[llvm] [LoopVectorize] Improve Vectorization of Low Trip Count Loops (PR #195823)

[Sander de Smalen via llvm-commits]

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sdesmalen-arm wrote:

Just a general comment that to me it makes little sense to me that the LV accepts a non-power-of-2 VF when passed by `-force` option, but otherwise ignores it as a hint because it's not a valid hint. @fhahn is that intentional?

https://github.com/llvm/llvm-project/pull/195823