LCOV - code coverage report
Current view: top level - lib/CodeGen - TwoAddressInstructionPass.cpp (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 583 645 90.4 %
Date: 2018-06-17 00:07:59 Functions: 32 32 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===- TwoAddressInstructionPass.cpp - Two-Address instruction pass -------===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : //
      10             : // This file implements the TwoAddress instruction pass which is used
      11             : // by most register allocators. Two-Address instructions are rewritten
      12             : // from:
      13             : //
      14             : //     A = B op C
      15             : //
      16             : // to:
      17             : //
      18             : //     A = B
      19             : //     A op= C
      20             : //
      21             : // Note that if a register allocator chooses to use this pass, that it
      22             : // has to be capable of handling the non-SSA nature of these rewritten
      23             : // virtual registers.
      24             : //
      25             : // It is also worth noting that the duplicate operand of the two
      26             : // address instruction is removed.
      27             : //
      28             : //===----------------------------------------------------------------------===//
      29             : 
      30             : #include "llvm/ADT/DenseMap.h"
      31             : #include "llvm/ADT/SmallPtrSet.h"
      32             : #include "llvm/ADT/SmallSet.h"
      33             : #include "llvm/ADT/SmallVector.h"
      34             : #include "llvm/ADT/Statistic.h"
      35             : #include "llvm/ADT/iterator_range.h"
      36             : #include "llvm/Analysis/AliasAnalysis.h"
      37             : #include "llvm/CodeGen/LiveInterval.h"
      38             : #include "llvm/CodeGen/LiveIntervals.h"
      39             : #include "llvm/CodeGen/LiveVariables.h"
      40             : #include "llvm/CodeGen/MachineBasicBlock.h"
      41             : #include "llvm/CodeGen/MachineFunction.h"
      42             : #include "llvm/CodeGen/MachineFunctionPass.h"
      43             : #include "llvm/CodeGen/MachineInstr.h"
      44             : #include "llvm/CodeGen/MachineInstrBuilder.h"
      45             : #include "llvm/CodeGen/MachineOperand.h"
      46             : #include "llvm/CodeGen/MachineRegisterInfo.h"
      47             : #include "llvm/CodeGen/Passes.h"
      48             : #include "llvm/CodeGen/SlotIndexes.h"
      49             : #include "llvm/CodeGen/TargetInstrInfo.h"
      50             : #include "llvm/CodeGen/TargetOpcodes.h"
      51             : #include "llvm/CodeGen/TargetRegisterInfo.h"
      52             : #include "llvm/CodeGen/TargetSubtargetInfo.h"
      53             : #include "llvm/MC/MCInstrDesc.h"
      54             : #include "llvm/MC/MCInstrItineraries.h"
      55             : #include "llvm/Pass.h"
      56             : #include "llvm/Support/CodeGen.h"
      57             : #include "llvm/Support/CommandLine.h"
      58             : #include "llvm/Support/Debug.h"
      59             : #include "llvm/Support/ErrorHandling.h"
      60             : #include "llvm/Support/raw_ostream.h"
      61             : #include "llvm/Target/TargetMachine.h"
      62             : #include <cassert>
      63             : #include <iterator>
      64             : #include <utility>
      65             : 
      66             : using namespace llvm;
      67             : 
      68             : #define DEBUG_TYPE "twoaddressinstruction"
      69             : 
      70             : STATISTIC(NumTwoAddressInstrs, "Number of two-address instructions");
      71             : STATISTIC(NumCommuted        , "Number of instructions commuted to coalesce");
      72             : STATISTIC(NumAggrCommuted    , "Number of instructions aggressively commuted");
      73             : STATISTIC(NumConvertedTo3Addr, "Number of instructions promoted to 3-address");
      74             : STATISTIC(Num3AddrSunk,        "Number of 3-address instructions sunk");
      75             : STATISTIC(NumReSchedUps,       "Number of instructions re-scheduled up");
      76             : STATISTIC(NumReSchedDowns,     "Number of instructions re-scheduled down");
      77             : 
      78             : // Temporary flag to disable rescheduling.
      79             : static cl::opt<bool>
      80      101169 : EnableRescheduling("twoaddr-reschedule",
      81      101169 :                    cl::desc("Coalesce copies by rescheduling (default=true)"),
      82      303507 :                    cl::init(true), cl::Hidden);
      83             : 
      84             : // Limit the number of dataflow edges to traverse when evaluating the benefit
      85             : // of commuting operands.
      86      101169 : static cl::opt<unsigned> MaxDataFlowEdge(
      87      202338 :     "dataflow-edge-limit", cl::Hidden, cl::init(3),
      88      101169 :     cl::desc("Maximum number of dataflow edges to traverse when evaluating "
      89      101169 :              "the benefit of commuting operands"));
      90             : 
      91             : namespace {
      92             : 
      93       68052 : class TwoAddressInstructionPass : public MachineFunctionPass {
      94             :   MachineFunction *MF;
      95             :   const TargetInstrInfo *TII;
      96             :   const TargetRegisterInfo *TRI;
      97             :   const InstrItineraryData *InstrItins;
      98             :   MachineRegisterInfo *MRI;
      99             :   LiveVariables *LV;
     100             :   LiveIntervals *LIS;
     101             :   AliasAnalysis *AA;
     102             :   CodeGenOpt::Level OptLevel;
     103             : 
     104             :   // The current basic block being processed.
     105             :   MachineBasicBlock *MBB;
     106             : 
     107             :   // Keep track the distance of a MI from the start of the current basic block.
     108             :   DenseMap<MachineInstr*, unsigned> DistanceMap;
     109             : 
     110             :   // Set of already processed instructions in the current block.
     111             :   SmallPtrSet<MachineInstr*, 8> Processed;
     112             : 
     113             :   // Set of instructions converted to three-address by target and then sunk
     114             :   // down current basic block.
     115             :   SmallPtrSet<MachineInstr*, 8> SunkInstrs;
     116             : 
     117             :   // A map from virtual registers to physical registers which are likely targets
     118             :   // to be coalesced to due to copies from physical registers to virtual
     119             :   // registers. e.g. v1024 = move r0.
     120             :   DenseMap<unsigned, unsigned> SrcRegMap;
     121             : 
     122             :   // A map from virtual registers to physical registers which are likely targets
     123             :   // to be coalesced to due to copies to physical registers from virtual
     124             :   // registers. e.g. r1 = move v1024.
     125             :   DenseMap<unsigned, unsigned> DstRegMap;
     126             : 
     127             :   bool sink3AddrInstruction(MachineInstr *MI, unsigned Reg,
     128             :                             MachineBasicBlock::iterator OldPos);
     129             : 
     130             :   bool isRevCopyChain(unsigned FromReg, unsigned ToReg, int Maxlen);
     131             : 
     132             :   bool noUseAfterLastDef(unsigned Reg, unsigned Dist, unsigned &LastDef);
     133             : 
     134             :   bool isProfitableToCommute(unsigned regA, unsigned regB, unsigned regC,
     135             :                              MachineInstr *MI, unsigned Dist);
     136             : 
     137             :   bool commuteInstruction(MachineInstr *MI, unsigned DstIdx,
     138             :                           unsigned RegBIdx, unsigned RegCIdx, unsigned Dist);
     139             : 
     140             :   bool isProfitableToConv3Addr(unsigned RegA, unsigned RegB);
     141             : 
     142             :   bool convertInstTo3Addr(MachineBasicBlock::iterator &mi,
     143             :                           MachineBasicBlock::iterator &nmi,
     144             :                           unsigned RegA, unsigned RegB, unsigned Dist);
     145             : 
     146             :   bool isDefTooClose(unsigned Reg, unsigned Dist, MachineInstr *MI);
     147             : 
     148             :   bool rescheduleMIBelowKill(MachineBasicBlock::iterator &mi,
     149             :                              MachineBasicBlock::iterator &nmi,
     150             :                              unsigned Reg);
     151             :   bool rescheduleKillAboveMI(MachineBasicBlock::iterator &mi,
     152             :                              MachineBasicBlock::iterator &nmi,
     153             :                              unsigned Reg);
     154             : 
     155             :   bool tryInstructionTransform(MachineBasicBlock::iterator &mi,
     156             :                                MachineBasicBlock::iterator &nmi,
     157             :                                unsigned SrcIdx, unsigned DstIdx,
     158             :                                unsigned Dist, bool shouldOnlyCommute);
     159             : 
     160             :   bool tryInstructionCommute(MachineInstr *MI,
     161             :                              unsigned DstOpIdx,
     162             :                              unsigned BaseOpIdx,
     163             :                              bool BaseOpKilled,
     164             :                              unsigned Dist);
     165             :   void scanUses(unsigned DstReg);
     166             : 
     167             :   void processCopy(MachineInstr *MI);
     168             : 
     169             :   using TiedPairList = SmallVector<std::pair<unsigned, unsigned>, 4>;
     170             :   using TiedOperandMap = SmallDenseMap<unsigned, TiedPairList>;
     171             : 
     172             :   bool collectTiedOperands(MachineInstr *MI, TiedOperandMap&);
     173             :   void processTiedPairs(MachineInstr *MI, TiedPairList&, unsigned &Dist);
     174             :   void eliminateRegSequence(MachineBasicBlock::iterator&);
     175             : 
     176             : public:
     177             :   static char ID; // Pass identification, replacement for typeid
     178             : 
     179       68376 :   TwoAddressInstructionPass() : MachineFunctionPass(ID) {
     180       22792 :     initializeTwoAddressInstructionPassPass(*PassRegistry::getPassRegistry());
     181       22792 :   }
     182             : 
     183       22625 :   void getAnalysisUsage(AnalysisUsage &AU) const override {
     184       22625 :     AU.setPreservesCFG();
     185             :     AU.addUsedIfAvailable<AAResultsWrapperPass>();
     186             :     AU.addUsedIfAvailable<LiveVariables>();
     187             :     AU.addPreserved<LiveVariables>();
     188             :     AU.addPreserved<SlotIndexes>();
     189             :     AU.addPreserved<LiveIntervals>();
     190       22625 :     AU.addPreservedID(MachineLoopInfoID);
     191       22625 :     AU.addPreservedID(MachineDominatorsID);
     192       22625 :     MachineFunctionPass::getAnalysisUsage(AU);
     193       22625 :   }
     194             : 
     195             :   /// Pass entry point.
     196             :   bool runOnMachineFunction(MachineFunction&) override;
     197             : };
     198             : 
     199             : } // end anonymous namespace
     200             : 
     201             : char TwoAddressInstructionPass::ID = 0;
     202             : 
     203             : char &llvm::TwoAddressInstructionPassID = TwoAddressInstructionPass::ID;
     204             : 
     205       26770 : INITIALIZE_PASS_BEGIN(TwoAddressInstructionPass, DEBUG_TYPE,
     206             :                 "Two-Address instruction pass", false, false)
     207       26770 : INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
     208      193696 : INITIALIZE_PASS_END(TwoAddressInstructionPass, DEBUG_TYPE,
     209             :                 "Two-Address instruction pass", false, false)
     210             : 
     211             : static bool isPlainlyKilled(MachineInstr *MI, unsigned Reg, LiveIntervals *LIS);
     212             : 
     213             : /// A two-address instruction has been converted to a three-address instruction
     214             : /// to avoid clobbering a register. Try to sink it past the instruction that
     215             : /// would kill the above mentioned register to reduce register pressure.
     216        5084 : bool TwoAddressInstructionPass::
     217             : sink3AddrInstruction(MachineInstr *MI, unsigned SavedReg,
     218             :                      MachineBasicBlock::iterator OldPos) {
     219             :   // FIXME: Shouldn't we be trying to do this before we three-addressify the
     220             :   // instruction?  After this transformation is done, we no longer need
     221             :   // the instruction to be in three-address form.
     222             : 
     223             :   // Check if it's safe to move this instruction.
     224        5084 :   bool SeenStore = true; // Be conservative.
     225        5084 :   if (!MI->isSafeToMove(AA, SeenStore))
     226             :     return false;
     227             : 
     228             :   unsigned DefReg = 0;
     229        5041 :   SmallSet<unsigned, 4> UseRegs;
     230             : 
     231       65783 :   for (const MachineOperand &MO : MI->operands()) {
     232       30718 :     if (!MO.isReg())
     233       10320 :       continue;
     234       20398 :     unsigned MOReg = MO.getReg();
     235       20398 :     if (!MOReg)
     236        7786 :       continue;
     237       12612 :     if (MO.isUse() && MOReg != SavedReg)
     238        2121 :       UseRegs.insert(MO.getReg());
     239       12612 :     if (!MO.isDef())
     240        7224 :       continue;
     241        5388 :     if (MO.isImplicit())
     242             :       // Don't try to move it if it implicitly defines a register.
