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9c7e2978 | 1 | /* Perform instruction reorganizations for delay slot filling. |
a5cad800 | 2 | Copyright (C) 1992, 93-98, 1999 Free Software Foundation, Inc. |
1923e516 | 3 | Contributed by Richard Kenner (kenner@vlsi1.ultra.nyu.edu). |
9c7e2978 RK |
4 | Hacked by Michael Tiemann (tiemann@cygnus.com). |
5 | ||
6 | This file is part of GNU CC. | |
7 | ||
8 | GNU CC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2, or (at your option) | |
11 | any later version. | |
12 | ||
13 | GNU CC is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with GNU CC; see the file COPYING. If not, write to | |
e99215a3 RK |
20 | the Free Software Foundation, 59 Temple Place - Suite 330, |
21 | Boston, MA 02111-1307, USA. */ | |
9c7e2978 | 22 | |
9c7e2978 RK |
23 | /* Instruction reorganization pass. |
24 | ||
25 | This pass runs after register allocation and final jump | |
26 | optimization. It should be the last pass to run before peephole. | |
27 | It serves primarily to fill delay slots of insns, typically branch | |
28 | and call insns. Other insns typically involve more complicated | |
6dc42e49 | 29 | interactions of data dependencies and resource constraints, and |
9c7e2978 RK |
30 | are better handled by scheduling before register allocation (by the |
31 | function `schedule_insns'). | |
32 | ||
33 | The Branch Penalty is the number of extra cycles that are needed to | |
34 | execute a branch insn. On an ideal machine, branches take a single | |
35 | cycle, and the Branch Penalty is 0. Several RISC machines approach | |
36 | branch delays differently: | |
37 | ||
38 | The MIPS and AMD 29000 have a single branch delay slot. Most insns | |
39 | (except other branches) can be used to fill this slot. When the | |
40 | slot is filled, two insns execute in two cycles, reducing the | |
41 | branch penalty to zero. | |
42 | ||
43 | The Motorola 88000 conditionally exposes its branch delay slot, | |
44 | so code is shorter when it is turned off, but will run faster | |
45 | when useful insns are scheduled there. | |
46 | ||
47 | The IBM ROMP has two forms of branch and call insns, both with and | |
48 | without a delay slot. Much like the 88k, insns not using the delay | |
49 | slot can be shorted (2 bytes vs. 4 bytes), but will run slowed. | |
50 | ||
51 | The SPARC always has a branch delay slot, but its effects can be | |
52 | annulled when the branch is not taken. This means that failing to | |
53 | find other sources of insns, we can hoist an insn from the branch | |
54 | target that would only be safe to execute knowing that the branch | |
55 | is taken. | |
56 | ||
35523fce JL |
57 | The HP-PA always has a branch delay slot. For unconditional branches |
58 | its effects can be annulled when the branch is taken. The effects | |
59 | of the delay slot in a conditional branch can be nullified for forward | |
60 | taken branches, or for untaken backward branches. This means | |
61 | we can hoist insns from the fall-through path for forward branches or | |
62 | steal insns from the target of backward branches. | |
63 | ||
18e765cb JL |
64 | The TMS320C3x and C4x have three branch delay slots. When the three |
65 | slots are filled, the branch penalty is zero. Most insns can fill the | |
66 | delay slots except jump insns. | |
67 | ||
9c7e2978 RK |
68 | Three techniques for filling delay slots have been implemented so far: |
69 | ||
70 | (1) `fill_simple_delay_slots' is the simplest, most efficient way | |
71 | to fill delay slots. This pass first looks for insns which come | |
72 | from before the branch and which are safe to execute after the | |
73 | branch. Then it searches after the insn requiring delay slots or, | |
74 | in the case of a branch, for insns that are after the point at | |
75 | which the branch merges into the fallthrough code, if such a point | |
76 | exists. When such insns are found, the branch penalty decreases | |
77 | and no code expansion takes place. | |
78 | ||
79 | (2) `fill_eager_delay_slots' is more complicated: it is used for | |
80 | scheduling conditional jumps, or for scheduling jumps which cannot | |
81 | be filled using (1). A machine need not have annulled jumps to use | |
82 | this strategy, but it helps (by keeping more options open). | |
83 | `fill_eager_delay_slots' tries to guess the direction the branch | |
84 | will go; if it guesses right 100% of the time, it can reduce the | |
c0e12601 | 85 | branch penalty as much as `fill_simple_delay_slots' does. If it |
9c7e2978 RK |
86 | guesses wrong 100% of the time, it might as well schedule nops (or |
87 | on the m88k, unexpose the branch slot). When | |
88 | `fill_eager_delay_slots' takes insns from the fall-through path of | |
89 | the jump, usually there is no code expansion; when it takes insns | |
90 | from the branch target, there is code expansion if it is not the | |
91 | only way to reach that target. | |
92 | ||
93 | (3) `relax_delay_slots' uses a set of rules to simplify code that | |
94 | has been reorganized by (1) and (2). It finds cases where | |
95 | conditional test can be eliminated, jumps can be threaded, extra | |
96 | insns can be eliminated, etc. It is the job of (1) and (2) to do a | |
97 | good job of scheduling locally; `relax_delay_slots' takes care of | |
98 | making the various individual schedules work well together. It is | |
99 | especially tuned to handle the control flow interactions of branch | |
100 | insns. It does nothing for insns with delay slots that do not | |
101 | branch. | |
102 | ||
103 | On machines that use CC0, we are very conservative. We will not make | |
104 | a copy of an insn involving CC0 since we want to maintain a 1-1 | |
d45cf215 | 105 | correspondence between the insn that sets and uses CC0. The insns are |
9c7e2978 RK |
106 | allowed to be separated by placing an insn that sets CC0 (but not an insn |
107 | that uses CC0; we could do this, but it doesn't seem worthwhile) in a | |
108 | delay slot. In that case, we point each insn at the other with REG_CC_USER | |
109 | and REG_CC_SETTER notes. Note that these restrictions affect very few | |
110 | machines because most RISC machines with delay slots will not use CC0 | |
111 | (the RT is the only known exception at this point). | |
112 | ||
113 | Not yet implemented: | |
114 | ||
115 | The Acorn Risc Machine can conditionally execute most insns, so | |
116 | it is profitable to move single insns into a position to execute | |
117 | based on the condition code of the previous insn. | |
118 | ||
119 | The HP-PA can conditionally nullify insns, providing a similar | |
120 | effect to the ARM, differing mostly in which insn is "in charge". */ | |
121 | ||
9c7e2978 | 122 | #include "config.h" |
670ee920 | 123 | #include "system.h" |
01198c2f | 124 | #include "toplev.h" |
9c7e2978 | 125 | #include "rtl.h" |
51549d76 | 126 | #include "expr.h" |
49ad7cfa | 127 | #include "function.h" |
9c7e2978 RK |
128 | #include "insn-config.h" |
129 | #include "conditions.h" | |
130 | #include "hard-reg-set.h" | |
131 | #include "basic-block.h" | |
132 | #include "regs.h" | |
133 | #include "insn-flags.h" | |
134 | #include "recog.h" | |
135 | #include "flags.h" | |
136 | #include "output.h" | |
137 | #include "obstack.h" | |
d80e9fd7 | 138 | #include "insn-attr.h" |
ca545bb5 | 139 | #include "resource.h" |
d80e9fd7 | 140 | |
b55f96db | 141 | |
d80e9fd7 | 142 | #ifdef DELAY_SLOTS |
9c7e2978 RK |
143 | |
144 | #define obstack_chunk_alloc xmalloc | |
145 | #define obstack_chunk_free free | |
146 | ||
9c7e2978 | 147 | #ifndef ANNUL_IFTRUE_SLOTS |
35523fce | 148 | #define eligible_for_annul_true(INSN, SLOTS, TRIAL, FLAGS) 0 |
9c7e2978 RK |
149 | #endif |
150 | #ifndef ANNUL_IFFALSE_SLOTS | |
35523fce | 151 | #define eligible_for_annul_false(INSN, SLOTS, TRIAL, FLAGS) 0 |
9c7e2978 RK |
152 | #endif |
153 | ||
154 | /* Insns which have delay slots that have not yet been filled. */ | |
155 | ||
156 | static struct obstack unfilled_slots_obstack; | |
157 | static rtx *unfilled_firstobj; | |
158 | ||
159 | /* Define macros to refer to the first and last slot containing unfilled | |
160 | insns. These are used because the list may move and its address | |
161 | should be recomputed at each use. */ | |
162 | ||
163 | #define unfilled_slots_base \ | |
164 | ((rtx *) obstack_base (&unfilled_slots_obstack)) | |
165 | ||
166 | #define unfilled_slots_next \ | |
167 | ((rtx *) obstack_next_free (&unfilled_slots_obstack)) | |
168 | ||
9c7e2978 RK |
169 | /* Points to the label before the end of the function. */ |
170 | static rtx end_of_function_label; | |
171 | ||
9c7e2978 RK |
172 | /* Mapping between INSN_UID's and position in the code since INSN_UID's do |
173 | not always monotonically increase. */ | |
174 | static int *uid_to_ruid; | |
175 | ||
176 | /* Highest valid index in `uid_to_ruid'. */ | |
177 | static int max_uid; | |
178 | ||
ab87f8c8 JL |
179 | static int stop_search_p PROTO((rtx, int)); |
180 | static int resource_conflicts_p PROTO((struct resources *, | |
181 | struct resources *)); | |
182 | static int insn_references_resource_p PROTO((rtx, struct resources *, int)); | |
183 | static int insn_sets_resource_p PROTO((rtx, struct resources *, int)); | |
184 | static rtx find_end_label PROTO((void)); | |
185 | static rtx emit_delay_sequence PROTO((rtx, rtx, int)); | |
186 | static rtx add_to_delay_list PROTO((rtx, rtx)); | |
187 | static rtx delete_from_delay_slot PROTO((rtx)); | |
188 | static void delete_scheduled_jump PROTO((rtx)); | |
189 | static void note_delay_statistics PROTO((int, int)); | |
190 | static rtx optimize_skip PROTO((rtx)); | |
191 | static int get_jump_flags PROTO((rtx, rtx)); | |
192 | static int rare_destination PROTO((rtx)); | |
193 | static int mostly_true_jump PROTO((rtx, rtx)); | |
194 | static rtx get_branch_condition PROTO((rtx, rtx)); | |
195 | static int condition_dominates_p PROTO((rtx, rtx)); | |
ca545bb5 BM |
196 | static int redirect_with_delay_slots_safe_p PROTO ((rtx, rtx, rtx)); |
197 | static int redirect_with_delay_list_safe_p PROTO ((rtx, rtx, rtx)); | |
198 | static int check_annul_list_true_false PROTO ((int, rtx)); | |
d8e8f346 RK |
199 | static rtx steal_delay_list_from_target PROTO((rtx, rtx, rtx, rtx, |
200 | struct resources *, | |
201 | struct resources *, | |
202 | struct resources *, | |
203 | int, int *, int *, rtx *)); | |
204 | static rtx steal_delay_list_from_fallthrough PROTO((rtx, rtx, rtx, rtx, | |
205 | struct resources *, | |
206 | struct resources *, | |
207 | struct resources *, | |
208 | int, int *, int *)); | |
ab87f8c8 JL |
209 | static void try_merge_delay_insns PROTO((rtx, rtx)); |
210 | static rtx redundant_insn PROTO((rtx, rtx, rtx)); | |
211 | static int own_thread_p PROTO((rtx, rtx, int)); | |
ab87f8c8 JL |
212 | static void update_block PROTO((rtx, rtx)); |
213 | static int reorg_redirect_jump PROTO((rtx, rtx)); | |
214 | static void update_reg_dead_notes PROTO((rtx, rtx)); | |
215 | static void fix_reg_dead_note PROTO((rtx, rtx)); | |
216 | static void update_reg_unused_notes PROTO((rtx, rtx)); | |
ab87f8c8 JL |
217 | static void fill_simple_delay_slots PROTO((int)); |
218 | static rtx fill_slots_from_thread PROTO((rtx, rtx, rtx, rtx, int, int, | |
219 | int, int, int *, rtx)); | |
220 | static void fill_eager_delay_slots PROTO((void)); | |
221 | static void relax_delay_slots PROTO((rtx)); | |
222 | static void make_return_insns PROTO((rtx)); | |
9c7e2978 RK |
223 | \f |
224 | /* Return TRUE if this insn should stop the search for insn to fill delay | |
225 | slots. LABELS_P indicates that labels should terminate the search. | |
226 | In all cases, jumps terminate the search. */ | |
227 | ||
228 | static int | |
229 | stop_search_p (insn, labels_p) | |
230 | rtx insn; | |
231 | int labels_p; | |
232 | { | |
233 | if (insn == 0) | |
234 | return 1; | |
235 | ||
236 | switch (GET_CODE (insn)) | |
237 | { | |
238 | case NOTE: | |
239 | case CALL_INSN: | |
240 | return 0; | |
241 | ||
242 | case CODE_LABEL: | |
243 | return labels_p; | |
244 | ||
245 | case JUMP_INSN: | |
246 | case BARRIER: | |
247 | return 1; | |
248 | ||
249 | case INSN: | |
250 | /* OK unless it contains a delay slot or is an `asm' insn of some type. | |
251 | We don't know anything about these. */ | |
252 | return (GET_CODE (PATTERN (insn)) == SEQUENCE | |
253 | || GET_CODE (PATTERN (insn)) == ASM_INPUT | |
254 | || asm_noperands (PATTERN (insn)) >= 0); | |
255 | ||
256 | default: | |
257 | abort (); | |
258 | } | |
259 | } | |
260 | \f | |
261 | /* Return TRUE if any resources are marked in both RES1 and RES2 or if either | |
262 | resource set contains a volatile memory reference. Otherwise, return FALSE. */ | |
263 | ||
264 | static int | |
265 | resource_conflicts_p (res1, res2) | |
266 | struct resources *res1, *res2; | |
267 | { | |
268 | if ((res1->cc && res2->cc) || (res1->memory && res2->memory) | |
8eae5ed6 | 269 | || (res1->unch_memory && res2->unch_memory) |
9c7e2978 RK |
270 | || res1->volatil || res2->volatil) |
271 | return 1; | |
272 | ||
273 | #ifdef HARD_REG_SET | |
274 | return (res1->regs & res2->regs) != HARD_CONST (0); | |
275 | #else | |
276 | { | |
277 | int i; | |
278 | ||
279 | for (i = 0; i < HARD_REG_SET_LONGS; i++) | |
280 | if ((res1->regs[i] & res2->regs[i]) != 0) | |
281 | return 1; | |
282 | return 0; | |
283 | } | |
284 | #endif | |
285 | } | |
286 | ||
287 | /* Return TRUE if any resource marked in RES, a `struct resources', is | |
ab63953e | 288 | referenced by INSN. If INCLUDE_DELAYED_EFFECTS is set, return if the called |
9c7e2978 RK |
289 | routine is using those resources. |
290 | ||
291 | We compute this by computing all the resources referenced by INSN and | |
292 | seeing if this conflicts with RES. It might be faster to directly check | |
293 | ourselves, and this is the way it used to work, but it means duplicating | |
294 | a large block of complex code. */ | |
295 | ||
296 | static int | |
674345b1 | 297 | insn_references_resource_p (insn, res, include_delayed_effects) |
9c7e2978 RK |
298 | register rtx insn; |
299 | register struct resources *res; | |
674345b1 | 300 | int include_delayed_effects; |
9c7e2978 RK |
301 | { |
302 | struct resources insn_res; | |
303 | ||
304 | CLEAR_RESOURCE (&insn_res); | |
674345b1 | 305 | mark_referenced_resources (insn, &insn_res, include_delayed_effects); |
9c7e2978 RK |
306 | return resource_conflicts_p (&insn_res, res); |
307 | } | |
308 | ||
309 | /* Return TRUE if INSN modifies resources that are marked in RES. | |
ab63953e | 310 | INCLUDE_DELAYED_EFFECTS is set if the actions of that routine should be |
9c7e2978 RK |
311 | included. CC0 is only modified if it is explicitly set; see comments |
312 | in front of mark_set_resources for details. */ | |
313 | ||
314 | static int | |
674345b1 | 315 | insn_sets_resource_p (insn, res, include_delayed_effects) |
9c7e2978 RK |
316 | register rtx insn; |
317 | register struct resources *res; | |
674345b1 | 318 | int include_delayed_effects; |
9c7e2978 RK |
319 | { |
320 | struct resources insn_sets; | |
321 | ||
322 | CLEAR_RESOURCE (&insn_sets); | |
674345b1 | 323 | mark_set_resources (insn, &insn_sets, 0, include_delayed_effects); |
9c7e2978 RK |
324 | return resource_conflicts_p (&insn_sets, res); |
325 | } | |
326 | \f | |
327 | /* Find a label at the end of the function or before a RETURN. If there is | |
328 | none, make one. */ | |
329 | ||
330 | static rtx | |
331 | find_end_label () | |
332 | { | |
333 | rtx insn; | |
334 | ||
335 | /* If we found one previously, return it. */ | |
336 | if (end_of_function_label) | |
337 | return end_of_function_label; | |
338 | ||
339 | /* Otherwise, see if there is a label at the end of the function. If there | |
340 | is, it must be that RETURN insns aren't needed, so that is our return | |
341 | label and we don't have to do anything else. */ | |
342 | ||
343 | insn = get_last_insn (); | |
344 | while (GET_CODE (insn) == NOTE | |
345 | || (GET_CODE (insn) == INSN | |
346 | && (GET_CODE (PATTERN (insn)) == USE | |
347 | || GET_CODE (PATTERN (insn)) == CLOBBER))) | |
348 | insn = PREV_INSN (insn); | |
349 | ||
e572bad3 JL |
350 | /* When a target threads its epilogue we might already have a |
351 | suitable return insn. If so put a label before it for the | |
352 | end_of_function_label. */ | |
353 | if (GET_CODE (insn) == BARRIER | |
354 | && GET_CODE (PREV_INSN (insn)) == JUMP_INSN | |
355 | && GET_CODE (PATTERN (PREV_INSN (insn))) == RETURN) | |
356 | { | |
357 | rtx temp = PREV_INSN (PREV_INSN (insn)); | |
358 | end_of_function_label = gen_label_rtx (); | |
359 | LABEL_NUSES (end_of_function_label) = 0; | |
360 | ||
0f41302f | 361 | /* Put the label before an USE insns that may proceed the RETURN insn. */ |
e572bad3 JL |
362 | while (GET_CODE (temp) == USE) |
363 | temp = PREV_INSN (temp); | |
364 | ||
365 | emit_label_after (end_of_function_label, temp); | |
366 | } | |
367 | ||
368 | else if (GET_CODE (insn) == CODE_LABEL) | |
369 | end_of_function_label = insn; | |
9c7e2978 RK |
370 | else |
371 | { | |
372 | /* Otherwise, make a new label and emit a RETURN and BARRIER, | |
373 | if needed. */ | |
374 | end_of_function_label = gen_label_rtx (); | |
375 | LABEL_NUSES (end_of_function_label) = 0; | |
376 | emit_label (end_of_function_label); | |
377 | #ifdef HAVE_return | |
378 | if (HAVE_return) | |
379 | { | |
5fcd63d0 | 380 | /* The return we make may have delay slots too. */ |
2dff5a06 RS |
381 | rtx insn = gen_return (); |
382 | insn = emit_jump_insn (insn); | |
9c7e2978 | 383 | emit_barrier (); |
5fcd63d0 JL |
384 | if (num_delay_slots (insn) > 0) |
385 | obstack_ptr_grow (&unfilled_slots_obstack, insn); | |
9c7e2978 RK |
386 | } |
387 | #endif | |
388 | } | |
389 | ||
390 | /* Show one additional use for this label so it won't go away until | |
391 | we are done. */ | |
392 | ++LABEL_NUSES (end_of_function_label); | |
393 | ||
394 | return end_of_function_label; | |
395 | } | |
396 | \f | |
397 | /* Put INSN and LIST together in a SEQUENCE rtx of LENGTH, and replace | |
398 | the pattern of INSN with the SEQUENCE. | |
399 | ||
400 | Chain the insns so that NEXT_INSN of each insn in the sequence points to | |
401 | the next and NEXT_INSN of the last insn in the sequence points to | |
402 | the first insn after the sequence. Similarly for PREV_INSN. This makes | |
403 | it easier to scan all insns. | |
404 | ||
405 | Returns the SEQUENCE that replaces INSN. */ | |
406 | ||
407 | static rtx | |
91a51951 | 408 | emit_delay_sequence (insn, list, length) |
9c7e2978 RK |
409 | rtx insn; |
410 | rtx list; | |
411 | int length; | |
9c7e2978 RK |
412 | { |
413 | register int i = 1; | |
414 | register rtx li; | |
415 | int had_barrier = 0; | |
416 | ||
38e01259 | 417 | /* Allocate the rtvec to hold the insns and the SEQUENCE. */ |
9c7e2978 | 418 | rtvec seqv = rtvec_alloc (length + 1); |
38a448ca | 419 | rtx seq = gen_rtx_SEQUENCE (VOIDmode, seqv); |
9c7e2978 RK |
420 | rtx seq_insn = make_insn_raw (seq); |
421 | rtx first = get_insns (); | |
422 | rtx last = get_last_insn (); | |
