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 = 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 = 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 (POINTER_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 (TREE_CODE (type) == REFERENCE_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 (TREE_CODE (type) == REFERENCE_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       && TREE_CODE (TREE_TYPE (stmt)) == REFERENCE_TYPE
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 using_directive;
1298             gcc_assert (TREE_OPERAND (stmt, 0));
1299
1300             using_directive = make_node (IMPORTED_DECL);
1301             TREE_TYPE (using_directive) = void_type_node;
1302
1303             IMPORTED_DECL_ASSOCIATED_DECL (using_directive)
1304               = TREE_OPERAND (stmt, 0);
1305             DECL_CHAIN (using_directive) = BLOCK_VARS (block);
1306             BLOCK_VARS (block) = using_directive;
1307           }
1308         /* The USING_STMT won't appear in GENERIC.  */
1309         *stmt_p = build1 (NOP_EXPR, void_type_node, integer_zero_node);
1310         *walk_subtrees = 0;
1311       }
1312       break;
1313
1314     case DECL_EXPR:
1315       if (TREE_CODE (DECL_EXPR_DECL (stmt)) == USING_DECL)
1316         {
1317           /* Using decls inside DECL_EXPRs are just dropped on the floor.  */
1318           *stmt_p = build1 (NOP_EXPR, void_type_node, integer_zero_node);
1319           *walk_subtrees = 0;
1320         }
1321       else
1322         {
1323           tree d = DECL_EXPR_DECL (stmt);
1324           if (VAR_P (d))
1325             gcc_assert (CP_DECL_THREAD_LOCAL_P (d) == DECL_THREAD_LOCAL_P (d));
1326         }
1327       break;
1328
1329     case OMP_PARALLEL:
1330     case OMP_TASK:
1331     case OMP_TASKLOOP:
1332       {
1333         struct cp_genericize_omp_taskreg omp_ctx;
1334         tree c, decl;
1335         splay_tree_node n;
1336
1337         *walk_subtrees = 0;
1338         cp_walk_tree (&OMP_CLAUSES (stmt), cp_genericize_r, data, NULL);
1339         omp_ctx.is_parallel = TREE_CODE (stmt) == OMP_PARALLEL;
1340         omp_ctx.default_shared = omp_ctx.is_parallel;
1341         omp_ctx.outer = wtd->omp_ctx;
1342         omp_ctx.variables = splay_tree_new (splay_tree_compare_decl_uid, 0, 0);
1343         wtd->omp_ctx = &omp_ctx;
1344         for (c = OMP_CLAUSES (stmt); c; c = OMP_CLAUSE_CHAIN (c))
1345           switch (OMP_CLAUSE_CODE (c))
1346             {
1347             case OMP_CLAUSE_SHARED:
1348             case OMP_CLAUSE_PRIVATE:
1349             case OMP_CLAUSE_FIRSTPRIVATE:
1350             case OMP_CLAUSE_LASTPRIVATE:
1351               decl = OMP_CLAUSE_DECL (c);
1352               if (decl == error_mark_node || !omp_var_to_track (decl))
1353                 break;
1354               n = splay_tree_lookup (omp_ctx.variables, (splay_tree_key) decl);
1355               if (n != NULL)
1356                 break;
1357               splay_tree_insert (omp_ctx.variables, (splay_tree_key) decl,
1358                                  OMP_CLAUSE_CODE (c) == OMP_CLAUSE_SHARED
1359                                  ? OMP_CLAUSE_DEFAULT_SHARED
1360                                  : OMP_CLAUSE_DEFAULT_PRIVATE);
1361               if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_PRIVATE && omp_ctx.outer)
1362                 omp_cxx_notice_variable (omp_ctx.outer, decl);
1363               break;
1364             case OMP_CLAUSE_DEFAULT:
1365               if (OMP_CLAUSE_DEFAULT_KIND (c) == OMP_CLAUSE_DEFAULT_SHARED)
1366                 omp_ctx.default_shared = true;
1367             default:
1368               break;
1369             }
1370         if (TREE_CODE (stmt) == OMP_TASKLOOP)
1371           genericize_omp_for_stmt (stmt_p, walk_subtrees, data);
1372         else
1373           cp_walk_tree (&OMP_BODY (stmt), cp_genericize_r, data, NULL);
1374         wtd->omp_ctx = omp_ctx.outer;
1375         splay_tree_delete (omp_ctx.variables);
1376       }
1377       break;
1378
1379     case TRY_BLOCK:
1380       {
1381         *walk_subtrees = 0;
1382         tree try_block = wtd->try_block;
1383         wtd->try_block = stmt;
1384         cp_walk_tree (&TRY_STMTS (stmt), cp_genericize_r, data, NULL);
1385         wtd->try_block = try_block;
1386         cp_walk_tree (&TRY_HANDLERS (stmt), cp_genericize_r, data, NULL);
1387       }
1388       break;
1389
1390     case MUST_NOT_THROW_EXPR:
1391       /* MUST_NOT_THROW_COND might be something else with TM.  */
1392       if (MUST_NOT_THROW_COND (stmt) == NULL_TREE)
1393         {
1394           *walk_subtrees = 0;
1395           tree try_block = wtd->try_block;
1396           wtd->try_block = stmt;
1397           cp_walk_tree (&TREE_OPERAND (stmt, 0), cp_genericize_r, data, NULL);
1398           wtd->try_block = try_block;
1399         }
1400       break;
1401
1402     case THROW_EXPR:
1403       {
1404         location_t loc = location_of (stmt);
1405         if (TREE_NO_WARNING (stmt))
1406           /* Never mind.  */;
1407         else if (wtd->try_block)
1408           {
1409             if (TREE_CODE (wtd->try_block) == MUST_NOT_THROW_EXPR
1410                 && warning_at (loc, OPT_Wterminate,
1411                                "throw will always call terminate()")
1412                 && cxx_dialect >= cxx11
1413                 && DECL_DESTRUCTOR_P (current_function_decl))
1414               inform (loc, "in C++11 destructors default to noexcept");
1415           }
1416         else
1417           {
1418             if (warn_cxx11_compat && cxx_dialect < cxx11
