gcc/tree-dfa.c

   1 /* Data flow functions for trees.
   2    Copyright (C) 2001-2018 Free Software Foundation, Inc.
   3    Contributed by Diego Novillo <dnovillo@redhat.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "backend.h"
  25 #include "rtl.h"
  26 #include "tree.h"
  27 #include "gimple.h"
  28 #include "tree-pass.h"
  29 #include "ssa.h"
  30 #include "tree-pretty-print.h"
  31 #include "fold-const.h"
  32 #include "stor-layout.h"
  33 #include "langhooks.h"
  34 #include "gimple-iterator.h"
  35 #include "gimple-walk.h"
  36 #include "tree-dfa.h"
  37
  38 /* Build and maintain data flow information for trees.  */
  39
  40 /* Counters used to display DFA and SSA statistics.  */
  41 struct dfa_stats_d
  42 {
  43   long num_defs;
  44   long num_uses;
  45   long num_phis;
  46   long num_phi_args;
  47   size_t max_num_phi_args;
  48   long num_vdefs;
  49   long num_vuses;
  50 };
  51
  52
  53 /* Local functions.  */
  54 static void collect_dfa_stats (struct dfa_stats_d *);
  55
  56
  57 /*---------------------------------------------------------------------------
  58                         Dataflow analysis (DFA) routines
  59 ---------------------------------------------------------------------------*/
  60
  61 /* Renumber all of the gimple stmt uids.  */
  62
  63 void
  64 renumber_gimple_stmt_uids (void)
  65 {
  66   basic_block bb;
  67
  68   set_gimple_stmt_max_uid (cfun, 0);
  69   FOR_ALL_BB_FN (bb, cfun)
  70     {
  71       gimple_stmt_iterator bsi;
  72       for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
  73         {
  74           gimple *stmt = gsi_stmt (bsi);
  75           gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
  76         }
  77       for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
  78         {
  79           gimple *stmt = gsi_stmt (bsi);
  80           gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
  81         }
  82     }
  83 }
  84
  85 /* Like renumber_gimple_stmt_uids, but only do work on the basic blocks
  86    in BLOCKS, of which there are N_BLOCKS.  Also renumbers PHIs.  */
  87
  88 void
  89 renumber_gimple_stmt_uids_in_blocks (basic_block *blocks, int n_blocks)
  90 {
  91   int i;
  92
  93   set_gimple_stmt_max_uid (cfun, 0);
  94   for (i = 0; i < n_blocks; i++)
  95     {
  96       basic_block bb = blocks[i];
  97       gimple_stmt_iterator bsi;
  98       for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
  99         {
 100           gimple *stmt = gsi_stmt (bsi);
 101           gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
 102         }
 103       for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
 104         {
 105           gimple *stmt = gsi_stmt (bsi);
 106           gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
 107         }
 108     }
 109 }
 110
 111
 112
 113 /*---------------------------------------------------------------------------
 114                               Debugging functions
 115 ---------------------------------------------------------------------------*/
 116
 117 /* Dump variable VAR and its may-aliases to FILE.  */
 118
 119 void
 120 dump_variable (FILE *file, tree var)
 121 {
 122   if (TREE_CODE (var) == SSA_NAME)
 123     {
 124       if (POINTER_TYPE_P (TREE_TYPE (var)))
 125         dump_points_to_info_for (file, var);
 126       var = SSA_NAME_VAR (var);
 127     }
 128
 129   if (var == NULL_TREE)
 130     {
 131       fprintf (file, "<nil>");
 132       return;
 133     }
 134
 135   print_generic_expr (file, var, dump_flags);
 136
 137   fprintf (file, ", UID D.%u", (unsigned) DECL_UID (var));
 138   if (DECL_PT_UID (var) != DECL_UID (var))
 139     fprintf (file, ", PT-UID D.%u", (unsigned) DECL_PT_UID (var));
 140
 141   fprintf (file, ", ");
 142   print_generic_expr (file, TREE_TYPE (var), dump_flags);
 143
 144   if (TREE_ADDRESSABLE (var))
 145     fprintf (file, ", is addressable");
 146
 147   if (is_global_var (var))
 148     fprintf (file, ", is global");
 149
 150   if (TREE_THIS_VOLATILE (var))
 151     fprintf (file, ", is volatile");
 152
 153   if (cfun && ssa_default_def (cfun, var))
 154     {
 155       fprintf (file, ", default def: ");
 156       print_generic_expr (file, ssa_default_def (cfun, var), dump_flags);
 157     }
 158
 159   if (DECL_INITIAL (var))
 160     {
 161       fprintf (file, ", initial: ");
 162       print_generic_expr (file, DECL_INITIAL (var), dump_flags);
 163     }
