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ginkgo-project / ginkgo

Numerical linear algebra software package
https://ginkgo-project.github.io/
BSD 3-Clause "New" or "Revised" License
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Build fails with strict-aliasing violations #1657

Open eli-schwartz opened 2 months ago

eli-schwartz commented 2 months ago

I tried to build with the following *FLAGS to optimize the build: -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing

The -Werror=* flags are important to detect cases where the compiler can try to optimize based on assuming Undefined Behavior (UB) cannot happen, and miscompile code that has UB in it. strict-aliasing issues are always bad but LTO can make them even worse.

I got this error:

[1/51] /usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_reference_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT reference/CMakeFiles/ginkgo_reference.dir/solver/common_gmres_kernels.cpp.o -MF reference/CMakeFiles/ginkgo_reference.dir/solver/common_gmres_kernels.cpp.o.d -o reference/CMakeFiles/ginkgo_reference.dir/solver/common_gmres_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/solver/common_gmres_kernels.cpp
FAILED: reference/CMakeFiles/ginkgo_reference.dir/solver/common_gmres_kernels.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_reference_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT reference/CMakeFiles/ginkgo_reference.dir/solver/common_gmres_kernels.cpp.o -MF reference/CMakeFiles/ginkgo_reference.dir/solver/common_gmres_kernels.cpp.o.d -o reference/CMakeFiles/ginkgo_reference.dir/solver/common_gmres_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/solver/common_gmres_kernels.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres_kernels.hpp:17,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/solver/common_gmres_kernels.cpp:14:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
cc1plus: some warnings being treated as errors
[2/51] /usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_reference_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT reference/CMakeFiles/ginkgo_reference.dir/solver/cb_gmres_kernels.cpp.o -MF reference/CMakeFiles/ginkgo_reference.dir/solver/cb_gmres_kernels.cpp.o.d -o reference/CMakeFiles/ginkgo_reference.dir/solver/cb_gmres_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/solver/cb_gmres_kernels.cpp
FAILED: reference/CMakeFiles/ginkgo_reference.dir/solver/cb_gmres_kernels.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_reference_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT reference/CMakeFiles/ginkgo_reference.dir/solver/cb_gmres_kernels.cpp.o -MF reference/CMakeFiles/ginkgo_reference.dir/solver/cb_gmres_kernels.cpp.o.d -o reference/CMakeFiles/ginkgo_reference.dir/solver/cb_gmres_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/solver/cb_gmres_kernels.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres_kernels.hpp:17,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/solver/cb_gmres_kernels.cpp:5:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
cc1plus: some warnings being treated as errors
[3/51] /usr/bin/x86_64-pc-linux-gnu-g++ -DGKO_COMPILING_OMP -DGKO_DEVICE_NAMESPACE=omp -Dginkgo_omp_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -fopenmp -MD -MT omp/CMakeFiles/ginkgo_omp.dir/__/common/unified/solver/common_gmres_kernels.cpp.o -MF omp/CMakeFiles/ginkgo_omp.dir/__/common/unified/solver/common_gmres_kernels.cpp.o.d -o omp/CMakeFiles/ginkgo_omp.dir/__/common/unified/solver/common_gmres_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/common/unified/solver/common_gmres_kernels.cpp
FAILED: omp/CMakeFiles/ginkgo_omp.dir/__/common/unified/solver/common_gmres_kernels.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -DGKO_COMPILING_OMP -DGKO_DEVICE_NAMESPACE=omp -Dginkgo_omp_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -fopenmp -MD -MT omp/CMakeFiles/ginkgo_omp.dir/__/common/unified/solver/common_gmres_kernels.cpp.o -MF omp/CMakeFiles/ginkgo_omp.dir/__/common/unified/solver/common_gmres_kernels.cpp.o.d -o omp/CMakeFiles/ginkgo_omp.dir/__/common/unified/solver/common_gmres_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/common/unified/solver/common_gmres_kernels.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres_kernels.hpp:17,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/common/unified/solver/common_gmres_kernels.cpp:10:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
