Re: [PATCH v5 1/2] lib/test_bitops: Add benchmark test for fns()

From: kernel test robot <lkp@intel.com>
To: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev
Subject: Re: [PATCH v5 1/2] lib/test_bitops: Add benchmark test for fns()
Date: Fri, 3 May 2024 08:49:00 +0800	[thread overview]
Message-ID: <202405030808.UsoMKFNP-lkp@intel.com> (raw)
In-Reply-To: <20240502092443.6845-2-visitorckw@gmail.com>

Hi Kuan-Wei,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.9-rc6 next-20240502]
[cannot apply to akpm-mm/mm-everything akpm-mm/mm-nonmm-unstable]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Kuan-Wei-Chiu/lib-test_bitops-Add-benchmark-test-for-fns/20240502-172638
base:   linus/master
patch link:    https://lore.kernel.org/r/20240502092443.6845-2-visitorckw%40gmail.com
patch subject: [PATCH v5 1/2] lib/test_bitops: Add benchmark test for fns()
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20240503/202405030808.UsoMKFNP-lkp@intel.com/config)
compiler: clang version 18.1.4 (https://github.com/llvm/llvm-project e6c3289804a67ea0bb6a86fadbe454dd93b8d855)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240503/202405030808.UsoMKFNP-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/202405030808.UsoMKFNP-lkp@intel.com/

All errors (new ones prefixed by >>):

>> lib/test_bitops.c:56:39: error: variable 'tmp' set but not used [-Werror,-Wunused-but-set-variable]
      56 |         static volatile __used unsigned long tmp __initdata;
         |                                              ^
   1 error generated.

vim +/tmp +56 lib/test_bitops.c

    52	
    53	static int __init test_fns(void)
    54	{
    55		static unsigned long buf[10000] __initdata;
  > 56		static volatile __used unsigned long tmp __initdata;
    57		unsigned int i, n;
    58		ktime_t time;
    59	
    60		get_random_bytes(buf, sizeof(buf));
    61		time = ktime_get();
    62	
    63		for (n = 0; n < BITS_PER_LONG; n++)
    64			for (i = 0; i < 10000; i++)
    65				tmp = fns(buf[i], n);
    66	
    67		time = ktime_get() - time;
    68		pr_err("fns:  %18llu ns\n", time);
    69	
    70		return 0;
    71	}
    72	

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