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 (prev_base),
1677                            base_offset + offset / BITS_PER_UNIT);
1678       base = build_fold_addr_expr (unshare_expr (base));
1679     }
1680
1681   misalign = (misalign + offset) & (align - 1);
1682   if (misalign != 0)
1683     align = (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            || constant_decl_p (root->base))
2432     root->grp_unscalarized_data = 1; /* not covered and written to */
2433   return sth_created;
2434 }
2435
2436 /* Analyze all access trees linked by next_grp by the means of
2437    analyze_access_subtree.  */
2438 static bool
2439 analyze_access_trees (struct access *access)
2440 {
2441   bool ret = false;
2442
2443   while (access)
2444     {
2445       if (analyze_access_subtree (access, NULL, true))
2446         ret = true;
2447       access = access->next_grp;
2448     }
2449
2450   return ret;
2451 }
2452
2453 /* Return true iff a potential new child of LACC at offset OFFSET and with size
2454    SIZE would conflict with an already existing one.  If exactly such a child
2455    already exists in LACC, store a pointer to it in EXACT_MATCH.  */
2456
2457 static bool
2458 child_would_conflict_in_lacc (struct access *lacc, HOST_WIDE_INT norm_offset,
2459                               HOST_WIDE_INT size, struct access **exact_match)
2460 {
2461   struct access *child;
2462
2463   for (child = lacc->first_child; child; child = child->next_sibling)
2464     {
2465       if (child->offset == norm_offset && child->size == size)
2466         {
2467           *exact_match = child;
2468           return true;
2469         }
2470
2471       if (child->offset < norm_offset + size
2472           && child->offset + child->size > norm_offset)
2473         return true;
2474     }
2475
2476   return false;
2477 }
2478
2479 /* Create a new child access of PARENT, with all properties just like MODEL
2480    except for its offset and with its grp_write false and grp_read true.
2481    Return the new access or NULL if it cannot be created.  Note that this access
2482    is created long after all splicing and sorting, it's not located in any
2483    access vector and is automatically a representative of its group.  */
2484
2485 static struct access *
2486 create_artificial_child_access (struct access *parent, struct access *model,
2487                                 HOST_WIDE_INT new_offset)
2488 {
2489   struct access **child;
2490   tree expr = parent->base;
2491
2492   gcc_assert (!model->grp_unscalarizable_region);
2493
2494   struct access *access = access_pool.allocate ();
2495   memset (access, 0, sizeof (struct access));
2496   if (!build_user_friendly_ref_for_offset (&expr, TREE_TYPE (expr), new_offset,
2497                                            model->type))
2498     {
2499       access->grp_no_warning = true;
2500       expr = build_ref_for_model (EXPR_LOCATION (parent->base), parent->base,
2501                                   new_offset, model, NULL, false);
2502     }
2503
2504   access->base = parent->base;
2505   access->expr = expr;
2506   access->offset = new_offset;
2507   access->size = model->size;
2508   access->type = model->type;
2509   access->grp_write = true;
2510   access->grp_read = false;
2511   access->reverse = model->reverse;
2512
2513   child = &parent->first_child;
2514   while (*child && (*child)->offset < new_offset)
2515     child = &(*child)->next_sibling;
2516
2517   access->next_sibling = *child;
2518   *child = access;
2519
2520   return access;
2521 }
2522
2523
2524 /* Propagate all subaccesses of RACC across an assignment link to LACC. Return
2525    true if any new subaccess was created.  Additionally, if RACC is a scalar
2526    access but LACC is not, change the type of the latter, if possible.  */
2527
2528 static bool
2529 propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
2530 {
2531   struct access *rchild;
2532   HOST_WIDE_INT norm_delta = lacc->offset - racc->offset;
2533   bool ret = false;
2534
2535   if (is_gimple_reg_type (lacc->type)
2536       || lacc->grp_unscalarizable_region
2537       || racc->grp_unscalarizable_region)
2538     return false;
2539
2540   if (is_gimple_reg_type (racc->type))
2541     {
2542       if (!lacc->first_child && !racc->first_child)
2543         {
2544           tree t = lacc->base;
2545
2546           lacc->type = racc->type;
2547           if (build_user_friendly_ref_for_offset (&t, TREE_TYPE (t),
2548                                                   lacc->offset, racc->type))
2549             lacc->expr = t;
2550           else
2551             {
2552               lacc->expr = build_ref_for_model (EXPR_LOCATION (lacc->base),
2553                                                 lacc->base, lacc->offset,
2554                                                 racc, NULL, false);
2555               lacc->grp_no_warning = true;
2556             }
2557         }
2558       return false;
2559     }
2560
2561   for (rchild = racc->first_child; rchild; rchild = rchild->next_sibling)
2562     {
2563       struct access *new_acc = NULL;
2564       HOST_WIDE_INT norm_offset = rchild->offset + norm_delta;
2565
2566       if (rchild->grp_unscalarizable_region)
2567         continue;
2568
2569       if (child_would_conflict_in_lacc (lacc, norm_offset, rchild->size,
2570                                         &new_acc))
2571         {
2572           if (new_acc)
2573             {
2574               rchild->grp_hint = 1;
2575               new_acc->grp_hint |= new_acc->grp_read;
2576               if (rchild->first_child)
2577                 ret |= propagate_subaccesses_across_link (new_acc, rchild);
2578             }
2579           continue;
2580         }
2581
2582       rchild->grp_hint = 1;
2583       new_acc = create_artificial_child_access (lacc, rchild, norm_offset);
2584       if (new_acc)
2585         {
2586           ret = true;
2587           if (racc->first_child)
2588             propagate_subaccesses_across_link (new_acc, rchild);
2589         }
2590     }
2591
2592   return ret;
2593 }
2594
2595 /* Propagate all subaccesses across assignment links.  */
2596
2597 static void
2598 propagate_all_subaccesses (void)
2599 {
2600   while (work_queue_head)
2601     {
2602       struct access *racc = pop_access_from_work_queue ();
2603       struct assign_link *link;
2604
2605       gcc_assert (racc->first_link);
2606
2607       for (link = racc->first_link; link; link = link->next)
2608         {
2609           struct access *lacc = link->lacc;
2610
2611           if (!bitmap_bit_p (candidate_bitmap, DECL_UID (lacc->base)))
2612             continue;
2613           lacc = lacc->group_representative;
2614           if (propagate_subaccesses_across_link (lacc, racc)
2615               && lacc->first_link)
2616             add_access_to_work_queue (lacc);
2617         }
2618     }
2619 }
2620
2621 /* Go through all accesses collected throughout the (intraprocedural) analysis
2622    stage, exclude overlapping ones, identify representatives and build trees
2623    out of them, making decisions about scalarization on the way.  Return true
2624    iff there are any to-be-scalarized variables after this stage. */
2625
2626 static bool
2627 analyze_all_variable_accesses (void)
2628 {
2629   int res = 0;
2630   bitmap tmp = BITMAP_ALLOC (NULL);
2631   bitmap_iterator bi;
2632   unsigned i;
2633   bool optimize_speed_p = !optimize_function_for_size_p (cfun);
2634
2635   enum compiler_param param = optimize_speed_p
2636                         ? PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED
2637                         : PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE;
2638
2639   /* If the user didn't set PARAM_SRA_MAX_SCALARIZATION_SIZE_<...>,
2640      fall back to a target default.  */
2641   unsigned HOST_WIDE_INT max_scalarization_size
2642     = global_options_set.x_param_values[param]
2643       ? PARAM_VALUE (param)
2644       : get_move_ratio (optimize_speed_p) * UNITS_PER_WORD;
2645
2646   max_scalarization_size *= BITS_PER_UNIT;
2647
2648   EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
2649     if (bitmap_bit_p (should_scalarize_away_bitmap, i)
2650         && !bitmap_bit_p (cannot_scalarize_away_bitmap, i))
2651       {
2652         tree var = candidate (i);
2653
2654         if (TREE_CODE (var) == VAR_DECL
2655             && scalarizable_type_p (TREE_TYPE (var)))
2656           {
2657             if (tree_to_uhwi (TYPE_SIZE (TREE_TYPE (var)))
2658                 <= max_scalarization_size)
2659               {
2660                 create_total_scalarization_access (var);
2661                 completely_scalarize (var, TREE_TYPE (var), 0, var);
2662                 if (dump_file && (dump_flags & TDF_DETAILS))
2663                   {
2664                     fprintf (dump_file, "Will attempt to totally scalarize ");
2665                     print_generic_expr (dump_file, var, 0);
2666                     fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2667                   }
2668               }
2669             else if (dump_file && (dump_flags & TDF_DETAILS))
2670               {
2671                 fprintf (dump_file, "Too big to totally scalarize: ");
2672                 print_generic_expr (dump_file, var, 0);
2673                 fprintf (dump_file, " (UID: %u)\n", DECL_UID (var));
2674               }
2675           }
2676       }
2677
2678   bitmap_copy (tmp, candidate_bitmap);
2679   EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2680     {
2681       tree var = candidate (i);
2682       struct access *access;
2683
2684       access = sort_and_splice_var_accesses (var);
2685       if (!access || !build_access_trees (access))
2686         disqualify_candidate (var,
2687                               "No or inhibitingly overlapping accesses.");
2688     }
2689
2690   propagate_all_subaccesses ();
2691
2692   bitmap_copy (tmp, candidate_bitmap);
2693   EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2694     {
2695       tree var = candidate (i);
2696       struct access *access = get_first_repr_for_decl (var);
2697
2698       if (analyze_access_trees (access))
2699         {
2700           res++;
2701           if (dump_file && (dump_flags & TDF_DETAILS))
2702             {
2703               fprintf (dump_file, "\nAccess trees for ");
2704               print_generic_expr (dump_file, var, 0);
2705               fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2706               dump_access_tree (dump_file, access);
2707               fprintf (dump_file, "\n");
2708             }
2709         }
2710       else
2711         disqualify_candidate (var, "No scalar replacements to be created.");
2712     }
2713
2714   BITMAP_FREE (tmp);
2715
2716   if (res)
2717     {
2718       statistics_counter_event (cfun, "Scalarized aggregates", res);
2719       return true;
2720     }
2721   else
2722     return false;
2723 }
2724
2725 /* Generate statements copying scalar replacements of accesses within a subtree
2726    into or out of AGG.  ACCESS, all its children, siblings and their children
2727    are to be processed.  AGG is an aggregate type expression (can be a
2728    declaration but does not have to be, it can for example also be a mem_ref or
2729    a series of handled components).  TOP_OFFSET is the offset of the processed
2730    subtree which has to be subtracted from offsets of individual accesses to
2731    get corresponding offsets for AGG.  If CHUNK_SIZE is non-null, copy only
2732    replacements in the interval <start_offset, start_offset + chunk_size>,
2733    otherwise copy all.  GSI is a statement iterator used to place the new
2734    statements.  WRITE should be true when the statements should write from AGG
2735    to the replacement and false if vice versa.  if INSERT_AFTER is true, new
2736    statements will be added after the current statement in GSI, they will be
2737    added before the statement otherwise.  */
2738
2739 static void
2740 generate_subtree_copies (struct access *access, tree agg,
2741                          HOST_WIDE_INT top_offset,
2742                          HOST_WIDE_INT start_offset, HOST_WIDE_INT chunk_size,
2743                          gimple_stmt_iterator *gsi, bool write,
2744                          bool insert_after, location_t loc)
2745 {
2746   do
2747     {
2748       if (chunk_size && access->offset >= start_offset + chunk_size)
2749         return;
2750
2751       if (access->grp_to_be_replaced
2752           && (chunk_size == 0
2753               || access->offset + access->size > start_offset))
2754         {
2755           tree expr, repl = get_access_replacement (access);
2756           gassign *stmt;
2757
2758           expr = build_ref_for_model (loc, agg, access->offset - top_offset,
2759                                       access, gsi, insert_after);
2760
2761           if (write)
2762             {
2763               if (access->grp_partial_lhs)
2764                 expr = force_gimple_operand_gsi (gsi, expr, true, NULL_TREE,
2765                                                  !insert_after,
2766                                                  insert_after ? GSI_NEW_STMT
2767                                                  : GSI_SAME_STMT);
2768               stmt = gimple_build_assign (repl, expr);
2769             }
2770           else
2771             {
2772               TREE_NO_WARNING (repl) = 1;
2773               if (access->grp_partial_lhs)
2774                 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
2775                                                  !insert_after,
2776                                                  insert_after ? GSI_NEW_STMT
2777                                                  : GSI_SAME_STMT);
2778               stmt = gimple_build_assign (expr, repl);
2779             }
2780           gimple_set_location (stmt, loc);
2781
2782           if (insert_after)
2783             gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2784           else
2785             gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2786           update_stmt (stmt);
2787           sra_stats.subtree_copies++;
2788         }
2789       else if (write
2790                && access->grp_to_be_debug_replaced
2791                && (chunk_size == 0
2792                    || access->offset + access->size > start_offset))
2793         {
2794           gdebug *ds;
2795           tree drhs = build_debug_ref_for_model (loc, agg,
2796                                                  access->offset - top_offset,
2797                                                  access);
2798           ds = gimple_build_debug_bind (get_access_replacement (access),
2799                                         drhs, gsi_stmt (*gsi));
2800           if (insert_after)
2801             gsi_insert_after (gsi, ds, GSI_NEW_STMT);
2802           else
2803             gsi_insert_before (gsi, ds, GSI_SAME_STMT);
2804         }
2805
2806       if (access->first_child)
2807         generate_subtree_copies (access->first_child, agg, top_offset,
2808                                  start_offset, chunk_size, gsi,
2809                                  write, insert_after, loc);
2810
