gcc/tree-sra.c

   1 /* Scalar Replacement of Aggregates (SRA) converts some structure
   2    references into scalar references, exposing them to the scalar
   3    optimizers.
   4    Copyright (C) 2008-2017 Free Software Foundation, Inc.
   5    Contributed by Martin Jambor <mjambor@suse.cz>
   6
   7 This file is part of GCC.
   8
   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
  12 version.
  13
  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
  17 for more details.
  18
  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/>.  */
  22
  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.
  27
  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
  31    conversions.
  32
  33    Both passes operate in four stages:
  34
  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.
  38
  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.
  46
  47       On a related note, assign_link structures are created for every assign
  48       statement between candidate aggregates and attached to the related
  49       accesses.
  50
  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.
  55
  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).
  60
  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.
  64
  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.
  67
  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.  */
  73
  74 #include "config.h"
  75 #include "system.h"
  76 #include "coretypes.h"
  77 #include "backend.h"
  78 #include "target.h"
  79 #include "rtl.h"
  80 #include "tree.h"
  81 #include "gimple.h"
  82 #include "predict.h"
  83 #include "alloc-pool.h"
  84 #include "tree-pass.h"
  85 #include "ssa.h"
  86 #include "cgraph.h"
  87 #include "gimple-pretty-print.h"
  88 #include "alias.h"
  89 #include "fold-const.h"
  90 #include "tree-eh.h"
  91 #include "stor-layout.h"
  92 #include "gimplify.h"
  93 #include "gimple-iterator.h"
  94 #include "gimplify-me.h"
  95 #include "gimple-walk.h"
  96 #include "tree-cfg.h"
  97 #include "tree-dfa.h"
  98 #include "tree-ssa.h"
  99 #include "symbol-summary.h"
 100 #include "ipa-prop.h"
 101 #include "params.h"
 102 #include "dbgcnt.h"
 103 #include "tree-inline.h"
 104 #include "ipa-inline.h"
 105 #include "ipa-utils.h"
 106 #include "builtins.h"
 107
 108 /* Enumeration of all aggregate reductions we can do.  */
 109 enum sra_mode { SRA_MODE_EARLY_IPA,   /* early call regularization */
 110                 SRA_MODE_EARLY_INTRA, /* early intraprocedural SRA */
 111                 SRA_MODE_INTRA };     /* late intraprocedural SRA */
 112
 113 /* Global variable describing which aggregate reduction we are performing at
 114    the moment.  */
 115 static enum sra_mode sra_mode;
 116
 117 struct assign_link;
 118
 119 /* ACCESS represents each access to an aggregate variable (as a whole or a
 120    part).  It can also represent a group of accesses that refer to exactly the
 121    same fragment of an aggregate (i.e. those that have exactly the same offset
 122    and size).  Such representatives for a single aggregate, once determined,
 123    are linked in a linked list and have the group fields set.
 124
 125    Moreover, when doing intraprocedural SRA, a tree is built from those
 126    representatives (by the means of first_child and next_sibling pointers), in
 127    which all items in a subtree are "within" the root, i.e. their offset is
 128    greater or equal to offset of the root and offset+size is smaller or equal
 129    to offset+size of the root.  Children of an access are sorted by offset.
 130
 131    Note that accesses to parts of vector and complex number types always
 132    represented by an access to the whole complex number or a vector.  It is a
 133    duty of the modifying functions to replace them appropriately.  */
 134
 135 struct access
 136 {
 137   /* Values returned by  `get_ref_base_and_extent' for each component reference
 138      If EXPR isn't a component reference  just set `BASE = EXPR', `OFFSET = 0',
 139      `SIZE = TREE_SIZE (TREE_TYPE (expr))'.  */
 140   HOST_WIDE_INT offset;
 141   HOST_WIDE_INT size;
 142   tree base;
 143
 144   /* Expression.  It is context dependent so do not use it to create new
 145      expressions to access the original aggregate.  See PR 42154 for a
 146      testcase.  */
 147   tree expr;
 148   /* Type.  */
 149   tree type;
 150
 151   /* The statement this access belongs to.  */
 152   gimple *stmt;
 153
 154   /* Next group representative for this aggregate. */
 155   struct access *next_grp;
 156
 157   /* Pointer to the group representative.  Pointer to itself if the struct is
 158      the representative.  */
 159   struct access *group_representative;
 160
 161   /* If this access has any children (in terms of the definition above), this
 162      points to the first one.  */
 163   struct access *first_child;
 164
 165   /* In intraprocedural SRA, pointer to the next sibling in the access tree as
 166      described above.  In IPA-SRA this is a pointer to the next access
 167      belonging to the same group (having the same representative).  */
 168   struct access *next_sibling;
 169
 170   /* Pointers to the first and last element in the linked list of assign
 171      links.  */
 172   struct assign_link *first_link, *last_link;
 173
 174   /* Pointer to the next access in the work queue.  */
 175   struct access *next_queued;
 176
 177   /* Replacement variable for this access "region."  Never to be accessed
 178      directly, always only by the means of get_access_replacement() and only
 179      when grp_to_be_replaced flag is set.  */
 180   tree replacement_decl;
 181
 182   /* Is this access an access to a non-addressable field? */
 183   unsigned non_addressable : 1;
 184
 185   /* Is this access made in reverse storage order? */
 186   unsigned reverse : 1;
 187
 188   /* Is this particular access write access? */
 189   unsigned write : 1;
 190
 191   /* Is this access currently in the work queue?  */
 192   unsigned grp_queued : 1;
 193
 194   /* Does this group contain a write access?  This flag is propagated down the
 195      access tree.  */
 196   unsigned grp_write : 1;
 197
 198   /* Does this group contain a read access?  This flag is propagated down the
 199      access tree.  */
 200   unsigned grp_read : 1;
 201
 202   /* Does this group contain a read access that comes from an assignment
 203      statement?  This flag is propagated down the access tree.  */
 204   unsigned grp_assignment_read : 1;
 205
 206   /* Does this group contain a write access that comes from an assignment
 207      statement?  This flag is propagated down the access tree.  */
 208   unsigned grp_assignment_write : 1;
 209
 210   /* Does this group contain a read access through a scalar type?  This flag is
 211      not propagated in the access tree in any direction.  */
 212   unsigned grp_scalar_read : 1;
 213
 214   /* Does this group contain a write access through a scalar type?  This flag
 215      is not propagated in the access tree in any direction.  */
 216   unsigned grp_scalar_write : 1;
 217
 218   /* Is this access an artificial one created to scalarize some record
 219      entirely? */
 220   unsigned grp_total_scalarization : 1;
 221
 222   /* Other passes of the analysis use this bit to make function
 223      analyze_access_subtree create scalar replacements for this group if
 224      possible.  */
 225   unsigned grp_hint : 1;
 226
 227   /* Is the subtree rooted in this access fully covered by scalar
 228      replacements?  */
 229   unsigned grp_covered : 1;
 230
 231   /* If set to true, this access and all below it in an access tree must not be
 232      scalarized.  */
 233   unsigned grp_unscalarizable_region : 1;
 234
 235   /* Whether data have been written to parts of the aggregate covered by this
 236      access which is not to be scalarized.  This flag is propagated up in the
 237      access tree.  */
 238   unsigned grp_unscalarized_data : 1;
 239
 240   /* Does this access and/or group contain a write access through a
 241      BIT_FIELD_REF?  */
 242   unsigned grp_partial_lhs : 1;
 243
 244   /* Set when a scalar replacement should be created for this variable.  */
 245   unsigned grp_to_be_replaced : 1;
 246
 247   /* Set when we want a replacement for the sole purpose of having it in
 248      generated debug statements.  */
 249   unsigned grp_to_be_debug_replaced : 1;
 250
 251   /* Should TREE_NO_WARNING of a replacement be set?  */
 252   unsigned grp_no_warning : 1;
 253
 254   /* Is it possible that the group refers to data which might be (directly or
 255      otherwise) modified?  */
 256   unsigned grp_maybe_modified : 1;
 257
 258   /* Set when this is a representative of a pointer to scalar (i.e. by
 259      reference) parameter which we consider for turning into a plain scalar
 260      (i.e. a by value parameter).  */
 261   unsigned grp_scalar_ptr : 1;
 262
 263   /* Set when we discover that this pointer is not safe to dereference in the
 264      caller.  */
 265   unsigned grp_not_necessarilly_dereferenced : 1;
 266 };
 267
 268 typedef struct access *access_p;
 269
 270
 271 /* Alloc pool for allocating access structures.  */
 272 static object_allocator<struct access> access_pool ("SRA accesses");
 273
 274 /* A structure linking lhs and rhs accesses from an aggregate assignment.  They
 275    are used to propagate subaccesses from rhs to lhs as long as they don't
 276    conflict with what is already there.  */
 277 struct assign_link
 278 {
 279   struct access *lacc, *racc;
 280   struct assign_link *next;
 281 };
 282
 283 /* Alloc pool for allocating assign link structures.  */
 284 static object_allocator<assign_link> assign_link_pool ("SRA links");
 285
 286 /* Base (tree) -> Vector (vec<access_p> *) map.  */
 287 static hash_map<tree, auto_vec<access_p> > *base_access_vec;
 288
 289 /* Candidate hash table helpers.  */
 290
 291 struct uid_decl_hasher : nofree_ptr_hash <tree_node>
 292 {
 293   static inline hashval_t hash (const tree_node *);
 294   static inline bool equal (const tree_node *, const tree_node *);
 295 };
 296
 297 /* Hash a tree in a uid_decl_map.  */
 298
 299 inline hashval_t
 300 uid_decl_hasher::hash (const tree_node *item)
 301 {
 302   return item->decl_minimal.uid;
 303 }
 304
 305 /* Return true if the DECL_UID in both trees are equal.  */
 306
 307 inline bool
 308 uid_decl_hasher::equal (const tree_node *a, const tree_node *b)
 309 {
 310   return (a->decl_minimal.uid == b->decl_minimal.uid);
 311 }
 312
 313 /* Set of candidates.  */
 314 static bitmap candidate_bitmap;
 315 static hash_table<uid_decl_hasher> *candidates;
 316
 317 /* For a candidate UID return the candidates decl.  */
 318
 319 static inline tree
 320 candidate (unsigned uid)
 321 {
 322  tree_node t;
 323  t.decl_minimal.uid = uid;
 324  return candidates->find_with_hash (&t, static_cast <hashval_t> (uid));
 325 }
 326
 327 /* Bitmap of candidates which we should try to entirely scalarize away and
 328    those which cannot be (because they are and need be used as a whole).  */
 329 static bitmap should_scalarize_away_bitmap, cannot_scalarize_away_bitmap;
 330
 331 /* Bitmap of candidates in the constant pool, which cannot be scalarized
 332    because this would produce non-constant expressions (e.g. Ada).  */
 333 static bitmap disqualified_constants;
 334
 335 /* Obstack for creation of fancy names.  */
 336 static struct obstack name_obstack;
 337
 338 /* Head of a linked list of accesses that need to have its subaccesses
 339    propagated to their assignment counterparts. */
 340 static struct access *work_queue_head;
 341
 342 /* Number of parameters of the analyzed function when doing early ipa SRA.  */
 343 static int func_param_count;
 344
 345 /* scan_function sets the following to true if it encounters a call to
 346    __builtin_apply_args.  */
 347 static bool encountered_apply_args;
 348
 349 /* Set by scan_function when it finds a recursive call.  */
 350 static bool encountered_recursive_call;
 351
 352 /* Set by scan_function when it finds a recursive call with less actual
 353    arguments than formal parameters..  */
 354 static bool encountered_unchangable_recursive_call;
 355
 356 /* This is a table in which for each basic block and parameter there is a
 357    distance (offset + size) in that parameter which is dereferenced and
 358    accessed in that BB.  */
 359 static HOST_WIDE_INT *bb_dereferences;
 360 /* Bitmap of BBs that can cause the function to "stop" progressing by
 361    returning, throwing externally, looping infinitely or calling a function
 362    which might abort etc.. */
 363 static bitmap final_bbs;
 364
 365 /* Representative of no accesses at all. */
 366 static struct access  no_accesses_representant;
 367
 368 /* Predicate to test the special value.  */
 369
 370 static inline bool
 371 no_accesses_p (struct access *access)
 372 {
 373   return access == &no_accesses_representant;
 374 }
 375
 376 /* Dump contents of ACCESS to file F in a human friendly way.  If GRP is true,
 377    representative fields are dumped, otherwise those which only describe the
 378    individual access are.  */
 379
 380 static struct
 381 {
 382   /* Number of processed aggregates is readily available in
 383      analyze_all_variable_accesses and so is not stored here.  */
 384
 385   /* Number of created scalar replacements.  */
 386   int replacements;
 387
 388   /* Number of times sra_modify_expr or sra_modify_assign themselves changed an
 389      expression.  */
 390   int exprs;
 391
 392   /* Number of statements created by generate_subtree_copies.  */
 393   int subtree_copies;
 394
 395   /* Number of statements created by load_assign_lhs_subreplacements.  */
 396   int subreplacements;
 397
 398   /* Number of times sra_modify_assign has deleted a statement.  */
 399   int deleted;
 400
 401   /* Number of times sra_modify_assign has to deal with subaccesses of LHS and
 402      RHS reparately due to type conversions or nonexistent matching
 403      references.  */
 404   int separate_lhs_rhs_handling;
 405
 406   /* Number of parameters that were removed because they were unused.  */
 407   int deleted_unused_parameters;
 408
 409   /* Number of scalars passed as parameters by reference that have been
 410      converted to be passed by value.  */
 411   int scalar_by_ref_to_by_val;
 412
 413   /* Number of aggregate parameters that were replaced by one or more of their
 414      components.  */
 415   int aggregate_params_reduced;
 416
 417   /* Numbber of components created when splitting aggregate parameters.  */
 418   int param_reductions_created;
 419 } sra_stats;
 420
 421 static void
 422 dump_access (FILE *f, struct access *access, bool grp)
 423 {
 424   fprintf (f, "access { ");
 425   fprintf (f, "base = (%d)'", DECL_UID (access->base));
 426   print_generic_expr (f, access->base, 0);
 427   fprintf (f, "', offset = " HOST_WIDE_INT_PRINT_DEC, access->offset);
 428   fprintf (f, ", size = " HOST_WIDE_INT_PRINT_DEC, access->size);
 429   fprintf (f, ", expr = ");
 430   print_generic_expr (f, access->expr, 0);
 431   fprintf (f, ", type = ");
 432   print_generic_expr (f, access->type, 0);
 433   fprintf (f, ", non_addressable = %d, reverse = %d",
 434            access->non_addressable, access->reverse);
 435   if (grp)
 436     fprintf (f, ", grp_read = %d, grp_write = %d, grp_assignment_read = %d, "
 437              "grp_assignment_write = %d, grp_scalar_read = %d, "
 438              "grp_scalar_write = %d, grp_total_scalarization = %d, "
 439              "grp_hint = %d, grp_covered = %d, "
 440              "grp_unscalarizable_region = %d, grp_unscalarized_data = %d, "
 441              "grp_partial_lhs = %d, grp_to_be_replaced = %d, "
 442              "grp_to_be_debug_replaced = %d, grp_maybe_modified = %d, "
 443              "grp_not_necessarilly_dereferenced = %d\n",
 444              access->grp_read, access->grp_write, access->grp_assignment_read,
 445              access->grp_assignment_write, access->grp_scalar_read,
 446              access->grp_scalar_write, access->grp_total_scalarization,
 447              access->grp_hint, access->grp_covered,
 448              access->grp_unscalarizable_region, access->grp_unscalarized_data,
 449              access->grp_partial_lhs, access->grp_to_be_replaced,
 450              access->grp_to_be_debug_replaced, access->grp_maybe_modified,
 451              access->grp_not_necessarilly_dereferenced);
 452   else
 453     fprintf (f, ", write = %d, grp_total_scalarization = %d, "
 454              "grp_partial_lhs = %d\n",
 455              access->write, access->grp_total_scalarization,
 456              access->grp_partial_lhs);
 457 }
 458
 459 /* Dump a subtree rooted in ACCESS to file F, indent by LEVEL.  */
 460
 461 static void
 462 dump_access_tree_1 (FILE *f, struct access *access, int level)
 463 {
 464   do
 465     {
 466       int i;
 467
 468       for (i = 0; i < level; i++)
 469         fputs ("* ", dump_file);
 470
 471       dump_access (f, access, true);
 472
 473       if (access->first_child)
 474         dump_access_tree_1 (f, access->first_child, level + 1);
 475
 476       access = access->next_sibling;
 477     }
 478   while (access);
 479 }
 480
 481 /* Dump all access trees for a variable, given the pointer to the first root in
 482    ACCESS.  */
 483
 484 static void
 485 dump_access_tree (FILE *f, struct access *access)
 486 {
 487   for (; access; access = access->next_grp)
 488     dump_access_tree_1 (f, access, 0);
 489 }
 490
 491 /* Return true iff ACC is non-NULL and has subaccesses.  */
 492
 493 static inline bool
 494 access_has_children_p (struct access *acc)
 495 {
 496   return acc && acc->first_child;
 497 }
 498
 499 /* Return true iff ACC is (partly) covered by at least one replacement.  */
 500
 501 static bool
 502 access_has_replacements_p (struct access *acc)
 503 {
 504   struct access *child;
 505   if (acc->grp_to_be_replaced)
 506     return true;
 507   for (child = acc->first_child; child; child = child->next_sibling)
 508     if (access_has_replacements_p (child))
 509       return true;
 510   return false;
 511 }
 512
 513 /* Return a vector of pointers to accesses for the variable given in BASE or
 514    NULL if there is none.  */
 515
 516 static vec<access_p> *
 517 get_base_access_vector (tree base)
 518 {
 519   return base_access_vec->get (base);
 520 }
 521
 522 /* Find an access with required OFFSET and SIZE in a subtree of accesses rooted
 523    in ACCESS.  Return NULL if it cannot be found.  */
 524
 525 static struct access *
 526 find_access_in_subtree (struct access *access, HOST_WIDE_INT offset,
 527                         HOST_WIDE_INT size)
 528 {
 529   while (access && (access->offset != offset || access->size != size))
 530     {
 531       struct access *child = access->first_child;
 532
 533       while (child && (child->offset + child->size <= offset))
 534         child = child->next_sibling;
 535       access = child;
 536     }
 537
 538   return access;
 539 }
 540
 541 /* Return the first group representative for DECL or NULL if none exists.  */
 542
 543 static struct access *
 544 get_first_repr_for_decl (tree base)
 545 {
 546   vec<access_p> *access_vec;
 547
 548   access_vec = get_base_access_vector (base);
 549   if (!access_vec)
 550     return NULL;
 551
 552   return (*access_vec)[0];
 553 }
 554
 555 /* Find an access representative for the variable BASE and given OFFSET and
 556    SIZE.  Requires that access trees have already been built.  Return NULL if
 557    it cannot be found.  */
 558
 559 static struct access *
 560 get_var_base_offset_size_access (tree base, HOST_WIDE_INT offset,
 561                                  HOST_WIDE_INT size)
 562 {
 563   struct access *access;
 564
 565   access = get_first_repr_for_decl (base);
 566   while (access && (access->offset + access->size <= offset))
 567     access = access->next_grp;
 568   if (!access)
 569     return NULL;
 570
 571   return find_access_in_subtree (access, offset, size);
 572 }
 573
 574 /* Add LINK to the linked list of assign links of RACC.  */
 575 static void
 576 add_link_to_rhs (struct access *racc, struct assign_link *link)
 577 {
 578   gcc_assert (link->racc == racc);
 579
 580   if (!racc->first_link)
 581     {
 582       gcc_assert (!racc->last_link);
 583       racc->first_link = link;
 584     }
 585   else
 586     racc->last_link->next = link;
 587
 588   racc->last_link = link;
 589   link->next = NULL;
 590 }
 591
 592 /* Move all link structures in their linked list in OLD_RACC to the linked list
 593    in NEW_RACC.  */
 594 static void
 595 relink_to_new_repr (struct access *new_racc, struct access *old_racc)
 596 {
 597   if (!old_racc->first_link)
 598     {
 599       gcc_assert (!old_racc->last_link);
 600       return;
 601     }
 602
 603   if (new_racc->first_link)
 604     {
 605       gcc_assert (!new_racc->last_link->next);
 606       gcc_assert (!old_racc->last_link || !old_racc->last_link->next);
 607
 608       new_racc->last_link->next = old_racc->first_link;
 609       new_racc->last_link = old_racc->last_link;
 610     }
 611   else
 612     {
 613       gcc_assert (!new_racc->last_link);
 614
 615       new_racc->first_link = old_racc->first_link;
 616       new_racc->last_link = old_racc->last_link;
 617     }
 618   old_racc->first_link = old_racc->last_link = NULL;
 619 }
 620
 621 /* Add ACCESS to the work queue (which is actually a stack).  */
 622
 623 static void
 624 add_access_to_work_queue (struct access *access)
 625 {
 626   if (!access->grp_queued)
 627     {
 628       gcc_assert (!access->next_queued);
 629       access->next_queued = work_queue_head;
 630       access->grp_queued = 1;
 631       work_queue_head = access;
 632     }
 633 }
 634
 635 /* Pop an access from the work queue, and return it, assuming there is one.  */
 636
 637 static struct access *
 638 pop_access_from_work_queue (void)
 639 {
 640   struct access *access = work_queue_head;
 641
 642   work_queue_head = access->next_queued;
 643   access->next_queued = NULL;
 644   access->grp_queued = 0;
 645   return access;
 646 }
 647
 648
 649 /* Allocate necessary structures.  */
 650
 651 static void
 652 sra_initialize (void)
 653 {
 654   candidate_bitmap = BITMAP_ALLOC (NULL);
 655   candidates = new hash_table<uid_decl_hasher>
 656     (vec_safe_length (cfun->local_decls) / 2);
 657   should_scalarize_away_bitmap = BITMAP_ALLOC (NULL);
 658   cannot_scalarize_away_bitmap = BITMAP_ALLOC (NULL);
 659   disqualified_constants = BITMAP_ALLOC (NULL);
 660   gcc_obstack_init (&name_obstack);
 661   base_access_vec = new hash_map<tree, auto_vec<access_p> >;
 662   memset (&sra_stats, 0, sizeof (sra_stats));
 663   encountered_apply_args = false;
 664   encountered_recursive_call = false;
 665   encountered_unchangable_recursive_call = false;
 666 }
 667
 668 /* Deallocate all general structures.  */
 669
 670 static void
 671 sra_deinitialize (void)
 672 {
 673   BITMAP_FREE (candidate_bitmap);
 674   delete candidates;
 675   candidates = NULL;
 676   BITMAP_FREE (should_scalarize_away_bitmap);
