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* arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used
@ 2023-05-22 19:00 kernel test robot
  2023-06-14 14:11 ` Christophe Leroy
  0 siblings, 1 reply; 5+ messages in thread
From: kernel test robot @ 2023-05-22 19:00 UTC (permalink / raw)
  To: Christophe Leroy
  Cc: llvm, oe-kbuild-all, linux-kernel, Michael Ellerman, Nathan Chancellor

Hi Christophe,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   44c026a73be8038f03dbdeef028b642880cf1511
commit: 7245fc5bb7a966852d5bd7779d1f5855530b461a powerpc/math-emu: Remove -w build flag and fix warnings
date:   9 months ago
config: powerpc-randconfig-r022-20230522 (https://download.01.org/0day-ci/archive/20230523/202305230231.3Wb7Q68G-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project b0fb98227c90adf2536c9ad644a74d5e92961111)
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 powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7245fc5bb7a966852d5bd7779d1f5855530b461a
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 7245fc5bb7a966852d5bd7779d1f5855530b461a
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/math-emu/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202305230231.3Wb7Q68G-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used [-Wunused-but-set-variable]
           FP_DECL_D(A);
           ^
   include/math-emu/double.h:73:23: note: expanded from macro 'FP_DECL_D'
   #define FP_DECL_D(X)            _FP_DECL(2,X)
                                   ^
   include/math-emu/op-common.h:28:14: note: expanded from macro '_FP_DECL'
     _FP_I_TYPE X##_c=0, X##_s=0, X##_e=0; \
                ^
   <scratch space>:124:1: note: expanded from here
   A_c
   ^
>> arch/powerpc/math-emu/fcmpu.c:14:2: warning: variable 'B_c' set but not used [-Wunused-but-set-variable]
           FP_DECL_D(B);
           ^
   include/math-emu/double.h:73:23: note: expanded from macro 'FP_DECL_D'
   #define FP_DECL_D(X)            _FP_DECL(2,X)
                                   ^
   include/math-emu/op-common.h:28:14: note: expanded from macro '_FP_DECL'
     _FP_I_TYPE X##_c=0, X##_s=0, X##_e=0; \
                ^
   <scratch space>:130:1: note: expanded from here
   B_c
   ^
>> arch/powerpc/math-emu/fcmpu.c:15:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
           FP_DECL_EX;
           ^
   include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
   #define FP_DECL_EX int _fex = 0
                          ^
   arch/powerpc/math-emu/fcmpu.c:11:1: warning: no previous prototype for function 'fcmpu' [-Wmissing-prototypes]
   fcmpu(u32 *ccr, int crfD, void *frA, void *frB)
   ^
   arch/powerpc/math-emu/fcmpu.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int
   ^
   static 
   4 warnings generated.
--
>> arch/powerpc/math-emu/fctiw.c:14:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
           FP_DECL_EX;
           ^
   include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
   #define FP_DECL_EX int _fex = 0
                          ^
   arch/powerpc/math-emu/fctiw.c:11:1: warning: no previous prototype for function 'fctiw' [-Wmissing-prototypes]
   fctiw(u32 *frD, void *frB)
   ^
   arch/powerpc/math-emu/fctiw.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int
   ^
   static 
   2 warnings generated.
--
>> arch/powerpc/math-emu/fctiwz.c:14:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
           FP_DECL_EX;
           ^
   include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
   #define FP_DECL_EX int _fex = 0
                          ^
   arch/powerpc/math-emu/fctiwz.c:11:1: warning: no previous prototype for function 'fctiwz' [-Wmissing-prototypes]
   fctiwz(u32 *frD, void *frB)
   ^
   arch/powerpc/math-emu/fctiwz.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int
   ^
   static 
   2 warnings generated.
--
>> arch/powerpc/math-emu/fsel.c:14:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
           FP_DECL_EX;
           ^
   include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
   #define FP_DECL_EX int _fex = 0
                          ^
   arch/powerpc/math-emu/fsel.c:11:1: warning: no previous prototype for function 'fsel' [-Wmissing-prototypes]
   fsel(u32 *frD, void *frA, u32 *frB, u32 *frC)
   ^
   arch/powerpc/math-emu/fsel.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int
   ^
   static 
   2 warnings generated.


