https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89284
Bug ID: 89284 Summary: gcc -fsanitize=undefined inhibits -Wuninitialized Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: jg at jguk dot org Target Milestone: --- Created attachment 45655 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45655&action=edit test case Hello Sanitzer team referred me back to here https://github.com/google/sanitizers/issues/1045#issuecomment-462197191 test case attached. Is this due to gcc? $ gcc-8 -Wall -fsanitize=undefined,address -o undef undef.c undef.c: In function ‘main’: undef.c:11:13: warning: unused variable ‘b’ [-Wunused-variable] t_t b = a; ^ jonny@asus:~/code/undef_t$ gcc-8 -Wall -fsanitize=address -o undef undef.c undef.c: In function ‘main’: undef.c:11:13: warning: unused variable ‘b’ [-Wunused-variable] t_t b = a; ^ undef.c:9:15: warning: ‘a.unset.hello’ is used uninitialized in this function [-Wuninitialized] if(a.unset.hello) ~~~~~~~^~~~~~ undef.c:11:13: warning: ‘a’ may be used uninitialized in this function [-Wmaybe-uninitialized] t_t b = a; ^ jonny@asus:~/code/undef_t$