gcc-4_6_3-mobile/gcc/gimple-fold.c

   1 /* Statement simplification on GIMPLE.
   2    Copyright (C) 2010, 2011 Free Software Foundation, Inc.
   3    Split out from tree-ssa-ccp.c.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it
   8 under the terms of the GNU General Public License as published by the
   9 Free Software Foundation; either version 3, or (at your option) any
  10 later version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT
  13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "tree.h"
  26 #include "flags.h"
  27 #include "function.h"
  28 #include "tree-dump.h"
  29 #include "tree-flow.h"
  30 #include "tree-pass.h"
  31 #include "tree-ssa-propagate.h"
  32 #include "target.h"
  33
  34 /* Return true when DECL can be referenced from current unit.
  35    We can get declarations that are not possible to reference for
  36    various reasons:
  37
  38      1) When analyzing C++ virtual tables.
  39         C++ virtual tables do have known constructors even
  40         when they are keyed to other compilation unit.
  41         Those tables can contain pointers to methods and vars
  42         in other units.  Those methods have both STATIC and EXTERNAL
  43         set.
  44      2) In WHOPR mode devirtualization might lead to reference
  45         to method that was partitioned elsehwere.
  46         In this case we have static VAR_DECL or FUNCTION_DECL
  47         that has no corresponding callgraph/varpool node
  48         declaring the body.
  49      3) COMDAT functions referred by external vtables that
  50         we devirtualize only during final copmilation stage.
  51         At this time we already decided that we will not output
  52         the function body and thus we can't reference the symbol
  53         directly.  */
  54
  55 static bool
  56 can_refer_decl_in_current_unit_p (tree decl)
  57 {
  58   struct varpool_node *vnode;
  59   struct cgraph_node *node;
  60
  61   if (!TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
  62     return true;
  63   /* External flag is set, so we deal with C++ reference
  64      to static object from other file.  */
  65   if (DECL_EXTERNAL (decl) && TREE_STATIC (decl)
  66       && TREE_CODE (decl) == VAR_DECL)
  67     {
  68       /* Just be sure it is not big in frontend setting
  69          flags incorrectly.  Those variables should never
  70          be finalized.  */
  71       gcc_checking_assert (!(vnode = varpool_get_node (decl))
  72                            || !vnode->finalized);
  73       return false;
  74     }
  75   /* When function is public, we always can introduce new reference.
  76      Exception are the COMDAT functions where introducing a direct
  77      reference imply need to include function body in the curren tunit.  */
  78   if (TREE_PUBLIC (decl) && !DECL_COMDAT (decl))
  79     return true;
  80   /* We are not at ltrans stage; so don't worry about WHOPR.
  81      Also when still gimplifying all referred comdat functions will be
  82      produced.  */
  83   if (!flag_ltrans && (!DECL_COMDAT (decl) || !cgraph_function_flags_ready))
  84     return true;
  85   /* If we already output the function body, we are safe.  */
  86   if (TREE_ASM_WRITTEN (decl))
  87     return true;
  88   if (TREE_CODE (decl) == FUNCTION_DECL)
  89     {
  90       node = cgraph_get_node (decl);
  91       /* Check that we still have function body and that we didn't took
  92          the decision to eliminate offline copy of the function yet.
  93          The second is important when devirtualization happens during final
  94          compilation stage when making a new reference no longer makes callee
  95          to be compiled.  */
  96       if (!node || !node->analyzed || node->global.inlined_to)
  97         return false;
  98     }
  99   else if (TREE_CODE (decl) == VAR_DECL)
 100     {
 101       vnode = varpool_get_node (decl);
 102       if (!vnode || !vnode->finalized)
 103         return false;
 104     }
 105   return true;
 106 }
 107
 108 /* CVAL is value taken from DECL_INITIAL of variable.  Try to transorm it into
 109    acceptable form for is_gimple_min_invariant.   */
 110
 111 tree
 112 canonicalize_constructor_val (tree cval)
 113 {
 114   STRIP_NOPS (cval);
 115   if (TREE_CODE (cval) == POINTER_PLUS_EXPR)
 116     {
 117       tree t = maybe_fold_offset_to_address (EXPR_LOCATION (cval),
 118                                              TREE_OPERAND (cval, 0),
 119                                              TREE_OPERAND (cval, 1),
 120                                              TREE_TYPE (cval));
 121       if (t)
 122         cval = t;
 123     }
 124   if (TREE_CODE (cval) == ADDR_EXPR)
 125     {
 126       tree base = get_base_address (TREE_OPERAND (cval, 0));
 127
 128       if (base
 129           && (TREE_CODE (base) == VAR_DECL
 130               || TREE_CODE (base) == FUNCTION_DECL)
 131           && !can_refer_decl_in_current_unit_p (base))
 132         return NULL_TREE;
 133       if (base && TREE_CODE (base) == VAR_DECL)
 134         add_referenced_var (base);
 135       /* We never have the chance to fixup types in global initializers
 136          during gimplification.  Do so here.  */
 137       if (TREE_TYPE (TREE_TYPE (cval)) != TREE_TYPE (TREE_OPERAND (cval, 0)))
 138         cval = build_fold_addr_expr (TREE_OPERAND (cval, 0));
 139     }
 140   return cval;
 141 }
 142
 143 /* If SYM is a constant variable with known value, return the value.
 144    NULL_TREE is returned otherwise.  */
 145
 146 tree
 147 get_symbol_constant_value (tree sym)
 148 {
 149   if (const_value_known_p (sym))
 150     {
 151       tree val = DECL_INITIAL (sym);
 152       if (val)
 153         {
 154           val = canonicalize_constructor_val (val);
 155           if (val && is_gimple_min_invariant (val))
 156             return val;
 157           else
 158             return NULL_TREE;
 159         }
 160       /* Variables declared 'const' without an initializer
 161          have zero as the initializer if they may not be
 162          overridden at link or run time.  */
 163       if (!val
 164           && (INTEGRAL_TYPE_P (TREE_TYPE (sym))
 165                || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym))))
 166         return build_zero_cst (TREE_TYPE (sym));
 167     }
 168
 169   return NULL_TREE;
 170 }
 171
 172
 173 /* Return true if we may propagate the address expression ADDR into the
 174    dereference DEREF and cancel them.  */
 175
 176 bool
 177 may_propagate_address_into_dereference (tree addr, tree deref)
 178 {
 179   gcc_assert (TREE_CODE (deref) == MEM_REF
 180               && TREE_CODE (addr) == ADDR_EXPR);
 181
 182   /* Don't propagate if ADDR's operand has incomplete type.  */
 183   if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_OPERAND (addr, 0))))
 184     return false;
 185
 186   /* If the address is invariant then we do not need to preserve restrict
 187      qualifications.  But we do need to preserve volatile qualifiers until
 188      we can annotate the folded dereference itself properly.  */
 189   if (is_gimple_min_invariant (addr)
 190       && (!TREE_THIS_VOLATILE (deref)
 191           || TYPE_VOLATILE (TREE_TYPE (addr))))
 192     return useless_type_conversion_p (TREE_TYPE (deref),
 193                                       TREE_TYPE (TREE_OPERAND (addr, 0)));
 194
 195   /* Else both the address substitution and the folding must result in
 196      a valid useless type conversion sequence.  */
 197   return (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (deref, 0)),
 198                                      TREE_TYPE (addr))
 199           && useless_type_conversion_p (TREE_TYPE (deref),
 200                                         TREE_TYPE (TREE_OPERAND (addr, 0))));
 201 }
 202
 203
 204 /* A subroutine of fold_stmt.  Attempts to fold *(A+O) to A[X].
 205    BASE is an array type.  OFFSET is a byte displacement.
 206
 207    LOC is the location of the original expression.  */
 208
 209 static tree
 210 maybe_fold_offset_to_array_ref (location_t loc, tree base, tree offset)
 211 {
 212   tree min_idx, idx, idx_type, elt_offset = integer_zero_node;
 213   tree array_type, elt_type, elt_size;
 214   tree domain_type;
 215
 216   /* If BASE is an ARRAY_REF, we can pick up another offset (this time
 217      measured in units of the size of elements type) from that ARRAY_REF).
 218      We can't do anything if either is variable.
 219
 220      The case we handle here is *(&A[N]+O).  */
 221   if (TREE_CODE (base) == ARRAY_REF)
 222     {
 223       tree low_bound = array_ref_low_bound (base);
 224
 225       elt_offset = TREE_OPERAND (base, 1);
 226       if (TREE_CODE (low_bound) != INTEGER_CST
 227           || TREE_CODE (elt_offset) != INTEGER_CST)
 228         return NULL_TREE;
 229
 230       elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0);
 231       base = TREE_OPERAND (base, 0);
 232     }
 233
 234   /* Ignore stupid user tricks of indexing non-array variables.  */
 235   array_type = TREE_TYPE (base);
 236   if (TREE_CODE (array_type) != ARRAY_TYPE)
 237     return NULL_TREE;
 238   elt_type = TREE_TYPE (array_type);
 239
 240   /* Use signed size type for intermediate computation on the index.  */
 241   idx_type = ssizetype;
 242
 243   /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the
 244      element type (so we can use the alignment if it's not constant).
 245      Otherwise, compute the offset as an index by using a division.  If the
 246      division isn't exact, then don't do anything.  */
 247   elt_size = TYPE_SIZE_UNIT (elt_type);
 248   if (!elt_size)
 249     return NULL;
 250   if (integer_zerop (offset))
 251     {
 252       if (TREE_CODE (elt_size) != INTEGER_CST)
 253         elt_size = size_int (TYPE_ALIGN (elt_type));
 254
 255       idx = build_int_cst (idx_type, 0);
 256     }
 257   else
 258     {
 259       unsigned HOST_WIDE_INT lquo, lrem;
 260       HOST_WIDE_INT hquo, hrem;
 261       double_int soffset;
 262
 263       /* The final array offset should be signed, so we need
 264          to sign-extend the (possibly pointer) offset here
 265          and use signed division.  */
 266       soffset = double_int_sext (tree_to_double_int (offset),
 267                                  TYPE_PRECISION (TREE_TYPE (offset)));
 268       if (TREE_CODE (elt_size) != INTEGER_CST
 269           || div_and_round_double (TRUNC_DIV_EXPR, 0,
 270                                    soffset.low, soffset.high,
 271                                    TREE_INT_CST_LOW (elt_size),
 272                                    TREE_INT_CST_HIGH (elt_size),
 273                                    &lquo, &hquo, &lrem, &hrem)
 274           || lrem || hrem)
 275         return NULL_TREE;
 276
 277       idx = build_int_cst_wide (idx_type, lquo, hquo);
 278     }
 279
 280   /* Assume the low bound is zero.  If there is a domain type, get the
 281      low bound, if any, convert the index into that type, and add the
 282      low bound.  */
 283   min_idx = build_int_cst (idx_type, 0);
 284   domain_type = TYPE_DOMAIN (array_type);
 285   if (domain_type)
 286     {
 287       idx_type = domain_type;
 288       if (TYPE_MIN_VALUE (idx_type))
 289         min_idx = TYPE_MIN_VALUE (idx_type);
 290       else
 291         min_idx = fold_convert (idx_type, min_idx);
 292
 293       if (TREE_CODE (min_idx) != INTEGER_CST)
 294         return NULL_TREE;
 295
 296       elt_offset = fold_convert (idx_type, elt_offset);
 297     }
 298
 299   if (!integer_zerop (min_idx))
 300     idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0);
 301   if (!integer_zerop (elt_offset))
 302     idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0);
 303
 304   /* Make sure to possibly truncate late after offsetting.  */
 305   idx = fold_convert (idx_type, idx);
 306
 307   /* We don't want to construct access past array bounds. For example
 308        char *(c[4]);
 309        c[3][2];
 310      should not be simplified into (*c)[14] or tree-vrp will
 311      give false warnings.
