It can also change the instruction selection. For example, __builtin_unpredictable which is a close cousin of expect will indicate there's no prediction possibl

It can also change the instruction selection. For example, __builtin_unpredictable which is a close cousin of expect will indicate there's no prediction possible on a branch. This causes the compiler to select branchless instructions & is particularly useful in things like binary search where the CPU attempting to do prediction is worse than using a branchless version of the code.