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) 2008-2018 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-param-manipulation.h"
 101 #include "ipa-prop.h"
 102 #include "params.h"
 103 #include "dbgcnt.h"
 104 #include "tree-inline.h"
 105 #include "ipa-fnsummary.h"
 106 #include "ipa-utils.h"
 107 #include "builtins.h"
 108
 109 /* Enumeration of all aggregate reductions we can do.  */
 110 enum sra_mode { SRA_MODE_EARLY_IPA,   /* early call regularization */
 111                 SRA_MODE_EARLY_INTRA, /* early intraprocedural SRA */
 112                 SRA_MODE_INTRA };     /* late intraprocedural SRA */
 113
 114 /* Global variable describing which aggregate reduction we are performing at
 115    the moment.  */
 116 static enum sra_mode sra_mode;
 117
 118 struct assign_link;
 119
 120 /* ACCESS represents each access to an aggregate variable (as a whole or a
 121    part).  It can also represent a group of accesses that refer to exactly the
 122    same fragment of an aggregate (i.e. those that have exactly the same offset
 123    and size).  Such representatives for a single aggregate, once determined,
 124    are linked in a linked list and have the group fields set.
 125
 126    Moreover, when doing intraprocedural SRA, a tree is built from those
 127    representatives (by the means of first_child and next_sibling pointers), in
 128    which all items in a subtree are "within" the root, i.e. their offset is
 129    greater or equal to offset of the root and offset+size is smaller or equal
 130    to offset+size of the root.  Children of an access are sorted by offset.
 131
 132    Note that accesses to parts of vector and complex number types always
 133    represented by an access to the whole complex number or a vector.  It is a
 134    duty of the modifying functions to replace them appropriately.  */
 135
 136 struct access
 137 {
 138   /* Values returned by  `get_ref_base_and_extent' for each component reference
 139      If EXPR isn't a component reference  just set `BASE = EXPR', `OFFSET = 0',
 140      `SIZE = TREE_SIZE (TREE_TYPE (expr))'.  */
 141   HOST_WIDE_INT offset;
 142   HOST_WIDE_INT size;
 143   tree base;
 144
 145   /* Expression.  It is context dependent so do not use it to create new
 146      expressions to access the original aggregate.  See PR 42154 for a
 147      testcase.  */
 148   tree expr;
 149   /* Type.  */
 150   tree type;
 151
 152   /* The statement this access belongs to.  */
 153   gimple *stmt;
 154
 155   /* Next group representative for this aggregate. */
 156   struct access *next_grp;
 157
 158   /* Pointer to the group representative.  Pointer to itself if the struct is
 159      the representative.  */
 160   struct access *group_representative;
 161
 162   /* After access tree has been constructed, this points to the parent of the
 163      current access, if there is one.  NULL for roots.  */
 164   struct access *parent;
 165
 166   /* If this access has any children (in terms of the definition above), this
 167      points to the first one.  */
 168   struct access *first_child;
 169
 170   /* In intraprocedural SRA, pointer to the next sibling in the access tree as
 171      described above.  In IPA-SRA this is a pointer to the next access
 172      belonging to the same group (having the same representative).  */
 173   struct access *next_sibling;
 174
 175   /* Pointers to the first and last element in the linked list of assign
 176      links.  */
 177   struct assign_link *first_link, *last_link;
 178
 179   /* Pointer to the next access in the work queue.  */
 180   struct access *next_queued;
 181
 182   /* Replacement variable for this access "region."  Never to be accessed
 183      directly, always only by the means of get_access_replacement() and only
 184      when grp_to_be_replaced flag is set.  */
 185   tree replacement_decl;
 186
 187   /* Is this access an access to a non-addressable field? */
 188   unsigned non_addressable : 1;
 189
 190   /* Is this access made in reverse storage order? */
 191   unsigned reverse : 1;
 192
 193   /* Is this particular access write access? */
 194   unsigned write : 1;
 195
 196   /* Is this access currently in the work queue?  */
 197   unsigned grp_queued : 1;
 198
 199   /* Does this group contain a write access?  This flag is propagated down the
 200      access tree.  */
 201   unsigned grp_write : 1;
 202
 203   /* Does this group contain a read access?  This flag is propagated down the
 204      access tree.  */
 205   unsigned grp_read : 1;
 206
 207   /* Does this group contain a read access that comes from an assignment
 208      statement?  This flag is propagated down the access tree.  */
 209   unsigned grp_assignment_read : 1;
 210
 211   /* Does this group contain a write access that comes from an assignment
 212      statement?  This flag is propagated down the access tree.  */
 213   unsigned grp_assignment_write : 1;
 214
 215   /* Does this group contain a read access through a scalar type?  This flag is
 216      not propagated in the access tree in any direction.  */
 217   unsigned grp_scalar_read : 1;
 218
 219   /* Does this group contain a write access through a scalar type?  This flag
 220      is not propagated in the access tree in any direction.  */
 221   unsigned grp_scalar_write : 1;
 222
 223   /* Is this access an artificial one created to scalarize some record
 224      entirely? */
 225   unsigned grp_total_scalarization : 1;
 226
 227   /* Other passes of the analysis use this bit to make function
 228      analyze_access_subtree create scalar replacements for this group if
 229      possible.  */
 230   unsigned grp_hint : 1;
 231
 232   /* Is the subtree rooted in this access fully covered by scalar
 233      replacements?  */
 234   unsigned grp_covered : 1;
 235
 236   /* If set to true, this access and all below it in an access tree must not be
 237      scalarized.  */
 238   unsigned grp_unscalarizable_region : 1;
 239
 240   /* Whether data have been written to parts of the aggregate covered by this
 241      access which is not to be scalarized.  This flag is propagated up in the
 242      access tree.  */
 243   unsigned grp_unscalarized_data : 1;
 244
 245   /* Does this access and/or group contain a write access through a
 246      BIT_FIELD_REF?  */
 247   unsigned grp_partial_lhs : 1;
 248
 249   /* Set when a scalar replacement should be created for this variable.  */
 250   unsigned grp_to_be_replaced : 1;
 251
 252   /* Set when we want a replacement for the sole purpose of having it in
 253      generated debug statements.  */
 254   unsigned grp_to_be_debug_replaced : 1;
 255
 256   /* Should TREE_NO_WARNING of a replacement be set?  */
 257   unsigned grp_no_warning : 1;
 258
 259   /* Is it possible that the group refers to data which might be (directly or
 260      otherwise) modified?  */
 261   unsigned grp_maybe_modified : 1;
 262
 263   /* Set when this is a representative of a pointer to scalar (i.e. by
 264      reference) parameter which we consider for turning into a plain scalar
 265      (i.e. a by value parameter).  */
 266   unsigned grp_scalar_ptr : 1;
 267
 268   /* Set when we discover that this pointer is not safe to dereference in the
 269      caller.  */
 270   unsigned grp_not_necessarilly_dereferenced : 1;
 271 };
 272
 273 typedef struct access *access_p;
 274
 275
 276 /* Alloc pool for allocating access structures.  */
 277 static object_allocator<struct access> access_pool ("SRA accesses");
 278
 279 /* A structure linking lhs and rhs accesses from an aggregate assignment.  They
 280    are used to propagate subaccesses from rhs to lhs as long as they don't
 281    conflict with what is already there.  */
 282 struct assign_link
 283 {
 284   struct access *lacc, *racc;
 285   struct assign_link *next;
 286 };
 287
 288 /* Alloc pool for allocating assign link structures.  */
 289 static object_allocator<assign_link> assign_link_pool ("SRA links");
 290
 291 /* Base (tree) -> Vector (vec<access_p> *) map.  */
 292 static hash_map<tree, auto_vec<access_p> > *base_access_vec;
 293
 294 /* Candidate hash table helpers.  */
 295
 296 struct uid_decl_hasher : nofree_ptr_hash <tree_node>
 297 {
 298   static inline hashval_t hash (const tree_node *);
 299   static inline bool equal (const tree_node *, const tree_node *);
 300 };
 301
 302 /* Hash a tree in a uid_decl_map.  */
 303
 304 inline hashval_t
 305 uid_decl_hasher::hash (const tree_node *item)
 306 {
 307   return item->decl_minimal.uid;
 308 }
 309
 310 /* Return true if the DECL_UID in both trees are equal.  */
 311
 312 inline bool
 313 uid_decl_hasher::equal (const tree_node *a, const tree_node *b)
 314 {
 315   return (a->decl_minimal.uid == b->decl_minimal.uid);
 316 }
 317
 318 /* Set of candidates.  */
 319 static bitmap candidate_bitmap;
 320 static hash_table<uid_decl_hasher> *candidates;
 321
 322 /* For a candidate UID return the candidates decl.  */
 323
 324 static inline tree
 325 candidate (unsigned uid)
 326 {
 327  tree_node t;
 328  t.decl_minimal.uid = uid;
 329  return candidates->find_with_hash (&t, static_cast <hashval_t> (uid));
 330 }
 331
 332 /* Bitmap of candidates which we should try to entirely scalarize away and
 333    those which cannot be (because they are and need be used as a whole).  */
 334 static bitmap should_scalarize_away_bitmap, cannot_scalarize_away_bitmap;
 335
 336 /* Bitmap of candidates in the constant pool, which cannot be scalarized
 337    because this would produce non-constant expressions (e.g. Ada).  */
 338 static bitmap disqualified_constants;
 339
 340 /* Obstack for creation of fancy names.  */
 341 static struct obstack name_obstack;
 342
 343 /* Head of a linked list of accesses that need to have its subaccesses
 344    propagated to their assignment counterparts. */
 345 static struct access *work_queue_head;
 346
 347 /* Number of parameters of the analyzed function when doing early ipa SRA.  */
 348 static int func_param_count;
 349
 350 /* scan_function sets the following to true if it encounters a call to
 351    __builtin_apply_args.  */
 352 static bool encountered_apply_args;
 353
 354 /* Set by scan_function when it finds a recursive call.  */
 355 static bool encountered_recursive_call;
 356
 357 /* Set by scan_function when it finds a recursive call with less actual
 358    arguments than formal parameters..  */
 359 static bool encountered_unchangable_recursive_call;
 360
 361 /* This is a table in which for each basic block and parameter there is a
 362    distance (offset + size) in that parameter which is dereferenced and
 363    accessed in that BB.  */
 364 static HOST_WIDE_INT *bb_dereferences;
 365 /* Bitmap of BBs that can cause the function to "stop" progressing by
 366    returning, throwing externally, looping infinitely or calling a function
 367    which might abort etc.. */
 368 static bitmap final_bbs;
 369
 370 /* Representative of no accesses at all. */
 371 static struct access  no_accesses_representant;
 372
 373 /* Predicate to test the special value.  */
 374
 375 static inline bool
 376 no_accesses_p (struct access *access)
 377 {
 378   return access == &no_accesses_representant;
 379 }
 380
 381 /* Dump contents of ACCESS to file F in a human friendly way.  If GRP is true,
 382    representative fields are dumped, otherwise those which only describe the
 383    individual access are.  */
 384
 385 static struct
 386 {
 387   /* Number of processed aggregates is readily available in
 388      analyze_all_variable_accesses and so is not stored here.  */
 389
 390   /* Number of created scalar replacements.  */
 391   int replacements;
 392
 393   /* Number of times sra_modify_expr or sra_modify_assign themselves changed an
 394      expression.  */
 395   int exprs;
 396
 397   /* Number of statements created by generate_subtree_copies.  */
 398   int subtree_copies;
 399
 400   /* Number of statements created by load_assign_lhs_subreplacements.  */
 401   int subreplacements;
 402
 403   /* Number of times sra_modify_assign has deleted a statement.  */
 404   int deleted;
 405
 406   /* Number of times sra_modify_assign has to deal with subaccesses of LHS and
 407      RHS reparately due to type conversions or nonexistent matching
 408      references.  */
 409   int separate_lhs_rhs_handling;
 410
 411   /* Number of parameters that were removed because they were unused.  */
 412   int deleted_unused_parameters;
 413
 414   /* Number of scalars passed as parameters by reference that have been
 415      converted to be passed by value.  */
 416   int scalar_by_ref_to_by_val;
 417
 418   /* Number of aggregate parameters that were replaced by one or more of their
 419      components.  */
 420   int aggregate_params_reduced;
 421
 422   /* Numbber of components created when splitting aggregate parameters.  */
 423   int param_reductions_created;
 424 } sra_stats;
 425
 426 static void
 427 dump_access (FILE *f, struct access *access, bool grp)
 428 {
 429   fprintf (f, "access { ");
 430   fprintf (f, "base = (%d)'", DECL_UID (access->base));
 431   print_generic_expr (f, access->base);
 432   fprintf (f, "', offset = " HOST_WIDE_INT_PRINT_DEC, access->offset);
 433   fprintf (f, ", size = " HOST_WIDE_INT_PRINT_DEC, access->size);
 434   fprintf (f, ", expr = ");
 435   print_generic_expr (f, access->expr);
 436   fprintf (f, ", type = ");
 437   print_generic_expr (f, access->type);
 438   fprintf (f, ", non_addressable = %d, reverse = %d",
 439            access->non_addressable, access->reverse);
 440   if (grp)
 441     fprintf (f, ", grp_read = %d, grp_write = %d, grp_assignment_read = %d, "
 442              "grp_assignment_write = %d, grp_scalar_read = %d, "
 443              "grp_scalar_write = %d, grp_total_scalarization = %d, "
 444              "grp_hint = %d, grp_covered = %d, "
 445              "grp_unscalarizable_region = %d, grp_unscalarized_data = %d, "
 446              "grp_partial_lhs = %d, grp_to_be_replaced = %d, "
 447              "grp_to_be_debug_replaced = %d, grp_maybe_modified = %d, "
 448              "grp_not_necessarilly_dereferenced = %d\n",
 449              access->grp_read, access->grp_write, access->grp_assignment_read,
 450              access->grp_assignment_write, access->grp_scalar_read,
 451              access->grp_scalar_write, access->grp_total_scalarization,
 452              access->grp_hint, access->grp_covered,
 453              access->grp_unscalarizable_region, access->grp_unscalarized_data,
 454              access->grp_partial_lhs, access->grp_to_be_replaced,
 455              access->grp_to_be_debug_replaced, access->grp_maybe_modified,
 456              access->grp_not_necessarilly_dereferenced);
 457   else
 458     fprintf (f, ", write = %d, grp_total_scalarization = %d, "
 459              "grp_partial_lhs = %d\n",
 460              access->write, access->grp_total_scalarization,
 461              access->grp_partial_lhs);
 462 }
 463
 464 /* Dump a subtree rooted in ACCESS to file F, indent by LEVEL.  */
 465
 466 static void
 467 dump_access_tree_1 (FILE *f, struct access *access, int level)
 468 {
 469   do
 470     {
 471       int i;
 472
 473       for (i = 0; i < level; i++)
 474         fputs ("* ", f);
 475
 476       dump_access (f, access, true);
 477
 478       if (access->first_child)
 479         dump_access_tree_1 (f, access->first_child, level + 1);
 480
 481       access = access->next_sibling;
 482     }
 483   while (access);
 484 }
 485
 486 /* Dump all access trees for a variable, given the pointer to the first root in
 487    ACCESS.  */
 488
 489 static void
 490 dump_access_tree (FILE *f, struct access *access)
 491 {
 492   for (; access; access = access->next_grp)
 493     dump_access_tree_1 (f, access, 0);
 494 }
 495
 496 /* Return true iff ACC is non-NULL and has subaccesses.  */
 497
 498 static inline bool
 499 access_has_children_p (struct access *acc)
 500 {
 501   return acc && acc->first_child;
 502 }
 503
 504 /* Return true iff ACC is (partly) covered by at least one replacement.  */
 505
 506 static bool
 507 access_has_replacements_p (struct access *acc)
 508 {
 509   struct access *child;
 510   if (acc->grp_to_be_replaced)
 511     return true;
 512   for (child = acc->first_child; child; child = child->next_sibling)
 513     if (access_has_replacements_p (child))
 514       return true;
 515   return false;
 516 }
 517
 518 /* Return a vector of pointers to accesses for the variable given in BASE or
 519    NULL if there is none.  */
 520
 521 static vec<access_p> *
 522 get_base_access_vector (tree base)
 523 {
 524   return base_access_vec->get (base);
 525 }
 526
 527 /* Find an access with required OFFSET and SIZE in a subtree of accesses rooted
 528    in ACCESS.  Return NULL if it cannot be found.  */
 529
 530 static struct access *
 531 find_access_in_subtree (struct access *access, HOST_WIDE_INT offset,
 532                         HOST_WIDE_INT size)
 533 {
 534   while (access && (access->offset != offset || access->size != size))
 535     {
 536       struct access *child = access->first_child;
 537
 538       while (child && (child->offset + child->size <= offset))
 539         child = child->next_sibling;
 540       access = child;
 541     }
 542
 543   return access;
 544 }
 545
 546 /* Return the first group representative for DECL or NULL if none exists.  */
 547
 548 static struct access *
 549 get_first_repr_for_decl (tree base)
 550 {
 551   vec<access_p> *access_vec;
 552
 553   access_vec = get_base_access_vector (base);
 554   if (!access_vec)
 555     return NULL;
 556
 557   return (*access_vec)[0];
 558 }
 559
 560 /* Find an access representative for the variable BASE and given OFFSET and
 561    SIZE.  Requires that access trees have already been built.  Return NULL if
 562    it cannot be found.  */
 563
 564 static struct access *
 565 get_var_base_offset_size_access (tree base, HOST_WIDE_INT offset,
 566                                  HOST_WIDE_INT size)
 567 {
 568   struct access *access;
 569
 570   access = get_first_repr_for_decl (base);
 571   while (access && (access->offset + access->size <= offset))
 572     access = access->next_grp;
 573   if (!access)
 574     return NULL;
 575
 576   return find_access_in_subtree (access, offset, size);
 577 }
 578
 579 /* Add LINK to the linked list of assign links of RACC.  */
 580 static void
 581 add_link_to_rhs (struct access *racc, struct assign_link *link)
 582 {
 583   gcc_assert (link->racc == racc);
 584
 585   if (!racc->first_link)
 586     {
 587       gcc_assert (!racc->last_link);
 588       racc->first_link = link;
 589     }
 590   else
 591     racc->last_link->next = link;
 592
 593   racc->last_link = link;
 594   link->next = NULL;
 595 }
 596
 597 /* Move all link structures in their linked list in OLD_RACC to the linked list
 598    in NEW_RACC.  */
 599 static void
 600 relink_to_new_repr (struct access *new_racc, struct access *old_racc)
 601 {
 602   if (!old_racc->first_link)
 603     {
 604       gcc_assert (!old_racc->last_link);
 605       return;
 606     }
 607
 608   if (new_racc->first_link)
 609     {
 610       gcc_assert (!new_racc->last_link->next);
 611       gcc_assert (!old_racc->last_link || !old_racc->last_link->next);
 612
 613       new_racc->last_link->next = old_racc->first_link;
 614       new_racc->last_link = old_racc->last_link;
 615     }
 616   else
 617     {
 618       gcc_assert (!new_racc->last_link);
 619
 620       new_racc->first_link = old_racc->first_link;
 621       new_racc->last_link = old_racc->last_link;
 622     }
 623   old_racc->first_link = old_racc->last_link = NULL;
 624 }
 625
 626 /* Add ACCESS to the work queue (which is actually a stack).  */
 627
 628 static void
 629 add_access_to_work_queue (struct access *access)
 630 {
 631   if (access->first_link && !access->grp_queued)
 632     {
 633       gcc_assert (!access->next_queued);
 634       access->next_queued = work_queue_head;
 635       access->grp_queued = 1;
 636       work_queue_head = access;
 637     }
 638 }
 639
 640 /* Pop an access from the work queue, and return it, assuming there is one.  */
 641
 642 static struct access *
 643 pop_access_from_work_queue (void)
 644 {
 645   struct access *access = work_queue_head;
 646
 647   work_queue_head = access->next_queued;
 648   access->next_queued = NULL;
 649   access->grp_queued = 0;
 650   return access;
 651 }
 652
 653
 654 /* Allocate necessary structures.  */
 655
 656 static void
 657 sra_initialize (void)
 658 {
 659   candidate_bitmap = BITMAP_ALLOC (NULL);
 660   candidates = new hash_table<uid_decl_hasher>
 661     (vec_safe_length (cfun->local_decls) / 2);
 662   should_scalarize_away_bitmap = BITMAP_ALLOC (NULL);
 663   cannot_scalarize_away_bitmap = BITMAP_ALLOC (NULL);
 664   disqualified_constants = BITMAP_ALLOC (NULL);
 665   gcc_obstack_init (&name_obstack);
 666   base_access_vec = new hash_map<tree, auto_vec<access_p> >;
 667   memset (&sra_stats, 0, sizeof (sra_stats));
 668   encountered_apply_args = false;
 669   encountered_recursive_call = false;
 670   encountered_unchangable_recursive_call = false;
 671 }
 672
 673 /* Deallocate all general structures.  */
 674
 675 static void
 676 sra_deinitialize (void)
 677 {
 678   BITMAP_FREE (candidate_bitmap);
 679   delete candidates;
 680   candidates = NULL;
 681   BITMAP_FREE (should_scalarize_away_bitmap);
 682   BITMAP_FREE (cannot_scalarize_away_bitmap);
 683   BITMAP_FREE (disqualified_constants);
 684   access_pool.release ();
 685   assign_link_pool.release ();
 686   obstack_free (&name_obstack, NULL);
 687
 688   delete base_access_vec;
 689 }
 690
 691 /* Return true if DECL is a VAR_DECL in the constant pool, false otherwise.  */
 692
 693 static bool constant_decl_p (tree decl)
 694 {
 695   return VAR_P (decl) && DECL_IN_CONSTANT_POOL (decl);
 696 }
 697
 698 /* Remove DECL from candidates for SRA and write REASON to the dump file if
 699    there is one.  */
 700
 701 static void
 702 disqualify_candidate (tree decl, const char *reason)
 703 {
 704   if (bitmap_clear_bit (candidate_bitmap, DECL_UID (decl)))
 705     candidates->remove_elt_with_hash (decl, DECL_UID (decl));
 706   if (constant_decl_p (decl))
 707     bitmap_set_bit (disqualified_constants, DECL_UID (decl));
 708
 709   if (dump_file && (dump_flags & TDF_DETAILS))
 710     {
 711       fprintf (dump_file, "! Disqualifying ");
 712       print_generic_expr (dump_file, decl);
 713       fprintf (dump_file, " - %s\n", reason);
 714     }
 715 }
 716
 717 /* Return true iff the type contains a field or an element which does not allow
 718    scalarization.  */
 719
 720 static bool
 721 type_internals_preclude_sra_p (tree type, const char **msg)
 722 {
 723   tree fld;
 724   tree et;
 725
 726   switch (TREE_CODE (type))
 727     {
 728     case RECORD_TYPE:
 729     case UNION_TYPE:
 730     case QUAL_UNION_TYPE:
 731       for (fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld))
 732         if (TREE_CODE (fld) == FIELD_DECL)
 733           {
 734             tree ft = TREE_TYPE (fld);
 735
 736             if (TREE_THIS_VOLATILE (fld))
 737               {
 738                 *msg = "volatile structure field";
 739                 return true;
 740               }
 741             if (!DECL_FIELD_OFFSET (fld))
 742               {
 743                 *msg = "no structure field offset";
 744                 return true;
 745               }
 746             if (!DECL_SIZE (fld))
 747               {
 748                 *msg = "zero structure field size";
