[llvm] [LoadStoreVectorizer] Postprocess and merge equivalence classes (PR #114501)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Using any fixed lookup depth can result into creation of multiple equivalence classes that only differ by 1-level indirection bases.

The test IR doesn't look canonical / optimal. Other passes are expected to have rewritten the addressing expressions to be a simpler form. If I run your examples through -O3, it mostly vectorizes with some quirks:

1. have to hackily avoid a memset that forms
2. Ends up with a scalar store + a 7x vector store 




https://github.com/llvm/llvm-project/pull/114501