 677   BITMAP_FREE (cannot_scalarize_away_bitmap);
 678   BITMAP_FREE (disqualified_constants);
 679   access_pool.release ();
 680   assign_link_pool.release ();
 681   obstack_free (&name_obstack, NULL);
 682
 683   delete base_access_vec;
 684 }
 685
 686 /* Return true if DECL is a VAR_DECL in the constant pool, false otherwise.  */
 687
 688 static bool constant_decl_p (tree decl)
 689 {
 690   return VAR_P (decl) && DECL_IN_CONSTANT_POOL (decl);
 691 }
 692
 693 /* Remove DECL from candidates for SRA and write REASON to the dump file if
 694    there is one.  */
 695 static void
 696 disqualify_candidate (tree decl, const char *reason)
 697 {
 698   if (bitmap_clear_bit (candidate_bitmap, DECL_UID (decl)))
 699     candidates->remove_elt_with_hash (decl, DECL_UID (decl));
 700   if (constant_decl_p (decl))
 701     bitmap_set_bit (disqualified_constants, DECL_UID (decl));
 702
 703   if (dump_file && (dump_flags & TDF_DETAILS))
 704     {
 705       fprintf (dump_file, "! Disqualifying ");
 706       print_generic_expr (dump_file, decl, 0);
 707       fprintf (dump_file, " - %s\n", reason);
 708     }
 709 }
 710
 711 /* Return true iff the type contains a field or an element which does not allow
 712    scalarization.  */
 713
 714 static bool
 715 type_internals_preclude_sra_p (tree type, const char **msg)
 716 {
 717   tree fld;
 718   tree et;
 719
 720   switch (TREE_CODE (type))
 721     {
 722     case RECORD_TYPE:
 723     case UNION_TYPE:
 724     case QUAL_UNION_TYPE:
 725       for (fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld))
 726         if (TREE_CODE (fld) == FIELD_DECL)
 727           {
 728             tree ft = TREE_TYPE (fld);
 729
 730             if (TREE_THIS_VOLATILE (fld))
 731               {
 732                 *msg = "volatile structure field";
 733                 return true;
 734               }
 735             if (!DECL_FIELD_OFFSET (fld))
 736               {
 737                 *msg = "no structure field offset";
 738                 return true;
 739               }
 740             if (!DECL_SIZE (fld))
 741               {
 742                 *msg = "zero structure field size";
 743                 return true;
 744               }
 745             if (!tree_fits_uhwi_p (DECL_FIELD_OFFSET (fld)))
 746               {
 747                 *msg = "structure field offset not fixed";
 748                 return true;
 749               }
 750             if (!tree_fits_uhwi_p (DECL_SIZE (fld)))
 751               {
 752                 *msg = "structure field size not fixed";
 753                 return true;
 754               }
 755             if (!tree_fits_shwi_p (bit_position (fld)))
 756               {
 757                 *msg = "structure field size too big";
 758                 return true;
 759               }
 760             if (AGGREGATE_TYPE_P (ft)
 761                     && int_bit_position (fld) % BITS_PER_UNIT != 0)
 762               {
 763                 *msg = "structure field is bit field";
 764                 return true;
 765               }
 766
 767             if (AGGREGATE_TYPE_P (ft) && type_internals_preclude_sra_p (ft, msg))
 768               return true;
 769           }
 770
 771       return false;
 772
 773     case ARRAY_TYPE:
 774       et = TREE_TYPE (type);
 775
 776       if (TYPE_VOLATILE (et))
 777         {
 778           *msg = "element type is volatile";
 779           return true;
 780         }
 781
 782       if (AGGREGATE_TYPE_P (et) && type_internals_preclude_sra_p (et, msg))
 783         return true;
 784
 785       return false;
 786
 787     default:
 788       return false;
 789     }
 790 }
 791
 792 /* If T is an SSA_NAME, return NULL if it is not a default def or return its
 793    base variable if it is.  Return T if it is not an SSA_NAME.  */
 794
 795 static tree
 796 get_ssa_base_param (tree t)
 797 {
 798   if (TREE_CODE (t) == SSA_NAME)
 799     {
 800       if (SSA_NAME_IS_DEFAULT_DEF (t))
 801         return SSA_NAME_VAR (t);
 802       else
 803         return NULL_TREE;
 804     }
 805   return t;
 806 }
 807
 808 /* Mark a dereference of BASE of distance DIST in a basic block tht STMT
 809    belongs to, unless the BB has already been marked as a potentially
 810    final.  */
 811
 812 static void
 813 mark_parm_dereference (tree base, HOST_WIDE_INT dist, gimple *stmt)
 814 {
 815   basic_block bb = gimple_bb (stmt);
 816   int idx, parm_index = 0;
 817   tree parm;
 818
 819   if (bitmap_bit_p (final_bbs, bb->index))
 820     return;
 821
 822   for (parm = DECL_ARGUMENTS (current_function_decl);
 823        parm && parm != base;
 824        parm = DECL_CHAIN (parm))
 825     parm_index++;
 826
 827   gcc_assert (parm_index < func_param_count);
 828
 829   idx = bb->index * func_param_count + parm_index;
 830   if (bb_dereferences[idx] < dist)
 831     bb_dereferences[idx] = dist;
 832 }
 833
 834 /* Allocate an access structure for BASE, OFFSET and SIZE, clear it, fill in
 835    the three fields.  Also add it to the vector of accesses corresponding to
 836    the base.  Finally, return the new access.  */
 837
 838 static struct access *
 839 create_access_1 (tree base, HOST_WIDE_INT offset, HOST_WIDE_INT size)
 840 {
 841   struct access *access = access_pool.allocate ();
 842
 843   memset (access, 0, sizeof (struct access));
 844   access->base = base;
 845   access->offset = offset;
 846   access->size = size;
 847
 848   base_access_vec->get_or_insert (base).safe_push (access);
 849
 850   return access;
 851 }
 852
 853 static bool maybe_add_sra_candidate (tree);
 854
 855 /* Create and insert access for EXPR. Return created access, or NULL if it is
 856    not possible.  Also scan for uses of constant pool as we go along and add
 857    to candidates.  */
 858
 859 static struct access *
 860 create_access (tree expr, gimple *stmt, bool write)
 861 {
 862   struct access *access;
 863   HOST_WIDE_INT offset, size, max_size;
 864   tree base = expr;
 865   bool reverse, ptr, unscalarizable_region = false;
 866
 867   base = get_ref_base_and_extent (expr, &offset, &size, &max_size, &reverse);
 868
 869   if (sra_mode == SRA_MODE_EARLY_IPA
 870       && TREE_CODE (base) == MEM_REF)
 871     {
 872       base = get_ssa_base_param (TREE_OPERAND (base, 0));
 873       if (!base)
 874         return NULL;
 875       ptr = true;
 876     }
 877   else
 878     ptr = false;
 879
 880   /* For constant-pool entries, check we can substitute the constant value.  */
 881   if (constant_decl_p (base)
 882       && (sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA))
 883     {
 884       gcc_assert (!bitmap_bit_p (disqualified_constants, DECL_UID (base)));
 885       if (expr != base
 886           && !is_gimple_reg_type (TREE_TYPE (expr))
 887           && dump_file && (dump_flags & TDF_DETAILS))
 888         {
 889           /* This occurs in Ada with accesses to ARRAY_RANGE_REFs,
 890              and elements of multidimensional arrays (which are
 891              multi-element arrays in their own right).  */
 892           fprintf (dump_file, "Allowing non-reg-type load of part"
 893                               " of constant-pool entry: ");
 894           print_generic_expr (dump_file, expr, 0);
 895         }
 896       maybe_add_sra_candidate (base);
 897     }
 898
 899   if (!DECL_P (base) || !bitmap_bit_p (candidate_bitmap, DECL_UID (base)))
 900     return NULL;
 901
 902   if (sra_mode == SRA_MODE_EARLY_IPA)
 903     {
 904       if (size < 0 || size != max_size)
 905         {
 906           disqualify_candidate (base, "Encountered a variable sized access.");
 907           return NULL;
 908         }
 909       if (TREE_CODE (expr) == COMPONENT_REF
 910           && DECL_BIT_FIELD (TREE_OPERAND (expr, 1)))
 911         {
 912           disqualify_candidate (base, "Encountered a bit-field access.");
 913           return NULL;
 914         }
 915       gcc_checking_assert ((offset % BITS_PER_UNIT) == 0);
 916
 917       if (ptr)
 918         mark_parm_dereference (base, offset + size, stmt);
 919     }
 920   else
 921     {
 922       if (size != max_size)
 923         {
 924           size = max_size;
 925           unscalarizable_region = true;
 926         }
 927       if (size < 0)
 928         {
 929           disqualify_candidate (base, "Encountered an unconstrained access.");
 930           return NULL;
 931         }
 932     }
 933
 934   access = create_access_1 (base, offset, size);
 935   access->expr = expr;
 936   access->type = TREE_TYPE (expr);
 937   access->write = write;
 938   access->grp_unscalarizable_region = unscalarizable_region;
 939   access->stmt = stmt;
 940   access->reverse = reverse;
 941
 942   if (TREE_CODE (expr) == COMPONENT_REF
 943       && DECL_NONADDRESSABLE_P (TREE_OPERAND (expr, 1)))
 944     access->non_addressable = 1;
 945
 946   return access;
 947 }
 948
 949
 950 /* Return true iff TYPE is scalarizable - i.e. a RECORD_TYPE or fixed-length
 951    ARRAY_TYPE with fields that are either of gimple register types (excluding
 952    bit-fields) or (recursively) scalarizable types.  */
 953
 954 static bool
 955 scalarizable_type_p (tree type)
 956 {
 957   gcc_assert (!is_gimple_reg_type (type));
 958   if (type_contains_placeholder_p (type))
 959     return false;
 960
 961   switch (TREE_CODE (type))
 962   {
 963   case RECORD_TYPE:
 964     for (tree fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld))
 965       if (TREE_CODE (fld) == FIELD_DECL)
 966         {
 967           tree ft = TREE_TYPE (fld);
 968
 969           if (DECL_BIT_FIELD (fld))
 970             return false;
 971
 972           if (!is_gimple_reg_type (ft)
 973               && !scalarizable_type_p (ft))
 974             return false;
 975         }
 976
 977     return true;
 978
 979   case ARRAY_TYPE:
 980     {
 981       if (TYPE_DOMAIN (type) == NULL_TREE
 982           || !tree_fits_shwi_p (TYPE_SIZE (type))
 983           || !tree_fits_shwi_p (TYPE_SIZE (TREE_TYPE (type)))
 984           || (tree_to_shwi (TYPE_SIZE (TREE_TYPE (type))) <= 0)
 985           || !tree_fits_shwi_p (TYPE_MIN_VALUE (TYPE_DOMAIN (type))))
 986         return false;
 987       if (tree_to_shwi (TYPE_SIZE (type)) == 0
 988           && TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL_TREE)
 989         /* Zero-element array, should not prevent scalarization.  */
 990         ;
 991       else if ((tree_to_shwi (TYPE_SIZE (type)) <= 0)
 992                || !tree_fits_shwi_p (TYPE_MAX_VALUE (TYPE_DOMAIN (type))))
 993         /* Variable-length array, do not allow scalarization.  */
 994         return false;
 995
 996       tree elem = TREE_TYPE (type);
 997       if (!is_gimple_reg_type (elem)
 998          && !scalarizable_type_p (elem))
 999         return false;
1000       return true;
1001     }
1002   default:
1003     return false;
1004   }
1005 }
1006
1007 static void scalarize_elem (tree, HOST_WIDE_INT, HOST_WIDE_INT, bool, tree, tree);
1008
1009 /* Create total_scalarization accesses for all scalar fields of a member
1010    of type DECL_TYPE conforming to scalarizable_type_p.  BASE
1011    must be the top-most VAR_DECL representing the variable; within that,
1012    OFFSET locates the member and REF must be the memory reference expression for
1013    the member.  */
1014
1015 static void
1016 completely_scalarize (tree base, tree decl_type, HOST_WIDE_INT offset, tree ref)
1017 {
1018   switch (TREE_CODE (decl_type))
1019     {
1020     case RECORD_TYPE:
1021       for (tree fld = TYPE_FIELDS (decl_type); fld; fld = DECL_CHAIN (fld))
1022         if (TREE_CODE (fld) == FIELD_DECL)
1023           {
1024             HOST_WIDE_INT pos = offset + int_bit_position (fld);
1025             tree ft = TREE_TYPE (fld);
1026             tree nref = build3 (COMPONENT_REF, ft, ref, fld, NULL_TREE);
1027
1028             scalarize_elem (base, pos, tree_to_uhwi (DECL_SIZE (fld)),
1029                             TYPE_REVERSE_STORAGE_ORDER (decl_type),
1030                             nref, ft);
1031           }
1032       break;
1033     case ARRAY_TYPE:
1034       {
1035         tree elemtype = TREE_TYPE (decl_type);
1036         tree elem_size = TYPE_SIZE (elemtype);
1037         gcc_assert (elem_size && tree_fits_shwi_p (elem_size));
1038         HOST_WIDE_INT el_size = tree_to_shwi (elem_size);
1039         gcc_assert (el_size > 0);
1040
1041         tree minidx = TYPE_MIN_VALUE (TYPE_DOMAIN (decl_type));
1042         gcc_assert (TREE_CODE (minidx) == INTEGER_CST);
1043         tree maxidx = TYPE_MAX_VALUE (TYPE_DOMAIN (decl_type));
1044         /* Skip (some) zero-length arrays; others have MAXIDX == MINIDX - 1.  */
1045         if (maxidx)
1046           {
1047             gcc_assert (TREE_CODE (maxidx) == INTEGER_CST);
1048             tree domain = TYPE_DOMAIN (decl_type);
1049             /* MINIDX and MAXIDX are inclusive, and must be interpreted in
1050                DOMAIN (e.g. signed int, whereas min/max may be size_int).  */
1051             offset_int idx = wi::to_offset (minidx);
1052             offset_int max = wi::to_offset (maxidx);
1053             if (!TYPE_UNSIGNED (domain))
1054               {
1055                 idx = wi::sext (idx, TYPE_PRECISION (domain));
1056                 max = wi::sext (max, TYPE_PRECISION (domain));
1057               }
1058             for (int el_off = offset; idx <= max; ++idx)
1059               {
1060                 tree nref = build4 (ARRAY_REF, elemtype,
1061                                     ref,
1062                                     wide_int_to_tree (domain, idx),
1063                                     NULL_TREE, NULL_TREE);
1064                 scalarize_elem (base, el_off, el_size,
1065                                 TYPE_REVERSE_STORAGE_ORDER (decl_type),
1066                                 nref, elemtype);
1067                 el_off += el_size;
1068               }
1069           }
1070       }
1071       break;
1072     default:
1073       gcc_unreachable ();
1074     }
1075 }
1076
1077 /* Create total_scalarization accesses for a member of type TYPE, which must
1078    satisfy either is_gimple_reg_type or scalarizable_type_p.  BASE must be the
1079    top-most VAR_DECL representing the variable; within that, POS and SIZE locate
1080    the member, REVERSE gives its torage order. and REF must be the reference
1081    expression for it.  */
1082
1083 static void
1084 scalarize_elem (tree base, HOST_WIDE_INT pos, HOST_WIDE_INT size, bool reverse,
1085                 tree ref, tree type)
1086 {
1087   if (is_gimple_reg_type (type))
1088   {
1089     struct access *access = create_access_1 (base, pos, size);
1090     access->expr = ref;
1091     access->type = type;
1092     access->grp_total_scalarization = 1;
1093     access->reverse = reverse;
1094     /* Accesses for intraprocedural SRA can have their stmt NULL.  */
1095   }
1096   else
1097     completely_scalarize (base, type, pos, ref);
1098 }
1099
1100 /* Create a total_scalarization access for VAR as a whole.  VAR must be of a
1101    RECORD_TYPE or ARRAY_TYPE conforming to scalarizable_type_p.  */
1102
1103 static void
1104 create_total_scalarization_access (tree var)
1105 {
1106   HOST_WIDE_INT size = tree_to_uhwi (DECL_SIZE (var));
1107   struct access *access;
1108
1109   access = create_access_1 (var, 0, size);
1110   access->expr = var;
1111   access->type = TREE_TYPE (var);
1112   access->grp_total_scalarization = 1;
1113 }
1114
1115 /* Return true if REF has an VIEW_CONVERT_EXPR somewhere in it.  */
1116
1117 static inline bool
1118 contains_view_convert_expr_p (const_tree ref)
1119 {
1120   while (handled_component_p (ref))
1121     {
1122       if (TREE_CODE (ref) == VIEW_CONVERT_EXPR)
1123         return true;
1124       ref = TREE_OPERAND (ref, 0);
1125     }
1126
1127   return false;
1128 }
1129
1130 /* Search the given tree for a declaration by skipping handled components and
1131    exclude it from the candidates.  */
1132
1133 static void
1134 disqualify_base_of_expr (tree t, const char *reason)
1135 {
1136   t = get_base_address (t);
1137   if (sra_mode == SRA_MODE_EARLY_IPA
1138       && TREE_CODE (t) == MEM_REF)
1139     t = get_ssa_base_param (TREE_OPERAND (t, 0));
1140
1141   if (t && DECL_P (t))
1142     disqualify_candidate (t, reason);
1143 }
1144
1145 /* Scan expression EXPR and create access structures for all accesses to
1146    candidates for scalarization.  Return the created access or NULL if none is
1147    created.  */
1148
1149 static struct access *
1150 build_access_from_expr_1 (tree expr, gimple *stmt, bool write)
1151 {
1152   struct access *ret = NULL;
1153   bool partial_ref;
1154
1155   if (TREE_CODE (expr) == BIT_FIELD_REF
1156       || TREE_CODE (expr) == IMAGPART_EXPR
1157       || TREE_CODE (expr) == REALPART_EXPR)
1158     {
1159       expr = TREE_OPERAND (expr, 0);
1160       partial_ref = true;
1161     }
1162   else
1163     partial_ref = false;
1164
1165   /* We need to dive through V_C_Es in order to get the size of its parameter
1166      and not the result type.  Ada produces such statements.  We are also
1167      capable of handling the topmost V_C_E but not any of those buried in other
1168      handled components.  */
1169   if (TREE_CODE (expr) == VIEW_CONVERT_EXPR && !storage_order_barrier_p (expr))
1170     expr = TREE_OPERAND (expr, 0);
1171
1172   if (contains_view_convert_expr_p (expr))
1173     {
1174       disqualify_base_of_expr (expr, "V_C_E under a different handled "
1175                                "component.");
1176       return NULL;
1177     }
1178   if (TREE_THIS_VOLATILE (expr))
1179     {
1180       disqualify_base_of_expr (expr, "part of a volatile reference.");
1181       return NULL;
1182     }
1183
1184   switch (TREE_CODE (expr))
1185     {
1186     case MEM_REF:
1187       if (TREE_CODE (TREE_OPERAND (expr, 0)) != ADDR_EXPR
1188           && sra_mode != SRA_MODE_EARLY_IPA)
1189         return NULL;
1190       /* fall through */
1191     case VAR_DECL:
1192     case PARM_DECL:
1193     case RESULT_DECL:
1194     case COMPONENT_REF:
1195     case ARRAY_REF:
1196     case ARRAY_RANGE_REF:
1197       ret = create_access (expr, stmt, write);
1198       break;
1199
1200     default:
1201       break;
1202     }
1203
1204   if (write && partial_ref && ret)
1205     ret->grp_partial_lhs = 1;
1206
1207   return ret;
1208 }
1209
1210 /* Scan expression EXPR and create access structures for all accesses to
1211    candidates for scalarization.  Return true if any access has been inserted.
1212    STMT must be the statement from which the expression is taken, WRITE must be
1213    true if the expression is a store and false otherwise. */
1214
1215 static bool
1216 build_access_from_expr (tree expr, gimple *stmt, bool write)
1217 {
1218   struct access *access;
1219
1220   access = build_access_from_expr_1 (expr, stmt, write);
1221   if (access)
1222     {
1223       /* This means the aggregate is accesses as a whole in a way other than an
1224          assign statement and thus cannot be removed even if we had a scalar
1225          replacement for everything.  */
1226       if (cannot_scalarize_away_bitmap)
1227         bitmap_set_bit (cannot_scalarize_away_bitmap, DECL_UID (access->base));
1228       return true;
1229     }
1230   return false;
1231 }
1232
1233 /* Return the single non-EH successor edge of BB or NULL if there is none or
1234    more than one.  */
1235
1236 static edge
1237 single_non_eh_succ (basic_block bb)
1238 {
1239   edge e, res = NULL;
1240   edge_iterator ei;
1241
1242   FOR_EACH_EDGE (e, ei, bb->succs)
1243     if (!(e->flags & EDGE_EH))
1244       {
1245         if (res)
1246           return NULL;
1247         res = e;
1248       }
1249
1250   return res;
1251 }
1252
1253 /* Disqualify LHS and RHS for scalarization if STMT has to terminate its BB and
1254    there is no alternative spot where to put statements SRA might need to
1255    generate after it.  The spot we are looking for is an edge leading to a
1256    single non-EH successor, if it exists and is indeed single.  RHS may be
1257    NULL, in that case ignore it.  */
1258
1259 static bool
1260 disqualify_if_bad_bb_terminating_stmt (gimple *stmt, tree lhs, tree rhs)
1261 {
1262   if ((sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA)
1263       && stmt_ends_bb_p (stmt))
1264     {
1265       if (single_non_eh_succ (gimple_bb (stmt)))
1266         return false;
1267
1268       disqualify_base_of_expr (lhs, "LHS of a throwing stmt.");
1269       if (rhs)
1270         disqualify_base_of_expr (rhs, "RHS of a throwing stmt.");
1271       return true;
1272     }
1273   return false;
1274 }
1275
1276 /* Scan expressions occurring in STMT, create access structures for all accesses
1277    to candidates for scalarization and remove those candidates which occur in
1278    statements or expressions that prevent them from being split apart.  Return
1279    true if any access has been inserted.  */
1280
1281 static bool
1282 build_accesses_from_assign (gimple *stmt)
1283 {
1284   tree lhs, rhs;
1285   struct access *lacc, *racc;
1286
1287   if (!gimple_assign_single_p (stmt)
1288       /* Scope clobbers don't influence scalarization.  */
1289       || gimple_clobber_p (stmt))
1290     return false;
1291
1292   lhs = gimple_assign_lhs (stmt);
1293   rhs = gimple_assign_rhs1 (stmt);
1294
1295   if (disqualify_if_bad_bb_terminating_stmt (stmt, lhs, rhs))
1296     return false;
1297
1298   racc = build_access_from_expr_1 (rhs, stmt, false);
1299   lacc = build_access_from_expr_1 (lhs, stmt, true);
1300
1301   if (lacc)
1302     {
1303       lacc->grp_assignment_write = 1;
1304       if (storage_order_barrier_p (rhs))
1305         lacc->grp_unscalarizable_region = 1;
1306     }
1307
1308   if (racc)
1309     {
1310       racc->grp_assignment_read = 1;
1311       if (should_scalarize_away_bitmap && !gimple_has_volatile_ops (stmt)
1312           && !is_gimple_reg_type (racc->type))
1313         bitmap_set_bit (should_scalarize_away_bitmap, DECL_UID (racc->base));
1314       if (storage_order_barrier_p (lhs))
1315         racc->grp_unscalarizable_region = 1;
1316     }
1317
1318   if (lacc && racc
1319       && (sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA)
1320       && !lacc->grp_unscalarizable_region
1321       && !racc->grp_unscalarizable_region
1322       && AGGREGATE_TYPE_P (TREE_TYPE (lhs))
1323       && lacc->size == racc->size
1324       && useless_type_conversion_p (lacc->type, racc->type))
1325     {
1326       struct assign_link *link;
1327
1328       link = assign_link_pool.allocate ();
1329       memset (link, 0, sizeof (struct assign_link));
1330
1331       link->lacc = lacc;
1332       link->racc = racc;
1333
1334       add_link_to_rhs (racc, link);
1335     }
1336
1337   return lacc || racc;
1338 }
1339
1340 /* Callback of walk_stmt_load_store_addr_ops visit_addr used to determine
1341    GIMPLE_ASM operands with memory constrains which cannot be scalarized.  */
1342
1343 static bool
1344 asm_visit_addr (gimple *, tree op, tree, void *)
1345 {
1346   op = get_base_address (op);
1347   if (op
1348       && DECL_P (op))
1349     disqualify_candidate (op, "Non-scalarizable GIMPLE_ASM operand.");
