https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69126
--- Comment #23 from Manuel López-Ibáñez <manu at gcc dot gnu.org> --- (In reply to Stephan Bergmann from comment #18) > (Also, the problem > only happens with -O or higher.) That is weird. If you use "GCC diagnostic warning" instead of "ignored", you should be able to see some changes in locations between -O0 and -O1 and before/after the bug appeared, don't you?