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Re: egcs 1.0 *faster* than Sun's C compiler!!!!


>>>>> "Harvey" == Harvey J Stein <hjstein@bfr.co.il> writes:


    Harvey> Sun, compiled with gcc -O3 -funroll-loops
    Harvey> -finline-functions -ffast-math -fomit-frame-pointer
    Harvey> -msupersparc 28.88user 0.27system 0:29.26elapsed 99%CPU

    Harvey> Sun, compiled with cc -fast -xO4 -xdepend -xchip=ultra
    Harvey> -xarch=v8plusa 39.86user 0.21system 0:40.15elapsed 99%CPU

    Harvey> Sun, compiled with cc -fast -xO5 -xdepend -xchip=ultra
    Harvey> -xarch=v8plusa 39.70user 0.17system 0:39.95elapsed 99%CPU

    Harvey> Alpha, compiled with gcc -O2 11.82user 0.15system
    Harvey> 0:12.08elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k

    Harvey> The sun is a 200mhz ultra-sparc.  The alpha is a 533mhz
    Harvey> alpha.


    Harvey> Is it typical that gcc optimizes *better* than Sun's C
    Harvey> compiler?

Well, SUNPro should be faster since you've pay for it. A major point
to argue about are the options to use. For example I don't what
-ffast-math does but what about enabling a simliar feature when
running SUNPro!? And why limit the instruction set to -xarch=v8plusa!?

My choice when running those tests is to iterate on set of options for
a certain compiler (and machine) in order to get the fastest run. This 
is rather time consuming and the results merly depend on the fact how
much you know aboutn the compiler.

--Marcus



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