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 nir_function_impl *impl;
30 bool progress;
31 nir_builder builder;
32 };
33
34 static bool
lower_cs_intrinsics_convert_block(struct lower_intrinsics_state * state,nir_block * block)35 lower_cs_intrinsics_convert_block(struct lower_intrinsics_state *state,
36 nir_block *block)
37 {
38 bool progress = false;
39 nir_builder *b = &state->builder;
40 nir_shader *nir = state->nir;
41
42 /* Reuse calculated values inside the block. */
43 nir_ssa_def *local_index = NULL;
44 nir_ssa_def *local_id = NULL;
45
46 nir_foreach_instr_safe(instr, block) {
47 if (instr->type != nir_instr_type_intrinsic)
48 continue;
49
50 nir_intrinsic_instr *intrinsic = nir_instr_as_intrinsic(instr);
51
52 b->cursor = nir_after_instr(&intrinsic->instr);
53
54 nir_ssa_def *sysval;
55 switch (intrinsic->intrinsic) {
56 case nir_intrinsic_load_workgroup_size:
57 case nir_intrinsic_load_workgroup_id:
58 case nir_intrinsic_load_num_workgroups:
59 /* Convert this to 32-bit if it's not */
60 if (intrinsic->dest.ssa.bit_size == 64) {
61 intrinsic->dest.ssa.bit_size = 32;
62 sysval = nir_u2u64(b, &intrinsic->dest.ssa);
63 nir_ssa_def_rewrite_uses_after(&intrinsic->dest.ssa,
64 sysval,
65 sysval->parent_instr);
66 }
67 continue;
68
69 case nir_intrinsic_load_local_invocation_index:
70 case nir_intrinsic_load_local_invocation_id: {
71 if (nir->info.stage == MESA_SHADER_TASK ||
72 nir->info.stage == MESA_SHADER_MESH) {
73 /* Will be lowered by nir_emit_task_mesh_intrinsic() using
74 * information from the payload.
75 */
76 continue;
77 }
78
79 /* First time we are using those, so let's calculate them. */
80 if (!local_index) {
81 assert(!local_id);
82
83 nir_ssa_def *subgroup_id = nir_load_subgroup_id(b);
84
85 nir_ssa_def *thread_local_id =
86 nir_imul(b, subgroup_id, nir_load_simd_width_intel(b));
87 nir_ssa_def *channel = nir_load_subgroup_invocation(b);
88 nir_ssa_def *linear = nir_iadd(b, channel, thread_local_id);
89
90 nir_ssa_def *size_x;
91 nir_ssa_def *size_y;
92 if (state->nir->info.workgroup_size_variable) {
93 nir_ssa_def *size_xyz = nir_load_workgroup_size(b);
94 size_x = nir_channel(b, size_xyz, 0);
95 size_y = nir_channel(b, size_xyz, 1);
96 } else {
97 size_x = nir_imm_int(b, nir->info.workgroup_size[0]);
98 size_y = nir_imm_int(b, nir->info.workgroup_size[1]);
99 }
100 nir_ssa_def *size_xy = nir_imul(b, size_x, size_y);
101
102 /* The local invocation index and ID must respect the following
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 * However, the final % gl_WorkGroupSize.z does nothing unless we
115 * accidentally end up with a gl_LocalInvocationIndex that is too
116 * large so it can safely be omitted.
117 */
118
119 nir_ssa_def *id_x, *id_y, *id_z;
120 switch (state->nir->info.cs.derivative_group) {
121 case DERIVATIVE_GROUP_NONE:
122 if (nir->info.num_images == 0 &&
123 nir->info.num_textures == 0) {
124 /* X-major lid order. Optimal for linear accesses only,
125 * which are usually buffers. X,Y ordering will look like:
126 * (0,0) (1,0) (2,0) ... (size_x-1,0) (0,1) (1,1) ...
127 */
128 id_x = nir_umod(b, linear, size_x);
129 id_y = nir_umod(b, nir_udiv(b, linear, size_x), size_y);
130 local_index = linear;
131 } else if (!nir->info.workgroup_size_variable &&
132 nir->info.workgroup_size[1] % 4 == 0) {
133 /* 1x4 block X-major lid order. Same as X-major except increments in
134 * blocks of width=1 height=4. Always optimal for tileY and usually
135 * optimal for linear accesses.
136 * x = (linear / 4) % size_x
137 * y = ((linear % 4) + (linear / 4 / size_x) * 4) % size_y
138 * X,Y ordering will look like: (0,0) (0,1) (0,2) (0,3) (1,0) (1,1)
139 * (1,2) (1,3) (2,0) ... (size_x-1,3) (0,4) (0,5) (0,6) (0,7) (1,4) ...
140 */
141 const unsigned height = 4;
142 nir_ssa_def *block = nir_udiv_imm(b, linear, height);
143 id_x = nir_umod(b, block, size_x);
144 id_y = nir_umod(b,
145 nir_iadd(b,
146 nir_umod(b, linear, nir_imm_int(b, height)),
147 nir_imul_imm(b,
148 nir_udiv(b, block, size_x),
149 height)),
150 size_y);
151 } else {
152 /* Y-major lid order. Optimal for tileY accesses only,
153 * which are usually images. X,Y ordering will look like:
154 * (0,0) (0,1) (0,2) ... (0,size_y-1) (1,0) (1,1) ...
155 */
156 id_y = nir_umod(b, linear, size_y);
157 id_x = nir_umod(b, nir_udiv(b, linear, size_y), size_x);
158 }
159
160 id_z = nir_udiv(b, linear, size_xy);
161 local_id = nir_vec3(b, id_x, id_y, id_z);
162 if (!local_index) {
163 local_index = nir_iadd(b, nir_iadd(b, id_x,
164 nir_imul(b, id_y, size_x)),
165 nir_imul(b, id_z, size_xy));
166 }
167 break;
168 case DERIVATIVE_GROUP_LINEAR:
169 /* For linear, just set the local invocation index linearly,
170 * and calculate local invocation ID from that.
