[llvm] [Coroutines][LazyCallGraph] resumes are not really SCC (PR #116285)

[Arthur Eubanks via llvm-commits]

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@@ -1720,6 +1720,7 @@ void LazyCallGraph::addSplitRefRecursiveFunctions(
   for (Function *NewFunction : NewFunctions) {
     Node &NewN = initNode(*NewFunction);
 
+    // Make the original function reference each new function
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aeubanks wrote:

As long as the new functions are a RefSCC when we call `addSplitRefRecursiveFunctions()`, it's fine if they stop being a RefSCC as long as we call `updateCGAndAnalysisManagerForCGSCCPass()` after making those changes (e.g. simplify-cfg). `updateCGAndAnalysisManagerForCGSCCPass()` should handle all possible call graph changes that are legal in an SCC pass (including updating the LazyCallGraph to reflect that), and if it doesn't that's a bug in `updateCGAndAnalysisManagerForCGSCCPass()`

https://github.com/llvm/llvm-project/pull/116285