cc1plus: some warnings being treated as errors
[4/51] /usr/bin/x86_64-pc-linux-gnu-g++ -DGKO_COMPILING_OMP -DGKO_DEVICE_NAMESPACE=omp -Dginkgo_omp_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -fopenmp -MD -MT omp/CMakeFiles/ginkgo_omp.dir/preconditioner/jacobi_kernels.cpp.o -MF omp/CMakeFiles/ginkgo_omp.dir/preconditioner/jacobi_kernels.cpp.o.d -o omp/CMakeFiles/ginkgo_omp.dir/preconditioner/jacobi_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp
FAILED: omp/CMakeFiles/ginkgo_omp.dir/preconditioner/jacobi_kernels.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -DGKO_COMPILING_OMP -DGKO_DEVICE_NAMESPACE=omp -Dginkgo_omp_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -fopenmp -MD -MT omp/CMakeFiles/ginkgo_omp.dir/preconditioner/jacobi_kernels.cpp.o -MF omp/CMakeFiles/ginkgo_omp.dir/preconditioner/jacobi_kernels.cpp.o.d -o omp/CMakeFiles/ginkgo_omp.dir/preconditioner/jacobi_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:21:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In instantiation of ‘gko::truncated<FloatType, NumComponents, ComponentId>::operator float_type() const [with FloatType = float; long unsigned int NumComponents = 2; long unsigned int ComponentId = 0; float_type = float]’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include/ginkgo/core/base/math.hpp:597:49:   required from ‘R gko::default_converter<S, R>::operator()(S) [with S = gko::truncated<float, 2, 0>; R = float]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:473:38:   required from ‘void gko::kernels::omp::jacobi::{anonymous}::apply_block(gko::size_type, gko::size_type, const BlockValueType*, gko::size_type, ValueType, const ValueType*, gko::size_type, ValueType, ValueType*, gko::size_type, ValueConverter) [with ValueType = float; BlockValueType = gko::truncated<float, 2, 0>; ValueConverter = gko::default_converter<gko::truncated<float, 2, 0>, float>; gko::size_type = long unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:506:9:   required from ‘void gko::kernels::omp::jacobi::apply(std::shared_ptr<const gko::OmpExecutor>, gko::size_type, gko::uint32, const gko::preconditioner::block_interleaved_storage_scheme<IndexType>&, const gko::array<gko::precision_reduction>&, const gko::array<IndexType>&, const gko::array<ValueType>&, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, gko::matrix::Dense<ValueType>*) [with ValueType = float; IndexType = int; gko::size_type = long unsigned int; gko::uint32 = unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:517:1:   required from here
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:437:52: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  437 |         return reinterpret_cast<const float_type&>(bits);
      |                                                    ^~~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In instantiation of ‘gko::truncated<FloatType, NumComponents, ComponentId>::operator float_type() const [with FloatType = double; long unsigned int NumComponents = 2; long unsigned int ComponentId = 0; float_type = double]’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include/ginkgo/core/base/math.hpp:597:49:   required from ‘R gko::default_converter<S, R>::operator()(S) [with S = gko::truncated<double, 2, 0>; R = double]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:473:38:   required from ‘void gko::kernels::omp::jacobi::{anonymous}::apply_block(gko::size_type, gko::size_type, const BlockValueType*, gko::size_type, ValueType, const ValueType*, gko::size_type, ValueType, ValueType*, gko::size_type, ValueConverter) [with ValueType = double; BlockValueType = gko::truncated<double, 2, 0>; ValueConverter = gko::default_converter<gko::truncated<double, 2, 0>, double>; gko::size_type = long unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:506:9:   required from ‘void gko::kernels::omp::jacobi::apply(std::shared_ptr<const gko::OmpExecutor>, gko::size_type, gko::uint32, const gko::preconditioner::block_interleaved_storage_scheme<IndexType>&, const gko::array<gko::precision_reduction>&, const gko::array<IndexType>&, const gko::array<ValueType>&, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, gko::matrix::Dense<ValueType>*) [with ValueType = double; IndexType = int; gko::size_type = long unsigned int; gko::uint32 = unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:517:1:   required from here
