https://gcc.gnu.org/bugzilla/show_bug.cgi?id=28901
--- Comment #19 from Chen Gang <gang.chen.5i5j at gmail dot com> --- I build linux kernel with allyesconfig under x86_64 for linux-next tree 20160122. I can find some related cases for BUG28901 (but they are not quite much), one case is below: CC drivers/acpi/sbshc.o In file included from drivers/acpi/sbshc.c:17:0: drivers/acpi/sbshc.h:17:17: warning: ‘SMBUS_PEC’ defined but not used [-Wunused-const-variable] static const u8 SMBUS_PEC = 0x80; ^~~~~~~~~ For me, I dislike -Wno-unused-const-variable option, the reason is "when C programmers use static const int variable, in most cases, they want to use them instead of #define". So for me, -Wunused-variable need skip static const int variable warning. If anyone wants to warn about it, they can add additional option (e.g. -Wunused-const-int-variable) to let C compiler report warning for it. Thanks.