vim +/A_c +13 arch/powerpc/math-emu/fcmpu.c

^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16   9  
^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  10  int
^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  11  fcmpu(u32 *ccr, int crfD, void *frA, void *frB)
^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  12  {
^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16 @13  	FP_DECL_D(A);
^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16 @14  	FP_DECL_D(B);
d2b194ed820880 arch/powerpc/math-emu/fcmpu.c Kumar Gala     2008-06-04 @15  	FP_DECL_EX;
^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  16  	int code[4] = { (1 << 3), (1 << 1), (1 << 2), (1 << 0) };
^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  17  	long cmp;
^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  18  

:::::: The code at line 13 was first introduced by commit
:::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2

:::::: TO: Linus Torvalds <torvalds@ppc970.osdl.org>
:::::: CC: Linus Torvalds <torvalds@ppc970.osdl.org>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used
  2023-05-22 19:00 arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used kernel test robot
@ 2023-06-14 14:11 ` Christophe Leroy
  2023-06-14 16:04   ` Nick Desaulniers
  0 siblings, 1 reply; 5+ messages in thread
From: Christophe Leroy @ 2023-06-14 14:11 UTC (permalink / raw)
  To: kernel test robot
  Cc: llvm, oe-kbuild-all, linux-kernel, Michael Ellerman, Nathan Chancellor

Hi,

Le 22/05/2023 à 21:00, kernel test robot a écrit :
> Hi Christophe,
> 
> FYI, the error/warning still remains.
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   44c026a73be8038f03dbdeef028b642880cf1511
> commit: 7245fc5bb7a966852d5bd7779d1f5855530b461a powerpc/math-emu: Remove -w build flag and fix warnings
> date:   9 months ago
> config: powerpc-randconfig-r022-20230522 (https://download.01.org/0day-ci/archive/20230523/202305230231.3Wb7Q68G-lkp@intel.com/config)
> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project b0fb98227c90adf2536c9ad644a74d5e92961111)
> 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 powerpc cross compiling tool for clang build
>          # apt-get install binutils-powerpc-linux-gnu
>          # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7245fc5bb7a966852d5bd7779d1f5855530b461a
>          git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>          git fetch --no-tags linus master
>          git checkout 7245fc5bb7a966852d5bd7779d1f5855530b461a
>          # save the config file
>          mkdir build_dir && cp config build_dir/.config
>          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
>          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/math-emu/
> 
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202305230231.3Wb7Q68G-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>>> arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used [-Wunused-but-set-variable]

This code is imported, and there is no plan to make any change to it. 
Can you desactivate that warning ?