     243             :       return false;
     244        5041 :     if (DefReg)
     245             :       // For now, don't move any instructions that define multiple registers.
     246             :       return false;
     247        5041 :     DefReg = MO.getReg();
     248             :   }
     249             : 
     250             :   // Find the instruction that kills SavedReg.
     251             :   MachineInstr *KillMI = nullptr;
     252        4694 :   if (LIS) {
     253           0 :     LiveInterval &LI = LIS->getInterval(SavedReg);
     254             :     assert(LI.end() != LI.begin() &&
     255             :            "Reg should not have empty live interval.");
     256             : 
     257           0 :     SlotIndex MBBEndIdx = LIS->getMBBEndIdx(MBB).getPrevSlot();
     258           0 :     LiveInterval::const_iterator I = LI.find(MBBEndIdx);
     259           0 :     if (I != LI.end() && I->start < MBBEndIdx)
     260             :       return false;
     261             : 
     262             :     --I;
     263             :     KillMI = LIS->getInstructionFromIndex(I->end);
     264             :   }
     265           0 :   if (!KillMI) {
     266       32643 :     for (MachineOperand &UseMO : MRI->use_nodbg_operands(SavedReg)) {
     267       27542 :       if (!UseMO.isKill())
     268             :         continue;
     269        4287 :       KillMI = UseMO.getParent();
     270        4287 :       break;
     271             :     }
     272             :   }
     273             : 
     274             :   // If we find the instruction that kills SavedReg, and it is in an
     275             :   // appropriate location, we can try to sink the current instruction
     276             :   // past it.
     277        6365 :   if (!KillMI || KillMI->getParent() != MBB || KillMI == MI ||
     278        5954 :       MachineBasicBlock::iterator(KillMI) == OldPos || KillMI->isTerminator())
     279             :     return false;
     280             : 
     281             :   // If any of the definitions are used by another instruction between the
     282             :   // position and the kill use, then it's not safe to sink it.
     283             :   //
     284             :   // FIXME: This can be sped up if there is an easy way to query whether an
     285             :   // instruction is before or after another instruction. Then we can use
     286             :   // MachineRegisterInfo def / use instead.
     287             :   MachineOperand *KillMO = nullptr;
     288             :   MachineBasicBlock::iterator KillPos = KillMI;
     289             :   ++KillPos;
     290             : 
     291             :   unsigned NumVisited = 0;
     292        6014 :   for (MachineInstr &OtherMI : make_range(std::next(OldPos), KillPos)) {
     293             :     // Debug instructions cannot be counted against the limit.
     294         151 :     if (OtherMI.isDebugInstr())
     295         151 :       continue;
     296        4173 :     if (NumVisited > 30)  // FIXME: Arbitrary limit to reduce compile time cost.
     297         830 :       return false;
     298        4169 :     ++NumVisited;
     299       22218 :     for (unsigned i = 0, e = OtherMI.getNumOperands(); i != e; ++i) {
     300       18875 :       MachineOperand &MO = OtherMI.getOperand(i);
     301       18875 :       if (!MO.isReg())
     302       13574 :         continue;
     303       13671 :       unsigned MOReg = MO.getReg();
     304       13671 :       if (!MOReg)
     305        3166 :         continue;
     306       10505 :       if (DefReg == MOReg)
     307         826 :         return false;
     308             : 
     309        9719 :       if (MO.isKill() || (LIS && isPlainlyKilled(&OtherMI, MOReg, LIS))) {
     310        2193 :         if (&OtherMI == KillMI && MOReg == SavedReg)
     311             :           // Save the operand that kills the register. We want to unset the kill
     312             :           // marker if we can sink MI past it.
     313             :           KillMO = &MO;
     314        1702 :         else if (UseRegs.count(MOReg))
     315             :           // One of the uses is killed before the destination.
     316             :           return false;
     317             :       }
     318             :     }
     319             :   }
     320             :   assert(KillMO && "Didn't find kill");
     321             : 
     322         430 :   if (!LIS) {
     323             :     // Update kill and LV information.
     324             :     KillMO->setIsKill(false);
     325         430 :     KillMO = MI->findRegisterUseOperand(SavedReg, false, TRI);
     326             :     KillMO->setIsKill(true);
     327             : 
     328         430 :     if (LV)
     329         430 :       LV->replaceKillInstruction(SavedReg, *KillMI, *MI);
     330             :   }
     331             : 
     332             :   // Move instruction to its destination.
     333         430 :   MBB->remove(MI);
     334         430 :   MBB->insert(KillPos, MI);
     335             : 
     336         430 :   if (LIS)
     337           0 :     LIS->handleMove(*MI);
     338             : 
     339             :   ++Num3AddrSunk;
     340             :   return true;
     341             : }
     342             : 
     343             : /// Return the MachineInstr* if it is the single def of the Reg in current BB.
     344       51698 : static MachineInstr *getSingleDef(unsigned Reg, MachineBasicBlock *BB,
     345             :                                   const MachineRegisterInfo *MRI) {
     346             :   MachineInstr *Ret = nullptr;
     347      101292 :   for (MachineInstr &DefMI : MRI->def_instructions(Reg)) {
     348      142399 :     if (DefMI.getParent() != BB || DefMI.isDebugValue())
     349        3705 :       continue;
     350       69347 :     if (!Ret)
     351             :       Ret = &DefMI;
     352       23458 :     else if (Ret != &DefMI)
     353             :       return nullptr;
     354             :   }
     355             :   return Ret;
     356             : }
     357             : 
     358             : /// Check if there is a reversed copy chain from FromReg to ToReg:
     359             : /// %Tmp1 = copy %Tmp2;
     360             : /// %FromReg = copy %Tmp1;
     361             : /// %ToReg = add %FromReg ...
     362             : /// %Tmp2 = copy %ToReg;
     363             : /// MaxLen specifies the maximum length of the copy chain the func
     364             : /// can walk through.
     365       42720 : bool TwoAddressInstructionPass::isRevCopyChain(unsigned FromReg, unsigned ToReg,
     366             :                                                int Maxlen) {
     367             :   unsigned TmpReg = FromReg;
     368       60960 :   for (int i = 0; i < Maxlen; i++) {
     369       51698 :     MachineInstr *Def = getSingleDef(TmpReg, MBB, MRI);
     370       74129 :     if (!Def || !Def->isCopy())
     371             :       return false;
     372             : 
     373        9324 :     TmpReg = Def->getOperand(1).getReg();
     374             : 
     375        9324 :     if (TmpReg == ToReg)
     376             :       return true;
     377             :   }
     378             :   return false;
     379             : }
     380             : 
     381             : /// Return true if there are no intervening uses between the last instruction
     382             : /// in the MBB that defines the specified register and the two-address
     383             : /// instruction which is being processed. It also returns the last def location
     384             : /// by reference.
     385       48594 : bool TwoAddressInstructionPass::noUseAfterLastDef(unsigned Reg, unsigned Dist,
     386             :                                                   unsigned &LastDef) {
     387       48594 :   LastDef = 0;
     388             :   unsigned LastUse = Dist;
     389      260783 :   for (MachineOperand &MO : MRI->reg_operands(Reg)) {
     390      163595 :     MachineInstr *MI = MO.getParent();
     391      321193 :     if (MI->getParent() != MBB || MI->isDebugValue())
     392       12339 :       continue;
     393      157440 :     DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(MI);
     394      157440 :     if (DI == DistanceMap.end())
     395          29 :       continue;
     396      157411 :     if (MO.isUse() && DI->second < LastUse)
     397             :       LastUse = DI->second;
     398      157411 :     if (MO.isDef() && DI->second > LastDef)
     399       69563 :       LastDef = DI->second;
     400             :   }
     401             : 
     402       48594 :   return !(LastUse > LastDef && LastUse < Dist);
     403             : }
     404             : 
     405             : /// Return true if the specified MI is a copy instruction or an extract_subreg
     406             : /// instruction. It also returns the source and destination registers and
     407             : /// whether they are physical registers by reference.
     408             : static bool isCopyToReg(MachineInstr &MI, const TargetInstrInfo *TII,
     409             :                         unsigned &SrcReg, unsigned &DstReg,
     410             :                         bool &IsSrcPhys, bool &IsDstPhys) {
     411             :   SrcReg = 0;
     412      890686 :   DstReg = 0;
     413     5918013 :   if (MI.isCopy()) {
     414     1635010 :     DstReg = MI.getOperand(0).getReg();
     415     1377824 :     SrcReg = MI.getOperand(1).getReg();
     416     4283003 :   } else if (MI.isInsertSubreg() || MI.isSubregToReg()) {
     417       92475 :     DstReg = MI.getOperand(0).getReg();
     418       66473 :     SrcReg = MI.getOperand(2).getReg();
     419             :   } else
     420             :     return false;
     421             : 
     422             :   IsSrcPhys = TargetRegisterInfo::isPhysicalRegister(SrcReg);
     423      566376 :   IsDstPhys = TargetRegisterInfo::isPhysicalRegister(DstReg);
     424             :   return true;
     425             : }
     426             : 
     427             : /// Test if the given register value, which is used by the
     428             : /// given instruction, is killed by the given instruction.
     429      378350 : static bool isPlainlyKilled(MachineInstr *MI, unsigned Reg,
     430             :                             LiveIntervals *LIS) {
     431      378350 :   if (LIS && TargetRegisterInfo::isVirtualRegister(Reg) &&
     432           0 :       !LIS->isNotInMIMap(*MI)) {
     433             :     // FIXME: Sometimes tryInstructionTransform() will add instructions and
     434             :     // test whether they can be folded before keeping them. In this case it
     435             :     // sets a kill before recursively calling tryInstructionTransform() again.
     436             :     // If there is no interval available, we assume that this instruction is
     437             :     // one of those. A kill flag is manually inserted on the operand so the
     438             :     // check below will handle it.
     439           0 :     LiveInterval &LI = LIS->getInterval(Reg);
     440             :     // This is to match the kill flag version where undefs don't have kill
     441             :     // flags.
     442           0 :     if (!LI.hasAtLeastOneValue())
     443             :       return false;
     444             : 
     445           0 :     SlotIndex useIdx = LIS->getInstructionIndex(*MI);
     446           0 :     LiveInterval::const_iterator I = LI.find(useIdx);
     447             :     assert(I != LI.end() && "Reg must be live-in to use.");
     448           0 :     return !I->end.isBlock() && SlotIndex::isSameInstr(I->end, useIdx);
     449             :   }
     450             : 
     451      378350 :   return MI->killsRegister(Reg);
     452             : }
     453             : 
     454             : /// Test if the given register value, which is used by the given
     455             : /// instruction, is killed by the given instruction. This looks through
     456             : /// coalescable copies to see if the original value is potentially not killed.
     457             : ///
     458             : /// For example, in this code:
     459             : ///
     460             : ///   %reg1034 = copy %reg1024
     461             : ///   %reg1035 = copy killed %reg1025
     462             : ///   %reg1036 = add killed %reg1034, killed %reg1035
     463             : ///
     464             : /// %reg1034 is not considered to be killed, since it is copied from a
     465             : /// register which is not killed. Treating it as not killed lets the
     466             : /// normal heuristics commute the (two-address) add, which lets
     467             : /// coalescing eliminate the extra copy.
     468             : ///
     469             : /// If allowFalsePositives is true then likely kills are treated as kills even
     470             : /// if it can't be proven that they are kills.
     471      307724 : static bool isKilled(MachineInstr &MI, unsigned Reg,
     472             :                      const MachineRegisterInfo *MRI,
     473             :                      const TargetInstrInfo *TII,
     474             :                      LiveIntervals *LIS,
     475             :                      bool allowFalsePositives) {
     476             :   MachineInstr *DefMI = &MI;
     477             :   while (true) {
     478             :     // All uses of physical registers are likely to be kills.
     479      376866 :     if (TargetRegisterInfo::isPhysicalRegister(Reg) &&
     480        8935 :         (allowFalsePositives || MRI->hasOneUse(Reg)))
     481      307724 :       return true;
     482      332809 :     if (!isPlainlyKilled(DefMI, Reg, LIS))
     483             :       return false;
     484      285134 :     if (TargetRegisterInfo::isPhysicalRegister(Reg))
     485             :       return true;
     486      282463 :     MachineRegisterInfo::def_iterator Begin = MRI->def_begin(Reg);
     487             :     // If there are multiple defs, we can't do a simple analysis, so just
     488             :     // go with what the kill flag says.
