//
// This file declares the machine register scavenger class. It can provide
// information such as unused register at any point in a machine basic block.
-// It also provides a mechanism to make registers availbale by evicting them
+// It also provides a mechanism to make registers available by evicting them
// to spill slots.
//
//===----------------------------------------------------------------------===//
MachineRegisterInfo* MRI;
MachineBasicBlock *MBB;
MachineBasicBlock::iterator MBBI;
- unsigned NumPhysRegs;
+ unsigned NumRegUnits;
- /// Tracking - True if RegScavenger is currently tracking the liveness of
- /// registers.
+ /// True if RegScavenger is currently tracking the liveness of registers.
bool Tracking;
/// Information on scavenged registers (held in a spill slot).
/// A vector of information on scavenged registers.
SmallVector<ScavengedInfo, 2> Scavenged;
- /// CalleeSavedrRegs - A bitvector of callee saved registers for the target.
- ///
- BitVector CalleeSavedRegs;
-
- /// RegsAvailable - The current state of all the physical registers immediately
- /// before MBBI. One bit per physical register. If bit is set that means it's
- /// available, unset means the register is currently being used.
- BitVector RegsAvailable;
+ /// The current state of each reg unit immediately before MBBI.
+ /// One bit per register unit. If bit is not set it means any
+ /// register containing that register unit is currently being used.
+ BitVector RegUnitsAvailable;
// These BitVectors are only used internally to forward(). They are members
// to avoid frequent reallocations.
- BitVector KillRegs, DefRegs;
+ BitVector KillRegUnits, DefRegUnits;
+ BitVector TmpRegUnits;
public:
RegScavenger()
- : MBB(nullptr), NumPhysRegs(0), Tracking(false) {}
+ : MBB(nullptr), NumRegUnits(0), Tracking(false) {}
- /// enterBasicBlock - Start tracking liveness from the begin of the specific
- /// basic block.
+ /// Start tracking liveness from the begin of the specific basic block.
void enterBasicBlock(MachineBasicBlock *mbb);
- /// initRegState - allow resetting register state info for multiple
- /// passes over/within the same function.
- void initRegState();
-
- /// forward - Move the internal MBB iterator and update register states.
+ /// Move the internal MBB iterator and update register states.
void forward();
- /// forward - Move the internal MBB iterator and update register states until
+ /// Move the internal MBB iterator and update register states until
/// it has processed the specific iterator.
void forward(MachineBasicBlock::iterator I) {
if (!Tracking && MBB->begin() != I) forward();
while (MBBI != I) unprocess();
}
- /// skipTo - Move the internal MBB iterator but do not update register states.
+ /// Move the internal MBB iterator but do not update register states.
void skipTo(MachineBasicBlock::iterator I) {
if (I == MachineBasicBlock::iterator(nullptr))
Tracking = false;
MBBI = I;
}
- MachineBasicBlock::iterator getCurrentPosition() const {
- return MBBI;
- }
+ MachineBasicBlock::iterator getCurrentPosition() const { return MBBI; }
- /// getRegsUsed - return all registers currently in use in used.
- void getRegsUsed(BitVector &used, bool includeReserved);
+ /// Return if a specific register is currently used.
+ bool isRegUsed(unsigned Reg, bool includeReserved = true) const;
- /// getRegsAvailable - Return all available registers in the register class
- /// in Mask.
+ /// Return all available registers in the register class in Mask.
BitVector getRegsAvailable(const TargetRegisterClass *RC);
- /// FindUnusedReg - Find a unused register of the specified register class.
+ /// Find an unused register of the specified register class.
/// Return 0 if none is found.
unsigned FindUnusedReg(const TargetRegisterClass *RegClass) const;
A.push_back(I->FrameIndex);
}
- /// scavengeRegister - Make a register of the specific register class
+ /// Make a register of the specific register class
/// available and do the appropriate bookkeeping. SPAdj is the stack
/// adjustment due to call frame, it's passed along to eliminateFrameIndex().
/// Returns the scavenged register.
return scavengeRegister(RegClass, MBBI, SPAdj);
}
- /// setUsed - Tell the scavenger a register is used.
- ///
- void setUsed(unsigned Reg);
+ /// Tell the scavenger a register is used.
+ void setRegUsed(unsigned Reg, LaneBitmask LaneMask = ~0u);
private:
- /// isReserved - Returns true if a register is reserved. It is never "unused".
+ /// Returns true if a register is reserved. It is never "unused".
bool isReserved(unsigned Reg) const { return MRI->isReserved(Reg); }
- /// isUsed - Test if a register is currently being used. When called by the
- /// isAliasUsed function, we only check isReserved if this is the original
- /// register, not an alias register.
+ /// setUsed / setUnused - Mark the state of one or a number of register units.
///
- bool isUsed(unsigned Reg, bool CheckReserved = true) const {
- return !RegsAvailable.test(Reg) || (CheckReserved && isReserved(Reg));
+ void setUsed(BitVector &RegUnits) {
+ RegUnitsAvailable.reset(RegUnits);
}
-
- /// isAliasUsed - Is Reg or an alias currently in use?
- bool isAliasUsed(unsigned Reg) const;
-
- /// setUsed / setUnused - Mark the state of one or a number of registers.
- ///
- void setUsed(BitVector &Regs) {
- RegsAvailable.reset(Regs);
- }
- void setUnused(BitVector &Regs) {
- RegsAvailable |= Regs;
+ void setUnused(BitVector &RegUnits) {
+ RegUnitsAvailable |= RegUnits;
}
- /// Processes the current instruction and fill the KillRegs and DefRegs bit
- /// vectors.
+ /// Processes the current instruction and fill the KillRegUnits and
+ /// DefRegUnits bit vectors.
void determineKillsAndDefs();
- /// Add Reg and all its sub-registers to BV.
- void addRegWithSubRegs(BitVector &BV, unsigned Reg);
+ /// Add all Reg Units that Reg contains to BV.
+ void addRegUnits(BitVector &BV, unsigned Reg);
- /// findSurvivorReg - Return the candidate register that is unused for the
- /// longest after StartMI. UseMI is set to the instruction where the search
- /// stopped.
+ /// Return the candidate register that is unused for the longest after
+ /// StartMI. UseMI is set to the instruction where the search stopped.
///
/// No more than InstrLimit instructions are inspected.
unsigned findSurvivorReg(MachineBasicBlock::iterator StartMI,
unsigned InstrLimit,
MachineBasicBlock::iterator &UseMI);
+ /// Allow resetting register state info for multiple
+ /// passes over/within the same function.
+ void initRegState();
};
} // End llvm namespace
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