 312      This is only an issue for multi-dimensional arrays.  */
 313   if (TREE_CODE (elt_type) == ARRAY_TYPE
 314       && domain_type)
 315     {
 316       if (TYPE_MAX_VALUE (domain_type)
 317           && TREE_CODE (TYPE_MAX_VALUE (domain_type)) == INTEGER_CST
 318           && tree_int_cst_lt (TYPE_MAX_VALUE (domain_type), idx))
 319         return NULL_TREE;
 320       else if (TYPE_MIN_VALUE (domain_type)
 321                && TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST
 322                && tree_int_cst_lt (idx, TYPE_MIN_VALUE (domain_type)))
 323         return NULL_TREE;
 324       else if (compare_tree_int (idx, 0) < 0)
 325         return NULL_TREE;
 326     }
 327
 328   {
 329     tree t = build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE);
 330     SET_EXPR_LOCATION (t, loc);
 331     return t;
 332   }
 333 }
 334
 335
 336 /* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE[index].
 337    LOC is the location of original expression.
 338
 339    Before attempting the conversion strip off existing ADDR_EXPRs.  */
 340
 341 tree
 342 maybe_fold_offset_to_reference (location_t loc, tree base, tree offset,
 343                                 tree orig_type)
 344 {
 345   tree ret;
 346
 347   STRIP_NOPS (base);
 348   if (TREE_CODE (base) != ADDR_EXPR)
 349     return NULL_TREE;
 350
 351   base = TREE_OPERAND (base, 0);
 352   if (types_compatible_p (orig_type, TREE_TYPE (base))
 353       && integer_zerop (offset))
 354     return base;
 355
 356   ret = maybe_fold_offset_to_array_ref (loc, base, offset);
 357   if (ret && types_compatible_p (orig_type, TREE_TYPE (ret)))
 358     return ret;
 359   return NULL_TREE;
 360 }
 361
 362 /* Attempt to express (ORIG_TYPE)ADDR+OFFSET as (*ADDR)[index].
 363    LOC is the location of the original expression.  */
 364
 365 tree
 366 maybe_fold_offset_to_address (location_t loc, tree addr, tree offset,
 367                               tree orig_type)
 368 {
 369   tree base, ret;
 370
 371   STRIP_NOPS (addr);
 372   if (TREE_CODE (addr) != ADDR_EXPR)
 373     return NULL_TREE;
 374   base = TREE_OPERAND (addr, 0);
 375   ret = maybe_fold_offset_to_array_ref (loc, base, offset);
 376   if (ret)
 377     {
 378       ret = build_fold_addr_expr (ret);
 379       if (!useless_type_conversion_p (orig_type, TREE_TYPE (ret)))
 380         return NULL_TREE;
 381       SET_EXPR_LOCATION (ret, loc);
 382     }
 383
 384   return ret;
 385 }
 386
 387
 388 /* A quaint feature extant in our address arithmetic is that there
 389    can be hidden type changes here.  The type of the result need
 390    not be the same as the type of the input pointer.
 391
 392    What we're after here is an expression of the form
 393         (T *)(&array + const)
 394    where array is OP0, const is OP1, RES_TYPE is T and
 395    the cast doesn't actually exist, but is implicit in the
 396    type of the POINTER_PLUS_EXPR.  We'd like to turn this into
 397         &array[x]
 398    which may be able to propagate further.  */
 399
 400 tree
 401 maybe_fold_stmt_addition (location_t loc, tree res_type, tree op0, tree op1)
 402 {
 403   tree ptd_type;
 404   tree t;
 405
 406   /* The first operand should be an ADDR_EXPR.  */
 407   if (TREE_CODE (op0) != ADDR_EXPR)
 408     return NULL_TREE;
 409   op0 = TREE_OPERAND (op0, 0);
 410
 411   /* It had better be a constant.  */
 412   if (TREE_CODE (op1) != INTEGER_CST)
 413     {
 414       /* Or op0 should now be A[0] and the non-constant offset defined
 415          via a multiplication by the array element size.  */
 416       if (TREE_CODE (op0) == ARRAY_REF
 417           /* As we will end up creating a variable index array access
 418              in the outermost array dimension make sure there isn't
 419              a more inner array that the index could overflow to.  */
 420           && TREE_CODE (TREE_OPERAND (op0, 0)) != ARRAY_REF
 421           && integer_zerop (TREE_OPERAND (op0, 1))
 422           && TREE_CODE (op1) == SSA_NAME)
 423         {
 424           gimple offset_def = SSA_NAME_DEF_STMT (op1);
 425           tree elsz = TYPE_SIZE_UNIT (TREE_TYPE (op0));
 426           if (!host_integerp (elsz, 1)
 427               || !is_gimple_assign (offset_def))
 428             return NULL_TREE;
 429
 430           /* Do not build array references of something that we can't
 431              see the true number of array dimensions for.  */
 432           if (!DECL_P (TREE_OPERAND (op0, 0))
 433               && !handled_component_p (TREE_OPERAND (op0, 0)))
 434             return NULL_TREE;
 435
 436           if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
 437               && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
 438               && tree_int_cst_equal (gimple_assign_rhs2 (offset_def), elsz))
 439             return build_fold_addr_expr
 440                           (build4 (ARRAY_REF, TREE_TYPE (op0),
 441                                    TREE_OPERAND (op0, 0),
 442                                    gimple_assign_rhs1 (offset_def),
 443                                    TREE_OPERAND (op0, 2),
 444                                    TREE_OPERAND (op0, 3)));
 445           else if (integer_onep (elsz)
 446                    && gimple_assign_rhs_code (offset_def) != MULT_EXPR)
 447             return build_fold_addr_expr
 448                           (build4 (ARRAY_REF, TREE_TYPE (op0),
 449                                    TREE_OPERAND (op0, 0),
 450                                    op1,
 451                                    TREE_OPERAND (op0, 2),
 452                                    TREE_OPERAND (op0, 3)));
 453         }
 454       else if (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
 455                /* Dto.  */
 456                && TREE_CODE (TREE_TYPE (TREE_TYPE (op0))) != ARRAY_TYPE
 457                && TREE_CODE (op1) == SSA_NAME)
 458         {
 459           gimple offset_def = SSA_NAME_DEF_STMT (op1);
 460           tree elsz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (op0)));
 461           if (!host_integerp (elsz, 1)
 462               || !is_gimple_assign (offset_def))
 463             return NULL_TREE;
 464
 465           /* Do not build array references of something that we can't
 466              see the true number of array dimensions for.  */
 467           if (!DECL_P (op0)
 468               && !handled_component_p (op0))
 469             return NULL_TREE;
 470
 471           if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
 472               && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
 473               && tree_int_cst_equal (gimple_assign_rhs2 (offset_def), elsz))
 474             return build_fold_addr_expr
 475                           (build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (op0)),
 476                                    op0, gimple_assign_rhs1 (offset_def),
 477                                    integer_zero_node, NULL_TREE));
 478           else if (integer_onep (elsz)
 479                    && gimple_assign_rhs_code (offset_def) != MULT_EXPR)
 480             return build_fold_addr_expr
 481                           (build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (op0)),
 482                                    op0, op1,
 483                                    integer_zero_node, NULL_TREE));
 484         }
 485
 486       return NULL_TREE;
 487     }
 488
 489   /* If the first operand is an ARRAY_REF, expand it so that we can fold
 490      the offset into it.  */
 491   while (TREE_CODE (op0) == ARRAY_REF)
 492     {
 493       tree array_obj = TREE_OPERAND (op0, 0);
 494       tree array_idx = TREE_OPERAND (op0, 1);
 495       tree elt_type = TREE_TYPE (op0);
 496       tree elt_size = TYPE_SIZE_UNIT (elt_type);
 497       tree min_idx;
 498
 499       if (TREE_CODE (array_idx) != INTEGER_CST)
 500         break;
 501       if (TREE_CODE (elt_size) != INTEGER_CST)
 502         break;
 503
 504       /* Un-bias the index by the min index of the array type.  */
 505       min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj));
 506       if (min_idx)
 507         {
 508           min_idx = TYPE_MIN_VALUE (min_idx);
 509           if (min_idx)
 510             {
 511               if (TREE_CODE (min_idx) != INTEGER_CST)
 512                 break;
 513
 514               array_idx = fold_convert (TREE_TYPE (min_idx), array_idx);
 515               if (!integer_zerop (min_idx))
 516                 array_idx = int_const_binop (MINUS_EXPR, array_idx,
 517                                              min_idx, 0);
 518             }
 519         }
 520
 521       /* Convert the index to a byte offset.  */
 522       array_idx = fold_convert (sizetype, array_idx);
 523       array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0);
 524
 525       /* Update the operands for the next round, or for folding.  */
 526       op1 = int_const_binop (PLUS_EXPR,
 527                              array_idx, op1, 0);
 528       op0 = array_obj;
 529     }
 530
 531   ptd_type = TREE_TYPE (res_type);
 532   /* If we want a pointer to void, reconstruct the reference from the
 533      array element type.  A pointer to that can be trivially converted
 534      to void *.  This happens as we fold (void *)(ptr p+ off).  */
 535   if (VOID_TYPE_P (ptd_type)
 536       && TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE)
 537     ptd_type = TREE_TYPE (TREE_TYPE (op0));
 538
 539   /* At which point we can try some of the same things as for indirects.  */
 540   t = maybe_fold_offset_to_array_ref (loc, op0, op1);
 541   if (t)
 542     {
 543       t = build_fold_addr_expr (t);
 544       if (!useless_type_conversion_p (res_type, TREE_TYPE (t)))
 545         return NULL_TREE;
 546       SET_EXPR_LOCATION (t, loc);
 547     }
 548
 549   return t;
 550 }
 551
 552 /* Subroutine of fold_stmt.  We perform several simplifications of the
 553    memory reference tree EXPR and make sure to re-gimplify them properly
 554    after propagation of constant addresses.  IS_LHS is true if the
 555    reference is supposed to be an lvalue.  */
 556
 557 static tree
 558 maybe_fold_reference (tree expr, bool is_lhs)
 559 {
 560   tree *t = &expr;
 561   tree result;
 562
 563   if (!is_lhs
 564       && (result = fold_const_aggregate_ref (expr))
 565       && is_gimple_min_invariant (result))
 566     return result;
 567
 568   /* ???  We might want to open-code the relevant remaining cases
 569      to avoid using the generic fold.  */
 570   if (handled_component_p (*t)
 571       && CONSTANT_CLASS_P (TREE_OPERAND (*t, 0)))
 572     {
 573       tree tem = fold (*t);
 574       if (tem != *t)
 575         return tem;
 576     }
 577
 578   while (handled_component_p (*t))
 579     t = &TREE_OPERAND (*t, 0);
 580
 581   /* Fold back MEM_REFs to reference trees.  */
 582   if (TREE_CODE (*t) == MEM_REF
 583       && TREE_CODE (TREE_OPERAND (*t, 0)) == ADDR_EXPR
 584       && integer_zerop (TREE_OPERAND (*t, 1))
 585       && (TREE_THIS_VOLATILE (*t)
 586           == TREE_THIS_VOLATILE (TREE_OPERAND (TREE_OPERAND (*t, 0), 0)))
 587       && !TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (TREE_OPERAND (*t, 1)))
 588       && (TYPE_MAIN_VARIANT (TREE_TYPE (*t))
 589           == TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (TREE_OPERAND (*t, 1)))))
 590       /* We have to look out here to not drop a required conversion
 591          from the rhs to the lhs if is_lhs, but we don't have the
 592          rhs here to verify that.  Thus require strict type
 593          compatibility.  */
 594       && types_compatible_p (TREE_TYPE (*t),
 595                              TREE_TYPE (TREE_OPERAND
 596                                           (TREE_OPERAND (*t, 0), 0))))
 597     {
 598       tree tem;
 599       *t = TREE_OPERAND (TREE_OPERAND (*t, 0), 0);
 600       tem = maybe_fold_reference (expr, is_lhs);
 601       if (tem)
 602         return tem;
 603       return expr;
 604     }
 605   /* Canonicalize MEM_REFs invariant address operand.  */
 606   else if (TREE_CODE (*t) == MEM_REF
 607            && !is_gimple_mem_ref_addr (TREE_OPERAND (*t, 0)))
 608     {
 609       bool volatile_p = TREE_THIS_VOLATILE (*t);
 610       tree tem = fold_binary (MEM_REF, TREE_TYPE (*t),
