[llvm] [VPlan] Remove loop region in optimizeForVFAndUF. (PR #108378)

[via llvm-commits]

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@@ -2954,6 +2957,8 @@ void InnerLoopVectorizer::fixVectorizedLoop(VPTransformState &State,
     for (PHINode &PN : Exit->phis())
       PSE.getSE()->forgetLcssaPhiWithNewPredecessor(OrigLoop, &PN);
 
+  if (!isa<VPRegionBlock>(State.Plan->getEntry()->getSingleSuccessor()))
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ayalz wrote:

```suggestion
  if (!State.Plan->getVectorLoopRegion())
```
which should dyn_cast instead of cast.


https://github.com/llvm/llvm-project/pull/108378