+ // Register unit functions.
+ //
+ // Fixed interference occurs when MachineInstrs use physregs directly
+ // instead of virtual registers. This typically happens when passing
+ // arguments to a function call, or when instructions require operands in
+ // fixed registers.
+ //
+ // Each physreg has one or more register units, see MCRegisterInfo. We
+ // track liveness per register unit to handle aliasing registers more
+ // efficiently.
+
+ /// getRegUnit - Return the live range for Unit.
+ /// It will be computed if it doesn't exist.
+ LiveInterval &getRegUnit(unsigned Unit) {
+ LiveInterval *LI = RegUnitIntervals[Unit];
+ if (!LI) {
+ // Compute missing ranges on demand.
+ RegUnitIntervals[Unit] = LI = new LiveInterval(Unit, HUGE_VALF);
+ computeRegUnitInterval(LI);
+ }
+ return *LI;
+ }
+
+ /// getCachedRegUnit - Return the live range for Unit if it has already
+ /// been computed, or NULL if it hasn't been computed yet.
+ LiveInterval *getCachedRegUnit(unsigned Unit) {
+ return RegUnitIntervals[Unit];
+ }
+