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f4e584dc | 1 | /* Global common subexpression elimination/Partial redundancy elimination |
7506f491 | 2 | and global constant/copy propagation for GNU compiler. |
a0134312 | 3 | Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003 |
8e42ace1 | 4 | Free Software Foundation, Inc. |
7506f491 | 5 | |
1322177d | 6 | This file is part of GCC. |
7506f491 | 7 | |
1322177d LB |
8 | GCC is free software; you can redistribute it and/or modify it under |
9 | the terms of the GNU General Public License as published by the Free | |
10 | Software Foundation; either version 2, or (at your option) any later | |
11 | version. | |
7506f491 | 12 | |
1322177d LB |
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
7506f491 DE |
17 | |
18 | You should have received a copy of the GNU General Public License | |
1322177d LB |
19 | along with GCC; see the file COPYING. If not, write to the Free |
20 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
21 | 02111-1307, USA. */ | |
7506f491 DE |
22 | |
23 | /* TODO | |
24 | - reordering of memory allocation and freeing to be more space efficient | |
25 | - do rough calc of how many regs are needed in each block, and a rough | |
26 | calc of how many regs are available in each class and use that to | |
27 | throttle back the code in cases where RTX_COST is minimal. | |
f4e584dc JL |
28 | - a store to the same address as a load does not kill the load if the |
29 | source of the store is also the destination of the load. Handling this | |
30 | allows more load motion, particularly out of loops. | |
7506f491 DE |
31 | - ability to realloc sbitmap vectors would allow one initial computation |
32 | of reg_set_in_block with only subsequent additions, rather than | |
33 | recomputing it for each pass | |
34 | ||
7506f491 DE |
35 | */ |
36 | ||
37 | /* References searched while implementing this. | |
7506f491 DE |
38 | |
39 | Compilers Principles, Techniques and Tools | |
40 | Aho, Sethi, Ullman | |
41 | Addison-Wesley, 1988 | |
42 | ||
43 | Global Optimization by Suppression of Partial Redundancies | |
44 | E. Morel, C. Renvoise | |
45 | communications of the acm, Vol. 22, Num. 2, Feb. 1979 | |
46 | ||
47 | A Portable Machine-Independent Global Optimizer - Design and Measurements | |
48 | Frederick Chow | |
49 | Stanford Ph.D. thesis, Dec. 1983 | |
50 | ||
7506f491 DE |
51 | A Fast Algorithm for Code Movement Optimization |
52 | D.M. Dhamdhere | |
53 | SIGPLAN Notices, Vol. 23, Num. 10, Oct. 1988 | |
54 | ||
55 | A Solution to a Problem with Morel and Renvoise's | |
56 | Global Optimization by Suppression of Partial Redundancies | |
57 | K-H Drechsler, M.P. Stadel | |
58 | ACM TOPLAS, Vol. 10, Num. 4, Oct. 1988 | |
59 | ||
60 | Practical Adaptation of the Global Optimization | |
61 | Algorithm of Morel and Renvoise | |
62 | D.M. Dhamdhere | |
63 | ACM TOPLAS, Vol. 13, Num. 2. Apr. 1991 | |
64 | ||
65 | Efficiently Computing Static Single Assignment Form and the Control | |
66 | Dependence Graph | |
67 | R. Cytron, J. Ferrante, B.K. Rosen, M.N. Wegman, and F.K. Zadeck | |
68 | ACM TOPLAS, Vol. 13, Num. 4, Oct. 1991 | |
69 | ||
7506f491 DE |
70 | Lazy Code Motion |
71 | J. Knoop, O. Ruthing, B. Steffen | |
72 | ACM SIGPLAN Notices Vol. 27, Num. 7, Jul. 1992, '92 Conference on PLDI | |
73 | ||
74 | What's In a Region? Or Computing Control Dependence Regions in Near-Linear | |
75 | Time for Reducible Flow Control | |
76 | Thomas Ball | |
77 | ACM Letters on Programming Languages and Systems, | |
78 | Vol. 2, Num. 1-4, Mar-Dec 1993 | |
79 | ||
80 | An Efficient Representation for Sparse Sets | |
81 | Preston Briggs, Linda Torczon | |
82 | ACM Letters on Programming Languages and Systems, | |
83 | Vol. 2, Num. 1-4, Mar-Dec 1993 | |
84 | ||
85 | A Variation of Knoop, Ruthing, and Steffen's Lazy Code Motion | |
86 | K-H Drechsler, M.P. Stadel | |
87 | ACM SIGPLAN Notices, Vol. 28, Num. 5, May 1993 | |
88 | ||
89 | Partial Dead Code Elimination | |
90 | J. Knoop, O. Ruthing, B. Steffen | |
91 | ACM SIGPLAN Notices, Vol. 29, Num. 6, Jun. 1994 | |
92 | ||
93 | Effective Partial Redundancy Elimination | |
94 | P. Briggs, K.D. Cooper | |
95 | ACM SIGPLAN Notices, Vol. 29, Num. 6, Jun. 1994 | |
96 | ||
97 | The Program Structure Tree: Computing Control Regions in Linear Time | |
98 | R. Johnson, D. Pearson, K. Pingali | |
99 | ACM SIGPLAN Notices, Vol. 29, Num. 6, Jun. 1994 | |
100 | ||
101 | Optimal Code Motion: Theory and Practice | |
102 | J. Knoop, O. Ruthing, B. Steffen | |
103 | ACM TOPLAS, Vol. 16, Num. 4, Jul. 1994 | |
104 | ||
105 | The power of assignment motion | |
106 | J. Knoop, O. Ruthing, B. Steffen | |
107 | ACM SIGPLAN Notices Vol. 30, Num. 6, Jun. 1995, '95 Conference on PLDI | |
108 | ||
109 | Global code motion / global value numbering | |
110 | C. Click | |
111 | ACM SIGPLAN Notices Vol. 30, Num. 6, Jun. 1995, '95 Conference on PLDI | |
112 | ||
113 | Value Driven Redundancy Elimination | |
114 | L.T. Simpson | |
115 | Rice University Ph.D. thesis, Apr. 1996 | |
116 | ||
117 | Value Numbering | |
118 | L.T. Simpson | |
119 | Massively Scalar Compiler Project, Rice University, Sep. 1996 | |
120 | ||
121 | High Performance Compilers for Parallel Computing | |
122 | Michael Wolfe | |
123 | Addison-Wesley, 1996 | |
124 | ||
f4e584dc JL |
125 | Advanced Compiler Design and Implementation |
126 | Steven Muchnick | |
127 | Morgan Kaufmann, 1997 | |
128 | ||
a42cd965 AM |
129 | Building an Optimizing Compiler |
130 | Robert Morgan | |
131 | Digital Press, 1998 | |
132 | ||
f4e584dc JL |
133 | People wishing to speed up the code here should read: |
134 | Elimination Algorithms for Data Flow Analysis | |
135 | B.G. Ryder, M.C. Paull | |
136 | ACM Computing Surveys, Vol. 18, Num. 3, Sep. 1986 | |
137 | ||
138 | How to Analyze Large Programs Efficiently and Informatively | |
139 | D.M. Dhamdhere, B.K. Rosen, F.K. Zadeck | |
140 | ACM SIGPLAN Notices Vol. 27, Num. 7, Jul. 1992, '92 Conference on PLDI | |
141 | ||
7506f491 DE |
142 | People wishing to do something different can find various possibilities |
143 | in the above papers and elsewhere. | |
144 | */ | |
145 | ||
146 | #include "config.h" | |
50b2596f | 147 | #include "system.h" |
4977bab6 ZW |
148 | #include "coretypes.h" |
149 | #include "tm.h" | |
01198c2f | 150 | #include "toplev.h" |
7506f491 DE |
151 | |
152 | #include "rtl.h" | |
6baf1cc8 | 153 | #include "tm_p.h" |
7506f491 DE |
154 | #include "regs.h" |
155 | #include "hard-reg-set.h" | |
156 | #include "flags.h" | |
157 | #include "real.h" | |
158 | #include "insn-config.h" | |
159 | #include "recog.h" | |
160 | #include "basic-block.h" | |
50b2596f | 161 | #include "output.h" |
49ad7cfa | 162 | #include "function.h" |
589005ff | 163 | #include "expr.h" |
e7d482b9 | 164 | #include "except.h" |
fb0c0a12 | 165 | #include "ggc.h" |
f1fa37ff | 166 | #include "params.h" |
ae860ff7 | 167 | #include "cselib.h" |
aaa4ca30 | 168 | |
7506f491 | 169 | #include "obstack.h" |
4fa31c2a | 170 | |
7506f491 DE |
171 | /* Propagate flow information through back edges and thus enable PRE's |
172 | moving loop invariant calculations out of loops. | |
173 | ||
174 | Originally this tended to create worse overall code, but several | |
175 | improvements during the development of PRE seem to have made following | |
176 | back edges generally a win. | |
177 | ||
178 | Note much of the loop invariant code motion done here would normally | |
179 | be done by loop.c, which has more heuristics for when to move invariants | |
180 | out of loops. At some point we might need to move some of those | |
181 | heuristics into gcse.c. */ | |
7506f491 | 182 | |
f4e584dc JL |
183 | /* We support GCSE via Partial Redundancy Elimination. PRE optimizations |
184 | are a superset of those done by GCSE. | |
7506f491 | 185 | |
f4e584dc | 186 | We perform the following steps: |
7506f491 DE |
187 | |
188 | 1) Compute basic block information. | |
189 | ||
190 | 2) Compute table of places where registers are set. | |
191 | ||
192 | 3) Perform copy/constant propagation. | |
193 | ||
194 | 4) Perform global cse. | |
195 | ||
e78d9500 | 196 | 5) Perform another pass of copy/constant propagation. |
7506f491 DE |
197 | |
198 | Two passes of copy/constant propagation are done because the first one | |
199 | enables more GCSE and the second one helps to clean up the copies that | |
200 | GCSE creates. This is needed more for PRE than for Classic because Classic | |
201 | GCSE will try to use an existing register containing the common | |
202 | subexpression rather than create a new one. This is harder to do for PRE | |
203 | because of the code motion (which Classic GCSE doesn't do). | |
204 | ||
205 | Expressions we are interested in GCSE-ing are of the form | |
206 | (set (pseudo-reg) (expression)). | |
207 | Function want_to_gcse_p says what these are. | |
208 | ||
209 | PRE handles moving invariant expressions out of loops (by treating them as | |
f4e584dc | 210 | partially redundant). |
7506f491 DE |
211 | |
212 | Eventually it would be nice to replace cse.c/gcse.c with SSA (static single | |
213 | assignment) based GVN (global value numbering). L. T. Simpson's paper | |
214 | (Rice University) on value numbering is a useful reference for this. | |
215 | ||
216 | ********************** | |
217 | ||
218 | We used to support multiple passes but there are diminishing returns in | |
219 | doing so. The first pass usually makes 90% of the changes that are doable. | |
220 | A second pass can make a few more changes made possible by the first pass. | |
221 | Experiments show any further passes don't make enough changes to justify | |
222 | the expense. | |
223 | ||
224 | A study of spec92 using an unlimited number of passes: | |
225 | [1 pass] = 1208 substitutions, [2] = 577, [3] = 202, [4] = 192, [5] = 83, | |
226 | [6] = 34, [7] = 17, [8] = 9, [9] = 4, [10] = 4, [11] = 2, | |
227 | [12] = 2, [13] = 1, [15] = 1, [16] = 2, [41] = 1 | |
228 | ||
229 | It was found doing copy propagation between each pass enables further | |
230 | substitutions. | |
231 | ||
232 | PRE is quite expensive in complicated functions because the DFA can take | |
740f35a0 | 233 | awhile to converge. Hence we only perform one pass. The parameter max-gcse-passes can |
7506f491 DE |
234 | be modified if one wants to experiment. |
235 | ||
236 | ********************** | |
237 | ||
238 | The steps for PRE are: | |
239 | ||
240 | 1) Build the hash table of expressions we wish to GCSE (expr_hash_table). | |
241 | ||
242 | 2) Perform the data flow analysis for PRE. | |
243 | ||
244 | 3) Delete the redundant instructions | |
245 | ||
246 | 4) Insert the required copies [if any] that make the partially | |
247 | redundant instructions fully redundant. | |
248 | ||
249 | 5) For other reaching expressions, insert an instruction to copy the value | |
250 | to a newly created pseudo that will reach the redundant instruction. | |
251 | ||
252 | The deletion is done first so that when we do insertions we | |
253 | know which pseudo reg to use. | |
254 | ||
255 | Various papers have argued that PRE DFA is expensive (O(n^2)) and others | |
256 | argue it is not. The number of iterations for the algorithm to converge | |
257 | is typically 2-4 so I don't view it as that expensive (relatively speaking). | |
258 | ||
f4e584dc | 259 | PRE GCSE depends heavily on the second CSE pass to clean up the copies |
7506f491 DE |
260 | we create. To make an expression reach the place where it's redundant, |
261 | the result of the expression is copied to a new register, and the redundant | |
262 | expression is deleted by replacing it with this new register. Classic GCSE | |
263 | doesn't have this problem as much as it computes the reaching defs of | |
264 | each register in each block and thus can try to use an existing register. | |
265 | ||
266 | ********************** | |
267 | ||
7506f491 DE |
268 | A fair bit of simplicity is created by creating small functions for simple |
269 | tasks, even when the function is only called in one place. This may | |
270 | measurably slow things down [or may not] by creating more function call | |
271 | overhead than is necessary. The source is laid out so that it's trivial | |
272 | to make the affected functions inline so that one can measure what speed | |
273 | up, if any, can be achieved, and maybe later when things settle things can | |
274 | be rearranged. | |
275 | ||
276 | Help stamp out big monolithic functions! */ | |
277 | \f | |
278 | /* GCSE global vars. */ | |
279 | ||
280 | /* -dG dump file. */ | |
281 | static FILE *gcse_file; | |
282 | ||
f4e584dc JL |
283 | /* Note whether or not we should run jump optimization after gcse. We |
284 | want to do this for two cases. | |
285 | ||
286 | * If we changed any jumps via cprop. | |
287 | ||
288 | * If we added any labels via edge splitting. */ | |
289 | ||
290 | static int run_jump_opt_after_gcse; | |
291 | ||
7506f491 DE |
292 | /* Bitmaps are normally not included in debugging dumps. |
293 | However it's useful to be able to print them from GDB. | |
294 | We could create special functions for this, but it's simpler to | |
295 | just allow passing stderr to the dump_foo fns. Since stderr can | |
296 | be a macro, we store a copy here. */ | |
297 | static FILE *debug_stderr; | |
298 | ||
299 | /* An obstack for our working variables. */ | |
300 | static struct obstack gcse_obstack; | |
301 | ||
c4c81601 | 302 | struct reg_use {rtx reg_rtx; }; |
abd535b6 | 303 | |
7506f491 DE |
304 | /* Hash table of expressions. */ |
305 | ||
306 | struct expr | |
307 | { | |
308 | /* The expression (SET_SRC for expressions, PATTERN for assignments). */ | |
309 | rtx expr; | |
310 | /* Index in the available expression bitmaps. */ | |
311 | int bitmap_index; | |
312 | /* Next entry with the same hash. */ | |
313 | struct expr *next_same_hash; | |
314 | /* List of anticipatable occurrences in basic blocks in the function. | |
315 | An "anticipatable occurrence" is one that is the first occurrence in the | |
f4e584dc JL |
316 | basic block, the operands are not modified in the basic block prior |
317 | to the occurrence and the output is not used between the start of | |
318 | the block and the occurrence. */ | |
7506f491 DE |
319 | struct occr *antic_occr; |
320 | /* List of available occurrence in basic blocks in the function. | |
321 | An "available occurrence" is one that is the last occurrence in the | |
322 | basic block and the operands are not modified by following statements in | |
323 | the basic block [including this insn]. */ | |
324 | struct occr *avail_occr; | |
325 | /* Non-null if the computation is PRE redundant. | |
326 | The value is the newly created pseudo-reg to record a copy of the | |
327 | expression in all the places that reach the redundant copy. */ | |
328 | rtx reaching_reg; | |
329 | }; | |
330 | ||
331 | /* Occurrence of an expression. | |
332 | There is one per basic block. If a pattern appears more than once the | |
333 | last appearance is used [or first for anticipatable expressions]. */ | |
334 | ||
335 | struct occr | |
336 | { | |
337 | /* Next occurrence of this expression. */ | |
338 | struct occr *next; | |
339 | /* The insn that computes the expression. */ | |
340 | rtx insn; | |
cc2902df | 341 | /* Nonzero if this [anticipatable] occurrence has been deleted. */ |
7506f491 | 342 | char deleted_p; |
cc2902df | 343 | /* Nonzero if this [available] occurrence has been copied to |
7506f491 DE |
344 | reaching_reg. */ |
345 | /* ??? This is mutually exclusive with deleted_p, so they could share | |
346 | the same byte. */ | |
347 | char copied_p; | |
348 | }; | |
349 | ||
350 | /* Expression and copy propagation hash tables. | |
351 | Each hash table is an array of buckets. | |
352 | ??? It is known that if it were an array of entries, structure elements | |
353 | `next_same_hash' and `bitmap_index' wouldn't be necessary. However, it is | |
354 | not clear whether in the final analysis a sufficient amount of memory would | |
355 | be saved as the size of the available expression bitmaps would be larger | |
356 | [one could build a mapping table without holes afterwards though]. | |
c4c81601 | 357 | Someday I'll perform the computation and figure it out. */ |
7506f491 | 358 | |
02280659 ZD |
359 | struct hash_table |
360 | { | |
361 | /* The table itself. | |
362 | This is an array of `expr_hash_table_size' elements. */ | |
363 | struct expr **table; | |
364 | ||
365 | /* Size of the hash table, in elements. */ | |
366 | unsigned int size; | |
2e653e39 | 367 | |
02280659 ZD |
368 | /* Number of hash table elements. */ |
369 | unsigned int n_elems; | |
7506f491 | 370 | |
02280659 ZD |
371 | /* Whether the table is expression of copy propagation one. */ |
372 | int set_p; | |
373 | }; | |
c4c81601 | 374 | |
02280659 ZD |
375 | /* Expression hash table. */ |
376 | static struct hash_table expr_hash_table; | |
377 | ||
378 | /* Copy propagation hash table. */ | |
379 | static struct hash_table set_hash_table; | |
7506f491 DE |
380 | |
381 | /* Mapping of uids to cuids. | |
382 | Only real insns get cuids. */ | |
383 | static int *uid_cuid; | |
384 | ||
385 | /* Highest UID in UID_CUID. */ | |
386 | static int max_uid; | |
387 | ||
388 | /* Get the cuid of an insn. */ | |
b86db3eb BS |
389 | #ifdef ENABLE_CHECKING |
390 | #define INSN_CUID(INSN) (INSN_UID (INSN) > max_uid ? (abort (), 0) : uid_cuid[INSN_UID (INSN)]) | |
391 | #else | |
7506f491 | 392 | #define INSN_CUID(INSN) (uid_cuid[INSN_UID (INSN)]) |
b86db3eb | 393 | #endif |
7506f491 DE |
394 | |
395 | /* Number of cuids. */ | |
396 | static int max_cuid; | |
397 | ||
398 | /* Mapping of cuids to insns. */ | |
399 | static rtx *cuid_insn; | |
400 | ||
401 | /* Get insn from cuid. */ | |
402 | #define CUID_INSN(CUID) (cuid_insn[CUID]) | |
403 | ||
404 | /* Maximum register number in function prior to doing gcse + 1. | |
405 | Registers created during this pass have regno >= max_gcse_regno. | |
406 | This is named with "gcse" to not collide with global of same name. */ | |
770ae6cc | 407 | static unsigned int max_gcse_regno; |
7506f491 | 408 | |
7506f491 | 409 | /* Table of registers that are modified. |
c4c81601 | 410 | |
7506f491 DE |
411 | For each register, each element is a list of places where the pseudo-reg |
412 | is set. | |
413 | ||
414 | For simplicity, GCSE is done on sets of pseudo-regs only. PRE GCSE only | |
415 | requires knowledge of which blocks kill which regs [and thus could use | |
f4e584dc | 416 | a bitmap instead of the lists `reg_set_table' uses]. |
7506f491 | 417 | |
c4c81601 RK |
418 | `reg_set_table' and could be turned into an array of bitmaps (num-bbs x |
419 | num-regs) [however perhaps it may be useful to keep the data as is]. One | |
420 | advantage of recording things this way is that `reg_set_table' is fairly | |
421 | sparse with respect to pseudo regs but for hard regs could be fairly dense | |
422 | [relatively speaking]. And recording sets of pseudo-regs in lists speeds | |
7506f491 DE |
423 | up functions like compute_transp since in the case of pseudo-regs we only |
424 | need to iterate over the number of times a pseudo-reg is set, not over the | |
425 | number of basic blocks [clearly there is a bit of a slow down in the cases | |
426 | where a pseudo is set more than once in a block, however it is believed | |
427 | that the net effect is to speed things up]. This isn't done for hard-regs | |
428 | because recording call-clobbered hard-regs in `reg_set_table' at each | |
c4c81601 RK |
429 | function call can consume a fair bit of memory, and iterating over |
430 | hard-regs stored this way in compute_transp will be more expensive. */ | |
7506f491 | 431 | |
c4c81601 RK |
432 | typedef struct reg_set |
433 | { | |
7506f491 DE |
434 | /* The next setting of this register. */ |
435 | struct reg_set *next; | |
436 | /* The insn where it was set. */ | |
437 | rtx insn; | |
438 | } reg_set; | |
c4c81601 | 439 | |
7506f491 | 440 | static reg_set **reg_set_table; |
c4c81601 | 441 | |
7506f491 DE |
442 | /* Size of `reg_set_table'. |
443 | The table starts out at max_gcse_regno + slop, and is enlarged as | |
444 | necessary. */ | |
445 | static int reg_set_table_size; | |
c4c81601 | 446 | |
7506f491 DE |
447 | /* Amount to grow `reg_set_table' by when it's full. */ |
448 | #define REG_SET_TABLE_SLOP 100 | |
449 | ||
a13d4ebf | 450 | /* This is a list of expressions which are MEMs and will be used by load |
589005ff | 451 | or store motion. |
a13d4ebf AM |
452 | Load motion tracks MEMs which aren't killed by |
453 | anything except itself. (ie, loads and stores to a single location). | |
589005ff | 454 | We can then allow movement of these MEM refs with a little special |
a13d4ebf AM |
455 | allowance. (all stores copy the same value to the reaching reg used |
456 | for the loads). This means all values used to store into memory must have | |
589005ff | 457 | no side effects so we can re-issue the setter value. |
a13d4ebf AM |
458 | Store Motion uses this structure as an expression table to track stores |
459 | which look interesting, and might be moveable towards the exit block. */ | |
460 | ||
461 | struct ls_expr | |
462 | { | |
463 | struct expr * expr; /* Gcse expression reference for LM. */ | |
464 | rtx pattern; /* Pattern of this mem. */ | |
47a3dae1 | 465 | rtx pattern_regs; /* List of registers mentioned by the mem. */ |
aaa4ca30 AJ |
466 | rtx loads; /* INSN list of loads seen. */ |
467 | rtx stores; /* INSN list of stores seen. */ | |
a13d4ebf AM |
468 | struct ls_expr * next; /* Next in the list. */ |
469 | int invalid; /* Invalid for some reason. */ | |
470 | int index; /* If it maps to a bitmap index. */ | |
471 | int hash_index; /* Index when in a hash table. */ | |
472 | rtx reaching_reg; /* Register to use when re-writing. */ | |
473 | }; | |
474 | ||
fbef91d8 RS |
475 | /* Array of implicit set patterns indexed by basic block index. */ |
476 | static rtx *implicit_sets; | |
477 | ||
a13d4ebf AM |
478 | /* Head of the list of load/store memory refs. */ |
479 | static struct ls_expr * pre_ldst_mems = NULL; | |
480 | ||
7506f491 DE |
481 | /* Bitmap containing one bit for each register in the program. |
482 | Used when performing GCSE to track which registers have been set since | |
483 | the start of the basic block. */ | |
73991d6a | 484 | static regset reg_set_bitmap; |
7506f491 DE |
485 | |
486 | /* For each block, a bitmap of registers set in the block. | |
487 | This is used by expr_killed_p and compute_transp. | |
488 | It is computed during hash table computation and not by compute_sets | |
489 | as it includes registers added since the last pass (or between cprop and | |
490 | gcse) and it's currently not easy to realloc sbitmap vectors. */ | |
491 | static sbitmap *reg_set_in_block; | |
492 | ||
a13d4ebf AM |
493 | /* Array, indexed by basic block number for a list of insns which modify |
494 | memory within that block. */ | |
495 | static rtx * modify_mem_list; | |
73991d6a | 496 | bitmap modify_mem_list_set; |
a13d4ebf AM |
497 | |
498 | /* This array parallels modify_mem_list, but is kept canonicalized. */ | |
499 | static rtx * canon_modify_mem_list; | |
73991d6a | 500 | bitmap canon_modify_mem_list_set; |
7506f491 DE |
501 | /* Various variables for statistics gathering. */ |
502 | ||
503 | /* Memory used in a pass. | |
504 | This isn't intended to be absolutely precise. Its intent is only | |
505 | to keep an eye on memory usage. */ | |
506 | static int bytes_used; | |
c4c81601 | 507 | |
7506f491 DE |
508 | /* GCSE substitutions made. */ |
509 | static int gcse_subst_count; | |
510 | /* Number of copy instructions created. */ | |
511 | static int gcse_create_count; | |
512 | /* Number of constants propagated. */ | |
513 | static int const_prop_count; | |
514 | /* Number of copys propagated. */ | |
515 | static int copy_prop_count; | |
7506f491 DE |
516 | \f |
517 | /* These variables are used by classic GCSE. | |
518 | Normally they'd be defined a bit later, but `rd_gen' needs to | |
519 | be declared sooner. */ | |
520 | ||
7506f491 DE |
521 | /* Each block has a bitmap of each type. |
522 | The length of each blocks bitmap is: | |
523 | ||
524 | max_cuid - for reaching definitions | |
525 | n_exprs - for available expressions | |
526 | ||
527 | Thus we view the bitmaps as 2 dimensional arrays. i.e. | |
528 | rd_kill[block_num][cuid_num] | |
c4c81601 | 529 | ae_kill[block_num][expr_num] */ |
7506f491 DE |
530 | |
531 | /* For reaching defs */ | |
532 | static sbitmap *rd_kill, *rd_gen, *reaching_defs, *rd_out; | |
533 | ||
534 | /* for available exprs */ | |
535 | static sbitmap *ae_kill, *ae_gen, *ae_in, *ae_out; | |
b5ce41ff | 536 | |
0511851c MM |
537 | /* Objects of this type are passed around by the null-pointer check |
538 | removal routines. */ | |
c4c81601 RK |
539 | struct null_pointer_info |
540 | { | |
0511851c | 541 | /* The basic block being processed. */ |
e0082a72 | 542 | basic_block current_block; |
0511851c | 543 | /* The first register to be handled in this pass. */ |
770ae6cc | 544 | unsigned int min_reg; |
0511851c | 545 | /* One greater than the last register to be handled in this pass. */ |
770ae6cc | 546 | unsigned int max_reg; |
0511851c MM |
547 | sbitmap *nonnull_local; |
548 | sbitmap *nonnull_killed; | |
549 | }; | |
7506f491 | 550 | \f |
1d088dee | 551 | static void compute_can_copy (void); |
703ad42b KG |
552 | static void *gmalloc (unsigned int); |
553 | static void *grealloc (void *, unsigned int); | |
554 | static void *gcse_alloc (unsigned long); | |
1d088dee AJ |
555 | static void alloc_gcse_mem (rtx); |
556 | static void free_gcse_mem (void); | |
557 | static void alloc_reg_set_mem (int); | |
558 | static void free_reg_set_mem (void); | |
559 | static int get_bitmap_width (int, int, int); | |
560 | static void record_one_set (int, rtx); | |
561 | static void record_set_info (rtx, rtx, void *); | |
562 | static void compute_sets (rtx); | |
563 | static void hash_scan_insn (rtx, struct hash_table *, int); | |
564 | static void hash_scan_set (rtx, rtx, struct hash_table *); | |
565 | static void hash_scan_clobber (rtx, rtx, struct hash_table *); | |
566 | static void hash_scan_call (rtx, rtx, struct hash_table *); | |
567 | static int want_to_gcse_p (rtx); | |
568 | static bool gcse_constant_p (rtx); | |
569 | static int oprs_unchanged_p (rtx, rtx, int); | |
570 | static int oprs_anticipatable_p (rtx, rtx); | |
571 | static int oprs_available_p (rtx, rtx); | |
572 | static void insert_expr_in_table (rtx, enum machine_mode, rtx, int, int, | |
573 | struct hash_table *); | |
574 | static void insert_set_in_table (rtx, rtx, struct hash_table *); | |
575 | static unsigned int hash_expr (rtx, enum machine_mode, int *, int); | |
576 | static unsigned int hash_expr_1 (rtx, enum machine_mode, int *); | |
577 | static unsigned int hash_string_1 (const char *); | |
578 | static unsigned int hash_set (int, int); | |
579 | static int expr_equiv_p (rtx, rtx); | |
580 | static void record_last_reg_set_info (rtx, int); | |
581 | static void record_last_mem_set_info (rtx); | |
582 | static void record_last_set_info (rtx, rtx, void *); | |
583 | static void compute_hash_table (struct hash_table *); | |
584 | static void alloc_hash_table (int, struct hash_table *, int); | |
585 | static void free_hash_table (struct hash_table *); | |
586 | static void compute_hash_table_work (struct hash_table *); | |
587 | static void dump_hash_table (FILE *, const char *, struct hash_table *); | |
588 | static struct expr *lookup_expr (rtx, struct hash_table *); | |
589 | static struct expr *lookup_set (unsigned int, struct hash_table *); | |
590 | static struct expr *next_set (unsigned int, struct expr *); | |
591 | static void reset_opr_set_tables (void); | |
592 | static int oprs_not_set_p (rtx, rtx); | |
593 | static void mark_call (rtx); | |
594 | static void mark_set (rtx, rtx); | |
595 | static void mark_clobber (rtx, rtx); | |
596 | static void mark_oprs_set (rtx); | |
597 | static void alloc_cprop_mem (int, int); | |
598 | static void free_cprop_mem (void); | |
599 | static void compute_transp (rtx, int, sbitmap *, int); | |
600 | static void compute_transpout (void); | |
601 | static void compute_local_properties (sbitmap *, sbitmap *, sbitmap *, | |
602 | struct hash_table *); | |
603 | static void compute_cprop_data (void); | |
604 | static void find_used_regs (rtx *, void *); | |
605 | static int try_replace_reg (rtx, rtx, rtx); | |
606 | static struct expr *find_avail_set (int, rtx); | |
607 | static int cprop_jump (basic_block, rtx, rtx, rtx, rtx); | |
608 | static void mems_conflict_for_gcse_p (rtx, rtx, void *); | |
609 | static int load_killed_in_block_p (basic_block, int, rtx, int); | |
610 | static void canon_list_insert (rtx, rtx, void *); | |
611 | static int cprop_insn (rtx, int); | |
612 | static int cprop (int); | |
613 | static void find_implicit_sets (void); | |
614 | static int one_cprop_pass (int, int, int); | |
615 | static bool constprop_register (rtx, rtx, rtx, int); | |
616 | static struct expr *find_bypass_set (int, int); | |
617 | static bool reg_killed_on_edge (rtx, edge); | |
618 | static int bypass_block (basic_block, rtx, rtx); | |
619 | static int bypass_conditional_jumps (void); | |
620 | static void alloc_pre_mem (int, int); | |
621 | static void free_pre_mem (void); | |
622 | static void compute_pre_data (void); | |
623 | static int pre_expr_reaches_here_p (basic_block, struct expr *, | |
624 | basic_block); | |
625 | static void insert_insn_end_bb (struct expr *, basic_block, int); | |
626 | static void pre_insert_copy_insn (struct expr *, rtx); | |
627 | static void pre_insert_copies (void); | |
628 | static int pre_delete (void); | |
629 | static int pre_gcse (void); | |
630 | static int one_pre_gcse_pass (int); | |
631 | static void add_label_notes (rtx, rtx); | |
632 | static void alloc_code_hoist_mem (int, int); | |
633 | static void free_code_hoist_mem (void); | |
634 | static void compute_code_hoist_vbeinout (void); | |
635 | static void compute_code_hoist_data (void); | |
636 | static int hoist_expr_reaches_here_p (basic_block, int, basic_block, char *); | |
637 | static void hoist_code (void); | |
638 | static int one_code_hoisting_pass (void); | |
639 | static void alloc_rd_mem (int, int); | |
640 | static void free_rd_mem (void); | |
641 | static void handle_rd_kill_set (rtx, int, basic_block); | |
642 | static void compute_kill_rd (void); | |
643 | static void compute_rd (void); | |
644 | static void alloc_avail_expr_mem (int, int); | |
645 | static void free_avail_expr_mem (void); | |
646 | static void compute_ae_gen (struct hash_table *); | |
647 | static int expr_killed_p (rtx, basic_block); | |
648 | static void compute_ae_kill (sbitmap *, sbitmap *, struct hash_table *); | |
649 | static int expr_reaches_here_p (struct occr *, struct expr *, basic_block, | |
650 | int); | |
651 | static rtx computing_insn (struct expr *, rtx); | |
652 | static int def_reaches_here_p (rtx, rtx); | |
653 | static int can_disregard_other_sets (struct reg_set **, rtx, int); | |
654 | static int handle_avail_expr (rtx, struct expr *); | |
655 | static int classic_gcse (void); | |
656 | static int one_classic_gcse_pass (int); | |
657 | static void invalidate_nonnull_info (rtx, rtx, void *); | |
658 | static int delete_null_pointer_checks_1 (unsigned int *, sbitmap *, sbitmap *, | |
659 | struct null_pointer_info *); | |
660 | static rtx process_insert_insn (struct expr *); | |
661 | static int pre_edge_insert (struct edge_list *, struct expr **); | |
662 | static int expr_reaches_here_p_work (struct occr *, struct expr *, | |
663 | basic_block, int, char *); | |
664 | static int pre_expr_reaches_here_p_work (basic_block, struct expr *, | |
665 | basic_block, char *); | |
666 | static struct ls_expr * ldst_entry (rtx); | |
667 | static void free_ldst_entry (struct ls_expr *); | |
668 | static void free_ldst_mems (void); | |
669 | static void print_ldst_list (FILE *); | |
670 | static struct ls_expr * find_rtx_in_ldst (rtx); | |
671 | static int enumerate_ldsts (void); | |
672 | static inline struct ls_expr * first_ls_expr (void); | |
673 | static inline struct ls_expr * next_ls_expr (struct ls_expr *); | |
674 | static int simple_mem (rtx); | |
675 | static void invalidate_any_buried_refs (rtx); | |
676 | static void compute_ld_motion_mems (void); | |
677 | static void trim_ld_motion_mems (void); | |
678 | static void update_ld_motion_stores (struct expr *); | |
679 | static void reg_set_info (rtx, rtx, void *); | |
680 | static bool store_ops_ok (rtx, int *); | |
681 | static rtx extract_mentioned_regs (rtx); | |
682 | static rtx extract_mentioned_regs_helper (rtx, rtx); | |
683 | static void find_moveable_store (rtx, int *, int *); | |
684 | static int compute_store_table (void); | |
3b14e3af ZD |
685 | static bool load_kills_store (rtx, rtx, int); |
686 | static bool find_loads (rtx, rtx, int); | |
687 | static bool store_killed_in_insn (rtx, rtx, rtx, int); | |
1d088dee AJ |
688 | static bool store_killed_after (rtx, rtx, rtx, basic_block, int *, rtx *); |
689 | static bool store_killed_before (rtx, rtx, rtx, basic_block, int *); | |
690 | static void build_store_vectors (void); | |
691 | static void insert_insn_start_bb (rtx, basic_block); | |
692 | static int insert_store (struct ls_expr *, edge); | |
693 | static void replace_store_insn (rtx, rtx, basic_block); | |
694 | static void delete_store (struct ls_expr *, basic_block); | |
695 | static void free_store_memory (void); | |
696 | static void store_motion (void); | |
697 | static void free_insn_expr_list_list (rtx *); | |
698 | static void clear_modify_mem_tables (void); | |
699 | static void free_modify_mem_tables (void); | |
700 | static rtx gcse_emit_move_after (rtx, rtx, rtx); | |
701 | static void local_cprop_find_used_regs (rtx *, void *); | |
702 | static bool do_local_cprop (rtx, rtx, int, rtx*); | |
703 | static bool adjust_libcall_notes (rtx, rtx, rtx, rtx*); | |
704 | static void local_cprop_pass (int); | |
7506f491 DE |
705 | \f |
706 | /* Entry point for global common subexpression elimination. | |
707 | F is the first instruction in the function. */ | |
708 | ||
e78d9500 | 709 | int |
1d088dee | 710 | gcse_main (rtx f, FILE *file) |
7506f491 DE |
711 | { |
712 | int changed, pass; | |
713 | /* Bytes used at start of pass. */ | |
714 | int initial_bytes_used; | |
715 | /* Maximum number of bytes used by a pass. */ | |
716 | int max_pass_bytes; | |
717 | /* Point to release obstack data from for each pass. */ | |
718 | char *gcse_obstack_bottom; | |
719 | ||
b5ce41ff JL |
720 | /* We do not construct an accurate cfg in functions which call |
721 | setjmp, so just punt to be safe. */ | |
7506f491 | 722 | if (current_function_calls_setjmp) |
e78d9500 | 723 | return 0; |
589005ff | 724 | |
b5ce41ff JL |
725 | /* Assume that we do not need to run jump optimizations after gcse. */ |
726 | run_jump_opt_after_gcse = 0; | |
727 | ||
7506f491 DE |
728 | /* For calling dump_foo fns from gdb. */ |
729 | debug_stderr = stderr; | |
b5ce41ff | 730 | gcse_file = file; |
7506f491 | 731 | |
b5ce41ff JL |
732 | /* Identify the basic block information for this function, including |
733 | successors and predecessors. */ | |
7506f491 | 734 | max_gcse_regno = max_reg_num (); |
7506f491 | 735 | |
a42cd965 AM |
736 | if (file) |
737 | dump_flow_info (file); | |
738 | ||
7506f491 | 739 | /* Return if there's nothing to do. */ |
0b17ab2f | 740 | if (n_basic_blocks <= 1) |
a18820c6 | 741 | return 0; |
7506f491 | 742 | |
55f7891b JL |
743 | /* Trying to perform global optimizations on flow graphs which have |
744 | a high connectivity will take a long time and is unlikely to be | |
745 | particularly useful. | |
746 | ||
43e72072 | 747 | In normal circumstances a cfg should have about twice as many edges |
55f7891b JL |
748 | as blocks. But we do not want to punish small functions which have |
749 | a couple switch statements. So we require a relatively large number | |
750 | of basic blocks and the ratio of edges to blocks to be high. */ | |
0b17ab2f | 751 | if (n_basic_blocks > 1000 && n_edges / n_basic_blocks >= 20) |
18424ae1 BL |
752 | { |
753 | if (warn_disabled_optimization) | |
8e42ace1 | 754 | warning ("GCSE disabled: %d > 1000 basic blocks and %d >= 20 edges/basic block", |
0b17ab2f | 755 | n_basic_blocks, n_edges / n_basic_blocks); |
18424ae1 BL |
756 | return 0; |
757 | } | |
55f7891b | 758 | |
f1fa37ff MM |
759 | /* If allocating memory for the cprop bitmap would take up too much |
760 | storage it's better just to disable the optimization. */ | |
589005ff | 761 | if ((n_basic_blocks |
f1fa37ff MM |
762 | * SBITMAP_SET_SIZE (max_gcse_regno) |
763 | * sizeof (SBITMAP_ELT_TYPE)) > MAX_GCSE_MEMORY) | |
764 | { | |
765 | if (warn_disabled_optimization) | |
766 | warning ("GCSE disabled: %d basic blocks and %d registers", | |
0b17ab2f | 767 | n_basic_blocks, max_gcse_regno); |
f1fa37ff MM |
768 | |
769 | return 0; | |
770 | } | |
771 | ||
7506f491 | 772 | gcc_obstack_init (&gcse_obstack); |
a42cd965 | 773 | bytes_used = 0; |
7506f491 | 774 | |
a13d4ebf AM |
775 | /* We need alias. */ |
776 | init_alias_analysis (); | |
c4c81601 RK |
777 | /* Record where pseudo-registers are set. This data is kept accurate |
778 | during each pass. ??? We could also record hard-reg information here | |
779 | [since it's unchanging], however it is currently done during hash table | |
780 | computation. | |
b5ce41ff | 781 | |
c4c81601 RK |
782 | It may be tempting to compute MEM set information here too, but MEM sets |
783 | will be subject to code motion one day and thus we need to compute | |
b5ce41ff | 784 | information about memory sets when we build the hash tables. */ |
7506f491 DE |
785 | |
786 | alloc_reg_set_mem (max_gcse_regno); | |
787 | compute_sets (f); | |
788 | ||
789 | pass = 0; | |
790 | initial_bytes_used = bytes_used; | |
791 | max_pass_bytes = 0; | |
792 | gcse_obstack_bottom = gcse_alloc (1); | |
793 | changed = 1; | |
740f35a0 | 794 | while (changed && pass < MAX_GCSE_PASSES) |
7506f491 DE |
795 | { |
796 | changed = 0; | |
797 | if (file) | |
798 | fprintf (file, "GCSE pass %d\n\n", pass + 1); | |
799 | ||
800 | /* Initialize bytes_used to the space for the pred/succ lists, | |
801 | and the reg_set_table data. */ | |
802 | bytes_used = initial_bytes_used; | |
803 | ||
804 | /* Each pass may create new registers, so recalculate each time. */ | |
805 | max_gcse_regno = max_reg_num (); | |
806 | ||
807 | alloc_gcse_mem (f); | |
808 | ||
b5ce41ff JL |
809 | /* Don't allow constant propagation to modify jumps |
810 | during this pass. */ | |
a0134312 | 811 | changed = one_cprop_pass (pass + 1, 0, 0); |
7506f491 DE |
812 | |
813 | if (optimize_size) | |
b5ce41ff | 814 | changed |= one_classic_gcse_pass (pass + 1); |
7506f491 | 815 | else |
589005ff | 816 | { |
a42cd965 | 817 | changed |= one_pre_gcse_pass (pass + 1); |
a13d4ebf AM |
818 | /* We may have just created new basic blocks. Release and |
819 | recompute various things which are sized on the number of | |
820 | basic blocks. */ | |
821 | if (changed) | |
822 | { | |
73991d6a | 823 | free_modify_mem_tables (); |
703ad42b | 824 | modify_mem_list = gmalloc (last_basic_block * sizeof (rtx)); |
a13d4ebf | 825 | canon_modify_mem_list |
703ad42b KG |
826 | = gmalloc (last_basic_block * sizeof (rtx)); |
827 | memset (modify_mem_list, 0, last_basic_block * sizeof (rtx)); | |
828 | memset (canon_modify_mem_list, 0, last_basic_block * sizeof (rtx)); | |
a13d4ebf | 829 | } |
a42cd965 AM |
830 | free_reg_set_mem (); |
831 | alloc_reg_set_mem (max_reg_num ()); | |
832 | compute_sets (f); | |
833 | run_jump_opt_after_gcse = 1; | |
834 | } | |
