https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83433
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- The docs don't indicate that to me. The option warns about checking if the result of abs(x) is non-negative, which is true except for the undefined case of abs(INT_MIN), it doesn't warn about the call to abs(INT_MIN) itself. Also note that your wandbox example doesn't enable -fstrict-overflow, so the warning option is ignored. "This option is only active when -fstrict-overflow is active." (But there's still no warning with -fstrict-overflow).