Mail Archives: pgcc/1998/07/13/16:03:45
Hello,
I compared speeds between compilers for my chess program at my pentium pro
200Mhz running linux.
Speed of 2.7.2 is 10% slower than msvc++
Now the weird thing: 2.8.1 is *exactly* as fast as 2.7.2, no matter what
optimizations i give it. This is weird.
I tried a bunch of different optimizations, starting with:
-O2 -mcpu=i686 -march=i686 -fomit-frame-pointer --fastmath
Note that in chessprograms FPU isn't used at all. Just integer instructions.
Now bob hyatt advised me to use
-O
This gave same result. No speed ups.
Then before that already Steffen A. Jacob told me to use -O6,
so next run was with
-O6 -mcpu=i686
This didn'thelp either. All about the same speed. Perhaps 0.0x% faster or
slower, but no more than that.
The normal -O2 also didn't give anything.
How comes gcc 2.8.1 which does allow pentium pro optimization and
instruction scheduling isn't faster than a 486 optimizing compiler?
Then i tried to install pgcc, but this compiler gives all kind of header
files errors. I installed it over 2.8.1 version pgcc-2.91.34
And it says so if i do gcc --version.
However it doesn't compile!
It forgot probably to replace the header files.
How to fix this, what do i need to ftp?
Vincent
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