1/* Generic routines for manipulating SSA_NAME expressions
2 Copyright (C) 2003-2017 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify
7it under the terms of the GNU General Public License as published by
8the Free Software Foundation; either version 3, or (at your option)
9any later version.
10
11GCC is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20#include "config.h"
21#include "system.h"
22#include "coretypes.h"
23#include "backend.h"
24#include "tree.h"
25#include "gimple.h"
26#include "tree-pass.h"
27#include "ssa.h"
28#include "gimple-iterator.h"
29#include "stor-layout.h"
30#include "tree-into-ssa.h"
31#include "tree-ssa.h"
32
33/* Rewriting a function into SSA form can create a huge number of SSA_NAMEs,
34 many of which may be thrown away shortly after their creation if jumps
35 were threaded through PHI nodes.
36
37 While our garbage collection mechanisms will handle this situation, it
38 is extremely wasteful to create nodes and throw them away, especially
39 when the nodes can be reused.
40
41 For PR 8361, we can significantly reduce the number of nodes allocated
42 and thus the total amount of memory allocated by managing SSA_NAMEs a
43 little. This additionally helps reduce the amount of work done by the
44 garbage collector. Similar results have been seen on a wider variety
45 of tests (such as the compiler itself).
46
47 Right now we maintain our free list on a per-function basis. It may
48 or may not make sense to maintain the free list for the duration of
49 a compilation unit.
50
51 External code should rely solely upon HIGHEST_SSA_VERSION and the
52 externally defined functions. External code should not know about
53 the details of the free list management.
54
55 External code should also not assume the version number on nodes is
56 monotonically increasing. We reuse the version number when we
57 reuse an SSA_NAME expression. This helps keep arrays and bitmaps
58 more compact. */
59
60
61/* Version numbers with special meanings. We start allocating new version
62 numbers after the special ones. */
63#define UNUSED_NAME_VERSION 0
64
65unsigned int ssa_name_nodes_reused;
66unsigned int ssa_name_nodes_created;
67
68#define FREE_SSANAMES(fun) (fun)->gimple_df->free_ssanames
69#define FREE_SSANAMES_QUEUE(fun) (fun)->gimple_df->free_ssanames_queue
70
71
72/* Initialize management of SSA_NAMEs to default SIZE. If SIZE is
73 zero use default. */
74
75void
76init_ssanames (struct function *fn, int size)
77{
78 if (size < 50)
79 size = 50;
80
81 vec_alloc (SSANAMES (fn), size);
82
83 /* Version 0 is special, so reserve the first slot in the table. Though
84 currently unused, we may use version 0 in alias analysis as part of
85 the heuristics used to group aliases when the alias sets are too
86 large.
87
88 We use vec::quick_push here because we know that SSA_NAMES has at
89 least 50 elements reserved in it. */
90 SSANAMES (fn)->quick_push (NULL_TREE);
91 FREE_SSANAMES (fn) = NULL;
92 FREE_SSANAMES_QUEUE (fn) = NULL;
93
94 fn->gimple_df->ssa_renaming_needed = 0;
95 fn->gimple_df->rename_vops = 0;
96}
97
98/* Finalize management of SSA_NAMEs. */
99
100void
101fini_ssanames (struct function *fn)
102{
103 vec_free (SSANAMES (fn));
104 vec_free (FREE_SSANAMES (fn));
105 vec_free (FREE_SSANAMES_QUEUE (fn));
106}
107
108/* Dump some simple statistics regarding the re-use of SSA_NAME nodes. */
109
110void
111ssanames_print_statistics (void)
112{
113 fprintf (stderr, "SSA_NAME nodes allocated: %u\n", ssa_name_nodes_created);
114 fprintf (stderr, "SSA_NAME nodes reused: %u\n", ssa_name_nodes_reused);
115}
116
117/* Verify the state of the SSA_NAME lists.
