bailoutExpected feels like a hack and it's causing a JM "compile, destroy, compile, compile" cycle in bug 785755. Almost all time there is spend JM-compiling the same script. bailoutExpected was added to avoid cases where we bailout all the time because no state is updated after a bailout, and the generated code does not handle all cases. For instance "x >>> y" with known-double result (bug 785974). It would be really nice if we could just remove it and replace it with something simpler - maybe mark the script as uncompilable after some bailouts. We should also check which bailouts are really necessary or can be easily handled in JIT-code.