[Bug libstdc++/51798] [4.7 regression] libstdc++ atomicity performance regression due to __sync_fetch_and_add

[amacleod at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51798

--- Comment #12 from Andrew Macleod <amacleod at redhat dot com> 2012-01-26 13:57:56 UTC ---
(In reply to comment #11)
> What about the other files that use __sync_* in libstdc++?

I would change the bare minimum... Every change is a risk of some sort this
late n the game.   The only reason to consider this change was the unacceptable
performance regression on power which was reported.   If it hasn't been
reported, I'd leave it alone personally :-)

I hope to replace *all* __sync calls everywhere in the toolchain with __atomic
for 4.8. That way there is also time to evaluate the proper model for each one
and test it.