gcc/tree-ssa-operands.c

   1 /* SSA operands management for trees.
   2    Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GCC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "tree.h"
  26 #include "flags.h"
  27 #include "function.h"
  28 #include "diagnostic.h"
  29 #include "errors.h"
  30 #include "tree-flow.h"
  31 #include "tree-inline.h"
  32 #include "tree-pass.h"
  33 #include "ggc.h"
  34 #include "timevar.h"
  35
  36 #include "langhooks.h"
  37
  38 /* This file contains the code required to manage the operands cache of the
  39    SSA optimizer.  For every stmt, we maintain an operand cache in the stmt
  40    annotation.  This cache contains operands that will be of interest to
  41    optimizers and other passes wishing to manipulate the IL.
  42
  43    The operand type are broken up into REAL and VIRTUAL operands.  The real
  44    operands are represented as pointers into the stmt's operand tree.  Thus
  45    any manipulation of the real operands will be reflected in the actual tree.
  46    Virtual operands are represented solely in the cache, although the base
  47    variable for the SSA_NAME may, or may not occur in the stmt's tree.
  48    Manipulation of the virtual operands will not be reflected in the stmt tree.
  49
  50    The routines in this file are concerned with creating this operand cache
  51    from a stmt tree.
  52
  53    get_stmt_operands() in the primary entry point.
  54
  55    The operand tree is the parsed by the various get_* routines which look
  56    through the stmt tree for the occurrence of operands which may be of
  57    interest, and calls are made to the append_* routines whenever one is
  58    found.  There are 5 of these routines, each representing one of the
  59    5 types of operands. Defs, Uses, Virtual Uses, Virtual May Defs, and
  60    Virtual Must Defs.
  61
  62    The append_* routines check for duplication, and simply keep a list of
  63    unique objects for each operand type in the build_* extendable vectors.
  64
  65    Once the stmt tree is completely parsed, the finalize_ssa_operands()
  66    routine is called, which proceeds to perform the finalization routine
  67    on each of the 5 operand vectors which have been built up.
  68
  69    If the stmt had a previous operand cache, the finalization routines
  70    attempt to match up the new operands with the old ones.  If its a perfect
  71    match, the old vector is simply reused.  If it isn't a perfect match, then
  72    a new vector is created and the new operands are placed there.  For
  73    virtual operands, if the previous cache had SSA_NAME version of a
  74    variable, and that same variable occurs in the same operands cache, then
  75    the new cache vector will also get the same SSA_NAME.
  76
  77   i.e., if a stmt had a VUSE of 'a_5', and 'a' occurs in the new operand
  78   vector for VUSE, then the new vector will also be modified such that
  79   it contains 'a_5' rather than 'a'.
  80
  81 */
  82
  83
  84 /* Flags to describe operand properties in get_stmt_operands and helpers.  */
  85
  86 /* By default, operands are loaded.  */
  87 #define opf_none        0
  88
  89 /* Operand is the target of an assignment expression or a
  90    call-clobbered variable  */
  91 #define opf_is_def      (1 << 0)
  92
  93 /* Operand is the target of an assignment expression.  */
  94 #define opf_kill_def    (1 << 1)
  95
  96 /* No virtual operands should be created in the expression.  This is used
  97    when traversing ADDR_EXPR nodes which have different semantics than
  98    other expressions.  Inside an ADDR_EXPR node, the only operands that we
  99    need to consider are indices into arrays.  For instance, &a.b[i] should
 100    generate a USE of 'i' but it should not generate a VUSE for 'a' nor a
 101    VUSE for 'b'.  */
 102 #define opf_no_vops     (1 << 2)
 103
 104 /* Array for building all the def operands.  */
 105 static GTY (()) varray_type build_defs;
 106
 107 /* Array for building all the use operands.  */
 108 static GTY (()) varray_type build_uses;
 109
 110 /* Array for building all the v_may_def operands.  */
 111 static GTY (()) varray_type build_v_may_defs;
 112
 113 /* Array for building all the vuse operands.  */
 114 static GTY (()) varray_type build_vuses;
 115
 116 /* Array for building all the v_must_def operands.  */
 117 static GTY (()) varray_type build_v_must_defs;
 118
 119 /* True if the operands for call clobbered vars are cached and valid.  */
 120 bool ssa_call_clobbered_cache_valid;
 121 bool ssa_ro_call_cache_valid;
 122
 123 /* These arrays are the cached operand vectors for call clobbered calls.  */
 124 static GTY (()) varray_type clobbered_v_may_defs;
 125 static GTY (()) varray_type clobbered_vuses;
 126 static GTY (()) varray_type ro_call_vuses;
 127 static bool clobbered_aliased_loads;
 128 static bool clobbered_aliased_stores;
 129 static bool ro_call_aliased_loads;
 130 static stmt_operands_p parse_old_ops = NULL;
 131
 132 def_operand_p NULL_DEF_OPERAND_P = { NULL };
 133
 134 static void note_addressable (tree, stmt_ann_t);
 135 static void get_expr_operands (tree, tree *, int);
 136 static void get_asm_expr_operands (tree);
 137 static void get_indirect_ref_operands (tree, tree, int);
 138 static void get_call_expr_operands (tree, tree);
 139 static inline void append_def (tree *);
 140 static inline void append_use (tree *);
 141 static void append_v_may_def (tree);
 142 static void append_v_must_def (tree);
 143 static void add_call_clobber_ops (tree);
 144 static void add_call_read_ops (tree);
 145 static void add_stmt_operand (tree *, stmt_ann_t, int);
 146
 147 /* Return a vector of contiguous memory for NUM def operands.  */
 148
 149 static inline def_optype
 150 allocate_def_optype (unsigned num)
 151 {
 152   def_optype def_ops;
 153   unsigned size;
 154   size = sizeof (struct def_optype_d) + sizeof (tree *) * (num - 1);
 155   def_ops =  ggc_alloc (size);
 156   def_ops->num_defs = num;
 157   return def_ops;
 158 }
 159
 160
 161 /* Return a vector of contiguous memory for NUM use operands.  */
 162
 163 static inline use_optype
 164 allocate_use_optype (unsigned num)
 165 {
 166   use_optype use_ops;
 167   unsigned size;
 168   size = sizeof (struct use_optype_d) + sizeof (use_operand_type_t) * (num - 1);
 169   use_ops =  ggc_alloc (size);
 170   use_ops->num_uses = num;
 171   return use_ops;
 172 }
 173
 174
 175 /* Return a vector of contiguous memory for NUM v_may_def operands.  */
 176
 177 static inline v_may_def_optype
 178 allocate_v_may_def_optype (unsigned num)
 179 {
 180   v_may_def_optype v_may_def_ops;
 181   unsigned size;
 182   size = sizeof (struct v_may_def_optype_d)
 183            + sizeof (v_def_use_operand_type_t) * (num - 1);
 184   v_may_def_ops =  ggc_alloc (size);
 185   v_may_def_ops->num_v_may_defs = num;
 186   return v_may_def_ops;
 187 }
 188
 189
 190 /* Return a vector of contiguous memory for NUM v_use operands.  */
 191
 192 static inline vuse_optype
 193 allocate_vuse_optype (unsigned num)
 194 {
 195   vuse_optype vuse_ops;
 196   unsigned size;
 197   size = sizeof (struct vuse_optype_d)
 198        + sizeof (vuse_operand_type_t) * (num - 1);
 199   vuse_ops =  ggc_alloc (size);
 200   vuse_ops->num_vuses = num;
 201   return vuse_ops;
 202 }
 203
 204
 205 /* Return a vector of contiguous memory for NUM v_must_def operands.  */
 206
 207 static inline v_must_def_optype
 208 allocate_v_must_def_optype (unsigned num)
 209 {
 210   v_must_def_optype v_must_def_ops;
 211   unsigned size;
 212   size = sizeof (struct v_must_def_optype_d) + sizeof (v_def_use_operand_type_t) * (num - 1);
 213   v_must_def_ops =  ggc_alloc (size);
 214   v_must_def_ops->num_v_must_defs = num;
 215   return v_must_def_ops;
 216 }
 217
 218
 219 /* Free memory for USES.  */
 220
 221 static inline void
 222 free_uses (use_optype *uses)
 223 {
 224   if (*uses)
 225     {
 226       unsigned int x;
 227       use_optype use = *uses;
 228       for (x = 0; x < use->num_uses; x++)
 229         delink_imm_use (&(use->uses[x]));
 230       ggc_free (*uses);
 231       *uses = NULL;
 232     }
 233 }
 234
 235
 236 /* Free memory for DEFS.  */
 237
 238 static inline void
 239 free_defs (def_optype *defs)
 240 {
 241   if (*defs)
 242     {
 243       ggc_free (*defs);
 244       *defs = NULL;
 245     }
 246 }
 247
 248
 249 /* Free memory for VUSES.  */
 250
 251 static inline void
 252 free_vuses (vuse_optype *vuses)
 253 {
 254   if (*vuses)
 255     {
 256       unsigned int x;
 257       vuse_optype vuse = *vuses;
 258       for (x = 0; x < vuse->num_vuses; x++)
 259         delink_imm_use (&(vuse->vuses[x].imm_use));
 260       ggc_free (*vuses);
 261       *vuses = NULL;
 262     }
 263 }
 264
 265
 266 /* Free memory for V_MAY_DEFS.  */
 267
 268 static inline void
 269 free_v_may_defs (v_may_def_optype *v_may_defs)
 270 {
 271   if (*v_may_defs)
 272     {
 273       unsigned int x;
 274       v_may_def_optype v_may_def = *v_may_defs;
 275       for (x = 0; x < v_may_def->num_v_may_defs; x++)
