Re: [PATCH 3/5] testsuite/smokey/vxworktests: Fix compile error seen with gcc 16

On 13.05.26 15:55, Florian Bezdeka wrote:
> On Wed, 2026-05-13 at 15:52 +0200, Jan Kiszka wrote:
>> On 13.05.26 14:50, Florian Bezdeka wrote:
>>> Fixes the following error:
>>>
>>> task-2.c: In function ‘backgroundTask’:
>>> task-2.c:26:42: error: variable ‘count’ set but not used [-Werror=unused-but-set-variable=]
>>>    26 |         unsigned int safety = 100000000, count = 0;
>>>       |                                          ^~~~~
>>> cc1: all warnings being treated as errors
>>>
>>> Signed-off-by: Florian Bezdeka <[email protected]>
>>> ---
>>>  testsuite/smokey/vxworkstests/task-2.c | 5 ++---
>>>  1 file changed, 2 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/testsuite/smokey/vxworkstests/task-2.c b/testsuite/smokey/vxworkstests/task-2.c
>>> index 0cbb9e18a13383418c4360241ef244b8a24da975..ed3e31806baad930bb30edc53d2dc6b6e51d6277 100644
>>> --- a/testsuite/smokey/vxworkstests/task-2.c
>>> +++ b/testsuite/smokey/vxworkstests/task-2.c
>>> @@ -23,7 +23,7 @@ static SEM_ID sem_id, fdone_sem_id;
>>>  
>>>  static void backgroundTask(long arg, ...)
>>>  {
>>> -	unsigned int safety = 100000000, count = 0;
>>> +	unsigned int safety = 100000000;
>>>  	int ret;
>>>  
>>>  	traceobj_enter(&trobj);
>>> @@ -35,8 +35,7 @@ static void backgroundTask(long arg, ...)
>>>  
>>>  	traceobj_mark(&trobj, 2);
>>>  
>>> -	while (--safety > 0)
>>> -		count++;
>>> +	while (--safety > 0) {}
>>
>> This first of all increases the risk of getting optimized out. I suspect
>> this is intended to generate some load, and that needs to be preserved.
>> We should likely do that via a busy loop which spins for a number of
>> microseconds.
>>
> 
> I compared the generated code, where only the increment was missing. Let
> me double check that the optimization level was > 0.

Neither the new nor the current versions are safe here, specifically
regarding timing.

Jan

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