[llvm] [VPlan] Connect Entry to scalar preheader during initial construction. (PR #140132)

[via llvm-commits]

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@@ -8070,7 +8064,8 @@ EpilogueVectorizerMainLoop::emitIterationCountCheck(BasicBlock *Bypass,
     setBranchWeights(BI, MinItersBypassWeights, /*IsExpected=*/false);
   ReplaceInstWithInst(TCCheckBlock->getTerminator(), &BI);
 
-  introduceCheckBlockInVPlan(TCCheckBlock);
+  if (!ForEpilogue)
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ayalz wrote:

```suggestion
  // Worth explaining?
  if (!ForEpilogue)
```

https://github.com/llvm/llvm-project/pull/140132