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d7429b6a | 1 | /* Data flow analysis for GNU compiler. |
a5cad800 | 2 | Copyright (C) 1987, 88, 92-98, 1999 Free Software Foundation, Inc. |
d7429b6a RK |
3 | |
4 | This file is part of GNU CC. | |
5 | ||
6 | GNU CC is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GNU CC is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GNU CC; see the file COPYING. If not, write to | |
a35311b0 RK |
18 | the Free Software Foundation, 59 Temple Place - Suite 330, |
19 | Boston, MA 02111-1307, USA. */ | |
d7429b6a RK |
20 | |
21 | ||
e881bb1b RH |
22 | /* This file contains the data flow analysis pass of the compiler. It |
23 | computes data flow information which tells combine_instructions | |
24 | which insns to consider combining and controls register allocation. | |
d7429b6a | 25 | |
e881bb1b RH |
26 | Additional data flow information that is too bulky to record is |
27 | generated during the analysis, and is used at that time to create | |
28 | autoincrement and autodecrement addressing. | |
d7429b6a RK |
29 | |
30 | The first step is dividing the function into basic blocks. | |
31 | find_basic_blocks does this. Then life_analysis determines | |
32 | where each register is live and where it is dead. | |
33 | ||
34 | ** find_basic_blocks ** | |
35 | ||
e881bb1b RH |
36 | find_basic_blocks divides the current function's rtl into basic |
37 | blocks and constructs the CFG. The blocks are recorded in the | |
38 | basic_block_info array; the CFG exists in the edge structures | |
39 | referenced by the blocks. | |
d7429b6a | 40 | |
e881bb1b | 41 | find_basic_blocks also finds any unreachable loops and deletes them. |
d7429b6a RK |
42 | |
43 | ** life_analysis ** | |
44 | ||
45 | life_analysis is called immediately after find_basic_blocks. | |
46 | It uses the basic block information to determine where each | |
47 | hard or pseudo register is live. | |
48 | ||
49 | ** live-register info ** | |
50 | ||
51 | The information about where each register is live is in two parts: | |
e881bb1b | 52 | the REG_NOTES of insns, and the vector basic_block->global_live_at_start. |
d7429b6a | 53 | |
e881bb1b RH |
54 | basic_block->global_live_at_start has an element for each basic |
55 | block, and the element is a bit-vector with a bit for each hard or | |
56 | pseudo register. The bit is 1 if the register is live at the | |
57 | beginning of the basic block. | |
d7429b6a RK |
58 | |
59 | Two types of elements can be added to an insn's REG_NOTES. | |
60 | A REG_DEAD note is added to an insn's REG_NOTES for any register | |
61 | that meets both of two conditions: The value in the register is not | |
62 | needed in subsequent insns and the insn does not replace the value in | |
63 | the register (in the case of multi-word hard registers, the value in | |
64 | each register must be replaced by the insn to avoid a REG_DEAD note). | |
65 | ||
66 | In the vast majority of cases, an object in a REG_DEAD note will be | |
67 | used somewhere in the insn. The (rare) exception to this is if an | |
68 | insn uses a multi-word hard register and only some of the registers are | |
69 | needed in subsequent insns. In that case, REG_DEAD notes will be | |
70 | provided for those hard registers that are not subsequently needed. | |
71 | Partial REG_DEAD notes of this type do not occur when an insn sets | |
72 | only some of the hard registers used in such a multi-word operand; | |
73 | omitting REG_DEAD notes for objects stored in an insn is optional and | |
74 | the desire to do so does not justify the complexity of the partial | |
75 | REG_DEAD notes. | |
76 | ||
77 | REG_UNUSED notes are added for each register that is set by the insn | |
78 | but is unused subsequently (if every register set by the insn is unused | |
79 | and the insn does not reference memory or have some other side-effect, | |
80 | the insn is deleted instead). If only part of a multi-word hard | |
81 | register is used in a subsequent insn, REG_UNUSED notes are made for | |
82 | the parts that will not be used. | |
83 | ||
84 | To determine which registers are live after any insn, one can | |
85 | start from the beginning of the basic block and scan insns, noting | |
86 | which registers are set by each insn and which die there. | |
87 | ||
88 | ** Other actions of life_analysis ** | |
89 | ||
90 | life_analysis sets up the LOG_LINKS fields of insns because the | |
91 | information needed to do so is readily available. | |
92 | ||
93 | life_analysis deletes insns whose only effect is to store a value | |
94 | that is never used. | |
95 | ||
96 | life_analysis notices cases where a reference to a register as | |
97 | a memory address can be combined with a preceding or following | |
98 | incrementation or decrementation of the register. The separate | |
99 | instruction to increment or decrement is deleted and the address | |
100 | is changed to a POST_INC or similar rtx. | |
101 | ||
102 | Each time an incrementing or decrementing address is created, | |
103 | a REG_INC element is added to the insn's REG_NOTES list. | |
104 | ||
105 | life_analysis fills in certain vectors containing information about | |
106 | register usage: reg_n_refs, reg_n_deaths, reg_n_sets, reg_live_length, | |
fdb8a883 JW |
107 | reg_n_calls_crosses and reg_basic_block. |
108 | ||
109 | life_analysis sets current_function_sp_is_unchanging if the function | |
110 | doesn't modify the stack pointer. */ | |
e881bb1b RH |
111 | |
112 | /* TODO: | |
113 | ||
114 | Split out from life_analysis: | |
115 | - local property discovery (bb->local_live, bb->local_set) | |
116 | - global property computation | |
117 | - log links creation | |
118 | - pre/post modify transformation | |
119 | */ | |
d7429b6a | 120 | \f |
d7429b6a | 121 | #include "config.h" |
670ee920 | 122 | #include "system.h" |
d7429b6a RK |
123 | #include "rtl.h" |
124 | #include "basic-block.h" | |
125 | #include "insn-config.h" | |
126 | #include "regs.h" | |
127 | #include "hard-reg-set.h" | |
128 | #include "flags.h" | |
129 | #include "output.h" | |
3d195391 | 130 | #include "except.h" |
2e107e9e | 131 | #include "toplev.h" |
79c9824e | 132 | #include "recog.h" |
e881bb1b | 133 | #include "insn-flags.h" |
d7429b6a RK |
134 | |
135 | #include "obstack.h" | |
136 | #define obstack_chunk_alloc xmalloc | |
137 | #define obstack_chunk_free free | |
138 | ||
e881bb1b RH |
139 | |
140 | /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function, | |
141 | the stack pointer does not matter. The value is tested only in | |
142 | functions that have frame pointers. | |
143 | No definition is equivalent to always zero. */ | |
144 | #ifndef EXIT_IGNORE_STACK | |
145 | #define EXIT_IGNORE_STACK 0 | |
146 | #endif | |
147 | ||
421382ac | 148 | |
7eb136d6 MM |
149 | /* The contents of the current function definition are allocated |
150 | in this obstack, and all are freed at the end of the function. | |
151 | For top-level functions, this is temporary_obstack. | |
152 | Separate obstacks are made for nested functions. */ | |
153 | ||
154 | extern struct obstack *function_obstack; | |
155 | ||
d7429b6a RK |
156 | /* List of labels that must never be deleted. */ |
157 | extern rtx forced_labels; | |
158 | ||
e881bb1b | 159 | /* Number of basic blocks in the current function. */ |
d7429b6a | 160 | |
e881bb1b | 161 | int n_basic_blocks; |
d7429b6a | 162 | |
e881bb1b | 163 | /* The basic block array. */ |
d7429b6a | 164 | |
e881bb1b | 165 | varray_type basic_block_info; |
d7429b6a | 166 | |
e881bb1b | 167 | /* The special entry and exit blocks. */ |
d7429b6a | 168 | |
e881bb1b RH |
169 | struct basic_block_def entry_exit_blocks[2] = |
170 | { | |
171 | { | |
172 | NULL, /* head */ | |
173 | NULL, /* end */ | |
174 | NULL, /* pred */ | |
175 | NULL, /* succ */ | |
176 | NULL, /* local_set */ | |
177 | NULL, /* global_live_at_start */ | |
178 | NULL, /* global_live_at_end */ | |
179 | NULL, /* aux */ | |
180 | ENTRY_BLOCK, /* index */ | |
181 | 0 /* loop_depth */ | |
182 | }, | |
183 | { | |
184 | NULL, /* head */ | |
185 | NULL, /* end */ | |
186 | NULL, /* pred */ | |
187 | NULL, /* succ */ | |
188 | NULL, /* local_set */ | |
189 | NULL, /* global_live_at_start */ | |
190 | NULL, /* global_live_at_end */ | |
191 | NULL, /* aux */ | |
192 | EXIT_BLOCK, /* index */ | |
193 | 0 /* loop_depth */ | |
194 | } | |
195 | }; | |
d7429b6a | 196 | |
56744d1a JL |
197 | /* Nonzero if the second flow pass has completed. */ |
198 | int flow2_completed; | |
199 | ||
d7429b6a RK |
200 | /* Maximum register number used in this function, plus one. */ |
201 | ||
202 | int max_regno; | |
203 | ||
b1f21e0a | 204 | /* Indexed by n, giving various register information */ |
d7429b6a | 205 | |
6feacd09 | 206 | varray_type reg_n_info; |
d7429b6a | 207 | |
a494747c MM |
208 | /* Size of the reg_n_info table. */ |
209 | ||
210 | unsigned int reg_n_max; | |
211 | ||
d7429b6a RK |
212 | /* Element N is the next insn that uses (hard or pseudo) register number N |
213 | within the current basic block; or zero, if there is no such insn. | |
214 | This is valid only during the final backward scan in propagate_block. */ | |
215 | ||
216 | static rtx *reg_next_use; | |
217 | ||
218 | /* Size of a regset for the current function, | |
219 | in (1) bytes and (2) elements. */ | |
220 | ||
221 | int regset_bytes; | |
222 | int regset_size; | |
223 | ||
d7429b6a | 224 | /* Regset of regs live when calls to `setjmp'-like functions happen. */ |
e881bb1b | 225 | /* ??? Does this exist only for the setjmp-clobbered warning message? */ |
d7429b6a RK |
226 | |
227 | regset regs_live_at_setjmp; | |
228 | ||
229 | /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers | |
230 | that have to go in the same hard reg. | |
231 | The first two regs in the list are a pair, and the next two | |
232 | are another pair, etc. */ | |
233 | rtx regs_may_share; | |
234 | ||
d7429b6a RK |
235 | /* Depth within loops of basic block being scanned for lifetime analysis, |
236 | plus one. This is the weight attached to references to registers. */ | |
237 | ||
238 | static int loop_depth; | |
239 | ||
240 | /* During propagate_block, this is non-zero if the value of CC0 is live. */ | |
241 | ||
242 | static int cc0_live; | |
243 | ||
db3a887b CB |
244 | /* During propagate_block, this contains a list of all the MEMs we are |
245 | tracking for dead store elimination. */ | |
d7429b6a | 246 | |
db3a887b | 247 | static rtx mem_set_list; |
d7429b6a RK |
248 | |
249 | /* Set of registers that may be eliminable. These are handled specially | |
250 | in updating regs_ever_live. */ | |
251 | ||
252 | static HARD_REG_SET elim_reg_set; | |
253 | ||
e881bb1b RH |
254 | /* The basic block structure for every insn, indexed by uid. */ |
255 | ||
256 | varray_type basic_block_for_insn; | |
257 | ||
258 | /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */ | |
259 | /* ??? Should probably be using LABEL_NUSES instead. It would take a | |
260 | bit of surgery to be able to use or co-opt the routines in jump. */ | |
261 | ||
262 | static rtx label_value_list; | |
263 | ||
264 | /* INSN_VOLATILE (insn) is 1 if the insn refers to anything volatile. */ | |
265 | ||
266 | #define INSN_VOLATILE(INSN) bitmap_bit_p (uid_volatile, INSN_UID (INSN)) | |
267 | #define SET_INSN_VOLATILE(INSN) bitmap_set_bit (uid_volatile, INSN_UID (INSN)) | |
268 | static bitmap uid_volatile; | |
269 | ||
d7429b6a | 270 | /* Forward declarations */ |
e881bb1b RH |
271 | static int count_basic_blocks PROTO((rtx)); |
272 | static rtx find_basic_blocks_1 PROTO((rtx, rtx*)); | |
273 | static void create_basic_block PROTO((int, rtx, rtx, rtx)); | |
274 | static void compute_bb_for_insn PROTO((varray_type, int)); | |
275 | static void clear_edges PROTO((void)); | |
276 | static void make_edges PROTO((rtx, rtx*)); | |
277 | static void make_edge PROTO((basic_block, basic_block, int)); | |
278 | static void make_label_edge PROTO((basic_block, rtx, int)); | |
279 | static void mark_critical_edges PROTO((void)); | |
280 | ||
281 | static void commit_one_edge_insertion PROTO((edge)); | |
282 | ||
421382ac | 283 | static void delete_unreachable_blocks PROTO((void)); |
e881bb1b RH |
284 | static void delete_eh_regions PROTO((void)); |
285 | static void delete_insn_chain PROTO((rtx, rtx)); | |
286 | static int delete_block PROTO((basic_block)); | |
287 | static void expunge_block PROTO((basic_block)); | |
288 | static rtx flow_delete_insn PROTO((rtx)); | |
289 | static int can_delete_label_p PROTO((rtx)); | |
290 | static void merge_blocks_nomove PROTO((basic_block, basic_block)); | |
291 | static int merge_blocks PROTO((edge,basic_block,basic_block)); | |
292 | static void tidy_fallthru_edge PROTO((edge,basic_block,basic_block)); | |
293 | static void calculate_loop_depth PROTO((rtx)); | |
294 | ||
dc2ede84 BS |
295 | static int set_noop_p PROTO((rtx)); |
296 | static int noop_move_p PROTO((rtx)); | |
e881bb1b | 297 | static void notice_stack_pointer_modification PROTO ((rtx, rtx)); |
dc2ede84 BS |
298 | static void record_volatile_insns PROTO((rtx)); |
299 | static void mark_regs_live_at_end PROTO((regset)); | |
e881bb1b RH |
300 | static void life_analysis_1 PROTO((rtx, int)); |
301 | static void init_regset_vector PROTO ((regset *, int, | |
302 | struct obstack *)); | |
303 | static void propagate_block PROTO((regset, rtx, rtx, int, | |
304 | regset, int)); | |
e398aa80 | 305 | static int insn_dead_p PROTO((rtx, regset, int, rtx)); |
e658434c RK |
306 | static int libcall_dead_p PROTO((rtx, regset, rtx, rtx)); |
307 | static void mark_set_regs PROTO((regset, regset, rtx, | |
308 | rtx, regset)); | |
309 | static void mark_set_1 PROTO((regset, regset, rtx, | |
310 | rtx, regset)); | |
1d300e19 | 311 | #ifdef AUTO_INC_DEC |
e658434c | 312 | static void find_auto_inc PROTO((regset, rtx, rtx)); |
e658434c RK |
313 | static int try_pre_increment_1 PROTO((rtx)); |
314 | static int try_pre_increment PROTO((rtx, rtx, HOST_WIDE_INT)); | |
1d300e19 KG |
315 | #endif |
316 | static void mark_used_regs PROTO((regset, regset, rtx, int, rtx)); | |
e658434c | 317 | void dump_flow_info PROTO((FILE *)); |
e881bb1b RH |
318 | static void dump_edge_info PROTO((FILE *, edge, int)); |
319 | ||
5ece9746 JL |
320 | static int_list_ptr alloc_int_list_node PROTO ((int_list_block **)); |
321 | static int_list_ptr add_int_list_node PROTO ((int_list_block **, | |
322 | int_list **, int)); | |
e881bb1b RH |
323 | |
324 | static void add_pred_succ PROTO ((int, int, int_list_ptr *, | |
325 | int_list_ptr *, int *, int *)); | |
326 | ||
4c649323 JL |
327 | static void count_reg_sets_1 PROTO ((rtx)); |
328 | static void count_reg_sets PROTO ((rtx)); | |
329 | static void count_reg_references PROTO ((rtx)); | |
fdb8a883 | 330 | static void notice_stack_pointer_modification PROTO ((rtx, rtx)); |
15e088b2 | 331 | static void invalidate_mems_from_autoinc PROTO ((rtx)); |
d7429b6a | 332 | \f |
5ece9746 | 333 | /* Find basic blocks of the current function. |
e881bb1b RH |
334 | F is the first insn of the function and NREGS the number of register |
335 | numbers in use. */ | |
d7429b6a RK |
336 | |
337 | void | |
9265dacf | 338 | find_basic_blocks (f, nregs, file) |
d7429b6a | 339 | rtx f; |
e881bb1b RH |
340 | int nregs ATTRIBUTE_UNUSED; |
341 | FILE *file ATTRIBUTE_UNUSED; | |
d7429b6a | 342 | { |
e881bb1b RH |
343 | rtx *bb_eh_end; |
344 | int max_uid; | |
d7429b6a | 345 | |
e881bb1b RH |
346 | /* Flush out existing data. */ |
347 | if (basic_block_info != NULL) | |
348 | { | |
349 | int i; | |
421382ac | 350 | |
e881bb1b | 351 | clear_edges (); |
d7429b6a | 352 | |
e881bb1b RH |
353 | /* Clear bb->aux on all extant basic blocks. We'll use this as a |
354 | tag for reuse during create_basic_block, just in case some pass | |
355 | copies around basic block notes improperly. */ | |
356 | for (i = 0; i < n_basic_blocks; ++i) | |
357 | BASIC_BLOCK (i)->aux = NULL; | |
d7429b6a | 358 | |
e881bb1b RH |
359 | VARRAY_FREE (basic_block_info); |
360 | } | |
27249135 | 361 | |
e881bb1b | 362 | n_basic_blocks = count_basic_blocks (f); |
27249135 | 363 | |
e881bb1b RH |
364 | /* Size the basic block table. The actual structures will be allocated |
365 | by find_basic_blocks_1, since we want to keep the structure pointers | |
366 | stable across calls to find_basic_blocks. */ | |
367 | /* ??? This whole issue would be much simpler if we called find_basic_blocks | |
368 | exactly once, and thereafter we don't have a single long chain of | |
369 | instructions at all until close to the end of compilation when we | |
370 | actually lay them out. */ | |
8cfe18d6 | 371 | |
e881bb1b RH |
372 | VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info"); |
373 | ||
374 | /* An array to record the active exception region at the end of each | |
375 | basic block. It is filled in by find_basic_blocks_1 for make_edges. */ | |
376 | bb_eh_end = (rtx *) alloca (n_basic_blocks * sizeof (rtx)); | |
d7429b6a | 377 | |
e881bb1b | 378 | label_value_list = find_basic_blocks_1 (f, bb_eh_end); |
5ece9746 | 379 | |
e881bb1b RH |
380 | /* Record the block to which an insn belongs. */ |
381 | /* ??? This should be done another way, by which (perhaps) a label is | |
382 | tagged directly with the basic block that it starts. It is used for | |
383 | more than that currently, but IMO that is the only valid use. */ | |
384 | ||
385 | max_uid = get_max_uid (); | |
d7429b6a | 386 | #ifdef AUTO_INC_DEC |
5ece9746 JL |
387 | /* Leave space for insns life_analysis makes in some cases for auto-inc. |
388 | These cases are rare, so we don't need too much space. */ | |
e881bb1b | 389 | max_uid += max_uid / 10; |
d7429b6a RK |
390 | #endif |
391 | ||
e881bb1b RH |
392 | VARRAY_BB_INIT (basic_block_for_insn, max_uid, "basic_block_for_insn"); |
393 | compute_bb_for_insn (basic_block_for_insn, max_uid); | |
394 | ||
395 | /* Discover the edges of our cfg. */ | |
d7429b6a | 396 | |
e881bb1b | 397 | make_edges (label_value_list, bb_eh_end); |
421382ac | 398 | |
e881bb1b RH |
399 | /* Delete unreachable blocks. */ |
400 | /* ??? Do this conditionally, or make this another entry point? */ | |
d7429b6a | 401 | |
e881bb1b RH |
402 | delete_unreachable_blocks (); |
403 | ||
404 | /* Mark critical edges. */ | |
405 | ||
406 | mark_critical_edges (); | |
407 | ||
408 | /* Discover the loop depth at the start of each basic block to aid | |
409 | register allocation. */ | |
410 | calculate_loop_depth (f); | |
411 | ||
412 | /* Kill the data we won't maintain. */ | |
413 | label_value_list = 0; | |
d7429b6a | 414 | } |
5ece9746 | 415 | |
e881bb1b | 416 | /* Count the basic blocks of the function. */ |
dc2ede84 | 417 | |
e881bb1b RH |
418 | static int |
419 | count_basic_blocks (f) | |
420 | rtx f; | |
421 | { | |
422 | register rtx insn; | |
423 | register RTX_CODE prev_code; | |
424 | register int count = 0; | |
425 | int eh_region = 0; | |
426 | int in_libcall_block = 0; | |
427 | int call_had_abnormal_edge = 0; | |
428 | rtx prev_call = NULL_RTX; | |
dc2ede84 | 429 | |
e881bb1b RH |
430 | prev_code = JUMP_INSN; |
431 | for (insn = f; insn; insn = NEXT_INSN (insn)) | |
432 | { | |
433 | register RTX_CODE code = GET_CODE (insn); | |
434 | ||
435 | /* Track when we are inside in LIBCALL block. */ | |
436 | if (GET_RTX_CLASS (code) == 'i' | |
437 | && find_reg_note (insn, REG_LIBCALL, NULL_RTX)) | |
438 | in_libcall_block = 1; | |
439 | ||
440 | if (code == CODE_LABEL | |
441 | || (GET_RTX_CLASS (code) == 'i' | |
442 | && (prev_code == JUMP_INSN | |
443 | || prev_code == BARRIER | |
444 | || (prev_code == CALL_INSN && call_had_abnormal_edge)))) | |
445 | { | |
446 | count++; | |
dc2ede84 | 447 | |
e881bb1b RH |
448 | /* If the previous insn was a call that did not create an |
449 | abnormal edge, we want to add a nop so that the CALL_INSN | |
450 | itself is not at basic_block_end. This allows us to | |
451 | easily distinguish between normal calls and those which | |
452 | create abnormal edges in the flow graph. */ | |
dc2ede84 | 453 | |
e881bb1b RH |
454 | if (count > 0 && prev_call != 0 && !call_had_abnormal_edge) |
455 | { | |
456 | rtx nop = gen_rtx_USE (VOIDmode, const0_rtx); | |
457 | emit_insn_after (nop, prev_call); | |
458 | } | |
459 | } | |
dc2ede84 | 460 | |
e881bb1b RH |
461 | /* Record whether this call created an edge. */ |
462 | if (code == CALL_INSN) | |
463 | { | |
464 | prev_call = insn; | |
465 | call_had_abnormal_edge = 0; | |
466 | if (nonlocal_goto_handler_labels) | |
467 | call_had_abnormal_edge = !in_libcall_block; | |
468 | else if (eh_region) | |
469 | { | |
470 | rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX); | |
471 | if (!note || XINT (XEXP (note, 0), 0) != 0) | |
472 | call_had_abnormal_edge = 1; | |
473 | } | |
474 | } | |
475 | else if (code != NOTE) | |
476 | prev_call = NULL_RTX; | |
477 | ||
478 | if (code != NOTE) | |
479 | prev_code = code; | |
480 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) | |
481 | ++eh_region; | |
482 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END) | |
483 | --eh_region; | |
484 | ||
485 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' | |
486 | && find_reg_note (insn, REG_RETVAL, NULL_RTX)) | |
487 | in_libcall_block = 0; | |
488 | } | |
489 | ||
490 | /* The rest of the compiler works a bit smoother when we don't have to | |
491 | check for the edge case of do-nothing functions with no basic blocks. */ | |
492 | if (count == 0) | |
493 | { | |
494 | emit_insn (gen_rtx_USE (VOIDmode, const0_rtx)); | |
495 | count = 1; | |
496 | } | |
497 | ||
498 | return count; | |
499 | } | |
dc2ede84 | 500 | |
d7429b6a RK |
501 | /* Find all basic blocks of the function whose first insn is F. |
502 | Store the correct data in the tables that describe the basic blocks, | |
503 | set up the chains of references for each CODE_LABEL, and | |
d7e4fe8b RS |
504 | delete any entire basic blocks that cannot be reached. |
505 | ||
e881bb1b RH |
506 | NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks |
507 | that are otherwise unreachable may be reachable with a non-local goto. | |
d7429b6a | 508 | |
e881bb1b RH |
509 | BB_EH_END is an array in which we record the list of exception regions |
510 | active at the end of every basic block. */ | |
8329b5ec | 511 | |
e881bb1b RH |
512 | static rtx |
513 | find_basic_blocks_1 (f, bb_eh_end) | |
514 | rtx f; | |
515 | rtx *bb_eh_end; | |
516 | { | |
517 | register rtx insn, next; | |
518 | int in_libcall_block = 0; | |
519 | int call_has_abnormal_edge = 0; | |
520 | int i = 0; | |
521 | rtx bb_note = NULL_RTX; | |
522 | rtx eh_list = NULL_RTX; | |
523 | rtx label_value_list = NULL_RTX; | |
524 | rtx head = NULL_RTX; | |
525 | rtx end = NULL_RTX; | |
526 | ||
527 | /* We process the instructions in a slightly different way than we did | |
528 | previously. This is so that we see a NOTE_BASIC_BLOCK after we have | |
529 | closed out the previous block, so that it gets attached at the proper | |
530 | place. Since this form should be equivalent to the previous, | |
531 | find_basic_blocks_0 continues to use the old form as a check. */ | |
d7429b6a | 532 | |
e881bb1b RH |
533 | for (insn = f; insn; insn = next) |
534 | { | |
535 | enum rtx_code code = GET_CODE (insn); | |
d7429b6a | 536 | |
e881bb1b | 537 | next = NEXT_INSN (insn); |
d7429b6a | 538 | |
e881bb1b RH |
539 | /* Track when we are inside in LIBCALL block. */ |
540 | if (GET_RTX_CLASS (code) == 'i' | |
541 | && find_reg_note (insn, REG_LIBCALL, NULL_RTX)) | |
542 | in_libcall_block = 1; | |
d7429b6a | 543 | |