     489      282463 :     if (std::next(Begin) != MRI->def_end())
     490             :       return true;
     491      213088 :     DefMI = Begin->getParent();
     492             :     bool IsSrcPhys, IsDstPhys;
     493             :     unsigned SrcReg,  DstReg;
     494             :     // If the def is something other than a copy, then it isn't going to
     495             :     // be coalesced, so follow the kill flag.
     496      213088 :     if (!isCopyToReg(*DefMI, TII, SrcReg, DstReg, IsSrcPhys, IsDstPhys))
     497             :       return true;
     498             :     Reg = SrcReg;
     499       69142 :   }
     500             : }
     501             : 
     502             : /// Return true if the specified MI uses the specified register as a two-address
     503             : /// use. If so, return the destination register by reference.
     504      644784 : static bool isTwoAddrUse(MachineInstr &MI, unsigned Reg, unsigned &DstReg) {
     505     3295362 :   for (unsigned i = 0, NumOps = MI.getNumOperands(); i != NumOps; ++i) {
     506     2815531 :     const MachineOperand &MO = MI.getOperand(i);
     507     4863961 :     if (!MO.isReg() || !MO.isUse() || MO.getReg() != Reg)
     508     2163563 :       continue;
     509             :     unsigned ti;
     510      651968 :     if (MI.isRegTiedToDefOperand(i, &ti)) {
     511      329906 :       DstReg = MI.getOperand(ti).getReg();
     512      164953 :       return true;
     513             :     }
     514             :   }
     515             :   return false;
     516             : }
     517             : 
     518             : /// Given a register, if has a single in-basic block use, return the use
     519             : /// instruction if it's a copy or a two-address use.
     520             : static
     521     1080785 : MachineInstr *findOnlyInterestingUse(unsigned Reg, MachineBasicBlock *MBB,
     522             :                                      MachineRegisterInfo *MRI,
     523             :                                      const TargetInstrInfo *TII,
     524             :                                      bool &IsCopy,
     525             :                                      unsigned &DstReg, bool &IsDstPhys) {
     526     1080785 :   if (!MRI->hasOneNonDBGUse(Reg))
     527             :     // None or more than one use.
     528             :     return nullptr;
     529     1860046 :   MachineInstr &UseMI = *MRI->use_instr_nodbg_begin(Reg);
     530      930023 :   if (UseMI.getParent() != MBB)
     531             :     return nullptr;
     532             :   unsigned SrcReg;
     533             :   bool IsSrcPhys;
     534             :   if (isCopyToReg(UseMI, TII, SrcReg, DstReg, IsSrcPhys, IsDstPhys)) {
     535      283188 :     IsCopy = true;
     536             :     return &UseMI;
     537             :   }
     538      607498 :   IsDstPhys = false;
     539      607498 :   if (isTwoAddrUse(UseMI, Reg, DstReg)) {
     540      290188 :     IsDstPhys = TargetRegisterInfo::isPhysicalRegister(DstReg);
     541             :     return &UseMI;
     542             :   }
     543             :   return nullptr;
     544             : }
     545             : 
     546             : /// Return the physical register the specified virtual register might be mapped
     547             : /// to.
     548             : static unsigned
     549      107084 : getMappedReg(unsigned Reg, DenseMap<unsigned, unsigned> &RegMap) {
     550      554545 :   while (TargetRegisterInfo::isVirtualRegister(Reg))  {
     551      179192 :     DenseMap<unsigned, unsigned>::iterator SI = RegMap.find(Reg);
     552      179192 :     if (SI == RegMap.end())
     553       65733 :       return 0;
     554      113459 :     Reg = SI->second;
     555             :   }
     556       41351 :   if (TargetRegisterInfo::isPhysicalRegister(Reg))
     557       41351 :     return Reg;
     558             :   return 0;
     559             : }
     560             : 
     561             : /// Return true if the two registers are equal or aliased.
     562             : static bool
     563             : regsAreCompatible(unsigned RegA, unsigned RegB, const TargetRegisterInfo *TRI) {
     564       18241 :   if (RegA == RegB)
     565             :     return true;
     566             :   if (!RegA || !RegB)
     567             :     return false;
     568        9033 :   return TRI->regsOverlap(RegA, RegB);
     569             : }
     570             : 
     571             : // Returns true if Reg is equal or aliased to at least one register in Set.
     572             : static bool regOverlapsSet(const SmallVectorImpl<unsigned> &Set, unsigned Reg,
     573             :                            const TargetRegisterInfo *TRI) {
     574      176836 :   for (unsigned R : Set)
     575       69279 :     if (TRI->regsOverlap(R, Reg))
     576             :       return true;
     577             : 
     578             :   return false;
     579             : }
     580             : 
     581             : /// Return true if it's potentially profitable to commute the two-address
     582             : /// instruction that's being processed.
     583             : bool
     584       45541 : TwoAddressInstructionPass::
     585             : isProfitableToCommute(unsigned regA, unsigned regB, unsigned regC,
     586             :                       MachineInstr *MI, unsigned Dist) {
     587       45541 :   if (OptLevel == CodeGenOpt::None)
     588             :     return false;
     589             : 
     590             :   // Determine if it's profitable to commute this two address instruction. In
     591             :   // general, we want no uses between this instruction and the definition of
     592             :   // the two-address register.
     593             :   // e.g.
     594             :   // %reg1028 = EXTRACT_SUBREG killed %reg1027, 1
     595             :   // %reg1029 = MOV8rr %reg1028
     596             :   // %reg1029 = SHR8ri %reg1029, 7, implicit dead %eflags
     597             :   // insert => %reg1030 = MOV8rr %reg1028
     598             :   // %reg1030 = ADD8rr killed %reg1028, killed %reg1029, implicit dead %eflags
     599             :   // In this case, it might not be possible to coalesce the second MOV8rr
     600             :   // instruction if the first one is coalesced. So it would be profitable to
     601             :   // commute it:
     602             :   // %reg1028 = EXTRACT_SUBREG killed %reg1027, 1
     603             :   // %reg1029 = MOV8rr %reg1028
     604             :   // %reg1029 = SHR8ri %reg1029, 7, implicit dead %eflags
     605             :   // insert => %reg1030 = MOV8rr %reg1029
     606             :   // %reg1030 = ADD8rr killed %reg1029, killed %reg1028, implicit dead %eflags
     607             : 
     608       45541 :   if (!isPlainlyKilled(MI, regC, LIS))
     609             :     return false;
     610             : 
     611             :   // Ok, we have something like:
     612             :   // %reg1030 = ADD8rr killed %reg1028, killed %reg1029, implicit dead %eflags
     613             :   // let's see if it's worth commuting it.
     614             : 
     615             :   // Look for situations like this:
     616             :   // %reg1024 = MOV r1
     617             :   // %reg1025 = MOV r0
     618             :   // %reg1026 = ADD %reg1024, %reg1025
     619             :   // r0            = MOV %reg1026
     620             :   // Commute the ADD to hopefully eliminate an otherwise unavoidable copy.
     621       33486 :   unsigned ToRegA = getMappedReg(regA, DstRegMap);
     622       33486 :   if (ToRegA) {
     623       13315 :     unsigned FromRegB = getMappedReg(regB, SrcRegMap);
     624       13315 :     unsigned FromRegC = getMappedReg(regC, SrcRegMap);
     625       16046 :     bool CompB = FromRegB && regsAreCompatible(FromRegB, ToRegA, TRI);
     626       18705 :     bool CompC = FromRegC && regsAreCompatible(FromRegC, ToRegA, TRI);
     627             : 
     628             :     // Compute if any of the following are true:
     629             :     // -RegB is not tied to a register and RegC is compatible with RegA.
     630             :     // -RegB is tied to the wrong physical register, but RegC is.
     631             :     // -RegB is tied to the wrong physical register, and RegC isn't tied.
     632       13315 :     if ((!FromRegB && CompC) || (FromRegB && !CompB && (!FromRegC || CompC)))
     633             :       return true;
     634             :     // Don't compute if any of the following are true:
     635             :     // -RegC is not tied to a register and RegB is compatible with RegA.
     636             :     // -RegC is tied to the wrong physical register, but RegB is.
     637             :     // -RegC is tied to the wrong physical register, and RegB isn't tied.
     638       11396 :     if ((!FromRegC && CompB) || (FromRegC && !CompC && (!FromRegB || CompB)))
     639             :       return false;
     640             :   }
     641             : 
     642             :   // If there is a use of regC between its last def (could be livein) and this
     643             :   // instruction, then bail.
     644       25738 :   unsigned LastDefC = 0;
     645       25738 :   if (!noUseAfterLastDef(regC, Dist, LastDefC))
     646             :     return false;
     647             : 
     648             :   // If there is a use of regB between its last def (could be livein) and this
     649             :   // instruction, then go ahead and make this transformation.
     650       22856 :   unsigned LastDefB = 0;
     651       22856 :   if (!noUseAfterLastDef(regB, Dist, LastDefB))
     652             :     return true;
     653             : 
     654             :   // Look for situation like this:
     655             :   // %reg101 = MOV %reg100
     656             :   // %reg102 = ...
     657             :   // %reg103 = ADD %reg102, %reg101
     658             :   // ... = %reg103 ...
     659             :   // %reg100 = MOV %reg103
     660             :   // If there is a reversed copy chain from reg101 to reg103, commute the ADD
     661             :   // to eliminate an otherwise unavoidable copy.
     662             :   // FIXME:
     663             :   // We can extend the logic further: If an pair of operands in an insn has
     664             :   // been merged, the insn could be regarded as a virtual copy, and the virtual
     665             :   // copy could also be used to construct a copy chain.
     666             :   // To more generally minimize register copies, ideally the logic of two addr
     667             :   // instruction pass should be integrated with register allocation pass where
     668             :   // interference graph is available.
     669       21375 :   if (isRevCopyChain(regC, regA, MaxDataFlowEdge))
     670             :     return true;
     671             : 
     672       21345 :   if (isRevCopyChain(regB, regA, MaxDataFlowEdge))
     673             :     return false;
     674             : 
     675             :   // Since there are no intervening uses for both registers, then commute
     676             :   // if the def of regC is closer. Its live interval is shorter.
     677       21171 :   return LastDefB && LastDefC && LastDefC > LastDefB;
     678             : }
     679             : 
     680             : /// Commute a two-address instruction and update the basic block, distance map,
     681             : /// and live variables if needed. Return true if it is successful.
     682       18407 : bool TwoAddressInstructionPass::commuteInstruction(MachineInstr *MI,
     683             :                                                    unsigned DstIdx,
     684             :                                                    unsigned RegBIdx,
     685             :                                                    unsigned RegCIdx,
     686             :                                                    unsigned Dist) {
     687       36814 :   unsigned RegC = MI->getOperand(RegCIdx).getReg();
     688             :   LLVM_DEBUG(dbgs() << "2addr: COMMUTING  : " << *MI);
     689       18407 :   MachineInstr *NewMI = TII->commuteInstruction(*MI, false, RegBIdx, RegCIdx);
     690             : 
     691       18407 :   if (NewMI == nullptr) {
     692             :     LLVM_DEBUG(dbgs() << "2addr: COMMUTING FAILED!\n");
     693             :     return false;
     694             :   }
     695             : 
     696             :   LLVM_DEBUG(dbgs() << "2addr: COMMUTED TO: " << *NewMI);
     697             :   assert(NewMI == MI &&
     698             :          "TargetInstrInfo::commuteInstruction() should not return a new "
     699             :          "instruction unless it was requested.");
     700             : 
     701             :   // Update source register map.
     702       18397 :   unsigned FromRegC = getMappedReg(RegC, SrcRegMap);
     703       18397 :   if (FromRegC) {
     704       10706 :     unsigned RegA = MI->getOperand(DstIdx).getReg();
     705        5353 :     SrcRegMap[RegA] = FromRegC;
     706             :   }
     707             : 
     708             :   return true;
     709             : }
     710             : 
     711             : /// Return true if it is profitable to convert the given 2-address instruction
     712             : /// to a 3-address one.
     713             : bool
     714       24129 : TwoAddressInstructionPass::isProfitableToConv3Addr(unsigned RegA,unsigned RegB){
     715             :   // Look for situations like this:
     716             :   // %reg1024 = MOV r1
     717             :   // %reg1025 = MOV r0
     718             :   // %reg1026 = ADD %reg1024, %reg1025
     719             :   // r2            = MOV %reg1026
     720             :   // Turn ADD into a 3-address instruction to avoid a copy.
