__has_builtin      34 include/linux/compiler-clang.h #if __has_builtin(__builtin_mul_overflow) && \
__has_builtin      35 include/linux/compiler-clang.h     __has_builtin(__builtin_add_overflow) && \
__has_builtin      36 include/linux/compiler-clang.h     __has_builtin(__builtin_sub_overflow)