- /// ReservedRegisters - This vector keeps track of which registers
- /// are reserved register which are not allocatable by the target machine.
- /// We can not track liveness for values that are in this set.
- ///
- BitVector ReservedRegisters;
+ /// PHIJoins - list of virtual registers that are PHI joins. These registers
+ /// may have multiple definitions, and they require special handling when
+ /// building live intervals.
+ SparseBitVector<> PHIJoins;