[llvm] Fixes [AArch64] Assertion `EltCnt.isKnownEven() && "Cannot halve vector with odd number of elements."' failed. (PR #166528)

[Shakil Ahmed via llvm-commits]

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@@ -1333,6 +1333,11 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
           TargetLowering::TypeSplitVector;
       if ((SplitSrc || SplitDst) && SrcVTy->getElementCount().isVector() &&
           DstVTy->getElementCount().isVector()) {
+        auto SrcEltCnt = SrcVTy->getElementCount();
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ahmedshakill wrote:

Sure. Could you also provide a feedback on the test added? 

https://github.com/llvm/llvm-project/pull/166528