nir: Handle all array stride cases in nir_deref_instr_array_stride
[mesa.git] / src / compiler / nir / nir_repair_ssa.c
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 #include "nir.h"
25 #include "nir_phi_builder.h"
26
27 struct repair_ssa_state {
28 nir_function_impl *impl;
29
30 BITSET_WORD *def_set;
31 struct nir_phi_builder *phi_builder;
32
33 bool progress;
34 };
35
36 /* Get ready to build a phi and return the builder */
37 static struct nir_phi_builder *
38 prep_build_phi(struct repair_ssa_state *state)
39 {
40 const unsigned num_words = BITSET_WORDS(state->impl->num_blocks);
41
42 /* We create the phi builder on-demand. */
43 if (state->phi_builder == NULL) {
44 state->phi_builder = nir_phi_builder_create(state->impl);
45 state->def_set = ralloc_array(NULL, BITSET_WORD, num_words);
46 }
47
48 /* We're going to build a phi. That's progress. */
49 state->progress = true;
50
51 /* Set the defs set to empty */
52 memset(state->def_set, 0, num_words * sizeof(*state->def_set));
53
54 return state->phi_builder;
55 }
56
57 static nir_block *
58 get_src_block(nir_src *src)
59 {
60 if (src->parent_instr->type == nir_instr_type_phi) {
61 return exec_node_data(nir_phi_src, src, src)->pred;
62 } else {
63 return src->parent_instr->block;
64 }
65 }
66
67 static bool
68 repair_ssa_def(nir_ssa_def *def, void *void_state)
69 {
70 struct repair_ssa_state *state = void_state;
71
72 bool is_valid = true;
73 nir_foreach_use(src, def) {
74 if (nir_block_is_unreachable(get_src_block(src)) ||
75 !nir_block_dominates(def->parent_instr->block, get_src_block(src))) {
76 is_valid = false;
77 break;
78 }
79 }
80
81 nir_foreach_if_use(src, def) {
82 nir_block *block_before_if =
83 nir_cf_node_as_block(nir_cf_node_prev(&src->parent_if->cf_node));
84 if (nir_block_is_unreachable(block_before_if) ||
85 !nir_block_dominates(def->parent_instr->block, block_before_if)) {
86 is_valid = false;
87 break;
88 }
89 }
90
91 if (is_valid)
92 return true;
93
94 struct nir_phi_builder *pb = prep_build_phi(state);
95
96 BITSET_SET(state->def_set, def->parent_instr->block->index);
97
98 struct nir_phi_builder_value *val =
99 nir_phi_builder_add_value(pb, def->num_components, def->bit_size,
100 state->def_set);
101
102 nir_phi_builder_value_set_block_def(val, def->parent_instr->block, def);
103
104 nir_foreach_use_safe(src, def) {
105 nir_block *src_block = get_src_block(src);
106 if (src_block == def->parent_instr->block) {
107 assert(nir_phi_builder_value_get_block_def(val, src_block) == def);
108 continue;
109 }
110
111 nir_ssa_def *block_def =
112 nir_phi_builder_value_get_block_def(val, src_block);
113 if (block_def == def)
114 continue;
115
116 /* If def was a deref and the use we're looking at is a deref that
117 * isn't a cast, we need to wrap it in a cast so we don't loose any
118 * deref information.
119 */
120 if (def->parent_instr->type == nir_instr_type_deref &&
121 src->parent_instr->type == nir_instr_type_deref &&
122 nir_instr_as_deref(src->parent_instr)->deref_type != nir_deref_type_cast) {
123 nir_deref_instr *cast =
124 nir_deref_instr_create(state->impl->function->shader,
125 nir_deref_type_cast);
126
127 nir_deref_instr *deref = nir_instr_as_deref(def->parent_instr);
128 cast->mode = deref->mode;
129 cast->type = deref->type;
130 cast->parent = nir_src_for_ssa(block_def);
131 cast->cast.ptr_stride = nir_deref_instr_array_stride(deref);
132
133 nir_ssa_dest_init(&cast->instr, &cast->dest,
134 def->num_components, def->bit_size, NULL);
135 nir_instr_insert(nir_before_instr(src->parent_instr),
136 &cast->instr);
137 block_def = &cast->dest.ssa;
138 }
139
140 nir_instr_rewrite_src(src->parent_instr, src, nir_src_for_ssa(block_def));
141 }
142
143 nir_foreach_if_use_safe(src, def) {
144 nir_block *block_before_if =
145 nir_cf_node_as_block(nir_cf_node_prev(&src->parent_if->cf_node));
146 if (block_before_if == def->parent_instr->block) {
147 assert(nir_phi_builder_value_get_block_def(val, block_before_if) == def);
148 continue;
149 }
150
151 nir_ssa_def *block_def =
152 nir_phi_builder_value_get_block_def(val, block_before_if);
153 if (block_def == def)
154 continue;
155
156 nir_if_rewrite_condition(src->parent_if, nir_src_for_ssa(block_def));
157 }
158
159 return true;
160 }
161
162 bool
163 nir_repair_ssa_impl(nir_function_impl *impl)
164 {
165 struct repair_ssa_state state;
166
167 state.impl = impl;
168 state.phi_builder = NULL;
169 state.progress = false;
170
171 nir_metadata_require(impl, nir_metadata_block_index |
172 nir_metadata_dominance);
173
174 nir_foreach_block(block, impl) {
175 nir_foreach_instr_safe(instr, block) {
176 nir_foreach_ssa_def(instr, repair_ssa_def, &state);
177 }
178 }
179
180 if (state.progress)
181 nir_metadata_preserve(impl, nir_metadata_block_index |
182 nir_metadata_dominance);
183
184 if (state.phi_builder) {
185 nir_phi_builder_finish(state.phi_builder);
186 ralloc_free(state.def_set);
187 }
188
189 return state.progress;
190 }
191
192 /** This pass can be used to repair SSA form in a shader.
193 *
194 * Sometimes a transformation (such as return lowering) will have to make
195 * changes to a shader which, while still correct, break some of NIR's SSA
196 * invariants. This pass will insert ssa_undefs and phi nodes as needed to
197 * get the shader back into SSA that the validator will like.
198 */
199 bool
200 nir_repair_ssa(nir_shader *shader)
201 {
202 bool progress = false;
203
204 nir_foreach_function(function, shader) {
205 if (function->impl)
206 progress = nir_repair_ssa_impl(function->impl) || progress;
207 }
208
209 return progress;
210 }