1419                 && DECL_DESTRUCTOR_P (current_function_decl)
1420                 && (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (current_function_decl))
1421                     == NULL_TREE)
1422                 && (get_defaulted_eh_spec (current_function_decl)
1423                     == empty_except_spec))
1424               warning_at (loc, OPT_Wc__11_compat,
1425                           "in C++11 this throw will terminate because "
1426                           "destructors default to noexcept");
1427           }
1428       }
1429       break;
1430
1431     case CONVERT_EXPR:
1432       gcc_assert (!CONVERT_EXPR_VBASE_PATH (stmt));
1433       break;
1434
1435     case FOR_STMT:
1436       genericize_for_stmt (stmt_p, walk_subtrees, data);
1437       break;
1438
1439     case WHILE_STMT:
1440       genericize_while_stmt (stmt_p, walk_subtrees, data);
1441       break;
1442
1443     case DO_STMT:
1444       genericize_do_stmt (stmt_p, walk_subtrees, data);
1445       break;
1446
1447     case SWITCH_STMT:
1448       genericize_switch_stmt (stmt_p, walk_subtrees, data);
1449       break;
1450
1451     case CONTINUE_STMT:
1452       genericize_continue_stmt (stmt_p);
1453       break;
1454
1455     case BREAK_STMT:
1456       genericize_break_stmt (stmt_p);
1457       break;
1458
1459     case OMP_FOR:
1460     case OMP_SIMD:
1461     case OMP_DISTRIBUTE:
1462       genericize_omp_for_stmt (stmt_p, walk_subtrees, data);
1463       break;
1464
1465     case PTRMEM_CST:
1466       /* By the time we get here we're handing off to the back end, so we don't
1467          need or want to preserve PTRMEM_CST anymore.  */
1468       *stmt_p = cplus_expand_constant (stmt);
1469       *walk_subtrees = 0;
1470       break;
1471
1472     case MEM_REF:
1473       /* For MEM_REF, make sure not to sanitize the second operand even
1474          if it has reference type.  It is just an offset with a type
1475          holding other information.  There is no other processing we
1476          need to do for INTEGER_CSTs, so just ignore the second argument
1477          unconditionally.  */
1478       cp_walk_tree (&TREE_OPERAND (stmt, 0), cp_genericize_r, data, NULL);
1479       *walk_subtrees = 0;
1480       break;
1481
1482     case NOP_EXPR:
1483       if (!wtd->no_sanitize_p
1484           && sanitize_flags_p (SANITIZE_NULL | SANITIZE_ALIGNMENT)
1485           && TREE_CODE (TREE_TYPE (stmt)) == REFERENCE_TYPE)
1486         ubsan_maybe_instrument_reference (stmt_p);
1487       break;
1488
1489     case CALL_EXPR:
1490       if (!wtd->no_sanitize_p
1491           && sanitize_flags_p ((SANITIZE_NULL
1492                                 | SANITIZE_ALIGNMENT | SANITIZE_VPTR)))
1493         {
1494           tree fn = CALL_EXPR_FN (stmt);
1495           if (fn != NULL_TREE
1496               && !error_operand_p (fn)
1497               && POINTER_TYPE_P (TREE_TYPE (fn))
1498               && TREE_CODE (TREE_TYPE (TREE_TYPE (fn))) == METHOD_TYPE)
1499             {
1500               bool is_ctor
1501                 = TREE_CODE (fn) == ADDR_EXPR
1502                   && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
1503                   && DECL_CONSTRUCTOR_P (TREE_OPERAND (fn, 0));
1504               if (sanitize_flags_p (SANITIZE_NULL | SANITIZE_ALIGNMENT))
1505                 ubsan_maybe_instrument_member_call (stmt, is_ctor);
1506               if (sanitize_flags_p (SANITIZE_VPTR) && !is_ctor)
1507                 cp_ubsan_maybe_instrument_member_call (stmt);
1508             }
1509           else if (fn == NULL_TREE
1510                    && CALL_EXPR_IFN (stmt) == IFN_UBSAN_NULL
1511                    && TREE_CODE (CALL_EXPR_ARG (stmt, 0)) == INTEGER_CST
1512                    && (TREE_CODE (TREE_TYPE (CALL_EXPR_ARG (stmt, 0)))
1513                        == REFERENCE_TYPE))
1514             *walk_subtrees = 0;
1515         }
1516       break;
1517
1518     default:
1519       if (IS_TYPE_OR_DECL_P (stmt))
1520         *walk_subtrees = 0;
1521       break;
1522     }
1523
1524   p_set->add (*stmt_p);
1525
1526   return NULL;
1527 }
1528
1529 /* Lower C++ front end trees to GENERIC in T_P.  */
1530
1531 static void
1532 cp_genericize_tree (tree* t_p, bool handle_invisiref_parm_p)
1533 {
1534   struct cp_genericize_data wtd;
1535
1536   wtd.p_set = new hash_set<tree>;
1537   wtd.bind_expr_stack.create (0);
1538   wtd.omp_ctx = NULL;
1539   wtd.try_block = NULL_TREE;
1540   wtd.no_sanitize_p = false;
1541   wtd.handle_invisiref_parm_p = handle_invisiref_parm_p;
1542   cp_walk_tree (t_p, cp_genericize_r, &wtd, NULL);
1543   delete wtd.p_set;
1544   wtd.bind_expr_stack.release ();
1545   if (sanitize_flags_p (SANITIZE_VPTR))
1546     cp_ubsan_instrument_member_accesses (t_p);
1547 }
1548
1549 /* If a function that should end with a return in non-void
1550    function doesn't obviously end with return, add ubsan
1551    instrumentation code to verify it at runtime.  If -fsanitize=return
1552    is not enabled, instrument __builtin_unreachable.  */
1553
1554 static void
1555 cp_maybe_instrument_return (tree fndecl)
1556 {
1557   if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fndecl)))
1558       || DECL_CONSTRUCTOR_P (fndecl)
1559       || DECL_DESTRUCTOR_P (fndecl)
1560       || !targetm.warn_func_return (fndecl))
1561     return;
1562
1563   if (!sanitize_flags_p (SANITIZE_RETURN, fndecl)
1564       /* Don't add __builtin_unreachable () if not optimizing, it will not
1565          improve any optimizations in that case, just break UB code.
