radeonsi: skip TESSINNER/OUTER offchip stores if TES doesn't read them

We were unconditionally storing these outputs, sometimes even one component
at a time, but apps never read them in TES.

Move the TESSINNER/OUTER buffer stores into the TCS epilog where we can
easily disable them on demand.

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index b85874ae4031801d6a1894fea09e2ca68e6edc70..8fe25294db39a7a4d0060c9c8b490d363077b01a 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -715,6 +715,7 @@ static LLVMValueRef get_dw_address(struct si_shader_context *ctx,
  * Note that every attribute has 4 components.
  */
 static LLVMValueRef get_tcs_tes_buffer_address(struct si_shader_context *ctx,
+                                              LLVMValueRef rel_patch_id,
                                                LLVMValueRef vertex_index,
                                                LLVMValueRef param_index)
 {
@@ -729,7 +730,7 @@ static LLVMValueRef get_tcs_tes_buffer_address(struct si_shader_context *ctx,
 
        constant16 = lp_build_const_int32(gallivm, 16);
        if (vertex_index) {
-               base_addr = LLVMBuildMul(gallivm->builder, get_rel_patch_id(ctx),
+               base_addr = LLVMBuildMul(gallivm->builder, rel_patch_id,
                                         vertices_per_patch, "");
 
                base_addr = LLVMBuildAdd(gallivm->builder, base_addr,
@@ -737,7 +738,7 @@ static LLVMValueRef get_tcs_tes_buffer_address(struct si_shader_context *ctx,
 
                param_stride = total_vertices;
        } else {
-               base_addr = get_rel_patch_id(ctx);
+               base_addr = rel_patch_id;
                param_stride = num_patches;
        }
 
@@ -817,7 +818,8 @@ static LLVMValueRef get_tcs_tes_buffer_address_from_reg(
                                   lp_build_const_int32(gallivm, param_index_base),
                                   "");
 
-       return get_tcs_tes_buffer_address(ctx, vertex_index, param_index);
+       return get_tcs_tes_buffer_address(ctx, get_rel_patch_id(ctx),
+                                         vertex_index, param_index);
 }
 
 static LLVMValueRef buffer_load(struct lp_build_tgsi_context *bld_base,
@@ -988,6 +990,7 @@ static void store_output_tcs(struct lp_build_tgsi_context *bld_base,
        LLVMValueRef rw_buffers, buffer, base, buf_addr;
        LLVMValueRef values[4];
        bool skip_lds_store;
+       bool is_tess_factor = false;
 
        /* Only handle per-patch and per-vertex outputs here.
         * Vectors will be lowered to scalars and this function will be called again.
@@ -1013,8 +1016,10 @@ static void store_output_tcs(struct lp_build_tgsi_context *bld_base,
 
                        /* Always write tess factors into LDS for the TCS epilog. */
                        if (name == TGSI_SEMANTIC_TESSINNER ||
-                           name == TGSI_SEMANTIC_TESSOUTER)
+                           name == TGSI_SEMANTIC_TESSOUTER) {
                                skip_lds_store = false;
+                               is_tess_factor = true;
+                       }
                }
        }
 
@@ -1040,14 +1045,14 @@ static void store_output_tcs(struct lp_build_tgsi_context *bld_base,
                value = LLVMBuildBitCast(gallivm->builder, value, ctx->i32, "");
                values[chan_index] = value;
 
-               if (inst->Dst[0].Register.WriteMask != 0xF) {
+               if (inst->Dst[0].Register.WriteMask != 0xF && !is_tess_factor) {
                        ac_build_tbuffer_store_dwords(&ctx->ac, buffer, value, 1,
                                                      buf_addr, base,
                                                      4 * chan_index);
                }
        }
 
-       if (inst->Dst[0].Register.WriteMask == 0xF) {
+       if (inst->Dst[0].Register.WriteMask == 0xF && !is_tess_factor) {
                LLVMValueRef value = lp_build_gather_values(bld_base->base.gallivm,
                                                            values, 4);
                ac_build_tbuffer_store_dwords(&ctx->ac, buffer, value, 4, buf_addr,
@@ -1530,7 +1535,7 @@ static void declare_system_value(
                        lp_build_const_int32(gallivm, SI_HS_RING_TESS_OFFCHIP));
 
                base = LLVMGetParam(ctx->main_fn, ctx->param_oc_lds);
-               addr = get_tcs_tes_buffer_address(ctx, NULL,
+               addr = get_tcs_tes_buffer_address(ctx, get_rel_patch_id(ctx), NULL,
                                          lp_build_const_int32(gallivm, param));
 
                value = buffer_load(&radeon_bld->bld_base, TGSI_TYPE_FLOAT,
@@ -2422,6 +2427,7 @@ static void si_copy_tcs_inputs(struct lp_build_tgsi_context *bld_base)
                                             "");
 
