1 /* Scalar Replacement of Aggregates (SRA) converts some structure
2 references into scalar references, exposing them to the scalar
4 Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
5 Contributed by Martin Jambor <mjambor@suse.cz>
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License as published by the Free
11 Software Foundation; either version 3, or (at your option) any later
14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
23 /* This file implements Scalar Reduction of Aggregates (SRA). SRA is run
24 twice, once in the early stages of compilation (early SRA) and once in the
25 late stages (late SRA). The aim of both is to turn references to scalar
26 parts of aggregates into uses of independent scalar variables.
28 The two passes are nearly identical, the only difference is that early SRA
29 does not scalarize unions which are used as the result in a GIMPLE_RETURN
30 statement because together with inlining this can lead to weird type
33 Both passes operate in four stages:
35 1. The declarations that have properties which make them candidates for
36 scalarization are identified in function find_var_candidates(). The
37 candidates are stored in candidate_bitmap.
39 2. The function body is scanned. In the process, declarations which are
40 used in a manner that prevent their scalarization are removed from the
41 candidate bitmap. More importantly, for every access into an aggregate,
42 an access structure (struct access) is created by create_access() and
43 stored in a vector associated with the aggregate. Among other
44 information, the aggregate declaration, the offset and size of the access
45 and its type are stored in the structure.
47 On a related note, assign_link structures are created for every assign
48 statement between candidate aggregates and attached to the related
51 3. The vectors of accesses are analyzed. They are first sorted according to
52 their offset and size and then scanned for partially overlapping accesses
53 (i.e. those which overlap but one is not entirely within another). Such
54 an access disqualifies the whole aggregate from being scalarized.
56 If there is no such inhibiting overlap, a representative access structure
57 is chosen for every unique combination of offset and size. Afterwards,
58 the pass builds a set of trees from these structures, in which children
59 of an access are within their parent (in terms of offset and size).
61 Then accesses are propagated whenever possible (i.e. in cases when it
62 does not create a partially overlapping access) across assign_links from
63 the right hand side to the left hand side.
65 Then the set of trees for each declaration is traversed again and those
66 accesses which should be replaced by a scalar are identified.
68 4. The function is traversed again, and for every reference into an
69 aggregate that has some component which is about to be scalarized,
70 statements are amended and new statements are created as necessary.
71 Finally, if a parameter got scalarized, the scalar replacements are
72 initialized with values from respective parameter aggregates. */
76 #include "coretypes.h"
77 #include "alloc-pool.h"
82 #include "tree-flow.h"
84 #include "tree-pretty-print.h"
85 #include "statistics.h"
86 #include "tree-dump.h"
92 #include "tree-inline.h"
93 #include "gimple-pretty-print.h"
95 /* Enumeration of all aggregate reductions we can do. */
96 enum sra_mode { SRA_MODE_EARLY_IPA, /* early call regularization */
97 SRA_MODE_EARLY_INTRA, /* early intraprocedural SRA */
98 SRA_MODE_INTRA }; /* late intraprocedural SRA */
100 /* Global variable describing which aggregate reduction we are performing at
102 static enum sra_mode sra_mode;
106 /* ACCESS represents each access to an aggregate variable (as a whole or a
107 part). It can also represent a group of accesses that refer to exactly the
108 same fragment of an aggregate (i.e. those that have exactly the same offset
109 and size). Such representatives for a single aggregate, once determined,
110 are linked in a linked list and have the group fields set.
112 Moreover, when doing intraprocedural SRA, a tree is built from those
113 representatives (by the means of first_child and next_sibling pointers), in
114 which all items in a subtree are "within" the root, i.e. their offset is
115 greater or equal to offset of the root and offset+size is smaller or equal
116 to offset+size of the root. Children of an access are sorted by offset.
118 Note that accesses to parts of vector and complex number types always
119 represented by an access to the whole complex number or a vector. It is a
120 duty of the modifying functions to replace them appropriately. */
124 /* Values returned by `get_ref_base_and_extent' for each component reference
125 If EXPR isn't a component reference just set `BASE = EXPR', `OFFSET = 0',
126 `SIZE = TREE_SIZE (TREE_TYPE (expr))'. */
127 HOST_WIDE_INT offset;
131 /* Expression. It is context dependent so do not use it to create new
132 expressions to access the original aggregate. See PR 42154 for a
138 /* The statement this access belongs to. */
141 /* Next group representative for this aggregate. */
142 struct access *next_grp;
144 /* Pointer to the group representative. Pointer to itself if the struct is
145 the representative. */
146 struct access *group_representative;
148 /* If this access has any children (in terms of the definition above), this
149 points to the first one. */
150 struct access *first_child;
152 /* In intraprocedural SRA, pointer to the next sibling in the access tree as
153 described above. In IPA-SRA this is a pointer to the next access
154 belonging to the same group (having the same representative). */
155 struct access *next_sibling;
157 /* Pointers to the first and last element in the linked list of assign
159 struct assign_link *first_link, *last_link;
161 /* Pointer to the next access in the work queue. */
162 struct access *next_queued;
164 /* Replacement variable for this access "region." Never to be accessed
165 directly, always only by the means of get_access_replacement() and only
166 when grp_to_be_replaced flag is set. */
167 tree replacement_decl;
169 /* Is this particular access write access? */
172 /* Is this access an artificial one created to scalarize some record
174 unsigned total_scalarization : 1;
176 /* Is this access an access to a non-addressable field? */
177 unsigned non_addressable : 1;
179 /* Is this access currently in the work queue? */
180 unsigned grp_queued : 1;
182 /* Does this group contain a write access? This flag is propagated down the
184 unsigned grp_write : 1;
186 /* Does this group contain a read access? This flag is propagated down the
188 unsigned grp_read : 1;
190 /* Does this group contain a read access that comes from an assignment
191 statement? This flag is propagated down the access tree. */
192 unsigned grp_assignment_read : 1;
194 /* Does this group contain a write access that comes from an assignment
195 statement? This flag is propagated down the access tree. */
196 unsigned grp_assignment_write : 1;
198 /* Does this group contain a read access through a scalar type? This flag is
199 not propagated in the access tree in any direction. */
200 unsigned grp_scalar_read : 1;
202 /* Does this group contain a write access through a scalar type? This flag
203 is not propagated in the access tree in any direction. */
204 unsigned grp_scalar_write : 1;
206 /* Other passes of the analysis use this bit to make function
207 analyze_access_subtree create scalar replacements for this group if
209 unsigned grp_hint : 1;
211 /* Is the subtree rooted in this access fully covered by scalar
213 unsigned grp_covered : 1;
215 /* If set to true, this access and all below it in an access tree must not be
217 unsigned grp_unscalarizable_region : 1;
219 /* Whether data have been written to parts of the aggregate covered by this
220 access which is not to be scalarized. This flag is propagated up in the
222 unsigned grp_unscalarized_data : 1;
224 /* Does this access and/or group contain a write access through a
226 unsigned grp_partial_lhs : 1;
228 /* Set when a scalar replacement should be created for this variable. We do
229 the decision and creation at different places because create_tmp_var
230 cannot be called from within FOR_EACH_REFERENCED_VAR. */
231 unsigned grp_to_be_replaced : 1;
233 /* Should TREE_NO_WARNING of a replacement be set? */
234 unsigned grp_no_warning : 1;
236 /* Is it possible that the group refers to data which might be (directly or
237 otherwise) modified? */
238 unsigned grp_maybe_modified : 1;
240 /* Set when this is a representative of a pointer to scalar (i.e. by
241 reference) parameter which we consider for turning into a plain scalar
242 (i.e. a by value parameter). */
243 unsigned grp_scalar_ptr : 1;
245 /* Set when we discover that this pointer is not safe to dereference in the
247 unsigned grp_not_necessarilly_dereferenced : 1;
250 typedef struct access *access_p;
252 DEF_VEC_P (access_p);
253 DEF_VEC_ALLOC_P (access_p, heap);
255 /* Alloc pool for allocating access structures. */
256 static alloc_pool access_pool;
258 /* A structure linking lhs and rhs accesses from an aggregate assignment. They
259 are used to propagate subaccesses from rhs to lhs as long as they don't
260 conflict with what is already there. */
263 struct access *lacc, *racc;
264 struct assign_link *next;
267 /* Alloc pool for allocating assign link structures. */
268 static alloc_pool link_pool;
270 /* Base (tree) -> Vector (VEC(access_p,heap) *) map. */
271 static struct pointer_map_t *base_access_vec;
273 /* Bitmap of candidates. */
274 static bitmap candidate_bitmap;
276 /* Bitmap of candidates which we should try to entirely scalarize away and
277 those which cannot be (because they are and need be used as a whole). */
278 static bitmap should_scalarize_away_bitmap, cannot_scalarize_away_bitmap;
280 /* Obstack for creation of fancy names. */
281 static struct obstack name_obstack;
283 /* Head of a linked list of accesses that need to have its subaccesses
284 propagated to their assignment counterparts. */
285 static struct access *work_queue_head;
287 /* Number of parameters of the analyzed function when doing early ipa SRA. */
288 static int func_param_count;
290 /* scan_function sets the following to true if it encounters a call to
291 __builtin_apply_args. */
292 static bool encountered_apply_args;
294 /* Set by scan_function when it finds a recursive call. */
295 static bool encountered_recursive_call;
297 /* Set by scan_function when it finds a recursive call with less actual
298 arguments than formal parameters.. */
299 static bool encountered_unchangable_recursive_call;
301 /* This is a table in which for each basic block and parameter there is a
302 distance (offset + size) in that parameter which is dereferenced and
303 accessed in that BB. */
304 static HOST_WIDE_INT *bb_dereferences;
305 /* Bitmap of BBs that can cause the function to "stop" progressing by
306 returning, throwing externally, looping infinitely or calling a function
307 which might abort etc.. */
308 static bitmap final_bbs;
310 /* Representative of no accesses at all. */
311 static struct access no_accesses_representant;
313 /* Predicate to test the special value. */
316 no_accesses_p (struct access *access)
318 return access == &no_accesses_representant;
321 /* Dump contents of ACCESS to file F in a human friendly way. If GRP is true,
322 representative fields are dumped, otherwise those which only describe the
323 individual access are. */
327 /* Number of processed aggregates is readily available in
328 analyze_all_variable_accesses and so is not stored here. */
330 /* Number of created scalar replacements. */
333 /* Number of times sra_modify_expr or sra_modify_assign themselves changed an
337 /* Number of statements created by generate_subtree_copies. */
340 /* Number of statements created by load_assign_lhs_subreplacements. */
343 /* Number of times sra_modify_assign has deleted a statement. */
346 /* Number of times sra_modify_assign has to deal with subaccesses of LHS and
347 RHS reparately due to type conversions or nonexistent matching
349 int separate_lhs_rhs_handling;
351 /* Number of parameters that were removed because they were unused. */
352 int deleted_unused_parameters;
354 /* Number of scalars passed as parameters by reference that have been
355 converted to be passed by value. */
356 int scalar_by_ref_to_by_val;
358 /* Number of aggregate parameters that were replaced by one or more of their
360 int aggregate_params_reduced;
362 /* Numbber of components created when splitting aggregate parameters. */
363 int param_reductions_created;
367 dump_access (FILE *f, struct access *access, bool grp)
369 fprintf (f, "access { ");
370 fprintf (f, "base = (%d)'", DECL_UID (access->base));
371 print_generic_expr (f, access->base, 0);
372 fprintf (f, "', offset = " HOST_WIDE_INT_PRINT_DEC, access->offset);
373 fprintf (f, ", size = " HOST_WIDE_INT_PRINT_DEC, access->size);
374 fprintf (f, ", expr = ");
375 print_generic_expr (f, access->expr, 0);
376 fprintf (f, ", type = ");
377 print_generic_expr (f, access->type, 0);
379 fprintf (f, ", total_scalarization = %d, grp_read = %d, grp_write = %d, "
380 "grp_assignment_read = %d, grp_assignment_write = %d, "
381 "grp_scalar_read = %d, grp_scalar_write = %d, "
382 "grp_hint = %d, grp_covered = %d, "
383 "grp_unscalarizable_region = %d, grp_unscalarized_data = %d, "
384 "grp_partial_lhs = %d, grp_to_be_replaced = %d, "
385 "grp_maybe_modified = %d, "
386 "grp_not_necessarilly_dereferenced = %d\n",
387 access->total_scalarization, access->grp_read, access->grp_write,
388 access->grp_assignment_read, access->grp_assignment_write,
389 access->grp_scalar_read, access->grp_scalar_write,
390 access->grp_hint, access->grp_covered,
391 access->grp_unscalarizable_region, access->grp_unscalarized_data,
392 access->grp_partial_lhs, access->grp_to_be_replaced,
393 access->grp_maybe_modified,
394 access->grp_not_necessarilly_dereferenced);
396 fprintf (f, ", write = %d, total_scalarization = %d, "
397 "grp_partial_lhs = %d\n",
398 access->write, access->total_scalarization,
399 access->grp_partial_lhs);
402 /* Dump a subtree rooted in ACCESS to file F, indent by LEVEL. */
405 dump_access_tree_1 (FILE *f, struct access *access, int level)
411 for (i = 0; i < level; i++)
412 fputs ("* ", dump_file);
414 dump_access (f, access, true);
416 if (access->first_child)
417 dump_access_tree_1 (f, access->first_child, level + 1);
419 access = access->next_sibling;
424 /* Dump all access trees for a variable, given the pointer to the first root in
428 dump_access_tree (FILE *f, struct access *access)
430 for (; access; access = access->next_grp)
431 dump_access_tree_1 (f, access, 0);
434 /* Return true iff ACC is non-NULL and has subaccesses. */
437 access_has_children_p (struct access *acc)
439 return acc && acc->first_child;
