1 /*
2 * Copyright © 2014-2015 Broadcom
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 "nir.h"
25 #include "nir_builder.h"
26
27 /** @file nir_lower_alu_to_scalar.c
28 *
29 * Replaces nir_alu_instr operations with more than one channel used in the
30 * arguments with individual per-channel operations.
31 */
32
33 static void
nir_alu_ssa_dest_init(nir_alu_instr * instr,unsigned num_components,unsigned bit_size)34 nir_alu_ssa_dest_init(nir_alu_instr *instr, unsigned num_components,
35 unsigned bit_size)
36 {
37 nir_ssa_dest_init(&instr->instr, &instr->dest.dest, num_components,
38 bit_size, NULL);
39 instr->dest.write_mask = (1 << num_components) - 1;
40 }
41
42 static void
lower_reduction(nir_alu_instr * instr,nir_op chan_op,nir_op merge_op,nir_builder * builder)43 lower_reduction(nir_alu_instr *instr, nir_op chan_op, nir_op merge_op,
44 nir_builder *builder)
45 {
46 unsigned num_components = nir_op_infos[instr->op].input_sizes[0];
47
48 nir_ssa_def *last = NULL;
49 for (unsigned i = 0; i < num_components; i++) {
50 nir_alu_instr *chan = nir_alu_instr_create(builder->shader, chan_op);
51 nir_alu_ssa_dest_init(chan, 1, instr->dest.dest.ssa.bit_size);
52 nir_alu_src_copy(&chan->src[0], &instr->src[0], chan);
53 chan->src[0].swizzle[0] = chan->src[0].swizzle[i];
54 if (nir_op_infos[chan_op].num_inputs > 1) {
55 assert(nir_op_infos[chan_op].num_inputs == 2);
56 nir_alu_src_copy(&chan->src[1], &instr->src[1], chan);
57 chan->src[1].swizzle[0] = chan->src[1].swizzle[i];
58 }
59 chan->exact = instr->exact;
60
61 nir_builder_instr_insert(builder, &chan->instr);
62
63 if (i == 0) {
64 last = &chan->dest.dest.ssa;
65 } else {
66 last = nir_build_alu(builder, merge_op,
67 last, &chan->dest.dest.ssa, NULL, NULL);
68 }
69 }
70
71 assert(instr->dest.write_mask == 1);
72 nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(last));
73 nir_instr_remove(&instr->instr);
74 }
75
76 static bool
lower_alu_instr_scalar(nir_alu_instr * instr,nir_builder * b)77 lower_alu_instr_scalar(nir_alu_instr *instr, nir_builder *b)
78 {
79 unsigned num_src = nir_op_infos[instr->op].num_inputs;
80 unsigned i, chan;
81
82 assert(instr->dest.dest.is_ssa);
83 assert(instr->dest.write_mask != 0);
84
85 b->cursor = nir_before_instr(&instr->instr);
86 b->exact = instr->exact;
87
88 #define LOWER_REDUCTION(name, chan, merge) \
89 case name##2: \
90 case name##3: \
91 case name##4: \
92 lower_reduction(instr, chan, merge, b); \
93 return true;
94
95 switch (instr->op) {
96 case nir_op_vec4:
97 case nir_op_vec3:
98 case nir_op_vec2:
99 /* We don't need to scalarize these ops, they're the ones generated to
100 * group up outputs into a value that can be SSAed.
101 */
102 return false;
103
104 case nir_op_pack_half_2x16:
105 if (!b->shader->options->lower_pack_half_2x16)
106 return false;
107
108 nir_ssa_def *val =
109 nir_pack_half_2x16_split(b, nir_channel(b, instr->src[0].src.ssa,
110 instr->src[0].swizzle[0]),
111 nir_channel(b, instr->src[0].src.ssa,
112 instr->src[0].swizzle[1]));
113
114 nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
115 nir_instr_remove(&instr->instr);
116 return true;
117
118 case nir_op_unpack_unorm_4x8:
119 case nir_op_unpack_snorm_4x8:
120 case nir_op_unpack_unorm_2x16:
121 case nir_op_unpack_snorm_2x16:
122 /* There is no scalar version of these ops, unless we were to break it
123 * down to bitshifts and math (which is definitely not intended).
