patch applied (packages/containers): Settle performance issues inIntMap and IntSet.

[Claus Reinke]

> Fri Oct 29 16:16:53 PDT 2010  Milan Straka <fox at ucw.cz>
>  * Settle performance issues in IntMap and IntSet.
>  
>  The worker-wrapper transformation is removed from
>  all functions but lookup and member. This is the
>  only place where it causes benefits -- a 10% to
>  15% speedup. It increases memory allocation
>  slightly (0-5%), but the effect on GHC is really
>  minor.

Just curious: those tests do test propagation of strictness
in function parameters of higher-order functions, yes? And
there was no benefit in those cases? Wouldn't that imply
that List foldl would also no longer need the worker-wrapper
split? It would be a substantial, so far undocumented,
 improvement in GHC's optimization abilities.
 
Claus