Updated patch for std::list: Performance and memory usage improvements.

[Gabriel Dos Reis]

Gawain Bolton <gbolton@free.fr> writes:

| Gabriel Dos Reis wrote:
| 
| >Gawain Bolton <gbolton@free.fr> writes:
| >
| >| Once again this is an updated patch (see attached), this time for
| >| std::list.  The original patch was posted a while back:
| > | |     http://gcc.gnu.org/ml/libstdc++/2003-02/msg00179.html
| > | | Here's the suggested change log entry:
| > | | 2003-07-05  Gawain Bolton  <gp.bolton@computer.org>
| > | |     * include/bits/stl_list.h: Performance and memory usage
| >|       improvements.
| >|     * include/bits/list.tcc: Likewise.
| >
| >
| >Please, could you  name the functions/classes/data you're touching in
| >your patches?  The above entry isn't really helpful :-(
| >
| The patch changed the std::list class.  The main change is to the
| behaviour of the constructor and destructor as the list header node is
| no longer dynamically allocated/de-allocated.

Those need to be mentioned in the ChangeLog entry -- that helps when
doing archeology.  See the reste of the  ChangeLog file.

| This improves
| performance and saves memory.
| 
| >
| >Do you have any measurements regarding your improvements?
| >
| >
| Yes, using the attached performance test program here are some numbers
| tested on i686-pc-linux-gnu.

Thanks, those pieces of information worth mentioning when sending the
patch -- the patch looks like more uglication and one might wonder
whether the obfuscation buys us anything.

Thanks.