7506f491 DE |
835 | |
836 | if (max_pass_bytes < bytes_used) | |
837 | max_pass_bytes = bytes_used; | |
838 | ||
bb457bd9 JL |
839 | /* Free up memory, then reallocate for code hoisting. We can |
840 | not re-use the existing allocated memory because the tables | |
841 | will not have info for the insns or registers created by | |
842 | partial redundancy elimination. */ | |
7506f491 DE |
843 | free_gcse_mem (); |
844 | ||
bb457bd9 JL |
845 | /* It does not make sense to run code hoisting unless we optimizing |
846 | for code size -- it rarely makes programs faster, and can make | |
847 | them bigger if we did partial redundancy elimination (when optimizing | |
848 | for space, we use a classic gcse algorithm instead of partial | |
849 | redundancy algorithms). */ | |
850 | if (optimize_size) | |
589005ff | 851 | { |
bb457bd9 JL |
852 | max_gcse_regno = max_reg_num (); |
853 | alloc_gcse_mem (f); | |
854 | changed |= one_code_hoisting_pass (); | |
855 | free_gcse_mem (); | |
856 | ||
857 | if (max_pass_bytes < bytes_used) | |
858 | max_pass_bytes = bytes_used; | |
589005ff | 859 | } |
bb457bd9 | 860 | |
7506f491 DE |
861 | if (file) |
862 | { | |
863 | fprintf (file, "\n"); | |
864 | fflush (file); | |
865 | } | |
c4c81601 | 866 | |
7506f491 DE |
867 | obstack_free (&gcse_obstack, gcse_obstack_bottom); |
868 | pass++; | |
869 | } | |
870 | ||
b5ce41ff JL |
871 | /* Do one last pass of copy propagation, including cprop into |
872 | conditional jumps. */ | |
873 | ||
874 | max_gcse_regno = max_reg_num (); | |
875 | alloc_gcse_mem (f); | |
876 | /* This time, go ahead and allow cprop to alter jumps. */ | |
a0134312 | 877 | one_cprop_pass (pass + 1, 1, 0); |
b5ce41ff | 878 | free_gcse_mem (); |
7506f491 DE |
879 | |
880 | if (file) | |
881 | { | |
882 | fprintf (file, "GCSE of %s: %d basic blocks, ", | |
0b17ab2f | 883 | current_function_name, n_basic_blocks); |
7506f491 DE |
884 | fprintf (file, "%d pass%s, %d bytes\n\n", |
885 | pass, pass > 1 ? "es" : "", max_pass_bytes); | |
886 | } | |
887 | ||
6496a589 | 888 | obstack_free (&gcse_obstack, NULL); |
7506f491 | 889 | free_reg_set_mem (); |
a13d4ebf AM |
890 | /* We are finished with alias. */ |
891 | end_alias_analysis (); | |
892 | allocate_reg_info (max_reg_num (), FALSE, FALSE); | |
893 | ||
47a3dae1 | 894 | if (!optimize_size && flag_gcse_sm) |
a13d4ebf | 895 | store_motion (); |
47a3dae1 | 896 | |
a13d4ebf | 897 | /* Record where pseudo-registers are set. */ |
e78d9500 | 898 | return run_jump_opt_after_gcse; |
7506f491 DE |
899 | } |
900 | \f | |
901 | /* Misc. utilities. */ | |
902 | ||
773eae39 EB |
903 | /* Nonzero for each mode that supports (set (reg) (reg)). |
904 | This is trivially true for integer and floating point values. | |
905 | It may or may not be true for condition codes. */ | |
906 | static char can_copy[(int) NUM_MACHINE_MODES]; | |
907 | ||
7506f491 DE |
908 | /* Compute which modes support reg/reg copy operations. */ |
909 | ||
910 | static void | |
1d088dee | 911 | compute_can_copy (void) |
7506f491 DE |
912 | { |
913 | int i; | |
50b2596f | 914 | #ifndef AVOID_CCMODE_COPIES |
8e42ace1 | 915 | rtx reg, insn; |
50b2596f | 916 | #endif |
773eae39 | 917 | memset (can_copy, 0, NUM_MACHINE_MODES); |
7506f491 DE |
918 | |
919 | start_sequence (); | |
920 | for (i = 0; i < NUM_MACHINE_MODES; i++) | |
c4c81601 RK |
921 | if (GET_MODE_CLASS (i) == MODE_CC) |
922 | { | |
7506f491 | 923 | #ifdef AVOID_CCMODE_COPIES |
773eae39 | 924 | can_copy[i] = 0; |
7506f491 | 925 | #else |
c4c81601 RK |
926 | reg = gen_rtx_REG ((enum machine_mode) i, LAST_VIRTUAL_REGISTER + 1); |
927 | insn = emit_insn (gen_rtx_SET (VOIDmode, reg, reg)); | |
9714cf43 | 928 | if (recog (PATTERN (insn), insn, NULL) >= 0) |
773eae39 | 929 | can_copy[i] = 1; |
7506f491 | 930 | #endif |
c4c81601 | 931 | } |
141b5810 | 932 | else |
773eae39 | 933 | can_copy[i] = 1; |
c4c81601 | 934 | |
7506f491 | 935 | end_sequence (); |
7506f491 | 936 | } |
773eae39 EB |
937 | |
938 | /* Returns whether the mode supports reg/reg copy operations. */ | |
939 | ||
940 | bool | |
1d088dee | 941 | can_copy_p (enum machine_mode mode) |
773eae39 EB |
942 | { |
943 | static bool can_copy_init_p = false; | |
944 | ||
945 | if (! can_copy_init_p) | |
946 | { | |
947 | compute_can_copy (); | |
948 | can_copy_init_p = true; | |
949 | } | |
950 | ||
951 | return can_copy[mode] != 0; | |
952 | } | |
7506f491 DE |
953 | \f |
954 | /* Cover function to xmalloc to record bytes allocated. */ | |
955 | ||
703ad42b | 956 | static void * |
1d088dee | 957 | gmalloc (unsigned int size) |
7506f491 DE |
958 | { |
959 | bytes_used += size; | |
960 | return xmalloc (size); | |
961 | } | |
962 | ||
963 | /* Cover function to xrealloc. | |
964 | We don't record the additional size since we don't know it. | |
965 | It won't affect memory usage stats much anyway. */ | |
966 | ||
703ad42b KG |
967 | static void * |
968 | grealloc (void *ptr, unsigned int size) | |
7506f491 DE |
969 | { |
970 | return xrealloc (ptr, size); | |
971 | } | |
972 | ||
77bbd421 | 973 | /* Cover function to obstack_alloc. */ |
7506f491 | 974 | |
703ad42b | 975 | static void * |
1d088dee | 976 | gcse_alloc (unsigned long size) |
7506f491 | 977 | { |
77bbd421 | 978 | bytes_used += size; |
703ad42b | 979 | return obstack_alloc (&gcse_obstack, size); |
7506f491 DE |
980 | } |
981 | ||
982 | /* Allocate memory for the cuid mapping array, | |
983 | and reg/memory set tracking tables. | |
984 | ||
985 | This is called at the start of each pass. */ | |
986 | ||
987 | static void | |
1d088dee | 988 | alloc_gcse_mem (rtx f) |
7506f491 | 989 | { |
8e42ace1 | 990 | int i, n; |
7506f491 DE |
991 | rtx insn; |
992 | ||
993 | /* Find the largest UID and create a mapping from UIDs to CUIDs. | |
994 | CUIDs are like UIDs except they increase monotonically, have no gaps, | |
995 | and only apply to real insns. */ | |
996 | ||
997 | max_uid = get_max_uid (); | |
998 | n = (max_uid + 1) * sizeof (int); | |
703ad42b KG |
999 | uid_cuid = gmalloc (n); |
1000 | memset (uid_cuid, 0, n); | |
7506f491 DE |
1001 | for (insn = f, i = 0; insn; insn = NEXT_INSN (insn)) |
1002 | { | |
2c3c49de | 1003 | if (INSN_P (insn)) |
b86db3eb | 1004 | uid_cuid[INSN_UID (insn)] = i++; |
7506f491 | 1005 | else |
b86db3eb | 1006 | uid_cuid[INSN_UID (insn)] = i; |
7506f491 DE |
1007 | } |
1008 | ||
1009 | /* Create a table mapping cuids to insns. */ | |
1010 | ||
1011 | max_cuid = i; | |
1012 | n = (max_cuid + 1) * sizeof (rtx); | |
703ad42b KG |
1013 | cuid_insn = gmalloc (n); |
1014 | memset (cuid_insn, 0, n); | |
7506f491 | 1015 | for (insn = f, i = 0; insn; insn = NEXT_INSN (insn)) |
2c3c49de | 1016 | if (INSN_P (insn)) |
c4c81601 | 1017 | CUID_INSN (i++) = insn; |
7506f491 DE |
1018 | |
1019 | /* Allocate vars to track sets of regs. */ | |
73991d6a | 1020 | reg_set_bitmap = BITMAP_XMALLOC (); |
7506f491 DE |
1021 | |
1022 | /* Allocate vars to track sets of regs, memory per block. */ | |
703ad42b | 1023 | reg_set_in_block = sbitmap_vector_alloc (last_basic_block, max_gcse_regno); |
a13d4ebf AM |
1024 | /* Allocate array to keep a list of insns which modify memory in each |
1025 | basic block. */ | |
703ad42b KG |
1026 | modify_mem_list = gmalloc (last_basic_block * sizeof (rtx)); |
1027 | canon_modify_mem_list = gmalloc (last_basic_block * sizeof (rtx)); | |
1028 | memset (modify_mem_list, 0, last_basic_block * sizeof (rtx)); | |
1029 | memset (canon_modify_mem_list, 0, last_basic_block * sizeof (rtx)); | |
73991d6a JH |
1030 | modify_mem_list_set = BITMAP_XMALLOC (); |
1031 | canon_modify_mem_list_set = BITMAP_XMALLOC (); | |
7506f491 DE |
1032 | } |
1033 | ||
1034 | /* Free memory allocated by alloc_gcse_mem. */ | |
1035 | ||
1036 | static void | |
1d088dee | 1037 | free_gcse_mem (void) |
7506f491 DE |
1038 | { |
1039 | free (uid_cuid); | |
1040 | free (cuid_insn); | |
1041 | ||
73991d6a | 1042 | BITMAP_XFREE (reg_set_bitmap); |
7506f491 | 1043 | |
5a660bff | 1044 | sbitmap_vector_free (reg_set_in_block); |
73991d6a JH |
1045 | free_modify_mem_tables (); |
1046 | BITMAP_XFREE (modify_mem_list_set); | |
1047 | BITMAP_XFREE (canon_modify_mem_list_set); | |
7506f491 DE |
1048 | } |
1049 | ||
0511851c MM |
1050 | /* Many of the global optimization algorithms work by solving dataflow |
1051 | equations for various expressions. Initially, some local value is | |
c4c81601 RK |
1052 | computed for each expression in each block. Then, the values across the |
1053 | various blocks are combined (by following flow graph edges) to arrive at | |
1054 | global values. Conceptually, each set of equations is independent. We | |
1055 | may therefore solve all the equations in parallel, solve them one at a | |
1056 | time, or pick any intermediate approach. | |
1057 | ||
1058 | When you're going to need N two-dimensional bitmaps, each X (say, the | |
1059 | number of blocks) by Y (say, the number of expressions), call this | |
1060 | function. It's not important what X and Y represent; only that Y | |
1061 | correspond to the things that can be done in parallel. This function will | |
1062 | return an appropriate chunking factor C; you should solve C sets of | |
1063 | equations in parallel. By going through this function, we can easily | |
1064 | trade space against time; by solving fewer equations in parallel we use | |
1065 | less space. */ | |
0511851c MM |
1066 | |
1067 | static int | |
1d088dee | 1068 | get_bitmap_width (int n, int x, int y) |
0511851c MM |
1069 | { |
1070 | /* It's not really worth figuring out *exactly* how much memory will | |
1071 | be used by a particular choice. The important thing is to get | |
1072 | something approximately right. */ | |
1073 | size_t max_bitmap_memory = 10 * 1024 * 1024; | |
1074 | ||
1075 | /* The number of bytes we'd use for a single column of minimum | |
1076 | width. */ | |
1077 | size_t column_size = n * x * sizeof (SBITMAP_ELT_TYPE); | |
1078 | ||
1079 | /* Often, it's reasonable just to solve all the equations in | |
1080 | parallel. */ | |
1081 | if (column_size * SBITMAP_SET_SIZE (y) <= max_bitmap_memory) | |
1082 | return y; | |
1083 | ||
1084 | /* Otherwise, pick the largest width we can, without going over the | |
1085 | limit. */ | |
1086 | return SBITMAP_ELT_BITS * ((max_bitmap_memory + column_size - 1) | |
1087 | / column_size); | |
1088 | } | |
b5ce41ff JL |
1089 | \f |
1090 | /* Compute the local properties of each recorded expression. | |
c4c81601 RK |
1091 | |
1092 | Local properties are those that are defined by the block, irrespective of | |
1093 | other blocks. | |
b5ce41ff JL |
1094 | |
1095 | An expression is transparent in a block if its operands are not modified | |
1096 | in the block. | |
1097 | ||
1098 | An expression is computed (locally available) in a block if it is computed | |
1099 | at least once and expression would contain the same value if the | |
1100 | computation was moved to the end of the block. | |
1101 | ||
1102 | An expression is locally anticipatable in a block if it is computed at | |
1103 | least once and expression would contain the same value if the computation | |
1104 | was moved to the beginning of the block. | |
1105 | ||
c4c81601 RK |
1106 | We call this routine for cprop, pre and code hoisting. They all compute |
1107 | basically the same information and thus can easily share this code. | |
7506f491 | 1108 | |
c4c81601 RK |
1109 | TRANSP, COMP, and ANTLOC are destination sbitmaps for recording local |
1110 | properties. If NULL, then it is not necessary to compute or record that | |
1111 | particular property. | |
b5ce41ff | 1112 | |
02280659 ZD |
1113 | TABLE controls which hash table to look at. If it is set hash table, |
1114 | additionally, TRANSP is computed as ~TRANSP, since this is really cprop's | |
c4c81601 | 1115 | ABSALTERED. */ |
589005ff | 1116 | |
b5ce41ff | 1117 | static void |
1d088dee | 1118 | compute_local_properties (sbitmap *transp, sbitmap *comp, sbitmap *antloc, struct hash_table *table) |
b5ce41ff | 1119 | { |
02280659 | 1120 | unsigned int i; |
589005ff | 1121 | |
b5ce41ff JL |
1122 | /* Initialize any bitmaps that were passed in. */ |
1123 | if (transp) | |
695ab36a | 1124 | { |
02280659 | 1125 | if (table->set_p) |
d55bc081 | 1126 | sbitmap_vector_zero (transp, last_basic_block); |
695ab36a | 1127 | else |
d55bc081 | 1128 | sbitmap_vector_ones (transp, last_basic_block); |
695ab36a | 1129 | } |
c4c81601 | 1130 | |
b5ce41ff | 1131 | if (comp) |
d55bc081 | 1132 | sbitmap_vector_zero (comp, last_basic_block); |
b5ce41ff | 1133 | if (antloc) |
d55bc081 | 1134 | sbitmap_vector_zero (antloc, last_basic_block); |
b5ce41ff | 1135 | |
02280659 | 1136 | for (i = 0; i < table->size; i++) |
7506f491 | 1137 | { |
b5ce41ff JL |
1138 | struct expr *expr; |
1139 | ||
02280659 | 1140 | for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash) |
b5ce41ff | 1141 | { |
b5ce41ff | 1142 | int indx = expr->bitmap_index; |
c4c81601 | 1143 | struct occr *occr; |
b5ce41ff JL |
1144 | |
1145 | /* The expression is transparent in this block if it is not killed. | |
1146 | We start by assuming all are transparent [none are killed], and | |
1147 | then reset the bits for those that are. */ | |
b5ce41ff | 1148 | if (transp) |
02280659 | 1149 | compute_transp (expr->expr, indx, transp, table->set_p); |
b5ce41ff JL |
1150 | |
1151 | /* The occurrences recorded in antic_occr are exactly those that | |
cc2902df | 1152 | we want to set to nonzero in ANTLOC. */ |
b5ce41ff | 1153 | if (antloc) |
c4c81601 RK |
1154 | for (occr = expr->antic_occr; occr != NULL; occr = occr->next) |
1155 | { | |
1156 | SET_BIT (antloc[BLOCK_NUM (occr->insn)], indx); | |
b5ce41ff | 1157 | |
c4c81601 RK |
1158 | /* While we're scanning the table, this is a good place to |
1159 | initialize this. */ | |
1160 | occr->deleted_p = 0; | |
1161 | } | |
b5ce41ff JL |
1162 | |
1163 | /* The occurrences recorded in avail_occr are exactly those that | |
cc2902df | 1164 | we want to set to nonzero in COMP. */ |
b5ce41ff | 1165 | if (comp) |
c4c81601 RK |
1166 | for (occr = expr->avail_occr; occr != NULL; occr = occr->next) |
1167 | { | |
1168 | SET_BIT (comp[BLOCK_NUM (occr->insn)], indx); | |
b5ce41ff | 1169 | |
c4c81601 RK |
1170 | /* While we're scanning the table, this is a good place to |
1171 | initialize this. */ | |
1172 | occr->copied_p = 0; | |
1173 | } | |
b5ce41ff JL |
1174 | |
1175 | /* While we're scanning the table, this is a good place to | |
1176 | initialize this. */ | |
1177 | expr->reaching_reg = 0; | |
1178 | } | |
7506f491 | 1179 | } |
7506f491 DE |
1180 | } |
1181 | \f | |
1182 | /* Register set information. | |
1183 | ||
1184 | `reg_set_table' records where each register is set or otherwise | |
1185 | modified. */ | |
1186 | ||
1187 | static struct obstack reg_set_obstack; | |
1188 | ||
1189 | static void | |
1d088dee | 1190 | alloc_reg_set_mem (int n_regs) |
7506f491 | 1191 | { |
c4c81601 | 1192 | unsigned int n; |
7506f491 DE |
1193 | |
1194 | reg_set_table_size = n_regs + REG_SET_TABLE_SLOP; | |
1195 | n = reg_set_table_size * sizeof (struct reg_set *); | |
703ad42b KG |
1196 | reg_set_table = gmalloc (n); |
1197 | memset (reg_set_table, 0, n); | |
7506f491 DE |
1198 | |
1199 | gcc_obstack_init (®_set_obstack); | |
1200 | } | |
1201 | ||
1202 | static void | |
1d088dee | 1203 | free_reg_set_mem (void) |
7506f491 DE |
1204 | { |
1205 | free (reg_set_table); | |
6496a589 | 1206 | obstack_free (®_set_obstack, NULL); |
7506f491 DE |
1207 | } |
1208 | ||
1209 | /* Record REGNO in the reg_set table. */ | |
1210 | ||
1211 | static void | |
1d088dee | 1212 | record_one_set (int regno, rtx insn) |
7506f491 | 1213 | { |
172890a2 | 1214 | /* Allocate a new reg_set element and link it onto the list. */ |
63bc1d05 | 1215 | struct reg_set *new_reg_info; |
7506f491 DE |
1216 | |
1217 | /* If the table isn't big enough, enlarge it. */ | |
1218 | if (regno >= reg_set_table_size) | |
1219 | { | |
1220 | int new_size = regno + REG_SET_TABLE_SLOP; | |
c4c81601 | 1221 | |
703ad42b KG |
1222 | reg_set_table = grealloc (reg_set_table, |
1223 | new_size * sizeof (struct reg_set *)); | |
1224 | memset (reg_set_table + reg_set_table_size, 0, | |
8e42ace1 | 1225 | (new_size - reg_set_table_size) * sizeof (struct reg_set *)); |
7506f491 DE |
1226 | reg_set_table_size = new_size; |
1227 | } | |
1228 | ||
703ad42b | 1229 | new_reg_info = obstack_alloc (®_set_obstack, sizeof (struct reg_set)); |
7506f491 DE |
1230 | bytes_used += sizeof (struct reg_set); |
1231 | new_reg_info->insn = insn; | |
274969ea MM |
1232 | new_reg_info->next = reg_set_table[regno]; |
1233 | reg_set_table[regno] = new_reg_info; | |
7506f491 DE |
1234 | } |
1235 | ||
c4c81601 RK |
1236 | /* Called from compute_sets via note_stores to handle one SET or CLOBBER in |
1237 | an insn. The DATA is really the instruction in which the SET is | |
1238 | occurring. */ | |
7506f491 DE |
1239 | |
1240 | static void | |
1d088dee | 1241 | record_set_info (rtx dest, rtx setter ATTRIBUTE_UNUSED, void *data) |
7506f491 | 1242 | { |
84832317 MM |
1243 | rtx record_set_insn = (rtx) data; |
1244 | ||
c4c81601 RK |
1245 | if (GET_CODE (dest) == REG && REGNO (dest) >= FIRST_PSEUDO_REGISTER) |
1246 | record_one_set (REGNO (dest), record_set_insn); | |
7506f491 DE |
1247 | } |
1248 | ||
1249 | /* Scan the function and record each set of each pseudo-register. | |
1250 | ||
c4c81601 | 1251 | This is called once, at the start of the gcse pass. See the comments for |
fbe5a4a6 | 1252 | `reg_set_table' for further documentation. */ |
7506f491 DE |
1253 | |
1254 | static void | |
1d088dee | 1255 | compute_sets (rtx f) |
7506f491 | 1256 | { |
c4c81601 | 1257 | rtx insn; |
7506f491 | 1258 | |
c4c81601 | 1259 | for (insn = f; insn != 0; insn = NEXT_INSN (insn)) |
2c3c49de | 1260 | if (INSN_P (insn)) |
c4c81601 | 1261 | note_stores (PATTERN (insn), record_set_info, insn); |
7506f491 DE |
1262 | } |
1263 | \f | |
1264 | /* Hash table support. */ | |
1265 | ||
80c29cc4 RZ |
1266 | struct reg_avail_info |
1267 | { | |
e0082a72 | 1268 | basic_block last_bb; |
80c29cc4 RZ |
1269 | int first_set; |
1270 | int last_set; | |
1271 | }; | |
1272 | ||
1273 | static struct reg_avail_info *reg_avail_info; | |
e0082a72 | 1274 | static basic_block current_bb; |
7506f491 | 1275 | |
7506f491 | 1276 | |
fb0c0a12 RK |
1277 | /* See whether X, the source of a set, is something we want to consider for |
1278 | GCSE. */ | |
7506f491 | 1279 | |
e2500fed | 1280 | static GTY(()) rtx test_insn; |
7506f491 | 1281 | static int |
1d088dee | 1282 | want_to_gcse_p (rtx x) |
7506f491 | 1283 | { |
fb0c0a12 RK |
1284 | int num_clobbers = 0; |
1285 | int icode; | |
1286 | ||
c4c81601 | 1287 | switch (GET_CODE (x)) |
7506f491 DE |
1288 | { |
1289 | case REG: | |
1290 | case SUBREG: | |
1291 | case CONST_INT: | |
1292 | case CONST_DOUBLE: | |
69ef87e2 | 1293 | case CONST_VECTOR: |
7506f491 | 1294 | case CALL: |
34ee7f82 | 1295 | case CONSTANT_P_RTX: |
7506f491 DE |
1296 | return 0; |
1297 | ||
1298 | default: | |
1299 | break; | |
1300 | } | |
1301 | ||
fb0c0a12 RK |
1302 | /* If this is a valid operand, we are OK. If it's VOIDmode, we aren't. */ |
1303 | if (general_operand (x, GET_MODE (x))) | |
1304 | return 1; | |
1305 | else if (GET_MODE (x) == VOIDmode) | |
1306 | return 0; | |
1307 | ||
1308 | /* Otherwise, check if we can make a valid insn from it. First initialize | |
1309 | our test insn if we haven't already. */ | |
1310 | if (test_insn == 0) | |
1311 | { | |
1312 | test_insn | |
1313 | = make_insn_raw (gen_rtx_SET (VOIDmode, | |
1314 | gen_rtx_REG (word_mode, | |
1315 | FIRST_PSEUDO_REGISTER * 2), | |
1316 | const0_rtx)); | |
1317 | NEXT_INSN (test_insn) = PREV_INSN (test_insn) = 0; | |
fb0c0a12 RK |
1318 | } |
1319 | ||
1320 | /* Now make an insn like the one we would make when GCSE'ing and see if | |
1321 | valid. */ | |
1322 | PUT_MODE (SET_DEST (PATTERN (test_insn)), GET_MODE (x)); | |
1323 | SET_SRC (PATTERN (test_insn)) = x; | |
1324 | return ((icode = recog (PATTERN (test_insn), test_insn, &num_clobbers)) >= 0 | |
1325 | && (num_clobbers == 0 || ! added_clobbers_hard_reg_p (icode))); | |
7506f491 DE |
1326 | } |
1327 | ||
cc2902df | 1328 | /* Return nonzero if the operands of expression X are unchanged from the |
7506f491 DE |
1329 | start of INSN's basic block up to but not including INSN (if AVAIL_P == 0), |
1330 | or from INSN to the end of INSN's basic block (if AVAIL_P != 0). */ | |
1331 | ||
1332 | static int | |
1d088dee | 1333 | oprs_unchanged_p (rtx x, rtx insn, int avail_p) |
7506f491 | 1334 | { |
c4c81601 | 1335 | int i, j; |
7506f491 | 1336 | enum rtx_code code; |
6f7d635c | 1337 | const char *fmt; |
7506f491 | 1338 | |
7506f491 DE |
1339 | if (x == 0) |
1340 | return 1; | |
1341 | ||
1342 | code = GET_CODE (x); | |
1343 | switch (code) | |
1344 | { | |
1345 | case REG: | |
80c29cc4 RZ |
1346 | { |
1347 | struct reg_avail_info *info = ®_avail_info[REGNO (x)]; | |
1348 | ||
1349 | if (info->last_bb != current_bb) | |
1350 | return 1; | |
589005ff | 1351 | if (avail_p) |
80c29cc4 RZ |
1352 | return info->last_set < INSN_CUID (insn); |
1353 | else | |
1354 | return info->first_set >= INSN_CUID (insn); | |
1355 | } | |
7506f491 DE |
1356 | |
1357 | case MEM: | |
e0082a72 | 1358 | if (load_killed_in_block_p (current_bb, INSN_CUID (insn), |
a13d4ebf AM |
1359 | x, avail_p)) |
1360 | return 0; | |
7506f491 | 1361 | else |
c4c81601 | 1362 | return oprs_unchanged_p (XEXP (x, 0), insn, avail_p); |
7506f491 DE |
1363 | |
1364 | case PRE_DEC: | |
1365 | case PRE_INC: | |
1366 | case POST_DEC: | |
1367 | case POST_INC: | |
4b983fdc RH |
1368 | case PRE_MODIFY: |
1369 | case POST_MODIFY: | |
7506f491 DE |
1370 | return 0; |
1371 | ||
1372 | case PC: | |
1373 | case CC0: /*FIXME*/ | |
1374 | case CONST: | |
1375 | case CONST_INT: | |
1376 | case CONST_DOUBLE: | |
69ef87e2 | 1377 | case CONST_VECTOR: |
7506f491 DE |
1378 | case SYMBOL_REF: |
1379 | case LABEL_REF: | |
1380 | case ADDR_VEC: | |
1381 | case ADDR_DIFF_VEC: | |
1382 | return 1; | |
1383 | ||
1384 | default: | |
1385 | break; | |
1386 | } | |
1387 | ||
c4c81601 | 1388 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
7506f491 DE |
1389 | { |
1390 | if (fmt[i] == 'e') | |
1391 | { | |
c4c81601 RK |
1392 | /* If we are about to do the last recursive call needed at this |
1393 | level, change it into iteration. This function is called enough | |
1394 | to be worth it. */ | |
7506f491 | 1395 | if (i == 0) |
c4c81601 RK |
1396 | return oprs_unchanged_p (XEXP (x, i), insn, avail_p); |
1397 | ||
1398 | else if (! oprs_unchanged_p (XEXP (x, i), insn, avail_p)) | |
7506f491 DE |
1399 | return 0; |
1400 | } | |
1401 | else if (fmt[i] == 'E') | |
c4c81601 RK |
1402 | for (j = 0; j < XVECLEN (x, i); j++) |
1403 | if (! oprs_unchanged_p (XVECEXP (x, i, j), insn, avail_p)) | |
1404 | return 0; | |
7506f491 DE |
1405 | } |
1406 | ||
1407 | return 1; | |
1408 | } | |
1409 | ||
a13d4ebf AM |
1410 | /* Used for communication between mems_conflict_for_gcse_p and |
1411 | load_killed_in_block_p. Nonzero if mems_conflict_for_gcse_p finds a | |
1412 | conflict between two memory references. */ | |
1413 | static int gcse_mems_conflict_p; | |
1414 | ||
1415 | /* Used for communication between mems_conflict_for_gcse_p and | |
1416 | load_killed_in_block_p. A memory reference for a load instruction, | |
1417 | mems_conflict_for_gcse_p will see if a memory store conflicts with | |
1418 | this memory load. */ | |
1419 | static rtx gcse_mem_operand; | |
1420 | ||
1421 | /* DEST is the output of an instruction. If it is a memory reference, and | |
1422 | possibly conflicts with the load found in gcse_mem_operand, then set | |
1423 | gcse_mems_conflict_p to a nonzero value. */ | |
1424 | ||
1425 | static void | |
1d088dee AJ |
1426 | mems_conflict_for_gcse_p (rtx dest, rtx setter ATTRIBUTE_UNUSED, |
1427 | void *data ATTRIBUTE_UNUSED) | |
a13d4ebf AM |
1428 | { |
1429 | while (GET_CODE (dest) == SUBREG | |
1430 | || GET_CODE (dest) == ZERO_EXTRACT | |
1431 | || GET_CODE (dest) == SIGN_EXTRACT | |
1432 | || GET_CODE (dest) == STRICT_LOW_PART) | |
1433 | dest = XEXP (dest, 0); | |
1434 | ||
1435 | /* If DEST is not a MEM, then it will not conflict with the load. Note | |
1436 | that function calls are assumed to clobber memory, but are handled | |
1437 | elsewhere. */ | |
1438 | if (GET_CODE (dest) != MEM) | |
1439 | return; | |
aaa4ca30 | 1440 | |
a13d4ebf | 1441 | /* If we are setting a MEM in our list of specially recognized MEMs, |
589005ff KH |
1442 | don't mark as killed this time. */ |
1443 | ||
47a3dae1 | 1444 | if (expr_equiv_p (dest, gcse_mem_operand) && pre_ldst_mems != NULL) |
a13d4ebf AM |
1445 | { |
1446 | if (!find_rtx_in_ldst (dest)) | |
1447 | gcse_mems_conflict_p = 1; | |
1448 | return; | |
1449 | } | |
aaa4ca30 | 1450 | |
a13d4ebf AM |
1451 | if (true_dependence (dest, GET_MODE (dest), gcse_mem_operand, |
1452 | rtx_addr_varies_p)) | |
1453 | gcse_mems_conflict_p = 1; | |
1454 | } | |
1455 | ||
1456 | /* Return nonzero if the expression in X (a memory reference) is killed | |
1457 | in block BB before or after the insn with the CUID in UID_LIMIT. | |
1458 | AVAIL_P is nonzero for kills after UID_LIMIT, and zero for kills | |
1459 | before UID_LIMIT. | |
1460 | ||
1461 | To check the entire block, set UID_LIMIT to max_uid + 1 and | |
1462 | AVAIL_P to 0. */ | |
1463 | ||
1464 | static int | |
1d088dee | 1465 | load_killed_in_block_p (basic_block bb, int uid_limit, rtx x, int avail_p) |
a13d4ebf | 1466 | { |
0b17ab2f | 1467 | rtx list_entry = modify_mem_list[bb->index]; |
a13d4ebf AM |
1468 | while (list_entry) |
1469 | { | |
1470 | rtx setter; | |
1471 | /* Ignore entries in the list that do not apply. */ | |
1472 | if ((avail_p | |
1473 | && INSN_CUID (XEXP (list_entry, 0)) < uid_limit) | |
1474 | || (! avail_p | |
1475 | && INSN_CUID (XEXP (list_entry, 0)) > uid_limit)) | |
1476 | { | |
1477 | list_entry = XEXP (list_entry, 1); | |
1478 | continue; | |
1479 | } | |
1480 | ||
1481 | setter = XEXP (list_entry, 0); | |
1482 | ||
1483 | /* If SETTER is a call everything is clobbered. Note that calls | |
1484 | to pure functions are never put on the list, so we need not | |
1485 | worry about them. */ | |
1486 | if (GET_CODE (setter) == CALL_INSN) | |
1487 | return 1; | |
1488 | ||
1489 | /* SETTER must be an INSN of some kind that sets memory. Call | |
589005ff | 1490 | note_stores to examine each hunk of memory that is modified. |
a13d4ebf AM |
1491 | |
1492 | The note_stores interface is pretty limited, so we have to | |
1493 | communicate via global variables. Yuk. */ | |
1494 | gcse_mem_operand = x; | |
1495 | gcse_mems_conflict_p = 0; | |
1496 | note_stores (PATTERN (setter), mems_conflict_for_gcse_p, NULL); | |
1497 | if (gcse_mems_conflict_p) | |
1498 | return 1; | |
1499 | list_entry = XEXP (list_entry, 1); | |
1500 | } | |
1501 | return 0; | |
1502 | } | |
1503 | ||
cc2902df | 1504 | /* Return nonzero if the operands of expression X are unchanged from |
7506f491 DE |
1505 | the start of INSN's basic block up to but not including INSN. */ |
1506 | ||
1507 | static int | |
1d088dee | 1508 | oprs_anticipatable_p (rtx x, rtx insn) |
7506f491 DE |
1509 | { |
1510 | return oprs_unchanged_p (x, insn, 0); | |
1511 | } | |
1512 | ||
cc2902df | 1513 | /* Return nonzero if the operands of expression X are unchanged from |
7506f491 DE |
1514 | INSN to the end of INSN's basic block. */ |
1515 | ||
1516 | static int | |
1d088dee | 1517 | oprs_available_p (rtx x, rtx insn) |
7506f491 DE |
1518 | { |
1519 | return oprs_unchanged_p (x, insn, 1); | |
1520 | } | |
1521 | ||
1522 | /* Hash expression X. | |
c4c81601 RK |
1523 | |
1524 | MODE is only used if X is a CONST_INT. DO_NOT_RECORD_P is a boolean | |
1525 | indicating if a volatile operand is found or if the expression contains | |
1526 | something we don't want to insert in the table. | |
7506f491 DE |
1527 | |
1528 | ??? One might want to merge this with canon_hash. Later. */ | |
1529 | ||
1530 | static unsigned int | |
1d088dee | 1531 | hash_expr (rtx x, enum machine_mode mode, int *do_not_record_p, int hash_table_size) |
7506f491 DE |
1532 | { |
1533 | unsigned int hash; | |
1534 | ||
1535 | *do_not_record_p = 0; | |
1536 | ||
1537 | hash = hash_expr_1 (x, mode, do_not_record_p); | |
1538 | return hash % hash_table_size; | |
1539 | } | |
172890a2 | 1540 | |
6462bb43 | 1541 | /* Hash a string. Just add its bytes up. */ |
172890a2 | 1542 | |
6462bb43 | 1543 | static inline unsigned |
1d088dee | 1544 | hash_string_1 (const char *ps) |
6462bb43 AO |
1545 | { |
1546 | unsigned hash = 0; | |
8e42ace1 | 1547 | const unsigned char *p = (const unsigned char *) ps; |
589005ff | 1548 | |
6462bb43 AO |
1549 | if (p) |
1550 | while (*p) | |
1551 | hash += *p++; | |
1552 | ||
1553 | return hash; | |
1554 | } | |
7506f491 DE |
1555 | |
1556 | /* Subroutine of hash_expr to do the actual work. */ | |
1557 | ||
1558 | static unsigned int | |
1d088dee | 1559 | hash_expr_1 (rtx x, enum machine_mode mode, int *do_not_record_p) |
7506f491 DE |
1560 | { |
1561 | int i, j; | |
1562 | unsigned hash = 0; | |
1563 | enum rtx_code code; | |
6f7d635c | 1564 | const char *fmt; |
7506f491 | 1565 | |
c4c81601 | 1566 | /* Used to turn recursion into iteration. We can't rely on GCC's |
fbe5a4a6 | 1567 | tail-recursion elimination since we need to keep accumulating values |
c4c81601 | 1568 | in HASH. */ |
7506f491 DE |
1569 | |
1570 | if (x == 0) | |
1571 | return hash; | |
1572 | ||
c4c81601 | 1573 | repeat: |
7506f491 DE |
1574 | code = GET_CODE (x); |
1575 | switch (code) | |
1576 | { | |
1577 | case REG: | |
c4c81601 RK |
1578 | hash += ((unsigned int) REG << 7) + REGNO (x); |
1579 | return hash; | |
7506f491 DE |
1580 | |
1581 | case CONST_INT: | |
c4c81601 RK |
1582 | hash += (((unsigned int) CONST_INT << 7) + (unsigned int) mode |
1583 | + (unsigned int) INTVAL (x)); | |
1584 | return hash; | |
7506f491 DE |
1585 | |
1586 | case CONST_DOUBLE: | |
1587 | /* This is like the general case, except that it only counts | |
1588 | the integers representing the constant. */ | |
c4c81601 | 1589 | hash += (unsigned int) code + (unsigned int) GET_MODE (x); |
7506f491 DE |
1590 | if (GET_MODE (x) != VOIDmode) |
1591 | for (i = 2; i < GET_RTX_LENGTH (CONST_DOUBLE); i++) | |
c4c81601 | 1592 | hash += (unsigned int) XWINT (x, i); |
7506f491 | 1593 | else |
c4c81601 RK |
1594 | hash += ((unsigned int) CONST_DOUBLE_LOW (x) |
1595 | + (unsigned int) CONST_DOUBLE_HIGH (x)); | |
7506f491 DE |
1596 | return hash; |
1597 | ||
69ef87e2 AH |
1598 | case CONST_VECTOR: |
1599 | { | |
1600 | int units; | |
1601 | rtx elt; | |
1602 | ||
1603 | units = CONST_VECTOR_NUNITS (x); | |
1604 | ||
1605 | for (i = 0; i < units; ++i) | |
1606 | { | |
1607 | elt = CONST_VECTOR_ELT (x, i); | |
1608 | hash += hash_expr_1 (elt, GET_MODE (elt), do_not_record_p); | |
1609 | } | |
1610 | ||
1611 | return hash; | |
1612 | } | |
1613 | ||
7506f491 DE |
1614 | /* Assume there is only one rtx object for any given label. */ |
1615 | case LABEL_REF: | |
1616 | /* We don't hash on the address of the CODE_LABEL to avoid bootstrap | |
1617 | differences and differences between each stage's debugging dumps. */ | |
c4c81601 RK |
1618 | hash += (((unsigned int) LABEL_REF << 7) |
1619 | + CODE_LABEL_NUMBER (XEXP (x, 0))); | |
7506f491 DE |
1620 | return hash; |
1621 | ||
1622 | case SYMBOL_REF: | |
1623 | { | |
1624 | /* Don't hash on the symbol's address to avoid bootstrap differences. | |
1625 | Different hash values may cause expressions to be recorded in | |
1626 | different orders and thus different registers to be used in the | |
1627 | final assembler. This also avoids differences in the dump files | |
1628 | between various stages. */ | |
1629 | unsigned int h = 0; | |
3cce094d | 1630 | const unsigned char *p = (const unsigned char *) XSTR (x, 0); |
c4c81601 | 1631 | |
7506f491 DE |
1632 | while (*p) |
1633 | h += (h << 7) + *p++; /* ??? revisit */ | |
c4c81601 RK |
1634 | |
1635 | hash += ((unsigned int) SYMBOL_REF << 7) + h; | |
7506f491 DE |
1636 | return hash; |
1637 | } | |
1638 | ||
1639 | case MEM: | |
1640 | if (MEM_VOLATILE_P (x)) | |
1641 | { | |
1642 | *do_not_record_p = 1; | |
1643 | return 0; | |
1644 | } | |
c4c81601 RK |
1645 | |
1646 | hash += (unsigned int) MEM; | |
d51f3632 JH |
1647 | /* We used alias set for hashing, but this is not good, since the alias |
1648 | set may differ in -fprofile-arcs and -fbranch-probabilities compilation | |
1649 | causing the profiles to fail to match. */ | |
7506f491 DE |
1650 | x = XEXP (x, 0); |
1651 | goto repeat; | |
1652 | ||
1653 | case PRE_DEC: | |
1654 | case PRE_INC: | |
1655 | case POST_DEC: | |
1656 | case POST_INC: | |
1657 | case PC: | |
1658 | case CC0: | |
1659 | case CALL: | |
1660 | case UNSPEC_VOLATILE: | |
1661 | *do_not_record_p = 1; | |
1662 | return 0; | |
1663 | ||
1664 | case ASM_OPERANDS: | |
1665 | if (MEM_VOLATILE_P (x)) | |
1666 | { | |
1667 | *do_not_record_p = 1; | |
1668 | return 0; | |
1669 | } | |
6462bb43 AO |
1670 | else |
1671 | { | |
1672 | /* We don't want to take the filename and line into account. */ | |
1673 | hash += (unsigned) code + (unsigned) GET_MODE (x) | |
1674 | + hash_string_1 (ASM_OPERANDS_TEMPLATE (x)) | |
1675 | + hash_string_1 (ASM_OPERANDS_OUTPUT_CONSTRAINT (x)) | |
1676 | + (unsigned) ASM_OPERANDS_OUTPUT_IDX (x); | |
1677 | ||
1678 | if (ASM_OPERANDS_INPUT_LENGTH (x)) | |
1679 | { | |
1680 | for (i = 1; i < ASM_OPERANDS_INPUT_LENGTH (x); i++) | |
1681 | { | |
1682 | hash += (hash_expr_1 (ASM_OPERANDS_INPUT (x, i), | |
1683 | GET_MODE (ASM_OPERANDS_INPUT (x, i)), | |
1684 | do_not_record_p) | |
1685 | + hash_string_1 (ASM_OPERANDS_INPUT_CONSTRAINT | |
1686 | (x, i))); | |
1687 | } | |
1688 | ||
1689 | hash += hash_string_1 (ASM_OPERANDS_INPUT_CONSTRAINT (x, 0)); | |
1690 | x = ASM_OPERANDS_INPUT (x, 0); | |
1691 | mode = GET_MODE (x); | |
1692 | goto repeat; | |
1693 | } | |
1694 | return hash; | |
1695 | } | |
7506f491 DE |
1696 | |
1697 | default: | |
1698 | break; | |
1699 | } | |
1700 | ||
7506f491 | 1701 | hash += (unsigned) code + (unsigned) GET_MODE (x); |
c4c81601 | 1702 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
7506f491 DE |
1703 | { |
1704 | if (fmt[i] == 'e') | |
1705 | { | |
7506f491 DE |
1706 | /* If we are about to do the last recursive call |
1707 | needed at this level, change it into iteration. | |
1708 | This function is called enough to be worth it. */ | |
1709 | if (i == 0) | |
1710 | { | |
c4c81601 | 1711 | x = XEXP (x, i); |
7506f491 DE |
1712 | goto repeat; |
1713 | } | |
c4c81601 RK |
1714 | |
1715 | hash += hash_expr_1 (XEXP (x, i), 0, do_not_record_p); | |
7506f491 DE |
1716 | if (*do_not_record_p) |
1717 | return 0; | |
1718 | } | |
c4c81601 | 1719 | |
7506f491 DE |
1720 | else if (fmt[i] == 'E') |
1721 | for (j = 0; j < XVECLEN (x, i); j++) | |
1722 | { | |
1723 | hash += hash_expr_1 (XVECEXP (x, i, j), 0, do_not_record_p); | |
1724 | if (*do_not_record_p) | |
1725 | return 0; | |
1726 | } | |
c4c81601 | 1727 | |
7506f491 | 1728 | else if (fmt[i] == 's') |
6462bb43 | 1729 | hash += hash_string_1 (XSTR (x, i)); |
7506f491 | 1730 | else if (fmt[i] == 'i') |
c4c81601 | 1731 | hash += (unsigned int) XINT (x, i); |
7506f491 DE |
1732 | else |
1733 | abort (); | |
1734 | } | |
1735 | ||
1736 | return hash; | |
1737 | } | |
1738 | ||
1739 | /* Hash a set of register REGNO. | |
1740 | ||
c4c81601 RK |
1741 | Sets are hashed on the register that is set. This simplifies the PRE copy |
1742 | propagation code. | |
7506f491 DE |
1743 | |
1744 | ??? May need to make things more elaborate. Later, as necessary. */ | |
1745 | ||
1746 | static unsigned int | |
1d088dee | 1747 | hash_set (int regno, int hash_table_size) |
7506f491 DE |
1748 | { |
1749 | unsigned int hash; | |
1750 | ||
1751 | hash = regno; | |
1752 | return hash % hash_table_size; | |
1753 | } | |
1754 | ||
cc2902df | 1755 | /* Return nonzero if exp1 is equivalent to exp2. |
7506f491 DE |
1756 | ??? Borrowed from cse.c. Might want to remerge with cse.c. Later. */ |
1757 | ||
1758 | static int | |
1d088dee | 1759 | expr_equiv_p (rtx x, rtx y) |
7506f491 | 1760 | { |
b3694847 SS |
1761 | int i, j; |
1762 | enum rtx_code code; | |
1763 | const char *fmt; | |
7506f491 DE |
1764 | |
1765 | if (x == y) | |
1766 | return 1; | |
c4c81601 | 1767 | |
7506f491 | 1768 | if (x == 0 || y == 0) |
ebd7a7af | 1769 | return 0; |
7506f491 DE |
1770 | |
1771 | code = GET_CODE (x); | |
1772 | if (code != GET_CODE (y)) | |
1773 | return 0; | |
1774 | ||
1775 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */ | |
1776 | if (GET_MODE (x) != GET_MODE (y)) | |
1777 | return 0; | |
1778 | ||
1779 | switch (code) | |
1780 | { | |
1781 | case PC: | |
1782 | case CC0: | |
7506f491 | 1783 | case CONST_INT: |
ebd7a7af | 1784 | return 0; |
7506f491 DE |
1785 | |
1786 | case LABEL_REF: | |
1787 | return XEXP (x, 0) == XEXP (y, 0); | |
1788 | ||
1789 | case SYMBOL_REF: | |
1790 | return XSTR (x, 0) == XSTR (y, 0); | |
1791 | ||
1792 | case REG: | |
1793 | return REGNO (x) == REGNO (y); | |
1794 | ||
297c3335 RH |
1795 | case MEM: |
1796 | /* Can't merge two expressions in different alias sets, since we can | |
1797 | decide that the expression is transparent in a block when it isn't, | |
1798 | due to it being set with the different alias set. */ | |
1799 | if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y)) | |
1800 | return 0; | |
1801 | break; | |
1802 | ||
7506f491 DE |
1803 | /* For commutative operations, check both orders. */ |
1804 | case PLUS: | |
1805 | case MULT: | |
1806 | case AND: | |
1807 | case IOR: | |
1808 | case XOR: | |
1809 | case NE: | |
1810 | case EQ: | |
1811 | return ((expr_equiv_p (XEXP (x, 0), XEXP (y, 0)) | |
1812 | && expr_equiv_p (XEXP (x, 1), XEXP (y, 1))) | |
1813 | || (expr_equiv_p (XEXP (x, 0), XEXP (y, 1)) | |
1814 | && expr_equiv_p (XEXP (x, 1), XEXP (y, 0)))); | |
1815 | ||
6462bb43 AO |
1816 | case ASM_OPERANDS: |
1817 | /* We don't use the generic code below because we want to | |
1818 | disregard filename and line numbers. */ | |
1819 | ||
1820 | /* A volatile asm isn't equivalent to any other. */ | |
1821 | if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y)) | |
1822 | return 0; | |
1823 | ||
1824 | if (GET_MODE (x) != GET_MODE (y) | |
1825 | || strcmp (ASM_OPERANDS_TEMPLATE (x), ASM_OPERANDS_TEMPLATE (y)) | |
1826 | || strcmp (ASM_OPERANDS_OUTPUT_CONSTRAINT (x), | |
1827 | ASM_OPERANDS_OUTPUT_CONSTRAINT (y)) | |
1828 | || ASM_OPERANDS_OUTPUT_IDX (x) != ASM_OPERANDS_OUTPUT_IDX (y) | |
1829 | || ASM_OPERANDS_INPUT_LENGTH (x) != ASM_OPERANDS_INPUT_LENGTH (y)) | |
1830 | return 0; | |
1831 | ||
1832 | if (ASM_OPERANDS_INPUT_LENGTH (x)) | |
1833 | { | |
1834 | for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--) | |
1835 | if (! expr_equiv_p (ASM_OPERANDS_INPUT (x, i), | |
1836 | ASM_OPERANDS_INPUT (y, i)) | |
1837 | || strcmp (ASM_OPERANDS_INPUT_CONSTRAINT (x, i), | |
1838 | ASM_OPERANDS_INPUT_CONSTRAINT (y, i))) | |
1839 | return 0; | |
1840 | } | |
1841 | ||
1842 | return 1; | |
1843 | ||
7506f491 DE |
1844 | default: |
1845 | break; | |
1846 | } | |
1847 | ||
1848 | /* Compare the elements. If any pair of corresponding elements | |
1849 | fail to match, return 0 for the whole thing. */ | |
1850 | ||
1851 | fmt = GET_RTX_FORMAT (code); | |
1852 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1853 | { | |
1854 | switch (fmt[i]) | |
1855 | { | |
1856 | case 'e': | |
1857 | if (! expr_equiv_p (XEXP (x, i), XEXP (y, i))) | |
1858 | return 0; | |
1859 | break; | |
1860 | ||
1861 | case 'E': | |
1862 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1863 | return 0; | |
1864 | for (j = 0; j < XVECLEN (x, i); j++) | |
1865 | if (! expr_equiv_p (XVECEXP (x, i, j), XVECEXP (y, i, j))) | |
1866 | return 0; | |
1867 | break; | |
1868 | ||
1869 | case 's': | |