     721       24129 :   unsigned FromRegB = getMappedReg(RegB, SrcRegMap);
     722       24129 :   if (!FromRegB)
     723             :     return false;
     724        4442 :   unsigned ToRegA = getMappedReg(RegA, DstRegMap);
     725        5354 :   return (ToRegA && !regsAreCompatible(FromRegB, ToRegA, TRI));
     726             : }
     727             : 
     728             : /// Convert the specified two-address instruction into a three address one.
     729             : /// Return true if this transformation was successful.
     730             : bool
     731        7260 : TwoAddressInstructionPass::convertInstTo3Addr(MachineBasicBlock::iterator &mi,
     732             :                                               MachineBasicBlock::iterator &nmi,
     733             :                                               unsigned RegA, unsigned RegB,
     734             :                                               unsigned Dist) {
     735             :   // FIXME: Why does convertToThreeAddress() need an iterator reference?
     736        7260 :   MachineFunction::iterator MFI = MBB->getIterator();
     737       14520 :   MachineInstr *NewMI = TII->convertToThreeAddress(MFI, *mi, LV);
     738             :   assert(MBB->getIterator() == MFI &&
     739             :          "convertToThreeAddress changed iterator reference");
     740        7260 :   if (!NewMI)
     741             :     return false;
     742             : 
     743             :   LLVM_DEBUG(dbgs() << "2addr: CONVERTING 2-ADDR: " << *mi);
     744             :   LLVM_DEBUG(dbgs() << "2addr:         TO 3-ADDR: " << *NewMI);
     745             :   bool Sunk = false;
     746             : 
     747        5905 :   if (LIS)
     748           0 :     LIS->ReplaceMachineInstrInMaps(*mi, *NewMI);
     749             : 
     750       10989 :   if (NewMI->findRegisterUseOperand(RegB, false, TRI))
     751             :     // FIXME: Temporary workaround. If the new instruction doesn't
     752             :     // uses RegB, convertToThreeAddress must have created more
     753             :     // then one instruction.
     754        5084 :     Sunk = sink3AddrInstruction(NewMI, RegB, mi);
     755             : 
     756        5905 :   MBB->erase(mi); // Nuke the old inst.
     757             : 
     758        5905 :   if (!Sunk) {
     759       10950 :     DistanceMap.insert(std::make_pair(NewMI, Dist));
     760        5475 :     mi = NewMI;
     761        5475 :     nmi = std::next(mi);
     762             :   }
     763             :   else
     764         430 :     SunkInstrs.insert(NewMI);
     765             : 
     766             :   // Update source and destination register maps.
     767        5905 :   SrcRegMap.erase(RegA);
     768        5905 :   DstRegMap.erase(RegB);
     769        5905 :   return true;
     770             : }
     771             : 
     772             : /// Scan forward recursively for only uses, update maps if the use is a copy or
     773             : /// a two-address instruction.
     774             : void
     775      762491 : TwoAddressInstructionPass::scanUses(unsigned DstReg) {
     776             :   SmallVector<unsigned, 4> VirtRegPairs;
     777             :   bool IsDstPhys;
     778      762491 :   bool IsCopy = false;
     779      762491 :   unsigned NewReg = 0;
     780             :   unsigned Reg = DstReg;
     781     1080785 :   while (MachineInstr *UseMI = findOnlyInterestingUse(Reg, MBB, MRI, TII,IsCopy,
     782     1080785 :                                                       NewReg, IsDstPhys)) {
     783      428282 :     if (IsCopy && !Processed.insert(UseMI).second)
     784             :       break;
     785             : 
     786      392965 :     DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(UseMI);
     787      392965 :     if (DI != DistanceMap.end())
     788             :       // Earlier in the same MBB.Reached via a back edge.
     789             :       break;
     790             : 
     791      392965 :     if (IsDstPhys) {
     792       74671 :       VirtRegPairs.push_back(NewReg);
     793       74671 :       break;
     794             :     }
     795      636588 :     bool isNew = SrcRegMap.insert(std::make_pair(NewReg, Reg)).second;
     796             :     if (!isNew)
     797             :       assert(SrcRegMap[NewReg] == Reg && "Can't map to two src registers!");
     798      318294 :     VirtRegPairs.push_back(NewReg);
     799      318294 :     Reg = NewReg;
     800             :   }
     801             : 
     802      762491 :   if (!VirtRegPairs.empty()) {
     803      251265 :     unsigned ToReg = VirtRegPairs.back();
     804             :     VirtRegPairs.pop_back();
     805      534665 :     while (!VirtRegPairs.empty()) {
     806      141700 :       unsigned FromReg = VirtRegPairs.back();
     807             :       VirtRegPairs.pop_back();
     808      283400 :       bool isNew = DstRegMap.insert(std::make_pair(FromReg, ToReg)).second;
     809             :       if (!isNew)
     810             :         assert(DstRegMap[FromReg] == ToReg &&"Can't map to two dst registers!");
     811             :       ToReg = FromReg;
     812             :     }
     813      502530 :     bool isNew = DstRegMap.insert(std::make_pair(DstReg, ToReg)).second;
     814             :     if (!isNew)
     815             :       assert(DstRegMap[DstReg] == ToReg && "Can't map to two dst registers!");
     816             :   }
     817      762491 : }
     818             : 
     819             : /// If the specified instruction is not yet processed, process it if it's a
     820             : /// copy. For a copy instruction, we find the physical registers the
     821             : /// source and destination registers might be mapped to. These are kept in
     822             : /// point-to maps used to determine future optimizations. e.g.
     823             : /// v1024 = mov r0
     824             : /// v1025 = mov r1
     825             : /// v1026 = add v1024, v1025
     826             : /// r1    = mov r1026
     827             : /// If 'add' is a two-address instruction, v1024, v1026 are both potentially
     828             : /// coalesced to r0 (from the input side). v1025 is mapped to r1. v1026 is
     829             : /// potentially joined with r1 on the output side. It's worthwhile to commute
     830             : /// 'add' to eliminate a copy.
     831     5066833 : void TwoAddressInstructionPass::processCopy(MachineInstr *MI) {
     832     5066833 :   if (Processed.count(MI))
     833             :     return;
     834             : 
     835             :   bool IsSrcPhys, IsDstPhys;
     836             :   unsigned SrcReg, DstReg;
     837     4814239 :   if (!isCopyToReg(*MI, TII, SrcReg, DstReg, IsSrcPhys, IsDstPhys))
     838             :     return;
     839             : 
     840     1375155 :   if (IsDstPhys && !IsSrcPhys)
     841     1034450 :     DstRegMap.insert(std::make_pair(SrcReg, DstReg));
     842      857930 :   else if (!IsDstPhys && IsSrcPhys) {
     843     1015124 :     bool isNew = SrcRegMap.insert(std::make_pair(DstReg, SrcReg)).second;
     844             :     if (!isNew)
     845             :       assert(SrcRegMap[DstReg] == SrcReg &&
     846             :              "Can't map to two src physical registers!");
     847             : 
     848      507562 :     scanUses(DstReg);
     849             :   }
     850             : 
     851     1375155 :   Processed.insert(MI);
     852             : }
     853             : 
     854             : /// If there is one more local instruction that reads 'Reg' and it kills 'Reg,
     855             : /// consider moving the instruction below the kill instruction in order to
     856             : /// eliminate the need for the copy.
     857      236400 : bool TwoAddressInstructionPass::
     858             : rescheduleMIBelowKill(MachineBasicBlock::iterator &mi,
     859             :                       MachineBasicBlock::iterator &nmi,
     860             :                       unsigned Reg) {
     861             :   // Bail immediately if we don't have LV or LIS available. We use them to find
     862             :   // kills efficiently.
     863      236400 :   if (!LV && !LIS)
     864             :     return false;
     865             : 
     866             :   MachineInstr *MI = &*mi;
     867      236372 :   DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(MI);
     868      236372 :   if (DI == DistanceMap.end())
     869             :     // Must be created from unfolded load. Don't waste time trying this.
     870             :     return false;
     871             : 
     872             :   MachineInstr *KillMI = nullptr;
     873      236372 :   if (LIS) {
     874           0 :     LiveInterval &LI = LIS->getInterval(Reg);
     875             :     assert(LI.end() != LI.begin() &&
     876             :            "Reg should not have empty live interval.");
     877             : 
     878           0 :     SlotIndex MBBEndIdx = LIS->getMBBEndIdx(MBB).getPrevSlot();
     879           0 :     LiveInterval::const_iterator I = LI.find(MBBEndIdx);
     880           0 :     if (I != LI.end() && I->start < MBBEndIdx)
     881             :       return false;
     882             : 
     883             :     --I;
     884             :     KillMI = LIS->getInstructionFromIndex(I->end);
     885             :   } else {
     886      236372 :     KillMI = LV->getVarInfo(Reg).findKill(MBB);
     887             :   }
     888      257911 :   if (!KillMI || MI == KillMI || KillMI->isCopy() || KillMI->isCopyLike())
     889             :     // Don't mess with copies, they may be coalesced later.
     890             :     return false;
     891             : 
     892       60002 :   if (KillMI->hasUnmodeledSideEffects() || KillMI->isCall() ||
     893       40006 :       KillMI->isBranch() || KillMI->isTerminator())
     894             :     // Don't move pass calls, etc.
     895             :     return false;
     896             : 
     897             :   unsigned DstReg;
     898       19996 :   if (isTwoAddrUse(*KillMI, Reg, DstReg))
     899             :     return false;
     900             : 
     901        9866 :   bool SeenStore = true;
     902        9866 :   if (!MI->isSafeToMove(AA, SeenStore))
     903             :     return false;
     904             : 
     905        9327 :   if (TII->getInstrLatency(InstrItins, *MI) > 1)
     906             :     // FIXME: Needs more sophisticated heuristics.
     907             :     return false;
     908             : 
     909             :   SmallVector<unsigned, 2> Uses;
     910             :   SmallVector<unsigned, 2> Kills;
     911             :   SmallVector<unsigned, 2> Defs;
     912       76995 :   for (const MachineOperand &MO : MI->operands()) {
     913       33901 :     if (!MO.isReg())
     914       11291 :       continue;
     915       28274 :     unsigned MOReg = MO.getReg();
     916       28274 :     if (!MOReg)
     917          37 :       continue;
     918       28237 :     if (MO.isDef())
     919       14948 :       Defs.push_back(MOReg);
     920             :     else {
     921       13289 :       Uses.push_back(MOReg);
     922       19819 :       if (MOReg != Reg && (MO.isKill() ||
     923        2626 :                            (LIS && isPlainlyKilled(MI, MOReg, LIS))))
     924        1278 :         Kills.push_back(MOReg);
     925             :     }
     926             :   }
     927             : 
     928             :   // Move the copies connected to MI down as well.
     929             :   MachineBasicBlock::iterator Begin = MI;
     930             :   MachineBasicBlock::iterator AfterMI = std::next(Begin);
     931        9193 :   MachineBasicBlock::iterator End = AfterMI;
     932        9735 :   while (End->isCopy() &&
     933         331 :          regOverlapsSet(Defs, End->getOperand(1).getReg(), TRI)) {
     934         211 :     Defs.push_back(End->getOperand(0).getReg());
     935             :     ++End;
     936             :   }
     937             : 
     938             :   // Check if the reschedule will not break dependencies.
     939             :   unsigned NumVisited = 0;
     940             :   MachineBasicBlock::iterator KillPos = KillMI;
     941             :   ++KillPos;
     942       23647 :   for (MachineInstr &OtherMI : make_range(End, KillPos)) {
     943             :     // Debug instructions cannot be counted against the limit.
     944         117 :     if (OtherMI.isDebugInstr())
     945         117 :       continue;
     946       12910 :     if (NumVisited > 10)  // FIXME: Arbitrary limit to reduce compile time cost.
     947        7766 :       return false;
     948       12844 :     ++NumVisited;
     949       38499 :     if (OtherMI.hasUnmodeledSideEffects() || OtherMI.isCall() ||
     950       25657 :         OtherMI.isBranch() || OtherMI.isTerminator())
     951             :       // Don't move pass calls, etc.
     952             :       return false;
     953       75025 :     for (const MachineOperand &MO : OtherMI.operands()) {
     954       38775 :       if (!MO.isReg())
     955        5704 :         continue;
     956       33071 :       unsigned MOReg = MO.getReg();
     957       33071 :       if (!MOReg)
     958        3678 :         continue;
     959       29393 :       if (MO.isDef()) {
     960       24946 :         if (regOverlapsSet(Uses, MOReg, TRI))
     961             :           // Physical register use would be clobbered.
     962             :           return false;
     963       23632 :         if (!MO.isDead() && regOverlapsSet(Defs, MOReg, TRI))
     964             :           // May clobber a physical register def.
