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9c7e2978 | 1 | /* Perform instruction reorganizations for delay slot filling. |
175a444d | 2 | Copyright (C) 1992, 1993, 1994, 1995 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 | |
20 | the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
21 | ||
9c7e2978 RK |
22 | /* Instruction reorganization pass. |
23 | ||
24 | This pass runs after register allocation and final jump | |
25 | optimization. It should be the last pass to run before peephole. | |
26 | It serves primarily to fill delay slots of insns, typically branch | |
27 | and call insns. Other insns typically involve more complicated | |
6dc42e49 | 28 | interactions of data dependencies and resource constraints, and |
9c7e2978 RK |
29 | are better handled by scheduling before register allocation (by the |
30 | function `schedule_insns'). | |
31 | ||
32 | The Branch Penalty is the number of extra cycles that are needed to | |
33 | execute a branch insn. On an ideal machine, branches take a single | |
34 | cycle, and the Branch Penalty is 0. Several RISC machines approach | |
35 | branch delays differently: | |
36 | ||
37 | The MIPS and AMD 29000 have a single branch delay slot. Most insns | |
38 | (except other branches) can be used to fill this slot. When the | |
39 | slot is filled, two insns execute in two cycles, reducing the | |
40 | branch penalty to zero. | |
41 | ||
42 | The Motorola 88000 conditionally exposes its branch delay slot, | |
43 | so code is shorter when it is turned off, but will run faster | |
44 | when useful insns are scheduled there. | |
45 | ||
46 | The IBM ROMP has two forms of branch and call insns, both with and | |
47 | without a delay slot. Much like the 88k, insns not using the delay | |
48 | slot can be shorted (2 bytes vs. 4 bytes), but will run slowed. | |
49 | ||
50 | The SPARC always has a branch delay slot, but its effects can be | |
51 | annulled when the branch is not taken. This means that failing to | |
52 | find other sources of insns, we can hoist an insn from the branch | |
53 | target that would only be safe to execute knowing that the branch | |
54 | is taken. | |
55 | ||
35523fce JL |
56 | The HP-PA always has a branch delay slot. For unconditional branches |
57 | its effects can be annulled when the branch is taken. The effects | |
58 | of the delay slot in a conditional branch can be nullified for forward | |
59 | taken branches, or for untaken backward branches. This means | |
60 | we can hoist insns from the fall-through path for forward branches or | |
61 | steal insns from the target of backward branches. | |
62 | ||
9c7e2978 RK |
63 | Three techniques for filling delay slots have been implemented so far: |
64 | ||
65 | (1) `fill_simple_delay_slots' is the simplest, most efficient way | |
66 | to fill delay slots. This pass first looks for insns which come | |
67 | from before the branch and which are safe to execute after the | |
68 | branch. Then it searches after the insn requiring delay slots or, | |
69 | in the case of a branch, for insns that are after the point at | |
70 | which the branch merges into the fallthrough code, if such a point | |
71 | exists. When such insns are found, the branch penalty decreases | |
72 | and no code expansion takes place. | |
73 | ||
74 | (2) `fill_eager_delay_slots' is more complicated: it is used for | |
75 | scheduling conditional jumps, or for scheduling jumps which cannot | |
76 | be filled using (1). A machine need not have annulled jumps to use | |
77 | this strategy, but it helps (by keeping more options open). | |
78 | `fill_eager_delay_slots' tries to guess the direction the branch | |
79 | will go; if it guesses right 100% of the time, it can reduce the | |
c0e12601 | 80 | branch penalty as much as `fill_simple_delay_slots' does. If it |
9c7e2978 RK |
81 | guesses wrong 100% of the time, it might as well schedule nops (or |
82 | on the m88k, unexpose the branch slot). When | |
83 | `fill_eager_delay_slots' takes insns from the fall-through path of | |
84 | the jump, usually there is no code expansion; when it takes insns | |
85 | from the branch target, there is code expansion if it is not the | |
86 | only way to reach that target. | |
87 | ||
88 | (3) `relax_delay_slots' uses a set of rules to simplify code that | |
89 | has been reorganized by (1) and (2). It finds cases where | |
90 | conditional test can be eliminated, jumps can be threaded, extra | |
91 | insns can be eliminated, etc. It is the job of (1) and (2) to do a | |
92 | good job of scheduling locally; `relax_delay_slots' takes care of | |
93 | making the various individual schedules work well together. It is | |
94 | especially tuned to handle the control flow interactions of branch | |
95 | insns. It does nothing for insns with delay slots that do not | |
96 | branch. | |
97 | ||
98 | On machines that use CC0, we are very conservative. We will not make | |
99 | a copy of an insn involving CC0 since we want to maintain a 1-1 | |
d45cf215 | 100 | correspondence between the insn that sets and uses CC0. The insns are |
9c7e2978 RK |
101 | allowed to be separated by placing an insn that sets CC0 (but not an insn |
102 | that uses CC0; we could do this, but it doesn't seem worthwhile) in a | |
103 | delay slot. In that case, we point each insn at the other with REG_CC_USER | |
104 | and REG_CC_SETTER notes. Note that these restrictions affect very few | |
105 | machines because most RISC machines with delay slots will not use CC0 | |
106 | (the RT is the only known exception at this point). | |
107 | ||
108 | Not yet implemented: | |
109 | ||
110 | The Acorn Risc Machine can conditionally execute most insns, so | |
111 | it is profitable to move single insns into a position to execute | |
112 | based on the condition code of the previous insn. | |
113 | ||
114 | The HP-PA can conditionally nullify insns, providing a similar | |
115 | effect to the ARM, differing mostly in which insn is "in charge". */ | |
116 | ||
117 | #include <stdio.h> | |
118 | #include "config.h" | |
119 | #include "rtl.h" | |
120 | #include "insn-config.h" | |
121 | #include "conditions.h" | |
122 | #include "hard-reg-set.h" | |
123 | #include "basic-block.h" | |
124 | #include "regs.h" | |
125 | #include "insn-flags.h" | |
126 | #include "recog.h" | |
127 | #include "flags.h" | |
128 | #include "output.h" | |
129 | #include "obstack.h" | |
d80e9fd7 RS |
130 | #include "insn-attr.h" |
131 | ||
132 | #ifdef DELAY_SLOTS | |
9c7e2978 RK |
133 | |
134 | #define obstack_chunk_alloc xmalloc | |
135 | #define obstack_chunk_free free | |
136 | ||
9c7e2978 | 137 | #ifndef ANNUL_IFTRUE_SLOTS |
35523fce | 138 | #define eligible_for_annul_true(INSN, SLOTS, TRIAL, FLAGS) 0 |
9c7e2978 RK |
139 | #endif |
140 | #ifndef ANNUL_IFFALSE_SLOTS | |
35523fce | 141 | #define eligible_for_annul_false(INSN, SLOTS, TRIAL, FLAGS) 0 |
9c7e2978 RK |
142 | #endif |
143 | ||
144 | /* Insns which have delay slots that have not yet been filled. */ | |
145 | ||
146 | static struct obstack unfilled_slots_obstack; | |
147 | static rtx *unfilled_firstobj; | |
148 | ||
149 | /* Define macros to refer to the first and last slot containing unfilled | |
150 | insns. These are used because the list may move and its address | |
151 | should be recomputed at each use. */ | |
152 | ||
153 | #define unfilled_slots_base \ | |
154 | ((rtx *) obstack_base (&unfilled_slots_obstack)) | |
155 | ||
156 | #define unfilled_slots_next \ | |
157 | ((rtx *) obstack_next_free (&unfilled_slots_obstack)) | |
158 | ||
159 | /* This structure is used to indicate which hardware resources are set or | |
160 | needed by insns so far. */ | |
161 | ||
162 | struct resources | |
163 | { | |
164 | char memory; /* Insn sets or needs a memory location. */ | |
8eae5ed6 | 165 | char unch_memory; /* Insn sets of needs a "unchanging" MEM. */ |
9c7e2978 RK |
166 | char volatil; /* Insn sets or needs a volatile memory loc. */ |
167 | char cc; /* Insn sets or needs the condition codes. */ | |
168 | HARD_REG_SET regs; /* Which registers are set or needed. */ | |
169 | }; | |
170 | ||
171 | /* Macro to clear all resources. */ | |
172 | #define CLEAR_RESOURCE(RES) \ | |
8eae5ed6 | 173 | do { (RES)->memory = (RES)->unch_memory = (RES)->volatil = (RES)->cc = 0; \ |
9c7e2978 RK |
174 | CLEAR_HARD_REG_SET ((RES)->regs); } while (0) |
175 | ||
7bd80f37 TW |
176 | /* Indicates what resources are required at the beginning of the epilogue. */ |
177 | static struct resources start_of_epilogue_needs; | |
178 | ||
9c7e2978 RK |
179 | /* Indicates what resources are required at function end. */ |
180 | static struct resources end_of_function_needs; | |
181 | ||
182 | /* Points to the label before the end of the function. */ | |
183 | static rtx end_of_function_label; | |
184 | ||
6dc42e49 | 185 | /* This structure is used to record liveness information at the targets or |
9c7e2978 RK |
186 | fallthrough insns of branches. We will most likely need the information |
187 | at targets again, so save them in a hash table rather than recomputing them | |
188 | each time. */ | |
189 | ||
190 | struct target_info | |
191 | { | |
192 | int uid; /* INSN_UID of target. */ | |
193 | struct target_info *next; /* Next info for same hash bucket. */ | |
194 | HARD_REG_SET live_regs; /* Registers live at target. */ | |
195 | int block; /* Basic block number containing target. */ | |
196 | int bb_tick; /* Generation count of basic block info. */ | |
197 | }; | |
198 | ||
199 | #define TARGET_HASH_PRIME 257 | |
200 | ||
201 | /* Define the hash table itself. */ | |
202 | static struct target_info **target_hash_table; | |
203 | ||
204 | /* For each basic block, we maintain a generation number of its basic | |
205 | block info, which is updated each time we move an insn from the | |
206 | target of a jump. This is the generation number indexed by block | |
207 | number. */ | |
208 | ||
209 | static int *bb_ticks; | |
210 | ||
211 | /* Mapping between INSN_UID's and position in the code since INSN_UID's do | |
212 | not always monotonically increase. */ | |
213 | static int *uid_to_ruid; | |
214 | ||
215 | /* Highest valid index in `uid_to_ruid'. */ | |
216 | static int max_uid; | |
217 | ||
d8e8f346 RK |
218 | static void mark_referenced_resources PROTO((rtx, struct resources *, int)); |
219 | static void mark_set_resources PROTO((rtx, struct resources *, int, int)); | |
220 | static int stop_search_p PROTO((rtx, int)); | |
221 | static int resource_conflicts_p PROTO((struct resources *, | |
222 | struct resources *)); | |
223 | static int insn_references_resource_p PROTO((rtx, struct resources *, int)); | |
224 | static int insn_sets_resources_p PROTO((rtx, struct resources *, int)); | |
225 | static rtx find_end_label PROTO((void)); | |
226 | static rtx emit_delay_sequence PROTO((rtx, rtx, int, int)); | |
227 | static rtx add_to_delay_list PROTO((rtx, rtx)); | |
228 | static void delete_from_delay_slot PROTO((rtx)); | |
229 | static void delete_scheduled_jump PROTO((rtx)); | |
230 | static void note_delay_statistics PROTO((int, int)); | |
231 | static rtx optimize_skip PROTO((rtx)); | |
35523fce | 232 | static int get_jump_flags PROTO((rtx, rtx)); |
0275a51b | 233 | static int rare_destination PROTO((rtx)); |
d8e8f346 RK |
234 | static int mostly_true_jump PROTO((rtx, rtx)); |
235 | static rtx get_branch_condition PROTO((rtx, rtx)); | |
236 | static int condition_dominates_p PROTO((rtx, rtx)); | |
237 | static rtx steal_delay_list_from_target PROTO((rtx, rtx, rtx, rtx, | |
238 | struct resources *, | |
239 | struct resources *, | |
240 | struct resources *, | |
241 | int, int *, int *, rtx *)); | |
242 | static rtx steal_delay_list_from_fallthrough PROTO((rtx, rtx, rtx, rtx, | |
243 | struct resources *, | |
244 | struct resources *, | |
245 | struct resources *, | |
246 | int, int *, int *)); | |
247 | static void try_merge_delay_insns PROTO((rtx, rtx)); | |
f898abd7 | 248 | static rtx redundant_insn PROTO((rtx, rtx, rtx)); |
d8e8f346 RK |
249 | static int own_thread_p PROTO((rtx, rtx, int)); |
250 | static int find_basic_block PROTO((rtx)); | |
251 | static void update_block PROTO((rtx, rtx)); | |
326f06f7 | 252 | static int reorg_redirect_jump PROTO((rtx, rtx)); |
d8e8f346 | 253 | static void update_reg_dead_notes PROTO((rtx, rtx)); |
5317d2f8 | 254 | static void update_reg_unused_notes PROTO((rtx, rtx)); |
d8e8f346 RK |
255 | static void update_live_status PROTO((rtx, rtx)); |
256 | static rtx next_insn_no_annul PROTO((rtx)); | |
257 | static void mark_target_live_regs PROTO((rtx, struct resources *)); | |
258 | static void fill_simple_delay_slots PROTO((rtx, int)); | |
259 | static rtx fill_slots_from_thread PROTO((rtx, rtx, rtx, rtx, int, int, | |
260 | int, int, int, int *)); | |
261 | static void fill_eager_delay_slots PROTO((rtx)); | |
262 | static void relax_delay_slots PROTO((rtx)); | |
263 | static void make_return_insns PROTO((rtx)); | |
b304ad47 JL |
264 | static int redirect_with_delay_slots_safe_p PROTO ((rtx, rtx, rtx)); |
265 | static int redirect_with_delay_list_safe_p PROTO ((rtx, rtx, rtx)); | |
9c7e2978 RK |
266 | \f |
267 | /* Given X, some rtl, and RES, a pointer to a `struct resource', mark | |
268 | which resources are references by the insn. If INCLUDE_CALLED_ROUTINE | |
269 | is TRUE, resources used by the called routine will be included for | |
270 | CALL_INSNs. */ | |
271 | ||
272 | static void | |
674345b1 | 273 | mark_referenced_resources (x, res, include_delayed_effects) |
9c7e2978 RK |
274 | register rtx x; |
275 | register struct resources *res; | |
674345b1 | 276 | register int include_delayed_effects; |
9c7e2978 RK |
277 | { |
278 | register enum rtx_code code = GET_CODE (x); | |
279 | register int i, j; | |
280 | register char *format_ptr; | |
281 | ||
282 | /* Handle leaf items for which we set resource flags. Also, special-case | |
283 | CALL, SET and CLOBBER operators. */ | |
284 | switch (code) | |
285 | { | |
286 | case CONST: | |
287 | case CONST_INT: | |
288 | case CONST_DOUBLE: | |
289 | case PC: | |
290 | case SYMBOL_REF: | |
291 | case LABEL_REF: | |
292 | return; | |
293 | ||
294 | case SUBREG: | |
295 | if (GET_CODE (SUBREG_REG (x)) != REG) | |
296 | mark_referenced_resources (SUBREG_REG (x), res, 0); | |
297 | else | |
298 | { | |
299 | int regno = REGNO (SUBREG_REG (x)) + SUBREG_WORD (x); | |
300 | int last_regno = regno + HARD_REGNO_NREGS (regno, GET_MODE (x)); | |
301 | for (i = regno; i < last_regno; i++) | |
302 | SET_HARD_REG_BIT (res->regs, i); | |
303 | } | |
304 | return; | |
305 | ||
306 | case REG: | |
307 | for (i = 0; i < HARD_REGNO_NREGS (REGNO (x), GET_MODE (x)); i++) | |
308 | SET_HARD_REG_BIT (res->regs, REGNO (x) + i); | |
309 | return; | |
310 | ||
311 | case MEM: | |
312 | /* If this memory shouldn't change, it really isn't referencing | |
313 | memory. */ | |
8eae5ed6 RK |
314 | if (RTX_UNCHANGING_P (x)) |
315 | res->unch_memory = 1; | |
316 | else | |
9c7e2978 RK |
317 | res->memory = 1; |
318 | res->volatil = MEM_VOLATILE_P (x); | |
319 | ||
320 | /* Mark registers used to access memory. */ | |
321 | mark_referenced_resources (XEXP (x, 0), res, 0); | |
322 | return; | |
323 | ||
324 | case CC0: | |
325 | res->cc = 1; | |
326 | return; | |
327 | ||
6e7348c1 | 328 | case UNSPEC_VOLATILE: |
f1f9081a RS |
329 | case ASM_INPUT: |
330 | /* Traditional asm's are always volatile. */ | |
331 | res->volatil = 1; | |
332 | return; | |
333 | ||
334 | case ASM_OPERANDS: | |
335 | res->volatil = MEM_VOLATILE_P (x); | |
336 | ||
337 | /* For all ASM_OPERANDS, we must traverse the vector of input operands. | |
338 | We can not just fall through here since then we would be confused | |
339 | by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate | |
340 | traditional asms unlike their normal usage. */ | |
341 | ||
342 | for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (x); i++) | |
343 | mark_referenced_resources (ASM_OPERANDS_INPUT (x, i), res, 0); | |
344 | return; | |
345 | ||
9c7e2978 RK |
346 | case CALL: |
347 | /* The first operand will be a (MEM (xxx)) but doesn't really reference | |
348 | memory. The second operand may be referenced, though. */ | |
349 | mark_referenced_resources (XEXP (XEXP (x, 0), 0), res, 0); | |
350 | mark_referenced_resources (XEXP (x, 1), res, 0); | |
351 | return; | |
352 | ||
353 | case SET: | |
354 | /* Usually, the first operand of SET is set, not referenced. But | |
355 | registers used to access memory are referenced. SET_DEST is | |
356 | also referenced if it is a ZERO_EXTRACT or SIGN_EXTRACT. */ | |
357 | ||
358 | mark_referenced_resources (SET_SRC (x), res, 0); | |
359 | ||
360 | x = SET_DEST (x); | |
361 | if (GET_CODE (x) == SIGN_EXTRACT || GET_CODE (x) == ZERO_EXTRACT) | |
362 | mark_referenced_resources (x, res, 0); | |
363 | else if (GET_CODE (x) == SUBREG) | |
364 | x = SUBREG_REG (x); | |
365 | if (GET_CODE (x) == MEM) | |
366 | mark_referenced_resources (XEXP (x, 0), res, 0); | |
367 | return; | |
368 | ||
369 | case CLOBBER: | |
370 | return; | |
371 | ||
372 | case CALL_INSN: | |
674345b1 | 373 | if (include_delayed_effects) |
9c7e2978 RK |
374 | { |
375 | /* A CALL references memory, the frame pointer if it exists, the | |
3462dc45 RK |
376 | stack pointer, any global registers and any registers given in |
377 | USE insns immediately in front of the CALL. | |
9c7e2978 RK |
378 | |
379 | However, we may have moved some of the parameter loading insns | |
380 | into the delay slot of this CALL. If so, the USE's for them | |
381 | don't count and should be skipped. */ | |
382 | rtx insn = PREV_INSN (x); | |
383 | rtx sequence = 0; | |
384 | int seq_size = 0; | |
c9a1bf2e | 385 | rtx next = NEXT_INSN (x); |
9c7e2978 RK |
386 | int i; |
387 | ||
388 | /* If we are part of a delay slot sequence, point at the SEQUENCE. */ | |
389 | if (NEXT_INSN (insn) != x) | |
390 | { | |
c9a1bf2e | 391 | next = NEXT_INSN (NEXT_INSN (insn)); |
9c7e2978 RK |
392 | sequence = PATTERN (NEXT_INSN (insn)); |
393 | seq_size = XVECLEN (sequence, 0); | |
394 | if (GET_CODE (sequence) != SEQUENCE) | |
395 | abort (); | |
396 | } | |
397 | ||
398 | res->memory = 1; | |
399 | SET_HARD_REG_BIT (res->regs, STACK_POINTER_REGNUM); | |
400 | if (frame_pointer_needed) | |
b07ff75d DE |
401 | { |
402 | SET_HARD_REG_BIT (res->regs, FRAME_POINTER_REGNUM); | |
403 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM | |
404 | SET_HARD_REG_BIT (res->regs, HARD_FRAME_POINTER_REGNUM); | |
405 | #endif | |
406 | } | |
9c7e2978 | 407 | |
3462dc45 RK |
408 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
409 | if (global_regs[i]) | |
410 | SET_HARD_REG_BIT (res->regs, i); | |
411 | ||
c9a1bf2e JW |
412 | /* Check for a NOTE_INSN_SETJMP. If it exists, then we must |
413 | assume that this call can need any register. | |
414 | ||
415 | This is done to be more conservative about how we handle setjmp. | |
416 | We assume that they both use and set all registers. Using all | |
417 | registers ensures that a register will not be considered dead | |
418 | just because it crosses a setjmp call. A register should be | |
419 | considered dead only if the setjmp call returns non-zero. */ | |
420 | if (next && GET_CODE (next) == NOTE | |
421 | && NOTE_LINE_NUMBER (next) == NOTE_INSN_SETJMP) | |
422 | SET_HARD_REG_SET (res->regs); | |
423 | ||
44a965f6 DE |
424 | { |
425 | rtx link; | |
426 | ||
427 | for (link = CALL_INSN_FUNCTION_USAGE (x); | |
428 | link; | |
429 | link = XEXP (link, 1)) | |
430 | if (GET_CODE (XEXP (link, 0)) == USE) | |
431 | { | |
432 | for (i = 1; i < seq_size; i++) | |
433 | { | |
434 | rtx slot_pat = PATTERN (XVECEXP (sequence, 0, i)); | |
435 | if (GET_CODE (slot_pat) == SET | |
436 | && rtx_equal_p (SET_DEST (slot_pat), | |
437 | SET_DEST (XEXP (link, 0)))) | |
438 | break; | |
439 | } | |
440 | if (i >= seq_size) | |
441 | mark_referenced_resources (SET_DEST (XEXP (link, 0)), | |
442 | res, 0); | |
443 | } | |
444 | } | |
9c7e2978 RK |
445 | } |
446 | ||
6dc42e49 | 447 | /* ... fall through to other INSN processing ... */ |
9c7e2978 RK |
448 | |
449 | case INSN: | |
450 | case JUMP_INSN: | |
674345b1 JL |
451 | |
452 | #ifdef INSN_REFERENCES_ARE_DELAYED | |
453 | if (! include_delayed_effects | |
454 | && INSN_REFERENCES_ARE_DELAYED (x)) | |
455 | return; | |
456 | #endif | |
457 | ||
9c7e2978 | 458 | /* No special processing, just speed up. */ |
674345b1 | 459 | mark_referenced_resources (PATTERN (x), res, include_delayed_effects); |
9c7e2978 RK |
460 | return; |
461 | } | |
462 | ||
463 | /* Process each sub-expression and flag what it needs. */ | |
464 | format_ptr = GET_RTX_FORMAT (code); | |
465 | for (i = 0; i < GET_RTX_LENGTH (code); i++) | |
466 | switch (*format_ptr++) | |
467 | { | |
468 | case 'e': | |
674345b1 | 469 | mark_referenced_resources (XEXP (x, i), res, include_delayed_effects); |
9c7e2978 RK |
470 | break; |
471 | ||
472 | case 'E': | |
473 | for (j = 0; j < XVECLEN (x, i); j++) | |
474 | mark_referenced_resources (XVECEXP (x, i, j), res, | |
674345b1 | 475 | include_delayed_effects); |
9c7e2978 RK |
476 | break; |
477 | } | |
478 | } | |
479 | \f | |
26d970a5 RK |
480 | /* Given X, a part of an insn, and a pointer to a `struct resource', RES, |
481 | indicate which resources are modified by the insn. If INCLUDE_CALLED_ROUTINE | |
482 | is nonzero, also mark resources potentially set by the called routine. | |
483 | ||
484 | If IN_DEST is nonzero, it means we are inside a SET. Otherwise, | |
485 | objects are being referenced instead of set. | |
9c7e2978 RK |
486 | |
487 | We never mark the insn as modifying the condition code unless it explicitly | |
488 | SETs CC0 even though this is not totally correct. The reason for this is | |
6dc42e49 | 489 | that we require a SET of CC0 to immediately precede the reference to CC0. |
9c7e2978 RK |
490 | So if some other insn sets CC0 as a side-effect, we know it cannot affect |
491 | our computation and thus may be placed in a delay slot. */ | |
492 | ||
493 | static void | |
674345b1 | 494 | mark_set_resources (x, res, in_dest, include_delayed_effects) |
26d970a5 | 495 | register rtx x; |
9c7e2978 | 496 | register struct resources *res; |
26d970a5 | 497 | int in_dest; |
674345b1 | 498 | int include_delayed_effects; |
9c7e2978 | 499 | { |
d2c9e30f | 500 | register enum rtx_code code; |
26d970a5 RK |
501 | register int i, j; |
502 | register char *format_ptr; | |
9c7e2978 | 503 | |
26d970a5 RK |
504 | restart: |
505 | ||
d2c9e30f RK |
506 | code = GET_CODE (x); |
507 | ||
26d970a5 | 508 | switch (code) |
9c7e2978 RK |
509 | { |
510 | case NOTE: | |
