# Function std::intrinsics::assume

const: unstable · source ·

    pub unsafe extern "rust-intrinsic" fn assume(b: bool)

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

Informs the optimizer that a condition is always true. If the condition is false, the behavior is undefined.

No code is generated for this intrinsic, but the optimizer will try to preserve it (and its condition) between passes, which may interfere with optimization of surrounding code and reduce performance. It should not be used if the invariant can be discovered by the optimizer on its own, or if it does not enable any significant optimizations.

This intrinsic does not have a stable counterpart.