[llvm] [LV] Prefer DenseMap::lookup over find (NFC) (PR #141809)

[Florian Hahn via llvm-commits]

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@@ -10160,7 +10160,7 @@ preparePlanForEpilogueVectorLoop(VPlan &Plan, Loop *L,
     if (!ExpandR)
       continue;
     auto *ExpandedVal =
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fhahn wrote:

```suggestion
    VPValue *ExpandedVal =
```

now we can spell out the simple type

https://github.com/llvm/llvm-project/pull/141809