1870 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1871 | return 0; | |
1872 | break; | |
1873 | ||
1874 | case 'i': | |
1875 | if (XINT (x, i) != XINT (y, i)) | |
1876 | return 0; | |
1877 | break; | |
1878 | ||
1879 | case 'w': | |
1880 | if (XWINT (x, i) != XWINT (y, i)) | |
1881 | return 0; | |
1882 | break; | |
1883 | ||
1884 | case '0': | |
1885 | break; | |
aaa4ca30 | 1886 | |
7506f491 DE |
1887 | default: |
1888 | abort (); | |
1889 | } | |
8e42ace1 | 1890 | } |
7506f491 DE |
1891 | |
1892 | return 1; | |
1893 | } | |
1894 | ||
02280659 | 1895 | /* Insert expression X in INSN in the hash TABLE. |
7506f491 DE |
1896 | If it is already present, record it as the last occurrence in INSN's |
1897 | basic block. | |
1898 | ||
1899 | MODE is the mode of the value X is being stored into. | |
1900 | It is only used if X is a CONST_INT. | |
1901 | ||
cc2902df KH |
1902 | ANTIC_P is nonzero if X is an anticipatable expression. |
1903 | AVAIL_P is nonzero if X is an available expression. */ | |
7506f491 DE |
1904 | |
1905 | static void | |
1d088dee AJ |
1906 | insert_expr_in_table (rtx x, enum machine_mode mode, rtx insn, int antic_p, |
1907 | int avail_p, struct hash_table *table) | |
7506f491 DE |
1908 | { |
1909 | int found, do_not_record_p; | |
1910 | unsigned int hash; | |
1911 | struct expr *cur_expr, *last_expr = NULL; | |
1912 | struct occr *antic_occr, *avail_occr; | |
1913 | struct occr *last_occr = NULL; | |
1914 | ||
02280659 | 1915 | hash = hash_expr (x, mode, &do_not_record_p, table->size); |
7506f491 DE |
1916 | |
1917 | /* Do not insert expression in table if it contains volatile operands, | |
1918 | or if hash_expr determines the expression is something we don't want | |
1919 | to or can't handle. */ | |
1920 | if (do_not_record_p) | |
1921 | return; | |
1922 | ||
02280659 | 1923 | cur_expr = table->table[hash]; |
7506f491 DE |
1924 | found = 0; |
1925 | ||
c4c81601 | 1926 | while (cur_expr && 0 == (found = expr_equiv_p (cur_expr->expr, x))) |
7506f491 DE |
1927 | { |
1928 | /* If the expression isn't found, save a pointer to the end of | |
1929 | the list. */ | |
1930 | last_expr = cur_expr; | |
1931 | cur_expr = cur_expr->next_same_hash; | |
1932 | } | |
1933 | ||
1934 | if (! found) | |
1935 | { | |
703ad42b | 1936 | cur_expr = gcse_alloc (sizeof (struct expr)); |
7506f491 | 1937 | bytes_used += sizeof (struct expr); |
02280659 | 1938 | if (table->table[hash] == NULL) |
c4c81601 | 1939 | /* This is the first pattern that hashed to this index. */ |
02280659 | 1940 | table->table[hash] = cur_expr; |
7506f491 | 1941 | else |
c4c81601 RK |
1942 | /* Add EXPR to end of this hash chain. */ |
1943 | last_expr->next_same_hash = cur_expr; | |
1944 | ||
589005ff | 1945 | /* Set the fields of the expr element. */ |
7506f491 | 1946 | cur_expr->expr = x; |
02280659 | 1947 | cur_expr->bitmap_index = table->n_elems++; |
7506f491 DE |
1948 | cur_expr->next_same_hash = NULL; |
1949 | cur_expr->antic_occr = NULL; | |
1950 | cur_expr->avail_occr = NULL; | |
1951 | } | |
1952 | ||
1953 | /* Now record the occurrence(s). */ | |
7506f491 DE |
1954 | if (antic_p) |
1955 | { | |
1956 | antic_occr = cur_expr->antic_occr; | |
1957 | ||
1958 | /* Search for another occurrence in the same basic block. */ | |
1959 | while (antic_occr && BLOCK_NUM (antic_occr->insn) != BLOCK_NUM (insn)) | |
1960 | { | |
1961 | /* If an occurrence isn't found, save a pointer to the end of | |
1962 | the list. */ | |
1963 | last_occr = antic_occr; | |
1964 | antic_occr = antic_occr->next; | |
1965 | } | |
1966 | ||
1967 | if (antic_occr) | |
c4c81601 RK |
1968 | /* Found another instance of the expression in the same basic block. |
1969 | Prefer the currently recorded one. We want the first one in the | |
1970 | block and the block is scanned from start to end. */ | |
1971 | ; /* nothing to do */ | |
7506f491 DE |
1972 | else |
1973 | { | |
1974 | /* First occurrence of this expression in this basic block. */ | |
703ad42b | 1975 | antic_occr = gcse_alloc (sizeof (struct occr)); |
7506f491 DE |
1976 | bytes_used += sizeof (struct occr); |
1977 | /* First occurrence of this expression in any block? */ | |
1978 | if (cur_expr->antic_occr == NULL) | |
1979 | cur_expr->antic_occr = antic_occr; | |
1980 | else | |
1981 | last_occr->next = antic_occr; | |
c4c81601 | 1982 | |
7506f491 DE |
1983 | antic_occr->insn = insn; |
1984 | antic_occr->next = NULL; | |
1985 | } | |
1986 | } | |
1987 | ||
1988 | if (avail_p) | |
1989 | { | |
1990 | avail_occr = cur_expr->avail_occr; | |
1991 | ||
1992 | /* Search for another occurrence in the same basic block. */ | |
1993 | while (avail_occr && BLOCK_NUM (avail_occr->insn) != BLOCK_NUM (insn)) | |
1994 | { | |
1995 | /* If an occurrence isn't found, save a pointer to the end of | |
1996 | the list. */ | |
1997 | last_occr = avail_occr; | |
1998 | avail_occr = avail_occr->next; | |
1999 | } | |
2000 | ||
2001 | if (avail_occr) | |
c4c81601 RK |
2002 | /* Found another instance of the expression in the same basic block. |
2003 | Prefer this occurrence to the currently recorded one. We want | |
2004 | the last one in the block and the block is scanned from start | |
2005 | to end. */ | |
2006 | avail_occr->insn = insn; | |
7506f491 DE |
2007 | else |
2008 | { | |
2009 | /* First occurrence of this expression in this basic block. */ | |
703ad42b | 2010 | avail_occr = gcse_alloc (sizeof (struct occr)); |
7506f491 | 2011 | bytes_used += sizeof (struct occr); |
c4c81601 | 2012 | |
7506f491 DE |
2013 | /* First occurrence of this expression in any block? */ |
2014 | if (cur_expr->avail_occr == NULL) | |
2015 | cur_expr->avail_occr = avail_occr; | |
2016 | else | |
2017 | last_occr->next = avail_occr; | |
c4c81601 | 2018 | |
7506f491 DE |
2019 | avail_occr->insn = insn; |
2020 | avail_occr->next = NULL; | |
2021 | } | |
2022 | } | |
2023 | } | |
2024 | ||
2025 | /* Insert pattern X in INSN in the hash table. | |
2026 | X is a SET of a reg to either another reg or a constant. | |
2027 | If it is already present, record it as the last occurrence in INSN's | |
2028 | basic block. */ | |
2029 | ||
2030 | static void | |
1d088dee | 2031 | insert_set_in_table (rtx x, rtx insn, struct hash_table *table) |
7506f491 DE |
2032 | { |
2033 | int found; | |
2034 | unsigned int hash; | |
2035 | struct expr *cur_expr, *last_expr = NULL; | |
2036 | struct occr *cur_occr, *last_occr = NULL; | |
2037 | ||
2038 | if (GET_CODE (x) != SET | |
2039 | || GET_CODE (SET_DEST (x)) != REG) | |
2040 | abort (); | |
2041 | ||
02280659 | 2042 | hash = hash_set (REGNO (SET_DEST (x)), table->size); |
7506f491 | 2043 | |
02280659 | 2044 | cur_expr = table->table[hash]; |
7506f491 DE |
2045 | found = 0; |
2046 | ||
c4c81601 | 2047 | while (cur_expr && 0 == (found = expr_equiv_p (cur_expr->expr, x))) |
7506f491 DE |
2048 | { |
2049 | /* If the expression isn't found, save a pointer to the end of | |
2050 | the list. */ | |
2051 | last_expr = cur_expr; | |
2052 | cur_expr = cur_expr->next_same_hash; | |
2053 | } | |
2054 | ||
2055 | if (! found) | |
2056 | { | |
703ad42b | 2057 | cur_expr = gcse_alloc (sizeof (struct expr)); |
7506f491 | 2058 | bytes_used += sizeof (struct expr); |
02280659 | 2059 | if (table->table[hash] == NULL) |
c4c81601 | 2060 | /* This is the first pattern that hashed to this index. */ |
02280659 | 2061 | table->table[hash] = cur_expr; |
7506f491 | 2062 | else |
c4c81601 RK |
2063 | /* Add EXPR to end of this hash chain. */ |
2064 | last_expr->next_same_hash = cur_expr; | |
2065 | ||
7506f491 DE |
2066 | /* Set the fields of the expr element. |
2067 | We must copy X because it can be modified when copy propagation is | |
2068 | performed on its operands. */ | |
7506f491 | 2069 | cur_expr->expr = copy_rtx (x); |
02280659 | 2070 | cur_expr->bitmap_index = table->n_elems++; |
7506f491 DE |
2071 | cur_expr->next_same_hash = NULL; |
2072 | cur_expr->antic_occr = NULL; | |
2073 | cur_expr->avail_occr = NULL; | |
2074 | } | |
2075 | ||
2076 | /* Now record the occurrence. */ | |
7506f491 DE |
2077 | cur_occr = cur_expr->avail_occr; |
2078 | ||
2079 | /* Search for another occurrence in the same basic block. */ | |
2080 | while (cur_occr && BLOCK_NUM (cur_occr->insn) != BLOCK_NUM (insn)) | |
2081 | { | |
2082 | /* If an occurrence isn't found, save a pointer to the end of | |
2083 | the list. */ | |
2084 | last_occr = cur_occr; | |
2085 | cur_occr = cur_occr->next; | |
2086 | } | |
2087 | ||
2088 | if (cur_occr) | |
c4c81601 RK |
2089 | /* Found another instance of the expression in the same basic block. |
2090 | Prefer this occurrence to the currently recorded one. We want the | |
2091 | last one in the block and the block is scanned from start to end. */ | |
2092 | cur_occr->insn = insn; | |
7506f491 DE |
2093 | else |
2094 | { | |
2095 | /* First occurrence of this expression in this basic block. */ | |
703ad42b | 2096 | cur_occr = gcse_alloc (sizeof (struct occr)); |
7506f491 | 2097 | bytes_used += sizeof (struct occr); |
c4c81601 | 2098 | |
7506f491 DE |
2099 | /* First occurrence of this expression in any block? */ |
2100 | if (cur_expr->avail_occr == NULL) | |
2101 | cur_expr->avail_occr = cur_occr; | |
2102 | else | |
2103 | last_occr->next = cur_occr; | |
c4c81601 | 2104 | |
7506f491 DE |
2105 | cur_occr->insn = insn; |
2106 | cur_occr->next = NULL; | |
2107 | } | |
2108 | } | |
2109 | ||
6b2d1c9e RS |
2110 | /* Determine whether the rtx X should be treated as a constant for |
2111 | the purposes of GCSE's constant propagation. */ | |
2112 | ||
2113 | static bool | |
1d088dee | 2114 | gcse_constant_p (rtx x) |
6b2d1c9e RS |
2115 | { |
2116 | /* Consider a COMPARE of two integers constant. */ | |
2117 | if (GET_CODE (x) == COMPARE | |
2118 | && GET_CODE (XEXP (x, 0)) == CONST_INT | |
2119 | && GET_CODE (XEXP (x, 1)) == CONST_INT) | |
2120 | return true; | |
2121 | ||
db2f435b AP |
2122 | |
2123 | /* Consider a COMPARE of the same registers is a constant | |
2124 | if they are not floating point registers. */ | |
2125 | if (GET_CODE(x) == COMPARE | |
2126 | && GET_CODE (XEXP (x, 0)) == REG | |
2127 | && GET_CODE (XEXP (x, 1)) == REG | |
2128 | && REGNO (XEXP (x, 0)) == REGNO (XEXP (x, 1)) | |
2129 | && ! FLOAT_MODE_P (GET_MODE (XEXP (x, 0))) | |
2130 | && ! FLOAT_MODE_P (GET_MODE (XEXP (x, 1)))) | |
2131 | return true; | |
2132 | ||
6b2d1c9e RS |
2133 | if (GET_CODE (x) == CONSTANT_P_RTX) |
2134 | return false; | |
2135 | ||
2136 | return CONSTANT_P (x); | |
2137 | } | |
2138 | ||
02280659 ZD |
2139 | /* Scan pattern PAT of INSN and add an entry to the hash TABLE (set or |
2140 | expression one). */ | |
7506f491 DE |
2141 | |
2142 | static void | |
1d088dee | 2143 | hash_scan_set (rtx pat, rtx insn, struct hash_table *table) |
7506f491 DE |
2144 | { |
2145 | rtx src = SET_SRC (pat); | |
2146 | rtx dest = SET_DEST (pat); | |
172890a2 | 2147 | rtx note; |
7506f491 DE |
2148 | |
2149 | if (GET_CODE (src) == CALL) | |
02280659 | 2150 | hash_scan_call (src, insn, table); |
7506f491 | 2151 | |
172890a2 | 2152 | else if (GET_CODE (dest) == REG) |
7506f491 | 2153 | { |
172890a2 | 2154 | unsigned int regno = REGNO (dest); |
7506f491 DE |
2155 | rtx tmp; |
2156 | ||
172890a2 RK |
2157 | /* If this is a single set and we are doing constant propagation, |
2158 | see if a REG_NOTE shows this equivalent to a constant. */ | |
02280659 | 2159 | if (table->set_p && (note = find_reg_equal_equiv_note (insn)) != 0 |
6b2d1c9e | 2160 | && gcse_constant_p (XEXP (note, 0))) |
172890a2 RK |
2161 | src = XEXP (note, 0), pat = gen_rtx_SET (VOIDmode, dest, src); |
2162 | ||
7506f491 | 2163 | /* Only record sets of pseudo-regs in the hash table. */ |
02280659 | 2164 | if (! table->set_p |
7506f491 DE |
2165 | && regno >= FIRST_PSEUDO_REGISTER |
2166 | /* Don't GCSE something if we can't do a reg/reg copy. */ | |
773eae39 | 2167 | && can_copy_p (GET_MODE (dest)) |
068473ec JH |
2168 | /* GCSE commonly inserts instruction after the insn. We can't |
2169 | do that easily for EH_REGION notes so disable GCSE on these | |
2170 | for now. */ | |
2171 | && !find_reg_note (insn, REG_EH_REGION, NULL_RTX) | |
7506f491 | 2172 | /* Is SET_SRC something we want to gcse? */ |
172890a2 RK |
2173 | && want_to_gcse_p (src) |
2174 | /* Don't CSE a nop. */ | |
43e72072 JJ |
2175 | && ! set_noop_p (pat) |
2176 | /* Don't GCSE if it has attached REG_EQUIV note. | |
2177 | At this point this only function parameters should have | |
2178 | REG_EQUIV notes and if the argument slot is used somewhere | |
a1f300c0 | 2179 | explicitly, it means address of parameter has been taken, |
43e72072 JJ |
2180 | so we should not extend the lifetime of the pseudo. */ |
2181 | && ((note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) == 0 | |
2182 | || GET_CODE (XEXP (note, 0)) != MEM)) | |
7506f491 DE |
2183 | { |
2184 | /* An expression is not anticipatable if its operands are | |
52d76e11 RK |
2185 | modified before this insn or if this is not the only SET in |
2186 | this insn. */ | |
2187 | int antic_p = oprs_anticipatable_p (src, insn) && single_set (insn); | |
7506f491 | 2188 | /* An expression is not available if its operands are |
eb296bd9 GK |
2189 | subsequently modified, including this insn. It's also not |
2190 | available if this is a branch, because we can't insert | |
2191 | a set after the branch. */ | |
2192 | int avail_p = (oprs_available_p (src, insn) | |
2193 | && ! JUMP_P (insn)); | |
c4c81601 | 2194 | |
02280659 | 2195 | insert_expr_in_table (src, GET_MODE (dest), insn, antic_p, avail_p, table); |
7506f491 | 2196 | } |
c4c81601 | 2197 | |
7506f491 | 2198 | /* Record sets for constant/copy propagation. */ |
02280659 | 2199 | else if (table->set_p |
7506f491 DE |
2200 | && regno >= FIRST_PSEUDO_REGISTER |
2201 | && ((GET_CODE (src) == REG | |
2202 | && REGNO (src) >= FIRST_PSEUDO_REGISTER | |
773eae39 | 2203 | && can_copy_p (GET_MODE (dest)) |
172890a2 | 2204 | && REGNO (src) != regno) |
6b2d1c9e | 2205 | || gcse_constant_p (src)) |
7506f491 DE |
2206 | /* A copy is not available if its src or dest is subsequently |
2207 | modified. Here we want to search from INSN+1 on, but | |
2208 | oprs_available_p searches from INSN on. */ | |
2209 | && (insn == BLOCK_END (BLOCK_NUM (insn)) | |
2210 | || ((tmp = next_nonnote_insn (insn)) != NULL_RTX | |
2211 | && oprs_available_p (pat, tmp)))) | |
02280659 | 2212 | insert_set_in_table (pat, insn, table); |
7506f491 | 2213 | } |
7506f491 DE |
2214 | } |
2215 | ||
2216 | static void | |
1d088dee AJ |
2217 | hash_scan_clobber (rtx x ATTRIBUTE_UNUSED, rtx insn ATTRIBUTE_UNUSED, |
2218 | struct hash_table *table ATTRIBUTE_UNUSED) | |
7506f491 DE |
2219 | { |
2220 | /* Currently nothing to do. */ | |
2221 | } | |
2222 | ||
2223 | static void | |
1d088dee AJ |
2224 | hash_scan_call (rtx x ATTRIBUTE_UNUSED, rtx insn ATTRIBUTE_UNUSED, |
2225 | struct hash_table *table ATTRIBUTE_UNUSED) | |
7506f491 DE |
2226 | { |
2227 | /* Currently nothing to do. */ | |
2228 | } | |
2229 | ||
2230 | /* Process INSN and add hash table entries as appropriate. | |
2231 | ||
2232 | Only available expressions that set a single pseudo-reg are recorded. | |
2233 | ||
2234 | Single sets in a PARALLEL could be handled, but it's an extra complication | |
2235 | that isn't dealt with right now. The trick is handling the CLOBBERs that | |
2236 | are also in the PARALLEL. Later. | |
2237 | ||
cc2902df | 2238 | If SET_P is nonzero, this is for the assignment hash table, |
ed79bb3d R |
2239 | otherwise it is for the expression hash table. |
2240 | If IN_LIBCALL_BLOCK nonzero, we are in a libcall block, and should | |
2241 | not record any expressions. */ | |
7506f491 DE |
2242 | |
2243 | static void | |
1d088dee | 2244 | hash_scan_insn (rtx insn, struct hash_table *table, int in_libcall_block) |
7506f491 DE |
2245 | { |
2246 | rtx pat = PATTERN (insn); | |
c4c81601 | 2247 | int i; |
7506f491 | 2248 | |
172890a2 RK |
2249 | if (in_libcall_block) |
2250 | return; | |
2251 | ||
7506f491 DE |
2252 | /* Pick out the sets of INSN and for other forms of instructions record |
2253 | what's been modified. */ | |
2254 | ||
172890a2 | 2255 | if (GET_CODE (pat) == SET) |
02280659 | 2256 | hash_scan_set (pat, insn, table); |
7506f491 | 2257 | else if (GET_CODE (pat) == PARALLEL) |
c4c81601 RK |
2258 | for (i = 0; i < XVECLEN (pat, 0); i++) |
2259 | { | |
2260 | rtx x = XVECEXP (pat, 0, i); | |
7506f491 | 2261 | |
c4c81601 | 2262 | if (GET_CODE (x) == SET) |
02280659 | 2263 | hash_scan_set (x, insn, table); |
c4c81601 | 2264 | else if (GET_CODE (x) == CLOBBER) |
02280659 | 2265 | hash_scan_clobber (x, insn, table); |
c4c81601 | 2266 | else if (GET_CODE (x) == CALL) |
02280659 | 2267 | hash_scan_call (x, insn, table); |
c4c81601 | 2268 | } |
7506f491 | 2269 | |
7506f491 | 2270 | else if (GET_CODE (pat) == CLOBBER) |
02280659 | 2271 | hash_scan_clobber (pat, insn, table); |
7506f491 | 2272 | else if (GET_CODE (pat) == CALL) |
02280659 | 2273 | hash_scan_call (pat, insn, table); |
7506f491 DE |
2274 | } |
2275 | ||
2276 | static void | |
1d088dee | 2277 | dump_hash_table (FILE *file, const char *name, struct hash_table *table) |
7506f491 DE |
2278 | { |
2279 | int i; | |
2280 | /* Flattened out table, so it's printed in proper order. */ | |
4da896b2 MM |
2281 | struct expr **flat_table; |
2282 | unsigned int *hash_val; | |
c4c81601 | 2283 | struct expr *expr; |
4da896b2 | 2284 | |
703ad42b KG |
2285 | flat_table = xcalloc (table->n_elems, sizeof (struct expr *)); |
2286 | hash_val = xmalloc (table->n_elems * sizeof (unsigned int)); | |
7506f491 | 2287 | |
02280659 ZD |
2288 | for (i = 0; i < (int) table->size; i++) |
2289 | for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash) | |
c4c81601 RK |
2290 | { |
2291 | flat_table[expr->bitmap_index] = expr; | |
2292 | hash_val[expr->bitmap_index] = i; | |
2293 | } | |
7506f491 DE |
2294 | |
2295 | fprintf (file, "%s hash table (%d buckets, %d entries)\n", | |
02280659 | 2296 | name, table->size, table->n_elems); |
7506f491 | 2297 | |
02280659 | 2298 | for (i = 0; i < (int) table->n_elems; i++) |
21318741 RK |
2299 | if (flat_table[i] != 0) |
2300 | { | |
a0ac9e5a | 2301 | expr = flat_table[i]; |
21318741 RK |
2302 | fprintf (file, "Index %d (hash value %d)\n ", |
2303 | expr->bitmap_index, hash_val[i]); | |
a0ac9e5a | 2304 | print_rtl (file, expr->expr); |
21318741 RK |
2305 | fprintf (file, "\n"); |
2306 | } | |
7506f491 DE |
2307 | |
2308 | fprintf (file, "\n"); | |
4da896b2 | 2309 | |
4da896b2 MM |
2310 | free (flat_table); |
2311 | free (hash_val); | |
7506f491 DE |
2312 | } |
2313 | ||
2314 | /* Record register first/last/block set information for REGNO in INSN. | |
c4c81601 | 2315 | |
80c29cc4 | 2316 | first_set records the first place in the block where the register |
7506f491 | 2317 | is set and is used to compute "anticipatability". |
c4c81601 | 2318 | |
80c29cc4 | 2319 | last_set records the last place in the block where the register |
7506f491 | 2320 | is set and is used to compute "availability". |
c4c81601 | 2321 | |
80c29cc4 RZ |
2322 | last_bb records the block for which first_set and last_set are |
2323 | valid, as a quick test to invalidate them. | |
2324 | ||
7506f491 DE |
2325 | reg_set_in_block records whether the register is set in the block |
2326 | and is used to compute "transparency". */ | |
2327 | ||
2328 | static void | |
1d088dee | 2329 | record_last_reg_set_info (rtx insn, int regno) |
7506f491 | 2330 | { |
80c29cc4 RZ |
2331 | struct reg_avail_info *info = ®_avail_info[regno]; |
2332 | int cuid = INSN_CUID (insn); | |
c4c81601 | 2333 | |
80c29cc4 RZ |
2334 | info->last_set = cuid; |
2335 | if (info->last_bb != current_bb) | |
2336 | { | |
2337 | info->last_bb = current_bb; | |
2338 | info->first_set = cuid; | |
e0082a72 | 2339 | SET_BIT (reg_set_in_block[current_bb->index], regno); |
80c29cc4 | 2340 | } |
7506f491 DE |
2341 | } |
2342 | ||
a13d4ebf AM |
2343 | |
2344 | /* Record all of the canonicalized MEMs of record_last_mem_set_info's insn. | |
2345 | Note we store a pair of elements in the list, so they have to be | |
2346 | taken off pairwise. */ | |
2347 | ||
589005ff | 2348 | static void |
1d088dee AJ |
2349 | canon_list_insert (rtx dest ATTRIBUTE_UNUSED, rtx unused1 ATTRIBUTE_UNUSED, |
2350 | void * v_insn) | |
a13d4ebf AM |
2351 | { |
2352 | rtx dest_addr, insn; | |
0fe854a7 | 2353 | int bb; |
a13d4ebf AM |
2354 | |
2355 | while (GET_CODE (dest) == SUBREG | |
2356 | || GET_CODE (dest) == ZERO_EXTRACT | |
2357 | || GET_CODE (dest) == SIGN_EXTRACT | |
2358 | || GET_CODE (dest) == STRICT_LOW_PART) | |
2359 | dest = XEXP (dest, 0); | |
2360 | ||
2361 | /* If DEST is not a MEM, then it will not conflict with a load. Note | |
2362 | that function calls are assumed to clobber memory, but are handled | |
2363 | elsewhere. */ | |
2364 | ||
2365 | if (GET_CODE (dest) != MEM) | |
2366 | return; | |
2367 | ||
2368 | dest_addr = get_addr (XEXP (dest, 0)); | |
2369 | dest_addr = canon_rtx (dest_addr); | |
589005ff | 2370 | insn = (rtx) v_insn; |
0fe854a7 | 2371 | bb = BLOCK_NUM (insn); |
a13d4ebf | 2372 | |
589005ff | 2373 | canon_modify_mem_list[bb] = |
0fe854a7 | 2374 | alloc_EXPR_LIST (VOIDmode, dest_addr, canon_modify_mem_list[bb]); |
589005ff | 2375 | canon_modify_mem_list[bb] = |
0fe854a7 RH |
2376 | alloc_EXPR_LIST (VOIDmode, dest, canon_modify_mem_list[bb]); |
2377 | bitmap_set_bit (canon_modify_mem_list_set, bb); | |
a13d4ebf AM |
2378 | } |
2379 | ||
a13d4ebf AM |
2380 | /* Record memory modification information for INSN. We do not actually care |
2381 | about the memory location(s) that are set, or even how they are set (consider | |
2382 | a CALL_INSN). We merely need to record which insns modify memory. */ | |
7506f491 DE |
2383 | |
2384 | static void | |
1d088dee | 2385 | record_last_mem_set_info (rtx insn) |
7506f491 | 2386 | { |
0fe854a7 RH |
2387 | int bb = BLOCK_NUM (insn); |
2388 | ||
ccef9ef5 | 2389 | /* load_killed_in_block_p will handle the case of calls clobbering |
dc297297 | 2390 | everything. */ |
0fe854a7 RH |
2391 | modify_mem_list[bb] = alloc_INSN_LIST (insn, modify_mem_list[bb]); |
2392 | bitmap_set_bit (modify_mem_list_set, bb); | |
a13d4ebf AM |
2393 | |
2394 | if (GET_CODE (insn) == CALL_INSN) | |
2395 | { | |
2396 | /* Note that traversals of this loop (other than for free-ing) | |
2397 | will break after encountering a CALL_INSN. So, there's no | |
dc297297 | 2398 | need to insert a pair of items, as canon_list_insert does. */ |
589005ff KH |
2399 | canon_modify_mem_list[bb] = |
2400 | alloc_INSN_LIST (insn, canon_modify_mem_list[bb]); | |
0fe854a7 | 2401 | bitmap_set_bit (canon_modify_mem_list_set, bb); |
a13d4ebf AM |
2402 | } |
2403 | else | |
0fe854a7 | 2404 | note_stores (PATTERN (insn), canon_list_insert, (void*) insn); |
7506f491 DE |
2405 | } |
2406 | ||
7506f491 | 2407 | /* Called from compute_hash_table via note_stores to handle one |
84832317 MM |
2408 | SET or CLOBBER in an insn. DATA is really the instruction in which |
2409 | the SET is taking place. */ | |
7506f491 DE |
2410 | |
2411 | static void | |
1d088dee | 2412 | record_last_set_info (rtx dest, rtx setter ATTRIBUTE_UNUSED, void *data) |
7506f491 | 2413 | { |
84832317 MM |
2414 | rtx last_set_insn = (rtx) data; |
2415 | ||
7506f491 DE |
2416 | if (GET_CODE (dest) == SUBREG) |
2417 | dest = SUBREG_REG (dest); | |
2418 | ||
2419 | if (GET_CODE (dest) == REG) | |
2420 | record_last_reg_set_info (last_set_insn, REGNO (dest)); | |
2421 | else if (GET_CODE (dest) == MEM | |
2422 | /* Ignore pushes, they clobber nothing. */ | |
2423 | && ! push_operand (dest, GET_MODE (dest))) | |
2424 | record_last_mem_set_info (last_set_insn); | |
2425 | } | |
2426 | ||
2427 | /* Top level function to create an expression or assignment hash table. | |
2428 | ||
2429 | Expression entries are placed in the hash table if | |
2430 | - they are of the form (set (pseudo-reg) src), | |
2431 | - src is something we want to perform GCSE on, | |
2432 | - none of the operands are subsequently modified in the block | |
2433 | ||
2434 | Assignment entries are placed in the hash table if | |
2435 | - they are of the form (set (pseudo-reg) src), | |
2436 | - src is something we want to perform const/copy propagation on, | |
2437 | - none of the operands or target are subsequently modified in the block | |
c4c81601 | 2438 | |
7506f491 DE |
2439 | Currently src must be a pseudo-reg or a const_int. |
2440 | ||
02280659 | 2441 | TABLE is the table computed. */ |
7506f491 DE |
2442 | |
2443 | static void | |
1d088dee | 2444 | compute_hash_table_work (struct hash_table *table) |
7506f491 | 2445 | { |
80c29cc4 | 2446 | unsigned int i; |
7506f491 DE |
2447 | |
2448 | /* While we compute the hash table we also compute a bit array of which | |
2449 | registers are set in which blocks. | |
7506f491 DE |
2450 | ??? This isn't needed during const/copy propagation, but it's cheap to |
2451 | compute. Later. */ | |
d55bc081 | 2452 | sbitmap_vector_zero (reg_set_in_block, last_basic_block); |
7506f491 | 2453 | |
a13d4ebf | 2454 | /* re-Cache any INSN_LIST nodes we have allocated. */ |
73991d6a | 2455 | clear_modify_mem_tables (); |
7506f491 | 2456 | /* Some working arrays used to track first and last set in each block. */ |
703ad42b | 2457 | reg_avail_info = gmalloc (max_gcse_regno * sizeof (struct reg_avail_info)); |
80c29cc4 RZ |
2458 | |
2459 | for (i = 0; i < max_gcse_regno; ++i) | |
e0082a72 | 2460 | reg_avail_info[i].last_bb = NULL; |
7506f491 | 2461 | |
e0082a72 | 2462 | FOR_EACH_BB (current_bb) |
7506f491 DE |
2463 | { |
2464 | rtx insn; | |
770ae6cc | 2465 | unsigned int regno; |
ed79bb3d | 2466 | int in_libcall_block; |
7506f491 DE |
2467 | |
2468 | /* First pass over the instructions records information used to | |
2469 | determine when registers and memory are first and last set. | |
ccef9ef5 | 2470 | ??? hard-reg reg_set_in_block computation |
7506f491 DE |
2471 | could be moved to compute_sets since they currently don't change. */ |
2472 | ||
e0082a72 ZD |
2473 | for (insn = current_bb->head; |
2474 | insn && insn != NEXT_INSN (current_bb->end); | |
7506f491 DE |
2475 | insn = NEXT_INSN (insn)) |
2476 | { | |
2c3c49de | 2477 | if (! INSN_P (insn)) |
7506f491 DE |
2478 | continue; |
2479 | ||
2480 | if (GET_CODE (insn) == CALL_INSN) | |
2481 | { | |
19652adf | 2482 | bool clobbers_all = false; |
589005ff | 2483 | #ifdef NON_SAVING_SETJMP |
19652adf ZW |
2484 | if (NON_SAVING_SETJMP |
2485 | && find_reg_note (insn, REG_SETJMP, NULL_RTX)) | |
2486 | clobbers_all = true; | |
2487 | #endif | |
2488 | ||
7506f491 | 2489 | for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) |
19652adf ZW |
2490 | if (clobbers_all |
2491 | || TEST_HARD_REG_BIT (regs_invalidated_by_call, regno)) | |
7506f491 | 2492 | record_last_reg_set_info (insn, regno); |
c4c81601 | 2493 | |
24a28584 | 2494 | mark_call (insn); |
7506f491 DE |
2495 | } |
2496 | ||
84832317 | 2497 | note_stores (PATTERN (insn), record_last_set_info, insn); |
7506f491 DE |
2498 | } |
2499 | ||
fbef91d8 RS |
2500 | /* Insert implicit sets in the hash table. */ |
2501 | if (table->set_p | |
2502 | && implicit_sets[current_bb->index] != NULL_RTX) | |
2503 | hash_scan_set (implicit_sets[current_bb->index], | |
2504 | current_bb->head, table); | |
2505 | ||
7506f491 DE |
2506 | /* The next pass builds the hash table. */ |
2507 | ||
e0082a72 ZD |
2508 | for (insn = current_bb->head, in_libcall_block = 0; |
2509 | insn && insn != NEXT_INSN (current_bb->end); | |
7506f491 | 2510 | insn = NEXT_INSN (insn)) |
2c3c49de | 2511 | if (INSN_P (insn)) |
c4c81601 RK |
2512 | { |
2513 | if (find_reg_note (insn, REG_LIBCALL, NULL_RTX)) | |
589005ff | 2514 | in_libcall_block = 1; |
02280659 | 2515 | else if (table->set_p && find_reg_note (insn, REG_RETVAL, NULL_RTX)) |
589005ff | 2516 | in_libcall_block = 0; |
02280659 ZD |
2517 | hash_scan_insn (insn, table, in_libcall_block); |
2518 | if (!table->set_p && find_reg_note (insn, REG_RETVAL, NULL_RTX)) | |
589005ff | 2519 | in_libcall_block = 0; |
8e42ace1 | 2520 | } |
7506f491 DE |
2521 | } |
2522 | ||
80c29cc4 RZ |
2523 | free (reg_avail_info); |
2524 | reg_avail_info = NULL; | |
7506f491 DE |
2525 | } |
2526 | ||
02280659 | 2527 | /* Allocate space for the set/expr hash TABLE. |
7506f491 | 2528 | N_INSNS is the number of instructions in the function. |
02280659 ZD |
2529 | It is used to determine the number of buckets to use. |
2530 | SET_P determines whether set or expression table will | |
2531 | be created. */ | |
7506f491 DE |
2532 | |
2533 | static void | |
1d088dee | 2534 | alloc_hash_table (int n_insns, struct hash_table *table, int set_p) |
7506f491 DE |
2535 | { |
2536 | int n; | |
2537 | ||
02280659 ZD |
2538 | table->size = n_insns / 4; |
2539 | if (table->size < 11) | |
2540 | table->size = 11; | |
c4c81601 | 2541 | |
7506f491 DE |
2542 | /* Attempt to maintain efficient use of hash table. |
2543 | Making it an odd number is simplest for now. | |
2544 | ??? Later take some measurements. */ | |
02280659 ZD |
2545 | table->size |= 1; |
2546 | n = table->size * sizeof (struct expr *); | |
703ad42b | 2547 | table->table = gmalloc (n); |
02280659 | 2548 | table->set_p = set_p; |
7506f491 DE |
2549 | } |
2550 | ||
02280659 | 2551 | /* Free things allocated by alloc_hash_table. */ |
7506f491 DE |
2552 | |
2553 | static void | |
1d088dee | 2554 | free_hash_table (struct hash_table *table) |
7506f491 | 2555 | { |
02280659 | 2556 | free (table->table); |
7506f491 DE |
2557 | } |
2558 | ||
02280659 ZD |
2559 | /* Compute the hash TABLE for doing copy/const propagation or |
2560 | expression hash table. */ | |
7506f491 DE |
2561 | |
2562 | static void | |
1d088dee | 2563 | compute_hash_table (struct hash_table *table) |
7506f491 DE |
2564 | { |
2565 | /* Initialize count of number of entries in hash table. */ | |
02280659 | 2566 | table->n_elems = 0; |
703ad42b | 2567 | memset (table->table, 0, table->size * sizeof (struct expr *)); |
7506f491 | 2568 | |
02280659 | 2569 | compute_hash_table_work (table); |
7506f491 DE |
2570 | } |
2571 | \f | |
2572 | /* Expression tracking support. */ | |
2573 | ||
02280659 | 2574 | /* Lookup pattern PAT in the expression TABLE. |
7506f491 DE |
2575 | The result is a pointer to the table entry, or NULL if not found. */ |
2576 | ||
2577 | static struct expr * | |
1d088dee | 2578 | lookup_expr (rtx pat, struct hash_table *table) |
7506f491 DE |
2579 | { |
2580 | int do_not_record_p; | |
2581 | unsigned int hash = hash_expr (pat, GET_MODE (pat), &do_not_record_p, | |
02280659 | 2582 | table->size); |
7506f491 DE |
2583 | struct expr *expr; |
2584 | ||
2585 | if (do_not_record_p) | |
2586 | return NULL; | |
2587 | ||
02280659 | 2588 | expr = table->table[hash]; |
7506f491 DE |
2589 | |
2590 | while (expr && ! expr_equiv_p (expr->expr, pat)) | |
2591 | expr = expr->next_same_hash; | |
2592 | ||
2593 | return expr; | |
2594 | } | |
2595 | ||
ceda50e9 RH |
2596 | /* Lookup REGNO in the set TABLE. The result is a pointer to the |
2597 | table entry, or NULL if not found. */ | |
7506f491 DE |
2598 | |
2599 | static struct expr * | |
1d088dee | 2600 | lookup_set (unsigned int regno, struct hash_table *table) |
7506f491 | 2601 | { |
02280659 | 2602 | unsigned int hash = hash_set (regno, table->size); |
7506f491 DE |
2603 | struct expr *expr; |
2604 | ||
02280659 | 2605 | expr = table->table[hash]; |
7506f491 | 2606 | |
ceda50e9 RH |
2607 | while (expr && REGNO (SET_DEST (expr->expr)) != regno) |
2608 | expr = expr->next_same_hash; | |
7506f491 DE |
2609 | |
2610 | return expr; | |
2611 | } | |
2612 | ||
2613 | /* Return the next entry for REGNO in list EXPR. */ | |
2614 | ||
2615 | static struct expr * | |
1d088dee | 2616 | next_set (unsigned int regno, struct expr *expr) |
7506f491 DE |
2617 | { |
2618 | do | |
2619 | expr = expr->next_same_hash; | |
2620 | while (expr && REGNO (SET_DEST (expr->expr)) != regno); | |
c4c81601 | 2621 | |
7506f491 DE |
2622 | return expr; |
2623 | } | |
2624 | ||
0fe854a7 RH |
2625 | /* Like free_INSN_LIST_list or free_EXPR_LIST_list, except that the node |
2626 | types may be mixed. */ | |
2627 | ||
2628 | static void | |
1d088dee | 2629 | free_insn_expr_list_list (rtx *listp) |
0fe854a7 RH |
2630 | { |
2631 | rtx list, next; | |
2632 | ||
2633 | for (list = *listp; list ; list = next) | |
2634 | { | |
2635 | next = XEXP (list, 1); | |
2636 | if (GET_CODE (list) == EXPR_LIST) | |
2637 | free_EXPR_LIST_node (list); | |
2638 | else | |
2639 | free_INSN_LIST_node (list); | |
2640 | } | |
2641 | ||
2642 | *listp = NULL; | |
2643 | } | |
2644 | ||
73991d6a JH |
2645 | /* Clear canon_modify_mem_list and modify_mem_list tables. */ |
2646 | static void | |
1d088dee | 2647 | clear_modify_mem_tables (void) |
73991d6a JH |
2648 | { |
2649 | int i; | |
2650 | ||
2651 | EXECUTE_IF_SET_IN_BITMAP | |
0fe854a7 RH |
2652 | (modify_mem_list_set, 0, i, free_INSN_LIST_list (modify_mem_list + i)); |
2653 | bitmap_clear (modify_mem_list_set); | |
73991d6a JH |
2654 | |
2655 | EXECUTE_IF_SET_IN_BITMAP | |
2656 | (canon_modify_mem_list_set, 0, i, | |
0fe854a7 RH |
2657 | free_insn_expr_list_list (canon_modify_mem_list + i)); |
2658 | bitmap_clear (canon_modify_mem_list_set); | |
73991d6a JH |
2659 | } |
2660 | ||
2661 | /* Release memory used by modify_mem_list_set and canon_modify_mem_list_set. */ | |
2662 | ||
2663 | static void | |
1d088dee | 2664 | free_modify_mem_tables (void) |
73991d6a JH |
2665 | { |
2666 | clear_modify_mem_tables (); | |
2667 | free (modify_mem_list); | |
2668 | free (canon_modify_mem_list); | |
2669 | modify_mem_list = 0; | |
2670 | canon_modify_mem_list = 0; | |
2671 | } | |
2672 | ||
7506f491 DE |
2673 | /* Reset tables used to keep track of what's still available [since the |
2674 | start of the block]. */ | |
2675 | ||
2676 | static void | |
1d088dee | 2677 | reset_opr_set_tables (void) |
7506f491 DE |
2678 | { |
2679 | /* Maintain a bitmap of which regs have been set since beginning of | |
2680 | the block. */ | |
73991d6a | 2681 | CLEAR_REG_SET (reg_set_bitmap); |
c4c81601 | 2682 | |
7506f491 DE |
2683 | /* Also keep a record of the last instruction to modify memory. |
2684 | For now this is very trivial, we only record whether any memory | |
2685 | location has been modified. */ | |
73991d6a | 2686 | clear_modify_mem_tables (); |
7506f491 DE |
2687 | } |
2688 | ||
cc2902df | 2689 | /* Return nonzero if the operands of X are not set before INSN in |
7506f491 DE |
2690 | INSN's basic block. */ |
2691 | ||
2692 | static int | |
1d088dee | 2693 | oprs_not_set_p (rtx x, rtx insn) |
7506f491 | 2694 | { |
c4c81601 | 2695 | int i, j; |
7506f491 | 2696 | enum rtx_code code; |
6f7d635c | 2697 | const char *fmt; |
7506f491 | 2698 | |
7506f491 DE |
2699 | if (x == 0) |
2700 | return 1; | |
2701 | ||
2702 | code = GET_CODE (x); | |
2703 | switch (code) | |
2704 | { | |
2705 | case PC: | |
2706 | case CC0: | |
2707 | case CONST: | |
2708 | case CONST_INT: | |
2709 | case CONST_DOUBLE: | |
69ef87e2 | 2710 | case CONST_VECTOR: |
7506f491 DE |
2711 | case SYMBOL_REF: |
2712 | case LABEL_REF: | |
2713 | case ADDR_VEC: | |
2714 | case ADDR_DIFF_VEC: | |
2715 | return 1; | |
2716 | ||
2717 | case MEM: | |
589005ff | 2718 | if (load_killed_in_block_p (BLOCK_FOR_INSN (insn), |
e2d2ed72 | 2719 | INSN_CUID (insn), x, 0)) |
a13d4ebf | 2720 | return 0; |
c4c81601 RK |
2721 | else |
2722 | return oprs_not_set_p (XEXP (x, 0), insn); | |
7506f491 DE |
2723 | |
2724 | case REG: | |
73991d6a | 2725 | return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x)); |
7506f491 DE |
2726 | |
2727 | default: | |
2728 | break; | |
2729 | } | |
2730 | ||
c4c81601 | 2731 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
7506f491 DE |
2732 | { |
2733 | if (fmt[i] == 'e') | |
2734 | { | |
7506f491 DE |
2735 | /* If we are about to do the last recursive call |
2736 | needed at this level, change it into iteration. | |
2737 | This function is called enough to be worth it. */ | |
2738 | if (i == 0) | |
c4c81601 RK |
2739 | return oprs_not_set_p (XEXP (x, i), insn); |
2740 | ||
2741 | if (! oprs_not_set_p (XEXP (x, i), insn)) | |
7506f491 DE |
2742 | return 0; |
2743 | } | |
2744 | else if (fmt[i] == 'E') | |
c4c81601 RK |
2745 | for (j = 0; j < XVECLEN (x, i); j++) |
2746 | if (! oprs_not_set_p (XVECEXP (x, i, j), insn)) | |
2747 | return 0; | |
7506f491 DE |
2748 | } |
2749 | ||
2750 | return 1; | |
2751 | } | |
2752 | ||
2753 | /* Mark things set by a CALL. */ | |
2754 | ||
2755 | static void | |
1d088dee | 2756 | mark_call (rtx insn) |
7506f491 | 2757 | { |
24a28584 | 2758 | if (! CONST_OR_PURE_CALL_P (insn)) |
a13d4ebf | 2759 | record_last_mem_set_info (insn); |
7506f491 DE |
2760 | } |
2761 | ||
2762 | /* Mark things set by a SET. */ | |
2763 | ||
2764 | static void | |
1d088dee | 2765 | mark_set (rtx pat, rtx insn) |
7506f491 DE |
2766 | { |
2767 | rtx dest = SET_DEST (pat); | |
2768 | ||
2769 | while (GET_CODE (dest) == SUBREG | |
2770 | || GET_CODE (dest) == ZERO_EXTRACT | |
2771 | || GET_CODE (dest) == SIGN_EXTRACT | |
2772 | || GET_CODE (dest) == STRICT_LOW_PART) | |
2773 | dest = XEXP (dest, 0); | |
2774 | ||
a13d4ebf | 2775 | if (GET_CODE (dest) == REG) |
73991d6a | 2776 | SET_REGNO_REG_SET (reg_set_bitmap, REGNO (dest)); |
a13d4ebf AM |
2777 | else if (GET_CODE (dest) == MEM) |
2778 | record_last_mem_set_info (insn); | |
2779 | ||
7506f491 | 2780 | if (GET_CODE (SET_SRC (pat)) == CALL) |
b5ce41ff | 2781 | mark_call (insn); |
7506f491 DE |
2782 | } |
2783 | ||
2784 | /* Record things set by a CLOBBER. */ | |
2785 | ||
2786 | static void | |
1d088dee | 2787 | mark_clobber (rtx pat, rtx insn) |
7506f491 DE |
2788 | { |
2789 | rtx clob = XEXP (pat, 0); | |
2790 | ||
2791 | while (GET_CODE (clob) == SUBREG || GET_CODE (clob) == STRICT_LOW_PART) | |
2792 | clob = XEXP (clob, 0); | |
2793 | ||
a13d4ebf | 2794 | if (GET_CODE (clob) == REG) |
73991d6a | 2795 | SET_REGNO_REG_SET (reg_set_bitmap, REGNO (clob)); |
a13d4ebf AM |
2796 | else |
2797 | record_last_mem_set_info (insn); | |
7506f491 DE |
2798 | } |
2799 | ||
2800 | /* Record things set by INSN. | |
2801 | This data is used by oprs_not_set_p. */ | |
2802 | ||
2803 | static void | |
1d088dee | 2804 | mark_oprs_set (rtx insn) |
7506f491 DE |
2805 | { |
2806 | rtx pat = PATTERN (insn); | |
c4c81601 | 2807 | int i; |
7506f491 DE |
2808 | |
2809 | if (GET_CODE (pat) == SET) | |
2810 | mark_set (pat, insn); | |
2811 | else if (GET_CODE (pat) == PARALLEL) | |
c4c81601 RK |
2812 | for (i = 0; i < XVECLEN (pat, 0); i++) |
2813 | { | |
2814 | rtx x = XVECEXP (pat, 0, i); | |
2815 | ||
2816 | if (GET_CODE (x) == SET) | |
2817 | mark_set (x, insn); | |
2818 | else if (GET_CODE (x) == CLOBBER) | |
2819 | mark_clobber (x, insn); | |
2820 | else if (GET_CODE (x) == CALL) | |
2821 | mark_call (insn); | |
2822 | } | |
7506f491 | 2823 | |
7506f491 DE |
2824 | else if (GET_CODE (pat) == CLOBBER) |
2825 | mark_clobber (pat, insn); | |
2826 | else if (GET_CODE (pat) == CALL) | |
b5ce41ff | 2827 | mark_call (insn); |
7506f491 | 2828 | } |
b5ce41ff | 2829 | |
7506f491 DE |
2830 | \f |
2831 | /* Classic GCSE reaching definition support. */ | |
2832 | ||
2833 | /* Allocate reaching def variables. */ | |
2834 | ||
2835 | static void | |
1d088dee | 2836 | alloc_rd_mem (int n_blocks, int n_insns) |
7506f491 | 2837 | { |
703ad42b | 2838 | rd_kill = sbitmap_vector_alloc (n_blocks, n_insns); |
d55bc081 | 2839 | sbitmap_vector_zero (rd_kill, n_blocks); |
7506f491 | 2840 | |
703ad42b | 2841 | rd_gen = sbitmap_vector_alloc (n_blocks, n_insns); |
d55bc081 | 2842 | sbitmap_vector_zero (rd_gen, n_blocks); |
7506f491 | 2843 | |
703ad42b | 2844 | reaching_defs = sbitmap_vector_alloc (n_blocks, n_insns); |
d55bc081 | 2845 | sbitmap_vector_zero (reaching_defs, n_blocks); |
7506f491 | 2846 | |
703ad42b | 2847 | rd_out = sbitmap_vector_alloc (n_blocks, n_insns); |
d55bc081 | 2848 | sbitmap_vector_zero (rd_out, n_blocks); |
