https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84816
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Dmitry Lesnikov from comment #4) > (In reply to Andrew Pinski from comment #1) > > signed overflow is undefined behavior at runtime. > > for(int i=0; i<10; i++) > > this loop is correct. But there is an overflow with the variable a when i is 6.