Le 21 oct. 2009 à 09:29, Gunnar Sletta a écrit :

> GCC is a lot worse than VC++, I've observed VC being up to 3x faster  
> in
> tight loops based for the same code in extreme cases, but the  
> difference
> doesn't bubble up to application level... Possibly a +/-10%  
> difference.
>
> Could it be that you are not getting SSE/MMX instructions on Mac? Are
> you on 10.4 by any chance?

The biggest problem with GCC on Mac is that the Apple version will not  
evolve beyond 4.2.1. Reason: Apple has rejected the GPL v3 licence,  
and so the engineers at Apple, that do maintain the GCC code for the  
Darwin target, are not even allowed to download or read the code of  
GCC beyond the last GPL v2 version. Meanwhile, Apple is pushing CLANG/ 
LLVM ahead.

As a consequence, Darwin has been downgraded from primary to secondary  
target for GCC.

Naturally, there is always the possibility to compile its own GCC  
4.3/4.4, but, starting at 4.5 there are some incompatibilities related  
to libgcc_s.

Vincent


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