[Mesa-dev] [PATCH 4.5/7] nir: add list_head to nir_src::ssa

[Jason Ekstrand]

On Mon, Oct 26, 2015 at 8:26 AM, Rob Clark <robdclark at gmail.com> wrote:
> From: Rob Clark <robclark at freedesktop.org>
>
> This will be used by clone.  Possibly useful elsewhere.  The list link
> will only be valid in ssa case, it fits in the padding in the union
> left from the larger nir_reg_src.

We already have a use_link.  It seems perfectly reasonable to me to
overload it in the middle of a copy operation.
--Jason

> Signed-off-by: Rob Clark <robclark at freedesktop.org>
> ---
>  src/glsl/nir/nir.h | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
> index 2d9c94c..fb60340 100644
> --- a/src/glsl/nir/nir.h
> +++ b/src/glsl/nir/nir.h
> @@ -528,7 +528,12 @@ typedef struct nir_src {
>
>     union {
>        nir_reg_src reg;
> -      nir_ssa_def *ssa;
> +      struct {
> +         /* used in clone to track unresolved ssa src's: */
> +         struct list_head link;
> +
> +         nir_ssa_def *ssa;
> +      };
>     };
>
>     bool is_ssa;
> --
> 2.5.0
>