Line data Source code
1 : /* Scheduler hooks for IA-32 which implement Core 2 specific logic.
2 : Copyright (C) 1988-2026 Free Software Foundation, Inc.
3 :
4 : This file is part of GCC.
5 :
6 : GCC is free software; you can redistribute it and/or modify
7 : it under the terms of the GNU General Public License as published by
8 : the Free Software Foundation; either version 3, or (at your option)
9 : any later version.
10 :
11 : GCC is distributed in the hope that it will be useful,
12 : but WITHOUT ANY WARRANTY; without even the implied warranty of
13 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 : GNU General Public License for more details.
15 :
16 : You should have received a copy of the GNU General Public License
17 : along with GCC; see the file COPYING3. If not see
18 : <http://www.gnu.org/licenses/>. */
19 :
20 : #define IN_TARGET_CODE 1
21 :
22 : #include "config.h"
23 : #include "system.h"
24 : #include "coretypes.h"
25 : #include "backend.h"
26 : #include "rtl.h"
27 : #include "tree.h"
28 : #include "cfghooks.h"
29 : #include "tm_p.h"
30 : #include "insn-config.h"
31 : #include "insn-attr.h"
32 : #include "recog.h"
33 : #include "target.h"
34 : #include "rtl-iter.h"
35 : #include "regset.h"
36 : #include "sched-int.h"
37 :
38 :
39 : /* Model decoder of Core 2/i7.
40 : Below hooks for multipass scheduling (see haifa-sched.cc:max_issue)
41 : track the instruction fetch block boundaries and make sure that long
42 : (9+ bytes) instructions are assigned to D0. */
43 :
44 : /* Maximum length of an insn that can be handled by
45 : a secondary decoder unit. '8' for Core 2/i7. */
46 : static int core2i7_secondary_decoder_max_insn_size;
47 :
48 : /* Ifetch block size, i.e., number of bytes decoder reads per cycle.
49 : '16' for Core 2/i7. */
50 : static int core2i7_ifetch_block_size;
51 :
52 : /* Maximum number of instructions decoder can handle per cycle.
53 : '6' for Core 2/i7. */
54 : static int core2i7_ifetch_block_max_insns;
55 :
56 : typedef struct ix86_first_cycle_multipass_data_ *
57 : ix86_first_cycle_multipass_data_t;
58 : typedef const struct ix86_first_cycle_multipass_data_ *
59 : const_ix86_first_cycle_multipass_data_t;
60 :
61 : /* A variable to store target state across calls to max_issue within
62 : one cycle. */
63 : static struct ix86_first_cycle_multipass_data_ _ix86_first_cycle_multipass_data,
64 : *ix86_first_cycle_multipass_data = &_ix86_first_cycle_multipass_data;
65 :
66 : /* Initialize DATA. */
67 : static void
68 118648174 : core2i7_first_cycle_multipass_init (void *_data)
69 : {
70 118648174 : ix86_first_cycle_multipass_data_t data
71 : = (ix86_first_cycle_multipass_data_t) _data;
72 :
73 118648174 : data->ifetch_block_len = 0;
74 118648174 : data->ifetch_block_n_insns = 0;
75 118648174 : data->ready_try_change = NULL;
76 118648174 : data->ready_try_change_size = 0;
77 118648174 : }
78 :
79 : /* Advancing the cycle; reset ifetch block counts. */
80 : static void
81 45774424 : core2i7_dfa_post_advance_cycle (void)
82 : {
83 45774424 : ix86_first_cycle_multipass_data_t data = ix86_first_cycle_multipass_data;
84 :
85 45774424 : gcc_assert (data->ifetch_block_n_insns <= core2i7_ifetch_block_max_insns);
86 :
87 45774424 : data->ifetch_block_len = 0;
88 45774424 : data->ifetch_block_n_insns = 0;
89 45774424 : }
90 :
91 : /* Filter out insns from ready_try that the core will not be able to issue