Thanks
Christophe

>             FP_DECL_D(A);
>             ^
>     include/math-emu/double.h:73:23: note: expanded from macro 'FP_DECL_D'
>     #define FP_DECL_D(X)            _FP_DECL(2,X)
>                                     ^
>     include/math-emu/op-common.h:28:14: note: expanded from macro '_FP_DECL'
>       _FP_I_TYPE X##_c=0, X##_s=0, X##_e=0; \
>                  ^
>     <scratch space>:124:1: note: expanded from here
>     A_c
>     ^
>>> arch/powerpc/math-emu/fcmpu.c:14:2: warning: variable 'B_c' set but not used [-Wunused-but-set-variable]
>             FP_DECL_D(B);
>             ^
>     include/math-emu/double.h:73:23: note: expanded from macro 'FP_DECL_D'
>     #define FP_DECL_D(X)            _FP_DECL(2,X)
>                                     ^
>     include/math-emu/op-common.h:28:14: note: expanded from macro '_FP_DECL'
>       _FP_I_TYPE X##_c=0, X##_s=0, X##_e=0; \
>                  ^
>     <scratch space>:130:1: note: expanded from here
>     B_c
>     ^
>>> arch/powerpc/math-emu/fcmpu.c:15:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
>             FP_DECL_EX;
>             ^
>     include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
>     #define FP_DECL_EX int _fex = 0
>                            ^
>     arch/powerpc/math-emu/fcmpu.c:11:1: warning: no previous prototype for function 'fcmpu' [-Wmissing-prototypes]
>     fcmpu(u32 *ccr, int crfD, void *frA, void *frB)
>     ^
>     arch/powerpc/math-emu/fcmpu.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>     int
>     ^
>     static
>     4 warnings generated.
> --
>>> arch/powerpc/math-emu/fctiw.c:14:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
>             FP_DECL_EX;
>             ^
>     include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
>     #define FP_DECL_EX int _fex = 0
>                            ^
>     arch/powerpc/math-emu/fctiw.c:11:1: warning: no previous prototype for function 'fctiw' [-Wmissing-prototypes]
>     fctiw(u32 *frD, void *frB)
>     ^
>     arch/powerpc/math-emu/fctiw.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>     int
>     ^
>     static
>     2 warnings generated.
> --
>>> arch/powerpc/math-emu/fctiwz.c:14:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
>             FP_DECL_EX;
>             ^
>     include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
>     #define FP_DECL_EX int _fex = 0
>                            ^
>     arch/powerpc/math-emu/fctiwz.c:11:1: warning: no previous prototype for function 'fctiwz' [-Wmissing-prototypes]
>     fctiwz(u32 *frD, void *frB)
>     ^
>     arch/powerpc/math-emu/fctiwz.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>     int
>     ^
>     static
>     2 warnings generated.
> --
>>> arch/powerpc/math-emu/fsel.c:14:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
>             FP_DECL_EX;
>             ^
>     include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
>     #define FP_DECL_EX int _fex = 0
>                            ^
>     arch/powerpc/math-emu/fsel.c:11:1: warning: no previous prototype for function 'fsel' [-Wmissing-prototypes]
>     fsel(u32 *frD, void *frA, u32 *frB, u32 *frC)
>     ^
>     arch/powerpc/math-emu/fsel.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>     int
>     ^
>     static
>     2 warnings generated.
> 
> 
> vim +/A_c +13 arch/powerpc/math-emu/fcmpu.c
> 
> ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16   9
> ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  10  int
> ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  11  fcmpu(u32 *ccr, int crfD, void *frA, void *frB)
> ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  12  {
> ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16 @13  	FP_DECL_D(A);
> ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16 @14  	FP_DECL_D(B);
> d2b194ed820880 arch/powerpc/math-emu/fcmpu.c Kumar Gala     2008-06-04 @15  	FP_DECL_EX;
> ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  16  	int code[4] = { (1 << 3), (1 << 1), (1 << 2), (1 << 0) };
> ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  17  	long cmp;
> ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  18
> 
> :::::: The code at line 13 was first introduced by commit
> :::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2
> 
> :::::: TO: Linus Torvalds <torvalds@ppc970.osdl.org>
> :::::: CC: Linus Torvalds <torvalds@ppc970.osdl.org>
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used
  2023-06-14 14:11 ` Christophe Leroy
@ 2023-06-14 16:04   ` Nick Desaulniers
  2023-06-14 18:26     ` Christophe Leroy
  0 siblings, 1 reply; 5+ messages in thread
From: Nick Desaulniers @ 2023-06-14 16:04 UTC (permalink / raw)
  To: Christophe Leroy
  Cc: kernel test robot, llvm, oe-kbuild-all, linux-kernel,
	Michael Ellerman, Nathan Chancellor