7506f491 DE |
2849 | } |
2850 | ||
2851 | /* Free reaching def variables. */ | |
2852 | ||
2853 | static void | |
1d088dee | 2854 | free_rd_mem (void) |
7506f491 | 2855 | { |
5a660bff DB |
2856 | sbitmap_vector_free (rd_kill); |
2857 | sbitmap_vector_free (rd_gen); | |
2858 | sbitmap_vector_free (reaching_defs); | |
2859 | sbitmap_vector_free (rd_out); | |
7506f491 DE |
2860 | } |
2861 | ||
c4c81601 | 2862 | /* Add INSN to the kills of BB. REGNO, set in BB, is killed by INSN. */ |
7506f491 DE |
2863 | |
2864 | static void | |
1d088dee | 2865 | handle_rd_kill_set (rtx insn, int regno, basic_block bb) |
7506f491 | 2866 | { |
c4c81601 | 2867 | struct reg_set *this_reg; |
7506f491 | 2868 | |
c4c81601 RK |
2869 | for (this_reg = reg_set_table[regno]; this_reg; this_reg = this_reg ->next) |
2870 | if (BLOCK_NUM (this_reg->insn) != BLOCK_NUM (insn)) | |
0b17ab2f | 2871 | SET_BIT (rd_kill[bb->index], INSN_CUID (this_reg->insn)); |
7506f491 DE |
2872 | } |
2873 | ||
7506f491 DE |
2874 | /* Compute the set of kill's for reaching definitions. */ |
2875 | ||
2876 | static void | |
1d088dee | 2877 | compute_kill_rd (void) |
7506f491 | 2878 | { |
e0082a72 | 2879 | int cuid; |
172890a2 RK |
2880 | unsigned int regno; |
2881 | int i; | |
e0082a72 | 2882 | basic_block bb; |
7506f491 DE |
2883 | |
2884 | /* For each block | |
2885 | For each set bit in `gen' of the block (i.e each insn which | |
ac7c5af5 JL |
2886 | generates a definition in the block) |
2887 | Call the reg set by the insn corresponding to that bit regx | |
2888 | Look at the linked list starting at reg_set_table[regx] | |
2889 | For each setting of regx in the linked list, which is not in | |
2890 | this block | |
6d2f8887 | 2891 | Set the bit in `kill' corresponding to that insn. */ |
e0082a72 | 2892 | FOR_EACH_BB (bb) |
c4c81601 | 2893 | for (cuid = 0; cuid < max_cuid; cuid++) |
e0082a72 | 2894 | if (TEST_BIT (rd_gen[bb->index], cuid)) |
7506f491 | 2895 | { |
c4c81601 RK |
2896 | rtx insn = CUID_INSN (cuid); |
2897 | rtx pat = PATTERN (insn); | |
7506f491 | 2898 | |
c4c81601 RK |
2899 | if (GET_CODE (insn) == CALL_INSN) |
2900 | { | |
2901 | for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) | |
4e2db584 | 2902 | if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno)) |
e0082a72 | 2903 | handle_rd_kill_set (insn, regno, bb); |
c4c81601 | 2904 | } |
7506f491 | 2905 | |
c4c81601 RK |
2906 | if (GET_CODE (pat) == PARALLEL) |
2907 | { | |
2908 | for (i = XVECLEN (pat, 0) - 1; i >= 0; i--) | |
7506f491 | 2909 | { |
c4c81601 | 2910 | enum rtx_code code = GET_CODE (XVECEXP (pat, 0, i)); |
7506f491 | 2911 | |
c4c81601 RK |
2912 | if ((code == SET || code == CLOBBER) |
2913 | && GET_CODE (XEXP (XVECEXP (pat, 0, i), 0)) == REG) | |
2914 | handle_rd_kill_set (insn, | |
2915 | REGNO (XEXP (XVECEXP (pat, 0, i), 0)), | |
e0082a72 | 2916 | bb); |
ac7c5af5 | 2917 | } |
ac7c5af5 | 2918 | } |
c4c81601 RK |
2919 | else if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == REG) |
2920 | /* Each setting of this register outside of this block | |
2921 | must be marked in the set of kills in this block. */ | |
e0082a72 | 2922 | handle_rd_kill_set (insn, REGNO (SET_DEST (pat)), bb); |
7506f491 | 2923 | } |
7506f491 DE |
2924 | } |
2925 | ||
589005ff | 2926 | /* Compute the reaching definitions as in |
7506f491 DE |
2927 | Compilers Principles, Techniques, and Tools. Aho, Sethi, Ullman, |
2928 | Chapter 10. It is the same algorithm as used for computing available | |
2929 | expressions but applied to the gens and kills of reaching definitions. */ | |
2930 | ||
2931 | static void | |
1d088dee | 2932 | compute_rd (void) |
7506f491 | 2933 | { |
e0082a72 ZD |
2934 | int changed, passes; |
2935 | basic_block bb; | |
7506f491 | 2936 | |
e0082a72 ZD |
2937 | FOR_EACH_BB (bb) |
2938 | sbitmap_copy (rd_out[bb->index] /*dst*/, rd_gen[bb->index] /*src*/); | |
7506f491 DE |
2939 | |
2940 | passes = 0; | |
2941 | changed = 1; | |
2942 | while (changed) | |
2943 | { | |
2944 | changed = 0; | |
e0082a72 | 2945 | FOR_EACH_BB (bb) |
ac7c5af5 | 2946 | { |
e0082a72 ZD |
2947 | sbitmap_union_of_preds (reaching_defs[bb->index], rd_out, bb->index); |
2948 | changed |= sbitmap_union_of_diff_cg (rd_out[bb->index], rd_gen[bb->index], | |
2949 | reaching_defs[bb->index], rd_kill[bb->index]); | |
ac7c5af5 | 2950 | } |
7506f491 DE |
2951 | passes++; |
2952 | } | |
2953 | ||
2954 | if (gcse_file) | |
2955 | fprintf (gcse_file, "reaching def computation: %d passes\n", passes); | |
2956 | } | |
2957 | \f | |
2958 | /* Classic GCSE available expression support. */ | |
2959 | ||
2960 | /* Allocate memory for available expression computation. */ | |
2961 | ||
2962 | static void | |
1d088dee | 2963 | alloc_avail_expr_mem (int n_blocks, int n_exprs) |
7506f491 | 2964 | { |
703ad42b | 2965 | ae_kill = sbitmap_vector_alloc (n_blocks, n_exprs); |
d55bc081 | 2966 | sbitmap_vector_zero (ae_kill, n_blocks); |
7506f491 | 2967 | |
703ad42b | 2968 | ae_gen = sbitmap_vector_alloc (n_blocks, n_exprs); |
d55bc081 | 2969 | sbitmap_vector_zero (ae_gen, n_blocks); |
7506f491 | 2970 | |
703ad42b | 2971 | ae_in = sbitmap_vector_alloc (n_blocks, n_exprs); |
d55bc081 | 2972 | sbitmap_vector_zero (ae_in, n_blocks); |
7506f491 | 2973 | |
703ad42b | 2974 | ae_out = sbitmap_vector_alloc (n_blocks, n_exprs); |
d55bc081 | 2975 | sbitmap_vector_zero (ae_out, n_blocks); |
7506f491 DE |
2976 | } |
2977 | ||
2978 | static void | |
1d088dee | 2979 | free_avail_expr_mem (void) |
7506f491 | 2980 | { |
5a660bff DB |
2981 | sbitmap_vector_free (ae_kill); |
2982 | sbitmap_vector_free (ae_gen); | |
2983 | sbitmap_vector_free (ae_in); | |
2984 | sbitmap_vector_free (ae_out); | |
7506f491 DE |
2985 | } |
2986 | ||
2987 | /* Compute the set of available expressions generated in each basic block. */ | |
2988 | ||
2989 | static void | |
1d088dee | 2990 | compute_ae_gen (struct hash_table *expr_hash_table) |
7506f491 | 2991 | { |
2e653e39 | 2992 | unsigned int i; |
c4c81601 RK |
2993 | struct expr *expr; |
2994 | struct occr *occr; | |
7506f491 DE |
2995 | |
2996 | /* For each recorded occurrence of each expression, set ae_gen[bb][expr]. | |
2997 | This is all we have to do because an expression is not recorded if it | |
2998 | is not available, and the only expressions we want to work with are the | |
2999 | ones that are recorded. */ | |
02280659 ZD |
3000 | for (i = 0; i < expr_hash_table->size; i++) |
3001 | for (expr = expr_hash_table->table[i]; expr != 0; expr = expr->next_same_hash) | |
c4c81601 RK |
3002 | for (occr = expr->avail_occr; occr != 0; occr = occr->next) |
3003 | SET_BIT (ae_gen[BLOCK_NUM (occr->insn)], expr->bitmap_index); | |
7506f491 DE |
3004 | } |
3005 | ||
cc2902df | 3006 | /* Return nonzero if expression X is killed in BB. */ |
7506f491 DE |
3007 | |
3008 | static int | |
1d088dee | 3009 | expr_killed_p (rtx x, basic_block bb) |
7506f491 | 3010 | { |
c4c81601 | 3011 | int i, j; |
7506f491 | 3012 | enum rtx_code code; |
6f7d635c | 3013 | const char *fmt; |
7506f491 | 3014 | |
7506f491 DE |
3015 | if (x == 0) |
3016 | return 1; | |
3017 | ||
3018 | code = GET_CODE (x); | |
3019 | switch (code) | |
3020 | { | |
3021 | case REG: | |
0b17ab2f | 3022 | return TEST_BIT (reg_set_in_block[bb->index], REGNO (x)); |
7506f491 DE |
3023 | |
3024 | case MEM: | |
a13d4ebf AM |
3025 | if (load_killed_in_block_p (bb, get_max_uid () + 1, x, 0)) |
3026 | return 1; | |
c4c81601 RK |
3027 | else |
3028 | return expr_killed_p (XEXP (x, 0), bb); | |
7506f491 DE |
3029 | |
3030 | case PC: | |
3031 | case CC0: /*FIXME*/ | |
3032 | case CONST: | |
3033 | case CONST_INT: | |
3034 | case CONST_DOUBLE: | |
69ef87e2 | 3035 | case CONST_VECTOR: |
7506f491 DE |
3036 | case SYMBOL_REF: |
3037 | case LABEL_REF: | |
3038 | case ADDR_VEC: | |
3039 | case ADDR_DIFF_VEC: | |
3040 | return 0; | |
3041 | ||
3042 | default: | |
3043 | break; | |
3044 | } | |
3045 | ||
c4c81601 | 3046 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
7506f491 DE |
3047 | { |
3048 | if (fmt[i] == 'e') | |
3049 | { | |
7506f491 DE |
3050 | /* If we are about to do the last recursive call |
3051 | needed at this level, change it into iteration. | |
3052 | This function is called enough to be worth it. */ | |
3053 | if (i == 0) | |
c4c81601 RK |
3054 | return expr_killed_p (XEXP (x, i), bb); |
3055 | else if (expr_killed_p (XEXP (x, i), bb)) | |
7506f491 DE |
3056 | return 1; |
3057 | } | |
3058 | else if (fmt[i] == 'E') | |
c4c81601 RK |
3059 | for (j = 0; j < XVECLEN (x, i); j++) |
3060 | if (expr_killed_p (XVECEXP (x, i, j), bb)) | |
3061 | return 1; | |
7506f491 DE |
3062 | } |
3063 | ||
3064 | return 0; | |
3065 | } | |
3066 | ||
3067 | /* Compute the set of available expressions killed in each basic block. */ | |
3068 | ||
3069 | static void | |
1d088dee AJ |
3070 | compute_ae_kill (sbitmap *ae_gen, sbitmap *ae_kill, |
3071 | struct hash_table *expr_hash_table) | |
7506f491 | 3072 | { |
e0082a72 | 3073 | basic_block bb; |
2e653e39 | 3074 | unsigned int i; |
c4c81601 | 3075 | struct expr *expr; |
7506f491 | 3076 | |
e0082a72 | 3077 | FOR_EACH_BB (bb) |
02280659 ZD |
3078 | for (i = 0; i < expr_hash_table->size; i++) |
3079 | for (expr = expr_hash_table->table[i]; expr; expr = expr->next_same_hash) | |
7506f491 | 3080 | { |
c4c81601 | 3081 | /* Skip EXPR if generated in this block. */ |
e0082a72 | 3082 | if (TEST_BIT (ae_gen[bb->index], expr->bitmap_index)) |
c4c81601 | 3083 | continue; |
7506f491 | 3084 | |
e0082a72 ZD |
3085 | if (expr_killed_p (expr->expr, bb)) |
3086 | SET_BIT (ae_kill[bb->index], expr->bitmap_index); | |
7506f491 | 3087 | } |
7506f491 | 3088 | } |
7506f491 DE |
3089 | \f |
3090 | /* Actually perform the Classic GCSE optimizations. */ | |
3091 | ||
cc2902df | 3092 | /* Return nonzero if occurrence OCCR of expression EXPR reaches block BB. |
7506f491 | 3093 | |
cc2902df | 3094 | CHECK_SELF_LOOP is nonzero if we should consider a block reaching itself |
7506f491 DE |
3095 | as a positive reach. We want to do this when there are two computations |
3096 | of the expression in the block. | |
3097 | ||
3098 | VISITED is a pointer to a working buffer for tracking which BB's have | |
3099 | been visited. It is NULL for the top-level call. | |
3100 | ||
3101 | We treat reaching expressions that go through blocks containing the same | |
3102 | reaching expression as "not reaching". E.g. if EXPR is generated in blocks | |
3103 | 2 and 3, INSN is in block 4, and 2->3->4, we treat the expression in block | |
3104 | 2 as not reaching. The intent is to improve the probability of finding | |
3105 | only one reaching expression and to reduce register lifetimes by picking | |
3106 | the closest such expression. */ | |
3107 | ||
3108 | static int | |
1d088dee AJ |
3109 | expr_reaches_here_p_work (struct occr *occr, struct expr *expr, |
3110 | basic_block bb, int check_self_loop, char *visited) | |
7506f491 | 3111 | { |
36349f8b | 3112 | edge pred; |
7506f491 | 3113 | |
e2d2ed72 | 3114 | for (pred = bb->pred; pred != NULL; pred = pred->pred_next) |
7506f491 | 3115 | { |
e2d2ed72 | 3116 | basic_block pred_bb = pred->src; |
7506f491 | 3117 | |
0b17ab2f | 3118 | if (visited[pred_bb->index]) |
c4c81601 | 3119 | /* This predecessor has already been visited. Nothing to do. */ |
7506f491 | 3120 | ; |
7506f491 | 3121 | else if (pred_bb == bb) |
ac7c5af5 | 3122 | { |
7506f491 DE |
3123 | /* BB loops on itself. */ |
3124 | if (check_self_loop | |
0b17ab2f RH |
3125 | && TEST_BIT (ae_gen[pred_bb->index], expr->bitmap_index) |
3126 | && BLOCK_NUM (occr->insn) == pred_bb->index) | |
7506f491 | 3127 | return 1; |
c4c81601 | 3128 | |
0b17ab2f | 3129 | visited[pred_bb->index] = 1; |
ac7c5af5 | 3130 | } |
c4c81601 | 3131 | |
7506f491 | 3132 | /* Ignore this predecessor if it kills the expression. */ |
0b17ab2f RH |
3133 | else if (TEST_BIT (ae_kill[pred_bb->index], expr->bitmap_index)) |
3134 | visited[pred_bb->index] = 1; | |
c4c81601 | 3135 | |
7506f491 | 3136 | /* Does this predecessor generate this expression? */ |
0b17ab2f | 3137 | else if (TEST_BIT (ae_gen[pred_bb->index], expr->bitmap_index)) |
7506f491 DE |
3138 | { |
3139 | /* Is this the occurrence we're looking for? | |
3140 | Note that there's only one generating occurrence per block | |
3141 | so we just need to check the block number. */ | |
0b17ab2f | 3142 | if (BLOCK_NUM (occr->insn) == pred_bb->index) |
7506f491 | 3143 | return 1; |
c4c81601 | 3144 | |
0b17ab2f | 3145 | visited[pred_bb->index] = 1; |
7506f491 | 3146 | } |
c4c81601 | 3147 | |
7506f491 DE |
3148 | /* Neither gen nor kill. */ |
3149 | else | |
ac7c5af5 | 3150 | { |
0b17ab2f | 3151 | visited[pred_bb->index] = 1; |
589005ff | 3152 | if (expr_reaches_here_p_work (occr, expr, pred_bb, check_self_loop, |
283a2545 | 3153 | visited)) |
c4c81601 | 3154 | |
7506f491 | 3155 | return 1; |
ac7c5af5 | 3156 | } |
7506f491 DE |
3157 | } |
3158 | ||
3159 | /* All paths have been checked. */ | |
3160 | return 0; | |
3161 | } | |
3162 | ||
283a2545 | 3163 | /* This wrapper for expr_reaches_here_p_work() is to ensure that any |
dc297297 | 3164 | memory allocated for that function is returned. */ |
283a2545 RL |
3165 | |
3166 | static int | |
1d088dee AJ |
3167 | expr_reaches_here_p (struct occr *occr, struct expr *expr, basic_block bb, |
3168 | int check_self_loop) | |
283a2545 RL |
3169 | { |
3170 | int rval; | |
703ad42b | 3171 | char *visited = xcalloc (last_basic_block, 1); |
283a2545 | 3172 | |
c4c81601 | 3173 | rval = expr_reaches_here_p_work (occr, expr, bb, check_self_loop, visited); |
589005ff | 3174 | |
283a2545 | 3175 | free (visited); |
c4c81601 | 3176 | return rval; |
283a2545 RL |
3177 | } |
3178 | ||
7506f491 DE |
3179 | /* Return the instruction that computes EXPR that reaches INSN's basic block. |
3180 | If there is more than one such instruction, return NULL. | |
3181 | ||
3182 | Called only by handle_avail_expr. */ | |
3183 | ||
3184 | static rtx | |
1d088dee | 3185 | computing_insn (struct expr *expr, rtx insn) |
7506f491 | 3186 | { |
e2d2ed72 | 3187 | basic_block bb = BLOCK_FOR_INSN (insn); |
7506f491 DE |
3188 | |
3189 | if (expr->avail_occr->next == NULL) | |
589005ff | 3190 | { |
e2d2ed72 | 3191 | if (BLOCK_FOR_INSN (expr->avail_occr->insn) == bb) |
c4c81601 RK |
3192 | /* The available expression is actually itself |
3193 | (i.e. a loop in the flow graph) so do nothing. */ | |
3194 | return NULL; | |
3195 | ||
7506f491 DE |
3196 | /* (FIXME) Case that we found a pattern that was created by |
3197 | a substitution that took place. */ | |
3198 | return expr->avail_occr->insn; | |
3199 | } | |
3200 | else | |
3201 | { | |
3202 | /* Pattern is computed more than once. | |
589005ff | 3203 | Search backwards from this insn to see how many of these |
7506f491 DE |
3204 | computations actually reach this insn. */ |
3205 | struct occr *occr; | |
3206 | rtx insn_computes_expr = NULL; | |
3207 | int can_reach = 0; | |
3208 | ||
3209 | for (occr = expr->avail_occr; occr != NULL; occr = occr->next) | |
3210 | { | |
e2d2ed72 | 3211 | if (BLOCK_FOR_INSN (occr->insn) == bb) |
7506f491 DE |
3212 | { |
3213 | /* The expression is generated in this block. | |
3214 | The only time we care about this is when the expression | |
3215 | is generated later in the block [and thus there's a loop]. | |
3216 | We let the normal cse pass handle the other cases. */ | |
c4c81601 RK |
3217 | if (INSN_CUID (insn) < INSN_CUID (occr->insn) |
3218 | && expr_reaches_here_p (occr, expr, bb, 1)) | |
7506f491 DE |
3219 | { |
3220 | can_reach++; | |
3221 | if (can_reach > 1) | |
3222 | return NULL; | |
c4c81601 | 3223 | |
7506f491 DE |
3224 | insn_computes_expr = occr->insn; |
3225 | } | |
3226 | } | |
c4c81601 RK |
3227 | else if (expr_reaches_here_p (occr, expr, bb, 0)) |
3228 | { | |
3229 | can_reach++; | |
3230 | if (can_reach > 1) | |
3231 | return NULL; | |
3232 | ||
3233 | insn_computes_expr = occr->insn; | |
3234 | } | |
7506f491 DE |
3235 | } |
3236 | ||
3237 | if (insn_computes_expr == NULL) | |
3238 | abort (); | |
c4c81601 | 3239 | |
7506f491 DE |
3240 | return insn_computes_expr; |
3241 | } | |
3242 | } | |
3243 | ||
cc2902df | 3244 | /* Return nonzero if the definition in DEF_INSN can reach INSN. |
7506f491 DE |
3245 | Only called by can_disregard_other_sets. */ |
3246 | ||
3247 | static int | |
1d088dee | 3248 | def_reaches_here_p (rtx insn, rtx def_insn) |
7506f491 DE |
3249 | { |
3250 | rtx reg; | |
3251 | ||
3252 | if (TEST_BIT (reaching_defs[BLOCK_NUM (insn)], INSN_CUID (def_insn))) | |
3253 | return 1; | |
3254 | ||
3255 | if (BLOCK_NUM (insn) == BLOCK_NUM (def_insn)) | |
3256 | { | |
3257 | if (INSN_CUID (def_insn) < INSN_CUID (insn)) | |
ac7c5af5 | 3258 | { |
7506f491 DE |
3259 | if (GET_CODE (PATTERN (def_insn)) == PARALLEL) |
3260 | return 1; | |
c4c81601 | 3261 | else if (GET_CODE (PATTERN (def_insn)) == CLOBBER) |
7506f491 DE |
3262 | reg = XEXP (PATTERN (def_insn), 0); |
3263 | else if (GET_CODE (PATTERN (def_insn)) == SET) | |
3264 | reg = SET_DEST (PATTERN (def_insn)); | |
3265 | else | |
3266 | abort (); | |
c4c81601 | 3267 | |
7506f491 DE |
3268 | return ! reg_set_between_p (reg, NEXT_INSN (def_insn), insn); |
3269 | } | |
3270 | else | |
3271 | return 0; | |
3272 | } | |
3273 | ||
3274 | return 0; | |
3275 | } | |
3276 | ||
cc2902df | 3277 | /* Return nonzero if *ADDR_THIS_REG can only have one value at INSN. The |
c4c81601 RK |
3278 | value returned is the number of definitions that reach INSN. Returning a |
3279 | value of zero means that [maybe] more than one definition reaches INSN and | |
3280 | the caller can't perform whatever optimization it is trying. i.e. it is | |
3281 | always safe to return zero. */ | |
7506f491 DE |
3282 | |
3283 | static int | |
1d088dee | 3284 | can_disregard_other_sets (struct reg_set **addr_this_reg, rtx insn, int for_combine) |
7506f491 DE |
3285 | { |
3286 | int number_of_reaching_defs = 0; | |
c4c81601 | 3287 | struct reg_set *this_reg; |
7506f491 | 3288 | |
c4c81601 RK |
3289 | for (this_reg = *addr_this_reg; this_reg != 0; this_reg = this_reg->next) |
3290 | if (def_reaches_here_p (insn, this_reg->insn)) | |
3291 | { | |
3292 | number_of_reaching_defs++; | |
3293 | /* Ignore parallels for now. */ | |
3294 | if (GET_CODE (PATTERN (this_reg->insn)) == PARALLEL) | |
3295 | return 0; | |
3296 | ||
3297 | if (!for_combine | |
3298 | && (GET_CODE (PATTERN (this_reg->insn)) == CLOBBER | |
3299 | || ! rtx_equal_p (SET_SRC (PATTERN (this_reg->insn)), | |
3300 | SET_SRC (PATTERN (insn))))) | |
3301 | /* A setting of the reg to a different value reaches INSN. */ | |
3302 | return 0; | |
3303 | ||
3304 | if (number_of_reaching_defs > 1) | |
3305 | { | |
3306 | /* If in this setting the value the register is being set to is | |
3307 | equal to the previous value the register was set to and this | |
3308 | setting reaches the insn we are trying to do the substitution | |
3309 | on then we are ok. */ | |
3310 | if (GET_CODE (PATTERN (this_reg->insn)) == CLOBBER) | |
7506f491 | 3311 | return 0; |
c4c81601 RK |
3312 | else if (! rtx_equal_p (SET_SRC (PATTERN (this_reg->insn)), |
3313 | SET_SRC (PATTERN (insn)))) | |
3314 | return 0; | |
3315 | } | |
7506f491 | 3316 | |
589005ff | 3317 | *addr_this_reg = this_reg; |
c4c81601 | 3318 | } |
7506f491 DE |
3319 | |
3320 | return number_of_reaching_defs; | |
3321 | } | |
3322 | ||
3323 | /* Expression computed by insn is available and the substitution is legal, | |
3324 | so try to perform the substitution. | |
3325 | ||
cc2902df | 3326 | The result is nonzero if any changes were made. */ |
7506f491 DE |
3327 | |
3328 | static int | |
1d088dee | 3329 | handle_avail_expr (rtx insn, struct expr *expr) |
7506f491 | 3330 | { |
0631e0bf | 3331 | rtx pat, insn_computes_expr, expr_set; |
7506f491 DE |
3332 | rtx to; |
3333 | struct reg_set *this_reg; | |
3334 | int found_setting, use_src; | |
3335 | int changed = 0; | |
3336 | ||
3337 | /* We only handle the case where one computation of the expression | |
3338 | reaches this instruction. */ | |
3339 | insn_computes_expr = computing_insn (expr, insn); | |
3340 | if (insn_computes_expr == NULL) | |
3341 | return 0; | |
0631e0bf JH |
3342 | expr_set = single_set (insn_computes_expr); |
3343 | if (!expr_set) | |
3344 | abort (); | |
7506f491 DE |
3345 | |
3346 | found_setting = 0; | |
3347 | use_src = 0; | |
3348 | ||
3349 | /* At this point we know only one computation of EXPR outside of this | |
3350 | block reaches this insn. Now try to find a register that the | |
3351 | expression is computed into. */ | |
0631e0bf | 3352 | if (GET_CODE (SET_SRC (expr_set)) == REG) |
7506f491 DE |
3353 | { |
3354 | /* This is the case when the available expression that reaches | |
3355 | here has already been handled as an available expression. */ | |
770ae6cc | 3356 | unsigned int regnum_for_replacing |
0631e0bf | 3357 | = REGNO (SET_SRC (expr_set)); |
c4c81601 | 3358 | |
7506f491 DE |
3359 | /* If the register was created by GCSE we can't use `reg_set_table', |
3360 | however we know it's set only once. */ | |
3361 | if (regnum_for_replacing >= max_gcse_regno | |
3362 | /* If the register the expression is computed into is set only once, | |
3363 | or only one set reaches this insn, we can use it. */ | |
3364 | || (((this_reg = reg_set_table[regnum_for_replacing]), | |
3365 | this_reg->next == NULL) | |
3366 | || can_disregard_other_sets (&this_reg, insn, 0))) | |
8e42ace1 KH |
3367 | { |
3368 | use_src = 1; | |
3369 | found_setting = 1; | |
3370 | } | |
7506f491 DE |
3371 | } |
3372 | ||
3373 | if (!found_setting) | |
3374 | { | |
770ae6cc | 3375 | unsigned int regnum_for_replacing |
0631e0bf | 3376 | = REGNO (SET_DEST (expr_set)); |
c4c81601 | 3377 | |
7506f491 DE |
3378 | /* This shouldn't happen. */ |
3379 | if (regnum_for_replacing >= max_gcse_regno) | |
3380 | abort (); | |
c4c81601 | 3381 | |
7506f491 | 3382 | this_reg = reg_set_table[regnum_for_replacing]; |
c4c81601 | 3383 | |
7506f491 DE |
3384 | /* If the register the expression is computed into is set only once, |
3385 | or only one set reaches this insn, use it. */ | |
3386 | if (this_reg->next == NULL | |
3387 | || can_disregard_other_sets (&this_reg, insn, 0)) | |
3388 | found_setting = 1; | |
3389 | } | |
3390 | ||
3391 | if (found_setting) | |
3392 | { | |
3393 | pat = PATTERN (insn); | |
3394 | if (use_src) | |
0631e0bf | 3395 | to = SET_SRC (expr_set); |
7506f491 | 3396 | else |
0631e0bf | 3397 | to = SET_DEST (expr_set); |
7506f491 DE |
3398 | changed = validate_change (insn, &SET_SRC (pat), to, 0); |
3399 | ||
3400 | /* We should be able to ignore the return code from validate_change but | |
3401 | to play it safe we check. */ | |
3402 | if (changed) | |
3403 | { | |
3404 | gcse_subst_count++; | |
3405 | if (gcse_file != NULL) | |
3406 | { | |
c4c81601 RK |
3407 | fprintf (gcse_file, "GCSE: Replacing the source in insn %d with", |
3408 | INSN_UID (insn)); | |
3409 | fprintf (gcse_file, " reg %d %s insn %d\n", | |
3410 | REGNO (to), use_src ? "from" : "set in", | |
7506f491 DE |
3411 | INSN_UID (insn_computes_expr)); |
3412 | } | |
7506f491 DE |
3413 | } |
3414 | } | |
c4c81601 | 3415 | |
7506f491 DE |
3416 | /* The register that the expr is computed into is set more than once. */ |
3417 | else if (1 /*expensive_op(this_pattrn->op) && do_expensive_gcse)*/) | |
3418 | { | |
3419 | /* Insert an insn after insnx that copies the reg set in insnx | |
3420 | into a new pseudo register call this new register REGN. | |
3421 | From insnb until end of basic block or until REGB is set | |
3422 | replace all uses of REGB with REGN. */ | |
3423 | rtx new_insn; | |
3424 | ||
0631e0bf | 3425 | to = gen_reg_rtx (GET_MODE (SET_DEST (expr_set))); |
7506f491 DE |
3426 | |
3427 | /* Generate the new insn. */ | |
3428 | /* ??? If the change fails, we return 0, even though we created | |
3429 | an insn. I think this is ok. */ | |
9e6a5703 JC |
3430 | new_insn |
3431 | = emit_insn_after (gen_rtx_SET (VOIDmode, to, | |
0631e0bf | 3432 | SET_DEST (expr_set)), |
c4c81601 RK |
3433 | insn_computes_expr); |
3434 | ||
7506f491 DE |
3435 | /* Keep register set table up to date. */ |
3436 | record_one_set (REGNO (to), new_insn); | |
3437 | ||
3438 | gcse_create_count++; | |
3439 | if (gcse_file != NULL) | |
ac7c5af5 | 3440 | { |
c4c81601 | 3441 | fprintf (gcse_file, "GCSE: Creating insn %d to copy value of reg %d", |
7506f491 | 3442 | INSN_UID (NEXT_INSN (insn_computes_expr)), |
c4c81601 RK |
3443 | REGNO (SET_SRC (PATTERN (NEXT_INSN (insn_computes_expr))))); |
3444 | fprintf (gcse_file, ", computed in insn %d,\n", | |
7506f491 | 3445 | INSN_UID (insn_computes_expr)); |
c4c81601 RK |
3446 | fprintf (gcse_file, " into newly allocated reg %d\n", |
3447 | REGNO (to)); | |
ac7c5af5 | 3448 | } |
7506f491 DE |
3449 | |
3450 | pat = PATTERN (insn); | |
3451 | ||
3452 | /* Do register replacement for INSN. */ | |
3453 | changed = validate_change (insn, &SET_SRC (pat), | |
c4c81601 RK |
3454 | SET_DEST (PATTERN |
3455 | (NEXT_INSN (insn_computes_expr))), | |
7506f491 DE |
3456 | 0); |
3457 | ||
3458 | /* We should be able to ignore the return code from validate_change but | |
3459 | to play it safe we check. */ | |
3460 | if (changed) | |
3461 | { | |
3462 | gcse_subst_count++; | |
3463 | if (gcse_file != NULL) | |
3464 | { | |
c4c81601 RK |
3465 | fprintf (gcse_file, |
3466 | "GCSE: Replacing the source in insn %d with reg %d ", | |
7506f491 | 3467 | INSN_UID (insn), |
c4c81601 RK |
3468 | REGNO (SET_DEST (PATTERN (NEXT_INSN |
3469 | (insn_computes_expr))))); | |
3470 | fprintf (gcse_file, "set in insn %d\n", | |
589005ff | 3471 | INSN_UID (insn_computes_expr)); |
7506f491 | 3472 | } |
7506f491 DE |
3473 | } |
3474 | } | |
3475 | ||
3476 | return changed; | |
3477 | } | |
3478 | ||
c4c81601 RK |
3479 | /* Perform classic GCSE. This is called by one_classic_gcse_pass after all |
3480 | the dataflow analysis has been done. | |
7506f491 | 3481 | |
cc2902df | 3482 | The result is nonzero if a change was made. */ |
7506f491 DE |
3483 | |
3484 | static int | |
1d088dee | 3485 | classic_gcse (void) |
7506f491 | 3486 | { |
e0082a72 | 3487 | int changed; |
7506f491 | 3488 | rtx insn; |
e0082a72 | 3489 | basic_block bb; |
7506f491 DE |
3490 | |
3491 | /* Note we start at block 1. */ | |
3492 | ||
e0082a72 ZD |
3493 | if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR) |
3494 | return 0; | |
3495 | ||
7506f491 | 3496 | changed = 0; |
e0082a72 | 3497 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, EXIT_BLOCK_PTR, next_bb) |
7506f491 DE |
3498 | { |
3499 | /* Reset tables used to keep track of what's still valid [since the | |
3500 | start of the block]. */ | |
3501 | reset_opr_set_tables (); | |
3502 | ||
e0082a72 ZD |
3503 | for (insn = bb->head; |
3504 | insn != NULL && insn != NEXT_INSN (bb->end); | |
7506f491 DE |
3505 | insn = NEXT_INSN (insn)) |
3506 | { | |
3507 | /* Is insn of form (set (pseudo-reg) ...)? */ | |
7506f491 DE |
3508 | if (GET_CODE (insn) == INSN |
3509 | && GET_CODE (PATTERN (insn)) == SET | |
3510 | && GET_CODE (SET_DEST (PATTERN (insn))) == REG | |
3511 | && REGNO (SET_DEST (PATTERN (insn))) >= FIRST_PSEUDO_REGISTER) | |
3512 | { | |
3513 | rtx pat = PATTERN (insn); | |
3514 | rtx src = SET_SRC (pat); | |
3515 | struct expr *expr; | |
3516 | ||
3517 | if (want_to_gcse_p (src) | |
3518 | /* Is the expression recorded? */ | |
02280659 | 3519 | && ((expr = lookup_expr (src, &expr_hash_table)) != NULL) |
7506f491 DE |
3520 | /* Is the expression available [at the start of the |
3521 | block]? */ | |
e0082a72 | 3522 | && TEST_BIT (ae_in[bb->index], expr->bitmap_index) |
7506f491 DE |
3523 | /* Are the operands unchanged since the start of the |
3524 | block? */ | |
3525 | && oprs_not_set_p (src, insn)) | |
3526 | changed |= handle_avail_expr (insn, expr); | |
3527 | } | |
3528 | ||
3529 | /* Keep track of everything modified by this insn. */ | |
3530 | /* ??? Need to be careful w.r.t. mods done to INSN. */ | |
2c3c49de | 3531 | if (INSN_P (insn)) |
7506f491 | 3532 | mark_oprs_set (insn); |
ac7c5af5 | 3533 | } |
7506f491 DE |
3534 | } |
3535 | ||
3536 | return changed; | |
3537 | } | |
3538 | ||
3539 | /* Top level routine to perform one classic GCSE pass. | |
3540 | ||
cc2902df | 3541 | Return nonzero if a change was made. */ |
7506f491 DE |
3542 | |
3543 | static int | |
1d088dee | 3544 | one_classic_gcse_pass (int pass) |
7506f491 DE |
3545 | { |
3546 | int changed = 0; | |
3547 | ||
3548 | gcse_subst_count = 0; | |
3549 | gcse_create_count = 0; | |
3550 | ||
02280659 | 3551 | alloc_hash_table (max_cuid, &expr_hash_table, 0); |
d55bc081 | 3552 | alloc_rd_mem (last_basic_block, max_cuid); |
02280659 | 3553 | compute_hash_table (&expr_hash_table); |
7506f491 | 3554 | if (gcse_file) |
02280659 | 3555 | dump_hash_table (gcse_file, "Expression", &expr_hash_table); |
c4c81601 | 3556 | |
02280659 | 3557 | if (expr_hash_table.n_elems > 0) |
7506f491 DE |
3558 | { |
3559 | compute_kill_rd (); | |
3560 | compute_rd (); | |
02280659 ZD |
3561 | alloc_avail_expr_mem (last_basic_block, expr_hash_table.n_elems); |
3562 | compute_ae_gen (&expr_hash_table); | |
3563 | compute_ae_kill (ae_gen, ae_kill, &expr_hash_table); | |
bd0eaec2 | 3564 | compute_available (ae_gen, ae_kill, ae_out, ae_in); |
7506f491 DE |
3565 | changed = classic_gcse (); |
3566 | free_avail_expr_mem (); | |
3567 | } | |
c4c81601 | 3568 | |
7506f491 | 3569 | free_rd_mem (); |
02280659 | 3570 | free_hash_table (&expr_hash_table); |
7506f491 DE |
3571 | |
3572 | if (gcse_file) | |
3573 | { | |
3574 | fprintf (gcse_file, "\n"); | |
c4c81601 RK |
3575 | fprintf (gcse_file, "GCSE of %s, pass %d: %d bytes needed, %d substs,", |
3576 | current_function_name, pass, bytes_used, gcse_subst_count); | |
3577 | fprintf (gcse_file, "%d insns created\n", gcse_create_count); | |
7506f491 DE |
3578 | } |
3579 | ||
3580 | return changed; | |
3581 | } | |
3582 | \f | |
3583 | /* Compute copy/constant propagation working variables. */ | |
3584 | ||
3585 | /* Local properties of assignments. */ | |
7506f491 DE |
3586 | static sbitmap *cprop_pavloc; |
3587 | static sbitmap *cprop_absaltered; | |
3588 | ||
3589 | /* Global properties of assignments (computed from the local properties). */ | |
7506f491 DE |
3590 | static sbitmap *cprop_avin; |
3591 | static sbitmap *cprop_avout; | |
3592 | ||
c4c81601 RK |
3593 | /* Allocate vars used for copy/const propagation. N_BLOCKS is the number of |
3594 | basic blocks. N_SETS is the number of sets. */ | |
7506f491 DE |
3595 | |
3596 | static void | |
1d088dee | 3597 | alloc_cprop_mem (int n_blocks, int n_sets) |
7506f491 DE |
3598 | { |
3599 | cprop_pavloc = sbitmap_vector_alloc (n_blocks, n_sets); | |
3600 | cprop_absaltered = sbitmap_vector_alloc (n_blocks, n_sets); | |
3601 | ||
3602 | cprop_avin = sbitmap_vector_alloc (n_blocks, n_sets); | |
3603 | cprop_avout = sbitmap_vector_alloc (n_blocks, n_sets); | |
3604 | } | |
3605 | ||
3606 | /* Free vars used by copy/const propagation. */ | |
3607 | ||
3608 | static void | |
1d088dee | 3609 | free_cprop_mem (void) |
7506f491 | 3610 | { |
5a660bff DB |
3611 | sbitmap_vector_free (cprop_pavloc); |
3612 | sbitmap_vector_free (cprop_absaltered); | |
3613 | sbitmap_vector_free (cprop_avin); | |
3614 | sbitmap_vector_free (cprop_avout); | |
7506f491 DE |
3615 | } |
3616 | ||
c4c81601 RK |
3617 | /* For each block, compute whether X is transparent. X is either an |
3618 | expression or an assignment [though we don't care which, for this context | |
3619 | an assignment is treated as an expression]. For each block where an | |
3620 | element of X is modified, set (SET_P == 1) or reset (SET_P == 0) the INDX | |
3621 | bit in BMAP. */ | |
7506f491 DE |
3622 | |
3623 | static void | |
1d088dee | 3624 | compute_transp (rtx x, int indx, sbitmap *bmap, int set_p) |
7506f491 | 3625 | { |
e0082a72 ZD |
3626 | int i, j; |
3627 | basic_block bb; | |
7506f491 | 3628 | enum rtx_code code; |
c4c81601 | 3629 | reg_set *r; |
6f7d635c | 3630 | const char *fmt; |
7506f491 | 3631 | |
c4c81601 RK |
3632 | /* repeat is used to turn tail-recursion into iteration since GCC |
3633 | can't do it when there's no return value. */ | |
7506f491 DE |
3634 | repeat: |
3635 | ||
3636 | if (x == 0) | |
3637 | return; | |
3638 | ||
3639 | code = GET_CODE (x); | |
3640 | switch (code) | |
3641 | { | |
3642 | case REG: | |
c4c81601 RK |
3643 | if (set_p) |
3644 | { | |
3645 | if (REGNO (x) < FIRST_PSEUDO_REGISTER) | |
3646 | { | |
e0082a72 ZD |
3647 | FOR_EACH_BB (bb) |
3648 | if (TEST_BIT (reg_set_in_block[bb->index], REGNO (x))) | |
3649 | SET_BIT (bmap[bb->index], indx); | |
c4c81601 RK |
3650 | } |
3651 | else | |
3652 | { | |
3653 | for (r = reg_set_table[REGNO (x)]; r != NULL; r = r->next) | |
3654 | SET_BIT (bmap[BLOCK_NUM (r->insn)], indx); | |
3655 | } | |
3656 | } | |
3657 | else | |
3658 | { | |
3659 | if (REGNO (x) < FIRST_PSEUDO_REGISTER) | |
3660 | { | |
e0082a72 ZD |
3661 | FOR_EACH_BB (bb) |
3662 | if (TEST_BIT (reg_set_in_block[bb->index], REGNO (x))) | |
3663 | RESET_BIT (bmap[bb->index], indx); | |
c4c81601 RK |
3664 | } |
3665 | else | |
3666 | { | |
3667 | for (r = reg_set_table[REGNO (x)]; r != NULL; r = r->next) | |
3668 | RESET_BIT (bmap[BLOCK_NUM (r->insn)], indx); | |
3669 | } | |
3670 | } | |
7506f491 | 3671 | |
c4c81601 | 3672 | return; |
7506f491 DE |
3673 | |
3674 | case MEM: | |
e0082a72 | 3675 | FOR_EACH_BB (bb) |
a13d4ebf | 3676 | { |
e0082a72 | 3677 | rtx list_entry = canon_modify_mem_list[bb->index]; |
a13d4ebf AM |
3678 | |
3679 | while (list_entry) | |
3680 | { | |
3681 | rtx dest, dest_addr; | |
3682 | ||
3683 | if (GET_CODE (XEXP (list_entry, 0)) == CALL_INSN) | |
3684 | { | |
3685 | if (set_p) | |
e0082a72 | 3686 | SET_BIT (bmap[bb->index], indx); |
a13d4ebf | 3687 | else |
e0082a72 | 3688 | RESET_BIT (bmap[bb->index], indx); |
a13d4ebf AM |
3689 | break; |
3690 | } | |
3691 | /* LIST_ENTRY must be an INSN of some kind that sets memory. | |
3692 | Examine each hunk of memory that is modified. */ | |
3693 | ||
3694 | dest = XEXP (list_entry, 0); | |
3695 | list_entry = XEXP (list_entry, 1); | |
3696 | dest_addr = XEXP (list_entry, 0); | |
589005ff | 3697 | |
a13d4ebf AM |
3698 | if (canon_true_dependence (dest, GET_MODE (dest), dest_addr, |
3699 | x, rtx_addr_varies_p)) | |
3700 | { | |
3701 | if (set_p) | |
e0082a72 | 3702 | SET_BIT (bmap[bb->index], indx); |
a13d4ebf | 3703 | else |
e0082a72 | 3704 | RESET_BIT (bmap[bb->index], indx); |
a13d4ebf AM |
3705 | break; |
3706 | } | |
3707 | list_entry = XEXP (list_entry, 1); | |
3708 | } | |
3709 | } | |
c4c81601 | 3710 | |
7506f491 DE |
3711 | x = XEXP (x, 0); |
3712 | goto repeat; | |
3713 | ||
3714 | case PC: | |
3715 | case CC0: /*FIXME*/ | |
3716 | case CONST: | |
3717 | case CONST_INT: | |
3718 | case CONST_DOUBLE: | |
69ef87e2 | 3719 | case CONST_VECTOR: |
7506f491 DE |
3720 | case SYMBOL_REF: |
3721 | case LABEL_REF: | |
3722 | case ADDR_VEC: | |
3723 | case ADDR_DIFF_VEC: | |
3724 | return; | |
3725 | ||
3726 | default: | |
3727 | break; | |
3728 | } | |
3729 | ||
c4c81601 | 3730 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
7506f491 DE |
3731 | { |
3732 | if (fmt[i] == 'e') | |
3733 | { | |
7506f491 DE |
3734 | /* If we are about to do the last recursive call |
3735 | needed at this level, change it into iteration. | |
3736 | This function is called enough to be worth it. */ | |
3737 | if (i == 0) | |
3738 | { | |
c4c81601 | 3739 | x = XEXP (x, i); |
7506f491 DE |
3740 | goto repeat; |
3741 | } | |
c4c81601 RK |
3742 | |
3743 | compute_transp (XEXP (x, i), indx, bmap, set_p); | |
7506f491 DE |
3744 | } |
3745 | else if (fmt[i] == 'E') | |
c4c81601 RK |
3746 | for (j = 0; j < XVECLEN (x, i); j++) |
3747 | compute_transp (XVECEXP (x, i, j), indx, bmap, set_p); | |
7506f491 DE |
3748 | } |
3749 | } | |
3750 | ||
7506f491 DE |
3751 | /* Top level routine to do the dataflow analysis needed by copy/const |
3752 | propagation. */ | |
3753 | ||
3754 | static void | |
1d088dee | 3755 | compute_cprop_data (void) |
7506f491 | 3756 | { |
02280659 | 3757 | compute_local_properties (cprop_absaltered, cprop_pavloc, NULL, &set_hash_table); |
ce724250 JL |
3758 | compute_available (cprop_pavloc, cprop_absaltered, |
3759 | cprop_avout, cprop_avin); | |
7506f491 DE |
3760 | } |
3761 | \f | |
3762 | /* Copy/constant propagation. */ | |
3763 | ||
7506f491 DE |
3764 | /* Maximum number of register uses in an insn that we handle. */ |
3765 | #define MAX_USES 8 | |
3766 | ||
3767 | /* Table of uses found in an insn. | |
3768 | Allocated statically to avoid alloc/free complexity and overhead. */ | |
3769 | static struct reg_use reg_use_table[MAX_USES]; | |
3770 | ||
3771 | /* Index into `reg_use_table' while building it. */ | |
3772 | static int reg_use_count; | |
3773 | ||
c4c81601 RK |
3774 | /* Set up a list of register numbers used in INSN. The found uses are stored |
3775 | in `reg_use_table'. `reg_use_count' is initialized to zero before entry, | |
3776 | and contains the number of uses in the table upon exit. | |
7506f491 | 3777 | |
c4c81601 RK |
3778 | ??? If a register appears multiple times we will record it multiple times. |
3779 | This doesn't hurt anything but it will slow things down. */ | |
7506f491 DE |
3780 | |
3781 | static void | |
1d088dee | 3782 | find_used_regs (rtx *xptr, void *data ATTRIBUTE_UNUSED) |
7506f491 | 3783 | { |
c4c81601 | 3784 | int i, j; |
7506f491 | 3785 | enum rtx_code code; |
6f7d635c | 3786 | const char *fmt; |
9e71c818 | 3787 | rtx x = *xptr; |
7506f491 | 3788 | |
c4c81601 RK |
3789 | /* repeat is used to turn tail-recursion into iteration since GCC |
3790 | can't do it when there's no return value. */ | |
7506f491 | 3791 | repeat: |
7506f491 DE |
3792 | if (x == 0) |
3793 | return; | |
3794 | ||
3795 | code = GET_CODE (x); | |
9e71c818 | 3796 | if (REG_P (x)) |
7506f491 | 3797 | { |
7506f491 DE |
3798 | if (reg_use_count == MAX_USES) |
3799 | return; | |
c4c81601 | 3800 | |
7506f491 DE |
3801 | reg_use_table[reg_use_count].reg_rtx = x; |
3802 | reg_use_count++; | |
7506f491 DE |
3803 | } |
3804 | ||
3805 | /* Recursively scan the operands of this expression. */ | |
3806 | ||
c4c81601 | 3807 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
7506f491 DE |
3808 | { |
3809 | if (fmt[i] == 'e') | |
3810 | { | |
3811 | /* If we are about to do the last recursive call | |
3812 | needed at this level, change it into iteration. | |
3813 | This function is called enough to be worth it. */ | |
3814 | if (i == 0) | |
3815 | { | |
3816 | x = XEXP (x, 0); | |
3817 | goto repeat; | |
3818 | } | |
c4c81601 | 3819 | |
9e71c818 | 3820 | find_used_regs (&XEXP (x, i), data); |
7506f491 DE |
3821 | } |
3822 | else if (fmt[i] == 'E') | |
c4c81601 | 3823 | for (j = 0; j < XVECLEN (x, i); j++) |
9e71c818 | 3824 | find_used_regs (&XVECEXP (x, i, j), data); |
7506f491 DE |
3825 | } |
3826 | } | |
3827 | ||
3828 | /* Try to replace all non-SET_DEST occurrences of FROM in INSN with TO. | |
cc2902df | 3829 | Returns nonzero is successful. */ |
7506f491 DE |
3830 | |
3831 | static int | |
1d088dee | 3832 | try_replace_reg (rtx from, rtx to, rtx insn) |
7506f491 | 3833 | { |
172890a2 | 3834 | rtx note = find_reg_equal_equiv_note (insn); |
fb0c0a12 | 3835 | rtx src = 0; |
172890a2 RK |
3836 | int success = 0; |
3837 | rtx set = single_set (insn); | |
833fc3ad | 3838 | |
2b773ee2 JH |
3839 | validate_replace_src_group (from, to, insn); |
3840 | if (num_changes_pending () && apply_change_group ()) | |
3841 | success = 1; | |
9e71c818 | 3842 | |
9feff114 JDA |
3843 | /* Try to simplify SET_SRC if we have substituted a constant. */ |
3844 | if (success && set && CONSTANT_P (to)) | |
3845 | { | |
3846 | src = simplify_rtx (SET_SRC (set)); | |
3847 | ||
3848 | if (src) | |
3849 | validate_change (insn, &SET_SRC (set), src, 0); | |
3850 | } | |
3851 | ||
f305679f | 3852 | if (!success && set && reg_mentioned_p (from, SET_SRC (set))) |
