Jeff Law <l...@redhat.com> writes: > Finding a way to drop the naked clobbers/uses would be a better way > forward. I'm a bit surprised we need them as much as we apparently do. > We're conflating issues a bit here though.
FWIW, I think they're a really useful feature. E.g. they help when modelling the lifetimes of multi-hard-reg pseudos that are accessed via subregs. Without them, we do a poor job tracking register lifetimes for things like ST3 and ST4 (g:3ba4ff4130903a3ded931d715a2204bd8834fe60). We might eventually be able to avoid some of that by using better subreg tracking, but I suspect there are always going to be cases in which clobber information inherited from gimple will be needed (or least work better). Also, the fact that gimple has essentially the same feature (for clobbers at least) suggests this might be one of those things that is bound to be invented if it doesn't already exist. ;-) Richard