 611                               TREE_OPERAND (*t, 0),
 612                               TREE_OPERAND (*t, 1));
 613       if (tem)
 614         {
 615           TREE_THIS_VOLATILE (tem) = volatile_p;
 616           *t = tem;
 617           tem = maybe_fold_reference (expr, is_lhs);
 618           if (tem)
 619             return tem;
 620           return expr;
 621         }
 622     }
 623   else if (TREE_CODE (*t) == TARGET_MEM_REF)
 624     {
 625       tree tem = maybe_fold_tmr (*t);
 626       if (tem)
 627         {
 628           *t = tem;
 629           tem = maybe_fold_reference (expr, is_lhs);
 630           if (tem)
 631             return tem;
 632           return expr;
 633         }
 634     }
 635   else if (!is_lhs
 636            && DECL_P (*t))
 637     {
 638       tree tem = get_symbol_constant_value (*t);
 639       if (tem
 640           && useless_type_conversion_p (TREE_TYPE (*t), TREE_TYPE (tem)))
 641         {
 642           *t = unshare_expr (tem);
 643           tem = maybe_fold_reference (expr, is_lhs);
 644           if (tem)
 645             return tem;
 646           return expr;
 647         }
 648     }
 649
 650   return NULL_TREE;
 651 }
 652
 653
 654 /* Attempt to fold an assignment statement pointed-to by SI.  Returns a
 655    replacement rhs for the statement or NULL_TREE if no simplification
 656    could be made.  It is assumed that the operands have been previously
 657    folded.  */
 658
 659 static tree
 660 fold_gimple_assign (gimple_stmt_iterator *si)
 661 {
 662   gimple stmt = gsi_stmt (*si);
 663   enum tree_code subcode = gimple_assign_rhs_code (stmt);
 664   location_t loc = gimple_location (stmt);
 665
 666   tree result = NULL_TREE;
 667
 668   switch (get_gimple_rhs_class (subcode))
 669     {
 670     case GIMPLE_SINGLE_RHS:
 671       {
 672         tree rhs = gimple_assign_rhs1 (stmt);
 673
 674         /* Try to fold a conditional expression.  */
 675         if (TREE_CODE (rhs) == COND_EXPR)
 676           {
 677             tree op0 = COND_EXPR_COND (rhs);
 678             tree tem;
 679             bool set = false;
 680             location_t cond_loc = EXPR_LOCATION (rhs);
 681
 682             if (COMPARISON_CLASS_P (op0))
 683               {
 684                 fold_defer_overflow_warnings ();
 685                 tem = fold_binary_loc (cond_loc,
 686                                    TREE_CODE (op0), TREE_TYPE (op0),
 687                                    TREE_OPERAND (op0, 0),
 688                                    TREE_OPERAND (op0, 1));
 689                 /* This is actually a conditional expression, not a GIMPLE
 690                    conditional statement, however, the valid_gimple_rhs_p
 691                    test still applies.  */
 692                 set = (tem && is_gimple_condexpr (tem)
 693                        && valid_gimple_rhs_p (tem));
 694                 fold_undefer_overflow_warnings (set, stmt, 0);
 695               }
 696             else if (is_gimple_min_invariant (op0))
 697               {
 698                 tem = op0;
 699                 set = true;
 700               }
 701             else
 702               return NULL_TREE;
 703
 704             if (set)
 705               result = fold_build3_loc (cond_loc, COND_EXPR, TREE_TYPE (rhs), tem,
 706                                     COND_EXPR_THEN (rhs), COND_EXPR_ELSE (rhs));
 707           }
 708
 709         else if (REFERENCE_CLASS_P (rhs))
 710           return maybe_fold_reference (rhs, false);
 711
 712         else if (TREE_CODE (rhs) == ADDR_EXPR)
 713           {
 714             tree ref = TREE_OPERAND (rhs, 0);
 715             tree tem = maybe_fold_reference (ref, true);
 716             if (tem
 717                 && TREE_CODE (tem) == MEM_REF
 718                 && integer_zerop (TREE_OPERAND (tem, 1)))
 719               result = fold_convert (TREE_TYPE (rhs), TREE_OPERAND (tem, 0));
 720             else if (tem)
 721               result = fold_convert (TREE_TYPE (rhs),
 722                                      build_fold_addr_expr_loc (loc, tem));
 723             else if (TREE_CODE (ref) == MEM_REF
 724                      && integer_zerop (TREE_OPERAND (ref, 1)))
 725               result = fold_convert (TREE_TYPE (rhs), TREE_OPERAND (ref, 0));
 726           }
 727
 728         else if (TREE_CODE (rhs) == CONSTRUCTOR
 729                  && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE
 730                  && (CONSTRUCTOR_NELTS (rhs)
 731                      == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs))))
 732           {
 733             /* Fold a constant vector CONSTRUCTOR to VECTOR_CST.  */
 734             unsigned i;
 735             tree val;
 736
 737             FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val)
 738               if (TREE_CODE (val) != INTEGER_CST
 739                   && TREE_CODE (val) != REAL_CST
 740                   && TREE_CODE (val) != FIXED_CST)
 741                 return NULL_TREE;
 742
 743             return build_vector_from_ctor (TREE_TYPE (rhs),
 744                                            CONSTRUCTOR_ELTS (rhs));
 745           }
 746
 747         else if (DECL_P (rhs))
 748           return unshare_expr (get_symbol_constant_value (rhs));
 749
 750         /* If we couldn't fold the RHS, hand over to the generic
 751            fold routines.  */
 752         if (result == NULL_TREE)
 753           result = fold (rhs);
 754
 755         /* Strip away useless type conversions.  Both the NON_LVALUE_EXPR
 756            that may have been added by fold, and "useless" type
 757            conversions that might now be apparent due to propagation.  */
 758         STRIP_USELESS_TYPE_CONVERSION (result);
 759
 760         if (result != rhs && valid_gimple_rhs_p (result))
 761           return result;
 762
 763         return NULL_TREE;
 764       }
 765       break;
 766
 767     case GIMPLE_UNARY_RHS:
 768       {
 769         tree rhs = gimple_assign_rhs1 (stmt);
 770
 771         result = fold_unary_loc (loc, subcode, gimple_expr_type (stmt), rhs);
 772         if (result)
 773           {
 774             /* If the operation was a conversion do _not_ mark a
 775                resulting constant with TREE_OVERFLOW if the original
 776                constant was not.  These conversions have implementation
 777                defined behavior and retaining the TREE_OVERFLOW flag
 778                here would confuse later passes such as VRP.  */
 779             if (CONVERT_EXPR_CODE_P (subcode)
 780                 && TREE_CODE (result) == INTEGER_CST
 781                 && TREE_CODE (rhs) == INTEGER_CST)
 782               TREE_OVERFLOW (result) = TREE_OVERFLOW (rhs);
 783
 784             STRIP_USELESS_TYPE_CONVERSION (result);
 785             if (valid_gimple_rhs_p (result))
 786               return result;
 787           }
 788         else if (CONVERT_EXPR_CODE_P (subcode)
 789                  && POINTER_TYPE_P (gimple_expr_type (stmt))
 790                  && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
 791           {
 792             tree type = gimple_expr_type (stmt);
 793             tree t = maybe_fold_offset_to_address (loc,
 794                                                    gimple_assign_rhs1 (stmt),
 795                                                    integer_zero_node, type);
 796             if (t)
 797               return t;
 798           }
 799       }
 800       break;
 801
 802     case GIMPLE_BINARY_RHS:
 803       /* Try to fold pointer addition.  */
 804       if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
 805         {
 806           tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
 807           if (TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE)
 808             {
 809               type = build_pointer_type (TREE_TYPE (TREE_TYPE (type)));
 810               if (!useless_type_conversion_p
 811                     (TREE_TYPE (gimple_assign_lhs (stmt)), type))
 812                 type = TREE_TYPE (gimple_assign_rhs1 (stmt));
 813             }
 814           result = maybe_fold_stmt_addition (gimple_location (stmt),
 815                                              type,
 816                                              gimple_assign_rhs1 (stmt),
 817                                              gimple_assign_rhs2 (stmt));
 818         }
 819
 820       if (!result)
 821         result = fold_binary_loc (loc, subcode,
 822                               TREE_TYPE (gimple_assign_lhs (stmt)),
 823                               gimple_assign_rhs1 (stmt),
 824                               gimple_assign_rhs2 (stmt));
 825
 826       if (result)
 827         {
 828           STRIP_USELESS_TYPE_CONVERSION (result);
 829           if (valid_gimple_rhs_p (result))
 830             return result;
 831
 832           /* Fold might have produced non-GIMPLE, so if we trust it blindly
 833              we lose canonicalization opportunities.  Do not go again
 834              through fold here though, or the same non-GIMPLE will be
 835              produced.  */
 836           if (commutative_tree_code (subcode)
 837               && tree_swap_operands_p (gimple_assign_rhs1 (stmt),
 838                                        gimple_assign_rhs2 (stmt), false))
 839             return build2 (subcode, TREE_TYPE (gimple_assign_lhs (stmt)),
 840                            gimple_assign_rhs2 (stmt),
 841                            gimple_assign_rhs1 (stmt));
 842         }
 843       break;
 844
 845     case GIMPLE_TERNARY_RHS:
 846       result = fold_ternary_loc (loc, subcode,
 847                                  TREE_TYPE (gimple_assign_lhs (stmt)),
 848                                  gimple_assign_rhs1 (stmt),
 849                                  gimple_assign_rhs2 (stmt),
 850                                  gimple_assign_rhs3 (stmt));
 851
 852       if (result)
 853         {
 854           STRIP_USELESS_TYPE_CONVERSION (result);
 855           if (valid_gimple_rhs_p (result))
 856             return result;
 857
 858           /* Fold might have produced non-GIMPLE, so if we trust it blindly
 859              we lose canonicalization opportunities.  Do not go again
 860              through fold here though, or the same non-GIMPLE will be
 861              produced.  */
 862           if (commutative_ternary_tree_code (subcode)
 863               && tree_swap_operands_p (gimple_assign_rhs1 (stmt),
 864                                        gimple_assign_rhs2 (stmt), false))
 865             return build3 (subcode, TREE_TYPE (gimple_assign_lhs (stmt)),
 866                            gimple_assign_rhs2 (stmt),
 867                            gimple_assign_rhs1 (stmt),
 868                            gimple_assign_rhs3 (stmt));
 869         }
 870       break;
 871
 872     case GIMPLE_INVALID_RHS:
 873       gcc_unreachable ();
 874     }
 875
 876   return NULL_TREE;
 877 }
 878
 879 /* Attempt to fold a conditional statement. Return true if any changes were
 880    made. We only attempt to fold the condition expression, and do not perform
 881    any transformation that would require alteration of the cfg.  It is
 882    assumed that the operands have been previously folded.  */
 883
 884 static bool
 885 fold_gimple_cond (gimple stmt)
 886 {
 887   tree result = fold_binary_loc (gimple_location (stmt),
 888                              gimple_cond_code (stmt),
 889                              boolean_type_node,
 890                              gimple_cond_lhs (stmt),
 891                              gimple_cond_rhs (stmt));
 892
 893   if (result)
 894     {
 895       STRIP_USELESS_TYPE_CONVERSION (result);
 896       if (is_gimple_condexpr (result) && valid_gimple_rhs_p (result))
 897         {
 898           gimple_cond_set_condition_from_tree (stmt, result);
 899           return true;
 900         }
 901     }
 902
 903   return false;
 904 }
 905
 906 /* Convert EXPR into a GIMPLE value suitable for substitution on the
 907    RHS of an assignment.  Insert the necessary statements before
 908    iterator *SI_P.  The statement at *SI_P, which must be a GIMPLE_CALL
 909    is replaced.  If the call is expected to produces a result, then it
 910    is replaced by an assignment of the new RHS to the result variable.