2811       access = access->next_sibling;
2812     }
2813   while (access);
2814 }
2815
2816 /* Assign zero to all scalar replacements in an access subtree.  ACCESS is the
2817    root of the subtree to be processed.  GSI is the statement iterator used
2818    for inserting statements which are added after the current statement if
2819    INSERT_AFTER is true or before it otherwise.  */
2820
2821 static void
2822 init_subtree_with_zero (struct access *access, gimple_stmt_iterator *gsi,
2823                         bool insert_after, location_t loc)
2824
2825 {
2826   struct access *child;
2827
2828   if (access->grp_to_be_replaced)
2829     {
2830       gassign *stmt;
2831
2832       stmt = gimple_build_assign (get_access_replacement (access),
2833                                   build_zero_cst (access->type));
2834       if (insert_after)
2835         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2836       else
2837         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2838       update_stmt (stmt);
2839       gimple_set_location (stmt, loc);
2840     }
2841   else if (access->grp_to_be_debug_replaced)
2842     {
2843       gdebug *ds
2844         = gimple_build_debug_bind (get_access_replacement (access),
2845                                    build_zero_cst (access->type),
2846                                    gsi_stmt (*gsi));
2847       if (insert_after)
2848         gsi_insert_after (gsi, ds, GSI_NEW_STMT);
2849       else
2850         gsi_insert_before (gsi, ds, GSI_SAME_STMT);
2851     }
2852
2853   for (child = access->first_child; child; child = child->next_sibling)
2854     init_subtree_with_zero (child, gsi, insert_after, loc);
2855 }
2856
2857 /* Clobber all scalar replacements in an access subtree.  ACCESS is the
2858    root of the subtree to be processed.  GSI is the statement iterator used
2859    for inserting statements which are added after the current statement if
2860    INSERT_AFTER is true or before it otherwise.  */
2861
2862 static void
2863 clobber_subtree (struct access *access, gimple_stmt_iterator *gsi,
2864                 bool insert_after, location_t loc)
2865
2866 {
2867   struct access *child;
2868
2869   if (access->grp_to_be_replaced)
2870     {
2871       tree rep = get_access_replacement (access);
2872       tree clobber = build_constructor (access->type, NULL);
2873       TREE_THIS_VOLATILE (clobber) = 1;
2874       gimple *stmt = gimple_build_assign (rep, clobber);
2875
2876       if (insert_after)
2877         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2878       else
2879         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2880       update_stmt (stmt);
2881       gimple_set_location (stmt, loc);
2882     }
2883
2884   for (child = access->first_child; child; child = child->next_sibling)
2885     clobber_subtree (child, gsi, insert_after, loc);
2886 }
2887
2888 /* Search for an access representative for the given expression EXPR and
2889    return it or NULL if it cannot be found.  */
2890
2891 static struct access *
2892 get_access_for_expr (tree expr)
2893 {
2894   HOST_WIDE_INT offset, size, max_size;
2895   tree base;
2896   bool reverse;
2897
2898   /* FIXME: This should not be necessary but Ada produces V_C_Es with a type of
2899      a different size than the size of its argument and we need the latter
2900      one.  */
2901   if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
2902     expr = TREE_OPERAND (expr, 0);
2903
2904   base = get_ref_base_and_extent (expr, &offset, &size, &max_size, &reverse);
2905   if (max_size == -1 || !DECL_P (base))
2906     return NULL;
2907
2908   if (!bitmap_bit_p (candidate_bitmap, DECL_UID (base)))
2909     return NULL;
2910
2911   return get_var_base_offset_size_access (base, offset, max_size);
2912 }
2913
2914 /* Replace the expression EXPR with a scalar replacement if there is one and
2915    generate other statements to do type conversion or subtree copying if
2916    necessary.  GSI is used to place newly created statements, WRITE is true if
2917    the expression is being written to (it is on a LHS of a statement or output
2918    in an assembly statement).  */
2919
2920 static bool
2921 sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi, bool write)
2922 {
2923   location_t loc;
2924   struct access *access;
2925   tree type, bfr, orig_expr;
2926
2927   if (TREE_CODE (*expr) == BIT_FIELD_REF)
2928     {
2929       bfr = *expr;
2930       expr = &TREE_OPERAND (*expr, 0);
2931     }
2932   else
2933     bfr = NULL_TREE;
2934
2935   if (TREE_CODE (*expr) == REALPART_EXPR || TREE_CODE (*expr) == IMAGPART_EXPR)
2936     expr = &TREE_OPERAND (*expr, 0);
2937   access = get_access_for_expr (*expr);
2938   if (!access)
2939     return false;
2940   type = TREE_TYPE (*expr);
2941   orig_expr = *expr;
2942
2943   loc = gimple_location (gsi_stmt (*gsi));
2944   gimple_stmt_iterator alt_gsi = gsi_none ();
2945   if (write && stmt_ends_bb_p (gsi_stmt (*gsi)))
2946     {
2947       alt_gsi = gsi_start_edge (single_non_eh_succ (gsi_bb (*gsi)));
2948       gsi = &alt_gsi;
2949     }
2950
2951   if (access->grp_to_be_replaced)
2952     {
2953       tree repl = get_access_replacement (access);
2954       /* If we replace a non-register typed access simply use the original
2955          access expression to extract the scalar component afterwards.
2956          This happens if scalarizing a function return value or parameter
2957          like in gcc.c-torture/execute/20041124-1.c, 20050316-1.c and
2958          gcc.c-torture/compile/20011217-1.c.
2959
2960          We also want to use this when accessing a complex or vector which can
2961          be accessed as a different type too, potentially creating a need for
2962          type conversion (see PR42196) and when scalarized unions are involved
2963          in assembler statements (see PR42398).  */
2964       if (!useless_type_conversion_p (type, access->type))
2965         {
2966           tree ref;
2967
2968           ref = build_ref_for_model (loc, orig_expr, 0, access, gsi, false);
2969
2970           if (write)
2971             {
2972               gassign *stmt;
2973
2974               if (access->grp_partial_lhs)
2975                 ref = force_gimple_operand_gsi (gsi, ref, true, NULL_TREE,
2976                                                  false, GSI_NEW_STMT);
2977               stmt = gimple_build_assign (repl, ref);
2978               gimple_set_location (stmt, loc);
2979               gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2980             }
2981           else
2982             {
2983               gassign *stmt;
2984
2985               if (access->grp_partial_lhs)
2986                 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
2987                                                  true, GSI_SAME_STMT);
2988               stmt = gimple_build_assign (ref, repl);
2989               gimple_set_location (stmt, loc);
2990               gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2991             }
2992         }
2993       else
2994         *expr = repl;
2995       sra_stats.exprs++;
2996     }
2997   else if (write && access->grp_to_be_debug_replaced)
2998     {
2999       gdebug *ds = gimple_build_debug_bind (get_access_replacement (access),
3000                                             NULL_TREE,
3001                                             gsi_stmt (*gsi));
3002       gsi_insert_after (gsi, ds, GSI_NEW_STMT);
3003     }
3004
3005   if (access->first_child)
3006     {
3007       HOST_WIDE_INT start_offset, chunk_size;
3008       if (bfr
3009           && tree_fits_uhwi_p (TREE_OPERAND (bfr, 1))
3010           && tree_fits_uhwi_p (TREE_OPERAND (bfr, 2)))
3011         {
3012           chunk_size = tree_to_uhwi (TREE_OPERAND (bfr, 1));
3013           start_offset = access->offset
3014             + tree_to_uhwi (TREE_OPERAND (bfr, 2));
3015         }
3016       else
3017         start_offset = chunk_size = 0;
3018
3019       generate_subtree_copies (access->first_child, orig_expr, access->offset,
3020                                start_offset, chunk_size, gsi, write, write,
3021                                loc);
3022     }
3023   return true;
3024 }
3025
3026 /* Where scalar replacements of the RHS have been written to when a replacement
3027    of a LHS of an assigments cannot be direclty loaded from a replacement of
3028    the RHS. */
3029 enum unscalarized_data_handling { SRA_UDH_NONE,  /* Nothing done so far. */
3030                                   SRA_UDH_RIGHT, /* Data flushed to the RHS. */
3031                                   SRA_UDH_LEFT }; /* Data flushed to the LHS. */
3032
3033 struct subreplacement_assignment_data
3034 {
3035   /* Offset of the access representing the lhs of the assignment.  */
3036   HOST_WIDE_INT left_offset;
3037
3038   /* LHS and RHS of the original assignment.  */
3039   tree assignment_lhs, assignment_rhs;
3040
3041   /* Access representing the rhs of the whole assignment.  */
3042   struct access *top_racc;
3043
3044   /* Stmt iterator used for statement insertions after the original assignment.
3045    It points to the main GSI used to traverse a BB during function body
3046    modification.  */
3047   gimple_stmt_iterator *new_gsi;
3048
3049   /* Stmt iterator used for statement insertions before the original
3050    assignment.  Keeps on pointing to the original statement.  */
3051   gimple_stmt_iterator old_gsi;
3052
3053   /* Location of the assignment.   */
3054   location_t loc;
3055
3056   /* Keeps the information whether we have needed to refresh replacements of
3057    the LHS and from which side of the assignments this takes place.  */
3058   enum unscalarized_data_handling refreshed;
3059 };
3060
3061 /* Store all replacements in the access tree rooted in TOP_RACC either to their
3062    base aggregate if there are unscalarized data or directly to LHS of the
3063    statement that is pointed to by GSI otherwise.  */
3064
3065 static void
3066 handle_unscalarized_data_in_subtree (struct subreplacement_assignment_data *sad)
3067 {
3068   tree src;
3069   if (sad->top_racc->grp_unscalarized_data)
3070     {
3071       src = sad->assignment_rhs;
3072       sad->refreshed = SRA_UDH_RIGHT;
3073     }
3074   else
3075     {
3076       src = sad->assignment_lhs;
3077       sad->refreshed = SRA_UDH_LEFT;
3078     }
3079   generate_subtree_copies (sad->top_racc->first_child, src,
3080                            sad->top_racc->offset, 0, 0,
3081                            &sad->old_gsi, false, false, sad->loc);
3082 }
3083
3084 /* Try to generate statements to load all sub-replacements in an access subtree
3085    formed by children of LACC from scalar replacements in the SAD->top_racc
3086    subtree.  If that is not possible, refresh the SAD->top_racc base aggregate
3087    and load the accesses from it.  */
3088
3089 static void
3090 load_assign_lhs_subreplacements (struct access *lacc,
3091                                  struct subreplacement_assignment_data *sad)
3092 {
3093   for (lacc = lacc->first_child; lacc; lacc = lacc->next_sibling)
3094     {
3095       HOST_WIDE_INT offset;
3096       offset = lacc->offset - sad->left_offset + sad->top_racc->offset;
3097
3098       if (lacc->grp_to_be_replaced)
3099         {
3100           struct access *racc;
3101           gassign *stmt;
3102           tree rhs;
3103
3104           racc = find_access_in_subtree (sad->top_racc, offset, lacc->size);
3105           if (racc && racc->grp_to_be_replaced)
3106             {
3107               rhs = get_access_replacement (racc);
3108               if (!useless_type_conversion_p (lacc->type, racc->type))
3109                 rhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
3110                                        lacc->type, rhs);
3111
3112               if (racc->grp_partial_lhs && lacc->grp_partial_lhs)
3113                 rhs = force_gimple_operand_gsi (&sad->old_gsi, rhs, true,
3114                                                 NULL_TREE, true, GSI_SAME_STMT);
3115             }
3116           else
3117             {
3118               /* No suitable access on the right hand side, need to load from
3119                  the aggregate.  See if we have to update it first... */
3120               if (sad->refreshed == SRA_UDH_NONE)
3121                 handle_unscalarized_data_in_subtree (sad);
3122
3123               if (sad->refreshed == SRA_UDH_LEFT)
3124                 rhs = build_ref_for_model (sad->loc, sad->assignment_lhs,
3125                                            lacc->offset - sad->left_offset,
3126                                            lacc, sad->new_gsi, true);
3127               else
3128                 rhs = build_ref_for_model (sad->loc, sad->assignment_rhs,
3129                                            lacc->offset - sad->left_offset,
3130                                            lacc, sad->new_gsi, true);
3131               if (lacc->grp_partial_lhs)
3132                 rhs = force_gimple_operand_gsi (sad->new_gsi,
3133                                                 rhs, true, NULL_TREE,
3134                                                 false, GSI_NEW_STMT);
3135             }
3136
3137           stmt = gimple_build_assign (get_access_replacement (lacc), rhs);
3138           gsi_insert_after (sad->new_gsi, stmt, GSI_NEW_STMT);
3139           gimple_set_location (stmt, sad->loc);
3140           update_stmt (stmt);
3141           sra_stats.subreplacements++;
3142         }
3143       else
3144         {
3145           if (sad->refreshed == SRA_UDH_NONE
3146               && lacc->grp_read && !lacc->grp_covered)
3147             handle_unscalarized_data_in_subtree (sad);
3148
3149           if (lacc && lacc->grp_to_be_debug_replaced)
3150             {
3151               gdebug *ds;
3152               tree drhs;
3153               struct access *racc = find_access_in_subtree (sad->top_racc,
3154                                                             offset,
3155                                                             lacc->size);
3156
3157               if (racc && racc->grp_to_be_replaced)
3158                 {
3159                   if (racc->grp_write || constant_decl_p (racc->base))
3160                     drhs = get_access_replacement (racc);
3161                   else
3162                     drhs = NULL;
3163                 }
3164               else if (sad->refreshed == SRA_UDH_LEFT)
3165                 drhs = build_debug_ref_for_model (sad->loc, lacc->base,
3166                                                   lacc->offset, lacc);
3167               else if (sad->refreshed == SRA_UDH_RIGHT)
3168                 drhs = build_debug_ref_for_model (sad->loc, sad->top_racc->base,
3169                                                   offset, lacc);
3170               else
3171                 drhs = NULL_TREE;
3172               if (drhs
3173                   && !useless_type_conversion_p (lacc->type, TREE_TYPE (drhs)))
3174                 drhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
3175                                         lacc->type, drhs);
3176               ds = gimple_build_debug_bind (get_access_replacement (lacc),