 749                 return true;
 750               }
 751             if (!tree_fits_uhwi_p (DECL_FIELD_OFFSET (fld)))
 752               {
 753                 *msg = "structure field offset not fixed";
 754                 return true;
 755               }
 756             if (!tree_fits_uhwi_p (DECL_SIZE (fld)))
 757               {
 758                 *msg = "structure field size not fixed";
 759                 return true;
 760               }
 761             if (!tree_fits_shwi_p (bit_position (fld)))
 762               {
 763                 *msg = "structure field size too big";
 764                 return true;
 765               }
 766             if (AGGREGATE_TYPE_P (ft)
 767                     && int_bit_position (fld) % BITS_PER_UNIT != 0)
 768               {
 769                 *msg = "structure field is bit field";
 770                 return true;
 771               }
 772
 773             if (AGGREGATE_TYPE_P (ft) && type_internals_preclude_sra_p (ft, msg))
 774               return true;
 775           }
 776
 777       return false;
 778
 779     case ARRAY_TYPE:
 780       et = TREE_TYPE (type);
 781
 782       if (TYPE_VOLATILE (et))
 783         {
 784           *msg = "element type is volatile";
 785           return true;
 786         }
 787
 788       if (AGGREGATE_TYPE_P (et) && type_internals_preclude_sra_p (et, msg))
 789         return true;
 790
 791       return false;
 792
 793     default:
 794       return false;
 795     }
 796 }
 797
 798 /* If T is an SSA_NAME, return NULL if it is not a default def or return its
 799    base variable if it is.  Return T if it is not an SSA_NAME.  */
 800
 801 static tree
 802 get_ssa_base_param (tree t)
 803 {
 804   if (TREE_CODE (t) == SSA_NAME)
 805     {
 806       if (SSA_NAME_IS_DEFAULT_DEF (t))
 807         return SSA_NAME_VAR (t);
 808       else
 809         return NULL_TREE;
 810     }
 811   return t;
 812 }
 813
 814 /* Mark a dereference of BASE of distance DIST in a basic block tht STMT
 815    belongs to, unless the BB has already been marked as a potentially
 816    final.  */
 817
 818 static void
 819 mark_parm_dereference (tree base, HOST_WIDE_INT dist, gimple *stmt)
 820 {
 821   basic_block bb = gimple_bb (stmt);
 822   int idx, parm_index = 0;
 823   tree parm;
 824
 825   if (bitmap_bit_p (final_bbs, bb->index))
 826     return;
 827
 828   for (parm = DECL_ARGUMENTS (current_function_decl);
 829        parm && parm != base;
 830        parm = DECL_CHAIN (parm))
 831     parm_index++;
 832
 833   gcc_assert (parm_index < func_param_count);
 834
 835   idx = bb->index * func_param_count + parm_index;
 836   if (bb_dereferences[idx] < dist)
 837     bb_dereferences[idx] = dist;
 838 }
 839
 840 /* Allocate an access structure for BASE, OFFSET and SIZE, clear it, fill in
 841    the three fields.  Also add it to the vector of accesses corresponding to
 842    the base.  Finally, return the new access.  */
 843
 844 static struct access *
 845 create_access_1 (tree base, HOST_WIDE_INT offset, HOST_WIDE_INT size)
 846 {
 847   struct access *access = access_pool.allocate ();
 848
 849   memset (access, 0, sizeof (struct access));
 850   access->base = base;
 851   access->offset = offset;
 852   access->size = size;
 853
 854   base_access_vec->get_or_insert (base).safe_push (access);
 855
 856   return access;
 857 }
 858
 859 static bool maybe_add_sra_candidate (tree);
 860
 861 /* Create and insert access for EXPR. Return created access, or NULL if it is
 862    not possible.  Also scan for uses of constant pool as we go along and add
 863    to candidates.  */
 864
 865 static struct access *
 866 create_access (tree expr, gimple *stmt, bool write)
 867 {
 868   struct access *access;
 869   poly_int64 poffset, psize, pmax_size;
 870   HOST_WIDE_INT offset, size, max_size;
 871   tree base = expr;
 872   bool reverse, ptr, unscalarizable_region = false;
 873
 874   base = get_ref_base_and_extent (expr, &poffset, &psize, &pmax_size,
 875                                   &reverse);
 876   if (!poffset.is_constant (&offset)
 877       || !psize.is_constant (&size)
 878       || !pmax_size.is_constant (&max_size))
 879     {
 880       disqualify_candidate (base, "Encountered a polynomial-sized access.");
 881       return NULL;
 882     }
 883
 884   if (sra_mode == SRA_MODE_EARLY_IPA
 885       && TREE_CODE (base) == MEM_REF)
 886     {
 887       base = get_ssa_base_param (TREE_OPERAND (base, 0));
 888       if (!base)
 889         return NULL;
 890       ptr = true;
 891     }
 892   else
 893     ptr = false;
 894
 895   /* For constant-pool entries, check we can substitute the constant value.  */
 896   if (constant_decl_p (base)
 897       && (sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA))
 898     {
 899       gcc_assert (!bitmap_bit_p (disqualified_constants, DECL_UID (base)));
 900       if (expr != base
 901           && !is_gimple_reg_type (TREE_TYPE (expr))
 902           && dump_file && (dump_flags & TDF_DETAILS))
 903         {
 904           /* This occurs in Ada with accesses to ARRAY_RANGE_REFs,
 905              and elements of multidimensional arrays (which are
 906              multi-element arrays in their own right).  */
 907           fprintf (dump_file, "Allowing non-reg-type load of part"
 908                               " of constant-pool entry: ");
 909           print_generic_expr (dump_file, expr);
 910         }
 911       maybe_add_sra_candidate (base);
 912     }
 913
 914   if (!DECL_P (base) || !bitmap_bit_p (candidate_bitmap, DECL_UID (base)))
 915     return NULL;
 916
 917   if (sra_mode == SRA_MODE_EARLY_IPA)
 918     {
 919       if (size < 0 || size != max_size)
 920         {
 921           disqualify_candidate (base, "Encountered a variable sized access.");
 922           return NULL;
 923         }
 924       if (TREE_CODE (expr) == COMPONENT_REF
 925           && DECL_BIT_FIELD (TREE_OPERAND (expr, 1)))
 926         {
 927           disqualify_candidate (base, "Encountered a bit-field access.");
 928           return NULL;
 929         }
 930       gcc_checking_assert ((offset % BITS_PER_UNIT) == 0);
 931
 932       if (ptr)
 933         mark_parm_dereference (base, offset + size, stmt);
 934     }
 935   else
 936     {
 937       if (size != max_size)
 938         {
 939           size = max_size;
 940           unscalarizable_region = true;
 941         }
 942       if (size < 0)
 943         {
 944           disqualify_candidate (base, "Encountered an unconstrained access.");
 945           return NULL;
 946         }
 947     }
 948
 949   access = create_access_1 (base, offset, size);
 950   access->expr = expr;
 951   access->type = TREE_TYPE (expr);
 952   access->write = write;
 953   access->grp_unscalarizable_region = unscalarizable_region;
 954   access->stmt = stmt;
 955   access->reverse = reverse;
 956
 957   if (TREE_CODE (expr) == COMPONENT_REF
 958       && DECL_NONADDRESSABLE_P (TREE_OPERAND (expr, 1)))
 959     access->non_addressable = 1;
 960
 961   return access;
 962 }
 963
 964
 965 /* Return true iff TYPE is scalarizable - i.e. a RECORD_TYPE or fixed-length
 966    ARRAY_TYPE with fields that are either of gimple register types (excluding
 967    bit-fields) or (recursively) scalarizable types.  CONST_DECL must be true if
 968    we are considering a decl from constant pool.  If it is false, char arrays
 969    will be refused.  */
 970
 971 static bool
 972 scalarizable_type_p (tree type, bool const_decl)
 973 {
 974   gcc_assert (!is_gimple_reg_type (type));
 975   if (type_contains_placeholder_p (type))
 976     return false;
 977
 978   switch (TREE_CODE (type))
 979   {
 980   case RECORD_TYPE:
 981     for (tree fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld))
 982       if (TREE_CODE (fld) == FIELD_DECL)
 983         {
 984           tree ft = TREE_TYPE (fld);
 985
 986           if (DECL_BIT_FIELD (fld))
 987             return false;
 988
 989           if (!is_gimple_reg_type (ft)
 990               && !scalarizable_type_p (ft, const_decl))
 991             return false;
 992         }
 993
 994     return true;
 995
 996   case ARRAY_TYPE:
 997     {
 998       HOST_WIDE_INT min_elem_size;
 999       if (const_decl)
1000         min_elem_size = 0;
1001       else
1002         min_elem_size = BITS_PER_UNIT;
1003
1004       if (TYPE_DOMAIN (type) == NULL_TREE
1005           || !tree_fits_shwi_p (TYPE_SIZE (type))
1006           || !tree_fits_shwi_p (TYPE_SIZE (TREE_TYPE (type)))
1007           || (tree_to_shwi (TYPE_SIZE (TREE_TYPE (type))) <= min_elem_size)
1008           || !tree_fits_shwi_p (TYPE_MIN_VALUE (TYPE_DOMAIN (type))))
1009         return false;
1010       if (tree_to_shwi (TYPE_SIZE (type)) == 0
1011           && TYPE_MAX_VALUE (TYPE_DOMAIN (type)) == NULL_TREE)
1012         /* Zero-element array, should not prevent scalarization.  */
1013         ;
1014       else if ((tree_to_shwi (TYPE_SIZE (type)) <= 0)
1015                || !tree_fits_shwi_p (TYPE_MAX_VALUE (TYPE_DOMAIN (type))))
1016         /* Variable-length array, do not allow scalarization.  */
1017         return false;
1018
1019       tree elem = TREE_TYPE (type);
1020       if (!is_gimple_reg_type (elem)
1021           && !scalarizable_type_p (elem, const_decl))
1022         return false;
1023       return true;
1024     }
1025   default:
1026     return false;
1027   }
1028 }
1029
1030 static void scalarize_elem (tree, HOST_WIDE_INT, HOST_WIDE_INT, bool, tree, tree);
1031
1032 /* Create total_scalarization accesses for all scalar fields of a member
1033    of type DECL_TYPE conforming to scalarizable_type_p.  BASE
1034    must be the top-most VAR_DECL representing the variable; within that,
1035    OFFSET locates the member and REF must be the memory reference expression for
1036    the member.  */
1037
1038 static void
1039 completely_scalarize (tree base, tree decl_type, HOST_WIDE_INT offset, tree ref)
1040 {
1041   switch (TREE_CODE (decl_type))
1042     {
1043     case RECORD_TYPE:
1044       for (tree fld = TYPE_FIELDS (decl_type); fld; fld = DECL_CHAIN (fld))
1045         if (TREE_CODE (fld) == FIELD_DECL)
1046           {
1047             HOST_WIDE_INT pos = offset + int_bit_position (fld);
1048             tree ft = TREE_TYPE (fld);
1049             tree nref = build3 (COMPONENT_REF, ft, ref, fld, NULL_TREE);
1050
1051             scalarize_elem (base, pos, tree_to_uhwi (DECL_SIZE (fld)),
1052                             TYPE_REVERSE_STORAGE_ORDER (decl_type),
1053                             nref, ft);
1054           }
1055       break;
1056     case ARRAY_TYPE:
1057       {
1058         tree elemtype = TREE_TYPE (decl_type);
1059         tree elem_size = TYPE_SIZE (elemtype);
1060         gcc_assert (elem_size && tree_fits_shwi_p (elem_size));
1061         HOST_WIDE_INT el_size = tree_to_shwi (elem_size);
1062         gcc_assert (el_size > 0);
1063
1064         tree minidx = TYPE_MIN_VALUE (TYPE_DOMAIN (decl_type));
1065         gcc_assert (TREE_CODE (minidx) == INTEGER_CST);
1066         tree maxidx = TYPE_MAX_VALUE (TYPE_DOMAIN (decl_type));
1067         /* Skip (some) zero-length arrays; others have MAXIDX == MINIDX - 1.  */
1068         if (maxidx)
1069           {
1070             gcc_assert (TREE_CODE (maxidx) == INTEGER_CST);
1071             tree domain = TYPE_DOMAIN (decl_type);
1072             /* MINIDX and MAXIDX are inclusive, and must be interpreted in
1073                DOMAIN (e.g. signed int, whereas min/max may be size_int).  */
1074             offset_int idx = wi::to_offset (minidx);
1075             offset_int max = wi::to_offset (maxidx);
1076             if (!TYPE_UNSIGNED (domain))
1077               {
1078                 idx = wi::sext (idx, TYPE_PRECISION (domain));
1079                 max = wi::sext (max, TYPE_PRECISION (domain));
1080               }
1081             for (int el_off = offset; idx <= max; ++idx)
1082               {
1083                 tree nref = build4 (ARRAY_REF, elemtype,
1084                                     ref,
1085                                     wide_int_to_tree (domain, idx),
1086                                     NULL_TREE, NULL_TREE);
1087                 scalarize_elem (base, el_off, el_size,
1088                                 TYPE_REVERSE_STORAGE_ORDER (decl_type),
1089                                 nref, elemtype);
1090                 el_off += el_size;
1091               }
1092           }
1093       }
1094       break;
1095     default:
1096       gcc_unreachable ();
1097     }
1098 }
1099
1100 /* Create total_scalarization accesses for a member of type TYPE, which must
1101    satisfy either is_gimple_reg_type or scalarizable_type_p.  BASE must be the
1102    top-most VAR_DECL representing the variable; within that, POS and SIZE locate
1103    the member, REVERSE gives its torage order. and REF must be the reference
1104    expression for it.  */
1105
1106 static void
1107 scalarize_elem (tree base, HOST_WIDE_INT pos, HOST_WIDE_INT size, bool reverse,
1108                 tree ref, tree type)
1109 {
1110   if (is_gimple_reg_type (type))
1111   {
1112     struct access *access = create_access_1 (base, pos, size);
1113     access->expr = ref;
1114     access->type = type;
1115     access->grp_total_scalarization = 1;
1116     access->reverse = reverse;
1117     /* Accesses for intraprocedural SRA can have their stmt NULL.  */
1118   }
1119   else
1120     completely_scalarize (base, type, pos, ref);
1121 }
1122
1123 /* Create a total_scalarization access for VAR as a whole.  VAR must be of a
1124    RECORD_TYPE or ARRAY_TYPE conforming to scalarizable_type_p.  */
1125
1126 static void
1127 create_total_scalarization_access (tree var)
1128 {
1129   HOST_WIDE_INT size = tree_to_uhwi (DECL_SIZE (var));
1130   struct access *access;
1131
1132   access = create_access_1 (var, 0, size);
1133   access->expr = var;
1134   access->type = TREE_TYPE (var);
1135   access->grp_total_scalarization = 1;
1136 }
1137
1138 /* Return true if REF has an VIEW_CONVERT_EXPR somewhere in it.  */
1139
1140 static inline bool
1141 contains_view_convert_expr_p (const_tree ref)
1142 {
1143   while (handled_component_p (ref))
1144     {
1145       if (TREE_CODE (ref) == VIEW_CONVERT_EXPR)
1146         return true;
1147       ref = TREE_OPERAND (ref, 0);
1148     }
1149
1150   return false;
1151 }
1152
1153 /* Return true if REF contains a VIEW_CONVERT_EXPR or a MEM_REF that performs
1154    type conversion or a COMPONENT_REF with a bit-field field declaration.  */
1155
1156 static bool
1157 contains_vce_or_bfcref_p (const_tree ref)
1158 {
1159   while (handled_component_p (ref))
1160     {
1161       if (TREE_CODE (ref) == VIEW_CONVERT_EXPR
1162           || (TREE_CODE (ref) == COMPONENT_REF
1163               && DECL_BIT_FIELD (TREE_OPERAND (ref, 1))))
1164         return true;
1165       ref = TREE_OPERAND (ref, 0);
1166     }
1167
1168   if (TREE_CODE (ref) != MEM_REF
1169       || TREE_CODE (TREE_OPERAND (ref, 0)) != ADDR_EXPR)
1170     return false;
1171
1172   tree mem = TREE_OPERAND (TREE_OPERAND (ref, 0), 0);
1173   if (TYPE_MAIN_VARIANT (TREE_TYPE (ref))
1174       != TYPE_MAIN_VARIANT (TREE_TYPE (mem)))
1175     return true;
1176
1177   return false;
1178 }
1179
1180 /* Search the given tree for a declaration by skipping handled components and
1181    exclude it from the candidates.  */
1182
1183 static void
1184 disqualify_base_of_expr (tree t, const char *reason)
1185 {
1186   t = get_base_address (t);
1187   if (sra_mode == SRA_MODE_EARLY_IPA
1188       && TREE_CODE (t) == MEM_REF)
1189     t = get_ssa_base_param (TREE_OPERAND (t, 0));
1190
1191   if (t && DECL_P (t))
1192     disqualify_candidate (t, reason);
1193 }
1194
1195 /* Scan expression EXPR and create access structures for all accesses to
1196    candidates for scalarization.  Return the created access or NULL if none is
1197    created.  */
1198
1199 static struct access *
1200 build_access_from_expr_1 (tree expr, gimple *stmt, bool write)
1201 {
1202   struct access *ret = NULL;
1203   bool partial_ref;
1204
1205   if (TREE_CODE (expr) == BIT_FIELD_REF
1206       || TREE_CODE (expr) == IMAGPART_EXPR
1207       || TREE_CODE (expr) == REALPART_EXPR)
1208     {
1209       expr = TREE_OPERAND (expr, 0);
1210       partial_ref = true;
1211     }
1212   else
1213     partial_ref = false;
1214
1215   if (storage_order_barrier_p (expr))
1216     {
1217       disqualify_base_of_expr (expr, "storage order barrier.");
1218       return NULL;
1219     }
1220
1221   /* We need to dive through V_C_Es in order to get the size of its parameter
1222      and not the result type.  Ada produces such statements.  We are also
1223      capable of handling the topmost V_C_E but not any of those buried in other
1224      handled components.  */
1225   if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
1226     expr = TREE_OPERAND (expr, 0);
1227
1228   if (contains_view_convert_expr_p (expr))
1229     {
1230       disqualify_base_of_expr (expr, "V_C_E under a different handled "
1231                                "component.");
1232       return NULL;
1233     }
1234   if (TREE_THIS_VOLATILE (expr))
1235     {
1236       disqualify_base_of_expr (expr, "part of a volatile reference.");
1237       return NULL;
1238     }
1239
1240   switch (TREE_CODE (expr))
1241     {
1242     case MEM_REF:
1243       if (TREE_CODE (TREE_OPERAND (expr, 0)) != ADDR_EXPR
1244           && sra_mode != SRA_MODE_EARLY_IPA)
1245         return NULL;
1246       /* fall through */
1247     case VAR_DECL:
1248     case PARM_DECL:
1249     case RESULT_DECL:
1250     case COMPONENT_REF:
1251     case ARRAY_REF:
1252     case ARRAY_RANGE_REF:
1253       ret = create_access (expr, stmt, write);
1254       break;
1255
1256     default:
1257       break;
1258     }
1259
1260   if (write && partial_ref && ret)
1261     ret->grp_partial_lhs = 1;
1262
1263   return ret;
1264 }
1265
1266 /* Scan expression EXPR and create access structures for all accesses to
1267    candidates for scalarization.  Return true if any access has been inserted.
1268    STMT must be the statement from which the expression is taken, WRITE must be
1269    true if the expression is a store and false otherwise. */
1270
1271 static bool
1272 build_access_from_expr (tree expr, gimple *stmt, bool write)
1273 {
1274   struct access *access;
1275
1276   access = build_access_from_expr_1 (expr, stmt, write);
1277   if (access)
1278     {
1279       /* This means the aggregate is accesses as a whole in a way other than an
1280          assign statement and thus cannot be removed even if we had a scalar
1281          replacement for everything.  */
1282       if (cannot_scalarize_away_bitmap)
1283         bitmap_set_bit (cannot_scalarize_away_bitmap, DECL_UID (access->base));
1284       return true;
1285     }
1286   return false;
1287 }
1288
1289 /* Return the single non-EH successor edge of BB or NULL if there is none or
1290    more than one.  */
1291
1292 static edge
1293 single_non_eh_succ (basic_block bb)
1294 {
1295   edge e, res = NULL;
1296   edge_iterator ei;
1297
1298   FOR_EACH_EDGE (e, ei, bb->succs)
1299     if (!(e->flags & EDGE_EH))
1300       {
1301         if (res)
1302           return NULL;
1303         res = e;
1304       }
1305
1306   return res;
1307 }
1308
1309 /* Disqualify LHS and RHS for scalarization if STMT has to terminate its BB and
1310    there is no alternative spot where to put statements SRA might need to
1311    generate after it.  The spot we are looking for is an edge leading to a
1312    single non-EH successor, if it exists and is indeed single.  RHS may be
1313    NULL, in that case ignore it.  */
1314
1315 static bool
1316 disqualify_if_bad_bb_terminating_stmt (gimple *stmt, tree lhs, tree rhs)
1317 {
1318   if ((sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA)
1319       && stmt_ends_bb_p (stmt))
1320     {
1321       if (single_non_eh_succ (gimple_bb (stmt)))
1322         return false;
1323
1324       disqualify_base_of_expr (lhs, "LHS of a throwing stmt.");
1325       if (rhs)
1326         disqualify_base_of_expr (rhs, "RHS of a throwing stmt.");
1327       return true;
1328     }
1329   return false;
1330 }
1331
1332 /* Return true if the nature of BASE is such that it contains data even if
1333    there is no write to it in the function.  */
1334
1335 static bool
1336 comes_initialized_p (tree base)
1337 {
1338   return TREE_CODE (base) == PARM_DECL || constant_decl_p (base);
1339 }
1340
1341 /* Scan expressions occurring in STMT, create access structures for all accesses
1342    to candidates for scalarization and remove those candidates which occur in
1343    statements or expressions that prevent them from being split apart.  Return
1344    true if any access has been inserted.  */
1345
1346 static bool
1347 build_accesses_from_assign (gimple *stmt)
1348 {
1349   tree lhs, rhs;
1350   struct access *lacc, *racc;
1351
1352   if (!gimple_assign_single_p (stmt)
1353       /* Scope clobbers don't influence scalarization.  */
1354       || gimple_clobber_p (stmt))
1355     return false;
1356
1357   lhs = gimple_assign_lhs (stmt);
1358   rhs = gimple_assign_rhs1 (stmt);
1359
1360   if (disqualify_if_bad_bb_terminating_stmt (stmt, lhs, rhs))
1361     return false;
1362
1363   racc = build_access_from_expr_1 (rhs, stmt, false);
1364   lacc = build_access_from_expr_1 (lhs, stmt, true);
1365
1366   if (lacc)
1367     {
1368       lacc->grp_assignment_write = 1;
1369       if (storage_order_barrier_p (rhs))
1370         lacc->grp_unscalarizable_region = 1;
1371     }
1372
1373   if (racc)
1374     {
1375       racc->grp_assignment_read = 1;
1376       if (should_scalarize_away_bitmap && !gimple_has_volatile_ops (stmt)
1377           && !is_gimple_reg_type (racc->type))
1378         {
1379           if (contains_vce_or_bfcref_p (rhs))
1380             bitmap_set_bit (cannot_scalarize_away_bitmap,
1381                             DECL_UID (racc->base));
1382           else
1383             bitmap_set_bit (should_scalarize_away_bitmap,
1384                             DECL_UID (racc->base));
1385         }
1386       if (storage_order_barrier_p (lhs))
1387         racc->grp_unscalarizable_region = 1;
1388     }
1389
1390   if (lacc && racc
1391       && (sra_mode == SRA_MODE_EARLY_INTRA || sra_mode == SRA_MODE_INTRA)
1392       && !lacc->grp_unscalarizable_region
1393       && !racc->grp_unscalarizable_region
1394       && AGGREGATE_TYPE_P (TREE_TYPE (lhs))
1395       && lacc->size == racc->size
1396       && useless_type_conversion_p (lacc->type, racc->type))
1397     {
1398       struct assign_link *link;
1399
1400       link = assign_link_pool.allocate ();
1401       memset (link, 0, sizeof (struct assign_link));
1402
1403       link->lacc = lacc;
1404       link->racc = racc;
1405       add_link_to_rhs (racc, link);
1406       add_access_to_work_queue (racc);
1407
1408       /* Let's delay marking the areas as written until propagation of accesses
1409          across link, unless the nature of rhs tells us that its data comes
1410          from elsewhere.  */
1411       if (!comes_initialized_p (racc->base))
1412         lacc->write = false;
1413     }
1414
1415   return lacc || racc;
1416 }
1417
1418 /* Callback of walk_stmt_load_store_addr_ops visit_addr used to determine
1419    GIMPLE_ASM operands with memory constrains which cannot be scalarized.  */
1420
1421 static bool
1422 asm_visit_addr (gimple *, tree op, tree, void *)
1423 {
1424   op = get_base_address (op);
1425   if (op
1426       && DECL_P (op))