 276         delink_imm_use (&(v_may_def->v_may_defs[x].imm_use));
 277       ggc_free (*v_may_defs);
 278       *v_may_defs = NULL;
 279     }
 280 }
 281
 282
 283 /* Free memory for V_MUST_DEFS.  */
 284
 285 static inline void
 286 free_v_must_defs (v_must_def_optype *v_must_defs)
 287 {
 288   if (*v_must_defs)
 289     {
 290       unsigned int x;
 291       v_must_def_optype v_must_def = *v_must_defs;
 292       for (x = 0; x < v_must_def->num_v_must_defs; x++)
 293         delink_imm_use (&(v_must_def->v_must_defs[x].imm_use));
 294       ggc_free (*v_must_defs);
 295       *v_must_defs = NULL;
 296     }
 297 }
 298
 299
 300 /* Initialize the operand cache routines.  */
 301
 302 void
 303 init_ssa_operands (void)
 304 {
 305   VARRAY_TREE_PTR_INIT (build_defs, 5, "build defs");
 306   VARRAY_TREE_PTR_INIT (build_uses, 10, "build uses");
 307   VARRAY_TREE_INIT (build_v_may_defs, 10, "build v_may_defs");
 308   VARRAY_TREE_INIT (build_vuses, 10, "build vuses");
 309   VARRAY_TREE_INIT (build_v_must_defs, 10, "build v_must_defs");
 310 }
 311
 312
 313 /* Dispose of anything required by the operand routines.  */
 314
 315 void
 316 fini_ssa_operands (void)
 317 {
 318   ggc_free (build_defs);
 319   ggc_free (build_uses);
 320   ggc_free (build_v_may_defs);
 321   ggc_free (build_vuses);
 322   ggc_free (build_v_must_defs);
 323   build_defs = NULL;
 324   build_uses = NULL;
 325   build_v_may_defs = NULL;
 326   build_vuses = NULL;
 327   build_v_must_defs = NULL;
 328   if (clobbered_v_may_defs)
 329     {
 330       ggc_free (clobbered_v_may_defs);
 331       ggc_free (clobbered_vuses);
 332       clobbered_v_may_defs = NULL;
 333       clobbered_vuses = NULL;
 334     }
 335   if (ro_call_vuses)
 336     {
 337       ggc_free (ro_call_vuses);
 338       ro_call_vuses = NULL;
 339     }
 340 }
 341
 342 /* Initialize V_USES index INDEX to VAL for STMT.  If OLD is present, preserve
 343    the position of the may-def in the immediate_use list.  */
 344
 345 static inline void
 346 initialize_vuse_operand (vuse_optype vuses, unsigned int index, tree val,
 347                          tree stmt, ssa_imm_use_t *old)
 348 {
 349   vuse_operand_type_t *ptr;
 350   ptr = &(vuses->vuses[index]);
 351   ptr->use = val;
 352   ptr->imm_use.use = &(ptr->use);
 353   if (old)
 354     relink_imm_use_stmt (&(ptr->imm_use), old, stmt);
 355   else
 356     link_imm_use_stmt (&(ptr->imm_use), ptr->use, stmt);
 357 }
 358
 359
 360 /* Initialize V_MAY_DEF_OPS index X to be DEF = MAY_DEF <USE> for STMT.  If
 361    OLD is present, preserve the position of the may-def in the immediate_use
 362    list.  */
 363
 364 static inline void
 365 initialize_v_may_def_operand (v_may_def_optype v_may_def_ops, unsigned int x,
 366                               tree def, tree use, tree stmt, ssa_imm_use_t *old)
 367 {
 368   v_def_use_operand_type_t *ptr;
 369   ptr = &(v_may_def_ops->v_may_defs[x]);
 370   ptr->def = def;
 371   ptr->use = use;
 372   ptr->imm_use.use = &(ptr->use);
 373   if (old)
 374     relink_imm_use_stmt (&(ptr->imm_use), old, stmt);
 375   else
 376     link_imm_use_stmt (&(ptr->imm_use), ptr->use, stmt);
 377 }
 378
 379
 380 /* Initialize V_MUST_DEF_OPS index X to be DEF = MUST_DEF <USE> for STMT.  If
 381    OLD is present, preserve the position of the may-def in the immediate_use
 382    list.  */
 383
 384 static inline void
 385 initialize_v_must_def_operand (v_must_def_optype v_must_def_ops, unsigned int x,
 386                               tree def, tree use, tree stmt, ssa_imm_use_t *old)
 387 {
 388   v_def_use_operand_type_t *ptr;
 389   ptr = &(v_must_def_ops->v_must_defs[x]);
 390   ptr->def = def;
 391   ptr->use = use;
 392   ptr->imm_use.use = &(ptr->use);
 393   if (old)
 394     relink_imm_use_stmt (&(ptr->imm_use), old, stmt);
 395   else
 396     link_imm_use_stmt (&(ptr->imm_use), ptr->use, stmt);
 397 }
 398
 399 /* All the finalize_ssa_* routines do the work required to turn the build_
 400    VARRAY into an operand_vector of the appropriate type.  The original vector,
 401    if any, is passed in for comparison and virtual SSA_NAME reuse.  If the
 402    old vector is reused, the pointer passed in is set to NULL so that
 403    the memory is not freed when the old operands are freed.  */
 404
 405 /* Return a new def operand vector for STMT, comparing to OLD_OPS_P.  */
 406
 407 static def_optype
 408 finalize_ssa_defs (def_optype *old_ops_p, tree stmt)
 409 {
 410   unsigned num, x;
 411   def_optype def_ops, old_ops;
 412   bool build_diff;
 413
 414   num = VARRAY_ACTIVE_SIZE (build_defs);
 415   if (num == 0)
 416     return NULL;
 417
 418   /* There should only be a single real definition per assignment.  */
 419   gcc_assert ((stmt && TREE_CODE (stmt) != MODIFY_EXPR) || num <= 1);
 420
 421   old_ops = *old_ops_p;
 422
 423   /* Compare old vector and new array.  */
 424   build_diff = true;
 425   if (stmt && old_ops && old_ops->num_defs == num)
 426     {
 427       build_diff = false;
 428       for (x = 0; x < num; x++)
 429         if (old_ops->defs[x].def != VARRAY_TREE_PTR (build_defs, x))
 430           {
 431             build_diff = true;
 432             break;
 433           }
 434     }
 435
 436   if (!build_diff)
 437     {
 438       def_ops = old_ops;
 439       *old_ops_p = NULL;
 440     }
 441   else
 442     {
 443       def_ops = allocate_def_optype (num);
 444       for (x = 0; x < num ; x++)
 445         def_ops->defs[x].def = VARRAY_TREE_PTR (build_defs, x);
 446     }
 447
 448   VARRAY_POP_ALL (build_defs);
 449
 450   return def_ops;
 451 }
 452
 453
 454 /* Make sure PTR is inn the correct immediate use list.  Since uses are simply
 455    pointers into the stmt TREE, there is no way of telling if anyone has
 456    changed what this pointer points to via TREE_OPERANDS (exp, 0) = <...>.
 457    THe contents are different, but the the pointer is still the same.  This
 458    routine will check to make sure PTR is in the correct list, and if it isn't
 459    put it in the correct list.  We cannot simply check the previous node
 460    because all nodes in the same stmt might have be changed.  */
 461
 462 static inline void
 463 correct_use_link (ssa_imm_use_t *ptr, tree stmt)
 464 {
 465   ssa_imm_use_t *prev;
 466   tree root;
 467
 468   /*  Fold_stmt () may have changed the stmt pointers.  */
 469   if (ptr->stmt != stmt)
 470     ptr->stmt = stmt;
 471
 472   prev = ptr->prev;
 473   if (prev)
 474     {
 475       bool stmt_mod = true;
 476       /* Find the first element which isn't a SAFE iterator, is in a sifferent
 477          stmt, and is not a a modified stmt,  That node is in the correct list,
 478          see if we are too.  */
 479
 480       while (stmt_mod)
 481         {
 482           while (prev->stmt == stmt || prev->stmt == NULL)
 483             prev = prev->prev;
 484           if (prev->use == NULL)
 485             stmt_mod = false;
 486           else
 487             if ((stmt_mod = stmt_modified_p (prev->stmt)))
 488               prev = prev->prev;
 489         }
 490
 491       /* Get the ssa_name of the list the node is in.  */
 492       if (prev->use == NULL)
 493         root = prev->stmt;
 494       else
 495         root = *(prev->use);
 496       /* If its the right list, simply return.  */
 497       if (root == *(ptr->use))
 498         return;
 499     }
 500   /* Its in the wrong list if we reach here.  */
 501   delink_imm_use (ptr);
 502   link_imm_use (ptr, *(ptr->use));
 503 }
 504
 505
 506 /* Return a new use operand vector for STMT, comparing to OLD_OPS_P.  */
 507
 508 static use_optype
 509 finalize_ssa_uses (use_optype *old_ops_p, tree stmt)
 510 {
 511   unsigned num, x, num_old, i;
 512   use_optype use_ops, old_ops;
 513   bool build_diff;
 514
 515   num = VARRAY_ACTIVE_SIZE (build_uses);
 516   if (num == 0)
 517     return NULL;
 518
 519 #ifdef ENABLE_CHECKING
 520   {
 521     unsigned x;
 522     /* If the pointer to the operand is the statement itself, something is
 523        wrong.  It means that we are pointing to a local variable (the
 524        initial call to get_stmt_operands does not pass a pointer to a
 525        statement).  */
 526     for (x = 0; x < num; x++)
 527       gcc_assert (*(VARRAY_TREE_PTR (build_uses, x)) != stmt);
 528   }
 529 #endif
 530   old_ops = *old_ops_p;
 531   num_old = ((stmt && old_ops) ? old_ops->num_uses : 0);
 532
 533   /* Check if the old vector and the new array are the same.  */
 534   build_diff = true;
 535   if (stmt && old_ops && num_old == num)
 536     {
 537       build_diff = false;
 538       for (x = 0; x < num; x++)
 539         {
 540           tree *var_p = VARRAY_TREE_PTR (build_uses, x);
 541           tree *node = old_ops->uses[x].use;
 542           /* Check the pointer values to see if they are the same. */
 543           if (node != var_p)
 544             {
 545               build_diff = true;
 546               break;
 547             }
 548         }
 549     }
 550
 551   if (!build_diff)
 552     {
 553       use_ops = old_ops;
 554       *old_ops_p = NULL;
