SYCL backend

[iwr-redmond]

It may be helpful to support SYCL in addition to the native CUDA and ROCm implementations. This may be as simple as some testing and documentation, although code changes for an additional backend are also entirely possible.

[ServeurpersoCom]

Hi @iwr-redmond, GGML already has a SYCL backend and our architecture is backend-agnostic, so it should work out of the box. To build:

Probably need a "source /opt/intel/oneapi/setvars.sh" ?

mkdir build && cd build
cmake .. -DGGML_SYCL=ON
cmake --build . --config Release -j $(nproc)

One thing to watch: the VAE uses two custom ops (ggml_snake and ggml_col2im_1d) that are implemented in the CUDA, Vulkan and CPU backends but not yet in SYCL. The scheduler will fall back to CPU for those, so the DiT and LM should run on SYCL but the VAE decode may be slower. If you can build and confirm everything runs, I can write the SYCL kernels for those two ops.

[iwr-redmond]

I use an RTX 4060 at the moment. Perhaps this FR can be left open so that a user with an Intel GPU can do the basic testing you need.