[llvm] [AArch64] Convert concat(uhadd(a,b), uhadd(c,d)) to uhadd(concat(a,c), concat(b,d)) (PR #79464)

[David Green via llvm-commits]

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@@ -18240,29 +18233,10 @@ static SDValue performConcatVectorsCombine(SDNode *N,
     EVT N00VT = N00.getValueType();
     EVT N10VT = N10.getValueType();
 
-    if (N00->getOpcode() == ISD::EXTRACT_SUBVECTOR &&
-        N01->getOpcode() == ISD::EXTRACT_SUBVECTOR &&
-        N10->getOpcode() == ISD::EXTRACT_SUBVECTOR &&
-        N11->getOpcode() == ISD::EXTRACT_SUBVECTOR && N00VT == N10VT) {
-      SDValue N00Source = N00->getOperand(0);
-      SDValue N01Source = N01->getOperand(0);
-      SDValue N10Source = N10->getOperand(0);
-      SDValue N11Source = N11->getOperand(0);
-
-      if (N00Source == N10Source && N01Source == N11Source &&
-          N00Source.getValueType() == VT && N01Source.getValueType() == VT) {
-        assert(N0.getValueType() == N1.getValueType());
-
-        uint64_t N00Index = N00.getConstantOperandVal(1);
-        uint64_t N01Index = N01.getConstantOperandVal(1);
-        uint64_t N10Index = N10.getConstantOperandVal(1);
-        uint64_t N11Index = N11.getConstantOperandVal(1);
-
-        if (N00Index == N01Index && N10Index == N11Index && N00Index == 0 &&
-            N10Index == N00VT.getVectorNumElements())
-          return DAG.getNode(N0Opc, dl, VT, N00Source, N01Source);
-      }
-    }
+    EVT PairVT = N00VT.getDoubleNumVectorElementsVT(*DAG.getContext());
+    SDValue Concat0 = DAG.getNode(ISD::CONCAT_VECTORS, dl, VT, N00, N10);
+    SDValue Concat1 = DAG.getNode(ISD::CONCAT_VECTORS, dl, VT, N01, N11);
+    return DAG.getNode(N0Opc, dl, PairVT, Concat0, Concat1);
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davemgreen wrote:

PairVT -> VT

https://github.com/llvm/llvm-project/pull/79464