[clang] [llvm] [Clang] Add `__builtin_stack_address` (PR #148281)

[Matt Arsenault via llvm-commits]

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@@ -3680,6 +3681,7 @@ bool SelectionDAGLegalize::ExpandNode(SDNode *Node) {
     Results.push_back(Tmp1);
     break;
   }
+  case ISD::STACKADDRESS:
   case ISD::STACKSAVE:
     // Expand to CopyFromReg if the target set
     // StackPointerRegisterToSaveRestore.
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arsenm wrote:

No, we should be using diagnostic info more for this kind of thing. Though we should have separate kinds for will-never-be-supported type cases, and missing functionality 

https://github.com/llvm/llvm-project/pull/148281