Here is an example with the very common programming patterns that result in indirect jumps/calls:

https://godbolt.org/g/LPycpY

Every single call rax and jump rax that you see on the right will be replaced with the following:

    push rax
    jmp .indirect_thunk

And indirect_thunk does an lfence and a call to another function that gets rax from the stack and jumps there in a very roundabout way that interacts terribly with CPU prediction. I can see why they somehow didn't get around to benchmarking this yet, because they are not going to like the results. And it doesn't end with the kernel. Every JIT is going to need the treatment.