[llvm] [ARM] Lower vector interleave operations (PR #225670)

[David Green via llvm-commits]

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@@ -9067,6 +9069,103 @@ static SDValue LowerCONCAT_VECTORS_i1(SDValue Op, SelectionDAG &DAG,
   return ConcatOps[0];
 }
 
+static SDValue LowerVECTOR_INTERLEAVE(SDValue Op, SelectionDAG &DAG,
+                                      const ARMSubtarget *ST) {
+  if (!ST->hasNEON())
+    return SDValue();
+  unsigned Factor = Op->getNumOperands();
+  EVT OpVT = Op.getValueType();
+  SDLoc DL(Op);
+
+  if (Factor == 2) {
+    SDValue Zip = DAG.getNode(ARMISD::VZIP, DL, DAG.getVTList(OpVT, OpVT),
+                              Op.getOperand(0), Op.getOperand(1));
+    return DAG.getMergeValues({Zip, Zip.getValue(1)}, DL);
+  }
+
+  if (Op->getNumOperands() == 3) {
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davemgreen wrote:

Factor == 3

https://github.com/llvm/llvm-project/pull/225670