92 : on current cycle due to decoder. */
93 : static void
94 165835967 : core2i7_first_cycle_multipass_filter_ready_try
95 : (const_ix86_first_cycle_multipass_data_t data,
96 : signed char *ready_try, int n_ready, bool first_cycle_insn_p)
97 : {
98 642455097 : while (n_ready--)
99 : {
100 476619130 : rtx_insn *insn;
101 476619130 : int insn_size;
102 :
103 476619130 : if (ready_try[n_ready])
104 208699780 : continue;
105 :
106 267919350 : insn = get_ready_element (n_ready);
107 267919350 : insn_size = ix86_min_insn_size (insn);
108 :
109 267919350 : if (/* If this is a too long an insn for a secondary decoder ... */
110 : (!first_cycle_insn_p
111 211269552 : && insn_size > core2i7_secondary_decoder_max_insn_size)
112 : /* ... or it would not fit into the ifetch block ... */
113 242908019 : || data->ifetch_block_len + insn_size > core2i7_ifetch_block_size
114 : /* ... or the decoder is full already ... */
115 165438402 : || data->ifetch_block_n_insns + 1 > core2i7_ifetch_block_max_insns)
116 : /* ... mask the insn out. */
117 : {
118 102481020 : ready_try[n_ready] = 1;
119 :
120 102481020 : if (data->ready_try_change)
121 94907696 : bitmap_set_bit (data->ready_try_change, n_ready);
122 : }
123 : }
124 165835967 : }
125 :
126 : /* Prepare for a new round of multipass lookahead scheduling. */
127 : static void
128 54903641 : core2i7_first_cycle_multipass_begin (void *_data,
129 : signed char *ready_try, int n_ready,
130 : bool first_cycle_insn_p)
131 : {
132 54903641 : ix86_first_cycle_multipass_data_t data
133 : = (ix86_first_cycle_multipass_data_t) _data;
134 54903641 : const_ix86_first_cycle_multipass_data_t prev_data
135 : = ix86_first_cycle_multipass_data;
136 :
137 : /* Restore the state from the end of the previous round. */
138 54903641 : data->ifetch_block_len = prev_data->ifetch_block_len;
139 54903641 : data->ifetch_block_n_insns = prev_data->ifetch_block_n_insns;
140 :
141 : /* Filter instructions that cannot be issued on current cycle due to
142 : decoder restrictions. */
143 54903641 : core2i7_first_cycle_multipass_filter_ready_try (data, ready_try, n_ready,
144 : first_cycle_insn_p);
145 54903641 : }
146 :
147 : /* INSN is being issued in current solution. Account for its impact on
148 : the decoder model. */
149 : static void
150 110932326 : core2i7_first_cycle_multipass_issue (void *_data,
151 : signed char *ready_try, int n_ready,
152 : rtx_insn *insn, const void *_prev_data)
153 : {
154 110932326 : ix86_first_cycle_multipass_data_t data
155 : = (ix86_first_cycle_multipass_data_t) _data;
156 110932326 : const_ix86_first_cycle_multipass_data_t prev_data
157 : = (const_ix86_first_cycle_multipass_data_t) _prev_data;
158 :
159 110932326 : int insn_size = ix86_min_insn_size (insn);
160 :
161 110932326 : data->ifetch_block_len = prev_data->ifetch_block_len + insn_size;
162 110932326 : data->ifetch_block_n_insns = prev_data->ifetch_block_n_insns + 1;
163 110932326 : gcc_assert (data->ifetch_block_len <= core2i7_ifetch_block_size
164 : && data->ifetch_block_n_insns <= core2i7_ifetch_block_max_insns);
165 :
166 : /* Allocate or resize the bitmap for storing INSN's effect on ready_try. */
167 110932326 : if (!data->ready_try_change)
168 : {
169 16138300 : data->ready_try_change = sbitmap_alloc (n_ready);
170 16138300 : data->ready_try_change_size = n_ready;
