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689ba89d | 1 | /* Perform doloop optimizations |
c6c81aa6 | 2 | Copyright (C) 2004, 2005 Free Software Foundation, Inc. |
689ba89d ZD |
3 | Based on code by Michael P. Hayes (m.hayes@elec.canterbury.ac.nz) |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING. If not, write to the Free | |
366ccddb KC |
19 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
20 | 02110-1301, USA. */ | |
689ba89d ZD |
21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "rtl.h" | |
27 | #include "flags.h" | |
28 | #include "expr.h" | |
29 | #include "hard-reg-set.h" | |
30 | #include "basic-block.h" | |
31 | #include "toplev.h" | |
32 | #include "tm_p.h" | |
33 | #include "cfgloop.h" | |
34 | #include "output.h" | |
35 | #include "params.h" | |
a71a498d | 36 | #include "target.h" |
689ba89d ZD |
37 | |
38 | /* This module is used to modify loops with a determinable number of | |
39 | iterations to use special low-overhead looping instructions. | |
40 | ||
41 | It first validates whether the loop is well behaved and has a | |
42 | determinable number of iterations (either at compile or run-time). | |
43 | It then modifies the loop to use a low-overhead looping pattern as | |
44 | follows: | |
45 | ||
46 | 1. A pseudo register is allocated as the loop iteration counter. | |
47 | ||
48 | 2. The number of loop iterations is calculated and is stored | |
49 | in the loop counter. | |
50 | ||
51 | 3. At the end of the loop, the jump insn is replaced by the | |
52 | doloop_end pattern. The compare must remain because it might be | |
53 | used elsewhere. If the loop-variable or condition register are | |
54 | used elsewhere, they will be eliminated by flow. | |
55 | ||
56 | 4. An optional doloop_begin pattern is inserted at the top of the | |
57 | loop. | |
58 | ||
59 | TODO The optimization should only performed when either the biv used for exit | |
60 | condition is unused at all except for the exit test, or if we do not have to | |
61 | change its value, since otherwise we have to add a new induction variable, | |
62 | which usually will not pay up (unless the cost of the doloop pattern is | |
63 | somehow extremely lower than the cost of compare & jump, or unless the bct | |
64 | register cannot be used for anything else but doloop -- ??? detect these | |
65 | cases). */ | |
66 | ||
67 | #ifdef HAVE_doloop_end | |
68 | ||
69 | /* Return the loop termination condition for PATTERN or zero | |
70 | if it is not a decrement and branch jump insn. */ | |
71 | ||
75c70254 | 72 | rtx |
689ba89d ZD |
73 | doloop_condition_get (rtx pattern) |
74 | { | |
75 | rtx cmp; | |
76 | rtx inc; | |
77 | rtx reg; | |
75c70254 | 78 | rtx inc_src; |
689ba89d ZD |
79 | rtx condition; |
80 | ||
81 | /* The canonical doloop pattern we expect is: | |
82 | ||
83 | (parallel [(set (pc) (if_then_else (condition) | |
84 | (label_ref (label)) | |
85 | (pc))) | |
86 | (set (reg) (plus (reg) (const_int -1))) | |
87 | (additional clobbers and uses)]) | |
88 | ||
75c70254 SB |
89 | Some targets (IA-64) wrap the set of the loop counter in |
90 | an if_then_else too. | |
91 | ||
92 | In summary, the branch must be the first entry of the | |
