Loop unrolling-related SPEC regressions?

[Michael Matz]

Hi,

On Thu, 7 Feb 2002, Andreas Jaeger wrote:

> > Intelligent use of profiling info from the first pass is
> > important.  You'll see the published numbers do this.
> > Last time I looked gcc used this only for branch
> > straightening; it can also be used effectively to
> > drive inlining and register allocation.
>
> AFAIK the infrastructure is there, it only needs to be used for
> inlining - and also in the new register allocator.  Michal, is this
> possible?

In fact if the numbers I base decisions in the allocator on, are itself
based on profiling, then the allocator can already be profile-guided.
Basically what I need is only cost estimations for basic blocks (i.e. how
often they are run compared to the other blocks in the function).  I don't
care if they are estimated statically from loop structure or precisely
from profiling.


Ciao,
Michael.