442 /* Return a vector of pointers to accesses for the variable given in BASE or
443 NULL if there is none. */
445 static VEC (access_p, heap) *
446 get_base_access_vector (tree base)
450 slot = pointer_map_contains (base_access_vec, base);
454 return *(VEC (access_p, heap) **) slot;
457 /* Find an access with required OFFSET and SIZE in a subtree of accesses rooted
458 in ACCESS. Return NULL if it cannot be found. */
460 static struct access *
461 find_access_in_subtree (struct access *access, HOST_WIDE_INT offset,
464 while (access && (access->offset != offset || access->size != size))
466 struct access *child = access->first_child;
468 while (child && (child->offset + child->size <= offset))
469 child = child->next_sibling;
476 /* Return the first group representative for DECL or NULL if none exists. */
478 static struct access *
479 get_first_repr_for_decl (tree base)
481 VEC (access_p, heap) *access_vec;
483 access_vec = get_base_access_vector (base);
487 return VEC_index (access_p, access_vec, 0);
490 /* Find an access representative for the variable BASE and given OFFSET and
491 SIZE. Requires that access trees have already been built. Return NULL if
492 it cannot be found. */
494 static struct access *
495 get_var_base_offset_size_access (tree base, HOST_WIDE_INT offset,
498 struct access *access;
500 access = get_first_repr_for_decl (base);
501 while (access && (access->offset + access->size <= offset))
502 access = access->next_grp;
506 return find_access_in_subtree (access, offset, size);
509 /* Add LINK to the linked list of assign links of RACC. */
511 add_link_to_rhs (struct access *racc, struct assign_link *link)
513 gcc_assert (link->racc == racc);
515 if (!racc->first_link)
517 gcc_assert (!racc->last_link);
518 racc->first_link = link;
521 racc->last_link->next = link;
523 racc->last_link = link;
527 /* Move all link structures in their linked list in OLD_RACC to the linked list
530 relink_to_new_repr (struct access *new_racc, struct access *old_racc)
532 if (!old_racc->first_link)
534 gcc_assert (!old_racc->last_link);
538 if (new_racc->first_link)
540 gcc_assert (!new_racc->last_link->next);
541 gcc_assert (!old_racc->last_link || !old_racc->last_link->next);
543 new_racc->last_link->next = old_racc->first_link;
544 new_racc->last_link = old_racc->last_link;
548 gcc_assert (!new_racc->last_link);
550 new_racc->first_link = old_racc->first_link;
551 new_racc->last_link = old_racc->last_link;
553 old_racc->first_link = old_racc->last_link = NULL;
556 /* Add ACCESS to the work queue (which is actually a stack). */
559 add_access_to_work_queue (struct access *access)
561 if (!access->grp_queued)
563 gcc_assert (!access->next_queued);
564 access->next_queued = work_queue_head;
565 access->grp_queued = 1;
566 work_queue_head = access;
570 /* Pop an access from the work queue, and return it, assuming there is one. */
572 static struct access *
573 pop_access_from_work_queue (void)
575 struct access *access = work_queue_head;
577 work_queue_head = access->next_queued;
578 access->next_queued = NULL;
579 access->grp_queued = 0;
584 /* Allocate necessary structures. */
587 sra_initialize (void)
589 candidate_bitmap = BITMAP_ALLOC (NULL);
590 should_scalarize_away_bitmap = BITMAP_ALLOC (NULL);
591 cannot_scalarize_away_bitmap = BITMAP_ALLOC (NULL);
592 gcc_obstack_init (&name_obstack);
593 access_pool = create_alloc_pool ("SRA accesses", sizeof (struct access), 16);
594 link_pool = create_alloc_pool ("SRA links", sizeof (struct assign_link), 16);
595 base_access_vec = pointer_map_create ();
596 memset (&sra_stats, 0, sizeof (sra_stats));
597 encountered_apply_args = false;
598 encountered_recursive_call = false;
599 encountered_unchangable_recursive_call = false;
602 /* Hook fed to pointer_map_traverse, deallocate stored vectors. */
605 delete_base_accesses (const void *key ATTRIBUTE_UNUSED, void **value,
606 void *data ATTRIBUTE_UNUSED)
608 VEC (access_p, heap) *access_vec;
609 access_vec = (VEC (access_p, heap) *) *value;
610 VEC_free (access_p, heap, access_vec);
615 /* Deallocate all general structures. */
618 sra_deinitialize (void)
620 BITMAP_FREE (candidate_bitmap);
621 BITMAP_FREE (should_scalarize_away_bitmap);
622 BITMAP_FREE (cannot_scalarize_away_bitmap);
623 free_alloc_pool (access_pool);
624 free_alloc_pool (link_pool);
625 obstack_free (&name_obstack, NULL);
627 pointer_map_traverse (base_access_vec, delete_base_accesses, NULL);
628 pointer_map_destroy (base_access_vec);
631 /* Remove DECL from candidates for SRA and write REASON to the dump file if
634 disqualify_candidate (tree decl, const char *reason)
636 bitmap_clear_bit (candidate_bitmap, DECL_UID (decl));
638 if (dump_file && (dump_flags & TDF_DETAILS))
640 fprintf (dump_file, "! Disqualifying ");
641 print_generic_expr (dump_file, decl, 0);
642 fprintf (dump_file, " - %s\n", reason);
646 /* Return true iff the type contains a field or an element which does not allow
650 type_internals_preclude_sra_p (tree type)
655 switch (TREE_CODE (type))
659 case QUAL_UNION_TYPE:
660 for (fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld))
661 if (TREE_CODE (fld) == FIELD_DECL)
663 tree ft = TREE_TYPE (fld);
665 if (TREE_THIS_VOLATILE (fld)
666 || !DECL_FIELD_OFFSET (fld) || !DECL_SIZE (fld)
667 || !host_integerp (DECL_FIELD_OFFSET (fld), 1)
668 || !host_integerp (DECL_SIZE (fld), 1)
669 || !host_integerp (bit_position (fld), 0)
670 || (AGGREGATE_TYPE_P (ft)
671 && int_bit_position (fld) % BITS_PER_UNIT != 0))
674 if (AGGREGATE_TYPE_P (ft)
675 && type_internals_preclude_sra_p (ft))
682 et = TREE_TYPE (type);
684 if (AGGREGATE_TYPE_P (et))
685 return type_internals_preclude_sra_p (et);
694 /* If T is an SSA_NAME, return NULL if it is not a default def or return its
695 base variable if it is. Return T if it is not an SSA_NAME. */
698 get_ssa_base_param (tree t)
700 if (TREE_CODE (t) == SSA_NAME)
702 if (SSA_NAME_IS_DEFAULT_DEF (t))
703 return SSA_NAME_VAR (t);
710 /* Mark a dereference of BASE of distance DIST in a basic block tht STMT
711 belongs to, unless the BB has already been marked as a potentially
715 mark_parm_dereference (tree base, HOST_WIDE_INT dist, gimple stmt)
717 basic_block bb = gimple_bb (stmt);
718 int idx, parm_index = 0;
721 if (bitmap_bit_p (final_bbs, bb->index))
724 for (parm = DECL_ARGUMENTS (current_function_decl);
725 parm && parm != base;
726 parm = DECL_CHAIN (parm))
729 gcc_assert (parm_index < func_param_count);
731 idx = bb->index * func_param_count + parm_index;
732 if (bb_dereferences[idx] < dist)
733 bb_dereferences[idx] = dist;
736 /* Allocate an access structure for BASE, OFFSET and SIZE, clear it, fill in
737 the three fields. Also add it to the vector of accesses corresponding to
738 the base. Finally, return the new access. */
740 static struct access *
741 create_access_1 (tree base, HOST_WIDE_INT offset, HOST_WIDE_INT size)
743 VEC (access_p, heap) *vec;
744 struct access *access;
747 access = (struct access *) pool_alloc (access_pool);
748 memset (access, 0, sizeof (struct access));
750 access->offset = offset;
753 slot = pointer_map_contains (base_access_vec, base);
755 vec = (VEC (access_p, heap) *) *slot;
757 vec = VEC_alloc (access_p, heap, 32);
759 VEC_safe_push (access_p, heap, vec, access);
761 *((struct VEC (access_p,heap) **)
762 pointer_map_insert (base_access_vec, base)) = vec;
767 /* Create and insert access for EXPR. Return created access, or NULL if it is
770 static struct access *
771 create_access (tree expr, gimple stmt, bool write)
773 struct access *access;
774 HOST_WIDE_INT offset, size, max_size;
776 bool ptr, unscalarizable_region = false;
778 base = get_ref_base_and_extent (expr, &offset, &size, &max_size);
780 if (sra_mode == SRA_MODE_EARLY_IPA
781 && TREE_CODE (base) == MEM_REF)
783 base = get_ssa_base_param (TREE_OPERAND (base, 0));
791 if (!DECL_P (base) || !bitmap_bit_p (candidate_bitmap, DECL_UID (base)))
794 if (sra_mode == SRA_MODE_EARLY_IPA)
796 if (size < 0 || size != max_size)
798 disqualify_candidate (base, "Encountered a variable sized access.");
801 if (TREE_CODE (expr) == COMPONENT_REF
802 && DECL_BIT_FIELD (TREE_OPERAND (expr, 1)))
804 disqualify_candidate (base, "Encountered a bit-field access.");
807 gcc_checking_assert ((offset % BITS_PER_UNIT) == 0);
810 mark_parm_dereference (base, offset + size, stmt);
814 if (size != max_size)
817 unscalarizable_region = true;
821 disqualify_candidate (base, "Encountered an unconstrained access.");
826 access = create_access_1 (base, offset, size);
828 access->type = TREE_TYPE (expr);
829 access->write = write;
830 access->grp_unscalarizable_region = unscalarizable_region;
833 if (TREE_CODE (expr) == COMPONENT_REF
834 && DECL_NONADDRESSABLE_P (TREE_OPERAND (expr, 1)))
835 access->non_addressable = 1;
841 /* Return true iff TYPE is a RECORD_TYPE with fields that are either of gimple
842 register types or (recursively) records with only these two kinds of fields.
843 It also returns false if any of these records contains a bit-field. */
846 type_consists_of_records_p (tree type)
850 if (TREE_CODE (type) != RECORD_TYPE)
853 for (fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld))
854 if (TREE_CODE (fld) == FIELD_DECL)
856 tree ft = TREE_TYPE (fld);
858 if (DECL_BIT_FIELD (fld))
861 if (!is_gimple_reg_type (ft)
862 && !type_consists_of_records_p (ft))
869 /* Create total_scalarization accesses for all scalar type fields in DECL that
870 must be of a RECORD_TYPE conforming to type_consists_of_records_p. BASE
871 must be the top-most VAR_DECL representing the variable, OFFSET must be the
872 offset of DECL within BASE. REF must be the memory reference expression for
876 completely_scalarize_record (tree base, tree decl, HOST_WIDE_INT offset,
879 tree fld, decl_type = TREE_TYPE (decl);
881 for (fld = TYPE_FIELDS (decl_type); fld; fld = DECL_CHAIN (fld))
882 if (TREE_CODE (fld) == FIELD_DECL)
884 HOST_WIDE_INT pos = offset + int_bit_position (fld);
885 tree ft = TREE_TYPE (fld);
886 tree nref = build3 (COMPONENT_REF, TREE_TYPE (fld), ref, fld,
889 if (is_gimple_reg_type (ft))
891 struct access *access;
894 size = tree_low_cst (DECL_SIZE (fld), 1);
895 access = create_access_1 (base, pos, size);
898 access->total_scalarization = 1;
899 /* Accesses for intraprocedural SRA can have their stmt NULL. */
902 completely_scalarize_record (base, fld, pos, nref);
907 /* Search the given tree for a declaration by skipping handled components and
908 exclude it from the candidates. */
911 disqualify_base_of_expr (tree t, const char *reason)
913 t = get_base_address (t);
915 && sra_mode == SRA_MODE_EARLY_IPA
916 && TREE_CODE (t) == MEM_REF)
917 t = get_ssa_base_param (TREE_OPERAND (t, 0));
920 disqualify_candidate (t, reason);
923 /* Scan expression EXPR and create access structures for all accesses to
924 candidates for scalarization. Return the created access or NULL if none is
927 static struct access *
928 build_access_from_expr_1 (tree expr, gimple stmt, bool write)
930 struct access *ret = NULL;
933 if (TREE_CODE (expr) == BIT_FIELD_REF
934 || TREE_CODE (expr) == IMAGPART_EXPR
935 || TREE_CODE (expr) == REALPART_EXPR)
937 expr = TREE_OPERAND (expr, 0);
943 /* We need to dive through V_C_Es in order to get the size of its parameter
944 and not the result type. Ada produces such statements. We are also
945 capable of handling the topmost V_C_E but not any of those buried in other
946 handled components. */
947 if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
948 expr = TREE_OPERAND (expr, 0);
950 if (contains_view_convert_expr_p (expr))
952 disqualify_base_of_expr (expr, "V_C_E under a different handled "
957 switch (TREE_CODE (expr))
960 if (TREE_CODE (TREE_OPERAND (expr, 0)) != ADDR_EXPR
961 && sra_mode != SRA_MODE_EARLY_IPA)
969 case ARRAY_RANGE_REF:
970 ret = create_access (expr, stmt, write);
977 if (write && partial_ref && ret)
978 ret->grp_partial_lhs = 1;
983 /* Scan expression EXPR and create access structures for all accesses to
984 candidates for scalarization. Return true if any access has been inserted.
985 STMT must be the statement from which the expression is taken, WRITE must be
986 true if the expression is a store and false otherwise. */
989 build_access_from_expr (tree expr, gimple stmt, bool write)
991 struct access *access;
993 access = build_access_from_expr_1 (expr, stmt, write);
996 /* This means the aggregate is accesses as a whole in a way other than an
997 assign statement and thus cannot be removed even if we had a scalar
998 replacement for everything. */
999 if (cannot_scalarize_away_bitmap)
1000 bitmap_set_bit (cannot_scalarize_away_bitmap, DECL_UID (access->base));
1006 /* Disqualify LHS and RHS for scalarization if STMT must end its basic block in
1007 modes in which it matters, return true iff they have been disqualified. RHS
1008 may be NULL, in that case ignore it. If we scalarize an aggregate in
1009 intra-SRA we may need to add statements after each statement. This is not
1010 possible if a statement unconditionally has to end the basic block. */
1012 disqualify_ops_if_throwing_stmt (gimple stmt, tree lhs, tree rhs)
1014 if ((sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA)
1015 && (stmt_can_throw_internal (stmt) || stmt_ends_bb_p (stmt)))
1017 disqualify_base_of_expr (lhs, "LHS of a throwing stmt.");
1019 disqualify_base_of_expr (rhs, "RHS of a throwing stmt.");
1025 /* Return true if EXP is a memory reference less aligned than ALIGN. This is
1026 invoked only on strict-alignment targets. */
1029 tree_non_aligned_mem_p (tree exp, unsigned int align)
1031 unsigned int exp_align;
1033 if (TREE_CODE (exp) == VIEW_CONVERT_EXPR)
1034 exp = TREE_OPERAND (exp, 0);
1036 if (TREE_CODE (exp) == SSA_NAME || is_gimple_min_invariant (exp))
1039 /* get_object_alignment will fall back to BITS_PER_UNIT if it cannot
1040 compute an explicit alignment. Pretend that dereferenced pointers
1041 are always aligned on strict-alignment targets. */
1042 exp_align = get_object_alignment (exp, BIGGEST_ALIGNMENT);
1043 if (TREE_CODE (exp) == MEM_REF || TREE_CODE (exp) == TARGET_MEM_REF)
1044 exp_align = MAX (TYPE_ALIGN (TREE_TYPE (exp)), exp_align);
1046 if (exp_align < align)
1052 /* Return true if EXP is a memory reference less aligned than what the access
1053 ACC would require. This is invoked only on strict-alignment targets. */
1056 tree_non_aligned_mem_for_access_p (tree exp, struct access *acc)
1058 unsigned int acc_align;
1060 /* The alignment of the access is that of its expression. However, it may
1061 have been artificially increased, e.g. by a local alignment promotion,
1062 so we cap it to the alignment of the type of the base, on the grounds
1063 that valid sub-accesses cannot be more aligned than that. */
1064 acc_align = get_object_alignment (acc->expr, BIGGEST_ALIGNMENT);
1065 if (acc->base && acc_align > TYPE_ALIGN (TREE_TYPE (acc->base)))
1066 acc_align = TYPE_ALIGN (TREE_TYPE (acc->base));
1068 return tree_non_aligned_mem_p (exp, acc_align);
1071 /* Scan expressions occuring in STMT, create access structures for all accesses