1566          Don't add it if -fsanitize=unreachable -fno-sanitize=return either,
1567          UBSan covers this with ubsan_instrument_return above where sufficient
1568          information is provided, while the __builtin_unreachable () below
1569          if return sanitization is disabled will just result in hard to
1570          understand runtime error without location.  */
1571       && (!optimize
1572           || sanitize_flags_p (SANITIZE_UNREACHABLE, fndecl)))
1573     return;
1574
1575   tree t = DECL_SAVED_TREE (fndecl);
1576   while (t)
1577     {
1578       switch (TREE_CODE (t))
1579         {
1580         case BIND_EXPR:
1581           t = BIND_EXPR_BODY (t);
1582           continue;
1583         case TRY_FINALLY_EXPR:
1584           t = TREE_OPERAND (t, 0);
1585           continue;
1586         case STATEMENT_LIST:
1587           {
1588             tree_stmt_iterator i = tsi_last (t);
1589             if (!tsi_end_p (i))
1590               {
1591                 t = tsi_stmt (i);
1592                 continue;
1593               }
1594           }
1595           break;
1596         case RETURN_EXPR:
1597           return;
1598         default:
1599           break;
1600         }
1601       break;
1602     }
1603   if (t == NULL_TREE)
1604     return;
1605   tree *p = &DECL_SAVED_TREE (fndecl);
1606   if (TREE_CODE (*p) == BIND_EXPR)
1607     p = &BIND_EXPR_BODY (*p);
1608
1609   location_t loc = DECL_SOURCE_LOCATION (fndecl);
1610   if (sanitize_flags_p (SANITIZE_RETURN, fndecl))
1611     t = ubsan_instrument_return (loc);
1612   else
1613     {
1614       tree fndecl = builtin_decl_explicit (BUILT_IN_UNREACHABLE);
1615       t = build_call_expr_loc (BUILTINS_LOCATION, fndecl, 0);
1616     }
1617
1618   append_to_statement_list (t, p);
1619 }
1620
1621 void
1622 cp_genericize (tree fndecl)
1623 {
1624   tree t;
1625
1626   /* Fix up the types of parms passed by invisible reference.  */
1627   for (t = DECL_ARGUMENTS (fndecl); t; t = DECL_CHAIN (t))
1628     if (TREE_ADDRESSABLE (TREE_TYPE (t)))
1629       {
1630         /* If a function's arguments are copied to create a thunk,
1631            then DECL_BY_REFERENCE will be set -- but the type of the
1632            argument will be a pointer type, so we will never get
1633            here.  */
1634         gcc_assert (!DECL_BY_REFERENCE (t));
1635         gcc_assert (DECL_ARG_TYPE (t) != TREE_TYPE (t));
1636         TREE_TYPE (t) = DECL_ARG_TYPE (t);
1637         DECL_BY_REFERENCE (t) = 1;
1638         TREE_ADDRESSABLE (t) = 0;
1639         relayout_decl (t);
1640       }
1641
1642   /* Do the same for the return value.  */
1643   if (TREE_ADDRESSABLE (TREE_TYPE (DECL_RESULT (fndecl))))
1644     {
1645       t = DECL_RESULT (fndecl);
1646       TREE_TYPE (t) = build_reference_type (TREE_TYPE (t));
1647       DECL_BY_REFERENCE (t) = 1;
1648       TREE_ADDRESSABLE (t) = 0;
1649       relayout_decl (t);
1650       if (DECL_NAME (t))
1651         {
1652           /* Adjust DECL_VALUE_EXPR of the original var.  */
1653           tree outer = outer_curly_brace_block (current_function_decl);
1654           tree var;
1655
1656           if (outer)
1657             for (var = BLOCK_VARS (outer); var; var = DECL_CHAIN (var))
1658               if (VAR_P (var)
1659                   && DECL_NAME (t) == DECL_NAME (var)
1660                   && DECL_HAS_VALUE_EXPR_P (var)
1661                   && DECL_VALUE_EXPR (var) == t)
1662                 {
1663                   tree val = convert_from_reference (t);
1664                   SET_DECL_VALUE_EXPR (var, val);
1665                   break;
1666                 }
1667         }
1668     }
1669
1670   /* If we're a clone, the body is already GIMPLE.  */
1671   if (DECL_CLONED_FUNCTION_P (fndecl))
1672     return;
1673
1674   /* Allow cp_genericize calls to be nested.  */
1675   tree save_bc_label[2];
1676   save_bc_label[bc_break] = bc_label[bc_break];
1677   save_bc_label[bc_continue] = bc_label[bc_continue];
1678   bc_label[bc_break] = NULL_TREE;
1679   bc_label[bc_continue] = NULL_TREE;
1680
1681   /* We do want to see every occurrence of the parms, so we can't just use
1682      walk_tree's hash functionality.  */
1683   cp_genericize_tree (&DECL_SAVED_TREE (fndecl), true);
1684
1685   cp_maybe_instrument_return (fndecl);
1686
1687   /* Do everything else.  */
1688   c_genericize (fndecl);
1689
1690   gcc_assert (bc_label[bc_break] == NULL);
1691   gcc_assert (bc_label[bc_continue] == NULL);
1692   bc_label[bc_break] = save_bc_label[bc_break];
1693   bc_label[bc_continue] = save_bc_label[bc_continue];
1694 }
1695 \f
1696 /* Build code to apply FN to each member of ARG1 and ARG2.  FN may be
1697    NULL if there is in fact nothing to do.  ARG2 may be null if FN
1698    actually only takes one argument.  */
1699
1700 static tree
1701 cxx_omp_clause_apply_fn (tree fn, tree arg1, tree arg2)
1702 {
1703   tree defparm, parm, t;
1704   int i = 0;
1705   int nargs;
1706   tree *argarray;
1707
1708   if (fn == NULL)
1709     return NULL;
1710
1711   nargs = list_length (DECL_ARGUMENTS (fn));
1712   argarray = XALLOCAVEC (tree, nargs);
1713
1714   defparm = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fn)));
1715   if (arg2)
1716     defparm = TREE_CHAIN (defparm);
1717
1718   bool is_method = TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE;
1719   if (TREE_CODE (TREE_TYPE (arg1)) == ARRAY_TYPE)
1720     {
1721       tree inner_type = TREE_TYPE (arg1);
1722       tree start1, end1, p1;
1723       tree start2 = NULL, p2 = NULL;
1724       tree ret = NULL, lab;
1725
1726       start1 = arg1;
1727       start2 = arg2;
1728       do
