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e45425ec | 1 | /* Partial redundancy elimination / Hoisting for RTL. |
d1e082c2 | 2 | Copyright (C) 1997-2013 Free Software Foundation, Inc. |
7506f491 | 3 | |
1322177d | 4 | This file is part of GCC. |
7506f491 | 5 | |
1322177d LB |
6 | GCC is free software; you can redistribute it and/or modify it under |
7 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 8 | Software Foundation; either version 3, or (at your option) any later |
1322177d | 9 | version. |
7506f491 | 10 | |
1322177d LB |
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
7506f491 DE |
15 | |
16 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
7506f491 DE |
19 | |
20 | /* TODO | |
21 | - reordering of memory allocation and freeing to be more space efficient | |
b11f0116 BC |
22 | - calc rough register pressure information and use the info to drive all |
23 | kinds of code motion (including code hoisting) in a unified way. | |
7506f491 DE |
24 | */ |
25 | ||
26 | /* References searched while implementing this. | |
7506f491 DE |
27 | |
28 | Compilers Principles, Techniques and Tools | |
29 | Aho, Sethi, Ullman | |
30 | Addison-Wesley, 1988 | |
31 | ||
32 | Global Optimization by Suppression of Partial Redundancies | |
33 | E. Morel, C. Renvoise | |
34 | communications of the acm, Vol. 22, Num. 2, Feb. 1979 | |
35 | ||
36 | A Portable Machine-Independent Global Optimizer - Design and Measurements | |
37 | Frederick Chow | |
38 | Stanford Ph.D. thesis, Dec. 1983 | |
39 | ||
7506f491 DE |
40 | A Fast Algorithm for Code Movement Optimization |
41 | D.M. Dhamdhere | |
42 | SIGPLAN Notices, Vol. 23, Num. 10, Oct. 1988 | |
43 | ||
44 | A Solution to a Problem with Morel and Renvoise's | |
45 | Global Optimization by Suppression of Partial Redundancies | |
46 | K-H Drechsler, M.P. Stadel | |
47 | ACM TOPLAS, Vol. 10, Num. 4, Oct. 1988 | |
48 | ||
49 | Practical Adaptation of the Global Optimization | |
50 | Algorithm of Morel and Renvoise | |
51 | D.M. Dhamdhere | |
52 | ACM TOPLAS, Vol. 13, Num. 2. Apr. 1991 | |
53 | ||
54 | Efficiently Computing Static Single Assignment Form and the Control | |
55 | Dependence Graph | |
56 | R. Cytron, J. Ferrante, B.K. Rosen, M.N. Wegman, and F.K. Zadeck | |
57 | ACM TOPLAS, Vol. 13, Num. 4, Oct. 1991 | |
58 | ||
7506f491 DE |
59 | Lazy Code Motion |
60 | J. Knoop, O. Ruthing, B. Steffen | |
61 | ACM SIGPLAN Notices Vol. 27, Num. 7, Jul. 1992, '92 Conference on PLDI | |
62 | ||
63 | What's In a Region? Or Computing Control Dependence Regions in Near-Linear | |
64 | Time for Reducible Flow Control | |
65 | Thomas Ball | |
66 | ACM Letters on Programming Languages and Systems, | |
67 | Vol. 2, Num. 1-4, Mar-Dec 1993 | |
68 | ||
69 | An Efficient Representation for Sparse Sets | |
70 | Preston Briggs, Linda Torczon | |
71 | ACM Letters on Programming Languages and Systems, | |
72 | Vol. 2, Num. 1-4, Mar-Dec 1993 | |
73 | ||
74 | A Variation of Knoop, Ruthing, and Steffen's Lazy Code Motion | |
75 | K-H Drechsler, M.P. Stadel | |
76 | ACM SIGPLAN Notices, Vol. 28, Num. 5, May 1993 | |
77 | ||
78 | Partial Dead Code Elimination | |
79 | J. Knoop, O. Ruthing, B. Steffen | |
80 | ACM SIGPLAN Notices, Vol. 29, Num. 6, Jun. 1994 | |
81 | ||
82 | Effective Partial Redundancy Elimination | |
83 | P. Briggs, K.D. Cooper | |
84 | ACM SIGPLAN Notices, Vol. 29, Num. 6, Jun. 1994 | |
85 | ||
86 | The Program Structure Tree: Computing Control Regions in Linear Time | |
87 | R. Johnson, D. Pearson, K. Pingali | |
88 | ACM SIGPLAN Notices, Vol. 29, Num. 6, Jun. 1994 | |
89 | ||
90 | Optimal Code Motion: Theory and Practice | |
91 | J. Knoop, O. Ruthing, B. Steffen | |
92 | ACM TOPLAS, Vol. 16, Num. 4, Jul. 1994 | |
93 | ||
94 | The power of assignment motion | |
95 | J. Knoop, O. Ruthing, B. Steffen | |
96 | ACM SIGPLAN Notices Vol. 30, Num. 6, Jun. 1995, '95 Conference on PLDI | |
97 | ||
98 | Global code motion / global value numbering | |
99 | C. Click | |
100 | ACM SIGPLAN Notices Vol. 30, Num. 6, Jun. 1995, '95 Conference on PLDI | |
101 | ||
102 | Value Driven Redundancy Elimination | |
103 | L.T. Simpson | |
104 | Rice University Ph.D. thesis, Apr. 1996 | |
105 | ||
106 | Value Numbering | |
107 | L.T. Simpson | |
108 | Massively Scalar Compiler Project, Rice University, Sep. 1996 | |
109 | ||
110 | High Performance Compilers for Parallel Computing | |
111 | Michael Wolfe | |
112 | Addison-Wesley, 1996 | |
113 | ||
f4e584dc JL |
114 | Advanced Compiler Design and Implementation |
115 | Steven Muchnick | |
116 | Morgan Kaufmann, 1997 | |
117 | ||
a42cd965 AM |
118 | Building an Optimizing Compiler |
119 | Robert Morgan | |
120 | Digital Press, 1998 | |
121 | ||
f4e584dc JL |
122 | People wishing to speed up the code here should read: |
123 | Elimination Algorithms for Data Flow Analysis | |
124 | B.G. Ryder, M.C. Paull | |
125 | ACM Computing Surveys, Vol. 18, Num. 3, Sep. 1986 | |
126 | ||
127 | How to Analyze Large Programs Efficiently and Informatively | |
128 | D.M. Dhamdhere, B.K. Rosen, F.K. Zadeck | |
129 | ACM SIGPLAN Notices Vol. 27, Num. 7, Jul. 1992, '92 Conference on PLDI | |
130 | ||
7506f491 DE |
131 | People wishing to do something different can find various possibilities |
132 | in the above papers and elsewhere. | |
133 | */ | |
134 | ||
135 | #include "config.h" | |
50b2596f | 136 | #include "system.h" |
4977bab6 ZW |
137 | #include "coretypes.h" |
138 | #include "tm.h" | |
718f9c0f | 139 | #include "diagnostic-core.h" |
01198c2f | 140 | #include "toplev.h" |
7506f491 | 141 | |
b11f0116 | 142 | #include "hard-reg-set.h" |
7506f491 | 143 | #include "rtl.h" |
b0656d8b | 144 | #include "tree.h" |
6baf1cc8 | 145 | #include "tm_p.h" |
7506f491 | 146 | #include "regs.h" |
b11f0116 | 147 | #include "ira.h" |
7506f491 | 148 | #include "flags.h" |
7506f491 DE |
149 | #include "insn-config.h" |
150 | #include "recog.h" | |
151 | #include "basic-block.h" | |
49ad7cfa | 152 | #include "function.h" |
589005ff | 153 | #include "expr.h" |
e7d482b9 | 154 | #include "except.h" |
fb0c0a12 | 155 | #include "ggc.h" |
f1fa37ff | 156 | #include "params.h" |
ae860ff7 | 157 | #include "cselib.h" |
d128effb | 158 | #include "intl.h" |
7506f491 | 159 | #include "obstack.h" |
ef330312 | 160 | #include "tree-pass.h" |
4a8fb1a1 | 161 | #include "hash-table.h" |
6fb5fa3c DB |
162 | #include "df.h" |
163 | #include "dbgcnt.h" | |
ec0a1343 | 164 | #include "target.h" |
7c6811fe | 165 | #include "gcse.h" |
4fa31c2a | 166 | |
f4e584dc | 167 | /* We support GCSE via Partial Redundancy Elimination. PRE optimizations |
4cad6dba | 168 | are a superset of those done by classic GCSE. |
7506f491 | 169 | |
e45425ec SB |
170 | Two passes of copy/constant propagation are done around PRE or hoisting |
171 | because the first one enables more GCSE and the second one helps to clean | |
172 | up the copies that PRE and HOIST create. This is needed more for PRE than | |
173 | for HOIST because code hoisting will try to use an existing register | |
174 | containing the common subexpression rather than create a new one. This is | |
175 | harder to do for PRE because of the code motion (which HOIST doesn't do). | |
7506f491 DE |
176 | |
177 | Expressions we are interested in GCSE-ing are of the form | |
178 | (set (pseudo-reg) (expression)). | |
179 | Function want_to_gcse_p says what these are. | |
180 | ||
4cad6dba | 181 | In addition, expressions in REG_EQUAL notes are candidates for GCSE-ing. |
3906a4a1 | 182 | This allows PRE to hoist expressions that are expressed in multiple insns, |
4cad6dba SB |
183 | such as complex address calculations (e.g. for PIC code, or loads with a |
184 | high part and a low part). | |
3906a4a1 | 185 | |
7506f491 | 186 | PRE handles moving invariant expressions out of loops (by treating them as |
f4e584dc | 187 | partially redundant). |
7506f491 | 188 | |
7506f491 DE |
189 | ********************** |
190 | ||
191 | We used to support multiple passes but there are diminishing returns in | |
192 | doing so. The first pass usually makes 90% of the changes that are doable. | |
193 | A second pass can make a few more changes made possible by the first pass. | |
194 | Experiments show any further passes don't make enough changes to justify | |
195 | the expense. | |
196 | ||
197 | A study of spec92 using an unlimited number of passes: | |
198 | [1 pass] = 1208 substitutions, [2] = 577, [3] = 202, [4] = 192, [5] = 83, | |
199 | [6] = 34, [7] = 17, [8] = 9, [9] = 4, [10] = 4, [11] = 2, | |
200 | [12] = 2, [13] = 1, [15] = 1, [16] = 2, [41] = 1 | |
201 | ||
202 | It was found doing copy propagation between each pass enables further | |
203 | substitutions. | |
204 | ||
3906a4a1 SB |
205 | This study was done before expressions in REG_EQUAL notes were added as |
206 | candidate expressions for optimization, and before the GIMPLE optimizers | |
207 | were added. Probably, multiple passes is even less efficient now than | |
208 | at the time when the study was conducted. | |
209 | ||
7506f491 | 210 | PRE is quite expensive in complicated functions because the DFA can take |
3906a4a1 | 211 | a while to converge. Hence we only perform one pass. |
7506f491 DE |
212 | |
213 | ********************** | |
214 | ||
215 | The steps for PRE are: | |
216 | ||
217 | 1) Build the hash table of expressions we wish to GCSE (expr_hash_table). | |
218 | ||
219 | 2) Perform the data flow analysis for PRE. | |
220 | ||
221 | 3) Delete the redundant instructions | |
222 | ||
223 | 4) Insert the required copies [if any] that make the partially | |
224 | redundant instructions fully redundant. | |
225 | ||
226 | 5) For other reaching expressions, insert an instruction to copy the value | |
227 | to a newly created pseudo that will reach the redundant instruction. | |
228 | ||
229 | The deletion is done first so that when we do insertions we | |
230 | know which pseudo reg to use. | |
231 | ||
232 | Various papers have argued that PRE DFA is expensive (O(n^2)) and others | |
233 | argue it is not. The number of iterations for the algorithm to converge | |
234 | is typically 2-4 so I don't view it as that expensive (relatively speaking). | |
235 | ||
4cad6dba | 236 | PRE GCSE depends heavily on the second CPROP pass to clean up the copies |
7506f491 DE |
237 | we create. To make an expression reach the place where it's redundant, |
238 | the result of the expression is copied to a new register, and the redundant | |
239 | expression is deleted by replacing it with this new register. Classic GCSE | |
240 | doesn't have this problem as much as it computes the reaching defs of | |
a3c28ba2 KH |
241 | each register in each block and thus can try to use an existing |
242 | register. */ | |
7506f491 DE |
243 | \f |
244 | /* GCSE global vars. */ | |
245 | ||
7c6811fe RS |
246 | struct target_gcse default_target_gcse; |
247 | #if SWITCHABLE_TARGET | |
248 | struct target_gcse *this_target_gcse = &default_target_gcse; | |
249 | #endif | |
250 | ||
5f39ad47 SB |
251 | /* Set to non-zero if CSE should run after all GCSE optimizations are done. */ |
252 | int flag_rerun_cse_after_global_opts; | |
f4e584dc | 253 | |
7506f491 DE |
254 | /* An obstack for our working variables. */ |
255 | static struct obstack gcse_obstack; | |
256 | ||
7506f491 DE |
257 | /* Hash table of expressions. */ |
258 | ||
259 | struct expr | |
260 | { | |
43c8a043 | 261 | /* The expression. */ |
7506f491 DE |
262 | rtx expr; |
263 | /* Index in the available expression bitmaps. */ | |
264 | int bitmap_index; | |
265 | /* Next entry with the same hash. */ | |
266 | struct expr *next_same_hash; | |
267 | /* List of anticipatable occurrences in basic blocks in the function. | |
268 | An "anticipatable occurrence" is one that is the first occurrence in the | |
f4e584dc JL |
269 | basic block, the operands are not modified in the basic block prior |
270 | to the occurrence and the output is not used between the start of | |
271 | the block and the occurrence. */ | |
7506f491 DE |
272 | struct occr *antic_occr; |
273 | /* List of available occurrence in basic blocks in the function. | |
274 | An "available occurrence" is one that is the last occurrence in the | |
275 | basic block and the operands are not modified by following statements in | |
276 | the basic block [including this insn]. */ | |
277 | struct occr *avail_occr; | |
278 | /* Non-null if the computation is PRE redundant. | |
279 | The value is the newly created pseudo-reg to record a copy of the | |
280 | expression in all the places that reach the redundant copy. */ | |
281 | rtx reaching_reg; | |
20160347 MK |
282 | /* Maximum distance in instructions this expression can travel. |
283 | We avoid moving simple expressions for more than a few instructions | |
284 | to keep register pressure under control. | |
285 | A value of "0" removes restrictions on how far the expression can | |
286 | travel. */ | |
287 | int max_distance; | |
7506f491 DE |
288 | }; |
289 | ||
290 | /* Occurrence of an expression. | |
291 | There is one per basic block. If a pattern appears more than once the | |
292 | last appearance is used [or first for anticipatable expressions]. */ | |
293 | ||
294 | struct occr | |
295 | { | |
296 | /* Next occurrence of this expression. */ | |
297 | struct occr *next; | |
298 | /* The insn that computes the expression. */ | |
299 | rtx insn; | |
cc2902df | 300 | /* Nonzero if this [anticipatable] occurrence has been deleted. */ |
7506f491 | 301 | char deleted_p; |
cc2902df | 302 | /* Nonzero if this [available] occurrence has been copied to |
7506f491 DE |
303 | reaching_reg. */ |
304 | /* ??? This is mutually exclusive with deleted_p, so they could share | |
305 | the same byte. */ | |
306 | char copied_p; | |
307 | }; | |
308 | ||
cad9aa15 | 309 | typedef struct occr *occr_t; |
cad9aa15 | 310 | |
e45425ec | 311 | /* Expression hash tables. |
7506f491 DE |
312 | Each hash table is an array of buckets. |
313 | ??? It is known that if it were an array of entries, structure elements | |
314 | `next_same_hash' and `bitmap_index' wouldn't be necessary. However, it is | |
315 | not clear whether in the final analysis a sufficient amount of memory would | |
316 | be saved as the size of the available expression bitmaps would be larger | |
317 | [one could build a mapping table without holes afterwards though]. | |
c4c81601 | 318 | Someday I'll perform the computation and figure it out. */ |
7506f491 | 319 | |
7e5487a2 | 320 | struct hash_table_d |
02280659 ZD |
321 | { |
322 | /* The table itself. | |
323 | This is an array of `expr_hash_table_size' elements. */ | |
324 | struct expr **table; | |
325 | ||
326 | /* Size of the hash table, in elements. */ | |
327 | unsigned int size; | |
2e653e39 | 328 | |
02280659 ZD |
329 | /* Number of hash table elements. */ |
330 | unsigned int n_elems; | |
02280659 | 331 | }; |
c4c81601 | 332 | |
02280659 | 333 | /* Expression hash table. */ |
7e5487a2 | 334 | static struct hash_table_d expr_hash_table; |
02280659 | 335 | |
a13d4ebf | 336 | /* This is a list of expressions which are MEMs and will be used by load |
589005ff | 337 | or store motion. |
43c8a043 EB |
338 | Load motion tracks MEMs which aren't killed by anything except itself, |
339 | i.e. loads and stores to a single location. | |
589005ff | 340 | We can then allow movement of these MEM refs with a little special |
a13d4ebf AM |
341 | allowance. (all stores copy the same value to the reaching reg used |
342 | for the loads). This means all values used to store into memory must have | |
43c8a043 | 343 | no side effects so we can re-issue the setter value. */ |
a13d4ebf AM |
344 | |
345 | struct ls_expr | |
346 | { | |
347 | struct expr * expr; /* Gcse expression reference for LM. */ | |
348 | rtx pattern; /* Pattern of this mem. */ | |
47a3dae1 | 349 | rtx pattern_regs; /* List of registers mentioned by the mem. */ |
aaa4ca30 AJ |
350 | rtx loads; /* INSN list of loads seen. */ |
351 | rtx stores; /* INSN list of stores seen. */ | |
a13d4ebf AM |
352 | struct ls_expr * next; /* Next in the list. */ |
353 | int invalid; /* Invalid for some reason. */ | |
354 | int index; /* If it maps to a bitmap index. */ | |
b58b21d5 | 355 | unsigned int hash_index; /* Index when in a hash table. */ |
a13d4ebf AM |
356 | rtx reaching_reg; /* Register to use when re-writing. */ |
357 | }; | |
358 | ||
359 | /* Head of the list of load/store memory refs. */ | |
360 | static struct ls_expr * pre_ldst_mems = NULL; | |
361 | ||
4a8fb1a1 LC |
362 | struct pre_ldst_expr_hasher : typed_noop_remove <ls_expr> |
363 | { | |
364 | typedef ls_expr value_type; | |
365 | typedef value_type compare_type; | |
366 | static inline hashval_t hash (const value_type *); | |
367 | static inline bool equal (const value_type *, const compare_type *); | |
368 | }; | |
369 | ||
370 | /* Hashtable helpers. */ | |
371 | inline hashval_t | |
372 | pre_ldst_expr_hasher::hash (const value_type *x) | |
373 | { | |
374 | int do_not_record_p = 0; | |
375 | return | |
376 | hash_rtx (x->pattern, GET_MODE (x->pattern), &do_not_record_p, NULL, false); | |
377 | } | |
378 | ||
379 | static int expr_equiv_p (const_rtx, const_rtx); | |
380 | ||
381 | inline bool | |
382 | pre_ldst_expr_hasher::equal (const value_type *ptr1, | |
383 | const compare_type *ptr2) | |
384 | { | |
385 | return expr_equiv_p (ptr1->pattern, ptr2->pattern); | |
386 | } | |
387 | ||
9727e468 | 388 | /* Hashtable for the load/store memory refs. */ |
4a8fb1a1 | 389 | static hash_table <pre_ldst_expr_hasher> pre_ldst_table; |
9727e468 | 390 | |
7506f491 DE |
391 | /* Bitmap containing one bit for each register in the program. |
392 | Used when performing GCSE to track which registers have been set since | |
393 | the start of the basic block. */ | |
73991d6a | 394 | static regset reg_set_bitmap; |
7506f491 | 395 | |
a13d4ebf AM |
396 | /* Array, indexed by basic block number for a list of insns which modify |
397 | memory within that block. */ | |
9771b263 | 398 | static vec<rtx> *modify_mem_list; |
0516f6fe | 399 | static bitmap modify_mem_list_set; |
a13d4ebf | 400 | |
6ce1edcf NF |
401 | typedef struct modify_pair_s |
402 | { | |
403 | rtx dest; /* A MEM. */ | |
404 | rtx dest_addr; /* The canonical address of `dest'. */ | |
405 | } modify_pair; | |
406 | ||
6ce1edcf NF |
407 | |
408 | /* This array parallels modify_mem_list, except that it stores MEMs | |
409 | being set and their canonicalized memory addresses. */ | |
9771b263 | 410 | static vec<modify_pair> *canon_modify_mem_list; |
0516f6fe | 411 | |
aa47fcfa JL |
412 | /* Bitmap indexed by block numbers to record which blocks contain |
413 | function calls. */ | |
414 | static bitmap blocks_with_calls; | |
415 | ||
7506f491 DE |
416 | /* Various variables for statistics gathering. */ |
417 | ||
418 | /* Memory used in a pass. | |
419 | This isn't intended to be absolutely precise. Its intent is only | |
420 | to keep an eye on memory usage. */ | |
421 | static int bytes_used; | |
c4c81601 | 422 | |
7506f491 DE |
423 | /* GCSE substitutions made. */ |
424 | static int gcse_subst_count; | |
425 | /* Number of copy instructions created. */ | |
426 | static int gcse_create_count; | |
7506f491 | 427 | \f |
20160347 MK |
428 | /* Doing code hoisting. */ |
429 | static bool doing_code_hoisting_p = false; | |
430 | \f | |
e83f4801 | 431 | /* For available exprs */ |
df35c271 | 432 | static sbitmap *ae_kill; |
7506f491 | 433 | \f |
b11f0116 BC |
434 | /* Data stored for each basic block. */ |
435 | struct bb_data | |
436 | { | |
437 | /* Maximal register pressure inside basic block for given register class | |
438 | (defined only for the pressure classes). */ | |
439 | int max_reg_pressure[N_REG_CLASSES]; | |
4b8181c5 BC |
440 | /* Recorded register pressure of basic block before trying to hoist |
441 | an expression. Will be used to restore the register pressure | |
442 | if the expression should not be hoisted. */ | |
443 | int old_pressure; | |
444 | /* Recorded register live_in info of basic block during code hoisting | |
445 | process. BACKUP is used to record live_in info before trying to | |
446 | hoist an expression, and will be used to restore LIVE_IN if the | |
447 | expression should not be hoisted. */ | |
448 | bitmap live_in, backup; | |
b11f0116 BC |
449 | }; |
450 | ||
451 | #define BB_DATA(bb) ((struct bb_data *) (bb)->aux) | |
452 | ||
453 | static basic_block curr_bb; | |
454 | ||
455 | /* Current register pressure for each pressure class. */ | |
456 | static int curr_reg_pressure[N_REG_CLASSES]; | |
457 | \f | |
458 | ||
1d088dee | 459 | static void compute_can_copy (void); |
9fe15a12 KG |
460 | static void *gmalloc (size_t) ATTRIBUTE_MALLOC; |
461 | static void *gcalloc (size_t, size_t) ATTRIBUTE_MALLOC; | |
703ad42b | 462 | static void *gcse_alloc (unsigned long); |
eb232f4e | 463 | static void alloc_gcse_mem (void); |
1d088dee | 464 | static void free_gcse_mem (void); |
7e5487a2 ILT |
465 | static void hash_scan_insn (rtx, struct hash_table_d *); |
466 | static void hash_scan_set (rtx, rtx, struct hash_table_d *); | |
467 | static void hash_scan_clobber (rtx, rtx, struct hash_table_d *); | |
468 | static void hash_scan_call (rtx, rtx, struct hash_table_d *); | |
20160347 | 469 | static int want_to_gcse_p (rtx, int *); |
ed7a4b4b KG |
470 | static int oprs_unchanged_p (const_rtx, const_rtx, int); |
471 | static int oprs_anticipatable_p (const_rtx, const_rtx); | |
472 | static int oprs_available_p (const_rtx, const_rtx); | |
20160347 | 473 | static void insert_expr_in_table (rtx, enum machine_mode, rtx, int, int, int, |
7e5487a2 | 474 | struct hash_table_d *); |
ed7a4b4b | 475 | static unsigned int hash_expr (const_rtx, enum machine_mode, int *, int); |
1d088dee AJ |
476 | static void record_last_reg_set_info (rtx, int); |
477 | static void record_last_mem_set_info (rtx); | |
7bc980e1 | 478 | static void record_last_set_info (rtx, const_rtx, void *); |
7e5487a2 | 479 | static void compute_hash_table (struct hash_table_d *); |
e45425ec | 480 | static void alloc_hash_table (struct hash_table_d *); |
7e5487a2 ILT |