511 | case BARRIER: | |
512 | case CODE_LABEL: | |
26d970a5 RK |
513 | case USE: |
514 | case CONST_INT: | |
515 | case CONST_DOUBLE: | |
516 | case LABEL_REF: | |
517 | case SYMBOL_REF: | |
518 | case CONST: | |
519 | case PC: | |
9c7e2978 RK |
520 | /* These don't set any resources. */ |
521 | return; | |
522 | ||
ba12108c RK |
523 | case CC0: |
524 | if (in_dest) | |
525 | res->cc = 1; | |
526 | return; | |
527 | ||
9c7e2978 RK |
528 | case CALL_INSN: |
529 | /* Called routine modifies the condition code, memory, any registers | |
3462dc45 RK |
530 | that aren't saved across calls, global registers and anything |
531 | explicitly CLOBBERed immediately after the CALL_INSN. */ | |
9c7e2978 | 532 | |
674345b1 | 533 | if (include_delayed_effects) |
9c7e2978 | 534 | { |
26d970a5 | 535 | rtx next = NEXT_INSN (x); |
33fe7851 | 536 | rtx prev = PREV_INSN (x); |
5a76b349 | 537 | rtx link; |
9c7e2978 RK |
538 | |
539 | res->cc = res->memory = 1; | |
540 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
3462dc45 | 541 | if (call_used_regs[i] || global_regs[i]) |
9c7e2978 RK |
542 | SET_HARD_REG_BIT (res->regs, i); |
543 | ||
33fe7851 JW |
544 | /* If X is part of a delay slot sequence, then NEXT should be |
545 | the first insn after the sequence. */ | |
546 | if (NEXT_INSN (prev) != x) | |
547 | next = NEXT_INSN (NEXT_INSN (prev)); | |
548 | ||
5a76b349 RK |
549 | for (link = CALL_INSN_FUNCTION_USAGE (x); |
550 | link; link = XEXP (link, 1)) | |
551 | if (GET_CODE (XEXP (link, 0)) == CLOBBER) | |
552 | mark_set_resources (SET_DEST (XEXP (link, 0)), res, 1, 0); | |
33fe7851 JW |
553 | |
554 | /* Check for a NOTE_INSN_SETJMP. If it exists, then we must | |
555 | assume that this call can clobber any register. */ | |
556 | if (next && GET_CODE (next) == NOTE | |
557 | && NOTE_LINE_NUMBER (next) == NOTE_INSN_SETJMP) | |
558 | SET_HARD_REG_SET (res->regs); | |
9c7e2978 RK |
559 | } |
560 | ||
561 | /* ... and also what it's RTL says it modifies, if anything. */ | |
562 | ||
563 | case JUMP_INSN: | |
564 | case INSN: | |
9c7e2978 | 565 | |
26d970a5 RK |
566 | /* An insn consisting of just a CLOBBER (or USE) is just for flow |
567 | and doesn't actually do anything, so we ignore it. */ | |
9c7e2978 | 568 | |
674345b1 JL |
569 | #ifdef INSN_SETS_ARE_DELAYED |
570 | if (! include_delayed_effects | |
571 | && INSN_SETS_ARE_DELAYED (x)) | |
572 | return; | |
573 | #endif | |
574 | ||
26d970a5 RK |
575 | x = PATTERN (x); |
576 | if (GET_CODE (x) != USE && GET_CODE (x) != CLOBBER) | |
577 | goto restart; | |
578 | return; | |
579 | ||
580 | case SET: | |
581 | /* If the source of a SET is a CALL, this is actually done by | |
582 | the called routine. So only include it if we are to include the | |
583 | effects of the calling routine. */ | |
584 | ||
585 | mark_set_resources (SET_DEST (x), res, | |
674345b1 | 586 | (include_delayed_effects |
26d970a5 RK |
587 | || GET_CODE (SET_SRC (x)) != CALL), |
588 | 0); | |
589 | ||
590 | mark_set_resources (SET_SRC (x), res, 0, 0); | |
591 | return; | |
592 | ||
593 | case CLOBBER: | |
594 | mark_set_resources (XEXP (x, 0), res, 1, 0); | |
595 | return; | |
596 | ||
597 | case SEQUENCE: | |
598 | for (i = 0; i < XVECLEN (x, 0); i++) | |
599 | if (! (INSN_ANNULLED_BRANCH_P (XVECEXP (x, 0, 0)) | |
600 | && INSN_FROM_TARGET_P (XVECEXP (x, 0, i)))) | |
601 | mark_set_resources (XVECEXP (x, 0, i), res, 0, | |
674345b1 | 602 | include_delayed_effects); |
26d970a5 RK |
603 | return; |
604 | ||
605 | case POST_INC: | |
606 | case PRE_INC: | |
607 | case POST_DEC: | |
608 | case PRE_DEC: | |
609 | mark_set_resources (XEXP (x, 0), res, 1, 0); | |
610 | return; | |
611 | ||
612 | case ZERO_EXTRACT: | |
613 | mark_set_resources (XEXP (x, 0), res, in_dest, 0); | |
614 | mark_set_resources (XEXP (x, 1), res, 0, 0); | |
615 | mark_set_resources (XEXP (x, 2), res, 0, 0); | |
616 | return; | |
617 | ||
618 | case MEM: | |
619 | if (in_dest) | |
620 | { | |
621 | res->memory = 1; | |
8eae5ed6 | 622 | res->unch_memory = RTX_UNCHANGING_P (x); |
26d970a5 RK |
623 | res->volatil = MEM_VOLATILE_P (x); |
624 | } | |
625 | ||
626 | mark_set_resources (XEXP (x, 0), res, 0, 0); | |
d2c9e30f | 627 | return; |
26d970a5 | 628 | |
f4f56bb7 RK |
629 | case SUBREG: |
630 | if (in_dest) | |
631 | { | |
632 | if (GET_CODE (SUBREG_REG (x)) != REG) | |
633 | mark_set_resources (SUBREG_REG (x), res, | |
634 | in_dest, include_delayed_effects); | |
635 | else | |
636 | { | |
637 | int regno = REGNO (SUBREG_REG (x)) + SUBREG_WORD (x); | |
638 | int last_regno = regno + HARD_REGNO_NREGS (regno, GET_MODE (x)); | |
639 | for (i = regno; i < last_regno; i++) | |
640 | SET_HARD_REG_BIT (res->regs, i); | |
641 | } | |
642 | } | |
643 | return; | |
644 | ||
26d970a5 | 645 | case REG: |
4323a0e1 JL |
646 | if (in_dest) |
647 | for (i = 0; i < HARD_REGNO_NREGS (REGNO (x), GET_MODE (x)); i++) | |
648 | SET_HARD_REG_BIT (res->regs, REGNO (x) + i); | |
26d970a5 | 649 | return; |
9c7e2978 | 650 | } |
26d970a5 RK |
651 | |
652 | /* Process each sub-expression and flag what it needs. */ | |
653 | format_ptr = GET_RTX_FORMAT (code); | |
654 | for (i = 0; i < GET_RTX_LENGTH (code); i++) | |
655 | switch (*format_ptr++) | |
656 | { | |
657 | case 'e': | |
674345b1 | 658 | mark_set_resources (XEXP (x, i), res, in_dest, include_delayed_effects); |
26d970a5 RK |
659 | break; |
660 | ||
661 | case 'E': | |
662 | for (j = 0; j < XVECLEN (x, i); j++) | |
663 | mark_set_resources (XVECEXP (x, i, j), res, in_dest, | |
674345b1 | 664 | include_delayed_effects); |
26d970a5 RK |
665 | break; |
666 | } | |
9c7e2978 RK |
667 | } |
668 | \f | |
669 | /* Return TRUE if this insn should stop the search for insn to fill delay | |
670 | slots. LABELS_P indicates that labels should terminate the search. | |
671 | In all cases, jumps terminate the search. */ | |
672 | ||
673 | static int | |
674 | stop_search_p (insn, labels_p) | |
675 | rtx insn; | |
676 | int labels_p; | |
677 | { | |
678 | if (insn == 0) | |
679 | return 1; | |
680 | ||
681 | switch (GET_CODE (insn)) | |
682 | { | |
683 | case NOTE: | |
684 | case CALL_INSN: | |
685 | return 0; | |
686 | ||
687 | case CODE_LABEL: | |
688 | return labels_p; | |
689 | ||
690 | case JUMP_INSN: | |
691 | case BARRIER: | |
692 | return 1; | |
693 | ||
694 | case INSN: | |
695 | /* OK unless it contains a delay slot or is an `asm' insn of some type. | |
696 | We don't know anything about these. */ | |
697 | return (GET_CODE (PATTERN (insn)) == SEQUENCE | |
698 | || GET_CODE (PATTERN (insn)) == ASM_INPUT | |
699 | || asm_noperands (PATTERN (insn)) >= 0); | |
700 | ||
701 | default: | |
702 | abort (); | |
703 | } | |
704 | } | |
705 | \f | |
706 | /* Return TRUE if any resources are marked in both RES1 and RES2 or if either | |
707 | resource set contains a volatile memory reference. Otherwise, return FALSE. */ | |
708 | ||
709 | static int | |
710 | resource_conflicts_p (res1, res2) | |
711 | struct resources *res1, *res2; | |
712 | { | |
713 | if ((res1->cc && res2->cc) || (res1->memory && res2->memory) | |
8eae5ed6 | 714 | || (res1->unch_memory && res2->unch_memory) |
9c7e2978 RK |
715 | || res1->volatil || res2->volatil) |
716 | return 1; | |
717 | ||
718 | #ifdef HARD_REG_SET | |
719 | return (res1->regs & res2->regs) != HARD_CONST (0); | |
720 | #else | |
721 | { | |
722 | int i; | |
723 | ||
724 | for (i = 0; i < HARD_REG_SET_LONGS; i++) | |
725 | if ((res1->regs[i] & res2->regs[i]) != 0) | |
726 | return 1; | |
727 | return 0; | |
728 | } | |
729 | #endif | |
730 | } | |
731 | ||
732 | /* Return TRUE if any resource marked in RES, a `struct resources', is | |
733 | referenced by INSN. If INCLUDE_CALLED_ROUTINE is set, return if the called | |
734 | routine is using those resources. | |
735 | ||
736 | We compute this by computing all the resources referenced by INSN and | |
737 | seeing if this conflicts with RES. It might be faster to directly check | |
738 | ourselves, and this is the way it used to work, but it means duplicating | |
739 | a large block of complex code. */ | |
740 | ||
741 | static int | |
674345b1 | 742 | insn_references_resource_p (insn, res, include_delayed_effects) |
9c7e2978 RK |
743 | register rtx insn; |
744 | register struct resources *res; | |
674345b1 | 745 | int include_delayed_effects; |
9c7e2978 RK |
746 | { |
747 | struct resources insn_res; | |
748 | ||
749 | CLEAR_RESOURCE (&insn_res); | |
674345b1 | 750 | mark_referenced_resources (insn, &insn_res, include_delayed_effects); |
9c7e2978 RK |
751 | return resource_conflicts_p (&insn_res, res); |
752 | } | |
753 | ||
754 | /* Return TRUE if INSN modifies resources that are marked in RES. | |
755 | INCLUDE_CALLED_ROUTINE is set if the actions of that routine should be | |
756 | included. CC0 is only modified if it is explicitly set; see comments | |
757 | in front of mark_set_resources for details. */ | |
758 | ||
759 | static int | |
674345b1 | 760 | insn_sets_resource_p (insn, res, include_delayed_effects) |
9c7e2978 RK |
761 | register rtx insn; |
762 | register struct resources *res; | |
674345b1 | 763 | int include_delayed_effects; |
9c7e2978 RK |
764 | { |
765 | struct resources insn_sets; | |
766 | ||
767 | CLEAR_RESOURCE (&insn_sets); | |
674345b1 | 768 | mark_set_resources (insn, &insn_sets, 0, include_delayed_effects); |
9c7e2978 RK |
769 | return resource_conflicts_p (&insn_sets, res); |
770 | } | |
771 | \f | |
772 | /* Find a label at the end of the function or before a RETURN. If there is | |
773 | none, make one. */ | |
774 | ||
775 | static rtx | |
776 | find_end_label () | |
777 | { | |
778 | rtx insn; | |
779 | ||
780 | /* If we found one previously, return it. */ | |
781 | if (end_of_function_label) | |
782 | return end_of_function_label; | |
783 | ||
784 | /* Otherwise, see if there is a label at the end of the function. If there | |
785 | is, it must be that RETURN insns aren't needed, so that is our return | |
786 | label and we don't have to do anything else. */ | |
787 | ||
788 | insn = get_last_insn (); | |
789 | while (GET_CODE (insn) == NOTE | |
790 | || (GET_CODE (insn) == INSN | |
791 | && (GET_CODE (PATTERN (insn)) == USE | |
792 | || GET_CODE (PATTERN (insn)) == CLOBBER))) | |
793 | insn = PREV_INSN (insn); | |
794 | ||
e572bad3 JL |
795 | /* When a target threads its epilogue we might already have a |
796 | suitable return insn. If so put a label before it for the | |
797 | end_of_function_label. */ | |
798 | if (GET_CODE (insn) == BARRIER | |
799 | && GET_CODE (PREV_INSN (insn)) == JUMP_INSN | |
800 | && GET_CODE (PATTERN (PREV_INSN (insn))) == RETURN) | |
801 | { | |
802 | rtx temp = PREV_INSN (PREV_INSN (insn)); | |
803 | end_of_function_label = gen_label_rtx (); | |
804 | LABEL_NUSES (end_of_function_label) = 0; | |
805 | ||
806 | /* Put the label before an USE insns that may proceed the RETURN insn. */ | |
807 | while (GET_CODE (temp) == USE) | |
808 | temp = PREV_INSN (temp); | |
809 | ||
810 | emit_label_after (end_of_function_label, temp); | |
811 | } | |
812 | ||
813 | else if (GET_CODE (insn) == CODE_LABEL) | |
814 | end_of_function_label = insn; | |
9c7e2978 RK |
815 | else |
816 | { | |
817 | /* Otherwise, make a new label and emit a RETURN and BARRIER, | |
818 | if needed. */ | |
819 | end_of_function_label = gen_label_rtx (); | |
820 | LABEL_NUSES (end_of_function_label) = 0; | |
821 | emit_label (end_of_function_label); | |
822 | #ifdef HAVE_return | |
823 | if (HAVE_return) | |
824 | { | |
5fcd63d0 | 825 | /* The return we make may have delay slots too. */ |
2dff5a06 RS |
826 | rtx insn = gen_return (); |
827 | insn = emit_jump_insn (insn); | |
9c7e2978 | 828 | emit_barrier (); |
5fcd63d0 JL |
829 | if (num_delay_slots (insn) > 0) |
830 | obstack_ptr_grow (&unfilled_slots_obstack, insn); | |
9c7e2978 RK |
831 | } |
832 | #endif | |
833 | } | |
834 | ||
835 | /* Show one additional use for this label so it won't go away until | |
836 | we are done. */ | |
837 | ++LABEL_NUSES (end_of_function_label); | |
838 | ||
839 | return end_of_function_label; | |
840 | } | |
841 | \f | |
842 | /* Put INSN and LIST together in a SEQUENCE rtx of LENGTH, and replace | |
843 | the pattern of INSN with the SEQUENCE. | |
844 | ||
845 | Chain the insns so that NEXT_INSN of each insn in the sequence points to | |
846 | the next and NEXT_INSN of the last insn in the sequence points to | |
847 | the first insn after the sequence. Similarly for PREV_INSN. This makes | |
848 | it easier to scan all insns. | |
849 | ||
850 | Returns the SEQUENCE that replaces INSN. */ | |
851 | ||
852 | static rtx | |
853 | emit_delay_sequence (insn, list, length, avail) | |
854 | rtx insn; | |
855 | rtx list; | |
856 | int length; | |
857 | int avail; | |
858 | { | |
859 | register int i = 1; | |
860 | register rtx li; | |
861 | int had_barrier = 0; | |
862 | ||
863 | /* Allocate the the rtvec to hold the insns and the SEQUENCE. */ | |
864 | rtvec seqv = rtvec_alloc (length + 1); | |
865 | rtx seq = gen_rtx (SEQUENCE, VOIDmode, seqv); | |
866 | rtx seq_insn = make_insn_raw (seq); | |
867 | rtx first = get_insns (); | |
868 | rtx last = get_last_insn (); | |
869 | ||
870 | /* Make a copy of the insn having delay slots. */ | |
871 | rtx delay_insn = copy_rtx (insn); | |
872 | ||
873 | /* If INSN is followed by a BARRIER, delete the BARRIER since it will only | |
874 | confuse further processing. Update LAST in case it was the last insn. | |
875 | We will put the BARRIER back in later. */ | |
876 | if (NEXT_INSN (insn) && GET_CODE (NEXT_INSN (insn)) == BARRIER) | |
877 | { | |
878 | delete_insn (NEXT_INSN (insn)); | |
879 | last = get_last_insn (); | |
880 | had_barrier = 1; | |
881 | } | |
882 | ||
883 | /* Splice our SEQUENCE into the insn stream where INSN used to be. */ | |
884 | NEXT_INSN (seq_insn) = NEXT_INSN (insn); | |
885 | PREV_INSN (seq_insn) = PREV_INSN (insn); | |
886 | ||
887 | if (insn == last) | |
888 | set_new_first_and_last_insn (first, seq_insn); | |
889 | else | |
890 | PREV_INSN (NEXT_INSN (seq_insn)) = seq_insn; | |
891 | ||
892 | if (insn == first) | |
893 | set_new_first_and_last_insn (seq_insn, last); | |
894 | else | |
895 | NEXT_INSN (PREV_INSN (seq_insn)) = seq_insn; | |
896 | ||
897 | /* Build our SEQUENCE and rebuild the insn chain. */ | |
898 | XVECEXP (seq, 0, 0) = delay_insn; | |
899 | INSN_DELETED_P (delay_insn) = 0; | |
900 | PREV_INSN (delay_insn) = PREV_INSN (seq_insn); | |
901 | ||
902 | for (li = list; li; li = XEXP (li, 1), i++) | |
903 | { | |
904 | rtx tem = XEXP (li, 0); | |
905 | rtx note; | |
906 | ||
907 | /* Show that this copy of the insn isn't deleted. */ | |
908 | INSN_DELETED_P (tem) = 0; | |
909 | ||
910 | XVECEXP (seq, 0, i) = tem; | |
911 | PREV_INSN (tem) = XVECEXP (seq, 0, i - 1); | |
912 | NEXT_INSN (XVECEXP (seq, 0, i - 1)) = tem; | |
913 | ||
914 | /* Remove any REG_DEAD notes because we can't rely on them now | |
915 | that the insn has been moved. */ | |
916 | for (note = REG_NOTES (tem); note; note = XEXP (note, 1)) | |
917 | if (REG_NOTE_KIND (note) == REG_DEAD) | |
918 | XEXP (note, 0) = const0_rtx; | |
919 | } | |
920 | ||
921 | NEXT_INSN (XVECEXP (seq, 0, length)) = NEXT_INSN (seq_insn); | |
922 | ||
f1f9081a RS |
923 | /* If the previous insn is a SEQUENCE, update the NEXT_INSN pointer on the |
924 | last insn in that SEQUENCE to point to us. Similarly for the first | |
925 | insn in the following insn if it is a SEQUENCE. */ | |
926 | ||
927 | if (PREV_INSN (seq_insn) && GET_CODE (PREV_INSN (seq_insn)) == INSN | |
928 | && GET_CODE (PATTERN (PREV_INSN (seq_insn))) == SEQUENCE) | |
929 | NEXT_INSN (XVECEXP (PATTERN (PREV_INSN (seq_insn)), 0, | |
930 | XVECLEN (PATTERN (PREV_INSN (seq_insn)), 0) - 1)) | |
931 | = seq_insn; | |
932 | ||
933 | if (NEXT_INSN (seq_insn) && GET_CODE (NEXT_INSN (seq_insn)) == INSN | |
934 | && GET_CODE (PATTERN (NEXT_INSN (seq_insn))) == SEQUENCE) | |
935 | PREV_INSN (XVECEXP (PATTERN (NEXT_INSN (seq_insn)), 0, 0)) = seq_insn; | |
936 | ||
9c7e2978 RK |
937 | /* If there used to be a BARRIER, put it back. */ |
938 | if (had_barrier) | |
939 | emit_barrier_after (seq_insn); | |
940 | ||
941 | if (i != length + 1) | |
942 | abort (); | |
943 | ||
944 | return seq_insn; | |
945 | } | |
946 | ||
947 | /* Add INSN to DELAY_LIST and return the head of the new list. The list must | |
948 | be in the order in which the insns are to be executed. */ | |
949 | ||
950 | static rtx | |
951 | add_to_delay_list (insn, delay_list) | |
952 | rtx insn; | |
953 | rtx delay_list; | |
954 | { | |
c8cfe1f6 RK |
955 | /* If we have an empty list, just make a new list element. If |
956 | INSN has it's block number recorded, clear it since we may | |
957 | be moving the insn to a new block. */ | |
958 | ||
9c7e2978 | 959 | if (delay_list == 0) |
c8cfe1f6 RK |
960 | { |
961 | struct target_info *tinfo; | |
962 | ||
963 | for (tinfo = target_hash_table[INSN_UID (insn) % TARGET_HASH_PRIME]; | |
964 | tinfo; tinfo = tinfo->next) | |
965 | if (tinfo->uid == INSN_UID (insn)) | |
966 | break; | |
967 | ||
968 | if (tinfo) | |
969 | tinfo->block = -1; | |
970 | ||
971 | return gen_rtx (INSN_LIST, VOIDmode, insn, NULL_RTX); | |
972 | } | |
9c7e2978 RK |
973 | |
974 | /* Otherwise this must be an INSN_LIST. Add INSN to the end of the | |
975 | list. */ | |
976 | XEXP (delay_list, 1) = add_to_delay_list (insn, XEXP (delay_list, 1)); | |
977 | ||
978 | return delay_list; | |
979 | } | |
9c7e2978 RK |
980 | \f |
981 | /* Delete INSN from the the delay slot of the insn that it is in. This may | |
982 | produce an insn without anything in its delay slots. */ | |
983 | ||
984 | static void | |
985 | delete_from_delay_slot (insn) | |
986 | rtx insn; | |
987 | { | |
988 | rtx trial, seq_insn, seq, prev; | |
989 | rtx delay_list = 0; | |
990 | int i; | |
991 | ||
992 | /* We first must find the insn containing the SEQUENCE with INSN in its | |
993 | delay slot. Do this by finding an insn, TRIAL, where | |
994 | PREV_INSN (NEXT_INSN (TRIAL)) != TRIAL. */ | |
995 | ||
996 | for (trial = insn; | |
997 | PREV_INSN (NEXT_INSN (trial)) == trial; | |
998 | trial = NEXT_INSN (trial)) | |
999 | ; | |
1000 | ||
1001 | seq_insn = PREV_INSN (NEXT_INSN (trial)); | |
1002 | seq = PATTERN (seq_insn); | |
1003 | ||
1004 | /* Create a delay list consisting of all the insns other than the one | |
1005 | we are deleting (unless we were the only one). */ | |
1006 | if (XVECLEN (seq, 0) > 2) | |
1007 | for (i = 1; i < XVECLEN (seq, 0); i++) | |
1008 | if (XVECEXP (seq, 0, i) != insn) | |
1009 | delay_list = add_to_delay_list (XVECEXP (seq, 0, i), delay_list); | |
1010 | ||
1011 | /* Delete the old SEQUENCE, re-emit the insn that used to have the delay | |
1012 | list, and rebuild the delay list if non-empty. */ | |
1013 | prev = PREV_INSN (seq_insn); | |
1014 | trial = XVECEXP (seq, 0, 0); | |
1015 | delete_insn (seq_insn); | |
1016 | add_insn_after (trial, prev); | |
1017 | ||
1018 | if (GET_CODE (trial) == JUMP_INSN | |
1019 | && (simplejump_p (trial) || GET_CODE (PATTERN (trial)) == RETURN)) | |
1020 | emit_barrier_after (trial); | |
1021 | ||
1022 | /* If there are any delay insns, remit them. Otherwise clear the | |
1023 | annul flag. */ | |
1024 | if (delay_list) | |
f1f9081a | 1025 | trial = emit_delay_sequence (trial, delay_list, XVECLEN (seq, 0) - 2, 0); |
9c7e2978 RK |
1026 | else |
1027 | INSN_ANNULLED_BRANCH_P (trial) = 0; | |
1028 | ||
1029 | INSN_FROM_TARGET_P (insn) = 0; | |
1030 | ||
1031 | /* Show we need to fill this insn again. */ | |
1032 | obstack_ptr_grow (&unfilled_slots_obstack, trial); | |
1033 | } | |
1034 | \f | |
1035 | /* Delete INSN, a JUMP_INSN. If it is a conditional jump, we must track down | |
1036 | the insn that sets CC0 for it and delete it too. */ | |
1037 | ||
1038 | static void | |
1039 | delete_scheduled_jump (insn) | |
1040 | rtx insn; | |
1041 | { | |
1042 | /* Delete the insn that sets cc0 for us. On machines without cc0, we could | |
1043 | delete the insn that sets the condition code, but it is hard to find it. | |
1044 | Since this case is rare anyway, don't bother trying; there would likely | |
1045 | be other insns that became dead anyway, which we wouldn't know to | |
1046 | delete. */ | |
1047 | ||
1048 | #ifdef HAVE_cc0 | |
1049 | if (reg_mentioned_p (cc0_rtx, insn)) | |
1050 | { | |
fb3821f7 | 1051 | rtx note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX); |
9c7e2978 RK |
1052 | |
1053 | /* If a reg-note was found, it points to an insn to set CC0. This | |
1054 | insn is in the delay list of some other insn. So delete it from | |
1055 | the delay list it was in. */ | |
1056 | if (note) | |
1057 | { | |
fb3821f7 | 1058 | if (! FIND_REG_INC_NOTE (XEXP (note, 0), NULL_RTX) |
9c7e2978 RK |
1059 | && sets_cc0_p (PATTERN (XEXP (note, 0))) == 1) |
1060 | delete_from_delay_slot (XEXP (note, 0)); | |
1061 | } | |
1062 | else | |
1063 | { | |
1064 | /* The insn setting CC0 is our previous insn, but it may be in | |
1065 | a delay slot. It will be the last insn in the delay slot, if | |
1066 | it is. */ | |
1067 | rtx trial = previous_insn (insn); | |
1068 | if (GET_CODE (trial) == NOTE) | |
1069 | trial = prev_nonnote_insn (trial); | |
1070 | if (sets_cc0_p (PATTERN (trial)) != 1 | |
1071 | || FIND_REG_INC_NOTE (trial, 0)) | |
1072 | return; | |
1073 | if (PREV_INSN (NEXT_INSN (trial)) == trial) | |
1074 | delete_insn (trial); | |
1075 | else | |
1076 | delete_from_delay_slot (trial); | |
1077 | } | |
1078 | } | |
1079 | #endif | |
1080 | ||
1081 | delete_insn (insn); | |
1082 | } | |
1083 | \f | |
1084 | /* Counters for delay-slot filling. */ | |
1085 | ||
1086 | #define NUM_REORG_FUNCTIONS 2 | |
1087 | #define MAX_DELAY_HISTOGRAM 3 | |
1088 | #define MAX_REORG_PASSES 2 | |
1089 | ||
1090 | static int num_insns_needing_delays[NUM_REORG_FUNCTIONS][MAX_REORG_PASSES]; | |
1091 | ||
1092 | static int num_filled_delays[NUM_REORG_FUNCTIONS][MAX_DELAY_HISTOGRAM+1][MAX_REORG_PASSES]; | |
1093 | ||
1094 | static int reorg_pass_number; | |
1095 | ||
1096 | static void | |
1097 | note_delay_statistics (slots_filled, index) | |
1098 | int slots_filled, index; | |
1099 | { | |
1100 | num_insns_needing_delays[index][reorg_pass_number]++; | |
1101 | if (slots_filled > MAX_DELAY_HISTOGRAM) | |
1102 | slots_filled = MAX_DELAY_HISTOGRAM; | |
1103 | num_filled_delays[index][slots_filled][reorg_pass_number]++; | |
1104 | } | |
1105 | \f | |
1106 | #if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS) | |
1107 | ||
1108 | /* Optimize the following cases: | |
1109 | ||
1110 | 1. When a conditional branch skips over only one instruction, | |
1111 | use an annulling branch and put that insn in the delay slot. | |
