Message-ID:	<19990628160115.A32699@tabor.ta.jcu.cz>
Date:	Mon, 28 Jun 1999 16:01:15 +0200
From:	Jan Hubicka <hubicka AT ta DOT jcu DOT cz>
To:	djgpp-workers AT delorie DOT com
Subject:	Re: Regparm....
References:	<19990628010734 DOT 59338 AT atrey DOT karlin DOT mff DOT cuni DOT cz> <377779B4 DOT 8A30CE7D AT inti DOT gov DOT ar>
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On Mon, Jun 28, 1999 at 10:33:40AM -0300, salvador wrote:
> Jan Hubicka wrote:
> 
> > DJGPP seems to be ideal platform for testing this feature ...
> 
> Yes, djgpp is interesting for it.
> I must check with 2.95, but when I tested regparm with egcs 1.1.2 it was slower than push/pop, why? egcs is very idiot choosing registers so after all was using more
> instructions instead of less.
Because libraries are shorter, I would expect this is gone (at least there can be fewer
instructions even when I take into account the fact, that mov (mem) is longer than mov reg.
Because of tons of changes in reload and inheritance, I would expect gcc to do better job now.
It can improve in future, so we can be prepared for it :)
> 
> [snip]
> 
> > hello world, zlib, pnglib and some other stuff seems to work well. There are
> > problems with longjmp, profiling and debugging, but they was likely to happen.
> 
> Did you try with -gstabs3+ ? It can generate debug information for variables optimized to registers so perhaps can help here.
Sounds cool, so only longjmp and profiling can be problem..
> 
> > So please let me know your ideas.
> > Just last information that might interest you is the size of stripped
> > libc compiled in various regparms:
> > -mregparm=0  326kb
> > -mregparm=1  323kb
> > -mregparm=2  321kb
> > -mregparm=3  320kb
> > so gcc seems to generate best code for regparm=3 now. This has changed since
> > the 2.7.2 times, that liked the regparm=1 the best...
> > So maybe it will make sense to only use -mregparm=0 and -mregparm=3 code.
> 
> Do you have these libraries available for download? I could try the BYTE benchmarks linking with it.
Just uploading them to ftp://ftp.ta.jcu.cz/pub/linux/hubicka/experimental/reglibs.tgz
You will also need to apply the patch to include files I sent in the first letter.
Hope they will be stable enought for the benchmark, looking forward for the results!

Honza
> 
> SET
> 
> --
> Salvador Eduardo Tropea (SET). (Electronics Engineer)
> Visit my home page: http://welcome.to/SetSoft or
> http://www.geocities.com/SiliconValley/Vista/6552/
> Alternative e-mail: set-soft AT usa DOT net set AT computer DOT org
>                     set AT ieee DOT org set-soft AT bigfoot DOT com
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> 
> 

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