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 (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       genericize_omp_for_stmt (stmt_p, walk_subtrees, data);
1467       break;
1468
1469     case PTRMEM_CST:
1470       /* By the time we get here we're handing off to the back end, so we don't
1471          need or want to preserve PTRMEM_CST anymore.  */
1472       *stmt_p = cplus_expand_constant (stmt);
1473       *walk_subtrees = 0;
1474       break;
1475
1476     case MEM_REF:
1477       /* For MEM_REF, make sure not to sanitize the second operand even
1478          if it has reference type.  It is just an offset with a type
1479          holding other information.  There is no other processing we
1480          need to do for INTEGER_CSTs, so just ignore the second argument
1481          unconditionally.  */
1482       cp_walk_tree (&TREE_OPERAND (stmt, 0), cp_genericize_r, data, NULL);
1483       *walk_subtrees = 0;
1484       break;
1485
1486     case NOP_EXPR:
1487       if (!wtd->no_sanitize_p
1488           && sanitize_flags_p (SANITIZE_NULL | SANITIZE_ALIGNMENT)
1489           && TYPE_REF_P (TREE_TYPE (stmt)))
1490         ubsan_maybe_instrument_reference (stmt_p);
1491       break;
1492
1493     case CALL_EXPR:
1494       if (!wtd->no_sanitize_p
1495           && sanitize_flags_p ((SANITIZE_NULL
1496                                 | SANITIZE_ALIGNMENT | SANITIZE_VPTR)))
1497         {
1498           tree fn = CALL_EXPR_FN (stmt);
1499           if (fn != NULL_TREE
1500               && !error_operand_p (fn)
1501               && POINTER_TYPE_P (TREE_TYPE (fn))
1502               && TREE_CODE (TREE_TYPE (TREE_TYPE (fn))) == METHOD_TYPE)
1503             {
1504               bool is_ctor
1505                 = TREE_CODE (fn) == ADDR_EXPR
1506                   && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
1507                   && DECL_CONSTRUCTOR_P (TREE_OPERAND (fn, 0));
1508               if (sanitize_flags_p (SANITIZE_NULL | SANITIZE_ALIGNMENT))
1509                 ubsan_maybe_instrument_member_call (stmt, is_ctor);
1510               if (sanitize_flags_p (SANITIZE_VPTR) && !is_ctor)
1511                 cp_ubsan_maybe_instrument_member_call (stmt);
1512             }
1513           else if (fn == NULL_TREE
1514                    && CALL_EXPR_IFN (stmt) == IFN_UBSAN_NULL
1515                    && TREE_CODE (CALL_EXPR_ARG (stmt, 0)) == INTEGER_CST
1516                    && TYPE_REF_P (TREE_TYPE (CALL_EXPR_ARG (stmt, 0))))
1517             *walk_subtrees = 0;
1518         }
1519       /* Fall through.  */
1520     case AGGR_INIT_EXPR:
1521       /* For calls to a multi-versioned function, overload resolution
1522          returns the function with the highest target priority, that is,
1523          the version that will checked for dispatching first.  If this
1524          version is inlinable, a direct call to this version can be made
1525          otherwise the call should go through the dispatcher.  */
1526       {
1527         tree fn = cp_get_callee_fndecl_nofold (stmt);
1528         if (fn && DECL_FUNCTION_VERSIONED (fn)
1529             && (current_function_decl == NULL
1530                 || !targetm.target_option.can_inline_p (current_function_decl,
1531                                                         fn)))
1532           if (tree dis = get_function_version_dispatcher (fn))
1533             {
1534               mark_versions_used (dis);
1535               dis = build_address (dis);
1536               if (TREE_CODE (stmt) == CALL_EXPR)
1537                 CALL_EXPR_FN (stmt) = dis;
1538               else
1539                 AGGR_INIT_EXPR_FN (stmt) = dis;
1540             }
1541       }
1542       break;
1543
1544     case TARGET_EXPR:
1545       if (TARGET_EXPR_INITIAL (stmt)
1546           && TREE_CODE (TARGET_EXPR_INITIAL (stmt)) == CONSTRUCTOR
1547           && CONSTRUCTOR_PLACEHOLDER_BOUNDARY (TARGET_EXPR_INITIAL (stmt)))
1548         TARGET_EXPR_NO_ELIDE (stmt) = 1;
1549       break;
1550
1551     default:
1552       if (IS_TYPE_OR_DECL_P (stmt))
1553         *walk_subtrees = 0;
1554       break;
1555     }
1556
1557   p_set->add (*stmt_p);
1558
1559   return NULL;
1560 }
1561
1562 /* Lower C++ front end trees to GENERIC in T_P.  */
1563
1564 static void
1565 cp_genericize_tree (tree* t_p, bool handle_invisiref_parm_p)
1566 {
1567   struct cp_genericize_data wtd;
1568
1569   wtd.p_set = new hash_set<tree>;
1570   wtd.bind_expr_stack.create (0);
1571   wtd.omp_ctx = NULL;
1572   wtd.try_block = NULL_TREE;
1573   wtd.no_sanitize_p = false;
1574   wtd.handle_invisiref_parm_p = handle_invisiref_parm_p;
1575   cp_walk_tree (t_p, cp_genericize_r, &wtd, NULL);
1576   delete wtd.p_set;
1577   wtd.bind_expr_stack.release ();
1578   if (sanitize_flags_p (SANITIZE_VPTR))
1579     cp_ubsan_instrument_member_accesses (t_p);
1580 }
1581
1582 /* If a function that should end with a return in non-void
1583    function doesn't obviously end with return, add ubsan
1584    instrumentation code to verify it at runtime.  If -fsanitize=return
1585    is not enabled, instrument __builtin_unreachable.  */
1586
1587 static void
1588 cp_maybe_instrument_return (tree fndecl)
1589 {
1590   if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fndecl)))
1591       || DECL_CONSTRUCTOR_P (fndecl)
1592       || DECL_DESTRUCTOR_P (fndecl)
1593       || !targetm.warn_func_return (fndecl))
1594     return;
1595
1596   if (!sanitize_flags_p (SANITIZE_RETURN, fndecl)
1597       /* Don't add __builtin_unreachable () if not optimizing, it will not
1598          improve any optimizations in that case, just break UB code.
