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5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
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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,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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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
25 * @file vc4_opt_dead_code.c
27 * This is a simmple dead code eliminator for QIR with no control flow.
29 * It walks from the bottom of the instruction list, removing instructions
30 * with a destination that is never used, and marking the sources of non-dead
31 * instructions as used.
39 dce(struct vc4_compile
*c
, struct qinst
*inst
)
42 fprintf(stderr
, "Removing: ");
43 qir_dump_inst(c
, inst
);
44 fprintf(stderr
, "\n");
47 qir_remove_instruction(c
, inst
);
51 has_nonremovable_reads(struct vc4_compile
*c
, struct qinst
*inst
)
53 for (int i
= 0; i
< qir_get_op_nsrc(inst
->op
); i
++) {
54 if (inst
->src
[i
].file
== QFILE_VPM
) {
55 uint32_t attr
= inst
->src
[i
].index
/ 4;
56 uint32_t offset
= (inst
->src
[i
].index
% 4) * 4;
58 if (c
->vattr_sizes
[attr
] != offset
+ 4)
61 /* Can't get rid of the last VPM read, or the
62 * simulator (at least) throws an error.
64 uint32_t total_size
= 0;
65 for (uint32_t i
= 0; i
< ARRAY_SIZE(c
->vattr_sizes
); i
++)
66 total_size
+= c
->vattr_sizes
[i
];
71 if (inst
->src
[i
].file
== QFILE_VARY
&&
72 c
->input_slots
[inst
->src
[i
].index
].slot
== 0xff) {
81 qir_opt_dead_code(struct vc4_compile
*c
)
83 bool progress
= false;
84 bool *used
= calloc(c
->num_temps
, sizeof(bool));
86 /* Whether we're eliminating texture setup currently. */
89 struct list_head
*node
, *t
;
90 for (node
= c
->instructions
.prev
, t
= node
->prev
;
91 &c
->instructions
!= node
;
92 node
= t
, t
= t
->prev
) {
93 struct qinst
*inst
= (struct qinst
*)node
;
95 if (inst
->dst
.file
== QFILE_TEMP
&&
96 !used
[inst
->dst
.index
] &&
98 (!qir_has_side_effects(c
, inst
) ||
99 inst
->op
== QOP_TEX_RESULT
) &&
100 !has_nonremovable_reads(c
, inst
)) {
101 if (inst
->op
== QOP_TEX_RESULT
) {
103 c
->num_texture_samples
--;
106 for (int i
= 0; i
< qir_get_op_nsrc(inst
->op
); i
++) {
107 if (inst
->src
[i
].file
!= QFILE_VPM
)
109 uint32_t attr
= inst
->src
[i
].index
/ 4;
110 uint32_t offset
= (inst
->src
[i
].index
% 4) * 4;
112 if (c
->vattr_sizes
[attr
] == offset
+ 4) {
114 c
->vattr_sizes
[attr
] -= 4;
123 if (qir_depends_on_flags(inst
))
128 fprintf(stderr
, "Removing SF on: ");
129 qir_dump_inst(c
, inst
);
130 fprintf(stderr
, "\n");
139 if (inst
->op
== QOP_TEX_RESULT
)
142 if (dce_tex
&& (inst
->op
== QOP_TEX_S
||
143 inst
->op
== QOP_TEX_T
||
144 inst
->op
== QOP_TEX_R
||
145 inst
->op
== QOP_TEX_B
||
146 inst
->op
== QOP_TEX_DIRECT
)) {
152 for (int i
= 0; i
< qir_get_op_nsrc(inst
->op
); i
++) {
153 if (inst
->src
[i
].file
== QFILE_TEMP
)
154 used
[inst
->src
[i
].index
] = true;