481 | static void free_hash_table (struct hash_table_d *); |
482 | static void compute_hash_table_work (struct hash_table_d *); | |
483 | static void dump_hash_table (FILE *, const char *, struct hash_table_d *); | |
e45425ec | 484 | static void compute_transp (const_rtx, int, sbitmap *); |
1d088dee | 485 | static void compute_local_properties (sbitmap *, sbitmap *, sbitmap *, |
7e5487a2 | 486 | struct hash_table_d *); |
7bc980e1 | 487 | static void mems_conflict_for_gcse_p (rtx, const_rtx, void *); |
ed7a4b4b | 488 | static int load_killed_in_block_p (const_basic_block, int, const_rtx, int); |
7bc980e1 | 489 | static void canon_list_insert (rtx, const_rtx, void *); |
1d088dee AJ |
490 | static void alloc_pre_mem (int, int); |
491 | static void free_pre_mem (void); | |
43c8a043 | 492 | static struct edge_list *compute_pre_data (void); |
1d088dee AJ |
493 | static int pre_expr_reaches_here_p (basic_block, struct expr *, |
494 | basic_block); | |
eae7938e | 495 | static void insert_insn_end_basic_block (struct expr *, basic_block); |
1d088dee AJ |
496 | static void pre_insert_copy_insn (struct expr *, rtx); |
497 | static void pre_insert_copies (void); | |
498 | static int pre_delete (void); | |
43c8a043 | 499 | static int pre_gcse (struct edge_list *); |
5f39ad47 | 500 | static int one_pre_gcse_pass (void); |
1d088dee AJ |
501 | static void add_label_notes (rtx, rtx); |
502 | static void alloc_code_hoist_mem (int, int); | |
503 | static void free_code_hoist_mem (void); | |
504 | static void compute_code_hoist_vbeinout (void); | |
505 | static void compute_code_hoist_data (void); | |
b11f0116 BC |
506 | static int should_hoist_expr_to_dom (basic_block, struct expr *, basic_block, |
507 | sbitmap, int, int *, enum reg_class, | |
4b8181c5 | 508 | int *, bitmap, rtx); |
5f39ad47 | 509 | static int hoist_code (void); |
4b8181c5 | 510 | static enum reg_class get_regno_pressure_class (int regno, int *nregs); |
b11f0116 | 511 | static enum reg_class get_pressure_class_and_nregs (rtx insn, int *nregs); |
1d088dee | 512 | static int one_code_hoisting_pass (void); |
1d088dee AJ |
513 | static rtx process_insert_insn (struct expr *); |
514 | static int pre_edge_insert (struct edge_list *, struct expr **); | |
1d088dee AJ |
515 | static int pre_expr_reaches_here_p_work (basic_block, struct expr *, |
516 | basic_block, char *); | |
517 | static struct ls_expr * ldst_entry (rtx); | |
518 | static void free_ldst_entry (struct ls_expr *); | |
43c8a043 | 519 | static void free_ld_motion_mems (void); |
1d088dee AJ |
520 | static void print_ldst_list (FILE *); |
521 | static struct ls_expr * find_rtx_in_ldst (rtx); | |
ed7a4b4b | 522 | static int simple_mem (const_rtx); |
1d088dee AJ |
523 | static void invalidate_any_buried_refs (rtx); |
524 | static void compute_ld_motion_mems (void); | |
525 | static void trim_ld_motion_mems (void); | |
526 | static void update_ld_motion_stores (struct expr *); | |
1d088dee AJ |
527 | static void clear_modify_mem_tables (void); |
528 | static void free_modify_mem_tables (void); | |
529 | static rtx gcse_emit_move_after (rtx, rtx, rtx); | |
d128effb | 530 | static bool is_too_expensive (const char *); |
1b4572a8 KG |
531 | |
532 | #define GNEW(T) ((T *) gmalloc (sizeof (T))) | |
533 | #define GCNEW(T) ((T *) gcalloc (1, sizeof (T))) | |
534 | ||
535 | #define GNEWVEC(T, N) ((T *) gmalloc (sizeof (T) * (N))) | |
536 | #define GCNEWVEC(T, N) ((T *) gcalloc ((N), sizeof (T))) | |
1b4572a8 KG |
537 | |
538 | #define GNEWVAR(T, S) ((T *) gmalloc ((S))) | |
539 | #define GCNEWVAR(T, S) ((T *) gcalloc (1, (S))) | |
1b4572a8 KG |
540 | |
541 | #define GOBNEW(T) ((T *) gcse_alloc (sizeof (T))) | |
542 | #define GOBNEWVAR(T, S) ((T *) gcse_alloc ((S))) | |
7506f491 | 543 | \f |
7506f491 DE |
544 | /* Misc. utilities. */ |
545 | ||
7c6811fe RS |
546 | #define can_copy \ |
547 | (this_target_gcse->x_can_copy) | |
548 | #define can_copy_init_p \ | |
549 | (this_target_gcse->x_can_copy_init_p) | |
773eae39 | 550 | |
7506f491 DE |
551 | /* Compute which modes support reg/reg copy operations. */ |
552 | ||
553 | static void | |
1d088dee | 554 | compute_can_copy (void) |
7506f491 DE |
555 | { |
556 | int i; | |
50b2596f | 557 | #ifndef AVOID_CCMODE_COPIES |
8e42ace1 | 558 | rtx reg, insn; |
50b2596f | 559 | #endif |
773eae39 | 560 | memset (can_copy, 0, NUM_MACHINE_MODES); |
7506f491 DE |
561 | |
562 | start_sequence (); | |
563 | for (i = 0; i < NUM_MACHINE_MODES; i++) | |
c4c81601 RK |
564 | if (GET_MODE_CLASS (i) == MODE_CC) |
565 | { | |
7506f491 | 566 | #ifdef AVOID_CCMODE_COPIES |
773eae39 | 567 | can_copy[i] = 0; |
7506f491 | 568 | #else |
c4c81601 RK |
569 | reg = gen_rtx_REG ((enum machine_mode) i, LAST_VIRTUAL_REGISTER + 1); |
570 | insn = emit_insn (gen_rtx_SET (VOIDmode, reg, reg)); | |
9714cf43 | 571 | if (recog (PATTERN (insn), insn, NULL) >= 0) |
773eae39 | 572 | can_copy[i] = 1; |
7506f491 | 573 | #endif |
c4c81601 | 574 | } |
141b5810 | 575 | else |
773eae39 | 576 | can_copy[i] = 1; |
c4c81601 | 577 | |
7506f491 | 578 | end_sequence (); |
7506f491 | 579 | } |
773eae39 EB |
580 | |
581 | /* Returns whether the mode supports reg/reg copy operations. */ | |
582 | ||
583 | bool | |
1d088dee | 584 | can_copy_p (enum machine_mode mode) |
773eae39 | 585 | { |
773eae39 EB |
586 | if (! can_copy_init_p) |
587 | { | |
588 | compute_can_copy (); | |
589 | can_copy_init_p = true; | |
590 | } | |
591 | ||
592 | return can_copy[mode] != 0; | |
593 | } | |
7506f491 DE |
594 | \f |
595 | /* Cover function to xmalloc to record bytes allocated. */ | |
596 | ||
703ad42b | 597 | static void * |
4ac11022 | 598 | gmalloc (size_t size) |
7506f491 DE |
599 | { |
600 | bytes_used += size; | |
601 | return xmalloc (size); | |
602 | } | |
603 | ||
9fe15a12 KG |
604 | /* Cover function to xcalloc to record bytes allocated. */ |
605 | ||
606 | static void * | |
607 | gcalloc (size_t nelem, size_t elsize) | |
608 | { | |
609 | bytes_used += nelem * elsize; | |
610 | return xcalloc (nelem, elsize); | |
611 | } | |
612 | ||
77bbd421 | 613 | /* Cover function to obstack_alloc. */ |
7506f491 | 614 | |
703ad42b | 615 | static void * |
1d088dee | 616 | gcse_alloc (unsigned long size) |
7506f491 | 617 | { |
77bbd421 | 618 | bytes_used += size; |
703ad42b | 619 | return obstack_alloc (&gcse_obstack, size); |
7506f491 DE |
620 | } |
621 | ||
4a81774c | 622 | /* Allocate memory for the reg/memory set tracking tables. |
7506f491 DE |
623 | This is called at the start of each pass. */ |
624 | ||
625 | static void | |
eb232f4e | 626 | alloc_gcse_mem (void) |
7506f491 | 627 | { |
7506f491 | 628 | /* Allocate vars to track sets of regs. */ |
7a8cba34 | 629 | reg_set_bitmap = ALLOC_REG_SET (NULL); |
7506f491 | 630 | |
a13d4ebf | 631 | /* Allocate array to keep a list of insns which modify memory in each |
9771b263 DN |
632 | basic block. The two typedefs are needed to work around the |
633 | pre-processor limitation with template types in macro arguments. */ | |
634 | typedef vec<rtx> vec_rtx_heap; | |
635 | typedef vec<modify_pair> vec_modify_pair_heap; | |
636 | modify_mem_list = GCNEWVEC (vec_rtx_heap, last_basic_block); | |
637 | canon_modify_mem_list = GCNEWVEC (vec_modify_pair_heap, last_basic_block); | |
8bdbfff5 NS |
638 | modify_mem_list_set = BITMAP_ALLOC (NULL); |
639 | blocks_with_calls = BITMAP_ALLOC (NULL); | |
7506f491 DE |
640 | } |
641 | ||
642 | /* Free memory allocated by alloc_gcse_mem. */ | |
643 | ||
644 | static void | |
1d088dee | 645 | free_gcse_mem (void) |
7506f491 | 646 | { |
d5b8da97 SB |
647 | FREE_REG_SET (reg_set_bitmap); |
648 | ||
73991d6a | 649 | free_modify_mem_tables (); |
8bdbfff5 NS |
650 | BITMAP_FREE (modify_mem_list_set); |
651 | BITMAP_FREE (blocks_with_calls); | |
7506f491 | 652 | } |
b5ce41ff JL |
653 | \f |
654 | /* Compute the local properties of each recorded expression. | |
c4c81601 RK |
655 | |
656 | Local properties are those that are defined by the block, irrespective of | |
657 | other blocks. | |
b5ce41ff JL |
658 | |
659 | An expression is transparent in a block if its operands are not modified | |
660 | in the block. | |
661 | ||
662 | An expression is computed (locally available) in a block if it is computed | |
663 | at least once and expression would contain the same value if the | |
664 | computation was moved to the end of the block. | |
665 | ||
666 | An expression is locally anticipatable in a block if it is computed at | |
667 | least once and expression would contain the same value if the computation | |
668 | was moved to the beginning of the block. | |
669 | ||
e45425ec | 670 | We call this routine for pre and code hoisting. They all compute |
c4c81601 | 671 | basically the same information and thus can easily share this code. |
7506f491 | 672 | |
c4c81601 RK |
673 | TRANSP, COMP, and ANTLOC are destination sbitmaps for recording local |
674 | properties. If NULL, then it is not necessary to compute or record that | |
675 | particular property. | |
b5ce41ff | 676 | |
e45425ec | 677 | TABLE controls which hash table to look at. */ |
589005ff | 678 | |
b5ce41ff | 679 | static void |
7b1b4aed | 680 | compute_local_properties (sbitmap *transp, sbitmap *comp, sbitmap *antloc, |
7e5487a2 | 681 | struct hash_table_d *table) |
b5ce41ff | 682 | { |
02280659 | 683 | unsigned int i; |
589005ff | 684 | |
b5ce41ff JL |
685 | /* Initialize any bitmaps that were passed in. */ |
686 | if (transp) | |
695ab36a | 687 | { |
f61e445a | 688 | bitmap_vector_ones (transp, last_basic_block); |
695ab36a | 689 | } |
c4c81601 | 690 | |
b5ce41ff | 691 | if (comp) |
f61e445a | 692 | bitmap_vector_clear (comp, last_basic_block); |
b5ce41ff | 693 | if (antloc) |
f61e445a | 694 | bitmap_vector_clear (antloc, last_basic_block); |
b5ce41ff | 695 | |
02280659 | 696 | for (i = 0; i < table->size; i++) |
7506f491 | 697 | { |
b5ce41ff JL |
698 | struct expr *expr; |
699 | ||
02280659 | 700 | for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash) |
b5ce41ff | 701 | { |
b5ce41ff | 702 | int indx = expr->bitmap_index; |
c4c81601 | 703 | struct occr *occr; |
b5ce41ff JL |
704 | |
705 | /* The expression is transparent in this block if it is not killed. | |
706 | We start by assuming all are transparent [none are killed], and | |
707 | then reset the bits for those that are. */ | |
b5ce41ff | 708 | if (transp) |
e45425ec | 709 | compute_transp (expr->expr, indx, transp); |
b5ce41ff JL |
710 | |
711 | /* The occurrences recorded in antic_occr are exactly those that | |
cc2902df | 712 | we want to set to nonzero in ANTLOC. */ |
b5ce41ff | 713 | if (antloc) |
c4c81601 RK |
714 | for (occr = expr->antic_occr; occr != NULL; occr = occr->next) |
715 | { | |
d7c028c0 | 716 | bitmap_set_bit (antloc[BLOCK_FOR_INSN (occr->insn)->index], indx); |
b5ce41ff | 717 | |
c4c81601 RK |
718 | /* While we're scanning the table, this is a good place to |
719 | initialize this. */ | |
720 | occr->deleted_p = 0; | |
721 | } | |
b5ce41ff JL |
722 | |
723 | /* The occurrences recorded in avail_occr are exactly those that | |
cc2902df | 724 | we want to set to nonzero in COMP. */ |
b5ce41ff | 725 | if (comp) |
c4c81601 RK |
726 | for (occr = expr->avail_occr; occr != NULL; occr = occr->next) |
727 | { | |
d7c028c0 | 728 | bitmap_set_bit (comp[BLOCK_FOR_INSN (occr->insn)->index], indx); |
b5ce41ff | 729 | |
c4c81601 RK |
730 | /* While we're scanning the table, this is a good place to |
731 | initialize this. */ | |
732 | occr->copied_p = 0; | |
733 | } | |
b5ce41ff JL |
734 | |
735 | /* While we're scanning the table, this is a good place to | |
736 | initialize this. */ | |
737 | expr->reaching_reg = 0; | |
738 | } | |
7506f491 | 739 | } |
7506f491 DE |
740 | } |
741 | \f | |
7506f491 DE |
742 | /* Hash table support. */ |
743 | ||
80c29cc4 RZ |
744 | struct reg_avail_info |
745 | { | |
e0082a72 | 746 | basic_block last_bb; |
80c29cc4 RZ |
747 | int first_set; |
748 | int last_set; | |
749 | }; | |
750 | ||
751 | static struct reg_avail_info *reg_avail_info; | |
e0082a72 | 752 | static basic_block current_bb; |
7506f491 | 753 | |
fb0c0a12 RK |
754 | /* See whether X, the source of a set, is something we want to consider for |
755 | GCSE. */ | |
7506f491 DE |
756 | |
757 | static int | |
20160347 | 758 | want_to_gcse_p (rtx x, int *max_distance_ptr) |
7506f491 | 759 | { |
3d8504ac RS |
760 | #ifdef STACK_REGS |
761 | /* On register stack architectures, don't GCSE constants from the | |
762 | constant pool, as the benefits are often swamped by the overhead | |
763 | of shuffling the register stack between basic blocks. */ | |
764 | if (IS_STACK_MODE (GET_MODE (x))) | |
765 | x = avoid_constant_pool_reference (x); | |
766 | #endif | |
767 | ||
20160347 MK |
768 | /* GCSE'ing constants: |
769 | ||
770 | We do not specifically distinguish between constant and non-constant | |
5e8f01f4 | 771 | expressions in PRE and Hoist. We use set_src_cost below to limit |
20160347 MK |
772 | the maximum distance simple expressions can travel. |
773 | ||
774 | Nevertheless, constants are much easier to GCSE, and, hence, | |
775 | it is easy to overdo the optimizations. Usually, excessive PRE and | |
776 | Hoisting of constant leads to increased register pressure. | |
777 | ||
778 | RA can deal with this by rematerialing some of the constants. | |
779 | Therefore, it is important that the back-end generates sets of constants | |
780 | in a way that allows reload rematerialize them under high register | |
781 | pressure, i.e., a pseudo register with REG_EQUAL to constant | |
782 | is set only once. Failing to do so will result in IRA/reload | |
783 | spilling such constants under high register pressure instead of | |
784 | rematerializing them. */ | |
785 | ||
c4c81601 | 786 | switch (GET_CODE (x)) |
7506f491 DE |
787 | { |
788 | case REG: | |
789 | case SUBREG: | |
20160347 MK |
790 | case CALL: |
791 | return 0; | |
792 | ||
d8116890 | 793 | CASE_CONST_ANY: |
20160347 MK |
794 | if (!doing_code_hoisting_p) |
795 | /* Do not PRE constants. */ | |
796 | return 0; | |
797 | ||
798 | /* FALLTHRU */ | |
7506f491 DE |
799 | |
800 | default: | |
20160347 MK |
801 | if (doing_code_hoisting_p) |
802 | /* PRE doesn't implement max_distance restriction. */ | |
803 | { | |
804 | int cost; | |
805 | int max_distance; | |
806 | ||
807 | gcc_assert (!optimize_function_for_speed_p (cfun) | |
808 | && optimize_function_for_size_p (cfun)); | |
5e8f01f4 | 809 | cost = set_src_cost (x, 0); |
20160347 MK |
810 | |
811 | if (cost < COSTS_N_INSNS (GCSE_UNRESTRICTED_COST)) | |
812 | { | |
813 | max_distance = (GCSE_COST_DISTANCE_RATIO * cost) / 10; | |
814 | if (max_distance == 0) | |
815 | return 0; | |
816 | ||
817 | gcc_assert (max_distance > 0); | |
818 | } | |
819 | else | |
820 | max_distance = 0; | |
821 | ||
822 | if (max_distance_ptr) | |
823 | *max_distance_ptr = max_distance; | |
824 | } | |
825 | ||
df35c271 | 826 | return can_assign_to_reg_without_clobbers_p (x); |
7506f491 | 827 | } |
1707bafa RS |
828 | } |
829 | ||
df35c271 | 830 | /* Used internally by can_assign_to_reg_without_clobbers_p. */ |
1707bafa RS |
831 | |
832 | static GTY(()) rtx test_insn; | |
833 | ||
df35c271 SB |
834 | /* Return true if we can assign X to a pseudo register such that the |
835 | resulting insn does not result in clobbering a hard register as a | |
836 | side-effect. | |
ec0a1343 JB |
837 | |
838 | Additionally, if the target requires it, check that the resulting insn | |
839 | can be copied. If it cannot, this means that X is special and probably | |
840 | has hidden side-effects we don't want to mess with. | |
841 | ||
df35c271 SB |
842 | This function is typically used by code motion passes, to verify |
843 | that it is safe to insert an insn without worrying about clobbering | |
844 | maybe live hard regs. */ | |
1707bafa | 845 | |
df35c271 SB |
846 | bool |
847 | can_assign_to_reg_without_clobbers_p (rtx x) | |
1707bafa RS |
848 | { |
849 | int num_clobbers = 0; | |
850 | int icode; | |
7506f491 | 851 | |
fb0c0a12 RK |
852 | /* If this is a valid operand, we are OK. If it's VOIDmode, we aren't. */ |
853 | if (general_operand (x, GET_MODE (x))) | |
854 | return 1; | |
855 | else if (GET_MODE (x) == VOIDmode) | |
856 | return 0; | |
857 | ||
858 | /* Otherwise, check if we can make a valid insn from it. First initialize | |
859 | our test insn if we haven't already. */ | |
860 | if (test_insn == 0) | |
861 | { | |
862 | test_insn | |
863 | = make_insn_raw (gen_rtx_SET (VOIDmode, | |
864 | gen_rtx_REG (word_mode, | |
865 | FIRST_PSEUDO_REGISTER * 2), | |
866 | const0_rtx)); | |
867 | NEXT_INSN (test_insn) = PREV_INSN (test_insn) = 0; | |
fb0c0a12 RK |
868 | } |
869 | ||
870 | /* Now make an insn like the one we would make when GCSE'ing and see if | |
871 | valid. */ | |
872 | PUT_MODE (SET_DEST (PATTERN (test_insn)), GET_MODE (x)); | |
873 | SET_SRC (PATTERN (test_insn)) = x; | |
b8698a0f | 874 | |
ec0a1343 JB |
875 | icode = recog (PATTERN (test_insn), test_insn, &num_clobbers); |
876 | if (icode < 0) | |
877 | return false; | |
b8698a0f | 878 | |
ec0a1343 JB |
879 | if (num_clobbers > 0 && added_clobbers_hard_reg_p (icode)) |
880 | return false; | |
b8698a0f | 881 | |
ec0a1343 JB |
882 | if (targetm.cannot_copy_insn_p && targetm.cannot_copy_insn_p (test_insn)) |
883 | return false; | |
b8698a0f | 884 | |
ec0a1343 | 885 | return true; |
7506f491 DE |
886 | } |
887 | ||
cc2902df | 888 | /* Return nonzero if the operands of expression X are unchanged from the |
7506f491 DE |
889 | start of INSN's basic block up to but not including INSN (if AVAIL_P == 0), |
890 | or from INSN to the end of INSN's basic block (if AVAIL_P != 0). */ | |
891 | ||
892 | static int | |
ed7a4b4b | 893 | oprs_unchanged_p (const_rtx x, const_rtx insn, int avail_p) |
7506f491 | 894 | { |
c4c81601 | 895 | int i, j; |
7506f491 | 896 | enum rtx_code code; |
6f7d635c | 897 | const char *fmt; |
7506f491 | 898 | |
7506f491 DE |
899 | if (x == 0) |
900 | return 1; | |
901 | ||
902 | code = GET_CODE (x); | |
903 | switch (code) | |
904 | { | |
905 | case REG: | |
80c29cc4 RZ |
906 | { |
907 | struct reg_avail_info *info = ®_avail_info[REGNO (x)]; | |
908 | ||
909 | if (info->last_bb != current_bb) | |
910 | return 1; | |
589005ff | 911 | if (avail_p) |
4a81774c | 912 | return info->last_set < DF_INSN_LUID (insn); |
80c29cc4 | 913 | else |
4a81774c | 914 | return info->first_set >= DF_INSN_LUID (insn); |
80c29cc4 | 915 | } |
7506f491 DE |
916 | |
917 | case MEM: | |
85c0f02d SB |
918 | if (! flag_gcse_lm |
919 | || load_killed_in_block_p (current_bb, DF_INSN_LUID (insn), | |
920 | x, avail_p)) | |
a13d4ebf | 921 | return 0; |
7506f491 | 922 | else |
c4c81601 | 923 | return oprs_unchanged_p (XEXP (x, 0), insn, avail_p); |
7506f491 DE |
924 | |
925 | case PRE_DEC: | |
926 | case PRE_INC: | |
927 | case POST_DEC: | |
928 | case POST_INC: | |
4b983fdc RH |
929 | case PRE_MODIFY: |
930 | case POST_MODIFY: | |
7506f491 DE |
931 | return 0; |
932 | ||
933 | case PC: | |
934 | case CC0: /*FIXME*/ | |
935 | case CONST: | |
d8116890 | 936 | CASE_CONST_ANY: |
7506f491 DE |
937 | case SYMBOL_REF: |
938 | case LABEL_REF: | |
939 | case ADDR_VEC: | |
940 | case ADDR_DIFF_VEC: | |
941 | return 1; | |
942 | ||
943 | default: | |
944 | break; | |
945 | } | |
946 | ||
c4c81601 | 947 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
7506f491 DE |
948 | { |
949 | if (fmt[i] == 'e') | |
950 | { | |
c4c81601 RK |
951 | /* If we are about to do the last recursive call needed at this |
952 | level, change it into iteration. This function is called enough | |
953 | to be worth it. */ | |
7506f491 | 954 | if (i == 0) |
c4c81601 RK |
955 | return oprs_unchanged_p (XEXP (x, i), insn, avail_p); |
956 | ||
957 | else if (! oprs_unchanged_p (XEXP (x, i), insn, avail_p)) | |
7506f491 DE |
958 | return 0; |
959 | } | |
960 | else if (fmt[i] == 'E') | |
c4c81601 RK |
961 | for (j = 0; j < XVECLEN (x, i); j++) |
962 | if (! oprs_unchanged_p (XVECEXP (x, i, j), insn, avail_p)) | |
963 | return 0; | |
7506f491 DE |
964 | } |
965 | ||
966 | return 1; | |
967 | } | |
968 | ||
43c8a043 | 969 | /* Info passed from load_killed_in_block_p to mems_conflict_for_gcse_p. */ |
a13d4ebf | 970 | |
43c8a043 EB |
971 | struct mem_conflict_info |
972 | { | |
973 | /* A memory reference for a load instruction, mems_conflict_for_gcse_p will | |
974 | see if a memory store conflicts with this memory load. */ | |
975 | const_rtx mem; | |
a13d4ebf | 976 | |
43c8a043 EB |
977 | /* True if mems_conflict_for_gcse_p finds a conflict between two memory |
978 | references. */ | |
979 | bool conflict; | |
980 | }; | |
981 | ||
982 | /* DEST is the output of an instruction. If it is a memory reference and | |
983 | possibly conflicts with the load found in DATA, then communicate this | |
984 | information back through DATA. */ | |
a13d4ebf AM |
985 | |
986 | static void | |
7bc980e1 | 987 | mems_conflict_for_gcse_p (rtx dest, const_rtx setter ATTRIBUTE_UNUSED, |
43c8a043 | 988 | void *data) |
a13d4ebf | 989 | { |
43c8a043 EB |
990 | struct mem_conflict_info *mci = (struct mem_conflict_info *) data; |
991 | ||
a13d4ebf AM |
992 | while (GET_CODE (dest) == SUBREG |
993 | || GET_CODE (dest) == ZERO_EXTRACT | |
a13d4ebf AM |
994 | || GET_CODE (dest) == STRICT_LOW_PART) |
995 | dest = XEXP (dest, 0); | |
996 | ||
997 | /* If DEST is not a MEM, then it will not conflict with the load. Note | |
998 | that function calls are assumed to clobber memory, but are handled | |
999 | elsewhere. */ | |
7b1b4aed | 1000 | if (! MEM_P (dest)) |
a13d4ebf | 1001 | return; |
aaa4ca30 | 1002 | |
a13d4ebf | 1003 | /* If we are setting a MEM in our list of specially recognized MEMs, |
589005ff | 1004 | don't mark as killed this time. */ |
43c8a043 | 1005 | if (pre_ldst_mems != NULL && expr_equiv_p (dest, mci->mem)) |
a13d4ebf AM |
1006 | { |
1007 | if (!find_rtx_in_ldst (dest)) | |
43c8a043 | 1008 | mci->conflict = true; |
a13d4ebf AM |
1009 | return; |
1010 | } | |
aaa4ca30 | 1011 | |
53d9622b | 1012 | if (true_dependence (dest, GET_MODE (dest), mci->mem)) |
43c8a043 | 1013 | mci->conflict = true; |
a13d4ebf AM |
1014 | } |
1015 | ||