 164
 165   fprintf (file, "\n");
 166 }
 167
 168
 169 /* Dump variable VAR and its may-aliases to stderr.  */
 170
 171 DEBUG_FUNCTION void
 172 debug_variable (tree var)
 173 {
 174   dump_variable (stderr, var);
 175 }
 176
 177
 178 /* Dump various DFA statistics to FILE.  */
 179
 180 void
 181 dump_dfa_stats (FILE *file)
 182 {
 183   struct dfa_stats_d dfa_stats;
 184
 185   unsigned long size, total = 0;
 186   const char * const fmt_str   = "%-30s%-13s%12s\n";
 187   const char * const fmt_str_1 = "%-30s%13lu%11lu%c\n";
 188   const char * const fmt_str_3 = "%-43s%11lu%c\n";
 189   const char *funcname
 190     = lang_hooks.decl_printable_name (current_function_decl, 2);
 191
 192   collect_dfa_stats (&dfa_stats);
 193
 194   fprintf (file, "\nDFA Statistics for %s\n\n", funcname);
 195
 196   fprintf (file, "---------------------------------------------------------\n");
 197   fprintf (file, fmt_str, "", "  Number of  ", "Memory");
 198   fprintf (file, fmt_str, "", "  instances  ", "used ");
 199   fprintf (file, "---------------------------------------------------------\n");
 200
 201   size = dfa_stats.num_uses * sizeof (tree *);
 202   total += size;
 203   fprintf (file, fmt_str_1, "USE operands", dfa_stats.num_uses,
 204            SCALE (size), LABEL (size));
 205
 206   size = dfa_stats.num_defs * sizeof (tree *);
 207   total += size;
 208   fprintf (file, fmt_str_1, "DEF operands", dfa_stats.num_defs,
 209            SCALE (size), LABEL (size));
 210
 211   size = dfa_stats.num_vuses * sizeof (tree *);
 212   total += size;
 213   fprintf (file, fmt_str_1, "VUSE operands", dfa_stats.num_vuses,
 214            SCALE (size), LABEL (size));
 215
 216   size = dfa_stats.num_vdefs * sizeof (tree *);
 217   total += size;
 218   fprintf (file, fmt_str_1, "VDEF operands", dfa_stats.num_vdefs,
 219            SCALE (size), LABEL (size));
 220
 221   size = dfa_stats.num_phis * sizeof (struct gphi);
 222   total += size;
 223   fprintf (file, fmt_str_1, "PHI nodes", dfa_stats.num_phis,
 224            SCALE (size), LABEL (size));
 225
 226   size = dfa_stats.num_phi_args * sizeof (struct phi_arg_d);
 227   total += size;
 228   fprintf (file, fmt_str_1, "PHI arguments", dfa_stats.num_phi_args,
 229            SCALE (size), LABEL (size));
 230
 231   fprintf (file, "---------------------------------------------------------\n");
 232   fprintf (file, fmt_str_3, "Total memory used by DFA/SSA data", SCALE (total),
 233            LABEL (total));
 234   fprintf (file, "---------------------------------------------------------\n");
 235   fprintf (file, "\n");
 236
 237   if (dfa_stats.num_phis)
 238     fprintf (file, "Average number of arguments per PHI node: %.1f (max: %ld)\n",
 239              (float) dfa_stats.num_phi_args / (float) dfa_stats.num_phis,
 240              (long) dfa_stats.max_num_phi_args);
 241
 242   fprintf (file, "\n");
 243 }
 244
 245
 246 /* Dump DFA statistics on stderr.  */
 247
 248 DEBUG_FUNCTION void
 249 debug_dfa_stats (void)
 250 {
 251   dump_dfa_stats (stderr);
 252 }
 253
 254
 255 /* Collect DFA statistics and store them in the structure pointed to by
 256    DFA_STATS_P.  */
 257
 258 static void
 259 collect_dfa_stats (struct dfa_stats_d *dfa_stats_p ATTRIBUTE_UNUSED)
 260 {
 261   basic_block bb;
 262
 263   gcc_assert (dfa_stats_p);
 264
 265   memset ((void *)dfa_stats_p, 0, sizeof (struct dfa_stats_d));
 266
 267   /* Walk all the statements in the function counting references.  */
 268   FOR_EACH_BB_FN (bb, cfun)
 269     {
 270       for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si);
 271            gsi_next (&si))
 272         {
 273           gphi *phi = si.phi ();
 274           dfa_stats_p->num_phis++;
 275           dfa_stats_p->num_phi_args += gimple_phi_num_args (phi);
 276           if (gimple_phi_num_args (phi) > dfa_stats_p->max_num_phi_args)
 277             dfa_stats_p->max_num_phi_args = gimple_phi_num_args (phi);
 278         }
 279
 280       for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si);
 281            gsi_next (&si))
 282         {
 283           gimple *stmt = gsi_stmt (si);
 284           dfa_stats_p->num_defs += NUM_SSA_OPERANDS (stmt, SSA_OP_DEF);
 285           dfa_stats_p->num_uses += NUM_SSA_OPERANDS (stmt, SSA_OP_USE);
 286           dfa_stats_p->num_vdefs += gimple_vdef (stmt) ? 1 : 0;
 287           dfa_stats_p->num_vuses += gimple_vuse (stmt) ? 1 : 0;
 288         }
 289     }
 290 }
