[SYCL][Devicelib] Implement cmath rintf wrapper with __spirv_ocl_rint

[wenju-he]

This PR is to support the use of std::rint in device code. Currently it
is resolved to rintf symbol. With this PR, the rintf symbol is resolved
by libdevice.

[npmiller]

LGTM, we could probably remove the NVPTX/AMDGCN specific path and use the __spirv_ocl_rint path for them as well, but we can look at that in a different patch.

[bader]

In general, there is no point in adding __device_lib_<func> fallback implementation to the devicelib for the functions which have corresponding __spirv_ocl_<func>. The whole idea behind __device_lib_ is to bypass adding SPIR-V extensions for C/C++ standard library functions. If SPIR-V instruction is already defined, we can implement corresponding C/C++ functions as wrappers in the headers.

[againull]

Could you add a test please.

[wenju-he]

If SPIR-V instruction is already defined, we can implement corresponding C/C++ functions as wrappers in the headers.

Could you point me to the wrapper that implements std::rint with __spirv_ocl_rint?

This PR is to support use of std::rint in device code. Currently it is resolved to rintf symbol. With this PR, rintf symbol is resolved by libdevice.

[jinge90]

If SPIR-V instruction is already defined, we can implement corresponding C/C++ functions as wrappers in the headers.

Could you point me to the wrapper that implements std::rint with __spirv_ocl_rint?

This PR is to support use of std::rint in device code. Currently it is resolved to rintf symbol. With this PR, rintf symbol is resolved by libdevice.

Hi, @bader and @wenju-he
If it is for support C++ std::rint, the header file is in user's system header which we can't modify. But we have decided to remove fallback devicelib, we can directly use __spirv_oc_rint in cmath_wrapper.cpp 'rintf' function.

[wenju-he]

the header file is in user's system header which we can't modify. But we have decided to remove fallback devicelib, we can directly use __spirv_oc_rint in cmath_wrapper.cpp 'rintf' function.

done, thanks.

[npmiller]

If SPIR-V instruction is already defined, we can implement corresponding C/C++ functions as wrappers in the headers.

Could you point me to the wrapper that implements std::rint with __spirv_ocl_rint?

This PR is to support use of std::rint in device code. Currently it is resolved to rintf symbol. With this PR, rintf symbol is resolved by libdevice.

It's not actually ready yet, but I've been working on that in #18706 which will address this rint issue once completed, but it needs more work and is currently only tested for CUDA/HIP. So I think it's fine to go ahead with this PR until the header solution is ready.

[wenju-he]

It's not actually ready yet, but I've been working on that in #18706 which will address this rint issue once completed, but it needs more work and is currently only tested for CUDA/HIP. So I think it's fine to go ahead with this PR until the header solution is ready.

thanks @npmiller, #18706 looks great.