[llvm] [AArch664] Replace uaddlv with addv for popcount operation (PR #121934)

[Usha Gupta via llvm-commits]

================
@@ -10700,37 +10700,50 @@ SDValue AArch64TargetLowering::LowerCTPOP_PARITY(SDValue Op,
   //  FMOV    D0, X0        // copy 64-bit int to vector, high bits zero'd
   //  CNT     V0.8B, V0.8B  // 8xbyte pop-counts
   //  ADDV    B0, V0.8B     // sum 8xbyte pop-counts
-  //  UMOV    X0, V0.B[0]   // copy byte result back to integer reg
+  //  FMOV    X0, D0        // copy result back to integer reg
   if (VT == MVT::i32 || VT == MVT::i64) {
     if (VT == MVT::i32)
       Val = DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i64, Val);
     Val = DAG.getNode(ISD::BITCAST, DL, MVT::v8i8, Val);
 
     SDValue CtPop = DAG.getNode(ISD::CTPOP, DL, MVT::v8i8, Val);
-    SDValue UaddLV = DAG.getNode(AArch64ISD::UADDLV, DL, MVT::v4i32, CtPop);
-    UaddLV = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, MVT::i32, UaddLV,
+    SDValue AddV;
+    if (IsParity) {
----------------
usha1830 wrote:

Yeah. It looks like it could use the same instruction. I will update it use addv and see if it causes any issues.

https://github.com/llvm/llvm-project/pull/121934