 555       for (i = 0; i < num_old; i++)
 556         correct_use_link (&(use_ops->uses[i]), stmt);
 557     }
 558   else
 559     {
 560       use_ops = allocate_use_optype (num);
 561       for (x = 0; x < num ; x++)
 562         {
 563           tree *var = VARRAY_TREE_PTR (build_uses, x);
 564           use_ops->uses[x].use = var;
 565           for (i = 0; i < num_old; i++)
 566             {
 567               ssa_imm_use_t *ptr = &(old_ops->uses[i]);
 568               if (ptr->use == var)
 569                 {
 570                   relink_imm_use_stmt (&(use_ops->uses[x]), ptr, stmt);
 571                   correct_use_link (&(use_ops->uses[x]), stmt);
 572                   break;
 573                 }
 574             }
 575           if (i == num_old)
 576             link_imm_use_stmt (&(use_ops->uses[x]), *var, stmt);
 577         }
 578     }
 579   VARRAY_POP_ALL (build_uses);
 580
 581   return use_ops;
 582 }
 583
 584
 585 /* Return a new v_may_def operand vector for STMT, comparing to OLD_OPS_P.  */
 586
 587 static v_may_def_optype
 588 finalize_ssa_v_may_defs (v_may_def_optype *old_ops_p, tree stmt)
 589 {
 590   unsigned num, x, i, old_num;
 591   v_may_def_optype v_may_def_ops, old_ops;
 592   tree result, var;
 593   bool build_diff;
 594
 595   num = VARRAY_ACTIVE_SIZE (build_v_may_defs);
 596   if (num == 0)
 597     return NULL;
 598
 599   old_ops = *old_ops_p;
 600
 601   /* Check if the old vector and the new array are the same.  */
 602   build_diff = true;
 603   if (stmt && old_ops && old_ops->num_v_may_defs == num)
 604     {
 605       old_num = num;
 606       build_diff = false;
 607       for (x = 0; x < num; x++)
 608         {
 609           var = old_ops->v_may_defs[x].def;
 610           if (TREE_CODE (var) == SSA_NAME)
 611             var = SSA_NAME_VAR (var);
 612           if (var != VARRAY_TREE (build_v_may_defs, x))
 613             {
 614               build_diff = true;
 615               break;
 616             }
 617         }
 618     }
 619   else
 620     old_num = (old_ops ? old_ops->num_v_may_defs : 0);
 621
 622   if (!build_diff)
 623     {
 624       v_may_def_ops = old_ops;
 625       *old_ops_p = NULL;
 626       for (x = 0; x < num; x++)
 627         correct_use_link (&(v_may_def_ops->v_may_defs[x].imm_use), stmt);
 628     }
 629   else
 630     {
 631       v_may_def_ops = allocate_v_may_def_optype (num);
 632       for (x = 0; x < num; x++)
 633         {
 634           var = VARRAY_TREE (build_v_may_defs, x);
 635           /* Look for VAR in the old operands vector.  */
 636           for (i = 0; i < old_num; i++)
 637             {
 638               result = old_ops->v_may_defs[i].def;
 639               if (TREE_CODE (result) == SSA_NAME)
 640                 result = SSA_NAME_VAR (result);
 641               if (result == var)
 642                 {
 643                   initialize_v_may_def_operand (v_may_def_ops, x,
 644                                                 old_ops->v_may_defs[i].def,
 645                                                 old_ops->v_may_defs[i].use,
 646                                                 stmt,
 647                                                 &(old_ops->v_may_defs[i].imm_use));
 648                   break;
 649                 }
 650             }
 651           if (i == old_num)
 652             {
 653               initialize_v_may_def_operand (v_may_def_ops, x, var, var, stmt,
 654                                             NULL);
 655             }
 656         }
 657     }
 658
 659   /* Empty the V_MAY_DEF build vector after VUSES have been processed.  */
 660
 661   return v_may_def_ops;
 662 }
 663
 664
 665 /* Clear the in_list bits and empty the build array for v_may_defs.  */
 666
 667 static inline void
 668 cleanup_v_may_defs (void)
 669 {
 670   unsigned x, num;
 671   num = VARRAY_ACTIVE_SIZE (build_v_may_defs);
 672
 673   for (x = 0; x < num; x++)
 674     {
 675       tree t = VARRAY_TREE (build_v_may_defs, x);
 676       var_ann_t ann = var_ann (t);
 677       ann->in_v_may_def_list = 0;
 678     }
 679   VARRAY_POP_ALL (build_v_may_defs);
 680 }
 681
 682 /* Return a new vuse operand vector, comparing to OLD_OPS_P.  */
 683
 684 static vuse_optype
 685 finalize_ssa_vuses (vuse_optype *old_ops_p, tree stmt)
 686 {
 687   unsigned num, x, i, num_v_may_defs, old_num;
 688   vuse_optype vuse_ops, old_ops;
 689   bool build_diff;
 690
 691   num = VARRAY_ACTIVE_SIZE (build_vuses);
 692   if (num == 0)
 693     {
 694       cleanup_v_may_defs ();
 695       return NULL;
 696     }
 697
 698   /* Remove superfluous VUSE operands.  If the statement already has a
 699    V_MAY_DEF operation for a variable 'a', then a VUSE for 'a' is not
 700    needed because V_MAY_DEFs imply a VUSE of the variable.  For instance,
 701    suppose that variable 'a' is aliased:
 702
 703               # VUSE <a_2>
 704               # a_3 = V_MAY_DEF <a_2>
 705               a = a + 1;
 706
 707   The VUSE <a_2> is superfluous because it is implied by the V_MAY_DEF
 708   operation.  */
 709
 710   num_v_may_defs = VARRAY_ACTIVE_SIZE (build_v_may_defs);
 711
 712   if (num_v_may_defs > 0)
 713     {
 714       size_t i;
 715       tree vuse;
 716       for (i = 0; i < VARRAY_ACTIVE_SIZE (build_vuses); i++)
 717         {
 718           vuse = VARRAY_TREE (build_vuses, i);
 719           if (TREE_CODE (vuse) != SSA_NAME)
 720             {
 721               var_ann_t ann = var_ann (vuse);
 722               ann->in_vuse_list = 0;
 723               if (ann->in_v_may_def_list)
 724                 {
 725                   /* If we found a useless VUSE operand, remove it from the
 726                      operand array by replacing it with the last active element
 727                      in the operand array (unless the useless VUSE was the
 728                      last operand, in which case we simply remove it.  */
 729                   if (i != VARRAY_ACTIVE_SIZE (build_vuses) - 1)
 730                     {
 731                       VARRAY_TREE (build_vuses, i)
 732                         = VARRAY_TREE (build_vuses,
 733                                        VARRAY_ACTIVE_SIZE (build_vuses) - 1);
 734                     }
 735                   VARRAY_POP (build_vuses);
 736
 737                   /* We want to rescan the element at this index, unless
 738                      this was the last element, in which case the loop
 739                      terminates.  */
 740                   i--;
 741                 }
 742             }
 743         }
 744     }
 745   else
 746     /* Clear out the in_list bits.  */
 747     for (x = 0; x < num; x++)
 748       {
 749         tree t = VARRAY_TREE (build_vuses, x);
 750         if (TREE_CODE (t) != SSA_NAME)
 751           {
 752             var_ann_t ann = var_ann (t);
 753             ann->in_vuse_list = 0;
 754           }
 755       }
 756
 757
 758   num = VARRAY_ACTIVE_SIZE (build_vuses);
 759   /* We could have reduced the size to zero now, however.  */
 760   if (num == 0)
 761     {
 762       cleanup_v_may_defs ();
 763       return NULL;
 764     }
 765
 766   old_ops = *old_ops_p;
 767
 768   /* Determine whether vuses is the same as the old vector.  */
 769   build_diff = true;
 770   if (stmt && old_ops && old_ops->num_vuses == num)
 771     {
 772       old_num = num;
 773       build_diff = false;
 774       for (x = 0; x < num ; x++)
 775         {
 776           tree v;
 777           v = old_ops->vuses[x].use;
 778           if (TREE_CODE (v) == SSA_NAME)
 779             v = SSA_NAME_VAR (v);
 780           if (v != VARRAY_TREE (build_vuses, x))
 781             {
 782               build_diff = true;
 783               break;
 784             }
 785         }
 786     }
 787   else
 788     old_num = (old_ops ? old_ops->num_vuses : 0);
 789
 790   if (!build_diff)
 791     {
 792       vuse_ops = old_ops;
 793       *old_ops_p = NULL;
 794       for (x = 0; x < num; x++)
 795         correct_use_link (&(vuse_ops->vuses[x].imm_use), stmt);
 796     }
 797   else
 798     {
 799       vuse_ops = allocate_vuse_optype (num);
 800       for (x = 0; x < num; x++)
 801         {
 802           tree result, var = VARRAY_TREE (build_vuses, x);
 803           /* Look for VAR in the old vector, and use that SSA_NAME.  */
 804           for (i = 0; i < old_num; i++)
 805             {
 806               result = old_ops->vuses[i].use;
 807               if (TREE_CODE (result) == SSA_NAME)
 808                 result = SSA_NAME_VAR (result);
 809               if (result == var)
 810                 {
 811                   initialize_vuse_operand (vuse_ops, x, old_ops->vuses[i].use,
 812                                            stmt, &(old_ops->vuses[i].imm_use));
 813                   break;
 814                 }
 815             }
 816           if (i == old_num)
 817             initialize_vuse_operand (vuse_ops, x, var, stmt, NULL);
 818         }
 819     }
 820
 821   /* The v_may_def build vector wasn't freed because we needed it here.