 911    If the result is to be ignored, then the call is replaced by a
 912    GIMPLE_NOP.  A proper VDEF chain is retained by making the first
 913    VUSE and the last VDEF of the whole sequence be the same as the replaced
 914    statement and using new SSA names for stores in between.  */
 915
 916 void
 917 gimplify_and_update_call_from_tree (gimple_stmt_iterator *si_p, tree expr)
 918 {
 919   tree lhs;
 920   tree tmp = NULL_TREE;  /* Silence warning.  */
 921   gimple stmt, new_stmt;
 922   gimple_stmt_iterator i;
 923   gimple_seq stmts = gimple_seq_alloc();
 924   struct gimplify_ctx gctx;
 925   gimple last = NULL;
 926   gimple laststore = NULL;
 927   tree reaching_vuse;
 928
 929   stmt = gsi_stmt (*si_p);
 930
 931   gcc_assert (is_gimple_call (stmt));
 932
 933   lhs = gimple_call_lhs (stmt);
 934   reaching_vuse = gimple_vuse (stmt);
 935
 936   push_gimplify_context (&gctx);
 937
 938   if (lhs == NULL_TREE)
 939     {
 940       gimplify_and_add (expr, &stmts);
 941       /* We can end up with folding a memcpy of an empty class assignment
 942          which gets optimized away by C++ gimplification.  */
 943       if (gimple_seq_empty_p (stmts))
 944         {
 945           pop_gimplify_context (NULL);
 946           if (gimple_in_ssa_p (cfun))
 947             {
 948               unlink_stmt_vdef (stmt);
 949               release_defs (stmt);
 950             }
 951           gsi_remove (si_p, true);
 952           return;
 953         }
 954     }
 955   else
 956     tmp = get_initialized_tmp_var (expr, &stmts, NULL);
 957
 958   pop_gimplify_context (NULL);
 959
 960   if (gimple_has_location (stmt))
 961     annotate_all_with_location (stmts, gimple_location (stmt));
 962
 963   /* The replacement can expose previously unreferenced variables.  */
 964   for (i = gsi_start (stmts); !gsi_end_p (i); gsi_next (&i))
 965     {
 966       if (last)
 967         {
 968           gsi_insert_before (si_p, last, GSI_NEW_STMT);
 969           gsi_next (si_p);
 970         }
 971       new_stmt = gsi_stmt (i);
 972       if (gimple_in_ssa_p (cfun))
 973         {
 974           find_new_referenced_vars (new_stmt);
 975           mark_symbols_for_renaming (new_stmt);
 976         }
 977       /* If the new statement has a VUSE, update it with exact SSA name we
 978          know will reach this one.  */
 979       if (gimple_vuse (new_stmt))
 980         {
 981           /* If we've also seen a previous store create a new VDEF for
 982              the latter one, and make that the new reaching VUSE.  */
 983           if (laststore)
 984             {
 985               reaching_vuse = make_ssa_name (gimple_vop (cfun), laststore);
 986               gimple_set_vdef (laststore, reaching_vuse);
 987               update_stmt (laststore);
 988               laststore = NULL;
 989             }
 990           gimple_set_vuse (new_stmt, reaching_vuse);
 991           gimple_set_modified (new_stmt, true);
 992         }
 993       if (gimple_assign_single_p (new_stmt)
 994           && !is_gimple_reg (gimple_assign_lhs (new_stmt)))
 995         {
 996           laststore = new_stmt;
 997         }
 998       last = new_stmt;
 999     }
1000
1001   if (lhs == NULL_TREE)
1002     {
1003       /* If we replace a call without LHS that has a VDEF and our new
1004          sequence ends with a store we must make that store have the same
1005          vdef in order not to break the sequencing.  This can happen
1006          for instance when folding memcpy calls into assignments.  */
1007       if (gimple_vdef (stmt) && laststore)
1008         {
1009           gimple_set_vdef (laststore, gimple_vdef (stmt));
1010           if (TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
1011             SSA_NAME_DEF_STMT (gimple_vdef (stmt)) = laststore;
1012           update_stmt (laststore);
1013         }
1014       else if (gimple_in_ssa_p (cfun))
1015         {
1016           unlink_stmt_vdef (stmt);
1017           release_defs (stmt);
1018         }
1019       new_stmt = last;
1020     }
1021   else
1022     {
1023       if (last)
1024         {
1025           gsi_insert_before (si_p, last, GSI_NEW_STMT);
1026           gsi_next (si_p);
1027         }
1028       if (laststore && is_gimple_reg (lhs))
1029         {
1030           gimple_set_vdef (laststore, gimple_vdef (stmt));
1031           update_stmt (laststore);
1032           if (TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
1033             SSA_NAME_DEF_STMT (gimple_vdef (stmt)) = laststore;
1034           laststore = NULL;
1035         }
1036       else if (laststore)
1037         {
1038           reaching_vuse = make_ssa_name (gimple_vop (cfun), laststore);
1039           gimple_set_vdef (laststore, reaching_vuse);
1040           update_stmt (laststore);
1041           laststore = NULL;
1042         }
1043       new_stmt = gimple_build_assign (lhs, tmp);
1044       if (!is_gimple_reg (tmp))
1045         gimple_set_vuse (new_stmt, reaching_vuse);
1046       if (!is_gimple_reg (lhs))
1047         {
1048           gimple_set_vdef (new_stmt, gimple_vdef (stmt));
1049           if (TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
1050             SSA_NAME_DEF_STMT (gimple_vdef (stmt)) = new_stmt;
1051         }
1052       else if (reaching_vuse == gimple_vuse (stmt))
1053         unlink_stmt_vdef (stmt);
1054     }
1055
1056   gimple_set_location (new_stmt, gimple_location (stmt));
1057   gsi_replace (si_p, new_stmt, false);
1058 }
1059
1060 /* Return the string length, maximum string length or maximum value of
1061    ARG in LENGTH.
1062    If ARG is an SSA name variable, follow its use-def chains.  If LENGTH
1063    is not NULL and, for TYPE == 0, its value is not equal to the length
1064    we determine or if we are unable to determine the length or value,
1065    return false.  VISITED is a bitmap of visited variables.
1066    TYPE is 0 if string length should be returned, 1 for maximum string
1067    length and 2 for maximum value ARG can have.  */
1068
1069 static bool
1070 get_maxval_strlen (tree arg, tree *length, bitmap visited, int type)
1071 {
1072   tree var, val;
1073   gimple def_stmt;
1074
1075   if (TREE_CODE (arg) != SSA_NAME)
1076     {
1077       if (TREE_CODE (arg) == COND_EXPR)
1078         return get_maxval_strlen (COND_EXPR_THEN (arg), length, visited, type)
1079                && get_maxval_strlen (COND_EXPR_ELSE (arg), length, visited, type);
1080       /* We can end up with &(*iftmp_1)[0] here as well, so handle it.  */
1081       else if (TREE_CODE (arg) == ADDR_EXPR
1082                && TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF
1083                && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg, 0), 1)))
1084         {
1085           tree aop0 = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
1086           if (TREE_CODE (aop0) == INDIRECT_REF
1087               && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME)
1088             return get_maxval_strlen (TREE_OPERAND (aop0, 0),
1089                                       length, visited, type);
1090         }
1091
1092       if (type == 2)
1093         {
1094           val = arg;
1095           if (TREE_CODE (val) != INTEGER_CST
1096               || tree_int_cst_sgn (val) < 0)
1097             return false;
1098         }
1099       else
1100         val = c_strlen (arg, 1);
1101       if (!val)
1102         return false;
1103
1104       if (*length)
1105         {
1106           if (type > 0)
1107             {
1108               if (TREE_CODE (*length) != INTEGER_CST
1109                   || TREE_CODE (val) != INTEGER_CST)
1110                 return false;
1111
1112               if (tree_int_cst_lt (*length, val))
1113                 *length = val;
1114               return true;
1115             }
1116           else if (simple_cst_equal (val, *length) != 1)
1117             return false;
1118         }
1119
1120       *length = val;
1121       return true;
1122     }
1123
1124   /* If we were already here, break the infinite cycle.  */
1125   if (!bitmap_set_bit (visited, SSA_NAME_VERSION (arg)))
1126     return true;
1127
1128   var = arg;
1129   def_stmt = SSA_NAME_DEF_STMT (var);
1130
1131   switch (gimple_code (def_stmt))
1132     {
1133       case GIMPLE_ASSIGN:
1134         /* The RHS of the statement defining VAR must either have a
1135            constant length or come from another SSA_NAME with a constant
1136            length.  */
1137         if (gimple_assign_single_p (def_stmt)
1138             || gimple_assign_unary_nop_p (def_stmt))
1139           {
1140             tree rhs = gimple_assign_rhs1 (def_stmt);
1141             return get_maxval_strlen (rhs, length, visited, type);
1142           }
1143         return false;
1144
1145       case GIMPLE_PHI:
1146         {
1147           /* All the arguments of the PHI node must have the same constant
1148              length.  */
1149           unsigned i;
1150
1151           for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
1152           {
1153             tree arg = gimple_phi_arg (def_stmt, i)->def;
1154
1155             /* If this PHI has itself as an argument, we cannot
1156                determine the string length of this argument.  However,
1157                if we can find a constant string length for the other
1158                PHI args then we can still be sure that this is a
1159                constant string length.  So be optimistic and just
1160                continue with the next argument.  */
1161             if (arg == gimple_phi_result (def_stmt))
1162               continue;
1163
1164             if (!get_maxval_strlen (arg, length, visited, type))
1165               return false;
1166           }
1167         }
1168         return true;
1169
1170       default:
1171         return false;
1172     }
1173 }
1174
1175
1176 /* Fold builtin call in statement STMT.  Returns a simplified tree.
