On Fri, Jan 31, 2025 at 2:12 PM kernel test robot <lkp@xxxxxxxxx> 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@xxxxxxxxx/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@xxxxxxxxx/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@xxxxxxxxx> > | Closes: https://lore.kernel.org/oe-kbuild-all/202501312159.l6jNRaYy-lkp@xxxxxxxxx/ > > 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
