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0526a3ff | 1 | /* Loop optimizer initialization routines and RTL loop optimization passes. |
102973cc | 2 | Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc. |
6a606e3c | 3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
8 | Software Foundation; either version 2, or (at your option) any later | |
9 | version. | |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GCC; see the file COPYING. If not, write to the Free | |
67ce556b | 18 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
19 | 02110-1301, USA. */ | |
6a606e3c | 20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
24 | #include "tm.h" | |
25 | #include "rtl.h" | |
26 | #include "hard-reg-set.h" | |
42fe97ed | 27 | #include "obstack.h" |
6a606e3c | 28 | #include "basic-block.h" |
29 | #include "cfgloop.h" | |
30 | #include "cfglayout.h" | |
77fce4cd | 31 | #include "tree-pass.h" |
32 | #include "timevar.h" | |
33 | #include "flags.h" | |
6a606e3c | 34 | |
0526a3ff | 35 | \f |
36 | /* Initialize loop optimizer. This is used by the tree and RTL loop | |
c8d055f6 | 37 | optimizers. FLAGS specify what properties to compute and/or ensure for |
38 | loops. */ | |
6a606e3c | 39 | |
40 | struct loops * | |
3f5be5f4 | 41 | loop_optimizer_init (unsigned flags) |
6a606e3c | 42 | { |
4c36ffe6 | 43 | struct loops *loops = XCNEW (struct loops); |
6a606e3c | 44 | edge e; |
cd665a06 | 45 | edge_iterator ei; |
3a0ecac2 | 46 | static bool first_time = true; |
47 | ||
48 | if (first_time) | |
49 | { | |
50 | first_time = false; | |
51 | init_set_costs (); | |
52 | } | |
6a606e3c | 53 | |
54 | /* Avoid annoying special cases of edges going to exit | |
55 | block. */ | |
cd665a06 | 56 | |
57 | for (ei = ei_start (EXIT_BLOCK_PTR->preds); (e = ei_safe_edge (ei)); ) | |
ea091dfd | 58 | if ((e->flags & EDGE_FALLTHRU) && !single_succ_p (e->src)) |
6a606e3c | 59 | split_edge (e); |
cd665a06 | 60 | else |
61 | ei_next (&ei); | |
6a606e3c | 62 | |
63 | /* Find the loops. */ | |
64 | ||
ffc6b5d5 | 65 | if (flow_loops_find (loops) <= 1) |
6a606e3c | 66 | { |
67 | /* No loops. */ | |
68 | flow_loops_free (loops); | |
69 | free (loops); | |
0051c76a | 70 | |
6a606e3c | 71 | return NULL; |
72 | } | |
73 | ||
74 | /* Not going to update these. */ | |
75 | free (loops->cfg.rc_order); | |
76 | loops->cfg.rc_order = NULL; | |
77 | free (loops->cfg.dfs_order); | |
78 | loops->cfg.dfs_order = NULL; | |
79 | ||
6a606e3c | 80 | /* Create pre-headers. */ |
c8d055f6 | 81 | if (flags & LOOPS_HAVE_PREHEADERS) |
82 | create_preheaders (loops, CP_SIMPLE_PREHEADERS); | |
6a606e3c | 83 | |
84 | /* Force all latches to have only single successor. */ | |
c8d055f6 | 85 | if (flags & LOOPS_HAVE_SIMPLE_LATCHES) |
86 | force_single_succ_latches (loops); | |
6a606e3c | 87 | |
88 | /* Mark irreducible loops. */ | |
c8d055f6 | 89 | if (flags & LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS) |
90 | mark_irreducible_loops (loops); | |
91 | ||
92 | if (flags & LOOPS_HAVE_MARKED_SINGLE_EXITS) | |