1729         {
1730           inner_type = TREE_TYPE (inner_type);
1731           start1 = build4 (ARRAY_REF, inner_type, start1,
1732                            size_zero_node, NULL, NULL);
1733           if (arg2)
1734             start2 = build4 (ARRAY_REF, inner_type, start2,
1735                              size_zero_node, NULL, NULL);
1736         }
1737       while (TREE_CODE (inner_type) == ARRAY_TYPE);
1738       start1 = build_fold_addr_expr_loc (input_location, start1);
1739       if (arg2)
1740         start2 = build_fold_addr_expr_loc (input_location, start2);
1741
1742       end1 = TYPE_SIZE_UNIT (TREE_TYPE (arg1));
1743       end1 = fold_build_pointer_plus (start1, end1);
1744
1745       p1 = create_tmp_var (TREE_TYPE (start1));
1746       t = build2 (MODIFY_EXPR, TREE_TYPE (p1), p1, start1);
1747       append_to_statement_list (t, &ret);
1748
1749       if (arg2)
1750         {
1751           p2 = create_tmp_var (TREE_TYPE (start2));
1752           t = build2 (MODIFY_EXPR, TREE_TYPE (p2), p2, start2);
1753           append_to_statement_list (t, &ret);
1754         }
1755
1756       lab = create_artificial_label (input_location);
1757       t = build1 (LABEL_EXPR, void_type_node, lab);
1758       append_to_statement_list (t, &ret);
1759
1760       argarray[i++] = p1;
1761       if (arg2)
1762         argarray[i++] = p2;
1763       /* Handle default arguments.  */
1764       for (parm = defparm; parm && parm != void_list_node;
1765            parm = TREE_CHAIN (parm), i++)
1766         argarray[i] = convert_default_arg (TREE_VALUE (parm),
1767                                            TREE_PURPOSE (parm), fn,
1768                                            i - is_method, tf_warning_or_error);
1769       t = build_call_a (fn, i, argarray);
1770       t = fold_convert (void_type_node, t);
1771       t = fold_build_cleanup_point_expr (TREE_TYPE (t), t);
1772       append_to_statement_list (t, &ret);
1773
1774       t = fold_build_pointer_plus (p1, TYPE_SIZE_UNIT (inner_type));
1775       t = build2 (MODIFY_EXPR, TREE_TYPE (p1), p1, t);
1776       append_to_statement_list (t, &ret);
1777
1778       if (arg2)
1779         {
1780           t = fold_build_pointer_plus (p2, TYPE_SIZE_UNIT (inner_type));
1781           t = build2 (MODIFY_EXPR, TREE_TYPE (p2), p2, t);
1782           append_to_statement_list (t, &ret);
1783         }
1784
1785       t = build2 (NE_EXPR, boolean_type_node, p1, end1);
1786       t = build3 (COND_EXPR, void_type_node, t, build_and_jump (&lab), NULL);
1787       append_to_statement_list (t, &ret);
1788
1789       return ret;
1790     }
1791   else
1792     {
1793       argarray[i++] = build_fold_addr_expr_loc (input_location, arg1);
1794       if (arg2)
1795         argarray[i++] = build_fold_addr_expr_loc (input_location, arg2);
1796       /* Handle default arguments.  */
1797       for (parm = defparm; parm && parm != void_list_node;
1798            parm = TREE_CHAIN (parm), i++)
1799         argarray[i] = convert_default_arg (TREE_VALUE (parm),
1800                                            TREE_PURPOSE (parm), fn,
1801                                            i - is_method, tf_warning_or_error);
1802       t = build_call_a (fn, i, argarray);
1803       t = fold_convert (void_type_node, t);
1804       return fold_build_cleanup_point_expr (TREE_TYPE (t), t);
1805     }
1806 }
1807
1808 /* Return code to initialize DECL with its default constructor, or
1809    NULL if there's nothing to do.  */
1810
1811 tree
1812 cxx_omp_clause_default_ctor (tree clause, tree decl, tree /*outer*/)
1813 {
1814   tree info = CP_OMP_CLAUSE_INFO (clause);
1815   tree ret = NULL;
1816
1817   if (info)
1818     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 0), decl, NULL);
1819
1820   return ret;
1821 }
1822
1823 /* Return code to initialize DST with a copy constructor from SRC.  */
1824
1825 tree
1826 cxx_omp_clause_copy_ctor (tree clause, tree dst, tree src)
1827 {
1828   tree info = CP_OMP_CLAUSE_INFO (clause);
1829   tree ret = NULL;
1830
1831   if (info)
1832     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 0), dst, src);
1833   if (ret == NULL)
1834     ret = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
1835
1836   return ret;
1837 }
1838
1839 /* Similarly, except use an assignment operator instead.  */
1840
1841 tree
1842 cxx_omp_clause_assign_op (tree clause, tree dst, tree src)
1843 {
1844   tree info = CP_OMP_CLAUSE_INFO (clause);
1845   tree ret = NULL;
1846
1847   if (info)
1848     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 2), dst, src);
1849   if (ret == NULL)
1850     ret = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
1851
1852   return ret;
1853 }
1854
1855 /* Return code to destroy DECL.  */
1856
1857 tree
1858 cxx_omp_clause_dtor (tree clause, tree decl)
1859 {
1860   tree info = CP_OMP_CLAUSE_INFO (clause);
1861   tree ret = NULL;
1862
1863   if (info)
1864     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 1), decl, NULL);
1865
1866   return ret;
1867 }
1868
1869 /* True if OpenMP should privatize what this DECL points to rather
1870    than the DECL itself.  */
1871
1872 bool
1873 cxx_omp_privatize_by_reference (const_tree decl)
1874 {
1875   return (TREE_CODE (TREE_TYPE (decl)) == REFERENCE_TYPE
1876           || is_invisiref_parm (decl));
1877 }
1878
1879 /* Return true if DECL is const qualified var having no mutable member.  */
1880 bool
1881 cxx_omp_const_qual_no_mutable (tree decl)
1882 {
1883   tree type = TREE_TYPE (decl);
1884   if (TREE_CODE (type) == REFERENCE_TYPE)
1885     {
1886       if (!is_invisiref_parm (decl))
1887         return false;
