http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52839
Alan Modra <amodra at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|4.7.1 |--- --- Comment #22 from Alan Modra <amodra at gmail dot com> 2012-04-10 23:53:16 UTC --- Regarding the ABI change, would I be correct to say that the ABI was broken for powerpc by 2012-02-10 Benjamin Kosnik <b...@redhat.com> Jonathan Wakely <jwakely....@gmail.com> since that particular patch introduced the dependency on having long long atomics? If I understand correctly, before that change code would use sync builtins on powerpc throughout. So code compiled before that date won't behave correctly using a current libstdc++.so, which now uses mutexes. I'm not trying to apportion blame, just pointing out that making libstdc++ use atomics on powerpc *fixes* an ABI breakage for the great majority of cases.