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) 2008-2016 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 TREE_CODE (decl) == VAR_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; wi::les_p (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 (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 = (misalign & -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 (TREE_CODE (var) != VAR_DECL)
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 = multiple_scalar_reads || total_scalarization;
2078       access->grp_total_scalarization = total_scalarization;
2079       access->grp_partial_lhs = grp_partial_lhs;
2080       access->grp_unscalarizable_region = unscalarizable_region;
2081       if (access->first_link)
2082         add_access_to_work_queue (access);
2083
2084       *prev_acc_ptr = access;
2085       prev_acc_ptr = &access->next_grp;
2086     }
2087
2088   gcc_assert (res == (*access_vec)[0]);
2089   return res;
2090 }
2091
2092 /* Create a variable for the given ACCESS which determines the type, name and a
2093    few other properties.  Return the variable declaration and store it also to
2094    ACCESS->replacement.  */
2095
2096 static tree
2097 create_access_replacement (struct access *access)
2098 {
2099   tree repl;
2100
2101   if (access->grp_to_be_debug_replaced)
2102     {
2103       repl = create_tmp_var_raw (access->type);
2104       DECL_CONTEXT (repl) = current_function_decl;
2105     }
2106   else
2107     /* Drop any special alignment on the type if it's not on the main
2108        variant.  This avoids issues with weirdo ABIs like AAPCS.  */
2109     repl = create_tmp_var (build_qualified_type
2110                              (TYPE_MAIN_VARIANT (access->type),
2111                               TYPE_QUALS (access->type)), "SR");
2112   if (TREE_CODE (access->type) == COMPLEX_TYPE
2113       || TREE_CODE (access->type) == VECTOR_TYPE)
2114     {
2115       if (!access->grp_partial_lhs)
2116         DECL_GIMPLE_REG_P (repl) = 1;
2117     }
2118   else if (access->grp_partial_lhs
2119            && is_gimple_reg_type (access->type))
2120     TREE_ADDRESSABLE (repl) = 1;
2121
2122   DECL_SOURCE_LOCATION (repl) = DECL_SOURCE_LOCATION (access->base);
2123   DECL_ARTIFICIAL (repl) = 1;
2124   DECL_IGNORED_P (repl) = DECL_IGNORED_P (access->base);
2125
2126   if (DECL_NAME (access->base)
2127       && !DECL_IGNORED_P (access->base)
2128       && !DECL_ARTIFICIAL (access->base))
2129     {
2130       char *pretty_name = make_fancy_name (access->expr);
2131       tree debug_expr = unshare_expr_without_location (access->expr), d;
2132       bool fail = false;
2133
2134       DECL_NAME (repl) = get_identifier (pretty_name);
2135       obstack_free (&name_obstack, pretty_name);
2136
2137       /* Get rid of any SSA_NAMEs embedded in debug_expr,
2138          as DECL_DEBUG_EXPR isn't considered when looking for still
2139          used SSA_NAMEs and thus they could be freed.  All debug info
2140          generation cares is whether something is constant or variable
2141          and that get_ref_base_and_extent works properly on the
2142          expression.  It cannot handle accesses at a non-constant offset
2143          though, so just give up in those cases.  */
2144       for (d = debug_expr;
2145            !fail && (handled_component_p (d) || TREE_CODE (d) == MEM_REF);
2146            d = TREE_OPERAND (d, 0))
2147         switch (TREE_CODE (d))
2148           {
2149           case ARRAY_REF:
2150           case ARRAY_RANGE_REF:
2151             if (TREE_OPERAND (d, 1)
2152                 && TREE_CODE (TREE_OPERAND (d, 1)) != INTEGER_CST)
2153               fail = true;
2154             if (TREE_OPERAND (d, 3)
2155                 && TREE_CODE (TREE_OPERAND (d, 3)) != INTEGER_CST)
2156               fail = true;
2157             /* FALLTHRU */
2158           case COMPONENT_REF:
2159             if (TREE_OPERAND (d, 2)
2160                 && TREE_CODE (TREE_OPERAND (d, 2)) != INTEGER_CST)
2161               fail = true;
2162             break;
2163           case MEM_REF:
2164             if (TREE_CODE (TREE_OPERAND (d, 0)) != ADDR_EXPR)
2165               fail = true;
2166             else
2167               d = TREE_OPERAND (d, 0);
2168             break;
2169           default:
2170             break;
2171           }
2172       if (!fail)
2173         {
2174           SET_DECL_DEBUG_EXPR (repl, debug_expr);
2175           DECL_HAS_DEBUG_EXPR_P (repl) = 1;
2176         }
2177       if (access->grp_no_warning)
2178         TREE_NO_WARNING (repl) = 1;
2179       else
2180         TREE_NO_WARNING (repl) = TREE_NO_WARNING (access->base);
2181     }
2182   else
2183     TREE_NO_WARNING (repl) = 1;
2184
2185   if (dump_file)
2186     {
2187       if (access->grp_to_be_debug_replaced)
2188         {
2189           fprintf (dump_file, "Created a debug-only replacement for ");
2190           print_generic_expr (dump_file, access->base, 0);
2191           fprintf (dump_file, " offset: %u, size: %u\n",
2192                    (unsigned) access->offset, (unsigned) access->size);
2193         }
2194       else
2195         {
2196           fprintf (dump_file, "Created a replacement for ");
2197           print_generic_expr (dump_file, access->base, 0);
2198           fprintf (dump_file, " offset: %u, size: %u: ",
2199                    (unsigned) access->offset, (unsigned) access->size);
2200           print_generic_expr (dump_file, repl, 0);
2201           fprintf (dump_file, "\n");
2202         }
2203     }
2204   sra_stats.replacements++;
2205
2206   return repl;
2207 }
2208
2209 /* Return ACCESS scalar replacement, which must exist.  */
2210
2211 static inline tree
2212 get_access_replacement (struct access *access)
2213 {
2214   gcc_checking_assert (access->replacement_decl);
2215   return access->replacement_decl;
2216 }
2217
2218
2219 /* Build a subtree of accesses rooted in *ACCESS, and move the pointer in the
2220    linked list along the way.  Stop when *ACCESS is NULL or the access pointed
2221    to it is not "within" the root.  Return false iff some accesses partially
2222    overlap.  */
2223
2224 static bool
2225 build_access_subtree (struct access **access)
2226 {
2227   struct access *root = *access, *last_child = NULL;
2228   HOST_WIDE_INT limit = root->offset + root->size;
2229
2230   *access = (*access)->next_grp;
2231   while  (*access && (*access)->offset + (*access)->size <= limit)
2232     {
2233       if (!last_child)
2234         root->first_child = *access;
2235       else
2236         last_child->next_sibling = *access;
2237       last_child = *access;
2238
2239       if (!build_access_subtree (access))
2240         return false;
2241     }
2242
2243   if (*access && (*access)->offset < limit)
2244     return false;
2245
2246   return true;
2247 }
2248
2249 /* Build a tree of access representatives, ACCESS is the pointer to the first
2250    one, others are linked in a list by the next_grp field.  Return false iff
2251    some accesses partially overlap.  */
2252
2253 static bool
2254 build_access_trees (struct access *access)
2255 {
2256   while (access)
2257     {
2258       struct access *root = access;
2259
2260       if (!build_access_subtree (&access))
2261         return false;
2262       root->next_grp = access;
2263     }
2264   return true;
2265 }
2266
2267 /* Return true if expr contains some ARRAY_REFs into a variable bounded
2268    array.  */
2269
2270 static bool
2271 expr_with_var_bounded_array_refs_p (tree expr)
2272 {
2273   while (handled_component_p (expr))
2274     {
2275       if (TREE_CODE (expr) == ARRAY_REF
2276           && !tree_fits_shwi_p (array_ref_low_bound (expr)))
2277         return true;
2278       expr = TREE_OPERAND (expr, 0);
2279     }
2280   return false;
2281 }
2282
2283 /* Analyze the subtree of accesses rooted in ROOT, scheduling replacements when
2284    both seeming beneficial and when ALLOW_REPLACEMENTS allows it.  Also set all
2285    sorts of access flags appropriately along the way, notably always set
2286    grp_read and grp_assign_read according to MARK_READ and grp_write when
2287    MARK_WRITE is true.
2288
2289    Creating a replacement for a scalar access is considered beneficial if its
2290    grp_hint is set (this means we are either attempting total scalarization or
2291    there is more than one direct read access) or according to the following
2292    table:
2293
2294    Access written to through a scalar type (once or more times)
2295    |
2296    |    Written to in an assignment statement
2297    |    |
2298    |    |       Access read as scalar _once_
2299    |    |       |
2300    |    |       |       Read in an assignment statement
2301    |    |       |       |
2302    |    |       |       |       Scalarize       Comment
2303 -----------------------------------------------------------------------------
2304    0    0       0       0                       No access for the scalar
2305    0    0       0       1                       No access for the scalar
2306    0    0       1       0       No              Single read - won't help
2307    0    0       1       1       No              The same case
2308    0    1       0       0                       No access for the scalar
2309    0    1       0       1                       No access for the scalar
2310    0    1       1       0       Yes             s = *g; return s.i;
2311    0    1       1       1       Yes             The same case as above
2312    1    0       0       0       No              Won't help
2313    1    0       0       1       Yes             s.i = 1; *g = s;
2314    1    0       1       0       Yes             s.i = 5; g = s.i;
2315    1    0       1       1       Yes             The same case as above
2316    1    1       0       0       No              Won't help.
2317    1    1       0       1       Yes             s.i = 1; *g = s;
2318    1    1       1       0       Yes             s = *g; return s.i;
2319    1    1       1       1       Yes             Any of the above yeses  */
2320
2321 static bool
2322 analyze_access_subtree (struct access *root, struct access *parent,
2323                         bool allow_replacements)
2324 {
2325   struct access *child;
2326   HOST_WIDE_INT limit = root->offset + root->size;
2327   HOST_WIDE_INT covered_to = root->offset;
2328   bool scalar = is_gimple_reg_type (root->type);
2329   bool hole = false, sth_created = false;
2330
2331   if (parent)
2332     {
2333       if (parent->grp_read)
2334         root->grp_read = 1;
2335       if (parent->grp_assignment_read)
2336         root->grp_assignment_read = 1;
2337       if (parent->grp_write)
2338         root->grp_write = 1;
2339       if (parent->grp_assignment_write)
2340         root->grp_assignment_write = 1;
2341       if (parent->grp_total_scalarization)
2342         root->grp_total_scalarization = 1;
2343     }
2344
2345   if (root->grp_unscalarizable_region)
2346     allow_replacements = false;
2347
2348   if (allow_replacements && expr_with_var_bounded_array_refs_p (root->expr))
2349     allow_replacements = false;
2350
2351   for (child = root->first_child; child; child = child->next_sibling)
2352     {
2353       hole |= covered_to < child->offset;
2354       sth_created |= analyze_access_subtree (child, root,
2355                                              allow_replacements && !scalar);
2356
2357       root->grp_unscalarized_data |= child->grp_unscalarized_data;
2358       root->grp_total_scalarization &= child->grp_total_scalarization;
2359       if (child->grp_covered)
2360         covered_to += child->size;
2361       else
2362         hole = true;
2363     }
2364
2365   if (allow_replacements && scalar && !root->first_child
2366       && (root->grp_hint
2367           || ((root->grp_scalar_read || root->grp_assignment_read)
2368               && (root->grp_scalar_write || root->grp_assignment_write))))
2369     {
2370       /* Always create access replacements that cover the whole access.
2371          For integral types this means the precision has to match.
2372          Avoid assumptions based on the integral type kind, too.  */
2373       if (INTEGRAL_TYPE_P (root->type)
2374           && (TREE_CODE (root->type) != INTEGER_TYPE
2375               || TYPE_PRECISION (root->type) != root->size)
2376           /* But leave bitfield accesses alone.  */
2377           && (TREE_CODE (root->expr) != COMPONENT_REF
2378               || !DECL_BIT_FIELD (TREE_OPERAND (root->expr, 1))))
2379         {
2380           tree rt = root->type;
2381           gcc_assert ((root->offset % BITS_PER_UNIT) == 0
2382                       && (root->size % BITS_PER_UNIT) == 0);
2383           root->type = build_nonstandard_integer_type (root->size,
2384                                                        TYPE_UNSIGNED (rt));
2385           root->expr = build_ref_for_offset (UNKNOWN_LOCATION, root->base,
2386                                              root->offset, root->reverse,
2387                                              root->type, NULL, false);
2388
2389           if (dump_file && (dump_flags & TDF_DETAILS))
2390             {
2391               fprintf (dump_file, "Changing the type of a replacement for ");
2392               print_generic_expr (dump_file, root->base, 0);
2393               fprintf (dump_file, " offset: %u, size: %u ",
2394                        (unsigned) root->offset, (unsigned) root->size);
2395               fprintf (dump_file, " to an integer.\n");
2396             }
2397         }
2398
2399       root->grp_to_be_replaced = 1;
2400       root->replacement_decl = create_access_replacement (root);
2401       sth_created = true;
2402       hole = false;
2403     }
2404   else
2405     {
2406       if (allow_replacements
2407           && scalar && !root->first_child
2408           && (root->grp_scalar_write || root->grp_assignment_write)
2409           && !bitmap_bit_p (cannot_scalarize_away_bitmap,
2410                             DECL_UID (root->base)))
2411         {
2412           gcc_checking_assert (!root->grp_scalar_read
2413                                && !root->grp_assignment_read);
2414           sth_created = true;
2415           if (MAY_HAVE_DEBUG_STMTS)
2416             {
2417               root->grp_to_be_debug_replaced = 1;
2418               root->replacement_decl = create_access_replacement (root);
2419             }
2420         }
2421
2422       if (covered_to < limit)
2423         hole = true;
2424       if (scalar || !allow_replacements)
2425         root->grp_total_scalarization = 0;
2426     }
2427
2428   if (!hole || root->grp_total_scalarization)
2429     root->grp_covered = 1;
2430   else if (root->grp_write || TREE_CODE (root->base) == PARM_DECL)
2431     root->grp_unscalarized_data = 1; /* not covered and written to */
2432   return sth_created;
2433 }
2434
2435 /* Analyze all access trees linked by next_grp by the means of
2436    analyze_access_subtree.  */
2437 static bool
2438 analyze_access_trees (struct access *access)
2439 {
2440   bool ret = false;
2441
2442   while (access)
2443     {
2444       if (analyze_access_subtree (access, NULL, true))
2445         ret = true;
2446       access = access->next_grp;
2447     }
2448
2449   return ret;
2450 }
2451
2452 /* Return true iff a potential new child of LACC at offset OFFSET and with size
2453    SIZE would conflict with an already existing one.  If exactly such a child
2454    already exists in LACC, store a pointer to it in EXACT_MATCH.  */
2455
2456 static bool
2457 child_would_conflict_in_lacc (struct access *lacc, HOST_WIDE_INT norm_offset,
2458                               HOST_WIDE_INT size, struct access **exact_match)
2459 {
2460   struct access *child;
2461
2462   for (child = lacc->first_child; child; child = child->next_sibling)
2463     {
2464       if (child->offset == norm_offset && child->size == size)
2465         {
2466           *exact_match = child;
2467           return true;
2468         }
2469
2470       if (child->offset < norm_offset + size
2471           && child->offset + child->size > norm_offset)
2472         return true;
2473     }
2474
2475   return false;
2476 }
2477
2478 /* Create a new child access of PARENT, with all properties just like MODEL
2479    except for its offset and with its grp_write false and grp_read true.
