lib/CodeGen/MachineInstrBundle.cpp - llvm - Git at Google

 //===-- lib/CodeGen/MachineInstrBundle.cpp --------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/CodeGen/MachineInstrBundle.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
 #include "llvm/CodeGen/TargetRegisterInfo.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include <utility>
 using namespace llvm;

 namespace {
   class UnpackMachineBundles : public MachineFunctionPass {
   public:
     static char ID; // Pass identification
     UnpackMachineBundles(
         std::function<bool(const MachineFunction &)> Ftor = nullptr)
         : MachineFunctionPass(ID), PredicateFtor(std::move(Ftor)) {
       initializeUnpackMachineBundlesPass(*PassRegistry::getPassRegistry());
     }

     bool runOnMachineFunction(MachineFunction &MF) override;

   private:
     std::function<bool(const MachineFunction &)> PredicateFtor;
   };
 } // end anonymous namespace

 char UnpackMachineBundles::ID = 0;
 char &llvm::UnpackMachineBundlesID = UnpackMachineBundles::ID;
 INITIALIZE_PASS(UnpackMachineBundles, "unpack-mi-bundles",
                 "Unpack machine instruction bundles", false, false)

 bool UnpackMachineBundles::runOnMachineFunction(MachineFunction &MF) {
   if (PredicateFtor && !PredicateFtor(MF))
     return false;

   bool Changed = false;
   for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
     MachineBasicBlock *MBB = &*I;

     for (MachineBasicBlock::instr_iterator MII = MBB->instr_begin(),
            MIE = MBB->instr_end(); MII != MIE; ) {
       MachineInstr *MI = &*MII;

       // Remove BUNDLE instruction and the InsideBundle flags from bundled
       // instructions.
       if (MI->isBundle()) {
         while (++MII != MIE && MII->isBundledWithPred()) {
           MII->unbundleFromPred();
           for (unsigned i = 0, e = MII->getNumOperands(); i != e; ++i) {
             MachineOperand &MO = MII->getOperand(i);
             if (MO.isReg() && MO.isInternalRead())
               MO.setIsInternalRead(false);
           }
         }
         MI->eraseFromParent();

         Changed = true;
         continue;
       }

       ++MII;
     }
   }

   return Changed;
 }

 FunctionPass *
 llvm::createUnpackMachineBundles(
     std::function<bool(const MachineFunction &)> Ftor) {
   return new UnpackMachineBundles(std::move(Ftor));
 }

 namespace {
   class FinalizeMachineBundles : public MachineFunctionPass {
   public:
     static char ID; // Pass identification
     FinalizeMachineBundles() : MachineFunctionPass(ID) {
       initializeFinalizeMachineBundlesPass(*PassRegistry::getPassRegistry());
     }

     bool runOnMachineFunction(MachineFunction &MF) override;
   };
 } // end anonymous namespace

 char FinalizeMachineBundles::ID = 0;
 char &llvm::FinalizeMachineBundlesID = FinalizeMachineBundles::ID;
 INITIALIZE_PASS(FinalizeMachineBundles, "finalize-mi-bundles",
                 "Finalize machine instruction bundles", false, false)

 bool FinalizeMachineBundles::runOnMachineFunction(MachineFunction &MF) {
   return llvm::finalizeBundles(MF);
 }

 /// Return the first found DebugLoc that has a DILocation, given a range of
 /// instructions. The search range is from FirstMI to LastMI (exclusive). If no
 /// DILocation is found, then an empty location is returned.
 static DebugLoc getDebugLoc(MachineBasicBlock::instr_iterator FirstMI,
                             MachineBasicBlock::instr_iterator LastMI) {
   for (auto MII = FirstMI; MII != LastMI; ++MII)
     if (MII->getDebugLoc().get())
       return MII->getDebugLoc();
   return DebugLoc();
 }

 /// finalizeBundle - Finalize a machine instruction bundle which includes
 /// a sequence of instructions starting from FirstMI to LastMI (exclusive).
 /// This routine adds a BUNDLE instruction to represent the bundle, it adds
 /// IsInternalRead markers to MachineOperands which are defined inside the
 /// bundle, and it copies externally visible defs and uses to the BUNDLE
 /// instruction.
 void llvm::finalizeBundle(MachineBasicBlock &MBB,
                           MachineBasicBlock::instr_iterator FirstMI,
                           MachineBasicBlock::instr_iterator LastMI) {
   assert(FirstMI != LastMI && "Empty bundle?");
   MIBundleBuilder Bundle(MBB, FirstMI, LastMI);

