gcc/cp/cp-gimplify.c

   1 /* C++-specific tree lowering bits; see also c-gimplify.c and tree-gimple.c.
   2
   3    Copyright (C) 2002-2018 Free Software Foundation, Inc.
   4    Contributed by Jason Merrill <jason@redhat.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "target.h"
  26 #include "basic-block.h"
  27 #include "cp-tree.h"
  28 #include "gimple.h"
  29 #include "predict.h"
  30 #include "stor-layout.h"
  31 #include "tree-iterator.h"
  32 #include "gimplify.h"
  33 #include "c-family/c-ubsan.h"
  34 #include "stringpool.h"
  35 #include "attribs.h"
  36 #include "asan.h"
  37
  38 /* Forward declarations.  */
  39
  40 static tree cp_genericize_r (tree *, int *, void *);
  41 static tree cp_fold_r (tree *, int *, void *);
  42 static void cp_genericize_tree (tree*, bool);
  43 static tree cp_fold (tree);
  44
  45 /* Local declarations.  */
  46
  47 enum bc_t { bc_break = 0, bc_continue = 1 };
  48
  49 /* Stack of labels which are targets for "break" or "continue",
  50    linked through TREE_CHAIN.  */
  51 static tree bc_label[2];
  52
  53 /* Begin a scope which can be exited by a break or continue statement.  BC
  54    indicates which.
  55
  56    Just creates a label with location LOCATION and pushes it into the current
  57    context.  */
  58
  59 static tree
  60 begin_bc_block (enum bc_t bc, location_t location)
  61 {
  62   tree label = create_artificial_label (location);
  63   DECL_CHAIN (label) = bc_label[bc];
  64   bc_label[bc] = label;
  65   if (bc == bc_break)
  66     LABEL_DECL_BREAK (label) = true;
  67   else
  68     LABEL_DECL_CONTINUE (label) = true;
  69   return label;
  70 }
  71
  72 /* Finish a scope which can be exited by a break or continue statement.
  73    LABEL was returned from the most recent call to begin_bc_block.  BLOCK is
  74    an expression for the contents of the scope.
  75
  76    If we saw a break (or continue) in the scope, append a LABEL_EXPR to
  77    BLOCK.  Otherwise, just forget the label.  */
  78
  79 static void
  80 finish_bc_block (tree *block, enum bc_t bc, tree label)
  81 {
  82   gcc_assert (label == bc_label[bc]);
  83
  84   if (TREE_USED (label))
  85     append_to_statement_list (build1 (LABEL_EXPR, void_type_node, label),
  86                               block);
  87
  88   bc_label[bc] = DECL_CHAIN (label);
  89   DECL_CHAIN (label) = NULL_TREE;
  90 }
  91
  92 /* Get the LABEL_EXPR to represent a break or continue statement
  93    in the current block scope.  BC indicates which.  */
  94
  95 static tree
  96 get_bc_label (enum bc_t bc)
  97 {
  98   tree label = bc_label[bc];
  99
 100   /* Mark the label used for finish_bc_block.  */
 101   TREE_USED (label) = 1;
 102   return label;
 103 }
 104
 105 /* Genericize a TRY_BLOCK.  */
 106
 107 static void
 108 genericize_try_block (tree *stmt_p)
 109 {
 110   tree body = TRY_STMTS (*stmt_p);
 111   tree cleanup = TRY_HANDLERS (*stmt_p);
 112
 113   *stmt_p = build2 (TRY_CATCH_EXPR, void_type_node, body, cleanup);
 114 }
 115
 116 /* Genericize a HANDLER by converting to a CATCH_EXPR.  */
 117
 118 static void
 119 genericize_catch_block (tree *stmt_p)
 120 {
 121   tree type = HANDLER_TYPE (*stmt_p);
 122   tree body = HANDLER_BODY (*stmt_p);
 123
 124   /* FIXME should the caught type go in TREE_TYPE?  */
 125   *stmt_p = build2 (CATCH_EXPR, void_type_node, type, body);
 126 }
 127
 128 /* A terser interface for building a representation of an exception
 129    specification.  */
 130
 131 static tree
 132 build_gimple_eh_filter_tree (tree body, tree allowed, tree failure)
 133 {
 134   tree t;
 135
 136   /* FIXME should the allowed types go in TREE_TYPE?  */
 137   t = build2 (EH_FILTER_EXPR, void_type_node, allowed, NULL_TREE);
 138   append_to_statement_list (failure, &EH_FILTER_FAILURE (t));
 139
 140   t = build2 (TRY_CATCH_EXPR, void_type_node, NULL_TREE, t);
 141   append_to_statement_list (body, &TREE_OPERAND (t, 0));
 142
 143   return t;
 144 }
 145
 146 /* Genericize an EH_SPEC_BLOCK by converting it to a
 147    TRY_CATCH_EXPR/EH_FILTER_EXPR pair.  */
 148
 149 static void
 150 genericize_eh_spec_block (tree *stmt_p)
 151 {
 152   tree body = EH_SPEC_STMTS (*stmt_p);
 153   tree allowed = EH_SPEC_RAISES (*stmt_p);
 154   tree failure = build_call_n (call_unexpected_fn, 1, build_exc_ptr ());
 155
 156   *stmt_p = build_gimple_eh_filter_tree (body, allowed, failure);
 157   TREE_NO_WARNING (*stmt_p) = true;
 158   TREE_NO_WARNING (TREE_OPERAND (*stmt_p, 1)) = true;
 159 }
 160
 161 /* Genericize an IF_STMT by turning it into a COND_EXPR.  */
 162
 163 static void
 164 genericize_if_stmt (tree *stmt_p)
 165 {
 166   tree stmt, cond, then_, else_;
 167   location_t locus = EXPR_LOCATION (*stmt_p);
 168
 169   stmt = *stmt_p;
 170   cond = IF_COND (stmt);
 171   then_ = THEN_CLAUSE (stmt);
 172   else_ = ELSE_CLAUSE (stmt);
 173
 174   if (!then_)
 175     then_ = build_empty_stmt (locus);
 176   if (!else_)
 177     else_ = build_empty_stmt (locus);
 178
 179   if (integer_nonzerop (cond) && !TREE_SIDE_EFFECTS (else_))
 180     stmt = then_;
 181   else if (integer_zerop (cond) && !TREE_SIDE_EFFECTS (then_))
 182     stmt = else_;
 183   else
 184     stmt = build3 (COND_EXPR, void_type_node, cond, then_, else_);
 185   if (!EXPR_HAS_LOCATION (stmt))
 186     protected_set_expr_location (stmt, locus);
 187   *stmt_p = stmt;
 188 }
 189
 190 /* Build a generic representation of one of the C loop forms.  COND is the
 191    loop condition or NULL_TREE.  BODY is the (possibly compound) statement
 192    controlled by the loop.  INCR is the increment expression of a for-loop,
 193    or NULL_TREE.  COND_IS_FIRST indicates whether the condition is
 194    evaluated before the loop body as in while and for loops, or after the
 195    loop body as in do-while loops.  */
 196
 197 static void
 198 genericize_cp_loop (tree *stmt_p, location_t start_locus, tree cond, tree body,
 199                     tree incr, bool cond_is_first, int *walk_subtrees,
 200                     void *data)
 201 {
 202   tree blab, clab;
 203   tree exit = NULL;
 204   tree stmt_list = NULL;
 205
 206   blab = begin_bc_block (bc_break, start_locus);
 207   clab = begin_bc_block (bc_continue, start_locus);
 208
 209   protected_set_expr_location (incr, start_locus);
 210
 211   cp_walk_tree (&cond, cp_genericize_r, data, NULL);
 212   cp_walk_tree (&body, cp_genericize_r, data, NULL);
 213   cp_walk_tree (&incr, cp_genericize_r, data, NULL);
 214   *walk_subtrees = 0;
 215
 216   if (cond && TREE_CODE (cond) != INTEGER_CST)
 217     {
 218       /* If COND is constant, don't bother building an exit.  If it's false,
 219          we won't build a loop.  If it's true, any exits are in the body.  */
 220       location_t cloc = cp_expr_loc_or_loc (cond, start_locus);
 221       exit = build1_loc (cloc, GOTO_EXPR, void_type_node,
 222                          get_bc_label (bc_break));
 223       exit = fold_build3_loc (cloc, COND_EXPR, void_type_node, cond,
 224                               build_empty_stmt (cloc), exit);
 225     }
 226
 227   if (exit && cond_is_first)
 228     append_to_statement_list (exit, &stmt_list);
 229   append_to_statement_list (body, &stmt_list);
 230   finish_bc_block (&stmt_list, bc_continue, clab);
 231   append_to_statement_list (incr, &stmt_list);
 232   if (exit && !cond_is_first)
 233     append_to_statement_list (exit, &stmt_list);
 234
 235   if (!stmt_list)
 236     stmt_list = build_empty_stmt (start_locus);
 237
 238   tree loop;
 239   if (cond && integer_zerop (cond))
 240     {
 241       if (cond_is_first)
 242         loop = fold_build3_loc (start_locus, COND_EXPR,
 243                                 void_type_node, cond, stmt_list,
 244                                 build_empty_stmt (start_locus));
 245       else
 246         loop = stmt_list;
 247     }
 248   else
 249     {
 250       location_t loc = start_locus;
 251       if (!cond || integer_nonzerop (cond))
 252         loc = EXPR_LOCATION (expr_first (body));
 253       if (loc == UNKNOWN_LOCATION)
 254         loc = start_locus;
 255       loop = build1_loc (loc, LOOP_EXPR, void_type_node, stmt_list);
 256     }
 257
 258   stmt_list = NULL;
 259   append_to_statement_list (loop, &stmt_list);
 260   finish_bc_block (&stmt_list, bc_break, blab);
 261   if (!stmt_list)
 262     stmt_list = build_empty_stmt (start_locus);
 263
 264   *stmt_p = stmt_list;
 265 }
 266
 267 /* Genericize a FOR_STMT node *STMT_P.  */
 268
 269 static void
 270 genericize_for_stmt (tree *stmt_p, int *walk_subtrees, void *data)
 271 {
 272   tree stmt = *stmt_p;
 273   tree expr = NULL;
 274   tree loop;
 275   tree init = FOR_INIT_STMT (stmt);
 276
 277   if (init)
 278     {
 279       cp_walk_tree (&init, cp_genericize_r, data, NULL);
 280       append_to_statement_list (init, &expr);
 281     }
 282
 283   genericize_cp_loop (&loop, EXPR_LOCATION (stmt), FOR_COND (stmt),
 284                       FOR_BODY (stmt), FOR_EXPR (stmt), 1, walk_subtrees, data);
 285   append_to_statement_list (loop, &expr);
 286   if (expr == NULL_TREE)
 287     expr = loop;
 288   *stmt_p = expr;
 289 }
 290
 291 /* Genericize a WHILE_STMT node *STMT_P.  */
 292
 293 static void
 294 genericize_while_stmt (tree *stmt_p, int *walk_subtrees, void *data)
 295 {
 296   tree stmt = *stmt_p;
 297   genericize_cp_loop (stmt_p, EXPR_LOCATION (stmt), WHILE_COND (stmt),
 298                       WHILE_BODY (stmt), NULL_TREE, 1, walk_subtrees, data);
 299 }
 300
 301 /* Genericize a DO_STMT node *STMT_P.  */
 302
 303 static void
 304 genericize_do_stmt (tree *stmt_p, int *walk_subtrees, void *data)
 305 {
 306   tree stmt = *stmt_p;
 307   genericize_cp_loop (stmt_p, EXPR_LOCATION (stmt), DO_COND (stmt),
 308                       DO_BODY (stmt), NULL_TREE, 0, walk_subtrees, data);
 309 }
 310
 311 /* Genericize a SWITCH_STMT node *STMT_P by turning it into a SWITCH_EXPR.  */
 312
 313 static void
 314 genericize_switch_stmt (tree *stmt_p, int *walk_subtrees, void *data)
 315 {
 316   tree stmt = *stmt_p;
 317   tree break_block, body, cond, type;
 318   location_t stmt_locus = EXPR_LOCATION (stmt);
 319
 320   break_block = begin_bc_block (bc_break, stmt_locus);
 321
 322   body = SWITCH_STMT_BODY (stmt);
 323   if (!body)
 324     body = build_empty_stmt (stmt_locus);
 325   cond = SWITCH_STMT_COND (stmt);
 326   type = SWITCH_STMT_TYPE (stmt);
 327
 328   cp_walk_tree (&body, cp_genericize_r, data, NULL);
 329   cp_walk_tree (&cond, cp_genericize_r, data, NULL);
 330   cp_walk_tree (&type, cp_genericize_r, data, NULL);
 331   *walk_subtrees = 0;
 332
 333   if (TREE_USED (break_block))
 334     SWITCH_BREAK_LABEL_P (break_block) = 1;
 335   finish_bc_block (&body, bc_break, break_block);
 336   *stmt_p = build2_loc (stmt_locus, SWITCH_EXPR, type, cond, body);
 337   SWITCH_ALL_CASES_P (*stmt_p) = SWITCH_STMT_ALL_CASES_P (stmt);
 338   gcc_checking_assert (!SWITCH_STMT_NO_BREAK_P (stmt)
 339                        || !TREE_USED (break_block));
 340 }
 341
 342 /* Genericize a CONTINUE_STMT node *STMT_P.  */
 343
 344 static void
 345 genericize_continue_stmt (tree *stmt_p)
 346 {
 347   tree stmt_list = NULL;
 348   tree pred = build_predict_expr (PRED_CONTINUE, NOT_TAKEN);
 349   tree label = get_bc_label (bc_continue);
 350   location_t location = EXPR_LOCATION (*stmt_p);
 351   tree jump = build1_loc (location, GOTO_EXPR, void_type_node, label);
 352   append_to_statement_list_force (pred, &stmt_list);
 353   append_to_statement_list (jump, &stmt_list);
 354   *stmt_p = stmt_list;
 355 }
 356
 357 /* Genericize a BREAK_STMT node *STMT_P.  */
 358
 359 static void
 360 genericize_break_stmt (tree *stmt_p)
 361 {
 362   tree label = get_bc_label (bc_break);
 363   location_t location = EXPR_LOCATION (*stmt_p);
 364   *stmt_p = build1_loc (location, GOTO_EXPR, void_type_node, label);
 365 }
 366
 367 /* Genericize a OMP_FOR node *STMT_P.  */
 368
 369 static void
 370 genericize_omp_for_stmt (tree *stmt_p, int *walk_subtrees, void *data)
 371 {
 372   tree stmt = *stmt_p;
 373   location_t locus = EXPR_LOCATION (stmt);
 374   tree clab = begin_bc_block (bc_continue, locus);
 375
 376   cp_walk_tree (&OMP_FOR_BODY (stmt), cp_genericize_r, data, NULL);
 377   if (TREE_CODE (stmt) != OMP_TASKLOOP)
 378     cp_walk_tree (&OMP_FOR_CLAUSES (stmt), cp_genericize_r, data, NULL);
 379   cp_walk_tree (&OMP_FOR_INIT (stmt), cp_genericize_r, data, NULL);
 380   cp_walk_tree (&OMP_FOR_COND (stmt), cp_genericize_r, data, NULL);
 381   cp_walk_tree (&OMP_FOR_INCR (stmt), cp_genericize_r, data, NULL);
 382   cp_walk_tree (&OMP_FOR_PRE_BODY (stmt), cp_genericize_r, data, NULL);
 383   *walk_subtrees = 0;
 384
 385   finish_bc_block (&OMP_FOR_BODY (stmt), bc_continue, clab);
 386 }
 387
 388 /* Hook into the middle of gimplifying an OMP_FOR node.  */
 389
 390 static enum gimplify_status
 391 cp_gimplify_omp_for (tree *expr_p, gimple_seq *pre_p)
 392 {
 393   tree for_stmt = *expr_p;
 394   gimple_seq seq = NULL;
 395
 396   /* Protect ourselves from recursion.  */
 397   if (OMP_FOR_GIMPLIFYING_P (for_stmt))
 398     return GS_UNHANDLED;
 399   OMP_FOR_GIMPLIFYING_P (for_stmt) = 1;
 400
 401   gimplify_and_add (for_stmt, &seq);
 402   gimple_seq_add_seq (pre_p, seq);
 403
 404   OMP_FOR_GIMPLIFYING_P (for_stmt) = 0;
 405
 406   return GS_ALL_DONE;
 407 }
 408
 409 /*  Gimplify an EXPR_STMT node.  */
 410
 411 static void
 412 gimplify_expr_stmt (tree *stmt_p)
 413 {
 414   tree stmt = EXPR_STMT_EXPR (*stmt_p);
 415
 416   if (stmt == error_mark_node)
 417     stmt = NULL;
 418
 419   /* Gimplification of a statement expression will nullify the
 420      statement if all its side effects are moved to *PRE_P and *POST_P.
