* [akpm-mm:mm-nonmm-unstable 52/52] lib/bch.c:317:undefined reference to `__paritydi2'
@ 2025-01-31 13:12 kernel test robot
2025-01-31 13:19 ` Uros Bizjak
0 siblings, 1 reply; 4+ messages in thread
From: kernel test robot @ 2025-01-31 13:12 UTC (permalink / raw)
To: Uros Bizjak; +Cc: oe-kbuild-all, Andrew Morton, Linux Memory Management List
tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-nonmm-unstable
head: 1b9f78ccbffefb107cd92e20cfccd03ff2fa9d0e
commit: 1b9f78ccbffefb107cd92e20cfccd03ff2fa9d0e [52/52] lib/bch.c: use __builtin_parity() when available
config: arm64-randconfig-002-20250131 (https://download.01.org/0day-ci/archive/20250131/202501312159.l6jNRaYy-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250131/202501312159.l6jNRaYy-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/202501312159.l6jNRaYy-lkp@intel.com/
All errors (new ones prefixed by >>):
aarch64-linux-ld: lib/bch.o: in function `parity':
>> lib/bch.c:317:(.text+0x10e8): undefined reference to `__paritydi2'
>> lib/bch.c:317:(.text+0x10e8): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__paritydi2'
vim +317 lib/bch.c
313
314 static inline int parity(unsigned int x)
315 {
316 #if __has_builtin(__builtin_parity)
> 317 return __builtin_parity(x);
318 #else
319 /*
320 * public domain code snippet, lifted from
321 * http://www-graphics.stanford.edu/~seander/bithacks.html
322 */
323 x ^= x >> 1;
324 x ^= x >> 2;
325 x = (x & 0x11111111U) * 0x11111111U;
326 return (x >> 28) & 1;
327 #endif
328 }
329
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [akpm-mm:mm-nonmm-unstable 52/52] lib/bch.c:317:undefined reference to `__paritydi2'
2025-01-31 13:12 [akpm-mm:mm-nonmm-unstable 52/52] lib/bch.c:317:undefined reference to `__paritydi2' kernel test robot
@ 2025-01-31 13:19 ` Uros Bizjak
2025-01-31 14:34 ` Pedro Falcato
0 siblings, 1 reply; 4+ messages in thread
From: Uros Bizjak @ 2025-01-31 13:19 UTC (permalink / raw)
To: kernel test robot
Cc: oe-kbuild-all, Andrew Morton, Linux Memory Management List
On Fri, Jan 31, 2025 at 2:12 PM kernel test robot <lkp@intel.com> wrote:
>
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-nonmm-unstable
> head: 1b9f78ccbffefb107cd92e20cfccd03ff2fa9d0e
> commit: 1b9f78ccbffefb107cd92e20cfccd03ff2fa9d0e [52/52] lib/bch.c: use __builtin_parity() when available
> config: arm64-randconfig-002-20250131 (https://download.01.org/0day-ci/archive/20250131/202501312159.l6jNRaYy-lkp@intel.com/config)
> compiler: aarch64-linux-gcc (GCC) 14.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250131/202501312159.l6jNRaYy-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/202501312159.l6jNRaYy-lkp@intel.com/
>
> All errors (new ones prefixed by >>):
>
> aarch64-linux-ld: lib/bch.o: in function `parity':
> >> lib/bch.c:317:(.text+0x10e8): undefined reference to `__paritydi2'
> >> lib/bch.c:317:(.text+0x10e8): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__paritydi2'
This config for some reason generates a call to the library function.
But I have tested this with a crosscompiler:
fmov s31, w0
cnt v31.8b, v31.8b
addv b31, v31.8b
fmov w0, s31
and w0, w0, 1
ret
It looks that __has_builtin() does not mean that there will be no call
to a library function?!
Uros.