On Wed, Jun 14, 2023 at 10:11 AM Christophe Leroy
<christophe.leroy@csgroup.eu> wrote:
>
> Hi,
>
> Le 22/05/2023 à 21:00, kernel test robot a écrit :
> > Hi Christophe,
> >
> > FYI, the error/warning still remains.
> >
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   44c026a73be8038f03dbdeef028b642880cf1511
> > commit: 7245fc5bb7a966852d5bd7779d1f5855530b461a powerpc/math-emu: Remove -w build flag and fix warnings
> > date:   9 months ago
> > config: powerpc-randconfig-r022-20230522 (https://download.01.org/0day-ci/archive/20230523/202305230231.3Wb7Q68G-lkp@intel.com/config)
> > compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project b0fb98227c90adf2536c9ad644a74d5e92961111)
> > 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 powerpc cross compiling tool for clang build
> >          # apt-get install binutils-powerpc-linux-gnu
> >          # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7245fc5bb7a966852d5bd7779d1f5855530b461a
> >          git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> >          git fetch --no-tags linus master
> >          git checkout 7245fc5bb7a966852d5bd7779d1f5855530b461a
> >          # save the config file
> >          mkdir build_dir && cp config build_dir/.config
> >          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
> >          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/math-emu/
> >
> > If you fix the issue, kindly add following tag where applicable
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202305230231.3Wb7Q68G-lkp@intel.com/
> >
> > All warnings (new ones prefixed by >>):
> >
> >>> arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used [-Wunused-but-set-variable]
>
> This code is imported, and there is no plan to make any change to it.
> Can you desactivate that warning ?

If the code is imported, and we don't plan to push fixes upstream,
does it make sense to just set -Wno-unusued-but-set-variable in
arch/powerpc/math-emu/Makefile?

Wait, what?!
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/math-emu/Makefile#n20
arch/powerpc/math-emu/Makefile already has -Wunused-but-set-variable
in ccflags-remove-y. But if KBUILD_EXTRA_WARN is set for W=1 builds,
-Wunused-but-set-variable is added back, but only for math.o and
math_efp.o.  The warning above comes from building fcmpu.o.  So how
did  -Wunused-but-set-variable get set in the first place?

commit 78c73c80fd86 ("powerpc/math-emu: Inhibit W=1 warnings")
seems to have cleaned up this code for W=1 with GCC. This report is a
result of W=1 with CC=clang.

