GpuDiscard¶

Forgets what pending kernel launches write into variables the host frees.

Declaration¶

Syntax¶

GpuDiscard(expr* vars)

Arguments¶

Argument	Description
`vars`	the variables, arrays or derived-type values.

Return values¶

None.

Description¶

A GpuKernelLaunch does not wait for its kernel, and the device keeps what the kernel writes until a GpuSync copies it back. GpuDiscard comes before the host frees the storage of vars -- at the end of the block they are locals of, or before they are deallocated -- while a launch that writes them may be pending: the values are not needed, so instead of waiting for them the runtime forgets them, and copies nothing back into storage that no longer exists.

The gpu_launch_sync pass places it; see GPU offloading.

Examples¶

(GpuDiscard
  :vars [
    (Var
      :v (SymbolRef 2 "a")
    )
  ]
)