1599          Don't add it if -fsanitize=unreachable -fno-sanitize=return either,
1600          UBSan covers this with ubsan_instrument_return above where sufficient
1601          information is provided, while the __builtin_unreachable () below
1602          if return sanitization is disabled will just result in hard to
1603          understand runtime error without location.  */
1604       && (!optimize
1605           || sanitize_flags_p (SANITIZE_UNREACHABLE, fndecl)))
1606     return;
1607
1608   tree t = DECL_SAVED_TREE (fndecl);
1609   while (t)
1610     {
1611       switch (TREE_CODE (t))
1612         {
1613         case BIND_EXPR:
1614           t = BIND_EXPR_BODY (t);
1615           continue;
1616         case TRY_FINALLY_EXPR:
1617         case CLEANUP_POINT_EXPR:
1618           t = TREE_OPERAND (t, 0);
1619           continue;
1620         case STATEMENT_LIST:
1621           {
1622             tree_stmt_iterator i = tsi_last (t);
1623             if (!tsi_end_p (i))
1624               {
1625                 t = tsi_stmt (i);
1626                 continue;
1627               }
1628           }
1629           break;
1630         case RETURN_EXPR:
1631           return;
1632         default:
1633           break;
1634         }
1635       break;
1636     }
1637   if (t == NULL_TREE)
1638     return;
1639   tree *p = &DECL_SAVED_TREE (fndecl);
1640   if (TREE_CODE (*p) == BIND_EXPR)
1641     p = &BIND_EXPR_BODY (*p);
1642
1643   location_t loc = DECL_SOURCE_LOCATION (fndecl);
1644   if (sanitize_flags_p (SANITIZE_RETURN, fndecl))
1645     t = ubsan_instrument_return (loc);
1646   else
1647     {
1648       tree fndecl = builtin_decl_explicit (BUILT_IN_UNREACHABLE);
1649       t = build_call_expr_loc (BUILTINS_LOCATION, fndecl, 0);
1650     }
1651
1652   append_to_statement_list (t, p);
1653 }
1654
1655 void
1656 cp_genericize (tree fndecl)
1657 {
1658   tree t;
1659
1660   /* Fix up the types of parms passed by invisible reference.  */
1661   for (t = DECL_ARGUMENTS (fndecl); t; t = DECL_CHAIN (t))
1662     if (TREE_ADDRESSABLE (TREE_TYPE (t)))
1663       {
1664         /* If a function's arguments are copied to create a thunk,
1665            then DECL_BY_REFERENCE will be set -- but the type of the
1666            argument will be a pointer type, so we will never get
1667            here.  */
1668         gcc_assert (!DECL_BY_REFERENCE (t));
1669         gcc_assert (DECL_ARG_TYPE (t) != TREE_TYPE (t));
1670         TREE_TYPE (t) = DECL_ARG_TYPE (t);
1671         DECL_BY_REFERENCE (t) = 1;
1672         TREE_ADDRESSABLE (t) = 0;
1673         relayout_decl (t);
1674       }
1675
1676   /* Do the same for the return value.  */
1677   if (TREE_ADDRESSABLE (TREE_TYPE (DECL_RESULT (fndecl))))
1678     {
1679       t = DECL_RESULT (fndecl);
1680       TREE_TYPE (t) = build_reference_type (TREE_TYPE (t));
1681       DECL_BY_REFERENCE (t) = 1;
1682       TREE_ADDRESSABLE (t) = 0;
1683       relayout_decl (t);
1684       if (DECL_NAME (t))
1685         {
1686           /* Adjust DECL_VALUE_EXPR of the original var.  */
1687           tree outer = outer_curly_brace_block (current_function_decl);
1688           tree var;
1689
1690           if (outer)
1691             for (var = BLOCK_VARS (outer); var; var = DECL_CHAIN (var))
1692               if (VAR_P (var)
1693                   && DECL_NAME (t) == DECL_NAME (var)
1694                   && DECL_HAS_VALUE_EXPR_P (var)
1695                   && DECL_VALUE_EXPR (var) == t)
1696                 {
1697                   tree val = convert_from_reference (t);
1698                   SET_DECL_VALUE_EXPR (var, val);
1699                   break;
1700                 }
1701         }
1702     }
1703
1704   /* If we're a clone, the body is already GIMPLE.  */
1705   if (DECL_CLONED_FUNCTION_P (fndecl))
1706     return;
1707
1708   /* Allow cp_genericize calls to be nested.  */
1709   tree save_bc_label[2];
1710   save_bc_label[bc_break] = bc_label[bc_break];
1711   save_bc_label[bc_continue] = bc_label[bc_continue];
1712   bc_label[bc_break] = NULL_TREE;
1713   bc_label[bc_continue] = NULL_TREE;
1714
1715   /* We do want to see every occurrence of the parms, so we can't just use
1716      walk_tree's hash functionality.  */
1717   cp_genericize_tree (&DECL_SAVED_TREE (fndecl), true);
1718
1719   cp_maybe_instrument_return (fndecl);
1720
1721   /* Do everything else.  */
1722   c_genericize (fndecl);
1723
1724   gcc_assert (bc_label[bc_break] == NULL);
1725   gcc_assert (bc_label[bc_continue] == NULL);
1726   bc_label[bc_break] = save_bc_label[bc_break];
1727   bc_label[bc_continue] = save_bc_label[bc_continue];
1728 }
1729 \f
1730 /* Build code to apply FN to each member of ARG1 and ARG2.  FN may be
1731    NULL if there is in fact nothing to do.  ARG2 may be null if FN
1732    actually only takes one argument.  */
1733
1734 static tree
1735 cxx_omp_clause_apply_fn (tree fn, tree arg1, tree arg2)
1736 {
1737   tree defparm, parm, t;
1738   int i = 0;
1739   int nargs;
1740   tree *argarray;
