[flang] [llvm] [flang] implement `split` for fortran 2023 (PR #161484)

[Peter Klausler via llvm-commits]

https://github.com/klausler requested changes to this pull request.

In Flang/docs/F202X.md there is a means of implementing `SPLIT` in terms of `SCAN`.  Perhaps you could make `SPLIT` faster than `SCAN`, but if not, a second implementation of the same algorithm is redundant; they should be combined, or `SPLIT` should be a wrapper around `SCAN`.

Documentation is missing in flang/docs/Intrinsics.md.

https://github.com/llvm/llvm-project/pull/161484