Optimising std::find on x86 and PPC

[Paolo Carlini]

Chris Jefferson wrote:

> I suspect if it could unroll this by itself, then it would deal with 
> the processor-specific fixes itself.

Right. That's the whole point of my message and that's why, in my 
opinion, this *is*, fundamentally, a loop unrolling issue.

Ok, I'll try to check whether this is a know issue, already present in 
Bugzilla and if not file an appropriate PR.

Thanks,
Paolo.