1741
1742   if (fn == NULL)
1743     return NULL;
1744
1745   nargs = list_length (DECL_ARGUMENTS (fn));
1746   argarray = XALLOCAVEC (tree, nargs);
1747
1748   defparm = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fn)));
1749   if (arg2)
1750     defparm = TREE_CHAIN (defparm);
1751
1752   bool is_method = TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE;
1753   if (TREE_CODE (TREE_TYPE (arg1)) == ARRAY_TYPE)
1754     {
1755       tree inner_type = TREE_TYPE (arg1);
1756       tree start1, end1, p1;
1757       tree start2 = NULL, p2 = NULL;
1758       tree ret = NULL, lab;
1759
1760       start1 = arg1;
1761       start2 = arg2;
1762       do
1763         {
1764           inner_type = TREE_TYPE (inner_type);
1765           start1 = build4 (ARRAY_REF, inner_type, start1,
1766                            size_zero_node, NULL, NULL);
1767           if (arg2)
1768             start2 = build4 (ARRAY_REF, inner_type, start2,
1769                              size_zero_node, NULL, NULL);
1770         }
1771       while (TREE_CODE (inner_type) == ARRAY_TYPE);
1772       start1 = build_fold_addr_expr_loc (input_location, start1);
1773       if (arg2)
1774         start2 = build_fold_addr_expr_loc (input_location, start2);
1775
1776       end1 = TYPE_SIZE_UNIT (TREE_TYPE (arg1));
1777       end1 = fold_build_pointer_plus (start1, end1);
1778
1779       p1 = create_tmp_var (TREE_TYPE (start1));
1780       t = build2 (MODIFY_EXPR, TREE_TYPE (p1), p1, start1);
1781       append_to_statement_list (t, &ret);
1782
1783       if (arg2)
1784         {
1785           p2 = create_tmp_var (TREE_TYPE (start2));
1786           t = build2 (MODIFY_EXPR, TREE_TYPE (p2), p2, start2);
1787           append_to_statement_list (t, &ret);
1788         }
1789
1790       lab = create_artificial_label (input_location);
1791       t = build1 (LABEL_EXPR, void_type_node, lab);
1792       append_to_statement_list (t, &ret);
1793
1794       argarray[i++] = p1;
1795       if (arg2)
1796         argarray[i++] = p2;
1797       /* Handle default arguments.  */
1798       for (parm = defparm; parm && parm != void_list_node;
1799            parm = TREE_CHAIN (parm), i++)
1800         argarray[i] = convert_default_arg (TREE_VALUE (parm),
1801                                            TREE_PURPOSE (parm), fn,
1802                                            i - is_method, tf_warning_or_error);
1803       t = build_call_a (fn, i, argarray);
1804       t = fold_convert (void_type_node, t);
1805       t = fold_build_cleanup_point_expr (TREE_TYPE (t), t);
1806       append_to_statement_list (t, &ret);
1807
1808       t = fold_build_pointer_plus (p1, TYPE_SIZE_UNIT (inner_type));
1809       t = build2 (MODIFY_EXPR, TREE_TYPE (p1), p1, t);
1810       append_to_statement_list (t, &ret);
1811
1812       if (arg2)
1813         {
1814           t = fold_build_pointer_plus (p2, TYPE_SIZE_UNIT (inner_type));
1815           t = build2 (MODIFY_EXPR, TREE_TYPE (p2), p2, t);
1816           append_to_statement_list (t, &ret);
1817         }
1818
1819       t = build2 (NE_EXPR, boolean_type_node, p1, end1);
1820       t = build3 (COND_EXPR, void_type_node, t, build_and_jump (&lab), NULL);
1821       append_to_statement_list (t, &ret);
1822
1823       return ret;
1824     }
1825   else
1826     {
1827       argarray[i++] = build_fold_addr_expr_loc (input_location, arg1);
1828       if (arg2)
1829         argarray[i++] = build_fold_addr_expr_loc (input_location, arg2);
1830       /* Handle default arguments.  */
1831       for (parm = defparm; parm && parm != void_list_node;
1832            parm = TREE_CHAIN (parm), i++)
1833         argarray[i] = convert_default_arg (TREE_VALUE (parm),
1834                                            TREE_PURPOSE (parm), fn,
1835                                            i - is_method, tf_warning_or_error);
1836       t = build_call_a (fn, i, argarray);
1837       t = fold_convert (void_type_node, t);
1838       return fold_build_cleanup_point_expr (TREE_TYPE (t), t);
1839     }
1840 }
1841
1842 /* Return code to initialize DECL with its default constructor, or
1843    NULL if there's nothing to do.  */
1844
1845 tree
1846 cxx_omp_clause_default_ctor (tree clause, tree decl, tree /*outer*/)
1847 {
1848   tree info = CP_OMP_CLAUSE_INFO (clause);
1849   tree ret = NULL;
1850
1851   if (info)
1852     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 0), decl, NULL);
1853
1854   return ret;
1855 }
1856
1857 /* Return code to initialize DST with a copy constructor from SRC.  */
1858
1859 tree
1860 cxx_omp_clause_copy_ctor (tree clause, tree dst, tree src)
1861 {
1862   tree info = CP_OMP_CLAUSE_INFO (clause);
1863   tree ret = NULL;
1864
1865   if (info)
1866     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 0), dst, src);
1867   if (ret == NULL)
1868     ret = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
1869
1870   return ret;
1871 }
1872
1873 /* Similarly, except use an assignment operator instead.  */
1874
1875 tree