1072 to candidates for scalarization and remove those candidates which occur in
1073 statements or expressions that prevent them from being split apart. Return
1074 true if any access has been inserted. */
1077 build_accesses_from_assign (gimple stmt)
1080 struct access *lacc, *racc;
1082 if (!gimple_assign_single_p (stmt))
1085 lhs = gimple_assign_lhs (stmt);
1086 rhs = gimple_assign_rhs1 (stmt);
1088 if (disqualify_ops_if_throwing_stmt (stmt, lhs, rhs))
1091 racc = build_access_from_expr_1 (rhs, stmt, false);
1092 lacc = build_access_from_expr_1 (lhs, stmt, true);
1096 lacc->grp_assignment_write = 1;
1097 if (STRICT_ALIGNMENT && tree_non_aligned_mem_for_access_p (rhs, lacc))
1098 lacc->grp_unscalarizable_region = 1;
1103 racc->grp_assignment_read = 1;
1104 if (should_scalarize_away_bitmap && !gimple_has_volatile_ops (stmt)
1105 && !is_gimple_reg_type (racc->type))
1106 bitmap_set_bit (should_scalarize_away_bitmap, DECL_UID (racc->base));
1107 if (STRICT_ALIGNMENT && tree_non_aligned_mem_for_access_p (lhs, racc))
1108 racc->grp_unscalarizable_region = 1;
1112 && (sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA)
1113 && !lacc->grp_unscalarizable_region
1114 && !racc->grp_unscalarizable_region
1115 && AGGREGATE_TYPE_P (TREE_TYPE (lhs))
1116 /* FIXME: Turn the following line into an assert after PR 40058 is
1118 && lacc->size == racc->size
1119 && useless_type_conversion_p (lacc->type, racc->type))
1121 struct assign_link *link;
1123 link = (struct assign_link *) pool_alloc (link_pool);
1124 memset (link, 0, sizeof (struct assign_link));
1129 add_link_to_rhs (racc, link);
1132 return lacc || racc;
1135 /* Callback of walk_stmt_load_store_addr_ops visit_addr used to determine
1136 GIMPLE_ASM operands with memory constrains which cannot be scalarized. */
1139 asm_visit_addr (gimple stmt ATTRIBUTE_UNUSED, tree op,
1140 void *data ATTRIBUTE_UNUSED)
1142 op = get_base_address (op);
1145 disqualify_candidate (op, "Non-scalarizable GIMPLE_ASM operand.");
1150 /* Return true iff callsite CALL has at least as many actual arguments as there
1151 are formal parameters of the function currently processed by IPA-SRA. */
1154 callsite_has_enough_arguments_p (gimple call)
1156 return gimple_call_num_args (call) >= (unsigned) func_param_count;
1159 /* Scan function and look for interesting expressions and create access
1160 structures for them. Return true iff any access is created. */
1163 scan_function (void)
1170 gimple_stmt_iterator gsi;
1171 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1173 gimple stmt = gsi_stmt (gsi);
1177 if (final_bbs && stmt_can_throw_external (stmt))
1178 bitmap_set_bit (final_bbs, bb->index);
1179 switch (gimple_code (stmt))
1182 t = gimple_return_retval (stmt);
1184 ret |= build_access_from_expr (t, stmt, false);
1186 bitmap_set_bit (final_bbs, bb->index);
1190 ret |= build_accesses_from_assign (stmt);
1194 for (i = 0; i < gimple_call_num_args (stmt); i++)
1195 ret |= build_access_from_expr (gimple_call_arg (stmt, i),
1198 if (sra_mode == SRA_MODE_EARLY_IPA)
1200 tree dest = gimple_call_fndecl (stmt);
1201 int flags = gimple_call_flags (stmt);
1205 if (DECL_BUILT_IN_CLASS (dest) == BUILT_IN_NORMAL
1206 && DECL_FUNCTION_CODE (dest) == BUILT_IN_APPLY_ARGS)
1207 encountered_apply_args = true;
1208 if (cgraph_get_node (dest)
1209 == cgraph_get_node (current_function_decl))
1211 encountered_recursive_call = true;
1212 if (!callsite_has_enough_arguments_p (stmt))
1213 encountered_unchangable_recursive_call = true;
1218 && (flags & (ECF_CONST | ECF_PURE)) == 0)
1219 bitmap_set_bit (final_bbs, bb->index);
1222 t = gimple_call_lhs (stmt);
1223 if (t && !disqualify_ops_if_throwing_stmt (stmt, t, NULL))
1224 ret |= build_access_from_expr (t, stmt, true);
1228 walk_stmt_load_store_addr_ops (stmt, NULL, NULL, NULL,
1231 bitmap_set_bit (final_bbs, bb->index);
1233 for (i = 0; i < gimple_asm_ninputs (stmt); i++)
1235 t = TREE_VALUE (gimple_asm_input_op (stmt, i));
1236 ret |= build_access_from_expr (t, stmt, false);
1238 for (i = 0; i < gimple_asm_noutputs (stmt); i++)
1240 t = TREE_VALUE (gimple_asm_output_op (stmt, i));
1241 ret |= build_access_from_expr (t, stmt, true);
1254 /* Helper of QSORT function. There are pointers to accesses in the array. An
1255 access is considered smaller than another if it has smaller offset or if the
1256 offsets are the same but is size is bigger. */
1259 compare_access_positions (const void *a, const void *b)
1261 const access_p *fp1 = (const access_p *) a;
1262 const access_p *fp2 = (const access_p *) b;
1263 const access_p f1 = *fp1;
1264 const access_p f2 = *fp2;
1266 if (f1->offset != f2->offset)
1267 return f1->offset < f2->offset ? -1 : 1;
1269 if (f1->size == f2->size)
1271 if (f1->type == f2->type)
1273 /* Put any non-aggregate type before any aggregate type. */
1274 else if (!is_gimple_reg_type (f1->type)
1275 && is_gimple_reg_type (f2->type))
1277 else if (is_gimple_reg_type (f1->type)
1278 && !is_gimple_reg_type (f2->type))
1280 /* Put any complex or vector type before any other scalar type. */
1281 else if (TREE_CODE (f1->type) != COMPLEX_TYPE
1282 && TREE_CODE (f1->type) != VECTOR_TYPE
1283 && (TREE_CODE (f2->type) == COMPLEX_TYPE
1284 || TREE_CODE (f2->type) == VECTOR_TYPE))
1286 else if ((TREE_CODE (f1->type) == COMPLEX_TYPE
1287 || TREE_CODE (f1->type) == VECTOR_TYPE)
1288 && TREE_CODE (f2->type) != COMPLEX_TYPE
1289 && TREE_CODE (f2->type) != VECTOR_TYPE)
1291 /* Put the integral type with the bigger precision first. */
1292 else if (INTEGRAL_TYPE_P (f1->type)
1293 && INTEGRAL_TYPE_P (f2->type))
1294 return TYPE_PRECISION (f2->type) - TYPE_PRECISION (f1->type);
1295 /* Put any integral type with non-full precision last. */
1296 else if (INTEGRAL_TYPE_P (f1->type)
1297 && (TREE_INT_CST_LOW (TYPE_SIZE (f1->type))
1298 != TYPE_PRECISION (f1->type)))
1300 else if (INTEGRAL_TYPE_P (f2->type)
1301 && (TREE_INT_CST_LOW (TYPE_SIZE (f2->type))
1302 != TYPE_PRECISION (f2->type)))
1304 /* Stabilize the sort. */
1305 return TYPE_UID (f1->type) - TYPE_UID (f2->type);
1308 /* We want the bigger accesses first, thus the opposite operator in the next
1310 return f1->size > f2->size ? -1 : 1;
1314 /* Append a name of the declaration to the name obstack. A helper function for
1318 make_fancy_decl_name (tree decl)
1322 tree name = DECL_NAME (decl);
1324 obstack_grow (&name_obstack, IDENTIFIER_POINTER (name),
1325 IDENTIFIER_LENGTH (name));
1328 sprintf (buffer, "D%u", DECL_UID (decl));
1329 obstack_grow (&name_obstack, buffer, strlen (buffer));
1333 /* Helper for make_fancy_name. */
1336 make_fancy_name_1 (tree expr)
1343 make_fancy_decl_name (expr);
1347 switch (TREE_CODE (expr))
1350 make_fancy_name_1 (TREE_OPERAND (expr, 0));
1351 obstack_1grow (&name_obstack, '$');
1352 make_fancy_decl_name (TREE_OPERAND (expr, 1));
1356 make_fancy_name_1 (TREE_OPERAND (expr, 0));
1357 obstack_1grow (&name_obstack, '$');
1358 /* Arrays with only one element may not have a constant as their
1360 index = TREE_OPERAND (expr, 1);
1361 if (TREE_CODE (index) != INTEGER_CST)
1363 sprintf (buffer, HOST_WIDE_INT_PRINT_DEC, TREE_INT_CST_LOW (index));
1364 obstack_grow (&name_obstack, buffer, strlen (buffer));
1368 make_fancy_name_1 (TREE_OPERAND (expr, 0));
1372 make_fancy_name_1 (TREE_OPERAND (expr, 0));
1373 if (!integer_zerop (TREE_OPERAND (expr, 1)))
1375 obstack_1grow (&name_obstack, '$');
1376 sprintf (buffer, HOST_WIDE_INT_PRINT_DEC,
1377 TREE_INT_CST_LOW (TREE_OPERAND (expr, 1)));
1378 obstack_grow (&name_obstack, buffer, strlen (buffer));
1385 gcc_unreachable (); /* we treat these as scalars. */
1392 /* Create a human readable name for replacement variable of ACCESS. */
1395 make_fancy_name (tree expr)
1397 make_fancy_name_1 (expr);
1398 obstack_1grow (&name_obstack, '\0');
1399 return XOBFINISH (&name_obstack, char *);
1402 /* Construct a MEM_REF that would reference a part of aggregate BASE of type
1403 EXP_TYPE at the given OFFSET. If BASE is something for which
1404 get_addr_base_and_unit_offset returns NULL, gsi must be non-NULL and is used
1405 to insert new statements either before or below the current one as specified
1406 by INSERT_AFTER. This function is not capable of handling bitfields. */
1409 build_ref_for_offset (location_t loc, tree base, HOST_WIDE_INT offset,
1410 tree exp_type, gimple_stmt_iterator *gsi,
1413 tree prev_base = base;
1415 HOST_WIDE_INT base_offset;
1417 gcc_checking_assert (offset % BITS_PER_UNIT == 0);
1419 base = get_addr_base_and_unit_offset (base, &base_offset);
1421 /* get_addr_base_and_unit_offset returns NULL for references with a variable
1422 offset such as array[var_index]. */
1428 gcc_checking_assert (gsi);
1429 tmp = create_tmp_reg (build_pointer_type (TREE_TYPE (prev_base)), NULL);
1430 add_referenced_var (tmp);
1431 tmp = make_ssa_name (tmp, NULL);
1432 addr = build_fold_addr_expr (unshare_expr (prev_base));
1433 stmt = gimple_build_assign (tmp, addr);
1434 gimple_set_location (stmt, loc);
1435 SSA_NAME_DEF_STMT (tmp) = stmt;
1437 gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
1439 gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
1442 off = build_int_cst (reference_alias_ptr_type (prev_base),
1443 offset / BITS_PER_UNIT);
1446 else if (TREE_CODE (base) == MEM_REF)
1448 off = build_int_cst (TREE_TYPE (TREE_OPERAND (base, 1)),
1449 base_offset + offset / BITS_PER_UNIT);
1450 off = int_const_binop (PLUS_EXPR, TREE_OPERAND (base, 1), off, 0);
1451 base = unshare_expr (TREE_OPERAND (base, 0));
1455 off = build_int_cst (reference_alias_ptr_type (base),
1456 base_offset + offset / BITS_PER_UNIT);
1457 base = build_fold_addr_expr (unshare_expr (base));
1460 return fold_build2_loc (loc, MEM_REF, exp_type, base, off);
1463 DEF_VEC_ALLOC_P_STACK (tree);
1464 #define VEC_tree_stack_alloc(alloc) VEC_stack_alloc (tree, alloc)
1466 /* Construct a memory reference to a part of an aggregate BASE at the given
1467 OFFSET and of the type of MODEL. In case this is a chain of references
1468 to component, the function will replicate the chain of COMPONENT_REFs of
1469 the expression of MODEL to access it. GSI and INSERT_AFTER have the same
1470 meaning as in build_ref_for_offset. */
1473 build_ref_for_model (location_t loc, tree base, HOST_WIDE_INT offset,
1474 struct access *model, gimple_stmt_iterator *gsi,
1477 tree type = model->type, t;
1478 VEC(tree,stack) *cr_stack = NULL;
1480 if (TREE_CODE (model->expr) == COMPONENT_REF)
1482 tree expr = model->expr;
1484 /* Create a stack of the COMPONENT_REFs so later we can walk them in
1485 order from inner to outer. */
1486 cr_stack = VEC_alloc (tree, stack, 6);
1489 tree field = TREE_OPERAND (expr, 1);
1490 HOST_WIDE_INT bit_pos = int_bit_position (field);
1492 /* We can be called with a model different from the one associated
1493 with BASE so we need to avoid going up the chain too far. */
1494 if (offset - bit_pos < 0)
1498 VEC_safe_push (tree, stack, cr_stack, expr);
1500 expr = TREE_OPERAND (expr, 0);
1501 type = TREE_TYPE (expr);
1502 } while (TREE_CODE (expr) == COMPONENT_REF);
1505 t = build_ref_for_offset (loc, base, offset, type, gsi, insert_after);
1507 if (TREE_CODE (model->expr) == COMPONENT_REF)
1512 /* Now replicate the chain of COMPONENT_REFs from inner to outer. */
1513 FOR_EACH_VEC_ELT_REVERSE (tree, cr_stack, i, expr)
1515 tree field = TREE_OPERAND (expr, 1);
1516 t = fold_build3_loc (loc, COMPONENT_REF, TREE_TYPE (field), t, field,
1520 VEC_free (tree, stack, cr_stack);
1526 /* Construct a memory reference consisting of component_refs and array_refs to
1527 a part of an aggregate *RES (which is of type TYPE). The requested part
1528 should have type EXP_TYPE at be the given OFFSET. This function might not
1529 succeed, it returns true when it does and only then *RES points to something
1530 meaningful. This function should be used only to build expressions that we
1531 might need to present to user (e.g. in warnings). In all other situations,
1532 build_ref_for_model or build_ref_for_offset should be used instead. */
1535 build_user_friendly_ref_for_offset (tree *res, tree type, HOST_WIDE_INT offset,
1541 tree tr_size, index, minidx;
1542 HOST_WIDE_INT el_size;
1544 if (offset == 0 && exp_type
1545 && types_compatible_p (exp_type, type))
1548 switch (TREE_CODE (type))
1551 case QUAL_UNION_TYPE:
1553 for (fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld))
1555 HOST_WIDE_INT pos, size;
1556 tree expr, *expr_ptr;
1558 if (TREE_CODE (fld) != FIELD_DECL)
1561 pos = int_bit_position (fld);
1562 gcc_assert (TREE_CODE (type) == RECORD_TYPE || pos == 0);
1563 tr_size = DECL_SIZE (fld);
1564 if (!tr_size || !host_integerp (tr_size, 1))
1566 size = tree_low_cst (tr_size, 1);
1572 else if (pos > offset || (pos + size) <= offset)
1575 expr = build3 (COMPONENT_REF, TREE_TYPE (fld), *res, fld,
1578 if (build_user_friendly_ref_for_offset (expr_ptr, TREE_TYPE (fld),
1579 offset - pos, exp_type))
1588 tr_size = TYPE_SIZE (TREE_TYPE (type));
1589 if (!tr_size || !host_integerp (tr_size, 1))
1591 el_size = tree_low_cst (tr_size, 1);
1593 minidx = TYPE_MIN_VALUE (TYPE_DOMAIN (type));
1594 if (TREE_CODE (minidx) != INTEGER_CST || el_size == 0)
1596 index = build_int_cst (TYPE_DOMAIN (type), offset / el_size);
1597 if (!integer_zerop (minidx))
1598 index = int_const_binop (PLUS_EXPR, index, minidx, 0);
1599 *res = build4 (ARRAY_REF, TREE_TYPE (type), *res, index,
1600 NULL_TREE, NULL_TREE);
1601 offset = offset % el_size;
1602 type = TREE_TYPE (type);
1617 /* Return true iff TYPE is stdarg va_list type. */
1620 is_va_list_type (tree type)
1622 return TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (va_list_type_node);
1625 /* The very first phase of intraprocedural SRA. It marks in candidate_bitmap
1626 those with type which is suitable for scalarization. */
1629 find_var_candidates (void)
1632 referenced_var_iterator rvi;
1635 FOR_EACH_REFERENCED_VAR (cfun, var, rvi)
1637 if (TREE_CODE (var) != VAR_DECL && TREE_CODE (var) != PARM_DECL)
1639 type = TREE_TYPE (var);
1641 if (!AGGREGATE_TYPE_P (type)
1642 || needs_to_live_in_memory (var)
1643 || TREE_THIS_VOLATILE (var)
1644 || !COMPLETE_TYPE_P (type)
1645 || !host_integerp (TYPE_SIZE (type), 1)
1646 || tree_low_cst (TYPE_SIZE (type), 1) == 0
1647 || type_internals_preclude_sra_p (type)
1648 /* Fix for PR 41089. tree-stdarg.c needs to have va_lists intact but
1649 we also want to schedule it rather late. Thus we ignore it in
1651 || (sra_mode == SRA_MODE_EARLY_INTRA
1652 && is_va_list_type (type)))
1655 bitmap_set_bit (candidate_bitmap, DECL_UID (var));
1657 if (dump_file && (dump_flags & TDF_DETAILS))
1659 fprintf (dump_file, "Candidate (%d): ", DECL_UID (var));
1660 print_generic_expr (dump_file, var, 0);
1661 fprintf (dump_file, "\n");
1669 /* Sort all accesses for the given variable, check for partial overlaps and
1670 return NULL if there are any. If there are none, pick a representative for
1671 each combination of offset and size and create a linked list out of them.