 291
 292
 293 /*---------------------------------------------------------------------------
 294                              Miscellaneous helpers
 295 ---------------------------------------------------------------------------*/
 296
 297 /* Lookup VAR UID in the default_defs hashtable and return the associated
 298    variable.  */
 299
 300 tree
 301 ssa_default_def (struct function *fn, tree var)
 302 {
 303   struct tree_decl_minimal ind;
 304   struct tree_ssa_name in;
 305   gcc_assert (VAR_P (var)
 306               || TREE_CODE (var) == PARM_DECL
 307               || TREE_CODE (var) == RESULT_DECL);
 308
 309   /* Always NULL_TREE for rtl function dumps.  */
 310   if (!fn->gimple_df)
 311     return NULL_TREE;
 312
 313   in.var = (tree)&ind;
 314   ind.uid = DECL_UID (var);
 315   return DEFAULT_DEFS (fn)->find_with_hash ((tree)&in, DECL_UID (var));
 316 }
 317
 318 /* Insert the pair VAR's UID, DEF into the default_defs hashtable
 319    of function FN.  */
 320
 321 void
 322 set_ssa_default_def (struct function *fn, tree var, tree def)
 323 {
 324   struct tree_decl_minimal ind;
 325   struct tree_ssa_name in;
 326
 327   gcc_assert (VAR_P (var)
 328               || TREE_CODE (var) == PARM_DECL
 329               || TREE_CODE (var) == RESULT_DECL);
 330   in.var = (tree)&ind;
 331   ind.uid = DECL_UID (var);
 332   if (!def)
 333     {
 334       tree *loc = DEFAULT_DEFS (fn)->find_slot_with_hash ((tree)&in,
 335                                                           DECL_UID (var),
 336                                                           NO_INSERT);
 337       if (loc)
 338         {
 339           SSA_NAME_IS_DEFAULT_DEF (*(tree *)loc) = false;
 340           DEFAULT_DEFS (fn)->clear_slot (loc);
 341         }
 342       return;
 343     }
 344   gcc_assert (TREE_CODE (def) == SSA_NAME && SSA_NAME_VAR (def) == var);
 345   tree *loc = DEFAULT_DEFS (fn)->find_slot_with_hash ((tree)&in,
 346                                                       DECL_UID (var), INSERT);
 347
 348   /* Default definition might be changed by tail call optimization.  */
 349   if (*loc)
 350     SSA_NAME_IS_DEFAULT_DEF (*loc) = false;
 351
 352    /* Mark DEF as the default definition for VAR.  */
 353   *loc = def;
 354   SSA_NAME_IS_DEFAULT_DEF (def) = true;
 355 }
 356
 357 /* Retrieve or create a default definition for VAR.  */
 358
 359 tree
 360 get_or_create_ssa_default_def (struct function *fn, tree var)
 361 {
 362   tree ddef = ssa_default_def (fn, var);
 363   if (ddef == NULL_TREE)
 364     {
 365       ddef = make_ssa_name_fn (fn, var, gimple_build_nop ());
 366       set_ssa_default_def (fn, var, ddef);
 367     }
 368   return ddef;
 369 }
 370
 371
 372 /* If EXP is a handled component reference for a structure, return the
 373    base variable.  The access range is delimited by bit positions *POFFSET and
 374    *POFFSET + *PMAX_SIZE.  The access size is *PSIZE bits.  If either
 375    *PSIZE or *PMAX_SIZE is -1, they could not be determined.  If *PSIZE
 376    and *PMAX_SIZE are equal, the access is non-variable.  If *PREVERSE is
 377    true, the storage order of the reference is reversed.  */
 378
 379 tree
 380 get_ref_base_and_extent (tree exp, poly_int64_pod *poffset,
 381                          poly_int64_pod *psize,
 382                          poly_int64_pod *pmax_size,
 383                          bool *preverse)
 384 {
 385   poly_offset_int bitsize = -1;
 386   poly_offset_int maxsize;
 387   tree size_tree = NULL_TREE;
 388   poly_offset_int bit_offset = 0;
 389   bool seen_variable_array_ref = false;
 390
 391   /* First get the final access size and the storage order from just the
 392      outermost expression.  */
 393   if (TREE_CODE (exp) == COMPONENT_REF)
 394     size_tree = DECL_SIZE (TREE_OPERAND (exp, 1));
 395   else if (TREE_CODE (exp) == BIT_FIELD_REF)
 396     size_tree = TREE_OPERAND (exp, 1);
 397   else if (!VOID_TYPE_P (TREE_TYPE (exp)))
 398     {
 399       machine_mode mode = TYPE_MODE (TREE_TYPE (exp));
 400       if (mode == BLKmode)
 401         size_tree = TYPE_SIZE (TREE_TYPE (exp));
 402       else
 403         bitsize = GET_MODE_BITSIZE (mode);
 404     }
 405   if (size_tree != NULL_TREE
 406       && poly_int_tree_p (size_tree))
 407     bitsize = wi::to_poly_offset (size_tree);
 408
 409   *preverse = reverse_storage_order_for_component_p (exp);
 410
 411   /* Initially, maxsize is the same as the accessed element size.
