[llvm] [polly] [DA] Add batch delinearization support for improved precision (PR #170519)

[Sebastian Pop via llvm-commits]

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sebpop wrote:

@alexey-bataev asked to "Use SmallDenseMap, it improves compile time", and thus I also impacted this change to Polly from where I got the caching mechanism.

https://github.com/llvm/llvm-project/pull/170519