118
119 There must be no duplicates on the free list.
120 Every name on the free list must be marked as on the free list.
121 Any name on the free list must not appear in the IL.
122 No names can be leaked. */
123
124DEBUG_FUNCTION void
125verify_ssaname_freelists (struct function *fun)
126{
127 if (!gimple_in_ssa_p (fun))
128 return;
129
130 auto_bitmap names_in_il;
131
132 /* Walk the entire IL noting every SSA_NAME we see. */
133 basic_block bb;
134 FOR_EACH_BB_FN (bb, fun)
135 {
136 tree t;
137 /* First note the result and arguments of PHI nodes. */
138 for (gphi_iterator gsi = gsi_start_phis (bb);
139 !gsi_end_p (gsi);
140 gsi_next (&gsi))
141 {
142 gphi *phi = gsi.phi ();
143 t = gimple_phi_result (phi);
144 bitmap_set_bit (names_in_il, SSA_NAME_VERSION (t));
145
146 for (unsigned int i = 0; i < gimple_phi_num_args (phi); i++)
147 {
148 t = gimple_phi_arg_def (phi, i);
149 if (TREE_CODE (t) == SSA_NAME)
150 bitmap_set_bit (names_in_il, SSA_NAME_VERSION (t));
151 }
152 }
153
154 /* Then note the operands of each statement. */
155 for (gimple_stmt_iterator gsi = gsi_start_bb (bb);
156 !gsi_end_p (gsi);
157 gsi_next (&gsi))
158 {
159 ssa_op_iter iter;
160 gimple *stmt = gsi_stmt (gsi);
161 FOR_EACH_SSA_TREE_OPERAND (t, stmt, iter, SSA_OP_ALL_OPERANDS)
162 bitmap_set_bit (names_in_il, SSA_NAME_VERSION (t));
163 }
164 }
165
166 /* Now walk the free list noting what we find there and verifying
167 there are no duplicates. */
168 auto_bitmap names_in_freelists;
169 if (FREE_SSANAMES (fun))
170 {
171 for (unsigned int i = 0; i < FREE_SSANAMES (fun)->length (); i++)
172 {
173 tree t = (*FREE_SSANAMES (fun))[i];
174
175 /* Verify that the name is marked as being in the free list. */
176 gcc_assert (SSA_NAME_IN_FREE_LIST (t));
177
178 /* Verify the name has not already appeared in the free list and
179 note it in the list of names found in the free list. */
180 gcc_assert (!bitmap_bit_p (names_in_freelists, SSA_NAME_VERSION (t)));
181 bitmap_set_bit (names_in_freelists, SSA_NAME_VERSION (t));
182 }
183 }
184
185 /* Similarly for the names in the pending free list. */
186 if (FREE_SSANAMES_QUEUE (fun))
187 {
188 for (unsigned int i = 0; i < FREE_SSANAMES_QUEUE (fun)->length (); i++)
189 {
190 tree t = (*FREE_SSANAMES_QUEUE (fun))[i];
191
192 /* Verify that the name is marked as being in the free list. */
193 gcc_assert (SSA_NAME_IN_FREE_LIST (t));
194
195 /* Verify the name has not already appeared in the free list and
196 note it in the list of names found in the free list. */
197 gcc_assert (!bitmap_bit_p (names_in_freelists, SSA_NAME_VERSION (t)));
198 bitmap_set_bit (names_in_freelists, SSA_NAME_VERSION (t));
199 }
200 }
201
202 /* If any name appears in both the IL and the freelists, then
203 something horrible has happened. */
204 bool intersect_p = bitmap_intersect_p (names_in_il, names_in_freelists);
205 gcc_assert (!intersect_p);
206
207 /* Names can be queued up for release if there is an ssa update
208 pending. Pretend we saw them in the IL. */
209 if (names_to_release)
210 bitmap_ior_into (names_in_il, names_to_release);
211
212 /* Function splitting can "lose" SSA_NAMEs in an effort to ensure that
213 debug/non-debug compilations have the same SSA_NAMEs. So for each
214 lost SSA_NAME, see if it's likely one from that wart. These will always
215 be marked as default definitions. So we loosely assume that anything
216 marked as a default definition isn't leaked by pretending they are
217 in the IL. */
218 for (unsigned int i = UNUSED_NAME_VERSION + 1; i < num_ssa_names; i++)
219 if (ssa_name (i) && SSA_NAME_IS_DEFAULT_DEF (ssa_name (i)))
220 bitmap_set_bit (names_in_il, i);
221
222 unsigned int i;
223 bitmap_iterator bi;
224 auto_bitmap all_names;
225 bitmap_set_range (all_names, UNUSED_NAME_VERSION + 1, num_ssa_names - 1);
226 bitmap_ior_into (names_in_il, names_in_freelists);
227
228 /* Any name not mentioned in the IL and not in the feelists
229 has been leaked. */
230 EXECUTE_IF_AND_COMPL_IN_BITMAP(all_names, names_in_il,
231 UNUSED_NAME_VERSION + 1, i, bi)
232 gcc_assert (!ssa_name (i));
233}
234
235/* Move all SSA_NAMEs from FREE_SSA_NAMES_QUEUE to FREE_SSA_NAMES.