   MachineFunction &MF = *MBB.getParent();
   const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
   const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();

   MachineInstrBuilder MIB =
       BuildMI(MF, getDebugLoc(FirstMI, LastMI), TII->get(TargetOpcode::BUNDLE));
   Bundle.prepend(MIB);

   SmallVector<unsigned, 32> LocalDefs;
   SmallSet<unsigned, 32> LocalDefSet;
   SmallSet<unsigned, 8> DeadDefSet;
   SmallSet<unsigned, 16> KilledDefSet;
   SmallVector<unsigned, 8> ExternUses;
   SmallSet<unsigned, 8> ExternUseSet;
   SmallSet<unsigned, 8> KilledUseSet;
   SmallSet<unsigned, 8> UndefUseSet;
   SmallVector<MachineOperand*, 4> Defs;
   for (auto MII = FirstMI; MII != LastMI; ++MII) {
     for (unsigned i = 0, e = MII->getNumOperands(); i != e; ++i) {
       MachineOperand &MO = MII->getOperand(i);
       if (!MO.isReg())
         continue;
       if (MO.isDef()) {
         Defs.push_back(&MO);
         continue;
       }

       unsigned Reg = MO.getReg();
       if (!Reg)
         continue;
       assert(TargetRegisterInfo::isPhysicalRegister(Reg));
       if (LocalDefSet.count(Reg)) {
         MO.setIsInternalRead();
         if (MO.isKill())
           // Internal def is now killed.
           KilledDefSet.insert(Reg);
       } else {
         if (ExternUseSet.insert(Reg).second) {
           ExternUses.push_back(Reg);
           if (MO.isUndef())
             UndefUseSet.insert(Reg);
         }
         if (MO.isKill())
           // External def is now killed.
           KilledUseSet.insert(Reg);
       }
     }

     for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
       MachineOperand &MO = *Defs[i];
       unsigned Reg = MO.getReg();
       if (!Reg)
         continue;

       if (LocalDefSet.insert(Reg).second) {
         LocalDefs.push_back(Reg);
         if (MO.isDead()) {
           DeadDefSet.insert(Reg);
         }
       } else {
         // Re-defined inside the bundle, it's no longer killed.
         KilledDefSet.erase(Reg);
         if (!MO.isDead())
           // Previously defined but dead.
           DeadDefSet.erase(Reg);
       }

       if (!MO.isDead()) {
         for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
           unsigned SubReg = *SubRegs;
           if (LocalDefSet.insert(SubReg).second)
             LocalDefs.push_back(SubReg);
         }
       }
     }

     Defs.clear();
   }

   SmallSet<unsigned, 32> Added;
   for (unsigned i = 0, e = LocalDefs.size(); i != e; ++i) {
     unsigned Reg = LocalDefs[i];
     if (Added.insert(Reg).second) {
       // If it's not live beyond end of the bundle, mark it dead.
       bool isDead = DeadDefSet.count(Reg) || KilledDefSet.count(Reg);
       MIB.addReg(Reg, getDefRegState(true) | getDeadRegState(isDead) |
                  getImplRegState(true));
     }
   }

   for (unsigned i = 0, e = ExternUses.size(); i != e; ++i) {
     unsigned Reg = ExternUses[i];
     bool isKill = KilledUseSet.count(Reg);
     bool isUndef = UndefUseSet.count(Reg);
     MIB.addReg(Reg, getKillRegState(isKill) | getUndefRegState(isUndef) |
                getImplRegState(true));
   }

   // Set FrameSetup/FrameDestroy for the bundle. If any of the instructions got
   // the property, then also set it on the bundle.
   for (auto MII = FirstMI; MII != LastMI; ++MII) {
     if (MII->getFlag(MachineInstr::FrameSetup))
       MIB.setMIFlag(MachineInstr::FrameSetup);
     if (MII->getFlag(MachineInstr::FrameDestroy))
       MIB.setMIFlag(MachineInstr::FrameDestroy);
   }
 }