423 | ||
0f41302f | 424 | /* Make a copy of the insn having delay slots. */ |
9c7e2978 RK |
425 | rtx delay_insn = copy_rtx (insn); |
426 | ||
427 | /* If INSN is followed by a BARRIER, delete the BARRIER since it will only | |
428 | confuse further processing. Update LAST in case it was the last insn. | |
429 | We will put the BARRIER back in later. */ | |
430 | if (NEXT_INSN (insn) && GET_CODE (NEXT_INSN (insn)) == BARRIER) | |
431 | { | |
432 | delete_insn (NEXT_INSN (insn)); | |
433 | last = get_last_insn (); | |
434 | had_barrier = 1; | |
435 | } | |
436 | ||
437 | /* Splice our SEQUENCE into the insn stream where INSN used to be. */ | |
438 | NEXT_INSN (seq_insn) = NEXT_INSN (insn); | |
439 | PREV_INSN (seq_insn) = PREV_INSN (insn); | |
440 | ||
f5546425 JL |
441 | if (insn != last) |
442 | PREV_INSN (NEXT_INSN (seq_insn)) = seq_insn; | |
443 | ||
444 | if (insn != first) | |
445 | NEXT_INSN (PREV_INSN (seq_insn)) = seq_insn; | |
446 | ||
447 | /* Note the calls to set_new_first_and_last_insn must occur after | |
448 | SEQ_INSN has been completely spliced into the insn stream. | |
449 | ||
450 | Otherwise CUR_INSN_UID will get set to an incorrect value because | |
451 | set_new_first_and_last_insn will not find SEQ_INSN in the chain. */ | |
9c7e2978 RK |
452 | if (insn == last) |
453 | set_new_first_and_last_insn (first, seq_insn); | |
9c7e2978 RK |
454 | |
455 | if (insn == first) | |
456 | set_new_first_and_last_insn (seq_insn, last); | |
9c7e2978 RK |
457 | |
458 | /* Build our SEQUENCE and rebuild the insn chain. */ | |
459 | XVECEXP (seq, 0, 0) = delay_insn; | |
460 | INSN_DELETED_P (delay_insn) = 0; | |
461 | PREV_INSN (delay_insn) = PREV_INSN (seq_insn); | |
462 | ||
463 | for (li = list; li; li = XEXP (li, 1), i++) | |
464 | { | |
465 | rtx tem = XEXP (li, 0); | |
466 | rtx note; | |
467 | ||
468 | /* Show that this copy of the insn isn't deleted. */ | |
469 | INSN_DELETED_P (tem) = 0; | |
470 | ||
471 | XVECEXP (seq, 0, i) = tem; | |
472 | PREV_INSN (tem) = XVECEXP (seq, 0, i - 1); | |
473 | NEXT_INSN (XVECEXP (seq, 0, i - 1)) = tem; | |
474 | ||
475 | /* Remove any REG_DEAD notes because we can't rely on them now | |
476 | that the insn has been moved. */ | |
477 | for (note = REG_NOTES (tem); note; note = XEXP (note, 1)) | |
478 | if (REG_NOTE_KIND (note) == REG_DEAD) | |
479 | XEXP (note, 0) = const0_rtx; | |
480 | } | |
481 | ||
482 | NEXT_INSN (XVECEXP (seq, 0, length)) = NEXT_INSN (seq_insn); | |
483 | ||
f1f9081a RS |
484 | /* If the previous insn is a SEQUENCE, update the NEXT_INSN pointer on the |
485 | last insn in that SEQUENCE to point to us. Similarly for the first | |
486 | insn in the following insn if it is a SEQUENCE. */ | |
487 | ||
488 | if (PREV_INSN (seq_insn) && GET_CODE (PREV_INSN (seq_insn)) == INSN | |
489 | && GET_CODE (PATTERN (PREV_INSN (seq_insn))) == SEQUENCE) | |
490 | NEXT_INSN (XVECEXP (PATTERN (PREV_INSN (seq_insn)), 0, | |
491 | XVECLEN (PATTERN (PREV_INSN (seq_insn)), 0) - 1)) | |
492 | = seq_insn; | |
493 | ||
494 | if (NEXT_INSN (seq_insn) && GET_CODE (NEXT_INSN (seq_insn)) == INSN | |
495 | && GET_CODE (PATTERN (NEXT_INSN (seq_insn))) == SEQUENCE) | |
496 | PREV_INSN (XVECEXP (PATTERN (NEXT_INSN (seq_insn)), 0, 0)) = seq_insn; | |
497 | ||
9c7e2978 RK |
498 | /* If there used to be a BARRIER, put it back. */ |
499 | if (had_barrier) | |
500 | emit_barrier_after (seq_insn); | |
501 | ||
502 | if (i != length + 1) | |
503 | abort (); | |
504 | ||
505 | return seq_insn; | |
506 | } | |
507 | ||
508 | /* Add INSN to DELAY_LIST and return the head of the new list. The list must | |
509 | be in the order in which the insns are to be executed. */ | |
510 | ||
511 | static rtx | |
512 | add_to_delay_list (insn, delay_list) | |
513 | rtx insn; | |
514 | rtx delay_list; | |
515 | { | |
c8cfe1f6 | 516 | /* If we have an empty list, just make a new list element. If |
9ec36da5 | 517 | INSN has its block number recorded, clear it since we may |
c8cfe1f6 RK |
518 | be moving the insn to a new block. */ |
519 | ||
9c7e2978 | 520 | if (delay_list == 0) |
c8cfe1f6 | 521 | { |
ca545bb5 | 522 | clear_hashed_info_for_insn (insn); |
38a448ca | 523 | return gen_rtx_INSN_LIST (VOIDmode, insn, NULL_RTX); |
c8cfe1f6 | 524 | } |
9c7e2978 RK |
525 | |
526 | /* Otherwise this must be an INSN_LIST. Add INSN to the end of the | |
527 | list. */ | |
528 | XEXP (delay_list, 1) = add_to_delay_list (insn, XEXP (delay_list, 1)); | |
529 | ||
530 | return delay_list; | |
531 | } | |
9c7e2978 | 532 | \f |
ab87f8c8 JL |
533 | /* Delete INSN from the delay slot of the insn that it is in, which may |
534 | produce an insn with no delay slots. Return the new insn. */ | |
9c7e2978 | 535 | |
96960d10 | 536 | static rtx |
9c7e2978 RK |
537 | delete_from_delay_slot (insn) |
538 | rtx insn; | |
539 | { | |
540 | rtx trial, seq_insn, seq, prev; | |
541 | rtx delay_list = 0; | |
542 | int i; | |
543 | ||
544 | /* We first must find the insn containing the SEQUENCE with INSN in its | |
545 | delay slot. Do this by finding an insn, TRIAL, where | |
546 | PREV_INSN (NEXT_INSN (TRIAL)) != TRIAL. */ | |
547 | ||
548 | for (trial = insn; | |
549 | PREV_INSN (NEXT_INSN (trial)) == trial; | |
550 | trial = NEXT_INSN (trial)) | |
551 | ; | |
552 | ||
553 | seq_insn = PREV_INSN (NEXT_INSN (trial)); | |
554 | seq = PATTERN (seq_insn); | |
555 | ||
556 | /* Create a delay list consisting of all the insns other than the one | |
557 | we are deleting (unless we were the only one). */ | |
558 | if (XVECLEN (seq, 0) > 2) | |
559 | for (i = 1; i < XVECLEN (seq, 0); i++) | |
560 | if (XVECEXP (seq, 0, i) != insn) | |
561 | delay_list = add_to_delay_list (XVECEXP (seq, 0, i), delay_list); | |
562 | ||
563 | /* Delete the old SEQUENCE, re-emit the insn that used to have the delay | |
564 | list, and rebuild the delay list if non-empty. */ | |
565 | prev = PREV_INSN (seq_insn); | |
566 | trial = XVECEXP (seq, 0, 0); | |
567 | delete_insn (seq_insn); | |
568 | add_insn_after (trial, prev); | |
569 | ||
570 | if (GET_CODE (trial) == JUMP_INSN | |
571 | && (simplejump_p (trial) || GET_CODE (PATTERN (trial)) == RETURN)) | |
572 | emit_barrier_after (trial); | |
573 | ||
574 | /* If there are any delay insns, remit them. Otherwise clear the | |
575 | annul flag. */ | |
576 | if (delay_list) | |
91a51951 | 577 | trial = emit_delay_sequence (trial, delay_list, XVECLEN (seq, 0) - 2); |
9c7e2978 RK |
578 | else |
579 | INSN_ANNULLED_BRANCH_P (trial) = 0; | |
580 | ||
581 | INSN_FROM_TARGET_P (insn) = 0; | |
582 | ||
583 | /* Show we need to fill this insn again. */ | |
584 | obstack_ptr_grow (&unfilled_slots_obstack, trial); | |
96960d10 HB |
585 | |
586 | return trial; | |
9c7e2978 RK |
587 | } |
588 | \f | |
589 | /* Delete INSN, a JUMP_INSN. If it is a conditional jump, we must track down | |
590 | the insn that sets CC0 for it and delete it too. */ | |
591 | ||
592 | static void | |
593 | delete_scheduled_jump (insn) | |
594 | rtx insn; | |
595 | { | |
596 | /* Delete the insn that sets cc0 for us. On machines without cc0, we could | |
597 | delete the insn that sets the condition code, but it is hard to find it. | |
598 | Since this case is rare anyway, don't bother trying; there would likely | |
599 | be other insns that became dead anyway, which we wouldn't know to | |
600 | delete. */ | |
601 | ||
602 | #ifdef HAVE_cc0 | |
603 | if (reg_mentioned_p (cc0_rtx, insn)) | |
604 | { | |
fb3821f7 | 605 | rtx note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX); |
9c7e2978 RK |
606 | |
607 | /* If a reg-note was found, it points to an insn to set CC0. This | |
608 | insn is in the delay list of some other insn. So delete it from | |
609 | the delay list it was in. */ | |
610 | if (note) | |
611 | { | |
fb3821f7 | 612 | if (! FIND_REG_INC_NOTE (XEXP (note, 0), NULL_RTX) |
9c7e2978 RK |
613 | && sets_cc0_p (PATTERN (XEXP (note, 0))) == 1) |
614 | delete_from_delay_slot (XEXP (note, 0)); | |
615 | } | |
616 | else | |
617 | { | |
618 | /* The insn setting CC0 is our previous insn, but it may be in | |
619 | a delay slot. It will be the last insn in the delay slot, if | |
620 | it is. */ | |
621 | rtx trial = previous_insn (insn); | |
622 | if (GET_CODE (trial) == NOTE) | |
623 | trial = prev_nonnote_insn (trial); | |
624 | if (sets_cc0_p (PATTERN (trial)) != 1 | |
625 | || FIND_REG_INC_NOTE (trial, 0)) | |
626 | return; | |
627 | if (PREV_INSN (NEXT_INSN (trial)) == trial) | |
628 | delete_insn (trial); | |
629 | else | |
630 | delete_from_delay_slot (trial); | |
631 | } | |
632 | } | |
633 | #endif | |
634 | ||
635 | delete_insn (insn); | |
636 | } | |
637 | \f | |
638 | /* Counters for delay-slot filling. */ | |
639 | ||
640 | #define NUM_REORG_FUNCTIONS 2 | |
641 | #define MAX_DELAY_HISTOGRAM 3 | |
642 | #define MAX_REORG_PASSES 2 | |
643 | ||
644 | static int num_insns_needing_delays[NUM_REORG_FUNCTIONS][MAX_REORG_PASSES]; | |
645 | ||
646 | static int num_filled_delays[NUM_REORG_FUNCTIONS][MAX_DELAY_HISTOGRAM+1][MAX_REORG_PASSES]; | |
647 | ||
648 | static int reorg_pass_number; | |
649 | ||
650 | static void | |
651 | note_delay_statistics (slots_filled, index) | |
652 | int slots_filled, index; | |
653 | { | |
654 | num_insns_needing_delays[index][reorg_pass_number]++; | |
655 | if (slots_filled > MAX_DELAY_HISTOGRAM) | |
656 | slots_filled = MAX_DELAY_HISTOGRAM; | |
657 | num_filled_delays[index][slots_filled][reorg_pass_number]++; | |
658 | } | |
659 | \f | |
660 | #if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS) | |
661 | ||
662 | /* Optimize the following cases: | |
663 | ||
664 | 1. When a conditional branch skips over only one instruction, | |
665 | use an annulling branch and put that insn in the delay slot. | |
6dc42e49 RS |
666 | Use either a branch that annuls when the condition if true or |
667 | invert the test with a branch that annuls when the condition is | |
9c7e2978 RK |
668 | false. This saves insns, since otherwise we must copy an insn |
669 | from the L1 target. | |
670 | ||
671 | (orig) (skip) (otherwise) | |
672 | Bcc.n L1 Bcc',a L1 Bcc,a L1' | |
673 | insn insn insn2 | |
674 | L1: L1: L1: | |
675 | insn2 insn2 insn2 | |
676 | insn3 insn3 L1': | |
677 | insn3 | |
678 | ||
679 | 2. When a conditional branch skips over only one instruction, | |
680 | and after that, it unconditionally branches somewhere else, | |
681 | perform the similar optimization. This saves executing the | |
682 | second branch in the case where the inverted condition is true. | |
683 | ||
684 | Bcc.n L1 Bcc',a L2 | |
685 | insn insn | |
686 | L1: L1: | |
687 | Bra L2 Bra L2 | |
688 | ||
689 | INSN is a JUMP_INSN. | |
690 | ||
691 | This should be expanded to skip over N insns, where N is the number | |
692 | of delay slots required. */ | |
693 | ||
694 | static rtx | |
695 | optimize_skip (insn) | |
696 | register rtx insn; | |
697 | { | |
698 | register rtx trial = next_nonnote_insn (insn); | |
699 | rtx next_trial = next_active_insn (trial); | |
700 | rtx delay_list = 0; | |
701 | rtx target_label; | |
35523fce JL |
702 | int flags; |
703 | ||
704 | flags = get_jump_flags (insn, JUMP_LABEL (insn)); | |
9c7e2978 RK |
705 | |
706 | if (trial == 0 | |
707 | || GET_CODE (trial) != INSN | |
708 | || GET_CODE (PATTERN (trial)) == SEQUENCE | |
709 | || recog_memoized (trial) < 0 | |
35523fce JL |
710 | || (! eligible_for_annul_false (insn, 0, trial, flags) |
711 | && ! eligible_for_annul_true (insn, 0, trial, flags))) | |
9c7e2978 RK |
712 | return 0; |
713 | ||
714 | /* There are two cases where we are just executing one insn (we assume | |
715 | here that a branch requires only one insn; this should be generalized | |
716 | at some point): Where the branch goes around a single insn or where | |
717 | we have one insn followed by a branch to the same label we branch to. | |
718 | In both of these cases, inverting the jump and annulling the delay | |
719 | slot give the same effect in fewer insns. */ | |
720 | if ((next_trial == next_active_insn (JUMP_LABEL (insn))) | |
721 | || (next_trial != 0 | |
722 | && GET_CODE (next_trial) == JUMP_INSN | |
723 | && JUMP_LABEL (insn) == JUMP_LABEL (next_trial) | |
724 | && (simplejump_p (next_trial) | |
725 | || GET_CODE (PATTERN (next_trial)) == RETURN))) | |
726 | { | |
35523fce | 727 | if (eligible_for_annul_false (insn, 0, trial, flags)) |
9c7e2978 RK |
728 | { |
729 | if (invert_jump (insn, JUMP_LABEL (insn))) | |
730 | INSN_FROM_TARGET_P (trial) = 1; | |
35523fce | 731 | else if (! eligible_for_annul_true (insn, 0, trial, flags)) |
9c7e2978 RK |
732 | return 0; |
733 | } | |
734 | ||
fb3821f7 | 735 | delay_list = add_to_delay_list (trial, NULL_RTX); |
9c7e2978 RK |
736 | next_trial = next_active_insn (trial); |
737 | update_block (trial, trial); | |
738 | delete_insn (trial); | |
739 | ||
740 | /* Also, if we are targeting an unconditional | |
741 | branch, thread our jump to the target of that branch. Don't | |
742 | change this into a RETURN here, because it may not accept what | |
743 | we have in the delay slot. We'll fix this up later. */ | |
744 | if (next_trial && GET_CODE (next_trial) == JUMP_INSN | |
745 | && (simplejump_p (next_trial) | |
746 | || GET_CODE (PATTERN (next_trial)) == RETURN)) | |
747 | { | |
748 | target_label = JUMP_LABEL (next_trial); | |
749 | if (target_label == 0) | |
750 | target_label = find_end_label (); | |
0e5bad53 JL |
751 | |
752 | /* Recompute the flags based on TARGET_LABEL since threading | |
753 | the jump to TARGET_LABEL may change the direction of the | |
754 | jump (which may change the circumstances in which the | |
755 | delay slot is nullified). */ | |
756 | flags = get_jump_flags (insn, target_label); | |
757 | if (eligible_for_annul_true (insn, 0, trial, flags)) | |
758 | reorg_redirect_jump (insn, target_label); | |
9c7e2978 RK |
759 | } |
760 | ||
761 | INSN_ANNULLED_BRANCH_P (insn) = 1; | |
762 | } | |
763 | ||
764 | return delay_list; | |
765 | } | |
766 | #endif | |
767 | \f | |
35523fce JL |
768 | |
769 | /* Encode and return branch direction and prediction information for | |
770 | INSN assuming it will jump to LABEL. | |
771 | ||
772 | Non conditional branches return no direction information and | |
773 | are predicted as very likely taken. */ | |
0f41302f | 774 | |
35523fce JL |
775 | static int |
776 | get_jump_flags (insn, label) | |
777 | rtx insn, label; | |
778 | { | |
779 | int flags; | |
780 | ||
781 | /* get_jump_flags can be passed any insn with delay slots, these may | |
782 | be INSNs, CALL_INSNs, or JUMP_INSNs. Only JUMP_INSNs have branch | |
783 | direction information, and only if they are conditional jumps. | |
784 | ||
785 | If LABEL is zero, then there is no way to determine the branch | |
786 | direction. */ | |
787 | if (GET_CODE (insn) == JUMP_INSN | |
3480bb98 | 788 | && (condjump_p (insn) || condjump_in_parallel_p (insn)) |
35523fce | 789 | && INSN_UID (insn) <= max_uid |
e328af29 RK |
790 | && label != 0 |
791 | && INSN_UID (label) <= max_uid) | |
35523fce JL |
792 | flags |
793 | = (uid_to_ruid[INSN_UID (label)] > uid_to_ruid[INSN_UID (insn)]) | |
794 | ? ATTR_FLAG_forward : ATTR_FLAG_backward; | |
795 | /* No valid direction information. */ | |
796 | else | |
797 | flags = 0; | |
798 | ||
799 | /* If insn is a conditional branch call mostly_true_jump to get | |
800 | determine the branch prediction. | |
801 | ||
802 | Non conditional branches are predicted as very likely taken. */ | |
803 | if (GET_CODE (insn) == JUMP_INSN | |
3480bb98 | 804 | && (condjump_p (insn) || condjump_in_parallel_p (insn))) |
35523fce JL |
805 | { |
806 | int prediction; | |
807 | ||
808 | prediction = mostly_true_jump (insn, get_branch_condition (insn, label)); | |
809 | switch (prediction) | |
810 | { | |
811 | case 2: | |
812 | flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely); | |
813 | break; | |
814 | case 1: | |
815 | flags |= ATTR_FLAG_likely; | |
816 | break; | |
35523fce JL |
817 | case 0: |
818 | flags |= ATTR_FLAG_unlikely; | |
819 | break; | |
35523fce JL |
820 | case -1: |
821 | flags |= (ATTR_FLAG_very_unlikely | ATTR_FLAG_unlikely); | |
822 | break; | |
823 | ||
824 | default: | |
825 | abort(); | |
826 | } | |
827 | } | |
828 | else | |
829 | flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely); | |
830 | ||
831 | return flags; | |
832 | } | |
833 | ||
65753f55 | 834 | /* Return 1 if INSN is a destination that will be branched to rarely (the |
0275a51b RK |
835 | return point of a function); return 2 if DEST will be branched to very |
836 | rarely (a call to a function that doesn't return). Otherwise, | |
837 | return 0. */ | |
838 | ||
839 | static int | |
840 | rare_destination (insn) | |
841 | rtx insn; | |
842 | { | |
843 | int jump_count = 0; | |
65753f55 | 844 | rtx next; |
0275a51b | 845 | |
65753f55 | 846 | for (; insn; insn = next) |
0275a51b RK |
847 | { |
848 | if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == SEQUENCE) | |
849 | insn = XVECEXP (PATTERN (insn), 0, 0); | |
850 | ||
65753f55 RK |
851 | next = NEXT_INSN (insn); |
852 | ||
0275a51b RK |
853 | switch (GET_CODE (insn)) |
854 | { | |
855 | case CODE_LABEL: | |
856 | return 0; | |
857 | case BARRIER: | |
858 | /* A BARRIER can either be after a JUMP_INSN or a CALL_INSN. We | |
859 | don't scan past JUMP_INSNs, so any barrier we find here must | |
860 | have been after a CALL_INSN and hence mean the call doesn't | |
861 | return. */ | |
862 | return 2; | |
863 | case JUMP_INSN: | |
864 | if (GET_CODE (PATTERN (insn)) == RETURN) | |
865 | return 1; | |
866 | else if (simplejump_p (insn) | |
867 | && jump_count++ < 10) | |
65753f55 | 868 | next = JUMP_LABEL (insn); |
0275a51b RK |
869 | else |
870 | return 0; | |
91a51951 KG |
871 | |
872 | default: | |
873 | break; | |
0275a51b RK |
874 | } |
875 | } | |
876 | ||
877 | /* If we got here it means we hit the end of the function. So this | |
878 | is an unlikely destination. */ | |
879 | ||
880 | return 1; | |
881 | } | |
882 | ||
9c7e2978 RK |
883 | /* Return truth value of the statement that this branch |
884 | is mostly taken. If we think that the branch is extremely likely | |
885 | to be taken, we return 2. If the branch is slightly more likely to be | |
0275a51b RK |
886 | taken, return 1. If the branch is slightly less likely to be taken, |
887 | return 0 and if the branch is highly unlikely to be taken, return -1. | |
9c7e2978 RK |
888 | |
889 | CONDITION, if non-zero, is the condition that JUMP_INSN is testing. */ | |
890 | ||
891 | static int | |
892 | mostly_true_jump (jump_insn, condition) | |
893 | rtx jump_insn, condition; | |
894 | { | |
895 | rtx target_label = JUMP_LABEL (jump_insn); | |
896 | rtx insn; | |
0275a51b RK |
897 | int rare_dest = rare_destination (target_label); |
898 | int rare_fallthrough = rare_destination (NEXT_INSN (jump_insn)); | |
899 | ||
a6c383b0 DE |
900 | /* If branch probabilities are available, then use that number since it |
901 | always gives a correct answer. */ | |
902 | if (flag_branch_probabilities) | |
903 | { | |
6f4d7222 | 904 | rtx note = find_reg_note (jump_insn, REG_BR_PROB, 0); |