3177                                             drhs, gsi_stmt (sad->old_gsi));
3178               gsi_insert_after (sad->new_gsi, ds, GSI_NEW_STMT);
3179             }
3180         }
3181
3182       if (lacc->first_child)
3183         load_assign_lhs_subreplacements (lacc, sad);
3184     }
3185 }
3186
3187 /* Result code for SRA assignment modification.  */
3188 enum assignment_mod_result { SRA_AM_NONE,       /* nothing done for the stmt */
3189                              SRA_AM_MODIFIED,  /* stmt changed but not
3190                                                   removed */
3191                              SRA_AM_REMOVED };  /* stmt eliminated */
3192
3193 /* Modify assignments with a CONSTRUCTOR on their RHS.  STMT contains a pointer
3194    to the assignment and GSI is the statement iterator pointing at it.  Returns
3195    the same values as sra_modify_assign.  */
3196
3197 static enum assignment_mod_result
3198 sra_modify_constructor_assign (gimple *stmt, gimple_stmt_iterator *gsi)
3199 {
3200   tree lhs = gimple_assign_lhs (stmt);
3201   struct access *acc = get_access_for_expr (lhs);
3202   if (!acc)
3203     return SRA_AM_NONE;
3204   location_t loc = gimple_location (stmt);
3205
3206   if (gimple_clobber_p (stmt))
3207     {
3208       /* Clobber the replacement variable.  */
3209       clobber_subtree (acc, gsi, !acc->grp_covered, loc);
3210       /* Remove clobbers of fully scalarized variables, they are dead.  */
3211       if (acc->grp_covered)
3212         {
3213           unlink_stmt_vdef (stmt);
3214           gsi_remove (gsi, true);
3215           release_defs (stmt);
3216           return SRA_AM_REMOVED;
3217         }
3218       else
3219         return SRA_AM_MODIFIED;
3220     }
3221
3222   if (vec_safe_length (CONSTRUCTOR_ELTS (gimple_assign_rhs1 (stmt))) > 0)
3223     {
3224       /* I have never seen this code path trigger but if it can happen the
3225          following should handle it gracefully.  */
3226       if (access_has_children_p (acc))
3227         generate_subtree_copies (acc->first_child, lhs, acc->offset, 0, 0, gsi,
3228                                  true, true, loc);
3229       return SRA_AM_MODIFIED;
3230     }
3231
3232   if (acc->grp_covered)
3233     {
3234       init_subtree_with_zero (acc, gsi, false, loc);
3235       unlink_stmt_vdef (stmt);
3236       gsi_remove (gsi, true);
3237       release_defs (stmt);
3238       return SRA_AM_REMOVED;
3239     }
3240   else
3241     {
3242       init_subtree_with_zero (acc, gsi, true, loc);
3243       return SRA_AM_MODIFIED;
3244     }
3245 }
3246
3247 /* Create and return a new suitable default definition SSA_NAME for RACC which
3248    is an access describing an uninitialized part of an aggregate that is being
3249    loaded.  */
3250
3251 static tree
3252 get_repl_default_def_ssa_name (struct access *racc)
3253 {
3254   gcc_checking_assert (!racc->grp_to_be_replaced
3255                        && !racc->grp_to_be_debug_replaced);
3256   if (!racc->replacement_decl)
3257     racc->replacement_decl = create_access_replacement (racc);
3258   return get_or_create_ssa_default_def (cfun, racc->replacement_decl);
3259 }
3260
3261 /* Return true if REF has an VIEW_CONVERT_EXPR or a COMPONENT_REF with a
3262    bit-field field declaration somewhere in it.  */
3263
3264 static inline bool
3265 contains_vce_or_bfcref_p (const_tree ref)
3266 {
3267   while (handled_component_p (ref))
3268     {
3269       if (TREE_CODE (ref) == VIEW_CONVERT_EXPR
3270           || (TREE_CODE (ref) == COMPONENT_REF
3271               && DECL_BIT_FIELD (TREE_OPERAND (ref, 1))))
3272         return true;
3273       ref = TREE_OPERAND (ref, 0);
3274     }
3275
3276   return false;
3277 }
3278
3279 /* Examine both sides of the assignment statement pointed to by STMT, replace
3280    them with a scalare replacement if there is one and generate copying of
3281    replacements if scalarized aggregates have been used in the assignment.  GSI
3282    is used to hold generated statements for type conversions and subtree
3283    copying.  */
3284
3285 static enum assignment_mod_result
3286 sra_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi)
3287 {
3288   struct access *lacc, *racc;
3289   tree lhs, rhs;
3290   bool modify_this_stmt = false;
3291   bool force_gimple_rhs = false;
3292   location_t loc;
3293   gimple_stmt_iterator orig_gsi = *gsi;
3294
3295   if (!gimple_assign_single_p (stmt))
3296     return SRA_AM_NONE;
3297   lhs = gimple_assign_lhs (stmt);
3298   rhs = gimple_assign_rhs1 (stmt);
3299
3300   if (TREE_CODE (rhs) == CONSTRUCTOR)
3301     return sra_modify_constructor_assign (stmt, gsi);
3302
3303   if (TREE_CODE (rhs) == REALPART_EXPR || TREE_CODE (lhs) == REALPART_EXPR
3304       || TREE_CODE (rhs) == IMAGPART_EXPR || TREE_CODE (lhs) == IMAGPART_EXPR
3305       || TREE_CODE (rhs) == BIT_FIELD_REF || TREE_CODE (lhs) == BIT_FIELD_REF)
3306     {
3307       modify_this_stmt = sra_modify_expr (gimple_assign_rhs1_ptr (stmt),
3308                                           gsi, false);
3309       modify_this_stmt |= sra_modify_expr (gimple_assign_lhs_ptr (stmt),
3310                                            gsi, true);
3311       return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
3312     }
3313
3314   lacc = get_access_for_expr (lhs);
3315   racc = get_access_for_expr (rhs);
3316   if (!lacc && !racc)
3317     return SRA_AM_NONE;
3318   /* Avoid modifying initializations of constant-pool replacements.  */
3319   if (racc && (racc->replacement_decl == lhs))
3320     return SRA_AM_NONE;
3321
3322   loc = gimple_location (stmt);
3323   if (lacc && lacc->grp_to_be_replaced)
3324     {
3325       lhs = get_access_replacement (lacc);
3326       gimple_assign_set_lhs (stmt, lhs);
3327       modify_this_stmt = true;
3328       if (lacc->grp_partial_lhs)
3329         force_gimple_rhs = true;
3330       sra_stats.exprs++;
3331     }
3332
3333   if (racc && racc->grp_to_be_replaced)
3334     {
3335       rhs = get_access_replacement (racc);
3336       modify_this_stmt = true;
3337       if (racc->grp_partial_lhs)
3338         force_gimple_rhs = true;
3339       sra_stats.exprs++;
3340     }
3341   else if (racc
3342            && !racc->grp_unscalarized_data
3343            && !racc->grp_unscalarizable_region
3344            && TREE_CODE (lhs) == SSA_NAME
3345            && !access_has_replacements_p (racc))
3346     {
3347       rhs = get_repl_default_def_ssa_name (racc);
3348       modify_this_stmt = true;
3349       sra_stats.exprs++;
3350     }
3351
3352   if (modify_this_stmt)
3353     {
3354       if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
3355         {
3356           /* If we can avoid creating a VIEW_CONVERT_EXPR do so.
3357              ???  This should move to fold_stmt which we simply should
3358              call after building a VIEW_CONVERT_EXPR here.  */
3359           if (AGGREGATE_TYPE_P (TREE_TYPE (lhs))
3360               && !contains_bitfld_component_ref_p (lhs))
3361             {
3362               lhs = build_ref_for_model (loc, lhs, 0, racc, gsi, false);
3363               gimple_assign_set_lhs (stmt, lhs);
3364             }
3365           else if (AGGREGATE_TYPE_P (TREE_TYPE (rhs))
3366                    && !contains_vce_or_bfcref_p (rhs))
3367             rhs = build_ref_for_model (loc, rhs, 0, lacc, gsi, false);
3368
3369           if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
3370             {
3371               rhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR, TREE_TYPE (lhs),
3372                                      rhs);
3373               if (is_gimple_reg_type (TREE_TYPE (lhs))
3374                   && TREE_CODE (lhs) != SSA_NAME)
3375                 force_gimple_rhs = true;
3376             }
3377         }
3378     }
3379
3380   if (lacc && lacc->grp_to_be_debug_replaced)
3381     {
3382       tree dlhs = get_access_replacement (lacc);
3383       tree drhs = unshare_expr (rhs);
3384       if (!useless_type_conversion_p (TREE_TYPE (dlhs), TREE_TYPE (drhs)))
3385         {
3386           if (AGGREGATE_TYPE_P (TREE_TYPE (drhs))
3387               && !contains_vce_or_bfcref_p (drhs))
3388             drhs = build_debug_ref_for_model (loc, drhs, 0, lacc);
3389           if (drhs
3390               && !useless_type_conversion_p (TREE_TYPE (dlhs),
3391                                              TREE_TYPE (drhs)))
3392             drhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR,
3393                                     TREE_TYPE (dlhs), drhs);
3394         }
3395       gdebug *ds = gimple_build_debug_bind (dlhs, drhs, stmt);
3396       gsi_insert_before (gsi, ds, GSI_SAME_STMT);
3397     }
3398
3399   /* From this point on, the function deals with assignments in between
3400      aggregates when at least one has scalar reductions of some of its
3401      components.  There are three possible scenarios: Both the LHS and RHS have
3402      to-be-scalarized components, 2) only the RHS has or 3) only the LHS has.
3403
3404      In the first case, we would like to load the LHS components from RHS
3405      components whenever possible.  If that is not possible, we would like to
3406      read it directly from the RHS (after updating it by storing in it its own
3407      components).  If there are some necessary unscalarized data in the LHS,
3408      those will be loaded by the original assignment too.  If neither of these
3409      cases happen, the original statement can be removed.  Most of this is done
3410      by load_assign_lhs_subreplacements.
3411
3412      In the second case, we would like to store all RHS scalarized components
3413      directly into LHS and if they cover the aggregate completely, remove the
3414      statement too.  In the third case, we want the LHS components to be loaded
3415      directly from the RHS (DSE will remove the original statement if it
3416      becomes redundant).
3417
3418      This is a bit complex but manageable when types match and when unions do
3419      not cause confusion in a way that we cannot really load a component of LHS
3420      from the RHS or vice versa (the access representing this level can have
3421      subaccesses that are accessible only through a different union field at a
3422      higher level - different from the one used in the examined expression).
3423      Unions are fun.
3424
3425      Therefore, I specially handle a fourth case, happening when there is a
3426      specific type cast or it is impossible to locate a scalarized subaccess on
3427      the other side of the expression.  If that happens, I simply "refresh" the
3428      RHS by storing in it is scalarized components leave the original statement
3429      there to do the copying and then load the scalar replacements of the LHS.
3430      This is what the first branch does.  */
3431
3432   if (modify_this_stmt
3433       || gimple_has_volatile_ops (stmt)
3434       || contains_vce_or_bfcref_p (rhs)
3435       || contains_vce_or_bfcref_p (lhs)
3436       || stmt_ends_bb_p (stmt))
3437     {
3438       /* No need to copy into a constant-pool, it comes pre-initialized.  */
3439       if (access_has_children_p (racc) && !constant_decl_p (racc->base))
3440         generate_subtree_copies (racc->first_child, rhs, racc->offset, 0, 0,
3441                                  gsi, false, false, loc);
3442       if (access_has_children_p (lacc))
3443         {
3444           gimple_stmt_iterator alt_gsi = gsi_none ();
3445           if (stmt_ends_bb_p (stmt))
3446             {
3447               alt_gsi = gsi_start_edge (single_non_eh_succ (gsi_bb (*gsi)));
3448               gsi = &alt_gsi;
3449             }
3450           generate_subtree_copies (lacc->first_child, lhs, lacc->offset, 0, 0,
3451                                    gsi, true, true, loc);
3452         }
3453       sra_stats.separate_lhs_rhs_handling++;
3454
3455       /* This gimplification must be done after generate_subtree_copies,
3456          lest we insert the subtree copies in the middle of the gimplified
3457          sequence.  */
3458       if (force_gimple_rhs)
3459         rhs = force_gimple_operand_gsi (&orig_gsi, rhs, true, NULL_TREE,
3460                                         true, GSI_SAME_STMT);
3461       if (gimple_assign_rhs1 (stmt) != rhs)
3462         {
3463           modify_this_stmt = true;
3464           gimple_assign_set_rhs_from_tree (&orig_gsi, rhs);
3465           gcc_assert (stmt == gsi_stmt (orig_gsi));
3466         }
3467
3468       return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
3469     }
3470   else
3471     {
3472       if (access_has_children_p (lacc)
3473           && access_has_children_p (racc)
3474           /* When an access represents an unscalarizable region, it usually
3475              represents accesses with variable offset and thus must not be used
3476              to generate new memory accesses.  */
3477           && !lacc->grp_unscalarizable_region
3478           && !racc->grp_unscalarizable_region)
3479         {
3480           struct subreplacement_assignment_data sad;
3481
3482           sad.left_offset = lacc->offset;
3483           sad.assignment_lhs = lhs;
3484           sad.assignment_rhs = rhs;
3485           sad.top_racc = racc;
3486           sad.old_gsi = *gsi;
3487           sad.new_gsi = gsi;
3488           sad.loc = gimple_location (stmt);
3489           sad.refreshed = SRA_UDH_NONE;
3490
3491           if (lacc->grp_read && !lacc->grp_covered)
3492             handle_unscalarized_data_in_subtree (&sad);
3493
3494           load_assign_lhs_subreplacements (lacc, &sad);
3495           if (sad.refreshed != SRA_UDH_RIGHT)
3496             {
3497               gsi_next (gsi);
3498               unlink_stmt_vdef (stmt);
3499               gsi_remove (&sad.old_gsi, true);
3500               release_defs (stmt);
3501               sra_stats.deleted++;
3502               return SRA_AM_REMOVED;
3503             }
3504         }
3505       else
3506         {
3507           if (access_has_children_p (racc)
3508               && !racc->grp_unscalarized_data
3509               && TREE_CODE (lhs) != SSA_NAME)
3510             {
3511               if (dump_file)
3512                 {
3513                   fprintf (dump_file, "Removing load: ");
3514                   print_gimple_stmt (dump_file, stmt, 0, 0);
3515                 }
3516               generate_subtree_copies (racc->first_child, lhs,
3517                                        racc->offset, 0, 0, gsi,
3518                                        false, false, loc);
3519               gcc_assert (stmt == gsi_stmt (*gsi));
3520               unlink_stmt_vdef (stmt);
3521               gsi_remove (gsi, true);
3522               release_defs (stmt);
3523               sra_stats.deleted++;
3524               return SRA_AM_REMOVED;
3525             }
3526           /* Restore the aggregate RHS from its components so the
3527              prevailing aggregate copy does the right thing.  */
3528           if (access_has_children_p (racc))
3529             generate_subtree_copies (racc->first_child, rhs, racc->offset, 0, 0,
3530                                      gsi, false, false, loc);
3531           /* Re-load the components of the aggregate copy destination.
