[llvm] [VPlan] First step towards VPlan cost modeling (LegacyCM in CostCtx) (PR #92555)

[via llvm-commits]

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@@ -7396,6 +7397,122 @@ LoopVectorizationPlanner::plan(ElementCount UserVF, unsigned UserIC) {
   return VF;
 }
 
+InstructionCost VPCostContext::getLegacyCost(Instruction *UI, ElementCount VF) {
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ayalz wrote:

const?

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