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25 * @file v3d_vir_lower_uniforms.c
27 * This is the pre-code-generation pass for fixing up instructions that try to
28 * read from multiple uniform values.
31 #include "v3d_compiler.h"
32 #include "util/hash_table.h"
33 #include "util/u_math.h"
35 static inline uint32_t
36 index_hash(const void *key
)
38 return (uintptr_t)key
;
42 index_compare(const void *a
, const void *b
)
48 add_uniform(struct hash_table
*ht
, struct qreg reg
)
50 struct hash_entry
*entry
;
51 void *key
= (void *)(uintptr_t)(reg
.index
+ 1);
53 entry
= _mesa_hash_table_search(ht
, key
);
57 _mesa_hash_table_insert(ht
, key
, (void *)(uintptr_t)1);
62 remove_uniform(struct hash_table
*ht
, struct qreg reg
)
64 struct hash_entry
*entry
;
65 void *key
= (void *)(uintptr_t)(reg
.index
+ 1);
67 entry
= _mesa_hash_table_search(ht
, key
);
69 entry
->data
= (void *)(((uintptr_t) entry
->data
) - 1);
70 if (entry
->data
== NULL
)
71 _mesa_hash_table_remove(ht
, entry
);
75 is_lowerable_uniform(struct qinst
*inst
, int i
)
77 if (inst
->src
[i
].file
!= QFILE_UNIF
)
79 return i
!= vir_get_implicit_uniform_src(inst
);
82 /* Returns the number of different uniform values referenced by the
86 vir_get_instruction_uniform_count(struct qinst
*inst
)
90 for (int i
= 0; i
< vir_get_nsrc(inst
); i
++) {
91 if (inst
->src
[i
].file
!= QFILE_UNIF
)
94 bool is_duplicate
= false;
95 for (int j
= 0; j
< i
; j
++) {
96 if (inst
->src
[j
].file
== QFILE_UNIF
&&
97 inst
->src
[j
].index
== inst
->src
[i
].index
) {
110 vir_lower_uniforms(struct v3d_compile
*c
)
112 struct hash_table
*ht
=
113 _mesa_hash_table_create(c
, index_hash
, index_compare
);
115 /* Walk the instruction list, finding which instructions have more
116 * than one uniform referenced, and add those uniform values to the
119 vir_for_each_inst_inorder(inst
, c
) {
120 uint32_t nsrc
= vir_get_nsrc(inst
);
122 if (vir_get_instruction_uniform_count(inst
) <= 1)
125 for (int i
= 0; i
< nsrc
; i
++) {
126 if (is_lowerable_uniform(inst
, i
))
127 add_uniform(ht
, inst
->src
[i
]);
131 while (ht
->entries
) {
132 /* Find the most commonly used uniform in instructions that
133 * need a uniform lowered.
135 uint32_t max_count
= 0;
136 uint32_t max_index
= 0;
137 hash_table_foreach(ht
, entry
) {
138 uint32_t count
= (uintptr_t)entry
->data
;
139 uint32_t index
= (uintptr_t)entry
->key
- 1;
140 if (count
> max_count
) {
146 struct qreg unif
= vir_reg(QFILE_UNIF
, max_index
);
148 /* Now, find the instructions using this uniform and make them
149 * reference a temp instead.
151 vir_for_each_block(block
, c
) {
152 struct qreg temp
= c
->undef
;
154 vir_for_each_inst(inst
, block
) {
155 uint32_t nsrc
= vir_get_nsrc(inst
);
157 uint32_t count
= vir_get_instruction_uniform_count(inst
);
162 bool removed
= false;
163 for (int i
= 0; i
< nsrc
; i
++) {
164 if (is_lowerable_uniform(inst
, i
) &&
165 inst
->src
[i
].index
== max_index
) {
166 /* If the block doesn't have a
167 * load of the uniform yet,
168 * add it now. We could
169 * potentially do better and
170 * CSE MOVs from multiple
171 * blocks into dominating
172 * blocks, except that may
173 * cause troubles for register
176 if (temp
.file
== QFILE_NULL
) {
178 vir_before_inst(inst
);
179 temp
= vir_MOV(c
, unif
);
183 remove_uniform(ht
, unif
);
190 /* If the instruction doesn't need lowering any more,
191 * then drop it from the list.
194 for (int i
= 0; i
< nsrc
; i
++) {
195 if (is_lowerable_uniform(inst
, i
))
196 remove_uniform(ht
, inst
->src
[i
]);
203 _mesa_hash_table_destroy(ht
, NULL
);