1876 cxx_omp_clause_assign_op (tree clause, tree dst, tree src)
1877 {
1878   tree info = CP_OMP_CLAUSE_INFO (clause);
1879   tree ret = NULL;
1880
1881   if (info)
1882     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 2), dst, src);
1883   if (ret == NULL)
1884     ret = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
1885
1886   return ret;
1887 }
1888
1889 /* Return code to destroy DECL.  */
1890
1891 tree
1892 cxx_omp_clause_dtor (tree clause, tree decl)
1893 {
1894   tree info = CP_OMP_CLAUSE_INFO (clause);
1895   tree ret = NULL;
1896
1897   if (info)
1898     ret = cxx_omp_clause_apply_fn (TREE_VEC_ELT (info, 1), decl, NULL);
1899
1900   return ret;
1901 }
1902
1903 /* True if OpenMP should privatize what this DECL points to rather
1904    than the DECL itself.  */
1905
1906 bool
1907 cxx_omp_privatize_by_reference (const_tree decl)
1908 {
1909   return (TYPE_REF_P (TREE_TYPE (decl))
1910           || is_invisiref_parm (decl));
1911 }
1912
1913 /* Return true if DECL is const qualified var having no mutable member.  */
1914 bool
1915 cxx_omp_const_qual_no_mutable (tree decl)
1916 {
1917   tree type = TREE_TYPE (decl);
1918   if (TYPE_REF_P (type))
1919     {
1920       if (!is_invisiref_parm (decl))
1921         return false;
1922       type = TREE_TYPE (type);
1923
1924       if (TREE_CODE (decl) == RESULT_DECL && DECL_NAME (decl))
1925         {
1926           /* NVR doesn't preserve const qualification of the
1927              variable's type.  */
1928           tree outer = outer_curly_brace_block (current_function_decl);
1929           tree var;
1930
1931           if (outer)
1932             for (var = BLOCK_VARS (outer); var; var = DECL_CHAIN (var))
1933               if (VAR_P (var)
1934                   && DECL_NAME (decl) == DECL_NAME (var)
1935                   && (TYPE_MAIN_VARIANT (type)
1936                       == TYPE_MAIN_VARIANT (TREE_TYPE (var))))
1937                 {
1938                   if (TYPE_READONLY (TREE_TYPE (var)))
1939                     type = TREE_TYPE (var);
1940                   break;
1941                 }
1942         }
1943     }
1944
1945   if (type == error_mark_node)
1946     return false;
1947
1948   /* Variables with const-qualified type having no mutable member
1949      are predetermined shared.  */
1950   if (TYPE_READONLY (type) && !cp_has_mutable_p (type))
1951     return true;
1952
1953   return false;
1954 }
1955
1956 /* True if OpenMP sharing attribute of DECL is predetermined.  */
1957
1958 enum omp_clause_default_kind
1959 cxx_omp_predetermined_sharing_1 (tree decl)
1960 {
1961   /* Static data members are predetermined shared.  */
1962   if (TREE_STATIC (decl))
1963     {
1964       tree ctx = CP_DECL_CONTEXT (decl);
1965       if (TYPE_P (ctx) && MAYBE_CLASS_TYPE_P (ctx))
1966         return OMP_CLAUSE_DEFAULT_SHARED;
1967     }
1968
1969   /* Const qualified vars having no mutable member are predetermined
1970      shared.  */
1971   if (cxx_omp_const_qual_no_mutable (decl))
1972     return OMP_CLAUSE_DEFAULT_SHARED;
1973
1974   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
1975 }
1976
1977 /* Likewise, but also include the artificial vars.  We don't want to
1978    disallow the artificial vars being mentioned in explicit clauses,
1979    as we use artificial vars e.g. for loop constructs with random
1980    access iterators other than pointers, but during gimplification
1981    we want to treat them as predetermined.  */
1982
1983 enum omp_clause_default_kind
1984 cxx_omp_predetermined_sharing (tree decl)
1985 {
1986   enum omp_clause_default_kind ret = cxx_omp_predetermined_sharing_1 (decl);
1987   if (ret != OMP_CLAUSE_DEFAULT_UNSPECIFIED)
1988     return ret;
1989
1990   /* Predetermine artificial variables holding integral values, those
1991      are usually result of gimplify_one_sizepos or SAVE_EXPR
1992      gimplification.  */
1993   if (VAR_P (decl)
1994       && DECL_ARTIFICIAL (decl)
1995       && INTEGRAL_TYPE_P (TREE_TYPE (decl))
1996       && !(DECL_LANG_SPECIFIC (decl)
1997            && DECL_OMP_PRIVATIZED_MEMBER (decl)))
1998     return OMP_CLAUSE_DEFAULT_SHARED;
1999
2000   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
2001 }
2002
2003 /* Finalize an implicitly determined clause.  */
2004
2005 void
2006 cxx_omp_finish_clause (tree c, gimple_seq *)
2007 {
2008   tree decl, inner_type;
2009   bool make_shared = false;
2010
2011   if (OMP_CLAUSE_CODE (c) != OMP_CLAUSE_FIRSTPRIVATE)
2012     return;
2013
2014   decl = OMP_CLAUSE_DECL (c);
2015   decl = require_complete_type (decl);
2016   inner_type = TREE_TYPE (decl);
2017   if (decl == error_mark_node)
2018     make_shared = true;
2019   else if (TYPE_REF_P (TREE_TYPE (decl)))
2020     inner_type = TREE_TYPE (inner_type);
2021
2022   /* We're interested in the base element, not arrays.  */
2023   while (TREE_CODE (inner_type) == ARRAY_TYPE)
2024     inner_type = TREE_TYPE (inner_type);
2025
2026   /* Check for special function availability by building a call to one.