93 | parallel (also required by jump.c), and the second | |
94 | entry of the parallel must be a set of the loop counter | |
95 | register. */ | |
689ba89d ZD |
96 | |
97 | if (GET_CODE (pattern) != PARALLEL) | |
98 | return 0; | |
99 | ||
100 | cmp = XVECEXP (pattern, 0, 0); | |
101 | inc = XVECEXP (pattern, 0, 1); | |
102 | ||
103 | /* Check for (set (reg) (something)). */ | |
75c70254 | 104 | if (GET_CODE (inc) != SET) |
689ba89d | 105 | return 0; |
689ba89d | 106 | reg = SET_DEST (inc); |
75c70254 SB |
107 | if (! REG_P (reg)) |
108 | return 0; | |
109 | ||
110 | /* Check if something = (plus (reg) (const_int -1)). | |
111 | On IA-64, this decrement is wrapped in an if_then_else. */ | |
112 | inc_src = SET_SRC (inc); | |
113 | if (GET_CODE (inc_src) == IF_THEN_ELSE) | |
114 | inc_src = XEXP (inc_src, 1); | |
115 | if (GET_CODE (inc_src) != PLUS | |
116 | || XEXP (inc_src, 0) != reg | |
117 | || XEXP (inc_src, 1) != constm1_rtx) | |
118 | return 0; | |
689ba89d ZD |
119 | |
120 | /* Check for (set (pc) (if_then_else (condition) | |
121 | (label_ref (label)) | |
122 | (pc))). */ | |
123 | if (GET_CODE (cmp) != SET | |
124 | || SET_DEST (cmp) != pc_rtx | |
125 | || GET_CODE (SET_SRC (cmp)) != IF_THEN_ELSE | |
126 | || GET_CODE (XEXP (SET_SRC (cmp), 1)) != LABEL_REF | |
127 | || XEXP (SET_SRC (cmp), 2) != pc_rtx) | |
128 | return 0; | |
129 | ||
130 | /* Extract loop termination condition. */ | |
131 | condition = XEXP (SET_SRC (cmp), 0); | |
132 | ||
75c70254 SB |
133 | /* We expect a GE or NE comparison with 0 or 1. */ |
134 | if ((GET_CODE (condition) != GE | |
135 | && GET_CODE (condition) != NE) | |
136 | || (XEXP (condition, 1) != const0_rtx | |
137 | && XEXP (condition, 1) != const1_rtx)) | |
689ba89d ZD |
138 | return 0; |
139 | ||
75c70254 SB |
140 | if ((XEXP (condition, 0) == reg) |
141 | || (GET_CODE (XEXP (condition, 0)) == PLUS | |
142 | && XEXP (XEXP (condition, 0), 0) == reg)) | |
689ba89d ZD |
143 | return condition; |
144 | ||
145 | /* ??? If a machine uses a funny comparison, we could return a | |
1ae58c30 | 146 | canonicalized form here. */ |
689ba89d ZD |
147 | |
148 | return 0; | |
149 | } | |
150 | ||
151 | /* Return nonzero if the loop specified by LOOP is suitable for | |
152 | the use of special low-overhead looping instructions. DESC | |
153 | describes the number of iterations of the loop. */ | |
154 | ||
155 | static bool | |
156 | doloop_valid_p (struct loop *loop, struct niter_desc *desc) | |
157 | { | |
158 | basic_block *body = get_loop_body (loop), bb; | |
159 | rtx insn; | |
160 | unsigned i; | |
7600f094 | 161 | bool result = true; |
689ba89d ZD |
162 | |
163 | /* Check for loops that may not terminate under special conditions. */ | |
164 | if (!desc->simple_p | |
165 | || desc->assumptions | |
166 | || desc->infinite) | |
167 | { | |
168 | /* There are some cases that would require a special attention. | |
169 | For example if the comparison is LEU and the comparison value | |
170 | is UINT_MAX then the loop will not terminate. Similarly, if the | |
171 | comparison code is GEU and the comparison value is 0, the | |
172 | loop will not terminate. | |
173 | ||
174 | If the absolute increment is not 1, the loop can be infinite | |