1672 Return the pointer to the first representative and make sure it is the first
1673 one in the vector of accesses. */
1675 static struct access *
1676 sort_and_splice_var_accesses (tree var)
1678 int i, j, access_count;
1679 struct access *res, **prev_acc_ptr = &res;
1680 VEC (access_p, heap) *access_vec;
1682 HOST_WIDE_INT low = -1, high = 0;
1684 access_vec = get_base_access_vector (var);
1687 access_count = VEC_length (access_p, access_vec);
1689 /* Sort by <OFFSET, SIZE>. */
1690 VEC_qsort (access_p, access_vec, compare_access_positions);
1693 while (i < access_count)
1695 struct access *access = VEC_index (access_p, access_vec, i);
1696 bool grp_write = access->write;
1697 bool grp_read = !access->write;
1698 bool grp_scalar_write = access->write
1699 && is_gimple_reg_type (access->type);
1700 bool grp_scalar_read = !access->write
1701 && is_gimple_reg_type (access->type);
1702 bool grp_assignment_read = access->grp_assignment_read;
1703 bool grp_assignment_write = access->grp_assignment_write;
1704 bool multiple_scalar_reads = false;
1705 bool total_scalarization = access->total_scalarization;
1706 bool grp_partial_lhs = access->grp_partial_lhs;
1707 bool first_scalar = is_gimple_reg_type (access->type);
1708 bool unscalarizable_region = access->grp_unscalarizable_region;
1710 if (first || access->offset >= high)
1713 low = access->offset;
1714 high = access->offset + access->size;
1716 else if (access->offset > low && access->offset + access->size > high)
1719 gcc_assert (access->offset >= low
1720 && access->offset + access->size <= high);
1723 while (j < access_count)
1725 struct access *ac2 = VEC_index (access_p, access_vec, j);
1726 if (ac2->offset != access->offset || ac2->size != access->size)
1731 grp_scalar_write = (grp_scalar_write
1732 || is_gimple_reg_type (ac2->type));
1737 if (is_gimple_reg_type (ac2->type))
1739 if (grp_scalar_read)
1740 multiple_scalar_reads = true;
1742 grp_scalar_read = true;
1745 grp_assignment_read |= ac2->grp_assignment_read;
1746 grp_assignment_write |= ac2->grp_assignment_write;
1747 grp_partial_lhs |= ac2->grp_partial_lhs;
1748 unscalarizable_region |= ac2->grp_unscalarizable_region;
1749 total_scalarization |= ac2->total_scalarization;
1750 relink_to_new_repr (access, ac2);
1752 /* If there are both aggregate-type and scalar-type accesses with
1753 this combination of size and offset, the comparison function
1754 should have put the scalars first. */
1755 gcc_assert (first_scalar || !is_gimple_reg_type (ac2->type));
1756 ac2->group_representative = access;
1762 access->group_representative = access;
1763 access->grp_write = grp_write;
1764 access->grp_read = grp_read;
1765 access->grp_scalar_read = grp_scalar_read;
1766 access->grp_scalar_write = grp_scalar_write;
1767 access->grp_assignment_read = grp_assignment_read;
1768 access->grp_assignment_write = grp_assignment_write;
1769 access->grp_hint = multiple_scalar_reads || total_scalarization;
1770 access->grp_partial_lhs = grp_partial_lhs;
1771 access->grp_unscalarizable_region = unscalarizable_region;
1772 if (access->first_link)
1773 add_access_to_work_queue (access);
1775 *prev_acc_ptr = access;
1776 prev_acc_ptr = &access->next_grp;
1779 gcc_assert (res == VEC_index (access_p, access_vec, 0));
1783 /* Create a variable for the given ACCESS which determines the type, name and a
1784 few other properties. Return the variable declaration and store it also to
1785 ACCESS->replacement. */
1788 create_access_replacement (struct access *access, bool rename)
1792 repl = create_tmp_var (access->type, "SR");
1794 add_referenced_var (repl);
1796 mark_sym_for_renaming (repl);
1798 if (!access->grp_partial_lhs
1799 && (TREE_CODE (access->type) == COMPLEX_TYPE
1800 || TREE_CODE (access->type) == VECTOR_TYPE))
1801 DECL_GIMPLE_REG_P (repl) = 1;
1803 DECL_SOURCE_LOCATION (repl) = DECL_SOURCE_LOCATION (access->base);
1804 DECL_ARTIFICIAL (repl) = 1;
1805 DECL_IGNORED_P (repl) = DECL_IGNORED_P (access->base);
1807 if (DECL_NAME (access->base)
1808 && !DECL_IGNORED_P (access->base)
1809 && !DECL_ARTIFICIAL (access->base))
1811 char *pretty_name = make_fancy_name (access->expr);
1812 tree debug_expr = unshare_expr (access->expr), d;
1814 DECL_NAME (repl) = get_identifier (pretty_name);
1815 obstack_free (&name_obstack, pretty_name);
1817 /* Get rid of any SSA_NAMEs embedded in debug_expr,
1818 as DECL_DEBUG_EXPR isn't considered when looking for still
1819 used SSA_NAMEs and thus they could be freed. All debug info
1820 generation cares is whether something is constant or variable
1821 and that get_ref_base_and_extent works properly on the
1823 for (d = debug_expr; handled_component_p (d); d = TREE_OPERAND (d, 0))
1824 switch (TREE_CODE (d))
1827 case ARRAY_RANGE_REF:
1828 if (TREE_OPERAND (d, 1)
1829 && TREE_CODE (TREE_OPERAND (d, 1)) == SSA_NAME)
1830 TREE_OPERAND (d, 1) = SSA_NAME_VAR (TREE_OPERAND (d, 1));
1831 if (TREE_OPERAND (d, 3)
1832 && TREE_CODE (TREE_OPERAND (d, 3)) == SSA_NAME)
1833 TREE_OPERAND (d, 3) = SSA_NAME_VAR (TREE_OPERAND (d, 3));
1836 if (TREE_OPERAND (d, 2)
1837 && TREE_CODE (TREE_OPERAND (d, 2)) == SSA_NAME)
1838 TREE_OPERAND (d, 2) = SSA_NAME_VAR (TREE_OPERAND (d, 2));
1843 SET_DECL_DEBUG_EXPR (repl, debug_expr);
1844 DECL_DEBUG_EXPR_IS_FROM (repl) = 1;
1845 if (access->grp_no_warning)
1846 TREE_NO_WARNING (repl) = 1;
1848 TREE_NO_WARNING (repl) = TREE_NO_WARNING (access->base);
1851 TREE_NO_WARNING (repl) = 1;
1855 fprintf (dump_file, "Created a replacement for ");
1856 print_generic_expr (dump_file, access->base, 0);
1857 fprintf (dump_file, " offset: %u, size: %u: ",
1858 (unsigned) access->offset, (unsigned) access->size);
1859 print_generic_expr (dump_file, repl, 0);
1860 fprintf (dump_file, "\n");
1862 sra_stats.replacements++;
1867 /* Return ACCESS scalar replacement, create it if it does not exist yet. */
1870 get_access_replacement (struct access *access)
1872 gcc_assert (access->grp_to_be_replaced);
1874 if (!access->replacement_decl)
1875 access->replacement_decl = create_access_replacement (access, true);
1876 return access->replacement_decl;
1879 /* Return ACCESS scalar replacement, create it if it does not exist yet but do
1880 not mark it for renaming. */
1883 get_unrenamed_access_replacement (struct access *access)
1885 gcc_assert (!access->grp_to_be_replaced);
1887 if (!access->replacement_decl)
1888 access->replacement_decl = create_access_replacement (access, false);
1889 return access->replacement_decl;
1893 /* Build a subtree of accesses rooted in *ACCESS, and move the pointer in the
1894 linked list along the way. Stop when *ACCESS is NULL or the access pointed
1895 to it is not "within" the root. Return false iff some accesses partially
1899 build_access_subtree (struct access **access)
1901 struct access *root = *access, *last_child = NULL;
1902 HOST_WIDE_INT limit = root->offset + root->size;
1904 *access = (*access)->next_grp;
1905 while (*access && (*access)->offset + (*access)->size <= limit)
1908 root->first_child = *access;
1910 last_child->next_sibling = *access;
1911 last_child = *access;
1913 if (!build_access_subtree (access))
1917 if (*access && (*access)->offset < limit)
1923 /* Build a tree of access representatives, ACCESS is the pointer to the first
1924 one, others are linked in a list by the next_grp field. Return false iff
1925 some accesses partially overlap. */
1928 build_access_trees (struct access *access)
1932 struct access *root = access;
1934 if (!build_access_subtree (&access))
1936 root->next_grp = access;
1941 /* Return true if expr contains some ARRAY_REFs into a variable bounded
1945 expr_with_var_bounded_array_refs_p (tree expr)
1947 while (handled_component_p (expr))
1949 if (TREE_CODE (expr) == ARRAY_REF
1950 && !host_integerp (array_ref_low_bound (expr), 0))
1952 expr = TREE_OPERAND (expr, 0);
1957 enum mark_rw_status { SRA_MRRW_NOTHING, SRA_MRRW_DIRECT, SRA_MRRW_ASSIGN};
1959 /* Analyze the subtree of accesses rooted in ROOT, scheduling replacements when
1960 both seeming beneficial and when ALLOW_REPLACEMENTS allows it. Also set all
1961 sorts of access flags appropriately along the way, notably always set
1962 grp_read and grp_assign_read according to MARK_READ and grp_write when
1965 Creating a replacement for a scalar access is considered beneficial if its
1966 grp_hint is set (this means we are either attempting total scalarization or
1967 there is more than one direct read access) or according to the following
1970 Access written to through a scalar type (once or more times)
1972 | Written to in an assignment statement
1974 | | Access read as scalar _once_
1976 | | | Read in an assignment statement
1978 | | | | Scalarize Comment
1979 -----------------------------------------------------------------------------
1980 0 0 0 0 No access for the scalar
1981 0 0 0 1 No access for the scalar
1982 0 0 1 0 No Single read - won't help
1983 0 0 1 1 No The same case
1984 0 1 0 0 No access for the scalar
1985 0 1 0 1 No access for the scalar
1986 0 1 1 0 Yes s = *g; return s.i;
1987 0 1 1 1 Yes The same case as above
1988 1 0 0 0 No Won't help
1989 1 0 0 1 Yes s.i = 1; *g = s;
1990 1 0 1 0 Yes s.i = 5; g = s.i;
1991 1 0 1 1 Yes The same case as above
1992 1 1 0 0 No Won't help.
1993 1 1 0 1 Yes s.i = 1; *g = s;
1994 1 1 1 0 Yes s = *g; return s.i;
1995 1 1 1 1 Yes Any of the above yeses */
1998 analyze_access_subtree (struct access *root, bool allow_replacements,
1999 enum mark_rw_status mark_read,
2000 enum mark_rw_status mark_write)
2002 struct access *child;
2003 HOST_WIDE_INT limit = root->offset + root->size;
2004 HOST_WIDE_INT covered_to = root->offset;
2005 bool scalar = is_gimple_reg_type (root->type);
2006 bool hole = false, sth_created = false;
2008 if (root->grp_assignment_read)
2009 mark_read = SRA_MRRW_ASSIGN;
2010 else if (mark_read == SRA_MRRW_ASSIGN)
2013 root->grp_assignment_read = 1;
2015 else if (mark_read == SRA_MRRW_DIRECT)
2017 else if (root->grp_read)
2018 mark_read = SRA_MRRW_DIRECT;
2020 if (root->grp_assignment_write)
2021 mark_write = SRA_MRRW_ASSIGN;
2022 else if (mark_write == SRA_MRRW_ASSIGN)
2024 root->grp_write = 1;
2025 root->grp_assignment_write = 1;
2027 else if (mark_write == SRA_MRRW_DIRECT)
2028 root->grp_write = 1;
2029 else if (root->grp_write)
2030 mark_write = SRA_MRRW_DIRECT;
2032 if (root->grp_unscalarizable_region)
2033 allow_replacements = false;
2035 if (allow_replacements && expr_with_var_bounded_array_refs_p (root->expr))
2036 allow_replacements = false;
2038 for (child = root->first_child; child; child = child->next_sibling)
2040 if (!hole && child->offset < covered_to)
2043 covered_to += child->size;
2045 sth_created |= analyze_access_subtree (child,
2046 allow_replacements && !scalar,
2047 mark_read, mark_write);
2049 root->grp_unscalarized_data |= child->grp_unscalarized_data;
2050 hole |= !child->grp_covered;
2053 if (allow_replacements && scalar && !root->first_child
2055 || ((root->grp_scalar_read || root->grp_assignment_read)
2056 && (root->grp_scalar_write || root->grp_assignment_write))))
2058 bool new_integer_type;
2059 if (TREE_CODE (root->type) == ENUMERAL_TYPE)
2061 tree rt = root->type;
2062 root->type = build_nonstandard_integer_type (TYPE_PRECISION (rt),
2063 TYPE_UNSIGNED (rt));
2064 new_integer_type = true;
2067 new_integer_type = false;
2069 if (dump_file && (dump_flags & TDF_DETAILS))
2071 fprintf (dump_file, "Marking ");
2072 print_generic_expr (dump_file, root->base, 0);
2073 fprintf (dump_file, " offset: %u, size: %u ",
2074 (unsigned) root->offset, (unsigned) root->size);
2075 fprintf (dump_file, " to be replaced%s.\n",
2076 new_integer_type ? " with an integer": "");
2079 root->grp_to_be_replaced = 1;
2083 else if (covered_to < limit)
2086 if (sth_created && !hole)
2088 root->grp_covered = 1;
2091 if (root->grp_write || TREE_CODE (root->base) == PARM_DECL)
2092 root->grp_unscalarized_data = 1; /* not covered and written to */
2098 /* Analyze all access trees linked by next_grp by the means of
2099 analyze_access_subtree. */
2101 analyze_access_trees (struct access *access)
2107 if (analyze_access_subtree (access, true,
2108 SRA_MRRW_NOTHING, SRA_MRRW_NOTHING))
2110 access = access->next_grp;
2116 /* Return true iff a potential new child of LACC at offset OFFSET and with size
2117 SIZE would conflict with an already existing one. If exactly such a child
2118 already exists in LACC, store a pointer to it in EXACT_MATCH. */
2121 child_would_conflict_in_lacc (struct access *lacc, HOST_WIDE_INT norm_offset,
2122 HOST_WIDE_INT size, struct access **exact_match)
2124 struct access *child;
2126 for (child = lacc->first_child; child; child = child->next_sibling)
2128 if (child->offset == norm_offset && child->size == size)
2130 *exact_match = child;
2134 if (child->offset < norm_offset + size
2135 && child->offset + child->size > norm_offset)
2142 /* Create a new child access of PARENT, with all properties just like MODEL
2143 except for its offset and with its grp_write false and grp_read true.
2144 Return the new access or NULL if it cannot be created. Note that this access
2145 is created long after all splicing and sorting, it's not located in any
2146 access vector and is automatically a representative of its group. */
2148 static struct access *
2149 create_artificial_child_access (struct access *parent, struct access *model,
2150 HOST_WIDE_INT new_offset)
2152 struct access *access;
2153 struct access **child;
2154 tree expr = parent->base;
2156 gcc_assert (!model->grp_unscalarizable_region);
2158 access = (struct access *) pool_alloc (access_pool);
2159 memset (access, 0, sizeof (struct access));
2160 if (!build_user_friendly_ref_for_offset (&expr, TREE_TYPE (expr), new_offset,
2163 access->grp_no_warning = true;
2164 expr = build_ref_for_model (EXPR_LOCATION (parent->base), parent->base,
2165 new_offset, model, NULL, false);
2168 access->base = parent->base;
2169 access->expr = expr;
2170 access->offset = new_offset;
2171 access->size = model->size;
2172 access->type = model->type;
2173 access->grp_write = true;
2174 access->grp_read = false;
2176 child = &parent->first_child;
2177 while (*child && (*child)->offset < new_offset)
2178 child = &(*child)->next_sibling;
2180 access->next_sibling = *child;
2187 /* Propagate all subaccesses of RACC across an assignment link to LACC. Return
2188 true if any new subaccess was created. Additionally, if RACC is a scalar
2189 access but LACC is not, change the type of the latter, if possible. */
2192 propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
2194 struct access *rchild;
2195 HOST_WIDE_INT norm_delta = lacc->offset - racc->offset;
2198 if (is_gimple_reg_type (lacc->type)
2199 || lacc->grp_unscalarizable_region
2200 || racc->grp_unscalarizable_region)
2203 if (!lacc->first_child && !racc->first_child
2204 && is_gimple_reg_type (racc->type))
2206 tree t = lacc->base;
2208 lacc->type = racc->type;
2209 if (build_user_friendly_ref_for_offset (&t, TREE_TYPE (t), lacc->offset,
2214 lacc->expr = build_ref_for_model (EXPR_LOCATION (lacc->base),
2215 lacc->base, lacc->offset,
2217 lacc->grp_no_warning = true;
2222 for (rchild = racc->first_child; rchild; rchild = rchild->next_sibling)
2224 struct access *new_acc = NULL;
2225 HOST_WIDE_INT norm_offset = rchild->offset + norm_delta;
2227 if (rchild->grp_unscalarizable_region)
2230 if (child_would_conflict_in_lacc (lacc, norm_offset, rchild->size,
2235 rchild->grp_hint = 1;
2236 new_acc->grp_hint |= new_acc->grp_read;
2237 if (rchild->first_child)
2238 ret |= propagate_subaccesses_across_link (new_acc, rchild);
2243 rchild->grp_hint = 1;
2244 new_acc = create_artificial_child_access (lacc, rchild, norm_offset);
2248 if (racc->first_child)
2249 propagate_subaccesses_across_link (new_acc, rchild);
2256 /* Propagate all subaccesses across assignment links. */
2259 propagate_all_subaccesses (void)
2261 while (work_queue_head)
2263 struct access *racc = pop_access_from_work_queue ();
2264 struct assign_link *link;
2266 gcc_assert (racc->first_link);
2268 for (link = racc->first_link; link; link = link->next)
2270 struct access *lacc = link->lacc;
2272 if (!bitmap_bit_p (candidate_bitmap, DECL_UID (lacc->base)))
2274 lacc = lacc->group_representative;
2275 if (propagate_subaccesses_across_link (lacc, racc)
2276 && lacc->first_link)
2277 add_access_to_work_queue (lacc);
2282 /* Go through all accesses collected throughout the (intraprocedural) analysis
2283 stage, exclude overlapping ones, identify representatives and build trees
2284 out of them, making decisions about scalarization on the way. Return true
2285 iff there are any to-be-scalarized variables after this stage. */
2288 analyze_all_variable_accesses (void)
2291 bitmap tmp = BITMAP_ALLOC (NULL);
2293 unsigned i, max_total_scalarization_size;
2295 max_total_scalarization_size = UNITS_PER_WORD * BITS_PER_UNIT
2296 * MOVE_RATIO (optimize_function_for_speed_p (cfun));
2298 EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
2299 if (bitmap_bit_p (should_scalarize_away_bitmap, i)
2300 && !bitmap_bit_p (cannot_scalarize_away_bitmap, i))
2302 tree var = referenced_var (i);
2304 if (TREE_CODE (var) == VAR_DECL
2305 && ((unsigned) tree_low_cst (TYPE_SIZE (TREE_TYPE (var)), 1)
2306 <= max_total_scalarization_size)
2307 && type_consists_of_records_p (TREE_TYPE (var)))
2309 completely_scalarize_record (var, var, 0, var);
2310 if (dump_file && (dump_flags & TDF_DETAILS))
2312 fprintf (dump_file, "Will attempt to totally scalarize ");
2313 print_generic_expr (dump_file, var, 0);
2314 fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2319 bitmap_copy (tmp, candidate_bitmap);
2320 EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2322 tree var = referenced_var (i);
2323 struct access *access;
2325 access = sort_and_splice_var_accesses (var);
2326 if (!access || !build_access_trees (access))
2327 disqualify_candidate (var,
2328 "No or inhibitingly overlapping accesses.");
2331 propagate_all_subaccesses ();
2333 bitmap_copy (tmp, candidate_bitmap);
2334 EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2336 tree var = referenced_var (i);
2337 struct access *access = get_first_repr_for_decl (var);
2339 if (analyze_access_trees (access))
2342 if (dump_file && (dump_flags & TDF_DETAILS))
2344 fprintf (dump_file, "\nAccess trees for ");
2345 print_generic_expr (dump_file, var, 0);
2346 fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2347 dump_access_tree (dump_file, access);
2348 fprintf (dump_file, "\n");
2352 disqualify_candidate (var, "No scalar replacements to be created.");
2359 statistics_counter_event (cfun, "Scalarized aggregates", res);
2366 /* Generate statements copying scalar replacements of accesses within a subtree
2367 into or out of AGG. ACCESS, all its children, siblings and their children
2368 are to be processed. AGG is an aggregate type expression (can be a
2369 declaration but does not have to be, it can for example also be a mem_ref or
2370 a series of handled components). TOP_OFFSET is the offset of the processed
2371 subtree which has to be subtracted from offsets of individual accesses to
2372 get corresponding offsets for AGG. If CHUNK_SIZE is non-null, copy only
2373 replacements in the interval <start_offset, start_offset + chunk_size>,
2374 otherwise copy all. GSI is a statement iterator used to place the new
2375 statements. WRITE should be true when the statements should write from AGG
2376 to the replacement and false if vice versa. if INSERT_AFTER is true, new
2377 statements will be added after the current statement in GSI, they will be
2378 added before the statement otherwise. */
2381 generate_subtree_copies (struct access *access, tree agg,
2382 HOST_WIDE_INT top_offset,
2383 HOST_WIDE_INT start_offset, HOST_WIDE_INT chunk_size,
2384 gimple_stmt_iterator *gsi, bool write,
2385 bool insert_after, location_t loc)
2389 if (chunk_size && access->offset >= start_offset + chunk_size)
2392 if (access->grp_to_be_replaced
2394 || access->offset + access->size > start_offset))
2396 tree expr, repl = get_access_replacement (access);
2399 expr = build_ref_for_model (loc, agg, access->offset - top_offset,
2400 access, gsi, insert_after);
2404 if (access->grp_partial_lhs)
2405 expr = force_gimple_operand_gsi (gsi, expr, true, NULL_TREE,
2407 insert_after ? GSI_NEW_STMT
2409 stmt = gimple_build_assign (repl, expr);
2413 TREE_NO_WARNING (repl) = 1;
2414 if (access->grp_partial_lhs)
2415 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
2417 insert_after ? GSI_NEW_STMT
2419 stmt = gimple_build_assign (expr, repl);
2421 gimple_set_location (stmt, loc);
2424 gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2426 gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2428 sra_stats.subtree_copies++;
2431 if (access->first_child)
2432 generate_subtree_copies (access->first_child, agg, top_offset,
2433 start_offset, chunk_size, gsi,
2434 write, insert_after, loc);
2436 access = access->next_sibling;
2441 /* Assign zero to all scalar replacements in an access subtree. ACCESS is the
2442 the root of the subtree to be processed. GSI is the statement iterator used
2443 for inserting statements which are added after the current statement if
2444 INSERT_AFTER is true or before it otherwise. */
2447 init_subtree_with_zero (struct access *access, gimple_stmt_iterator *gsi,
2448 bool insert_after, location_t loc)
2451 struct access *child;
2453 if (access->grp_to_be_replaced)
2457 stmt = gimple_build_assign (get_access_replacement (access),
2458 build_zero_cst (access->type));
2460 gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2462 gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2464 gimple_set_location (stmt, loc);
2467 for (child = access->first_child; child; child = child->next_sibling)
2468 init_subtree_with_zero (child, gsi, insert_after, loc);
2471 /* Search for an access representative for the given expression EXPR and
2472 return it or NULL if it cannot be found. */
2474 static struct access *
2475 get_access_for_expr (tree expr)
2477 HOST_WIDE_INT offset, size, max_size;
2480 /* FIXME: This should not be necessary but Ada produces V_C_Es with a type of
2481 a different size than the size of its argument and we need the latter
2483 if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
2484 expr = TREE_OPERAND (expr, 0);
2486 base = get_ref_base_and_extent (expr, &offset, &size, &max_size);
2487 if (max_size == -1 || !DECL_P (base))
2490 if (!bitmap_bit_p (candidate_bitmap, DECL_UID (base)))
2493 return get_var_base_offset_size_access (base, offset, max_size);
2496 /* Replace the expression EXPR with a scalar replacement if there is one and
2497 generate other statements to do type conversion or subtree copying if
2498 necessary. GSI is used to place newly created statements, WRITE is true if
2499 the expression is being written to (it is on a LHS of a statement or output
2500 in an assembly statement). */
2503 sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi, bool write)
2506 struct access *access;
2509 if (TREE_CODE (*expr) == BIT_FIELD_REF)
2512 expr = &TREE_OPERAND (*expr, 0);
2517 if (TREE_CODE (*expr) == REALPART_EXPR || TREE_CODE (*expr) == IMAGPART_EXPR)
2518 expr = &TREE_OPERAND (*expr, 0);
2519 access = get_access_for_expr (*expr);
2522 type = TREE_TYPE (*expr);
2524 loc = gimple_location (gsi_stmt (*gsi));
2525 if (access->grp_to_be_replaced)
2527 tree repl = get_access_replacement (access);
2528 /* If we replace a non-register typed access simply use the original
2529 access expression to extract the scalar component afterwards.