 822      Free it now with the vuses build vector.  */
 823   VARRAY_POP_ALL (build_vuses);
 824   cleanup_v_may_defs ();
 825
 826   return vuse_ops;
 827 }
 828
 829 /* Return a new v_must_def operand vector for STMT, comparing to OLD_OPS_P.  */
 830
 831 static v_must_def_optype
 832 finalize_ssa_v_must_defs (v_must_def_optype *old_ops_p, tree stmt)
 833 {
 834   unsigned num, x, i, old_num = 0;
 835   v_must_def_optype v_must_def_ops, old_ops;
 836   tree result, var;
 837   bool build_diff;
 838
 839   num = VARRAY_ACTIVE_SIZE (build_v_must_defs);
 840   if (num == 0)
 841     return NULL;
 842
 843   /* In the presence of subvars, there may be more than one V_MUST_DEF per
 844      statement (one for each subvar).  It is a bit expensive to verify that
 845      all must-defs in a statement belong to subvars if there is more than one
 846      MUST-def, so we don't do it.  Suffice to say, if you reach here without
 847      having subvars, and have num >1, you have hit a bug. */
 848
 849
 850   old_ops = *old_ops_p;
 851
 852   /* Check if the old vector and the new array are the same.  */
 853   build_diff = true;
 854   if (stmt && old_ops && old_ops->num_v_must_defs == num)
 855     {
 856       old_num = num;
 857       build_diff = false;
 858       for (x = 0; x < num; x++)
 859         {
 860           tree var = old_ops->v_must_defs[x].def;
 861           if (TREE_CODE (var) == SSA_NAME)
 862             var = SSA_NAME_VAR (var);
 863           if (var != VARRAY_TREE (build_v_must_defs, x))
 864             {
 865               build_diff = true;
 866               break;
 867             }
 868         }
 869     }
 870   else
 871     old_num = (old_ops ? old_ops->num_v_must_defs : 0);
 872
 873   if (!build_diff)
 874     {
 875       v_must_def_ops = old_ops;
 876       *old_ops_p = NULL;
 877       for (x = 0; x < num; x++)
 878         correct_use_link (&(v_must_def_ops->v_must_defs[x].imm_use), stmt);
 879     }
 880   else
 881     {
 882       v_must_def_ops = allocate_v_must_def_optype (num);
 883       for (x = 0; x < num ; x++)
 884         {
 885           var = VARRAY_TREE (build_v_must_defs, x);
 886           /* Look for VAR in the original vector.  */
 887           for (i = 0; i < old_num; i++)
 888             {
 889               result = old_ops->v_must_defs[i].def;
 890               if (TREE_CODE (result) == SSA_NAME)
 891                 result = SSA_NAME_VAR (result);
 892               if (result == var)
 893                 {
 894                   initialize_v_must_def_operand (v_must_def_ops, x,
 895                                                  old_ops->v_must_defs[i].def,
 896                                                  old_ops->v_must_defs[i].use,
 897                                                  stmt,
 898                                                  &(old_ops->v_must_defs[i].imm_use));
 899                   break;
 900                 }
 901             }
 902           if (i == old_num)
 903             {
 904               initialize_v_must_def_operand (v_must_def_ops, x, var, var, stmt,
 905                                              NULL);
 906             }
 907         }
 908     }
 909   VARRAY_POP_ALL (build_v_must_defs);
 910
 911   return v_must_def_ops;
 912 }
 913
 914
 915 /* Finalize all the build vectors, fill the new ones into INFO.  */
 916
 917 static inline void
 918 finalize_ssa_stmt_operands (tree stmt, stmt_operands_p old_ops,
 919                             stmt_operands_p new_ops)
 920 {
 921   new_ops->def_ops = finalize_ssa_defs (&(old_ops->def_ops), stmt);
 922   new_ops->use_ops = finalize_ssa_uses (&(old_ops->use_ops), stmt);
 923   new_ops->v_must_def_ops
 924     = finalize_ssa_v_must_defs (&(old_ops->v_must_def_ops), stmt);
 925   new_ops->v_may_def_ops
 926     = finalize_ssa_v_may_defs (&(old_ops->v_may_def_ops), stmt);
 927   new_ops->vuse_ops = finalize_ssa_vuses (&(old_ops->vuse_ops), stmt);
 928 }
 929
 930
 931 /* Start the process of building up operands vectors in INFO.  */
 932
 933 static inline void
 934 start_ssa_stmt_operands (void)
 935 {
 936   gcc_assert (VARRAY_ACTIVE_SIZE (build_defs) == 0);
 937   gcc_assert (VARRAY_ACTIVE_SIZE (build_uses) == 0);
 938   gcc_assert (VARRAY_ACTIVE_SIZE (build_vuses) == 0);
 939   gcc_assert (VARRAY_ACTIVE_SIZE (build_v_may_defs) == 0);
 940   gcc_assert (VARRAY_ACTIVE_SIZE (build_v_must_defs) == 0);
 941 }
 942
 943
 944 /* Add DEF_P to the list of pointers to operands.  */
 945
 946 static inline void
 947 append_def (tree *def_p)
 948 {
 949   VARRAY_PUSH_TREE_PTR (build_defs, def_p);
 950 }
 951
 952
 953 /* Add USE_P to the list of pointers to operands.  */
 954
 955 static inline void
 956 append_use (tree *use_p)
 957 {
 958   VARRAY_PUSH_TREE_PTR (build_uses, use_p);
 959 }
 960
 961
 962 /* Add a new virtual may def for variable VAR to the build array.  */
 963
 964 static inline void
 965 append_v_may_def (tree var)
 966 {
 967   var_ann_t ann = get_var_ann (var);
 968
 969   /* Don't allow duplicate entries.  */
 970   if (ann->in_v_may_def_list)
 971     return;
 972   ann->in_v_may_def_list = 1;
 973
 974   VARRAY_PUSH_TREE (build_v_may_defs, var);
 975 }
 976
 977
 978 /* Add VAR to the list of virtual uses.  */
 979
 980 static inline void
 981 append_vuse (tree var)
 982 {
 983
 984   /* Don't allow duplicate entries.  */
 985   if (TREE_CODE (var) != SSA_NAME)
 986     {
 987       var_ann_t ann = get_var_ann (var);
 988
 989       if (ann->in_vuse_list || ann->in_v_may_def_list)
 990         return;
 991       ann->in_vuse_list = 1;
 992     }
 993
 994   VARRAY_PUSH_TREE (build_vuses, var);
 995 }
 996
 997
 998 /* Add VAR to the list of virtual must definitions for INFO.  */
 999
1000 static inline void
1001 append_v_must_def (tree var)
1002 {
1003   unsigned i;
1004
1005   /* Don't allow duplicate entries.  */
1006   for (i = 0; i < VARRAY_ACTIVE_SIZE (build_v_must_defs); i++)
1007     if (var == VARRAY_TREE (build_v_must_defs, i))
1008       return;
1009
1010   VARRAY_PUSH_TREE (build_v_must_defs, var);
1011 }
1012
1013
1014 /* Parse STMT looking for operands.  OLD_OPS is the original stmt operand
1015    cache for STMT, if it existed before.  When finished, the various build_*
1016    operand vectors will have potential operands. in them.  */
1017
1018 static void
1019 parse_ssa_operands (tree stmt)
1020 {
1021   enum tree_code code;
1022
1023   code = TREE_CODE (stmt);
1024   switch (code)
1025     {
1026     case MODIFY_EXPR:
1027       /* First get operands from the RHS.  For the LHS, we use a V_MAY_DEF if
1028          either only part of LHS is modified or if the RHS might throw,
1029          otherwise, use V_MUST_DEF.
1030
1031          ??? If it might throw, we should represent somehow that it is killed
1032          on the fallthrough path.  */
1033       {
1034         tree lhs = TREE_OPERAND (stmt, 0);
1035         int lhs_flags = opf_is_def;
1036
1037         get_expr_operands (stmt, &TREE_OPERAND (stmt, 1), opf_none);
1038
1039         /* If the LHS is a VIEW_CONVERT_EXPR, it isn't changing whether
1040            or not the entire LHS is modified; that depends on what's
1041            inside the VIEW_CONVERT_EXPR.  */
1042         if (TREE_CODE (lhs) == VIEW_CONVERT_EXPR)
1043           lhs = TREE_OPERAND (lhs, 0);
1044
1045         if (TREE_CODE (lhs) != ARRAY_REF && TREE_CODE (lhs) != ARRAY_RANGE_REF
1046             && TREE_CODE (lhs) != BIT_FIELD_REF
1047             && TREE_CODE (lhs) != REALPART_EXPR
1048             && TREE_CODE (lhs) != IMAGPART_EXPR)
1049           lhs_flags |= opf_kill_def;
1050
1051         get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), lhs_flags);
1052       }
1053       break;
1054
1055     case COND_EXPR:
1056       get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_none);
1057       break;
1058
1059     case SWITCH_EXPR:
1060       get_expr_operands (stmt, &SWITCH_COND (stmt), opf_none);
1061       break;
1062
1063     case ASM_EXPR:
1064       get_asm_expr_operands (stmt);
1065       break;
1066
1067     case RETURN_EXPR:
1068       get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_none);
1069       break;
1070
1071     case GOTO_EXPR:
1072       get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_none);
1073       break;
1074
1075     case LABEL_EXPR:
1076       get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_none);
1077       break;
1078
1079       /* These nodes contain no variable references.  */
1080     case BIND_EXPR:
1081     case CASE_LABEL_EXPR:
1082     case TRY_CATCH_EXPR:
1083     case TRY_FINALLY_EXPR:
1084     case EH_FILTER_EXPR:
1085     case CATCH_EXPR:
1086     case RESX_EXPR:
1087       break;
1088
1089     default:
1090       /* Notice that if get_expr_operands tries to use &STMT as the operand
1091          pointer (which may only happen for USE operands), we will abort in
1092          append_use.  This default will handle statements like empty
1093          statements, or CALL_EXPRs that may appear on the RHS of a statement
1094          or as statements themselves.  */
1095       get_expr_operands (stmt, &stmt, opf_none);
1096       break;
1097     }
1098 }
1099
1100 /* Create an operands cache for STMT, returning it in NEW_OPS. OLD_OPS are the
1101    original operands, and if ANN is non-null, appropriate stmt flags are set
1102    in the stmt's annotation.  If ANN is NULL, this is not considered a "real"
1103    stmt, and none of the operands will be entered into their respective
1104    immediate uses tables.  This is to allow stmts to be processed when they
1105    are not actually in the CFG.
1106
1107    Note that some fields in old_ops may change to NULL, although none of the
1108    memory they originally pointed to will be destroyed.  It is appropriate
1109    to call free_stmt_operands() on the value returned in old_ops.
1110
1111    The rationale for this: Certain optimizations wish to examine the difference
1112    between new_ops and old_ops after processing.  If a set of operands don't
1113    change, new_ops will simply assume the pointer in old_ops, and the old_ops
1114    pointer will be set to NULL, indicating no memory needs to be cleared.