236
237 We do not, but should have a mode to verify the state of the SSA_NAMEs
238 lists. In particular at this point every name must be in the IL,
239 on the free list or in the queue. Anything else is an error. */
240
241void
242flush_ssaname_freelist (void)
243{
244 vec_safe_splice (FREE_SSANAMES (cfun), FREE_SSANAMES_QUEUE (cfun));
245 vec_safe_truncate (FREE_SSANAMES_QUEUE (cfun), 0);
246}
247
248/* Return an SSA_NAME node for variable VAR defined in statement STMT
249 in function FN. STMT may be an empty statement for artificial
250 references (e.g., default definitions created when a variable is
251 used without a preceding definition). If VERISON is not zero then
252 allocate the SSA name with that version. */
253
254tree
255make_ssa_name_fn (struct function *fn, tree var, gimple *stmt,
256 unsigned int version)
257{
258 tree t;
259 use_operand_p imm;
260
261 gcc_assert (VAR_P (var)
262 || TREE_CODE (var) == PARM_DECL
263 || TREE_CODE (var) == RESULT_DECL
264 || (TYPE_P (var) && is_gimple_reg_type (var)));
265
266 /* Get the specified SSA name version. */
267 if (version != 0)
268 {
269 t = make_node (SSA_NAME);
270 SSA_NAME_VERSION (t) = version;
271 if (version >= SSANAMES (fn)->length ())
272 vec_safe_grow_cleared (SSANAMES (fn), version + 1);
273 gcc_assert ((*SSANAMES (fn))[version] == NULL);
274 (*SSANAMES (fn))[version] = t;
275 ssa_name_nodes_created++;
276 }
277 /* If our free list has an element, then use it. */
278 else if (!vec_safe_is_empty (FREE_SSANAMES (fn)))
279 {
280 t = FREE_SSANAMES (fn)->pop ();
281 ssa_name_nodes_reused++;
282
283 /* The node was cleared out when we put it on the free list, so
284 there is no need to do so again here. */
285 gcc_assert ((*SSANAMES (fn))[SSA_NAME_VERSION (t)] == NULL);
286 (*SSANAMES (fn))[SSA_NAME_VERSION (t)] = t;
287 }
288 else
289 {
290 t = make_node (SSA_NAME);
291 SSA_NAME_VERSION (t) = SSANAMES (fn)->length ();
292 vec_safe_push (SSANAMES (fn), t);
293 ssa_name_nodes_created++;
294 }
295
296 if (TYPE_P (var))
297 {
298 TREE_TYPE (t) = TYPE_MAIN_VARIANT (var);
299 SET_SSA_NAME_VAR_OR_IDENTIFIER (t, NULL_TREE);
300 }
301 else
302 {
303 TREE_TYPE (t) = TREE_TYPE (var);
304 SET_SSA_NAME_VAR_OR_IDENTIFIER (t, var);
305 }
306 SSA_NAME_DEF_STMT (t) = stmt;
307 if (POINTER_TYPE_P (TREE_TYPE (t)))
308 SSA_NAME_PTR_INFO (t) = NULL;
309 else
310 SSA_NAME_RANGE_INFO (t) = NULL;
311
312 SSA_NAME_IN_FREE_LIST (t) = 0;
313 SSA_NAME_IS_DEFAULT_DEF (t) = 0;
314 imm = &(SSA_NAME_IMM_USE_NODE (t));
315 imm->use = NULL;
316 imm->prev = imm;
317 imm->next = imm;
318 imm->loc.ssa_name = t;
319
320 return t;
321}
322
323/* Helper function for set_range_info.
