[cornstalks]

It's similar, but the whole point of the trick here is to move the generated code so it doesn't "pollute" the instruction cache in the CPU. __builtin_expect still puts the error-handling instructions right next to the rest of the code. The lambda puts the error-handling instructions elsewhere.

Whether or not this will impact performance depends, and will need some careful profiling. But I can imagine some situations where keeping the "hot" instructions in the cache and the "cold" (error-handling) instructions out of the cache could be beneficial.

[rlpb]

> __builtin_expect still puts the error-handling instructions right next to the rest of the code. The lambda puts the error-handling instructions elsewhere.

Surely that's a decision for the optimizer to make, in the case of __builtin_expect?