https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106171
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> --- And -O1 -Wall warns: pr106171.c: In function ‘c’: pr106171.c:10:15: warning: ‘e[0]’ is used uninitialized [-Wuninitialized] 10 | return e[0]; | ~^~~ pr106171.c:6:9: note: ‘e’ declared here 6 | int e[2]; | ^