     965             :           // FIXME: This may be too conservative. It's ok if the instruction
     966             :           // is sunken completely below the use.
     967             :           return false;
     968             :       } else {
     969       33840 :         if (regOverlapsSet(Defs, MOReg, TRI))
     970             :           return false;
     971             :         bool isKill =
     972       10763 :             MO.isKill() || (LIS && isPlainlyKilled(&OtherMI, MOReg, LIS));
     973       22955 :         if (MOReg != Reg && ((isKill && regOverlapsSet(Uses, MOReg, TRI)) ||
     974        7920 :                              regOverlapsSet(Kills, MOReg, TRI)))
     975             :           // Don't want to extend other live ranges and update kills.
     976             :           return false;
     977       10083 :         if (MOReg == Reg && !isKill)
     978             :           // We can't schedule across a use of the register in question.
     979             :           return false;
     980             :         // Ensure that if this is register in question, its the kill we expect.
     981             :         assert((MOReg != Reg || &OtherMI == KillMI) &&
     982             :                "Found multiple kills of a register in a basic block");
     983             :       }
     984             :     }
     985             :   }
     986             : 
     987             :   // Move debug info as well.
     988        3130 :   while (Begin != MBB->begin() && std::prev(Begin)->isDebugInstr())
     989             :     --Begin;
     990             : 
     991        1427 :   nmi = End;
     992        1427 :   MachineBasicBlock::iterator InsertPos = KillPos;
     993        1427 :   if (LIS) {
     994             :     // We have to move the copies first so that the MBB is still well-formed
     995             :     // when calling handleMove().
     996           0 :     for (MachineBasicBlock::iterator MBBI = AfterMI; MBBI != End;) {
     997             :       auto CopyMI = MBBI++;
     998           0 :       MBB->splice(InsertPos, MBB, CopyMI);
     999           0 :       LIS->handleMove(*CopyMI);
    1000             :       InsertPos = CopyMI;
    1001             :     }
    1002           0 :     End = std::next(MachineBasicBlock::iterator(MI));
    1003             :   }
    1004             : 
    1005             :   // Copies following MI may have been moved as well.
    1006        1427 :   MBB->splice(InsertPos, MBB, Begin, End);
    1007             :   DistanceMap.erase(DI);
    1008             : 
    1009             :   // Update live variables
    1010        1427 :   if (LIS) {
    1011           0 :     LIS->handleMove(*MI);
    1012             :   } else {
    1013        1427 :     LV->removeVirtualRegisterKilled(Reg, *KillMI);
    1014        1427 :     LV->addVirtualRegisterKilled(Reg, *MI);
    1015             :   }
    1016             : 
    1017             :   LLVM_DEBUG(dbgs() << "\trescheduled below kill: " << *KillMI);
    1018             :   return true;
    1019             : }
    1020             : 
    1021             : /// Return true if the re-scheduling will put the given instruction too close
    1022             : /// to the defs of its register dependencies.
    1023       12480 : bool TwoAddressInstructionPass::isDefTooClose(unsigned Reg, unsigned Dist,
    1024             :                                               MachineInstr *MI) {
    1025       38628 :   for (MachineInstr &DefMI : MRI->def_instructions(Reg)) {
    1026       36673 :     if (DefMI.getParent() != MBB || DefMI.isCopy() || DefMI.isCopyLike())
    1027       12141 :       continue;
    1028        3314 :     if (&DefMI == MI)
    1029        1787 :       return true; // MI is defining something KillMI uses
    1030        2817 :     DenseMap<MachineInstr*, unsigned>::iterator DDI = DistanceMap.find(&DefMI);
    1031        2817 :     if (DDI == DistanceMap.end())
    1032             :       return true;  // Below MI
    1033        1685 :     unsigned DefDist = DDI->second;
    1034             :     assert(Dist > DefDist && "Visited def already?");
    1035        1685 :     if (TII->getInstrLatency(InstrItins, DefMI) > (Dist - DefDist))
    1036             :       return true;
    1037             :   }
    1038             :   return false;
    1039             : }
    1040             : 
    1041             : /// If there is one more local instruction that reads 'Reg' and it kills 'Reg,
    1042             : /// consider moving the kill instruction above the current two-address
    1043             : /// instruction in order to eliminate the need for the copy.
    1044      229185 : bool TwoAddressInstructionPass::
    1045             : rescheduleKillAboveMI(MachineBasicBlock::iterator &mi,
    1046             :                       MachineBasicBlock::iterator &nmi,
    1047             :                       unsigned Reg) {
    1048             :   // Bail immediately if we don't have LV or LIS available. We use them to find
    1049             :   // kills efficiently.
    1050      229185 :   if (!LV && !LIS)
    1051             :     return false;
    1052             : 
    1053             :   MachineInstr *MI = &*mi;
    1054      229166 :   DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(MI);
    1055      229166 :   if (DI == DistanceMap.end())
    1056             :     // Must be created from unfolded load. Don't waste time trying this.
    1057             :     return false;
    1058             : 
    1059             :   MachineInstr *KillMI = nullptr;
    1060      229166 :   if (LIS) {
    1061           0 :     LiveInterval &LI = LIS->getInterval(Reg);
    1062             :     assert(LI.end() != LI.begin() &&
    1063             :            "Reg should not have empty live interval.");
    1064             : 
    1065           0 :     SlotIndex MBBEndIdx = LIS->getMBBEndIdx(MBB).getPrevSlot();
    1066           0 :     LiveInterval::const_iterator I = LI.find(MBBEndIdx);
    1067           0 :     if (I != LI.end() && I->start < MBBEndIdx)
    1068             :       return false;
    1069             : 
    1070             :     --I;
    1071             :     KillMI = LIS->getInstructionFromIndex(I->end);
    1072             :   } else {
    1073      229166 :     KillMI = LV->getVarInfo(Reg).findKill(MBB);
    1074             :   }
    1075      247505 :   if (!KillMI || MI == KillMI || KillMI->isCopy() || KillMI->isCopyLike())
    1076             :     // Don't mess with copies, they may be coalesced later.
    1077             :     return false;
    1078             : 
    1079             :   unsigned DstReg;
    1080       17290 :   if (isTwoAddrUse(*KillMI, Reg, DstReg))
    1081             :     return false;
    1082             : 
    1083        7561 :   bool SeenStore = true;
    1084        7561 :   if (!KillMI->isSafeToMove(AA, SeenStore))
    1085             :     return false;
    1086             : 
    1087        7012 :   SmallSet<unsigned, 2> Uses;
    1088        7012 :   SmallSet<unsigned, 2> Kills;
    1089        7012 :   SmallSet<unsigned, 2> Defs;
    1090        7012 :   SmallSet<unsigned, 2> LiveDefs;
    1091       29598 :   for (const MachineOperand &MO : KillMI->operands()) {
    1092       16646 :     if (!MO.isReg())
    1093        1070 :       continue;
    1094       16149 :     unsigned MOReg = MO.getReg();
    1095       16149 :     if (MO.isUse()) {
    1096       12556 :       if (!MOReg)
    1097          76 :         continue;
    1098       12480 :       if (isDefTooClose(MOReg, DI->second, MI))
    1099        5353 :         return false;
    1100       10693 :       bool isKill = MO.isKill() || (LIS && isPlainlyKilled(KillMI, MOReg, LIS));
    1101       10693 :       if (MOReg == Reg && !isKill)
    1102             :         return false;
    1103        7127 :       Uses.insert(MOReg);
    1104        7127 :       if (isKill && MOReg != Reg)
    1105        1404 :         Kills.insert(MOReg);
    1106        3593 :     } else if (TargetRegisterInfo::isPhysicalRegister(MOReg)) {
    1107         559 :       Defs.insert(MOReg);
    1108         559 :       if (!MO.isDead())
    1109         357 :         LiveDefs.insert(MOReg);
    1110             :     }
    1111             :   }
    1112             : 
    1113             :   // Check if the reschedule will not break depedencies.
    1114             :   unsigned NumVisited = 0;
    1115             :   for (MachineInstr &OtherMI :
    1116        9189 :        make_range(mi, MachineBasicBlock::iterator(KillMI))) {
    1117             :     // Debug instructions cannot be counted against the limit.
    1118           0 :     if (OtherMI.isDebugInstr())
    1119           0 :       continue;
    1120        7263 :     if (NumVisited > 10)  // FIXME: Arbitrary limit to reduce compile time cost.
    1121        1392 :       return false;
    1122        7003 :     ++NumVisited;
    1123       20974 :     if (OtherMI.hasUnmodeledSideEffects() || OtherMI.isCall() ||
    1124       13973 :         OtherMI.isBranch() || OtherMI.isTerminator())
    1125             :       // Don't move pass calls, etc.
    1126             :       return false;
    1127             :     SmallVector<unsigned, 2> OtherDefs;
    1128       57702 :     for (const MachineOperand &MO : OtherMI.operands()) {
    1129       26106 :       if (!MO.isReg())
    1130       14481 :         continue;
    1131       20556 :       unsigned MOReg = MO.getReg();
    1132       20556 :       if (!MOReg)
    1133        3381 :         continue;
    1134       17175 :       if (MO.isUse()) {
    1135       10342 :         if (Defs.count(MOReg))
    1136             :           // Moving KillMI can clobber the physical register if the def has
    1137             :           // not been seen.
    1138         740 :           return false;
    1139       10325 :         if (Kills.count(MOReg))
    1140             :           // Don't want to extend other live ranges and update kills.
    1141             :           return false;
    1142        9994 :         if (&OtherMI != MI && MOReg == Reg &&
    1143         196 :             !(MO.isKill() || (LIS && isPlainlyKilled(&OtherMI, MOReg, LIS))))
    1144             :           // We can't schedule across a use of the register in question.
    1145             :           return false;
    1146             :       } else {
    1147        6833 :         OtherDefs.push_back(MOReg);
    1148             :       }
    1149             :     }
    1150             : 
    1151       11929 :     for (unsigned i = 0, e = OtherDefs.size(); i != e; ++i) {
    1152       12116 :       unsigned MOReg = OtherDefs[i];
    1153        6058 :       if (Uses.count(MOReg))
    1154         359 :         return false;
    1155        6650 :       if (TargetRegisterInfo::isPhysicalRegister(MOReg) &&
    1156         766 :           LiveDefs.count(MOReg))
    1157             :         return false;
    1158             :       // Physical register def is seen.
    1159        5699 :       Defs.erase(MOReg);
    1160             :     }
    1161             :   }
    1162             : 
    1163             :   // Move the old kill above MI, don't forget to move debug info as well.
    1164         267 :   MachineBasicBlock::iterator InsertPos = mi;
    1165         534 :   while (InsertPos != MBB->begin() && std::prev(InsertPos)->isDebugInstr())
    1166             :     --InsertPos;
    1167             :   MachineBasicBlock::iterator From = KillMI;
    1168             :   MachineBasicBlock::iterator To = std::next(From);
    1169             :   while (std::prev(From)->isDebugInstr())
    1170             :     --From;
    1171         267 :   MBB->splice(InsertPos, MBB, From, To);
    1172             : 
    1173         267 :   nmi = std::prev(InsertPos); // Backtrack so we process the moved instr.
    1174             :   DistanceMap.erase(DI);
    1175             : 
    1176             :   // Update live variables
    1177         267 :   if (LIS) {
    1178           0 :     LIS->handleMove(*KillMI);
    1179             :   } else {
    1180         267 :     LV->removeVirtualRegisterKilled(Reg, *KillMI);
    1181         267 :     LV->addVirtualRegisterKilled(Reg, *MI);
    1182             :   }
    1183             : 
    1184             :   LLVM_DEBUG(dbgs() << "\trescheduled kill: " << *KillMI);
    1185             :   return true;
    1186             : }
    1187             : 
    1188             : /// Tries to commute the operand 'BaseOpIdx' and some other operand in the
    1189             : /// given machine instruction to improve opportunities for coalescing and
    1190             : /// elimination of a register to register copy.
    1191             : ///
    1192             : /// 'DstOpIdx' specifies the index of MI def operand.
    1193             : /// 'BaseOpKilled' specifies if the register associated with 'BaseOpIdx'
    1194             : /// operand is killed by the given instruction.
    1195             : /// The 'Dist' arguments provides the distance of MI from the start of the
    1196             : /// current basic block and it is used to determine if it is profitable
    1197             : /// to commute operands in the instruction.
    1198             : ///
    1199             : /// Returns true if the transformation happened. Otherwise, returns false.