 /// finalizeBundle - Same functionality as the previous finalizeBundle except
 /// the last instruction in the bundle is not provided as an input. This is
 /// used in cases where bundles are pre-determined by marking instructions
 /// with 'InsideBundle' marker. It returns the MBB instruction iterator that
 /// points to the end of the bundle.
 MachineBasicBlock::instr_iterator
 llvm::finalizeBundle(MachineBasicBlock &MBB,
                      MachineBasicBlock::instr_iterator FirstMI) {
   MachineBasicBlock::instr_iterator E = MBB.instr_end();
   MachineBasicBlock::instr_iterator LastMI = std::next(FirstMI);
   while (LastMI != E && LastMI->isInsideBundle())
     ++LastMI;
   finalizeBundle(MBB, FirstMI, LastMI);
   return LastMI;
 }

 /// finalizeBundles - Finalize instruction bundles in the specified
 /// MachineFunction. Return true if any bundles are finalized.
 bool llvm::finalizeBundles(MachineFunction &MF) {
   bool Changed = false;
   for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
     MachineBasicBlock &MBB = *I;
     MachineBasicBlock::instr_iterator MII = MBB.instr_begin();
     MachineBasicBlock::instr_iterator MIE = MBB.instr_end();
     if (MII == MIE)
       continue;
     assert(!MII->isInsideBundle() &&
            "First instr cannot be inside bundle before finalization!");

     for (++MII; MII != MIE; ) {
       if (!MII->isInsideBundle())
         ++MII;
       else {
         MII = finalizeBundle(MBB, std::prev(MII));
         Changed = true;
       }
     }
   }

   return Changed;
 }

 //===----------------------------------------------------------------------===//
 // MachineOperand iterator
 //===----------------------------------------------------------------------===//

 MachineOperandIteratorBase::VirtRegInfo
 MachineOperandIteratorBase::analyzeVirtReg(unsigned Reg,
                     SmallVectorImpl<std::pair<MachineInstr*, unsigned> > *Ops) {
   VirtRegInfo RI = { false, false, false };
   for(; isValid(); ++*this) {
     MachineOperand &MO = deref();
     if (!MO.isReg() || MO.getReg() != Reg)
       continue;

     // Remember each (MI, OpNo) that refers to Reg.
     if (Ops)
       Ops->push_back(std::make_pair(MO.getParent(), getOperandNo()));

     // Both defs and uses can read virtual registers.
     if (MO.readsReg()) {
       RI.Reads = true;
       if (MO.isDef())
         RI.Tied = true;
     }

     // Only defs can write.
     if (MO.isDef())
       RI.Writes = true;
     else if (!RI.Tied && MO.getParent()->isRegTiedToDefOperand(getOperandNo()))
       RI.Tied = true;
   }
   return RI;
 }

 MachineOperandIteratorBase::PhysRegInfo
 MachineOperandIteratorBase::analyzePhysReg(unsigned Reg,
                                            const TargetRegisterInfo *TRI) {
   bool AllDefsDead = true;
   PhysRegInfo PRI = {false, false, false, false, false, false, false, false};

   assert(TargetRegisterInfo::isPhysicalRegister(Reg) &&
          "analyzePhysReg not given a physical register!");
   for (; isValid(); ++*this) {
     MachineOperand &MO = deref();

     if (MO.isRegMask() && MO.clobbersPhysReg(Reg)) {
       PRI.Clobbered = true;
       continue;
     }

     if (!MO.isReg())
       continue;

     unsigned MOReg = MO.getReg();
     if (!MOReg || !TargetRegisterInfo::isPhysicalRegister(MOReg))
       continue;

     if (!TRI->regsOverlap(MOReg, Reg))
       continue;

     bool Covered = TRI->isSuperRegisterEq(Reg, MOReg);
     if (MO.readsReg()) {
       PRI.Read = true;
       if (Covered) {
         PRI.FullyRead = true;
         if (MO.isKill())
           PRI.Killed = true;
       }
     } else if (MO.isDef()) {
       PRI.Defined = true;
       if (Covered)
         PRI.FullyDefined = true;
       if (!MO.isDead())
         AllDefsDead = false;
     }
   }

   if (AllDefsDead) {
     if (PRI.FullyDefined || PRI.Clobbered)
       PRI.DeadDef = true;
     else if (PRI.Defined)
       PRI.PartialDeadDef = true;
   }

