Patch: improving performance of basic_string modification functions

[Jason Merrill]

>>>>> "Benjamin" == Benjamin Kosnik <bkoz@redhat.com> writes:

> I would prefer if the testsuite was augmented to deal with basic 
> performance analysis issues before too much stuff like this gets checked in.

> Any thoughts on how to do this?

Something like the stepanov abstraction penalty test would make sense, to
at least verify that we conform to the complexity requirements of the
standard; i.e. time adding one character to a string, then time adding a
lot of characters one at a time and make sure that we take no more than
linear time.

Jason