1016 | /* Return nonzero if the expression in X (a memory reference) is killed | |
4a81774c | 1017 | in block BB before or after the insn with the LUID in UID_LIMIT. |
a13d4ebf AM |
1018 | AVAIL_P is nonzero for kills after UID_LIMIT, and zero for kills |
1019 | before UID_LIMIT. | |
1020 | ||
1021 | To check the entire block, set UID_LIMIT to max_uid + 1 and | |
1022 | AVAIL_P to 0. */ | |
1023 | ||
1024 | static int | |
43c8a043 EB |
1025 | load_killed_in_block_p (const_basic_block bb, int uid_limit, const_rtx x, |
1026 | int avail_p) | |
a13d4ebf | 1027 | { |
9771b263 | 1028 | vec<rtx> list = modify_mem_list[bb->index]; |
6409abe3 NF |
1029 | rtx setter; |
1030 | unsigned ix; | |
16c5b95d MH |
1031 | |
1032 | /* If this is a readonly then we aren't going to be changing it. */ | |
1033 | if (MEM_READONLY_P (x)) | |
1034 | return 0; | |
1035 | ||
9771b263 | 1036 | FOR_EACH_VEC_ELT_REVERSE (list, ix, setter) |
a13d4ebf | 1037 | { |
43c8a043 EB |
1038 | struct mem_conflict_info mci; |
1039 | ||
a13d4ebf AM |
1040 | /* Ignore entries in the list that do not apply. */ |
1041 | if ((avail_p | |
6409abe3 | 1042 | && DF_INSN_LUID (setter) < uid_limit) |
a13d4ebf | 1043 | || (! avail_p |
6409abe3 NF |
1044 | && DF_INSN_LUID (setter) > uid_limit)) |
1045 | continue; | |
a13d4ebf AM |
1046 | |
1047 | /* If SETTER is a call everything is clobbered. Note that calls | |
1048 | to pure functions are never put on the list, so we need not | |
1049 | worry about them. */ | |
7b1b4aed | 1050 | if (CALL_P (setter)) |
a13d4ebf AM |
1051 | return 1; |
1052 | ||
1053 | /* SETTER must be an INSN of some kind that sets memory. Call | |
43c8a043 EB |
1054 | note_stores to examine each hunk of memory that is modified. */ |
1055 | mci.mem = x; | |
1056 | mci.conflict = false; | |
1057 | note_stores (PATTERN (setter), mems_conflict_for_gcse_p, &mci); | |
1058 | if (mci.conflict) | |
a13d4ebf | 1059 | return 1; |
a13d4ebf AM |
1060 | } |
1061 | return 0; | |
1062 | } | |
1063 | ||
cc2902df | 1064 | /* Return nonzero if the operands of expression X are unchanged from |
7506f491 DE |
1065 | the start of INSN's basic block up to but not including INSN. */ |
1066 | ||
1067 | static int | |
ed7a4b4b | 1068 | oprs_anticipatable_p (const_rtx x, const_rtx insn) |
7506f491 DE |
1069 | { |
1070 | return oprs_unchanged_p (x, insn, 0); | |
1071 | } | |
1072 | ||
cc2902df | 1073 | /* Return nonzero if the operands of expression X are unchanged from |
7506f491 DE |
1074 | INSN to the end of INSN's basic block. */ |
1075 | ||
1076 | static int | |
ed7a4b4b | 1077 | oprs_available_p (const_rtx x, const_rtx insn) |
7506f491 DE |
1078 | { |
1079 | return oprs_unchanged_p (x, insn, 1); | |
1080 | } | |
1081 | ||
1082 | /* Hash expression X. | |
c4c81601 RK |
1083 | |
1084 | MODE is only used if X is a CONST_INT. DO_NOT_RECORD_P is a boolean | |
1085 | indicating if a volatile operand is found or if the expression contains | |
b58b21d5 | 1086 | something we don't want to insert in the table. HASH_TABLE_SIZE is |
0516f6fe | 1087 | the current size of the hash table to be probed. */ |
7506f491 DE |
1088 | |
1089 | static unsigned int | |
ed7a4b4b | 1090 | hash_expr (const_rtx x, enum machine_mode mode, int *do_not_record_p, |
b58b21d5 | 1091 | int hash_table_size) |
7506f491 DE |
1092 | { |
1093 | unsigned int hash; | |
1094 | ||
1095 | *do_not_record_p = 0; | |
1096 | ||
43c8a043 | 1097 | hash = hash_rtx (x, mode, do_not_record_p, NULL, /*have_reg_qty=*/false); |
7506f491 DE |
1098 | return hash % hash_table_size; |
1099 | } | |
172890a2 | 1100 | |
0516f6fe | 1101 | /* Return nonzero if exp1 is equivalent to exp2. */ |
7506f491 DE |
1102 | |
1103 | static int | |
ed7a4b4b | 1104 | expr_equiv_p (const_rtx x, const_rtx y) |
7506f491 | 1105 | { |
0516f6fe | 1106 | return exp_equiv_p (x, y, 0, true); |
7506f491 DE |
1107 | } |
1108 | ||
02280659 | 1109 | /* Insert expression X in INSN in the hash TABLE. |
7506f491 DE |
1110 | If it is already present, record it as the last occurrence in INSN's |
1111 | basic block. | |
1112 | ||
1113 | MODE is the mode of the value X is being stored into. | |
1114 | It is only used if X is a CONST_INT. | |
1115 | ||
cc2902df | 1116 | ANTIC_P is nonzero if X is an anticipatable expression. |
20160347 MK |
1117 | AVAIL_P is nonzero if X is an available expression. |
1118 | ||
1119 | MAX_DISTANCE is the maximum distance in instructions this expression can | |
1120 | be moved. */ | |
7506f491 DE |
1121 | |
1122 | static void | |
1d088dee | 1123 | insert_expr_in_table (rtx x, enum machine_mode mode, rtx insn, int antic_p, |
20160347 | 1124 | int avail_p, int max_distance, struct hash_table_d *table) |
7506f491 DE |
1125 | { |
1126 | int found, do_not_record_p; | |
1127 | unsigned int hash; | |
1128 | struct expr *cur_expr, *last_expr = NULL; | |
1129 | struct occr *antic_occr, *avail_occr; | |
7506f491 | 1130 | |
02280659 | 1131 | hash = hash_expr (x, mode, &do_not_record_p, table->size); |
7506f491 DE |
1132 | |
1133 | /* Do not insert expression in table if it contains volatile operands, | |
1134 | or if hash_expr determines the expression is something we don't want | |
1135 | to or can't handle. */ | |
1136 | if (do_not_record_p) | |
1137 | return; | |
1138 | ||
02280659 | 1139 | cur_expr = table->table[hash]; |
7506f491 DE |
1140 | found = 0; |
1141 | ||
c4c81601 | 1142 | while (cur_expr && 0 == (found = expr_equiv_p (cur_expr->expr, x))) |
7506f491 DE |
1143 | { |
1144 | /* If the expression isn't found, save a pointer to the end of | |
1145 | the list. */ | |
1146 | last_expr = cur_expr; | |
1147 | cur_expr = cur_expr->next_same_hash; | |
1148 | } | |
1149 | ||
1150 | if (! found) | |
1151 | { | |
1b4572a8 | 1152 | cur_expr = GOBNEW (struct expr); |
7506f491 | 1153 | bytes_used += sizeof (struct expr); |
02280659 | 1154 | if (table->table[hash] == NULL) |
c4c81601 | 1155 | /* This is the first pattern that hashed to this index. */ |
02280659 | 1156 | table->table[hash] = cur_expr; |
7506f491 | 1157 | else |
c4c81601 RK |
1158 | /* Add EXPR to end of this hash chain. */ |
1159 | last_expr->next_same_hash = cur_expr; | |
1160 | ||
589005ff | 1161 | /* Set the fields of the expr element. */ |
7506f491 | 1162 | cur_expr->expr = x; |
02280659 | 1163 | cur_expr->bitmap_index = table->n_elems++; |
7506f491 DE |
1164 | cur_expr->next_same_hash = NULL; |
1165 | cur_expr->antic_occr = NULL; | |
1166 | cur_expr->avail_occr = NULL; | |
20160347 MK |
1167 | gcc_assert (max_distance >= 0); |
1168 | cur_expr->max_distance = max_distance; | |
7506f491 | 1169 | } |
20160347 MK |
1170 | else |
1171 | gcc_assert (cur_expr->max_distance == max_distance); | |
7506f491 DE |
1172 | |
1173 | /* Now record the occurrence(s). */ | |
7506f491 DE |
1174 | if (antic_p) |
1175 | { | |
1176 | antic_occr = cur_expr->antic_occr; | |
1177 | ||
b0de17ef SB |
1178 | if (antic_occr |
1179 | && BLOCK_FOR_INSN (antic_occr->insn) != BLOCK_FOR_INSN (insn)) | |
b6e47ceb | 1180 | antic_occr = NULL; |
7506f491 DE |
1181 | |
1182 | if (antic_occr) | |
c4c81601 RK |
1183 | /* Found another instance of the expression in the same basic block. |
1184 | Prefer the currently recorded one. We want the first one in the | |
1185 | block and the block is scanned from start to end. */ | |
1186 | ; /* nothing to do */ | |
7506f491 DE |
1187 | else |
1188 | { | |
1189 | /* First occurrence of this expression in this basic block. */ | |
1b4572a8 | 1190 | antic_occr = GOBNEW (struct occr); |
7506f491 | 1191 | bytes_used += sizeof (struct occr); |
7506f491 | 1192 | antic_occr->insn = insn; |
b6e47ceb | 1193 | antic_occr->next = cur_expr->antic_occr; |
f9957958 | 1194 | antic_occr->deleted_p = 0; |
b6e47ceb | 1195 | cur_expr->antic_occr = antic_occr; |
7506f491 DE |
1196 | } |
1197 | } | |
1198 | ||
1199 | if (avail_p) | |
1200 | { | |
1201 | avail_occr = cur_expr->avail_occr; | |
1202 | ||
b0de17ef SB |
1203 | if (avail_occr |
1204 | && BLOCK_FOR_INSN (avail_occr->insn) == BLOCK_FOR_INSN (insn)) | |
7506f491 | 1205 | { |
b6e47ceb JL |
1206 | /* Found another instance of the expression in the same basic block. |
1207 | Prefer this occurrence to the currently recorded one. We want | |
1208 | the last one in the block and the block is scanned from start | |
1209 | to end. */ | |
1210 | avail_occr->insn = insn; | |
7506f491 | 1211 | } |
7506f491 DE |
1212 | else |
1213 | { | |
1214 | /* First occurrence of this expression in this basic block. */ | |
1b4572a8 | 1215 | avail_occr = GOBNEW (struct occr); |
7506f491 | 1216 | bytes_used += sizeof (struct occr); |
7506f491 | 1217 | avail_occr->insn = insn; |
b6e47ceb | 1218 | avail_occr->next = cur_expr->avail_occr; |
f9957958 | 1219 | avail_occr->deleted_p = 0; |
b6e47ceb | 1220 | cur_expr->avail_occr = avail_occr; |
7506f491 DE |
1221 | } |
1222 | } | |
1223 | } | |
1224 | ||
43c8a043 | 1225 | /* Scan SET present in INSN and add an entry to the hash TABLE. */ |
7506f491 DE |
1226 | |
1227 | static void | |
43c8a043 | 1228 | hash_scan_set (rtx set, rtx insn, struct hash_table_d *table) |
7506f491 | 1229 | { |
43c8a043 EB |
1230 | rtx src = SET_SRC (set); |
1231 | rtx dest = SET_DEST (set); | |
172890a2 | 1232 | rtx note; |
7506f491 | 1233 | |
6e72d1e9 | 1234 | if (GET_CODE (src) == CALL) |
02280659 | 1235 | hash_scan_call (src, insn, table); |
7506f491 | 1236 | |
7b1b4aed | 1237 | else if (REG_P (dest)) |
7506f491 | 1238 | { |
172890a2 | 1239 | unsigned int regno = REGNO (dest); |
20160347 | 1240 | int max_distance = 0; |
7506f491 | 1241 | |
29470771 SB |
1242 | /* See if a REG_EQUAL note shows this equivalent to a simpler expression. |
1243 | ||
90631280 PB |
1244 | This allows us to do a single GCSE pass and still eliminate |
1245 | redundant constants, addresses or other expressions that are | |
29470771 SB |
1246 | constructed with multiple instructions. |
1247 | ||
e45425ec | 1248 | However, keep the original SRC if INSN is a simple reg-reg move. |
29470771 SB |
1249 | In this case, there will almost always be a REG_EQUAL note on the |
1250 | insn that sets SRC. By recording the REG_EQUAL value here as SRC | |
1251 | for INSN, we miss copy propagation opportunities and we perform the | |
1252 | same PRE GCSE operation repeatedly on the same REG_EQUAL value if we | |
1253 | do more than one PRE GCSE pass. | |
1254 | ||
fa10beec | 1255 | Note that this does not impede profitable constant propagations. We |
29470771 | 1256 | "look through" reg-reg sets in lookup_avail_set. */ |
90631280 PB |
1257 | note = find_reg_equal_equiv_note (insn); |
1258 | if (note != 0 | |
29470771 SB |
1259 | && REG_NOTE_KIND (note) == REG_EQUAL |
1260 | && !REG_P (src) | |
e45425ec | 1261 | && want_to_gcse_p (XEXP (note, 0), NULL)) |
43c8a043 | 1262 | src = XEXP (note, 0), set = gen_rtx_SET (VOIDmode, dest, src); |
172890a2 | 1263 | |
7506f491 | 1264 | /* Only record sets of pseudo-regs in the hash table. */ |
e45425ec | 1265 | if (regno >= FIRST_PSEUDO_REGISTER |
7506f491 | 1266 | /* Don't GCSE something if we can't do a reg/reg copy. */ |
773eae39 | 1267 | && can_copy_p (GET_MODE (dest)) |
068473ec | 1268 | /* GCSE commonly inserts instruction after the insn. We can't |
1d65f45c RH |
1269 | do that easily for EH edges so disable GCSE on these for now. */ |
1270 | /* ??? We can now easily create new EH landing pads at the | |
1271 | gimple level, for splitting edges; there's no reason we | |
1272 | can't do the same thing at the rtl level. */ | |
1273 | && !can_throw_internal (insn) | |
7506f491 | 1274 | /* Is SET_SRC something we want to gcse? */ |
20160347 | 1275 | && want_to_gcse_p (src, &max_distance) |
172890a2 | 1276 | /* Don't CSE a nop. */ |
43c8a043 | 1277 | && ! set_noop_p (set) |
43e72072 JJ |
1278 | /* Don't GCSE if it has attached REG_EQUIV note. |
1279 | At this point this only function parameters should have | |
1280 | REG_EQUIV notes and if the argument slot is used somewhere | |
a1f300c0 | 1281 | explicitly, it means address of parameter has been taken, |
43e72072 | 1282 | so we should not extend the lifetime of the pseudo. */ |
90631280 | 1283 | && (note == NULL_RTX || ! MEM_P (XEXP (note, 0)))) |
7506f491 DE |
1284 | { |
1285 | /* An expression is not anticipatable if its operands are | |
52d76e11 | 1286 | modified before this insn or if this is not the only SET in |
6fb5fa3c DB |
1287 | this insn. The latter condition does not have to mean that |
1288 | SRC itself is not anticipatable, but we just will not be | |
1289 | able to handle code motion of insns with multiple sets. */ | |
1290 | int antic_p = oprs_anticipatable_p (src, insn) | |
1291 | && !multiple_sets (insn); | |
7506f491 | 1292 | /* An expression is not available if its operands are |
eb296bd9 GK |
1293 | subsequently modified, including this insn. It's also not |
1294 | available if this is a branch, because we can't insert | |
1295 | a set after the branch. */ | |
1296 | int avail_p = (oprs_available_p (src, insn) | |
1297 | && ! JUMP_P (insn)); | |
c4c81601 | 1298 | |
20160347 MK |
1299 | insert_expr_in_table (src, GET_MODE (dest), insn, antic_p, avail_p, |
1300 | max_distance, table); | |
7506f491 | 1301 | } |
7506f491 | 1302 | } |
d91edf86 | 1303 | /* In case of store we want to consider the memory value as available in |
f5f2e3cd MH |
1304 | the REG stored in that memory. This makes it possible to remove |
1305 | redundant loads from due to stores to the same location. */ | |
7b1b4aed | 1306 | else if (flag_gcse_las && REG_P (src) && MEM_P (dest)) |
f5f2e3cd MH |
1307 | { |
1308 | unsigned int regno = REGNO (src); | |
fb039b24 | 1309 | int max_distance = 0; |
f5f2e3cd | 1310 | |
e45425ec SB |
1311 | /* Only record sets of pseudo-regs in the hash table. */ |
1312 | if (regno >= FIRST_PSEUDO_REGISTER | |
f5f2e3cd MH |
1313 | /* Don't GCSE something if we can't do a reg/reg copy. */ |
1314 | && can_copy_p (GET_MODE (src)) | |
1315 | /* GCSE commonly inserts instruction after the insn. We can't | |
1d65f45c RH |
1316 | do that easily for EH edges so disable GCSE on these for now. */ |
1317 | && !can_throw_internal (insn) | |
f5f2e3cd | 1318 | /* Is SET_DEST something we want to gcse? */ |
fb039b24 | 1319 | && want_to_gcse_p (dest, &max_distance) |
f5f2e3cd | 1320 | /* Don't CSE a nop. */ |
43c8a043 | 1321 | && ! set_noop_p (set) |
f5f2e3cd MH |
1322 | /* Don't GCSE if it has attached REG_EQUIV note. |
1323 | At this point this only function parameters should have | |
1324 | REG_EQUIV notes and if the argument slot is used somewhere | |
1325 | explicitly, it means address of parameter has been taken, | |
1326 | so we should not extend the lifetime of the pseudo. */ | |
1327 | && ((note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) == 0 | |
7b1b4aed | 1328 | || ! MEM_P (XEXP (note, 0)))) |
f5f2e3cd MH |
1329 | { |
1330 | /* Stores are never anticipatable. */ | |
1331 | int antic_p = 0; | |
1332 | /* An expression is not available if its operands are | |
1333 | subsequently modified, including this insn. It's also not | |
1334 | available if this is a branch, because we can't insert | |
1335 | a set after the branch. */ | |
1336 | int avail_p = oprs_available_p (dest, insn) | |
1337 | && ! JUMP_P (insn); | |
1338 | ||
1339 | /* Record the memory expression (DEST) in the hash table. */ | |
4bcaf354 | 1340 | insert_expr_in_table (dest, GET_MODE (dest), insn, |
fb039b24 | 1341 | antic_p, avail_p, max_distance, table); |
f5f2e3cd MH |
1342 | } |
1343 | } | |
7506f491 DE |
1344 | } |
1345 | ||
1346 | static void | |
1d088dee | 1347 | hash_scan_clobber (rtx x ATTRIBUTE_UNUSED, rtx insn ATTRIBUTE_UNUSED, |
7e5487a2 | 1348 | struct hash_table_d *table ATTRIBUTE_UNUSED) |
7506f491 DE |
1349 | { |
1350 | /* Currently nothing to do. */ | |
1351 | } | |
1352 | ||
1353 | static void | |
1d088dee | 1354 | hash_scan_call (rtx x ATTRIBUTE_UNUSED, rtx insn ATTRIBUTE_UNUSED, |
7e5487a2 | 1355 | struct hash_table_d *table ATTRIBUTE_UNUSED) |
7506f491 DE |
1356 | { |
1357 | /* Currently nothing to do. */ | |
1358 | } | |
1359 | ||
43c8a043 | 1360 | /* Process INSN and add hash table entries as appropriate. */ |
7506f491 DE |
1361 | |
1362 | static void | |
7e5487a2 | 1363 | hash_scan_insn (rtx insn, struct hash_table_d *table) |
7506f491 DE |
1364 | { |
1365 | rtx pat = PATTERN (insn); | |
c4c81601 | 1366 | int i; |
7506f491 DE |
1367 | |
1368 | /* Pick out the sets of INSN and for other forms of instructions record | |
1369 | what's been modified. */ | |
1370 | ||
172890a2 | 1371 | if (GET_CODE (pat) == SET) |
02280659 | 1372 | hash_scan_set (pat, insn, table); |
43c8a043 EB |
1373 | |
1374 | else if (GET_CODE (pat) == CLOBBER) | |
1375 | hash_scan_clobber (pat, insn, table); | |
1376 | ||
1377 | else if (GET_CODE (pat) == CALL) | |
1378 | hash_scan_call (pat, insn, table); | |
1379 | ||
7506f491 | 1380 | else if (GET_CODE (pat) == PARALLEL) |
c4c81601 RK |
1381 | for (i = 0; i < XVECLEN (pat, 0); i++) |
1382 | { | |
1383 | rtx x = XVECEXP (pat, 0, i); | |
7506f491 | 1384 | |
c4c81601 | 1385 | if (GET_CODE (x) == SET) |
02280659 | 1386 | hash_scan_set (x, insn, table); |
c4c81601 | 1387 | else if (GET_CODE (x) == CLOBBER) |
02280659 | 1388 | hash_scan_clobber (x, insn, table); |
6e72d1e9 | 1389 | else if (GET_CODE (x) == CALL) |
02280659 | 1390 | hash_scan_call (x, insn, table); |
c4c81601 | 1391 | } |
7506f491 DE |
1392 | } |
1393 | ||
43c8a043 EB |
1394 | /* Dump the hash table TABLE to file FILE under the name NAME. */ |
1395 | ||
7506f491 | 1396 | static void |
7e5487a2 | 1397 | dump_hash_table (FILE *file, const char *name, struct hash_table_d *table) |
7506f491 DE |
1398 | { |
1399 | int i; | |
1400 | /* Flattened out table, so it's printed in proper order. */ | |
4da896b2 MM |
1401 | struct expr **flat_table; |
1402 | unsigned int *hash_val; | |
c4c81601 | 1403 | struct expr *expr; |
4da896b2 | 1404 | |
1b4572a8 KG |
1405 | flat_table = XCNEWVEC (struct expr *, table->n_elems); |
1406 | hash_val = XNEWVEC (unsigned int, table->n_elems); | |
7506f491 | 1407 | |
02280659 ZD |
1408 | for (i = 0; i < (int) table->size; i++) |
1409 | for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash) | |
c4c81601 RK |
1410 | { |
1411 | flat_table[expr->bitmap_index] = expr; | |
1412 | hash_val[expr->bitmap_index] = i; | |
1413 | } | |
7506f491 DE |
1414 | |
1415 | fprintf (file, "%s hash table (%d buckets, %d entries)\n", | |
02280659 | 1416 | name, table->size, table->n_elems); |
7506f491 | 1417 | |
02280659 | 1418 | for (i = 0; i < (int) table->n_elems; i++) |
21318741 RK |
1419 | if (flat_table[i] != 0) |
1420 | { | |
a0ac9e5a | 1421 | expr = flat_table[i]; |
20160347 MK |
1422 | fprintf (file, "Index %d (hash value %d; max distance %d)\n ", |
1423 | expr->bitmap_index, hash_val[i], expr->max_distance); | |
a0ac9e5a | 1424 | print_rtl (file, expr->expr); |
21318741 RK |
1425 | fprintf (file, "\n"); |
1426 | } | |
7506f491 DE |
1427 | |
1428 | fprintf (file, "\n"); | |
4da896b2 | 1429 | |
4da896b2 MM |
1430 | free (flat_table); |
1431 | free (hash_val); | |
7506f491 DE |
1432 | } |
1433 | ||
1434 | /* Record register first/last/block set information for REGNO in INSN. | |
c4c81601 | 1435 | |
80c29cc4 | 1436 | first_set records the first place in the block where the register |
7506f491 | 1437 | is set and is used to compute "anticipatability". |
c4c81601 | 1438 | |
80c29cc4 | 1439 | last_set records the last place in the block where the register |
7506f491 | 1440 | is set and is used to compute "availability". |
c4c81601 | 1441 | |
80c29cc4 | 1442 | last_bb records the block for which first_set and last_set are |
4a81774c | 1443 | valid, as a quick test to invalidate them. */ |
7506f491 DE |
1444 | |
1445 | static void | |
1d088dee | 1446 | record_last_reg_set_info (rtx insn, int regno) |
7506f491 | 1447 | { |
80c29cc4 | 1448 | struct reg_avail_info *info = ®_avail_info[regno]; |
4a81774c | 1449 | int luid = DF_INSN_LUID (insn); |
c4c81601 | 1450 | |
4a81774c | 1451 | info->last_set = luid; |
80c29cc4 RZ |
1452 | if (info->last_bb != current_bb) |
1453 | { | |
1454 | info->last_bb = current_bb; | |
4a81774c | 1455 | info->first_set = luid; |
80c29cc4 | 1456 | } |
7506f491 DE |
1457 | } |
1458 | ||
a13d4ebf AM |
1459 | /* Record all of the canonicalized MEMs of record_last_mem_set_info's insn. |
1460 | Note we store a pair of elements in the list, so they have to be | |
1461 | taken off pairwise. */ | |
1462 | ||
589005ff | 1463 | static void |
43c8a043 | 1464 | canon_list_insert (rtx dest ATTRIBUTE_UNUSED, const_rtx x ATTRIBUTE_UNUSED, |
1d088dee | 1465 | void * v_insn) |
a13d4ebf AM |
1466 | { |
1467 | rtx dest_addr, insn; | |
0fe854a7 | 1468 | int bb; |
f32682ca | 1469 | modify_pair pair; |
a13d4ebf AM |
1470 | |
1471 | while (GET_CODE (dest) == SUBREG | |
1472 | || GET_CODE (dest) == ZERO_EXTRACT | |
a13d4ebf AM |
1473 | || GET_CODE (dest) == STRICT_LOW_PART) |
1474 | dest = XEXP (dest, 0); | |
1475 | ||
1476 | /* If DEST is not a MEM, then it will not conflict with a load. Note | |
1477 | that function calls are assumed to clobber memory, but are handled | |
1478 | elsewhere. */ | |
1479 | ||
7b1b4aed | 1480 | if (! MEM_P (dest)) |
a13d4ebf AM |
1481 | return; |
1482 | ||
1483 | dest_addr = get_addr (XEXP (dest, 0)); | |
1484 | dest_addr = canon_rtx (dest_addr); | |
589005ff | 1485 | insn = (rtx) v_insn; |
b0de17ef | 1486 | bb = BLOCK_FOR_INSN (insn)->index; |
a13d4ebf | 1487 | |
f32682ca DN |
1488 | pair.dest = dest; |
1489 | pair.dest_addr = dest_addr; | |
9771b263 | 1490 | canon_modify_mem_list[bb].safe_push (pair); |
a13d4ebf AM |
1491 | } |
1492 | ||
a13d4ebf AM |
1493 | /* Record memory modification information for INSN. We do not actually care |
1494 | about the memory location(s) that are set, or even how they are set (consider | |
1495 | a CALL_INSN). We merely need to record which insns modify memory. */ | |
7506f491 DE |
1496 | |
1497 | static void | |
1d088dee | 1498 | record_last_mem_set_info (rtx insn) |
7506f491 | 1499 | { |
85c0f02d SB |
1500 | int bb; |
1501 | ||
1502 | if (! flag_gcse_lm) | |
1503 | return; | |
0fe854a7 | 1504 | |
ccef9ef5 | 1505 | /* load_killed_in_block_p will handle the case of calls clobbering |
dc297297 | 1506 | everything. */ |