e881bb1b | 544 | if (code == CALL_INSN) |
e658434c | 545 | { |
e881bb1b RH |
546 | /* Record whether this call created an edge. */ |
547 | call_has_abnormal_edge = 0; | |
548 | if (nonlocal_goto_handler_labels) | |
549 | call_has_abnormal_edge = !in_libcall_block; | |
550 | else if (eh_list) | |
e658434c | 551 | { |
e881bb1b RH |
552 | rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX); |
553 | if (!note || XINT (XEXP (note, 0), 0) != 0) | |
554 | call_has_abnormal_edge = 1; | |
5c35539b | 555 | } |
e658434c | 556 | } |
d7429b6a | 557 | |
e881bb1b | 558 | switch (code) |
e658434c | 559 | { |
e881bb1b RH |
560 | case NOTE: |
561 | { | |
562 | int kind = NOTE_LINE_NUMBER (insn); | |
563 | ||
564 | /* Keep a LIFO list of the currently active exception notes. */ | |
565 | if (kind == NOTE_INSN_EH_REGION_BEG) | |
566 | eh_list = gen_rtx_INSN_LIST (VOIDmode, insn, eh_list); | |
567 | else if (kind == NOTE_INSN_EH_REGION_END) | |
568 | eh_list = XEXP (eh_list, 1); | |
569 | ||
570 | /* Look for basic block notes with which to keep the | |
571 | basic_block_info pointers stable. Unthread the note now; | |
572 | we'll put it back at the right place in create_basic_block. | |
573 | Or not at all if we've already found a note in this block. */ | |
574 | else if (kind == NOTE_INSN_BASIC_BLOCK) | |
575 | { | |
576 | if (bb_note == NULL_RTX) | |
577 | bb_note = insn; | |
578 | next = flow_delete_insn (insn); | |
579 | } | |
e658434c | 580 | |
e881bb1b RH |
581 | break; |
582 | } | |
d7429b6a | 583 | |
e881bb1b RH |
584 | case CODE_LABEL: |
585 | /* A basic block starts at a label. If we've closed one off due | |
586 | to a barrier or some such, no need to do it again. */ | |
587 | if (head != NULL_RTX) | |
2ec1535d | 588 | { |
e881bb1b RH |
589 | /* While we now have edge lists with which other portions of |
590 | the compiler might determine a call ending a basic block | |
591 | does not imply an abnormal edge, it will be a bit before | |
592 | everything can be updated. So continue to emit a noop at | |
593 | the end of such a block. */ | |
594 | if (GET_CODE (end) == CALL_INSN) | |
595 | { | |
596 | rtx nop = gen_rtx_USE (VOIDmode, const0_rtx); | |
597 | end = emit_insn_after (nop, end); | |
598 | } | |
599 | ||
600 | bb_eh_end[i] = eh_list; | |
601 | create_basic_block (i++, head, end, bb_note); | |
602 | bb_note = NULL_RTX; | |
2ec1535d | 603 | } |
e881bb1b RH |
604 | head = end = insn; |
605 | break; | |
d06c6389 | 606 | |
e881bb1b RH |
607 | case JUMP_INSN: |
608 | /* A basic block ends at a jump. */ | |
609 | if (head == NULL_RTX) | |
610 | head = insn; | |
611 | else | |
612 | { | |
613 | /* ??? Make a special check for table jumps. The way this | |
614 | happens is truely and amazingly gross. We are about to | |
615 | create a basic block that contains just a code label and | |
616 | an addr*vec jump insn. Worse, an addr_diff_vec creates | |
617 | its own natural loop. | |
5c35539b | 618 | |
e881bb1b RH |
619 | Prevent this bit of brain damage, pasting things together |
620 | correctly in make_edges. | |
2c3a56ad | 621 | |
e881bb1b RH |
622 | The correct solution involves emitting the table directly |
623 | on the tablejump instruction as a note, or JUMP_LABEL. */ | |
e658434c | 624 | |
e881bb1b RH |
625 | if (GET_CODE (PATTERN (insn)) == ADDR_VEC |
626 | || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC) | |
627 | { | |
628 | head = end = NULL; | |
629 | n_basic_blocks--; | |
630 | break; | |
631 | } | |
632 | } | |
633 | end = insn; | |
634 | goto new_bb_inclusive; | |
d7429b6a | 635 | |
e881bb1b RH |
636 | case BARRIER: |
637 | /* A basic block ends at a barrier. It may be that an unconditional | |
638 | jump already closed the basic block -- no need to do it again. */ | |
639 | if (head == NULL_RTX) | |
640 | break; | |
d7429b6a | 641 | |
e881bb1b RH |
642 | /* While we now have edge lists with which other portions of the |
643 | compiler might determine a call ending a basic block does not | |
644 | imply an abnormal edge, it will be a bit before everything can | |
645 | be updated. So continue to emit a noop at the end of such a | |
646 | block. */ | |
647 | if (GET_CODE (end) == CALL_INSN) | |
648 | { | |
649 | rtx nop = gen_rtx_USE (VOIDmode, const0_rtx); | |
650 | end = emit_insn_after (nop, end); | |
651 | } | |
652 | goto new_bb_exclusive; | |
653 | ||
654 | case CALL_INSN: | |
655 | /* A basic block ends at a call that can either throw or | |
656 | do a non-local goto. */ | |
657 | if (call_has_abnormal_edge) | |
658 | { | |
659 | new_bb_inclusive: | |
660 | if (head == NULL_RTX) | |
661 | head = insn; | |
662 | end = insn; | |
663 | ||
664 | new_bb_exclusive: | |
665 | bb_eh_end[i] = eh_list; | |
666 | create_basic_block (i++, head, end, bb_note); | |
667 | head = end = NULL_RTX; | |
668 | bb_note = NULL_RTX; | |
669 | break; | |
670 | } | |
671 | /* FALLTHRU */ | |
d7429b6a | 672 | |
e881bb1b RH |
673 | default: |
674 | if (GET_RTX_CLASS (code) == 'i') | |
675 | { | |
676 | if (head == NULL_RTX) | |
677 | head = insn; | |
678 | end = insn; | |
679 | } | |
680 | break; | |
681 | } | |
d7429b6a | 682 | |
e881bb1b | 683 | if (GET_RTX_CLASS (code) == 'i') |
d7429b6a | 684 | { |
e881bb1b | 685 | rtx note; |
421382ac | 686 | |
e881bb1b RH |
687 | /* Make a list of all labels referred to other than by jumps |
688 | (which just don't have the REG_LABEL notes). | |
2ec1535d | 689 | |
e881bb1b RH |
690 | Make a special exception for labels followed by an ADDR*VEC, |
691 | as this would be a part of the tablejump setup code. | |
421382ac | 692 | |
e881bb1b RH |
693 | Make a special exception for the eh_return_stub_label, which |
694 | we know isn't part of any otherwise visible control flow. */ | |
695 | ||
696 | for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) | |
697 | if (REG_NOTE_KIND (note) == REG_LABEL) | |
698 | { | |
699 | rtx lab = XEXP (note, 0), next; | |
700 | ||
701 | if (lab == eh_return_stub_label) | |
702 | ; | |
703 | else if ((next = next_nonnote_insn (lab)) != NULL | |
704 | && GET_CODE (next) == JUMP_INSN | |
705 | && (GET_CODE (PATTERN (next)) == ADDR_VEC | |
706 | || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC)) | |
707 | ; | |
708 | else | |
709 | label_value_list | |
710 | = gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0), | |
711 | label_value_list); | |
d7429b6a | 712 | } |
e881bb1b RH |
713 | |
714 | if (find_reg_note (insn, REG_RETVAL, NULL_RTX)) | |
715 | in_libcall_block = 0; | |
d7429b6a | 716 | } |
e881bb1b | 717 | } |
d7429b6a | 718 | |
e881bb1b RH |
719 | if (head != NULL_RTX) |
720 | { | |
721 | bb_eh_end[i] = eh_list; | |
722 | create_basic_block (i++, head, end, bb_note); | |
723 | } | |
af14ce9c | 724 | |
e881bb1b RH |
725 | if (i != n_basic_blocks) |
726 | abort (); | |
af14ce9c | 727 | |
e881bb1b | 728 | return label_value_list; |
d7429b6a | 729 | } |
5ece9746 | 730 | |
e881bb1b RH |
731 | /* Create a new basic block consisting of the instructions between |
732 | HEAD and END inclusive. Reuses the note and basic block struct | |
733 | in BB_NOTE, if any. */ | |
5ece9746 | 734 | |
e881bb1b RH |
735 | static void |
736 | create_basic_block (index, head, end, bb_note) | |
737 | int index; | |
738 | rtx head, end, bb_note; | |
5ece9746 | 739 | { |
e881bb1b RH |
740 | basic_block bb; |
741 | ||
742 | if (bb_note | |
b3bf5bde | 743 | && ! RTX_INTEGRATED_P (bb_note) |
e881bb1b RH |
744 | && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL |
745 | && bb->aux == NULL) | |
5ece9746 | 746 | { |
e881bb1b RH |
747 | /* If we found an existing note, thread it back onto the chain. */ |
748 | ||
749 | if (GET_CODE (head) == CODE_LABEL) | |
750 | add_insn_after (bb_note, head); | |
751 | else | |
752 | { | |
753 | add_insn_before (bb_note, head); | |
754 | head = bb_note; | |
755 | } | |
5ece9746 | 756 | } |
e881bb1b RH |
757 | else |
758 | { | |
759 | /* Otherwise we must create a note and a basic block structure. | |
760 | Since we allow basic block structs in rtl, give the struct | |
761 | the same lifetime by allocating it off the function obstack | |
762 | rather than using malloc. */ | |
8329b5ec | 763 | |
e881bb1b RH |
764 | bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb)); |
765 | memset (bb, 0, sizeof (*bb)); | |
421382ac | 766 | |
e881bb1b RH |
767 | if (GET_CODE (head) == CODE_LABEL) |
768 | bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head); | |
769 | else | |
770 | { | |
771 | bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head); | |
772 | head = bb_note; | |
773 | } | |
774 | NOTE_BASIC_BLOCK (bb_note) = bb; | |
775 | } | |
776 | ||
777 | bb->head = head; | |
778 | bb->end = end; | |
779 | bb->index = index; | |
780 | BASIC_BLOCK (index) = bb; | |
781 | ||
782 | /* Tag the block so that we know it has been used when considering | |
783 | other basic block notes. */ | |
784 | bb->aux = bb; | |
421382ac | 785 | } |
e881bb1b RH |
786 | \f |
787 | /* Records the basic block struct in BB_FOR_INSN, for every instruction | |
788 | indexed by INSN_UID. MAX is the size of the array. */ | |
421382ac | 789 | |
421382ac | 790 | static void |
e881bb1b RH |
791 | compute_bb_for_insn (bb_for_insn, max) |
792 | varray_type bb_for_insn; | |
793 | int max; | |
421382ac | 794 | { |
e881bb1b | 795 | int i; |
421382ac | 796 | |
e881bb1b RH |
797 | for (i = 0; i < n_basic_blocks; ++i) |
798 | { | |
799 | basic_block bb = BASIC_BLOCK (i); | |
800 | rtx insn, end; | |
801 | ||
802 | end = bb->end; | |
803 | insn = bb->head; | |
804 | while (1) | |
805 | { | |
806 | int uid = INSN_UID (insn); | |
807 | if (uid < max) | |
808 | VARRAY_BB (bb_for_insn, uid) = bb; | |
809 | if (insn == end) | |
810 | break; | |
811 | insn = NEXT_INSN (insn); | |
812 | } | |
813 | } | |
421382ac BS |
814 | } |
815 | ||
e881bb1b | 816 | /* Free the memory associated with the edge structures. */ |
421382ac BS |
817 | |
818 | static void | |
e881bb1b | 819 | clear_edges () |
421382ac | 820 | { |
e881bb1b RH |
821 | int i; |
822 | edge n, e; | |
421382ac | 823 | |
e881bb1b | 824 | for (i = 0; i < n_basic_blocks; ++i) |
421382ac | 825 | { |
e881bb1b | 826 | basic_block bb = BASIC_BLOCK (i); |
421382ac | 827 | |
e881bb1b | 828 | for (e = bb->succ; e ; e = n) |
421382ac | 829 | { |
e881bb1b RH |
830 | n = e->succ_next; |
831 | free (e); | |
421382ac | 832 | } |
e881bb1b RH |
833 | |
834 | bb->succ = 0; | |
835 | bb->pred = 0; | |
836 | } | |
837 | ||
838 | for (e = ENTRY_BLOCK_PTR->succ; e ; e = n) | |
839 | { | |
840 | n = e->succ_next; | |
841 | free (e); | |
421382ac | 842 | } |
e881bb1b RH |
843 | |
844 | ENTRY_BLOCK_PTR->succ = 0; | |
845 | EXIT_BLOCK_PTR->pred = 0; | |
421382ac BS |
846 | } |
847 | ||
e881bb1b RH |
848 | /* Identify the edges between basic blocks. |
849 | ||
850 | NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks | |
851 | that are otherwise unreachable may be reachable with a non-local goto. | |
852 | ||
853 | BB_EH_END is an array indexed by basic block number in which we record | |
854 | the list of exception regions active at the end of the basic block. */ | |
855 | ||
dc2ede84 | 856 | static void |
e881bb1b RH |
857 | make_edges (label_value_list, bb_eh_end) |
858 | rtx label_value_list; | |
859 | rtx *bb_eh_end; | |
dc2ede84 | 860 | { |
e881bb1b RH |
861 | int i; |
862 | ||
863 | /* Assume no computed jump; revise as we create edges. */ | |
864 | current_function_has_computed_jump = 0; | |
865 | ||
866 | /* By nature of the way these get numbered, block 0 is always the entry. */ | |
867 | make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU); | |
dc2ede84 | 868 | |
e881bb1b | 869 | for (i = 0; i < n_basic_blocks; ++i) |
421382ac | 870 | { |
e881bb1b RH |
871 | basic_block bb = BASIC_BLOCK (i); |
872 | rtx insn, x, eh_list; | |
873 | enum rtx_code code; | |
4b523fc4 | 874 | int force_fallthru = 0; |
421382ac | 875 | |
e881bb1b RH |
876 | /* If we have asynchronous exceptions, scan the notes for all exception |
877 | regions active in the block. In the normal case, we only need the | |
878 | one active at the end of the block, which is bb_eh_end[i]. */ | |
421382ac | 879 | |
e881bb1b RH |
880 | eh_list = bb_eh_end[i]; |
881 | if (asynchronous_exceptions) | |
dc2ede84 | 882 | { |
e881bb1b | 883 | for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn)) |
dc2ede84 | 884 | { |
e881bb1b RH |
885 | if (GET_CODE (insn) == NOTE |
886 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END) | |
887 | eh_list = gen_rtx_INSN_LIST (VOIDmode, insn, eh_list); | |
dc2ede84 | 888 | } |
e881bb1b | 889 | } |
dc2ede84 | 890 | |
e881bb1b RH |
891 | /* Now examine the last instruction of the block, and discover the |
892 | ways we can leave the block. */ | |
893 | ||
894 | insn = bb->end; | |
895 | code = GET_CODE (insn); | |
896 | ||
897 | /* A branch. */ | |
898 | if (code == JUMP_INSN) | |
899 | { | |
900 | rtx tmp; | |
901 | ||
902 | /* ??? Recognize a tablejump and do the right thing. */ | |
903 | if ((tmp = JUMP_LABEL (insn)) != NULL_RTX | |
904 | && (tmp = NEXT_INSN (tmp)) != NULL_RTX | |
905 | && GET_CODE (tmp) == JUMP_INSN | |
906 | && (GET_CODE (PATTERN (tmp)) == ADDR_VEC | |
907 | || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC)) | |
908 | { | |
909 | rtvec vec; | |
910 | int j; | |
911 | ||
912 | if (GET_CODE (PATTERN (tmp)) == ADDR_VEC) | |
913 | vec = XVEC (PATTERN (tmp), 0); | |
914 | else | |
915 | vec = XVEC (PATTERN (tmp), 1); | |
916 | ||
917 | for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) | |
918 | make_label_edge (bb, XEXP (RTVEC_ELT (vec, j), 0), 0); | |
4b523fc4 RE |
919 | |
920 | /* Some targets (eg, ARM) emit a conditional jump that also | |
921 | contains the out-of-range target. Scan for these and | |
922 | add an edge if necessary. */ | |
923 | if ((tmp = single_set (insn)) != NULL | |
924 | && SET_DEST (tmp) == pc_rtx | |
925 | && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE | |
926 | && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF) | |
927 | make_label_edge (bb, XEXP (XEXP (SET_SRC (tmp), 2), 0), 0); | |
928 | ||
929 | #ifdef CASE_DROPS_THROUGH | |
930 | /* Silly VAXen. The ADDR_VEC is going to be in the way of | |
931 | us naturally detecting fallthru into the next block. */ | |
932 | force_fallthru = 1; | |
933 | #endif | |
e881bb1b RH |
934 | } |
935 | ||
936 | /* If this is a computed jump, then mark it as reaching | |
937 | everything on the label_value_list and forced_labels list. */ | |
938 | else if (computed_jump_p (insn)) | |
939 | { | |
dc2ede84 | 940 | current_function_has_computed_jump = 1; |
dc2ede84 | 941 | |
e881bb1b RH |
942 | for (x = label_value_list; x; x = XEXP (x, 1)) |
943 | make_label_edge (bb, XEXP (x, 0), EDGE_ABNORMAL); | |
944 | ||
dc2ede84 | 945 | for (x = forced_labels; x; x = XEXP (x, 1)) |
e881bb1b | 946 | make_label_edge (bb, XEXP (x, 0), EDGE_ABNORMAL); |
dc2ede84 BS |
947 | } |
948 | ||
e881bb1b RH |
949 | /* Returns create an exit out. */ |
950 | else if (returnjump_p (insn)) | |
951 | make_edge (bb, EXIT_BLOCK_PTR, 0); | |
952 | ||
953 | /* Otherwise, we have a plain conditional or unconditional jump. */ | |
954 | else | |
dc2ede84 | 955 | { |
e881bb1b RH |
956 | if (! JUMP_LABEL (insn)) |
957 | abort (); | |
958 | make_label_edge (bb, JUMP_LABEL (insn), 0); | |
959 | } | |
960 | } | |
961 | ||
962 | /* If this is a CALL_INSN, then mark it as reaching the active EH | |
963 | handler for this CALL_INSN. If we're handling asynchronous | |
964 | exceptions then any insn can reach any of the active handlers. | |
b472794d | 965 | |
e881bb1b | 966 | Also mark the CALL_INSN as reaching any nonlocal goto handler. */ |
b472794d | 967 | |
e881bb1b RH |
968 | else if (code == CALL_INSN || asynchronous_exceptions) |
969 | { | |
970 | int is_call = (code == CALL_INSN ? EDGE_ABNORMAL_CALL : 0); | |
971 | handler_info *ptr; | |
972 | ||
973 | /* Use REG_EH_RETHROW and REG_EH_REGION if available. */ | |
974 | /* ??? REG_EH_REGION is not generated presently. Is it | |
975 | inteded that there be multiple notes for the regions? | |
976 | or is my eh_list collection redundant with handler linking? */ | |
977 | ||
978 | x = find_reg_note (insn, REG_EH_RETHROW, 0); | |
979 | if (!x) | |
980 | x = find_reg_note (insn, REG_EH_REGION, 0); | |
981 | if (x) | |
982 | { | |
983 | if (XINT (XEXP (x, 0), 0) != 0) | |
dc2ede84 | 984 | { |
e881bb1b RH |
985 | ptr = get_first_handler (XINT (XEXP (x, 0), 0)); |
986 | while (ptr) | |
dc2ede84 | 987 | { |
e881bb1b RH |
988 | make_label_edge (bb, ptr->handler_label, |
989 | EDGE_ABNORMAL | EDGE_EH | is_call); | |
990 | ptr = ptr->next; | |
dc2ede84 BS |
991 | } |
992 | } | |
e881bb1b RH |
993 | } |
994 | else | |
995 | { | |
996 | for (x = eh_list; x; x = XEXP (x, 1)) | |
dc2ede84 | 997 | { |
e881bb1b RH |
998 | ptr = get_first_handler (NOTE_BLOCK_NUMBER (XEXP (x, 0))); |
999 | while (ptr) | |
1000 | { | |
1001 | make_label_edge (bb, ptr->handler_label, | |
1002 | EDGE_ABNORMAL | EDGE_EH | is_call); | |
1003 | ptr = ptr->next; | |
1004 | } | |
dc2ede84 | 1005 | } |
e881bb1b RH |
1006 | } |
1007 | ||
1008 | if (code == CALL_INSN && nonlocal_goto_handler_labels) | |
1009 | { | |
dc2ede84 BS |
1010 | /* ??? This could be made smarter: in some cases it's possible |
1011 | to tell that certain calls will not do a nonlocal goto. | |
1012 | ||
1013 | For example, if the nested functions that do the nonlocal | |
1014 | gotos do not have their addresses taken, then only calls to | |
1015 | those functions or to other nested functions that use them | |
1016 | could possibly do nonlocal gotos. */ | |
e881bb1b RH |
1017 | |
1018 | for (x = nonlocal_goto_handler_labels; x ; x = XEXP (x, 1)) | |
1019 | make_label_edge (bb, XEXP (x, 0), | |
1020 | EDGE_ABNORMAL | EDGE_ABNORMAL_CALL); | |
dc2ede84 BS |
1021 | } |
1022 | } | |
e881bb1b RH |
1023 | |
1024 | /* We know something about the structure of the function __throw in | |
1025 | libgcc2.c. It is the only function that ever contains eh_stub | |
1026 | labels. It modifies its return address so that the last block | |
1027 | returns to one of the eh_stub labels within it. So we have to | |
1028 | make additional edges in the flow graph. */ | |
1029 | if (i + 1 == n_basic_blocks && eh_return_stub_label != 0) | |
1030 | make_label_edge (bb, eh_return_stub_label, EDGE_EH); | |
1031 | ||
1032 | /* Find out if we can drop through to the next block. */ | |
1033 | insn = next_nonnote_insn (insn); | |
4b523fc4 | 1034 | if (!insn || (i + 1 == n_basic_blocks && force_fallthru)) |
e881bb1b RH |
1035 | make_edge (bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU); |
1036 | else if (i + 1 < n_basic_blocks) | |
1037 | { | |
1038 | rtx tmp = BLOCK_HEAD (i + 1); | |
1039 | if (GET_CODE (tmp) == NOTE) | |
1040 | tmp = next_nonnote_insn (tmp); | |
4b523fc4 | 1041 | if (force_fallthru || insn == tmp) |
e881bb1b RH |
1042 | make_edge (bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU); |
1043 | } | |
dc2ede84 | 1044 | } |
e881bb1b RH |
1045 | } |
1046 | ||
1047 | /* Create an edge between two basic blocks. FLAGS are auxiliary information | |
1048 | about the edge that is accumulated between calls. */ | |
1049 | ||
1050 | static void | |
1051 | make_edge (src, dst, flags) | |
1052 | basic_block src, dst; | |
1053 | int flags; | |
1054 | { | |
1055 | edge e; | |
1056 | ||
1057 | /* Make sure we don't add duplicate edges. */ | |
1058 | ||
1059 | for (e = src->succ; e ; e = e->succ_next) | |
1060 | if (e->dest == dst) | |
1061 | { | |
1062 | e->flags |= flags; | |
1063 | return; | |
1064 | } | |
1065 | ||
1066 | e = (edge) xcalloc (1, sizeof (*e)); | |
1067 | ||
1068 | e->succ_next = src->succ; | |
1069 | e->pred_next = dst->pred; | |
1070 | e->src = src; | |
1071 | e->dest = dst; | |
1072 | e->flags = flags; | |
1073 | ||
1074 | src->succ = e; | |
1075 | dst->pred = e; | |
1076 | } | |
1077 | ||
1078 | /* Create an edge from a basic block to a label. */ | |
1079 | ||
1080 | static void | |
1081 | make_label_edge (src, label, flags) | |
1082 | basic_block src; | |
1083 | rtx label; | |
1084 | int flags; | |
1085 | { | |
1086 | if (GET_CODE (label) != CODE_LABEL) | |
1087 | abort (); | |
1088 | ||
1089 | /* If the label was never emitted, this insn is junk, but avoid a | |
1090 | crash trying to refer to BLOCK_FOR_INSN (label). This can happen | |
1091 | as a result of a syntax error and a diagnostic has already been | |
1092 | printed. */ | |
1093 | ||
1094 | if (INSN_UID (label) == 0) | |
1095 | return; | |
1096 | ||
1097 | make_edge (src, BLOCK_FOR_INSN (label), flags); | |
1098 | } | |
e6cfb550 | 1099 | |
e881bb1b RH |
1100 | /* Identify critical edges and set the bits appropriately. */ |
1101 | static void | |
1102 | mark_critical_edges () | |
1103 | { | |
1104 | int i, n = n_basic_blocks; | |
1105 | basic_block bb; | |
1106 | ||
1107 | /* We begin with the entry block. This is not terribly important now, | |
1108 | but could be if a front end (Fortran) implemented alternate entry | |
1109 | points. */ | |
1110 | bb = ENTRY_BLOCK_PTR; | |
1111 | i = -1; | |
1112 | ||
1113 | while (1) | |
e6cfb550 | 1114 | { |
e881bb1b RH |
1115 | edge e; |
1116 | ||
1117 | /* (1) Critical edges must have a source with multiple successors. */ | |
1118 | if (bb->succ && bb->succ->succ_next) | |
1119 | { | |
1120 | for (e = bb->succ; e ; e = e->succ_next) | |
1121 | { | |
1122 | /* (2) Critical edges must have a destination with multiple | |
1123 | predecessors. Note that we know there is at least one | |
1124 | predecessor -- the edge we followed to get here. */ | |
1125 | if (e->dest->pred->pred_next) | |
1126 | e->flags |= EDGE_CRITICAL; | |
1127 | else | |
1128 | e->flags &= ~EDGE_CRITICAL; | |
1129 | } | |
1130 | } | |
1131 | else | |
1132 | { | |
1133 | for (e = bb->succ; e ; e = e->succ_next) | |
1134 | e->flags &= ~EDGE_CRITICAL; | |
1135 | } | |
1136 | ||
1137 | if (++i >= n) | |
1138 | break; | |
1139 | bb = BASIC_BLOCK (i); | |
e6cfb550 | 1140 | } |
e881bb1b RH |
1141 | } |
1142 | \f | |
1143 | /* Split a (typically critical) edge. Return the new block. | |
1144 | Abort on abnormal edges. | |
1145 | ||
1146 | ??? The code generally expects to be called on critical edges. | |
1147 | The case of a block ending in an unconditional jump to a | |
1148 | block with multiple predecessors is not handled optimally. */ | |
1149 | ||
1150 | basic_block | |
1151 | split_edge (edge_in) | |
1152 | edge edge_in; | |
1153 | { | |
1154 | basic_block old_pred, bb, old_succ; | |
1155 | edge edge_out; | |
1156 | rtx bb_note; | |
1157 | int i; | |
1158 | ||
1159 | /* Abnormal edges cannot be split. */ | |
1160 | if ((edge_in->flags & EDGE_ABNORMAL) != 0) | |
1161 | abort (); | |
1162 | ||
1163 | old_pred = edge_in->src; | |
1164 | old_succ = edge_in->dest; | |
1165 | ||
1166 | /* Remove the existing edge from the destination's pred list. */ | |
1167 | { | |
1168 | edge *pp; | |
1169 | for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next) | |
1170 | continue; | |
1171 | *pp = edge_in->pred_next; | |
1172 | } | |
1173 | ||
1174 | /* Create the new structures. */ | |
1175 | bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb)); | |
1176 | edge_out = (edge) xcalloc (1, sizeof (*edge_out)); | |
1177 | ||
1178 | memset (bb, 0, sizeof (*bb)); | |
1179 | bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack); | |
1180 | bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack); | |
1181 | bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack); | |
1182 | ||
1183 | /* ??? This info is likely going to be out of date very soon. */ | |
1184 | CLEAR_REG_SET (bb->local_set); | |
1185 | if (old_succ->global_live_at_start) | |
