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25 * @file vc4_opt_copy_propagation.c
27 * This implements simple copy propagation for QIR without control flow.
29 * For each temp, it keeps a qreg of which source it was MOVed from, if it
30 * was. If we see that used later, we can just reuse the source value, since
31 * we know we don't have control flow, and we have SSA for our values so
32 * there's no killing to worry about.
38 qir_opt_copy_propagation(struct vc4_compile
*c
)
40 bool progress
= false;
43 list_for_each_entry(struct qinst
, inst
, &c
->instructions
, link
) {
44 for (int i
= 0; i
< qir_get_op_nsrc(inst
->op
); i
++) {
45 int index
= inst
->src
[i
].index
;
46 if (inst
->src
[i
].file
== QFILE_TEMP
&&
48 qir_is_raw_mov(c
->defs
[index
]) &&
49 (c
->defs
[index
]->src
[0].file
== QFILE_TEMP
||
50 c
->defs
[index
]->src
[0].file
== QFILE_UNIF
)) {
52 fprintf(stderr
, "Copy propagate: ");
53 qir_dump_inst(c
, inst
);
54 fprintf(stderr
, "\n");
57 inst
->src
[i
] = c
->defs
[index
]->src
[0];
60 fprintf(stderr
, "to: ");
61 qir_dump_inst(c
, inst
);
62 fprintf(stderr
, "\n");