[llvm] [VectorCombine] New folding pattern for extract/binop/shuffle chains (PR #145232)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon commented:

This still feels like its a lot more complicated than necessary - e.g. if we compare to SelectionDAG::matchBinOpReduction

https://github.com/llvm/llvm-project/pull/145232