[llvm] [AArch64][SelectionDAG] Implement vector splitting for histogram intrinsic (PR #103037)

[Max Beck-Jones via llvm-commits]

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@@ -4274,6 +4277,31 @@ SDValue DAGTypeLegalizer::SplitVecOp_VP_CttzElements(SDNode *N) {
                        DAG.getNode(ISD::ADD, DL, ResVT, VLo, ResHi));
 }
 
+SDValue DAGTypeLegalizer::SplitVecOp_VECTOR_HISTOGRAM(SDNode *N) {
+  MaskedHistogramSDNode *HG = cast<MaskedHistogramSDNode>(N);
+  SDLoc DL(HG);
+  SDValue Chain = HG->getChain();
+  SDValue Inc = HG->getInc();
+  SDValue Mask = HG->getMask();
+  SDValue Ptr = HG->getBasePtr();
+  SDValue Index = HG->getIndex();
+  SDValue Scale = HG->getScale();
+  SDValue IntID = HG->getIntID();
+  EVT MemVT = HG->getMemoryVT();
+  MachineMemOperand *MMO = HG->getMemOperand();
+  ISD::MemIndexType IndexType = HG->getIndexType();
+
+  SDValue IndexLo, IndexHi, MaskLo, MaskHi;
+  std::tie(IndexLo, IndexHi) = DAG.SplitVector(Index, DL);
+  std::tie(MaskLo, MaskHi) = DAG.SplitVector(Mask, DL);
+  SDValue HistogramOpsLo[] = {Chain, Inc, MaskLo, Ptr, IndexLo, Scale, IntID};
+  SDValue HChain = DAG.getMaskedHistogram(DAG.getVTList(MVT::Other), MemVT, DL,
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DevM-uk wrote:

Done.

https://github.com/llvm/llvm-project/pull/103037