[llvm] [Delinearization] Add function for fixed size array without relying on GEP (PR #145050)

[Ryotaro Kasuga via llvm-commits]

kasuga-fj wrote:

> Ok, sounds good, let me know if I can help somehow.

This approach would prevent us from entirely eliminating the calls to old function from DA (i.e., although the old function is unlikely to be invoked logically, we can’t eliminate the string `tryDelinearizeFixedSizeImpl` entirely from DependenceAnalysis.cpp). Therefore, it would be ideal to add tests to ensure the old function isn't invoked by default, though I'm not sure what the best method would be. Could you investigate this further, including whether such tests are actually necessary?

https://github.com/llvm/llvm-project/pull/145050