2530 This happens if scalarizing a function return value or parameter
2531 like in gcc.c-torture/execute/20041124-1.c, 20050316-1.c and
2532 gcc.c-torture/compile/20011217-1.c.
2534 We also want to use this when accessing a complex or vector which can
2535 be accessed as a different type too, potentially creating a need for
2536 type conversion (see PR42196) and when scalarized unions are involved
2537 in assembler statements (see PR42398). */
2538 if (!useless_type_conversion_p (type, access->type))
2542 ref = build_ref_for_model (loc, access->base, access->offset, access,
2549 if (access->grp_partial_lhs)
2550 ref = force_gimple_operand_gsi (gsi, ref, true, NULL_TREE,
2551 false, GSI_NEW_STMT);
2552 stmt = gimple_build_assign (repl, ref);
2553 gimple_set_location (stmt, loc);
2554 gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2560 if (access->grp_partial_lhs)
2561 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
2562 true, GSI_SAME_STMT);
2563 stmt = gimple_build_assign (ref, repl);
2564 gimple_set_location (stmt, loc);
2565 gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2573 if (access->first_child)
2575 HOST_WIDE_INT start_offset, chunk_size;
2577 && host_integerp (TREE_OPERAND (bfr, 1), 1)
2578 && host_integerp (TREE_OPERAND (bfr, 2), 1))
2580 chunk_size = tree_low_cst (TREE_OPERAND (bfr, 1), 1);
2581 start_offset = access->offset
2582 + tree_low_cst (TREE_OPERAND (bfr, 2), 1);
2585 start_offset = chunk_size = 0;
2587 generate_subtree_copies (access->first_child, access->base, 0,
2588 start_offset, chunk_size, gsi, write, write,
2594 /* Where scalar replacements of the RHS have been written to when a replacement
2595 of a LHS of an assigments cannot be direclty loaded from a replacement of
2597 enum unscalarized_data_handling { SRA_UDH_NONE, /* Nothing done so far. */
2598 SRA_UDH_RIGHT, /* Data flushed to the RHS. */
2599 SRA_UDH_LEFT }; /* Data flushed to the LHS. */
2601 /* Store all replacements in the access tree rooted in TOP_RACC either to their
2602 base aggregate if there are unscalarized data or directly to LHS of the
2603 statement that is pointed to by GSI otherwise. */
2605 static enum unscalarized_data_handling
2606 handle_unscalarized_data_in_subtree (struct access *top_racc,
2607 gimple_stmt_iterator *gsi)
2609 if (top_racc->grp_unscalarized_data)
2611 generate_subtree_copies (top_racc->first_child, top_racc->base, 0, 0, 0,
2613 gimple_location (gsi_stmt (*gsi)));
2614 return SRA_UDH_RIGHT;
2618 tree lhs = gimple_assign_lhs (gsi_stmt (*gsi));
2619 generate_subtree_copies (top_racc->first_child, lhs, top_racc->offset,
2620 0, 0, gsi, false, false,
2621 gimple_location (gsi_stmt (*gsi)));
2622 return SRA_UDH_LEFT;
2627 /* Try to generate statements to load all sub-replacements in an access subtree
2628 formed by children of LACC from scalar replacements in the TOP_RACC subtree.
2629 If that is not possible, refresh the TOP_RACC base aggregate and load the
2630 accesses from it. LEFT_OFFSET is the offset of the left whole subtree being
2631 copied. NEW_GSI is stmt iterator used for statement insertions after the
2632 original assignment, OLD_GSI is used to insert statements before the
2633 assignment. *REFRESHED keeps the information whether we have needed to
2634 refresh replacements of the LHS and from which side of the assignments this
2638 load_assign_lhs_subreplacements (struct access *lacc, struct access *top_racc,
2639 HOST_WIDE_INT left_offset,
2640 gimple_stmt_iterator *old_gsi,
2641 gimple_stmt_iterator *new_gsi,
2642 enum unscalarized_data_handling *refreshed)
2644 location_t loc = gimple_location (gsi_stmt (*old_gsi));
2645 for (lacc = lacc->first_child; lacc; lacc = lacc->next_sibling)
2647 if (lacc->grp_to_be_replaced)
2649 struct access *racc;
2650 HOST_WIDE_INT offset = lacc->offset - left_offset + top_racc->offset;
2654 racc = find_access_in_subtree (top_racc, offset, lacc->size);
2655 if (racc && racc->grp_to_be_replaced)
2657 rhs = get_access_replacement (racc);
2658 if (!useless_type_conversion_p (lacc->type, racc->type))
2659 rhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR, lacc->type, rhs);
2661 if (racc->grp_partial_lhs && lacc->grp_partial_lhs)
2662 rhs = force_gimple_operand_gsi (old_gsi, rhs, true, NULL_TREE,
2663 true, GSI_SAME_STMT);
2667 /* No suitable access on the right hand side, need to load from
2668 the aggregate. See if we have to update it first... */
2669 if (*refreshed == SRA_UDH_NONE)
2670 *refreshed = handle_unscalarized_data_in_subtree (top_racc,
2673 if (*refreshed == SRA_UDH_LEFT)
2674 rhs = build_ref_for_model (loc, lacc->base, lacc->offset, lacc,
2677 rhs = build_ref_for_model (loc, top_racc->base, offset, lacc,
2679 if (lacc->grp_partial_lhs)
2680 rhs = force_gimple_operand_gsi (new_gsi, rhs, true, NULL_TREE,
2681 false, GSI_NEW_STMT);
2684 stmt = gimple_build_assign (get_access_replacement (lacc), rhs);
2685 gsi_insert_after (new_gsi, stmt, GSI_NEW_STMT);
2686 gimple_set_location (stmt, loc);
2688 sra_stats.subreplacements++;
2690 else if (*refreshed == SRA_UDH_NONE
2691 && lacc->grp_read && !lacc->grp_covered)
2692 *refreshed = handle_unscalarized_data_in_subtree (top_racc,
2695 if (lacc->first_child)
2696 load_assign_lhs_subreplacements (lacc, top_racc, left_offset,
2697 old_gsi, new_gsi, refreshed);
2701 /* Result code for SRA assignment modification. */
2702 enum assignment_mod_result { SRA_AM_NONE, /* nothing done for the stmt */
2703 SRA_AM_MODIFIED, /* stmt changed but not
2705 SRA_AM_REMOVED }; /* stmt eliminated */
2707 /* Modify assignments with a CONSTRUCTOR on their RHS. STMT contains a pointer
2708 to the assignment and GSI is the statement iterator pointing at it. Returns
2709 the same values as sra_modify_assign. */
2711 static enum assignment_mod_result
2712 sra_modify_constructor_assign (gimple *stmt, gimple_stmt_iterator *gsi)
2714 tree lhs = gimple_assign_lhs (*stmt);
2718 acc = get_access_for_expr (lhs);
2722 loc = gimple_location (*stmt);
2723 if (VEC_length (constructor_elt,
2724 CONSTRUCTOR_ELTS (gimple_assign_rhs1 (*stmt))) > 0)
2726 /* I have never seen this code path trigger but if it can happen the
2727 following should handle it gracefully. */
2728 if (access_has_children_p (acc))
2729 generate_subtree_copies (acc->first_child, acc->base, 0, 0, 0, gsi,
2731 return SRA_AM_MODIFIED;
2734 if (acc->grp_covered)
2736 init_subtree_with_zero (acc, gsi, false, loc);
2737 unlink_stmt_vdef (*stmt);
2738 gsi_remove (gsi, true);
2739 return SRA_AM_REMOVED;
2743 init_subtree_with_zero (acc, gsi, true, loc);
2744 return SRA_AM_MODIFIED;
2748 /* Create and return a new suitable default definition SSA_NAME for RACC which
2749 is an access describing an uninitialized part of an aggregate that is being
2753 get_repl_default_def_ssa_name (struct access *racc)
2757 decl = get_unrenamed_access_replacement (racc);
2759 repl = gimple_default_def (cfun, decl);
2762 repl = make_ssa_name (decl, gimple_build_nop ());
2763 set_default_def (decl, repl);
2769 /* Return true if REF has a COMPONENT_REF with a bit-field field declaration
2773 contains_bitfld_comp_ref_p (const_tree ref)
2775 while (handled_component_p (ref))
2777 if (TREE_CODE (ref) == COMPONENT_REF
2778 && DECL_BIT_FIELD (TREE_OPERAND (ref, 1)))
2780 ref = TREE_OPERAND (ref, 0);
2786 /* Return true if REF has an VIEW_CONVERT_EXPR or a COMPONENT_REF with a
2787 bit-field field declaration somewhere in it. */
2790 contains_vce_or_bfcref_p (const_tree ref)
2792 while (handled_component_p (ref))
2794 if (TREE_CODE (ref) == VIEW_CONVERT_EXPR
2795 || (TREE_CODE (ref) == COMPONENT_REF
2796 && DECL_BIT_FIELD (TREE_OPERAND (ref, 1))))
2798 ref = TREE_OPERAND (ref, 0);
2804 /* Examine both sides of the assignment statement pointed to by STMT, replace
2805 them with a scalare replacement if there is one and generate copying of
2806 replacements if scalarized aggregates have been used in the assignment. GSI
2807 is used to hold generated statements for type conversions and subtree
2810 static enum assignment_mod_result
2811 sra_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi)
2813 struct access *lacc, *racc;
2815 bool modify_this_stmt = false;
2816 bool force_gimple_rhs = false;
2818 gimple_stmt_iterator orig_gsi = *gsi;
2820 if (!gimple_assign_single_p (*stmt))
2822 lhs = gimple_assign_lhs (*stmt);
2823 rhs = gimple_assign_rhs1 (*stmt);
2825 if (TREE_CODE (rhs) == CONSTRUCTOR)
2826 return sra_modify_constructor_assign (stmt, gsi);
2828 if (TREE_CODE (rhs) == REALPART_EXPR || TREE_CODE (lhs) == REALPART_EXPR
2829 || TREE_CODE (rhs) == IMAGPART_EXPR || TREE_CODE (lhs) == IMAGPART_EXPR
2830 || TREE_CODE (rhs) == BIT_FIELD_REF || TREE_CODE (lhs) == BIT_FIELD_REF)
2832 modify_this_stmt = sra_modify_expr (gimple_assign_rhs1_ptr (*stmt),
2834 modify_this_stmt |= sra_modify_expr (gimple_assign_lhs_ptr (*stmt),
2836 return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
2839 lacc = get_access_for_expr (lhs);
2840 racc = get_access_for_expr (rhs);
2844 loc = gimple_location (*stmt);
2845 if (lacc && lacc->grp_to_be_replaced)
2847 lhs = get_access_replacement (lacc);
2848 gimple_assign_set_lhs (*stmt, lhs);
2849 modify_this_stmt = true;
2850 if (lacc->grp_partial_lhs)
2851 force_gimple_rhs = true;
2855 if (racc && racc->grp_to_be_replaced)
2857 rhs = get_access_replacement (racc);
2858 modify_this_stmt = true;
2859 if (racc->grp_partial_lhs)
2860 force_gimple_rhs = true;
2864 if (modify_this_stmt)
2866 if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
2868 /* If we can avoid creating a VIEW_CONVERT_EXPR do so.
2869 ??? This should move to fold_stmt which we simply should
2870 call after building a VIEW_CONVERT_EXPR here. */
2871 if (AGGREGATE_TYPE_P (TREE_TYPE (lhs))
2872 && !contains_bitfld_comp_ref_p (lhs)
2873 && !access_has_children_p (lacc))
2875 lhs = build_ref_for_model (loc, lhs, 0, racc, gsi, false);
2876 gimple_assign_set_lhs (*stmt, lhs);
2878 else if (AGGREGATE_TYPE_P (TREE_TYPE (rhs))
2879 && !contains_vce_or_bfcref_p (rhs)
2880 && !access_has_children_p (racc))
2881 rhs = build_ref_for_model (loc, rhs, 0, lacc, gsi, false);
2883 if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
2885 rhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR, TREE_TYPE (lhs),
2887 if (is_gimple_reg_type (TREE_TYPE (lhs))
2888 && TREE_CODE (lhs) != SSA_NAME)
2889 force_gimple_rhs = true;
2894 /* From this point on, the function deals with assignments in between
2895 aggregates when at least one has scalar reductions of some of its
2896 components. There are three possible scenarios: Both the LHS and RHS have
2897 to-be-scalarized components, 2) only the RHS has or 3) only the LHS has.
