[llvm] [VPlan] Build initial VPlan 0 using HCFGBuilder for inner loops. (NFC) (PR #124432)

[via llvm-commits]

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@@ -9229,6 +9230,10 @@ LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(VFRange &Range) {
                                             PSE, RequiresScalarEpilogueCheck,
                                             CM.foldTailByMasking(), OrigLoop);
 
+  // Build hierarchical CFG.
+  VPlanHCFGBuilder HCFGBuilder(OrigLoop, LI, *Plan);
+  HCFGBuilder.buildHierarchicalCFG();
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ayalz wrote:

Perhaps `VPlanHCFGBuilder::buildingHierarchicalCFG()` which creates initial VPBB's inside loop region ( via `PlainCFGBuilder::buildPlainCFG()`) should now be combined with `VPlan::createInitialVPlan()` which creates initial VPBB's elsewhere?
Can be done as follow-up.

https://github.com/llvm/llvm-project/pull/124432