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:437:52: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In instantiation of ‘gko::truncated<FloatType, NumComponents, ComponentId>::operator float_type() const [with FloatType = double; long unsigned int NumComponents = 4; long unsigned int ComponentId = 0; float_type = double]’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include/ginkgo/core/base/math.hpp:597:49:   required from ‘R gko::default_converter<S, R>::operator()(S) [with S = gko::truncated<double, 4, 0>; R = double]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:473:38:   required from ‘void gko::kernels::omp::jacobi::{anonymous}::apply_block(gko::size_type, gko::size_type, const BlockValueType*, gko::size_type, ValueType, const ValueType*, gko::size_type, ValueType, ValueType*, gko::size_type, ValueConverter) [with ValueType = double; BlockValueType = gko::truncated<double, 4, 0>; ValueConverter = gko::default_converter<gko::truncated<double, 4, 0>, double>; gko::size_type = long unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:506:9:   required from ‘void gko::kernels::omp::jacobi::apply(std::shared_ptr<const gko::OmpExecutor>, gko::size_type, gko::uint32, const gko::preconditioner::block_interleaved_storage_scheme<IndexType>&, const gko::array<gko::precision_reduction>&, const gko::array<IndexType>&, const gko::array<ValueType>&, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, gko::matrix::Dense<ValueType>*) [with ValueType = double; IndexType = int; gko::size_type = long unsigned int; gko::uint32 = unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/preconditioner/jacobi_kernels.cpp:517:1:   required from here
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:437:52: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
cc1plus: some warnings being treated as errors
[5/51] /usr/bin/x86_64-pc-linux-gnu-g++ -DGKO_COMPILING_OMP -DGKO_DEVICE_NAMESPACE=omp -Dginkgo_omp_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -fopenmp -MD -MT omp/CMakeFiles/ginkgo_omp.dir/solver/cb_gmres_kernels.cpp.o -MF omp/CMakeFiles/ginkgo_omp.dir/solver/cb_gmres_kernels.cpp.o.d -o omp/CMakeFiles/ginkgo_omp.dir/solver/cb_gmres_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/solver/cb_gmres_kernels.cpp
FAILED: omp/CMakeFiles/ginkgo_omp.dir/solver/cb_gmres_kernels.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -DGKO_COMPILING_OMP -DGKO_DEVICE_NAMESPACE=omp -Dginkgo_omp_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -fopenmp -MD -MT omp/CMakeFiles/ginkgo_omp.dir/solver/cb_gmres_kernels.cpp.o -MF omp/CMakeFiles/ginkgo_omp.dir/solver/cb_gmres_kernels.cpp.o.d -o omp/CMakeFiles/ginkgo_omp.dir/solver/cb_gmres_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/solver/cb_gmres_kernels.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres_kernels.hpp:17,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/omp/solver/cb_gmres_kernels.cpp:5:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
cc1plus: some warnings being treated as errors
[6/51] /usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_reference_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT reference/CMakeFiles/ginkgo_reference.dir/preconditioner/jacobi_kernels.cpp.o -MF reference/CMakeFiles/ginkgo_reference.dir/preconditioner/jacobi_kernels.cpp.o.d -o reference/CMakeFiles/ginkgo_reference.dir/preconditioner/jacobi_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp
FAILED: reference/CMakeFiles/ginkgo_reference.dir/preconditioner/jacobi_kernels.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_reference_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT reference/CMakeFiles/ginkgo_reference.dir/preconditioner/jacobi_kernels.cpp.o -MF reference/CMakeFiles/ginkgo_reference.dir/preconditioner/jacobi_kernels.cpp.o.d -o reference/CMakeFiles/ginkgo_reference.dir/preconditioner/jacobi_kernels.