a6c383b0 DE |
905 | if (note) |
906 | { | |
907 | int prob = XINT (note, 0); | |
908 | ||
909 | if (prob >= REG_BR_PROB_BASE * 9 / 10) | |
910 | return 2; | |
911 | else if (prob >= REG_BR_PROB_BASE / 2) | |
912 | return 1; | |
913 | else if (prob >= REG_BR_PROB_BASE / 10) | |
914 | return 0; | |
915 | else | |
916 | return -1; | |
917 | } | |
918 | } | |
919 | ||
0275a51b RK |
920 | /* If this is a branch outside a loop, it is highly unlikely. */ |
921 | if (GET_CODE (PATTERN (jump_insn)) == SET | |
922 | && GET_CODE (SET_SRC (PATTERN (jump_insn))) == IF_THEN_ELSE | |
923 | && ((GET_CODE (XEXP (SET_SRC (PATTERN (jump_insn)), 1)) == LABEL_REF | |
924 | && LABEL_OUTSIDE_LOOP_P (XEXP (SET_SRC (PATTERN (jump_insn)), 1))) | |
925 | || (GET_CODE (XEXP (SET_SRC (PATTERN (jump_insn)), 2)) == LABEL_REF | |
926 | && LABEL_OUTSIDE_LOOP_P (XEXP (SET_SRC (PATTERN (jump_insn)), 2))))) | |
927 | return -1; | |
928 | ||
929 | if (target_label) | |
4d0e69c3 | 930 | { |
0275a51b RK |
931 | /* If this is the test of a loop, it is very likely true. We scan |
932 | backwards from the target label. If we find a NOTE_INSN_LOOP_BEG | |
933 | before the next real insn, we assume the branch is to the top of | |
934 | the loop. */ | |
935 | for (insn = PREV_INSN (target_label); | |
936 | insn && GET_CODE (insn) == NOTE; | |
937 | insn = PREV_INSN (insn)) | |
938 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) | |
939 | return 2; | |
940 | ||
941 | /* If this is a jump to the test of a loop, it is likely true. We scan | |
942 | forwards from the target label. If we find a NOTE_INSN_LOOP_VTOP | |
943 | before the next real insn, we assume the branch is to the loop branch | |
944 | test. */ | |
945 | for (insn = NEXT_INSN (target_label); | |
946 | insn && GET_CODE (insn) == NOTE; | |
947 | insn = PREV_INSN (insn)) | |
948 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP) | |
949 | return 1; | |
4d0e69c3 | 950 | } |
9c7e2978 | 951 | |
abc95ed3 | 952 | /* Look at the relative rarities of the fallthrough and destination. If |
0f41302f | 953 | they differ, we can predict the branch that way. */ |
9c7e2978 | 954 | |
0275a51b RK |
955 | switch (rare_fallthrough - rare_dest) |
956 | { | |
957 | case -2: | |
958 | return -1; | |
959 | case -1: | |
960 | return 0; | |
961 | case 0: | |
962 | break; | |
963 | case 1: | |
4d0e69c3 | 964 | return 1; |
0275a51b RK |
965 | case 2: |
966 | return 2; | |
967 | } | |
4d0e69c3 | 968 | |
9c7e2978 RK |
969 | /* If we couldn't figure out what this jump was, assume it won't be |
970 | taken. This should be rare. */ | |
971 | if (condition == 0) | |
972 | return 0; | |
973 | ||
974 | /* EQ tests are usually false and NE tests are usually true. Also, | |
975 | most quantities are positive, so we can make the appropriate guesses | |
976 | about signed comparisons against zero. */ | |
977 | switch (GET_CODE (condition)) | |
978 | { | |
979 | case CONST_INT: | |
980 | /* Unconditional branch. */ | |
981 | return 1; | |
982 | case EQ: | |
983 | return 0; | |
984 | case NE: | |
985 | return 1; | |
986 | case LE: | |
987 | case LT: | |
988 | if (XEXP (condition, 1) == const0_rtx) | |
989 | return 0; | |
990 | break; | |
991 | case GE: | |
992 | case GT: | |
993 | if (XEXP (condition, 1) == const0_rtx) | |
994 | return 1; | |
995 | break; | |
91a51951 KG |
996 | |
997 | default: | |
998 | break; | |
9c7e2978 RK |
999 | } |
1000 | ||
1001 | /* Predict backward branches usually take, forward branches usually not. If | |
1002 | we don't know whether this is forward or backward, assume the branch | |
1003 | will be taken, since most are. */ | |
13b8df74 RK |
1004 | return (target_label == 0 || INSN_UID (jump_insn) > max_uid |
1005 | || INSN_UID (target_label) > max_uid | |
9c7e2978 RK |
1006 | || (uid_to_ruid[INSN_UID (jump_insn)] |
1007 | > uid_to_ruid[INSN_UID (target_label)]));; | |
1008 | } | |
1009 | ||
1010 | /* Return the condition under which INSN will branch to TARGET. If TARGET | |
1011 | is zero, return the condition under which INSN will return. If INSN is | |
1012 | an unconditional branch, return const_true_rtx. If INSN isn't a simple | |
1013 | type of jump, or it doesn't go to TARGET, return 0. */ | |
1014 | ||
1015 | static rtx | |
1016 | get_branch_condition (insn, target) | |
1017 | rtx insn; | |
1018 | rtx target; | |
1019 | { | |
1020 | rtx pat = PATTERN (insn); | |
1021 | rtx src; | |
1022 | ||
3480bb98 JL |
1023 | if (condjump_in_parallel_p (insn)) |
1024 | pat = XVECEXP (pat, 0, 0); | |
1025 | ||
9c7e2978 RK |
1026 | if (GET_CODE (pat) == RETURN) |
1027 | return target == 0 ? const_true_rtx : 0; | |
1028 | ||
1029 | else if (GET_CODE (pat) != SET || SET_DEST (pat) != pc_rtx) | |
1030 | return 0; | |
1031 | ||
1032 | src = SET_SRC (pat); | |
1033 | if (GET_CODE (src) == LABEL_REF && XEXP (src, 0) == target) | |
1034 | return const_true_rtx; | |
1035 | ||
1036 | else if (GET_CODE (src) == IF_THEN_ELSE | |
1037 | && ((target == 0 && GET_CODE (XEXP (src, 1)) == RETURN) | |
1038 | || (GET_CODE (XEXP (src, 1)) == LABEL_REF | |
1039 | && XEXP (XEXP (src, 1), 0) == target)) | |
1040 | && XEXP (src, 2) == pc_rtx) | |
1041 | return XEXP (src, 0); | |
1042 | ||
1043 | else if (GET_CODE (src) == IF_THEN_ELSE | |
1044 | && ((target == 0 && GET_CODE (XEXP (src, 2)) == RETURN) | |
1045 | || (GET_CODE (XEXP (src, 2)) == LABEL_REF | |
1046 | && XEXP (XEXP (src, 2), 0) == target)) | |
1047 | && XEXP (src, 1) == pc_rtx) | |
38a448ca RH |
1048 | return gen_rtx_fmt_ee (reverse_condition (GET_CODE (XEXP (src, 0))), |
1049 | GET_MODE (XEXP (src, 0)), | |
1050 | XEXP (XEXP (src, 0), 0), XEXP (XEXP (src, 0), 1)); | |
58c8c593 RK |
1051 | |
1052 | return 0; | |
9c7e2978 RK |
1053 | } |
1054 | ||
1055 | /* Return non-zero if CONDITION is more strict than the condition of | |
1056 | INSN, i.e., if INSN will always branch if CONDITION is true. */ | |
1057 | ||
1058 | static int | |
1059 | condition_dominates_p (condition, insn) | |
1060 | rtx condition; | |
1061 | rtx insn; | |
1062 | { | |
1063 | rtx other_condition = get_branch_condition (insn, JUMP_LABEL (insn)); | |
1064 | enum rtx_code code = GET_CODE (condition); | |
1065 | enum rtx_code other_code; | |
1066 | ||
1067 | if (rtx_equal_p (condition, other_condition) | |
1068 | || other_condition == const_true_rtx) | |
1069 | return 1; | |
1070 | ||
1071 | else if (condition == const_true_rtx || other_condition == 0) | |
1072 | return 0; | |
1073 | ||
1074 | other_code = GET_CODE (other_condition); | |
1075 | if (GET_RTX_LENGTH (code) != 2 || GET_RTX_LENGTH (other_code) != 2 | |
1076 | || ! rtx_equal_p (XEXP (condition, 0), XEXP (other_condition, 0)) | |
1077 | || ! rtx_equal_p (XEXP (condition, 1), XEXP (other_condition, 1))) | |
1078 | return 0; | |
1079 | ||
1080 | return comparison_dominates_p (code, other_code); | |
1081 | } | |
83fd5651 JL |
1082 | |
1083 | /* Return non-zero if redirecting JUMP to NEWLABEL does not invalidate | |
1084 | any insns already in the delay slot of JUMP. */ | |
1085 | ||
1086 | static int | |
1087 | redirect_with_delay_slots_safe_p (jump, newlabel, seq) | |
1088 | rtx jump, newlabel, seq; | |
1089 | { | |
91a51951 | 1090 | int flags, i; |
83fd5651 JL |
1091 | rtx pat = PATTERN (seq); |
1092 | ||
1093 | /* Make sure all the delay slots of this jump would still | |
1094 | be valid after threading the jump. If they are still | |
1095 | valid, then return non-zero. */ | |
1096 | ||
1097 | flags = get_jump_flags (jump, newlabel); | |
1098 | for (i = 1; i < XVECLEN (pat, 0); i++) | |
1099 | if (! ( | |
1100 | #ifdef ANNUL_IFFALSE_SLOTS | |
1101 | (INSN_ANNULLED_BRANCH_P (jump) | |
1102 | && INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) | |
1103 | ? eligible_for_annul_false (jump, i - 1, | |
1104 | XVECEXP (pat, 0, i), flags) : | |
1105 | #endif | |
1106 | #ifdef ANNUL_IFTRUE_SLOTS | |
1107 | (INSN_ANNULLED_BRANCH_P (jump) | |
1108 | && ! INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) | |
1109 | ? eligible_for_annul_true (jump, i - 1, | |
1110 | XVECEXP (pat, 0, i), flags) : | |
1111 | #endif | |
1112 | eligible_for_delay (jump, i -1, XVECEXP (pat, 0, i), flags))) | |
1113 | break; | |
1114 | ||
1115 | return (i == XVECLEN (pat, 0)); | |
1116 | } | |
1117 | ||
b304ad47 JL |
1118 | /* Return non-zero if redirecting JUMP to NEWLABEL does not invalidate |
1119 | any insns we wish to place in the delay slot of JUMP. */ | |
1120 | ||
1121 | static int | |
1122 | redirect_with_delay_list_safe_p (jump, newlabel, delay_list) | |
1123 | rtx jump, newlabel, delay_list; | |
1124 | { | |
1125 | int flags, i; | |
1126 | rtx li; | |
1127 | ||
1128 | /* Make sure all the insns in DELAY_LIST would still be | |
1129 | valid after threading the jump. If they are still | |
1130 | valid, then return non-zero. */ | |
1131 | ||
1132 | flags = get_jump_flags (jump, newlabel); | |
1133 | for (li = delay_list, i = 0; li; li = XEXP (li, 1), i++) | |
1134 | if (! ( | |
1135 | #ifdef ANNUL_IFFALSE_SLOTS | |
1136 | (INSN_ANNULLED_BRANCH_P (jump) | |
1137 | && INSN_FROM_TARGET_P (XEXP (li, 0))) | |
4791d99b | 1138 | ? eligible_for_annul_false (jump, i, XEXP (li, 0), flags) : |
b304ad47 JL |
1139 | #endif |
1140 | #ifdef ANNUL_IFTRUE_SLOTS | |
1141 | (INSN_ANNULLED_BRANCH_P (jump) | |
1142 | && ! INSN_FROM_TARGET_P (XEXP (li, 0))) | |
4791d99b | 1143 | ? eligible_for_annul_true (jump, i, XEXP (li, 0), flags) : |
b304ad47 | 1144 | #endif |
4791d99b | 1145 | eligible_for_delay (jump, i, XEXP (li, 0), flags))) |
b304ad47 JL |
1146 | break; |
1147 | ||
1148 | return (li == NULL); | |
1149 | } | |
1150 | ||
96960d10 HB |
1151 | /* DELAY_LIST is a list of insns that have already been placed into delay |
1152 | slots. See if all of them have the same annulling status as ANNUL_TRUE_P. | |
1153 | If not, return 0; otherwise return 1. */ | |
1154 | ||
1155 | static int | |
1156 | check_annul_list_true_false (annul_true_p, delay_list) | |
1157 | int annul_true_p; | |
1158 | rtx delay_list; | |
1159 | { | |
f0c76b51 | 1160 | rtx temp; |
96960d10 HB |
1161 | |
1162 | if (delay_list) | |
1163 | { | |
1164 | for (temp = delay_list; temp; temp = XEXP (temp, 1)) | |
1165 | { | |
1166 | rtx trial = XEXP (temp, 0); | |
1167 | ||
1168 | if ((annul_true_p && INSN_FROM_TARGET_P (trial)) | |
1169 | || (!annul_true_p && !INSN_FROM_TARGET_P (trial))) | |
1170 | return 0; | |
1171 | } | |
1172 | } | |
ab87f8c8 | 1173 | |
96960d10 HB |
1174 | return 1; |
1175 | } | |
1176 | ||
9c7e2978 RK |
1177 | \f |
1178 | /* INSN branches to an insn whose pattern SEQ is a SEQUENCE. Given that | |
1179 | the condition tested by INSN is CONDITION and the resources shown in | |
1180 | OTHER_NEEDED are needed after INSN, see whether INSN can take all the insns | |
1181 | from SEQ's delay list, in addition to whatever insns it may execute | |
1182 | (in DELAY_LIST). SETS and NEEDED are denote resources already set and | |
1183 | needed while searching for delay slot insns. Return the concatenated | |
1184 | delay list if possible, otherwise, return 0. | |
1185 | ||
1186 | SLOTS_TO_FILL is the total number of slots required by INSN, and | |
1187 | PSLOTS_FILLED points to the number filled so far (also the number of | |
1188 | insns in DELAY_LIST). It is updated with the number that have been | |
1189 | filled from the SEQUENCE, if any. | |
1190 | ||
1191 | PANNUL_P points to a non-zero value if we already know that we need | |
1192 | to annul INSN. If this routine determines that annulling is needed, | |
1193 | it may set that value non-zero. | |
1194 | ||
1195 | PNEW_THREAD points to a location that is to receive the place at which | |
1196 | execution should continue. */ | |
1197 | ||
1198 | static rtx | |
1199 | steal_delay_list_from_target (insn, condition, seq, delay_list, | |
1200 | sets, needed, other_needed, | |
1201 | slots_to_fill, pslots_filled, pannul_p, | |
1202 | pnew_thread) | |
1203 | rtx insn, condition; | |
1204 | rtx seq; | |
1205 | rtx delay_list; | |
1206 | struct resources *sets, *needed, *other_needed; | |
1207 | int slots_to_fill; | |
1208 | int *pslots_filled; | |
1209 | int *pannul_p; | |
1210 | rtx *pnew_thread; | |
1211 | { | |
1212 | rtx temp; | |
1213 | int slots_remaining = slots_to_fill - *pslots_filled; | |
1214 | int total_slots_filled = *pslots_filled; | |
1215 | rtx new_delay_list = 0; | |
1216 | int must_annul = *pannul_p; | |
f0c76b51 | 1217 | int used_annul = 0; |
ab87f8c8 | 1218 | int i; |
18e765cb | 1219 | struct resources cc_set; |
9c7e2978 RK |
1220 | |
1221 | /* We can't do anything if there are more delay slots in SEQ than we | |
1222 | can handle, or if we don't know that it will be a taken branch. | |
9c7e2978 | 1223 | We know that it will be a taken branch if it is either an unconditional |
fe41a98e JW |
1224 | branch or a conditional branch with a stricter branch condition. |
1225 | ||
1226 | Also, exit if the branch has more than one set, since then it is computing | |
1227 | other results that can't be ignored, e.g. the HPPA mov&branch instruction. | |
1228 | ??? It may be possible to move other sets into INSN in addition to | |
18e765cb JL |
1229 | moving the instructions in the delay slots. |
1230 | ||
1231 | We can not steal the delay list if one of the instructions in the | |
1232 | current delay_list modifies the condition codes and the jump in the | |
1233 | sequence is a conditional jump. We can not do this because we can | |
1234 | not change the direction of the jump because the condition codes | |
1235 | will effect the direction of the jump in the sequence. */ | |
1236 | ||
1237 | CLEAR_RESOURCE (&cc_set); | |
1238 | for (temp = delay_list; temp; temp = XEXP (temp, 1)) | |
1239 | { | |
1240 | rtx trial = XEXP (temp, 0); | |
1241 | ||
1242 | mark_set_resources (trial, &cc_set, 0, 1); | |
1243 | if (insn_references_resource_p (XVECEXP (seq , 0, 0), &cc_set, 0)) | |
1244 | return delay_list; | |
1245 | } | |
9c7e2978 RK |
1246 | |
1247 | if (XVECLEN (seq, 0) - 1 > slots_remaining | |
fe41a98e JW |
1248 | || ! condition_dominates_p (condition, XVECEXP (seq, 0, 0)) |
1249 | || ! single_set (XVECEXP (seq, 0, 0))) | |
9c7e2978 RK |
1250 | return delay_list; |
1251 | ||
1252 | for (i = 1; i < XVECLEN (seq, 0); i++) | |
1253 | { | |
1254 | rtx trial = XVECEXP (seq, 0, i); | |
35523fce | 1255 | int flags; |
9c7e2978 RK |
1256 | |
1257 | if (insn_references_resource_p (trial, sets, 0) | |
1258 | || insn_sets_resource_p (trial, needed, 0) | |
1259 | || insn_sets_resource_p (trial, sets, 0) | |
1260 | #ifdef HAVE_cc0 | |
1261 | /* If TRIAL sets CC0, we can't copy it, so we can't steal this | |
1262 | delay list. */ | |
fb3821f7 | 1263 | || find_reg_note (trial, REG_CC_USER, NULL_RTX) |
9c7e2978 RK |
1264 | #endif |
1265 | /* If TRIAL is from the fallthrough code of an annulled branch insn | |
1266 | in SEQ, we cannot use it. */ | |
1267 | || (INSN_ANNULLED_BRANCH_P (XVECEXP (seq, 0, 0)) | |
1268 | && ! INSN_FROM_TARGET_P (trial))) | |
1269 | return delay_list; | |
1270 | ||
1271 | /* If this insn was already done (usually in a previous delay slot), | |
1272 | pretend we put it in our delay slot. */ | |
f898abd7 | 1273 | if (redundant_insn (trial, insn, new_delay_list)) |
9c7e2978 RK |
1274 | continue; |
1275 | ||
35523fce JL |
1276 | /* We will end up re-vectoring this branch, so compute flags |
1277 | based on jumping to the new label. */ | |
1278 | flags = get_jump_flags (insn, JUMP_LABEL (XVECEXP (seq, 0, 0))); | |
1279 | ||
9c7e2978 RK |
1280 | if (! must_annul |
1281 | && ((condition == const_true_rtx | |
1282 | || (! insn_sets_resource_p (trial, other_needed, 0) | |
1283 | && ! may_trap_p (PATTERN (trial))))) | |
35523fce | 1284 | ? eligible_for_delay (insn, total_slots_filled, trial, flags) |
96960d10 HB |
1285 | : (must_annul || (delay_list == NULL && new_delay_list == NULL)) |
1286 | && (must_annul = 1, | |
1287 | check_annul_list_true_false (0, delay_list) | |
1288 | && check_annul_list_true_false (0, new_delay_list) | |
1289 | && eligible_for_annul_false (insn, total_slots_filled, | |
1290 | trial, flags))) | |
9c7e2978 | 1291 | { |
96960d10 HB |
1292 | if (must_annul) |
1293 | used_annul = 1; | |
9c7e2978 RK |
1294 | temp = copy_rtx (trial); |
1295 | INSN_FROM_TARGET_P (temp) = 1; | |
1296 | new_delay_list = add_to_delay_list (temp, new_delay_list); | |
1297 | total_slots_filled++; | |
1298 | ||
1299 | if (--slots_remaining == 0) | |
1300 | break; | |
1301 | } | |
1302 | else | |
1303 | return delay_list; | |
1304 | } | |
1305 | ||
1306 | /* Show the place to which we will be branching. */ | |
1307 | *pnew_thread = next_active_insn (JUMP_LABEL (XVECEXP (seq, 0, 0))); | |
1308 | ||
1309 | /* Add any new insns to the delay list and update the count of the | |
1310 | number of slots filled. */ | |
1311 | *pslots_filled = total_slots_filled; | |
96960d10 HB |
1312 | if (used_annul) |
1313 | *pannul_p = 1; | |
9c7e2978 RK |
1314 | |
1315 | if (delay_list == 0) | |
1316 | return new_delay_list; | |
1317 | ||
1318 | for (temp = new_delay_list; temp; temp = XEXP (temp, 1)) | |
1319 | delay_list = add_to_delay_list (XEXP (temp, 0), delay_list); | |
1320 | ||
1321 | return delay_list; | |
1322 | } | |
1323 | \f | |
1324 | /* Similar to steal_delay_list_from_target except that SEQ is on the | |
1325 | fallthrough path of INSN. Here we only do something if the delay insn | |
1326 | of SEQ is an unconditional branch. In that case we steal its delay slot | |
1327 | for INSN since unconditional branches are much easier to fill. */ | |
1328 | ||
1329 | static rtx | |
1330 | steal_delay_list_from_fallthrough (insn, condition, seq, | |
1331 | delay_list, sets, needed, other_needed, | |
1332 | slots_to_fill, pslots_filled, pannul_p) | |
1333 | rtx insn, condition; | |
1334 | rtx seq; | |
1335 | rtx delay_list; | |
1336 | struct resources *sets, *needed, *other_needed; | |
1337 | int slots_to_fill; | |
1338 | int *pslots_filled; | |
1339 | int *pannul_p; | |
1340 | { | |
1341 | int i; | |
35523fce | 1342 | int flags; |
96960d10 HB |
1343 | int must_annul = *pannul_p; |
1344 | int used_annul = 0; | |
35523fce JL |
1345 | |
1346 | flags = get_jump_flags (insn, JUMP_LABEL (insn)); | |
9c7e2978 RK |
1347 | |
1348 | /* We can't do anything if SEQ's delay insn isn't an | |
1349 | unconditional branch. */ | |
1350 | ||
1351 | if (! simplejump_p (XVECEXP (seq, 0, 0)) | |
1352 | && GET_CODE (PATTERN (XVECEXP (seq, 0, 0))) != RETURN) | |
1353 | return delay_list; | |
1354 | ||
1355 | for (i = 1; i < XVECLEN (seq, 0); i++) | |
1356 | { | |
1357 | rtx trial = XVECEXP (seq, 0, i); | |
1358 | ||
1359 | /* If TRIAL sets CC0, stealing it will move it too far from the use | |
1360 | of CC0. */ | |
1361 | if (insn_references_resource_p (trial, sets, 0) | |
1362 | || insn_sets_resource_p (trial, needed, 0) | |
1363 | || insn_sets_resource_p (trial, sets, 0) | |
1364 | #ifdef HAVE_cc0 | |
1365 | || sets_cc0_p (PATTERN (trial)) | |
1366 | #endif | |
1367 | ) | |
1368 | ||
1369 | break; | |
1370 | ||
1371 | /* If this insn was already done, we don't need it. */ | |
f898abd7 | 1372 | if (redundant_insn (trial, insn, delay_list)) |
9c7e2978 RK |
1373 | { |
