X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FRegisterCoalescer.cpp;h=0bda4c7998717a419428987128081d6fd4ea88cf;hb=01d8611240d26dbf124d216983d2396234f62b95;hp=c776dd312250b61b37cb40ff389a1eee4f455f1f;hpb=0d293e45b66c742fdbc3998209bb20ed6c5806bf;p=oota-llvm.git

diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp
index c776dd31225..0bda4c79987 100644
--- a/lib/CodeGen/RegisterCoalescer.cpp
+++ b/lib/CodeGen/RegisterCoalescer.cpp
@@ -13,9 +13,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "regalloc"
 #include "RegisterCoalescer.h"
-#include "llvm/ADT/OwningPtr.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
@@ -43,6 +41,8 @@
 #include <cmath>
 using namespace llvm;
 
+#define DEBUG_TYPE "regalloc"
+
 STATISTIC(numJoins    , "Number of interval joins performed");
 STATISTIC(numCrossRCs , "Number of cross class joins performed");
 STATISTIC(numCommutes , "Number of instruction commuting performed");
@@ -112,7 +112,7 @@ namespace {
     void eliminateDeadDefs();
 
     /// LiveRangeEdit callback.
-    void LRE_WillEraseInstruction(MachineInstr *MI);
+    void LRE_WillEraseInstruction(MachineInstr *MI) override;
 
     /// coalesceLocals - coalesce the LocalWorkList.
     void coalesceLocals();
@@ -188,15 +188,15 @@ namespace {
       initializeRegisterCoalescerPass(*PassRegistry::getPassRegistry());
     }
 
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+    void getAnalysisUsage(AnalysisUsage &AU) const override;
 
-    virtual void releaseMemory();
+    void releaseMemory() override;
 
     /// runOnMachineFunction - pass entry point
-    virtual bool runOnMachineFunction(MachineFunction&);
+    bool runOnMachineFunction(MachineFunction&) override;
 
     /// print - Implement the dump method.
-    virtual void print(raw_ostream &O, const Module* = 0) const;
+    void print(raw_ostream &O, const Module* = nullptr) const override;
   };
 } /// end anonymous namespace
 
@@ -241,9 +241,8 @@ static bool isSplitEdge(const MachineBasicBlock *MBB) {
   if (MBB->pred_size() != 1 || MBB->succ_size() != 1)
     return false;
 
-  for (MachineBasicBlock::const_iterator MII = MBB->begin(), E = MBB->end();
-       MII != E; ++MII) {
-    if (!MII->isCopyLike() && !MII->isUnconditionalBranch())
+  for (const auto &MI : *MBB) {
+    if (!MI.isCopyLike() && !MI.isUnconditionalBranch())
       return false;
   }
   return true;
@@ -252,7 +251,7 @@ static bool isSplitEdge(const MachineBasicBlock *MBB) {
 bool CoalescerPair::setRegisters(const MachineInstr *MI) {
   SrcReg = DstReg = 0;
   SrcIdx = DstIdx = 0;
-  NewRC = 0;
+  NewRC = nullptr;
   Flipped = CrossClass = false;
 
   unsigned Src, Dst, SrcSub, DstSub;
@@ -283,7 +282,6 @@ bool CoalescerPair::setRegisters(const MachineInstr *MI) {
     if (SrcSub) {
       Dst = TRI.getMatchingSuperReg(Dst, SrcSub, MRI.getRegClass(Src));
       if (!Dst) return false;
-      SrcSub = 0;
     } else if (!MRI.getRegClass(Src)->contains(Dst)) {
       return false;
     }
@@ -399,7 +397,8 @@ void RegisterCoalescer::getAnalysisUsage(AnalysisUsage &AU) const {
 
 void RegisterCoalescer::eliminateDeadDefs() {
   SmallVector<unsigned, 8> NewRegs;
-  LiveRangeEdit(0, NewRegs, *MF, *LIS, 0, this).eliminateDeadDefs(DeadDefs);
+  LiveRangeEdit(nullptr, NewRegs, *MF, *LIS,
+                nullptr, this).eliminateDeadDefs(DeadDefs);
 }
 