175 | even with LTU/GTU, e.g. for (i = 3; i > 0; i -= 2) | |
176 | ||
177 | ??? We could compute these conditions at run-time and have a | |
178 | additional jump around the loop to ensure an infinite loop. | |
179 | However, it is very unlikely that this is the intended | |
180 | behavior of the loop and checking for these rare boundary | |
181 | conditions would pessimize all other code. | |
182 | ||
183 | If the loop is executed only a few times an extra check to | |
184 | restart the loop could use up most of the benefits of using a | |
185 | count register loop. Note however, that normally, this | |
186 | restart branch would never execute, so it could be predicted | |
187 | well by the CPU. We should generate the pessimistic code by | |
188 | default, and have an option, e.g. -funsafe-loops that would | |
189 | enable count-register loops in this case. */ | |
190 | if (dump_file) | |
191 | fprintf (dump_file, "Doloop: Possible infinite iteration case.\n"); | |
7600f094 AP |
192 | result = false; |
193 | goto cleanup; | |
689ba89d ZD |
194 | } |
195 | ||
196 | for (i = 0; i < loop->num_nodes; i++) | |
197 | { | |
198 | bb = body[i]; | |
199 | ||
200 | for (insn = BB_HEAD (bb); | |
201 | insn != NEXT_INSN (BB_END (bb)); | |
202 | insn = NEXT_INSN (insn)) | |
203 | { | |
a71a498d AS |
204 | /* Different targets have different necessities for low-overhead |
205 | looping. Call the back end for each instruction within the loop | |
e7e64a25 AS |
206 | to let it decide whether the insn prohibits a low-overhead loop. |
207 | It will then return the cause for it to emit to the dump file. */ | |
208 | const char * invalid = targetm.invalid_within_doloop (insn); | |
209 | if (invalid) | |
210 | { | |
211 | if (dump_file) | |
212 | fprintf (dump_file, "Doloop: %s\n", invalid); | |
7600f094 AP |
213 | result = false; |
214 | goto cleanup; | |
e7e64a25 | 215 | } |
689ba89d ZD |
216 | } |
217 | } | |
7600f094 AP |
218 | result = true; |
219 | ||
220 | cleanup: | |
689ba89d ZD |
221 | free (body); |
222 | ||
7600f094 | 223 | return result; |
689ba89d ZD |
224 | } |
225 | ||
226 | /* Adds test of COND jumping to DEST to the end of BB. */ | |
227 | ||
228 | static void | |
229 | add_test (rtx cond, basic_block bb, basic_block dest) | |
230 | { | |
231 | rtx seq, jump, label; | |
232 | enum machine_mode mode; | |
233 | rtx op0 = XEXP (cond, 0), op1 = XEXP (cond, 1); | |
234 | enum rtx_code code = GET_CODE (cond); | |
235 | ||
236 | mode = GET_MODE (XEXP (cond, 0)); | |
237 | if (mode == VOIDmode) | |
238 | mode = GET_MODE (XEXP (cond, 1)); | |
239 | ||
240 | start_sequence (); | |
241 | op0 = force_operand (op0, NULL_RTX); | |
242 | op1 = force_operand (op1, NULL_RTX); | |
243 | label = block_label (dest); | |
244 | do_compare_rtx_and_jump (op0, op1, code, 0, mode, NULL_RTX, NULL_RTX, label); | |
245 | ||
246 | jump = get_last_insn (); | |
247 | JUMP_LABEL (jump) = label; | |
248 | ||
249 | /* The jump is supposed to handle an unlikely special case. */ | |
250 | REG_NOTES (jump) | |
251 | = gen_rtx_EXPR_LIST (REG_BR_PROB, | |
147d77b6 | 252 | const0_rtx, REG_NOTES (jump)); |
689ba89d ZD |
253 | |
254 | LABEL_NUSES (label)++; | |
