[Mesa-dev] [PATCH 2/9] radv: start conditionalising vertex inputs.

[Dave Airlie]

On 18 April 2017 at 15:07, Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl> wrote:
> On Tue, Apr 18, 2017 at 5:57 AM, Dave Airlie <airlied at gmail.com> wrote:
>> From: Dave Airlie <airlied at redhat.com>
>>
>> In practice this will probably just drop draw id in a few places.
>>
>> Signed-off-by: Dave Airlie <airlied at redhat.com>
>> ---
>>  src/amd/common/ac_nir_to_llvm.c  | 42 +++++++++++++++++++++++++++-----------
>>  src/amd/common/ac_shader_info.c  | 26 ++++++++++++++++++++++++
>>  src/amd/common/ac_shader_info.h  |  5 +++++
>>  src/amd/vulkan/radv_cmd_buffer.c | 44 +++++++++++++++++++++++++++++++---------
>>  4 files changed, 95 insertions(+), 22 deletions(-)
>>
>> diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
>> index dbb3b67..7161caf 100644
>> --- a/src/amd/common/ac_nir_to_llvm.c
>> +++ b/src/amd/common/ac_nir_to_llvm.c
>> @@ -614,10 +614,15 @@ static void create_function(struct nir_to_llvm_context *ctx)
>>                 break;
>>         case MESA_SHADER_VERTEX:
>>                 if (!ctx->is_gs_copy_shader) {
>> -                       arg_types[arg_idx++] = const_array(ctx->v16i8, 16); /* vertex buffers */
>> -                       arg_types[arg_idx++] = ctx->i32; // base vertex
>> -                       arg_types[arg_idx++] = ctx->i32; // start instance
>> -                       arg_types[arg_idx++] = ctx->i32; // draw index
>> +                       if (ctx->shader_info->info.vs.has_vertex_buffers)
>> +                               arg_types[arg_idx++] = const_array(ctx->v16i8, 16); /* vertex buffers */
>> +                       if (ctx->shader_info->info.vs.needs_base_vertex_start_instance ||
>> +                           ctx->shader_info->info.vs.needs_draw_id) {
>> +                               arg_types[arg_idx++] = ctx->i32; // base vertex
>> +                               arg_types[arg_idx++] = ctx->i32; // start instance
>
> I'm not sure we can avoid having the CP write these two to some user
> SGPRs for indirect draws? If so, we cannot skip them.

Yeah I did wonder this, it's a pity but you are probably right, I'll
rework this patch
to always allocate those two.

Dave.