2027      Save the results, because later we won't be in the right context
2028      for making these queries.  */
2029   if (!make_shared
2030       && CLASS_TYPE_P (inner_type)
2031       && cxx_omp_create_clause_info (c, inner_type, false, true, false, true))
2032     make_shared = true;
2033
2034   if (make_shared)
2035     {
2036       OMP_CLAUSE_CODE (c) = OMP_CLAUSE_SHARED;
2037       OMP_CLAUSE_SHARED_FIRSTPRIVATE (c) = 0;
2038       OMP_CLAUSE_SHARED_READONLY (c) = 0;
2039     }
2040 }
2041
2042 /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
2043    disregarded in OpenMP construct, because it is going to be
2044    remapped during OpenMP lowering.  SHARED is true if DECL
2045    is going to be shared, false if it is going to be privatized.  */
2046
2047 bool
2048 cxx_omp_disregard_value_expr (tree decl, bool shared)
2049 {
2050   return !shared
2051          && VAR_P (decl)
2052          && DECL_HAS_VALUE_EXPR_P (decl)
2053          && DECL_ARTIFICIAL (decl)
2054          && DECL_LANG_SPECIFIC (decl)
2055          && DECL_OMP_PRIVATIZED_MEMBER (decl);
2056 }
2057
2058 /* Fold expression X which is used as an rvalue if RVAL is true.  */
2059
2060 static tree
2061 cp_fold_maybe_rvalue (tree x, bool rval)
2062 {
2063   while (true)
2064     {
2065       x = cp_fold (x);
2066       if (rval && DECL_P (x)
2067           && !TYPE_REF_P (TREE_TYPE (x)))
2068         {
2069           tree v = decl_constant_value (x);
2070           if (v != x && v != error_mark_node)
2071             {
2072               x = v;
2073               continue;
2074             }
2075         }
2076       break;
2077     }
2078   return x;
2079 }
2080
2081 /* Fold expression X which is used as an rvalue.  */
2082
2083 static tree
2084 cp_fold_rvalue (tree x)
2085 {
2086   return cp_fold_maybe_rvalue (x, true);
2087 }
2088
2089 /* Perform folding on expression X.  */
2090
2091 tree
2092 cp_fully_fold (tree x)
2093 {
2094   if (processing_template_decl)
2095     return x;
2096   /* FIXME cp_fold ought to be a superset of maybe_constant_value so we don't
2097      have to call both.  */
2098   if (cxx_dialect >= cxx11)
2099     {
2100       x = maybe_constant_value (x);
2101       /* Sometimes we are given a CONSTRUCTOR but the call above wraps it into
2102          a TARGET_EXPR; undo that here.  */
2103       if (TREE_CODE (x) == TARGET_EXPR)
2104         x = TARGET_EXPR_INITIAL (x);
2105       else if (TREE_CODE (x) == VIEW_CONVERT_EXPR
2106                && TREE_CODE (TREE_OPERAND (x, 0)) == CONSTRUCTOR
2107                && TREE_TYPE (TREE_OPERAND (x, 0)) == TREE_TYPE (x))
2108         x = TREE_OPERAND (x, 0);
2109     }
2110   return cp_fold_rvalue (x);
2111 }
2112
2113 /* c-common interface to cp_fold.  If IN_INIT, this is in a static initializer
2114    and certain changes are made to the folding done.  Or should be (FIXME).  We
2115    never touch maybe_const, as it is only used for the C front-end
2116    C_MAYBE_CONST_EXPR.  */
2117
2118 tree
2119 c_fully_fold (tree x, bool /*in_init*/, bool */*maybe_const*/, bool lval)
2120 {
2121   return cp_fold_maybe_rvalue (x, !lval);
2122 }
2123
2124 static GTY((deletable)) hash_map<tree, tree> *fold_cache;
2125
2126 /* Dispose of the whole FOLD_CACHE.  */
2127
2128 void
2129 clear_fold_cache (void)
2130 {
2131   if (fold_cache != NULL)
2132     fold_cache->empty ();
2133 }
2134
2135 /*  This function tries to fold an expression X.
2136     To avoid combinatorial explosion, folding results are kept in fold_cache.
2137     If X is invalid, we don't fold at all.
2138     For performance reasons we don't cache expressions representing a
2139     declaration or constant.
2140     Function returns X or its folded variant.  */
2141
2142 static tree
2143 cp_fold (tree x)
2144 {
2145   tree op0, op1, op2, op3;
2146   tree org_x = x, r = NULL_TREE;
2147   enum tree_code code;
2148   location_t loc;
2149   bool rval_ops = true;
2150
2151   if (!x || x == error_mark_node)
2152     return x;
2153
2154   if (EXPR_P (x) && (!TREE_TYPE (x) || TREE_TYPE (x) == error_mark_node))
2155     return x;
2156
2157   /* Don't bother to cache DECLs or constants.  */
2158   if (DECL_P (x) || CONSTANT_CLASS_P (x))
2159     return x;
2160
2161   if (fold_cache == NULL)
2162     fold_cache = hash_map<tree, tree>::create_ggc (101);
2163
2164   if (tree *cached = fold_cache->get (x))
2165     return *cached;
2166
2167   code = TREE_CODE (x);
2168   switch (code)
2169     {
2170     case CLEANUP_POINT_EXPR:
2171       /* Strip CLEANUP_POINT_EXPR if the expression doesn't have side
2172          effects.  */
2173       r = cp_fold_rvalue (TREE_OPERAND (x, 0));
2174       if (!TREE_SIDE_EFFECTS (r))
2175         x = r;
2176       break;
2177
2178     case SIZEOF_EXPR:
2179       x = fold_sizeof_expr (x);
2180       break;
2181
2182     case VIEW_CONVERT_EXPR:
2183       rval_ops = false;
2184       /* FALLTHRU */
2185     case CONVERT_EXPR:
2186     case NOP_EXPR:
2187     case NON_LVALUE_EXPR:
2188
2189       if (VOID_TYPE_P (TREE_TYPE (x)))
2190         {
2191           /* This is just to make sure we don't end up with casts to
2192              void from error_mark_node.  If we just return x, then
2193              cp_fold_r might fold the operand into error_mark_node and
2194              leave the conversion in the IR.  STRIP_USELESS_TYPE_CONVERSION
2195              during gimplification doesn't like such casts.