833fc3ad | 3853 | { |
f305679f JH |
3854 | /* If above failed and this is a single set, try to simplify the source of |
3855 | the set given our substitution. We could perhaps try this for multiple | |
3856 | SETs, but it probably won't buy us anything. */ | |
172890a2 RK |
3857 | src = simplify_replace_rtx (SET_SRC (set), from, to); |
3858 | ||
9e71c818 JH |
3859 | if (!rtx_equal_p (src, SET_SRC (set)) |
3860 | && validate_change (insn, &SET_SRC (set), src, 0)) | |
172890a2 | 3861 | success = 1; |
833fc3ad | 3862 | |
bbd288a4 FS |
3863 | /* If we've failed to do replacement, have a single SET, don't already |
3864 | have a note, and have no special SET, add a REG_EQUAL note to not | |
3865 | lose information. */ | |
3866 | if (!success && note == 0 && set != 0 | |
3867 | && GET_CODE (XEXP (set, 0)) != ZERO_EXTRACT | |
3868 | && GET_CODE (XEXP (set, 0)) != SIGN_EXTRACT) | |
f305679f JH |
3869 | note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src)); |
3870 | } | |
e251e2a2 | 3871 | |
172890a2 RK |
3872 | /* If there is already a NOTE, update the expression in it with our |
3873 | replacement. */ | |
3874 | else if (note != 0) | |
3875 | XEXP (note, 0) = simplify_replace_rtx (XEXP (note, 0), from, to); | |
833fc3ad | 3876 | |
172890a2 RK |
3877 | /* REG_EQUAL may get simplified into register. |
3878 | We don't allow that. Remove that note. This code ought | |
fbe5a4a6 | 3879 | not to happen, because previous code ought to synthesize |
172890a2 RK |
3880 | reg-reg move, but be on the safe side. */ |
3881 | if (note && REG_P (XEXP (note, 0))) | |
3882 | remove_note (insn, note); | |
833fc3ad | 3883 | |
833fc3ad JH |
3884 | return success; |
3885 | } | |
c4c81601 RK |
3886 | |
3887 | /* Find a set of REGNOs that are available on entry to INSN's block. Returns | |
3888 | NULL no such set is found. */ | |
7506f491 DE |
3889 | |
3890 | static struct expr * | |
1d088dee | 3891 | find_avail_set (int regno, rtx insn) |
7506f491 | 3892 | { |
cafba495 BS |
3893 | /* SET1 contains the last set found that can be returned to the caller for |
3894 | use in a substitution. */ | |
3895 | struct expr *set1 = 0; | |
589005ff | 3896 | |
cafba495 BS |
3897 | /* Loops are not possible here. To get a loop we would need two sets |
3898 | available at the start of the block containing INSN. ie we would | |
3899 | need two sets like this available at the start of the block: | |
3900 | ||
3901 | (set (reg X) (reg Y)) | |
3902 | (set (reg Y) (reg X)) | |
3903 | ||
3904 | This can not happen since the set of (reg Y) would have killed the | |
3905 | set of (reg X) making it unavailable at the start of this block. */ | |
3906 | while (1) | |
8e42ace1 | 3907 | { |
cafba495 | 3908 | rtx src; |
ceda50e9 | 3909 | struct expr *set = lookup_set (regno, &set_hash_table); |
cafba495 BS |
3910 | |
3911 | /* Find a set that is available at the start of the block | |
3912 | which contains INSN. */ | |
3913 | while (set) | |
3914 | { | |
3915 | if (TEST_BIT (cprop_avin[BLOCK_NUM (insn)], set->bitmap_index)) | |
3916 | break; | |
3917 | set = next_set (regno, set); | |
3918 | } | |
7506f491 | 3919 | |
cafba495 BS |
3920 | /* If no available set was found we've reached the end of the |
3921 | (possibly empty) copy chain. */ | |
3922 | if (set == 0) | |
589005ff | 3923 | break; |
cafba495 BS |
3924 | |
3925 | if (GET_CODE (set->expr) != SET) | |
3926 | abort (); | |
3927 | ||
3928 | src = SET_SRC (set->expr); | |
3929 | ||
3930 | /* We know the set is available. | |
3931 | Now check that SRC is ANTLOC (i.e. none of the source operands | |
589005ff | 3932 | have changed since the start of the block). |
cafba495 BS |
3933 | |
3934 | If the source operand changed, we may still use it for the next | |
3935 | iteration of this loop, but we may not use it for substitutions. */ | |
c4c81601 | 3936 | |
6b2d1c9e | 3937 | if (gcse_constant_p (src) || oprs_not_set_p (src, insn)) |
cafba495 BS |
3938 | set1 = set; |
3939 | ||
3940 | /* If the source of the set is anything except a register, then | |
3941 | we have reached the end of the copy chain. */ | |
3942 | if (GET_CODE (src) != REG) | |
7506f491 | 3943 | break; |
7506f491 | 3944 | |
cafba495 BS |
3945 | /* Follow the copy chain, ie start another iteration of the loop |
3946 | and see if we have an available copy into SRC. */ | |
3947 | regno = REGNO (src); | |
8e42ace1 | 3948 | } |
cafba495 BS |
3949 | |
3950 | /* SET1 holds the last set that was available and anticipatable at | |
3951 | INSN. */ | |
3952 | return set1; | |
7506f491 DE |
3953 | } |
3954 | ||
abd535b6 | 3955 | /* Subroutine of cprop_insn that tries to propagate constants into |
0e3f0221 | 3956 | JUMP_INSNS. JUMP must be a conditional jump. If SETCC is non-NULL |
fbe5a4a6 | 3957 | it is the instruction that immediately precedes JUMP, and must be a |
818b6b7f | 3958 | single SET of a register. FROM is what we will try to replace, |
0e3f0221 | 3959 | SRC is the constant we will try to substitute for it. Returns nonzero |
589005ff | 3960 | if a change was made. */ |
c4c81601 | 3961 | |
abd535b6 | 3962 | static int |
1d088dee | 3963 | cprop_jump (basic_block bb, rtx setcc, rtx jump, rtx from, rtx src) |
abd535b6 | 3964 | { |
bc6688b4 | 3965 | rtx new, set_src, note_src; |
0e3f0221 | 3966 | rtx set = pc_set (jump); |
bc6688b4 | 3967 | rtx note = find_reg_equal_equiv_note (jump); |
0e3f0221 | 3968 | |
bc6688b4 RS |
3969 | if (note) |
3970 | { | |
3971 | note_src = XEXP (note, 0); | |
3972 | if (GET_CODE (note_src) == EXPR_LIST) | |
3973 | note_src = NULL_RTX; | |
3974 | } | |
3975 | else note_src = NULL_RTX; | |
3976 | ||
3977 | /* Prefer REG_EQUAL notes except those containing EXPR_LISTs. */ | |
3978 | set_src = note_src ? note_src : SET_SRC (set); | |
3979 | ||
3980 | /* First substitute the SETCC condition into the JUMP instruction, | |
3981 | then substitute that given values into this expanded JUMP. */ | |
3982 | if (setcc != NULL_RTX | |
48ddd46c JH |
3983 | && !modified_between_p (from, setcc, jump) |
3984 | && !modified_between_p (src, setcc, jump)) | |
b2f02503 | 3985 | { |
bc6688b4 | 3986 | rtx setcc_src; |
b2f02503 | 3987 | rtx setcc_set = single_set (setcc); |
bc6688b4 RS |
3988 | rtx setcc_note = find_reg_equal_equiv_note (setcc); |
3989 | setcc_src = (setcc_note && GET_CODE (XEXP (setcc_note, 0)) != EXPR_LIST) | |
3990 | ? XEXP (setcc_note, 0) : SET_SRC (setcc_set); | |
3991 | set_src = simplify_replace_rtx (set_src, SET_DEST (setcc_set), | |
3992 | setcc_src); | |
b2f02503 | 3993 | } |
0e3f0221 | 3994 | else |
bc6688b4 | 3995 | setcc = NULL_RTX; |
0e3f0221 | 3996 | |
bc6688b4 | 3997 | new = simplify_replace_rtx (set_src, from, src); |
abd535b6 | 3998 | |
bc6688b4 RS |
3999 | /* If no simplification can be made, then try the next register. */ |
4000 | if (rtx_equal_p (new, SET_SRC (set))) | |
9e48c409 | 4001 | return 0; |
589005ff | 4002 | |
7d5ab30e | 4003 | /* If this is now a no-op delete it, otherwise this must be a valid insn. */ |
172890a2 | 4004 | if (new == pc_rtx) |
0e3f0221 | 4005 | delete_insn (jump); |
7d5ab30e | 4006 | else |
abd535b6 | 4007 | { |
48ddd46c JH |
4008 | /* Ensure the value computed inside the jump insn to be equivalent |
4009 | to one computed by setcc. */ | |
bc6688b4 | 4010 | if (setcc && modified_in_p (new, setcc)) |
48ddd46c | 4011 | return 0; |
0e3f0221 | 4012 | if (! validate_change (jump, &SET_SRC (set), new, 0)) |
bc6688b4 RS |
4013 | { |
4014 | /* When (some) constants are not valid in a comparison, and there | |
4015 | are two registers to be replaced by constants before the entire | |
4016 | comparison can be folded into a constant, we need to keep | |
4017 | intermediate information in REG_EQUAL notes. For targets with | |
4018 | separate compare insns, such notes are added by try_replace_reg. | |
4019 | When we have a combined compare-and-branch instruction, however, | |
4020 | we need to attach a note to the branch itself to make this | |
4021 | optimization work. */ | |
4022 | ||
4023 | if (!rtx_equal_p (new, note_src)) | |
4024 | set_unique_reg_note (jump, REG_EQUAL, copy_rtx (new)); | |
4025 | return 0; | |
4026 | } | |
4027 | ||
4028 | /* Remove REG_EQUAL note after simplification. */ | |
4029 | if (note_src) | |
4030 | remove_note (jump, note); | |
abd535b6 | 4031 | |
7d5ab30e JH |
4032 | /* If this has turned into an unconditional jump, |
4033 | then put a barrier after it so that the unreachable | |
4034 | code will be deleted. */ | |
4035 | if (GET_CODE (SET_SRC (set)) == LABEL_REF) | |
0e3f0221 | 4036 | emit_barrier_after (jump); |
7d5ab30e | 4037 | } |
abd535b6 | 4038 | |
0e3f0221 RS |
4039 | #ifdef HAVE_cc0 |
4040 | /* Delete the cc0 setter. */ | |
818b6b7f | 4041 | if (setcc != NULL && CC0_P (SET_DEST (single_set (setcc)))) |
0e3f0221 RS |
4042 | delete_insn (setcc); |
4043 | #endif | |
4044 | ||
172890a2 | 4045 | run_jump_opt_after_gcse = 1; |
c4c81601 | 4046 | |
172890a2 RK |
4047 | const_prop_count++; |
4048 | if (gcse_file != NULL) | |
4049 | { | |
4050 | fprintf (gcse_file, | |
818b6b7f | 4051 | "CONST-PROP: Replacing reg %d in jump_insn %d with constant ", |
0e3f0221 | 4052 | REGNO (from), INSN_UID (jump)); |
172890a2 RK |
4053 | print_rtl (gcse_file, src); |
4054 | fprintf (gcse_file, "\n"); | |
abd535b6 | 4055 | } |
0005550b | 4056 | purge_dead_edges (bb); |
172890a2 RK |
4057 | |
4058 | return 1; | |
abd535b6 BS |
4059 | } |
4060 | ||
ae860ff7 | 4061 | static bool |
1d088dee | 4062 | constprop_register (rtx insn, rtx from, rtx to, int alter_jumps) |
ae860ff7 JH |
4063 | { |
4064 | rtx sset; | |
4065 | ||
4066 | /* Check for reg or cc0 setting instructions followed by | |
4067 | conditional branch instructions first. */ | |
4068 | if (alter_jumps | |
4069 | && (sset = single_set (insn)) != NULL | |
244d05fb | 4070 | && NEXT_INSN (insn) |
ae860ff7 JH |
4071 | && any_condjump_p (NEXT_INSN (insn)) && onlyjump_p (NEXT_INSN (insn))) |
4072 | { | |
4073 | rtx dest = SET_DEST (sset); | |
4074 | if ((REG_P (dest) || CC0_P (dest)) | |
4075 | && cprop_jump (BLOCK_FOR_INSN (insn), insn, NEXT_INSN (insn), from, to)) | |
4076 | return 1; | |
4077 | } | |
4078 | ||
4079 | /* Handle normal insns next. */ | |
4080 | if (GET_CODE (insn) == INSN | |
4081 | && try_replace_reg (from, to, insn)) | |
4082 | return 1; | |
4083 | ||
4084 | /* Try to propagate a CONST_INT into a conditional jump. | |
4085 | We're pretty specific about what we will handle in this | |
4086 | code, we can extend this as necessary over time. | |
4087 | ||
4088 | Right now the insn in question must look like | |
4089 | (set (pc) (if_then_else ...)) */ | |
4090 | else if (alter_jumps && any_condjump_p (insn) && onlyjump_p (insn)) | |
4091 | return cprop_jump (BLOCK_FOR_INSN (insn), NULL, insn, from, to); | |
4092 | return 0; | |
4093 | } | |
4094 | ||
7506f491 | 4095 | /* Perform constant and copy propagation on INSN. |
cc2902df | 4096 | The result is nonzero if a change was made. */ |
7506f491 DE |
4097 | |
4098 | static int | |
1d088dee | 4099 | cprop_insn (rtx insn, int alter_jumps) |
7506f491 DE |
4100 | { |
4101 | struct reg_use *reg_used; | |
4102 | int changed = 0; | |
833fc3ad | 4103 | rtx note; |
7506f491 | 4104 | |
9e71c818 | 4105 | if (!INSN_P (insn)) |
7506f491 DE |
4106 | return 0; |
4107 | ||
4108 | reg_use_count = 0; | |
9e71c818 | 4109 | note_uses (&PATTERN (insn), find_used_regs, NULL); |
589005ff | 4110 | |
172890a2 | 4111 | note = find_reg_equal_equiv_note (insn); |
833fc3ad | 4112 | |
dc297297 | 4113 | /* We may win even when propagating constants into notes. */ |
833fc3ad | 4114 | if (note) |
9e71c818 | 4115 | find_used_regs (&XEXP (note, 0), NULL); |
7506f491 | 4116 | |
c4c81601 RK |
4117 | for (reg_used = ®_use_table[0]; reg_use_count > 0; |
4118 | reg_used++, reg_use_count--) | |
7506f491 | 4119 | { |
770ae6cc | 4120 | unsigned int regno = REGNO (reg_used->reg_rtx); |
7506f491 DE |
4121 | rtx pat, src; |
4122 | struct expr *set; | |
7506f491 DE |
4123 | |
4124 | /* Ignore registers created by GCSE. | |
dc297297 | 4125 | We do this because ... */ |
7506f491 DE |
4126 | if (regno >= max_gcse_regno) |
4127 | continue; | |
4128 | ||
4129 | /* If the register has already been set in this block, there's | |
4130 | nothing we can do. */ | |
4131 | if (! oprs_not_set_p (reg_used->reg_rtx, insn)) | |
4132 | continue; | |
4133 | ||
4134 | /* Find an assignment that sets reg_used and is available | |
4135 | at the start of the block. */ | |
4136 | set = find_avail_set (regno, insn); | |
4137 | if (! set) | |
4138 | continue; | |
589005ff | 4139 | |
7506f491 DE |
4140 | pat = set->expr; |
4141 | /* ??? We might be able to handle PARALLELs. Later. */ | |
4142 | if (GET_CODE (pat) != SET) | |
4143 | abort (); | |
c4c81601 | 4144 | |
7506f491 DE |
4145 | src = SET_SRC (pat); |
4146 | ||
e78d9500 | 4147 | /* Constant propagation. */ |
6b2d1c9e | 4148 | if (gcse_constant_p (src)) |
7506f491 | 4149 | { |
ae860ff7 | 4150 | if (constprop_register (insn, reg_used->reg_rtx, src, alter_jumps)) |
7506f491 DE |
4151 | { |
4152 | changed = 1; | |
4153 | const_prop_count++; | |
4154 | if (gcse_file != NULL) | |
4155 | { | |
ae860ff7 JH |
4156 | fprintf (gcse_file, "GLOBAL CONST-PROP: Replacing reg %d in ", regno); |
4157 | fprintf (gcse_file, "insn %d with constant ", INSN_UID (insn)); | |
e78d9500 | 4158 | print_rtl (gcse_file, src); |
7506f491 DE |
4159 | fprintf (gcse_file, "\n"); |
4160 | } | |
bc6688b4 RS |
4161 | if (INSN_DELETED_P (insn)) |
4162 | return 1; | |
7506f491 DE |
4163 | } |
4164 | } | |
4165 | else if (GET_CODE (src) == REG | |
4166 | && REGNO (src) >= FIRST_PSEUDO_REGISTER | |
4167 | && REGNO (src) != regno) | |
4168 | { | |
cafba495 | 4169 | if (try_replace_reg (reg_used->reg_rtx, src, insn)) |
7506f491 | 4170 | { |
cafba495 BS |
4171 | changed = 1; |
4172 | copy_prop_count++; | |
4173 | if (gcse_file != NULL) | |
7506f491 | 4174 | { |
ae860ff7 | 4175 | fprintf (gcse_file, "GLOBAL COPY-PROP: Replacing reg %d in insn %d", |
c4c81601 RK |
4176 | regno, INSN_UID (insn)); |
4177 | fprintf (gcse_file, " with reg %d\n", REGNO (src)); | |
7506f491 | 4178 | } |
cafba495 BS |
4179 | |
4180 | /* The original insn setting reg_used may or may not now be | |
4181 | deletable. We leave the deletion to flow. */ | |
4182 | /* FIXME: If it turns out that the insn isn't deletable, | |
4183 | then we may have unnecessarily extended register lifetimes | |
4184 | and made things worse. */ | |
7506f491 DE |
4185 | } |
4186 | } | |
4187 | } | |
4188 | ||
4189 | return changed; | |
4190 | } | |
4191 | ||
710ee3ed RH |
4192 | /* Like find_used_regs, but avoid recording uses that appear in |
4193 | input-output contexts such as zero_extract or pre_dec. This | |
4194 | restricts the cases we consider to those for which local cprop | |
4195 | can legitimately make replacements. */ | |
4196 | ||
4197 | static void | |
1d088dee | 4198 | local_cprop_find_used_regs (rtx *xptr, void *data) |
710ee3ed RH |
4199 | { |
4200 | rtx x = *xptr; | |
4201 | ||
4202 | if (x == 0) | |
4203 | return; | |
4204 | ||
4205 | switch (GET_CODE (x)) | |
4206 | { | |
4207 | case ZERO_EXTRACT: | |
4208 | case SIGN_EXTRACT: | |
4209 | case STRICT_LOW_PART: | |
4210 | return; | |
4211 | ||
4212 | case PRE_DEC: | |
4213 | case PRE_INC: | |
4214 | case POST_DEC: | |
4215 | case POST_INC: | |
4216 | case PRE_MODIFY: | |
4217 | case POST_MODIFY: | |
4218 | /* Can only legitimately appear this early in the context of | |
4219 | stack pushes for function arguments, but handle all of the | |
4220 | codes nonetheless. */ | |
4221 | return; | |
4222 | ||
4223 | case SUBREG: | |
4224 | /* Setting a subreg of a register larger than word_mode leaves | |
4225 | the non-written words unchanged. */ | |
4226 | if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) > BITS_PER_WORD) | |
4227 | return; | |
4228 | break; | |
4229 | ||
4230 | default: | |
4231 | break; | |
4232 | } | |
4233 | ||
4234 | find_used_regs (xptr, data); | |
4235 | } | |
1d088dee | 4236 | |
8ba46434 R |
4237 | /* LIBCALL_SP is a zero-terminated array of insns at the end of a libcall; |
4238 | their REG_EQUAL notes need updating. */ | |
e197b6fc | 4239 | |
ae860ff7 | 4240 | static bool |
1d088dee | 4241 | do_local_cprop (rtx x, rtx insn, int alter_jumps, rtx *libcall_sp) |
ae860ff7 JH |
4242 | { |
4243 | rtx newreg = NULL, newcnst = NULL; | |
4244 | ||
e197b6fc RH |
4245 | /* Rule out USE instructions and ASM statements as we don't want to |
4246 | change the hard registers mentioned. */ | |
ae860ff7 JH |
4247 | if (GET_CODE (x) == REG |
4248 | && (REGNO (x) >= FIRST_PSEUDO_REGISTER | |
e197b6fc RH |
4249 | || (GET_CODE (PATTERN (insn)) != USE |
4250 | && asm_noperands (PATTERN (insn)) < 0))) | |
ae860ff7 JH |
4251 | { |
4252 | cselib_val *val = cselib_lookup (x, GET_MODE (x), 0); | |
4253 | struct elt_loc_list *l; | |
4254 | ||
4255 | if (!val) | |
4256 | return false; | |
4257 | for (l = val->locs; l; l = l->next) | |
4258 | { | |
4259 | rtx this_rtx = l->loc; | |
46690369 JH |
4260 | rtx note; |
4261 | ||
9635cfad JH |
4262 | if (l->in_libcall) |
4263 | continue; | |
4264 | ||
6b2d1c9e | 4265 | if (gcse_constant_p (this_rtx)) |
ae860ff7 | 4266 | newcnst = this_rtx; |
46690369 JH |
4267 | if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER |
4268 | /* Don't copy propagate if it has attached REG_EQUIV note. | |
4269 | At this point this only function parameters should have | |
4270 | REG_EQUIV notes and if the argument slot is used somewhere | |
4271 | explicitly, it means address of parameter has been taken, | |
4272 | so we should not extend the lifetime of the pseudo. */ | |
4273 | && (!(note = find_reg_note (l->setting_insn, REG_EQUIV, NULL_RTX)) | |
4274 | || GET_CODE (XEXP (note, 0)) != MEM)) | |
ae860ff7 JH |
4275 | newreg = this_rtx; |
4276 | } | |
4277 | if (newcnst && constprop_register (insn, x, newcnst, alter_jumps)) | |
4278 | { | |
8ba46434 | 4279 | /* If we find a case where we can't fix the retval REG_EQUAL notes |
fbe5a4a6 | 4280 | match the new register, we either have to abandon this replacement |
8ba46434 R |
4281 | or fix delete_trivially_dead_insns to preserve the setting insn, |
4282 | or make it delete the REG_EUAQL note, and fix up all passes that | |
4283 | require the REG_EQUAL note there. */ | |
4284 | if (!adjust_libcall_notes (x, newcnst, insn, libcall_sp)) | |
4285 | abort (); | |
ae860ff7 JH |
4286 | if (gcse_file != NULL) |
4287 | { | |
4288 | fprintf (gcse_file, "LOCAL CONST-PROP: Replacing reg %d in ", | |
4289 | REGNO (x)); | |
4290 | fprintf (gcse_file, "insn %d with constant ", | |
4291 | INSN_UID (insn)); | |
4292 | print_rtl (gcse_file, newcnst); | |
4293 | fprintf (gcse_file, "\n"); | |
4294 | } | |
4295 | const_prop_count++; | |
4296 | return true; | |
4297 | } | |
4298 | else if (newreg && newreg != x && try_replace_reg (x, newreg, insn)) | |
4299 | { | |
8ba46434 | 4300 | adjust_libcall_notes (x, newreg, insn, libcall_sp); |
ae860ff7 JH |
4301 | if (gcse_file != NULL) |
4302 | { | |
4303 | fprintf (gcse_file, | |
4304 | "LOCAL COPY-PROP: Replacing reg %d in insn %d", | |
4305 | REGNO (x), INSN_UID (insn)); | |
4306 | fprintf (gcse_file, " with reg %d\n", REGNO (newreg)); | |
4307 | } | |
4308 | copy_prop_count++; | |
4309 | return true; | |
4310 | } | |
4311 | } | |
4312 | return false; | |
4313 | } | |
4314 | ||
8ba46434 R |
4315 | /* LIBCALL_SP is a zero-terminated array of insns at the end of a libcall; |
4316 | their REG_EQUAL notes need updating to reflect that OLDREG has been | |
f4e3e618 RH |
4317 | replaced with NEWVAL in INSN. Return true if all substitutions could |
4318 | be made. */ | |
8ba46434 | 4319 | static bool |
1d088dee | 4320 | adjust_libcall_notes (rtx oldreg, rtx newval, rtx insn, rtx *libcall_sp) |
8ba46434 | 4321 | { |
f4e3e618 | 4322 | rtx end; |
8ba46434 R |
4323 | |
4324 | while ((end = *libcall_sp++)) | |
4325 | { | |
f4e3e618 | 4326 | rtx note = find_reg_equal_equiv_note (end); |
8ba46434 R |
4327 | |
4328 | if (! note) | |
4329 | continue; | |
4330 | ||
4331 | if (REG_P (newval)) | |
4332 | { | |
4333 | if (reg_set_between_p (newval, PREV_INSN (insn), end)) | |
4334 | { | |
4335 | do | |
4336 | { | |
4337 | note = find_reg_equal_equiv_note (end); | |
4338 | if (! note) | |
4339 | continue; | |
4340 | if (reg_mentioned_p (newval, XEXP (note, 0))) | |
4341 | return false; | |
4342 | } | |
4343 | while ((end = *libcall_sp++)); | |
4344 | return true; | |
4345 | } | |
4346 | } | |
4347 | XEXP (note, 0) = replace_rtx (XEXP (note, 0), oldreg, newval); | |
4348 | insn = end; | |
4349 | } | |
4350 | return true; | |
4351 | } | |
4352 | ||
4353 | #define MAX_NESTED_LIBCALLS 9 | |
4354 | ||
ae860ff7 | 4355 | static void |
1d088dee | 4356 | local_cprop_pass (int alter_jumps) |
ae860ff7 JH |
4357 | { |
4358 | rtx insn; | |
4359 | struct reg_use *reg_used; | |
8ba46434 | 4360 | rtx libcall_stack[MAX_NESTED_LIBCALLS + 1], *libcall_sp; |
1649d92f | 4361 | bool changed = false; |
ae860ff7 JH |
4362 | |
4363 | cselib_init (); | |
8ba46434 R |
4364 | libcall_sp = &libcall_stack[MAX_NESTED_LIBCALLS]; |
4365 | *libcall_sp = 0; | |
ae860ff7 JH |
4366 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
4367 | { | |
4368 | if (INSN_P (insn)) | |
4369 | { | |
8ba46434 | 4370 | rtx note = find_reg_note (insn, REG_LIBCALL, NULL_RTX); |
ae860ff7 | 4371 | |
8ba46434 R |
4372 | if (note) |
4373 | { | |
4374 | if (libcall_sp == libcall_stack) | |
4375 | abort (); | |
4376 | *--libcall_sp = XEXP (note, 0); | |
4377 | } | |
4378 | note = find_reg_note (insn, REG_RETVAL, NULL_RTX); | |
4379 | if (note) | |
4380 | libcall_sp++; | |
4381 | note = find_reg_equal_equiv_note (insn); | |
ae860ff7 JH |
4382 | do |
4383 | { | |
4384 | reg_use_count = 0; | |
710ee3ed | 4385 | note_uses (&PATTERN (insn), local_cprop_find_used_regs, NULL); |
ae860ff7 | 4386 | if (note) |
710ee3ed | 4387 | local_cprop_find_used_regs (&XEXP (note, 0), NULL); |
ae860ff7 JH |
4388 | |
4389 | for (reg_used = ®_use_table[0]; reg_use_count > 0; | |
4390 | reg_used++, reg_use_count--) | |
8ba46434 R |
4391 | if (do_local_cprop (reg_used->reg_rtx, insn, alter_jumps, |
4392 | libcall_sp)) | |
1649d92f JH |
4393 | { |
4394 | changed = true; | |
4395 | break; | |
4396 | } | |
bc6688b4 RS |
4397 | if (INSN_DELETED_P (insn)) |
4398 | break; | |
ae860ff7 JH |
4399 | } |
4400 | while (reg_use_count); | |
4401 | } | |
4402 | cselib_process_insn (insn); | |
4403 | } | |
4404 | cselib_finish (); | |
1649d92f JH |
4405 | /* Global analysis may get into infinite loops for unreachable blocks. */ |
4406 | if (changed && alter_jumps) | |
5f0bea72 JH |
4407 | { |
4408 | delete_unreachable_blocks (); | |
4409 | free_reg_set_mem (); | |
4410 | alloc_reg_set_mem (max_reg_num ()); | |
4411 | compute_sets (get_insns ()); | |
4412 | } | |
ae860ff7 JH |
4413 | } |
4414 | ||
c4c81601 | 4415 | /* Forward propagate copies. This includes copies and constants. Return |
cc2902df | 4416 | nonzero if a change was made. */ |
7506f491 DE |
4417 | |
4418 | static int | |
1d088dee | 4419 | cprop (int alter_jumps) |
7506f491 | 4420 | { |
e0082a72 ZD |
4421 | int changed; |
4422 | basic_block bb; | |
7506f491 DE |
4423 | rtx insn; |
4424 | ||
4425 | /* Note we start at block 1. */ | |
e0082a72 ZD |
4426 | if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR) |
4427 | { | |
4428 | if (gcse_file != NULL) | |
4429 | fprintf (gcse_file, "\n"); | |
4430 | return 0; | |
4431 | } | |
7506f491 DE |
4432 | |
4433 | changed = 0; | |
e0082a72 | 4434 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, EXIT_BLOCK_PTR, next_bb) |
7506f491 DE |
4435 | { |
4436 | /* Reset tables used to keep track of what's still valid [since the | |
4437 | start of the block]. */ | |
4438 | reset_opr_set_tables (); | |
4439 | ||
e0082a72 ZD |
4440 | for (insn = bb->head; |
4441 | insn != NULL && insn != NEXT_INSN (bb->end); | |
7506f491 | 4442 | insn = NEXT_INSN (insn)) |
172890a2 RK |
4443 | if (INSN_P (insn)) |
4444 | { | |
ae860ff7 | 4445 | changed |= cprop_insn (insn, alter_jumps); |
7506f491 | 4446 | |
172890a2 RK |
4447 | /* Keep track of everything modified by this insn. */ |
4448 | /* ??? Need to be careful w.r.t. mods done to INSN. Don't | |
4449 | call mark_oprs_set if we turned the insn into a NOTE. */ | |
4450 | if (GET_CODE (insn) != NOTE) | |
4451 | mark_oprs_set (insn); | |
8e42ace1 | 4452 | } |
7506f491 DE |
4453 | } |
4454 | ||
4455 | if (gcse_file != NULL) | |
4456 | fprintf (gcse_file, "\n"); | |
4457 | ||
4458 | return changed; | |
4459 | } | |
4460 | ||
fbef91d8 RS |
4461 | /* Similar to get_condition, only the resulting condition must be |
4462 | valid at JUMP, instead of at EARLIEST. | |
4463 | ||
4464 | This differs from noce_get_condition in ifcvt.c in that we prefer not to | |
4465 | settle for the condition variable in the jump instruction being integral. | |
4466 | We prefer to be able to record the value of a user variable, rather than | |
4467 | the value of a temporary used in a condition. This could be solved by | |
4468 | recording the value of *every* register scaned by canonicalize_condition, | |
4469 | but this would require some code reorganization. */ | |
4470 | ||
2fa4a849 | 4471 | rtx |
1d088dee | 4472 | fis_get_condition (rtx jump) |
fbef91d8 RS |
4473 | { |
4474 | rtx cond, set, tmp, insn, earliest; | |
4475 | bool reverse; | |
4476 | ||
4477 | if (! any_condjump_p (jump)) | |
4478 | return NULL_RTX; | |
4479 | ||
4480 | set = pc_set (jump); | |
4481 | cond = XEXP (SET_SRC (set), 0); | |
4482 | ||
4483 | /* If this branches to JUMP_LABEL when the condition is false, | |
4484 | reverse the condition. */ | |
4485 | reverse = (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF | |
4486 | && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump)); | |
4487 | ||
4488 | /* Use canonicalize_condition to do the dirty work of manipulating | |
4489 | MODE_CC values and COMPARE rtx codes. */ | |
4490 | tmp = canonicalize_condition (jump, cond, reverse, &earliest, NULL_RTX); | |
4491 | if (!tmp) | |
4492 | return NULL_RTX; | |
4493 | ||
4494 | /* Verify that the given condition is valid at JUMP by virtue of not | |
4495 | having been modified since EARLIEST. */ | |
4496 | for (insn = earliest; insn != jump; insn = NEXT_INSN (insn)) | |
4497 | if (INSN_P (insn) && modified_in_p (tmp, insn)) | |
4498 | break; | |
4499 | if (insn == jump) | |
4500 | return tmp; | |
4501 | ||
4502 | /* The condition was modified. See if we can get a partial result | |
4503 | that doesn't follow all the reversals. Perhaps combine can fold | |
4504 | them together later. */ | |
4505 | tmp = XEXP (tmp, 0); | |
4506 | if (!REG_P (tmp) || GET_MODE_CLASS (GET_MODE (tmp)) != MODE_INT) | |
4507 | return NULL_RTX; | |
4508 | tmp = canonicalize_condition (jump, cond, reverse, &earliest, tmp); | |
4509 | if (!tmp) | |
4510 | return NULL_RTX; | |
4511 | ||
4512 | /* For sanity's sake, re-validate the new result. */ | |
4513 | for (insn = earliest; insn != jump; insn = NEXT_INSN (insn)) | |
4514 | if (INSN_P (insn) && modified_in_p (tmp, insn)) | |
4515 | return NULL_RTX; | |
4516 | ||
4517 | return tmp; | |
4518 | } | |
4519 | ||
4520 | /* Find the implicit sets of a function. An "implicit set" is a constraint | |
4521 | on the value of a variable, implied by a conditional jump. For example, | |
4522 | following "if (x == 2)", the then branch may be optimized as though the | |
4523 | conditional performed an "explicit set", in this example, "x = 2". This | |
4524 | function records the set patterns that are implicit at the start of each | |
4525 | basic block. */ | |
4526 | ||
4527 | static void | |
1d088dee | 4528 | find_implicit_sets (void) |
fbef91d8 RS |
4529 | { |
4530 | basic_block bb, dest; | |
4531 | unsigned int count; | |
4532 | rtx cond, new; | |
4533 | ||
4534 | count = 0; | |
4535 | FOR_EACH_BB (bb) | |
4536 | /* Check for more than one sucessor. */ | |
4537 | if (bb->succ && bb->succ->succ_next) | |
4538 | { | |
4539 | cond = fis_get_condition (bb->end); | |
4540 | ||
4541 | if (cond | |
4542 | && (GET_CODE (cond) == EQ || GET_CODE (cond) == NE) | |
4543 | && GET_CODE (XEXP (cond, 0)) == REG | |
4544 | && REGNO (XEXP (cond, 0)) >= FIRST_PSEUDO_REGISTER | |
6b2d1c9e | 4545 | && gcse_constant_p (XEXP (cond, 1))) |
fbef91d8 RS |
4546 | { |
4547 | dest = GET_CODE (cond) == EQ ? BRANCH_EDGE (bb)->dest | |
4548 | : FALLTHRU_EDGE (bb)->dest; | |
4549 | ||
4550 | if (dest && ! dest->pred->pred_next | |
4551 | && dest != EXIT_BLOCK_PTR) | |
4552 | { | |
4553 | new = gen_rtx_SET (VOIDmode, XEXP (cond, 0), | |
4554 | XEXP (cond, 1)); | |
4555 | implicit_sets[dest->index] = new; | |
4556 | if (gcse_file) | |
4557 | { | |
4558 | fprintf(gcse_file, "Implicit set of reg %d in ", | |
4559 | REGNO (XEXP (cond, 0))); | |
4560 | fprintf(gcse_file, "basic block %d\n", dest->index); | |
4561 | } | |
4562 | count++; | |
4563 | } | |
4564 | } | |
4565 | } | |
4566 | ||
4567 | if (gcse_file) | |
4568 | fprintf (gcse_file, "Found %d implicit sets\n", count); | |
4569 | } | |
4570 | ||
7506f491 | 4571 | /* Perform one copy/constant propagation pass. |
a0134312 RS |
4572 | PASS is the pass count. If CPROP_JUMPS is true, perform constant |
4573 | propagation into conditional jumps. If BYPASS_JUMPS is true, | |
4574 | perform conditional jump bypassing optimizations. */ | |
7506f491 DE |
4575 | |
4576 | static int | |
1d088dee | 4577 | one_cprop_pass (int pass, int cprop_jumps, int bypass_jumps) |
7506f491 DE |
4578 | { |
4579 | int changed = 0; | |
4580 | ||
4581 | const_prop_count = 0; | |
4582 | copy_prop_count = 0; | |
4583 | ||
a0134312 | 4584 | local_cprop_pass (cprop_jumps); |
ae860ff7 | 4585 | |
fbef91d8 | 4586 | /* Determine implicit sets. */ |
703ad42b | 4587 | implicit_sets = xcalloc (last_basic_block, sizeof (rtx)); |
fbef91d8 RS |
4588 | find_implicit_sets (); |
4589 | ||
02280659 ZD |
4590 | alloc_hash_table (max_cuid, &set_hash_table, 1); |
4591 | compute_hash_table (&set_hash_table); | |
fbef91d8 RS |
4592 | |
4593 | /* Free implicit_sets before peak usage. */ | |
4594 | free (implicit_sets); | |
4595 | implicit_sets = NULL; | |
4596 | ||
7506f491 | 4597 | if (gcse_file) |
02280659 ZD |
4598 | dump_hash_table (gcse_file, "SET", &set_hash_table); |
4599 | if (set_hash_table.n_elems > 0) | |
7506f491 | 4600 | { |
02280659 | 4601 | alloc_cprop_mem (last_basic_block, set_hash_table.n_elems); |
7506f491 | 4602 | compute_cprop_data (); |
a0134312 RS |
4603 | changed = cprop (cprop_jumps); |
4604 | if (bypass_jumps) | |
0e3f0221 | 4605 | changed |= bypass_conditional_jumps (); |
7506f491 DE |
4606 | free_cprop_mem (); |
4607 | } | |
c4c81601 | 4608 | |
02280659 | 4609 | free_hash_table (&set_hash_table); |
7506f491 DE |
4610 | |
4611 | if (gcse_file) | |
4612 | { | |
c4c81601 RK |
4613 | fprintf (gcse_file, "CPROP of %s, pass %d: %d bytes needed, ", |
4614 | current_function_name, pass, bytes_used); | |
4615 | fprintf (gcse_file, "%d const props, %d copy props\n\n", | |
4616 | const_prop_count, copy_prop_count); | |
7506f491 | 4617 | } |
1649d92f JH |
4618 | /* Global analysis may get into infinite loops for unreachable blocks. */ |
4619 | if (changed && cprop_jumps) | |
4620 | delete_unreachable_blocks (); | |
7506f491 DE |
4621 | |
4622 | return changed; | |
4623 | } | |
4624 | \f | |
0e3f0221 RS |
4625 | /* Bypass conditional jumps. */ |
4626 | ||
7821bfc7 RS |
4627 | /* The value of last_basic_block at the beginning of the jump_bypass |
4628 | pass. The use of redirect_edge_and_branch_force may introduce new | |
4629 | basic blocks, but the data flow analysis is only valid for basic | |
4630 | block indices less than bypass_last_basic_block. */ | |
4631 | ||
4632 | static int bypass_last_basic_block; | |
4633 | ||
0e3f0221 RS |
4634 | /* Find a set of REGNO to a constant that is available at the end of basic |
4635 | block BB. Returns NULL if no such set is found. Based heavily upon | |
4636 | find_avail_set. */ | |
4637 | ||
4638 | static struct expr * | |
1d088dee | 4639 | find_bypass_set (int regno, int bb) |
0e3f0221 RS |
4640 | { |
4641 | struct expr *result = 0; | |
4642 | ||
4643 | for (;;) | |
4644 | { | |
4645 | rtx src; | |
ceda50e9 | 4646 | struct expr *set = lookup_set (regno, &set_hash_table); |
0e3f0221 RS |
4647 | |
4648 | while (set) | |
4649 | { | |
4650 | if (TEST_BIT (cprop_avout[bb], set->bitmap_index)) | |
4651 | break; | |
4652 | set = next_set (regno, set); | |
4653 | } | |
4654 | ||
4655 | if (set == 0) | |
4656 | break; | |
4657 | ||
4658 | if (GET_CODE (set->expr) != SET) | |
4659 | abort (); | |
4660 | ||
4661 | src = SET_SRC (set->expr); | |
6b2d1c9e | 4662 | if (gcse_constant_p (src)) |
0e3f0221 RS |
4663 | result = set; |
4664 | ||
4665 | if (GET_CODE (src) != REG) | |
4666 | break; | |
4667 | ||
4668 | regno = REGNO (src); | |
4669 | } | |
4670 | return result; | |
4671 | } | |
4672 | ||
4673 | ||
e129b3f9 RS |
4674 | /* Subroutine of bypass_block that checks whether a pseudo is killed by |
4675 | any of the instructions inserted on an edge. Jump bypassing places | |
4676 | condition code setters on CFG edges using insert_insn_on_edge. This | |
4677 | function is required to check that our data flow analysis is still | |
4678 | valid prior to commit_edge_insertions. */ | |
4679 | ||
4680 | static bool | |
1d088dee | 4681 | reg_killed_on_edge (rtx reg, edge e) |
e129b3f9 RS |
4682 | { |
4683 | rtx insn; | |
4684 | ||
4685 | for (insn = e->insns; insn; insn = NEXT_INSN (insn)) | |
4686 | if (INSN_P (insn) && reg_set_p (reg, insn)) | |
4687 | return true; | |
4688 | ||
4689 | return false; | |
4690 | } | |
4691 | ||
0e3f0221 RS |
4692 | /* Subroutine of bypass_conditional_jumps that attempts to bypass the given |
4693 | basic block BB which has more than one predecessor. If not NULL, SETCC | |
4694 | is the first instruction of BB, which is immediately followed by JUMP_INSN | |
4695 | JUMP. Otherwise, SETCC is NULL, and JUMP is the first insn of BB. | |
e129b3f9 RS |
4696 | Returns nonzero if a change was made. |
4697 | ||
e0bb17a8 | 4698 | During the jump bypassing pass, we may place copies of SETCC instructions |
e129b3f9 RS |
4699 | on CFG edges. The following routine must be careful to pay attention to |
4700 | these inserted insns when performing its transformations. */ | |
0e3f0221 RS |
4701 | |
4702 | static int | |
1d088dee | 4703 | bypass_block (basic_block bb, rtx setcc, rtx jump) |
0e3f0221 RS |
4704 | { |
4705 | rtx insn, note; | |
e129b3f9 | 4706 | edge e, enext, edest; |
818b6b7f | 4707 | int i, change; |
72b8d451 | 4708 | int may_be_loop_header; |
0e3f0221 RS |
4709 | |
4710 | insn = (setcc != NULL) ? setcc : jump; | |
4711 | ||
4712 | /* Determine set of register uses in INSN. */ | |
4713 | reg_use_count = 0; | |
4714 | note_uses (&PATTERN (insn), find_used_regs, NULL); | |
4715 | note = find_reg_equal_equiv_note (insn); | |
4716 | if (note) | |
4717 | find_used_regs (&XEXP (note, 0), NULL); | |
4718 | ||
72b8d451 ZD |
4719 | may_be_loop_header = false; |
4720 | for (e = bb->pred; e; e = e->pred_next) | |
4721 | if (e->flags & EDGE_DFS_BACK) | |
4722 | { | |
4723 | may_be_loop_header = true; | |
4724 | break; | |
4725 | } | |
4726 | ||
0e3f0221 RS |
4727 | change = 0; |
4728 | for (e = bb->pred; e; e = enext) | |
4729 | { | |
4730 | enext = e->pred_next; | |
7821bfc7 RS |
4731 | if (e->flags & EDGE_COMPLEX) |
4732 | continue; | |
4733 | ||
4734 | /* We can't redirect edges from new basic blocks. */ | |
4735 | if (e->src->index >= bypass_last_basic_block) | |
4736 | continue; | |
4737 | ||
72b8d451 | 4738 | /* The irreducible loops created by redirecting of edges entering the |
e0bb17a8 KH |
4739 | loop from outside would decrease effectiveness of some of the following |
4740 | optimizations, so prevent this. */ | |
72b8d451 ZD |
4741 | if (may_be_loop_header |
4742 | && !(e->flags & EDGE_DFS_BACK)) | |
4743 | continue; | |
4744 | ||
0e3f0221 RS |
4745 | for (i = 0; i < reg_use_count; i++) |
4746 | { | |
4747 | struct reg_use *reg_used = ®_use_table[i]; | |
589005ff | 4748 | unsigned int regno = REGNO (reg_used->reg_rtx); |
818b6b7f | 4749 | basic_block dest, old_dest; |
589005ff KH |
4750 | struct expr *set; |
4751 | rtx src, new; | |
0e3f0221 | 4752 | |
589005ff KH |
4753 | if (regno >= max_gcse_regno) |
4754 | continue; | |
0e3f0221 | 4755 | |
589005ff | 4756 | set = find_bypass_set (regno, e->src->index); |
0e3f0221 RS |
4757 | |
4758 | if (! set) | |
4759 | continue; | |
4760 | ||
e129b3f9 RS |
4761 | /* Check the data flow is valid after edge insertions. */ |
4762 | if (e->insns && reg_killed_on_edge (reg_used->reg_rtx, e)) | |
4763 | continue; | |
4764 | ||
589005ff | 4765 | src = SET_SRC (pc_set (jump)); |
0e3f0221 RS |
4766 | |
4767 | if (setcc != NULL) | |
4768 | src = simplify_replace_rtx (src, | |
589005ff KH |
4769 | SET_DEST (PATTERN (setcc)), |
4770 | SET_SRC (PATTERN (setcc))); | |
0e3f0221 RS |
4771 | |
4772 | new = simplify_replace_rtx (src, reg_used->reg_rtx, | |
589005ff | 4773 | SET_SRC (set->expr)); |
0e3f0221 | 4774 | |
1d088dee | 4775 | /* Jump bypassing may have already placed instructions on |
e129b3f9 RS |
4776 | edges of the CFG. We can't bypass an outgoing edge that |
4777 | has instructions associated with it, as these insns won't | |
4778 | get executed if the incoming edge is redirected. */ | |
4779 | ||
589005ff | 4780 | if (new == pc_rtx) |
e129b3f9 RS |
4781 | { |
4782 | edest = FALLTHRU_EDGE (bb); | |
4783 | dest = edest->insns ? NULL : edest->dest; | |
4784 | } | |
0e3f0221 | 4785 | else if (GET_CODE (new) == LABEL_REF) |
e129b3f9 RS |
4786 | { |
4787 | dest = BLOCK_FOR_INSN (XEXP (new, 0)); | |
4788 | /* Don't bypass edges containing instructions. */ | |
4789 | for (edest = bb->succ; edest; edest = edest->succ_next) | |
4790 | if (edest->dest == dest && edest->insns) | |
4791 | { | |
4792 | dest = NULL; | |
4793 | break; | |
4794 | } | |
4795 | } | |
0e3f0221 RS |
4796 | else |
4797 | dest = NULL; | |
4798 | ||
818b6b7f | 4799 | old_dest = e->dest; |
7821bfc7 RS |
4800 | if (dest != NULL |
4801 | && dest != old_dest | |
4802 | && dest != EXIT_BLOCK_PTR) | |
4803 | { | |
4804 | redirect_edge_and_branch_force (e, dest); | |
4805 | ||
818b6b7f | 4806 | /* Copy the register setter to the redirected edge. |
0e3f0221 RS |
4807 | Don't copy CC0 setters, as CC0 is dead after jump. */ |
4808 | if (setcc) | |
4809 | { | |
4810 | rtx pat = PATTERN (setcc); | |
818b6b7f | 4811 | if (!CC0_P (SET_DEST (pat))) |
0e3f0221 RS |
4812 | insert_insn_on_edge (copy_insn (pat), e); |
4813 | } | |
4814 | ||
4815 | if (gcse_file != NULL) | |
4816 | { | |
818b6b7f RH |
4817 | fprintf (gcse_file, "JUMP-BYPASS: Proved reg %d in jump_insn %d equals constant ", |
4818 | regno, INSN_UID (jump)); | |
0e3f0221 RS |
4819 | print_rtl (gcse_file, SET_SRC (set->expr)); |
4820 | fprintf (gcse_file, "\nBypass edge from %d->%d to %d\n", | |
818b6b7f | 4821 | e->src->index, old_dest->index, dest->index); |
0e3f0221 RS |
4822 | } |
4823 | change = 1; | |
4824 | break; | |
4825 | } | |
4826 | } | |
4827 | } | |
4828 | return change; | |
4829 | } | |
4830 | ||
4831 | /* Find basic blocks with more than one predecessor that only contain a | |
4832 | single conditional jump. If the result of the comparison is known at | |
4833 | compile-time from any incoming edge, redirect that edge to the | |
9a71ece1 RH |
4834 | appropriate target. Returns nonzero if a change was made. |
4835 | ||
4836 | This function is now mis-named, because we also handle indirect jumps. */ | |
0e3f0221 RS |
4837 | |
4838 | static int | |
1d088dee | 4839 | bypass_conditional_jumps (void) |
0e3f0221 RS |
4840 | { |
4841 | basic_block bb; | |
4842 | int changed; | |
4843 | rtx setcc; | |
4844 | rtx insn; | |
4845 | rtx dest; | |
4846 | ||
4847 | /* Note we start at block 1. */ | |
4848 | if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR) | |
4849 | return 0; | |
