[llvm] [VPlan] First step towards VPlan cost modeling. (PR #92555)

[via llvm-commits]

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@@ -920,6 +979,10 @@ void VPlan::execute(VPTransformState *State) {
          "DT not preserved correctly");
 }
 
+InstructionCost VPlan::cost(ElementCount VF, VPCostContext &Ctx) {
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ayalz wrote:

May be worth a note that only the loop region is measured, preheader and post exit recipes are neglected.

https://github.com/llvm/llvm-project/pull/92555