 412      In the following it will only grow (or become -1).  */
 413   maxsize = bitsize;
 414
 415   /* Compute cumulative bit-offset for nested component-refs and array-refs,
 416      and find the ultimate containing object.  */
 417   while (1)
 418     {
 419       switch (TREE_CODE (exp))
 420         {
 421         case BIT_FIELD_REF:
 422           bit_offset += wi::to_poly_offset (TREE_OPERAND (exp, 2));
 423           break;
 424
 425         case COMPONENT_REF:
 426           {
 427             tree field = TREE_OPERAND (exp, 1);
 428             tree this_offset = component_ref_field_offset (exp);
 429
 430             if (this_offset && poly_int_tree_p (this_offset))
 431               {
 432                 poly_offset_int woffset = (wi::to_poly_offset (this_offset)
 433                                            << LOG2_BITS_PER_UNIT);
 434                 woffset += wi::to_offset (DECL_FIELD_BIT_OFFSET (field));
 435                 bit_offset += woffset;
 436
 437                 /* If we had seen a variable array ref already and we just
 438                    referenced the last field of a struct or a union member
 439                    then we have to adjust maxsize by the padding at the end
 440                    of our field.  */
 441                 if (seen_variable_array_ref && known_size_p (maxsize))
 442                   {
 443                     tree stype = TREE_TYPE (TREE_OPERAND (exp, 0));
 444                     tree next = DECL_CHAIN (field);
 445                     while (next && TREE_CODE (next) != FIELD_DECL)
 446                       next = DECL_CHAIN (next);
 447                     if (!next
 448                         || TREE_CODE (stype) != RECORD_TYPE)
 449                       {
 450                         tree fsize = DECL_SIZE_UNIT (field);
 451                         tree ssize = TYPE_SIZE_UNIT (stype);
 452                         if (fsize == NULL
 453                             || !poly_int_tree_p (fsize)
 454                             || ssize == NULL
 455                             || !poly_int_tree_p (ssize))
 456                           maxsize = -1;
 457                         else
 458                           {
 459                             poly_offset_int tem
 460                               = (wi::to_poly_offset (ssize)
 461                                  - wi::to_poly_offset (fsize));
 462                             tem <<= LOG2_BITS_PER_UNIT;
 463                             tem -= woffset;
 464                             maxsize += tem;
 465                           }
 466                       }
 467                   }
 468               }
 469             else
 470               {
 471                 tree csize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 472                 /* We need to adjust maxsize to the whole structure bitsize.