85c0f02d | 1507 | bb = BLOCK_FOR_INSN (insn)->index; |
9771b263 | 1508 | modify_mem_list[bb].safe_push (insn); |
0fe854a7 | 1509 | bitmap_set_bit (modify_mem_list_set, bb); |
a13d4ebf | 1510 | |
7b1b4aed | 1511 | if (CALL_P (insn)) |
6ce1edcf | 1512 | bitmap_set_bit (blocks_with_calls, bb); |
a13d4ebf | 1513 | else |
0fe854a7 | 1514 | note_stores (PATTERN (insn), canon_list_insert, (void*) insn); |
7506f491 DE |
1515 | } |
1516 | ||
7506f491 | 1517 | /* Called from compute_hash_table via note_stores to handle one |
84832317 MM |
1518 | SET or CLOBBER in an insn. DATA is really the instruction in which |
1519 | the SET is taking place. */ | |
7506f491 DE |
1520 | |
1521 | static void | |
7bc980e1 | 1522 | record_last_set_info (rtx dest, const_rtx setter ATTRIBUTE_UNUSED, void *data) |
7506f491 | 1523 | { |
84832317 MM |
1524 | rtx last_set_insn = (rtx) data; |
1525 | ||
7506f491 DE |
1526 | if (GET_CODE (dest) == SUBREG) |
1527 | dest = SUBREG_REG (dest); | |
1528 | ||
7b1b4aed | 1529 | if (REG_P (dest)) |
7506f491 | 1530 | record_last_reg_set_info (last_set_insn, REGNO (dest)); |
7b1b4aed | 1531 | else if (MEM_P (dest) |
7506f491 DE |
1532 | /* Ignore pushes, they clobber nothing. */ |
1533 | && ! push_operand (dest, GET_MODE (dest))) | |
1534 | record_last_mem_set_info (last_set_insn); | |
1535 | } | |
1536 | ||
e45425ec | 1537 | /* Top level function to create an expression hash table. |
7506f491 DE |
1538 | |
1539 | Expression entries are placed in the hash table if | |
1540 | - they are of the form (set (pseudo-reg) src), | |
1541 | - src is something we want to perform GCSE on, | |
1542 | - none of the operands are subsequently modified in the block | |
1543 | ||
7506f491 DE |
1544 | Currently src must be a pseudo-reg or a const_int. |
1545 | ||
02280659 | 1546 | TABLE is the table computed. */ |
7506f491 DE |
1547 | |
1548 | static void | |
7e5487a2 | 1549 | compute_hash_table_work (struct hash_table_d *table) |
7506f491 | 1550 | { |
5f39ad47 | 1551 | int i; |
7506f491 | 1552 | |
a13d4ebf | 1553 | /* re-Cache any INSN_LIST nodes we have allocated. */ |
73991d6a | 1554 | clear_modify_mem_tables (); |
7506f491 | 1555 | /* Some working arrays used to track first and last set in each block. */ |
5f39ad47 | 1556 | reg_avail_info = GNEWVEC (struct reg_avail_info, max_reg_num ()); |
80c29cc4 | 1557 | |
5f39ad47 | 1558 | for (i = 0; i < max_reg_num (); ++i) |
e0082a72 | 1559 | reg_avail_info[i].last_bb = NULL; |
7506f491 | 1560 | |
e0082a72 | 1561 | FOR_EACH_BB (current_bb) |
7506f491 DE |
1562 | { |
1563 | rtx insn; | |
770ae6cc | 1564 | unsigned int regno; |
7506f491 DE |
1565 | |
1566 | /* First pass over the instructions records information used to | |
4a81774c | 1567 | determine when registers and memory are first and last set. */ |
eb232f4e | 1568 | FOR_BB_INSNS (current_bb, insn) |
7506f491 | 1569 | { |
a344c9f1 | 1570 | if (!NONDEBUG_INSN_P (insn)) |
7506f491 DE |
1571 | continue; |
1572 | ||
7b1b4aed | 1573 | if (CALL_P (insn)) |
7506f491 | 1574 | { |
c7fb4c7a SB |
1575 | hard_reg_set_iterator hrsi; |
1576 | EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call, | |
1577 | 0, regno, hrsi) | |
1578 | record_last_reg_set_info (insn, regno); | |
c4c81601 | 1579 | |
e45425ec SB |
1580 | if (! RTL_CONST_OR_PURE_CALL_P (insn)) |
1581 | record_last_mem_set_info (insn); | |
7506f491 DE |
1582 | } |
1583 | ||
84832317 | 1584 | note_stores (PATTERN (insn), record_last_set_info, insn); |
7506f491 DE |
1585 | } |
1586 | ||
1587 | /* The next pass builds the hash table. */ | |
eb232f4e | 1588 | FOR_BB_INSNS (current_bb, insn) |
a344c9f1 | 1589 | if (NONDEBUG_INSN_P (insn)) |
4a8cae83 | 1590 | hash_scan_insn (insn, table); |
7506f491 DE |
1591 | } |
1592 | ||
80c29cc4 RZ |
1593 | free (reg_avail_info); |
1594 | reg_avail_info = NULL; | |
7506f491 DE |
1595 | } |
1596 | ||
02280659 | 1597 | /* Allocate space for the set/expr hash TABLE. |
e45425ec | 1598 | It is used to determine the number of buckets to use. */ |
7506f491 DE |
1599 | |
1600 | static void | |
e45425ec | 1601 | alloc_hash_table (struct hash_table_d *table) |
7506f491 DE |
1602 | { |
1603 | int n; | |
1604 | ||
b5b8b0ac AO |
1605 | n = get_max_insn_count (); |
1606 | ||
1607 | table->size = n / 4; | |
02280659 ZD |
1608 | if (table->size < 11) |
1609 | table->size = 11; | |
c4c81601 | 1610 | |
7506f491 DE |
1611 | /* Attempt to maintain efficient use of hash table. |
1612 | Making it an odd number is simplest for now. | |
1613 | ??? Later take some measurements. */ | |
02280659 ZD |
1614 | table->size |= 1; |
1615 | n = table->size * sizeof (struct expr *); | |
1b4572a8 | 1616 | table->table = GNEWVAR (struct expr *, n); |
7506f491 DE |
1617 | } |
1618 | ||
02280659 | 1619 | /* Free things allocated by alloc_hash_table. */ |
7506f491 DE |
1620 | |
1621 | static void | |
7e5487a2 | 1622 | free_hash_table (struct hash_table_d *table) |
7506f491 | 1623 | { |
02280659 | 1624 | free (table->table); |
7506f491 DE |
1625 | } |
1626 | ||
e45425ec | 1627 | /* Compute the expression hash table TABLE. */ |
7506f491 DE |
1628 | |
1629 | static void | |
7e5487a2 | 1630 | compute_hash_table (struct hash_table_d *table) |
7506f491 DE |
1631 | { |
1632 | /* Initialize count of number of entries in hash table. */ | |
02280659 | 1633 | table->n_elems = 0; |
703ad42b | 1634 | memset (table->table, 0, table->size * sizeof (struct expr *)); |
7506f491 | 1635 | |
02280659 | 1636 | compute_hash_table_work (table); |
7506f491 DE |
1637 | } |
1638 | \f | |
1639 | /* Expression tracking support. */ | |
1640 | ||
e45425ec SB |
1641 | /* Clear canon_modify_mem_list and modify_mem_list tables. */ |
1642 | static void | |
1643 | clear_modify_mem_tables (void) | |
0e3f0221 | 1644 | { |
e45425ec SB |
1645 | unsigned i; |
1646 | bitmap_iterator bi; | |
0e3f0221 | 1647 | |
e45425ec | 1648 | EXECUTE_IF_SET_IN_BITMAP (modify_mem_list_set, 0, i, bi) |
0e3f0221 | 1649 | { |
9771b263 DN |
1650 | modify_mem_list[i].release (); |
1651 | canon_modify_mem_list[i].release (); | |
0e3f0221 | 1652 | } |
e45425ec SB |
1653 | bitmap_clear (modify_mem_list_set); |
1654 | bitmap_clear (blocks_with_calls); | |
0e3f0221 RS |
1655 | } |
1656 | ||
e45425ec | 1657 | /* Release memory used by modify_mem_list_set. */ |
0e3f0221 | 1658 | |
e45425ec SB |
1659 | static void |
1660 | free_modify_mem_tables (void) | |
e129b3f9 | 1661 | { |
e45425ec SB |
1662 | clear_modify_mem_tables (); |
1663 | free (modify_mem_list); | |
1664 | free (canon_modify_mem_list); | |
1665 | modify_mem_list = 0; | |
1666 | canon_modify_mem_list = 0; | |
e129b3f9 | 1667 | } |
e45425ec SB |
1668 | \f |
1669 | /* For each block, compute whether X is transparent. X is either an | |
1670 | expression or an assignment [though we don't care which, for this context | |
1671 | an assignment is treated as an expression]. For each block where an | |
1672 | element of X is modified, reset the INDX bit in BMAP. */ | |
0e3f0221 | 1673 | |
e45425ec SB |
1674 | static void |
1675 | compute_transp (const_rtx x, int indx, sbitmap *bmap) | |
0e3f0221 | 1676 | { |
e45425ec SB |
1677 | int i, j; |
1678 | enum rtx_code code; | |
1679 | const char *fmt; | |
0e3f0221 | 1680 | |
e45425ec SB |
1681 | /* repeat is used to turn tail-recursion into iteration since GCC |
1682 | can't do it when there's no return value. */ | |
1683 | repeat: | |
0e3f0221 | 1684 | |
e45425ec SB |
1685 | if (x == 0) |
1686 | return; | |
72b8d451 | 1687 | |
e45425ec SB |
1688 | code = GET_CODE (x); |
1689 | switch (code) | |
0e3f0221 | 1690 | { |
e45425ec | 1691 | case REG: |
628f6a4e | 1692 | { |
e45425ec SB |
1693 | df_ref def; |
1694 | for (def = DF_REG_DEF_CHAIN (REGNO (x)); | |
1695 | def; | |
1696 | def = DF_REF_NEXT_REG (def)) | |
d7c028c0 | 1697 | bitmap_clear_bit (bmap[DF_REF_BB (def)->index], indx); |
628f6a4e | 1698 | } |
7821bfc7 | 1699 | |
e45425ec | 1700 | return; |
72b8d451 | 1701 | |
e45425ec SB |
1702 | case MEM: |
1703 | if (! MEM_READONLY_P (x)) | |
0e3f0221 | 1704 | { |
e45425ec SB |
1705 | bitmap_iterator bi; |
1706 | unsigned bb_index; | |
92390dd1 PB |
1707 | rtx x_addr; |
1708 | ||
1709 | x_addr = get_addr (XEXP (x, 0)); | |
1710 | x_addr = canon_rtx (x_addr); | |
e129b3f9 | 1711 | |
e45425ec SB |
1712 | /* First handle all the blocks with calls. We don't need to |
1713 | do any list walking for them. */ | |
1714 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_calls, 0, bb_index, bi) | |
1715 | { | |
d7c028c0 | 1716 | bitmap_clear_bit (bmap[bb_index], indx); |
e45425ec | 1717 | } |
0e3f0221 | 1718 | |
92390dd1 PB |
1719 | /* Now iterate over the blocks which have memory modifications |
1720 | but which do not have any calls. */ | |
1721 | EXECUTE_IF_AND_COMPL_IN_BITMAP (modify_mem_list_set, | |
1722 | blocks_with_calls, | |
1723 | 0, bb_index, bi) | |
1724 | { | |
1725 | vec<modify_pair> list | |
1726 | = canon_modify_mem_list[bb_index]; | |
1727 | modify_pair *pair; | |
1728 | unsigned ix; | |
1729 | ||
1730 | FOR_EACH_VEC_ELT_REVERSE (list, ix, pair) | |
1731 | { | |
1732 | rtx dest = pair->dest; | |
1733 | rtx dest_addr = pair->dest_addr; | |
1734 | ||
1735 | if (canon_true_dependence (dest, GET_MODE (dest), | |
1736 | dest_addr, x, x_addr)) | |
1737 | bitmap_clear_bit (bmap[bb_index], indx); | |
1738 | } | |
1739 | } | |
0e3f0221 | 1740 | } |
0e3f0221 | 1741 | |
e45425ec SB |
1742 | x = XEXP (x, 0); |
1743 | goto repeat; | |
0e3f0221 | 1744 | |
e45425ec SB |
1745 | case PC: |
1746 | case CC0: /*FIXME*/ | |
1747 | case CONST: | |
d8116890 | 1748 | CASE_CONST_ANY: |
e45425ec SB |
1749 | case SYMBOL_REF: |
1750 | case LABEL_REF: | |
1751 | case ADDR_VEC: | |
1752 | case ADDR_DIFF_VEC: | |
1753 | return; | |
0e3f0221 | 1754 | |
e45425ec SB |
1755 | default: |
1756 | break; | |
1757 | } | |
7821bfc7 | 1758 | |
e45425ec | 1759 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
0e3f0221 | 1760 | { |
e45425ec | 1761 | if (fmt[i] == 'e') |
0e3f0221 | 1762 | { |
e45425ec SB |
1763 | /* If we are about to do the last recursive call |
1764 | needed at this level, change it into iteration. | |
1765 | This function is called enough to be worth it. */ | |
1766 | if (i == 0) | |
1767 | { | |
1768 | x = XEXP (x, i); | |
1769 | goto repeat; | |
1770 | } | |
1771 | ||
1772 | compute_transp (XEXP (x, i), indx, bmap); | |
0e3f0221 | 1773 | } |
e45425ec SB |
1774 | else if (fmt[i] == 'E') |
1775 | for (j = 0; j < XVECLEN (x, i); j++) | |
1776 | compute_transp (XVECEXP (x, i, j), indx, bmap); | |
0e3f0221 | 1777 | } |
0e3f0221 RS |
1778 | } |
1779 | \f | |
a65f3558 | 1780 | /* Compute PRE+LCM working variables. */ |
7506f491 DE |
1781 | |
1782 | /* Local properties of expressions. */ | |
43c8a043 | 1783 | |
7506f491 | 1784 | /* Nonzero for expressions that are transparent in the block. */ |
a65f3558 | 1785 | static sbitmap *transp; |
7506f491 | 1786 | |
a65f3558 JL |
1787 | /* Nonzero for expressions that are computed (available) in the block. */ |
1788 | static sbitmap *comp; | |
7506f491 | 1789 | |
a65f3558 JL |
1790 | /* Nonzero for expressions that are locally anticipatable in the block. */ |
1791 | static sbitmap *antloc; | |
7506f491 | 1792 | |
a65f3558 JL |
1793 | /* Nonzero for expressions where this block is an optimal computation |
1794 | point. */ | |
1795 | static sbitmap *pre_optimal; | |
5c35539b | 1796 | |
a65f3558 JL |
1797 | /* Nonzero for expressions which are redundant in a particular block. */ |
1798 | static sbitmap *pre_redundant; | |
7506f491 | 1799 | |
a42cd965 AM |
1800 | /* Nonzero for expressions which should be inserted on a specific edge. */ |
1801 | static sbitmap *pre_insert_map; | |
1802 | ||
1803 | /* Nonzero for expressions which should be deleted in a specific block. */ | |
1804 | static sbitmap *pre_delete_map; | |
1805 | ||
a65f3558 | 1806 | /* Allocate vars used for PRE analysis. */ |
7506f491 DE |
1807 | |
1808 | static void | |
1d088dee | 1809 | alloc_pre_mem (int n_blocks, int n_exprs) |
7506f491 | 1810 | { |
a65f3558 JL |
1811 | transp = sbitmap_vector_alloc (n_blocks, n_exprs); |
1812 | comp = sbitmap_vector_alloc (n_blocks, n_exprs); | |
1813 | antloc = sbitmap_vector_alloc (n_blocks, n_exprs); | |
5faf03ae | 1814 | |
a42cd965 AM |
1815 | pre_optimal = NULL; |
1816 | pre_redundant = NULL; | |
1817 | pre_insert_map = NULL; | |
1818 | pre_delete_map = NULL; | |
a42cd965 | 1819 | ae_kill = sbitmap_vector_alloc (n_blocks, n_exprs); |
c4c81601 | 1820 | |
a42cd965 | 1821 | /* pre_insert and pre_delete are allocated later. */ |
7506f491 DE |
1822 | } |
1823 | ||
a65f3558 | 1824 | /* Free vars used for PRE analysis. */ |
7506f491 DE |
1825 | |
1826 | static void | |
1d088dee | 1827 | free_pre_mem (void) |
7506f491 | 1828 | { |
5a660bff DB |
1829 | sbitmap_vector_free (transp); |
1830 | sbitmap_vector_free (comp); | |
bd3675fc JL |
1831 | |
1832 | /* ANTLOC and AE_KILL are freed just after pre_lcm finishes. */ | |
7506f491 | 1833 | |
a42cd965 | 1834 | if (pre_optimal) |
5a660bff | 1835 | sbitmap_vector_free (pre_optimal); |
a42cd965 | 1836 | if (pre_redundant) |
5a660bff | 1837 | sbitmap_vector_free (pre_redundant); |
a42cd965 | 1838 | if (pre_insert_map) |
5a660bff | 1839 | sbitmap_vector_free (pre_insert_map); |
a42cd965 | 1840 | if (pre_delete_map) |
5a660bff | 1841 | sbitmap_vector_free (pre_delete_map); |
a42cd965 | 1842 | |
bd3675fc | 1843 | transp = comp = NULL; |
a42cd965 | 1844 | pre_optimal = pre_redundant = pre_insert_map = pre_delete_map = NULL; |
7506f491 DE |
1845 | } |
1846 | ||
9b774782 JL |
1847 | /* Remove certain expressions from anticipatable and transparent |
1848 | sets of basic blocks that have incoming abnormal edge. | |
1849 | For PRE remove potentially trapping expressions to avoid placing | |
1850 | them on abnormal edges. For hoisting remove memory references that | |
1851 | can be clobbered by calls. */ | |
7506f491 DE |
1852 | |
1853 | static void | |
9b774782 | 1854 | prune_expressions (bool pre_p) |
7506f491 | 1855 | { |
9b774782 | 1856 | sbitmap prune_exprs; |
43c8a043 | 1857 | struct expr *expr; |
b614171e | 1858 | unsigned int ui; |
9b774782 | 1859 | basic_block bb; |
c66e8ae9 | 1860 | |
9b774782 | 1861 | prune_exprs = sbitmap_alloc (expr_hash_table.n_elems); |
f61e445a | 1862 | bitmap_clear (prune_exprs); |
02280659 | 1863 | for (ui = 0; ui < expr_hash_table.size; ui++) |
b614171e | 1864 | { |
43c8a043 | 1865 | for (expr = expr_hash_table.table[ui]; expr; expr = expr->next_same_hash) |
9b774782 JL |
1866 | { |
1867 | /* Note potentially trapping expressions. */ | |
43c8a043 | 1868 | if (may_trap_p (expr->expr)) |
9b774782 | 1869 | { |
d7c028c0 | 1870 | bitmap_set_bit (prune_exprs, expr->bitmap_index); |
9b774782 JL |
1871 | continue; |
1872 | } | |
b614171e | 1873 | |
43c8a043 | 1874 | if (!pre_p && MEM_P (expr->expr)) |
9b774782 JL |
1875 | /* Note memory references that can be clobbered by a call. |
1876 | We do not split abnormal edges in hoisting, so would | |
1877 | a memory reference get hoisted along an abnormal edge, | |
1878 | it would be placed /before/ the call. Therefore, only | |
1879 | constant memory references can be hoisted along abnormal | |
1880 | edges. */ | |
1881 | { | |
43c8a043 EB |
1882 | if (GET_CODE (XEXP (expr->expr, 0)) == SYMBOL_REF |
1883 | && CONSTANT_POOL_ADDRESS_P (XEXP (expr->expr, 0))) | |
9b774782 | 1884 | continue; |
c66e8ae9 | 1885 | |
43c8a043 EB |
1886 | if (MEM_READONLY_P (expr->expr) |
1887 | && !MEM_VOLATILE_P (expr->expr) | |
1888 | && MEM_NOTRAP_P (expr->expr)) | |
9b774782 JL |
1889 | /* Constant memory reference, e.g., a PIC address. */ |
1890 | continue; | |
1891 | ||
1892 | /* ??? Optimally, we would use interprocedural alias | |
1893 | analysis to determine if this mem is actually killed | |
1894 | by this call. */ | |
1895 | ||
d7c028c0 | 1896 | bitmap_set_bit (prune_exprs, expr->bitmap_index); |
9b774782 JL |
1897 | } |
1898 | } | |
1899 | } | |
c66e8ae9 | 1900 | |
e0082a72 | 1901 | FOR_EACH_BB (bb) |
c66e8ae9 | 1902 | { |
b614171e | 1903 | edge e; |
628f6a4e | 1904 | edge_iterator ei; |
b614171e MM |
1905 | |
1906 | /* If the current block is the destination of an abnormal edge, we | |
9b774782 JL |
1907 | kill all trapping (for PRE) and memory (for hoist) expressions |
1908 | because we won't be able to properly place the instruction on | |
1909 | the edge. So make them neither anticipatable nor transparent. | |
1910 | This is fairly conservative. | |
1911 | ||
1912 | ??? For hoisting it may be necessary to check for set-and-jump | |
1913 | instructions here, not just for abnormal edges. The general problem | |
1914 | is that when an expression cannot not be placed right at the end of | |
1915 | a basic block we should account for any side-effects of a subsequent | |
1916 | jump instructions that could clobber the expression. It would | |
1917 | be best to implement this check along the lines of | |
b11f0116 | 1918 | should_hoist_expr_to_dom where the target block is already known |
9b774782 JL |
1919 | and, hence, there's no need to conservatively prune expressions on |
1920 | "intermediate" set-and-jump instructions. */ | |
628f6a4e | 1921 | FOR_EACH_EDGE (e, ei, bb->preds) |
9b774782 JL |
1922 | if ((e->flags & EDGE_ABNORMAL) |
1923 | && (pre_p || CALL_P (BB_END (e->src)))) | |
b614171e | 1924 | { |
f61e445a | 1925 | bitmap_and_compl (antloc[bb->index], |
9b774782 | 1926 | antloc[bb->index], prune_exprs); |
f61e445a | 1927 | bitmap_and_compl (transp[bb->index], |
9b774782 | 1928 | transp[bb->index], prune_exprs); |
b614171e MM |
1929 | break; |
1930 | } | |
9b774782 JL |
1931 | } |
1932 | ||
1933 | sbitmap_free (prune_exprs); | |
1934 | } | |
1935 | ||
29fa95ed JL |
1936 | /* It may be necessary to insert a large number of insns on edges to |
1937 | make the existing occurrences of expressions fully redundant. This | |
1938 | routine examines the set of insertions and deletions and if the ratio | |
1939 | of insertions to deletions is too high for a particular expression, then | |
1940 | the expression is removed from the insertion/deletion sets. | |
1941 | ||
1942 | N_ELEMS is the number of elements in the hash table. */ | |
1943 | ||
1944 | static void | |
1945 | prune_insertions_deletions (int n_elems) | |
1946 | { | |
1947 | sbitmap_iterator sbi; | |
1948 | sbitmap prune_exprs; | |
1949 | ||
1950 | /* We always use I to iterate over blocks/edges and J to iterate over | |
1951 | expressions. */ | |
1952 | unsigned int i, j; | |
1953 | ||
1954 | /* Counts for the number of times an expression needs to be inserted and | |
1955 | number of times an expression can be removed as a result. */ | |
1956 | int *insertions = GCNEWVEC (int, n_elems); | |
1957 | int *deletions = GCNEWVEC (int, n_elems); | |
1958 | ||
1959 | /* Set of expressions which require too many insertions relative to | |
1960 | the number of deletions achieved. We will prune these out of the | |
1961 | insertion/deletion sets. */ | |
1962 | prune_exprs = sbitmap_alloc (n_elems); | |
f61e445a | 1963 | bitmap_clear (prune_exprs); |
29fa95ed JL |
1964 | |
1965 | /* Iterate over the edges counting the number of times each expression | |
1966 | needs to be inserted. */ | |
1967 | for (i = 0; i < (unsigned) n_edges; i++) | |
1968 | { | |
d4ac4ce2 | 1969 | EXECUTE_IF_SET_IN_BITMAP (pre_insert_map[i], 0, j, sbi) |
29fa95ed JL |
1970 | insertions[j]++; |
1971 | } | |
1972 | ||
1973 | /* Similarly for deletions, but those occur in blocks rather than on | |
1974 | edges. */ | |
1975 | for (i = 0; i < (unsigned) last_basic_block; i++) | |
1976 | { | |
d4ac4ce2 | 1977 | EXECUTE_IF_SET_IN_BITMAP (pre_delete_map[i], 0, j, sbi) |
29fa95ed JL |
1978 | deletions[j]++; |
1979 | } | |
1980 | ||
1981 | /* Now that we have accurate counts, iterate over the elements in the | |
1982 | hash table and see if any need too many insertions relative to the | |
1983 | number of evaluations that can be removed. If so, mark them in | |
1984 | PRUNE_EXPRS. */ | |
1985 | for (j = 0; j < (unsigned) n_elems; j++) | |
1986 | if (deletions[j] | |
1987 | && ((unsigned) insertions[j] / deletions[j]) > MAX_GCSE_INSERTION_RATIO) | |
d7c028c0 | 1988 | bitmap_set_bit (prune_exprs, j); |
29fa95ed JL |
1989 | |
1990 | /* Now prune PRE_INSERT_MAP and PRE_DELETE_MAP based on PRUNE_EXPRS. */ | |
d4ac4ce2 | 1991 | EXECUTE_IF_SET_IN_BITMAP (prune_exprs, 0, j, sbi) |
29fa95ed JL |
1992 | { |
1993 | for (i = 0; i < (unsigned) n_edges; i++) | |
d7c028c0 | 1994 | bitmap_clear_bit (pre_insert_map[i], j); |
29fa95ed JL |
1995 | |
1996 | for (i = 0; i < (unsigned) last_basic_block; i++) | |
d7c028c0 | 1997 | bitmap_clear_bit (pre_delete_map[i], j); |
29fa95ed JL |
1998 | } |
1999 | ||
2000 | sbitmap_free (prune_exprs); | |
2001 | free (insertions); | |
2002 | free (deletions); | |
2003 | } | |
2004 | ||
9b774782 | 2005 | /* Top level routine to do the dataflow analysis needed by PRE. */ |
b614171e | 2006 | |
43c8a043 | 2007 | static struct edge_list * |
9b774782 JL |
2008 | compute_pre_data (void) |
2009 | { | |
43c8a043 | 2010 | struct edge_list *edge_list; |
9b774782 JL |
2011 | basic_block bb; |
2012 | ||
2013 | compute_local_properties (transp, comp, antloc, &expr_hash_table); | |
2014 | prune_expressions (true); | |
f61e445a | 2015 | bitmap_vector_clear (ae_kill, last_basic_block); |
9b774782 JL |
2016 | |
2017 | /* Compute ae_kill for each basic block using: | |
2018 | ||
2019 | ~(TRANSP | COMP) | |
2020 | */ | |
2021 | ||
2022 | FOR_EACH_BB (bb) | |
2023 | { | |
f61e445a LC |
2024 | bitmap_ior (ae_kill[bb->index], transp[bb->index], comp[bb->index]); |
2025 | bitmap_not (ae_kill[bb->index], ae_kill[bb->index]); | |
c66e8ae9 JL |
2026 | } |
2027 | ||
10d22567 | 2028 | edge_list = pre_edge_lcm (expr_hash_table.n_elems, transp, comp, antloc, |
a42cd965 | 2029 | ae_kill, &pre_insert_map, &pre_delete_map); |
5a660bff | 2030 | sbitmap_vector_free (antloc); |
bd3675fc | 2031 | antloc = NULL; |
5a660bff | 2032 | sbitmap_vector_free (ae_kill); |
589005ff | 2033 | ae_kill = NULL; |
29fa95ed JL |
2034 | |
2035 | prune_insertions_deletions (expr_hash_table.n_elems); | |
43c8a043 EB |
2036 | |
2037 | return edge_list; | |
7506f491 DE |
2038 | } |
2039 | \f | |
2040 | /* PRE utilities */ | |