324
325 Store range information RANGE_TYPE, MIN, and MAX to tree ssa_name
326 NAME. */
327
328void
329set_range_info_raw (tree name, enum value_range_type range_type,
330 const wide_int_ref &min, const wide_int_ref &max)
331{
332 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name)));
333 gcc_assert (range_type == VR_RANGE || range_type == VR_ANTI_RANGE);
334 range_info_def *ri = SSA_NAME_RANGE_INFO (name);
335 unsigned int precision = TYPE_PRECISION (TREE_TYPE (name));
336
337 /* Allocate if not available. */
338 if (ri == NULL)
339 {
340 size_t size = (sizeof (range_info_def)
341 + trailing_wide_ints <3>::extra_size (precision));
342 ri = static_cast<range_info_def *> (ggc_internal_alloc (size));
343 ri->ints.set_precision (precision);
344 SSA_NAME_RANGE_INFO (name) = ri;
345 ri->set_nonzero_bits (wi::shwi (-1, precision));
346 }
347
348 /* Record the range type. */
349 if (SSA_NAME_RANGE_TYPE (name) != range_type)
350 SSA_NAME_ANTI_RANGE_P (name) = (range_type == VR_ANTI_RANGE);
351
352 /* Set the values. */
353 ri->set_min (min);
354 ri->set_max (max);
355
356 /* If it is a range, try to improve nonzero_bits from the min/max. */
357 if (range_type == VR_RANGE)
358 {
359 wide_int xorv = ri->get_min () ^ ri->get_max ();
360 if (xorv != 0)
361 xorv = wi::mask (precision - wi::clz (xorv), false, precision);
362 ri->set_nonzero_bits (ri->get_nonzero_bits () & (ri->get_min () | xorv));
363 }
364}
365
366/* Store range information RANGE_TYPE, MIN, and MAX to tree ssa_name
367 NAME while making sure we don't store useless range info. */
368
369void
370set_range_info (tree name, enum value_range_type range_type,
371 const wide_int_ref &min, const wide_int_ref &max)
372{
373 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name)));
374
375 /* A range of the entire domain is really no range at all. */
376 tree type = TREE_TYPE (name);
377 if (min == wi::min_value (TYPE_PRECISION (type), TYPE_SIGN (type))
378 && max == wi::max_value (TYPE_PRECISION (type), TYPE_SIGN (type)))
379 {
380 range_info_def *ri = SSA_NAME_RANGE_INFO (name);
381 if (ri == NULL)
382 return;
383 if (ri->get_nonzero_bits () == -1)
384 {
385 ggc_free (ri);
386 SSA_NAME_RANGE_INFO (name) = NULL;
387 return;
388 }
389 }
390
391 set_range_info_raw (name, range_type, min, max);
392}
393
394
395/* Gets range information MIN, MAX and returns enum value_range_type
396 corresponding to tree ssa_name NAME. enum value_range_type returned
397 is used to determine if MIN and MAX are valid values. */
398
399enum value_range_type
400get_range_info (const_tree name, wide_int *min, wide_int *max)
401{
402 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name)));
403 gcc_assert (min && max);
404 range_info_def *ri = SSA_NAME_RANGE_INFO (name);
405
406 /* Return VR_VARYING for SSA_NAMEs with NULL RANGE_INFO or SSA_NAMEs
407 with integral types width > 2 * HOST_BITS_PER_WIDE_INT precision. */
408 if (!ri || (GET_MODE_PRECISION (SCALAR_INT_TYPE_MODE (TREE_TYPE (name)))
409 > 2 * HOST_BITS_PER_WIDE_INT))
410 return VR_VARYING;
411
412 *min = ri->get_min ();
413 *max = ri->get_max ();
414 return SSA_NAME_RANGE_TYPE (name);
415}
416
417/* Set nonnull attribute to pointer NAME. */
418
419void
420set_ptr_nonnull (tree name)
421{
422 gcc_assert (POINTER_TYPE_P (TREE_TYPE (name)));
423 struct ptr_info_def *pi = get_ptr_info (name);
424 pi->pt.null = 0;
425}
426
427/* Return nonnull attribute of pointer NAME. */
428bool
429get_ptr_nonnull (const_tree name)
430{
431 gcc_assert (POINTER_TYPE_P (TREE_TYPE (name)));
432 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (name);
433 if (pi == NULL)
434 return false;
435 /* TODO Now pt->null is conservatively set to true in PTA
436 analysis. vrp is the only pass (including ipa-vrp)
437 that clears pt.null via set_ptr_nonull when it knows
438 for sure. PTA will preserves the pt.null value set by VRP.
