[llvm] [SLP][NFC] Minor code simplifications (PR #149029)

[Alexey Bataev via llvm-commits]

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@@ -22207,10 +22205,9 @@ class HorizontalReduction {
     for (auto &PossibleReducedVals : PossibleReducedValsVect) {
       auto PossibleRedVals = PossibleReducedVals.second.takeVector();
       SmallVector<SmallVector<Value *>> PossibleRedValsVect;
-      for (auto It = PossibleRedVals.begin(), E = PossibleRedVals.end();
-           It != E; ++It) {
+      for (auto &It : PossibleRedVals) {
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alexey-bataev wrote:

`It`->`Slice`? Or something else

https://github.com/llvm/llvm-project/pull/149029