[llvm] [WPD]Regard unreachable function as a possible devirtualizable target (PR #115668)

[Teresa Johnson via llvm-commits]

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@@ -167,6 +167,18 @@ static cl::list<std::string>
                       cl::desc("Prevent function(s) from being devirtualized"),
                       cl::Hidden, cl::CommaSeparated);
 
+/// A function is unreachable if its entry block ends with 'unreachable' IR
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teresajohnson wrote:

related - probably update the description which currently says that this is about pure virtual functions, but most of those are already handled due to the __cxa_pure_virtual in the vtable slot.

https://github.com/llvm/llvm-project/pull/115668