Graph coloring for register allocation?

[Michael Matz]

Hi,

On Wed, 24 Jan 2001, Daniel Berlin wrote:
> > SMALL_REGISTER_CLASSES (and therefore all kinds of cruft all over the place).
> > Inability to run the scheduler before register allocation on some machines.
> 
> Unless i'm mistaken, all the papers i've looked at(save one or two, i
> think Chow and Hennessy didn't, it's hard to recall) require that
> scheduling be run before register allocation.

There is still no good knowledge how the connection between RA and
scheduling is. Either the papers develop a merged algorithm for RA and
scheduling, or they run scheduling before and after RA. Exclusively
running it before wouldn't make sense, as spill insertions would destroy
(or change) dependence relationship and therefore scheduling assumbptions,
and if there was no spill insertion, running scheduling after RA would
make no difference. So, we would still have sched and sched2.


Ciao,
Michael.