93 | mark_single_exit_loops (loops); | |
6a606e3c | 94 | |
95 | /* Dump loops. */ | |
3f5be5f4 | 96 | flow_loops_dump (loops, dump_file, NULL, 1); |
6a606e3c | 97 | |
98 | #ifdef ENABLE_CHECKING | |
0051c76a | 99 | verify_dominators (CDI_DOMINATORS); |
6a606e3c | 100 | verify_loop_structure (loops); |
101 | #endif | |
102 | ||
103 | return loops; | |
104 | } | |
105 | ||
106 | /* Finalize loop optimizer. */ | |
107 | void | |
3f5be5f4 | 108 | loop_optimizer_finalize (struct loops *loops) |
6a606e3c | 109 | { |
f9cce2dc | 110 | unsigned i; |
6a606e3c | 111 | |
f9cce2dc | 112 | if (!loops) |
113 | return; | |
114 | ||
115 | for (i = 1; i < loops->num; i++) | |
116 | if (loops->parray[i]) | |
117 | free_simple_loop_desc (loops->parray[i]); | |
6a606e3c | 118 | |
6a606e3c | 119 | /* Clean up. */ |
120 | flow_loops_free (loops); | |
121 | free (loops); | |
3ad4992f | 122 | |
6a606e3c | 123 | /* Checking. */ |
124 | #ifdef ENABLE_CHECKING | |
125 | verify_flow_info (); | |
126 | #endif | |
127 | } | |
0526a3ff | 128 | |
77fce4cd | 129 | \f |
0526a3ff | 130 | /* Gate for the RTL loop superpass. The actual passes are subpasses. |
131 | See passes.c for more on that. */ | |
132 | ||
77fce4cd | 133 | static bool |
134 | gate_handle_loop2 (void) | |
135 | { | |
136 | return (optimize > 0 && flag_loop_optimize2 | |
137 | && (flag_move_loop_invariants | |
138 | || flag_unswitch_loops | |
139 | || flag_peel_loops | |
140 | || flag_unroll_loops | |
141 | || flag_branch_on_count_reg)); | |
142 | } | |
143 | ||
0526a3ff | 144 | struct tree_opt_pass pass_loop2 = |
77fce4cd | 145 | { |
0526a3ff | 146 | "loop2", /* name */ |
147 | gate_handle_loop2, /* gate */ | |
148 | NULL, /* execute */ | |
149 | NULL, /* sub */ | |
150 | NULL, /* next */ | |
151 | 0, /* static_pass_number */ | |
152 | TV_LOOP, /* tv_id */ | |
153 | 0, /* properties_required */ | |
154 | 0, /* properties_provided */ | |
155 | 0, /* properties_destroyed */ | |
156 | 0, /* todo_flags_start */ | |
157 | TODO_dump_func | | |
158 | TODO_ggc_collect, /* todo_flags_finish */ | |
159 | 'L' /* letter */ | |
160 | }; | |
77fce4cd | 161 | |
0526a3ff | 162 | \f |
163 | /* Initialization of the RTL loop passes. */ | |
164 | static void | |
165 | rtl_loop_init (void) | |
166 | { | |
77fce4cd | 167 | if (dump_file) |
168 | dump_flow_info (dump_file); | |
169 | ||
170 | /* Initialize structures for layout changes. */ | |
171 | cfg_layout_initialize (0); | |
172 | ||
3f5be5f4 | 173 | current_loops = loop_optimizer_init (LOOPS_NORMAL); |
0526a3ff | 174 | } |
77fce4cd | 175 | |
0526a3ff | 176 | struct tree_opt_pass pass_rtl_loop_init = |
177 | { | |
228967a9 | 178 | "loop2_init", /* name */ |
0526a3ff | 179 | NULL, /* gate */ |
180 | rtl_loop_init, /* execute */ | |
181 | NULL, /* sub */ | |
182 | NULL, /* next */ | |
183 | 0, /* static_pass_number */ | |
184 | TV_LOOP, /* tv_id */ | |
185 | 0, /* properties_required */ | |
186 | 0, /* properties_provided */ | |
187 | 0, /* properties_destroyed */ | |
