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[mips] Use class RegDefsUses to track register defs and uses.

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No functionality change.

llvm-svn: 176070
This commit is contained in:
Akira Hatanaka 2013-02-26 01:30:05 +00:00
parent 5d41dc7229
commit 02e5e13e00
1 changed files with 82 additions and 89 deletions
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171
lib/Target/Mips/MipsDelaySlotFiller.cpp
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@ -44,6 +44,23 @@ static cl::opt<bool> SkipDelaySlotFiller(
cl::Hidden);
namespace {
class RegDefsUses {
public:
RegDefsUses(TargetMachine &TM);
void init(const MachineInstr &MI);
bool update(const MachineInstr &MI, unsigned Begin, unsigned End);
private:
bool checkRegDefsUses(BitVector &NewDefs, BitVector &NewUses, unsigned Reg,
bool IsDef) const;
/// Returns true if Reg or its alias is in RegSet.
bool isRegInSet(const BitVector &RegSet, unsigned Reg) const;
const TargetRegisterInfo &TRI;
BitVector Defs, Uses;
};
class Filler : public MachineFunctionPass {
public:
Filler(TargetMachine &tm)
@ -70,26 +87,11 @@ namespace {
bool runOnMachineBasicBlock(MachineBasicBlock &MBB);
/// Initialize RegDefs and RegUses.
void initRegDefsUses(const MachineInstr &MI, BitVector &RegDefs,
BitVector &RegUses) const;
bool isRegInSet(const BitVector &RegSet, unsigned Reg) const;
bool checkRegDefsUses(const BitVector &RegDefs, const BitVector &RegUses,
BitVector &NewDefs, BitVector &NewUses,
unsigned Reg, bool IsDef) const;
bool checkRegDefsUses(BitVector &RegDefs, BitVector &RegUses,
const MachineInstr &MI, unsigned Begin,
unsigned End) const;
/// This function checks if it is valid to move Candidate to the delay slot
/// and returns true if it isn't. It also updates load and store flags and
/// register defs and uses.
bool delayHasHazard(const MachineInstr &Candidate, bool &SawLoad,
bool &SawStore, BitVector &RegDefs,
BitVector &RegUses) const;
bool &SawStore, RegDefsUses &RegDU) const;
bool findDelayInstr(MachineBasicBlock &MBB, Iter slot, Iter &Filler) const;
@ -103,6 +105,65 @@ namespace {
char Filler::ID = 0;
} // end of anonymous namespace
RegDefsUses::RegDefsUses(TargetMachine &TM)
: TRI(*TM.getRegisterInfo()), Defs(TRI.getNumRegs(), false),
Uses(TRI.getNumRegs(), false) {}
void RegDefsUses::init(const MachineInstr &MI) {
// Add all register operands which are explicit and non-variadic.
update(MI, 0, MI.getDesc().getNumOperands());
// If MI is a call, add RA to Defs to prevent users of RA from going into
// delay slot.
if (MI.isCall())
Defs.set(Mips::RA);
// Add all implicit register operands of branch instructions except
// register AT.
if (MI.isBranch()) {
update(MI, MI.getDesc().getNumOperands(), MI.getNumOperands());
Defs.reset(Mips::AT);
}
}
bool RegDefsUses::update(const MachineInstr &MI, unsigned Begin, unsigned End) {
BitVector NewDefs(TRI.getNumRegs()), NewUses(TRI.getNumRegs());
bool HasHazard = false;
for (unsigned I = Begin; I != End; ++I) {
const MachineOperand &MO = MI.getOperand(I);
if (MO.isReg() && MO.getReg())
HasHazard |= checkRegDefsUses(NewDefs, NewUses, MO.getReg(), MO.isDef());
}
Defs |= NewDefs;
Uses |= NewUses;
return HasHazard;
}
bool RegDefsUses::checkRegDefsUses(BitVector &NewDefs, BitVector &NewUses,
unsigned Reg, bool IsDef) const {
if (IsDef) {
NewDefs.set(Reg);
// check whether Reg has already been defined or used.
return (isRegInSet(Defs, Reg) || isRegInSet(Uses, Reg));
}
NewUses.set(Reg);
// check whether Reg has already been defined.
return isRegInSet(Defs, Reg);
}
bool RegDefsUses::isRegInSet(const BitVector &RegSet, unsigned Reg) const {
// Check Reg and all aliased Registers.
for (MCRegAliasIterator AI(Reg, &TRI, true); AI.isValid(); ++AI)
if (RegSet.test(*AI))
return true;
return false;
}
/// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
/// We assume there is only one delay slot per delayed instruction.
