radv: rework how the number of VGPRs is computed

Just a cleanup, it shouldn't change anything.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

src/amd/vulkan/radv_nir_to_llvm.c

@@ -2191,14 +2191,6 @@ handle_vs_input_decl(struct radv_shader_context *ctx,
 					buffer_index = LLVMBuildUDiv(ctx->ac.builder, buffer_index,
 					                             LLVMConstInt(ctx->ac.i32, divisor, 0), "");
 				}
-
-				if (ctx->options->key.vs.as_ls) {
-					ctx->shader_info->vs.vgpr_comp_cnt =
-						MAX2(2, ctx->shader_info->vs.vgpr_comp_cnt);
-				} else {
-					ctx->shader_info->vs.vgpr_comp_cnt =
-						MAX2(1, ctx->shader_info->vs.vgpr_comp_cnt);
-				}
 			} else {
 				buffer_index = ctx->ac.i32_0;
 			}
@@ -3047,8 +3039,6 @@ handle_vs_outputs_post(struct radv_shader_context *ctx,
 		LLVMValueRef values[4];
 
 		values[0] = ctx->vs_prim_id;
-		ctx->shader_info->vs.vgpr_comp_cnt = MAX2(2,
-							  ctx->shader_info->vs.vgpr_comp_cnt);
 		for (unsigned j = 1; j < 4; j++)
 			values[j] = ctx->ac.f32_0;
 
@@ -3756,15 +3746,6 @@ LLVMModuleRef ac_translate_nir_to_llvm(struct ac_llvm_compiler *ac_llvm,
 			ctx.tcs_vertices_per_patch = shaders[i]->info.tess.tcs_vertices_out;
 			ctx.tcs_num_patches = ctx.options->key.tes.num_patches;
 		} else if (shaders[i]->info.stage == MESA_SHADER_VERTEX) {
-			if (shader_info->info.vs.needs_instance_id) {
-				if (ctx.options->key.vs.as_ls) {
-					ctx.shader_info->vs.vgpr_comp_cnt =
-						MAX2(2, ctx.shader_info->vs.vgpr_comp_cnt);
-				} else {
-					ctx.shader_info->vs.vgpr_comp_cnt =
-						MAX2(1, ctx.shader_info->vs.vgpr_comp_cnt);
-				}
-			}
 			ctx.abi.load_base_vertex = radv_load_base_vertex;
 		} else if (shaders[i]->info.stage == MESA_SHADER_FRAGMENT) {
 			shader_info->fs.can_discard = shaders[i]->info.fs.uses_discard;
@@ -3999,9 +3980,6 @@ ac_fill_shader_info(struct radv_shader_variant_info *shader_info, struct nir_sha
         case MESA_SHADER_VERTEX:
                 shader_info->vs.as_es = options->key.vs.as_es;
                 shader_info->vs.as_ls = options->key.vs.as_ls;
-                /* in LS mode we need at least 1, invocation id needs 2, handled elsewhere */
-                if (options->key.vs.as_ls)
-                        shader_info->vs.vgpr_comp_cnt = MAX2(1, shader_info->vs.vgpr_comp_cnt);
                 break;
         default:
                 break;

src/amd/vulkan/radv_shader.c

@@ -507,13 +507,40 @@ radv_fill_shader_variant(struct radv_device *device,
 		break;
 	case MESA_SHADER_TESS_CTRL:
 		if (device->physical_device->rad_info.chip_class >= GFX9) {
-			vgpr_comp_cnt = variant->info.vs.vgpr_comp_cnt;
+			/* We need at least 2 components for LS.
+			 * VGPR0-3: (VertexID, RelAutoindex, InstanceID / StepRate0, InstanceID).
+			 * StepRate0 is set to 1. so that VGPR3 doesn't have to be loaded.
+			 */
+			vgpr_comp_cnt = info->vs.needs_instance_id ? 2 : 1;
 		} else {
 			variant->rsrc2 |= S_00B12C_OC_LDS_EN(1);
 		}
 		break;
 	case MESA_SHADER_VERTEX:
-		vgpr_comp_cnt = variant->info.vs.vgpr_comp_cnt;
+		if (variant->info.vs.as_ls) {
+			assert(device->physical_device->rad_info.chip_class <= GFX8);
+			/* We need at least 2 components for LS.
+			 * VGPR0-3: (VertexID, RelAutoindex, InstanceID / StepRate0, InstanceID).
+			 * StepRate0 is set to 1. so that VGPR3 doesn't have to be loaded.
+			 */
+			vgpr_comp_cnt = info->vs.needs_instance_id ? 2 : 1;
+		} else if (variant->info.vs.as_es) {
+			assert(device->physical_device->rad_info.chip_class <= GFX8);
+			/* VGPR0-3: (VertexID, InstanceID / StepRate0, ...) */
+			vgpr_comp_cnt = info->vs.needs_instance_id ? 1 : 0;
+		} else {
+			/* VGPR0-3: (VertexID, InstanceID / StepRate0, PrimID, InstanceID)
+			 * If PrimID is disabled. InstanceID / StepRate1 is loaded instead.
+			 * StepRate0 is set to 1. so that VGPR3 doesn't have to be loaded.
+			 */
+			if (options->key.vs.export_prim_id) {
+				vgpr_comp_cnt = 2;
+			} else if (info->vs.needs_instance_id) {
+				vgpr_comp_cnt = 1;
+			} else {
+				vgpr_comp_cnt = 0;
+			}
+		}
 		break;
 	case MESA_SHADER_FRAGMENT:
 	case MESA_SHADER_GEOMETRY:
@@ -539,7 +566,8 @@ radv_fill_shader_variant(struct radv_device *device,
 		unsigned gs_vgpr_comp_cnt, es_vgpr_comp_cnt;
 
 		if (es_type == MESA_SHADER_VERTEX) {
-			es_vgpr_comp_cnt = variant->info.vs.vgpr_comp_cnt;
+			/* VGPR0-3: (VertexID, InstanceID / StepRate0, ...) */
+			es_vgpr_comp_cnt = info->vs.needs_instance_id ? 1 : 0;
 		} else if (es_type == MESA_SHADER_TESS_EVAL) {
 			es_vgpr_comp_cnt = info->uses_prim_id ? 3 : 2;
 		} else {

src/amd/vulkan/radv_shader.h

@@ -266,7 +266,6 @@ struct radv_shader_variant_info {
 		struct {
 			struct radv_vs_output_info outinfo;
 			struct radv_es_output_info es_info;
-			unsigned vgpr_comp_cnt;
 			bool as_es;
 			bool as_ls;
 		} vs;