[llvm] [Hexagon] Correctly split masked loads/stores after widening (PR #190689)

[Yashas Andaluri via llvm-commits]

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@@ -3443,41 +3443,60 @@ HexagonTargetLowering::SplitVectorOp(SDValue Op, SelectionDAG &DAG) const {
 SDValue
 HexagonTargetLowering::SplitHvxMemOp(SDValue Op, SelectionDAG &DAG) const {
   auto *MemN = cast<MemSDNode>(Op.getNode());
+  unsigned MemOpc = MemN->getOpcode();
+  EVT MemTy = MemN->getMemoryVT();
 
-  if (!MemN->getMemoryVT().isSimple())
+  if ((MemOpc == ISD::STORE || MemOpc == ISD::LOAD) &&
+      (!MemTy.isSimple() || !isHvxPairTy(MemTy.getSimpleVT())))
     return Op;
 
-  MVT MemTy = MemN->getMemoryVT().getSimpleVT();
-  if (!isHvxPairTy(MemTy))
-    return Op;
+  EVT ValueType;
+  if (MemOpc == ISD::STORE)
+    ValueType = ty(cast<StoreSDNode>(Op)->getValue());
+  else if (MemOpc == ISD::MSTORE)
+    ValueType = ty(cast<MaskedStoreSDNode>(Op)->getValue());
+  else // ISD::LOAD, ISD::MLOAD.
+    ValueType = MemN->getValueType(0);
+
+  EVT LoVT, HiVT;
+  std::tie(LoVT, HiVT) = DAG.GetSplitDestVTs(ValueType);
+
+  EVT LoMemVT, HiMemVT;
+  bool HiIsEmpty = false;
+  std::tie(LoMemVT, HiMemVT) =
+      DAG.GetDependentSplitDestVTs(MemTy, LoVT, &HiIsEmpty);
+
+  uint64_t LoSize = LoMemVT.getSizeInBits().getFixedValue() / 8;
+  uint64_t HiSize = HiMemVT.getSizeInBits().getFixedValue() / 8;
 
   const SDLoc &dl(Op);
-  unsigned HwLen = Subtarget.getVectorLength();
-  MVT SingleTy = typeSplit(MemTy).first;
   SDValue Chain = MemN->getChain();
   SDValue Base0 = MemN->getBasePtr();
   SDValue Base1 =
-      DAG.getMemBasePlusOffset(Base0, TypeSize::getFixed(HwLen), dl);
-  unsigned MemOpc = MemN->getOpcode();
+      DAG.getMemBasePlusOffset(Base0, TypeSize::getFixed(LoSize), dl);
 
   MachineMemOperand *MOp0 = nullptr, *MOp1 = nullptr;
   if (MachineMemOperand *MMO = MemN->getMemOperand()) {
     MachineFunction &MF = DAG.getMachineFunction();
-    uint64_t MemSize = (MemOpc == ISD::MLOAD || MemOpc == ISD::MSTORE)
-                           ? (uint64_t)MemoryLocation::UnknownSize
-                           : HwLen;
-    MOp0 = MF.getMachineMemOperand(MMO, 0, MemSize);
-    MOp1 = MF.getMachineMemOperand(MMO, HwLen, MemSize);
+    auto MemSize = [=](uint64_t Size) {
+      return (MemOpc == ISD::MLOAD || MemOpc == ISD::MSTORE)
+                 ? (uint64_t)MemoryLocation::UnknownSize
+                 : Size;
+    };
+    MOp0 = MF.getMachineMemOperand(MMO, 0, MemSize(LoSize));
+    MOp1 = MF.getMachineMemOperand(MMO, LoSize, MemSize(HiSize));
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yandalur wrote:

HiIsEmpty cannot be true, when isHvxPairTy holds for ISD::LOAD and ISD::STORE? We can have an assert for !HiIsEmpty

https://github.com/llvm/llvm-project/pull/190689