1115    Usage might appear something like:
1116
1117        old_ops_copy = old_ops = stmt_ann(stmt)->operands;
1118        build_ssa_operands (stmt, NULL, &old_ops, &new_ops);
1119           <* compare old_ops_copy and new_ops *>
1120        free_ssa_operands (old_ops);                                     */
1121
1122 static void
1123 build_ssa_operands (tree stmt, stmt_ann_t ann, stmt_operands_p old_ops,
1124                     stmt_operands_p new_ops)
1125 {
1126   tree_ann_t saved_ann = stmt->common.ann;
1127
1128   /* Replace stmt's annotation with the one passed in for the duration
1129      of the operand building process.  This allows "fake" stmts to be built
1130      and not be included in other data structures which can be built here.  */
1131   stmt->common.ann = (tree_ann_t) ann;
1132
1133   parse_old_ops = old_ops;
1134
1135   /* Initially assume that the statement has no volatile operands, nor
1136      makes aliased loads or stores.  */
1137   if (ann)
1138     {
1139       ann->has_volatile_ops = false;
1140       ann->makes_aliased_stores = false;
1141       ann->makes_aliased_loads = false;
1142     }
1143
1144   start_ssa_stmt_operands ();
1145
1146   parse_ssa_operands (stmt);
1147
1148   parse_old_ops = NULL;
1149
1150   if (ann)
1151     finalize_ssa_stmt_operands (stmt, old_ops, new_ops);
1152   else
1153     finalize_ssa_stmt_operands (NULL, old_ops, new_ops);
1154   stmt->common.ann = saved_ann;
1155 }
1156
1157
1158 /* Free any operands vectors in OPS.  */
1159
1160 static void
1161 free_ssa_operands (stmt_operands_p ops)
1162 {
1163   if (ops->def_ops)
1164     free_defs (&(ops->def_ops));
1165   if (ops->use_ops)
1166     free_uses (&(ops->use_ops));
1167   if (ops->vuse_ops)
1168     free_vuses (&(ops->vuse_ops));
1169   if (ops->v_may_def_ops)
1170     free_v_may_defs (&(ops->v_may_def_ops));
1171   if (ops->v_must_def_ops)
1172     free_v_must_defs (&(ops->v_must_def_ops));
1173 }
1174
1175
1176 /* Swap operands EXP0 and EXP1 in STMT.  */
1177
1178 static void
1179 swap_tree_operands (tree *exp0, tree *exp1)
1180 {
1181   tree op0, op1;
1182   op0 = *exp0;
1183   op1 = *exp1;
1184
1185   /* If the operand cache is active, attempt to preserve the relative positions
1186      of these two operands in their respective immediate use lists.  */
1187   if (build_defs != NULL && op0 != op1 && parse_old_ops != NULL)
1188     {
1189       unsigned x, use0, use1;
1190       use_optype uses = parse_old_ops->use_ops;
1191       use0 = use1 = NUM_USES (uses);
1192       /* Find the 2 operands in the cache, if they are there.  */
1193       for (x = 0; x < NUM_USES (uses); x++)
1194         if (USE_OP_PTR (uses, x)->use == exp0)
1195           {
1196             use0 = x;
1197             break;
1198           }
1199       for (x = 0; x < NUM_USES (uses); x++)
1200         if (USE_OP_PTR (uses, x)->use == exp1)
1201           {
1202             use1 = x;
1203             break;
1204           }
1205       /* If both uses don't have operand entries, there isnt much we can do
1206          at this point. Presumably we dont need to worry about it.  */
1207       if (use0 != NUM_USES (uses) && use1 != NUM_USES (uses))
1208         {
1209           tree *tmp = USE_OP_PTR (uses, use1)->use;
1210           gcc_assert (use0 != use1);
1211
1212           USE_OP_PTR (uses, use1)->use = USE_OP_PTR (uses, use0)->use;
1213           USE_OP_PTR (uses, use0)->use = tmp;
1214         }
1215     }
1216
1217   /* Now swap the data.  */
1218   *exp0 = op1;
1219   *exp1 = op0;
1220 }
1221
1222 /* Get the operands of statement STMT.  Note that repeated calls to
1223    get_stmt_operands for the same statement will do nothing until the
1224    statement is marked modified by a call to mark_stmt_modified().  */
1225
1226 void
1227 update_stmt_operands (tree stmt)
1228 {
1229   stmt_ann_t ann;
1230   stmt_operands_t old_operands;
1231
1232   /* If get_stmt_operands is called before SSA is initialized, dont
1233   do anything.  */
1234   if (build_defs == NULL)
1235     return;
1236   /* The optimizers cannot handle statements that are nothing but a
1237      _DECL.  This indicates a bug in the gimplifier.  */
1238   gcc_assert (!SSA_VAR_P (stmt));
1239
1240   ann = get_stmt_ann (stmt);
1241
1242   gcc_assert (ann->modified);
1243
1244   timevar_push (TV_TREE_OPS);
1245
1246   old_operands = ann->operands;
1247   memset (&(ann->operands), 0, sizeof (stmt_operands_t));
1248
1249   build_ssa_operands (stmt, ann, &old_operands, &(ann->operands));
1250   free_ssa_operands (&old_operands);
1251
1252   /* Clear the modified bit for STMT.  Subsequent calls to
1253      get_stmt_operands for this statement will do nothing until the
1254      statement is marked modified by a call to mark_stmt_modified().  */
1255   ann->modified = 0;
1256
1257   timevar_pop (TV_TREE_OPS);
1258 }
1259
1260
1261 /* Recursively scan the expression pointed by EXPR_P in statement referred to
1262    by INFO.  FLAGS is one of the OPF_* constants modifying how to interpret the
1263    operands found.  */
1264
1265 static void
1266 get_expr_operands (tree stmt, tree *expr_p, int flags)
1267 {
1268   enum tree_code code;
1269   enum tree_code_class class;
1270   tree expr = *expr_p;
1271   stmt_ann_t s_ann = stmt_ann (stmt);
1272
1273   if (expr == NULL)
1274     return;
1275
1276   code = TREE_CODE (expr);
1277   class = TREE_CODE_CLASS (code);
1278
1279   switch (code)
1280     {
1281     case ADDR_EXPR:
1282       /* We could have the address of a component, array member,
1283          etc which has interesting variable references.  */
1284       /* Taking the address of a variable does not represent a
1285          reference to it, but the fact that the stmt takes its address will be
1286          of interest to some passes (e.g. alias resolution).  */
1287       add_stmt_operand (expr_p, s_ann, 0);
1288
1289       /* If the address is invariant, there may be no interesting variable
1290          references inside.  */
1291       if (is_gimple_min_invariant (expr))
1292         return;
1293
1294       /* There should be no VUSEs created, since the referenced objects are
1295          not really accessed.  The only operands that we should find here
1296          are ARRAY_REF indices which will always be real operands (GIMPLE
1297          does not allow non-registers as array indices).  */
1298       flags |= opf_no_vops;
1299
1300       get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1301       return;
1302
1303     case SSA_NAME:
1304     case VAR_DECL:
1305     case PARM_DECL:
1306     case RESULT_DECL:
1307     case CONST_DECL:
1308       {
1309         subvar_t svars;
1310
1311         /* Add the subvars for a variable if it has subvars, to DEFS or USES.
1312            Otherwise, add the variable itself.
1313            Whether it goes to USES or DEFS depends on the operand flags.  */
1314         if (var_can_have_subvars (expr)
1315             && (svars = get_subvars_for_var (expr)))
1316           {
1317             subvar_t sv;
1318             for (sv = svars; sv; sv = sv->next)
1319               add_stmt_operand (&sv->var, s_ann, flags);
1320           }
1321         else
1322           {
1323             add_stmt_operand (expr_p, s_ann, flags);
1324           }
1325         return;
1326       }
1327     case MISALIGNED_INDIRECT_REF:
1328       get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
1329       /* fall through */
1330
1331     case ALIGN_INDIRECT_REF:
1332     case INDIRECT_REF:
1333       get_indirect_ref_operands (stmt, expr, flags);
1334       return;
1335
1336     case ARRAY_REF:
1337     case ARRAY_RANGE_REF:
1338       /* Treat array references as references to the virtual variable
1339          representing the array.  The virtual variable for an ARRAY_REF
1340          is the VAR_DECL for the array.  */
1341
1342       /* Add the virtual variable for the ARRAY_REF to VDEFS or VUSES
1343          according to the value of IS_DEF.  Recurse if the LHS of the
1344          ARRAY_REF node is not a regular variable.  */
1345       if (SSA_VAR_P (TREE_OPERAND (expr, 0)))
1346         add_stmt_operand (expr_p, s_ann, flags);
1347       else
1348         get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1349
1350       get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none);
1351       get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none);
1352       get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_none);
1353       return;
1354
1355     case COMPONENT_REF:
1356     case REALPART_EXPR:
1357     case IMAGPART_EXPR:
1358       {
1359         tree ref;
1360         HOST_WIDE_INT offset, size;
1361         /* This component ref becomes an access to all of the subvariables
1362            it can touch,  if we can determine that, but *NOT* the real one.
1363            If we can't determine which fields we could touch, the recursion
1364            will eventually get to a variable and add *all* of its subvars, or
1365            whatever is the minimum correct subset.  */
1366
1367         ref = okay_component_ref_for_subvars (expr, &offset, &size);
1368         if (ref)
1369           {
1370             subvar_t svars = get_subvars_for_var (ref);
1371             subvar_t sv;
1372             for (sv = svars; sv; sv = sv->next)
1373               {
1374                 bool exact;
1375                 if (overlap_subvar (offset, size, sv, &exact))
1376                   {
1377                     if (exact)
1378                       flags &= ~opf_kill_def;
1379                     add_stmt_operand (&sv->var, s_ann, flags);
1380                   }
1381               }
1382           }
1383         else
1384           get_expr_operands (stmt, &TREE_OPERAND (expr, 0),
1385                              flags & ~opf_kill_def);
1386
1387         if (code == COMPONENT_REF)
1388           get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none);
1389         return;
1390       }
1391     case WITH_SIZE_EXPR:
1392       /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
1393          and an rvalue reference to its second argument.  */
1394       get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none);
1395       get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1396       return;
1397
1398     case CALL_EXPR:
1399       get_call_expr_operands (stmt, expr);
1400       return;
1401
1402     case COND_EXPR:
1403     case VEC_COND_EXPR:
1404       get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_none);
1405       get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none);
1406       get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none);
1407       return;
1408
1409     case MODIFY_EXPR:
1410       {
1411         int subflags;
1412         tree op;
1413
1414         get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_none);
1415
1416         op = TREE_OPERAND (expr, 0);
1417         if (TREE_CODE (op) == WITH_SIZE_EXPR)
1418           op = TREE_OPERAND (expr, 0);
1419         if (TREE_CODE (op) == ARRAY_REF
1420             || TREE_CODE (op) == ARRAY_RANGE_REF
1421             || TREE_CODE (op) == REALPART_EXPR
1422             || TREE_CODE (op) == IMAGPART_EXPR)
1423           subflags = opf_is_def;
1424         else
1425           subflags = opf_is_def | opf_kill_def;
1426
1427         get_expr_operands (stmt, &TREE_OPERAND (expr, 0), subflags);
1428         return;
1429       }
1430
1431     case CONSTRUCTOR:
1432       {
1433         /* General aggregate CONSTRUCTORs have been decomposed, but they
1434            are still in use as the COMPLEX_EXPR equivalent for vectors.  */
1435
1436         tree t;
1437         for (t = TREE_OPERAND (expr, 0); t ; t = TREE_CHAIN (t))
1438           get_expr_operands (stmt, &TREE_VALUE (t), opf_none);
1439
1440         return;
1441       }
1442
1443     case TRUTH_NOT_EXPR:
1444     case BIT_FIELD_REF:
1445     case VIEW_CONVERT_EXPR:
1446     do_unary:
1447       get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1448       return;
1449
1450     case TRUTH_AND_EXPR:
1451     case TRUTH_OR_EXPR:
1452     case TRUTH_XOR_EXPR:
1453     case COMPOUND_EXPR:
1454     case OBJ_TYPE_REF:
1455     case ASSERT_EXPR:
1456     do_binary:
1457       {
1458         tree op0 = TREE_OPERAND (expr, 0);
1459         tree op1 = TREE_OPERAND (expr, 1);
1460
1461         /* If it would be profitable to swap the operands, then do so to
1462            canonicalize the statement, enabling better optimization.