2480    Return the new access or NULL if it cannot be created.  Note that this access
2481    is created long after all splicing and sorting, it's not located in any
2482    access vector and is automatically a representative of its group.  */
2483
2484 static struct access *
2485 create_artificial_child_access (struct access *parent, struct access *model,
2486                                 HOST_WIDE_INT new_offset)
2487 {
2488   struct access **child;
2489   tree expr = parent->base;
2490
2491   gcc_assert (!model->grp_unscalarizable_region);
2492
2493   struct access *access = access_pool.allocate ();
2494   memset (access, 0, sizeof (struct access));
2495   if (!build_user_friendly_ref_for_offset (&expr, TREE_TYPE (expr), new_offset,
2496                                            model->type))
2497     {
2498       access->grp_no_warning = true;
2499       expr = build_ref_for_model (EXPR_LOCATION (parent->base), parent->base,
2500                                   new_offset, model, NULL, false);
2501     }
2502
2503   access->base = parent->base;
2504   access->expr = expr;
2505   access->offset = new_offset;
2506   access->size = model->size;
2507   access->type = model->type;
2508   access->grp_write = true;
2509   access->grp_read = false;
2510   access->reverse = model->reverse;
2511
2512   child = &parent->first_child;
2513   while (*child && (*child)->offset < new_offset)
2514     child = &(*child)->next_sibling;
2515
2516   access->next_sibling = *child;
2517   *child = access;
2518
2519   return access;
2520 }
2521
2522
2523 /* Propagate all subaccesses of RACC across an assignment link to LACC. Return
2524    true if any new subaccess was created.  Additionally, if RACC is a scalar
2525    access but LACC is not, change the type of the latter, if possible.  */
2526
2527 static bool
2528 propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
2529 {
2530   struct access *rchild;
2531   HOST_WIDE_INT norm_delta = lacc->offset - racc->offset;
2532   bool ret = false;
2533
2534   if (is_gimple_reg_type (lacc->type)
2535       || lacc->grp_unscalarizable_region
2536       || racc->grp_unscalarizable_region)
2537     return false;
2538
2539   if (is_gimple_reg_type (racc->type))
2540     {
2541       if (!lacc->first_child && !racc->first_child)
2542         {
2543           tree t = lacc->base;
2544
2545           lacc->type = racc->type;
2546           if (build_user_friendly_ref_for_offset (&t, TREE_TYPE (t),
2547                                                   lacc->offset, racc->type))
2548             lacc->expr = t;
2549           else
2550             {
2551               lacc->expr = build_ref_for_model (EXPR_LOCATION (lacc->base),
2552                                                 lacc->base, lacc->offset,
2553                                                 racc, NULL, false);
2554               lacc->grp_no_warning = true;
2555             }
2556         }
2557       return false;
2558     }
2559
2560   for (rchild = racc->first_child; rchild; rchild = rchild->next_sibling)
2561     {
2562       struct access *new_acc = NULL;
2563       HOST_WIDE_INT norm_offset = rchild->offset + norm_delta;
2564
2565       if (rchild->grp_unscalarizable_region)
2566         continue;
2567
2568       if (child_would_conflict_in_lacc (lacc, norm_offset, rchild->size,
2569                                         &new_acc))
2570         {
2571           if (new_acc)
2572             {
2573               rchild->grp_hint = 1;
2574               new_acc->grp_hint |= new_acc->grp_read;
2575               if (rchild->first_child)
2576                 ret |= propagate_subaccesses_across_link (new_acc, rchild);
2577             }
2578           continue;
2579         }
2580
2581       rchild->grp_hint = 1;
2582       new_acc = create_artificial_child_access (lacc, rchild, norm_offset);
2583       if (new_acc)
2584         {
2585           ret = true;
2586           if (racc->first_child)
2587             propagate_subaccesses_across_link (new_acc, rchild);
2588         }
2589     }
2590
2591   return ret;
2592 }
2593
2594 /* Propagate all subaccesses across assignment links.  */
2595
2596 static void
2597 propagate_all_subaccesses (void)
2598 {
2599   while (work_queue_head)
2600     {
2601       struct access *racc = pop_access_from_work_queue ();
2602       struct assign_link *link;
2603
2604       gcc_assert (racc->first_link);
2605
2606       for (link = racc->first_link; link; link = link->next)
2607         {
2608           struct access *lacc = link->lacc;
2609
2610           if (!bitmap_bit_p (candidate_bitmap, DECL_UID (lacc->base)))
2611             continue;
2612           lacc = lacc->group_representative;
2613           if (propagate_subaccesses_across_link (lacc, racc)
2614               && lacc->first_link)
2615             add_access_to_work_queue (lacc);
2616         }
2617     }
2618 }
2619
2620 /* Go through all accesses collected throughout the (intraprocedural) analysis
2621    stage, exclude overlapping ones, identify representatives and build trees
2622    out of them, making decisions about scalarization on the way.  Return true
2623    iff there are any to-be-scalarized variables after this stage. */
2624
2625 static bool
2626 analyze_all_variable_accesses (void)
2627 {
2628   int res = 0;
2629   bitmap tmp = BITMAP_ALLOC (NULL);
2630   bitmap_iterator bi;
2631   unsigned i;
2632   bool optimize_speed_p = !optimize_function_for_size_p (cfun);
2633
2634   enum compiler_param param = optimize_speed_p
2635                         ? PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED
2636                         : PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE;
2637
2638   /* If the user didn't set PARAM_SRA_MAX_SCALARIZATION_SIZE_<...>,
2639      fall back to a target default.  */
2640   unsigned HOST_WIDE_INT max_scalarization_size
2641     = global_options_set.x_param_values[param]
2642       ? PARAM_VALUE (param)
2643       : get_move_ratio (optimize_speed_p) * UNITS_PER_WORD;
2644
2645   max_scalarization_size *= BITS_PER_UNIT;
2646
2647   EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
2648     if (bitmap_bit_p (should_scalarize_away_bitmap, i)
2649         && !bitmap_bit_p (cannot_scalarize_away_bitmap, i))
2650       {
2651         tree var = candidate (i);
2652
2653         if (TREE_CODE (var) == VAR_DECL
2654             && scalarizable_type_p (TREE_TYPE (var)))
2655           {
2656             if (tree_to_uhwi (TYPE_SIZE (TREE_TYPE (var)))
2657                 <= max_scalarization_size)
2658               {
2659                 create_total_scalarization_access (var);
2660                 completely_scalarize (var, TREE_TYPE (var), 0, var);
2661                 if (dump_file && (dump_flags & TDF_DETAILS))
2662                   {
2663                     fprintf (dump_file, "Will attempt to totally scalarize ");
2664                     print_generic_expr (dump_file, var, 0);
2665                     fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2666                   }
2667               }
2668             else if (dump_file && (dump_flags & TDF_DETAILS))
2669               {
2670                 fprintf (dump_file, "Too big to totally scalarize: ");
2671                 print_generic_expr (dump_file, var, 0);
2672                 fprintf (dump_file, " (UID: %u)\n", DECL_UID (var));
2673               }
2674           }
2675       }
2676
2677   bitmap_copy (tmp, candidate_bitmap);
2678   EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2679     {
2680       tree var = candidate (i);
2681       struct access *access;
2682
2683       access = sort_and_splice_var_accesses (var);
2684       if (!access || !build_access_trees (access))
2685         disqualify_candidate (var,
2686                               "No or inhibitingly overlapping accesses.");
2687     }
2688
2689   propagate_all_subaccesses ();
2690
2691   bitmap_copy (tmp, candidate_bitmap);
2692   EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2693     {
2694       tree var = candidate (i);
2695       struct access *access = get_first_repr_for_decl (var);
2696
2697       if (analyze_access_trees (access))
2698         {
2699           res++;
2700           if (dump_file && (dump_flags & TDF_DETAILS))
2701             {
2702               fprintf (dump_file, "\nAccess trees for ");
2703               print_generic_expr (dump_file, var, 0);
2704               fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2705               dump_access_tree (dump_file, access);
2706               fprintf (dump_file, "\n");
2707             }
2708         }
2709       else
2710         disqualify_candidate (var, "No scalar replacements to be created.");
2711     }
2712
2713   BITMAP_FREE (tmp);
2714
2715   if (res)
2716     {
2717       statistics_counter_event (cfun, "Scalarized aggregates", res);
2718       return true;
2719     }
2720   else
2721     return false;
2722 }
2723
2724 /* Generate statements copying scalar replacements of accesses within a subtree
2725    into or out of AGG.  ACCESS, all its children, siblings and their children
2726    are to be processed.  AGG is an aggregate type expression (can be a
2727    declaration but does not have to be, it can for example also be a mem_ref or
2728    a series of handled components).  TOP_OFFSET is the offset of the processed
2729    subtree which has to be subtracted from offsets of individual accesses to
2730    get corresponding offsets for AGG.  If CHUNK_SIZE is non-null, copy only
2731    replacements in the interval <start_offset, start_offset + chunk_size>,
2732    otherwise copy all.  GSI is a statement iterator used to place the new
2733    statements.  WRITE should be true when the statements should write from AGG
2734    to the replacement and false if vice versa.  if INSERT_AFTER is true, new
2735    statements will be added after the current statement in GSI, they will be
2736    added before the statement otherwise.  */
2737
2738 static void
2739 generate_subtree_copies (struct access *access, tree agg,
2740                          HOST_WIDE_INT top_offset,
2741                          HOST_WIDE_INT start_offset, HOST_WIDE_INT chunk_size,
2742                          gimple_stmt_iterator *gsi, bool write,
2743                          bool insert_after, location_t loc)
2744 {
2745   do
2746     {
2747       if (chunk_size && access->offset >= start_offset + chunk_size)
2748         return;
2749
2750       if (access->grp_to_be_replaced
2751           && (chunk_size == 0
2752               || access->offset + access->size > start_offset))
2753         {
2754           tree expr, repl = get_access_replacement (access);
2755           gassign *stmt;
2756
2757           expr = build_ref_for_model (loc, agg, access->offset - top_offset,
2758                                       access, gsi, insert_after);
2759
2760           if (write)
2761             {
2762               if (access->grp_partial_lhs)
2763                 expr = force_gimple_operand_gsi (gsi, expr, true, NULL_TREE,
2764                                                  !insert_after,
2765                                                  insert_after ? GSI_NEW_STMT
2766                                                  : GSI_SAME_STMT);
2767               stmt = gimple_build_assign (repl, expr);
2768             }
2769           else
2770             {
2771               TREE_NO_WARNING (repl) = 1;
2772               if (access->grp_partial_lhs)
2773                 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
2774                                                  !insert_after,
2775                                                  insert_after ? GSI_NEW_STMT
2776                                                  : GSI_SAME_STMT);
2777               stmt = gimple_build_assign (expr, repl);
2778             }
2779           gimple_set_location (stmt, loc);
2780
2781           if (insert_after)
2782             gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2783           else
2784             gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2785           update_stmt (stmt);
2786           sra_stats.subtree_copies++;
2787         }
2788       else if (write
2789                && access->grp_to_be_debug_replaced
2790                && (chunk_size == 0
2791                    || access->offset + access->size > start_offset))
2792         {
2793           gdebug *ds;
2794           tree drhs = build_debug_ref_for_model (loc, agg,
2795                                                  access->offset - top_offset,
2796                                                  access);
2797           ds = gimple_build_debug_bind (get_access_replacement (access),
2798                                         drhs, gsi_stmt (*gsi));
2799           if (insert_after)
2800             gsi_insert_after (gsi, ds, GSI_NEW_STMT);
2801           else
2802             gsi_insert_before (gsi, ds, GSI_SAME_STMT);
2803         }
2804
2805       if (access->first_child)
2806         generate_subtree_copies (access->first_child, agg, top_offset,
2807                                  start_offset, chunk_size, gsi,
2808                                  write, insert_after, loc);
2809
2810       access = access->next_sibling;
2811     }
2812   while (access);
2813 }
2814
2815 /* Assign zero to all scalar replacements in an access subtree.  ACCESS is the
2816    root of the subtree to be processed.  GSI is the statement iterator used
2817    for inserting statements which are added after the current statement if
2818    INSERT_AFTER is true or before it otherwise.  */
2819
2820 static void
2821 init_subtree_with_zero (struct access *access, gimple_stmt_iterator *gsi,
2822                         bool insert_after, location_t loc)
2823
2824 {
2825   struct access *child;
2826
2827   if (access->grp_to_be_replaced)
2828     {
2829       gassign *stmt;
2830
2831       stmt = gimple_build_assign (get_access_replacement (access),
2832                                   build_zero_cst (access->type));
2833       if (insert_after)
2834         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2835       else
2836         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2837       update_stmt (stmt);
2838       gimple_set_location (stmt, loc);
2839     }
2840   else if (access->grp_to_be_debug_replaced)
2841     {
2842       gdebug *ds
2843         = gimple_build_debug_bind (get_access_replacement (access),
2844                                    build_zero_cst (access->type),
2845                                    gsi_stmt (*gsi));
2846       if (insert_after)
2847         gsi_insert_after (gsi, ds, GSI_NEW_STMT);
2848       else
2849         gsi_insert_before (gsi, ds, GSI_SAME_STMT);
2850     }
2851
2852   for (child = access->first_child; child; child = child->next_sibling)
2853     init_subtree_with_zero (child, gsi, insert_after, loc);
2854 }
2855
2856 /* Clobber all scalar replacements in an access subtree.  ACCESS is the
2857    root of the subtree to be processed.  GSI is the statement iterator used
2858    for inserting statements which are added after the current statement if
2859    INSERT_AFTER is true or before it otherwise.  */
2860
2861 static void
2862 clobber_subtree (struct access *access, gimple_stmt_iterator *gsi,
2863                 bool insert_after, location_t loc)
2864
2865 {
2866   struct access *child;
2867
2868   if (access->grp_to_be_replaced)
2869     {
2870       tree rep = get_access_replacement (access);
2871       tree clobber = build_constructor (access->type, NULL);
2872       TREE_THIS_VOLATILE (clobber) = 1;
2873       gimple *stmt = gimple_build_assign (rep, clobber);
2874
2875       if (insert_after)
2876         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2877       else
2878         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2879       update_stmt (stmt);
2880       gimple_set_location (stmt, loc);
2881     }
2882
2883   for (child = access->first_child; child; child = child->next_sibling)
2884     clobber_subtree (child, gsi, insert_after, loc);
2885 }
2886
2887 /* Search for an access representative for the given expression EXPR and
2888    return it or NULL if it cannot be found.  */
2889
2890 static struct access *
2891 get_access_for_expr (tree expr)
2892 {
2893   HOST_WIDE_INT offset, size, max_size;
2894   tree base;
2895   bool reverse;
2896
2897   /* FIXME: This should not be necessary but Ada produces V_C_Es with a type of
2898      a different size than the size of its argument and we need the latter
2899      one.  */
2900   if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
2901     expr = TREE_OPERAND (expr, 0);
2902
2903   base = get_ref_base_and_extent (expr, &offset, &size, &max_size, &reverse);
2904   if (max_size == -1 || !DECL_P (base))
2905     return NULL;
2906
2907   if (!bitmap_bit_p (candidate_bitmap, DECL_UID (base)))
2908     return NULL;
2909
2910   return get_var_base_offset_size_access (base, offset, max_size);
2911 }
2912
2913 /* Replace the expression EXPR with a scalar replacement if there is one and
2914    generate other statements to do type conversion or subtree copying if
2915    necessary.  GSI is used to place newly created statements, WRITE is true if
2916    the expression is being written to (it is on a LHS of a statement or output
2917    in an assembly statement).  */
2918
2919 static bool
2920 sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi, bool write)
2921 {
2922   location_t loc;
2923   struct access *access;
2924   tree type, bfr, orig_expr;
2925
2926   if (TREE_CODE (*expr) == BIT_FIELD_REF)
2927     {
2928       bfr = *expr;
2929       expr = &TREE_OPERAND (*expr, 0);
2930     }
2931   else
2932     bfr = NULL_TREE;
2933
2934   if (TREE_CODE (*expr) == REALPART_EXPR || TREE_CODE (*expr) == IMAGPART_EXPR)
2935     expr = &TREE_OPERAND (*expr, 0);
2936   access = get_access_for_expr (*expr);
2937   if (!access)
2938     return false;
2939   type = TREE_TYPE (*expr);
2940   orig_expr = *expr;
2941
2942   loc = gimple_location (gsi_stmt (*gsi));
2943   gimple_stmt_iterator alt_gsi = gsi_none ();
2944   if (write && stmt_ends_bb_p (gsi_stmt (*gsi)))
2945     {
2946       alt_gsi = gsi_start_edge (single_non_eh_succ (gsi_bb (*gsi)));
2947       gsi = &alt_gsi;
2948     }
2949
2950   if (access->grp_to_be_replaced)
2951     {
2952       tree repl = get_access_replacement (access);
2953       /* If we replace a non-register typed access simply use the original
2954          access expression to extract the scalar component afterwards.
