[linux-stable-rc:linux-5.15.y 6874/8723] arch/arm/lib/xor-neon.c:30:2: warning: This code requires at least version 4.6 of GCC

kernel test robot
2022-07-24T20:15:24Z

tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y
head: a9e2d8e52e1c0d87c0fa4f9d2d38e210aabed515
commit: e16cc79b0f916069de223bdb567fa0bc2ccd18a5 [6874/8723] lib/crypto: add prompts back to crypto libraries
config: arm-buildonly-randconfig-r006-20220724 (https://download.01.org/0day-ci/archive/20220725/202207250449.BYMZbIA2-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 12fbd2d377e396ad61bce56d71c98a1eb1bebfa9)
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 arm cross compiling tool for clang build
# apt-get install binutils-arm-linux-gnueabi
# https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=e16cc79b0f916069de223bdb567fa0bc2ccd18a5
git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
git fetch --no-tags linux-stable-rc linux-5.15.y
git checkout e16cc79b0f916069de223bdb567fa0bc2ccd18a5
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash

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

All warnings (new ones prefixed by >>):

>> arch/arm/lib/xor-neon.c:30:2: warning: This code requires at least version 4.6 of GCC [-W#warnings]
#warning This code requires at least version 4.6 of GCC
^
1 warning generated.

vim +30 arch/arm/lib/xor-neon.c

01956597cbc46d Ard Biesheuvel 2013-05-17 16
01956597cbc46d Ard Biesheuvel 2013-05-17 17 /*
01956597cbc46d Ard Biesheuvel 2013-05-17 18 * Pull in the reference implementations while instructing GCC (through
01956597cbc46d Ard Biesheuvel 2013-05-17 19 * -ftree-vectorize) to attempt to exploit implicit parallelism and emit
01956597cbc46d Ard Biesheuvel 2013-05-17 20 * NEON instructions.
01956597cbc46d Ard Biesheuvel 2013-05-17 21 */
01956597cbc46d Ard Biesheuvel 2013-05-17 22 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
01956597cbc46d Ard Biesheuvel 2013-05-17 23 #pragma GCC optimize "tree-vectorize"
01956597cbc46d Ard Biesheuvel 2013-05-17 24 #else
01956597cbc46d Ard Biesheuvel 2013-05-17 25 /*
01956597cbc46d Ard Biesheuvel 2013-05-17 26 * While older versions of GCC do not generate incorrect code, they fail to
01956597cbc46d Ard Biesheuvel 2013-05-17 27 * recognize the parallel nature of these functions, and emit plain ARM code,
01956597cbc46d Ard Biesheuvel 2013-05-17 28 * which is known to be slower than the optimized ARM code in asm-arm/xor.h.
01956597cbc46d Ard Biesheuvel 2013-05-17 29 */
01956597cbc46d Ard Biesheuvel 2013-05-17 @30 #warning This code requires at least version 4.6 of GCC
01956597cbc46d Ard Biesheuvel 2013-05-17 31 #endif
01956597cbc46d Ard Biesheuvel 2013-05-17 32

:::::: The code at line 30 was first introduced by commit
:::::: 01956597cbc46df072f20f90a40eebe356200c38 ARM: crypto: add NEON accelerated XOR implementation

:::::: TO: Ard Biesheuvel <ard.biesheuvel@linaro.org>
:::::: CC: Ard Biesheuvel <ard.biesheuvel@linaro.org>

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