                LLVMValueRef buffer_addr = get_tcs_tes_buffer_address(ctx,
+                                             get_rel_patch_id(ctx),
                                              invocation_id,
                                              lp_build_const_int32(gallivm, i));
 
@@ -2443,7 +2449,7 @@ static void si_write_tess_factors(struct lp_build_tgsi_context *bld_base,
        struct si_shader *shader = ctx->shader;
        unsigned tess_inner_index, tess_outer_index;
        LLVMValueRef lds_base, lds_inner, lds_outer, byteoffset, buffer;
-       LLVMValueRef out[6], vec0, vec1, rw_buffers, tf_base;
+       LLVMValueRef out[6], vec0, vec1, rw_buffers, tf_base, inner[4], outer[4];
        unsigned stride, outer_comps, inner_comps, i;
        struct lp_build_if_state if_ctx, inner_if_ctx;
 
@@ -2495,17 +2501,26 @@ static void si_write_tess_factors(struct lp_build_tgsi_context *bld_base,
                                 lp_build_const_int32(gallivm,
                                                      tess_outer_index * 4), "");
 
+       for (i = 0; i < 4; i++) {
+               inner[i] = LLVMGetUndef(ctx->i32);
+               outer[i] = LLVMGetUndef(ctx->i32);
+       }
+
        if (shader->key.part.tcs.epilog.prim_mode == PIPE_PRIM_LINES) {
                /* For isolines, the hardware expects tess factors in the
                 * reverse order from what GLSL / TGSI specify.
                 */
-               out[0] = lds_load(bld_base, TGSI_TYPE_SIGNED, 1, lds_outer);
-               out[1] = lds_load(bld_base, TGSI_TYPE_SIGNED, 0, lds_outer);
+               outer[0] = out[1] = lds_load(bld_base, TGSI_TYPE_SIGNED, 0, lds_outer);
+               outer[1] = out[0] = lds_load(bld_base, TGSI_TYPE_SIGNED, 1, lds_outer);
        } else {
-               for (i = 0; i < outer_comps; i++)
-                       out[i] = lds_load(bld_base, TGSI_TYPE_SIGNED, i, lds_outer);
-               for (i = 0; i < inner_comps; i++)
-                       out[outer_comps+i] = lds_load(bld_base, TGSI_TYPE_SIGNED, i, lds_inner);
+               for (i = 0; i < outer_comps; i++) {
+                       outer[i] = out[i] =
+                               lds_load(bld_base, TGSI_TYPE_SIGNED, i, lds_outer);
+               }
+               for (i = 0; i < inner_comps; i++) {
+                       inner[i] = out[outer_comps+i] =
+                               lds_load(bld_base, TGSI_TYPE_SIGNED, i, lds_inner);
+               }
        }
 
        /* Convert the outputs to vectors for stores. */
@@ -2544,6 +2559,42 @@ static void si_write_tess_factors(struct lp_build_tgsi_context *bld_base,
        if (vec1)
                ac_build_tbuffer_store_dwords(&ctx->ac, buffer, vec1,
                                              stride - 4, byteoffset, tf_base, 20);
+
+       /* Store the tess factors into the offchip buffer if TES reads them. */
+       if (shader->key.part.tcs.epilog.tes_reads_tess_factors) {
+               LLVMValueRef buf, base, inner_vec, outer_vec, tf_outer_offset;
+               LLVMValueRef tf_inner_offset;
+               unsigned param_outer, param_inner;
+
+               buf = ac_build_indexed_load_const(&ctx->ac, rw_buffers,
+                               LLVMConstInt(ctx->i32, SI_HS_RING_TESS_OFFCHIP, 0));
+               base = LLVMGetParam(ctx->main_fn, ctx->param_oc_lds);
+
+               param_outer = si_shader_io_get_unique_index(
+                                     TGSI_SEMANTIC_TESSOUTER, 0);
+               tf_outer_offset = get_tcs_tes_buffer_address(ctx, rel_patch_id, NULL,
+                                       LLVMConstInt(ctx->i32, param_outer, 0));
+
+               outer_vec = lp_build_gather_values(gallivm, outer,
+                                                  util_next_power_of_two(outer_comps));
+
+               ac_build_tbuffer_store_dwords(&ctx->ac, buf, outer_vec,
+                                             outer_comps, tf_outer_offset,
+                                             base, 0);
+               if (inner_comps) {
+                       param_inner = si_shader_io_get_unique_index(
+                                             TGSI_SEMANTIC_TESSINNER, 0);
+                       tf_inner_offset = get_tcs_tes_buffer_address(ctx, rel_patch_id, NULL,
+                                       LLVMConstInt(ctx->i32, param_inner, 0));
+
+                       inner_vec = inner_comps == 1 ? inner[0] :
+                                   lp_build_gather_values(gallivm, inner, inner_comps);
+                       ac_build_tbuffer_store_dwords(&ctx->ac, buf, inner_vec,
+                                                     inner_comps, tf_inner_offset,
+                                                     base, 0);
+               }
+       }
+
        lp_build_endif(&if_ctx);
 }
 