 // Callback from eliminateDeadDefs().
@@ -434,11 +433,11 @@ bool RegisterCoalescer::adjustCopiesBackFrom(const CoalescerPair &CP,
     LIS->getInterval(CP.isFlipped() ? CP.getSrcReg() : CP.getDstReg());
   SlotIndex CopyIdx = LIS->getInstructionIndex(CopyMI).getRegSlot();
 
-  // BValNo is a value number in B that is defined by a copy from A.  'B3' in
+  // BValNo is a value number in B that is defined by a copy from A.  'B1' in
   // the example above.
-  LiveInterval::iterator BLR = IntB.FindLiveRangeContaining(CopyIdx);
-  if (BLR == IntB.end()) return false;
-  VNInfo *BValNo = BLR->valno;
+  LiveInterval::iterator BS = IntB.FindSegmentContaining(CopyIdx);
+  if (BS == IntB.end()) return false;
+  VNInfo *BValNo = BS->valno;
 
   // Get the location that B is defined at.  Two options: either this value has
   // an unknown definition point or it is defined at CopyIdx.  If unknown, we
@@ -447,10 +446,10 @@ bool RegisterCoalescer::adjustCopiesBackFrom(const CoalescerPair &CP,
 
   // AValNo is the value number in A that defines the copy, A3 in the example.
   SlotIndex CopyUseIdx = CopyIdx.getRegSlot(true);
-  LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyUseIdx);
-  // The live range might not exist after fun with physreg coalescing.
-  if (ALR == IntA.end()) return false;
-  VNInfo *AValNo = ALR->valno;
+  LiveInterval::iterator AS = IntA.FindSegmentContaining(CopyUseIdx);
+  // The live segment might not exist after fun with physreg coalescing.
+  if (AS == IntA.end()) return false;
+  VNInfo *AValNo = AS->valno;
 
   // If AValNo is defined as a copy from IntB, we can potentially process this.
   // Get the instruction that defines this value number.
@@ -459,54 +458,54 @@ bool RegisterCoalescer::adjustCopiesBackFrom(const CoalescerPair &CP,
   if (!CP.isCoalescable(ACopyMI) || !ACopyMI->isFullCopy())
     return false;
 
-  // Get the LiveRange in IntB that this value number starts with.
-  LiveInterval::iterator ValLR =
-    IntB.FindLiveRangeContaining(AValNo->def.getPrevSlot());
-  if (ValLR == IntB.end())
+  // Get the Segment in IntB that this value number starts with.
+  LiveInterval::iterator ValS =
+    IntB.FindSegmentContaining(AValNo->def.getPrevSlot());
+  if (ValS == IntB.end())
     return false;
 
-  // Make sure that the end of the live range is inside the same block as
+  // Make sure that the end of the live segment is inside the same block as
   // CopyMI.
-  MachineInstr *ValLREndInst =
-    LIS->getInstructionFromIndex(ValLR->end.getPrevSlot());
-  if (!ValLREndInst || ValLREndInst->getParent() != CopyMI->getParent())
+  MachineInstr *ValSEndInst =
+    LIS->getInstructionFromIndex(ValS->end.getPrevSlot());
+  if (!ValSEndInst || ValSEndInst->getParent() != CopyMI->getParent())
     return false;
 
-  // Okay, we now know that ValLR ends in the same block that the CopyMI
-  // live-range starts.  If there are no intervening live ranges between them in
-  // IntB, we can merge them.
-  if (ValLR+1 != BLR) return false;
+  // Okay, we now know that ValS ends in the same block that the CopyMI
+  // live-range starts.  If there are no intervening live segments between them
+  // in IntB, we can merge them.
+  if (ValS+1 != BS) return false;
 