6dc42e49 RS |
1112 | Use either a branch that annuls when the condition if true or |
1113 | invert the test with a branch that annuls when the condition is | |
9c7e2978 RK |
1114 | false. This saves insns, since otherwise we must copy an insn |
1115 | from the L1 target. | |
1116 | ||
1117 | (orig) (skip) (otherwise) | |
1118 | Bcc.n L1 Bcc',a L1 Bcc,a L1' | |
1119 | insn insn insn2 | |
1120 | L1: L1: L1: | |
1121 | insn2 insn2 insn2 | |
1122 | insn3 insn3 L1': | |
1123 | insn3 | |
1124 | ||
1125 | 2. When a conditional branch skips over only one instruction, | |
1126 | and after that, it unconditionally branches somewhere else, | |
1127 | perform the similar optimization. This saves executing the | |
1128 | second branch in the case where the inverted condition is true. | |
1129 | ||
1130 | Bcc.n L1 Bcc',a L2 | |
1131 | insn insn | |
1132 | L1: L1: | |
1133 | Bra L2 Bra L2 | |
1134 | ||
1135 | INSN is a JUMP_INSN. | |
1136 | ||
1137 | This should be expanded to skip over N insns, where N is the number | |
1138 | of delay slots required. */ | |
1139 | ||
1140 | static rtx | |
1141 | optimize_skip (insn) | |
1142 | register rtx insn; | |
1143 | { | |
1144 | register rtx trial = next_nonnote_insn (insn); | |
1145 | rtx next_trial = next_active_insn (trial); | |
1146 | rtx delay_list = 0; | |
1147 | rtx target_label; | |
35523fce JL |
1148 | int flags; |
1149 | ||
1150 | flags = get_jump_flags (insn, JUMP_LABEL (insn)); | |
9c7e2978 RK |
1151 | |
1152 | if (trial == 0 | |
1153 | || GET_CODE (trial) != INSN | |
1154 | || GET_CODE (PATTERN (trial)) == SEQUENCE | |
1155 | || recog_memoized (trial) < 0 | |
35523fce JL |
1156 | || (! eligible_for_annul_false (insn, 0, trial, flags) |
1157 | && ! eligible_for_annul_true (insn, 0, trial, flags))) | |
9c7e2978 RK |
1158 | return 0; |
1159 | ||
1160 | /* There are two cases where we are just executing one insn (we assume | |
1161 | here that a branch requires only one insn; this should be generalized | |
1162 | at some point): Where the branch goes around a single insn or where | |
1163 | we have one insn followed by a branch to the same label we branch to. | |
1164 | In both of these cases, inverting the jump and annulling the delay | |
1165 | slot give the same effect in fewer insns. */ | |
1166 | if ((next_trial == next_active_insn (JUMP_LABEL (insn))) | |
1167 | || (next_trial != 0 | |
1168 | && GET_CODE (next_trial) == JUMP_INSN | |
1169 | && JUMP_LABEL (insn) == JUMP_LABEL (next_trial) | |
1170 | && (simplejump_p (next_trial) | |
1171 | || GET_CODE (PATTERN (next_trial)) == RETURN))) | |
1172 | { | |
35523fce | 1173 | if (eligible_for_annul_false (insn, 0, trial, flags)) |
9c7e2978 RK |
1174 | { |
1175 | if (invert_jump (insn, JUMP_LABEL (insn))) | |
1176 | INSN_FROM_TARGET_P (trial) = 1; | |
35523fce | 1177 | else if (! eligible_for_annul_true (insn, 0, trial, flags)) |
9c7e2978 RK |
1178 | return 0; |
1179 | } | |
1180 | ||
fb3821f7 | 1181 | delay_list = add_to_delay_list (trial, NULL_RTX); |
9c7e2978 RK |
1182 | next_trial = next_active_insn (trial); |
1183 | update_block (trial, trial); | |
1184 | delete_insn (trial); | |
1185 | ||
1186 | /* Also, if we are targeting an unconditional | |
1187 | branch, thread our jump to the target of that branch. Don't | |
1188 | change this into a RETURN here, because it may not accept what | |
1189 | we have in the delay slot. We'll fix this up later. */ | |
1190 | if (next_trial && GET_CODE (next_trial) == JUMP_INSN | |
1191 | && (simplejump_p (next_trial) | |
1192 | || GET_CODE (PATTERN (next_trial)) == RETURN)) | |
1193 | { | |
1194 | target_label = JUMP_LABEL (next_trial); | |
1195 | if (target_label == 0) | |
1196 | target_label = find_end_label (); | |
0e5bad53 JL |
1197 | |
1198 | /* Recompute the flags based on TARGET_LABEL since threading | |
1199 | the jump to TARGET_LABEL may change the direction of the | |
1200 | jump (which may change the circumstances in which the | |
1201 | delay slot is nullified). */ | |
1202 | flags = get_jump_flags (insn, target_label); | |
1203 | if (eligible_for_annul_true (insn, 0, trial, flags)) | |
1204 | reorg_redirect_jump (insn, target_label); | |
9c7e2978 RK |
1205 | } |
1206 | ||
1207 | INSN_ANNULLED_BRANCH_P (insn) = 1; | |
1208 | } | |
1209 | ||
1210 | return delay_list; | |
1211 | } | |
1212 | #endif | |
1213 | \f | |
35523fce JL |
1214 | |
1215 | /* Encode and return branch direction and prediction information for | |
1216 | INSN assuming it will jump to LABEL. | |
1217 | ||
1218 | Non conditional branches return no direction information and | |
1219 | are predicted as very likely taken. */ | |
1220 | static int | |
1221 | get_jump_flags (insn, label) | |
1222 | rtx insn, label; | |
1223 | { | |
1224 | int flags; | |
1225 | ||
1226 | /* get_jump_flags can be passed any insn with delay slots, these may | |
1227 | be INSNs, CALL_INSNs, or JUMP_INSNs. Only JUMP_INSNs have branch | |
1228 | direction information, and only if they are conditional jumps. | |
1229 | ||
1230 | If LABEL is zero, then there is no way to determine the branch | |
1231 | direction. */ | |
1232 | if (GET_CODE (insn) == JUMP_INSN | |
3480bb98 | 1233 | && (condjump_p (insn) || condjump_in_parallel_p (insn)) |
35523fce | 1234 | && INSN_UID (insn) <= max_uid |
e328af29 RK |
1235 | && label != 0 |
1236 | && INSN_UID (label) <= max_uid) | |
35523fce JL |
1237 | flags |
1238 | = (uid_to_ruid[INSN_UID (label)] > uid_to_ruid[INSN_UID (insn)]) | |
1239 | ? ATTR_FLAG_forward : ATTR_FLAG_backward; | |
1240 | /* No valid direction information. */ | |
1241 | else | |
1242 | flags = 0; | |
1243 | ||
1244 | /* If insn is a conditional branch call mostly_true_jump to get | |
1245 | determine the branch prediction. | |
1246 | ||
1247 | Non conditional branches are predicted as very likely taken. */ | |
1248 | if (GET_CODE (insn) == JUMP_INSN | |
3480bb98 | 1249 | && (condjump_p (insn) || condjump_in_parallel_p (insn))) |
35523fce JL |
1250 | { |
1251 | int prediction; | |
1252 | ||
1253 | prediction = mostly_true_jump (insn, get_branch_condition (insn, label)); | |
1254 | switch (prediction) | |
1255 | { | |
1256 | case 2: | |
1257 | flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely); | |
1258 | break; | |
1259 | case 1: | |
1260 | flags |= ATTR_FLAG_likely; | |
1261 | break; | |
35523fce JL |
1262 | case 0: |
1263 | flags |= ATTR_FLAG_unlikely; | |
1264 | break; | |
35523fce JL |
1265 | case -1: |
1266 | flags |= (ATTR_FLAG_very_unlikely | ATTR_FLAG_unlikely); | |
1267 | break; | |
1268 | ||
1269 | default: | |
1270 | abort(); | |
1271 | } | |
1272 | } | |
1273 | else | |
1274 | flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely); | |
1275 | ||
1276 | return flags; | |
1277 | } | |
1278 | ||
65753f55 | 1279 | /* Return 1 if INSN is a destination that will be branched to rarely (the |
0275a51b RK |
1280 | return point of a function); return 2 if DEST will be branched to very |
1281 | rarely (a call to a function that doesn't return). Otherwise, | |
1282 | return 0. */ | |
1283 | ||
1284 | static int | |
1285 | rare_destination (insn) | |
1286 | rtx insn; | |
1287 | { | |
1288 | int jump_count = 0; | |
65753f55 | 1289 | rtx next; |
0275a51b | 1290 | |
65753f55 | 1291 | for (; insn; insn = next) |
0275a51b RK |
1292 | { |
1293 | if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == SEQUENCE) | |
1294 | insn = XVECEXP (PATTERN (insn), 0, 0); | |
1295 | ||
65753f55 RK |
1296 | next = NEXT_INSN (insn); |
1297 | ||
0275a51b RK |
1298 | switch (GET_CODE (insn)) |
1299 | { | |
1300 | case CODE_LABEL: | |
1301 | return 0; | |
1302 | case BARRIER: | |
1303 | /* A BARRIER can either be after a JUMP_INSN or a CALL_INSN. We | |
1304 | don't scan past JUMP_INSNs, so any barrier we find here must | |
1305 | have been after a CALL_INSN and hence mean the call doesn't | |
1306 | return. */ | |
1307 | return 2; | |
1308 | case JUMP_INSN: | |
1309 | if (GET_CODE (PATTERN (insn)) == RETURN) | |
1310 | return 1; | |
1311 | else if (simplejump_p (insn) | |
1312 | && jump_count++ < 10) | |
65753f55 | 1313 | next = JUMP_LABEL (insn); |
0275a51b RK |
1314 | else |
1315 | return 0; | |
1316 | } | |
1317 | } | |
1318 | ||
1319 | /* If we got here it means we hit the end of the function. So this | |
1320 | is an unlikely destination. */ | |
1321 | ||
1322 | return 1; | |
1323 | } | |
1324 | ||
9c7e2978 RK |
1325 | /* Return truth value of the statement that this branch |
1326 | is mostly taken. If we think that the branch is extremely likely | |
1327 | to be taken, we return 2. If the branch is slightly more likely to be | |
0275a51b RK |
1328 | taken, return 1. If the branch is slightly less likely to be taken, |
1329 | return 0 and if the branch is highly unlikely to be taken, return -1. | |
9c7e2978 RK |
1330 | |
1331 | CONDITION, if non-zero, is the condition that JUMP_INSN is testing. */ | |
1332 | ||
1333 | static int | |
1334 | mostly_true_jump (jump_insn, condition) | |
1335 | rtx jump_insn, condition; | |
1336 | { | |
1337 | rtx target_label = JUMP_LABEL (jump_insn); | |
1338 | rtx insn; | |
0275a51b RK |
1339 | int rare_dest = rare_destination (target_label); |
1340 | int rare_fallthrough = rare_destination (NEXT_INSN (jump_insn)); | |
1341 | ||
1342 | /* If this is a branch outside a loop, it is highly unlikely. */ | |
1343 | if (GET_CODE (PATTERN (jump_insn)) == SET | |
1344 | && GET_CODE (SET_SRC (PATTERN (jump_insn))) == IF_THEN_ELSE | |
1345 | && ((GET_CODE (XEXP (SET_SRC (PATTERN (jump_insn)), 1)) == LABEL_REF | |
1346 | && LABEL_OUTSIDE_LOOP_P (XEXP (SET_SRC (PATTERN (jump_insn)), 1))) | |
1347 | || (GET_CODE (XEXP (SET_SRC (PATTERN (jump_insn)), 2)) == LABEL_REF | |
1348 | && LABEL_OUTSIDE_LOOP_P (XEXP (SET_SRC (PATTERN (jump_insn)), 2))))) | |
1349 | return -1; | |
1350 | ||
1351 | if (target_label) | |
4d0e69c3 | 1352 | { |
0275a51b RK |
1353 | /* If this is the test of a loop, it is very likely true. We scan |
1354 | backwards from the target label. If we find a NOTE_INSN_LOOP_BEG | |
1355 | before the next real insn, we assume the branch is to the top of | |
1356 | the loop. */ | |
1357 | for (insn = PREV_INSN (target_label); | |
1358 | insn && GET_CODE (insn) == NOTE; | |
1359 | insn = PREV_INSN (insn)) | |
1360 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) | |
1361 | return 2; | |
1362 | ||
1363 | /* If this is a jump to the test of a loop, it is likely true. We scan | |
1364 | forwards from the target label. If we find a NOTE_INSN_LOOP_VTOP | |
1365 | before the next real insn, we assume the branch is to the loop branch | |
1366 | test. */ | |
1367 | for (insn = NEXT_INSN (target_label); | |
1368 | insn && GET_CODE (insn) == NOTE; | |
1369 | insn = PREV_INSN (insn)) | |
1370 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP) | |
1371 | return 1; | |
4d0e69c3 | 1372 | } |
9c7e2978 | 1373 | |
0275a51b RK |
1374 | /* Look at the relative rarities of the fallthough and destination. If |
1375 | they differ, we can predict the branch that way. */ | |
9c7e2978 | 1376 | |
0275a51b RK |
1377 | switch (rare_fallthrough - rare_dest) |
1378 | { | |
1379 | case -2: | |
1380 | return -1; | |
1381 | case -1: | |
1382 | return 0; | |
1383 | case 0: | |
1384 | break; | |
1385 | case 1: | |
4d0e69c3 | 1386 | return 1; |
0275a51b RK |
1387 | case 2: |
1388 | return 2; | |
1389 | } | |
4d0e69c3 | 1390 | |
9c7e2978 RK |
1391 | /* If we couldn't figure out what this jump was, assume it won't be |
1392 | taken. This should be rare. */ | |
1393 | if (condition == 0) | |
1394 | return 0; | |
1395 | ||
1396 | /* EQ tests are usually false and NE tests are usually true. Also, | |
1397 | most quantities are positive, so we can make the appropriate guesses | |
1398 | about signed comparisons against zero. */ | |
1399 | switch (GET_CODE (condition)) | |
1400 | { | |
1401 | case CONST_INT: | |
1402 | /* Unconditional branch. */ | |
1403 | return 1; | |
1404 | case EQ: | |
1405 | return 0; | |
1406 | case NE: | |
1407 | return 1; | |
1408 | case LE: | |
1409 | case LT: | |
1410 | if (XEXP (condition, 1) == const0_rtx) | |
1411 | return 0; | |
1412 | break; | |
1413 | case GE: | |
1414 | case GT: | |
1415 | if (XEXP (condition, 1) == const0_rtx) | |
1416 | return 1; | |
1417 | break; | |
1418 | } | |
1419 | ||
1420 | /* Predict backward branches usually take, forward branches usually not. If | |
1421 | we don't know whether this is forward or backward, assume the branch | |
1422 | will be taken, since most are. */ | |
13b8df74 RK |
1423 | return (target_label == 0 || INSN_UID (jump_insn) > max_uid |
1424 | || INSN_UID (target_label) > max_uid | |
9c7e2978 RK |
1425 | || (uid_to_ruid[INSN_UID (jump_insn)] |
1426 | > uid_to_ruid[INSN_UID (target_label)]));; | |
1427 | } | |
1428 | ||
1429 | /* Return the condition under which INSN will branch to TARGET. If TARGET | |
1430 | is zero, return the condition under which INSN will return. If INSN is | |
1431 | an unconditional branch, return const_true_rtx. If INSN isn't a simple | |
1432 | type of jump, or it doesn't go to TARGET, return 0. */ | |
1433 | ||
1434 | static rtx | |
1435 | get_branch_condition (insn, target) | |
1436 | rtx insn; | |
1437 | rtx target; | |
1438 | { | |
1439 | rtx pat = PATTERN (insn); | |
1440 | rtx src; | |
1441 | ||
3480bb98 JL |
1442 | if (condjump_in_parallel_p (insn)) |
1443 | pat = XVECEXP (pat, 0, 0); | |
1444 | ||
9c7e2978 RK |
1445 | if (GET_CODE (pat) == RETURN) |
1446 | return target == 0 ? const_true_rtx : 0; | |
1447 | ||
1448 | else if (GET_CODE (pat) != SET || SET_DEST (pat) != pc_rtx) | |
1449 | return 0; | |
1450 | ||
1451 | src = SET_SRC (pat); | |
1452 | if (GET_CODE (src) == LABEL_REF && XEXP (src, 0) == target) | |
1453 | return const_true_rtx; | |
1454 | ||
1455 | else if (GET_CODE (src) == IF_THEN_ELSE | |
1456 | && ((target == 0 && GET_CODE (XEXP (src, 1)) == RETURN) | |
1457 | || (GET_CODE (XEXP (src, 1)) == LABEL_REF | |
1458 | && XEXP (XEXP (src, 1), 0) == target)) | |
1459 | && XEXP (src, 2) == pc_rtx) | |
1460 | return XEXP (src, 0); | |
1461 | ||
1462 | else if (GET_CODE (src) == IF_THEN_ELSE | |
1463 | && ((target == 0 && GET_CODE (XEXP (src, 2)) == RETURN) | |
1464 | || (GET_CODE (XEXP (src, 2)) == LABEL_REF | |
1465 | && XEXP (XEXP (src, 2), 0) == target)) | |
1466 | && XEXP (src, 1) == pc_rtx) | |
1467 | return gen_rtx (reverse_condition (GET_CODE (XEXP (src, 0))), | |
1468 | GET_MODE (XEXP (src, 0)), | |
1469 | XEXP (XEXP (src, 0), 0), XEXP (XEXP (src, 0), 1)); | |
58c8c593 RK |
1470 | |
1471 | return 0; | |
9c7e2978 RK |
1472 | } |
1473 | ||
1474 | /* Return non-zero if CONDITION is more strict than the condition of | |
1475 | INSN, i.e., if INSN will always branch if CONDITION is true. */ | |
1476 | ||
1477 | static int | |
1478 | condition_dominates_p (condition, insn) | |
1479 | rtx condition; | |
1480 | rtx insn; | |
1481 | { | |
1482 | rtx other_condition = get_branch_condition (insn, JUMP_LABEL (insn)); | |
1483 | enum rtx_code code = GET_CODE (condition); | |
1484 | enum rtx_code other_code; | |
1485 | ||
1486 | if (rtx_equal_p (condition, other_condition) | |
1487 | || other_condition == const_true_rtx) | |
1488 | return 1; | |
1489 | ||
1490 | else if (condition == const_true_rtx || other_condition == 0) | |
1491 | return 0; | |
1492 | ||
1493 | other_code = GET_CODE (other_condition); | |
1494 | if (GET_RTX_LENGTH (code) != 2 || GET_RTX_LENGTH (other_code) != 2 | |
1495 | || ! rtx_equal_p (XEXP (condition, 0), XEXP (other_condition, 0)) | |
1496 | || ! rtx_equal_p (XEXP (condition, 1), XEXP (other_condition, 1))) | |
1497 | return 0; | |
1498 | ||
1499 | return comparison_dominates_p (code, other_code); | |
1500 | } | |
83fd5651 JL |
1501 | |
1502 | /* Return non-zero if redirecting JUMP to NEWLABEL does not invalidate | |
1503 | any insns already in the delay slot of JUMP. */ | |
1504 | ||
1505 | static int | |
1506 | redirect_with_delay_slots_safe_p (jump, newlabel, seq) | |
1507 | rtx jump, newlabel, seq; | |
1508 | { | |
1509 | int flags, slots, i; | |
1510 | rtx pat = PATTERN (seq); | |
1511 | ||
1512 | /* Make sure all the delay slots of this jump would still | |
1513 | be valid after threading the jump. If they are still | |
1514 | valid, then return non-zero. */ | |
1515 | ||
1516 | flags = get_jump_flags (jump, newlabel); | |
1517 | for (i = 1; i < XVECLEN (pat, 0); i++) | |
1518 | if (! ( | |
1519 | #ifdef ANNUL_IFFALSE_SLOTS | |
1520 | (INSN_ANNULLED_BRANCH_P (jump) | |
1521 | && INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) | |
1522 | ? eligible_for_annul_false (jump, i - 1, | |
1523 | XVECEXP (pat, 0, i), flags) : | |
1524 | #endif | |
1525 | #ifdef ANNUL_IFTRUE_SLOTS | |
1526 | (INSN_ANNULLED_BRANCH_P (jump) | |
1527 | && ! INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) | |
1528 | ? eligible_for_annul_true (jump, i - 1, | |
1529 | XVECEXP (pat, 0, i), flags) : | |
1530 | #endif | |
1531 | eligible_for_delay (jump, i -1, XVECEXP (pat, 0, i), flags))) | |
1532 | break; | |
1533 | ||
1534 | return (i == XVECLEN (pat, 0)); | |
1535 | } | |
1536 | ||
b304ad47 JL |
1537 | /* Return non-zero if redirecting JUMP to NEWLABEL does not invalidate |
1538 | any insns we wish to place in the delay slot of JUMP. */ | |
1539 | ||
1540 | static int | |
1541 | redirect_with_delay_list_safe_p (jump, newlabel, delay_list) | |
1542 | rtx jump, newlabel, delay_list; | |
1543 | { | |
1544 | int flags, i; | |
1545 | rtx li; | |
1546 | ||
1547 | /* Make sure all the insns in DELAY_LIST would still be | |
1548 | valid after threading the jump. If they are still | |
1549 | valid, then return non-zero. */ | |
1550 | ||
1551 | flags = get_jump_flags (jump, newlabel); | |
1552 | for (li = delay_list, i = 0; li; li = XEXP (li, 1), i++) | |
1553 | if (! ( | |
1554 | #ifdef ANNUL_IFFALSE_SLOTS | |
1555 | (INSN_ANNULLED_BRANCH_P (jump) | |
1556 | && INSN_FROM_TARGET_P (XEXP (li, 0))) | |
4791d99b | 1557 | ? eligible_for_annul_false (jump, i, XEXP (li, 0), flags) : |
b304ad47 JL |
1558 | #endif |
1559 | #ifdef ANNUL_IFTRUE_SLOTS | |
1560 | (INSN_ANNULLED_BRANCH_P (jump) | |
1561 | && ! INSN_FROM_TARGET_P (XEXP (li, 0))) | |
4791d99b | 1562 | ? eligible_for_annul_true (jump, i, XEXP (li, 0), flags) : |
b304ad47 | 1563 | #endif |
4791d99b | 1564 | eligible_for_delay (jump, i, XEXP (li, 0), flags))) |
b304ad47 JL |
1565 | break; |
1566 | ||
1567 | return (li == NULL); | |
1568 | } | |
1569 | ||
9c7e2978 RK |
1570 | \f |
1571 | /* INSN branches to an insn whose pattern SEQ is a SEQUENCE. Given that | |
1572 | the condition tested by INSN is CONDITION and the resources shown in | |
1573 | OTHER_NEEDED are needed after INSN, see whether INSN can take all the insns | |
1574 | from SEQ's delay list, in addition to whatever insns it may execute | |
1575 | (in DELAY_LIST). SETS and NEEDED are denote resources already set and | |
1576 | needed while searching for delay slot insns. Return the concatenated | |
1577 | delay list if possible, otherwise, return 0. | |
1578 | ||
1579 | SLOTS_TO_FILL is the total number of slots required by INSN, and | |
1580 | PSLOTS_FILLED points to the number filled so far (also the number of | |
1581 | insns in DELAY_LIST). It is updated with the number that have been | |
1582 | filled from the SEQUENCE, if any. | |
1583 | ||
1584 | PANNUL_P points to a non-zero value if we already know that we need | |
1585 | to annul INSN. If this routine determines that annulling is needed, | |
1586 | it may set that value non-zero. | |
1587 | ||
1588 | PNEW_THREAD points to a location that is to receive the place at which | |
1589 | execution should continue. */ | |
1590 | ||
1591 | static rtx | |
1592 | steal_delay_list_from_target (insn, condition, seq, delay_list, | |
1593 | sets, needed, other_needed, | |
1594 | slots_to_fill, pslots_filled, pannul_p, | |
1595 | pnew_thread) | |
1596 | rtx insn, condition; | |
1597 | rtx seq; | |
1598 | rtx delay_list; | |
1599 | struct resources *sets, *needed, *other_needed; | |
1600 | int slots_to_fill; | |
1601 | int *pslots_filled; | |
1602 | int *pannul_p; | |
1603 | rtx *pnew_thread; | |
1604 | { | |
1605 | rtx temp; | |
1606 | int slots_remaining = slots_to_fill - *pslots_filled; | |
1607 | int total_slots_filled = *pslots_filled; | |
1608 | rtx new_delay_list = 0; | |
1609 | int must_annul = *pannul_p; | |
1610 | int i; | |
1611 | ||
1612 | /* We can't do anything if there are more delay slots in SEQ than we | |
1613 | can handle, or if we don't know that it will be a taken branch. | |
9c7e2978 | 1614 | We know that it will be a taken branch if it is either an unconditional |
fe41a98e JW |
1615 | branch or a conditional branch with a stricter branch condition. |
1616 | ||
1617 | Also, exit if the branch has more than one set, since then it is computing | |
1618 | other results that can't be ignored, e.g. the HPPA mov&branch instruction. | |
1619 | ??? It may be possible to move other sets into INSN in addition to | |
1620 | moving the instructions in the delay slots. */ | |
9c7e2978 RK |
1621 | |
1622 | if (XVECLEN (seq, 0) - 1 > slots_remaining | |
fe41a98e JW |
1623 | || ! condition_dominates_p (condition, XVECEXP (seq, 0, 0)) |
1624 | || ! single_set (XVECEXP (seq, 0, 0))) | |
9c7e2978 RK |
1625 | return delay_list; |
1626 | ||
1627 | for (i = 1; i < XVECLEN (seq, 0); i++) | |
1628 | { | |
1629 | rtx trial = XVECEXP (seq, 0, i); | |
35523fce | 1630 | int flags; |
9c7e2978 RK |
1631 | |
1632 | if (insn_references_resource_p (trial, sets, 0) | |
1633 | || insn_sets_resource_p (trial, needed, 0) | |
1634 | || insn_sets_resource_p (trial, sets, 0) | |
1635 | #ifdef HAVE_cc0 | |
1636 | /* If TRIAL sets CC0, we can't copy it, so we can't steal this | |
1637 | delay list. */ | |
fb3821f7 | 1638 | || find_reg_note (trial, REG_CC_USER, NULL_RTX) |
9c7e2978 RK |
1639 | #endif |
1640 | /* If TRIAL is from the fallthrough code of an annulled branch insn | |
1641 | in SEQ, we cannot use it. */ | |
1642 | || (INSN_ANNULLED_BRANCH_P (XVECEXP (seq, 0, 0)) | |
1643 | && ! INSN_FROM_TARGET_P (trial))) | |
1644 | return delay_list; | |
1645 | ||
1646 | /* If this insn was already done (usually in a previous delay slot), | |
1647 | pretend we put it in our delay slot. */ | |
f898abd7 | 1648 | if (redundant_insn (trial, insn, new_delay_list)) |
9c7e2978 RK |
1649 | continue; |
1650 | ||
35523fce JL |
1651 | /* We will end up re-vectoring this branch, so compute flags |
1652 | based on jumping to the new label. */ | |
1653 | flags = get_jump_flags (insn, JUMP_LABEL (XVECEXP (seq, 0, 0))); | |
1654 | ||
9c7e2978 RK |
1655 | if (! must_annul |
1656 | && ((condition == const_true_rtx | |
