[llvm] [LV][NFC] Improve readability with `bool` instead of `auto` (PR #111532)

[Florian Hahn via llvm-commits]

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@@ -3221,7 +3221,7 @@ void LoopVectorizationCostModel::collectLoopScalars(ElementCount VF) {
 
     // Determine if all users of the induction variable update instruction are
     // scalar after vectorization.
-    auto ScalarIndUpdate =
+    bool ScalarIndUpdate =
         llvm::all_of(IndUpdate->users(), [&](User *U) -> bool {
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fhahn wrote:

while you are editing around here, might as well drop redundant llvm::


```suggestion
        all_of(IndUpdate->users(), [&](User *U) -> bool {
```

https://github.com/llvm/llvm-project/pull/111532