255 | ||
256 | seq = get_insns (); | |
257 | end_sequence (); | |
258 | emit_insn_after (seq, BB_END (bb)); | |
259 | } | |
260 | ||
261 | /* Modify the loop to use the low-overhead looping insn where LOOP | |
262 | describes the loop, DESC describes the number of iterations of the | |
263 | loop, and DOLOOP_INSN is the low-overhead looping insn to emit at the | |
264 | end of the loop. CONDITION is the condition separated from the | |
a82bbcbb | 265 | DOLOOP_SEQ. COUNT is the number of iterations of the LOOP. */ |
689ba89d ZD |
266 | |
267 | static void | |
268 | doloop_modify (struct loop *loop, struct niter_desc *desc, | |
a82bbcbb | 269 | rtx doloop_seq, rtx condition, rtx count) |
689ba89d ZD |
270 | { |
271 | rtx counter_reg; | |
a82bbcbb | 272 | rtx tmp, noloop = NULL_RTX; |
689ba89d ZD |
273 | rtx sequence; |
274 | rtx jump_insn; | |
275 | rtx jump_label; | |
276 | int nonneg = 0, irr; | |
277 | bool increment_count; | |
278 | basic_block loop_end = desc->out_edge->src; | |
a82bbcbb | 279 | enum machine_mode mode; |
689ba89d ZD |
280 | |
281 | jump_insn = BB_END (loop_end); | |
282 | ||
283 | if (dump_file) | |
284 | { | |
285 | fprintf (dump_file, "Doloop: Inserting doloop pattern ("); | |
286 | if (desc->const_iter) | |
287 | fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC, desc->niter); | |
288 | else | |
289 | fputs ("runtime", dump_file); | |
290 | fputs (" iterations).\n", dump_file); | |
291 | } | |
292 | ||
293 | /* Discard original jump to continue loop. The original compare | |
294 | result may still be live, so it cannot be discarded explicitly. */ | |
295 | delete_insn (jump_insn); | |
296 | ||
297 | counter_reg = XEXP (condition, 0); | |
298 | if (GET_CODE (counter_reg) == PLUS) | |
299 | counter_reg = XEXP (counter_reg, 0); | |
a82bbcbb | 300 | mode = GET_MODE (counter_reg); |
689ba89d | 301 | |
689ba89d ZD |
302 | increment_count = false; |
303 | switch (GET_CODE (condition)) | |
304 | { | |
305 | case NE: | |
306 | /* Currently only NE tests against zero and one are supported. */ | |
b5e624c6 NS |
307 | noloop = XEXP (condition, 1); |
308 | if (noloop != const0_rtx) | |
689ba89d | 309 | { |
b5e624c6 | 310 | gcc_assert (noloop == const1_rtx); |
689ba89d | 311 | increment_count = true; |
689ba89d | 312 | } |
689ba89d ZD |
313 | break; |
314 | ||
315 | case GE: | |
316 | /* Currently only GE tests against zero are supported. */ | |
b5e624c6 | 317 | gcc_assert (XEXP (condition, 1) == const0_rtx); |
689ba89d ZD |
318 | |
319 | noloop = constm1_rtx; | |
320 | ||
321 | /* The iteration count does not need incrementing for a GE test. */ | |
322 | increment_count = false; | |
323 | ||
324 | /* Determine if the iteration counter will be non-negative. | |
325 | Note that the maximum value loaded is iterations_max - 1. */ | |
326 | if (desc->niter_max | |
327 | <= ((unsigned HOST_WIDEST_INT) 1 | |
a82bbcbb | 328 | << (GET_MODE_BITSIZE (mode) - 1))) |
689ba89d ZD |
329 | nonneg = 1; |
330 | break; | |
331 | ||
1c43d3ca | 332 | /* Abort if an invalid doloop pattern has been generated. */ |
8127d0e0 | 333 | default: |
b5e624c6 | 334 | gcc_unreachable (); |
689ba89d ZD |
335 | } |
336 | ||
337 | if (increment_count) | |