 421
 422      In this case we will not want to emit the gimplified statement.
 423      However, we may still want to emit a warning, so we do that before
 424      gimplification.  */
 425   if (stmt && warn_unused_value)
 426     {
 427       if (!TREE_SIDE_EFFECTS (stmt))
 428         {
 429           if (!IS_EMPTY_STMT (stmt)
 430               && !VOID_TYPE_P (TREE_TYPE (stmt))
 431               && !TREE_NO_WARNING (stmt))
 432             warning (OPT_Wunused_value, "statement with no effect");
 433         }
 434       else
 435         warn_if_unused_value (stmt, input_location);
 436     }
 437
 438   if (stmt == NULL_TREE)
 439     stmt = alloc_stmt_list ();
 440
 441   *stmt_p = stmt;
 442 }
 443
 444 /* Gimplify initialization from an AGGR_INIT_EXPR.  */
 445
 446 static void
 447 cp_gimplify_init_expr (tree *expr_p)
 448 {
 449   tree from = TREE_OPERAND (*expr_p, 1);
 450   tree to = TREE_OPERAND (*expr_p, 0);
 451   tree t;
 452
 453   /* What about code that pulls out the temp and uses it elsewhere?  I
 454      think that such code never uses the TARGET_EXPR as an initializer.  If
 455      I'm wrong, we'll abort because the temp won't have any RTL.  In that
 456      case, I guess we'll need to replace references somehow.  */
 457   if (TREE_CODE (from) == TARGET_EXPR)
 458     from = TARGET_EXPR_INITIAL (from);
 459
 460   /* Look through any COMPOUND_EXPRs, since build_compound_expr pushes them
 461      inside the TARGET_EXPR.  */
 462   for (t = from; t; )
 463     {
 464       tree sub = TREE_CODE (t) == COMPOUND_EXPR ? TREE_OPERAND (t, 0) : t;
 465
 466       /* If we are initializing from an AGGR_INIT_EXPR, drop the INIT_EXPR and
 467          replace the slot operand with our target.
 468
 469          Should we add a target parm to gimplify_expr instead?  No, as in this
 470          case we want to replace the INIT_EXPR.  */
 471       if (TREE_CODE (sub) == AGGR_INIT_EXPR
 472           || TREE_CODE (sub) == VEC_INIT_EXPR)
 473         {
 474           if (TREE_CODE (sub) == AGGR_INIT_EXPR)
 475             AGGR_INIT_EXPR_SLOT (sub) = to;
 476           else
 477             VEC_INIT_EXPR_SLOT (sub) = to;
 478           *expr_p = from;
 479
 480           /* The initialization is now a side-effect, so the container can
 481              become void.  */
 482           if (from != sub)
 483             TREE_TYPE (from) = void_type_node;
 484         }
 485
 486       /* Handle aggregate NSDMI.  */
 487       replace_placeholders (sub, to);
 488
 489       if (t == sub)
 490         break;
 491       else
 492         t = TREE_OPERAND (t, 1);
 493     }
 494
 495 }
 496
 497 /* Gimplify a MUST_NOT_THROW_EXPR.  */
 498
 499 static enum gimplify_status
 500 gimplify_must_not_throw_expr (tree *expr_p, gimple_seq *pre_p)
 501 {
 502   tree stmt = *expr_p;
 503   tree temp = voidify_wrapper_expr (stmt, NULL);
 504   tree body = TREE_OPERAND (stmt, 0);
 505   gimple_seq try_ = NULL;
 506   gimple_seq catch_ = NULL;
 507   gimple *mnt;
 508
 509   gimplify_and_add (body, &try_);
 510   mnt = gimple_build_eh_must_not_throw (terminate_fn);
 511   gimple_seq_add_stmt_without_update (&catch_, mnt);
 512   mnt = gimple_build_try (try_, catch_, GIMPLE_TRY_CATCH);
 513
 514   gimple_seq_add_stmt_without_update (pre_p, mnt);
 515   if (temp)
 516     {
 517       *expr_p = temp;
 518       return GS_OK;
 519     }
 520
 521   *expr_p = NULL;
 522   return GS_ALL_DONE;
 523 }
 524
 525 /* Return TRUE if an operand (OP) of a given TYPE being copied is
 526    really just an empty class copy.
 527
 528    Check that the operand has a simple form so that TARGET_EXPRs and
 529    non-empty CONSTRUCTORs get reduced properly, and we leave the
 530    return slot optimization alone because it isn't a copy.  */
 531
 532 static bool
 533 simple_empty_class_p (tree type, tree op)
 534 {
 535   return
 536     ((TREE_CODE (op) == COMPOUND_EXPR
 537       && simple_empty_class_p (type, TREE_OPERAND (op, 1)))
 538      || TREE_CODE (op) == EMPTY_CLASS_EXPR
 539      || is_gimple_lvalue (op)
 540      || INDIRECT_REF_P (op)
 541      || (TREE_CODE (op) == CONSTRUCTOR
 542          && CONSTRUCTOR_NELTS (op) == 0
 543          && !TREE_CLOBBER_P (op))
 544      || (TREE_CODE (op) == CALL_EXPR
 545          && !CALL_EXPR_RETURN_SLOT_OPT (op)))
 546     && is_really_empty_class (type);
 547 }
 548
 549 /* Returns true if evaluating E as an lvalue has side-effects;
 550    specifically, a volatile lvalue has TREE_SIDE_EFFECTS, but it doesn't really
 551    have side-effects until there is a read or write through it.  */
 552
 553 static bool
 554 lvalue_has_side_effects (tree e)
 555 {
 556   if (!TREE_SIDE_EFFECTS (e))
 557     return false;
 558   while (handled_component_p (e))
 559     {
 560       if (TREE_CODE (e) == ARRAY_REF
 561           && TREE_SIDE_EFFECTS (TREE_OPERAND (e, 1)))
 562         return true;
 563       e = TREE_OPERAND (e, 0);
 564     }
 565   if (DECL_P (e))
 566     /* Just naming a variable has no side-effects.  */
 567     return false;
 568   else if (INDIRECT_REF_P (e))
 569     /* Similarly, indirection has no side-effects.  */
 570     return TREE_SIDE_EFFECTS (TREE_OPERAND (e, 0));
 571   else
 572     /* For anything else, trust TREE_SIDE_EFFECTS.  */
 573     return TREE_SIDE_EFFECTS (e);
 574 }
 575
 576 /* Do C++-specific gimplification.  Args are as for gimplify_expr.  */
 577
 578 int
 579 cp_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 580 {
 581   int saved_stmts_are_full_exprs_p = 0;
 582   location_t loc = cp_expr_loc_or_loc (*expr_p, input_location);
 583   enum tree_code code = TREE_CODE (*expr_p);
 584   enum gimplify_status ret;
 585
 586   if (STATEMENT_CODE_P (code))
 587     {
 588       saved_stmts_are_full_exprs_p = stmts_are_full_exprs_p ();
 589       current_stmt_tree ()->stmts_are_full_exprs_p
 590         = STMT_IS_FULL_EXPR_P (*expr_p);
 591     }
 592
 593   switch (code)
 594     {
 595     case AGGR_INIT_EXPR:
 596       simplify_aggr_init_expr (expr_p);
 597       ret = GS_OK;
 598       break;
 599
 600     case VEC_INIT_EXPR:
 601       {
 602         location_t loc = input_location;
 603         tree init = VEC_INIT_EXPR_INIT (*expr_p);
 604         int from_array = (init && TREE_CODE (TREE_TYPE (init)) == ARRAY_TYPE);
 605         gcc_assert (EXPR_HAS_LOCATION (*expr_p));
 606         input_location = EXPR_LOCATION (*expr_p);
 607         *expr_p = build_vec_init (VEC_INIT_EXPR_SLOT (*expr_p), NULL_TREE,
 608                                   init, VEC_INIT_EXPR_VALUE_INIT (*expr_p),
 609                                   from_array,
 610                                   tf_warning_or_error);
 611         hash_set<tree> pset;
 612         cp_walk_tree (expr_p, cp_fold_r, &pset, NULL);
 613         cp_genericize_tree (expr_p, false);
 614         ret = GS_OK;
 615         input_location = loc;
 616       }
 617       break;
 618
 619     case THROW_EXPR:
 620       /* FIXME communicate throw type to back end, probably by moving
 621          THROW_EXPR into ../tree.def.  */
 622       *expr_p = TREE_OPERAND (*expr_p, 0);
 623       ret = GS_OK;
 624       break;
 625
 626     case MUST_NOT_THROW_EXPR:
 627       ret = gimplify_must_not_throw_expr (expr_p, pre_p);
 628       break;
 629
 630       /* We used to do this for MODIFY_EXPR as well, but that's unsafe; the
 631          LHS of an assignment might also be involved in the RHS, as in bug
 632          25979.  */
 633     case INIT_EXPR:
 634       cp_gimplify_init_expr (expr_p);
 635       if (TREE_CODE (*expr_p) != INIT_EXPR)
 636         return GS_OK;
 637       /* Fall through.  */
 638     case MODIFY_EXPR:
 639     modify_expr_case:
 640       {
 641         /* If the back end isn't clever enough to know that the lhs and rhs
 642            types are the same, add an explicit conversion.  */
 643         tree op0 = TREE_OPERAND (*expr_p, 0);
 644         tree op1 = TREE_OPERAND (*expr_p, 1);
 645
 646         if (!error_operand_p (op0)
 647             && !error_operand_p (op1)
 648             && (TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (op0))
 649                 || TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (op1)))
 650             && !useless_type_conversion_p (TREE_TYPE (op1), TREE_TYPE (op0)))
 651           TREE_OPERAND (*expr_p, 1) = build1 (VIEW_CONVERT_EXPR,
 652                                               TREE_TYPE (op0), op1);
 653
 654         else if (simple_empty_class_p (TREE_TYPE (op0), op1))
 655           {
 656             /* Remove any copies of empty classes.  Also drop volatile
 657                variables on the RHS to avoid infinite recursion from
 658                gimplify_expr trying to load the value.  */
 659             if (TREE_SIDE_EFFECTS (op1))
 660               {
 661                 if (TREE_THIS_VOLATILE (op1)
 662                     && (REFERENCE_CLASS_P (op1) || DECL_P (op1)))
 663                   op1 = build_fold_addr_expr (op1);
 664
 665                 gimplify_and_add (op1, pre_p);
 666               }
 667             gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p, post_p,
 668                            is_gimple_lvalue, fb_lvalue);
 669             *expr_p = TREE_OPERAND (*expr_p, 0);
 670           }
 671         /* P0145 says that the RHS is sequenced before the LHS.