1888       type = TREE_TYPE (type);
1889
1890       if (TREE_CODE (decl) == RESULT_DECL && DECL_NAME (decl))
1891         {
1892           /* NVR doesn't preserve const qualification of the
1893              variable's type.  */
1894           tree outer = outer_curly_brace_block (current_function_decl);
1895           tree var;
1896
1897           if (outer)
1898             for (var = BLOCK_VARS (outer); var; var = DECL_CHAIN (var))
1899               if (VAR_P (var)
1900                   && DECL_NAME (decl) == DECL_NAME (var)
1901                   && (TYPE_MAIN_VARIANT (type)
1902                       == TYPE_MAIN_VARIANT (TREE_TYPE (var))))
1903                 {
1904                   if (TYPE_READONLY (TREE_TYPE (var)))
1905                     type = TREE_TYPE (var);
1906                   break;
1907                 }
1908         }
1909     }
1910
1911   if (type == error_mark_node)
1912     return false;
1913
1914   /* Variables with const-qualified type having no mutable member
1915      are predetermined shared.  */
1916   if (TYPE_READONLY (type) && !cp_has_mutable_p (type))
1917     return true;
1918
1919   return false;
1920 }
1921
1922 /* True if OpenMP sharing attribute of DECL is predetermined.  */
1923
1924 enum omp_clause_default_kind
1925 cxx_omp_predetermined_sharing (tree decl)
1926 {
1927   /* Static data members are predetermined shared.  */
1928   if (TREE_STATIC (decl))
1929     {
1930       tree ctx = CP_DECL_CONTEXT (decl);
1931       if (TYPE_P (ctx) && MAYBE_CLASS_TYPE_P (ctx))
1932         return OMP_CLAUSE_DEFAULT_SHARED;
1933     }
1934
1935   /* Const qualified vars having no mutable member are predetermined
1936      shared.  */
1937   if (cxx_omp_const_qual_no_mutable (decl))
1938     return OMP_CLAUSE_DEFAULT_SHARED;
1939
1940   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
1941 }
1942
1943 /* Finalize an implicitly determined clause.  */
1944
1945 void
1946 cxx_omp_finish_clause (tree c, gimple_seq *)
1947 {
1948   tree decl, inner_type;
1949   bool make_shared = false;
1950
1951   if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_FIRSTPRIVATE)
1952     return;
1953
1954   decl = OMP_CLAUSE_DECL (c);
1955   decl = require_complete_type (decl);
1956   inner_type = TREE_TYPE (decl);
1957   if (decl == error_mark_node)
1958     make_shared = true;
1959   else if (TREE_CODE (TREE_TYPE (decl)) == REFERENCE_TYPE)
1960     inner_type = TREE_TYPE (inner_type);
1961
1962   /* We're interested in the base element, not arrays.  */
1963   while (TREE_CODE (inner_type) == ARRAY_TYPE)
1964     inner_type = TREE_TYPE (inner_type);
1965
1966   /* Check for special function availability by building a call to one.
1967      Save the results, because later we won't be in the right context
1968      for making these queries.  */
1969   if (!make_shared
1970       && CLASS_TYPE_P (inner_type)
1971       && cxx_omp_create_clause_info (c, inner_type, false, true, false, true))
1972     make_shared = true;
1973
1974   if (make_shared)
1975     {
1976       OMP_CLAUSE_CODE (c) = OMP_CLAUSE_SHARED;
1977       OMP_CLAUSE_SHARED_FIRSTPRIVATE (c) = 0;
1978       OMP_CLAUSE_SHARED_READONLY (c) = 0;
1979     }
1980 }
1981
1982 /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
1983    disregarded in OpenMP construct, because it is going to be
1984    remapped during OpenMP lowering.  SHARED is true if DECL
1985    is going to be shared, false if it is going to be privatized.  */
1986
1987 bool
1988 cxx_omp_disregard_value_expr (tree decl, bool shared)
1989 {
1990   return !shared
1991          && VAR_P (decl)
1992          && DECL_HAS_VALUE_EXPR_P (decl)
1993          && DECL_ARTIFICIAL (decl)
1994          && DECL_LANG_SPECIFIC (decl)
1995          && DECL_OMP_PRIVATIZED_MEMBER (decl);
1996 }
1997
1998 /* Fold expression X which is used as an rvalue if RVAL is true.  */
1999
2000 static tree
2001 cp_fold_maybe_rvalue (tree x, bool rval)
2002 {
2003   while (true)
2004     {
2005       x = cp_fold (x);
2006       if (rval && DECL_P (x)
2007           && TREE_CODE (TREE_TYPE (x)) != REFERENCE_TYPE)
2008         {
2009           tree v = decl_constant_value (x);
2010           if (v != x && v != error_mark_node)
2011             {
2012               x = v;
2013               continue;
2014             }
2015         }
2016       break;
2017     }
2018   return x;
2019 }
2020
2021 /* Fold expression X which is used as an rvalue.  */
2022
2023 static tree
2024 cp_fold_rvalue (tree x)
2025 {
2026   return cp_fold_maybe_rvalue (x, true);
2027 }
2028
2029 /* Perform folding on expression X.  */
2030
2031 tree
2032 cp_fully_fold (tree x)
2033 {
2034   if (processing_template_decl)
2035     return x;
2036   /* FIXME cp_fold ought to be a superset of maybe_constant_value so we don't
2037      have to call both.  */
2038   if (cxx_dialect >= cxx11)
2039     x = maybe_constant_value (x);
2040   return cp_fold_rvalue (x);
2041 }
2042
2043 /* c-common interface to cp_fold.  If IN_INIT, this is in a static initializer
2044    and certain changes are made to the folding done.  Or should be (FIXME).  We
2045    never touch maybe_const, as it is only used for the C front-end
2046    C_MAYBE_CONST_EXPR.  */
2047
2048 tree
2049 c_fully_fold (tree x, bool /*in_init*/, bool */*maybe_const*/, bool lval)
2050 {
2051   return cp_fold_maybe_rvalue (x, !lval);
2052 }
2053
2054 static GTY((deletable)) hash_map<tree, tree> *fold_cache;
2055
2056 /* Dispose of the whole FOLD_CACHE.  */
2057
2058 void
2059 clear_fold_cache (void)
2060 {
2061   if (fold_cache != NULL)
2062     fold_cache->empty ();
2063 }
2064
2065 /*  This function tries to fold an expression X.