3532              But use the RHS aggregate to load from to expose more
3533              optimization opportunities.  */
3534           if (access_has_children_p (lacc))
3535             generate_subtree_copies (lacc->first_child, rhs, lacc->offset,
3536                                      0, 0, gsi, true, true, loc);
3537         }
3538
3539       return SRA_AM_NONE;
3540     }
3541 }
3542
3543 /* Set any scalar replacements of values in the constant pool to the initial
3544    value of the constant.  (Constant-pool decls like *.LC0 have effectively
3545    been initialized before the program starts, we must do the same for their
3546    replacements.)  Thus, we output statements like 'SR.1 = *.LC0[0];' into
3547    the function's entry block.  */
3548
3549 static void
3550 initialize_constant_pool_replacements (void)
3551 {
3552   gimple_seq seq = NULL;
3553   gimple_stmt_iterator gsi = gsi_start (seq);
3554   bitmap_iterator bi;
3555   unsigned i;
3556
3557   EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
3558     if (bitmap_bit_p (should_scalarize_away_bitmap, i)
3559         && !bitmap_bit_p (cannot_scalarize_away_bitmap, i))
3560       {
3561         tree var = candidate (i);
3562         if (!constant_decl_p (var))
3563           continue;
3564         vec<access_p> *access_vec = get_base_access_vector (var);
3565         if (!access_vec)
3566           continue;
3567         for (unsigned i = 0; i < access_vec->length (); i++)
3568           {
3569             struct access *access = (*access_vec)[i];
3570             if (!access->replacement_decl)
3571               continue;
3572             gassign *stmt = gimple_build_assign (
3573               get_access_replacement (access), unshare_expr (access->expr));
3574             if (dump_file && (dump_flags & TDF_DETAILS))
3575               {
3576                 fprintf (dump_file, "Generating constant initializer: ");
3577                 print_gimple_stmt (dump_file, stmt, 0, 1);
3578                 fprintf (dump_file, "\n");
3579               }
3580             gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
3581             update_stmt (stmt);
3582           }
3583       }
3584
3585   seq = gsi_seq (gsi);
3586   if (seq)
3587     gsi_insert_seq_on_edge_immediate (
3588       single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)), seq);
3589 }
3590
3591 /* Traverse the function body and all modifications as decided in
3592    analyze_all_variable_accesses.  Return true iff the CFG has been
3593    changed.  */
3594
3595 static bool
3596 sra_modify_function_body (void)
3597 {
3598   bool cfg_changed = false;
3599   basic_block bb;
3600
3601   initialize_constant_pool_replacements ();
3602
3603   FOR_EACH_BB_FN (bb, cfun)
3604     {
3605       gimple_stmt_iterator gsi = gsi_start_bb (bb);
3606       while (!gsi_end_p (gsi))
3607         {
3608           gimple *stmt = gsi_stmt (gsi);
3609           enum assignment_mod_result assign_result;
3610           bool modified = false, deleted = false;
3611           tree *t;
3612           unsigned i;
3613
3614           switch (gimple_code (stmt))
3615             {
3616             case GIMPLE_RETURN:
3617               t = gimple_return_retval_ptr (as_a <greturn *> (stmt));
3618               if (*t != NULL_TREE)
3619                 modified |= sra_modify_expr (t, &gsi, false);
3620               break;
3621
3622             case GIMPLE_ASSIGN:
3623               assign_result = sra_modify_assign (stmt, &gsi);
3624               modified |= assign_result == SRA_AM_MODIFIED;
3625               deleted = assign_result == SRA_AM_REMOVED;
3626               break;
3627
3628             case GIMPLE_CALL:
3629               /* Operands must be processed before the lhs.  */
3630               for (i = 0; i < gimple_call_num_args (stmt); i++)
3631                 {
3632                   t = gimple_call_arg_ptr (stmt, i);
3633                   modified |= sra_modify_expr (t, &gsi, false);
3634                 }
3635
3636               if (gimple_call_lhs (stmt))
3637                 {
3638                   t = gimple_call_lhs_ptr (stmt);
3639                   modified |= sra_modify_expr (t, &gsi, true);
3640                 }
3641               break;
3642
3643             case GIMPLE_ASM:
3644               {
3645                 gasm *asm_stmt = as_a <gasm *> (stmt);
3646                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
3647                   {
3648                     t = &TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
3649                     modified |= sra_modify_expr (t, &gsi, false);
3650                   }
3651                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
3652                   {
3653                     t = &TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
3654                     modified |= sra_modify_expr (t, &gsi, true);
3655                   }
3656               }
3657               break;
3658
3659             default:
3660               break;
3661             }
3662
3663           if (modified)
3664             {
3665               update_stmt (stmt);
3666               if (maybe_clean_eh_stmt (stmt)
3667                   && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
3668                 cfg_changed = true;
3669             }
3670           if (!deleted)
3671             gsi_next (&gsi);
3672         }
3673     }
3674
3675   gsi_commit_edge_inserts ();
3676   return cfg_changed;
3677 }
3678
3679 /* Generate statements initializing scalar replacements of parts of function
3680    parameters.  */
3681
3682 static void
3683 initialize_parameter_reductions (void)
3684 {
3685   gimple_stmt_iterator gsi;
3686   gimple_seq seq = NULL;
3687   tree parm;
3688
3689   gsi = gsi_start (seq);
3690   for (parm = DECL_ARGUMENTS (current_function_decl);
3691        parm;
3692        parm = DECL_CHAIN (parm))
3693     {
3694       vec<access_p> *access_vec;
3695       struct access *access;
3696
3697       if (!bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
3698         continue;
3699       access_vec = get_base_access_vector (parm);
3700       if (!access_vec)
3701         continue;
3702
3703       for (access = (*access_vec)[0];
3704            access;
3705            access = access->next_grp)
3706         generate_subtree_copies (access, parm, 0, 0, 0, &gsi, true, true,
3707                                  EXPR_LOCATION (parm));
3708     }
3709
3710   seq = gsi_seq (gsi);
3711   if (seq)
3712     gsi_insert_seq_on_edge_immediate (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)), seq);
3713 }
3714
3715 /* The "main" function of intraprocedural SRA passes.  Runs the analysis and if
3716    it reveals there are components of some aggregates to be scalarized, it runs
3717    the required transformations.  */
3718 static unsigned int
3719 perform_intra_sra (void)
3720 {
3721   int ret = 0;
3722   sra_initialize ();
3723
3724   if (!find_var_candidates ())
3725     goto out;
3726
3727   if (!scan_function ())
3728     goto out;
3729
3730   if (!analyze_all_variable_accesses ())
3731     goto out;
3732
3733   if (sra_modify_function_body ())
3734     ret = TODO_update_ssa | TODO_cleanup_cfg;
3735   else
3736     ret = TODO_update_ssa;
3737   initialize_parameter_reductions ();
3738
3739   statistics_counter_event (cfun, "Scalar replacements created",
3740                             sra_stats.replacements);
3741   statistics_counter_event (cfun, "Modified expressions", sra_stats.exprs);
3742   statistics_counter_event (cfun, "Subtree copy stmts",
3743                             sra_stats.subtree_copies);
3744   statistics_counter_event (cfun, "Subreplacement stmts",
3745                             sra_stats.subreplacements);
3746   statistics_counter_event (cfun, "Deleted stmts", sra_stats.deleted);
3747   statistics_counter_event (cfun, "Separate LHS and RHS handling",
3748                             sra_stats.separate_lhs_rhs_handling);
3749
3750  out:
3751   sra_deinitialize ();
3752   return ret;
3753 }
3754
3755 /* Perform early intraprocedural SRA.  */
3756 static unsigned int
3757 early_intra_sra (void)
3758 {
3759   sra_mode = SRA_MODE_EARLY_INTRA;
3760   return perform_intra_sra ();
3761 }
3762
3763 /* Perform "late" intraprocedural SRA.  */
3764 static unsigned int
3765 late_intra_sra (void)
3766 {
3767   sra_mode = SRA_MODE_INTRA;
3768   return perform_intra_sra ();
3769 }
3770
3771
3772 static bool
3773 gate_intra_sra (void)
3774 {
3775   return flag_tree_sra != 0 && dbg_cnt (tree_sra);
3776 }
3777
3778
3779 namespace {
3780
3781 const pass_data pass_data_sra_early =
3782 {
3783   GIMPLE_PASS, /* type */
3784   "esra", /* name */
3785   OPTGROUP_NONE, /* optinfo_flags */
3786   TV_TREE_SRA, /* tv_id */
3787   ( PROP_cfg | PROP_ssa ), /* properties_required */
3788   0, /* properties_provided */
3789   0, /* properties_destroyed */
3790   0, /* todo_flags_start */
3791   TODO_update_ssa, /* todo_flags_finish */
3792 };
3793
3794 class pass_sra_early : public gimple_opt_pass
3795 {
3796 public:
3797   pass_sra_early (gcc::context *ctxt)
3798     : gimple_opt_pass (pass_data_sra_early, ctxt)
3799   {}
3800
3801   /* opt_pass methods: */
3802   virtual bool gate (function *) { return gate_intra_sra (); }
3803   virtual unsigned int execute (function *) { return early_intra_sra (); }
3804
3805 }; // class pass_sra_early
3806
3807 } // anon namespace
3808
3809 gimple_opt_pass *
3810 make_pass_sra_early (gcc::context *ctxt)
3811 {
3812   return new pass_sra_early (ctxt);
3813 }
3814
3815 namespace {
3816
3817 const pass_data pass_data_sra =
3818 {
3819   GIMPLE_PASS, /* type */
3820   "sra", /* name */
3821   OPTGROUP_NONE, /* optinfo_flags */
3822   TV_TREE_SRA, /* tv_id */
3823   ( PROP_cfg | PROP_ssa ), /* properties_required */
3824   0, /* properties_provided */
3825   0, /* properties_destroyed */
3826   TODO_update_address_taken, /* todo_flags_start */
3827   TODO_update_ssa, /* todo_flags_finish */
3828 };
3829
3830 class pass_sra : public gimple_opt_pass
3831 {
3832 public:
3833   pass_sra (gcc::context *ctxt)
3834     : gimple_opt_pass (pass_data_sra, ctxt)
3835   {}
3836
3837   /* opt_pass methods: */
3838   virtual bool gate (function *) { return gate_intra_sra (); }
3839   virtual unsigned int execute (function *) { return late_intra_sra (); }
3840
3841 }; // class pass_sra
3842
3843 } // anon namespace
3844
3845 gimple_opt_pass *
3846 make_pass_sra (gcc::context *ctxt)
3847 {
3848   return new pass_sra (ctxt);
3849 }
3850
3851
3852 /* Return true iff PARM (which must be a parm_decl) is an unused scalar
3853    parameter.  */
3854
3855 static bool
3856 is_unused_scalar_param (tree parm)
3857 {
3858   tree name;
3859   return (is_gimple_reg (parm)
3860           && (!(name = ssa_default_def (cfun, parm))
3861               || has_zero_uses (name)));
3862 }
3863
3864 /* Scan immediate uses of a default definition SSA name of a parameter PARM and
3865    examine whether there are any direct or otherwise infeasible ones.  If so,
3866    return true, otherwise return false.  PARM must be a gimple register with a
3867    non-NULL default definition.  */
3868
3869 static bool
3870 ptr_parm_has_direct_uses (tree parm)
3871 {
3872   imm_use_iterator ui;
3873   gimple *stmt;
3874   tree name = ssa_default_def (cfun, parm);
3875   bool ret = false;
3876
3877   FOR_EACH_IMM_USE_STMT (stmt, ui, name)
3878     {
3879       int uses_ok = 0;
3880       use_operand_p use_p;
3881
3882       if (is_gimple_debug (stmt))
3883         continue;
3884
3885       /* Valid uses include dereferences on the lhs and the rhs.  */
3886       if (gimple_has_lhs (stmt))
3887         {
3888           tree lhs = gimple_get_lhs (stmt);
3889           while (handled_component_p (lhs))
3890             lhs = TREE_OPERAND (lhs, 0);
3891           if (TREE_CODE (lhs) == MEM_REF
3892               && TREE_OPERAND (lhs, 0) == name
3893               && integer_zerop (TREE_OPERAND (lhs, 1))
3894               && types_compatible_p (TREE_TYPE (lhs),
3895                                      TREE_TYPE (TREE_TYPE (name)))
3896               && !TREE_THIS_VOLATILE (lhs))
3897             uses_ok++;
3898         }
3899       if (gimple_assign_single_p (stmt))
3900         {
3901           tree rhs = gimple_assign_rhs1 (stmt);
3902           while (handled_component_p (rhs))
3903             rhs = TREE_OPERAND (rhs, 0);
3904           if (TREE_CODE (rhs) == MEM_REF
3905               && TREE_OPERAND (rhs, 0) == name
3906               && integer_zerop (TREE_OPERAND (rhs, 1))
3907               && types_compatible_p (TREE_TYPE (rhs),
3908                                      TREE_TYPE (TREE_TYPE (name)))
3909               && !TREE_THIS_VOLATILE (rhs))
3910             uses_ok++;
3911         }
3912       else if (is_gimple_call (stmt))
3913         {
3914           unsigned i;
3915           for (i = 0; i < gimple_call_num_args (stmt); ++i)
3916             {
3917               tree arg = gimple_call_arg (stmt, i);
3918               while (handled_component_p (arg))
3919                 arg = TREE_OPERAND (arg, 0);
3920               if (TREE_CODE (arg) == MEM_REF
3921                   && TREE_OPERAND (arg, 0) == name
3922                   && integer_zerop (TREE_OPERAND (arg, 1))
3923                   && types_compatible_p (TREE_TYPE (arg),
3924                                          TREE_TYPE (TREE_TYPE (name)))
3925                   && !TREE_THIS_VOLATILE (arg))
3926                 uses_ok++;
3927             }
3928         }
3929
3930       /* If the number of valid uses does not match the number of
3931          uses in this stmt there is an unhandled use.  */
3932       FOR_EACH_IMM_USE_ON_STMT (use_p, ui)
3933         --uses_ok;
3934
3935       if (uses_ok != 0)
3936         ret = true;
3937
3938       if (ret)
3939         BREAK_FROM_IMM_USE_STMT (ui);
3940     }
3941
3942   return ret;
3943 }
3944