171 */
172 id_x = nir_umod(b, linear, size_x);
173 id_y = nir_umod(b, nir_udiv(b, linear, size_x), size_y);
174 id_z = nir_udiv(b, linear, size_xy);
175 local_id = nir_vec3(b, id_x, id_y, id_z);
176 local_index = linear;
177 break;
178 case DERIVATIVE_GROUP_QUADS: {
179 /* For quads, first we figure out the 2x2 grid the invocation
180 * belongs to -- treating extra Z layers as just more rows.
181 * Then map that into local invocation ID (trivial) and local
182 * invocation index. Skipping Z simplify index calculation.
183 */
184
185 nir_ssa_def *one = nir_imm_int(b, 1);
186 nir_ssa_def *double_size_x = nir_ishl(b, size_x, one);
187
188 /* ID within a pair of rows, where each group of 4 is 2x2 quad. */
189 nir_ssa_def *row_pair_id = nir_umod(b, linear, double_size_x);
190 nir_ssa_def *y_row_pairs = nir_udiv(b, linear, double_size_x);
191
192 nir_ssa_def *x =
193 nir_ior(b,
194 nir_iand(b, row_pair_id, one),
195 nir_iand(b, nir_ishr(b, row_pair_id, one),
196 nir_imm_int(b, 0xfffffffe)));
197 nir_ssa_def *y =
198 nir_ior(b,
199 nir_ishl(b, y_row_pairs, one),
200 nir_iand(b, nir_ishr(b, row_pair_id, one), one));
201
202 local_id = nir_vec3(b, x,
203 nir_umod(b, y, size_y),
204 nir_udiv(b, y, size_y));
205 local_index = nir_iadd(b, x, nir_imul(b, y, size_x));
206 break;
207 }
208 default:
209 unreachable("invalid derivative group");
210 }
211 }
212
213 assert(local_id);
214 assert(local_index);
215 if (intrinsic->intrinsic == nir_intrinsic_load_local_invocation_id)
216 sysval = local_id;
217 else
218 sysval = local_index;
219 break;
220 }
221
222 case nir_intrinsic_load_num_subgroups: {
223 nir_ssa_def *size;
224 if (state->nir->info.workgroup_size_variable) {
225 nir_ssa_def *size_xyz = nir_load_workgroup_size(b);
226 nir_ssa_def *size_x = nir_channel(b, size_xyz, 0);
227 nir_ssa_def *size_y = nir_channel(b, size_xyz, 1);
228 nir_ssa_def *size_z = nir_channel(b, size_xyz, 2);
229 size = nir_imul(b, nir_imul(b, size_x, size_y), size_z);
230 } else {
231 size = nir_imm_int(b, nir->info.workgroup_size[0] *
232 nir->info.workgroup_size[1] *
233 nir->info.workgroup_size[2]);
234 }
235
236 /* Calculate the equivalent of DIV_ROUND_UP. */
237 nir_ssa_def *simd_width = nir_load_simd_width_intel(b);
238 sysval =
239 nir_udiv(b, nir_iadd_imm(b, nir_iadd(b, size, simd_width), -1),
240 simd_width);
241 break;
242 }
243
244 default:
245 continue;
246 }
247
248 if (intrinsic->dest.ssa.bit_size == 64)
249 sysval = nir_u2u64(b, sysval);
250
251 nir_ssa_def_rewrite_uses(&intrinsic->dest.ssa, sysval);
252 nir_instr_remove(&intrinsic->instr);
253
254 state->progress = true;
255 }
256
257 return progress;
258 }
259
260 static void
lower_cs_intrinsics_convert_impl(struct lower_intrinsics_state * state)261 lower_cs_intrinsics_convert_impl(struct lower_intrinsics_state *state)
262 {
263 nir_builder_init(&state->builder, state->impl);
264
265 nir_foreach_block(block, state->impl) {
266 lower_cs_intrinsics_convert_block(state, block);
267 }
268
269 nir_metadata_preserve(state->impl,
270 nir_metadata_block_index | nir_metadata_dominance);
271 }
272
273 bool
brw_nir_lower_cs_intrinsics(nir_shader * nir)274 brw_nir_lower_cs_intrinsics(nir_shader *nir)
275 {
276 assert(gl_shader_stage_uses_workgroup(nir->info.stage));
277
278 struct lower_intrinsics_state state = {
279 .nir = nir,
280 };
281
282 /* Constraints from NV_compute_shader_derivatives. */
283 if (gl_shader_stage_is_compute(nir->info.stage) &&
284 !nir->info.workgroup_size_variable) {
285 if (nir->info.cs.derivative_group == DERIVATIVE_GROUP_QUADS) {
286 assert(nir->info.workgroup_size[0] % 2 == 0);
287 assert(nir->info.workgroup_size[1] % 2 == 0);
288 } else if (nir->info.cs.derivative_group == DERIVATIVE_GROUP_LINEAR) {
289 ASSERTED unsigned workgroup_size =
290 nir->info.workgroup_size[0] *
291 nir->info.workgroup_size[1] *
292 nir->info.workgroup_size[2];
293 assert(workgroup_size % 4 == 0);
294 }
295 }
296
297 nir_foreach_function(function, nir) {
298 if (function->impl) {
299 state.impl = function->impl;
300 lower_cs_intrinsics_convert_impl(&state);
301 }
302 }
303
304 return state.progress;
305 }
306