1350
1351   return false;
1352 }
1353
1354 /* Return true iff callsite CALL has at least as many actual arguments as there
1355    are formal parameters of the function currently processed by IPA-SRA and
1356    that their types match.  */
1357
1358 static inline bool
1359 callsite_arguments_match_p (gimple *call)
1360 {
1361   if (gimple_call_num_args (call) < (unsigned) func_param_count)
1362     return false;
1363
1364   tree parm;
1365   int i;
1366   for (parm = DECL_ARGUMENTS (current_function_decl), i = 0;
1367        parm;
1368        parm = DECL_CHAIN (parm), i++)
1369     {
1370       tree arg = gimple_call_arg (call, i);
1371       if (!useless_type_conversion_p (TREE_TYPE (parm), TREE_TYPE (arg)))
1372         return false;
1373     }
1374   return true;
1375 }
1376
1377 /* Scan function and look for interesting expressions and create access
1378    structures for them.  Return true iff any access is created.  */
1379
1380 static bool
1381 scan_function (void)
1382 {
1383   basic_block bb;
1384   bool ret = false;
1385
1386   FOR_EACH_BB_FN (bb, cfun)
1387     {
1388       gimple_stmt_iterator gsi;
1389       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1390         {
1391           gimple *stmt = gsi_stmt (gsi);
1392           tree t;
1393           unsigned i;
1394
1395           if (final_bbs && stmt_can_throw_external (stmt))
1396             bitmap_set_bit (final_bbs, bb->index);
1397           switch (gimple_code (stmt))
1398             {
1399             case GIMPLE_RETURN:
1400               t = gimple_return_retval (as_a <greturn *> (stmt));
1401               if (t != NULL_TREE)
1402                 ret |= build_access_from_expr (t, stmt, false);
1403               if (final_bbs)
1404                 bitmap_set_bit (final_bbs, bb->index);
1405               break;
1406
1407             case GIMPLE_ASSIGN:
1408               ret |= build_accesses_from_assign (stmt);
1409               break;
1410
1411             case GIMPLE_CALL:
1412               for (i = 0; i < gimple_call_num_args (stmt); i++)
1413                 ret |= build_access_from_expr (gimple_call_arg (stmt, i),
1414                                                stmt, false);
1415
1416               if (sra_mode == SRA_MODE_EARLY_IPA)
1417                 {
1418                   tree dest = gimple_call_fndecl (stmt);
1419                   int flags = gimple_call_flags (stmt);
1420
1421                   if (dest)
1422                     {
1423                       if (DECL_BUILT_IN_CLASS (dest) == BUILT_IN_NORMAL
1424                           && DECL_FUNCTION_CODE (dest) == BUILT_IN_APPLY_ARGS)
1425                         encountered_apply_args = true;
1426                       if (recursive_call_p (current_function_decl, dest))
1427                         {
1428                           encountered_recursive_call = true;
1429                           if (!callsite_arguments_match_p (stmt))
1430                             encountered_unchangable_recursive_call = true;
1431                         }
1432                     }
1433
1434                   if (final_bbs
1435                       && (flags & (ECF_CONST | ECF_PURE)) == 0)
1436                     bitmap_set_bit (final_bbs, bb->index);
1437                 }
1438
1439               t = gimple_call_lhs (stmt);
1440               if (t && !disqualify_if_bad_bb_terminating_stmt (stmt, t, NULL))
1441                 ret |= build_access_from_expr (t, stmt, true);
1442               break;
1443
1444             case GIMPLE_ASM:
1445               {
1446                 gasm *asm_stmt = as_a <gasm *> (stmt);
1447                 walk_stmt_load_store_addr_ops (asm_stmt, NULL, NULL, NULL,
1448                                                asm_visit_addr);
1449                 if (final_bbs)
1450                   bitmap_set_bit (final_bbs, bb->index);
1451
1452                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
1453                   {
1454                     t = TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
1455                     ret |= build_access_from_expr (t, asm_stmt, false);
1456                   }
1457                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
1458                   {
1459                     t = TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
1460                     ret |= build_access_from_expr (t, asm_stmt, true);
1461                   }
1462               }
1463               break;
1464
1465             default:
1466               break;
1467             }
1468         }
1469     }
1470
1471   return ret;
1472 }
1473
1474 /* Helper of QSORT function. There are pointers to accesses in the array.  An
1475    access is considered smaller than another if it has smaller offset or if the
1476    offsets are the same but is size is bigger. */
1477
1478 static int
1479 compare_access_positions (const void *a, const void *b)
1480 {
1481   const access_p *fp1 = (const access_p *) a;
1482   const access_p *fp2 = (const access_p *) b;
1483   const access_p f1 = *fp1;
1484   const access_p f2 = *fp2;
1485
1486   if (f1->offset != f2->offset)
1487     return f1->offset < f2->offset ? -1 : 1;
1488
1489   if (f1->size == f2->size)
1490     {
1491       if (f1->type == f2->type)
1492         return 0;
1493       /* Put any non-aggregate type before any aggregate type.  */
1494       else if (!is_gimple_reg_type (f1->type)
1495           && is_gimple_reg_type (f2->type))
1496         return 1;
1497       else if (is_gimple_reg_type (f1->type)
1498                && !is_gimple_reg_type (f2->type))
1499         return -1;
1500       /* Put any complex or vector type before any other scalar type.  */
1501       else if (TREE_CODE (f1->type) != COMPLEX_TYPE
1502                && TREE_CODE (f1->type) != VECTOR_TYPE
1503                && (TREE_CODE (f2->type) == COMPLEX_TYPE
1504                    || TREE_CODE (f2->type) == VECTOR_TYPE))
1505         return 1;
1506       else if ((TREE_CODE (f1->type) == COMPLEX_TYPE
1507                 || TREE_CODE (f1->type) == VECTOR_TYPE)
1508                && TREE_CODE (f2->type) != COMPLEX_TYPE
1509                && TREE_CODE (f2->type) != VECTOR_TYPE)
1510         return -1;
1511       /* Put the integral type with the bigger precision first.  */
1512       else if (INTEGRAL_TYPE_P (f1->type)
1513                && INTEGRAL_TYPE_P (f2->type))
1514         return TYPE_PRECISION (f2->type) - TYPE_PRECISION (f1->type);
1515       /* Put any integral type with non-full precision last.  */
1516       else if (INTEGRAL_TYPE_P (f1->type)
1517                && (TREE_INT_CST_LOW (TYPE_SIZE (f1->type))
1518                    != TYPE_PRECISION (f1->type)))
1519         return 1;
1520       else if (INTEGRAL_TYPE_P (f2->type)
1521                && (TREE_INT_CST_LOW (TYPE_SIZE (f2->type))
1522                    != TYPE_PRECISION (f2->type)))
1523         return -1;
1524       /* Stabilize the sort.  */
1525       return TYPE_UID (f1->type) - TYPE_UID (f2->type);
1526     }
1527
1528   /* We want the bigger accesses first, thus the opposite operator in the next
1529      line: */
1530   return f1->size > f2->size ? -1 : 1;
1531 }
1532
1533
1534 /* Append a name of the declaration to the name obstack.  A helper function for
1535    make_fancy_name.  */
1536
1537 static void
1538 make_fancy_decl_name (tree decl)
1539 {
1540   char buffer[32];
1541
1542   tree name = DECL_NAME (decl);
1543   if (name)
1544     obstack_grow (&name_obstack, IDENTIFIER_POINTER (name),
1545                   IDENTIFIER_LENGTH (name));
1546   else
1547     {
1548       sprintf (buffer, "D%u", DECL_UID (decl));
1549       obstack_grow (&name_obstack, buffer, strlen (buffer));
1550     }
1551 }
1552
1553 /* Helper for make_fancy_name.  */
1554
1555 static void
1556 make_fancy_name_1 (tree expr)
1557 {
1558   char buffer[32];
1559   tree index;
1560
1561   if (DECL_P (expr))
1562     {
1563       make_fancy_decl_name (expr);
1564       return;
1565     }
1566
1567   switch (TREE_CODE (expr))
1568     {
1569     case COMPONENT_REF:
1570       make_fancy_name_1 (TREE_OPERAND (expr, 0));
1571       obstack_1grow (&name_obstack, '$');
1572       make_fancy_decl_name (TREE_OPERAND (expr, 1));
1573       break;
1574
1575     case ARRAY_REF:
1576       make_fancy_name_1 (TREE_OPERAND (expr, 0));
1577       obstack_1grow (&name_obstack, '$');
1578       /* Arrays with only one element may not have a constant as their
1579          index. */
1580       index = TREE_OPERAND (expr, 1);
1581       if (TREE_CODE (index) != INTEGER_CST)
1582         break;
1583       sprintf (buffer, HOST_WIDE_INT_PRINT_DEC, TREE_INT_CST_LOW (index));
1584       obstack_grow (&name_obstack, buffer, strlen (buffer));
1585       break;
1586
1587     case ADDR_EXPR:
1588       make_fancy_name_1 (TREE_OPERAND (expr, 0));
1589       break;
1590
1591     case MEM_REF:
1592       make_fancy_name_1 (TREE_OPERAND (expr, 0));
1593       if (!integer_zerop (TREE_OPERAND (expr, 1)))
1594         {
1595           obstack_1grow (&name_obstack, '$');
1596           sprintf (buffer, HOST_WIDE_INT_PRINT_DEC,
1597                    TREE_INT_CST_LOW (TREE_OPERAND (expr, 1)));
1598           obstack_grow (&name_obstack, buffer, strlen (buffer));
1599         }
1600       break;
1601
1602     case BIT_FIELD_REF:
1603     case REALPART_EXPR:
1604     case IMAGPART_EXPR:
1605       gcc_unreachable ();       /* we treat these as scalars.  */
1606       break;
1607     default:
1608       break;
1609     }
1610 }
1611
1612 /* Create a human readable name for replacement variable of ACCESS.  */
1613
1614 static char *
1615 make_fancy_name (tree expr)
1616 {
1617   make_fancy_name_1 (expr);
1618   obstack_1grow (&name_obstack, '\0');
1619   return XOBFINISH (&name_obstack, char *);
1620 }
1621
1622 /* Construct a MEM_REF that would reference a part of aggregate BASE of type
1623    EXP_TYPE at the given OFFSET and with storage order REVERSE.  If BASE is
1624    something for which get_addr_base_and_unit_offset returns NULL, gsi must
1625    be non-NULL and is used to insert new statements either before or below
1626    the current one as specified by INSERT_AFTER.  This function is not capable
1627    of handling bitfields.  */
1628
1629 tree
1630 build_ref_for_offset (location_t loc, tree base, HOST_WIDE_INT offset,
1631                       bool reverse, tree exp_type, gimple_stmt_iterator *gsi,
1632                       bool insert_after)
1633 {
1634   tree prev_base = base;
1635   tree off;
1636   tree mem_ref;
1637   HOST_WIDE_INT base_offset;
1638   unsigned HOST_WIDE_INT misalign;
1639   unsigned int align;
1640
1641   gcc_checking_assert (offset % BITS_PER_UNIT == 0);
1642   get_object_alignment_1 (base, &align, &misalign);
1643   base = get_addr_base_and_unit_offset (base, &base_offset);
1644
1645   /* get_addr_base_and_unit_offset returns NULL for references with a variable
1646      offset such as array[var_index].  */
1647   if (!base)
1648     {
1649       gassign *stmt;
1650       tree tmp, addr;
1651
1652       gcc_checking_assert (gsi);
1653       tmp = make_ssa_name (build_pointer_type (TREE_TYPE (prev_base)));
1654       addr = build_fold_addr_expr (unshare_expr (prev_base));
1655       STRIP_USELESS_TYPE_CONVERSION (addr);
1656       stmt = gimple_build_assign (tmp, addr);
1657       gimple_set_location (stmt, loc);
1658       if (insert_after)
1659         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
1660       else
1661         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
1662
1663       off = build_int_cst (reference_alias_ptr_type (prev_base),
1664                            offset / BITS_PER_UNIT);
1665       base = tmp;
1666     }
1667   else if (TREE_CODE (base) == MEM_REF)
1668     {
1669       off = build_int_cst (TREE_TYPE (TREE_OPERAND (base, 1)),
1670                            base_offset + offset / BITS_PER_UNIT);
1671       off = int_const_binop (PLUS_EXPR, TREE_OPERAND (base, 1), off);
1672       base = unshare_expr (TREE_OPERAND (base, 0));
1673     }
1674   else
1675     {
1676       off = build_int_cst (reference_alias_ptr_type (prev_base),
1677                            base_offset + offset / BITS_PER_UNIT);
1678       base = build_fold_addr_expr (unshare_expr (base));
1679     }
1680
1681   misalign = (misalign + offset) & (align - 1);
1682   if (misalign != 0)
1683     align = least_bit_hwi (misalign);
1684   if (align != TYPE_ALIGN (exp_type))
1685     exp_type = build_aligned_type (exp_type, align);
1686
1687   mem_ref = fold_build2_loc (loc, MEM_REF, exp_type, base, off);
1688   REF_REVERSE_STORAGE_ORDER (mem_ref) = reverse;
1689   if (TREE_THIS_VOLATILE (prev_base))
1690     TREE_THIS_VOLATILE (mem_ref) = 1;
1691   if (TREE_SIDE_EFFECTS (prev_base))
1692     TREE_SIDE_EFFECTS (mem_ref) = 1;
1693   return mem_ref;
1694 }
1695
1696 /* Construct a memory reference to a part of an aggregate BASE at the given
1697    OFFSET and of the same type as MODEL.  In case this is a reference to a
1698    bit-field, the function will replicate the last component_ref of model's
1699    expr to access it.  GSI and INSERT_AFTER have the same meaning as in
1700    build_ref_for_offset.  */
1701
1702 static tree
1703 build_ref_for_model (location_t loc, tree base, HOST_WIDE_INT offset,
1704                      struct access *model, gimple_stmt_iterator *gsi,
1705                      bool insert_after)
1706 {
1707   if (TREE_CODE (model->expr) == COMPONENT_REF
1708       && DECL_BIT_FIELD (TREE_OPERAND (model->expr, 1)))
1709     {
1710       /* This access represents a bit-field.  */
1711       tree t, exp_type, fld = TREE_OPERAND (model->expr, 1);
1712
1713       offset -= int_bit_position (fld);
1714       exp_type = TREE_TYPE (TREE_OPERAND (model->expr, 0));
1715       t = build_ref_for_offset (loc, base, offset, model->reverse, exp_type,
1716                                 gsi, insert_after);
1717       /* The flag will be set on the record type.  */
1718       REF_REVERSE_STORAGE_ORDER (t) = 0;
1719       return fold_build3_loc (loc, COMPONENT_REF, TREE_TYPE (fld), t, fld,
1720                               NULL_TREE);
1721     }
1722   else
1723     return
1724       build_ref_for_offset (loc, base, offset, model->reverse, model->type,
1725                             gsi, insert_after);
1726 }
1727
1728 /* Attempt to build a memory reference that we could but into a gimple
1729    debug_bind statement.  Similar to build_ref_for_model but punts if it has to
1730    create statements and return s NULL instead.  This function also ignores
1731    alignment issues and so its results should never end up in non-debug
1732    statements.  */
1733
1734 static tree
1735 build_debug_ref_for_model (location_t loc, tree base, HOST_WIDE_INT offset,
1736                            struct access *model)
1737 {
1738   HOST_WIDE_INT base_offset;
1739   tree off;
1740
1741   if (TREE_CODE (model->expr) == COMPONENT_REF
1742       && DECL_BIT_FIELD (TREE_OPERAND (model->expr, 1)))
1743     return NULL_TREE;
1744
1745   base = get_addr_base_and_unit_offset (base, &base_offset);
1746   if (!base)
1747     return NULL_TREE;
1748   if (TREE_CODE (base) == MEM_REF)
1749     {
1750       off = build_int_cst (TREE_TYPE (TREE_OPERAND (base, 1)),
1751                            base_offset + offset / BITS_PER_UNIT);
1752       off = int_const_binop (PLUS_EXPR, TREE_OPERAND (base, 1), off);
1753       base = unshare_expr (TREE_OPERAND (base, 0));
1754     }
1755   else
1756     {
1757       off = build_int_cst (reference_alias_ptr_type (base),
1758                            base_offset + offset / BITS_PER_UNIT);
1759       base = build_fold_addr_expr (unshare_expr (base));
1760     }
1761
1762   return fold_build2_loc (loc, MEM_REF, model->type, base, off);
1763 }
1764
1765 /* Construct a memory reference consisting of component_refs and array_refs to
1766    a part of an aggregate *RES (which is of type TYPE).  The requested part
1767    should have type EXP_TYPE at be the given OFFSET.  This function might not
1768    succeed, it returns true when it does and only then *RES points to something
1769    meaningful.  This function should be used only to build expressions that we
1770    might need to present to user (e.g. in warnings).  In all other situations,
1771    build_ref_for_model or build_ref_for_offset should be used instead.  */
1772
1773 static bool
1774 build_user_friendly_ref_for_offset (tree *res, tree type, HOST_WIDE_INT offset,
1775                                     tree exp_type)
1776 {
1777   while (1)
1778     {
1779       tree fld;
1780       tree tr_size, index, minidx;
1781       HOST_WIDE_INT el_size;
1782
1783       if (offset == 0 && exp_type
1784           && types_compatible_p (exp_type, type))
1785         return true;
1786
1787       switch (TREE_CODE (type))
1788         {
1789         case UNION_TYPE:
1790         case QUAL_UNION_TYPE:
1791         case RECORD_TYPE:
1792           for (fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld))
1793             {
1794               HOST_WIDE_INT pos, size;
1795               tree tr_pos, expr, *expr_ptr;
1796
1797               if (TREE_CODE (fld) != FIELD_DECL)
1798                 continue;
1799
1800               tr_pos = bit_position (fld);
1801               if (!tr_pos || !tree_fits_uhwi_p (tr_pos))
1802                 continue;
1803               pos = tree_to_uhwi (tr_pos);
1804               gcc_assert (TREE_CODE (type) == RECORD_TYPE || pos == 0);
1805               tr_size = DECL_SIZE (fld);
1806               if (!tr_size || !tree_fits_uhwi_p (tr_size))
1807                 continue;
1808               size = tree_to_uhwi (tr_size);
1809               if (size == 0)
1810                 {
1811                   if (pos != offset)
1812                     continue;
1813                 }
1814               else if (pos > offset || (pos + size) <= offset)
1815                 continue;
1816
1817               expr = build3 (COMPONENT_REF, TREE_TYPE (fld), *res, fld,
1818                              NULL_TREE);
1819               expr_ptr = &expr;
1820               if (build_user_friendly_ref_for_offset (expr_ptr, TREE_TYPE (fld),
1821                                                       offset - pos, exp_type))
1822                 {
1823                   *res = expr;
1824                   return true;
1825                 }
1826             }
1827           return false;
1828
1829         case ARRAY_TYPE:
1830           tr_size = TYPE_SIZE (TREE_TYPE (type));
1831           if (!tr_size || !tree_fits_uhwi_p (tr_size))
1832             return false;
1833           el_size = tree_to_uhwi (tr_size);
1834
1835           minidx = TYPE_MIN_VALUE (TYPE_DOMAIN (type));
1836           if (TREE_CODE (minidx) != INTEGER_CST || el_size == 0)
1837             return false;
1838           index = build_int_cst (TYPE_DOMAIN (type), offset / el_size);
1839           if (!integer_zerop (minidx))
1840             index = int_const_binop (PLUS_EXPR, index, minidx);
1841           *res = build4 (ARRAY_REF, TREE_TYPE (type), *res, index,
1842                          NULL_TREE, NULL_TREE);
1843           offset = offset % el_size;
1844           type = TREE_TYPE (type);
1845           break;
1846
1847         default:
1848           if (offset != 0)
1849             return false;
1850
1851           if (exp_type)
1852             return false;
1853           else
1854             return true;
1855         }
1856     }
1857 }
1858
1859 /* Return true iff TYPE is stdarg va_list type.  */
1860
1861 static inline bool
1862 is_va_list_type (tree type)
1863 {
1864   return TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (va_list_type_node);
1865 }
1866
1867 /* Print message to dump file why a variable was rejected. */
1868
1869 static void
1870 reject (tree var, const char *msg)
1871 {
1872   if (dump_file && (dump_flags & TDF_DETAILS))
1873     {
1874       fprintf (dump_file, "Rejected (%d): %s: ", DECL_UID (var), msg);
1875       print_generic_expr (dump_file, var, 0);
1876       fprintf (dump_file, "\n");
1877     }
1878 }
1879
1880 /* Return true if VAR is a candidate for SRA.  */
1881
1882 static bool
1883 maybe_add_sra_candidate (tree var)
1884 {
1885   tree type = TREE_TYPE (var);
1886   const char *msg;
1887   tree_node **slot;
1888
1889   if (!AGGREGATE_TYPE_P (type))
1890     {
1891       reject (var, "not aggregate");
1892       return false;
1893     }
1894   /* Allow constant-pool entries (that "need to live in memory")
1895      unless we are doing IPA SRA.  */
1896   if (needs_to_live_in_memory (var)
1897       && (sra_mode == SRA_MODE_EARLY_IPA || !constant_decl_p (var)))
1898     {
1899       reject (var, "needs to live in memory");
1900       return false;
1901     }
1902   if (TREE_THIS_VOLATILE (var))
1903     {
1904       reject (var, "is volatile");
1905       return false;
1906     }
1907   if (!COMPLETE_TYPE_P (type))
1908     {
1909       reject (var, "has incomplete type");
1910       return false;
1911     }
1912   if (!tree_fits_uhwi_p (TYPE_SIZE (type)))
1913     {
1914       reject (var, "type size not fixed");
1915       return false;
1916     }
1917   if (tree_to_uhwi (TYPE_SIZE (type)) == 0)
1918     {
1919       reject (var, "type size is zero");
1920       return false;
1921     }
1922   if (type_internals_preclude_sra_p (type, &msg))
1923     {
1924       reject (var, msg);
1925       return false;
1926     }
1927   if (/* Fix for PR 41089.  tree-stdarg.c needs to have va_lists intact but
1928          we also want to schedule it rather late.  Thus we ignore it in
1929          the early pass. */
1930       (sra_mode == SRA_MODE_EARLY_INTRA
1931        && is_va_list_type (type)))
1932     {
1933       reject (var, "is va_list");
1934       return false;
1935     }
1936
1937   bitmap_set_bit (candidate_bitmap, DECL_UID (var));
1938   slot = candidates->find_slot_with_hash (var, DECL_UID (var), INSERT);
1939   *slot = var;
1940
1941   if (dump_file && (dump_flags & TDF_DETAILS))
1942     {
1943       fprintf (dump_file, "Candidate (%d): ", DECL_UID (var));
1944       print_generic_expr (dump_file, var, 0);
1945       fprintf (dump_file, "\n");
1946     }
1947
1948   return true;
1949 }
1950
1951 /* The very first phase of intraprocedural SRA.  It marks in candidate_bitmap
1952    those with type which is suitable for scalarization.  */
1953
1954 static bool
1955 find_var_candidates (void)
1956 {
1957   tree var, parm;
1958   unsigned int i;
1959   bool ret = false;
1960
1961   for (parm = DECL_ARGUMENTS (current_function_decl);
1962        parm;
1963        parm = DECL_CHAIN (parm))
1964     ret |= maybe_add_sra_candidate (parm);
1965
1966   FOR_EACH_LOCAL_DECL (cfun, i, var)
1967     {
1968       if (!VAR_P (var))
1969         continue;
1970
1971       ret |= maybe_add_sra_candidate (var);
1972     }
1973
1974   return ret;
1975 }
1976
1977 /* Sort all accesses for the given variable, check for partial overlaps and
1978    return NULL if there are any.  If there are none, pick a representative for
1979    each combination of offset and size and create a linked list out of them.