1177    We may return a non-constant expression, including another call
1178    to a different function and with different arguments, e.g.,
1179    substituting memcpy for strcpy when the string length is known.
1180    Note that some builtins expand into inline code that may not
1181    be valid in GIMPLE.  Callers must take care.  */
1182
1183 tree
1184 gimple_fold_builtin (gimple stmt)
1185 {
1186   tree result, val[3];
1187   tree callee, a;
1188   int arg_idx, type;
1189   bitmap visited;
1190   bool ignore;
1191   int nargs;
1192   location_t loc = gimple_location (stmt);
1193
1194   gcc_assert (is_gimple_call (stmt));
1195
1196   ignore = (gimple_call_lhs (stmt) == NULL);
1197
1198   /* First try the generic builtin folder.  If that succeeds, return the
1199      result directly.  */
1200   result = fold_call_stmt (stmt, ignore);
1201   if (result)
1202     {
1203       if (ignore)
1204         STRIP_NOPS (result);
1205       return result;
1206     }
1207
1208   /* Ignore MD builtins.  */
1209   callee = gimple_call_fndecl (stmt);
1210   if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD)
1211     return NULL_TREE;
1212
1213   /* Give up for always_inline inline builtins until they are
1214      inlined.  */
1215   if (avoid_folding_inline_builtin (callee))
1216     return NULL_TREE;
1217
1218   /* If the builtin could not be folded, and it has no argument list,
1219      we're done.  */
1220   nargs = gimple_call_num_args (stmt);
1221   if (nargs == 0)
1222     return NULL_TREE;
1223
1224   /* Limit the work only for builtins we know how to simplify.  */
1225   switch (DECL_FUNCTION_CODE (callee))
1226     {
1227     case BUILT_IN_STRLEN:
1228     case BUILT_IN_FPUTS:
1229     case BUILT_IN_FPUTS_UNLOCKED:
1230       arg_idx = 0;
1231       type = 0;
1232       break;
1233     case BUILT_IN_STRCPY:
1234     case BUILT_IN_STRNCPY:
1235       arg_idx = 1;
1236       type = 0;
1237       break;
1238     case BUILT_IN_MEMCPY_CHK:
1239     case BUILT_IN_MEMPCPY_CHK:
1240     case BUILT_IN_MEMMOVE_CHK:
1241     case BUILT_IN_MEMSET_CHK:
1242     case BUILT_IN_STRNCPY_CHK:
1243       arg_idx = 2;
1244       type = 2;
1245       break;
1246     case BUILT_IN_STRCPY_CHK:
1247     case BUILT_IN_STPCPY_CHK:
1248       arg_idx = 1;
1249       type = 1;
1250       break;
1251     case BUILT_IN_SNPRINTF_CHK:
1252     case BUILT_IN_VSNPRINTF_CHK:
1253       arg_idx = 1;
1254       type = 2;
1255       break;
1256     default:
1257       return NULL_TREE;
1258     }
1259
1260   if (arg_idx >= nargs)
1261     return NULL_TREE;
1262
1263   /* Try to use the dataflow information gathered by the CCP process.  */
1264   visited = BITMAP_ALLOC (NULL);
1265   bitmap_clear (visited);
1266
1267   memset (val, 0, sizeof (val));
1268   a = gimple_call_arg (stmt, arg_idx);
1269   if (!get_maxval_strlen (a, &val[arg_idx], visited, type))
1270     val[arg_idx] = NULL_TREE;
1271
1272   BITMAP_FREE (visited);
1273
1274   result = NULL_TREE;
1275   switch (DECL_FUNCTION_CODE (callee))
1276     {
1277     case BUILT_IN_STRLEN:
1278       if (val[0] && nargs == 1)
1279         {
1280           tree new_val =
1281               fold_convert (TREE_TYPE (gimple_call_lhs (stmt)), val[0]);
1282
1283           /* If the result is not a valid gimple value, or not a cast
1284              of a valid gimple value, then we cannot use the result.  */
1285           if (is_gimple_val (new_val)
1286               || (CONVERT_EXPR_P (new_val)
1287                   && is_gimple_val (TREE_OPERAND (new_val, 0))))
1288             return new_val;
1289         }
1290       break;
1291
1292     case BUILT_IN_STRCPY:
1293       if (val[1] && is_gimple_val (val[1]) && nargs == 2)
1294         result = fold_builtin_strcpy (loc, callee,
1295                                       gimple_call_arg (stmt, 0),
1296                                       gimple_call_arg (stmt, 1),
1297                                       val[1]);
1298       break;
1299
1300     case BUILT_IN_STRNCPY:
1301       if (val[1] && is_gimple_val (val[1]) && nargs == 3)
1302         result = fold_builtin_strncpy (loc, callee,
1303                                        gimple_call_arg (stmt, 0),
1304                                        gimple_call_arg (stmt, 1),
1305                                        gimple_call_arg (stmt, 2),
1306                                        val[1]);
1307       break;
1308
1309     case BUILT_IN_FPUTS:
1310       if (nargs == 2)
1311         result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
1312                                      gimple_call_arg (stmt, 1),
1313                                      ignore, false, val[0]);
1314       break;
1315
1316     case BUILT_IN_FPUTS_UNLOCKED:
1317       if (nargs == 2)
1318         result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
1319                                      gimple_call_arg (stmt, 1),
1320                                      ignore, true, val[0]);
1321       break;
1322
1323     case BUILT_IN_MEMCPY_CHK:
1324     case BUILT_IN_MEMPCPY_CHK:
1325     case BUILT_IN_MEMMOVE_CHK:
1326     case BUILT_IN_MEMSET_CHK:
1327       if (val[2] && is_gimple_val (val[2]) && nargs == 4)
1328         result = fold_builtin_memory_chk (loc, callee,
1329                                           gimple_call_arg (stmt, 0),
1330                                           gimple_call_arg (stmt, 1),
1331                                           gimple_call_arg (stmt, 2),
1332                                           gimple_call_arg (stmt, 3),
1333                                           val[2], ignore,
1334                                           DECL_FUNCTION_CODE (callee));
1335       break;
1336
1337     case BUILT_IN_STRCPY_CHK:
1338     case BUILT_IN_STPCPY_CHK:
1339       if (val[1] && is_gimple_val (val[1]) && nargs == 3)
1340         result = fold_builtin_stxcpy_chk (loc, callee,
1341                                           gimple_call_arg (stmt, 0),
1342                                           gimple_call_arg (stmt, 1),
1343                                           gimple_call_arg (stmt, 2),
1344                                           val[1], ignore,
1345                                           DECL_FUNCTION_CODE (callee));
1346       break;
1347
1348     case BUILT_IN_STRNCPY_CHK:
1349       if (val[2] && is_gimple_val (val[2]) && nargs == 4)
1350         result = fold_builtin_strncpy_chk (loc, gimple_call_arg (stmt, 0),
1351                                            gimple_call_arg (stmt, 1),
1352                                            gimple_call_arg (stmt, 2),
1353                                            gimple_call_arg (stmt, 3),
1354                                            val[2]);
1355       break;
1356
1357     case BUILT_IN_SNPRINTF_CHK:
1358     case BUILT_IN_VSNPRINTF_CHK:
1359       if (val[1] && is_gimple_val (val[1]))
1360         result = gimple_fold_builtin_snprintf_chk (stmt, val[1],
1361                                                    DECL_FUNCTION_CODE (callee));
1362       break;
1363
1364     default:
1365       gcc_unreachable ();
1366     }
1367
1368   if (result && ignore)
1369     result = fold_ignored_result (result);
1370   return result;
1371 }
1372
1373 /* Return a declaration of a function which an OBJ_TYPE_REF references. TOKEN
1374    is integer form of OBJ_TYPE_REF_TOKEN of the reference expression.
1375    KNOWN_BINFO carries the binfo describing the true type of
1376    OBJ_TYPE_REF_OBJECT(REF).  If a call to the function must be accompanied
1377    with a this adjustment, the constant which should be added to this pointer
1378    is stored to *DELTA.  If REFUSE_THUNKS is true, return NULL if the function
1379    is a thunk (other than a this adjustment which is dealt with by DELTA). */
1380
1381 tree
1382 gimple_get_virt_method_for_binfo (HOST_WIDE_INT token, tree known_binfo,
1383                                   tree *delta, bool refuse_thunks)
1384 {
1385   HOST_WIDE_INT i;
1386   tree v, fndecl;
1387   struct cgraph_node *node;
1388
1389   v = BINFO_VIRTUALS (known_binfo);
1390   /* If there is no virtual methods leave the OBJ_TYPE_REF alone.  */
1391   if (!v)
1392     return NULL_TREE;
1393   i = 0;
1394   while (i != token)
1395     {
1396       i += (TARGET_VTABLE_USES_DESCRIPTORS
1397             ? TARGET_VTABLE_USES_DESCRIPTORS : 1);
1398       v = TREE_CHAIN (v);
1399     }
1400
1401   /* If BV_VCALL_INDEX is non-NULL, give up.  */
1402   if (TREE_TYPE (v))
1403     return NULL_TREE;
1404
1405   fndecl = TREE_VALUE (v);
1406   node = cgraph_get_node_or_alias (fndecl);
1407   if (refuse_thunks
1408       && (!node
1409     /* Bail out if it is a thunk declaration.  Since simple this_adjusting
1410        thunks are represented by a constant in TREE_PURPOSE of items in
1411        BINFO_VIRTUALS, this is a more complicate type which we cannot handle as
1412        yet.