1427     disqualify_candidate (op, "Non-scalarizable GIMPLE_ASM operand.");
1428
1429   return false;
1430 }
1431
1432 /* Return true iff callsite CALL has at least as many actual arguments as there
1433    are formal parameters of the function currently processed by IPA-SRA and
1434    that their types match.  */
1435
1436 static inline bool
1437 callsite_arguments_match_p (gimple *call)
1438 {
1439   if (gimple_call_num_args (call) < (unsigned) func_param_count)
1440     return false;
1441
1442   tree parm;
1443   int i;
1444   for (parm = DECL_ARGUMENTS (current_function_decl), i = 0;
1445        parm;
1446        parm = DECL_CHAIN (parm), i++)
1447     {
1448       tree arg = gimple_call_arg (call, i);
1449       if (!useless_type_conversion_p (TREE_TYPE (parm), TREE_TYPE (arg)))
1450         return false;
1451     }
1452   return true;
1453 }
1454
1455 /* Scan function and look for interesting expressions and create access
1456    structures for them.  Return true iff any access is created.  */
1457
1458 static bool
1459 scan_function (void)
1460 {
1461   basic_block bb;
1462   bool ret = false;
1463
1464   FOR_EACH_BB_FN (bb, cfun)
1465     {
1466       gimple_stmt_iterator gsi;
1467       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
1468         {
1469           gimple *stmt = gsi_stmt (gsi);
1470           tree t;
1471           unsigned i;
1472
1473           if (final_bbs && stmt_can_throw_external (stmt))
1474             bitmap_set_bit (final_bbs, bb->index);
1475           switch (gimple_code (stmt))
1476             {
1477             case GIMPLE_RETURN:
1478               t = gimple_return_retval (as_a <greturn *> (stmt));
1479               if (t != NULL_TREE)
1480                 ret |= build_access_from_expr (t, stmt, false);
1481               if (final_bbs)
1482                 bitmap_set_bit (final_bbs, bb->index);
1483               break;
1484
1485             case GIMPLE_ASSIGN:
1486               ret |= build_accesses_from_assign (stmt);
1487               break;
1488
1489             case GIMPLE_CALL:
1490               for (i = 0; i < gimple_call_num_args (stmt); i++)
1491                 ret |= build_access_from_expr (gimple_call_arg (stmt, i),
1492                                                stmt, false);
1493
1494               if (sra_mode == SRA_MODE_EARLY_IPA)
1495                 {
1496                   tree dest = gimple_call_fndecl (stmt);
1497                   int flags = gimple_call_flags (stmt);
1498
1499                   if (dest)
1500                     {
1501                       if (DECL_BUILT_IN_CLASS (dest) == BUILT_IN_NORMAL
1502                           && DECL_FUNCTION_CODE (dest) == BUILT_IN_APPLY_ARGS)
1503                         encountered_apply_args = true;
1504                       if (recursive_call_p (current_function_decl, dest))
1505                         {
1506                           encountered_recursive_call = true;
1507                           if (!callsite_arguments_match_p (stmt))
1508                             encountered_unchangable_recursive_call = true;
1509                         }
1510                     }
1511
1512                   if (final_bbs
1513                       && (flags & (ECF_CONST | ECF_PURE)) == 0)
1514                     bitmap_set_bit (final_bbs, bb->index);
1515                 }
1516
1517               t = gimple_call_lhs (stmt);
1518               if (t && !disqualify_if_bad_bb_terminating_stmt (stmt, t, NULL))
1519                 ret |= build_access_from_expr (t, stmt, true);
1520               break;
1521
1522             case GIMPLE_ASM:
1523               {
1524                 gasm *asm_stmt = as_a <gasm *> (stmt);
1525                 walk_stmt_load_store_addr_ops (asm_stmt, NULL, NULL, NULL,
1526                                                asm_visit_addr);
1527                 if (final_bbs)
1528                   bitmap_set_bit (final_bbs, bb->index);
1529
1530                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
1531                   {
1532                     t = TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
1533                     ret |= build_access_from_expr (t, asm_stmt, false);
1534                   }
1535                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
1536                   {
1537                     t = TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
1538                     ret |= build_access_from_expr (t, asm_stmt, true);
1539                   }
1540               }
1541               break;
1542
1543             default:
1544               break;
1545             }
1546         }
1547     }
1548
1549   return ret;
1550 }
1551
1552 /* Helper of QSORT function. There are pointers to accesses in the array.  An
1553    access is considered smaller than another if it has smaller offset or if the
1554    offsets are the same but is size is bigger. */
1555
1556 static int
1557 compare_access_positions (const void *a, const void *b)
1558 {
1559   const access_p *fp1 = (const access_p *) a;
1560   const access_p *fp2 = (const access_p *) b;
1561   const access_p f1 = *fp1;
1562   const access_p f2 = *fp2;
1563
1564   if (f1->offset != f2->offset)
1565     return f1->offset < f2->offset ? -1 : 1;
1566
1567   if (f1->size == f2->size)
1568     {
1569       if (f1->type == f2->type)
1570         return 0;
1571       /* Put any non-aggregate type before any aggregate type.  */
1572       else if (!is_gimple_reg_type (f1->type)
1573           && is_gimple_reg_type (f2->type))
1574         return 1;
1575       else if (is_gimple_reg_type (f1->type)
1576                && !is_gimple_reg_type (f2->type))
1577         return -1;
1578       /* Put any complex or vector type before any other scalar type.  */
1579       else if (TREE_CODE (f1->type) != COMPLEX_TYPE
1580                && TREE_CODE (f1->type) != VECTOR_TYPE
1581                && (TREE_CODE (f2->type) == COMPLEX_TYPE
1582                    || TREE_CODE (f2->type) == VECTOR_TYPE))
1583         return 1;
1584       else if ((TREE_CODE (f1->type) == COMPLEX_TYPE
1585                 || TREE_CODE (f1->type) == VECTOR_TYPE)
1586                && TREE_CODE (f2->type) != COMPLEX_TYPE
1587                && TREE_CODE (f2->type) != VECTOR_TYPE)
1588         return -1;
1589       /* Put any integral type before any non-integral type.  When splicing, we
1590          make sure that those with insufficient precision and occupying the
1591          same space are not scalarized.  */
1592       else if (INTEGRAL_TYPE_P (f1->type)
1593                && !INTEGRAL_TYPE_P (f2->type))
1594         return -1;
1595       else if (!INTEGRAL_TYPE_P (f1->type)
1596                && INTEGRAL_TYPE_P (f2->type))
1597         return 1;
1598       /* Put the integral type with the bigger precision first.  */
1599       else if (INTEGRAL_TYPE_P (f1->type)
1600                && INTEGRAL_TYPE_P (f2->type)
1601                && (TYPE_PRECISION (f2->type) != TYPE_PRECISION (f1->type)))
1602         return TYPE_PRECISION (f2->type) - TYPE_PRECISION (f1->type);
1603       /* Stabilize the sort.  */
1604       return TYPE_UID (f1->type) - TYPE_UID (f2->type);
1605     }
1606
1607   /* We want the bigger accesses first, thus the opposite operator in the next
1608      line: */
1609   return f1->size > f2->size ? -1 : 1;
1610 }
1611
1612
1613 /* Append a name of the declaration to the name obstack.  A helper function for
1614    make_fancy_name.  */
1615
1616 static void
1617 make_fancy_decl_name (tree decl)
1618 {
1619   char buffer[32];
1620
1621   tree name = DECL_NAME (decl);
1622   if (name)
1623     obstack_grow (&name_obstack, IDENTIFIER_POINTER (name),
1624                   IDENTIFIER_LENGTH (name));
1625   else
1626     {
1627       sprintf (buffer, "D%u", DECL_UID (decl));
1628       obstack_grow (&name_obstack, buffer, strlen (buffer));
1629     }
1630 }
1631
1632 /* Helper for make_fancy_name.  */
1633
1634 static void
1635 make_fancy_name_1 (tree expr)
1636 {
1637   char buffer[32];
1638   tree index;
1639
1640   if (DECL_P (expr))
1641     {
1642       make_fancy_decl_name (expr);
1643       return;
1644     }
1645
1646   switch (TREE_CODE (expr))
1647     {
1648     case COMPONENT_REF:
1649       make_fancy_name_1 (TREE_OPERAND (expr, 0));
1650       obstack_1grow (&name_obstack, '$');
1651       make_fancy_decl_name (TREE_OPERAND (expr, 1));
1652       break;
1653
1654     case ARRAY_REF:
1655       make_fancy_name_1 (TREE_OPERAND (expr, 0));
1656       obstack_1grow (&name_obstack, '$');
1657       /* Arrays with only one element may not have a constant as their
1658          index. */
1659       index = TREE_OPERAND (expr, 1);
1660       if (TREE_CODE (index) != INTEGER_CST)
1661         break;
1662       sprintf (buffer, HOST_WIDE_INT_PRINT_DEC, TREE_INT_CST_LOW (index));
1663       obstack_grow (&name_obstack, buffer, strlen (buffer));
1664       break;
1665
1666     case ADDR_EXPR:
1667       make_fancy_name_1 (TREE_OPERAND (expr, 0));
1668       break;
1669
1670     case MEM_REF:
1671       make_fancy_name_1 (TREE_OPERAND (expr, 0));
1672       if (!integer_zerop (TREE_OPERAND (expr, 1)))
1673         {
1674           obstack_1grow (&name_obstack, '$');
1675           sprintf (buffer, HOST_WIDE_INT_PRINT_DEC,
1676                    TREE_INT_CST_LOW (TREE_OPERAND (expr, 1)));
1677           obstack_grow (&name_obstack, buffer, strlen (buffer));
1678         }
1679       break;
1680
1681     case BIT_FIELD_REF:
1682     case REALPART_EXPR:
1683     case IMAGPART_EXPR:
1684       gcc_unreachable ();       /* we treat these as scalars.  */
1685       break;
1686     default:
1687       break;
1688     }
1689 }
1690
1691 /* Create a human readable name for replacement variable of ACCESS.  */
1692
1693 static char *
1694 make_fancy_name (tree expr)
1695 {
1696   make_fancy_name_1 (expr);
1697   obstack_1grow (&name_obstack, '\0');
1698   return XOBFINISH (&name_obstack, char *);
1699 }
1700
1701 /* Construct a MEM_REF that would reference a part of aggregate BASE of type
1702    EXP_TYPE at the given OFFSET and with storage order REVERSE.  If BASE is
1703    something for which get_addr_base_and_unit_offset returns NULL, gsi must
1704    be non-NULL and is used to insert new statements either before or below
1705    the current one as specified by INSERT_AFTER.  This function is not capable
1706    of handling bitfields.  */
1707
1708 tree
1709 build_ref_for_offset (location_t loc, tree base, poly_int64 offset,
1710                       bool reverse, tree exp_type, gimple_stmt_iterator *gsi,
1711                       bool insert_after)
1712 {
1713   tree prev_base = base;
1714   tree off;
1715   tree mem_ref;
1716   poly_int64 base_offset;
1717   unsigned HOST_WIDE_INT misalign;
1718   unsigned int align;
1719
1720   /* Preserve address-space information.  */
1721   addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (base));
1722   if (as != TYPE_ADDR_SPACE (exp_type))
1723     exp_type = build_qualified_type (exp_type,
1724                                      TYPE_QUALS (exp_type)
1725                                      | ENCODE_QUAL_ADDR_SPACE (as));
1726
1727   poly_int64 byte_offset = exact_div (offset, BITS_PER_UNIT);
1728   get_object_alignment_1 (base, &align, &misalign);
1729   base = get_addr_base_and_unit_offset (base, &base_offset);
1730
1731   /* get_addr_base_and_unit_offset returns NULL for references with a variable
1732      offset such as array[var_index].  */
1733   if (!base)
1734     {
1735       gassign *stmt;
1736       tree tmp, addr;
1737
1738       gcc_checking_assert (gsi);
1739       tmp = make_ssa_name (build_pointer_type (TREE_TYPE (prev_base)));
1740       addr = build_fold_addr_expr (unshare_expr (prev_base));
1741       STRIP_USELESS_TYPE_CONVERSION (addr);
1742       stmt = gimple_build_assign (tmp, addr);
1743       gimple_set_location (stmt, loc);
1744       if (insert_after)
1745         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
1746       else
1747         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
1748
1749       off = build_int_cst (reference_alias_ptr_type (prev_base), byte_offset);
1750       base = tmp;
1751     }
1752   else if (TREE_CODE (base) == MEM_REF)
1753     {
1754       off = build_int_cst (TREE_TYPE (TREE_OPERAND (base, 1)),
1755                            base_offset + byte_offset);
1756       off = int_const_binop (PLUS_EXPR, TREE_OPERAND (base, 1), off);
1757       base = unshare_expr (TREE_OPERAND (base, 0));
1758     }
1759   else
1760     {
1761       off = build_int_cst (reference_alias_ptr_type (prev_base),
1762                            base_offset + byte_offset);
1763       base = build_fold_addr_expr (unshare_expr (base));
1764     }
1765
1766   unsigned int align_bound = known_alignment (misalign + offset);
1767   if (align_bound != 0)
1768     align = MIN (align, align_bound);
1769   if (align != TYPE_ALIGN (exp_type))
1770     exp_type = build_aligned_type (exp_type, align);
1771
1772   mem_ref = fold_build2_loc (loc, MEM_REF, exp_type, base, off);
1773   REF_REVERSE_STORAGE_ORDER (mem_ref) = reverse;
1774   if (TREE_THIS_VOLATILE (prev_base))
1775     TREE_THIS_VOLATILE (mem_ref) = 1;
1776   if (TREE_SIDE_EFFECTS (prev_base))
1777     TREE_SIDE_EFFECTS (mem_ref) = 1;
1778   return mem_ref;
1779 }
1780
1781 /* Construct a memory reference to a part of an aggregate BASE at the given
1782    OFFSET and of the same type as MODEL.  In case this is a reference to a
1783    bit-field, the function will replicate the last component_ref of model's
1784    expr to access it.  GSI and INSERT_AFTER have the same meaning as in
1785    build_ref_for_offset.  */
1786
1787 static tree
1788 build_ref_for_model (location_t loc, tree base, HOST_WIDE_INT offset,
1789                      struct access *model, gimple_stmt_iterator *gsi,
1790                      bool insert_after)
1791 {
1792   if (TREE_CODE (model->expr) == COMPONENT_REF
1793       && DECL_BIT_FIELD (TREE_OPERAND (model->expr, 1)))
1794     {
1795       /* This access represents a bit-field.  */
1796       tree t, exp_type, fld = TREE_OPERAND (model->expr, 1);
1797
1798       offset -= int_bit_position (fld);
1799       exp_type = TREE_TYPE (TREE_OPERAND (model->expr, 0));
1800       t = build_ref_for_offset (loc, base, offset, model->reverse, exp_type,
1801                                 gsi, insert_after);
1802       /* The flag will be set on the record type.  */
1803       REF_REVERSE_STORAGE_ORDER (t) = 0;
1804       return fold_build3_loc (loc, COMPONENT_REF, TREE_TYPE (fld), t, fld,
1805                               NULL_TREE);
1806     }
1807   else
1808     return
1809       build_ref_for_offset (loc, base, offset, model->reverse, model->type,
1810                             gsi, insert_after);
1811 }
1812
1813 /* Attempt to build a memory reference that we could but into a gimple
1814    debug_bind statement.  Similar to build_ref_for_model but punts if it has to
1815    create statements and return s NULL instead.  This function also ignores
1816    alignment issues and so its results should never end up in non-debug
1817    statements.  */
1818
1819 static tree
1820 build_debug_ref_for_model (location_t loc, tree base, HOST_WIDE_INT offset,
1821                            struct access *model)
1822 {
1823   poly_int64 base_offset;
1824   tree off;
1825
1826   if (TREE_CODE (model->expr) == COMPONENT_REF
1827       && DECL_BIT_FIELD (TREE_OPERAND (model->expr, 1)))
1828     return NULL_TREE;
1829
1830   base = get_addr_base_and_unit_offset (base, &base_offset);
1831   if (!base)
1832     return NULL_TREE;
1833   if (TREE_CODE (base) == MEM_REF)
1834     {
1835       off = build_int_cst (TREE_TYPE (TREE_OPERAND (base, 1)),
1836                            base_offset + offset / BITS_PER_UNIT);
1837       off = int_const_binop (PLUS_EXPR, TREE_OPERAND (base, 1), off);
1838       base = unshare_expr (TREE_OPERAND (base, 0));
1839     }
1840   else
1841     {
1842       off = build_int_cst (reference_alias_ptr_type (base),
1843                            base_offset + offset / BITS_PER_UNIT);
1844       base = build_fold_addr_expr (unshare_expr (base));
1845     }
1846
1847   return fold_build2_loc (loc, MEM_REF, model->type, base, off);
1848 }
1849
1850 /* Construct a memory reference consisting of component_refs and array_refs to
1851    a part of an aggregate *RES (which is of type TYPE).  The requested part
1852    should have type EXP_TYPE at be the given OFFSET.  This function might not
1853    succeed, it returns true when it does and only then *RES points to something
1854    meaningful.  This function should be used only to build expressions that we
1855    might need to present to user (e.g. in warnings).  In all other situations,
1856    build_ref_for_model or build_ref_for_offset should be used instead.  */
1857
1858 static bool
1859 build_user_friendly_ref_for_offset (tree *res, tree type, HOST_WIDE_INT offset,
1860                                     tree exp_type)
1861 {
1862   while (1)
1863     {
1864       tree fld;
1865       tree tr_size, index, minidx;
1866       HOST_WIDE_INT el_size;
1867
1868       if (offset == 0 && exp_type
1869           && types_compatible_p (exp_type, type))
1870         return true;
1871
1872       switch (TREE_CODE (type))
1873         {
1874         case UNION_TYPE:
1875         case QUAL_UNION_TYPE:
1876         case RECORD_TYPE:
1877           for (fld = TYPE_FIELDS (type); fld; fld = DECL_CHAIN (fld))
1878             {
1879               HOST_WIDE_INT pos, size;
1880               tree tr_pos, expr, *expr_ptr;
1881
1882               if (TREE_CODE (fld) != FIELD_DECL)
1883                 continue;
1884
1885               tr_pos = bit_position (fld);
1886               if (!tr_pos || !tree_fits_uhwi_p (tr_pos))
1887                 continue;
1888               pos = tree_to_uhwi (tr_pos);
1889               gcc_assert (TREE_CODE (type) == RECORD_TYPE || pos == 0);
1890               tr_size = DECL_SIZE (fld);
1891               if (!tr_size || !tree_fits_uhwi_p (tr_size))
1892                 continue;
1893               size = tree_to_uhwi (tr_size);
1894               if (size == 0)
1895                 {
1896                   if (pos != offset)
1897                     continue;
1898                 }
1899               else if (pos > offset || (pos + size) <= offset)
1900                 continue;
1901
1902               expr = build3 (COMPONENT_REF, TREE_TYPE (fld), *res, fld,
1903                              NULL_TREE);
1904               expr_ptr = &expr;
1905               if (build_user_friendly_ref_for_offset (expr_ptr, TREE_TYPE (fld),
1906                                                       offset - pos, exp_type))
1907                 {
1908                   *res = expr;
1909                   return true;
1910                 }
1911             }
1912           return false;
1913
1914         case ARRAY_TYPE:
1915           tr_size = TYPE_SIZE (TREE_TYPE (type));
1916           if (!tr_size || !tree_fits_uhwi_p (tr_size))
1917             return false;
1918           el_size = tree_to_uhwi (tr_size);
1919
1920           minidx = TYPE_MIN_VALUE (TYPE_DOMAIN (type));
1921           if (TREE_CODE (minidx) != INTEGER_CST || el_size == 0)
1922             return false;
1923           index = build_int_cst (TYPE_DOMAIN (type), offset / el_size);
1924           if (!integer_zerop (minidx))
1925             index = int_const_binop (PLUS_EXPR, index, minidx);
1926           *res = build4 (ARRAY_REF, TREE_TYPE (type), *res, index,
1927                          NULL_TREE, NULL_TREE);
1928           offset = offset % el_size;
1929           type = TREE_TYPE (type);
1930           break;
1931
1932         default:
1933           if (offset != 0)
1934             return false;
1935
1936           if (exp_type)
1937             return false;
1938           else
1939             return true;
1940         }
1941     }
1942 }
1943
1944 /* Return true iff TYPE is stdarg va_list type.  */
1945
1946 static inline bool
1947 is_va_list_type (tree type)
1948 {
1949   return TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (va_list_type_node);
1950 }
1951
1952 /* Print message to dump file why a variable was rejected. */
1953
1954 static void
1955 reject (tree var, const char *msg)
1956 {
1957   if (dump_file && (dump_flags & TDF_DETAILS))
1958     {
1959       fprintf (dump_file, "Rejected (%d): %s: ", DECL_UID (var), msg);
1960       print_generic_expr (dump_file, var);
1961       fprintf (dump_file, "\n");
1962     }
1963 }
1964
1965 /* Return true if VAR is a candidate for SRA.  */
1966
1967 static bool
1968 maybe_add_sra_candidate (tree var)
1969 {
1970   tree type = TREE_TYPE (var);
1971   const char *msg;
1972   tree_node **slot;
1973
1974   if (!AGGREGATE_TYPE_P (type))
1975     {
1976       reject (var, "not aggregate");
1977       return false;
1978     }
1979   /* Allow constant-pool entries (that "need to live in memory")
1980      unless we are doing IPA SRA.  */
1981   if (needs_to_live_in_memory (var)
1982       && (sra_mode == SRA_MODE_EARLY_IPA || !constant_decl_p (var)))
1983     {
1984       reject (var, "needs to live in memory");
1985       return false;
1986     }
1987   if (TREE_THIS_VOLATILE (var))
1988     {
1989       reject (var, "is volatile");
1990       return false;
1991     }
1992   if (!COMPLETE_TYPE_P (type))
1993     {
1994       reject (var, "has incomplete type");
1995       return false;
1996     }
1997   if (!tree_fits_uhwi_p (TYPE_SIZE (type)))
1998     {
1999       reject (var, "type size not fixed");
2000       return false;
2001     }
2002   if (tree_to_uhwi (TYPE_SIZE (type)) == 0)
2003     {
2004       reject (var, "type size is zero");
2005       return false;
2006     }
2007   if (type_internals_preclude_sra_p (type, &msg))
2008     {
2009       reject (var, msg);
2010       return false;
2011     }
2012   if (/* Fix for PR 41089.  tree-stdarg.c needs to have va_lists intact but
2013          we also want to schedule it rather late.  Thus we ignore it in
2014          the early pass. */
2015       (sra_mode == SRA_MODE_EARLY_INTRA
2016        && is_va_list_type (type)))
2017     {
2018       reject (var, "is va_list");
2019       return false;
2020     }
2021
2022   bitmap_set_bit (candidate_bitmap, DECL_UID (var));
2023   slot = candidates->find_slot_with_hash (var, DECL_UID (var), INSERT);
2024   *slot = var;
2025
2026   if (dump_file && (dump_flags & TDF_DETAILS))
2027     {
2028       fprintf (dump_file, "Candidate (%d): ", DECL_UID (var));
2029       print_generic_expr (dump_file, var);
2030       fprintf (dump_file, "\n");
2031     }
2032
2033   return true;
2034 }
2035
2036 /* The very first phase of intraprocedural SRA.  It marks in candidate_bitmap
2037    those with type which is suitable for scalarization.  */
2038
2039 static bool
2040 find_var_candidates (void)
2041 {
2042   tree var, parm;
2043   unsigned int i;
2044   bool ret = false;
2045
2046   for (parm = DECL_ARGUMENTS (current_function_decl);
2047        parm;
2048        parm = DECL_CHAIN (parm))
2049     ret |= maybe_add_sra_candidate (parm);
2050
2051   FOR_EACH_LOCAL_DECL (cfun, i, var)
2052     {
2053       if (!VAR_P (var))
2054         continue;
2055
2056       ret |= maybe_add_sra_candidate (var);
2057     }
2058
2059   return ret;
2060 }
2061
2062 /* Sort all accesses for the given variable, check for partial overlaps and
2063    return NULL if there are any.  If there are none, pick a representative for
2064    each combination of offset and size and create a linked list out of them.