1463
1464            By placing canonicalization of such expressions here we
1465            transparently keep statements in canonical form, even
1466            when the statement is modified.  */
1467         if (tree_swap_operands_p (op0, op1, false))
1468           {
1469             /* For relationals we need to swap the operands
1470                and change the code.  */
1471             if (code == LT_EXPR
1472                 || code == GT_EXPR
1473                 || code == LE_EXPR
1474                 || code == GE_EXPR)
1475               {
1476                 TREE_SET_CODE (expr, swap_tree_comparison (code));
1477                 swap_tree_operands (&TREE_OPERAND (expr, 0),
1478                                     &TREE_OPERAND (expr, 1));
1479               }
1480
1481             /* For a commutative operator we can just swap the operands.  */
1482             else if (commutative_tree_code (code))
1483               {
1484                 swap_tree_operands (&TREE_OPERAND (expr, 0),
1485                                     &TREE_OPERAND (expr, 1));
1486               }
1487           }
1488
1489         get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1490         get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
1491         return;
1492       }
1493
1494     case REALIGN_LOAD_EXPR:
1495       {
1496         get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1497         get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
1498         get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
1499         return;
1500       }
1501
1502     case BLOCK:
1503     case FUNCTION_DECL:
1504     case EXC_PTR_EXPR:
1505     case FILTER_EXPR:
1506     case LABEL_DECL:
1507       /* Expressions that make no memory references.  */
1508       return;
1509
1510     default:
1511       if (class == tcc_unary)
1512         goto do_unary;
1513       if (class == tcc_binary || class == tcc_comparison)
1514         goto do_binary;
1515       if (class == tcc_constant || class == tcc_type)
1516         return;
1517     }
1518
1519   /* If we get here, something has gone wrong.  */
1520 #ifdef ENABLE_CHECKING
1521   fprintf (stderr, "unhandled expression in get_expr_operands():\n");
1522   debug_tree (expr);
1523   fputs ("\n", stderr);
1524   internal_error ("internal error");
1525 #endif
1526   gcc_unreachable ();
1527 }
1528
1529
1530 /* Scan operands in the ASM_EXPR stmt referred to in INFO.  */
1531
1532 static void
1533 get_asm_expr_operands (tree stmt)
1534 {
1535   stmt_ann_t s_ann = stmt_ann (stmt);
1536   int noutputs = list_length (ASM_OUTPUTS (stmt));
1537   const char **oconstraints
1538     = (const char **) alloca ((noutputs) * sizeof (const char *));
1539   int i;
1540   tree link;
1541   const char *constraint;
1542   bool allows_mem, allows_reg, is_inout;
1543
1544   for (i=0, link = ASM_OUTPUTS (stmt); link; ++i, link = TREE_CHAIN (link))
1545     {
1546       oconstraints[i] = constraint
1547         = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1548       parse_output_constraint (&constraint, i, 0, 0,
1549           &allows_mem, &allows_reg, &is_inout);
1550
1551       /* This should have been split in gimplify_asm_expr.  */
1552       gcc_assert (!allows_reg || !is_inout);
1553
1554       /* Memory operands are addressable.  Note that STMT needs the
1555          address of this operand.  */
1556       if (!allows_reg && allows_mem)
1557         {
1558           tree t = get_base_address (TREE_VALUE (link));
1559           if (t && DECL_P (t))
1560             note_addressable (t, s_ann);
1561         }
1562
1563       get_expr_operands (stmt, &TREE_VALUE (link), opf_is_def);
1564     }
1565
1566   for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
1567     {
1568       constraint
1569         = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1570       parse_input_constraint (&constraint, 0, 0, noutputs, 0,
1571           oconstraints, &allows_mem, &allows_reg);
1572
1573       /* Memory operands are addressable.  Note that STMT needs the
1574          address of this operand.  */
1575       if (!allows_reg && allows_mem)
1576         {
1577           tree t = get_base_address (TREE_VALUE (link));
1578           if (t && DECL_P (t))
1579             note_addressable (t, s_ann);
1580         }
1581
1582       get_expr_operands (stmt, &TREE_VALUE (link), 0);
1583     }
1584
1585
1586   /* Clobber memory for asm ("" : : : "memory");  */
1587   for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
1588     if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
1589       {
1590         unsigned i;
1591         bitmap_iterator bi;
1592
1593         /* Clobber all call-clobbered variables (or .GLOBAL_VAR if we
1594            decided to group them).  */
1595         if (global_var)
1596           add_stmt_operand (&global_var, s_ann, opf_is_def);
1597         else
1598           EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i, bi)
1599               {
1600                 tree var = referenced_var (i);
1601                 add_stmt_operand (&var, s_ann, opf_is_def);
1602               }
1603
1604         /* Now clobber all addressables.  */
1605         EXECUTE_IF_SET_IN_BITMAP (addressable_vars, 0, i, bi)
1606             {
1607               tree var = referenced_var (i);
1608
1609               /* Subvars are explicitly represented in this list, so
1610                  we don't need the original to be added to the clobber
1611                  ops, but the original *will* be in this list because
1612                  we keep the addressability of the original
1613                  variable up-to-date so we don't screw up the rest of
1614                  the backend.  */
1615               if (var_can_have_subvars (var)
1616                   && get_subvars_for_var (var) != NULL)
1617                 continue;
1618
1619               add_stmt_operand (&var, s_ann, opf_is_def);
1620             }
1621
1622         break;
1623       }
1624 }
1625
1626 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1627    ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.  */
1628
1629 static void
1630 get_indirect_ref_operands (tree stmt, tree expr, int flags)
1631 {
1632   tree *pptr = &TREE_OPERAND (expr, 0);
1633   tree ptr = *pptr;
1634   stmt_ann_t s_ann = stmt_ann (stmt);
1635
1636   /* Stores into INDIRECT_REF operands are never killing definitions.  */
1637   flags &= ~opf_kill_def;
1638
1639   if (SSA_VAR_P (ptr))
1640     {
1641       struct ptr_info_def *pi = NULL;
1642
1643       /* If PTR has flow-sensitive points-to information, use it.  */
1644       if (TREE_CODE (ptr) == SSA_NAME
1645           && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
1646           && pi->name_mem_tag)
1647         {
1648           /* PTR has its own memory tag.  Use it.  */
1649           add_stmt_operand (&pi->name_mem_tag, s_ann, flags);
1650         }
1651       else
1652         {
1653           /* If PTR is not an SSA_NAME or it doesn't have a name
1654              tag, use its type memory tag.  */
1655           var_ann_t v_ann;
1656
1657           /* If we are emitting debugging dumps, display a warning if
1658              PTR is an SSA_NAME with no flow-sensitive alias
1659              information.  That means that we may need to compute
1660              aliasing again.  */
1661           if (dump_file
1662               && TREE_CODE (ptr) == SSA_NAME
1663               && pi == NULL)
1664             {
1665               fprintf (dump_file,
1666                   "NOTE: no flow-sensitive alias info for ");
1667               print_generic_expr (dump_file, ptr, dump_flags);
1668               fprintf (dump_file, " in ");
1669               print_generic_stmt (dump_file, stmt, dump_flags);
1670             }
1671
1672           if (TREE_CODE (ptr) == SSA_NAME)
1673             ptr = SSA_NAME_VAR (ptr);
1674           v_ann = var_ann (ptr);
1675           if (v_ann->type_mem_tag)
1676             add_stmt_operand (&v_ann->type_mem_tag, s_ann, flags);
1677         }
1678     }
1679
1680   /* If a constant is used as a pointer, we can't generate a real
1681      operand for it but we mark the statement volatile to prevent
1682      optimizations from messing things up.  */
1683   else if (TREE_CODE (ptr) == INTEGER_CST)
1684     {
1685       if (s_ann)
1686         s_ann->has_volatile_ops = true;
1687       return;
1688     }
1689
1690   /* Everything else *should* have been folded elsewhere, but users
1691      are smarter than we in finding ways to write invalid code.  We
1692      cannot just abort here.  If we were absolutely certain that we
1693      do handle all valid cases, then we could just do nothing here.
1694      That seems optimistic, so attempt to do something logical... */
1695   else if ((TREE_CODE (ptr) == PLUS_EXPR || TREE_CODE (ptr) == MINUS_EXPR)
1696            && TREE_CODE (TREE_OPERAND (ptr, 0)) == ADDR_EXPR
1697            && TREE_CODE (TREE_OPERAND (ptr, 1)) == INTEGER_CST)
1698     {
1699       /* Make sure we know the object is addressable.  */
1700       pptr = &TREE_OPERAND (ptr, 0);
1701       add_stmt_operand (pptr, s_ann, 0);
1702
1703       /* Mark the object itself with a VUSE.  */
1704       pptr = &TREE_OPERAND (*pptr, 0);
1705       get_expr_operands (stmt, pptr, flags);
1706       return;
1707     }
1708
1709   /* Ok, this isn't even is_gimple_min_invariant.  Something's broke.  */
1710   else
1711     gcc_unreachable ();
1712
1713   /* Add a USE operand for the base pointer.  */
1714   get_expr_operands (stmt, pptr, opf_none);
1715 }
1716
1717 /* A subroutine of get_expr_operands to handle CALL_EXPR.  */
1718
1719 static void
1720 get_call_expr_operands (tree stmt, tree expr)
1721 {
1722   tree op;
1723   int call_flags = call_expr_flags (expr);
1724
1725   /* If aliases have been computed already, add V_MAY_DEF or V_USE
1726      operands for all the symbols that have been found to be
1727      call-clobbered.
1728
1729      Note that if aliases have not been computed, the global effects
1730      of calls will not be included in the SSA web. This is fine
1731      because no optimizer should run before aliases have been
1732      computed.  By not bothering with virtual operands for CALL_EXPRs
1733      we avoid adding superfluous virtual operands, which can be a
1734      significant compile time sink (See PR 15855).  */
1735   if (aliases_computed_p
1736       && !bitmap_empty_p (call_clobbered_vars)
1737       && !(call_flags & ECF_NOVOPS))
1738     {
1739       /* A 'pure' or a 'const' function never call-clobbers anything.
1740          A 'noreturn' function might, but since we don't return anyway
1741          there is no point in recording that.  */
1742       if (TREE_SIDE_EFFECTS (expr)
1743           && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1744         add_call_clobber_ops (stmt);
1745       else if (!(call_flags & ECF_CONST))
1746         add_call_read_ops (stmt);
1747     }
1748
1749   /* Find uses in the called function.  */
1750   get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_none);
1751
1752   for (op = TREE_OPERAND (expr, 1); op; op = TREE_CHAIN (op))
1753     get_expr_operands (stmt, &TREE_VALUE (op), opf_none);
1754
1755   get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_none);
1756
1757 }
1758
1759
1760 /* Add *VAR_P to the appropriate operand array for INFO.  FLAGS is as in
1761    get_expr_operands.  If *VAR_P is a GIMPLE register, it will be added to
1762    the statement's real operands, otherwise it is added to virtual
1763    operands.  */
1764
1765 static void
1766 add_stmt_operand (tree *var_p, stmt_ann_t s_ann, int flags)
1767 {
1768   bool is_real_op;
1769   tree var, sym;
1770   var_ann_t v_ann;
1771
1772   var = *var_p;
1773   STRIP_NOPS (var);
1774
1775   /* If the operand is an ADDR_EXPR, add its operand to the list of
1776      variables that have had their address taken in this statement.  */
1777   if (TREE_CODE (var) == ADDR_EXPR)
1778     {
1779       note_addressable (TREE_OPERAND (var, 0), s_ann);
1780       return;
1781     }
1782
1783   /* If the original variable is not a scalar, it will be added to the list
1784      of virtual operands.  In that case, use its base symbol as the virtual
1785      variable representing it.  */
1786   is_real_op = is_gimple_reg (var);
1787   if (!is_real_op && !DECL_P (var))
1788     var = get_virtual_var (var);
1789
1790   /* If VAR is not a variable that we care to optimize, do nothing.  */
1791   if (var == NULL_TREE || !SSA_VAR_P (var))
1792     return;
1793
1794   sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1795   v_ann = var_ann (sym);
1796
1797   /* Mark statements with volatile operands.  Optimizers should back
1798      off from statements having volatile operands.  */
1799   if (TREE_THIS_VOLATILE (sym) && s_ann)
1800     s_ann->has_volatile_ops = true;
1801
1802   /* If the variable cannot be modified and this is a V_MAY_DEF change
1803      it into a VUSE.  This happens when read-only variables are marked
1804      call-clobbered and/or aliased to writeable variables.  So we only
1805      check that this only happens on stores, and not writes to GIMPLE
1806      registers.
