https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79430
--- Comment #45 from Jürgen Reuter <juergen.reuter at desy dot de> --- Looking into my backups, it seems that the revision 241975 from Nov 8, 2016 was still working without the `volatile` hack. Then I upgraded in early February to revision 245197 where the problem is already present. Unfortunately I cannot narrow it down any further. Any smaller test case is incredibly difficult to produce for us.