1186 | { | |
1187 | COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start); | |
1188 | COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start); | |
1189 | } | |
1190 | else | |
1191 | { | |
1192 | CLEAR_REG_SET (bb->global_live_at_start); | |
1193 | CLEAR_REG_SET (bb->global_live_at_end); | |
1194 | } | |
1195 | ||
1196 | /* Wire them up. */ | |
1197 | bb->pred = edge_in; | |
1198 | bb->succ = edge_out; | |
1199 | edge_in->dest = bb; | |
1200 | edge_out->src = bb; | |
1201 | edge_out->dest = old_succ; | |
1202 | ||
1203 | /* Tricky case -- if there existed a fallthru into the successor | |
1204 | (and we're not it) we must add a new unconditional jump around | |
1205 | the new block we're actually interested in. | |
1206 | ||
1207 | Further, if that edge is critical, this means a second new basic | |
1208 | block must be created to hold it. In order to simplify correct | |
1209 | insn placement, do this before we touch the existing basic block | |
1210 | ordering for the block we were really wanting. */ | |
1211 | if ((edge_in->flags & EDGE_FALLTHRU) == 0) | |
1212 | { | |
1213 | edge e; | |
1214 | for (e = old_succ->pred; e ; e = e->pred_next) | |
1215 | if (e->flags & EDGE_FALLTHRU) | |
1216 | break; | |
1217 | ||
1218 | if (e) | |
1219 | { | |
1220 | basic_block jump_block; | |
1221 | rtx pos; | |
1222 | ||
1223 | if ((e->flags & EDGE_CRITICAL) == 0) | |
1224 | { | |
1225 | /* Non critical -- we can simply add a jump to the end | |
1226 | of the existing predecessor. */ | |
1227 | jump_block = e->src; | |
1228 | pos = jump_block->end; | |
1229 | } | |
1230 | else | |
1231 | { | |
1232 | /* We need a new block to hold the jump. The simplest | |
1233 | way to do the bulk of the work here is to recursively | |
1234 | call ourselves. */ | |
1235 | jump_block = split_edge (e); | |
1236 | e = jump_block->succ; | |
1237 | pos = jump_block->head; | |
1238 | } | |
1239 | ||
1240 | /* Now add the jump insn... */ | |
1241 | pos = emit_jump_insn_after (gen_jump (old_succ->head), pos); | |
1242 | jump_block->end = pos; | |
1243 | emit_barrier_after (pos); | |
1244 | ||
1245 | /* ... and clear fallthru on the outgoing edge. */ | |
1246 | e->flags &= ~EDGE_FALLTHRU; | |
1247 | ||
1248 | /* Continue splitting the interesting edge. */ | |
1249 | } | |
1250 | } | |
1251 | ||
1252 | /* Place the new block just in front of the successor. */ | |
1253 | VARRAY_GROW (basic_block_info, ++n_basic_blocks); | |
1254 | for (i = n_basic_blocks - 1; i > old_succ->index; --i) | |
1255 | { | |
1256 | basic_block tmp = BASIC_BLOCK (i - 1); | |
1257 | BASIC_BLOCK (i) = tmp; | |
1258 | tmp->index = i; | |
1259 | } | |
1260 | BASIC_BLOCK (i) = bb; | |
1261 | bb->index = i; | |
1262 | ||
1263 | /* Create the basic block note. */ | |
1264 | bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head); | |
1265 | NOTE_BASIC_BLOCK (bb_note) = bb; | |
1266 | bb->head = bb->end = bb_note; | |
1267 | ||
1268 | /* Not quite simple -- for non-fallthru edges, we must adjust the | |
1269 | predecessor's jump instruction to target our new block. */ | |
1270 | if ((edge_in->flags & EDGE_FALLTHRU) == 0) | |
1271 | { | |
1272 | rtx tmp, insn = old_pred->end; | |
1273 | rtx old_label = old_succ->head; | |
1274 | rtx new_label = gen_label_rtx (); | |
1275 | ||
1276 | if (GET_CODE (insn) != JUMP_INSN) | |
1277 | abort (); | |
1278 | ||
1279 | /* ??? Recognize a tablejump and adjust all matching cases. */ | |
1280 | if ((tmp = JUMP_LABEL (insn)) != NULL_RTX | |
1281 | && (tmp = NEXT_INSN (tmp)) != NULL_RTX | |
1282 | && GET_CODE (tmp) == JUMP_INSN | |
1283 | && (GET_CODE (PATTERN (tmp)) == ADDR_VEC | |
1284 | || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC)) | |
1285 | { | |
1286 | rtvec vec; | |
1287 | int j; | |
1288 | ||
1289 | if (GET_CODE (PATTERN (tmp)) == ADDR_VEC) | |
1290 | vec = XVEC (PATTERN (tmp), 0); | |
1291 | else | |
1292 | vec = XVEC (PATTERN (tmp), 1); | |
1293 | ||
1294 | for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) | |
1295 | if (XEXP (RTVEC_ELT (vec, j), 0) == old_label) | |
1296 | { | |
1297 | RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label); | |
1298 | --LABEL_NUSES (old_label); | |
1299 | ++LABEL_NUSES (new_label); | |
1300 | } | |
1301 | } | |
1302 | else | |
1303 | { | |
1304 | /* This would have indicated an abnormal edge. */ | |
1305 | if (computed_jump_p (insn)) | |
1306 | abort (); | |
1307 | ||
1308 | /* A return instruction can't be redirected. */ | |
1309 | if (returnjump_p (insn)) | |
1310 | abort (); | |
1311 | ||
1312 | /* If the insn doesn't go where we think, we're confused. */ | |
1313 | if (JUMP_LABEL (insn) != old_label) | |
1314 | abort (); | |
1315 | ||
1316 | redirect_jump (insn, new_label); | |
1317 | } | |
1318 | ||
1319 | emit_label_before (new_label, bb_note); | |
1320 | bb->head = new_label; | |
1321 | } | |
1322 | ||
1323 | /* In all cases, the new block falls through to the successor. */ | |
1324 | edge_out->flags = EDGE_FALLTHRU; | |
1325 | ||
1326 | return bb; | |
1327 | } | |
1328 | ||
1329 | /* Queue instructions for insertion on an edge between two basic blocks. | |
1330 | The new instructions and basic blocks (if any) will not appear in the | |
1331 | CFG until commit_edge_insertions is called. */ | |
1332 | ||
1333 | void | |
1334 | insert_insn_on_edge (pattern, e) | |
1335 | rtx pattern; | |
1336 | edge e; | |
1337 | { | |
1338 | /* We cannot insert instructions on an abnormal critical edge. | |
1339 | It will be easier to find the culprit if we die now. */ | |
1340 | if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL)) | |
1341 | == (EDGE_ABNORMAL|EDGE_CRITICAL)) | |
1342 | abort (); | |
1343 | ||
1344 | if (e->insns == NULL_RTX) | |
1345 | start_sequence (); | |
1346 | else | |
1347 | push_to_sequence (e->insns); | |
1348 | ||
1349 | emit_insn (pattern); | |
1350 | ||
1351 | e->insns = get_insns (); | |
1352 | end_sequence(); | |
1353 | } | |
1354 | ||
1355 | /* Update the CFG for the instructions queued on edge E. */ | |
1356 | ||
1357 | static void | |
1358 | commit_one_edge_insertion (e) | |
1359 | edge e; | |
1360 | { | |
1361 | rtx before = NULL_RTX, after = NULL_RTX, tmp; | |
1362 | basic_block bb; | |
1363 | ||
1364 | /* Figure out where to put these things. If the destination has | |
1365 | one predecessor, insert there. Except for the exit block. */ | |
1366 | if (e->dest->pred->pred_next == NULL | |
1367 | && e->dest != EXIT_BLOCK_PTR) | |
1368 | { | |
1369 | bb = e->dest; | |
1370 | ||
1371 | /* Get the location correct wrt a code label, and "nice" wrt | |
1372 | a basic block note, and before everything else. */ | |
1373 | tmp = bb->head; | |
1374 | if (GET_CODE (tmp) == CODE_LABEL) | |
1375 | tmp = NEXT_INSN (tmp); | |
1376 | if (GET_CODE (tmp) == NOTE | |
1377 | && NOTE_LINE_NUMBER (tmp) == NOTE_INSN_BASIC_BLOCK) | |
1378 | tmp = NEXT_INSN (tmp); | |
1379 | if (tmp == bb->head) | |
1380 | before = tmp; | |
1381 | else | |
1382 | after = PREV_INSN (tmp); | |
1383 | } | |
1384 | ||
1385 | /* If the source has one successor and the edge is not abnormal, | |
1386 | insert there. Except for the entry block. */ | |
1387 | else if ((e->flags & EDGE_ABNORMAL) == 0 | |
1388 | && e->src->succ->succ_next == NULL | |
1389 | && e->src != ENTRY_BLOCK_PTR) | |
1390 | { | |
1391 | bb = e->src; | |
1392 | if (GET_CODE (bb->end) == JUMP_INSN) | |
1393 | { | |
1394 | /* ??? Is it possible to wind up with non-simple jumps? Perhaps | |
1395 | a jump with delay slots already filled? */ | |
1396 | if (! simplejump_p (bb->end)) | |
1397 | abort (); | |
1398 | ||
1399 | before = bb->end; | |
1400 | } | |
1401 | else | |
1402 | { | |
1403 | /* We'd better be fallthru, or we've lost track of what's what. */ | |
1404 | if ((e->flags & EDGE_FALLTHRU) == 0) | |
1405 | abort (); | |
1406 | ||
1407 | after = bb->end; | |
1408 | } | |
1409 | } | |
1410 | ||
1411 | /* Otherwise we must split the edge. */ | |
1412 | else | |
1413 | { | |
1414 | bb = split_edge (e); | |
1415 | after = bb->end; | |
1416 | } | |
1417 | ||
1418 | /* Now that we've found the spot, do the insertion. */ | |
1419 | tmp = e->insns; | |
1420 | e->insns = NULL_RTX; | |
1421 | if (before) | |
1422 | { | |
1423 | emit_insns_before (tmp, before); | |
1424 | if (before == bb->head) | |
1425 | bb->head = before; | |
1426 | } | |
1427 | else | |
1428 | { | |
1429 | tmp = emit_insns_after (tmp, after); | |
1430 | if (after == bb->end) | |
1431 | bb->end = tmp; | |
1432 | } | |
1433 | } | |
1434 | ||
1435 | /* Update the CFG for all queued instructions. */ | |
1436 | ||
1437 | void | |
1438 | commit_edge_insertions () | |
1439 | { | |
1440 | int i; | |
1441 | basic_block bb; | |
1442 | ||
1443 | i = -1; | |
1444 | bb = ENTRY_BLOCK_PTR; | |
1445 | while (1) | |
1446 | { | |
1447 | edge e, next; | |
1448 | ||
1449 | for (e = bb->succ; e ; e = next) | |
1450 | { | |
1451 | next = e->succ_next; | |
1452 | if (e->insns) | |
1453 | commit_one_edge_insertion (e); | |
1454 | } | |
1455 | ||
1456 | if (++i >= n_basic_blocks) | |
1457 | break; | |
1458 | bb = BASIC_BLOCK (i); | |
1459 | } | |
1460 | } | |
1461 | \f | |
1462 | /* Delete all unreachable basic blocks. */ | |
1463 | ||
1464 | static void | |
1465 | delete_unreachable_blocks () | |
1466 | { | |
1467 | basic_block *worklist, *tos; | |
1468 | int deleted_handler; | |
1469 | edge e; | |
1470 | int i, n; | |
1471 | ||
1472 | n = n_basic_blocks; | |
1473 | tos = worklist = (basic_block *) alloca (sizeof (basic_block) * n); | |
1474 | ||
1475 | /* Use basic_block->aux as a marker. Clear them all. */ | |
1476 | ||
1477 | for (i = 0; i < n; ++i) | |
1478 | BASIC_BLOCK (i)->aux = NULL; | |
1479 | ||
1480 | /* Add our starting points to the worklist. Almost always there will | |
1481 | be only one. It isn't inconcievable that we might one day directly | |
1482 | support Fortran alternate entry points. */ | |
1483 | ||
1484 | for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next) | |
aa3d4bf9 RH |
1485 | { |
1486 | *tos++ = e->dest; | |
1487 | ||
1488 | /* Mark the block with a handy non-null value. */ | |
1489 | e->dest->aux = e; | |
1490 | } | |
e881bb1b RH |
1491 | |
1492 | /* Iterate: find everything reachable from what we've already seen. */ | |
1493 | ||
1494 | while (tos != worklist) | |
1495 | { | |
1496 | basic_block b = *--tos; | |
1497 | ||
e881bb1b RH |
1498 | for (e = b->succ; e ; e = e->succ_next) |
1499 | if (!e->dest->aux) | |
aa3d4bf9 RH |
1500 | { |
1501 | *tos++ = e->dest; | |
1502 | e->dest->aux = e; | |
1503 | } | |
e881bb1b RH |
1504 | } |
1505 | ||
1506 | /* Delete all unreachable basic blocks. Count down so that we don't | |
1507 | interfere with the block renumbering that happens in delete_block. */ | |
1508 | ||
1509 | deleted_handler = 0; | |
1510 | ||
1511 | for (i = n - 1; i >= 0; --i) | |
1512 | { | |
1513 | basic_block b = BASIC_BLOCK (i); | |
1514 | ||
1515 | if (b->aux != NULL) | |
1516 | /* This block was found. Tidy up the mark. */ | |
1517 | b->aux = NULL; | |
1518 | else | |
1519 | deleted_handler |= delete_block (b); | |
1520 | } | |
1521 | ||
1522 | /* Fix up edges that now fall through, or rather should now fall through | |
1523 | but previously required a jump around now deleted blocks. Simplify | |
1524 | the search by only examining blocks numerically adjacent, since this | |
1525 | is how find_basic_blocks created them. */ | |
1526 | ||
1527 | for (i = 1; i < n_basic_blocks; ++i) | |
1528 | { | |
1529 | basic_block b = BASIC_BLOCK (i - 1); | |
1530 | basic_block c = BASIC_BLOCK (i); | |
1531 | edge s; | |
1532 | ||
1533 | /* We only need care for simple unconditional jumps, which implies | |
1534 | a single successor. */ | |
1535 | if ((s = b->succ) != NULL | |
1536 | && s->succ_next == NULL | |
1537 | && s->dest == c | |
1538 | && ! (s->flags & EDGE_FALLTHRU)) | |
1539 | tidy_fallthru_edge (s, b, c); | |
1540 | } | |
1541 | ||
1542 | /* Attempt to merge blocks as made possible by edge removal. If a block | |
1543 | has only one successor, and the successor has only one predecessor, | |
1544 | they may be combined. */ | |
1545 | ||
1546 | for (i = 0; i < n_basic_blocks; ) | |
1547 | { | |
1548 | basic_block c, b = BASIC_BLOCK (i); | |
1549 | edge s; | |
1550 | ||
1551 | /* A loop because chains of blocks might be combineable. */ | |
1552 | while ((s = b->succ) != NULL | |
1553 | && s->succ_next == NULL | |
1554 | && (c = s->dest) != EXIT_BLOCK_PTR | |
1555 | && c->pred->pred_next == NULL | |
1556 | && merge_blocks (s, b, c)) | |
1557 | continue; | |
1558 | ||
1559 | /* Don't get confused by the index shift caused by deleting blocks. */ | |
1560 | i = b->index + 1; | |
1561 | } | |
1562 | ||
1563 | /* If we deleted an exception handler, we may have EH region begin/end | |
1564 | blocks to remove as well. */ | |
1565 | if (deleted_handler) | |
1566 | delete_eh_regions (); | |
1567 | } | |
1568 | ||
1569 | /* Find EH regions for which there is no longer a handler, and delete them. */ | |
1570 | ||
1571 | static void | |
1572 | delete_eh_regions () | |
1573 | { | |
1574 | rtx insn; | |
1575 | ||
1576 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
1577 | if (GET_CODE (insn) == NOTE) | |
1578 | { | |
1579 | if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) || | |
1580 | (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)) | |
1581 | { | |
1582 | int num = CODE_LABEL_NUMBER (insn); | |
1583 | /* A NULL handler indicates a region is no longer needed */ | |
1584 | if (get_first_handler (num) == NULL) | |
1585 | { | |
1586 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
1587 | NOTE_SOURCE_FILE (insn) = 0; | |
1588 | } | |
1589 | } | |
1590 | } | |
1591 | } | |
1592 | ||
1593 | /* Return true if NOTE is not one of the ones that must be kept paired, | |
1594 | so that we may simply delete them. */ | |
1595 | ||
1596 | static int | |
1597 | delete_note_p (note) | |
1598 | rtx note; | |
1599 | { | |
1600 | return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED | |
1601 | || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK); | |
1602 | } | |
1603 | ||
1604 | /* Unlink a chain of insns between START and FINISH, leaving notes | |
1605 | that must be paired. */ | |
1606 | ||
1607 | static void | |
1608 | delete_insn_chain (start, finish) | |
1609 | rtx start, finish; | |
1610 | { | |
1611 | /* Unchain the insns one by one. It would be quicker to delete all | |
1612 | of these with a single unchaining, rather than one at a time, but | |
1613 | we need to keep the NOTE's. */ | |
1614 | ||
1615 | rtx next; | |
1616 | ||
1617 | while (1) | |
1618 | { | |
1619 | next = NEXT_INSN (start); | |
1620 | if (GET_CODE (start) != NOTE || delete_note_p (start)) | |
1621 | next = flow_delete_insn (start); | |
1622 | ||
1623 | if (start == finish) | |
1624 | break; | |
1625 | start = next; | |
1626 | } | |
1627 | } | |
1628 | ||
1629 | /* Delete the insns in a (non-live) block. We physically delete every | |
1630 | non-deleted-note insn, and update the flow graph appropriately. | |
1631 | ||
1632 | Return nonzero if we deleted an exception handler. */ | |
1633 | ||
1634 | /* ??? Preserving all such notes strikes me as wrong. It would be nice | |
1635 | to post-process the stream to remove empty blocks, loops, ranges, etc. */ | |
1636 | ||
1637 | static int | |
1638 | delete_block (b) | |
1639 | basic_block b; | |
1640 | { | |
1641 | int deleted_handler = 0; | |
1642 | rtx insn, end; | |
1643 | ||
1644 | /* If the head of this block is a CODE_LABEL, then it might be the | |
1645 | label for an exception handler which can't be reached. | |
1646 | ||
1647 | We need to remove the label from the exception_handler_label list | |
1648 | and remove the associated NOTE_EH_REGION_BEG and NOTE_EH_REGION_END | |
1649 | notes. */ | |
1650 | ||
1651 | insn = b->head; | |
1652 | if (GET_CODE (insn) == CODE_LABEL) | |
1653 | { | |
1654 | rtx x, *prev = &exception_handler_labels; | |
1655 | ||
1656 | for (x = exception_handler_labels; x; x = XEXP (x, 1)) | |
1657 | { | |
1658 | if (XEXP (x, 0) == insn) | |
1659 | { | |
1660 | /* Found a match, splice this label out of the EH label list. */ | |
1661 | *prev = XEXP (x, 1); | |
1662 | XEXP (x, 1) = NULL_RTX; | |
1663 | XEXP (x, 0) = NULL_RTX; | |
1664 | ||
1665 | /* Remove the handler from all regions */ | |
1666 | remove_handler (insn); | |
1667 | deleted_handler = 1; | |
1668 | break; | |
1669 | } | |
1670 | prev = &XEXP (x, 1); | |
1671 | } | |
1672 | ||
1673 | /* This label may be referenced by code solely for its value, or | |
1674 | referenced by static data, or something. We have determined | |
1675 | that it is not reachable, but cannot delete the label itself. | |
1676 | Save code space and continue to delete the balance of the block, | |
1677 | along with properly updating the cfg. */ | |
1678 | if (!can_delete_label_p (insn)) | |
1679 | { | |
1680 | /* If we've only got one of these, skip the whole deleting | |
1681 | insns thing. */ | |
1682 | if (insn == b->end) | |
1683 | goto no_delete_insns; | |
1684 | insn = NEXT_INSN (insn); | |
1685 | } | |
1686 | } | |
1687 | ||
1688 | /* Selectively unlink the insn chain. Include any BARRIER that may | |
1689 | follow the basic block. */ | |
1690 | end = next_nonnote_insn (b->end); | |
1691 | if (!end || GET_CODE (end) != BARRIER) | |
1692 | end = b->end; | |
1693 | delete_insn_chain (insn, end); | |
1694 | ||
1695 | no_delete_insns: | |
1696 | ||
1697 | /* Remove the edges into and out of this block. Note that there may | |
1698 | indeed be edges in, if we are removing an unreachable loop. */ | |
1699 | { | |
1700 | edge e, next, *q; | |
1701 | ||
1702 | for (e = b->pred; e ; e = next) | |
1703 | { | |
1704 | for (q = &e->src->succ; *q != e; q = &(*q)->succ_next) | |
1705 | continue; | |
1706 | *q = e->succ_next; | |
1707 | next = e->pred_next; | |
1708 | free (e); | |
1709 | } | |
1710 | for (e = b->succ; e ; e = next) | |
1711 | { | |
1712 | for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next) | |
1713 | continue; | |
1714 | *q = e->pred_next; | |
1715 | next = e->succ_next; | |
1716 | free (e); | |
1717 | } | |
1718 | ||
1719 | b->pred = NULL; | |
1720 | b->succ = NULL; | |
1721 | } | |
1722 | ||
1723 | /* Remove the basic block from the array, and compact behind it. */ | |
1724 | expunge_block (b); | |
1725 | ||
1726 | return deleted_handler; | |
1727 | } | |
1728 | ||
1729 | /* Remove block B from the basic block array and compact behind it. */ | |
1730 | ||
1731 | static void | |
1732 | expunge_block (b) | |
1733 | basic_block b; | |
1734 | { | |
1735 | int i, n = n_basic_blocks; | |
1736 | ||
1737 | for (i = b->index; i + 1 < n; ++i) | |
1738 | { | |
1739 | basic_block x = BASIC_BLOCK (i + 1); | |
1740 | BASIC_BLOCK (i) = x; | |
1741 | x->index = i; | |
1742 | } | |
1743 | ||
1744 | basic_block_info->num_elements--; | |
1745 | n_basic_blocks--; | |
1746 | } | |
1747 | ||
1748 | /* Delete INSN by patching it out. Return the next insn. */ | |
1749 | ||
1750 | static rtx | |
1751 | flow_delete_insn (insn) | |
1752 | rtx insn; | |
1753 | { | |
1754 | rtx prev = PREV_INSN (insn); | |
1755 | rtx next = NEXT_INSN (insn); | |
1756 | ||
1757 | PREV_INSN (insn) = NULL_RTX; | |
1758 | NEXT_INSN (insn) = NULL_RTX; | |
1759 | ||
1760 | if (prev) | |
1761 | NEXT_INSN (prev) = next; | |
1762 | if (next) | |
1763 | PREV_INSN (next) = prev; | |
1764 | else | |
1765 | set_last_insn (prev); | |
e6cfb550 | 1766 | |
e881bb1b RH |
1767 | /* If deleting a jump, decrement the use count of the label. Deleting |
1768 | the label itself should happen in the normal course of block merging. */ | |
1769 | if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn)) | |
1770 | LABEL_NUSES (JUMP_LABEL (insn))--; | |
1771 | ||
1772 | return next; | |
d7429b6a | 1773 | } |
8329b5ec | 1774 | |
e881bb1b RH |
1775 | /* True if a given label can be deleted. */ |
1776 | ||
1777 | static int | |
1778 | can_delete_label_p (label) | |
1779 | rtx label; | |
dc2ede84 | 1780 | { |
e881bb1b | 1781 | rtx x; |
dc2ede84 | 1782 | |
e881bb1b RH |
1783 | if (LABEL_PRESERVE_P (label)) |
1784 | return 0; | |
421382ac | 1785 | |
e881bb1b RH |
1786 | for (x = forced_labels; x ; x = XEXP (x, 1)) |
1787 | if (label == XEXP (x, 0)) | |
1788 | return 0; | |
1789 | for (x = label_value_list; x ; x = XEXP (x, 1)) | |
1790 | if (label == XEXP (x, 0)) | |
1791 | return 0; | |
1792 | for (x = exception_handler_labels; x ; x = XEXP (x, 1)) | |
1793 | if (label == XEXP (x, 0)) | |
1794 | return 0; | |
dc2ede84 | 1795 | |
e881bb1b RH |
1796 | return 1; |
1797 | } | |
421382ac | 1798 | |
e881bb1b RH |
1799 | /* Blocks A and B are to be merged into a single block. The insns |
1800 | are already contiguous, hence `nomove'. */ | |
421382ac | 1801 | |
e881bb1b RH |
1802 | static void |
1803 | merge_blocks_nomove (a, b) | |
1804 | basic_block a, b; | |
1805 | { | |
1806 | edge e; | |
1807 | rtx insn; | |
1808 | int done = 0; | |
421382ac | 1809 | |
e881bb1b RH |
1810 | /* If there was a jump out of A, delete it. */ |
1811 | if (GET_CODE (a->end) == JUMP_INSN) | |
1812 | { | |
1813 | /* If the jump was the only insn in A, turn the jump into a deleted | |
1814 | note, since we may yet not be able to merge the blocks. */ | |
1815 | if (a->end == a->head) | |
421382ac | 1816 | { |
e881bb1b RH |
1817 | PUT_CODE (a->head, NOTE); |
1818 | NOTE_LINE_NUMBER (a->head) = NOTE_INSN_DELETED; | |
1819 | NOTE_SOURCE_FILE (a->head) = 0; | |
1820 | } | |
1821 | else | |
1822 | { | |
1823 | rtx tmp = a->end; | |
86879c21 | 1824 | |
e881bb1b | 1825 | a->end = prev_nonnote_insn (tmp); |
86879c21 JL |
1826 | |
1827 | #ifdef HAVE_cc0 | |
1828 | /* If this was a conditional jump, we need to also delete | |
1829 | the insn that set cc0. */ | |
1830 | if (! simplejump_p (tmp) && condjump_p (tmp)) | |
1831 | { | |
1832 | PUT_CODE (PREV_INSN (tmp), NOTE); | |
1833 | NOTE_LINE_NUMBER (PREV_INSN (tmp)) = NOTE_INSN_DELETED; | |
1834 | NOTE_SOURCE_FILE (PREV_INSN (tmp)) = 0; | |
1835 | } | |
1836 | #endif | |
1837 | ||
e881bb1b | 1838 | flow_delete_insn (tmp); |
421382ac | 1839 | } |
421382ac | 1840 | } |
421382ac | 1841 | |
e881bb1b RH |
1842 | /* By definition, there should only be one successor of A, and that is |
1843 | B. Free that edge struct. */ | |
1844 | free (a->succ); | |
1845 | ||
1846 | /* Adjust the edges out of B for the new owner. */ | |
1847 | for (e = b->succ; e ; e = e->succ_next) | |
1848 | e->src = a; | |
1849 | a->succ = b->succ; | |
1850 | ||
1851 | /* If there was a CODE_LABEL beginning B, delete it. */ | |
1852 | insn = b->head; | |
1853 | if (GET_CODE (insn) == CODE_LABEL) | |
1854 | { | |
1855 | /* Detect basic blocks with nothing but a label. This can happen | |
1856 | in particular at the end of a function. */ | |
1857 | if (insn == b->end) | |
1858 | done = 1; | |
1859 | insn = flow_delete_insn (insn); | |
1860 | } | |
1861 | ||
1862 | /* Delete the basic block note. */ | |
1863 | if (GET_CODE (insn) == NOTE | |
1864 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_BASIC_BLOCK) | |
1865 | { | |
1866 | if (insn == b->end) | |
1867 | done = 1; | |
1868 | insn = flow_delete_insn (insn); | |
1869 | } | |
1870 | ||
1871 | /* Reassociate the insns of B with A. */ | |
1872 | if (!done) | |
1873 | { | |
1874 | BLOCK_FOR_INSN (insn) = a; | |
1875 | while (insn != b->end) | |
dc2ede84 | 1876 | { |
e881bb1b RH |
1877 | insn = NEXT_INSN (insn); |
1878 | BLOCK_FOR_INSN (insn) = a; | |
dc2ede84 | 1879 | } |
e881bb1b RH |
1880 | a->end = insn; |
1881 | } | |
1882 | ||
1883 | /* Compact the basic block array. */ | |
1884 | expunge_block (b); | |
dc2ede84 BS |
1885 | } |
1886 | ||
