Re: [patch] Fix behavior of TER on unrolled loops

Re: [patch] Fix behavior of TER on unrolled loops

[Paolo Bonzini]

> Maybe everyone else manages to get good code without something like
> TER.

That's because we lack other things that people have, like a sane 
instruction selection and expression reordering pass: other compilers 
probably have something akin to TER as part of instruction selection. 
Like many other parts of GCC (right Steven? ;-) TER is not evil by 
itself -- it is as part of IR lowering.

I think Zdenek's patch is fine, because *everything* in TER is a hack.

> Zdenek, maybe you could you try and see if enabling pre-regalloc
> scheduling would also make this particular problem you're seeing go
> away, just as an experiment...

Couldn't it also make it much worse?

Paolo

Re: [patch] Fix behavior of TER on unrolled loops

[Steven Bosscher]

On Monday 22 August 2005 09:28, Paolo Bonzini wrote:
> I think Zdenek's patch is fine, because *everything* in TER is a hack.

My thoughts exactly ;-)

> > Zdenek, maybe you could you try and see if enabling pre-regalloc
> > scheduling would also make this particular problem you're seeing go
> > away, just as an experiment...
>
> Couldn't it also make it much worse?

Depends on what the scheduler does with the memory references
vs. register pressure.  I have no idea.

Gr.
Steven