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Re: How to clean up i386 machine description?
- To: hubicka at horac dot ta dot jcu dot cz (Jan Hubicka)
- Subject: Re: How to clean up i386 machine description?
- From: Joern Rennecke <amylaar at cygnus dot co dot uk>
- Date: Sat, 14 Nov 1998 06:48:54 +0000 (GMT)
- Cc: amylaar at cygnus dot co dot uk, rth at cygnus dot com, howell at cs dot stanford dot edu, law at cygnus dot com, pcg at goof dot com, egcs at cygnus dot com
> > If you need to order instruction alternatives differently for different
> > CPUs or use different constraint modifiers so that the alternative
> > selection is changed, currently the only way is to have different
> > patterns for the different CPUs.
> What do you mean by constraint modifier?
Stuff like ?, !, # and * can be used to fine-tune register allocation
and alternative selection. Look at md.texi for details.