- /// restoreScavengedReg - Restore scavenged by loading it back from the
- /// emergency spill slot. Mark it used.
- void restoreScavengedReg();
+ /// isReserved - Returns true if a register is reserved. It is never "unused".
+ bool isReserved(unsigned Reg) const { return ReservedRegs.test(Reg); }
+
+ /// isUsed / isUnused - Test if a register is currently being used.
+ ///
+ bool isUsed(unsigned Reg) const {
+ return !RegsAvailable.test(Reg) || ReservedRegs.test(Reg);
+ }
+
+ /// 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;
+ }
+
+ /// Add Reg and all its sub-registers to BV.
+ void addRegWithSubRegs(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.
+ ///
+ /// No more than InstrLimit instructions are inspected.
+ unsigned findSurvivorReg(MachineBasicBlock::iterator StartMI,
+ BitVector &Candidates,
+ unsigned InstrLimit,
+ MachineBasicBlock::iterator &UseMI);