>
> Thanks
> Christophe
>
> >             FP_DECL_D(A);
> >             ^
> >     include/math-emu/double.h:73:23: note: expanded from macro 'FP_DECL_D'
> >     #define FP_DECL_D(X)            _FP_DECL(2,X)
> >                                     ^
> >     include/math-emu/op-common.h:28:14: note: expanded from macro '_FP_DECL'
> >       _FP_I_TYPE X##_c=0, X##_s=0, X##_e=0; \
> >                  ^
> >     <scratch space>:124:1: note: expanded from here
> >     A_c
> >     ^
> >>> arch/powerpc/math-emu/fcmpu.c:14:2: warning: variable 'B_c' set but not used [-Wunused-but-set-variable]
> >             FP_DECL_D(B);
> >             ^
> >     include/math-emu/double.h:73:23: note: expanded from macro 'FP_DECL_D'
> >     #define FP_DECL_D(X)            _FP_DECL(2,X)
> >                                     ^
> >     include/math-emu/op-common.h:28:14: note: expanded from macro '_FP_DECL'
> >       _FP_I_TYPE X##_c=0, X##_s=0, X##_e=0; \
> >                  ^
> >     <scratch space>:130:1: note: expanded from here
> >     B_c
> >     ^
> >>> arch/powerpc/math-emu/fcmpu.c:15:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
> >             FP_DECL_EX;
> >             ^
> >     include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
> >     #define FP_DECL_EX int _fex = 0
> >                            ^
> >     arch/powerpc/math-emu/fcmpu.c:11:1: warning: no previous prototype for function 'fcmpu' [-Wmissing-prototypes]
> >     fcmpu(u32 *ccr, int crfD, void *frA, void *frB)
> >     ^
> >     arch/powerpc/math-emu/fcmpu.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
> >     int
> >     ^
> >     static
> >     4 warnings generated.
> > --
> >>> arch/powerpc/math-emu/fctiw.c:14:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
> >             FP_DECL_EX;
> >             ^
> >     include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
> >     #define FP_DECL_EX int _fex = 0
> >                            ^
> >     arch/powerpc/math-emu/fctiw.c:11:1: warning: no previous prototype for function 'fctiw' [-Wmissing-prototypes]
> >     fctiw(u32 *frD, void *frB)
> >     ^
> >     arch/powerpc/math-emu/fctiw.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
> >     int
> >     ^
> >     static
> >     2 warnings generated.
> > --
> >>> arch/powerpc/math-emu/fctiwz.c:14:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
> >             FP_DECL_EX;
> >             ^
> >     include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
> >     #define FP_DECL_EX int _fex = 0
> >                            ^
> >     arch/powerpc/math-emu/fctiwz.c:11:1: warning: no previous prototype for function 'fctiwz' [-Wmissing-prototypes]
> >     fctiwz(u32 *frD, void *frB)
> >     ^
> >     arch/powerpc/math-emu/fctiwz.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
> >     int
> >     ^
> >     static
> >     2 warnings generated.
> > --
> >>> arch/powerpc/math-emu/fsel.c:14:2: warning: variable '_fex' set but not used [-Wunused-but-set-variable]
> >             FP_DECL_EX;
> >             ^
> >     include/math-emu/soft-fp.h:94:24: note: expanded from macro 'FP_DECL_EX'
> >     #define FP_DECL_EX int _fex = 0
> >                            ^
> >     arch/powerpc/math-emu/fsel.c:11:1: warning: no previous prototype for function 'fsel' [-Wmissing-prototypes]
> >     fsel(u32 *frD, void *frA, u32 *frB, u32 *frC)
> >     ^
> >     arch/powerpc/math-emu/fsel.c:10:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
> >     int
> >     ^
> >     static
> >     2 warnings generated.
> >
> >
> > vim +/A_c +13 arch/powerpc/math-emu/fcmpu.c
> >
> > ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16   9
> > ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  10  int
> > ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  11  fcmpu(u32 *ccr, int crfD, void *frA, void *frB)
> > ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  12  {
> > ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16 @13    FP_DECL_D(A);
> > ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16 @14    FP_DECL_D(B);
> > d2b194ed820880 arch/powerpc/math-emu/fcmpu.c Kumar Gala     2008-06-04 @15    FP_DECL_EX;
> > ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  16    int code[4] = { (1 << 3), (1 << 1), (1 << 2), (1 << 0) };
> > ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  17    long cmp;
> > ^1da177e4c3f41 arch/ppc/math-emu/fcmpu.c     Linus Torvalds 2005-04-16  18
> >
> > :::::: The code at line 13 was first introduced by commit
> > :::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2
> >
> > :::::: TO: Linus Torvalds <torvalds@ppc970.osdl.org>
> > :::::: CC: Linus Torvalds <torvalds@ppc970.osdl.org>
> >



-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used
  2023-06-14 16:04   ` Nick Desaulniers
@ 2023-06-14 18:26     ` Christophe Leroy
  2023-06-14 18:51       ` Nick Desaulniers
  0 siblings, 1 reply; 5+ messages in thread
From: Christophe Leroy @ 2023-06-14 18:26 UTC (permalink / raw)
  To: Nick Desaulniers
  Cc: kernel test robot, llvm, oe-kbuild-all, linux-kernel,
	Michael Ellerman, Nathan Chancellor



