2020 06 15 sync

Agenda

• Opens

• Patches in review for llorg:

  • https://reviews.llvm.org/D74387 - [SYCL] Do not diagnose use of __float128
  • https://reviews.llvm.org/D81641 - [SYCL] Implement thread-local storage restriction
  • https://reviews.llvm.org/D80932 - [SYCL] Make default address space a superset of OpenCL address spaces

• GitHub issues/PRs

  • https://github.com/intel/llvm/issues/1799#issuecomment-637395726 - half implementation: __fp16 vs _Float16.

• Back-burner

  • https://reviews.llvm.org/D71016 - [SYCL] Implement OpenCL kernel function generation
  • https://reviews.llvm.org/D77220 - [SYCL] Enable OpenCL types required for implementing the SYCL headers.

Meeting notes

Participants: Alexey Bader (Intel), Mariya Podchischaeva (Intel), Ronan Keryell (Xilinx), Victor Lomuller (Codeplay), Hal Finkel (ANL)

• Opens

  • No.

• Patches in review for llorg:

  • https://reviews.llvm.org/D80932 - [SYCL] Make default address space a superset of OpenCL address spaces
    • Ronan: How are we going to handle all the questions from Anastasia?
    • Victor: Should we get Anastasia involved into SYCL development?
    • Alexey: I'm going to write an RFC to cfe mailing list and address the questions there.
    • Victor: We should draw parallel to CUDA comparing the programming model. Other single source programming models have the same problems.
    • Victor: Here we trying to pull some OpenCL concepts in to single source.
    • Victor: CUDA doesn't resolve any address spaces - everything generic.
    • Victor: SYCL approach is somewhere in between - that's why we need to make changes.
    • Victor: New version of the spec will help by generalizing back-ends.
  • https://reviews.llvm.org/D74387 - [SYCL] Do not diagnose use of __float128
  • Done. Committed unified implementation for SYCL and OpenMP compilers.
  • https://reviews.llvm.org/D81641 - [SYCL] Implement thread-local storage restriction
  • Similar to previous case we need unify implementation to support multiple GPGPU programming models.
  • AR Mariya: to double check with Johannes whether we need to generalize the approach in the same patch.

• GitHub issues/PRs

  • https://github.com/intel/llvm/issues/1799#issuecomment-637395726 - half implementation: __fp16 vs _Float16.
    • Mariya: after my patch with diagnostics of __float128, some tests started failing.
    • Victor: CUDA target reported that it doesn't support half data type.
    • Victor: _Float16 is used for half data type implementation
    • Victor: NVIDIA supports half, but not for all operations.
    • Victor: if we use __fp16 for half, it should work everywhere even if the target doesn't support at HW level.
    • Victor: have a PR prototype for using __fp16 in half.

• Back-burner

  • https://reviews.llvm.org/D71016 - [SYCL] Implement OpenCL kernel function generation
    • Big open is how to handle OpenCL types in structures?
  • https://reviews.llvm.org/D77220 - [SYCL] Enable OpenCL types required for implementing the SYCL headers.