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:18:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In instantiation of ‘gko::truncated<FloatType, NumComponents, ComponentId>::operator float_type() const [with FloatType = float; long unsigned int NumComponents = 2; long unsigned int ComponentId = 0; float_type = float]’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include/ginkgo/core/base/math.hpp:597:49:   required from ‘R gko::default_converter<S, R>::operator()(S) [with S = gko::truncated<float, 2, 0>; R = float]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:443:38:   required from ‘void gko::kernels::reference::jacobi::{anonymous}::apply_block(gko::size_type, gko::size_type, const BlockValueType*, gko::size_type, ValueType, const ValueType*, gko::size_type, ValueType, ValueType*, gko::size_type, ValueConverter) [with ValueType = float; BlockValueType = gko::truncated<float, 2, 0>; ValueConverter = gko::default_converter<gko::truncated<float, 2, 0>, float>; gko::size_type = long unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:486:9:   required from ‘void gko::kernels::reference::jacobi::apply(std::shared_ptr<const gko::ReferenceExecutor>, gko::size_type, gko::uint32, const gko::preconditioner::block_interleaved_storage_scheme<IndexType>&, const gko::array<gko::precision_reduction>&, const gko::array<IndexType>&, const gko::array<ValueType>&, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, gko::matrix::Dense<ValueType>*) [with ValueType = float; IndexType = int; gko::size_type = long unsigned int; gko::uint32 = unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:497:1:   required from here
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:437:52: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  437 |         return reinterpret_cast<const float_type&>(bits);
      |                                                    ^~~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In instantiation of ‘gko::truncated<FloatType, NumComponents, ComponentId>::operator float_type() const [with FloatType = double; long unsigned int NumComponents = 2; long unsigned int ComponentId = 0; float_type = double]’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include/ginkgo/core/base/math.hpp:597:49:   required from ‘R gko::default_converter<S, R>::operator()(S) [with S = gko::truncated<double, 2, 0>; R = double]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:443:38:   required from ‘void gko::kernels::reference::jacobi::{anonymous}::apply_block(gko::size_type, gko::size_type, const BlockValueType*, gko::size_type, ValueType, const ValueType*, gko::size_type, ValueType, ValueType*, gko::size_type, ValueConverter) [with ValueType = double; BlockValueType = gko::truncated<double, 2, 0>; ValueConverter = gko::default_converter<gko::truncated<double, 2, 0>, double>; gko::size_type = long unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:486:9:   required from ‘void gko::kernels::reference::jacobi::apply(std::shared_ptr<const gko::ReferenceExecutor>, gko::size_type, gko::uint32, const gko::preconditioner::block_interleaved_storage_scheme<IndexType>&, const gko::array<gko::precision_reduction>&, const gko::array<IndexType>&, const gko::array<ValueType>&, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, gko::matrix::Dense<ValueType>*) [with ValueType = double; IndexType = int; gko::size_type = long unsigned int; gko::uint32 = unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:497:1:   required from here
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:437:52: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In instantiation of ‘gko::truncated<FloatType, NumComponents, ComponentId>::operator float_type() const [with FloatType = double; long unsigned int NumComponents = 4; long unsigned int ComponentId = 0; float_type = double]’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include/ginkgo/core/base/math.hpp:597:49:   required from ‘R gko::default_converter<S, R>::operator()(S) [with S = gko::truncated<double, 4, 0>; R = double]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:443:38:   required from ‘void gko::kernels::reference::jacobi::{anonymous}::apply_block(gko::size_type, gko::size_type, const BlockValueType*, gko::size_type, ValueType, const ValueType*, gko::size_type, ValueType, ValueType*, gko::size_type, ValueConverter) [with ValueType = double; BlockValueType = gko::truncated<double, 4, 0>; ValueConverter = gko::default_converter<gko::truncated<double, 4, 0>, double>; gko::size_type = long unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:486:9:   required from ‘void gko::kernels::reference::jacobi::apply(std::shared_ptr<const gko::ReferenceExecutor>, gko::size_type, gko::uint32, const gko::preconditioner::block_interleaved_storage_scheme<IndexType>&, const gko::array<gko::precision_reduction>&, const gko::array<IndexType>&, const gko::array<ValueType>&, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, const gko::matrix::Dense<ValueType>*, gko::matrix::Dense<ValueType>*) [with ValueType = double; IndexType = int; gko::size_type = long unsigned int; gko::uint32 = unsigned int]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/reference/preconditioner/jacobi_kernels.cpp:497:1:   required from here
