linux-kernel - Re: drivers/iio/accel/adxl372.c:949:3: warning: converting the result of '<<' to a boolean always evaluates to true

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Date:   Thu, 14 Jan 2021 11:24:25 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     kernel test robot <lkp@...el.com>
Cc:     Stefan Popa <stefan.popa@...log.com>, kbuild-all@...ts.01.org,
        clang-built-linux@...glegroups.com, linux-kernel@...r.kernel.org,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Alexandru Tachici <alexandru.tachici@...log.com>
Subject: Re: drivers/iio/accel/adxl372.c:949:3: warning: converting the
 result of '<<' to a boolean always evaluates to true

On Fri, Jan 15, 2021 at 02:19:41AM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   65f0d2414b7079556fbbcc070b3d1c9f9587606d
> commit: b0fc6783d4ae58f796fb183c40dbc7fa3199d51d iio: accel: adxl372: Add support for FIFO peak mode
> date:   4 months ago
> config: mips-randconfig-r026-20210114 (attached as .config)
> compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 68ff52ffead2ba25cca442778ab19286000daad7)
> 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=b0fc6783d4ae58f796fb183c40dbc7fa3199d51d
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout b0fc6783d4ae58f796fb183c40dbc7fa3199d51d
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@...el.com>
> 
> All warnings (new ones prefixed by >>):
> 
>    In file included from include/linux/interrupt.h:8:
>    In file included from include/linux/cpumask.h:13:
>    In file included from include/linux/atomic.h:7:
>    arch/mips/include/asm/atomic.h:52:1: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare]
>    arch/mips/include/asm/atomic.h:45:9: note: expanded from macro 'ATOMIC_OPS'
>            return xchg(&v->counter, n);                                    \
>                   ^
>    arch/mips/include/asm/cmpxchg.h:102:7: note: expanded from macro 'xchg'
>            if (!__SYNC_loongson3_war)                                      \
>                 ^
>    arch/mips/include/asm/sync.h:147:34: note: expanded from macro '__SYNC_loongson3_war'
>    # define __SYNC_loongson3_war   (1 << 31)
>                                       ^

Sorry for the noise, I have sent a patch to fix this:

https://lore.kernel.org/lkml/20210114173416.738455-1-natechancellor@gmail.com/

Cheers,
Nathan