Le 14/06/2023 à 18:04, Nick Desaulniers a écrit :
> On Wed, Jun 14, 2023 at 10:11 AM Christophe Leroy
> <christophe.leroy@csgroup.eu> wrote:
>>
>> Hi,
>>
>> Le 22/05/2023 à 21:00, kernel test robot a écrit :
>>> Hi Christophe,
>>>
>>> FYI, the error/warning still remains.
>>>
>>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>>> head:   44c026a73be8038f03dbdeef028b642880cf1511
>>> commit: 7245fc5bb7a966852d5bd7779d1f5855530b461a powerpc/math-emu: Remove -w build flag and fix warnings
>>> date:   9 months ago
>>> config: powerpc-randconfig-r022-20230522 (https://download.01.org/0day-ci/archive/20230523/202305230231.3Wb7Q68G-lkp@intel.com/config)
>>> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project b0fb98227c90adf2536c9ad644a74d5e92961111)
>>> 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 powerpc cross compiling tool for clang build
>>>           # apt-get install binutils-powerpc-linux-gnu
>>>           # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7245fc5bb7a966852d5bd7779d1f5855530b461a
>>>           git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>>           git fetch --no-tags linus master
>>>           git checkout 7245fc5bb7a966852d5bd7779d1f5855530b461a
>>>           # save the config file
>>>           mkdir build_dir && cp config build_dir/.config
>>>           COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
>>>           COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/math-emu/
>>>
>>> If you fix the issue, kindly add following tag where applicable
>>> | Reported-by: kernel test robot <lkp@intel.com>
>>> | Closes: https://lore.kernel.org/oe-kbuild-all/202305230231.3Wb7Q68G-lkp@intel.com/
>>>
>>> All warnings (new ones prefixed by >>):
>>>
>>>>> arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used [-Wunused-but-set-variable]
>>
>> This code is imported, and there is no plan to make any change to it.
>> Can you desactivate that warning ?
> 
> If the code is imported, and we don't plan to push fixes upstream,
> does it make sense to just set -Wno-unusued-but-set-variable in
> arch/powerpc/math-emu/Makefile?

Yes, that's done already but clang ignores it apparently.

> 
> Wait, what?!
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/math-emu/Makefile#n20
> arch/powerpc/math-emu/Makefile already has -Wunused-but-set-variable
> in ccflags-remove-y. But if KBUILD_EXTRA_WARN is set for W=1 builds,
> -Wunused-but-set-variable is added back, but only for math.o and
> math_efp.o.  The warning above comes from building fcmpu.o.  So how
> did  -Wunused-but-set-variable get set in the first place?

Indeed.

I looked once more and found out that:

   clang -Wp,-MMD,arch/powerpc/math-emu/.fcmpu.o.d -nostdinc 
-I./arch/powerpc/include -I./arch/powerpc/include/generated  -I./include 
-I./arch/powerpc/include/uapi -I./arch/powerpc/include/generated/uapi 
-I./include/uapi -I./include/generated/uapi -include 
./include/linux/compiler-version.h -include ./include/linux/kconfig.h 
-include ./include/linux/compiler_types.h -D__KERNEL__ -I ./arch/powerpc 
-DHAVE_AS_ATHIGH=1 -fmacro-prefix-map=./= -Wundef -DKBUILD_EXTRA_WARN1 
-Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs 
-fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE 
-Werror=implicit-function-declaration -Werror=implicit-int 
-Werror=return-type -Wno-format-security -funsigned-char -std=gnu11 
--target=powerpc64le-linux-gnu -fintegrated-as 
-Werror=unknown-warning-option -Werror=ignored-optimization-argument 
-Werror=option-ignored -Werror=unused-command-line-argument -mbig-endian 
-m32 -msoft-float -pipe -mcpu=powerpc -mno-prefixed -mno-pcrel 
-mno-altivec -mno-vsx -mno-mma -mno-spe -fno-asynchronous-unwind-tables 
-mbig-endian -fno-delete-null-pointer-checks -Wno-frame-address 
-Wno-address-of-packed-member -O2 -Wframe-larger-than=1024 
-fno-stack-protector -Wno-gnu -Wno-unused-but-set-variable 
-Wno-unused-const-variable -ftrivial-auto-var-init=zero 
-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang 
-pg -Wdeclaration-after-statement -Wvla -Wno-pointer-sign 
-Wcast-function-type -Wimplicit-fallthrough -fno-strict-overflow 
-fno-stack-check -Werror=date-time -Werror=incompatible-pointer-types 
-Wextra -Wunused -Wno-unused-parameter -Wmissing-format-attribute 
-Wold-style-definition -Wmissing-include-dirs -Wunused-const-variable 
-Wno-missing-field-initializers -Wno-sign-compare -Wno-type-limits 
-Wno-shift-negative-value -g -Werror 
-DKBUILD_MODFILE='"arch/powerpc/math-emu/fcmpu"' 
-DKBUILD_BASENAME='"fcmpu"' -DKBUILD_MODNAME='"fcmpu"' 
-D__KBUILD_MODNAME=kmod_fcmpu -c -o arch/powerpc/math-emu/fcmpu.o 
arch/powerpc/math-emu/fcmpu.c   ; ./tools/objtool/objtool --mcount 
--uaccess --sec-address   arch/powerpc/math-emu/fcmpu.o