2196              Don't create a new tree if op0 != TREE_OPERAND (x, 0), the
2197              folding of the operand should be in the caches and if in cp_fold_r
2198              it will modify it in place.  */
2199           op0 = cp_fold (TREE_OPERAND (x, 0));
2200           if (op0 == error_mark_node)
2201             x = error_mark_node;
2202           break;
2203         }
2204
2205       loc = EXPR_LOCATION (x);
2206       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), rval_ops);
2207
2208       if (code == CONVERT_EXPR
2209           && SCALAR_TYPE_P (TREE_TYPE (x))
2210           && op0 != void_node)
2211         /* During parsing we used convert_to_*_nofold; re-convert now using the
2212            folding variants, since fold() doesn't do those transformations.  */
2213         x = fold (convert (TREE_TYPE (x), op0));
2214       else if (op0 != TREE_OPERAND (x, 0))
2215         {
2216           if (op0 == error_mark_node)
2217             x = error_mark_node;
2218           else
2219             x = fold_build1_loc (loc, code, TREE_TYPE (x), op0);
2220         }
2221       else
2222         x = fold (x);
2223
2224       /* Conversion of an out-of-range value has implementation-defined
2225          behavior; the language considers it different from arithmetic
2226          overflow, which is undefined.  */
2227       if (TREE_CODE (op0) == INTEGER_CST
2228           && TREE_OVERFLOW_P (x) && !TREE_OVERFLOW_P (op0))
2229         TREE_OVERFLOW (x) = false;
2230
2231       break;
2232
2233     case INDIRECT_REF:
2234       /* We don't need the decltype(auto) obfuscation anymore.  */
2235       if (REF_PARENTHESIZED_P (x))
2236         {
2237           tree p = maybe_undo_parenthesized_ref (x);
2238           return cp_fold (p);
2239         }
2240       goto unary;
2241
2242     case ADDR_EXPR:
2243       loc = EXPR_LOCATION (x);
2244       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), false);
2245
2246       /* Cope with user tricks that amount to offsetof.  */
2247       if (op0 != error_mark_node
2248           && TREE_CODE (TREE_TYPE (op0)) != FUNCTION_TYPE
2249           && TREE_CODE (TREE_TYPE (op0)) != METHOD_TYPE)
2250         {
2251           tree val = get_base_address (op0);
2252           if (val
2253               && INDIRECT_REF_P (val)
2254               && COMPLETE_TYPE_P (TREE_TYPE (val))
2255               && TREE_CONSTANT (TREE_OPERAND (val, 0)))
2256             {
2257               val = TREE_OPERAND (val, 0);
2258               STRIP_NOPS (val);
2259               if (TREE_CODE (val) == INTEGER_CST)
2260                 return fold_offsetof (op0, TREE_TYPE (x));
2261             }
2262         }
2263       goto finish_unary;
2264
2265     case REALPART_EXPR:
2266     case IMAGPART_EXPR:
2267       rval_ops = false;
2268       /* FALLTHRU */
2269     case CONJ_EXPR:
2270     case FIX_TRUNC_EXPR:
2271     case FLOAT_EXPR:
2272     case NEGATE_EXPR:
2273     case ABS_EXPR:
2274     case BIT_NOT_EXPR:
2275     case TRUTH_NOT_EXPR:
2276     case FIXED_CONVERT_EXPR:
2277     unary:
2278
2279       loc = EXPR_LOCATION (x);
2280       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), rval_ops);
2281
2282     finish_unary:
2283       if (op0 != TREE_OPERAND (x, 0))
2284         {
2285           if (op0 == error_mark_node)
2286             x = error_mark_node;
2287           else
2288             {
2289               x = fold_build1_loc (loc, code, TREE_TYPE (x), op0);
2290               if (code == INDIRECT_REF
2291                   && (INDIRECT_REF_P (x) || TREE_CODE (x) == MEM_REF))
2292                 {
2293                   TREE_READONLY (x) = TREE_READONLY (org_x);
2294                   TREE_SIDE_EFFECTS (x) = TREE_SIDE_EFFECTS (org_x);
2295                   TREE_THIS_VOLATILE (x) = TREE_THIS_VOLATILE (org_x);
2296                 }
2297             }
2298         }
2299       else
2300         x = fold (x);
2301
2302       gcc_assert (TREE_CODE (x) != COND_EXPR
2303                   || !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (x, 0))));
2304       break;
2305
2306     case UNARY_PLUS_EXPR:
2307       op0 = cp_fold_rvalue (TREE_OPERAND (x, 0));
2308       if (op0 == error_mark_node)
2309         x = error_mark_node;
2310       else
2311         x = fold_convert (TREE_TYPE (x), op0);
2312       break;
2313
2314     case POSTDECREMENT_EXPR:
2315     case POSTINCREMENT_EXPR:
2316     case INIT_EXPR:
2317     case PREDECREMENT_EXPR:
2318     case PREINCREMENT_EXPR:
2319     case COMPOUND_EXPR:
2320     case MODIFY_EXPR:
2321       rval_ops = false;
2322       /* FALLTHRU */
2323     case POINTER_PLUS_EXPR:
2324     case PLUS_EXPR:
2325     case POINTER_DIFF_EXPR:
2326     case MINUS_EXPR:
2327     case MULT_EXPR:
2328     case TRUNC_DIV_EXPR:
2329     case CEIL_DIV_EXPR:
2330     case FLOOR_DIV_EXPR:
2331     case ROUND_DIV_EXPR:
2332     case TRUNC_MOD_EXPR:
2333     case CEIL_MOD_EXPR:
2334     case ROUND_MOD_EXPR:
2335     case RDIV_EXPR:
2336     case EXACT_DIV_EXPR:
2337     case MIN_EXPR:
2338     case MAX_EXPR:
2339     case LSHIFT_EXPR:
2340     case RSHIFT_EXPR:
2341     case LROTATE_EXPR:
2342     case RROTATE_EXPR:
2343     case BIT_AND_EXPR:
2344     case BIT_IOR_EXPR:
2345     case BIT_XOR_EXPR:
2346     case TRUTH_AND_EXPR:
2347     case TRUTH_ANDIF_EXPR:
2348     case TRUTH_OR_EXPR:
2349     case TRUTH_ORIF_EXPR:
2350     case TRUTH_XOR_EXPR:
2351     case LT_EXPR: case LE_EXPR:
2352     case GT_EXPR: case GE_EXPR:
2353     case EQ_EXPR: case NE_EXPR:
2354     case UNORDERED_EXPR: case ORDERED_EXPR:
2355     case UNLT_EXPR: case UNLE_EXPR:
