Bug#1127626: libxsimd-dev: clang errors on ppc64el

[Drew Parsons]

On 2026-02-10 18:56, Jeffrey Walton wrote:
> On Tue, Feb 10, 2026 at 12:37 PM Drew Parsons <dparsons at debian.org>
> wrote:
>> 
>> xsimd 14.0.0 tests on ppc64el are passing with gcc 15 but failing
>> with
>> clang 21.
> 
> If I recall correctly... VSX extensions, like vec_vsx_st, were
> optional in POWER7 and part of POWER8.
> 
> My guess is, the problem is `-mcpu=native` while building on a
> downlevel machine.  Instead, the CFLAGS and CXXFLAGS should include
> `-mcpu=power7 -mvsx` or `-mcpu=power8`.
> 
> Someone like David Edelsohn (<dje.gcc at gmail.com>) could probably say
> more about the VSX unit and what flags it requires.


That sounds plausible.  But unfortunately it's not so simple as just 
removing native
or adding -mcpu=power7 (or power8 or power9, the test machine is POWER9 
altivec supported)

Each of the permutation gets the same set of errors, reproducing the 
error from the command line:

$ /usr/bin/clang++   -Wunused-parameter -Wextra -Wreorder 
-Wshorten-64-to-32 -std=c++11 -g -fPIC -O3 -DNDEBUG -MD -MT 
CMakeFiles/test_xsimd.dir/test_api.cpp.o -MF 
CMakeFiles/test_xsimd.dir/test_api.cpp.o.d -o 
CMakeFiles/test_xsimd.dir/test_api.cpp.o -c 
/xsimd/xsimd-14.0.0/test/test_api.cpp 2>&1 | head -n 50
In file included from /xsimd/xsimd-14.0.0/test/test_api.cpp:12:
In file included from /usr/include/xsimd/xsimd.hpp:63:
In file included from 
/usr/include/xsimd/memory/xsimd_aligned_allocator.hpp:27:
In file included from 
/usr/include/xsimd/memory/../config/xsimd_arch.hpp:19:
In file included from 
/usr/include/xsimd/memory/../config/../types/xsimd_all_registers.hpp:51:
/usr/include/xsimd/memory/../config/../types/xsimd_vsx_register.hpp:67:61: 
error: cannot use 'long' with '__vector bool'
    67 |         XSIMD_DECLARE_SIMD_BOOL_VSX_REGISTER(unsigned long, 
long);
       |                                                             ^
/usr/include/xsimd/memory/../config/../types/xsimd_vsx_register.hpp:68:52: 
error: cannot use 'long' with '__vector bool'
    68 |         XSIMD_DECLARE_SIMD_BOOL_VSX_REGISTER(long, long);
       |                                                    ^
/usr/include/xsimd/memory/../config/../types/xsimd_vsx_register.hpp:70:54: 
error: cannot use 'long' with '__vector bool'
    70 |         XSIMD_DECLARE_SIMD_BOOL_VSX_REGISTER(double, long);
       |                                                      ^
In file included from /xsimd/xsimd-14.0.0/test/test_api.cpp:12:
In file included from /usr/include/xsimd/xsimd.hpp:77:
In file included from /usr/include/xsimd/types/xsimd_batch.hpp:520:
In file included from 
/usr/include/xsimd/types/../arch/xsimd_isa.hpp:136:
/usr/include/xsimd/types/../arch/./xsimd_vsx.hpp:429:20: error: no 
matching function for call to 'vec_ld'
   429 |             return vec_ld(0, reinterpret_cast<const typename 
batch<T, A>::register_type*>(mem));