[llvm] Fix dangling IPOAmendableCB function_ref. (PR #120698)

[Gábor Horváth via llvm-commits]

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@@ -1352,9 +1352,10 @@ static bool runImpl(Module &M, AnalysisGetter &AG, TargetMachine &TM,
         return !AMDGPU::isEntryFunctionCC(Callee.getCallingConv()) &&
                (NumAssumedCallees <= IndirectCallSpecializationThreshold);
       };
-  AC.IPOAmendableCB = [](const Function &F) {
+  auto IPOAmendableCB = [](const Function &F) {
     return F.getCallingConv() == CallingConv::AMDGPU_KERNEL;
   };
+  AC.IPOAmendableCB = IPOAmendableCB;
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Xazax-hun wrote:

The fix looks good to me, but I wonder if the code authors might want to change these APIs as it looks really error prone to use. 

https://github.com/llvm/llvm-project/pull/120698