 672            gimplify_modify_expr gimplifies the RHS before the LHS, but that
 673            isn't quite strong enough in two cases:
 674
 675            1) gimplify.c wants to leave a CALL_EXPR on the RHS, which would
 676            mean it's evaluated after the LHS.
 677
 678            2) the value calculation of the RHS is also sequenced before the
 679            LHS, so for scalar assignment we need to preevaluate if the
 680            RHS could be affected by LHS side-effects even if it has no
 681            side-effects of its own.  We don't need this for classes because
 682            class assignment takes its RHS by reference.  */
 683        else if (flag_strong_eval_order > 1
 684                 && TREE_CODE (*expr_p) == MODIFY_EXPR
 685                 && lvalue_has_side_effects (op0)
 686                 && (TREE_CODE (op1) == CALL_EXPR
 687                     || (SCALAR_TYPE_P (TREE_TYPE (op1))
 688                         && !TREE_CONSTANT (op1))))
 689          TREE_OPERAND (*expr_p, 1) = get_formal_tmp_var (op1, pre_p);
 690       }
 691       ret = GS_OK;
 692       break;
 693
 694     case EMPTY_CLASS_EXPR:
 695       /* We create an empty CONSTRUCTOR with RECORD_TYPE.  */
 696       *expr_p = build_constructor (TREE_TYPE (*expr_p), NULL);
 697       ret = GS_OK;
 698       break;
 699
 700     case BASELINK:
 701       *expr_p = BASELINK_FUNCTIONS (*expr_p);
 702       ret = GS_OK;
 703       break;
 704
 705     case TRY_BLOCK:
 706       genericize_try_block (expr_p);
 707       ret = GS_OK;
 708       break;
 709
 710     case HANDLER:
 711       genericize_catch_block (expr_p);
 712       ret = GS_OK;
 713       break;
 714
 715     case EH_SPEC_BLOCK:
 716       genericize_eh_spec_block (expr_p);
 717       ret = GS_OK;
 718       break;
 719
 720     case USING_STMT:
 721       gcc_unreachable ();
 722
 723     case FOR_STMT:
 724     case WHILE_STMT:
 725     case DO_STMT:
 726     case SWITCH_STMT:
 727     case CONTINUE_STMT:
 728     case BREAK_STMT:
 729       gcc_unreachable ();
 730
 731     case OMP_FOR:
 732     case OMP_SIMD:
 733     case OMP_DISTRIBUTE:
 734     case OMP_TASKLOOP:
 735       ret = cp_gimplify_omp_for (expr_p, pre_p);
 736       break;
 737
 738     case EXPR_STMT:
 739       gimplify_expr_stmt (expr_p);
 740       ret = GS_OK;
 741       break;
 742
 743     case UNARY_PLUS_EXPR:
 744       {
 745         tree arg = TREE_OPERAND (*expr_p, 0);
 746         tree type = TREE_TYPE (*expr_p);
 747         *expr_p = (TREE_TYPE (arg) != type) ? fold_convert (type, arg)
 748                                             : arg;
 749         ret = GS_OK;
 750       }
 751       break;
 752
 753     case CALL_EXPR:
 754       ret = GS_OK;
 755       if (!CALL_EXPR_FN (*expr_p))
 756         /* Internal function call.  */;
 757       else if (CALL_EXPR_REVERSE_ARGS (*expr_p))
 758         {
 759           /* This is a call to a (compound) assignment operator that used
 760              the operator syntax; gimplify the RHS first.  */
 761           gcc_assert (call_expr_nargs (*expr_p) == 2);
 762           gcc_assert (!CALL_EXPR_ORDERED_ARGS (*expr_p));
 763           enum gimplify_status t
 764             = gimplify_arg (&CALL_EXPR_ARG (*expr_p, 1), pre_p, loc);
 765           if (t == GS_ERROR)
 766             ret = GS_ERROR;
 767         }
 768       else if (CALL_EXPR_ORDERED_ARGS (*expr_p))
 769         {
 770           /* Leave the last argument for gimplify_call_expr, to avoid problems
 771              with __builtin_va_arg_pack().  */
 772           int nargs = call_expr_nargs (*expr_p) - 1;
 773           for (int i = 0; i < nargs; ++i)
 774             {
 775               enum gimplify_status t
 776                 = gimplify_arg (&CALL_EXPR_ARG (*expr_p, i), pre_p, loc);
 777               if (t == GS_ERROR)
 778                 ret = GS_ERROR;
 779             }
 780         }
 781       else if (flag_strong_eval_order
 782                && !CALL_EXPR_OPERATOR_SYNTAX (*expr_p))
 783         {
 784           /* If flag_strong_eval_order, evaluate the object argument first.  */
 785           tree fntype = TREE_TYPE (CALL_EXPR_FN (*expr_p));
 786           if (INDIRECT_TYPE_P (fntype))
 787             fntype = TREE_TYPE (fntype);
 788           if (TREE_CODE (fntype) == METHOD_TYPE)
 789             {
 790               enum gimplify_status t
 791                 = gimplify_arg (&CALL_EXPR_ARG (*expr_p, 0), pre_p, loc);
 792               if (t == GS_ERROR)
 793                 ret = GS_ERROR;
 794             }
 795         }
 796       break;
 797
 798     case RETURN_EXPR:
 799       if (TREE_OPERAND (*expr_p, 0)
 800           && (TREE_CODE (TREE_OPERAND (*expr_p, 0)) == INIT_EXPR
 801               || TREE_CODE (TREE_OPERAND (*expr_p, 0)) == MODIFY_EXPR))
 802         {
 803           expr_p = &TREE_OPERAND (*expr_p, 0);
 804           code = TREE_CODE (*expr_p);
 805           /* Avoid going through the INIT_EXPR case, which can
 806              degrade INIT_EXPRs into AGGR_INIT_EXPRs.  */
 807           goto modify_expr_case;
 808         }
 809       /* Fall through.  */
 810
 811     default:
 812       ret = (enum gimplify_status) c_gimplify_expr (expr_p, pre_p, post_p);
 813       break;
 814     }
 815
 816   /* Restore saved state.  */
 817   if (STATEMENT_CODE_P (code))
 818     current_stmt_tree ()->stmts_are_full_exprs_p
 819       = saved_stmts_are_full_exprs_p;
 820
 821   return ret;
 822 }
 823
 824 static inline bool
 825 is_invisiref_parm (const_tree t)
 826 {
 827   return ((TREE_CODE (t) == PARM_DECL || TREE_CODE (t) == RESULT_DECL)
 828           && DECL_BY_REFERENCE (t));
 829 }
 830
 831 /* Return true if the uid in both int tree maps are equal.  */
 832
 833 bool
 834 cxx_int_tree_map_hasher::equal (cxx_int_tree_map *a, cxx_int_tree_map *b)
 835 {
 836   return (a->uid == b->uid);
 837 }
 838
 839 /* Hash a UID in a cxx_int_tree_map.  */
 840
 841 unsigned int
 842 cxx_int_tree_map_hasher::hash (cxx_int_tree_map *item)
 843 {
 844   return item->uid;
 845 }
 846
 847 /* A stable comparison routine for use with splay trees and DECLs.  */
 848
 849 static int
 850 splay_tree_compare_decl_uid (splay_tree_key xa, splay_tree_key xb)
 851 {
 852   tree a = (tree) xa;
 853   tree b = (tree) xb;
 854
 855   return DECL_UID (a) - DECL_UID (b);
 856 }
 857
 858 /* OpenMP context during genericization.  */
 859
 860 struct cp_genericize_omp_taskreg
 861 {
 862   bool is_parallel;
 863   bool default_shared;
 864   struct cp_genericize_omp_taskreg *outer;
 865   splay_tree variables;
 866 };
 867
 868 /* Return true if genericization should try to determine if
 869    DECL is firstprivate or shared within task regions.  */
 870
 871 static bool
 872 omp_var_to_track (tree decl)
 873 {
 874   tree type = TREE_TYPE (decl);
 875   if (is_invisiref_parm (decl))
 876     type = TREE_TYPE (type);
 877   else if (TYPE_REF_P (type))
 878     type = TREE_TYPE (type);
 879   while (TREE_CODE (type) == ARRAY_TYPE)
 880     type = TREE_TYPE (type);
 881   if (type == error_mark_node || !CLASS_TYPE_P (type))
 882     return false;
 883   if (VAR_P (decl) && CP_DECL_THREAD_LOCAL_P (decl))
 884     return false;
 885   if (cxx_omp_predetermined_sharing (decl) != OMP_CLAUSE_DEFAULT_UNSPECIFIED)
 886     return false;
 887   return true;
 888 }
 889
 890 /* Note DECL use in OpenMP region OMP_CTX during genericization.  */
 891
 892 static void
 893 omp_cxx_notice_variable (struct cp_genericize_omp_taskreg *omp_ctx, tree decl)
 894 {
 895   splay_tree_node n = splay_tree_lookup (omp_ctx->variables,
 896                                          (splay_tree_key) decl);
 897   if (n == NULL)
 898     {
 899       int flags = OMP_CLAUSE_DEFAULT_SHARED;
 900       if (omp_ctx->outer)
 901         omp_cxx_notice_variable (omp_ctx->outer, decl);
 902       if (!omp_ctx->default_shared)
 903         {
 904           struct cp_genericize_omp_taskreg *octx;
 905
 906           for (octx = omp_ctx->outer; octx; octx = octx->outer)
 907             {
 908               n = splay_tree_lookup (octx->variables, (splay_tree_key) decl);
 909               if (n && n->value != OMP_CLAUSE_DEFAULT_SHARED)
 910                 {
 911                   flags = OMP_CLAUSE_DEFAULT_FIRSTPRIVATE;
 912                   break;
 913                 }
 914               if (octx->is_parallel)
 915                 break;
 916             }
 917           if (octx == NULL
 918               && (TREE_CODE (decl) == PARM_DECL
 919                   || (!(TREE_STATIC (decl) || DECL_EXTERNAL (decl))
 920                       && DECL_CONTEXT (decl) == current_function_decl)))
 921             flags = OMP_CLAUSE_DEFAULT_FIRSTPRIVATE;
 922           if (flags == OMP_CLAUSE_DEFAULT_FIRSTPRIVATE)
 923             {
 924               /* DECL is implicitly determined firstprivate in
 925                  the current task construct.  Ensure copy ctor and
 926                  dtor are instantiated, because during gimplification
 927                  it will be already too late.  */
 928               tree type = TREE_TYPE (decl);
 929               if (is_invisiref_parm (decl))
 930                 type = TREE_TYPE (type);
 931               else if (TYPE_REF_P (type))
 932                 type = TREE_TYPE (type);
 933               while (TREE_CODE (type) == ARRAY_TYPE)
 934                 type = TREE_TYPE (type);
 935               get_copy_ctor (type, tf_none);
 936               get_dtor (type, tf_none);
 937             }
 938         }
 939       splay_tree_insert (omp_ctx->variables, (splay_tree_key) decl, flags);
 940     }
 941 }
 942
 943 /* Genericization context.  */
 944
 945 struct cp_genericize_data
 946 {
 947   hash_set<tree> *p_set;
 948   vec<tree> bind_expr_stack;
 949   struct cp_genericize_omp_taskreg *omp_ctx;
 950   tree try_block;
 951   bool no_sanitize_p;
 952   bool handle_invisiref_parm_p;
 953 };