a82bbcbb | 338 | count = simplify_gen_binary (PLUS, mode, count, const1_rtx); |
689ba89d ZD |
339 | |
340 | /* Insert initialization of the count register into the loop header. */ | |
341 | start_sequence (); | |
342 | tmp = force_operand (count, counter_reg); | |
343 | convert_move (counter_reg, tmp, 1); | |
344 | sequence = get_insns (); | |
345 | end_sequence (); | |
346 | emit_insn_after (sequence, BB_END (loop_preheader_edge (loop)->src)); | |
347 | ||
348 | if (desc->noloop_assumptions) | |
349 | { | |
30d3fc60 | 350 | rtx ass = copy_rtx (desc->noloop_assumptions); |
689ba89d ZD |
351 | basic_block preheader = loop_preheader_edge (loop)->src; |
352 | basic_block set_zero | |
353 | = loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX); | |
354 | basic_block new_preheader | |
355 | = loop_split_edge_with (loop_preheader_edge (loop), NULL_RTX); | |
356 | basic_block bb; | |
357 | edge te; | |
358 | gcov_type cnt; | |
359 | ||
360 | /* Expand the condition testing the assumptions and if it does not pass, | |
361 | reset the count register to 0. */ | |
362 | add_test (XEXP (ass, 0), preheader, set_zero); | |
c5cbcccf ZD |
363 | single_succ_edge (preheader)->flags &= ~EDGE_FALLTHRU; |
364 | cnt = single_succ_edge (preheader)->count; | |
365 | single_succ_edge (preheader)->probability = 0; | |
366 | single_succ_edge (preheader)->count = 0; | |
367 | irr = single_succ_edge (preheader)->flags & EDGE_IRREDUCIBLE_LOOP; | |
689ba89d ZD |
368 | te = make_edge (preheader, new_preheader, EDGE_FALLTHRU | irr); |
369 | te->probability = REG_BR_PROB_BASE; | |
370 | te->count = cnt; | |
371 | set_immediate_dominator (CDI_DOMINATORS, new_preheader, preheader); | |
372 | ||
373 | set_zero->count = 0; | |
374 | set_zero->frequency = 0; | |
375 | ||
376 | for (ass = XEXP (ass, 1); ass; ass = XEXP (ass, 1)) | |
377 | { | |
378 | bb = loop_split_edge_with (te, NULL_RTX); | |
c5cbcccf | 379 | te = single_succ_edge (bb); |
689ba89d ZD |
380 | add_test (XEXP (ass, 0), bb, set_zero); |
381 | make_edge (bb, set_zero, irr); | |
382 | } | |
383 | ||
384 | start_sequence (); | |
385 | convert_move (counter_reg, noloop, 0); | |
386 | sequence = get_insns (); | |
387 | end_sequence (); | |
388 | emit_insn_after (sequence, BB_END (set_zero)); | |
389 | } | |
390 | ||
391 | /* Some targets (eg, C4x) need to initialize special looping | |
392 | registers. */ | |
393 | #ifdef HAVE_doloop_begin | |
394 | { | |
395 | rtx init; | |
396 | unsigned level = get_loop_level (loop) + 1; | |
397 | init = gen_doloop_begin (counter_reg, | |
398 | desc->const_iter ? desc->niter_expr : const0_rtx, | |
1984d2e8 | 399 | GEN_INT (desc->niter_max), |
689ba89d ZD |
400 | GEN_INT (level)); |
401 | if (init) | |
402 | { | |
403 | start_sequence (); | |
404 | emit_insn (init); | |
405 | sequence = get_insns (); | |
406 | end_sequence (); | |
407 | emit_insn_after (sequence, BB_END (loop_preheader_edge (loop)->src)); | |
408 | } | |
409 | } | |
410 | #endif | |
411 | ||
412 | /* Insert the new low-overhead looping insn. */ | |
413 | emit_jump_insn_after (doloop_seq, BB_END (loop_end)); | |
414 | jump_insn = BB_END (loop_end); | |
415 | jump_label = block_label (desc->in_edge->dest); | |
