+ void setPhysRegUnused(unsigned Reg) {
+ UsedPhysRegMask.reset(Reg);
+ for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units)
+ UsedRegUnits.reset(*Units);
+ }
+
+
+ //===--------------------------------------------------------------------===//
+ // Reserved Register Info
+ //===--------------------------------------------------------------------===//
+ //
+ // The set of reserved registers must be invariant during register
+ // allocation. For example, the target cannot suddenly decide it needs a
+ // frame pointer when the register allocator has already used the frame
+ // pointer register for something else.
+ //
+ // These methods can be used by target hooks like hasFP() to avoid changing
+ // the reserved register set during register allocation.
+
+ /// freezeReservedRegs - Called by the register allocator to freeze the set
+ /// of reserved registers before allocation begins.
+ void freezeReservedRegs(const MachineFunction&);
+
+ /// reservedRegsFrozen - Returns true after freezeReservedRegs() was called
+ /// to ensure the set of reserved registers stays constant.
+ bool reservedRegsFrozen() const {
+ return !ReservedRegs.empty();
+ }
+
+ /// canReserveReg - Returns true if PhysReg can be used as a reserved
+ /// register. Any register can be reserved before freezeReservedRegs() is
+ /// called.
+ bool canReserveReg(unsigned PhysReg) const {
+ return !reservedRegsFrozen() || ReservedRegs.test(PhysReg);
+ }
+
+ /// getReservedRegs - Returns a reference to the frozen set of reserved
+ /// registers. This method should always be preferred to calling
+ /// TRI::getReservedRegs() when possible.
+ const BitVector &getReservedRegs() const {
+ assert(reservedRegsFrozen() &&
+ "Reserved registers haven't been frozen yet. "
+ "Use TRI::getReservedRegs().");
+ return ReservedRegs;
+ }
+
+ /// isReserved - Returns true when PhysReg is a reserved register.
+ ///
+ /// Reserved registers may belong to an allocatable register class, but the
+ /// target has explicitly requested that they are not used.
+ ///
+ bool isReserved(unsigned PhysReg) const {
+ return getReservedRegs().test(PhysReg);
+ }
+
+ /// isAllocatable - Returns true when PhysReg belongs to an allocatable
+ /// register class and it hasn't been reserved.
+ ///
+ /// Allocatable registers may show up in the allocation order of some virtual
+ /// register, so a register allocator needs to track its liveness and
+ /// availability.
+ bool isAllocatable(unsigned PhysReg) const {
+ return TRI->isInAllocatableClass(PhysReg) && !isReserved(PhysReg);
+ }