 954
 955 /* Perform any pre-gimplification folding of C++ front end trees to
 956    GENERIC.
 957    Note:  The folding of none-omp cases is something to move into
 958      the middle-end.  As for now we have most foldings only on GENERIC
 959      in fold-const, we need to perform this before transformation to
 960      GIMPLE-form.  */
 961
 962 static tree
 963 cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data)
 964 {
 965   tree stmt;
 966   enum tree_code code;
 967
 968   *stmt_p = stmt = cp_fold (*stmt_p);
 969
 970   if (((hash_set<tree> *) data)->add (stmt))
 971     {
 972       /* Don't walk subtrees of stmts we've already walked once, otherwise
 973          we can have exponential complexity with e.g. lots of nested
 974          SAVE_EXPRs or TARGET_EXPRs.  cp_fold uses a cache and will return
 975          always the same tree, which the first time cp_fold_r has been
 976          called on it had the subtrees walked.  */
 977       *walk_subtrees = 0;
 978       return NULL;
 979     }
 980
 981   code = TREE_CODE (stmt);
 982   if (code == OMP_FOR || code == OMP_SIMD || code == OMP_DISTRIBUTE
 983       || code == OMP_TASKLOOP || code == OACC_LOOP)
 984     {
 985       tree x;
 986       int i, n;
 987
 988       cp_walk_tree (&OMP_FOR_BODY (stmt), cp_fold_r, data, NULL);
 989       cp_walk_tree (&OMP_FOR_CLAUSES (stmt), cp_fold_r, data, NULL);
 990       cp_walk_tree (&OMP_FOR_INIT (stmt), cp_fold_r, data, NULL);
 991       x = OMP_FOR_COND (stmt);
 992       if (x && TREE_CODE_CLASS (TREE_CODE (x)) == tcc_comparison)
 993         {
 994           cp_walk_tree (&TREE_OPERAND (x, 0), cp_fold_r, data, NULL);
 995           cp_walk_tree (&TREE_OPERAND (x, 1), cp_fold_r, data, NULL);
 996         }
 997       else if (x && TREE_CODE (x) == TREE_VEC)
 998         {
 999           n = TREE_VEC_LENGTH (x);
1000           for (i = 0; i < n; i++)
1001             {
1002               tree o = TREE_VEC_ELT (x, i);
1003               if (o && TREE_CODE_CLASS (TREE_CODE (o)) == tcc_comparison)
1004                 cp_walk_tree (&TREE_OPERAND (o, 1), cp_fold_r, data, NULL);
1005             }
1006         }
1007       x = OMP_FOR_INCR (stmt);
1008       if (x && TREE_CODE (x) == TREE_VEC)
1009         {
1010           n = TREE_VEC_LENGTH (x);
1011           for (i = 0; i < n; i++)
1012             {
1013               tree o = TREE_VEC_ELT (x, i);
1014               if (o && TREE_CODE (o) == MODIFY_EXPR)
1015                 o = TREE_OPERAND (o, 1);
1016               if (o && (TREE_CODE (o) == PLUS_EXPR || TREE_CODE (o) == MINUS_EXPR
1017                         || TREE_CODE (o) == POINTER_PLUS_EXPR))
1018                 {
1019                   cp_walk_tree (&TREE_OPERAND (o, 0), cp_fold_r, data, NULL);
1020                   cp_walk_tree (&TREE_OPERAND (o, 1), cp_fold_r, data, NULL);
1021                 }
1022             }
1023         }
1024       cp_walk_tree (&OMP_FOR_PRE_BODY (stmt), cp_fold_r, data, NULL);
1025       *walk_subtrees = 0;
1026     }
1027
1028   return NULL;
1029 }
1030
1031 /* Fold ALL the trees!  FIXME we should be able to remove this, but
1032    apparently that still causes optimization regressions.  */
1033
1034 void
1035 cp_fold_function (tree fndecl)
1036 {
1037   hash_set<tree> pset;
1038   cp_walk_tree (&DECL_SAVED_TREE (fndecl), cp_fold_r, &pset, NULL);
1039 }
1040
1041 /* Perform any pre-gimplification lowering of C++ front end trees to
1042    GENERIC.  */
1043
1044 static tree
1045 cp_genericize_r (tree *stmt_p, int *walk_subtrees, void *data)
1046 {
1047   tree stmt = *stmt_p;
1048   struct cp_genericize_data *wtd = (struct cp_genericize_data *) data;
1049   hash_set<tree> *p_set = wtd->p_set;
1050
1051   /* If in an OpenMP context, note var uses.  */
1052   if (__builtin_expect (wtd->omp_ctx != NULL, 0)
1053       && (VAR_P (stmt)
1054           || TREE_CODE (stmt) == PARM_DECL
1055           || TREE_CODE (stmt) == RESULT_DECL)
1056       && omp_var_to_track (stmt))
1057     omp_cxx_notice_variable (wtd->omp_ctx, stmt);
1058
1059   /* Don't dereference parms in a thunk, pass the references through. */
1060   if ((TREE_CODE (stmt) == CALL_EXPR && CALL_FROM_THUNK_P (stmt))
1061       || (TREE_CODE (stmt) == AGGR_INIT_EXPR && AGGR_INIT_FROM_THUNK_P (stmt)))
1062     {
1063       *walk_subtrees = 0;
1064       return NULL;
1065     }
1066
1067   /* Dereference invisible reference parms.  */
1068   if (wtd->handle_invisiref_parm_p && is_invisiref_parm (stmt))
1069     {
1070       *stmt_p = convert_from_reference (stmt);
1071       p_set->add (*stmt_p);
1072       *walk_subtrees = 0;
1073       return NULL;
1074     }
1075
1076   /* Map block scope extern declarations to visible declarations with the
1077      same name and type in outer scopes if any.  */
1078   if (cp_function_chain->extern_decl_map
1079       && VAR_OR_FUNCTION_DECL_P (stmt)
1080       && DECL_EXTERNAL (stmt))
1081     {
1082       struct cxx_int_tree_map *h, in;
1083       in.uid = DECL_UID (stmt);
1084       h = cp_function_chain->extern_decl_map->find_with_hash (&in, in.uid);
1085       if (h)
1086         {
1087           *stmt_p = h->to;
1088           *walk_subtrees = 0;
1089           return NULL;
1090         }
1091     }
1092
1093   if (TREE_CODE (stmt) == INTEGER_CST
1094       && TYPE_REF_P (TREE_TYPE (stmt))
1095       && (flag_sanitize & (SANITIZE_NULL | SANITIZE_ALIGNMENT))
1096       && !wtd->no_sanitize_p)
1097     {
1098       ubsan_maybe_instrument_reference (stmt_p);
1099       if (*stmt_p != stmt)
1100         {
1101           *walk_subtrees = 0;
1102           return NULL_TREE;
1103         }
1104     }
1105
1106   /* Other than invisiref parms, don't walk the same tree twice.  */
1107   if (p_set->contains (stmt))
1108     {
1109       *walk_subtrees = 0;
1110       return NULL_TREE;
1111     }
1112
1113   switch (TREE_CODE (stmt))
1114     {
1115     case ADDR_EXPR:
1116       if (is_invisiref_parm (TREE_OPERAND (stmt, 0)))
1117         {
1118           /* If in an OpenMP context, note var uses.  */
1119           if (__builtin_expect (wtd->omp_ctx != NULL, 0)
1120               && omp_var_to_track (TREE_OPERAND (stmt, 0)))
1121             omp_cxx_notice_variable (wtd->omp_ctx, TREE_OPERAND (stmt, 0));
1122           *stmt_p = fold_convert (TREE_TYPE (stmt), TREE_OPERAND (stmt, 0));
1123           *walk_subtrees = 0;
1124         }
1125       break;
1126
1127     case RETURN_EXPR:
1128       if (TREE_OPERAND (stmt, 0) && is_invisiref_parm (TREE_OPERAND (stmt, 0)))
1129         /* Don't dereference an invisiref RESULT_DECL inside a RETURN_EXPR.  */
1130         *walk_subtrees = 0;
1131       break;
1132
1133     case OMP_CLAUSE:
1134       switch (OMP_CLAUSE_CODE (stmt))
1135         {
1136         case OMP_CLAUSE_LASTPRIVATE:
1137           /* Don't dereference an invisiref in OpenMP clauses.  */
1138           if (is_invisiref_parm (OMP_CLAUSE_DECL (stmt)))
1139             {
1140               *walk_subtrees = 0;
1141               if (OMP_CLAUSE_LASTPRIVATE_STMT (stmt))
1142                 cp_walk_tree (&OMP_CLAUSE_LASTPRIVATE_STMT (stmt),
1143                               cp_genericize_r, data, NULL);
1144             }
1145           break;
1146         case OMP_CLAUSE_PRIVATE:
1147           /* Don't dereference an invisiref in OpenMP clauses.  */
1148           if (is_invisiref_parm (OMP_CLAUSE_DECL (stmt)))
1149             *walk_subtrees = 0;
1150           else if (wtd->omp_ctx != NULL)
1151             {
1152               /* Private clause doesn't cause any references to the
1153                  var in outer contexts, avoid calling
1154                  omp_cxx_notice_variable for it.  */
1155               struct cp_genericize_omp_taskreg *old = wtd->omp_ctx;
1156               wtd->omp_ctx = NULL;
1157               cp_walk_tree (&OMP_CLAUSE_DECL (stmt), cp_genericize_r,
1158                             data, NULL);
1159               wtd->omp_ctx = old;
1160               *walk_subtrees = 0;
1161             }
1162           break;
1163         case OMP_CLAUSE_SHARED:
1164         case OMP_CLAUSE_FIRSTPRIVATE:
1165         case OMP_CLAUSE_COPYIN:
1166         case OMP_CLAUSE_COPYPRIVATE:
1167           /* Don't dereference an invisiref in OpenMP clauses.  */
1168           if (is_invisiref_parm (OMP_CLAUSE_DECL (stmt)))
1169             *walk_subtrees = 0;
1170           break;
1171         case OMP_CLAUSE_REDUCTION:
1172           /* Don't dereference an invisiref in reduction clause's
1173              OMP_CLAUSE_DECL either.  OMP_CLAUSE_REDUCTION_{INIT,MERGE}
1174              still needs to be genericized.  */
1175           if (is_invisiref_parm (OMP_CLAUSE_DECL (stmt)))
1176             {
1177               *walk_subtrees = 0;
1178               if (OMP_CLAUSE_REDUCTION_INIT (stmt))
1179                 cp_walk_tree (&OMP_CLAUSE_REDUCTION_INIT (stmt),
1180                               cp_genericize_r, data, NULL);
1181               if (OMP_CLAUSE_REDUCTION_MERGE (stmt))
1182                 cp_walk_tree (&OMP_CLAUSE_REDUCTION_MERGE (stmt),
1183                               cp_genericize_r, data, NULL);
1184             }
1185           break;
1186         default:
1187           break;
1188         }
1189       break;
1190
1191     /* Due to the way voidify_wrapper_expr is written, we don't get a chance
1192        to lower this construct before scanning it, so we need to lower these
1193        before doing anything else.  */
1194     case CLEANUP_STMT:
1195       *stmt_p = build2_loc (EXPR_LOCATION (stmt),
1196                             CLEANUP_EH_ONLY (stmt) ? TRY_CATCH_EXPR
1197                                                    : TRY_FINALLY_EXPR,
1198                             void_type_node,
1199                             CLEANUP_BODY (stmt),
1200                             CLEANUP_EXPR (stmt));
1201       break;
1202
1203     case IF_STMT:
1204       genericize_if_stmt (stmt_p);
1205       /* *stmt_p has changed, tail recurse to handle it again.  */
1206       return cp_genericize_r (stmt_p, walk_subtrees, data);
1207
1208     /* COND_EXPR might have incompatible types in branches if one or both
1209        arms are bitfields.  Fix it up now.  */
1210     case COND_EXPR:
1211       {
1212         tree type_left
1213           = (TREE_OPERAND (stmt, 1)
1214              ? is_bitfield_expr_with_lowered_type (TREE_OPERAND (stmt, 1))
1215              : NULL_TREE);
1216         tree type_right
1217           = (TREE_OPERAND (stmt, 2)
1218              ? is_bitfield_expr_with_lowered_type (TREE_OPERAND (stmt, 2))
1219              : NULL_TREE);
1220         if (type_left
1221             && !useless_type_conversion_p (TREE_TYPE (stmt),
1222                                            TREE_TYPE (TREE_OPERAND (stmt, 1))))
1223           {
1224             TREE_OPERAND (stmt, 1)
1225               = fold_convert (type_left, TREE_OPERAND (stmt, 1));
1226             gcc_assert (useless_type_conversion_p (TREE_TYPE (stmt),
1227                                                    type_left));
1228           }
1229         if (type_right
1230             && !useless_type_conversion_p (TREE_TYPE (stmt),
1231                                            TREE_TYPE (TREE_OPERAND (stmt, 2))))
1232           {
1233             TREE_OPERAND (stmt, 2)
1234               = fold_convert (type_right, TREE_OPERAND (stmt, 2));
1235             gcc_assert (useless_type_conversion_p (TREE_TYPE (stmt),
1236                                                    type_right));
1237           }
1238       }
1239       break;
1240
1241     case BIND_EXPR:
1242       if (__builtin_expect (wtd->omp_ctx != NULL, 0))
1243         {
1244           tree decl;
1245           for (decl = BIND_EXPR_VARS (stmt); decl; decl = DECL_CHAIN (decl))
1246             if (VAR_P (decl)
1247                 && !DECL_EXTERNAL (decl)
1248                 && omp_var_to_track (decl))
1249               {
1250                 splay_tree_node n
1251                   = splay_tree_lookup (wtd->omp_ctx->variables,
1252                                        (splay_tree_key) decl);
1253                 if (n == NULL)
1254                   splay_tree_insert (wtd->omp_ctx->variables,
1255                                      (splay_tree_key) decl,
1256                                      TREE_STATIC (decl)
1257                                      ? OMP_CLAUSE_DEFAULT_SHARED
1258                                      : OMP_CLAUSE_DEFAULT_PRIVATE);
1259               }
1260         }
1261       if (sanitize_flags_p (SANITIZE_NULL | SANITIZE_ALIGNMENT | SANITIZE_VPTR))
1262         {
1263           /* The point here is to not sanitize static initializers.  */
1264           bool no_sanitize_p = wtd->no_sanitize_p;
1265           wtd->no_sanitize_p = true;
1266           for (tree decl = BIND_EXPR_VARS (stmt);
1267                decl;
1268                decl = DECL_CHAIN (decl))
1269             if (VAR_P (decl)
1270                 && TREE_STATIC (decl)
1271                 && DECL_INITIAL (decl))
1272               cp_walk_tree (&DECL_INITIAL (decl), cp_genericize_r, data, NULL);
