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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
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
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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");
46 qir_remove_instruction(inst
);
50 qir_opt_dead_code(struct vc4_compile
*c
)
52 bool progress
= false;
53 bool *used
= calloc(c
->num_temps
, sizeof(bool));
55 /* Whether we're eliminating texture setup currently. */
58 struct simple_node
*node
, *t
;
59 for (node
= c
->instructions
.prev
, t
= node
->prev
;
60 &c
->instructions
!= node
;
61 node
= t
, t
= t
->prev
) {
62 struct qinst
*inst
= (struct qinst
*)node
;
64 if (inst
->dst
.file
== QFILE_TEMP
&&
65 !used
[inst
->dst
.index
] &&
66 (!qir_has_side_effects(inst
) ||
67 inst
->op
== QOP_TEX_RESULT
)) {
68 if (inst
->op
== QOP_TEX_RESULT
) {
70 c
->num_texture_samples
--;
78 if (qir_depends_on_flags(inst
))
80 if (inst
->op
== QOP_SF
) {
89 if (inst
->op
== QOP_TEX_RESULT
)
92 if (dce_tex
&& (inst
->op
== QOP_TEX_S
||
93 inst
->op
== QOP_TEX_T
||
94 inst
->op
== QOP_TEX_R
||
95 inst
->op
== QOP_TEX_B
)) {
101 for (int i
= 0; i
< qir_get_op_nsrc(inst
->op
); i
++) {
102 if (inst
->src
[i
].file
== QFILE_TEMP
)
103 used
[inst
->src
[i
].index
] = true;