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

[via llvm-commits]

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@@ -855,9 +862,13 @@ VPlanPtr VPlan::createInitialVPlan(Type *InductionTy,
   VPIRBasicBlock *Entry =
       VPIRBasicBlock::fromBasicBlock(TheLoop->getLoopPreheader());
   VPBasicBlock *VecPreheader = new VPBasicBlock("vector.ph");
+  // Connect entry only to vector preheader initially. Edges to the scalar
+  // preheader will be inserted later, during skeleton creation when runtime
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ayalz wrote:

```suggestion
  // Connect entry only to vector preheader initially. Entry will also be connected to the scalar
  // preheader later, during skeleton creation when runtime
```

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