[clang] [llvm] [clang][OpenMP] Improve loop structure for distributed loops (PR #201670)

[Robert Imschweiler via cfe-commits]

ro-i wrote:

> No, not yet. Do you have interesting snippets you'd like to see results for?

Hm, I let AI come up with some tests and created some experimental benchmarks for them: https://github.com/ro-i/xteam-test/blob/main/src/xteam_misc.cpp

For these, the changed loop structure seems to be not beneficial at all. Let me find out why

https://github.com/llvm/llvm-project/pull/201670