e881bb1b RH |
1887 | /* Attempt to merge basic blocks that are potentially non-adjacent. |
1888 | Return true iff the attempt succeeded. */ | |
dc2ede84 | 1889 | |
dc2ede84 | 1890 | static int |
e881bb1b RH |
1891 | merge_blocks (e, b, c) |
1892 | edge e; | |
1893 | basic_block b, c; | |
dc2ede84 | 1894 | { |
e881bb1b RH |
1895 | /* If B has a fallthru edge to C, no need to move anything. */ |
1896 | if (!(e->flags & EDGE_FALLTHRU)) | |
1897 | { | |
1898 | /* ??? From here on out we must make sure to not munge nesting | |
1899 | of exception regions and lexical blocks. Need to think about | |
1900 | these cases before this gets implemented. */ | |
1901 | return 0; | |
1902 | ||
1903 | /* If C has an outgoing fallthru, and B does not have an incoming | |
1904 | fallthru, move B before C. The later clause is somewhat arbitrary, | |
1905 | but avoids modifying blocks other than the two we've been given. */ | |
1906 | ||
1907 | /* Otherwise, move C after B. If C had a fallthru, which doesn't | |
1908 | happen to be the physical successor to B, insert an unconditional | |
1909 | branch. If C already ended with a conditional branch, the new | |
1910 | jump must go in a new basic block D. */ | |
1911 | } | |
dc2ede84 | 1912 | |
e881bb1b RH |
1913 | /* If a label still appears somewhere, we cannot delete the label, which |
1914 | means we cannot merge the blocks. We have still won a tad by tidying | |
1915 | the interface between the two blocks. */ | |
1916 | if (GET_CODE (c->head) == CODE_LABEL | |
1917 | && ! can_delete_label_p (c->head)) | |
dc2ede84 | 1918 | { |
e881bb1b RH |
1919 | tidy_fallthru_edge (e, b, c); |
1920 | return 0; | |
1921 | } | |
421382ac | 1922 | |
e881bb1b RH |
1923 | merge_blocks_nomove (b, c); |
1924 | return 1; | |
1925 | } | |
421382ac | 1926 | |
e881bb1b RH |
1927 | /* The given edge should potentially a fallthru edge. If that is in |
1928 | fact true, delete the unconditional jump and barriers that are in | |
1929 | the way. */ | |
1930 | ||
1931 | static void | |
1932 | tidy_fallthru_edge (e, b, c) | |
1933 | edge e; | |
1934 | basic_block b, c; | |
1935 | { | |
86a1db60 | 1936 | rtx q, h; |
e881bb1b RH |
1937 | |
1938 | /* ??? In a late-running flow pass, other folks may have deleted basic | |
1939 | blocks by nopping out blocks, leaving multiple BARRIERs between here | |
1940 | and the target label. They ought to be chastized and fixed. | |
1941 | ||
1942 | In the mean time, search for the last barrier in a sequence of | |
1943 | barriers and notes. */ | |
dc2ede84 | 1944 | |
e881bb1b | 1945 | q = NEXT_INSN (b->end); |
86a1db60 RH |
1946 | if (q && GET_CODE (q) == NOTE) |
1947 | q = next_nonnote_insn (q); | |
1948 | while (q && GET_CODE (q) == BARRIER) | |
1949 | q = next_nonnote_insn (q); | |
421382ac | 1950 | |
e881bb1b RH |
1951 | /* Assert that we now actually do fall through. */ |
1952 | h = c->head; | |
1953 | if (GET_CODE (h) == NOTE) | |
1954 | h = next_nonnote_insn (h); | |
1955 | if (q != h) | |
1956 | return; | |
421382ac | 1957 | |
e881bb1b RH |
1958 | /* Remove what will soon cease being the jump insn from the source block. |
1959 | If block B consisted only of this single jump, turn it into a deleted | |
1960 | note. */ | |
1961 | q = b->end; | |
1962 | if (GET_CODE (q) == JUMP_INSN) | |
421382ac | 1963 | { |
86a1db60 RH |
1964 | #ifdef HAVE_cc0 |
1965 | /* If this was a conditional jump, we need to also delete | |
1966 | the insn that set cc0. */ | |
1967 | if (! simplejump_p (q) && condjump_p (q)) | |
1968 | q = PREV_INSN (q); | |
1969 | #endif | |
1970 | ||
e881bb1b RH |
1971 | if (b->head == q) |
1972 | { | |
1973 | PUT_CODE (q, NOTE); | |
1974 | NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED; | |
1975 | NOTE_SOURCE_FILE (q) = 0; | |
1976 | } | |
e3f6ee23 | 1977 | else |
e881bb1b | 1978 | b->end = q = PREV_INSN (q); |
421382ac | 1979 | } |
421382ac | 1980 | |
e881bb1b | 1981 | /* Selectively unlink the sequence. */ |
86a1db60 RH |
1982 | if (q != PREV_INSN (c->head)) |
1983 | delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head)); | |
b7f7462b | 1984 | |
e881bb1b RH |
1985 | e->flags |= EDGE_FALLTHRU; |
1986 | } | |
dc2ede84 | 1987 | |
e881bb1b RH |
1988 | /* Discover and record the loop depth at the head of each basic block. */ |
1989 | ||
1990 | static void | |
1991 | calculate_loop_depth (insns) | |
1992 | rtx insns; | |
1993 | { | |
1994 | basic_block bb; | |
1995 | rtx insn; | |
1996 | int i = 0, depth = 1; | |
dc2ede84 | 1997 | |
e881bb1b RH |
1998 | bb = BASIC_BLOCK (i); |
1999 | for (insn = insns; insn ; insn = NEXT_INSN (insn)) | |
dc2ede84 | 2000 | { |
e881bb1b RH |
2001 | if (insn == bb->head) |
2002 | { | |
2003 | bb->loop_depth = depth; | |
2004 | if (++i >= n_basic_blocks) | |
dc2ede84 | 2005 | break; |
e881bb1b RH |
2006 | bb = BASIC_BLOCK (i); |
2007 | } | |
dc2ede84 | 2008 | |
e881bb1b RH |
2009 | if (GET_CODE (insn) == NOTE) |
2010 | { | |
2011 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) | |
2012 | depth++; | |
2013 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) | |
2014 | depth--; | |
2015 | ||
2016 | /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error. */ | |
2017 | if (depth == 0) | |
2018 | abort (); | |
2019 | } | |
2020 | } | |
dc2ede84 | 2021 | } |
d7429b6a | 2022 | \f |
5ece9746 JL |
2023 | /* Perform data flow analysis. |
2024 | F is the first insn of the function and NREGS the number of register numbers | |
2025 | in use. */ | |
2026 | ||
2027 | void | |
2028 | life_analysis (f, nregs, file) | |
2029 | rtx f; | |
2030 | int nregs; | |
2031 | FILE *file; | |
2032 | { | |
5ece9746 | 2033 | #ifdef ELIMINABLE_REGS |
ecb06768 | 2034 | register size_t i; |
5ece9746 JL |
2035 | static struct {int from, to; } eliminables[] = ELIMINABLE_REGS; |
2036 | #endif | |
2037 | ||
2038 | /* Record which registers will be eliminated. We use this in | |
2039 | mark_used_regs. */ | |
2040 | ||
2041 | CLEAR_HARD_REG_SET (elim_reg_set); | |
2042 | ||
2043 | #ifdef ELIMINABLE_REGS | |
2044 | for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++) | |
2045 | SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from); | |
2046 | #else | |
2047 | SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM); | |
2048 | #endif | |
2049 | ||
e881bb1b RH |
2050 | /* Allocate a bitmap to be filled in by record_volatile_insns. */ |
2051 | uid_volatile = BITMAP_ALLOCA (); | |
2052 | ||
db3a887b CB |
2053 | /* We want alias analysis information for local dead store elimination. */ |
2054 | init_alias_analysis (); | |
5ece9746 | 2055 | life_analysis_1 (f, nregs); |
db3a887b CB |
2056 | end_alias_analysis (); |
2057 | ||
5ece9746 JL |
2058 | if (file) |
2059 | dump_flow_info (file); | |
2060 | ||
e881bb1b | 2061 | BITMAP_FREE (uid_volatile); |
5ece9746 JL |
2062 | free_basic_block_vars (1); |
2063 | } | |
2064 | ||
2065 | /* Free the variables allocated by find_basic_blocks. | |
2066 | ||
e881bb1b | 2067 | KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */ |
5ece9746 JL |
2068 | |
2069 | void | |
2070 | free_basic_block_vars (keep_head_end_p) | |
2071 | int keep_head_end_p; | |
2072 | { | |
e881bb1b | 2073 | if (basic_block_for_insn) |
5ece9746 | 2074 | { |
e881bb1b RH |
2075 | VARRAY_FREE (basic_block_for_insn); |
2076 | basic_block_for_insn = NULL; | |
5ece9746 JL |
2077 | } |
2078 | ||
e881bb1b | 2079 | if (! keep_head_end_p) |
5ece9746 | 2080 | { |
e881bb1b RH |
2081 | clear_edges (); |
2082 | VARRAY_FREE (basic_block_info); | |
2083 | n_basic_blocks = 0; | |
5ece9746 JL |
2084 | } |
2085 | } | |
2086 | ||
dc2ede84 BS |
2087 | /* Return nonzero if the destination of SET equals the source. */ |
2088 | static int | |
2089 | set_noop_p (set) | |
2090 | rtx set; | |
2091 | { | |
2092 | rtx src = SET_SRC (set); | |
2093 | rtx dst = SET_DEST (set); | |
2094 | if (GET_CODE (src) == REG && GET_CODE (dst) == REG | |
2095 | && REGNO (src) == REGNO (dst)) | |
2096 | return 1; | |
2097 | if (GET_CODE (src) != SUBREG || GET_CODE (dst) != SUBREG | |
2098 | || SUBREG_WORD (src) != SUBREG_WORD (dst)) | |
2099 | return 0; | |
2100 | src = SUBREG_REG (src); | |
2101 | dst = SUBREG_REG (dst); | |
2102 | if (GET_CODE (src) == REG && GET_CODE (dst) == REG | |
2103 | && REGNO (src) == REGNO (dst)) | |
2104 | return 1; | |
2105 | return 0; | |
2106 | } | |
2107 | ||
2108 | /* Return nonzero if an insn consists only of SETs, each of which only sets a | |
2109 | value to itself. */ | |
2110 | static int | |
2111 | noop_move_p (insn) | |
2112 | rtx insn; | |
2113 | { | |
2114 | rtx pat = PATTERN (insn); | |
2115 | ||
2116 | /* Insns carrying these notes are useful later on. */ | |
2117 | if (find_reg_note (insn, REG_EQUAL, NULL_RTX)) | |
2118 | return 0; | |
2119 | ||
2120 | if (GET_CODE (pat) == SET && set_noop_p (pat)) | |
2121 | return 1; | |
2122 | ||
2123 | if (GET_CODE (pat) == PARALLEL) | |
2124 | { | |
2125 | int i; | |
2126 | /* If nothing but SETs of registers to themselves, | |
2127 | this insn can also be deleted. */ | |
2128 | for (i = 0; i < XVECLEN (pat, 0); i++) | |
2129 | { | |
2130 | rtx tem = XVECEXP (pat, 0, i); | |
2131 | ||
2132 | if (GET_CODE (tem) == USE | |
2133 | || GET_CODE (tem) == CLOBBER) | |
2134 | continue; | |
2135 | ||
2136 | if (GET_CODE (tem) != SET || ! set_noop_p (tem)) | |
2137 | return 0; | |
2138 | } | |
2139 | ||
2140 | return 1; | |
2141 | } | |
2142 | return 0; | |
2143 | } | |
2144 | ||
fdb8a883 JW |
2145 | static void |
2146 | notice_stack_pointer_modification (x, pat) | |
2147 | rtx x; | |
2148 | rtx pat ATTRIBUTE_UNUSED; | |
2149 | { | |
2150 | if (x == stack_pointer_rtx | |
2151 | /* The stack pointer is only modified indirectly as the result | |
2152 | of a push until later in flow. See the comments in rtl.texi | |
2153 | regarding Embedded Side-Effects on Addresses. */ | |
2154 | || (GET_CODE (x) == MEM | |
2155 | && (GET_CODE (XEXP (x, 0)) == PRE_DEC | |
2156 | || GET_CODE (XEXP (x, 0)) == PRE_INC | |
2157 | || GET_CODE (XEXP (x, 0)) == POST_DEC | |
2158 | || GET_CODE (XEXP (x, 0)) == POST_INC) | |
2159 | && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx)) | |
2160 | current_function_sp_is_unchanging = 0; | |
2161 | } | |
2162 | ||
dc2ede84 BS |
2163 | /* Record which insns refer to any volatile memory |
2164 | or for any reason can't be deleted just because they are dead stores. | |
fdb8a883 JW |
2165 | Also, delete any insns that copy a register to itself. |
2166 | And see if the stack pointer is modified. */ | |
dc2ede84 BS |
2167 | static void |
2168 | record_volatile_insns (f) | |
2169 | rtx f; | |
2170 | { | |
2171 | rtx insn; | |
2172 | for (insn = f; insn; insn = NEXT_INSN (insn)) | |
2173 | { | |
2174 | enum rtx_code code1 = GET_CODE (insn); | |
2175 | if (code1 == CALL_INSN) | |
e881bb1b | 2176 | SET_INSN_VOLATILE (insn); |
dc2ede84 BS |
2177 | else if (code1 == INSN || code1 == JUMP_INSN) |
2178 | { | |
2179 | if (GET_CODE (PATTERN (insn)) != USE | |
2180 | && volatile_refs_p (PATTERN (insn))) | |
e881bb1b | 2181 | SET_INSN_VOLATILE (insn); |
dc2ede84 BS |
2182 | |
2183 | /* A SET that makes space on the stack cannot be dead. | |
2184 | (Such SETs occur only for allocating variable-size data, | |
2185 | so they will always have a PLUS or MINUS according to the | |
2186 | direction of stack growth.) | |
2187 | Even if this function never uses this stack pointer value, | |
2188 | signal handlers do! */ | |
2189 | else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET | |
2190 | && SET_DEST (PATTERN (insn)) == stack_pointer_rtx | |
2191 | #ifdef STACK_GROWS_DOWNWARD | |
2192 | && GET_CODE (SET_SRC (PATTERN (insn))) == MINUS | |
2193 | #else | |
2194 | && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS | |
2195 | #endif | |
2196 | && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx) | |
e881bb1b | 2197 | SET_INSN_VOLATILE (insn); |
dc2ede84 BS |
2198 | |
2199 | /* Delete (in effect) any obvious no-op moves. */ | |
2200 | else if (noop_move_p (insn)) | |
2201 | { | |
2202 | PUT_CODE (insn, NOTE); | |
2203 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
2204 | NOTE_SOURCE_FILE (insn) = 0; | |
2205 | } | |
2206 | } | |
fdb8a883 JW |
2207 | |
2208 | /* Check if insn modifies the stack pointer. */ | |
2209 | if ( current_function_sp_is_unchanging | |
2210 | && GET_RTX_CLASS (GET_CODE (insn)) == 'i') | |
2211 | note_stores (PATTERN (insn), notice_stack_pointer_modification); | |
dc2ede84 BS |
2212 | } |
2213 | } | |
2214 | ||
2215 | /* Mark those regs which are needed at the end of the function as live | |
2216 | at the end of the last basic block. */ | |
2217 | static void | |
2218 | mark_regs_live_at_end (set) | |
2219 | regset set; | |
2220 | { | |
2221 | int i; | |
2222 | ||
e881bb1b RH |
2223 | /* If exiting needs the right stack value, consider the stack pointer |
2224 | live at the end of the function. */ | |
dc2ede84 BS |
2225 | if (! EXIT_IGNORE_STACK |
2226 | || (! FRAME_POINTER_REQUIRED | |
2227 | && ! current_function_calls_alloca | |
fdb8a883 JW |
2228 | && flag_omit_frame_pointer) |
2229 | || current_function_sp_is_unchanging) | |
e881bb1b RH |
2230 | { |
2231 | SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM); | |
2232 | } | |
dc2ede84 | 2233 | |
e881bb1b | 2234 | /* Mark the frame pointer if needed at the end of the function. If |
dc2ede84 BS |
2235 | we end up eliminating it, it will be removed from the live list |
2236 | of each basic block by reload. */ | |
2237 | ||
2238 | SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM); | |
2239 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM | |
2240 | /* If they are different, also mark the hard frame pointer as live */ | |
2241 | SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM); | |
2242 | #endif | |
2243 | ||
e881bb1b | 2244 | /* Mark all global registers, and all registers used by the epilogue |
dc2ede84 BS |
2245 | as being live at the end of the function since they may be |
2246 | referenced by our caller. */ | |
2247 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
2248 | if (global_regs[i] | |
2249 | #ifdef EPILOGUE_USES | |
2250 | || EPILOGUE_USES (i) | |
2251 | #endif | |
2252 | ) | |
2253 | SET_REGNO_REG_SET (set, i); | |
e881bb1b RH |
2254 | |
2255 | /* ??? Mark function return value here rather than as uses. */ | |
dc2ede84 BS |
2256 | } |
2257 | ||
d7429b6a RK |
2258 | /* Determine which registers are live at the start of each |
2259 | basic block of the function whose first insn is F. | |
2260 | NREGS is the number of registers used in F. | |
2261 | We allocate the vector basic_block_live_at_start | |
2262 | and the regsets that it points to, and fill them with the data. | |
2263 | regset_size and regset_bytes are also set here. */ | |
2264 | ||
2265 | static void | |
5ece9746 | 2266 | life_analysis_1 (f, nregs) |
d7429b6a RK |
2267 | rtx f; |
2268 | int nregs; | |
2269 | { | |
d7429b6a RK |
2270 | int first_pass; |
2271 | int changed; | |
d7429b6a | 2272 | register int i; |
6764d250 | 2273 | char save_regs_ever_live[FIRST_PSEUDO_REGISTER]; |
e881bb1b | 2274 | regset *new_live_at_end; |
d7429b6a RK |
2275 | |
2276 | struct obstack flow_obstack; | |
2277 | ||
2278 | gcc_obstack_init (&flow_obstack); | |
2279 | ||
2280 | max_regno = nregs; | |
2281 | ||
d7429b6a RK |
2282 | /* Allocate and zero out many data structures |
2283 | that will record the data from lifetime analysis. */ | |
2284 | ||
2285 | allocate_for_life_analysis (); | |
2286 | ||
2287 | reg_next_use = (rtx *) alloca (nregs * sizeof (rtx)); | |
e881bb1b | 2288 | memset (reg_next_use, 0, nregs * sizeof (rtx)); |
d7429b6a | 2289 | |
e881bb1b | 2290 | /* Set up regset-vectors used internally within this function. |
d7429b6a RK |
2291 | Their meanings are documented above, with their declarations. */ |
2292 | ||
e881bb1b RH |
2293 | new_live_at_end = (regset *) alloca ((n_basic_blocks + 1) * sizeof (regset)); |
2294 | init_regset_vector (new_live_at_end, n_basic_blocks + 1, &flow_obstack); | |
4c9a05bc | 2295 | |
e881bb1b RH |
2296 | /* Stick these vectors into the AUX field of the basic block, so that |
2297 | we don't have to keep going through the index. */ | |
d7429b6a | 2298 | |
e881bb1b RH |
2299 | for (i = 0; i < n_basic_blocks; ++i) |
2300 | BASIC_BLOCK (i)->aux = new_live_at_end[i]; | |
2301 | ENTRY_BLOCK_PTR->aux = new_live_at_end[i]; | |
d7429b6a | 2302 | |
fdb8a883 JW |
2303 | /* Assume that the stack pointer is unchanging if alloca hasn't been used. |
2304 | This will be cleared by record_volatile_insns if it encounters an insn | |
2305 | which modifies the stack pointer. */ | |
2306 | current_function_sp_is_unchanging = !current_function_calls_alloca; | |
2307 | ||
dc2ede84 | 2308 | record_volatile_insns (f); |
fe0f9c4b RK |
2309 | |
2310 | if (n_basic_blocks > 0) | |
2311 | { | |
e881bb1b RH |
2312 | regset theend; |
2313 | register edge e; | |
2314 | ||
2315 | theend = EXIT_BLOCK_PTR->global_live_at_start; | |
2316 | mark_regs_live_at_end (theend); | |
2317 | ||
2318 | /* Propogate this exit data to each of EXIT's predecessors. */ | |
2319 | for (e = EXIT_BLOCK_PTR->pred; e ; e = e->pred_next) | |
2320 | { | |
2321 | COPY_REG_SET (e->src->global_live_at_end, theend); | |
2322 | COPY_REG_SET ((regset) e->src->aux, theend); | |
2323 | } | |
dc2ede84 | 2324 | } |
d7429b6a | 2325 | |
e881bb1b RH |
2326 | /* The post-reload life analysis have (on a global basis) the same registers |
2327 | live as was computed by reload itself. | |
2328 | ||
2329 | Otherwise elimination offsets and such may be incorrect. | |
2330 | ||
2331 | Reload will make some registers as live even though they do not appear | |
2332 | in the rtl. */ | |
2333 | if (reload_completed) | |
2334 | memcpy (save_regs_ever_live, regs_ever_live, sizeof (regs_ever_live)); | |
2335 | memset (regs_ever_live, 0, sizeof regs_ever_live); | |
2336 | ||
d7429b6a RK |
2337 | /* Propagate life info through the basic blocks |
2338 | around the graph of basic blocks. | |
2339 | ||
2340 | This is a relaxation process: each time a new register | |
2341 | is live at the end of the basic block, we must scan the block | |
2342 | to determine which registers are, as a consequence, live at the beginning | |
2343 | of that block. These registers must then be marked live at the ends | |
2344 | of all the blocks that can transfer control to that block. | |
2345 | The process continues until it reaches a fixed point. */ | |
2346 | ||
2347 | first_pass = 1; | |
2348 | changed = 1; | |
2349 | while (changed) | |
2350 | { | |
2351 | changed = 0; | |
2352 | for (i = n_basic_blocks - 1; i >= 0; i--) | |
2353 | { | |
e881bb1b | 2354 | basic_block bb = BASIC_BLOCK (i); |
d7429b6a RK |
2355 | int consider = first_pass; |
2356 | int must_rescan = first_pass; | |
2357 | register int j; | |
2358 | ||
2359 | if (!first_pass) | |
2360 | { | |
2361 | /* Set CONSIDER if this block needs thinking about at all | |
2362 | (that is, if the regs live now at the end of it | |
2363 | are not the same as were live at the end of it when | |
2364 | we last thought about it). | |
2365 | Set must_rescan if it needs to be thought about | |
2366 | instruction by instruction (that is, if any additional | |
2367 | reg that is live at the end now but was not live there before | |
2368 | is one of the significant regs of this basic block). */ | |
2369 | ||
b5835272 | 2370 | EXECUTE_IF_AND_COMPL_IN_REG_SET |
e881bb1b | 2371 | ((regset) bb->aux, bb->global_live_at_end, 0, j, |
b5835272 RK |
2372 | { |
2373 | consider = 1; | |
e881bb1b | 2374 | if (REGNO_REG_SET_P (bb->local_set, j)) |
b5835272 RK |
2375 | { |
2376 | must_rescan = 1; | |
2377 | goto done; | |
2378 | } | |
2379 | }); | |
916b1701 | 2380 | done: |
d7429b6a RK |
2381 | if (! consider) |
2382 | continue; | |
2383 | } | |
2384 | ||
2385 | /* The live_at_start of this block may be changing, | |
2386 | so another pass will be required after this one. */ | |
2387 | changed = 1; | |
2388 | ||
2389 | if (! must_rescan) | |
2390 | { | |
2391 | /* No complete rescan needed; | |
2392 | just record those variables newly known live at end | |
2393 | as live at start as well. */ | |
e881bb1b RH |
2394 | IOR_AND_COMPL_REG_SET (bb->global_live_at_start, |
2395 | (regset) bb->aux, | |
2396 | bb->global_live_at_end); | |
916b1701 | 2397 | |
e881bb1b RH |
2398 | IOR_AND_COMPL_REG_SET (bb->global_live_at_end, |
2399 | (regset) bb->aux, | |
2400 | bb->global_live_at_end); | |
d7429b6a RK |
2401 | } |
2402 | else | |
2403 | { | |
2404 | /* Update the basic_block_live_at_start | |
2405 | by propagation backwards through the block. */ | |
e881bb1b RH |
2406 | COPY_REG_SET (bb->global_live_at_end, (regset) bb->aux); |
2407 | COPY_REG_SET (bb->global_live_at_start, | |
2408 | bb->global_live_at_end); | |
2409 | propagate_block (bb->global_live_at_start, | |
2410 | bb->head, bb->end, 0, | |
2411 | first_pass ? bb->local_set : (regset) 0, | |
d7429b6a RK |
2412 | i); |
2413 | } | |
2414 | ||
e881bb1b | 2415 | /* Update the new_live_at_end's of the block's predecessors. */ |
d7429b6a | 2416 | { |
e881bb1b | 2417 | register edge e; |
af14ce9c | 2418 | |
e881bb1b RH |
2419 | for (e = bb->pred; e ; e = e->pred_next) |
2420 | IOR_REG_SET ((regset) e->src->aux, bb->global_live_at_start); | |
d7429b6a | 2421 | } |
e881bb1b | 2422 | |
d7429b6a RK |
2423 | #ifdef USE_C_ALLOCA |
2424 | alloca (0); | |
2425 | #endif | |
2426 | } | |
2427 | first_pass = 0; | |
2428 | } | |
2429 | ||
2430 | /* The only pseudos that are live at the beginning of the function are | |
2431 | those that were not set anywhere in the function. local-alloc doesn't | |
2432 | know how to handle these correctly, so mark them as not local to any | |
2433 | one basic block. */ | |
2434 | ||
2435 | if (n_basic_blocks > 0) | |
e881bb1b | 2436 | EXECUTE_IF_SET_IN_REG_SET (BASIC_BLOCK (0)->global_live_at_start, |
916b1701 MM |
2437 | FIRST_PSEUDO_REGISTER, i, |
2438 | { | |
2439 | REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; | |
2440 | }); | |
d7429b6a | 2441 | |
e881bb1b RH |
2442 | /* Now the life information is accurate. Make one more pass over each |
2443 | basic block to delete dead stores, create autoincrement addressing | |
2444 | and record how many times each register is used, is set, or dies. */ | |
d7429b6a | 2445 | |
d7429b6a RK |
2446 | for (i = 0; i < n_basic_blocks; i++) |
2447 | { | |
e881bb1b RH |
2448 | basic_block bb = BASIC_BLOCK (i); |
2449 | ||
2450 | /* We start with global_live_at_end to determine which stores are | |
2451 | dead. This process is destructive, and we wish to preserve the | |
2452 | contents of global_live_at_end for posterity. Fortunately, | |
2453 | new_live_at_end, due to the way we converged on a solution, | |
2454 | contains a duplicate of global_live_at_end that we can kill. */ | |
2455 | propagate_block ((regset) bb->aux, bb->head, bb->end, 1, (regset) 0, i); | |
2456 | ||
d7429b6a RK |
2457 | #ifdef USE_C_ALLOCA |
2458 | alloca (0); | |
2459 | #endif | |
2460 | } | |
2461 | ||
e881bb1b RH |
2462 | /* We have a problem with any pseudoreg that lives across the setjmp. |
2463 | ANSI says that if a user variable does not change in value between | |
2464 | the setjmp and the longjmp, then the longjmp preserves it. This | |
2465 | includes longjmp from a place where the pseudo appears dead. | |
d7429b6a RK |
2466 | (In principle, the value still exists if it is in scope.) |
2467 | If the pseudo goes in a hard reg, some other value may occupy | |
2468 | that hard reg where this pseudo is dead, thus clobbering the pseudo. | |
2469 | Conclusion: such a pseudo must not go in a hard reg. */ | |
916b1701 MM |
