[llvm] [Offload] Add support for riscv64 to host plugin (PR #115773)

[via llvm-commits]

joshua-arch1 wrote:

> > It seems that we still cannot use -fopenmp-target=riscv64-unknown-linux-gnu.
> 
> What's the issue?

I‘m running openmp_vv suite on riscv clang. It seems that tests with target offloading cannot pass, like https://github.com/OpenMP-Validation-and-Verification/OpenMP_VV/blob/master/tests/4.5/target/test_target_defaultmap.c.

If I add -fopenmp-targets=riscv64-unknown-linux-gnu, it will show unsupported.

https://github.com/llvm/llvm-project/pull/115773