1980    Return the pointer to the first representative and make sure it is the first
1981    one in the vector of accesses.  */
1982
1983 static struct access *
1984 sort_and_splice_var_accesses (tree var)
1985 {
1986   int i, j, access_count;
1987   struct access *res, **prev_acc_ptr = &res;
1988   vec<access_p> *access_vec;
1989   bool first = true;
1990   HOST_WIDE_INT low = -1, high = 0;
1991
1992   access_vec = get_base_access_vector (var);
1993   if (!access_vec)
1994     return NULL;
1995   access_count = access_vec->length ();
1996
1997   /* Sort by <OFFSET, SIZE>.  */
1998   access_vec->qsort (compare_access_positions);
1999
2000   i = 0;
2001   while (i < access_count)
2002     {
2003       struct access *access = (*access_vec)[i];
2004       bool grp_write = access->write;
2005       bool grp_read = !access->write;
2006       bool grp_scalar_write = access->write
2007         && is_gimple_reg_type (access->type);
2008       bool grp_scalar_read = !access->write
2009         && is_gimple_reg_type (access->type);
2010       bool grp_assignment_read = access->grp_assignment_read;
2011       bool grp_assignment_write = access->grp_assignment_write;
2012       bool multiple_scalar_reads = false;
2013       bool total_scalarization = access->grp_total_scalarization;
2014       bool grp_partial_lhs = access->grp_partial_lhs;
2015       bool first_scalar = is_gimple_reg_type (access->type);
2016       bool unscalarizable_region = access->grp_unscalarizable_region;
2017
2018       if (first || access->offset >= high)
2019         {
2020           first = false;
2021           low = access->offset;
2022           high = access->offset + access->size;
2023         }
2024       else if (access->offset > low && access->offset + access->size > high)
2025         return NULL;
2026       else
2027         gcc_assert (access->offset >= low
2028                     && access->offset + access->size <= high);
2029
2030       j = i + 1;
2031       while (j < access_count)
2032         {
2033           struct access *ac2 = (*access_vec)[j];
2034           if (ac2->offset != access->offset || ac2->size != access->size)
2035             break;
2036           if (ac2->write)
2037             {
2038               grp_write = true;
2039               grp_scalar_write = (grp_scalar_write
2040                                   || is_gimple_reg_type (ac2->type));
2041             }
2042           else
2043             {
2044               grp_read = true;
2045               if (is_gimple_reg_type (ac2->type))
2046                 {
2047                   if (grp_scalar_read)
2048                     multiple_scalar_reads = true;
2049                   else
2050                     grp_scalar_read = true;
2051                 }
2052             }
2053           grp_assignment_read |= ac2->grp_assignment_read;
2054           grp_assignment_write |= ac2->grp_assignment_write;
2055           grp_partial_lhs |= ac2->grp_partial_lhs;
2056           unscalarizable_region |= ac2->grp_unscalarizable_region;
2057           total_scalarization |= ac2->grp_total_scalarization;
2058           relink_to_new_repr (access, ac2);
2059
2060           /* If there are both aggregate-type and scalar-type accesses with
2061              this combination of size and offset, the comparison function
2062              should have put the scalars first.  */
2063           gcc_assert (first_scalar || !is_gimple_reg_type (ac2->type));
2064           ac2->group_representative = access;
2065           j++;
2066         }
2067
2068       i = j;
2069
2070       access->group_representative = access;
2071       access->grp_write = grp_write;
2072       access->grp_read = grp_read;
2073       access->grp_scalar_read = grp_scalar_read;
2074       access->grp_scalar_write = grp_scalar_write;
2075       access->grp_assignment_read = grp_assignment_read;
2076       access->grp_assignment_write = grp_assignment_write;
2077       access->grp_hint = total_scalarization
2078         || (multiple_scalar_reads && !constant_decl_p (var));
2079       access->grp_total_scalarization = total_scalarization;
2080       access->grp_partial_lhs = grp_partial_lhs;
2081       access->grp_unscalarizable_region = unscalarizable_region;
2082       if (access->first_link)
2083         add_access_to_work_queue (access);
2084
2085       *prev_acc_ptr = access;
2086       prev_acc_ptr = &access->next_grp;
2087     }
2088
2089   gcc_assert (res == (*access_vec)[0]);
2090   return res;
2091 }
2092
2093 /* Create a variable for the given ACCESS which determines the type, name and a
2094    few other properties.  Return the variable declaration and store it also to
2095    ACCESS->replacement.  */
2096
2097 static tree
2098 create_access_replacement (struct access *access)
2099 {
2100   tree repl;
2101
2102   if (access->grp_to_be_debug_replaced)
2103     {
2104       repl = create_tmp_var_raw (access->type);
2105       DECL_CONTEXT (repl) = current_function_decl;
2106     }
2107   else
2108     /* Drop any special alignment on the type if it's not on the main
2109        variant.  This avoids issues with weirdo ABIs like AAPCS.  */
2110     repl = create_tmp_var (build_qualified_type
2111                              (TYPE_MAIN_VARIANT (access->type),
2112                               TYPE_QUALS (access->type)), "SR");
2113   if (TREE_CODE (access->type) == COMPLEX_TYPE
2114       || TREE_CODE (access->type) == VECTOR_TYPE)
2115     {
2116       if (!access->grp_partial_lhs)
2117         DECL_GIMPLE_REG_P (repl) = 1;
2118     }
2119   else if (access->grp_partial_lhs
2120            && is_gimple_reg_type (access->type))
2121     TREE_ADDRESSABLE (repl) = 1;
2122
2123   DECL_SOURCE_LOCATION (repl) = DECL_SOURCE_LOCATION (access->base);
2124   DECL_ARTIFICIAL (repl) = 1;
2125   DECL_IGNORED_P (repl) = DECL_IGNORED_P (access->base);
2126
2127   if (DECL_NAME (access->base)
2128       && !DECL_IGNORED_P (access->base)
2129       && !DECL_ARTIFICIAL (access->base))
2130     {
2131       char *pretty_name = make_fancy_name (access->expr);
2132       tree debug_expr = unshare_expr_without_location (access->expr), d;
2133       bool fail = false;
2134
2135       DECL_NAME (repl) = get_identifier (pretty_name);
2136       DECL_NAMELESS (repl) = 1;
2137       obstack_free (&name_obstack, pretty_name);
2138
2139       /* Get rid of any SSA_NAMEs embedded in debug_expr,
2140          as DECL_DEBUG_EXPR isn't considered when looking for still
2141          used SSA_NAMEs and thus they could be freed.  All debug info
2142          generation cares is whether something is constant or variable
2143          and that get_ref_base_and_extent works properly on the
2144          expression.  It cannot handle accesses at a non-constant offset
2145          though, so just give up in those cases.  */
2146       for (d = debug_expr;
2147            !fail && (handled_component_p (d) || TREE_CODE (d) == MEM_REF);
2148            d = TREE_OPERAND (d, 0))
2149         switch (TREE_CODE (d))
2150           {
2151           case ARRAY_REF:
2152           case ARRAY_RANGE_REF:
2153             if (TREE_OPERAND (d, 1)
2154                 && TREE_CODE (TREE_OPERAND (d, 1)) != INTEGER_CST)
2155               fail = true;
2156             if (TREE_OPERAND (d, 3)
2157                 && TREE_CODE (TREE_OPERAND (d, 3)) != INTEGER_CST)
2158               fail = true;
2159             /* FALLTHRU */
2160           case COMPONENT_REF:
2161             if (TREE_OPERAND (d, 2)
2162                 && TREE_CODE (TREE_OPERAND (d, 2)) != INTEGER_CST)
2163               fail = true;
2164             break;
2165           case MEM_REF:
2166             if (TREE_CODE (TREE_OPERAND (d, 0)) != ADDR_EXPR)
2167               fail = true;
2168             else
2169               d = TREE_OPERAND (d, 0);
2170             break;
2171           default:
2172             break;
2173           }
2174       if (!fail)
2175         {
2176           SET_DECL_DEBUG_EXPR (repl, debug_expr);
2177           DECL_HAS_DEBUG_EXPR_P (repl) = 1;
2178         }
2179       if (access->grp_no_warning)
2180         TREE_NO_WARNING (repl) = 1;
2181       else
2182         TREE_NO_WARNING (repl) = TREE_NO_WARNING (access->base);
2183     }
2184   else
2185     TREE_NO_WARNING (repl) = 1;
2186
2187   if (dump_file)
2188     {
2189       if (access->grp_to_be_debug_replaced)
2190         {
2191           fprintf (dump_file, "Created a debug-only replacement for ");
2192           print_generic_expr (dump_file, access->base, 0);
2193           fprintf (dump_file, " offset: %u, size: %u\n",
2194                    (unsigned) access->offset, (unsigned) access->size);
2195         }
2196       else
2197         {
2198           fprintf (dump_file, "Created a replacement for ");
2199           print_generic_expr (dump_file, access->base, 0);
2200           fprintf (dump_file, " offset: %u, size: %u: ",
2201                    (unsigned) access->offset, (unsigned) access->size);
2202           print_generic_expr (dump_file, repl, 0);
2203           fprintf (dump_file, "\n");
2204         }
2205     }
2206   sra_stats.replacements++;
2207
2208   return repl;
2209 }
2210
2211 /* Return ACCESS scalar replacement, which must exist.  */
2212
2213 static inline tree
2214 get_access_replacement (struct access *access)
2215 {
2216   gcc_checking_assert (access->replacement_decl);
2217   return access->replacement_decl;
2218 }
2219
2220
2221 /* Build a subtree of accesses rooted in *ACCESS, and move the pointer in the
2222    linked list along the way.  Stop when *ACCESS is NULL or the access pointed
2223    to it is not "within" the root.  Return false iff some accesses partially
2224    overlap.  */
2225
2226 static bool
2227 build_access_subtree (struct access **access)
2228 {
2229   struct access *root = *access, *last_child = NULL;
2230   HOST_WIDE_INT limit = root->offset + root->size;
2231
2232   *access = (*access)->next_grp;
2233   while  (*access && (*access)->offset + (*access)->size <= limit)
2234     {
2235       if (!last_child)
2236         root->first_child = *access;
2237       else
2238         last_child->next_sibling = *access;
2239       last_child = *access;
2240
2241       if (!build_access_subtree (access))
2242         return false;
2243     }
2244
2245   if (*access && (*access)->offset < limit)
2246     return false;
2247
2248   return true;
2249 }
2250
2251 /* Build a tree of access representatives, ACCESS is the pointer to the first
2252    one, others are linked in a list by the next_grp field.  Return false iff
2253    some accesses partially overlap.  */
2254
2255 static bool
2256 build_access_trees (struct access *access)
2257 {
2258   while (access)
2259     {
2260       struct access *root = access;
2261
2262       if (!build_access_subtree (&access))
2263         return false;
2264       root->next_grp = access;
2265     }
2266   return true;
2267 }
2268
2269 /* Return true if expr contains some ARRAY_REFs into a variable bounded
2270    array.  */
2271
2272 static bool
2273 expr_with_var_bounded_array_refs_p (tree expr)
2274 {
2275   while (handled_component_p (expr))
2276     {
2277       if (TREE_CODE (expr) == ARRAY_REF
2278           && !tree_fits_shwi_p (array_ref_low_bound (expr)))
2279         return true;
2280       expr = TREE_OPERAND (expr, 0);
2281     }
2282   return false;
2283 }
2284
2285 /* Analyze the subtree of accesses rooted in ROOT, scheduling replacements when
2286    both seeming beneficial and when ALLOW_REPLACEMENTS allows it.  Also set all
2287    sorts of access flags appropriately along the way, notably always set
2288    grp_read and grp_assign_read according to MARK_READ and grp_write when
2289    MARK_WRITE is true.
2290
2291    Creating a replacement for a scalar access is considered beneficial if its
2292    grp_hint is set (this means we are either attempting total scalarization or
2293    there is more than one direct read access) or according to the following
2294    table:
2295
2296    Access written to through a scalar type (once or more times)
2297    |
2298    |    Written to in an assignment statement
2299    |    |
2300    |    |       Access read as scalar _once_
2301    |    |       |
2302    |    |       |       Read in an assignment statement
2303    |    |       |       |
2304    |    |       |       |       Scalarize       Comment
2305 -----------------------------------------------------------------------------
2306    0    0       0       0                       No access for the scalar
2307    0    0       0       1                       No access for the scalar
2308    0    0       1       0       No              Single read - won't help
2309    0    0       1       1       No              The same case
2310    0    1       0       0                       No access for the scalar
2311    0    1       0       1                       No access for the scalar
2312    0    1       1       0       Yes             s = *g; return s.i;
2313    0    1       1       1       Yes             The same case as above
2314    1    0       0       0       No              Won't help
2315    1    0       0       1       Yes             s.i = 1; *g = s;
2316    1    0       1       0       Yes             s.i = 5; g = s.i;
2317    1    0       1       1       Yes             The same case as above
2318    1    1       0       0       No              Won't help.
2319    1    1       0       1       Yes             s.i = 1; *g = s;
2320    1    1       1       0       Yes             s = *g; return s.i;
2321    1    1       1       1       Yes             Any of the above yeses  */
2322
2323 static bool
2324 analyze_access_subtree (struct access *root, struct access *parent,
2325                         bool allow_replacements)
2326 {
2327   struct access *child;
2328   HOST_WIDE_INT limit = root->offset + root->size;
2329   HOST_WIDE_INT covered_to = root->offset;
2330   bool scalar = is_gimple_reg_type (root->type);
2331   bool hole = false, sth_created = false;
2332
2333   if (parent)
2334     {
2335       if (parent->grp_read)
2336         root->grp_read = 1;
2337       if (parent->grp_assignment_read)
2338         root->grp_assignment_read = 1;
2339       if (parent->grp_write)
2340         root->grp_write = 1;
2341       if (parent->grp_assignment_write)
2342         root->grp_assignment_write = 1;
2343       if (parent->grp_total_scalarization)
2344         root->grp_total_scalarization = 1;
2345     }
2346
2347   if (root->grp_unscalarizable_region)
2348     allow_replacements = false;
2349
2350   if (allow_replacements && expr_with_var_bounded_array_refs_p (root->expr))
2351     allow_replacements = false;
2352
2353   for (child = root->first_child; child; child = child->next_sibling)
2354     {
2355       hole |= covered_to < child->offset;
2356       sth_created |= analyze_access_subtree (child, root,
2357                                              allow_replacements && !scalar);
2358
2359       root->grp_unscalarized_data |= child->grp_unscalarized_data;
2360       root->grp_total_scalarization &= child->grp_total_scalarization;
2361       if (child->grp_covered)
2362         covered_to += child->size;
2363       else
2364         hole = true;
2365     }
2366
2367   if (allow_replacements && scalar && !root->first_child
2368       && (root->grp_hint
2369           || ((root->grp_scalar_read || root->grp_assignment_read)
2370               && (root->grp_scalar_write || root->grp_assignment_write))))
2371     {
2372       /* Always create access replacements that cover the whole access.
2373          For integral types this means the precision has to match.
2374          Avoid assumptions based on the integral type kind, too.  */
2375       if (INTEGRAL_TYPE_P (root->type)
2376           && (TREE_CODE (root->type) != INTEGER_TYPE
2377               || TYPE_PRECISION (root->type) != root->size)
2378           /* But leave bitfield accesses alone.  */
2379           && (TREE_CODE (root->expr) != COMPONENT_REF
2380               || !DECL_BIT_FIELD (TREE_OPERAND (root->expr, 1))))
2381         {
2382           tree rt = root->type;
2383           gcc_assert ((root->offset % BITS_PER_UNIT) == 0
2384                       && (root->size % BITS_PER_UNIT) == 0);
2385           root->type = build_nonstandard_integer_type (root->size,
2386                                                        TYPE_UNSIGNED (rt));
2387           root->expr = build_ref_for_offset (UNKNOWN_LOCATION, root->base,
2388                                              root->offset, root->reverse,
2389                                              root->type, NULL, false);
2390
2391           if (dump_file && (dump_flags & TDF_DETAILS))
2392             {
2393               fprintf (dump_file, "Changing the type of a replacement for ");
2394               print_generic_expr (dump_file, root->base, 0);
2395               fprintf (dump_file, " offset: %u, size: %u ",
2396                        (unsigned) root->offset, (unsigned) root->size);
2397               fprintf (dump_file, " to an integer.\n");
2398             }
2399         }
2400
2401       root->grp_to_be_replaced = 1;
2402       root->replacement_decl = create_access_replacement (root);
2403       sth_created = true;
2404       hole = false;
2405     }
2406   else
2407     {
2408       if (allow_replacements
2409           && scalar && !root->first_child
2410           && (root->grp_scalar_write || root->grp_assignment_write)
2411           && !bitmap_bit_p (cannot_scalarize_away_bitmap,
2412                             DECL_UID (root->base)))
2413         {
2414           gcc_checking_assert (!root->grp_scalar_read
2415                                && !root->grp_assignment_read);
2416           sth_created = true;
2417           if (MAY_HAVE_DEBUG_STMTS)
2418             {
2419               root->grp_to_be_debug_replaced = 1;
2420               root->replacement_decl = create_access_replacement (root);
2421             }
2422         }
2423
2424       if (covered_to < limit)
2425         hole = true;
2426       if (scalar || !allow_replacements)
2427         root->grp_total_scalarization = 0;
2428     }
2429
2430   if (!hole || root->grp_total_scalarization)
2431     root->grp_covered = 1;
2432   else if (root->grp_write || TREE_CODE (root->base) == PARM_DECL
2433            || constant_decl_p (root->base))
2434     root->grp_unscalarized_data = 1; /* not covered and written to */
2435   return sth_created;
2436 }
2437
2438 /* Analyze all access trees linked by next_grp by the means of
2439    analyze_access_subtree.  */
2440 static bool
2441 analyze_access_trees (struct access *access)
2442 {
2443   bool ret = false;
2444
2445   while (access)
2446     {
2447       if (analyze_access_subtree (access, NULL, true))
2448         ret = true;
2449       access = access->next_grp;
2450     }
2451
2452   return ret;
2453 }
2454
2455 /* Return true iff a potential new child of LACC at offset OFFSET and with size
2456    SIZE would conflict with an already existing one.  If exactly such a child
2457    already exists in LACC, store a pointer to it in EXACT_MATCH.  */
2458
2459 static bool
2460 child_would_conflict_in_lacc (struct access *lacc, HOST_WIDE_INT norm_offset,
2461                               HOST_WIDE_INT size, struct access **exact_match)
2462 {
2463   struct access *child;
2464
2465   for (child = lacc->first_child; child; child = child->next_sibling)
2466     {
2467       if (child->offset == norm_offset && child->size == size)
2468         {
2469           *exact_match = child;
2470           return true;
2471         }
2472
2473       if (child->offset < norm_offset + size
2474           && child->offset + child->size > norm_offset)
2475         return true;
2476     }
2477
2478   return false;
2479 }
2480
2481 /* Create a new child access of PARENT, with all properties just like MODEL
2482    except for its offset and with its grp_write false and grp_read true.
2483    Return the new access or NULL if it cannot be created.  Note that this access
2484    is created long after all splicing and sorting, it's not located in any
2485    access vector and is automatically a representative of its group.  */
2486
2487 static struct access *
2488 create_artificial_child_access (struct access *parent, struct access *model,
2489                                 HOST_WIDE_INT new_offset)
2490 {
2491   struct access **child;
2492   tree expr = parent->base;
2493
2494   gcc_assert (!model->grp_unscalarizable_region);
2495
2496   struct access *access = access_pool.allocate ();
2497   memset (access, 0, sizeof (struct access));
2498   if (!build_user_friendly_ref_for_offset (&expr, TREE_TYPE (expr), new_offset,
2499                                            model->type))
2500     {
2501       access->grp_no_warning = true;
2502       expr = build_ref_for_model (EXPR_LOCATION (parent->base), parent->base,
2503                                   new_offset, model, NULL, false);
2504     }
2505
2506   access->base = parent->base;
2507   access->expr = expr;
2508   access->offset = new_offset;
2509   access->size = model->size;
2510   access->type = model->type;
2511   access->grp_write = true;
2512   access->grp_read = false;
2513   access->reverse = model->reverse;
2514
2515   child = &parent->first_child;
2516   while (*child && (*child)->offset < new_offset)
2517     child = &(*child)->next_sibling;
2518
2519   access->next_sibling = *child;
2520   *child = access;
2521
2522   return access;
2523 }
2524
2525
2526 /* Propagate all subaccesses of RACC across an assignment link to LACC. Return
2527    true if any new subaccess was created.  Additionally, if RACC is a scalar
2528    access but LACC is not, change the type of the latter, if possible.  */
2529
2530 static bool
2531 propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
2532 {
2533   struct access *rchild;
2534   HOST_WIDE_INT norm_delta = lacc->offset - racc->offset;
2535   bool ret = false;
2536
2537   if (is_gimple_reg_type (lacc->type)
2538       || lacc->grp_unscalarizable_region
2539       || racc->grp_unscalarizable_region)
2540     return false;
2541
2542   if (is_gimple_reg_type (racc->type))
2543     {
2544       if (!lacc->first_child && !racc->first_child)
2545         {
2546           tree t = lacc->base;
2547
2548           lacc->type = racc->type;
2549           if (build_user_friendly_ref_for_offset (&t, TREE_TYPE (t),
2550                                                   lacc->offset, racc->type))
2551             lacc->expr = t;
2552           else
2553             {
2554               lacc->expr = build_ref_for_model (EXPR_LOCATION (lacc->base),
2555                                                 lacc->base, lacc->offset,
2556                                                 racc, NULL, false);
2557               lacc->grp_no_warning = true;
2558             }
2559         }
2560       return false;
2561     }
2562
2563   for (rchild = racc->first_child; rchild; rchild = rchild->next_sibling)
2564     {
2565       struct access *new_acc = NULL;
2566       HOST_WIDE_INT norm_offset = rchild->offset + norm_delta;
2567
2568       if (rchild->grp_unscalarizable_region)
2569         continue;
2570
2571       if (child_would_conflict_in_lacc (lacc, norm_offset, rchild->size,
2572                                         &new_acc))
2573         {
2574           if (new_acc)
2575             {
2576               rchild->grp_hint = 1;
2577               new_acc->grp_hint |= new_acc->grp_read;
2578               if (rchild->first_child)
2579                 ret |= propagate_subaccesses_across_link (new_acc, rchild);
2580             }
2581           continue;
2582         }
2583
2584       rchild->grp_hint = 1;
2585       new_acc = create_artificial_child_access (lacc, rchild, norm_offset);
2586       if (new_acc)
2587         {
2588           ret = true;
2589           if (racc->first_child)
2590             propagate_subaccesses_across_link (new_acc, rchild);
2591         }
2592     }
2593
2594   return ret;
2595 }
2596
2597 /* Propagate all subaccesses across assignment links.  */
2598
2599 static void
2600 propagate_all_subaccesses (void)
2601 {
2602   while (work_queue_head)
2603     {
2604       struct access *racc = pop_access_from_work_queue ();
2605       struct assign_link *link;
2606
2607       gcc_assert (racc->first_link);
2608
2609       for (link = racc->first_link; link; link = link->next)
2610         {
2611           struct access *lacc = link->lacc;
2612
2613           if (!bitmap_bit_p (candidate_bitmap, DECL_UID (lacc->base)))
2614             continue;
2615           lacc = lacc->group_representative;
2616           if (propagate_subaccesses_across_link (lacc, racc)
2617               && lacc->first_link)
2618             add_access_to_work_queue (lacc);
2619         }
2620     }
2621 }
2622
2623 /* Go through all accesses collected throughout the (intraprocedural) analysis
2624    stage, exclude overlapping ones, identify representatives and build trees
2625    out of them, making decisions about scalarization on the way.  Return true
2626    iff there are any to-be-scalarized variables after this stage. */
2627
2628 static bool
2629 analyze_all_variable_accesses (void)
2630 {
2631   int res = 0;
2632   bitmap tmp = BITMAP_ALLOC (NULL);
2633   bitmap_iterator bi;
2634   unsigned i;
2635   bool optimize_speed_p = !optimize_function_for_size_p (cfun);
2636
2637   enum compiler_param param = optimize_speed_p
2638                         ? PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED
2639                         : PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE;
2640
2641   /* If the user didn't set PARAM_SRA_MAX_SCALARIZATION_SIZE_<...>,
2642      fall back to a target default.  */
2643   unsigned HOST_WIDE_INT max_scalarization_size
2644     = global_options_set.x_param_values[param]
2645       ? PARAM_VALUE (param)
2646       : get_move_ratio (optimize_speed_p) * UNITS_PER_WORD;
2647
2648   max_scalarization_size *= BITS_PER_UNIT;
2649
2650   EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
2651     if (bitmap_bit_p (should_scalarize_away_bitmap, i)
2652         && !bitmap_bit_p (cannot_scalarize_away_bitmap, i))
2653       {
2654         tree var = candidate (i);
2655
2656         if (VAR_P (var) && scalarizable_type_p (TREE_TYPE (var)))
2657           {
2658             if (tree_to_uhwi (TYPE_SIZE (TREE_TYPE (var)))
2659                 <= max_scalarization_size)
2660               {
2661                 create_total_scalarization_access (var);
2662                 completely_scalarize (var, TREE_TYPE (var), 0, var);
2663                 if (dump_file && (dump_flags & TDF_DETAILS))
2664                   {
2665                     fprintf (dump_file, "Will attempt to totally scalarize ");
2666                     print_generic_expr (dump_file, var, 0);
2667                     fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2668                   }
2669               }
2670             else if (dump_file && (dump_flags & TDF_DETAILS))
2671               {
2672                 fprintf (dump_file, "Too big to totally scalarize: ");
2673                 print_generic_expr (dump_file, var, 0);
2674                 fprintf (dump_file, " (UID: %u)\n", DECL_UID (var));
2675               }
2676           }
2677       }
2678
2679   bitmap_copy (tmp, candidate_bitmap);
2680   EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2681     {
2682       tree var = candidate (i);
2683       struct access *access;
2684
2685       access = sort_and_splice_var_accesses (var);
2686       if (!access || !build_access_trees (access))
2687         disqualify_candidate (var,
2688                               "No or inhibitingly overlapping accesses.");
2689     }
2690
2691   propagate_all_subaccesses ();
2692
2693   bitmap_copy (tmp, candidate_bitmap);
2694   EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2695     {
2696       tree var = candidate (i);
2697       struct access *access = get_first_repr_for_decl (var);
2698
2699       if (analyze_access_trees (access))
2700         {
2701           res++;
2702           if (dump_file && (dump_flags & TDF_DETAILS))
2703             {
2704               fprintf (dump_file, "\nAccess trees for ");
2705               print_generic_expr (dump_file, var, 0);
2706               fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2707               dump_access_tree (dump_file, access);
2708               fprintf (dump_file, "\n");
2709             }
2710         }
2711       else
2712         disqualify_candidate (var, "No scalar replacements to be created.");
2713     }
2714
2715   BITMAP_FREE (tmp);
2716
2717   if (res)
2718     {
2719       statistics_counter_event (cfun, "Scalarized aggregates", res);
2720       return true;
2721     }
2722   else
2723     return false;
2724 }
2725
2726 /* Generate statements copying scalar replacements of accesses within a subtree
2727    into or out of AGG.  ACCESS, all its children, siblings and their children
2728    are to be processed.  AGG is an aggregate type expression (can be a
2729    declaration but does not have to be, it can for example also be a mem_ref or
2730    a series of handled components).  TOP_OFFSET is the offset of the processed
2731    subtree which has to be subtracted from offsets of individual accesses to
2732    get corresponding offsets for AGG.  If CHUNK_SIZE is non-null, copy only
2733    replacements in the interval <start_offset, start_offset + chunk_size>,
2734    otherwise copy all.  GSI is a statement iterator used to place the new
2735    statements.  WRITE should be true when the statements should write from AGG
2736    to the replacement and false if vice versa.  if INSERT_AFTER is true, new
2737    statements will be added after the current statement in GSI, they will be
2738    added before the statement otherwise.  */
2739
2740 static void
2741 generate_subtree_copies (struct access *access, tree agg,
2742                          HOST_WIDE_INT top_offset,
2743                          HOST_WIDE_INT start_offset, HOST_WIDE_INT chunk_size,
2744                          gimple_stmt_iterator *gsi, bool write,
2745                          bool insert_after, location_t loc)
2746 {
2747   /* Never write anything into constant pool decls.  See PR70602.  */
2748   if (!write && constant_decl_p (agg))
2749     return;
2750   do
2751     {
2752       if (chunk_size && access->offset >= start_offset + chunk_size)
2753         return;
2754
2755       if (access->grp_to_be_replaced
2756           && (chunk_size == 0
2757               || access->offset + access->size > start_offset))
2758         {
2759           tree expr, repl = get_access_replacement (access);
2760           gassign *stmt;
2761
2762           expr = build_ref_for_model (loc, agg, access->offset - top_offset,
2763                                       access, gsi, insert_after);
2764
2765           if (write)
2766             {
2767               if (access->grp_partial_lhs)
2768                 expr = force_gimple_operand_gsi (gsi, expr, true, NULL_TREE,
2769                                                  !insert_after,
2770                                                  insert_after ? GSI_NEW_STMT
2771                                                  : GSI_SAME_STMT);
2772               stmt = gimple_build_assign (repl, expr);
2773             }
2774           else
2775             {
2776               TREE_NO_WARNING (repl) = 1;
2777               if (access->grp_partial_lhs)
2778                 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
2779                                                  !insert_after,
2780                                                  insert_after ? GSI_NEW_STMT
2781                                                  : GSI_SAME_STMT);
2782               stmt = gimple_build_assign (expr, repl);
2783             }
2784           gimple_set_location (stmt, loc);
2785
2786           if (insert_after)
2787             gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2788           else
2789             gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2790           update_stmt (stmt);
2791           sra_stats.subtree_copies++;
2792         }
2793       else if (write
2794                && access->grp_to_be_debug_replaced
2795                && (chunk_size == 0
2796                    || access->offset + access->size > start_offset))
2797         {
2798           gdebug *ds;
2799           tree drhs = build_debug_ref_for_model (loc, agg,
2800                                                  access->offset - top_offset,
2801                                                  access);
2802           ds = gimple_build_debug_bind (get_access_replacement (access),
2803                                         drhs, gsi_stmt (*gsi));
2804           if (insert_after)
2805             gsi_insert_after (gsi, ds, GSI_NEW_STMT);
2806           else
2807             gsi_insert_before (gsi, ds, GSI_SAME_STMT);
2808         }
2809
2810       if (access->first_child)
2811         generate_subtree_copies (access->first_child, agg, top_offset,
2812                                  start_offset, chunk_size, gsi,
2813                                  write, insert_after, loc);
2814
2815       access = access->next_sibling;
2816     }
2817   while (access);
2818 }
2819
2820 /* Assign zero to all scalar replacements in an access subtree.  ACCESS is the
2821    root of the subtree to be processed.  GSI is the statement iterator used
2822    for inserting statements which are added after the current statement if
2823    INSERT_AFTER is true or before it otherwise.  */
2824
2825 static void
2826 init_subtree_with_zero (struct access *access, gimple_stmt_iterator *gsi,
2827                         bool insert_after, location_t loc)
2828
2829 {
2830   struct access *child;
2831
2832   if (access->grp_to_be_replaced)
2833     {
2834       gassign *stmt;
2835
2836       stmt = gimple_build_assign (get_access_replacement (access),
2837                                   build_zero_cst (access->type));
2838       if (insert_after)
2839         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2840       else
2841         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2842       update_stmt (stmt);
2843       gimple_set_location (stmt, loc);
2844     }
2845   else if (access->grp_to_be_debug_replaced)
2846     {
2847       gdebug *ds
2848         = gimple_build_debug_bind (get_access_replacement (access),
2849                                    build_zero_cst (access->type),
2850                                    gsi_stmt (*gsi));
2851       if (insert_after)
2852         gsi_insert_after (gsi, ds, GSI_NEW_STMT);
2853       else
2854         gsi_insert_before (gsi, ds, GSI_SAME_STMT);
2855     }
2856
2857   for (child = access->first_child; child; child = child->next_sibling)
2858     init_subtree_with_zero (child, gsi, insert_after, loc);
2859 }
2860
2861 /* Clobber all scalar replacements in an access subtree.  ACCESS is the
2862    root of the subtree to be processed.  GSI is the statement iterator used
2863    for inserting statements which are added after the current statement if
2864    INSERT_AFTER is true or before it otherwise.  */
2865
2866 static void
2867 clobber_subtree (struct access *access, gimple_stmt_iterator *gsi,
2868                 bool insert_after, location_t loc)
2869
2870 {
2871   struct access *child;
2872
2873   if (access->grp_to_be_replaced)
2874     {
2875       tree rep = get_access_replacement (access);
2876       tree clobber = build_constructor (access->type, NULL);
2877       TREE_THIS_VOLATILE (clobber) = 1;
2878       gimple *stmt = gimple_build_assign (rep, clobber);
2879
2880       if (insert_after)
2881         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2882       else
2883         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2884       update_stmt (stmt);
2885       gimple_set_location (stmt, loc);
2886     }
2887
2888   for (child = access->first_child; child; child = child->next_sibling)
2889     clobber_subtree (child, gsi, insert_after, loc);
2890 }
2891
2892 /* Search for an access representative for the given expression EXPR and
2893    return it or NULL if it cannot be found.  */
2894
2895 static struct access *
2896 get_access_for_expr (tree expr)
2897 {
2898   HOST_WIDE_INT offset, size, max_size;
2899   tree base;
2900   bool reverse;
2901
2902   /* FIXME: This should not be necessary but Ada produces V_C_Es with a type of
2903      a different size than the size of its argument and we need the latter
2904      one.  */
2905   if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
2906     expr = TREE_OPERAND (expr, 0);
2907
2908   base = get_ref_base_and_extent (expr, &offset, &size, &max_size, &reverse);
2909   if (max_size == -1 || !DECL_P (base))
2910     return NULL;
2911
2912   if (!bitmap_bit_p (candidate_bitmap, DECL_UID (base)))
2913     return NULL;
2914
2915   return get_var_base_offset_size_access (base, offset, max_size);
2916 }
2917
2918 /* Replace the expression EXPR with a scalar replacement if there is one and
2919    generate other statements to do type conversion or subtree copying if
2920    necessary.  GSI is used to place newly created statements, WRITE is true if
2921    the expression is being written to (it is on a LHS of a statement or output
2922    in an assembly statement).  */
2923
2924 static bool
2925 sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi, bool write)
2926 {
2927   location_t loc;
2928   struct access *access;
2929   tree type, bfr, orig_expr;
2930
2931   if (TREE_CODE (*expr) == BIT_FIELD_REF)
2932     {
2933       bfr = *expr;
2934       expr = &TREE_OPERAND (*expr, 0);
2935     }
2936   else
2937     bfr = NULL_TREE;
2938
2939   if (TREE_CODE (*expr) == REALPART_EXPR || TREE_CODE (*expr) == IMAGPART_EXPR)
2940     expr = &TREE_OPERAND (*expr, 0);
2941   access = get_access_for_expr (*expr);
2942   if (!access)
2943     return false;
2944   type = TREE_TYPE (*expr);
2945   orig_expr = *expr;
2946
2947   loc = gimple_location (gsi_stmt (*gsi));
2948   gimple_stmt_iterator alt_gsi = gsi_none ();
2949   if (write && stmt_ends_bb_p (gsi_stmt (*gsi)))
2950     {
2951       alt_gsi = gsi_start_edge (single_non_eh_succ (gsi_bb (*gsi)));
2952       gsi = &alt_gsi;
2953     }
2954
2955   if (access->grp_to_be_replaced)
2956     {
2957       tree repl = get_access_replacement (access);
2958       /* If we replace a non-register typed access simply use the original
2959          access expression to extract the scalar component afterwards.
