/// joins them and returns true.
bool SimpleJoin(LiveInterval &LHS, LiveInterval &RHS);
- /// Return true if the two specified registers belong to different
- /// register classes. The registers may be either phys or virt regs.
- bool differingRegisterClasses(unsigned RegA, unsigned RegB) const;
+ /// Return true if the two specified registers belong to different register
+ /// classes. The registers may be either phys or virt regs. In the
+ /// case where both registers are virtual registers, it would also returns
+ /// true by reference the RegB register class in SubRC if it is a subset of
+ /// RegA's register class.
+ bool differingRegisterClasses(unsigned RegA, unsigned RegB,
+ const TargetRegisterClass *&SubRC) const;
/// AdjustCopiesBackFrom - We found a non-trivially-coalescable copy. If
/// identity copies so they will be removed.
void RemoveCopiesFromValNo(LiveInterval &li, VNInfo *VNI);
+ /// isProfitableToCoalesceToSubRC - Given that register class of DstReg is
+ /// a subset of the register class of SrcReg, return true if it's profitable
+ /// to coalesce the two registers.
+ bool isProfitableToCoalesceToSubRC(unsigned SrcReg, unsigned DstReg,
+ MachineBasicBlock *MBB);
+
/// RangeIsDefinedByCopyFromReg - Return true if the specified live range of
/// the specified live interval is defined by a copy from the specified
/// register.