1657 | || (! insn_sets_resource_p (trial, other_needed, 0) | |
1658 | && ! may_trap_p (PATTERN (trial))))) | |
35523fce | 1659 | ? eligible_for_delay (insn, total_slots_filled, trial, flags) |
9c7e2978 | 1660 | : (must_annul = 1, |
35523fce | 1661 | eligible_for_annul_false (insn, total_slots_filled, trial, flags))) |
9c7e2978 RK |
1662 | { |
1663 | temp = copy_rtx (trial); | |
1664 | INSN_FROM_TARGET_P (temp) = 1; | |
1665 | new_delay_list = add_to_delay_list (temp, new_delay_list); | |
1666 | total_slots_filled++; | |
1667 | ||
1668 | if (--slots_remaining == 0) | |
1669 | break; | |
1670 | } | |
1671 | else | |
1672 | return delay_list; | |
1673 | } | |
1674 | ||
1675 | /* Show the place to which we will be branching. */ | |
1676 | *pnew_thread = next_active_insn (JUMP_LABEL (XVECEXP (seq, 0, 0))); | |
1677 | ||
1678 | /* Add any new insns to the delay list and update the count of the | |
1679 | number of slots filled. */ | |
1680 | *pslots_filled = total_slots_filled; | |
1681 | *pannul_p = must_annul; | |
1682 | ||
1683 | if (delay_list == 0) | |
1684 | return new_delay_list; | |
1685 | ||
1686 | for (temp = new_delay_list; temp; temp = XEXP (temp, 1)) | |
1687 | delay_list = add_to_delay_list (XEXP (temp, 0), delay_list); | |
1688 | ||
1689 | return delay_list; | |
1690 | } | |
1691 | \f | |
1692 | /* Similar to steal_delay_list_from_target except that SEQ is on the | |
1693 | fallthrough path of INSN. Here we only do something if the delay insn | |
1694 | of SEQ is an unconditional branch. In that case we steal its delay slot | |
1695 | for INSN since unconditional branches are much easier to fill. */ | |
1696 | ||
1697 | static rtx | |
1698 | steal_delay_list_from_fallthrough (insn, condition, seq, | |
1699 | delay_list, sets, needed, other_needed, | |
1700 | slots_to_fill, pslots_filled, pannul_p) | |
1701 | rtx insn, condition; | |
1702 | rtx seq; | |
1703 | rtx delay_list; | |
1704 | struct resources *sets, *needed, *other_needed; | |
1705 | int slots_to_fill; | |
1706 | int *pslots_filled; | |
1707 | int *pannul_p; | |
1708 | { | |
1709 | int i; | |
35523fce JL |
1710 | int flags; |
1711 | ||
1712 | flags = get_jump_flags (insn, JUMP_LABEL (insn)); | |
9c7e2978 RK |
1713 | |
1714 | /* We can't do anything if SEQ's delay insn isn't an | |
1715 | unconditional branch. */ | |
1716 | ||
1717 | if (! simplejump_p (XVECEXP (seq, 0, 0)) | |
1718 | && GET_CODE (PATTERN (XVECEXP (seq, 0, 0))) != RETURN) | |
1719 | return delay_list; | |
1720 | ||
1721 | for (i = 1; i < XVECLEN (seq, 0); i++) | |
1722 | { | |
1723 | rtx trial = XVECEXP (seq, 0, i); | |
1724 | ||
1725 | /* If TRIAL sets CC0, stealing it will move it too far from the use | |
1726 | of CC0. */ | |
1727 | if (insn_references_resource_p (trial, sets, 0) | |
1728 | || insn_sets_resource_p (trial, needed, 0) | |
1729 | || insn_sets_resource_p (trial, sets, 0) | |
1730 | #ifdef HAVE_cc0 | |
1731 | || sets_cc0_p (PATTERN (trial)) | |
1732 | #endif | |
1733 | ) | |
1734 | ||
1735 | break; | |
1736 | ||
1737 | /* If this insn was already done, we don't need it. */ | |
f898abd7 | 1738 | if (redundant_insn (trial, insn, delay_list)) |
9c7e2978 RK |
1739 | { |
1740 | delete_from_delay_slot (trial); | |
1741 | continue; | |
1742 | } | |
1743 | ||
1744 | if (! *pannul_p | |
1745 | && ((condition == const_true_rtx | |
1746 | || (! insn_sets_resource_p (trial, other_needed, 0) | |
1747 | && ! may_trap_p (PATTERN (trial))))) | |
35523fce | 1748 | ? eligible_for_delay (insn, *pslots_filled, trial, flags) |
9c7e2978 | 1749 | : (*pannul_p = 1, |
35523fce | 1750 | eligible_for_annul_true (insn, *pslots_filled, trial, flags))) |
9c7e2978 RK |
1751 | { |
1752 | delete_from_delay_slot (trial); | |
1753 | delay_list = add_to_delay_list (trial, delay_list); | |
1754 | ||
1755 | if (++(*pslots_filled) == slots_to_fill) | |
1756 | break; | |
1757 | } | |
1758 | else | |
1759 | break; | |
1760 | } | |
1761 | ||
1762 | return delay_list; | |
1763 | } | |
1764 | \f | |
1765 | /* Try merging insns starting at THREAD which match exactly the insns in | |
1766 | INSN's delay list. | |
1767 | ||
1768 | If all insns were matched and the insn was previously annulling, the | |
1769 | annul bit will be cleared. | |
1770 | ||
1771 | For each insn that is merged, if the branch is or will be non-annulling, | |
1772 | we delete the merged insn. */ | |
1773 | ||
1774 | static void | |
1775 | try_merge_delay_insns (insn, thread) | |
1776 | rtx insn, thread; | |
1777 | { | |
1778 | rtx trial, next_trial; | |
1779 | rtx delay_insn = XVECEXP (PATTERN (insn), 0, 0); | |
1780 | int annul_p = INSN_ANNULLED_BRANCH_P (delay_insn); | |
1781 | int slot_number = 1; | |
1782 | int num_slots = XVECLEN (PATTERN (insn), 0); | |
1783 | rtx next_to_match = XVECEXP (PATTERN (insn), 0, slot_number); | |
1784 | struct resources set, needed; | |
1785 | rtx merged_insns = 0; | |
1786 | int i; | |
35523fce JL |
1787 | int flags; |
1788 | ||
a2f54138 | 1789 | flags = get_jump_flags (delay_insn, JUMP_LABEL (delay_insn)); |
9c7e2978 RK |
1790 | |
1791 | CLEAR_RESOURCE (&needed); | |
1792 | CLEAR_RESOURCE (&set); | |
1793 | ||
1794 | /* If this is not an annulling branch, take into account anything needed in | |
1795 | NEXT_TO_MATCH. This prevents two increments from being incorrectly | |
1796 | folded into one. If we are annulling, this would be the correct | |
1797 | thing to do. (The alternative, looking at things set in NEXT_TO_MATCH | |
1798 | will essentially disable this optimization. This method is somewhat of | |
1799 | a kludge, but I don't see a better way.) */ | |
1800 | if (! annul_p) | |
1801 | mark_referenced_resources (next_to_match, &needed, 1); | |
1802 | ||
1803 | for (trial = thread; !stop_search_p (trial, 1); trial = next_trial) | |
1804 | { | |
1805 | rtx pat = PATTERN (trial); | |
ce15adaa | 1806 | rtx oldtrial = trial; |
9c7e2978 RK |
1807 | |
1808 | next_trial = next_nonnote_insn (trial); | |
1809 | ||
1810 | /* TRIAL must be a CALL_INSN or INSN. Skip USE and CLOBBER. */ | |
1811 | if (GET_CODE (trial) == INSN | |
1812 | && (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)) | |
1813 | continue; | |
1814 | ||
1815 | if (GET_CODE (next_to_match) == GET_CODE (trial) | |
1816 | #ifdef HAVE_cc0 | |
1817 | /* We can't share an insn that sets cc0. */ | |
1818 | && ! sets_cc0_p (pat) | |
1819 | #endif | |
1820 | && ! insn_references_resource_p (trial, &set, 1) | |
1821 | && ! insn_sets_resource_p (trial, &set, 1) | |
1822 | && ! insn_sets_resource_p (trial, &needed, 1) | |
1823 | && (trial = try_split (pat, trial, 0)) != 0 | |
9772d94f JW |
1824 | /* Update next_trial, in case try_split succeeded. */ |
1825 | && (next_trial = next_nonnote_insn (trial)) | |
ce15adaa RK |
1826 | /* Likewise THREAD. */ |
1827 | && (thread = oldtrial == thread ? trial : thread) | |
9c7e2978 RK |
1828 | && rtx_equal_p (PATTERN (next_to_match), PATTERN (trial)) |
1829 | /* Have to test this condition if annul condition is different | |
1830 | from (and less restrictive than) non-annulling one. */ | |
35523fce | 1831 | && eligible_for_delay (delay_insn, slot_number - 1, trial, flags)) |
9c7e2978 | 1832 | { |
9c7e2978 RK |
1833 | |
1834 | if (! annul_p) | |
1835 | { | |
f1f9081a | 1836 | update_block (trial, thread); |
8ad4abfc RK |
1837 | if (trial == thread) |
1838 | thread = next_active_insn (thread); | |
1839 | ||
9c7e2978 RK |
1840 | delete_insn (trial); |
1841 | INSN_FROM_TARGET_P (next_to_match) = 0; | |
1842 | } | |
1843 | else | |
1844 | merged_insns = gen_rtx (INSN_LIST, VOIDmode, trial, merged_insns); | |
1845 | ||
1846 | if (++slot_number == num_slots) | |
1847 | break; | |
1848 | ||
1849 | next_to_match = XVECEXP (PATTERN (insn), 0, slot_number); | |
1850 | if (! annul_p) | |
1851 | mark_referenced_resources (next_to_match, &needed, 1); | |
1852 | } | |
1853 | ||
26d970a5 | 1854 | mark_set_resources (trial, &set, 0, 1); |
9c7e2978 RK |
1855 | mark_referenced_resources (trial, &needed, 1); |
1856 | } | |
1857 | ||
1858 | /* See if we stopped on a filled insn. If we did, try to see if its | |
1859 | delay slots match. */ | |
1860 | if (slot_number != num_slots | |
1861 | && trial && GET_CODE (trial) == INSN | |
1862 | && GET_CODE (PATTERN (trial)) == SEQUENCE | |
1863 | && ! INSN_ANNULLED_BRANCH_P (XVECEXP (PATTERN (trial), 0, 0))) | |
1864 | { | |
1865 | rtx pat = PATTERN (trial); | |
058acefd JW |
1866 | rtx filled_insn = XVECEXP (pat, 0, 0); |
1867 | ||
1868 | /* Account for resources set/needed by the filled insn. */ | |
1869 | mark_set_resources (filled_insn, &set, 0, 1); | |
1870 | mark_referenced_resources (filled_insn, &needed, 1); | |
9c7e2978 RK |
1871 | |
1872 | for (i = 1; i < XVECLEN (pat, 0); i++) | |
1873 | { | |
1874 | rtx dtrial = XVECEXP (pat, 0, i); | |
1875 | ||
1876 | if (! insn_references_resource_p (dtrial, &set, 1) | |
1877 | && ! insn_sets_resource_p (dtrial, &set, 1) | |
1878 | && ! insn_sets_resource_p (dtrial, &needed, 1) | |
1879 | #ifdef HAVE_cc0 | |
1880 | && ! sets_cc0_p (PATTERN (dtrial)) | |
1881 | #endif | |
1882 | && rtx_equal_p (PATTERN (next_to_match), PATTERN (dtrial)) | |
35523fce | 1883 | && eligible_for_delay (delay_insn, slot_number - 1, dtrial, flags)) |
9c7e2978 RK |
1884 | { |
1885 | if (! annul_p) | |
1886 | { | |
f1f9081a | 1887 | update_block (dtrial, thread); |
9c7e2978 RK |
1888 | delete_from_delay_slot (dtrial); |
1889 | INSN_FROM_TARGET_P (next_to_match) = 0; | |
1890 | } | |
1891 | else | |
1892 | merged_insns = gen_rtx (INSN_LIST, SImode, dtrial, | |
1893 | merged_insns); | |
1894 | ||
1895 | if (++slot_number == num_slots) | |
1896 | break; | |
1897 | ||
1898 | next_to_match = XVECEXP (PATTERN (insn), 0, slot_number); | |
1899 | } | |
1900 | } | |
1901 | } | |
1902 | ||
1903 | /* If all insns in the delay slot have been matched and we were previously | |
1904 | annulling the branch, we need not any more. In that case delete all the | |
1905 | merged insns. Also clear the INSN_FROM_TARGET_P bit of each insn the | |
1906 | the delay list so that we know that it isn't only being used at the | |
1907 | target. */ | |
d58b6986 | 1908 | if (slot_number == num_slots && annul_p) |
9c7e2978 RK |
1909 | { |
1910 | for (; merged_insns; merged_insns = XEXP (merged_insns, 1)) | |
1911 | { | |
1912 | if (GET_MODE (merged_insns) == SImode) | |
1913 | { | |
f1f9081a | 1914 | update_block (XEXP (merged_insns, 0), thread); |
9c7e2978 RK |
1915 | delete_from_delay_slot (XEXP (merged_insns, 0)); |
1916 | } | |
1917 | else | |
1918 | { | |
f1f9081a | 1919 | update_block (XEXP (merged_insns, 0), thread); |
9c7e2978 RK |
1920 | delete_insn (XEXP (merged_insns, 0)); |
1921 | } | |
1922 | } | |
1923 | ||
1924 | INSN_ANNULLED_BRANCH_P (delay_insn) = 0; | |
1925 | ||
1926 | for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++) | |
1927 | INSN_FROM_TARGET_P (XVECEXP (PATTERN (insn), 0, i)) = 0; | |
1928 | } | |
1929 | } | |
1930 | \f | |
1931 | /* See if INSN is redundant with an insn in front of TARGET. Often this | |
1932 | is called when INSN is a candidate for a delay slot of TARGET. | |
1933 | DELAY_LIST are insns that will be placed in delay slots of TARGET in front | |
1934 | of INSN. Often INSN will be redundant with an insn in a delay slot of | |
1935 | some previous insn. This happens when we have a series of branches to the | |
1936 | same label; in that case the first insn at the target might want to go | |
1937 | into each of the delay slots. | |
1938 | ||
1939 | If we are not careful, this routine can take up a significant fraction | |
1940 | of the total compilation time (4%), but only wins rarely. Hence we | |
1941 | speed this routine up by making two passes. The first pass goes back | |
1942 | until it hits a label and sees if it find an insn with an identical | |
1943 | pattern. Only in this (relatively rare) event does it check for | |
1944 | data conflicts. | |
1945 | ||
1946 | We do not split insns we encounter. This could cause us not to find a | |
1947 | redundant insn, but the cost of splitting seems greater than the possible | |
1948 | gain in rare cases. */ | |
1949 | ||
5317d2f8 | 1950 | static rtx |
f898abd7 | 1951 | redundant_insn (insn, target, delay_list) |
9c7e2978 RK |
1952 | rtx insn; |
1953 | rtx target; | |
1954 | rtx delay_list; | |
1955 | { | |
1956 | rtx target_main = target; | |
1957 | rtx ipat = PATTERN (insn); | |
1958 | rtx trial, pat; | |
1959 | struct resources needed, set; | |
1960 | int i; | |
1961 | ||
1962 | /* Scan backwards looking for a match. */ | |
1963 | for (trial = PREV_INSN (target); trial; trial = PREV_INSN (trial)) | |
1964 | { | |
1965 | if (GET_CODE (trial) == CODE_LABEL) | |
1966 | return 0; | |
1967 | ||
009f6146 | 1968 | if (GET_RTX_CLASS (GET_CODE (trial)) != 'i') |
9c7e2978 RK |
1969 | continue; |
1970 | ||
1971 | pat = PATTERN (trial); | |
1972 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
1973 | continue; | |
1974 | ||
1975 | if (GET_CODE (pat) == SEQUENCE) | |
1976 | { | |
ca104c13 JL |
1977 | /* Stop for a CALL and its delay slots because it is difficult to |
1978 | track its resource needs correctly. */ | |
9c7e2978 RK |
1979 | if (GET_CODE (XVECEXP (pat, 0, 0)) == CALL_INSN) |
1980 | return 0; | |
1981 | ||
ca104c13 JL |
1982 | /* Stop for an INSN or JUMP_INSN with delayed effects and its delay |
1983 | slots because it is difficult to track its resource needs | |
1984 | correctly. */ | |
1985 | ||
1986 | #ifdef INSN_SETS_ARE_DELAYED | |
1987 | if (INSN_SETS_ARE_DELAYED (XVECEXP (pat, 0, 0))) | |
1988 | return 0; | |
1989 | #endif | |
1990 | ||
1991 | #ifdef INSN_REFERENCES_ARE_DELAYED | |
1992 | if (INSN_REFERENCES_ARE_DELAYED (XVECEXP (pat, 0, 0))) | |
1993 | return 0; | |
1994 | #endif | |
1995 | ||
1996 | /* See if any of the insns in the delay slot match, updating | |
1997 | resource requirements as we go. */ | |
9c7e2978 RK |
1998 | for (i = XVECLEN (pat, 0) - 1; i > 0; i--) |
1999 | if (GET_CODE (XVECEXP (pat, 0, i)) == GET_CODE (insn) | |
2000 | && rtx_equal_p (PATTERN (XVECEXP (pat, 0, i)), ipat)) | |
2001 | break; | |
2002 | ||
2003 | /* If found a match, exit this loop early. */ | |
2004 | if (i > 0) | |
2005 | break; | |
2006 | } | |
2007 | ||
2008 | else if (GET_CODE (trial) == GET_CODE (insn) && rtx_equal_p (pat, ipat)) | |
2009 | break; | |
2010 | } | |
2011 | ||
2012 | /* If we didn't find an insn that matches, return 0. */ | |
2013 | if (trial == 0) | |
2014 | return 0; | |
2015 | ||
2016 | /* See what resources this insn sets and needs. If they overlap, or | |
2017 | if this insn references CC0, it can't be redundant. */ | |
2018 | ||
2019 | CLEAR_RESOURCE (&needed); | |
2020 | CLEAR_RESOURCE (&set); | |
26d970a5 | 2021 | mark_set_resources (insn, &set, 0, 1); |
9c7e2978 RK |
2022 | mark_referenced_resources (insn, &needed, 1); |
2023 | ||
2024 | /* If TARGET is a SEQUENCE, get the main insn. */ | |
2025 | if (GET_CODE (target) == INSN && GET_CODE (PATTERN (target)) == SEQUENCE) | |
2026 | target_main = XVECEXP (PATTERN (target), 0, 0); | |
2027 | ||
2028 | if (resource_conflicts_p (&needed, &set) | |
2029 | #ifdef HAVE_cc0 | |
2030 | || reg_mentioned_p (cc0_rtx, ipat) | |
2031 | #endif | |
2032 | /* The insn requiring the delay may not set anything needed or set by | |
2033 | INSN. */ | |
2034 | || insn_sets_resource_p (target_main, &needed, 1) | |
2035 | || insn_sets_resource_p (target_main, &set, 1)) | |
2036 | return 0; | |
2037 | ||
2038 | /* Insns we pass may not set either NEEDED or SET, so merge them for | |
2039 | simpler tests. */ | |
2040 | needed.memory |= set.memory; | |
8eae5ed6 | 2041 | needed.unch_memory |= set.unch_memory; |
9c7e2978 RK |
2042 | IOR_HARD_REG_SET (needed.regs, set.regs); |
2043 | ||
2044 | /* This insn isn't redundant if it conflicts with an insn that either is | |
2045 | or will be in a delay slot of TARGET. */ | |
2046 | ||
2047 | while (delay_list) | |
2048 | { | |
2049 | if (insn_sets_resource_p (XEXP (delay_list, 0), &needed, 1)) | |
2050 | return 0; | |
2051 | delay_list = XEXP (delay_list, 1); | |
2052 | } | |
2053 | ||
2054 | if (GET_CODE (target) == INSN && GET_CODE (PATTERN (target)) == SEQUENCE) | |
2055 | for (i = 1; i < XVECLEN (PATTERN (target), 0); i++) | |
2056 | if (insn_sets_resource_p (XVECEXP (PATTERN (target), 0, i), &needed, 1)) | |
2057 | return 0; | |
2058 | ||
2059 | /* Scan backwards until we reach a label or an insn that uses something | |
2060 | INSN sets or sets something insn uses or sets. */ | |
2061 | ||
2062 | for (trial = PREV_INSN (target); | |
2063 | trial && GET_CODE (trial) != CODE_LABEL; | |
2064 | trial = PREV_INSN (trial)) | |
2065 | { | |
2066 | if (GET_CODE (trial) != INSN && GET_CODE (trial) != CALL_INSN | |
2067 | && GET_CODE (trial) != JUMP_INSN) | |
2068 | continue; | |
2069 | ||
2070 | pat = PATTERN (trial); | |
2071 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
2072 | continue; | |
2073 | ||
2074 | if (GET_CODE (pat) == SEQUENCE) | |
2075 | { | |
2076 | /* If this is a CALL_INSN and its delay slots, it is hard to track | |
2077 | the resource needs properly, so give up. */ | |
2078 | if (GET_CODE (XVECEXP (pat, 0, 0)) == CALL_INSN) | |
2079 | return 0; | |
2080 | ||
ca104c13 JL |
2081 | /* If this this is an INSN or JUMP_INSN with delayed effects, it |
2082 | is hard to track the resource needs properly, so give up. */ | |
2083 | ||
2084 | #ifdef INSN_SETS_ARE_DELAYED | |
2085 | if (INSN_SETS_ARE_DELAYED (XVECEXP (pat, 0, 0))) | |
2086 | return 0; | |
2087 | #endif | |
2088 | ||
2089 | #ifdef INSN_REFERENCES_ARE_DELAYED | |
2090 | if (INSN_REFERENCES_ARE_DELAYED (XVECEXP (pat, 0, 0))) | |
2091 | return 0; | |
2092 | #endif | |
2093 | ||
9c7e2978 RK |
2094 | /* See if any of the insns in the delay slot match, updating |
2095 | resource requirements as we go. */ | |
2096 | for (i = XVECLEN (pat, 0) - 1; i > 0; i--) | |
2097 | { | |
2098 | rtx candidate = XVECEXP (pat, 0, i); | |
2099 | ||
2100 | /* If an insn will be annulled if the branch is false, it isn't | |
2101 | considered as a possible duplicate insn. */ | |
2102 | if (rtx_equal_p (PATTERN (candidate), ipat) | |
2103 | && ! (INSN_ANNULLED_BRANCH_P (XVECEXP (pat, 0, 0)) | |
2104 | && INSN_FROM_TARGET_P (candidate))) | |
2105 | { | |
2106 | /* Show that this insn will be used in the sequel. */ | |
2107 | INSN_FROM_TARGET_P (candidate) = 0; | |
5317d2f8 | 2108 | return candidate; |
9c7e2978 RK |
2109 | } |
2110 | ||
2111 | /* Unless this is an annulled insn from the target of a branch, | |
2112 | we must stop if it sets anything needed or set by INSN. */ | |
2113 | if ((! INSN_ANNULLED_BRANCH_P (XVECEXP (pat, 0, 0)) | |
2114 | || ! INSN_FROM_TARGET_P (candidate)) | |
2115 | && insn_sets_resource_p (candidate, &needed, 1)) | |
2116 | return 0; | |
2117 | } | |
2118 | ||
2119 | ||
2120 | /* If the insn requiring the delay slot conflicts with INSN, we | |
2121 | must stop. */ | |
2122 | if (insn_sets_resource_p (XVECEXP (pat, 0, 0), &needed, 1)) | |
2123 | return 0; | |
2124 | } | |
2125 | else | |
2126 | { | |
2127 | /* See if TRIAL is the same as INSN. */ | |
2128 | pat = PATTERN (trial); | |
2129 | if (rtx_equal_p (pat, ipat)) | |
5317d2f8 | 2130 | return trial; |
9c7e2978 RK |
2131 | |
2132 | /* Can't go any further if TRIAL conflicts with INSN. */ | |
2133 | if (insn_sets_resource_p (trial, &needed, 1)) | |
2134 | return 0; | |
2135 | } | |
2136 | } | |
2137 | ||
2138 | return 0; | |
2139 | } | |
2140 | \f | |
2141 | /* Return 1 if THREAD can only be executed in one way. If LABEL is non-zero, | |
2142 | it is the target of the branch insn being scanned. If ALLOW_FALLTHROUGH | |
2143 | is non-zero, we are allowed to fall into this thread; otherwise, we are | |
2144 | not. | |
2145 | ||
2146 | If LABEL is used more than one or we pass a label other than LABEL before | |
2147 | finding an active insn, we do not own this thread. */ | |
2148 | ||
2149 | static int | |
2150 | own_thread_p (thread, label, allow_fallthrough) | |
2151 | rtx thread; | |
2152 | rtx label; | |
2153 | int allow_fallthrough; | |
2154 | { | |
2155 | rtx active_insn; | |
2156 | rtx insn; | |
2157 | ||
2158 | /* We don't own the function end. */ | |
2159 | if (thread == 0) | |
2160 | return 0; | |
2161 | ||
2162 | /* Get the first active insn, or THREAD, if it is an active insn. */ | |
2163 | active_insn = next_active_insn (PREV_INSN (thread)); | |
2164 | ||
2165 | for (insn = thread; insn != active_insn; insn = NEXT_INSN (insn)) | |
2166 | if (GET_CODE (insn) == CODE_LABEL | |
2167 | && (insn != label || LABEL_NUSES (insn) != 1)) | |
2168 | return 0; | |
2169 | ||
2170 | if (allow_fallthrough) | |
2171 | return 1; | |
2172 | ||
2173 | /* Ensure that we reach a BARRIER before any insn or label. */ | |
2174 | for (insn = prev_nonnote_insn (thread); | |
2175 | insn == 0 || GET_CODE (insn) != BARRIER; | |
2176 | insn = prev_nonnote_insn (insn)) | |
2177 | if (insn == 0 | |
2178 | || GET_CODE (insn) == CODE_LABEL | |
2179 | || (GET_CODE (insn) == INSN | |
2180 | && GET_CODE (PATTERN (insn)) != USE | |
2181 | && GET_CODE (PATTERN (insn)) != CLOBBER)) | |
2182 | return 0; | |
2183 | ||
2184 | return 1; | |
2185 | } | |
2186 | \f | |
2187 | /* Find the number of the basic block that starts closest to INSN. Return -1 | |
2188 | if we couldn't find such a basic block. */ | |
2189 | ||
2190 | static int | |
2191 | find_basic_block (insn) | |
2192 | rtx insn; | |
2193 | { | |
2194 | int i; | |
2195 | ||
2196 | /* Scan backwards to the previous BARRIER. Then see if we can find a | |
2197 | label that starts a basic block. Return the basic block number. */ | |
2198 | ||
2199 | for (insn = prev_nonnote_insn (insn); | |
2200 | insn && GET_CODE (insn) != BARRIER; | |
2201 | insn = prev_nonnote_insn (insn)) | |
2202 | ; | |
2203 | ||
2204 | /* The start of the function is basic block zero. */ | |
2205 | if (insn == 0) | |
2206 | return 0; | |
2207 | ||
2208 | /* See if any of the upcoming CODE_LABELs start a basic block. If we reach | |
2209 | anything other than a CODE_LABEL or note, we can't find this code. */ | |
2210 | for (insn = next_nonnote_insn (insn); | |
2211 | insn && GET_CODE (insn) == CODE_LABEL; | |
2212 | insn = next_nonnote_insn (insn)) | |
2213 | { | |
2214 | for (i = 0; i < n_basic_blocks; i++) | |
2215 | if (insn == basic_block_head[i]) | |
2216 | return i; | |
2217 | } | |
2218 | ||
2219 | return -1; | |
2220 | } | |
2221 | \f | |
9c7e2978 | 2222 | /* Called when INSN is being moved from a location near the target of a jump. |
aa2c50d6 | 2223 | We leave a marker of the form (use (INSN)) immediately in front |
9c7e2978 | 2224 | of WHERE for mark_target_live_regs. These markers will be deleted when |