bool Filler::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
@ -139,10 +200,9 @@ FunctionPass *llvm::createMipsDelaySlotFillerPass(MipsTargetMachine &tm) {
bool Filler::findDelayInstr(MachineBasicBlock &MBB, Iter Slot,
Iter &Filler) const {
unsigned NumRegs = TM.getRegisterInfo()->getNumRegs();
BitVector RegDefs(NumRegs), RegUses(NumRegs);
RegDefsUses RegDU(TM);
initRegDefsUses(*Slot, RegDefs, RegUses);
RegDU.init(*Slot);
bool SawLoad = false;
bool SawStore = false;
@ -155,7 +215,7 @@ bool Filler::findDelayInstr(MachineBasicBlock &MBB, Iter Slot,
if (terminateSearch(*I))
break;
if (delayHasHazard(*I, SawLoad, SawStore, RegDefs, RegUses))
if (delayHasHazard(*I, SawLoad, SawStore, RegDU))
continue;
Filler = llvm::next(I).base();
@ -165,45 +225,8 @@ bool Filler::findDelayInstr(MachineBasicBlock &MBB, Iter Slot,
return false;
}
bool Filler::checkRegDefsUses(const BitVector &RegDefs,
const BitVector &RegUses,
BitVector &NewDefs, BitVector &NewUses,
unsigned Reg, bool IsDef) const {
if (IsDef) {
NewDefs.set(Reg);
// check whether Reg has already been defined or used.
return (isRegInSet(RegDefs, Reg) || isRegInSet(RegUses, Reg));
}
NewUses.set(Reg);
// check whether Reg has already been defined.
return isRegInSet(RegDefs, Reg);
}
bool Filler::checkRegDefsUses(BitVector &RegDefs, BitVector &RegUses,
const MachineInstr &MI, unsigned Begin,
unsigned End) const {
unsigned NumRegs = TM.getRegisterInfo()->getNumRegs();
BitVector NewDefs(NumRegs), NewUses(NumRegs);
bool HasHazard = false;
for (unsigned I = Begin; I != End; ++I) {
const MachineOperand &MO = MI.getOperand(I);
if (MO.isReg() && MO.getReg())
HasHazard |= checkRegDefsUses(RegDefs, RegUses, NewDefs, NewUses,
MO.getReg(), MO.isDef());
}
RegDefs |= NewDefs;
RegUses |= NewUses;
return HasHazard;
}
bool Filler::delayHasHazard(const MachineInstr &Candidate, bool &SawLoad,
bool &SawStore, BitVector &RegDefs,
BitVector &RegUses) const {
bool &SawStore, RegDefsUses &RegDU) const {
bool HasHazard = (Candidate.isImplicitDef() || Candidate.isKill());
// Loads or stores cannot be moved past a store to the delay slot
@ -219,41 +242,11 @@ bool Filler::delayHasHazard(const MachineInstr &Candidate, bool &SawLoad,
assert((!Candidate.isCall() && !Candidate.isReturn()) &&
"Cannot put calls or returns in delay slot.");
HasHazard |= checkRegDefsUses(RegDefs, RegUses, Candidate, 0,
Candidate.getNumOperands());
HasHazard |= RegDU.update(Candidate, 0, Candidate.getNumOperands());
return HasHazard;
}
void Filler::initRegDefsUses(const MachineInstr &MI, BitVector &RegDefs,
BitVector &RegUses) const {
// Add all register operands which are explicit and non-variadic.
checkRegDefsUses(RegDefs, RegUses, MI, 0, MI.getDesc().getNumOperands());
// If MI is a call, add RA to RegDefs to prevent users of RA from going into
// delay slot.
if (MI.isCall())
RegDefs.set(Mips::RA);
// Add all implicit register operands of branch instructions except
// register AT.
if (MI.isBranch()) {
checkRegDefsUses(RegDefs, RegUses, MI, MI.getDesc().getNumOperands(),
MI.getNumOperands());
RegDefs.reset(Mips::AT);
}
}
//returns true if the Reg or its alias is in the RegSet.
bool Filler::isRegInSet(const BitVector &RegSet, unsigned Reg) const {
// Check Reg and all aliased Registers.
for (MCRegAliasIterator AI(Reg, TM.getRegisterInfo(), true);
AI.isValid(); ++AI)
if (RegSet.test(*AI))
return true;
return false;
}
bool Filler::terminateSearch(const MachineInstr &Candidate) const {
return (Candidate.isTerminator() || Candidate.isCall() ||
Candidate.isLabel() || Candidate.isInlineAsm() ||