 473                    But we can subtract any constant offset seen so far,
 474                    because that would get us out of the structure otherwise.  */
 475                 if (known_size_p (maxsize)
 476                     && csize
 477                     && poly_int_tree_p (csize))
 478                   maxsize = wi::to_poly_offset (csize) - bit_offset;
 479                 else
 480                   maxsize = -1;
 481               }
 482           }
 483           break;
 484
 485         case ARRAY_REF:
 486         case ARRAY_RANGE_REF:
 487           {
 488             tree index = TREE_OPERAND (exp, 1);
 489             tree low_bound, unit_size;
 490
 491             /* If the resulting bit-offset is constant, track it.  */
 492             if (poly_int_tree_p (index)
 493                 && (low_bound = array_ref_low_bound (exp),
 494                     poly_int_tree_p (low_bound))
 495                 && (unit_size = array_ref_element_size (exp),
 496                     TREE_CODE (unit_size) == INTEGER_CST))
 497               {
 498                 poly_offset_int woffset
 499                   = wi::sext (wi::to_poly_offset (index)
 500                               - wi::to_poly_offset (low_bound),
 501                               TYPE_PRECISION (TREE_TYPE (index)));
 502                 woffset *= wi::to_offset (unit_size);
 503                 woffset <<= LOG2_BITS_PER_UNIT;
 504                 bit_offset += woffset;
 505
 506                 /* An array ref with a constant index up in the structure
 507                    hierarchy will constrain the size of any variable array ref
 508                    lower in the access hierarchy.  */
 509                 seen_variable_array_ref = false;
 510               }
 511             else
 512               {
 513                 tree asize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 514                 /* We need to adjust maxsize to the whole array bitsize.
 515                    But we can subtract any constant offset seen so far,
 516                    because that would get us outside of the array otherwise.  */
 517                 if (known_size_p (maxsize)
 518                     && asize
 519                     && poly_int_tree_p (asize))
 520                   maxsize = wi::to_poly_offset (asize) - bit_offset;
 521                 else
 522                   maxsize = -1;
 523
 524                 /* Remember that we have seen an array ref with a variable
 525                    index.  */
 526                 seen_variable_array_ref = true;
 527               }
 528           }
 529           break;
 530
 531         case REALPART_EXPR:
 532           break;
 533
 534         case IMAGPART_EXPR:
 535           bit_offset += bitsize;
 536           break;
 537
 538         case VIEW_CONVERT_EXPR:
 539           break;
 540
 541         case TARGET_MEM_REF:
 542           /* Via the variable index or index2 we can reach the
 543              whole object.  Still hand back the decl here.  */
 544           if (TREE_CODE (TMR_BASE (exp)) == ADDR_EXPR
 545               && (TMR_INDEX (exp) || TMR_INDEX2 (exp)))
 546             {
 547               exp = TREE_OPERAND (TMR_BASE (exp), 0);
 548               bit_offset = 0;
 549               maxsize = -1;
 550               goto done;
 551             }
 552           /* Fallthru.  */
 553         case MEM_REF:
 554           /* We need to deal with variable arrays ending structures such as
 555              struct { int length; int a[1]; } x;           x.a[d]
 556              struct { struct { int a; int b; } a[1]; } x;  x.a[d].a
 557              struct { struct { int a[1]; } a[1]; } x;      x.a[0][d], x.a[d][0]
 558              struct { int len; union { int a[1]; struct X x; } u; } x; x.u.a[d]
 559              where we do not know maxsize for variable index accesses to
 560              the array.  The simplest way to conservatively deal with this
 561              is to punt in the case that offset + maxsize reaches the
 562              base type boundary.  This needs to include possible trailing
 563              padding that is there for alignment purposes.  */
 564           if (seen_variable_array_ref
 565               && known_size_p (maxsize)
 566               && (TYPE_SIZE (TREE_TYPE (exp)) == NULL_TREE
 567                   || !poly_int_tree_p (TYPE_SIZE (TREE_TYPE (exp)))
 568                   || (maybe_eq
 569                       (bit_offset + maxsize,
 570                        wi::to_poly_offset (TYPE_SIZE (TREE_TYPE (exp)))))))
 571             maxsize = -1;
 572
 573           /* Hand back the decl for MEM[&decl, off].  */
 574           if (TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR)
