Hi Alexander,
FYI, the error/warning still remains.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: a92b7d26c743b9dc06d520f863d624e94978a1d9
commit: dc34d5036692c614eef23c1130ee42a201c316bf lib: test_bitmap: add compile-time optimization/evaluations assertions
date: 12 months ago
config: x86_64-buildonly-randconfig-r003-20230624 (https://download.01.org/0day-ci/archive/20230625/[email protected]/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce: (https://download.01.org/0day-ci/archive/20230625/[email protected]/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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
>> lib/test_bitmap.c:920:2: error: call to __compiletime_assert_372 declared with 'error' attribute: BUILD_BUG_ON failed: !__builtin_constant_p(res)
BUILD_BUG_ON(!__builtin_constant_p(res));
^
include/linux/build_bug.h:50:2: note: expanded from macro 'BUILD_BUG_ON'
BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
^
include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON_MSG'
#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
^
include/linux/compiler_types.h:352:2: note: expanded from macro 'compiletime_assert'
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
include/linux/compiler_types.h:340:2: note: expanded from macro '_compiletime_assert'
__compiletime_assert(condition, msg, prefix, suffix)
^
include/linux/compiler_types.h:333:4: note: expanded from macro '__compiletime_assert'
prefix ## suffix(); \
^
<scratch space>:295:1: note: expanded from here
__compiletime_assert_372
^
1 error generated.
vim +/error +920 lib/test_bitmap.c
871
872 static void __init test_bitmap_const_eval(void)
873 {
874 DECLARE_BITMAP(bitmap, BITS_PER_LONG);
875 unsigned long initvar = BIT(2);
876 unsigned long bitopvar = 0;
877 unsigned long var = 0;
878 int res;
879
880 /*
881 * Compilers must be able to optimize all of those to compile-time
882 * constants on any supported optimization level (-O2, -Os) and any
883 * architecture. Otherwise, trigger a build bug.
884 * The whole function gets optimized out then, there's nothing to do
885 * in runtime.
886 */
887
888 /*
889 * Equals to `unsigned long bitmap[1] = { GENMASK(6, 5), }`.
890 * Clang on s390 optimizes bitops at compile-time as intended, but at
891 * the same time stops treating @bitmap and @bitopvar as compile-time
892 * constants after regular test_bit() is executed, thus triggering the
893 * build bugs below. So, call const_test_bit() there directly until
894 * the compiler is fixed.
895 */
896 bitmap_clear(bitmap, 0, BITS_PER_LONG);
897 #if defined(__s390__) && defined(__clang__)
898 if (!const_test_bit(7, bitmap))
899 #else
900 if (!test_bit(7, bitmap))
901 #endif
902 bitmap_set(bitmap, 5, 2);
903
904 /* Equals to `unsigned long bitopvar = BIT(20)` */
905 __change_bit(31, &bitopvar);
906 bitmap_shift_right(&bitopvar, &bitopvar, 11, BITS_PER_LONG);
907
908 /* Equals to `unsigned long var = BIT(25)` */
909 var |= BIT(25);
910 if (var & BIT(0))
911 var ^= GENMASK(9, 6);
912
913 /* __const_hweight<32|64>(GENMASK(6, 5)) == 2 */
914 res = bitmap_weight(bitmap, 20);
915 BUILD_BUG_ON(!__builtin_constant_p(res));
916 BUILD_BUG_ON(res != 2);
917
918 /* !(BIT(31) & BIT(18)) == 1 */
919 res = !test_bit(18, &bitopvar);
> 920 BUILD_BUG_ON(!__builtin_constant_p(res));
921 BUILD_BUG_ON(!res);
922
923 /* BIT(2) & GENMASK(14, 8) == 0 */
924 res = initvar & GENMASK(14, 8);
925 BUILD_BUG_ON(!__builtin_constant_p(res));
926 BUILD_BUG_ON(res);
927
928 /* ~BIT(25) */
929 BUILD_BUG_ON(!__builtin_constant_p(~var));
930 BUILD_BUG_ON(~var != ~BIT(25));
931 }
932
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Sun, Jun 25, 2023 at 05:12:36AM +0800, kernel test robot wrote:
> Hi Alexander,
>
> FYI, the error/warning still remains.
Alexander, do you have anything to present to fix this? Or is your plan to send
something after v6.5-rc1?
--
With Best Regards,
Andy Shevchenko
From: Andy Shevchenko <[email protected]>
Date: Mon, 26 Jun 2023 11:32:51 +0300
> On Sun, Jun 25, 2023 at 05:12:36AM +0800, kernel test robot wrote:
>> Hi Alexander,
>>
>> FYI, the error/warning still remains.
>
> Alexander, do you have anything to present to fix this? Or is your plan to send
> something after v6.5-rc1?
Hi,
I was waiting for an email from Nick (or some further update of the
GitHub issue page) to clarify whether the compiler should be fixed or I
should work around this in the code. If the latter, I could send a fix
this week, so that it could even hit the bitmap pull request.
Thanks,
Olek
On Mon, Jun 26, 2023 at 01:57:46PM +0200, Alexander Lobakin wrote:
> From: Andy Shevchenko <[email protected]>
> Date: Mon, 26 Jun 2023 11:32:51 +0300
> > On Sun, Jun 25, 2023 at 05:12:36AM +0800, kernel test robot wrote:
> >> Hi Alexander,
> >>
> >> FYI, the error/warning still remains.
> >
> > Alexander, do you have anything to present to fix this? Or is your plan to send
> > something after v6.5-rc1?
>
> I was waiting for an email from Nick (or some further update of the
> GitHub issue page) to clarify whether the compiler should be fixed or I
> should work around this in the code.
Okay, got it! Maybe you can ping him?
> If the latter, I could send a fix
> this week, so that it could even hit the bitmap pull request.
It could hit a PR after v6.5-rc1 (Linus expects the following: a) the PR
to be send in the _first_ week of merge window with rare exceptions, and
b) the commits in PR has to be sit in Linux Next for a while, usually
a couple of weeks).
--
With Best Regards,
Andy Shevchenko