Re: [arm-perf:for-next/perf 6/8] drivers/perf/arm-ni.c:433:13: warning: operator '?:' has lower precedence than '+'; '+' will be evaluated first

[Robin Murphy <robin.murphy@arm.com>]

On 2025-11-04 12:35 pm, Will Deacon wrote:
> On Tue, Nov 04, 2025 at 05:43:40PM +0800, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git for-next/perf
>> head:   989b40b7578a2be7b0388522d33d751b257d59d9
>> commit: 8fa08f8835e57e1fd5e2994c9cf76c84dadc1235 [6/8] perf/arm-ni: Add NoC S3 support
>> config: sparc64-randconfig-002-20251104 (https://download.01.org/0day-ci/archive/20251104/202511041749.ok8zDP6u-lkp@intel.com/config)
>> compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project d2625a438020ad35330cda29c3def102c1687b1b)
>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251104/202511041749.ok8zDP6u-lkp@intel.com/reproduce)
>>
>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
>> the same patch/commit), kindly add following tags
>> | Reported-by: kernel test robot <lkp@intel.com>
>> | Closes: https://lore.kernel.org/oe-kbuild-all/202511041749.ok8zDP6u-lkp@intel.com/
>>
>> All warnings (new ones prefixed by >>):
>>
>>>> drivers/perf/arm-ni.c:433:13: warning: operator '?:' has lower precedence than '+'; '+' will be evaluated first [-Wparentheses]
>>       432 |                 hw->event_base = (unsigned long)cd->pmu_base +
>>           |                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>       433 |                                  is_7xx ? NI700_PMCCNTR_L : NI_PMCCNTR_L;
>>           |                                  ~~~~~~ ^
>>     drivers/perf/arm-ni.c:433:13: note: place parentheses around the '+' expression to silence this warning
>>       432 |                 hw->event_base = (unsigned long)cd->pmu_base +
>>           |                                  (
>>       433 |                                  is_7xx ? NI700_PMCCNTR_L : NI_PMCCNTR_L;
>>           |                                         ^
>>           |                                        )
> 
> Hrm. Doesn't that mean this is completely broken or am I misreading the
> report?

Bah, my arm64 W=1 build (which I did do in the hope of catching any such 
sillies...) fails to flag that :(

Truth is this is a fresh refactoring of the mess I originally wrote that 
got tested by someone else 18 months ago, and I don't have any hardware 
to functionally test it myself. Feel free to drop it and I'll send a 
complete v2, or I can do an incremental fix if you prefer (I already 
realised I could have streamlined the version check to a one-off in 
event_init as well.)

Cheers,
Robin.