 575             {
 576               if (integer_zerop (TREE_OPERAND (exp, 1)))
 577                 exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
 578               else
 579                 {
 580                   poly_offset_int off = mem_ref_offset (exp);
 581                   off <<= LOG2_BITS_PER_UNIT;
 582                   off += bit_offset;
 583                   poly_int64 off_hwi;
 584                   if (off.to_shwi (&off_hwi))
 585                     {
 586                       bit_offset = off_hwi;
 587                       exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
 588                     }
 589                 }
 590             }
 591           goto done;
 592
 593         default:
 594           goto done;
 595         }
 596
 597       exp = TREE_OPERAND (exp, 0);
 598     }
 599
 600  done:
 601   if (!bitsize.to_shwi (psize) || maybe_lt (*psize, 0))
 602     {
 603       *poffset = 0;
 604       *psize = -1;
 605       *pmax_size = -1;
 606
 607       return exp;
 608     }
 609
 610   /* ???  Due to negative offsets in ARRAY_REF we can end up with
 611      negative bit_offset here.  We might want to store a zero offset
 612      in this case.  */
 613   if (!bit_offset.to_shwi (poffset))
 614     {
 615       *poffset = 0;
 616       *pmax_size = -1;
 617
 618       return exp;
 619     }
 620
 621   /* In case of a decl or constant base object we can do better.  */
 622
 623   if (DECL_P (exp))
 624     {
 625       if (flag_unconstrained_commons && VAR_P (exp) && DECL_COMMON (exp))
 626         {
 627           tree sz_tree = TYPE_SIZE (TREE_TYPE (exp));
 628           /* If size is unknown, or we have read to the end, assume there
 629              may be more to the structure than we are told.  */
 630           if (TREE_CODE (TREE_TYPE (exp)) == ARRAY_TYPE
 631               || (seen_variable_array_ref
 632                   && (sz_tree == NULL_TREE
 633                       || !poly_int_tree_p (sz_tree)
 634                       || maybe_eq (bit_offset + maxsize,
 635                                    wi::to_poly_offset (sz_tree)))))
 636             maxsize = -1;
 637         }
 638       /* If maxsize is unknown adjust it according to the size of the
 639          base decl.  */
 640       else if (!known_size_p (maxsize)
 641                && DECL_SIZE (exp)
 642                && poly_int_tree_p (DECL_SIZE (exp)))
 643         maxsize = wi::to_poly_offset (DECL_SIZE (exp)) - bit_offset;
 644     }
 645   else if (CONSTANT_CLASS_P (exp))
 646     {
 647       /* If maxsize is unknown adjust it according to the size of the
 648          base type constant.  */
 649       if (!known_size_p (maxsize)
 650           && TYPE_SIZE (TREE_TYPE (exp))
 651           && poly_int_tree_p (TYPE_SIZE (TREE_TYPE (exp))))
 652         maxsize = (wi::to_poly_offset (TYPE_SIZE (TREE_TYPE (exp)))
 653                    - bit_offset);
 654     }
 655
 656   if (!maxsize.to_shwi (pmax_size)
 657       || maybe_lt (*pmax_size, 0)
 658       || !endpoint_representable_p (*poffset, *pmax_size))
 659     *pmax_size = -1;
 660
 661   /* Punt if *POFFSET + *PSIZE overflows in HOST_WIDE_INT, the callers don't
 662      check for such overflows individually and assume it works.  */
 663   if (!endpoint_representable_p (*poffset, *psize))
 664     {
 665       *poffset = 0;
 666       *psize = -1;
 667       *pmax_size = -1;
 668
 669       return exp;
 670     }
 671
 672   return exp;
 673 }
 674
 675 /* Like get_ref_base_and_extent, but for cases in which we only care
 676    about constant-width accesses at constant offsets.  Return null
 677    if the access is anything else.  */
 678
 679 tree
 680 get_ref_base_and_extent_hwi (tree exp, HOST_WIDE_INT *poffset,
 681                              HOST_WIDE_INT *psize, bool *preverse)
 682 {
 683   poly_int64 offset, size, max_size;
 684   HOST_WIDE_INT const_offset, const_size;
 685   bool reverse;
 686   tree decl = get_ref_base_and_extent (exp, &offset, &size, &max_size,
 687                                        &reverse);
 688   if (!offset.is_constant (&const_offset)
 689       || !size.is_constant (&const_size)
 690       || const_offset < 0
 691       || !known_size_p (max_size)
 692       || maybe_ne (max_size, const_size))
 693     return NULL_TREE;
 694
 695   *poffset = const_offset;
 696   *psize = const_size;
 697   *preverse = reverse;
 698   return decl;
 699 }
 700
 701 /* Returns the base object and a constant BITS_PER_UNIT offset in *POFFSET that
 702    denotes the starting address of the memory access EXP.
 703    Returns NULL_TREE if the offset is not constant or any component
 704    is not BITS_PER_UNIT-aligned.