1273           wtd->no_sanitize_p = no_sanitize_p;
1274         }
1275       wtd->bind_expr_stack.safe_push (stmt);
1276       cp_walk_tree (&BIND_EXPR_BODY (stmt),
1277                     cp_genericize_r, data, NULL);
1278       wtd->bind_expr_stack.pop ();
1279       break;
1280
1281     case USING_STMT:
1282       {
1283         tree block = NULL_TREE;
1284
1285         /* Get the innermost inclosing GIMPLE_BIND that has a non NULL
1286            BLOCK, and append an IMPORTED_DECL to its
1287            BLOCK_VARS chained list.  */
1288         if (wtd->bind_expr_stack.exists ())
1289           {
1290             int i;
1291             for (i = wtd->bind_expr_stack.length () - 1; i >= 0; i--)
1292               if ((block = BIND_EXPR_BLOCK (wtd->bind_expr_stack[i])))
1293                 break;
1294           }
1295         if (block)
1296           {
1297             tree decl = TREE_OPERAND (stmt, 0);
1298             gcc_assert (decl);
1299
1300             if (undeduced_auto_decl (decl))
1301               /* Omit from the GENERIC, the back-end can't handle it.  */;
1302             else
1303               {
1304                 tree using_directive = make_node (IMPORTED_DECL);
1305                 TREE_TYPE (using_directive) = void_type_node;
1306
1307                 IMPORTED_DECL_ASSOCIATED_DECL (using_directive) = decl;
1308                 DECL_CHAIN (using_directive) = BLOCK_VARS (block);
1309                 BLOCK_VARS (block) = using_directive;
1310               }
1311           }
1312         /* The USING_STMT won't appear in GENERIC.  */
1313         *stmt_p = build1 (NOP_EXPR, void_type_node, integer_zero_node);
1314         *walk_subtrees = 0;
1315       }
1316       break;
1317
1318     case DECL_EXPR:
1319       if (TREE_CODE (DECL_EXPR_DECL (stmt)) == USING_DECL)
1320         {
1321           /* Using decls inside DECL_EXPRs are just dropped on the floor.  */
1322           *stmt_p = build1 (NOP_EXPR, void_type_node, integer_zero_node);
1323           *walk_subtrees = 0;
1324         }
1325       else
1326         {
1327           tree d = DECL_EXPR_DECL (stmt);
1328           if (VAR_P (d))
1329             gcc_assert (CP_DECL_THREAD_LOCAL_P (d) == DECL_THREAD_LOCAL_P (d));
1330         }
1331       break;
1332
1333     case OMP_PARALLEL:
1334     case OMP_TASK:
1335     case OMP_TASKLOOP:
1336       {
1337         struct cp_genericize_omp_taskreg omp_ctx;
1338         tree c, decl;
1339         splay_tree_node n;
1340
1341         *walk_subtrees = 0;
1342         cp_walk_tree (&OMP_CLAUSES (stmt), cp_genericize_r, data, NULL);
1343         omp_ctx.is_parallel = TREE_CODE (stmt) == OMP_PARALLEL;
1344         omp_ctx.default_shared = omp_ctx.is_parallel;
1345         omp_ctx.outer = wtd->omp_ctx;
1346         omp_ctx.variables = splay_tree_new (splay_tree_compare_decl_uid, 0, 0);
1347         wtd->omp_ctx = &omp_ctx;
1348         for (c = OMP_CLAUSES (stmt); c; c = OMP_CLAUSE_CHAIN (c))
1349           switch (OMP_CLAUSE_CODE (c))
1350             {
1351             case OMP_CLAUSE_SHARED:
1352             case OMP_CLAUSE_PRIVATE:
1353             case OMP_CLAUSE_FIRSTPRIVATE:
1354             case OMP_CLAUSE_LASTPRIVATE:
1355               decl = OMP_CLAUSE_DECL (c);
1356               if (decl == error_mark_node || !omp_var_to_track (decl))
1357                 break;
1358               n = splay_tree_lookup (omp_ctx.variables, (splay_tree_key) decl);
1359               if (n != NULL)
1360                 break;
1361               splay_tree_insert (omp_ctx.variables, (splay_tree_key) decl,
1362                                  OMP_CLAUSE_CODE (c) == OMP_CLAUSE_SHARED
1363                                  ? OMP_CLAUSE_DEFAULT_SHARED
1364                                  : OMP_CLAUSE_DEFAULT_PRIVATE);
1365               if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_PRIVATE && omp_ctx.outer)
1366                 omp_cxx_notice_variable (omp_ctx.outer, decl);
1367               break;
1368             case OMP_CLAUSE_DEFAULT:
1369               if (OMP_CLAUSE_DEFAULT_KIND (c) == OMP_CLAUSE_DEFAULT_SHARED)
1370                 omp_ctx.default_shared = true;
1371             default:
1372               break;
1373             }
1374         if (TREE_CODE (stmt) == OMP_TASKLOOP)
1375           genericize_omp_for_stmt (stmt_p, walk_subtrees, data);
1376         else
1377           cp_walk_tree (&OMP_BODY (stmt), cp_genericize_r, data, NULL);
1378         wtd->omp_ctx = omp_ctx.outer;
1379         splay_tree_delete (omp_ctx.variables);
1380       }
1381       break;
1382
1383     case TRY_BLOCK:
1384       {
1385         *walk_subtrees = 0;
1386         tree try_block = wtd->try_block;
1387         wtd->try_block = stmt;
1388         cp_walk_tree (&TRY_STMTS (stmt), cp_genericize_r, data, NULL);
1389         wtd->try_block = try_block;
1390         cp_walk_tree (&TRY_HANDLERS (stmt), cp_genericize_r, data, NULL);
1391       }
1392       break;
1393
1394     case MUST_NOT_THROW_EXPR:
1395       /* MUST_NOT_THROW_COND might be something else with TM.  */
1396       if (MUST_NOT_THROW_COND (stmt) == NULL_TREE)
1397         {
1398           *walk_subtrees = 0;
1399           tree try_block = wtd->try_block;
1400           wtd->try_block = stmt;
1401           cp_walk_tree (&TREE_OPERAND (stmt, 0), cp_genericize_r, data, NULL);
1402           wtd->try_block = try_block;
1403         }
1404       break;
1405
1406     case THROW_EXPR:
1407       {
1408         location_t loc = location_of (stmt);
1409         if (TREE_NO_WARNING (stmt))
1410           /* Never mind.  */;
1411         else if (wtd->try_block)
1412           {
1413             if (TREE_CODE (wtd->try_block) == MUST_NOT_THROW_EXPR
1414                 && warning_at (loc, OPT_Wterminate,
1415                                "throw will always call terminate()")
1416                 && cxx_dialect >= cxx11
1417                 && DECL_DESTRUCTOR_P (current_function_decl))
1418               inform (loc, "in C++11 destructors default to noexcept");
1419           }
1420         else
1421           {
1422             if (warn_cxx11_compat && cxx_dialect < cxx11
1423                 && DECL_DESTRUCTOR_P (current_function_decl)
1424                 && (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (current_function_decl))
1425                     == NULL_TREE)
1426                 && (get_defaulted_eh_spec (current_function_decl)
1427                     == empty_except_spec))
1428               warning_at (loc, OPT_Wc__11_compat,
1429                           "in C++11 this throw will terminate because "
1430                           "destructors default to noexcept");
1431           }
1432       }
1433       break;
1434
1435     case CONVERT_EXPR:
1436       gcc_assert (!CONVERT_EXPR_VBASE_PATH (stmt));
1437       break;
1438
1439     case FOR_STMT:
1440       genericize_for_stmt (stmt_p, walk_subtrees, data);
1441       break;
1442
1443     case WHILE_STMT:
1444       genericize_while_stmt (stmt_p, walk_subtrees, data);
1445       break;
1446
1447     case DO_STMT:
1448       genericize_do_stmt (stmt_p, walk_subtrees, data);
1449       break;
1450
1451     case SWITCH_STMT:
1452       genericize_switch_stmt (stmt_p, walk_subtrees, data);
1453       break;
1454
1455     case CONTINUE_STMT:
1456       genericize_continue_stmt (stmt_p);
1457       break;
1458
1459     case BREAK_STMT:
1460       genericize_break_stmt (stmt_p);
1461       break;
1462
1463     case OMP_FOR:
1464     case OMP_SIMD:
1465     case OMP_DISTRIBUTE:
1466     case OACC_LOOP:
1467       genericize_omp_for_stmt (stmt_p, walk_subtrees, data);
1468       break;
1469
1470     case PTRMEM_CST:
1471       /* By the time we get here we're handing off to the back end, so we don't
1472          need or want to preserve PTRMEM_CST anymore.  */
1473       *stmt_p = cplus_expand_constant (stmt);
1474       *walk_subtrees = 0;
1475       break;
1476
1477     case MEM_REF:
1478       /* For MEM_REF, make sure not to sanitize the second operand even
1479          if it has reference type.  It is just an offset with a type
1480          holding other information.  There is no other processing we
1481          need to do for INTEGER_CSTs, so just ignore the second argument
1482          unconditionally.  */
1483       cp_walk_tree (&TREE_OPERAND (stmt, 0), cp_genericize_r, data, NULL);
1484       *walk_subtrees = 0;
1485       break;
1486
1487     case NOP_EXPR:
1488       if (!wtd->no_sanitize_p
1489           && sanitize_flags_p (SANITIZE_NULL | SANITIZE_ALIGNMENT)
1490           && TYPE_REF_P (TREE_TYPE (stmt)))
1491         ubsan_maybe_instrument_reference (stmt_p);
1492       break;
1493
1494     case CALL_EXPR:
1495       if (!wtd->no_sanitize_p
1496           && sanitize_flags_p ((SANITIZE_NULL
1497                                 | SANITIZE_ALIGNMENT | SANITIZE_VPTR)))
1498         {
1499           tree fn = CALL_EXPR_FN (stmt);
1500           if (fn != NULL_TREE
1501               && !error_operand_p (fn)
1502               && INDIRECT_TYPE_P (TREE_TYPE (fn))
1503               && TREE_CODE (TREE_TYPE (TREE_TYPE (fn))) == METHOD_TYPE)
1504             {
1505               bool is_ctor
1506                 = TREE_CODE (fn) == ADDR_EXPR
1507                   && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
1508                   && DECL_CONSTRUCTOR_P (TREE_OPERAND (fn, 0));
1509               if (sanitize_flags_p (SANITIZE_NULL | SANITIZE_ALIGNMENT))
1510                 ubsan_maybe_instrument_member_call (stmt, is_ctor);
1511               if (sanitize_flags_p (SANITIZE_VPTR) && !is_ctor)
1512                 cp_ubsan_maybe_instrument_member_call (stmt);
1513             }
1514           else if (fn == NULL_TREE
1515                    && CALL_EXPR_IFN (stmt) == IFN_UBSAN_NULL
1516                    && TREE_CODE (CALL_EXPR_ARG (stmt, 0)) == INTEGER_CST
1517                    && TYPE_REF_P (TREE_TYPE (CALL_EXPR_ARG (stmt, 0))))
1518             *walk_subtrees = 0;
1519         }
1520       /* Fall through.  */
1521     case AGGR_INIT_EXPR:
1522       /* For calls to a multi-versioned function, overload resolution
1523          returns the function with the highest target priority, that is,
1524          the version that will checked for dispatching first.  If this
1525          version is inlinable, a direct call to this version can be made
1526          otherwise the call should go through the dispatcher.  */
1527       {
1528         tree fn = cp_get_callee_fndecl_nofold (stmt);
1529         if (fn && DECL_FUNCTION_VERSIONED (fn)
1530             && (current_function_decl == NULL
1531                 || !targetm.target_option.can_inline_p (current_function_decl,
1532                                                         fn)))
1533           if (tree dis = get_function_version_dispatcher (fn))
1534             {
1535               mark_versions_used (dis);
1536               dis = build_address (dis);
1537               if (TREE_CODE (stmt) == CALL_EXPR)
1538                 CALL_EXPR_FN (stmt) = dis;
1539               else
1540                 AGGR_INIT_EXPR_FN (stmt) = dis;
1541             }
1542       }
1543       break;
1544
1545     case TARGET_EXPR:
1546       if (TARGET_EXPR_INITIAL (stmt)
1547           && TREE_CODE (TARGET_EXPR_INITIAL (stmt)) == CONSTRUCTOR
1548           && CONSTRUCTOR_PLACEHOLDER_BOUNDARY (TARGET_EXPR_INITIAL (stmt)))
1549         TARGET_EXPR_NO_ELIDE (stmt) = 1;
1550       break;
1551
1552     default:
1553       if (IS_TYPE_OR_DECL_P (stmt))
1554         *walk_subtrees = 0;
1555       break;
1556     }
1557
1558   p_set->add (*stmt_p);
1559
1560   return NULL;
1561 }
1562
1563 /* Lower C++ front end trees to GENERIC in T_P.  */
1564
1565 static void
1566 cp_genericize_tree (tree* t_p, bool handle_invisiref_parm_p)
1567 {
1568   struct cp_genericize_data wtd;
1569
1570   wtd.p_set = new hash_set<tree>;
1571   wtd.bind_expr_stack.create (0);
1572   wtd.omp_ctx = NULL;
1573   wtd.try_block = NULL_TREE;
1574   wtd.no_sanitize_p = false;
1575   wtd.handle_invisiref_parm_p = handle_invisiref_parm_p;
1576   cp_walk_tree (t_p, cp_genericize_r, &wtd, NULL);
1577   delete wtd.p_set;
1578   wtd.bind_expr_stack.release ();
1579   if (sanitize_flags_p (SANITIZE_VPTR))
1580     cp_ubsan_instrument_member_accesses (t_p);
1581 }
1582
1583 /* If a function that should end with a return in non-void
1584    function doesn't obviously end with return, add ubsan
1585    instrumentation code to verify it at runtime.  If -fsanitize=return
1586    is not enabled, instrument __builtin_unreachable.  */
1587
1588 static void
1589 cp_maybe_instrument_return (tree fndecl)
1590 {
1591   if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fndecl)))
1592       || DECL_CONSTRUCTOR_P (fndecl)
1593       || DECL_DESTRUCTOR_P (fndecl)
1594       || !targetm.warn_func_return (fndecl))
1595     return;
1596
1597   if (!sanitize_flags_p (SANITIZE_RETURN, fndecl)
1598       /* Don't add __builtin_unreachable () if not optimizing, it will not
1599          improve any optimizations in that case, just break UB code.