2065    Return the pointer to the first representative and make sure it is the first
2066    one in the vector of accesses.  */
2067
2068 static struct access *
2069 sort_and_splice_var_accesses (tree var)
2070 {
2071   int i, j, access_count;
2072   struct access *res, **prev_acc_ptr = &res;
2073   vec<access_p> *access_vec;
2074   bool first = true;
2075   HOST_WIDE_INT low = -1, high = 0;
2076
2077   access_vec = get_base_access_vector (var);
2078   if (!access_vec)
2079     return NULL;
2080   access_count = access_vec->length ();
2081
2082   /* Sort by <OFFSET, SIZE>.  */
2083   access_vec->qsort (compare_access_positions);
2084
2085   i = 0;
2086   while (i < access_count)
2087     {
2088       struct access *access = (*access_vec)[i];
2089       bool grp_write = access->write;
2090       bool grp_read = !access->write;
2091       bool grp_scalar_write = access->write
2092         && is_gimple_reg_type (access->type);
2093       bool grp_scalar_read = !access->write
2094         && is_gimple_reg_type (access->type);
2095       bool grp_assignment_read = access->grp_assignment_read;
2096       bool grp_assignment_write = access->grp_assignment_write;
2097       bool multiple_scalar_reads = false;
2098       bool total_scalarization = access->grp_total_scalarization;
2099       bool grp_partial_lhs = access->grp_partial_lhs;
2100       bool first_scalar = is_gimple_reg_type (access->type);
2101       bool unscalarizable_region = access->grp_unscalarizable_region;
2102       bool bf_non_full_precision
2103         = (INTEGRAL_TYPE_P (access->type)
2104            && TYPE_PRECISION (access->type) != access->size
2105            && TREE_CODE (access->expr) == COMPONENT_REF
2106            && DECL_BIT_FIELD (TREE_OPERAND (access->expr, 1)));
2107
2108       if (first || access->offset >= high)
2109         {
2110           first = false;
2111           low = access->offset;
2112           high = access->offset + access->size;
2113         }
2114       else if (access->offset > low && access->offset + access->size > high)
2115         return NULL;
2116       else
2117         gcc_assert (access->offset >= low
2118                     && access->offset + access->size <= high);
2119
2120       j = i + 1;
2121       while (j < access_count)
2122         {
2123           struct access *ac2 = (*access_vec)[j];
2124           if (ac2->offset != access->offset || ac2->size != access->size)
2125             break;
2126           if (ac2->write)
2127             {
2128               grp_write = true;
2129               grp_scalar_write = (grp_scalar_write
2130                                   || is_gimple_reg_type (ac2->type));
2131             }
2132           else
2133             {
2134               grp_read = true;
2135               if (is_gimple_reg_type (ac2->type))
2136                 {
2137                   if (grp_scalar_read)
2138                     multiple_scalar_reads = true;
2139                   else
2140                     grp_scalar_read = true;
2141                 }
2142             }
2143           grp_assignment_read |= ac2->grp_assignment_read;
2144           grp_assignment_write |= ac2->grp_assignment_write;
2145           grp_partial_lhs |= ac2->grp_partial_lhs;
2146           unscalarizable_region |= ac2->grp_unscalarizable_region;
2147           total_scalarization |= ac2->grp_total_scalarization;
2148           relink_to_new_repr (access, ac2);
2149
2150           /* If there are both aggregate-type and scalar-type accesses with
2151              this combination of size and offset, the comparison function
2152              should have put the scalars first.  */
2153           gcc_assert (first_scalar || !is_gimple_reg_type (ac2->type));
2154           /* It also prefers integral types to non-integral.  However, when the
2155              precision of the selected type does not span the entire area and
2156              should also be used for a non-integer (i.e. float), we must not
2157              let that happen.  Normally analyze_access_subtree expands the type
2158              to cover the entire area but for bit-fields it doesn't.  */
2159           if (bf_non_full_precision && !INTEGRAL_TYPE_P (ac2->type))
2160             {
2161               if (dump_file && (dump_flags & TDF_DETAILS))
2162                 {
2163                   fprintf (dump_file, "Cannot scalarize the following access "
2164                            "because insufficient precision integer type was "
2165                            "selected.\n  ");
2166                   dump_access (dump_file, access, false);
2167                 }
2168               unscalarizable_region = true;
2169             }
2170           ac2->group_representative = access;
2171           j++;
2172         }
2173
2174       i = j;
2175
2176       access->group_representative = access;
2177       access->grp_write = grp_write;
2178       access->grp_read = grp_read;
2179       access->grp_scalar_read = grp_scalar_read;
2180       access->grp_scalar_write = grp_scalar_write;
2181       access->grp_assignment_read = grp_assignment_read;
2182       access->grp_assignment_write = grp_assignment_write;
2183       access->grp_hint = total_scalarization
2184         || (multiple_scalar_reads && !constant_decl_p (var));
2185       access->grp_total_scalarization = total_scalarization;
2186       access->grp_partial_lhs = grp_partial_lhs;
2187       access->grp_unscalarizable_region = unscalarizable_region;
2188
2189       *prev_acc_ptr = access;
2190       prev_acc_ptr = &access->next_grp;
2191     }
2192
2193   gcc_assert (res == (*access_vec)[0]);
2194   return res;
2195 }
2196
2197 /* Create a variable for the given ACCESS which determines the type, name and a
2198    few other properties.  Return the variable declaration and store it also to
2199    ACCESS->replacement.  */
2200
2201 static tree
2202 create_access_replacement (struct access *access)
2203 {
2204   tree repl;
2205
2206   if (access->grp_to_be_debug_replaced)
2207     {
2208       repl = create_tmp_var_raw (access->type);
2209       DECL_CONTEXT (repl) = current_function_decl;
2210     }
2211   else
2212     /* Drop any special alignment on the type if it's not on the main
2213        variant.  This avoids issues with weirdo ABIs like AAPCS.  */
2214     repl = create_tmp_var (build_qualified_type
2215                              (TYPE_MAIN_VARIANT (access->type),
2216                               TYPE_QUALS (access->type)), "SR");
2217   if (TREE_CODE (access->type) == COMPLEX_TYPE
2218       || TREE_CODE (access->type) == VECTOR_TYPE)
2219     {
2220       if (!access->grp_partial_lhs)
2221         DECL_GIMPLE_REG_P (repl) = 1;
2222     }
2223   else if (access->grp_partial_lhs
2224            && is_gimple_reg_type (access->type))
2225     TREE_ADDRESSABLE (repl) = 1;
2226
2227   DECL_SOURCE_LOCATION (repl) = DECL_SOURCE_LOCATION (access->base);
2228   DECL_ARTIFICIAL (repl) = 1;
2229   DECL_IGNORED_P (repl) = DECL_IGNORED_P (access->base);
2230
2231   if (DECL_NAME (access->base)
2232       && !DECL_IGNORED_P (access->base)
2233       && !DECL_ARTIFICIAL (access->base))
2234     {
2235       char *pretty_name = make_fancy_name (access->expr);
2236       tree debug_expr = unshare_expr_without_location (access->expr), d;
2237       bool fail = false;
2238
2239       DECL_NAME (repl) = get_identifier (pretty_name);
2240       DECL_NAMELESS (repl) = 1;
2241       obstack_free (&name_obstack, pretty_name);
2242
2243       /* Get rid of any SSA_NAMEs embedded in debug_expr,
2244          as DECL_DEBUG_EXPR isn't considered when looking for still
2245          used SSA_NAMEs and thus they could be freed.  All debug info
2246          generation cares is whether something is constant or variable
2247          and that get_ref_base_and_extent works properly on the
2248          expression.  It cannot handle accesses at a non-constant offset
2249          though, so just give up in those cases.  */
2250       for (d = debug_expr;
2251            !fail && (handled_component_p (d) || TREE_CODE (d) == MEM_REF);
2252            d = TREE_OPERAND (d, 0))
2253         switch (TREE_CODE (d))
2254           {
2255           case ARRAY_REF:
2256           case ARRAY_RANGE_REF:
2257             if (TREE_OPERAND (d, 1)
2258                 && TREE_CODE (TREE_OPERAND (d, 1)) != INTEGER_CST)
2259               fail = true;
2260             if (TREE_OPERAND (d, 3)
2261                 && TREE_CODE (TREE_OPERAND (d, 3)) != INTEGER_CST)
2262               fail = true;
2263             /* FALLTHRU */
2264           case COMPONENT_REF:
2265             if (TREE_OPERAND (d, 2)
2266                 && TREE_CODE (TREE_OPERAND (d, 2)) != INTEGER_CST)
2267               fail = true;
2268             break;
2269           case MEM_REF:
2270             if (TREE_CODE (TREE_OPERAND (d, 0)) != ADDR_EXPR)
2271               fail = true;
2272             else
2273               d = TREE_OPERAND (d, 0);
2274             break;
2275           default:
2276             break;
2277           }
2278       if (!fail)
2279         {
2280           SET_DECL_DEBUG_EXPR (repl, debug_expr);
2281           DECL_HAS_DEBUG_EXPR_P (repl) = 1;
2282         }
2283       if (access->grp_no_warning)
2284         TREE_NO_WARNING (repl) = 1;
2285       else
2286         TREE_NO_WARNING (repl) = TREE_NO_WARNING (access->base);
2287     }
2288   else
2289     TREE_NO_WARNING (repl) = 1;
2290
2291   if (dump_file)
2292     {
2293       if (access->grp_to_be_debug_replaced)
2294         {
2295           fprintf (dump_file, "Created a debug-only replacement for ");
2296           print_generic_expr (dump_file, access->base);
2297           fprintf (dump_file, " offset: %u, size: %u\n",
2298                    (unsigned) access->offset, (unsigned) access->size);
2299         }
2300       else
2301         {
2302           fprintf (dump_file, "Created a replacement for ");
2303           print_generic_expr (dump_file, access->base);
2304           fprintf (dump_file, " offset: %u, size: %u: ",
2305                    (unsigned) access->offset, (unsigned) access->size);
2306           print_generic_expr (dump_file, repl);
2307           fprintf (dump_file, "\n");
2308         }
2309     }
2310   sra_stats.replacements++;
2311
2312   return repl;
2313 }
2314
2315 /* Return ACCESS scalar replacement, which must exist.  */
2316
2317 static inline tree
2318 get_access_replacement (struct access *access)
2319 {
2320   gcc_checking_assert (access->replacement_decl);
2321   return access->replacement_decl;
2322 }
2323
2324
2325 /* Build a subtree of accesses rooted in *ACCESS, and move the pointer in the
2326    linked list along the way.  Stop when *ACCESS is NULL or the access pointed
2327    to it is not "within" the root.  Return false iff some accesses partially
2328    overlap.  */
2329
2330 static bool
2331 build_access_subtree (struct access **access)
2332 {
2333   struct access *root = *access, *last_child = NULL;
2334   HOST_WIDE_INT limit = root->offset + root->size;
2335
2336   *access = (*access)->next_grp;
2337   while  (*access && (*access)->offset + (*access)->size <= limit)
2338     {
2339       if (!last_child)
2340         root->first_child = *access;
2341       else
2342         last_child->next_sibling = *access;
2343       last_child = *access;
2344       (*access)->parent = root;
2345       (*access)->grp_write |= root->grp_write;
2346
2347       if (!build_access_subtree (access))
2348         return false;
2349     }
2350
2351   if (*access && (*access)->offset < limit)
2352     return false;
2353
2354   return true;
2355 }
2356
2357 /* Build a tree of access representatives, ACCESS is the pointer to the first
2358    one, others are linked in a list by the next_grp field.  Return false iff
2359    some accesses partially overlap.  */
2360
2361 static bool
2362 build_access_trees (struct access *access)
2363 {
2364   while (access)
2365     {
2366       struct access *root = access;
2367
2368       if (!build_access_subtree (&access))
2369         return false;
2370       root->next_grp = access;
2371     }
2372   return true;
2373 }
2374
2375 /* Return true if expr contains some ARRAY_REFs into a variable bounded
2376    array.  */
2377
2378 static bool
2379 expr_with_var_bounded_array_refs_p (tree expr)
2380 {
2381   while (handled_component_p (expr))
2382     {
2383       if (TREE_CODE (expr) == ARRAY_REF
2384           && !tree_fits_shwi_p (array_ref_low_bound (expr)))
2385         return true;
2386       expr = TREE_OPERAND (expr, 0);
2387     }
2388   return false;
2389 }
2390
2391 /* Analyze the subtree of accesses rooted in ROOT, scheduling replacements when
2392    both seeming beneficial and when ALLOW_REPLACEMENTS allows it.  Also set all
2393    sorts of access flags appropriately along the way, notably always set
2394    grp_read and grp_assign_read according to MARK_READ and grp_write when
2395    MARK_WRITE is true.
2396
2397    Creating a replacement for a scalar access is considered beneficial if its
2398    grp_hint is set (this means we are either attempting total scalarization or
2399    there is more than one direct read access) or according to the following
2400    table:
2401
2402    Access written to through a scalar type (once or more times)
2403    |
2404    |    Written to in an assignment statement
2405    |    |
2406    |    |       Access read as scalar _once_
2407    |    |       |
2408    |    |       |       Read in an assignment statement
2409    |    |       |       |
2410    |    |       |       |       Scalarize       Comment
2411 -----------------------------------------------------------------------------
2412    0    0       0       0                       No access for the scalar
2413    0    0       0       1                       No access for the scalar
2414    0    0       1       0       No              Single read - won't help
2415    0    0       1       1       No              The same case
2416    0    1       0       0                       No access for the scalar
2417    0    1       0       1                       No access for the scalar
2418    0    1       1       0       Yes             s = *g; return s.i;
2419    0    1       1       1       Yes             The same case as above
2420    1    0       0       0       No              Won't help
2421    1    0       0       1       Yes             s.i = 1; *g = s;
2422    1    0       1       0       Yes             s.i = 5; g = s.i;
2423    1    0       1       1       Yes             The same case as above
2424    1    1       0       0       No              Won't help.
2425    1    1       0       1       Yes             s.i = 1; *g = s;
2426    1    1       1       0       Yes             s = *g; return s.i;
2427    1    1       1       1       Yes             Any of the above yeses  */
2428
2429 static bool
2430 analyze_access_subtree (struct access *root, struct access *parent,
2431                         bool allow_replacements)
2432 {
2433   struct access *child;
2434   HOST_WIDE_INT limit = root->offset + root->size;
2435   HOST_WIDE_INT covered_to = root->offset;
2436   bool scalar = is_gimple_reg_type (root->type);
2437   bool hole = false, sth_created = false;
2438
2439   if (parent)
2440     {
2441       if (parent->grp_read)
2442         root->grp_read = 1;
2443       if (parent->grp_assignment_read)
2444         root->grp_assignment_read = 1;
2445       if (parent->grp_write)
2446         root->grp_write = 1;
2447       if (parent->grp_assignment_write)
2448         root->grp_assignment_write = 1;
2449       if (parent->grp_total_scalarization)
2450         root->grp_total_scalarization = 1;
2451     }
2452
2453   if (root->grp_unscalarizable_region)
2454     allow_replacements = false;
2455
2456   if (allow_replacements && expr_with_var_bounded_array_refs_p (root->expr))
2457     allow_replacements = false;
2458
2459   for (child = root->first_child; child; child = child->next_sibling)
2460     {
2461       hole |= covered_to < child->offset;
2462       sth_created |= analyze_access_subtree (child, root,
2463                                              allow_replacements && !scalar);
2464
2465       root->grp_unscalarized_data |= child->grp_unscalarized_data;
2466       root->grp_total_scalarization &= child->grp_total_scalarization;
2467       if (child->grp_covered)
2468         covered_to += child->size;
2469       else
2470         hole = true;
2471     }
2472
2473   if (allow_replacements && scalar && !root->first_child
2474       && (root->grp_hint
2475           || ((root->grp_scalar_read || root->grp_assignment_read)
2476               && (root->grp_scalar_write || root->grp_assignment_write))))
2477     {
2478       /* Always create access replacements that cover the whole access.
2479          For integral types this means the precision has to match.
2480          Avoid assumptions based on the integral type kind, too.  */
2481       if (INTEGRAL_TYPE_P (root->type)
2482           && (TREE_CODE (root->type) != INTEGER_TYPE
2483               || TYPE_PRECISION (root->type) != root->size)
2484           /* But leave bitfield accesses alone.  */
2485           && (TREE_CODE (root->expr) != COMPONENT_REF
2486               || !DECL_BIT_FIELD (TREE_OPERAND (root->expr, 1))))
2487         {
2488           tree rt = root->type;
2489           gcc_assert ((root->offset % BITS_PER_UNIT) == 0
2490                       && (root->size % BITS_PER_UNIT) == 0);
2491           root->type = build_nonstandard_integer_type (root->size,
2492                                                        TYPE_UNSIGNED (rt));
2493           root->expr = build_ref_for_offset (UNKNOWN_LOCATION, root->base,
2494                                              root->offset, root->reverse,
2495                                              root->type, NULL, false);
2496
2497           if (dump_file && (dump_flags & TDF_DETAILS))
2498             {
2499               fprintf (dump_file, "Changing the type of a replacement for ");
2500               print_generic_expr (dump_file, root->base);
2501               fprintf (dump_file, " offset: %u, size: %u ",
2502                        (unsigned) root->offset, (unsigned) root->size);
2503               fprintf (dump_file, " to an integer.\n");
2504             }
2505         }
2506
2507       root->grp_to_be_replaced = 1;
2508       root->replacement_decl = create_access_replacement (root);
2509       sth_created = true;
2510       hole = false;
2511     }
2512   else
2513     {
2514       if (allow_replacements
2515           && scalar && !root->first_child
2516           && (root->grp_scalar_write || root->grp_assignment_write)
2517           && !bitmap_bit_p (cannot_scalarize_away_bitmap,
2518                             DECL_UID (root->base)))
2519         {
2520           gcc_checking_assert (!root->grp_scalar_read
2521                                && !root->grp_assignment_read);
2522           sth_created = true;
2523           if (MAY_HAVE_DEBUG_BIND_STMTS)
2524             {
2525               root->grp_to_be_debug_replaced = 1;
2526               root->replacement_decl = create_access_replacement (root);
2527             }
2528         }
2529
2530       if (covered_to < limit)
2531         hole = true;
2532       if (scalar || !allow_replacements)
2533         root->grp_total_scalarization = 0;
2534     }
2535
2536   if (!hole || root->grp_total_scalarization)
2537     root->grp_covered = 1;
2538   else if (root->grp_write || comes_initialized_p (root->base))
2539     root->grp_unscalarized_data = 1; /* not covered and written to */
2540   return sth_created;
2541 }
2542
2543 /* Analyze all access trees linked by next_grp by the means of
2544    analyze_access_subtree.  */
2545 static bool
2546 analyze_access_trees (struct access *access)
2547 {
2548   bool ret = false;
2549
2550   while (access)
2551     {
2552       if (analyze_access_subtree (access, NULL, true))
2553         ret = true;
2554       access = access->next_grp;
2555     }
2556
2557   return ret;
2558 }
2559
2560 /* Return true iff a potential new child of LACC at offset OFFSET and with size
2561    SIZE would conflict with an already existing one.  If exactly such a child
2562    already exists in LACC, store a pointer to it in EXACT_MATCH.  */
2563
2564 static bool
2565 child_would_conflict_in_lacc (struct access *lacc, HOST_WIDE_INT norm_offset,
2566                               HOST_WIDE_INT size, struct access **exact_match)
2567 {
2568   struct access *child;
2569
2570   for (child = lacc->first_child; child; child = child->next_sibling)
2571     {
2572       if (child->offset == norm_offset && child->size == size)
2573         {
2574           *exact_match = child;
2575           return true;
2576         }
2577
2578       if (child->offset < norm_offset + size
2579           && child->offset + child->size > norm_offset)
2580         return true;
2581     }
2582
2583   return false;
2584 }
2585
2586 /* Create a new child access of PARENT, with all properties just like MODEL
2587    except for its offset and with its grp_write false and grp_read true.
2588    Return the new access or NULL if it cannot be created.  Note that this
2589    access is created long after all splicing and sorting, it's not located in
2590    any access vector and is automatically a representative of its group.  Set
2591    the gpr_write flag of the new accesss if SET_GRP_WRITE is true.  */
2592
2593 static struct access *
2594 create_artificial_child_access (struct access *parent, struct access *model,
2595                                 HOST_WIDE_INT new_offset,
2596                                 bool set_grp_write)
2597 {
2598   struct access **child;
2599   tree expr = parent->base;
2600
2601   gcc_assert (!model->grp_unscalarizable_region);
2602
2603   struct access *access = access_pool.allocate ();
2604   memset (access, 0, sizeof (struct access));
2605   if (!build_user_friendly_ref_for_offset (&expr, TREE_TYPE (expr), new_offset,
2606                                            model->type))
2607     {
2608       access->grp_no_warning = true;
2609       expr = build_ref_for_model (EXPR_LOCATION (parent->base), parent->base,
2610                                   new_offset, model, NULL, false);
2611     }
2612
2613   access->base = parent->base;
2614   access->expr = expr;
2615   access->offset = new_offset;
2616   access->size = model->size;
2617   access->type = model->type;
2618   access->grp_write = set_grp_write;
2619   access->grp_read = false;
2620   access->reverse = model->reverse;
2621
2622   child = &parent->first_child;
2623   while (*child && (*child)->offset < new_offset)
2624     child = &(*child)->next_sibling;
2625
2626   access->next_sibling = *child;
2627   *child = access;
2628
2629   return access;
2630 }
2631
2632
2633 /* Beginning with ACCESS, traverse its whole access subtree and mark all
2634    sub-trees as written to.  If any of them has not been marked so previously
2635    and has assignment links leading from it, re-enqueue it.  */
2636
2637 static void
2638 subtree_mark_written_and_enqueue (struct access *access)
2639 {
2640   if (access->grp_write)
2641     return;
2642   access->grp_write = true;
2643   add_access_to_work_queue (access);
2644
2645   struct access *child;
2646   for (child = access->first_child; child; child = child->next_sibling)
2647     subtree_mark_written_and_enqueue (child);
2648 }
2649
2650 /* Propagate subaccesses and grp_write flags of RACC across an assignment link
2651    to LACC.  Enqueue sub-accesses as necessary so that the write flag is
2652    propagated transitively.  Return true if anything changed.  Additionally, if
2653    RACC is a scalar access but LACC is not, change the type of the latter, if
2654    possible.  */
2655
2656 static bool
2657 propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
2658 {
2659   struct access *rchild;
2660   HOST_WIDE_INT norm_delta = lacc->offset - racc->offset;
2661   bool ret = false;
2662
2663   /* IF the LHS is still not marked as being written to, we only need to do so
2664      if the RHS at this level actually was.  */
2665   if (!lacc->grp_write)
2666     {
2667       gcc_checking_assert (!comes_initialized_p (racc->base));
2668       if (racc->grp_write)
2669         {
2670           subtree_mark_written_and_enqueue (lacc);
2671           ret = true;
2672         }
2673     }
2674
2675   if (is_gimple_reg_type (lacc->type)
2676       || lacc->grp_unscalarizable_region
2677       || racc->grp_unscalarizable_region)
2678     {
2679       if (!lacc->grp_write)
2680         {
2681           ret = true;
2682           subtree_mark_written_and_enqueue (lacc);
2683         }
2684       return ret;
2685     }
2686
2687   if (is_gimple_reg_type (racc->type))
2688     {
2689       if (!lacc->grp_write)
2690         {
2691           ret = true;
2692           subtree_mark_written_and_enqueue (lacc);
2693         }
2694       if (!lacc->first_child && !racc->first_child)
2695         {
2696           tree t = lacc->base;
2697
2698           lacc->type = racc->type;
2699           if (build_user_friendly_ref_for_offset (&t, TREE_TYPE (t),
2700                                                   lacc->offset, racc->type))
2701             lacc->expr = t;
2702           else
2703             {
2704               lacc->expr = build_ref_for_model (EXPR_LOCATION (lacc->base),
2705                                                 lacc->base, lacc->offset,
2706                                                 racc, NULL, false);
2707               lacc->grp_no_warning = true;
2708             }
2709         }
2710       return ret;
2711     }
2712
2713   for (rchild = racc->first_child; rchild; rchild = rchild->next_sibling)
2714     {
2715       struct access *new_acc = NULL;
2716       HOST_WIDE_INT norm_offset = rchild->offset + norm_delta;
2717
2718       if (child_would_conflict_in_lacc (lacc, norm_offset, rchild->size,
2719                                         &new_acc))
2720         {
2721           if (new_acc)
2722             {
2723               if (!new_acc->grp_write && rchild->grp_write)
2724                 {
2725                   gcc_assert (!lacc->grp_write);
2726                   subtree_mark_written_and_enqueue (new_acc);
2727                   ret = true;
2728                 }
2729
2730               rchild->grp_hint = 1;
2731               new_acc->grp_hint |= new_acc->grp_read;
2732               if (rchild->first_child)
2733                 ret |= propagate_subaccesses_across_link (new_acc, rchild);
2734             }
2735           else
2736             {
2737               if (!lacc->grp_write)
2738                 {
2739                   ret = true;
2740                   subtree_mark_written_and_enqueue (lacc);
2741                 }
2742             }
2743           continue;
2744         }
2745
2746       if (rchild->grp_unscalarizable_region)
2747         {
2748           if (rchild->grp_write && !lacc->grp_write)
2749             {
2750               ret = true;
2751               subtree_mark_written_and_enqueue (lacc);
2752             }
2753           continue;
2754         }
2755
2756       rchild->grp_hint = 1;
2757       new_acc = create_artificial_child_access (lacc, rchild, norm_offset,
2758                                                 lacc->grp_write
2759                                                 || rchild->grp_write);
2760       gcc_checking_assert (new_acc);
2761       if (racc->first_child)
2762         propagate_subaccesses_across_link (new_acc, rchild);
2763
2764       add_access_to_work_queue (lacc);
2765       ret = true;
2766     }
2767
2768   return ret;
2769 }
2770
2771 /* Propagate all subaccesses across assignment links.  */
2772
2773 static void
2774 propagate_all_subaccesses (void)
2775 {
2776   while (work_queue_head)
2777     {
2778       struct access *racc = pop_access_from_work_queue ();
2779       struct assign_link *link;
2780
2781       if (racc->group_representative)
2782         racc= racc->group_representative;
2783       gcc_assert (racc->first_link);
2784
2785       for (link = racc->first_link; link; link = link->next)
2786         {
2787           struct access *lacc = link->lacc;
2788
2789           if (!bitmap_bit_p (candidate_bitmap, DECL_UID (lacc->base)))
2790             continue;
2791           lacc = lacc->group_representative;
2792
2793           bool reque_parents = false;
2794           if (!bitmap_bit_p (candidate_bitmap, DECL_UID (racc->base)))
2795             {
2796               if (!lacc->grp_write)
2797                 {
2798                   subtree_mark_written_and_enqueue (lacc);
2799                   reque_parents = true;
2800                 }
2801             }
2802           else if (propagate_subaccesses_across_link (lacc, racc))
2803             reque_parents = true;
2804
2805           if (reque_parents)
2806             do
2807               {
2808                 add_access_to_work_queue (lacc);
2809                 lacc = lacc->parent;
2810               }
2811             while (lacc);
2812         }
2813     }
2814 }
2815
2816 /* Go through all accesses collected throughout the (intraprocedural) analysis
2817    stage, exclude overlapping ones, identify representatives and build trees
2818    out of them, making decisions about scalarization on the way.  Return true
2819    iff there are any to-be-scalarized variables after this stage. */
2820
2821 static bool
2822 analyze_all_variable_accesses (void)
2823 {
2824   int res = 0;
2825   bitmap tmp = BITMAP_ALLOC (NULL);
2826   bitmap_iterator bi;
2827   unsigned i;
2828   bool optimize_speed_p = !optimize_function_for_size_p (cfun);