1413
1414        FIXME: Remove the following condition once we are able to represent
1415        thunk information on call graph edges.  */
1416           || (node->same_body_alias && node->thunk.thunk_p)))
1417     return NULL_TREE;
1418
1419   /* When cgraph node is missing and function is not public, we cannot
1420      devirtualize.  This can happen in WHOPR when the actual method
1421      ends up in other partition, because we found devirtualization
1422      possibility too late.  */
1423   if (!can_refer_decl_in_current_unit_p (TREE_VALUE (v)))
1424     return NULL_TREE;
1425
1426   *delta = TREE_PURPOSE (v);
1427   gcc_checking_assert (host_integerp (*delta, 0));
1428   return fndecl;
1429 }
1430
1431 /* Generate code adjusting the first parameter of a call statement determined
1432    by GSI by DELTA.  */
1433
1434 void
1435 gimple_adjust_this_by_delta (gimple_stmt_iterator *gsi, tree delta)
1436 {
1437   gimple call_stmt = gsi_stmt (*gsi);
1438   tree parm, tmp;
1439   gimple new_stmt;
1440
1441   delta = fold_convert (sizetype, delta);
1442   gcc_assert (gimple_call_num_args (call_stmt) >= 1);
1443   parm = gimple_call_arg (call_stmt, 0);
1444   gcc_assert (POINTER_TYPE_P (TREE_TYPE (parm)));
1445   tmp = create_tmp_var (TREE_TYPE (parm), NULL);
1446   add_referenced_var (tmp);
1447
1448   tmp = make_ssa_name (tmp, NULL);
1449   new_stmt = gimple_build_assign_with_ops (POINTER_PLUS_EXPR, tmp, parm, delta);
1450   SSA_NAME_DEF_STMT (tmp) = new_stmt;
1451   gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
1452   gimple_call_set_arg (call_stmt, 0, tmp);
1453 }
1454
1455 /* Attempt to fold a call statement referenced by the statement iterator GSI.
1456    The statement may be replaced by another statement, e.g., if the call
1457    simplifies to a constant value. Return true if any changes were made.
1458    It is assumed that the operands have been previously folded.  */
1459
1460 bool
1461 gimple_fold_call (gimple_stmt_iterator *gsi, bool inplace)
1462 {
1463   gimple stmt = gsi_stmt (*gsi);
1464
1465   tree callee = gimple_call_fndecl (stmt);
1466
1467   /* Check for builtins that CCP can handle using information not
1468      available in the generic fold routines.  */
1469   if (!inplace && callee && DECL_BUILT_IN (callee))
1470     {
1471       tree result = gimple_fold_builtin (stmt);
1472
1473       if (result)
1474         {
1475           if (!update_call_from_tree (gsi, result))
1476             gimplify_and_update_call_from_tree (gsi, result);
1477           return true;
1478         }
1479     }
1480   return false;
1481 }
1482
1483 /* Worker for both fold_stmt and fold_stmt_inplace.  The INPLACE argument
1484    distinguishes both cases.  */
1485
1486 static bool
1487 fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace)
1488 {
1489   bool changed = false;
1490   gimple stmt = gsi_stmt (*gsi);
1491   unsigned i;
1492   gimple_stmt_iterator gsinext = *gsi;
1493   gimple next_stmt;
1494
1495   gsi_next (&gsinext);
1496   next_stmt = gsi_end_p (gsinext) ? NULL : gsi_stmt (gsinext);
1497
1498   /* Fold the main computation performed by the statement.  */
1499   switch (gimple_code (stmt))
1500     {
1501     case GIMPLE_ASSIGN:
1502       {
1503         unsigned old_num_ops = gimple_num_ops (stmt);
1504         tree new_rhs = fold_gimple_assign (gsi);
1505         tree lhs = gimple_assign_lhs (stmt);
1506         if (new_rhs
1507             && !useless_type_conversion_p (TREE_TYPE (lhs),
1508                                            TREE_TYPE (new_rhs)))
1509           new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs);
1510         if (new_rhs
1511             && (!inplace
1512                 || get_gimple_rhs_num_ops (TREE_CODE (new_rhs)) < old_num_ops))
1513           {
1514             gimple_assign_set_rhs_from_tree (gsi, new_rhs);
1515             changed = true;
1516           }
1517         break;
1518       }
1519
1520     case GIMPLE_COND:
1521       changed |= fold_gimple_cond (stmt);
1522       break;
1523
1524     case GIMPLE_CALL:
1525       /* Fold *& in call arguments.  */
1526       for (i = 0; i < gimple_call_num_args (stmt); ++i)
1527         if (REFERENCE_CLASS_P (gimple_call_arg (stmt, i)))
1528           {
1529             tree tmp = maybe_fold_reference (gimple_call_arg (stmt, i), false);
1530             if (tmp)
1531               {
1532                 gimple_call_set_arg (stmt, i, tmp);
1533                 changed = true;
1534               }
1535           }
1536       changed |= gimple_fold_call (gsi, inplace);
1537       break;
1538
1539     case GIMPLE_ASM:
1540       /* Fold *& in asm operands.  */
1541       {
1542         size_t noutputs;
1543         const char **oconstraints;
1544         const char *constraint;
1545         bool allows_mem, allows_reg;
1546
1547         noutputs = gimple_asm_noutputs (stmt);
1548         oconstraints = XALLOCAVEC (const char *, noutputs);
1549
1550         for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
1551           {
1552             tree link = gimple_asm_output_op (stmt, i);
1553             tree op = TREE_VALUE (link);
1554             oconstraints[i]
1555               = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1556             if (REFERENCE_CLASS_P (op)
1557                 && (op = maybe_fold_reference (op, true)) != NULL_TREE)
1558               {
1559                 TREE_VALUE (link) = op;
1560                 changed = true;
1561               }
1562           }
1563         for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
1564           {
1565             tree link = gimple_asm_input_op (stmt, i);
1566             tree op = TREE_VALUE (link);
1567             constraint
1568               = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1569             parse_input_constraint (&constraint, 0, 0, noutputs, 0,
1570                                     oconstraints, &allows_mem, &allows_reg);
1571             if (REFERENCE_CLASS_P (op)
1572                 && (op = maybe_fold_reference (op, !allows_reg && allows_mem))
1573                    != NULL_TREE)
1574               {
1575                 TREE_VALUE (link) = op;
1576                 changed = true;
1577               }
1578           }
1579       }
1580       break;
1581
1582     case GIMPLE_DEBUG:
1583       if (gimple_debug_bind_p (stmt))
1584         {
1585           tree val = gimple_debug_bind_get_value (stmt);
1586           if (val
1587               && REFERENCE_CLASS_P (val))
1588             {
1589               tree tem = maybe_fold_reference (val, false);
1590               if (tem)
1591                 {
1592                   gimple_debug_bind_set_value (stmt, tem);
1593                   changed = true;
1594                 }
1595             }
1596         }
1597       break;
1598
1599     default:;
1600     }
1601
1602   /* If stmt folds into nothing and it was the last stmt in a bb,
1603      don't call gsi_stmt.  */
1604   if (gsi_end_p (*gsi))
1605     {
1606       gcc_assert (next_stmt == NULL);
1607       return changed;
1608     }
1609
1610   stmt = gsi_stmt (*gsi);
1611
1612   /* Fold *& on the lhs.  Don't do this if stmt folded into nothing,
1613      as we'd changing the next stmt.  */
1614   if (gimple_has_lhs (stmt) && stmt != next_stmt)
1615     {
1616       tree lhs = gimple_get_lhs (stmt);
1617       if (lhs && REFERENCE_CLASS_P (lhs))
1618         {
1619           tree new_lhs = maybe_fold_reference (lhs, true);
1620           if (new_lhs)
1621             {
1622               gimple_set_lhs (stmt, new_lhs);
1623               changed = true;
1624             }
1625         }
1626     }
1627
1628   return changed;
1629 }
1630
1631 /* Fold the statement pointed to by GSI.  In some cases, this function may
1632    replace the whole statement with a new one.  Returns true iff folding
1633    makes any changes.
1634    The statement pointed to by GSI should be in valid gimple form but may
1635    be in unfolded state as resulting from for example constant propagation
1636    which can produce *&x = 0.  */
1637
1638 bool
1639 fold_stmt (gimple_stmt_iterator *gsi)
1640 {
1641   return fold_stmt_1 (gsi, false);
1642 }
1643
1644 /* Perform the minimal folding on statement STMT.  Only operations like
1645    *&x created by constant propagation are handled.  The statement cannot
1646    be replaced with a new one.  Return true if the statement was
1647    changed, false otherwise.
1648    The statement STMT should be in valid gimple form but may
1649    be in unfolded state as resulting from for example constant propagation
1650    which can produce *&x = 0.  */
1651
1652 bool
1653 fold_stmt_inplace (gimple stmt)
1654 {
1655   gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
1656   bool changed = fold_stmt_1 (&gsi, true);
1657   gcc_assert (gsi_stmt (gsi) == stmt);
1658   return changed;
1659 }
1660
1661 /* Canonicalize and possibly invert the boolean EXPR; return NULL_TREE
1662    if EXPR is null or we don't know how.