188 | 0, /* todo_flags_start */ | |
189 | TODO_dump_func, /* todo_flags_finish */ | |
190 | 'L' /* letter */ | |
191 | }; | |
77fce4cd | 192 | |
0526a3ff | 193 | \f |
194 | /* Finalization of the RTL loop passes. */ | |
195 | static void | |
196 | rtl_loop_done (void) | |
197 | { | |
198 | basic_block bb; | |
77fce4cd | 199 | |
0526a3ff | 200 | if (current_loops) |
3f5be5f4 | 201 | loop_optimizer_finalize (current_loops); |
77fce4cd | 202 | |
203 | free_dominance_info (CDI_DOMINATORS); | |
204 | ||
205 | /* Finalize layout changes. */ | |
206 | FOR_EACH_BB (bb) | |
207 | if (bb->next_bb != EXIT_BLOCK_PTR) | |
208 | bb->aux = bb->next_bb; | |
209 | cfg_layout_finalize (); | |
210 | ||
211 | cleanup_cfg (CLEANUP_EXPENSIVE); | |
212 | delete_trivially_dead_insns (get_insns (), max_reg_num ()); | |
213 | reg_scan (get_insns (), max_reg_num ()); | |
214 | if (dump_file) | |
215 | dump_flow_info (dump_file); | |
0526a3ff | 216 | |
217 | current_loops = NULL; | |
77fce4cd | 218 | } |
219 | ||
0526a3ff | 220 | struct tree_opt_pass pass_rtl_loop_done = |
77fce4cd | 221 | { |
228967a9 | 222 | "loop2_done", /* name */ |
0526a3ff | 223 | NULL, /* gate */ |
224 | rtl_loop_done, /* execute */ | |
77fce4cd | 225 | NULL, /* sub */ |
226 | NULL, /* next */ | |
227 | 0, /* static_pass_number */ | |
228 | TV_LOOP, /* tv_id */ | |
229 | 0, /* properties_required */ | |
230 | 0, /* properties_provided */ | |
231 | 0, /* properties_destroyed */ | |
232 | 0, /* todo_flags_start */ | |
0526a3ff | 233 | TODO_dump_func, /* todo_flags_finish */ |
234 | 'L' /* letter */ | |
235 | }; | |
236 | ||
237 | \f | |
238 | /* Loop invariant code motion. */ | |
228967a9 | 239 | static bool |
240 | gate_rtl_move_loop_invariants (void) | |
241 | { | |
242 | return flag_move_loop_invariants; | |
243 | } | |
244 | ||
0526a3ff | 245 | static void |
246 | rtl_move_loop_invariants (void) | |
247 | { | |
228967a9 | 248 | if (current_loops) |
0526a3ff | 249 | move_loop_invariants (current_loops); |
250 | } | |
251 | ||
252 | struct tree_opt_pass pass_rtl_move_loop_invariants = | |
253 | { | |
228967a9 | 254 | "loop2_invariant", /* name */ |
255 | gate_rtl_move_loop_invariants, /* gate */ | |
0526a3ff | 256 | rtl_move_loop_invariants, /* execute */ |
257 | NULL, /* sub */ | |
258 | NULL, /* next */ | |
259 | 0, /* static_pass_number */ | |
260 | TV_LOOP, /* tv_id */ | |
261 | 0, /* properties_required */ | |
262 | 0, /* properties_provided */ | |
263 | 0, /* properties_destroyed */ | |
264 | 0, /* todo_flags_start */ | |
265 | TODO_dump_func, /* todo_flags_finish */ | |
266 | 'L' /* letter */ | |
267 | }; | |
268 | ||
269 | \f | |
270 | /* Loop unswitching for RTL. */ | |
228967a9 | 271 | static bool |
272 | gate_rtl_unswitch (void) | |
273 | { | |
274 | return flag_unswitch_loops; | |
275 | } | |
276 | ||
0526a3ff | 277 | static void |
278 | rtl_unswitch (void) | |
279 | { | |
228967a9 | 280 | if (current_loops) |
0526a3ff | 281 | unswitch_loops (current_loops); |
282 | } | |
283 | ||
