[PATCH] D64935: [AMDGPU] Add llvm.amdgcn.softwqm intrinsic

[Nicolai Hähnle via Phabricator via llvm-commits]

nhaehnle added a comment.

Have you checked that this actually fixes the reported CTS failure?

IIRC the CTS failure was essentially due to a shader of the form:

  derivative calculation here
  subgroup operation here

The derivative calculation enables WQM, but then we may leave WQM again for the subgroup operations which is unexpected (since helper lanes are expected to participate). So softwqm needs to seed WQM requirements, but only if there is at least one hard wqm requirement in the shader.


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D64935/new/

https://reviews.llvm.org/D64935