>
> vim +317 lib/bch.c
>
> 313
> 314 static inline int parity(unsigned int x)
> 315 {
> 316 #if __has_builtin(__builtin_parity)
> > 317 return __builtin_parity(x);
> 318 #else
> 319 /*
> 320 * public domain code snippet, lifted from
> 321 * http://www-graphics.stanford.edu/~seander/bithacks.html
> 322 */
> 323 x ^= x >> 1;
> 324 x ^= x >> 2;
> 325 x = (x & 0x11111111U) * 0x11111111U;
> 326 return (x >> 28) & 1;
> 327 #endif
> 328 }
> 329
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [akpm-mm:mm-nonmm-unstable 52/52] lib/bch.c:317:undefined reference to `__paritydi2'
2025-01-31 13:19 ` Uros Bizjak
@ 2025-01-31 14:34 ` Pedro Falcato
2025-01-31 15:42 ` Uros Bizjak
0 siblings, 1 reply; 4+ messages in thread
From: Pedro Falcato @ 2025-01-31 14:34 UTC (permalink / raw)
To: Uros Bizjak
Cc: kernel test robot, oe-kbuild-all, Andrew Morton,
Linux Memory Management List
On Fri, Jan 31, 2025 at 1:23 PM Uros Bizjak <ubizjak@gmail.com> wrote:
>
> On Fri, Jan 31, 2025 at 2:12 PM kernel test robot <lkp@intel.com> wrote:
> >
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-nonmm-unstable
> > head: 1b9f78ccbffefb107cd92e20cfccd03ff2fa9d0e
> > commit: 1b9f78ccbffefb107cd92e20cfccd03ff2fa9d0e [52/52] lib/bch.c: use __builtin_parity() when available
> > config: arm64-randconfig-002-20250131 (https://download.01.org/0day-ci/archive/20250131/202501312159.l6jNRaYy-lkp@intel.com/config)
> > compiler: aarch64-linux-gcc (GCC) 14.2.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250131/202501312159.l6jNRaYy-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/202501312159.l6jNRaYy-lkp@intel.com/
> >
> > All errors (new ones prefixed by >>):
> >
> > aarch64-linux-ld: lib/bch.o: in function `parity':
> > >> lib/bch.c:317:(.text+0x10e8): undefined reference to `__paritydi2'
> > >> lib/bch.c:317:(.text+0x10e8): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__paritydi2'
>
> This config for some reason generates a call to the library function.
> But I have tested this with a crosscompiler:
>
> fmov s31, w0
> cnt v31.8b, v31.8b
> addv b31, v31.8b
> fmov w0, s31
> and w0, w0, 1
> ret
>
> It looks that __has_builtin() does not mean that there will be no call
> to a library function?!
Yep, __builtin functions aren't strictly required to be inlined and
can generate a library call if the compiler so chooses (how often this
happens depends on the optimization level and architecture).
e.g: https://godbolt.org/z/zKPb9hbaM
--
Pedro
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [akpm-mm:mm-nonmm-unstable 52/52] lib/bch.c:317:undefined reference to `__paritydi2'
2025-01-31 14:34 ` Pedro Falcato
@ 2025-01-31 15:42 ` Uros Bizjak
0 siblings, 0 replies; 4+ messages in thread
From: Uros Bizjak @ 2025-01-31 15:42 UTC (permalink / raw)
To: Pedro Falcato
Cc: kernel test robot, oe-kbuild-all, Andrew Morton,
Linux Memory Management List
On Fri, Jan 31, 2025 at 3:34 PM Pedro Falcato <pedro.falcato@gmail.com> wrote:
>
> On Fri, Jan 31, 2025 at 1:23 PM Uros Bizjak <ubizjak@gmail.com> wrote:
> >
> > On Fri, Jan 31, 2025 at 2:12 PM kernel test robot <lkp@intel.com> wrote:
> > >
> > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-nonmm-unstable
> > > head: 1b9f78ccbffefb107cd92e20cfccd03ff2fa9d0e
> > > commit: 1b9f78ccbffefb107cd92e20cfccd03ff2fa9d0e [52/52] lib/bch.c: use __builtin_parity() when available
> > > config: arm64-randconfig-002-20250131 (https://download.01.org/0day-ci/archive/20250131/202501312159.l6jNRaYy-lkp@intel.com/config)
> > > compiler: aarch64-linux-gcc (GCC) 14.2.0
> > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250131/202501312159.l6jNRaYy-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/202501312159.l6jNRaYy-lkp@intel.com/
> > >
> > > All errors (new ones prefixed by >>):
> > >
> > > aarch64-linux-ld: lib/bch.o: in function `parity':
> > > >> lib/bch.c:317:(.text+0x10e8): undefined reference to `__paritydi2'
> > > >> lib/bch.c:317:(.text+0x10e8): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__paritydi2'
> >
> > This config for some reason generates a call to the library function.
> > But I have tested this with a crosscompiler:
> >
> > fmov s31, w0
> > cnt v31.8b, v31.8b
> > addv b31, v31.8b
> > fmov w0, s31
> > and w0, w0, 1
> > ret
> >
> > It looks that __has_builtin() does not mean that there will be no call
> > to a library function?!
>
> Yep, __builtin functions aren't strictly required to be inlined and
> can generate a library call if the compiler so chooses (how often this
> happens depends on the optimization level and architecture).
> e.g: https://godbolt.org/z/zKPb9hbaM
Thanks for the example!
I have to retract the patch.
Thanks,
Uros.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-01-31 13:12 [akpm-mm:mm-nonmm-unstable 52/52] lib/bch.c:317:undefined reference to `__paritydi2' kernel test robot
2025-01-31 13:19 ` Uros Bizjak
2025-01-31 14:34 ` Pedro Falcato
2025-01-31 15:42 ` Uros Bizjak
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