select_unpredictable in std::intrinsics - Rust (original) (raw)

Function select_unpredictable

Source

pub fn select_unpredictable<T>(b: bool, true_val: T, false_val: T) -> T

🔬This is a nightly-only experimental API. (core_intrinsics)

Expand description

Returns either true_val or false_val depending on condition b with a hint to the compiler that this condition is unlikely to be correctly predicted by a CPU’s branch predictor (e.g. a binary search).

This is otherwise functionally equivalent to if b { true_val } else { false_val }.

Note that, unlike most intrinsics, this is safe to call; it does not require an unsafe block. Therefore, implementations must not require the user to uphold any safety invariants.

The public form of this instrinsic is bool::select_unpredictable.