[llvm] [Xtensa] Lower GlobalAddress/BlockAddress/JumpTable (PR #95256)

[Matt Arsenault via llvm-commits]

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@@ -519,6 +537,87 @@ SDValue XtensaTargetLowering::LowerImmediate(SDValue Op,
   return Op;
 }
 
+SDValue XtensaTargetLowering::LowerGlobalAddress(SDValue Op,
+                                                 SelectionDAG &DAG) const {
+  const GlobalAddressSDNode *G = cast<GlobalAddressSDNode>(Op);
+  SDLoc DL(Op);
+  auto PtrVt = getPointerTy(DAG.getDataLayout());
+  const GlobalValue *GV = G->getGlobal();
+
+  // Check Op SDNode users
+  // If there are only CALL nodes, don't expand Global Address
+  SDNode &OpNode = *Op.getNode();
+  bool Val = false;
+  for (SDNode::use_iterator UI = OpNode.use_begin(); UI != OpNode.use_end();
+       ++UI) {
+    SDNode &User = *UI.getUse().getUser();
+    unsigned OpCode = User.getOpcode();
+    if (OpCode != XtensaISD::CALL) {
+      Val = true;
+      break;
+    }
+  }
+  if (!Val) {
+    SDValue TargAddr = DAG.getTargetGlobalAddress(G->getGlobal(), DL, PtrVt, 0,
+                                                  0 /* TargetFlags */);
+    return TargAddr;
+  }
+
+  SDValue CPAddr = DAG.getTargetConstantPool(GV, PtrVt, Align(4));
+  SDValue CPWrap = getAddrPCRel(CPAddr, DAG);
+
+  return CPWrap;
+}
+
+SDValue XtensaTargetLowering::LowerBlockAddress(BlockAddressSDNode *Node,
+                                                SelectionDAG &DAG) const {
+  const BlockAddress *BA = Node->getBlockAddress();
+  EVT PtrVT = getPointerTy(DAG.getDataLayout());
+  XtensaConstantPoolValue *CPV =
+      XtensaConstantPoolConstant::Create(BA, 0, XtensaCP::CPBlockAddress);
+  SDValue CPAddr = DAG.getTargetConstantPool(CPV, PtrVT, Align(4));
+  SDValue CPWrap = getAddrPCRel(CPAddr, DAG);
+  return CPWrap;
+}
+
+SDValue XtensaTargetLowering::LowerBR_JT(SDValue Op, SelectionDAG &DAG) const {
+  SDValue Chain = Op.getOperand(0);
+  SDValue Table = Op.getOperand(1);
+  SDValue Index = Op.getOperand(2);
+  SDLoc DL(Op);
+  JumpTableSDNode *JT = cast<JumpTableSDNode>(Table);
+  MachineFunction &MF = DAG.getMachineFunction();
+  const MachineJumpTableInfo *MJTI = MF.getJumpTableInfo();
+  SDValue TargetJT = DAG.getTargetJumpTable(JT->getIndex(), MVT::i32);
+  const DataLayout &TD = DAG.getDataLayout();
+  EVT PTy = getPointerTy(TD);
+  unsigned EntrySize = MJTI->getEntrySize(TD);
+
+  Index = DAG.getNode(ISD::MUL, DL, Index.getValueType(), Index,
+                      DAG.getConstant(EntrySize, DL, Index.getValueType()));
+  SDValue Addr = DAG.getNode(ISD::ADD, DL, Index.getValueType(), Index, Table);
+  SDValue LD =
+      DAG.getLoad(PTy, DL, Chain, Addr,
+                  MachinePointerInfo::getJumpTable(DAG.getMachineFunction()));
+  return DAG.getNode(XtensaISD::BR_JT, DL, MVT::Other, LD.getValue(1), LD,
+                     TargetJT);
+}
+
+SDValue XtensaTargetLowering::LowerJumpTable(JumpTableSDNode *JT,
+                                             SelectionDAG &DAG) const {
+  SDLoc DL(JT);
+  EVT PtrVt = getPointerTy(DAG.getDataLayout());
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arsenm wrote:

Use the type of the original node 

https://github.com/llvm/llvm-project/pull/95256