2066     To avoid combinatorial explosion, folding results are kept in fold_cache.
2067     If X is invalid, we don't fold at all.
2068     For performance reasons we don't cache expressions representing a
2069     declaration or constant.
2070     Function returns X or its folded variant.  */
2071
2072 static tree
2073 cp_fold (tree x)
2074 {
2075   tree op0, op1, op2, op3;
2076   tree org_x = x, r = NULL_TREE;
2077   enum tree_code code;
2078   location_t loc;
2079   bool rval_ops = true;
2080
2081   if (!x || x == error_mark_node)
2082     return x;
2083
2084   if (EXPR_P (x) && (!TREE_TYPE (x) || TREE_TYPE (x) == error_mark_node))
2085     return x;
2086
2087   /* Don't bother to cache DECLs or constants.  */
2088   if (DECL_P (x) || CONSTANT_CLASS_P (x))
2089     return x;
2090
2091   if (fold_cache == NULL)
2092     fold_cache = hash_map<tree, tree>::create_ggc (101);
2093
2094   if (tree *cached = fold_cache->get (x))
2095     return *cached;
2096
2097   code = TREE_CODE (x);
2098   switch (code)
2099     {
2100     case CLEANUP_POINT_EXPR:
2101       /* Strip CLEANUP_POINT_EXPR if the expression doesn't have side
2102          effects.  */
2103       r = cp_fold_rvalue (TREE_OPERAND (x, 0));
2104       if (!TREE_SIDE_EFFECTS (r))
2105         x = r;
2106       break;
2107
2108     case SIZEOF_EXPR:
2109       x = fold_sizeof_expr (x);
2110       break;
2111
2112     case VIEW_CONVERT_EXPR:
2113       rval_ops = false;
2114       /* FALLTHRU */
2115     case CONVERT_EXPR:
2116     case NOP_EXPR:
2117     case NON_LVALUE_EXPR:
2118
2119       if (VOID_TYPE_P (TREE_TYPE (x)))
2120         {
2121           /* This is just to make sure we don't end up with casts to
2122              void from error_mark_node.  If we just return x, then
2123              cp_fold_r might fold the operand into error_mark_node and
2124              leave the conversion in the IR.  STRIP_USELESS_TYPE_CONVERSION
2125              during gimplification doesn't like such casts.
2126              Don't create a new tree if op0 != TREE_OPERAND (x, 0), the
2127              folding of the operand should be in the caches and if in cp_fold_r
2128              it will modify it in place.  */
2129           op0 = cp_fold (TREE_OPERAND (x, 0));
2130           if (op0 == error_mark_node)
2131             x = error_mark_node;
2132           break;
2133         }
2134
2135       loc = EXPR_LOCATION (x);
2136       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), rval_ops);
2137
2138       if (code == CONVERT_EXPR
2139           && SCALAR_TYPE_P (TREE_TYPE (x))
2140           && op0 != void_node)
2141         /* During parsing we used convert_to_*_nofold; re-convert now using the
2142            folding variants, since fold() doesn't do those transformations.  */
2143         x = fold (convert (TREE_TYPE (x), op0));
2144       else if (op0 != TREE_OPERAND (x, 0))
2145         {
2146           if (op0 == error_mark_node)
2147             x = error_mark_node;
2148           else
2149             x = fold_build1_loc (loc, code, TREE_TYPE (x), op0);
2150         }
2151       else
2152         x = fold (x);
2153
2154       /* Conversion of an out-of-range value has implementation-defined
2155          behavior; the language considers it different from arithmetic
2156          overflow, which is undefined.  */
2157       if (TREE_CODE (op0) == INTEGER_CST
2158           && TREE_OVERFLOW_P (x) && !TREE_OVERFLOW_P (op0))
2159         TREE_OVERFLOW (x) = false;
2160
2161       break;
2162
2163     case INDIRECT_REF:
2164       /* We don't need the decltype(auto) obfuscation anymore.  */
2165       if (REF_PARENTHESIZED_P (x))
2166         {
2167           tree p = maybe_undo_parenthesized_ref (x);
2168           return cp_fold (p);
2169         }
2170       goto unary;
2171
2172     case ADDR_EXPR:
2173     case REALPART_EXPR:
2174     case IMAGPART_EXPR:
2175       rval_ops = false;
2176       /* FALLTHRU */
2177     case CONJ_EXPR:
2178     case FIX_TRUNC_EXPR:
2179     case FLOAT_EXPR:
2180     case NEGATE_EXPR:
2181     case ABS_EXPR:
2182     case BIT_NOT_EXPR:
2183     case TRUTH_NOT_EXPR:
2184     case FIXED_CONVERT_EXPR:
2185     unary:
2186
2187       loc = EXPR_LOCATION (x);
2188       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), rval_ops);
2189
2190       if (op0 != TREE_OPERAND (x, 0))
2191         {
2192           if (op0 == error_mark_node)
2193             x = error_mark_node;
2194           else
2195             {
2196               x = fold_build1_loc (loc, code, TREE_TYPE (x), op0);
2197               if (code == INDIRECT_REF
2198                   && (INDIRECT_REF_P (x) || TREE_CODE (x) == MEM_REF))
2199                 {
2200                   TREE_READONLY (x) = TREE_READONLY (org_x);
2201                   TREE_SIDE_EFFECTS (x) = TREE_SIDE_EFFECTS (org_x);
2202                   TREE_THIS_VOLATILE (x) = TREE_THIS_VOLATILE (org_x);
2203                 }
2204             }
2205         }
2206       else
2207         x = fold (x);
2208
2209       gcc_assert (TREE_CODE (x) != COND_EXPR
2210                   || !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (x, 0))));
2211       break;
2212
2213     case UNARY_PLUS_EXPR:
2214       op0 = cp_fold_rvalue (TREE_OPERAND (x, 0));
2215       if (op0 == error_mark_node)
2216         x = error_mark_node;
2217       else
2218         x = fold_convert (TREE_TYPE (x), op0);
2219       break;
2220
2221     case POSTDECREMENT_EXPR:
2222     case POSTINCREMENT_EXPR:
2223     case INIT_EXPR:
2224     case PREDECREMENT_EXPR:
2225     case PREINCREMENT_EXPR:
2226     case COMPOUND_EXPR:
2227     case MODIFY_EXPR:
2228       rval_ops = false;
2229       /* FALLTHRU */
2230     case POINTER_PLUS_EXPR:
2231     case PLUS_EXPR:
2232     case POINTER_DIFF_EXPR:
2233     case MINUS_EXPR:
2234     case MULT_EXPR:
2235     case TRUNC_DIV_EXPR:
2236     case CEIL_DIV_EXPR:
2237     case FLOOR_DIV_EXPR:
2238     case ROUND_DIV_EXPR:
2239     case TRUNC_MOD_EXPR:
2240     case CEIL_MOD_EXPR:
2241     case ROUND_MOD_EXPR:
2242     case RDIV_EXPR:
2243     case EXACT_DIV_EXPR:
2244     case MIN_EXPR:
2245     case MAX_EXPR:
2246     case LSHIFT_EXPR:
2247     case RSHIFT_EXPR:
2248     case LROTATE_EXPR:
2249     case RROTATE_EXPR:
2250     case BIT_AND_EXPR:
2251     case BIT_IOR_EXPR:
2252     case BIT_XOR_EXPR:
2253     case TRUTH_AND_EXPR:
2254     case TRUTH_ANDIF_EXPR:
2255     case TRUTH_OR_EXPR:
2256     case TRUTH_ORIF_EXPR:
2257     case TRUTH_XOR_EXPR:
2258     case LT_EXPR: case LE_EXPR:
2259     case GT_EXPR: case GE_EXPR:
2260     case EQ_EXPR: case NE_EXPR:
2261     case UNORDERED_EXPR: case ORDERED_EXPR:
2262     case UNLT_EXPR: case UNLE_EXPR:
2263     case UNGT_EXPR: case UNGE_EXPR:
2264     case UNEQ_EXPR: case LTGT_EXPR:
2265     case RANGE_EXPR: case COMPLEX_EXPR:
2266
2267       loc = EXPR_LOCATION (x);
2268       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), rval_ops);
2269       op1 = cp_fold_rvalue (TREE_OPERAND (x, 1));
2270
2271       if (op0 != TREE_OPERAND (x, 0) || op1 != TREE_OPERAND (x, 1))
2272         {
2273           if (op0 == error_mark_node || op1 == error_mark_node)
2274             x = error_mark_node;
2275           else
2276             x = fold_build2_loc (loc, code, TREE_TYPE (x), op0, op1);
2277         }
2278       else
2279         x = fold (x);
2280
2281       if (TREE_NO_WARNING (org_x)
2282           && warn_nonnull_compare
2283           && COMPARISON_CLASS_P (org_x))
2284         {
2285           if (x == error_mark_node || TREE_CODE (x) == INTEGER_CST)
2286             ;
2287           else if (COMPARISON_CLASS_P (x))
2288             TREE_NO_WARNING (x) = 1;
2289           /* Otherwise give up on optimizing these, let GIMPLE folders
2290              optimize those later on.  */
2291           else if (op0 != TREE_OPERAND (org_x, 0)
2292                    || op1 != TREE_OPERAND (org_x, 1))
2293             {
2294               x = build2_loc (loc, code, TREE_TYPE (org_x), op0, op1);
2295               TREE_NO_WARNING (x) = 1;
2296             }
2297           else
2298             x = org_x;
2299         }
2300       break;
2301
2302     case VEC_COND_EXPR:
2303     case COND_EXPR:
2304       loc = EXPR_LOCATION (x);
2305       op0 = cp_fold_rvalue (TREE_OPERAND (x, 0));
2306       op1 = cp_fold (TREE_OPERAND (x, 1));
2307       op2 = cp_fold (TREE_OPERAND (x, 2));
2308
2309       if (TREE_CODE (TREE_TYPE (x)) == BOOLEAN_TYPE)
2310         {
2311           warning_sentinel s (warn_int_in_bool_context);
2312           if (!VOID_TYPE_P (TREE_TYPE (op1)))
2313             op1 = cp_truthvalue_conversion (op1);
2314           if (!VOID_TYPE_P (TREE_TYPE (op2)))
2315             op2 = cp_truthvalue_conversion (op2);
2316         }
2317       else if (VOID_TYPE_P (TREE_TYPE (x)))
2318         {
2319           if (TREE_CODE (op0) == INTEGER_CST)
2320             {
2321               /* If the condition is constant, fold can fold away
2322                  the COND_EXPR.  If some statement-level uses of COND_EXPR
2323                  have one of the branches NULL, avoid folding crash.  */
2324               if (!op1)
2325                 op1 = build_empty_stmt (loc);
2326               if (!op2)
2327                 op2 = build_empty_stmt (loc);
2328             }
2329           else
2330             {
2331               /* Otherwise, don't bother folding a void condition, since
2332                  it can't produce a constant value.  */
2333               if (op0 != TREE_OPERAND (x, 0)
2334                   || op1 != TREE_OPERAND (x, 1)
2335                   || op2 != TREE_OPERAND (x, 2))
2336                 x = build3_loc (loc, code, TREE_TYPE (x), op0, op1, op2);
2337               break;
2338             }
2339         }
2340
2341       if (op0 != TREE_OPERAND (x, 0)
2342           || op1 != TREE_OPERAND (x, 1)
2343           || op2 != TREE_OPERAND (x, 2))
2344         {
2345           if (op0 == error_mark_node
2346               || op1 == error_mark_node
2347               || op2 == error_mark_node)
2348             x = error_mark_node;
2349           else
2350             x = fold_build3_loc (loc, code, TREE_TYPE (x), op0, op1, op2);
2351         }
2352       else
2353         x = fold (x);
2354
2355       /* A COND_EXPR might have incompatible types in branches if one or both
2356          arms are bitfields.  If folding exposed such a branch, fix it up.  */
2357       if (TREE_CODE (x) != code
2358           && !useless_type_conversion_p (TREE_TYPE (org_x), TREE_TYPE (x)))
2359         x = fold_convert (TREE_TYPE (org_x), x);
2360
2361       break;
2362
2363     case CALL_EXPR:
2364       {
2365         int i, m, sv = optimize, nw = sv, changed = 0;
2366         tree callee = get_callee_fndecl (x);
2367
2368         /* Some built-in function calls will be evaluated at compile-time in
2369            fold ().  Set optimize to 1 when folding __builtin_constant_p inside
2370            a constexpr function so that fold_builtin_1 doesn't fold it to 0.  */
2371         if (callee && DECL_BUILT_IN (callee) && !optimize
2372             && DECL_IS_BUILTIN_CONSTANT_P (callee)
2373             && current_function_decl
2374             && DECL_DECLARED_CONSTEXPR_P (current_function_decl))
2375           nw = 1;
2376
2377         x = copy_node (x);
2378
2379         m = call_expr_nargs (x);
2380         for (i = 0; i < m; i++)
2381           {
2382             r = cp_fold (CALL_EXPR_ARG (x, i));
2383             if (r != CALL_EXPR_ARG (x, i))
2384               {
2385                 if (r == error_mark_node)
2386                   {
2387                     x = error_mark_node;
2388                     break;
2389                   }
2390                 changed = 1;
2391               }
2392             CALL_EXPR_ARG (x, i) = r;
2393           }
2394         if (x == error_mark_node)
2395           break;
2396
2397         optimize = nw;
2398         r = fold (x);
2399         optimize = sv;
2400
2401         if (TREE_CODE (r) != CALL_EXPR)
2402           {
2403             x = cp_fold (r);
2404             break;
2405           }
2406
2407         optimize = nw;
2408
2409         /* Invoke maybe_constant_value for functions declared
2410            constexpr and not called with AGGR_INIT_EXPRs.