2829
2830   enum compiler_param param = optimize_speed_p
2831                         ? PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED
2832                         : PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE;
2833
2834   /* If the user didn't set PARAM_SRA_MAX_SCALARIZATION_SIZE_<...>,
2835      fall back to a target default.  */
2836   unsigned HOST_WIDE_INT max_scalarization_size
2837     = global_options_set.x_param_values[param]
2838       ? PARAM_VALUE (param)
2839       : get_move_ratio (optimize_speed_p) * UNITS_PER_WORD;
2840
2841   max_scalarization_size *= BITS_PER_UNIT;
2842
2843   EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
2844     if (bitmap_bit_p (should_scalarize_away_bitmap, i)
2845         && !bitmap_bit_p (cannot_scalarize_away_bitmap, i))
2846       {
2847         tree var = candidate (i);
2848
2849         if (VAR_P (var) && scalarizable_type_p (TREE_TYPE (var),
2850                                                 constant_decl_p (var)))
2851           {
2852             if (tree_to_uhwi (TYPE_SIZE (TREE_TYPE (var)))
2853                 <= max_scalarization_size)
2854               {
2855                 create_total_scalarization_access (var);
2856                 completely_scalarize (var, TREE_TYPE (var), 0, var);
2857                 statistics_counter_event (cfun,
2858                                           "Totally-scalarized aggregates", 1);
2859                 if (dump_file && (dump_flags & TDF_DETAILS))
2860                   {
2861                     fprintf (dump_file, "Will attempt to totally scalarize ");
2862                     print_generic_expr (dump_file, var);
2863                     fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2864                   }
2865               }
2866             else if (dump_file && (dump_flags & TDF_DETAILS))
2867               {
2868                 fprintf (dump_file, "Too big to totally scalarize: ");
2869                 print_generic_expr (dump_file, var);
2870                 fprintf (dump_file, " (UID: %u)\n", DECL_UID (var));
2871               }
2872           }
2873       }
2874
2875   bitmap_copy (tmp, candidate_bitmap);
2876   EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2877     {
2878       tree var = candidate (i);
2879       struct access *access;
2880
2881       access = sort_and_splice_var_accesses (var);
2882       if (!access || !build_access_trees (access))
2883         disqualify_candidate (var,
2884                               "No or inhibitingly overlapping accesses.");
2885     }
2886
2887   propagate_all_subaccesses ();
2888
2889   bitmap_copy (tmp, candidate_bitmap);
2890   EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, bi)
2891     {
2892       tree var = candidate (i);
2893       struct access *access = get_first_repr_for_decl (var);
2894
2895       if (analyze_access_trees (access))
2896         {
2897           res++;
2898           if (dump_file && (dump_flags & TDF_DETAILS))
2899             {
2900               fprintf (dump_file, "\nAccess trees for ");
2901               print_generic_expr (dump_file, var);
2902               fprintf (dump_file, " (UID: %u): \n", DECL_UID (var));
2903               dump_access_tree (dump_file, access);
2904               fprintf (dump_file, "\n");
2905             }
2906         }
2907       else
2908         disqualify_candidate (var, "No scalar replacements to be created.");
2909     }
2910
2911   BITMAP_FREE (tmp);
2912
2913   if (res)
2914     {
2915       statistics_counter_event (cfun, "Scalarized aggregates", res);
2916       return true;
2917     }
2918   else
2919     return false;
2920 }
2921
2922 /* Generate statements copying scalar replacements of accesses within a subtree
2923    into or out of AGG.  ACCESS, all its children, siblings and their children
2924    are to be processed.  AGG is an aggregate type expression (can be a
2925    declaration but does not have to be, it can for example also be a mem_ref or
2926    a series of handled components).  TOP_OFFSET is the offset of the processed
2927    subtree which has to be subtracted from offsets of individual accesses to
2928    get corresponding offsets for AGG.  If CHUNK_SIZE is non-null, copy only
2929    replacements in the interval <start_offset, start_offset + chunk_size>,
2930    otherwise copy all.  GSI is a statement iterator used to place the new
2931    statements.  WRITE should be true when the statements should write from AGG
2932    to the replacement and false if vice versa.  if INSERT_AFTER is true, new
2933    statements will be added after the current statement in GSI, they will be
2934    added before the statement otherwise.  */
2935
2936 static void
2937 generate_subtree_copies (struct access *access, tree agg,
2938                          HOST_WIDE_INT top_offset,
2939                          HOST_WIDE_INT start_offset, HOST_WIDE_INT chunk_size,
2940                          gimple_stmt_iterator *gsi, bool write,
2941                          bool insert_after, location_t loc)
2942 {
2943   /* Never write anything into constant pool decls.  See PR70602.  */
2944   if (!write && constant_decl_p (agg))
2945     return;
2946   do
2947     {
2948       if (chunk_size && access->offset >= start_offset + chunk_size)
2949         return;
2950
2951       if (access->grp_to_be_replaced
2952           && (chunk_size == 0
2953               || access->offset + access->size > start_offset))
2954         {
2955           tree expr, repl = get_access_replacement (access);
2956           gassign *stmt;
2957
2958           expr = build_ref_for_model (loc, agg, access->offset - top_offset,
2959                                       access, gsi, insert_after);
2960
2961           if (write)
2962             {
2963               if (access->grp_partial_lhs)
2964                 expr = force_gimple_operand_gsi (gsi, expr, true, NULL_TREE,
2965                                                  !insert_after,
2966                                                  insert_after ? GSI_NEW_STMT
2967                                                  : GSI_SAME_STMT);
2968               stmt = gimple_build_assign (repl, expr);
2969             }
2970           else
2971             {
2972               TREE_NO_WARNING (repl) = 1;
2973               if (access->grp_partial_lhs)
2974                 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
2975                                                  !insert_after,
2976                                                  insert_after ? GSI_NEW_STMT
2977                                                  : GSI_SAME_STMT);
2978               stmt = gimple_build_assign (expr, repl);
2979             }
2980           gimple_set_location (stmt, loc);
2981
2982           if (insert_after)
2983             gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
2984           else
2985             gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
2986           update_stmt (stmt);
2987           sra_stats.subtree_copies++;
2988         }
2989       else if (write
2990                && access->grp_to_be_debug_replaced
2991                && (chunk_size == 0
2992                    || access->offset + access->size > start_offset))
2993         {
2994           gdebug *ds;
2995           tree drhs = build_debug_ref_for_model (loc, agg,
2996                                                  access->offset - top_offset,
2997                                                  access);
2998           ds = gimple_build_debug_bind (get_access_replacement (access),
2999                                         drhs, gsi_stmt (*gsi));
3000           if (insert_after)
3001             gsi_insert_after (gsi, ds, GSI_NEW_STMT);
3002           else
3003             gsi_insert_before (gsi, ds, GSI_SAME_STMT);
3004         }
3005
3006       if (access->first_child)
3007         generate_subtree_copies (access->first_child, agg, top_offset,
3008                                  start_offset, chunk_size, gsi,
3009                                  write, insert_after, loc);
3010
3011       access = access->next_sibling;
3012     }
3013   while (access);
3014 }
3015
3016 /* Assign zero to all scalar replacements in an access subtree.  ACCESS is the
3017    root of the subtree to be processed.  GSI is the statement iterator used
3018    for inserting statements which are added after the current statement if
3019    INSERT_AFTER is true or before it otherwise.  */
3020
3021 static void
3022 init_subtree_with_zero (struct access *access, gimple_stmt_iterator *gsi,
3023                         bool insert_after, location_t loc)
3024
3025 {
3026   struct access *child;
3027
3028   if (access->grp_to_be_replaced)
3029     {
3030       gassign *stmt;
3031
3032       stmt = gimple_build_assign (get_access_replacement (access),
3033                                   build_zero_cst (access->type));
3034       if (insert_after)
3035         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
3036       else
3037         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
3038       update_stmt (stmt);
3039       gimple_set_location (stmt, loc);
3040     }
3041   else if (access->grp_to_be_debug_replaced)
3042     {
3043       gdebug *ds
3044         = gimple_build_debug_bind (get_access_replacement (access),
3045                                    build_zero_cst (access->type),
3046                                    gsi_stmt (*gsi));
3047       if (insert_after)
3048         gsi_insert_after (gsi, ds, GSI_NEW_STMT);
3049       else
3050         gsi_insert_before (gsi, ds, GSI_SAME_STMT);
3051     }
3052
3053   for (child = access->first_child; child; child = child->next_sibling)
3054     init_subtree_with_zero (child, gsi, insert_after, loc);
3055 }
3056
3057 /* Clobber all scalar replacements in an access subtree.  ACCESS is the
3058    root of the subtree to be processed.  GSI is the statement iterator used
3059    for inserting statements which are added after the current statement if
3060    INSERT_AFTER is true or before it otherwise.  */
3061
3062 static void
3063 clobber_subtree (struct access *access, gimple_stmt_iterator *gsi,
3064                 bool insert_after, location_t loc)
3065
3066 {
3067   struct access *child;
3068
3069   if (access->grp_to_be_replaced)
3070     {
3071       tree rep = get_access_replacement (access);
3072       tree clobber = build_constructor (access->type, NULL);
3073       TREE_THIS_VOLATILE (clobber) = 1;
3074       gimple *stmt = gimple_build_assign (rep, clobber);
3075
3076       if (insert_after)
3077         gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
3078       else
3079         gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
3080       update_stmt (stmt);
3081       gimple_set_location (stmt, loc);
3082     }
3083
3084   for (child = access->first_child; child; child = child->next_sibling)
3085     clobber_subtree (child, gsi, insert_after, loc);
3086 }
3087
3088 /* Search for an access representative for the given expression EXPR and
3089    return it or NULL if it cannot be found.  */
3090
3091 static struct access *
3092 get_access_for_expr (tree expr)
3093 {
3094   poly_int64 poffset, psize, pmax_size;
3095   HOST_WIDE_INT offset, max_size;
3096   tree base;
3097   bool reverse;
3098
3099   /* FIXME: This should not be necessary but Ada produces V_C_Es with a type of
3100      a different size than the size of its argument and we need the latter
3101      one.  */
3102   if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
3103     expr = TREE_OPERAND (expr, 0);
3104
3105   base = get_ref_base_and_extent (expr, &poffset, &psize, &pmax_size,
3106                                   &reverse);
3107   if (!known_size_p (pmax_size)
3108       || !pmax_size.is_constant (&max_size)
3109       || !poffset.is_constant (&offset)
3110       || !DECL_P (base))
3111     return NULL;
3112
3113   if (!bitmap_bit_p (candidate_bitmap, DECL_UID (base)))
3114     return NULL;
3115
3116   return get_var_base_offset_size_access (base, offset, max_size);
3117 }
3118
3119 /* Replace the expression EXPR with a scalar replacement if there is one and
3120    generate other statements to do type conversion or subtree copying if
3121    necessary.  GSI is used to place newly created statements, WRITE is true if
3122    the expression is being written to (it is on a LHS of a statement or output
3123    in an assembly statement).  */
3124
3125 static bool
3126 sra_modify_expr (tree *expr, gimple_stmt_iterator *gsi, bool write)
3127 {
3128   location_t loc;
3129   struct access *access;
3130   tree type, bfr, orig_expr;
3131
3132   if (TREE_CODE (*expr) == BIT_FIELD_REF)
3133     {
3134       bfr = *expr;
3135       expr = &TREE_OPERAND (*expr, 0);
3136     }
3137   else
3138     bfr = NULL_TREE;
3139
3140   if (TREE_CODE (*expr) == REALPART_EXPR || TREE_CODE (*expr) == IMAGPART_EXPR)
3141     expr = &TREE_OPERAND (*expr, 0);
3142   access = get_access_for_expr (*expr);
3143   if (!access)
3144     return false;
3145   type = TREE_TYPE (*expr);
3146   orig_expr = *expr;
3147
3148   loc = gimple_location (gsi_stmt (*gsi));
3149   gimple_stmt_iterator alt_gsi = gsi_none ();
3150   if (write && stmt_ends_bb_p (gsi_stmt (*gsi)))
3151     {
3152       alt_gsi = gsi_start_edge (single_non_eh_succ (gsi_bb (*gsi)));
3153       gsi = &alt_gsi;
3154     }
3155
3156   if (access->grp_to_be_replaced)
3157     {
3158       tree repl = get_access_replacement (access);
3159       /* If we replace a non-register typed access simply use the original
3160          access expression to extract the scalar component afterwards.
3161          This happens if scalarizing a function return value or parameter
3162          like in gcc.c-torture/execute/20041124-1.c, 20050316-1.c and
3163          gcc.c-torture/compile/20011217-1.c.
3164
3165          We also want to use this when accessing a complex or vector which can
3166          be accessed as a different type too, potentially creating a need for
3167          type conversion (see PR42196) and when scalarized unions are involved
3168          in assembler statements (see PR42398).  */
3169       if (!useless_type_conversion_p (type, access->type))
3170         {
3171           tree ref;
3172
3173           ref = build_ref_for_model (loc, orig_expr, 0, access, gsi, false);
3174
3175           if (write)
3176             {
3177               gassign *stmt;
3178
3179               if (access->grp_partial_lhs)
3180                 ref = force_gimple_operand_gsi (gsi, ref, true, NULL_TREE,
3181                                                  false, GSI_NEW_STMT);
3182               stmt = gimple_build_assign (repl, ref);
3183               gimple_set_location (stmt, loc);
3184               gsi_insert_after (gsi, stmt, GSI_NEW_STMT);
3185             }
3186           else
3187             {
3188               gassign *stmt;
3189
3190               if (access->grp_partial_lhs)
3191                 repl = force_gimple_operand_gsi (gsi, repl, true, NULL_TREE,
3192                                                  true, GSI_SAME_STMT);
3193               stmt = gimple_build_assign (ref, repl);
3194               gimple_set_location (stmt, loc);
3195               gsi_insert_before (gsi, stmt, GSI_SAME_STMT);
3196             }
3197         }
3198       else
3199         *expr = repl;
3200       sra_stats.exprs++;
3201     }
3202   else if (write && access->grp_to_be_debug_replaced)
3203     {
3204       gdebug *ds = gimple_build_debug_bind (get_access_replacement (access),
3205                                             NULL_TREE,
3206                                             gsi_stmt (*gsi));
3207       gsi_insert_after (gsi, ds, GSI_NEW_STMT);
3208     }
3209
3210   if (access->first_child)
3211     {
3212       HOST_WIDE_INT start_offset, chunk_size;
3213       if (bfr
3214           && tree_fits_uhwi_p (TREE_OPERAND (bfr, 1))
3215           && tree_fits_uhwi_p (TREE_OPERAND (bfr, 2)))
3216         {
3217           chunk_size = tree_to_uhwi (TREE_OPERAND (bfr, 1));
3218           start_offset = access->offset
3219             + tree_to_uhwi (TREE_OPERAND (bfr, 2));
3220         }
3221       else
3222         start_offset = chunk_size = 0;
3223
3224       generate_subtree_copies (access->first_child, orig_expr, access->offset,
3225                                start_offset, chunk_size, gsi, write, write,
3226                                loc);
3227     }
3228   return true;
3229 }
3230
3231 /* Where scalar replacements of the RHS have been written to when a replacement
3232    of a LHS of an assigments cannot be direclty loaded from a replacement of
3233    the RHS. */
3234 enum unscalarized_data_handling { SRA_UDH_NONE,  /* Nothing done so far. */
3235                                   SRA_UDH_RIGHT, /* Data flushed to the RHS. */
3236                                   SRA_UDH_LEFT }; /* Data flushed to the LHS. */
3237
3238 struct subreplacement_assignment_data
3239 {
3240   /* Offset of the access representing the lhs of the assignment.  */
3241   HOST_WIDE_INT left_offset;
3242
3243   /* LHS and RHS of the original assignment.  */
3244   tree assignment_lhs, assignment_rhs;
3245
3246   /* Access representing the rhs of the whole assignment.  */
3247   struct access *top_racc;
3248
3249   /* Stmt iterator used for statement insertions after the original assignment.
3250    It points to the main GSI used to traverse a BB during function body
3251    modification.  */
3252   gimple_stmt_iterator *new_gsi;
3253
3254   /* Stmt iterator used for statement insertions before the original
3255    assignment.  Keeps on pointing to the original statement.  */
3256   gimple_stmt_iterator old_gsi;
3257
3258   /* Location of the assignment.   */
3259   location_t loc;
3260
3261   /* Keeps the information whether we have needed to refresh replacements of
3262    the LHS and from which side of the assignments this takes place.  */
3263   enum unscalarized_data_handling refreshed;
3264 };
3265
3266 /* Store all replacements in the access tree rooted in TOP_RACC either to their
3267    base aggregate if there are unscalarized data or directly to LHS of the
3268    statement that is pointed to by GSI otherwise.  */
3269
3270 static void
3271 handle_unscalarized_data_in_subtree (struct subreplacement_assignment_data *sad)
3272 {
3273   tree src;
3274   if (sad->top_racc->grp_unscalarized_data)
3275     {
3276       src = sad->assignment_rhs;
3277       sad->refreshed = SRA_UDH_RIGHT;
3278     }
3279   else
3280     {
3281       src = sad->assignment_lhs;
3282       sad->refreshed = SRA_UDH_LEFT;
3283     }
3284   generate_subtree_copies (sad->top_racc->first_child, src,
3285                            sad->top_racc->offset, 0, 0,
3286                            &sad->old_gsi, false, false, sad->loc);
3287 }
3288
3289 /* Try to generate statements to load all sub-replacements in an access subtree
3290    formed by children of LACC from scalar replacements in the SAD->top_racc
3291    subtree.  If that is not possible, refresh the SAD->top_racc base aggregate
3292    and load the accesses from it.  */
3293
3294 static void
3295 load_assign_lhs_subreplacements (struct access *lacc,
3296                                  struct subreplacement_assignment_data *sad)
3297 {
3298   for (lacc = lacc->first_child; lacc; lacc = lacc->next_sibling)
3299     {
3300       HOST_WIDE_INT offset;
3301       offset = lacc->offset - sad->left_offset + sad->top_racc->offset;
3302
3303       if (lacc->grp_to_be_replaced)
3304         {
3305           struct access *racc;
3306           gassign *stmt;
3307           tree rhs;
3308
3309           racc = find_access_in_subtree (sad->top_racc, offset, lacc->size);
3310           if (racc && racc->grp_to_be_replaced)
3311             {
3312               rhs = get_access_replacement (racc);
3313               if (!useless_type_conversion_p (lacc->type, racc->type))
3314                 rhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
3315                                        lacc->type, rhs);
3316
3317               if (racc->grp_partial_lhs && lacc->grp_partial_lhs)
3318                 rhs = force_gimple_operand_gsi (&sad->old_gsi, rhs, true,
3319                                                 NULL_TREE, true, GSI_SAME_STMT);
3320             }
3321           else
3322             {
3323               /* No suitable access on the right hand side, need to load from
3324                  the aggregate.  See if we have to update it first... */
3325               if (sad->refreshed == SRA_UDH_NONE)
3326                 handle_unscalarized_data_in_subtree (sad);
3327
3328               if (sad->refreshed == SRA_UDH_LEFT)
3329                 rhs = build_ref_for_model (sad->loc, sad->assignment_lhs,
3330                                            lacc->offset - sad->left_offset,
3331                                            lacc, sad->new_gsi, true);
3332               else
3333                 rhs = build_ref_for_model (sad->loc, sad->assignment_rhs,
3334                                            lacc->offset - sad->left_offset,
3335                                            lacc, sad->new_gsi, true);
3336               if (lacc->grp_partial_lhs)
3337                 rhs = force_gimple_operand_gsi (sad->new_gsi,
3338                                                 rhs, true, NULL_TREE,
3339                                                 false, GSI_NEW_STMT);
3340             }
3341
3342           stmt = gimple_build_assign (get_access_replacement (lacc), rhs);
3343           gsi_insert_after (sad->new_gsi, stmt, GSI_NEW_STMT);
3344           gimple_set_location (stmt, sad->loc);
3345           update_stmt (stmt);
3346           sra_stats.subreplacements++;
3347         }
3348       else
3349         {
3350           if (sad->refreshed == SRA_UDH_NONE
3351               && lacc->grp_read && !lacc->grp_covered)
3352             handle_unscalarized_data_in_subtree (sad);
3353
3354           if (lacc && lacc->grp_to_be_debug_replaced)
3355             {
3356               gdebug *ds;
3357               tree drhs;
3358               struct access *racc = find_access_in_subtree (sad->top_racc,
3359                                                             offset,
3360                                                             lacc->size);
3361
3362               if (racc && racc->grp_to_be_replaced)
3363                 {
3364                   if (racc->grp_write || constant_decl_p (racc->base))
3365                     drhs = get_access_replacement (racc);
3366                   else
3367                     drhs = NULL;
3368                 }
3369               else if (sad->refreshed == SRA_UDH_LEFT)
3370                 drhs = build_debug_ref_for_model (sad->loc, lacc->base,
3371                                                   lacc->offset, lacc);
3372               else if (sad->refreshed == SRA_UDH_RIGHT)
3373                 drhs = build_debug_ref_for_model (sad->loc, sad->top_racc->base,
3374                                                   offset, lacc);
3375               else
3376                 drhs = NULL_TREE;
3377               if (drhs
3378                   && !useless_type_conversion_p (lacc->type, TREE_TYPE (drhs)))
3379                 drhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
3380                                         lacc->type, drhs);
3381               ds = gimple_build_debug_bind (get_access_replacement (lacc),
3382                                             drhs, gsi_stmt (sad->old_gsi));
3383               gsi_insert_after (sad->new_gsi, ds, GSI_NEW_STMT);
3384             }
3385         }
3386
3387       if (lacc->first_child)
3388         load_assign_lhs_subreplacements (lacc, sad);
3389     }
3390 }
3391
3392 /* Result code for SRA assignment modification.  */
3393 enum assignment_mod_result { SRA_AM_NONE,       /* nothing done for the stmt */
3394                              SRA_AM_MODIFIED,  /* stmt changed but not
3395                                                   removed */
3396                              SRA_AM_REMOVED };  /* stmt eliminated */
3397
3398 /* Modify assignments with a CONSTRUCTOR on their RHS.  STMT contains a pointer
3399    to the assignment and GSI is the statement iterator pointing at it.  Returns
3400    the same values as sra_modify_assign.  */
3401
3402 static enum assignment_mod_result
3403 sra_modify_constructor_assign (gimple *stmt, gimple_stmt_iterator *gsi)
3404 {
3405   tree lhs = gimple_assign_lhs (stmt);
3406   struct access *acc = get_access_for_expr (lhs);
3407   if (!acc)
3408     return SRA_AM_NONE;
3409   location_t loc = gimple_location (stmt);
3410
3411   if (gimple_clobber_p (stmt))
3412     {
3413       /* Clobber the replacement variable.  */
3414       clobber_subtree (acc, gsi, !acc->grp_covered, loc);
3415       /* Remove clobbers of fully scalarized variables, they are dead.  */
3416       if (acc->grp_covered)
3417         {
3418           unlink_stmt_vdef (stmt);
3419           gsi_remove (gsi, true);
3420           release_defs (stmt);
3421           return SRA_AM_REMOVED;
3422         }
3423       else
3424         return SRA_AM_MODIFIED;
3425     }
3426
3427   if (CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt)) > 0)
3428     {
3429       /* I have never seen this code path trigger but if it can happen the
3430          following should handle it gracefully.  */
3431       if (access_has_children_p (acc))
3432         generate_subtree_copies (acc->first_child, lhs, acc->offset, 0, 0, gsi,
3433                                  true, true, loc);
3434       return SRA_AM_MODIFIED;
3435     }
3436
3437   if (acc->grp_covered)
3438     {
3439       init_subtree_with_zero (acc, gsi, false, loc);
3440       unlink_stmt_vdef (stmt);
3441       gsi_remove (gsi, true);
3442       release_defs (stmt);
3443       return SRA_AM_REMOVED;
3444     }
3445   else
3446     {
3447       init_subtree_with_zero (acc, gsi, true, loc);
3448       return SRA_AM_MODIFIED;
3449     }
3450 }
3451
3452 /* Create and return a new suitable default definition SSA_NAME for RACC which
3453    is an access describing an uninitialized part of an aggregate that is being
3454    loaded.  */
3455
3456 static tree
3457 get_repl_default_def_ssa_name (struct access *racc)
3458 {
3459   gcc_checking_assert (!racc->grp_to_be_replaced
3460                        && !racc->grp_to_be_debug_replaced);
3461   if (!racc->replacement_decl)
3462     racc->replacement_decl = create_access_replacement (racc);
3463   return get_or_create_ssa_default_def (cfun, racc->replacement_decl);
3464 }
3465
3466 /* Examine both sides of the assignment statement pointed to by STMT, replace
3467    them with a scalare replacement if there is one and generate copying of
3468    replacements if scalarized aggregates have been used in the assignment.  GSI
3469    is used to hold generated statements for type conversions and subtree
3470    copying.  */
3471
3472 static enum assignment_mod_result
3473 sra_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi)
3474 {
3475   struct access *lacc, *racc;
3476   tree lhs, rhs;
3477   bool modify_this_stmt = false;
3478   bool force_gimple_rhs = false;
3479   location_t loc;
3480   gimple_stmt_iterator orig_gsi = *gsi;
3481
3482   if (!gimple_assign_single_p (stmt))
3483     return SRA_AM_NONE;
3484   lhs = gimple_assign_lhs (stmt);
3485   rhs = gimple_assign_rhs1 (stmt);
3486
3487   if (TREE_CODE (rhs) == CONSTRUCTOR)
3488     return sra_modify_constructor_assign (stmt, gsi);
3489
3490   if (TREE_CODE (rhs) == REALPART_EXPR || TREE_CODE (lhs) == REALPART_EXPR
3491       || TREE_CODE (rhs) == IMAGPART_EXPR || TREE_CODE (lhs) == IMAGPART_EXPR
3492       || TREE_CODE (rhs) == BIT_FIELD_REF || TREE_CODE (lhs) == BIT_FIELD_REF)
3493     {
3494       modify_this_stmt = sra_modify_expr (gimple_assign_rhs1_ptr (stmt),
3495                                           gsi, false);
3496       modify_this_stmt |= sra_modify_expr (gimple_assign_lhs_ptr (stmt),
3497                                            gsi, true);
3498       return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
3499     }
3500
3501   lacc = get_access_for_expr (lhs);
3502   racc = get_access_for_expr (rhs);
3503   if (!lacc && !racc)
3504     return SRA_AM_NONE;
3505   /* Avoid modifying initializations of constant-pool replacements.  */
3506   if (racc && (racc->replacement_decl == lhs))
3507     return SRA_AM_NONE;
3508
3509   loc = gimple_location (stmt);
3510   if (lacc && lacc->grp_to_be_replaced)
3511     {
3512       lhs = get_access_replacement (lacc);
3513       gimple_assign_set_lhs (stmt, lhs);
3514       modify_this_stmt = true;
3515       if (lacc->grp_partial_lhs)
3516         force_gimple_rhs = true;
3517       sra_stats.exprs++;
3518     }
3519
3520   if (racc && racc->grp_to_be_replaced)
3521     {
3522       rhs = get_access_replacement (racc);
3523       modify_this_stmt = true;
3524       if (racc->grp_partial_lhs)
3525         force_gimple_rhs = true;
3526       sra_stats.exprs++;
3527     }
3528   else if (racc
3529            && !racc->grp_unscalarized_data
3530            && !racc->grp_unscalarizable_region
3531            && TREE_CODE (lhs) == SSA_NAME
3532            && !access_has_replacements_p (racc))
3533     {
3534       rhs = get_repl_default_def_ssa_name (racc);
3535       modify_this_stmt = true;
3536       sra_stats.exprs++;
3537     }
3538
3539   if (modify_this_stmt)
3540     {
3541       if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
3542         {
3543           /* If we can avoid creating a VIEW_CONVERT_EXPR do so.
