LiveUses,
     if (!LiveRegs.contains(Reg)) {
       // Adjust liveouts if LiveIntervals are available.
       if (RequireIntervals) {
-        const LiveInterval *LI = getInterval(Reg);
-        // Check if this LR is killed and not redefined here.
-        if (LI) {
-          LiveQueryResult LRQ = LI->Query(SlotIdx);
+        const LiveRange *LR = getLiveRange(Reg);
+        if (LR) {
+          LiveQueryResult LRQ = LR->Query(SlotIdx);
           if (!LRQ.isKill() && !LRQ.valueDefined())
             discoverLiveOut(Reg);
         }
@@ -570,8 +569,8 @@ bool RegPressureTracker::advance() {
     // Kill liveness at last uses.
     bool lastUse = false;
     if (RequireIntervals) {
-      const LiveInterval *LI = getInterval(Reg);
-      lastUse = LI && LI->Query(SlotIdx).isKill();
+      const LiveRange *LR = getLiveRange(Reg);
+      lastUse = LR && LR->Query(SlotIdx).isKill();
     }
     else {
       // Allocatable physregs are always single-use before register rewriting.
@@ -894,11 +893,12 @@ void RegPressureTracker::bumpDownwardPressure(const MachineInstr *MI) {
       // FIXME: allow the caller to pass in the list of vreg uses that remain
       // to be bottom-scheduled to avoid searching uses at each query.
       SlotIndex CurrIdx = getCurrSlot();
-      const LiveInterval *LI = getInterval(Reg);
-      if (LI) {
-        LiveQueryResult LRQ = LI->Query(SlotIdx);
-        if (LRQ.isKill() && !findUseBetween(Reg, CurrIdx, SlotIdx, MRI, LIS))
+      const LiveRange *LR = getLiveRange(Reg);
+      if (LR) {
+        LiveQueryResult LRQ = LR->Query(SlotIdx);
+        if (LRQ.isKill() && !findUseBetween(Reg, CurrIdx, SlotIdx, MRI, LIS)) {
           decreaseRegPressure(Reg);
+        }
       }
     }
     else if (!TargetRegisterInfo::isVirtualRegister(Reg)) {