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:437:52: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
cc1plus: some warnings being treated as errors
[7/51] /usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_dpcpp_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/device_hooks/CMakeFiles/ginkgo_dpcpp.dir/dpcpp_hooks.cpp.o -MF core/device_hooks/CMakeFiles/ginkgo_dpcpp.dir/dpcpp_hooks.cpp.o.d -o core/device_hooks/CMakeFiles/ginkgo_dpcpp.dir/dpcpp_hooks.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/dpcpp_hooks.cpp
FAILED: core/device_hooks/CMakeFiles/ginkgo_dpcpp.dir/dpcpp_hooks.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_dpcpp_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/device_hooks/CMakeFiles/ginkgo_dpcpp.dir/dpcpp_hooks.cpp.o -MF core/device_hooks/CMakeFiles/ginkgo_dpcpp.dir/dpcpp_hooks.cpp.o.d -o core/device_hooks/CMakeFiles/ginkgo_dpcpp.dir/dpcpp_hooks.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/dpcpp_hooks.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres_kernels.hpp:17,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/common_kernels.inc.cpp:56,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/dpcpp_hooks.cpp:156:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
cc1plus: some warnings being treated as errors
[8/51] /usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_cuda_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/device_hooks/CMakeFiles/ginkgo_cuda.dir/cuda_hooks.cpp.o -MF core/device_hooks/CMakeFiles/ginkgo_cuda.dir/cuda_hooks.cpp.o.d -o core/device_hooks/CMakeFiles/ginkgo_cuda.dir/cuda_hooks.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/cuda_hooks.cpp
FAILED: core/device_hooks/CMakeFiles/ginkgo_cuda.dir/cuda_hooks.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_cuda_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/device_hooks/CMakeFiles/ginkgo_cuda.dir/cuda_hooks.cpp.o -MF core/device_hooks/CMakeFiles/ginkgo_cuda.dir/cuda_hooks.cpp.o.d -o core/device_hooks/CMakeFiles/ginkgo_cuda.dir/cuda_hooks.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/cuda_hooks.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres_kernels.hpp:17,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/common_kernels.inc.cpp:56,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/cuda_hooks.cpp:263:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
cc1plus: some warnings being treated as errors
[9/51] /usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_hip_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/device_hooks/CMakeFiles/ginkgo_hip.dir/hip_hooks.cpp.o -MF core/device_hooks/CMakeFiles/ginkgo_hip.dir/hip_hooks.cpp.o.d -o core/device_hooks/CMakeFiles/ginkgo_hip.dir/hip_hooks.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/hip_hooks.cpp
FAILED: core/device_hooks/CMakeFiles/ginkgo_hip.dir/hip_hooks.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_hip_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/device_hooks/CMakeFiles/ginkgo_hip.dir/hip_hooks.cpp.o -MF core/device_hooks/CMakeFiles/ginkgo_hip.dir/hip_hooks.cpp.o.d -o core/device_hooks/CMakeFiles/ginkgo_hip.dir/hip_hooks.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/hip_hooks.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres_kernels.hpp:17,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/common_kernels.inc.cpp:56,
                 from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/device_hooks/hip_hooks.cpp:258:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
cc1plus: some warnings being treated as errors
[10/51] /usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/CMakeFiles/ginkgo.dir/solver/cb_gmres.cpp.o -MF core/CMakeFiles/ginkgo.dir/solver/cb_gmres.cpp.o.d -o core/CMakeFiles/ginkgo.dir/solver/cb_gmres.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres.cpp
FAILED: core/CMakeFiles/ginkgo.dir/solver/cb_gmres.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/CMakeFiles/ginkgo.dir/solver/cb_gmres.cpp.o -MF core/CMakeFiles/ginkgo.dir/solver/cb_gmres.cpp.o.d -o core/CMakeFiles/ginkgo.dir/solver/cb_gmres.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/solver/cb_gmres.cpp:19:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
cc1plus: some warnings being treated as errors
