radv: Link shaders.

Here we make use of NIR the linking helpers to remove unused
varyings.

Sascha Willems demo results:

computecullandlod 39 -> 41 fps
pipelines ~6100 -> ~6200 fps

Signed-off-by: Bas Nieuwenhuizen <[email protected]>
Signed-off-by: Timothy Arceri <[email protected]>
Acked-by: Dave Airlie <[email protected]>

3 files changed, 46 insertions, 1 deletions

diff --git a/src/amd/vulkan/radv_pipeline.c b/src/amd/vulkan/radv_pipeline.c
index e95925fda58..559862678e7 100644
--- a/src/amd/vulkan/radv_pipeline.c
+++ b/src/amd/vulkan/radv_pipeline.c
@@ -1522,6 +1522,46 @@ static void calculate_ps_inputs(struct radv_pipeline *pipeline)
 	pipeline->graphics.ps_input_cntl_num = ps_offset;
 }
 
+static void
+radv_link_shaders(struct radv_pipeline *pipeline, nir_shader **shaders)
+{
+	nir_shader* ordered_shaders[MESA_SHADER_STAGES];
+	int shader_count = 0;
+
+	if(shaders[MESA_SHADER_FRAGMENT]) {
+		ordered_shaders[shader_count++] = shaders[MESA_SHADER_FRAGMENT];
+	}
+	if(shaders[MESA_SHADER_GEOMETRY]) {
+		ordered_shaders[shader_count++] = shaders[MESA_SHADER_GEOMETRY];
+	}
+	if(shaders[MESA_SHADER_TESS_EVAL]) {
+		ordered_shaders[shader_count++] = shaders[MESA_SHADER_TESS_EVAL];
+	}
+	if(shaders[MESA_SHADER_TESS_CTRL]) {
+		ordered_shaders[shader_count++] = shaders[MESA_SHADER_TESS_CTRL];
+	}
+	if(shaders[MESA_SHADER_VERTEX]) {
+		ordered_shaders[shader_count++] = shaders[MESA_SHADER_VERTEX];
+	}
+
+	for (int i = 1; i < shader_count; ++i)  {
+		nir_remove_dead_variables(ordered_shaders[i],
+					  nir_var_shader_out);
+		nir_remove_dead_variables(ordered_shaders[i - 1],
+					  nir_var_shader_in);
+
+		bool progress = nir_remove_unused_varyings(ordered_shaders[i],
+							   ordered_shaders[i - 1]);
+
+		if (progress) {
+			nir_lower_global_vars_to_local(ordered_shaders[i]);
+			radv_optimize_nir(ordered_shaders[i]);
+			nir_lower_global_vars_to_local(ordered_shaders[i - 1]);
+			radv_optimize_nir(ordered_shaders[i - 1]);
+		}
+	}
+}
+
 static
 void radv_create_shaders(struct radv_pipeline *pipeline,
                          struct radv_device *device,
@@ -1588,6 +1628,8 @@ void radv_create_shaders(struct radv_pipeline *pipeline,
 		nir_lower_tes_patch_vertices(nir[MESA_SHADER_TESS_EVAL], nir[MESA_SHADER_TESS_CTRL]->info.tess.tcs_vertices_out);
 	}
 
+	radv_link_shaders(pipeline, nir);
+
 	if (nir[MESA_SHADER_FRAGMENT]) {
 		pipeline->shaders[MESA_SHADER_FRAGMENT] =
 			radv_shader_variant_create(device, modules[MESA_SHADER_FRAGMENT], nir[MESA_SHADER_FRAGMENT],
diff --git a/src/amd/vulkan/radv_shader.c b/src/amd/vulkan/radv_shader.c
index d4bef9792ec..055787a7059 100644
--- a/src/amd/vulkan/radv_shader.c
+++ b/src/amd/vulkan/radv_shader.c
@@ -110,7 +110,7 @@ void radv_DestroyShaderModule(
 	vk_free2(&device->alloc, pAllocator, module);
 }
 
-static void
+void
 radv_optimize_nir(struct nir_shader *shader)
 {
         bool progress;
diff --git a/src/amd/vulkan/radv_shader.h b/src/amd/vulkan/radv_shader.h
index 1ef13968f97..3862b3094cb 100644
--- a/src/amd/vulkan/radv_shader.h
+++ b/src/amd/vulkan/radv_shader.h
@@ -67,6 +67,9 @@ struct radv_shader_slab {
 	char *ptr;
 };
 
+void
+radv_optimize_nir(struct nir_shader *shader);
+
 nir_shader *
 radv_shader_compile_to_nir(struct radv_device *device,
 			   struct radv_shader_module *module,