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Re: SPECfp95: Huge performance loss with -fnew-ra?
- From: Michael Matz <matz at suse dot de>
- To: Daniel Berlin <dberlin at dberlin dot org>
- Cc: Diego Novillo <dnovillo at redhat dot com>, <gcc at gcc dot gnu dot org>
- Date: Tue, 23 Jul 2002 12:13:14 +0200 (CEST)
- Subject: Re: SPECfp95: Huge performance loss with -fnew-ra?
Hi,
On Mon, 22 Jul 2002, Daniel Berlin wrote:
> > I am not sure at the moment if it's the new register allocator by
> > itself or some combination of -fnew-ra and some other change.
>
> No, it's the new-ra, i'm sure.
Me too ;)
> In particular, Michael, the GENERAL_REGS change you mad (instead
> of the old ALL_REGS) guarantees we'll always spill float_regs,
Yes, unfortunately. I think for the time being I'll just introduce a new
class of regs of potential spill temporaries. These often would be
ALL_REGS, but e.g. on x86 would exclude MMX_REGS.
The real fix (webclass) is in the works, that's why I ignored the possible
decrease in performance for now. But I'm not comfortable with the current
SPECfp numbers, so ... ;)
Ciao,
Michael.