2955          This happens if scalarizing a function return value or parameter
2956          like in gcc.c-torture/execute/20041124-1.c, 20050316-1.c and
2957          gcc.c-torture/compile/20011217-1.c.
2958
2959          We also want to use this when accessing a complex or vector which can
2960          be accessed as a different type too, potentially creating a need for
2961          type conversion (see PR42196) and when scalarized unions are involved
2962          in assembler statements (see PR42398).  */
2963       if (!useless_type_conversion_p (type, access->type))
2964         {
2965           tree ref;
2966
2967           ref = build_ref_for_model (loc, orig_expr, 0, access, gsi, false);
2968
2969           if (write)
2970             {
2971               gassign *stmt;
2972
2973               if (access->grp_partial_lhs)
2974                 ref = force_gimple_operand_gsi (gsi, ref, true, NULL_TREE,
2975                                                  false, GSI_NEW_STMT);
2976               stmt = gimple_build_assign (repl, ref);
2977               gimple_set_location (stmt, loc);
2978               gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2979             }
2980           else
2981             {
2982               gassign *stmt;
2983
2984               if (access->grp_partial_lhs)
2985                 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
2986                                                  true, GSI_SAME_STMT);
2987               stmt = gimple_build_assign (ref, repl);
2988               gimple_set_location (stmt, loc);
2989               gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2990             }
2991         }
2992       else
2993         *expr = repl;
2994       sra_stats.exprs++;
2995     }
2996   else if (write && access->grp_to_be_debug_replaced)
2997     {
2998       gdebug *ds = gimple_build_debug_bind (get_access_replacement (access),
2999                                             NULL_TREE,
3000                                             gsi_stmt (*gsi));
3001       gsi_insert_after (gsi, ds, GSI_NEW_STMT);
3002     }
3003
3004   if (access->first_child)
3005     {
3006       HOST_WIDE_INT start_offset, chunk_size;
3007       if (bfr
3008           && tree_fits_uhwi_p (TREE_OPERAND (bfr, 1))
3009           && tree_fits_uhwi_p (TREE_OPERAND (bfr, 2)))
3010         {
3011           chunk_size = tree_to_uhwi (TREE_OPERAND (bfr, 1));
3012           start_offset = access->offset
3013             + tree_to_uhwi (TREE_OPERAND (bfr, 2));
3014         }
3015       else
3016         start_offset = chunk_size = 0;
3017
3018       generate_subtree_copies (access->first_child, orig_expr, access->offset,
3019                                start_offset, chunk_size, gsi, write, write,
3020                                loc);
3021     }
3022   return true;
3023 }
3024
3025 /* Where scalar replacements of the RHS have been written to when a replacement
3026    of a LHS of an assigments cannot be direclty loaded from a replacement of
3027    the RHS. */
3028 enum unscalarized_data_handling { SRA_UDH_NONE,  /* Nothing done so far. */
3029                                   SRA_UDH_RIGHT, /* Data flushed to the RHS. */
3030                                   SRA_UDH_LEFT }; /* Data flushed to the LHS. */
3031
3032 struct subreplacement_assignment_data
3033 {
3034   /* Offset of the access representing the lhs of the assignment.  */
3035   HOST_WIDE_INT left_offset;
3036
3037   /* LHS and RHS of the original assignment.  */
3038   tree assignment_lhs, assignment_rhs;
3039
3040   /* Access representing the rhs of the whole assignment.  */
3041   struct access *top_racc;
3042
3043   /* Stmt iterator used for statement insertions after the original assignment.
3044    It points to the main GSI used to traverse a BB during function body
3045    modification.  */
3046   gimple_stmt_iterator *new_gsi;
3047
3048   /* Stmt iterator used for statement insertions before the original
3049    assignment.  Keeps on pointing to the original statement.  */
3050   gimple_stmt_iterator old_gsi;
3051
3052   /* Location of the assignment.   */
3053   location_t loc;
3054
3055   /* Keeps the information whether we have needed to refresh replacements of
3056    the LHS and from which side of the assignments this takes place.  */
3057   enum unscalarized_data_handling refreshed;
3058 };
3059
3060 /* Store all replacements in the access tree rooted in TOP_RACC either to their
3061    base aggregate if there are unscalarized data or directly to LHS of the
3062    statement that is pointed to by GSI otherwise.  */
3063
3064 static void
3065 handle_unscalarized_data_in_subtree (struct subreplacement_assignment_data *sad)
3066 {
3067   tree src;
3068   if (sad->top_racc->grp_unscalarized_data)
3069     {
3070       src = sad->assignment_rhs;
3071       sad->refreshed = SRA_UDH_RIGHT;
3072     }
3073   else
3074     {
3075       src = sad->assignment_lhs;
3076       sad->refreshed = SRA_UDH_LEFT;
3077     }
3078   generate_subtree_copies (sad->top_racc->first_child, src,
3079                            sad->top_racc->offset, 0, 0,
3080                            &sad->old_gsi, false, false, sad->loc);
3081 }
3082
3083 /* Try to generate statements to load all sub-replacements in an access subtree
3084    formed by children of LACC from scalar replacements in the SAD->top_racc
3085    subtree.  If that is not possible, refresh the SAD->top_racc base aggregate
3086    and load the accesses from it.  */
3087
3088 static void
3089 load_assign_lhs_subreplacements (struct access *lacc,
3090                                  struct subreplacement_assignment_data *sad)
3091 {
3092   for (lacc = lacc->first_child; lacc; lacc = lacc->next_sibling)
3093     {
3094       HOST_WIDE_INT offset;
3095       offset = lacc->offset - sad->left_offset + sad->top_racc->offset;
3096
3097       if (lacc->grp_to_be_replaced)
3098         {
3099           struct access *racc;
3100           gassign *stmt;
3101           tree rhs;
3102
3103           racc = find_access_in_subtree (sad->top_racc, offset, lacc->size);
3104           if (racc && racc->grp_to_be_replaced)
3105             {
3106               rhs = get_access_replacement (racc);
3107               if (!useless_type_conversion_p (lacc->type, racc->type))
3108                 rhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
3109                                        lacc->type, rhs);
3110
3111               if (racc->grp_partial_lhs && lacc->grp_partial_lhs)
3112                 rhs = force_gimple_operand_gsi (&sad->old_gsi, rhs, true,
3113                                                 NULL_TREE, true, GSI_SAME_STMT);
3114             }
3115           else
3116             {
3117               /* No suitable access on the right hand side, need to load from
3118                  the aggregate.  See if we have to update it first... */
3119               if (sad->refreshed == SRA_UDH_NONE)
3120                 handle_unscalarized_data_in_subtree (sad);
3121
3122               if (sad->refreshed == SRA_UDH_LEFT)
3123                 rhs = build_ref_for_model (sad->loc, sad->assignment_lhs,
3124                                            lacc->offset - sad->left_offset,
3125                                            lacc, sad->new_gsi, true);
3126               else
3127                 rhs = build_ref_for_model (sad->loc, sad->assignment_rhs,
3128                                            lacc->offset - sad->left_offset,
3129                                            lacc, sad->new_gsi, true);
3130               if (lacc->grp_partial_lhs)
3131                 rhs = force_gimple_operand_gsi (sad->new_gsi,
3132                                                 rhs, true, NULL_TREE,
3133                                                 false, GSI_NEW_STMT);
3134             }
3135
3136           stmt = gimple_build_assign (get_access_replacement (lacc), rhs);
3137           gsi_insert_after (sad->new_gsi, stmt, GSI_NEW_STMT);
3138           gimple_set_location (stmt, sad->loc);
3139           update_stmt (stmt);
3140           sra_stats.subreplacements++;
3141         }
3142       else
3143         {
3144           if (sad->refreshed == SRA_UDH_NONE
3145               && lacc->grp_read && !lacc->grp_covered)
3146             handle_unscalarized_data_in_subtree (sad);
3147
3148           if (lacc && lacc->grp_to_be_debug_replaced)
3149             {
3150               gdebug *ds;
3151               tree drhs;
3152               struct access *racc = find_access_in_subtree (sad->top_racc,
3153                                                             offset,
3154                                                             lacc->size);
3155
3156               if (racc && racc->grp_to_be_replaced)
3157                 {
3158                   if (racc->grp_write || constant_decl_p (racc->base))
3159                     drhs = get_access_replacement (racc);
3160                   else
3161                     drhs = NULL;
3162                 }
3163               else if (sad->refreshed == SRA_UDH_LEFT)
3164                 drhs = build_debug_ref_for_model (sad->loc, lacc->base,
3165                                                   lacc->offset, lacc);
3166               else if (sad->refreshed == SRA_UDH_RIGHT)
3167                 drhs = build_debug_ref_for_model (sad->loc, sad->top_racc->base,
3168                                                   offset, lacc);
3169               else
3170                 drhs = NULL_TREE;
3171               if (drhs
3172                   && !useless_type_conversion_p (lacc->type, TREE_TYPE (drhs)))
3173                 drhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
3174                                         lacc->type, drhs);
3175               ds = gimple_build_debug_bind (get_access_replacement (lacc),
3176                                             drhs, gsi_stmt (sad->old_gsi));
3177               gsi_insert_after (sad->new_gsi, ds, GSI_NEW_STMT);
3178             }
3179         }
3180
3181       if (lacc->first_child)
3182         load_assign_lhs_subreplacements (lacc, sad);
3183     }
3184 }
3185
3186 /* Result code for SRA assignment modification.  */
3187 enum assignment_mod_result { SRA_AM_NONE,       /* nothing done for the stmt */
3188                              SRA_AM_MODIFIED,  /* stmt changed but not
3189                                                   removed */
3190                              SRA_AM_REMOVED };  /* stmt eliminated */
3191
3192 /* Modify assignments with a CONSTRUCTOR on their RHS.  STMT contains a pointer
3193    to the assignment and GSI is the statement iterator pointing at it.  Returns
3194    the same values as sra_modify_assign.  */
3195
3196 static enum assignment_mod_result
3197 sra_modify_constructor_assign (gimple *stmt, gimple_stmt_iterator *gsi)
3198 {
3199   tree lhs = gimple_assign_lhs (stmt);
3200   struct access *acc = get_access_for_expr (lhs);
3201   if (!acc)
3202     return SRA_AM_NONE;
3203   location_t loc = gimple_location (stmt);
3204
3205   if (gimple_clobber_p (stmt))
3206     {
3207       /* Clobber the replacement variable.  */
3208       clobber_subtree (acc, gsi, !acc->grp_covered, loc);
3209       /* Remove clobbers of fully scalarized variables, they are dead.  */
3210       if (acc->grp_covered)
3211         {
3212           unlink_stmt_vdef (stmt);
3213           gsi_remove (gsi, true);
3214           release_defs (stmt);
3215           return SRA_AM_REMOVED;
3216         }
3217       else
3218         return SRA_AM_MODIFIED;
3219     }
3220
3221   if (vec_safe_length (CONSTRUCTOR_ELTS (gimple_assign_rhs1 (stmt))) > 0)
3222     {
3223       /* I have never seen this code path trigger but if it can happen the
3224          following should handle it gracefully.  */
3225       if (access_has_children_p (acc))
3226         generate_subtree_copies (acc->first_child, lhs, acc->offset, 0, 0, gsi,
3227                                  true, true, loc);
3228       return SRA_AM_MODIFIED;
3229     }
3230
3231   if (acc->grp_covered)
3232     {
3233       init_subtree_with_zero (acc, gsi, false, loc);
3234       unlink_stmt_vdef (stmt);
3235       gsi_remove (gsi, true);
3236       release_defs (stmt);
3237       return SRA_AM_REMOVED;
3238     }
3239   else
3240     {
3241       init_subtree_with_zero (acc, gsi, true, loc);
3242       return SRA_AM_MODIFIED;
3243     }
3244 }
3245
3246 /* Create and return a new suitable default definition SSA_NAME for RACC which
3247    is an access describing an uninitialized part of an aggregate that is being
3248    loaded.  */
3249
3250 static tree
3251 get_repl_default_def_ssa_name (struct access *racc)
3252 {
3253   gcc_checking_assert (!racc->grp_to_be_replaced
3254                        && !racc->grp_to_be_debug_replaced);
3255   if (!racc->replacement_decl)
3256     racc->replacement_decl = create_access_replacement (racc);
3257   return get_or_create_ssa_default_def (cfun, racc->replacement_decl);
3258 }
3259
3260 /* Return true if REF has an VIEW_CONVERT_EXPR or a COMPONENT_REF with a
3261    bit-field field declaration somewhere in it.  */
3262
3263 static inline bool
3264 contains_vce_or_bfcref_p (const_tree ref)
3265 {
3266   while (handled_component_p (ref))
3267     {
3268       if (TREE_CODE (ref) == VIEW_CONVERT_EXPR
3269           || (TREE_CODE (ref) == COMPONENT_REF
3270               && DECL_BIT_FIELD (TREE_OPERAND (ref, 1))))
3271         return true;
3272       ref = TREE_OPERAND (ref, 0);
3273     }
3274
3275   return false;
3276 }
3277
3278 /* Examine both sides of the assignment statement pointed to by STMT, replace
3279    them with a scalare replacement if there is one and generate copying of
3280    replacements if scalarized aggregates have been used in the assignment.  GSI
3281    is used to hold generated statements for type conversions and subtree
3282    copying.  */
3283
3284 static enum assignment_mod_result
3285 sra_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi)
3286 {
3287   struct access *lacc, *racc;
3288   tree lhs, rhs;
3289   bool modify_this_stmt = false;
3290   bool force_gimple_rhs = false;
3291   location_t loc;
3292   gimple_stmt_iterator orig_gsi = *gsi;
3293
3294   if (!gimple_assign_single_p (stmt))
3295     return SRA_AM_NONE;
3296   lhs = gimple_assign_lhs (stmt);
3297   rhs = gimple_assign_rhs1 (stmt);
3298
3299   if (TREE_CODE (rhs) == CONSTRUCTOR)
3300     return sra_modify_constructor_assign (stmt, gsi);
3301
3302   if (TREE_CODE (rhs) == REALPART_EXPR || TREE_CODE (lhs) == REALPART_EXPR
3303       || TREE_CODE (rhs) == IMAGPART_EXPR || TREE_CODE (lhs) == IMAGPART_EXPR
3304       || TREE_CODE (rhs) == BIT_FIELD_REF || TREE_CODE (lhs) == BIT_FIELD_REF)
3305     {
3306       modify_this_stmt = sra_modify_expr (gimple_assign_rhs1_ptr (stmt),
3307                                           gsi, false);
3308       modify_this_stmt |= sra_modify_expr (gimple_assign_lhs_ptr (stmt),
3309                                            gsi, true);
3310       return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
3311     }
3312
3313   lacc = get_access_for_expr (lhs);
3314   racc = get_access_for_expr (rhs);
3315   if (!lacc && !racc)
3316     return SRA_AM_NONE;
3317   /* Avoid modifying initializations of constant-pool replacements.  */
3318   if (racc && (racc->replacement_decl == lhs))
3319     return SRA_AM_NONE;
3320
3321   loc = gimple_location (stmt);
3322   if (lacc && lacc->grp_to_be_replaced)
3323     {
3324       lhs = get_access_replacement (lacc);
3325       gimple_assign_set_lhs (stmt, lhs);
3326       modify_this_stmt = true;
3327       if (lacc->grp_partial_lhs)
3328         force_gimple_rhs = true;
3329       sra_stats.exprs++;
3330     }
3331
3332   if (racc && racc->grp_to_be_replaced)
3333     {
3334       rhs = get_access_replacement (racc);
3335       modify_this_stmt = true;
3336       if (racc->grp_partial_lhs)
3337         force_gimple_rhs = true;
3338       sra_stats.exprs++;
3339     }
3340   else if (racc
3341            && !racc->grp_unscalarized_data
3342            && TREE_CODE (lhs) == SSA_NAME
3343            && !access_has_replacements_p (racc))
3344     {
3345       rhs = get_repl_default_def_ssa_name (racc);
3346       modify_this_stmt = true;
3347       sra_stats.exprs++;
3348     }
3349
3350   if (modify_this_stmt)
3351     {
3352       if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
3353         {
3354           /* If we can avoid creating a VIEW_CONVERT_EXPR do so.