If you move -Wunused before -Wno-unused-but-set-variable, then you don't 
have the warning/error anymore. So what ? What the hell is clang 
behaving that way ?

GCC documentation is explicit, see 
https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html :

   The combined effect of positive and negative forms is that more 
specific options have priority over less specific ones, independently of 
their position in the command-line.

Can clang be fixed ?

Christophe

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used
  2023-06-14 18:26     ` Christophe Leroy
@ 2023-06-14 18:51       ` Nick Desaulniers
  0 siblings, 0 replies; 5+ messages in thread
From: Nick Desaulniers @ 2023-06-14 18:51 UTC (permalink / raw)
  To: Christophe Leroy
  Cc: kernel test robot, llvm, oe-kbuild-all, linux-kernel,
	Michael Ellerman, Nathan Chancellor

On Wed, Jun 14, 2023 at 2:26 PM Christophe Leroy
<christophe.leroy@csgroup.eu> wrote:
>
>
>
> Le 14/06/2023 à 18:04, Nick Desaulniers a écrit :
> > On Wed, Jun 14, 2023 at 10:11 AM Christophe Leroy
> > <christophe.leroy@csgroup.eu> wrote:
> >>
> >> Hi,
> >>
> >> Le 22/05/2023 à 21:00, kernel test robot a écrit :
> >>> Hi Christophe,
> >>>
> >>> FYI, the error/warning still remains.
> >>>
> >>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> >>> head:   44c026a73be8038f03dbdeef028b642880cf1511
> >>> commit: 7245fc5bb7a966852d5bd7779d1f5855530b461a powerpc/math-emu: Remove -w build flag and fix warnings
> >>> date:   9 months ago
> >>> config: powerpc-randconfig-r022-20230522 (https://download.01.org/0day-ci/archive/20230523/202305230231.3Wb7Q68G-lkp@intel.com/config)
> >>> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project b0fb98227c90adf2536c9ad644a74d5e92961111)
> >>> 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 powerpc cross compiling tool for clang build
> >>>           # apt-get install binutils-powerpc-linux-gnu
> >>>           # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7245fc5bb7a966852d5bd7779d1f5855530b461a
> >>>           git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> >>>           git fetch --no-tags linus master
> >>>           git checkout 7245fc5bb7a966852d5bd7779d1f5855530b461a
> >>>           # save the config file
> >>>           mkdir build_dir && cp config build_dir/.config
> >>>           COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
> >>>           COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/math-emu/
> >>>
> >>> If you fix the issue, kindly add following tag where applicable
> >>> | Reported-by: kernel test robot <lkp@intel.com>
> >>> | Closes: https://lore.kernel.org/oe-kbuild-all/202305230231.3Wb7Q68G-lkp@intel.com/
> >>>
> >>> All warnings (new ones prefixed by >>):
> >>>
> >>>>> arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used [-Wunused-but-set-variable]
> >>
> >> This code is imported, and there is no plan to make any change to it.
> >> Can you desactivate that warning ?
> >
> > If the code is imported, and we don't plan to push fixes upstream,
> > does it make sense to just set -Wno-unusued-but-set-variable in
> > arch/powerpc/math-emu/Makefile?
>
> Yes, that's done already but clang ignores it apparently.
>
> >
> > Wait, what?!
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/math-emu/Makefile#n20
> > arch/powerpc/math-emu/Makefile already has -Wunused-but-set-variable
> > in ccflags-remove-y. But if KBUILD_EXTRA_WARN is set for W=1 builds,
> > -Wunused-but-set-variable is added back, but only for math.o and
> > math_efp.o.  The warning above comes from building fcmpu.o.  So how
