basic_string patch

[Martin v. Loewis]

> eventually I have re-diffed the patch vs today's mainline. I'm still
> convinced that the original one, that on libstdc++, is perfectly
> correct, it's just that sometimes I use tabs instead of plain spaces
> and viceversa and...

The main problem is that the patch has seen HTML markup in the
archives. Undoing this is not trivial, especially as line breaks were
inserted in the wrong spots.

> Anyway, please let us know your opinion. As you may see from the
> benchmarks I have posted the effect of the exponential allocation
> (vs the improvements already in mainline) should be particularly
> noticeable when out-of-cache and/or for long concateaned strings.

The improvements in the mainline are indeed significant. Your patch
adds a slight speed-up on top of the mainline. It still doesn't
achieve the 2.95 performance; for my test case, gcc 3.1 takes twice as
much time as 2.95 (on Pentium III).

Regards,
Martin