3544              ???  This should move to fold_stmt which we simply should
3545              call after building a VIEW_CONVERT_EXPR here.  */
3546           if (AGGREGATE_TYPE_P (TREE_TYPE (lhs))
3547               && !contains_bitfld_component_ref_p (lhs))
3548             {
3549               lhs = build_ref_for_model (loc, lhs, 0, racc, gsi, false);
3550               gimple_assign_set_lhs (stmt, lhs);
3551             }
3552           else if (AGGREGATE_TYPE_P (TREE_TYPE (rhs))
3553                    && !contains_vce_or_bfcref_p (rhs))
3554             rhs = build_ref_for_model (loc, rhs, 0, lacc, gsi, false);
3555
3556           if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
3557             {
3558               rhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR, TREE_TYPE (lhs),
3559                                      rhs);
3560               if (is_gimple_reg_type (TREE_TYPE (lhs))
3561                   && TREE_CODE (lhs) != SSA_NAME)
3562                 force_gimple_rhs = true;
3563             }
3564         }
3565     }
3566
3567   if (lacc && lacc->grp_to_be_debug_replaced)
3568     {
3569       tree dlhs = get_access_replacement (lacc);
3570       tree drhs = unshare_expr (rhs);
3571       if (!useless_type_conversion_p (TREE_TYPE (dlhs), TREE_TYPE (drhs)))
3572         {
3573           if (AGGREGATE_TYPE_P (TREE_TYPE (drhs))
3574               && !contains_vce_or_bfcref_p (drhs))
3575             drhs = build_debug_ref_for_model (loc, drhs, 0, lacc);
3576           if (drhs
3577               && !useless_type_conversion_p (TREE_TYPE (dlhs),
3578                                              TREE_TYPE (drhs)))
3579             drhs = fold_build1_loc (loc, VIEW_CONVERT_EXPR,
3580                                     TREE_TYPE (dlhs), drhs);
3581         }
3582       gdebug *ds = gimple_build_debug_bind (dlhs, drhs, stmt);
3583       gsi_insert_before (gsi, ds, GSI_SAME_STMT);
3584     }
3585
3586   /* From this point on, the function deals with assignments in between
3587      aggregates when at least one has scalar reductions of some of its
3588      components.  There are three possible scenarios: Both the LHS and RHS have
3589      to-be-scalarized components, 2) only the RHS has or 3) only the LHS has.
3590
3591      In the first case, we would like to load the LHS components from RHS
3592      components whenever possible.  If that is not possible, we would like to
3593      read it directly from the RHS (after updating it by storing in it its own
3594      components).  If there are some necessary unscalarized data in the LHS,
3595      those will be loaded by the original assignment too.  If neither of these
3596      cases happen, the original statement can be removed.  Most of this is done
3597      by load_assign_lhs_subreplacements.
3598
3599      In the second case, we would like to store all RHS scalarized components
3600      directly into LHS and if they cover the aggregate completely, remove the
3601      statement too.  In the third case, we want the LHS components to be loaded
3602      directly from the RHS (DSE will remove the original statement if it
3603      becomes redundant).
3604
3605      This is a bit complex but manageable when types match and when unions do
3606      not cause confusion in a way that we cannot really load a component of LHS
3607      from the RHS or vice versa (the access representing this level can have
3608      subaccesses that are accessible only through a different union field at a
3609      higher level - different from the one used in the examined expression).
3610      Unions are fun.
3611
3612      Therefore, I specially handle a fourth case, happening when there is a
3613      specific type cast or it is impossible to locate a scalarized subaccess on
3614      the other side of the expression.  If that happens, I simply "refresh" the
3615      RHS by storing in it is scalarized components leave the original statement
3616      there to do the copying and then load the scalar replacements of the LHS.
3617      This is what the first branch does.  */
3618
3619   if (modify_this_stmt
3620       || gimple_has_volatile_ops (stmt)
3621       || contains_vce_or_bfcref_p (rhs)
3622       || contains_vce_or_bfcref_p (lhs)
3623       || stmt_ends_bb_p (stmt))
3624     {
3625       /* No need to copy into a constant-pool, it comes pre-initialized.  */
3626       if (access_has_children_p (racc) && !constant_decl_p (racc->base))
3627         generate_subtree_copies (racc->first_child, rhs, racc->offset, 0, 0,
3628                                  gsi, false, false, loc);
3629       if (access_has_children_p (lacc))
3630         {
3631           gimple_stmt_iterator alt_gsi = gsi_none ();
3632           if (stmt_ends_bb_p (stmt))
3633             {
3634               alt_gsi = gsi_start_edge (single_non_eh_succ (gsi_bb (*gsi)));
3635               gsi = &alt_gsi;
3636             }
3637           generate_subtree_copies (lacc->first_child, lhs, lacc->offset, 0, 0,
3638                                    gsi, true, true, loc);
3639         }
3640       sra_stats.separate_lhs_rhs_handling++;
3641
3642       /* This gimplification must be done after generate_subtree_copies,
3643          lest we insert the subtree copies in the middle of the gimplified
3644          sequence.  */
3645       if (force_gimple_rhs)
3646         rhs = force_gimple_operand_gsi (&orig_gsi, rhs, true, NULL_TREE,
3647                                         true, GSI_SAME_STMT);
3648       if (gimple_assign_rhs1 (stmt) != rhs)
3649         {
3650           modify_this_stmt = true;
3651           gimple_assign_set_rhs_from_tree (&orig_gsi, rhs);
3652           gcc_assert (stmt == gsi_stmt (orig_gsi));
3653         }
3654
3655       return modify_this_stmt ? SRA_AM_MODIFIED : SRA_AM_NONE;
3656     }
3657   else
3658     {
3659       if (access_has_children_p (lacc)
3660           && access_has_children_p (racc)
3661           /* When an access represents an unscalarizable region, it usually
3662              represents accesses with variable offset and thus must not be used
3663              to generate new memory accesses.  */
3664           && !lacc->grp_unscalarizable_region
3665           && !racc->grp_unscalarizable_region)
3666         {
3667           struct subreplacement_assignment_data sad;
3668
3669           sad.left_offset = lacc->offset;
3670           sad.assignment_lhs = lhs;
3671           sad.assignment_rhs = rhs;
3672           sad.top_racc = racc;
3673           sad.old_gsi = *gsi;
3674           sad.new_gsi = gsi;
3675           sad.loc = gimple_location (stmt);
3676           sad.refreshed = SRA_UDH_NONE;
3677
3678           if (lacc->grp_read && !lacc->grp_covered)
3679             handle_unscalarized_data_in_subtree (&sad);
3680
3681           load_assign_lhs_subreplacements (lacc, &sad);
3682           if (sad.refreshed != SRA_UDH_RIGHT)
3683             {
3684               gsi_next (gsi);
3685               unlink_stmt_vdef (stmt);
3686               gsi_remove (&sad.old_gsi, true);
3687               release_defs (stmt);
3688               sra_stats.deleted++;
3689               return SRA_AM_REMOVED;
3690             }
3691         }
3692       else
3693         {
3694           if (access_has_children_p (racc)
3695               && !racc->grp_unscalarized_data
3696               && TREE_CODE (lhs) != SSA_NAME)
3697             {
3698               if (dump_file)
3699                 {
3700                   fprintf (dump_file, "Removing load: ");
3701                   print_gimple_stmt (dump_file, stmt, 0);
3702                 }
3703               generate_subtree_copies (racc->first_child, lhs,
3704                                        racc->offset, 0, 0, gsi,
3705                                        false, false, loc);
3706               gcc_assert (stmt == gsi_stmt (*gsi));
3707               unlink_stmt_vdef (stmt);
3708               gsi_remove (gsi, true);
3709               release_defs (stmt);
3710               sra_stats.deleted++;
3711               return SRA_AM_REMOVED;
3712             }
3713           /* Restore the aggregate RHS from its components so the
3714              prevailing aggregate copy does the right thing.  */
3715           if (access_has_children_p (racc))
3716             generate_subtree_copies (racc->first_child, rhs, racc->offset, 0, 0,
3717                                      gsi, false, false, loc);
3718           /* Re-load the components of the aggregate copy destination.
3719              But use the RHS aggregate to load from to expose more
3720              optimization opportunities.  */
3721           if (access_has_children_p (lacc))
3722             generate_subtree_copies (lacc->first_child, rhs, lacc->offset,
3723                                      0, 0, gsi, true, true, loc);
3724         }
3725
3726       return SRA_AM_NONE;
3727     }
3728 }
3729
3730 /* Set any scalar replacements of values in the constant pool to the initial
3731    value of the constant.  (Constant-pool decls like *.LC0 have effectively
3732    been initialized before the program starts, we must do the same for their
3733    replacements.)  Thus, we output statements like 'SR.1 = *.LC0[0];' into
3734    the function's entry block.  */
3735
3736 static void
3737 initialize_constant_pool_replacements (void)
3738 {
3739   gimple_seq seq = NULL;
3740   gimple_stmt_iterator gsi = gsi_start (seq);
3741   bitmap_iterator bi;
3742   unsigned i;
3743
3744   EXECUTE_IF_SET_IN_BITMAP (candidate_bitmap, 0, i, bi)
3745     {
3746       tree var = candidate (i);
3747       if (!constant_decl_p (var))
3748         continue;
3749       vec<access_p> *access_vec = get_base_access_vector (var);
3750       if (!access_vec)
3751         continue;
3752       for (unsigned i = 0; i < access_vec->length (); i++)
3753         {
3754           struct access *access = (*access_vec)[i];
3755           if (!access->replacement_decl)
3756             continue;
3757           gassign *stmt
3758             = gimple_build_assign (get_access_replacement (access),
3759                                    unshare_expr (access->expr));
3760           if (dump_file && (dump_flags & TDF_DETAILS))
3761             {
3762               fprintf (dump_file, "Generating constant initializer: ");
3763               print_gimple_stmt (dump_file, stmt, 0);
3764               fprintf (dump_file, "\n");
3765             }
3766           gsi_insert_after (&gsi, stmt, GSI_NEW_STMT);
3767           update_stmt (stmt);
3768         }
3769     }
3770
3771   seq = gsi_seq (gsi);
3772   if (seq)
3773     gsi_insert_seq_on_edge_immediate (
3774       single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)), seq);
3775 }
3776
3777 /* Traverse the function body and all modifications as decided in
3778    analyze_all_variable_accesses.  Return true iff the CFG has been
3779    changed.  */
3780
3781 static bool
3782 sra_modify_function_body (void)
3783 {
3784   bool cfg_changed = false;
3785   basic_block bb;
3786
3787   initialize_constant_pool_replacements ();
3788
3789   FOR_EACH_BB_FN (bb, cfun)
3790     {
3791       gimple_stmt_iterator gsi = gsi_start_bb (bb);
3792       while (!gsi_end_p (gsi))
3793         {
3794           gimple *stmt = gsi_stmt (gsi);
3795           enum assignment_mod_result assign_result;
3796           bool modified = false, deleted = false;
3797           tree *t;
3798           unsigned i;
3799
3800           switch (gimple_code (stmt))
3801             {
3802             case GIMPLE_RETURN:
3803               t = gimple_return_retval_ptr (as_a <greturn *> (stmt));
3804               if (*t != NULL_TREE)
3805                 modified |= sra_modify_expr (t, &gsi, false);
3806               break;
3807
3808             case GIMPLE_ASSIGN:
3809               assign_result = sra_modify_assign (stmt, &gsi);
3810               modified |= assign_result == SRA_AM_MODIFIED;
3811               deleted = assign_result == SRA_AM_REMOVED;
3812               break;
3813
3814             case GIMPLE_CALL:
3815               /* Operands must be processed before the lhs.  */
3816               for (i = 0; i < gimple_call_num_args (stmt); i++)
3817                 {
3818                   t = gimple_call_arg_ptr (stmt, i);
3819                   modified |= sra_modify_expr (t, &gsi, false);
3820                 }
3821
3822               if (gimple_call_lhs (stmt))
3823                 {
3824                   t = gimple_call_lhs_ptr (stmt);
3825                   modified |= sra_modify_expr (t, &gsi, true);
3826                 }
3827               break;
3828
3829             case GIMPLE_ASM:
3830               {
3831                 gasm *asm_stmt = as_a <gasm *> (stmt);
3832                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
3833                   {
3834                     t = &TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
3835                     modified |= sra_modify_expr (t, &gsi, false);
3836                   }
3837                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
3838                   {
3839                     t = &TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
3840                     modified |= sra_modify_expr (t, &gsi, true);
3841                   }
3842               }
3843               break;
3844
3845             default:
3846               break;
3847             }
3848
3849           if (modified)
3850             {
3851               update_stmt (stmt);
3852               if (maybe_clean_eh_stmt (stmt)
3853                   && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
3854                 cfg_changed = true;
3855             }
3856           if (!deleted)
3857             gsi_next (&gsi);
3858         }
3859     }
3860
3861   gsi_commit_edge_inserts ();
3862   return cfg_changed;
3863 }
3864
3865 /* Generate statements initializing scalar replacements of parts of function
3866    parameters.  */
3867
3868 static void
3869 initialize_parameter_reductions (void)
3870 {
3871   gimple_stmt_iterator gsi;
3872   gimple_seq seq = NULL;
3873   tree parm;
3874
3875   gsi = gsi_start (seq);
3876   for (parm = DECL_ARGUMENTS (current_function_decl);
3877        parm;
3878        parm = DECL_CHAIN (parm))
3879     {
3880       vec<access_p> *access_vec;
3881       struct access *access;
3882
3883       if (!bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
3884         continue;
3885       access_vec = get_base_access_vector (parm);
3886       if (!access_vec)
3887         continue;
3888
3889       for (access = (*access_vec)[0];
3890            access;
3891            access = access->next_grp)
3892         generate_subtree_copies (access, parm, 0, 0, 0, &gsi, true, true,
3893                                  EXPR_LOCATION (parm));
3894     }
3895
3896   seq = gsi_seq (gsi);
3897   if (seq)
3898     gsi_insert_seq_on_edge_immediate (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)), seq);
3899 }
3900
3901 /* The "main" function of intraprocedural SRA passes.  Runs the analysis and if
3902    it reveals there are components of some aggregates to be scalarized, it runs
3903    the required transformations.  */
3904 static unsigned int
3905 perform_intra_sra (void)
3906 {
3907   int ret = 0;
3908   sra_initialize ();
3909
3910   if (!find_var_candidates ())
3911     goto out;
3912
3913   if (!scan_function ())
3914     goto out;
3915
3916   if (!analyze_all_variable_accesses ())
3917     goto out;
3918
3919   if (sra_modify_function_body ())
3920     ret = TODO_update_ssa | TODO_cleanup_cfg;
3921   else
3922     ret = TODO_update_ssa;
3923   initialize_parameter_reductions ();
3924
3925   statistics_counter_event (cfun, "Scalar replacements created",
3926                             sra_stats.replacements);
3927   statistics_counter_event (cfun, "Modified expressions", sra_stats.exprs);
3928   statistics_counter_event (cfun, "Subtree copy stmts",
3929                             sra_stats.subtree_copies);
3930   statistics_counter_event (cfun, "Subreplacement stmts",
3931                             sra_stats.subreplacements);
3932   statistics_counter_event (cfun, "Deleted stmts", sra_stats.deleted);
3933   statistics_counter_event (cfun, "Separate LHS and RHS handling",
3934                             sra_stats.separate_lhs_rhs_handling);
3935
3936  out:
3937   sra_deinitialize ();
3938   return ret;
3939 }
3940
3941 /* Perform early intraprocedural SRA.  */
3942 static unsigned int
3943 early_intra_sra (void)
3944 {
3945   sra_mode = SRA_MODE_EARLY_INTRA;
3946   return perform_intra_sra ();
3947 }
3948
3949 /* Perform "late" intraprocedural SRA.  */
3950 static unsigned int
3951 late_intra_sra (void)
3952 {
3953   sra_mode = SRA_MODE_INTRA;
3954   return perform_intra_sra ();
3955 }
3956
3957
3958 static bool
3959 gate_intra_sra (void)
3960 {
3961   return flag_tree_sra != 0 && dbg_cnt (tree_sra);
3962 }
3963
3964
3965 namespace {
3966
3967 const pass_data pass_data_sra_early =
3968 {
3969   GIMPLE_PASS, /* type */
3970   "esra", /* name */
3971   OPTGROUP_NONE, /* optinfo_flags */
3972   TV_TREE_SRA, /* tv_id */
3973   ( PROP_cfg | PROP_ssa ), /* properties_required */
3974   0, /* properties_provided */
3975   0, /* properties_destroyed */
3976   0, /* todo_flags_start */
3977   TODO_update_ssa, /* todo_flags_finish */
3978 };
3979
3980 class pass_sra_early : public gimple_opt_pass
3981 {
3982 public:
3983   pass_sra_early (gcc::context *ctxt)
3984     : gimple_opt_pass (pass_data_sra_early, ctxt)
3985   {}
3986
3987   /* opt_pass methods: */
3988   virtual bool gate (function *) { return gate_intra_sra (); }
3989   virtual unsigned int execute (function *) { return early_intra_sra (); }
3990
3991 }; // class pass_sra_early
3992
3993 } // anon namespace
3994
3995 gimple_opt_pass *
3996 make_pass_sra_early (gcc::context *ctxt)
3997 {
3998   return new pass_sra_early (ctxt);
3999 }
4000
4001 namespace {
4002
4003 const pass_data pass_data_sra =
4004 {
4005   GIMPLE_PASS, /* type */
4006   "sra", /* name */
4007   OPTGROUP_NONE, /* optinfo_flags */
4008   TV_TREE_SRA, /* tv_id */
4009   ( PROP_cfg | PROP_ssa ), /* properties_required */
4010   0, /* properties_provided */
4011   0, /* properties_destroyed */
4012   TODO_update_address_taken, /* todo_flags_start */
4013   TODO_update_ssa, /* todo_flags_finish */
4014 };
4015
4016 class pass_sra : public gimple_opt_pass
4017 {
4018 public:
4019   pass_sra (gcc::context *ctxt)
4020     : gimple_opt_pass (pass_data_sra, ctxt)
4021   {}
4022
4023   /* opt_pass methods: */
4024   virtual bool gate (function *) { return gate_intra_sra (); }
4025   virtual unsigned int execute (function *) { return late_intra_sra (); }
4026
4027 }; // class pass_sra
4028
4029 } // anon namespace
4030
4031 gimple_opt_pass *
4032 make_pass_sra (gcc::context *ctxt)
4033 {
4034   return new pass_sra (ctxt);
4035 }
4036
4037
4038 /* Return true iff PARM (which must be a parm_decl) is an unused scalar
4039    parameter.  */
4040
4041 static bool
4042 is_unused_scalar_param (tree parm)
4043 {
4044   tree name;
4045   return (is_gimple_reg (parm)
4046           && (!(name = ssa_default_def (cfun, parm))
4047               || has_zero_uses (name)));
4048 }
4049
4050 /* Scan immediate uses of a default definition SSA name of a parameter PARM and
4051    examine whether there are any direct or otherwise infeasible ones.  If so,
4052    return true, otherwise return false.  PARM must be a gimple register with a
4053    non-NULL default definition.  */
4054
4055 static bool
4056 ptr_parm_has_direct_uses (tree parm)
4057 {
4058   imm_use_iterator ui;
4059   gimple *stmt;
4060   tree name = ssa_default_def (cfun, parm);
4061   bool ret = false;
4062
4063   FOR_EACH_IMM_USE_STMT (stmt, ui, name)
4064     {
4065       int uses_ok = 0;
4066       use_operand_p use_p;
4067
4068       if (is_gimple_debug (stmt))
4069         continue;
4070
4071       /* Valid uses include dereferences on the lhs and the rhs.  */
4072       if (gimple_has_lhs (stmt))
4073         {
4074           tree lhs = gimple_get_lhs (stmt);
4075           while (handled_component_p (lhs))
4076             lhs = TREE_OPERAND (lhs, 0);
4077           if (TREE_CODE (lhs) == MEM_REF
4078               && TREE_OPERAND (lhs, 0) == name
4079               && integer_zerop (TREE_OPERAND (lhs, 1))
4080               && types_compatible_p (TREE_TYPE (lhs),
4081                                      TREE_TYPE (TREE_TYPE (name)))
4082               && !TREE_THIS_VOLATILE (lhs))
4083             uses_ok++;
4084         }
4085       if (gimple_assign_single_p (stmt))
4086         {
4087           tree rhs = gimple_assign_rhs1 (stmt);
4088           while (handled_component_p (rhs))
4089             rhs = TREE_OPERAND (rhs, 0);
4090           if (TREE_CODE (rhs) == MEM_REF
4091               && TREE_OPERAND (rhs, 0) == name
4092               && integer_zerop (TREE_OPERAND (rhs, 1))
4093               && types_compatible_p (TREE_TYPE (rhs),
4094                                      TREE_TYPE (TREE_TYPE (name)))
4095               && !TREE_THIS_VOLATILE (rhs))
4096             uses_ok++;
4097         }
4098       else if (is_gimple_call (stmt))
4099         {
4100           unsigned i;
4101           for (i = 0; i < gimple_call_num_args (stmt); ++i)
4102             {
4103               tree arg = gimple_call_arg (stmt, i);
4104               while (handled_component_p (arg))
4105                 arg = TREE_OPERAND (arg, 0);
4106               if (TREE_CODE (arg) == MEM_REF
4107                   && TREE_OPERAND (arg, 0) == name
4108                   && integer_zerop (TREE_OPERAND (arg, 1))
4109                   && types_compatible_p (TREE_TYPE (arg),
4110                                          TREE_TYPE (TREE_TYPE (name)))
4111                   && !TREE_THIS_VOLATILE (arg))
4112                 uses_ok++;
4113             }
4114         }
4115
4116       /* If the number of valid uses does not match the number of
4117          uses in this stmt there is an unhandled use.  */
4118       FOR_EACH_IMM_USE_ON_STMT (use_p, ui)
4119         --uses_ok;
4120
4121       if (uses_ok != 0)
4122         ret = true;
4123
4124       if (ret)
4125         BREAK_FROM_IMM_USE_STMT (ui);
4126     }
4127
4128   return ret;
4129 }
4130
4131 /* Identify candidates for reduction for IPA-SRA based on their type and mark
4132    them in candidate_bitmap.  Note that these do not necessarily include
4133    parameter which are unused and thus can be removed.  Return true iff any
4134    such candidate has been found.  */
4135
4136 static bool
4137 find_param_candidates (void)
4138 {
4139   tree parm;
4140   int count = 0;
4141   bool ret = false;
4142   const char *msg;
4143
4144   for (parm = DECL_ARGUMENTS (current_function_decl);
4145        parm;
4146        parm = DECL_CHAIN (parm))
4147     {
4148       tree type = TREE_TYPE (parm);
4149       tree_node **slot;
4150
4151       count++;
4152
4153       if (TREE_THIS_VOLATILE (parm)
4154           || TREE_ADDRESSABLE (parm)
4155           || (!is_gimple_reg_type (type) && is_va_list_type (type)))
4156         continue;
4157
4158       if (is_unused_scalar_param (parm))
4159         {
4160           ret = true;
4161           continue;
4162         }
4163
4164       if (POINTER_TYPE_P (type))
4165         {
4166           type = TREE_TYPE (type);
4167
4168           if (TREE_CODE (type) == FUNCTION_TYPE
4169               || TYPE_VOLATILE (type)
4170               || (TREE_CODE (type) == ARRAY_TYPE
4171                   && TYPE_NONALIASED_COMPONENT (type))
4172               || !is_gimple_reg (parm)
4173               || is_va_list_type (type)
4174               || ptr_parm_has_direct_uses (parm))
4175             continue;
4176         }
4177       else if (!AGGREGATE_TYPE_P (type))
4178         continue;
4179
4180       if (!COMPLETE_TYPE_P (type)
4181           || !tree_fits_uhwi_p (TYPE_SIZE (type))
4182           || tree_to_uhwi (TYPE_SIZE (type)) == 0
4183           || (AGGREGATE_TYPE_P (type)
4184               && type_internals_preclude_sra_p (type, &msg)))
4185         continue;
4186
4187       bitmap_set_bit (candidate_bitmap, DECL_UID (parm));
4188       slot = candidates->find_slot_with_hash (parm, DECL_UID (parm), INSERT);
4189       *slot = parm;
4190
4191       ret = true;
4192       if (dump_file && (dump_flags & TDF_DETAILS))
4193         {
4194           fprintf (dump_file, "Candidate (%d): ", DECL_UID (parm));
4195           print_generic_expr (dump_file, parm);
4196           fprintf (dump_file, "\n");
4197         }
4198     }
4199
4200   func_param_count = count;
4201   return ret;
4202 }
4203
4204 /* Callback of walk_aliased_vdefs, marks the access passed as DATA as
4205    maybe_modified. */
4206
4207 static bool
4208 mark_maybe_modified (ao_ref *ao ATTRIBUTE_UNUSED, tree vdef ATTRIBUTE_UNUSED,
4209                      void *data)
4210 {
4211   struct access *repr = (struct access *) data;
4212
4213   repr->grp_maybe_modified = 1;
4214   return true;
4215 }
4216
4217 /* Analyze what representatives (in linked lists accessible from
4218    REPRESENTATIVES) can be modified by side effects of statements in the
4219    current function.  */
4220
4221 static void
4222 analyze_modified_params (vec<access_p> representatives)
4223 {
4224   int i;
4225
4226   for (i = 0; i < func_param_count; i++)
4227     {
4228       struct access *repr;
4229
4230       for (repr = representatives[i];
4231            repr;
4232            repr = repr->next_grp)
4233         {
4234           struct access *access;
4235           bitmap visited;
4236           ao_ref ar;
4237
4238           if (no_accesses_p (repr))
4239             continue;
4240           if (!POINTER_TYPE_P (TREE_TYPE (repr->base))
4241               || repr->grp_maybe_modified)
4242             continue;
4243
4244           ao_ref_init (&ar, repr->expr);
4245           visited = BITMAP_ALLOC (NULL);
4246           for (access = repr; access; access = access->next_sibling)
4247             {
4248               /* All accesses are read ones, otherwise grp_maybe_modified would
4249                  be trivially set.  */
4250               walk_aliased_vdefs (&ar, gimple_vuse (access->stmt),
4251                                   mark_maybe_modified, repr, &visited);
4252               if (repr->grp_maybe_modified)
4253                 break;
4254             }
4255           BITMAP_FREE (visited);
4256         }
4257     }
4258 }
4259
4260 /* Propagate distances in bb_dereferences in the opposite direction than the
4261    control flow edges, in each step storing the maximum of the current value
4262    and the minimum of all successors.  These steps are repeated until the table
4263    stabilizes.  Note that BBs which might terminate the functions (according to
4264    final_bbs bitmap) never updated in this way.  */
4265
4266 static void
4267 propagate_dereference_distances (void)
4268 {
4269   basic_block bb;
4270
4271   auto_vec<basic_block> queue (last_basic_block_for_fn (cfun));
4272   queue.quick_push (ENTRY_BLOCK_PTR_FOR_FN (cfun));
4273   FOR_EACH_BB_FN (bb, cfun)
4274     {
4275       queue.quick_push (bb);
4276       bb->aux = bb;
4277     }
4278
4279   while (!queue.is_empty ())
4280     {
4281       edge_iterator ei;
4282       edge e;
4283       bool change = false;
4284       int i;
4285
4286       bb = queue.pop ();
4287       bb->aux = NULL;
4288
4289       if (bitmap_bit_p (final_bbs, bb->index))
4290         continue;
4291
4292       for (i = 0; i < func_param_count; i++)
4293         {
4294           int idx = bb->index * func_param_count + i;
4295           bool first = true;
4296           HOST_WIDE_INT inh = 0;
4297
4298           FOR_EACH_EDGE (e, ei, bb->succs)
4299           {
4300             int succ_idx = e->dest->index * func_param_count + i;
4301
4302             if (e->src == EXIT_BLOCK_PTR_FOR_FN (cfun))
4303               continue;
4304
4305             if (first)
4306               {
4307                 first = false;
4308                 inh = bb_dereferences [succ_idx];
4309               }
4310             else if (bb_dereferences [succ_idx] < inh)
4311               inh = bb_dereferences [succ_idx];
4312           }
4313
4314           if (!first && bb_dereferences[idx] < inh)
4315             {
4316               bb_dereferences[idx] = inh;
4317               change = true;
4318             }
4319         }
4320
4321       if (change && !bitmap_bit_p (final_bbs, bb->index))
4322         FOR_EACH_EDGE (e, ei, bb->preds)
4323           {
4324             if (e->src->aux)
4325               continue;
4326
4327             e->src->aux = e->src;
4328             queue.quick_push (e->src);
4329           }
4330     }
4331 }
4332
4333 /* Dump a dereferences TABLE with heading STR to file F.  */
4334
4335 static void
4336 dump_dereferences_table (FILE *f, const char *str, HOST_WIDE_INT *table)
4337 {
4338   basic_block bb;
4339
4340   fprintf (dump_file, "%s", str);
4341   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun),
4342                   EXIT_BLOCK_PTR_FOR_FN (cfun), next_bb)
4343     {
4344       fprintf (f, "%4i  %i   ", bb->index, bitmap_bit_p (final_bbs, bb->index));
4345       if (bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
4346         {
4347           int i;
4348           for (i = 0; i < func_param_count; i++)
4349             {
4350               int idx = bb->index * func_param_count + i;
4351               fprintf (f, " %4" HOST_WIDE_INT_PRINT "d", table[idx]);
4352             }
4353         }
4354       fprintf (f, "\n");
4355     }
4356   fprintf (dump_file, "\n");
4357 }
4358
4359 /* Determine what (parts of) parameters passed by reference that are not
4360    assigned to are not certainly dereferenced in this function and thus the
4361    dereferencing cannot be safely moved to the caller without potentially
4362    introducing a segfault.  Mark such REPRESENTATIVES as
4363    grp_not_necessarilly_dereferenced.