1663    If non-null, the result always has boolean type.  */
1664
1665 static tree
1666 canonicalize_bool (tree expr, bool invert)
1667 {
1668   if (!expr)
1669     return NULL_TREE;
1670   else if (invert)
1671     {
1672       if (integer_nonzerop (expr))
1673         return boolean_false_node;
1674       else if (integer_zerop (expr))
1675         return boolean_true_node;
1676       else if (TREE_CODE (expr) == SSA_NAME)
1677         return fold_build2 (EQ_EXPR, boolean_type_node, expr,
1678                             build_int_cst (TREE_TYPE (expr), 0));
1679       else if (TREE_CODE_CLASS (TREE_CODE (expr)) == tcc_comparison)
1680         return fold_build2 (invert_tree_comparison (TREE_CODE (expr), false),
1681                             boolean_type_node,
1682                             TREE_OPERAND (expr, 0),
1683                             TREE_OPERAND (expr, 1));
1684       else
1685         return NULL_TREE;
1686     }
1687   else
1688     {
1689       if (TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE)
1690         return expr;
1691       if (integer_nonzerop (expr))
1692         return boolean_true_node;
1693       else if (integer_zerop (expr))
1694         return boolean_false_node;
1695       else if (TREE_CODE (expr) == SSA_NAME)
1696         return fold_build2 (NE_EXPR, boolean_type_node, expr,
1697                             build_int_cst (TREE_TYPE (expr), 0));
1698       else if (TREE_CODE_CLASS (TREE_CODE (expr)) == tcc_comparison)
1699         return fold_build2 (TREE_CODE (expr),
1700                             boolean_type_node,
1701                             TREE_OPERAND (expr, 0),
1702                             TREE_OPERAND (expr, 1));
1703       else
1704         return NULL_TREE;
1705     }
1706 }
1707
1708 /* Check to see if a boolean expression EXPR is logically equivalent to the
1709    comparison (OP1 CODE OP2).  Check for various identities involving
1710    SSA_NAMEs.  */
1711
1712 static bool
1713 same_bool_comparison_p (const_tree expr, enum tree_code code,
1714                         const_tree op1, const_tree op2)
1715 {
1716   gimple s;
1717
1718   /* The obvious case.  */
1719   if (TREE_CODE (expr) == code
1720       && operand_equal_p (TREE_OPERAND (expr, 0), op1, 0)
1721       && operand_equal_p (TREE_OPERAND (expr, 1), op2, 0))
1722     return true;
1723
1724   /* Check for comparing (name, name != 0) and the case where expr
1725      is an SSA_NAME with a definition matching the comparison.  */
1726   if (TREE_CODE (expr) == SSA_NAME
1727       && TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE)
1728     {
1729       if (operand_equal_p (expr, op1, 0))
1730         return ((code == NE_EXPR && integer_zerop (op2))
1731                 || (code == EQ_EXPR && integer_nonzerop (op2)));
1732       s = SSA_NAME_DEF_STMT (expr);
1733       if (is_gimple_assign (s)
1734           && gimple_assign_rhs_code (s) == code
1735           && operand_equal_p (gimple_assign_rhs1 (s), op1, 0)
1736           && operand_equal_p (gimple_assign_rhs2 (s), op2, 0))
1737         return true;
1738     }
1739
1740   /* If op1 is of the form (name != 0) or (name == 0), and the definition
1741      of name is a comparison, recurse.  */
1742   if (TREE_CODE (op1) == SSA_NAME
1743       && TREE_CODE (TREE_TYPE (op1)) == BOOLEAN_TYPE)
1744     {
1745       s = SSA_NAME_DEF_STMT (op1);
1746       if (is_gimple_assign (s)
1747           && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison)
1748         {
1749           enum tree_code c = gimple_assign_rhs_code (s);
1750           if ((c == NE_EXPR && integer_zerop (op2))
1751               || (c == EQ_EXPR && integer_nonzerop (op2)))
1752             return same_bool_comparison_p (expr, c,
1753                                            gimple_assign_rhs1 (s),
1754                                            gimple_assign_rhs2 (s));
1755           if ((c == EQ_EXPR && integer_zerop (op2))
1756               || (c == NE_EXPR && integer_nonzerop (op2)))
1757             return same_bool_comparison_p (expr,
1758                                            invert_tree_comparison (c, false),
1759                                            gimple_assign_rhs1 (s),
1760                                            gimple_assign_rhs2 (s));
1761         }
1762     }
1763   return false;
1764 }
1765
1766 /* Check to see if two boolean expressions OP1 and OP2 are logically
1767    equivalent.  */
1768
1769 static bool
1770 same_bool_result_p (const_tree op1, const_tree op2)
1771 {
1772   /* Simple cases first.  */
1773   if (operand_equal_p (op1, op2, 0))
1774     return true;
1775
1776   /* Check the cases where at least one of the operands is a comparison.
1777      These are a bit smarter than operand_equal_p in that they apply some
1778      identifies on SSA_NAMEs.  */
1779   if (TREE_CODE_CLASS (TREE_CODE (op2)) == tcc_comparison
1780       && same_bool_comparison_p (op1, TREE_CODE (op2),
1781                                  TREE_OPERAND (op2, 0),
1782                                  TREE_OPERAND (op2, 1)))
1783     return true;
1784   if (TREE_CODE_CLASS (TREE_CODE (op1)) == tcc_comparison
1785       && same_bool_comparison_p (op2, TREE_CODE (op1),
1786                                  TREE_OPERAND (op1, 0),
1787                                  TREE_OPERAND (op1, 1)))
1788     return true;
1789
1790   /* Default case.  */
1791   return false;
1792 }
1793
1794 /* Forward declarations for some mutually recursive functions.  */
1795
1796 static tree
1797 and_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
1798                    enum tree_code code2, tree op2a, tree op2b);
1799 static tree
1800 and_var_with_comparison (tree var, bool invert,
1801                          enum tree_code code2, tree op2a, tree op2b);
1802 static tree
1803 and_var_with_comparison_1 (gimple stmt,
1804                            enum tree_code code2, tree op2a, tree op2b);
1805 static tree
1806 or_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
1807                   enum tree_code code2, tree op2a, tree op2b);
1808 static tree
1809 or_var_with_comparison (tree var, bool invert,
1810                         enum tree_code code2, tree op2a, tree op2b);
1811 static tree
1812 or_var_with_comparison_1 (gimple stmt,
1813                           enum tree_code code2, tree op2a, tree op2b);
1814
1815 /* Helper function for and_comparisons_1:  try to simplify the AND of the
1816    ssa variable VAR with the comparison specified by (OP2A CODE2 OP2B).
1817    If INVERT is true, invert the value of the VAR before doing the AND.
1818    Return NULL_EXPR if we can't simplify this to a single expression.  */
1819
1820 static tree
1821 and_var_with_comparison (tree var, bool invert,
1822                          enum tree_code code2, tree op2a, tree op2b)
1823 {
1824   tree t;
1825   gimple stmt = SSA_NAME_DEF_STMT (var);
1826
1827   /* We can only deal with variables whose definitions are assignments.  */
1828   if (!is_gimple_assign (stmt))
1829     return NULL_TREE;
1830
1831   /* If we have an inverted comparison, apply DeMorgan's law and rewrite
1832      !var AND (op2a code2 op2b) => !(var OR !(op2a code2 op2b))
1833      Then we only have to consider the simpler non-inverted cases.  */
1834   if (invert)
1835     t = or_var_with_comparison_1 (stmt,
1836                                   invert_tree_comparison (code2, false),
1837                                   op2a, op2b);
1838   else
1839     t = and_var_with_comparison_1 (stmt, code2, op2a, op2b);
1840   return canonicalize_bool (t, invert);
1841 }
1842
1843 /* Try to simplify the AND of the ssa variable defined by the assignment
1844    STMT with the comparison specified by (OP2A CODE2 OP2B).
1845    Return NULL_EXPR if we can't simplify this to a single expression.  */
1846
1847 static tree
1848 and_var_with_comparison_1 (gimple stmt,
1849                            enum tree_code code2, tree op2a, tree op2b)
1850 {
1851   tree var = gimple_assign_lhs (stmt);
1852   tree true_test_var = NULL_TREE;
1853   tree false_test_var = NULL_TREE;
1854   enum tree_code innercode = gimple_assign_rhs_code (stmt);
1855
1856   /* Check for identities like (var AND (var == 0)) => false.  */
1857   if (TREE_CODE (op2a) == SSA_NAME
1858       && TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE)
1859     {
1860       if ((code2 == NE_EXPR && integer_zerop (op2b))
1861           || (code2 == EQ_EXPR && integer_nonzerop (op2b)))
1862         {
1863           true_test_var = op2a;
1864           if (var == true_test_var)
1865             return var;
1866         }
1867       else if ((code2 == EQ_EXPR && integer_zerop (op2b))
1868                || (code2 == NE_EXPR && integer_nonzerop (op2b)))
1869         {
1870           false_test_var = op2a;
1871           if (var == false_test_var)
1872             return boolean_false_node;
1873         }
1874     }
1875
1876   /* If the definition is a comparison, recurse on it.  */
1877   if (TREE_CODE_CLASS (innercode) == tcc_comparison)
1878     {
1879       tree t = and_comparisons_1 (innercode,
1880                                   gimple_assign_rhs1 (stmt),
1881                                   gimple_assign_rhs2 (stmt),
1882                                   code2,
1883                                   op2a,
1884                                   op2b);
1885       if (t)
1886         return t;
1887     }
1888
1889   /* If the definition is an AND or OR expression, we may be able to
1890      simplify by reassociating.  */
1891   if (innercode == TRUTH_AND_EXPR
1892       || innercode == TRUTH_OR_EXPR
1893       || (TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE
1894           && (innercode == BIT_AND_EXPR || innercode == BIT_IOR_EXPR)))
1895     {
1896       tree inner1 = gimple_assign_rhs1 (stmt);
1897       tree inner2 = gimple_assign_rhs2 (stmt);
1898       gimple s;
1899       tree t;
1900       tree partial = NULL_TREE;
1901       bool is_and = (innercode == TRUTH_AND_EXPR || innercode == BIT_AND_EXPR);
1902
1903       /* Check for boolean identities that don't require recursive examination
1904          of inner1/inner2:
1905          inner1 AND (inner1 AND inner2) => inner1 AND inner2 => var
1906          inner1 AND (inner1 OR inner2) => inner1
1907          !inner1 AND (inner1 AND inner2) => false
1908          !inner1 AND (inner1 OR inner2) => !inner1 AND inner2
1909          Likewise for similar cases involving inner2.  */
1910       if (inner1 == true_test_var)
1911         return (is_and ? var : inner1);
1912       else if (inner2 == true_test_var)
1913         return (is_and ? var : inner2);
1914       else if (inner1 == false_test_var)
1915         return (is_and
1916                 ? boolean_false_node
1917                 : and_var_with_comparison (inner2, false, code2, op2a, op2b));
1918       else if (inner2 == false_test_var)
1919         return (is_and
1920                 ? boolean_false_node
1921                 : and_var_with_comparison (inner1, false, code2, op2a, op2b));
1922
1923       /* Next, redistribute/reassociate the AND across the inner tests.
1924          Compute the first partial result, (inner1 AND (op2a code op2b))  */
1925       if (TREE_CODE (inner1) == SSA_NAME
1926           && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner1))
1927           && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
1928           && (t = maybe_fold_and_comparisons (gimple_assign_rhs_code (s),
1929                                               gimple_assign_rhs1 (s),
1930                                               gimple_assign_rhs2 (s),
1931                                               code2, op2a, op2b)))
1932         {
1933           /* Handle the AND case, where we are reassociating:
1934              (inner1 AND inner2) AND (op2a code2 op2b)
1935              => (t AND inner2)
1936              If the partial result t is a constant, we win.  Otherwise
1937              continue on to try reassociating with the other inner test.  */
1938           if (is_and)
1939             {
1940               if (integer_onep (t))
1941                 return inner2;
1942               else if (integer_zerop (t))
1943                 return boolean_false_node;
1944             }
1945
1946           /* Handle the OR case, where we are redistributing:
1947              (inner1 OR inner2) AND (op2a code2 op2b)
1948              => (t OR (inner2 AND (op2a code2 op2b)))  */
1949           else if (integer_onep (t))
1950             return boolean_true_node;
1951
1952           /* Save partial result for later.  */
1953           partial = t;
1954         }
1955
1956       /* Compute the second partial result, (inner2 AND (op2a code op2b)) */
1957       if (TREE_CODE (inner2) == SSA_NAME
1958           && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner2))
1959           && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
1960           && (t = maybe_fold_and_comparisons (gimple_assign_rhs_code (s),
1961                                               gimple_assign_rhs1 (s),
1962                                               gimple_assign_rhs2 (s),
1963                                               code2, op2a, op2b)))
1964         {
1965           /* Handle the AND case, where we are reassociating:
1966              (inner1 AND inner2) AND (op2a code2 op2b)
1967              => (inner1 AND t)  */
1968           if (is_and)
1969             {
1970               if (integer_onep (t))
1971                 return inner1;
1972               else if (integer_zerop (t))
1973                 return boolean_false_node;
1974               /* If both are the same, we can apply the identity
1975                  (x AND x) == x.  */
1976               else if (partial && same_bool_result_p (t, partial))
1977                 return t;
1978             }
1979
1980           /* Handle the OR case. where we are redistributing:
1981              (inner1 OR inner2) AND (op2a code2 op2b)
1982              => (t OR (inner1 AND (op2a code2 op2b)))
1983              => (t OR partial)  */
1984           else
1985             {
1986               if (integer_onep (t))
1987                 return boolean_true_node;
1988               else if (partial)
1989                 {
1990                   /* We already got a simplification for the other
1991                      operand to the redistributed OR expression.  The
1992                      interesting case is when at least one is false.
