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25 /** @file brw_vec4_cmod_propagation.cpp
27 * Really similar to brw_fs_cmod_propagation but adapted to vec4 needs. Check
28 * brw_fs_cmod_propagation for further details on the rationale behind this
39 opt_cmod_propagation_local(bblock_t
*block
)
41 bool progress
= false;
42 int ip
= block
->end_ip
+ 1;
44 foreach_inst_in_block_reverse_safe(vec4_instruction
, inst
, block
) {
47 if ((inst
->opcode
!= BRW_OPCODE_AND
&&
48 inst
->opcode
!= BRW_OPCODE_CMP
&&
49 inst
->opcode
!= BRW_OPCODE_MOV
) ||
50 inst
->predicate
!= BRW_PREDICATE_NONE
||
51 !inst
->dst
.is_null() ||
52 inst
->src
[0].file
!= VGRF
||
56 if (inst
->opcode
== BRW_OPCODE_AND
&&
57 !(inst
->src
[1].is_one() &&
58 inst
->conditional_mod
== BRW_CONDITIONAL_NZ
&&
59 !inst
->src
[0].negate
))
62 if (inst
->opcode
== BRW_OPCODE_CMP
&& !inst
->src
[1].is_zero())
65 if (inst
->opcode
== BRW_OPCODE_MOV
&&
66 inst
->conditional_mod
!= BRW_CONDITIONAL_NZ
)
69 bool read_flag
= false;
70 foreach_inst_in_block_reverse_starting_from(vec4_instruction
, scan_inst
, inst
) {
71 if (inst
->src
[0].in_range(scan_inst
->dst
,
72 scan_inst
->regs_written
)) {
73 if ((scan_inst
->predicate
&& scan_inst
->opcode
!= BRW_OPCODE_SEL
) ||
74 scan_inst
->dst
.reg_offset
!= inst
->src
[0].reg_offset
||
75 (scan_inst
->dst
.writemask
!= WRITEMASK_X
&&
76 scan_inst
->dst
.writemask
!= WRITEMASK_XYZW
) ||
77 (scan_inst
->dst
.writemask
== WRITEMASK_XYZW
&&
78 inst
->src
[0].swizzle
!= BRW_SWIZZLE_XYZW
) ||
79 (inst
->dst
.writemask
& ~scan_inst
->dst
.writemask
) != 0) {
83 /* CMP's result is the same regardless of dest type. */
84 if (inst
->conditional_mod
== BRW_CONDITIONAL_NZ
&&
85 scan_inst
->opcode
== BRW_OPCODE_CMP
&&
86 (inst
->dst
.type
== BRW_REGISTER_TYPE_D
||
87 inst
->dst
.type
== BRW_REGISTER_TYPE_UD
)) {
93 /* If the AND wasn't handled by the previous case, it isn't safe
96 if (inst
->opcode
== BRW_OPCODE_AND
)
99 /* Comparisons operate differently for ints and floats */
100 if (scan_inst
->dst
.type
!= inst
->dst
.type
&&
101 (scan_inst
->dst
.type
== BRW_REGISTER_TYPE_F
||
102 inst
->dst
.type
== BRW_REGISTER_TYPE_F
))
105 /* If the instruction generating inst's source also wrote the
106 * flag, and inst is doing a simple .nz comparison, then inst
107 * is redundant - the appropriate value is already in the flag
108 * register. Delete inst.
110 if (inst
->conditional_mod
== BRW_CONDITIONAL_NZ
&&
111 !inst
->src
[0].negate
&&
112 scan_inst
->writes_flag()) {
118 /* Otherwise, try propagating the conditional. */
119 enum brw_conditional_mod cond
=
120 inst
->src
[0].negate
? brw_swap_cmod(inst
->conditional_mod
)
121 : inst
->conditional_mod
;
123 if (scan_inst
->can_do_cmod() &&
124 ((!read_flag
&& scan_inst
->conditional_mod
== BRW_CONDITIONAL_NONE
) ||
125 scan_inst
->conditional_mod
== cond
)) {
126 scan_inst
->conditional_mod
= cond
;
133 if (scan_inst
->writes_flag())
136 read_flag
= read_flag
|| scan_inst
->reads_flag();
144 vec4_visitor::opt_cmod_propagation()
146 bool progress
= false;
148 foreach_block_reverse(block
, cfg
) {
149 progress
= opt_cmod_propagation_local(block
) || progress
;
153 invalidate_live_intervals();
158 } /* namespace brw */