[flang-commits] [mlir] [flang] [WIP] Delayed privatization. (PR #79862)

[Kareem Ergawy via flang-commits]

ergawy wrote:

Thanks again for taking a look here. Since I see no objections to the taken approach (I hope I am not delusional :D), here is my plan:
1. In this PR: try to get the pipeline to be green and make sure that no lit tests fail because of the introduced changes.
2. In this PR: handle the remaining in of you comments so that you do not have to spend effort on them in later separate PRs.
3. This PR will **not** be merged since it is getting quite large. Instead I will split it into a number of PRs as explained in following points.
4. PR 1: a NFC PR to copy the refactoring of `genOpWithBody` introduced here. This will introduce the `genRegionEntryCB` callback and use it for worksharing loop ops.
5. PR 2: copy the `omp.private` op along with a roundtripping lit test to test parsing, printing, and verification.
6. PR 3: copy the extensions in `omp.parallel` op (i.e. adding the `private` clause) along with a roundtripping lit test as well.
7. PR 4: copy the changes introduced in the `OpenMPToLLVM.cpp` conversion pattern: `RegionOpConversion`.
8. PR 5: copy the changes introduced in `OpenMPToLLVMIRTranslation.cpp`: the `PrivCB` and `prepareOmpParallel`.
9. PR 6: copy the changes needed for creating the `omp.private` ops and modifying the creation of the `omp.parallel` op to use the new clause. These are most of the changes in `DataSharingProcessor` and `genParallelOp`.

Please let me know if you disagree with anything :).

https://github.com/llvm/llvm-project/pull/79862