2041 | ||
cc2902df | 2042 | /* Return nonzero if an occurrence of expression EXPR in OCCR_BB would reach |
a65f3558 | 2043 | block BB. |
7506f491 DE |
2044 | |
2045 | VISITED is a pointer to a working buffer for tracking which BB's have | |
2046 | been visited. It is NULL for the top-level call. | |
2047 | ||
2048 | We treat reaching expressions that go through blocks containing the same | |
2049 | reaching expression as "not reaching". E.g. if EXPR is generated in blocks | |
2050 | 2 and 3, INSN is in block 4, and 2->3->4, we treat the expression in block | |
2051 | 2 as not reaching. The intent is to improve the probability of finding | |
2052 | only one reaching expression and to reduce register lifetimes by picking | |
2053 | the closest such expression. */ | |
2054 | ||
2055 | static int | |
43c8a043 EB |
2056 | pre_expr_reaches_here_p_work (basic_block occr_bb, struct expr *expr, |
2057 | basic_block bb, char *visited) | |
7506f491 | 2058 | { |
36349f8b | 2059 | edge pred; |
628f6a4e | 2060 | edge_iterator ei; |
b8698a0f | 2061 | |
628f6a4e | 2062 | FOR_EACH_EDGE (pred, ei, bb->preds) |
7506f491 | 2063 | { |
e2d2ed72 | 2064 | basic_block pred_bb = pred->src; |
7506f491 | 2065 | |
36349f8b | 2066 | if (pred->src == ENTRY_BLOCK_PTR |
7506f491 | 2067 | /* Has predecessor has already been visited? */ |
0b17ab2f | 2068 | || visited[pred_bb->index]) |
c4c81601 RK |
2069 | ;/* Nothing to do. */ |
2070 | ||
7506f491 | 2071 | /* Does this predecessor generate this expression? */ |
d7c028c0 | 2072 | else if (bitmap_bit_p (comp[pred_bb->index], expr->bitmap_index)) |
7506f491 DE |
2073 | { |
2074 | /* Is this the occurrence we're looking for? | |
2075 | Note that there's only one generating occurrence per block | |
2076 | so we just need to check the block number. */ | |
a65f3558 | 2077 | if (occr_bb == pred_bb) |
7506f491 | 2078 | return 1; |
c4c81601 | 2079 | |
0b17ab2f | 2080 | visited[pred_bb->index] = 1; |
7506f491 DE |
2081 | } |
2082 | /* Ignore this predecessor if it kills the expression. */ | |
d7c028c0 | 2083 | else if (! bitmap_bit_p (transp[pred_bb->index], expr->bitmap_index)) |
0b17ab2f | 2084 | visited[pred_bb->index] = 1; |
c4c81601 | 2085 | |
7506f491 DE |
2086 | /* Neither gen nor kill. */ |
2087 | else | |
ac7c5af5 | 2088 | { |
0b17ab2f | 2089 | visited[pred_bb->index] = 1; |
89e606c9 | 2090 | if (pre_expr_reaches_here_p_work (occr_bb, expr, pred_bb, visited)) |
7506f491 | 2091 | return 1; |
ac7c5af5 | 2092 | } |
7506f491 DE |
2093 | } |
2094 | ||
2095 | /* All paths have been checked. */ | |
2096 | return 0; | |
2097 | } | |
283a2545 RL |
2098 | |
2099 | /* The wrapper for pre_expr_reaches_here_work that ensures that any | |
dc297297 | 2100 | memory allocated for that function is returned. */ |
283a2545 RL |
2101 | |
2102 | static int | |
1d088dee | 2103 | pre_expr_reaches_here_p (basic_block occr_bb, struct expr *expr, basic_block bb) |
283a2545 RL |
2104 | { |
2105 | int rval; | |
5ed6ace5 | 2106 | char *visited = XCNEWVEC (char, last_basic_block); |
283a2545 | 2107 | |
8e42ace1 | 2108 | rval = pre_expr_reaches_here_p_work (occr_bb, expr, bb, visited); |
283a2545 RL |
2109 | |
2110 | free (visited); | |
c4c81601 | 2111 | return rval; |
283a2545 | 2112 | } |
7506f491 | 2113 | \f |
43c8a043 | 2114 | /* Generate RTL to copy an EXPR to its `reaching_reg' and return it. */ |
a42cd965 AM |
2115 | |
2116 | static rtx | |
1d088dee | 2117 | process_insert_insn (struct expr *expr) |
a42cd965 AM |
2118 | { |
2119 | rtx reg = expr->reaching_reg; | |
43c8a043 | 2120 | /* Copy the expression to make sure we don't have any sharing issues. */ |
fb0c0a12 RK |
2121 | rtx exp = copy_rtx (expr->expr); |
2122 | rtx pat; | |
a42cd965 AM |
2123 | |
2124 | start_sequence (); | |
fb0c0a12 RK |
2125 | |
2126 | /* If the expression is something that's an operand, like a constant, | |
2127 | just copy it to a register. */ | |
2128 | if (general_operand (exp, GET_MODE (reg))) | |
2129 | emit_move_insn (reg, exp); | |
2130 | ||
2131 | /* Otherwise, make a new insn to compute this expression and make sure the | |
43c8a043 | 2132 | insn will be recognized (this also adds any needed CLOBBERs). */ |
282899df NS |
2133 | else |
2134 | { | |
2135 | rtx insn = emit_insn (gen_rtx_SET (VOIDmode, reg, exp)); | |
2136 | ||
57ac4c34 | 2137 | if (insn_invalid_p (insn, false)) |
2f021b67 | 2138 | gcc_unreachable (); |
282899df | 2139 | } |
b8698a0f | 2140 | |
2f937369 | 2141 | pat = get_insns (); |
a42cd965 AM |
2142 | end_sequence (); |
2143 | ||
2144 | return pat; | |
2145 | } | |
589005ff | 2146 | |
a65f3558 JL |
2147 | /* Add EXPR to the end of basic block BB. |
2148 | ||
eae7938e | 2149 | This is used by both the PRE and code hoisting. */ |
7506f491 DE |
2150 | |
2151 | static void | |
eae7938e | 2152 | insert_insn_end_basic_block (struct expr *expr, basic_block bb) |
7506f491 | 2153 | { |
a813c111 | 2154 | rtx insn = BB_END (bb); |
7506f491 DE |
2155 | rtx new_insn; |
2156 | rtx reg = expr->reaching_reg; | |
2157 | int regno = REGNO (reg); | |
2f937369 | 2158 | rtx pat, pat_end; |
7506f491 | 2159 | |
a42cd965 | 2160 | pat = process_insert_insn (expr); |
282899df | 2161 | gcc_assert (pat && INSN_P (pat)); |
2f937369 DM |
2162 | |
2163 | pat_end = pat; | |
2164 | while (NEXT_INSN (pat_end) != NULL_RTX) | |
2165 | pat_end = NEXT_INSN (pat_end); | |
7506f491 DE |
2166 | |
2167 | /* If the last insn is a jump, insert EXPR in front [taking care to | |
4d6922ee | 2168 | handle cc0, etc. properly]. Similarly we need to care trapping |
068473ec | 2169 | instructions in presence of non-call exceptions. */ |
7506f491 | 2170 | |
7b1b4aed | 2171 | if (JUMP_P (insn) |
4b4bf941 | 2172 | || (NONJUMP_INSN_P (insn) |
c5cbcccf ZD |
2173 | && (!single_succ_p (bb) |
2174 | || single_succ_edge (bb)->flags & EDGE_ABNORMAL))) | |
7506f491 | 2175 | { |
7506f491 DE |
2176 | #ifdef HAVE_cc0 |
2177 | /* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts | |
2178 | if cc0 isn't set. */ | |
39718607 | 2179 | rtx note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX); |
7506f491 DE |
2180 | if (note) |
2181 | insn = XEXP (note, 0); | |
2182 | else | |
2183 | { | |
2184 | rtx maybe_cc0_setter = prev_nonnote_insn (insn); | |
2185 | if (maybe_cc0_setter | |
2c3c49de | 2186 | && INSN_P (maybe_cc0_setter) |
7506f491 DE |
2187 | && sets_cc0_p (PATTERN (maybe_cc0_setter))) |
2188 | insn = maybe_cc0_setter; | |
2189 | } | |
2190 | #endif | |
2191 | /* FIXME: What if something in cc0/jump uses value set in new insn? */ | |
6fb5fa3c | 2192 | new_insn = emit_insn_before_noloc (pat, insn, bb); |
3947e2f9 | 2193 | } |
c4c81601 | 2194 | |
3947e2f9 RH |
2195 | /* Likewise if the last insn is a call, as will happen in the presence |
2196 | of exception handling. */ | |
7b1b4aed | 2197 | else if (CALL_P (insn) |
c5cbcccf ZD |
2198 | && (!single_succ_p (bb) |
2199 | || single_succ_edge (bb)->flags & EDGE_ABNORMAL)) | |
3947e2f9 | 2200 | { |
42db504c SB |
2201 | /* Keeping in mind targets with small register classes and parameters |
2202 | in registers, we search backward and place the instructions before | |
2203 | the first parameter is loaded. Do this for everyone for consistency | |
eae7938e | 2204 | and a presumption that we'll get better code elsewhere as well. */ |
3947e2f9 RH |
2205 | |
2206 | /* Since different machines initialize their parameter registers | |
2207 | in different orders, assume nothing. Collect the set of all | |
2208 | parameter registers. */ | |
a813c111 | 2209 | insn = find_first_parameter_load (insn, BB_HEAD (bb)); |
3947e2f9 | 2210 | |
b1d26727 JL |
2211 | /* If we found all the parameter loads, then we want to insert |
2212 | before the first parameter load. | |
2213 | ||
2214 | If we did not find all the parameter loads, then we might have | |
2215 | stopped on the head of the block, which could be a CODE_LABEL. | |
2216 | If we inserted before the CODE_LABEL, then we would be putting | |
2217 | the insn in the wrong basic block. In that case, put the insn | |
b5229628 | 2218 | after the CODE_LABEL. Also, respect NOTE_INSN_BASIC_BLOCK. */ |
7b1b4aed | 2219 | while (LABEL_P (insn) |
589ca5cb | 2220 | || NOTE_INSN_BASIC_BLOCK_P (insn)) |
b5229628 | 2221 | insn = NEXT_INSN (insn); |
c4c81601 | 2222 | |
6fb5fa3c | 2223 | new_insn = emit_insn_before_noloc (pat, insn, bb); |
7506f491 DE |
2224 | } |
2225 | else | |
6fb5fa3c | 2226 | new_insn = emit_insn_after_noloc (pat, insn, bb); |
7506f491 | 2227 | |
2f937369 | 2228 | while (1) |
a65f3558 | 2229 | { |
2f937369 | 2230 | if (INSN_P (pat)) |
4a81774c | 2231 | add_label_notes (PATTERN (pat), new_insn); |
2f937369 DM |
2232 | if (pat == pat_end) |
2233 | break; | |
2234 | pat = NEXT_INSN (pat); | |
a65f3558 | 2235 | } |
3947e2f9 | 2236 | |
7506f491 DE |
2237 | gcse_create_count++; |
2238 | ||
10d22567 | 2239 | if (dump_file) |
7506f491 | 2240 | { |
10d22567 | 2241 | fprintf (dump_file, "PRE/HOIST: end of bb %d, insn %d, ", |
0b17ab2f | 2242 | bb->index, INSN_UID (new_insn)); |
10d22567 | 2243 | fprintf (dump_file, "copying expression %d to reg %d\n", |
c4c81601 | 2244 | expr->bitmap_index, regno); |
7506f491 DE |
2245 | } |
2246 | } | |
2247 | ||
a42cd965 AM |
2248 | /* Insert partially redundant expressions on edges in the CFG to make |
2249 | the expressions fully redundant. */ | |
7506f491 | 2250 | |
a42cd965 | 2251 | static int |
1d088dee | 2252 | pre_edge_insert (struct edge_list *edge_list, struct expr **index_map) |
7506f491 | 2253 | { |
c4c81601 | 2254 | int e, i, j, num_edges, set_size, did_insert = 0; |
a65f3558 JL |
2255 | sbitmap *inserted; |
2256 | ||
a42cd965 AM |
2257 | /* Where PRE_INSERT_MAP is nonzero, we add the expression on that edge |
2258 | if it reaches any of the deleted expressions. */ | |
7506f491 | 2259 | |
a42cd965 AM |
2260 | set_size = pre_insert_map[0]->size; |
2261 | num_edges = NUM_EDGES (edge_list); | |
02280659 | 2262 | inserted = sbitmap_vector_alloc (num_edges, expr_hash_table.n_elems); |
f61e445a | 2263 | bitmap_vector_clear (inserted, num_edges); |
7506f491 | 2264 | |
a42cd965 | 2265 | for (e = 0; e < num_edges; e++) |
7506f491 DE |
2266 | { |
2267 | int indx; | |
e2d2ed72 | 2268 | basic_block bb = INDEX_EDGE_PRED_BB (edge_list, e); |
a65f3558 | 2269 | |
a65f3558 | 2270 | for (i = indx = 0; i < set_size; i++, indx += SBITMAP_ELT_BITS) |
7506f491 | 2271 | { |
a42cd965 | 2272 | SBITMAP_ELT_TYPE insert = pre_insert_map[e]->elms[i]; |
7506f491 | 2273 | |
43c8a043 EB |
2274 | for (j = indx; |
2275 | insert && j < (int) expr_hash_table.n_elems; | |
2276 | j++, insert >>= 1) | |
c4c81601 RK |
2277 | if ((insert & 1) != 0 && index_map[j]->reaching_reg != NULL_RTX) |
2278 | { | |
2279 | struct expr *expr = index_map[j]; | |
2280 | struct occr *occr; | |
a65f3558 | 2281 | |
ff7cc307 | 2282 | /* Now look at each deleted occurrence of this expression. */ |
c4c81601 RK |
2283 | for (occr = expr->antic_occr; occr != NULL; occr = occr->next) |
2284 | { | |
2285 | if (! occr->deleted_p) | |
2286 | continue; | |
2287 | ||
3f117656 | 2288 | /* Insert this expression on this edge if it would |
ff7cc307 | 2289 | reach the deleted occurrence in BB. */ |
d7c028c0 | 2290 | if (!bitmap_bit_p (inserted[e], j)) |
c4c81601 RK |
2291 | { |
2292 | rtx insn; | |
2293 | edge eg = INDEX_EDGE (edge_list, e); | |
2294 | ||
2295 | /* We can't insert anything on an abnormal and | |
2296 | critical edge, so we insert the insn at the end of | |
2297 | the previous block. There are several alternatives | |
2298 | detailed in Morgans book P277 (sec 10.5) for | |
2299 | handling this situation. This one is easiest for | |
2300 | now. */ | |
2301 | ||
b16aa8a5 | 2302 | if (eg->flags & EDGE_ABNORMAL) |
eae7938e | 2303 | insert_insn_end_basic_block (index_map[j], bb); |
c4c81601 RK |
2304 | else |
2305 | { | |
2306 | insn = process_insert_insn (index_map[j]); | |
2307 | insert_insn_on_edge (insn, eg); | |
2308 | } | |
2309 | ||
10d22567 | 2310 | if (dump_file) |
c4c81601 | 2311 | { |
5f39ad47 | 2312 | fprintf (dump_file, "PRE: edge (%d,%d), ", |
0b17ab2f RH |
2313 | bb->index, |
2314 | INDEX_EDGE_SUCC_BB (edge_list, e)->index); | |
10d22567 | 2315 | fprintf (dump_file, "copy expression %d\n", |
c4c81601 RK |
2316 | expr->bitmap_index); |
2317 | } | |
2318 | ||
a13d4ebf | 2319 | update_ld_motion_stores (expr); |
d7c028c0 | 2320 | bitmap_set_bit (inserted[e], j); |
c4c81601 RK |
2321 | did_insert = 1; |
2322 | gcse_create_count++; | |
2323 | } | |
2324 | } | |
2325 | } | |
7506f491 DE |
2326 | } |
2327 | } | |
5faf03ae | 2328 | |
5a660bff | 2329 | sbitmap_vector_free (inserted); |
a42cd965 | 2330 | return did_insert; |
7506f491 DE |
2331 | } |
2332 | ||
073089a7 | 2333 | /* Copy the result of EXPR->EXPR generated by INSN to EXPR->REACHING_REG. |
b885908b MH |
2334 | Given "old_reg <- expr" (INSN), instead of adding after it |
2335 | reaching_reg <- old_reg | |
2336 | it's better to do the following: | |
2337 | reaching_reg <- expr | |
2338 | old_reg <- reaching_reg | |
2339 | because this way copy propagation can discover additional PRE | |
f5f2e3cd MH |
2340 | opportunities. But if this fails, we try the old way. |
2341 | When "expr" is a store, i.e. | |
2342 | given "MEM <- old_reg", instead of adding after it | |
2343 | reaching_reg <- old_reg | |
2344 | it's better to add it before as follows: | |
2345 | reaching_reg <- old_reg | |
2346 | MEM <- reaching_reg. */ | |
7506f491 DE |
2347 | |
2348 | static void | |
1d088dee | 2349 | pre_insert_copy_insn (struct expr *expr, rtx insn) |
7506f491 DE |
2350 | { |
2351 | rtx reg = expr->reaching_reg; | |
2352 | int regno = REGNO (reg); | |
2353 | int indx = expr->bitmap_index; | |
073089a7 | 2354 | rtx pat = PATTERN (insn); |
64068ca2 | 2355 | rtx set, first_set, new_insn; |
b885908b | 2356 | rtx old_reg; |
073089a7 | 2357 | int i; |
7506f491 | 2358 | |
073089a7 | 2359 | /* This block matches the logic in hash_scan_insn. */ |
282899df | 2360 | switch (GET_CODE (pat)) |
073089a7 | 2361 | { |
282899df NS |
2362 | case SET: |
2363 | set = pat; | |
2364 | break; | |
2365 | ||
2366 | case PARALLEL: | |
073089a7 RS |
2367 | /* Search through the parallel looking for the set whose |
2368 | source was the expression that we're interested in. */ | |
64068ca2 | 2369 | first_set = NULL_RTX; |
073089a7 RS |
2370 | set = NULL_RTX; |
2371 | for (i = 0; i < XVECLEN (pat, 0); i++) | |
2372 | { | |
2373 | rtx x = XVECEXP (pat, 0, i); | |
64068ca2 | 2374 | if (GET_CODE (x) == SET) |
073089a7 | 2375 | { |
64068ca2 RS |
2376 | /* If the source was a REG_EQUAL or REG_EQUIV note, we |
2377 | may not find an equivalent expression, but in this | |
2378 | case the PARALLEL will have a single set. */ | |
2379 | if (first_set == NULL_RTX) | |
2380 | first_set = x; | |
2381 | if (expr_equiv_p (SET_SRC (x), expr->expr)) | |
2382 | { | |
2383 | set = x; | |
2384 | break; | |
2385 | } | |
073089a7 RS |
2386 | } |
2387 | } | |
64068ca2 RS |
2388 | |
2389 | gcc_assert (first_set); | |
2390 | if (set == NULL_RTX) | |
2391 | set = first_set; | |
282899df NS |
2392 | break; |
2393 | ||
2394 | default: | |
2395 | gcc_unreachable (); | |
073089a7 | 2396 | } |
c4c81601 | 2397 | |
7b1b4aed | 2398 | if (REG_P (SET_DEST (set))) |
073089a7 | 2399 | { |
f5f2e3cd MH |
2400 | old_reg = SET_DEST (set); |
2401 | /* Check if we can modify the set destination in the original insn. */ | |
2402 | if (validate_change (insn, &SET_DEST (set), reg, 0)) | |
2403 | { | |
2404 | new_insn = gen_move_insn (old_reg, reg); | |
2405 | new_insn = emit_insn_after (new_insn, insn); | |
f5f2e3cd MH |
2406 | } |
2407 | else | |
2408 | { | |
2409 | new_insn = gen_move_insn (reg, old_reg); | |
2410 | new_insn = emit_insn_after (new_insn, insn); | |
f5f2e3cd | 2411 | } |
073089a7 | 2412 | } |
f5f2e3cd | 2413 | else /* This is possible only in case of a store to memory. */ |
073089a7 | 2414 | { |
f5f2e3cd | 2415 | old_reg = SET_SRC (set); |
073089a7 | 2416 | new_insn = gen_move_insn (reg, old_reg); |
f5f2e3cd MH |
2417 | |
2418 | /* Check if we can modify the set source in the original insn. */ | |
2419 | if (validate_change (insn, &SET_SRC (set), reg, 0)) | |
2420 | new_insn = emit_insn_before (new_insn, insn); | |
2421 | else | |
2422 | new_insn = emit_insn_after (new_insn, insn); | |
073089a7 | 2423 | } |
7506f491 DE |
2424 | |
2425 | gcse_create_count++; | |
2426 | ||
10d22567 ZD |
2427 | if (dump_file) |
2428 | fprintf (dump_file, | |
a42cd965 | 2429 | "PRE: bb %d, insn %d, copy expression %d in insn %d to reg %d\n", |
b0de17ef | 2430 | BLOCK_FOR_INSN (insn)->index, INSN_UID (new_insn), indx, |
a42cd965 | 2431 | INSN_UID (insn), regno); |
7506f491 DE |
2432 | } |
2433 | ||
2434 | /* Copy available expressions that reach the redundant expression | |
2435 | to `reaching_reg'. */ | |
2436 | ||
2437 | static void | |
1d088dee | 2438 | pre_insert_copies (void) |
7506f491 | 2439 | { |
f5f2e3cd | 2440 | unsigned int i, added_copy; |
c4c81601 RK |
2441 | struct expr *expr; |
2442 | struct occr *occr; | |
2443 | struct occr *avail; | |
a65f3558 | 2444 | |
7506f491 DE |
2445 | /* For each available expression in the table, copy the result to |
2446 | `reaching_reg' if the expression reaches a deleted one. | |
2447 | ||
2448 | ??? The current algorithm is rather brute force. | |
2449 | Need to do some profiling. */ | |
2450 | ||
02280659 | 2451 | for (i = 0; i < expr_hash_table.size; i++) |
43c8a043 | 2452 | for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash) |
c4c81601 RK |
2453 | { |
2454 | /* If the basic block isn't reachable, PPOUT will be TRUE. However, | |
2455 | we don't want to insert a copy here because the expression may not | |
2456 | really be redundant. So only insert an insn if the expression was | |
2457 | deleted. This test also avoids further processing if the | |
2458 | expression wasn't deleted anywhere. */ | |
2459 | if (expr->reaching_reg == NULL) | |
2460 | continue; | |
7b1b4aed | 2461 | |
f5f2e3cd | 2462 | /* Set when we add a copy for that expression. */ |
7b1b4aed | 2463 | added_copy = 0; |
c4c81601 RK |
2464 | |
2465 | for (occr = expr->antic_occr; occr != NULL; occr = occr->next) | |
2466 | { | |
2467 | if (! occr->deleted_p) | |
2468 | continue; | |
7506f491 | 2469 | |
c4c81601 RK |
2470 | for (avail = expr->avail_occr; avail != NULL; avail = avail->next) |
2471 | { | |
2472 | rtx insn = avail->insn; | |
7506f491 | 2473 | |
c4c81601 RK |
2474 | /* No need to handle this one if handled already. */ |
2475 | if (avail->copied_p) | |
2476 | continue; | |
7506f491 | 2477 | |
c4c81601 | 2478 | /* Don't handle this one if it's a redundant one. */ |
4a81774c | 2479 | if (INSN_DELETED_P (insn)) |
c4c81601 | 2480 | continue; |
7506f491 | 2481 | |
c4c81601 | 2482 | /* Or if the expression doesn't reach the deleted one. */ |
589005ff | 2483 | if (! pre_expr_reaches_here_p (BLOCK_FOR_INSN (avail->insn), |
e2d2ed72 AM |
2484 | expr, |
2485 | BLOCK_FOR_INSN (occr->insn))) | |
c4c81601 | 2486 | continue; |
7506f491 | 2487 | |
f5f2e3cd MH |
2488 | added_copy = 1; |
2489 | ||
c4c81601 RK |
2490 | /* Copy the result of avail to reaching_reg. */ |
2491 | pre_insert_copy_insn (expr, insn); | |
2492 | avail->copied_p = 1; | |
2493 | } | |
2494 | } | |
f5f2e3cd | 2495 | |
7b1b4aed | 2496 | if (added_copy) |
f5f2e3cd | 2497 | update_ld_motion_stores (expr); |
c4c81601 | 2498 | } |
7506f491 DE |
2499 | } |
2500 | ||
10d1bb36 JH |
2501 | /* Emit move from SRC to DEST noting the equivalence with expression computed |
2502 | in INSN. */ | |
43c8a043 | 2503 | |
10d1bb36 | 2504 | static rtx |
43c8a043 | 2505 | gcse_emit_move_after (rtx dest, rtx src, rtx insn) |
10d1bb36 | 2506 | { |
60564289 | 2507 | rtx new_rtx; |
6bdb8dd6 | 2508 | rtx set = single_set (insn), set2; |
10d1bb36 | 2509 | rtx note; |
dca3da7a | 2510 | rtx eqv = NULL_RTX; |
10d1bb36 JH |
2511 | |
2512 | /* This should never fail since we're creating a reg->reg copy | |
2513 | we've verified to be valid. */ | |
2514 | ||
60564289 | 2515 | new_rtx = emit_insn_after (gen_move_insn (dest, src), insn); |
285464d0 | 2516 | |
dca3da7a SB |
2517 | /* Note the equivalence for local CSE pass. Take the note from the old |
2518 | set if there was one. Otherwise record the SET_SRC from the old set | |
2519 | unless DEST is also an operand of the SET_SRC. */ | |
60564289 | 2520 | set2 = single_set (new_rtx); |
6bdb8dd6 | 2521 | if (!set2 || !rtx_equal_p (SET_DEST (set2), dest)) |
60564289 | 2522 | return new_rtx; |
10d1bb36 JH |
2523 | if ((note = find_reg_equal_equiv_note (insn))) |
2524 | eqv = XEXP (note, 0); | |
dca3da7a SB |
2525 | else if (! REG_P (dest) |
2526 | || ! reg_mentioned_p (dest, SET_SRC (set))) | |
10d1bb36 JH |
2527 | eqv = SET_SRC (set); |
2528 | ||
dca3da7a SB |
2529 | if (eqv != NULL_RTX) |
2530 | set_unique_reg_note (new_rtx, REG_EQUAL, copy_insn_1 (eqv)); | |
10d1bb36 | 2531 | |
60564289 | 2532 | return new_rtx; |
10d1bb36 JH |
2533 | } |
2534 | ||
7506f491 | 2535 | /* Delete redundant computations. |
7506f491 DE |
2536 | Deletion is done by changing the insn to copy the `reaching_reg' of |
2537 | the expression into the result of the SET. It is left to later passes | |
2538 | (cprop, cse2, flow, combine, regmove) to propagate the copy or eliminate it. | |
2539 | ||
43c8a043 | 2540 | Return nonzero if a change is made. */ |
7506f491 DE |
2541 | |
2542 | static int | |
1d088dee | 2543 | pre_delete (void) |
7506f491 | 2544 | { |
2e653e39 | 2545 | unsigned int i; |
63bc1d05 | 2546 | int changed; |
c4c81601 RK |
2547 | struct expr *expr; |
2548 | struct occr *occr; | |
a65f3558 | 2549 | |
7506f491 | 2550 | changed = 0; |
02280659 | 2551 | for (i = 0; i < expr_hash_table.size; i++) |
43c8a043 | 2552 | for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash) |
c4c81601 RK |
2553 | { |
2554 | int indx = expr->bitmap_index; | |
7506f491 | 2555 | |
43c8a043 | 2556 | /* We only need to search antic_occr since we require ANTLOC != 0. */ |
c4c81601 RK |
2557 | for (occr = expr->antic_occr; occr != NULL; occr = occr->next) |
2558 | { | |
2559 | rtx insn = occr->insn; | |
2560 | rtx set; | |
e2d2ed72 | 2561 | basic_block bb = BLOCK_FOR_INSN (insn); |
7506f491 | 2562 | |
