At the company where I work, we have a large program using Boost Python (1.54). We do our product builds for RHEL 5 and recently started building using gcc 4.8 from RedHat devtoolset 2 for performance. This works well, except for one system where it would deterministically crash. I traced it to an old version of libgcc, and specifically this patch, which RedHat applied to its 5.5 release in 2009: <http://sophie.aero.jussieu.fr/distrib/Scientific%20Linux/5x/x86_64/by-pkgid/b5e52bbfb4bb11a6cbed452927fba979/files/118>. I built libgcc myself with and without the patch, with the program crashing reliably without the patch, and no crash with the patch applied. Unfortunately, gdb does not show a meaningful stack trace, at least not the old version from RHEL 5.
When trying to find out a bit more about the patch, I was rather surprised to see that (1) it is not applied to the mainline gcc code and (2) it still applies cleanly. Since I don't have a good stack trace, I cannot even try to build a suitable reproducer at the moment. Is there a good reason for not having it in mainline gcc? I suppose it got lost or forgotten somehow, and that it would be good to have it applied.
