https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67828
--- Comment #5 from Zhendong Su <su at cs dot ucdavis.edu> --- > This testcase invokes undefined behavior because of the overflow on the > iterator, ... Just a quick comment that the testcase doesn't have undefined behaviors. As the variable c is of type short, there shouldn't be signed overflow --- the operations will be performed on its signed extended integer value and then truncated back to a short. Thanks for looking into and fixing the issue.