On Fri, Jan 31, 2025 at 1:23 PM Uros Bizjak <ubizjak@xxxxxxxxx> wrote: > > 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?! 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
