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[mips] Use class RegDefsUses to track register defs and uses.
No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176070 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -44,6 +44,23 @@ static cl::opt<bool> SkipDelaySlotFiller(
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cl::Hidden);
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namespace {
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class RegDefsUses {
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public:
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RegDefsUses(TargetMachine &TM);
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void init(const MachineInstr &MI);
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bool update(const MachineInstr &MI, unsigned Begin, unsigned End);
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private:
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bool checkRegDefsUses(BitVector &NewDefs, BitVector &NewUses, unsigned Reg,
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bool IsDef) const;
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/// Returns true if Reg or its alias is in RegSet.
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bool isRegInSet(const BitVector &RegSet, unsigned Reg) const;
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const TargetRegisterInfo &TRI;
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BitVector Defs, Uses;
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};
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class Filler : public MachineFunctionPass {
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public:
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Filler(TargetMachine &tm)
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@ -70,26 +87,11 @@ namespace {
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bool runOnMachineBasicBlock(MachineBasicBlock &MBB);
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/// Initialize RegDefs and RegUses.
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void initRegDefsUses(const MachineInstr &MI, BitVector &RegDefs,
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BitVector &RegUses) const;
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bool isRegInSet(const BitVector &RegSet, unsigned Reg) const;
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bool checkRegDefsUses(const BitVector &RegDefs, const BitVector &RegUses,
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BitVector &NewDefs, BitVector &NewUses,
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unsigned Reg, bool IsDef) const;
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bool checkRegDefsUses(BitVector &RegDefs, BitVector &RegUses,
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const MachineInstr &MI, unsigned Begin,
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unsigned End) const;
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/// This function checks if it is valid to move Candidate to the delay slot
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/// and returns true if it isn't. It also updates load and store flags and
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/// register defs and uses.
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bool delayHasHazard(const MachineInstr &Candidate, bool &SawLoad,
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bool &SawStore, BitVector &RegDefs,
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BitVector &RegUses) const;
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bool &SawStore, RegDefsUses &RegDU) const;
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bool findDelayInstr(MachineBasicBlock &MBB, Iter slot, Iter &Filler) const;
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@ -103,6 +105,65 @@ namespace {
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char Filler::ID = 0;
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} // end of anonymous namespace
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RegDefsUses::RegDefsUses(TargetMachine &TM)
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: TRI(*TM.getRegisterInfo()), Defs(TRI.getNumRegs(), false),
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Uses(TRI.getNumRegs(), false) {}
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void RegDefsUses::init(const MachineInstr &MI) {
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// Add all register operands which are explicit and non-variadic.
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update(MI, 0, MI.getDesc().getNumOperands());
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// If MI is a call, add RA to Defs to prevent users of RA from going into
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// delay slot.
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if (MI.isCall())
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Defs.set(Mips::RA);
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// Add all implicit register operands of branch instructions except
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// register AT.
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if (MI.isBranch()) {
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update(MI, MI.getDesc().getNumOperands(), MI.getNumOperands());
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Defs.reset(Mips::AT);
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}
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}
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bool RegDefsUses::update(const MachineInstr &MI, unsigned Begin, unsigned End) {
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BitVector NewDefs(TRI.getNumRegs()), NewUses(TRI.getNumRegs());
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bool HasHazard = false;
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for (unsigned I = Begin; I != End; ++I) {
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const MachineOperand &MO = MI.getOperand(I);
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if (MO.isReg() && MO.getReg())
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HasHazard |= checkRegDefsUses(NewDefs, NewUses, MO.getReg(), MO.isDef());
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}
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Defs |= NewDefs;
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Uses |= NewUses;
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return HasHazard;
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}
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bool RegDefsUses::checkRegDefsUses(BitVector &NewDefs, BitVector &NewUses,
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unsigned Reg, bool IsDef) const {
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if (IsDef) {
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NewDefs.set(Reg);
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// check whether Reg has already been defined or used.
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return (isRegInSet(Defs, Reg) || isRegInSet(Uses, Reg));
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}
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NewUses.set(Reg);
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// check whether Reg has already been defined.
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return isRegInSet(Defs, Reg);
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}
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bool RegDefsUses::isRegInSet(const BitVector &RegSet, unsigned Reg) const {
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// Check Reg and all aliased Registers.
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for (MCRegAliasIterator AI(Reg, &TRI, true); AI.isValid(); ++AI)
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if (RegSet.test(*AI))
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return true;
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return false;
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}
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/// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
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/// We assume there is only one delay slot per delayed instruction.
