[Openmp-commits] [llvm] [openmp] [OpenMP] Change build of OpenMP device runtime to be a separate runtime (PR #136729)

[Joseph Huber via Openmp-commits]

jhuber6 wrote:

> To make one thing clear early on: **Standalone**, this only introduces cost. There is no tangible benefit from this PR, but a CMake change that will break people. If this is done after other reorganizations have happened, e.g., a generic device RTL is created, this might change, though I am not sure about tangible benefits then either.

I'm assuming you mean that moving to `openmp/` only introduces cost? This PR has a very tangible benefit of decoupling the offload runtime with the GPU runtime builds.
 
> Alternative Proposal:
> 
> ```
> offload/DeviceRTL/generic
> offload/DeviceRTL/openmp
> offload/DeviceRTL/openacc
> offload/DeviceRTL/sycl
> offload/DeviceRTL/cuda
> ...
> ```
> 
> Now `DeviceRTL.openmp.a` lives in .../openmp/ and we can guard building it with "OPENMP_IS_ENABLED".
> 

As I understand, we already have a pretty strong tendency toward the former. We have right now `flang-rt`, `compiler-rt`, `libclc`, and `openmp`. If this is the direction that LLVM wants then surely we could make `language-runtimes/flang/` etc in a similar fashion? I think it's more straightforward that the OpenMP language has its runtime in the OpenMP project.


https://github.com/llvm/llvm-project/pull/136729