aa2c50d6 RK |
2225 | reorg finishes. |
2226 | ||
2227 | We used to try to update the live status of registers if WHERE is at | |
2228 | the start of a basic block, but that can't work since we may remove a | |
2229 | BARRIER in relax_delay_slots. */ | |
9c7e2978 RK |
2230 | |
2231 | static void | |
2232 | update_block (insn, where) | |
2233 | rtx insn; | |
2234 | rtx where; | |
2235 | { | |
aa2c50d6 RK |
2236 | int b; |
2237 | ||
9c7e2978 RK |
2238 | /* Ignore if this was in a delay slot and it came from the target of |
2239 | a branch. */ | |
2240 | if (INSN_FROM_TARGET_P (insn)) | |
2241 | return; | |
2242 | ||
aa2c50d6 | 2243 | emit_insn_before (gen_rtx (USE, VOIDmode, insn), where); |
9c7e2978 RK |
2244 | |
2245 | /* INSN might be making a value live in a block where it didn't use to | |
2246 | be. So recompute liveness information for this block. */ | |
aa2c50d6 RK |
2247 | |
2248 | b = find_basic_block (insn); | |
2249 | if (b != -1) | |
2250 | bb_ticks[b]++; | |
9c7e2978 | 2251 | } |
28c9500b | 2252 | |
326f06f7 RK |
2253 | /* Similar to REDIRECT_JUMP except that we update the BB_TICKS entry for |
2254 | the basic block containing the jump. */ | |
2255 | ||
2256 | static int | |
2257 | reorg_redirect_jump (jump, nlabel) | |
2258 | rtx jump; | |
2259 | rtx nlabel; | |
2260 | { | |
2261 | int b = find_basic_block (jump); | |
2262 | ||
2263 | if (b != -1) | |
2264 | bb_ticks[b]++; | |
2265 | ||
2266 | return redirect_jump (jump, nlabel); | |
2267 | } | |
2268 | ||
28c9500b JW |
2269 | /* Called when INSN is being moved forward into a delay slot of DELAYED_INSN. |
2270 | We check every instruction between INSN and DELAYED_INSN for REG_DEAD notes | |
2271 | that reference values used in INSN. If we find one, then we move the | |
2272 | REG_DEAD note to INSN. | |
2273 | ||
2274 | This is needed to handle the case where an later insn (after INSN) has a | |
2275 | REG_DEAD note for a register used by INSN, and this later insn subsequently | |
2276 | gets moved before a CODE_LABEL because it is a redundant insn. In this | |
2277 | case, mark_target_live_regs may be confused into thinking the register | |
2278 | is dead because it sees a REG_DEAD note immediately before a CODE_LABEL. */ | |
2279 | ||
2280 | static void | |
2281 | update_reg_dead_notes (insn, delayed_insn) | |
2282 | rtx insn, delayed_insn; | |
2283 | { | |
2284 | rtx p, link, next; | |
2285 | ||
2286 | for (p = next_nonnote_insn (insn); p != delayed_insn; | |
2287 | p = next_nonnote_insn (p)) | |
2288 | for (link = REG_NOTES (p); link; link = next) | |
2289 | { | |
2290 | next = XEXP (link, 1); | |
2291 | ||
2292 | if (REG_NOTE_KIND (link) != REG_DEAD | |
2293 | || GET_CODE (XEXP (link, 0)) != REG) | |
2294 | continue; | |
2295 | ||
2296 | if (reg_referenced_p (XEXP (link, 0), PATTERN (insn))) | |
2297 | { | |
2298 | /* Move the REG_DEAD note from P to INSN. */ | |
2299 | remove_note (p, link); | |
2300 | XEXP (link, 1) = REG_NOTES (insn); | |
2301 | REG_NOTES (insn) = link; | |
2302 | } | |
2303 | } | |
2304 | } | |
5317d2f8 RK |
2305 | |
2306 | /* Delete any REG_UNUSED notes that exist on INSN but not on REDUNDANT_INSN. | |
2307 | ||
2308 | This handles the case of udivmodXi4 instructions which optimize their | |
2309 | output depending on whether any REG_UNUSED notes are present. | |
2310 | we must make sure that INSN calculates as many results as REDUNDANT_INSN | |
2311 | does. */ | |
2312 | ||
2313 | static void | |
2314 | update_reg_unused_notes (insn, redundant_insn) | |
2315 | rtx insn, redundant_insn; | |
2316 | { | |
2317 | rtx p, link, next; | |
2318 | ||
2319 | for (link = REG_NOTES (insn); link; link = next) | |
2320 | { | |
2321 | next = XEXP (link, 1); | |
2322 | ||
2323 | if (REG_NOTE_KIND (link) != REG_UNUSED | |
2324 | || GET_CODE (XEXP (link, 0)) != REG) | |
2325 | continue; | |
2326 | ||
2327 | if (! find_regno_note (redundant_insn, REG_UNUSED, | |
2328 | REGNO (XEXP (link, 0)))) | |
2329 | remove_note (insn, link); | |
2330 | } | |
2331 | } | |
9c7e2978 RK |
2332 | \f |
2333 | /* Marks registers possibly live at the current place being scanned by | |
2334 | mark_target_live_regs. Used only by next two function. */ | |
2335 | ||
2336 | static HARD_REG_SET current_live_regs; | |
2337 | ||
2338 | /* Marks registers for which we have seen a REG_DEAD note but no assignment. | |
2339 | Also only used by the next two functions. */ | |
2340 | ||
2341 | static HARD_REG_SET pending_dead_regs; | |
2342 | ||
2343 | /* Utility function called from mark_target_live_regs via note_stores. | |
2344 | It deadens any CLOBBERed registers and livens any SET registers. */ | |
2345 | ||
2346 | static void | |
2347 | update_live_status (dest, x) | |
2348 | rtx dest; | |
2349 | rtx x; | |
2350 | { | |
2351 | int first_regno, last_regno; | |
2352 | int i; | |
2353 | ||
2354 | if (GET_CODE (dest) != REG | |
2355 | && (GET_CODE (dest) != SUBREG || GET_CODE (SUBREG_REG (dest)) != REG)) | |
2356 | return; | |
2357 | ||
2358 | if (GET_CODE (dest) == SUBREG) | |
2359 | first_regno = REGNO (SUBREG_REG (dest)) + SUBREG_WORD (dest); | |
2360 | else | |
2361 | first_regno = REGNO (dest); | |
2362 | ||
2363 | last_regno = first_regno + HARD_REGNO_NREGS (first_regno, GET_MODE (dest)); | |
2364 | ||
2365 | if (GET_CODE (x) == CLOBBER) | |
2366 | for (i = first_regno; i < last_regno; i++) | |
2367 | CLEAR_HARD_REG_BIT (current_live_regs, i); | |
2368 | else | |
2369 | for (i = first_regno; i < last_regno; i++) | |
2370 | { | |
2371 | SET_HARD_REG_BIT (current_live_regs, i); | |
2372 | CLEAR_HARD_REG_BIT (pending_dead_regs, i); | |
2373 | } | |
2374 | } | |
2375 | ||
2376 | /* Similar to next_insn, but ignores insns in the delay slots of | |
2377 | an annulled branch. */ | |
2378 | ||
2379 | static rtx | |
2380 | next_insn_no_annul (insn) | |
2381 | rtx insn; | |
2382 | { | |
2383 | if (insn) | |
2384 | { | |
2385 | /* If INSN is an annulled branch, skip any insns from the target | |
2386 | of the branch. */ | |
2387 | if (INSN_ANNULLED_BRANCH_P (insn) | |
2388 | && NEXT_INSN (PREV_INSN (insn)) != insn) | |
2389 | while (INSN_FROM_TARGET_P (NEXT_INSN (insn))) | |
2390 | insn = NEXT_INSN (insn); | |
2391 | ||
2392 | insn = NEXT_INSN (insn); | |
2393 | if (insn && GET_CODE (insn) == INSN | |
2394 | && GET_CODE (PATTERN (insn)) == SEQUENCE) | |
2395 | insn = XVECEXP (PATTERN (insn), 0, 0); | |
2396 | } | |
2397 | ||
2398 | return insn; | |
2399 | } | |
2400 | \f | |
2401 | /* Set the resources that are live at TARGET. | |
2402 | ||
2403 | If TARGET is zero, we refer to the end of the current function and can | |
2404 | return our precomputed value. | |
2405 | ||
2406 | Otherwise, we try to find out what is live by consulting the basic block | |
2407 | information. This is tricky, because we must consider the actions of | |
2408 | reload and jump optimization, which occur after the basic block information | |
2409 | has been computed. | |
2410 | ||
2411 | Accordingly, we proceed as follows:: | |
2412 | ||
2413 | We find the previous BARRIER and look at all immediately following labels | |
2414 | (with no intervening active insns) to see if any of them start a basic | |
2415 | block. If we hit the start of the function first, we use block 0. | |
2416 | ||
2417 | Once we have found a basic block and a corresponding first insns, we can | |
2418 | accurately compute the live status from basic_block_live_regs and | |
2419 | reg_renumber. (By starting at a label following a BARRIER, we are immune | |
2420 | to actions taken by reload and jump.) Then we scan all insns between | |
2421 | that point and our target. For each CLOBBER (or for call-clobbered regs | |
2422 | when we pass a CALL_INSN), mark the appropriate registers are dead. For | |
2423 | a SET, mark them as live. | |
2424 | ||
2425 | We have to be careful when using REG_DEAD notes because they are not | |
2426 | updated by such things as find_equiv_reg. So keep track of registers | |
2427 | marked as dead that haven't been assigned to, and mark them dead at the | |
2428 | next CODE_LABEL since reload and jump won't propagate values across labels. | |
2429 | ||
2430 | If we cannot find the start of a basic block (should be a very rare | |
2431 | case, if it can happen at all), mark everything as potentially live. | |
2432 | ||
2433 | Next, scan forward from TARGET looking for things set or clobbered | |
2434 | before they are used. These are not live. | |
2435 | ||
2436 | Because we can be called many times on the same target, save our results | |
2437 | in a hash table indexed by INSN_UID. */ | |
2438 | ||
2439 | static void | |
2440 | mark_target_live_regs (target, res) | |
2441 | rtx target; | |
2442 | struct resources *res; | |
2443 | { | |
2444 | int b = -1; | |
2445 | int i; | |
2446 | struct target_info *tinfo; | |
2447 | rtx insn, next; | |
2448 | rtx jump_insn = 0; | |
464b453d | 2449 | rtx jump_target; |
9c7e2978 RK |
2450 | HARD_REG_SET scratch; |
2451 | struct resources set, needed; | |
2452 | int jump_count = 0; | |
2453 | ||
2454 | /* Handle end of function. */ | |
2455 | if (target == 0) | |
2456 | { | |
2457 | *res = end_of_function_needs; | |
2458 | return; | |
2459 | } | |
2460 | ||
2461 | /* We have to assume memory is needed, but the CC isn't. */ | |
2462 | res->memory = 1; | |
8eae5ed6 | 2463 | res->volatil = res->unch_memory = 0; |
9c7e2978 RK |
2464 | res->cc = 0; |
2465 | ||
2466 | /* See if we have computed this value already. */ | |
2467 | for (tinfo = target_hash_table[INSN_UID (target) % TARGET_HASH_PRIME]; | |
2468 | tinfo; tinfo = tinfo->next) | |
2469 | if (tinfo->uid == INSN_UID (target)) | |
2470 | break; | |
2471 | ||
2472 | /* Start by getting the basic block number. If we have saved information, | |
2473 | we can get it from there unless the insn at the start of the basic block | |
2474 | has been deleted. */ | |
2475 | if (tinfo && tinfo->block != -1 | |
2476 | && ! INSN_DELETED_P (basic_block_head[tinfo->block])) | |
2477 | b = tinfo->block; | |
2478 | ||
2479 | if (b == -1) | |
2480 | b = find_basic_block (target); | |
2481 | ||
2482 | if (tinfo) | |
2483 | { | |
2484 | /* If the information is up-to-date, use it. Otherwise, we will | |
2485 | update it below. */ | |
2486 | if (b == tinfo->block && b != -1 && tinfo->bb_tick == bb_ticks[b]) | |
2487 | { | |
2488 | COPY_HARD_REG_SET (res->regs, tinfo->live_regs); | |
2489 | return; | |
2490 | } | |
2491 | } | |
2492 | else | |
2493 | { | |
2494 | /* Allocate a place to put our results and chain it into the | |
2495 | hash table. */ | |
2496 | tinfo = (struct target_info *) oballoc (sizeof (struct target_info)); | |
2497 | tinfo->uid = INSN_UID (target); | |
2498 | tinfo->block = b; | |
2499 | tinfo->next = target_hash_table[INSN_UID (target) % TARGET_HASH_PRIME]; | |
2500 | target_hash_table[INSN_UID (target) % TARGET_HASH_PRIME] = tinfo; | |
2501 | } | |
2502 | ||
2503 | CLEAR_HARD_REG_SET (pending_dead_regs); | |
2504 | ||
2505 | /* If we found a basic block, get the live registers from it and update | |
2506 | them with anything set or killed between its start and the insn before | |
2507 | TARGET. Otherwise, we must assume everything is live. */ | |
2508 | if (b != -1) | |
2509 | { | |
2510 | regset regs_live = basic_block_live_at_start[b]; | |
fb3821f7 CH |
2511 | int offset, j; |
2512 | REGSET_ELT_TYPE bit; | |
9c7e2978 RK |
2513 | int regno; |
2514 | rtx start_insn, stop_insn; | |
2515 | ||
2516 | /* Compute hard regs live at start of block -- this is the real hard regs | |
2517 | marked live, plus live pseudo regs that have been renumbered to | |
2518 | hard regs. */ | |
2519 | ||
69887ad9 RK |
2520 | #ifdef HARD_REG_SET |
2521 | current_live_regs = *regs_live; | |
2522 | #else | |
2523 | COPY_HARD_REG_SET (current_live_regs, regs_live); | |
2524 | #endif | |
9c7e2978 RK |
2525 | |
2526 | for (offset = 0, i = 0; offset < regset_size; offset++) | |
2527 | { | |
2528 | if (regs_live[offset] == 0) | |
fb3821f7 | 2529 | i += REGSET_ELT_BITS; |
9c7e2978 RK |
2530 | else |
2531 | for (bit = 1; bit && i < max_regno; bit <<= 1, i++) | |
2532 | if ((regs_live[offset] & bit) | |
2533 | && (regno = reg_renumber[i]) >= 0) | |
2534 | for (j = regno; | |
2535 | j < regno + HARD_REGNO_NREGS (regno, | |
2536 | PSEUDO_REGNO_MODE (i)); | |
2537 | j++) | |
2538 | SET_HARD_REG_BIT (current_live_regs, j); | |
2539 | } | |
2540 | ||
2541 | /* Get starting and ending insn, handling the case where each might | |
2542 | be a SEQUENCE. */ | |
2543 | start_insn = (b == 0 ? get_insns () : basic_block_head[b]); | |
2544 | stop_insn = target; | |
2545 | ||
2546 | if (GET_CODE (start_insn) == INSN | |
2547 | && GET_CODE (PATTERN (start_insn)) == SEQUENCE) | |
2548 | start_insn = XVECEXP (PATTERN (start_insn), 0, 0); | |
2549 | ||
2550 | if (GET_CODE (stop_insn) == INSN | |
2551 | && GET_CODE (PATTERN (stop_insn)) == SEQUENCE) | |
2552 | stop_insn = next_insn (PREV_INSN (stop_insn)); | |
2553 | ||
2554 | for (insn = start_insn; insn != stop_insn; | |
2555 | insn = next_insn_no_annul (insn)) | |
2556 | { | |
2557 | rtx link; | |
2558 | rtx real_insn = insn; | |
2559 | ||
2560 | /* If this insn is from the target of a branch, it isn't going to | |
2561 | be used in the sequel. If it is used in both cases, this | |
2562 | test will not be true. */ | |
2563 | if (INSN_FROM_TARGET_P (insn)) | |
2564 | continue; | |
2565 | ||
2566 | /* If this insn is a USE made by update_block, we care about the | |
2567 | underlying insn. */ | |
2568 | if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == USE | |
1422dce0 | 2569 | && GET_RTX_CLASS (GET_CODE (XEXP (PATTERN (insn), 0))) == 'i') |
9c7e2978 RK |
2570 | real_insn = XEXP (PATTERN (insn), 0); |
2571 | ||
2572 | if (GET_CODE (real_insn) == CALL_INSN) | |
2573 | { | |
2574 | /* CALL clobbers all call-used regs that aren't fixed except | |
2575 | sp, ap, and fp. Do this before setting the result of the | |
2576 | call live. */ | |
2577 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
6e7348c1 | 2578 | if (call_used_regs[i] |
9c7e2978 | 2579 | && i != STACK_POINTER_REGNUM && i != FRAME_POINTER_REGNUM |
6e7348c1 | 2580 | && i != ARG_POINTER_REGNUM |
b07ff75d DE |
2581 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM |
2582 | && i != HARD_FRAME_POINTER_REGNUM | |
2583 | #endif | |
6e7348c1 RK |
2584 | #if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM |
2585 | && ! (i == ARG_POINTER_REGNUM && fixed_regs[i]) | |
2586 | #endif | |
2587 | #ifdef PIC_OFFSET_TABLE_REGNUM | |
2588 | && ! (i == PIC_OFFSET_TABLE_REGNUM && flag_pic) | |
2589 | #endif | |
2590 | ) | |
9c7e2978 | 2591 | CLEAR_HARD_REG_BIT (current_live_regs, i); |
a419da61 RK |
2592 | |
2593 | /* A CALL_INSN sets any global register live, since it may | |
2594 | have been modified by the call. */ | |
2595 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
2596 | if (global_regs[i]) | |
2597 | SET_HARD_REG_BIT (current_live_regs, i); | |
9c7e2978 RK |
2598 | } |
2599 | ||
2600 | /* Mark anything killed in an insn to be deadened at the next | |
2601 | label. Ignore USE insns; the only REG_DEAD notes will be for | |
2602 | parameters. But they might be early. A CALL_INSN will usually | |
2603 | clobber registers used for parameters. It isn't worth bothering | |
2604 | with the unlikely case when it won't. */ | |
2605 | if ((GET_CODE (real_insn) == INSN | |
f87ef537 JW |
2606 | && GET_CODE (PATTERN (real_insn)) != USE |
2607 | && GET_CODE (PATTERN (real_insn)) != CLOBBER) | |
9c7e2978 RK |
2608 | || GET_CODE (real_insn) == JUMP_INSN |
2609 | || GET_CODE (real_insn) == CALL_INSN) | |
2610 | { | |
2611 | for (link = REG_NOTES (real_insn); link; link = XEXP (link, 1)) | |
2612 | if (REG_NOTE_KIND (link) == REG_DEAD | |
2613 | && GET_CODE (XEXP (link, 0)) == REG | |
2614 | && REGNO (XEXP (link, 0)) < FIRST_PSEUDO_REGISTER) | |
2615 | { | |
2616 | int first_regno = REGNO (XEXP (link, 0)); | |
2617 | int last_regno | |
2618 | = (first_regno | |
2619 | + HARD_REGNO_NREGS (first_regno, | |
2620 | GET_MODE (XEXP (link, 0)))); | |
2621 | ||
2622 | for (i = first_regno; i < last_regno; i++) | |
2623 | SET_HARD_REG_BIT (pending_dead_regs, i); | |
2624 | } | |
2625 | ||
2626 | note_stores (PATTERN (real_insn), update_live_status); | |
2627 | ||
2628 | /* If any registers were unused after this insn, kill them. | |
2629 | These notes will always be accurate. */ | |
2630 | for (link = REG_NOTES (real_insn); link; link = XEXP (link, 1)) | |
2631 | if (REG_NOTE_KIND (link) == REG_UNUSED | |
2632 | && GET_CODE (XEXP (link, 0)) == REG | |
2633 | && REGNO (XEXP (link, 0)) < FIRST_PSEUDO_REGISTER) | |
2634 | { | |
2635 | int first_regno = REGNO (XEXP (link, 0)); | |
2636 | int last_regno | |
2637 | = (first_regno | |
2638 | + HARD_REGNO_NREGS (first_regno, | |
2639 | GET_MODE (XEXP (link, 0)))); | |
2640 | ||
2641 | for (i = first_regno; i < last_regno; i++) | |
2642 | CLEAR_HARD_REG_BIT (current_live_regs, i); | |
2643 | } | |
2644 | } | |
2645 | ||
7bd80f37 | 2646 | else if (GET_CODE (real_insn) == CODE_LABEL) |
9c7e2978 RK |
2647 | { |
2648 | /* A label clobbers the pending dead registers since neither | |
2649 | reload nor jump will propagate a value across a label. */ | |
2650 | AND_COMPL_HARD_REG_SET (current_live_regs, pending_dead_regs); | |
2651 | CLEAR_HARD_REG_SET (pending_dead_regs); | |
2652 | } | |
7bd80f37 TW |
2653 | |
2654 | /* The beginning of the epilogue corresponds to the end of the | |
2655 | RTL chain when there are no epilogue insns. Certain resources | |
2656 | are implicitly required at that point. */ | |
2657 | else if (GET_CODE (real_insn) == NOTE | |
2658 | && NOTE_LINE_NUMBER (real_insn) == NOTE_INSN_EPILOGUE_BEG) | |
2659 | IOR_HARD_REG_SET (current_live_regs, start_of_epilogue_needs.regs); | |
9c7e2978 RK |
2660 | } |
2661 | ||
2662 | COPY_HARD_REG_SET (res->regs, current_live_regs); | |
2663 | tinfo->block = b; | |
2664 | tinfo->bb_tick = bb_ticks[b]; | |
2665 | } | |
2666 | else | |
2667 | /* We didn't find the start of a basic block. Assume everything | |
2668 | in use. This should happen only extremely rarely. */ | |
2669 | SET_HARD_REG_SET (res->regs); | |
2670 | ||
2671 | /* Now step forward from TARGET looking for registers that are set before | |
2672 | they are used. These are dead. If we pass a label, any pending dead | |
2673 | registers that weren't yet used can be made dead. Stop when we pass a | |
2674 | conditional JUMP_INSN; follow the first few unconditional branches. */ | |
2675 | ||
2676 | CLEAR_RESOURCE (&set); | |
2677 | CLEAR_RESOURCE (&needed); | |
2678 | ||
2679 | for (insn = target; insn; insn = next) | |
2680 | { | |
464b453d | 2681 | rtx this_jump_insn = insn; |
9c7e2978 RK |
2682 | |
2683 | next = NEXT_INSN (insn); | |
2684 | switch (GET_CODE (insn)) | |
2685 | { | |
2686 | case CODE_LABEL: | |
2687 | AND_COMPL_HARD_REG_SET (pending_dead_regs, needed.regs); | |
2688 | AND_COMPL_HARD_REG_SET (res->regs, pending_dead_regs); | |
2689 | CLEAR_HARD_REG_SET (pending_dead_regs); | |
2690 | continue; | |
2691 | ||
2692 | case BARRIER: | |
2693 | case NOTE: | |
2694 | continue; | |
2695 | ||
2696 | case INSN: | |
1422dce0 RK |
2697 | if (GET_CODE (PATTERN (insn)) == USE) |
2698 | { | |
2699 | /* If INSN is a USE made by update_block, we care about the | |
014830a5 RK |
2700 | underlying insn. Any registers set by the underlying insn |
2701 | are live since the insn is being done somewhere else. */ | |
1422dce0 | 2702 | if (GET_RTX_CLASS (GET_CODE (XEXP (PATTERN (insn), 0))) == 'i') |
014830a5 | 2703 | mark_set_resources (XEXP (PATTERN (insn), 0), res, 0, 1); |
1422dce0 RK |
2704 | |
2705 | /* All other USE insns are to be ignored. */ | |
2706 | continue; | |
2707 | } | |
2708 | else if (GET_CODE (PATTERN (insn)) == CLOBBER) | |
9c7e2978 | 2709 | continue; |
1422dce0 | 2710 | else if (GET_CODE (PATTERN (insn)) == SEQUENCE) |
464b453d TW |
2711 | { |
2712 | /* An unconditional jump can be used to fill the delay slot | |
2713 | of a call, so search for a JUMP_INSN in any position. */ | |
2714 | for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++) | |
2715 | { | |
2716 | this_jump_insn = XVECEXP (PATTERN (insn), 0, i); | |
2717 | if (GET_CODE (this_jump_insn) == JUMP_INSN) | |
2718 | break; | |
2719 | } | |
2720 | } | |
9c7e2978 RK |
2721 | } |
2722 | ||
464b453d | 2723 | if (GET_CODE (this_jump_insn) == JUMP_INSN) |
9c7e2978 RK |
2724 | { |
2725 | if (jump_count++ < 10 | |
464b453d TW |
2726 | && (simplejump_p (this_jump_insn) |
2727 | || GET_CODE (PATTERN (this_jump_insn)) == RETURN)) | |
9c7e2978 | 2728 | { |
464b453d | 2729 | next = next_active_insn (JUMP_LABEL (this_jump_insn)); |
9c7e2978 | 2730 | if (jump_insn == 0) |
464b453d TW |
2731 | { |
2732 | jump_insn = insn; | |
2733 | jump_target = JUMP_LABEL (this_jump_insn); | |
2734 | } | |
9c7e2978 RK |
2735 | } |
2736 | else | |
2737 | break; | |
2738 | } | |
2739 | ||
2740 | mark_referenced_resources (insn, &needed, 1); | |
26d970a5 | 2741 | mark_set_resources (insn, &set, 0, 1); |
9c7e2978 RK |
2742 | |
2743 | COPY_HARD_REG_SET (scratch, set.regs); | |
2744 | AND_COMPL_HARD_REG_SET (scratch, needed.regs); | |
2745 | AND_COMPL_HARD_REG_SET (res->regs, scratch); | |
2746 | } | |
2747 | ||
2748 | /* If we hit an unconditional branch, we have another way of finding out | |
2749 | what is live: we can see what is live at the branch target and include | |
2750 | anything used but not set before the branch. The only things that are | |
98ccf8fe RK |
2751 | live are those that are live using the above test and the test below. |
2752 | ||
2753 | Don't try this if we expired our jump count above, since that would | |
2754 | mean there may be an infinite loop in the function being compiled. */ | |
2755 | ||
2756 | if (jump_insn && jump_count < 10) | |
9c7e2978 | 2757 | { |
9c7e2978 RK |
2758 | struct resources new_resources; |
2759 | rtx stop_insn = next_active_insn (jump_insn); | |
2760 | ||
2761 | mark_target_live_regs (next_active_insn (jump_target), &new_resources); | |
2762 | CLEAR_RESOURCE (&set); | |
2763 | CLEAR_RESOURCE (&needed); | |
2764 | ||
2765 | /* Include JUMP_INSN in the needed registers. */ | |
2766 | for (insn = target; insn != stop_insn; insn = next_active_insn (insn)) | |
2767 | { | |
2768 | mark_referenced_resources (insn, &needed, 1); | |
2769 | ||
2770 | COPY_HARD_REG_SET (scratch, needed.regs); | |
2771 | AND_COMPL_HARD_REG_SET (scratch, set.regs); | |
2772 | IOR_HARD_REG_SET (new_resources.regs, scratch); | |
2773 | ||
26d970a5 | 2774 | mark_set_resources (insn, &set, 0, 1); |
9c7e2978 RK |
2775 | } |
2776 | ||
2777 | AND_HARD_REG_SET (res->regs, new_resources.regs); | |