 705    VALUEIZE if non-NULL is used to valueize SSA names.  It should return
 706    its argument or a constant if the argument is known to be constant.  */
 707
 708 tree
 709 get_addr_base_and_unit_offset_1 (tree exp, poly_int64_pod *poffset,
 710                                  tree (*valueize) (tree))
 711 {
 712   poly_int64 byte_offset = 0;
 713
 714   /* Compute cumulative byte-offset for nested component-refs and array-refs,
 715      and find the ultimate containing object.  */
 716   while (1)
 717     {
 718       switch (TREE_CODE (exp))
 719         {
 720         case BIT_FIELD_REF:
 721           {
 722             poly_int64 this_byte_offset;
 723             poly_uint64 this_bit_offset;
 724             if (!poly_int_tree_p (TREE_OPERAND (exp, 2), &this_bit_offset)
 725                 || !multiple_p (this_bit_offset, BITS_PER_UNIT,
 726                                 &this_byte_offset))
 727               return NULL_TREE;
 728             byte_offset += this_byte_offset;
 729           }
 730           break;
 731
 732         case COMPONENT_REF:
 733           {
 734             tree field = TREE_OPERAND (exp, 1);
 735             tree this_offset = component_ref_field_offset (exp);
 736             poly_int64 hthis_offset;
 737
 738             if (!this_offset
 739                 || !poly_int_tree_p (this_offset, &hthis_offset)
 740                 || (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
 741                     % BITS_PER_UNIT))
 742               return NULL_TREE;
 743
 744             hthis_offset += (TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field))
 745                              / BITS_PER_UNIT);
 746             byte_offset += hthis_offset;
 747           }
 748           break;
 749
 750         case ARRAY_REF:
 751         case ARRAY_RANGE_REF:
 752           {
 753             tree index = TREE_OPERAND (exp, 1);
 754             tree low_bound, unit_size;
 755
 756             if (valueize
 757                 && TREE_CODE (index) == SSA_NAME)
 758               index = (*valueize) (index);
 759
 760             /* If the resulting bit-offset is constant, track it.  */
 761             if (poly_int_tree_p (index)
 762                 && (low_bound = array_ref_low_bound (exp),
 763                     poly_int_tree_p (low_bound))
 764                 && (unit_size = array_ref_element_size (exp),
 765                     TREE_CODE (unit_size) == INTEGER_CST))
 766               {
 767                 poly_offset_int woffset
 768                   = wi::sext (wi::to_poly_offset (index)
 769                               - wi::to_poly_offset (low_bound),
 770                               TYPE_PRECISION (TREE_TYPE (index)));
 771                 woffset *= wi::to_offset (unit_size);
 772                 byte_offset += woffset.force_shwi ();
 773               }
 774             else
 775               return NULL_TREE;
 776           }
 777           break;
 778
 779         case REALPART_EXPR:
 780           break;
 781
 782         case IMAGPART_EXPR:
 783           byte_offset += TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (exp)));
 784           break;
 785
 786         case VIEW_CONVERT_EXPR:
 787           break;
 788
 789         case MEM_REF:
 790           {
 791             tree base = TREE_OPERAND (exp, 0);
 792             if (valueize
 793                 && TREE_CODE (base) == SSA_NAME)
 794               base = (*valueize) (base);
 795
 796             /* Hand back the decl for MEM[&decl, off].  */
 797             if (TREE_CODE (base) == ADDR_EXPR)
 798               {
 799                 if (!integer_zerop (TREE_OPERAND (exp, 1)))
 800                   {
 801                     poly_offset_int off = mem_ref_offset (exp);
 802                     byte_offset += off.force_shwi ();
 803                   }
 804                 exp = TREE_OPERAND (base, 0);
 805               }
 806             goto done;
 807           }
 808
 809         case TARGET_MEM_REF:
 810           {
 811             tree base = TREE_OPERAND (exp, 0);
 812             if (valueize
 813                 && TREE_CODE (base) == SSA_NAME)
 814               base = (*valueize) (base);
 815
 816             /* Hand back the decl for MEM[&decl, off].  */
 817             if (TREE_CODE (base) == ADDR_EXPR)
 818               {
 819                 if (TMR_INDEX (exp) || TMR_INDEX2 (exp))
 820                   return NULL_TREE;
 821                 if (!integer_zerop (TMR_OFFSET (exp)))
 822                   {
 823                     poly_offset_int off = mem_ref_offset (exp);
 824                     byte_offset += off.force_shwi ();
 825                   }
 826                 exp = TREE_OPERAND (base, 0);
 827               }
 828             goto done;
 829           }
 830
 831         default:
 832           goto done;
 833         }
 834
 835       exp = TREE_OPERAND (exp, 0);
 836     }
 837 done:
 838
 839   *poffset = byte_offset;
 840   return exp;
 841 }
 842
 843 /* Returns the base object and a constant BITS_PER_UNIT offset in *POFFSET that
 844    denotes the starting address of the memory access EXP.
