radv: do not emit unnecessary ES output stores

GFX9:
Totals from affected shaders:
SGPRS: 472 -> 464 (-1.69 %)
VGPRS: 576 -> 584 (1.39 %)
Code Size: 45432 -> 44324 (-2.44 %) bytes
Max Waves: 40 -> 40 (0.00 %)

VI:
SGPRS: 720 -> 720 (0.00 %)
VGPRS: 728 -> 728 (0.00 %)
Code Size: 45348 -> 43992 (-2.99 %) bytes
Max Waves: 120 -> 120 (0.00 %)

This affects Rise of Tomb Raider and the three Vulkan demos
that use a geometry shader (geometryshader, deferredshadows
and viewportarray).

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

diff --git a/src/amd/vulkan/radv_nir_to_llvm.c b/src/amd/vulkan/radv_nir_to_llvm.c
index 05ae709..82b1e36 100644 (file)
--- a/src/amd/vulkan/radv_nir_to_llvm.c
+++ b/src/amd/vulkan/radv_nir_to_llvm.c
@@ -2582,14 +2582,26 @@ handle_es_outputs_post(struct radv_shader_context *ctx,
        for (unsigned i = 0; i < AC_LLVM_MAX_OUTPUTS; ++i) {
                LLVMValueRef dw_addr = NULL;
                LLVMValueRef *out_ptr = &ctx->abi.outputs[i * 4];
+               unsigned output_usage_mask;
                int param_index;
                int length = 4;
 
                if (!(ctx->output_mask & (1ull << i)))
                        continue;
 
-               if (i == VARYING_SLOT_CLIP_DIST0)
+               if (ctx->stage == MESA_SHADER_VERTEX) {
+                       output_usage_mask =
+                               ctx->shader_info->info.vs.output_usage_mask[i];
+               } else {
+                       assert(ctx->stage == MESA_SHADER_TESS_EVAL);
+                       output_usage_mask =
+                               ctx->shader_info->info.tes.output_usage_mask[i];
+               }
+
+               if (i == VARYING_SLOT_CLIP_DIST0) {
                        length = ctx->num_output_clips + ctx->num_output_culls;
+                       output_usage_mask = (1 << length) - 1;
+               }
 
                param_index = shader_io_get_unique_index(i);
 
@@ -2598,14 +2610,22 @@ handle_es_outputs_post(struct radv_shader_context *ctx,
                                               LLVMConstInt(ctx->ac.i32, param_index * 4, false),
                                               "");
                }
+
                for (j = 0; j < length; j++) {
+                       if (!(output_usage_mask & (1 << j)))
+                               continue;
+
                        LLVMValueRef out_val = LLVMBuildLoad(ctx->ac.builder, out_ptr[j], "");
                        out_val = LLVMBuildBitCast(ctx->ac.builder, out_val, ctx->ac.i32, "");
 
                        if (ctx->ac.chip_class  >= GFX9) {
-                               ac_lds_store(&ctx->ac, dw_addr,
+                               LLVMValueRef dw_addr_offset =
+                                       LLVMBuildAdd(ctx->ac.builder, dw_addr,
+                                                    LLVMConstInt(ctx->ac.i32,
+                                                                 j, false), "");
+
+                               ac_lds_store(&ctx->ac, dw_addr_offset,
                                             LLVMBuildLoad(ctx->ac.builder, out_ptr[j], ""));
-                               dw_addr = LLVMBuildAdd(ctx->ac.builder, dw_addr, ctx->ac.i32_1, "");
                        } else {
                                ac_build_buffer_store_dword(&ctx->ac,
                                                            ctx->esgs_ring,