2778 | } | |
2779 | ||
2780 | COPY_HARD_REG_SET (tinfo->live_regs, res->regs); | |
2781 | } | |
2782 | \f | |
2783 | /* Scan a function looking for insns that need a delay slot and find insns to | |
2784 | put into the delay slot. | |
2785 | ||
2786 | NON_JUMPS_P is non-zero if we are to only try to fill non-jump insns (such | |
2787 | as calls). We do these first since we don't want jump insns (that are | |
2788 | easier to fill) to get the only insns that could be used for non-jump insns. | |
2789 | When it is zero, only try to fill JUMP_INSNs. | |
2790 | ||
2791 | When slots are filled in this manner, the insns (including the | |
2792 | delay_insn) are put together in a SEQUENCE rtx. In this fashion, | |
2793 | it is possible to tell whether a delay slot has really been filled | |
2794 | or not. `final' knows how to deal with this, by communicating | |
2795 | through FINAL_SEQUENCE. */ | |
2796 | ||
2797 | static void | |
2798 | fill_simple_delay_slots (first, non_jumps_p) | |
2799 | rtx first; | |
d8e8f346 | 2800 | int non_jumps_p; |
9c7e2978 RK |
2801 | { |
2802 | register rtx insn, pat, trial, next_trial; | |
464b453d | 2803 | register int i, j; |
9c7e2978 RK |
2804 | int num_unfilled_slots = unfilled_slots_next - unfilled_slots_base; |
2805 | struct resources needed, set; | |
2806 | register int slots_to_fill, slots_filled; | |
2807 | rtx delay_list; | |
2808 | ||
2809 | for (i = 0; i < num_unfilled_slots; i++) | |
2810 | { | |
35523fce | 2811 | int flags; |
9c7e2978 RK |
2812 | /* Get the next insn to fill. If it has already had any slots assigned, |
2813 | we can't do anything with it. Maybe we'll improve this later. */ | |
2814 | ||
2815 | insn = unfilled_slots_base[i]; | |
2816 | if (insn == 0 | |
2817 | || INSN_DELETED_P (insn) | |
2818 | || (GET_CODE (insn) == INSN | |
2819 | && GET_CODE (PATTERN (insn)) == SEQUENCE) | |
2820 | || (GET_CODE (insn) == JUMP_INSN && non_jumps_p) | |
2821 | || (GET_CODE (insn) != JUMP_INSN && ! non_jumps_p)) | |
2822 | continue; | |
35523fce | 2823 | |
a2f54138 JL |
2824 | if (GET_CODE (insn) == JUMP_INSN) |
2825 | flags = get_jump_flags (insn, JUMP_LABEL (insn)); | |
2826 | else | |
2827 | flags = get_jump_flags (insn, NULL_RTX); | |
9c7e2978 RK |
2828 | slots_to_fill = num_delay_slots (insn); |
2829 | if (slots_to_fill == 0) | |
2830 | abort (); | |
2831 | ||
2832 | /* This insn needs, or can use, some delay slots. SLOTS_TO_FILL | |
464b453d TW |
2833 | says how many. After initialization, first try optimizing |
2834 | ||
2835 | call _foo call _foo | |
2836 | nop add %o7,.-L1,%o7 | |
2837 | b,a L1 | |
2838 | nop | |
2839 | ||
2840 | If this case applies, the delay slot of the call is filled with | |
2841 | the unconditional jump. This is done first to avoid having the | |
2842 | delay slot of the call filled in the backward scan. Also, since | |
2843 | the unconditional jump is likely to also have a delay slot, that | |
733fa7ef JL |
2844 | insn must exist when it is subsequently scanned. |
2845 | ||
2846 | This is tried on each insn with delay slots as some machines | |
2847 | have insns which perform calls, but are not represented as | |
2848 | CALL_INSNs. */ | |
464b453d TW |
2849 | |
2850 | slots_filled = 0; | |
2851 | delay_list = 0; | |
2852 | ||
733fa7ef | 2853 | if ((trial = next_active_insn (insn)) |
464b453d TW |
2854 | && GET_CODE (trial) == JUMP_INSN |
2855 | && simplejump_p (trial) | |
35523fce | 2856 | && eligible_for_delay (insn, slots_filled, trial, flags) |
464b453d TW |
2857 | && no_labels_between_p (insn, trial)) |
2858 | { | |
2859 | slots_filled++; | |
2860 | delay_list = add_to_delay_list (trial, delay_list); | |
2861 | /* Remove the unconditional jump from consideration for delay slot | |
2862 | filling and unthread it. */ | |
2863 | if (unfilled_slots_base[i + 1] == trial) | |
2864 | unfilled_slots_base[i + 1] = 0; | |
2865 | { | |
2866 | rtx next = NEXT_INSN (trial); | |
2867 | rtx prev = PREV_INSN (trial); | |
2868 | if (prev) | |
2869 | NEXT_INSN (prev) = next; | |
2870 | if (next) | |
2871 | PREV_INSN (next) = prev; | |
2872 | } | |
2873 | } | |
2874 | ||
2875 | /* Now, scan backwards from the insn to search for a potential | |
2876 | delay-slot candidate. Stop searching when a label or jump is hit. | |
2877 | ||
9c7e2978 RK |
2878 | For each candidate, if it is to go into the delay slot (moved |
2879 | forward in execution sequence), it must not need or set any resources | |
2880 | that were set by later insns and must not set any resources that | |
2881 | are needed for those insns. | |
2882 | ||
2883 | The delay slot insn itself sets resources unless it is a call | |
2884 | (in which case the called routine, not the insn itself, is doing | |
2885 | the setting). */ | |
2886 | ||
464b453d | 2887 | if (slots_filled < slots_to_fill) |
9c7e2978 | 2888 | { |
464b453d TW |
2889 | CLEAR_RESOURCE (&needed); |
2890 | CLEAR_RESOURCE (&set); | |
2891 | mark_set_resources (insn, &set, 0, 0); | |
2892 | mark_referenced_resources (insn, &needed, 0); | |
9c7e2978 | 2893 | |
464b453d TW |
2894 | for (trial = prev_nonnote_insn (insn); ! stop_search_p (trial, 1); |
2895 | trial = next_trial) | |
2896 | { | |
2897 | next_trial = prev_nonnote_insn (trial); | |
9c7e2978 | 2898 | |
464b453d TW |
2899 | /* This must be an INSN or CALL_INSN. */ |
2900 | pat = PATTERN (trial); | |
2901 | ||
2902 | /* USE and CLOBBER at this level was just for flow; ignore it. */ | |
2903 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
2904 | continue; | |
9c7e2978 | 2905 | |
464b453d TW |
2906 | /* Check for resource conflict first, to avoid unnecessary |
2907 | splitting. */ | |
2908 | if (! insn_references_resource_p (trial, &set, 1) | |
2909 | && ! insn_sets_resource_p (trial, &set, 1) | |
2910 | && ! insn_sets_resource_p (trial, &needed, 1) | |
9c7e2978 | 2911 | #ifdef HAVE_cc0 |
464b453d TW |
2912 | /* Can't separate set of cc0 from its use. */ |
2913 | && ! (reg_mentioned_p (cc0_rtx, pat) | |
2914 | && ! sets_cc0_p (cc0_rtx, pat)) | |
9c7e2978 | 2915 | #endif |
464b453d | 2916 | ) |
9c7e2978 | 2917 | { |
464b453d TW |
2918 | trial = try_split (pat, trial, 1); |
2919 | next_trial = prev_nonnote_insn (trial); | |
35523fce | 2920 | if (eligible_for_delay (insn, slots_filled, trial, flags)) |
464b453d TW |
2921 | { |
2922 | /* In this case, we are searching backward, so if we | |
2923 | find insns to put on the delay list, we want | |
2924 | to put them at the head, rather than the | |
2925 | tail, of the list. */ | |
2926 | ||
28c9500b | 2927 | update_reg_dead_notes (trial, insn); |
464b453d TW |
2928 | delay_list = gen_rtx (INSN_LIST, VOIDmode, |
2929 | trial, delay_list); | |
2930 | update_block (trial, trial); | |
2931 | delete_insn (trial); | |
2932 | if (slots_to_fill == ++slots_filled) | |
2933 | break; | |
2934 | continue; | |
2935 | } | |
9c7e2978 | 2936 | } |
9c7e2978 | 2937 | |
464b453d TW |
2938 | mark_set_resources (trial, &set, 0, 1); |
2939 | mark_referenced_resources (trial, &needed, 1); | |
2940 | } | |
9c7e2978 RK |
2941 | } |
2942 | ||
9c7e2978 RK |
2943 | /* If all needed slots haven't been filled, we come here. */ |
2944 | ||
2945 | /* Try to optimize case of jumping around a single insn. */ | |
2946 | #if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS) | |
2f9ba5a9 JL |
2947 | if (slots_filled != slots_to_fill |
2948 | && delay_list == 0 | |
3480bb98 JL |
2949 | && GET_CODE (insn) == JUMP_INSN |
2950 | && (condjump_p (insn) || condjump_in_parallel_p (insn))) | |
9c7e2978 RK |
2951 | { |
2952 | delay_list = optimize_skip (insn); | |
2953 | if (delay_list) | |
2954 | slots_filled += 1; | |
2955 | } | |
2956 | #endif | |
2957 | ||
9c7e2978 RK |
2958 | /* Try to get insns from beyond the insn needing the delay slot. |
2959 | These insns can neither set or reference resources set in insns being | |
2960 | skipped, cannot set resources in the insn being skipped, and, if this | |
2961 | is a CALL_INSN (or a CALL_INSN is passed), cannot trap (because the | |
2962 | call might not return). | |
2963 | ||
2964 | If this is a conditional jump, see if it merges back to us early | |
2965 | enough for us to pick up insns from the merge point. Don't do | |
2966 | this if there is another branch to our label unless we pass all of | |
2967 | them. | |
2968 | ||
2969 | Another similar merge is if we jump to the same place that a | |
2970 | later unconditional jump branches to. In that case, we don't | |
2971 | care about the number of uses of our label. */ | |
2972 | ||
2f9ba5a9 JL |
2973 | if (slots_filled != slots_to_fill |
2974 | && (GET_CODE (insn) != JUMP_INSN | |
3480bb98 JL |
2975 | || ((condjump_p (insn) || condjump_in_parallel_p (insn)) |
2976 | && ! simplejump_p (insn) | |
2f9ba5a9 | 2977 | && JUMP_LABEL (insn) != 0))) |
9c7e2978 RK |
2978 | { |
2979 | rtx target = 0; | |
2980 | int maybe_never = 0; | |
2981 | int passed_label = 0; | |
2982 | int target_uses; | |
2983 | struct resources needed_at_jump; | |
2984 | ||
2985 | CLEAR_RESOURCE (&needed); | |
2986 | CLEAR_RESOURCE (&set); | |
2987 | ||
2988 | if (GET_CODE (insn) == CALL_INSN) | |
2989 | { | |
26d970a5 | 2990 | mark_set_resources (insn, &set, 0, 1); |
9c7e2978 RK |
2991 | mark_referenced_resources (insn, &needed, 1); |
2992 | maybe_never = 1; | |
2993 | } | |
2f9ba5a9 | 2994 | else |
9c7e2978 | 2995 | { |
674345b1 JL |
2996 | mark_set_resources (insn, &set, 0, 1); |
2997 | mark_referenced_resources (insn, &needed, 1); | |
2f9ba5a9 JL |
2998 | if (GET_CODE (insn) == JUMP_INSN) |
2999 | { | |
3000 | /* Get our target and show how many more uses we want to | |
3001 | see before we hit the label. */ | |
3002 | target = JUMP_LABEL (insn); | |
3003 | target_uses = LABEL_NUSES (target) - 1; | |
3004 | } | |
3005 | ||
9c7e2978 RK |
3006 | } |
3007 | ||
3008 | for (trial = next_nonnote_insn (insn); trial; trial = next_trial) | |
3009 | { | |
3010 | rtx pat, trial_delay; | |
3011 | ||
3012 | next_trial = next_nonnote_insn (trial); | |
3013 | ||
3014 | if (GET_CODE (trial) == CODE_LABEL) | |
3015 | { | |
3016 | passed_label = 1; | |
3017 | ||
3018 | /* If this is our target, see if we have seen all its uses. | |
3019 | If so, indicate we have passed our target and ignore it. | |
3020 | All other labels cause us to stop our search. */ | |
3021 | if (trial == target && target_uses == 0) | |
3022 | { | |
3023 | target = 0; | |
3024 | continue; | |
3025 | } | |
3026 | else | |
3027 | break; | |
3028 | } | |
3029 | else if (GET_CODE (trial) == BARRIER) | |
3030 | break; | |
3031 | ||
3032 | /* We must have an INSN, JUMP_INSN, or CALL_INSN. */ | |
3033 | pat = PATTERN (trial); | |
3034 | ||
3035 | /* Stand-alone USE and CLOBBER are just for flow. */ | |
3036 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
3037 | continue; | |
3038 | ||
3039 | /* If this already has filled delay slots, get the insn needing | |
3040 | the delay slots. */ | |
3041 | if (GET_CODE (pat) == SEQUENCE) | |
3042 | trial_delay = XVECEXP (pat, 0, 0); | |
3043 | else | |
3044 | trial_delay = trial; | |
3045 | ||
3046 | /* If this is a jump insn to our target, indicate that we have | |
3047 | seen another jump to it. If we aren't handling a conditional | |
3048 | jump, stop our search. Otherwise, compute the needs at its | |
3049 | target and add them to NEEDED. */ | |
3050 | if (GET_CODE (trial_delay) == JUMP_INSN) | |
3051 | { | |
3052 | if (target == 0) | |
3053 | break; | |
3054 | else if (JUMP_LABEL (trial_delay) == target) | |
3055 | target_uses--; | |
3056 | else | |
3057 | { | |
3058 | mark_target_live_regs | |
3059 | (next_active_insn (JUMP_LABEL (trial_delay)), | |
3060 | &needed_at_jump); | |
3061 | needed.memory |= needed_at_jump.memory; | |
8eae5ed6 | 3062 | needed.unch_memory |= needed_at_jump.unch_memory; |
9c7e2978 RK |
3063 | IOR_HARD_REG_SET (needed.regs, needed_at_jump.regs); |
3064 | } | |
3065 | } | |
3066 | ||
3067 | /* See if we have a resource problem before we try to | |
3068 | split. */ | |
3069 | if (target == 0 | |
3070 | && GET_CODE (pat) != SEQUENCE | |
3071 | && ! insn_references_resource_p (trial, &set, 1) | |
3072 | && ! insn_sets_resource_p (trial, &set, 1) | |
3073 | && ! insn_sets_resource_p (trial, &needed, 1) | |
3074 | #ifdef HAVE_cc0 | |
3075 | && ! (reg_mentioned_p (cc0_rtx, pat) && ! sets_cc0_p (pat)) | |
3076 | #endif | |
3077 | && ! (maybe_never && may_trap_p (pat)) | |
3078 | && (trial = try_split (pat, trial, 0)) | |
35523fce | 3079 | && eligible_for_delay (insn, slots_filled, trial, flags)) |
9c7e2978 RK |
3080 | { |
3081 | next_trial = next_nonnote_insn (trial); | |
3082 | delay_list = add_to_delay_list (trial, delay_list); | |
3083 | ||
3084 | #ifdef HAVE_cc0 | |
3085 | if (reg_mentioned_p (cc0_rtx, pat)) | |
3086 | link_cc0_insns (trial); | |
3087 | #endif | |
3088 | ||
3089 | if (passed_label) | |
3090 | update_block (trial, trial); | |
3091 | delete_insn (trial); | |
3092 | if (slots_to_fill == ++slots_filled) | |
3093 | break; | |
3094 | continue; | |
3095 | } | |
3096 | ||
26d970a5 | 3097 | mark_set_resources (trial, &set, 0, 1); |
9c7e2978 RK |
3098 | mark_referenced_resources (trial, &needed, 1); |
3099 | ||
3100 | /* Ensure we don't put insns between the setting of cc and the | |
3101 | comparison by moving a setting of cc into an earlier delay | |
3102 | slot since these insns could clobber the condition code. */ | |
3103 | set.cc = 1; | |
3104 | ||
3105 | /* If this is a call or jump, we might not get here. */ | |
3106 | if (GET_CODE (trial) == CALL_INSN | |
3107 | || GET_CODE (trial) == JUMP_INSN) | |
3108 | maybe_never = 1; | |
3109 | } | |
3110 | ||
3111 | /* If there are slots left to fill and our search was stopped by an | |
3112 | unconditional branch, try the insn at the branch target. We can | |
6f7775d5 JL |
3113 | redirect the branch if it works. |
3114 | ||
3115 | Don't do this if the insn at the branch target is a branch. */ | |
9c7e2978 RK |
3116 | if (slots_to_fill != slots_filled |
3117 | && trial | |
3118 | && GET_CODE (trial) == JUMP_INSN | |
3119 | && simplejump_p (trial) | |
3120 | && (target == 0 || JUMP_LABEL (trial) == target) | |
3121 | && (next_trial = next_active_insn (JUMP_LABEL (trial))) != 0 | |
3122 | && ! (GET_CODE (next_trial) == INSN | |
3123 | && GET_CODE (PATTERN (next_trial)) == SEQUENCE) | |
6f7775d5 | 3124 | && GET_CODE (next_trial) != JUMP_INSN |
9c7e2978 RK |
3125 | && ! insn_references_resource_p (next_trial, &set, 1) |
3126 | && ! insn_sets_resource_p (next_trial, &set, 1) | |
3127 | && ! insn_sets_resource_p (next_trial, &needed, 1) | |
3128 | #ifdef HAVE_cc0 | |
d6749dec | 3129 | && ! reg_mentioned_p (cc0_rtx, PATTERN (next_trial)) |
9c7e2978 RK |
3130 | #endif |
3131 | && ! (maybe_never && may_trap_p (PATTERN (next_trial))) | |
3132 | && (next_trial = try_split (PATTERN (next_trial), next_trial, 0)) | |
35523fce | 3133 | && eligible_for_delay (insn, slots_filled, next_trial, flags)) |
9c7e2978 RK |
3134 | { |
3135 | rtx new_label = next_active_insn (next_trial); | |
3136 | ||
3137 | if (new_label != 0) | |
3138 | new_label = get_label_before (new_label); | |
99f14de7 JW |
3139 | else |
3140 | new_label = find_end_label (); | |
9c7e2978 RK |
3141 | |
3142 | delay_list | |
3143 | = add_to_delay_list (copy_rtx (next_trial), delay_list); | |
3144 | slots_filled++; | |
326f06f7 | 3145 | reorg_redirect_jump (trial, new_label); |
9c7e2978 RK |
3146 | |
3147 | /* If we merged because we both jumped to the same place, | |
3148 | redirect the original insn also. */ | |
3149 | if (target) | |
326f06f7 | 3150 | reorg_redirect_jump (insn, new_label); |
9c7e2978 RK |
3151 | } |
3152 | } | |
3153 | ||
3154 | if (delay_list) | |
3155 | unfilled_slots_base[i] | |
3156 | = emit_delay_sequence (insn, delay_list, | |
3157 | slots_filled, slots_to_fill); | |
3158 | ||
3159 | if (slots_to_fill == slots_filled) | |
3160 | unfilled_slots_base[i] = 0; | |
3161 | ||
3162 | note_delay_statistics (slots_filled, 0); | |
3163 | } | |
3164 | ||
3165 | #ifdef DELAY_SLOTS_FOR_EPILOGUE | |
3166 | /* See if the epilogue needs any delay slots. Try to fill them if so. | |
3167 | The only thing we can do is scan backwards from the end of the | |
3168 | function. If we did this in a previous pass, it is incorrect to do it | |
3169 | again. */ | |
3170 | if (current_function_epilogue_delay_list) | |
3171 | return; | |
3172 | ||
3173 | slots_to_fill = DELAY_SLOTS_FOR_EPILOGUE; | |
3174 | if (slots_to_fill == 0) | |
3175 | return; | |
3176 | ||
3177 | slots_filled = 0; | |
9c7e2978 RK |
3178 | CLEAR_RESOURCE (&set); |
3179 | ||
8c2977e2 JW |
3180 | /* The frame pointer and stack pointer are needed at the beginning of |
3181 | the epilogue, so instructions setting them can not be put in the | |
3182 | epilogue delay slot. However, everything else needed at function | |
3183 | end is safe, so we don't want to use end_of_function_needs here. */ | |
3184 | CLEAR_RESOURCE (&needed); | |
3185 | if (frame_pointer_needed) | |
3186 | { | |
3187 | SET_HARD_REG_BIT (needed.regs, FRAME_POINTER_REGNUM); | |
3188 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
3189 | SET_HARD_REG_BIT (needed.regs, HARD_FRAME_POINTER_REGNUM); | |
3190 | #endif | |
3191 | #ifdef EXIT_IGNORE_STACK | |
3192 | if (! EXIT_IGNORE_STACK) | |
3193 | #endif | |
3194 | SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM); | |
3195 | } | |
3196 | else | |
3197 | SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM); | |
3198 | ||
9c7e2978 RK |
3199 | for (trial = get_last_insn (); ! stop_search_p (trial, 1); |
3200 | trial = PREV_INSN (trial)) | |
3201 | { | |
3202 | if (GET_CODE (trial) == NOTE) | |
3203 | continue; | |
3204 | pat = PATTERN (trial); | |
3205 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
3206 | continue; | |
3207 | ||
3208 | if (! insn_references_resource_p (trial, &set, 1) | |
3209 | && ! insn_sets_resource_p (trial, &needed, 1) | |
8c2977e2 | 3210 | && ! insn_sets_resource_p (trial, &set, 1) |
9c7e2978 RK |
3211 | #ifdef HAVE_cc0 |
3212 | /* Don't want to mess with cc0 here. */ | |
3213 | && ! reg_mentioned_p (cc0_rtx, pat) | |
3214 | #endif | |
3215 | ) | |
3216 | { | |
3217 | trial = try_split (pat, trial, 1); | |
3218 | if (ELIGIBLE_FOR_EPILOGUE_DELAY (trial, slots_filled)) | |
3219 | { | |
17448690 RK |
3220 | /* Here as well we are searching backward, so put the |
3221 | insns we find on the head of the list. */ | |
3222 | ||
9c7e2978 | 3223 | current_function_epilogue_delay_list |
17448690 RK |
3224 | = gen_rtx (INSN_LIST, VOIDmode, trial, |
3225 | current_function_epilogue_delay_list); | |
9c7e2978 RK |
3226 | mark_referenced_resources (trial, &end_of_function_needs, 1); |
3227 | update_block (trial, trial); | |
3228 | delete_insn (trial); | |
3229 | ||
3230 | /* Clear deleted bit so final.c will output the insn. */ | |
3231 | INSN_DELETED_P (trial) = 0; | |
3232 | ||
3233 | if (slots_to_fill == ++slots_filled) | |
3234 | break; | |
3235 | continue; | |
3236 | } | |
3237 | } | |
3238 | ||
26d970a5 | 3239 | mark_set_resources (trial, &set, 0, 1); |
9c7e2978 RK |
3240 | mark_referenced_resources (trial, &needed, 1); |
3241 | } | |
3242 | ||
3243 | note_delay_statistics (slots_filled, 0); | |
3244 | #endif | |
3245 | } | |
3246 | \f | |
3247 | /* Try to find insns to place in delay slots. | |
3248 | ||
3249 | INSN is the jump needing SLOTS_TO_FILL delay slots. It tests CONDITION | |
3250 | or is an unconditional branch if CONDITION is const_true_rtx. | |
3251 | *PSLOTS_FILLED is updated with the number of slots that we have filled. | |
3252 | ||
3253 | THREAD is a flow-of-control, either the insns to be executed if the | |
3254 | branch is true or if the branch is false, THREAD_IF_TRUE says which. | |
3255 | ||
3256 | OPPOSITE_THREAD is the thread in the opposite direction. It is used | |
3257 | to see if any potential delay slot insns set things needed there. | |
3258 | ||
3259 | LIKELY is non-zero if it is extremely likely that the branch will be | |
3260 | taken and THREAD_IF_TRUE is set. This is used for the branch at the | |
3261 | end of a loop back up to the top. | |
3262 | ||
3263 | OWN_THREAD and OWN_OPPOSITE_THREAD are true if we are the only user of the | |
3264 | thread. I.e., it is the fallthrough code of our jump or the target of the | |
3265 | jump when we are the only jump going there. | |
3266 | ||
3267 | If OWN_THREAD is false, it must be the "true" thread of a jump. In that | |
3268 | case, we can only take insns from the head of the thread for our delay | |
3269 | slot. We then adjust the jump to point after the insns we have taken. */ | |
3270 | ||
3271 | static rtx | |
3272 | fill_slots_from_thread (insn, condition, thread, opposite_thread, likely, | |
3273 | thread_if_true, own_thread, own_opposite_thread, | |
3274 | slots_to_fill, pslots_filled) | |
3275 | rtx insn; | |
3276 | rtx condition; | |
3277 | rtx thread, opposite_thread; | |
3278 | int likely; | |
3279 | int thread_if_true; | |
3280 | int own_thread, own_opposite_thread; | |
3281 | int slots_to_fill, *pslots_filled; | |
3282 | { | |
d674b9e3 | 3283 | rtx new_thread; |
9c7e2978 RK |
3284 | rtx delay_list = 0; |
3285 | struct resources opposite_needed, set, needed; | |
3286 | rtx trial; | |
3287 | int lose = 0; | |
3288 | int must_annul = 0; | |
35523fce | 3289 | int flags; |
9c7e2978 RK |
3290 | |
3291 | /* Validate our arguments. */ | |
3292 | if ((condition == const_true_rtx && ! thread_if_true) | |
3293 | || (! own_thread && ! thread_if_true)) | |
3294 | abort (); | |
3295 | ||
35523fce JL |
3296 | flags = get_jump_flags (insn, JUMP_LABEL (insn)); |
3297 | ||
9c7e2978 RK |
3298 | /* If our thread is the end of subroutine, we can't get any delay |
3299 | insns from that. */ | |
3300 | if (thread == 0) | |
3301 | return 0; | |
3302 | ||
3303 | /* If this is an unconditional branch, nothing is needed at the | |
3304 | opposite thread. Otherwise, compute what is needed there. */ | |
3305 | if (condition == const_true_rtx) | |
3306 | CLEAR_RESOURCE (&opposite_needed); | |
3307 | else | |
3308 | mark_target_live_regs (opposite_thread, &opposite_needed); | |
3309 | ||
d674b9e3 RK |
3310 | /* If the insn at THREAD can be split, do it here to avoid having to |
3311 | update THREAD and NEW_THREAD if it is done in the loop below. Also | |
3312 | initialize NEW_THREAD. */ | |
3313 | ||
d45cf215 | 3314 | new_thread = thread = try_split (PATTERN (thread), thread, 0); |
d674b9e3 | 3315 | |
9c7e2978 RK |
3316 | /* Scan insns at THREAD. We are looking for an insn that can be removed |
3317 | from THREAD (it neither sets nor references resources that were set | |
3318 | ahead of it and it doesn't set anything needs by the insns ahead of | |
