CUDA warning #20013-D when there is not the flag --expt-relaxed-constexpr

[xq114]

When I try to include ginkgo in my CUDA .cu source files, I get the warning from the compiler:

include\ginkgo/core/preconditioner/jacobi.hpp(71): warning #20013-D: calling a constexpr __host__ function("one") from a __host__ __device__ function("get_group_size") is not allowed. The experimental flag '--expt-relaxed-constexpr' can be used to allow this.
          return one<IndexType>() << group_power;
                 ^
          detected during:
            instantiation of "IndexType gko::preconditioner::block_interleaved_storage_scheme<IndexType>::get_group_size() const noexcept 
[with IndexType=vl::idx_t]" at line 91
            instantiation of "gko::size_type gko::preconditioner::block_interleaved_storage_scheme<IndexType>::compute_storage_space(gko::size_type) const noexcept [with IndexType=vl::idx_t]" at line 557
            instantiation of "gko::preconditioner::Jacobi<ValueType, IndexType>::Jacobi(const gko::preconditioner::Jacobi<ValueType, IndexType>::Factory *, std::shared_ptr<const gko::LinOp>) [with ValueType=float, IndexType=vl::idx_t]" at line 188 of include\ginkgo/core/base/abstract_factory.hpp
            instantiation of "std::unique_ptr<gko::EnableDefaultFactory<ConcreteFactory, ProductType, ParametersType, PolymorphicBase>::abstract_product_type, std::default_delete<gko::EnableDefaultFactory<ConcreteFactory, ProductType, ParametersType, PolymorphicBase>::abstract_product_type>> gko::EnableDefaultFactory<ConcreteFactory, ProductType, ParametersType, PolymorphicBase>::generate_impl(gko::EnableDefaultFactory<ConcreteFactory, ProductType, ParametersType, PolymorphicBase>::components_type) const [with ConcreteFactory=gko::preconditioner::Jacobi<float, vl::idx_t>::Factory, ProductType=gko::preconditioner::Jacobi<float, vl::idx_t>, ParametersType=gko::preconditioner::Jacobi<float, vl::idx_t>::parameters_type, PolymorphicBase=gko::LinOpFactory]" at line 501

It seems one is not marked __host__ __device__ or GKO_ATTRIBUTE.

System Info: Windows 10, CUDA 12.5, MSVC 17.12.4

[MarcelKoch]

The issue is caused by some inconsistencies on how we define device callable functions. I think it's safe to ignore the warning, until we will resolve this issue.