`FunctionPropertyMetaInfo` and `PropertyMetaInfo` are duplicated for every property

[againull]

Commit bba4f4d (#21738) introduced FunctionPropertyMetaInfo<T> as a separate parallel trait to the existing PropertyMetaInfo<T>, used by SYCL_EXT_ONEAPI_FUNCTION_PROPERTY on the lightweight free-function path. However, for every property that needs to work on both the property-list path and the free-function path, authors are now required to write two structurally identical specializations with the same name and value members.

Currently duplicated in free_function_kernel_properties.hpp:

• work_group_size_key
• work_group_size_hint_key
• sub_group_size_key
• max_work_group_size_key
• max_linear_work_group_size_key

And in grf_size_properties.hpp:

• grf_size_key / grf_size_automatic_key

[sarnex]

@koparasy Can you please provide some analysis? Thanks

[koparasy]

We were trying to reduce compile time of the "free_function_kernel_properties.hpp" header. That header used to pull in sycl/ext/oneapi/properties/properties.hpp. That is an expensive header in terms of compilation time. So any TU that just wanted to annotate a free-function kernel (work_group_size, nd_range_kernel) dragged in the full properties<...> list template + aspects.hpp + forward_progress.hpp. The lightweight approach skips that duplicates 'PropertyMetaInfo` all that.

I believe though, I should not have introduced a new MetaInfo I could had re-used the existing one without any additional compilation cost. I will need to check compile time about this, but I believe you are right.

[sarnex]

Thanks, looking forward to your results