1 /*
2 * Copyright (c) 2016 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24 #include "brw_nir.h"
25 #include "compiler/nir/nir_builder.h"
26
27 struct lower_intrinsics_state {
28 nir_shader *nir;
29 union {
30 struct brw_stage_prog_data *prog_data;
31 struct brw_cs_prog_data *cs_prog_data;
32 };
33 nir_function_impl *impl;
34 bool progress;
35 nir_builder builder;
36 bool cs_thread_id_used;
37 };
38
39 static nir_ssa_def *
read_thread_local_id(struct lower_intrinsics_state * state)40 read_thread_local_id(struct lower_intrinsics_state *state)
41 {
42 nir_builder *b = &state->builder;
43 nir_shader *nir = state->nir;
44 const unsigned *sizes = nir->info->cs.local_size;
45 const unsigned group_size = sizes[0] * sizes[1] * sizes[2];
46
47 /* Some programs have local_size dimensions so small that the thread local
48 * ID will always be 0.
49 */
50 if (group_size <= 8)
51 return nir_imm_int(b, 0);
52
53 assert(state->cs_prog_data->thread_local_id_index >= 0);
54 state->cs_thread_id_used = true;
55 const int id_index = state->cs_prog_data->thread_local_id_index;
56
57 nir_intrinsic_instr *load =
58 nir_intrinsic_instr_create(nir, nir_intrinsic_load_uniform);
59 load->num_components = 1;
60 load->src[0] = nir_src_for_ssa(nir_imm_int(b, 0));
61 nir_ssa_dest_init(&load->instr, &load->dest, 1, 32, NULL);
62 nir_intrinsic_set_base(load, id_index * sizeof(uint32_t));
63 nir_intrinsic_set_range(load, sizeof(uint32_t));
64 nir_builder_instr_insert(b, &load->instr);
65 return &load->dest.ssa;
66 }
67
68 static bool
lower_cs_intrinsics_convert_block(struct lower_intrinsics_state * state,nir_block * block)69 lower_cs_intrinsics_convert_block(struct lower_intrinsics_state *state,
70 nir_block *block)
71 {
72 bool progress = false;
73 nir_builder *b = &state->builder;
74 nir_shader *nir = state->nir;
75
76 nir_foreach_instr_safe(instr, block) {
77 if (instr->type != nir_instr_type_intrinsic)
78 continue;
79
80 nir_intrinsic_instr *intrinsic = nir_instr_as_intrinsic(instr);
81
82 b->cursor = nir_after_instr(&intrinsic->instr);
83
84 nir_ssa_def *sysval;
85 switch (intrinsic->intrinsic) {
86 case nir_intrinsic_load_local_invocation_index: {
87 assert(nir->stage == MESA_SHADER_COMPUTE);
88 /* We construct the local invocation index from:
89 *
90 * gl_LocalInvocationIndex =
91 * cs_thread_local_id + channel_num;
92 */
93 nir_ssa_def *thread_local_id = read_thread_local_id(state);
94 nir_ssa_def *channel = nir_load_channel_num(b);
95 sysval = nir_iadd(b, channel, thread_local_id);
96 break;
97 }
98
99 case nir_intrinsic_load_local_invocation_id: {
100 assert(nir->stage == MESA_SHADER_COMPUTE);
101 /* We lower gl_LocalInvocationID from gl_LocalInvocationIndex based
102 * on this formula:
103 *
104 * gl_LocalInvocationID.x =
105 * gl_LocalInvocationIndex % gl_WorkGroupSize.x;
106 * gl_LocalInvocationID.y =
107 * (gl_LocalInvocationIndex / gl_WorkGroupSize.x) %
108 * gl_WorkGroupSize.y;
109 * gl_LocalInvocationID.z =
110 * (gl_LocalInvocationIndex /
111 * (gl_WorkGroupSize.x * gl_WorkGroupSize.y)) %
112 * gl_WorkGroupSize.z;
113 */
114 unsigned *size = nir->info->cs.local_size;
115
116 nir_ssa_def *local_index = nir_load_local_invocation_index(b);
117
118 nir_const_value uvec3;
119 uvec3.u32[0] = 1;
120 uvec3.u32[1] = size[0];
121 uvec3.u32[2] = size[0] * size[1];
122 nir_ssa_def *div_val = nir_build_imm(b, 3, 32, uvec3);
123 uvec3.u32[0] = size[0];
124 uvec3.u32[1] = size[1];
125 uvec3.u32[2] = size[2];
126 nir_ssa_def *mod_val = nir_build_imm(b, 3, 32, uvec3);
127
128 sysval = nir_umod(b, nir_udiv(b, local_index, div_val), mod_val);
129 break;
130 }
131
132 default:
133 continue;
134 }
135
136 nir_ssa_def_rewrite_uses(&intrinsic->dest.ssa, nir_src_for_ssa(sysval));
137 nir_instr_remove(&intrinsic->instr);
138
139 state->progress = true;
140 }
141
142 return progress;
143 }
144
145 static void
lower_cs_intrinsics_convert_impl(struct lower_intrinsics_state * state)146 lower_cs_intrinsics_convert_impl(struct lower_intrinsics_state *state)
147 {
148 nir_builder_init(&state->builder, state->impl);
149
150 nir_foreach_block(block, state->impl) {
151 lower_cs_intrinsics_convert_block(state, block);
152 }
153
154 nir_metadata_preserve(state->impl,
155 nir_metadata_block_index | nir_metadata_dominance);
156 }
157
158 bool
brw_nir_lower_intrinsics(nir_shader * nir,struct brw_stage_prog_data * prog_data)159 brw_nir_lower_intrinsics(nir_shader *nir, struct brw_stage_prog_data *prog_data)
160 {
161 /* Currently we only lower intrinsics for compute shaders */
162 if (nir->stage != MESA_SHADER_COMPUTE)
163 return false;
164
165 bool progress = false;
166 struct lower_intrinsics_state state;
167 memset(&state, 0, sizeof(state));
168 state.nir = nir;
169 state.prog_data = prog_data;
170
171 do {
172 state.progress = false;
173 nir_foreach_function(function, nir) {
174 if (function->impl) {
175 state.impl = function->impl;
176 lower_cs_intrinsics_convert_impl(&state);
177 }
178 }
179 progress |= state.progress;
180 } while (state.progress);
181
182 if (nir->stage == MESA_SHADER_COMPUTE && !state.cs_thread_id_used)
183 state.cs_prog_data->thread_local_id_index = -1;
184
185 return progress;
186 }
187