4850 | ||
7821bfc7 | 4851 | bypass_last_basic_block = last_basic_block; |
72b8d451 | 4852 | mark_dfs_back_edges (); |
7821bfc7 | 4853 | |
0e3f0221 RS |
4854 | changed = 0; |
4855 | FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, | |
589005ff | 4856 | EXIT_BLOCK_PTR, next_bb) |
0e3f0221 RS |
4857 | { |
4858 | /* Check for more than one predecessor. */ | |
4859 | if (bb->pred && bb->pred->pred_next) | |
4860 | { | |
4861 | setcc = NULL_RTX; | |
4862 | for (insn = bb->head; | |
4863 | insn != NULL && insn != NEXT_INSN (bb->end); | |
4864 | insn = NEXT_INSN (insn)) | |
4865 | if (GET_CODE (insn) == INSN) | |
4866 | { | |
9543a9d2 | 4867 | if (setcc) |
0e3f0221 | 4868 | break; |
ba4f7968 | 4869 | if (GET_CODE (PATTERN (insn)) != SET) |
0e3f0221 RS |
4870 | break; |
4871 | ||
ba4f7968 | 4872 | dest = SET_DEST (PATTERN (insn)); |
818b6b7f | 4873 | if (REG_P (dest) || CC0_P (dest)) |
0e3f0221 | 4874 | setcc = insn; |
0e3f0221 RS |
4875 | else |
4876 | break; | |
4877 | } | |
4878 | else if (GET_CODE (insn) == JUMP_INSN) | |
4879 | { | |
9a71ece1 RH |
4880 | if ((any_condjump_p (insn) || computed_jump_p (insn)) |
4881 | && onlyjump_p (insn)) | |
0e3f0221 RS |
4882 | changed |= bypass_block (bb, setcc, insn); |
4883 | break; | |
4884 | } | |
4885 | else if (INSN_P (insn)) | |
4886 | break; | |
4887 | } | |
4888 | } | |
4889 | ||
818b6b7f | 4890 | /* If we bypassed any register setting insns, we inserted a |
fbe5a4a6 | 4891 | copy on the redirected edge. These need to be committed. */ |
0e3f0221 RS |
4892 | if (changed) |
4893 | commit_edge_insertions(); | |
4894 | ||
4895 | return changed; | |
4896 | } | |
4897 | \f | |
a65f3558 | 4898 | /* Compute PRE+LCM working variables. */ |
7506f491 DE |
4899 | |
4900 | /* Local properties of expressions. */ | |
4901 | /* Nonzero for expressions that are transparent in the block. */ | |
a65f3558 | 4902 | static sbitmap *transp; |
7506f491 | 4903 | |
5c35539b RH |
4904 | /* Nonzero for expressions that are transparent at the end of the block. |
4905 | This is only zero for expressions killed by abnormal critical edge | |
4906 | created by a calls. */ | |
a65f3558 | 4907 | static sbitmap *transpout; |
5c35539b | 4908 | |
a65f3558 JL |
4909 | /* Nonzero for expressions that are computed (available) in the block. */ |
4910 | static sbitmap *comp; | |
7506f491 | 4911 | |
a65f3558 JL |
4912 | /* Nonzero for expressions that are locally anticipatable in the block. */ |
4913 | static sbitmap *antloc; | |
7506f491 | 4914 | |
a65f3558 JL |
4915 | /* Nonzero for expressions where this block is an optimal computation |
4916 | point. */ | |
4917 | static sbitmap *pre_optimal; | |
5c35539b | 4918 | |
a65f3558 JL |
4919 | /* Nonzero for expressions which are redundant in a particular block. */ |
4920 | static sbitmap *pre_redundant; | |
7506f491 | 4921 | |
a42cd965 AM |
4922 | /* Nonzero for expressions which should be inserted on a specific edge. */ |
4923 | static sbitmap *pre_insert_map; | |
4924 | ||
4925 | /* Nonzero for expressions which should be deleted in a specific block. */ | |
4926 | static sbitmap *pre_delete_map; | |
4927 | ||
4928 | /* Contains the edge_list returned by pre_edge_lcm. */ | |
4929 | static struct edge_list *edge_list; | |
4930 | ||
a65f3558 JL |
4931 | /* Redundant insns. */ |
4932 | static sbitmap pre_redundant_insns; | |
7506f491 | 4933 | |
a65f3558 | 4934 | /* Allocate vars used for PRE analysis. */ |
7506f491 DE |
4935 | |
4936 | static void | |
1d088dee | 4937 | alloc_pre_mem (int n_blocks, int n_exprs) |
7506f491 | 4938 | { |
a65f3558 JL |
4939 | transp = sbitmap_vector_alloc (n_blocks, n_exprs); |
4940 | comp = sbitmap_vector_alloc (n_blocks, n_exprs); | |
4941 | antloc = sbitmap_vector_alloc (n_blocks, n_exprs); | |
5faf03ae | 4942 | |
a42cd965 AM |
4943 | pre_optimal = NULL; |
4944 | pre_redundant = NULL; | |
4945 | pre_insert_map = NULL; | |
4946 | pre_delete_map = NULL; | |
4947 | ae_in = NULL; | |
4948 | ae_out = NULL; | |
a42cd965 | 4949 | ae_kill = sbitmap_vector_alloc (n_blocks, n_exprs); |
c4c81601 | 4950 | |
a42cd965 | 4951 | /* pre_insert and pre_delete are allocated later. */ |
7506f491 DE |
4952 | } |
4953 | ||
a65f3558 | 4954 | /* Free vars used for PRE analysis. */ |
7506f491 DE |
4955 | |
4956 | static void | |
1d088dee | 4957 | free_pre_mem (void) |
7506f491 | 4958 | { |
5a660bff DB |
4959 | sbitmap_vector_free (transp); |
4960 | sbitmap_vector_free (comp); | |
bd3675fc JL |
4961 | |
4962 | /* ANTLOC and AE_KILL are freed just after pre_lcm finishes. */ | |
7506f491 | 4963 | |
a42cd965 | 4964 | if (pre_optimal) |
5a660bff | 4965 | sbitmap_vector_free (pre_optimal); |
a42cd965 | 4966 | if (pre_redundant) |
5a660bff | 4967 | sbitmap_vector_free (pre_redundant); |
a42cd965 | 4968 | if (pre_insert_map) |
5a660bff | 4969 | sbitmap_vector_free (pre_insert_map); |
a42cd965 | 4970 | if (pre_delete_map) |
5a660bff | 4971 | sbitmap_vector_free (pre_delete_map); |
a42cd965 | 4972 | if (ae_in) |
5a660bff | 4973 | sbitmap_vector_free (ae_in); |
a42cd965 | 4974 | if (ae_out) |
5a660bff | 4975 | sbitmap_vector_free (ae_out); |
a42cd965 | 4976 | |
bd3675fc | 4977 | transp = comp = NULL; |
a42cd965 | 4978 | pre_optimal = pre_redundant = pre_insert_map = pre_delete_map = NULL; |
55d3f917 | 4979 | ae_in = ae_out = NULL; |
7506f491 DE |
4980 | } |
4981 | ||
4982 | /* Top level routine to do the dataflow analysis needed by PRE. */ | |
4983 | ||
4984 | static void | |
1d088dee | 4985 | compute_pre_data (void) |
7506f491 | 4986 | { |
b614171e | 4987 | sbitmap trapping_expr; |
e0082a72 | 4988 | basic_block bb; |
b614171e | 4989 | unsigned int ui; |
c66e8ae9 | 4990 | |
02280659 | 4991 | compute_local_properties (transp, comp, antloc, &expr_hash_table); |
d55bc081 | 4992 | sbitmap_vector_zero (ae_kill, last_basic_block); |
c66e8ae9 | 4993 | |
b614171e | 4994 | /* Collect expressions which might trap. */ |
02280659 | 4995 | trapping_expr = sbitmap_alloc (expr_hash_table.n_elems); |
b614171e | 4996 | sbitmap_zero (trapping_expr); |
02280659 | 4997 | for (ui = 0; ui < expr_hash_table.size; ui++) |
b614171e MM |
4998 | { |
4999 | struct expr *e; | |
02280659 | 5000 | for (e = expr_hash_table.table[ui]; e != NULL; e = e->next_same_hash) |
b614171e MM |
5001 | if (may_trap_p (e->expr)) |
5002 | SET_BIT (trapping_expr, e->bitmap_index); | |
5003 | } | |
5004 | ||
c66e8ae9 JL |
5005 | /* Compute ae_kill for each basic block using: |
5006 | ||
5007 | ~(TRANSP | COMP) | |
5008 | ||
a2e90653 | 5009 | This is significantly faster than compute_ae_kill. */ |
c66e8ae9 | 5010 | |
e0082a72 | 5011 | FOR_EACH_BB (bb) |
c66e8ae9 | 5012 | { |
b614171e MM |
5013 | edge e; |
5014 | ||
5015 | /* If the current block is the destination of an abnormal edge, we | |
5016 | kill all trapping expressions because we won't be able to properly | |
5017 | place the instruction on the edge. So make them neither | |
5018 | anticipatable nor transparent. This is fairly conservative. */ | |
e0082a72 | 5019 | for (e = bb->pred; e ; e = e->pred_next) |
b614171e MM |
5020 | if (e->flags & EDGE_ABNORMAL) |
5021 | { | |
e0082a72 ZD |
5022 | sbitmap_difference (antloc[bb->index], antloc[bb->index], trapping_expr); |
5023 | sbitmap_difference (transp[bb->index], transp[bb->index], trapping_expr); | |
b614171e MM |
5024 | break; |
5025 | } | |
5026 | ||
e0082a72 ZD |
5027 | sbitmap_a_or_b (ae_kill[bb->index], transp[bb->index], comp[bb->index]); |
5028 | sbitmap_not (ae_kill[bb->index], ae_kill[bb->index]); | |
c66e8ae9 JL |
5029 | } |
5030 | ||
02280659 | 5031 | edge_list = pre_edge_lcm (gcse_file, expr_hash_table.n_elems, transp, comp, antloc, |
a42cd965 | 5032 | ae_kill, &pre_insert_map, &pre_delete_map); |
5a660bff | 5033 | sbitmap_vector_free (antloc); |
bd3675fc | 5034 | antloc = NULL; |
5a660bff | 5035 | sbitmap_vector_free (ae_kill); |
589005ff | 5036 | ae_kill = NULL; |
76ac938b | 5037 | sbitmap_free (trapping_expr); |
7506f491 DE |
5038 | } |
5039 | \f | |
5040 | /* PRE utilities */ | |
5041 | ||
cc2902df | 5042 | /* Return nonzero if an occurrence of expression EXPR in OCCR_BB would reach |
a65f3558 | 5043 | block BB. |
7506f491 DE |
5044 | |
5045 | VISITED is a pointer to a working buffer for tracking which BB's have | |
5046 | been visited. It is NULL for the top-level call. | |
5047 | ||
5048 | We treat reaching expressions that go through blocks containing the same | |
5049 | reaching expression as "not reaching". E.g. if EXPR is generated in blocks | |
5050 | 2 and 3, INSN is in block 4, and 2->3->4, we treat the expression in block | |
5051 | 2 as not reaching. The intent is to improve the probability of finding | |
5052 | only one reaching expression and to reduce register lifetimes by picking | |
5053 | the closest such expression. */ | |
5054 | ||
5055 | static int | |
1d088dee | 5056 | pre_expr_reaches_here_p_work (basic_block occr_bb, struct expr *expr, basic_block bb, char *visited) |
7506f491 | 5057 | { |
36349f8b | 5058 | edge pred; |
7506f491 | 5059 | |
e2d2ed72 | 5060 | for (pred = bb->pred; pred != NULL; pred = pred->pred_next) |
7506f491 | 5061 | { |
e2d2ed72 | 5062 | basic_block pred_bb = pred->src; |
7506f491 | 5063 | |
36349f8b | 5064 | if (pred->src == ENTRY_BLOCK_PTR |
7506f491 | 5065 | /* Has predecessor has already been visited? */ |
0b17ab2f | 5066 | || visited[pred_bb->index]) |
c4c81601 RK |
5067 | ;/* Nothing to do. */ |
5068 | ||
7506f491 | 5069 | /* Does this predecessor generate this expression? */ |
0b17ab2f | 5070 | else if (TEST_BIT (comp[pred_bb->index], expr->bitmap_index)) |
7506f491 DE |
5071 | { |
5072 | /* Is this the occurrence we're looking for? | |
5073 | Note that there's only one generating occurrence per block | |
5074 | so we just need to check the block number. */ | |
a65f3558 | 5075 | if (occr_bb == pred_bb) |
7506f491 | 5076 | return 1; |
c4c81601 | 5077 | |
0b17ab2f | 5078 | visited[pred_bb->index] = 1; |
7506f491 DE |
5079 | } |
5080 | /* Ignore this predecessor if it kills the expression. */ | |
0b17ab2f RH |
5081 | else if (! TEST_BIT (transp[pred_bb->index], expr->bitmap_index)) |
5082 | visited[pred_bb->index] = 1; | |
c4c81601 | 5083 | |
7506f491 DE |
5084 | /* Neither gen nor kill. */ |
5085 | else | |
ac7c5af5 | 5086 | { |
0b17ab2f | 5087 | visited[pred_bb->index] = 1; |
89e606c9 | 5088 | if (pre_expr_reaches_here_p_work (occr_bb, expr, pred_bb, visited)) |
7506f491 | 5089 | return 1; |
ac7c5af5 | 5090 | } |
7506f491 DE |
5091 | } |
5092 | ||
5093 | /* All paths have been checked. */ | |
5094 | return 0; | |
5095 | } | |
283a2545 RL |
5096 | |
5097 | /* The wrapper for pre_expr_reaches_here_work that ensures that any | |
dc297297 | 5098 | memory allocated for that function is returned. */ |
283a2545 RL |
5099 | |
5100 | static int | |
1d088dee | 5101 | pre_expr_reaches_here_p (basic_block occr_bb, struct expr *expr, basic_block bb) |
283a2545 RL |
5102 | { |
5103 | int rval; | |
703ad42b | 5104 | char *visited = xcalloc (last_basic_block, 1); |
283a2545 | 5105 | |
8e42ace1 | 5106 | rval = pre_expr_reaches_here_p_work (occr_bb, expr, bb, visited); |
283a2545 RL |
5107 | |
5108 | free (visited); | |
c4c81601 | 5109 | return rval; |
283a2545 | 5110 | } |
7506f491 | 5111 | \f |
a42cd965 AM |
5112 | |
5113 | /* Given an expr, generate RTL which we can insert at the end of a BB, | |
589005ff | 5114 | or on an edge. Set the block number of any insns generated to |
a42cd965 AM |
5115 | the value of BB. */ |
5116 | ||
5117 | static rtx | |
1d088dee | 5118 | process_insert_insn (struct expr *expr) |
a42cd965 AM |
5119 | { |
5120 | rtx reg = expr->reaching_reg; | |
fb0c0a12 RK |
5121 | rtx exp = copy_rtx (expr->expr); |
5122 | rtx pat; | |
a42cd965 AM |
5123 | |
5124 | start_sequence (); | |
fb0c0a12 RK |
5125 | |
5126 | /* If the expression is something that's an operand, like a constant, | |
5127 | just copy it to a register. */ | |
5128 | if (general_operand (exp, GET_MODE (reg))) | |
5129 | emit_move_insn (reg, exp); | |
5130 | ||
5131 | /* Otherwise, make a new insn to compute this expression and make sure the | |
5132 | insn will be recognized (this also adds any needed CLOBBERs). Copy the | |
5133 | expression to make sure we don't have any sharing issues. */ | |
8d444206 | 5134 | else if (insn_invalid_p (emit_insn (gen_rtx_SET (VOIDmode, reg, exp)))) |
fb0c0a12 | 5135 | abort (); |
589005ff | 5136 | |
2f937369 | 5137 | pat = get_insns (); |
a42cd965 AM |
5138 | end_sequence (); |
5139 | ||
5140 | return pat; | |
5141 | } | |
589005ff | 5142 | |
a65f3558 JL |
5143 | /* Add EXPR to the end of basic block BB. |
5144 | ||
5145 | This is used by both the PRE and code hoisting. | |
5146 | ||
5147 | For PRE, we want to verify that the expr is either transparent | |
5148 | or locally anticipatable in the target block. This check makes | |
5149 | no sense for code hoisting. */ | |
7506f491 DE |
5150 | |
5151 | static void | |
1d088dee | 5152 | insert_insn_end_bb (struct expr *expr, basic_block bb, int pre) |
7506f491 | 5153 | { |
e2d2ed72 | 5154 | rtx insn = bb->end; |
7506f491 DE |
5155 | rtx new_insn; |
5156 | rtx reg = expr->reaching_reg; | |
5157 | int regno = REGNO (reg); | |
2f937369 | 5158 | rtx pat, pat_end; |
7506f491 | 5159 | |
a42cd965 | 5160 | pat = process_insert_insn (expr); |
2f937369 DM |
5161 | if (pat == NULL_RTX || ! INSN_P (pat)) |
5162 | abort (); | |
5163 | ||
5164 | pat_end = pat; | |
5165 | while (NEXT_INSN (pat_end) != NULL_RTX) | |
5166 | pat_end = NEXT_INSN (pat_end); | |
7506f491 DE |
5167 | |
5168 | /* If the last insn is a jump, insert EXPR in front [taking care to | |
4d6922ee | 5169 | handle cc0, etc. properly]. Similarly we need to care trapping |
068473ec | 5170 | instructions in presence of non-call exceptions. */ |
7506f491 | 5171 | |
068473ec JH |
5172 | if (GET_CODE (insn) == JUMP_INSN |
5173 | || (GET_CODE (insn) == INSN | |
5174 | && (bb->succ->succ_next || (bb->succ->flags & EDGE_ABNORMAL)))) | |
7506f491 | 5175 | { |
50b2596f | 5176 | #ifdef HAVE_cc0 |
7506f491 | 5177 | rtx note; |
50b2596f | 5178 | #endif |
068473ec JH |
5179 | /* It should always be the case that we can put these instructions |
5180 | anywhere in the basic block with performing PRE optimizations. | |
5181 | Check this. */ | |
3b25fbfe | 5182 | if (GET_CODE (insn) == INSN && pre |
0b17ab2f | 5183 | && !TEST_BIT (antloc[bb->index], expr->bitmap_index) |
589005ff | 5184 | && !TEST_BIT (transp[bb->index], expr->bitmap_index)) |
068473ec | 5185 | abort (); |
7506f491 DE |
5186 | |
5187 | /* If this is a jump table, then we can't insert stuff here. Since | |
5188 | we know the previous real insn must be the tablejump, we insert | |
5189 | the new instruction just before the tablejump. */ | |
5190 | if (GET_CODE (PATTERN (insn)) == ADDR_VEC | |
5191 | || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC) | |
5192 | insn = prev_real_insn (insn); | |
5193 | ||
5194 | #ifdef HAVE_cc0 | |
5195 | /* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts | |
5196 | if cc0 isn't set. */ | |
5197 | note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX); | |
5198 | if (note) | |
5199 | insn = XEXP (note, 0); | |
5200 | else | |
5201 | { | |
5202 | rtx maybe_cc0_setter = prev_nonnote_insn (insn); | |
5203 | if (maybe_cc0_setter | |
2c3c49de | 5204 | && INSN_P (maybe_cc0_setter) |
7506f491 DE |
5205 | && sets_cc0_p (PATTERN (maybe_cc0_setter))) |
5206 | insn = maybe_cc0_setter; | |
5207 | } | |
5208 | #endif | |
5209 | /* FIXME: What if something in cc0/jump uses value set in new insn? */ | |
3c030e88 | 5210 | new_insn = emit_insn_before (pat, insn); |
3947e2f9 | 5211 | } |
c4c81601 | 5212 | |
3947e2f9 RH |
5213 | /* Likewise if the last insn is a call, as will happen in the presence |
5214 | of exception handling. */ | |
068473ec JH |
5215 | else if (GET_CODE (insn) == CALL_INSN |
5216 | && (bb->succ->succ_next || (bb->succ->flags & EDGE_ABNORMAL))) | |
3947e2f9 | 5217 | { |
3947e2f9 RH |
5218 | /* Keeping in mind SMALL_REGISTER_CLASSES and parameters in registers, |
5219 | we search backward and place the instructions before the first | |
5220 | parameter is loaded. Do this for everyone for consistency and a | |
fbe5a4a6 | 5221 | presumption that we'll get better code elsewhere as well. |
3947e2f9 | 5222 | |
c4c81601 | 5223 | It should always be the case that we can put these instructions |
a65f3558 JL |
5224 | anywhere in the basic block with performing PRE optimizations. |
5225 | Check this. */ | |
c4c81601 | 5226 | |
a65f3558 | 5227 | if (pre |
0b17ab2f | 5228 | && !TEST_BIT (antloc[bb->index], expr->bitmap_index) |
589005ff | 5229 | && !TEST_BIT (transp[bb->index], expr->bitmap_index)) |
3947e2f9 RH |
5230 | abort (); |
5231 | ||
5232 | /* Since different machines initialize their parameter registers | |
5233 | in different orders, assume nothing. Collect the set of all | |
5234 | parameter registers. */ | |
833366d6 | 5235 | insn = find_first_parameter_load (insn, bb->head); |
3947e2f9 | 5236 | |
b1d26727 JL |
5237 | /* If we found all the parameter loads, then we want to insert |
5238 | before the first parameter load. | |
5239 | ||
5240 | If we did not find all the parameter loads, then we might have | |
5241 | stopped on the head of the block, which could be a CODE_LABEL. | |
5242 | If we inserted before the CODE_LABEL, then we would be putting | |
5243 | the insn in the wrong basic block. In that case, put the insn | |
b5229628 | 5244 | after the CODE_LABEL. Also, respect NOTE_INSN_BASIC_BLOCK. */ |
0a377997 | 5245 | while (GET_CODE (insn) == CODE_LABEL |
589ca5cb | 5246 | || NOTE_INSN_BASIC_BLOCK_P (insn)) |
b5229628 | 5247 | insn = NEXT_INSN (insn); |
c4c81601 | 5248 | |
3c030e88 | 5249 | new_insn = emit_insn_before (pat, insn); |
7506f491 DE |
5250 | } |
5251 | else | |
3c030e88 | 5252 | new_insn = emit_insn_after (pat, insn); |
7506f491 | 5253 | |
2f937369 | 5254 | while (1) |
a65f3558 | 5255 | { |
2f937369 | 5256 | if (INSN_P (pat)) |
a65f3558 | 5257 | { |
2f937369 DM |
5258 | add_label_notes (PATTERN (pat), new_insn); |
5259 | note_stores (PATTERN (pat), record_set_info, pat); | |
a65f3558 | 5260 | } |
2f937369 DM |
5261 | if (pat == pat_end) |
5262 | break; | |
5263 | pat = NEXT_INSN (pat); | |
a65f3558 | 5264 | } |
3947e2f9 | 5265 | |
7506f491 DE |
5266 | gcse_create_count++; |
5267 | ||
5268 | if (gcse_file) | |
5269 | { | |
c4c81601 | 5270 | fprintf (gcse_file, "PRE/HOIST: end of bb %d, insn %d, ", |
0b17ab2f | 5271 | bb->index, INSN_UID (new_insn)); |
c4c81601 RK |
5272 | fprintf (gcse_file, "copying expression %d to reg %d\n", |
5273 | expr->bitmap_index, regno); | |
7506f491 DE |
5274 | } |
5275 | } | |
5276 | ||
a42cd965 AM |
5277 | /* Insert partially redundant expressions on edges in the CFG to make |
5278 | the expressions fully redundant. */ | |
7506f491 | 5279 | |
a42cd965 | 5280 | static int |
1d088dee | 5281 | pre_edge_insert (struct edge_list *edge_list, struct expr **index_map) |
7506f491 | 5282 | { |
c4c81601 | 5283 | int e, i, j, num_edges, set_size, did_insert = 0; |
a65f3558 JL |
5284 | sbitmap *inserted; |
5285 | ||
a42cd965 AM |
5286 | /* Where PRE_INSERT_MAP is nonzero, we add the expression on that edge |
5287 | if it reaches any of the deleted expressions. */ | |
7506f491 | 5288 | |
a42cd965 AM |
5289 | set_size = pre_insert_map[0]->size; |
5290 | num_edges = NUM_EDGES (edge_list); | |
02280659 | 5291 | inserted = sbitmap_vector_alloc (num_edges, expr_hash_table.n_elems); |
a42cd965 | 5292 | sbitmap_vector_zero (inserted, num_edges); |
7506f491 | 5293 | |
a42cd965 | 5294 | for (e = 0; e < num_edges; e++) |
7506f491 DE |
5295 | { |
5296 | int indx; | |
e2d2ed72 | 5297 | basic_block bb = INDEX_EDGE_PRED_BB (edge_list, e); |
a65f3558 | 5298 | |
a65f3558 | 5299 | for (i = indx = 0; i < set_size; i++, indx += SBITMAP_ELT_BITS) |
7506f491 | 5300 | { |
a42cd965 | 5301 | SBITMAP_ELT_TYPE insert = pre_insert_map[e]->elms[i]; |
7506f491 | 5302 | |
02280659 | 5303 | for (j = indx; insert && j < (int) expr_hash_table.n_elems; j++, insert >>= 1) |
c4c81601 RK |
5304 | if ((insert & 1) != 0 && index_map[j]->reaching_reg != NULL_RTX) |
5305 | { | |
5306 | struct expr *expr = index_map[j]; | |
5307 | struct occr *occr; | |
a65f3558 | 5308 | |
ff7cc307 | 5309 | /* Now look at each deleted occurrence of this expression. */ |
c4c81601 RK |
5310 | for (occr = expr->antic_occr; occr != NULL; occr = occr->next) |
5311 | { | |
5312 | if (! occr->deleted_p) | |
5313 | continue; | |
5314 | ||
5315 | /* Insert this expression on this edge if if it would | |
ff7cc307 | 5316 | reach the deleted occurrence in BB. */ |
c4c81601 RK |
5317 | if (!TEST_BIT (inserted[e], j)) |
5318 | { | |
5319 | rtx insn; | |
5320 | edge eg = INDEX_EDGE (edge_list, e); | |
5321 | ||
5322 | /* We can't insert anything on an abnormal and | |
5323 | critical edge, so we insert the insn at the end of | |
5324 | the previous block. There are several alternatives | |
5325 | detailed in Morgans book P277 (sec 10.5) for | |
5326 | handling this situation. This one is easiest for | |
5327 | now. */ | |
5328 | ||
5329 | if ((eg->flags & EDGE_ABNORMAL) == EDGE_ABNORMAL) | |
5330 | insert_insn_end_bb (index_map[j], bb, 0); | |
5331 | else | |
5332 | { | |
5333 | insn = process_insert_insn (index_map[j]); | |
5334 | insert_insn_on_edge (insn, eg); | |
5335 | } | |
5336 | ||
5337 | if (gcse_file) | |
5338 | { | |
5339 | fprintf (gcse_file, "PRE/HOIST: edge (%d,%d), ", | |
0b17ab2f RH |
5340 | bb->index, |
5341 | INDEX_EDGE_SUCC_BB (edge_list, e)->index); | |
c4c81601 RK |
5342 | fprintf (gcse_file, "copy expression %d\n", |
5343 | expr->bitmap_index); | |
5344 | } | |
5345 | ||
a13d4ebf | 5346 | update_ld_motion_stores (expr); |
c4c81601 RK |
5347 | SET_BIT (inserted[e], j); |
5348 | did_insert = 1; | |
5349 | gcse_create_count++; | |
5350 | } | |
5351 | } | |
5352 | } | |
7506f491 DE |
5353 | } |
5354 | } | |
5faf03ae | 5355 | |
5a660bff | 5356 | sbitmap_vector_free (inserted); |
a42cd965 | 5357 | return did_insert; |
7506f491 DE |
5358 | } |
5359 | ||
c4c81601 | 5360 | /* Copy the result of INSN to REG. INDX is the expression number. */ |
7506f491 DE |
5361 | |
5362 | static void | |
1d088dee | 5363 | pre_insert_copy_insn (struct expr *expr, rtx insn) |
7506f491 DE |
5364 | { |
5365 | rtx reg = expr->reaching_reg; | |
5366 | int regno = REGNO (reg); | |
5367 | int indx = expr->bitmap_index; | |
5368 | rtx set = single_set (insn); | |
5369 | rtx new_insn; | |
5370 | ||
5371 | if (!set) | |
5372 | abort (); | |
c4c81601 | 5373 | |
47a3dae1 | 5374 | new_insn = emit_insn_after (gen_move_insn (reg, copy_rtx (SET_DEST (set))), insn); |
c4c81601 | 5375 | |
7506f491 DE |
5376 | /* Keep register set table up to date. */ |
5377 | record_one_set (regno, new_insn); | |
5378 | ||
5379 | gcse_create_count++; | |
5380 | ||
5381 | if (gcse_file) | |
a42cd965 AM |
5382 | fprintf (gcse_file, |
5383 | "PRE: bb %d, insn %d, copy expression %d in insn %d to reg %d\n", | |
5384 | BLOCK_NUM (insn), INSN_UID (new_insn), indx, | |
5385 | INSN_UID (insn), regno); | |
222f7ba9 | 5386 | update_ld_motion_stores (expr); |
7506f491 DE |
5387 | } |
5388 | ||
5389 | /* Copy available expressions that reach the redundant expression | |
5390 | to `reaching_reg'. */ | |
5391 | ||
5392 | static void | |
1d088dee | 5393 | pre_insert_copies (void) |
7506f491 | 5394 | { |
2e653e39 | 5395 | unsigned int i; |
c4c81601 RK |
5396 | struct expr *expr; |
5397 | struct occr *occr; | |
5398 | struct occr *avail; | |
a65f3558 | 5399 | |
7506f491 DE |
5400 | /* For each available expression in the table, copy the result to |
5401 | `reaching_reg' if the expression reaches a deleted one. | |
5402 | ||
5403 | ??? The current algorithm is rather brute force. | |
5404 | Need to do some profiling. */ | |
5405 | ||
02280659 ZD |
5406 | for (i = 0; i < expr_hash_table.size; i++) |
5407 | for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash) | |
c4c81601 RK |
5408 | { |
5409 | /* If the basic block isn't reachable, PPOUT will be TRUE. However, | |
5410 | we don't want to insert a copy here because the expression may not | |
5411 | really be redundant. So only insert an insn if the expression was | |
5412 | deleted. This test also avoids further processing if the | |
5413 | expression wasn't deleted anywhere. */ | |
5414 | if (expr->reaching_reg == NULL) | |
5415 | continue; | |
5416 | ||
5417 | for (occr = expr->antic_occr; occr != NULL; occr = occr->next) | |
5418 | { | |
5419 | if (! occr->deleted_p) | |
5420 | continue; | |
7506f491 | 5421 | |
c4c81601 RK |
5422 | for (avail = expr->avail_occr; avail != NULL; avail = avail->next) |
5423 | { | |
5424 | rtx insn = avail->insn; | |
7506f491 | 5425 | |
c4c81601 RK |
5426 | /* No need to handle this one if handled already. */ |
5427 | if (avail->copied_p) | |
5428 | continue; | |
7506f491 | 5429 | |
c4c81601 RK |
5430 | /* Don't handle this one if it's a redundant one. */ |
5431 | if (TEST_BIT (pre_redundant_insns, INSN_CUID (insn))) | |
5432 | continue; | |
7506f491 | 5433 | |
c4c81601 | 5434 | /* Or if the expression doesn't reach the deleted one. */ |
589005ff | 5435 | if (! pre_expr_reaches_here_p (BLOCK_FOR_INSN (avail->insn), |
e2d2ed72 AM |
5436 | expr, |
5437 | BLOCK_FOR_INSN (occr->insn))) | |
c4c81601 | 5438 | continue; |
7506f491 | 5439 | |
c4c81601 RK |
5440 | /* Copy the result of avail to reaching_reg. */ |
5441 | pre_insert_copy_insn (expr, insn); | |
5442 | avail->copied_p = 1; | |
5443 | } | |
5444 | } | |
5445 | } | |
7506f491 DE |
5446 | } |
5447 | ||
10d1bb36 JH |
5448 | /* Emit move from SRC to DEST noting the equivalence with expression computed |
5449 | in INSN. */ | |
5450 | static rtx | |
1d088dee | 5451 | gcse_emit_move_after (rtx src, rtx dest, rtx insn) |
10d1bb36 JH |
5452 | { |
5453 | rtx new; | |
6bdb8dd6 | 5454 | rtx set = single_set (insn), set2; |
10d1bb36 JH |
5455 | rtx note; |
5456 | rtx eqv; | |
5457 | ||
5458 | /* This should never fail since we're creating a reg->reg copy | |
5459 | we've verified to be valid. */ | |
5460 | ||
6bdb8dd6 | 5461 | new = emit_insn_after (gen_move_insn (dest, src), insn); |
285464d0 | 5462 | |
10d1bb36 | 5463 | /* Note the equivalence for local CSE pass. */ |
6bdb8dd6 JH |
5464 | set2 = single_set (new); |
5465 | if (!set2 || !rtx_equal_p (SET_DEST (set2), dest)) | |
5466 | return new; | |
10d1bb36 JH |
5467 | if ((note = find_reg_equal_equiv_note (insn))) |
5468 | eqv = XEXP (note, 0); | |
5469 | else | |
5470 | eqv = SET_SRC (set); | |
5471 | ||
a500466b | 5472 | set_unique_reg_note (new, REG_EQUAL, copy_insn_1 (eqv)); |
10d1bb36 JH |
5473 | |
5474 | return new; | |
5475 | } | |
5476 | ||
7506f491 | 5477 | /* Delete redundant computations. |
7506f491 DE |
5478 | Deletion is done by changing the insn to copy the `reaching_reg' of |
5479 | the expression into the result of the SET. It is left to later passes | |
5480 | (cprop, cse2, flow, combine, regmove) to propagate the copy or eliminate it. | |
5481 | ||
cc2902df | 5482 | Returns nonzero if a change is made. */ |
7506f491 DE |
5483 | |
5484 | static int | |
1d088dee | 5485 | pre_delete (void) |
7506f491 | 5486 | { |
2e653e39 | 5487 | unsigned int i; |
63bc1d05 | 5488 | int changed; |
c4c81601 RK |
5489 | struct expr *expr; |
5490 | struct occr *occr; | |
a65f3558 | 5491 | |
7506f491 | 5492 | changed = 0; |
02280659 ZD |
5493 | for (i = 0; i < expr_hash_table.size; i++) |
5494 | for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash) | |
c4c81601 RK |
5495 | { |
5496 | int indx = expr->bitmap_index; | |
7506f491 | 5497 | |
c4c81601 RK |
5498 | /* We only need to search antic_occr since we require |
5499 | ANTLOC != 0. */ | |
7506f491 | 5500 | |
c4c81601 RK |
5501 | for (occr = expr->antic_occr; occr != NULL; occr = occr->next) |
5502 | { | |
5503 | rtx insn = occr->insn; | |
5504 | rtx set; | |
e2d2ed72 | 5505 | basic_block bb = BLOCK_FOR_INSN (insn); |
7506f491 | 5506 | |
0b17ab2f | 5507 | if (TEST_BIT (pre_delete_map[bb->index], indx)) |
c4c81601 RK |
5508 | { |
5509 | set = single_set (insn); | |
5510 | if (! set) | |
5511 | abort (); | |
5512 | ||
5513 | /* Create a pseudo-reg to store the result of reaching | |
5514 | expressions into. Get the mode for the new pseudo from | |
5515 | the mode of the original destination pseudo. */ | |
5516 | if (expr->reaching_reg == NULL) | |
5517 | expr->reaching_reg | |
5518 | = gen_reg_rtx (GET_MODE (SET_DEST (set))); | |
5519 | ||
10d1bb36 JH |
5520 | gcse_emit_move_after (expr->reaching_reg, SET_DEST (set), insn); |
5521 | delete_insn (insn); | |
5522 | occr->deleted_p = 1; | |
5523 | SET_BIT (pre_redundant_insns, INSN_CUID (insn)); | |
5524 | changed = 1; | |
5525 | gcse_subst_count++; | |
7506f491 | 5526 | |
c4c81601 RK |
5527 | if (gcse_file) |
5528 | { | |
5529 | fprintf (gcse_file, | |
5530 | "PRE: redundant insn %d (expression %d) in ", | |
5531 | INSN_UID (insn), indx); | |
5532 | fprintf (gcse_file, "bb %d, reaching reg is %d\n", | |
0b17ab2f | 5533 | bb->index, REGNO (expr->reaching_reg)); |
c4c81601 RK |
5534 | } |
5535 | } | |
5536 | } | |
5537 | } | |
7506f491 DE |
5538 | |
5539 | return changed; | |
5540 | } | |
5541 | ||
5542 | /* Perform GCSE optimizations using PRE. | |
5543 | This is called by one_pre_gcse_pass after all the dataflow analysis | |
5544 | has been done. | |
5545 | ||
c4c81601 RK |
5546 | This is based on the original Morel-Renvoise paper Fred Chow's thesis, and |
5547 | lazy code motion from Knoop, Ruthing and Steffen as described in Advanced | |
5548 | Compiler Design and Implementation. | |
7506f491 | 5549 | |
c4c81601 RK |
5550 | ??? A new pseudo reg is created to hold the reaching expression. The nice |
5551 | thing about the classical approach is that it would try to use an existing | |
5552 | reg. If the register can't be adequately optimized [i.e. we introduce | |
5553 | reload problems], one could add a pass here to propagate the new register | |
5554 | through the block. | |
7506f491 | 5555 | |
c4c81601 RK |
5556 | ??? We don't handle single sets in PARALLELs because we're [currently] not |
5557 | able to copy the rest of the parallel when we insert copies to create full | |
5558 | redundancies from partial redundancies. However, there's no reason why we | |
5559 | can't handle PARALLELs in the cases where there are no partial | |
7506f491 DE |
5560 | redundancies. */ |
5561 | ||
5562 | static int | |
1d088dee | 5563 | pre_gcse (void) |
7506f491 | 5564 | { |
2e653e39 RK |
5565 | unsigned int i; |
5566 | int did_insert, changed; | |
7506f491 | 5567 | struct expr **index_map; |
c4c81601 | 5568 | struct expr *expr; |
7506f491 DE |
5569 | |
5570 | /* Compute a mapping from expression number (`bitmap_index') to | |
5571 | hash table entry. */ | |
5572 | ||
703ad42b | 5573 | index_map = xcalloc (expr_hash_table.n_elems, sizeof (struct expr *)); |
02280659 ZD |
5574 | for (i = 0; i < expr_hash_table.size; i++) |
5575 | for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash) | |
c4c81601 | 5576 | index_map[expr->bitmap_index] = expr; |
7506f491 DE |
5577 | |
5578 | /* Reset bitmap used to track which insns are redundant. */ | |
a65f3558 JL |
5579 | pre_redundant_insns = sbitmap_alloc (max_cuid); |
5580 | sbitmap_zero (pre_redundant_insns); | |
7506f491 DE |
5581 | |
5582 | /* Delete the redundant insns first so that | |
5583 | - we know what register to use for the new insns and for the other | |
5584 | ones with reaching expressions | |
5585 | - we know which insns are redundant when we go to create copies */ | |
c4c81601 | 5586 | |
7506f491 DE |
5587 | changed = pre_delete (); |
5588 | ||
a42cd965 | 5589 | did_insert = pre_edge_insert (edge_list, index_map); |
c4c81601 | 5590 | |
7506f491 | 5591 | /* In other places with reaching expressions, copy the expression to the |
a42cd965 | 5592 | specially allocated pseudo-reg that reaches the redundant expr. */ |
7506f491 | 5593 | pre_insert_copies (); |
a42cd965 AM |
5594 | if (did_insert) |
5595 | { | |
5596 | commit_edge_insertions (); | |
5597 | changed = 1; | |
5598 | } | |
7506f491 | 5599 | |
283a2545 | 5600 | free (index_map); |
76ac938b | 5601 | sbitmap_free (pre_redundant_insns); |
7506f491 DE |
5602 | return changed; |
5603 | } | |
5604 | ||
5605 | /* Top level routine to perform one PRE GCSE pass. | |
5606 | ||
cc2902df | 5607 | Return nonzero if a change was made. */ |
7506f491 DE |
5608 | |
5609 | static int | |
1d088dee | 5610 | one_pre_gcse_pass (int pass) |
7506f491 DE |
5611 | { |
5612 | int changed = 0; | |
5613 | ||
5614 | gcse_subst_count = 0; | |
5615 | gcse_create_count = 0; | |
5616 | ||
02280659 | 5617 | alloc_hash_table (max_cuid, &expr_hash_table, 0); |
a42cd965 | 5618 | add_noreturn_fake_exit_edges (); |
a13d4ebf AM |
5619 | if (flag_gcse_lm) |
5620 | compute_ld_motion_mems (); | |
5621 | ||
02280659 | 5622 | compute_hash_table (&expr_hash_table); |
a13d4ebf | 5623 | trim_ld_motion_mems (); |
7506f491 | 5624 | if (gcse_file) |
02280659 | 5625 | dump_hash_table (gcse_file, "Expression", &expr_hash_table); |
c4c81601 | 5626 | |
02280659 | 5627 | if (expr_hash_table.n_elems > 0) |
7506f491 | 5628 | { |
02280659 | 5629 | alloc_pre_mem (last_basic_block, expr_hash_table.n_elems); |
7506f491 DE |
5630 | compute_pre_data (); |
5631 | changed |= pre_gcse (); | |
a42cd965 | 5632 | free_edge_list (edge_list); |
7506f491 DE |
5633 | free_pre_mem (); |
5634 | } | |
c4c81601 | 5635 | |
a13d4ebf | 5636 | free_ldst_mems (); |
a42cd965 | 5637 | remove_fake_edges (); |
02280659 | 5638 | free_hash_table (&expr_hash_table); |
7506f491 DE |
5639 | |
5640 | if (gcse_file) | |
5641 | { | |
c4c81601 RK |
5642 | fprintf (gcse_file, "\nPRE GCSE of %s, pass %d: %d bytes needed, ", |
5643 | current_function_name, pass, bytes_used); | |
5644 | fprintf (gcse_file, "%d substs, %d insns created\n", | |
5645 | gcse_subst_count, gcse_create_count); | |
7506f491 DE |
5646 | } |
5647 | ||
5648 | return changed; | |
5649 | } | |
aeb2f500 JW |
5650 | \f |
5651 | /* If X contains any LABEL_REF's, add REG_LABEL notes for them to INSN. | |
5b1ef594 JDA |
5652 | If notes are added to an insn which references a CODE_LABEL, the |
5653 | LABEL_NUSES count is incremented. We have to add REG_LABEL notes, | |
5654 | because the following loop optimization pass requires them. */ | |
aeb2f500 JW |
5655 | |
5656 | /* ??? This is very similar to the loop.c add_label_notes function. We | |
5657 | could probably share code here. */ | |
5658 | ||
5659 | /* ??? If there was a jump optimization pass after gcse and before loop, | |
5660 | then we would not need to do this here, because jump would add the | |
5661 | necessary REG_LABEL notes. */ | |
5662 | ||
5663 | static void | |
1d088dee | 5664 | add_label_notes (rtx x, rtx insn) |
aeb2f500 JW |
5665 | { |
5666 | enum rtx_code code = GET_CODE (x); | |
5667 | int i, j; | |
6f7d635c | 5668 | const char *fmt; |
aeb2f500 JW |
5669 | |
5670 | if (code == LABEL_REF && !LABEL_REF_NONLOCAL_P (x)) | |
5671 | { | |
6b3603c2 | 5672 | /* This code used to ignore labels that referred to dispatch tables to |
e0bb17a8 | 5673 | avoid flow generating (slightly) worse code. |
6b3603c2 | 5674 | |
ac7c5af5 JL |
5675 | We no longer ignore such label references (see LABEL_REF handling in |
5676 | mark_jump_label for additional information). */ | |
c4c81601 | 5677 | |
6b8c9327 | 5678 | REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, XEXP (x, 0), |
6b3603c2 | 5679 | REG_NOTES (insn)); |
5b1ef594 | 5680 | if (LABEL_P (XEXP (x, 0))) |
589005ff | 5681 | LABEL_NUSES (XEXP (x, 0))++; |
aeb2f500 JW |
5682 | return; |
5683 | } | |
5684 | ||
c4c81601 | 5685 | for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--) |
aeb2f500 JW |
5686 | { |
5687 | if (fmt[i] == 'e') | |
5688 | add_label_notes (XEXP (x, i), insn); | |
5689 | else if (fmt[i] == 'E') | |
5690 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
5691 | add_label_notes (XVECEXP (x, i, j), insn); | |
5692 | } | |
5693 | } | |
a65f3558 JL |
5694 | |
5695 | /* Compute transparent outgoing information for each block. | |
5696 | ||
5697 | An expression is transparent to an edge unless it is killed by | |
5698 | the edge itself. This can only happen with abnormal control flow, | |
5699 | when the edge is traversed through a call. This happens with | |
5700 | non-local labels and exceptions. | |
5701 | ||
5702 | This would not be necessary if we split the edge. While this is | |
5703 | normally impossible for abnormal critical edges, with some effort | |
5704 | it should be possible with exception handling, since we still have | |
5705 | control over which handler should be invoked. But due to increased | |
5706 | EH table sizes, this may not be worthwhile. */ | |
5707 | ||
5708 | static void | |
1d088dee | 5709 | compute_transpout (void) |
a65f3558 | 5710 | { |
e0082a72 | 5711 | basic_block bb; |
2e653e39 | 5712 | unsigned int i; |
c4c81601 | 5713 | struct expr *expr; |
a65f3558 | 5714 | |
d55bc081 | 5715 | sbitmap_vector_ones (transpout, last_basic_block); |
a65f3558 | 5716 | |
e0082a72 | 5717 | FOR_EACH_BB (bb) |
a65f3558 | 5718 | { |
a65f3558 JL |
5719 | /* Note that flow inserted a nop a the end of basic blocks that |
5720 | end in call instructions for reasons other than abnormal | |
5721 | control flow. */ | |
e0082a72 | 5722 | if (GET_CODE (bb->end) != CALL_INSN) |
a65f3558 JL |
5723 | continue; |
5724 | ||
02280659 ZD |
5725 | for (i = 0; i < expr_hash_table.size; i++) |
5726 | for (expr = expr_hash_table.table[i]; expr ; expr = expr->next_same_hash) | |
c4c81601 RK |
5727 | if (GET_CODE (expr->expr) == MEM) |
5728 | { | |
5729 | if (GET_CODE (XEXP (expr->expr, 0)) == SYMBOL_REF | |
5730 | && CONSTANT_POOL_ADDRESS_P (XEXP (expr->expr, 0))) | |
5731 | continue; | |
589005ff | 5732 | |
c4c81601 RK |
5733 | /* ??? Optimally, we would use interprocedural alias |
5734 | analysis to determine if this mem is actually killed | |
5735 | by this call. */ | |
e0082a72 | 5736 | RESET_BIT (transpout[bb->index], expr->bitmap_index); |
c4c81601 | 5737 | } |
a65f3558 JL |
5738 | } |
5739 | } | |
dfdb644f JL |
5740 | |
5741 | /* Removal of useless null pointer checks */ | |
5742 | ||
dfdb644f | 5743 | /* Called via note_stores. X is set by SETTER. If X is a register we must |
0511851c MM |
5744 | invalidate nonnull_local and set nonnull_killed. DATA is really a |
5745 | `null_pointer_info *'. | |
dfdb644f JL |
5746 | |
5747 | We ignore hard registers. */ | |
c4c81601 | 5748 | |
dfdb644f | 5749 | static void |
1d088dee | 5750 | invalidate_nonnull_info (rtx x, rtx setter ATTRIBUTE_UNUSED, void *data) |
dfdb644f | 5751 | { |
770ae6cc RK |
5752 | unsigned int regno; |
5753 | struct null_pointer_info *npi = (struct null_pointer_info *) data; | |
c4c81601 | 5754 | |
dfdb644f JL |
5755 | while (GET_CODE (x) == SUBREG) |
5756 | x = SUBREG_REG (x); | |
5757 | ||
5758 | /* Ignore anything that is not a register or is a hard register. */ | |
5759 | if (GET_CODE (x) != REG | |
0511851c MM |
5760 | || REGNO (x) < npi->min_reg |
5761 | || REGNO (x) >= npi->max_reg) | |
dfdb644f JL |
5762 | return; |
5763 | ||
0511851c | 5764 | regno = REGNO (x) - npi->min_reg; |
dfdb644f | 5765 | |
e0082a72 ZD |
5766 | RESET_BIT (npi->nonnull_local[npi->current_block->index], regno); |
5767 | SET_BIT (npi->nonnull_killed[npi->current_block->index], regno); | |
dfdb644f JL |
5768 | } |
5769 | ||
0511851c MM |
5770 | /* Do null-pointer check elimination for the registers indicated in |
5771 | NPI. NONNULL_AVIN and NONNULL_AVOUT are pre-allocated sbitmaps; | |
5772 | they are not our responsibility to free. */ | |
dfdb644f | 5773 | |
99a15921 | 5774 | static int |
1d088dee AJ |
5775 | delete_null_pointer_checks_1 (unsigned int *block_reg, sbitmap *nonnull_avin, |
5776 | sbitmap *nonnull_avout, | |
5777 | struct null_pointer_info *npi) | |
dfdb644f | 5778 | { |
e0082a72 | 5779 | basic_block bb, current_block; |
0511851c MM |
5780 | sbitmap *nonnull_local = npi->nonnull_local; |