   DEBUG(dbgs() << "Extending: " << PrintReg(IntB.reg, TRI));
 
-  SlotIndex FillerStart = ValLR->end, FillerEnd = BLR->start;
+  SlotIndex FillerStart = ValS->end, FillerEnd = BS->start;
   // We are about to delete CopyMI, so need to remove it as the 'instruction
   // that defines this value #'. Update the valnum with the new defining
   // instruction #.
   BValNo->def = FillerStart;
 
   // Okay, we can merge them.  We need to insert a new liverange:
-  // [ValLR.end, BLR.begin) of either value number, then we merge the
+  // [ValS.end, BS.begin) of either value number, then we merge the
   // two value numbers.
-  IntB.addRange(LiveRange(FillerStart, FillerEnd, BValNo));
+  IntB.addSegment(LiveInterval::Segment(FillerStart, FillerEnd, BValNo));
 
   // Okay, merge "B1" into the same value number as "B0".
-  if (BValNo != ValLR->valno)
-    IntB.MergeValueNumberInto(BValNo, ValLR->valno);
+  if (BValNo != ValS->valno)
+    IntB.MergeValueNumberInto(BValNo, ValS->valno);
   DEBUG(dbgs() << "   result = " << IntB << '\n');
 
   // If the source instruction was killing the source register before the
   // merge, unset the isKill marker given the live range has been extended.
-  int UIdx = ValLREndInst->findRegisterUseOperandIdx(IntB.reg, true);
+  int UIdx = ValSEndInst->findRegisterUseOperandIdx(IntB.reg, true);
   if (UIdx != -1) {
-    ValLREndInst->getOperand(UIdx).setIsKill(false);
+    ValSEndInst->getOperand(UIdx).setIsKill(false);
   }
 
   // Rewrite the copy. If the copy instruction was killing the destination
   // register before the merge, find the last use and trim the live range. That
   // will also add the isKill marker.
   CopyMI->substituteRegister(IntA.reg, IntB.reg, 0, *TRI);
-  if (ALR->end == CopyIdx)
+  if (AS->end == CopyIdx)
     LIS->shrinkToUses(&IntA);
 
   ++numExtends;
@@ -612,7 +611,7 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
 
   MachineOperand &NewDstMO = DefMI->getOperand(NewDstIdx);
   unsigned NewReg = NewDstMO.getReg();
-  if (NewReg != IntB.reg || !LiveRangeQuery(IntB, AValNo->def).isKill())
+  if (NewReg != IntB.reg || !IntB.Query(AValNo->def).isKill())
     return false;
 
   // Make sure there are no other definitions of IntB that would reach the
@@ -622,16 +621,15 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
 
   // If some of the uses of IntA.reg is already coalesced away, return false.
   // It's not possible to determine whether it's safe to perform the coalescing.
-  for (MachineRegisterInfo::use_nodbg_iterator UI =
-         MRI->use_nodbg_begin(IntA.reg),
-       UE = MRI->use_nodbg_end(); UI != UE; ++UI) {
-    MachineInstr *UseMI = &*UI;
+  for (MachineOperand &MO : MRI->use_nodbg_operands(IntA.reg)) {
+    MachineInstr *UseMI = MO.getParent();
+    unsigned OpNo = &MO - &UseMI->getOperand(0);
     SlotIndex UseIdx = LIS->getInstructionIndex(UseMI);
-    LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx);
-    if (ULR == IntA.end() || ULR->valno != AValNo)
+    LiveInterval::iterator US = IntA.FindSegmentContaining(UseIdx);
+    if (US == IntA.end() || US->valno != AValNo)
       continue;
     // If this use is tied to a def, we can't rewrite the register.
-    if (UseMI->isRegTiedToDefOperand(UI.getOperandNo()))
+    if (UseMI->isRegTiedToDefOperand(OpNo))
       return false;
   }
 