1807
1808      FIXME: The C++ FE is emitting assignments in the IL stream for
1809      read-only globals.  This is wrong, but for the time being disable
1810      this transformation on V_MUST_DEF operands (otherwise, we
1811      mis-optimize SPEC2000's eon).  */
1812   if ((flags & opf_is_def)
1813       && !(flags & opf_kill_def)
1814       && unmodifiable_var_p (var))
1815     {
1816       gcc_assert (!is_real_op);
1817       flags &= ~opf_is_def;
1818     }
1819
1820   if (is_real_op)
1821     {
1822       /* The variable is a GIMPLE register.  Add it to real operands.  */
1823       if (flags & opf_is_def)
1824         append_def (var_p);
1825       else
1826         append_use (var_p);
1827     }
1828   else
1829     {
1830       varray_type aliases;
1831
1832       /* The variable is not a GIMPLE register.  Add it (or its aliases) to
1833          virtual operands, unless the caller has specifically requested
1834          not to add virtual operands (used when adding operands inside an
1835          ADDR_EXPR expression).  */
1836       if (flags & opf_no_vops)
1837         return;
1838
1839       aliases = v_ann->may_aliases;
1840
1841       if (aliases == NULL)
1842         {
1843           /* The variable is not aliased or it is an alias tag.  */
1844           if (flags & opf_is_def)
1845             {
1846               if (flags & opf_kill_def)
1847                 {
1848                   /* Only regular variables or struct fields may get a
1849                      V_MUST_DEF operand.  */
1850                   gcc_assert (v_ann->mem_tag_kind == NOT_A_TAG
1851                               || v_ann->mem_tag_kind == STRUCT_FIELD);
1852                   /* V_MUST_DEF for non-aliased, non-GIMPLE register
1853                     variable definitions.  */
1854                   append_v_must_def (var);
1855                 }
1856               else
1857                 {
1858                   /* Add a V_MAY_DEF for call-clobbered variables and
1859                      memory tags.  */
1860                   append_v_may_def (var);
1861                 }
1862             }
1863           else
1864             {
1865               append_vuse (var);
1866               if (s_ann && v_ann->is_alias_tag)
1867                 s_ann->makes_aliased_loads = 1;
1868             }
1869         }
1870       else
1871         {
1872           size_t i;
1873
1874           /* The variable is aliased.  Add its aliases to the virtual
1875              operands.  */
1876           gcc_assert (VARRAY_ACTIVE_SIZE (aliases) != 0);
1877
1878           if (flags & opf_is_def)
1879             {
1880               bool added_may_defs_p = false;
1881
1882               /* If the variable is also an alias tag, add a virtual
1883                  operand for it, otherwise we will miss representing
1884                  references to the members of the variable's alias set.
1885                  This fixes the bug in gcc.c-torture/execute/20020503-1.c.  */
1886               if (v_ann->is_alias_tag)
1887                 {
1888                   added_may_defs_p = true;
1889                   append_v_may_def (var);
1890                 }
1891
1892               for (i = 0; i < VARRAY_ACTIVE_SIZE (aliases); i++)
1893                 {
1894                   /* While VAR may be modifiable, some of its aliases
1895                      may not be.  If that's the case, we don't really
1896                      need to add them a V_MAY_DEF for them.  */
1897                   tree alias = VARRAY_TREE (aliases, i);
1898
1899                   if (unmodifiable_var_p (alias))
1900                     append_vuse (alias);
1901                   else
1902                     {
1903                       append_v_may_def (alias);
1904                       added_may_defs_p = true;
1905                     }
1906                 }
1907
1908               if (s_ann && added_may_defs_p)
1909                 s_ann->makes_aliased_stores = 1;
1910             }
1911           else
1912             {
1913               /* Similarly, append a virtual uses for VAR itself, when
1914                  it is an alias tag.  */
1915               if (v_ann->is_alias_tag)
1916                 append_vuse (var);
1917
1918               for (i = 0; i < VARRAY_ACTIVE_SIZE (aliases); i++)
1919                 append_vuse (VARRAY_TREE (aliases, i));
1920
1921               if (s_ann)
1922                 s_ann->makes_aliased_loads = 1;
1923             }
1924         }
1925     }
1926 }
1927
1928
1929 /* Record that VAR had its address taken in the statement with annotations
1930    S_ANN.  */
1931
1932 static void
1933 note_addressable (tree var, stmt_ann_t s_ann)
1934 {
1935   tree ref;
1936   subvar_t svars;
1937   HOST_WIDE_INT offset;
1938   HOST_WIDE_INT size;
1939
1940   if (!s_ann)
1941     return;
1942
1943   /* If this is a COMPONENT_REF, and we know exactly what it touches, we only
1944      take the address of the subvariables it will touch.
1945      Otherwise, we take the address of all the subvariables, plus the real
1946      ones.  */
1947
1948   if (var && TREE_CODE (var) == COMPONENT_REF
1949       && (ref = okay_component_ref_for_subvars (var, &offset, &size)))
1950     {
1951       subvar_t sv;
1952       svars = get_subvars_for_var (ref);
1953
1954       if (s_ann->addresses_taken == NULL)
1955         s_ann->addresses_taken = BITMAP_GGC_ALLOC ();
1956
1957       for (sv = svars; sv; sv = sv->next)
1958         {
1959           if (overlap_subvar (offset, size, sv, NULL))
1960             bitmap_set_bit (s_ann->addresses_taken, var_ann (sv->var)->uid);
1961         }
1962       return;
1963     }
1964
1965   var = get_base_address (var);
1966   if (var && SSA_VAR_P (var))
1967     {
1968       if (s_ann->addresses_taken == NULL)
1969         s_ann->addresses_taken = BITMAP_GGC_ALLOC ();
1970
1971
1972       if (var_can_have_subvars (var)
1973           && (svars = get_subvars_for_var (var)))
1974         {
1975           subvar_t sv;
1976           for (sv = svars; sv; sv = sv->next)
1977             bitmap_set_bit (s_ann->addresses_taken, var_ann (sv->var)->uid);
1978         }
1979       else
1980         bitmap_set_bit (s_ann->addresses_taken, var_ann (var)->uid);
1981     }
1982 }
1983
1984 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1985    clobbered variables in the function.  */
1986
1987 static void
1988 add_call_clobber_ops (tree stmt)
1989 {
1990   unsigned i;
1991   tree t;
1992   bitmap_iterator bi;
1993   stmt_ann_t s_ann = stmt_ann (stmt);
1994   struct stmt_ann_d empty_ann;
1995
1996   /* Functions that are not const, pure or never return may clobber
1997      call-clobbered variables.  */
1998   if (s_ann)
1999     s_ann->makes_clobbering_call = true;
2000
2001   /* If we created .GLOBAL_VAR earlier, just use it.  See compute_may_aliases
2002      for the heuristic used to decide whether to create .GLOBAL_VAR or not.  */
2003   if (global_var)
2004     {
2005       add_stmt_operand (&global_var, s_ann, opf_is_def);
2006       return;
2007     }
2008
2009   /* If cache is valid, copy the elements into the build vectors.  */
2010   if (ssa_call_clobbered_cache_valid)
2011     {
2012       for (i = 0; i < VARRAY_ACTIVE_SIZE (clobbered_vuses); i++)
2013         {
2014           t = VARRAY_TREE (clobbered_vuses, i);
2015           gcc_assert (TREE_CODE (t) != SSA_NAME);
2016           var_ann (t)->in_vuse_list = 1;
2017           VARRAY_PUSH_TREE (build_vuses, t);
2018         }
2019       for (i = 0; i < VARRAY_ACTIVE_SIZE (clobbered_v_may_defs); i++)
2020         {
2021           t = VARRAY_TREE (clobbered_v_may_defs, i);
2022           gcc_assert (TREE_CODE (t) != SSA_NAME);
2023           var_ann (t)->in_v_may_def_list = 1;
2024           VARRAY_PUSH_TREE (build_v_may_defs, t);
2025         }
2026       if (s_ann)
2027         {
2028           s_ann->makes_aliased_loads = clobbered_aliased_loads;
2029           s_ann->makes_aliased_stores = clobbered_aliased_stores;
2030         }
2031       return;
2032     }
2033
2034   memset (&empty_ann, 0, sizeof (struct stmt_ann_d));
2035
2036   /* Add a V_MAY_DEF operand for every call clobbered variable.  */
2037   EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i, bi)
2038     {
2039       tree var = referenced_var (i);
2040       if (unmodifiable_var_p (var))
2041         add_stmt_operand (&var, &empty_ann, opf_none);
2042       else
2043         add_stmt_operand (&var, &empty_ann, opf_is_def);
2044     }
2045
2046   clobbered_aliased_loads = empty_ann.makes_aliased_loads;
2047   clobbered_aliased_stores = empty_ann.makes_aliased_stores;
2048
2049   /* Set the flags for a stmt's annotation.  */
2050   if (s_ann)
2051     {
2052       s_ann->makes_aliased_loads = empty_ann.makes_aliased_loads;
2053       s_ann->makes_aliased_stores = empty_ann.makes_aliased_stores;
2054     }
2055
2056   /* Prepare empty cache vectors.  */
2057   if (clobbered_v_may_defs)
2058     {
2059       VARRAY_POP_ALL (clobbered_vuses);
2060       VARRAY_POP_ALL (clobbered_v_may_defs);
2061     }
2062   else
2063     {
2064       VARRAY_TREE_INIT (clobbered_v_may_defs, 10, "clobbered_v_may_defs");
2065       VARRAY_TREE_INIT (clobbered_vuses, 10, "clobbered_vuses");
2066     }
2067
2068   /* Now fill the clobbered cache with the values that have been found.  */
2069   for (i = 0; i < VARRAY_ACTIVE_SIZE (build_vuses); i++)
2070     VARRAY_PUSH_TREE (clobbered_vuses, VARRAY_TREE (build_vuses, i));
2071   for (i = 0; i < VARRAY_ACTIVE_SIZE (build_v_may_defs); i++)
2072     VARRAY_PUSH_TREE (clobbered_v_may_defs, VARRAY_TREE (build_v_may_defs, i));
2073
2074   ssa_call_clobbered_cache_valid = true;
2075 }
2076
2077
