[Patch] Batch of basic_string correctness and performance work

[Paolo Carlini]

Nathan Myers wrote:

>Thank you, Paolo.  This makes me feel better, too.  Few enough of
>us have Opterons, so far.  Among those of us who do, few are yet 
>inclined to complain about how long they take to get through their 
>workload. :-)
>  
>
Yes :-)

Seriously, I'm becoming every day more nervous because of this problem, 
it's not just about inlining more or less: too often a "straightforward" 
improvement on x86_64 gives weird surprises on x86 and we cannot really 
optimize the code for both.

Anyway, let's move ahead.

Paolo.