3355              ???  This should move to fold_stmt which we simply should
3356              call after building a VIEW_CONVERT_EXPR here.  */
3357           if (AGGREGATE_TYPE_P (TREE_TYPE (lhs))
3358               && !contains_bitfld_component_ref_p (lhs))
3359             {
3360               lhs = build_ref_for_model (loc, lhs, 0, racc, gsi, false);
3361               gimple_assign_set_lhs (stmt, lhs);
3362             }
3363           else if (AGGREGATE_TYPE_P (TREE_TYPE (rhs))
3364                    && !contains_vce_or_bfcref_p (rhs))
3365             rhs = build_ref_for_model (loc, rhs, 0, lacc, gsi, false);
3366
3367           if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
3368             {
3369               rhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR, TREE_TYPE (lhs),
3370                                      rhs);
3371               if (is_gimple_reg_type (TREE_TYPE (lhs))
3372                   && TREE_CODE (lhs) != SSA_NAME)
3373                 force_gimple_rhs = true;
3374             }
3375         }
3376     }
3377
3378   if (lacc && lacc->grp_to_be_debug_replaced)
3379     {
3380       tree dlhs = get_access_replacement (lacc);
3381       tree drhs = unshare_expr (rhs);
3382       if (!useless_type_conversion_p (TREE_TYPE (dlhs), TREE_TYPE (drhs)))
3383         {
3384           if (AGGREGATE_TYPE_P (TREE_TYPE (drhs))
3385               && !contains_vce_or_bfcref_p (drhs))
3386             drhs = build_debug_ref_for_model (loc, drhs, 0, lacc);
3387           if (drhs
3388               && !useless_type_conversion_p (TREE_TYPE (dlhs),
3389                                              TREE_TYPE (drhs)))
3390             drhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR,
3391                                     TREE_TYPE (dlhs), drhs);
3392         }
3393       gdebug *ds = gimple_build_debug_bind (dlhs, drhs, stmt);
3394       gsi_insert_before (gsi, ds, GSI_SAME_STMT);
3395     }
3396
3397   /* From this point on, the function deals with assignments in between
3398      aggregates when at least one has scalar reductions of some of its
3399      components.  There are three possible scenarios: Both the LHS and RHS have
3400      to-be-scalarized components, 2) only the RHS has or 3) only the LHS has.
3401
3402      In the first case, we would like to load the LHS components from RHS
3403      components whenever possible.  If that is not possible, we would like to
3404      read it directly from the RHS (after updating it by storing in it its own
3405      components).  If there are some necessary unscalarized data in the LHS,
3406      those will be loaded by the original assignment too.  If neither of these
3407      cases happen, the original statement can be removed.  Most of this is done
3408      by load_assign_lhs_subreplacements.
3409
3410      In the second case, we would like to store all RHS scalarized components
3411      directly into LHS and if they cover the aggregate completely, remove the
3412      statement too.  In the third case, we want the LHS components to be loaded
3413      directly from the RHS (DSE will remove the original statement if it
3414      becomes redundant).
3415
3416      This is a bit complex but manageable when types match and when unions do
3417      not cause confusion in a way that we cannot really load a component of LHS
3418      from the RHS or vice versa (the access representing this level can have
3419      subaccesses that are accessible only through a different union field at a
3420      higher level - different from the one used in the examined expression).
3421      Unions are fun.
3422
3423      Therefore, I specially handle a fourth case, happening when there is a
3424      specific type cast or it is impossible to locate a scalarized subaccess on
3425      the other side of the expression.  If that happens, I simply "refresh" the
3426      RHS by storing in it is scalarized components leave the original statement
3427      there to do the copying and then load the scalar replacements of the LHS.
3428      This is what the first branch does.  */
3429
3430   if (modify_this_stmt
3431       || gimple_has_volatile_ops (stmt)
3432       || contains_vce_or_bfcref_p (rhs)
3433       || contains_vce_or_bfcref_p (lhs)
3434       || stmt_ends_bb_p (stmt))
3435     {
3436       /* No need to copy into a constant-pool, it comes pre-initialized.  */
3437       if (access_has_children_p (racc) && !constant_decl_p (racc->base))
3438         generate_subtree_copies (racc->first_child, rhs, racc->offset, 0, 0,
3439                                  gsi, false, false, loc);
3440       if (access_has_children_p (lacc))
3441         {
3442           gimple_stmt_iterator alt_gsi = gsi_none ();
3443           if (stmt_ends_bb_p (stmt))
3444             {
3445               alt_gsi = gsi_start_edge (single_non_eh_succ (gsi_bb (*gsi)));
3446               gsi = &alt_gsi;
3447             }
3448           generate_subtree_copies (lacc->first_child, lhs, lacc->offset, 0, 0,
3449                                    gsi, true, true, loc);
3450         }
3451       sra_stats.separate_lhs_rhs_handling++;
3452
3453       /* This gimplification must be done after generate_subtree_copies,
3454          lest we insert the subtree copies in the middle of the gimplified
3455          sequence.  */
3456       if (force_gimple_rhs)
3457         rhs = force_gimple_operand_gsi (&orig_gsi, rhs, true, NULL_TREE,
3458                                         true, GSI_SAME_STMT);
3459       if (gimple_assign_rhs1 (stmt) != rhs)
3460         {
3461           modify_this_stmt = true;
3462           gimple_assign_set_rhs_from_tree (&orig_gsi, rhs);
3463           gcc_assert (stmt == gsi_stmt (orig_gsi));
3464         }
3465
3466       return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
3467     }
3468   else
3469     {
3470       if (access_has_children_p (lacc)
3471           && access_has_children_p (racc)
3472           /* When an access represents an unscalarizable region, it usually
3473              represents accesses with variable offset and thus must not be used
3474              to generate new memory accesses.  */
3475           && !lacc->grp_unscalarizable_region
3476           && !racc->grp_unscalarizable_region)
3477         {
3478           struct subreplacement_assignment_data sad;
3479
3480           sad.left_offset = lacc->offset;
3481           sad.assignment_lhs = lhs;
3482           sad.assignment_rhs = rhs;
3483           sad.top_racc = racc;
3484           sad.old_gsi = *gsi;
3485           sad.new_gsi = gsi;
3486           sad.loc = gimple_location (stmt);
3487           sad.refreshed = SRA_UDH_NONE;
3488
3489           if (lacc->grp_read && !lacc->grp_covered)
3490             handle_unscalarized_data_in_subtree (&sad);
3491
3492           load_assign_lhs_subreplacements (lacc, &sad);
3493           if (sad.refreshed != SRA_UDH_RIGHT)
3494             {
3495               gsi_next (gsi);
3496               unlink_stmt_vdef (stmt);
3497               gsi_remove (&sad.old_gsi, true);
3498               release_defs (stmt);
3499               sra_stats.deleted++;
3500               return SRA_AM_REMOVED;
3501             }
3502         }
3503       else
3504         {
3505           if (access_has_children_p (racc)
3506               && !racc->grp_unscalarized_data)
3507             {
3508               if (dump_file)
3509                 {
3510                   fprintf (dump_file, "Removing load: ");
3511                   print_gimple_stmt (dump_file, stmt, 0, 0);
3512                 }
3513               generate_subtree_copies (racc->first_child, lhs,
3514                                        racc->offset, 0, 0, gsi,
3515                                        false, false, loc);
3516               gcc_assert (stmt == gsi_stmt (*gsi));
3517               unlink_stmt_vdef (stmt);
3518               gsi_remove (gsi, true);
3519               release_defs (stmt);
3520               sra_stats.deleted++;
3521               return SRA_AM_REMOVED;
3522             }
3523           /* Restore the aggregate RHS from its components so the
3524              prevailing aggregate copy does the right thing.  */
3525           if (access_has_children_p (racc))
3526             generate_subtree_copies (racc->first_child, rhs, racc->offset, 0, 0,
3527                                      gsi, false, false, loc);
3528           /* Re-load the components of the aggregate copy destination.
3529              But use the RHS aggregate to load from to expose more
3530              optimization opportunities.  */
3531           if (access_has_children_p (lacc))
3532             generate_subtree_copies (lacc->first_child, rhs, lacc->offset,
3533                                      0, 0, gsi, true, true, loc);
3534         }
3535
3536       return SRA_AM_NONE;
3537     }
3538 }
3539
3540 /* Set any scalar replacements of values in the constant pool to the initial
3541    value of the constant.  (Constant-pool decls like *.LC0 have effectively
3542    been initialized before the program starts, we must do the same for their
3543    replacements.)  Thus, we output statements like 'SR.1 = *.LC0[0];' into
3544    the function's entry block.  */
3545
3546 static void
3547 initialize_constant_pool_replacements (void)
3548 {
3549   gimple_seq seq = NULL;
3550   gimple_stmt_iterator gsi = gsi_start (seq);
3551   bitmap_iterator bi;
3552   unsigned i;
3553
3554   EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
3555     if (bitmap_bit_p (should_scalarize_away_bitmap, i)
3556         && !bitmap_bit_p (cannot_scalarize_away_bitmap, i))
3557       {
3558         tree var = candidate (i);
3559         if (!constant_decl_p (var))
3560           continue;
3561         vec<access_p> *access_vec = get_base_access_vector (var);
3562         if (!access_vec)
3563           continue;
3564         for (unsigned i = 0; i < access_vec->length (); i++)
3565           {
3566             struct access *access = (*access_vec)[i];
3567             if (!access->replacement_decl)
3568               continue;
3569             gassign *stmt = gimple_build_assign (
3570               get_access_replacement (access), unshare_expr (access->expr));
3571             if (dump_file && (dump_flags & TDF_DETAILS))
3572               {
3573                 fprintf (dump_file, "Generating constant initializer: ");
3574                 print_gimple_stmt (dump_file, stmt, 0, 1);
3575                 fprintf (dump_file, "\n");
3576               }
3577             gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
3578             update_stmt (stmt);
3579           }
3580       }
3581
3582   seq = gsi_seq (gsi);
3583   if (seq)
3584     gsi_insert_seq_on_edge_immediate (
3585       single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)), seq);
3586 }
3587
3588 /* Traverse the function body and all modifications as decided in
3589    analyze_all_variable_accesses.  Return true iff the CFG has been
3590    changed.  */
3591
3592 static bool
3593 sra_modify_function_body (void)
3594 {
3595   bool cfg_changed = false;
3596   basic_block bb;
3597
3598   initialize_constant_pool_replacements ();
3599
3600   FOR_EACH_BB_FN (bb, cfun)
3601     {
3602       gimple_stmt_iterator gsi = gsi_start_bb (bb);
3603       while (!gsi_end_p (gsi))
3604         {
3605           gimple *stmt = gsi_stmt (gsi);
3606           enum assignment_mod_result assign_result;
3607           bool modified = false, deleted = false;
3608           tree *t;
3609           unsigned i;
3610
3611           switch (gimple_code (stmt))
3612             {
3613             case GIMPLE_RETURN:
3614               t = gimple_return_retval_ptr (as_a <greturn *> (stmt));
3615               if (*t != NULL_TREE)
3616                 modified |= sra_modify_expr (t, &gsi, false);
3617               break;
3618
3619             case GIMPLE_ASSIGN:
3620               assign_result = sra_modify_assign (stmt, &gsi);
3621               modified |= assign_result == SRA_AM_MODIFIED;
3622               deleted = assign_result == SRA_AM_REMOVED;
3623               break;
3624
3625             case GIMPLE_CALL:
3626               /* Operands must be processed before the lhs.  */
3627               for (i = 0; i < gimple_call_num_args (stmt); i++)
3628                 {
3629                   t = gimple_call_arg_ptr (stmt, i);
3630                   modified |= sra_modify_expr (t, &gsi, false);
3631                 }
3632
3633               if (gimple_call_lhs (stmt))
3634                 {
3635                   t = gimple_call_lhs_ptr (stmt);
3636                   modified |= sra_modify_expr (t, &gsi, true);
3637                 }
3638               break;
3639
3640             case GIMPLE_ASM:
3641               {
3642                 gasm *asm_stmt = as_a <gasm *> (stmt);
3643                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
3644                   {
3645                     t = &TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
3646                     modified |= sra_modify_expr (t, &gsi, false);
3647                   }
3648                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
3649                   {
3650                     t = &TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
3651                     modified |= sra_modify_expr (t, &gsi, true);
3652                   }
3653               }
3654               break;
3655
3656             default:
3657               break;
3658             }
3659
3660           if (modified)
3661             {
3662               update_stmt (stmt);
3663               if (maybe_clean_eh_stmt (stmt)
3664                   && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
3665                 cfg_changed = true;
3666             }
3667           if (!deleted)
3668             gsi_next (&gsi);
3669         }
3670     }
3671
3672   gsi_commit_edge_inserts ();
3673   return cfg_changed;
3674 }
3675
3676 /* Generate statements initializing scalar replacements of parts of function
3677    parameters.  */
3678
3679 static void
3680 initialize_parameter_reductions (void)
3681 {
3682   gimple_stmt_iterator gsi;
3683   gimple_seq seq = NULL;
3684   tree parm;
3685
3686   gsi = gsi_start (seq);
3687   for (parm = DECL_ARGUMENTS (current_function_decl);
3688        parm;
3689        parm = DECL_CHAIN (parm))
3690     {
3691       vec<access_p> *access_vec;
3692       struct access *access;
3693
3694       if (!bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
3695         continue;
3696       access_vec = get_base_access_vector (parm);
3697       if (!access_vec)
3698         continue;
3699
3700       for (access = (*access_vec)[0];
3701            access;
3702            access = access->next_grp)
3703         generate_subtree_copies (access, parm, 0, 0, 0, &gsi, true, true,
3704                                  EXPR_LOCATION (parm));
3705     }
3706
3707   seq = gsi_seq (gsi);
3708   if (seq)
3709     gsi_insert_seq_on_edge_immediate (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)), seq);