4364
4365    The dereferenced maximum "distance," i.e. the offset + size of the accessed
4366    part is calculated rather than simple booleans are calculated for each
4367    pointer parameter to handle cases when only a fraction of the whole
4368    aggregate is allocated (see testsuite/gcc.c-torture/execute/ipa-sra-2.c for
4369    an example).
4370
4371    The maximum dereference distances for each pointer parameter and BB are
4372    already stored in bb_dereference.  This routine simply propagates these
4373    values upwards by propagate_dereference_distances and then compares the
4374    distances of individual parameters in the ENTRY BB to the equivalent
4375    distances of each representative of a (fraction of a) parameter.  */
4376
4377 static void
4378 analyze_caller_dereference_legality (vec<access_p> representatives)
4379 {
4380   int i;
4381
4382   if (dump_file && (dump_flags & TDF_DETAILS))
4383     dump_dereferences_table (dump_file,
4384                              "Dereference table before propagation:\n",
4385                              bb_dereferences);
4386
4387   propagate_dereference_distances ();
4388
4389   if (dump_file && (dump_flags & TDF_DETAILS))
4390     dump_dereferences_table (dump_file,
4391                              "Dereference table after propagation:\n",
4392                              bb_dereferences);
4393
4394   for (i = 0; i < func_param_count; i++)
4395     {
4396       struct access *repr = representatives[i];
4397       int idx = ENTRY_BLOCK_PTR_FOR_FN (cfun)->index * func_param_count + i;
4398
4399       if (!repr || no_accesses_p (repr))
4400         continue;
4401
4402       do
4403         {
4404           if ((repr->offset + repr->size) > bb_dereferences[idx])
4405             repr->grp_not_necessarilly_dereferenced = 1;
4406           repr = repr->next_grp;
4407         }
4408       while (repr);
4409     }
4410 }
4411
4412 /* Return the representative access for the parameter declaration PARM if it is
4413    a scalar passed by reference which is not written to and the pointer value
4414    is not used directly.  Thus, if it is legal to dereference it in the caller
4415    and we can rule out modifications through aliases, such parameter should be
4416    turned into one passed by value.  Return NULL otherwise.  */
4417
4418 static struct access *
4419 unmodified_by_ref_scalar_representative (tree parm)
4420 {
4421   int i, access_count;
4422   struct access *repr;
4423   vec<access_p> *access_vec;
4424
4425   access_vec = get_base_access_vector (parm);
4426   gcc_assert (access_vec);
4427   repr = (*access_vec)[0];
4428   if (repr->write)
4429     return NULL;
4430   repr->group_representative = repr;
4431
4432   access_count = access_vec->length ();
4433   for (i = 1; i < access_count; i++)
4434     {
4435       struct access *access = (*access_vec)[i];
4436       if (access->write)
4437         return NULL;
4438       access->group_representative = repr;
4439       access->next_sibling = repr->next_sibling;
4440       repr->next_sibling = access;
4441     }
4442
4443   repr->grp_read = 1;
4444   repr->grp_scalar_ptr = 1;
4445   return repr;
4446 }
4447
4448 /* Return true iff this ACCESS precludes IPA-SRA of the parameter it is
4449    associated with.  REQ_ALIGN is the minimum required alignment.  */
4450
4451 static bool
4452 access_precludes_ipa_sra_p (struct access *access, unsigned int req_align)
4453 {
4454   unsigned int exp_align;
4455   /* Avoid issues such as the second simple testcase in PR 42025.  The problem
4456      is incompatible assign in a call statement (and possibly even in asm
4457      statements).  This can be relaxed by using a new temporary but only for
4458      non-TREE_ADDRESSABLE types and is probably not worth the complexity. (In
4459      intraprocedural SRA we deal with this by keeping the old aggregate around,
4460      something we cannot do in IPA-SRA.)  */
4461   if (access->write
4462       && (is_gimple_call (access->stmt)
4463           || gimple_code (access->stmt) == GIMPLE_ASM))
4464     return true;
4465
4466   exp_align = get_object_alignment (access->expr);
4467   if (exp_align < req_align)
4468     return true;
4469
4470   return false;
4471 }
4472
4473
4474 /* Sort collected accesses for parameter PARM, identify representatives for
4475    each accessed region and link them together.  Return NULL if there are
4476    different but overlapping accesses, return the special ptr value meaning
4477    there are no accesses for this parameter if that is the case and return the
4478    first representative otherwise.  Set *RO_GRP if there is a group of accesses
4479    with only read (i.e. no write) accesses.  */
4480
4481 static struct access *
4482 splice_param_accesses (tree parm, bool *ro_grp)
4483 {
4484   int i, j, access_count, group_count;
4485   int total_size = 0;
4486   struct access *access, *res, **prev_acc_ptr = &res;
4487   vec<access_p> *access_vec;
4488
4489   access_vec = get_base_access_vector (parm);
4490   if (!access_vec)
4491     return &no_accesses_representant;
4492   access_count = access_vec->length ();
4493
4494   access_vec->qsort (compare_access_positions);
4495
4496   i = 0;
4497   total_size = 0;
4498   group_count = 0;
4499   while (i < access_count)
4500     {
4501       bool modification;
4502       tree a1_alias_type;
4503       access = (*access_vec)[i];
4504       modification = access->write;
4505       if (access_precludes_ipa_sra_p (access, TYPE_ALIGN (access->type)))
4506         return NULL;
4507       a1_alias_type = reference_alias_ptr_type (access->expr);
4508
4509       /* Access is about to become group representative unless we find some
4510          nasty overlap which would preclude us from breaking this parameter
4511          apart. */
4512
4513       j = i + 1;
4514       while (j < access_count)
4515         {
4516           struct access *ac2 = (*access_vec)[j];
4517           if (ac2->offset != access->offset)
4518             {
4519               /* All or nothing law for parameters. */
4520               if (access->offset + access->size > ac2->offset)
4521                 return NULL;
4522               else
4523                 break;
4524             }
4525           else if (ac2->size != access->size)
4526             return NULL;
4527
4528           if (access_precludes_ipa_sra_p (ac2, TYPE_ALIGN (access->type))
4529               || (ac2->type != access->type
4530                   && (TREE_ADDRESSABLE (ac2->type)
4531                       || TREE_ADDRESSABLE (access->type)))
4532               || (reference_alias_ptr_type (ac2->expr) != a1_alias_type))
4533             return NULL;
4534
4535           modification |= ac2->write;
4536           ac2->group_representative = access;
4537           ac2->next_sibling = access->next_sibling;
4538           access->next_sibling = ac2;
4539           j++;
4540         }
4541
4542       group_count++;
4543       access->grp_maybe_modified = modification;
4544       if (!modification)
4545         *ro_grp = true;
4546       *prev_acc_ptr = access;
4547       prev_acc_ptr = &access->next_grp;
4548       total_size += access->size;
4549       i = j;
4550     }
4551
4552   gcc_assert (group_count > 0);
4553   return res;
4554 }
4555
4556 /* Decide whether parameters with representative accesses given by REPR should
4557    be reduced into components.  */
4558
4559 static int
4560 decide_one_param_reduction (struct access *repr)
4561 {
4562   HOST_WIDE_INT total_size, cur_parm_size;
4563   bool by_ref;
4564   tree parm;
4565
4566   parm = repr->base;
4567   cur_parm_size = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (parm)));
4568   gcc_assert (cur_parm_size > 0);
4569
4570   if (POINTER_TYPE_P (TREE_TYPE (parm)))
4571     by_ref = true;
4572   else
4573     by_ref = false;
4574
4575   if (dump_file)
4576     {
4577       struct access *acc;
4578       fprintf (dump_file, "Evaluating PARAM group sizes for ");
4579       print_generic_expr (dump_file, parm);
4580       fprintf (dump_file, " (UID: %u): \n", DECL_UID (parm));
4581       for (acc = repr; acc; acc = acc->next_grp)
4582         dump_access (dump_file, acc, true);
4583     }
4584
4585   total_size = 0;
4586   int new_param_count = 0;
4587
4588   for (; repr; repr = repr->next_grp)
4589     {
4590       gcc_assert (parm == repr->base);
4591
4592       /* Taking the address of a non-addressable field is verboten.  */
4593       if (by_ref && repr->non_addressable)
4594         return 0;
4595
4596       /* Do not decompose a non-BLKmode param in a way that would
4597          create BLKmode params.  Especially for by-reference passing
4598          (thus, pointer-type param) this is hardly worthwhile.  */
4599       if (DECL_MODE (parm) != BLKmode
4600           && TYPE_MODE (repr->type) == BLKmode)
4601         return 0;
4602
4603       if (!by_ref || (!repr->grp_maybe_modified
4604                       && !repr->grp_not_necessarilly_dereferenced))
4605         total_size += repr->size;
4606       else
4607         total_size += cur_parm_size;
4608
4609       new_param_count++;
4610     }
4611
4612   gcc_assert (new_param_count > 0);
4613
4614   if (!by_ref)
4615     {
4616       if (total_size >= cur_parm_size)
4617         return 0;
4618     }
4619   else
4620     {
4621       int parm_num_limit;
4622       if (optimize_function_for_size_p (cfun))
4623         parm_num_limit = 1;
4624       else
4625         parm_num_limit = PARAM_VALUE (PARAM_IPA_SRA_PTR_GROWTH_FACTOR);
4626
4627       if (new_param_count > parm_num_limit
4628           || total_size > (parm_num_limit * cur_parm_size))
4629         return 0;
4630     }
4631
4632   if (dump_file)
4633     fprintf (dump_file, "    ....will be split into %i components\n",
4634              new_param_count);
4635   return new_param_count;
4636 }
4637
4638 /* The order of the following enums is important, we need to do extra work for
4639    UNUSED_PARAMS, BY_VAL_ACCESSES and UNMODIF_BY_REF_ACCESSES.  */
4640 enum ipa_splicing_result { NO_GOOD_ACCESS, UNUSED_PARAMS, BY_VAL_ACCESSES,
4641                           MODIF_BY_REF_ACCESSES, UNMODIF_BY_REF_ACCESSES };
4642
4643 /* Identify representatives of all accesses to all candidate parameters for
4644    IPA-SRA.  Return result based on what representatives have been found. */
4645
4646 static enum ipa_splicing_result
4647 splice_all_param_accesses (vec<access_p> &representatives)
4648 {
4649   enum ipa_splicing_result result = NO_GOOD_ACCESS;
4650   tree parm;
4651   struct access *repr;
4652
4653   representatives.create (func_param_count);
4654
4655   for (parm = DECL_ARGUMENTS (current_function_decl);
4656        parm;
4657        parm = DECL_CHAIN (parm))
4658     {
4659       if (is_unused_scalar_param (parm))
4660         {
4661           representatives.quick_push (&no_accesses_representant);
4662           if (result == NO_GOOD_ACCESS)
4663             result = UNUSED_PARAMS;
4664         }
4665       else if (POINTER_TYPE_P (TREE_TYPE (parm))
4666                && is_gimple_reg_type (TREE_TYPE (TREE_TYPE (parm)))
4667                && bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
4668         {
4669           repr = unmodified_by_ref_scalar_representative (parm);
4670           representatives.quick_push (repr);
4671           if (repr)
4672             result = UNMODIF_BY_REF_ACCESSES;
4673         }
4674       else if (bitmap_bit_p (candidate_bitmap, DECL_UID (parm)))
4675         {
4676           bool ro_grp = false;
4677           repr = splice_param_accesses (parm, &ro_grp);
4678           representatives.quick_push (repr);
4679
4680           if (repr && !no_accesses_p (repr))
4681             {
4682               if (POINTER_TYPE_P (TREE_TYPE (parm)))
4683                 {
4684                   if (ro_grp)
4685                     result = UNMODIF_BY_REF_ACCESSES;
4686                   else if (result < MODIF_BY_REF_ACCESSES)
4687                     result = MODIF_BY_REF_ACCESSES;
4688                 }
4689               else if (result < BY_VAL_ACCESSES)
4690                 result = BY_VAL_ACCESSES;
4691             }
4692           else if (no_accesses_p (repr) && (result == NO_GOOD_ACCESS))
4693             result = UNUSED_PARAMS;
4694         }
4695       else
4696         representatives.quick_push (NULL);
4697     }
4698
4699   if (result == NO_GOOD_ACCESS)
4700     {
4701       representatives.release ();
4702       return NO_GOOD_ACCESS;
4703     }
4704
4705   return result;
4706 }
4707
4708 /* Return the index of BASE in PARMS.  Abort if it is not found.  */
4709
4710 static inline int
4711 get_param_index (tree base, vec<tree> parms)
4712 {
4713   int i, len;
4714
4715   len = parms.length ();
4716   for (i = 0; i < len; i++)
4717     if (parms[i] == base)
4718       return i;
4719   gcc_unreachable ();
4720 }
4721
4722 /* Convert the decisions made at the representative level into compact
4723    parameter adjustments.  REPRESENTATIVES are pointers to first
4724    representatives of each param accesses, ADJUSTMENTS_COUNT is the expected
4725    final number of adjustments.  */
4726
4727 static ipa_parm_adjustment_vec
4728 turn_representatives_into_adjustments (vec<access_p> representatives,
4729                                        int adjustments_count)
4730 {
4731   vec<tree> parms;
4732   ipa_parm_adjustment_vec adjustments;
4733   tree parm;
4734   int i;
4735
4736   gcc_assert (adjustments_count > 0);
4737   parms = ipa_get_vector_of_formal_parms (current_function_decl);
4738   adjustments.create (adjustments_count);
4739   parm = DECL_ARGUMENTS (current_function_decl);
4740   for (i = 0; i < func_param_count; i++, parm = DECL_CHAIN (parm))
4741     {
4742       struct access *repr = representatives[i];
4743
4744       if (!repr || no_accesses_p (repr))
4745         {
4746           struct ipa_parm_adjustment adj;
4747
4748           memset (&adj, 0, sizeof (adj));
4749           adj.base_index = get_param_index (parm, parms);
4750           adj.base = parm;
4751           if (!repr)
4752             adj.op = IPA_PARM_OP_COPY;
4753           else
4754             adj.op = IPA_PARM_OP_REMOVE;
4755           adj.arg_prefix = "ISRA";
4756           adjustments.quick_push (adj);
4757         }
4758       else
4759         {
4760           struct ipa_parm_adjustment adj;
4761           int index = get_param_index (parm, parms);
4762
4763           for (; repr; repr = repr->next_grp)
4764             {
4765               memset (&adj, 0, sizeof (adj));
4766               gcc_assert (repr->base == parm);
4767               adj.base_index = index;
4768               adj.base = repr->base;
4769               adj.type = repr->type;
4770               adj.alias_ptr_type = reference_alias_ptr_type (repr->expr);
4771               adj.offset = repr->offset;
4772               adj.reverse = repr->reverse;
4773               adj.by_ref = (POINTER_TYPE_P (TREE_TYPE (repr->base))
4774                             && (repr->grp_maybe_modified
4775                                 || repr->grp_not_necessarilly_dereferenced));
4776               adj.arg_prefix = "ISRA";
4777               adjustments.quick_push (adj);
4778             }
4779         }
4780     }
4781   parms.release ();
4782   return adjustments;
4783 }
4784
4785 /* Analyze the collected accesses and produce a plan what to do with the
4786    parameters in the form of adjustments, NULL meaning nothing.  */
4787
4788 static ipa_parm_adjustment_vec
4789 analyze_all_param_acesses (void)
4790 {
4791   enum ipa_splicing_result repr_state;
4792   bool proceed = false;
4793   int i, adjustments_count = 0;
4794   vec<access_p> representatives;
4795   ipa_parm_adjustment_vec adjustments;
4796
4797   repr_state = splice_all_param_accesses (representatives);
4798   if (repr_state == NO_GOOD_ACCESS)
4799     return ipa_parm_adjustment_vec ();
4800
4801   /* If there are any parameters passed by reference which are not modified
4802      directly, we need to check whether they can be modified indirectly.  */
4803   if (repr_state == UNMODIF_BY_REF_ACCESSES)
4804     {
4805       analyze_caller_dereference_legality (representatives);
4806       analyze_modified_params (representatives);
4807     }
4808
4809   for (i = 0; i < func_param_count; i++)
4810     {
4811       struct access *repr = representatives[i];
4812
4813       if (repr && !no_accesses_p (repr))
4814         {
4815           if (repr->grp_scalar_ptr)
4816             {
4817               adjustments_count++;
4818               if (repr->grp_not_necessarilly_dereferenced
4819                   || repr->grp_maybe_modified)
4820                 representatives[i] = NULL;
4821               else
4822                 {
4823                   proceed = true;
4824                   sra_stats.scalar_by_ref_to_by_val++;
4825                 }
4826             }
4827           else
4828             {
4829               int new_components = decide_one_param_reduction (repr);
4830
4831               if (new_components == 0)
4832                 {
4833                   representatives[i] = NULL;
4834                   adjustments_count++;
4835                 }
4836               else
4837                 {
4838                   adjustments_count += new_components;
4839                   sra_stats.aggregate_params_reduced++;
4840                   sra_stats.param_reductions_created += new_components;
4841                   proceed = true;
4842                 }
4843             }
4844         }
4845       else
4846         {
4847           if (no_accesses_p (repr))
4848             {
4849               proceed = true;
4850               sra_stats.deleted_unused_parameters++;
4851             }
4852           adjustments_count++;
4853         }
4854     }
4855
4856   if (!proceed && dump_file)
4857     fprintf (dump_file, "NOT proceeding to change params.\n");
4858
4859   if (proceed)
4860     adjustments = turn_representatives_into_adjustments (representatives,
4861                                                          adjustments_count);
4862   else
4863     adjustments = ipa_parm_adjustment_vec ();
4864
4865   representatives.release ();
4866   return adjustments;
4867 }
4868
4869 /* If a parameter replacement identified by ADJ does not yet exist in the form
4870    of declaration, create it and record it, otherwise return the previously
4871    created one.  */
4872
4873 static tree
4874 get_replaced_param_substitute (struct ipa_parm_adjustment *adj)
4875 {
4876   tree repl;
4877   if (!adj->new_ssa_base)
4878     {
4879       char *pretty_name = make_fancy_name (adj->base);
4880
4881       repl = create_tmp_reg (TREE_TYPE (adj->base), "ISR");
4882       DECL_NAME (repl) = get_identifier (pretty_name);
4883       DECL_NAMELESS (repl) = 1;
4884       obstack_free (&name_obstack, pretty_name);
4885
4886       adj->new_ssa_base = repl;
4887     }
4888   else
4889     repl = adj->new_ssa_base;
4890   return repl;
4891 }
4892
4893 /* Find the first adjustment for a particular parameter BASE in a vector of
4894    ADJUSTMENTS which is not a copy_param.  Return NULL if there is no such
4895    adjustment. */
4896
4897 static struct ipa_parm_adjustment *
4898 get_adjustment_for_base (ipa_parm_adjustment_vec adjustments, tree base)
4899 {
4900   int i, len;
4901
4902   len = adjustments.length ();
4903   for (i = 0; i < len; i++)
4904     {
4905       struct ipa_parm_adjustment *adj;
4906
4907       adj = &adjustments[i];
4908       if (adj->op != IPA_PARM_OP_COPY && adj->base == base)
4909         return adj;
4910     }
4911
4912   return NULL;
4913 }
4914
4915 /* If OLD_NAME, which is being defined by statement STMT, is an SSA_NAME of a
4916    parameter which is to be removed because its value is not used, create a new
4917    SSA_NAME relating to a replacement VAR_DECL, replace all uses of the
4918    original with it and return it.  If there is no need to re-map, return NULL.