2470 | EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp, |
2471 | FIRST_PSEUDO_REGISTER, i, | |
2472 | { | |
2473 | if (regno_reg_rtx[i] != 0) | |
2474 | { | |
2475 | REG_LIVE_LENGTH (i) = -1; | |
2476 | REG_BASIC_BLOCK (i) = -1; | |
2477 | } | |
2478 | }); | |
d7429b6a | 2479 | |
6764d250 BS |
2480 | /* Restore regs_ever_live that was provided by reload. */ |
2481 | if (reload_completed) | |
e881bb1b | 2482 | memcpy (regs_ever_live, save_regs_ever_live, sizeof (regs_ever_live)); |
67f0e213 | 2483 | |
e881bb1b | 2484 | free_regset_vector (new_live_at_end, n_basic_blocks); |
5f4f0e22 | 2485 | obstack_free (&flow_obstack, NULL_PTR); |
e881bb1b RH |
2486 | |
2487 | for (i = 0; i < n_basic_blocks; ++i) | |
2488 | BASIC_BLOCK (i)->aux = NULL; | |
2489 | ENTRY_BLOCK_PTR->aux = NULL; | |
d7429b6a RK |
2490 | } |
2491 | \f | |
2492 | /* Subroutines of life analysis. */ | |
2493 | ||
2494 | /* Allocate the permanent data structures that represent the results | |
2495 | of life analysis. Not static since used also for stupid life analysis. */ | |
2496 | ||
2497 | void | |
2498 | allocate_for_life_analysis () | |
2499 | { | |
2500 | register int i; | |
d7429b6a | 2501 | |
67f0e213 RK |
2502 | /* Recalculate the register space, in case it has grown. Old style |
2503 | vector oriented regsets would set regset_{size,bytes} here also. */ | |
2504 | allocate_reg_info (max_regno, FALSE, FALSE); | |
d7429b6a | 2505 | |
b1f21e0a MM |
2506 | /* Because both reg_scan and flow_analysis want to set up the REG_N_SETS |
2507 | information, explicitly reset it here. The allocation should have | |
2508 | already happened on the previous reg_scan pass. Make sure in case | |
2509 | some more registers were allocated. */ | |
d7429b6a | 2510 | for (i = 0; i < max_regno; i++) |
b1f21e0a | 2511 | REG_N_SETS (i) = 0; |
d7429b6a | 2512 | |
e881bb1b RH |
2513 | for (i = 0; i < n_basic_blocks; i++) |
2514 | { | |
2515 | basic_block bb = BASIC_BLOCK (i); | |
2516 | ||
2517 | bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack); | |
2518 | bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack); | |
2519 | bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack); | |
2520 | } | |
2521 | ||
2522 | ENTRY_BLOCK_PTR->global_live_at_end | |
2523 | = OBSTACK_ALLOC_REG_SET (function_obstack); | |
2524 | EXIT_BLOCK_PTR->global_live_at_start | |
2525 | = OBSTACK_ALLOC_REG_SET (function_obstack); | |
d7429b6a | 2526 | |
7eb136d6 MM |
2527 | regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack); |
2528 | CLEAR_REG_SET (regs_live_at_setjmp); | |
d7429b6a RK |
2529 | } |
2530 | ||
67f0e213 RK |
2531 | /* Make each element of VECTOR point at a regset. The vector has |
2532 | NELTS elements, and space is allocated from the ALLOC_OBSTACK | |
2533 | obstack. */ | |
d7429b6a | 2534 | |
04821e98 | 2535 | static void |
67f0e213 | 2536 | init_regset_vector (vector, nelts, alloc_obstack) |
d7429b6a | 2537 | regset *vector; |
d7429b6a | 2538 | int nelts; |
7eb136d6 | 2539 | struct obstack *alloc_obstack; |
d7429b6a RK |
2540 | { |
2541 | register int i; | |
d7429b6a RK |
2542 | |
2543 | for (i = 0; i < nelts; i++) | |
2544 | { | |
7eb136d6 MM |
2545 | vector[i] = OBSTACK_ALLOC_REG_SET (alloc_obstack); |
2546 | CLEAR_REG_SET (vector[i]); | |
d7429b6a RK |
2547 | } |
2548 | } | |
e658434c | 2549 | |
67f0e213 RK |
2550 | /* Release any additional space allocated for each element of VECTOR point |
2551 | other than the regset header itself. The vector has NELTS elements. */ | |
2552 | ||
2553 | void | |
2554 | free_regset_vector (vector, nelts) | |
2555 | regset *vector; | |
2556 | int nelts; | |
2557 | { | |
2558 | register int i; | |
2559 | ||
2560 | for (i = 0; i < nelts; i++) | |
2561 | FREE_REG_SET (vector[i]); | |
2562 | } | |
2563 | ||
d7429b6a RK |
2564 | /* Compute the registers live at the beginning of a basic block |
2565 | from those live at the end. | |
2566 | ||
2567 | When called, OLD contains those live at the end. | |
2568 | On return, it contains those live at the beginning. | |
2569 | FIRST and LAST are the first and last insns of the basic block. | |
2570 | ||
2571 | FINAL is nonzero if we are doing the final pass which is not | |
2572 | for computing the life info (since that has already been done) | |
2573 | but for acting on it. On this pass, we delete dead stores, | |
2574 | set up the logical links and dead-variables lists of instructions, | |
2575 | and merge instructions for autoincrement and autodecrement addresses. | |
2576 | ||
2577 | SIGNIFICANT is nonzero only the first time for each basic block. | |
2578 | If it is nonzero, it points to a regset in which we store | |
2579 | a 1 for each register that is set within the block. | |
2580 | ||
2581 | BNUM is the number of the basic block. */ | |
2582 | ||
2583 | static void | |
2584 | propagate_block (old, first, last, final, significant, bnum) | |
2585 | register regset old; | |
2586 | rtx first; | |
2587 | rtx last; | |
2588 | int final; | |
2589 | regset significant; | |
2590 | int bnum; | |
2591 | { | |
2592 | register rtx insn; | |
2593 | rtx prev; | |
2594 | regset live; | |
2595 | regset dead; | |
2596 | ||
e881bb1b RH |
2597 | /* Find the loop depth for this block. Ignore loop level changes in the |
2598 | middle of the basic block -- for register allocation purposes, the | |
2599 | important uses will be in the blocks wholely contained within the loop | |
2600 | not in the loop pre-header or post-trailer. */ | |
2601 | loop_depth = BASIC_BLOCK (bnum)->loop_depth; | |
d7429b6a | 2602 | |
7eb136d6 MM |
2603 | dead = ALLOCA_REG_SET (); |
2604 | live = ALLOCA_REG_SET (); | |
d7429b6a RK |
2605 | |
2606 | cc0_live = 0; | |
db3a887b | 2607 | mem_set_list = NULL_RTX; |
d7429b6a | 2608 | |
d7429b6a RK |
2609 | if (final) |
2610 | { | |
916b1701 | 2611 | register int i; |
d7429b6a | 2612 | |
d7429b6a | 2613 | /* Process the regs live at the end of the block. |
f8dd7f98 | 2614 | Mark them as not local to any one basic block. */ |
916b1701 MM |
2615 | EXECUTE_IF_SET_IN_REG_SET (old, 0, i, |
2616 | { | |
2617 | REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; | |
916b1701 | 2618 | }); |
d7429b6a RK |
2619 | } |
2620 | ||
2621 | /* Scan the block an insn at a time from end to beginning. */ | |
2622 | ||
2623 | for (insn = last; ; insn = prev) | |
2624 | { | |
2625 | prev = PREV_INSN (insn); | |
2626 | ||
8329b5ec | 2627 | if (GET_CODE (insn) == NOTE) |
d7429b6a | 2628 | { |
8329b5ec DE |
2629 | /* If this is a call to `setjmp' et al, |
2630 | warn if any non-volatile datum is live. */ | |
2631 | ||
2632 | if (final && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP) | |
916b1701 | 2633 | IOR_REG_SET (regs_live_at_setjmp, old); |
d7429b6a RK |
2634 | } |
2635 | ||
2636 | /* Update the life-status of regs for this insn. | |
2637 | First DEAD gets which regs are set in this insn | |
2638 | then LIVE gets which regs are used in this insn. | |
2639 | Then the regs live before the insn | |
2640 | are those live after, with DEAD regs turned off, | |
2641 | and then LIVE regs turned on. */ | |
2642 | ||
8329b5ec | 2643 | else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') |
d7429b6a RK |
2644 | { |
2645 | register int i; | |
5f4f0e22 | 2646 | rtx note = find_reg_note (insn, REG_RETVAL, NULL_RTX); |
d7429b6a | 2647 | int insn_is_dead |
e398aa80 | 2648 | = (insn_dead_p (PATTERN (insn), old, 0, REG_NOTES (insn)) |
d7429b6a RK |
2649 | /* Don't delete something that refers to volatile storage! */ |
2650 | && ! INSN_VOLATILE (insn)); | |
2651 | int libcall_is_dead | |
2652 | = (insn_is_dead && note != 0 | |
2653 | && libcall_dead_p (PATTERN (insn), old, note, insn)); | |
2654 | ||
2655 | /* If an instruction consists of just dead store(s) on final pass, | |
2656 | "delete" it by turning it into a NOTE of type NOTE_INSN_DELETED. | |
2657 | We could really delete it with delete_insn, but that | |
2658 | can cause trouble for first or last insn in a basic block. */ | |
b590bbfd | 2659 | if (final && insn_is_dead) |
d7429b6a RK |
2660 | { |
2661 | PUT_CODE (insn, NOTE); | |
2662 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
2663 | NOTE_SOURCE_FILE (insn) = 0; | |
2664 | ||
e5df1ea3 RK |
2665 | /* CC0 is now known to be dead. Either this insn used it, |
2666 | in which case it doesn't anymore, or clobbered it, | |
2667 | so the next insn can't use it. */ | |
2668 | cc0_live = 0; | |
2669 | ||
d7429b6a RK |
2670 | /* If this insn is copying the return value from a library call, |
2671 | delete the entire library call. */ | |
2672 | if (libcall_is_dead) | |
2673 | { | |
2674 | rtx first = XEXP (note, 0); | |
2675 | rtx p = insn; | |
2676 | while (INSN_DELETED_P (first)) | |
2677 | first = NEXT_INSN (first); | |
2678 | while (p != first) | |
2679 | { | |
2680 | p = PREV_INSN (p); | |
2681 | PUT_CODE (p, NOTE); | |
2682 | NOTE_LINE_NUMBER (p) = NOTE_INSN_DELETED; | |
2683 | NOTE_SOURCE_FILE (p) = 0; | |
2684 | } | |
2685 | } | |
2686 | goto flushed; | |
2687 | } | |
2688 | ||
916b1701 MM |
2689 | CLEAR_REG_SET (dead); |
2690 | CLEAR_REG_SET (live); | |
d7429b6a RK |
2691 | |
2692 | /* See if this is an increment or decrement that can be | |
2693 | merged into a following memory address. */ | |
2694 | #ifdef AUTO_INC_DEC | |
2695 | { | |
956d6950 JL |
2696 | register rtx x = single_set (insn); |
2697 | ||
d7429b6a | 2698 | /* Does this instruction increment or decrement a register? */ |
6764d250 BS |
2699 | if (!reload_completed |
2700 | && final && x != 0 | |
d7429b6a RK |
2701 | && GET_CODE (SET_DEST (x)) == REG |
2702 | && (GET_CODE (SET_SRC (x)) == PLUS | |
2703 | || GET_CODE (SET_SRC (x)) == MINUS) | |
2704 | && XEXP (SET_SRC (x), 0) == SET_DEST (x) | |
2705 | && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT | |
2706 | /* Ok, look for a following memory ref we can combine with. | |
2707 | If one is found, change the memory ref to a PRE_INC | |
2708 | or PRE_DEC, cancel this insn, and return 1. | |
2709 | Return 0 if nothing has been done. */ | |
2710 | && try_pre_increment_1 (insn)) | |
2711 | goto flushed; | |
2712 | } | |
2713 | #endif /* AUTO_INC_DEC */ | |
2714 | ||
2715 | /* If this is not the final pass, and this insn is copying the | |
2716 | value of a library call and it's dead, don't scan the | |
2717 | insns that perform the library call, so that the call's | |
2718 | arguments are not marked live. */ | |
2719 | if (libcall_is_dead) | |
2720 | { | |
2721 | /* Mark the dest reg as `significant'. */ | |
5f4f0e22 | 2722 | mark_set_regs (old, dead, PATTERN (insn), NULL_RTX, significant); |
d7429b6a RK |
2723 | |
2724 | insn = XEXP (note, 0); | |
2725 | prev = PREV_INSN (insn); | |
2726 | } | |
2727 | else if (GET_CODE (PATTERN (insn)) == SET | |
2728 | && SET_DEST (PATTERN (insn)) == stack_pointer_rtx | |
2729 | && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS | |
2730 | && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx | |
2731 | && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT) | |
2732 | /* We have an insn to pop a constant amount off the stack. | |
2733 | (Such insns use PLUS regardless of the direction of the stack, | |
2734 | and any insn to adjust the stack by a constant is always a pop.) | |
2735 | These insns, if not dead stores, have no effect on life. */ | |
2736 | ; | |
2737 | else | |
2738 | { | |
f8dd7f98 BS |
2739 | /* Any regs live at the time of a call instruction |
2740 | must not go in a register clobbered by calls. | |
2741 | Find all regs now live and record this for them. */ | |
2742 | ||
2743 | if (GET_CODE (insn) == CALL_INSN && final) | |
2744 | EXECUTE_IF_SET_IN_REG_SET (old, 0, i, | |
2745 | { | |
2746 | REG_N_CALLS_CROSSED (i)++; | |
2747 | }); | |
2748 | ||
d7429b6a RK |
2749 | /* LIVE gets the regs used in INSN; |
2750 | DEAD gets those set by it. Dead insns don't make anything | |
2751 | live. */ | |
2752 | ||
5f4f0e22 CH |
2753 | mark_set_regs (old, dead, PATTERN (insn), |
2754 | final ? insn : NULL_RTX, significant); | |
d7429b6a RK |
2755 | |
2756 | /* If an insn doesn't use CC0, it becomes dead since we | |
2757 | assume that every insn clobbers it. So show it dead here; | |
2758 | mark_used_regs will set it live if it is referenced. */ | |
2759 | cc0_live = 0; | |
2760 | ||
2761 | if (! insn_is_dead) | |
2762 | mark_used_regs (old, live, PATTERN (insn), final, insn); | |
2763 | ||
2764 | /* Sometimes we may have inserted something before INSN (such as | |
2765 | a move) when we make an auto-inc. So ensure we will scan | |
2766 | those insns. */ | |
2767 | #ifdef AUTO_INC_DEC | |
2768 | prev = PREV_INSN (insn); | |
2769 | #endif | |
2770 | ||
2771 | if (! insn_is_dead && GET_CODE (insn) == CALL_INSN) | |
2772 | { | |
2773 | register int i; | |
2774 | ||
6b67ec08 RK |
2775 | rtx note; |
2776 | ||
2777 | for (note = CALL_INSN_FUNCTION_USAGE (insn); | |
2778 | note; | |
2779 | note = XEXP (note, 1)) | |
2780 | if (GET_CODE (XEXP (note, 0)) == USE) | |
2781 | mark_used_regs (old, live, SET_DEST (XEXP (note, 0)), | |
2782 | final, insn); | |
2783 | ||
d7429b6a | 2784 | /* Each call clobbers all call-clobbered regs that are not |
e4329280 | 2785 | global or fixed. Note that the function-value reg is a |
d7429b6a RK |
2786 | call-clobbered reg, and mark_set_regs has already had |
2787 | a chance to handle it. */ | |
2788 | ||
2789 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
e4329280 RK |
2790 | if (call_used_regs[i] && ! global_regs[i] |
2791 | && ! fixed_regs[i]) | |
916b1701 | 2792 | SET_REGNO_REG_SET (dead, i); |
d7429b6a RK |
2793 | |
2794 | /* The stack ptr is used (honorarily) by a CALL insn. */ | |
916b1701 | 2795 | SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM); |
d7429b6a RK |
2796 | |
2797 | /* Calls may also reference any of the global registers, | |
2798 | so they are made live. */ | |
d7429b6a RK |
2799 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2800 | if (global_regs[i]) | |
9b316aa2 | 2801 | mark_used_regs (old, live, |
38a448ca | 2802 | gen_rtx_REG (reg_raw_mode[i], i), |
9b316aa2 | 2803 | final, insn); |
d7429b6a RK |
2804 | |
2805 | /* Calls also clobber memory. */ | |
db3a887b | 2806 | mem_set_list = NULL_RTX; |
d7429b6a RK |
2807 | } |
2808 | ||
2809 | /* Update OLD for the registers used or set. */ | |
916b1701 MM |
2810 | AND_COMPL_REG_SET (old, dead); |
2811 | IOR_REG_SET (old, live); | |
d7429b6a | 2812 | |
d7429b6a RK |
2813 | } |
2814 | ||
f8dd7f98 BS |
2815 | /* On final pass, update counts of how many insns each reg is live |
2816 | at. */ | |
d7429b6a | 2817 | if (final) |
f8dd7f98 BS |
2818 | EXECUTE_IF_SET_IN_REG_SET (old, 0, i, |
2819 | { REG_LIVE_LENGTH (i)++; }); | |
d7429b6a RK |
2820 | } |
2821 | flushed: ; | |
2822 | if (insn == first) | |
2823 | break; | |
2824 | } | |
2825 | ||
67f0e213 RK |
2826 | FREE_REG_SET (dead); |
2827 | FREE_REG_SET (live); | |
d7429b6a RK |
2828 | } |
2829 | \f | |
2830 | /* Return 1 if X (the body of an insn, or part of it) is just dead stores | |
2831 | (SET expressions whose destinations are registers dead after the insn). | |
2832 | NEEDED is the regset that says which regs are alive after the insn. | |
2833 | ||
e398aa80 R |
2834 | Unless CALL_OK is non-zero, an insn is needed if it contains a CALL. |
2835 | ||
2836 | If X is the entire body of an insn, NOTES contains the reg notes | |
2837 | pertaining to the insn. */ | |
d7429b6a RK |
2838 | |
2839 | static int | |
e398aa80 | 2840 | insn_dead_p (x, needed, call_ok, notes) |
d7429b6a RK |
2841 | rtx x; |
2842 | regset needed; | |
2843 | int call_ok; | |
e398aa80 | 2844 | rtx notes ATTRIBUTE_UNUSED; |
d7429b6a | 2845 | { |
e5e809f4 JL |
2846 | enum rtx_code code = GET_CODE (x); |
2847 | ||
e398aa80 R |
2848 | #ifdef AUTO_INC_DEC |
2849 | /* If flow is invoked after reload, we must take existing AUTO_INC | |
2850 | expresions into account. */ | |
2851 | if (reload_completed) | |
2852 | { | |
2853 | for ( ; notes; notes = XEXP (notes, 1)) | |
2854 | { | |
2855 | if (REG_NOTE_KIND (notes) == REG_INC) | |
2856 | { | |
2857 | int regno = REGNO (XEXP (notes, 0)); | |
2858 | ||
2859 | /* Don't delete insns to set global regs. */ | |
2860 | if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) | |
2861 | || REGNO_REG_SET_P (needed, regno)) | |
2862 | return 0; | |
2863 | } | |
2864 | } | |
2865 | } | |
2866 | #endif | |
2867 | ||
d7429b6a RK |
2868 | /* If setting something that's a reg or part of one, |
2869 | see if that register's altered value will be live. */ | |
2870 | ||
2871 | if (code == SET) | |
2872 | { | |
e5e809f4 JL |
2873 | rtx r = SET_DEST (x); |
2874 | ||
d7429b6a RK |
2875 | /* A SET that is a subroutine call cannot be dead. */ |
2876 | if (! call_ok && GET_CODE (SET_SRC (x)) == CALL) | |
2877 | return 0; | |
2878 | ||
2879 | #ifdef HAVE_cc0 | |
2880 | if (GET_CODE (r) == CC0) | |
2881 | return ! cc0_live; | |
2882 | #endif | |
2883 | ||
db3a887b CB |
2884 | if (GET_CODE (r) == MEM && ! MEM_VOLATILE_P (r)) |
2885 | { | |
2886 | rtx temp; | |
2887 | /* Walk the set of memory locations we are currently tracking | |
2888 | and see if one is an identical match to this memory location. | |
2889 | If so, this memory write is dead (remember, we're walking | |
2890 | backwards from the end of the block to the start. */ | |
2891 | temp = mem_set_list; | |
2892 | while (temp) | |
2893 | { | |
2894 | if (rtx_equal_p (XEXP (temp, 0), r)) | |
2895 | return 1; | |
2896 | temp = XEXP (temp, 1); | |
2897 | } | |
2898 | } | |
d7429b6a | 2899 | |
e5e809f4 JL |
2900 | while (GET_CODE (r) == SUBREG || GET_CODE (r) == STRICT_LOW_PART |
2901 | || GET_CODE (r) == ZERO_EXTRACT) | |
d7429b6a RK |
2902 | r = SUBREG_REG (r); |
2903 | ||
2904 | if (GET_CODE (r) == REG) | |
2905 | { | |
e5e809f4 | 2906 | int regno = REGNO (r); |
d7429b6a | 2907 | |
d8c8b8e3 | 2908 | /* Don't delete insns to set global regs. */ |
d7429b6a RK |
2909 | if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) |
2910 | /* Make sure insns to set frame pointer aren't deleted. */ | |
2911 | || regno == FRAME_POINTER_REGNUM | |
73a187c1 DE |
2912 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
2913 | || regno == HARD_FRAME_POINTER_REGNUM | |
2914 | #endif | |
d7e4fe8b RS |
2915 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
2916 | /* Make sure insns to set arg pointer are never deleted | |
2917 | (if the arg pointer isn't fixed, there will be a USE for | |
0f41302f | 2918 | it, so we can treat it normally). */ |
d7e4fe8b RS |
2919 | || (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) |
2920 | #endif | |
916b1701 | 2921 | || REGNO_REG_SET_P (needed, regno)) |
d7429b6a RK |
2922 | return 0; |
2923 | ||
2924 | /* If this is a hard register, verify that subsequent words are | |
2925 | not needed. */ | |
2926 | if (regno < FIRST_PSEUDO_REGISTER) | |
2927 | { | |
2928 | int n = HARD_REGNO_NREGS (regno, GET_MODE (r)); | |
2929 | ||
2930 | while (--n > 0) | |
916b1701 | 2931 | if (REGNO_REG_SET_P (needed, regno+n)) |
d7429b6a RK |
2932 | return 0; |
2933 | } | |
2934 | ||
2935 | return 1; | |
2936 | } | |
2937 | } | |
e5e809f4 | 2938 | |
d7429b6a RK |
2939 | /* If performing several activities, |
2940 | insn is dead if each activity is individually dead. | |
2941 | Also, CLOBBERs and USEs can be ignored; a CLOBBER or USE | |
2942 | that's inside a PARALLEL doesn't make the insn worth keeping. */ | |
2943 | else if (code == PARALLEL) | |
2944 | { | |
e5e809f4 JL |
2945 | int i = XVECLEN (x, 0); |
2946 | ||
d7429b6a | 2947 | for (i--; i >= 0; i--) |
e5e809f4 JL |
2948 | if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER |
2949 | && GET_CODE (XVECEXP (x, 0, i)) != USE | |
e398aa80 | 2950 | && ! insn_dead_p (XVECEXP (x, 0, i), needed, call_ok, NULL_RTX)) |
e5e809f4 JL |
2951 | return 0; |
2952 | ||
d7429b6a RK |
2953 | return 1; |
2954 | } | |
e5e809f4 JL |
2955 | |
2956 | /* A CLOBBER of a pseudo-register that is dead serves no purpose. That | |
2957 | is not necessarily true for hard registers. */ | |
2958 | else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG | |
2959 | && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER | |
2960 | && ! REGNO_REG_SET_P (needed, REGNO (XEXP (x, 0)))) | |
2961 | return 1; | |
2962 | ||
2963 | /* We do not check other CLOBBER or USE here. An insn consisting of just | |
2964 | a CLOBBER or just a USE should not be deleted. */ | |
d7429b6a RK |
2965 | return 0; |
2966 | } | |
2967 | ||
2968 | /* If X is the pattern of the last insn in a libcall, and assuming X is dead, | |
2969 | return 1 if the entire library call is dead. | |
2970 | This is true if X copies a register (hard or pseudo) | |
2971 | and if the hard return reg of the call insn is dead. | |
2972 | (The caller should have tested the destination of X already for death.) | |
2973 | ||
2974 | If this insn doesn't just copy a register, then we don't | |
2975 | have an ordinary libcall. In that case, cse could not have | |
2976 | managed to substitute the source for the dest later on, | |
2977 | so we can assume the libcall is dead. | |
2978 | ||
2979 | NEEDED is the bit vector of pseudoregs live before this insn. | |
2980 | NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */ | |
2981 | ||
2982 | static int | |
2983 | libcall_dead_p (x, needed, note, insn) | |
2984 | rtx x; | |
2985 | regset needed; | |
2986 | rtx note; | |
2987 | rtx insn; | |
2988 | { | |
2989 | register RTX_CODE code = GET_CODE (x); | |
2990 | ||
2991 | if (code == SET) | |
2992 | { | |
2993 | register rtx r = SET_SRC (x); | |
2994 | if (GET_CODE (r) == REG) | |
2995 | { | |
2996 | rtx call = XEXP (note, 0); | |
e398aa80 | 2997 | rtx call_pat; |
d7429b6a RK |
2998 | register int i; |
2999 | ||
3000 | /* Find the call insn. */ | |
3001 | while (call != insn && GET_CODE (call) != CALL_INSN) | |
3002 | call = NEXT_INSN (call); | |
3003 | ||
3004 | /* If there is none, do nothing special, | |
3005 | since ordinary death handling can understand these insns. */ | |
3006 | if (call == insn) | |
3007 | return 0; | |
3008 | ||
3009 | /* See if the hard reg holding the value is dead. | |
3010 | If this is a PARALLEL, find the call within it. */ | |
e398aa80 R |
3011 | call_pat = PATTERN (call); |
3012 | if (GET_CODE (call_pat) == PARALLEL) | |
d7429b6a | 3013 | { |
e398aa80 R |
3014 | for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--) |
3015 | if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET | |
3016 | && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL) | |
d7429b6a RK |
3017 | break; |
3018 | ||
761a5bcd JW |
3019 | /* This may be a library call that is returning a value |
3020 | via invisible pointer. Do nothing special, since | |
3021 | ordinary death handling can understand these insns. */ | |
d7429b6a | 3022 | if (i < 0) |
761a5bcd | 3023 | return 0; |
d7429b6a | 3024 | |
e398aa80 | 3025 | call_pat = XVECEXP (call_pat, 0, i); |
d7429b6a RK |
3026 | } |
3027 | ||
e398aa80 | 3028 | return insn_dead_p (call_pat, needed, 1, REG_NOTES (call)); |
d7429b6a RK |
3029 | } |
3030 | } | |
3031 | return 1; | |
3032 | } | |
3033 | ||
bd80fbde RH |
3034 | /* Return 1 if register REGNO was used before it was set, i.e. if it is |
3035 | live at function entry. Don't count global register variables, variables | |
3036 | in registers that can be used for function arg passing, or variables in | |
3037 | fixed hard registers. */ | |
d7429b6a RK |
3038 | |
3039 | int | |
3040 | regno_uninitialized (regno) | |
3041 | int regno; | |
3042 | { | |
b0b7b46a | 3043 | if (n_basic_blocks == 0 |
6a45254e | 3044 | || (regno < FIRST_PSEUDO_REGISTER |
bd80fbde RH |
3045 | && (global_regs[regno] |
3046 | || fixed_regs[regno] | |