3710 }
3711
3712 /* The "main" function of intraprocedural SRA passes.  Runs the analysis and if
3713    it reveals there are components of some aggregates to be scalarized, it runs
3714    the required transformations.  */
3715 static unsigned int
3716 perform_intra_sra (void)
3717 {
3718   int ret = 0;
3719   sra_initialize ();
3720
3721   if (!find_var_candidates ())
3722     goto out;
3723
3724   if (!scan_function ())
3725     goto out;
3726
3727   if (!analyze_all_variable_accesses ())
3728     goto out;
3729
3730   if (sra_modify_function_body ())
3731     ret = TODO_update_ssa | TODO_cleanup_cfg;
3732   else
3733     ret = TODO_update_ssa;
3734   initialize_parameter_reductions ();
3735
3736   statistics_counter_event (cfun, "Scalar replacements created",
3737                             sra_stats.replacements);
3738   statistics_counter_event (cfun, "Modified expressions", sra_stats.exprs);
3739   statistics_counter_event (cfun, "Subtree copy stmts",
3740                             sra_stats.subtree_copies);
3741   statistics_counter_event (cfun, "Subreplacement stmts",
3742                             sra_stats.subreplacements);
3743   statistics_counter_event (cfun, "Deleted stmts", sra_stats.deleted);
3744   statistics_counter_event (cfun, "Separate LHS and RHS handling",
3745                             sra_stats.separate_lhs_rhs_handling);
3746
3747  out:
3748   sra_deinitialize ();
3749   return ret;
3750 }
3751
3752 /* Perform early intraprocedural SRA.  */
3753 static unsigned int
3754 early_intra_sra (void)
3755 {
3756   sra_mode = SRA_MODE_EARLY_INTRA;
3757   return perform_intra_sra ();
3758 }
3759
3760 /* Perform "late" intraprocedural SRA.  */
3761 static unsigned int
3762 late_intra_sra (void)
3763 {
3764   sra_mode = SRA_MODE_INTRA;
3765   return perform_intra_sra ();
3766 }
3767
3768
3769 static bool
3770 gate_intra_sra (void)
3771 {
3772   return flag_tree_sra != 0 && dbg_cnt (tree_sra);
3773 }
3774
3775
3776 namespace {
3777
3778 const pass_data pass_data_sra_early =
3779 {
3780   GIMPLE_PASS, /* type */
3781   "esra", /* name */
3782   OPTGROUP_NONE, /* optinfo_flags */
3783   TV_TREE_SRA, /* tv_id */
3784   ( PROP_cfg | PROP_ssa ), /* properties_required */
3785   0, /* properties_provided */
3786   0, /* properties_destroyed */
3787   0, /* todo_flags_start */
3788   TODO_update_ssa, /* todo_flags_finish */
3789 };
3790
3791 class pass_sra_early : public gimple_opt_pass
3792 {
3793 public:
3794   pass_sra_early (gcc::context *ctxt)
3795     : gimple_opt_pass (pass_data_sra_early, ctxt)
3796   {}
3797
3798   /* opt_pass methods: */
3799   virtual bool gate (function *) { return gate_intra_sra (); }
3800   virtual unsigned int execute (function *) { return early_intra_sra (); }
3801
3802 }; // class pass_sra_early
3803
3804 } // anon namespace
3805
3806 gimple_opt_pass *
3807 make_pass_sra_early (gcc::context *ctxt)
3808 {
3809   return new pass_sra_early (ctxt);
3810 }
3811
3812 namespace {
3813
3814 const pass_data pass_data_sra =
3815 {
3816   GIMPLE_PASS, /* type */
3817   "sra", /* name */
3818   OPTGROUP_NONE, /* optinfo_flags */
3819   TV_TREE_SRA, /* tv_id */
3820   ( PROP_cfg | PROP_ssa ), /* properties_required */
3821   0, /* properties_provided */
3822   0, /* properties_destroyed */
3823   TODO_update_address_taken, /* todo_flags_start */
3824   TODO_update_ssa, /* todo_flags_finish */
3825 };
3826
3827 class pass_sra : public gimple_opt_pass
3828 {
3829 public:
3830   pass_sra (gcc::context *ctxt)
3831     : gimple_opt_pass (pass_data_sra, ctxt)
3832   {}
3833
3834   /* opt_pass methods: */
3835   virtual bool gate (function *) { return gate_intra_sra (); }
3836   virtual unsigned int execute (function *) { return late_intra_sra (); }
3837
3838 }; // class pass_sra
3839
3840 } // anon namespace
3841
3842 gimple_opt_pass *
3843 make_pass_sra (gcc::context *ctxt)
3844 {
3845   return new pass_sra (ctxt);
3846 }
3847
3848
3849 /* Return true iff PARM (which must be a parm_decl) is an unused scalar
3850    parameter.  */
3851
3852 static bool
3853 is_unused_scalar_param (tree parm)
3854 {
3855   tree name;
3856   return (is_gimple_reg (parm)
3857           && (!(name = ssa_default_def (cfun, parm))
3858               || has_zero_uses (name)));
3859 }
3860
3861 /* Scan immediate uses of a default definition SSA name of a parameter PARM and
3862    examine whether there are any direct or otherwise infeasible ones.  If so,
3863    return true, otherwise return false.  PARM must be a gimple register with a
3864    non-NULL default definition.  */
3865
3866 static bool
3867 ptr_parm_has_direct_uses (tree parm)
3868 {
3869   imm_use_iterator ui;
3870   gimple *stmt;
3871   tree name = ssa_default_def (cfun, parm);
3872   bool ret = false;
3873
3874   FOR_EACH_IMM_USE_STMT (stmt, ui, name)
3875     {
3876       int uses_ok = 0;
3877       use_operand_p use_p;
3878
3879       if (is_gimple_debug (stmt))
3880         continue;
3881
3882       /* Valid uses include dereferences on the lhs and the rhs.  */
3883       if (gimple_has_lhs (stmt))
3884         {
3885           tree lhs = gimple_get_lhs (stmt);
3886           while (handled_component_p (lhs))
3887             lhs = TREE_OPERAND (lhs, 0);
3888           if (TREE_CODE (lhs) == MEM_REF
3889               && TREE_OPERAND (lhs, 0) == name
3890               && integer_zerop (TREE_OPERAND (lhs, 1))
3891               && types_compatible_p (TREE_TYPE (lhs),
3892                                      TREE_TYPE (TREE_TYPE (name)))
3893               && !TREE_THIS_VOLATILE (lhs))
3894             uses_ok++;
3895         }
3896       if (gimple_assign_single_p (stmt))
3897         {
3898           tree rhs = gimple_assign_rhs1 (stmt);
3899           while (handled_component_p (rhs))
3900             rhs = TREE_OPERAND (rhs, 0);
3901           if (TREE_CODE (rhs) == MEM_REF
3902               && TREE_OPERAND (rhs, 0) == name
3903               && integer_zerop (TREE_OPERAND (rhs, 1))
3904               && types_compatible_p (TREE_TYPE (rhs),
3905                                      TREE_TYPE (TREE_TYPE (name)))
3906               && !TREE_THIS_VOLATILE (rhs))
3907             uses_ok++;
3908         }
3909       else if (is_gimple_call (stmt))
3910         {
3911           unsigned i;
3912           for (i = 0; i < gimple_call_num_args (stmt); ++i)
3913             {
3914               tree arg = gimple_call_arg (stmt, i);
3915               while (handled_component_p (arg))
3916                 arg = TREE_OPERAND (arg, 0);
3917               if (TREE_CODE (arg) == MEM_REF
3918                   && TREE_OPERAND (arg, 0) == name
3919                   && integer_zerop (TREE_OPERAND (arg, 1))
3920                   && types_compatible_p (TREE_TYPE (arg),
3921                                          TREE_TYPE (TREE_TYPE (name)))
3922                   && !TREE_THIS_VOLATILE (arg))
3923                 uses_ok++;
3924             }
3925         }
3926
3927       /* If the number of valid uses does not match the number of
3928          uses in this stmt there is an unhandled use.  */
3929       FOR_EACH_IMM_USE_ON_STMT (use_p, ui)
3930         --uses_ok;
3931
3932       if (uses_ok != 0)
3933         ret = true;
3934
3935       if (ret)
3936         BREAK_FROM_IMM_USE_STMT (ui);
3937     }
3938
3939   return ret;
3940 }
3941
3942 /* Identify candidates for reduction for IPA-SRA based on their type and mark
3943    them in candidate_bitmap.  Note that these do not necessarily include
3944    parameter which are unused and thus can be removed.  Return true iff any
3945    such candidate has been found.  */
3946
3947 static bool
3948 find_param_candidates (void)
3949 {
3950   tree parm;
3951   int count = 0;
3952   bool ret = false;
3953   const char *msg;
3954
3955   for (parm = DECL_ARGUMENTS (current_function_decl);
3956        parm;
3957        parm = DECL_CHAIN (parm))
3958     {
3959       tree type = TREE_TYPE (parm);
3960       tree_node **slot;
3961
3962       count++;
3963
3964       if (TREE_THIS_VOLATILE (parm)
3965           || TREE_ADDRESSABLE (parm)
3966           || (!is_gimple_reg_type (type) && is_va_list_type (type)))
3967         continue;
3968
3969       if (is_unused_scalar_param (parm))
3970         {
3971           ret = true;
3972           continue;
3973         }
3974
3975       if (POINTER_TYPE_P (type))
3976         {
3977           type = TREE_TYPE (type);
3978
3979           if (TREE_CODE (type) == FUNCTION_TYPE
3980               || TYPE_VOLATILE (type)
3981               || (TREE_CODE (type) == ARRAY_TYPE
3982                   && TYPE_NONALIASED_COMPONENT (type))
3983               || !is_gimple_reg (parm)
3984               || is_va_list_type (type)
3985               || ptr_parm_has_direct_uses (parm))
3986             continue;
3987         }
3988       else if (!AGGREGATE_TYPE_P (type))
3989         continue;
3990
3991       if (!COMPLETE_TYPE_P (type)
3992           || !tree_fits_uhwi_p (TYPE_SIZE (type))
3993           || tree_to_uhwi (TYPE_SIZE (type)) == 0
3994           || (AGGREGATE_TYPE_P (type)
3995               && type_internals_preclude_sra_p (type, &msg)))
3996         continue;
3997
3998       bitmap_set_bit (candidate_bitmap, DECL_UID (parm));
3999       slot = candidates->find_slot_with_hash (parm, DECL_UID (parm), INSERT);
4000       *slot = parm;
4001
4002       ret = true;
4003       if (dump_file && (dump_flags & TDF_DETAILS))
4004         {
4005           fprintf (dump_file, "Candidate (%d): ", DECL_UID (parm));
4006           print_generic_expr (dump_file, parm, 0);
4007           fprintf (dump_file, "\n");
4008         }
4009     }
4010
4011   func_param_count = count;
4012   return ret;
4013 }
4014
4015 /* Callback of walk_aliased_vdefs, marks the access passed as DATA as
4016    maybe_modified. */
4017
4018 static bool
4019 mark_maybe_modified (ao_ref *ao ATTRIBUTE_UNUSED, tree vdef ATTRIBUTE_UNUSED,
4020                      void *data)
4021 {
4022   struct access *repr = (struct access *) data;
4023
4024   repr->grp_maybe_modified = 1;
4025   return true;
4026 }
4027
4028 /* Analyze what representatives (in linked lists accessible from
4029    REPRESENTATIVES) can be modified by side effects of statements in the
4030    current function.  */
4031
4032 static void
4033 analyze_modified_params (vec<access_p> representatives)
4034 {
4035   int i;
4036
4037   for (i = 0; i < func_param_count; i++)
4038     {
4039       struct access *repr;
4040
4041       for (repr = representatives[i];
4042            repr;
4043            repr = repr->next_grp)
4044         {
4045           struct access *access;
4046           bitmap visited;
4047           ao_ref ar;
4048
4049           if (no_accesses_p (repr))
4050             continue;
4051           if (!POINTER_TYPE_P (TREE_TYPE (repr->base))
4052               || repr->grp_maybe_modified)
4053             continue;
4054
4055           ao_ref_init (&ar, repr->expr);
4056           visited = BITMAP_ALLOC (NULL);
4057           for (access = repr; access; access = access->next_sibling)
4058             {
4059               /* All accesses are read ones, otherwise grp_maybe_modified would
4060                  be trivially set.  */
4061               walk_aliased_vdefs (&ar, gimple_vuse (access->stmt),
4062                                   mark_maybe_modified, repr, &visited);
4063               if (repr->grp_maybe_modified)
4064                 break;
4065             }
4066           BITMAP_FREE (visited);
4067         }
4068     }
4069 }
4070
4071 /* Propagate distances in bb_dereferences in the opposite direction than the
4072    control flow edges, in each step storing the maximum of the current value
4073    and the minimum of all successors.  These steps are repeated until the table
4074    stabilizes.  Note that BBs which might terminate the functions (according to
4075    final_bbs bitmap) never updated in this way.  */
4076
4077 static void
4078 propagate_dereference_distances (void)
4079 {
4080   basic_block bb;
4081
4082   auto_vec<basic_block> queue (last_basic_block_for_fn (cfun));
4083   queue.quick_push (ENTRY_BLOCK_PTR_FOR_FN (cfun));
4084   FOR_EACH_BB_FN (bb, cfun)
4085     {
4086       queue.quick_push (bb);
4087       bb->aux = bb;
4088     }
4089
4090   while (!queue.is_empty ())
4091     {
4092       edge_iterator ei;
4093       edge e;
4094       bool change = false;
4095       int i;
4096
4097       bb = queue.pop ();
4098       bb->aux = NULL;
4099
4100       if (bitmap_bit_p (final_bbs, bb->index))
4101         continue;
4102
4103       for (i = 0; i < func_param_count; i++)
4104         {
4105           int idx = bb->index * func_param_count + i;
4106           bool first = true;
4107           HOST_WIDE_INT inh = 0;
4108
4109           FOR_EACH_EDGE (e, ei, bb->succs)
4110           {
4111             int succ_idx = e->dest->index * func_param_count + i;
4112
4113             if (e->src == EXIT_BLOCK_PTR_FOR_FN (cfun))
4114               continue;
4115
4116             if (first)
4117               {
4118                 first = false;
4119                 inh = bb_dereferences [succ_idx];
4120               }
4121             else if (bb_dereferences [succ_idx] < inh)
4122               inh = bb_dereferences [succ_idx];
4123           }
4124
4125           if (!first && bb_dereferences[idx] < inh)
4126             {
4127               bb_dereferences[idx] = inh;
4128               change = true;
4129             }
4130         }
4131
4132       if (change && !bitmap_bit_p (final_bbs, bb->index))
4133         FOR_EACH_EDGE (e, ei, bb->preds)
4134           {
4135             if (e->src->aux)
4136               continue;
4137
4138             e->src->aux = e->src;
4139             queue.quick_push (e->src);
4140           }
4141     }
4142 }
4143
4144 /* Dump a dereferences TABLE with heading STR to file F.  */
4145
4146 static void
4147 dump_dereferences_table (FILE *f, const char *str, HOST_WIDE_INT *table)
4148 {
4149   basic_block bb;
4150
4151   fprintf (dump_file, "%s", str);
4152   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun),
4153                   EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb)
4154     {
4155       fprintf (f, "%4i  %i   ", bb->index, bitmap_bit_p (final_bbs, bb->index));
4156       if (bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
4157         {
4158           int i;
4159           for (i = 0; i < func_param_count; i++)
4160             {
4161               int idx = bb->index * func_param_count + i;
4162               fprintf (f, " %4" HOST_WIDE_INT_PRINT "d", table[idx]);
4163             }
4164         }
4165       fprintf (f, "\n");
4166     }
4167   fprintf (dump_file, "\n");
4168 }
4169
4170 /* Determine what (parts of) parameters passed by reference that are not
4171    assigned to are not certainly dereferenced in this function and thus the
4172    dereferencing cannot be safely moved to the caller without potentially
4173    introducing a segfault.  Mark such REPRESENTATIVES as
4174    grp_not_necessarilly_dereferenced.
