[llvm] [VPlan] Hook IR blocks into VPlan during skeleton creation (NFC) (PR #114292)

[Florian Hahn via llvm-commits]

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@@ -2426,6 +2426,26 @@ InnerLoopVectorizer::getOrCreateVectorTripCount(BasicBlock *InsertBlock) {
   return VectorTripCount;
 }
 
+static void connectScalarPreheaderInVPlan(VPlan &Plan) {
+  VPBlockBase *VectorPH = Plan.getVectorPreheader();
+  VPBlockBase *ScalarPH = Plan.getScalarPreheader();
+  VPBlockBase *PredVPB = VectorPH->getSinglePredecessor();
+  VPBlockUtils::disconnectBlocks(Plan.getEntry(), VectorPH);
+  VPBlockUtils::connectBlocks(PredVPB, ScalarPH);
+  VPBlockUtils::connectBlocks(PredVPB, VectorPH);
+}
+
+static void connectCheckBlockInVPlan(VPlan &Plan, BasicBlock *CheckIRBB) {
+  VPBlockBase *ScalarPH = Plan.getScalarPreheader();
+  VPBlockBase *VectorPH = Plan.getVectorPreheader();
+  VPBlockBase *PredVPB = VectorPH->getSinglePredecessor();
+  VPBlockUtils::disconnectBlocks(PredVPB, VectorPH);
+  VPIRBasicBlock *CheckVPIRBB = VPIRBasicBlock::fromBasicBlock(CheckIRBB);
+  VPBlockUtils::connectBlocks(PredVPB, CheckVPIRBB);
+  VPBlockUtils::connectBlocks(CheckVPIRBB, ScalarPH);
+  VPBlockUtils::connectBlocks(CheckVPIRBB, VectorPH);
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fhahn wrote:

Updated for now to use the new connect variant but left the everything else as is for now. Will check if there are other places where the new helper could be used.

https://github.com/llvm/llvm-project/pull/114292