073089a7 | 2563 | /* We only delete insns that have a single_set. */ |
d7c028c0 | 2564 | if (bitmap_bit_p (pre_delete_map[bb->index], indx) |
6fb5fa3c DB |
2565 | && (set = single_set (insn)) != 0 |
2566 | && dbg_cnt (pre_insn)) | |
c4c81601 | 2567 | { |
c4c81601 RK |
2568 | /* Create a pseudo-reg to store the result of reaching |
2569 | expressions into. Get the mode for the new pseudo from | |
2570 | the mode of the original destination pseudo. */ | |
2571 | if (expr->reaching_reg == NULL) | |
46b71b03 | 2572 | expr->reaching_reg = gen_reg_rtx_and_attrs (SET_DEST (set)); |
c4c81601 | 2573 | |
43c8a043 | 2574 | gcse_emit_move_after (SET_DEST (set), expr->reaching_reg, insn); |
10d1bb36 JH |
2575 | delete_insn (insn); |
2576 | occr->deleted_p = 1; | |
10d1bb36 JH |
2577 | changed = 1; |
2578 | gcse_subst_count++; | |
7506f491 | 2579 | |
10d22567 | 2580 | if (dump_file) |
c4c81601 | 2581 | { |
10d22567 | 2582 | fprintf (dump_file, |
c4c81601 RK |
2583 | "PRE: redundant insn %d (expression %d) in ", |
2584 | INSN_UID (insn), indx); | |
10d22567 | 2585 | fprintf (dump_file, "bb %d, reaching reg is %d\n", |
0b17ab2f | 2586 | bb->index, REGNO (expr->reaching_reg)); |
c4c81601 RK |
2587 | } |
2588 | } | |
2589 | } | |
2590 | } | |
7506f491 DE |
2591 | |
2592 | return changed; | |
2593 | } | |
2594 | ||
2595 | /* Perform GCSE optimizations using PRE. | |
2596 | This is called by one_pre_gcse_pass after all the dataflow analysis | |
2597 | has been done. | |
2598 | ||
c4c81601 RK |
2599 | This is based on the original Morel-Renvoise paper Fred Chow's thesis, and |
2600 | lazy code motion from Knoop, Ruthing and Steffen as described in Advanced | |
2601 | Compiler Design and Implementation. | |
7506f491 | 2602 | |
c4c81601 RK |
2603 | ??? A new pseudo reg is created to hold the reaching expression. The nice |
2604 | thing about the classical approach is that it would try to use an existing | |
2605 | reg. If the register can't be adequately optimized [i.e. we introduce | |
2606 | reload problems], one could add a pass here to propagate the new register | |
2607 | through the block. | |
7506f491 | 2608 | |
c4c81601 RK |
2609 | ??? We don't handle single sets in PARALLELs because we're [currently] not |
2610 | able to copy the rest of the parallel when we insert copies to create full | |
2611 | redundancies from partial redundancies. However, there's no reason why we | |
2612 | can't handle PARALLELs in the cases where there are no partial | |
7506f491 DE |
2613 | redundancies. */ |
2614 | ||
2615 | static int | |
43c8a043 | 2616 | pre_gcse (struct edge_list *edge_list) |
7506f491 | 2617 | { |
2e653e39 RK |
2618 | unsigned int i; |
2619 | int did_insert, changed; | |
7506f491 | 2620 | struct expr **index_map; |
c4c81601 | 2621 | struct expr *expr; |
7506f491 DE |
2622 | |
2623 | /* Compute a mapping from expression number (`bitmap_index') to | |
2624 | hash table entry. */ | |
2625 | ||
5ed6ace5 | 2626 | index_map = XCNEWVEC (struct expr *, expr_hash_table.n_elems); |
02280659 | 2627 | for (i = 0; i < expr_hash_table.size; i++) |
43c8a043 | 2628 | for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash) |
c4c81601 | 2629 | index_map[expr->bitmap_index] = expr; |
7506f491 | 2630 | |
7506f491 DE |
2631 | /* Delete the redundant insns first so that |
2632 | - we know what register to use for the new insns and for the other | |
2633 | ones with reaching expressions | |
2634 | - we know which insns are redundant when we go to create copies */ | |
c4c81601 | 2635 | |
7506f491 | 2636 | changed = pre_delete (); |
a42cd965 | 2637 | did_insert = pre_edge_insert (edge_list, index_map); |
c4c81601 | 2638 | |
7506f491 | 2639 | /* In other places with reaching expressions, copy the expression to the |
a42cd965 | 2640 | specially allocated pseudo-reg that reaches the redundant expr. */ |
7506f491 | 2641 | pre_insert_copies (); |
a42cd965 AM |
2642 | if (did_insert) |
2643 | { | |
2644 | commit_edge_insertions (); | |
2645 | changed = 1; | |
2646 | } | |
7506f491 | 2647 | |
283a2545 | 2648 | free (index_map); |
7506f491 DE |
2649 | return changed; |
2650 | } | |
2651 | ||
2652 | /* Top level routine to perform one PRE GCSE pass. | |
2653 | ||
cc2902df | 2654 | Return nonzero if a change was made. */ |
7506f491 DE |
2655 | |
2656 | static int | |
5f39ad47 | 2657 | one_pre_gcse_pass (void) |
7506f491 DE |
2658 | { |
2659 | int changed = 0; | |
2660 | ||
2661 | gcse_subst_count = 0; | |
2662 | gcse_create_count = 0; | |
2663 | ||
5f39ad47 SB |
2664 | /* Return if there's nothing to do, or it is too expensive. */ |
2665 | if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1 | |
2666 | || is_too_expensive (_("PRE disabled"))) | |
2667 | return 0; | |
2668 | ||
2669 | /* We need alias. */ | |
2670 | init_alias_analysis (); | |
2671 | ||
2672 | bytes_used = 0; | |
2673 | gcc_obstack_init (&gcse_obstack); | |
2674 | alloc_gcse_mem (); | |
2675 | ||
e45425ec | 2676 | alloc_hash_table (&expr_hash_table); |
a42cd965 | 2677 | add_noreturn_fake_exit_edges (); |
a13d4ebf AM |
2678 | if (flag_gcse_lm) |
2679 | compute_ld_motion_mems (); | |
2680 | ||
02280659 | 2681 | compute_hash_table (&expr_hash_table); |
43c8a043 EB |
2682 | if (flag_gcse_lm) |
2683 | trim_ld_motion_mems (); | |
10d22567 ZD |
2684 | if (dump_file) |
2685 | dump_hash_table (dump_file, "Expression", &expr_hash_table); | |
c4c81601 | 2686 | |
02280659 | 2687 | if (expr_hash_table.n_elems > 0) |
7506f491 | 2688 | { |
43c8a043 | 2689 | struct edge_list *edge_list; |
02280659 | 2690 | alloc_pre_mem (last_basic_block, expr_hash_table.n_elems); |
43c8a043 EB |
2691 | edge_list = compute_pre_data (); |
2692 | changed |= pre_gcse (edge_list); | |
a42cd965 | 2693 | free_edge_list (edge_list); |
7506f491 DE |
2694 | free_pre_mem (); |
2695 | } | |
c4c81601 | 2696 | |
43c8a043 EB |
2697 | if (flag_gcse_lm) |
2698 | free_ld_motion_mems (); | |
6809cbf9 | 2699 | remove_fake_exit_edges (); |
02280659 | 2700 | free_hash_table (&expr_hash_table); |
7506f491 | 2701 | |
5f39ad47 SB |
2702 | free_gcse_mem (); |
2703 | obstack_free (&gcse_obstack, NULL); | |
2704 | ||
2705 | /* We are finished with alias. */ | |
2706 | end_alias_analysis (); | |
2707 | ||
10d22567 | 2708 | if (dump_file) |
7506f491 | 2709 | { |
5f39ad47 SB |
2710 | fprintf (dump_file, "PRE GCSE of %s, %d basic blocks, %d bytes needed, ", |
2711 | current_function_name (), n_basic_blocks, bytes_used); | |
10d22567 | 2712 | fprintf (dump_file, "%d substs, %d insns created\n", |
c4c81601 | 2713 | gcse_subst_count, gcse_create_count); |
7506f491 DE |
2714 | } |
2715 | ||
2716 | return changed; | |
2717 | } | |
aeb2f500 | 2718 | \f |
cf7c4aa6 HPN |
2719 | /* If X contains any LABEL_REF's, add REG_LABEL_OPERAND notes for them |
2720 | to INSN. If such notes are added to an insn which references a | |
2721 | CODE_LABEL, the LABEL_NUSES count is incremented. We have to add | |
2722 | that note, because the following loop optimization pass requires | |
2723 | them. */ | |
aeb2f500 | 2724 | |
aeb2f500 JW |
2725 | /* ??? If there was a jump optimization pass after gcse and before loop, |
2726 | then we would not need to do this here, because jump would add the | |
cf7c4aa6 | 2727 | necessary REG_LABEL_OPERAND and REG_LABEL_TARGET notes. */ |
aeb2f500 JW |
2728 | |
2729 | static void | |
1d088dee | 2730 | add_label_notes (rtx x, rtx insn) |
aeb2f500 JW |
2731 | { |
2732 | enum rtx_code code = GET_CODE (x); | |
2733 | int i, j; | |
6f7d635c | 2734 | const char *fmt; |
aeb2f500 JW |
2735 | |
2736 | if (code == LABEL_REF && !LABEL_REF_NONLOCAL_P (x)) | |
2737 | { | |
6b3603c2 | 2738 | /* This code used to ignore labels that referred to dispatch tables to |
e0bb17a8 | 2739 | avoid flow generating (slightly) worse code. |
6b3603c2 | 2740 | |
ac7c5af5 JL |
2741 | We no longer ignore such label references (see LABEL_REF handling in |
2742 | mark_jump_label for additional information). */ | |
c4c81601 | 2743 | |
cb2f563b HPN |
2744 | /* There's no reason for current users to emit jump-insns with |
2745 | such a LABEL_REF, so we don't have to handle REG_LABEL_TARGET | |
2746 | notes. */ | |
2747 | gcc_assert (!JUMP_P (insn)); | |
65c5f2a6 ILT |
2748 | add_reg_note (insn, REG_LABEL_OPERAND, XEXP (x, 0)); |
2749 | ||
cb2f563b HPN |
2750 | if (LABEL_P (XEXP (x, 0))) |
2751 | LABEL_NUSES (XEXP (x, 0))++; | |
2752 | ||
aeb2f500 JW |
2753 | return; |
2754 | } | |
2755 | ||
c4c81601 | 2756 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
aeb2f500 JW |
2757 | { |
2758 | if (fmt[i] == 'e') | |
2759 | add_label_notes (XEXP (x, i), insn); | |
2760 | else if (fmt[i] == 'E') | |
2761 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
2762 | add_label_notes (XVECEXP (x, i, j), insn); | |
2763 | } | |
2764 | } | |
a65f3558 | 2765 | |
bb457bd9 JL |
2766 | /* Code Hoisting variables and subroutines. */ |
2767 | ||
2768 | /* Very busy expressions. */ | |
2769 | static sbitmap *hoist_vbein; | |
2770 | static sbitmap *hoist_vbeout; | |
2771 | ||
bb457bd9 | 2772 | /* ??? We could compute post dominators and run this algorithm in |
68e82b83 | 2773 | reverse to perform tail merging, doing so would probably be |
bb457bd9 JL |
2774 | more effective than the tail merging code in jump.c. |
2775 | ||
2776 | It's unclear if tail merging could be run in parallel with | |
2777 | code hoisting. It would be nice. */ | |
2778 | ||
2779 | /* Allocate vars used for code hoisting analysis. */ | |
2780 | ||
2781 | static void | |
1d088dee | 2782 | alloc_code_hoist_mem (int n_blocks, int n_exprs) |
bb457bd9 JL |
2783 | { |
2784 | antloc = sbitmap_vector_alloc (n_blocks, n_exprs); | |
2785 | transp = sbitmap_vector_alloc (n_blocks, n_exprs); | |
2786 | comp = sbitmap_vector_alloc (n_blocks, n_exprs); | |
2787 | ||
2788 | hoist_vbein = sbitmap_vector_alloc (n_blocks, n_exprs); | |
2789 | hoist_vbeout = sbitmap_vector_alloc (n_blocks, n_exprs); | |
bb457bd9 JL |
2790 | } |
2791 | ||
2792 | /* Free vars used for code hoisting analysis. */ | |
2793 | ||
2794 | static void | |
1d088dee | 2795 | free_code_hoist_mem (void) |
bb457bd9 | 2796 | { |
5a660bff DB |
2797 | sbitmap_vector_free (antloc); |
2798 | sbitmap_vector_free (transp); | |
2799 | sbitmap_vector_free (comp); | |
bb457bd9 | 2800 | |
5a660bff DB |
2801 | sbitmap_vector_free (hoist_vbein); |
2802 | sbitmap_vector_free (hoist_vbeout); | |
bb457bd9 | 2803 | |
d47cc544 | 2804 | free_dominance_info (CDI_DOMINATORS); |
bb457bd9 JL |
2805 | } |
2806 | ||
2807 | /* Compute the very busy expressions at entry/exit from each block. | |
2808 | ||
2809 | An expression is very busy if all paths from a given point | |
2810 | compute the expression. */ | |
2811 | ||
2812 | static void | |
1d088dee | 2813 | compute_code_hoist_vbeinout (void) |
bb457bd9 | 2814 | { |
e0082a72 ZD |
2815 | int changed, passes; |
2816 | basic_block bb; | |
bb457bd9 | 2817 | |
f61e445a LC |
2818 | bitmap_vector_clear (hoist_vbeout, last_basic_block); |
2819 | bitmap_vector_clear (hoist_vbein, last_basic_block); | |
bb457bd9 JL |
2820 | |
2821 | passes = 0; | |
2822 | changed = 1; | |
c4c81601 | 2823 | |
bb457bd9 JL |
2824 | while (changed) |
2825 | { | |
2826 | changed = 0; | |
c4c81601 | 2827 | |
bb457bd9 JL |
2828 | /* We scan the blocks in the reverse order to speed up |
2829 | the convergence. */ | |
e0082a72 | 2830 | FOR_EACH_BB_REVERSE (bb) |
bb457bd9 | 2831 | { |
e0082a72 | 2832 | if (bb->next_bb != EXIT_BLOCK_PTR) |
ce4c0015 | 2833 | { |
d7c028c0 LC |
2834 | bitmap_intersection_of_succs (hoist_vbeout[bb->index], |
2835 | hoist_vbein, bb); | |
ce4c0015 MK |
2836 | |
2837 | /* Include expressions in VBEout that are calculated | |
2838 | in BB and available at its end. */ | |
f61e445a | 2839 | bitmap_ior (hoist_vbeout[bb->index], |
ce4c0015 MK |
2840 | hoist_vbeout[bb->index], comp[bb->index]); |
2841 | } | |
f8423fea | 2842 | |
f61e445a | 2843 | changed |= bitmap_or_and (hoist_vbein[bb->index], |
f8423fea SB |
2844 | antloc[bb->index], |
2845 | hoist_vbeout[bb->index], | |
2846 | transp[bb->index]); | |
bb457bd9 | 2847 | } |
c4c81601 | 2848 | |
bb457bd9 JL |
2849 | passes++; |
2850 | } | |
2851 | ||
10d22567 | 2852 | if (dump_file) |
cad9aa15 MK |
2853 | { |
2854 | fprintf (dump_file, "hoisting vbeinout computation: %d passes\n", passes); | |
2855 | ||
2856 | FOR_EACH_BB (bb) | |
2857 | { | |
2858 | fprintf (dump_file, "vbein (%d): ", bb->index); | |
f61e445a | 2859 | dump_bitmap_file (dump_file, hoist_vbein[bb->index]); |
cad9aa15 | 2860 | fprintf (dump_file, "vbeout(%d): ", bb->index); |
f61e445a | 2861 | dump_bitmap_file (dump_file, hoist_vbeout[bb->index]); |
cad9aa15 MK |
2862 | } |
2863 | } | |
bb457bd9 JL |
2864 | } |
2865 | ||
2866 | /* Top level routine to do the dataflow analysis needed by code hoisting. */ | |
2867 | ||
2868 | static void | |
1d088dee | 2869 | compute_code_hoist_data (void) |
bb457bd9 | 2870 | { |
02280659 | 2871 | compute_local_properties (transp, comp, antloc, &expr_hash_table); |
9b774782 | 2872 | prune_expressions (false); |
bb457bd9 | 2873 | compute_code_hoist_vbeinout (); |
d47cc544 | 2874 | calculate_dominance_info (CDI_DOMINATORS); |
10d22567 ZD |
2875 | if (dump_file) |
2876 | fprintf (dump_file, "\n"); | |
bb457bd9 JL |
2877 | } |
2878 | ||
4b8181c5 BC |
2879 | /* Update register pressure for BB when hoisting an expression from |
2880 | instruction FROM, if live ranges of inputs are shrunk. Also | |
2881 | maintain live_in information if live range of register referred | |
2882 | in FROM is shrunk. | |
2883 | ||
2884 | Return 0 if register pressure doesn't change, otherwise return | |
2885 | the number by which register pressure is decreased. | |
2886 | ||
2887 | NOTE: Register pressure won't be increased in this function. */ | |
2888 | ||
2889 | static int | |
2890 | update_bb_reg_pressure (basic_block bb, rtx from) | |
2891 | { | |
2892 | rtx dreg, insn; | |
2893 | basic_block succ_bb; | |
2894 | df_ref *op, op_ref; | |
2895 | edge succ; | |
2896 | edge_iterator ei; | |
2897 | int decreased_pressure = 0; | |
2898 | int nregs; | |
2899 | enum reg_class pressure_class; | |
2900 | ||
2901 | for (op = DF_INSN_USES (from); *op; op++) | |
2902 | { | |
2903 | dreg = DF_REF_REAL_REG (*op); | |
2904 | /* The live range of register is shrunk only if it isn't: | |
2905 | 1. referred on any path from the end of this block to EXIT, or | |
2906 | 2. referred by insns other than FROM in this block. */ | |
2907 | FOR_EACH_EDGE (succ, ei, bb->succs) | |
2908 | { | |
2909 | succ_bb = succ->dest; | |
2910 | if (succ_bb == EXIT_BLOCK_PTR) | |
2911 | continue; | |
2912 | ||
2913 | if (bitmap_bit_p (BB_DATA (succ_bb)->live_in, REGNO (dreg))) | |
2914 | break; | |
2915 | } | |
2916 | if (succ != NULL) | |
2917 | continue; | |
2918 | ||
2919 | op_ref = DF_REG_USE_CHAIN (REGNO (dreg)); | |
2920 | for (; op_ref; op_ref = DF_REF_NEXT_REG (op_ref)) | |
2921 | { | |
2922 | if (!DF_REF_INSN_INFO (op_ref)) | |
2923 | continue; | |
2924 | ||
2925 | insn = DF_REF_INSN (op_ref); | |
2926 | if (BLOCK_FOR_INSN (insn) == bb | |
2927 | && NONDEBUG_INSN_P (insn) && insn != from) | |
2928 | break; | |
2929 | } | |
2930 | ||
2931 | pressure_class = get_regno_pressure_class (REGNO (dreg), &nregs); | |
2932 | /* Decrease register pressure and update live_in information for | |
2933 | this block. */ | |
2934 | if (!op_ref && pressure_class != NO_REGS) | |
2935 | { | |
2936 | decreased_pressure += nregs; | |
2937 | BB_DATA (bb)->max_reg_pressure[pressure_class] -= nregs; | |
2938 | bitmap_clear_bit (BB_DATA (bb)->live_in, REGNO (dreg)); | |
2939 | } | |
2940 | } | |
2941 | return decreased_pressure; | |
2942 | } | |
2943 | ||
b11f0116 BC |
2944 | /* Determine if the expression EXPR should be hoisted to EXPR_BB up in |
2945 | flow graph, if it can reach BB unimpared. Stop the search if the | |
2946 | expression would need to be moved more than DISTANCE instructions. | |
2947 | ||
2948 | DISTANCE is the number of instructions through which EXPR can be | |
2949 | hoisted up in flow graph. | |
2950 | ||
2951 | BB_SIZE points to an array which contains the number of instructions | |
2952 | for each basic block. | |
2953 | ||
2954 | PRESSURE_CLASS and NREGS are register class and number of hard registers | |
2955 | for storing EXPR. | |
2956 | ||
2957 | HOISTED_BBS points to a bitmap indicating basic blocks through which | |
2958 | EXPR is hoisted. | |
bb457bd9 | 2959 | |
4b8181c5 BC |
2960 | FROM is the instruction from which EXPR is hoisted. |
2961 | ||
bb457bd9 JL |
2962 | It's unclear exactly what Muchnick meant by "unimpared". It seems |
2963 | to me that the expression must either be computed or transparent in | |
2964 | *every* block in the path(s) from EXPR_BB to BB. Any other definition | |
2965 | would allow the expression to be hoisted out of loops, even if | |
2966 | the expression wasn't a loop invariant. | |
2967 | ||
2968 | Contrast this to reachability for PRE where an expression is | |
2969 | considered reachable if *any* path reaches instead of *all* | |
2970 | paths. */ | |
2971 | ||
2972 | static int | |
b11f0116 BC |
2973 | should_hoist_expr_to_dom (basic_block expr_bb, struct expr *expr, |
2974 | basic_block bb, sbitmap visited, int distance, | |
2975 | int *bb_size, enum reg_class pressure_class, | |
4b8181c5 | 2976 | int *nregs, bitmap hoisted_bbs, rtx from) |
bb457bd9 | 2977 | { |
b11f0116 | 2978 | unsigned int i; |
bb457bd9 | 2979 | edge pred; |
628f6a4e | 2980 | edge_iterator ei; |
b11f0116 | 2981 | sbitmap_iterator sbi; |
283a2545 | 2982 | int visited_allocated_locally = 0; |
4b8181c5 | 2983 | int decreased_pressure = 0; |
589005ff | 2984 | |
4b8181c5 BC |
2985 | if (flag_ira_hoist_pressure) |
2986 | { | |
2987 | /* Record old information of basic block BB when it is visited | |
2988 | at the first time. */ | |
2989 | if (!bitmap_bit_p (hoisted_bbs, bb->index)) | |
2990 | { | |
2991 | struct bb_data *data = BB_DATA (bb); | |
2992 | bitmap_copy (data->backup, data->live_in); | |
2993 | data->old_pressure = data->max_reg_pressure[pressure_class]; | |
2994 | } | |
2995 | decreased_pressure = update_bb_reg_pressure (bb, from); | |
2996 | } | |
20160347 MK |
2997 | /* Terminate the search if distance, for which EXPR is allowed to move, |
2998 | is exhausted. */ | |
2999 | if (distance > 0) | |
3000 | { | |
4b8181c5 BC |
3001 | if (flag_ira_hoist_pressure) |
3002 | { | |
3003 | /* Prefer to hoist EXPR if register pressure is decreased. */ | |
3004 | if (decreased_pressure > *nregs) | |
3005 | distance += bb_size[bb->index]; | |
3006 | /* Let EXPR be hoisted through basic block at no cost if one | |
3007 | of following conditions is satisfied: | |
3008 | ||
3009 | 1. The basic block has low register pressure. | |
3010 | 2. Register pressure won't be increases after hoisting EXPR. | |
3011 | ||
3012 | Constant expressions is handled conservatively, because | |
3013 | hoisting constant expression aggressively results in worse | |
3014 | code. This decision is made by the observation of CSiBE | |
3015 | on ARM target, while it has no obvious effect on other | |
3016 | targets like x86, x86_64, mips and powerpc. */ | |
3017 | else if (CONST_INT_P (expr->expr) | |
3018 | || (BB_DATA (bb)->max_reg_pressure[pressure_class] | |
3019 | >= ira_class_hard_regs_num[pressure_class] | |
3020 | && decreased_pressure < *nregs)) | |
3021 | distance -= bb_size[bb->index]; | |
3022 | } | |
3023 | else | |
b11f0116 | 3024 | distance -= bb_size[bb->index]; |
20160347 MK |
3025 | |
3026 | if (distance <= 0) | |
3027 | return 0; | |
3028 | } | |
3029 | else | |
3030 | gcc_assert (distance == 0); | |
bb457bd9 JL |
3031 | |
3032 | if (visited == NULL) | |
3033 | { | |
8e42ace1 | 3034 | visited_allocated_locally = 1; |
8cba9a05 | 3035 | visited = sbitmap_alloc (last_basic_block); |
f61e445a | 3036 | bitmap_clear (visited); |
bb457bd9 JL |
3037 | } |
3038 | ||
628f6a4e | 3039 | FOR_EACH_EDGE (pred, ei, bb->preds) |
bb457bd9 | 3040 | { |
e2d2ed72 | 3041 | basic_block pred_bb = pred->src; |
bb457bd9 JL |
3042 | |
3043 | if (pred->src == ENTRY_BLOCK_PTR) | |
3044 | break; | |
f305679f JH |
3045 | else if (pred_bb == expr_bb) |
3046 | continue; | |
d7c028c0 | 3047 | else if (bitmap_bit_p (visited, pred_bb->index)) |
bb457bd9 | 3048 | continue; |
d7c028c0 | 3049 | else if (! bitmap_bit_p (transp[pred_bb->index], expr->bitmap_index)) |
bb457bd9 JL |
3050 | break; |
3051 | /* Not killed. */ | |
3052 | else | |
3053 | { | |
d7c028c0 | 3054 | bitmap_set_bit (visited, pred_bb->index); |
b11f0116 BC |
3055 | if (! should_hoist_expr_to_dom (expr_bb, expr, pred_bb, |
3056 | visited, distance, bb_size, | |
4b8181c5 BC |
3057 | pressure_class, nregs, |
3058 | hoisted_bbs, from)) | |
bb457bd9 JL |
3059 | break; |
3060 | } | |
3061 | } | |
589005ff | 3062 | if (visited_allocated_locally) |
b11f0116 BC |
3063 | { |
3064 | /* If EXPR can be hoisted to expr_bb, record basic blocks through | |
4b8181c5 | 3065 | which EXPR is hoisted in hoisted_bbs. */ |
b11f0116 BC |
3066 | if (flag_ira_hoist_pressure && !pred) |
3067 | { | |
4b8181c5 BC |
3068 | /* Record the basic block from which EXPR is hoisted. */ |
3069 | bitmap_set_bit (visited, bb->index); | |
d4ac4ce2 | 3070 | EXECUTE_IF_SET_IN_BITMAP (visited, 0, i, sbi) |
4b8181c5 | 3071 | bitmap_set_bit (hoisted_bbs, i); |
b11f0116 BC |
3072 | } |
3073 | sbitmap_free (visited); | |
3074 | } | |
c4c81601 | 3075 | |
bb457bd9 JL |
3076 | return (pred == NULL); |
3077 | } | |
3078 | \f | |
073a8998 | 3079 | /* Find occurrence in BB. */ |
43c8a043 | 3080 | |
20160347 MK |
3081 | static struct occr * |
3082 | find_occr_in_bb (struct occr *occr, basic_block bb) | |
3083 | { | |
3084 | /* Find the right occurrence of this expression. */ | |
3085 | while (occr && BLOCK_FOR_INSN (occr->insn) != bb) | |
3086 | occr = occr->next; | |
3087 | ||
3088 | return occr; | |
3089 | } | |
3090 | ||
b11f0116 BC |
3091 | /* Actually perform code hoisting. |
3092 | ||
3093 | The code hoisting pass can hoist multiple computations of the same | |
3094 | expression along dominated path to a dominating basic block, like | |
3095 | from b2/b3 to b1 as depicted below: | |
3096 | ||
3097 | b1 ------ | |
3098 | /\ | | |
3099 | / \ | | |
