Hi Juzhe,
in principle this seems ok to me but I wonder about: > We shouldn't worry about subreg:...VL_REGNUM since it's impossible > that we can have such situation, I think we allow this in legitimize_move for situations like (subreg:SI (reg:V4QI)). That was not added for correctness but optimization - are we sure we don't undo this optimization with that change? Regards Robin