[11/51] /usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/CMakeFiles/ginkgo.dir/preconditioner/jacobi.cpp.o -MF core/CMakeFiles/ginkgo.dir/preconditioner/jacobi.cpp.o.d -o core/CMakeFiles/ginkgo.dir/preconditioner/jacobi.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/preconditioner/jacobi.cpp
FAILED: core/CMakeFiles/ginkgo.dir/preconditioner/jacobi.cpp.o 
/usr/bin/x86_64-pc-linux-gnu-g++ -Dginkgo_EXPORTS -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999_build/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/include -I/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999  -pipe -march=native -fstack-protector-all -O2 -fdiagnostics-color=always -frecord-gcc-switches -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -fPIC -MD -MT core/CMakeFiles/ginkgo.dir/preconditioner/jacobi.cpp.o -MF core/CMakeFiles/ginkgo.dir/preconditioner/jacobi.cpp.o.d -o core/CMakeFiles/ginkgo.dir/preconditioner/jacobi.cpp.o -c /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/preconditioner/jacobi.cpp
In file included from /var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/preconditioner/jacobi.cpp:20:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In constructor ‘gko::half::half(gko::float32)’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:291:60: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  291 |         data_ = float2half(reinterpret_cast<const uint32&>(val));
      |                                                            ^~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In member function ‘gko::half::operator gko::float32() const’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:304:49: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  304 |         return reinterpret_cast<const float32&>(bits);
      |                                                 ^~~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In instantiation of ‘gko::truncated<FloatType, NumComponents, ComponentId>::operator float_type() const [with FloatType = float; long unsigned int NumComponents = 2; long unsigned int ComponentId = 0; float_type = float]’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/preconditioner/jacobi.cpp:236:13:   required from ‘void gko::preconditioner::Jacobi<ValueType, IndexType>::write(mat_data&) const [with ValueType = float; IndexType = int; mat_data = gko::matrix_data<float, int>]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/preconditioner/jacobi.cpp:377:1:   required from here
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:437:52: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
  437 |         return reinterpret_cast<const float_type&>(bits);
      |                                                    ^~~~
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In instantiation of ‘gko::truncated<FloatType, NumComponents, ComponentId>::operator float_type() const [with FloatType = double; long unsigned int NumComponents = 2; long unsigned int ComponentId = 0; float_type = double]’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/preconditioner/jacobi.cpp:236:13:   required from ‘void gko::preconditioner::Jacobi<ValueType, IndexType>::write(mat_data&) const [with ValueType = double; IndexType = int; mat_data = gko::matrix_data<double, int>]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/preconditioner/jacobi.cpp:377:1:   required from here
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:437:52: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp: In instantiation of ‘gko::truncated<FloatType, NumComponents, ComponentId>::operator float_type() const [with FloatType = double; long unsigned int NumComponents = 4; long unsigned int ComponentId = 0; float_type = double]’:
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/preconditioner/jacobi.cpp:236:13:   required from ‘void gko::preconditioner::Jacobi<ValueType, IndexType>::write(mat_data&) const [with ValueType = double; IndexType = int; mat_data = gko::matrix_data<double, int>]’
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/preconditioner/jacobi.cpp:377:1:   required from here
/var/tmp/portage/sci-libs/ginkgo-9999/work/ginkgo-9999/core/base/extended_float.hpp:437:52: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
cc1plus: some warnings being treated as errors
ninja: build stopped: cannot make progress due to previous errors.

Originally reported downstream: https://bugs.gentoo.org/862705 Full build log: build.log