2899 In the first case, we would like to load the LHS components from RHS
2900 components whenever possible. If that is not possible, we would like to
2901 read it directly from the RHS (after updating it by storing in it its own
2902 components). If there are some necessary unscalarized data in the LHS,
2903 those will be loaded by the original assignment too. If neither of these
2904 cases happen, the original statement can be removed. Most of this is done
2905 by load_assign_lhs_subreplacements.
2907 In the second case, we would like to store all RHS scalarized components
2908 directly into LHS and if they cover the aggregate completely, remove the
2909 statement too. In the third case, we want the LHS components to be loaded
2910 directly from the RHS (DSE will remove the original statement if it
2913 This is a bit complex but manageable when types match and when unions do
2914 not cause confusion in a way that we cannot really load a component of LHS
2915 from the RHS or vice versa (the access representing this level can have
2916 subaccesses that are accessible only through a different union field at a
2917 higher level - different from the one used in the examined expression).
2920 Therefore, I specially handle a fourth case, happening when there is a
2921 specific type cast or it is impossible to locate a scalarized subaccess on
2922 the other side of the expression. If that happens, I simply "refresh" the
2923 RHS by storing in it is scalarized components leave the original statement
2924 there to do the copying and then load the scalar replacements of the LHS.
2925 This is what the first branch does. */
2927 if (modify_this_stmt
2928 || gimple_has_volatile_ops (*stmt)
2929 || contains_vce_or_bfcref_p (rhs)
2930 || contains_vce_or_bfcref_p (lhs))
2932 if (access_has_children_p (racc))
2933 generate_subtree_copies (racc->first_child, racc->base, 0, 0, 0,
2934 gsi, false, false, loc);
2935 if (access_has_children_p (lacc))
2936 generate_subtree_copies (lacc->first_child, lacc->base, 0, 0, 0,
2937 gsi, true, true, loc);
2938 sra_stats.separate_lhs_rhs_handling++;
2942 if (access_has_children_p (lacc)
2943 && access_has_children_p (racc)
2944 /* When an access represents an unscalarizable region, it usually
2945 represents accesses with variable offset and thus must not be used
2946 to generate new memory accesses. */
2947 && !lacc->grp_unscalarizable_region
2948 && !racc->grp_unscalarizable_region)
2950 gimple_stmt_iterator orig_gsi = *gsi;
2951 enum unscalarized_data_handling refreshed;
2953 if (lacc->grp_read && !lacc->grp_covered)
2954 refreshed = handle_unscalarized_data_in_subtree (racc, gsi);
2956 refreshed = SRA_UDH_NONE;
2958 load_assign_lhs_subreplacements (lacc, racc, lacc->offset,
2959 &orig_gsi, gsi, &refreshed);
2960 if (refreshed != SRA_UDH_RIGHT)
2963 unlink_stmt_vdef (*stmt);
2964 gsi_remove (&orig_gsi, true);
2965 sra_stats.deleted++;
2966 return SRA_AM_REMOVED;
2973 if (!racc->grp_to_be_replaced && !racc->grp_unscalarized_data)
2977 fprintf (dump_file, "Removing load: ");
2978 print_gimple_stmt (dump_file, *stmt, 0, 0);
2981 if (TREE_CODE (lhs) == SSA_NAME)
2983 rhs = get_repl_default_def_ssa_name (racc);
2984 if (!useless_type_conversion_p (TREE_TYPE (lhs),
2986 rhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR,
2987 TREE_TYPE (lhs), rhs);
2991 if (racc->first_child)
2992 generate_subtree_copies (racc->first_child, lhs,
2993 racc->offset, 0, 0, gsi,
2996 gcc_assert (*stmt == gsi_stmt (*gsi));
2997 unlink_stmt_vdef (*stmt);
2998 gsi_remove (gsi, true);
2999 sra_stats.deleted++;
3000 return SRA_AM_REMOVED;
3003 else if (racc->first_child)
3004 generate_subtree_copies (racc->first_child, lhs, racc->offset,
3005 0, 0, gsi, false, true, loc);
3007 if (access_has_children_p (lacc))
3008 generate_subtree_copies (lacc->first_child, rhs, lacc->offset,
3009 0, 0, gsi, true, true, loc);
3013 /* This gimplification must be done after generate_subtree_copies, lest we
3014 insert the subtree copies in the middle of the gimplified sequence. */
3015 if (force_gimple_rhs)
3016 rhs = force_gimple_operand_gsi (&orig_gsi, rhs, true, NULL_TREE,
3017 true, GSI_SAME_STMT);
3018 if (gimple_assign_rhs1 (*stmt) != rhs)
3020 modify_this_stmt = true;
3021 gimple_assign_set_rhs_from_tree (&orig_gsi, rhs);
3022 gcc_assert (*stmt == gsi_stmt (orig_gsi));
3025 return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
3028 /* Traverse the function body and all modifications as decided in
3029 analyze_all_variable_accesses. Return true iff the CFG has been
3033 sra_modify_function_body (void)
3035 bool cfg_changed = false;
3040 gimple_stmt_iterator gsi = gsi_start_bb (bb);
3041 while (!gsi_end_p (gsi))
3043 gimple stmt = gsi_stmt (gsi);
3044 enum assignment_mod_result assign_result;
3045 bool modified = false, deleted = false;
3049 switch (gimple_code (stmt))
3052 t = gimple_return_retval_ptr (stmt);
3053 if (*t != NULL_TREE)
3054 modified |= sra_modify_expr (t, &gsi, false);
3058 assign_result = sra_modify_assign (&stmt, &gsi);
3059 modified |= assign_result == SRA_AM_MODIFIED;
3060 deleted = assign_result == SRA_AM_REMOVED;
3064 /* Operands must be processed before the lhs. */
3065 for (i = 0; i < gimple_call_num_args (stmt); i++)
3067 t = gimple_call_arg_ptr (stmt, i);
3068 modified |= sra_modify_expr (t, &gsi, false);
3071 if (gimple_call_lhs (stmt))
3073 t = gimple_call_lhs_ptr (stmt);
3074 modified |= sra_modify_expr (t, &gsi, true);
3079 for (i = 0; i < gimple_asm_ninputs (stmt); i++)
3081 t = &TREE_VALUE (gimple_asm_input_op (stmt, i));
3082 modified |= sra_modify_expr (t, &gsi, false);
3084 for (i = 0; i < gimple_asm_noutputs (stmt); i++)
3086 t = &TREE_VALUE (gimple_asm_output_op (stmt, i));
3087 modified |= sra_modify_expr (t, &gsi, true);
3098 if (maybe_clean_eh_stmt (stmt)
3099 && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
3110 /* Generate statements initializing scalar replacements of parts of function
3114 initialize_parameter_reductions (void)
3116 gimple_stmt_iterator gsi;
3117 gimple_seq seq = NULL;
3120 for (parm = DECL_ARGUMENTS (current_function_decl);
3122 parm = DECL_CHAIN (parm))
3124 VEC (access_p, heap) *access_vec;
3125 struct access *access;
3127 if (!bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
3129 access_vec = get_base_access_vector (parm);
3135 seq = gimple_seq_alloc ();
3136 gsi = gsi_start (seq);
3139 for (access = VEC_index (access_p, access_vec, 0);
3141 access = access->next_grp)
3142 generate_subtree_copies (access, parm, 0, 0, 0, &gsi, true, true,
3143 EXPR_LOCATION (parm));
3147 gsi_insert_seq_on_edge_immediate (single_succ_edge (ENTRY_BLOCK_PTR), seq);
3150 /* The "main" function of intraprocedural SRA passes. Runs the analysis and if
3151 it reveals there are components of some aggregates to be scalarized, it runs
3152 the required transformations. */
3154 perform_intra_sra (void)
3159 if (!find_var_candidates ())
3162 if (!scan_function ())
3165 if (!analyze_all_variable_accesses ())
3168 if (sra_modify_function_body ())
3169 ret = TODO_update_ssa | TODO_cleanup_cfg;
3171 ret = TODO_update_ssa;
3172 initialize_parameter_reductions ();
3174 statistics_counter_event (cfun, "Scalar replacements created",
3175 sra_stats.replacements);
3176 statistics_counter_event (cfun, "Modified expressions", sra_stats.exprs);
3177 statistics_counter_event (cfun, "Subtree copy stmts",
3178 sra_stats.subtree_copies);
3179 statistics_counter_event (cfun, "Subreplacement stmts",
3180 sra_stats.subreplacements);
3181 statistics_counter_event (cfun, "Deleted stmts", sra_stats.deleted);
3182 statistics_counter_event (cfun, "Separate LHS and RHS handling",
3183 sra_stats.separate_lhs_rhs_handling);
3186 sra_deinitialize ();
3190 /* Perform early intraprocedural SRA. */
3192 early_intra_sra (void)
3194 sra_mode = SRA_MODE_EARLY_INTRA;
3195 return perform_intra_sra ();
3198 /* Perform "late" intraprocedural SRA. */
3200 late_intra_sra (void)
3202 sra_mode = SRA_MODE_INTRA;
3203 return perform_intra_sra ();
3208 gate_intra_sra (void)
3210 return flag_tree_sra != 0 && dbg_cnt (tree_sra);
3214 struct gimple_opt_pass pass_sra_early =
3219 gate_intra_sra, /* gate */
3220 early_intra_sra, /* execute */
3223 0, /* static_pass_number */
3224 TV_TREE_SRA, /* tv_id */
3225 PROP_cfg | PROP_ssa, /* properties_required */
3226 0, /* properties_provided */
3227 0, /* properties_destroyed */
3228 0, /* todo_flags_start */
3232 | TODO_verify_ssa /* todo_flags_finish */
3236 struct gimple_opt_pass pass_sra =
3241 gate_intra_sra, /* gate */
3242 late_intra_sra, /* execute */
3245 0, /* static_pass_number */
3246 TV_TREE_SRA, /* tv_id */
3247 PROP_cfg | PROP_ssa, /* properties_required */
3248 0, /* properties_provided */
3249 0, /* properties_destroyed */
3250 TODO_update_address_taken, /* todo_flags_start */
3254 | TODO_verify_ssa /* todo_flags_finish */
3259 /* Return true iff PARM (which must be a parm_decl) is an unused scalar
3263 is_unused_scalar_param (tree parm)
3266 return (is_gimple_reg (parm)
3267 && (!(name = gimple_default_def (cfun, parm))
3268 || has_zero_uses (name)));
3271 /* Scan immediate uses of a default definition SSA name of a parameter PARM and
3272 examine whether there are any direct or otherwise infeasible ones. If so,
3273 return true, otherwise return false. PARM must be a gimple register with a
3274 non-NULL default definition. */
3277 ptr_parm_has_direct_uses (tree parm)
3279 imm_use_iterator ui;
3281 tree name = gimple_default_def (cfun, parm);
3284 FOR_EACH_IMM_USE_STMT (stmt, ui, name)
3287 use_operand_p use_p;
3289 if (is_gimple_debug (stmt))
3292 /* Valid uses include dereferences on the lhs and the rhs. */
3293 if (gimple_has_lhs (stmt))
3295 tree lhs = gimple_get_lhs (stmt);
3296 while (handled_component_p (lhs))
3297 lhs = TREE_OPERAND (lhs, 0);
3298 if (TREE_CODE (lhs) == MEM_REF
3299 && TREE_OPERAND (lhs, 0) == name
3300 && integer_zerop (TREE_OPERAND (lhs, 1))
3301 && types_compatible_p (TREE_TYPE (lhs),
3302 TREE_TYPE (TREE_TYPE (name)))
3303 && !TREE_THIS_VOLATILE (lhs))
3306 if (gimple_assign_single_p (stmt))
3308 tree rhs = gimple_assign_rhs1 (stmt);
3309 while (handled_component_p (rhs))
3310 rhs = TREE_OPERAND (rhs, 0);
3311 if (TREE_CODE (rhs) == MEM_REF
3312 && TREE_OPERAND (rhs, 0) == name
3313 && integer_zerop (TREE_OPERAND (rhs, 1))
3314 && types_compatible_p (TREE_TYPE (rhs),
3315 TREE_TYPE (TREE_TYPE (name)))
3316 && !TREE_THIS_VOLATILE (rhs))
3319 else if (is_gimple_call (stmt))
3322 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3324 tree arg = gimple_call_arg (stmt, i);
3325 while (handled_component_p (arg))
3326 arg = TREE_OPERAND (arg, 0);
3327 if (TREE_CODE (arg) == MEM_REF
3328 && TREE_OPERAND (arg, 0) == name
3329 && integer_zerop (TREE_OPERAND (arg, 1))
3330 && types_compatible_p (TREE_TYPE (arg),
3331 TREE_TYPE (TREE_TYPE (name)))
3332 && !TREE_THIS_VOLATILE (arg))
3337 /* If the number of valid uses does not match the number of
3338 uses in this stmt there is an unhandled use. */
3339 FOR_EACH_IMM_USE_ON_STMT (use_p, ui)
3346 BREAK_FROM_IMM_USE_STMT (ui);
3352 /* Identify candidates for reduction for IPA-SRA based on their type and mark
3353 them in candidate_bitmap. Note that these do not necessarily include
3354 parameter which are unused and thus can be removed. Return true iff any
3355 such candidate has been found. */
3358 find_param_candidates (void)
3364 for (parm = DECL_ARGUMENTS (current_function_decl);
3366 parm = DECL_CHAIN (parm))
3368 tree type = TREE_TYPE (parm);
3372 if (TREE_THIS_VOLATILE (parm)
3373 || TREE_ADDRESSABLE (parm)
3374 || (!is_gimple_reg_type (type) && is_va_list_type (type)))
3377 if (is_unused_scalar_param (parm))
3383 if (POINTER_TYPE_P (type))
3385 type = TREE_TYPE (type);
3387 if (TREE_CODE (type) == FUNCTION_TYPE
3388 || TYPE_VOLATILE (type)
3389 || (TREE_CODE (type) == ARRAY_TYPE
3390 && TYPE_NONALIASED_COMPONENT (type))
3391 || !is_gimple_reg (parm)
3392 || is_va_list_type (type)
3393 || ptr_parm_has_direct_uses (parm))
3396 else if (!AGGREGATE_TYPE_P (type))
3399 if (!COMPLETE_TYPE_P (type)
3400 || !host_integerp (TYPE_SIZE (type), 1)
3401 || tree_low_cst (TYPE_SIZE (type), 1) == 0
3402 || (AGGREGATE_TYPE_P (type)
3403 && type_internals_preclude_sra_p (type)))
3406 bitmap_set_bit (candidate_bitmap, DECL_UID (parm));
3408 if (dump_file && (dump_flags & TDF_DETAILS))
3410 fprintf (dump_file, "Candidate (%d): ", DECL_UID (parm));
3411 print_generic_expr (dump_file, parm, 0);
3412 fprintf (dump_file, "\n");
3416 func_param_count = count;
3420 /* Callback of walk_aliased_vdefs, marks the access passed as DATA as
3424 mark_maybe_modified (ao_ref *ao ATTRIBUTE_UNUSED, tree vdef ATTRIBUTE_UNUSED,
3427 struct access *repr = (struct access *) data;
3429 repr->grp_maybe_modified = 1;
3433 /* Analyze what representatives (in linked lists accessible from
3434 REPRESENTATIVES) can be modified by side effects of statements in the
3435 current function. */
3438 analyze_modified_params (VEC (access_p, heap) *representatives)
3442 for (i = 0; i < func_param_count; i++)
3444 struct access *repr;
3446 for (repr = VEC_index (access_p, representatives, i);
3448 repr = repr->next_grp)
3450 struct access *access;
3454 if (no_accesses_p (repr))
3456 if (!POINTER_TYPE_P (TREE_TYPE (repr->base))
3457 || repr->grp_maybe_modified)
3460 ao_ref_init (&ar, repr->expr);
3461 visited = BITMAP_ALLOC (NULL);
3462 for (access = repr; access; access = access->next_sibling)
3464 /* All accesses are read ones, otherwise grp_maybe_modified would
3465 be trivially set. */
3466 walk_aliased_vdefs (&ar, gimple_vuse (access->stmt),
3467 mark_maybe_modified, repr, &visited);
3468 if (repr->grp_maybe_modified)
3471 BITMAP_FREE (visited);
3476 /* Propagate distances in bb_dereferences in the opposite direction than the
3477 control flow edges, in each step storing the maximum of the current value
3478 and the minimum of all successors. These steps are repeated until the table
3479 stabilizes. Note that BBs which might terminate the functions (according to
3480 final_bbs bitmap) never updated in this way. */
3483 propagate_dereference_distances (void)
3485 VEC (basic_block, heap) *queue;
3488 queue = VEC_alloc (basic_block, heap, last_basic_block_for_function (cfun));
3489 VEC_quick_push (basic_block, queue, ENTRY_BLOCK_PTR);
3492 VEC_quick_push (basic_block, queue, bb);
3496 while (!VEC_empty (basic_block, queue))
3500 bool change = false;
3503 bb = VEC_pop (basic_block, queue);
3506 if (bitmap_bit_p (final_bbs, bb->index))
3509 for (i = 0; i < func_param_count; i++)
3511 int idx = bb->index * func_param_count + i;
3513 HOST_WIDE_INT inh = 0;
3515 FOR_EACH_EDGE (e, ei, bb->succs)
3517 int succ_idx = e->dest->index * func_param_count + i;
3519 if (e->src == EXIT_BLOCK_PTR)
3525 inh = bb_dereferences [succ_idx];
3527 else if (bb_dereferences [succ_idx] < inh)
3528 inh = bb_dereferences [succ_idx];
3531 if (!first && bb_dereferences[idx] < inh)
3533 bb_dereferences[idx] = inh;
3538 if (change && !bitmap_bit_p (final_bbs, bb->index))
3539 FOR_EACH_EDGE (e, ei, bb->preds)
3544 e->src->aux = e->src;
3545 VEC_quick_push (basic_block, queue, e->src);
3549 VEC_free (basic_block, heap, queue);
3552 /* Dump a dereferences TABLE with heading STR to file F. */
3555 dump_dereferences_table (FILE *f, const char *str, HOST_WIDE_INT *table)
3559 fprintf (dump_file, str);
3560 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
3562 fprintf (f, "%4i %i ", bb->index, bitmap_bit_p (final_bbs, bb->index));
3563 if (bb != EXIT_BLOCK_PTR)
3566 for (i = 0; i < func_param_count; i++)
3568 int idx = bb->index * func_param_count + i;
3569 fprintf (f, " %4" HOST_WIDE_INT_PRINT "d", table[idx]);
3574 fprintf (dump_file, "\n");
3577 /* Determine what (parts of) parameters passed by reference that are not
3578 assigned to are not certainly dereferenced in this function and thus the
3579 dereferencing cannot be safely moved to the caller without potentially
3580 introducing a segfault. Mark such REPRESENTATIVES as
3581 grp_not_necessarilly_dereferenced.
