[llvm] [LV] Add support for widening loads/stores to a VF multiple (PR #217670)

[Benjamin Maxwell via llvm-commits]

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@@ -5754,6 +5754,8 @@ DenseMap<const SCEV *, Value *> LoopVectorizationPlanner::executePlan(
                  *PSE.getSE(), TTI, Config.CostKind, BestVF, BestUF);
   // TODO: Move to VPlan transform stage once the transition to the VPlan-based
   // cost model is complete for better cost estimates.
+  RUN_VPLAN_PASS(VPlanTransforms::scaleMemoryAccessesByUF, BestVPlan, BestVF,
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MacDue wrote:

I've split the hook into `get[Maximum|Preferred]VFMultipleForMemoryOp` hooks, so the former can be used to skip the transform when it's one. 

https://github.com/llvm/llvm-project/pull/217670