[gustavoars-linux:for-next/clang-fallthrough 1/1] warning: fallthrough annotation in unreachable code

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git for-next/clang-fallthrough
head:   58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
commit: 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00 [1/1] Revert "Revert "Makefile: Enable -Wimplicit-fallthrough for Clang""
config: hexagon-randconfig-r023-20210804 (attached as .config)
compiler: clang version 12.0.0
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
        # https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
        git remote add gustavoars-linux https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git
        git fetch --no-tags gustavoars-linux for-next/clang-fallthrough
        git checkout 58d0d2d2e7dc1b1a4997bb9c47d6cf428f2d3a00
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=hexagon 

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

All warnings (new ones prefixed by >>):

>> warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
>> warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough]
   2 warnings generated.

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0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

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