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

[Nikita Popov via llvm-commits]

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@@ -1741,6 +1741,20 @@ Currently, only the following parameter attributes are defined:
 
     This attribute cannot be applied to return values.
 
+``dead_on_return``
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nikic wrote:

The wording here should be a lot more similar to dead_on_unwind, describing what the precise operational semantics of the attribute are.

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