    1200      254959 : bool TwoAddressInstructionPass::tryInstructionCommute(MachineInstr *MI,
    1201             :                                                       unsigned DstOpIdx,
    1202             :                                                       unsigned BaseOpIdx,
    1203             :                                                       bool BaseOpKilled,
    1204             :                                                       unsigned Dist) {
    1205      254959 :   if (!MI->isCommutable())
    1206             :     return false;
    1207             : 
    1208             :   bool MadeChange = false;
    1209      104200 :   unsigned DstOpReg = MI->getOperand(DstOpIdx).getReg();
    1210      104200 :   unsigned BaseOpReg = MI->getOperand(BaseOpIdx).getReg();
    1211       52100 :   unsigned OpsNum = MI->getDesc().getNumOperands();
    1212      104200 :   unsigned OtherOpIdx = MI->getDesc().getNumDefs();
    1213      278840 :   for (; OtherOpIdx < OpsNum; OtherOpIdx++) {
    1214             :     // The call of findCommutedOpIndices below only checks if BaseOpIdx
    1215             :     // and OtherOpIdx are commutable, it does not really search for
    1216             :     // other commutable operands and does not change the values of passed
    1217             :     // variables.
    1218      244432 :     if (OtherOpIdx == BaseOpIdx || !MI->getOperand(OtherOpIdx).isReg() ||
    1219       60979 :         !TII->findCommutedOpIndices(*MI, BaseOpIdx, OtherOpIdx))
    1220       67828 :       continue;
    1221             : 
    1222       99876 :     unsigned OtherOpReg = MI->getOperand(OtherOpIdx).getReg();
    1223             :     bool AggressiveCommute = false;
    1224             : 
    1225             :     // If OtherOp dies but BaseOp does not, swap the OtherOp and BaseOp
    1226             :     // operands. This makes the live ranges of DstOp and OtherOp joinable.
    1227       49938 :     bool OtherOpKilled = isKilled(*MI, OtherOpReg, MRI, TII, LIS, false);
    1228       49938 :     bool DoCommute = !BaseOpKilled && OtherOpKilled;
    1229             : 
    1230       95479 :     if (!DoCommute &&
    1231       45541 :         isProfitableToCommute(DstOpReg, BaseOpReg, OtherOpReg, MI, Dist)) {
    1232             :       DoCommute = true;
    1233             :       AggressiveCommute = true;
    1234             :     }
    1235             : 
    1236             :     // If it's profitable to commute, try to do so.
    1237       35928 :     if (DoCommute && commuteInstruction(MI, DstOpIdx, BaseOpIdx, OtherOpIdx,
    1238             :                                         Dist)) {
    1239             :       MadeChange = true;
    1240             :       ++NumCommuted;
    1241       18397 :       if (AggressiveCommute) {
    1242             :         ++NumAggrCommuted;
    1243             :         // There might be more than two commutable operands, update BaseOp and
    1244             :         // continue scanning.
    1245             :         BaseOpReg = OtherOpReg;
    1246             :         BaseOpKilled = OtherOpKilled;
    1247       14001 :         continue;
    1248             :       }
    1249             :       // If this was a commute based on kill, we won't do better continuing.
    1250             :       return MadeChange;
    1251             :     }
    1252             :   }
    1253             :   return MadeChange;
    1254             : }
    1255             : 
    1256             : /// For the case where an instruction has a single pair of tied register
    1257             : /// operands, attempt some transformations that may either eliminate the tied
    1258             : /// operands or improve the opportunities for coalescing away the register copy.
    1259             : /// Returns true if no copy needs to be inserted to untie mi's operands
    1260             : /// (either because they were untied, or because mi was rescheduled, and will
    1261             : /// be visited again later). If the shouldOnlyCommute flag is true, only
    1262             : /// instruction commutation is attempted.
    1263      274122 : bool TwoAddressInstructionPass::
    1264             : tryInstructionTransform(MachineBasicBlock::iterator &mi,
    1265             :                         MachineBasicBlock::iterator &nmi,
    1266             :                         unsigned SrcIdx, unsigned DstIdx,
    1267             :                         unsigned Dist, bool shouldOnlyCommute) {
    1268      274122 :   if (OptLevel == CodeGenOpt::None)
    1269             :     return false;
    1270             : 
    1271             :   MachineInstr &MI = *mi;
    1272      509918 :   unsigned regA = MI.getOperand(DstIdx).getReg();
    1273      254959 :   unsigned regB = MI.getOperand(SrcIdx).getReg();
    1274             : 
    1275             :   assert(TargetRegisterInfo::isVirtualRegister(regB) &&
    1276             :          "cannot make instruction into two-address form");
    1277      254959 :   bool regBKilled = isKilled(MI, regB, MRI, TII, LIS, true);
    1278             : 
    1279      254959 :   if (TargetRegisterInfo::isVirtualRegister(regA))
    1280      254929 :     scanUses(regA);
    1281             : 
    1282      254959 :   bool Commuted = tryInstructionCommute(&MI, DstIdx, SrcIdx, regBKilled, Dist);
    1283             : 
    1284             :   // If the instruction is convertible to 3 Addr, instead
    1285             :   // of returning try 3 Addr transformation aggresively and
    1286             :   // use this variable to check later. Because it might be better.
    1287             :   // For example, we can just use `leal (%rsi,%rdi), %eax` and `ret`
    1288             :   // instead of the following code.
    1289             :   //   addl     %esi, %edi
    1290             :   //   movl     %edi, %eax
    1291             :   //   ret
    1292      273342 :   if (Commuted && !MI.isConvertibleTo3Addr())
    1293             :     return false;
    1294             : 
    1295      239568 :   if (shouldOnlyCommute)
    1296             :     return false;
    1297             : 
    1298             :   // If there is one more use of regB later in the same MBB, consider
    1299             :   // re-schedule this MI below it.
    1300      475627 :   if (!Commuted && EnableRescheduling && rescheduleMIBelowKill(mi, nmi, regB)) {
    1301             :     ++NumReSchedDowns;
    1302             :     return true;
    1303             :   }
    1304             : 
    1305             :   // If we commuted, regB may have changed so we should re-sample it to avoid
    1306             :   // confusing the three address conversion below.
    1307      237800 :   if (Commuted) {
    1308        5654 :     regB = MI.getOperand(SrcIdx).getReg();
    1309        2827 :     regBKilled = isKilled(MI, regB, MRI, TII, LIS, true);
    1310             :   }
    1311             : 
    1312      237800 :   if (MI.isConvertibleTo3Addr()) {
    1313             :     // This instruction is potentially convertible to a true
    1314             :     // three-address instruction.  Check if it is profitable.
    1315       30482 :     if (!regBKilled || isProfitableToConv3Addr(regA, regB)) {
    1316             :       // Try to convert it.
    1317        7260 :       if (convertInstTo3Addr(mi, nmi, regA, regB, Dist)) {
    1318             :         ++NumConvertedTo3Addr;
    1319             :         return true; // Done with this instruction.
    1320             :       }
    1321             :     }
    1322             :   }
    1323             : 
    1324             :   // Return if it is commuted but 3 addr conversion is failed.
    1325      231895 :   if (Commuted)
    1326             :     return false;
    1327             : 
    1328             :   // If there is one more use of regB later in the same MBB, consider
    1329             :   // re-schedule it before this MI if it's legal.
    1330      229185 :   if (EnableRescheduling && rescheduleKillAboveMI(mi, nmi, regB)) {
    1331             :     ++NumReSchedUps;
    1332             :     return true;
    1333             :   }
    1334             : 
    1335             :   // If this is an instruction with a load folded into it, try unfolding
    1336             :   // the load, e.g. avoid this:
    1337             :   //   movq %rdx, %rcx
    1338             :   //   addq (%rax), %rcx
    1339             :   // in favor of this:
    1340             :   //   movq (%rax), %rcx
    1341             :   //   addq %rdx, %rcx
    1342             :   // because it's preferable to schedule a load than a register copy.
    1343      228918 :   if (MI.mayLoad() && !regBKilled) {
    1344             :     // Determine if a load can be unfolded.
    1345             :     unsigned LoadRegIndex;
    1346             :     unsigned NewOpc =
    1347        6540 :       TII->getOpcodeAfterMemoryUnfold(MI.getOpcode(),
    1348             :                                       /*UnfoldLoad=*/true,
    1349             :                                       /*UnfoldStore=*/false,
    1350        6540 :                                       &LoadRegIndex);
    1351        3270 :     if (NewOpc != 0) {
    1352        2584 :       const MCInstrDesc &UnfoldMCID = TII->get(NewOpc);
    1353        2584 :       if (UnfoldMCID.getNumDefs() == 1) {
    1354             :         // Unfold the load.
    1355             :         LLVM_DEBUG(dbgs() << "2addr:   UNFOLDING: " << MI);
    1356             :         const TargetRegisterClass *RC =
    1357        5168 :           TRI->getAllocatableClass(
    1358        5168 :             TII->getRegClass(UnfoldMCID, LoadRegIndex, TRI, *MF));
    1359        5168 :         unsigned Reg = MRI->createVirtualRegister(RC);
    1360             :         SmallVector<MachineInstr *, 2> NewMIs;
    1361        5168 :         if (!TII->unfoldMemoryOperand(*MF, MI, Reg,
    1362             :                                       /*UnfoldLoad=*/true,
    1363        2584 :                                       /*UnfoldStore=*/false, NewMIs)) {
    1364             :           LLVM_DEBUG(dbgs() << "2addr: ABANDONING UNFOLD\n");
    1365             :           return false;
    1366             :         }
    1367             :         assert(NewMIs.size() == 2 &&
    1368             :                "Unfolded a load into multiple instructions!");
    1369             :         // The load was previously folded, so this is the only use.
    1370        2584 :         NewMIs[1]->addRegisterKilled(Reg, TRI);
    1371             : 
    1372             :         // Tentatively insert the instructions into the block so that they
    1373             :         // look "normal" to the transformation logic.
    1374        5168 :         MBB->insert(mi, NewMIs[0]);
    1375        5168 :         MBB->insert(mi, NewMIs[1]);
    1376             : 
    1377             :         LLVM_DEBUG(dbgs() << "2addr:    NEW LOAD: " << *NewMIs[0]
    1378             :                           << "2addr:    NEW INST: " << *NewMIs[1]);
    1379             : 
    1380             :         // Transform the instruction, now that it no longer has a load.
    1381        2584 :         unsigned NewDstIdx = NewMIs[1]->findRegisterDefOperandIdx(regA);
    1382        2584 :         unsigned NewSrcIdx = NewMIs[1]->findRegisterUseOperandIdx(regB);
    1383        2584 :         MachineBasicBlock::iterator NewMI = NewMIs[1];
    1384             :         bool TransformResult =
    1385        2584 :           tryInstructionTransform(NewMI, mi, NewSrcIdx, NewDstIdx, Dist, true);
    1386             :         (void)TransformResult;
    1387             :         assert(!TransformResult &&
    1388             :                "tryInstructionTransform() should return false.");
    1389        5168 :         if (NewMIs[1]->getOperand(NewSrcIdx).isKill()) {
    1390             :           // Success, or at least we made an improvement. Keep the unfolded
    1391             :           // instructions and discard the original.
    1392        2410 :           if (LV) {
    1393       19919 :             for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
    1394       17514 :               MachineOperand &MO = MI.getOperand(i);
    1395       29978 :               if (MO.isReg() &&
    1396       12464 :                   TargetRegisterInfo::isVirtualRegister(MO.getReg())) {
    1397        6213 :                 if (MO.isUse()) {
    1398        3808 :                   if (MO.isKill()) {
    1399         400 :                     if (NewMIs[0]->killsRegister(MO.getReg()))
    1400         208 :                       LV->replaceKillInstruction(MO.getReg(), MI, *NewMIs[0]);
    1401             :                     else {
    1402             :                       assert(NewMIs[1]->killsRegister(MO.getReg()) &&
    1403             :                              "Kill missing after load unfold!");
    1404         192 :                       LV->replaceKillInstruction(MO.getReg(), MI, *NewMIs[1]);
    1405             :                     }
    1406             :                   }
    1407        2405 :                 } else if (LV->removeVirtualRegisterDead(MO.getReg(), MI)) {
    1408           0 :                   if (NewMIs[1]->registerDefIsDead(MO.getReg()))
    1409           0 :                     LV->addVirtualRegisterDead(MO.getReg(), *NewMIs[1]);
    1410             :                   else {
    1411             :                     assert(NewMIs[0]->registerDefIsDead(MO.getReg()) &&
    1412             :                            "Dead flag missing after load unfold!");
    1413           0 :                     LV->addVirtualRegisterDead(MO.getReg(), *NewMIs[0]);
    1414             :                   }
    1415             :                 }
    1416             :               }
    1417             :             }
    1418        4810 :             LV->addVirtualRegisterKilled(Reg, *NewMIs[1]);
    1419             :           }
    1420             : 
    1421             :           SmallVector<unsigned, 4> OrigRegs;
    1422        2410 :           if (LIS) {
    1423           0 :             for (const MachineOperand &MO : MI.operands()) {
    1424           0 :               if (MO.isReg())
    1425           0 :                 OrigRegs.push_back(MO.getReg());
    1426             :             }
    1427             :           }
    1428             : 
    1429        2410 :           MI.eraseFromParent();
    1430             : 
    1431             :           // Update LiveIntervals.
