[llvm] [VPlan] Set branch weight metadata on middle term in VPlan (NFC) (PR #143035)

[via llvm-commits]

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@@ -7295,11 +7322,8 @@ DenseMap<const SCEV *, Value *> LoopVectorizationPlanner::executePlan(
 
   VPlanTransforms::convertToConcreteRecipes(BestVPlan,
                                             *Legal->getWidestInductionType());
-  // Retrieve and store the middle block before dissolving regions. Regions are
-  // dissolved after optimizing for VF and UF, which completely removes unneeded
-  // loop regions first.
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ayalz wrote:

This part of the comment explains the positioning of `dissolveLoopRegions()` below, so should be retained?
```
  // Regions are dissolved after optimizing for VF and UF, which completely removes unneeded
  // loop regions first.
```

https://github.com/llvm/llvm-project/pull/143035