3583 The dereferenced maximum "distance," i.e. the offset + size of the accessed
3584 part is calculated rather than simple booleans are calculated for each
3585 pointer parameter to handle cases when only a fraction of the whole
3586 aggregate is allocated (see testsuite/gcc.c-torture/execute/ipa-sra-2.c for
3589 The maximum dereference distances for each pointer parameter and BB are
3590 already stored in bb_dereference. This routine simply propagates these
3591 values upwards by propagate_dereference_distances and then compares the
3592 distances of individual parameters in the ENTRY BB to the equivalent
3593 distances of each representative of a (fraction of a) parameter. */
3596 analyze_caller_dereference_legality (VEC (access_p, heap) *representatives)
3600 if (dump_file && (dump_flags & TDF_DETAILS))
3601 dump_dereferences_table (dump_file,
3602 "Dereference table before propagation:\n",
3605 propagate_dereference_distances ();
3607 if (dump_file && (dump_flags & TDF_DETAILS))
3608 dump_dereferences_table (dump_file,
3609 "Dereference table after propagation:\n",
3612 for (i = 0; i < func_param_count; i++)
3614 struct access *repr = VEC_index (access_p, representatives, i);
3615 int idx = ENTRY_BLOCK_PTR->index * func_param_count + i;
3617 if (!repr || no_accesses_p (repr))
3622 if ((repr->offset + repr->size) > bb_dereferences[idx])
3623 repr->grp_not_necessarilly_dereferenced = 1;
3624 repr = repr->next_grp;
3630 /* Return the representative access for the parameter declaration PARM if it is
3631 a scalar passed by reference which is not written to and the pointer value
3632 is not used directly. Thus, if it is legal to dereference it in the caller
3633 and we can rule out modifications through aliases, such parameter should be
3634 turned into one passed by value. Return NULL otherwise. */
3636 static struct access *
3637 unmodified_by_ref_scalar_representative (tree parm)
3639 int i, access_count;
3640 struct access *repr;
3641 VEC (access_p, heap) *access_vec;
3643 access_vec = get_base_access_vector (parm);
3644 gcc_assert (access_vec);
3645 repr = VEC_index (access_p, access_vec, 0);
3648 repr->group_representative = repr;
3650 access_count = VEC_length (access_p, access_vec);
3651 for (i = 1; i < access_count; i++)
3653 struct access *access = VEC_index (access_p, access_vec, i);
3656 access->group_representative = repr;
3657 access->next_sibling = repr->next_sibling;
3658 repr->next_sibling = access;
3662 repr->grp_scalar_ptr = 1;
3666 /* Return true iff this access precludes IPA-SRA of the parameter it is
3670 access_precludes_ipa_sra_p (struct access *access)
3672 /* Avoid issues such as the second simple testcase in PR 42025. The problem
3673 is incompatible assign in a call statement (and possibly even in asm
3674 statements). This can be relaxed by using a new temporary but only for
3675 non-TREE_ADDRESSABLE types and is probably not worth the complexity. (In
3676 intraprocedural SRA we deal with this by keeping the old aggregate around,
3677 something we cannot do in IPA-SRA.) */
3679 && (is_gimple_call (access->stmt)
3680 || gimple_code (access->stmt) == GIMPLE_ASM))
3683 if (STRICT_ALIGNMENT
3684 && tree_non_aligned_mem_p (access->expr, TYPE_ALIGN (access->type)))
3691 /* Sort collected accesses for parameter PARM, identify representatives for
3692 each accessed region and link them together. Return NULL if there are
3693 different but overlapping accesses, return the special ptr value meaning
3694 there are no accesses for this parameter if that is the case and return the
3695 first representative otherwise. Set *RO_GRP if there is a group of accesses
3696 with only read (i.e. no write) accesses. */
3698 static struct access *
3699 splice_param_accesses (tree parm, bool *ro_grp)
3701 int i, j, access_count, group_count;
3702 int agg_size, total_size = 0;
3703 struct access *access, *res, **prev_acc_ptr = &res;
3704 VEC (access_p, heap) *access_vec;
3706 access_vec = get_base_access_vector (parm);
3708 return &no_accesses_representant;
3709 access_count = VEC_length (access_p, access_vec);
3711 VEC_qsort (access_p, access_vec, compare_access_positions);
3716 while (i < access_count)
3720 access = VEC_index (access_p, access_vec, i);
3721 modification = access->write;
3722 if (access_precludes_ipa_sra_p (access))
3724 a1_alias_type = reference_alias_ptr_type (access->expr);
3726 /* Access is about to become group representative unless we find some
3727 nasty overlap which would preclude us from breaking this parameter
3731 while (j < access_count)
3733 struct access *ac2 = VEC_index (access_p, access_vec, j);
3734 if (ac2->offset != access->offset)
3736 /* All or nothing law for parameters. */
3737 if (access->offset + access->size > ac2->offset)
3742 else if (ac2->size != access->size)
3745 if (access_precludes_ipa_sra_p (ac2)
3746 || (ac2->type != access->type
3747 && (TREE_ADDRESSABLE (ac2->type)
3748 || TREE_ADDRESSABLE (access->type)))
3749 || (reference_alias_ptr_type (ac2->expr) != a1_alias_type))
3752 modification |= ac2->write;
3753 ac2->group_representative = access;
3754 ac2->next_sibling = access->next_sibling;
3755 access->next_sibling = ac2;
3760 access->grp_maybe_modified = modification;
3763 *prev_acc_ptr = access;
3764 prev_acc_ptr = &access->next_grp;
3765 total_size += access->size;
3769 if (POINTER_TYPE_P (TREE_TYPE (parm)))
3770 agg_size = tree_low_cst (TYPE_SIZE (TREE_TYPE (TREE_TYPE (parm))), 1);
3772 agg_size = tree_low_cst (TYPE_SIZE (TREE_TYPE (parm)), 1);
3773 if (total_size >= agg_size)
3776 gcc_assert (group_count > 0);
3780 /* Decide whether parameters with representative accesses given by REPR should
3781 be reduced into components. */
3784 decide_one_param_reduction (struct access *repr)
3786 int total_size, cur_parm_size, agg_size, new_param_count, parm_size_limit;
3791 cur_parm_size = tree_low_cst (TYPE_SIZE (TREE_TYPE (parm)), 1);
3792 gcc_assert (cur_parm_size > 0);
3794 if (POINTER_TYPE_P (TREE_TYPE (parm)))
3797 agg_size = tree_low_cst (TYPE_SIZE (TREE_TYPE (TREE_TYPE (parm))), 1);
3802 agg_size = cur_parm_size;
3808 fprintf (dump_file, "Evaluating PARAM group sizes for ");
3809 print_generic_expr (dump_file, parm, 0);
3810 fprintf (dump_file, " (UID: %u): \n", DECL_UID (parm));
3811 for (acc = repr; acc; acc = acc->next_grp)
3812 dump_access (dump_file, acc, true);
3816 new_param_count = 0;
3818 for (; repr; repr = repr->next_grp)
3820 gcc_assert (parm == repr->base);
3822 /* Taking the address of a non-addressable field is verboten. */
3823 if (by_ref && repr->non_addressable)
3826 if (!by_ref || (!repr->grp_maybe_modified
3827 && !repr->grp_not_necessarilly_dereferenced))
3828 total_size += repr->size;
3830 total_size += cur_parm_size;
3835 gcc_assert (new_param_count > 0);
3837 if (optimize_function_for_size_p (cfun))
3838 parm_size_limit = cur_parm_size;
3840 parm_size_limit = (PARAM_VALUE (PARAM_IPA_SRA_PTR_GROWTH_FACTOR)
3843 if (total_size < agg_size
3844 && total_size <= parm_size_limit)
3847 fprintf (dump_file, " ....will be split into %i components\n",
3849 return new_param_count;
3855 /* The order of the following enums is important, we need to do extra work for
3856 UNUSED_PARAMS, BY_VAL_ACCESSES and UNMODIF_BY_REF_ACCESSES. */
3857 enum ipa_splicing_result { NO_GOOD_ACCESS, UNUSED_PARAMS, BY_VAL_ACCESSES,
3858 MODIF_BY_REF_ACCESSES, UNMODIF_BY_REF_ACCESSES };
3860 /* Identify representatives of all accesses to all candidate parameters for
3861 IPA-SRA. Return result based on what representatives have been found. */
3863 static enum ipa_splicing_result
3864 splice_all_param_accesses (VEC (access_p, heap) **representatives)
3866 enum ipa_splicing_result result = NO_GOOD_ACCESS;
3868 struct access *repr;
3870 *representatives = VEC_alloc (access_p, heap, func_param_count);
3872 for (parm = DECL_ARGUMENTS (current_function_decl);
3874 parm = DECL_CHAIN (parm))
3876 if (is_unused_scalar_param (parm))
3878 VEC_quick_push (access_p, *representatives,
3879 &no_accesses_representant);
3880 if (result == NO_GOOD_ACCESS)
3881 result = UNUSED_PARAMS;
3883 else if (POINTER_TYPE_P (TREE_TYPE (parm))
3884 && is_gimple_reg_type (TREE_TYPE (TREE_TYPE (parm)))
3885 && bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
3887 repr = unmodified_by_ref_scalar_representative (parm);
3888 VEC_quick_push (access_p, *representatives, repr);
3890 result = UNMODIF_BY_REF_ACCESSES;
3892 else if (bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
3894 bool ro_grp = false;
3895 repr = splice_param_accesses (parm, &ro_grp);
3896 VEC_quick_push (access_p, *representatives, repr);
3898 if (repr && !no_accesses_p (repr))
3900 if (POINTER_TYPE_P (TREE_TYPE (parm)))
3903 result = UNMODIF_BY_REF_ACCESSES;
3904 else if (result < MODIF_BY_REF_ACCESSES)
3905 result = MODIF_BY_REF_ACCESSES;
3907 else if (result < BY_VAL_ACCESSES)
3908 result = BY_VAL_ACCESSES;
3910 else if (no_accesses_p (repr) && (result == NO_GOOD_ACCESS))
3911 result = UNUSED_PARAMS;
3914 VEC_quick_push (access_p, *representatives, NULL);
3917 if (result == NO_GOOD_ACCESS)
3919 VEC_free (access_p, heap, *representatives);
3920 *representatives = NULL;
3921 return NO_GOOD_ACCESS;
3927 /* Return the index of BASE in PARMS. Abort if it is not found. */
3930 get_param_index (tree base, VEC(tree, heap) *parms)
3934 len = VEC_length (tree, parms);
3935 for (i = 0; i < len; i++)
3936 if (VEC_index (tree, parms, i) == base)
3941 /* Convert the decisions made at the representative level into compact
3942 parameter adjustments. REPRESENTATIVES are pointers to first
3943 representatives of each param accesses, ADJUSTMENTS_COUNT is the expected
3944 final number of adjustments. */
3946 static ipa_parm_adjustment_vec
3947 turn_representatives_into_adjustments (VEC (access_p, heap) *representatives,
3948 int adjustments_count)
3950 VEC (tree, heap) *parms;
3951 ipa_parm_adjustment_vec adjustments;
3955 gcc_assert (adjustments_count > 0);
3956 parms = ipa_get_vector_of_formal_parms (current_function_decl);
3957 adjustments = VEC_alloc (ipa_parm_adjustment_t, heap, adjustments_count);
3958 parm = DECL_ARGUMENTS (current_function_decl);
3959 for (i = 0; i < func_param_count; i++, parm = DECL_CHAIN (parm))
3961 struct access *repr = VEC_index (access_p, representatives, i);
3963 if (!repr || no_accesses_p (repr))
3965 struct ipa_parm_adjustment *adj;
3967 adj = VEC_quick_push (ipa_parm_adjustment_t, adjustments, NULL);
3968 memset (adj, 0, sizeof (*adj));
3969 adj->base_index = get_param_index (parm, parms);
3972 adj->copy_param = 1;
3974 adj->remove_param = 1;
3978 struct ipa_parm_adjustment *adj;
3979 int index = get_param_index (parm, parms);
3981 for (; repr; repr = repr->next_grp)
3983 adj = VEC_quick_push (ipa_parm_adjustment_t, adjustments, NULL);
3984 memset (adj, 0, sizeof (*adj));
3985 gcc_assert (repr->base == parm);
3986 adj->base_index = index;
3987 adj->base = repr->base;
3988 adj->type = repr->type;
3989 adj->alias_ptr_type = reference_alias_ptr_type (repr->expr);
3990 adj->offset = repr->offset;
3991 adj->by_ref = (POINTER_TYPE_P (TREE_TYPE (repr->base))
3992 && (repr->grp_maybe_modified
3993 || repr->grp_not_necessarilly_dereferenced));
3998 VEC_free (tree, heap, parms);
4002 /* Analyze the collected accesses and produce a plan what to do with the
4003 parameters in the form of adjustments, NULL meaning nothing. */
4005 static ipa_parm_adjustment_vec
4006 analyze_all_param_acesses (void)
4008 enum ipa_splicing_result repr_state;
4009 bool proceed = false;
4010 int i, adjustments_count = 0;
4011 VEC (access_p, heap) *representatives;
4012 ipa_parm_adjustment_vec adjustments;
4014 repr_state = splice_all_param_accesses (&representatives);
4015 if (repr_state == NO_GOOD_ACCESS)
4018 /* If there are any parameters passed by reference which are not modified
4019 directly, we need to check whether they can be modified indirectly. */
4020 if (repr_state == UNMODIF_BY_REF_ACCESSES)
4022 analyze_caller_dereference_legality (representatives);
4023 analyze_modified_params (representatives);
4026 for (i = 0; i < func_param_count; i++)
4028 struct access *repr = VEC_index (access_p, representatives, i);
4030 if (repr && !no_accesses_p (repr))
4032 if (repr->grp_scalar_ptr)
4034 adjustments_count++;
4035 if (repr->grp_not_necessarilly_dereferenced
4036 || repr->grp_maybe_modified)
4037 VEC_replace (access_p, representatives, i, NULL);
4041 sra_stats.scalar_by_ref_to_by_val++;
4046 int new_components = decide_one_param_reduction (repr);
4048 if (new_components == 0)
4050 VEC_replace (access_p, representatives, i, NULL);
4051 adjustments_count++;
4055 adjustments_count += new_components;
4056 sra_stats.aggregate_params_reduced++;
4057 sra_stats.param_reductions_created += new_components;
4064 if (no_accesses_p (repr))
4067 sra_stats.deleted_unused_parameters++;
4069 adjustments_count++;
4073 if (!proceed && dump_file)
4074 fprintf (dump_file, "NOT proceeding to change params.\n");
4077 adjustments = turn_representatives_into_adjustments (representatives,
4082 VEC_free (access_p, heap, representatives);
4086 /* If a parameter replacement identified by ADJ does not yet exist in the form
4087 of declaration, create it and record it, otherwise return the previously
4091 get_replaced_param_substitute (struct ipa_parm_adjustment *adj)
4094 if (!adj->new_ssa_base)
4096 char *pretty_name = make_fancy_name (adj->base);
4098 repl = create_tmp_reg (TREE_TYPE (adj->base), "ISR");
4099 DECL_NAME (repl) = get_identifier (pretty_name);
4100 obstack_free (&name_obstack, pretty_name);
4103 add_referenced_var (repl);
4104 adj->new_ssa_base = repl;
4107 repl = adj->new_ssa_base;
4111 /* Find the first adjustment for a particular parameter BASE in a vector of
4112 ADJUSTMENTS which is not a copy_param. Return NULL if there is no such
4115 static struct ipa_parm_adjustment *
4116 get_adjustment_for_base (ipa_parm_adjustment_vec adjustments, tree base)
4120 len = VEC_length (ipa_parm_adjustment_t, adjustments);
4121 for (i = 0; i < len; i++)
4123 struct ipa_parm_adjustment *adj;
4125 adj = VEC_index (ipa_parm_adjustment_t, adjustments, i);
4126 if (!adj->copy_param && adj->base == base)
4133 /* If the statement STMT defines an SSA_NAME of a parameter which is to be
4134 removed because its value is not used, replace the SSA_NAME with a one
4135 relating to a created VAR_DECL together all of its uses and return true.