124 */
125 return false;
126
127 case nir_op_unpack_half_2x16: {
128 if (!b->shader->options->lower_unpack_half_2x16)
129 return false;
130
131 nir_ssa_def *comps[2];
132 comps[0] = nir_unpack_half_2x16_split_x(b, instr->src[0].src.ssa);
133 comps[1] = nir_unpack_half_2x16_split_y(b, instr->src[0].src.ssa);
134 nir_ssa_def *vec = nir_vec(b, comps, 2);
135
136 nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(vec));
137 nir_instr_remove(&instr->instr);
138 return true;
139 }
140
141 case nir_op_pack_uvec2_to_uint: {
142 assert(b->shader->options->lower_pack_snorm_2x16 ||
143 b->shader->options->lower_pack_unorm_2x16);
144
145 nir_ssa_def *word =
146 nir_extract_u16(b, instr->src[0].src.ssa, nir_imm_int(b, 0));
147 nir_ssa_def *val =
148 nir_ior(b, nir_ishl(b, nir_channel(b, word, 1), nir_imm_int(b, 16)),
149 nir_channel(b, word, 0));
150
151 nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
152 nir_instr_remove(&instr->instr);
153 break;
154 }
155
156 case nir_op_pack_uvec4_to_uint: {
157 assert(b->shader->options->lower_pack_snorm_4x8 ||
158 b->shader->options->lower_pack_unorm_4x8);
159
160 nir_ssa_def *byte =
161 nir_extract_u8(b, instr->src[0].src.ssa, nir_imm_int(b, 0));
162 nir_ssa_def *val =
163 nir_ior(b, nir_ior(b, nir_ishl(b, nir_channel(b, byte, 3), nir_imm_int(b, 24)),
164 nir_ishl(b, nir_channel(b, byte, 2), nir_imm_int(b, 16))),
165 nir_ior(b, nir_ishl(b, nir_channel(b, byte, 1), nir_imm_int(b, 8)),
166 nir_channel(b, byte, 0)));
167
168 nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
169 nir_instr_remove(&instr->instr);
170 break;
171 }
172
173 case nir_op_fdph: {
174 nir_ssa_def *sum[4];
175 for (unsigned i = 0; i < 3; i++) {
176 sum[i] = nir_fmul(b, nir_channel(b, instr->src[0].src.ssa,
177 instr->src[0].swizzle[i]),
178 nir_channel(b, instr->src[1].src.ssa,
179 instr->src[1].swizzle[i]));
180 }
181 sum[3] = nir_channel(b, instr->src[1].src.ssa, instr->src[1].swizzle[3]);
182
183 nir_ssa_def *val = nir_fadd(b, nir_fadd(b, sum[0], sum[1]),
184 nir_fadd(b, sum[2], sum[3]));
185
186 nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
187 nir_instr_remove(&instr->instr);
188 return true;
189 }
190
191 case nir_op_unpack_double_2x32:
192 return false;
193
194 LOWER_REDUCTION(nir_op_fdot, nir_op_fmul, nir_op_fadd);
195 LOWER_REDUCTION(nir_op_ball_fequal, nir_op_feq, nir_op_iand);
196 LOWER_REDUCTION(nir_op_ball_iequal, nir_op_ieq, nir_op_iand);
197 LOWER_REDUCTION(nir_op_bany_fnequal, nir_op_fne, nir_op_ior);
198 LOWER_REDUCTION(nir_op_bany_inequal, nir_op_ine, nir_op_ior);
199 LOWER_REDUCTION(nir_op_fall_equal, nir_op_seq, nir_op_fand);
200 LOWER_REDUCTION(nir_op_fany_nequal, nir_op_sne, nir_op_for);
201
202 default:
203 break;
204 }
205
206 if (instr->dest.dest.ssa.num_components == 1)
207 return false;
208
209 unsigned num_components = instr->dest.dest.ssa.num_components;
210 nir_ssa_def *comps[] = { NULL, NULL, NULL, NULL };
211
212 for (chan = 0; chan < 4; chan++) {
213 if (!(instr->dest.write_mask & (1 << chan)))
214 continue;
215
216 nir_alu_instr *lower = nir_alu_instr_create(b->shader, instr->op);
217 for (i = 0; i < num_src; i++) {
218 /* We only handle same-size-as-dest (input_sizes[] == 0) or scalar
219 * args (input_sizes[] == 1).
220 */
221 assert(nir_op_infos[instr->op].input_sizes[i] < 2);
222 unsigned src_chan = (nir_op_infos[instr->op].input_sizes[i] == 1 ?
223 0 : chan);
224
225 nir_alu_src_copy(&lower->src[i], &instr->src[i], lower);
226 for (int j = 0; j < 4; j++)
227 lower->src[i].swizzle[j] = instr->src[i].swizzle[src_chan];
228 }
229
230 nir_alu_ssa_dest_init(lower, 1, instr->dest.dest.ssa.bit_size);
231 lower->dest.saturate = instr->dest.saturate;
232 comps[chan] = &lower->dest.dest.ssa;
233 lower->exact = instr->exact;
234
235 nir_builder_instr_insert(b, &lower->instr);
236 }
237
238 nir_ssa_def *vec = nir_vec(b, comps, num_components);
239
240 nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(vec));
241
242 nir_instr_remove(&instr->instr);
243 return true;
244 }
245
246 static bool
nir_lower_alu_to_scalar_impl(nir_function_impl * impl)247 nir_lower_alu_to_scalar_impl(nir_function_impl *impl)
248 {
249 nir_builder builder;
250 nir_builder_init(&builder, impl);
251 bool progress = false;
252
253 nir_foreach_block(block, impl) {
254 nir_foreach_instr_safe(instr, block) {
255 if (instr->type == nir_instr_type_alu) {
256 progress = lower_alu_instr_scalar(nir_instr_as_alu(instr),
257 &builder) || progress;
258 }
259 }
260 }
261
262 nir_metadata_preserve(impl, nir_metadata_block_index |
263 nir_metadata_dominance);
264
265 return progress;
266 }
267
268 bool
nir_lower_alu_to_scalar(nir_shader * shader)269 nir_lower_alu_to_scalar(nir_shader *shader)
270 {
271 bool progress = false;
272
273 nir_foreach_function(function, shader) {
274 if (function->impl)
275 progress = nir_lower_alu_to_scalar_impl(function->impl) || progress;
276 }
277
278 return progress;
279 }
280