[llvm] [AMDGPU] New AMDGPUInsertSingleUseVDST pass (PR #72388)

[Carl Ritson via llvm-commits]

https://github.com/perlfu approved this pull request.

LGTM - but should fix illegal copies from VGPR to SGPR in tests

Thanks for the updated tests.
I think the clarification around f16 behaviour is important.

https://github.com/llvm/llvm-project/pull/72388