   return PRI;
 }
	//===-- lib/CodeGen/MachineInstrBundle.cpp --------------------------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/CodeGen/MachineInstrBundle.h"
	#include "llvm/ADT/SmallSet.h"
	#include "llvm/ADT/SmallVector.h"
	#include "llvm/CodeGen/MachineFunctionPass.h"
	#include "llvm/CodeGen/MachineInstrBuilder.h"
	#include "llvm/CodeGen/Passes.h"
	#include "llvm/CodeGen/TargetInstrInfo.h"
	#include "llvm/CodeGen/TargetRegisterInfo.h"
	#include "llvm/CodeGen/TargetSubtargetInfo.h"
	#include "llvm/Target/TargetMachine.h"
	#include <utility>
	using namespace llvm;

	namespace {
	class UnpackMachineBundles : public MachineFunctionPass {
	public:
	static char ID; // Pass identification
	UnpackMachineBundles(
	std::function<bool(const MachineFunction &)> Ftor = nullptr)
	: MachineFunctionPass(ID), PredicateFtor(std::move(Ftor)) {
	initializeUnpackMachineBundlesPass(*PassRegistry::getPassRegistry());
	}

	bool runOnMachineFunction(MachineFunction &MF) override;

	private:
	std::function<bool(const MachineFunction &)> PredicateFtor;
	};
	} // end anonymous namespace

	char UnpackMachineBundles::ID = 0;
	char &llvm::UnpackMachineBundlesID = UnpackMachineBundles::ID;
	INITIALIZE_PASS(UnpackMachineBundles, "unpack-mi-bundles",
	"Unpack machine instruction bundles", false, false)

	bool UnpackMachineBundles::runOnMachineFunction(MachineFunction &MF) {
	if (PredicateFtor && !PredicateFtor(MF))
	return false;

	bool Changed = false;
	for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
	MachineBasicBlock MBB = &I;

	for (MachineBasicBlock::instr_iterator MII = MBB->instr_begin(),
	MIE = MBB->instr_end(); MII != MIE; ) {
	MachineInstr MI = &MII;

	// Remove BUNDLE instruction and the InsideBundle flags from bundled
	// instructions.
	if (MI->isBundle()) {
	while (++MII != MIE && MII->isBundledWithPred()) {
	MII->unbundleFromPred();
	for (unsigned i = 0, e = MII->getNumOperands(); i != e; ++i) {
	MachineOperand &MO = MII->getOperand(i);
	if (MO.isReg() && MO.isInternalRead())
	MO.setIsInternalRead(false);
	}
	}
	MI->eraseFromParent();

	Changed = true;
	continue;
	}

	++MII;
	}
	}

	return Changed;
	}

	FunctionPass *
	llvm::createUnpackMachineBundles(
	std::function<bool(const MachineFunction &)> Ftor) {
	return new UnpackMachineBundles(std::move(Ftor));
	}

	namespace {
	class FinalizeMachineBundles : public MachineFunctionPass {
	public:
	static char ID; // Pass identification
	FinalizeMachineBundles() : MachineFunctionPass(ID) {
	initializeFinalizeMachineBundlesPass(*PassRegistry::getPassRegistry());
	}

	bool runOnMachineFunction(MachineFunction &MF) override;
	};
	} // end anonymous namespace

	char FinalizeMachineBundles::ID = 0;
	char &llvm::FinalizeMachineBundlesID = FinalizeMachineBundles::ID;
	INITIALIZE_PASS(FinalizeMachineBundles, "finalize-mi-bundles",
	"Finalize machine instruction bundles", false, false)

	bool FinalizeMachineBundles::runOnMachineFunction(MachineFunction &MF) {
	return llvm::finalizeBundles(MF);
	}

	/// Return the first found DebugLoc that has a DILocation, given a range of
	/// instructions. The search range is from FirstMI to LastMI (exclusive). If no
	/// DILocation is found, then an empty location is returned.
	static DebugLoc getDebugLoc(MachineBasicBlock::instr_iterator FirstMI,
	MachineBasicBlock::instr_iterator LastMI) {
	for (auto MII = FirstMI; MII != LastMI; ++MII)
	if (MII->getDebugLoc().get())
	return MII->getDebugLoc();
	return DebugLoc();
	}