2960          This happens if scalarizing a function return value or parameter
2961          like in gcc.c-torture/execute/20041124-1.c, 20050316-1.c and
2962          gcc.c-torture/compile/20011217-1.c.
2963
2964          We also want to use this when accessing a complex or vector which can
2965          be accessed as a different type too, potentially creating a need for
2966          type conversion (see PR42196) and when scalarized unions are involved
2967          in assembler statements (see PR42398).  */
2968       if (!useless_type_conversion_p (type, access->type))
2969         {
2970           tree ref;
2971
2972           ref = build_ref_for_model (loc, orig_expr, 0, access, gsi, false);
2973
2974           if (write)
2975             {
2976               gassign *stmt;
2977
2978               if (access->grp_partial_lhs)
2979                 ref = force_gimple_operand_gsi (gsi, ref, true, NULL_TREE,
2980                                                  false, GSI_NEW_STMT);
2981               stmt = gimple_build_assign (repl, ref);
2982               gimple_set_location (stmt, loc);
2983               gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2984             }
2985           else
2986             {
2987               gassign *stmt;
2988
2989               if (access->grp_partial_lhs)
2990                 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
2991                                                  true, GSI_SAME_STMT);
2992               stmt = gimple_build_assign (ref, repl);
2993               gimple_set_location (stmt, loc);
2994               gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2995             }
2996         }
2997       else
2998         *expr = repl;
2999       sra_stats.exprs++;
3000     }
3001   else if (write && access->grp_to_be_debug_replaced)
3002     {
3003       gdebug *ds = gimple_build_debug_bind (get_access_replacement (access),
3004                                             NULL_TREE,
3005                                             gsi_stmt (*gsi));
3006       gsi_insert_after (gsi, ds, GSI_NEW_STMT);
3007     }
3008
3009   if (access->first_child)
3010     {
3011       HOST_WIDE_INT start_offset, chunk_size;
3012       if (bfr
3013           && tree_fits_uhwi_p (TREE_OPERAND (bfr, 1))
3014           && tree_fits_uhwi_p (TREE_OPERAND (bfr, 2)))
3015         {
3016           chunk_size = tree_to_uhwi (TREE_OPERAND (bfr, 1));
3017           start_offset = access->offset
3018             + tree_to_uhwi (TREE_OPERAND (bfr, 2));
3019         }
3020       else
3021         start_offset = chunk_size = 0;
3022
3023       generate_subtree_copies (access->first_child, orig_expr, access->offset,
3024                                start_offset, chunk_size, gsi, write, write,
3025                                loc);
3026     }
3027   return true;
3028 }
3029
3030 /* Where scalar replacements of the RHS have been written to when a replacement
3031    of a LHS of an assigments cannot be direclty loaded from a replacement of
3032    the RHS. */
3033 enum unscalarized_data_handling { SRA_UDH_NONE,  /* Nothing done so far. */
3034                                   SRA_UDH_RIGHT, /* Data flushed to the RHS. */
3035                                   SRA_UDH_LEFT }; /* Data flushed to the LHS. */
3036
3037 struct subreplacement_assignment_data
3038 {
3039   /* Offset of the access representing the lhs of the assignment.  */
3040   HOST_WIDE_INT left_offset;
3041
3042   /* LHS and RHS of the original assignment.  */
3043   tree assignment_lhs, assignment_rhs;
3044
3045   /* Access representing the rhs of the whole assignment.  */
3046   struct access *top_racc;
3047
3048   /* Stmt iterator used for statement insertions after the original assignment.
3049    It points to the main GSI used to traverse a BB during function body
3050    modification.  */
3051   gimple_stmt_iterator *new_gsi;
3052
3053   /* Stmt iterator used for statement insertions before the original
3054    assignment.  Keeps on pointing to the original statement.  */
3055   gimple_stmt_iterator old_gsi;
3056
3057   /* Location of the assignment.   */
3058   location_t loc;
3059
3060   /* Keeps the information whether we have needed to refresh replacements of
3061    the LHS and from which side of the assignments this takes place.  */
3062   enum unscalarized_data_handling refreshed;
3063 };
3064
3065 /* Store all replacements in the access tree rooted in TOP_RACC either to their
3066    base aggregate if there are unscalarized data or directly to LHS of the
3067    statement that is pointed to by GSI otherwise.  */
3068
3069 static void
3070 handle_unscalarized_data_in_subtree (struct subreplacement_assignment_data *sad)
3071 {
3072   tree src;
3073   if (sad->top_racc->grp_unscalarized_data)
3074     {
3075       src = sad->assignment_rhs;
3076       sad->refreshed = SRA_UDH_RIGHT;
3077     }
3078   else
3079     {
3080       src = sad->assignment_lhs;
3081       sad->refreshed = SRA_UDH_LEFT;
3082     }
3083   generate_subtree_copies (sad->top_racc->first_child, src,
3084                            sad->top_racc->offset, 0, 0,
3085                            &sad->old_gsi, false, false, sad->loc);
3086 }
3087
3088 /* Try to generate statements to load all sub-replacements in an access subtree
3089    formed by children of LACC from scalar replacements in the SAD->top_racc
3090    subtree.  If that is not possible, refresh the SAD->top_racc base aggregate
3091    and load the accesses from it.  */
3092
3093 static void
3094 load_assign_lhs_subreplacements (struct access *lacc,
3095                                  struct subreplacement_assignment_data *sad)
3096 {
3097   for (lacc = lacc->first_child; lacc; lacc = lacc->next_sibling)
3098     {
3099       HOST_WIDE_INT offset;
3100       offset = lacc->offset - sad->left_offset + sad->top_racc->offset;
3101
3102       if (lacc->grp_to_be_replaced)
3103         {
3104           struct access *racc;
3105           gassign *stmt;
3106           tree rhs;
3107
3108           racc = find_access_in_subtree (sad->top_racc, offset, lacc->size);
3109           if (racc && racc->grp_to_be_replaced)
3110             {
3111               rhs = get_access_replacement (racc);
3112               if (!useless_type_conversion_p (lacc->type, racc->type))
3113                 rhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
3114                                        lacc->type, rhs);
3115
3116               if (racc->grp_partial_lhs && lacc->grp_partial_lhs)
3117                 rhs = force_gimple_operand_gsi (&sad->old_gsi, rhs, true,
3118                                                 NULL_TREE, true, GSI_SAME_STMT);
3119             }
3120           else
3121             {
3122               /* No suitable access on the right hand side, need to load from
3123                  the aggregate.  See if we have to update it first... */
3124               if (sad->refreshed == SRA_UDH_NONE)
3125                 handle_unscalarized_data_in_subtree (sad);
3126
3127               if (sad->refreshed == SRA_UDH_LEFT)
3128                 rhs = build_ref_for_model (sad->loc, sad->assignment_lhs,
3129                                            lacc->offset - sad->left_offset,
3130                                            lacc, sad->new_gsi, true);
3131               else
3132                 rhs = build_ref_for_model (sad->loc, sad->assignment_rhs,
3133                                            lacc->offset - sad->left_offset,
3134                                            lacc, sad->new_gsi, true);
3135               if (lacc->grp_partial_lhs)
3136                 rhs = force_gimple_operand_gsi (sad->new_gsi,
3137                                                 rhs, true, NULL_TREE,
3138                                                 false, GSI_NEW_STMT);
3139             }
3140
3141           stmt = gimple_build_assign (get_access_replacement (lacc), rhs);
3142           gsi_insert_after (sad->new_gsi, stmt, GSI_NEW_STMT);
3143           gimple_set_location (stmt, sad->loc);
3144           update_stmt (stmt);
3145           sra_stats.subreplacements++;
3146         }
3147       else
3148         {
3149           if (sad->refreshed == SRA_UDH_NONE
3150               && lacc->grp_read && !lacc->grp_covered)
3151             handle_unscalarized_data_in_subtree (sad);
3152
3153           if (lacc && lacc->grp_to_be_debug_replaced)
3154             {
3155               gdebug *ds;
3156               tree drhs;
3157               struct access *racc = find_access_in_subtree (sad->top_racc,
3158                                                             offset,
3159                                                             lacc->size);
3160
3161               if (racc && racc->grp_to_be_replaced)
3162                 {
3163                   if (racc->grp_write || constant_decl_p (racc->base))
3164                     drhs = get_access_replacement (racc);
3165                   else
3166                     drhs = NULL;
3167                 }
3168               else if (sad->refreshed == SRA_UDH_LEFT)
3169                 drhs = build_debug_ref_for_model (sad->loc, lacc->base,
3170                                                   lacc->offset, lacc);
3171               else if (sad->refreshed == SRA_UDH_RIGHT)
3172                 drhs = build_debug_ref_for_model (sad->loc, sad->top_racc->base,
3173                                                   offset, lacc);
3174               else
3175                 drhs = NULL_TREE;
3176               if (drhs
3177                   && !useless_type_conversion_p (lacc->type, TREE_TYPE (drhs)))
3178                 drhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
3179                                         lacc->type, drhs);
3180               ds = gimple_build_debug_bind (get_access_replacement (lacc),
3181                                             drhs, gsi_stmt (sad->old_gsi));
3182               gsi_insert_after (sad->new_gsi, ds, GSI_NEW_STMT);
3183             }
3184         }
3185
3186       if (lacc->first_child)
3187         load_assign_lhs_subreplacements (lacc, sad);
3188     }
3189 }
3190
3191 /* Result code for SRA assignment modification.  */
3192 enum assignment_mod_result { SRA_AM_NONE,       /* nothing done for the stmt */
3193                              SRA_AM_MODIFIED,  /* stmt changed but not
3194                                                   removed */
3195                              SRA_AM_REMOVED };  /* stmt eliminated */
3196
3197 /* Modify assignments with a CONSTRUCTOR on their RHS.  STMT contains a pointer
3198    to the assignment and GSI is the statement iterator pointing at it.  Returns
3199    the same values as sra_modify_assign.  */
3200
3201 static enum assignment_mod_result
3202 sra_modify_constructor_assign (gimple *stmt, gimple_stmt_iterator *gsi)
3203 {
3204   tree lhs = gimple_assign_lhs (stmt);
3205   struct access *acc = get_access_for_expr (lhs);
3206   if (!acc)
3207     return SRA_AM_NONE;
3208   location_t loc = gimple_location (stmt);
3209
3210   if (gimple_clobber_p (stmt))
3211     {
3212       /* Clobber the replacement variable.  */
3213       clobber_subtree (acc, gsi, !acc->grp_covered, loc);
3214       /* Remove clobbers of fully scalarized variables, they are dead.  */
3215       if (acc->grp_covered)
3216         {
3217           unlink_stmt_vdef (stmt);
3218           gsi_remove (gsi, true);
3219           release_defs (stmt);
3220           return SRA_AM_REMOVED;
3221         }
3222       else
3223         return SRA_AM_MODIFIED;
3224     }
3225
3226   if (CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt)) > 0)
3227     {
3228       /* I have never seen this code path trigger but if it can happen the
3229          following should handle it gracefully.  */
3230       if (access_has_children_p (acc))
3231         generate_subtree_copies (acc->first_child, lhs, acc->offset, 0, 0, gsi,
3232                                  true, true, loc);
3233       return SRA_AM_MODIFIED;
3234     }
3235
3236   if (acc->grp_covered)
3237     {
3238       init_subtree_with_zero (acc, gsi, false, loc);
3239       unlink_stmt_vdef (stmt);
3240       gsi_remove (gsi, true);
3241       release_defs (stmt);
3242       return SRA_AM_REMOVED;
3243     }
3244   else
3245     {
3246       init_subtree_with_zero (acc, gsi, true, loc);
3247       return SRA_AM_MODIFIED;
3248     }
3249 }
3250
3251 /* Create and return a new suitable default definition SSA_NAME for RACC which
3252    is an access describing an uninitialized part of an aggregate that is being
3253    loaded.  */
3254
3255 static tree
3256 get_repl_default_def_ssa_name (struct access *racc)
3257 {
3258   gcc_checking_assert (!racc->grp_to_be_replaced
3259                        && !racc->grp_to_be_debug_replaced);
3260   if (!racc->replacement_decl)
3261     racc->replacement_decl = create_access_replacement (racc);
3262   return get_or_create_ssa_default_def (cfun, racc->replacement_decl);
3263 }
3264
3265 /* Return true if REF has an VIEW_CONVERT_EXPR or a COMPONENT_REF with a
3266    bit-field field declaration somewhere in it.  */
3267
3268 static inline bool
3269 contains_vce_or_bfcref_p (const_tree ref)
3270 {
3271   while (handled_component_p (ref))
3272     {
3273       if (TREE_CODE (ref) == VIEW_CONVERT_EXPR
3274           || (TREE_CODE (ref) == COMPONENT_REF
3275               && DECL_BIT_FIELD (TREE_OPERAND (ref, 1))))
3276         return true;
3277       ref = TREE_OPERAND (ref, 0);
3278     }
3279
3280   return false;
3281 }
3282
3283 /* Examine both sides of the assignment statement pointed to by STMT, replace
3284    them with a scalare replacement if there is one and generate copying of
3285    replacements if scalarized aggregates have been used in the assignment.  GSI
3286    is used to hold generated statements for type conversions and subtree
3287    copying.  */
3288
3289 static enum assignment_mod_result
3290 sra_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi)
3291 {
3292   struct access *lacc, *racc;
3293   tree lhs, rhs;
3294   bool modify_this_stmt = false;
3295   bool force_gimple_rhs = false;
3296   location_t loc;
3297   gimple_stmt_iterator orig_gsi = *gsi;
3298
3299   if (!gimple_assign_single_p (stmt))
3300     return SRA_AM_NONE;
3301   lhs = gimple_assign_lhs (stmt);
3302   rhs = gimple_assign_rhs1 (stmt);
3303
3304   if (TREE_CODE (rhs) == CONSTRUCTOR)
3305     return sra_modify_constructor_assign (stmt, gsi);
3306
3307   if (TREE_CODE (rhs) == REALPART_EXPR || TREE_CODE (lhs) == REALPART_EXPR
3308       || TREE_CODE (rhs) == IMAGPART_EXPR || TREE_CODE (lhs) == IMAGPART_EXPR
3309       || TREE_CODE (rhs) == BIT_FIELD_REF || TREE_CODE (lhs) == BIT_FIELD_REF)
3310     {
3311       modify_this_stmt = sra_modify_expr (gimple_assign_rhs1_ptr (stmt),
3312                                           gsi, false);
3313       modify_this_stmt |= sra_modify_expr (gimple_assign_lhs_ptr (stmt),
3314                                            gsi, true);
3315       return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
3316     }
3317
3318   lacc = get_access_for_expr (lhs);
3319   racc = get_access_for_expr (rhs);
3320   if (!lacc && !racc)
3321     return SRA_AM_NONE;
3322   /* Avoid modifying initializations of constant-pool replacements.  */
3323   if (racc && (racc->replacement_decl == lhs))
3324     return SRA_AM_NONE;
3325
3326   loc = gimple_location (stmt);
3327   if (lacc && lacc->grp_to_be_replaced)
3328     {
3329       lhs = get_access_replacement (lacc);
3330       gimple_assign_set_lhs (stmt, lhs);
3331       modify_this_stmt = true;
3332       if (lacc->grp_partial_lhs)
3333         force_gimple_rhs = true;
3334       sra_stats.exprs++;
3335     }
3336
3337   if (racc && racc->grp_to_be_replaced)
3338     {
3339       rhs = get_access_replacement (racc);
3340       modify_this_stmt = true;
3341       if (racc->grp_partial_lhs)
3342         force_gimple_rhs = true;
3343       sra_stats.exprs++;
3344     }
3345   else if (racc
3346            && !racc->grp_unscalarized_data
3347            && !racc->grp_unscalarizable_region
3348            && TREE_CODE (lhs) == SSA_NAME
3349            && !access_has_replacements_p (racc))
3350     {
3351       rhs = get_repl_default_def_ssa_name (racc);
3352       modify_this_stmt = true;
3353       sra_stats.exprs++;
3354     }
3355
3356   if (modify_this_stmt)
3357     {
3358       if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
3359         {
3360           /* If we can avoid creating a VIEW_CONVERT_EXPR do so.
3361              ???  This should move to fold_stmt which we simply should
3362              call after building a VIEW_CONVERT_EXPR here.  */
3363           if (AGGREGATE_TYPE_P (TREE_TYPE (lhs))
3364               && !contains_bitfld_component_ref_p (lhs))
3365             {
3366               lhs = build_ref_for_model (loc, lhs, 0, racc, gsi, false);
3367               gimple_assign_set_lhs (stmt, lhs);
3368             }
3369           else if (AGGREGATE_TYPE_P (TREE_TYPE (rhs))
3370                    && !contains_vce_or_bfcref_p (rhs))
3371             rhs = build_ref_for_model (loc, rhs, 0, lacc, gsi, false);
3372
3373           if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
3374             {
3375               rhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR, TREE_TYPE (lhs),
3376                                      rhs);
3377               if (is_gimple_reg_type (TREE_TYPE (lhs))
3378                   && TREE_CODE (lhs) != SSA_NAME)
3379                 force_gimple_rhs = true;
3380             }
3381         }
3382     }
3383
3384   if (lacc && lacc->grp_to_be_debug_replaced)
3385     {
3386       tree dlhs = get_access_replacement (lacc);
3387       tree drhs = unshare_expr (rhs);
3388       if (!useless_type_conversion_p (TREE_TYPE (dlhs), TREE_TYPE (drhs)))
3389         {
3390           if (AGGREGATE_TYPE_P (TREE_TYPE (drhs))
3391               && !contains_vce_or_bfcref_p (drhs))
3392             drhs = build_debug_ref_for_model (loc, drhs, 0, lacc);
3393           if (drhs
3394               && !useless_type_conversion_p (TREE_TYPE (dlhs),
3395                                              TREE_TYPE (drhs)))
3396             drhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR,
3397                                     TREE_TYPE (dlhs), drhs);
3398         }
3399       gdebug *ds = gimple_build_debug_bind (dlhs, drhs, stmt);
3400       gsi_insert_before (gsi, ds, GSI_SAME_STMT);
3401     }
3402
3403   /* From this point on, the function deals with assignments in between
3404      aggregates when at least one has scalar reductions of some of its
3405      components.  There are three possible scenarios: Both the LHS and RHS have
3406      to-be-scalarized components, 2) only the RHS has or 3) only the LHS has.
