What optimizations are disabled? I don't see any reason any of them would be, nor is there any bookkeeping. The stack itself is the bookkeeping which is require

What optimizations are disabled? I don't see any reason any of them would be, nor is there any bookkeeping. The stack itself is the bookkeeping which is required regardless. The exception-specific stuff is stored elsewhere, which is why throwing an exception is expensive, but if it doesn't throw then nothing in the hot path was pessimised.