f20768e12e4cbd0bb66b78e2977823a972de4306
2 * Copyright (c) 2017 Lima Project
4 * Permission is hereby granted, free of charge, to any person obtaining a
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, sub license,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the
12 * next paragraph) shall be included in all copies or substantial portions
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 NON-INFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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
21 * DEALINGS IN THE SOFTWARE.
29 /* Register sensitive schedule algorithm from paper:
30 * "Register-Sensitive Selection, Duplication, and Sequencing of Instructions"
31 * Author: Vivek Sarkar, Mauricio J. Serrano, Barbara B. Simons
34 static void schedule_calc_sched_info(gpir_node
*node
)
37 float extra_reg
= 1.0f
;
39 /* update all children's sched info */
40 gpir_node_foreach_pred(node
, dep
) {
41 gpir_node
*pred
= dep
->pred
;
43 if (pred
->rsched
.reg_pressure
< 0)
44 schedule_calc_sched_info(pred
);
46 int est
= pred
->rsched
.est
+ 1;
47 if (node
->rsched
.est
< est
)
48 node
->rsched
.est
= est
;
50 float reg_weight
= 1.0f
- 1.0f
/ list_length(&pred
->succ_list
);
51 if (extra_reg
> reg_weight
)
52 extra_reg
= reg_weight
;
59 node
->rsched
.reg_pressure
= 0;
65 gpir_node_foreach_pred(node
, dep
) {
66 gpir_node
*pred
= dep
->pred
;
67 reg
[i
++] = pred
->rsched
.reg_pressure
;
71 for (i
= 0; i
< n
- 1; i
++) {
72 for (int j
= 0; j
< n
- i
- 1; j
++) {
73 if (reg
[j
] > reg
[j
+ 1]) {
74 float tmp
= reg
[j
+ 1];
81 for (i
= 0; i
< n
; i
++) {
82 float pressure
= reg
[i
] + n
- (i
+ 1);
83 if (pressure
> node
->rsched
.reg_pressure
)
84 node
->rsched
.reg_pressure
= pressure
;
87 /* If all children of this node have multi parents, then this
88 * node need an extra reg to store its result. For example,
89 * it's not fair for parent has the same reg pressure as child
90 * if n==1 and child's successor>1, because we need 2 reg for
93 * But we can't add a full reg to the reg_pressure, because the
94 * last parent of a multi-successor child doesn't need an extra
95 * reg. For example, a single child (with multi successor) node
96 * should has less reg pressure than a two children (with single
99 * extra reg = min(all child)(1.0 - 1.0 / num successor)
101 node
->rsched
.reg_pressure
+= extra_reg
;
104 static void schedule_insert_ready_list(struct list_head
*ready_list
,
105 gpir_node
*insert_node
)
107 struct list_head
*insert_pos
= ready_list
;
109 list_for_each_entry(gpir_node
, node
, ready_list
, list
) {
110 if (insert_node
->rsched
.parent_index
< node
->rsched
.parent_index
||
111 (insert_node
->rsched
.parent_index
== node
->rsched
.parent_index
&&
112 (insert_node
->rsched
.reg_pressure
< node
->rsched
.reg_pressure
||
113 (insert_node
->rsched
.reg_pressure
== node
->rsched
.reg_pressure
&&
114 (insert_node
->rsched
.est
>= node
->rsched
.est
))))) {
115 insert_pos
= &node
->list
;
120 list_del(&insert_node
->list
);
121 list_addtail(&insert_node
->list
, insert_pos
);
124 static void schedule_ready_list(gpir_block
*block
, struct list_head
*ready_list
)
126 if (list_empty(ready_list
))
129 gpir_node
*node
= list_first_entry(ready_list
, gpir_node
, list
);
130 list_del(&node
->list
);
132 /* schedule the node to the block node list */
133 list_add(&node
->list
, &block
->node_list
);
134 node
->rsched
.scheduled
= true;
135 block
->rsched
.node_index
--;
137 gpir_node_foreach_pred(node
, dep
) {
138 gpir_node
*pred
= dep
->pred
;
139 pred
->rsched
.parent_index
= block
->rsched
.node_index
;
142 gpir_node_foreach_succ(pred
, dep
) {
143 gpir_node
*succ
= dep
->succ
;
144 if (!succ
->rsched
.scheduled
) {
149 /* all successor have been scheduled */
151 schedule_insert_ready_list(ready_list
, pred
);
154 schedule_ready_list(block
, ready_list
);
157 static void schedule_block(gpir_block
*block
)
159 /* move all nodes to node_list, block->node_list will
160 * contain schedule result */
161 struct list_head node_list
;
162 list_replace(&block
->node_list
, &node_list
);
163 list_inithead(&block
->node_list
);
166 list_for_each_entry(gpir_node
, node
, &node_list
, list
) {
167 if (gpir_node_is_root(node
))
168 schedule_calc_sched_info(node
);
169 block
->rsched
.node_index
++;
173 struct list_head ready_list
;
174 list_inithead(&ready_list
);
177 list_for_each_entry_safe(gpir_node
, node
, &node_list
, list
) {
178 if (gpir_node_is_root(node
)) {
179 node
->rsched
.parent_index
= INT_MAX
;
180 schedule_insert_ready_list(&ready_list
, node
);
185 schedule_ready_list(block
, &ready_list
);
188 bool gpir_reduce_reg_pressure_schedule_prog(gpir_compiler
*comp
)
190 /* No need to build physical reg load/store dependency here,
191 * because we just exit SSA form, there should be at most
192 * one load and one store pair for a physical reg within a
193 * block, and the store must be after load with the output
194 * of load as input after some calculation. So we don't need to
195 * insert extra write-after-read or read-after-write dependecy
196 * for load/store nodes to maintain the right sequence before
199 * Also no need to handle SSA def/use in difference block,
200 * because we'll load/store SSA to a physical reg if def/use
201 * are not in the same block.
204 list_for_each_entry(gpir_block
, block
, &comp
->block_list
, list
) {
205 block
->rsched
.node_index
= 0;
206 list_for_each_entry_safe(gpir_node
, node
, &block
->node_list
, list
) {
207 node
->rsched
.reg_pressure
= -1;
208 node
->rsched
.est
= 0;
209 node
->rsched
.scheduled
= false;
213 list_for_each_entry(gpir_block
, block
, &comp
->block_list
, list
) {
214 schedule_block(block
);
217 gpir_debug("after reduce scheduler\n");
218 gpir_node_print_prog_seq(comp
);