+ /// 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);
+
+ /// HasIncompatibleSubRegDefUse - If we are trying to coalesce a virtual
+ /// register with a physical register, check if any of the virtual register
+ /// operand is a sub-register use or def. If so, make sure it won't result
+ /// in an illegal extract_subreg or insert_subreg instruction.
+ bool HasIncompatibleSubRegDefUse(MachineInstr *CopyMI,
+ unsigned VirtReg, unsigned PhysReg);
+