Re: [PATCH v2 1/5] lib: add bitrev8x4()

From: kbuild test robot
Date: Fri Oct 28 2016 - 14:52:07 EST


Hi Joshua,

[auto build test WARNING on linus/master]
[also build test WARNING on v4.9-rc2 next-20161028]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
[Suggest to use git(>=2.9.0) format-patch --base=<commit> (or --base=auto for convenience) to record what (public, well-known) commit your patch series was built on]
[Check https://git-scm.com/docs/git-format-patch for more information]

url: https://github.com/0day-ci/linux/commits/Joshua-Clayton/lib-add-bitrev8x4/20161029-012535
config: arm-s5pv210_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=arm

All warnings (new ones prefixed by >>):

In file included from include/linux/bitrev.h:7:0,
from include/linux/crc32.h:9,
from lib/crc32.c:29:
arch/arm/include/asm/bitrev.h: In function '__arch_bitrev8x4':
>> arch/arm/include/asm/bitrev.h:23:1: warning: no return statement in function returning non-void [-Wreturn-type]
}
^

vim +23 arch/arm/include/asm/bitrev.h

7 return x;
8 }
9
10 static __always_inline __attribute_const__ u16 __arch_bitrev16(u16 x)
11 {
12 return __arch_bitrev32((u32)x) >> 16;
13 }
14
15 static __always_inline __attribute_const__ u8 __arch_bitrev8(u8 x)
16 {
17 return __arch_bitrev32((u32)x) >> 24;
18 }
19
20 static __always_inline __attribute_const__ u32 __arch_bitrev8x4(u32 x)
21 {
22 __asm__ ("rbit %0, %1; rev %0, %0" : "=r" (x) : "r" (x));
> 23 }
24
25 #endif

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