DontCare, ///< Block doesn't care / variable not live.
PrefReg, ///< Block entry/exit prefers a register.
PrefSpill, ///< Block entry/exit prefers a stack slot.
DontCare, ///< Block doesn't care / variable not live.
PrefReg, ///< Block entry/exit prefers a register.
PrefSpill, ///< Block entry/exit prefers a stack slot.