@@ -669,8 +667,8 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
   // Update uses of IntA of the specific Val# with IntB.
   for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(IntA.reg),
          UE = MRI->use_end(); UI != UE;) {
-    MachineOperand &UseMO = UI.getOperand();
-    MachineInstr *UseMI = &*UI;
+    MachineOperand &UseMO = *UI;
+    MachineInstr *UseMI = UseMO.getParent();
     ++UI;
     if (UseMI->isDebugValue()) {
       // FIXME These don't have an instruction index.  Not clear we have enough
@@ -679,8 +677,8 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
       continue;
     }
     SlotIndex UseIdx = LIS->getInstructionIndex(UseMI).getRegSlot(true);
-    LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx);
-    if (ULR == IntA.end() || ULR->valno != AValNo)
+    LiveInterval::iterator US = IntA.FindSegmentContaining(UseIdx);
+    if (US == IntA.end() || US->valno != AValNo)
       continue;
     // Kill flags are no longer accurate. They are recomputed after RA.
     UseMO.setIsKill(false);
@@ -710,14 +708,14 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
     UseMI->eraseFromParent();
   }
 
-  // Extend BValNo by merging in IntA live ranges of AValNo. Val# definition
+  // Extend BValNo by merging in IntA live segments of AValNo. Val# definition
   // is updated.
   VNInfo *ValNo = BValNo;
   ValNo->def = AValNo->def;
   for (LiveInterval::iterator AI = IntA.begin(), AE = IntA.end();
        AI != AE; ++AI) {
     if (AI->valno != AValNo) continue;
-    IntB.addRange(LiveRange(AI->start, AI->end, ValNo));
+    IntB.addSegment(LiveInterval::Segment(AI->start, AI->end, ValNo));
   }
   DEBUG(dbgs() << "\t\textended: " << IntB << '\n');
 
@@ -742,7 +740,7 @@ bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP,
 
   LiveInterval &SrcInt = LIS->getInterval(SrcReg);
   SlotIndex CopyIdx = LIS->getInstructionIndex(CopyMI);
-  VNInfo *ValNo = LiveRangeQuery(SrcInt, CopyIdx).valueIn();
+  VNInfo *ValNo = SrcInt.Query(CopyIdx).valueIn();
   assert(ValNo && "CopyMI input register not live");
   if (ValNo->isPHIDef() || ValNo->isUnused())
     return false;
@@ -769,6 +767,14 @@ bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP,
   if (DstOperand.getSubReg() && !DstOperand.isUndef())
     return false;
 
+  // If both SrcIdx and DstIdx are set, correct rematerialization would widen
+  // the register substantially (beyond both source and dest size). This is bad
+  // for performance since it can cascade through a function, introducing many
+  // extra spills and fills (e.g. ARM can easily end up copying QQQQPR registers
+  // around after a few subreg copies).
+  if (SrcIdx && DstIdx)
+    return false;
+
   const TargetRegisterClass *DefRC = TII->getRegClass(MCID, 0, TRI, *MF);
   if (!DefMI->isImplicitDef()) {
     if (TargetRegisterInfo::isPhysicalRegister(DstReg)) {
@@ -793,9 +799,9 @@ bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP,
 
   MachineBasicBlock *MBB = CopyMI->getParent();
   MachineBasicBlock::iterator MII =
-    llvm::next(MachineBasicBlock::iterator(CopyMI));
+    std::next(MachineBasicBlock::iterator(CopyMI));
   TII->reMaterialize(*MBB, MII, DstReg, SrcIdx, DefMI, *TRI);
-  MachineInstr *NewMI = prior(MII);
+  MachineInstr *NewMI = std::prev(MII);
 
