negative latencies

[shmeel gutl <shmeelgutl at shmuelhome dot mine dot nu>]

Are there hooks in gcc to deal with negative latencies? In other words, 
an architecture that permits an instruction to use a result from an 
instruction that will be issued later.

At first glance it seems that it will will break a few things.
1) The definition of dependencies cannot come from the simple ordering 
of rtl.
2) The scheduling problem starts to look like "get off the train 3 stops 
before me".
3) The definition of live ranges needs to use actual instruction timing 
information, not just instruction sequencing.

The hooks in the scheduler seem to be enough to stop damage but not 
enough to take advantage of this "feature".

Thanks