3100 | bx by distance | |
3101 | / \ | | |
3102 | / \ | | |
3103 | b2 b3 ------ | |
3104 | ||
3105 | Unfortunately code hoisting generally extends the live range of an | |
3106 | output pseudo register, which increases register pressure and hurts | |
3107 | register allocation. To address this issue, an attribute MAX_DISTANCE | |
3108 | is computed and attached to each expression. The attribute is computed | |
3109 | from rtx cost of the corresponding expression and it's used to control | |
3110 | how long the expression can be hoisted up in flow graph. As the | |
3111 | expression is hoisted up in flow graph, GCC decreases its DISTANCE | |
4b8181c5 BC |
3112 | and stops the hoist if DISTANCE reaches 0. Code hoisting can decrease |
3113 | register pressure if live ranges of inputs are shrunk. | |
b11f0116 BC |
3114 | |
3115 | Option "-fira-hoist-pressure" implements register pressure directed | |
3116 | hoist based on upper method. The rationale is: | |
3117 | 1. Calculate register pressure for each basic block by reusing IRA | |
3118 | facility. | |
3119 | 2. When expression is hoisted through one basic block, GCC checks | |
4b8181c5 BC |
3120 | the change of live ranges for inputs/output. The basic block's |
3121 | register pressure will be increased because of extended live | |
3122 | range of output. However, register pressure will be decreased | |
3123 | if the live ranges of inputs are shrunk. | |
3124 | 3. After knowing how hoisting affects register pressure, GCC prefers | |
3125 | to hoist the expression if it can decrease register pressure, by | |
3126 | increasing DISTANCE of the corresponding expression. | |
3127 | 4. If hoisting the expression increases register pressure, GCC checks | |
3128 | register pressure of the basic block and decrease DISTANCE only if | |
3129 | the register pressure is high. In other words, expression will be | |
3130 | hoisted through at no cost if the basic block has low register | |
3131 | pressure. | |
3132 | 5. Update register pressure information for basic blocks through | |
3133 | which expression is hoisted. */ | |
c4c81601 | 3134 | |
5f39ad47 | 3135 | static int |
1d088dee | 3136 | hoist_code (void) |
bb457bd9 | 3137 | { |
e0082a72 | 3138 | basic_block bb, dominated; |
9771b263 | 3139 | vec<basic_block> dom_tree_walk; |
cad9aa15 | 3140 | unsigned int dom_tree_walk_index; |
9771b263 | 3141 | vec<basic_block> domby; |
b11f0116 | 3142 | unsigned int i, j, k; |
bb457bd9 | 3143 | struct expr **index_map; |
c4c81601 | 3144 | struct expr *expr; |
20160347 MK |
3145 | int *to_bb_head; |
3146 | int *bb_size; | |
5f39ad47 | 3147 | int changed = 0; |
b11f0116 BC |
3148 | struct bb_data *data; |
3149 | /* Basic blocks that have occurrences reachable from BB. */ | |
3150 | bitmap from_bbs; | |
3151 | /* Basic blocks through which expr is hoisted. */ | |
3152 | bitmap hoisted_bbs = NULL; | |
3153 | bitmap_iterator bi; | |
bb457bd9 | 3154 | |
bb457bd9 JL |
3155 | /* Compute a mapping from expression number (`bitmap_index') to |
3156 | hash table entry. */ | |
3157 | ||
5ed6ace5 | 3158 | index_map = XCNEWVEC (struct expr *, expr_hash_table.n_elems); |
02280659 | 3159 | for (i = 0; i < expr_hash_table.size; i++) |
43c8a043 | 3160 | for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash) |
c4c81601 | 3161 | index_map[expr->bitmap_index] = expr; |
bb457bd9 | 3162 | |
20160347 MK |
3163 | /* Calculate sizes of basic blocks and note how far |
3164 | each instruction is from the start of its block. We then use this | |
3165 | data to restrict distance an expression can travel. */ | |
3166 | ||
3167 | to_bb_head = XCNEWVEC (int, get_max_uid ()); | |
3168 | bb_size = XCNEWVEC (int, last_basic_block); | |
3169 | ||
3170 | FOR_EACH_BB (bb) | |
3171 | { | |
3172 | rtx insn; | |
20160347 MK |
3173 | int to_head; |
3174 | ||
20160347 | 3175 | to_head = 0; |
05b5ea34 | 3176 | FOR_BB_INSNS (bb, insn) |
20160347 MK |
3177 | { |
3178 | /* Don't count debug instructions to avoid them affecting | |
3179 | decision choices. */ | |
3180 | if (NONDEBUG_INSN_P (insn)) | |
3181 | to_bb_head[INSN_UID (insn)] = to_head++; | |
20160347 MK |
3182 | } |
3183 | ||
3184 | bb_size[bb->index] = to_head; | |
3185 | } | |
3186 | ||
cad9aa15 MK |
3187 | gcc_assert (EDGE_COUNT (ENTRY_BLOCK_PTR->succs) == 1 |
3188 | && (EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->dest | |
3189 | == ENTRY_BLOCK_PTR->next_bb)); | |
3190 | ||
b11f0116 BC |
3191 | from_bbs = BITMAP_ALLOC (NULL); |
3192 | if (flag_ira_hoist_pressure) | |
3193 | hoisted_bbs = BITMAP_ALLOC (NULL); | |
3194 | ||
cad9aa15 MK |
3195 | dom_tree_walk = get_all_dominated_blocks (CDI_DOMINATORS, |
3196 | ENTRY_BLOCK_PTR->next_bb); | |
3197 | ||
bb457bd9 JL |
3198 | /* Walk over each basic block looking for potentially hoistable |
3199 | expressions, nothing gets hoisted from the entry block. */ | |
9771b263 | 3200 | FOR_EACH_VEC_ELT (dom_tree_walk, dom_tree_walk_index, bb) |
bb457bd9 | 3201 | { |
cad9aa15 MK |
3202 | domby = get_dominated_to_depth (CDI_DOMINATORS, bb, MAX_HOIST_DEPTH); |
3203 | ||
9771b263 | 3204 | if (domby.length () == 0) |
cad9aa15 | 3205 | continue; |
bb457bd9 JL |
3206 | |
3207 | /* Examine each expression that is very busy at the exit of this | |
3208 | block. These are the potentially hoistable expressions. */ | |
5829cc0f | 3209 | for (i = 0; i < SBITMAP_SIZE (hoist_vbeout[bb->index]); i++) |
bb457bd9 | 3210 | { |
d7c028c0 | 3211 | if (bitmap_bit_p (hoist_vbeout[bb->index], i)) |
bb457bd9 | 3212 | { |
b11f0116 BC |
3213 | int nregs = 0; |
3214 | enum reg_class pressure_class = NO_REGS; | |
cad9aa15 MK |
3215 | /* Current expression. */ |
3216 | struct expr *expr = index_map[i]; | |
073a8998 | 3217 | /* Number of occurrences of EXPR that can be hoisted to BB. */ |
cad9aa15 | 3218 | int hoistable = 0; |
073a8998 | 3219 | /* Occurrences reachable from BB. */ |
6e1aa848 | 3220 | vec<occr_t> occrs_to_hoist = vNULL; |
cad9aa15 MK |
3221 | /* We want to insert the expression into BB only once, so |
3222 | note when we've inserted it. */ | |
3223 | int insn_inserted_p; | |
3224 | occr_t occr; | |
3225 | ||
ce4c0015 | 3226 | /* If an expression is computed in BB and is available at end of |
073a8998 | 3227 | BB, hoist all occurrences dominated by BB to BB. */ |
d7c028c0 | 3228 | if (bitmap_bit_p (comp[bb->index], i)) |
cad9aa15 MK |
3229 | { |
3230 | occr = find_occr_in_bb (expr->antic_occr, bb); | |
3231 | ||
3232 | if (occr) | |
3233 | { | |
073a8998 | 3234 | /* An occurrence might've been already deleted |
cad9aa15 | 3235 | while processing a dominator of BB. */ |
2d36b47f | 3236 | if (!occr->deleted_p) |
cad9aa15 MK |
3237 | { |
3238 | gcc_assert (NONDEBUG_INSN_P (occr->insn)); | |
3239 | hoistable++; | |
3240 | } | |
3241 | } | |
3242 | else | |
3243 | hoistable++; | |
3244 | } | |
ce4c0015 | 3245 | |
bb457bd9 JL |
3246 | /* We've found a potentially hoistable expression, now |
3247 | we look at every block BB dominates to see if it | |
3248 | computes the expression. */ | |
9771b263 | 3249 | FOR_EACH_VEC_ELT (domby, j, dominated) |
bb457bd9 | 3250 | { |
20160347 MK |
3251 | int max_distance; |
3252 | ||
bb457bd9 | 3253 | /* Ignore self dominance. */ |
c635a1ec | 3254 | if (bb == dominated) |
bb457bd9 | 3255 | continue; |
bb457bd9 JL |
3256 | /* We've found a dominated block, now see if it computes |
3257 | the busy expression and whether or not moving that | |
3258 | expression to the "beginning" of that block is safe. */ | |
d7c028c0 | 3259 | if (!bitmap_bit_p (antloc[dominated->index], i)) |
bb457bd9 JL |
3260 | continue; |
3261 | ||
cad9aa15 MK |
3262 | occr = find_occr_in_bb (expr->antic_occr, dominated); |
3263 | gcc_assert (occr); | |
20160347 | 3264 | |
073a8998 | 3265 | /* An occurrence might've been already deleted |
cad9aa15 MK |
3266 | while processing a dominator of BB. */ |
3267 | if (occr->deleted_p) | |
2d36b47f | 3268 | continue; |
cad9aa15 MK |
3269 | gcc_assert (NONDEBUG_INSN_P (occr->insn)); |
3270 | ||
3271 | max_distance = expr->max_distance; | |
3272 | if (max_distance > 0) | |
3273 | /* Adjust MAX_DISTANCE to account for the fact that | |
3274 | OCCR won't have to travel all of DOMINATED, but | |
3275 | only part of it. */ | |
3276 | max_distance += (bb_size[dominated->index] | |
3277 | - to_bb_head[INSN_UID (occr->insn)]); | |
20160347 | 3278 | |
b11f0116 BC |
3279 | pressure_class = get_pressure_class_and_nregs (occr->insn, |
3280 | &nregs); | |
3281 | ||
3282 | /* Note if the expression should be hoisted from the dominated | |
3283 | block to BB if it can reach DOMINATED unimpared. | |
bb457bd9 JL |
3284 | |
3285 | Keep track of how many times this expression is hoistable | |
3286 | from a dominated block into BB. */ | |
b11f0116 BC |
3287 | if (should_hoist_expr_to_dom (bb, expr, dominated, NULL, |
3288 | max_distance, bb_size, | |
3289 | pressure_class, &nregs, | |
4b8181c5 | 3290 | hoisted_bbs, occr->insn)) |
cad9aa15 MK |
3291 | { |
3292 | hoistable++; | |
9771b263 | 3293 | occrs_to_hoist.safe_push (occr); |
cad9aa15 MK |
3294 | bitmap_set_bit (from_bbs, dominated->index); |
3295 | } | |
bb457bd9 JL |
3296 | } |
3297 | ||
ff7cc307 | 3298 | /* If we found more than one hoistable occurrence of this |
cad9aa15 | 3299 | expression, then note it in the vector of expressions to |
bb457bd9 JL |
3300 | hoist. It makes no sense to hoist things which are computed |
3301 | in only one BB, and doing so tends to pessimize register | |
3302 | allocation. One could increase this value to try harder | |
3303 | to avoid any possible code expansion due to register | |
3304 | allocation issues; however experiments have shown that | |
3305 | the vast majority of hoistable expressions are only movable | |
e0bb17a8 | 3306 | from two successors, so raising this threshold is likely |
bb457bd9 | 3307 | to nullify any benefit we get from code hoisting. */ |
62a3f636 | 3308 | if (hoistable > 1 && dbg_cnt (hoist_insn)) |
bb457bd9 | 3309 | { |
9771b263 | 3310 | /* If (hoistable != vec::length), then there is |
073a8998 | 3311 | an occurrence of EXPR in BB itself. Don't waste |
cad9aa15 | 3312 | time looking for LCA in this case. */ |
9771b263 | 3313 | if ((unsigned) hoistable == occrs_to_hoist.length ()) |
cad9aa15 MK |
3314 | { |
3315 | basic_block lca; | |
3316 | ||
3317 | lca = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
3318 | from_bbs); | |
3319 | if (lca != bb) | |
073a8998 | 3320 | /* Punt, it's better to hoist these occurrences to |
cad9aa15 | 3321 | LCA. */ |
9771b263 | 3322 | occrs_to_hoist.release (); |
cad9aa15 | 3323 | } |
bb457bd9 | 3324 | } |
cad9aa15 | 3325 | else |
688010ba | 3326 | /* Punt, no point hoisting a single occurrence. */ |
9771b263 | 3327 | occrs_to_hoist.release (); |
bb457bd9 | 3328 | |
b11f0116 | 3329 | if (flag_ira_hoist_pressure |
9771b263 | 3330 | && !occrs_to_hoist.is_empty ()) |
b11f0116 | 3331 | { |
4b8181c5 BC |
3332 | /* Increase register pressure of basic blocks to which |
3333 | expr is hoisted because of extended live range of | |
3334 | output. */ | |
b11f0116 BC |
3335 | data = BB_DATA (bb); |
3336 | data->max_reg_pressure[pressure_class] += nregs; | |
4b8181c5 BC |
3337 | EXECUTE_IF_SET_IN_BITMAP (hoisted_bbs, 0, k, bi) |
3338 | { | |
3339 | data = BB_DATA (BASIC_BLOCK (k)); | |
3340 | data->max_reg_pressure[pressure_class] += nregs; | |
3341 | } | |
b11f0116 BC |
3342 | } |
3343 | else if (flag_ira_hoist_pressure) | |
3344 | { | |
4b8181c5 BC |
3345 | /* Restore register pressure and live_in info for basic |
3346 | blocks recorded in hoisted_bbs when expr will not be | |
3347 | hoisted. */ | |
b11f0116 BC |
3348 | EXECUTE_IF_SET_IN_BITMAP (hoisted_bbs, 0, k, bi) |
3349 | { | |
3350 | data = BB_DATA (BASIC_BLOCK (k)); | |
4b8181c5 BC |
3351 | bitmap_copy (data->live_in, data->backup); |
3352 | data->max_reg_pressure[pressure_class] | |
3353 | = data->old_pressure; | |
b11f0116 BC |
3354 | } |
3355 | } | |
3356 | ||
3357 | if (flag_ira_hoist_pressure) | |
3358 | bitmap_clear (hoisted_bbs); | |
3359 | ||
cad9aa15 | 3360 | insn_inserted_p = 0; |
bb457bd9 | 3361 | |
073a8998 | 3362 | /* Walk through occurrences of I'th expressions we want |
cad9aa15 | 3363 | to hoist to BB and make the transformations. */ |
9771b263 | 3364 | FOR_EACH_VEC_ELT (occrs_to_hoist, j, occr) |
bb457bd9 | 3365 | { |
cad9aa15 MK |
3366 | rtx insn; |
3367 | rtx set; | |
3368 | ||
3369 | gcc_assert (!occr->deleted_p); | |
3370 | ||
3371 | insn = occr->insn; | |
3372 | set = single_set (insn); | |
3373 | gcc_assert (set); | |
3374 | ||
3375 | /* Create a pseudo-reg to store the result of reaching | |
3376 | expressions into. Get the mode for the new pseudo | |
3377 | from the mode of the original destination pseudo. | |
3378 | ||
3379 | It is important to use new pseudos whenever we | |
3380 | emit a set. This will allow reload to use | |
3381 | rematerialization for such registers. */ | |
3382 | if (!insn_inserted_p) | |
3383 | expr->reaching_reg | |
3384 | = gen_reg_rtx_and_attrs (SET_DEST (set)); | |
3385 | ||
43c8a043 | 3386 | gcse_emit_move_after (SET_DEST (set), expr->reaching_reg, |
cad9aa15 MK |
3387 | insn); |
3388 | delete_insn (insn); | |
3389 | occr->deleted_p = 1; | |
3390 | changed = 1; | |
3391 | gcse_subst_count++; | |
3392 | ||
3393 | if (!insn_inserted_p) | |
bb457bd9 | 3394 | { |
cad9aa15 MK |
3395 | insert_insn_end_basic_block (expr, bb); |
3396 | insn_inserted_p = 1; | |
bb457bd9 JL |
3397 | } |
3398 | } | |
cad9aa15 | 3399 | |
9771b263 | 3400 | occrs_to_hoist.release (); |
cad9aa15 | 3401 | bitmap_clear (from_bbs); |
bb457bd9 JL |
3402 | } |
3403 | } | |
9771b263 | 3404 | domby.release (); |
bb457bd9 | 3405 | } |
c4c81601 | 3406 | |
9771b263 | 3407 | dom_tree_walk.release (); |
b11f0116 BC |
3408 | BITMAP_FREE (from_bbs); |
3409 | if (flag_ira_hoist_pressure) | |
3410 | BITMAP_FREE (hoisted_bbs); | |
3411 | ||
20160347 MK |
3412 | free (bb_size); |
3413 | free (to_bb_head); | |
8e42ace1 | 3414 | free (index_map); |
5f39ad47 SB |
3415 | |
3416 | return changed; | |
bb457bd9 JL |
3417 | } |
3418 | ||
b11f0116 BC |
3419 | /* Return pressure class and number of needed hard registers (through |
3420 | *NREGS) of register REGNO. */ | |
3421 | static enum reg_class | |
3422 | get_regno_pressure_class (int regno, int *nregs) | |
3423 | { | |
3424 | if (regno >= FIRST_PSEUDO_REGISTER) | |
3425 | { | |
3426 | enum reg_class pressure_class; | |
3427 | ||
3428 | pressure_class = reg_allocno_class (regno); | |
3429 | pressure_class = ira_pressure_class_translate[pressure_class]; | |
3430 | *nregs | |
3431 | = ira_reg_class_max_nregs[pressure_class][PSEUDO_REGNO_MODE (regno)]; | |
3432 | return pressure_class; | |
3433 | } | |
3434 | else if (! TEST_HARD_REG_BIT (ira_no_alloc_regs, regno) | |
3435 | && ! TEST_HARD_REG_BIT (eliminable_regset, regno)) | |
3436 | { | |
3437 | *nregs = 1; | |
3438 | return ira_pressure_class_translate[REGNO_REG_CLASS (regno)]; | |
3439 | } | |
3440 | else | |
3441 | { | |
3442 | *nregs = 0; | |
3443 | return NO_REGS; | |
3444 | } | |
3445 | } | |
3446 | ||
3447 | /* Return pressure class and number of hard registers (through *NREGS) | |
3448 | for destination of INSN. */ | |
3449 | static enum reg_class | |
3450 | get_pressure_class_and_nregs (rtx insn, int *nregs) | |
3451 | { | |
3452 | rtx reg; | |
3453 | enum reg_class pressure_class; | |
3454 | rtx set = single_set (insn); | |
3455 | ||
3456 | /* Considered invariant insns have only one set. */ | |
3457 | gcc_assert (set != NULL_RTX); | |
3458 | reg = SET_DEST (set); | |
3459 | if (GET_CODE (reg) == SUBREG) | |
3460 | reg = SUBREG_REG (reg); | |
3461 | if (MEM_P (reg)) | |
3462 | { | |
3463 | *nregs = 0; | |
3464 | pressure_class = NO_REGS; | |
3465 | } | |
3466 | else | |
3467 | { | |
3468 | gcc_assert (REG_P (reg)); | |
3469 | pressure_class = reg_allocno_class (REGNO (reg)); | |
3470 | pressure_class = ira_pressure_class_translate[pressure_class]; | |
3471 | *nregs | |
3472 | = ira_reg_class_max_nregs[pressure_class][GET_MODE (SET_SRC (set))]; | |
3473 | } | |
3474 | return pressure_class; | |
3475 | } | |
3476 | ||
3477 | /* Increase (if INCR_P) or decrease current register pressure for | |
3478 | register REGNO. */ | |
3479 | static void | |
3480 | change_pressure (int regno, bool incr_p) | |
3481 | { | |
3482 | int nregs; | |
3483 | enum reg_class pressure_class; | |
3484 | ||
3485 | pressure_class = get_regno_pressure_class (regno, &nregs); | |
3486 | if (! incr_p) | |
3487 | curr_reg_pressure[pressure_class] -= nregs; | |
3488 | else | |
3489 | { | |
3490 | curr_reg_pressure[pressure_class] += nregs; | |
3491 | if (BB_DATA (curr_bb)->max_reg_pressure[pressure_class] | |
3492 | < curr_reg_pressure[pressure_class]) | |
3493 | BB_DATA (curr_bb)->max_reg_pressure[pressure_class] | |
3494 | = curr_reg_pressure[pressure_class]; | |
3495 | } | |
3496 | } | |
3497 | ||
3498 | /* Calculate register pressure for each basic block by walking insns | |
3499 | from last to first. */ | |
3500 | static void | |
3501 | calculate_bb_reg_pressure (void) | |
3502 | { | |
3503 | int i; | |
3504 | unsigned int j; | |
3505 | rtx insn; | |
3506 | basic_block bb; | |
3507 | bitmap curr_regs_live; | |
3508 | bitmap_iterator bi; | |
3509 | ||
3510 | ||
55a2c322 | 3511 | ira_setup_eliminable_regset (false); |
b11f0116 BC |
3512 | curr_regs_live = BITMAP_ALLOC (®_obstack); |
3513 | FOR_EACH_BB (bb) | |
3514 | { | |
3515 | curr_bb = bb; | |
4b8181c5 BC |
3516 | BB_DATA (bb)->live_in = BITMAP_ALLOC (NULL); |
3517 | BB_DATA (bb)->backup = BITMAP_ALLOC (NULL); | |
3518 | bitmap_copy (BB_DATA (bb)->live_in, df_get_live_in (bb)); | |
3519 | bitmap_copy (curr_regs_live, df_get_live_out (bb)); | |
b11f0116 BC |
3520 | for (i = 0; i < ira_pressure_classes_num; i++) |
3521 | curr_reg_pressure[ira_pressure_classes[i]] = 0; | |
3522 | EXECUTE_IF_SET_IN_BITMAP (curr_regs_live, 0, j, bi) | |
3523 | change_pressure (j, true); | |
3524 | ||
3525 | FOR_BB_INSNS_REVERSE (bb, insn) | |
3526 | { | |
3527 | rtx dreg; | |
3528 | int regno; | |
3529 | df_ref *def_rec, *use_rec; | |
3530 | ||
3531 | if (! NONDEBUG_INSN_P (insn)) | |
3532 | continue; | |
3533 | ||
3534 | for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++) | |
3535 | { | |
3536 | dreg = DF_REF_REAL_REG (*def_rec); | |
3537 | gcc_assert (REG_P (dreg)); | |
3538 | regno = REGNO (dreg); | |
3539 | if (!(DF_REF_FLAGS (*def_rec) | |
3540 | & (DF_REF_PARTIAL | DF_REF_CONDITIONAL))) | |
3541 | { | |
3542 | if (bitmap_clear_bit (curr_regs_live, regno)) | |
3543 | change_pressure (regno, false); | |
3544 | } | |
3545 | } | |
3546 | ||
3547 | for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++) | |
3548 | { | |
3549 | dreg = DF_REF_REAL_REG (*use_rec); | |
3550 | gcc_assert (REG_P (dreg)); | |
3551 | regno = REGNO (dreg); | |
3552 | if (bitmap_set_bit (curr_regs_live, regno)) | |
3553 | change_pressure (regno, true); | |
3554 | } | |
3555 | } | |
3556 | } | |
3557 | BITMAP_FREE (curr_regs_live); | |
3558 | ||
3559 | if (dump_file == NULL) | |
3560 | return; | |
3561 | ||
3562 | fprintf (dump_file, "\nRegister Pressure: \n"); | |
3563 | FOR_EACH_BB (bb) | |
3564 | { | |
3565 | fprintf (dump_file, " Basic block %d: \n", bb->index); | |
3566 | for (i = 0; (int) i < ira_pressure_classes_num; i++) | |
3567 | { | |
3568 | enum reg_class pressure_class; | |
3569 | ||
3570 | pressure_class = ira_pressure_classes[i]; | |
3571 | if (BB_DATA (bb)->max_reg_pressure[pressure_class] == 0) | |
3572 | continue; | |
3573 | ||
3574 | fprintf (dump_file, " %s=%d\n", reg_class_names[pressure_class], | |
3575 | BB_DATA (bb)->max_reg_pressure[pressure_class]); | |
3576 | } | |
3577 | } | |
3578 | fprintf (dump_file, "\n"); | |
3579 | } | |
3580 | ||
bb457bd9 JL |
3581 | /* Top level routine to perform one code hoisting (aka unification) pass |
3582 | ||
cc2902df | 3583 | Return nonzero if a change was made. */ |
bb457bd9 JL |
3584 | |
3585 | static int | |
1d088dee | 3586 | one_code_hoisting_pass (void) |
bb457bd9 JL |
3587 | { |
3588 | int changed = 0; | |
3589 | ||
5f39ad47 SB |
3590 | gcse_subst_count = 0; |
3591 | gcse_create_count = 0; | |
3592 | ||
3593 | /* Return if there's nothing to do, or it is too expensive. */ | |
3594 | if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1 | |
3595 | || is_too_expensive (_("GCSE disabled"))) | |
3596 | return 0; | |
3597 | ||
20160347 MK |
3598 | doing_code_hoisting_p = true; |
3599 | ||
b11f0116 BC |
3600 | /* Calculate register pressure for each basic block. */ |
3601 | if (flag_ira_hoist_pressure) | |
3602 | { | |
3603 | regstat_init_n_sets_and_refs (); | |
3604 | ira_set_pseudo_classes (false, dump_file); | |
3605 | alloc_aux_for_blocks (sizeof (struct bb_data)); | |
3606 | calculate_bb_reg_pressure (); | |
3607 | regstat_free_n_sets_and_refs (); | |
3608 | } | |
3609 | ||
5f39ad47 SB |
3610 | /* We need alias. */ |
3611 | init_alias_analysis (); | |
3612 | ||
3613 | bytes_used = 0; | |
3614 | gcc_obstack_init (&gcse_obstack); | |
3615 | alloc_gcse_mem (); | |
3616 | ||
e45425ec | 3617 | alloc_hash_table (&expr_hash_table); |
02280659 | 3618 | compute_hash_table (&expr_hash_table); |
10d22567 ZD |
3619 | if (dump_file) |
3620 | dump_hash_table (dump_file, "Code Hosting Expressions", &expr_hash_table); | |
c4c81601 | 3621 | |
02280659 | 3622 | if (expr_hash_table.n_elems > 0) |
bb457bd9 | 3623 | { |
02280659 | 3624 | alloc_code_hoist_mem (last_basic_block, expr_hash_table.n_elems); |
bb457bd9 | 3625 | compute_code_hoist_data (); |
5f39ad47 | 3626 | changed = hoist_code (); |
bb457bd9 JL |
3627 | free_code_hoist_mem (); |
3628 | } | |
c4c81601 | 3629 | |
b11f0116 BC |
3630 | if (flag_ira_hoist_pressure) |
3631 | { | |
3632 | free_aux_for_blocks (); | |
3633 | free_reg_info (); | |
3634 | } | |
02280659 | 3635 | free_hash_table (&expr_hash_table); |
5f39ad47 SB |
3636 | free_gcse_mem (); |
3637 | obstack_free (&gcse_obstack, NULL); | |
3638 | ||
3639 | /* We are finished with alias. */ | |
3640 | end_alias_analysis (); | |
3641 | ||
3642 | if (dump_file) | |
3643 | { | |
3644 | fprintf (dump_file, "HOIST of %s, %d basic blocks, %d bytes needed, ", | |
3645 | current_function_name (), n_basic_blocks, bytes_used); | |
