On Wed, Mar 15, 2017 at 12:09:18AM +0100, Bernd Schmidt wrote: > I suppose at the moment we don't do 2->2 combinations, so we could > conditionalize this on having an i1. You suppose wrong. If one of the resulting insns is set_noop_p then 2->2 is allowed, for example. Also in the hopefully not so far future we will allow 2->2 in general. Segher