3945 /* Identify candidates for reduction for IPA-SRA based on their type and mark
3946    them in candidate_bitmap.  Note that these do not necessarily include
3947    parameter which are unused and thus can be removed.  Return true iff any
3948    such candidate has been found.  */
3949
3950 static bool
3951 find_param_candidates (void)
3952 {
3953   tree parm;
3954   int count = 0;
3955   bool ret = false;
3956   const char *msg;
3957
3958   for (parm = DECL_ARGUMENTS (current_function_decl);
3959        parm;
3960        parm = DECL_CHAIN (parm))
3961     {
3962       tree type = TREE_TYPE (parm);
3963       tree_node **slot;
3964
3965       count++;
3966
3967       if (TREE_THIS_VOLATILE (parm)
3968           || TREE_ADDRESSABLE (parm)
3969           || (!is_gimple_reg_type (type) && is_va_list_type (type)))
3970         continue;
3971
3972       if (is_unused_scalar_param (parm))
3973         {
3974           ret = true;
3975           continue;
3976         }
3977
3978       if (POINTER_TYPE_P (type))
3979         {
3980           type = TREE_TYPE (type);
3981
3982           if (TREE_CODE (type) == FUNCTION_TYPE
3983               || TYPE_VOLATILE (type)
3984               || (TREE_CODE (type) == ARRAY_TYPE
3985                   && TYPE_NONALIASED_COMPONENT (type))
3986               || !is_gimple_reg (parm)
3987               || is_va_list_type (type)
3988               || ptr_parm_has_direct_uses (parm))
3989             continue;
3990         }
3991       else if (!AGGREGATE_TYPE_P (type))
3992         continue;
3993
3994       if (!COMPLETE_TYPE_P (type)
3995           || !tree_fits_uhwi_p (TYPE_SIZE (type))
3996           || tree_to_uhwi (TYPE_SIZE (type)) == 0
3997           || (AGGREGATE_TYPE_P (type)
3998               && type_internals_preclude_sra_p (type, &msg)))
3999         continue;
4000
4001       bitmap_set_bit (candidate_bitmap, DECL_UID (parm));
4002       slot = candidates->find_slot_with_hash (parm, DECL_UID (parm), INSERT);
4003       *slot = parm;
4004
4005       ret = true;
4006       if (dump_file && (dump_flags & TDF_DETAILS))
4007         {
4008           fprintf (dump_file, "Candidate (%d): ", DECL_UID (parm));
4009           print_generic_expr (dump_file, parm, 0);
4010           fprintf (dump_file, "\n");
4011         }
4012     }
4013
4014   func_param_count = count;
4015   return ret;
4016 }
4017
4018 /* Callback of walk_aliased_vdefs, marks the access passed as DATA as
4019    maybe_modified. */
4020
4021 static bool
4022 mark_maybe_modified (ao_ref *ao ATTRIBUTE_UNUSED, tree vdef ATTRIBUTE_UNUSED,
4023                      void *data)
4024 {
4025   struct access *repr = (struct access *) data;
4026
4027   repr->grp_maybe_modified = 1;
4028   return true;
4029 }
4030
4031 /* Analyze what representatives (in linked lists accessible from
4032    REPRESENTATIVES) can be modified by side effects of statements in the
4033    current function.  */
4034
4035 static void
4036 analyze_modified_params (vec<access_p> representatives)
4037 {
4038   int i;
4039
4040   for (i = 0; i < func_param_count; i++)
4041     {
4042       struct access *repr;
4043
4044       for (repr = representatives[i];
4045            repr;
4046            repr = repr->next_grp)
4047         {
4048           struct access *access;
4049           bitmap visited;
4050           ao_ref ar;
4051
4052           if (no_accesses_p (repr))
4053             continue;
4054           if (!POINTER_TYPE_P (TREE_TYPE (repr->base))
4055               || repr->grp_maybe_modified)
4056             continue;
4057
4058           ao_ref_init (&ar, repr->expr);
4059           visited = BITMAP_ALLOC (NULL);
4060           for (access = repr; access; access = access->next_sibling)
4061             {
4062               /* All accesses are read ones, otherwise grp_maybe_modified would
4063                  be trivially set.  */
4064               walk_aliased_vdefs (&ar, gimple_vuse (access->stmt),
4065                                   mark_maybe_modified, repr, &visited);
4066               if (repr->grp_maybe_modified)
4067                 break;
4068             }
4069           BITMAP_FREE (visited);
4070         }
4071     }
4072 }
4073
4074 /* Propagate distances in bb_dereferences in the opposite direction than the
4075    control flow edges, in each step storing the maximum of the current value
4076    and the minimum of all successors.  These steps are repeated until the table
4077    stabilizes.  Note that BBs which might terminate the functions (according to
4078    final_bbs bitmap) never updated in this way.  */
4079
4080 static void
4081 propagate_dereference_distances (void)
4082 {
4083   basic_block bb;
4084
4085   auto_vec<basic_block> queue (last_basic_block_for_fn (cfun));
4086   queue.quick_push (ENTRY_BLOCK_PTR_FOR_FN (cfun));
4087   FOR_EACH_BB_FN (bb, cfun)
4088     {
4089       queue.quick_push (bb);
4090       bb->aux = bb;
4091     }
4092
4093   while (!queue.is_empty ())
4094     {
4095       edge_iterator ei;
4096       edge e;
4097       bool change = false;
4098       int i;
4099
4100       bb = queue.pop ();
4101       bb->aux = NULL;
4102
4103       if (bitmap_bit_p (final_bbs, bb->index))
4104         continue;
4105
4106       for (i = 0; i < func_param_count; i++)
4107         {
4108           int idx = bb->index * func_param_count + i;
4109           bool first = true;
4110           HOST_WIDE_INT inh = 0;
4111
4112           FOR_EACH_EDGE (e, ei, bb->succs)
4113           {
4114             int succ_idx = e->dest->index * func_param_count + i;
4115
4116             if (e->src == EXIT_BLOCK_PTR_FOR_FN (cfun))
4117               continue;
4118
4119             if (first)
4120               {
4121                 first = false;
4122                 inh = bb_dereferences [succ_idx];
4123               }
4124             else if (bb_dereferences [succ_idx] < inh)
4125               inh = bb_dereferences [succ_idx];
4126           }
4127
4128           if (!first && bb_dereferences[idx] < inh)
4129             {
4130               bb_dereferences[idx] = inh;
4131               change = true;
4132             }
4133         }
4134
4135       if (change && !bitmap_bit_p (final_bbs, bb->index))
4136         FOR_EACH_EDGE (e, ei, bb->preds)
4137           {
4138             if (e->src->aux)
4139               continue;
4140
4141             e->src->aux = e->src;
4142             queue.quick_push (e->src);
4143           }
4144     }
4145 }
4146
4147 /* Dump a dereferences TABLE with heading STR to file F.  */
4148
4149 static void
4150 dump_dereferences_table (FILE *f, const char *str, HOST_WIDE_INT *table)
4151 {
4152   basic_block bb;
4153
4154   fprintf (dump_file, "%s", str);
4155   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun),
4156                   EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb)
4157     {
4158       fprintf (f, "%4i  %i   ", bb->index, bitmap_bit_p (final_bbs, bb->index));
4159       if (bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
4160         {
4161           int i;
4162           for (i = 0; i < func_param_count; i++)
4163             {
4164               int idx = bb->index * func_param_count + i;
4165               fprintf (f, " %4" HOST_WIDE_INT_PRINT "d", table[idx]);
4166             }
4167         }
4168       fprintf (f, "\n");
4169     }
4170   fprintf (dump_file, "\n");
4171 }
4172
4173 /* Determine what (parts of) parameters passed by reference that are not
4174    assigned to are not certainly dereferenced in this function and thus the
4175    dereferencing cannot be safely moved to the caller without potentially
4176    introducing a segfault.  Mark such REPRESENTATIVES as
4177    grp_not_necessarilly_dereferenced.
4178
4179    The dereferenced maximum "distance," i.e. the offset + size of the accessed
4180    part is calculated rather than simple booleans are calculated for each
4181    pointer parameter to handle cases when only a fraction of the whole
4182    aggregate is allocated (see testsuite/gcc.c-torture/execute/ipa-sra-2.c for
4183    an example).
4184
4185    The maximum dereference distances for each pointer parameter and BB are
4186    already stored in bb_dereference.  This routine simply propagates these
4187    values upwards by propagate_dereference_distances and then compares the
4188    distances of individual parameters in the ENTRY BB to the equivalent
4189    distances of each representative of a (fraction of a) parameter.  */
4190
4191 static void
4192 analyze_caller_dereference_legality (vec<access_p> representatives)
4193 {
4194   int i;
4195
4196   if (dump_file && (dump_flags & TDF_DETAILS))
4197     dump_dereferences_table (dump_file,
4198                              "Dereference table before propagation:\n",
4199                              bb_dereferences);
4200
4201   propagate_dereference_distances ();
4202
4203   if (dump_file && (dump_flags & TDF_DETAILS))
4204     dump_dereferences_table (dump_file,
4205                              "Dereference table after propagation:\n",
4206                              bb_dereferences);
4207
4208   for (i = 0; i < func_param_count; i++)
4209     {
4210       struct access *repr = representatives[i];
4211       int idx = ENTRY_BLOCK_PTR_FOR_FN (cfun)->index * func_param_count + i;
4212
4213       if (!repr || no_accesses_p (repr))
4214         continue;
4215
4216       do
4217         {
4218           if ((repr->offset + repr->size) > bb_dereferences[idx])
4219             repr->grp_not_necessarilly_dereferenced = 1;
4220           repr = repr->next_grp;
4221         }
4222       while (repr);
4223     }
4224 }
4225
4226 /* Return the representative access for the parameter declaration PARM if it is
4227    a scalar passed by reference which is not written to and the pointer value
4228    is not used directly.  Thus, if it is legal to dereference it in the caller
4229    and we can rule out modifications through aliases, such parameter should be
4230    turned into one passed by value.  Return NULL otherwise.  */
4231
4232 static struct access *
4233 unmodified_by_ref_scalar_representative (tree parm)
4234 {
4235   int i, access_count;
4236   struct access *repr;
4237   vec<access_p> *access_vec;
4238
4239   access_vec = get_base_access_vector (parm);
4240   gcc_assert (access_vec);
4241   repr = (*access_vec)[0];
4242   if (repr->write)
4243     return NULL;
4244   repr->group_representative = repr;
4245
4246   access_count = access_vec->length ();
4247   for (i = 1; i < access_count; i++)
4248     {
4249       struct access *access = (*access_vec)[i];
4250       if (access->write)
4251         return NULL;
4252       access->group_representative = repr;
4253       access->next_sibling = repr->next_sibling;
4254       repr->next_sibling = access;
4255     }
4256
4257   repr->grp_read = 1;
4258   repr->grp_scalar_ptr = 1;
4259   return repr;
4260 }
4261
4262 /* Return true iff this ACCESS precludes IPA-SRA of the parameter it is
4263    associated with.  REQ_ALIGN is the minimum required alignment.  */
4264
4265 static bool
4266 access_precludes_ipa_sra_p (struct access *access, unsigned int req_align)
4267 {
4268   unsigned int exp_align;
4269   /* Avoid issues such as the second simple testcase in PR 42025.  The problem
4270      is incompatible assign in a call statement (and possibly even in asm
4271      statements).  This can be relaxed by using a new temporary but only for
4272      non-TREE_ADDRESSABLE types and is probably not worth the complexity. (In
4273      intraprocedural SRA we deal with this by keeping the old aggregate around,
4274      something we cannot do in IPA-SRA.)  */
4275   if (access->write
4276       && (is_gimple_call (access->stmt)
4277           || gimple_code (access->stmt) == GIMPLE_ASM))
4278     return true;
4279
4280   exp_align = get_object_alignment (access->expr);
4281   if (exp_align < req_align)
4282     return true;
4283
4284   return false;
4285 }
4286
4287
4288 /* Sort collected accesses for parameter PARM, identify representatives for
4289    each accessed region and link them together.  Return NULL if there are
4290    different but overlapping accesses, return the special ptr value meaning
4291    there are no accesses for this parameter if that is the case and return the
4292    first representative otherwise.  Set *RO_GRP if there is a group of accesses
4293    with only read (i.e. no write) accesses.  */
4294
4295 static struct access *
4296 splice_param_accesses (tree parm, bool *ro_grp)
4297 {
4298   int i, j, access_count, group_count;
4299   int agg_size, total_size = 0;
4300   struct access *access, *res, **prev_acc_ptr = &res;
4301   vec<access_p> *access_vec;
4302
4303   access_vec = get_base_access_vector (parm);
4304   if (!access_vec)
4305     return &no_accesses_representant;
4306   access_count = access_vec->length ();
4307
4308   access_vec->qsort (compare_access_positions);
4309
4310   i = 0;
4311   total_size = 0;
4312   group_count = 0;
4313   while (i < access_count)
4314     {
4315       bool modification;
4316       tree a1_alias_type;
4317       access = (*access_vec)[i];
4318       modification = access->write;
4319       if (access_precludes_ipa_sra_p (access, TYPE_ALIGN (access->type)))
4320         return NULL;
4321       a1_alias_type = reference_alias_ptr_type (access->expr);
4322
4323       /* Access is about to become group representative unless we find some
4324          nasty overlap which would preclude us from breaking this parameter
4325          apart. */
4326
4327       j = i + 1;
4328       while (j < access_count)
4329         {
4330           struct access *ac2 = (*access_vec)[j];
4331           if (ac2->offset != access->offset)
4332             {
4333               /* All or nothing law for parameters. */
4334               if (access->offset + access->size > ac2->offset)
4335                 return NULL;
4336               else
4337                 break;
4338             }
4339           else if (ac2->size != access->size)
