///
void setRegClass(unsigned Reg, const TargetRegisterClass *RC);
+ /// constrainRegClass - Constrain the register class of the specified virtual
+ /// register to be a common subclass of RC and the current register class.
+ /// Return the new register class, or NULL if no such class exists.
+ /// This should only be used when the constraint is known to be trivial, like
+ /// GR32 -> GR32_NOSP. Beware of increasing register pressure.
+ const TargetRegisterClass *constrainRegClass(unsigned Reg,
+ const TargetRegisterClass *RC);
+
/// createVirtualRegister - Create and return a new virtual register in the
/// function with the specified register class.
///