@@ -2552,6 +2603,7 @@ static void si_llvm_emit_tcs_epilogue(struct lp_build_tgsi_context *bld_base)
 {
        struct si_shader_context *ctx = si_shader_context(bld_base);
        LLVMValueRef rel_patch_id, invocation_id, tf_lds_offset;
+       LLVMValueRef offchip_soffset, offchip_layout;
 
        si_copy_tcs_inputs(bld_base);
 
@@ -2577,9 +2629,16 @@ static void si_llvm_emit_tcs_epilogue(struct lp_build_tgsi_context *bld_base)
        ret = LLVMBuildInsertValue(builder, ret, rw0, 0, "");
        ret = LLVMBuildInsertValue(builder, ret, rw1, 1, "");
 
-       /* Tess factor buffer soffset is after user SGPRs. */
+       /* Tess offchip and factor buffer soffset are after user SGPRs. */
+       offchip_layout = LLVMGetParam(ctx->main_fn,
+                                     SI_PARAM_TCS_OFFCHIP_LAYOUT);
+       offchip_soffset = LLVMGetParam(ctx->main_fn, ctx->param_oc_lds);
        tf_soffset = LLVMGetParam(ctx->main_fn,
                                  SI_PARAM_TESS_FACTOR_OFFSET);
+       ret = LLVMBuildInsertValue(builder, ret, offchip_layout,
+                                  SI_SGPR_TCS_OFFCHIP_LAYOUT, "");
+       ret = LLVMBuildInsertValue(builder, ret, offchip_soffset,
+                                  SI_TCS_NUM_USER_SGPR, "");
        ret = LLVMBuildInsertValue(builder, ret, tf_soffset,
                                   SI_TCS_NUM_USER_SGPR + 1, "");
 

diff --git a/src/gallium/drivers/radeonsi/si_shader.h b/src/gallium/drivers/radeonsi/si_shader.h
index 579f3ca2df67690ddb0d9d0e265b52d63d75c33c..fda8cc6508550c3fe41f7db7a87b2267e092b4b7 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader.h
+++ b/src/gallium/drivers/radeonsi/si_shader.h
@@ -352,6 +352,7 @@ struct si_vs_epilog_bits {
 /* Common TCS bits between the shader key and the epilog key. */
 struct si_tcs_epilog_bits {
        unsigned        prim_mode:3;
+       unsigned        tes_reads_tess_factors:1;
 };
 
 struct si_gs_prolog_bits {

diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
index d6d4560404f336578f4890fb3b202fc3a93e0a92..bcfff0c27709f76dcbe7bd3177532ba3718ebeed 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_state_shaders.c
+++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
@@ -992,6 +992,8 @@ static inline void si_shader_selector_key(struct pipe_context *ctx,
        case PIPE_SHADER_TESS_CTRL:
                key->part.tcs.epilog.prim_mode =
                        sctx->tes_shader.cso->info.properties[TGSI_PROPERTY_TES_PRIM_MODE];
+               key->part.tcs.epilog.tes_reads_tess_factors =
+                       sctx->tes_shader.cso->info.reads_tess_factors;
 
                if (sel == sctx->fixed_func_tcs_shader.cso)
                        key->mono.tcs.inputs_to_copy = sctx->vs_shader.cso->outputs_written;