"Amker.Cheng" <amker.ch...@gmail.com> writes: > I'm currently studying implementation of instruction sched in gcc. > > it is possible to schedule insns directly from queue in case > there is nothing better to do and there are still vacant dispatch slots > in the current cycle. > > Gcc only does this work in the second pass, but what's the point? > Is it wrong or just not necessary in the first sched pass?
The first scheduling pass runs before register allocation and reload so it's going to get generally trashed anyhow. There no point to being very precise in the first pass, it's just a rough approximation. Ian