171 : }
172 94794026 : else if (data->ready_try_change_size < n_ready)
173 : {
174 1060528 : data->ready_try_change = sbitmap_resize (data->ready_try_change,
175 : n_ready, 0);
176 1060528 : data->ready_try_change_size = n_ready;
177 : }
178 110932326 : bitmap_clear (data->ready_try_change);
179 :
180 : /* Filter out insns from ready_try that the core will not be able to issue
181 : on current cycle due to decoder. */
182 110932326 : core2i7_first_cycle_multipass_filter_ready_try (data, ready_try, n_ready,
183 : false);
184 110932326 : }
185 :
186 : /* Revert the effect on ready_try. */
187 : static void
188 56223098 : core2i7_first_cycle_multipass_backtrack (const void *_data,
189 : signed char *ready_try,
190 : int n_ready ATTRIBUTE_UNUSED)
191 : {
192 56223098 : const_ix86_first_cycle_multipass_data_t data
193 : = (const_ix86_first_cycle_multipass_data_t) _data;
194 56223098 : unsigned int i = 0;
195 56223098 : sbitmap_iterator sbi;
196 :
197 56223098 : gcc_assert (bitmap_last_set_bit (data->ready_try_change) < n_ready);
198 205903267 : EXECUTE_IF_SET_IN_BITMAP (data->ready_try_change, 0, i, sbi)
199 : {
200 93457071 : ready_try[i] = 0;
201 : }
202 56223098 : }
203 :
204 : /* Save the result of multipass lookahead scheduling for the next round. */
205 : static void
206 54903641 : core2i7_first_cycle_multipass_end (const void *_data)
207 : {
208 54903641 : const_ix86_first_cycle_multipass_data_t data
209 : = (const_ix86_first_cycle_multipass_data_t) _data;
210 54903641 : ix86_first_cycle_multipass_data_t next_data
211 : = ix86_first_cycle_multipass_data;
212 :
213 54903641 : if (data != NULL)
214 : {
215 52741298 : next_data->ifetch_block_len = data->ifetch_block_len;
216 52741298 : next_data->ifetch_block_n_insns = data->ifetch_block_n_insns;
217 : }
218 54903641 : }
219 :
220 : /* Deallocate target data. */
221 : static void
222 118648174 : core2i7_first_cycle_multipass_fini (void *_data)
223 : {
224 118648174 : ix86_first_cycle_multipass_data_t data
225 : = (ix86_first_cycle_multipass_data_t) _data;
226 :
227 118648174 : if (data->ready_try_change)
228 : {
229 16138300 : sbitmap_free (data->ready_try_change);
230 16138300 : data->ready_try_change = NULL;
231 16138300 : data->ready_try_change_size = 0;
232 : }
233 118648174 : }
234 :
235 : void
236 917458 : ix86_core2i7_init_hooks (void)
237 : {
238 917458 : targetm.sched.dfa_post_advance_cycle
239 917458 : = core2i7_dfa_post_advance_cycle;
240 917458 : targetm.sched.first_cycle_multipass_init
241 917458 : = core2i7_first_cycle_multipass_init;
242 917458 : targetm.sched.first_cycle_multipass_begin
243 917458 : = core2i7_first_cycle_multipass_begin;
244 917458 : targetm.sched.first_cycle_multipass_issue
245 917458 : = core2i7_first_cycle_multipass_issue;
246 917458 : targetm.sched.first_cycle_multipass_backtrack
247 917458 : = core2i7_first_cycle_multipass_backtrack;
248 917458 : targetm.sched.first_cycle_multipass_end
249 917458 : = core2i7_first_cycle_multipass_end;
250 917458 : targetm.sched.first_cycle_multipass_fini
251 917458 : = core2i7_first_cycle_multipass_fini;
252 :
253 : /* Set decoder parameters. */
254 917458 : core2i7_secondary_decoder_max_insn_size = 8;
255 917458 : core2i7_ifetch_block_size = 16;
256 917458 : core2i7_ifetch_block_max_insns = 6;
257 917458 : }
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