    1432        2410 :           if (LIS) {
    1433           0 :             MachineBasicBlock::iterator Begin(NewMIs[0]);
    1434           0 :             MachineBasicBlock::iterator End(NewMIs[1]);
    1435           0 :             LIS->repairIntervalsInRange(MBB, Begin, End, OrigRegs);
    1436             :           }
    1437             : 
    1438        2410 :           mi = NewMIs[1];
    1439             :         } else {
    1440             :           // Transforming didn't eliminate the tie and didn't lead to an
    1441             :           // improvement. Clean up the unfolded instructions and keep the
    1442             :           // original.
    1443             :           LLVM_DEBUG(dbgs() << "2addr: ABANDONING UNFOLD\n");
    1444         174 :           NewMIs[0]->eraseFromParent();
    1445         174 :           NewMIs[1]->eraseFromParent();
    1446             :         }
    1447             :       }
    1448             :     }
    1449             :   }
    1450             : 
    1451             :   return false;
    1452             : }
    1453             : 
    1454             : // Collect tied operands of MI that need to be handled.
    1455             : // Rewrite trivial cases immediately.
    1456             : // Return true if any tied operands where found, including the trivial ones.
    1457     5066832 : bool TwoAddressInstructionPass::
    1458             : collectTiedOperands(MachineInstr *MI, TiedOperandMap &TiedOperands) {
    1459     5066832 :   const MCInstrDesc &MCID = MI->getDesc();
    1460             :   bool AnyOps = false;
    1461     5066832 :   unsigned NumOps = MI->getNumOperands();
    1462             : 
    1463    46480704 :   for (unsigned SrcIdx = 0; SrcIdx < NumOps; ++SrcIdx) {
    1464    20706936 :     unsigned DstIdx = 0;
    1465    20706936 :     if (!MI->isRegTiedToDefOperand(SrcIdx, &DstIdx))
    1466    40841208 :       continue;
    1467             :     AnyOps = true;
    1468      299138 :     MachineOperand &SrcMO = MI->getOperand(SrcIdx);
    1469      299138 :     MachineOperand &DstMO = MI->getOperand(DstIdx);
    1470      299138 :     unsigned SrcReg = SrcMO.getReg();
    1471      299138 :     unsigned DstReg = DstMO.getReg();
    1472             :     // Tied constraint already satisfied?
    1473      299138 :     if (SrcReg == DstReg)
    1474          66 :       continue;
    1475             : 
    1476             :     assert(SrcReg && SrcMO.isUse() && "two address instruction invalid");
    1477             : 
    1478             :     // Deal with undef uses immediately - simply rewrite the src operand.
    1479      324618 :     if (SrcMO.isUndef() && !DstMO.getSubReg()) {
    1480             :       // Constrain the DstReg register class if required.
    1481       25546 :       if (TargetRegisterInfo::isVirtualRegister(DstReg))
    1482       76638 :         if (const TargetRegisterClass *RC = TII->getRegClass(MCID, SrcIdx,
    1483       51092 :                                                              TRI, *MF))
    1484        1460 :           MRI->constrainRegClass(DstReg, RC);
    1485       25546 :       SrcMO.setReg(DstReg);
    1486             :       SrcMO.setSubReg(0);
    1487             :       LLVM_DEBUG(dbgs() << "\t\trewrite undef:\t" << *MI);
    1488       25546 :       continue;
    1489             :     }
    1490      273526 :     TiedOperands[SrcReg].push_back(std::make_pair(SrcIdx, DstIdx));
    1491             :   }
    1492     5066832 :   return AnyOps;
    1493             : }
    1494             : 
    1495             : // Process a list of tied MI operands that all use the same source register.
    1496             : // The tied pairs are of the form (SrcIdx, DstIdx).
    1497             : void
    1498      265826 : TwoAddressInstructionPass::processTiedPairs(MachineInstr *MI,
    1499             :                                             TiedPairList &TiedPairs,
    1500             :                                             unsigned &Dist) {
    1501             :   bool IsEarlyClobber = false;
    1502      531753 :   for (unsigned tpi = 0, tpe = TiedPairs.size(); tpi != tpe; ++tpi) {
    1503      531854 :     const MachineOperand &DstMO = MI->getOperand(TiedPairs[tpi].second);
    1504      265927 :     IsEarlyClobber |= DstMO.isEarlyClobber();
    1505             :   }
    1506             : 
    1507             :   bool RemovedKillFlag = false;
    1508             :   bool AllUsesCopied = true;
    1509             :   unsigned LastCopiedReg = 0;
    1510             :   SlotIndex LastCopyIdx;
    1511             :   unsigned RegB = 0;
    1512             :   unsigned SubRegB = 0;
    1513      797680 :   for (unsigned tpi = 0, tpe = TiedPairs.size(); tpi != tpe; ++tpi) {
    1514      531854 :     unsigned SrcIdx = TiedPairs[tpi].first;
    1515      265927 :     unsigned DstIdx = TiedPairs[tpi].second;
    1516             : 
    1517      265927 :     const MachineOperand &DstMO = MI->getOperand(DstIdx);
    1518      265927 :     unsigned RegA = DstMO.getReg();
    1519             : 
    1520             :     // Grab RegB from the instruction because it may have changed if the
    1521             :     // instruction was commuted.
    1522      265927 :     RegB = MI->getOperand(SrcIdx).getReg();
    1523             :     SubRegB = MI->getOperand(SrcIdx).getSubReg();
    1524             : 
    1525      265927 :     if (RegA == RegB) {
    1526             :       // The register is tied to multiple destinations (or else we would
    1527             :       // not have continued this far), but this use of the register
    1528             :       // already matches the tied destination.  Leave it.
    1529             :       AllUsesCopied = false;
    1530           0 :       continue;
    1531             :     }
    1532             :     LastCopiedReg = RegA;
    1533             : 
    1534             :     assert(TargetRegisterInfo::isVirtualRegister(RegB) &&
    1535             :            "cannot make instruction into two-address form");
    1536             : 
    1537             : #ifndef NDEBUG
    1538             :     // First, verify that we don't have a use of "a" in the instruction
    1539             :     // (a = b + a for example) because our transformation will not
    1540             :     // work. This should never occur because we are in SSA form.
    1541             :     for (unsigned i = 0; i != MI->getNumOperands(); ++i)
    1542             :       assert(i == DstIdx ||
    1543             :              !MI->getOperand(i).isReg() ||
    1544             :              MI->getOperand(i).getReg() != RegA);
    1545             : #endif
    1546             : 
    1547             :     // Emit a copy.
    1548      265927 :     MachineInstrBuilder MIB = BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),
    1549      531854 :                                       TII->get(TargetOpcode::COPY), RegA);
    1550             :     // If this operand is folding a truncation, the truncation now moves to the
    1551             :     // copy so that the register classes remain valid for the operands.
    1552      265927 :     MIB.addReg(RegB, 0, SubRegB);
    1553      265927 :     const TargetRegisterClass *RC = MRI->getRegClass(RegB);
    1554      265927 :     if (SubRegB) {
    1555           2 :       if (TargetRegisterInfo::isVirtualRegister(RegA)) {
    1556             :         assert(TRI->getMatchingSuperRegClass(RC, MRI->getRegClass(RegA),
    1557             :                                              SubRegB) &&
    1558             :                "tied subregister must be a truncation");
    1559             :         // The superreg class will not be used to constrain the subreg class.
    1560             :         RC = nullptr;
    1561             :       }
    1562             :       else {
    1563             :         assert(TRI->getMatchingSuperReg(RegA, SubRegB, MRI->getRegClass(RegB))
    1564             :                && "tied subregister must be a truncation");
    1565             :       }
    1566             :     }
    1567             : 
    1568             :     // Update DistanceMap.
    1569      265927 :     MachineBasicBlock::iterator PrevMI = MI;
    1570             :     --PrevMI;
    1571      797781 :     DistanceMap.insert(std::make_pair(&*PrevMI, Dist));
    1572      531854 :     DistanceMap[MI] = ++Dist;
    1573             : 
    1574      265927 :     if (LIS) {
    1575           0 :       LastCopyIdx = LIS->InsertMachineInstrInMaps(*PrevMI).getRegSlot();
    1576             : 
    1577           0 :       if (TargetRegisterInfo::isVirtualRegister(RegA)) {
    1578           0 :         LiveInterval &LI = LIS->getInterval(RegA);
    1579           0 :         VNInfo *VNI = LI.getNextValue(LastCopyIdx, LIS->getVNInfoAllocator());
    1580             :         SlotIndex endIdx =
    1581           0 :             LIS->getInstructionIndex(*MI).getRegSlot(IsEarlyClobber);
    1582           0 :         LI.addSegment(LiveInterval::Segment(LastCopyIdx, endIdx, VNI));
    1583             :       }
    1584             :     }
    1585             : 
    1586             :     LLVM_DEBUG(dbgs() << "\t\tprepend:\t" << *MIB);
    1587             : 
    1588      265927 :     MachineOperand &MO = MI->getOperand(SrcIdx);
    1589             :     assert(MO.isReg() && MO.getReg() == RegB && MO.isUse() &&
    1590             :            "inconsistent operand info for 2-reg pass");
    1591      265927 :     if (MO.isKill()) {
    1592             :       MO.setIsKill(false);
    1593             :       RemovedKillFlag = true;
    1594             :     }
    1595             : 
    1596             :     // Make sure regA is a legal regclass for the SrcIdx operand.
    1597      797716 :     if (TargetRegisterInfo::isVirtualRegister(RegA) &&
    1598             :         TargetRegisterInfo::isVirtualRegister(RegB))
    1599      265862 :       MRI->constrainRegClass(RegA, RC);
    1600      265927 :     MO.setReg(RegA);
    1601             :     // The getMatchingSuper asserts guarantee that the register class projected
    1602             :     // by SubRegB is compatible with RegA with no subregister. So regardless of
    1603             :     // whether the dest oper writes a subreg, the source oper should not.
    1604             :     MO.setSubReg(0);
    1605             : 
    1606             :     // Propagate SrcRegMap.
    1607      531854 :     SrcRegMap[RegA] = RegB;
    1608             :   }
    1609             : 
    1610      265826 :   if (AllUsesCopied) {
    1611      265826 :     if (!IsEarlyClobber) {
    1612             :       // Replace other (un-tied) uses of regB with LastCopiedReg.
    1613     2586578 :       for (MachineOperand &MO : MI->operands()) {
    1614     1034277 :         if (MO.isReg() && MO.getReg() == RegB &&
    1615             :             MO.isUse()) {
    1616        4278 :           if (MO.isKill()) {
    1617             :             MO.setIsKill(false);
    1618             :             RemovedKillFlag = true;
    1619             :           }
    1620        4278 :           MO.setReg(LastCopiedReg);
    1621             :           MO.setSubReg(MO.getSubReg());
    1622             :         }
    1623             :       }
    1624             :     }
    1625             : 
    1626             :     // Update live variables for regB.
    1627      265826 :     if (RemovedKillFlag && LV && LV->getVarInfo(RegB).removeKill(*MI)) {
    1628      225534 :       MachineBasicBlock::iterator PrevMI = MI;
    1629             :       --PrevMI;
    1630      451068 :       LV->addVirtualRegisterKilled(RegB, *PrevMI);
    1631             :     }
    1632             : 
    1633             :     // Update LiveIntervals.
    1634      265826 :     if (LIS) {
    1635           0 :       LiveInterval &LI = LIS->getInterval(RegB);
    1636           0 :       SlotIndex MIIdx = LIS->getInstructionIndex(*MI);
    1637           0 :       LiveInterval::const_iterator I = LI.find(MIIdx);
    1638             :       assert(I != LI.end() && "RegB must be live-in to use.");
    1639             : 
    1640             :       SlotIndex UseIdx = MIIdx.getRegSlot(IsEarlyClobber);
    1641           0 :       if (I->end == UseIdx)
    1642           0 :         LI.removeSegment(LastCopyIdx, UseIdx);
    1643             :     }
    1644           0 :   } else if (RemovedKillFlag) {
    1645             :     // Some tied uses of regB matched their destination registers, so
    1646             :     // regB is still used in this instruction, but a kill flag was
    1647             :     // removed from a different tied use of regB, so now we need to add
    1648             :     // a kill flag to one of the remaining uses of regB.
