[Mesa-dev] [PATCH 1/2] glsl/cs: Exclude gl_LocalInvocationIndex from builtin variable stripping

[Tapani Pälli]

These 2 patches are

Reviewed-by: Tapani Pälli <tapani.palli at intel.com>

On 08/23/2015 11:50 AM, Jordan Justen wrote:
> We lower gl_LocalInvocationIndex based on the extension spec formula:
>
>      gl_LocalInvocationIndex =
>          gl_LocalInvocationID.z * gl_WorkGroupSize.x * gl_WorkGroupSize.y +
>          gl_LocalInvocationID.y * gl_WorkGroupSize.x +
>          gl_LocalInvocationID.x;
>
> https://www.opengl.org/registry/specs/ARB/compute_shader.txt
>
> We need to set this variable in main(), even if gl_LocalInvocationIndex
> is not referenced by the shader. (It may be used by a linked shader.)
> Therefore, we can't eliminate it as a dead variable.
>
> Signed-off-by: Jordan Justen <jordan.l.justen at intel.com>
> ---
>   git://people.freedesktop.org/~jljusten/mesa cs-local-index-v1
>   http://patchwork.freedesktop.org/bundle/jljusten/cs-local-index-v1
>
>   src/glsl/opt_dead_builtin_variables.cpp | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/src/glsl/opt_dead_builtin_variables.cpp b/src/glsl/opt_dead_builtin_variables.cpp
> index 90b753e..03e5789 100644
> --- a/src/glsl/opt_dead_builtin_variables.cpp
> +++ b/src/glsl/opt_dead_builtin_variables.cpp
> @@ -72,6 +72,13 @@ optimize_dead_builtin_variables(exec_list *instructions,
>          *    gl_GlobalInvocationID =
>          *       gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID
>          *
> +       * Similarly, we initialize gl_LocalInvocationIndex in the main function:
> +       *
> +       *    gl_LocalInvocationIndex =
> +       *       gl_LocalInvocationID.z * gl_WorkGroupSize.x * gl_WorkGroupSize.y +
> +       *       gl_LocalInvocationID.y * gl_WorkGroupSize.x +
> +       *       gl_LocalInvocationID.x;
> +       *
>          * Matrix uniforms with "Transpose" are not eliminated because there's
>          * an optimization pass that can turn references to the regular matrix
>          * into references to the transpose matrix.  Eliminating the transpose
> @@ -87,6 +94,7 @@ optimize_dead_builtin_variables(exec_list *instructions,
>             || strcmp(var->name, "gl_WorkGroupSize") == 0
>             || strcmp(var->name, "gl_LocalInvocationID") == 0
>             || strcmp(var->name, "gl_GlobalInvocationID") == 0
> +          || strcmp(var->name, "gl_LocalInvocationIndex") == 0
>             || strstr(var->name, "Transpose") != NULL)
>            continue;
>