   LIS->ReplaceMachineInstrInMaps(CopyMI, NewMI);
   CopyMI->eraseFromParent();
@@ -816,31 +822,19 @@ bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP,
   }
 
   if (TargetRegisterInfo::isVirtualRegister(DstReg)) {
+    const TargetRegisterClass *NewRC = CP.getNewRC();
     unsigned NewIdx = NewMI->getOperand(0).getSubReg();
-    const TargetRegisterClass *RCForInst;
+
     if (NewIdx)
-      RCForInst = TRI->getMatchingSuperRegClass(MRI->getRegClass(DstReg), DefRC,
-                                                NewIdx);
-
-    if (MRI->constrainRegClass(DstReg, DefRC)) {
-      // The materialized instruction is quite capable of setting DstReg
-      // directly, but it may still have a now-trivial subregister index which
-      // we should clear.
-      NewMI->getOperand(0).setSubReg(0);
-    } else if (NewIdx && RCForInst) {
-      // The subreg index on NewMI is essential; we still have to make sure
-      // DstReg:idx is in a class that NewMI can use.
-      MRI->constrainRegClass(DstReg, RCForInst);
-    } else {
-      // DstReg is actually incompatible with NewMI, we have to move to a
-      // super-reg's class. This could come from a sequence like:
-      //     GR32 = MOV32r0
-      //     GR8 = COPY GR32:sub_8
-      MRI->setRegClass(DstReg, CP.getNewRC());
-      updateRegDefsUses(DstReg, DstReg, DstIdx);
-      NewMI->getOperand(0).setSubReg(
-          TRI->composeSubRegIndices(SrcIdx, DefMI->getOperand(0).getSubReg()));
-    }
+      NewRC = TRI->getMatchingSuperRegClass(NewRC, DefRC, NewIdx);
+    else
+      NewRC = TRI->getCommonSubClass(NewRC, DefRC);
+
+    assert(NewRC && "subreg chosen for remat incompatible with instruction");
+    MRI->setRegClass(DstReg, NewRC);
+
+    updateRegDefsUses(DstReg, DstReg, DstIdx);
+    NewMI->getOperand(0).setSubReg(NewIdx);
   } else if (NewMI->getOperand(0).getReg() != CopyDstReg) {
     // The New instruction may be defining a sub-register of what's actually
     // been asked for. If so it must implicitly define the whole thing.
@@ -851,6 +845,27 @@ bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP,
                                                 true  /*IsDef*/,
                                                 true  /*IsImp*/,
                                                 false /*IsKill*/));
+    // Record small dead def live-ranges for all the subregisters
+    // of the destination register.
+    // Otherwise, variables that live through may miss some
+    // interferences, thus creating invalid allocation.
+    // E.g., i386 code:
+    // vreg1 = somedef ; vreg1 GR8
+    // vreg2 = remat ; vreg2 GR32
+    // CL = COPY vreg2.sub_8bit
+    // = somedef vreg1 ; vreg1 GR8
+    // =>
+    // vreg1 = somedef ; vreg1 GR8
+    // ECX<def, dead> = remat ; CL<imp-def>
+    // = somedef vreg1 ; vreg1 GR8
+    // vreg1 will see the inteferences with CL but not with CH since
+    // no live-ranges would have been created for ECX.
+    // Fix that!
+    SlotIndex NewMIIdx = LIS->getInstructionIndex(NewMI);
+    for (MCRegUnitIterator Units(NewMI->getOperand(0).getReg(), TRI);
+         Units.isValid(); ++Units)
+      if (LiveRange *LR = LIS->getCachedRegUnit(*Units))
+        LR->createDeadDef(NewMIIdx.getRegSlot(), LIS->getVNInfoAllocator());
   }
 
   if (NewMI->getOperand(0).getSubReg())
@@ -874,8 +889,8 @@ 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);
@@ -909,17 +924,14 @@ bool RegisterCoalescer::eliminateUndefCopy(MachineInstr *CopyMI,
   // No intervals are live-in to CopyMI - it is undef.
   if (CP.isFlipped())
     DstInt = SrcInt;
-  SrcInt = 0;
+  SrcInt = nullptr;
 