    1649           0 :     for (MachineOperand &MO : MI->operands()) {
    1650           0 :       if (MO.isReg() && MO.getReg() == RegB && MO.isUse()) {
    1651             :         MO.setIsKill(true);
    1652             :         break;
    1653             :       }
    1654             :     }
    1655             :   }
    1656      265826 : }
    1657             : 
    1658             : /// Reduce two-address instructions to two operands.
    1659      227123 : bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &Func) {
    1660      227123 :   MF = &Func;
    1661      227123 :   const TargetMachine &TM = MF->getTarget();
    1662      227123 :   MRI = &MF->getRegInfo();
    1663      227123 :   TII = MF->getSubtarget().getInstrInfo();
    1664      227123 :   TRI = MF->getSubtarget().getRegisterInfo();
    1665      227123 :   InstrItins = MF->getSubtarget().getInstrItineraryData();
    1666      227123 :   LV = getAnalysisIfAvailable<LiveVariables>();
    1667      227123 :   LIS = getAnalysisIfAvailable<LiveIntervals>();
    1668      227123 :   if (auto *AAPass = getAnalysisIfAvailable<AAResultsWrapperPass>())
    1669      182330 :     AA = &AAPass->getAAResults();
    1670             :   else
    1671       44793 :     AA = nullptr;
    1672      227123 :   OptLevel = TM.getOptLevel();
    1673             :   // Disable optimizations if requested. We cannot skip the whole pass as some
    1674             :   // fixups are necessary for correctness.
    1675      227123 :   if (skipFunction(Func.getFunction()))
    1676       37765 :     OptLevel = CodeGenOpt::None;
    1677             : 
    1678             :   bool MadeChange = false;
    1679             : 
    1680             :   LLVM_DEBUG(dbgs() << "********** REWRITING TWO-ADDR INSTRS **********\n");
    1681             :   LLVM_DEBUG(dbgs() << "********** Function: " << MF->getName() << '\n');
    1682             : 
    1683             :   // This pass takes the function out of SSA form.
    1684      227123 :   MRI->leaveSSA();
    1685             : 
    1686      227122 :   TiedOperandMap TiedOperands;
    1687      227123 :   for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end();
    1688      669746 :        MBBI != MBBE; ++MBBI) {
    1689      442624 :     MBB = &*MBBI;
    1690      442624 :     unsigned Dist = 0;
    1691      442624 :     DistanceMap.clear();
    1692      442624 :     SrcRegMap.clear();
    1693      442624 :     DstRegMap.clear();
    1694      442624 :     Processed.clear();
    1695      442624 :     SunkInstrs.clear();
    1696      885248 :     for (MachineBasicBlock::iterator mi = MBB->begin(), me = MBB->end();
    1697     5545272 :          mi != me; ) {
    1698     5102649 :       MachineBasicBlock::iterator nmi = std::next(mi);
    1699             :       // Don't revisit an instruction previously converted by target. It may
    1700             :       // contain undef register operands (%noreg), which are not handled.
    1701     5103079 :       if (mi->isDebugInstr() || SunkInstrs.count(&*mi)) {
    1702       35816 :         mi = nmi;
    1703     4848144 :         continue;
    1704             :       }
    1705             : 
    1706             :       // Expand REG_SEQUENCE instructions. This will position mi at the first
    1707             :       // expanded instruction.
    1708     5066833 :       if (mi->isRegSequence())
    1709       45614 :         eliminateRegSequence(mi);
    1710             : 
    1711    15200499 :       DistanceMap.insert(std::make_pair(&*mi, ++Dist));
    1712             : 
    1713     5066833 :       processCopy(&*mi);
    1714             : 
    1715             :       // First scan through all the tied register uses in this instruction
    1716             :       // and record a list of pairs of tied operands for each register.
    1717     9835745 :       if (!collectTiedOperands(&*mi, TiedOperands)) {
    1718     4768913 :         mi = nmi;
    1719     4768913 :         continue;
    1720             :       }
    1721             : 
    1722             :       ++NumTwoAddressInstrs;
    1723             :       MadeChange = true;
    1724             :       LLVM_DEBUG(dbgs() << '\t' << *mi);
    1725             : 
    1726             :       // If the instruction has a single pair of tied operands, try some
    1727             :       // transformations that may either eliminate the tied operands or
    1728             :       // improve the opportunities for coalescing away the register copy.
    1729      297919 :       if (TiedOperands.size() == 1) {
    1730             :         SmallVectorImpl<std::pair<unsigned, unsigned>> &TiedPairs
    1731      271557 :           = TiedOperands.begin()->second;
    1732      271557 :         if (TiedPairs.size() == 1) {
    1733      271538 :           unsigned SrcIdx = TiedPairs[0].first;
    1734      271538 :           unsigned DstIdx = TiedPairs[0].second;
    1735      543076 :           unsigned SrcReg = mi->getOperand(SrcIdx).getReg();
    1736      271538 :           unsigned DstReg = mi->getOperand(DstIdx).getReg();
    1737      550675 :           if (SrcReg != DstReg &&
    1738      271538 :               tryInstructionTransform(mi, nmi, SrcIdx, DstIdx, Dist, false)) {
    1739             :             // The tied operands have been eliminated or shifted further down
    1740             :             // the block to ease elimination. Continue processing with 'nmi'.
    1741        7599 :             TiedOperands.clear();
    1742        7599 :             mi = nmi;
    1743        7599 :             continue;
    1744             :           }
    1745             :         }
    1746             :       }
    1747             : 
    1748             :       // Now iterate over the information collected above.
    1749      846466 :       for (auto &TO : TiedOperands) {
    1750      531652 :         processTiedPairs(&*mi, TO.second, Dist);
    1751             :         LLVM_DEBUG(dbgs() << "\t\trewrite to:\t" << *mi);
    1752             :       }
    1753             : 
    1754             :       // Rewrite INSERT_SUBREG as COPY now that we no longer need SSA form.
    1755      290320 :       if (mi->isInsertSubreg()) {
    1756             :         // From %reg = INSERT_SUBREG %reg, %subreg, subidx
    1757             :         // To   %reg:subidx = COPY %subreg
    1758       48276 :         unsigned SubIdx = mi->getOperand(3).getImm();
    1759       48276 :         mi->RemoveOperand(3);
    1760             :         assert(mi->getOperand(0).getSubReg() == 0 && "Unexpected subreg idx");
    1761       48276 :         mi->getOperand(0).setSubReg(SubIdx);
    1762       48276 :         mi->getOperand(0).setIsUndef(mi->getOperand(1).isUndef());
    1763       48276 :         mi->RemoveOperand(1);
    1764       48276 :         mi->setDesc(TII->get(TargetOpcode::COPY));
    1765             :         LLVM_DEBUG(dbgs() << "\t\tconvert to:\t" << *mi);
    1766             :       }
    1767             : 
    1768             :       // Clear TiedOperands here instead of at the top of the loop
    1769             :       // since most instructions do not have tied operands.
    1770      290320 :       TiedOperands.clear();
    1771      290320 :       mi = nmi;
    1772             :     }
    1773             :   }
    1774             : 
    1775      227122 :   if (LIS)
    1776           0 :     MF->verify(this, "After two-address instruction pass");
    1777             : 
    1778      227122 :   return MadeChange;
    1779             : }
    1780             : 
    1781             : /// Eliminate a REG_SEQUENCE instruction as part of the de-ssa process.
    1782             : ///
    1783             : /// The instruction is turned into a sequence of sub-register copies:
    1784             : ///
    1785             : ///   %dst = REG_SEQUENCE %v1, ssub0, %v2, ssub1
    1786             : ///
    1787             : /// Becomes:
    1788             : ///
    1789             : ///   undef %dst:ssub0 = COPY %v1
    1790             : ///   %dst:ssub1 = COPY %v2
    1791       45614 : void TwoAddressInstructionPass::
    1792             : eliminateRegSequence(MachineBasicBlock::iterator &MBBI) {
    1793             :   MachineInstr &MI = *MBBI;
    1794       45614 :   unsigned DstReg = MI.getOperand(0).getReg();
    1795       45614 :   if (MI.getOperand(0).getSubReg() ||
    1796       91228 :       TargetRegisterInfo::isPhysicalRegister(DstReg) ||
    1797       45614 :       !(MI.getNumOperands() & 1)) {
    1798             :     LLVM_DEBUG(dbgs() << "Illegal REG_SEQUENCE instruction:" << MI);
    1799           0 :     llvm_unreachable(nullptr);
    1800             :   }
    1801             : 
    1802             :   SmallVector<unsigned, 4> OrigRegs;
    1803       45614 :   if (LIS) {
    1804           0 :     OrigRegs.push_back(MI.getOperand(0).getReg());
    1805           0 :     for (unsigned i = 1, e = MI.getNumOperands(); i < e; i += 2)
    1806           0 :       OrigRegs.push_back(MI.getOperand(i).getReg());
    1807             :   }
    1808             : 
    1809             :   bool DefEmitted = false;
    1810      182928 :   for (unsigned i = 1, e = MI.getNumOperands(); i < e; i += 2) {
    1811      137314 :     MachineOperand &UseMO = MI.getOperand(i);
    1812      137314 :     unsigned SrcReg = UseMO.getReg();
    1813      274628 :     unsigned SubIdx = MI.getOperand(i+1).getImm();
    1814             :     // Nothing needs to be inserted for undef operands.
    1815      137314 :     if (UseMO.isUndef())
    1816        4243 :       continue;
    1817             : 
    1818             :     // Defer any kill flag to the last operand using SrcReg. Otherwise, we
    1819             :     // might insert a COPY that uses SrcReg after is was killed.
    1820             :     bool isKill = UseMO.isKill();
    1821      133071 :     if (isKill)
    1822      258403 :       for (unsigned j = i + 2; j < e; j += 2)
    1823      147669 :         if (MI.getOperand(j).getReg() == SrcReg) {
    1824             :           MI.getOperand(j).setIsKill();
    1825             :           UseMO.setIsKill(false);
    1826             :           isKill = false;
    1827        7199 :           break;
    1828             :         }
    1829             : 
    1830             :     // Insert the sub-register copy.
    1831      266142 :     MachineInstr *CopyMI = BuildMI(*MI.getParent(), MI, MI.getDebugLoc(),
    1832      133071 :                                    TII->get(TargetOpcode::COPY))
    1833      133071 :                                .addReg(DstReg, RegState::Define, SubIdx)
    1834      133071 :                                .add(UseMO);
    1835             : 
    1836             :     // The first def needs an undef flag because there is no live register
    1837             :     // before it.
    1838      133071 :     if (!DefEmitted) {
    1839       45614 :       CopyMI->getOperand(0).setIsUndef(true);
    1840             :       // Return an iterator pointing to the first inserted instr.
    1841       45614 :       MBBI = CopyMI;
    1842             :     }
    1843             :     DefEmitted = true;
    1844             : 
    1845             :     // Update LiveVariables' kill info.
    1846      243738 :     if (LV && isKill && !TargetRegisterInfo::isPhysicalRegister(SrcReg))
    1847      110667 :       LV->replaceKillInstruction(SrcReg, MI, *CopyMI);
    1848             : 
    1849             :     LLVM_DEBUG(dbgs() << "Inserted: " << *CopyMI);
    1850             :   }
    1851             : 
    1852             :   MachineBasicBlock::iterator EndMBBI =
    1853       45614 :       std::next(MachineBasicBlock::iterator(MI));
    1854             : 
    1855       45614 :   if (!DefEmitted) {
    1856             :     LLVM_DEBUG(dbgs() << "Turned: " << MI << " into an IMPLICIT_DEF");
    1857           0 :     MI.setDesc(TII->get(TargetOpcode::IMPLICIT_DEF));
    1858           0 :     for (int j = MI.getNumOperands() - 1, ee = 0; j > ee; --j)
    1859           0 :       MI.RemoveOperand(j);
    1860             :   } else {
    1861             :     LLVM_DEBUG(dbgs() << "Eliminated: " << MI);
    1862       45614 :     MI.eraseFromParent();
    1863             :   }
    1864             : 
    1865             :   // Udpate LiveIntervals.
    1866       45614 :   if (LIS)
    1867           0 :     LIS->repairIntervalsInRange(MBB, MBBI, EndMBBI, OrigRegs);
    1868      349121 : }

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