4340             return NULL;
4341
4342           if (access_precludes_ipa_sra_p (ac2, TYPE_ALIGN (access->type))
4343               || (ac2->type != access->type
4344                   && (TREE_ADDRESSABLE (ac2->type)
4345                       || TREE_ADDRESSABLE (access->type)))
4346               || (reference_alias_ptr_type (ac2->expr) != a1_alias_type))
4347             return NULL;
4348
4349           modification |= ac2->write;
4350           ac2->group_representative = access;
4351           ac2->next_sibling = access->next_sibling;
4352           access->next_sibling = ac2;
4353           j++;
4354         }
4355
4356       group_count++;
4357       access->grp_maybe_modified = modification;
4358       if (!modification)
4359         *ro_grp = true;
4360       *prev_acc_ptr = access;
4361       prev_acc_ptr = &access->next_grp;
4362       total_size += access->size;
4363       i = j;
4364     }
4365
4366   if (POINTER_TYPE_P (TREE_TYPE (parm)))
4367     agg_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (TREE_TYPE (parm))));
4368   else
4369     agg_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (parm)));
4370   if (total_size >= agg_size)
4371     return NULL;
4372
4373   gcc_assert (group_count > 0);
4374   return res;
4375 }
4376
4377 /* Decide whether parameters with representative accesses given by REPR should
4378    be reduced into components.  */
4379
4380 static int
4381 decide_one_param_reduction (struct access *repr)
4382 {
4383   int total_size, cur_parm_size, agg_size, new_param_count, parm_size_limit;
4384   bool by_ref;
4385   tree parm;
4386
4387   parm = repr->base;
4388   cur_parm_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (parm)));
4389   gcc_assert (cur_parm_size > 0);
4390
4391   if (POINTER_TYPE_P (TREE_TYPE (parm)))
4392     {
4393       by_ref = true;
4394       agg_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (TREE_TYPE (parm))));
4395     }
4396   else
4397     {
4398       by_ref = false;
4399       agg_size = cur_parm_size;
4400     }
4401
4402   if (dump_file)
4403     {
4404       struct access *acc;
4405       fprintf (dump_file, "Evaluating PARAM group sizes for ");
4406       print_generic_expr (dump_file, parm, 0);
4407       fprintf (dump_file, " (UID: %u): \n", DECL_UID (parm));
4408       for (acc = repr; acc; acc = acc->next_grp)
4409         dump_access (dump_file, acc, true);
4410     }
4411
4412   total_size = 0;
4413   new_param_count = 0;
4414
4415   for (; repr; repr = repr->next_grp)
4416     {
4417       gcc_assert (parm == repr->base);
4418
4419       /* Taking the address of a non-addressable field is verboten.  */
4420       if (by_ref && repr->non_addressable)
4421         return 0;
4422
4423       /* Do not decompose a non-BLKmode param in a way that would
4424          create BLKmode params.  Especially for by-reference passing
4425          (thus, pointer-type param) this is hardly worthwhile.  */
4426       if (DECL_MODE (parm) != BLKmode
4427           && TYPE_MODE (repr->type) == BLKmode)
4428         return 0;
4429
4430       if (!by_ref || (!repr->grp_maybe_modified
4431                       && !repr->grp_not_necessarilly_dereferenced))
4432         total_size += repr->size;
4433       else
4434         total_size += cur_parm_size;
4435
4436       new_param_count++;
4437     }
4438
4439   gcc_assert (new_param_count > 0);
4440
4441   if (optimize_function_for_size_p (cfun))
4442     parm_size_limit = cur_parm_size;
4443   else
4444     parm_size_limit = (PARAM_VALUE (PARAM_IPA_SRA_PTR_GROWTH_FACTOR)
4445                        * cur_parm_size);
4446
4447   if (total_size < agg_size
4448       && total_size <= parm_size_limit)
4449     {
4450       if (dump_file)
4451         fprintf (dump_file, "    ....will be split into %i components\n",
4452                  new_param_count);
4453       return new_param_count;
4454     }
4455   else
4456     return 0;
4457 }
4458
4459 /* The order of the following enums is important, we need to do extra work for
4460    UNUSED_PARAMS, BY_VAL_ACCESSES and UNMODIF_BY_REF_ACCESSES.  */
4461 enum ipa_splicing_result { NO_GOOD_ACCESS, UNUSED_PARAMS, BY_VAL_ACCESSES,
4462                           MODIF_BY_REF_ACCESSES, UNMODIF_BY_REF_ACCESSES };
4463
4464 /* Identify representatives of all accesses to all candidate parameters for
4465    IPA-SRA.  Return result based on what representatives have been found. */
4466
4467 static enum ipa_splicing_result
4468 splice_all_param_accesses (vec<access_p> &representatives)
4469 {
4470   enum ipa_splicing_result result = NO_GOOD_ACCESS;
4471   tree parm;
4472   struct access *repr;
4473
4474   representatives.create (func_param_count);
4475
4476   for (parm = DECL_ARGUMENTS (current_function_decl);
4477        parm;
4478        parm = DECL_CHAIN (parm))
4479     {
4480       if (is_unused_scalar_param (parm))
4481         {
4482           representatives.quick_push (&no_accesses_representant);
4483           if (result == NO_GOOD_ACCESS)
4484             result = UNUSED_PARAMS;
4485         }
4486       else if (POINTER_TYPE_P (TREE_TYPE (parm))
4487                && is_gimple_reg_type (TREE_TYPE (TREE_TYPE (parm)))
4488                && bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
4489         {
4490           repr = unmodified_by_ref_scalar_representative (parm);
4491           representatives.quick_push (repr);
4492           if (repr)
4493             result = UNMODIF_BY_REF_ACCESSES;
4494         }
4495       else if (bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
4496         {
4497           bool ro_grp = false;
4498           repr = splice_param_accesses (parm, &ro_grp);
4499           representatives.quick_push (repr);
4500
4501           if (repr && !no_accesses_p (repr))
4502             {
4503               if (POINTER_TYPE_P (TREE_TYPE (parm)))
4504                 {
4505                   if (ro_grp)
4506                     result = UNMODIF_BY_REF_ACCESSES;
4507                   else if (result < MODIF_BY_REF_ACCESSES)
4508                     result = MODIF_BY_REF_ACCESSES;
4509                 }
4510               else if (result < BY_VAL_ACCESSES)
4511                 result = BY_VAL_ACCESSES;
4512             }
4513           else if (no_accesses_p (repr) && (result == NO_GOOD_ACCESS))
4514             result = UNUSED_PARAMS;
4515         }
4516       else
4517         representatives.quick_push (NULL);
4518     }
4519
4520   if (result == NO_GOOD_ACCESS)
4521     {
4522       representatives.release ();
4523       return NO_GOOD_ACCESS;
4524     }
4525
4526   return result;
4527 }
4528
4529 /* Return the index of BASE in PARMS.  Abort if it is not found.  */
4530
4531 static inline int
4532 get_param_index (tree base, vec<tree> parms)
4533 {
4534   int i, len;
4535
4536   len = parms.length ();
4537   for (i = 0; i < len; i++)
4538     if (parms[i] == base)
4539       return i;
4540   gcc_unreachable ();
4541 }
4542
4543 /* Convert the decisions made at the representative level into compact
4544    parameter adjustments.  REPRESENTATIVES are pointers to first
4545    representatives of each param accesses, ADJUSTMENTS_COUNT is the expected
4546    final number of adjustments.  */
4547
4548 static ipa_parm_adjustment_vec
4549 turn_representatives_into_adjustments (vec<access_p> representatives,
4550                                        int adjustments_count)
4551 {
4552   vec<tree> parms;
4553   ipa_parm_adjustment_vec adjustments;
4554   tree parm;
4555   int i;
4556
4557   gcc_assert (adjustments_count > 0);
4558   parms = ipa_get_vector_of_formal_parms (current_function_decl);
4559   adjustments.create (adjustments_count);
4560   parm = DECL_ARGUMENTS (current_function_decl);
4561   for (i = 0; i < func_param_count; i++, parm = DECL_CHAIN (parm))
4562     {
4563       struct access *repr = representatives[i];
4564
4565       if (!repr || no_accesses_p (repr))
4566         {
4567           struct ipa_parm_adjustment adj;
4568
4569           memset (&adj, 0, sizeof (adj));
4570           adj.base_index = get_param_index (parm, parms);
4571           adj.base = parm;
4572           if (!repr)
4573             adj.op = IPA_PARM_OP_COPY;
4574           else
4575             adj.op = IPA_PARM_OP_REMOVE;
4576           adj.arg_prefix = "ISRA";
4577           adjustments.quick_push (adj);
4578         }
4579       else
4580         {
4581           struct ipa_parm_adjustment adj;
4582           int index = get_param_index (parm, parms);
4583
4584           for (; repr; repr = repr->next_grp)
4585             {
4586               memset (&adj, 0, sizeof (adj));
4587               gcc_assert (repr->base == parm);
4588               adj.base_index = index;
4589               adj.base = repr->base;
4590               adj.type = repr->type;
4591               adj.alias_ptr_type = reference_alias_ptr_type (repr->expr);
4592               adj.offset = repr->offset;
4593               adj.reverse = repr->reverse;
4594               adj.by_ref = (POINTER_TYPE_P (TREE_TYPE (repr->base))
4595                             && (repr->grp_maybe_modified
4596                                 || repr->grp_not_necessarilly_dereferenced));
4597               adj.arg_prefix = "ISRA";
4598               adjustments.quick_push (adj);
4599             }
4600         }
4601     }
4602   parms.release ();
4603   return adjustments;
4604 }
4605
4606 /* Analyze the collected accesses and produce a plan what to do with the
4607    parameters in the form of adjustments, NULL meaning nothing.  */
4608
4609 static ipa_parm_adjustment_vec
4610 analyze_all_param_acesses (void)
4611 {
4612   enum ipa_splicing_result repr_state;
4613   bool proceed = false;
4614   int i, adjustments_count = 0;
4615   vec<access_p> representatives;
4616   ipa_parm_adjustment_vec adjustments;
4617
4618   repr_state = splice_all_param_accesses (representatives);
4619   if (repr_state == NO_GOOD_ACCESS)
4620     return ipa_parm_adjustment_vec ();
4621
4622   /* If there are any parameters passed by reference which are not modified
4623      directly, we need to check whether they can be modified indirectly.  */
4624   if (repr_state == UNMODIF_BY_REF_ACCESSES)
4625     {
4626       analyze_caller_dereference_legality (representatives);
4627       analyze_modified_params (representatives);
4628     }
4629
4630   for (i = 0; i < func_param_count; i++)
4631     {
4632       struct access *repr = representatives[i];
4633
4634       if (repr && !no_accesses_p (repr))
4635         {
4636           if (repr->grp_scalar_ptr)
4637             {
4638               adjustments_count++;
4639               if (repr->grp_not_necessarilly_dereferenced
4640                   || repr->grp_maybe_modified)
4641                 representatives[i] = NULL;
4642               else
4643                 {
4644                   proceed = true;
4645                   sra_stats.scalar_by_ref_to_by_val++;
4646                 }
4647             }
4648           else
4649             {
4650               int new_components = decide_one_param_reduction (repr);
4651
4652               if (new_components == 0)
4653                 {
4654                   representatives[i] = NULL;
4655                   adjustments_count++;
4656                 }
4657               else
4658                 {
4659                   adjustments_count += new_components;
4660                   sra_stats.aggregate_params_reduced++;
4661                   sra_stats.param_reductions_created += new_components;
4662                   proceed = true;
4663                 }
4664             }
4665         }
4666       else
4667         {
4668           if (no_accesses_p (repr))
4669             {
4670               proceed = true;
4671               sra_stats.deleted_unused_parameters++;
4672             }
4673           adjustments_count++;
4674         }
4675     }
4676
4677   if (!proceed && dump_file)
4678     fprintf (dump_file, "NOT proceeding to change params.\n");
4679
4680   if (proceed)
4681     adjustments = turn_representatives_into_adjustments (representatives,
4682                                                          adjustments_count);
4683   else
4684     adjustments = ipa_parm_adjustment_vec ();
4685
4686   representatives.release ();
4687   return adjustments;
4688 }
4689
4690 /* If a parameter replacement identified by ADJ does not yet exist in the form
4691    of declaration, create it and record it, otherwise return the previously
4692    created one.  */
4693
4694 static tree
4695 get_replaced_param_substitute (struct ipa_parm_adjustment *adj)
4696 {
4697   tree repl;
4698   if (!adj->new_ssa_base)
4699     {
4700       char *pretty_name = make_fancy_name (adj->base);
4701
4702       repl = create_tmp_reg (TREE_TYPE (adj->base), "ISR");
4703       DECL_NAME (repl) = get_identifier (pretty_name);
4704       obstack_free (&name_obstack, pretty_name);
4705
4706       adj->new_ssa_base = repl;
4707     }
4708   else
4709     repl = adj->new_ssa_base;
4710   return repl;
4711 }
4712
4713 /* Find the first adjustment for a particular parameter BASE in a vector of
4714    ADJUSTMENTS which is not a copy_param.  Return NULL if there is no such
4715    adjustment. */
4716
4717 static struct ipa_parm_adjustment *
4718 get_adjustment_for_base (ipa_parm_adjustment_vec adjustments, tree base)
4719 {
4720   int i, len;
4721
4722   len = adjustments.length ();
4723   for (i = 0; i < len; i++)
4724     {
4725       struct ipa_parm_adjustment *adj;
4726
4727       adj = &adjustments[i];
4728       if (adj->op != IPA_PARM_OP_COPY && adj->base == base)
4729         return adj;
4730     }
4731
4732   return NULL;
4733 }
4734
4735 /* If OLD_NAME, which is being defined by statement STMT, is an SSA_NAME of a
4736    parameter which is to be removed because its value is not used, create a new
4737    SSA_NAME relating to a replacement VAR_DECL, replace all uses of the
4738    original with it and return it.  If there is no need to re-map, return NULL.