5781 | sbitmap *nonnull_killed = npi->nonnull_killed; | |
99a15921 | 5782 | int something_changed = 0; |
589005ff | 5783 | |
dfdb644f JL |
5784 | /* Compute local properties, nonnull and killed. A register will have |
5785 | the nonnull property if at the end of the current block its value is | |
5786 | known to be nonnull. The killed property indicates that somewhere in | |
5787 | the block any information we had about the register is killed. | |
5788 | ||
5789 | Note that a register can have both properties in a single block. That | |
5790 | indicates that it's killed, then later in the block a new value is | |
5791 | computed. */ | |
d55bc081 ZD |
5792 | sbitmap_vector_zero (nonnull_local, last_basic_block); |
5793 | sbitmap_vector_zero (nonnull_killed, last_basic_block); | |
c4c81601 | 5794 | |
e0082a72 | 5795 | FOR_EACH_BB (current_block) |
dfdb644f JL |
5796 | { |
5797 | rtx insn, stop_insn; | |
5798 | ||
0511851c MM |
5799 | /* Set the current block for invalidate_nonnull_info. */ |
5800 | npi->current_block = current_block; | |
5801 | ||
dfdb644f JL |
5802 | /* Scan each insn in the basic block looking for memory references and |
5803 | register sets. */ | |
e0082a72 ZD |
5804 | stop_insn = NEXT_INSN (current_block->end); |
5805 | for (insn = current_block->head; | |
dfdb644f JL |
5806 | insn != stop_insn; |
5807 | insn = NEXT_INSN (insn)) | |
5808 | { | |
5809 | rtx set; | |
0511851c | 5810 | rtx reg; |
dfdb644f JL |
5811 | |
5812 | /* Ignore anything that is not a normal insn. */ | |
2c3c49de | 5813 | if (! INSN_P (insn)) |
dfdb644f JL |
5814 | continue; |
5815 | ||
5816 | /* Basically ignore anything that is not a simple SET. We do have | |
5817 | to make sure to invalidate nonnull_local and set nonnull_killed | |
5818 | for such insns though. */ | |
5819 | set = single_set (insn); | |
5820 | if (!set) | |
5821 | { | |
0511851c | 5822 | note_stores (PATTERN (insn), invalidate_nonnull_info, npi); |
dfdb644f JL |
5823 | continue; |
5824 | } | |
5825 | ||
f63d1bf7 | 5826 | /* See if we've got a usable memory load. We handle it first |
dfdb644f JL |
5827 | in case it uses its address register as a dest (which kills |
5828 | the nonnull property). */ | |
5829 | if (GET_CODE (SET_SRC (set)) == MEM | |
0511851c MM |
5830 | && GET_CODE ((reg = XEXP (SET_SRC (set), 0))) == REG |
5831 | && REGNO (reg) >= npi->min_reg | |
5832 | && REGNO (reg) < npi->max_reg) | |
e0082a72 | 5833 | SET_BIT (nonnull_local[current_block->index], |
0511851c | 5834 | REGNO (reg) - npi->min_reg); |
dfdb644f JL |
5835 | |
5836 | /* Now invalidate stuff clobbered by this insn. */ | |
0511851c | 5837 | note_stores (PATTERN (insn), invalidate_nonnull_info, npi); |
dfdb644f JL |
5838 | |
5839 | /* And handle stores, we do these last since any sets in INSN can | |
5840 | not kill the nonnull property if it is derived from a MEM | |
5841 | appearing in a SET_DEST. */ | |
5842 | if (GET_CODE (SET_DEST (set)) == MEM | |
0511851c MM |
5843 | && GET_CODE ((reg = XEXP (SET_DEST (set), 0))) == REG |
5844 | && REGNO (reg) >= npi->min_reg | |
5845 | && REGNO (reg) < npi->max_reg) | |
e0082a72 | 5846 | SET_BIT (nonnull_local[current_block->index], |
0511851c | 5847 | REGNO (reg) - npi->min_reg); |
dfdb644f JL |
5848 | } |
5849 | } | |
5850 | ||
5851 | /* Now compute global properties based on the local properties. This | |
fbe5a4a6 | 5852 | is a classic global availability algorithm. */ |
ce724250 JL |
5853 | compute_available (nonnull_local, nonnull_killed, |
5854 | nonnull_avout, nonnull_avin); | |
dfdb644f JL |
5855 | |
5856 | /* Now look at each bb and see if it ends with a compare of a value | |
5857 | against zero. */ | |
e0082a72 | 5858 | FOR_EACH_BB (bb) |
dfdb644f | 5859 | { |
e0082a72 | 5860 | rtx last_insn = bb->end; |
0511851c | 5861 | rtx condition, earliest; |
dfdb644f JL |
5862 | int compare_and_branch; |
5863 | ||
0511851c MM |
5864 | /* Since MIN_REG is always at least FIRST_PSEUDO_REGISTER, and |
5865 | since BLOCK_REG[BB] is zero if this block did not end with a | |
5866 | comparison against zero, this condition works. */ | |
e0082a72 ZD |
5867 | if (block_reg[bb->index] < npi->min_reg |
5868 | || block_reg[bb->index] >= npi->max_reg) | |
dfdb644f JL |
5869 | continue; |
5870 | ||
5871 | /* LAST_INSN is a conditional jump. Get its condition. */ | |
5872 | condition = get_condition (last_insn, &earliest); | |
5873 | ||
40d7a3fe NB |
5874 | /* If we can't determine the condition then skip. */ |
5875 | if (! condition) | |
5876 | continue; | |
5877 | ||
dfdb644f | 5878 | /* Is the register known to have a nonzero value? */ |
e0082a72 | 5879 | if (!TEST_BIT (nonnull_avout[bb->index], block_reg[bb->index] - npi->min_reg)) |
dfdb644f JL |
5880 | continue; |
5881 | ||
5882 | /* Try to compute whether the compare/branch at the loop end is one or | |
5883 | two instructions. */ | |
5884 | if (earliest == last_insn) | |
5885 | compare_and_branch = 1; | |
5886 | else if (earliest == prev_nonnote_insn (last_insn)) | |
5887 | compare_and_branch = 2; | |
5888 | else | |
5889 | continue; | |
5890 | ||
5891 | /* We know the register in this comparison is nonnull at exit from | |
5892 | this block. We can optimize this comparison. */ | |
5893 | if (GET_CODE (condition) == NE) | |
5894 | { | |
5895 | rtx new_jump; | |
5896 | ||
38c1593d JH |
5897 | new_jump = emit_jump_insn_after (gen_jump (JUMP_LABEL (last_insn)), |
5898 | last_insn); | |
dfdb644f JL |
5899 | JUMP_LABEL (new_jump) = JUMP_LABEL (last_insn); |
5900 | LABEL_NUSES (JUMP_LABEL (new_jump))++; | |
5901 | emit_barrier_after (new_jump); | |
5902 | } | |
8e184d9c | 5903 | |
99a15921 | 5904 | something_changed = 1; |
9cd56be1 | 5905 | delete_insn (last_insn); |
dfdb644f | 5906 | if (compare_and_branch == 2) |
589005ff | 5907 | delete_insn (earliest); |
e0082a72 | 5908 | purge_dead_edges (bb); |
0511851c MM |
5909 | |
5910 | /* Don't check this block again. (Note that BLOCK_END is | |
589005ff | 5911 | invalid here; we deleted the last instruction in the |
0511851c | 5912 | block.) */ |
e0082a72 | 5913 | block_reg[bb->index] = 0; |
0511851c | 5914 | } |
99a15921 JL |
5915 | |
5916 | return something_changed; | |
0511851c MM |
5917 | } |
5918 | ||
5919 | /* Find EQ/NE comparisons against zero which can be (indirectly) evaluated | |
5920 | at compile time. | |
5921 | ||
5922 | This is conceptually similar to global constant/copy propagation and | |
5923 | classic global CSE (it even uses the same dataflow equations as cprop). | |
5924 | ||
5925 | If a register is used as memory address with the form (mem (reg)), then we | |
5926 | know that REG can not be zero at that point in the program. Any instruction | |
5927 | which sets REG "kills" this property. | |
5928 | ||
5929 | So, if every path leading to a conditional branch has an available memory | |
5930 | reference of that form, then we know the register can not have the value | |
589005ff | 5931 | zero at the conditional branch. |
0511851c | 5932 | |
fbe5a4a6 | 5933 | So we merely need to compute the local properties and propagate that data |
0511851c MM |
5934 | around the cfg, then optimize where possible. |
5935 | ||
5936 | We run this pass two times. Once before CSE, then again after CSE. This | |
5937 | has proven to be the most profitable approach. It is rare for new | |
5938 | optimization opportunities of this nature to appear after the first CSE | |
5939 | pass. | |
5940 | ||
5941 | This could probably be integrated with global cprop with a little work. */ | |
5942 | ||
99a15921 | 5943 | int |
1d088dee | 5944 | delete_null_pointer_checks (rtx f ATTRIBUTE_UNUSED) |
0511851c | 5945 | { |
0511851c | 5946 | sbitmap *nonnull_avin, *nonnull_avout; |
770ae6cc | 5947 | unsigned int *block_reg; |
e0082a72 | 5948 | basic_block bb; |
0511851c MM |
5949 | int reg; |
5950 | int regs_per_pass; | |
5951 | int max_reg; | |
5952 | struct null_pointer_info npi; | |
99a15921 | 5953 | int something_changed = 0; |
0511851c | 5954 | |
0511851c | 5955 | /* If we have only a single block, then there's nothing to do. */ |
0b17ab2f | 5956 | if (n_basic_blocks <= 1) |
99a15921 | 5957 | return 0; |
0511851c MM |
5958 | |
5959 | /* Trying to perform global optimizations on flow graphs which have | |
5960 | a high connectivity will take a long time and is unlikely to be | |
5961 | particularly useful. | |
5962 | ||
43e72072 | 5963 | In normal circumstances a cfg should have about twice as many edges |
0511851c MM |
5964 | as blocks. But we do not want to punish small functions which have |
5965 | a couple switch statements. So we require a relatively large number | |
5966 | of basic blocks and the ratio of edges to blocks to be high. */ | |
0b17ab2f | 5967 | if (n_basic_blocks > 1000 && n_edges / n_basic_blocks >= 20) |
99a15921 | 5968 | return 0; |
0511851c | 5969 | |
0511851c MM |
5970 | /* We need four bitmaps, each with a bit for each register in each |
5971 | basic block. */ | |
5972 | max_reg = max_reg_num (); | |
d55bc081 | 5973 | regs_per_pass = get_bitmap_width (4, last_basic_block, max_reg); |
0511851c MM |
5974 | |
5975 | /* Allocate bitmaps to hold local and global properties. */ | |
d55bc081 ZD |
5976 | npi.nonnull_local = sbitmap_vector_alloc (last_basic_block, regs_per_pass); |
5977 | npi.nonnull_killed = sbitmap_vector_alloc (last_basic_block, regs_per_pass); | |
5978 | nonnull_avin = sbitmap_vector_alloc (last_basic_block, regs_per_pass); | |
5979 | nonnull_avout = sbitmap_vector_alloc (last_basic_block, regs_per_pass); | |
0511851c MM |
5980 | |
5981 | /* Go through the basic blocks, seeing whether or not each block | |
5982 | ends with a conditional branch whose condition is a comparison | |
5983 | against zero. Record the register compared in BLOCK_REG. */ | |
703ad42b | 5984 | block_reg = xcalloc (last_basic_block, sizeof (int)); |
e0082a72 | 5985 | FOR_EACH_BB (bb) |
0511851c | 5986 | { |
e0082a72 | 5987 | rtx last_insn = bb->end; |
0511851c MM |
5988 | rtx condition, earliest, reg; |
5989 | ||
5990 | /* We only want conditional branches. */ | |
5991 | if (GET_CODE (last_insn) != JUMP_INSN | |
7f1c097d JH |
5992 | || !any_condjump_p (last_insn) |
5993 | || !onlyjump_p (last_insn)) | |
0511851c MM |
5994 | continue; |
5995 | ||
5996 | /* LAST_INSN is a conditional jump. Get its condition. */ | |
5997 | condition = get_condition (last_insn, &earliest); | |
5998 | ||
4fe9b91c | 5999 | /* If we were unable to get the condition, or it is not an equality |
0511851c MM |
6000 | comparison against zero then there's nothing we can do. */ |
6001 | if (!condition | |
6002 | || (GET_CODE (condition) != NE && GET_CODE (condition) != EQ) | |
6003 | || GET_CODE (XEXP (condition, 1)) != CONST_INT | |
589005ff | 6004 | || (XEXP (condition, 1) |
0511851c MM |
6005 | != CONST0_RTX (GET_MODE (XEXP (condition, 0))))) |
6006 | continue; | |
6007 | ||
6008 | /* We must be checking a register against zero. */ | |
6009 | reg = XEXP (condition, 0); | |
6010 | if (GET_CODE (reg) != REG) | |
6011 | continue; | |
6012 | ||
e0082a72 | 6013 | block_reg[bb->index] = REGNO (reg); |
0511851c MM |
6014 | } |
6015 | ||
6016 | /* Go through the algorithm for each block of registers. */ | |
6017 | for (reg = FIRST_PSEUDO_REGISTER; reg < max_reg; reg += regs_per_pass) | |
6018 | { | |
6019 | npi.min_reg = reg; | |
6020 | npi.max_reg = MIN (reg + regs_per_pass, max_reg); | |
99a15921 JL |
6021 | something_changed |= delete_null_pointer_checks_1 (block_reg, |
6022 | nonnull_avin, | |
6023 | nonnull_avout, | |
6024 | &npi); | |
dfdb644f JL |
6025 | } |
6026 | ||
0511851c MM |
6027 | /* Free the table of registers compared at the end of every block. */ |
6028 | free (block_reg); | |
6029 | ||
dfdb644f | 6030 | /* Free bitmaps. */ |
5a660bff DB |
6031 | sbitmap_vector_free (npi.nonnull_local); |
6032 | sbitmap_vector_free (npi.nonnull_killed); | |
6033 | sbitmap_vector_free (nonnull_avin); | |
6034 | sbitmap_vector_free (nonnull_avout); | |
99a15921 JL |
6035 | |
6036 | return something_changed; | |
dfdb644f | 6037 | } |
bb457bd9 JL |
6038 | |
6039 | /* Code Hoisting variables and subroutines. */ | |
6040 | ||
6041 | /* Very busy expressions. */ | |
6042 | static sbitmap *hoist_vbein; | |
6043 | static sbitmap *hoist_vbeout; | |
6044 | ||
6045 | /* Hoistable expressions. */ | |
6046 | static sbitmap *hoist_exprs; | |
6047 | ||
6048 | /* Dominator bitmaps. */ | |
355be0dc | 6049 | dominance_info dominators; |
bb457bd9 JL |
6050 | |
6051 | /* ??? We could compute post dominators and run this algorithm in | |
68e82b83 | 6052 | reverse to perform tail merging, doing so would probably be |
bb457bd9 JL |
6053 | more effective than the tail merging code in jump.c. |
6054 | ||
6055 | It's unclear if tail merging could be run in parallel with | |
6056 | code hoisting. It would be nice. */ | |
6057 | ||
6058 | /* Allocate vars used for code hoisting analysis. */ | |
6059 | ||
6060 | static void | |
1d088dee | 6061 | alloc_code_hoist_mem (int n_blocks, int n_exprs) |
bb457bd9 JL |
6062 | { |
6063 | antloc = sbitmap_vector_alloc (n_blocks, n_exprs); | |
6064 | transp = sbitmap_vector_alloc (n_blocks, n_exprs); | |
6065 | comp = sbitmap_vector_alloc (n_blocks, n_exprs); | |
6066 | ||
6067 | hoist_vbein = sbitmap_vector_alloc (n_blocks, n_exprs); | |
6068 | hoist_vbeout = sbitmap_vector_alloc (n_blocks, n_exprs); | |
6069 | hoist_exprs = sbitmap_vector_alloc (n_blocks, n_exprs); | |
6070 | transpout = sbitmap_vector_alloc (n_blocks, n_exprs); | |
bb457bd9 JL |
6071 | } |
6072 | ||
6073 | /* Free vars used for code hoisting analysis. */ | |
6074 | ||
6075 | static void | |
1d088dee | 6076 | free_code_hoist_mem (void) |
bb457bd9 | 6077 | { |
5a660bff DB |
6078 | sbitmap_vector_free (antloc); |
6079 | sbitmap_vector_free (transp); | |
6080 | sbitmap_vector_free (comp); | |
bb457bd9 | 6081 | |
5a660bff DB |
6082 | sbitmap_vector_free (hoist_vbein); |
6083 | sbitmap_vector_free (hoist_vbeout); | |
6084 | sbitmap_vector_free (hoist_exprs); | |
6085 | sbitmap_vector_free (transpout); | |
bb457bd9 | 6086 | |
355be0dc | 6087 | free_dominance_info (dominators); |
bb457bd9 JL |
6088 | } |
6089 | ||
6090 | /* Compute the very busy expressions at entry/exit from each block. | |
6091 | ||
6092 | An expression is very busy if all paths from a given point | |
6093 | compute the expression. */ | |
6094 | ||
6095 | static void | |
1d088dee | 6096 | compute_code_hoist_vbeinout (void) |
bb457bd9 | 6097 | { |
e0082a72 ZD |
6098 | int changed, passes; |
6099 | basic_block bb; | |
bb457bd9 | 6100 | |
d55bc081 ZD |
6101 | sbitmap_vector_zero (hoist_vbeout, last_basic_block); |
6102 | sbitmap_vector_zero (hoist_vbein, last_basic_block); | |
bb457bd9 JL |
6103 | |
6104 | passes = 0; | |
6105 | changed = 1; | |
c4c81601 | 6106 | |
bb457bd9 JL |
6107 | while (changed) |
6108 | { | |
6109 | changed = 0; | |
c4c81601 | 6110 | |
bb457bd9 JL |
6111 | /* We scan the blocks in the reverse order to speed up |
6112 | the convergence. */ | |
e0082a72 | 6113 | FOR_EACH_BB_REVERSE (bb) |
bb457bd9 | 6114 | { |
e0082a72 ZD |
6115 | changed |= sbitmap_a_or_b_and_c_cg (hoist_vbein[bb->index], antloc[bb->index], |
6116 | hoist_vbeout[bb->index], transp[bb->index]); | |
6117 | if (bb->next_bb != EXIT_BLOCK_PTR) | |
6118 | sbitmap_intersection_of_succs (hoist_vbeout[bb->index], hoist_vbein, bb->index); | |
bb457bd9 | 6119 | } |
c4c81601 | 6120 | |
bb457bd9 JL |
6121 | passes++; |
6122 | } | |
6123 | ||
6124 | if (gcse_file) | |
6125 | fprintf (gcse_file, "hoisting vbeinout computation: %d passes\n", passes); | |
6126 | } | |
6127 | ||
6128 | /* Top level routine to do the dataflow analysis needed by code hoisting. */ | |
6129 | ||
6130 | static void | |
1d088dee | 6131 | compute_code_hoist_data (void) |
bb457bd9 | 6132 | { |
02280659 | 6133 | compute_local_properties (transp, comp, antloc, &expr_hash_table); |
bb457bd9 JL |
6134 | compute_transpout (); |
6135 | compute_code_hoist_vbeinout (); | |
355be0dc | 6136 | dominators = calculate_dominance_info (CDI_DOMINATORS); |
bb457bd9 JL |
6137 | if (gcse_file) |
6138 | fprintf (gcse_file, "\n"); | |
6139 | } | |
6140 | ||
6141 | /* Determine if the expression identified by EXPR_INDEX would | |
6142 | reach BB unimpared if it was placed at the end of EXPR_BB. | |
6143 | ||
6144 | It's unclear exactly what Muchnick meant by "unimpared". It seems | |
6145 | to me that the expression must either be computed or transparent in | |
6146 | *every* block in the path(s) from EXPR_BB to BB. Any other definition | |
6147 | would allow the expression to be hoisted out of loops, even if | |
6148 | the expression wasn't a loop invariant. | |
6149 | ||
6150 | Contrast this to reachability for PRE where an expression is | |
6151 | considered reachable if *any* path reaches instead of *all* | |
6152 | paths. */ | |
6153 | ||
6154 | static int | |
1d088dee | 6155 | hoist_expr_reaches_here_p (basic_block expr_bb, int expr_index, basic_block bb, char *visited) |
bb457bd9 JL |
6156 | { |
6157 | edge pred; | |
283a2545 | 6158 | int visited_allocated_locally = 0; |
589005ff | 6159 | |
bb457bd9 JL |
6160 | |
6161 | if (visited == NULL) | |
6162 | { | |
8e42ace1 | 6163 | visited_allocated_locally = 1; |
d55bc081 | 6164 | visited = xcalloc (last_basic_block, 1); |
bb457bd9 JL |
6165 | } |
6166 | ||
e2d2ed72 | 6167 | for (pred = bb->pred; pred != NULL; pred = pred->pred_next) |
bb457bd9 | 6168 | { |
e2d2ed72 | 6169 | basic_block pred_bb = pred->src; |
bb457bd9 JL |
6170 | |
6171 | if (pred->src == ENTRY_BLOCK_PTR) | |
6172 | break; | |
f305679f JH |
6173 | else if (pred_bb == expr_bb) |
6174 | continue; | |
0b17ab2f | 6175 | else if (visited[pred_bb->index]) |
bb457bd9 | 6176 | continue; |
c4c81601 | 6177 | |
bb457bd9 | 6178 | /* Does this predecessor generate this expression? */ |
0b17ab2f | 6179 | else if (TEST_BIT (comp[pred_bb->index], expr_index)) |
bb457bd9 | 6180 | break; |
0b17ab2f | 6181 | else if (! TEST_BIT (transp[pred_bb->index], expr_index)) |
bb457bd9 | 6182 | break; |
c4c81601 | 6183 | |
bb457bd9 JL |
6184 | /* Not killed. */ |
6185 | else | |
6186 | { | |
0b17ab2f | 6187 | visited[pred_bb->index] = 1; |
bb457bd9 JL |
6188 | if (! hoist_expr_reaches_here_p (expr_bb, expr_index, |
6189 | pred_bb, visited)) | |
6190 | break; | |
6191 | } | |
6192 | } | |
589005ff | 6193 | if (visited_allocated_locally) |
283a2545 | 6194 | free (visited); |
c4c81601 | 6195 | |
bb457bd9 JL |
6196 | return (pred == NULL); |
6197 | } | |
6198 | \f | |
6199 | /* Actually perform code hoisting. */ | |
c4c81601 | 6200 | |
bb457bd9 | 6201 | static void |
1d088dee | 6202 | hoist_code (void) |
bb457bd9 | 6203 | { |
e0082a72 | 6204 | basic_block bb, dominated; |
c635a1ec DB |
6205 | basic_block *domby; |
6206 | unsigned int domby_len; | |
6207 | unsigned int i,j; | |
bb457bd9 | 6208 | struct expr **index_map; |
c4c81601 | 6209 | struct expr *expr; |
bb457bd9 | 6210 | |
d55bc081 | 6211 | sbitmap_vector_zero (hoist_exprs, last_basic_block); |
bb457bd9 JL |
6212 | |
6213 | /* Compute a mapping from expression number (`bitmap_index') to | |
6214 | hash table entry. */ | |
6215 | ||
703ad42b | 6216 | index_map = xcalloc (expr_hash_table.n_elems, sizeof (struct expr *)); |
02280659 ZD |
6217 | for (i = 0; i < expr_hash_table.size; i++) |
6218 | for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash) | |
c4c81601 | 6219 | index_map[expr->bitmap_index] = expr; |
bb457bd9 JL |
6220 | |
6221 | /* Walk over each basic block looking for potentially hoistable | |
6222 | expressions, nothing gets hoisted from the entry block. */ | |
e0082a72 | 6223 | FOR_EACH_BB (bb) |
bb457bd9 JL |
6224 | { |
6225 | int found = 0; | |
6226 | int insn_inserted_p; | |
6227 | ||
c635a1ec | 6228 | domby_len = get_dominated_by (dominators, bb, &domby); |
bb457bd9 JL |
6229 | /* Examine each expression that is very busy at the exit of this |
6230 | block. These are the potentially hoistable expressions. */ | |
e0082a72 | 6231 | for (i = 0; i < hoist_vbeout[bb->index]->n_bits; i++) |
bb457bd9 JL |
6232 | { |
6233 | int hoistable = 0; | |
c4c81601 | 6234 | |
c635a1ec DB |
6235 | if (TEST_BIT (hoist_vbeout[bb->index], i) |
6236 | && TEST_BIT (transpout[bb->index], i)) | |
bb457bd9 JL |
6237 | { |
6238 | /* We've found a potentially hoistable expression, now | |
6239 | we look at every block BB dominates to see if it | |
6240 | computes the expression. */ | |
c635a1ec | 6241 | for (j = 0; j < domby_len; j++) |
bb457bd9 | 6242 | { |
c635a1ec | 6243 | dominated = domby[j]; |
bb457bd9 | 6244 | /* Ignore self dominance. */ |
c635a1ec | 6245 | if (bb == dominated) |
bb457bd9 | 6246 | continue; |
bb457bd9 JL |
6247 | /* We've found a dominated block, now see if it computes |
6248 | the busy expression and whether or not moving that | |
6249 | expression to the "beginning" of that block is safe. */ | |
e0082a72 | 6250 | if (!TEST_BIT (antloc[dominated->index], i)) |
bb457bd9 JL |
6251 | continue; |
6252 | ||
6253 | /* Note if the expression would reach the dominated block | |
589005ff | 6254 | unimpared if it was placed at the end of BB. |
bb457bd9 JL |
6255 | |
6256 | Keep track of how many times this expression is hoistable | |
6257 | from a dominated block into BB. */ | |
e0082a72 | 6258 | if (hoist_expr_reaches_here_p (bb, i, dominated, NULL)) |
bb457bd9 JL |
6259 | hoistable++; |
6260 | } | |
6261 | ||
ff7cc307 | 6262 | /* If we found more than one hoistable occurrence of this |
bb457bd9 JL |
6263 | expression, then note it in the bitmap of expressions to |
6264 | hoist. It makes no sense to hoist things which are computed | |
6265 | in only one BB, and doing so tends to pessimize register | |
6266 | allocation. One could increase this value to try harder | |
6267 | to avoid any possible code expansion due to register | |
6268 | allocation issues; however experiments have shown that | |
6269 | the vast majority of hoistable expressions are only movable | |
e0bb17a8 | 6270 | from two successors, so raising this threshold is likely |
bb457bd9 JL |
6271 | to nullify any benefit we get from code hoisting. */ |
6272 | if (hoistable > 1) | |
6273 | { | |
e0082a72 | 6274 | SET_BIT (hoist_exprs[bb->index], i); |
bb457bd9 JL |
6275 | found = 1; |
6276 | } | |
6277 | } | |
6278 | } | |
bb457bd9 JL |
6279 | /* If we found nothing to hoist, then quit now. */ |
6280 | if (! found) | |
c635a1ec | 6281 | { |
1d088dee | 6282 | free (domby); |
bb457bd9 | 6283 | continue; |
c635a1ec | 6284 | } |
bb457bd9 JL |
6285 | |
6286 | /* Loop over all the hoistable expressions. */ | |
e0082a72 | 6287 | for (i = 0; i < hoist_exprs[bb->index]->n_bits; i++) |
bb457bd9 JL |
6288 | { |
6289 | /* We want to insert the expression into BB only once, so | |
6290 | note when we've inserted it. */ | |
6291 | insn_inserted_p = 0; | |
6292 | ||
6293 | /* These tests should be the same as the tests above. */ | |
e0082a72 | 6294 | if (TEST_BIT (hoist_vbeout[bb->index], i)) |
bb457bd9 JL |
6295 | { |
6296 | /* We've found a potentially hoistable expression, now | |
6297 | we look at every block BB dominates to see if it | |
6298 | computes the expression. */ | |
c635a1ec | 6299 | for (j = 0; j < domby_len; j++) |
bb457bd9 | 6300 | { |
c635a1ec | 6301 | dominated = domby[j]; |
bb457bd9 | 6302 | /* Ignore self dominance. */ |
c635a1ec | 6303 | if (bb == dominated) |
bb457bd9 JL |
6304 | continue; |
6305 | ||
6306 | /* We've found a dominated block, now see if it computes | |
6307 | the busy expression and whether or not moving that | |
6308 | expression to the "beginning" of that block is safe. */ | |
e0082a72 | 6309 | if (!TEST_BIT (antloc[dominated->index], i)) |
bb457bd9 JL |
6310 | continue; |
6311 | ||
6312 | /* The expression is computed in the dominated block and | |
6313 | it would be safe to compute it at the start of the | |
6314 | dominated block. Now we have to determine if the | |
ff7cc307 | 6315 | expression would reach the dominated block if it was |
bb457bd9 | 6316 | placed at the end of BB. */ |
e0082a72 | 6317 | if (hoist_expr_reaches_here_p (bb, i, dominated, NULL)) |
bb457bd9 JL |
6318 | { |
6319 | struct expr *expr = index_map[i]; | |
6320 | struct occr *occr = expr->antic_occr; | |
6321 | rtx insn; | |
6322 | rtx set; | |
6323 | ||
ff7cc307 | 6324 | /* Find the right occurrence of this expression. */ |
e0082a72 | 6325 | while (BLOCK_FOR_INSN (occr->insn) != dominated && occr) |
bb457bd9 JL |
6326 | occr = occr->next; |
6327 | ||
6328 | /* Should never happen. */ | |
6329 | if (!occr) | |
6330 | abort (); | |
6331 | ||
6332 | insn = occr->insn; | |
589005ff | 6333 | |
bb457bd9 JL |
6334 | set = single_set (insn); |
6335 | if (! set) | |
6336 | abort (); | |
6337 | ||
6338 | /* Create a pseudo-reg to store the result of reaching | |
6339 | expressions into. Get the mode for the new pseudo | |
6340 | from the mode of the original destination pseudo. */ | |
6341 | if (expr->reaching_reg == NULL) | |
6342 | expr->reaching_reg | |
6343 | = gen_reg_rtx (GET_MODE (SET_DEST (set))); | |
6344 | ||
10d1bb36 JH |
6345 | gcse_emit_move_after (expr->reaching_reg, SET_DEST (set), insn); |
6346 | delete_insn (insn); | |
6347 | occr->deleted_p = 1; | |
6348 | if (!insn_inserted_p) | |
bb457bd9 | 6349 | { |
10d1bb36 JH |
6350 | insert_insn_end_bb (index_map[i], bb, 0); |
6351 | insn_inserted_p = 1; | |
bb457bd9 JL |
6352 | } |
6353 | } | |
6354 | } | |
6355 | } | |
6356 | } | |
c635a1ec | 6357 | free (domby); |
bb457bd9 | 6358 | } |
c4c81601 | 6359 | |
8e42ace1 | 6360 | free (index_map); |
bb457bd9 JL |
6361 | } |
6362 | ||
6363 | /* Top level routine to perform one code hoisting (aka unification) pass | |
6364 | ||
cc2902df | 6365 | Return nonzero if a change was made. */ |
bb457bd9 JL |
6366 | |
6367 | static int | |
1d088dee | 6368 | one_code_hoisting_pass (void) |
bb457bd9 JL |
6369 | { |
6370 | int changed = 0; | |
6371 | ||
02280659 ZD |
6372 | alloc_hash_table (max_cuid, &expr_hash_table, 0); |
6373 | compute_hash_table (&expr_hash_table); | |
bb457bd9 | 6374 | if (gcse_file) |
02280659 | 6375 | dump_hash_table (gcse_file, "Code Hosting Expressions", &expr_hash_table); |
c4c81601 | 6376 | |
02280659 | 6377 | if (expr_hash_table.n_elems > 0) |
bb457bd9 | 6378 | { |
02280659 | 6379 | alloc_code_hoist_mem (last_basic_block, expr_hash_table.n_elems); |
bb457bd9 JL |
6380 | compute_code_hoist_data (); |
6381 | hoist_code (); | |
6382 | free_code_hoist_mem (); | |
6383 | } | |
c4c81601 | 6384 | |
02280659 | 6385 | free_hash_table (&expr_hash_table); |
bb457bd9 JL |
6386 | |
6387 | return changed; | |
6388 | } | |
a13d4ebf AM |
6389 | \f |
6390 | /* Here we provide the things required to do store motion towards | |
6391 | the exit. In order for this to be effective, gcse also needed to | |
6392 | be taught how to move a load when it is kill only by a store to itself. | |
6393 | ||
6394 | int i; | |
6395 | float a[10]; | |
6396 | ||
6397 | void foo(float scale) | |
6398 | { | |
6399 | for (i=0; i<10; i++) | |
6400 | a[i] *= scale; | |
6401 | } | |
6402 | ||
6403 | 'i' is both loaded and stored to in the loop. Normally, gcse cannot move | |
589005ff KH |
6404 | the load out since its live around the loop, and stored at the bottom |
6405 | of the loop. | |
a13d4ebf | 6406 | |
589005ff | 6407 | The 'Load Motion' referred to and implemented in this file is |
a13d4ebf AM |
6408 | an enhancement to gcse which when using edge based lcm, recognizes |
6409 | this situation and allows gcse to move the load out of the loop. | |
6410 | ||
6411 | Once gcse has hoisted the load, store motion can then push this | |
6412 | load towards the exit, and we end up with no loads or stores of 'i' | |
6413 | in the loop. */ | |
6414 | ||
ff7cc307 | 6415 | /* This will search the ldst list for a matching expression. If it |
a13d4ebf AM |
6416 | doesn't find one, we create one and initialize it. */ |
6417 | ||
6418 | static struct ls_expr * | |
1d088dee | 6419 | ldst_entry (rtx x) |
a13d4ebf AM |
6420 | { |
6421 | struct ls_expr * ptr; | |
6422 | ||
6423 | for (ptr = first_ls_expr(); ptr != NULL; ptr = next_ls_expr (ptr)) | |
6424 | if (expr_equiv_p (ptr->pattern, x)) | |
6425 | break; | |
6426 | ||
6427 | if (!ptr) | |
6428 | { | |
703ad42b | 6429 | ptr = xmalloc (sizeof (struct ls_expr)); |
a13d4ebf AM |
6430 | |
6431 | ptr->next = pre_ldst_mems; | |
6432 | ptr->expr = NULL; | |
6433 | ptr->pattern = x; | |
47a3dae1 | 6434 | ptr->pattern_regs = NULL_RTX; |
a13d4ebf AM |
6435 | ptr->loads = NULL_RTX; |
6436 | ptr->stores = NULL_RTX; | |
6437 | ptr->reaching_reg = NULL_RTX; | |
6438 | ptr->invalid = 0; | |
6439 | ptr->index = 0; | |
6440 | ptr->hash_index = 0; | |
6441 | pre_ldst_mems = ptr; | |
6442 | } | |
589005ff | 6443 | |
a13d4ebf AM |
6444 | return ptr; |
6445 | } | |
6446 | ||
6447 | /* Free up an individual ldst entry. */ | |
6448 | ||
589005ff | 6449 | static void |
1d088dee | 6450 | free_ldst_entry (struct ls_expr * ptr) |
a13d4ebf | 6451 | { |
aaa4ca30 AJ |
6452 | free_INSN_LIST_list (& ptr->loads); |
6453 | free_INSN_LIST_list (& ptr->stores); | |
a13d4ebf AM |
6454 | |
6455 | free (ptr); | |
6456 | } | |
6457 | ||
6458 | /* Free up all memory associated with the ldst list. */ | |
6459 | ||
6460 | static void | |
1d088dee | 6461 | free_ldst_mems (void) |
a13d4ebf | 6462 | { |
589005ff | 6463 | while (pre_ldst_mems) |
a13d4ebf AM |
6464 | { |
6465 | struct ls_expr * tmp = pre_ldst_mems; | |
6466 | ||
6467 | pre_ldst_mems = pre_ldst_mems->next; | |
6468 | ||
6469 | free_ldst_entry (tmp); | |
6470 | } | |
6471 | ||
6472 | pre_ldst_mems = NULL; | |
6473 | } | |
6474 | ||
6475 | /* Dump debugging info about the ldst list. */ | |
6476 | ||
6477 | static void | |
1d088dee | 6478 | print_ldst_list (FILE * file) |
a13d4ebf AM |
6479 | { |
6480 | struct ls_expr * ptr; | |
6481 | ||
6482 | fprintf (file, "LDST list: \n"); | |
6483 | ||
6484 | for (ptr = first_ls_expr(); ptr != NULL; ptr = next_ls_expr (ptr)) | |
6485 | { | |
6486 | fprintf (file, " Pattern (%3d): ", ptr->index); | |
6487 | ||
6488 | print_rtl (file, ptr->pattern); | |
6489 | ||
6490 | fprintf (file, "\n Loads : "); | |
6491 | ||
6492 | if (ptr->loads) | |
6493 | print_rtl (file, ptr->loads); | |
6494 | else | |
6495 | fprintf (file, "(nil)"); | |
6496 | ||
6497 | fprintf (file, "\n Stores : "); | |
6498 | ||
6499 | if (ptr->stores) | |
6500 | print_rtl (file, ptr->stores); | |
6501 | else | |
6502 | fprintf (file, "(nil)"); | |
6503 | ||
6504 | fprintf (file, "\n\n"); | |
6505 | } | |
6506 | ||
6507 | fprintf (file, "\n"); | |
6508 | } | |
6509 | ||
6510 | /* Returns 1 if X is in the list of ldst only expressions. */ | |
6511 | ||
6512 | static struct ls_expr * | |
1d088dee | 6513 | find_rtx_in_ldst (rtx x) |
a13d4ebf AM |
6514 | { |
6515 | struct ls_expr * ptr; | |
589005ff | 6516 | |
a13d4ebf AM |
6517 | for (ptr = pre_ldst_mems; ptr != NULL; ptr = ptr->next) |
6518 | if (expr_equiv_p (ptr->pattern, x) && ! ptr->invalid) | |
6519 | return ptr; | |
6520 | ||
6521 | return NULL; | |
6522 | } | |
6523 | ||
6524 | /* Assign each element of the list of mems a monotonically increasing value. */ | |
6525 | ||
6526 | static int | |
1d088dee | 6527 | enumerate_ldsts (void) |
a13d4ebf AM |
6528 | { |
6529 | struct ls_expr * ptr; | |
6530 | int n = 0; | |
6531 | ||
6532 | for (ptr = pre_ldst_mems; ptr != NULL; ptr = ptr->next) | |
6533 | ptr->index = n++; | |
6534 | ||
6535 | return n; | |
6536 | } | |
6537 | ||
6538 | /* Return first item in the list. */ | |
6539 | ||
6540 | static inline struct ls_expr * | |
1d088dee | 6541 | first_ls_expr (void) |
a13d4ebf AM |
6542 | { |
6543 | return pre_ldst_mems; | |
6544 | } | |
6545 | ||
0e8a66de | 6546 | /* Return the next item in the list after the specified one. */ |
a13d4ebf AM |
6547 | |
6548 | static inline struct ls_expr * | |
1d088dee | 6549 | next_ls_expr (struct ls_expr * ptr) |
a13d4ebf AM |
6550 | { |
6551 | return ptr->next; | |
6552 | } | |
6553 | \f | |
6554 | /* Load Motion for loads which only kill themselves. */ | |
6555 | ||
6556 | /* Return true if x is a simple MEM operation, with no registers or | |
6557 | side effects. These are the types of loads we consider for the | |
6558 | ld_motion list, otherwise we let the usual aliasing take care of it. */ | |
6559 | ||
589005ff | 6560 | static int |
1d088dee | 6561 | simple_mem (rtx x) |
a13d4ebf AM |
6562 | { |
6563 | if (GET_CODE (x) != MEM) | |
6564 | return 0; | |
589005ff | 6565 | |
a13d4ebf AM |
6566 | if (MEM_VOLATILE_P (x)) |
6567 | return 0; | |
589005ff | 6568 | |
a13d4ebf AM |
6569 | if (GET_MODE (x) == BLKmode) |
6570 | return 0; | |
aaa4ca30 | 6571 | |
47a3dae1 ZD |
6572 | /* If we are handling exceptions, we must be careful with memory references |
6573 | that may trap. If we are not, the behavior is undefined, so we may just | |
6574 | continue. */ | |
6575 | if (flag_non_call_exceptions && may_trap_p (x)) | |
98d3d336 RS |
6576 | return 0; |
6577 | ||
47a3dae1 ZD |
6578 | if (side_effects_p (x)) |
6579 | return 0; | |
589005ff | 6580 | |
47a3dae1 ZD |
6581 | /* Do not consider function arguments passed on stack. */ |
6582 | if (reg_mentioned_p (stack_pointer_rtx, x)) | |
6583 | return 0; | |
6584 | ||
6585 | if (flag_float_store && FLOAT_MODE_P (GET_MODE (x))) | |
6586 | return 0; | |
6587 | ||
6588 | return 1; | |
a13d4ebf AM |
6589 | } |
6590 | ||
589005ff KH |
6591 | /* Make sure there isn't a buried reference in this pattern anywhere. |
6592 | If there is, invalidate the entry for it since we're not capable | |
6593 | of fixing it up just yet.. We have to be sure we know about ALL | |
a13d4ebf AM |
6594 | loads since the aliasing code will allow all entries in the |
6595 | ld_motion list to not-alias itself. If we miss a load, we will get | |
589005ff | 6596 | the wrong value since gcse might common it and we won't know to |
a13d4ebf AM |
6597 | fix it up. */ |
6598 | ||
6599 | static void | |
1d088dee | 6600 | invalidate_any_buried_refs (rtx x) |
a13d4ebf AM |
6601 | { |
6602 | const char * fmt; | |
8e42ace1 | 6603 | int i, j; |
a13d4ebf AM |
6604 | struct ls_expr * ptr; |
6605 | ||
6606 | /* Invalidate it in the list. */ | |
6607 | if (GET_CODE (x) == MEM && simple_mem (x)) | |
6608 | { | |
6609 | ptr = ldst_entry (x); | |
6610 | ptr->invalid = 1; | |
6611 | } | |
6612 | ||
6613 | /* Recursively process the insn. */ | |
6614 | fmt = GET_RTX_FORMAT (GET_CODE (x)); | |
589005ff | 6615 | |
a13d4ebf AM |
6616 | for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--) |
6617 | { | |
6618 | if (fmt[i] == 'e') | |
6619 | invalidate_any_buried_refs (XEXP (x, i)); | |
6620 | else if (fmt[i] == 'E') | |
6621 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
6622 | invalidate_any_buried_refs (XVECEXP (x, i, j)); | |
6623 | } | |
6624 | } | |
6625 | ||
4d3eb89a HPN |
6626 | /* Find all the 'simple' MEMs which are used in LOADs and STORES. Simple |
6627 | being defined as MEM loads and stores to symbols, with no side effects | |
6628 | and no registers in the expression. For a MEM destination, we also | |
6629 | check that the insn is still valid if we replace the destination with a | |
6630 | REG, as is done in update_ld_motion_stores. If there are any uses/defs | |
6631 | which don't match this criteria, they are invalidated and trimmed out | |
6632 | later. */ | |
a13d4ebf | 6633 | |
589005ff | 6634 | static void |
1d088dee | 6635 | compute_ld_motion_mems (void) |
a13d4ebf AM |
6636 | { |
6637 | struct ls_expr * ptr; | |
e0082a72 | 6638 | basic_block bb; |
a13d4ebf | 6639 | rtx insn; |
589005ff | 6640 | |
a13d4ebf AM |
6641 | pre_ldst_mems = NULL; |
6642 | ||
e0082a72 | 6643 | FOR_EACH_BB (bb) |
a13d4ebf | 6644 | { |
e0082a72 ZD |
6645 | for (insn = bb->head; |
6646 | insn && insn != NEXT_INSN (bb->end); | |
a13d4ebf AM |
6647 | insn = NEXT_INSN (insn)) |
6648 | { | |
735e8085 | 6649 | if (INSN_P (insn)) |
a13d4ebf AM |
6650 | { |
6651 | if (GET_CODE (PATTERN (insn)) == SET) | |
6652 | { | |
6653 | rtx src = SET_SRC (PATTERN (insn)); | |
6654 | rtx dest = SET_DEST (PATTERN (insn)); | |
6655 | ||
6656 | /* Check for a simple LOAD... */ | |
6657 | if (GET_CODE (src) == MEM && simple_mem (src)) | |
6658 | { | |
6659 | ptr = ldst_entry (src); | |
6660 | if (GET_CODE (dest) == REG) | |
6661 | ptr->loads = alloc_INSN_LIST (insn, ptr->loads); | |
6662 | else | |
6663 | ptr->invalid = 1; | |
6664 | } | |
6665 | else | |
6666 | { | |
6667 | /* Make sure there isn't a buried load somewhere. */ | |
6668 | invalidate_any_buried_refs (src); | |
6669 | } | |
589005ff | 6670 | |
a13d4ebf AM |
6671 | /* Check for stores. Don't worry about aliased ones, they |
6672 | will block any movement we might do later. We only care | |
6673 | about this exact pattern since those are the only | |
6674 | circumstance that we will ignore the aliasing info. */ | |
6675 | if (GET_CODE (dest) == MEM && simple_mem (dest)) | |
6676 | { | |
6677 | ptr = ldst_entry (dest); | |
589005ff | 6678 | |
f54104df | 6679 | if (GET_CODE (src) != MEM |
4d3eb89a HPN |
6680 | && GET_CODE (src) != ASM_OPERANDS |
6681 | /* Check for REG manually since want_to_gcse_p | |
6682 | returns 0 for all REGs. */ | |
6683 | && (REG_P (src) || want_to_gcse_p (src))) | |
a13d4ebf AM |
6684 | ptr->stores = alloc_INSN_LIST (insn, ptr->stores); |
6685 | else | |
6686 | ptr->invalid = 1; | |
6687 | } | |
6688 | } | |
6689 | else | |
6690 | invalidate_any_buried_refs (PATTERN (insn)); | |
6691 | } | |
6692 | } | |
6693 | } | |
6694 | } | |
6695 | ||
589005ff | 6696 | /* Remove any references that have been either invalidated or are not in the |
a13d4ebf AM |
6697 | expression list for pre gcse. */ |
6698 | ||
6699 | static void | |
1d088dee | 6700 | trim_ld_motion_mems (void) |
a13d4ebf AM |
6701 | { |
6702 | struct ls_expr * last = NULL; | |
6703 | struct ls_expr * ptr = first_ls_expr (); | |
6704 | ||
6705 | while (ptr != NULL) | |
6706 | { | |
6707 | int del = ptr->invalid; | |
6708 | struct expr * expr = NULL; | |
589005ff | 6709 | |
a13d4ebf | 6710 | /* Delete if entry has been made invalid. */ |
589005ff | 6711 | if (!del) |
a13d4ebf AM |
6712 | { |
6713 | unsigned int i; | |
589005ff | 6714 | |
a13d4ebf AM |
6715 | del = 1; |
6716 | /* Delete if we cannot find this mem in the expression list. */ | |
02280659 | 6717 | for (i = 0; i < expr_hash_table.size && del; i++) |
a13d4ebf | 6718 | { |
02280659 | 6719 | for (expr = expr_hash_table.table[i]; |
589005ff | 6720 | expr != NULL; |
a13d4ebf AM |
6721 | expr = expr->next_same_hash) |
6722 | if (expr_equiv_p (expr->expr, ptr->pattern)) | |
6723 | { | |
6724 | del = 0; | |
6725 | break; | |
6726 | } | |
6727 | } | |
6728 | } | |
589005ff | 6729 | |
a13d4ebf AM |
6730 | if (del) |
6731 | { | |
6732 | if (last != NULL) | |
6733 | { | |
6734 | last->next = ptr->next; | |
6735 | free_ldst_entry (ptr); | |
6736 | ptr = last->next; | |
6737 | } | |
6738 | else | |
6739 | { | |
6740 | pre_ldst_mems = pre_ldst_mems->next; | |
6741 | free_ldst_entry (ptr); | |
6742 | ptr = pre_ldst_mems; | |
6743 | } | |
6744 | } | |
6745 | else | |
6746 | { | |
6747 | /* Set the expression field if we are keeping it. */ | |
6748 | last = ptr; | |
6749 | ptr->expr = expr; | |
6750 | ptr = ptr->next; | |
6751 | } | |
6752 | } | |
6753 | ||
6754 | /* Show the world what we've found. */ | |
6755 | if (gcse_file && pre_ldst_mems != NULL) | |
6756 | print_ldst_list (gcse_file); | |
6757 | } | |
6758 | ||
6759 | /* This routine will take an expression which we are replacing with | |
6760 | a reaching register, and update any stores that are needed if | |
6761 | that expression is in the ld_motion list. Stores are updated by | |
6762 | copying their SRC to the reaching register, and then storeing | |
6763 | the reaching register into the store location. These keeps the | |
6764 | correct value in the reaching register for the loads. */ | |
6765 | ||
6766 | static void | |
1d088dee | 6767 | update_ld_motion_stores (struct expr * expr) |
a13d4ebf AM |
6768 | { |