1374 | delete_from_delay_slot (trial); | |
1375 | continue; | |
1376 | } | |
1377 | ||
96960d10 | 1378 | if (! must_annul |
9c7e2978 RK |
1379 | && ((condition == const_true_rtx |
1380 | || (! insn_sets_resource_p (trial, other_needed, 0) | |
1381 | && ! may_trap_p (PATTERN (trial))))) | |
35523fce | 1382 | ? eligible_for_delay (insn, *pslots_filled, trial, flags) |
96960d10 HB |
1383 | : (must_annul || delay_list == NULL) && (must_annul = 1, |
1384 | check_annul_list_true_false (1, delay_list) | |
1385 | && eligible_for_annul_true (insn, *pslots_filled, trial, flags))) | |
9c7e2978 | 1386 | { |
96960d10 HB |
1387 | if (must_annul) |
1388 | used_annul = 1; | |
9c7e2978 RK |
1389 | delete_from_delay_slot (trial); |
1390 | delay_list = add_to_delay_list (trial, delay_list); | |
1391 | ||
1392 | if (++(*pslots_filled) == slots_to_fill) | |
1393 | break; | |
1394 | } | |
1395 | else | |
1396 | break; | |
1397 | } | |
1398 | ||
96960d10 HB |
1399 | if (used_annul) |
1400 | *pannul_p = 1; | |
9c7e2978 RK |
1401 | return delay_list; |
1402 | } | |
96960d10 | 1403 | |
9c7e2978 RK |
1404 | \f |
1405 | /* Try merging insns starting at THREAD which match exactly the insns in | |
1406 | INSN's delay list. | |
1407 | ||
1408 | If all insns were matched and the insn was previously annulling, the | |
1409 | annul bit will be cleared. | |
1410 | ||
1411 | For each insn that is merged, if the branch is or will be non-annulling, | |
1412 | we delete the merged insn. */ | |
1413 | ||
1414 | static void | |
1415 | try_merge_delay_insns (insn, thread) | |
1416 | rtx insn, thread; | |
1417 | { | |
1418 | rtx trial, next_trial; | |
1419 | rtx delay_insn = XVECEXP (PATTERN (insn), 0, 0); | |
1420 | int annul_p = INSN_ANNULLED_BRANCH_P (delay_insn); | |
1421 | int slot_number = 1; | |
1422 | int num_slots = XVECLEN (PATTERN (insn), 0); | |
1423 | rtx next_to_match = XVECEXP (PATTERN (insn), 0, slot_number); | |
1424 | struct resources set, needed; | |
1425 | rtx merged_insns = 0; | |
1426 | int i; | |
35523fce JL |
1427 | int flags; |
1428 | ||
a2f54138 | 1429 | flags = get_jump_flags (delay_insn, JUMP_LABEL (delay_insn)); |
9c7e2978 RK |
1430 | |
1431 | CLEAR_RESOURCE (&needed); | |
1432 | CLEAR_RESOURCE (&set); | |
1433 | ||
1434 | /* If this is not an annulling branch, take into account anything needed in | |
96960d10 | 1435 | INSN's delay slot. This prevents two increments from being incorrectly |
9c7e2978 RK |
1436 | folded into one. If we are annulling, this would be the correct |
1437 | thing to do. (The alternative, looking at things set in NEXT_TO_MATCH | |
1438 | will essentially disable this optimization. This method is somewhat of | |
1439 | a kludge, but I don't see a better way.) */ | |
1440 | if (! annul_p) | |
96960d10 HB |
1441 | for (i = 1 ; i < num_slots ; i++) |
1442 | if (XVECEXP (PATTERN (insn), 0, i)) | |
1443 | mark_referenced_resources (XVECEXP (PATTERN (insn), 0, i), &needed, 1); | |
9c7e2978 RK |
1444 | |
1445 | for (trial = thread; !stop_search_p (trial, 1); trial = next_trial) | |
1446 | { | |
1447 | rtx pat = PATTERN (trial); | |
ce15adaa | 1448 | rtx oldtrial = trial; |
9c7e2978 RK |
1449 | |
1450 | next_trial = next_nonnote_insn (trial); | |
1451 | ||
1452 | /* TRIAL must be a CALL_INSN or INSN. Skip USE and CLOBBER. */ | |
1453 | if (GET_CODE (trial) == INSN | |
1454 | && (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)) | |
1455 | continue; | |
1456 | ||
1457 | if (GET_CODE (next_to_match) == GET_CODE (trial) | |
1458 | #ifdef HAVE_cc0 | |
1459 | /* We can't share an insn that sets cc0. */ | |
1460 | && ! sets_cc0_p (pat) | |
1461 | #endif | |
1462 | && ! insn_references_resource_p (trial, &set, 1) | |
1463 | && ! insn_sets_resource_p (trial, &set, 1) | |
1464 | && ! insn_sets_resource_p (trial, &needed, 1) | |
1465 | && (trial = try_split (pat, trial, 0)) != 0 | |
9772d94f JW |
1466 | /* Update next_trial, in case try_split succeeded. */ |
1467 | && (next_trial = next_nonnote_insn (trial)) | |
ce15adaa RK |
1468 | /* Likewise THREAD. */ |
1469 | && (thread = oldtrial == thread ? trial : thread) | |
9c7e2978 RK |
1470 | && rtx_equal_p (PATTERN (next_to_match), PATTERN (trial)) |
1471 | /* Have to test this condition if annul condition is different | |
1472 | from (and less restrictive than) non-annulling one. */ | |
35523fce | 1473 | && eligible_for_delay (delay_insn, slot_number - 1, trial, flags)) |
9c7e2978 | 1474 | { |
9c7e2978 RK |
1475 | |
1476 | if (! annul_p) | |
1477 | { | |
f1f9081a | 1478 | update_block (trial, thread); |
8ad4abfc RK |
1479 | if (trial == thread) |
1480 | thread = next_active_insn (thread); | |
1481 | ||
9c7e2978 RK |
1482 | delete_insn (trial); |
1483 | INSN_FROM_TARGET_P (next_to_match) = 0; | |
1484 | } | |
1485 | else | |
38a448ca | 1486 | merged_insns = gen_rtx_INSN_LIST (VOIDmode, trial, merged_insns); |
9c7e2978 RK |
1487 | |
1488 | if (++slot_number == num_slots) | |
1489 | break; | |
1490 | ||
1491 | next_to_match = XVECEXP (PATTERN (insn), 0, slot_number); | |
9c7e2978 RK |
1492 | } |
1493 | ||
26d970a5 | 1494 | mark_set_resources (trial, &set, 0, 1); |
9c7e2978 RK |
1495 | mark_referenced_resources (trial, &needed, 1); |
1496 | } | |
1497 | ||
1498 | /* See if we stopped on a filled insn. If we did, try to see if its | |
1499 | delay slots match. */ | |
1500 | if (slot_number != num_slots | |
1501 | && trial && GET_CODE (trial) == INSN | |
1502 | && GET_CODE (PATTERN (trial)) == SEQUENCE | |
1503 | && ! INSN_ANNULLED_BRANCH_P (XVECEXP (PATTERN (trial), 0, 0))) | |
1504 | { | |
1505 | rtx pat = PATTERN (trial); | |
058acefd JW |
1506 | rtx filled_insn = XVECEXP (pat, 0, 0); |
1507 | ||
1508 | /* Account for resources set/needed by the filled insn. */ | |
1509 | mark_set_resources (filled_insn, &set, 0, 1); | |
1510 | mark_referenced_resources (filled_insn, &needed, 1); | |
9c7e2978 RK |
1511 | |
1512 | for (i = 1; i < XVECLEN (pat, 0); i++) | |
1513 | { | |
1514 | rtx dtrial = XVECEXP (pat, 0, i); | |
1515 | ||
1516 | if (! insn_references_resource_p (dtrial, &set, 1) | |
1517 | && ! insn_sets_resource_p (dtrial, &set, 1) | |
1518 | && ! insn_sets_resource_p (dtrial, &needed, 1) | |
1519 | #ifdef HAVE_cc0 | |
1520 | && ! sets_cc0_p (PATTERN (dtrial)) | |
1521 | #endif | |
1522 | && rtx_equal_p (PATTERN (next_to_match), PATTERN (dtrial)) | |
35523fce | 1523 | && eligible_for_delay (delay_insn, slot_number - 1, dtrial, flags)) |
9c7e2978 RK |
1524 | { |
1525 | if (! annul_p) | |
1526 | { | |
96960d10 HB |
1527 | rtx new; |
1528 | ||
f1f9081a | 1529 | update_block (dtrial, thread); |
96960d10 HB |
1530 | new = delete_from_delay_slot (dtrial); |
1531 | if (INSN_DELETED_P (thread)) | |
1532 | thread = new; | |
9c7e2978 RK |
1533 | INSN_FROM_TARGET_P (next_to_match) = 0; |
1534 | } | |
1535 | else | |
38a448ca RH |
1536 | merged_insns = gen_rtx_INSN_LIST (SImode, dtrial, |
1537 | merged_insns); | |
9c7e2978 RK |
1538 | |
1539 | if (++slot_number == num_slots) | |
1540 | break; | |
1541 | ||
1542 | next_to_match = XVECEXP (PATTERN (insn), 0, slot_number); | |
1543 | } | |
96960d10 HB |
1544 | else |
1545 | { | |
f0c76b51 JL |
1546 | /* Keep track of the set/referenced resources for the delay |
1547 | slots of any trial insns we encounter. */ | |
96960d10 HB |
1548 | mark_set_resources (dtrial, &set, 0, 1); |
1549 | mark_referenced_resources (dtrial, &needed, 1); | |
1550 | } | |
9c7e2978 RK |
1551 | } |
1552 | } | |
1553 | ||
1554 | /* If all insns in the delay slot have been matched and we were previously | |
1555 | annulling the branch, we need not any more. In that case delete all the | |
38e01259 | 1556 | merged insns. Also clear the INSN_FROM_TARGET_P bit of each insn in |
9c7e2978 RK |
1557 | the delay list so that we know that it isn't only being used at the |
1558 | target. */ | |
d58b6986 | 1559 | if (slot_number == num_slots && annul_p) |
9c7e2978 RK |
1560 | { |
1561 | for (; merged_insns; merged_insns = XEXP (merged_insns, 1)) | |
1562 | { | |
1563 | if (GET_MODE (merged_insns) == SImode) | |
1564 | { | |
96960d10 HB |
1565 | rtx new; |
1566 | ||
f1f9081a | 1567 | update_block (XEXP (merged_insns, 0), thread); |
96960d10 HB |
1568 | new = delete_from_delay_slot (XEXP (merged_insns, 0)); |
1569 | if (INSN_DELETED_P (thread)) | |
1570 | thread = new; | |
9c7e2978 RK |
1571 | } |
1572 | else | |
1573 | { | |
f1f9081a | 1574 | update_block (XEXP (merged_insns, 0), thread); |
9c7e2978 RK |
1575 | delete_insn (XEXP (merged_insns, 0)); |
1576 | } | |
1577 | } | |
1578 | ||
1579 | INSN_ANNULLED_BRANCH_P (delay_insn) = 0; | |
1580 | ||
1581 | for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++) | |
1582 | INSN_FROM_TARGET_P (XVECEXP (PATTERN (insn), 0, i)) = 0; | |
1583 | } | |
1584 | } | |
1585 | \f | |
1586 | /* See if INSN is redundant with an insn in front of TARGET. Often this | |
1587 | is called when INSN is a candidate for a delay slot of TARGET. | |
1588 | DELAY_LIST are insns that will be placed in delay slots of TARGET in front | |
1589 | of INSN. Often INSN will be redundant with an insn in a delay slot of | |
1590 | some previous insn. This happens when we have a series of branches to the | |
1591 | same label; in that case the first insn at the target might want to go | |
1592 | into each of the delay slots. | |
1593 | ||
1594 | If we are not careful, this routine can take up a significant fraction | |
1595 | of the total compilation time (4%), but only wins rarely. Hence we | |
1596 | speed this routine up by making two passes. The first pass goes back | |
1597 | until it hits a label and sees if it find an insn with an identical | |
1598 | pattern. Only in this (relatively rare) event does it check for | |
1599 | data conflicts. | |
1600 | ||
1601 | We do not split insns we encounter. This could cause us not to find a | |
1602 | redundant insn, but the cost of splitting seems greater than the possible | |
1603 | gain in rare cases. */ | |
1604 | ||
5317d2f8 | 1605 | static rtx |
f898abd7 | 1606 | redundant_insn (insn, target, delay_list) |
9c7e2978 RK |
1607 | rtx insn; |
1608 | rtx target; | |
1609 | rtx delay_list; | |
1610 | { | |
1611 | rtx target_main = target; | |
1612 | rtx ipat = PATTERN (insn); | |
1613 | rtx trial, pat; | |
1614 | struct resources needed, set; | |
1615 | int i; | |
1616 | ||
cbae24bc RK |
1617 | /* If INSN has any REG_UNUSED notes, it can't match anything since we |
1618 | are allowed to not actually assign to such a register. */ | |
1619 | if (find_reg_note (insn, REG_UNUSED, NULL_RTX) != 0) | |
1620 | return 0; | |
1621 | ||
9c7e2978 RK |
1622 | /* Scan backwards looking for a match. */ |
1623 | for (trial = PREV_INSN (target); trial; trial = PREV_INSN (trial)) | |
1624 | { | |
1625 | if (GET_CODE (trial) == CODE_LABEL) | |
1626 | return 0; | |
1627 | ||
009f6146 | 1628 | if (GET_RTX_CLASS (GET_CODE (trial)) != 'i') |
9c7e2978 RK |
1629 | continue; |
1630 | ||
1631 | pat = PATTERN (trial); | |
1632 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
1633 | continue; | |
1634 | ||
1635 | if (GET_CODE (pat) == SEQUENCE) | |
1636 | { | |
ca104c13 JL |
1637 | /* Stop for a CALL and its delay slots because it is difficult to |
1638 | track its resource needs correctly. */ | |
9c7e2978 RK |
1639 | if (GET_CODE (XVECEXP (pat, 0, 0)) == CALL_INSN) |
1640 | return 0; | |
1641 | ||
ca104c13 JL |
1642 | /* Stop for an INSN or JUMP_INSN with delayed effects and its delay |
1643 | slots because it is difficult to track its resource needs | |
1644 | correctly. */ | |
1645 | ||
1646 | #ifdef INSN_SETS_ARE_DELAYED | |
1647 | if (INSN_SETS_ARE_DELAYED (XVECEXP (pat, 0, 0))) | |
1648 | return 0; | |
1649 | #endif | |
1650 | ||
1651 | #ifdef INSN_REFERENCES_ARE_DELAYED | |
1652 | if (INSN_REFERENCES_ARE_DELAYED (XVECEXP (pat, 0, 0))) | |
1653 | return 0; | |
1654 | #endif | |
1655 | ||
1656 | /* See if any of the insns in the delay slot match, updating | |
1657 | resource requirements as we go. */ | |
9c7e2978 RK |
1658 | for (i = XVECLEN (pat, 0) - 1; i > 0; i--) |
1659 | if (GET_CODE (XVECEXP (pat, 0, i)) == GET_CODE (insn) | |
cbae24bc RK |
1660 | && rtx_equal_p (PATTERN (XVECEXP (pat, 0, i)), ipat) |
1661 | && ! find_reg_note (XVECEXP (pat, 0, i), REG_UNUSED, NULL_RTX)) | |
9c7e2978 RK |
1662 | break; |
1663 | ||
1664 | /* If found a match, exit this loop early. */ | |
1665 | if (i > 0) | |
1666 | break; | |
1667 | } | |
1668 | ||
cbae24bc RK |
1669 | else if (GET_CODE (trial) == GET_CODE (insn) && rtx_equal_p (pat, ipat) |
1670 | && ! find_reg_note (trial, REG_UNUSED, NULL_RTX)) | |
9c7e2978 RK |
1671 | break; |
1672 | } | |
1673 | ||
1674 | /* If we didn't find an insn that matches, return 0. */ | |
1675 | if (trial == 0) | |
1676 | return 0; | |
1677 | ||
1678 | /* See what resources this insn sets and needs. If they overlap, or | |
1679 | if this insn references CC0, it can't be redundant. */ | |
1680 | ||
1681 | CLEAR_RESOURCE (&needed); | |
1682 | CLEAR_RESOURCE (&set); | |
26d970a5 | 1683 | mark_set_resources (insn, &set, 0, 1); |
9c7e2978 RK |
1684 | mark_referenced_resources (insn, &needed, 1); |
1685 | ||
1686 | /* If TARGET is a SEQUENCE, get the main insn. */ | |
1687 | if (GET_CODE (target) == INSN && GET_CODE (PATTERN (target)) == SEQUENCE) | |
1688 | target_main = XVECEXP (PATTERN (target), 0, 0); | |
1689 | ||
1690 | if (resource_conflicts_p (&needed, &set) | |
1691 | #ifdef HAVE_cc0 | |
1692 | || reg_mentioned_p (cc0_rtx, ipat) | |
1693 | #endif | |
1694 | /* The insn requiring the delay may not set anything needed or set by | |
1695 | INSN. */ | |
1696 | || insn_sets_resource_p (target_main, &needed, 1) | |
1697 | || insn_sets_resource_p (target_main, &set, 1)) | |
1698 | return 0; | |
1699 | ||
1700 | /* Insns we pass may not set either NEEDED or SET, so merge them for | |
1701 | simpler tests. */ | |
1702 | needed.memory |= set.memory; | |
8eae5ed6 | 1703 | needed.unch_memory |= set.unch_memory; |
9c7e2978 RK |
1704 | IOR_HARD_REG_SET (needed.regs, set.regs); |
1705 | ||
1706 | /* This insn isn't redundant if it conflicts with an insn that either is | |
1707 | or will be in a delay slot of TARGET. */ | |
1708 | ||
1709 | while (delay_list) | |
1710 | { | |
1711 | if (insn_sets_resource_p (XEXP (delay_list, 0), &needed, 1)) | |
1712 | return 0; | |
1713 | delay_list = XEXP (delay_list, 1); | |
1714 | } | |
1715 | ||
1716 | if (GET_CODE (target) == INSN && GET_CODE (PATTERN (target)) == SEQUENCE) | |
1717 | for (i = 1; i < XVECLEN (PATTERN (target), 0); i++) | |
1718 | if (insn_sets_resource_p (XVECEXP (PATTERN (target), 0, i), &needed, 1)) | |
1719 | return 0; | |
1720 | ||
1721 | /* Scan backwards until we reach a label or an insn that uses something | |
1722 | INSN sets or sets something insn uses or sets. */ | |
1723 | ||
1724 | for (trial = PREV_INSN (target); | |
1725 | trial && GET_CODE (trial) != CODE_LABEL; | |
1726 | trial = PREV_INSN (trial)) | |
1727 | { | |
1728 | if (GET_CODE (trial) != INSN && GET_CODE (trial) != CALL_INSN | |
1729 | && GET_CODE (trial) != JUMP_INSN) | |
1730 | continue; | |
1731 | ||
1732 | pat = PATTERN (trial); | |
1733 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
1734 | continue; | |
1735 | ||
1736 | if (GET_CODE (pat) == SEQUENCE) | |
1737 | { | |
1738 | /* If this is a CALL_INSN and its delay slots, it is hard to track | |
1739 | the resource needs properly, so give up. */ | |
1740 | if (GET_CODE (XVECEXP (pat, 0, 0)) == CALL_INSN) | |
1741 | return 0; | |
1742 | ||
38e01259 | 1743 | /* If this is an INSN or JUMP_INSN with delayed effects, it |
ca104c13 JL |
1744 | is hard to track the resource needs properly, so give up. */ |
1745 | ||
1746 | #ifdef INSN_SETS_ARE_DELAYED | |
1747 | if (INSN_SETS_ARE_DELAYED (XVECEXP (pat, 0, 0))) | |
1748 | return 0; | |
1749 | #endif | |
1750 | ||
1751 | #ifdef INSN_REFERENCES_ARE_DELAYED | |
1752 | if (INSN_REFERENCES_ARE_DELAYED (XVECEXP (pat, 0, 0))) | |
1753 | return 0; | |
1754 | #endif | |
1755 | ||
9c7e2978 RK |
1756 | /* See if any of the insns in the delay slot match, updating |
1757 | resource requirements as we go. */ | |
1758 | for (i = XVECLEN (pat, 0) - 1; i > 0; i--) | |
1759 | { | |
1760 | rtx candidate = XVECEXP (pat, 0, i); | |
1761 | ||
1762 | /* If an insn will be annulled if the branch is false, it isn't | |
1763 | considered as a possible duplicate insn. */ | |
1764 | if (rtx_equal_p (PATTERN (candidate), ipat) | |
1765 | && ! (INSN_ANNULLED_BRANCH_P (XVECEXP (pat, 0, 0)) | |
1766 | && INSN_FROM_TARGET_P (candidate))) | |
1767 | { | |
1768 | /* Show that this insn will be used in the sequel. */ | |
1769 | INSN_FROM_TARGET_P (candidate) = 0; | |
5317d2f8 | 1770 | return candidate; |
9c7e2978 RK |
1771 | } |
1772 | ||
1773 | /* Unless this is an annulled insn from the target of a branch, | |
1774 | we must stop if it sets anything needed or set by INSN. */ | |
1775 | if ((! INSN_ANNULLED_BRANCH_P (XVECEXP (pat, 0, 0)) | |
1776 | || ! INSN_FROM_TARGET_P (candidate)) | |
1777 | && insn_sets_resource_p (candidate, &needed, 1)) | |
1778 | return 0; | |
1779 | } | |
1780 | ||
1781 | ||
1782 | /* If the insn requiring the delay slot conflicts with INSN, we | |
1783 | must stop. */ | |
1784 | if (insn_sets_resource_p (XVECEXP (pat, 0, 0), &needed, 1)) | |
1785 | return 0; | |
1786 | } | |
1787 | else | |
1788 | { | |
1789 | /* See if TRIAL is the same as INSN. */ | |
1790 | pat = PATTERN (trial); | |
1791 | if (rtx_equal_p (pat, ipat)) | |
5317d2f8 | 1792 | return trial; |
9c7e2978 RK |
1793 | |
1794 | /* Can't go any further if TRIAL conflicts with INSN. */ | |
1795 | if (insn_sets_resource_p (trial, &needed, 1)) | |
1796 | return 0; | |
1797 | } | |
1798 | } | |
1799 | ||
1800 | return 0; | |
1801 | } | |
1802 | \f | |
1803 | /* Return 1 if THREAD can only be executed in one way. If LABEL is non-zero, | |
1804 | it is the target of the branch insn being scanned. If ALLOW_FALLTHROUGH | |
1805 | is non-zero, we are allowed to fall into this thread; otherwise, we are | |
1806 | not. | |
1807 | ||
1808 | If LABEL is used more than one or we pass a label other than LABEL before | |
1809 | finding an active insn, we do not own this thread. */ | |
1810 | ||
1811 | static int | |
1812 | own_thread_p (thread, label, allow_fallthrough) | |
1813 | rtx thread; | |
1814 | rtx label; | |
1815 | int allow_fallthrough; | |
1816 | { | |
1817 | rtx active_insn; | |
1818 | rtx insn; | |
1819 | ||
1820 | /* We don't own the function end. */ | |
1821 | if (thread == 0) | |
1822 | return 0; | |
1823 | ||
1824 | /* Get the first active insn, or THREAD, if it is an active insn. */ | |
1825 | active_insn = next_active_insn (PREV_INSN (thread)); | |
1826 | ||
1827 | for (insn = thread; insn != active_insn; insn = NEXT_INSN (insn)) | |
1828 | if (GET_CODE (insn) == CODE_LABEL | |
1829 | && (insn != label || LABEL_NUSES (insn) != 1)) | |
1830 | return 0; | |
1831 | ||
1832 | if (allow_fallthrough) | |
1833 | return 1; | |
1834 | ||
1835 | /* Ensure that we reach a BARRIER before any insn or label. */ | |
1836 | for (insn = prev_nonnote_insn (thread); | |
1837 | insn == 0 || GET_CODE (insn) != BARRIER; | |
