[llvm] [VPlan] Move initial skeleton construction earlier (NFC). (PR #150848)

[Ramkumar Ramachandra via llvm-commits]

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@@ -8918,10 +8920,13 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlan(VFRange &Range) {
   assert(EnableVPlanNativePath && "VPlan-native path is not enabled.");
 
   auto Plan = VPlanTransforms::buildPlainCFG(OrigLoop, *LI);
-  VPlanTransforms::prepareForVectorization(
-      *Plan, Legal->getWidestInductionType(), PSE, true, false, OrigLoop,
-      getDebugLocFromInstOrOperands(Legal->getPrimaryInduction()), false,
-      Range);
+
+  VPlanTransforms::addInitialSkeleton(
+      *Plan, Legal->getWidestInductionType(),
+      getDebugLocFromInstOrOperands(Legal->getPrimaryInduction()), PSE,
+      OrigLoop);
+  VPlanTransforms::handleEarlyExitsAndAddMiddleCheck(*Plan, true, false, false,
+                                                     Range);
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artagnon wrote:

Inline comments annotating the true/false args?

https://github.com/llvm/llvm-project/pull/150848