[llvm] [LoopUtils] Fix metadata generated by makeFollowupLoopID (PR #131985)

[Michael Kruse via llvm-commits]

Meinersbur wrote:

Looks like the problem is here: https://github.com/llvm/llvm-project/blob/39ce99589b05ddd43e5c8b7f89ab5bbfda40d2ce/clang/lib/CodeGen/CGLoopInfo.cpp#L134

It should add the properties, not the generated LoopID (that would be used if the #pragma was not the followup of another #pragma). Considering that it might be necessary to merge multiple such followup properties (eg. both of `followup_all` and `followup_vectorized` should be added to the vectorized loop).

Considering that I wrote both sides, I obviously wasn't consistent myself. If you fix it, could you fix it for wall `followup_*`? Possibly the `create*Metadata` should only return a list of properties instead of an MDNode, with the MDNode only to be created when applying the properties to a Loop. However, the easier fix would probably be to extract the properties from the MDNode and append to the `followup_*` MDNode, with the returned MDNode becoming garbage-collected at some point.


https://github.com/llvm/llvm-project/pull/131985