4919    ADJUSTMENTS is a pointer to a vector of IPA-SRA adjustments.  */
4920
4921 static tree
4922 replace_removed_params_ssa_names (tree old_name, gimple *stmt,
4923                                   ipa_parm_adjustment_vec adjustments)
4924 {
4925   struct ipa_parm_adjustment *adj;
4926   tree decl, repl, new_name;
4927
4928   if (TREE_CODE (old_name) != SSA_NAME)
4929     return NULL;
4930
4931   decl = SSA_NAME_VAR (old_name);
4932   if (decl == NULL_TREE
4933       || TREE_CODE (decl) != PARM_DECL)
4934     return NULL;
4935
4936   adj = get_adjustment_for_base (adjustments, decl);
4937   if (!adj)
4938     return NULL;
4939
4940   repl = get_replaced_param_substitute (adj);
4941   new_name = make_ssa_name (repl, stmt);
4942   SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name)
4943     = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (old_name);
4944
4945   if (dump_file)
4946     {
4947       fprintf (dump_file, "replacing an SSA name of a removed param ");
4948       print_generic_expr (dump_file, old_name);
4949       fprintf (dump_file, " with ");
4950       print_generic_expr (dump_file, new_name);
4951       fprintf (dump_file, "\n");
4952     }
4953
4954   replace_uses_by (old_name, new_name);
4955   return new_name;
4956 }
4957
4958 /* If the statement STMT contains any expressions that need to replaced with a
4959    different one as noted by ADJUSTMENTS, do so.  Handle any potential type
4960    incompatibilities (GSI is used to accommodate conversion statements and must
4961    point to the statement).  Return true iff the statement was modified.  */
4962
4963 static bool
4964 sra_ipa_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi,
4965                        ipa_parm_adjustment_vec adjustments)
4966 {
4967   tree *lhs_p, *rhs_p;
4968   bool any;
4969
4970   if (!gimple_assign_single_p (stmt))
4971     return false;
4972
4973   rhs_p = gimple_assign_rhs1_ptr (stmt);
4974   lhs_p = gimple_assign_lhs_ptr (stmt);
4975
4976   any = ipa_modify_expr (rhs_p, false, adjustments);
4977   any |= ipa_modify_expr (lhs_p, false, adjustments);
4978   if (any)
4979     {
4980       tree new_rhs = NULL_TREE;
4981
4982       if (!useless_type_conversion_p (TREE_TYPE (*lhs_p), TREE_TYPE (*rhs_p)))
4983         {
4984           if (TREE_CODE (*rhs_p) == CONSTRUCTOR)
4985             {
4986               /* V_C_Es of constructors can cause trouble (PR 42714).  */
4987               if (is_gimple_reg_type (TREE_TYPE (*lhs_p)))
4988                 *rhs_p = build_zero_cst (TREE_TYPE (*lhs_p));
4989               else
4990                 *rhs_p = build_constructor (TREE_TYPE (*lhs_p),
4991                                             NULL);
4992             }
4993           else
4994             new_rhs = fold_build1_loc (gimple_location (stmt),
4995                                        VIEW_CONVERT_EXPR, TREE_TYPE (*lhs_p),
4996                                        *rhs_p);
4997         }
4998       else if (REFERENCE_CLASS_P (*rhs_p)
4999                && is_gimple_reg_type (TREE_TYPE (*lhs_p))
5000                && !is_gimple_reg (*lhs_p))
5001         /* This can happen when an assignment in between two single field
5002            structures is turned into an assignment in between two pointers to
5003            scalars (PR 42237).  */
5004         new_rhs = *rhs_p;
5005
5006       if (new_rhs)
5007         {
5008           tree tmp = force_gimple_operand_gsi (gsi, new_rhs, true, NULL_TREE,
5009                                                true, GSI_SAME_STMT);
5010
5011           gimple_assign_set_rhs_from_tree (gsi, tmp);
5012         }
5013
5014       return true;
5015     }
5016
5017   return false;
5018 }
5019
5020 /* Traverse the function body and all modifications as described in
5021    ADJUSTMENTS.  Return true iff the CFG has been changed.  */
5022
5023 bool
5024 ipa_sra_modify_function_body (ipa_parm_adjustment_vec adjustments)
5025 {
5026   bool cfg_changed = false;
5027   basic_block bb;
5028
5029   FOR_EACH_BB_FN (bb, cfun)
5030     {
5031       gimple_stmt_iterator gsi;
5032
5033       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
5034         {
5035           gphi *phi = as_a <gphi *> (gsi_stmt (gsi));
5036           tree new_lhs, old_lhs = gimple_phi_result (phi);
5037           new_lhs = replace_removed_params_ssa_names (old_lhs, phi, adjustments);
5038           if (new_lhs)
5039             {
5040               gimple_phi_set_result (phi, new_lhs);
5041               release_ssa_name (old_lhs);
5042             }
5043         }
5044
5045       gsi = gsi_start_bb (bb);
5046       while (!gsi_end_p (gsi))
5047         {
5048           gimple *stmt = gsi_stmt (gsi);
5049           bool modified = false;
5050           tree *t;
5051           unsigned i;
5052
5053           switch (gimple_code (stmt))
5054             {
5055             case GIMPLE_RETURN:
5056               t = gimple_return_retval_ptr (as_a <greturn *> (stmt));
5057               if (*t != NULL_TREE)
5058                 modified |= ipa_modify_expr (t, true, adjustments);
5059               break;
5060
5061             case GIMPLE_ASSIGN:
5062               modified |= sra_ipa_modify_assign (stmt, &gsi, adjustments);
5063               break;
5064
5065             case GIMPLE_CALL:
5066               /* Operands must be processed before the lhs.  */
5067               for (i = 0; i < gimple_call_num_args (stmt); i++)
5068                 {
5069                   t = gimple_call_arg_ptr (stmt, i);
5070                   modified |= ipa_modify_expr (t, true, adjustments);
5071                 }
5072
5073               if (gimple_call_lhs (stmt))
5074                 {
5075                   t = gimple_call_lhs_ptr (stmt);
5076                   modified |= ipa_modify_expr (t, false, adjustments);
5077                 }
5078               break;
5079
5080             case GIMPLE_ASM:
5081               {
5082                 gasm *asm_stmt = as_a <gasm *> (stmt);
5083                 for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
5084                   {
5085                     t = &TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
5086                     modified |= ipa_modify_expr (t, true, adjustments);
5087                   }
5088                 for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
5089                   {
5090                     t = &TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
5091                     modified |= ipa_modify_expr (t, false, adjustments);
5092                   }
5093               }
5094               break;
5095
5096             default:
5097               break;
5098             }
5099
5100           def_operand_p defp;
5101           ssa_op_iter iter;
5102           FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_DEF)
5103             {
5104               tree old_def = DEF_FROM_PTR (defp);
5105               if (tree new_def = replace_removed_params_ssa_names (old_def, stmt,
5106                                                                    adjustments))
5107                 {
5108                   SET_DEF (defp, new_def);
5109                   release_ssa_name (old_def);
5110                   modified = true;
5111                 }
5112             }
5113
5114           if (modified)
5115             {
5116               update_stmt (stmt);
5117               if (maybe_clean_eh_stmt (stmt)
5118                   && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
5119                 cfg_changed = true;
5120             }
5121           gsi_next (&gsi);
5122         }
5123     }
5124
5125   return cfg_changed;
5126 }
5127
5128 /* Call gimple_debug_bind_reset_value on all debug statements describing
5129    gimple register parameters that are being removed or replaced.  */
5130
5131 static void
5132 sra_ipa_reset_debug_stmts (ipa_parm_adjustment_vec adjustments)
5133 {
5134   int i, len;
5135   gimple_stmt_iterator *gsip = NULL, gsi;
5136
5137   if (MAY_HAVE_DEBUG_STMTS && single_succ_p (ENTRY_BLOCK_PTR_FOR_FN (cfun)))
5138     {
5139       gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
5140       gsip = &gsi;
5141     }
5142   len = adjustments.length ();
5143   for (i = 0; i < len; i++)
5144     {
5145       struct ipa_parm_adjustment *adj;
5146       imm_use_iterator ui;
5147       gimple *stmt;
5148       gdebug *def_temp;
5149       tree name, vexpr, copy = NULL_TREE;
5150       use_operand_p use_p;
5151
5152       adj = &adjustments[i];
5153       if (adj->op == IPA_PARM_OP_COPY || !is_gimple_reg (adj->base))
5154         continue;
5155       name = ssa_default_def (cfun, adj->base);
5156       vexpr = NULL;
5157       if (name)
5158         FOR_EACH_IMM_USE_STMT (stmt, ui, name)
5159           {
5160             if (gimple_clobber_p (stmt))
5161               {
5162                 gimple_stmt_iterator cgsi = gsi_for_stmt (stmt);
5163                 unlink_stmt_vdef (stmt);
5164                 gsi_remove (&cgsi, true);
5165                 release_defs (stmt);
5166                 continue;
5167               }
5168             /* All other users must have been removed by
5169                ipa_sra_modify_function_body.  */
5170             gcc_assert (is_gimple_debug (stmt));
5171             if (vexpr == NULL && gsip != NULL)
5172               {
5173                 gcc_assert (TREE_CODE (adj->base) == PARM_DECL);
5174                 vexpr = make_node (DEBUG_EXPR_DECL);
5175                 def_temp = gimple_build_debug_source_bind (vexpr, adj->base,
5176                                                            NULL);
5177                 DECL_ARTIFICIAL (vexpr) = 1;
5178                 TREE_TYPE (vexpr) = TREE_TYPE (name);
5179                 SET_DECL_MODE (vexpr, DECL_MODE (adj->base));
5180                 gsi_insert_before (gsip, def_temp, GSI_SAME_STMT);
5181               }
5182             if (vexpr)
5183               {
5184                 FOR_EACH_IMM_USE_ON_STMT (use_p, ui)
5185                   SET_USE (use_p, vexpr);
5186               }
5187             else
5188               gimple_debug_bind_reset_value (stmt);
5189             update_stmt (stmt);
5190           }
5191       /* Create a VAR_DECL for debug info purposes.  */
5192       if (!DECL_IGNORED_P (adj->base))
5193         {
5194           copy = build_decl (DECL_SOURCE_LOCATION (current_function_decl),
5195                              VAR_DECL, DECL_NAME (adj->base),
5196                              TREE_TYPE (adj->base));
5197           if (DECL_PT_UID_SET_P (adj->base))
5198             SET_DECL_PT_UID (copy, DECL_PT_UID (adj->base));
5199           TREE_ADDRESSABLE (copy) = TREE_ADDRESSABLE (adj->base);
5200           TREE_READONLY (copy) = TREE_READONLY (adj->base);
5201           TREE_THIS_VOLATILE (copy) = TREE_THIS_VOLATILE (adj->base);
5202           DECL_GIMPLE_REG_P (copy) = DECL_GIMPLE_REG_P (adj->base);
5203           DECL_ARTIFICIAL (copy) = DECL_ARTIFICIAL (adj->base);
5204           DECL_IGNORED_P (copy) = DECL_IGNORED_P (adj->base);
5205           DECL_ABSTRACT_ORIGIN (copy) = DECL_ORIGIN (adj->base);
5206           DECL_SEEN_IN_BIND_EXPR_P (copy) = 1;
5207           SET_DECL_RTL (copy, 0);
5208           TREE_USED (copy) = 1;
5209           DECL_CONTEXT (copy) = current_function_decl;
5210           add_local_decl (cfun, copy);
5211           DECL_CHAIN (copy) =
5212             BLOCK_VARS (DECL_INITIAL (current_function_decl));
5213           BLOCK_VARS (DECL_INITIAL (current_function_decl)) = copy;
5214         }
5215       if (gsip != NULL && copy && target_for_debug_bind (adj->base))
5216         {
5217           gcc_assert (TREE_CODE (adj->base) == PARM_DECL);
5218           if (vexpr)
5219             def_temp = gimple_build_debug_bind (copy, vexpr, NULL);
5220           else
5221             def_temp = gimple_build_debug_source_bind (copy, adj->base,
5222                                                        NULL);
5223           gsi_insert_before (gsip, def_temp, GSI_SAME_STMT);
5224         }
5225     }
5226 }
5227
5228 /* Return false if all callers have at least as many actual arguments as there
5229    are formal parameters in the current function and that their types
5230    match.  */
5231
5232 static bool
5233 some_callers_have_mismatched_arguments_p (struct cgraph_node *node,
5234                                           void *data ATTRIBUTE_UNUSED)
5235 {
5236   struct cgraph_edge *cs;
5237   for (cs = node->callers; cs; cs = cs->next_caller)
5238     if (!cs->call_stmt || !callsite_arguments_match_p (cs->call_stmt))
5239       return true;
5240
5241   return false;
5242 }
5243
5244 /* Return false if all callers have vuse attached to a call statement.  */
5245
5246 static bool
5247 some_callers_have_no_vuse_p (struct cgraph_node *node,
5248                              void *data ATTRIBUTE_UNUSED)
5249 {
5250   struct cgraph_edge *cs;
5251   for (cs = node->callers; cs; cs = cs->next_caller)
5252     if (!cs->call_stmt || !gimple_vuse (cs->call_stmt))
5253       return true;
5254
5255   return false;
5256 }
5257
5258 /* Convert all callers of NODE.  */
5259
5260 static bool
5261 convert_callers_for_node (struct cgraph_node *node,
5262                           void *data)
5263 {
5264   ipa_parm_adjustment_vec *adjustments = (ipa_parm_adjustment_vec *) data;
5265   bitmap recomputed_callers = BITMAP_ALLOC (NULL);
5266   struct cgraph_edge *cs;
5267
5268   for (cs = node->callers; cs; cs = cs->next_caller)
5269     {
5270       push_cfun (DECL_STRUCT_FUNCTION (cs->caller->decl));
5271
5272       if (dump_file)
5273         fprintf (dump_file, "Adjusting call %s -> %s\n",
5274                  cs->caller->dump_name (), cs->callee->dump_name ());
5275
5276       ipa_modify_call_arguments (cs, cs->call_stmt, *adjustments);
5277
5278       pop_cfun ();
5279     }
5280
5281   for (cs = node->callers; cs; cs = cs->next_caller)
5282     if (bitmap_set_bit (recomputed_callers, cs->caller->uid)
5283         && gimple_in_ssa_p (DECL_STRUCT_FUNCTION (cs->caller->decl)))
5284       compute_fn_summary (cs->caller, true);
5285   BITMAP_FREE (recomputed_callers);
5286
5287   return true;
5288 }
5289
5290 /* Convert all callers of NODE to pass parameters as given in ADJUSTMENTS.  */
5291
5292 static void
5293 convert_callers (struct cgraph_node *node, tree old_decl,
5294                  ipa_parm_adjustment_vec adjustments)
5295 {
5296   basic_block this_block;
5297
5298   node->call_for_symbol_and_aliases (convert_callers_for_node,
5299                                      &adjustments, false);
5300
5301   if (!encountered_recursive_call)
5302     return;
5303
5304   FOR_EACH_BB_FN (this_block, cfun)
5305     {
5306       gimple_stmt_iterator gsi;
5307
5308       for (gsi = gsi_start_bb (this_block); !gsi_end_p (gsi); gsi_next (&gsi))
5309         {
5310           gcall *stmt;
5311           tree call_fndecl;
5312           stmt = dyn_cast <gcall *> (gsi_stmt (gsi));
5313           if (!stmt)
5314             continue;
5315           call_fndecl = gimple_call_fndecl (stmt);
5316           if (call_fndecl == old_decl)
5317             {
5318               if (dump_file)
5319                 fprintf (dump_file, "Adjusting recursive call");
5320               gimple_call_set_fndecl (stmt, node->decl);
5321               ipa_modify_call_arguments (NULL, stmt, adjustments);
5322             }
5323         }
5324     }
5325
5326   return;
5327 }
5328
5329 /* Perform all the modification required in IPA-SRA for NODE to have parameters
5330    as given in ADJUSTMENTS.  Return true iff the CFG has been changed.  */
5331
5332 static bool
5333 modify_function (struct cgraph_node *node, ipa_parm_adjustment_vec adjustments)
5334 {
5335   struct cgraph_node *new_node;
5336   bool cfg_changed;
5337
5338   cgraph_edge::rebuild_edges ();
5339   free_dominance_info (CDI_DOMINATORS);
5340   pop_cfun ();
5341
5342   /* This must be done after rebuilding cgraph edges for node above.
5343      Otherwise any recursive calls to node that are recorded in
5344      redirect_callers will be corrupted.  */
5345   vec<cgraph_edge *> redirect_callers = node->collect_callers ();
5346   new_node = node->create_version_clone_with_body (redirect_callers, NULL,
5347                                                    NULL, false, NULL, NULL,
5348                                                    "isra");
5349   redirect_callers.release ();
5350
5351   push_cfun (DECL_STRUCT_FUNCTION (new_node->decl));
5352   ipa_modify_formal_parameters (current_function_decl, adjustments);
5353   cfg_changed = ipa_sra_modify_function_body (adjustments);
5354   sra_ipa_reset_debug_stmts (adjustments);
5355   convert_callers (new_node, node->decl, adjustments);
5356   new_node->make_local ();
5357   return cfg_changed;
5358 }
5359
5360 /* Means of communication between ipa_sra_check_caller and
5361    ipa_sra_preliminary_function_checks.  */
5362
5363 struct ipa_sra_check_caller_data
5364 {
5365   bool has_callers;
5366   bool bad_arg_alignment;
5367   bool has_thunk;
5368 };
5369
5370 /* If NODE has a caller, mark that fact in DATA which is pointer to
5371    ipa_sra_check_caller_data.  Also check all aggregate arguments in all known
5372    calls if they are unit aligned and if not, set the appropriate flag in DATA
5373    too. */
5374
5375 static bool
5376 ipa_sra_check_caller (struct cgraph_node *node, void *data)
5377 {
5378   if (!node->callers)
5379     return false;
5380
5381   struct ipa_sra_check_caller_data *iscc;
5382   iscc = (struct ipa_sra_check_caller_data *) data;
5383   iscc->has_callers = true;
5384
5385   for (cgraph_edge *cs = node->callers; cs; cs = cs->next_caller)
5386     {
5387       if (cs->caller->thunk.thunk_p)
5388         {
5389           iscc->has_thunk = true;
5390           return true;
5391         }
5392       gimple *call_stmt = cs->call_stmt;
5393       unsigned count = gimple_call_num_args (call_stmt);
5394       for (unsigned i = 0; i < count; i++)
5395         {
5396           tree arg = gimple_call_arg (call_stmt, i);
5397           if (is_gimple_reg (arg))
5398               continue;
5399
5400           tree offset;
5401           poly_int64 bitsize, bitpos;
5402           machine_mode mode;
5403           int unsignedp, reversep, volatilep = 0;
5404           get_inner_reference (arg, &bitsize, &bitpos, &offset, &mode,
5405                                &unsignedp, &reversep, &volatilep);
5406           if (!multiple_p (bitpos, BITS_PER_UNIT))
5407             {
5408               iscc->bad_arg_alignment = true;
5409               return true;
5410             }
5411         }
5412     }
5413
5414   return false;
5415 }
5416
5417 /* Return false the function is apparently unsuitable for IPA-SRA based on it's
5418    attributes, return true otherwise.  NODE is the cgraph node of the current
5419    function.  */
5420
5421 static bool
5422 ipa_sra_preliminary_function_checks (struct cgraph_node *node)
5423 {
5424   if (!node->can_be_local_p ())
5425     {
5426       if (dump_file)
5427         fprintf (dump_file, "Function not local to this compilation unit.\n");
5428       return false;
5429     }
5430
5431   if (!node->local.can_change_signature)
5432     {
5433       if (dump_file)
5434         fprintf (dump_file, "Function can not change signature.\n");
5435       return false;
5436     }
5437
5438   if (!tree_versionable_function_p (node->decl))
5439     {
5440       if (dump_file)
5441         fprintf (dump_file, "Function is not versionable.\n");
5442       return false;
5443     }
5444
5445   if (!opt_for_fn (node->decl, optimize)
5446       || !opt_for_fn (node->decl, flag_ipa_sra))
5447     {
5448       if (dump_file)
5449         fprintf (dump_file, "Function not optimized.\n");
5450       return false;
5451     }
5452
5453   if (DECL_VIRTUAL_P (current_function_decl))
5454     {
5455       if (dump_file)
5456         fprintf (dump_file, "Function is a virtual method.\n");
5457       return false;
5458     }
5459
5460   if ((DECL_ONE_ONLY (node->decl) || DECL_EXTERNAL (node->decl))
5461       && ipa_fn_summaries->get (node)->size >= MAX_INLINE_INSNS_AUTO)
5462     {
5463       if (dump_file)
5464         fprintf (dump_file, "Function too big to be made truly local.\n");
5465       return false;
5466     }
5467
5468   if (cfun->stdarg)
5469     {
5470       if (dump_file)
5471         fprintf (dump_file, "Function uses stdarg. \n");
5472       return false;
5473     }
5474
5475   if (TYPE_ATTRIBUTES (TREE_TYPE (node->decl)))
5476     return false;
5477
5478   if (DECL_DISREGARD_INLINE_LIMITS (node->decl))
5479     {
5480       if (dump_file)
5481         fprintf (dump_file, "Always inline function will be inlined "
5482                  "anyway. \n");
5483       return false;
5484     }
5485
5486   struct ipa_sra_check_caller_data iscc;
5487   memset (&iscc, 0, sizeof(iscc));
5488   node->call_for_symbol_and_aliases (ipa_sra_check_caller, &iscc, true);
5489   if (!iscc.has_callers)
5490     {
5491       if (dump_file)
5492         fprintf (dump_file,
5493                  "Function has no callers in this compilation unit.\n");
5494       return false;
5495     }
5496
5497   if (iscc.bad_arg_alignment)
5498     {
5499       if (dump_file)
5500         fprintf (dump_file,
5501                  "A function call has an argument with non-unit alignment.\n");
5502       return false;
5503     }
5504
5505   if (iscc.has_thunk)
5506     {
5507       if (dump_file)
5508         fprintf (dump_file,
5509                  "A has thunk.\n");
5510       return false;
5511     }
5512
5513   return true;
5514 }
5515
5516 /* Perform early interprocedural SRA.  */
5517
5518 static unsigned int
5519 ipa_early_sra (void)
5520 {
5521   struct cgraph_node *node = cgraph_node::get (current_function_decl);
5522   ipa_parm_adjustment_vec adjustments;
5523   int ret = 0;
5524
5525   if (!ipa_sra_preliminary_function_checks (node))
5526     return 0;
5527
5528   sra_initialize ();
5529   sra_mode = SRA_MODE_EARLY_IPA;
5530
5531   if (!find_param_candidates ())
5532     {
5533       if (dump_file)
5534         fprintf (dump_file, "Function has no IPA-SRA candidates.\n");
5535       goto simple_out;
5536     }
5537
5538   if (node->call_for_symbol_and_aliases
5539        (some_callers_have_mismatched_arguments_p, NULL, true))
5540     {
5541       if (dump_file)
5542         fprintf (dump_file, "There are callers with insufficient number of "
5543                  "arguments or arguments with type mismatches.\n");
5544       goto simple_out;
5545     }
5546
5547   if (node->call_for_symbol_and_aliases
5548        (some_callers_have_no_vuse_p, NULL, true))
5549     {
5550       if (dump_file)
5551         fprintf (dump_file, "There are callers with no VUSE attached "
5552                  "to a call stmt.\n");
5553       goto simple_out;
5554     }
5555
5556   bb_dereferences = XCNEWVEC (HOST_WIDE_INT,
5557                                  func_param_count
5558                                  * last_basic_block_for_fn (cfun));
5559   final_bbs = BITMAP_ALLOC (NULL);
5560
5561   scan_function ();
5562   if (encountered_apply_args)
5563     {
5564       if (dump_file)
5565         fprintf (dump_file, "Function calls  __builtin_apply_args().\n");
5566       goto out;
5567     }
5568
5569   if (encountered_unchangable_recursive_call)
5570     {
5571       if (dump_file)
5572         fprintf (dump_file, "Function calls itself with insufficient "
5573                  "number of arguments.\n");
5574       goto out;
5575     }
5576
5577   adjustments = analyze_all_param_acesses ();
5578   if (!adjustments.exists ())
5579     goto out;
5580   if (dump_file)
5581     ipa_dump_param_adjustments (dump_file, adjustments, current_function_decl);
5582
5583   if (modify_function (node, adjustments))
5584     ret = TODO_update_ssa | TODO_cleanup_cfg;
5585   else
5586     ret = TODO_update_ssa;
5587   adjustments.release ();
5588
5589   statistics_counter_event (cfun, "Unused parameters deleted",
5590                             sra_stats.deleted_unused_parameters);
5591   statistics_counter_event (cfun, "Scalar parameters converted to by-value",
5592                             sra_stats.scalar_by_ref_to_by_val);
5593   statistics_counter_event (cfun, "Aggregate parameters broken up",
5594                             sra_stats.aggregate_params_reduced);
5595   statistics_counter_event (cfun, "Aggregate parameter components created",
5596                             sra_stats.param_reductions_created);
5597
5598  out:
5599   BITMAP_FREE (final_bbs);
5600   free (bb_dereferences);
5601  simple_out:
5602   sra_deinitialize ();
5603   return ret;
5604 }
5605
5606 namespace {
5607
5608 const pass_data pass_data_early_ipa_sra =
5609 {
5610   GIMPLE_PASS, /* type */
5611   "eipa_sra", /* name */
5612   OPTGROUP_NONE, /* optinfo_flags */
5613   TV_IPA_SRA, /* tv_id */
5614   0, /* properties_required */
5615   0, /* properties_provided */
5616   0, /* properties_destroyed */
5617   0, /* todo_flags_start */
5618   TODO_dump_symtab, /* todo_flags_finish */
5619 };
5620
5621 class pass_early_ipa_sra : public gimple_opt_pass
5622 {
5623 public:
5624   pass_early_ipa_sra (gcc::context *ctxt)
5625     : gimple_opt_pass (pass_data_early_ipa_sra, ctxt)
5626   {}
5627
5628   /* opt_pass methods: */
5629   virtual bool gate (function *) { return flag_ipa_sra && dbg_cnt (eipa_sra); }
5630   virtual unsigned int execute (function *) { return ipa_early_sra (); }
5631
5632 }; // class pass_early_ipa_sra
5633
5634 } // anon namespace
5635
5636 gimple_opt_pass *
5637 make_pass_early_ipa_sra (gcc::context *ctxt)
5638 {
5639   return new pass_early_ipa_sra (ctxt);
5640 }