439
440 When PTA analysis is improved, pt.anything, pt.nonlocal
441 and pt.escaped may also has to be considered before
442 deciding that pointer cannot point to NULL. */
443 return !pi->pt.null;
444}
445
446/* Change non-zero bits bitmask of NAME. */
447
448void
449set_nonzero_bits (tree name, const wide_int_ref &mask)
450{
451 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name)));
452 if (SSA_NAME_RANGE_INFO (name) == NULL)
453 {
454 if (mask == -1)
455 return;
456 set_range_info_raw (name, VR_RANGE,
457 wi::to_wide (TYPE_MIN_VALUE (TREE_TYPE (name))),
458 wi::to_wide (TYPE_MAX_VALUE (TREE_TYPE (name))));
459 }
460 range_info_def *ri = SSA_NAME_RANGE_INFO (name);
461 ri->set_nonzero_bits (mask);
462}
463
464/* Return a widest_int with potentially non-zero bits in SSA_NAME
465 NAME, the constant for INTEGER_CST, or -1 if unknown. */
466
467wide_int
468get_nonzero_bits (const_tree name)
469{
470 if (TREE_CODE (name) == INTEGER_CST)
471 return wi::to_wide (name);
472
473 /* Use element_precision instead of TYPE_PRECISION so complex and
474 vector types get a non-zero precision. */
475 unsigned int precision = element_precision (TREE_TYPE (name));
476 if (POINTER_TYPE_P (TREE_TYPE (name)))
477 {
478 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (name);
479 if (pi && pi->align)
480 return wi::shwi (-(HOST_WIDE_INT) pi->align
481 | (HOST_WIDE_INT) pi->misalign, precision);
482 return wi::shwi (-1, precision);
483 }
484
485 range_info_def *ri = SSA_NAME_RANGE_INFO (name);
486 if (!ri)
487 return wi::shwi (-1, precision);
488
489 return ri->get_nonzero_bits ();
490}
491
492/* Return TRUE is OP, an SSA_NAME has a range of values [0..1], false
493 otherwise.
494
495 This can be because it is a boolean type, any unsigned integral
496 type with a single bit of precision, or has known range of [0..1]
497 via VRP analysis. */
498
499bool
500ssa_name_has_boolean_range (tree op)
501{
502 gcc_assert (TREE_CODE (op) == SSA_NAME);
503
504 /* Boolean types always have a range [0..1]. */
505 if (TREE_CODE (TREE_TYPE (op)) == BOOLEAN_TYPE)
506 return true;
507
508 /* An integral type with a single bit of precision. */
509 if (INTEGRAL_TYPE_P (TREE_TYPE (op))
510 && TYPE_UNSIGNED (TREE_TYPE (op))
511 && TYPE_PRECISION (TREE_TYPE (op)) == 1)
512 return true;
513
514 /* An integral type with more precision, but the object
515 only takes on values [0..1] as determined by VRP
516 analysis. */
517 if (INTEGRAL_TYPE_P (TREE_TYPE (op))
518 && (TYPE_PRECISION (TREE_TYPE (op)) > 1)
519 && wi::eq_p (get_nonzero_bits (op), 1))
520 return true;
521
522 return false;
523}
524
525/* We no longer need the SSA_NAME expression VAR, release it so that
526 it may be reused.
527
528 Note it is assumed that no calls to make_ssa_name will be made
529 until all uses of the ssa name are released and that the only
530 use of the SSA_NAME expression is to check its SSA_NAME_VAR. All
531 other fields must be assumed clobbered. */
532
533void
534release_ssa_name_fn (struct function *fn, tree var)
535{
536 if (!var)
537 return;
538
539 /* Never release the default definition for a symbol. It's a
540 special SSA name that should always exist once it's created. */
541 if (SSA_NAME_IS_DEFAULT_DEF (var))
542 return;
543
544 /* If VAR has been registered for SSA updating, don't remove it.
