arch/mips/boot/compressed/../../../../lib/ashldi3.c:9:19: warning: no previous prototype for function '__ashldi3'

[kernel test robot <lkp@intel.com>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   278218f6778bc7d6f8b67199446c56cec7ebb841
commit: f78b25ee922ef6faf59a258af1b9388ca894cfd9 mips: decompressor: do not copy source files while building
date:   7 weeks ago
config: mips-loongson1c_defconfig (https://download.01.org/0day-ci/archive/20220102/202201020552.pSlQpO1b-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c054402170cd8466683a20385befc0523aba3359)
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/?id=f78b25ee922ef6faf59a258af1b9388ca894cfd9
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout f78b25ee922ef6faf59a258af1b9388ca894cfd9
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from arch/mips/boot/compressed/ashldi3.c:2:
>> arch/mips/boot/compressed/../../../../lib/ashldi3.c:9:19: warning: no previous prototype for function '__ashldi3' [-Wmissing-prototypes]
   long long notrace __ashldi3(long long u, word_type b)
                     ^
   arch/mips/boot/compressed/../../../../lib/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.


vim +/__ashldi3 +9 arch/mips/boot/compressed/../../../../lib/ashldi3.c

b35cd9884fa5d8 Palmer Dabbelt 2017-05-23  8  
b35cd9884fa5d8 Palmer Dabbelt 2017-05-23 @9  long long notrace __ashldi3(long long u, word_type b)

:::::: The code at line 9 was first introduced by commit
:::::: b35cd9884fa5d81c9d5e7f57c9d03264ae2bd835 lib: Add shared copies of some GCC library routines

:::::: TO: Palmer Dabbelt <palmer@dabbelt.com>
:::::: CC: Palmer Dabbelt <palmer@dabbelt.com>

---
0-DAY CI Kernel Test Service, Intel Corporation
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