llvm-project

21622397 - [mlir][OpenMP] Translate explicit task in_reduction (#202611)

[mlir][OpenMP] Translate explicit task in_reduction (#202611) Lower `in_reduction` on explicit `omp.task` operations to LLVM IR. Inside the outlined task body, obtain the executing thread's `gtid` and call `__kmpc_task_reduction_get_th_data` with a null descriptor and the original reduction variable address. This lets the runtime find the enclosing taskgroup reduction registration and return the per-task private reduction storage. The `in_reduction` block arguments are remapped to the returned private storage, so updates inside the explicit task body target the task-private reduction copy instead of the original shared variable. Unsupported cases remain guarded, including byref `in_reduction` and richer `declare_reduction` forms such as two-argument initializers, cleanup regions, and missing combiners.