[llvm] [Attributor]: Fix Potential bug when handling PHI in AAPointerInfo (PR #97321)

[Johannes Doerfert via llvm-commits]

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@@ -214,7 +214,7 @@ ChangeStatus clampStateAndIndicateChange<DerefState>(DerefState &S,
 static bool mayBeInCycle(const CycleInfo *CI, const Instruction *I,
                          bool HeaderOnly, Cycle **CPtr = nullptr) {
   if (!CI)
-    return true;
+    return false;
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jdoerfert wrote:

We can't assume we are not in a cycle if we don't know. That leads to wrong results. We can, however, try to make sure we have cycle info for the case or use something else.

https://github.com/llvm/llvm-project/pull/97321