[llvm] [VPlan] Simplify live-ins early using SCEV. (PR #155304)

[Florian Hahn via llvm-commits]

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@@ -528,12 +529,30 @@ static void addInitialSkeleton(VPlan &Plan, Type *InductionTy, DebugLoc IVDL,
   createExtractsForLiveOuts(Plan, MiddleVPBB);
 }
 
+static void simplifyPlanWithSCEV(VPlan &Plan, ScalarEvolution &SE) {
+  auto SimplifyWithSCEV = [&](VPValue *VPV) -> VPValue * {
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fhahn wrote:

Updated to `GetSimplifiedLiveInViaSCEV`. I have a few follow-up patches the generalize this to beyond constants.

https://github.com/llvm/llvm-project/pull/155304