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25 #include "brw_fs_live_variables.h"
28 /** @file brw_fs_saturate_propagation.cpp
30 * Implements a pass that propagates the SAT modifier from a MOV.SAT into the
31 * instruction that produced the source of the MOV.SAT, thereby allowing the
32 * MOV's src and dst to be coalesced and the MOV removed.
39 * would be transformed into
41 * ADD.SAT tmp, src0, src1
46 opt_saturate_propagation_local(fs_visitor
*v
, bblock_t
*block
)
48 bool progress
= false;
49 int ip
= block
->end_ip
+ 1;
51 foreach_inst_in_block_reverse(fs_inst
, inst
, block
) {
54 if (inst
->opcode
!= BRW_OPCODE_MOV
||
55 inst
->dst
.file
!= GRF
||
56 inst
->src
[0].file
!= GRF
||
58 inst
->src
[0].negate
||
62 int src_var
= v
->live_intervals
->var_from_reg(inst
->src
[0]);
63 int src_end_ip
= v
->live_intervals
->end
[src_var
];
65 bool interfered
= false;
66 foreach_inst_in_block_reverse_starting_from(fs_inst
, scan_inst
, inst
, block
) {
67 if (scan_inst
->overwrites_reg(inst
->src
[0])) {
68 if (scan_inst
->is_partial_write())
71 if (scan_inst
->saturate
) {
72 inst
->saturate
= false;
74 } else if (src_end_ip
<= ip
|| inst
->dst
.equals(inst
->src
[0])) {
75 if (scan_inst
->can_do_saturate()) {
76 scan_inst
->saturate
= true;
77 inst
->saturate
= false;
83 for (int i
= 0; i
< scan_inst
->sources
; i
++) {
84 if (scan_inst
->src
[i
].file
== GRF
&&
85 scan_inst
->src
[i
].reg
== inst
->src
[0].reg
&&
86 scan_inst
->src
[i
].reg_offset
== inst
->src
[0].reg_offset
) {
87 if (scan_inst
->opcode
!= BRW_OPCODE_MOV
||
88 !scan_inst
->saturate
||
89 scan_inst
->src
[0].abs
||
90 scan_inst
->src
[0].negate
) {
106 fs_visitor::opt_saturate_propagation()
108 bool progress
= false;
110 calculate_live_intervals();
112 foreach_block (block
, cfg
) {
113 progress
= opt_saturate_propagation_local(this, block
) || progress
;
116 /* Live intervals are still valid. */