https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107908
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- If you used -ftrivial-auto-var-init=zero you would get the runtime error: /app/example.cpp:6:5: runtime error: load of null pointer of type 'int' With -ftrivial-auto-var-init=pattern you get: /app/example.cpp:6:5: runtime error: load of misaligned address 0xfefefefefefefefe for type 'int', which requires 4 byte alignment 0xfefefefefefefefe: note: pointer points here <memory cannot be printed> Which is also expected.