> > did  -Wunused-but-set-variable get set in the first place?
>
> Indeed.
>
> I looked once more and found out that:
>
>    clang -Wp,-MMD,arch/powerpc/math-emu/.fcmpu.o.d -nostdinc
> -I./arch/powerpc/include -I./arch/powerpc/include/generated  -I./include
> -I./arch/powerpc/include/uapi -I./arch/powerpc/include/generated/uapi
> -I./include/uapi -I./include/generated/uapi -include
> ./include/linux/compiler-version.h -include ./include/linux/kconfig.h
> -include ./include/linux/compiler_types.h -D__KERNEL__ -I ./arch/powerpc
> -DHAVE_AS_ATHIGH=1 -fmacro-prefix-map=./= -Wundef -DKBUILD_EXTRA_WARN1
> -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs
> -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE
> -Werror=implicit-function-declaration -Werror=implicit-int
> -Werror=return-type -Wno-format-security -funsigned-char -std=gnu11
> --target=powerpc64le-linux-gnu -fintegrated-as
> -Werror=unknown-warning-option -Werror=ignored-optimization-argument
> -Werror=option-ignored -Werror=unused-command-line-argument -mbig-endian
> -m32 -msoft-float -pipe -mcpu=powerpc -mno-prefixed -mno-pcrel
> -mno-altivec -mno-vsx -mno-mma -mno-spe -fno-asynchronous-unwind-tables
> -mbig-endian -fno-delete-null-pointer-checks -Wno-frame-address
> -Wno-address-of-packed-member -O2 -Wframe-larger-than=1024
> -fno-stack-protector -Wno-gnu -Wno-unused-but-set-variable
> -Wno-unused-const-variable -ftrivial-auto-var-init=zero
> -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
> -pg -Wdeclaration-after-statement -Wvla -Wno-pointer-sign
> -Wcast-function-type -Wimplicit-fallthrough -fno-strict-overflow
> -fno-stack-check -Werror=date-time -Werror=incompatible-pointer-types
> -Wextra -Wunused -Wno-unused-parameter -Wmissing-format-attribute
> -Wold-style-definition -Wmissing-include-dirs -Wunused-const-variable
> -Wno-missing-field-initializers -Wno-sign-compare -Wno-type-limits
> -Wno-shift-negative-value -g -Werror
> -DKBUILD_MODFILE='"arch/powerpc/math-emu/fcmpu"'
> -DKBUILD_BASENAME='"fcmpu"' -DKBUILD_MODNAME='"fcmpu"'
> -D__KBUILD_MODNAME=kmod_fcmpu -c -o arch/powerpc/math-emu/fcmpu.o
> arch/powerpc/math-emu/fcmpu.c   ; ./tools/objtool/objtool --mcount
> --uaccess --sec-address   arch/powerpc/math-emu/fcmpu.o
>
>
> If you move -Wunused before -Wno-unused-but-set-variable, then you don't
> have the warning/error anymore. So what ? What the hell is clang
> behaving that way ?

It's re-enabling ALL of the members of the -Wunused group without
having checked to see if any more specific members were already
disabled.

>
> GCC documentation is explicit, see
> https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html :
>
>    The combined effect of positive and negative forms is that more
> specific options have priority over less specific ones, independently of
> their position in the command-line.

Ah, nice citation. I did not know that was the expected behavior of
this group diagnostics.  Indeed, there's a behavior difference here.
https://godbolt.org/z/13MxqrjcW

>
> Can clang be fixed ?

Filed:
https://github.com/llvm/llvm-project/issues/63315

>
> Christophe



-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2023-06-14 18:52 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-05-22 19:00 arch/powerpc/math-emu/fcmpu.c:13:2: warning: variable 'A_c' set but not used kernel test robot
2023-06-14 14:11 ` Christophe Leroy
2023-06-14 16:04   ` Nick Desaulniers
2023-06-14 18:26     ` Christophe Leroy
2023-06-14 18:51       ` Nick Desaulniers

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