6769 | struct ls_expr * mem_ptr; | |
6770 | ||
6771 | if ((mem_ptr = find_rtx_in_ldst (expr->expr))) | |
6772 | { | |
589005ff KH |
6773 | /* We can try to find just the REACHED stores, but is shouldn't |
6774 | matter to set the reaching reg everywhere... some might be | |
a13d4ebf AM |
6775 | dead and should be eliminated later. */ |
6776 | ||
4d3eb89a HPN |
6777 | /* We replace (set mem expr) with (set reg expr) (set mem reg) |
6778 | where reg is the reaching reg used in the load. We checked in | |
6779 | compute_ld_motion_mems that we can replace (set mem expr) with | |
6780 | (set reg expr) in that insn. */ | |
a13d4ebf | 6781 | rtx list = mem_ptr->stores; |
589005ff | 6782 | |
a13d4ebf AM |
6783 | for ( ; list != NULL_RTX; list = XEXP (list, 1)) |
6784 | { | |
6785 | rtx insn = XEXP (list, 0); | |
6786 | rtx pat = PATTERN (insn); | |
6787 | rtx src = SET_SRC (pat); | |
6788 | rtx reg = expr->reaching_reg; | |
c57718d3 | 6789 | rtx copy, new; |
a13d4ebf AM |
6790 | |
6791 | /* If we've already copied it, continue. */ | |
6792 | if (expr->reaching_reg == src) | |
6793 | continue; | |
589005ff | 6794 | |
a13d4ebf AM |
6795 | if (gcse_file) |
6796 | { | |
6797 | fprintf (gcse_file, "PRE: store updated with reaching reg "); | |
6798 | print_rtl (gcse_file, expr->reaching_reg); | |
6799 | fprintf (gcse_file, ":\n "); | |
6800 | print_inline_rtx (gcse_file, insn, 8); | |
6801 | fprintf (gcse_file, "\n"); | |
6802 | } | |
589005ff | 6803 | |
47a3dae1 | 6804 | copy = gen_move_insn ( reg, copy_rtx (SET_SRC (pat))); |
c57718d3 RK |
6805 | new = emit_insn_before (copy, insn); |
6806 | record_one_set (REGNO (reg), new); | |
a13d4ebf AM |
6807 | SET_SRC (pat) = reg; |
6808 | ||
6809 | /* un-recognize this pattern since it's probably different now. */ | |
6810 | INSN_CODE (insn) = -1; | |
6811 | gcse_create_count++; | |
6812 | } | |
6813 | } | |
6814 | } | |
6815 | \f | |
6816 | /* Store motion code. */ | |
6817 | ||
47a3dae1 ZD |
6818 | #define ANTIC_STORE_LIST(x) ((x)->loads) |
6819 | #define AVAIL_STORE_LIST(x) ((x)->stores) | |
6820 | #define LAST_AVAIL_CHECK_FAILURE(x) ((x)->reaching_reg) | |
6821 | ||
589005ff | 6822 | /* This is used to communicate the target bitvector we want to use in the |
aaa4ca30 | 6823 | reg_set_info routine when called via the note_stores mechanism. */ |
47a3dae1 ZD |
6824 | static int * regvec; |
6825 | ||
6826 | /* And current insn, for the same routine. */ | |
6827 | static rtx compute_store_table_current_insn; | |
aaa4ca30 | 6828 | |
a13d4ebf AM |
6829 | /* Used in computing the reverse edge graph bit vectors. */ |
6830 | static sbitmap * st_antloc; | |
6831 | ||
6832 | /* Global holding the number of store expressions we are dealing with. */ | |
6833 | static int num_stores; | |
6834 | ||
aaa4ca30 | 6835 | /* Checks to set if we need to mark a register set. Called from note_stores. */ |
a13d4ebf | 6836 | |
aaa4ca30 | 6837 | static void |
1d088dee AJ |
6838 | reg_set_info (rtx dest, rtx setter ATTRIBUTE_UNUSED, |
6839 | void *data ATTRIBUTE_UNUSED) | |
a13d4ebf | 6840 | { |
aaa4ca30 AJ |
6841 | if (GET_CODE (dest) == SUBREG) |
6842 | dest = SUBREG_REG (dest); | |
adfcce61 | 6843 | |
aaa4ca30 | 6844 | if (GET_CODE (dest) == REG) |
47a3dae1 | 6845 | regvec[REGNO (dest)] = INSN_UID (compute_store_table_current_insn); |
a13d4ebf AM |
6846 | } |
6847 | ||
47a3dae1 ZD |
6848 | /* Return zero if some of the registers in list X are killed |
6849 | due to set of registers in bitmap REGS_SET. */ | |
1d088dee | 6850 | |
47a3dae1 | 6851 | static bool |
1d088dee | 6852 | store_ops_ok (rtx x, int *regs_set) |
47a3dae1 ZD |
6853 | { |
6854 | rtx reg; | |
6855 | ||
6856 | for (; x; x = XEXP (x, 1)) | |
6857 | { | |
6858 | reg = XEXP (x, 0); | |
6859 | if (regs_set[REGNO(reg)]) | |
1d088dee | 6860 | return false; |
47a3dae1 | 6861 | } |
a13d4ebf | 6862 | |
47a3dae1 ZD |
6863 | return true; |
6864 | } | |
6865 | ||
6866 | /* Returns a list of registers mentioned in X. */ | |
6867 | static rtx | |
1d088dee | 6868 | extract_mentioned_regs (rtx x) |
47a3dae1 ZD |
6869 | { |
6870 | return extract_mentioned_regs_helper (x, NULL_RTX); | |
6871 | } | |
6872 | ||
6873 | /* Helper for extract_mentioned_regs; ACCUM is used to accumulate used | |
6874 | registers. */ | |
6875 | static rtx | |
1d088dee | 6876 | extract_mentioned_regs_helper (rtx x, rtx accum) |
a13d4ebf AM |
6877 | { |
6878 | int i; | |
6879 | enum rtx_code code; | |
6880 | const char * fmt; | |
6881 | ||
6882 | /* Repeat is used to turn tail-recursion into iteration. */ | |
6883 | repeat: | |
6884 | ||
6885 | if (x == 0) | |
47a3dae1 | 6886 | return accum; |
a13d4ebf AM |
6887 | |
6888 | code = GET_CODE (x); | |
6889 | switch (code) | |
6890 | { | |
6891 | case REG: | |
47a3dae1 | 6892 | return alloc_EXPR_LIST (0, x, accum); |
a13d4ebf AM |
6893 | |
6894 | case MEM: | |
6895 | x = XEXP (x, 0); | |
6896 | goto repeat; | |
6897 | ||
6898 | case PRE_DEC: | |
6899 | case PRE_INC: | |
6900 | case POST_DEC: | |
6901 | case POST_INC: | |
47a3dae1 ZD |
6902 | /* We do not run this function with arguments having side effects. */ |
6903 | abort (); | |
a13d4ebf AM |
6904 | |
6905 | case PC: | |
6906 | case CC0: /*FIXME*/ | |
6907 | case CONST: | |
6908 | case CONST_INT: | |
6909 | case CONST_DOUBLE: | |
69ef87e2 | 6910 | case CONST_VECTOR: |
a13d4ebf AM |
6911 | case SYMBOL_REF: |
6912 | case LABEL_REF: | |
6913 | case ADDR_VEC: | |
6914 | case ADDR_DIFF_VEC: | |
47a3dae1 | 6915 | return accum; |
a13d4ebf AM |
6916 | |
6917 | default: | |
6918 | break; | |
6919 | } | |
6920 | ||
6921 | i = GET_RTX_LENGTH (code) - 1; | |
6922 | fmt = GET_RTX_FORMAT (code); | |
589005ff | 6923 | |
a13d4ebf AM |
6924 | for (; i >= 0; i--) |
6925 | { | |
6926 | if (fmt[i] == 'e') | |
6927 | { | |
6928 | rtx tem = XEXP (x, i); | |
6929 | ||
6930 | /* If we are about to do the last recursive call | |
47a3dae1 | 6931 | needed at this level, change it into iteration. */ |
a13d4ebf AM |
6932 | if (i == 0) |
6933 | { | |
6934 | x = tem; | |
6935 | goto repeat; | |
6936 | } | |
589005ff | 6937 | |
47a3dae1 | 6938 | accum = extract_mentioned_regs_helper (tem, accum); |
a13d4ebf AM |
6939 | } |
6940 | else if (fmt[i] == 'E') | |
6941 | { | |
6942 | int j; | |
589005ff | 6943 | |
a13d4ebf | 6944 | for (j = 0; j < XVECLEN (x, i); j++) |
47a3dae1 | 6945 | accum = extract_mentioned_regs_helper (XVECEXP (x, i, j), accum); |
a13d4ebf AM |
6946 | } |
6947 | } | |
6948 | ||
47a3dae1 | 6949 | return accum; |
a13d4ebf AM |
6950 | } |
6951 | ||
47a3dae1 ZD |
6952 | /* Determine whether INSN is MEM store pattern that we will consider moving. |
6953 | REGS_SET_BEFORE is bitmap of registers set before (and including) the | |
6954 | current insn, REGS_SET_AFTER is bitmap of registers set after (and | |
6955 | including) the insn in this basic block. We must be passing through BB from | |
6956 | head to end, as we are using this fact to speed things up. | |
1d088dee | 6957 | |
47a3dae1 ZD |
6958 | The results are stored this way: |
6959 | ||
6960 | -- the first anticipatable expression is added into ANTIC_STORE_LIST | |
6961 | -- if the processed expression is not anticipatable, NULL_RTX is added | |
6962 | there instead, so that we can use it as indicator that no further | |
6963 | expression of this type may be anticipatable | |
6964 | -- if the expression is available, it is added as head of AVAIL_STORE_LIST; | |
6965 | consequently, all of them but this head are dead and may be deleted. | |
6966 | -- if the expression is not available, the insn due to that it fails to be | |
6967 | available is stored in reaching_reg. | |
6968 | ||
6969 | The things are complicated a bit by fact that there already may be stores | |
6970 | to the same MEM from other blocks; also caller must take care of the | |
e0bb17a8 | 6971 | necessary cleanup of the temporary markers after end of the basic block. |
47a3dae1 | 6972 | */ |
a13d4ebf AM |
6973 | |
6974 | static void | |
1d088dee | 6975 | find_moveable_store (rtx insn, int *regs_set_before, int *regs_set_after) |
a13d4ebf AM |
6976 | { |
6977 | struct ls_expr * ptr; | |
47a3dae1 ZD |
6978 | rtx dest, set, tmp; |
6979 | int check_anticipatable, check_available; | |
6980 | basic_block bb = BLOCK_FOR_INSN (insn); | |
a13d4ebf | 6981 | |
47a3dae1 ZD |
6982 | set = single_set (insn); |
6983 | if (!set) | |
a13d4ebf AM |
6984 | return; |
6985 | ||
47a3dae1 | 6986 | dest = SET_DEST (set); |
589005ff | 6987 | |
a13d4ebf AM |
6988 | if (GET_CODE (dest) != MEM || MEM_VOLATILE_P (dest) |
6989 | || GET_MODE (dest) == BLKmode) | |
aaa4ca30 AJ |
6990 | return; |
6991 | ||
47a3dae1 ZD |
6992 | if (side_effects_p (dest)) |
6993 | return; | |
aaa4ca30 | 6994 | |
47a3dae1 ZD |
6995 | /* If we are handling exceptions, we must be careful with memory references |
6996 | that may trap. If we are not, the behavior is undefined, so we may just | |
6997 | continue. */ | |
94f24ddc | 6998 | if (flag_non_call_exceptions && may_trap_p (dest)) |
47a3dae1 | 6999 | return; |
1d088dee | 7000 | |
a13d4ebf | 7001 | ptr = ldst_entry (dest); |
47a3dae1 ZD |
7002 | if (!ptr->pattern_regs) |
7003 | ptr->pattern_regs = extract_mentioned_regs (dest); | |
7004 | ||
7005 | /* Do not check for anticipatability if we either found one anticipatable | |
7006 | store already, or tested for one and found out that it was killed. */ | |
7007 | check_anticipatable = 0; | |
7008 | if (!ANTIC_STORE_LIST (ptr)) | |
7009 | check_anticipatable = 1; | |
7010 | else | |
7011 | { | |
7012 | tmp = XEXP (ANTIC_STORE_LIST (ptr), 0); | |
7013 | if (tmp != NULL_RTX | |
7014 | && BLOCK_FOR_INSN (tmp) != bb) | |
7015 | check_anticipatable = 1; | |
7016 | } | |
7017 | if (check_anticipatable) | |
7018 | { | |
7019 | if (store_killed_before (dest, ptr->pattern_regs, insn, bb, regs_set_before)) | |
7020 | tmp = NULL_RTX; | |
7021 | else | |
7022 | tmp = insn; | |
7023 | ANTIC_STORE_LIST (ptr) = alloc_INSN_LIST (tmp, | |
7024 | ANTIC_STORE_LIST (ptr)); | |
7025 | } | |
a13d4ebf | 7026 | |
e0bb17a8 | 7027 | /* It is not necessary to check whether store is available if we did |
47a3dae1 ZD |
7028 | it successfully before; if we failed before, do not bother to check |
7029 | until we reach the insn that caused us to fail. */ | |
7030 | check_available = 0; | |
7031 | if (!AVAIL_STORE_LIST (ptr)) | |
7032 | check_available = 1; | |
7033 | else | |
7034 | { | |
7035 | tmp = XEXP (AVAIL_STORE_LIST (ptr), 0); | |
7036 | if (BLOCK_FOR_INSN (tmp) != bb) | |
7037 | check_available = 1; | |
7038 | } | |
7039 | if (check_available) | |
7040 | { | |
7041 | /* Check that we have already reached the insn at that the check | |
7042 | failed last time. */ | |
7043 | if (LAST_AVAIL_CHECK_FAILURE (ptr)) | |
7044 | { | |
7045 | for (tmp = bb->end; | |
7046 | tmp != insn && tmp != LAST_AVAIL_CHECK_FAILURE (ptr); | |
7047 | tmp = PREV_INSN (tmp)) | |
7048 | continue; | |
7049 | if (tmp == insn) | |
7050 | check_available = 0; | |
7051 | } | |
7052 | else | |
7053 | check_available = store_killed_after (dest, ptr->pattern_regs, insn, | |
7054 | bb, regs_set_after, | |
7055 | &LAST_AVAIL_CHECK_FAILURE (ptr)); | |
7056 | } | |
7057 | if (!check_available) | |
7058 | AVAIL_STORE_LIST (ptr) = alloc_INSN_LIST (insn, AVAIL_STORE_LIST (ptr)); | |
7059 | } | |
1d088dee | 7060 | |
47a3dae1 | 7061 | /* Find available and anticipatable stores. */ |
a13d4ebf AM |
7062 | |
7063 | static int | |
1d088dee | 7064 | compute_store_table (void) |
a13d4ebf | 7065 | { |
e0082a72 ZD |
7066 | int ret; |
7067 | basic_block bb; | |
aaa4ca30 | 7068 | unsigned regno; |
47a3dae1 ZD |
7069 | rtx insn, pat, tmp; |
7070 | int *last_set_in, *already_set; | |
7071 | struct ls_expr * ptr, **prev_next_ptr_ptr; | |
aaa4ca30 | 7072 | |
a13d4ebf AM |
7073 | max_gcse_regno = max_reg_num (); |
7074 | ||
703ad42b | 7075 | reg_set_in_block = sbitmap_vector_alloc (last_basic_block, |
aaa4ca30 | 7076 | max_gcse_regno); |
d55bc081 | 7077 | sbitmap_vector_zero (reg_set_in_block, last_basic_block); |
a13d4ebf | 7078 | pre_ldst_mems = 0; |
47a3dae1 ZD |
7079 | last_set_in = xmalloc (sizeof (int) * max_gcse_regno); |
7080 | already_set = xmalloc (sizeof (int) * max_gcse_regno); | |
aaa4ca30 | 7081 | |
a13d4ebf | 7082 | /* Find all the stores we care about. */ |
e0082a72 | 7083 | FOR_EACH_BB (bb) |
a13d4ebf | 7084 | { |
47a3dae1 ZD |
7085 | /* First compute the registers set in this block. */ |
7086 | memset (last_set_in, 0, sizeof (int) * max_gcse_regno); | |
7087 | regvec = last_set_in; | |
7088 | ||
7089 | for (insn = bb->head; | |
7090 | insn != NEXT_INSN (bb->end); | |
7091 | insn = NEXT_INSN (insn)) | |
7092 | { | |
7093 | if (! INSN_P (insn)) | |
7094 | continue; | |
7095 | ||
7096 | if (GET_CODE (insn) == CALL_INSN) | |
7097 | { | |
7098 | bool clobbers_all = false; | |
7099 | #ifdef NON_SAVING_SETJMP | |
7100 | if (NON_SAVING_SETJMP | |
7101 | && find_reg_note (insn, REG_SETJMP, NULL_RTX)) | |
7102 | clobbers_all = true; | |
7103 | #endif | |
7104 | ||
7105 | for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) | |
7106 | if (clobbers_all | |
7107 | || TEST_HARD_REG_BIT (regs_invalidated_by_call, regno)) | |
7108 | last_set_in[regno] = INSN_UID (insn); | |
7109 | } | |
7110 | ||
7111 | pat = PATTERN (insn); | |
7112 | compute_store_table_current_insn = insn; | |
7113 | note_stores (pat, reg_set_info, NULL); | |
7114 | } | |
7115 | ||
7116 | /* Record the set registers. */ | |
7117 | for (regno = 0; regno < max_gcse_regno; regno++) | |
7118 | if (last_set_in[regno]) | |
7119 | SET_BIT (reg_set_in_block[bb->index], regno); | |
7120 | ||
7121 | /* Now find the stores. */ | |
7122 | memset (already_set, 0, sizeof (int) * max_gcse_regno); | |
7123 | regvec = already_set; | |
7124 | for (insn = bb->head; | |
7125 | insn != NEXT_INSN (bb->end); | |
7126 | insn = NEXT_INSN (insn)) | |
a13d4ebf | 7127 | { |
19652adf | 7128 | if (! INSN_P (insn)) |
a13d4ebf AM |
7129 | continue; |
7130 | ||
aaa4ca30 AJ |
7131 | if (GET_CODE (insn) == CALL_INSN) |
7132 | { | |
19652adf | 7133 | bool clobbers_all = false; |
589005ff | 7134 | #ifdef NON_SAVING_SETJMP |
19652adf ZW |
7135 | if (NON_SAVING_SETJMP |
7136 | && find_reg_note (insn, REG_SETJMP, NULL_RTX)) | |
7137 | clobbers_all = true; | |
7138 | #endif | |
7139 | ||
aaa4ca30 | 7140 | for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) |
19652adf ZW |
7141 | if (clobbers_all |
7142 | || TEST_HARD_REG_BIT (regs_invalidated_by_call, regno)) | |
47a3dae1 | 7143 | already_set[regno] = 1; |
aaa4ca30 | 7144 | } |
589005ff | 7145 | |
a13d4ebf | 7146 | pat = PATTERN (insn); |
aaa4ca30 | 7147 | note_stores (pat, reg_set_info, NULL); |
589005ff | 7148 | |
a13d4ebf | 7149 | /* Now that we've marked regs, look for stores. */ |
47a3dae1 ZD |
7150 | find_moveable_store (insn, already_set, last_set_in); |
7151 | ||
7152 | /* Unmark regs that are no longer set. */ | |
7153 | for (regno = 0; regno < max_gcse_regno; regno++) | |
7154 | if (last_set_in[regno] == INSN_UID (insn)) | |
7155 | last_set_in[regno] = 0; | |
7156 | } | |
7157 | ||
7158 | /* Clear temporary marks. */ | |
7159 | for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr)) | |
7160 | { | |
7161 | LAST_AVAIL_CHECK_FAILURE(ptr) = NULL_RTX; | |
7162 | if (ANTIC_STORE_LIST (ptr) | |
7163 | && (tmp = XEXP (ANTIC_STORE_LIST (ptr), 0)) == NULL_RTX) | |
7164 | ANTIC_STORE_LIST (ptr) = XEXP (ANTIC_STORE_LIST (ptr), 1); | |
7165 | } | |
7166 | } | |
7167 | ||
7168 | /* Remove the stores that are not available anywhere, as there will | |
7169 | be no opportunity to optimize them. */ | |
7170 | for (ptr = pre_ldst_mems, prev_next_ptr_ptr = &pre_ldst_mems; | |
7171 | ptr != NULL; | |
7172 | ptr = *prev_next_ptr_ptr) | |
7173 | { | |
7174 | if (!AVAIL_STORE_LIST (ptr)) | |
7175 | { | |
7176 | *prev_next_ptr_ptr = ptr->next; | |
7177 | free_ldst_entry (ptr); | |
a13d4ebf | 7178 | } |
47a3dae1 ZD |
7179 | else |
7180 | prev_next_ptr_ptr = &ptr->next; | |
a13d4ebf AM |
7181 | } |
7182 | ||
7183 | ret = enumerate_ldsts (); | |
589005ff | 7184 | |
a13d4ebf AM |
7185 | if (gcse_file) |
7186 | { | |
47a3dae1 | 7187 | fprintf (gcse_file, "ST_avail and ST_antic (shown under loads..)\n"); |
a13d4ebf AM |
7188 | print_ldst_list (gcse_file); |
7189 | } | |
589005ff | 7190 | |
47a3dae1 ZD |
7191 | free (last_set_in); |
7192 | free (already_set); | |
a13d4ebf AM |
7193 | return ret; |
7194 | } | |
7195 | ||
3b14e3af ZD |
7196 | /* Check to see if the load X is aliased with STORE_PATTERN. |
7197 | AFTER is true if we are checking the case when STORE_PATTERN occurs | |
7198 | after the X. */ | |
a13d4ebf | 7199 | |
47a3dae1 | 7200 | static bool |
3b14e3af | 7201 | load_kills_store (rtx x, rtx store_pattern, int after) |
a13d4ebf | 7202 | { |
3b14e3af ZD |
7203 | if (after) |
7204 | return anti_dependence (x, store_pattern); | |
7205 | else | |
7206 | return true_dependence (store_pattern, GET_MODE (store_pattern), x, | |
7207 | rtx_addr_varies_p); | |
a13d4ebf AM |
7208 | } |
7209 | ||
589005ff | 7210 | /* Go through the entire insn X, looking for any loads which might alias |
3b14e3af ZD |
7211 | STORE_PATTERN. Return true if found. |
7212 | AFTER is true if we are checking the case when STORE_PATTERN occurs | |
7213 | after the insn X. */ | |
a13d4ebf | 7214 | |
47a3dae1 | 7215 | static bool |
3b14e3af | 7216 | find_loads (rtx x, rtx store_pattern, int after) |
a13d4ebf AM |
7217 | { |
7218 | const char * fmt; | |
8e42ace1 | 7219 | int i, j; |
47a3dae1 | 7220 | int ret = false; |
a13d4ebf | 7221 | |
24a28584 | 7222 | if (!x) |
47a3dae1 | 7223 | return false; |
24a28584 | 7224 | |
589005ff | 7225 | if (GET_CODE (x) == SET) |
a13d4ebf AM |
7226 | x = SET_SRC (x); |
7227 | ||
7228 | if (GET_CODE (x) == MEM) | |
7229 | { | |
3b14e3af | 7230 | if (load_kills_store (x, store_pattern, after)) |
47a3dae1 | 7231 | return true; |
a13d4ebf AM |
7232 | } |
7233 | ||
7234 | /* Recursively process the insn. */ | |
7235 | fmt = GET_RTX_FORMAT (GET_CODE (x)); | |
589005ff | 7236 | |
a13d4ebf AM |
7237 | for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0 && !ret; i--) |
7238 | { | |
7239 | if (fmt[i] == 'e') | |
3b14e3af | 7240 | ret |= find_loads (XEXP (x, i), store_pattern, after); |
a13d4ebf AM |
7241 | else if (fmt[i] == 'E') |
7242 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) | |
3b14e3af | 7243 | ret |= find_loads (XVECEXP (x, i, j), store_pattern, after); |
a13d4ebf AM |
7244 | } |
7245 | return ret; | |
7246 | } | |
7247 | ||
589005ff | 7248 | /* Check if INSN kills the store pattern X (is aliased with it). |
3b14e3af ZD |
7249 | AFTER is true if we are checking the case when store X occurs |
7250 | after the insn. Return true if it it does. */ | |
a13d4ebf | 7251 | |
47a3dae1 | 7252 | static bool |
3b14e3af | 7253 | store_killed_in_insn (rtx x, rtx x_regs, rtx insn, int after) |
a13d4ebf | 7254 | { |
94f24ddc ZD |
7255 | rtx reg, base; |
7256 | ||
735e8085 | 7257 | if (!INSN_P (insn)) |
47a3dae1 | 7258 | return false; |
589005ff | 7259 | |
a13d4ebf AM |
7260 | if (GET_CODE (insn) == CALL_INSN) |
7261 | { | |
1218665b JJ |
7262 | /* A normal or pure call might read from pattern, |
7263 | but a const call will not. */ | |
47a3dae1 ZD |
7264 | if (! CONST_OR_PURE_CALL_P (insn) || pure_call_p (insn)) |
7265 | return true; | |
7266 | ||
94f24ddc ZD |
7267 | /* But even a const call reads its parameters. Check whether the |
7268 | base of some of registers used in mem is stack pointer. */ | |
7269 | for (reg = x_regs; reg; reg = XEXP (reg, 1)) | |
7270 | { | |
bc083e18 | 7271 | base = find_base_term (XEXP (reg, 0)); |
94f24ddc ZD |
7272 | if (!base |
7273 | || (GET_CODE (base) == ADDRESS | |
7274 | && GET_MODE (base) == Pmode | |
7275 | && XEXP (base, 0) == stack_pointer_rtx)) | |
7276 | return true; | |
7277 | } | |
47a3dae1 ZD |
7278 | |
7279 | return false; | |
a13d4ebf | 7280 | } |
589005ff | 7281 | |
a13d4ebf AM |
7282 | if (GET_CODE (PATTERN (insn)) == SET) |
7283 | { | |
7284 | rtx pat = PATTERN (insn); | |
3b14e3af ZD |
7285 | rtx dest = SET_DEST (pat); |
7286 | ||
7287 | if (GET_CODE (dest) == SIGN_EXTRACT | |
7288 | || GET_CODE (dest) == ZERO_EXTRACT) | |
7289 | dest = XEXP (dest, 0); | |
7290 | ||
a13d4ebf | 7291 | /* Check for memory stores to aliased objects. */ |
3b14e3af ZD |
7292 | if (GET_CODE (dest) == MEM |
7293 | && !expr_equiv_p (dest, x)) | |
7294 | { | |
7295 | if (after) | |
7296 | { | |
7297 | if (output_dependence (dest, x)) | |
7298 | return true; | |
7299 | } | |
7300 | else | |
7301 | { | |
7302 | if (output_dependence (x, dest)) | |
7303 | return true; | |
7304 | } | |
7305 | } | |
7306 | return find_loads (SET_SRC (pat), x, after); | |
a13d4ebf AM |
7307 | } |
7308 | else | |
3b14e3af | 7309 | return find_loads (PATTERN (insn), x, after); |
a13d4ebf AM |
7310 | } |
7311 | ||
47a3dae1 ZD |
7312 | /* Returns true if the expression X is loaded or clobbered on or after INSN |
7313 | within basic block BB. REGS_SET_AFTER is bitmap of registers set in | |
7314 | or after the insn. X_REGS is list of registers mentioned in X. If the store | |
7315 | is killed, return the last insn in that it occurs in FAIL_INSN. */ | |
a13d4ebf | 7316 | |
47a3dae1 | 7317 | static bool |
1d088dee AJ |
7318 | store_killed_after (rtx x, rtx x_regs, rtx insn, basic_block bb, |
7319 | int *regs_set_after, rtx *fail_insn) | |
a13d4ebf | 7320 | { |
47a3dae1 | 7321 | rtx last = bb->end, act; |
aaa4ca30 | 7322 | |
47a3dae1 | 7323 | if (!store_ops_ok (x_regs, regs_set_after)) |
1d088dee | 7324 | { |
47a3dae1 ZD |
7325 | /* We do not know where it will happen. */ |
7326 | if (fail_insn) | |
7327 | *fail_insn = NULL_RTX; | |
7328 | return true; | |
7329 | } | |
a13d4ebf | 7330 | |
47a3dae1 ZD |
7331 | /* Scan from the end, so that fail_insn is determined correctly. */ |
7332 | for (act = last; act != PREV_INSN (insn); act = PREV_INSN (act)) | |
3b14e3af | 7333 | if (store_killed_in_insn (x, x_regs, act, false)) |
47a3dae1 ZD |
7334 | { |
7335 | if (fail_insn) | |
7336 | *fail_insn = act; | |
7337 | return true; | |
7338 | } | |
589005ff | 7339 | |
47a3dae1 | 7340 | return false; |
a13d4ebf | 7341 | } |
1d088dee | 7342 | |
47a3dae1 ZD |
7343 | /* Returns true if the expression X is loaded or clobbered on or before INSN |
7344 | within basic block BB. X_REGS is list of registers mentioned in X. | |
7345 | REGS_SET_BEFORE is bitmap of registers set before or in this insn. */ | |
7346 | static bool | |
1d088dee AJ |
7347 | store_killed_before (rtx x, rtx x_regs, rtx insn, basic_block bb, |
7348 | int *regs_set_before) | |
a13d4ebf | 7349 | { |
8e42ace1 | 7350 | rtx first = bb->head; |
a13d4ebf | 7351 | |
47a3dae1 ZD |
7352 | if (!store_ops_ok (x_regs, regs_set_before)) |
7353 | return true; | |
a13d4ebf | 7354 | |
47a3dae1 | 7355 | for ( ; insn != PREV_INSN (first); insn = PREV_INSN (insn)) |
3b14e3af | 7356 | if (store_killed_in_insn (x, x_regs, insn, true)) |
47a3dae1 | 7357 | return true; |
589005ff | 7358 | |
47a3dae1 | 7359 | return false; |
a13d4ebf | 7360 | } |
1d088dee | 7361 | |
47a3dae1 ZD |
7362 | /* Fill in available, anticipatable, transparent and kill vectors in |
7363 | STORE_DATA, based on lists of available and anticipatable stores. */ | |
a13d4ebf | 7364 | static void |
1d088dee | 7365 | build_store_vectors (void) |
a13d4ebf | 7366 | { |
47a3dae1 ZD |
7367 | basic_block bb; |
7368 | int *regs_set_in_block; | |
a13d4ebf AM |
7369 | rtx insn, st; |
7370 | struct ls_expr * ptr; | |
47a3dae1 | 7371 | unsigned regno; |
a13d4ebf AM |
7372 | |
7373 | /* Build the gen_vector. This is any store in the table which is not killed | |
7374 | by aliasing later in its block. */ | |
703ad42b | 7375 | ae_gen = sbitmap_vector_alloc (last_basic_block, num_stores); |
d55bc081 | 7376 | sbitmap_vector_zero (ae_gen, last_basic_block); |
a13d4ebf | 7377 | |
703ad42b | 7378 | st_antloc = sbitmap_vector_alloc (last_basic_block, num_stores); |
d55bc081 | 7379 | sbitmap_vector_zero (st_antloc, last_basic_block); |
aaa4ca30 | 7380 | |
a13d4ebf | 7381 | for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr)) |
589005ff | 7382 | { |
47a3dae1 | 7383 | for (st = AVAIL_STORE_LIST (ptr); st != NULL; st = XEXP (st, 1)) |
a13d4ebf AM |
7384 | { |
7385 | insn = XEXP (st, 0); | |
e2d2ed72 | 7386 | bb = BLOCK_FOR_INSN (insn); |
589005ff | 7387 | |
47a3dae1 ZD |
7388 | /* If we've already seen an available expression in this block, |
7389 | we can delete this one (It occurs earlier in the block). We'll | |
7390 | copy the SRC expression to an unused register in case there | |
7391 | are any side effects. */ | |
7392 | if (TEST_BIT (ae_gen[bb->index], ptr->index)) | |
a13d4ebf | 7393 | { |
47a3dae1 ZD |
7394 | rtx r = gen_reg_rtx (GET_MODE (ptr->pattern)); |
7395 | if (gcse_file) | |
7396 | fprintf (gcse_file, "Removing redundant store:\n"); | |
7397 | replace_store_insn (r, XEXP (st, 0), bb); | |
7398 | continue; | |
a13d4ebf | 7399 | } |
47a3dae1 | 7400 | SET_BIT (ae_gen[bb->index], ptr->index); |
a13d4ebf | 7401 | } |
589005ff | 7402 | |
47a3dae1 ZD |
7403 | for (st = ANTIC_STORE_LIST (ptr); st != NULL; st = XEXP (st, 1)) |
7404 | { | |
7405 | insn = XEXP (st, 0); | |
7406 | bb = BLOCK_FOR_INSN (insn); | |
7407 | SET_BIT (st_antloc[bb->index], ptr->index); | |
7408 | } | |
a13d4ebf | 7409 | } |
589005ff | 7410 | |
703ad42b | 7411 | ae_kill = sbitmap_vector_alloc (last_basic_block, num_stores); |
d55bc081 | 7412 | sbitmap_vector_zero (ae_kill, last_basic_block); |
a13d4ebf | 7413 | |
703ad42b | 7414 | transp = sbitmap_vector_alloc (last_basic_block, num_stores); |
d55bc081 | 7415 | sbitmap_vector_zero (transp, last_basic_block); |
47a3dae1 | 7416 | regs_set_in_block = xmalloc (sizeof (int) * max_gcse_regno); |
a13d4ebf | 7417 | |
47a3dae1 ZD |
7418 | FOR_EACH_BB (bb) |
7419 | { | |
7420 | for (regno = 0; regno < max_gcse_regno; regno++) | |
7421 | regs_set_in_block[regno] = TEST_BIT (reg_set_in_block[bb->index], regno); | |
7422 | ||
7423 | for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr)) | |
7424 | { | |
7425 | if (store_killed_after (ptr->pattern, ptr->pattern_regs, bb->head, | |
7426 | bb, regs_set_in_block, NULL)) | |
7427 | { | |
e0bb17a8 | 7428 | /* It should not be necessary to consider the expression |
47a3dae1 ZD |
7429 | killed if it is both anticipatable and available. */ |
7430 | if (!TEST_BIT (st_antloc[bb->index], ptr->index) | |
7431 | || !TEST_BIT (ae_gen[bb->index], ptr->index)) | |
7432 | SET_BIT (ae_kill[bb->index], ptr->index); | |
1d088dee AJ |
7433 | } |
7434 | else | |
7435 | SET_BIT (transp[bb->index], ptr->index); | |
7436 | } | |
47a3dae1 ZD |
7437 | } |
7438 | ||
7439 | free (regs_set_in_block); | |
aaa4ca30 | 7440 | |
589005ff | 7441 | if (gcse_file) |
aaa4ca30 | 7442 | { |
d55bc081 ZD |
7443 | dump_sbitmap_vector (gcse_file, "st_antloc", "", st_antloc, last_basic_block); |
7444 | dump_sbitmap_vector (gcse_file, "st_kill", "", ae_kill, last_basic_block); | |
7445 | dump_sbitmap_vector (gcse_file, "Transpt", "", transp, last_basic_block); | |
7446 | dump_sbitmap_vector (gcse_file, "st_avloc", "", ae_gen, last_basic_block); | |
a13d4ebf AM |
7447 | } |
7448 | } | |
7449 | ||
fbe5a4a6 | 7450 | /* Insert an instruction at the beginning of a basic block, and update |
a13d4ebf AM |
7451 | the BLOCK_HEAD if needed. */ |
7452 | ||
589005ff | 7453 | static void |
1d088dee | 7454 | insert_insn_start_bb (rtx insn, basic_block bb) |
a13d4ebf AM |
7455 | { |
7456 | /* Insert at start of successor block. */ | |
e2d2ed72 AM |
7457 | rtx prev = PREV_INSN (bb->head); |
7458 | rtx before = bb->head; | |
a13d4ebf AM |
7459 | while (before != 0) |
7460 | { | |
7461 | if (GET_CODE (before) != CODE_LABEL | |
7462 | && (GET_CODE (before) != NOTE | |
7463 | || NOTE_LINE_NUMBER (before) != NOTE_INSN_BASIC_BLOCK)) | |
7464 | break; | |
7465 | prev = before; | |
e2d2ed72 | 7466 | if (prev == bb->end) |
a13d4ebf AM |
7467 | break; |
7468 | before = NEXT_INSN (before); | |
7469 | } | |
7470 | ||
7471 | insn = emit_insn_after (insn, prev); | |
7472 | ||
a13d4ebf AM |
7473 | if (gcse_file) |
7474 | { | |
7475 | fprintf (gcse_file, "STORE_MOTION insert store at start of BB %d:\n", | |
0b17ab2f | 7476 | bb->index); |
a13d4ebf AM |
7477 | print_inline_rtx (gcse_file, insn, 6); |
7478 | fprintf (gcse_file, "\n"); | |
7479 | } | |
7480 | } | |
7481 | ||
7482 | /* This routine will insert a store on an edge. EXPR is the ldst entry for | |
cc2902df | 7483 | the memory reference, and E is the edge to insert it on. Returns nonzero |
a13d4ebf AM |
7484 | if an edge insertion was performed. */ |
7485 | ||
7486 | static int | |
1d088dee | 7487 | insert_store (struct ls_expr * expr, edge e) |
a13d4ebf AM |
7488 | { |
7489 | rtx reg, insn; | |
e2d2ed72 | 7490 | basic_block bb; |
a13d4ebf AM |
7491 | edge tmp; |
7492 | ||
7493 | /* We did all the deleted before this insert, so if we didn't delete a | |
7494 | store, then we haven't set the reaching reg yet either. */ | |
7495 | if (expr->reaching_reg == NULL_RTX) | |
7496 | return 0; | |
7497 | ||
7498 | reg = expr->reaching_reg; | |
47a3dae1 | 7499 | insn = gen_move_insn (copy_rtx (expr->pattern), reg); |
589005ff | 7500 | |
a13d4ebf AM |
7501 | /* If we are inserting this expression on ALL predecessor edges of a BB, |
7502 | insert it at the start of the BB, and reset the insert bits on the other | |
ff7cc307 | 7503 | edges so we don't try to insert it on the other edges. */ |
e2d2ed72 | 7504 | bb = e->dest; |
a13d4ebf AM |
7505 | for (tmp = e->dest->pred; tmp ; tmp = tmp->pred_next) |
7506 | { | |
7507 | int index = EDGE_INDEX (edge_list, tmp->src, tmp->dest); | |
7508 | if (index == EDGE_INDEX_NO_EDGE) | |
7509 | abort (); | |
7510 | if (! TEST_BIT (pre_insert_map[index], expr->index)) | |
7511 | break; | |
7512 | } | |
7513 | ||
7514 | /* If tmp is NULL, we found an insertion on every edge, blank the | |
7515 | insertion vector for these edges, and insert at the start of the BB. */ | |
e2d2ed72 | 7516 | if (!tmp && bb != EXIT_BLOCK_PTR) |
a13d4ebf AM |
7517 | { |
7518 | for (tmp = e->dest->pred; tmp ; tmp = tmp->pred_next) | |
7519 | { | |
7520 | int index = EDGE_INDEX (edge_list, tmp->src, tmp->dest); | |
7521 | RESET_BIT (pre_insert_map[index], expr->index); | |
7522 | } | |
7523 | insert_insn_start_bb (insn, bb); | |
7524 | return 0; | |
7525 | } | |
589005ff | 7526 | |
a13d4ebf AM |
7527 | /* We can't insert on this edge, so we'll insert at the head of the |
7528 | successors block. See Morgan, sec 10.5. */ | |
7529 | if ((e->flags & EDGE_ABNORMAL) == EDGE_ABNORMAL) | |
7530 | { | |
7531 | insert_insn_start_bb (insn, bb); | |
7532 | return 0; | |
7533 | } | |
7534 | ||
7535 | insert_insn_on_edge (insn, e); | |
589005ff | 7536 | |
a13d4ebf AM |
7537 | if (gcse_file) |
7538 | { | |
7539 | fprintf (gcse_file, "STORE_MOTION insert insn on edge (%d, %d):\n", | |
0b17ab2f | 7540 | e->src->index, e->dest->index); |
a13d4ebf AM |
7541 | print_inline_rtx (gcse_file, insn, 6); |
7542 | fprintf (gcse_file, "\n"); | |
7543 | } | |
589005ff | 7544 | |
a13d4ebf AM |
7545 | return 1; |
7546 | } | |
7547 | ||
7548 | /* This routine will replace a store with a SET to a specified register. */ | |
7549 | ||
7550 | static void | |
1d088dee | 7551 | replace_store_insn (rtx reg, rtx del, basic_block bb) |
a13d4ebf AM |
7552 | { |
7553 | rtx insn; | |
589005ff | 7554 | |
9a318d30 | 7555 | insn = gen_move_insn (reg, SET_SRC (single_set (del))); |
a13d4ebf | 7556 | insn = emit_insn_after (insn, del); |
589005ff | 7557 | |
a13d4ebf AM |
7558 | if (gcse_file) |
7559 | { | |
589005ff | 7560 | fprintf (gcse_file, |
0b17ab2f | 7561 | "STORE_MOTION delete insn in BB %d:\n ", bb->index); |
a13d4ebf | 7562 | print_inline_rtx (gcse_file, del, 6); |
8e42ace1 | 7563 | fprintf (gcse_file, "\nSTORE MOTION replaced with insn:\n "); |
a13d4ebf | 7564 | print_inline_rtx (gcse_file, insn, 6); |
8e42ace1 | 7565 | fprintf (gcse_file, "\n"); |
a13d4ebf | 7566 | } |
589005ff | 7567 | |
49ce134f | 7568 | delete_insn (del); |
a13d4ebf AM |
7569 | } |
7570 | ||
7571 | ||
7572 | /* Delete a store, but copy the value that would have been stored into | |
7573 | the reaching_reg for later storing. */ | |
7574 | ||
7575 | static void | |
1d088dee | 7576 | delete_store (struct ls_expr * expr, basic_block bb) |
a13d4ebf AM |
7577 | { |
7578 | rtx reg, i, del; | |
7579 | ||
7580 | if (expr->reaching_reg == NULL_RTX) | |
7581 | expr->reaching_reg = gen_reg_rtx (GET_MODE (expr->pattern)); | |
a13d4ebf | 7582 | |
a13d4ebf | 7583 | reg = expr->reaching_reg; |
589005ff | 7584 | |
a13d4ebf AM |
7585 | for (i = AVAIL_STORE_LIST (expr); i; i = XEXP (i, 1)) |
7586 | { | |
7587 | del = XEXP (i, 0); | |
e2d2ed72 | 7588 | if (BLOCK_FOR_INSN (del) == bb) |
a13d4ebf | 7589 | { |
589005ff | 7590 | /* We know there is only one since we deleted redundant |
a13d4ebf AM |
7591 | ones during the available computation. */ |
7592 | replace_store_insn (reg, del, bb); | |
7593 | break; | |
7594 | } | |
7595 | } | |
7596 | } | |
7597 | ||
7598 | /* Free memory used by store motion. */ | |
7599 | ||
589005ff | 7600 | static void |
1d088dee | 7601 | free_store_memory (void) |
a13d4ebf AM |
7602 | { |
7603 | free_ldst_mems (); | |
589005ff | 7604 | |
a13d4ebf | 7605 | if (ae_gen) |
5a660bff | 7606 | sbitmap_vector_free (ae_gen); |
a13d4ebf | 7607 | if (ae_kill) |
5a660bff | 7608 | sbitmap_vector_free (ae_kill); |
a13d4ebf | 7609 | if (transp) |
5a660bff | 7610 | sbitmap_vector_free (transp); |
a13d4ebf | 7611 | if (st_antloc) |
5a660bff | 7612 | sbitmap_vector_free (st_antloc); |
a13d4ebf | 7613 | if (pre_insert_map) |
5a660bff | 7614 | sbitmap_vector_free (pre_insert_map); |
a13d4ebf | 7615 | if (pre_delete_map) |
5a660bff | 7616 | sbitmap_vector_free (pre_delete_map); |
aaa4ca30 AJ |
7617 | if (reg_set_in_block) |
7618 | sbitmap_vector_free (reg_set_in_block); | |
589005ff | 7619 | |
a13d4ebf AM |
7620 | ae_gen = ae_kill = transp = st_antloc = NULL; |
7621 | pre_insert_map = pre_delete_map = reg_set_in_block = NULL; | |
7622 | } | |
7623 | ||
7624 | /* Perform store motion. Much like gcse, except we move expressions the | |
7625 | other way by looking at the flowgraph in reverse. */ | |
7626 | ||
7627 | static void | |
1d088dee | 7628 | store_motion (void) |
a13d4ebf | 7629 | { |
e0082a72 | 7630 | basic_block bb; |
0b17ab2f | 7631 | int x; |
a13d4ebf | 7632 | struct ls_expr * ptr; |
adfcce61 | 7633 | int update_flow = 0; |
aaa4ca30 | 7634 | |
a13d4ebf AM |
7635 | if (gcse_file) |
7636 | { | |
7637 | fprintf (gcse_file, "before store motion\n"); | |
7638 | print_rtl (gcse_file, get_insns ()); | |
7639 | } | |
7640 | ||
a13d4ebf | 7641 | init_alias_analysis (); |
aaa4ca30 | 7642 | |
47a3dae1 | 7643 | /* Find all the available and anticipatable stores. */ |
a13d4ebf AM |
7644 | num_stores = compute_store_table (); |
7645 | if (num_stores == 0) | |
7646 | { | |
aaa4ca30 | 7647 | sbitmap_vector_free (reg_set_in_block); |
a13d4ebf AM |
7648 | end_alias_analysis (); |
7649 | return; | |
7650 | } | |
7651 | ||
47a3dae1 | 7652 | /* Now compute kill & transp vectors. */ |
a13d4ebf | 7653 | build_store_vectors (); |
47a3dae1 | 7654 | add_noreturn_fake_exit_edges (); |
a13d4ebf | 7655 | |
589005ff KH |
7656 | edge_list = pre_edge_rev_lcm (gcse_file, num_stores, transp, ae_gen, |
7657 | st_antloc, ae_kill, &pre_insert_map, | |
a13d4ebf AM |
7658 | &pre_delete_map); |
7659 | ||
7660 | /* Now we want to insert the new stores which are going to be needed. */ | |
7661 | for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr)) | |
7662 | { | |
e0082a72 ZD |
7663 | FOR_EACH_BB (bb) |
7664 | if (TEST_BIT (pre_delete_map[bb->index], ptr->index)) | |
7665 | delete_store (ptr, bb); | |
a13d4ebf | 7666 | |
0b17ab2f RH |
7667 | for (x = 0; x < NUM_EDGES (edge_list); x++) |
7668 | if (TEST_BIT (pre_insert_map[x], ptr->index)) | |
7669 | update_flow |= insert_store (ptr, INDEX_EDGE (edge_list, x)); | |
a13d4ebf AM |
7670 | } |
7671 | ||
7672 | if (update_flow) | |
7673 | commit_edge_insertions (); | |
aaa4ca30 | 7674 | |
a13d4ebf AM |
7675 | free_store_memory (); |
7676 | free_edge_list (edge_list); | |
7677 | remove_fake_edges (); | |
7678 | end_alias_analysis (); | |
7679 | } | |
e2500fed | 7680 | |
a0134312 RS |
7681 | \f |
7682 | /* Entry point for jump bypassing optimization pass. */ | |
7683 | ||
7684 | int | |
1d088dee | 7685 | bypass_jumps (FILE *file) |
a0134312 RS |
7686 | { |
7687 | int changed; | |
7688 | ||
7689 | /* We do not construct an accurate cfg in functions which call | |
7690 | setjmp, so just punt to be safe. */ | |
7691 | if (current_function_calls_setjmp) | |
7692 | return 0; | |
7693 | ||
7694 | /* For calling dump_foo fns from gdb. */ | |
7695 | debug_stderr = stderr; | |
7696 | gcse_file = file; | |
7697 | ||
7698 | /* Identify the basic block information for this function, including | |
7699 | successors and predecessors. */ | |
7700 | max_gcse_regno = max_reg_num (); | |
7701 | ||
7702 | if (file) | |
7703 | dump_flow_info (file); | |
7704 | ||
7705 | /* Return if there's nothing to do. */ | |
7706 | if (n_basic_blocks <= 1) | |
7707 | return 0; | |
7708 | ||
7709 | /* Trying to perform global optimizations on flow graphs which have | |
7710 | a high connectivity will take a long time and is unlikely to be | |
7711 | particularly useful. | |
7712 | ||
7713 | In normal circumstances a cfg should have about twice as many edges | |
7714 | as blocks. But we do not want to punish small functions which have | |
7715 | a couple switch statements. So we require a relatively large number | |
7716 | of basic blocks and the ratio of edges to blocks to be high. */ | |
7717 | if (n_basic_blocks > 1000 && n_edges / n_basic_blocks >= 20) | |
7718 | { | |
7719 | if (warn_disabled_optimization) | |
7720 | warning ("BYPASS disabled: %d > 1000 basic blocks and %d >= 20 edges/basic block", | |
7721 | n_basic_blocks, n_edges / n_basic_blocks); | |
7722 | return 0; | |
7723 | } | |
7724 | ||
7725 | /* If allocating memory for the cprop bitmap would take up too much | |
7726 | storage it's better just to disable the optimization. */ | |
7727 | if ((n_basic_blocks | |
7728 | * SBITMAP_SET_SIZE (max_gcse_regno) | |
7729 | * sizeof (SBITMAP_ELT_TYPE)) > MAX_GCSE_MEMORY) | |
7730 | { | |
7731 | if (warn_disabled_optimization) | |
7732 | warning ("GCSE disabled: %d basic blocks and %d registers", | |
7733 | n_basic_blocks, max_gcse_regno); | |
7734 | ||
7735 | return 0; | |
7736 | } | |
7737 | ||
a0134312 RS |
7738 | gcc_obstack_init (&gcse_obstack); |
7739 | bytes_used = 0; | |
7740 | ||
7741 | /* We need alias. */ | |
7742 | init_alias_analysis (); | |
7743 | ||
7744 | /* Record where pseudo-registers are set. This data is kept accurate | |
7745 | during each pass. ??? We could also record hard-reg information here | |
7746 | [since it's unchanging], however it is currently done during hash table | |
7747 | computation. | |
7748 | ||
7749 | It may be tempting to compute MEM set information here too, but MEM sets | |
7750 | will be subject to code motion one day and thus we need to compute | |
7751 | information about memory sets when we build the hash tables. */ | |
7752 | ||
7753 | alloc_reg_set_mem (max_gcse_regno); | |
7754 | compute_sets (get_insns ()); | |
7755 | ||
7756 | max_gcse_regno = max_reg_num (); | |
7757 | alloc_gcse_mem (get_insns ()); | |
7758 | changed = one_cprop_pass (1, 1, 1); | |
7759 | free_gcse_mem (); | |
7760 | ||
7761 | if (file) | |
7762 | { | |
7763 | fprintf (file, "BYPASS of %s: %d basic blocks, ", | |
7764 | current_function_name, n_basic_blocks); | |
7765 | fprintf (file, "%d bytes\n\n", bytes_used); | |
7766 | } | |
7767 | ||
7768 | obstack_free (&gcse_obstack, NULL); | |
7769 | free_reg_set_mem (); | |
7770 | ||
7771 | /* We are finished with alias. */ | |
7772 | end_alias_analysis (); | |
7773 | allocate_reg_info (max_reg_num (), FALSE, FALSE); | |
7774 | ||
7775 | return changed; | |
7776 | } | |
7777 | ||
e2500fed | 7778 | #include "gt-gcse.h" |