__builtin_sub_overflow   36 include/linux/compiler-clang.h     __has_builtin(__builtin_sub_overflow)
__builtin_sub_overflow   70 include/linux/overflow.h 	__builtin_sub_overflow(__a, __b, __d);	\
__builtin_sub_overflow   64 tools/include/linux/overflow.h 	__builtin_sub_overflow(__a, __b, __d);	\