[llvm] [IR] Add `dead_on_return` attribute (PR #143271)

[Yingwei Zheng via llvm-commits]

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@@ -78,6 +78,9 @@ class Argument final : public Value {
   /// Return true if this argument has the byval attribute.
   LLVM_ABI bool hasByValAttr() const;
 
+  /// Return true if this argument has the dead_on_return attribute.
+  bool hasDeadOnReturnAttr() const;
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dtcxzyw wrote:

```suggestion
  LLVM_ABI bool hasDeadOnReturnAttr() const;
```

https://github.com/llvm/llvm-project/pull/143271