1600          Don't add it if -fsanitize=unreachable -fno-sanitize=return either,
1601          UBSan covers this with ubsan_instrument_return above where sufficient
1602          information is provided, while the __builtin_unreachable () below
1603          if return sanitization is disabled will just result in hard to
1604          understand runtime error without location.  */
1605       && (!optimize
1606           || sanitize_flags_p (SANITIZE_UNREACHABLE, fndecl)))
1607     return;
1608
1609   tree t = DECL_SAVED_TREE (fndecl);
1610   while (t)
1611     {
1612       switch (TREE_CODE (t))
1613         {
1614         case BIND_EXPR:
1615           t = BIND_EXPR_BODY (t);
1616           continue;
1617         case TRY_FINALLY_EXPR:
1618         case CLEANUP_POINT_EXPR:
1619           t = TREE_OPERAND (t, 0);
1620           continue;
1621         case STATEMENT_LIST:
1622           {
1623             tree_stmt_iterator i = tsi_last (t);
1624             if (!tsi_end_p (i))
1625               {
1626                 t = tsi_stmt (i);
1627                 continue;
1628               }
1629           }
1630           break;
1631         case RETURN_EXPR:
1632           return;
1633         default:
1634           break;
1635         }
1636       break;
1637     }
1638   if (t == NULL_TREE)
1639     return;
1640   tree *p = &DECL_SAVED_TREE (fndecl);
1641   if (TREE_CODE (*p) == BIND_EXPR)
1642     p = &BIND_EXPR_BODY (*p);
1643
1644   location_t loc = DECL_SOURCE_LOCATION (fndecl);
1645   if (sanitize_flags_p (SANITIZE_RETURN, fndecl))
1646     t = ubsan_instrument_return (loc);
1647   else
1648     {
1649       tree fndecl = builtin_decl_explicit (BUILT_IN_UNREACHABLE);
1650       t = build_call_expr_loc (BUILTINS_LOCATION, fndecl, 0);
1651     }
1652
1653   append_to_statement_list (t, p);
1654 }
1655
1656 void
1657 cp_genericize (tree fndecl)
1658 {
1659   tree t;
1660
1661   /* Fix up the types of parms passed by invisible reference.  */
1662   for (t = DECL_ARGUMENTS (fndecl); t; t = DECL_CHAIN (t))
1663     if (TREE_ADDRESSABLE (TREE_TYPE (t)))
1664       {
1665         /* If a function's arguments are copied to create a thunk,
1666            then DECL_BY_REFERENCE will be set -- but the type of the
1667            argument will be a pointer type, so we will never get
1668            here.  */
1669         gcc_assert (!DECL_BY_REFERENCE (t));
1670         gcc_assert (DECL_ARG_TYPE (t) != TREE_TYPE (t));
1671         TREE_TYPE (t) = DECL_ARG_TYPE (t);
1672         DECL_BY_REFERENCE (t) = 1;
1673         TREE_ADDRESSABLE (t) = 0;
1674         relayout_decl (t);
1675       }
1676
1677   /* Do the same for the return value.  */
1678   if (TREE_ADDRESSABLE (TREE_TYPE (DECL_RESULT (fndecl))))
1679     {
1680       t = DECL_RESULT (fndecl);
1681       TREE_TYPE (t) = build_reference_type (TREE_TYPE (t));
1682       DECL_BY_REFERENCE (t) = 1;
1683       TREE_ADDRESSABLE (t) = 0;
1684       relayout_decl (t);
1685       if (DECL_NAME (t))
1686         {
1687           /* Adjust DECL_VALUE_EXPR of the original var.  */
1688           tree outer = outer_curly_brace_block (current_function_decl);
1689           tree var;
1690
1691           if (outer)
1692             for (var = BLOCK_VARS (outer); var; var = DECL_CHAIN (var))
1693               if (VAR_P (var)
1694                   && DECL_NAME (t) == DECL_NAME (var)
1695                   && DECL_HAS_VALUE_EXPR_P (var)
1696                   && DECL_VALUE_EXPR (var) == t)
1697                 {
1698                   tree val = convert_from_reference (t);
1699                   SET_DECL_VALUE_EXPR (var, val);
1700                   break;
1701                 }
1702         }
1703     }
1704
1705   /* If we're a clone, the body is already GIMPLE.  */
1706   if (DECL_CLONED_FUNCTION_P (fndecl))
1707     return;
1708
1709   /* Allow cp_genericize calls to be nested.  */
1710   tree save_bc_label[2];
1711   save_bc_label[bc_break] = bc_label[bc_break];
1712   save_bc_label[bc_continue] = bc_label[bc_continue];
1713   bc_label[bc_break] = NULL_TREE;
1714   bc_label[bc_continue] = NULL_TREE;
1715
1716   /* We do want to see every occurrence of the parms, so we can't just use
1717      walk_tree's hash functionality.  */
1718   cp_genericize_tree (&DECL_SAVED_TREE (fndecl), true);
1719
1720   cp_maybe_instrument_return (fndecl);
1721
1722   /* Do everything else.  */
1723   c_genericize (fndecl);
1724
1725   gcc_assert (bc_label[bc_break] == NULL);
1726   gcc_assert (bc_label[bc_continue] == NULL);
1727   bc_label[bc_break] = save_bc_label[bc_break];
1728   bc_label[bc_continue] = save_bc_label[bc_continue];
1729 }
1730 \f
1731 /* Build code to apply FN to each member of ARG1 and ARG2.  FN may be
1732    NULL if there is in fact nothing to do.  ARG2 may be null if FN
1733    actually only takes one argument.  */
1734
1735 static tree
1736 cxx_omp_clause_apply_fn (tree fn, tree arg1, tree arg2)
1737 {
1738   tree defparm, parm, t;
1739   int i = 0;
1740   int nargs;
1741   tree *argarray;
1742
1743   if (fn == NULL)
1744     return NULL;
1745
1746   nargs = list_length (DECL_ARGUMENTS (fn));
1747   argarray = XALLOCAVEC (tree, nargs);
1748
1749   defparm = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fn)));
1750   if (arg2)
1751     defparm = TREE_CHAIN (defparm);
1752
1753   bool is_method = TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE;
1754   if (TREE_CODE (TREE_TYPE (arg1)) == ARRAY_TYPE)
1755     {
1756       tree inner_type = TREE_TYPE (arg1);
1757       tree start1, end1, p1;
1758       tree start2 = NULL, p2 = NULL;
1759       tree ret = NULL, lab;
1760
1761       start1 = arg1;
1762       start2 = arg2;
1763       do
1764         {
1765           inner_type = TREE_TYPE (inner_type);
1766           start1 = build4 (ARRAY_REF, inner_type, start1,
1767                            size_zero_node, NULL, NULL);
1768           if (arg2)
1769             start2 = build4 (ARRAY_REF, inner_type, start2,
1770                              size_zero_node, NULL, NULL);
1771         }
1772       while (TREE_CODE (inner_type) == ARRAY_TYPE);
1773       start1 = build_fold_addr_expr_loc (input_location, start1);
1774       if (arg2)
1775         start2 = build_fold_addr_expr_loc (input_location, start2);
1776
1777       end1 = TYPE_SIZE_UNIT (TREE_TYPE (arg1));
1778       end1 = fold_build_pointer_plus (start1, end1);
1779
1780       p1 = create_tmp_var (TREE_TYPE (start1));
1781       t = build2 (MODIFY_EXPR, TREE_TYPE (p1), p1, start1);
1782       append_to_statement_list (t, &ret);
1783
1784       if (arg2)
1785         {
1786           p2 = create_tmp_var (TREE_TYPE (start2));
1787           t = build2 (MODIFY_EXPR, TREE_TYPE (p2), p2, start2);
1788           append_to_statement_list (t, &ret);
1789         }
1790
1791       lab = create_artificial_label (input_location);
1792       t = build1 (LABEL_EXPR, void_type_node, lab);
1793       append_to_statement_list (t, &ret);
1794
1795       argarray[i++] = p1;
1796       if (arg2)
1797         argarray[i++] = p2;
1798       /* Handle default arguments.  */
1799       for (parm = defparm; parm && parm != void_list_node;
1800            parm = TREE_CHAIN (parm), i++)
1801         argarray[i] = convert_default_arg (TREE_VALUE (parm),
1802                                            TREE_PURPOSE (parm), fn,
1803                                            i - is_method, tf_warning_or_error);
1804       t = build_call_a (fn, i, argarray);
1805       t = fold_convert (void_type_node, t);
1806       t = fold_build_cleanup_point_expr (TREE_TYPE (t), t);
1807       append_to_statement_list (t, &ret);
1808
1809       t = fold_build_pointer_plus (p1, TYPE_SIZE_UNIT (inner_type));
1810       t = build2 (MODIFY_EXPR, TREE_TYPE (p1), p1, t);
1811       append_to_statement_list (t, &ret);
1812
1813       if (arg2)
1814         {
1815           t = fold_build_pointer_plus (p2, TYPE_SIZE_UNIT (inner_type));
1816           t = build2 (MODIFY_EXPR, TREE_TYPE (p2), p2, t);
1817           append_to_statement_list (t, &ret);
1818         }
1819
1820       t = build2 (NE_EXPR, boolean_type_node, p1, end1);
1821       t = build3 (COND_EXPR, void_type_node, t, build_and_jump (&lab), NULL);
1822       append_to_statement_list (t, &ret);
1823
1824       return ret;
1825     }
1826   else
1827     {
1828       argarray[i++] = build_fold_addr_expr_loc (input_location, arg1);
1829       if (arg2)
1830         argarray[i++] = build_fold_addr_expr_loc (input_location, arg2);
1831       /* Handle default arguments.  */
1832       for (parm = defparm; parm && parm != void_list_node;
1833            parm = TREE_CHAIN (parm), i++)
1834         argarray[i] = convert_default_arg (TREE_VALUE (parm),
1835                                            TREE_PURPOSE (parm), fn,
1836                                            i - is_method, tf_warning_or_error);
1837       t = build_call_a (fn, i, argarray);
1838       t = fold_convert (void_type_node, t);
1839       return fold_build_cleanup_point_expr (TREE_TYPE (t), t);
1840     }
1841 }
1842
1843 /* Return code to initialize DECL with its default constructor, or
1844    NULL if there's nothing to do.  */
1845
1846 tree
1847 cxx_omp_clause_default_ctor (tree clause, tree decl, tree /*outer*/)
1848 {
1849   tree info = CP_OMP_CLAUSE_INFO (clause);
1850   tree ret = NULL;
1851
1852   if (info)
1853     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 0), decl, NULL);
1854
1855   return ret;
1856 }
1857
1858 /* Return code to initialize DST with a copy constructor from SRC.  */
1859
1860 tree
1861 cxx_omp_clause_copy_ctor (tree clause, tree dst, tree src)
1862 {
1863   tree info = CP_OMP_CLAUSE_INFO (clause);
1864   tree ret = NULL;
1865
1866   if (info)
1867     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 0), dst, src);
1868   if (ret == NULL)
1869     ret = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
1870
1871   return ret;
1872 }
1873
1874 /* Similarly, except use an assignment operator instead.  */
1875
1876 tree
1877 cxx_omp_clause_assign_op (tree clause, tree dst, tree src)
1878 {
1879   tree info = CP_OMP_CLAUSE_INFO (clause);
1880   tree ret = NULL;
1881
1882   if (info)
1883     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 2), dst, src);
1884   if (ret == NULL)
1885     ret = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
1886
1887   return ret;
1888 }
1889
1890 /* Return code to destroy DECL.  */
1891
1892 tree
1893 cxx_omp_clause_dtor (tree clause, tree decl)
1894 {
1895   tree info = CP_OMP_CLAUSE_INFO (clause);
1896   tree ret = NULL;
1897
1898   if (info)
1899     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 1), decl, NULL);
1900
1901   return ret;
1902 }
1903
1904 /* True if OpenMP should privatize what this DECL points to rather
1905    than the DECL itself.  */
1906
1907 bool
1908 cxx_omp_privatize_by_reference (const_tree decl)
1909 {
1910   return (TYPE_REF_P (TREE_TYPE (decl))
1911           || is_invisiref_parm (decl));
1912 }
1913
1914 /* Return true if DECL is const qualified var having no mutable member.  */
1915 bool
1916 cxx_omp_const_qual_no_mutable (tree decl)
1917 {
1918   tree type = TREE_TYPE (decl);
1919   if (TYPE_REF_P (type))
1920     {
1921       if (!is_invisiref_parm (decl))
1922         return false;
1923       type = TREE_TYPE (type);
1924
1925       if (TREE_CODE (decl) == RESULT_DECL && DECL_NAME (decl))
1926         {
1927           /* NVR doesn't preserve const qualification of the
1928              variable's type.  */
1929           tree outer = outer_curly_brace_block (current_function_decl);
1930           tree var;
1931
1932           if (outer)
1933             for (var = BLOCK_VARS (outer); var; var = DECL_CHAIN (var))
1934               if (VAR_P (var)
1935                   && DECL_NAME (decl) == DECL_NAME (var)
1936                   && (TYPE_MAIN_VARIANT (type)
1937                       == TYPE_MAIN_VARIANT (TREE_TYPE (var))))
1938                 {
1939                   if (TYPE_READONLY (TREE_TYPE (var)))
1940                     type = TREE_TYPE (var);
1941                   break;
1942                 }
1943         }
1944     }
1945
1946   if (type == error_mark_node)
1947     return false;
1948
1949   /* Variables with const-qualified type having no mutable member
1950      are predetermined shared.  */
1951   if (TYPE_READONLY (type) && !cp_has_mutable_p (type))
1952     return true;
1953
1954   return false;
1955 }
1956
1957 /* True if OpenMP sharing attribute of DECL is predetermined.  */
1958
1959 enum omp_clause_default_kind
1960 cxx_omp_predetermined_sharing_1 (tree decl)
1961 {
1962   /* Static data members are predetermined shared.  */
1963   if (TREE_STATIC (decl))
1964     {
1965       tree ctx = CP_DECL_CONTEXT (decl);
1966       if (TYPE_P (ctx) && MAYBE_CLASS_TYPE_P (ctx))
1967         return OMP_CLAUSE_DEFAULT_SHARED;
1968     }
1969
1970   /* Const qualified vars having no mutable member are predetermined
1971      shared.  */
1972   if (cxx_omp_const_qual_no_mutable (decl))
1973     return OMP_CLAUSE_DEFAULT_SHARED;
1974
1975   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
1976 }
1977
1978 /* Likewise, but also include the artificial vars.  We don't want to
1979    disallow the artificial vars being mentioned in explicit clauses,
1980    as we use artificial vars e.g. for loop constructs with random
1981    access iterators other than pointers, but during gimplification
1982    we want to treat them as predetermined.  */
1983
1984 enum omp_clause_default_kind
1985 cxx_omp_predetermined_sharing (tree decl)
1986 {
1987   enum omp_clause_default_kind ret = cxx_omp_predetermined_sharing_1 (decl);
1988   if (ret != OMP_CLAUSE_DEFAULT_UNSPECIFIED)
1989     return ret;
1990
1991   /* Predetermine artificial variables holding integral values, those
1992      are usually result of gimplify_one_sizepos or SAVE_EXPR
1993      gimplification.  */
1994   if (VAR_P (decl)
1995       && DECL_ARTIFICIAL (decl)
1996       && INTEGRAL_TYPE_P (TREE_TYPE (decl))
1997       && !(DECL_LANG_SPECIFIC (decl)
1998            && DECL_OMP_PRIVATIZED_MEMBER (decl)))
1999     return OMP_CLAUSE_DEFAULT_SHARED;
2000
2001   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
2002 }
2003
2004 /* Finalize an implicitly determined clause.  */
2005
2006 void
2007 cxx_omp_finish_clause (tree c, gimple_seq *)
2008 {
2009   tree decl, inner_type;
2010   bool make_shared = false;
2011
2012   if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_FIRSTPRIVATE)
2013     return;
2014
2015   decl = OMP_CLAUSE_DECL (c);
2016   decl = require_complete_type (decl);
2017   inner_type = TREE_TYPE (decl);
2018   if (decl == error_mark_node)
2019     make_shared = true;
2020   else if (TYPE_REF_P (TREE_TYPE (decl)))
2021     inner_type = TREE_TYPE (inner_type);
2022
2023   /* We're interested in the base element, not arrays.  */
2024   while (TREE_CODE (inner_type) == ARRAY_TYPE)
2025     inner_type = TREE_TYPE (inner_type);
2026
2027   /* Check for special function availability by building a call to one.
