2 * Copyright © 2016 Intel Corporation
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9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
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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,
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20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
25 #include "nir_phi_builder.h"
27 struct repair_ssa_state
{
28 nir_function_impl
*impl
;
31 struct nir_phi_builder
*phi_builder
;
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
)
40 const unsigned num_words
= BITSET_WORDS(state
->impl
->num_blocks
);
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
);
48 /* We're going to build a phi. That's progress. */
49 state
->progress
= true;
51 /* Set the defs set to empty */
52 memset(state
->def_set
, 0, num_words
* sizeof(*state
->def_set
));
54 return state
->phi_builder
;
58 get_src_block(nir_src
*src
)
60 if (src
->parent_instr
->type
== nir_instr_type_phi
) {
61 return exec_node_data(nir_phi_src
, src
, src
)->pred
;
63 return src
->parent_instr
->block
;
68 repair_ssa_def(nir_ssa_def
*def
, void *void_state
)
70 struct repair_ssa_state
*state
= void_state
;
73 nir_foreach_use(src
, def
) {
74 if (!nir_block_dominates(def
->parent_instr
->block
, get_src_block(src
))) {
80 nir_foreach_if_use(src
, def
) {
81 nir_block
*block_before_if
=
82 nir_cf_node_as_block(nir_cf_node_prev(&src
->parent_if
->cf_node
));
83 if (!nir_block_dominates(def
->parent_instr
->block
, block_before_if
)) {
92 struct nir_phi_builder
*pb
= prep_build_phi(state
);
94 BITSET_SET(state
->def_set
, def
->parent_instr
->block
->index
);
96 struct nir_phi_builder_value
*val
=
97 nir_phi_builder_add_value(pb
, def
->num_components
, def
->bit_size
,
100 nir_phi_builder_value_set_block_def(val
, def
->parent_instr
->block
, def
);
102 nir_foreach_use_safe(src
, def
) {
103 nir_block
*src_block
= get_src_block(src
);
104 if (!nir_block_dominates(def
->parent_instr
->block
, src_block
)) {
105 nir_instr_rewrite_src(src
->parent_instr
, src
, nir_src_for_ssa(
106 nir_phi_builder_value_get_block_def(val
, src_block
)));
110 nir_foreach_if_use_safe(src
, def
) {
111 nir_block
*block_before_if
=
112 nir_cf_node_as_block(nir_cf_node_prev(&src
->parent_if
->cf_node
));
113 if (!nir_block_dominates(def
->parent_instr
->block
, block_before_if
)) {
114 nir_if_rewrite_condition(src
->parent_if
, nir_src_for_ssa(
115 nir_phi_builder_value_get_block_def(val
, block_before_if
)));
123 nir_repair_ssa_impl(nir_function_impl
*impl
)
125 struct repair_ssa_state state
;
128 state
.phi_builder
= NULL
;
129 state
.progress
= false;
131 nir_metadata_require(impl
, nir_metadata_block_index
|
132 nir_metadata_dominance
);
134 nir_foreach_block(block
, impl
) {
135 nir_foreach_instr_safe(instr
, block
) {
136 nir_foreach_ssa_def(instr
, repair_ssa_def
, &state
);
141 nir_metadata_preserve(impl
, nir_metadata_block_index
|
142 nir_metadata_dominance
);
144 if (state
.phi_builder
) {
145 nir_phi_builder_finish(state
.phi_builder
);
146 ralloc_free(state
.def_set
);
149 return state
.progress
;
152 /** This pass can be used to repair SSA form in a shader.
154 * Sometimes a transformation (such as return lowering) will have to make
155 * changes to a shader which, while still correct, break some of NIR's SSA
156 * invariants. This pass will insert ssa_undefs and phi nodes as needed to
157 * get the shader back into SSA that the validator will like.
160 nir_repair_ssa(nir_shader
*shader
)
162 bool progress
= false;
164 nir_foreach_function(function
, shader
) {
166 progress
= nir_repair_ssa_impl(function
->impl
) || progress
;