 845    Returns NULL_TREE if the offset is not constant or any component
 846    is not BITS_PER_UNIT-aligned.  */
 847
 848 tree
 849 get_addr_base_and_unit_offset (tree exp, poly_int64_pod *poffset)
 850 {
 851   return get_addr_base_and_unit_offset_1 (exp, poffset, NULL);
 852 }
 853
 854 /* Returns true if STMT references an SSA_NAME that has
 855    SSA_NAME_OCCURS_IN_ABNORMAL_PHI set, otherwise false.  */
 856
 857 bool
 858 stmt_references_abnormal_ssa_name (gimple *stmt)
 859 {
 860   ssa_op_iter oi;
 861   use_operand_p use_p;
 862
 863   FOR_EACH_SSA_USE_OPERAND (use_p, stmt, oi, SSA_OP_USE)
 864     {
 865       if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (use_p)))
 866         return true;
 867     }
 868
 869   return false;
 870 }
 871
 872 /* If STMT takes any abnormal PHI values as input, replace them with
 873    local copies.  */
 874
 875 void
 876 replace_abnormal_ssa_names (gimple *stmt)
 877 {
 878   ssa_op_iter oi;
 879   use_operand_p use_p;
 880
 881   FOR_EACH_SSA_USE_OPERAND (use_p, stmt, oi, SSA_OP_USE)
 882     {
 883       tree op = USE_FROM_PTR (use_p);
 884       if (TREE_CODE (op) == SSA_NAME && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
 885         {
 886           gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
 887           tree new_name = make_ssa_name (TREE_TYPE (op));
 888           gassign *assign = gimple_build_assign (new_name, op);
 889           gsi_insert_before (&gsi, assign, GSI_SAME_STMT);
 890           SET_USE (use_p, new_name);
 891         }
 892     }
 893 }
 894
 895 /* Pair of tree and a sorting index, for dump_enumerated_decls.  */
 896 struct GTY(()) numbered_tree
 897 {
 898   tree t;
 899   int num;
 900 };
 901
 902
 903 /* Compare two declarations references by their DECL_UID / sequence number.
 904    Called via qsort.  */
 905
 906 static int
 907 compare_decls_by_uid (const void *pa, const void *pb)
 908 {
 909   const numbered_tree *nt_a = ((const numbered_tree *)pa);
 910   const numbered_tree *nt_b = ((const numbered_tree *)pb);
 911
 912   if (DECL_UID (nt_a->t) != DECL_UID (nt_b->t))
 913     return  DECL_UID (nt_a->t) - DECL_UID (nt_b->t);
 914   return nt_a->num - nt_b->num;
 915 }
 916
 917 /* Called via walk_gimple_stmt / walk_gimple_op by dump_enumerated_decls.  */
 918 static tree
 919 dump_enumerated_decls_push (tree *tp, int *walk_subtrees, void *data)
 920 {
 921   struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
 922   vec<numbered_tree> *list = (vec<numbered_tree> *) wi->info;
 923   numbered_tree nt;
 924
 925   if (!DECL_P (*tp))
 926     return NULL_TREE;
 927   nt.t = *tp;
 928   nt.num = list->length ();
 929   list->safe_push (nt);
 930   *walk_subtrees = 0;
 931   return NULL_TREE;
 932 }
 933
 934 /* Find all the declarations used by the current function, sort them by uid,
 935    and emit the sorted list.  Each declaration is tagged with a sequence
 936    number indicating when it was found during statement / tree walking,
 937    so that TDF_NOUID comparisons of anonymous declarations are still
 938    meaningful.  Where a declaration was encountered more than once, we
 939    emit only the sequence number of the first encounter.
 940    FILE is the dump file where to output the list and FLAGS is as in
 941    print_generic_expr.  */
 942 void
 943 dump_enumerated_decls (FILE *file, dump_flags_t flags)
 944 {
 945   basic_block bb;
 946   struct walk_stmt_info wi;
 947   auto_vec<numbered_tree, 40> decl_list;
 948
 949   memset (&wi, '\0', sizeof (wi));
 950   wi.info = (void *) &decl_list;
 951   FOR_EACH_BB_FN (bb, cfun)
 952     {
 953       gimple_stmt_iterator gsi;
 954
 955       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 956         if (!is_gimple_debug (gsi_stmt (gsi)))
 957           walk_gimple_stmt (&gsi, NULL, dump_enumerated_decls_push, &wi);
 958     }
 959   decl_list.qsort (compare_decls_by_uid);
 960   if (decl_list.length ())
 961     {
 962       unsigned ix;
 963       numbered_tree *ntp;
 964       tree last = NULL_TREE;
 965
 966       fprintf (file, "Declarations used by %s, sorted by DECL_UID:\n",
 967                current_function_name ());
 968       FOR_EACH_VEC_ELT (decl_list, ix, ntp)
 969         {
 970           if (ntp->t == last)
 971             continue;
 972           fprintf (file, "%d: ", ntp->num);
 973           print_generic_decl (file, ntp->t, flags);
 974           fprintf (file, "\n");
 975           last = ntp->t;
 976         }
 977     }
 978 }