3047 | || FUNCTION_ARG_REGNO_P (regno)))) | |
d7429b6a RK |
3048 | return 0; |
3049 | ||
e881bb1b | 3050 | return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno); |
d7429b6a RK |
3051 | } |
3052 | ||
3053 | /* 1 if register REGNO was alive at a place where `setjmp' was called | |
3054 | and was set more than once or is an argument. | |
3055 | Such regs may be clobbered by `longjmp'. */ | |
3056 | ||
3057 | int | |
3058 | regno_clobbered_at_setjmp (regno) | |
3059 | int regno; | |
3060 | { | |
3061 | if (n_basic_blocks == 0) | |
3062 | return 0; | |
3063 | ||
b1f21e0a | 3064 | return ((REG_N_SETS (regno) > 1 |
e881bb1b | 3065 | || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno)) |
916b1701 | 3066 | && REGNO_REG_SET_P (regs_live_at_setjmp, regno)); |
d7429b6a RK |
3067 | } |
3068 | \f | |
15e088b2 JL |
3069 | /* INSN references memory, possibly using autoincrement addressing modes. |
3070 | Find any entries on the mem_set_list that need to be invalidated due | |
3071 | to an address change. */ | |
3072 | static void | |
3073 | invalidate_mems_from_autoinc (insn) | |
3074 | rtx insn; | |
3075 | { | |
3076 | rtx note = REG_NOTES (insn); | |
3077 | for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) | |
3078 | { | |
3079 | if (REG_NOTE_KIND (note) == REG_INC) | |
3080 | { | |
3081 | rtx temp = mem_set_list; | |
3082 | rtx prev = NULL_RTX; | |
3083 | ||
3084 | while (temp) | |
3085 | { | |
3086 | if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0))) | |
3087 | { | |
3088 | /* Splice temp out of list. */ | |
3089 | if (prev) | |
3090 | XEXP (prev, 1) = XEXP (temp, 1); | |
3091 | else | |
3092 | mem_set_list = XEXP (temp, 1); | |
3093 | } | |
3094 | else | |
3095 | prev = temp; | |
3096 | temp = XEXP (temp, 1); | |
3097 | } | |
3098 | } | |
3099 | } | |
3100 | } | |
3101 | ||
d7429b6a RK |
3102 | /* Process the registers that are set within X. |
3103 | Their bits are set to 1 in the regset DEAD, | |
3104 | because they are dead prior to this insn. | |
3105 | ||
3106 | If INSN is nonzero, it is the insn being processed | |
3107 | and the fact that it is nonzero implies this is the FINAL pass | |
3108 | in propagate_block. In this case, various info about register | |
3109 | usage is stored, LOG_LINKS fields of insns are set up. */ | |
3110 | ||
d7429b6a RK |
3111 | static void |
3112 | mark_set_regs (needed, dead, x, insn, significant) | |
3113 | regset needed; | |
3114 | regset dead; | |
3115 | rtx x; | |
3116 | rtx insn; | |
3117 | regset significant; | |
3118 | { | |
3119 | register RTX_CODE code = GET_CODE (x); | |
3120 | ||
3121 | if (code == SET || code == CLOBBER) | |
3122 | mark_set_1 (needed, dead, x, insn, significant); | |
3123 | else if (code == PARALLEL) | |
3124 | { | |
3125 | register int i; | |
3126 | for (i = XVECLEN (x, 0) - 1; i >= 0; i--) | |
3127 | { | |
3128 | code = GET_CODE (XVECEXP (x, 0, i)); | |
3129 | if (code == SET || code == CLOBBER) | |
3130 | mark_set_1 (needed, dead, XVECEXP (x, 0, i), insn, significant); | |
3131 | } | |
3132 | } | |
3133 | } | |
3134 | ||
3135 | /* Process a single SET rtx, X. */ | |
3136 | ||
3137 | static void | |
3138 | mark_set_1 (needed, dead, x, insn, significant) | |
3139 | regset needed; | |
3140 | regset dead; | |
3141 | rtx x; | |
3142 | rtx insn; | |
3143 | regset significant; | |
3144 | { | |
3145 | register int regno; | |
3146 | register rtx reg = SET_DEST (x); | |
3147 | ||
86465af7 DM |
3148 | /* Some targets place small structures in registers for |
3149 | return values of functions. We have to detect this | |
3150 | case specially here to get correct flow information. */ | |
3151 | if (GET_CODE (reg) == PARALLEL | |
3152 | && GET_MODE (reg) == BLKmode) | |
3153 | { | |
3154 | register int i; | |
3155 | ||
3156 | for (i = XVECLEN (reg, 0) - 1; i >= 0; i--) | |
3157 | mark_set_1 (needed, dead, XVECEXP (reg, 0, i), insn, significant); | |
3158 | return; | |
3159 | } | |
3160 | ||
d7429b6a RK |
3161 | /* Modifying just one hardware register of a multi-reg value |
3162 | or just a byte field of a register | |
3163 | does not mean the value from before this insn is now dead. | |
3164 | But it does mean liveness of that register at the end of the block | |
3165 | is significant. | |
3166 | ||
3167 | Within mark_set_1, however, we treat it as if the register is | |
3168 | indeed modified. mark_used_regs will, however, also treat this | |
3169 | register as being used. Thus, we treat these insns as setting a | |
3170 | new value for the register as a function of its old value. This | |
3171 | cases LOG_LINKS to be made appropriately and this will help combine. */ | |
3172 | ||
3173 | while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT | |
3174 | || GET_CODE (reg) == SIGN_EXTRACT | |
3175 | || GET_CODE (reg) == STRICT_LOW_PART) | |
3176 | reg = XEXP (reg, 0); | |
3177 | ||
db3a887b CB |
3178 | /* If this set is a MEM, then it kills any aliased writes. |
3179 | If this set is a REG, then it kills any MEMs which use the reg. */ | |
d7429b6a | 3180 | if (GET_CODE (reg) == MEM |
db3a887b CB |
3181 | || GET_CODE (reg) == REG) |
3182 | { | |
3183 | rtx temp = mem_set_list; | |
3184 | rtx prev = NULL_RTX; | |
3185 | ||
3186 | while (temp) | |
3187 | { | |
3188 | if ((GET_CODE (reg) == MEM | |
3189 | && output_dependence (XEXP (temp, 0), reg)) | |
3190 | || (GET_CODE (reg) == REG | |
3191 | && reg_overlap_mentioned_p (reg, XEXP (temp, 0)))) | |
3192 | { | |
3193 | /* Splice this entry out of the list. */ | |
3194 | if (prev) | |
3195 | XEXP (prev, 1) = XEXP (temp, 1); | |
3196 | else | |
3197 | mem_set_list = XEXP (temp, 1); | |
3198 | } | |
3199 | else | |
3200 | prev = temp; | |
3201 | temp = XEXP (temp, 1); | |
3202 | } | |
3203 | } | |
15e088b2 JL |
3204 | |
3205 | /* If the memory reference had embedded side effects (autoincrement | |
3206 | address modes. Then we may need to kill some entries on the | |
3207 | memory set list. */ | |
3208 | if (insn && GET_CODE (reg) == MEM) | |
3209 | invalidate_mems_from_autoinc (insn); | |
3210 | ||
d7429b6a RK |
3211 | if (GET_CODE (reg) == MEM && ! side_effects_p (reg) |
3212 | /* There are no REG_INC notes for SP, so we can't assume we'll see | |
3213 | everything that invalidates it. To be safe, don't eliminate any | |
3214 | stores though SP; none of them should be redundant anyway. */ | |
3215 | && ! reg_mentioned_p (stack_pointer_rtx, reg)) | |
db3a887b | 3216 | mem_set_list = gen_rtx_EXPR_LIST (VOIDmode, reg, mem_set_list); |
d7429b6a RK |
3217 | |
3218 | if (GET_CODE (reg) == REG | |
3219 | && (regno = REGNO (reg), regno != FRAME_POINTER_REGNUM) | |
73a187c1 DE |
3220 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
3221 | && regno != HARD_FRAME_POINTER_REGNUM | |
3222 | #endif | |
d7e4fe8b RS |
3223 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
3224 | && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) | |
3225 | #endif | |
d7429b6a RK |
3226 | && ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])) |
3227 | /* && regno != STACK_POINTER_REGNUM) -- let's try without this. */ | |
3228 | { | |
916b1701 MM |
3229 | int some_needed = REGNO_REG_SET_P (needed, regno); |
3230 | int some_not_needed = ! some_needed; | |
d7429b6a RK |
3231 | |
3232 | /* Mark it as a significant register for this basic block. */ | |
3233 | if (significant) | |
916b1701 | 3234 | SET_REGNO_REG_SET (significant, regno); |
d7429b6a | 3235 | |
38e01259 | 3236 | /* Mark it as dead before this insn. */ |
916b1701 | 3237 | SET_REGNO_REG_SET (dead, regno); |
d7429b6a RK |
3238 | |
3239 | /* A hard reg in a wide mode may really be multiple registers. | |
3240 | If so, mark all of them just like the first. */ | |
3241 | if (regno < FIRST_PSEUDO_REGISTER) | |
3242 | { | |
3243 | int n; | |
3244 | ||
3245 | /* Nothing below is needed for the stack pointer; get out asap. | |
3246 | Eg, log links aren't needed, since combine won't use them. */ | |
3247 | if (regno == STACK_POINTER_REGNUM) | |
3248 | return; | |
3249 | ||
3250 | n = HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
3251 | while (--n > 0) | |
3252 | { | |
916b1701 MM |
3253 | int regno_n = regno + n; |
3254 | int needed_regno = REGNO_REG_SET_P (needed, regno_n); | |
d7429b6a | 3255 | if (significant) |
916b1701 | 3256 | SET_REGNO_REG_SET (significant, regno_n); |
cb9e8ad1 | 3257 | |
916b1701 MM |
3258 | SET_REGNO_REG_SET (dead, regno_n); |
3259 | some_needed |= needed_regno; | |
3260 | some_not_needed |= ! needed_regno; | |
d7429b6a RK |
3261 | } |
3262 | } | |
3263 | /* Additional data to record if this is the final pass. */ | |
3264 | if (insn) | |
3265 | { | |
3266 | register rtx y = reg_next_use[regno]; | |
3267 | register int blocknum = BLOCK_NUM (insn); | |
3268 | ||
3269 | /* If this is a hard reg, record this function uses the reg. */ | |
3270 | ||
3271 | if (regno < FIRST_PSEUDO_REGISTER) | |
3272 | { | |
3273 | register int i; | |
3274 | int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); | |
3275 | ||
3276 | for (i = regno; i < endregno; i++) | |
3277 | { | |
93514916 JW |
3278 | /* The next use is no longer "next", since a store |
3279 | intervenes. */ | |
3280 | reg_next_use[i] = 0; | |
3281 | ||
d7429b6a | 3282 | regs_ever_live[i] = 1; |
b1f21e0a | 3283 | REG_N_SETS (i)++; |
d7429b6a RK |
3284 | } |
3285 | } | |
3286 | else | |
3287 | { | |
93514916 JW |
3288 | /* The next use is no longer "next", since a store |
3289 | intervenes. */ | |
3290 | reg_next_use[regno] = 0; | |
3291 | ||
d7429b6a RK |
3292 | /* Keep track of which basic blocks each reg appears in. */ |
3293 | ||
b1f21e0a MM |
3294 | if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN) |
3295 | REG_BASIC_BLOCK (regno) = blocknum; | |
3296 | else if (REG_BASIC_BLOCK (regno) != blocknum) | |
3297 | REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL; | |
d7429b6a RK |
3298 | |
3299 | /* Count (weighted) references, stores, etc. This counts a | |
3300 | register twice if it is modified, but that is correct. */ | |
b1f21e0a | 3301 | REG_N_SETS (regno)++; |
d7429b6a | 3302 | |
b1f21e0a | 3303 | REG_N_REFS (regno) += loop_depth; |
d7429b6a RK |
3304 | |
3305 | /* The insns where a reg is live are normally counted | |
3306 | elsewhere, but we want the count to include the insn | |
3307 | where the reg is set, and the normal counting mechanism | |
3308 | would not count it. */ | |
b1f21e0a | 3309 | REG_LIVE_LENGTH (regno)++; |
d7429b6a RK |
3310 | } |
3311 | ||
cb9e8ad1 | 3312 | if (! some_not_needed) |
d7429b6a RK |
3313 | { |
3314 | /* Make a logical link from the next following insn | |
3315 | that uses this register, back to this insn. | |
3316 | The following insns have already been processed. | |
3317 | ||
3318 | We don't build a LOG_LINK for hard registers containing | |
3319 | in ASM_OPERANDs. If these registers get replaced, | |
3320 | we might wind up changing the semantics of the insn, | |
3321 | even if reload can make what appear to be valid assignments | |
3322 | later. */ | |
3323 | if (y && (BLOCK_NUM (y) == blocknum) | |
3324 | && (regno >= FIRST_PSEUDO_REGISTER | |
3325 | || asm_noperands (PATTERN (y)) < 0)) | |
3326 | LOG_LINKS (y) | |
38a448ca | 3327 | = gen_rtx_INSN_LIST (VOIDmode, insn, LOG_LINKS (y)); |
d7429b6a RK |
3328 | } |
3329 | else if (! some_needed) | |
3330 | { | |
3331 | /* Note that dead stores have already been deleted when possible | |
3332 | If we get here, we have found a dead store that cannot | |
3333 | be eliminated (because the same insn does something useful). | |
3334 | Indicate this by marking the reg being set as dying here. */ | |
3335 | REG_NOTES (insn) | |
38a448ca | 3336 | = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn)); |
b1f21e0a | 3337 | REG_N_DEATHS (REGNO (reg))++; |
d7429b6a RK |
3338 | } |
3339 | else | |
3340 | { | |
3341 | /* This is a case where we have a multi-word hard register | |
3342 | and some, but not all, of the words of the register are | |
3343 | needed in subsequent insns. Write REG_UNUSED notes | |
3344 | for those parts that were not needed. This case should | |
3345 | be rare. */ | |
3346 | ||
3347 | int i; | |
3348 | ||
3349 | for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1; | |
3350 | i >= 0; i--) | |
916b1701 | 3351 | if (!REGNO_REG_SET_P (needed, regno + i)) |
d7429b6a | 3352 | REG_NOTES (insn) |
38a448ca RH |
3353 | = gen_rtx_EXPR_LIST (REG_UNUSED, |
3354 | gen_rtx_REG (reg_raw_mode[regno + i], | |
3355 | regno + i), | |
3356 | REG_NOTES (insn)); | |
d7429b6a RK |
3357 | } |
3358 | } | |
3359 | } | |
8244fc4f RS |
3360 | else if (GET_CODE (reg) == REG) |
3361 | reg_next_use[regno] = 0; | |
d7429b6a RK |
3362 | |
3363 | /* If this is the last pass and this is a SCRATCH, show it will be dying | |
3364 | here and count it. */ | |
3365 | else if (GET_CODE (reg) == SCRATCH && insn != 0) | |
3366 | { | |
3367 | REG_NOTES (insn) | |
38a448ca | 3368 | = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn)); |
d7429b6a RK |
3369 | } |
3370 | } | |
3371 | \f | |
3372 | #ifdef AUTO_INC_DEC | |
3373 | ||
3374 | /* X is a MEM found in INSN. See if we can convert it into an auto-increment | |
3375 | reference. */ | |
3376 | ||
3377 | static void | |
3378 | find_auto_inc (needed, x, insn) | |
3379 | regset needed; | |
3380 | rtx x; | |
3381 | rtx insn; | |
3382 | { | |
3383 | rtx addr = XEXP (x, 0); | |
e658434c | 3384 | HOST_WIDE_INT offset = 0; |
05ed5d57 | 3385 | rtx set; |
d7429b6a RK |
3386 | |
3387 | /* Here we detect use of an index register which might be good for | |
3388 | postincrement, postdecrement, preincrement, or predecrement. */ | |
3389 | ||
3390 | if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT) | |
3391 | offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0); | |
3392 | ||
3393 | if (GET_CODE (addr) == REG) | |
3394 | { | |
3395 | register rtx y; | |
3396 | register int size = GET_MODE_SIZE (GET_MODE (x)); | |
3397 | rtx use; | |
3398 | rtx incr; | |
3399 | int regno = REGNO (addr); | |
3400 | ||
3401 | /* Is the next use an increment that might make auto-increment? */ | |
05ed5d57 RK |
3402 | if ((incr = reg_next_use[regno]) != 0 |
3403 | && (set = single_set (incr)) != 0 | |
3404 | && GET_CODE (set) == SET | |
d7429b6a RK |
3405 | && BLOCK_NUM (incr) == BLOCK_NUM (insn) |
3406 | /* Can't add side effects to jumps; if reg is spilled and | |
3407 | reloaded, there's no way to store back the altered value. */ | |
3408 | && GET_CODE (insn) != JUMP_INSN | |
05ed5d57 | 3409 | && (y = SET_SRC (set), GET_CODE (y) == PLUS) |
d7429b6a RK |
3410 | && XEXP (y, 0) == addr |
3411 | && GET_CODE (XEXP (y, 1)) == CONST_INT | |
940da324 JL |
3412 | && ((HAVE_POST_INCREMENT |
3413 | && (INTVAL (XEXP (y, 1)) == size && offset == 0)) | |
3414 | || (HAVE_POST_DECREMENT | |
3415 | && (INTVAL (XEXP (y, 1)) == - size && offset == 0)) | |
3416 | || (HAVE_PRE_INCREMENT | |
3417 | && (INTVAL (XEXP (y, 1)) == size && offset == size)) | |
3418 | || (HAVE_PRE_DECREMENT | |
3419 | && (INTVAL (XEXP (y, 1)) == - size && offset == - size))) | |
d7429b6a RK |
3420 | /* Make sure this reg appears only once in this insn. */ |
3421 | && (use = find_use_as_address (PATTERN (insn), addr, offset), | |
3422 | use != 0 && use != (rtx) 1)) | |
3423 | { | |
05ed5d57 | 3424 | rtx q = SET_DEST (set); |
7280c2a4 RK |
3425 | enum rtx_code inc_code = (INTVAL (XEXP (y, 1)) == size |
3426 | ? (offset ? PRE_INC : POST_INC) | |
3427 | : (offset ? PRE_DEC : POST_DEC)); | |
d7429b6a RK |
3428 | |
3429 | if (dead_or_set_p (incr, addr)) | |
7280c2a4 RK |
3430 | { |
3431 | /* This is the simple case. Try to make the auto-inc. If | |
3432 | we can't, we are done. Otherwise, we will do any | |
3433 | needed updates below. */ | |
3434 | if (! validate_change (insn, &XEXP (x, 0), | |
38a448ca | 3435 | gen_rtx_fmt_e (inc_code, Pmode, addr), |
7280c2a4 RK |
3436 | 0)) |
3437 | return; | |
3438 | } | |
5175ad37 DE |
3439 | else if (GET_CODE (q) == REG |
3440 | /* PREV_INSN used here to check the semi-open interval | |
3441 | [insn,incr). */ | |
b24884cd JL |
3442 | && ! reg_used_between_p (q, PREV_INSN (insn), incr) |
3443 | /* We must also check for sets of q as q may be | |
3444 | a call clobbered hard register and there may | |
3445 | be a call between PREV_INSN (insn) and incr. */ | |
3446 | && ! reg_set_between_p (q, PREV_INSN (insn), incr)) | |
d7429b6a | 3447 | { |
5175ad37 | 3448 | /* We have *p followed sometime later by q = p+size. |
d7429b6a | 3449 | Both p and q must be live afterward, |
9ec36da5 | 3450 | and q is not used between INSN and its assignment. |
d7429b6a RK |
3451 | Change it to q = p, ...*q..., q = q+size. |
3452 | Then fall into the usual case. */ | |
3453 | rtx insns, temp; | |
e881bb1b | 3454 | basic_block bb; |
d7429b6a RK |
3455 | |
3456 | start_sequence (); | |
3457 | emit_move_insn (q, addr); | |
3458 | insns = get_insns (); | |
3459 | end_sequence (); | |
3460 | ||
e881bb1b | 3461 | bb = BLOCK_FOR_INSN (insn); |
d7429b6a | 3462 | for (temp = insns; temp; temp = NEXT_INSN (temp)) |
e881bb1b | 3463 | set_block_for_insn (temp, bb); |
d7429b6a | 3464 | |
7280c2a4 RK |
3465 | /* If we can't make the auto-inc, or can't make the |
3466 | replacement into Y, exit. There's no point in making | |
3467 | the change below if we can't do the auto-inc and doing | |
3468 | so is not correct in the pre-inc case. */ | |
3469 | ||
3470 | validate_change (insn, &XEXP (x, 0), | |
38a448ca | 3471 | gen_rtx_fmt_e (inc_code, Pmode, q), |
7280c2a4 RK |
3472 | 1); |
3473 | validate_change (incr, &XEXP (y, 0), q, 1); | |
3474 | if (! apply_change_group ()) | |
3475 | return; | |
3476 | ||
3477 | /* We now know we'll be doing this change, so emit the | |
3478 | new insn(s) and do the updates. */ | |
d7429b6a | 3479 | emit_insns_before (insns, insn); |
e8b641a1 | 3480 | |
e881bb1b RH |
3481 | if (BLOCK_FOR_INSN (insn)->head == insn) |
3482 | BLOCK_FOR_INSN (insn)->head = insns; | |
e8b641a1 | 3483 | |
d7429b6a RK |
3484 | /* INCR will become a NOTE and INSN won't contain a |
3485 | use of ADDR. If a use of ADDR was just placed in | |
3486 | the insn before INSN, make that the next use. | |
3487 | Otherwise, invalidate it. */ | |
3488 | if (GET_CODE (PREV_INSN (insn)) == INSN | |
3489 | && GET_CODE (PATTERN (PREV_INSN (insn))) == SET | |
3490 | && SET_SRC (PATTERN (PREV_INSN (insn))) == addr) | |
3491 | reg_next_use[regno] = PREV_INSN (insn); | |
3492 | else | |
3493 | reg_next_use[regno] = 0; | |
3494 | ||
3495 | addr = q; | |
3496 | regno = REGNO (q); | |
d7429b6a RK |
3497 | |
3498 | /* REGNO is now used in INCR which is below INSN, but | |
3499 | it previously wasn't live here. If we don't mark | |
3500 | it as needed, we'll put a REG_DEAD note for it | |
3501 | on this insn, which is incorrect. */ | |
916b1701 | 3502 | SET_REGNO_REG_SET (needed, regno); |
d7429b6a RK |
3503 | |
3504 | /* If there are any calls between INSN and INCR, show | |
3505 | that REGNO now crosses them. */ | |
3506 | for (temp = insn; temp != incr; temp = NEXT_INSN (temp)) | |
3507 | if (GET_CODE (temp) == CALL_INSN) | |
b1f21e0a | 3508 | REG_N_CALLS_CROSSED (regno)++; |
d7429b6a | 3509 | } |
02df8aba RK |
3510 | else |
3511 | return; | |
d7429b6a | 3512 | |
7280c2a4 RK |
3513 | /* If we haven't returned, it means we were able to make the |
3514 | auto-inc, so update the status. First, record that this insn | |
3515 | has an implicit side effect. */ | |
3516 | ||
3517 | REG_NOTES (insn) | |
38a448ca | 3518 | = gen_rtx_EXPR_LIST (REG_INC, addr, REG_NOTES (insn)); |
7280c2a4 RK |
3519 | |
3520 | /* Modify the old increment-insn to simply copy | |
3521 | the already-incremented value of our register. */ | |
3522 | if (! validate_change (incr, &SET_SRC (set), addr, 0)) | |
3523 | abort (); | |
3524 | ||
3525 | /* If that makes it a no-op (copying the register into itself) delete | |
3526 | it so it won't appear to be a "use" and a "set" of this | |
3527 | register. */ | |
3528 | if (SET_DEST (set) == addr) | |
d7429b6a | 3529 | { |
7280c2a4 RK |
3530 | PUT_CODE (incr, NOTE); |
3531 | NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED; | |
3532 | NOTE_SOURCE_FILE (incr) = 0; | |
3533 | } | |
d7429b6a | 3534 | |
7280c2a4 RK |
3535 | if (regno >= FIRST_PSEUDO_REGISTER) |
3536 | { | |
3537 | /* Count an extra reference to the reg. When a reg is | |
3538 | incremented, spilling it is worse, so we want to make | |
3539 | that less likely. */ | |
b1f21e0a | 3540 | REG_N_REFS (regno) += loop_depth; |
7280c2a4 RK |
3541 | |
3542 | /* Count the increment as a setting of the register, | |
3543 | even though it isn't a SET in rtl. */ | |
b1f21e0a | 3544 | REG_N_SETS (regno)++; |
d7429b6a RK |
3545 | } |
3546 | } | |
3547 | } | |
3548 | } | |
3549 | #endif /* AUTO_INC_DEC */ | |
3550 | \f | |
3551 | /* Scan expression X and store a 1-bit in LIVE for each reg it uses. | |
3552 | This is done assuming the registers needed from X | |
3553 | are those that have 1-bits in NEEDED. | |
3554 | ||
3555 | On the final pass, FINAL is 1. This means try for autoincrement | |
3556 | and count the uses and deaths of each pseudo-reg. | |
3557 | ||
3558 | INSN is the containing instruction. If INSN is dead, this function is not | |
3559 | called. */ | |
3560 | ||
3561 | static void | |
3562 | mark_used_regs (needed, live, x, final, insn) | |
3563 | regset needed; | |
3564 | regset live; | |
3565 | rtx x; | |
d7429b6a | 3566 | int final; |
e658434c | 3567 | rtx insn; |
d7429b6a RK |
3568 | { |
3569 | register RTX_CODE code; | |
3570 | register int regno; | |
3571 | int i; | |
3572 | ||
3573 | retry: | |
3574 | code = GET_CODE (x); | |
3575 | switch (code) | |
3576 | { | |
3577 | case LABEL_REF: | |
3578 | case SYMBOL_REF: | |
3579 | case CONST_INT: | |
3580 | case CONST: | |
3581 | case CONST_DOUBLE: | |
3582 | case PC: | |
d7429b6a RK |
3583 | case ADDR_VEC: |
3584 | case ADDR_DIFF_VEC: | |
3585 | case ASM_INPUT: | |
3586 | return; | |
3587 | ||
3588 | #ifdef HAVE_cc0 | |
3589 | case CC0: | |
3590 | cc0_live = 1; | |
3591 | return; | |
3592 | #endif | |
3593 | ||
2f1553a4 RK |
3594 | case CLOBBER: |
3595 | /* If we are clobbering a MEM, mark any registers inside the address | |
3596 | as being used. */ | |
3597 | if (GET_CODE (XEXP (x, 0)) == MEM) | |
3598 | mark_used_regs (needed, live, XEXP (XEXP (x, 0), 0), final, insn); | |
3599 | return; | |
3600 | ||
d7429b6a | 3601 | case MEM: |
7eb136d6 MM |
3602 | /* Invalidate the data for the last MEM stored, but only if MEM is |
3603 | something that can be stored into. */ | |
3604 | if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF | |
3605 | && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0))) | |
db3a887b | 3606 | ; /* needn't clear the memory set list */ |
7eb136d6 | 3607 | else |
db3a887b CB |
3608 | { |
3609 | rtx temp = mem_set_list; | |
3610 | rtx prev = NULL_RTX; | |
3611 | ||
3612 | while (temp) | |
3613 | { | |
063cd522 | 3614 | if (anti_dependence (XEXP (temp, 0), x)) |
db3a887b CB |
3615 | { |
3616 | /* Splice temp out of the list. */ | |
3617 | if (prev) | |
3618 | XEXP (prev, 1) = XEXP (temp, 1); | |
3619 | else | |
3620 | mem_set_list = XEXP (temp, 1); | |
3621 | } | |
3622 | else | |
3623 | prev = temp; | |
3624 | temp = XEXP (temp, 1); | |
3625 | } | |
3626 | } | |
d7429b6a | 3627 | |
15e088b2 JL |
3628 | /* If the memory reference had embedded side effects (autoincrement |
3629 | address modes. Then we may need to kill some entries on the | |
3630 | memory set list. */ | |
3631 | if (insn) | |
3632 | invalidate_mems_from_autoinc (insn); | |
3633 | ||
d7429b6a RK |
3634 | #ifdef AUTO_INC_DEC |
3635 | if (final) | |
3636 | find_auto_inc (needed, x, insn); | |
