[llvm] [Xtensa] Implement lowering Mul/Div/Shift operations. (PR #99981)

[Matt Arsenault via llvm-commits]

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@@ -662,15 +690,33 @@ SDValue XtensaTargetLowering::getAddrPCRel(SDValue Op,
   return DAG.getNode(XtensaISD::PCREL_WRAPPER, DL, Ty, Op);
 }
 
-SDValue XtensaTargetLowering::LowerConstantPool(ConstantPoolSDNode *CP,
+SDValue XtensaTargetLowering::LowerConstantPool(SDValue Op,
                                                 SelectionDAG &DAG) const {
-  EVT PtrVT = getPointerTy(DAG.getDataLayout());
+  EVT PtrVT = Op.getValueType();
+  ConstantPoolSDNode *CP = cast<ConstantPoolSDNode>(Op);
+  auto C = const_cast<Constant*>(CP->getConstVal());
+  auto T = CP->getType();
   SDValue Result;
-  if (!CP->isMachineConstantPoolEntry()) {
-    Result = DAG.getTargetConstantPool(CP->getConstVal(), PtrVT, CP->getAlign(),
-                                       CP->getOffset());
+
+  // Do not use constant pool for aggregate or vector constant types,
+  // in such cases create global variable, for example to store tabel
+  // when we lower CTTZ operation.
+  if (T->isAggregateType()) {
+    MachineFunction &MF = DAG.getMachineFunction();
+    auto AFI = MF.getInfo<XtensaFunctionInfo>();
+    auto M = const_cast<Module *>(MF.getFunction().getParent());
+    auto GV = new GlobalVariable(
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arsenm wrote:

Should not be mutating the IR during selection 

https://github.com/llvm/llvm-project/pull/99981