GpuLaneIndex¶

The lane of the running thread within its iteration.

Declaration¶

Syntax¶

GpuLaneIndex(ttype type, expr? value)

Arguments¶

Argument	Description
`type`	the type of the expression, an integer.
`value`	always `nil`: the lane is only known when the kernel runs.

Return values¶

The value of the expression.

Description¶

In a kernel whose layout has lanes (see gpu_kernel_layout), each iteration runs on lanes consecutive threads of one SIMD-group. The thread index (GpuThreadIndex) numbers the iterations, and GpuLaneIndex tells apart the lanes of one: it counts from zero to lanes - 1. A loop whose iterations the lanes share starts at its first iteration plus the lane and steps by lanes iterations. Only such a kernel has one.

Examples¶

(GpuLaneIndex
  :type (Integer
    :kind 4
  )
  :value nil
)