[llvm] [VPlan] First step towards VPlan cost modeling. (PR #67934)

[via llvm-commits]

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@@ -3182,6 +3198,10 @@ class VPlan {
     return any_of(VFs, [](ElementCount VF) { return VF.isScalable(); });
   }
 
+  iterator_range<SmallSetVector<ElementCount, 2>::iterator> vectorFactors() {
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ayalz wrote:

const?
getVectorFactors?

https://github.com/llvm/llvm-project/pull/67934