3646 | fprintf (dump_file, "%d substs, %d insns created\n", | |
3647 | gcse_subst_count, gcse_create_count); | |
3648 | } | |
bb457bd9 | 3649 | |
20160347 MK |
3650 | doing_code_hoisting_p = false; |
3651 | ||
bb457bd9 JL |
3652 | return changed; |
3653 | } | |
a13d4ebf | 3654 | \f |
43c8a043 EB |
3655 | /* Here we provide the things required to do store motion towards the exit. |
3656 | In order for this to be effective, gcse also needed to be taught how to | |
3657 | move a load when it is killed only by a store to itself. | |
a13d4ebf AM |
3658 | |
3659 | int i; | |
3660 | float a[10]; | |
3661 | ||
3662 | void foo(float scale) | |
3663 | { | |
3664 | for (i=0; i<10; i++) | |
3665 | a[i] *= scale; | |
3666 | } | |
3667 | ||
3668 | 'i' is both loaded and stored to in the loop. Normally, gcse cannot move | |
589005ff KH |
3669 | the load out since its live around the loop, and stored at the bottom |
3670 | of the loop. | |
a13d4ebf | 3671 | |
589005ff | 3672 | The 'Load Motion' referred to and implemented in this file is |
43c8a043 | 3673 | an enhancement to gcse which when using edge based LCM, recognizes |
a13d4ebf AM |
3674 | this situation and allows gcse to move the load out of the loop. |
3675 | ||
3676 | Once gcse has hoisted the load, store motion can then push this | |
3677 | load towards the exit, and we end up with no loads or stores of 'i' | |
3678 | in the loop. */ | |
3679 | ||
ff7cc307 | 3680 | /* This will search the ldst list for a matching expression. If it |
a13d4ebf AM |
3681 | doesn't find one, we create one and initialize it. */ |
3682 | ||
3683 | static struct ls_expr * | |
1d088dee | 3684 | ldst_entry (rtx x) |
a13d4ebf | 3685 | { |
b58b21d5 | 3686 | int do_not_record_p = 0; |
a13d4ebf | 3687 | struct ls_expr * ptr; |
b58b21d5 | 3688 | unsigned int hash; |
4a8fb1a1 | 3689 | ls_expr **slot; |
9727e468 | 3690 | struct ls_expr e; |
a13d4ebf | 3691 | |
0516f6fe SB |
3692 | hash = hash_rtx (x, GET_MODE (x), &do_not_record_p, |
3693 | NULL, /*have_reg_qty=*/false); | |
a13d4ebf | 3694 | |
9727e468 | 3695 | e.pattern = x; |
4a8fb1a1 | 3696 | slot = pre_ldst_table.find_slot_with_hash (&e, hash, INSERT); |
9727e468 | 3697 | if (*slot) |
4a8fb1a1 | 3698 | return *slot; |
b58b21d5 | 3699 | |
5ed6ace5 | 3700 | ptr = XNEW (struct ls_expr); |
b58b21d5 RS |
3701 | |
3702 | ptr->next = pre_ldst_mems; | |
3703 | ptr->expr = NULL; | |
3704 | ptr->pattern = x; | |
3705 | ptr->pattern_regs = NULL_RTX; | |
3706 | ptr->loads = NULL_RTX; | |
3707 | ptr->stores = NULL_RTX; | |
3708 | ptr->reaching_reg = NULL_RTX; | |
3709 | ptr->invalid = 0; | |
3710 | ptr->index = 0; | |
3711 | ptr->hash_index = hash; | |
3712 | pre_ldst_mems = ptr; | |
9727e468 | 3713 | *slot = ptr; |
589005ff | 3714 | |
a13d4ebf AM |
3715 | return ptr; |
3716 | } | |
3717 | ||
3718 | /* Free up an individual ldst entry. */ | |
3719 | ||
589005ff | 3720 | static void |
1d088dee | 3721 | free_ldst_entry (struct ls_expr * ptr) |
a13d4ebf | 3722 | { |
aaa4ca30 AJ |
3723 | free_INSN_LIST_list (& ptr->loads); |
3724 | free_INSN_LIST_list (& ptr->stores); | |
a13d4ebf AM |
3725 | |
3726 | free (ptr); | |
3727 | } | |
3728 | ||
3729 | /* Free up all memory associated with the ldst list. */ | |
3730 | ||
3731 | static void | |
43c8a043 | 3732 | free_ld_motion_mems (void) |
a13d4ebf | 3733 | { |
4a8fb1a1 LC |
3734 | if (pre_ldst_table.is_created ()) |
3735 | pre_ldst_table.dispose (); | |
9727e468 | 3736 | |
589005ff | 3737 | while (pre_ldst_mems) |
a13d4ebf AM |
3738 | { |
3739 | struct ls_expr * tmp = pre_ldst_mems; | |
3740 | ||
3741 | pre_ldst_mems = pre_ldst_mems->next; | |
3742 | ||
3743 | free_ldst_entry (tmp); | |
3744 | } | |
3745 | ||
3746 | pre_ldst_mems = NULL; | |
3747 | } | |
3748 | ||
3749 | /* Dump debugging info about the ldst list. */ | |
3750 | ||
3751 | static void | |
1d088dee | 3752 | print_ldst_list (FILE * file) |
a13d4ebf AM |
3753 | { |
3754 | struct ls_expr * ptr; | |
3755 | ||
3756 | fprintf (file, "LDST list: \n"); | |
3757 | ||
43c8a043 | 3758 | for (ptr = pre_ldst_mems; ptr != NULL; ptr = ptr->next) |
a13d4ebf AM |
3759 | { |
3760 | fprintf (file, " Pattern (%3d): ", ptr->index); | |
3761 | ||
3762 | print_rtl (file, ptr->pattern); | |
3763 | ||
3764 | fprintf (file, "\n Loads : "); | |
3765 | ||
3766 | if (ptr->loads) | |
3767 | print_rtl (file, ptr->loads); | |
3768 | else | |
3769 | fprintf (file, "(nil)"); | |
3770 | ||
3771 | fprintf (file, "\n Stores : "); | |
3772 | ||
3773 | if (ptr->stores) | |
3774 | print_rtl (file, ptr->stores); | |
3775 | else | |
3776 | fprintf (file, "(nil)"); | |
3777 | ||
3778 | fprintf (file, "\n\n"); | |
3779 | } | |
3780 | ||
3781 | fprintf (file, "\n"); | |
3782 | } | |
3783 | ||
3784 | /* Returns 1 if X is in the list of ldst only expressions. */ | |
3785 | ||
3786 | static struct ls_expr * | |
1d088dee | 3787 | find_rtx_in_ldst (rtx x) |
a13d4ebf | 3788 | { |
9727e468 | 3789 | struct ls_expr e; |
4a8fb1a1 LC |
3790 | ls_expr **slot; |
3791 | if (!pre_ldst_table.is_created ()) | |
6375779a | 3792 | return NULL; |
9727e468 | 3793 | e.pattern = x; |
4a8fb1a1 LC |
3794 | slot = pre_ldst_table.find_slot (&e, NO_INSERT); |
3795 | if (!slot || (*slot)->invalid) | |
9727e468 | 3796 | return NULL; |
4a8fb1a1 | 3797 | return *slot; |
a13d4ebf | 3798 | } |
a13d4ebf AM |
3799 | \f |
3800 | /* Load Motion for loads which only kill themselves. */ | |
3801 | ||
43c8a043 EB |
3802 | /* Return true if x, a MEM, is a simple access with no side effects. |
3803 | These are the types of loads we consider for the ld_motion list, | |
3804 | otherwise we let the usual aliasing take care of it. */ | |
a13d4ebf | 3805 | |
589005ff | 3806 | static int |
ed7a4b4b | 3807 | simple_mem (const_rtx x) |
a13d4ebf | 3808 | { |
a13d4ebf AM |
3809 | if (MEM_VOLATILE_P (x)) |
3810 | return 0; | |
589005ff | 3811 | |
a13d4ebf AM |
3812 | if (GET_MODE (x) == BLKmode) |
3813 | return 0; | |
aaa4ca30 | 3814 | |
47a3dae1 | 3815 | /* If we are handling exceptions, we must be careful with memory references |
8f4f502f | 3816 | that may trap. If we are not, the behavior is undefined, so we may just |
47a3dae1 | 3817 | continue. */ |
8f4f502f | 3818 | if (cfun->can_throw_non_call_exceptions && may_trap_p (x)) |
98d3d336 RS |
3819 | return 0; |
3820 | ||
47a3dae1 ZD |
3821 | if (side_effects_p (x)) |
3822 | return 0; | |
589005ff | 3823 | |
47a3dae1 ZD |
3824 | /* Do not consider function arguments passed on stack. */ |
3825 | if (reg_mentioned_p (stack_pointer_rtx, x)) | |
3826 | return 0; | |
3827 | ||
3828 | if (flag_float_store && FLOAT_MODE_P (GET_MODE (x))) | |
3829 | return 0; | |
3830 | ||
3831 | return 1; | |
a13d4ebf AM |
3832 | } |
3833 | ||
589005ff KH |
3834 | /* Make sure there isn't a buried reference in this pattern anywhere. |
3835 | If there is, invalidate the entry for it since we're not capable | |
3836 | of fixing it up just yet.. We have to be sure we know about ALL | |
a13d4ebf AM |
3837 | loads since the aliasing code will allow all entries in the |
3838 | ld_motion list to not-alias itself. If we miss a load, we will get | |
589005ff | 3839 | the wrong value since gcse might common it and we won't know to |
a13d4ebf AM |
3840 | fix it up. */ |
3841 | ||
3842 | static void | |
1d088dee | 3843 | invalidate_any_buried_refs (rtx x) |
a13d4ebf AM |
3844 | { |
3845 | const char * fmt; | |
8e42ace1 | 3846 | int i, j; |
a13d4ebf AM |
3847 | struct ls_expr * ptr; |
3848 | ||
3849 | /* Invalidate it in the list. */ | |
7b1b4aed | 3850 | if (MEM_P (x) && simple_mem (x)) |
a13d4ebf AM |
3851 | { |
3852 | ptr = ldst_entry (x); | |
3853 | ptr->invalid = 1; | |
3854 | } | |
3855 | ||
3856 | /* Recursively process the insn. */ | |
3857 | fmt = GET_RTX_FORMAT (GET_CODE (x)); | |
589005ff | 3858 | |
a13d4ebf AM |
3859 | for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--) |
3860 | { | |
3861 | if (fmt[i] == 'e') | |
3862 | invalidate_any_buried_refs (XEXP (x, i)); | |
3863 | else if (fmt[i] == 'E') | |
3864 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
3865 | invalidate_any_buried_refs (XVECEXP (x, i, j)); | |
3866 | } | |
3867 | } | |
3868 | ||
4d3eb89a HPN |
3869 | /* Find all the 'simple' MEMs which are used in LOADs and STORES. Simple |
3870 | being defined as MEM loads and stores to symbols, with no side effects | |
3871 | and no registers in the expression. For a MEM destination, we also | |
3872 | check that the insn is still valid if we replace the destination with a | |
3873 | REG, as is done in update_ld_motion_stores. If there are any uses/defs | |
3874 | which don't match this criteria, they are invalidated and trimmed out | |
3875 | later. */ | |
a13d4ebf | 3876 | |
589005ff | 3877 | static void |
1d088dee | 3878 | compute_ld_motion_mems (void) |
a13d4ebf AM |
3879 | { |
3880 | struct ls_expr * ptr; | |
e0082a72 | 3881 | basic_block bb; |
a13d4ebf | 3882 | rtx insn; |
589005ff | 3883 | |
a13d4ebf | 3884 | pre_ldst_mems = NULL; |
4a8fb1a1 | 3885 | pre_ldst_table.create (13); |
a13d4ebf | 3886 | |
e0082a72 | 3887 | FOR_EACH_BB (bb) |
a13d4ebf | 3888 | { |
eb232f4e | 3889 | FOR_BB_INSNS (bb, insn) |
a13d4ebf | 3890 | { |
b5b8b0ac | 3891 | if (NONDEBUG_INSN_P (insn)) |
a13d4ebf AM |
3892 | { |
3893 | if (GET_CODE (PATTERN (insn)) == SET) | |
3894 | { | |
3895 | rtx src = SET_SRC (PATTERN (insn)); | |
3896 | rtx dest = SET_DEST (PATTERN (insn)); | |
2df013f3 JB |
3897 | rtx note = find_reg_equal_equiv_note (insn); |
3898 | rtx src_eq; | |
a13d4ebf AM |
3899 | |
3900 | /* Check for a simple LOAD... */ | |
7b1b4aed | 3901 | if (MEM_P (src) && simple_mem (src)) |
a13d4ebf AM |
3902 | { |
3903 | ptr = ldst_entry (src); | |
7b1b4aed | 3904 | if (REG_P (dest)) |
a13d4ebf AM |
3905 | ptr->loads = alloc_INSN_LIST (insn, ptr->loads); |
3906 | else | |
3907 | ptr->invalid = 1; | |
3908 | } | |
3909 | else | |
3910 | { | |
3911 | /* Make sure there isn't a buried load somewhere. */ | |
3912 | invalidate_any_buried_refs (src); | |
3913 | } | |
589005ff | 3914 | |
2df013f3 JB |
3915 | if (note != 0 && REG_NOTE_KIND (note) == REG_EQUAL) |
3916 | src_eq = XEXP (note, 0); | |
3917 | else | |
3918 | src_eq = NULL_RTX; | |
3919 | ||
3920 | if (src_eq != NULL_RTX | |
3921 | && !(MEM_P (src_eq) && simple_mem (src_eq))) | |
3922 | invalidate_any_buried_refs (src_eq); | |
3923 | ||
a13d4ebf AM |
3924 | /* Check for stores. Don't worry about aliased ones, they |
3925 | will block any movement we might do later. We only care | |
3926 | about this exact pattern since those are the only | |
3927 | circumstance that we will ignore the aliasing info. */ | |
7b1b4aed | 3928 | if (MEM_P (dest) && simple_mem (dest)) |
a13d4ebf AM |
3929 | { |
3930 | ptr = ldst_entry (dest); | |
589005ff | 3931 | |
7b1b4aed | 3932 | if (! MEM_P (src) |
4d3eb89a HPN |
3933 | && GET_CODE (src) != ASM_OPERANDS |
3934 | /* Check for REG manually since want_to_gcse_p | |
3935 | returns 0 for all REGs. */ | |
df35c271 | 3936 | && can_assign_to_reg_without_clobbers_p (src)) |
a13d4ebf AM |
3937 | ptr->stores = alloc_INSN_LIST (insn, ptr->stores); |
3938 | else | |
3939 | ptr->invalid = 1; | |
3940 | } | |
3941 | } | |
3942 | else | |
3943 | invalidate_any_buried_refs (PATTERN (insn)); | |
3944 | } | |
3945 | } | |
3946 | } | |
3947 | } | |
3948 | ||
589005ff | 3949 | /* Remove any references that have been either invalidated or are not in the |
a13d4ebf AM |
3950 | expression list for pre gcse. */ |
3951 | ||
3952 | static void | |
1d088dee | 3953 | trim_ld_motion_mems (void) |
a13d4ebf | 3954 | { |
b58b21d5 RS |
3955 | struct ls_expr * * last = & pre_ldst_mems; |
3956 | struct ls_expr * ptr = pre_ldst_mems; | |
a13d4ebf AM |
3957 | |
3958 | while (ptr != NULL) | |
3959 | { | |
b58b21d5 | 3960 | struct expr * expr; |
589005ff | 3961 | |
a13d4ebf | 3962 | /* Delete if entry has been made invalid. */ |
b58b21d5 | 3963 | if (! ptr->invalid) |
a13d4ebf | 3964 | { |
a13d4ebf | 3965 | /* Delete if we cannot find this mem in the expression list. */ |
b58b21d5 | 3966 | unsigned int hash = ptr->hash_index % expr_hash_table.size; |
589005ff | 3967 | |
b58b21d5 RS |
3968 | for (expr = expr_hash_table.table[hash]; |
3969 | expr != NULL; | |
3970 | expr = expr->next_same_hash) | |
3971 | if (expr_equiv_p (expr->expr, ptr->pattern)) | |
3972 | break; | |
a13d4ebf AM |
3973 | } |
3974 | else | |
b58b21d5 RS |
3975 | expr = (struct expr *) 0; |
3976 | ||
3977 | if (expr) | |
a13d4ebf AM |
3978 | { |
3979 | /* Set the expression field if we are keeping it. */ | |
a13d4ebf | 3980 | ptr->expr = expr; |
b58b21d5 | 3981 | last = & ptr->next; |
a13d4ebf AM |
3982 | ptr = ptr->next; |
3983 | } | |
b58b21d5 RS |
3984 | else |
3985 | { | |
3986 | *last = ptr->next; | |
4a8fb1a1 | 3987 | pre_ldst_table.remove_elt_with_hash (ptr, ptr->hash_index); |
b58b21d5 RS |
3988 | free_ldst_entry (ptr); |
3989 | ptr = * last; | |
3990 | } | |
a13d4ebf AM |
3991 | } |
3992 | ||
3993 | /* Show the world what we've found. */ | |
10d22567 ZD |
3994 | if (dump_file && pre_ldst_mems != NULL) |
3995 | print_ldst_list (dump_file); | |
a13d4ebf AM |
3996 | } |
3997 | ||
3998 | /* This routine will take an expression which we are replacing with | |
3999 | a reaching register, and update any stores that are needed if | |
4000 | that expression is in the ld_motion list. Stores are updated by | |
a98ebe2e | 4001 | copying their SRC to the reaching register, and then storing |
a13d4ebf AM |
4002 | the reaching register into the store location. These keeps the |
4003 | correct value in the reaching register for the loads. */ | |
4004 | ||
4005 | static void | |
1d088dee | 4006 | update_ld_motion_stores (struct expr * expr) |
a13d4ebf AM |
4007 | { |
4008 | struct ls_expr * mem_ptr; | |
4009 | ||
4010 | if ((mem_ptr = find_rtx_in_ldst (expr->expr))) | |
4011 | { | |
589005ff KH |
4012 | /* We can try to find just the REACHED stores, but is shouldn't |
4013 | matter to set the reaching reg everywhere... some might be | |
a13d4ebf AM |
4014 | dead and should be eliminated later. */ |
4015 | ||
4d3eb89a HPN |
4016 | /* We replace (set mem expr) with (set reg expr) (set mem reg) |
4017 | where reg is the reaching reg used in the load. We checked in | |
4018 | compute_ld_motion_mems that we can replace (set mem expr) with | |
4019 | (set reg expr) in that insn. */ | |
a13d4ebf | 4020 | rtx list = mem_ptr->stores; |
589005ff | 4021 | |
a13d4ebf AM |
4022 | for ( ; list != NULL_RTX; list = XEXP (list, 1)) |
4023 | { | |
4024 | rtx insn = XEXP (list, 0); | |
4025 | rtx pat = PATTERN (insn); | |
4026 | rtx src = SET_SRC (pat); | |
4027 | rtx reg = expr->reaching_reg; | |
038dc49a | 4028 | rtx copy; |
a13d4ebf AM |
4029 | |
4030 | /* If we've already copied it, continue. */ | |
4031 | if (expr->reaching_reg == src) | |
4032 | continue; | |
589005ff | 4033 | |
10d22567 | 4034 | if (dump_file) |
a13d4ebf | 4035 | { |
10d22567 | 4036 | fprintf (dump_file, "PRE: store updated with reaching reg "); |
43c8a043 | 4037 | print_rtl (dump_file, reg); |
10d22567 ZD |
4038 | fprintf (dump_file, ":\n "); |
4039 | print_inline_rtx (dump_file, insn, 8); | |
4040 | fprintf (dump_file, "\n"); | |
a13d4ebf | 4041 | } |
589005ff | 4042 | |
4a81774c | 4043 | copy = gen_move_insn (reg, copy_rtx (SET_SRC (pat))); |
038dc49a | 4044 | emit_insn_before (copy, insn); |
a13d4ebf | 4045 | SET_SRC (pat) = reg; |
6fb5fa3c | 4046 | df_insn_rescan (insn); |
a13d4ebf AM |
4047 | |
4048 | /* un-recognize this pattern since it's probably different now. */ | |
4049 | INSN_CODE (insn) = -1; | |
4050 | gcse_create_count++; | |
4051 | } | |
4052 | } | |
4053 | } | |
4054 | \f | |
df35c271 SB |
4055 | /* Return true if the graph is too expensive to optimize. PASS is the |
4056 | optimization about to be performed. */ | |
47a3dae1 | 4057 | |
df35c271 SB |
4058 | static bool |
4059 | is_too_expensive (const char *pass) | |
4060 | { | |
4061 | /* Trying to perform global optimizations on flow graphs which have | |
4062 | a high connectivity will take a long time and is unlikely to be | |
4063 | particularly useful. | |
aaa4ca30 | 4064 | |
df35c271 SB |
4065 | In normal circumstances a cfg should have about twice as many |
4066 | edges as blocks. But we do not want to punish small functions | |
4067 | which have a couple switch statements. Rather than simply | |
4068 | threshold the number of blocks, uses something with a more | |
4069 | graceful degradation. */ | |
4070 | if (n_edges > 20000 + n_basic_blocks * 4) | |
4071 | { | |
4072 | warning (OPT_Wdisabled_optimization, | |
4073 | "%s: %d basic blocks and %d edges/basic block", | |
4074 | pass, n_basic_blocks, n_edges / n_basic_blocks); | |
a13d4ebf | 4075 | |
df35c271 SB |
4076 | return true; |
4077 | } | |
a13d4ebf | 4078 | |
e45425ec | 4079 | /* If allocating memory for the dataflow bitmaps would take up too much |
df35c271 SB |
4080 | storage it's better just to disable the optimization. */ |
4081 | if ((n_basic_blocks | |
4082 | * SBITMAP_SET_SIZE (max_reg_num ()) | |
4083 | * sizeof (SBITMAP_ELT_TYPE)) > MAX_GCSE_MEMORY) | |
4084 | { | |
4085 | warning (OPT_Wdisabled_optimization, | |
4086 | "%s: %d basic blocks and %d registers", | |
4087 | pass, n_basic_blocks, max_reg_num ()); | |
a13d4ebf | 4088 | |
df35c271 SB |
4089 | return true; |
4090 | } | |
adfcce61 | 4091 | |
df35c271 | 4092 | return false; |
01c43039 | 4093 | } |
df35c271 SB |
4094 | \f |
4095 | /* All the passes implemented in this file. Each pass has its | |
4096 | own gate and execute function, and at the end of the file a | |
4097 | pass definition for passes.c. | |
47a3dae1 | 4098 | |
df35c271 SB |
4099 | We do not construct an accurate cfg in functions which call |
4100 | setjmp, so none of these passes runs if the function calls | |
4101 | setjmp. | |
4102 | FIXME: Should just handle setjmp via REG_SETJMP notes. */ | |
a13d4ebf | 4103 | |
df35c271 SB |
4104 | static bool |
4105 | gate_rtl_pre (void) | |
4106 | { | |
4107 | return optimize > 0 && flag_gcse | |
1f9081d1 XDL |
4108 | && !cfun->calls_setjmp |
4109 | && optimize_function_for_speed_p (cfun) | |
4110 | && dbg_cnt (pre); | |
df35c271 | 4111 | } |
589005ff | 4112 | |
df35c271 SB |
4113 | static unsigned int |
4114 | execute_rtl_pre (void) | |
4115 | { | |
f2b01cfb | 4116 | int changed; |
df35c271 | 4117 | delete_unreachable_blocks (); |
df35c271 | 4118 | df_analyze (); |
f2b01cfb RG |
4119 | changed = one_pre_gcse_pass (); |
4120 | flag_rerun_cse_after_global_opts |= changed; | |
4121 | if (changed) | |
4122 | cleanup_cfg (0); | |
df35c271 SB |
4123 | return 0; |
4124 | } | |
aaa4ca30 | 4125 | |
df35c271 SB |
4126 | static bool |
4127 | gate_rtl_hoist (void) | |
4128 | { | |
4129 | return optimize > 0 && flag_gcse | |
1f9081d1 XDL |
4130 | && !cfun->calls_setjmp |
4131 | /* It does not make sense to run code hoisting unless we are optimizing | |
4132 | for code size -- it rarely makes programs faster, and can make then | |
4133 | bigger if we did PRE (when optimizing for space, we don't run PRE). */ | |
4134 | && optimize_function_for_size_p (cfun) | |
4135 | && dbg_cnt (hoist); | |
df35c271 | 4136 | } |
aaa4ca30 | 4137 | |
df35c271 SB |
4138 | static unsigned int |
4139 | execute_rtl_hoist (void) | |
4140 | { | |
f2b01cfb | 4141 | int changed; |
df35c271 | 4142 | delete_unreachable_blocks (); |
df35c271 | 4143 | df_analyze (); |
f2b01cfb RG |
4144 | changed = one_code_hoisting_pass (); |
4145 | flag_rerun_cse_after_global_opts |= changed; | |
4146 | if (changed) | |
4147 | cleanup_cfg (0); | |
df35c271 SB |
4148 | return 0; |
4149 | } | |
ef330312 | 4150 | |
27a4cd48 DM |
4151 | namespace { |
4152 | ||
4153 | const pass_data pass_data_rtl_pre = | |
ef330312 | 4154 | { |
27a4cd48 DM |
4155 | RTL_PASS, /* type */ |
4156 | "rtl pre", /* name */ | |
4157 | OPTGROUP_NONE, /* optinfo_flags */ | |
4158 | true, /* has_gate */ | |
4159 | true, /* has_execute */ | |
4160 | TV_PRE, /* tv_id */ | |
4161 | PROP_cfglayout, /* properties_required */ | |
4162 | 0, /* properties_provided */ | |
4163 | 0, /* properties_destroyed */ | |
4164 | 0, /* todo_flags_start */ | |
4165 | ( TODO_df_finish | TODO_verify_rtl_sharing | |
4166 | | TODO_verify_flow ), /* todo_flags_finish */ | |
5f39ad47 | 4167 | }; |
ef330312 | 4168 | |
27a4cd48 DM |
4169 | class pass_rtl_pre : public rtl_opt_pass |
4170 | { | |
4171 | public: | |
4172 | pass_rtl_pre(gcc::context *ctxt) | |
4173 | : rtl_opt_pass(pass_data_rtl_pre, ctxt) | |
4174 | {} | |
4175 | ||
4176 | /* opt_pass methods: */ | |
4177 | bool gate () { return gate_rtl_pre (); } | |
4178 | unsigned int execute () { return execute_rtl_pre (); } | |
4179 | ||
4180 | }; // class pass_rtl_pre | |
4181 | ||
4182 | } // anon namespace | |
4183 | ||
4184 | rtl_opt_pass * | |
4185 | make_pass_rtl_pre (gcc::context *ctxt) | |
4186 | { | |
4187 | return new pass_rtl_pre (ctxt); | |
4188 | } | |
4189 | ||
4190 | namespace { | |
4191 | ||
4192 | const pass_data pass_data_rtl_hoist = | |
ef330312 | 4193 | { |
27a4cd48 DM |
4194 | RTL_PASS, /* type */ |
4195 | "hoist", /* name */ | |
4196 | OPTGROUP_NONE, /* optinfo_flags */ | |
4197 | true, /* has_gate */ | |
4198 | true, /* has_execute */ | |
4199 | TV_HOIST, /* tv_id */ | |
4200 | PROP_cfglayout, /* properties_required */ | |
4201 | 0, /* properties_provided */ | |
4202 | 0, /* properties_destroyed */ | |
4203 | 0, /* todo_flags_start */ | |
4204 | ( TODO_df_finish | TODO_verify_rtl_sharing | |
4205 | | TODO_verify_flow ), /* todo_flags_finish */ | |
ef330312 PB |
4206 | }; |
4207 | ||
27a4cd48 DM |
4208 | class pass_rtl_hoist : public rtl_opt_pass |
4209 | { | |
4210 | public: | |
4211 | pass_rtl_hoist(gcc::context *ctxt) | |
4212 | : rtl_opt_pass(pass_data_rtl_hoist, ctxt) | |
4213 | {} | |
4214 | ||
4215 | /* opt_pass methods: */ | |
4216 | bool gate () { return gate_rtl_hoist (); } | |
4217 | unsigned int execute () { return execute_rtl_hoist (); } | |
4218 | ||
4219 | }; // class pass_rtl_hoist | |
4220 | ||
4221 | } // anon namespace | |
4222 | ||
4223 | rtl_opt_pass * | |
4224 | make_pass_rtl_hoist (gcc::context *ctxt) | |
4225 | { | |
4226 | return new pass_rtl_hoist (ctxt); | |
4227 | } | |
4228 | ||
e2500fed | 4229 | #include "gt-gcse.h" |