Optimising std::find on x86 and PPC

[Chris Jefferson]

Paolo Carlini wrote:

> Paolo Carlini wrote:
>
>> Besided what Gaby and Benjamin already replied, out of curiosity, 
>> what the loop
>> unroller is doing, right now?!? Nothing!?!
>
>
> More explicitly, and in the "right" spirit for the library: let's 
> suppose we remove completely any ad-hoc loop-unrolling by hand, can we 
> trust the loop-unroller to do a decent work both on x86-linux and 
> darwin-powerpc? This is something worth
> investigating, IMHO... and in case the loop unroller does crazy things 
> file immediately a PR.
>
Only one minor point on this.. in 4.0, we really either need our 
unrolled code, or a better loop optimiser unless we want to take a 40% 
speed hit on std::find... so if we remove it and they can't get the loop 
optimiser fixed, either the current version or (I'd perfer, but won't 
force) the new version I originally posted should go back in.

Chris