Functions§

assert_unchecked^⚠

Makes asoundness promise to the compiler thatcond holds.

black_box

An identity function thathints to the compiler to be maximally pessimistic about whatblack_box could do.

select_unpredictable

Returns eithertrue_val orfalse_val depending on the value ofcondition, with a hint to the compiler thatcondition is unlikely to becorrectly predicted by a CPU’s branch predictor.

spin_loop

Emits a machine instruction to signal the processor that it is running ina busy-wait spin-loop (“spin lock”).

unreachable_unchecked^⚠

Informs the compiler that the site which is calling this function is notreachable, possibly enabling further optimizations.

cold_pathExperimental

Hints to the compiler that given path is cold, i.e., unlikely to be taken. The compiler maychoose to optimize paths that are not cold at the expense of paths that are cold.

likelyExperimental

Hints to the compiler that a branch condition is likely to be true.Returns the value passed to it.

must_useExperimental

An identity function that causes anunused_must_use warning to betriggered if the given value is not used (returned, stored in a variable,etc) by the caller.

unlikelyExperimental

Hints to the compiler that a branch condition is unlikely to be true.Returns the value passed to it.