   VNInfo *DeadVNI = DstInt->getVNInfoAt(Idx.getRegSlot());
   assert(DeadVNI && "No value defined in DstInt");
   DstInt->removeValNo(DeadVNI);
 
   // Find new undef uses.
-  for (MachineRegisterInfo::reg_nodbg_iterator
-         I = MRI->reg_nodbg_begin(DstInt->reg), E = MRI->reg_nodbg_end();
-       I != E; ++I) {
-    MachineOperand &MO = I.getOperand();
+  for (MachineOperand &MO : MRI->reg_nodbg_operands(DstInt->reg)) {
     if (MO.isDef() || MO.isUndef())
       continue;
     MachineInstr *MI = MO.getParent();
@@ -941,11 +953,14 @@ void RegisterCoalescer::updateRegDefsUses(unsigned SrcReg,
                                           unsigned DstReg,
                                           unsigned SubIdx) {
   bool DstIsPhys = TargetRegisterInfo::isPhysicalRegister(DstReg);
-  LiveInterval *DstInt = DstIsPhys ? 0 : &LIS->getInterval(DstReg);
+  LiveInterval *DstInt = DstIsPhys ? nullptr : &LIS->getInterval(DstReg);
 
   SmallPtrSet<MachineInstr*, 8> Visited;
-  for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(SrcReg);
-       MachineInstr *UseMI = I.skipInstruction();) {
+  for (MachineRegisterInfo::reg_instr_iterator
+       I = MRI->reg_instr_begin(SrcReg), E = MRI->reg_instr_end();
+       I != E; ) {
+    MachineInstr *UseMI = &*(I++);
+
     // Each instruction can only be rewritten once because sub-register
     // composition is not always idempotent. When SrcReg != DstReg, rewriting
     // the UseMI operands removes them from the SrcReg use-def chain, but when
@@ -956,7 +971,7 @@ void RegisterCoalescer::updateRegDefsUses(unsigned SrcReg,
 
     SmallVector<unsigned,8> Ops;
     bool Reads, Writes;
-    tie(Reads, Writes) = UseMI->readsWritesVirtualRegister(SrcReg, &Ops);
+    std::tie(Reads, Writes) = UseMI->readsWritesVirtualRegister(SrcReg, &Ops);
 
     // If SrcReg wasn't read, it may still be the case that DstReg is live-in
     // because SrcReg is a sub-register.
@@ -1022,6 +1037,23 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
     return false;
   }
 
+  if (CP.getNewRC()) {
+    const TargetSubtargetInfo &ST = TM->getSubtarget<TargetSubtargetInfo>();
+    auto SrcRC = MRI->getRegClass(CP.getSrcReg());
+    auto DstRC = MRI->getRegClass(CP.getDstReg());
+    unsigned SrcIdx = CP.getSrcIdx();
+    unsigned DstIdx = CP.getDstIdx();
+    if (CP.isFlipped()) {
+      std::swap(SrcIdx, DstIdx);
+      std::swap(SrcRC, DstRC);
+    }
+    if (!ST.shouldCoalesce(CopyMI, SrcRC, SrcIdx, DstRC, DstIdx,
+                            CP.getNewRC())) {
+      DEBUG(dbgs() << "\tSubtarget bailed on coalescing.\n");
+      return false;
+    }
+  }
+
   // Dead code elimination. This really should be handled by MachineDCE, but
   // sometimes dead copies slip through, and we can't generate invalid live
   // ranges.
@@ -1046,7 +1078,7 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
   if (CP.getSrcReg() == CP.getDstReg()) {
     LiveInterval &LI = LIS->getInterval(CP.getSrcReg());
     DEBUG(dbgs() << "\tCopy already coalesced: " << LI << '\n');
-    LiveRangeQuery LRQ(LI, LIS->getInstructionIndex(CopyMI));
+    LiveQueryResult LRQ = LI.Query(LIS->getInstructionIndex(CopyMI));
     if (VNInfo *DefVNI = LRQ.valueDefined()) {
       VNInfo *ReadVNI = LRQ.valueIn();
       assert(ReadVNI && "No value before copy and no <undef> flag.");
@@ -1107,7 +1139,8 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
     if (reMaterializeTrivialDef(CP, CopyMI, IsDefCopy))
       return true;
 
