On Fri, 2013-04-19 at 13:43 -0700, Gary Hade wrote: > The above > "__field( u32, status )" > gets expanded to > "ret = trace_define_field(event_call, "u32", "status", __builtin_offsetof(typeof(field),status), sizeof(field.status), (((u32)(-1)) < (u32)0), FILTER_OTHER); if (ret) return ret;" > > The warning is triggered by: > "(((u32)(-1)) < (u32)0)" > which was put there by is_signed_type. > > It appears that is_signed_type is simply taking advantage of the same > action that the compiler is warning about to perform it's function. Yeah, that's the point of the macro. > > Not sure how to make is_signed_type warningless although > it does create a significant amount of noise during a full > `make W=1` kernel build. With 3.9-rc7 it appears to be > responsible for 1401 of 1476 occurrences of "warning: comparison > of unsigned expression < 0 is always false". Since it is complaining about being less than zero, I just checked, the following also works. #define is_signed_type(type) ((type)-1 < (type)1) And doesn't give the warning. I'll go make a patch. Thanks! -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