3407
3408      In the first case, we would like to load the LHS components from RHS
3409      components whenever possible.  If that is not possible, we would like to
3410      read it directly from the RHS (after updating it by storing in it its own
3411      components).  If there are some necessary unscalarized data in the LHS,
3412      those will be loaded by the original assignment too.  If neither of these
3413      cases happen, the original statement can be removed.  Most of this is done
3414      by load_assign_lhs_subreplacements.
3415
3416      In the second case, we would like to store all RHS scalarized components
3417      directly into LHS and if they cover the aggregate completely, remove the
3418      statement too.  In the third case, we want the LHS components to be loaded
3419      directly from the RHS (DSE will remove the original statement if it
3420      becomes redundant).
3421
3422      This is a bit complex but manageable when types match and when unions do
3423      not cause confusion in a way that we cannot really load a component of LHS
3424      from the RHS or vice versa (the access representing this level can have
3425      subaccesses that are accessible only through a different union field at a
3426      higher level - different from the one used in the examined expression).
3427      Unions are fun.
3428
3429      Therefore, I specially handle a fourth case, happening when there is a
3430      specific type cast or it is impossible to locate a scalarized subaccess on
3431      the other side of the expression.  If that happens, I simply "refresh" the
3432      RHS by storing in it is scalarized components leave the original statement
3433      there to do the copying and then load the scalar replacements of the LHS.
3434      This is what the first branch does.  */
3435
3436   if (modify_this_stmt
3437       || gimple_has_volatile_ops (stmt)
3438       || contains_vce_or_bfcref_p (rhs)
3439       || contains_vce_or_bfcref_p (lhs)
3440       || stmt_ends_bb_p (stmt))
3441     {
3442       /* No need to copy into a constant-pool, it comes pre-initialized.  */
3443       if (access_has_children_p (racc) && !constant_decl_p (racc->base))
3444         generate_subtree_copies (racc->first_child, rhs, racc->offset, 0, 0,
3445                                  gsi, false, false, loc);
3446       if (access_has_children_p (lacc))
3447         {
3448           gimple_stmt_iterator alt_gsi = gsi_none ();
3449           if (stmt_ends_bb_p (stmt))
3450             {
3451               alt_gsi = gsi_start_edge (single_non_eh_succ (gsi_bb (*gsi)));
3452               gsi = &alt_gsi;
3453             }
3454           generate_subtree_copies (lacc->first_child, lhs, lacc->offset, 0, 0,
3455                                    gsi, true, true, loc);
3456         }
3457       sra_stats.separate_lhs_rhs_handling++;
3458
3459       /* This gimplification must be done after generate_subtree_copies,
3460          lest we insert the subtree copies in the middle of the gimplified
3461          sequence.  */
3462       if (force_gimple_rhs)
3463         rhs = force_gimple_operand_gsi (&orig_gsi, rhs, true, NULL_TREE,
3464                                         true, GSI_SAME_STMT);
3465       if (gimple_assign_rhs1 (stmt) != rhs)
3466         {
3467           modify_this_stmt = true;
3468           gimple_assign_set_rhs_from_tree (&orig_gsi, rhs);
3469           gcc_assert (stmt == gsi_stmt (orig_gsi));
3470         }
3471
3472       return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
3473     }
3474   else
3475     {
3476       if (access_has_children_p (lacc)
3477           && access_has_children_p (racc)
3478           /* When an access represents an unscalarizable region, it usually
3479              represents accesses with variable offset and thus must not be used
3480              to generate new memory accesses.  */
3481           && !lacc->grp_unscalarizable_region
3482           && !racc->grp_unscalarizable_region)
3483         {
3484           struct subreplacement_assignment_data sad;
3485
3486           sad.left_offset = lacc->offset;
3487           sad.assignment_lhs = lhs;
3488           sad.assignment_rhs = rhs;
3489           sad.top_racc = racc;
3490           sad.old_gsi = *gsi;
3491           sad.new_gsi = gsi;
3492           sad.loc = gimple_location (stmt);
3493           sad.refreshed = SRA_UDH_NONE;
3494
3495           if (lacc->grp_read && !lacc->grp_covered)
3496             handle_unscalarized_data_in_subtree (&sad);
3497
3498           load_assign_lhs_subreplacements (lacc, &sad);
3499           if (sad.refreshed != SRA_UDH_RIGHT)
3500             {
3501               gsi_next (gsi);
3502               unlink_stmt_vdef (stmt);
3503               gsi_remove (&sad.old_gsi, true);
3504               release_defs (stmt);
3505               sra_stats.deleted++;
3506               return SRA_AM_REMOVED;
3507             }
3508         }
3509       else
3510         {
3511           if (access_has_children_p (racc)
3512               && !racc->grp_unscalarized_data
3513               && TREE_CODE (lhs) != SSA_NAME)
3514             {
3515               if (dump_file)
3516                 {
3517                   fprintf (dump_file, "Removing load: ");
3518                   print_gimple_stmt (dump_file, stmt, 0, 0);
3519                 }
3520               generate_subtree_copies (racc->first_child, lhs,
3521                                        racc->offset, 0, 0, gsi,
3522                                        false, false, loc);
3523               gcc_assert (stmt == gsi_stmt (*gsi));
3524               unlink_stmt_vdef (stmt);
3525               gsi_remove (gsi, true);
3526               release_defs (stmt);
3527               sra_stats.deleted++;
3528               return SRA_AM_REMOVED;
3529             }
3530           /* Restore the aggregate RHS from its components so the
3531              prevailing aggregate copy does the right thing.  */
3532           if (access_has_children_p (racc))
3533             generate_subtree_copies (racc->first_child, rhs, racc->offset, 0, 0,
3534                                      gsi, false, false, loc);
3535           /* Re-load the components of the aggregate copy destination.
3536              But use the RHS aggregate to load from to expose more
3537              optimization opportunities.  */
3538           if (access_has_children_p (lacc))
3539             generate_subtree_copies (lacc->first_child, rhs, lacc->offset,
3540                                      0, 0, gsi, true, true, loc);
3541         }
3542
3543       return SRA_AM_NONE;
3544     }
3545 }
3546
3547 /* Set any scalar replacements of values in the constant pool to the initial
3548    value of the constant.  (Constant-pool decls like *.LC0 have effectively
3549    been initialized before the program starts, we must do the same for their
3550    replacements.)  Thus, we output statements like 'SR.1 = *.LC0[0];' into
3551    the function's entry block.  */
3552
3553 static void
3554 initialize_constant_pool_replacements (void)
3555 {
3556   gimple_seq seq = NULL;
3557   gimple_stmt_iterator gsi = gsi_start (seq);
3558   bitmap_iterator bi;
3559   unsigned i;
3560
3561   EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
3562     {
3563       tree var = candidate (i);
3564       if (!constant_decl_p (var))
3565         continue;
3566       vec<access_p> *access_vec = get_base_access_vector (var);
3567       if (!access_vec)
3568         continue;
3569       for (unsigned i = 0; i < access_vec->length (); i++)
3570         {
3571           struct access *access = (*access_vec)[i];
3572           if (!access->replacement_decl)
3573             continue;
3574           gassign *stmt
3575             = gimple_build_assign (get_access_replacement (access),
3576                                    unshare_expr (access->expr));
3577           if (dump_file && (dump_flags & TDF_DETAILS))
3578             {
3579               fprintf (dump_file, "Generating constant initializer: ");
3580               print_gimple_stmt (dump_file, stmt, 0, 1);
3581               fprintf (dump_file, "\n");
3582             }
3583           gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
3584           update_stmt (stmt);
3585         }
3586     }
3587
3588   seq = gsi_seq (gsi);
3589   if (seq)
3590     gsi_insert_seq_on_edge_immediate (
3591       single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)), seq);
3592 }
3593
3594 /* Traverse the function body and all modifications as decided in
3595    analyze_all_variable_accesses.  Return true iff the CFG has been
3596    changed.  */
3597
3598 static bool
3599 sra_modify_function_body (void)
3600 {
3601   bool cfg_changed = false;
3602   basic_block bb;
3603
3604   initialize_constant_pool_replacements ();
3605
3606   FOR_EACH_BB_FN (bb, cfun)
3607     {
3608       gimple_stmt_iterator gsi = gsi_start_bb (bb);
3609       while (!gsi_end_p (gsi))
3610         {
3611           gimple *stmt = gsi_stmt (gsi);
3612           enum assignment_mod_result assign_result;
3613           bool modified = false, deleted = false;
3614           tree *t;
3615           unsigned i;
3616
3617           switch (gimple_code (stmt))
3618             {
3619             case GIMPLE_RETURN:
3620               t = gimple_return_retval_ptr (as_a <greturn *> (stmt));
3621               if (*t != NULL_TREE)
3622                 modified |= sra_modify_expr (t, &gsi, false);
3623               break;
3624
3625             case GIMPLE_ASSIGN:
3626               assign_result = sra_modify_assign (stmt, &gsi);
3627               modified |= assign_result == SRA_AM_MODIFIED;
3628               deleted = assign_result == SRA_AM_REMOVED;
3629               break;
3630
3631             case GIMPLE_CALL:
3632               /* Operands must be processed before the lhs.  */
3633               for (i = 0; i < gimple_call_num_args (stmt); i++)
3634                 {
3635                   t = gimple_call_arg_ptr (stmt, i);
3636                   modified |= sra_modify_expr (t, &gsi, false);
3637                 }
3638
3639               if (gimple_call_lhs (stmt))
3640                 {
3641                   t = gimple_call_lhs_ptr (stmt);
3642                   modified |= sra_modify_expr (t, &gsi, true);
3643                 }
3644               break;
3645
3646             case GIMPLE_ASM:
3647               {
3648                 gasm *asm_stmt = as_a <gasm *> (stmt);
3649                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
3650                   {
3651                     t = &TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
3652                     modified |= sra_modify_expr (t, &gsi, false);
3653                   }
3654                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
3655                   {
3656                     t = &TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
3657                     modified |= sra_modify_expr (t, &gsi, true);
3658                   }
3659               }
3660               break;
3661
3662             default:
3663               break;
3664             }
3665
3666           if (modified)
3667             {
3668               update_stmt (stmt);
3669               if (maybe_clean_eh_stmt (stmt)
3670                   && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
3671                 cfg_changed = true;
3672             }
3673           if (!deleted)
3674             gsi_next (&gsi);
3675         }
3676     }
3677
3678   gsi_commit_edge_inserts ();
3679   return cfg_changed;
3680 }
3681
3682 /* Generate statements initializing scalar replacements of parts of function
3683    parameters.  */
3684
3685 static void
3686 initialize_parameter_reductions (void)
3687 {
3688   gimple_stmt_iterator gsi;
3689   gimple_seq seq = NULL;
3690   tree parm;
3691
3692   gsi = gsi_start (seq);
3693   for (parm = DECL_ARGUMENTS (current_function_decl);
3694        parm;
3695        parm = DECL_CHAIN (parm))
3696     {
3697       vec<access_p> *access_vec;
3698       struct access *access;
3699
3700       if (!bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
3701         continue;
3702       access_vec = get_base_access_vector (parm);
3703       if (!access_vec)
3704         continue;
3705
3706       for (access = (*access_vec)[0];
3707            access;
3708            access = access->next_grp)
3709         generate_subtree_copies (access, parm, 0, 0, 0, &gsi, true, true,
3710                                  EXPR_LOCATION (parm));
3711     }
3712
3713   seq = gsi_seq (gsi);
3714   if (seq)
3715     gsi_insert_seq_on_edge_immediate (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)), seq);
3716 }
3717
3718 /* The "main" function of intraprocedural SRA passes.  Runs the analysis and if
3719    it reveals there are components of some aggregates to be scalarized, it runs
3720    the required transformations.  */
3721 static unsigned int
3722 perform_intra_sra (void)
3723 {
3724   int ret = 0;
3725   sra_initialize ();
3726
3727   if (!find_var_candidates ())
3728     goto out;
3729
3730   if (!scan_function ())
3731     goto out;
3732
3733   if (!analyze_all_variable_accesses ())
3734     goto out;
3735
3736   if (sra_modify_function_body ())
3737     ret = TODO_update_ssa | TODO_cleanup_cfg;
3738   else
3739     ret = TODO_update_ssa;
3740   initialize_parameter_reductions ();
3741
3742   statistics_counter_event (cfun, "Scalar replacements created",
3743                             sra_stats.replacements);
3744   statistics_counter_event (cfun, "Modified expressions", sra_stats.exprs);
3745   statistics_counter_event (cfun, "Subtree copy stmts",
3746                             sra_stats.subtree_copies);
3747   statistics_counter_event (cfun, "Subreplacement stmts",
3748                             sra_stats.subreplacements);
3749   statistics_counter_event (cfun, "Deleted stmts", sra_stats.deleted);
3750   statistics_counter_event (cfun, "Separate LHS and RHS handling",
3751                             sra_stats.separate_lhs_rhs_handling);
3752
3753  out:
3754   sra_deinitialize ();
3755   return ret;
3756 }
3757
3758 /* Perform early intraprocedural SRA.  */
3759 static unsigned int
3760 early_intra_sra (void)
3761 {
3762   sra_mode = SRA_MODE_EARLY_INTRA;
3763   return perform_intra_sra ();
3764 }
3765
3766 /* Perform "late" intraprocedural SRA.  */
3767 static unsigned int
3768 late_intra_sra (void)
3769 {
3770   sra_mode = SRA_MODE_INTRA;
3771   return perform_intra_sra ();
3772 }
3773
3774
3775 static bool
3776 gate_intra_sra (void)
3777 {
3778   return flag_tree_sra != 0 && dbg_cnt (tree_sra);
3779 }
3780
3781
3782 namespace {
3783
3784 const pass_data pass_data_sra_early =
3785 {
3786   GIMPLE_PASS, /* type */
3787   "esra", /* name */
3788   OPTGROUP_NONE, /* optinfo_flags */
3789   TV_TREE_SRA, /* tv_id */
3790   ( PROP_cfg | PROP_ssa ), /* properties_required */
3791   0, /* properties_provided */
3792   0, /* properties_destroyed */
3793   0, /* todo_flags_start */
3794   TODO_update_ssa, /* todo_flags_finish */
3795 };
3796
3797 class pass_sra_early : public gimple_opt_pass
3798 {
3799 public:
3800   pass_sra_early (gcc::context *ctxt)
3801     : gimple_opt_pass (pass_data_sra_early, ctxt)
3802   {}
3803
3804   /* opt_pass methods: */
3805   virtual bool gate (function *) { return gate_intra_sra (); }
3806   virtual unsigned int execute (function *) { return early_intra_sra (); }
3807
3808 }; // class pass_sra_early
3809
3810 } // anon namespace
3811
3812 gimple_opt_pass *
3813 make_pass_sra_early (gcc::context *ctxt)
3814 {
3815   return new pass_sra_early (ctxt);
3816 }
3817
3818 namespace {
3819
3820 const pass_data pass_data_sra =
3821 {
3822   GIMPLE_PASS, /* type */
3823   "sra", /* name */
3824   OPTGROUP_NONE, /* optinfo_flags */
3825   TV_TREE_SRA, /* tv_id */
3826   ( PROP_cfg | PROP_ssa ), /* properties_required */
3827   0, /* properties_provided */
3828   0, /* properties_destroyed */
3829   TODO_update_address_taken, /* todo_flags_start */
3830   TODO_update_ssa, /* todo_flags_finish */
3831 };
3832
3833 class pass_sra : public gimple_opt_pass
3834 {
3835 public:
3836   pass_sra (gcc::context *ctxt)
3837     : gimple_opt_pass (pass_data_sra, ctxt)
3838   {}
3839
3840   /* opt_pass methods: */
3841   virtual bool gate (function *) { return gate_intra_sra (); }
3842   virtual unsigned int execute (function *) { return late_intra_sra (); }
3843
3844 }; // class pass_sra
3845
3846 } // anon namespace
3847
3848 gimple_opt_pass *
3849 make_pass_sra (gcc::context *ctxt)
3850 {
3851   return new pass_sra (ctxt);
3852 }
3853
3854
3855 /* Return true iff PARM (which must be a parm_decl) is an unused scalar
3856    parameter.  */
3857
3858 static bool
3859 is_unused_scalar_param (tree parm)
3860 {
3861   tree name;
3862   return (is_gimple_reg (parm)
3863           && (!(name = ssa_default_def (cfun, parm))
3864               || has_zero_uses (name)));
3865 }
3866
3867 /* Scan immediate uses of a default definition SSA name of a parameter PARM and
3868    examine whether there are any direct or otherwise infeasible ones.  If so,
3869    return true, otherwise return false.  PARM must be a gimple register with a
3870    non-NULL default definition.  */
3871
3872 static bool
3873 ptr_parm_has_direct_uses (tree parm)
3874 {
3875   imm_use_iterator ui;
3876   gimple *stmt;
3877   tree name = ssa_default_def (cfun, parm);
3878   bool ret = false;
3879
3880   FOR_EACH_IMM_USE_STMT (stmt, ui, name)
3881     {
3882       int uses_ok = 0;
3883       use_operand_p use_p;
3884
3885       if (is_gimple_debug (stmt))
3886         continue;
3887
3888       /* Valid uses include dereferences on the lhs and the rhs.  */
3889       if (gimple_has_lhs (stmt))
3890         {
3891           tree lhs = gimple_get_lhs (stmt);
3892           while (handled_component_p (lhs))
3893             lhs = TREE_OPERAND (lhs, 0);
3894           if (TREE_CODE (lhs) == MEM_REF
3895               && TREE_OPERAND (lhs, 0) == name
3896               && integer_zerop (TREE_OPERAND (lhs, 1))
3897               && types_compatible_p (TREE_TYPE (lhs),
3898                                      TREE_TYPE (TREE_TYPE (name)))
3899               && !TREE_THIS_VOLATILE (lhs))
3900             uses_ok++;
3901         }
3902       if (gimple_assign_single_p (stmt))
3903         {
3904           tree rhs = gimple_assign_rhs1 (stmt);
3905           while (handled_component_p (rhs))
3906             rhs = TREE_OPERAND (rhs, 0);
3907           if (TREE_CODE (rhs) == MEM_REF
3908               && TREE_OPERAND (rhs, 0) == name
3909               && integer_zerop (TREE_OPERAND (rhs, 1))
3910               && types_compatible_p (TREE_TYPE (rhs),
3911                                      TREE_TYPE (TREE_TYPE (name)))
3912               && !TREE_THIS_VOLATILE (rhs))
3913             uses_ok++;
3914         }
3915       else if (is_gimple_call (stmt))
3916         {
3917           unsigned i;
3918           for (i = 0; i < gimple_call_num_args (stmt); ++i)
3919             {
3920               tree arg = gimple_call_arg (stmt, i);
3921               while (handled_component_p (arg))
3922                 arg = TREE_OPERAND (arg, 0);
3923               if (TREE_CODE (arg) == MEM_REF
3924                   && TREE_OPERAND (arg, 0) == name
3925                   && integer_zerop (TREE_OPERAND (arg, 1))
3926                   && types_compatible_p (TREE_TYPE (arg),
3927                                          TREE_TYPE (TREE_TYPE (name)))
3928                   && !TREE_THIS_VOLATILE (arg))
3929                 uses_ok++;
3930             }
3931         }
3932
3933       /* If the number of valid uses does not match the number of
3934          uses in this stmt there is an unhandled use.  */
3935       FOR_EACH_IMM_USE_ON_STMT (use_p, ui)
3936         --uses_ok;
3937
3938       if (uses_ok != 0)
3939         ret = true;
3940
3941       if (ret)
3942         BREAK_FROM_IMM_USE_STMT (ui);
3943     }
3944
3945   return ret;
3946 }
3947
3948 /* Identify candidates for reduction for IPA-SRA based on their type and mark
3949    them in candidate_bitmap.  Note that these do not necessarily include
3950    parameter which are unused and thus can be removed.  Return true iff any
3951    such candidate has been found.  */
3952
3953 static bool
3954 find_param_candidates (void)
3955 {
3956   tree parm;
3957   int count = 0;
3958   bool ret = false;
3959   const char *msg;
3960
3961   for (parm = DECL_ARGUMENTS (current_function_decl);
3962        parm;
3963        parm = DECL_CHAIN (parm))
3964     {
3965       tree type = TREE_TYPE (parm);
3966       tree_node **slot;
3967
3968       count++;
3969
3970       if (TREE_THIS_VOLATILE (parm)
3971           || TREE_ADDRESSABLE (parm)
3972           || (!is_gimple_reg_type (type) && is_va_list_type (type)))
3973         continue;
3974
3975       if (is_unused_scalar_param (parm))
3976         {
3977           ret = true;
3978           continue;
3979         }
3980
3981       if (POINTER_TYPE_P (type))
3982         {
3983           type = TREE_TYPE (type);
3984
3985           if (TREE_CODE (type) == FUNCTION_TYPE
3986               || TYPE_VOLATILE (type)
3987               || (TREE_CODE (type) == ARRAY_TYPE
3988                   && TYPE_NONALIASED_COMPONENT (type))
3989               || !is_gimple_reg (parm)
3990               || is_va_list_type (type)
3991               || ptr_parm_has_direct_uses (parm))
3992             continue;
3993         }
3994       else if (!AGGREGATE_TYPE_P (type))
3995         continue;
3996
3997       if (!COMPLETE_TYPE_P (type)
3998           || !tree_fits_uhwi_p (TYPE_SIZE (type))
3999           || tree_to_uhwi (TYPE_SIZE (type)) == 0
4000           || (AGGREGATE_TYPE_P (type)
4001               && type_internals_preclude_sra_p (type, &msg)))
4002         continue;
4003
4004       bitmap_set_bit (candidate_bitmap, DECL_UID (parm));
4005       slot = candidates->find_slot_with_hash (parm, DECL_UID (parm), INSERT);
4006       *slot = parm;
4007
4008       ret = true;
4009       if (dump_file && (dump_flags & TDF_DETAILS))
4010         {
4011           fprintf (dump_file, "Candidate (%d): ", DECL_UID (parm));
4012           print_generic_expr (dump_file, parm, 0);
4013           fprintf (dump_file, "\n");
4014         }
4015     }
4016
4017   func_param_count = count;
4018   return ret;
4019 }
4020
4021 /* Callback of walk_aliased_vdefs, marks the access passed as DATA as
4022    maybe_modified. */
4023
4024 static bool
4025 mark_maybe_modified (ao_ref *ao ATTRIBUTE_UNUSED, tree vdef ATTRIBUTE_UNUSED,
4026                      void *data)
4027 {
4028   struct access *repr = (struct access *) data;
4029
4030   repr->grp_maybe_modified = 1;
4031   return true;
4032 }
4033
4034 /* Analyze what representatives (in linked lists accessible from
4035    REPRESENTATIVES) can be modified by side effects of statements in the
4036    current function.  */
4037
4038 static void
4039 analyze_modified_params (vec<access_p> representatives)
4040 {
4041   int i;
4042
4043   for (i = 0; i < func_param_count; i++)
4044     {
4045       struct access *repr;
4046
4047       for (repr = representatives[i];
4048            repr;
4049            repr = repr->next_grp)
4050         {
4051           struct access *access;
4052           bitmap visited;
4053           ao_ref ar;
4054
4055           if (no_accesses_p (repr))
4056             continue;
4057           if (!POINTER_TYPE_P (TREE_TYPE (repr->base))
4058               || repr->grp_maybe_modified)
4059             continue;
4060
4061           ao_ref_init (&ar, repr->expr);
4062           visited = BITMAP_ALLOC (NULL);
4063           for (access = repr; access; access = access->next_sibling)
4064             {
4065               /* All accesses are read ones, otherwise grp_maybe_modified would
4066                  be trivially set.  */
4067               walk_aliased_vdefs (&ar, gimple_vuse (access->stmt),
4068                                   mark_maybe_modified, repr, &visited);
4069               if (repr->grp_maybe_modified)
4070                 break;
4071             }
4072           BITMAP_FREE (visited);
4073         }
4074     }
4075 }
4076
4077 /* Propagate distances in bb_dereferences in the opposite direction than the
4078    control flow edges, in each step storing the maximum of the current value
4079    and the minimum of all successors.  These steps are repeated until the table
4080    stabilizes.  Note that BBs which might terminate the functions (according to
4081    final_bbs bitmap) never updated in this way.  */
4082
4083 static void
4084 propagate_dereference_distances (void)
4085 {
4086   basic_block bb;
4087
4088   auto_vec<basic_block> queue (last_basic_block_for_fn (cfun));
4089   queue.quick_push (ENTRY_BLOCK_PTR_FOR_FN (cfun));
4090   FOR_EACH_BB_FN (bb, cfun)
4091     {
4092       queue.quick_push (bb);
4093       bb->aux = bb;
4094     }
4095
4096   while (!queue.is_empty ())
4097     {
4098       edge_iterator ei;
4099       edge e;
4100       bool change = false;
4101       int i;
4102
4103       bb = queue.pop ();
4104       bb->aux = NULL;
4105
4106       if (bitmap_bit_p (final_bbs, bb->index))
4107         continue;
4108
4109       for (i = 0; i < func_param_count; i++)
4110         {
4111           int idx = bb->index * func_param_count + i;
4112           bool first = true;
4113           HOST_WIDE_INT inh = 0;
4114
4115           FOR_EACH_EDGE (e, ei, bb->succs)
4116           {
4117             int succ_idx = e->dest->index * func_param_count + i;
4118
4119             if (e->src == EXIT_BLOCK_PTR_FOR_FN (cfun))
4120               continue;
4121
4122             if (first)
4123               {
4124                 first = false;
4125                 inh = bb_dereferences [succ_idx];
4126               }
4127             else if (bb_dereferences [succ_idx] < inh)
4128               inh = bb_dereferences [succ_idx];
4129           }
4130
4131           if (!first && bb_dereferences[idx] < inh)
4132             {
4133               bb_dereferences[idx] = inh;
4134               change = true;
4135             }
4136         }
4137
4138       if (change && !bitmap_bit_p (final_bbs, bb->index))
4139         FOR_EACH_EDGE (e, ei, bb->preds)
4140           {
4141             if (e->src->aux)
4142               continue;
4143
4144             e->src->aux = e->src;
4145             queue.quick_push (e->src);
4146           }
4147     }
4148 }
4149
4150 /* Dump a dereferences TABLE with heading STR to file F.  */
4151
4152 static void
4153 dump_dereferences_table (FILE *f, const char *str, HOST_WIDE_INT *table)
4154 {
4155   basic_block bb;
4156
4157   fprintf (dump_file, "%s", str);
4158   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun),
4159                   EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb)
4160     {
4161       fprintf (f, "%4i  %i   ", bb->index, bitmap_bit_p (final_bbs, bb->index));
4162       if (bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
4163         {
4164           int i;
4165           for (i = 0; i < func_param_count; i++)
4166             {
4167               int idx = bb->index * func_param_count + i;
4168               fprintf (f, " %4" HOST_WIDE_INT_PRINT "d", table[idx]);
4169             }
4170         }
4171       fprintf (f, "\n");
4172     }
4173   fprintf (dump_file, "\n");
4174 }
4175
4176 /* Determine what (parts of) parameters passed by reference that are not
4177    assigned to are not certainly dereferenced in this function and thus the
4178    dereferencing cannot be safely moved to the caller without potentially
4179    introducing a segfault.  Mark such REPRESENTATIVES as
4180    grp_not_necessarilly_dereferenced.