1838 | insn = prev_nonnote_insn (insn)) | |
1839 | if (insn == 0 | |
1840 | || GET_CODE (insn) == CODE_LABEL | |
1841 | || (GET_CODE (insn) == INSN | |
1842 | && GET_CODE (PATTERN (insn)) != USE | |
1843 | && GET_CODE (PATTERN (insn)) != CLOBBER)) | |
1844 | return 0; | |
1845 | ||
1846 | return 1; | |
1847 | } | |
1848 | \f | |
9c7e2978 | 1849 | /* Called when INSN is being moved from a location near the target of a jump. |
aa2c50d6 | 1850 | We leave a marker of the form (use (INSN)) immediately in front |
9c7e2978 | 1851 | of WHERE for mark_target_live_regs. These markers will be deleted when |
aa2c50d6 RK |
1852 | reorg finishes. |
1853 | ||
1854 | We used to try to update the live status of registers if WHERE is at | |
1855 | the start of a basic block, but that can't work since we may remove a | |
1856 | BARRIER in relax_delay_slots. */ | |
9c7e2978 RK |
1857 | |
1858 | static void | |
1859 | update_block (insn, where) | |
1860 | rtx insn; | |
1861 | rtx where; | |
1862 | { | |
1863 | /* Ignore if this was in a delay slot and it came from the target of | |
1864 | a branch. */ | |
1865 | if (INSN_FROM_TARGET_P (insn)) | |
1866 | return; | |
1867 | ||
38a448ca | 1868 | emit_insn_before (gen_rtx_USE (VOIDmode, insn), where); |
9c7e2978 RK |
1869 | |
1870 | /* INSN might be making a value live in a block where it didn't use to | |
1871 | be. So recompute liveness information for this block. */ | |
aa2c50d6 | 1872 | |
ca545bb5 | 1873 | incr_ticks_for_insn (insn); |
9c7e2978 | 1874 | } |
28c9500b | 1875 | |
326f06f7 RK |
1876 | /* Similar to REDIRECT_JUMP except that we update the BB_TICKS entry for |
1877 | the basic block containing the jump. */ | |
1878 | ||
1879 | static int | |
1880 | reorg_redirect_jump (jump, nlabel) | |
1881 | rtx jump; | |
1882 | rtx nlabel; | |
1883 | { | |
ca545bb5 | 1884 | incr_ticks_for_insn (jump); |
326f06f7 RK |
1885 | return redirect_jump (jump, nlabel); |
1886 | } | |
1887 | ||
28c9500b JW |
1888 | /* Called when INSN is being moved forward into a delay slot of DELAYED_INSN. |
1889 | We check every instruction between INSN and DELAYED_INSN for REG_DEAD notes | |
1890 | that reference values used in INSN. If we find one, then we move the | |
1891 | REG_DEAD note to INSN. | |
1892 | ||
1893 | This is needed to handle the case where an later insn (after INSN) has a | |
1894 | REG_DEAD note for a register used by INSN, and this later insn subsequently | |
1895 | gets moved before a CODE_LABEL because it is a redundant insn. In this | |
1896 | case, mark_target_live_regs may be confused into thinking the register | |
1897 | is dead because it sees a REG_DEAD note immediately before a CODE_LABEL. */ | |
1898 | ||
1899 | static void | |
1900 | update_reg_dead_notes (insn, delayed_insn) | |
1901 | rtx insn, delayed_insn; | |
1902 | { | |
1903 | rtx p, link, next; | |
1904 | ||
1905 | for (p = next_nonnote_insn (insn); p != delayed_insn; | |
1906 | p = next_nonnote_insn (p)) | |
1907 | for (link = REG_NOTES (p); link; link = next) | |
1908 | { | |
1909 | next = XEXP (link, 1); | |
1910 | ||
1911 | if (REG_NOTE_KIND (link) != REG_DEAD | |
1912 | || GET_CODE (XEXP (link, 0)) != REG) | |
1913 | continue; | |
1914 | ||
1915 | if (reg_referenced_p (XEXP (link, 0), PATTERN (insn))) | |
1916 | { | |
1917 | /* Move the REG_DEAD note from P to INSN. */ | |
1918 | remove_note (p, link); | |
1919 | XEXP (link, 1) = REG_NOTES (insn); | |
1920 | REG_NOTES (insn) = link; | |
1921 | } | |
1922 | } | |
1923 | } | |
5317d2f8 | 1924 | |
c170c8c2 JW |
1925 | /* Called when an insn redundant with start_insn is deleted. If there |
1926 | is a REG_DEAD note for the target of start_insn between start_insn | |
1927 | and stop_insn, then the REG_DEAD note needs to be deleted since the | |
1928 | value no longer dies there. | |
1929 | ||
1930 | If the REG_DEAD note isn't deleted, then mark_target_live_regs may be | |
1931 | confused into thinking the register is dead. */ | |
1932 | ||
1933 | static void | |
1934 | fix_reg_dead_note (start_insn, stop_insn) | |
1935 | rtx start_insn, stop_insn; | |
1936 | { | |
1937 | rtx p, link, next; | |
1938 | ||
1939 | for (p = next_nonnote_insn (start_insn); p != stop_insn; | |
1940 | p = next_nonnote_insn (p)) | |
1941 | for (link = REG_NOTES (p); link; link = next) | |
1942 | { | |
1943 | next = XEXP (link, 1); | |
1944 | ||
1945 | if (REG_NOTE_KIND (link) != REG_DEAD | |
1946 | || GET_CODE (XEXP (link, 0)) != REG) | |
1947 | continue; | |
1948 | ||
1949 | if (reg_set_p (XEXP (link, 0), PATTERN (start_insn))) | |
1950 | { | |
1951 | remove_note (p, link); | |
1952 | return; | |
1953 | } | |
1954 | } | |
1955 | } | |
1956 | ||
5317d2f8 RK |
1957 | /* Delete any REG_UNUSED notes that exist on INSN but not on REDUNDANT_INSN. |
1958 | ||
1959 | This handles the case of udivmodXi4 instructions which optimize their | |
1960 | output depending on whether any REG_UNUSED notes are present. | |
1961 | we must make sure that INSN calculates as many results as REDUNDANT_INSN | |
1962 | does. */ | |
1963 | ||
1964 | static void | |
1965 | update_reg_unused_notes (insn, redundant_insn) | |
1966 | rtx insn, redundant_insn; | |
1967 | { | |
91a51951 | 1968 | rtx link, next; |
5317d2f8 RK |
1969 | |
1970 | for (link = REG_NOTES (insn); link; link = next) | |
1971 | { | |
1972 | next = XEXP (link, 1); | |
1973 | ||
1974 | if (REG_NOTE_KIND (link) != REG_UNUSED | |
1975 | || GET_CODE (XEXP (link, 0)) != REG) | |
1976 | continue; | |
1977 | ||
1978 | if (! find_regno_note (redundant_insn, REG_UNUSED, | |
1979 | REGNO (XEXP (link, 0)))) | |
1980 | remove_note (insn, link); | |
1981 | } | |
1982 | } | |
9c7e2978 | 1983 | \f |
9c7e2978 RK |
1984 | /* Scan a function looking for insns that need a delay slot and find insns to |
1985 | put into the delay slot. | |
1986 | ||
1987 | NON_JUMPS_P is non-zero if we are to only try to fill non-jump insns (such | |
1988 | as calls). We do these first since we don't want jump insns (that are | |
1989 | easier to fill) to get the only insns that could be used for non-jump insns. | |
1990 | When it is zero, only try to fill JUMP_INSNs. | |
1991 | ||
1992 | When slots are filled in this manner, the insns (including the | |
1993 | delay_insn) are put together in a SEQUENCE rtx. In this fashion, | |
1994 | it is possible to tell whether a delay slot has really been filled | |
1995 | or not. `final' knows how to deal with this, by communicating | |
1996 | through FINAL_SEQUENCE. */ | |
1997 | ||
1998 | static void | |
91a51951 | 1999 | fill_simple_delay_slots (non_jumps_p) |
d8e8f346 | 2000 | int non_jumps_p; |
9c7e2978 RK |
2001 | { |
2002 | register rtx insn, pat, trial, next_trial; | |
91a51951 | 2003 | register int i; |
9c7e2978 RK |
2004 | int num_unfilled_slots = unfilled_slots_next - unfilled_slots_base; |
2005 | struct resources needed, set; | |
126db1fa | 2006 | int slots_to_fill, slots_filled; |
9c7e2978 RK |
2007 | rtx delay_list; |
2008 | ||
2009 | for (i = 0; i < num_unfilled_slots; i++) | |
2010 | { | |
35523fce | 2011 | int flags; |
9c7e2978 RK |
2012 | /* Get the next insn to fill. If it has already had any slots assigned, |
2013 | we can't do anything with it. Maybe we'll improve this later. */ | |
2014 | ||
2015 | insn = unfilled_slots_base[i]; | |
2016 | if (insn == 0 | |
2017 | || INSN_DELETED_P (insn) | |
2018 | || (GET_CODE (insn) == INSN | |
2019 | && GET_CODE (PATTERN (insn)) == SEQUENCE) | |
2020 | || (GET_CODE (insn) == JUMP_INSN && non_jumps_p) | |
2021 | || (GET_CODE (insn) != JUMP_INSN && ! non_jumps_p)) | |
2022 | continue; | |
35523fce | 2023 | |
a2f54138 JL |
2024 | if (GET_CODE (insn) == JUMP_INSN) |
2025 | flags = get_jump_flags (insn, JUMP_LABEL (insn)); | |
2026 | else | |
2027 | flags = get_jump_flags (insn, NULL_RTX); | |
9c7e2978 | 2028 | slots_to_fill = num_delay_slots (insn); |
c3a3b536 JL |
2029 | |
2030 | /* Some machine description have defined instructions to have | |
2031 | delay slots only in certain circumstances which may depend on | |
2032 | nearby insns (which change due to reorg's actions). | |
2033 | ||
2034 | For example, the PA port normally has delay slots for unconditional | |
2035 | jumps. | |
2036 | ||
2037 | However, the PA port claims such jumps do not have a delay slot | |
2038 | if they are immediate successors of certain CALL_INSNs. This | |
2039 | allows the port to favor filling the delay slot of the call with | |
2040 | the unconditional jump. */ | |
9c7e2978 | 2041 | if (slots_to_fill == 0) |
c3a3b536 | 2042 | continue; |
9c7e2978 RK |
2043 | |
2044 | /* This insn needs, or can use, some delay slots. SLOTS_TO_FILL | |
464b453d TW |
2045 | says how many. After initialization, first try optimizing |
2046 | ||
2047 | call _foo call _foo | |
2048 | nop add %o7,.-L1,%o7 | |
2049 | b,a L1 | |
2050 | nop | |
2051 | ||
2052 | If this case applies, the delay slot of the call is filled with | |
2053 | the unconditional jump. This is done first to avoid having the | |
2054 | delay slot of the call filled in the backward scan. Also, since | |
2055 | the unconditional jump is likely to also have a delay slot, that | |
733fa7ef JL |
2056 | insn must exist when it is subsequently scanned. |
2057 | ||
2058 | This is tried on each insn with delay slots as some machines | |
2059 | have insns which perform calls, but are not represented as | |
2060 | CALL_INSNs. */ | |
464b453d TW |
2061 | |
2062 | slots_filled = 0; | |
2063 | delay_list = 0; | |
2064 | ||
733fa7ef | 2065 | if ((trial = next_active_insn (insn)) |
464b453d TW |
2066 | && GET_CODE (trial) == JUMP_INSN |
2067 | && simplejump_p (trial) | |
35523fce | 2068 | && eligible_for_delay (insn, slots_filled, trial, flags) |
464b453d TW |
2069 | && no_labels_between_p (insn, trial)) |
2070 | { | |
45d9a5c6 | 2071 | rtx *tmp; |
464b453d TW |
2072 | slots_filled++; |
2073 | delay_list = add_to_delay_list (trial, delay_list); | |
45d9a5c6 RK |
2074 | |
2075 | /* TRIAL may have had its delay slot filled, then unfilled. When | |
2076 | the delay slot is unfilled, TRIAL is placed back on the unfilled | |
2077 | slots obstack. Unfortunately, it is placed on the end of the | |
2078 | obstack, not in its original location. Therefore, we must search | |
2079 | from entry i + 1 to the end of the unfilled slots obstack to | |
2080 | try and find TRIAL. */ | |
2081 | tmp = &unfilled_slots_base[i + 1]; | |
2082 | while (*tmp != trial && tmp != unfilled_slots_next) | |
2083 | tmp++; | |
2084 | ||
464b453d | 2085 | /* Remove the unconditional jump from consideration for delay slot |
45d9a5c6 RK |
2086 | filling and unthread it. */ |
2087 | if (*tmp == trial) | |
2088 | *tmp = 0; | |
464b453d TW |
2089 | { |
2090 | rtx next = NEXT_INSN (trial); | |
2091 | rtx prev = PREV_INSN (trial); | |
2092 | if (prev) | |
2093 | NEXT_INSN (prev) = next; | |
2094 | if (next) | |
2095 | PREV_INSN (next) = prev; | |
2096 | } | |
2097 | } | |
2098 | ||
2099 | /* Now, scan backwards from the insn to search for a potential | |
2100 | delay-slot candidate. Stop searching when a label or jump is hit. | |
2101 | ||
9c7e2978 RK |
2102 | For each candidate, if it is to go into the delay slot (moved |
2103 | forward in execution sequence), it must not need or set any resources | |
2104 | that were set by later insns and must not set any resources that | |
2105 | are needed for those insns. | |
2106 | ||
2107 | The delay slot insn itself sets resources unless it is a call | |
2108 | (in which case the called routine, not the insn itself, is doing | |
2109 | the setting). */ | |
2110 | ||
464b453d | 2111 | if (slots_filled < slots_to_fill) |
9c7e2978 | 2112 | { |
464b453d TW |
2113 | CLEAR_RESOURCE (&needed); |
2114 | CLEAR_RESOURCE (&set); | |
2115 | mark_set_resources (insn, &set, 0, 0); | |
2116 | mark_referenced_resources (insn, &needed, 0); | |
9c7e2978 | 2117 | |
464b453d TW |
2118 | for (trial = prev_nonnote_insn (insn); ! stop_search_p (trial, 1); |
2119 | trial = next_trial) | |
2120 | { | |
2121 | next_trial = prev_nonnote_insn (trial); | |
9c7e2978 | 2122 | |
464b453d TW |
2123 | /* This must be an INSN or CALL_INSN. */ |
2124 | pat = PATTERN (trial); | |
2125 | ||
2126 | /* USE and CLOBBER at this level was just for flow; ignore it. */ | |
2127 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
2128 | continue; | |
9c7e2978 | 2129 | |
464b453d TW |
2130 | /* Check for resource conflict first, to avoid unnecessary |
2131 | splitting. */ | |
2132 | if (! insn_references_resource_p (trial, &set, 1) | |
2133 | && ! insn_sets_resource_p (trial, &set, 1) | |
2134 | && ! insn_sets_resource_p (trial, &needed, 1) | |
9c7e2978 | 2135 | #ifdef HAVE_cc0 |
464b453d TW |
2136 | /* Can't separate set of cc0 from its use. */ |
2137 | && ! (reg_mentioned_p (cc0_rtx, pat) | |
0d87569a | 2138 | && ! sets_cc0_p (pat)) |
9c7e2978 | 2139 | #endif |
464b453d | 2140 | ) |
9c7e2978 | 2141 | { |
464b453d TW |
2142 | trial = try_split (pat, trial, 1); |
2143 | next_trial = prev_nonnote_insn (trial); | |
35523fce | 2144 | if (eligible_for_delay (insn, slots_filled, trial, flags)) |
464b453d TW |
2145 | { |
2146 | /* In this case, we are searching backward, so if we | |
2147 | find insns to put on the delay list, we want | |
2148 | to put them at the head, rather than the | |
2149 | tail, of the list. */ | |
2150 | ||
28c9500b | 2151 | update_reg_dead_notes (trial, insn); |
38a448ca RH |
2152 | delay_list = gen_rtx_INSN_LIST (VOIDmode, |
2153 | trial, delay_list); | |
464b453d TW |
2154 | update_block (trial, trial); |
2155 | delete_insn (trial); | |
2156 | if (slots_to_fill == ++slots_filled) | |
2157 | break; | |
2158 | continue; | |
2159 | } | |
9c7e2978 | 2160 | } |
9c7e2978 | 2161 | |
464b453d TW |
2162 | mark_set_resources (trial, &set, 0, 1); |
2163 | mark_referenced_resources (trial, &needed, 1); | |
2164 | } | |
9c7e2978 RK |
2165 | } |
2166 | ||
9c7e2978 RK |
2167 | /* If all needed slots haven't been filled, we come here. */ |
2168 | ||
2169 | /* Try to optimize case of jumping around a single insn. */ | |
2170 | #if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS) | |
2f9ba5a9 JL |
2171 | if (slots_filled != slots_to_fill |
2172 | && delay_list == 0 | |
3480bb98 JL |
2173 | && GET_CODE (insn) == JUMP_INSN |
2174 | && (condjump_p (insn) || condjump_in_parallel_p (insn))) | |
9c7e2978 RK |
2175 | { |
2176 | delay_list = optimize_skip (insn); | |
2177 | if (delay_list) | |
2178 | slots_filled += 1; | |
2179 | } | |
2180 | #endif | |
2181 | ||
9c7e2978 RK |
2182 | /* Try to get insns from beyond the insn needing the delay slot. |
2183 | These insns can neither set or reference resources set in insns being | |
2184 | skipped, cannot set resources in the insn being skipped, and, if this | |
2185 | is a CALL_INSN (or a CALL_INSN is passed), cannot trap (because the | |
2186 | call might not return). | |
2187 | ||
f03e51d4 RK |
2188 | There used to be code which continued past the target label if |
2189 | we saw all uses of the target label. This code did not work, | |
2190 | because it failed to account for some instructions which were | |
2191 | both annulled and marked as from the target. This can happen as a | |
2192 | result of optimize_skip. Since this code was redundant with | |
2193 | fill_eager_delay_slots anyways, it was just deleted. */ | |
9c7e2978 | 2194 | |
2f9ba5a9 JL |
2195 | if (slots_filled != slots_to_fill |
2196 | && (GET_CODE (insn) != JUMP_INSN | |
3480bb98 JL |
2197 | || ((condjump_p (insn) || condjump_in_parallel_p (insn)) |
2198 | && ! simplejump_p (insn) | |
2f9ba5a9 | 2199 | && JUMP_LABEL (insn) != 0))) |
9c7e2978 RK |
2200 | { |
2201 | rtx target = 0; | |
2202 | int maybe_never = 0; | |
9c7e2978 RK |
2203 | struct resources needed_at_jump; |
2204 | ||
2205 | CLEAR_RESOURCE (&needed); | |
2206 | CLEAR_RESOURCE (&set); | |
2207 | ||
2208 | if (GET_CODE (insn) == CALL_INSN) | |
2209 | { | |
26d970a5 | 2210 | mark_set_resources (insn, &set, 0, 1); |
9c7e2978 RK |
2211 | mark_referenced_resources (insn, &needed, 1); |
2212 | maybe_never = 1; | |
2213 | } | |
2f9ba5a9 | 2214 | else |
9c7e2978 | 2215 | { |
674345b1 JL |
2216 | mark_set_resources (insn, &set, 0, 1); |
2217 | mark_referenced_resources (insn, &needed, 1); | |
2f9ba5a9 | 2218 | if (GET_CODE (insn) == JUMP_INSN) |
f03e51d4 | 2219 | target = JUMP_LABEL (insn); |
9c7e2978 RK |
2220 | } |
2221 | ||
2222 | for (trial = next_nonnote_insn (insn); trial; trial = next_trial) | |
2223 | { | |
2224 | rtx pat, trial_delay; | |
2225 | ||
2226 | next_trial = next_nonnote_insn (trial); | |
2227 | ||
f03e51d4 RK |
2228 | if (GET_CODE (trial) == CODE_LABEL |
2229 | || GET_CODE (trial) == BARRIER) | |
9c7e2978 RK |
2230 | break; |
2231 | ||
2232 | /* We must have an INSN, JUMP_INSN, or CALL_INSN. */ | |
2233 | pat = PATTERN (trial); | |
2234 | ||
2235 | /* Stand-alone USE and CLOBBER are just for flow. */ | |
2236 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
2237 | continue; | |
2238 | ||
2239 | /* If this already has filled delay slots, get the insn needing | |
2240 | the delay slots. */ | |
2241 | if (GET_CODE (pat) == SEQUENCE) | |
2242 | trial_delay = XVECEXP (pat, 0, 0); | |
2243 | else | |
2244 | trial_delay = trial; | |
2245 | ||
2246 | /* If this is a jump insn to our target, indicate that we have | |
2247 | seen another jump to it. If we aren't handling a conditional | |
2248 | jump, stop our search. Otherwise, compute the needs at its | |
2249 | target and add them to NEEDED. */ | |
2250 | if (GET_CODE (trial_delay) == JUMP_INSN) | |
2251 | { | |
2252 | if (target == 0) | |
2253 | break; | |
f03e51d4 | 2254 | else if (JUMP_LABEL (trial_delay) != target) |
9c7e2978 | 2255 | { |
ca545bb5 BM |
2256 | rtx ninsn = |
2257 | next_active_insn (JUMP_LABEL (trial_delay)); | |
2258 | ||
2259 | mark_target_live_regs (get_insns (), ninsn, | |
2260 | &needed_at_jump); | |
9c7e2978 | 2261 | needed.memory |= needed_at_jump.memory; |
8eae5ed6 | 2262 | needed.unch_memory |= needed_at_jump.unch_memory; |
9c7e2978 RK |
2263 | IOR_HARD_REG_SET (needed.regs, needed_at_jump.regs); |
2264 | } | |
2265 | } | |
2266 | ||
2267 | /* See if we have a resource problem before we try to | |
2268 | split. */ | |
2269 | if (target == 0 | |
2270 | && GET_CODE (pat) != SEQUENCE | |
2271 | && ! insn_references_resource_p (trial, &set, 1) | |
2272 | && ! insn_sets_resource_p (trial, &set, 1) | |
2273 | && ! insn_sets_resource_p (trial, &needed, 1) | |
2274 | #ifdef HAVE_cc0 | |
2275 | && ! (reg_mentioned_p (cc0_rtx, pat) && ! sets_cc0_p (pat)) | |
2276 | #endif | |
2277 | && ! (maybe_never && may_trap_p (pat)) | |
2278 | && (trial = try_split (pat, trial, 0)) | |
35523fce | 2279 | && eligible_for_delay (insn, slots_filled, trial, flags)) |
9c7e2978 RK |
2280 | { |
2281 | next_trial = next_nonnote_insn (trial); | |
2282 | delay_list = add_to_delay_list (trial, delay_list); | |
2283 | ||
2284 | #ifdef HAVE_cc0 | |
2285 | if (reg_mentioned_p (cc0_rtx, pat)) | |
2286 | link_cc0_insns (trial); | |
2287 | #endif | |
2288 | ||
9c7e2978 RK |
2289 | delete_insn (trial); |
2290 | if (slots_to_fill == ++slots_filled) | |
2291 | break; | |
2292 | continue; | |
2293 | } | |