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bool Filler::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
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@ -139,10 +200,9 @@ FunctionPass *llvm::createMipsDelaySlotFillerPass(MipsTargetMachine &tm) {
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bool Filler::findDelayInstr(MachineBasicBlock &MBB, Iter Slot,
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Iter &Filler) const {
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unsigned NumRegs = TM.getRegisterInfo()->getNumRegs();
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BitVector RegDefs(NumRegs), RegUses(NumRegs);
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RegDefsUses RegDU(TM);
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initRegDefsUses(*Slot, RegDefs, RegUses);
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RegDU.init(*Slot);
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bool SawLoad = false;
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bool SawStore = false;
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@ -155,7 +215,7 @@ bool Filler::findDelayInstr(MachineBasicBlock &MBB, Iter Slot,
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if (terminateSearch(*I))
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break;
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if (delayHasHazard(*I, SawLoad, SawStore, RegDefs, RegUses))
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if (delayHasHazard(*I, SawLoad, SawStore, RegDU))
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continue;
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Filler = llvm::next(I).base();
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@ -165,45 +225,8 @@ bool Filler::findDelayInstr(MachineBasicBlock &MBB, Iter Slot,
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return false;
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}
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bool Filler::checkRegDefsUses(const BitVector &RegDefs,
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const BitVector &RegUses,
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BitVector &NewDefs, BitVector &NewUses,
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unsigned Reg, bool IsDef) const {
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if (IsDef) {
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NewDefs.set(Reg);
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// check whether Reg has already been defined or used.
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return (isRegInSet(RegDefs, Reg) || isRegInSet(RegUses, Reg));
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}
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NewUses.set(Reg);
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// check whether Reg has already been defined.
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return isRegInSet(RegDefs, Reg);
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}
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bool Filler::checkRegDefsUses(BitVector &RegDefs, BitVector &RegUses,
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const MachineInstr &MI, unsigned Begin,
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unsigned End) const {
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unsigned NumRegs = TM.getRegisterInfo()->getNumRegs();
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BitVector NewDefs(NumRegs), NewUses(NumRegs);
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bool HasHazard = false;
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for (unsigned I = Begin; I != End; ++I) {
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const MachineOperand &MO = MI.getOperand(I);
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if (MO.isReg() && MO.getReg())
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HasHazard |= checkRegDefsUses(RegDefs, RegUses, NewDefs, NewUses,
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MO.getReg(), MO.isDef());
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}
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RegDefs |= NewDefs;
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RegUses |= NewUses;
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return HasHazard;
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}
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bool Filler::delayHasHazard(const MachineInstr &Candidate, bool &SawLoad,
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bool &SawStore, BitVector &RegDefs,
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BitVector &RegUses) const {
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bool &SawStore, RegDefsUses &RegDU) const {
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bool HasHazard = (Candidate.isImplicitDef() || Candidate.isKill());
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// Loads or stores cannot be moved past a store to the delay slot
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@ -219,41 +242,11 @@ bool Filler::delayHasHazard(const MachineInstr &Candidate, bool &SawLoad,
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assert((!Candidate.isCall() && !Candidate.isReturn()) &&
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"Cannot put calls or returns in delay slot.");
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HasHazard |= checkRegDefsUses(RegDefs, RegUses, Candidate, 0,
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Candidate.getNumOperands());
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HasHazard |= RegDU.update(Candidate, 0, Candidate.getNumOperands());
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return HasHazard;
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}
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void Filler::initRegDefsUses(const MachineInstr &MI, BitVector &RegDefs,
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BitVector &RegUses) const {
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// Add all register operands which are explicit and non-variadic.
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checkRegDefsUses(RegDefs, RegUses, MI, 0, MI.getDesc().getNumOperands());
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// If MI is a call, add RA to RegDefs to prevent users of RA from going into
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// delay slot.
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if (MI.isCall())
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RegDefs.set(Mips::RA);
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// Add all implicit register operands of branch instructions except
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// register AT.
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if (MI.isBranch()) {
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checkRegDefsUses(RegDefs, RegUses, MI, MI.getDesc().getNumOperands(),
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MI.getNumOperands());
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RegDefs.reset(Mips::AT);
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}
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}
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//returns true if the Reg or its alias is in the RegSet.
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bool Filler::isRegInSet(const BitVector &RegSet, unsigned Reg) const {
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// Check Reg and all aliased Registers.
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for (MCRegAliasIterator AI(Reg, TM.getRegisterInfo(), true);
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AI.isValid(); ++AI)
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if (RegSet.test(*AI))
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return true;
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return false;
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}
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bool Filler::terminateSearch(const MachineInstr &Candidate) const {
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return (Candidate.isTerminator() || Candidate.isCall() ||
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Candidate.isLabel() || Candidate.isInlineAsm() ||
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