On Wed, Sep 11, 2019 at 02:18:36PM +0200, Eric Botcazou wrote: > > What does it mean for > > (set (reg:QI) (const_int -128)) > > for example? This is the canonical form of moving positive 128 into a > > register as well, of course. > > Nothing, since word_register_operation_p returns false on CONST_INTs . > > > W_R_O needs many more restrictions if it can work at all, but those aren't > > documented. > > The problematic issue is more basic and pertains to mere SUBREGs.
I'd say this is more basic, but heh... It's an example. If it isn't documented what W_R_O really *does*, how can we ever hope to make it works stably? Segher
