[llvm] [Scalar] Use std::move (NFC) (PR #136264)

[Nikita Popov via llvm-commits]

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@@ -3327,7 +3327,7 @@ static void computeLiveInValues(DominatorTree &DT, Function &F,
     Data.LiveOut[BB] = LiveOut;
 
     // Apply the effects of this basic block
-    SetVector<Value *> LiveTmp = LiveOut;
+    SetVector<Value *> LiveTmp = std::move(LiveOut);
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nikic wrote:

If I'm reading the code above right, we're first copying `Data.LiveOut[BB]` into `LiveOut`, then we're updating `LiveOut`, and then we copy back into `Data.LiveOut[BB]`. Wouldn't it make more sense to make `LiveOut` a reference? In that case this one here would stay a copy.

https://github.com/llvm/llvm-project/pull/136264