[llvm] [Xtensa] Implement THREADPTR and DFPAccel Xtensa Options. (PR #145543)

[Matt Arsenault via llvm-commits]

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@@ -919,6 +920,52 @@ SDValue XtensaTargetLowering::LowerGlobalAddress(SDValue Op,
   return Res;
 }
 
+SDValue XtensaTargetLowering::LowerGlobalTLSAddress(SDValue Op,
+                                                    SelectionDAG &DAG) const {
+  const GlobalAddressSDNode *G = cast<GlobalAddressSDNode>(Op);
+  SDLoc DL(Op);
+  auto PtrVT = Op.getValueType();
+  const GlobalValue *GV = G->getGlobal();
+
+  if (DAG.getTarget().useEmulatedTLS())
+    return LowerToTLSEmulatedModel(G, DAG);
+
+  TLSModel::Model model = getTargetMachine().getTLSModel(GV);
+
+  if (!Subtarget.hasTHREADPTR()) {
+    report_fatal_error("only emulated TLS supported");
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arsenm wrote:

Avoid using report_fatal_error, in this case you can use DiagnosticInfoUnsupported and return poison 

https://github.com/llvm/llvm-project/pull/145543