2078 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
2079    function.  */
2080
2081 static void
2082 add_call_read_ops (tree stmt)
2083 {
2084   unsigned i;
2085   tree t;
2086   bitmap_iterator bi;
2087   stmt_ann_t s_ann = stmt_ann (stmt);
2088   struct stmt_ann_d empty_ann;
2089
2090   /* if the function is not pure, it may reference memory.  Add
2091      a VUSE for .GLOBAL_VAR if it has been created.  See add_referenced_var
2092      for the heuristic used to decide whether to create .GLOBAL_VAR.  */
2093   if (global_var)
2094     {
2095       add_stmt_operand (&global_var, s_ann, opf_none);
2096       return;
2097     }
2098
2099   /* If cache is valid, copy the elements into the build vector.  */
2100   if (ssa_ro_call_cache_valid)
2101     {
2102       for (i = 0; i < VARRAY_ACTIVE_SIZE (ro_call_vuses); i++)
2103         {
2104           t = VARRAY_TREE (ro_call_vuses, i);
2105           gcc_assert (TREE_CODE (t) != SSA_NAME);
2106           var_ann (t)->in_vuse_list = 1;
2107           VARRAY_PUSH_TREE (build_vuses, t);
2108         }
2109       if (s_ann)
2110         s_ann->makes_aliased_loads = ro_call_aliased_loads;
2111       return;
2112     }
2113
2114   memset (&empty_ann, 0, sizeof (struct stmt_ann_d));
2115
2116   /* Add a VUSE for each call-clobbered variable.  */
2117   EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i, bi)
2118     {
2119       tree var = referenced_var (i);
2120       add_stmt_operand (&var, &empty_ann, opf_none);
2121     }
2122
2123   ro_call_aliased_loads = empty_ann.makes_aliased_loads;
2124   if (s_ann)
2125     s_ann->makes_aliased_loads = empty_ann.makes_aliased_loads;
2126
2127   /* Prepare empty cache vectors.  */
2128   if (ro_call_vuses)
2129     VARRAY_POP_ALL (ro_call_vuses);
2130   else
2131     VARRAY_TREE_INIT (ro_call_vuses, 10, "ro_call_vuses");
2132
2133   /* Now fill the clobbered cache with the values that have been found.  */
2134   for (i = 0; i < VARRAY_ACTIVE_SIZE (build_vuses); i++)
2135     VARRAY_PUSH_TREE (ro_call_vuses, VARRAY_TREE (build_vuses, i));
2136
2137   ssa_ro_call_cache_valid = true;
2138 }
2139
2140 /* Copies virtual operands from SRC to DST.  */
2141
2142 void
2143 copy_virtual_operands (tree dst, tree src)
2144 {
2145   unsigned i;
2146   vuse_optype vuses = STMT_VUSE_OPS (src);
2147   v_may_def_optype v_may_defs = STMT_V_MAY_DEF_OPS (src);
2148   v_must_def_optype v_must_defs = STMT_V_MUST_DEF_OPS (src);
2149   vuse_optype *vuses_new = &stmt_ann (dst)->operands.vuse_ops;
2150   v_may_def_optype *v_may_defs_new = &stmt_ann (dst)->operands.v_may_def_ops;
2151   v_must_def_optype *v_must_defs_new = &stmt_ann (dst)->operands.v_must_def_ops;
2152
2153   if (vuses)
2154     {
2155       *vuses_new = allocate_vuse_optype (NUM_VUSES (vuses));
2156       for (i = 0; i < NUM_VUSES (vuses); i++)
2157         initialize_vuse_operand (*vuses_new, i, VUSE_OP (vuses, i), dst, NULL);
2158     }
2159
2160   if (v_may_defs)
2161     {
2162       *v_may_defs_new = allocate_v_may_def_optype (NUM_V_MAY_DEFS (v_may_defs));
2163       for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
2164         {
2165           initialize_v_may_def_operand (*v_may_defs_new, i,
2166                                         V_MAY_DEF_RESULT (v_may_defs, i),
2167                                         V_MAY_DEF_OP (v_may_defs, i), dst,
2168                                         NULL);
2169         }
2170     }
2171
2172   if (v_must_defs)
2173     {
2174       *v_must_defs_new
2175          = allocate_v_must_def_optype (NUM_V_MUST_DEFS (v_must_defs));
2176       for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++)
2177         {
2178           initialize_v_must_def_operand (*v_must_defs_new, i,
2179                                          V_MUST_DEF_RESULT (v_must_defs, i),
2180                                          V_MUST_DEF_KILL (v_must_defs, i), dst,
2181                                          NULL);
2182         }
2183     }
2184 }
2185
2186
2187 /* Specifically for use in DOM's expression analysis.  Given a store, we
2188    create an artificial stmt which looks like a load from the store, this can
2189    be used to eliminate redundant loads.  OLD_OPS are the operands from the
2190    store stmt, and NEW_STMT is the new load which represents a load of the
2191    values stored.  */
2192
2193 void
2194 create_ssa_artficial_load_stmt (stmt_operands_p old_ops, tree new_stmt)
2195 {
2196   stmt_ann_t ann;
2197   tree op;
2198   stmt_operands_t tmp;
2199   unsigned j;
2200
2201   memset (&tmp, 0, sizeof (stmt_operands_t));
2202   ann = get_stmt_ann (new_stmt);
2203
2204   /* Free operands just in case is was an existing stmt.  */
2205   free_ssa_operands (&(ann->operands));
2206
2207   build_ssa_operands (new_stmt, NULL, &tmp, &(ann->operands));
2208   free_vuses (&(ann->operands.vuse_ops));
2209   free_v_may_defs (&(ann->operands.v_may_def_ops));
2210   free_v_must_defs (&(ann->operands.v_must_def_ops));
2211
2212   /* For each VDEF on the original statement, we want to create a
2213      VUSE of the V_MAY_DEF result or V_MUST_DEF op on the new
2214      statement.  */
2215   for (j = 0; j < NUM_V_MAY_DEFS (old_ops->v_may_def_ops); j++)
2216     {
2217       op = V_MAY_DEF_RESULT (old_ops->v_may_def_ops, j);
2218       append_vuse (op);
2219     }
2220
2221   for (j = 0; j < NUM_V_MUST_DEFS (old_ops->v_must_def_ops); j++)
2222     {
2223       op = V_MUST_DEF_RESULT (old_ops->v_must_def_ops, j);
2224       append_vuse (op);
2225     }
2226
2227   /* Now set the vuses for this new stmt.  */
2228   ann->operands.vuse_ops = finalize_ssa_vuses (&(tmp.vuse_ops), NULL);
2229 }
2230
2231
2232
2233 /* Issue immediate use error for VAR to debug file F.  */
2234 static void
2235 verify_abort (FILE *f, ssa_imm_use_t *var)
2236 {
2237   tree stmt;
2238   stmt = var->stmt;
2239   if (stmt)
2240     {
2241       if (stmt_modified_p(stmt))
2242         {
2243           fprintf (f, " STMT MODIFIED. - <%p> ", (void *)stmt);
2244           print_generic_stmt (f, stmt, TDF_SLIM);
2245         }
2246     }
2247   fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)var,
2248            (void *)var->use);
2249   print_generic_expr (f, USE_FROM_PTR (var), TDF_SLIM);
2250   fprintf(f, "\n");
2251 }
2252
2253
2254 /* Scan the immediate_use list for VAR making sure its linked properly.
2255    return RTUE iof there is a problem.  */
2256
2257 bool
2258 verify_imm_links (FILE *f, tree var)
2259 {
2260   ssa_imm_use_t *ptr, *prev;
2261   ssa_imm_use_t *list;
2262   int count;
2263
2264   gcc_assert (TREE_CODE (var) == SSA_NAME);
2265
2266   list = &(SSA_NAME_IMM_USE_NODE (var));
2267   gcc_assert (list->use == NULL);
2268
2269   if (list->prev == NULL)
2270     {
2271       gcc_assert (list->next == NULL);
2272       return false;
2273     }
2274
2275   prev = list;
2276   count = 0;
2277   for (ptr = list->next; ptr != list; )
2278     {
2279       if (prev != ptr->prev)
2280         {
2281           verify_abort (f, ptr);
2282           return true;
2283         }
2284
2285       if (ptr->use == NULL)
2286         {
2287           verify_abort (f, ptr);        /* 2 roots, or SAFE guard node.  */
2288           return true;
2289         }
2290       else
2291         if (*(ptr->use) != var)
2292           {
2293             verify_abort (f, ptr);
2294             return true;
2295           }
2296
2297       prev = ptr;
2298       ptr = ptr->next;
2299       /* Avoid infinite loops.  */
2300       if (count++ > 30000)
2301         {
2302           verify_abort (f, ptr);
2303           return true;
2304         }
2305     }
2306
2307   /* Verify list in the other direction.  */
2308   prev = list;
2309   for (ptr = list->prev; ptr != list; )
2310     {
2311       if (prev != ptr->next)
2312         {
2313           verify_abort (f, ptr);
2314           return true;
2315         }
2316       prev = ptr;
2317       ptr = ptr->prev;
2318       if (count-- < 0)
2319         {
2320           verify_abort (f, ptr);
2321           return true;
2322         }
2323     }
2324
2325   if (count != 0)
2326     {
2327       verify_abort (f, ptr);
2328       return true;
2329     }
2330
2331   return false;
2332 }
2333
2334
2335 /* Dump all the immediate uses to FILE.  */
2336
2337 void
2338 dump_immediate_uses_for (FILE *file, tree var)
2339 {
2340   imm_use_iterator iter;
2341   use_operand_p use_p;
2342
2343   gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2344
2345   print_generic_expr (file, var, TDF_SLIM);
2346   fprintf (file, " : -->");
2347   if (has_zero_uses (var))
2348     fprintf (file, " no uses.\n");
2349   else
2350     if (has_single_use (var))
2351       fprintf (file, " single use.\n");
2352     else
2353       fprintf (file, "%d uses.\n", num_imm_uses (var));
2354
2355   FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2356     {
2357       print_generic_stmt (file, USE_STMT (use_p), TDF_SLIM);
2358     }
2359   fprintf(file, "\n");
2360 }
2361
2362 /* Dump all the immediate uses to FILE.  */
2363
2364 void
2365 dump_immediate_uses (FILE *file)
2366 {
2367   tree var;
2368   unsigned int x;
2369
2370   fprintf (file, "Immediate_uses: \n\n");
2371   for (x = 1; x < num_ssa_names; x++)
2372     {
2373       var = ssa_name(x);
2374       if (!var)
2375         continue;
2376       dump_immediate_uses_for (file, var);
2377     }
2378 }
2379
2380
2381 /* Dump def-use edges on stderr.  */
2382
2383 void
2384 debug_immediate_uses (void)
2385 {
2386   dump_immediate_uses (stderr);
2387 }
2388
2389 /* Dump def-use edges on stderr.  */
2390
2391 void
2392 debug_immediate_uses_for (tree var)
2393 {
2394   dump_immediate_uses_for (stderr, var);
2395 }
2396
2397 #include "gt-tree-ssa-operands.h"