284 | struct tree_opt_pass pass_rtl_unswitch = | |
285 | { | |
228967a9 | 286 | "loop2_unswitch", /* name */ |
287 | gate_rtl_unswitch, /* gate */ | |
0526a3ff | 288 | rtl_unswitch, /* execute */ |
289 | NULL, /* sub */ | |
290 | NULL, /* next */ | |
291 | 0, /* static_pass_number */ | |
292 | TV_LOOP, /* tv_id */ | |
293 | 0, /* properties_required */ | |
294 | 0, /* properties_provided */ | |
295 | 0, /* properties_destroyed */ | |
296 | 0, /* todo_flags_start */ | |
297 | TODO_dump_func, /* todo_flags_finish */ | |
298 | 'L' /* letter */ | |
299 | }; | |
300 | ||
301 | \f | |
302 | /* Loop unswitching for RTL. */ | |
228967a9 | 303 | static bool |
304 | gate_rtl_unroll_and_peel_loops (void) | |
305 | { | |
306 | return (flag_peel_loops || flag_unroll_loops || flag_unroll_all_loops); | |
307 | } | |
308 | ||
0526a3ff | 309 | static void |
310 | rtl_unroll_and_peel_loops (void) | |
311 | { | |
228967a9 | 312 | if (current_loops) |
0526a3ff | 313 | { |
314 | int flags = 0; | |
315 | ||
316 | if (flag_peel_loops) | |
317 | flags |= UAP_PEEL; | |
318 | if (flag_unroll_loops) | |
319 | flags |= UAP_UNROLL; | |
320 | if (flag_unroll_all_loops) | |
321 | flags |= UAP_UNROLL_ALL; | |
322 | ||
323 | unroll_and_peel_loops (current_loops, flags); | |
324 | } | |
325 | } | |
326 | ||
327 | struct tree_opt_pass pass_rtl_unroll_and_peel_loops = | |
328 | { | |
228967a9 | 329 | "loop2_unroll", /* name */ |
330 | gate_rtl_unroll_and_peel_loops, /* gate */ | |
0526a3ff | 331 | rtl_unroll_and_peel_loops, /* execute */ |
332 | NULL, /* sub */ | |
333 | NULL, /* next */ | |
334 | 0, /* static_pass_number */ | |
335 | TV_LOOP, /* tv_id */ | |
336 | 0, /* properties_required */ | |
337 | 0, /* properties_provided */ | |
338 | 0, /* properties_destroyed */ | |
339 | 0, /* todo_flags_start */ | |
340 | TODO_dump_func, /* todo_flags_finish */ | |
341 | 'L' /* letter */ | |
342 | }; | |
343 | ||
344 | \f | |
345 | /* The doloop optimization. */ | |
228967a9 | 346 | static bool |
347 | gate_rtl_doloop (void) | |
348 | { | |
349 | #ifdef HAVE_doloop_end | |
350 | return (flag_branch_on_count_reg && HAVE_doloop_end); | |
351 | #else | |
352 | return 0; | |
353 | #endif | |
354 | } | |
355 | ||
0526a3ff | 356 | static void |
357 | rtl_doloop (void) | |
358 | { | |
359 | #ifdef HAVE_doloop_end | |
228967a9 | 360 | if (current_loops) |
0526a3ff | 361 | doloop_optimize_loops (current_loops); |
362 | #endif | |
363 | } | |
364 | ||
365 | struct tree_opt_pass pass_rtl_doloop = | |
366 | { | |
228967a9 | 367 | "loop2_doloop", /* name */ |
368 | gate_rtl_doloop, /* gate */ | |
0526a3ff | 369 | rtl_doloop, /* execute */ |
370 | NULL, /* sub */ | |
371 | NULL, /* next */ | |
372 | 0, /* static_pass_number */ | |
373 | TV_LOOP, /* tv_id */ | |
374 | 0, /* properties_required */ | |
375 | 0, /* properties_provided */ | |
376 | 0, /* properties_destroyed */ | |
377 | 0, /* todo_flags_start */ | |
378 | TODO_dump_func, /* todo_flags_finish */ | |
77fce4cd | 379 | 'L' /* letter */ |
380 | }; | |
381 |