4175
4176    The dereferenced maximum "distance," i.e. the offset + size of the accessed
4177    part is calculated rather than simple booleans are calculated for each
4178    pointer parameter to handle cases when only a fraction of the whole
4179    aggregate is allocated (see testsuite/gcc.c-torture/execute/ipa-sra-2.c for
4180    an example).
4181
4182    The maximum dereference distances for each pointer parameter and BB are
4183    already stored in bb_dereference.  This routine simply propagates these
4184    values upwards by propagate_dereference_distances and then compares the
4185    distances of individual parameters in the ENTRY BB to the equivalent
4186    distances of each representative of a (fraction of a) parameter.  */
4187
4188 static void
4189 analyze_caller_dereference_legality (vec<access_p> representatives)
4190 {
4191   int i;
4192
4193   if (dump_file && (dump_flags & TDF_DETAILS))
4194     dump_dereferences_table (dump_file,
4195                              "Dereference table before propagation:\n",
4196                              bb_dereferences);
4197
4198   propagate_dereference_distances ();
4199
4200   if (dump_file && (dump_flags & TDF_DETAILS))
4201     dump_dereferences_table (dump_file,
4202                              "Dereference table after propagation:\n",
4203                              bb_dereferences);
4204
4205   for (i = 0; i < func_param_count; i++)
4206     {
4207       struct access *repr = representatives[i];
4208       int idx = ENTRY_BLOCK_PTR_FOR_FN (cfun)->index * func_param_count + i;
4209
4210       if (!repr || no_accesses_p (repr))
4211         continue;
4212
4213       do
4214         {
4215           if ((repr->offset + repr->size) > bb_dereferences[idx])
4216             repr->grp_not_necessarilly_dereferenced = 1;
4217           repr = repr->next_grp;
4218         }
4219       while (repr);
4220     }
4221 }
4222
4223 /* Return the representative access for the parameter declaration PARM if it is
4224    a scalar passed by reference which is not written to and the pointer value
4225    is not used directly.  Thus, if it is legal to dereference it in the caller
4226    and we can rule out modifications through aliases, such parameter should be
4227    turned into one passed by value.  Return NULL otherwise.  */
4228
4229 static struct access *
4230 unmodified_by_ref_scalar_representative (tree parm)
4231 {
4232   int i, access_count;
4233   struct access *repr;
4234   vec<access_p> *access_vec;
4235
4236   access_vec = get_base_access_vector (parm);
4237   gcc_assert (access_vec);
4238   repr = (*access_vec)[0];
4239   if (repr->write)
4240     return NULL;
4241   repr->group_representative = repr;
4242
4243   access_count = access_vec->length ();
4244   for (i = 1; i < access_count; i++)
4245     {
4246       struct access *access = (*access_vec)[i];
4247       if (access->write)
4248         return NULL;
4249       access->group_representative = repr;
4250       access->next_sibling = repr->next_sibling;
4251       repr->next_sibling = access;
4252     }
4253
4254   repr->grp_read = 1;
4255   repr->grp_scalar_ptr = 1;
4256   return repr;
4257 }
4258
4259 /* Return true iff this ACCESS precludes IPA-SRA of the parameter it is
4260    associated with.  REQ_ALIGN is the minimum required alignment.  */
4261
4262 static bool
4263 access_precludes_ipa_sra_p (struct access *access, unsigned int req_align)
4264 {
4265   unsigned int exp_align;
4266   /* Avoid issues such as the second simple testcase in PR 42025.  The problem
4267      is incompatible assign in a call statement (and possibly even in asm
4268      statements).  This can be relaxed by using a new temporary but only for
4269      non-TREE_ADDRESSABLE types and is probably not worth the complexity. (In
4270      intraprocedural SRA we deal with this by keeping the old aggregate around,
4271      something we cannot do in IPA-SRA.)  */
4272   if (access->write
4273       && (is_gimple_call (access->stmt)
4274           || gimple_code (access->stmt) == GIMPLE_ASM))
4275     return true;
4276
4277   exp_align = get_object_alignment (access->expr);
4278   if (exp_align < req_align)
4279     return true;
4280
4281   return false;
4282 }
4283
4284
4285 /* Sort collected accesses for parameter PARM, identify representatives for
4286    each accessed region and link them together.  Return NULL if there are
4287    different but overlapping accesses, return the special ptr value meaning
4288    there are no accesses for this parameter if that is the case and return the
4289    first representative otherwise.  Set *RO_GRP if there is a group of accesses
4290    with only read (i.e. no write) accesses.  */
4291
4292 static struct access *
4293 splice_param_accesses (tree parm, bool *ro_grp)
4294 {
4295   int i, j, access_count, group_count;
4296   int agg_size, total_size = 0;
4297   struct access *access, *res, **prev_acc_ptr = &res;
4298   vec<access_p> *access_vec;
4299
4300   access_vec = get_base_access_vector (parm);
4301   if (!access_vec)
4302     return &no_accesses_representant;
4303   access_count = access_vec->length ();
4304
4305   access_vec->qsort (compare_access_positions);
4306
4307   i = 0;
4308   total_size = 0;
4309   group_count = 0;
4310   while (i < access_count)
4311     {
4312       bool modification;
4313       tree a1_alias_type;
4314       access = (*access_vec)[i];
4315       modification = access->write;
4316       if (access_precludes_ipa_sra_p (access, TYPE_ALIGN (access->type)))
4317         return NULL;
4318       a1_alias_type = reference_alias_ptr_type (access->expr);
4319
4320       /* Access is about to become group representative unless we find some
4321          nasty overlap which would preclude us from breaking this parameter
4322          apart. */
4323
4324       j = i + 1;
4325       while (j < access_count)
4326         {
4327           struct access *ac2 = (*access_vec)[j];
4328           if (ac2->offset != access->offset)
4329             {
4330               /* All or nothing law for parameters. */
4331               if (access->offset + access->size > ac2->offset)
4332                 return NULL;
4333               else
4334                 break;
4335             }
4336           else if (ac2->size != access->size)
4337             return NULL;
4338
4339           if (access_precludes_ipa_sra_p (ac2, TYPE_ALIGN (access->type))
4340               || (ac2->type != access->type
4341                   && (TREE_ADDRESSABLE (ac2->type)
4342                       || TREE_ADDRESSABLE (access->type)))
4343               || (reference_alias_ptr_type (ac2->expr) != a1_alias_type))
4344             return NULL;
4345
4346           modification |= ac2->write;
4347           ac2->group_representative = access;
4348           ac2->next_sibling = access->next_sibling;
4349           access->next_sibling = ac2;
4350           j++;
4351         }
4352
4353       group_count++;
4354       access->grp_maybe_modified = modification;
4355       if (!modification)
4356         *ro_grp = true;
4357       *prev_acc_ptr = access;
4358       prev_acc_ptr = &access->next_grp;
4359       total_size += access->size;
4360       i = j;
4361     }
4362
4363   if (POINTER_TYPE_P (TREE_TYPE (parm)))
4364     agg_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (TREE_TYPE (parm))));
4365   else
4366     agg_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (parm)));
4367   if (total_size >= agg_size)
4368     return NULL;
4369
4370   gcc_assert (group_count > 0);
4371   return res;
4372 }
4373
4374 /* Decide whether parameters with representative accesses given by REPR should
4375    be reduced into components.  */
4376
4377 static int
4378 decide_one_param_reduction (struct access *repr)
4379 {
4380   int total_size, cur_parm_size, agg_size, new_param_count, parm_size_limit;
4381   bool by_ref;
4382   tree parm;
4383
4384   parm = repr->base;
4385   cur_parm_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (parm)));
4386   gcc_assert (cur_parm_size > 0);
4387
4388   if (POINTER_TYPE_P (TREE_TYPE (parm)))
4389     {
4390       by_ref = true;
4391       agg_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (TREE_TYPE (parm))));
4392     }
4393   else
4394     {
4395       by_ref = false;
4396       agg_size = cur_parm_size;
4397     }
4398
4399   if (dump_file)
4400     {
4401       struct access *acc;
4402       fprintf (dump_file, "Evaluating PARAM group sizes for ");
4403       print_generic_expr (dump_file, parm, 0);
4404       fprintf (dump_file, " (UID: %u): \n", DECL_UID (parm));
4405       for (acc = repr; acc; acc = acc->next_grp)
4406         dump_access (dump_file, acc, true);
4407     }
4408
4409   total_size = 0;
4410   new_param_count = 0;
4411
4412   for (; repr; repr = repr->next_grp)
4413     {
4414       gcc_assert (parm == repr->base);
4415
4416       /* Taking the address of a non-addressable field is verboten.  */
4417       if (by_ref && repr->non_addressable)
4418         return 0;
4419
4420       /* Do not decompose a non-BLKmode param in a way that would
4421          create BLKmode params.  Especially for by-reference passing
4422          (thus, pointer-type param) this is hardly worthwhile.  */
4423       if (DECL_MODE (parm) != BLKmode
4424           && TYPE_MODE (repr->type) == BLKmode)
4425         return 0;
4426
4427       if (!by_ref || (!repr->grp_maybe_modified
4428                       && !repr->grp_not_necessarilly_dereferenced))
4429         total_size += repr->size;
4430       else
4431         total_size += cur_parm_size;
4432
4433       new_param_count++;
4434     }
4435
4436   gcc_assert (new_param_count > 0);
4437
4438   if (optimize_function_for_size_p (cfun))
4439     parm_size_limit = cur_parm_size;
4440   else
4441     parm_size_limit = (PARAM_VALUE (PARAM_IPA_SRA_PTR_GROWTH_FACTOR)
4442                        * cur_parm_size);
4443
4444   if (total_size < agg_size
4445       && total_size <= parm_size_limit)
4446     {
4447       if (dump_file)
4448         fprintf (dump_file, "    ....will be split into %i components\n",
4449                  new_param_count);
4450       return new_param_count;
4451     }
4452   else
4453     return 0;
4454 }
4455
4456 /* The order of the following enums is important, we need to do extra work for
4457    UNUSED_PARAMS, BY_VAL_ACCESSES and UNMODIF_BY_REF_ACCESSES.  */
4458 enum ipa_splicing_result { NO_GOOD_ACCESS, UNUSED_PARAMS, BY_VAL_ACCESSES,
4459                           MODIF_BY_REF_ACCESSES, UNMODIF_BY_REF_ACCESSES };
4460
4461 /* Identify representatives of all accesses to all candidate parameters for
4462    IPA-SRA.  Return result based on what representatives have been found. */
4463
4464 static enum ipa_splicing_result
4465 splice_all_param_accesses (vec<access_p> &representatives)
4466 {
4467   enum ipa_splicing_result result = NO_GOOD_ACCESS;
4468   tree parm;
4469   struct access *repr;
4470
4471   representatives.create (func_param_count);
4472
4473   for (parm = DECL_ARGUMENTS (current_function_decl);
4474        parm;
4475        parm = DECL_CHAIN (parm))
4476     {
4477       if (is_unused_scalar_param (parm))
4478         {
4479           representatives.quick_push (&no_accesses_representant);
4480           if (result == NO_GOOD_ACCESS)
4481             result = UNUSED_PARAMS;
4482         }
4483       else if (POINTER_TYPE_P (TREE_TYPE (parm))
4484                && is_gimple_reg_type (TREE_TYPE (TREE_TYPE (parm)))
4485                && bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
4486         {
4487           repr = unmodified_by_ref_scalar_representative (parm);
4488           representatives.quick_push (repr);
4489           if (repr)
4490             result = UNMODIF_BY_REF_ACCESSES;
4491         }
4492       else if (bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
4493         {
4494           bool ro_grp = false;
4495           repr = splice_param_accesses (parm, &ro_grp);
4496           representatives.quick_push (repr);
4497
4498           if (repr && !no_accesses_p (repr))
4499             {
4500               if (POINTER_TYPE_P (TREE_TYPE (parm)))
4501                 {
4502                   if (ro_grp)
4503                     result = UNMODIF_BY_REF_ACCESSES;
4504                   else if (result < MODIF_BY_REF_ACCESSES)
4505                     result = MODIF_BY_REF_ACCESSES;
4506                 }
4507               else if (result < BY_VAL_ACCESSES)
4508                 result = BY_VAL_ACCESSES;
4509             }
4510           else if (no_accesses_p (repr) && (result == NO_GOOD_ACCESS))
4511             result = UNUSED_PARAMS;
4512         }
4513       else
4514         representatives.quick_push (NULL);
4515     }
4516
4517   if (result == NO_GOOD_ACCESS)
4518     {
4519       representatives.release ();
4520       return NO_GOOD_ACCESS;
4521     }
4522
4523   return result;
4524 }
4525
4526 /* Return the index of BASE in PARMS.  Abort if it is not found.  */
4527
4528 static inline int
4529 get_param_index (tree base, vec<tree> parms)
4530 {
4531   int i, len;
4532
4533   len = parms.length ();
4534   for (i = 0; i < len; i++)
4535     if (parms[i] == base)
4536       return i;
4537   gcc_unreachable ();
4538 }
4539
4540 /* Convert the decisions made at the representative level into compact
4541    parameter adjustments.  REPRESENTATIVES are pointers to first
4542    representatives of each param accesses, ADJUSTMENTS_COUNT is the expected
4543    final number of adjustments.  */
4544
4545 static ipa_parm_adjustment_vec
4546 turn_representatives_into_adjustments (vec<access_p> representatives,
4547                                        int adjustments_count)
4548 {
4549   vec<tree> parms;
4550   ipa_parm_adjustment_vec adjustments;
4551   tree parm;
4552   int i;
4553
4554   gcc_assert (adjustments_count > 0);
4555   parms = ipa_get_vector_of_formal_parms (current_function_decl);
4556   adjustments.create (adjustments_count);
4557   parm = DECL_ARGUMENTS (current_function_decl);
4558   for (i = 0; i < func_param_count; i++, parm = DECL_CHAIN (parm))
4559     {
4560       struct access *repr = representatives[i];
4561
4562       if (!repr || no_accesses_p (repr))
4563         {
4564           struct ipa_parm_adjustment adj;
4565
4566           memset (&adj, 0, sizeof (adj));
4567           adj.base_index = get_param_index (parm, parms);
4568           adj.base = parm;
4569           if (!repr)
4570             adj.op = IPA_PARM_OP_COPY;
4571           else
4572             adj.op = IPA_PARM_OP_REMOVE;
4573           adj.arg_prefix = "ISRA";
4574           adjustments.quick_push (adj);
4575         }
4576       else
4577         {
4578           struct ipa_parm_adjustment adj;
4579           int index = get_param_index (parm, parms);
4580
4581           for (; repr; repr = repr->next_grp)
4582             {
4583               memset (&adj, 0, sizeof (adj));
4584               gcc_assert (repr->base == parm);
4585               adj.base_index = index;
4586               adj.base = repr->base;
4587               adj.type = repr->type;
4588               adj.alias_ptr_type = reference_alias_ptr_type (repr->expr);
4589               adj.offset = repr->offset;
4590               adj.reverse = repr->reverse;
4591               adj.by_ref = (POINTER_TYPE_P (TREE_TYPE (repr->base))
4592                             && (repr->grp_maybe_modified
4593                                 || repr->grp_not_necessarilly_dereferenced));
4594               adj.arg_prefix = "ISRA";
4595               adjustments.quick_push (adj);
4596             }
4597         }
4598     }
4599   parms.release ();
4600   return adjustments;
4601 }
4602
4603 /* Analyze the collected accesses and produce a plan what to do with the
4604    parameters in the form of adjustments, NULL meaning nothing.  */
4605
4606 static ipa_parm_adjustment_vec
4607 analyze_all_param_acesses (void)
4608 {
4609   enum ipa_splicing_result repr_state;
4610   bool proceed = false;
4611   int i, adjustments_count = 0;
4612   vec<access_p> representatives;
4613   ipa_parm_adjustment_vec adjustments;
4614
4615   repr_state = splice_all_param_accesses (representatives);
4616   if (repr_state == NO_GOOD_ACCESS)
4617     return ipa_parm_adjustment_vec ();
4618
4619   /* If there are any parameters passed by reference which are not modified
4620      directly, we need to check whether they can be modified indirectly.  */
4621   if (repr_state == UNMODIF_BY_REF_ACCESSES)
4622     {
4623       analyze_caller_dereference_legality (representatives);
4624       analyze_modified_params (representatives);
4625     }
4626
4627   for (i = 0; i < func_param_count; i++)
4628     {
4629       struct access *repr = representatives[i];
4630
4631       if (repr && !no_accesses_p (repr))
4632         {
4633           if (repr->grp_scalar_ptr)
4634             {
4635               adjustments_count++;
4636               if (repr->grp_not_necessarilly_dereferenced
4637                   || repr->grp_maybe_modified)
4638                 representatives[i] = NULL;
4639               else
4640                 {
4641                   proceed = true;
4642                   sra_stats.scalar_by_ref_to_by_val++;
4643                 }
4644             }
4645           else
4646             {
4647               int new_components = decide_one_param_reduction (repr);
4648
4649               if (new_components == 0)
4650                 {
4651                   representatives[i] = NULL;
4652                   adjustments_count++;
4653                 }
4654               else
4655                 {
4656                   adjustments_count += new_components;
4657                   sra_stats.aggregate_params_reduced++;
4658                   sra_stats.param_reductions_created += new_components;
4659                   proceed = true;
4660                 }
4661             }
4662         }
4663       else
4664         {
4665           if (no_accesses_p (repr))
4666             {
4667               proceed = true;
4668               sra_stats.deleted_unused_parameters++;
4669             }
4670           adjustments_count++;
4671         }
4672     }
4673
4674   if (!proceed && dump_file)
4675     fprintf (dump_file, "NOT proceeding to change params.\n");
4676
4677   if (proceed)
4678     adjustments = turn_representatives_into_adjustments (representatives,
4679                                                          adjustments_count);
4680   else
4681     adjustments = ipa_parm_adjustment_vec ();
4682
4683   representatives.release ();
4684   return adjustments;
4685 }
4686
4687 /* If a parameter replacement identified by ADJ does not yet exist in the form
4688    of declaration, create it and record it, otherwise return the previously
4689    created one.  */
4690
4691 static tree
4692 get_replaced_param_substitute (struct ipa_parm_adjustment *adj)
4693 {
4694   tree repl;
4695   if (!adj->new_ssa_base)
4696     {
4697       char *pretty_name = make_fancy_name (adj->base);
4698
4699       repl = create_tmp_reg (TREE_TYPE (adj->base), "ISR");
4700       DECL_NAME (repl) = get_identifier (pretty_name);
4701       obstack_free (&name_obstack, pretty_name);
4702
4703       adj->new_ssa_base = repl;
4704     }
4705   else
4706     repl = adj->new_ssa_base;
4707   return repl;
4708 }
4709
4710 /* Find the first adjustment for a particular parameter BASE in a vector of
4711    ADJUSTMENTS which is not a copy_param.  Return NULL if there is no such
4712    adjustment. */
4713
4714 static struct ipa_parm_adjustment *
4715 get_adjustment_for_base (ipa_parm_adjustment_vec adjustments, tree base)
4716 {
4717   int i, len;
4718
4719   len = adjustments.length ();
4720   for (i = 0; i < len; i++)
4721     {
4722       struct ipa_parm_adjustment *adj;
4723
4724       adj = &adjustments[i];
4725       if (adj->op != IPA_PARM_OP_COPY && adj->base == base)
4726         return adj;
4727     }
4728
4729   return NULL;
4730 }
4731
4732 /* If OLD_NAME, which is being defined by statement STMT, is an SSA_NAME of a
4733    parameter which is to be removed because its value is not used, create a new
4734    SSA_NAME relating to a replacement VAR_DECL, replace all uses of the
4735    original with it and return it.  If there is no need to re-map, return NULL.
