Fix dangling IPOAmendableCB function_ref.

A temporary lambda is assigned to a llvm::function_ref, this lambda is
destroyed at the end of the full expression, any use of the function_ref
afterwards is undefined behavior.

Author: hokein

llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp

@@ -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;
 
   Attributor A(Functions, InfoCache, AC);
 

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

@@ -5809,9 +5809,10 @@ PreservedAnalyses OpenMPOptPass::run(Module &M, ModuleAnalysisManager &AM) {
   AC.OREGetter = OREGetter;
   AC.PassName = DEBUG_TYPE;
   AC.InitializationCallback = OpenMPOpt::registerAAsForFunction;
-  AC.IPOAmendableCB = [](const Function &F) {
+  auto IPOAmendableCB = [](const Function &F) {
     return F.hasFnAttribute("kernel");
   };
+  AC.IPOAmendableCB = IPOAmendableCB;
 
   Attributor A(Functions, InfoCache, AC);