4181
4182    The dereferenced maximum "distance," i.e. the offset + size of the accessed
4183    part is calculated rather than simple booleans are calculated for each
4184    pointer parameter to handle cases when only a fraction of the whole
4185    aggregate is allocated (see testsuite/gcc.c-torture/execute/ipa-sra-2.c for
4186    an example).
4187
4188    The maximum dereference distances for each pointer parameter and BB are
4189    already stored in bb_dereference.  This routine simply propagates these
4190    values upwards by propagate_dereference_distances and then compares the
4191    distances of individual parameters in the ENTRY BB to the equivalent
4192    distances of each representative of a (fraction of a) parameter.  */
4193
4194 static void
4195 analyze_caller_dereference_legality (vec<access_p> representatives)
4196 {
4197   int i;
4198
4199   if (dump_file && (dump_flags & TDF_DETAILS))
4200     dump_dereferences_table (dump_file,
4201                              "Dereference table before propagation:\n",
4202                              bb_dereferences);
4203
4204   propagate_dereference_distances ();
4205
4206   if (dump_file && (dump_flags & TDF_DETAILS))
4207     dump_dereferences_table (dump_file,
4208                              "Dereference table after propagation:\n",
4209                              bb_dereferences);
4210
4211   for (i = 0; i < func_param_count; i++)
4212     {
4213       struct access *repr = representatives[i];
4214       int idx = ENTRY_BLOCK_PTR_FOR_FN (cfun)->index * func_param_count + i;
4215
4216       if (!repr || no_accesses_p (repr))
4217         continue;
4218
4219       do
4220         {
4221           if ((repr->offset + repr->size) > bb_dereferences[idx])
4222             repr->grp_not_necessarilly_dereferenced = 1;
4223           repr = repr->next_grp;
4224         }
4225       while (repr);
4226     }
4227 }
4228
4229 /* Return the representative access for the parameter declaration PARM if it is
4230    a scalar passed by reference which is not written to and the pointer value
4231    is not used directly.  Thus, if it is legal to dereference it in the caller
4232    and we can rule out modifications through aliases, such parameter should be
4233    turned into one passed by value.  Return NULL otherwise.  */
4234
4235 static struct access *
4236 unmodified_by_ref_scalar_representative (tree parm)
4237 {
4238   int i, access_count;
4239   struct access *repr;
4240   vec<access_p> *access_vec;
4241
4242   access_vec = get_base_access_vector (parm);
4243   gcc_assert (access_vec);
4244   repr = (*access_vec)[0];
4245   if (repr->write)
4246     return NULL;
4247   repr->group_representative = repr;
4248
4249   access_count = access_vec->length ();
4250   for (i = 1; i < access_count; i++)
4251     {
4252       struct access *access = (*access_vec)[i];
4253       if (access->write)
4254         return NULL;
4255       access->group_representative = repr;
4256       access->next_sibling = repr->next_sibling;
4257       repr->next_sibling = access;
4258     }
4259
4260   repr->grp_read = 1;
4261   repr->grp_scalar_ptr = 1;
4262   return repr;
4263 }
4264
4265 /* Return true iff this ACCESS precludes IPA-SRA of the parameter it is
4266    associated with.  REQ_ALIGN is the minimum required alignment.  */
4267
4268 static bool
4269 access_precludes_ipa_sra_p (struct access *access, unsigned int req_align)
4270 {
4271   unsigned int exp_align;
4272   /* Avoid issues such as the second simple testcase in PR 42025.  The problem
4273      is incompatible assign in a call statement (and possibly even in asm
4274      statements).  This can be relaxed by using a new temporary but only for
4275      non-TREE_ADDRESSABLE types and is probably not worth the complexity. (In
4276      intraprocedural SRA we deal with this by keeping the old aggregate around,
4277      something we cannot do in IPA-SRA.)  */
4278   if (access->write
4279       && (is_gimple_call (access->stmt)
4280           || gimple_code (access->stmt) == GIMPLE_ASM))
4281     return true;
4282
4283   exp_align = get_object_alignment (access->expr);
4284   if (exp_align < req_align)
4285     return true;
4286
4287   return false;
4288 }
4289
4290
4291 /* Sort collected accesses for parameter PARM, identify representatives for
4292    each accessed region and link them together.  Return NULL if there are
4293    different but overlapping accesses, return the special ptr value meaning
4294    there are no accesses for this parameter if that is the case and return the
4295    first representative otherwise.  Set *RO_GRP if there is a group of accesses
4296    with only read (i.e. no write) accesses.  */
4297
4298 static struct access *
4299 splice_param_accesses (tree parm, bool *ro_grp)
4300 {
4301   int i, j, access_count, group_count;
4302   int agg_size, total_size = 0;
4303   struct access *access, *res, **prev_acc_ptr = &res;
4304   vec<access_p> *access_vec;
4305
4306   access_vec = get_base_access_vector (parm);
4307   if (!access_vec)
4308     return &no_accesses_representant;
4309   access_count = access_vec->length ();
4310
4311   access_vec->qsort (compare_access_positions);
4312
4313   i = 0;
4314   total_size = 0;
4315   group_count = 0;
4316   while (i < access_count)
4317     {
4318       bool modification;
4319       tree a1_alias_type;
4320       access = (*access_vec)[i];
4321       modification = access->write;
4322       if (access_precludes_ipa_sra_p (access, TYPE_ALIGN (access->type)))
4323         return NULL;
4324       a1_alias_type = reference_alias_ptr_type (access->expr);
4325
4326       /* Access is about to become group representative unless we find some
4327          nasty overlap which would preclude us from breaking this parameter
4328          apart. */
4329
4330       j = i + 1;
4331       while (j < access_count)
4332         {
4333           struct access *ac2 = (*access_vec)[j];
4334           if (ac2->offset != access->offset)
4335             {
4336               /* All or nothing law for parameters. */
4337               if (access->offset + access->size > ac2->offset)
4338                 return NULL;
4339               else
4340                 break;
4341             }
4342           else if (ac2->size != access->size)
4343             return NULL;
4344
4345           if (access_precludes_ipa_sra_p (ac2, TYPE_ALIGN (access->type))
4346               || (ac2->type != access->type
4347                   && (TREE_ADDRESSABLE (ac2->type)
4348                       || TREE_ADDRESSABLE (access->type)))
4349               || (reference_alias_ptr_type (ac2->expr) != a1_alias_type))
4350             return NULL;
4351
4352           modification |= ac2->write;
4353           ac2->group_representative = access;
4354           ac2->next_sibling = access->next_sibling;
4355           access->next_sibling = ac2;
4356           j++;
4357         }
4358
4359       group_count++;
4360       access->grp_maybe_modified = modification;
4361       if (!modification)
4362         *ro_grp = true;
4363       *prev_acc_ptr = access;
4364       prev_acc_ptr = &access->next_grp;
4365       total_size += access->size;
4366       i = j;
4367     }
4368
4369   if (POINTER_TYPE_P (TREE_TYPE (parm)))
4370     agg_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (TREE_TYPE (parm))));
4371   else
4372     agg_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (parm)));
4373   if (total_size >= agg_size)
4374     return NULL;
4375
4376   gcc_assert (group_count > 0);
4377   return res;
4378 }
4379
4380 /* Decide whether parameters with representative accesses given by REPR should
4381    be reduced into components.  */
4382
4383 static int
4384 decide_one_param_reduction (struct access *repr)
4385 {
4386   int total_size, cur_parm_size, agg_size, new_param_count, parm_size_limit;
4387   bool by_ref;
4388   tree parm;
4389
4390   parm = repr->base;
4391   cur_parm_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (parm)));
4392   gcc_assert (cur_parm_size > 0);
4393
4394   if (POINTER_TYPE_P (TREE_TYPE (parm)))
4395     {
4396       by_ref = true;
4397       agg_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (TREE_TYPE (parm))));
4398     }
4399   else
4400     {
4401       by_ref = false;
4402       agg_size = cur_parm_size;
4403     }
4404
4405   if (dump_file)
4406     {
4407       struct access *acc;
4408       fprintf (dump_file, "Evaluating PARAM group sizes for ");
4409       print_generic_expr (dump_file, parm, 0);
4410       fprintf (dump_file, " (UID: %u): \n", DECL_UID (parm));
4411       for (acc = repr; acc; acc = acc->next_grp)
4412         dump_access (dump_file, acc, true);
4413     }
4414
4415   total_size = 0;
4416   new_param_count = 0;
4417
4418   for (; repr; repr = repr->next_grp)
4419     {
4420       gcc_assert (parm == repr->base);
4421
4422       /* Taking the address of a non-addressable field is verboten.  */
4423       if (by_ref && repr->non_addressable)
4424         return 0;
4425
4426       /* Do not decompose a non-BLKmode param in a way that would
4427          create BLKmode params.  Especially for by-reference passing
4428          (thus, pointer-type param) this is hardly worthwhile.  */
4429       if (DECL_MODE (parm) != BLKmode
4430           && TYPE_MODE (repr->type) == BLKmode)
4431         return 0;
4432
4433       if (!by_ref || (!repr->grp_maybe_modified
4434                       && !repr->grp_not_necessarilly_dereferenced))
4435         total_size += repr->size;
4436       else
4437         total_size += cur_parm_size;
4438
4439       new_param_count++;
4440     }
4441
4442   gcc_assert (new_param_count > 0);
4443
4444   if (optimize_function_for_size_p (cfun))
4445     parm_size_limit = cur_parm_size;
4446   else
4447     parm_size_limit = (PARAM_VALUE (PARAM_IPA_SRA_PTR_GROWTH_FACTOR)
4448                        * cur_parm_size);
4449
4450   if (total_size < agg_size
4451       && total_size <= parm_size_limit)
4452     {
4453       if (dump_file)
4454         fprintf (dump_file, "    ....will be split into %i components\n",
4455                  new_param_count);
4456       return new_param_count;
4457     }
4458   else
4459     return 0;
4460 }
4461
4462 /* The order of the following enums is important, we need to do extra work for
4463    UNUSED_PARAMS, BY_VAL_ACCESSES and UNMODIF_BY_REF_ACCESSES.  */
4464 enum ipa_splicing_result { NO_GOOD_ACCESS, UNUSED_PARAMS, BY_VAL_ACCESSES,
4465                           MODIF_BY_REF_ACCESSES, UNMODIF_BY_REF_ACCESSES };
4466
4467 /* Identify representatives of all accesses to all candidate parameters for
4468    IPA-SRA.  Return result based on what representatives have been found. */
4469
4470 static enum ipa_splicing_result
4471 splice_all_param_accesses (vec<access_p> &representatives)
4472 {
4473   enum ipa_splicing_result result = NO_GOOD_ACCESS;
4474   tree parm;
4475   struct access *repr;
4476
4477   representatives.create (func_param_count);
4478
4479   for (parm = DECL_ARGUMENTS (current_function_decl);
4480        parm;
4481        parm = DECL_CHAIN (parm))
4482     {
4483       if (is_unused_scalar_param (parm))
4484         {
4485           representatives.quick_push (&no_accesses_representant);
4486           if (result == NO_GOOD_ACCESS)
4487             result = UNUSED_PARAMS;
4488         }
4489       else if (POINTER_TYPE_P (TREE_TYPE (parm))
4490                && is_gimple_reg_type (TREE_TYPE (TREE_TYPE (parm)))
4491                && bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
4492         {
4493           repr = unmodified_by_ref_scalar_representative (parm);
4494           representatives.quick_push (repr);
4495           if (repr)
4496             result = UNMODIF_BY_REF_ACCESSES;
4497         }
4498       else if (bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
4499         {
4500           bool ro_grp = false;
4501           repr = splice_param_accesses (parm, &ro_grp);
4502           representatives.quick_push (repr);
4503
4504           if (repr && !no_accesses_p (repr))
4505             {
4506               if (POINTER_TYPE_P (TREE_TYPE (parm)))
4507                 {
4508                   if (ro_grp)
4509                     result = UNMODIF_BY_REF_ACCESSES;
4510                   else if (result < MODIF_BY_REF_ACCESSES)
4511                     result = MODIF_BY_REF_ACCESSES;
4512                 }
4513               else if (result < BY_VAL_ACCESSES)
4514                 result = BY_VAL_ACCESSES;
4515             }
4516           else if (no_accesses_p (repr) && (result == NO_GOOD_ACCESS))
4517             result = UNUSED_PARAMS;
4518         }
4519       else
4520         representatives.quick_push (NULL);
4521     }
4522
4523   if (result == NO_GOOD_ACCESS)
4524     {
4525       representatives.release ();
4526       return NO_GOOD_ACCESS;
4527     }
4528
4529   return result;
4530 }
4531
4532 /* Return the index of BASE in PARMS.  Abort if it is not found.  */
4533
4534 static inline int
4535 get_param_index (tree base, vec<tree> parms)
4536 {
4537   int i, len;
4538
4539   len = parms.length ();
4540   for (i = 0; i < len; i++)
4541     if (parms[i] == base)
4542       return i;
4543   gcc_unreachable ();
4544 }
4545
4546 /* Convert the decisions made at the representative level into compact
4547    parameter adjustments.  REPRESENTATIVES are pointers to first
4548    representatives of each param accesses, ADJUSTMENTS_COUNT is the expected
4549    final number of adjustments.  */
4550
4551 static ipa_parm_adjustment_vec
4552 turn_representatives_into_adjustments (vec<access_p> representatives,
4553                                        int adjustments_count)
4554 {
4555   vec<tree> parms;
4556   ipa_parm_adjustment_vec adjustments;
4557   tree parm;
4558   int i;
4559
4560   gcc_assert (adjustments_count > 0);
4561   parms = ipa_get_vector_of_formal_parms (current_function_decl);
4562   adjustments.create (adjustments_count);
4563   parm = DECL_ARGUMENTS (current_function_decl);
4564   for (i = 0; i < func_param_count; i++, parm = DECL_CHAIN (parm))
4565     {
4566       struct access *repr = representatives[i];
4567
4568       if (!repr || no_accesses_p (repr))
4569         {
4570           struct ipa_parm_adjustment adj;
4571
4572           memset (&adj, 0, sizeof (adj));
4573           adj.base_index = get_param_index (parm, parms);
4574           adj.base = parm;
4575           if (!repr)
4576             adj.op = IPA_PARM_OP_COPY;
4577           else
4578             adj.op = IPA_PARM_OP_REMOVE;
4579           adj.arg_prefix = "ISRA";
4580           adjustments.quick_push (adj);
4581         }
4582       else
4583         {
4584           struct ipa_parm_adjustment adj;
4585           int index = get_param_index (parm, parms);
4586
4587           for (; repr; repr = repr->next_grp)
4588             {
4589               memset (&adj, 0, sizeof (adj));
4590               gcc_assert (repr->base == parm);
4591               adj.base_index = index;
4592               adj.base = repr->base;
4593               adj.type = repr->type;
4594               adj.alias_ptr_type = reference_alias_ptr_type (repr->expr);
4595               adj.offset = repr->offset;
4596               adj.reverse = repr->reverse;
4597               adj.by_ref = (POINTER_TYPE_P (TREE_TYPE (repr->base))
4598                             && (repr->grp_maybe_modified
4599                                 || repr->grp_not_necessarilly_dereferenced));
4600               adj.arg_prefix = "ISRA";
4601               adjustments.quick_push (adj);
4602             }
4603         }
4604     }
4605   parms.release ();
4606   return adjustments;
4607 }
4608
4609 /* Analyze the collected accesses and produce a plan what to do with the
4610    parameters in the form of adjustments, NULL meaning nothing.  */
4611
4612 static ipa_parm_adjustment_vec
4613 analyze_all_param_acesses (void)
4614 {
4615   enum ipa_splicing_result repr_state;
4616   bool proceed = false;
4617   int i, adjustments_count = 0;
4618   vec<access_p> representatives;
4619   ipa_parm_adjustment_vec adjustments;
4620
4621   repr_state = splice_all_param_accesses (representatives);
4622   if (repr_state == NO_GOOD_ACCESS)
4623     return ipa_parm_adjustment_vec ();
4624
4625   /* If there are any parameters passed by reference which are not modified
4626      directly, we need to check whether they can be modified indirectly.  */
4627   if (repr_state == UNMODIF_BY_REF_ACCESSES)
4628     {
4629       analyze_caller_dereference_legality (representatives);
4630       analyze_modified_params (representatives);
4631     }
4632
4633   for (i = 0; i < func_param_count; i++)
4634     {
4635       struct access *repr = representatives[i];
4636
4637       if (repr && !no_accesses_p (repr))
4638         {
4639           if (repr->grp_scalar_ptr)
4640             {
4641               adjustments_count++;
4642               if (repr->grp_not_necessarilly_dereferenced
4643                   || repr->grp_maybe_modified)
4644                 representatives[i] = NULL;
4645               else
4646                 {
4647                   proceed = true;
4648                   sra_stats.scalar_by_ref_to_by_val++;
4649                 }
4650             }
4651           else
4652             {
4653               int new_components = decide_one_param_reduction (repr);
4654
4655               if (new_components == 0)
4656                 {
4657                   representatives[i] = NULL;
4658                   adjustments_count++;
4659                 }
4660               else
4661                 {
4662                   adjustments_count += new_components;
4663                   sra_stats.aggregate_params_reduced++;
4664                   sra_stats.param_reductions_created += new_components;
4665                   proceed = true;
4666                 }
4667             }
4668         }
4669       else
4670         {
4671           if (no_accesses_p (repr))
4672             {
4673               proceed = true;
4674               sra_stats.deleted_unused_parameters++;
4675             }
4676           adjustments_count++;
4677         }
4678     }
4679
4680   if (!proceed && dump_file)
4681     fprintf (dump_file, "NOT proceeding to change params.\n");
4682
4683   if (proceed)
4684     adjustments = turn_representatives_into_adjustments (representatives,
4685                                                          adjustments_count);
4686   else
4687     adjustments = ipa_parm_adjustment_vec ();
4688
4689   representatives.release ();
4690   return adjustments;
4691 }
4692
4693 /* If a parameter replacement identified by ADJ does not yet exist in the form
4694    of declaration, create it and record it, otherwise return the previously
4695    created one.  */
4696
4697 static tree
4698 get_replaced_param_substitute (struct ipa_parm_adjustment *adj)
4699 {
4700   tree repl;
4701   if (!adj->new_ssa_base)
4702     {
4703       char *pretty_name = make_fancy_name (adj->base);
4704
4705       repl = create_tmp_reg (TREE_TYPE (adj->base), "ISR");
4706       DECL_NAME (repl) = get_identifier (pretty_name);
4707       DECL_NAMELESS (repl) = 1;
4708       obstack_free (&name_obstack, pretty_name);
4709
4710       adj->new_ssa_base = repl;
4711     }
4712   else
4713     repl = adj->new_ssa_base;
4714   return repl;
4715 }
4716
4717 /* Find the first adjustment for a particular parameter BASE in a vector of
4718    ADJUSTMENTS which is not a copy_param.  Return NULL if there is no such
4719    adjustment. */
4720
4721 static struct ipa_parm_adjustment *
4722 get_adjustment_for_base (ipa_parm_adjustment_vec adjustments, tree base)
4723 {
4724   int i, len;
4725
4726   len = adjustments.length ();
4727   for (i = 0; i < len; i++)
4728     {
4729       struct ipa_parm_adjustment *adj;
4730
4731       adj = &adjustments[i];
4732       if (adj->op != IPA_PARM_OP_COPY && adj->base == base)
4733         return adj;
4734     }
4735
4736   return NULL;
4737 }
4738
4739 /* If OLD_NAME, which is being defined by statement STMT, is an SSA_NAME of a
4740    parameter which is to be removed because its value is not used, create a new
4741    SSA_NAME relating to a replacement VAR_DECL, replace all uses of the
4742    original with it and return it.  If there is no need to re-map, return NULL.