545 After update_ssa has run, the name will be released. */
546 if (name_registered_for_update_p (var))
547 {
548 release_ssa_name_after_update_ssa (var);
549 return;
550 }
551
552 /* release_ssa_name can be called multiple times on a single SSA_NAME.
553 However, it should only end up on our free list one time. We
554 keep a status bit in the SSA_NAME node itself to indicate it has
555 been put on the free list.
556
557 Note that once on the freelist you can not reference the SSA_NAME's
558 defining statement. */
559 if (! SSA_NAME_IN_FREE_LIST (var))
560 {
561 tree saved_ssa_name_var = SSA_NAME_VAR (var);
562 int saved_ssa_name_version = SSA_NAME_VERSION (var);
563 use_operand_p imm = &(SSA_NAME_IMM_USE_NODE (var));
564
565 if (MAY_HAVE_DEBUG_BIND_STMTS)
566 insert_debug_temp_for_var_def (NULL, var);
567
568 if (flag_checking)
569 verify_imm_links (stderr, var);
570 while (imm->next != imm)
571 delink_imm_use (imm->next);
572
573 (*SSANAMES (fn))[SSA_NAME_VERSION (var)] = NULL_TREE;
574 memset (var, 0, tree_size (var));
575
576 imm->prev = imm;
577 imm->next = imm;
578 imm->loc.ssa_name = var;
579
580 /* First put back the right tree node so that the tree checking
581 macros do not complain. */
582 TREE_SET_CODE (var, SSA_NAME);
583
584 /* Restore the version number. */
585 SSA_NAME_VERSION (var) = saved_ssa_name_version;
586
587 /* Hopefully this can go away once we have the new incremental
588 SSA updating code installed. */
589 SET_SSA_NAME_VAR_OR_IDENTIFIER (var, saved_ssa_name_var);
590
591 /* Note this SSA_NAME is now in the first list. */
592 SSA_NAME_IN_FREE_LIST (var) = 1;
593
594 /* And finally queue it so that it will be put on the free list. */
595 vec_safe_push (FREE_SSANAMES_QUEUE (fn), var);
596 }
597}
598
599/* If the alignment of the pointer described by PI is known, return true and
600 store the alignment and the deviation from it into *ALIGNP and *MISALIGNP
601 respectively. Otherwise return false. */
602
603bool
604get_ptr_info_alignment (struct ptr_info_def *pi, unsigned int *alignp,
605 unsigned int *misalignp)
606{
607 if (pi->align)
608 {
609 *alignp = pi->align;
610 *misalignp = pi->misalign;
611 return true;
612 }
613 else
614 return false;
615}
616
617/* State that the pointer described by PI has unknown alignment. */
618
619void
620mark_ptr_info_alignment_unknown (struct ptr_info_def *pi)
621{
622 pi->align = 0;
623 pi->misalign = 0;
624}
625
626/* Store the power-of-two byte alignment and the deviation from that
627 alignment of pointer described by PI to ALIOGN and MISALIGN
628 respectively. */
629
630void
631set_ptr_info_alignment (struct ptr_info_def *pi, unsigned int align,
632 unsigned int misalign)
633{
634 gcc_checking_assert (align != 0);
635 gcc_assert ((align & (align - 1)) == 0);
636 gcc_assert ((misalign & ~(align - 1)) == 0);
637
638 pi->align = align;
639 pi->misalign = misalign;
640}
641
642/* If pointer described by PI has known alignment, increase its known
643 misalignment by INCREMENT modulo its current alignment. */
644
645void
646adjust_ptr_info_misalignment (struct ptr_info_def *pi,
647 unsigned int increment)
648{
649 if (pi->align != 0)
650 {
651 pi->misalign += increment;
652 pi->misalign &= (pi->align - 1);
653 }
654}
655
656/* Return the alias information associated with pointer T. It creates a
657 new instance if none existed. */
658
659struct ptr_info_def *
