[fpc-pascal] Optimizer in 2.0

[Adrian Veith]

It shows with useless code like simple nested for .. to loops, but also 
with some more useful code like the attached RSA_Angriff from the C'T 
magazine.

My results are with:

fpc -Sd -OG3rp3 -XX RSA_Angriff_D5.dpr

5266 ms

with:

fpc -Sd -XX RSA_Angriff_D5.dpr

4844 ms

The unoptimized code is faster than the optimized code.

(BTW. I choosed an example where the Delphi compiler is really worse ;-) 
: 65953 ms)

Same picture with the whet.pas (whether or not the whetstone benchmark 
is useful) from your source distribution.

With optimization on:  7393.72 MIPS

With optimization off:  8368.20 MIPS

cheers,

Adrian.

Florian Klaempfl schrieb:

>Adrian Veith wrote:
>
>  
>
>>Hi,
>>
>>I am newbie with fpc (but not with pascal, which I use more than 20y now).
>>We have lot of existing delphi code, which some of it, I want to port to
>>new platforms - and fpc looks like the right tool for it. But I am
>>concerned about the speed. I did some basic benchmarks and it seems,
>>that the optimizers has no effect in the 2.0 compiler (or the code even
>>get's slower).
>>    
>>
>
>This shouldn't be the case in general, can you give examples or post the
>benchmark? And don't try with useless code, we don't care about optimziations
>which test only useless code which never happens in real programs.
>
>  
>
>>With the 1.9.8 compiler, the same code executes 4 times quicker - what
>>happend (or what do I wrong) ?
>>
>>For optimizing I use the -OG3rp3 switch  - is it still valid ?
>>
>>Thanks,
>>
>>Adrian.
>>
>>
>>
>>_______________________________________________
>>fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>>http://lists.freepascal.org/mailman/listinfo/fpc-pascal
>>    
>>
>
>
>_______________________________________________
>fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>http://lists.freepascal.org/mailman/listinfo/fpc-pascal
>
>  
>
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