Message-ID: <19990628140633.A32179@tabor.ta.jcu.cz>
Date: Mon, 28 Jun 1999 14:06:33 +0200
From: Jan Hubicka <hubicka AT ta DOT jcu DOT cz>
To: djgpp-workers AT delorie DOT com
Subject: Regparm...speed differences
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Reply-To: djgpp-workers AT delorie DOT com

Hi
I've mentioned large (100%) speedup for regparm library in qsort. This result was bogus, I've just
compared unoptimized library with optimized one.
I've done few simple test and the speed improvement for qsort sorting integers is 20%,
simple recursive function (do nothing) with one parameter speeds up for approx. 30%, aprox 80% faster
when have 3 parameters on my Pentium160 MMX.
"normal" code will probably not be affected much (except the cases where function calling overhead
still plays important role, such as reading using fgetc or 3d engines drawing small triangles using
non-inlined function). I am looking forward to get some graphics library (allegro) working with regparm
to see the effect. I think the graphics libraries are best candidates for speedup.

Some extra speedup and space saving can be to make -fomit-frame-pointerized regparm libraries for production
code. This might make sense, because debugging is broken anyway. Sparc does this when -fast option is used.


Honza