4743    ADJUSTMENTS is a pointer to a vector of IPA-SRA adjustments.  */
4744
4745 static tree
4746 replace_removed_params_ssa_names (tree old_name, gimple *stmt,
4747                                   ipa_parm_adjustment_vec adjustments)
4748 {
4749   struct ipa_parm_adjustment *adj;
4750   tree decl, repl, new_name;
4751
4752   if (TREE_CODE (old_name) != SSA_NAME)
4753     return NULL;
4754
4755   decl = SSA_NAME_VAR (old_name);
4756   if (decl == NULL_TREE
4757       || TREE_CODE (decl) != PARM_DECL)
4758     return NULL;
4759
4760   adj = get_adjustment_for_base (adjustments, decl);
4761   if (!adj)
4762     return NULL;
4763
4764   repl = get_replaced_param_substitute (adj);
4765   new_name = make_ssa_name (repl, stmt);
4766   SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name)
4767     = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (old_name);
4768
4769   if (dump_file)
4770     {
4771       fprintf (dump_file, "replacing an SSA name of a removed param ");
4772       print_generic_expr (dump_file, old_name, 0);
4773       fprintf (dump_file, " with ");
4774       print_generic_expr (dump_file, new_name, 0);
4775       fprintf (dump_file, "\n");
4776     }
4777
4778   replace_uses_by (old_name, new_name);
4779   return new_name;
4780 }
4781
4782 /* If the statement STMT contains any expressions that need to replaced with a
4783    different one as noted by ADJUSTMENTS, do so.  Handle any potential type
4784    incompatibilities (GSI is used to accommodate conversion statements and must
4785    point to the statement).  Return true iff the statement was modified.  */
4786
4787 static bool
4788 sra_ipa_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi,
4789                        ipa_parm_adjustment_vec adjustments)
4790 {
4791   tree *lhs_p, *rhs_p;
4792   bool any;
4793
4794   if (!gimple_assign_single_p (stmt))
4795     return false;
4796
4797   rhs_p = gimple_assign_rhs1_ptr (stmt);
4798   lhs_p = gimple_assign_lhs_ptr (stmt);
4799
4800   any = ipa_modify_expr (rhs_p, false, adjustments);
4801   any |= ipa_modify_expr (lhs_p, false, adjustments);
4802   if (any)
4803     {
4804       tree new_rhs = NULL_TREE;
4805
4806       if (!useless_type_conversion_p (TREE_TYPE (*lhs_p), TREE_TYPE (*rhs_p)))
4807         {
4808           if (TREE_CODE (*rhs_p) == CONSTRUCTOR)
4809             {
4810               /* V_C_Es of constructors can cause trouble (PR 42714).  */
4811               if (is_gimple_reg_type (TREE_TYPE (*lhs_p)))
4812                 *rhs_p = build_zero_cst (TREE_TYPE (*lhs_p));
4813               else
4814                 *rhs_p = build_constructor (TREE_TYPE (*lhs_p),
4815                                             NULL);
4816             }
4817           else
4818             new_rhs = fold_build1_loc (gimple_location (stmt),
4819                                        VIEW_CONVERT_EXPR, TREE_TYPE (*lhs_p),
4820                                        *rhs_p);
4821         }
4822       else if (REFERENCE_CLASS_P (*rhs_p)
4823                && is_gimple_reg_type (TREE_TYPE (*lhs_p))
4824                && !is_gimple_reg (*lhs_p))
4825         /* This can happen when an assignment in between two single field
4826            structures is turned into an assignment in between two pointers to
4827            scalars (PR 42237).  */
4828         new_rhs = *rhs_p;
4829
4830       if (new_rhs)
4831         {
4832           tree tmp = force_gimple_operand_gsi (gsi, new_rhs, true, NULL_TREE,
4833                                                true, GSI_SAME_STMT);
4834
4835           gimple_assign_set_rhs_from_tree (gsi, tmp);
4836         }
4837
4838       return true;
4839     }
4840
4841   return false;
4842 }
4843
4844 /* Traverse the function body and all modifications as described in
4845    ADJUSTMENTS.  Return true iff the CFG has been changed.  */
4846
4847 bool
4848 ipa_sra_modify_function_body (ipa_parm_adjustment_vec adjustments)
4849 {
4850   bool cfg_changed = false;
4851   basic_block bb;
4852
4853   FOR_EACH_BB_FN (bb, cfun)
4854     {
4855       gimple_stmt_iterator gsi;
4856
4857       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
4858         {
4859           gphi *phi = as_a <gphi *> (gsi_stmt (gsi));
4860           tree new_lhs, old_lhs = gimple_phi_result (phi);
4861           new_lhs = replace_removed_params_ssa_names (old_lhs, phi, adjustments);
4862           if (new_lhs)
4863             {
4864               gimple_phi_set_result (phi, new_lhs);
4865               release_ssa_name (old_lhs);
4866             }
4867         }
4868
4869       gsi = gsi_start_bb (bb);
4870       while (!gsi_end_p (gsi))
4871         {
4872           gimple *stmt = gsi_stmt (gsi);
4873           bool modified = false;
4874           tree *t;
4875           unsigned i;
4876
4877           switch (gimple_code (stmt))
4878             {
4879             case GIMPLE_RETURN:
4880               t = gimple_return_retval_ptr (as_a <greturn *> (stmt));
4881               if (*t != NULL_TREE)
4882                 modified |= ipa_modify_expr (t, true, adjustments);
4883               break;
4884
4885             case GIMPLE_ASSIGN:
4886               modified |= sra_ipa_modify_assign (stmt, &gsi, adjustments);
4887               break;
4888
4889             case GIMPLE_CALL:
4890               /* Operands must be processed before the lhs.  */
4891               for (i = 0; i < gimple_call_num_args (stmt); i++)
4892                 {
4893                   t = gimple_call_arg_ptr (stmt, i);
4894                   modified |= ipa_modify_expr (t, true, adjustments);
4895                 }
4896
4897               if (gimple_call_lhs (stmt))
4898                 {
4899                   t = gimple_call_lhs_ptr (stmt);
4900                   modified |= ipa_modify_expr (t, false, adjustments);
4901                 }
4902               break;
4903
4904             case GIMPLE_ASM:
4905               {
4906                 gasm *asm_stmt = as_a <gasm *> (stmt);
4907                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
4908                   {
4909                     t = &TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
4910                     modified |= ipa_modify_expr (t, true, adjustments);
4911                   }
4912                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
4913                   {
4914                     t = &TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
4915                     modified |= ipa_modify_expr (t, false, adjustments);
4916                   }
4917               }
4918               break;
4919
4920             default:
4921               break;
4922             }
4923
4924           def_operand_p defp;
4925           ssa_op_iter iter;
4926           FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_DEF)
4927             {
4928               tree old_def = DEF_FROM_PTR (defp);
4929               if (tree new_def = replace_removed_params_ssa_names (old_def, stmt,
4930                                                                    adjustments))
4931                 {
4932                   SET_DEF (defp, new_def);
4933                   release_ssa_name (old_def);
4934                   modified = true;
4935                 }
4936             }
4937
4938           if (modified)
4939             {
4940               update_stmt (stmt);
4941               if (maybe_clean_eh_stmt (stmt)
4942                   && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
4943                 cfg_changed = true;
4944             }
4945           gsi_next (&gsi);
4946         }
4947     }
4948
4949   return cfg_changed;
4950 }
4951
4952 /* Call gimple_debug_bind_reset_value on all debug statements describing
4953    gimple register parameters that are being removed or replaced.  */
4954
4955 static void
4956 sra_ipa_reset_debug_stmts (ipa_parm_adjustment_vec adjustments)
4957 {
4958   int i, len;
4959   gimple_stmt_iterator *gsip = NULL, gsi;
4960
4961   if (MAY_HAVE_DEBUG_STMTS && single_succ_p (ENTRY_BLOCK_PTR_FOR_FN (cfun)))
4962     {
4963       gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
4964       gsip = &gsi;
4965     }
4966   len = adjustments.length ();
4967   for (i = 0; i < len; i++)
4968     {
4969       struct ipa_parm_adjustment *adj;
4970       imm_use_iterator ui;
4971       gimple *stmt;
4972       gdebug *def_temp;
4973       tree name, vexpr, copy = NULL_TREE;
4974       use_operand_p use_p;
4975
4976       adj = &adjustments[i];
4977       if (adj->op == IPA_PARM_OP_COPY || !is_gimple_reg (adj->base))
4978         continue;
4979       name = ssa_default_def (cfun, adj->base);
4980       vexpr = NULL;
4981       if (name)
4982         FOR_EACH_IMM_USE_STMT (stmt, ui, name)
4983           {
4984             if (gimple_clobber_p (stmt))
4985               {
4986                 gimple_stmt_iterator cgsi = gsi_for_stmt (stmt);
4987                 unlink_stmt_vdef (stmt);
4988                 gsi_remove (&cgsi, true);
4989                 release_defs (stmt);
4990                 continue;
4991               }
4992             /* All other users must have been removed by
4993                ipa_sra_modify_function_body.  */
4994             gcc_assert (is_gimple_debug (stmt));
4995             if (vexpr == NULL && gsip != NULL)
4996               {
4997                 gcc_assert (TREE_CODE (adj->base) == PARM_DECL);
4998                 vexpr = make_node (DEBUG_EXPR_DECL);
4999                 def_temp = gimple_build_debug_source_bind (vexpr, adj->base,
5000                                                            NULL);
5001                 DECL_ARTIFICIAL (vexpr) = 1;
5002                 TREE_TYPE (vexpr) = TREE_TYPE (name);
5003                 SET_DECL_MODE (vexpr, DECL_MODE (adj->base));
5004                 gsi_insert_before (gsip, def_temp, GSI_SAME_STMT);
5005               }
5006             if (vexpr)
5007               {
5008                 FOR_EACH_IMM_USE_ON_STMT (use_p, ui)
5009                   SET_USE (use_p, vexpr);
5010               }
5011             else
5012               gimple_debug_bind_reset_value (stmt);
5013             update_stmt (stmt);
5014           }
5015       /* Create a VAR_DECL for debug info purposes.  */
5016       if (!DECL_IGNORED_P (adj->base))
5017         {
5018           copy = build_decl (DECL_SOURCE_LOCATION (current_function_decl),
5019                              VAR_DECL, DECL_NAME (adj->base),
5020                              TREE_TYPE (adj->base));
5021           if (DECL_PT_UID_SET_P (adj->base))
5022             SET_DECL_PT_UID (copy, DECL_PT_UID (adj->base));
5023           TREE_ADDRESSABLE (copy) = TREE_ADDRESSABLE (adj->base);
5024           TREE_READONLY (copy) = TREE_READONLY (adj->base);
5025           TREE_THIS_VOLATILE (copy) = TREE_THIS_VOLATILE (adj->base);
5026           DECL_GIMPLE_REG_P (copy) = DECL_GIMPLE_REG_P (adj->base);
5027           DECL_ARTIFICIAL (copy) = DECL_ARTIFICIAL (adj->base);
5028           DECL_IGNORED_P (copy) = DECL_IGNORED_P (adj->base);
5029           DECL_ABSTRACT_ORIGIN (copy) = DECL_ORIGIN (adj->base);
5030           DECL_SEEN_IN_BIND_EXPR_P (copy) = 1;
5031           SET_DECL_RTL (copy, 0);
5032           TREE_USED (copy) = 1;
5033           DECL_CONTEXT (copy) = current_function_decl;
5034           add_local_decl (cfun, copy);
5035           DECL_CHAIN (copy) =
5036             BLOCK_VARS (DECL_INITIAL (current_function_decl));
5037           BLOCK_VARS (DECL_INITIAL (current_function_decl)) = copy;
5038         }
5039       if (gsip != NULL && copy && target_for_debug_bind (adj->base))
5040         {
5041           gcc_assert (TREE_CODE (adj->base) == PARM_DECL);
5042           if (vexpr)
5043             def_temp = gimple_build_debug_bind (copy, vexpr, NULL);
5044           else
5045             def_temp = gimple_build_debug_source_bind (copy, adj->base,
5046                                                        NULL);
5047           gsi_insert_before (gsip, def_temp, GSI_SAME_STMT);
5048         }
5049     }
5050 }
5051
5052 /* Return false if all callers have at least as many actual arguments as there
5053    are formal parameters in the current function and that their types
5054    match.  */
5055
5056 static bool
5057 some_callers_have_mismatched_arguments_p (struct cgraph_node *node,
5058                                           void *data ATTRIBUTE_UNUSED)
5059 {
5060   struct cgraph_edge *cs;
5061   for (cs = node->callers; cs; cs = cs->next_caller)
5062     if (!cs->call_stmt || !callsite_arguments_match_p (cs->call_stmt))
5063       return true;
5064
5065   return false;
5066 }
5067
5068 /* Return false if all callers have vuse attached to a call statement.  */
5069
5070 static bool
5071 some_callers_have_no_vuse_p (struct cgraph_node *node,
5072                              void *data ATTRIBUTE_UNUSED)
5073 {
5074   struct cgraph_edge *cs;
5075   for (cs = node->callers; cs; cs = cs->next_caller)
5076     if (!cs->call_stmt || !gimple_vuse (cs->call_stmt))
5077       return true;
5078
5079   return false;
5080 }
5081
5082 /* Convert all callers of NODE.  */
5083
5084 static bool
5085 convert_callers_for_node (struct cgraph_node *node,
5086                           void *data)
5087 {
5088   ipa_parm_adjustment_vec *adjustments = (ipa_parm_adjustment_vec *) data;
5089   bitmap recomputed_callers = BITMAP_ALLOC (NULL);
5090   struct cgraph_edge *cs;
5091
5092   for (cs = node->callers; cs; cs = cs->next_caller)
5093     {
5094       push_cfun (DECL_STRUCT_FUNCTION (cs->caller->decl));
5095
5096       if (dump_file)
5097         fprintf (dump_file, "Adjusting call %s/%i -> %s/%i\n",
5098                  xstrdup_for_dump (cs->caller->name ()),
5099                  cs->caller->order,
5100                  xstrdup_for_dump (cs->callee->name ()),
5101                  cs->callee->order);
5102
5103       ipa_modify_call_arguments (cs, cs->call_stmt, *adjustments);
5104
5105       pop_cfun ();
5106     }
5107
5108   for (cs = node->callers; cs; cs = cs->next_caller)
5109     if (bitmap_set_bit (recomputed_callers, cs->caller->uid)
5110         && gimple_in_ssa_p (DECL_STRUCT_FUNCTION (cs->caller->decl)))
5111       compute_inline_parameters (cs->caller, true);
5112   BITMAP_FREE (recomputed_callers);
5113
5114   return true;
5115 }
5116
5117 /* Convert all callers of NODE to pass parameters as given in ADJUSTMENTS.  */
5118
5119 static void
5120 convert_callers (struct cgraph_node *node, tree old_decl,
5121                  ipa_parm_adjustment_vec adjustments)
5122 {
5123   basic_block this_block;
5124
5125   node->call_for_symbol_and_aliases (convert_callers_for_node,
5126                                      &adjustments, false);
5127
5128   if (!encountered_recursive_call)
5129     return;
5130
5131   FOR_EACH_BB_FN (this_block, cfun)
5132     {
5133       gimple_stmt_iterator gsi;
5134
5135       for (gsi = gsi_start_bb (this_block); !gsi_end_p (gsi); gsi_next (&gsi))
5136         {
5137           gcall *stmt;
5138           tree call_fndecl;
5139           stmt = dyn_cast <gcall *> (gsi_stmt (gsi));
5140           if (!stmt)
5141             continue;
5142           call_fndecl = gimple_call_fndecl (stmt);
5143           if (call_fndecl == old_decl)
5144             {
5145               if (dump_file)
5146                 fprintf (dump_file, "Adjusting recursive call");
5147               gimple_call_set_fndecl (stmt, node->decl);
5148               ipa_modify_call_arguments (NULL, stmt, adjustments);
5149             }
5150         }
5151     }
5152
5153   return;
5154 }
5155
5156 /* Perform all the modification required in IPA-SRA for NODE to have parameters
5157    as given in ADJUSTMENTS.  Return true iff the CFG has been changed.  */
5158
5159 static bool
5160 modify_function (struct cgraph_node *node, ipa_parm_adjustment_vec adjustments)
5161 {
5162   struct cgraph_node *new_node;
5163   bool cfg_changed;
5164
5165   cgraph_edge::rebuild_edges ();
5166   free_dominance_info (CDI_DOMINATORS);
5167   pop_cfun ();
5168
5169   /* This must be done after rebuilding cgraph edges for node above.
5170      Otherwise any recursive calls to node that are recorded in
5171      redirect_callers will be corrupted.  */
5172   vec<cgraph_edge *> redirect_callers = node->collect_callers ();
5173   new_node = node->create_version_clone_with_body (redirect_callers, NULL,
5174                                                    NULL, false, NULL, NULL,
5175                                                    "isra");
5176   redirect_callers.release ();
5177
5178   push_cfun (DECL_STRUCT_FUNCTION (new_node->decl));
5179   ipa_modify_formal_parameters (current_function_decl, adjustments);
5180   cfg_changed = ipa_sra_modify_function_body (adjustments);
5181   sra_ipa_reset_debug_stmts (adjustments);
5182   convert_callers (new_node, node->decl, adjustments);
5183   new_node->make_local ();
5184   return cfg_changed;
5185 }
5186
5187 /* Means of communication between ipa_sra_check_caller and
5188    ipa_sra_preliminary_function_checks.  */
5189
5190 struct ipa_sra_check_caller_data
5191 {
5192   bool has_callers;
5193   bool bad_arg_alignment;
5194   bool has_thunk;
5195 };
5196
5197 /* If NODE has a caller, mark that fact in DATA which is pointer to
5198    ipa_sra_check_caller_data.  Also check all aggregate arguments in all known
5199    calls if they are unit aligned and if not, set the appropriate flag in DATA
5200    too. */
5201
5202 static bool
5203 ipa_sra_check_caller (struct cgraph_node *node, void *data)
5204 {
5205   if (!node->callers)
5206     return false;
5207
5208   struct ipa_sra_check_caller_data *iscc;
5209   iscc = (struct ipa_sra_check_caller_data *) data;
5210   iscc->has_callers = true;
5211
5212   for (cgraph_edge *cs = node->callers; cs; cs = cs->next_caller)
5213     {
5214       if (cs->caller->thunk.thunk_p)
5215         {
5216           iscc->has_thunk = true;
5217           return true;
5218         }
5219       gimple *call_stmt = cs->call_stmt;
5220       unsigned count = gimple_call_num_args (call_stmt);
5221       for (unsigned i = 0; i < count; i++)
5222         {
5223           tree arg = gimple_call_arg (call_stmt, i);
5224           if (is_gimple_reg (arg))
5225               continue;
5226
5227           tree offset;
5228           HOST_WIDE_INT bitsize, bitpos;
5229           machine_mode mode;
5230           int unsignedp, reversep, volatilep = 0;
5231           get_inner_reference (arg, &bitsize, &bitpos, &offset, &mode,
5232                                &unsignedp, &reversep, &volatilep);
5233           if (bitpos % BITS_PER_UNIT)
5234             {
5235               iscc->bad_arg_alignment = true;
5236               return true;
5237             }
5238         }
5239     }
5240
5241   return false;
5242 }
5243
5244 /* Return false the function is apparently unsuitable for IPA-SRA based on it's
5245    attributes, return true otherwise.  NODE is the cgraph node of the current
5246    function.  */
5247
5248 static bool
5249 ipa_sra_preliminary_function_checks (struct cgraph_node *node)
5250 {
5251   if (!node->can_be_local_p ())
5252     {
5253       if (dump_file)
5254         fprintf (dump_file, "Function not local to this compilation unit.\n");
5255       return false;
5256     }
5257
5258   if (!node->local.can_change_signature)
5259     {
5260       if (dump_file)
5261         fprintf (dump_file, "Function can not change signature.\n");
5262       return false;
5263     }
5264
5265   if (!tree_versionable_function_p (node->decl))
5266     {
5267       if (dump_file)
5268         fprintf (dump_file, "Function is not versionable.\n");
5269       return false;
5270     }
5271
5272   if (!opt_for_fn (node->decl, optimize)
5273       || !opt_for_fn (node->decl, flag_ipa_sra))
5274     {
5275       if (dump_file)
5276         fprintf (dump_file, "Function not optimized.\n");
5277       return false;
5278     }
5279
5280   if (DECL_VIRTUAL_P (current_function_decl))
5281     {
5282       if (dump_file)
5283         fprintf (dump_file, "Function is a virtual method.\n");
5284       return false;
5285     }
5286
5287   if ((DECL_ONE_ONLY (node->decl) || DECL_EXTERNAL (node->decl))
5288       && inline_summaries->get (node)->size >= MAX_INLINE_INSNS_AUTO)
5289     {
5290       if (dump_file)
5291         fprintf (dump_file, "Function too big to be made truly local.\n");
5292       return false;
5293     }
5294
5295   if (cfun->stdarg)
5296     {
5297       if (dump_file)
5298         fprintf (dump_file, "Function uses stdarg. \n");
5299       return false;
5300     }
5301
5302   if (TYPE_ATTRIBUTES (TREE_TYPE (node->decl)))
5303     return false;
5304
5305   if (DECL_DISREGARD_INLINE_LIMITS (node->decl))
5306     {
5307       if (dump_file)
5308         fprintf (dump_file, "Always inline function will be inlined "
5309                  "anyway. \n");
5310       return false;
5311     }
5312
5313   struct ipa_sra_check_caller_data iscc;
5314   memset (&iscc, 0, sizeof(iscc));
5315   node->call_for_symbol_and_aliases (ipa_sra_check_caller, &iscc, true);
5316   if (!iscc.has_callers)
5317     {
5318       if (dump_file)
5319         fprintf (dump_file,
5320                  "Function has no callers in this compilation unit.\n");
5321       return false;
5322     }
5323
5324   if (iscc.bad_arg_alignment)
5325     {
5326       if (dump_file)
5327         fprintf (dump_file,
5328                  "A function call has an argument with non-unit alignment.\n");
5329       return false;
5330     }
5331
5332   if (iscc.has_thunk)
5333     {
5334       if (dump_file)
5335         fprintf (dump_file,
5336                  "A has thunk.\n");
5337       return false;
5338     }
5339
5340   return true;
5341 }
5342
5343 /* Perform early interprocedural SRA.  */
5344
5345 static unsigned int
5346 ipa_early_sra (void)
5347 {
5348   struct cgraph_node *node = cgraph_node::get (current_function_decl);
5349   ipa_parm_adjustment_vec adjustments;
5350   int ret = 0;
5351
5352   if (!ipa_sra_preliminary_function_checks (node))
5353     return 0;
5354
5355   sra_initialize ();
5356   sra_mode = SRA_MODE_EARLY_IPA;
5357
5358   if (!find_param_candidates ())
5359     {
5360       if (dump_file)
5361         fprintf (dump_file, "Function has no IPA-SRA candidates.\n");
5362       goto simple_out;
5363     }
5364
5365   if (node->call_for_symbol_and_aliases
5366        (some_callers_have_mismatched_arguments_p, NULL, true))
5367     {
5368       if (dump_file)
5369         fprintf (dump_file, "There are callers with insufficient number of "
5370                  "arguments or arguments with type mismatches.\n");
5371       goto simple_out;
5372     }
5373
5374   if (node->call_for_symbol_and_aliases
5375        (some_callers_have_no_vuse_p, NULL, true))
5376     {
5377       if (dump_file)
5378         fprintf (dump_file, "There are callers with no VUSE attached "
5379                  "to a call stmt.\n");
5380       goto simple_out;
5381     }
5382
5383   bb_dereferences = XCNEWVEC (HOST_WIDE_INT,
5384                                  func_param_count
5385                                  * last_basic_block_for_fn (cfun));
5386   final_bbs = BITMAP_ALLOC (NULL);
5387
5388   scan_function ();
5389   if (encountered_apply_args)
5390     {
5391       if (dump_file)
5392         fprintf (dump_file, "Function calls  __builtin_apply_args().\n");
5393       goto out;
5394     }
5395
5396   if (encountered_unchangable_recursive_call)
5397     {
5398       if (dump_file)
5399         fprintf (dump_file, "Function calls itself with insufficient "
5400                  "number of arguments.\n");
5401       goto out;
5402     }
5403
5404   adjustments = analyze_all_param_acesses ();
5405   if (!adjustments.exists ())
5406     goto out;
5407   if (dump_file)
5408     ipa_dump_param_adjustments (dump_file, adjustments, current_function_decl);
5409
5410   if (modify_function (node, adjustments))
5411     ret = TODO_update_ssa | TODO_cleanup_cfg;
5412   else
5413     ret = TODO_update_ssa;
5414   adjustments.release ();
5415
5416   statistics_counter_event (cfun, "Unused parameters deleted",
5417                             sra_stats.deleted_unused_parameters);
5418   statistics_counter_event (cfun, "Scalar parameters converted to by-value",
5419                             sra_stats.scalar_by_ref_to_by_val);
5420   statistics_counter_event (cfun, "Aggregate parameters broken up",
5421                             sra_stats.aggregate_params_reduced);
5422   statistics_counter_event (cfun, "Aggregate parameter components created",
5423                             sra_stats.param_reductions_created);
5424
5425  out:
5426   BITMAP_FREE (final_bbs);
5427   free (bb_dereferences);
5428  simple_out:
5429   sra_deinitialize ();
5430   return ret;
5431 }
5432
5433 namespace {
5434
5435 const pass_data pass_data_early_ipa_sra =
5436 {
5437   GIMPLE_PASS, /* type */
5438   "eipa_sra", /* name */
5439   OPTGROUP_NONE, /* optinfo_flags */
5440   TV_IPA_SRA, /* tv_id */
5441   0, /* properties_required */
5442   0, /* properties_provided */
5443   0, /* properties_destroyed */
5444   0, /* todo_flags_start */
5445   TODO_dump_symtab, /* todo_flags_finish */
5446 };
5447
5448 class pass_early_ipa_sra : public gimple_opt_pass
5449 {
5450 public:
5451   pass_early_ipa_sra (gcc::context *ctxt)
5452     : gimple_opt_pass (pass_data_early_ipa_sra, ctxt)
5453   {}
5454
5455   /* opt_pass methods: */
5456   virtual bool gate (function *) { return flag_ipa_sra && dbg_cnt (eipa_sra); }
5457   virtual unsigned int execute (function *) { return ipa_early_sra (); }
5458
5459 }; // class pass_early_ipa_sra
5460
5461 } // anon namespace
5462
5463 gimple_opt_pass *
5464 make_pass_early_ipa_sra (gcc::context *ctxt)
5465 {
5466   return new pass_early_ipa_sra (ctxt);
5467 }