Re: [PATCH v2] tracing: Make is_signed_type() compatible with sparse

[Bart Van Assche <bvanassche@acm.org>]

On 9/1/26 2:29 PM, David Laight wrote:
> On Tue, 1 Sep 2026 11:05:18 -0700
> Bart Van Assche <bvanassche@acm.org> wrote:
> 
>> On 9/1/26 1:20 AM, David Laight wrote:
>>> I suspect you need to change the TRACE_EVENT() calls to remove the
>>> __bitwise marker.
>>
>> How to remove the __bitwise marker? Removing the __bitwise marker is not
>> supported by sparse, isn't it?
> 
> Wont (__force u32)u32_bitwise_var remove it - you just have to know the
> type.

Yes, removing __bitwise is possible if the underlying type is known. In
the context of the is_signed_type() macro, the underlying type is not
passed as an argument to that macro.

The implementation in sparse of __type_unqual__ does not remove
__attribute__((bitwise)) as far as I know. __typeof_unqual__ only strips
C type qualifiers: const, volatile, restrict, and _Atomic.

The only generic way I know of to remove the __bitwise marker is by
using _Generic(). But that approach has been rejected by Linus.

Bart.