2294 | ||
26d970a5 | 2295 | mark_set_resources (trial, &set, 0, 1); |
9c7e2978 RK |
2296 | mark_referenced_resources (trial, &needed, 1); |
2297 | ||
2298 | /* Ensure we don't put insns between the setting of cc and the | |
2299 | comparison by moving a setting of cc into an earlier delay | |
2300 | slot since these insns could clobber the condition code. */ | |
2301 | set.cc = 1; | |
2302 | ||
2303 | /* If this is a call or jump, we might not get here. */ | |
e4be64d0 RK |
2304 | if (GET_CODE (trial_delay) == CALL_INSN |
2305 | || GET_CODE (trial_delay) == JUMP_INSN) | |
9c7e2978 RK |
2306 | maybe_never = 1; |
2307 | } | |
2308 | ||
2309 | /* If there are slots left to fill and our search was stopped by an | |
2310 | unconditional branch, try the insn at the branch target. We can | |
6f7775d5 JL |
2311 | redirect the branch if it works. |
2312 | ||
2313 | Don't do this if the insn at the branch target is a branch. */ | |
9c7e2978 RK |
2314 | if (slots_to_fill != slots_filled |
2315 | && trial | |
2316 | && GET_CODE (trial) == JUMP_INSN | |
2317 | && simplejump_p (trial) | |
2318 | && (target == 0 || JUMP_LABEL (trial) == target) | |
2319 | && (next_trial = next_active_insn (JUMP_LABEL (trial))) != 0 | |
2320 | && ! (GET_CODE (next_trial) == INSN | |
2321 | && GET_CODE (PATTERN (next_trial)) == SEQUENCE) | |
6f7775d5 | 2322 | && GET_CODE (next_trial) != JUMP_INSN |
9c7e2978 RK |
2323 | && ! insn_references_resource_p (next_trial, &set, 1) |
2324 | && ! insn_sets_resource_p (next_trial, &set, 1) | |
2325 | && ! insn_sets_resource_p (next_trial, &needed, 1) | |
2326 | #ifdef HAVE_cc0 | |
d6749dec | 2327 | && ! reg_mentioned_p (cc0_rtx, PATTERN (next_trial)) |
9c7e2978 RK |
2328 | #endif |
2329 | && ! (maybe_never && may_trap_p (PATTERN (next_trial))) | |
2330 | && (next_trial = try_split (PATTERN (next_trial), next_trial, 0)) | |
35523fce | 2331 | && eligible_for_delay (insn, slots_filled, next_trial, flags)) |
9c7e2978 RK |
2332 | { |
2333 | rtx new_label = next_active_insn (next_trial); | |
2334 | ||
2335 | if (new_label != 0) | |
2336 | new_label = get_label_before (new_label); | |
99f14de7 JW |
2337 | else |
2338 | new_label = find_end_label (); | |
9c7e2978 RK |
2339 | |
2340 | delay_list | |
2341 | = add_to_delay_list (copy_rtx (next_trial), delay_list); | |
2342 | slots_filled++; | |
326f06f7 | 2343 | reorg_redirect_jump (trial, new_label); |
9c7e2978 RK |
2344 | |
2345 | /* If we merged because we both jumped to the same place, | |
2346 | redirect the original insn also. */ | |
2347 | if (target) | |
326f06f7 | 2348 | reorg_redirect_jump (insn, new_label); |
9c7e2978 RK |
2349 | } |
2350 | } | |
2351 | ||
126db1fa JL |
2352 | /* If this is an unconditional jump, then try to get insns from the |
2353 | target of the jump. */ | |
2354 | if (GET_CODE (insn) == JUMP_INSN | |
2355 | && simplejump_p (insn) | |
2356 | && slots_filled != slots_to_fill) | |
2357 | delay_list | |
2358 | = fill_slots_from_thread (insn, const_true_rtx, | |
2359 | next_active_insn (JUMP_LABEL (insn)), | |
2360 | NULL, 1, 1, | |
2361 | own_thread_p (JUMP_LABEL (insn), | |
2362 | JUMP_LABEL (insn), 0), | |
ab63953e JL |
2363 | slots_to_fill, &slots_filled, |
2364 | delay_list); | |
126db1fa | 2365 | |
9c7e2978 RK |
2366 | if (delay_list) |
2367 | unfilled_slots_base[i] | |
91a51951 | 2368 | = emit_delay_sequence (insn, delay_list, slots_filled); |
9c7e2978 RK |
2369 | |
2370 | if (slots_to_fill == slots_filled) | |
2371 | unfilled_slots_base[i] = 0; | |
2372 | ||
2373 | note_delay_statistics (slots_filled, 0); | |
2374 | } | |
2375 | ||
2376 | #ifdef DELAY_SLOTS_FOR_EPILOGUE | |
2377 | /* See if the epilogue needs any delay slots. Try to fill them if so. | |
2378 | The only thing we can do is scan backwards from the end of the | |
2379 | function. If we did this in a previous pass, it is incorrect to do it | |
2380 | again. */ | |
2381 | if (current_function_epilogue_delay_list) | |
2382 | return; | |
2383 | ||
2384 | slots_to_fill = DELAY_SLOTS_FOR_EPILOGUE; | |
2385 | if (slots_to_fill == 0) | |
2386 | return; | |
2387 | ||
2388 | slots_filled = 0; | |
9c7e2978 RK |
2389 | CLEAR_RESOURCE (&set); |
2390 | ||
8c2977e2 JW |
2391 | /* The frame pointer and stack pointer are needed at the beginning of |
2392 | the epilogue, so instructions setting them can not be put in the | |
2393 | epilogue delay slot. However, everything else needed at function | |
2394 | end is safe, so we don't want to use end_of_function_needs here. */ | |
2395 | CLEAR_RESOURCE (&needed); | |
2396 | if (frame_pointer_needed) | |
2397 | { | |
2398 | SET_HARD_REG_BIT (needed.regs, FRAME_POINTER_REGNUM); | |
2399 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2400 | SET_HARD_REG_BIT (needed.regs, HARD_FRAME_POINTER_REGNUM); | |
2401 | #endif | |
2402 | #ifdef EXIT_IGNORE_STACK | |
fdb8a883 JW |
2403 | if (! EXIT_IGNORE_STACK |
2404 | || current_function_sp_is_unchanging) | |
8c2977e2 JW |
2405 | #endif |
2406 | SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM); | |
2407 | } | |
2408 | else | |
2409 | SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM); | |
2410 | ||
632c9d9e MS |
2411 | #ifdef EPILOGUE_USES |
2412 | for (i = 0; i <FIRST_PSEUDO_REGISTER; i++) | |
2413 | { | |
2414 | if (EPILOGUE_USES (i)) | |
2415 | SET_HARD_REG_BIT (needed.regs, i); | |
2416 | } | |
2417 | #endif | |
2418 | ||
9c7e2978 RK |
2419 | for (trial = get_last_insn (); ! stop_search_p (trial, 1); |
2420 | trial = PREV_INSN (trial)) | |
2421 | { | |
2422 | if (GET_CODE (trial) == NOTE) | |
2423 | continue; | |
2424 | pat = PATTERN (trial); | |
2425 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
2426 | continue; | |
2427 | ||
2428 | if (! insn_references_resource_p (trial, &set, 1) | |
2429 | && ! insn_sets_resource_p (trial, &needed, 1) | |
8c2977e2 | 2430 | && ! insn_sets_resource_p (trial, &set, 1) |
9c7e2978 RK |
2431 | #ifdef HAVE_cc0 |
2432 | /* Don't want to mess with cc0 here. */ | |
2433 | && ! reg_mentioned_p (cc0_rtx, pat) | |
2434 | #endif | |
2435 | ) | |
2436 | { | |
2437 | trial = try_split (pat, trial, 1); | |
2438 | if (ELIGIBLE_FOR_EPILOGUE_DELAY (trial, slots_filled)) | |
2439 | { | |
17448690 RK |
2440 | /* Here as well we are searching backward, so put the |
2441 | insns we find on the head of the list. */ | |
2442 | ||
9c7e2978 | 2443 | current_function_epilogue_delay_list |
38a448ca RH |
2444 | = gen_rtx_INSN_LIST (VOIDmode, trial, |
2445 | current_function_epilogue_delay_list); | |
ca545bb5 | 2446 | mark_end_of_function_resources (trial, 1); |
9c7e2978 RK |
2447 | update_block (trial, trial); |
2448 | delete_insn (trial); | |
2449 | ||
2450 | /* Clear deleted bit so final.c will output the insn. */ | |
2451 | INSN_DELETED_P (trial) = 0; | |
2452 | ||
2453 | if (slots_to_fill == ++slots_filled) | |
2454 | break; | |
2455 | continue; | |
2456 | } | |
2457 | } | |
2458 | ||
26d970a5 | 2459 | mark_set_resources (trial, &set, 0, 1); |
9c7e2978 RK |
2460 | mark_referenced_resources (trial, &needed, 1); |
2461 | } | |
2462 | ||
2463 | note_delay_statistics (slots_filled, 0); | |
2464 | #endif | |
2465 | } | |
2466 | \f | |
2467 | /* Try to find insns to place in delay slots. | |
2468 | ||
2469 | INSN is the jump needing SLOTS_TO_FILL delay slots. It tests CONDITION | |
2470 | or is an unconditional branch if CONDITION is const_true_rtx. | |
2471 | *PSLOTS_FILLED is updated with the number of slots that we have filled. | |
2472 | ||
2473 | THREAD is a flow-of-control, either the insns to be executed if the | |
2474 | branch is true or if the branch is false, THREAD_IF_TRUE says which. | |
2475 | ||
2476 | OPPOSITE_THREAD is the thread in the opposite direction. It is used | |
2477 | to see if any potential delay slot insns set things needed there. | |
2478 | ||
2479 | LIKELY is non-zero if it is extremely likely that the branch will be | |
2480 | taken and THREAD_IF_TRUE is set. This is used for the branch at the | |
2481 | end of a loop back up to the top. | |
2482 | ||
2483 | OWN_THREAD and OWN_OPPOSITE_THREAD are true if we are the only user of the | |
2484 | thread. I.e., it is the fallthrough code of our jump or the target of the | |
2485 | jump when we are the only jump going there. | |
2486 | ||
2487 | If OWN_THREAD is false, it must be the "true" thread of a jump. In that | |
2488 | case, we can only take insns from the head of the thread for our delay | |
2489 | slot. We then adjust the jump to point after the insns we have taken. */ | |
2490 | ||
2491 | static rtx | |
2492 | fill_slots_from_thread (insn, condition, thread, opposite_thread, likely, | |
91a51951 | 2493 | thread_if_true, own_thread, |
ab63953e | 2494 | slots_to_fill, pslots_filled, delay_list) |
9c7e2978 RK |
2495 | rtx insn; |
2496 | rtx condition; | |
2497 | rtx thread, opposite_thread; | |
2498 | int likely; | |
2499 | int thread_if_true; | |
91a51951 | 2500 | int own_thread; |
9c7e2978 | 2501 | int slots_to_fill, *pslots_filled; |
ab63953e | 2502 | rtx delay_list; |
9c7e2978 | 2503 | { |
d674b9e3 | 2504 | rtx new_thread; |
9c7e2978 RK |
2505 | struct resources opposite_needed, set, needed; |
2506 | rtx trial; | |
2507 | int lose = 0; | |
2508 | int must_annul = 0; | |
35523fce | 2509 | int flags; |
9c7e2978 RK |
2510 | |
2511 | /* Validate our arguments. */ | |
2512 | if ((condition == const_true_rtx && ! thread_if_true) | |
2513 | || (! own_thread && ! thread_if_true)) | |
2514 | abort (); | |
2515 | ||
35523fce JL |
2516 | flags = get_jump_flags (insn, JUMP_LABEL (insn)); |
2517 | ||
9c7e2978 RK |
2518 | /* If our thread is the end of subroutine, we can't get any delay |
2519 | insns from that. */ | |
2520 | if (thread == 0) | |
ab63953e | 2521 | return delay_list; |
9c7e2978 RK |
2522 | |
2523 | /* If this is an unconditional branch, nothing is needed at the | |
2524 | opposite thread. Otherwise, compute what is needed there. */ | |
2525 | if (condition == const_true_rtx) | |
2526 | CLEAR_RESOURCE (&opposite_needed); | |
2527 | else | |
ca545bb5 | 2528 | mark_target_live_regs (get_insns (), opposite_thread, &opposite_needed); |
9c7e2978 | 2529 | |
d674b9e3 RK |
2530 | /* If the insn at THREAD can be split, do it here to avoid having to |
2531 | update THREAD and NEW_THREAD if it is done in the loop below. Also | |
2532 | initialize NEW_THREAD. */ | |
2533 | ||
d45cf215 | 2534 | new_thread = thread = try_split (PATTERN (thread), thread, 0); |
d674b9e3 | 2535 | |
9c7e2978 RK |
2536 | /* Scan insns at THREAD. We are looking for an insn that can be removed |
2537 | from THREAD (it neither sets nor references resources that were set | |
2538 | ahead of it and it doesn't set anything needs by the insns ahead of | |
2539 | it) and that either can be placed in an annulling insn or aren't | |
2540 | needed at OPPOSITE_THREAD. */ | |
2541 | ||
2542 | CLEAR_RESOURCE (&needed); | |
2543 | CLEAR_RESOURCE (&set); | |
2544 | ||
2545 | /* If we do not own this thread, we must stop as soon as we find | |
2546 | something that we can't put in a delay slot, since all we can do | |
2547 | is branch into THREAD at a later point. Therefore, labels stop | |
2548 | the search if this is not the `true' thread. */ | |
2549 | ||
2550 | for (trial = thread; | |
2551 | ! stop_search_p (trial, ! thread_if_true) && (! lose || own_thread); | |
2552 | trial = next_nonnote_insn (trial)) | |
2553 | { | |
70011923 | 2554 | rtx pat, old_trial; |
9c7e2978 RK |
2555 | |
2556 | /* If we have passed a label, we no longer own this thread. */ | |
2557 | if (GET_CODE (trial) == CODE_LABEL) | |
2558 | { | |
2559 | own_thread = 0; | |
2560 | continue; | |
2561 | } | |
2562 | ||
2563 | pat = PATTERN (trial); | |
2564 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
2565 | continue; | |
2566 | ||
2567 | /* If TRIAL conflicts with the insns ahead of it, we lose. Also, | |
2568 | don't separate or copy insns that set and use CC0. */ | |
2569 | if (! insn_references_resource_p (trial, &set, 1) | |
2570 | && ! insn_sets_resource_p (trial, &set, 1) | |
2571 | && ! insn_sets_resource_p (trial, &needed, 1) | |
2572 | #ifdef HAVE_cc0 | |
2573 | && ! (reg_mentioned_p (cc0_rtx, pat) | |
2574 | && (! own_thread || ! sets_cc0_p (pat))) | |
2575 | #endif | |
2576 | ) | |
2577 | { | |
5317d2f8 RK |
2578 | rtx prior_insn; |
2579 | ||
9c7e2978 RK |
2580 | /* If TRIAL is redundant with some insn before INSN, we don't |
2581 | actually need to add it to the delay list; we can merely pretend | |
2582 | we did. */ | |
91a51951 | 2583 | if ((prior_insn = redundant_insn (trial, insn, delay_list))) |
9c7e2978 | 2584 | { |
c170c8c2 | 2585 | fix_reg_dead_note (prior_insn, insn); |
9c7e2978 RK |
2586 | if (own_thread) |
2587 | { | |
f1f9081a | 2588 | update_block (trial, thread); |
9bfe7965 | 2589 | if (trial == thread) |
8b11645c RK |
2590 | { |
2591 | thread = next_active_insn (thread); | |
2592 | if (new_thread == trial) | |
2593 | new_thread = thread; | |
2594 | } | |
9bfe7965 | 2595 | |
9c7e2978 RK |
2596 | delete_insn (trial); |
2597 | } | |
2598 | else | |
5317d2f8 RK |
2599 | { |
2600 | update_reg_unused_notes (prior_insn, trial); | |
088131ee | 2601 | new_thread = next_active_insn (trial); |
5317d2f8 | 2602 | } |
9c7e2978 RK |
2603 | |
2604 | continue; | |
2605 | } | |
2606 | ||
2607 | /* There are two ways we can win: If TRIAL doesn't set anything | |
2608 | needed at the opposite thread and can't trap, or if it can | |
2609 | go into an annulled delay slot. */ | |
96960d10 HB |
2610 | if (!must_annul |
2611 | && (condition == const_true_rtx | |
2612 | || (! insn_sets_resource_p (trial, &opposite_needed, 1) | |
2613 | && ! may_trap_p (pat)))) | |
9c7e2978 | 2614 | { |
70011923 | 2615 | old_trial = trial; |
9c7e2978 | 2616 | trial = try_split (pat, trial, 0); |
70011923 ILT |
2617 | if (new_thread == old_trial) |
2618 | new_thread = trial; | |
9b9cd81b JW |
2619 | if (thread == old_trial) |
2620 | thread = trial; | |
9c7e2978 | 2621 | pat = PATTERN (trial); |
35523fce | 2622 | if (eligible_for_delay (insn, *pslots_filled, trial, flags)) |
9c7e2978 RK |
2623 | goto winner; |
2624 | } | |
2625 | else if (0 | |
2626 | #ifdef ANNUL_IFTRUE_SLOTS | |
2627 | || ! thread_if_true | |
2628 | #endif | |
2629 | #ifdef ANNUL_IFFALSE_SLOTS | |
2630 | || thread_if_true | |
2631 | #endif | |
2632 | ) | |
2633 | { | |
70011923 | 2634 | old_trial = trial; |
9c7e2978 | 2635 | trial = try_split (pat, trial, 0); |
70011923 ILT |
2636 | if (new_thread == old_trial) |
2637 | new_thread = trial; | |
760607e8 RK |
2638 | if (thread == old_trial) |
2639 | thread = trial; | |
9c7e2978 | 2640 | pat = PATTERN (trial); |
96960d10 HB |
2641 | if ((must_annul || delay_list == NULL) && (thread_if_true |
2642 | ? check_annul_list_true_false (0, delay_list) | |
2643 | && eligible_for_annul_false (insn, *pslots_filled, trial, flags) | |
2644 | : check_annul_list_true_false (1, delay_list) | |
2645 | && eligible_for_annul_true (insn, *pslots_filled, trial, flags))) | |
9c7e2978 RK |
2646 | { |
2647 | rtx temp; | |
2648 | ||
2649 | must_annul = 1; | |
2650 | winner: | |
2651 | ||
2652 | #ifdef HAVE_cc0 | |
2653 | if (reg_mentioned_p (cc0_rtx, pat)) | |
2654 | link_cc0_insns (trial); | |
2655 | #endif | |
2656 | ||
2657 | /* If we own this thread, delete the insn. If this is the | |
2658 | destination of a branch, show that a basic block status | |
2659 | may have been updated. In any case, mark the new | |
2660 | starting point of this thread. */ | |
2661 | if (own_thread) | |
2662 | { | |
f1f9081a | 2663 | update_block (trial, thread); |
a7ad699e RK |
2664 | if (trial == thread) |
2665 | { | |
2666 | thread = next_active_insn (thread); | |
2667 | if (new_thread == trial) | |
2668 | new_thread = thread; | |
2669 | } | |
9c7e2978 RK |
2670 | delete_insn (trial); |
2671 | } | |
2672 | else | |
2673 | new_thread = next_active_insn (trial); | |
2674 | ||
2675 | temp = own_thread ? trial : copy_rtx (trial); | |
2676 | if (thread_if_true) | |
2677 | INSN_FROM_TARGET_P (temp) = 1; | |
2678 | ||
2679 | delay_list = add_to_delay_list (temp, delay_list); | |
2680 | ||
2681 | if (slots_to_fill == ++(*pslots_filled)) | |
2682 | { | |
2683 | /* Even though we have filled all the slots, we | |
2684 | may be branching to a location that has a | |
2685 | redundant insn. Skip any if so. */ | |
2686 | while (new_thread && ! own_thread | |
2687 | && ! insn_sets_resource_p (new_thread, &set, 1) | |
2688 | && ! insn_sets_resource_p (new_thread, &needed, 1) | |
2689 | && ! insn_references_resource_p (new_thread, | |
2690 | &set, 1) | |
f78c792c JL |
2691 | && (prior_insn |
2692 | = redundant_insn (new_thread, insn, | |
2693 | delay_list))) | |
2694 | { | |
2695 | /* We know we do not own the thread, so no need | |
2696 | to call update_block and delete_insn. */ | |
2697 | fix_reg_dead_note (prior_insn, insn); | |
2698 | update_reg_unused_notes (prior_insn, new_thread); | |
2699 | new_thread = next_active_insn (new_thread); | |
2700 | } | |
9c7e2978 RK |
2701 | break; |
2702 | } | |
2703 | ||
2704 | continue; | |
2705 | } | |
2706 | } | |
2707 | } | |
2708 | ||
2709 | /* This insn can't go into a delay slot. */ | |
2710 | lose = 1; | |
26d970a5 | 2711 | mark_set_resources (trial, &set, 0, 1); |
9c7e2978 RK |
2712 | mark_referenced_resources (trial, &needed, 1); |
2713 | ||
2714 | /* Ensure we don't put insns between the setting of cc and the comparison | |
2715 | by moving a setting of cc into an earlier delay slot since these insns | |
2716 | could clobber the condition code. */ | |
2717 | set.cc = 1; | |
2718 | ||
2719 | /* If this insn is a register-register copy and the next insn has | |
2720 | a use of our destination, change it to use our source. That way, | |
2721 | it will become a candidate for our delay slot the next time | |
2722 | through this loop. This case occurs commonly in loops that | |
2723 | scan a list. | |
2724 | ||
2725 | We could check for more complex cases than those tested below, | |
2726 | but it doesn't seem worth it. It might also be a good idea to try | |
9b72fab4 RK |
2727 | to swap the two insns. That might do better. |
2728 | ||
963d6142 RK |
2729 | We can't do this if the next insn modifies our destination, because |
2730 | that would make the replacement into the insn invalid. We also can't | |
2731 | do this if it modifies our source, because it might be an earlyclobber | |
2732 | operand. This latter test also prevents updating the contents of | |
2733 | a PRE_INC. */ | |
9c7e2978 RK |
2734 | |
2735 | if (GET_CODE (trial) == INSN && GET_CODE (pat) == SET | |
2736 | && GET_CODE (SET_SRC (pat)) == REG | |
2737 | && GET_CODE (SET_DEST (pat)) == REG) | |
2738 | { | |
2739 | rtx next = next_nonnote_insn (trial); | |
9c7e2978 RK |
2740 | |
2741 | if (next && GET_CODE (next) == INSN | |
9b72fab4 RK |
2742 | && GET_CODE (PATTERN (next)) != USE |
2743 | && ! reg_set_p (SET_DEST (pat), next) | |
963d6142 | 2744 | && ! reg_set_p (SET_SRC (pat), next) |
9b72fab4 | 2745 | && reg_referenced_p (SET_DEST (pat), PATTERN (next))) |
9c7e2978 RK |
2746 | validate_replace_rtx (SET_DEST (pat), SET_SRC (pat), next); |
2747 | } | |
2748 | } | |
2749 | ||