660get_ptr_info (tree t)
661{
662 struct ptr_info_def *pi;
663
664 gcc_assert (POINTER_TYPE_P (TREE_TYPE (t)));
665
666 pi = SSA_NAME_PTR_INFO (t);
667 if (pi == NULL)
668 {
669 pi = ggc_cleared_alloc<ptr_info_def> ();
670 pt_solution_reset (&pi->pt);
671 mark_ptr_info_alignment_unknown (pi);
672 SSA_NAME_PTR_INFO (t) = pi;
673 }
674
675 return pi;
676}
677
678
679/* Creates a new SSA name using the template NAME tobe defined by
680 statement STMT in function FN. */
681
682tree
683copy_ssa_name_fn (struct function *fn, tree name, gimple *stmt)
684{
685 tree new_name;
686
687 if (SSA_NAME_VAR (name))
688 new_name = make_ssa_name_fn (fn, SSA_NAME_VAR (name), stmt);
689 else
690 {
691 new_name = make_ssa_name_fn (fn, TREE_TYPE (name), stmt);
692 SET_SSA_NAME_VAR_OR_IDENTIFIER (new_name, SSA_NAME_IDENTIFIER (name));
693 }
694
695 return new_name;
696}
697
698
699/* Creates a duplicate of the ptr_info_def at PTR_INFO for use by
700 the SSA name NAME. */
701
702void
703duplicate_ssa_name_ptr_info (tree name, struct ptr_info_def *ptr_info)
704{
705 struct ptr_info_def *new_ptr_info;
706
707 gcc_assert (POINTER_TYPE_P (TREE_TYPE (name)));
708 gcc_assert (!SSA_NAME_PTR_INFO (name));
709
710 if (!ptr_info)
711 return;
712
713 new_ptr_info = ggc_alloc<ptr_info_def> ();
714 *new_ptr_info = *ptr_info;
715
716 SSA_NAME_PTR_INFO (name) = new_ptr_info;
717}
718
719/* Creates a duplicate of the range_info_def at RANGE_INFO of type
720 RANGE_TYPE for use by the SSA name NAME. */
721void
722duplicate_ssa_name_range_info (tree name, enum value_range_type range_type,
723 struct range_info_def *range_info)
724{
725 struct range_info_def *new_range_info;
726
727 gcc_assert (!POINTER_TYPE_P (TREE_TYPE (name)));
728 gcc_assert (!SSA_NAME_RANGE_INFO (name));
729
730 if (!range_info)
731 return;
732
733 unsigned int precision = TYPE_PRECISION (TREE_TYPE (name));
734 size_t size = (sizeof (range_info_def)
735 + trailing_wide_ints <3>::extra_size (precision));
736 new_range_info = static_cast<range_info_def *> (ggc_internal_alloc (size));
737 memcpy (new_range_info, range_info, size);
738
739 gcc_assert (range_type == VR_RANGE || range_type == VR_ANTI_RANGE);
740 SSA_NAME_ANTI_RANGE_P (name) = (range_type == VR_ANTI_RANGE);
741 SSA_NAME_RANGE_INFO (name) = new_range_info;
742}
743
744
745
746/* Creates a duplicate of a ssa name NAME tobe defined by statement STMT
747 in function FN. */
748
749tree
750duplicate_ssa_name_fn (struct function *fn, tree name, gimple *stmt)
751{
752 tree new_name = copy_ssa_name_fn (fn, name, stmt);
753 if (POINTER_TYPE_P (TREE_TYPE (name)))
754 {
755 struct ptr_info_def *old_ptr_info = SSA_NAME_PTR_INFO (name);
756
757 if (old_ptr_info)
758 duplicate_ssa_name_ptr_info (new_name, old_ptr_info);
759 }
760 else
761 {
762 struct range_info_def *old_range_info = SSA_NAME_RANGE_INFO (name);
763
764 if (old_range_info)
765 duplicate_ssa_name_range_info (new_name, SSA_NAME_RANGE_TYPE (name),
766 old_range_info);
767 }
768
769 return new_name;
770}
771
772
773/* Reset all flow sensitive data on NAME such as range-info, nonzero
774 bits and alignment. */
775
776void
777reset_flow_sensitive_info (tree name)
778{
779 if (POINTER_TYPE_P (TREE_TYPE (name)))
780 {
781 /* points-to info is not flow-sensitive. */
782 if (SSA_NAME_PTR_INFO (name))
783 mark_ptr_info_alignment_unknown (SSA_NAME_PTR_INFO (name));
784 }
785 else
786 SSA_NAME_RANGE_INFO (name) = NULL;