2356     case UNGT_EXPR: case UNGE_EXPR:
2357     case UNEQ_EXPR: case LTGT_EXPR:
2358     case RANGE_EXPR: case COMPLEX_EXPR:
2359
2360       loc = EXPR_LOCATION (x);
2361       op0 = cp_fold_maybe_rvalue (TREE_OPERAND (x, 0), rval_ops);
2362       op1 = cp_fold_rvalue (TREE_OPERAND (x, 1));
2363
2364       if (op0 != TREE_OPERAND (x, 0) || op1 != TREE_OPERAND (x, 1))
2365         {
2366           if (op0 == error_mark_node || op1 == error_mark_node)
2367             x = error_mark_node;
2368           else
2369             x = fold_build2_loc (loc, code, TREE_TYPE (x), op0, op1);
2370         }
2371       else
2372         x = fold (x);
2373
2374       if (TREE_NO_WARNING (org_x)
2375           && warn_nonnull_compare
2376           && COMPARISON_CLASS_P (org_x))
2377         {
2378           if (x == error_mark_node || TREE_CODE (x) == INTEGER_CST)
2379             ;
2380           else if (COMPARISON_CLASS_P (x))
2381             TREE_NO_WARNING (x) = 1;
2382           /* Otherwise give up on optimizing these, let GIMPLE folders
2383              optimize those later on.  */
2384           else if (op0 != TREE_OPERAND (org_x, 0)
2385                    || op1 != TREE_OPERAND (org_x, 1))
2386             {
2387               x = build2_loc (loc, code, TREE_TYPE (org_x), op0, op1);
2388               TREE_NO_WARNING (x) = 1;
2389             }
2390           else
2391             x = org_x;
2392         }
2393       break;
2394
2395     case VEC_COND_EXPR:
2396     case COND_EXPR:
2397       loc = EXPR_LOCATION (x);
2398       op0 = cp_fold_rvalue (TREE_OPERAND (x, 0));
2399       op1 = cp_fold (TREE_OPERAND (x, 1));
2400       op2 = cp_fold (TREE_OPERAND (x, 2));
2401
2402       if (TREE_CODE (TREE_TYPE (x)) == BOOLEAN_TYPE)
2403         {
2404           warning_sentinel s (warn_int_in_bool_context);
2405           if (!VOID_TYPE_P (TREE_TYPE (op1)))
2406             op1 = cp_truthvalue_conversion (op1);
2407           if (!VOID_TYPE_P (TREE_TYPE (op2)))
2408             op2 = cp_truthvalue_conversion (op2);
2409         }
2410       else if (VOID_TYPE_P (TREE_TYPE (x)))
2411         {
2412           if (TREE_CODE (op0) == INTEGER_CST)
2413             {
2414               /* If the condition is constant, fold can fold away
2415                  the COND_EXPR.  If some statement-level uses of COND_EXPR
2416                  have one of the branches NULL, avoid folding crash.  */
2417               if (!op1)
2418                 op1 = build_empty_stmt (loc);
2419               if (!op2)
2420                 op2 = build_empty_stmt (loc);
2421             }
2422           else
2423             {
2424               /* Otherwise, don't bother folding a void condition, since
2425                  it can't produce a constant value.  */
2426               if (op0 != TREE_OPERAND (x, 0)
2427                   || op1 != TREE_OPERAND (x, 1)
2428                   || op2 != TREE_OPERAND (x, 2))
2429                 x = build3_loc (loc, code, TREE_TYPE (x), op0, op1, op2);
2430               break;
2431             }
2432         }
2433
2434       if (op0 != TREE_OPERAND (x, 0)
2435           || op1 != TREE_OPERAND (x, 1)
2436           || op2 != TREE_OPERAND (x, 2))
2437         {
2438           if (op0 == error_mark_node
2439               || op1 == error_mark_node
2440               || op2 == error_mark_node)
2441             x = error_mark_node;
2442           else
2443             x = fold_build3_loc (loc, code, TREE_TYPE (x), op0, op1, op2);
2444         }
2445       else
2446         x = fold (x);
2447
2448       /* A COND_EXPR might have incompatible types in branches if one or both
2449          arms are bitfields.  If folding exposed such a branch, fix it up.  */
2450       if (TREE_CODE (x) != code
2451           && x != error_mark_node
2452           && !useless_type_conversion_p (TREE_TYPE (org_x), TREE_TYPE (x)))
2453         x = fold_convert (TREE_TYPE (org_x), x);
2454
2455       break;
2456
2457     case CALL_EXPR:
2458       {
2459         int i, m, sv = optimize, nw = sv, changed = 0;
2460         tree callee = get_callee_fndecl (x);
2461
2462         /* Some built-in function calls will be evaluated at compile-time in
2463            fold ().  Set optimize to 1 when folding __builtin_constant_p inside
2464            a constexpr function so that fold_builtin_1 doesn't fold it to 0.  */
2465         if (callee && DECL_BUILT_IN (callee) && !optimize
2466             && DECL_IS_BUILTIN_CONSTANT_P (callee)
2467             && current_function_decl
2468             && DECL_DECLARED_CONSTEXPR_P (current_function_decl))
2469           nw = 1;
2470
2471         x = copy_node (x);
2472
2473         m = call_expr_nargs (x);
2474         for (i = 0; i < m; i++)
2475           {
2476             r = cp_fold (CALL_EXPR_ARG (x, i));
2477             if (r != CALL_EXPR_ARG (x, i))
2478               {
2479                 if (r == error_mark_node)
2480                   {
2481                     x = error_mark_node;
2482                     break;
2483                   }
2484                 changed = 1;
2485               }
2486             CALL_EXPR_ARG (x, i) = r;
2487           }
2488         if (x == error_mark_node)
2489           break;
2490
2491         optimize = nw;
2492         r = fold (x);
2493         optimize = sv;
2494
2495         if (TREE_CODE (r) != CALL_EXPR)
2496           {
2497             x = cp_fold (r);
2498             break;
2499           }
2500
2501         optimize = nw;
2502
2503         /* Invoke maybe_constant_value for functions declared
2504            constexpr and not called with AGGR_INIT_EXPRs.