4739    ADJUSTMENTS is a pointer to a vector of IPA-SRA adjustments.  */
4740
4741 static tree
4742 replace_removed_params_ssa_names (tree old_name, gimple *stmt,
4743                                   ipa_parm_adjustment_vec adjustments)
4744 {
4745   struct ipa_parm_adjustment *adj;
4746   tree decl, repl, new_name;
4747
4748   if (TREE_CODE (old_name) != SSA_NAME)
4749     return NULL;
4750
4751   decl = SSA_NAME_VAR (old_name);
4752   if (decl == NULL_TREE
4753       || TREE_CODE (decl) != PARM_DECL)
4754     return NULL;
4755
4756   adj = get_adjustment_for_base (adjustments, decl);
4757   if (!adj)
4758     return NULL;
4759
4760   repl = get_replaced_param_substitute (adj);
4761   new_name = make_ssa_name (repl, stmt);
4762   SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name)
4763     = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (old_name);
4764
4765   if (dump_file)
4766     {
4767       fprintf (dump_file, "replacing an SSA name of a removed param ");
4768       print_generic_expr (dump_file, old_name, 0);
4769       fprintf (dump_file, " with ");
4770       print_generic_expr (dump_file, new_name, 0);
4771       fprintf (dump_file, "\n");
4772     }
4773
4774   replace_uses_by (old_name, new_name);
4775   return new_name;
4776 }
4777
4778 /* If the statement STMT contains any expressions that need to replaced with a
4779    different one as noted by ADJUSTMENTS, do so.  Handle any potential type
4780    incompatibilities (GSI is used to accommodate conversion statements and must
4781    point to the statement).  Return true iff the statement was modified.  */
4782
4783 static bool
4784 sra_ipa_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi,
4785                        ipa_parm_adjustment_vec adjustments)
4786 {
4787   tree *lhs_p, *rhs_p;
4788   bool any;
4789
4790   if (!gimple_assign_single_p (stmt))
4791     return false;
4792
4793   rhs_p = gimple_assign_rhs1_ptr (stmt);
4794   lhs_p = gimple_assign_lhs_ptr (stmt);
4795
4796   any = ipa_modify_expr (rhs_p, false, adjustments);
4797   any |= ipa_modify_expr (lhs_p, false, adjustments);
4798   if (any)
4799     {
4800       tree new_rhs = NULL_TREE;
4801
4802       if (!useless_type_conversion_p (TREE_TYPE (*lhs_p), TREE_TYPE (*rhs_p)))
4803         {
4804           if (TREE_CODE (*rhs_p) == CONSTRUCTOR)
4805             {
4806               /* V_C_Es of constructors can cause trouble (PR 42714).  */
4807               if (is_gimple_reg_type (TREE_TYPE (*lhs_p)))
4808                 *rhs_p = build_zero_cst (TREE_TYPE (*lhs_p));
4809               else
4810                 *rhs_p = build_constructor (TREE_TYPE (*lhs_p),
4811                                             NULL);
4812             }
4813           else
4814             new_rhs = fold_build1_loc (gimple_location (stmt),
4815                                        VIEW_CONVERT_EXPR, TREE_TYPE (*lhs_p),
4816                                        *rhs_p);
4817         }
4818       else if (REFERENCE_CLASS_P (*rhs_p)
4819                && is_gimple_reg_type (TREE_TYPE (*lhs_p))
4820                && !is_gimple_reg (*lhs_p))
4821         /* This can happen when an assignment in between two single field
4822            structures is turned into an assignment in between two pointers to
4823            scalars (PR 42237).  */
4824         new_rhs = *rhs_p;
4825
4826       if (new_rhs)
4827         {
4828           tree tmp = force_gimple_operand_gsi (gsi, new_rhs, true, NULL_TREE,
4829                                                true, GSI_SAME_STMT);
4830
4831           gimple_assign_set_rhs_from_tree (gsi, tmp);
4832         }
4833
4834       return true;
4835     }
4836
4837   return false;
4838 }
4839
4840 /* Traverse the function body and all modifications as described in
4841    ADJUSTMENTS.  Return true iff the CFG has been changed.  */
4842
4843 bool
4844 ipa_sra_modify_function_body (ipa_parm_adjustment_vec adjustments)
4845 {
4846   bool cfg_changed = false;
4847   basic_block bb;
4848
4849   FOR_EACH_BB_FN (bb, cfun)
4850     {
4851       gimple_stmt_iterator gsi;
4852
4853       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
4854         {
4855           gphi *phi = as_a <gphi *> (gsi_stmt (gsi));
4856           tree new_lhs, old_lhs = gimple_phi_result (phi);
4857           new_lhs = replace_removed_params_ssa_names (old_lhs, phi, adjustments);
4858           if (new_lhs)
4859             {
4860               gimple_phi_set_result (phi, new_lhs);
4861               release_ssa_name (old_lhs);
4862             }
4863         }
4864
4865       gsi = gsi_start_bb (bb);
4866       while (!gsi_end_p (gsi))
4867         {
4868           gimple *stmt = gsi_stmt (gsi);
4869           bool modified = false;
4870           tree *t;
4871           unsigned i;
4872
4873           switch (gimple_code (stmt))
4874             {
4875             case GIMPLE_RETURN:
4876               t = gimple_return_retval_ptr (as_a <greturn *> (stmt));
4877               if (*t != NULL_TREE)
4878                 modified |= ipa_modify_expr (t, true, adjustments);
4879               break;
4880
4881             case GIMPLE_ASSIGN:
4882               modified |= sra_ipa_modify_assign (stmt, &gsi, adjustments);
4883               break;
4884
4885             case GIMPLE_CALL:
4886               /* Operands must be processed before the lhs.  */
4887               for (i = 0; i < gimple_call_num_args (stmt); i++)
4888                 {
4889                   t = gimple_call_arg_ptr (stmt, i);
4890                   modified |= ipa_modify_expr (t, true, adjustments);
4891                 }
4892
4893               if (gimple_call_lhs (stmt))
4894                 {
4895                   t = gimple_call_lhs_ptr (stmt);
4896                   modified |= ipa_modify_expr (t, false, adjustments);
4897                 }
4898               break;
4899
4900             case GIMPLE_ASM:
4901               {
4902                 gasm *asm_stmt = as_a <gasm *> (stmt);
4903                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
4904                   {
4905                     t = &TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
4906                     modified |= ipa_modify_expr (t, true, adjustments);
4907                   }
4908                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
4909                   {
4910                     t = &TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
4911                     modified |= ipa_modify_expr (t, false, adjustments);
4912                   }
4913               }
4914               break;
4915
4916             default:
4917               break;
4918             }
4919
4920           def_operand_p defp;
4921           ssa_op_iter iter;
4922           FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_DEF)
4923             {
4924               tree old_def = DEF_FROM_PTR (defp);
4925               if (tree new_def = replace_removed_params_ssa_names (old_def, stmt,
4926                                                                    adjustments))
4927                 {
4928                   SET_DEF (defp, new_def);
4929                   release_ssa_name (old_def);
4930                   modified = true;
4931                 }
4932             }
4933
4934           if (modified)
4935             {
4936               update_stmt (stmt);
4937               if (maybe_clean_eh_stmt (stmt)
4938                   && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
4939                 cfg_changed = true;
4940             }
4941           gsi_next (&gsi);
4942         }
4943     }
4944
4945   return cfg_changed;
4946 }
4947
4948 /* Call gimple_debug_bind_reset_value on all debug statements describing
4949    gimple register parameters that are being removed or replaced.  */
4950
4951 static void
4952 sra_ipa_reset_debug_stmts (ipa_parm_adjustment_vec adjustments)
4953 {
4954   int i, len;
4955   gimple_stmt_iterator *gsip = NULL, gsi;
4956
4957   if (MAY_HAVE_DEBUG_STMTS && single_succ_p (ENTRY_BLOCK_PTR_FOR_FN (cfun)))
4958     {
4959       gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
4960       gsip = &gsi;
4961     }
4962   len = adjustments.length ();
4963   for (i = 0; i < len; i++)
4964     {
4965       struct ipa_parm_adjustment *adj;
4966       imm_use_iterator ui;
4967       gimple *stmt;
4968       gdebug *def_temp;
4969       tree name, vexpr, copy = NULL_TREE;
4970       use_operand_p use_p;
4971
4972       adj = &adjustments[i];
4973       if (adj->op == IPA_PARM_OP_COPY || !is_gimple_reg (adj->base))
4974         continue;
4975       name = ssa_default_def (cfun, adj->base);
4976       vexpr = NULL;
4977       if (name)
4978         FOR_EACH_IMM_USE_STMT (stmt, ui, name)
4979           {
4980             if (gimple_clobber_p (stmt))
4981               {
4982                 gimple_stmt_iterator cgsi = gsi_for_stmt (stmt);
4983                 unlink_stmt_vdef (stmt);
4984                 gsi_remove (&cgsi, true);
4985                 release_defs (stmt);
4986                 continue;
4987               }
4988             /* All other users must have been removed by
4989                ipa_sra_modify_function_body.  */
4990             gcc_assert (is_gimple_debug (stmt));
4991             if (vexpr == NULL && gsip != NULL)
4992               {
4993                 gcc_assert (TREE_CODE (adj->base) == PARM_DECL);
4994                 vexpr = make_node (DEBUG_EXPR_DECL);
4995                 def_temp = gimple_build_debug_source_bind (vexpr, adj->base,
4996                                                            NULL);
4997                 DECL_ARTIFICIAL (vexpr) = 1;
4998                 TREE_TYPE (vexpr) = TREE_TYPE (name);
4999                 DECL_MODE (vexpr) = DECL_MODE (adj->base);
5000                 gsi_insert_before (gsip, def_temp, GSI_SAME_STMT);
5001               }
5002             if (vexpr)
5003               {
5004                 FOR_EACH_IMM_USE_ON_STMT (use_p, ui)
5005                   SET_USE (use_p, vexpr);
5006               }
5007             else
5008               gimple_debug_bind_reset_value (stmt);
5009             update_stmt (stmt);
5010           }
5011       /* Create a VAR_DECL for debug info purposes.  */
5012       if (!DECL_IGNORED_P (adj->base))
5013         {
5014           copy = build_decl (DECL_SOURCE_LOCATION (current_function_decl),
5015                              VAR_DECL, DECL_NAME (adj->base),
5016                              TREE_TYPE (adj->base));
5017           if (DECL_PT_UID_SET_P (adj->base))
5018             SET_DECL_PT_UID (copy, DECL_PT_UID (adj->base));
5019           TREE_ADDRESSABLE (copy) = TREE_ADDRESSABLE (adj->base);
5020           TREE_READONLY (copy) = TREE_READONLY (adj->base);
5021           TREE_THIS_VOLATILE (copy) = TREE_THIS_VOLATILE (adj->base);
5022           DECL_GIMPLE_REG_P (copy) = DECL_GIMPLE_REG_P (adj->base);
5023           DECL_ARTIFICIAL (copy) = DECL_ARTIFICIAL (adj->base);
5024           DECL_IGNORED_P (copy) = DECL_IGNORED_P (adj->base);
5025           DECL_ABSTRACT_ORIGIN (copy) = DECL_ORIGIN (adj->base);
5026           DECL_SEEN_IN_BIND_EXPR_P (copy) = 1;
5027           SET_DECL_RTL (copy, 0);
5028           TREE_USED (copy) = 1;
5029           DECL_CONTEXT (copy) = current_function_decl;
5030           add_local_decl (cfun, copy);
5031           DECL_CHAIN (copy) =
5032             BLOCK_VARS (DECL_INITIAL (current_function_decl));
5033           BLOCK_VARS (DECL_INITIAL (current_function_decl)) = copy;
5034         }
5035       if (gsip != NULL && copy && target_for_debug_bind (adj->base))
5036         {
5037           gcc_assert (TREE_CODE (adj->base) == PARM_DECL);
5038           if (vexpr)
5039             def_temp = gimple_build_debug_bind (copy, vexpr, NULL);
5040           else
5041             def_temp = gimple_build_debug_source_bind (copy, adj->base,
5042                                                        NULL);
5043           gsi_insert_before (gsip, def_temp, GSI_SAME_STMT);
5044         }
5045     }
5046 }
5047
5048 /* Return false if all callers have at least as many actual arguments as there
5049    are formal parameters in the current function and that their types
5050    match.  */
5051
5052 static bool
5053 some_callers_have_mismatched_arguments_p (struct cgraph_node *node,
5054                                           void *data ATTRIBUTE_UNUSED)
5055 {
5056   struct cgraph_edge *cs;
5057   for (cs = node->callers; cs; cs = cs->next_caller)
5058     if (!cs->call_stmt || !callsite_arguments_match_p (cs->call_stmt))
5059       return true;
5060
5061   return false;
5062 }
5063
5064 /* Return false if all callers have vuse attached to a call statement.  */
5065
5066 static bool
5067 some_callers_have_no_vuse_p (struct cgraph_node *node,
5068                              void *data ATTRIBUTE_UNUSED)
5069 {
5070   struct cgraph_edge *cs;
5071   for (cs = node->callers; cs; cs = cs->next_caller)
5072     if (!cs->call_stmt || !gimple_vuse (cs->call_stmt))
5073       return true;
5074
5075   return false;
5076 }
5077
5078 /* Convert all callers of NODE.  */
5079
5080 static bool
5081 convert_callers_for_node (struct cgraph_node *node,
5082                           void *data)
5083 {
5084   ipa_parm_adjustment_vec *adjustments = (ipa_parm_adjustment_vec *) data;
5085   bitmap recomputed_callers = BITMAP_ALLOC (NULL);
5086   struct cgraph_edge *cs;
5087
5088   for (cs = node->callers; cs; cs = cs->next_caller)
5089     {
5090       push_cfun (DECL_STRUCT_FUNCTION (cs->caller->decl));
5091
5092       if (dump_file)
5093         fprintf (dump_file, "Adjusting call %s/%i -> %s/%i\n",
5094                  xstrdup_for_dump (cs->caller->name ()),
5095                  cs->caller->order,
5096                  xstrdup_for_dump (cs->callee->name ()),
5097                  cs->callee->order);
5098
5099       ipa_modify_call_arguments (cs, cs->call_stmt, *adjustments);
5100
5101       pop_cfun ();
5102     }
5103
5104   for (cs = node->callers; cs; cs = cs->next_caller)
5105     if (bitmap_set_bit (recomputed_callers, cs->caller->uid)
5106         && gimple_in_ssa_p (DECL_STRUCT_FUNCTION (cs->caller->decl)))
5107       compute_inline_parameters (cs->caller, true);
5108   BITMAP_FREE (recomputed_callers);
5109
5110   return true;
5111 }
5112
5113 /* Convert all callers of NODE to pass parameters as given in ADJUSTMENTS.  */
5114
5115 static void
5116 convert_callers (struct cgraph_node *node, tree old_decl,
5117                  ipa_parm_adjustment_vec adjustments)
5118 {
5119   basic_block this_block;
5120
5121   node->call_for_symbol_and_aliases (convert_callers_for_node,
5122                                      &adjustments, false);
5123
5124   if (!encountered_recursive_call)
5125     return;
5126
5127   FOR_EACH_BB_FN (this_block, cfun)
5128     {
5129       gimple_stmt_iterator gsi;
5130
5131       for (gsi = gsi_start_bb (this_block); !gsi_end_p (gsi); gsi_next (&gsi))
5132         {
5133           gcall *stmt;
5134           tree call_fndecl;
5135           stmt = dyn_cast <gcall *> (gsi_stmt (gsi));
5136           if (!stmt)
5137             continue;
5138           call_fndecl = gimple_call_fndecl (stmt);
5139           if (call_fndecl == old_decl)
5140             {
5141               if (dump_file)
5142                 fprintf (dump_file, "Adjusting recursive call");
5143               gimple_call_set_fndecl (stmt, node->decl);
5144               ipa_modify_call_arguments (NULL, stmt, adjustments);
5145             }
5146         }
5147     }
5148
5149   return;
5150 }
5151
5152 /* Perform all the modification required in IPA-SRA for NODE to have parameters
5153    as given in ADJUSTMENTS.  Return true iff the CFG has been changed.  */
5154
5155 static bool
5156 modify_function (struct cgraph_node *node, ipa_parm_adjustment_vec adjustments)
5157 {
5158   struct cgraph_node *new_node;
5159   bool cfg_changed;
5160
5161   cgraph_edge::rebuild_edges ();
5162   free_dominance_info (CDI_DOMINATORS);
5163   pop_cfun ();
5164
5165   /* This must be done after rebuilding cgraph edges for node above.