3319 | it) and that either can be placed in an annulling insn or aren't | |
3320 | needed at OPPOSITE_THREAD. */ | |
3321 | ||
3322 | CLEAR_RESOURCE (&needed); | |
3323 | CLEAR_RESOURCE (&set); | |
3324 | ||
3325 | /* If we do not own this thread, we must stop as soon as we find | |
3326 | something that we can't put in a delay slot, since all we can do | |
3327 | is branch into THREAD at a later point. Therefore, labels stop | |
3328 | the search if this is not the `true' thread. */ | |
3329 | ||
3330 | for (trial = thread; | |
3331 | ! stop_search_p (trial, ! thread_if_true) && (! lose || own_thread); | |
3332 | trial = next_nonnote_insn (trial)) | |
3333 | { | |
70011923 | 3334 | rtx pat, old_trial; |
9c7e2978 RK |
3335 | |
3336 | /* If we have passed a label, we no longer own this thread. */ | |
3337 | if (GET_CODE (trial) == CODE_LABEL) | |
3338 | { | |
3339 | own_thread = 0; | |
3340 | continue; | |
3341 | } | |
3342 | ||
3343 | pat = PATTERN (trial); | |
3344 | if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER) | |
3345 | continue; | |
3346 | ||
3347 | /* If TRIAL conflicts with the insns ahead of it, we lose. Also, | |
3348 | don't separate or copy insns that set and use CC0. */ | |
3349 | if (! insn_references_resource_p (trial, &set, 1) | |
3350 | && ! insn_sets_resource_p (trial, &set, 1) | |
3351 | && ! insn_sets_resource_p (trial, &needed, 1) | |
3352 | #ifdef HAVE_cc0 | |
3353 | && ! (reg_mentioned_p (cc0_rtx, pat) | |
3354 | && (! own_thread || ! sets_cc0_p (pat))) | |
3355 | #endif | |
3356 | ) | |
3357 | { | |
5317d2f8 RK |
3358 | rtx prior_insn; |
3359 | ||
9c7e2978 RK |
3360 | /* If TRIAL is redundant with some insn before INSN, we don't |
3361 | actually need to add it to the delay list; we can merely pretend | |
3362 | we did. */ | |
f898abd7 | 3363 | if (prior_insn = redundant_insn (trial, insn, delay_list)) |
9c7e2978 RK |
3364 | { |
3365 | if (own_thread) | |
3366 | { | |
f1f9081a | 3367 | update_block (trial, thread); |
9bfe7965 | 3368 | if (trial == thread) |
8b11645c RK |
3369 | { |
3370 | thread = next_active_insn (thread); | |
3371 | if (new_thread == trial) | |
3372 | new_thread = thread; | |
3373 | } | |
9bfe7965 | 3374 | |
9c7e2978 RK |
3375 | delete_insn (trial); |
3376 | } | |
3377 | else | |
5317d2f8 RK |
3378 | { |
3379 | update_reg_unused_notes (prior_insn, trial); | |
088131ee | 3380 | new_thread = next_active_insn (trial); |
5317d2f8 | 3381 | } |
9c7e2978 RK |
3382 | |
3383 | continue; | |
3384 | } | |
3385 | ||
3386 | /* There are two ways we can win: If TRIAL doesn't set anything | |
3387 | needed at the opposite thread and can't trap, or if it can | |
3388 | go into an annulled delay slot. */ | |
3389 | if (condition == const_true_rtx | |
3390 | || (! insn_sets_resource_p (trial, &opposite_needed, 1) | |
3391 | && ! may_trap_p (pat))) | |
3392 | { | |
70011923 | 3393 | old_trial = trial; |
9c7e2978 | 3394 | trial = try_split (pat, trial, 0); |
70011923 ILT |
3395 | if (new_thread == old_trial) |
3396 | new_thread = trial; | |
9b9cd81b JW |
3397 | if (thread == old_trial) |
3398 | thread = trial; | |
9c7e2978 | 3399 | pat = PATTERN (trial); |
35523fce | 3400 | if (eligible_for_delay (insn, *pslots_filled, trial, flags)) |
9c7e2978 RK |
3401 | goto winner; |
3402 | } | |
3403 | else if (0 | |
3404 | #ifdef ANNUL_IFTRUE_SLOTS | |
3405 | || ! thread_if_true | |
3406 | #endif | |
3407 | #ifdef ANNUL_IFFALSE_SLOTS | |
3408 | || thread_if_true | |
3409 | #endif | |
3410 | ) | |
3411 | { | |
70011923 | 3412 | old_trial = trial; |
9c7e2978 | 3413 | trial = try_split (pat, trial, 0); |
70011923 ILT |
3414 | if (new_thread == old_trial) |
3415 | new_thread = trial; | |
9c7e2978 RK |
3416 | pat = PATTERN (trial); |
3417 | if ((thread_if_true | |
35523fce JL |
3418 | ? eligible_for_annul_false (insn, *pslots_filled, trial, flags) |
3419 | : eligible_for_annul_true (insn, *pslots_filled, trial, flags))) | |
9c7e2978 RK |
3420 | { |
3421 | rtx temp; | |
3422 | ||
3423 | must_annul = 1; | |
3424 | winner: | |
3425 | ||
3426 | #ifdef HAVE_cc0 | |
3427 | if (reg_mentioned_p (cc0_rtx, pat)) | |
3428 | link_cc0_insns (trial); | |
3429 | #endif | |
3430 | ||
3431 | /* If we own this thread, delete the insn. If this is the | |
3432 | destination of a branch, show that a basic block status | |
3433 | may have been updated. In any case, mark the new | |
3434 | starting point of this thread. */ | |
3435 | if (own_thread) | |
3436 | { | |
f1f9081a | 3437 | update_block (trial, thread); |
9c7e2978 RK |
3438 | delete_insn (trial); |
3439 | } | |
3440 | else | |
3441 | new_thread = next_active_insn (trial); | |
3442 | ||
3443 | temp = own_thread ? trial : copy_rtx (trial); | |
3444 | if (thread_if_true) | |
3445 | INSN_FROM_TARGET_P (temp) = 1; | |
3446 | ||
3447 | delay_list = add_to_delay_list (temp, delay_list); | |
3448 | ||
3449 | if (slots_to_fill == ++(*pslots_filled)) | |
3450 | { | |
3451 | /* Even though we have filled all the slots, we | |
3452 | may be branching to a location that has a | |
3453 | redundant insn. Skip any if so. */ | |
3454 | while (new_thread && ! own_thread | |
3455 | && ! insn_sets_resource_p (new_thread, &set, 1) | |
3456 | && ! insn_sets_resource_p (new_thread, &needed, 1) | |
3457 | && ! insn_references_resource_p (new_thread, | |
3458 | &set, 1) | |
f898abd7 | 3459 | && redundant_insn (new_thread, insn, delay_list)) |
9c7e2978 RK |
3460 | new_thread = next_active_insn (new_thread); |
3461 | break; | |
3462 | } | |
3463 | ||
3464 | continue; | |
3465 | } | |
3466 | } | |
3467 | } | |
3468 | ||
3469 | /* This insn can't go into a delay slot. */ | |
3470 | lose = 1; | |
26d970a5 | 3471 | mark_set_resources (trial, &set, 0, 1); |
9c7e2978 RK |
3472 | mark_referenced_resources (trial, &needed, 1); |
3473 | ||
3474 | /* Ensure we don't put insns between the setting of cc and the comparison | |
3475 | by moving a setting of cc into an earlier delay slot since these insns | |
3476 | could clobber the condition code. */ | |
3477 | set.cc = 1; | |
3478 | ||
3479 | /* If this insn is a register-register copy and the next insn has | |
3480 | a use of our destination, change it to use our source. That way, | |
3481 | it will become a candidate for our delay slot the next time | |
3482 | through this loop. This case occurs commonly in loops that | |
3483 | scan a list. | |
3484 | ||
3485 | We could check for more complex cases than those tested below, | |
3486 | but it doesn't seem worth it. It might also be a good idea to try | |
9b72fab4 RK |
3487 | to swap the two insns. That might do better. |
3488 | ||
963d6142 RK |
3489 | We can't do this if the next insn modifies our destination, because |
3490 | that would make the replacement into the insn invalid. We also can't | |
3491 | do this if it modifies our source, because it might be an earlyclobber | |
3492 | operand. This latter test also prevents updating the contents of | |
3493 | a PRE_INC. */ | |
9c7e2978 RK |
3494 | |
3495 | if (GET_CODE (trial) == INSN && GET_CODE (pat) == SET | |
3496 | && GET_CODE (SET_SRC (pat)) == REG | |
3497 | && GET_CODE (SET_DEST (pat)) == REG) | |
3498 | { | |
3499 | rtx next = next_nonnote_insn (trial); | |
9c7e2978 RK |
3500 | |
3501 | if (next && GET_CODE (next) == INSN | |
9b72fab4 RK |
3502 | && GET_CODE (PATTERN (next)) != USE |
3503 | && ! reg_set_p (SET_DEST (pat), next) | |
963d6142 | 3504 | && ! reg_set_p (SET_SRC (pat), next) |
9b72fab4 | 3505 | && reg_referenced_p (SET_DEST (pat), PATTERN (next))) |
9c7e2978 RK |
3506 | validate_replace_rtx (SET_DEST (pat), SET_SRC (pat), next); |
3507 | } | |
3508 | } | |
3509 | ||
3510 | /* If we stopped on a branch insn that has delay slots, see if we can | |
3511 | steal some of the insns in those slots. */ | |
3512 | if (trial && GET_CODE (trial) == INSN | |
3513 | && GET_CODE (PATTERN (trial)) == SEQUENCE | |
3514 | && GET_CODE (XVECEXP (PATTERN (trial), 0, 0)) == JUMP_INSN) | |
3515 | { | |
3516 | /* If this is the `true' thread, we will want to follow the jump, | |
3517 | so we can only do this if we have taken everything up to here. */ | |
3518 | if (thread_if_true && trial == new_thread) | |
3519 | delay_list | |
3520 | = steal_delay_list_from_target (insn, condition, PATTERN (trial), | |
3521 | delay_list, &set, &needed, | |
3522 | &opposite_needed, slots_to_fill, | |
3523 | pslots_filled, &must_annul, | |
3524 | &new_thread); | |
3525 | else if (! thread_if_true) | |
3526 | delay_list | |
3527 | = steal_delay_list_from_fallthrough (insn, condition, | |
3528 | PATTERN (trial), | |
3529 | delay_list, &set, &needed, | |
3530 | &opposite_needed, slots_to_fill, | |
3531 | pslots_filled, &must_annul); | |
3532 | } | |
3533 | ||
3534 | /* If we haven't found anything for this delay slot and it is very | |
3535 | likely that the branch will be taken, see if the insn at our target | |
d674b9e3 RK |
3536 | increments or decrements a register with an increment that does not |
3537 | depend on the destination register. If so, try to place the opposite | |
9c7e2978 RK |
3538 | arithmetic insn after the jump insn and put the arithmetic insn in the |
3539 | delay slot. If we can't do this, return. */ | |
3540 | if (delay_list == 0 && likely && new_thread && GET_CODE (new_thread) == INSN) | |
3541 | { | |
3542 | rtx pat = PATTERN (new_thread); | |
3543 | rtx dest; | |
3544 | rtx src; | |
3545 | ||
d674b9e3 | 3546 | trial = new_thread; |
9c7e2978 RK |
3547 | pat = PATTERN (trial); |
3548 | ||
3549 | if (GET_CODE (trial) != INSN || GET_CODE (pat) != SET | |
35523fce | 3550 | || ! eligible_for_delay (insn, 0, trial, flags)) |
9c7e2978 RK |
3551 | return 0; |
3552 | ||
3553 | dest = SET_DEST (pat), src = SET_SRC (pat); | |
3554 | if ((GET_CODE (src) == PLUS || GET_CODE (src) == MINUS) | |
d674b9e3 RK |
3555 | && rtx_equal_p (XEXP (src, 0), dest) |
3556 | && ! reg_overlap_mentioned_p (dest, XEXP (src, 1))) | |
9c7e2978 RK |
3557 | { |
3558 | rtx other = XEXP (src, 1); | |
3559 | rtx new_arith; | |
3560 | rtx ninsn; | |
3561 | ||
3562 | /* If this is a constant adjustment, use the same code with | |
3563 | the negated constant. Otherwise, reverse the sense of the | |
3564 | arithmetic. */ | |
3565 | if (GET_CODE (other) == CONST_INT) | |
3566 | new_arith = gen_rtx (GET_CODE (src), GET_MODE (src), dest, | |
3567 | negate_rtx (GET_MODE (src), other)); | |
3568 | else | |
3569 | new_arith = gen_rtx (GET_CODE (src) == PLUS ? MINUS : PLUS, | |
3570 | GET_MODE (src), dest, other); | |
3571 | ||
3572 | ninsn = emit_insn_after (gen_rtx (SET, VOIDmode, dest, new_arith), | |
3573 | insn); | |
3574 | ||
3575 | if (recog_memoized (ninsn) < 0 | |
3576 | || (insn_extract (ninsn), | |
3577 | ! constrain_operands (INSN_CODE (ninsn), 1))) | |
3578 | { | |
3579 | delete_insn (ninsn); | |
3580 | return 0; | |
3581 | } | |
3582 | ||
3583 | if (own_thread) | |
3584 | { | |
f1f9081a | 3585 | update_block (trial, thread); |
9c7e2978 RK |
3586 | delete_insn (trial); |
3587 | } | |
3588 | else | |
3589 | new_thread = next_active_insn (trial); | |
3590 | ||
3591 | ninsn = own_thread ? trial : copy_rtx (trial); | |
3592 | if (thread_if_true) | |
3593 | INSN_FROM_TARGET_P (ninsn) = 1; | |
3594 | ||
fb3821f7 | 3595 | delay_list = add_to_delay_list (ninsn, NULL_RTX); |
9c7e2978 RK |
3596 | (*pslots_filled)++; |
3597 | } | |
3598 | } | |
3599 | ||
3600 | if (delay_list && must_annul) | |
3601 | INSN_ANNULLED_BRANCH_P (insn) = 1; | |
3602 | ||
3603 | /* If we are to branch into the middle of this thread, find an appropriate | |
3604 | label or make a new one if none, and redirect INSN to it. If we hit the | |
3605 | end of the function, use the end-of-function label. */ | |
3606 | if (new_thread != thread) | |
3607 | { | |
3608 | rtx label; | |
3609 | ||
3610 | if (! thread_if_true) | |
3611 | abort (); | |
3612 | ||
3613 | if (new_thread && GET_CODE (new_thread) == JUMP_INSN | |
3614 | && (simplejump_p (new_thread) | |
b304ad47 JL |
3615 | || GET_CODE (PATTERN (new_thread)) == RETURN) |
3616 | && redirect_with_delay_list_safe_p (insn, | |
3617 | JUMP_LABEL (new_thread), | |
3618 | delay_list)) | |
22422dbf | 3619 | new_thread = follow_jumps (JUMP_LABEL (new_thread)); |
9c7e2978 RK |
3620 | |
3621 | if (new_thread == 0) | |
3622 | label = find_end_label (); | |
3623 | else if (GET_CODE (new_thread) == CODE_LABEL) | |
3624 | label = new_thread; | |
3625 | else | |
3626 | label = get_label_before (new_thread); | |
3627 | ||
326f06f7 | 3628 | reorg_redirect_jump (insn, label); |
9c7e2978 RK |
3629 | } |
3630 | ||
3631 | return delay_list; | |
3632 | } | |
3633 | \f | |
3634 | /* Make another attempt to find insns to place in delay slots. | |
3635 | ||
3636 | We previously looked for insns located in front of the delay insn | |
3637 | and, for non-jump delay insns, located behind the delay insn. | |
3638 | ||
3639 | Here only try to schedule jump insns and try to move insns from either | |
3640 | the target or the following insns into the delay slot. If annulling is | |
3641 | supported, we will be likely to do this. Otherwise, we can do this only | |
3642 | if safe. */ | |
3643 | ||
3644 | static void | |
3645 | fill_eager_delay_slots (first) | |
3646 | rtx first; | |
3647 | { | |
3648 | register rtx insn; | |
3649 | register int i; | |
3650 | int num_unfilled_slots = unfilled_slots_next - unfilled_slots_base; | |
3651 | ||
3652 | for (i = 0; i < num_unfilled_slots; i++) | |
3653 | { | |
3654 | rtx condition; | |
3655 | rtx target_label, insn_at_target, fallthrough_insn; | |
3656 | rtx delay_list = 0; | |
3657 | int own_target; | |
3658 | int own_fallthrough; | |
3659 | int prediction, slots_to_fill, slots_filled; | |
3660 | ||
3661 | insn = unfilled_slots_base[i]; | |
3662 | if (insn == 0 | |
3663 | || INSN_DELETED_P (insn) | |
3664 | || GET_CODE (insn) != JUMP_INSN | |
3480bb98 | 3665 | || ! (condjump_p (insn) || condjump_in_parallel_p (insn))) |
9c7e2978 RK |
3666 | continue; |
3667 | ||
3668 | slots_to_fill = num_delay_slots (insn); | |
3669 | if (slots_to_fill == 0) | |
3670 | abort (); | |
3671 | ||
3672 | slots_filled = 0; | |
3673 | target_label = JUMP_LABEL (insn); | |
3674 | condition = get_branch_condition (insn, target_label); | |
3675 | ||
3676 | if (condition == 0) | |
3677 | continue; | |
3678 | ||
3679 | /* Get the next active fallthough and target insns and see if we own | |
3680 | them. Then see whether the branch is likely true. We don't need | |
3681 | to do a lot of this for unconditional branches. */ | |
3682 | ||
3683 | insn_at_target = next_active_insn (target_label); | |
3684 | own_target = own_thread_p (target_label, target_label, 0); | |
3685 | ||
3686 | if (condition == const_true_rtx) | |
3687 | { | |
3688 | own_fallthrough = 0; | |
3689 | fallthrough_insn = 0; | |
3690 | prediction = 2; | |
3691 | } | |
3692 | else | |
3693 | { | |
3694 | fallthrough_insn = next_active_insn (insn); | |
fb3821f7 | 3695 | own_fallthrough = own_thread_p (NEXT_INSN (insn), NULL_RTX, 1); |
9c7e2978 RK |
3696 | prediction = mostly_true_jump (insn, condition); |
3697 | } | |
3698 | ||
3699 | /* If this insn is expected to branch, first try to get insns from our | |
3700 | target, then our fallthrough insns. If it is not, expected to branch, | |
3701 | try the other order. */ | |
3702 | ||
0275a51b | 3703 | if (prediction > 0) |
9c7e2978 RK |
3704 | { |
3705 | delay_list | |
3706 | = fill_slots_from_thread (insn, condition, insn_at_target, | |
3707 | fallthrough_insn, prediction == 2, 1, | |
3708 | own_target, own_fallthrough, | |
3709 | slots_to_fill, &slots_filled); | |
3710 | ||
3711 | if (delay_list == 0 && own_fallthrough) | |
3712 | { | |
3713 | /* Even though we didn't find anything for delay slots, | |
3714 | we might have found a redundant insn which we deleted | |
3715 | from the thread that was filled. So we have to recompute | |
3716 | the next insn at the target. */ | |
3717 | target_label = JUMP_LABEL (insn); | |
3718 | insn_at_target = next_active_insn (target_label); | |
3719 | ||
3720 | delay_list | |
3721 | = fill_slots_from_thread (insn, condition, fallthrough_insn, | |
3722 | insn_at_target, 0, 0, | |
3723 | own_fallthrough, own_target, | |
3724 | slots_to_fill, &slots_filled); | |
3725 | } | |
3726 | } | |
3727 | else | |
3728 | { | |
3729 | if (own_fallthrough) | |
3730 | delay_list | |
3731 | = fill_slots_from_thread (insn, condition, fallthrough_insn, | |
3732 | insn_at_target, 0, 0, | |
3733 | own_fallthrough, own_target, | |
3734 | slots_to_fill, &slots_filled); | |
3735 | ||
3736 | if (delay_list == 0) | |
3737 | delay_list | |
3738 | = fill_slots_from_thread (insn, condition, insn_at_target, | |
3739 | next_active_insn (insn), 0, 1, | |
3740 | own_target, own_fallthrough, | |
3741 | slots_to_fill, &slots_filled); | |
3742 | } | |
3743 | ||
3744 | if (delay_list) | |
3745 | unfilled_slots_base[i] | |
3746 | = emit_delay_sequence (insn, delay_list, | |
3747 | slots_filled, slots_to_fill); | |
3748 | ||
3749 | if (slots_to_fill == slots_filled) | |
3750 | unfilled_slots_base[i] = 0; | |
3751 | ||
3752 | note_delay_statistics (slots_filled, 1); | |
3753 | } | |
3754 | } | |
3755 | \f | |
3756 | /* Once we have tried two ways to fill a delay slot, make a pass over the | |
3757 | code to try to improve the results and to do such things as more jump | |
3758 | threading. */ | |
3759 | ||
3760 | static void | |
3761 | relax_delay_slots (first) | |
3762 | rtx first; | |
3763 | { | |
3764 | register rtx insn, next, pat; | |
3765 | register rtx trial, delay_insn, target_label; | |
3766 | ||
3767 | /* Look at every JUMP_INSN and see if we can improve it. */ | |
3768 | for (insn = first; insn; insn = next) | |
3769 | { | |
3770 | rtx other; | |
3771 | ||
3772 | next = next_active_insn (insn); | |
3773 | ||
3774 | /* If this is a jump insn, see if it now jumps to a jump, jumps to | |
3775 | the next insn, or jumps to a label that is not the last of a | |
3776 | group of consecutive labels. */ | |
3777 | if (GET_CODE (insn) == JUMP_INSN | |
3480bb98 | 3778 | && (condjump_p (insn) || condjump_in_parallel_p (insn)) |
9c7e2978 RK |
3779 | && (target_label = JUMP_LABEL (insn)) != 0) |
3780 | { | |
22422dbf | 3781 | target_label = follow_jumps (target_label); |
9c7e2978 RK |
3782 | target_label = prev_label (next_active_insn (target_label)); |
3783 | ||
de5292c7 RK |
3784 | if (target_label == 0) |
3785 | target_label = find_end_label (); | |
3786 | ||
3480bb98 JL |
3787 | if (next_active_insn (target_label) == next |
3788 | && ! condjump_in_parallel_p (insn)) | |
9c7e2978 RK |
3789 | { |
3790 | delete_jump (insn); | |
3791 | continue; | |
3792 | } | |
3793 | ||
3794 | if (target_label != JUMP_LABEL (insn)) | |
326f06f7 | 3795 | reorg_redirect_jump (insn, target_label); |
9c7e2978 RK |
3796 | |
3797 | /* See if this jump branches around a unconditional jump. | |
3798 | If so, invert this jump and point it to the target of the | |
3799 | second jump. */ | |
3800 | if (next && GET_CODE (next) == JUMP_INSN | |
3801 | && (simplejump_p (next) || GET_CODE (PATTERN (next)) == RETURN) | |
3802 | && next_active_insn (target_label) == next_active_insn (next) | |
3803 | && no_labels_between_p (insn, next)) | |
3804 | { | |
3805 | rtx label = JUMP_LABEL (next); | |
3806 | ||
3807 | /* Be careful how we do this to avoid deleting code or | |
3808 | labels that are momentarily dead. See similar optimization | |
3809 | in jump.c. | |
3810 | ||
3811 | We also need to ensure we properly handle the case when | |
3812 | invert_jump fails. */ | |
3813 | ||
3814 | ++LABEL_NUSES (target_label); | |
3815 | if (label) | |
3816 | ++LABEL_NUSES (label); | |
3817 | ||
3818 | if (invert_jump (insn, label)) | |
3819 | { | |
3820 | delete_insn (next); | |
3821 | next = insn; | |
3822 | } | |
3823 | ||
3824 | if (label) | |
3825 | --LABEL_NUSES (label); | |
3826 | ||
3827 | if (--LABEL_NUSES (target_label) == 0) | |
3828 | delete_insn (target_label); | |
3829 | ||
3830 | continue; | |
3831 | } | |
3832 | } | |
3833 | ||
3834 | /* If this is an unconditional jump and the previous insn is a | |
3835 | conditional jump, try reversing the condition of the previous | |
3836 | insn and swapping our targets. The next pass might be able to | |
3837 | fill the slots. | |
3838 | ||
3839 | Don't do this if we expect the conditional branch to be true, because | |
3840 | we would then be making the more common case longer. */ | |
3841 | ||
3842 | if (GET_CODE (insn) == JUMP_INSN | |
3843 | && (simplejump_p (insn) || GET_CODE (PATTERN (insn)) == RETURN) | |
3844 | && (other = prev_active_insn (insn)) != 0 | |
3480bb98 | 3845 | && (condjump_p (other) || condjump_in_parallel_p (other)) |
9c7e2978 | 3846 | && no_labels_between_p (other, insn) |
0275a51b RK |
3847 | && 0 < mostly_true_jump (other, |
3848 | get_branch_condition (other, | |
3849 | JUMP_LABEL (other)))) | |
9c7e2978 RK |
3850 | { |
3851 | rtx other_target = JUMP_LABEL (other); | |
7ca4e06e | 3852 | target_label = JUMP_LABEL (insn); |
9c7e2978 RK |
3853 | |
3854 | /* Increment the count of OTHER_TARGET, so it doesn't get deleted | |
3855 | as we move the label. */ | |
3856 | if (other_target) | |
3857 | ++LABEL_NUSES (other_target); | |
3858 | ||
3859 | if (invert_jump (other, target_label)) | |
326f06f7 | 3860 | reorg_redirect_jump (insn, other_target); |
9c7e2978 RK |
3861 | |
3862 | if (other_target) | |
3863 | --LABEL_NUSES (other_target); | |
3864 | } | |
3865 | ||
3866 | /* Now look only at cases where we have filled a delay slot. */ | |
3867 | if (GET_CODE (insn) != INSN | |
3868 | || GET_CODE (PATTERN (insn)) != SEQUENCE) | |
3869 | continue; | |
3870 | ||
3871 | pat = PATTERN (insn); | |
3872 | delay_insn = XVECEXP (pat, 0, 0); | |
3873 | ||
3874 | /* See if the first insn in the delay slot is redundant with some | |
3875 | previous insn. Remove it from the delay slot if so; then set up | |
3876 | to reprocess this insn. */ | |
f898abd7 | 3877 | if (redundant_insn (XVECEXP (pat, 0, 1), delay_insn, 0)) |
9c7e2978 RK |
3878 | { |
3879 | delete_from_delay_slot (XVECEXP (pat, 0, 1)); | |
3880 | next = prev_active_insn (next); | |
3881 | continue; | |
3882 | } | |
3883 | ||
3884 | /* Now look only at the cases where we have a filled JUMP_INSN. */ | |
3885 | if (GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) != JUMP_INSN | |
3480bb98 JL |
3886 | || ! (condjump_p (XVECEXP (PATTERN (insn), 0, 0)) |
3887 | || condjump_in_parallel_p (XVECEXP (PATTERN (insn), 0, 0)))) | |
9c7e2978 RK |
3888 | continue; |
3889 | ||
3890 | target_label = JUMP_LABEL (delay_insn); | |
3891 | ||
3892 | if (target_label) | |
3893 | { | |
3894 | /* If this jump goes to another unconditional jump, thread it, but | |