-    // If we can eliminate the copy without merging the live ranges, do so now.
+    // If we can eliminate the copy without merging the live segments, do so
+    // now.
     if (!CP.isPartial() && !CP.isPhys()) {
       if (adjustCopiesBackFrom(CP, CopyMI) ||
           removeCopyByCommutingDef(CP, CopyMI)) {
@@ -1155,10 +1188,12 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
   TRI->UpdateRegAllocHint(CP.getSrcReg(), CP.getDstReg(), *MF);
 
   DEBUG({
-    dbgs() << "\tJoined. Result = " << PrintReg(CP.getDstReg(), TRI);
-    if (!CP.isPhys())
+    dbgs() << "\tJoined. Result = ";
+    if (CP.isPhys())
+      dbgs() << PrintReg(CP.getDstReg(), TRI);
+    else
       dbgs() << LIS->getInterval(CP.getDstReg());
-     dbgs() << '\n';
+    dbgs() << '\n';
   });
 
   ++numJoins;
@@ -1170,8 +1205,7 @@ bool RegisterCoalescer::joinReservedPhysReg(CoalescerPair &CP) {
   assert(CP.isPhys() && "Must be a physreg copy");
   assert(MRI->isReserved(CP.getDstReg()) && "Not a reserved register");
   LiveInterval &RHS = LIS->getInterval(CP.getSrcReg());
-  DEBUG(dbgs() << "\t\tRHS = " << PrintReg(CP.getSrcReg()) << ' ' << RHS
-               << '\n');
+  DEBUG(dbgs() << "\t\tRHS = " << RHS << '\n');
 
   assert(CP.isFlipped() && RHS.containsOneValue() &&
          "Invalid join with reserved register");
@@ -1360,7 +1394,7 @@ class JoinVals {
     bool PrunedComputed;
 
     Val() : Resolution(CR_Keep), WriteLanes(0), ValidLanes(0),
-            RedefVNI(0), OtherVNI(0), ErasableImplicitDef(false),
+            RedefVNI(nullptr), OtherVNI(nullptr), ErasableImplicitDef(false),
             Pruned(false), PrunedComputed(false) {}
 
     bool isAnalyzed() const { return WriteLanes != 0; }
@@ -1440,7 +1474,7 @@ VNInfo *JoinVals::stripCopies(VNInfo *VNI) {
     unsigned Reg = MI->getOperand(1).getReg();
     if (!TargetRegisterInfo::isVirtualRegister(Reg))
       break;
-    LiveRangeQuery LRQ(LIS->getInterval(Reg), VNI->def);
+    LiveQueryResult LRQ = LIS->getInterval(Reg).Query(VNI->def);
     if (!LRQ.valueIn())
       break;
     VNI = LRQ.valueIn();
@@ -1466,7 +1500,7 @@ JoinVals::analyzeValue(unsigned ValNo, JoinVals &Other) {
   }
 