5166      Otherwise any recursive calls to node that are recorded in
5167      redirect_callers will be corrupted.  */
5168   vec<cgraph_edge *> redirect_callers = node->collect_callers ();
5169   new_node = node->create_version_clone_with_body (redirect_callers, NULL,
5170                                                    NULL, false, NULL, NULL,
5171                                                    "isra");
5172   redirect_callers.release ();
5173
5174   push_cfun (DECL_STRUCT_FUNCTION (new_node->decl));
5175   ipa_modify_formal_parameters (current_function_decl, adjustments);
5176   cfg_changed = ipa_sra_modify_function_body (adjustments);
5177   sra_ipa_reset_debug_stmts (adjustments);
5178   convert_callers (new_node, node->decl, adjustments);
5179   new_node->make_local ();
5180   return cfg_changed;
5181 }
5182
5183 /* Means of communication between ipa_sra_check_caller and
5184    ipa_sra_preliminary_function_checks.  */
5185
5186 struct ipa_sra_check_caller_data
5187 {
5188   bool has_callers;
5189   bool bad_arg_alignment;
5190   bool has_thunk;
5191 };
5192
5193 /* If NODE has a caller, mark that fact in DATA which is pointer to
5194    ipa_sra_check_caller_data.  Also check all aggregate arguments in all known
5195    calls if they are unit aligned and if not, set the appropriate flag in DATA
5196    too. */
5197
5198 static bool
5199 ipa_sra_check_caller (struct cgraph_node *node, void *data)
5200 {
5201   if (!node->callers)
5202     return false;
5203
5204   struct ipa_sra_check_caller_data *iscc;
5205   iscc = (struct ipa_sra_check_caller_data *) data;
5206   iscc->has_callers = true;
5207
5208   for (cgraph_edge *cs = node->callers; cs; cs = cs->next_caller)
5209     {
5210       if (cs->caller->thunk.thunk_p)
5211         {
5212           iscc->has_thunk = true;
5213           return true;
5214         }
5215       gimple *call_stmt = cs->call_stmt;
5216       unsigned count = gimple_call_num_args (call_stmt);
5217       for (unsigned i = 0; i < count; i++)
5218         {
5219           tree arg = gimple_call_arg (call_stmt, i);
5220           if (is_gimple_reg (arg))
5221               continue;
5222
5223           tree offset;
5224           HOST_WIDE_INT bitsize, bitpos;
5225           machine_mode mode;
5226           int unsignedp, reversep, volatilep = 0;
5227           get_inner_reference (arg, &bitsize, &bitpos, &offset, &mode,
5228                                &unsignedp, &reversep, &volatilep, false);
5229           if (bitpos % BITS_PER_UNIT)
5230             {
5231               iscc->bad_arg_alignment = true;
5232               return true;
5233             }
5234         }
5235     }
5236
5237   return false;
5238 }
5239
5240 /* Return false the function is apparently unsuitable for IPA-SRA based on it's
5241    attributes, return true otherwise.  NODE is the cgraph node of the current
5242    function.  */
5243
5244 static bool
5245 ipa_sra_preliminary_function_checks (struct cgraph_node *node)
5246 {
5247   if (!node->can_be_local_p ())
5248     {
5249       if (dump_file)
5250         fprintf (dump_file, "Function not local to this compilation unit.\n");
5251       return false;
5252     }
5253
5254   if (!node->local.can_change_signature)
5255     {
5256       if (dump_file)
5257         fprintf (dump_file, "Function can not change signature.\n");
5258       return false;
5259     }
5260
5261   if (!tree_versionable_function_p (node->decl))
5262     {
5263       if (dump_file)
5264         fprintf (dump_file, "Function is not versionable.\n");
5265       return false;
5266     }
5267
5268   if (!opt_for_fn (node->decl, optimize)
5269       || !opt_for_fn (node->decl, flag_ipa_sra))
5270     {
5271       if (dump_file)
5272         fprintf (dump_file, "Function not optimized.\n");
5273       return false;
5274     }
5275
5276   if (DECL_VIRTUAL_P (current_function_decl))
5277     {
5278       if (dump_file)
5279         fprintf (dump_file, "Function is a virtual method.\n");
5280       return false;
5281     }
5282
5283   if ((DECL_ONE_ONLY (node->decl) || DECL_EXTERNAL (node->decl))
5284       && inline_summaries->get (node)->size >= MAX_INLINE_INSNS_AUTO)
5285     {
5286       if (dump_file)
5287         fprintf (dump_file, "Function too big to be made truly local.\n");
5288       return false;
5289     }
5290
5291   if (cfun->stdarg)
5292     {
5293       if (dump_file)
5294         fprintf (dump_file, "Function uses stdarg. \n");
5295       return false;
5296     }
5297
5298   if (TYPE_ATTRIBUTES (TREE_TYPE (node->decl)))
5299     return false;
5300
5301   if (DECL_DISREGARD_INLINE_LIMITS (node->decl))
5302     {
5303       if (dump_file)
5304         fprintf (dump_file, "Always inline function will be inlined "
5305                  "anyway. \n");
5306       return false;
5307     }
5308
5309   struct ipa_sra_check_caller_data iscc;
5310   memset (&iscc, 0, sizeof(iscc));
5311   node->call_for_symbol_and_aliases (ipa_sra_check_caller, &iscc, true);
5312   if (!iscc.has_callers)
5313     {
5314       if (dump_file)
5315         fprintf (dump_file,
5316                  "Function has no callers in this compilation unit.\n");
5317       return false;
5318     }
5319
5320   if (iscc.bad_arg_alignment)
5321     {
5322       if (dump_file)
5323         fprintf (dump_file,
5324                  "A function call has an argument with non-unit alignment.\n");
5325       return false;
5326     }
5327
5328   if (iscc.has_thunk)
5329     {
5330       if (dump_file)
5331         fprintf (dump_file,
5332                  "A has thunk.\n");
5333       return false;
5334     }
5335
5336   return true;
5337 }
5338
5339 /* Perform early interprocedural SRA.  */
5340
5341 static unsigned int
5342 ipa_early_sra (void)
5343 {
5344   struct cgraph_node *node = cgraph_node::get (current_function_decl);
5345   ipa_parm_adjustment_vec adjustments;
5346   int ret = 0;
5347
5348   if (!ipa_sra_preliminary_function_checks (node))
5349     return 0;
5350
5351   sra_initialize ();
5352   sra_mode = SRA_MODE_EARLY_IPA;
5353
5354   if (!find_param_candidates ())
5355     {
5356       if (dump_file)
5357         fprintf (dump_file, "Function has no IPA-SRA candidates.\n");
5358       goto simple_out;
5359     }
5360
5361   if (node->call_for_symbol_and_aliases
5362        (some_callers_have_mismatched_arguments_p, NULL, true))
5363     {
5364       if (dump_file)
5365         fprintf (dump_file, "There are callers with insufficient number of "
5366                  "arguments or arguments with type mismatches.\n");
5367       goto simple_out;
5368     }
5369
5370   if (node->call_for_symbol_and_aliases
5371        (some_callers_have_no_vuse_p, NULL, true))
5372     {
5373       if (dump_file)
5374         fprintf (dump_file, "There are callers with no VUSE attached "
5375                  "to a call stmt.\n");
5376       goto simple_out;
5377     }
5378
5379   bb_dereferences = XCNEWVEC (HOST_WIDE_INT,
5380                                  func_param_count
5381                                  * last_basic_block_for_fn (cfun));
5382   final_bbs = BITMAP_ALLOC (NULL);
5383
5384   scan_function ();
5385   if (encountered_apply_args)
5386     {
5387       if (dump_file)
5388         fprintf (dump_file, "Function calls  __builtin_apply_args().\n");
5389       goto out;
5390     }
5391
5392   if (encountered_unchangable_recursive_call)
5393     {
5394       if (dump_file)
5395         fprintf (dump_file, "Function calls itself with insufficient "
5396                  "number of arguments.\n");
5397       goto out;
5398     }
5399
5400   adjustments = analyze_all_param_acesses ();
5401   if (!adjustments.exists ())
5402     goto out;
5403   if (dump_file)
5404     ipa_dump_param_adjustments (dump_file, adjustments, current_function_decl);
5405
5406   if (modify_function (node, adjustments))
5407     ret = TODO_update_ssa | TODO_cleanup_cfg;
5408   else
5409     ret = TODO_update_ssa;
5410   adjustments.release ();
5411
5412   statistics_counter_event (cfun, "Unused parameters deleted",
5413                             sra_stats.deleted_unused_parameters);
5414   statistics_counter_event (cfun, "Scalar parameters converted to by-value",
5415                             sra_stats.scalar_by_ref_to_by_val);
5416   statistics_counter_event (cfun, "Aggregate parameters broken up",
5417                             sra_stats.aggregate_params_reduced);
5418   statistics_counter_event (cfun, "Aggregate parameter components created",
5419                             sra_stats.param_reductions_created);
5420
5421  out:
5422   BITMAP_FREE (final_bbs);
5423   free (bb_dereferences);
5424  simple_out:
5425   sra_deinitialize ();
5426   return ret;
5427 }
5428
5429 namespace {
5430
5431 const pass_data pass_data_early_ipa_sra =
5432 {
5433   GIMPLE_PASS, /* type */
5434   "eipa_sra", /* name */
5435   OPTGROUP_NONE, /* optinfo_flags */
5436   TV_IPA_SRA, /* tv_id */
5437   0, /* properties_required */
5438   0, /* properties_provided */
5439   0, /* properties_destroyed */
5440   0, /* todo_flags_start */
5441   TODO_dump_symtab, /* todo_flags_finish */
5442 };
5443
5444 class pass_early_ipa_sra : public gimple_opt_pass
5445 {
5446 public:
5447   pass_early_ipa_sra (gcc::context *ctxt)
5448     : gimple_opt_pass (pass_data_early_ipa_sra, ctxt)
5449   {}
5450
5451   /* opt_pass methods: */
5452   virtual bool gate (function *) { return flag_ipa_sra && dbg_cnt (eipa_sra); }
5453   virtual unsigned int execute (function *) { return ipa_early_sra (); }
5454
5455 }; // class pass_early_ipa_sra
5456
5457 } // anon namespace
5458
5459 gimple_opt_pass *
5460 make_pass_early_ipa_sra (gcc::context *ctxt)
5461 {
5462   return new pass_early_ipa_sra (ctxt);
5463 }