[flang] [llvm] [mlir] [OpenMP][flang] Lowering of OpenMP custom reductions to MLIR (PR #168417)

[Tom Eccles via llvm-commits]

https://github.com/tblah commented:

Thank you for contributing this. The overall design looks good to me but I think we need to do more to correctly init and de-init derived types.

https://github.com/llvm/llvm-project/pull/168417