[BENCHMARK] comparing GCC 3.4 and 4.0 on an AMD Athlon-XP 2500+

[Rene Rebe]

Hi all,

I have some preleminary benchmark results comparing 3.4(.3) with 4.0.0, 
including some optimization option permuations.

   http://exactcode.de/rene/hidden/gcc-article/2005-gcc-4.0/stat2-rt.png
   http://exactcode.de/rene/hidden/gcc-article/2005-gcc-4.0/stat2-bt.png

rt = runtime
bt = buildtime

-lu == -funroll-loops
-uaat == -funit-at-a-time
-vect == -ftree-vectorize
-oft == -fomit-frame-pointer
-x ==  -funroll-loops -fpeel-loops -fpeel-loops -funswitch-loops
        -ftree-vectorize -ftracer -fomit-frame-pointer

-x-uaat == -x + -uaat

A short summary:

4.0 seems to be very good at modern C++ code, especially involving a lot 
of templates.

The -Os switch's generated code speed degenerated by magnitudes for C++ 
code (look at Botan and tramp3d).

4.0 seems to have problems catching up at C code where 3.4(.3) was 
previously yielding good results - e.g openssl, libmad and gnupg seem to 
be a challenge for GCC.

Of course all hand written assembly was disabled in those benchmarks, to 
review what GCC is able to genereate out of the generic C code ...

Feedback welcome - yours,

-- 
René Rebe - Rubensstr. 64 - 12157 Berlin (Europe / Germany)
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