2750 | /* If we stopped on a branch insn that has delay slots, see if we can | |
2751 | steal some of the insns in those slots. */ | |
2752 | if (trial && GET_CODE (trial) == INSN | |
2753 | && GET_CODE (PATTERN (trial)) == SEQUENCE | |
2754 | && GET_CODE (XVECEXP (PATTERN (trial), 0, 0)) == JUMP_INSN) | |
2755 | { | |
2756 | /* If this is the `true' thread, we will want to follow the jump, | |
2757 | so we can only do this if we have taken everything up to here. */ | |
18e765cb | 2758 | if (thread_if_true && trial == new_thread) |
9c7e2978 RK |
2759 | delay_list |
2760 | = steal_delay_list_from_target (insn, condition, PATTERN (trial), | |
2761 | delay_list, &set, &needed, | |
2762 | &opposite_needed, slots_to_fill, | |
2763 | pslots_filled, &must_annul, | |
2764 | &new_thread); | |
2765 | else if (! thread_if_true) | |
2766 | delay_list | |
2767 | = steal_delay_list_from_fallthrough (insn, condition, | |
2768 | PATTERN (trial), | |
2769 | delay_list, &set, &needed, | |
2770 | &opposite_needed, slots_to_fill, | |
2771 | pslots_filled, &must_annul); | |
2772 | } | |
2773 | ||
2774 | /* If we haven't found anything for this delay slot and it is very | |
2775 | likely that the branch will be taken, see if the insn at our target | |
d674b9e3 RK |
2776 | increments or decrements a register with an increment that does not |
2777 | depend on the destination register. If so, try to place the opposite | |
9c7e2978 RK |
2778 | arithmetic insn after the jump insn and put the arithmetic insn in the |
2779 | delay slot. If we can't do this, return. */ | |
a0a7cb35 JL |
2780 | if (delay_list == 0 && likely && new_thread |
2781 | && GET_CODE (new_thread) == INSN | |
2782 | && GET_CODE (PATTERN (new_thread)) != ASM_INPUT | |
2783 | && asm_noperands (PATTERN (new_thread)) < 0) | |
9c7e2978 RK |
2784 | { |
2785 | rtx pat = PATTERN (new_thread); | |
2786 | rtx dest; | |
2787 | rtx src; | |
2788 | ||
d674b9e3 | 2789 | trial = new_thread; |
9c7e2978 RK |
2790 | pat = PATTERN (trial); |
2791 | ||
2792 | if (GET_CODE (trial) != INSN || GET_CODE (pat) != SET | |
35523fce | 2793 | || ! eligible_for_delay (insn, 0, trial, flags)) |
9c7e2978 RK |
2794 | return 0; |
2795 | ||
2796 | dest = SET_DEST (pat), src = SET_SRC (pat); | |
2797 | if ((GET_CODE (src) == PLUS || GET_CODE (src) == MINUS) | |
d674b9e3 RK |
2798 | && rtx_equal_p (XEXP (src, 0), dest) |
2799 | && ! reg_overlap_mentioned_p (dest, XEXP (src, 1))) | |
9c7e2978 RK |
2800 | { |
2801 | rtx other = XEXP (src, 1); | |
2802 | rtx new_arith; | |
2803 | rtx ninsn; | |
2804 | ||
2805 | /* If this is a constant adjustment, use the same code with | |
2806 | the negated constant. Otherwise, reverse the sense of the | |
2807 | arithmetic. */ | |
2808 | if (GET_CODE (other) == CONST_INT) | |
38a448ca RH |
2809 | new_arith = gen_rtx_fmt_ee (GET_CODE (src), GET_MODE (src), dest, |
2810 | negate_rtx (GET_MODE (src), other)); | |
9c7e2978 | 2811 | else |
38a448ca RH |
2812 | new_arith = gen_rtx_fmt_ee (GET_CODE (src) == PLUS ? MINUS : PLUS, |
2813 | GET_MODE (src), dest, other); | |
9c7e2978 | 2814 | |
38a448ca | 2815 | ninsn = emit_insn_after (gen_rtx_SET (VOIDmode, dest, new_arith), |
9c7e2978 RK |
2816 | insn); |
2817 | ||
2818 | if (recog_memoized (ninsn) < 0 | |
0eadeb15 | 2819 | || (extract_insn (ninsn), ! constrain_operands (1))) |
9c7e2978 RK |
2820 | { |
2821 | delete_insn (ninsn); | |
2822 | return 0; | |
2823 | } | |
2824 | ||
2825 | if (own_thread) | |
2826 | { | |
f1f9081a | 2827 | update_block (trial, thread); |
a7ad699e RK |
2828 | if (trial == thread) |
2829 | { | |
2830 | thread = next_active_insn (thread); | |
2831 | if (new_thread == trial) | |
2832 | new_thread = thread; | |
2833 | } | |
9c7e2978 RK |
2834 | delete_insn (trial); |
2835 | } | |
2836 | else | |
2837 | new_thread = next_active_insn (trial); | |
2838 | ||
2839 | ninsn = own_thread ? trial : copy_rtx (trial); | |
2840 | if (thread_if_true) | |
2841 | INSN_FROM_TARGET_P (ninsn) = 1; | |
2842 | ||
fb3821f7 | 2843 | delay_list = add_to_delay_list (ninsn, NULL_RTX); |
9c7e2978 RK |
2844 | (*pslots_filled)++; |
2845 | } | |
2846 | } | |
2847 | ||
2848 | if (delay_list && must_annul) | |
2849 | INSN_ANNULLED_BRANCH_P (insn) = 1; | |
2850 | ||
2851 | /* If we are to branch into the middle of this thread, find an appropriate | |
2852 | label or make a new one if none, and redirect INSN to it. If we hit the | |
2853 | end of the function, use the end-of-function label. */ | |
2854 | if (new_thread != thread) | |
2855 | { | |
2856 | rtx label; | |
2857 | ||
2858 | if (! thread_if_true) | |
2859 | abort (); | |
2860 | ||
2861 | if (new_thread && GET_CODE (new_thread) == JUMP_INSN | |
2862 | && (simplejump_p (new_thread) | |
b304ad47 JL |
2863 | || GET_CODE (PATTERN (new_thread)) == RETURN) |
2864 | && redirect_with_delay_list_safe_p (insn, | |
2865 | JUMP_LABEL (new_thread), | |
2866 | delay_list)) | |
22422dbf | 2867 | new_thread = follow_jumps (JUMP_LABEL (new_thread)); |
9c7e2978 RK |
2868 | |
2869 | if (new_thread == 0) | |
2870 | label = find_end_label (); | |
2871 | else if (GET_CODE (new_thread) == CODE_LABEL) | |
2872 | label = new_thread; | |
2873 | else | |
2874 | label = get_label_before (new_thread); | |
2875 | ||
326f06f7 | 2876 | reorg_redirect_jump (insn, label); |
9c7e2978 RK |
2877 | } |
2878 | ||
2879 | return delay_list; | |
2880 | } | |
2881 | \f | |
2882 | /* Make another attempt to find insns to place in delay slots. | |
2883 | ||
2884 | We previously looked for insns located in front of the delay insn | |
2885 | and, for non-jump delay insns, located behind the delay insn. | |
2886 | ||
2887 | Here only try to schedule jump insns and try to move insns from either | |
2888 | the target or the following insns into the delay slot. If annulling is | |
2889 | supported, we will be likely to do this. Otherwise, we can do this only | |
2890 | if safe. */ | |
2891 | ||
2892 | static void | |
91a51951 | 2893 | fill_eager_delay_slots () |
9c7e2978 RK |
2894 | { |
2895 | register rtx insn; | |
2896 | register int i; | |
2897 | int num_unfilled_slots = unfilled_slots_next - unfilled_slots_base; | |
2898 | ||
2899 | for (i = 0; i < num_unfilled_slots; i++) | |
2900 | { | |
2901 | rtx condition; | |
2902 | rtx target_label, insn_at_target, fallthrough_insn; | |
2903 | rtx delay_list = 0; | |
2904 | int own_target; | |
2905 | int own_fallthrough; | |
2906 | int prediction, slots_to_fill, slots_filled; | |
2907 | ||
2908 | insn = unfilled_slots_base[i]; | |
2909 | if (insn == 0 | |
2910 | || INSN_DELETED_P (insn) | |
2911 | || GET_CODE (insn) != JUMP_INSN | |
3480bb98 | 2912 | || ! (condjump_p (insn) || condjump_in_parallel_p (insn))) |
9c7e2978 RK |
2913 | continue; |
2914 | ||
2915 | slots_to_fill = num_delay_slots (insn); | |
c3a3b536 JL |
2916 | /* Some machine description have defined instructions to have |
2917 | delay slots only in certain circumstances which may depend on | |
2918 | nearby insns (which change due to reorg's actions). | |
2919 | ||
2920 | For example, the PA port normally has delay slots for unconditional | |
2921 | jumps. | |
2922 | ||
2923 | However, the PA port claims such jumps do not have a delay slot | |
2924 | if they are immediate successors of certain CALL_INSNs. This | |
2925 | allows the port to favor filling the delay slot of the call with | |
2926 | the unconditional jump. */ | |
9c7e2978 | 2927 | if (slots_to_fill == 0) |
c3a3b536 | 2928 | continue; |
9c7e2978 RK |
2929 | |
2930 | slots_filled = 0; | |
2931 | target_label = JUMP_LABEL (insn); | |
2932 | condition = get_branch_condition (insn, target_label); | |
2933 | ||
2934 | if (condition == 0) | |
2935 | continue; | |
2936 | ||
abc95ed3 | 2937 | /* Get the next active fallthrough and target insns and see if we own |
9c7e2978 RK |
2938 | them. Then see whether the branch is likely true. We don't need |
2939 | to do a lot of this for unconditional branches. */ | |
2940 | ||
2941 | insn_at_target = next_active_insn (target_label); | |
2942 | own_target = own_thread_p (target_label, target_label, 0); | |
2943 | ||
2944 | if (condition == const_true_rtx) | |
2945 | { | |
2946 | own_fallthrough = 0; | |
2947 | fallthrough_insn = 0; | |
2948 | prediction = 2; | |
2949 | } | |
2950 | else | |
2951 | { | |
2952 | fallthrough_insn = next_active_insn (insn); | |
fb3821f7 | 2953 | own_fallthrough = own_thread_p (NEXT_INSN (insn), NULL_RTX, 1); |
9c7e2978 RK |
2954 | prediction = mostly_true_jump (insn, condition); |
2955 | } | |
2956 | ||
2957 | /* If this insn is expected to branch, first try to get insns from our | |
2958 | target, then our fallthrough insns. If it is not, expected to branch, | |
2959 | try the other order. */ | |
2960 | ||
0275a51b | 2961 | if (prediction > 0) |
9c7e2978 RK |
2962 | { |
2963 | delay_list | |
2964 | = fill_slots_from_thread (insn, condition, insn_at_target, | |
2965 | fallthrough_insn, prediction == 2, 1, | |
91a51951 | 2966 | own_target, |
ab63953e | 2967 | slots_to_fill, &slots_filled, delay_list); |
9c7e2978 RK |
2968 | |
2969 | if (delay_list == 0 && own_fallthrough) | |
2970 | { | |
2971 | /* Even though we didn't find anything for delay slots, | |
2972 | we might have found a redundant insn which we deleted | |
2973 | from the thread that was filled. So we have to recompute | |
2974 | the next insn at the target. */ | |
2975 | target_label = JUMP_LABEL (insn); | |
2976 | insn_at_target = next_active_insn (target_label); | |
2977 | ||
2978 | delay_list | |
2979 | = fill_slots_from_thread (insn, condition, fallthrough_insn, | |
2980 | insn_at_target, 0, 0, | |
91a51951 | 2981 | own_fallthrough, |
ab63953e JL |
2982 | slots_to_fill, &slots_filled, |
2983 | delay_list); | |
9c7e2978 RK |
2984 | } |
2985 | } | |
2986 | else | |
2987 | { | |
2988 | if (own_fallthrough) | |
2989 | delay_list | |
2990 | = fill_slots_from_thread (insn, condition, fallthrough_insn, | |
2991 | insn_at_target, 0, 0, | |
91a51951 | 2992 | own_fallthrough, |
d9f1e3da MH |
2993 | slots_to_fill, &slots_filled, |
2994 | delay_list); | |
9c7e2978 RK |
2995 | |
2996 | if (delay_list == 0) | |
2997 | delay_list | |
2998 | = fill_slots_from_thread (insn, condition, insn_at_target, | |
2999 | next_active_insn (insn), 0, 1, | |
91a51951 | 3000 | own_target, |
ab63953e JL |
3001 | slots_to_fill, &slots_filled, |
3002 | delay_list); | |
9c7e2978 RK |
3003 | } |
3004 | ||
3005 | if (delay_list) | |
3006 | unfilled_slots_base[i] | |
91a51951 | 3007 | = emit_delay_sequence (insn, delay_list, slots_filled); |
9c7e2978 RK |
3008 | |
3009 | if (slots_to_fill == slots_filled) | |
3010 | unfilled_slots_base[i] = 0; | |
3011 | ||
3012 | note_delay_statistics (slots_filled, 1); | |
3013 | } | |
3014 | } | |
3015 | \f | |
3016 | /* Once we have tried two ways to fill a delay slot, make a pass over the | |
3017 | code to try to improve the results and to do such things as more jump | |
3018 | threading. */ | |
3019 | ||
3020 | static void | |
3021 | relax_delay_slots (first) | |
3022 | rtx first; | |
3023 | { | |
3024 | register rtx insn, next, pat; | |
3025 | register rtx trial, delay_insn, target_label; | |
3026 | ||
3027 | /* Look at every JUMP_INSN and see if we can improve it. */ | |
3028 | for (insn = first; insn; insn = next) | |
3029 | { | |
3030 | rtx other; | |
3031 | ||
3032 | next = next_active_insn (insn); | |
3033 | ||
3034 | /* If this is a jump insn, see if it now jumps to a jump, jumps to | |
3035 | the next insn, or jumps to a label that is not the last of a | |
3036 | group of consecutive labels. */ | |
3037 | if (GET_CODE (insn) == JUMP_INSN | |
3480bb98 | 3038 | && (condjump_p (insn) || condjump_in_parallel_p (insn)) |
9c7e2978 RK |
3039 | && (target_label = JUMP_LABEL (insn)) != 0) |
3040 | { | |
22422dbf | 3041 | target_label = follow_jumps (target_label); |
9c7e2978 RK |
3042 | target_label = prev_label (next_active_insn (target_label)); |
3043 | ||
de5292c7 RK |
3044 | if (target_label == 0) |
3045 | target_label = find_end_label (); | |
3046 | ||
3480bb98 JL |
3047 | if (next_active_insn (target_label) == next |
3048 | && ! condjump_in_parallel_p (insn)) | |
9c7e2978 RK |
3049 | { |
3050 | delete_jump (insn); | |
3051 | continue; | |
3052 | } | |
3053 | ||
3054 | if (target_label != JUMP_LABEL (insn)) | |
326f06f7 | 3055 | reorg_redirect_jump (insn, target_label); |
9c7e2978 RK |
3056 | |
3057 | /* See if this jump branches around a unconditional jump. | |
3058 | If so, invert this jump and point it to the target of the | |
3059 | second jump. */ | |
3060 | if (next && GET_CODE (next) == JUMP_INSN | |
3061 | && (simplejump_p (next) || GET_CODE (PATTERN (next)) == RETURN) | |
3062 | && next_active_insn (target_label) == next_active_insn (next) | |
3063 | && no_labels_between_p (insn, next)) | |
3064 | { | |
3065 | rtx label = JUMP_LABEL (next); | |
3066 | ||
3067 | /* Be careful how we do this to avoid deleting code or | |
3068 | labels that are momentarily dead. See similar optimization | |
3069 | in jump.c. | |
3070 | ||
3071 | We also need to ensure we properly handle the case when | |
3072 | invert_jump fails. */ | |
3073 | ||
3074 | ++LABEL_NUSES (target_label); | |
3075 | if (label) | |
3076 | ++LABEL_NUSES (label); | |
3077 | ||
3078 | if (invert_jump (insn, label)) | |
3079 | { | |
3080 | delete_insn (next); | |
3081 | next = insn; | |
3082 | } | |
3083 | ||
3084 | if (label) | |
3085 | --LABEL_NUSES (label); | |
3086 | ||
3087 | if (--LABEL_NUSES (target_label) == 0) | |
3088 | delete_insn (target_label); | |
3089 | ||
3090 | continue; | |
3091 | } | |
3092 | } | |
3093 | ||
3094 | /* If this is an unconditional jump and the previous insn is a | |
3095 | conditional jump, try reversing the condition of the previous | |
3096 | insn and swapping our targets. The next pass might be able to | |
3097 | fill the slots. | |
3098 | ||
3099 | Don't do this if we expect the conditional branch to be true, because | |
3100 | we would then be making the more common case longer. */ | |
3101 | ||
3102 | if (GET_CODE (insn) == JUMP_INSN | |
3103 | && (simplejump_p (insn) || GET_CODE (PATTERN (insn)) == RETURN) | |
3104 | && (other = prev_active_insn (insn)) != 0 | |
3480bb98 | 3105 | && (condjump_p (other) || condjump_in_parallel_p (other)) |
9c7e2978 | 3106 | && no_labels_between_p (other, insn) |
6f20793d | 3107 | && 0 > mostly_true_jump (other, |
0275a51b RK |
3108 | get_branch_condition (other, |
3109 | JUMP_LABEL (other)))) | |
9c7e2978 RK |
3110 | { |
3111 | rtx other_target = JUMP_LABEL (other); | |
7ca4e06e | 3112 | target_label = JUMP_LABEL (insn); |
9c7e2978 RK |
3113 | |
3114 | /* Increment the count of OTHER_TARGET, so it doesn't get deleted | |
3115 | as we move the label. */ | |
3116 | if (other_target) | |
3117 | ++LABEL_NUSES (other_target); | |
3118 | ||
3119 | if (invert_jump (other, target_label)) | |
326f06f7 | 3120 | reorg_redirect_jump (insn, other_target); |
9c7e2978 RK |
3121 | |
3122 | if (other_target) | |
3123 | --LABEL_NUSES (other_target); | |
3124 | } | |
3125 | ||
3126 | /* Now look only at cases where we have filled a delay slot. */ | |
3127 | if (GET_CODE (insn) != INSN | |
3128 | || GET_CODE (PATTERN (insn)) != SEQUENCE) | |
3129 | continue; | |
3130 | ||
3131 | pat = PATTERN (insn); | |
3132 | delay_insn = XVECEXP (pat, 0, 0); | |
3133 | ||
3134 | /* See if the first insn in the delay slot is redundant with some | |
3135 | previous insn. Remove it from the delay slot if so; then set up | |
3136 | to reprocess this insn. */ | |
f898abd7 | 3137 | if (redundant_insn (XVECEXP (pat, 0, 1), delay_insn, 0)) |
9c7e2978 RK |
3138 | { |
3139 | delete_from_delay_slot (XVECEXP (pat, 0, 1)); | |
3140 | next = prev_active_insn (next); | |
3141 | continue; | |
3142 | } | |
3143 | ||
9f5a2691 JL |
3144 | /* See if we have a RETURN insn with a filled delay slot followed |
3145 | by a RETURN insn with an unfilled a delay slot. If so, we can delete | |
3146 | the first RETURN (but not it's delay insn). This gives the same | |
3147 | effect in fewer instructions. | |
3148 | ||
3149 | Only do so if optimizing for size since this results in slower, but | |
3150 | smaller code. */ | |
3151 | if (optimize_size | |
3152 | && GET_CODE (PATTERN (delay_insn)) == RETURN | |
3153 | && next | |
3154 | && GET_CODE (next) == JUMP_INSN | |
3155 | && GET_CODE (PATTERN (next)) == RETURN) | |
3156 | { | |
3157 | int i; | |
3158 | ||
3159 | /* Delete the RETURN and just execute the delay list insns. | |
3160 | ||
3161 | We do this by deleting the INSN containing the SEQUENCE, then | |
3162 | re-emitting the insns separately, and then deleting the RETURN. | |
3163 | This allows the count of the jump target to be properly | |
3164 | decremented. */ | |
3165 | ||
3166 | /* Clear the from target bit, since these insns are no longer | |
3167 | in delay slots. */ | |
3168 | for (i = 0; i < XVECLEN (pat, 0); i++) | |
3169 | INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)) = 0; | |
3170 | ||
3171 | trial = PREV_INSN (insn); | |
3172 | delete_insn (insn); | |
3173 | emit_insn_after (pat, trial); | |
3174 | delete_scheduled_jump (delay_insn); | |
3175 | continue; | |
3176 | } | |
3177 | ||
9c7e2978 RK |
3178 | /* Now look only at the cases where we have a filled JUMP_INSN. */ |
3179 | if (GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) != JUMP_INSN | |
3480bb98 JL |
3180 | || ! (condjump_p (XVECEXP (PATTERN (insn), 0, 0)) |
3181 | || condjump_in_parallel_p (XVECEXP (PATTERN (insn), 0, 0)))) | |
9c7e2978 RK |
3182 | continue; |
3183 | ||
3184 | target_label = JUMP_LABEL (delay_insn); | |
3185 | ||
3186 | if (target_label) | |
3187 | { | |
3188 | /* If this jump goes to another unconditional jump, thread it, but | |
3189 | don't convert a jump into a RETURN here. */ | |
22422dbf | 3190 | trial = follow_jumps (target_label); |
9e94dc88 JW |
3191 | /* We use next_real_insn instead of next_active_insn, so that |
3192 | the special USE insns emitted by reorg won't be ignored. | |
3193 | If they are ignored, then they will get deleted if target_label | |
3194 | is now unreachable, and that would cause mark_target_live_regs | |
3195 | to fail. */ | |
3196 | trial = prev_label (next_real_insn (trial)); | |
9c7e2978 RK |
3197 | if (trial == 0 && target_label != 0) |
3198 | trial = find_end_label (); | |
3199 | ||
83fd5651 JL |
3200 | if (trial != target_label |
3201 | && redirect_with_delay_slots_safe_p (delay_insn, trial, insn)) | |
9c7e2978 | 3202 | { |
326f06f7 | 3203 | reorg_redirect_jump (delay_insn, trial); |
9c7e2978 RK |
3204 | target_label = trial; |
3205 | } | |
3206 | ||
3207 | /* If the first insn at TARGET_LABEL is redundant with a previous | |
3208 | insn, redirect the jump to the following insn process again. */ | |
3209 | trial = next_active_insn (target_label); | |
3210 | if (trial && GET_CODE (PATTERN (trial)) != SEQUENCE | |
f898abd7 | 3211 | && redundant_insn (trial, insn, 0)) |
9c7e2978 | 3212 | { |
eed04dff JL |
3213 | rtx tmp; |
3214 | ||
3215 | /* Figure out where to emit the special USE insn so we don't | |
3216 | later incorrectly compute register live/death info. */ | |
3217 | tmp = next_active_insn (trial); | |
