Skip to main content

## writelane_u32

# Function writelane_u32

Source

    pub unsafe fn writelane_u32(value: u32, lane: u32, default: u32) -> u32

🔬This is a nightly-only experimental API. (`stdarch_amdgpu` #149988)
Available on AMD GPU only.
Expand description

Return `value` for the lane at index `lane` in the wavefront. Return `default` for all other lanes.

The value to write and lane select arguments must be uniform across the currently active threads of the current wavefront. Otherwise, the result is undefined.

`value` is the value returned by `lane`. `default` is the value returned by all lanes other than `lane`.

This intrinsic does not behave like a normal function call; it is a “convergent” operation and as such has non-standard control-flow effects which need special treatment by the language. Rust currently does not properly support convergent operations. This operation is hence provided on a best-effort basis. Using it may result in incorrect code under some circumstances.