Hi Thomas, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: c06a2ba62fc401b7aaefd23f5d0bc06d2457ccc1 commit: 396c7d94c3bbe07ae00c9f694a5c731878843038 MIPS: alchemy: Fix build breakage, if TOUCHSCREEN_WM97XX is disabled date: 7 months ago config: mips-randconfig-r012-20210513 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project a0fed635fe1701470062495a6ffee1c608f3f1bc) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install mips cross compiling tool for clang build # apt-get install binutils-mips-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 396c7d94c3bbe07ae00c9f694a5c731878843038 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): long long notrace __ashldi3(long long u, word_type b) ^ arch/mips/boot/compressed/ashldi3.c:9:1: note: declare 'static' if the function is not intended to be used outside of this translation unit long long notrace __ashldi3(long long u, word_type b) ^ static 1 warning generated. -- unsigned int notrace __bswapsi2(unsigned int u) ^ arch/mips/boot/compressed/bswapsi.c:5:1: note: declare 'static' if the function is not intended to be used outside of this translation unit unsigned int notrace __bswapsi2(unsigned int u) ^ static 1 warning generated. -- void putc(char c) ^ arch/mips/boot/compressed/uart-alchemy.c:4:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void putc(char c) ^ static 1 warning generated. --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org