3895 | don't convert a jump into a RETURN here. */ | |
22422dbf | 3896 | trial = follow_jumps (target_label); |
9e94dc88 JW |
3897 | /* We use next_real_insn instead of next_active_insn, so that |
3898 | the special USE insns emitted by reorg won't be ignored. | |
3899 | If they are ignored, then they will get deleted if target_label | |
3900 | is now unreachable, and that would cause mark_target_live_regs | |
3901 | to fail. */ | |
3902 | trial = prev_label (next_real_insn (trial)); | |
9c7e2978 RK |
3903 | if (trial == 0 && target_label != 0) |
3904 | trial = find_end_label (); | |
3905 | ||
83fd5651 JL |
3906 | if (trial != target_label |
3907 | && redirect_with_delay_slots_safe_p (delay_insn, trial, insn)) | |
9c7e2978 | 3908 | { |
326f06f7 | 3909 | reorg_redirect_jump (delay_insn, trial); |
9c7e2978 RK |
3910 | target_label = trial; |
3911 | } | |
3912 | ||
3913 | /* If the first insn at TARGET_LABEL is redundant with a previous | |
3914 | insn, redirect the jump to the following insn process again. */ | |
3915 | trial = next_active_insn (target_label); | |
3916 | if (trial && GET_CODE (PATTERN (trial)) != SEQUENCE | |
f898abd7 | 3917 | && redundant_insn (trial, insn, 0)) |
9c7e2978 RK |
3918 | { |
3919 | trial = next_active_insn (trial); | |
3920 | if (trial == 0) | |
3921 | target_label = find_end_label (); | |
3922 | else | |
3923 | target_label = get_label_before (trial); | |
326f06f7 | 3924 | reorg_redirect_jump (delay_insn, target_label); |
9c7e2978 RK |
3925 | next = insn; |
3926 | continue; | |
3927 | } | |
3928 | ||
3929 | /* Similarly, if it is an unconditional jump with one insn in its | |
3930 | delay list and that insn is redundant, thread the jump. */ | |
3931 | if (trial && GET_CODE (PATTERN (trial)) == SEQUENCE | |
3932 | && XVECLEN (PATTERN (trial), 0) == 2 | |
3933 | && GET_CODE (XVECEXP (PATTERN (trial), 0, 0)) == JUMP_INSN | |
3934 | && (simplejump_p (XVECEXP (PATTERN (trial), 0, 0)) | |
3935 | || GET_CODE (PATTERN (XVECEXP (PATTERN (trial), 0, 0))) == RETURN) | |
f898abd7 | 3936 | && redundant_insn (XVECEXP (PATTERN (trial), 0, 1), insn, 0)) |
9c7e2978 RK |
3937 | { |
3938 | target_label = JUMP_LABEL (XVECEXP (PATTERN (trial), 0, 0)); | |
3939 | if (target_label == 0) | |
3940 | target_label = find_end_label (); | |
83fd5651 JL |
3941 | |
3942 | if (redirect_with_delay_slots_safe_p (delay_insn, target_label, | |
3943 | insn)) | |
3944 | { | |
3945 | reorg_redirect_jump (delay_insn, target_label); | |
3946 | next = insn; | |
3947 | continue; | |
3948 | } | |
9c7e2978 RK |
3949 | } |
3950 | } | |
3951 | ||
3952 | if (! INSN_ANNULLED_BRANCH_P (delay_insn) | |
3953 | && prev_active_insn (target_label) == insn | |
3480bb98 | 3954 | && ! condjump_in_parallel_p (delay_insn) |
9c7e2978 RK |
3955 | #ifdef HAVE_cc0 |
3956 | /* If the last insn in the delay slot sets CC0 for some insn, | |
3957 | various code assumes that it is in a delay slot. We could | |
3958 | put it back where it belonged and delete the register notes, | |
6dc42e49 | 3959 | but it doesn't seem worthwhile in this uncommon case. */ |
9c7e2978 | 3960 | && ! find_reg_note (XVECEXP (pat, 0, XVECLEN (pat, 0) - 1), |
fb3821f7 | 3961 | REG_CC_USER, NULL_RTX) |
9c7e2978 RK |
3962 | #endif |
3963 | ) | |
3964 | { | |
ac224823 RK |
3965 | int i; |
3966 | ||
9c7e2978 RK |
3967 | /* All this insn does is execute its delay list and jump to the |
3968 | following insn. So delete the jump and just execute the delay | |
3969 | list insns. | |
3970 | ||
3971 | We do this by deleting the INSN containing the SEQUENCE, then | |
3972 | re-emitting the insns separately, and then deleting the jump. | |
3973 | This allows the count of the jump target to be properly | |
3974 | decremented. */ | |
3975 | ||
ac224823 RK |
3976 | /* Clear the from target bit, since these insns are no longer |
3977 | in delay slots. */ | |
3978 | for (i = 0; i < XVECLEN (pat, 0); i++) | |
3979 | INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)) = 0; | |
3980 | ||
9c7e2978 RK |
3981 | trial = PREV_INSN (insn); |
3982 | delete_insn (insn); | |
3983 | emit_insn_after (pat, trial); | |
3984 | delete_scheduled_jump (delay_insn); | |
3985 | continue; | |
3986 | } | |
3987 | ||
51ec2375 JW |
3988 | /* See if this is an unconditional jump around a single insn which is |
3989 | identical to the one in its delay slot. In this case, we can just | |
3990 | delete the branch and the insn in its delay slot. */ | |
3991 | if (next && GET_CODE (next) == INSN | |
3992 | && prev_label (next_active_insn (next)) == target_label | |
3993 | && simplejump_p (insn) | |
3994 | && XVECLEN (pat, 0) == 2 | |
3995 | && rtx_equal_p (PATTERN (next), PATTERN (XVECEXP (pat, 0, 1)))) | |
3996 | { | |
3997 | delete_insn (insn); | |
3998 | continue; | |
3999 | } | |
4000 | ||
9c7e2978 RK |
4001 | /* See if this jump (with its delay slots) branches around another |
4002 | jump (without delay slots). If so, invert this jump and point | |
4003 | it to the target of the second jump. We cannot do this for | |
4004 | annulled jumps, though. Again, don't convert a jump to a RETURN | |
4005 | here. */ | |
4006 | if (! INSN_ANNULLED_BRANCH_P (delay_insn) | |
4007 | && next && GET_CODE (next) == JUMP_INSN | |
4008 | && (simplejump_p (next) || GET_CODE (PATTERN (next)) == RETURN) | |
4009 | && next_active_insn (target_label) == next_active_insn (next) | |
4010 | && no_labels_between_p (insn, next)) | |
4011 | { | |
4012 | rtx label = JUMP_LABEL (next); | |
4013 | rtx old_label = JUMP_LABEL (delay_insn); | |
4014 | ||
4015 | if (label == 0) | |
4016 | label = find_end_label (); | |
4017 | ||
83fd5651 | 4018 | if (redirect_with_delay_slots_safe_p (delay_insn, label, insn)) |
9c7e2978 | 4019 | { |
83fd5651 JL |
4020 | /* Be careful how we do this to avoid deleting code or labels |
4021 | that are momentarily dead. See similar optimization in | |
4022 | jump.c */ | |
4023 | if (old_label) | |
4024 | ++LABEL_NUSES (old_label); | |
9c7e2978 | 4025 | |
83fd5651 JL |
4026 | if (invert_jump (delay_insn, label)) |
4027 | { | |
9e8b2461 RK |
4028 | int i; |
4029 | ||
4030 | /* Must update the INSN_FROM_TARGET_P bits now that | |
4031 | the branch is reversed, so that mark_target_live_regs | |
4032 | will handle the delay slot insn correctly. */ | |
4033 | for (i = 1; i < XVECLEN (PATTERN (insn), 0); i++) | |
4034 | { | |
4035 | rtx slot = XVECEXP (PATTERN (insn), 0, i); | |
4036 | INSN_FROM_TARGET_P (slot) = ! INSN_FROM_TARGET_P (slot); | |
4037 | } | |
4038 | ||
83fd5651 JL |
4039 | delete_insn (next); |
4040 | next = insn; | |
4041 | } | |
4042 | ||
4043 | if (old_label && --LABEL_NUSES (old_label) == 0) | |
4044 | delete_insn (old_label); | |
4045 | continue; | |
4046 | } | |
9c7e2978 RK |
4047 | } |
4048 | ||
4049 | /* If we own the thread opposite the way this insn branches, see if we | |
4050 | can merge its delay slots with following insns. */ | |
4051 | if (INSN_FROM_TARGET_P (XVECEXP (pat, 0, 1)) | |
4052 | && own_thread_p (NEXT_INSN (insn), 0, 1)) | |
4053 | try_merge_delay_insns (insn, next); | |
4054 | else if (! INSN_FROM_TARGET_P (XVECEXP (pat, 0, 1)) | |
4055 | && own_thread_p (target_label, target_label, 0)) | |
4056 | try_merge_delay_insns (insn, next_active_insn (target_label)); | |
4057 | ||
4058 | /* If we get here, we haven't deleted INSN. But we may have deleted | |
4059 | NEXT, so recompute it. */ | |
4060 | next = next_active_insn (insn); | |
4061 | } | |
4062 | } | |
4063 | \f | |
4064 | #ifdef HAVE_return | |
4065 | ||
4066 | /* Look for filled jumps to the end of function label. We can try to convert | |
4067 | them into RETURN insns if the insns in the delay slot are valid for the | |
4068 | RETURN as well. */ | |
4069 | ||
4070 | static void | |
4071 | make_return_insns (first) | |
4072 | rtx first; | |
4073 | { | |
4074 | rtx insn, jump_insn, pat; | |
4075 | rtx real_return_label = end_of_function_label; | |
4076 | int slots, i; | |
4077 | ||
4078 | /* See if there is a RETURN insn in the function other than the one we | |
4079 | made for END_OF_FUNCTION_LABEL. If so, set up anything we can't change | |
4080 | into a RETURN to jump to it. */ | |
4081 | for (insn = first; insn; insn = NEXT_INSN (insn)) | |
4082 | if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == RETURN) | |
4083 | { | |
4084 | real_return_label = get_label_before (insn); | |
4085 | break; | |
4086 | } | |
4087 | ||
4088 | /* Show an extra usage of REAL_RETURN_LABEL so it won't go away if it | |
4089 | was equal to END_OF_FUNCTION_LABEL. */ | |
4090 | LABEL_NUSES (real_return_label)++; | |
4091 | ||
4092 | /* Clear the list of insns to fill so we can use it. */ | |
4093 | obstack_free (&unfilled_slots_obstack, unfilled_firstobj); | |
4094 | ||
4095 | for (insn = first; insn; insn = NEXT_INSN (insn)) | |
4096 | { | |
35523fce JL |
4097 | int flags; |
4098 | ||
9c7e2978 RK |
4099 | /* Only look at filled JUMP_INSNs that go to the end of function |
4100 | label. */ | |
4101 | if (GET_CODE (insn) != INSN | |
4102 | || GET_CODE (PATTERN (insn)) != SEQUENCE | |
4103 | || GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) != JUMP_INSN | |
4104 | || JUMP_LABEL (XVECEXP (PATTERN (insn), 0, 0)) != end_of_function_label) | |
4105 | continue; | |
4106 | ||
4107 | pat = PATTERN (insn); | |
4108 | jump_insn = XVECEXP (pat, 0, 0); | |
4109 | ||
18beb3e9 | 4110 | /* If we can't make the jump into a RETURN, try to redirect it to the best |
9c7e2978 | 4111 | RETURN and go on to the next insn. */ |
326f06f7 | 4112 | if (! reorg_redirect_jump (jump_insn, NULL_RTX)) |
9c7e2978 | 4113 | { |
18beb3e9 JL |
4114 | /* Make sure redirecting the jump will not invalidate the delay |
4115 | slot insns. */ | |
4116 | if (redirect_with_delay_slots_safe_p (jump_insn, | |
4117 | real_return_label, | |
4118 | insn)) | |
4119 | reorg_redirect_jump (jump_insn, real_return_label); | |
9c7e2978 RK |
4120 | continue; |
4121 | } | |
4122 | ||
4123 | /* See if this RETURN can accept the insns current in its delay slot. | |
4124 | It can if it has more or an equal number of slots and the contents | |
4125 | of each is valid. */ | |
4126 | ||
35523fce | 4127 | flags = get_jump_flags (jump_insn, JUMP_LABEL (jump_insn)); |
9c7e2978 RK |
4128 | slots = num_delay_slots (jump_insn); |
4129 | if (slots >= XVECLEN (pat, 0) - 1) | |
4130 | { | |
4131 | for (i = 1; i < XVECLEN (pat, 0); i++) | |
4132 | if (! ( | |
4133 | #ifdef ANNUL_IFFALSE_SLOTS | |
4134 | (INSN_ANNULLED_BRANCH_P (jump_insn) | |
4135 | && INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) | |
4136 | ? eligible_for_annul_false (jump_insn, i - 1, | |
35523fce | 4137 | XVECEXP (pat, 0, i), flags) : |
9c7e2978 RK |
4138 | #endif |
4139 | #ifdef ANNUL_IFTRUE_SLOTS | |
4140 | (INSN_ANNULLED_BRANCH_P (jump_insn) | |
4141 | && ! INSN_FROM_TARGET_P (XVECEXP (pat, 0, i))) | |
4142 | ? eligible_for_annul_true (jump_insn, i - 1, | |
35523fce | 4143 | XVECEXP (pat, 0, i), flags) : |
9c7e2978 | 4144 | #endif |
35523fce | 4145 | eligible_for_delay (jump_insn, i -1, XVECEXP (pat, 0, i), flags))) |
9c7e2978 RK |
4146 | break; |
4147 | } | |
4148 | else | |
4149 | i = 0; | |
4150 | ||
4151 | if (i == XVECLEN (pat, 0)) | |
4152 | continue; | |
4153 | ||
4154 | /* We have to do something with this insn. If it is an unconditional | |
4155 | RETURN, delete the SEQUENCE and output the individual insns, | |
4156 | followed by the RETURN. Then set things up so we try to find | |
4157 | insns for its delay slots, if it needs some. */ | |
4158 | if (GET_CODE (PATTERN (jump_insn)) == RETURN) | |
4159 | { | |
4160 | rtx prev = PREV_INSN (insn); | |
4161 | ||
4162 | delete_insn (insn); | |
4163 | for (i = 1; i < XVECLEN (pat, 0); i++) | |
4164 | prev = emit_insn_after (PATTERN (XVECEXP (pat, 0, i)), prev); | |
4165 | ||
4166 | insn = emit_jump_insn_after (PATTERN (jump_insn), prev); | |
4167 | emit_barrier_after (insn); | |
4168 | ||
4169 | if (slots) | |
4170 | obstack_ptr_grow (&unfilled_slots_obstack, insn); | |
4171 | } | |
4172 | else | |
4173 | /* It is probably more efficient to keep this with its current | |
4174 | delay slot as a branch to a RETURN. */ | |
326f06f7 | 4175 | reorg_redirect_jump (jump_insn, real_return_label); |
9c7e2978 RK |
4176 | } |
4177 | ||
4178 | /* Now delete REAL_RETURN_LABEL if we never used it. Then try to fill any | |
4179 | new delay slots we have created. */ | |
4180 | if (--LABEL_NUSES (real_return_label) == 0) | |
4181 | delete_insn (real_return_label); | |
4182 | ||
4183 | fill_simple_delay_slots (first, 1); | |
4184 | fill_simple_delay_slots (first, 0); | |
4185 | } | |
4186 | #endif | |
4187 | \f | |
4188 | /* Try to find insns to place in delay slots. */ | |
4189 | ||
4190 | void | |
4191 | dbr_schedule (first, file) | |
4192 | rtx first; | |
4193 | FILE *file; | |
4194 | { | |
7bd80f37 | 4195 | rtx insn, next, epilogue_insn = 0; |
9c7e2978 RK |
4196 | int i; |
4197 | #if 0 | |
4198 | int old_flag_no_peephole = flag_no_peephole; | |
4199 | ||
4200 | /* Execute `final' once in prescan mode to delete any insns that won't be | |
4201 | used. Don't let final try to do any peephole optimization--it will | |
4202 | ruin dataflow information for this pass. */ | |
4203 | ||
4204 | flag_no_peephole = 1; | |
4205 | final (first, 0, NO_DEBUG, 1, 1); | |
4206 | flag_no_peephole = old_flag_no_peephole; | |
4207 | #endif | |
4208 | ||
c3b80729 JL |
4209 | /* If the current function has no insns other than the prologue and |
4210 | epilogue, then do not try to fill any delay slots. */ | |
4211 | if (n_basic_blocks == 0) | |
4212 | return; | |
4213 | ||
9c7e2978 RK |
4214 | /* Find the highest INSN_UID and allocate and initialize our map from |
4215 | INSN_UID's to position in code. */ | |
4216 | for (max_uid = 0, insn = first; insn; insn = NEXT_INSN (insn)) | |
7bd80f37 TW |
4217 | { |
4218 | if (INSN_UID (insn) > max_uid) | |
4219 | max_uid = INSN_UID (insn); | |
4220 | if (GET_CODE (insn) == NOTE | |
4221 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EPILOGUE_BEG) | |
4222 | epilogue_insn = insn; | |
4223 | } | |
9c7e2978 RK |
4224 | |
4225 | uid_to_ruid = (int *) alloca ((max_uid + 1) * sizeof (int *)); | |
4226 | for (i = 0, insn = first; insn; i++, insn = NEXT_INSN (insn)) | |
4227 | uid_to_ruid[INSN_UID (insn)] = i; | |
4228 | ||
4229 | /* Initialize the list of insns that need filling. */ | |
4230 | if (unfilled_firstobj == 0) | |
4231 | { | |
4232 | gcc_obstack_init (&unfilled_slots_obstack); | |
4233 | unfilled_firstobj = (rtx *) obstack_alloc (&unfilled_slots_obstack, 0); | |
4234 | } | |
4235 | ||
4236 | for (insn = next_active_insn (first); insn; insn = next_active_insn (insn)) | |
4237 | { | |
4238 | rtx target; | |
4239 | ||
4240 | INSN_ANNULLED_BRANCH_P (insn) = 0; | |
4241 | INSN_FROM_TARGET_P (insn) = 0; | |
4242 | ||
4243 | /* Skip vector tables. We can't get attributes for them. */ | |
4244 | if (GET_CODE (insn) == JUMP_INSN | |
4245 | && (GET_CODE (PATTERN (insn)) == ADDR_VEC | |
4246 | || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)) | |
4247 | continue; | |
4248 | ||
4249 | if (num_delay_slots (insn) > 0) | |
4250 | obstack_ptr_grow (&unfilled_slots_obstack, insn); | |
4251 | ||
4252 | /* Ensure all jumps go to the last of a set of consecutive labels. */ | |
3480bb98 JL |
4253 | if (GET_CODE (insn) == JUMP_INSN |
4254 | && (condjump_p (insn) || condjump_in_parallel_p (insn)) | |
9c7e2978 RK |
4255 | && JUMP_LABEL (insn) != 0 |
4256 | && ((target = prev_label (next_active_insn (JUMP_LABEL (insn)))) | |
4257 | != JUMP_LABEL (insn))) | |
4258 | redirect_jump (insn, target); | |
4259 | } | |
4260 | ||
4261 | /* Indicate what resources are required to be valid at the end of the current | |
4262 | function. The condition code never is and memory always is. If the | |
4263 | frame pointer is needed, it is and so is the stack pointer unless | |
4264 | EXIT_IGNORE_STACK is non-zero. If the frame pointer is not needed, the | |
64af12fd RS |
4265 | stack pointer is. Registers used to return the function value are |
4266 | needed. Registers holding global variables are needed. */ | |
9c7e2978 RK |
4267 | |
4268 | end_of_function_needs.cc = 0; | |
4269 | end_of_function_needs.memory = 1; | |
8eae5ed6 | 4270 | end_of_function_needs.unch_memory = 0; |
9c7e2978 RK |
4271 | CLEAR_HARD_REG_SET (end_of_function_needs.regs); |
4272 | ||
4273 | if (frame_pointer_needed) | |
4274 | { | |
4275 | SET_HARD_REG_BIT (end_of_function_needs.regs, FRAME_POINTER_REGNUM); | |
b07ff75d DE |
4276 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM |
4277 | SET_HARD_REG_BIT (end_of_function_needs.regs, HARD_FRAME_POINTER_REGNUM); | |
4278 | #endif | |
9c7e2978 RK |
4279 | #ifdef EXIT_IGNORE_STACK |
4280 | if (! EXIT_IGNORE_STACK) | |
4281 | #endif | |
4282 | SET_HARD_REG_BIT (end_of_function_needs.regs, STACK_POINTER_REGNUM); | |
4283 | } | |
4284 | else | |
4285 | SET_HARD_REG_BIT (end_of_function_needs.regs, STACK_POINTER_REGNUM); | |
4286 | ||
4287 | if (current_function_return_rtx != 0 | |
4288 | && GET_CODE (current_function_return_rtx) == REG) | |
4289 | mark_referenced_resources (current_function_return_rtx, | |
674345b1 | 4290 | &end_of_function_needs, 1); |
9c7e2978 | 4291 | |
64af12fd RS |
4292 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
4293 | if (global_regs[i]) | |
4294 | SET_HARD_REG_BIT (end_of_function_needs.regs, i); | |
4295 | ||
7bd80f37 TW |
4296 | /* The registers required to be live at the end of the function are |
4297 | represented in the flow information as being dead just prior to | |
4298 | reaching the end of the function. For example, the return of a value | |
4299 | might be represented by a USE of the return register immediately | |
4300 | followed by an unconditional jump to the return label where the | |
4301 | return label is the end of the RTL chain. The end of the RTL chain | |
4302 | is then taken to mean that the return register is live. | |
4303 | ||
4304 | This sequence is no longer maintained when epilogue instructions are | |
4305 | added to the RTL chain. To reconstruct the original meaning, the | |
4306 | start of the epilogue (NOTE_INSN_EPILOGUE_BEG) is regarded as the | |
4307 | point where these registers become live (start_of_epilogue_needs). | |
4308 | If epilogue instructions are present, the registers set by those | |
4309 | instructions won't have been processed by flow. Thus, those | |
4310 | registers are additionally required at the end of the RTL chain | |
4311 | (end_of_function_needs). */ | |
4312 | ||
4313 | start_of_epilogue_needs = end_of_function_needs; | |
4314 | ||
4315 | while (epilogue_insn = next_nonnote_insn (epilogue_insn)) | |
674345b1 | 4316 | mark_set_resources (epilogue_insn, &end_of_function_needs, 0, 1); |
7bd80f37 | 4317 | |
9c7e2978 RK |
4318 | /* Show we haven't computed an end-of-function label yet. */ |
4319 | end_of_function_label = 0; | |
4320 | ||
4321 | /* Allocate and initialize the tables used by mark_target_live_regs. */ | |
4322 | target_hash_table | |
4323 | = (struct target_info **) alloca ((TARGET_HASH_PRIME | |
4324 | * sizeof (struct target_info *))); | |
780c3483 RK |
4325 | bzero ((char *) target_hash_table, |
4326 | TARGET_HASH_PRIME * sizeof (struct target_info *)); | |
9c7e2978 RK |
4327 | |
4328 | bb_ticks = (int *) alloca (n_basic_blocks * sizeof (int)); | |
780c3483 | 4329 | bzero ((char *) bb_ticks, n_basic_blocks * sizeof (int)); |
9c7e2978 RK |
4330 | |
4331 | /* Initialize the statistics for this function. */ | |
780c3483 RK |
4332 | bzero ((char *) num_insns_needing_delays, sizeof num_insns_needing_delays); |
4333 | bzero ((char *) num_filled_delays, sizeof num_filled_delays); | |
9c7e2978 RK |
4334 | |
4335 | /* Now do the delay slot filling. Try everything twice in case earlier | |
4336 | changes make more slots fillable. */ | |
4337 | ||
4338 | for (reorg_pass_number = 0; | |
4339 | reorg_pass_number < MAX_REORG_PASSES; | |
4340 | reorg_pass_number++) | |
4341 | { | |
4342 | fill_simple_delay_slots (first, 1); | |
4343 | fill_simple_delay_slots (first, 0); | |
4344 | fill_eager_delay_slots (first); | |
4345 | relax_delay_slots (first); | |
4346 | } | |
4347 | ||
4348 | /* Delete any USE insns made by update_block; subsequent passes don't need | |
4349 | them or know how to deal with them. */ | |
4350 | for (insn = first; insn; insn = next) | |
4351 | { | |
4352 | next = NEXT_INSN (insn); | |
4353 | ||
4354 | if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == USE | |
1422dce0 | 4355 | && GET_RTX_CLASS (GET_CODE (XEXP (PATTERN (insn), 0))) == 'i') |
9c7e2978 RK |
4356 | next = delete_insn (insn); |
4357 | } | |
4358 | ||
4359 | /* If we made an end of function label, indicate that it is now | |
4360 | safe to delete it by undoing our prior adjustment to LABEL_NUSES. | |
4361 | If it is now unused, delete it. */ | |
4362 | if (end_of_function_label && --LABEL_NUSES (end_of_function_label) == 0) | |
4363 | delete_insn (end_of_function_label); | |
4364 | ||
4365 | #ifdef HAVE_return | |
4366 | if (HAVE_return && end_of_function_label != 0) | |
4367 | make_return_insns (first); | |
4368 | #endif | |
4369 | ||
4370 | obstack_free (&unfilled_slots_obstack, unfilled_firstobj); | |
4371 | ||
4372 | /* It is not clear why the line below is needed, but it does seem to be. */ | |
4373 | unfilled_firstobj = (rtx *) obstack_alloc (&unfilled_slots_obstack, 0); | |
4374 | ||
bdac5f58 TW |
4375 | /* Reposition the prologue and epilogue notes in case we moved the |
4376 | prologue/epilogue insns. */ | |
4377 | reposition_prologue_and_epilogue_notes (first); | |
4378 | ||
9c7e2978 RK |
4379 | if (file) |
4380 | { | |
4381 | register int i, j, need_comma; | |
4382 | ||
4383 | for (reorg_pass_number = 0; | |
4384 | reorg_pass_number < MAX_REORG_PASSES; | |
4385 | reorg_pass_number++) | |
4386 | { | |
4387 | fprintf (file, ";; Reorg pass #%d:\n", reorg_pass_number + 1); | |
4388 | for (i = 0; i < NUM_REORG_FUNCTIONS; i++) | |
4389 | { | |
4390 | need_comma = 0; | |
4391 | fprintf (file, ";; Reorg function #%d\n", i); | |
4392 | ||
4393 | fprintf (file, ";; %d insns needing delay slots\n;; ", | |
4394 | num_insns_needing_delays[i][reorg_pass_number]); | |
4395 | ||
4396 | for (j = 0; j < MAX_DELAY_HISTOGRAM; j++) | |
4397 | if (num_filled_delays[i][j][reorg_pass_number]) | |
4398 | { | |
4399 | if (need_comma) | |
4400 | fprintf (file, ", "); | |
4401 | need_comma = 1; | |
4402 | fprintf (file, "%d got %d delays", | |
4403 | num_filled_delays[i][j][reorg_pass_number], j); | |
4404 | } | |
4405 | fprintf (file, "\n"); | |
4406 | } | |
4407 | } | |
4408 | } | |
4409 | } | |
4410 | #endif /* DELAY_SLOTS */ |