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1/*
2 * Copyright © 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/*
25 * This lowering pass converts references to variables with loads/stores to
26 * scratch space based on a few configurable parameters.
27 */
28
29#include "nir.h"
30#include "nir_builder.h"
31#include "nir_deref.h"
32
33static void
34lower_load_store(nir_builder *b,
35 nir_intrinsic_instr *intrin,
36 glsl_type_size_align_func size_align)
37{
38 b->cursor = nir_before_instr(&intrin->instr);
39
40 nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
41 nir_variable *var = nir_deref_instr_get_variable(deref);
42
43 nir_def *offset =
44 nir_iadd_imm(b, nir_build_deref_offset(b, deref, size_align),
45 var->data.location);
46
47 unsigned align, UNUSED size;
48 size_align(deref->type, &size, &align);
49
50 if (intrin->intrinsic == nir_intrinsic_load_deref) {
51 unsigned bit_size = intrin->def.bit_size;
52 nir_def *value = nir_load_scratch(
53 b, intrin->num_components, bit_size == 1 ? 32 : bit_size, offset, .align_mul = align);
54 if (bit_size == 1)
55 value = nir_b2b1(b, value);
56
57 nir_def_rewrite_uses(&intrin->def, value);
58 } else {
59 assert(intrin->intrinsic == nir_intrinsic_store_deref);
60
61 nir_def *value = intrin->src[1].ssa;
62 if (value->bit_size == 1)
63 value = nir_b2b32(b, value);
64
65 nir_store_scratch(b, value, offset, .align_mul = align,
66 .write_mask = nir_intrinsic_write_mask(intrin));
67 }
68
69 nir_instr_remove(&intrin->instr);
70 nir_deref_instr_remove_if_unused(deref);
71}
72
73static bool
74only_used_for_load_store(nir_deref_instr *deref)
75{
76 nir_foreach_use(src, &deref->def) {
77 if (!nir_src_parent_instr(src))
78 return false;
79 if (nir_src_parent_instr(src)->type == nir_instr_type_deref) {
80 if (!only_used_for_load_store(nir_instr_as_deref(nir_src_parent_instr(src))))
81 return false;
82 } else if (nir_src_parent_instr(src)->type != nir_instr_type_intrinsic) {
83 return false;
84 } else {
85 nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(nir_src_parent_instr(src));
86 if (intrin->intrinsic != nir_intrinsic_load_deref &&
87 intrin->intrinsic != nir_intrinsic_store_deref)
88 return false;
89 }
90 }
91 return true;
92}
93
94bool
95nir_lower_vars_to_scratch(nir_shader *shader,
96 nir_variable_mode modes,
97 int size_threshold,
98 glsl_type_size_align_func variable_size_align,
99 glsl_type_size_align_func scratch_layout_size_align)
100{
101 struct set *set = _mesa_pointer_set_create(NULL);
102
103 /* First, we walk the instructions and flag any variables we want to lower
104 * by removing them from their respective list and setting the mode to 0.
105 */
106 nir_foreach_function_impl(impl, shader) {
107 nir_foreach_block(block, impl) {
108 nir_foreach_instr(instr, block) {
109 if (instr->type != nir_instr_type_intrinsic)
110 continue;
111
112 nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
113 if (intrin->intrinsic != nir_intrinsic_load_deref &&
114 intrin->intrinsic != nir_intrinsic_store_deref)
115 continue;
116
117 nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
118 if (!nir_deref_mode_is_one_of(deref, modes))
119 continue;
120
121 if (!nir_deref_instr_has_indirect(nir_src_as_deref(intrin->src[0])))
122 continue;
123
124 nir_variable *var = nir_deref_instr_get_variable(deref);
125 if (!var)
126 continue;
127
128 /* We set var->mode to 0 to indicate that a variable will be moved
129 * to scratch. Don't assign a scratch location twice.
130 */
131 if (var->data.mode == 0)
132 continue;
133
134 unsigned var_size, var_align;
135 variable_size_align(var->type, &var_size, &var_align);
136 if (var_size <= size_threshold)
137 continue;
138
139 _mesa_set_add(set, var);
140 }
141 }
142 }
143
144 if (set->entries == 0) {
145 _mesa_set_destroy(set, NULL);
146 return false;
147 }
148
149 bool progress = false;
150
151 nir_foreach_function_impl(impl, shader) {
152 nir_foreach_block(block, impl) {
153 nir_foreach_instr_safe(instr, block) {
154 if (instr->type != nir_instr_type_deref)
155 continue;
156
157 nir_deref_instr *deref = nir_instr_as_deref(instr);
158
159 if (nir_deref_instr_remove_if_unused(deref)) {
160 progress = true;
161 continue;
162 }
163
164 if (deref->deref_type != nir_deref_type_var)
165 continue;
166
167 struct set_entry *entry = _mesa_set_search(set, deref->var);
168 if (!entry)
169 continue;
170
171 if (!only_used_for_load_store(deref))
172 _mesa_set_remove(set, entry);
173 }
174 }
175 }
176
177 set_foreach(set, entry) {
178 nir_variable *var = (void *)entry->key;
179
180 /* Remove it from its list */
181 exec_node_remove(&var->node);
182 /* Invalid mode used to flag "moving to scratch" */
183 var->data.mode = 0;
184
185 /* We don't allocate space here as iteration in this loop is
186 * non-deterministic due to the nir_variable pointers. */
187 var->data.location = INT_MAX;
188 }
189
190 nir_foreach_function_impl(impl, shader) {
191 nir_builder build = nir_builder_create(impl);
192
193 bool impl_progress = false;
194 nir_foreach_block(block, impl) {
195 nir_foreach_instr_safe(instr, block) {
196 if (instr->type != nir_instr_type_intrinsic)
197 continue;
198
199 nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
200 if (intrin->intrinsic != nir_intrinsic_load_deref &&
201 intrin->intrinsic != nir_intrinsic_store_deref)
202 continue;
203
204 nir_variable *var = nir_intrinsic_get_var(intrin, 0);
205 /* Variables flagged for lowering above have mode == 0 */
206 if (!var || var->data.mode)
207 continue;
208
209 if (var->data.location == INT_MAX) {
210 unsigned var_size, var_align;
211 scratch_layout_size_align(var->type, &var_size, &var_align);
212
213 var->data.location = ALIGN_POT(shader->scratch_size, var_align);
214 shader->scratch_size = var->data.location + var_size;
215 }
216
217 lower_load_store(&build, intrin, scratch_layout_size_align);
218 impl_progress = true;
219 }
220 }
221
222 if (impl_progress) {
223 progress = true;
224 nir_metadata_preserve(impl, nir_metadata_control_flow);
225 } else {
226 nir_metadata_preserve(impl, nir_metadata_all);
227 }
228 }
229
230 _mesa_set_destroy(set, NULL);
231
232 return progress;
233}