787}
788
789/* Clear all flow sensitive data from all statements and PHI definitions
790 in BB. */
791
792void
793reset_flow_sensitive_info_in_bb (basic_block bb)
794{
795 for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);
796 gsi_next (&gsi))
797 {
798 gimple *stmt = gsi_stmt (gsi);
799 ssa_op_iter i;
800 tree op;
801 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_DEF)
802 reset_flow_sensitive_info (op);
803 }
804
805 for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
806 gsi_next (&gsi))
807 {
808 tree phi_def = gimple_phi_result (gsi.phi ());
809 reset_flow_sensitive_info (phi_def);
810 }
811}
812
813/* Release all the SSA_NAMEs created by STMT. */
814
815void
816release_defs (gimple *stmt)
817{
818 tree def;
819 ssa_op_iter iter;
820
821 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
822 if (TREE_CODE (def) == SSA_NAME)
823 release_ssa_name (def);
824}
825
826
827/* Replace the symbol associated with SSA_NAME with SYM. */
828
829void
830replace_ssa_name_symbol (tree ssa_name, tree sym)
831{
832 SET_SSA_NAME_VAR_OR_IDENTIFIER (ssa_name, sym);
833 TREE_TYPE (ssa_name) = TREE_TYPE (sym);
834}
835
836/* Release the vector of free SSA_NAMEs and compact the vector of SSA_NAMEs
837 that are live. */
838
839static void
840release_free_names_and_compact_live_names (function *fun)
841{
842 unsigned i, j;
843 int n = vec_safe_length (FREE_SSANAMES (fun));
844
845 /* Now release the freelist. */
846 vec_free (FREE_SSANAMES (fun));
847
848 /* And compact the SSA number space. We make sure to not change the
849 relative order of SSA versions. */
850 for (i = 1, j = 1; i < fun->gimple_df->ssa_names->length (); ++i)
851 {
852 tree name = ssa_name (i);
853 if (name)
854 {
855 if (i != j)
856 {
857 SSA_NAME_VERSION (name) = j;
858 (*fun->gimple_df->ssa_names)[j] = name;
859 }
860 j++;
861 }
862 }
863 fun->gimple_df->ssa_names->truncate (j);
864
865 statistics_counter_event (fun, "SSA names released", n);
866 statistics_counter_event (fun, "SSA name holes removed", i - j);
867 if (dump_file)
868 fprintf (dump_file, "Released %i names, %.2f%%, removed %i holes\n",
869 n, n * 100.0 / num_ssa_names, i - j);
870}
871
872/* Return SSA names that are unused to GGC memory and compact the SSA
873 version namespace. This is used to keep footprint of compiler during
874 interprocedural optimization. */
875
876namespace {
877
878const pass_data pass_data_release_ssa_names =
879{
880 GIMPLE_PASS, /* type */
881 "release_ssa", /* name */
882 OPTGROUP_NONE, /* optinfo_flags */
883 TV_TREE_SSA_OTHER, /* tv_id */
884 PROP_ssa, /* properties_required */
885 0, /* properties_provided */
886 0, /* properties_destroyed */
887 TODO_remove_unused_locals, /* todo_flags_start */
888 0, /* todo_flags_finish */
889};
890
891class pass_release_ssa_names : public gimple_opt_pass
892{
893public:
894 pass_release_ssa_names (gcc::context *ctxt)
895 : gimple_opt_pass (pass_data_release_ssa_names, ctxt)
896 {}
897
898 /* opt_pass methods: */
899 virtual unsigned int execute (function *);
900
901}; // class pass_release_ssa_names
902
903unsigned int
904pass_release_ssa_names::execute (function *fun)
905{
906 release_free_names_and_compact_live_names (fun);
907 return 0;
908}
909
910} // anon namespace
911
912gimple_opt_pass *
913make_pass_release_ssa_names (gcc::context *ctxt)
914{
915 return new pass_release_ssa_names (ctxt);
916}
917