Performing C++ SOURCE FILE Test BUILTIN_ATOMIC failed with the following output:
Change Dir: /home/buildroot/autobuild/instance-3/output-1/build/z3-4.12.1/buildroot-build/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/gmake -f Makefile cmTC_6c3f2/fast && gmake[1]: Entering directory '/home/buildroot/autobuild/instance-3/output-1/build/z3-4.12.1/buildroot-build/CMakeFiles/CMakeTmp'
/usr/bin/gmake  -f CMakeFiles/cmTC_6c3f2.dir/build.make CMakeFiles/cmTC_6c3f2.dir/build
gmake[2]: Entering directory '/home/buildroot/autobuild/instance-3/output-1/build/z3-4.12.1/buildroot-build/CMakeFiles/CMakeTmp'
Building CXX object CMakeFiles/cmTC_6c3f2.dir/src.cxx.o
/home/buildroot/autobuild/instance-3/output-1/host/bin/or1k-buildroot-linux-musl-g++ --sysroot=/home/buildroot/autobuild/instance-3/output-1/host/or1k-buildroot-linux-musl/sysroot -DBUILTIN_ATOMIC  -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O0 -g0 -static -static -Werror=odr    -DNDEBUG -o CMakeFiles/cmTC_6c3f2.dir/src.cxx.o -c /home/buildroot/autobuild/instance-3/output-1/build/z3-4.12.1/buildroot-build/CMakeFiles/CMakeTmp/src.cxx
Linking CXX executable cmTC_6c3f2
/home/buildroot/autobuild/instance-3/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_6c3f2.dir/link.txt --verbose=1
/home/buildroot/autobuild/instance-3/output-1/host/bin/or1k-buildroot-linux-musl-g++ --sysroot=/home/buildroot/autobuild/instance-3/output-1/host/or1k-buildroot-linux-musl/sysroot -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -O0 -g0 -static -static -Werror=odr    -DNDEBUG -static  CMakeFiles/cmTC_6c3f2.dir/src.cxx.o -o cmTC_6c3f2 
/home/buildroot/autobuild/instance-3/output-1/host/lib/gcc/or1k-buildroot-linux-musl/12.2.0/../../../../or1k-buildroot-linux-musl/bin/ld: CMakeFiles/cmTC_6c3f2.dir/src.cxx.o: in function `std::__atomic_base<long long>::operator++()':
src.cxx:(.text._ZNSt13__atomic_baseIxEppEv[_ZNSt13__atomic_baseIxEppEv]+0x54): undefined reference to `__atomic_fetch_add_8'
collect2: error: ld returned 1 exit status
gmake[2]: *** [CMakeFiles/cmTC_6c3f2.dir/build.make:99: cmTC_6c3f2] Error 1
gmake[2]: Leaving directory '/home/buildroot/autobuild/instance-3/output-1/build/z3-4.12.1/buildroot-build/CMakeFiles/CMakeTmp'
gmake[1]: *** [Makefile:127: cmTC_6c3f2/fast] Error 2
gmake[1]: Leaving directory '/home/buildroot/autobuild/instance-3/output-1/build/z3-4.12.1/buildroot-build/CMakeFiles/CMakeTmp'


Source file was:

#include <atomic>
std::atomic<int> x;
std::atomic<short> y;
std::atomic<char> z;
std::atomic<long long> w;
int main() {
	++z;
	++y;
    ++w;
	return ++x;
}