[llvm] [AArch64] Utilize `XAR` for certain vector rotates (PR #137629)

[David Green via llvm-commits]

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@@ -4558,9 +4558,27 @@ bool AArch64DAGToDAGISel::trySelectXAR(SDNode *N) {
         !TLI->isAllActivePredicate(*CurDAG, N1.getOperand(0)))
       return false;
 
-    SDValue XOR = N0.getOperand(1);
-    if (XOR.getOpcode() != ISD::XOR || XOR != N1.getOperand(1))
-      return false;
+    SDValue R1, R2;
+    if (N0.getOperand(1).getOpcode() != ISD::XOR) {
+      if (N0.getOperand(1) != N1.getOperand(1))
+        return false;
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davemgreen wrote:

Should this be in the else branch too, or shared between them?

https://github.com/llvm/llvm-project/pull/137629