416 | JUMP_LABEL (jump_insn) = jump_label; | |
417 | LABEL_NUSES (jump_label)++; | |
418 | ||
419 | /* Ensure the right fallthru edge is marked, for case we have reversed | |
420 | the condition. */ | |
421 | desc->in_edge->flags &= ~EDGE_FALLTHRU; | |
422 | desc->out_edge->flags |= EDGE_FALLTHRU; | |
423 | ||
424 | /* Add a REG_NONNEG note if the actual or estimated maximum number | |
425 | of iterations is non-negative. */ | |
426 | if (nonneg) | |
427 | { | |
428 | REG_NOTES (jump_insn) | |
429 | = gen_rtx_EXPR_LIST (REG_NONNEG, NULL_RTX, REG_NOTES (jump_insn)); | |
430 | } | |
431 | } | |
432 | ||
433 | /* Process loop described by LOOP validating that the loop is suitable for | |
434 | conversion to use a low overhead looping instruction, replacing the jump | |
435 | insn where suitable. Returns true if the loop was successfully | |
436 | modified. */ | |
437 | ||
438 | static bool | |
439 | doloop_optimize (struct loop *loop) | |
440 | { | |
441 | enum machine_mode mode; | |
442 | rtx doloop_seq, doloop_pat, doloop_reg; | |
a82bbcbb | 443 | rtx iterations, count; |
689ba89d ZD |
444 | rtx iterations_max; |
445 | rtx start_label; | |
446 | rtx condition; | |
447 | unsigned level, est_niter; | |
448 | struct niter_desc *desc; | |
a82bbcbb ZD |
449 | unsigned word_mode_size; |
450 | unsigned HOST_WIDE_INT word_mode_max; | |
689ba89d ZD |
451 | |
452 | if (dump_file) | |
453 | fprintf (dump_file, "Doloop: Processing loop %d.\n", loop->num); | |
454 | ||
455 | iv_analysis_loop_init (loop); | |
456 | ||
457 | /* Find the simple exit of a LOOP. */ | |
458 | desc = get_simple_loop_desc (loop); | |
459 | ||
460 | /* Check that loop is a candidate for a low-overhead looping insn. */ | |
461 | if (!doloop_valid_p (loop, desc)) | |
462 | { | |
463 | if (dump_file) | |
464 | fprintf (dump_file, | |
465 | "Doloop: The loop is not suitable.\n"); | |
466 | return false; | |
467 | } | |
468 | mode = desc->mode; | |
469 | ||
470 | est_niter = 3; | |
471 | if (desc->const_iter) | |
472 | est_niter = desc->niter; | |
473 | /* If the estimate on number of iterations is reliable (comes from profile | |
474 | feedback), use it. Do not use it normally, since the expected number | |
475 | of iterations of an unrolled loop is 2. */ | |
476 | if (loop->header->count) | |
477 | est_niter = expected_loop_iterations (loop); | |
478 | ||
479 | if (est_niter < 3) | |
480 | { | |
481 | if (dump_file) | |
482 | fprintf (dump_file, | |
483 | "Doloop: Too few iterations (%u) to be profitable.\n", | |
484 | est_niter); | |
485 | return false; | |
486 | } | |
487 | ||
a82bbcbb | 488 | count = copy_rtx (desc->niter_expr); |
689ba89d ZD |
489 | iterations = desc->const_iter ? desc->niter_expr : const0_rtx; |
490 | iterations_max = GEN_INT (desc->niter_max); | |
491 | level = get_loop_level (loop) + 1; | |
492 | ||
493 | /* Generate looping insn. If the pattern FAILs then give up trying | |
494 | to modify the loop since there is some aspect the back-end does | |
495 | not like. */ | |
496 | start_label = block_label (desc->in_edge->dest); | |
497 | doloop_reg = gen_reg_rtx (mode); | |
498 | doloop_seq = gen_doloop_end (doloop_reg, iterations, iterations_max, | |