4136 ADJUSTMENTS is a pointer to an adjustments vector. */
4139 replace_removed_params_ssa_names (gimple stmt,
4140 ipa_parm_adjustment_vec adjustments)
4142 struct ipa_parm_adjustment *adj;
4143 tree lhs, decl, repl, name;
4145 if (gimple_code (stmt) == GIMPLE_PHI)
4146 lhs = gimple_phi_result (stmt);
4147 else if (is_gimple_assign (stmt))
4148 lhs = gimple_assign_lhs (stmt);
4149 else if (is_gimple_call (stmt))
4150 lhs = gimple_call_lhs (stmt);
4154 if (TREE_CODE (lhs) != SSA_NAME)
4156 decl = SSA_NAME_VAR (lhs);
4157 if (TREE_CODE (decl) != PARM_DECL)
4160 adj = get_adjustment_for_base (adjustments, decl);
4164 repl = get_replaced_param_substitute (adj);
4165 name = make_ssa_name (repl, stmt);
4169 fprintf (dump_file, "replacing an SSA name of a removed param ");
4170 print_generic_expr (dump_file, lhs, 0);
4171 fprintf (dump_file, " with ");
4172 print_generic_expr (dump_file, name, 0);
4173 fprintf (dump_file, "\n");
4176 if (is_gimple_assign (stmt))
4177 gimple_assign_set_lhs (stmt, name);
4178 else if (is_gimple_call (stmt))
4179 gimple_call_set_lhs (stmt, name);
4181 gimple_phi_set_result (stmt, name);
4183 replace_uses_by (lhs, name);
4184 release_ssa_name (lhs);
4188 /* If the expression *EXPR should be replaced by a reduction of a parameter, do
4189 so. ADJUSTMENTS is a pointer to a vector of adjustments. CONVERT
4190 specifies whether the function should care about type incompatibility the
4191 current and new expressions. If it is false, the function will leave
4192 incompatibility issues to the caller. Return true iff the expression
4196 sra_ipa_modify_expr (tree *expr, bool convert,
4197 ipa_parm_adjustment_vec adjustments)
4200 struct ipa_parm_adjustment *adj, *cand = NULL;
4201 HOST_WIDE_INT offset, size, max_size;
4204 len = VEC_length (ipa_parm_adjustment_t, adjustments);
4206 if (TREE_CODE (*expr) == BIT_FIELD_REF
4207 || TREE_CODE (*expr) == IMAGPART_EXPR
4208 || TREE_CODE (*expr) == REALPART_EXPR)
4210 expr = &TREE_OPERAND (*expr, 0);
4214 base = get_ref_base_and_extent (*expr, &offset, &size, &max_size);
4215 if (!base || size == -1 || max_size == -1)
4218 if (TREE_CODE (base) == MEM_REF)
4220 offset += mem_ref_offset (base).low * BITS_PER_UNIT;
4221 base = TREE_OPERAND (base, 0);
4224 base = get_ssa_base_param (base);
4225 if (!base || TREE_CODE (base) != PARM_DECL)
4228 for (i = 0; i < len; i++)
4230 adj = VEC_index (ipa_parm_adjustment_t, adjustments, i);
4232 if (adj->base == base &&
4233 (adj->offset == offset || adj->remove_param))
4239 if (!cand || cand->copy_param || cand->remove_param)
4243 src = build_simple_mem_ref (cand->reduction);
4245 src = cand->reduction;
4247 if (dump_file && (dump_flags & TDF_DETAILS))
4249 fprintf (dump_file, "About to replace expr ");
4250 print_generic_expr (dump_file, *expr, 0);
4251 fprintf (dump_file, " with ");
4252 print_generic_expr (dump_file, src, 0);
4253 fprintf (dump_file, "\n");
4256 if (convert && !useless_type_conversion_p (TREE_TYPE (*expr), cand->type))
4258 tree vce = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (*expr), src);
4266 /* If the statement pointed to by STMT_PTR contains any expressions that need
4267 to replaced with a different one as noted by ADJUSTMENTS, do so. Handle any
4268 potential type incompatibilities (GSI is used to accommodate conversion
4269 statements and must point to the statement). Return true iff the statement
4273 sra_ipa_modify_assign (gimple *stmt_ptr, gimple_stmt_iterator *gsi,
4274 ipa_parm_adjustment_vec adjustments)
4276 gimple stmt = *stmt_ptr;
4277 tree *lhs_p, *rhs_p;
4280 if (!gimple_assign_single_p (stmt))
4283 rhs_p = gimple_assign_rhs1_ptr (stmt);
4284 lhs_p = gimple_assign_lhs_ptr (stmt);
4286 any = sra_ipa_modify_expr (rhs_p, false, adjustments);
4287 any |= sra_ipa_modify_expr (lhs_p, false, adjustments);
4290 tree new_rhs = NULL_TREE;
4292 if (!useless_type_conversion_p (TREE_TYPE (*lhs_p), TREE_TYPE (*rhs_p)))
4294 if (TREE_CODE (*rhs_p) == CONSTRUCTOR)
4296 /* V_C_Es of constructors can cause trouble (PR 42714). */
4297 if (is_gimple_reg_type (TREE_TYPE (*lhs_p)))
4298 *rhs_p = build_zero_cst (TREE_TYPE (*lhs_p));
4300 *rhs_p = build_constructor (TREE_TYPE (*lhs_p), 0);
4303 new_rhs = fold_build1_loc (gimple_location (stmt),
4304 VIEW_CONVERT_EXPR, TREE_TYPE (*lhs_p),
4307 else if (REFERENCE_CLASS_P (*rhs_p)
4308 && is_gimple_reg_type (TREE_TYPE (*lhs_p))
4309 && !is_gimple_reg (*lhs_p))
4310 /* This can happen when an assignment in between two single field
4311 structures is turned into an assignment in between two pointers to
4312 scalars (PR 42237). */
4317 tree tmp = force_gimple_operand_gsi (gsi, new_rhs, true, NULL_TREE,
4318 true, GSI_SAME_STMT);
4320 gimple_assign_set_rhs_from_tree (gsi, tmp);
4329 /* Traverse the function body and all modifications as described in
4330 ADJUSTMENTS. Return true iff the CFG has been changed. */
4333 ipa_sra_modify_function_body (ipa_parm_adjustment_vec adjustments)
4335 bool cfg_changed = false;
4340 gimple_stmt_iterator gsi;
4342 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
4343 replace_removed_params_ssa_names (gsi_stmt (gsi), adjustments);
4345 gsi = gsi_start_bb (bb);
4346 while (!gsi_end_p (gsi))
4348 gimple stmt = gsi_stmt (gsi);
4349 bool modified = false;
4353 switch (gimple_code (stmt))
4356 t = gimple_return_retval_ptr (stmt);
4357 if (*t != NULL_TREE)
4358 modified |= sra_ipa_modify_expr (t, true, adjustments);
4362 modified |= sra_ipa_modify_assign (&stmt, &gsi, adjustments);
4363 modified |= replace_removed_params_ssa_names (stmt, adjustments);
4367 /* Operands must be processed before the lhs. */
4368 for (i = 0; i < gimple_call_num_args (stmt); i++)
4370 t = gimple_call_arg_ptr (stmt, i);
4371 modified |= sra_ipa_modify_expr (t, true, adjustments);
4374 if (gimple_call_lhs (stmt))
4376 t = gimple_call_lhs_ptr (stmt);
4377 modified |= sra_ipa_modify_expr (t, false, adjustments);
4378 modified |= replace_removed_params_ssa_names (stmt,
4384 for (i = 0; i < gimple_asm_ninputs (stmt); i++)
4386 t = &TREE_VALUE (gimple_asm_input_op (stmt, i));
4387 modified |= sra_ipa_modify_expr (t, true, adjustments);
4389 for (i = 0; i < gimple_asm_noutputs (stmt); i++)
4391 t = &TREE_VALUE (gimple_asm_output_op (stmt, i));
4392 modified |= sra_ipa_modify_expr (t, false, adjustments);
4403 if (maybe_clean_eh_stmt (stmt)
4404 && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
4414 /* Call gimple_debug_bind_reset_value on all debug statements describing
4415 gimple register parameters that are being removed or replaced. */
4418 sra_ipa_reset_debug_stmts (ipa_parm_adjustment_vec adjustments)
4422 len = VEC_length (ipa_parm_adjustment_t, adjustments);
4423 for (i = 0; i < len; i++)
4425 struct ipa_parm_adjustment *adj;
4426 imm_use_iterator ui;
4430 adj = VEC_index (ipa_parm_adjustment_t, adjustments, i);
4431 if (adj->copy_param || !is_gimple_reg (adj->base))
4433 name = gimple_default_def (cfun, adj->base);
4436 FOR_EACH_IMM_USE_STMT (stmt, ui, name)
4438 /* All other users must have been removed by
4439 ipa_sra_modify_function_body. */
4440 gcc_assert (is_gimple_debug (stmt));
4441 gimple_debug_bind_reset_value (stmt);
4447 /* Return true iff all callers have at least as many actual arguments as there
4448 are formal parameters in the current function. */
4451 all_callers_have_enough_arguments_p (struct cgraph_node *node)
4453 struct cgraph_edge *cs;
4454 for (cs = node->callers; cs; cs = cs->next_caller)
4455 if (!callsite_has_enough_arguments_p (cs->call_stmt))
4462 /* Convert all callers of NODE to pass parameters as given in ADJUSTMENTS. */
4465 convert_callers (struct cgraph_node *node, tree old_decl,
4466 ipa_parm_adjustment_vec adjustments)
4468 tree old_cur_fndecl = current_function_decl;
4469 struct cgraph_edge *cs;
4470 basic_block this_block;
4471 bitmap recomputed_callers = BITMAP_ALLOC (NULL);
4473 for (cs = node->callers; cs; cs = cs->next_caller)
4475 current_function_decl = cs->caller->decl;
4476 push_cfun (DECL_STRUCT_FUNCTION (cs->caller->decl));
4479 fprintf (dump_file, "Adjusting call (%i -> %i) %s -> %s\n",
4480 cs->caller->uid, cs->callee->uid,
4481 cgraph_node_name (cs->caller),
4482 cgraph_node_name (cs->callee));
4484 ipa_modify_call_arguments (cs, cs->call_stmt, adjustments);
4489 for (cs = node->callers; cs; cs = cs->next_caller)
4490 if (bitmap_set_bit (recomputed_callers, cs->caller->uid)
4491 && gimple_in_ssa_p (DECL_STRUCT_FUNCTION (cs->caller->decl)))
4492 compute_inline_parameters (cs->caller);
4493 BITMAP_FREE (recomputed_callers);
4495 current_function_decl = old_cur_fndecl;
4497 if (!encountered_recursive_call)
4500 FOR_EACH_BB (this_block)
4502 gimple_stmt_iterator gsi;
4504 for (gsi = gsi_start_bb (this_block); !gsi_end_p (gsi); gsi_next (&gsi))
4506 gimple stmt = gsi_stmt (gsi);
4508 if (gimple_code (stmt) != GIMPLE_CALL)
4510 call_fndecl = gimple_call_fndecl (stmt);
4511 if (call_fndecl == old_decl)
4514 fprintf (dump_file, "Adjusting recursive call");
4515 gimple_call_set_fndecl (stmt, node->decl);
4516 ipa_modify_call_arguments (NULL, stmt, adjustments);
4524 /* Perform all the modification required in IPA-SRA for NODE to have parameters
4525 as given in ADJUSTMENTS. Return true iff the CFG has been changed. */
4528 modify_function (struct cgraph_node *node, ipa_parm_adjustment_vec adjustments)
4530 struct cgraph_node *new_node;
4531 struct cgraph_edge *cs;
4533 VEC (cgraph_edge_p, heap) * redirect_callers;
4537 for (cs = node->callers; cs != NULL; cs = cs->next_caller)
4539 redirect_callers = VEC_alloc (cgraph_edge_p, heap, node_callers);
4540 for (cs = node->callers; cs != NULL; cs = cs->next_caller)
4541 VEC_quick_push (cgraph_edge_p, redirect_callers, cs);
4543 rebuild_cgraph_edges ();
4545 current_function_decl = NULL_TREE;
4547 new_node = cgraph_function_versioning (node, redirect_callers, NULL, NULL,
4548 NULL, NULL, "isra");
4549 current_function_decl = new_node->decl;
4550 push_cfun (DECL_STRUCT_FUNCTION (new_node->decl));
4552 ipa_modify_formal_parameters (current_function_decl, adjustments, "ISRA");
4553 cfg_changed = ipa_sra_modify_function_body (adjustments);
4554 sra_ipa_reset_debug_stmts (adjustments);
4555 convert_callers (new_node, node->decl, adjustments);
4556 cgraph_make_node_local (new_node);
4560 /* Return false the function is apparently unsuitable for IPA-SRA based on it's
4561 attributes, return true otherwise. NODE is the cgraph node of the current
4565 ipa_sra_preliminary_function_checks (struct cgraph_node *node)
4567 if (!cgraph_node_can_be_local_p (node))
4570 fprintf (dump_file, "Function not local to this compilation unit.\n");
4574 if (!node->local.can_change_signature)
4577 fprintf (dump_file, "Function can not change signature.\n");
4581 if (!tree_versionable_function_p (node->decl))
4584 fprintf (dump_file, "Function is not versionable.\n");
4588 if (DECL_VIRTUAL_P (current_function_decl))
4591 fprintf (dump_file, "Function is a virtual method.\n");
4595 if ((DECL_COMDAT (node->decl) || DECL_EXTERNAL (node->decl))
4596 && node->global.size >= MAX_INLINE_INSNS_AUTO)
4599 fprintf (dump_file, "Function too big to be made truly local.\n");
4607 "Function has no callers in this compilation unit.\n");
4614 fprintf (dump_file, "Function uses stdarg. \n");
4618 if (TYPE_ATTRIBUTES (TREE_TYPE (node->decl)))
4624 /* Perform early interprocedural SRA. */
4627 ipa_early_sra (void)
4629 struct cgraph_node *node = cgraph_node (current_function_decl);
4630 ipa_parm_adjustment_vec adjustments;
4633 if (!ipa_sra_preliminary_function_checks (node))
4637 sra_mode = SRA_MODE_EARLY_IPA;
4639 if (!find_param_candidates ())
4642 fprintf (dump_file, "Function has no IPA-SRA candidates.\n");
4646 if (!all_callers_have_enough_arguments_p (node))
4649 fprintf (dump_file, "There are callers with insufficient number of "
4654 bb_dereferences = XCNEWVEC (HOST_WIDE_INT,
4656 * last_basic_block_for_function (cfun));
4657 final_bbs = BITMAP_ALLOC (NULL);
4660 if (encountered_apply_args)
4663 fprintf (dump_file, "Function calls __builtin_apply_args().\n");
4667 if (encountered_unchangable_recursive_call)
4670 fprintf (dump_file, "Function calls itself with insufficient "
4671 "number of arguments.\n");
4675 adjustments = analyze_all_param_acesses ();
4679 ipa_dump_param_adjustments (dump_file, adjustments, current_function_decl);
4681 if (modify_function (node, adjustments))
4682 ret = TODO_update_ssa | TODO_cleanup_cfg;
4684 ret = TODO_update_ssa;
4685 VEC_free (ipa_parm_adjustment_t, heap, adjustments);
4687 statistics_counter_event (cfun, "Unused parameters deleted",
4688 sra_stats.deleted_unused_parameters);
4689 statistics_counter_event (cfun, "Scalar parameters converted to by-value",
4690 sra_stats.scalar_by_ref_to_by_val);
4691 statistics_counter_event (cfun, "Aggregate parameters broken up",
4692 sra_stats.aggregate_params_reduced);
4693 statistics_counter_event (cfun, "Aggregate parameter components created",
4694 sra_stats.param_reductions_created);
4697 BITMAP_FREE (final_bbs);
4698 free (bb_dereferences);
4700 sra_deinitialize ();
4704 /* Return if early ipa sra shall be performed. */
4706 ipa_early_sra_gate (void)
4708 return flag_ipa_sra && dbg_cnt (eipa_sra);
4711 struct gimple_opt_pass pass_early_ipa_sra =
4715 "eipa_sra", /* name */
4716 ipa_early_sra_gate, /* gate */
4717 ipa_early_sra, /* execute */
4720 0, /* static_pass_number */
4721 TV_IPA_SRA, /* tv_id */
4722 0, /* properties_required */
4723 0, /* properties_provided */
4724 0, /* properties_destroyed */
4725 0, /* todo_flags_start */
4726 TODO_dump_func | TODO_dump_cgraph /* todo_flags_finish */