basic_string atomicity

[Jonathan Wakely]

On 6 January 2012 14:34, David Edelsohn wrote:
>
> Unfortunately the changes to __sync_fetch_and_add because of the C++11
> memory model changes to GCC ALREADY HAVE CAUSED A REGRESSION that
> affects libstdc++.  G++ now produces worse code, at least for
> architectures that can make a distinction among the various memory
> models.

We probably want to CC Andrew and Aldy here, as I can't speak for the
other libstdc++ maintainers but personally I usually try not to touch
the existing code using atomic ops unless they're broken, and even
then I prefer to ask an expert!

Andrew, Aldy, please see
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51766 for the sync vs
lwsync change, and the thread starting at
http://gcc.gnu.org/ml/libstdc++/2012-01/msg00037.html