[llvm] [memprof] Migrate away from PointerUnion::dyn_cast (NFC) (PR #123716)

[Nikita Popov via llvm-commits]

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@@ -3579,7 +3579,7 @@ void ModuleCallsiteContextGraph::updateCall(CallInfo &CallerCall,
 
 void IndexCallsiteContextGraph::updateCall(CallInfo &CallerCall,
                                            FuncInfo CalleeFunc) {
-  auto *CI = CallerCall.call().dyn_cast<CallsiteInfo *>();
+  auto *CI = dyn_cast<CallsiteInfo *>(CallerCall.call());
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nikic wrote:

```suggestion
  auto *CI = cast<CallsiteInfo *>(CallerCall.call());
```

https://github.com/llvm/llvm-project/pull/123716