[llvm] [IPO] Prevent removal of some convergent attr (PR #134863)

[Shilei Tian via llvm-commits]

Nathan =?utf-8?q?Gau=C3=ABr?= <brioche at google.com>,
Nathan =?utf-8?q?Gau=C3=ABr?= <brioche at google.com>,
Nathan =?utf-8?q?Gau=C3=ABr?= <brioche at google.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/134863 at github.com>


================
@@ -2902,6 +2902,22 @@ struct AANonConvergentImpl : public AANonConvergent {
   }
 };
 
+static bool FunctionCalledWithConvergenceToken(const Function *F) {
+  for (auto &Use : F->uses()) {
+    CallBase *CB = dyn_cast<CallBase>(Use.getUser());
+    if (!CB)
+      continue;
+
+    // We are not called, just used as an argument.
+    if (CB->getCalledFunction() != F)
+      continue;
----------------
shiltian wrote:

```suggestion
    if (!CB || CB->getCalledFunction() != F)
      continue;
```

https://github.com/llvm/llvm-project/pull/134863