+/// \brief Test if the given class represents instructions which are never safe
+/// to mark with the "tail" keyword.
+static bool IsNeverTail(InstructionClass Class) {
+ /// It is never safe to tail call objc_autorelease since by tail calling
+ /// objc_autorelease, we also tail call -[NSObject autorelease] which supports
+ /// fast autoreleasing causing our object to be potentially reclaimed from the
+ /// autorelease pool which violates the semantics of __autoreleasing types in
+ /// ARC.
+ return Class == IC_Autorelease;
+}
+