Re: egcs 1.1 performance report

[Toon Moene <toon at moene dot indiv dot nluug dot nl>]

>  Thought some folks would be interested in seeing how 1.1
>  compares with 1.0 performance-wise.  The following is
>  the result of Spec95 run on my home machine, as described
>  below.

>  Executive summary is that we do a smidgen better, but
>  nothing to brag about.

>  In absolute terms, it is also nothing to brag about, as
>  both SpecINT and SpecFP are about 60% of what they ought
>  to be for my hardware.

BTW, do any of the SPECfp95 programs spend significant time doing  
complex arithmetic ?  I've been in a rather depressing dialog with  
someone from South Korea who shows that for such code egcs/g77 can  
easily be 2.5 times slower than Digital Fortran on the same  
hardware.

The simple code put forward by Mr. Rowe in

http://www.cygnus.com/ml/egcs-bugs/1998-Apr/0117.html

and which I showed is twice as fast on my m68k when using  
-fno-emulate-complex

http://www.cygnus.com/ml/egcs-bugs/1998-Apr/0245.html

gets a 1.5 x speedup on a 500 Mhz 21164A using that compilation flag.

The downside, of course, is that this only works by pure chance - a  
lot of complex code doesn't compile correctly when using gcc's  
SCmode and DCmode (which is what -fno-emulate-complex boils down  
to).

Cheers,
Toon.

PS: My conclusion about the NEXT crashing running LAPACK's selftests
    was completely wrong:  Someone in the know pointed out to me that
    the frame format error in the panic message was due to an unknown
    stack frame encountered during a floating point emulation trap.
    It seems that early 68040's do not always behave according to
    the datasheets ....