	/// finalizeBundle - Finalize a machine instruction bundle which includes
	/// a sequence of instructions starting from FirstMI to LastMI (exclusive).
	/// This routine adds a BUNDLE instruction to represent the bundle, it adds
	/// IsInternalRead markers to MachineOperands which are defined inside the
	/// bundle, and it copies externally visible defs and uses to the BUNDLE
	/// instruction.
	void llvm::finalizeBundle(MachineBasicBlock &MBB,
	MachineBasicBlock::instr_iterator FirstMI,
	MachineBasicBlock::instr_iterator LastMI) {
	assert(FirstMI != LastMI && "Empty bundle?");
	MIBundleBuilder Bundle(MBB, FirstMI, LastMI);

	MachineFunction &MF = *MBB.getParent();
	const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
	const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();

	MachineInstrBuilder MIB =
	BuildMI(MF, getDebugLoc(FirstMI, LastMI), TII->get(TargetOpcode::BUNDLE));
	Bundle.prepend(MIB);

	SmallVector<unsigned, 32> LocalDefs;
	SmallSet<unsigned, 32> LocalDefSet;
	SmallSet<unsigned, 8> DeadDefSet;
	SmallSet<unsigned, 16> KilledDefSet;
	SmallVector<unsigned, 8> ExternUses;
	SmallSet<unsigned, 8> ExternUseSet;
	SmallSet<unsigned, 8> KilledUseSet;
	SmallSet<unsigned, 8> UndefUseSet;
	SmallVector<MachineOperand*, 4> Defs;
	for (auto MII = FirstMI; MII != LastMI; ++MII) {
	for (unsigned i = 0, e = MII->getNumOperands(); i != e; ++i) {
	MachineOperand &MO = MII->getOperand(i);
	if (!MO.isReg())
	continue;
	if (MO.isDef()) {
	Defs.push_back(&MO);
	continue;
	}

	unsigned Reg = MO.getReg();
	if (!Reg)
	continue;
	assert(TargetRegisterInfo::isPhysicalRegister(Reg));
	if (LocalDefSet.count(Reg)) {
	MO.setIsInternalRead();
	if (MO.isKill())
	// Internal def is now killed.
	KilledDefSet.insert(Reg);
	} else {
	if (ExternUseSet.insert(Reg).second) {
	ExternUses.push_back(Reg);
	if (MO.isUndef())
	UndefUseSet.insert(Reg);
	}
	if (MO.isKill())
	// External def is now killed.
	KilledUseSet.insert(Reg);
	}
	}

	for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
	MachineOperand &MO = *Defs[i];
	unsigned Reg = MO.getReg();
	if (!Reg)
	continue;

	if (LocalDefSet.insert(Reg).second) {
	LocalDefs.push_back(Reg);
	if (MO.isDead()) {
	DeadDefSet.insert(Reg);
	}
	} else {
	// Re-defined inside the bundle, it's no longer killed.
	KilledDefSet.erase(Reg);
	if (!MO.isDead())
	// Previously defined but dead.
	DeadDefSet.erase(Reg);
	}

	if (!MO.isDead()) {
	for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
	unsigned SubReg = *SubRegs;
	if (LocalDefSet.insert(SubReg).second)
	LocalDefs.push_back(SubReg);
	}
	}
	}

	Defs.clear();
	}

	SmallSet<unsigned, 32> Added;
	for (unsigned i = 0, e = LocalDefs.size(); i != e; ++i) {
	unsigned Reg = LocalDefs[i];
	if (Added.insert(Reg).second) {
	// If it's not live beyond end of the bundle, mark it dead.
	bool isDead = DeadDefSet.count(Reg) \|\| KilledDefSet.count(Reg);
	MIB.addReg(Reg, getDefRegState(true) \| getDeadRegState(isDead) \|
	getImplRegState(true));
	}
	}

	for (unsigned i = 0, e = ExternUses.size(); i != e; ++i) {
	unsigned Reg = ExternUses[i];
	bool isKill = KilledUseSet.count(Reg);
	bool isUndef = UndefUseSet.count(Reg);
	MIB.addReg(Reg, getKillRegState(isKill) \| getUndefRegState(isUndef) \|
	getImplRegState(true));
	}

	// Set FrameSetup/FrameDestroy for the bundle. If any of the instructions got
	// the property, then also set it on the bundle.
	for (auto MII = FirstMI; MII != LastMI; ++MII) {
	if (MII->getFlag(MachineInstr::FrameSetup))
	MIB.setMIFlag(MachineInstr::FrameSetup);
	if (MII->getFlag(MachineInstr::FrameDestroy))
	MIB.setMIFlag(MachineInstr::FrameDestroy);
	}
	}