2411            TODO:
2412            Do constexpr expansion of expressions where the call itself is not
2413            constant, but the call followed by an INDIRECT_REF is.  */
2414         if (callee && DECL_DECLARED_CONSTEXPR_P (callee)
2415             && !flag_no_inline)
2416           r = maybe_constant_value (x);
2417         optimize = sv;
2418
2419         if (TREE_CODE (r) != CALL_EXPR)
2420           {
2421             if (DECL_CONSTRUCTOR_P (callee))
2422               {
2423                 loc = EXPR_LOCATION (x);
2424                 tree s = build_fold_indirect_ref_loc (loc,
2425                                                       CALL_EXPR_ARG (x, 0));
2426                 r = build2_loc (loc, INIT_EXPR, TREE_TYPE (s), s, r);
2427               }
2428             x = r;
2429             break;
2430           }
2431
2432         if (!changed)
2433           x = org_x;
2434         break;
2435       }
2436
2437     case CONSTRUCTOR:
2438       {
2439         unsigned i;
2440         constructor_elt *p;
2441         vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (x);
2442         vec<constructor_elt, va_gc> *nelts = NULL;
2443         FOR_EACH_VEC_SAFE_ELT (elts, i, p)
2444           {
2445             tree op = cp_fold (p->value);
2446             if (op != p->value)
2447               {
2448                 if (op == error_mark_node)
2449                   {
2450                     x = error_mark_node;
2451                     vec_free (nelts);
2452                     break;
2453                   }
2454                 if (nelts == NULL)
2455                   nelts = elts->copy ();
2456                 (*nelts)[i].value = op;
2457               }
2458           }
2459         if (nelts)
2460           x = build_constructor (TREE_TYPE (x), nelts);
2461         break;
2462       }
2463     case TREE_VEC:
2464       {
2465         bool changed = false;
2466         vec<tree, va_gc> *vec = make_tree_vector ();
2467         int i, n = TREE_VEC_LENGTH (x);
2468         vec_safe_reserve (vec, n);
2469
2470         for (i = 0; i < n; i++)
2471           {
2472             tree op = cp_fold (TREE_VEC_ELT (x, i));
2473             vec->quick_push (op);
2474             if (op != TREE_VEC_ELT (x, i))
2475               changed = true;
2476           }
2477
2478         if (changed)
2479           {
2480             r = copy_node (x);
2481             for (i = 0; i < n; i++)
2482               TREE_VEC_ELT (r, i) = (*vec)[i];
2483             x = r;
2484           }
2485
2486         release_tree_vector (vec);
2487       }
2488
2489       break;
2490
2491     case ARRAY_REF:
2492     case ARRAY_RANGE_REF:
2493
2494       loc = EXPR_LOCATION (x);
2495       op0 = cp_fold (TREE_OPERAND (x, 0));
2496       op1 = cp_fold (TREE_OPERAND (x, 1));
2497       op2 = cp_fold (TREE_OPERAND (x, 2));
2498       op3 = cp_fold (TREE_OPERAND (x, 3));
2499
2500       if (op0 != TREE_OPERAND (x, 0)
2501           || op1 != TREE_OPERAND (x, 1)
2502           || op2 != TREE_OPERAND (x, 2)
2503           || op3 != TREE_OPERAND (x, 3))
2504         {
2505           if (op0 == error_mark_node
2506               || op1 == error_mark_node
2507               || op2 == error_mark_node
2508               || op3 == error_mark_node)
2509             x = error_mark_node;
2510           else
2511             {
2512               x = build4_loc (loc, code, TREE_TYPE (x), op0, op1, op2, op3);
2513               TREE_READONLY (x) = TREE_READONLY (org_x);
2514               TREE_SIDE_EFFECTS (x) = TREE_SIDE_EFFECTS (org_x);
2515               TREE_THIS_VOLATILE (x) = TREE_THIS_VOLATILE (org_x);
2516             }
2517         }
2518
2519       x = fold (x);
2520       break;
2521
2522     case SAVE_EXPR:
2523       /* A SAVE_EXPR might contain e.g. (0 * i) + (0 * j), which, after
2524          folding, evaluates to an invariant.  In that case no need to wrap
2525          this folded tree with a SAVE_EXPR.  */
2526       r = cp_fold (TREE_OPERAND (x, 0));
2527       if (tree_invariant_p (r))
2528         x = r;
2529       break;
2530
2531     default:
2532       return org_x;
2533     }
2534
2535   fold_cache->put (org_x, x);
2536   /* Prevent that we try to fold an already folded result again.  */
2537   if (x != org_x)
2538     fold_cache->put (x, x);
2539
2540   return x;
2541 }
2542
2543 #include "gt-cp-cp-gimplify.h"