On 08/30/2017 09:41 AM, Richard Sandiford wrote: > > Even then I don't think we could ever have SET_SRC and SET_DEST being > different. The extension has to be explicit in the source. Yea, you should still have the same mode for the SET_SRC and SET_DEST. It's just that the operands underneath may have different modes.
ie (set (reg:SI) (zero_extend:SI (reg:HI)) So the SET_SRC/SET_DEST have the same modes, but the operands presented to the allocators and reloaders have different modes. The only reason I remember this being an "interesting" case is because in the old allocator (pre-IRA) we were not good at tying objects of different sizes. Jeff