llvm-project

8f62ad4e - TableGen: Support target specialized pseudoinstructions

TableGen: Support target specialized pseudoinstructions Allow a target to steal the definition of a generic pseudoinstruction and remap the operands. This works by defining a new instruction, which will simply swap out the emitted entry in the InstrInfo table. This is intended to eliminate the C++ half of the implementation of PointerLikeRegClass. With RegClassByHwMode, the remaining usecase for PointerLikeRegClass are the common codegen pseudoinstructions. Every target maintains its own copy of the generic pseudo operand definitions anyway, so we can stub out the register operands with an appropriate class instead of waiting for runtime resolution. In the future we could probably take this a bit further. For example, there is a similar problem for ADJCALLSTACKUP/DOWN since they depend on target register definitions for the stack pointer register.