[clang] [llvm] [IR] Make dead_on_return attribute optionally sized (PR #171712)

[Nikita Popov via cfe-commits]

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@@ -78,8 +78,10 @@ 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.
-  LLVM_ABI bool hasDeadOnReturnAttr() const;
+  /// Return the number of bytes marked dead by the dead_on_return attribute.
+  /// If no count was specified (implying all memory reachable through the
+  /// pointer is marked dead on return), std::nullopt is returned.
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nikic wrote:

Not an std::optional so no std::nullopt?

https://github.com/llvm/llvm-project/pull/171712