Messages in this thread | | | Date | Sun, 30 Jul 2023 10:05:46 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH next v2 2/5] minmax: Allow min()/max()/clamp() if the arguments have the same signedness. |
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On Sun, Jul 30, 2023 at 02:55:50PM +0000, David Laight wrote: > From: kernel test robot > > Sent: 29 July 2023 03:01 > > > > kernel test robot noticed the following build errors: > > > ...) > > compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git > > 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a) > > reproduce: (https://download.01.org/0day-ci/archive/20230729/202307290943.ODVeyeK6- > > lkp@intel.com/reproduce) > > > ... > > >> mm/percpu.c:3102:10: error: static assertion expression is not an integral constant expression > > base = min(ptr, base); > > ^~~~~~~~~~~~~~ > ... ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~ > > include/linux/minmax.h:23:2: note: expanded from macro '__types_ok' > > (is_signed_type(typeof(x)) == is_signed_type(typeof(y))) > > ^ > ... > > mm/percpu.c:3102:10: note: cast that performs the conversions of a reinterpret_cast is not allowed > > in a constant expression > > That is a C++ error that seems to have crept into C. > The relevant definition is: > > #define is_signed_type(type) (((type)(-1)) < (type)1) > > This seems to have been fixed in clang 16.0.0.
Indeed, it looks like
https://github.com/llvm/llvm-project/commit/a181de452df311d7647329120d05f4eb9c158b6c
fixed this as a result of the discussion at
https://github.com/llvm/llvm-project/issues/57687, which certainly makes sense.
Cheers, Nathan
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