[llvm] [LoopVectorize] Make needsExtract notice scalarized instructions (PR #119720)

[David Sherwood via llvm-commits]

https://github.com/david-arm approved this pull request.

LGTM! I think this change seems sensible. I had a look at a few examples where we would have a Scalarize widening decision for the instruction and the outcome would indeed have led to a scalarised load where an extract is not needed. For example, the second load in function replicate_operands_in_with_operands_in_minbws in Transforms/LoopVectorize/AArch64/deterministic-type-shrinkage.ll.

https://github.com/llvm/llvm-project/pull/119720