   // Get the instruction defining this value, compute the lanes written.
-  const MachineInstr *DefMI = 0;
+  const MachineInstr *DefMI = nullptr;
   if (VNI->isPHIDef()) {
     // Conservatively assume that all lanes in a PHI are valid.
     V.ValidLanes = V.WriteLanes = TRI->getSubRegIndexLaneMask(SubIdx);
@@ -1491,7 +1525,7 @@ JoinVals::analyzeValue(unsigned ValNo, JoinVals &Other) {
     // The <read-undef> flag on the def operand means that old lane values are
     // not important.
     if (Redef) {
-      V.RedefVNI = LiveRangeQuery(LI, VNI->def).valueIn();
+      V.RedefVNI = LI.Query(VNI->def).valueIn();
       assert(V.RedefVNI && "Instruction is reading nonexistent value");
       computeAssignment(V.RedefVNI->id, Other);
       V.ValidLanes |= Vals[V.RedefVNI->id].ValidLanes;
@@ -1508,7 +1542,7 @@ JoinVals::analyzeValue(unsigned ValNo, JoinVals &Other) {
   }
 
   // Find the value in Other that overlaps VNI->def, if any.
-  LiveRangeQuery OtherLRQ(Other.LI, VNI->def);
+  LiveQueryResult OtherLRQ = Other.LI.Query(VNI->def);
 
   // It is possible that both values are defined by the same instruction, or
   // the values are PHIs defined in the same block. When that happens, the two
@@ -1967,8 +2001,8 @@ bool RegisterCoalescer::joinVirtRegs(CoalescerPair &CP) {
   JoinVals RHSVals(RHS, CP.getSrcIdx(), NewVNInfo, CP, LIS, TRI);
   JoinVals LHSVals(LHS, CP.getDstIdx(), NewVNInfo, CP, LIS, TRI);
 
-  DEBUG(dbgs() << "\t\tRHS = " << PrintReg(CP.getSrcReg()) << ' ' << RHS
-               << "\n\t\tLHS = " << PrintReg(CP.getDstReg()) << ' ' << LHS
+  DEBUG(dbgs() << "\t\tRHS = " << RHS
+               << "\n\t\tLHS = " << LHS
                << '\n');
 
   // First compute NewVNInfo and the simple value mappings.
@@ -2014,7 +2048,7 @@ bool RegisterCoalescer::joinVirtRegs(CoalescerPair &CP) {
   // CR_Replace conflicts.
   DEBUG(dbgs() << "\t\trestoring liveness to " << EndPoints.size()
                << " points: " << LHS << '\n');
-  LIS->extendToIndices(&LHS, EndPoints);
+  LIS->extendToIndices(LHS, EndPoints);
   return true;
 }
 
@@ -2090,14 +2124,14 @@ copyCoalesceWorkList(MutableArrayRef<MachineInstr*> CurrList) {
     // Skip instruction pointers that have already been erased, for example by
     // dead code elimination.
     if (ErasedInstrs.erase(CurrList[i])) {
-      CurrList[i] = 0;
+      CurrList[i] = nullptr;
       continue;
     }
     bool Again = false;
     bool Success = joinCopy(CurrList[i], Again);
     Progress |= Success;
     if (Success || !Again)
-      CurrList[i] = 0;
+      CurrList[i] = nullptr;
   }
   return Progress;
 }
@@ -2137,7 +2171,7 @@ RegisterCoalescer::copyCoalesceInMBB(MachineBasicBlock *MBB) {
     CurrList(WorkList.begin() + PrevSize, WorkList.end());
   if (copyCoalesceWorkList(CurrList))
     WorkList.erase(std::remove(WorkList.begin() + PrevSize, WorkList.end(),
-                               (MachineInstr*)0), WorkList.end());
+                               (MachineInstr*)nullptr), WorkList.end());
 }
 
 void RegisterCoalescer::coalesceLocals() {
@@ -2199,7 +2233,7 @@ bool RegisterCoalescer::runOnMachineFunction(MachineFunction &fn) {
 
   const TargetSubtargetInfo &ST = TM->getSubtarget<TargetSubtargetInfo>();
   if (EnableGlobalCopies == cl::BOU_UNSET)
-    JoinGlobalCopies = ST.enableMachineScheduler();
+    JoinGlobalCopies = ST.useMachineScheduler();
   else
     JoinGlobalCopies = (EnableGlobalCopies == cl::BOU_TRUE);