499 | GEN_INT (level), start_label); | |
a82bbcbb ZD |
500 | |
501 | word_mode_size = GET_MODE_BITSIZE (word_mode); | |
502 | word_mode_max | |
503 | = ((unsigned HOST_WIDE_INT) 1 << (word_mode_size - 1) << 1) - 1; | |
504 | if (! doloop_seq | |
505 | && mode != word_mode | |
506 | /* Before trying mode different from the one in that # of iterations is | |
507 | computed, we must be sure that the number of iterations fits into | |
508 | the new mode. */ | |
509 | && (word_mode_size >= GET_MODE_BITSIZE (mode) | |
510 | || desc->niter_max <= word_mode_max)) | |
689ba89d | 511 | { |
a82bbcbb ZD |
512 | if (word_mode_size > GET_MODE_BITSIZE (mode)) |
513 | { | |
514 | count = simplify_gen_unary (ZERO_EXTEND, word_mode, | |
a252f3e8 | 515 | count, mode); |
a82bbcbb ZD |
516 | iterations = simplify_gen_unary (ZERO_EXTEND, word_mode, |
517 | iterations, mode); | |
518 | iterations_max = simplify_gen_unary (ZERO_EXTEND, word_mode, | |
519 | iterations_max, mode); | |
520 | } | |
521 | else | |
522 | { | |
523 | count = lowpart_subreg (word_mode, count, mode); | |
524 | iterations = lowpart_subreg (word_mode, iterations, mode); | |
525 | iterations_max = lowpart_subreg (word_mode, iterations_max, mode); | |
526 | } | |
689ba89d ZD |
527 | PUT_MODE (doloop_reg, word_mode); |
528 | doloop_seq = gen_doloop_end (doloop_reg, iterations, iterations_max, | |
529 | GEN_INT (level), start_label); | |
530 | } | |
531 | if (! doloop_seq) | |
532 | { | |
533 | if (dump_file) | |
534 | fprintf (dump_file, | |
535 | "Doloop: Target unwilling to use doloop pattern!\n"); | |
536 | return false; | |
537 | } | |
538 | ||
539 | /* If multiple instructions were created, the last must be the | |
540 | jump instruction. Also, a raw define_insn may yield a plain | |
541 | pattern. */ | |
542 | doloop_pat = doloop_seq; | |
543 | if (INSN_P (doloop_pat)) | |
544 | { | |
545 | while (NEXT_INSN (doloop_pat) != NULL_RTX) | |
546 | doloop_pat = NEXT_INSN (doloop_pat); | |
4b4bf941 | 547 | if (JUMP_P (doloop_pat)) |
689ba89d ZD |
548 | doloop_pat = PATTERN (doloop_pat); |
549 | else | |
550 | doloop_pat = NULL_RTX; | |
551 | } | |
552 | ||
553 | if (! doloop_pat | |
554 | || ! (condition = doloop_condition_get (doloop_pat))) | |
555 | { | |
556 | if (dump_file) | |
557 | fprintf (dump_file, "Doloop: Unrecognizable doloop pattern!\n"); | |
558 | return false; | |
559 | } | |
560 | ||
a82bbcbb | 561 | doloop_modify (loop, desc, doloop_seq, condition, count); |
689ba89d ZD |
562 | return true; |
563 | } | |
564 | ||
565 | /* This is the main entry point. Process all LOOPS using doloop_optimize. */ | |
566 | ||
567 | void | |
568 | doloop_optimize_loops (struct loops *loops) | |
569 | { | |
570 | unsigned i; | |
571 | struct loop *loop; | |
572 | ||
573 | for (i = 1; i < loops->num; i++) | |
574 | { | |
575 | loop = loops->parray[i]; | |
576 | if (!loop) | |
577 | continue; | |
578 | ||
579 | doloop_optimize (loop); | |
580 | } | |
581 | ||
582 | iv_analysis_done (); | |
583 | ||
584 | #ifdef ENABLE_CHECKING | |
585 | verify_dominators (CDI_DOMINATORS); | |
586 | verify_loop_structure (loops); | |
587 | #endif | |
588 | } | |
589 | #endif /* HAVE_doloop_end */ | |
590 |