2028      Save the results, because later we won't be in the right context
2029      for making these queries.  */
2030   if (!make_shared
2031       && CLASS_TYPE_P (inner_type)
2032       && cxx_omp_create_clause_info (c, inner_type, false, true, false, true))
2033     make_shared = true;
2034
2035   if (make_shared)
2036     {
2037       OMP_CLAUSE_CODE (c) = OMP_CLAUSE_SHARED;
2038       OMP_CLAUSE_SHARED_FIRSTPRIVATE (c) = 0;
2039       OMP_CLAUSE_SHARED_READONLY (c) = 0;
2040     }
2041 }
2042
2043 /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
2044    disregarded in OpenMP construct, because it is going to be
2045    remapped during OpenMP lowering.  SHARED is true if DECL
2046    is going to be shared, false if it is going to be privatized.  */
2047
2048 bool
2049 cxx_omp_disregard_value_expr (tree decl, bool shared)
2050 {
2051   return !shared
2052          && VAR_P (decl)
2053          && DECL_HAS_VALUE_EXPR_P (decl)
2054          && DECL_ARTIFICIAL (decl)
2055          && DECL_LANG_SPECIFIC (decl)
2056          && DECL_OMP_PRIVATIZED_MEMBER (decl);
2057 }
2058
2059 /* Fold expression X which is used as an rvalue if RVAL is true.  */
2060
2061 static tree
2062 cp_fold_maybe_rvalue (tree x, bool rval)
2063 {
2064   while (true)
2065     {
2066       x = cp_fold (x);
2067       if (rval && DECL_P (x)
2068           && !TYPE_REF_P (TREE_TYPE (x)))
2069         {
2070           tree v = decl_constant_value (x);
2071           if (v != x && v != error_mark_node)
2072             {
2073               x = v;
2074               continue;
2075             }
2076         }
2077       break;
2078     }
2079   return x;
2080 }
2081
2082 /* Fold expression X which is used as an rvalue.  */
2083
2084 static tree
2085 cp_fold_rvalue (tree x)
2086 {
2087   return cp_fold_maybe_rvalue (x, true);
2088 }
2089
2090 /* Perform folding on expression X.  */
2091
2092 tree
2093 cp_fully_fold (tree x)
2094 {
2095   if (processing_template_decl)
2096     return x;
2097   /* FIXME cp_fold ought to be a superset of maybe_constant_value so we don't
2098      have to call both.  */
2099   if (cxx_dialect >= cxx11)
2100     {
2101       x = maybe_constant_value (x);
2102       /* Sometimes we are given a CONSTRUCTOR but the call above wraps it into
2103          a TARGET_EXPR; undo that here.  */
2104       if (TREE_CODE (x) == TARGET_EXPR)
2105         x = TARGET_EXPR_INITIAL (x);
2106       else if (TREE_CODE (x) == VIEW_CONVERT_EXPR
2107                && TREE_CODE (TREE_OPERAND (x, 0)) == CONSTRUCTOR
2108                && TREE_TYPE (TREE_OPERAND (x, 0)) == TREE_TYPE (x))
2109         x = TREE_OPERAND (x, 0);
2110     }
2111   return cp_fold_rvalue (x);
2112 }
2113
2114 /* c-common interface to cp_fold.  If IN_INIT, this is in a static initializer
2115    and certain changes are made to the folding done.  Or should be (FIXME).  We
2116    never touch maybe_const, as it is only used for the C front-end
2117    C_MAYBE_CONST_EXPR.  */
2118
2119 tree
2120 c_fully_fold (tree x, bool /*in_init*/, bool */*maybe_const*/, bool lval)
2121 {
2122   return cp_fold_maybe_rvalue (x, !lval);
2123 }
2124
2125 static GTY((deletable)) hash_map<tree, tree> *fold_cache;
2126
2127 /* Dispose of the whole FOLD_CACHE.  */
2128
2129 void
2130 clear_fold_cache (void)
2131 {
2132   if (fold_cache != NULL)
2133     fold_cache->empty ();
2134 }
2135
2136 /*  This function tries to fold an expression X.
2137     To avoid combinatorial explosion, folding results are kept in fold_cache.
2138     If X is invalid, we don't fold at all.
2139     For performance reasons we don't cache expressions representing a
2140     declaration or constant.
2141     Function returns X or its folded variant.  */
2142
2143 static tree
2144 cp_fold (tree x)
2145 {
2146   tree op0, op1, op2, op3;
2147   tree org_x = x, r = NULL_TREE;
2148   enum tree_code code;
2149   location_t loc;
2150   bool rval_ops = true;
2151
2152   if (!x || x == error_mark_node)
2153     return x;
2154
2155   if (EXPR_P (x) && (!TREE_TYPE (x) || TREE_TYPE (x) == error_mark_node))
2156     return x;
2157
2158   /* Don't bother to cache DECLs or constants.  */
2159   if (DECL_P (x) || CONSTANT_CLASS_P (x))
2160     return x;
2161
2162   if (fold_cache == NULL)
2163     fold_cache = hash_map<tree, tree>::create_ggc (101);
2164
2165   if (tree *cached = fold_cache->get (x))
2166     return *cached;
2167
2168   code = TREE_CODE (x);
2169   switch (code)
2170     {
2171     case CLEANUP_POINT_EXPR:
2172       /* Strip CLEANUP_POINT_EXPR if the expression doesn't have side
2173          effects.  */
2174       r = cp_fold_rvalue (TREE_OPERAND (x, 0));
2175       if (!TREE_SIDE_EFFECTS (r))
2176         x = r;
2177       break;
2178
2179     case SIZEOF_EXPR:
2180       x = fold_sizeof_expr (x);
2181       break;
2182
2183     case VIEW_CONVERT_EXPR:
2184       rval_ops = false;
2185       /* FALLTHRU */
2186     case CONVERT_EXPR:
2187     case NOP_EXPR:
2188     case NON_LVALUE_EXPR:
2189
2190       if (VOID_TYPE_P (TREE_TYPE (x)))
2191         {
2192           /* This is just to make sure we don't end up with casts to
2193              void from error_mark_node.  If we just return x, then
2194              cp_fold_r might fold the operand into error_mark_node and
2195              leave the conversion in the IR.  STRIP_USELESS_TYPE_CONVERSION
2196              during gimplification doesn't like such casts.
