[llvm] [DependenceAnalysis] Extending SIV to handle fusable loops (PR #128782)

[via llvm-commits]

amehsan wrote:

> So, at the very least, I personally think it would be better to insert an assertion like `assert(Dep->getFusableLevel() == 0)` in every place where DA is used to prevent any accidents in the future.

If you think about common customers of DA, whether in llvm or other compilers (loop interchange, loop distribution, loop vectorization) chances of accidentally passing two statements from two different loops to  DA is very low. Pretty much any user of DA needs to deal with enough details, that makes such mistakes low probability. But again I don't have objections if you think that is helpful.

Right now I skipped the first part of your comment about `isConsistent`. Will check it later. 

Thank you very much for taking the time to review and letting us know your opinion.

https://github.com/llvm/llvm-project/pull/128782