4736    ADJUSTMENTS is a pointer to a vector of IPA-SRA adjustments.  */
4737
4738 static tree
4739 replace_removed_params_ssa_names (tree old_name, gimple *stmt,
4740                                   ipa_parm_adjustment_vec adjustments)
4741 {
4742   struct ipa_parm_adjustment *adj;
4743   tree decl, repl, new_name;
4744
4745   if (TREE_CODE (old_name) != SSA_NAME)
4746     return NULL;
4747
4748   decl = SSA_NAME_VAR (old_name);
4749   if (decl == NULL_TREE
4750       || TREE_CODE (decl) != PARM_DECL)
4751     return NULL;
4752
4753   adj = get_adjustment_for_base (adjustments, decl);
4754   if (!adj)
4755     return NULL;
4756
4757   repl = get_replaced_param_substitute (adj);
4758   new_name = make_ssa_name (repl, stmt);
4759
4760   if (dump_file)
4761     {
4762       fprintf (dump_file, "replacing an SSA name of a removed param ");
4763       print_generic_expr (dump_file, old_name, 0);
4764       fprintf (dump_file, " with ");
4765       print_generic_expr (dump_file, new_name, 0);
4766       fprintf (dump_file, "\n");
4767     }
4768
4769   replace_uses_by (old_name, new_name);
4770   return new_name;
4771 }
4772
4773 /* If the statement STMT contains any expressions that need to replaced with a
4774    different one as noted by ADJUSTMENTS, do so.  Handle any potential type
4775    incompatibilities (GSI is used to accommodate conversion statements and must
4776    point to the statement).  Return true iff the statement was modified.  */
4777
4778 static bool
4779 sra_ipa_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi,
4780                        ipa_parm_adjustment_vec adjustments)
4781 {
4782   tree *lhs_p, *rhs_p;
4783   bool any;
4784
4785   if (!gimple_assign_single_p (stmt))
4786     return false;
4787
4788   rhs_p = gimple_assign_rhs1_ptr (stmt);
4789   lhs_p = gimple_assign_lhs_ptr (stmt);
4790
4791   any = ipa_modify_expr (rhs_p, false, adjustments);
4792   any |= ipa_modify_expr (lhs_p, false, adjustments);
4793   if (any)
4794     {
4795       tree new_rhs = NULL_TREE;
4796
4797       if (!useless_type_conversion_p (TREE_TYPE (*lhs_p), TREE_TYPE (*rhs_p)))
4798         {
4799           if (TREE_CODE (*rhs_p) == CONSTRUCTOR)
4800             {
4801               /* V_C_Es of constructors can cause trouble (PR 42714).  */
4802               if (is_gimple_reg_type (TREE_TYPE (*lhs_p)))
4803                 *rhs_p = build_zero_cst (TREE_TYPE (*lhs_p));
4804               else
4805                 *rhs_p = build_constructor (TREE_TYPE (*lhs_p),
4806                                             NULL);
4807             }
4808           else
4809             new_rhs = fold_build1_loc (gimple_location (stmt),
4810                                        VIEW_CONVERT_EXPR, TREE_TYPE (*lhs_p),
4811                                        *rhs_p);
4812         }
4813       else if (REFERENCE_CLASS_P (*rhs_p)
4814                && is_gimple_reg_type (TREE_TYPE (*lhs_p))
4815                && !is_gimple_reg (*lhs_p))
4816         /* This can happen when an assignment in between two single field
4817            structures is turned into an assignment in between two pointers to
4818            scalars (PR 42237).  */
4819         new_rhs = *rhs_p;
4820
4821       if (new_rhs)
4822         {
4823           tree tmp = force_gimple_operand_gsi (gsi, new_rhs, true, NULL_TREE,
4824                                                true, GSI_SAME_STMT);
4825
4826           gimple_assign_set_rhs_from_tree (gsi, tmp);
4827         }
4828
4829       return true;
4830     }
4831
4832   return false;
4833 }
4834
4835 /* Traverse the function body and all modifications as described in
4836    ADJUSTMENTS.  Return true iff the CFG has been changed.  */
4837
4838 bool
4839 ipa_sra_modify_function_body (ipa_parm_adjustment_vec adjustments)
4840 {
4841   bool cfg_changed = false;
4842   basic_block bb;
4843
4844   FOR_EACH_BB_FN (bb, cfun)
4845     {
4846       gimple_stmt_iterator gsi;
4847
4848       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
4849         {
4850           gphi *phi = as_a <gphi *> (gsi_stmt (gsi));
4851           tree new_lhs, old_lhs = gimple_phi_result (phi);
4852           new_lhs = replace_removed_params_ssa_names (old_lhs, phi, adjustments);
4853           if (new_lhs)
4854             {
4855               gimple_phi_set_result (phi, new_lhs);
4856               release_ssa_name (old_lhs);
4857             }
4858         }
4859
4860       gsi = gsi_start_bb (bb);
4861       while (!gsi_end_p (gsi))
4862         {
4863           gimple *stmt = gsi_stmt (gsi);
4864           bool modified = false;
4865           tree *t;
4866           unsigned i;
4867
4868           switch (gimple_code (stmt))
4869             {
4870             case GIMPLE_RETURN:
4871               t = gimple_return_retval_ptr (as_a <greturn *> (stmt));
4872               if (*t != NULL_TREE)
4873                 modified |= ipa_modify_expr (t, true, adjustments);
4874               break;
4875
4876             case GIMPLE_ASSIGN:
4877               modified |= sra_ipa_modify_assign (stmt, &gsi, adjustments);
4878               break;
4879
4880             case GIMPLE_CALL:
4881               /* Operands must be processed before the lhs.  */
4882               for (i = 0; i < gimple_call_num_args (stmt); i++)
4883                 {
4884                   t = gimple_call_arg_ptr (stmt, i);
4885                   modified |= ipa_modify_expr (t, true, adjustments);
4886                 }
4887
4888               if (gimple_call_lhs (stmt))
4889                 {
4890                   t = gimple_call_lhs_ptr (stmt);
4891                   modified |= ipa_modify_expr (t, false, adjustments);
4892                 }
4893               break;
4894
4895             case GIMPLE_ASM:
4896               {
4897                 gasm *asm_stmt = as_a <gasm *> (stmt);
4898                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
4899                   {
4900                     t = &TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
4901                     modified |= ipa_modify_expr (t, true, adjustments);
4902                   }
4903                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
4904                   {
4905                     t = &TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
4906                     modified |= ipa_modify_expr (t, false, adjustments);
4907                   }
4908               }
4909               break;
4910
4911             default:
4912               break;
4913             }
4914
4915           def_operand_p defp;
4916           ssa_op_iter iter;
4917           FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_DEF)
4918             {
4919               tree old_def = DEF_FROM_PTR (defp);
4920               if (tree new_def = replace_removed_params_ssa_names (old_def, stmt,
4921                                                                    adjustments))
4922                 {
4923                   SET_DEF (defp, new_def);
4924                   release_ssa_name (old_def);
4925                   modified = true;
4926                 }
4927             }
4928
4929           if (modified)
4930             {
4931               update_stmt (stmt);
4932               if (maybe_clean_eh_stmt (stmt)
4933                   && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
4934                 cfg_changed = true;
4935             }
4936           gsi_next (&gsi);
4937         }
4938     }
4939
4940   return cfg_changed;
4941 }
4942
4943 /* Call gimple_debug_bind_reset_value on all debug statements describing
4944    gimple register parameters that are being removed or replaced.  */
4945
4946 static void
4947 sra_ipa_reset_debug_stmts (ipa_parm_adjustment_vec adjustments)
4948 {
4949   int i, len;
4950   gimple_stmt_iterator *gsip = NULL, gsi;
4951
4952   if (MAY_HAVE_DEBUG_STMTS && single_succ_p (ENTRY_BLOCK_PTR_FOR_FN (cfun)))
4953     {
4954       gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
4955       gsip = &gsi;
4956     }
4957   len = adjustments.length ();
4958   for (i = 0; i < len; i++)
4959     {
4960       struct ipa_parm_adjustment *adj;
4961       imm_use_iterator ui;
4962       gimple *stmt;
4963       gdebug *def_temp;
4964       tree name, vexpr, copy = NULL_TREE;
4965       use_operand_p use_p;
4966
4967       adj = &adjustments[i];
4968       if (adj->op == IPA_PARM_OP_COPY || !is_gimple_reg (adj->base))
4969         continue;
4970       name = ssa_default_def (cfun, adj->base);
4971       vexpr = NULL;
4972       if (name)
4973         FOR_EACH_IMM_USE_STMT (stmt, ui, name)
4974           {
4975             if (gimple_clobber_p (stmt))
4976               {
4977                 gimple_stmt_iterator cgsi = gsi_for_stmt (stmt);
4978                 unlink_stmt_vdef (stmt);
4979                 gsi_remove (&cgsi, true);
4980                 release_defs (stmt);
4981                 continue;
4982               }
4983             /* All other users must have been removed by
4984                ipa_sra_modify_function_body.  */
4985             gcc_assert (is_gimple_debug (stmt));
4986             if (vexpr == NULL && gsip != NULL)
4987               {
4988                 gcc_assert (TREE_CODE (adj->base) == PARM_DECL);
4989                 vexpr = make_node (DEBUG_EXPR_DECL);
4990                 def_temp = gimple_build_debug_source_bind (vexpr, adj->base,
4991                                                            NULL);
4992                 DECL_ARTIFICIAL (vexpr) = 1;
4993                 TREE_TYPE (vexpr) = TREE_TYPE (name);
4994                 DECL_MODE (vexpr) = DECL_MODE (adj->base);
4995                 gsi_insert_before (gsip, def_temp, GSI_SAME_STMT);
4996               }
4997             if (vexpr)
4998               {
4999                 FOR_EACH_IMM_USE_ON_STMT (use_p, ui)
5000                   SET_USE (use_p, vexpr);
5001               }
5002             else
5003               gimple_debug_bind_reset_value (stmt);
5004             update_stmt (stmt);
5005           }
5006       /* Create a VAR_DECL for debug info purposes.  */
5007       if (!DECL_IGNORED_P (adj->base))
5008         {
5009           copy = build_decl (DECL_SOURCE_LOCATION (current_function_decl),
5010                              VAR_DECL, DECL_NAME (adj->base),
5011                              TREE_TYPE (adj->base));
5012           if (DECL_PT_UID_SET_P (adj->base))
5013             SET_DECL_PT_UID (copy, DECL_PT_UID (adj->base));
5014           TREE_ADDRESSABLE (copy) = TREE_ADDRESSABLE (adj->base);
5015           TREE_READONLY (copy) = TREE_READONLY (adj->base);
5016           TREE_THIS_VOLATILE (copy) = TREE_THIS_VOLATILE (adj->base);
5017           DECL_GIMPLE_REG_P (copy) = DECL_GIMPLE_REG_P (adj->base);
5018           DECL_ARTIFICIAL (copy) = DECL_ARTIFICIAL (adj->base);
5019           DECL_IGNORED_P (copy) = DECL_IGNORED_P (adj->base);
5020           DECL_ABSTRACT_ORIGIN (copy) = DECL_ORIGIN (adj->base);
5021           DECL_SEEN_IN_BIND_EXPR_P (copy) = 1;
5022           SET_DECL_RTL (copy, 0);
5023           TREE_USED (copy) = 1;
5024           DECL_CONTEXT (copy) = current_function_decl;
5025           add_local_decl (cfun, copy);
5026           DECL_CHAIN (copy) =
5027             BLOCK_VARS (DECL_INITIAL (current_function_decl));
5028           BLOCK_VARS (DECL_INITIAL (current_function_decl)) = copy;
5029         }
5030       if (gsip != NULL && copy && target_for_debug_bind (adj->base))
5031         {
5032           gcc_assert (TREE_CODE (adj->base) == PARM_DECL);
5033           if (vexpr)
5034             def_temp = gimple_build_debug_bind (copy, vexpr, NULL);
5035           else
5036             def_temp = gimple_build_debug_source_bind (copy, adj->base,
5037                                                        NULL);
5038           gsi_insert_before (gsip, def_temp, GSI_SAME_STMT);
5039         }
5040     }
5041 }
5042
5043 /* Return false if all callers have at least as many actual arguments as there
5044    are formal parameters in the current function and that their types
5045    match.  */
5046
5047 static bool
5048 some_callers_have_mismatched_arguments_p (struct cgraph_node *node,
5049                                           void *data ATTRIBUTE_UNUSED)
5050 {
5051   struct cgraph_edge *cs;
5052   for (cs = node->callers; cs; cs = cs->next_caller)
5053     if (!cs->call_stmt || !callsite_arguments_match_p (cs->call_stmt))
5054       return true;
5055
5056   return false;
5057 }
5058
5059 /* Return false if all callers have vuse attached to a call statement.  */
5060
5061 static bool
5062 some_callers_have_no_vuse_p (struct cgraph_node *node,
5063                              void *data ATTRIBUTE_UNUSED)
5064 {
5065   struct cgraph_edge *cs;
5066   for (cs = node->callers; cs; cs = cs->next_caller)