3637 | #endif | |
3638 | break; | |
3639 | ||
80f8f04a RK |
3640 | case SUBREG: |
3641 | if (GET_CODE (SUBREG_REG (x)) == REG | |
3642 | && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER | |
3643 | && (GET_MODE_SIZE (GET_MODE (x)) | |
88285acf | 3644 | != GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))) |
b1f21e0a | 3645 | REG_CHANGES_SIZE (REGNO (SUBREG_REG (x))) = 1; |
80f8f04a RK |
3646 | |
3647 | /* While we're here, optimize this case. */ | |
3648 | x = SUBREG_REG (x); | |
3649 | ||
e100a3bb | 3650 | /* In case the SUBREG is not of a register, don't optimize */ |
ce79abf3 | 3651 | if (GET_CODE (x) != REG) |
e100a3bb MM |
3652 | { |
3653 | mark_used_regs (needed, live, x, final, insn); | |
3654 | return; | |
3655 | } | |
ce79abf3 | 3656 | |
0f41302f | 3657 | /* ... fall through ... */ |
80f8f04a | 3658 | |
d7429b6a RK |
3659 | case REG: |
3660 | /* See a register other than being set | |
3661 | => mark it as needed. */ | |
3662 | ||
3663 | regno = REGNO (x); | |
3664 | { | |
67f0e213 RK |
3665 | int some_needed = REGNO_REG_SET_P (needed, regno); |
3666 | int some_not_needed = ! some_needed; | |
d7429b6a | 3667 | |
916b1701 | 3668 | SET_REGNO_REG_SET (live, regno); |
cb9e8ad1 | 3669 | |
d7429b6a RK |
3670 | /* A hard reg in a wide mode may really be multiple registers. |
3671 | If so, mark all of them just like the first. */ | |
3672 | if (regno < FIRST_PSEUDO_REGISTER) | |
3673 | { | |
3674 | int n; | |
3675 | ||
d7e4fe8b | 3676 | /* For stack ptr or fixed arg pointer, |
d7429b6a RK |
3677 | nothing below can be necessary, so waste no more time. */ |
3678 | if (regno == STACK_POINTER_REGNUM | |
73a187c1 DE |
3679 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
3680 | || regno == HARD_FRAME_POINTER_REGNUM | |
3681 | #endif | |
d7e4fe8b RS |
3682 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
3683 | || (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) | |
3684 | #endif | |
d7429b6a RK |
3685 | || regno == FRAME_POINTER_REGNUM) |
3686 | { | |
3687 | /* If this is a register we are going to try to eliminate, | |
3688 | don't mark it live here. If we are successful in | |
3689 | eliminating it, it need not be live unless it is used for | |
3690 | pseudos, in which case it will have been set live when | |
3691 | it was allocated to the pseudos. If the register will not | |
3692 | be eliminated, reload will set it live at that point. */ | |
3693 | ||
3694 | if (! TEST_HARD_REG_BIT (elim_reg_set, regno)) | |
3695 | regs_ever_live[regno] = 1; | |
3696 | return; | |
3697 | } | |
3698 | /* No death notes for global register variables; | |
3699 | their values are live after this function exits. */ | |
3700 | if (global_regs[regno]) | |
d8c8b8e3 RS |
3701 | { |
3702 | if (final) | |
3703 | reg_next_use[regno] = insn; | |
3704 | return; | |
3705 | } | |
d7429b6a RK |
3706 | |
3707 | n = HARD_REGNO_NREGS (regno, GET_MODE (x)); | |
3708 | while (--n > 0) | |
3709 | { | |
916b1701 MM |
3710 | int regno_n = regno + n; |
3711 | int needed_regno = REGNO_REG_SET_P (needed, regno_n); | |
cb9e8ad1 | 3712 | |
916b1701 MM |
3713 | SET_REGNO_REG_SET (live, regno_n); |
3714 | some_needed |= needed_regno; | |
931c6c7a | 3715 | some_not_needed |= ! needed_regno; |
d7429b6a RK |
3716 | } |
3717 | } | |
3718 | if (final) | |
3719 | { | |
3720 | /* Record where each reg is used, so when the reg | |
3721 | is set we know the next insn that uses it. */ | |
3722 | ||
3723 | reg_next_use[regno] = insn; | |
3724 | ||
3725 | if (regno < FIRST_PSEUDO_REGISTER) | |
3726 | { | |
3727 | /* If a hard reg is being used, | |
3728 | record that this function does use it. */ | |
3729 | ||
3730 | i = HARD_REGNO_NREGS (regno, GET_MODE (x)); | |
3731 | if (i == 0) | |
3732 | i = 1; | |
3733 | do | |
3734 | regs_ever_live[regno + --i] = 1; | |
3735 | while (i > 0); | |
3736 | } | |
3737 | else | |
3738 | { | |
3739 | /* Keep track of which basic block each reg appears in. */ | |
3740 | ||
3741 | register int blocknum = BLOCK_NUM (insn); | |
3742 | ||
b1f21e0a MM |
3743 | if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN) |
3744 | REG_BASIC_BLOCK (regno) = blocknum; | |
3745 | else if (REG_BASIC_BLOCK (regno) != blocknum) | |
3746 | REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL; | |
d7429b6a RK |
3747 | |
3748 | /* Count (weighted) number of uses of each reg. */ | |
3749 | ||
b1f21e0a | 3750 | REG_N_REFS (regno) += loop_depth; |
d7429b6a RK |
3751 | } |
3752 | ||
3753 | /* Record and count the insns in which a reg dies. | |
3754 | If it is used in this insn and was dead below the insn | |
3755 | then it dies in this insn. If it was set in this insn, | |
3756 | we do not make a REG_DEAD note; likewise if we already | |
3757 | made such a note. */ | |
3758 | ||
cb9e8ad1 | 3759 | if (some_not_needed |
d7429b6a RK |
3760 | && ! dead_or_set_p (insn, x) |
3761 | #if 0 | |
3762 | && (regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
3763 | #endif | |
3764 | ) | |
3765 | { | |
ab28041e JW |
3766 | /* Check for the case where the register dying partially |
3767 | overlaps the register set by this insn. */ | |
3768 | if (regno < FIRST_PSEUDO_REGISTER | |
3769 | && HARD_REGNO_NREGS (regno, GET_MODE (x)) > 1) | |
3770 | { | |
480eac3b | 3771 | int n = HARD_REGNO_NREGS (regno, GET_MODE (x)); |
ab28041e JW |
3772 | while (--n >= 0) |
3773 | some_needed |= dead_or_set_regno_p (insn, regno + n); | |
3774 | } | |
3775 | ||
d7429b6a RK |
3776 | /* If none of the words in X is needed, make a REG_DEAD |
3777 | note. Otherwise, we must make partial REG_DEAD notes. */ | |
3778 | if (! some_needed) | |
3779 | { | |
3780 | REG_NOTES (insn) | |
38a448ca | 3781 | = gen_rtx_EXPR_LIST (REG_DEAD, x, REG_NOTES (insn)); |
b1f21e0a | 3782 | REG_N_DEATHS (regno)++; |
d7429b6a RK |
3783 | } |
3784 | else | |
3785 | { | |
3786 | int i; | |
3787 | ||
3788 | /* Don't make a REG_DEAD note for a part of a register | |
3789 | that is set in the insn. */ | |
3790 | ||
3791 | for (i = HARD_REGNO_NREGS (regno, GET_MODE (x)) - 1; | |
3792 | i >= 0; i--) | |
916b1701 | 3793 | if (!REGNO_REG_SET_P (needed, regno + i) |
d7429b6a RK |
3794 | && ! dead_or_set_regno_p (insn, regno + i)) |
3795 | REG_NOTES (insn) | |
38a448ca RH |
3796 | = gen_rtx_EXPR_LIST (REG_DEAD, |
3797 | gen_rtx_REG (reg_raw_mode[regno + i], | |
3798 | regno + i), | |
3799 | REG_NOTES (insn)); | |
d7429b6a RK |
3800 | } |
3801 | } | |
3802 | } | |
3803 | } | |
3804 | return; | |
3805 | ||
3806 | case SET: | |
3807 | { | |
3808 | register rtx testreg = SET_DEST (x); | |
3809 | int mark_dest = 0; | |
3810 | ||
3811 | /* If storing into MEM, don't show it as being used. But do | |
3812 | show the address as being used. */ | |
3813 | if (GET_CODE (testreg) == MEM) | |
3814 | { | |
3815 | #ifdef AUTO_INC_DEC | |
3816 | if (final) | |
3817 | find_auto_inc (needed, testreg, insn); | |
3818 | #endif | |
3819 | mark_used_regs (needed, live, XEXP (testreg, 0), final, insn); | |
3820 | mark_used_regs (needed, live, SET_SRC (x), final, insn); | |
3821 | return; | |
3822 | } | |
3823 | ||
3824 | /* Storing in STRICT_LOW_PART is like storing in a reg | |
3825 | in that this SET might be dead, so ignore it in TESTREG. | |
3826 | but in some other ways it is like using the reg. | |
3827 | ||
3828 | Storing in a SUBREG or a bit field is like storing the entire | |
3829 | register in that if the register's value is not used | |
3830 | then this SET is not needed. */ | |
3831 | while (GET_CODE (testreg) == STRICT_LOW_PART | |
3832 | || GET_CODE (testreg) == ZERO_EXTRACT | |
3833 | || GET_CODE (testreg) == SIGN_EXTRACT | |
3834 | || GET_CODE (testreg) == SUBREG) | |
3835 | { | |
88285acf RK |
3836 | if (GET_CODE (testreg) == SUBREG |
3837 | && GET_CODE (SUBREG_REG (testreg)) == REG | |
3838 | && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER | |
3839 | && (GET_MODE_SIZE (GET_MODE (testreg)) | |
3840 | != GET_MODE_SIZE (GET_MODE (SUBREG_REG (testreg))))) | |
b1f21e0a | 3841 | REG_CHANGES_SIZE (REGNO (SUBREG_REG (testreg))) = 1; |
88285acf | 3842 | |
d7429b6a RK |
3843 | /* Modifying a single register in an alternate mode |
3844 | does not use any of the old value. But these other | |
3845 | ways of storing in a register do use the old value. */ | |
3846 | if (GET_CODE (testreg) == SUBREG | |
3847 | && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg))) | |
3848 | ; | |
3849 | else | |
3850 | mark_dest = 1; | |
3851 | ||
3852 | testreg = XEXP (testreg, 0); | |
3853 | } | |
3854 | ||
3855 | /* If this is a store into a register, | |
3856 | recursively scan the value being stored. */ | |
3857 | ||
86465af7 DM |
3858 | if ((GET_CODE (testreg) == PARALLEL |
3859 | && GET_MODE (testreg) == BLKmode) | |
3860 | || (GET_CODE (testreg) == REG | |
3861 | && (regno = REGNO (testreg), regno != FRAME_POINTER_REGNUM) | |
73a187c1 | 3862 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
86465af7 | 3863 | && regno != HARD_FRAME_POINTER_REGNUM |
73a187c1 | 3864 | #endif |
d7e4fe8b | 3865 | #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM |
86465af7 | 3866 | && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) |
d7e4fe8b | 3867 | #endif |
86465af7 | 3868 | )) |
d8c8b8e3 RS |
3869 | /* We used to exclude global_regs here, but that seems wrong. |
3870 | Storing in them is like storing in mem. */ | |
d7429b6a RK |
3871 | { |
3872 | mark_used_regs (needed, live, SET_SRC (x), final, insn); | |
3873 | if (mark_dest) | |
3874 | mark_used_regs (needed, live, SET_DEST (x), final, insn); | |
3875 | return; | |
3876 | } | |
3877 | } | |
3878 | break; | |
3879 | ||
3880 | case RETURN: | |
3881 | /* If exiting needs the right stack value, consider this insn as | |
3882 | using the stack pointer. In any event, consider it as using | |
632c9d9e | 3883 | all global registers and all registers used by return. */ |
d7429b6a | 3884 | if (! EXIT_IGNORE_STACK |
0200b5ed JL |
3885 | || (! FRAME_POINTER_REQUIRED |
3886 | && ! current_function_calls_alloca | |
bfc5000a JL |
3887 | && flag_omit_frame_pointer) |
3888 | || current_function_sp_is_unchanging) | |
916b1701 | 3889 | SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM); |
d7429b6a RK |
3890 | |
3891 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
632c9d9e MS |
3892 | if (global_regs[i] |
3893 | #ifdef EPILOGUE_USES | |
3894 | || EPILOGUE_USES (i) | |
3895 | #endif | |
3896 | ) | |
916b1701 | 3897 | SET_REGNO_REG_SET (live, i); |
d7429b6a | 3898 | break; |
e9a25f70 JL |
3899 | |
3900 | default: | |
3901 | break; | |
d7429b6a RK |
3902 | } |
3903 | ||
3904 | /* Recursively scan the operands of this expression. */ | |
3905 | ||
3906 | { | |
3907 | register char *fmt = GET_RTX_FORMAT (code); | |
3908 | register int i; | |
3909 | ||
3910 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
3911 | { | |
3912 | if (fmt[i] == 'e') | |
3913 | { | |
3914 | /* Tail recursive case: save a function call level. */ | |
3915 | if (i == 0) | |
3916 | { | |
3917 | x = XEXP (x, 0); | |
3918 | goto retry; | |
3919 | } | |
3920 | mark_used_regs (needed, live, XEXP (x, i), final, insn); | |
3921 | } | |
3922 | else if (fmt[i] == 'E') | |
3923 | { | |
3924 | register int j; | |
3925 | for (j = 0; j < XVECLEN (x, i); j++) | |
3926 | mark_used_regs (needed, live, XVECEXP (x, i, j), final, insn); | |
3927 | } | |
3928 | } | |
3929 | } | |
3930 | } | |
3931 | \f | |
3932 | #ifdef AUTO_INC_DEC | |
3933 | ||
3934 | static int | |
3935 | try_pre_increment_1 (insn) | |
3936 | rtx insn; | |
3937 | { | |
3938 | /* Find the next use of this reg. If in same basic block, | |
3939 | make it do pre-increment or pre-decrement if appropriate. */ | |
956d6950 | 3940 | rtx x = single_set (insn); |
5f4f0e22 | 3941 | HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1) |
d7429b6a RK |
3942 | * INTVAL (XEXP (SET_SRC (x), 1))); |
3943 | int regno = REGNO (SET_DEST (x)); | |
3944 | rtx y = reg_next_use[regno]; | |
3945 | if (y != 0 | |
3946 | && BLOCK_NUM (y) == BLOCK_NUM (insn) | |
89861c38 | 3947 | /* Don't do this if the reg dies, or gets set in y; a standard addressing |
0f41302f | 3948 | mode would be better. */ |
89861c38 | 3949 | && ! dead_or_set_p (y, SET_DEST (x)) |
956d6950 | 3950 | && try_pre_increment (y, SET_DEST (x), amount)) |
d7429b6a RK |
3951 | { |
3952 | /* We have found a suitable auto-increment | |
3953 | and already changed insn Y to do it. | |
3954 | So flush this increment-instruction. */ | |
3955 | PUT_CODE (insn, NOTE); | |
3956 | NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; | |
3957 | NOTE_SOURCE_FILE (insn) = 0; | |
3958 | /* Count a reference to this reg for the increment | |
3959 | insn we are deleting. When a reg is incremented. | |
3960 | spilling it is worse, so we want to make that | |
3961 | less likely. */ | |
3962 | if (regno >= FIRST_PSEUDO_REGISTER) | |
3963 | { | |
b1f21e0a MM |
3964 | REG_N_REFS (regno) += loop_depth; |
3965 | REG_N_SETS (regno)++; | |
d7429b6a RK |
3966 | } |
3967 | return 1; | |
3968 | } | |
3969 | return 0; | |
3970 | } | |
3971 | ||
3972 | /* Try to change INSN so that it does pre-increment or pre-decrement | |
3973 | addressing on register REG in order to add AMOUNT to REG. | |
3974 | AMOUNT is negative for pre-decrement. | |
3975 | Returns 1 if the change could be made. | |
3976 | This checks all about the validity of the result of modifying INSN. */ | |
3977 | ||
3978 | static int | |
3979 | try_pre_increment (insn, reg, amount) | |
3980 | rtx insn, reg; | |
5f4f0e22 | 3981 | HOST_WIDE_INT amount; |
d7429b6a RK |
3982 | { |
3983 | register rtx use; | |
3984 | ||
3985 | /* Nonzero if we can try to make a pre-increment or pre-decrement. | |
3986 | For example, addl $4,r1; movl (r1),... can become movl +(r1),... */ | |
3987 | int pre_ok = 0; | |
3988 | /* Nonzero if we can try to make a post-increment or post-decrement. | |
3989 | For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,... | |
3990 | It is possible for both PRE_OK and POST_OK to be nonzero if the machine | |
3991 | supports both pre-inc and post-inc, or both pre-dec and post-dec. */ | |
3992 | int post_ok = 0; | |
3993 | ||
3994 | /* Nonzero if the opportunity actually requires post-inc or post-dec. */ | |
3995 | int do_post = 0; | |
3996 | ||
3997 | /* From the sign of increment, see which possibilities are conceivable | |
3998 | on this target machine. */ | |
940da324 | 3999 | if (HAVE_PRE_INCREMENT && amount > 0) |
d7429b6a | 4000 | pre_ok = 1; |
940da324 | 4001 | if (HAVE_POST_INCREMENT && amount > 0) |
d7429b6a | 4002 | post_ok = 1; |
d7429b6a | 4003 | |
940da324 | 4004 | if (HAVE_PRE_DECREMENT && amount < 0) |
d7429b6a | 4005 | pre_ok = 1; |
940da324 | 4006 | if (HAVE_POST_DECREMENT && amount < 0) |
d7429b6a | 4007 | post_ok = 1; |
d7429b6a RK |
4008 | |
4009 | if (! (pre_ok || post_ok)) | |
4010 | return 0; | |
4011 | ||
4012 | /* It is not safe to add a side effect to a jump insn | |
4013 | because if the incremented register is spilled and must be reloaded | |
4014 | there would be no way to store the incremented value back in memory. */ | |
4015 | ||
4016 | if (GET_CODE (insn) == JUMP_INSN) | |
4017 | return 0; | |
4018 | ||
4019 | use = 0; | |
4020 | if (pre_ok) | |
4021 | use = find_use_as_address (PATTERN (insn), reg, 0); | |
4022 | if (post_ok && (use == 0 || use == (rtx) 1)) | |
4023 | { | |
4024 | use = find_use_as_address (PATTERN (insn), reg, -amount); | |
4025 | do_post = 1; | |
4026 | } | |
4027 | ||
4028 | if (use == 0 || use == (rtx) 1) | |
4029 | return 0; | |
4030 | ||
4031 | if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount)) | |
4032 | return 0; | |
4033 | ||
a0fbc3a9 SC |
4034 | /* See if this combination of instruction and addressing mode exists. */ |
4035 | if (! validate_change (insn, &XEXP (use, 0), | |
38a448ca RH |
4036 | gen_rtx_fmt_e (amount > 0 |
4037 | ? (do_post ? POST_INC : PRE_INC) | |
4038 | : (do_post ? POST_DEC : PRE_DEC), | |
4039 | Pmode, reg), 0)) | |
a0fbc3a9 | 4040 | return 0; |
d7429b6a RK |
4041 | |
4042 | /* Record that this insn now has an implicit side effect on X. */ | |
38a448ca | 4043 | REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC, reg, REG_NOTES (insn)); |
d7429b6a RK |
4044 | return 1; |
4045 | } | |
4046 | ||
4047 | #endif /* AUTO_INC_DEC */ | |
4048 | \f | |
4049 | /* Find the place in the rtx X where REG is used as a memory address. | |
4050 | Return the MEM rtx that so uses it. | |
4051 | If PLUSCONST is nonzero, search instead for a memory address equivalent to | |
4052 | (plus REG (const_int PLUSCONST)). | |
4053 | ||
4054 | If such an address does not appear, return 0. | |
4055 | If REG appears more than once, or is used other than in such an address, | |
4056 | return (rtx)1. */ | |
4057 | ||
8c660648 | 4058 | rtx |
d7429b6a RK |
4059 | find_use_as_address (x, reg, plusconst) |
4060 | register rtx x; | |
4061 | rtx reg; | |
e658434c | 4062 | HOST_WIDE_INT plusconst; |
d7429b6a RK |
4063 | { |
4064 | enum rtx_code code = GET_CODE (x); | |
4065 | char *fmt = GET_RTX_FORMAT (code); | |
4066 | register int i; | |
4067 | register rtx value = 0; | |
4068 | register rtx tem; | |
4069 | ||
4070 | if (code == MEM && XEXP (x, 0) == reg && plusconst == 0) | |
4071 | return x; | |
4072 | ||
4073 | if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS | |
4074 | && XEXP (XEXP (x, 0), 0) == reg | |
4075 | && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT | |
4076 | && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst) | |
4077 | return x; | |
4078 | ||
4079 | if (code == SIGN_EXTRACT || code == ZERO_EXTRACT) | |
4080 | { | |
4081 | /* If REG occurs inside a MEM used in a bit-field reference, | |
4082 | that is unacceptable. */ | |
4083 | if (find_use_as_address (XEXP (x, 0), reg, 0) != 0) | |
6fa5c106 | 4084 | return (rtx) (HOST_WIDE_INT) 1; |
d7429b6a RK |
4085 | } |
4086 | ||
4087 | if (x == reg) | |
6fa5c106 | 4088 | return (rtx) (HOST_WIDE_INT) 1; |
d7429b6a RK |
4089 | |
4090 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
4091 | { | |
4092 | if (fmt[i] == 'e') | |
4093 | { | |
4094 | tem = find_use_as_address (XEXP (x, i), reg, plusconst); | |
4095 | if (value == 0) | |
4096 | value = tem; | |
4097 | else if (tem != 0) | |
6fa5c106 | 4098 | return (rtx) (HOST_WIDE_INT) 1; |
d7429b6a RK |
4099 | } |
4100 | if (fmt[i] == 'E') | |
4101 | { | |
4102 | register int j; | |
4103 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
4104 | { | |
4105 | tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst); | |
4106 | if (value == 0) | |
4107 | value = tem; | |
4108 | else if (tem != 0) | |
6fa5c106 | 4109 | return (rtx) (HOST_WIDE_INT) 1; |
d7429b6a RK |
4110 | } |
4111 | } | |
4112 | } | |
4113 | ||
4114 | return value; | |
4115 | } | |
4116 | \f | |
4117 | /* Write information about registers and basic blocks into FILE. | |
4118 | This is part of making a debugging dump. */ | |
4119 | ||
4120 | void | |
4121 | dump_flow_info (file) | |
4122 | FILE *file; | |
4123 | { | |
4124 | register int i; | |
4125 | static char *reg_class_names[] = REG_CLASS_NAMES; | |
4126 | ||
4127 | fprintf (file, "%d registers.\n", max_regno); | |
d7429b6a | 4128 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) |
b1f21e0a | 4129 | if (REG_N_REFS (i)) |
d7429b6a | 4130 | { |
e4600702 | 4131 | enum reg_class class, altclass; |
d7429b6a | 4132 | fprintf (file, "\nRegister %d used %d times across %d insns", |
b1f21e0a MM |
4133 | i, REG_N_REFS (i), REG_LIVE_LENGTH (i)); |
4134 | if (REG_BASIC_BLOCK (i) >= 0) | |
4135 | fprintf (file, " in block %d", REG_BASIC_BLOCK (i)); | |
6fc4610b MM |
4136 | if (REG_N_SETS (i)) |
4137 | fprintf (file, "; set %d time%s", REG_N_SETS (i), | |
4138 | (REG_N_SETS (i) == 1) ? "" : "s"); | |
4139 | if (REG_USERVAR_P (regno_reg_rtx[i])) | |
4140 | fprintf (file, "; user var"); | |
b1f21e0a MM |
4141 | if (REG_N_DEATHS (i) != 1) |
4142 | fprintf (file, "; dies in %d places", REG_N_DEATHS (i)); | |
4143 | if (REG_N_CALLS_CROSSED (i) == 1) | |
d7429b6a | 4144 | fprintf (file, "; crosses 1 call"); |
b1f21e0a MM |
4145 | else if (REG_N_CALLS_CROSSED (i)) |
4146 | fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i)); | |
d7429b6a RK |
4147 | if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD) |
4148 | fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i)); | |
4149 | class = reg_preferred_class (i); | |
e4600702 RK |
4150 | altclass = reg_alternate_class (i); |
4151 | if (class != GENERAL_REGS || altclass != ALL_REGS) | |
d7429b6a | 4152 | { |
e4600702 RK |
4153 | if (altclass == ALL_REGS || class == ALL_REGS) |
4154 | fprintf (file, "; pref %s", reg_class_names[(int) class]); | |
4155 | else if (altclass == NO_REGS) | |
d7429b6a RK |
4156 | fprintf (file, "; %s or none", reg_class_names[(int) class]); |
4157 | else | |
e4600702 RK |
4158 | fprintf (file, "; pref %s, else %s", |
4159 | reg_class_names[(int) class], | |
4160 | reg_class_names[(int) altclass]); | |
d7429b6a RK |
4161 | } |
4162 | if (REGNO_POINTER_FLAG (i)) | |
4163 | fprintf (file, "; pointer"); | |
4164 | fprintf (file, ".\n"); | |
4165 | } | |
e881bb1b | 4166 | |
d7429b6a | 4167 | fprintf (file, "\n%d basic blocks.\n", n_basic_blocks); |
e881bb1b RH |
4168 | for (i = 0; i < n_basic_blocks; i++) |
4169 | { | |
4170 | register basic_block bb = BASIC_BLOCK (i); | |
4171 | register int regno; | |
4172 | register edge e; | |
4173 | ||
4174 | fprintf (file, "\nBasic block %d: first insn %d, last %d.\n", | |
4175 | i, INSN_UID (bb->head), INSN_UID (bb->end)); | |
4176 | ||
4177 | fprintf (file, "Predecessors: "); | |
4178 | for (e = bb->pred; e ; e = e->pred_next) | |
4179 | dump_edge_info (file, e, 0); | |
4180 | ||
4181 | fprintf (file, "\nSuccessors: "); | |
4182 | for (e = bb->succ; e ; e = e->succ_next) | |
4183 | dump_edge_info (file, e, 1); | |
4184 | ||
4185 | fprintf (file, "\nRegisters live at start:"); | |
4186 | if (bb->global_live_at_start) | |
4187 | { | |
4188 | for (regno = 0; regno < max_regno; regno++) | |
4189 | if (REGNO_REG_SET_P (bb->global_live_at_start, regno)) | |
4190 | fprintf (file, " %d", regno); | |
4191 | } | |
4192 | else | |
4193 | fprintf (file, " n/a"); | |
4194 | ||
4195 | fprintf (file, "\nRegisters live at end:"); | |
4196 | if (bb->global_live_at_end) | |
4197 | { | |
4198 | for (regno = 0; regno < max_regno; regno++) | |
4199 | if (REGNO_REG_SET_P (bb->global_live_at_end, regno)) | |
4200 | fprintf (file, " %d", regno); | |
4201 | } | |
4202 | else | |
4203 | fprintf (file, " n/a"); | |
4204 | ||
4205 | putc('\n', file); | |
4206 | } | |
4207 | ||
4208 | putc('\n', file); | |
4209 | } | |
4210 | ||
4211 | static void | |
4212 | dump_edge_info (file, e, do_succ) | |
4213 | FILE *file; | |
4214 | edge e; | |
4215 | int do_succ; | |
4216 | { | |
4217 | basic_block side = (do_succ ? e->dest : e->src); | |
4218 | ||
4219 | if (side == ENTRY_BLOCK_PTR) | |
4220 | fputs (" ENTRY", file); | |
4221 | else if (side == EXIT_BLOCK_PTR) | |
4222 | fputs (" EXIT", file); | |
4223 | else | |
4224 | fprintf (file, " %d", side->index); | |
4225 | ||
4226 | if (e->flags) | |
4227 | { | |
4228 | static char * bitnames[] = { | |
4229 | "fallthru", "crit", "ab", "abcall", "eh", "fake" | |
4230 | }; | |
4231 | int comma = 0; | |
4232 | int i, flags = e->flags; | |
4233 | ||
4234 | fputc (' ', file); | |
4235 | fputc ('(', file); | |
4236 | for (i = 0; flags; i++) | |
4237 | if (flags & (1 << i)) | |
4238 | { | |
4239 | flags &= ~(1 << i); | |
4240 | ||
4241 | if (comma) | |
4242 | fputc (',', file); | |
4243 | if (i < (int)(sizeof (bitnames) / sizeof (*bitnames))) | |
4244 | fputs (bitnames[i], file); | |
4245 | else | |
4246 | fprintf (file, "%d", i); | |