	/// finalizeBundle - Same functionality as the previous finalizeBundle except
	/// the last instruction in the bundle is not provided as an input. This is
	/// used in cases where bundles are pre-determined by marking instructions
	/// with 'InsideBundle' marker. It returns the MBB instruction iterator that
	/// points to the end of the bundle.
	MachineBasicBlock::instr_iterator
	llvm::finalizeBundle(MachineBasicBlock &MBB,
	MachineBasicBlock::instr_iterator FirstMI) {
	MachineBasicBlock::instr_iterator E = MBB.instr_end();
	MachineBasicBlock::instr_iterator LastMI = std::next(FirstMI);
	while (LastMI != E && LastMI->isInsideBundle())
	++LastMI;
	finalizeBundle(MBB, FirstMI, LastMI);
	return LastMI;
	}

	/// finalizeBundles - Finalize instruction bundles in the specified
	/// MachineFunction. Return true if any bundles are finalized.
	bool llvm::finalizeBundles(MachineFunction &MF) {
	bool Changed = false;
	for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
	MachineBasicBlock &MBB = *I;
	MachineBasicBlock::instr_iterator MII = MBB.instr_begin();
	MachineBasicBlock::instr_iterator MIE = MBB.instr_end();
	if (MII == MIE)
	continue;
	assert(!MII->isInsideBundle() &&
	"First instr cannot be inside bundle before finalization!");

	for (++MII; MII != MIE; ) {
	if (!MII->isInsideBundle())
	++MII;
	else {
	MII = finalizeBundle(MBB, std::prev(MII));
	Changed = true;
	}
	}
	}

	return Changed;
	}

	//===----------------------------------------------------------------------===//
	// MachineOperand iterator
	//===----------------------------------------------------------------------===//

	MachineOperandIteratorBase::VirtRegInfo
	MachineOperandIteratorBase::analyzeVirtReg(unsigned Reg,
	SmallVectorImpl<std::pair<MachineInstr, unsigned> > Ops) {
	VirtRegInfo RI = { false, false, false };
	for(; isValid(); ++*this) {
	MachineOperand &MO = deref();
	if (!MO.isReg() \|\| MO.getReg() != Reg)
	continue;

	// Remember each (MI, OpNo) that refers to Reg.
	if (Ops)
	Ops->push_back(std::make_pair(MO.getParent(), getOperandNo()));

	// Both defs and uses can read virtual registers.
	if (MO.readsReg()) {
	RI.Reads = true;
	if (MO.isDef())
	RI.Tied = true;
	}

	// Only defs can write.
	if (MO.isDef())
	RI.Writes = true;
	else if (!RI.Tied && MO.getParent()->isRegTiedToDefOperand(getOperandNo()))
	RI.Tied = true;
	}
	return RI;
	}

	MachineOperandIteratorBase::PhysRegInfo
	MachineOperandIteratorBase::analyzePhysReg(unsigned Reg,
	const TargetRegisterInfo *TRI) {
	bool AllDefsDead = true;
	PhysRegInfo PRI = {false, false, false, false, false, false, false, false};

	assert(TargetRegisterInfo::isPhysicalRegister(Reg) &&
	"analyzePhysReg not given a physical register!");
	for (; isValid(); ++*this) {
	MachineOperand &MO = deref();

	if (MO.isRegMask() && MO.clobbersPhysReg(Reg)) {
	PRI.Clobbered = true;
	continue;
	}

	if (!MO.isReg())
	continue;

	unsigned MOReg = MO.getReg();
	if (!MOReg \|\| !TargetRegisterInfo::isPhysicalRegister(MOReg))
	continue;

	if (!TRI->regsOverlap(MOReg, Reg))
	continue;

	bool Covered = TRI->isSuperRegisterEq(Reg, MOReg);
	if (MO.readsReg()) {
	PRI.Read = true;
	if (Covered) {
	PRI.FullyRead = true;
	if (MO.isKill())
	PRI.Killed = true;
	}
	} else if (MO.isDef()) {
	PRI.Defined = true;
	if (Covered)
	PRI.FullyDefined = true;
	if (!MO.isDead())
	AllDefsDead = false;
	}
	}

	if (AllDefsDead) {
	if (PRI.FullyDefined \|\| PRI.Clobbered)
	PRI.DeadDef = true;
	else if (PRI.Defined)
	PRI.PartialDeadDef = true;
	}

	return PRI;
	}