On 03/20/2013 08:00 AM, Marc Glisse wrote: > Do you at least agree that vector-vector subregs make sense, or is that part > wrong as well?
You mean a V4SImode subreg of a V8SImode register, not just same-size casting? It makes logical sense, but I'm fairly sure you'll need a lot more surgery throughout the compiler to make that happen. I'm curious how a define_expand can fail in LRA, but your define_insn succeeds? Is the failure because of ix86_cannot_change_mode_class? Because that hook fairly well defines what subregs are valid. And if that says it isn't valid, then even having a define_insn that uses such is wrong. r~