2197              Don't create a new tree if op0 != TREE_OPERAND (x, 0), the
2198              folding of the operand should be in the caches and if in cp_fold_r
2199              it will modify it in place.  */
2200           op0 = cp_fold (TREE_OPERAND (x, 0));
2201           if (op0 == error_mark_node)
2202             x = error_mark_node;
2203           break;
2204         }
2205
2206       loc = EXPR_LOCATION (x);
2207       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), rval_ops);
2208
2209       if (code == CONVERT_EXPR
2210           && SCALAR_TYPE_P (TREE_TYPE (x))
2211           && op0 != void_node)
2212         /* During parsing we used convert_to_*_nofold; re-convert now using the
2213            folding variants, since fold() doesn't do those transformations.  */
2214         x = fold (convert (TREE_TYPE (x), op0));
2215       else if (op0 != TREE_OPERAND (x, 0))
2216         {
2217           if (op0 == error_mark_node)
2218             x = error_mark_node;
2219           else
2220             x = fold_build1_loc (loc, code, TREE_TYPE (x), op0);
2221         }
2222       else
2223         x = fold (x);
2224
2225       /* Conversion of an out-of-range value has implementation-defined
2226          behavior; the language considers it different from arithmetic
2227          overflow, which is undefined.  */
2228       if (TREE_CODE (op0) == INTEGER_CST
2229           && TREE_OVERFLOW_P (x) && !TREE_OVERFLOW_P (op0))
2230         TREE_OVERFLOW (x) = false;
2231
2232       break;
2233
2234     case INDIRECT_REF:
2235       /* We don't need the decltype(auto) obfuscation anymore.  */
2236       if (REF_PARENTHESIZED_P (x))
2237         {
2238           tree p = maybe_undo_parenthesized_ref (x);
2239           return cp_fold (p);
2240         }
2241       goto unary;
2242
2243     case ADDR_EXPR:
2244       loc = EXPR_LOCATION (x);
2245       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), false);
2246
2247       /* Cope with user tricks that amount to offsetof.  */
2248       if (op0 != error_mark_node
2249           && TREE_CODE (TREE_TYPE (op0)) != FUNCTION_TYPE
2250           && TREE_CODE (TREE_TYPE (op0)) != METHOD_TYPE)
2251         {
2252           tree val = get_base_address (op0);
2253           if (val
2254               && INDIRECT_REF_P (val)
2255               && COMPLETE_TYPE_P (TREE_TYPE (val))
2256               && TREE_CONSTANT (TREE_OPERAND (val, 0)))
2257             {
2258               val = TREE_OPERAND (val, 0);
2259               STRIP_NOPS (val);
2260               if (TREE_CODE (val) == INTEGER_CST)
2261                 return fold_offsetof (op0, TREE_TYPE (x));
2262             }
2263         }
2264       goto finish_unary;
2265
2266     case REALPART_EXPR:
2267     case IMAGPART_EXPR:
2268       rval_ops = false;
2269       /* FALLTHRU */
2270     case CONJ_EXPR:
2271     case FIX_TRUNC_EXPR:
2272     case FLOAT_EXPR:
2273     case NEGATE_EXPR:
2274     case ABS_EXPR:
2275     case ABSU_EXPR:
2276     case BIT_NOT_EXPR:
2277     case TRUTH_NOT_EXPR:
2278     case FIXED_CONVERT_EXPR:
2279     unary:
2280
2281       loc = EXPR_LOCATION (x);
2282       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), rval_ops);
2283
2284     finish_unary:
2285       if (op0 != TREE_OPERAND (x, 0))
2286         {
2287           if (op0 == error_mark_node)
2288             x = error_mark_node;
2289           else
2290             {
2291               x = fold_build1_loc (loc, code, TREE_TYPE (x), op0);
2292               if (code == INDIRECT_REF
2293                   && (INDIRECT_REF_P (x) || TREE_CODE (x) == MEM_REF))
2294                 {
2295                   TREE_READONLY (x) = TREE_READONLY (org_x);
2296                   TREE_SIDE_EFFECTS (x) = TREE_SIDE_EFFECTS (org_x);
2297                   TREE_THIS_VOLATILE (x) = TREE_THIS_VOLATILE (org_x);
2298                 }
2299             }
2300         }
2301       else
2302         x = fold (x);
2303
2304       gcc_assert (TREE_CODE (x) != COND_EXPR
2305                   || !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (x, 0))));
2306       break;
2307
2308     case UNARY_PLUS_EXPR:
2309       op0 = cp_fold_rvalue (TREE_OPERAND (x, 0));
2310       if (op0 == error_mark_node)
2311         x = error_mark_node;
2312       else
2313         x = fold_convert (TREE_TYPE (x), op0);
2314       break;
2315
2316     case POSTDECREMENT_EXPR:
2317     case POSTINCREMENT_EXPR:
2318     case INIT_EXPR:
2319     case PREDECREMENT_EXPR:
2320     case PREINCREMENT_EXPR:
2321     case COMPOUND_EXPR:
2322     case MODIFY_EXPR:
2323       rval_ops = false;
2324       /* FALLTHRU */
2325     case POINTER_PLUS_EXPR:
2326     case PLUS_EXPR:
2327     case POINTER_DIFF_EXPR:
2328     case MINUS_EXPR:
2329     case MULT_EXPR:
2330     case TRUNC_DIV_EXPR:
2331     case CEIL_DIV_EXPR:
2332     case FLOOR_DIV_EXPR:
2333     case ROUND_DIV_EXPR:
2334     case TRUNC_MOD_EXPR:
2335     case CEIL_MOD_EXPR:
2336     case ROUND_MOD_EXPR:
2337     case RDIV_EXPR:
2338     case EXACT_DIV_EXPR:
2339     case MIN_EXPR:
2340     case MAX_EXPR:
2341     case LSHIFT_EXPR:
2342     case RSHIFT_EXPR:
2343     case LROTATE_EXPR:
2344     case RROTATE_EXPR:
2345     case BIT_AND_EXPR:
2346     case BIT_IOR_EXPR:
2347     case BIT_XOR_EXPR:
2348     case TRUTH_AND_EXPR:
2349     case TRUTH_ANDIF_EXPR:
2350     case TRUTH_OR_EXPR:
2351     case TRUTH_ORIF_EXPR:
2352     case TRUTH_XOR_EXPR:
2353     case LT_EXPR: case LE_EXPR:
2354     case GT_EXPR: case GE_EXPR:
2355     case EQ_EXPR: case NE_EXPR:
2356     case UNORDERED_EXPR: case ORDERED_EXPR:
2357     case UNLT_EXPR: case UNLE_EXPR:
2358     case UNGT_EXPR: case UNGE_EXPR:
2359     case UNEQ_EXPR: case LTGT_EXPR:
2360     case RANGE_EXPR: case COMPLEX_EXPR:
2361
2362       loc = EXPR_LOCATION (x);
2363       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), rval_ops);
2364       op1 = cp_fold_rvalue (TREE_OPERAND (x, 1));
2365
2366       if (op0 != TREE_OPERAND (x, 0) || op1 != TREE_OPERAND (x, 1))
2367         {
2368           if (op0 == error_mark_node || op1 == error_mark_node)
2369             x = error_mark_node;
2370           else
2371             x = fold_build2_loc (loc, code, TREE_TYPE (x), op0, op1);
2372         }
2373       else
2374         x = fold (x);
2375
2376       if (TREE_NO_WARNING (org_x)
2377           && warn_nonnull_compare
2378           && COMPARISON_CLASS_P (org_x))
2379         {
2380           if (x == error_mark_node || TREE_CODE (x) == INTEGER_CST)
2381             ;
2382           else if (COMPARISON_CLASS_P (x))
2383             TREE_NO_WARNING (x) = 1;
2384           /* Otherwise give up on optimizing these, let GIMPLE folders
2385              optimize those later on.  */
2386           else if (op0 != TREE_OPERAND (org_x, 0)
2387                    || op1 != TREE_OPERAND (org_x, 1))
2388             {
2389               x = build2_loc (loc, code, TREE_TYPE (org_x), op0, op1);
2390               TREE_NO_WARNING (x) = 1;
2391             }
2392           else
2393             x = org_x;
2394         }
2395       break;
2396
2397     case VEC_COND_EXPR:
2398     case COND_EXPR:
2399       loc = EXPR_LOCATION (x);
2400       op0 = cp_fold_rvalue (TREE_OPERAND (x, 0));
2401       op1 = cp_fold (TREE_OPERAND (x, 1));
2402       op2 = cp_fold (TREE_OPERAND (x, 2));
2403
2404       if (TREE_CODE (TREE_TYPE (x)) == BOOLEAN_TYPE)
2405         {
2406           warning_sentinel s (warn_int_in_bool_context);
2407           if (!VOID_TYPE_P (TREE_TYPE (op1)))
2408             op1 = cp_truthvalue_conversion (op1);
2409           if (!VOID_TYPE_P (TREE_TYPE (op2)))
2410             op2 = cp_truthvalue_conversion (op2);
2411         }
2412       else if (VOID_TYPE_P (TREE_TYPE (x)))
2413         {
2414           if (TREE_CODE (op0) == INTEGER_CST)
2415             {
2416               /* If the condition is constant, fold can fold away
2417                  the COND_EXPR.  If some statement-level uses of COND_EXPR
2418                  have one of the branches NULL, avoid folding crash.  */
2419               if (!op1)
2420                 op1 = build_empty_stmt (loc);
2421               if (!op2)
2422                 op2 = build_empty_stmt (loc);
2423             }
2424           else
2425             {
2426               /* Otherwise, don't bother folding a void condition, since
2427                  it can't produce a constant value.  */
2428               if (op0 != TREE_OPERAND (x, 0)
2429                   || op1 != TREE_OPERAND (x, 1)
2430                   || op2 != TREE_OPERAND (x, 2))
2431                 x = build3_loc (loc, code, TREE_TYPE (x), op0, op1, op2);
2432               break;
2433             }
2434         }
2435
2436       if (op0 != TREE_OPERAND (x, 0)
2437           || op1 != TREE_OPERAND (x, 1)
2438           || op2 != TREE_OPERAND (x, 2))
2439         {
2440           if (op0 == error_mark_node
2441               || op1 == error_mark_node
2442               || op2 == error_mark_node)
2443             x = error_mark_node;
2444           else
2445             x = fold_build3_loc (loc, code, TREE_TYPE (x), op0, op1, op2);
2446         }
2447       else
2448         x = fold (x);
2449
2450       /* A COND_EXPR might have incompatible types in branches if one or both
2451          arms are bitfields.  If folding exposed such a branch, fix it up.  */
2452       if (TREE_CODE (x) != code
2453           && x != error_mark_node
2454           && !useless_type_conversion_p (TREE_TYPE (org_x), TREE_TYPE (x)))
2455         x = fold_convert (TREE_TYPE (org_x), x);
2456
2457       break;
2458
2459     case CALL_EXPR:
2460       {
2461         int i, m, sv = optimize, nw = sv, changed = 0;
2462         tree callee = get_callee_fndecl (x);
2463
2464         /* Some built-in function calls will be evaluated at compile-time in
2465            fold ().  Set optimize to 1 when folding __builtin_constant_p inside
2466            a constexpr function so that fold_builtin_1 doesn't fold it to 0.  */
2467         if (callee && DECL_BUILT_IN (callee) && !optimize
2468             && DECL_IS_BUILTIN_CONSTANT_P (callee)
2469             && current_function_decl
2470             && DECL_DECLARED_CONSTEXPR_P (current_function_decl))
2471           nw = 1;
2472
2473         x = copy_node (x);
2474
2475         m = call_expr_nargs (x);
2476         for (i = 0; i < m; i++)
2477           {
2478             r = cp_fold (CALL_EXPR_ARG (x, i));
2479             if (r != CALL_EXPR_ARG (x, i))
2480               {
2481                 if (r == error_mark_node)
2482                   {
2483                     x = error_mark_node;
2484                     break;
2485                   }
2486                 changed = 1;
2487               }
2488             CALL_EXPR_ARG (x, i) = r;
2489           }
2490         if (x == error_mark_node)
2491           break;
2492
2493         optimize = nw;
2494         r = fold (x);
2495         optimize = sv;
2496
2497         if (TREE_CODE (r) != CALL_EXPR)
2498           {
2499             x = cp_fold (r);
2500             break;
2501           }
2502
2503         optimize = nw;
2504
2505         /* Invoke maybe_constant_value for functions declared
2506            constexpr and not called with AGGR_INIT_EXPRs.
2507            TODO:
2508            Do constexpr expansion of expressions where the call itself is not
2509            constant, but the call followed by an INDIRECT_REF is.  */
2510         if (callee && DECL_DECLARED_CONSTEXPR_P (callee)
2511             && !flag_no_inline)
2512           r = maybe_constant_value (x);
2513         optimize = sv;
2514
2515         if (TREE_CODE (r) != CALL_EXPR)
2516           {
2517             if (DECL_CONSTRUCTOR_P (callee))
2518               {
2519                 loc = EXPR_LOCATION (x);
2520                 tree s = build_fold_indirect_ref_loc (loc,
2521                                                       CALL_EXPR_ARG (x, 0));
2522                 r = build2_loc (loc, INIT_EXPR, TREE_TYPE (s), s, r);
2523               }
2524             x = r;
2525             break;
2526           }
2527
2528         if (!changed)
2529           x = org_x;
2530         break;
2531       }
2532
2533     case CONSTRUCTOR:
2534       {
2535         unsigned i;
2536         constructor_elt *p;
2537         vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (x);
2538         vec<constructor_elt, va_gc> *nelts = NULL;
2539         FOR_EACH_VEC_SAFE_ELT (elts, i, p)
2540           {
2541             tree op = cp_fold (p->value);
2542             if (op != p->value)
2543               {
2544                 if (op == error_mark_node)
2545                   {
2546                     x = error_mark_node;
2547                     vec_free (nelts);
2548                     break;
2549                   }
2550                 if (nelts == NULL)
2551                   nelts = elts->copy ();
2552                 (*nelts)[i].value = op;
2553               }
2554           }
2555         if (nelts)
2556           {
2557             x = build_constructor (TREE_TYPE (x), nelts);
2558             CONSTRUCTOR_PLACEHOLDER_BOUNDARY (x)
2559               = CONSTRUCTOR_PLACEHOLDER_BOUNDARY (org_x);
2560           }
2561         if (VECTOR_TYPE_P (TREE_TYPE (x)))
2562           x = fold (x);
2563         break;
2564       }
2565     case TREE_VEC:
2566       {
2567         bool changed = false;
2568         vec<tree, va_gc> *vec = make_tree_vector ();
2569         int i, n = TREE_VEC_LENGTH (x);
2570         vec_safe_reserve (vec, n);
2571
2572         for (i = 0; i < n; i++)
2573           {
2574             tree op = cp_fold (TREE_VEC_ELT (x, i));
2575             vec->quick_push (op);
2576             if (op != TREE_VEC_ELT (x, i))
2577               changed = true;
2578           }
2579
2580         if (changed)
2581           {
2582             r = copy_node (x);
2583             for (i = 0; i < n; i++)
2584               TREE_VEC_ELT (r, i) = (*vec)[i];
2585             x = r;
2586           }
2587
2588         release_tree_vector (vec);
2589       }
2590
2591       break;
2592
2593     case ARRAY_REF:
2594     case ARRAY_RANGE_REF:
2595
2596       loc = EXPR_LOCATION (x);
2597       op0 = cp_fold (TREE_OPERAND (x, 0));
2598       op1 = cp_fold (TREE_OPERAND (x, 1));
2599       op2 = cp_fold (TREE_OPERAND (x, 2));
2600       op3 = cp_fold (TREE_OPERAND (x, 3));
2601
2602       if (op0 != TREE_OPERAND (x, 0)
2603           || op1 != TREE_OPERAND (x, 1)
2604           || op2 != TREE_OPERAND (x, 2)
2605           || op3 != TREE_OPERAND (x, 3))
2606         {
2607           if (op0 == error_mark_node
2608               || op1 == error_mark_node
2609               || op2 == error_mark_node
2610               || op3 == error_mark_node)
2611             x = error_mark_node;
2612           else
2613             {
2614               x = build4_loc (loc, code, TREE_TYPE (x), op0, op1, op2, op3);
2615               TREE_READONLY (x) = TREE_READONLY (org_x);
2616               TREE_SIDE_EFFECTS (x) = TREE_SIDE_EFFECTS (org_x);
2617               TREE_THIS_VOLATILE (x) = TREE_THIS_VOLATILE (org_x);
2618             }
2619         }
2620
2621       x = fold (x);
2622       break;
2623
2624     case SAVE_EXPR:
2625       /* A SAVE_EXPR might contain e.g. (0 * i) + (0 * j), which, after
2626          folding, evaluates to an invariant.  In that case no need to wrap
2627          this folded tree with a SAVE_EXPR.  */
2628       r = cp_fold (TREE_OPERAND (x, 0));
2629       if (tree_invariant_p (r))
2630         x = r;
2631       break;
2632
2633     default:
2634       return org_x;
2635     }
2636
2637   fold_cache->put (org_x, x);
2638   /* Prevent that we try to fold an already folded result again.  */
2639   if (x != org_x)
2640     fold_cache->put (x, x);
2641
2642   return x;
2643 }
2644
2645 #include "gt-cp-cp-gimplify.h"