4247 | comma = 1; | |
4248 | } | |
4249 | fputc (')', file); | |
4250 | } | |
d7429b6a | 4251 | } |
3e28fe44 MM |
4252 | |
4253 | \f | |
4254 | /* Like print_rtl, but also print out live information for the start of each | |
4255 | basic block. */ | |
4256 | ||
4257 | void | |
4258 | print_rtl_with_bb (outf, rtx_first) | |
4259 | FILE *outf; | |
4260 | rtx rtx_first; | |
4261 | { | |
4262 | register rtx tmp_rtx; | |
4263 | ||
4264 | if (rtx_first == 0) | |
4265 | fprintf (outf, "(nil)\n"); | |
3e28fe44 MM |
4266 | else |
4267 | { | |
e881bb1b | 4268 | int i; |
3e28fe44 MM |
4269 | enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB }; |
4270 | int max_uid = get_max_uid (); | |
54ea1de9 KG |
4271 | basic_block *start = (basic_block *) |
4272 | alloca (max_uid * sizeof (basic_block)); | |
4273 | basic_block *end = (basic_block *) | |
4274 | alloca (max_uid * sizeof (basic_block)); | |
2a92c071 GS |
4275 | enum bb_state *in_bb_p = (enum bb_state *) |
4276 | alloca (max_uid * sizeof (enum bb_state)); | |
3e28fe44 | 4277 | |
e881bb1b RH |
4278 | memset (start, 0, max_uid * sizeof (basic_block)); |
4279 | memset (end, 0, max_uid * sizeof (basic_block)); | |
4280 | memset (in_bb_p, 0, max_uid * sizeof (enum bb_state)); | |
3e28fe44 | 4281 | |
e881bb1b | 4282 | for (i = n_basic_blocks - 1; i >= 0; i--) |
3e28fe44 | 4283 | { |
e881bb1b | 4284 | basic_block bb = BASIC_BLOCK (i); |
3e28fe44 | 4285 | rtx x; |
e881bb1b RH |
4286 | |
4287 | start[INSN_UID (bb->head)] = bb; | |
4288 | end[INSN_UID (bb->end)] = bb; | |
4289 | for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x)) | |
3e28fe44 | 4290 | { |
e881bb1b RH |
4291 | enum bb_state state = IN_MULTIPLE_BB; |
4292 | if (in_bb_p[INSN_UID(x)] == NOT_IN_BB) | |
4293 | state = IN_ONE_BB; | |
4294 | in_bb_p[INSN_UID(x)] = state; | |
4295 | ||
4296 | if (x == bb->end) | |
3e28fe44 MM |
4297 | break; |
4298 | } | |
4299 | } | |
4300 | ||
4301 | for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx)) | |
4302 | { | |
b707b450 | 4303 | int did_output; |
e881bb1b | 4304 | basic_block bb; |
b707b450 | 4305 | |
e881bb1b | 4306 | if ((bb = start[INSN_UID (tmp_rtx)]) != NULL) |
3e28fe44 MM |
4307 | { |
4308 | fprintf (outf, ";; Start of basic block %d, registers live:", | |
e881bb1b | 4309 | bb->index); |
3e28fe44 | 4310 | |
e881bb1b | 4311 | EXECUTE_IF_SET_IN_REG_SET (bb->global_live_at_start, 0, i, |
3e28fe44 MM |
4312 | { |
4313 | fprintf (outf, " %d", i); | |
4314 | if (i < FIRST_PSEUDO_REGISTER) | |
4315 | fprintf (outf, " [%s]", | |
4316 | reg_names[i]); | |
4317 | }); | |
4318 | putc ('\n', outf); | |
4319 | } | |
4320 | ||
ab87f8c8 | 4321 | if (in_bb_p[INSN_UID(tmp_rtx)] == NOT_IN_BB |
3e28fe44 | 4322 | && GET_CODE (tmp_rtx) != NOTE |
ab87f8c8 JL |
4323 | && GET_CODE (tmp_rtx) != BARRIER |
4324 | && ! obey_regdecls) | |
3e28fe44 | 4325 | fprintf (outf, ";; Insn is not within a basic block\n"); |
e881bb1b | 4326 | else if (in_bb_p[INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB) |
3e28fe44 MM |
4327 | fprintf (outf, ";; Insn is in multiple basic blocks\n"); |
4328 | ||
b707b450 | 4329 | did_output = print_rtl_single (outf, tmp_rtx); |
3e28fe44 | 4330 | |
e881bb1b RH |
4331 | if ((bb = end[INSN_UID (tmp_rtx)]) != NULL) |
4332 | fprintf (outf, ";; End of basic block %d\n", bb->index); | |
3e28fe44 | 4333 | |
b707b450 | 4334 | if (did_output) |
9ec36da5 | 4335 | putc ('\n', outf); |
3e28fe44 MM |
4336 | } |
4337 | } | |
4338 | } | |
5ece9746 JL |
4339 | |
4340 | \f | |
4341 | /* Integer list support. */ | |
4342 | ||
4343 | /* Allocate a node from list *HEAD_PTR. */ | |
4344 | ||
4345 | static int_list_ptr | |
4346 | alloc_int_list_node (head_ptr) | |
4347 | int_list_block **head_ptr; | |
4348 | { | |
4349 | struct int_list_block *first_blk = *head_ptr; | |
4350 | ||
4351 | if (first_blk == NULL || first_blk->nodes_left <= 0) | |
4352 | { | |
4353 | first_blk = (struct int_list_block *) xmalloc (sizeof (struct int_list_block)); | |
4354 | first_blk->nodes_left = INT_LIST_NODES_IN_BLK; | |
4355 | first_blk->next = *head_ptr; | |
4356 | *head_ptr = first_blk; | |
4357 | } | |
4358 | ||
4359 | first_blk->nodes_left--; | |
4360 | return &first_blk->nodes[first_blk->nodes_left]; | |
4361 | } | |
4362 | ||
4363 | /* Pointer to head of predecessor/successor block list. */ | |
4364 | static int_list_block *pred_int_list_blocks; | |
4365 | ||
4366 | /* Add a new node to integer list LIST with value VAL. | |
4367 | LIST is a pointer to a list object to allow for different implementations. | |
4368 | If *LIST is initially NULL, the list is empty. | |
4369 | The caller must not care whether the element is added to the front or | |
4370 | to the end of the list (to allow for different implementations). */ | |
4371 | ||
4372 | static int_list_ptr | |
4373 | add_int_list_node (blk_list, list, val) | |
4374 | int_list_block **blk_list; | |
4375 | int_list **list; | |
4376 | int val; | |
4377 | { | |
4378 | int_list_ptr p = alloc_int_list_node (blk_list); | |
4379 | ||
4380 | p->val = val; | |
4381 | p->next = *list; | |
4382 | *list = p; | |
4383 | return p; | |
4384 | } | |
4385 | ||
4386 | /* Free the blocks of lists at BLK_LIST. */ | |
4387 | ||
4388 | void | |
4389 | free_int_list (blk_list) | |
4390 | int_list_block **blk_list; | |
4391 | { | |
4392 | int_list_block *p, *next; | |
4393 | ||
4394 | for (p = *blk_list; p != NULL; p = next) | |
4395 | { | |
4396 | next = p->next; | |
4397 | free (p); | |
4398 | } | |
4399 | ||
4400 | /* Mark list as empty for the next function we compile. */ | |
4401 | *blk_list = NULL; | |
4402 | } | |
4403 | \f | |
4404 | /* Predecessor/successor computation. */ | |
4405 | ||
4406 | /* Mark PRED_BB a precessor of SUCC_BB, | |
4407 | and conversely SUCC_BB a successor of PRED_BB. */ | |
4408 | ||
4409 | static void | |
4410 | add_pred_succ (pred_bb, succ_bb, s_preds, s_succs, num_preds, num_succs) | |
4411 | int pred_bb; | |
4412 | int succ_bb; | |
4413 | int_list_ptr *s_preds; | |
4414 | int_list_ptr *s_succs; | |
4415 | int *num_preds; | |
4416 | int *num_succs; | |
4417 | { | |
4418 | if (succ_bb != EXIT_BLOCK) | |
4419 | { | |
4420 | add_int_list_node (&pred_int_list_blocks, &s_preds[succ_bb], pred_bb); | |
4421 | num_preds[succ_bb]++; | |
4422 | } | |
4423 | if (pred_bb != ENTRY_BLOCK) | |
4424 | { | |
4425 | add_int_list_node (&pred_int_list_blocks, &s_succs[pred_bb], succ_bb); | |
4426 | num_succs[pred_bb]++; | |
4427 | } | |
4428 | } | |
4429 | ||
e881bb1b RH |
4430 | /* Convert edge lists into pred/succ lists for backward compatibility. */ |
4431 | ||
743bb12d | 4432 | void |
5ece9746 JL |
4433 | compute_preds_succs (s_preds, s_succs, num_preds, num_succs) |
4434 | int_list_ptr *s_preds; | |
4435 | int_list_ptr *s_succs; | |
4436 | int *num_preds; | |
4437 | int *num_succs; | |
4438 | { | |
e881bb1b RH |
4439 | int i, n = n_basic_blocks; |
4440 | edge e; | |
5ece9746 | 4441 | |
e881bb1b RH |
4442 | memset (s_preds, 0, n_basic_blocks * sizeof (int_list_ptr)); |
4443 | memset (s_succs, 0, n_basic_blocks * sizeof (int_list_ptr)); | |
4444 | memset (num_preds, 0, n_basic_blocks * sizeof (int)); | |
4445 | memset (num_succs, 0, n_basic_blocks * sizeof (int)); | |
5ece9746 | 4446 | |
e881bb1b | 4447 | for (i = 0; i < n; ++i) |
5ece9746 | 4448 | { |
e881bb1b RH |
4449 | basic_block bb = BASIC_BLOCK (i); |
4450 | ||
4451 | for (e = bb->succ; e ; e = e->succ_next) | |
4452 | add_pred_succ (i, e->dest->index, s_preds, s_succs, | |
4453 | num_preds, num_succs); | |
5ece9746 JL |
4454 | } |
4455 | ||
e881bb1b RH |
4456 | for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next) |
4457 | add_pred_succ (ENTRY_BLOCK, e->dest->index, s_preds, s_succs, | |
4458 | num_preds, num_succs); | |
5ece9746 JL |
4459 | } |
4460 | ||
4461 | void | |
421382ac | 4462 | dump_bb_data (file, preds, succs, live_info) |
5ece9746 JL |
4463 | FILE *file; |
4464 | int_list_ptr *preds; | |
4465 | int_list_ptr *succs; | |
421382ac | 4466 | int live_info; |
5ece9746 JL |
4467 | { |
4468 | int bb; | |
4469 | int_list_ptr p; | |
4470 | ||
4471 | fprintf (file, "BB data\n\n"); | |
4472 | for (bb = 0; bb < n_basic_blocks; bb++) | |
4473 | { | |
4474 | fprintf (file, "BB %d, start %d, end %d\n", bb, | |
4475 | INSN_UID (BLOCK_HEAD (bb)), INSN_UID (BLOCK_END (bb))); | |
4476 | fprintf (file, " preds:"); | |
4477 | for (p = preds[bb]; p != NULL; p = p->next) | |
4478 | { | |
4479 | int pred_bb = INT_LIST_VAL (p); | |
4480 | if (pred_bb == ENTRY_BLOCK) | |
4481 | fprintf (file, " entry"); | |
4482 | else | |
4483 | fprintf (file, " %d", pred_bb); | |
4484 | } | |
4485 | fprintf (file, "\n"); | |
4486 | fprintf (file, " succs:"); | |
4487 | for (p = succs[bb]; p != NULL; p = p->next) | |
4488 | { | |
4489 | int succ_bb = INT_LIST_VAL (p); | |
4490 | if (succ_bb == EXIT_BLOCK) | |
4491 | fprintf (file, " exit"); | |
4492 | else | |
4493 | fprintf (file, " %d", succ_bb); | |
4494 | } | |
421382ac BS |
4495 | if (live_info) |
4496 | { | |
4497 | int regno; | |
4498 | fprintf (file, "\nRegisters live at start:"); | |
4499 | for (regno = 0; regno < max_regno; regno++) | |
e881bb1b | 4500 | if (REGNO_REG_SET_P (BASIC_BLOCK (bb)->global_live_at_start, regno)) |
421382ac BS |
4501 | fprintf (file, " %d", regno); |
4502 | fprintf (file, "\n"); | |
4503 | } | |
5ece9746 JL |
4504 | fprintf (file, "\n"); |
4505 | } | |
4506 | fprintf (file, "\n"); | |
4507 | } | |
4508 | ||
4509 | /* Free basic block data storage. */ | |
4510 | ||
4511 | void | |
4512 | free_bb_mem () | |
4513 | { | |
4514 | free_int_list (&pred_int_list_blocks); | |
4515 | } | |
5e89e58b | 4516 | |
5ece9746 JL |
4517 | /* Compute dominator relationships. */ |
4518 | void | |
4519 | compute_dominators (dominators, post_dominators, s_preds, s_succs) | |
4520 | sbitmap *dominators; | |
4521 | sbitmap *post_dominators; | |
4522 | int_list_ptr *s_preds; | |
4523 | int_list_ptr *s_succs; | |
4524 | { | |
4525 | int bb, changed, passes; | |
4526 | sbitmap *temp_bitmap; | |
4527 | ||
4528 | temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks); | |
4529 | sbitmap_vector_ones (dominators, n_basic_blocks); | |
4530 | sbitmap_vector_ones (post_dominators, n_basic_blocks); | |
4531 | sbitmap_vector_zero (temp_bitmap, n_basic_blocks); | |
4532 | ||
4533 | sbitmap_zero (dominators[0]); | |
4534 | SET_BIT (dominators[0], 0); | |
4535 | ||
e881bb1b RH |
4536 | sbitmap_zero (post_dominators[n_basic_blocks - 1]); |
4537 | SET_BIT (post_dominators[n_basic_blocks - 1], 0); | |
5ece9746 JL |
4538 | |
4539 | passes = 0; | |
4540 | changed = 1; | |
4541 | while (changed) | |
4542 | { | |
4543 | changed = 0; | |
4544 | for (bb = 1; bb < n_basic_blocks; bb++) | |
4545 | { | |
4546 | sbitmap_intersect_of_predecessors (temp_bitmap[bb], dominators, | |
4547 | bb, s_preds); | |
4548 | SET_BIT (temp_bitmap[bb], bb); | |
4549 | changed |= sbitmap_a_and_b (dominators[bb], | |
4550 | dominators[bb], | |
4551 | temp_bitmap[bb]); | |
4552 | sbitmap_intersect_of_successors (temp_bitmap[bb], post_dominators, | |
4553 | bb, s_succs); | |
4554 | SET_BIT (temp_bitmap[bb], bb); | |
4555 | changed |= sbitmap_a_and_b (post_dominators[bb], | |
4556 | post_dominators[bb], | |
4557 | temp_bitmap[bb]); | |
4558 | } | |
4559 | passes++; | |
4560 | } | |
4561 | ||
4562 | free (temp_bitmap); | |
4563 | } | |
4c649323 | 4564 | |
422d0fb0 RH |
4565 | /* Given DOMINATORS, compute the immediate dominators into IDOM. */ |
4566 | ||
4567 | void | |
4568 | compute_immediate_dominators (idom, dominators) | |
4569 | int *idom; | |
4570 | sbitmap *dominators; | |
4571 | { | |
4572 | sbitmap *tmp; | |
4573 | int b; | |
4574 | ||
4575 | tmp = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks); | |
4576 | ||
4577 | /* Begin with tmp(n) = dom(n) - { n }. */ | |
4578 | for (b = n_basic_blocks; --b >= 0; ) | |
4579 | { | |
4580 | sbitmap_copy (tmp[b], dominators[b]); | |
4581 | RESET_BIT (tmp[b], b); | |
4582 | } | |
4583 | ||
4584 | /* Subtract out all of our dominator's dominators. */ | |
4585 | for (b = n_basic_blocks; --b >= 0; ) | |
4586 | { | |
4587 | sbitmap tmp_b = tmp[b]; | |
4588 | int s; | |
4589 | ||
4590 | for (s = n_basic_blocks; --s >= 0; ) | |
4591 | if (TEST_BIT (tmp_b, s)) | |
4592 | sbitmap_difference (tmp_b, tmp_b, tmp[s]); | |
4593 | } | |
4594 | ||
4595 | /* Find the one bit set in the bitmap and put it in the output array. */ | |
4596 | for (b = n_basic_blocks; --b >= 0; ) | |
4597 | { | |
4598 | int t; | |
4599 | EXECUTE_IF_SET_IN_SBITMAP (tmp[b], 0, t, { idom[b] = t; }); | |
4600 | } | |
4601 | ||
4602 | sbitmap_vector_free (tmp); | |
4603 | } | |
4604 | ||
4c649323 JL |
4605 | /* Count for a single SET rtx, X. */ |
4606 | ||
4607 | static void | |
4608 | count_reg_sets_1 (x) | |
4609 | rtx x; | |
4610 | { | |
4611 | register int regno; | |
4612 | register rtx reg = SET_DEST (x); | |
4613 | ||
4614 | /* Find the register that's set/clobbered. */ | |
4615 | while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT | |
4616 | || GET_CODE (reg) == SIGN_EXTRACT | |
4617 | || GET_CODE (reg) == STRICT_LOW_PART) | |
4618 | reg = XEXP (reg, 0); | |
4619 | ||
86465af7 DM |
4620 | if (GET_CODE (reg) == PARALLEL |
4621 | && GET_MODE (reg) == BLKmode) | |
4622 | { | |
4623 | register int i; | |
4624 | for (i = XVECLEN (reg, 0) - 1; i >= 0; i--) | |
4625 | count_reg_sets_1 (XVECEXP (reg, 0, i)); | |
4626 | return; | |
4627 | } | |
4628 | ||
4c649323 JL |
4629 | if (GET_CODE (reg) == REG) |
4630 | { | |
4631 | regno = REGNO (reg); | |
4632 | if (regno >= FIRST_PSEUDO_REGISTER) | |
4633 | { | |
4634 | /* Count (weighted) references, stores, etc. This counts a | |
4635 | register twice if it is modified, but that is correct. */ | |
4636 | REG_N_SETS (regno)++; | |
4637 | ||
4638 | REG_N_REFS (regno) += loop_depth; | |
4639 | } | |
4640 | } | |
4641 | } | |
4642 | ||
4643 | /* Increment REG_N_SETS for each SET or CLOBBER found in X; also increment | |
4644 | REG_N_REFS by the current loop depth for each SET or CLOBBER found. */ | |
4645 | ||
4646 | static void | |
4647 | count_reg_sets (x) | |
4648 | rtx x; | |
4649 | { | |
4650 | register RTX_CODE code = GET_CODE (x); | |
4651 | ||
4652 | if (code == SET || code == CLOBBER) | |
4653 | count_reg_sets_1 (x); | |
4654 | else if (code == PARALLEL) | |
4655 | { | |
4656 | register int i; | |
4657 | for (i = XVECLEN (x, 0) - 1; i >= 0; i--) | |
4658 | { | |
4659 | code = GET_CODE (XVECEXP (x, 0, i)); | |
4660 | if (code == SET || code == CLOBBER) | |
4661 | count_reg_sets_1 (XVECEXP (x, 0, i)); | |
4662 | } | |
4663 | } | |
4664 | } | |
4665 | ||
4666 | /* Increment REG_N_REFS by the current loop depth each register reference | |
4667 | found in X. */ | |
4668 | ||
4669 | static void | |
4670 | count_reg_references (x) | |
4671 | rtx x; | |
4672 | { | |
4673 | register RTX_CODE code; | |
4c649323 JL |
4674 | |
4675 | retry: | |
4676 | code = GET_CODE (x); | |
4677 | switch (code) | |
4678 | { | |
4679 | case LABEL_REF: | |
4680 | case SYMBOL_REF: | |
4681 | case CONST_INT: | |
4682 | case CONST: | |
4683 | case CONST_DOUBLE: | |
4684 | case PC: | |
4685 | case ADDR_VEC: | |
4686 | case ADDR_DIFF_VEC: | |
4687 | case ASM_INPUT: | |
4688 | return; | |
4689 | ||
4690 | #ifdef HAVE_cc0 | |
4691 | case CC0: | |
4692 | return; | |
4693 | #endif | |
4694 | ||
4695 | case CLOBBER: | |
4696 | /* If we are clobbering a MEM, mark any registers inside the address | |
4697 | as being used. */ | |
4698 | if (GET_CODE (XEXP (x, 0)) == MEM) | |
4699 | count_reg_references (XEXP (XEXP (x, 0), 0)); | |
4700 | return; | |
4701 | ||
4702 | case SUBREG: | |
4703 | /* While we're here, optimize this case. */ | |
4704 | x = SUBREG_REG (x); | |
4705 | ||
4706 | /* In case the SUBREG is not of a register, don't optimize */ | |
4707 | if (GET_CODE (x) != REG) | |
4708 | { | |
4709 | count_reg_references (x); | |
4710 | return; | |
4711 | } | |
4712 | ||
4713 | /* ... fall through ... */ | |
4714 | ||
4715 | case REG: | |
4716 | if (REGNO (x) >= FIRST_PSEUDO_REGISTER) | |
4717 | REG_N_REFS (REGNO (x)) += loop_depth; | |
4718 | return; | |
4719 | ||
4720 | case SET: | |
4721 | { | |
4722 | register rtx testreg = SET_DEST (x); | |
4723 | int mark_dest = 0; | |
4724 | ||
4725 | /* If storing into MEM, don't show it as being used. But do | |
4726 | show the address as being used. */ | |
4727 | if (GET_CODE (testreg) == MEM) | |
4728 | { | |
4729 | count_reg_references (XEXP (testreg, 0)); | |
4730 | count_reg_references (SET_SRC (x)); | |
4731 | return; | |
4732 | } | |
4733 | ||
4734 | /* Storing in STRICT_LOW_PART is like storing in a reg | |
4735 | in that this SET might be dead, so ignore it in TESTREG. | |
4736 | but in some other ways it is like using the reg. | |
4737 | ||
4738 | Storing in a SUBREG or a bit field is like storing the entire | |
4739 | register in that if the register's value is not used | |
4740 | then this SET is not needed. */ | |
4741 | while (GET_CODE (testreg) == STRICT_LOW_PART | |
4742 | || GET_CODE (testreg) == ZERO_EXTRACT | |
4743 | || GET_CODE (testreg) == SIGN_EXTRACT | |
4744 | || GET_CODE (testreg) == SUBREG) | |
4745 | { | |
4746 | /* Modifying a single register in an alternate mode | |
4747 | does not use any of the old value. But these other | |
4748 | ways of storing in a register do use the old value. */ | |
4749 | if (GET_CODE (testreg) == SUBREG | |
4750 | && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg))) | |
4751 | ; | |
4752 | else | |
4753 | mark_dest = 1; | |
4754 | ||
4755 | testreg = XEXP (testreg, 0); | |
4756 | } | |
4757 | ||
4758 | /* If this is a store into a register, | |
4759 | recursively scan the value being stored. */ | |
4760 | ||
86465af7 DM |
4761 | if ((GET_CODE (testreg) == PARALLEL |
4762 | && GET_MODE (testreg) == BLKmode) | |
4763 | || GET_CODE (testreg) == REG) | |
4c649323 JL |
4764 | { |
4765 | count_reg_references (SET_SRC (x)); | |
4766 | if (mark_dest) | |
4767 | count_reg_references (SET_DEST (x)); | |
4768 | return; | |
4769 | } | |
4770 | } | |
4771 | break; | |
4772 | ||
4773 | default: | |
4774 | break; | |
4775 | } | |
4776 | ||
4777 | /* Recursively scan the operands of this expression. */ | |
4778 | ||
4779 | { | |
4780 | register char *fmt = GET_RTX_FORMAT (code); | |
4781 | register int i; | |
4782 | ||
4783 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
4784 | { | |
4785 | if (fmt[i] == 'e') | |
4786 | { | |
4787 | /* Tail recursive case: save a function call level. */ | |
4788 | if (i == 0) | |
4789 | { | |
4790 | x = XEXP (x, 0); | |
4791 | goto retry; | |
4792 | } | |
4793 | count_reg_references (XEXP (x, i)); | |
4794 | } | |
4795 | else if (fmt[i] == 'E') | |
4796 | { | |
4797 | register int j; | |
4798 | for (j = 0; j < XVECLEN (x, i); j++) | |
4799 | count_reg_references (XVECEXP (x, i, j)); | |
4800 | } | |
4801 | } | |
4802 | } | |
4803 | } | |
4804 | ||
4805 | /* Recompute register set/reference counts immediately prior to register | |
4806 | allocation. | |
4807 | ||
4808 | This avoids problems with set/reference counts changing to/from values | |
4809 | which have special meanings to the register allocators. | |
4810 | ||
4811 | Additionally, the reference counts are the primary component used by the | |
4812 | register allocators to prioritize pseudos for allocation to hard regs. | |
4813 | More accurate reference counts generally lead to better register allocation. | |
4814 | ||
213c4983 R |
4815 | F is the first insn to be scanned. |
4816 | LOOP_STEP denotes how much loop_depth should be incremented per | |
4817 | loop nesting level in order to increase the ref count more for references | |
4818 | in a loop. | |
4819 | ||
4c649323 JL |
4820 | It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and |
4821 | possibly other information which is used by the register allocators. */ | |
4822 | ||
762a1d90 | 4823 | void |
213c4983 | 4824 | recompute_reg_usage (f, loop_step) |
4c649323 | 4825 | rtx f; |
213c4983 | 4826 | int loop_step; |
4c649323 JL |
4827 | { |
4828 | rtx insn; | |
4829 | int i, max_reg; | |
4830 | ||
4831 | /* Clear out the old data. */ | |
4832 | max_reg = max_reg_num (); | |
4833 | for (i = FIRST_PSEUDO_REGISTER; i < max_reg; i++) | |
4834 | { | |
4835 | REG_N_SETS (i) = 0; | |
4836 | REG_N_REFS (i) = 0; | |
4837 | } | |
4838 | ||
4839 | /* Scan each insn in the chain and count how many times each register is | |
4840 | set/used. */ | |
4841 | loop_depth = 1; | |
4842 | for (insn = f; insn; insn = NEXT_INSN (insn)) | |
4843 | { | |
4844 | /* Keep track of loop depth. */ | |
4845 | if (GET_CODE (insn) == NOTE) | |
4846 | { | |
4847 | /* Look for loop boundaries. */ | |
4848 | if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) | |
213c4983 | 4849 | loop_depth -= loop_step; |
4c649323 | 4850 | else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) |
213c4983 | 4851 | loop_depth += loop_step; |
4c649323 JL |
4852 | |
4853 | /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error. | |
4854 | Abort now rather than setting register status incorrectly. */ | |
4855 | if (loop_depth == 0) | |
4856 | abort (); | |
4857 | } | |
4858 | else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') | |
4859 | { | |
4860 | rtx links; | |
4861 | ||
4862 | /* This call will increment REG_N_SETS for each SET or CLOBBER | |
4863 | of a register in INSN. It will also increment REG_N_REFS | |
4864 | by the loop depth for each set of a register in INSN. */ | |
4865 | count_reg_sets (PATTERN (insn)); | |
4866 | ||
4867 | /* count_reg_sets does not detect autoincrement address modes, so | |
4868 | detect them here by looking at the notes attached to INSN. */ | |
4869 | for (links = REG_NOTES (insn); links; links = XEXP (links, 1)) | |
4870 | { | |
4871 | if (REG_NOTE_KIND (links) == REG_INC) | |
4872 | /* Count (weighted) references, stores, etc. This counts a | |
4873 | register twice if it is modified, but that is correct. */ | |
4874 | REG_N_SETS (REGNO (XEXP (links, 0)))++; | |
4875 | } | |
4876 | ||
4877 | /* This call will increment REG_N_REFS by the current loop depth for | |
4878 | each reference to a register in INSN. */ | |
4879 | count_reg_references (PATTERN (insn)); | |
4880 | ||
4881 | /* count_reg_references will not include counts for arguments to | |
4882 | function calls, so detect them here by examining the | |
4883 | CALL_INSN_FUNCTION_USAGE data. */ | |
4884 | if (GET_CODE (insn) == CALL_INSN) | |
4885 | { | |
4886 | rtx note; | |
4887 | ||
4888 | for (note = CALL_INSN_FUNCTION_USAGE (insn); | |
4889 | note; | |
4890 | note = XEXP (note, 1)) | |
4891 | if (GET_CODE (XEXP (note, 0)) == USE) | |
4892 | count_reg_references (SET_DEST (XEXP (note, 0))); | |
4893 | } | |
4894 | } | |
4895 | } | |
4896 | } | |
e881bb1b RH |
4897 | |
4898 | /* Record INSN's block as BB. */ | |
4899 | ||
4900 | void | |
4901 | set_block_for_insn (insn, bb) | |
4902 | rtx insn; | |
4903 | basic_block bb; | |
4904 | { | |
4905 | size_t uid = INSN_UID (insn); | |
4906 | if (uid >= basic_block_for_insn->num_elements) | |
4907 | { | |
4908 | int new_size; | |
4909 | ||
4910 | /* Add one-eighth the size so we don't keep calling xrealloc. */ | |
4911 | new_size = uid + (uid + 7) / 8; | |
4912 | ||
4913 | VARRAY_GROW (basic_block_for_insn, new_size); | |
4914 | } | |
4915 | VARRAY_BB (basic_block_for_insn, uid) = bb; | |
4916 | } | |
4917 | ||
4918 | /* Record INSN's block number as BB. */ | |
4919 | /* ??? This has got to go. */ | |
4920 | ||
4921 | void | |
4922 | set_block_num (insn, bb) | |
4923 | rtx insn; | |
4924 | int bb; | |
4925 | { | |
4926 | set_block_for_insn (insn, BASIC_BLOCK (bb)); | |
4927 | } |