Unbreak the test suite after 8e8176c

The atexit logic needs to handle functions bitcast to the right type
rather than assume that the passed in constant is literally
llvm::FunctionType.

clang/lib/CodeGen/CGDeclCXX.cpp

@@ -276,8 +276,10 @@ void CodeGenFunction::registerGlobalDtorWithAtExit(const VarDecl &VD,
 
 void CodeGenFunction::registerGlobalDtorWithAtExit(llvm::Constant *dtorStub) {
   // extern "C" int atexit(void (*f)(void));
-  assert(cast<llvm::Function>(dtorStub)->getFunctionType() ==
-             llvm::FunctionType::get(CGM.VoidTy, false) &&
+  llvm::PointerType *Expected =
+      llvm::PointerType::get(llvm::FunctionType::get(CGM.VoidTy, false),
+                             dtorStub->getType()->getPointerAddressSpace());
+  assert(dtorStub->getType() == Expected &&
          "Argument to atexit has a wrong type.");
 
   llvm::FunctionType *atexitTy =