5067     if (!cs->call_stmt || !gimple_vuse (cs->call_stmt))
5068       return true;
5069
5070   return false;
5071 }
5072
5073 /* Convert all callers of NODE.  */
5074
5075 static bool
5076 convert_callers_for_node (struct cgraph_node *node,
5077                           void *data)
5078 {
5079   ipa_parm_adjustment_vec *adjustments = (ipa_parm_adjustment_vec *) data;
5080   bitmap recomputed_callers = BITMAP_ALLOC (NULL);
5081   struct cgraph_edge *cs;
5082
5083   for (cs = node->callers; cs; cs = cs->next_caller)
5084     {
5085       push_cfun (DECL_STRUCT_FUNCTION (cs->caller->decl));
5086
5087       if (dump_file)
5088         fprintf (dump_file, "Adjusting call %s/%i -> %s/%i\n",
5089                  xstrdup_for_dump (cs->caller->name ()),
5090                  cs->caller->order,
5091                  xstrdup_for_dump (cs->callee->name ()),
5092                  cs->callee->order);
5093
5094       ipa_modify_call_arguments (cs, cs->call_stmt, *adjustments);
5095
5096       pop_cfun ();
5097     }
5098
5099   for (cs = node->callers; cs; cs = cs->next_caller)
5100     if (bitmap_set_bit (recomputed_callers, cs->caller->uid)
5101         && gimple_in_ssa_p (DECL_STRUCT_FUNCTION (cs->caller->decl)))
5102       compute_inline_parameters (cs->caller, true);
5103   BITMAP_FREE (recomputed_callers);
5104
5105   return true;
5106 }
5107
5108 /* Convert all callers of NODE to pass parameters as given in ADJUSTMENTS.  */
5109
5110 static void
5111 convert_callers (struct cgraph_node *node, tree old_decl,
5112                  ipa_parm_adjustment_vec adjustments)
5113 {
5114   basic_block this_block;
5115
5116   node->call_for_symbol_and_aliases (convert_callers_for_node,
5117                                      &adjustments, false);
5118
5119   if (!encountered_recursive_call)
5120     return;
5121
5122   FOR_EACH_BB_FN (this_block, cfun)
5123     {
5124       gimple_stmt_iterator gsi;
5125
5126       for (gsi = gsi_start_bb (this_block); !gsi_end_p (gsi); gsi_next (&gsi))
5127         {
5128           gcall *stmt;
5129           tree call_fndecl;
5130           stmt = dyn_cast <gcall *> (gsi_stmt (gsi));
5131           if (!stmt)
5132             continue;
5133           call_fndecl = gimple_call_fndecl (stmt);
5134           if (call_fndecl == old_decl)
5135             {
5136               if (dump_file)
5137                 fprintf (dump_file, "Adjusting recursive call");
5138               gimple_call_set_fndecl (stmt, node->decl);
5139               ipa_modify_call_arguments (NULL, stmt, adjustments);
5140             }
5141         }
5142     }
5143
5144   return;
5145 }
5146
5147 /* Perform all the modification required in IPA-SRA for NODE to have parameters
5148    as given in ADJUSTMENTS.  Return true iff the CFG has been changed.  */
5149
5150 static bool
5151 modify_function (struct cgraph_node *node, ipa_parm_adjustment_vec adjustments)
5152 {
5153   struct cgraph_node *new_node;
5154   bool cfg_changed;
5155
5156   cgraph_edge::rebuild_edges ();
5157   free_dominance_info (CDI_DOMINATORS);
5158   pop_cfun ();
5159
5160   /* This must be done after rebuilding cgraph edges for node above.
5161      Otherwise any recursive calls to node that are recorded in
5162      redirect_callers will be corrupted.  */
5163   vec<cgraph_edge *> redirect_callers = node->collect_callers ();
5164   new_node = node->create_version_clone_with_body (redirect_callers, NULL,
5165                                                    NULL, false, NULL, NULL,
5166                                                    "isra");
5167   redirect_callers.release ();
5168
5169   push_cfun (DECL_STRUCT_FUNCTION (new_node->decl));
5170   ipa_modify_formal_parameters (current_function_decl, adjustments);
5171   cfg_changed = ipa_sra_modify_function_body (adjustments);
5172   sra_ipa_reset_debug_stmts (adjustments);
5173   convert_callers (new_node, node->decl, adjustments);
5174   new_node->make_local ();
5175   return cfg_changed;
5176 }
5177
5178 /* Means of communication between ipa_sra_check_caller and
5179    ipa_sra_preliminary_function_checks.  */
5180
5181 struct ipa_sra_check_caller_data
5182 {
5183   bool has_callers;
5184   bool bad_arg_alignment;
5185   bool has_thunk;
5186 };
5187
5188 /* If NODE has a caller, mark that fact in DATA which is pointer to
5189    ipa_sra_check_caller_data.  Also check all aggregate arguments in all known
5190    calls if they are unit aligned and if not, set the appropriate flag in DATA
5191    too. */
5192
5193 static bool
5194 ipa_sra_check_caller (struct cgraph_node *node, void *data)
5195 {
5196   if (!node->callers)
5197     return false;
5198
5199   struct ipa_sra_check_caller_data *iscc;
5200   iscc = (struct ipa_sra_check_caller_data *) data;
5201   iscc->has_callers = true;
5202
5203   for (cgraph_edge *cs = node->callers; cs; cs = cs->next_caller)
5204     {
5205       if (cs->caller->thunk.thunk_p)
5206         {
5207           iscc->has_thunk = true;
5208           return true;
5209         }
5210       gimple *call_stmt = cs->call_stmt;
5211       unsigned count = gimple_call_num_args (call_stmt);
5212       for (unsigned i = 0; i < count; i++)
5213         {
5214           tree arg = gimple_call_arg (call_stmt, i);
5215           if (is_gimple_reg (arg))
5216               continue;
5217
5218           tree offset;
5219           HOST_WIDE_INT bitsize, bitpos;
5220           machine_mode mode;
5221           int unsignedp, reversep, volatilep = 0;
5222           get_inner_reference (arg, &bitsize, &bitpos, &offset, &mode,
5223                                &unsignedp, &reversep, &volatilep, false);
5224           if (bitpos % BITS_PER_UNIT)
5225             {
5226               iscc->bad_arg_alignment = true;
5227               return true;
5228             }
5229         }
5230     }
5231
5232   return false;
5233 }
5234
5235 /* Return false the function is apparently unsuitable for IPA-SRA based on it's
5236    attributes, return true otherwise.  NODE is the cgraph node of the current
5237    function.  */
5238
5239 static bool
5240 ipa_sra_preliminary_function_checks (struct cgraph_node *node)
5241 {
5242   if (!node->can_be_local_p ())
5243     {
5244       if (dump_file)
5245         fprintf (dump_file, "Function not local to this compilation unit.\n");
5246       return false;
5247     }
5248
5249   if (!node->local.can_change_signature)
5250     {
5251       if (dump_file)
5252         fprintf (dump_file, "Function can not change signature.\n");
5253       return false;
5254     }
5255
5256   if (!tree_versionable_function_p (node->decl))
5257     {
5258       if (dump_file)
5259         fprintf (dump_file, "Function is not versionable.\n");
5260       return false;
5261     }
5262
5263   if (!opt_for_fn (node->decl, optimize)
5264       || !opt_for_fn (node->decl, flag_ipa_sra))
5265     {
5266       if (dump_file)
5267         fprintf (dump_file, "Function not optimized.\n");
5268       return false;
5269     }
5270
5271   if (DECL_VIRTUAL_P (current_function_decl))
5272     {
5273       if (dump_file)
5274         fprintf (dump_file, "Function is a virtual method.\n");
5275       return false;
5276     }
5277
5278   if ((DECL_ONE_ONLY (node->decl) || DECL_EXTERNAL (node->decl))
5279       && inline_summaries->get (node)->size >= MAX_INLINE_INSNS_AUTO)
5280     {
5281       if (dump_file)
5282         fprintf (dump_file, "Function too big to be made truly local.\n");
5283       return false;
5284     }
5285
5286   if (cfun->stdarg)
5287     {
5288       if (dump_file)
5289         fprintf (dump_file, "Function uses stdarg. \n");
5290       return false;
5291     }
5292
5293   if (TYPE_ATTRIBUTES (TREE_TYPE (node->decl)))
5294     return false;
5295
5296   if (DECL_DISREGARD_INLINE_LIMITS (node->decl))
5297     {
5298       if (dump_file)
5299         fprintf (dump_file, "Always inline function will be inlined "
5300                  "anyway. \n");
5301       return false;
5302     }
5303
5304   struct ipa_sra_check_caller_data iscc;
5305   memset (&iscc, 0, sizeof(iscc));
5306   node->call_for_symbol_and_aliases (ipa_sra_check_caller, &iscc, true);
5307   if (!iscc.has_callers)
5308     {
5309       if (dump_file)
5310         fprintf (dump_file,
5311                  "Function has no callers in this compilation unit.\n");
5312       return false;
5313     }
5314
5315   if (iscc.bad_arg_alignment)
5316     {
5317       if (dump_file)
5318         fprintf (dump_file,
5319                  "A function call has an argument with non-unit alignment.\n");
5320       return false;
5321     }
5322
5323   if (iscc.has_thunk)
5324     {
5325       if (dump_file)
5326         fprintf (dump_file,
5327                  "A has thunk.\n");
5328       return false;
5329     }
5330
5331   return true;
5332 }
5333
5334 /* Perform early interprocedural SRA.  */
5335
5336 static unsigned int
5337 ipa_early_sra (void)
5338 {
5339   struct cgraph_node *node = cgraph_node::get (current_function_decl);
5340   ipa_parm_adjustment_vec adjustments;
5341   int ret = 0;
5342
5343   if (!ipa_sra_preliminary_function_checks (node))
5344     return 0;
5345
5346   sra_initialize ();
5347   sra_mode = SRA_MODE_EARLY_IPA;
5348
5349   if (!find_param_candidates ())
5350     {
5351       if (dump_file)
5352         fprintf (dump_file, "Function has no IPA-SRA candidates.\n");
5353       goto simple_out;
5354     }
5355
5356   if (node->call_for_symbol_and_aliases
5357        (some_callers_have_mismatched_arguments_p, NULL, true))
5358     {
5359       if (dump_file)
5360         fprintf (dump_file, "There are callers with insufficient number of "
5361                  "arguments or arguments with type mismatches.\n");
5362       goto simple_out;
5363     }
5364
5365   if (node->call_for_symbol_and_aliases
5366        (some_callers_have_no_vuse_p, NULL, true))
5367     {
5368       if (dump_file)
5369         fprintf (dump_file, "There are callers with no VUSE attached "
5370                  "to a call stmt.\n");
5371       goto simple_out;
5372     }
5373
5374   bb_dereferences = XCNEWVEC (HOST_WIDE_INT,
5375                                  func_param_count
5376                                  * last_basic_block_for_fn (cfun));
5377   final_bbs = BITMAP_ALLOC (NULL);
5378
5379   scan_function ();
5380   if (encountered_apply_args)
5381     {
5382       if (dump_file)
5383         fprintf (dump_file, "Function calls  __builtin_apply_args().\n");
5384       goto out;
5385     }
5386
5387   if (encountered_unchangable_recursive_call)
5388     {
5389       if (dump_file)
5390         fprintf (dump_file, "Function calls itself with insufficient "
5391                  "number of arguments.\n");
5392       goto out;
5393     }
5394
5395   adjustments = analyze_all_param_acesses ();
5396   if (!adjustments.exists ())
5397     goto out;
5398   if (dump_file)
5399     ipa_dump_param_adjustments (dump_file, adjustments, current_function_decl);
5400
5401   if (modify_function (node, adjustments))
5402     ret = TODO_update_ssa | TODO_cleanup_cfg;
5403   else
5404     ret = TODO_update_ssa;
5405   adjustments.release ();
5406
5407   statistics_counter_event (cfun, "Unused parameters deleted",
5408                             sra_stats.deleted_unused_parameters);
5409   statistics_counter_event (cfun, "Scalar parameters converted to by-value",
5410                             sra_stats.scalar_by_ref_to_by_val);
5411   statistics_counter_event (cfun, "Aggregate parameters broken up",
5412                             sra_stats.aggregate_params_reduced);
5413   statistics_counter_event (cfun, "Aggregate parameter components created",
5414                             sra_stats.param_reductions_created);
5415
5416  out:
5417   BITMAP_FREE (final_bbs);
5418   free (bb_dereferences);
5419  simple_out:
5420   sra_deinitialize ();
5421   return ret;
5422 }
5423
5424 namespace {
5425
5426 const pass_data pass_data_early_ipa_sra =
5427 {
5428   GIMPLE_PASS, /* type */
5429   "eipa_sra", /* name */
5430   OPTGROUP_NONE, /* optinfo_flags */
5431   TV_IPA_SRA, /* tv_id */
5432   0, /* properties_required */
5433   0, /* properties_provided */
5434   0, /* properties_destroyed */
5435   0, /* todo_flags_start */
5436   TODO_dump_symtab, /* todo_flags_finish */
5437 };
5438
5439 class pass_early_ipa_sra : public gimple_opt_pass
5440 {
5441 public:
5442   pass_early_ipa_sra (gcc::context *ctxt)
5443     : gimple_opt_pass (pass_data_early_ipa_sra, ctxt)
5444   {}
5445
5446   /* opt_pass methods: */
5447   virtual bool gate (function *) { return flag_ipa_sra && dbg_cnt (eipa_sra); }
5448   virtual unsigned int execute (function *) { return ipa_early_sra (); }
5449
5450 }; // class pass_early_ipa_sra
5451
5452 } // anon namespace
5453
5454 gimple_opt_pass *
5455 make_pass_early_ipa_sra (gcc::context *ctxt)
5456 {
5457   return new pass_early_ipa_sra (ctxt);
5458 }