3218 | if (tmp == 0) | |
3219 | tmp = find_end_label (); | |
3220 | ||
3221 | /* Insert the special USE insn and update dataflow info. */ | |
3222 | update_block (trial, tmp); | |
3223 | ||
3224 | /* Now emit a label before the special USE insn, and | |
3225 | redirect our jump to the new label. */ | |
3226 | target_label = get_label_before (PREV_INSN (tmp)); | |
326f06f7 | 3227 | reorg_redirect_jump (delay_insn, target_label); |
9c7e2978 RK |
3228 | next = insn; |
3229 | continue; | |
3230 | } | |
3231 | ||
3232 | /* Similarly, if it is an unconditional jump with one insn in its | |
3233 | delay list and that insn is redundant, thread the jump. */ | |
3234 | if (trial && GET_CODE (PATTERN (trial)) == SEQUENCE | |
3235 | && XVECLEN (PATTERN (trial), 0) == 2 | |
3236 | && GET_CODE (XVECEXP (PATTERN (trial), 0, 0)) == JUMP_INSN | |
3237 | && (simplejump_p (XVECEXP (PATTERN (trial), 0, 0)) | |
3238 | || GET_CODE (PATTERN (XVECEXP (PATTERN (trial), 0, 0))) == RETURN) | |
f898abd7 | 3239 | && redundant_insn (XVECEXP (PATTERN (trial), 0, 1), insn, 0)) |
9c7e2978 RK |
3240 | { |
3241 | target_label = JUMP_LABEL (XVECEXP (PATTERN (trial), 0, 0)); | |
3242 | if (target_label == 0) | |
3243 | target_label = find_end_label (); | |
83fd5651 JL |
3244 | |
3245 | if (redirect_with_delay_slots_safe_p (delay_insn, target_label, | |
3246 | insn)) | |
3247 | { | |
3248 | reorg_redirect_jump (delay_insn, target_label); | |
3249 | next = insn; | |
3250 | continue; | |
3251 | } | |
9c7e2978 RK |
3252 | } |
3253 | } | |
3254 | ||
3255 | if (! INSN_ANNULLED_BRANCH_P (delay_insn) | |
3256 | && prev_active_insn (target_label) == insn | |
3480bb98 | 3257 | && ! condjump_in_parallel_p (delay_insn) |
9c7e2978 RK |
3258 | #ifdef HAVE_cc0 |
3259 | /* If the last insn in the delay slot sets CC0 for some insn, | |
3260 | various code assumes that it is in a delay slot. We could | |
3261 | put it back where it belonged and delete the register notes, | |
6dc42e49 | 3262 | but it doesn't seem worthwhile in this uncommon case. */ |
9c7e2978 | 3263 | && ! find_reg_note (XVECEXP (pat, 0, XVECLEN (pat, 0) - 1), |
fb3821f7 | 3264 | REG_CC_USER, NULL_RTX) |
9c7e2978 RK |
3265 | #endif |
3266 | ) | |
3267 | { | |
ac224823 RK |
3268 | int i; |
3269 | ||
9c7e2978 RK |
3270 | /* All this insn does is execute its delay list and jump to the |
3271 | following insn. So delete the jump and just execute the delay | |
3272 | list insns. | |
3273 | ||
3274 | We do this by deleting the INSN containing the SEQUENCE, then | |
3275 | re-emitting the insns separately, and then deleting the jump. | |
3276 | This allows the count of the jump target to be properly | |
3277 | decremented. */ | |
3278 | ||
ac224823 RK |
3279 | /* Clear the from target bit, since these insns are no longer |
3280 | in delay slots. */ | |
3281 | for (i = 0; i < XVECLEN (pat, 0); i++) | |
3282 | INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)) = 0; | |
3283 | ||
9c7e2978 RK |
3284 | trial = PREV_INSN (insn); |
3285 | delete_insn (insn); | |
3286 | emit_insn_after (pat, trial); | |
3287 | delete_scheduled_jump (delay_insn); | |
3288 | continue; | |
3289 | } | |
3290 | ||
51ec2375 JW |
3291 | /* See if this is an unconditional jump around a single insn which is |
3292 | identical to the one in its delay slot. In this case, we can just | |
3293 | delete the branch and the insn in its delay slot. */ | |
3294 | if (next && GET_CODE (next) == INSN | |
3295 | && prev_label (next_active_insn (next)) == target_label | |
3296 | && simplejump_p (insn) | |
3297 | && XVECLEN (pat, 0) == 2 | |
3298 | && rtx_equal_p (PATTERN (next), PATTERN (XVECEXP (pat, 0, 1)))) | |
3299 | { | |
3300 | delete_insn (insn); | |
3301 | continue; | |
3302 | } | |
3303 | ||
9c7e2978 RK |
3304 | /* See if this jump (with its delay slots) branches around another |
3305 | jump (without delay slots). If so, invert this jump and point | |
3306 | it to the target of the second jump. We cannot do this for | |
3307 | annulled jumps, though. Again, don't convert a jump to a RETURN | |
3308 | here. */ | |
3309 | if (! INSN_ANNULLED_BRANCH_P (delay_insn) | |
3310 | && next && GET_CODE (next) == JUMP_INSN | |
3311 | && (simplejump_p (next) || GET_CODE (PATTERN (next)) == RETURN) | |
3312 | && next_active_insn (target_label) == next_active_insn (next) | |
3313 | && no_labels_between_p (insn, next)) | |
3314 | { | |
3315 | rtx label = JUMP_LABEL (next); | |
3316 | rtx old_label = JUMP_LABEL (delay_insn); | |
3317 | ||
3318 | if (label == 0) | |
3319 | label = find_end_label (); | |
3320 | ||
83fd5651 | 3321 | if (redirect_with_delay_slots_safe_p (delay_insn, label, insn)) |
9c7e2978 | 3322 | { |
83fd5651 JL |
3323 | /* Be careful how we do this to avoid deleting code or labels |
3324 | that are momentarily dead. See similar optimization in | |
3325 | jump.c */ | |
3326 | if (old_label) | |
3327 | ++LABEL_NUSES (old_label); | |
9c7e2978 | 3328 | |
83fd5651 JL |
3329 | if (invert_jump (delay_insn, label)) |
3330 | { | |
9e8b2461 RK |
3331 | int i; |
3332 | ||
3333 | /* Must update the INSN_FROM_TARGET_P bits now that | |
3334 | the branch is reversed, so that mark_target_live_regs | |
3335 | will handle the delay slot insn correctly. */ | |
3336 | for (i = 1; i < XVECLEN (PATTERN (insn), 0); i++) | |
3337 | { | |
3338 | rtx slot = XVECEXP (PATTERN (insn), 0, i); | |
3339 | INSN_FROM_TARGET_P (slot) = ! INSN_FROM_TARGET_P (slot); | |
3340 | } | |
3341 | ||
83fd5651 JL |
3342 | delete_insn (next); |
3343 | next = insn; | |
3344 | } | |
3345 | ||
3346 | if (old_label && --LABEL_NUSES (old_label) == 0) | |
3347 | delete_insn (old_label); | |
3348 | continue; | |
3349 | } | |
9c7e2978 RK |
3350 | } |
3351 | ||
3352 | /* If we own the thread opposite the way this insn branches, see if we | |
3353 | can merge its delay slots with following insns. */ | |
3354 | if (INSN_FROM_TARGET_P (XVECEXP (pat, 0, 1)) | |
3355 | && own_thread_p (NEXT_INSN (insn), 0, 1)) | |
3356 | try_merge_delay_insns (insn, next); | |
3357 | else if (! INSN_FROM_TARGET_P (XVECEXP (pat, 0, 1)) | |
3358 | && own_thread_p (target_label, target_label, 0)) | |
3359 | try_merge_delay_insns (insn, next_active_insn (target_label)); | |
3360 | ||
3361 | /* If we get here, we haven't deleted INSN. But we may have deleted | |
3362 | NEXT, so recompute it. */ | |
3363 | next = next_active_insn (insn); | |
3364 | } | |
3365 | } | |
3366 | \f | |
3367 | #ifdef HAVE_return | |
3368 | ||
3369 | /* Look for filled jumps to the end of function label. We can try to convert | |
3370 | them into RETURN insns if the insns in the delay slot are valid for the | |
3371 | RETURN as well. */ | |
3372 | ||
3373 | static void | |
3374 | make_return_insns (first) | |
3375 | rtx first; | |
3376 | { | |
3377 | rtx insn, jump_insn, pat; | |
3378 | rtx real_return_label = end_of_function_label; | |
3379 | int slots, i; | |
3380 | ||
3381 | /* See if there is a RETURN insn in the function other than the one we | |
3382 | made for END_OF_FUNCTION_LABEL. If so, set up anything we can't change | |
3383 | into a RETURN to jump to it. */ | |
3384 | for (insn = first; insn; insn = NEXT_INSN (insn)) | |
3385 | if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == RETURN) | |
3386 | { | |
3387 | real_return_label = get_label_before (insn); | |
3388 | break; | |
3389 | } | |
3390 | ||
3391 | /* Show an extra usage of REAL_RETURN_LABEL so it won't go away if it | |
3392 | was equal to END_OF_FUNCTION_LABEL. */ | |
3393 | LABEL_NUSES (real_return_label)++; | |
3394 | ||
3395 | /* Clear the list of insns to fill so we can use it. */ | |
3396 | obstack_free (&unfilled_slots_obstack, unfilled_firstobj); | |
3397 | ||
3398 | for (insn = first; insn; insn = NEXT_INSN (insn)) | |
3399 | { | |
35523fce JL |
3400 | int flags; |
3401 | ||
9c7e2978 RK |
3402 | /* Only look at filled JUMP_INSNs that go to the end of function |
3403 | label. */ | |
3404 | if (GET_CODE (insn) != INSN | |
3405 | || GET_CODE (PATTERN (insn)) != SEQUENCE | |
3406 | || GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) != JUMP_INSN | |
3407 | || JUMP_LABEL (XVECEXP (PATTERN (insn), 0, 0)) != end_of_function_label) | |
3408 | continue; | |
3409 | ||
3410 | pat = PATTERN (insn); | |
3411 | jump_insn = XVECEXP (pat, 0, 0); | |
3412 | ||
18beb3e9 | 3413 | /* If we can't make the jump into a RETURN, try to redirect it to the best |
9c7e2978 | 3414 | RETURN and go on to the next insn. */ |
326f06f7 | 3415 | if (! reorg_redirect_jump (jump_insn, NULL_RTX)) |
9c7e2978 | 3416 | { |
18beb3e9 JL |
3417 | /* Make sure redirecting the jump will not invalidate the delay |
3418 | slot insns. */ | |
3419 | if (redirect_with_delay_slots_safe_p (jump_insn, | |
3420 | real_return_label, | |
3421 | insn)) | |
3422 | reorg_redirect_jump (jump_insn, real_return_label); | |
9c7e2978 RK |
3423 | continue; |
3424 | } | |
3425 | ||
3426 | /* See if this RETURN can accept the insns current in its delay slot. | |
3427 | It can if it has more or an equal number of slots and the contents | |
3428 | of each is valid. */ | |
3429 | ||
35523fce | 3430 | flags = get_jump_flags (jump_insn, JUMP_LABEL (jump_insn)); |
9c7e2978 RK |
3431 | slots = num_delay_slots (jump_insn); |
3432 | if (slots >= XVECLEN (pat, 0) - 1) | |
3433 | { | |
3434 | for (i = 1; i < XVECLEN (pat, 0); i++) | |
3435 | if (! ( | |
3436 | #ifdef ANNUL_IFFALSE_SLOTS | |
3437 | (INSN_ANNULLED_BRANCH_P (jump_insn) | |
3438 | && INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) | |
3439 | ? eligible_for_annul_false (jump_insn, i - 1, | |
35523fce | 3440 | XVECEXP (pat, 0, i), flags) : |
9c7e2978 RK |
3441 | #endif |
3442 | #ifdef ANNUL_IFTRUE_SLOTS | |
3443 | (INSN_ANNULLED_BRANCH_P (jump_insn) | |
3444 | && ! INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) | |
3445 | ? eligible_for_annul_true (jump_insn, i - 1, | |
35523fce | 3446 | XVECEXP (pat, 0, i), flags) : |
9c7e2978 | 3447 | #endif |
35523fce | 3448 | eligible_for_delay (jump_insn, i -1, XVECEXP (pat, 0, i), flags))) |
9c7e2978 RK |
3449 | break; |
3450 | } | |
3451 | else | |
3452 | i = 0; | |
3453 | ||
3454 | if (i == XVECLEN (pat, 0)) | |
3455 | continue; | |
3456 | ||
3457 | /* We have to do something with this insn. If it is an unconditional | |
3458 | RETURN, delete the SEQUENCE and output the individual insns, | |
3459 | followed by the RETURN. Then set things up so we try to find | |
3460 | insns for its delay slots, if it needs some. */ | |
3461 | if (GET_CODE (PATTERN (jump_insn)) == RETURN) | |
3462 | { | |
3463 | rtx prev = PREV_INSN (insn); | |
3464 | ||
3465 | delete_insn (insn); | |
3466 | for (i = 1; i < XVECLEN (pat, 0); i++) | |
3467 | prev = emit_insn_after (PATTERN (XVECEXP (pat, 0, i)), prev); | |
3468 | ||
3469 | insn = emit_jump_insn_after (PATTERN (jump_insn), prev); | |
3470 | emit_barrier_after (insn); | |
3471 | ||
3472 | if (slots) | |
3473 | obstack_ptr_grow (&unfilled_slots_obstack, insn); | |
3474 | } | |
3475 | else | |
3476 | /* It is probably more efficient to keep this with its current | |
3477 | delay slot as a branch to a RETURN. */ | |
326f06f7 | 3478 | reorg_redirect_jump (jump_insn, real_return_label); |
9c7e2978 RK |
3479 | } |
3480 | ||
3481 | /* Now delete REAL_RETURN_LABEL if we never used it. Then try to fill any | |
3482 | new delay slots we have created. */ | |
3483 | if (--LABEL_NUSES (real_return_label) == 0) | |
3484 | delete_insn (real_return_label); | |
3485 | ||
91a51951 KG |
3486 | fill_simple_delay_slots (1); |
3487 | fill_simple_delay_slots (0); | |
9c7e2978 RK |
3488 | } |
3489 | #endif | |
3490 | \f | |
3491 | /* Try to find insns to place in delay slots. */ | |
3492 | ||
3493 | void | |
3494 | dbr_schedule (first, file) | |
3495 | rtx first; | |
3496 | FILE *file; | |
3497 | { | |
7bd80f37 | 3498 | rtx insn, next, epilogue_insn = 0; |
9c7e2978 RK |
3499 | int i; |
3500 | #if 0 | |
3501 | int old_flag_no_peephole = flag_no_peephole; | |
3502 | ||
3503 | /* Execute `final' once in prescan mode to delete any insns that won't be | |
3504 | used. Don't let final try to do any peephole optimization--it will | |
3505 | ruin dataflow information for this pass. */ | |
3506 | ||
3507 | flag_no_peephole = 1; | |
3508 | final (first, 0, NO_DEBUG, 1, 1); | |
3509 | flag_no_peephole = old_flag_no_peephole; | |
3510 | #endif | |
3511 | ||
c3b80729 JL |
3512 | /* If the current function has no insns other than the prologue and |
3513 | epilogue, then do not try to fill any delay slots. */ | |
3514 | if (n_basic_blocks == 0) | |
3515 | return; | |
3516 | ||
9c7e2978 RK |
3517 | /* Find the highest INSN_UID and allocate and initialize our map from |
3518 | INSN_UID's to position in code. */ | |
3519 | for (max_uid = 0, insn = first; insn; insn = NEXT_INSN (insn)) | |
7bd80f37 TW |
3520 | { |
3521 | if (INSN_UID (insn) > max_uid) | |
3522 | max_uid = INSN_UID (insn); | |
3523 | if (GET_CODE (insn) == NOTE | |
3524 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EPILOGUE_BEG) | |
3525 | epilogue_insn = insn; | |
3526 | } | |
9c7e2978 | 3527 | |
2a92c071 | 3528 | uid_to_ruid = (int *) alloca ((max_uid + 1) * sizeof (int)); |
9c7e2978 RK |
3529 | for (i = 0, insn = first; insn; i++, insn = NEXT_INSN (insn)) |
3530 | uid_to_ruid[INSN_UID (insn)] = i; | |
3531 | ||
3532 | /* Initialize the list of insns that need filling. */ | |
3533 | if (unfilled_firstobj == 0) | |
3534 | { | |
3535 | gcc_obstack_init (&unfilled_slots_obstack); | |
3536 | unfilled_firstobj = (rtx *) obstack_alloc (&unfilled_slots_obstack, 0); | |
3537 | } | |
3538 | ||
3539 | for (insn = next_active_insn (first); insn; insn = next_active_insn (insn)) | |
3540 | { | |
3541 | rtx target; | |
3542 | ||
3543 | INSN_ANNULLED_BRANCH_P (insn) = 0; | |
3544 | INSN_FROM_TARGET_P (insn) = 0; | |
3545 | ||
3546 | /* Skip vector tables. We can't get attributes for them. */ | |
3547 | if (GET_CODE (insn) == JUMP_INSN | |
3548 | && (GET_CODE (PATTERN (insn)) == ADDR_VEC | |
3549 | || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)) | |
3550 | continue; | |
3551 | ||
3552 | if (num_delay_slots (insn) > 0) | |
3553 | obstack_ptr_grow (&unfilled_slots_obstack, insn); | |
3554 | ||
3555 | /* Ensure all jumps go to the last of a set of consecutive labels. */ | |
3480bb98 JL |
3556 | if (GET_CODE (insn) == JUMP_INSN |
3557 | && (condjump_p (insn) || condjump_in_parallel_p (insn)) | |
9c7e2978 RK |
3558 | && JUMP_LABEL (insn) != 0 |
3559 | && ((target = prev_label (next_active_insn (JUMP_LABEL (insn)))) | |
3560 | != JUMP_LABEL (insn))) | |
3561 | redirect_jump (insn, target); | |
3562 | } | |
3563 | ||
ca545bb5 | 3564 | init_resource_info (epilogue_insn); |
7bd80f37 | 3565 | |
9c7e2978 RK |
3566 | /* Show we haven't computed an end-of-function label yet. */ |
3567 | end_of_function_label = 0; | |
3568 | ||
9c7e2978 | 3569 | /* Initialize the statistics for this function. */ |
780c3483 RK |
3570 | bzero ((char *) num_insns_needing_delays, sizeof num_insns_needing_delays); |
3571 | bzero ((char *) num_filled_delays, sizeof num_filled_delays); | |
9c7e2978 RK |
3572 | |
3573 | /* Now do the delay slot filling. Try everything twice in case earlier | |
3574 | changes make more slots fillable. */ | |
3575 | ||
3576 | for (reorg_pass_number = 0; | |
3577 | reorg_pass_number < MAX_REORG_PASSES; | |
3578 | reorg_pass_number++) | |
3579 | { | |
91a51951 KG |
3580 | fill_simple_delay_slots (1); |
3581 | fill_simple_delay_slots (0); | |
3582 | fill_eager_delay_slots (); | |
9c7e2978 RK |
3583 | relax_delay_slots (first); |
3584 | } | |
3585 | ||
3586 | /* Delete any USE insns made by update_block; subsequent passes don't need | |
3587 | them or know how to deal with them. */ | |
3588 | for (insn = first; insn; insn = next) | |
3589 | { | |
3590 | next = NEXT_INSN (insn); | |
3591 | ||
3592 | if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == USE | |
1422dce0 | 3593 | && GET_RTX_CLASS (GET_CODE (XEXP (PATTERN (insn), 0))) == 'i') |
9c7e2978 RK |
3594 | next = delete_insn (insn); |
3595 | } | |
3596 | ||
3597 | /* If we made an end of function label, indicate that it is now | |
3598 | safe to delete it by undoing our prior adjustment to LABEL_NUSES. | |
3599 | If it is now unused, delete it. */ | |
3600 | if (end_of_function_label && --LABEL_NUSES (end_of_function_label) == 0) | |
3601 | delete_insn (end_of_function_label); | |
3602 | ||
3603 | #ifdef HAVE_return | |
3604 | if (HAVE_return && end_of_function_label != 0) | |
3605 | make_return_insns (first); | |
3606 | #endif | |
3607 | ||
3608 | obstack_free (&unfilled_slots_obstack, unfilled_firstobj); | |
3609 | ||
3610 | /* It is not clear why the line below is needed, but it does seem to be. */ | |
3611 | unfilled_firstobj = (rtx *) obstack_alloc (&unfilled_slots_obstack, 0); | |
3612 | ||
bdac5f58 TW |
3613 | /* Reposition the prologue and epilogue notes in case we moved the |
3614 | prologue/epilogue insns. */ | |
3615 | reposition_prologue_and_epilogue_notes (first); | |
3616 | ||
9c7e2978 RK |
3617 | if (file) |
3618 | { | |
3619 | register int i, j, need_comma; | |
3620 | ||
3621 | for (reorg_pass_number = 0; | |
3622 | reorg_pass_number < MAX_REORG_PASSES; | |
3623 | reorg_pass_number++) | |
3624 | { | |
3625 | fprintf (file, ";; Reorg pass #%d:\n", reorg_pass_number + 1); | |
3626 | for (i = 0; i < NUM_REORG_FUNCTIONS; i++) | |
3627 | { | |
3628 | need_comma = 0; | |
3629 | fprintf (file, ";; Reorg function #%d\n", i); | |
3630 | ||
3631 | fprintf (file, ";; %d insns needing delay slots\n;; ", | |
3632 | num_insns_needing_delays[i][reorg_pass_number]); | |
3633 | ||
3634 | for (j = 0; j < MAX_DELAY_HISTOGRAM; j++) | |
3635 | if (num_filled_delays[i][j][reorg_pass_number]) | |
3636 | { | |
3637 | if (need_comma) | |
3638 | fprintf (file, ", "); | |
3639 | need_comma = 1; | |
3640 | fprintf (file, "%d got %d delays", | |
3641 | num_filled_delays[i][j][reorg_pass_number], j); | |
3642 | } | |
3643 | fprintf (file, "\n"); | |
3644 | } | |
3645 | } | |
3646 | } | |
c107334d DM |
3647 | |
3648 | /* For all JUMP insns, fill in branch prediction notes, so that during | |
3649 | assembler output a target can set branch prediction bits in the code. | |
3650 | We have to do this now, as up until this point the destinations of | |
3651 | JUMPS can be moved around and changed, but past right here that cannot | |
3652 | happen. */ | |
3653 | for (insn = first; insn; insn = NEXT_INSN (insn)) | |
3654 | { | |
3655 | int pred_flags; | |
3656 | ||
e0d80184 DM |
3657 | if (GET_CODE (insn) == INSN) |
3658 | { | |
3659 | rtx pat = PATTERN (insn); | |
3660 | ||
3661 | if (GET_CODE (pat) == SEQUENCE) | |
3662 | insn = XVECEXP (pat, 0, 0); | |
3663 | } | |
c107334d DM |
3664 | if (GET_CODE (insn) != JUMP_INSN) |
3665 | continue; | |
3666 | ||
3667 | pred_flags = get_jump_flags (insn, JUMP_LABEL (insn)); | |
38a448ca RH |
3668 | REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_BR_PRED, |
3669 | GEN_INT (pred_flags), | |
3670 | REG_NOTES (insn)); | |
c107334d | 3671 | } |
ca545bb5 | 3672 | free_resource_info (); |
9c7e2978 RK |
3673 | } |
3674 | #endif /* DELAY_SLOTS */ |