2505            TODO:
2506            Do constexpr expansion of expressions where the call itself is not
2507            constant, but the call followed by an INDIRECT_REF is.  */
2508         if (callee && DECL_DECLARED_CONSTEXPR_P (callee)
2509             && !flag_no_inline)
2510           r = maybe_constant_value (x);
2511         optimize = sv;
2512
2513         if (TREE_CODE (r) != CALL_EXPR)
2514           {
2515             if (DECL_CONSTRUCTOR_P (callee))
2516               {
2517                 loc = EXPR_LOCATION (x);
2518                 tree s = build_fold_indirect_ref_loc (loc,
2519                                                       CALL_EXPR_ARG (x, 0));
2520                 r = build2_loc (loc, INIT_EXPR, TREE_TYPE (s), s, r);
2521               }
2522             x = r;
2523             break;
2524           }
2525
2526         if (!changed)
2527           x = org_x;
2528         break;
2529       }
2530
2531     case CONSTRUCTOR:
2532       {
2533         unsigned i;
2534         constructor_elt *p;
2535         vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (x);
2536         vec<constructor_elt, va_gc> *nelts = NULL;
2537         FOR_EACH_VEC_SAFE_ELT (elts, i, p)
2538           {
2539             tree op = cp_fold (p->value);
2540             if (op != p->value)
2541               {
2542                 if (op == error_mark_node)
2543                   {
2544                     x = error_mark_node;
2545                     vec_free (nelts);
2546                     break;
2547                   }
2548                 if (nelts == NULL)
2549                   nelts = elts->copy ();
2550                 (*nelts)[i].value = op;
2551               }
2552           }
2553         if (nelts)
2554           {
2555             x = build_constructor (TREE_TYPE (x), nelts);
2556             CONSTRUCTOR_PLACEHOLDER_BOUNDARY (x)
2557               = CONSTRUCTOR_PLACEHOLDER_BOUNDARY (org_x);
2558           }
2559         if (VECTOR_TYPE_P (TREE_TYPE (x)))
2560           x = fold (x);
2561         break;
2562       }
2563     case TREE_VEC:
2564       {
2565         bool changed = false;
2566         vec<tree, va_gc> *vec = make_tree_vector ();
2567         int i, n = TREE_VEC_LENGTH (x);
2568         vec_safe_reserve (vec, n);
2569
2570         for (i = 0; i < n; i++)
2571           {
2572             tree op = cp_fold (TREE_VEC_ELT (x, i));
2573             vec->quick_push (op);
2574             if (op != TREE_VEC_ELT (x, i))
2575               changed = true;
2576           }
2577
2578         if (changed)
2579           {
2580             r = copy_node (x);
2581             for (i = 0; i < n; i++)
2582               TREE_VEC_ELT (r, i) = (*vec)[i];
2583             x = r;
2584           }
2585
2586         release_tree_vector (vec);
2587       }
2588
2589       break;
2590
2591     case ARRAY_REF:
2592     case ARRAY_RANGE_REF:
2593
2594       loc = EXPR_LOCATION (x);
2595       op0 = cp_fold (TREE_OPERAND (x, 0));
2596       op1 = cp_fold (TREE_OPERAND (x, 1));
2597       op2 = cp_fold (TREE_OPERAND (x, 2));
2598       op3 = cp_fold (TREE_OPERAND (x, 3));
2599
2600       if (op0 != TREE_OPERAND (x, 0)
2601           || op1 != TREE_OPERAND (x, 1)
2602           || op2 != TREE_OPERAND (x, 2)
2603           || op3 != TREE_OPERAND (x, 3))
2604         {
2605           if (op0 == error_mark_node
2606               || op1 == error_mark_node
2607               || op2 == error_mark_node
2608               || op3 == error_mark_node)
2609             x = error_mark_node;
2610           else
2611             {
2612               x = build4_loc (loc, code, TREE_TYPE (x), op0, op1, op2, op3);
2613               TREE_READONLY (x) = TREE_READONLY (org_x);
2614               TREE_SIDE_EFFECTS (x) = TREE_SIDE_EFFECTS (org_x);
2615               TREE_THIS_VOLATILE (x) = TREE_THIS_VOLATILE (org_x);
2616             }
2617         }
2618
2619       x = fold (x);
2620       break;
2621
2622     case SAVE_EXPR:
2623       /* A SAVE_EXPR might contain e.g. (0 * i) + (0 * j), which, after
2624          folding, evaluates to an invariant.  In that case no need to wrap
2625          this folded tree with a SAVE_EXPR.  */
2626       r = cp_fold (TREE_OPERAND (x, 0));
2627       if (tree_invariant_p (r))
2628         x = r;
2629       break;
2630
2631     default:
2632       return org_x;
2633     }
2634
2635   fold_cache->put (org_x, x);
2636   /* Prevent that we try to fold an already folded result again.  */
2637   if (x != org_x)
2638     fold_cache->put (x, x);
2639
2640   return x;
2641 }
2642
2643 #include "gt-cp-cp-gimplify.h"