[llvm] [X86][NFC] Use std::move to avoid copy (PR #141455)

[Craig Topper via llvm-commits]

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@@ -41193,7 +41193,7 @@ static SDValue combineX86ShufflesRecursively(
     resolveTargetShuffleFromZeroables(OpMask, OpUndef, OpZero,
                                       ResolveKnownZeros);
 
-    Mask = OpMask;
+    Mask = std::move(OpMask);
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topperc wrote:

Since OpMask and Mask are SmallVectors, this doesn't avoid a copy if the small storage is being used. The data has to be copied from the small storage of OpMask. I believe the SmallVectors are sized so that they are always using the small size.

https://github.com/llvm/llvm-project/pull/141455