1993                      Or, if both are the same, we can apply the identity
1994                      (x OR x) == x.  */
1995                   if (integer_zerop (partial))
1996                     return t;
1997                   else if (integer_zerop (t))
1998                     return partial;
1999                   else if (same_bool_result_p (t, partial))
2000                     return t;
2001                 }
2002             }
2003         }
2004     }
2005   return NULL_TREE;
2006 }
2007
2008 /* Try to simplify the AND of two comparisons defined by
2009    (OP1A CODE1 OP1B) and (OP2A CODE2 OP2B), respectively.
2010    If this can be done without constructing an intermediate value,
2011    return the resulting tree; otherwise NULL_TREE is returned.
2012    This function is deliberately asymmetric as it recurses on SSA_DEFs
2013    in the first comparison but not the second.  */
2014
2015 static tree
2016 and_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
2017                    enum tree_code code2, tree op2a, tree op2b)
2018 {
2019   /* First check for ((x CODE1 y) AND (x CODE2 y)).  */
2020   if (operand_equal_p (op1a, op2a, 0)
2021       && operand_equal_p (op1b, op2b, 0))
2022     {
2023       tree t = combine_comparisons (UNKNOWN_LOCATION,
2024                                     TRUTH_ANDIF_EXPR, code1, code2,
2025                                     boolean_type_node, op1a, op1b);
2026       if (t)
2027         return t;
2028     }
2029
2030   /* Likewise the swapped case of the above.  */
2031   if (operand_equal_p (op1a, op2b, 0)
2032       && operand_equal_p (op1b, op2a, 0))
2033     {
2034       tree t = combine_comparisons (UNKNOWN_LOCATION,
2035                                     TRUTH_ANDIF_EXPR, code1,
2036                                     swap_tree_comparison (code2),
2037                                     boolean_type_node, op1a, op1b);
2038       if (t)
2039         return t;
2040     }
2041
2042   /* If both comparisons are of the same value against constants, we might
2043      be able to merge them.  */
2044   if (operand_equal_p (op1a, op2a, 0)
2045       && TREE_CODE (op1b) == INTEGER_CST
2046       && TREE_CODE (op2b) == INTEGER_CST)
2047     {
2048       int cmp = tree_int_cst_compare (op1b, op2b);
2049
2050       /* If we have (op1a == op1b), we should either be able to
2051          return that or FALSE, depending on whether the constant op1b
2052          also satisfies the other comparison against op2b.  */
2053       if (code1 == EQ_EXPR)
2054         {
2055           bool done = true;
2056           bool val;
2057           switch (code2)
2058             {
2059             case EQ_EXPR: val = (cmp == 0); break;
2060             case NE_EXPR: val = (cmp != 0); break;
2061             case LT_EXPR: val = (cmp < 0); break;
2062             case GT_EXPR: val = (cmp > 0); break;
2063             case LE_EXPR: val = (cmp <= 0); break;
2064             case GE_EXPR: val = (cmp >= 0); break;
2065             default: done = false;
2066             }
2067           if (done)
2068             {
2069               if (val)
2070                 return fold_build2 (code1, boolean_type_node, op1a, op1b);
2071               else
2072                 return boolean_false_node;
2073             }
2074         }
2075       /* Likewise if the second comparison is an == comparison.  */
2076       else if (code2 == EQ_EXPR)
2077         {
2078           bool done = true;
2079           bool val;
2080           switch (code1)
2081             {
2082             case EQ_EXPR: val = (cmp == 0); break;
2083             case NE_EXPR: val = (cmp != 0); break;
2084             case LT_EXPR: val = (cmp > 0); break;
2085             case GT_EXPR: val = (cmp < 0); break;
2086             case LE_EXPR: val = (cmp >= 0); break;
2087             case GE_EXPR: val = (cmp <= 0); break;
2088             default: done = false;
2089             }
2090           if (done)
2091             {
2092               if (val)
2093                 return fold_build2 (code2, boolean_type_node, op2a, op2b);
2094               else
2095                 return boolean_false_node;
2096             }
2097         }
2098
2099       /* Same business with inequality tests.  */
2100       else if (code1 == NE_EXPR)
2101         {
2102           bool val;
2103           switch (code2)
2104             {
2105             case EQ_EXPR: val = (cmp != 0); break;
2106             case NE_EXPR: val = (cmp == 0); break;
2107             case LT_EXPR: val = (cmp >= 0); break;
2108             case GT_EXPR: val = (cmp <= 0); break;
2109             case LE_EXPR: val = (cmp > 0); break;
2110             case GE_EXPR: val = (cmp < 0); break;
2111             default:
2112               val = false;
2113             }
2114           if (val)
2115             return fold_build2 (code2, boolean_type_node, op2a, op2b);
2116         }
2117       else if (code2 == NE_EXPR)
2118         {
2119           bool val;
2120           switch (code1)
2121             {
2122             case EQ_EXPR: val = (cmp == 0); break;
2123             case NE_EXPR: val = (cmp != 0); break;
2124             case LT_EXPR: val = (cmp <= 0); break;
2125             case GT_EXPR: val = (cmp >= 0); break;
2126             case LE_EXPR: val = (cmp < 0); break;
2127             case GE_EXPR: val = (cmp > 0); break;
2128             default:
2129               val = false;
2130             }
2131           if (val)
2132             return fold_build2 (code1, boolean_type_node, op1a, op1b);
2133         }
2134
2135       /* Chose the more restrictive of two < or <= comparisons.  */
2136       else if ((code1 == LT_EXPR || code1 == LE_EXPR)
2137                && (code2 == LT_EXPR || code2 == LE_EXPR))
2138         {
2139           if ((cmp < 0) || (cmp == 0 && code1 == LT_EXPR))
2140             return fold_build2 (code1, boolean_type_node, op1a, op1b);
2141           else
2142             return fold_build2 (code2, boolean_type_node, op2a, op2b);
2143         }
2144
2145       /* Likewise chose the more restrictive of two > or >= comparisons.  */
2146       else if ((code1 == GT_EXPR || code1 == GE_EXPR)
2147                && (code2 == GT_EXPR || code2 == GE_EXPR))
2148         {
2149           if ((cmp > 0) || (cmp == 0 && code1 == GT_EXPR))
2150             return fold_build2 (code1, boolean_type_node, op1a, op1b);
2151           else
2152             return fold_build2 (code2, boolean_type_node, op2a, op2b);
2153         }
2154
2155       /* Check for singleton ranges.  */
2156       else if (cmp == 0
2157                && ((code1 == LE_EXPR && code2 == GE_EXPR)
2158                    || (code1 == GE_EXPR && code2 == LE_EXPR)))
2159         return fold_build2 (EQ_EXPR, boolean_type_node, op1a, op2b);
2160
2161       /* Check for disjoint ranges. */
2162       else if (cmp <= 0
2163                && (code1 == LT_EXPR || code1 == LE_EXPR)
2164                && (code2 == GT_EXPR || code2 == GE_EXPR))
2165         return boolean_false_node;
2166       else if (cmp >= 0
2167                && (code1 == GT_EXPR || code1 == GE_EXPR)
2168                && (code2 == LT_EXPR || code2 == LE_EXPR))
2169         return boolean_false_node;
2170     }
2171
2172   /* Perhaps the first comparison is (NAME != 0) or (NAME == 1) where
2173      NAME's definition is a truth value.  See if there are any simplifications
2174      that can be done against the NAME's definition.  */
2175   if (TREE_CODE (op1a) == SSA_NAME
2176       && (code1 == NE_EXPR || code1 == EQ_EXPR)
2177       && (integer_zerop (op1b) || integer_onep (op1b)))
2178     {
2179       bool invert = ((code1 == EQ_EXPR && integer_zerop (op1b))
2180                      || (code1 == NE_EXPR && integer_onep (op1b)));
2181       gimple stmt = SSA_NAME_DEF_STMT (op1a);
2182       switch (gimple_code (stmt))
2183         {
2184         case GIMPLE_ASSIGN:
2185           /* Try to simplify by copy-propagating the definition.  */
2186           return and_var_with_comparison (op1a, invert, code2, op2a, op2b);
2187
2188         case GIMPLE_PHI:
2189           /* If every argument to the PHI produces the same result when
2190              ANDed with the second comparison, we win.
2191              Do not do this unless the type is bool since we need a bool
2192              result here anyway.  */
2193           if (TREE_CODE (TREE_TYPE (op1a)) == BOOLEAN_TYPE)
2194             {
2195               tree result = NULL_TREE;
2196               unsigned i;
2197               for (i = 0; i < gimple_phi_num_args (stmt); i++)
2198                 {
2199                   tree arg = gimple_phi_arg_def (stmt, i);
2200
2201                   /* If this PHI has itself as an argument, ignore it.
2202                      If all the other args produce the same result,
2203                      we're still OK.  */
2204                   if (arg == gimple_phi_result (stmt))
2205                     continue;
2206                   else if (TREE_CODE (arg) == INTEGER_CST)
2207                     {
2208                       if (invert ? integer_nonzerop (arg) : integer_zerop (arg))
2209                         {
2210                           if (!result)
2211                             result = boolean_false_node;
2212                           else if (!integer_zerop (result))
2213                             return NULL_TREE;
2214                         }
2215                       else if (!result)
2216                         result = fold_build2 (code2, boolean_type_node,
2217                                               op2a, op2b);
2218                       else if (!same_bool_comparison_p (result,
2219                                                         code2, op2a, op2b))
2220                         return NULL_TREE;
2221                     }
2222                   else if (TREE_CODE (arg) == SSA_NAME
2223                            && !SSA_NAME_IS_DEFAULT_DEF (arg))
2224                     {
2225                       tree temp;
2226                       gimple def_stmt = SSA_NAME_DEF_STMT (arg);
2227                       /* In simple cases we can look through PHI nodes,
2228                          but we have to be careful with loops.
2229                          See PR49073.  */
2230                       if (! dom_info_available_p (CDI_DOMINATORS)
2231                           || gimple_bb (def_stmt) == gimple_bb (stmt)
2232                           || dominated_by_p (CDI_DOMINATORS,
2233                                              gimple_bb (def_stmt),
2234                                              gimple_bb (stmt)))
2235                         return NULL_TREE;
2236                       temp = and_var_with_comparison (arg, invert, code2,
2237                                                       op2a, op2b);
2238                       if (!temp)
2239                         return NULL_TREE;
2240                       else if (!result)
2241                         result = temp;
2242                       else if (!same_bool_result_p (result, temp))
2243                         return NULL_TREE;
2244                     }
2245                   else
2246                     return NULL_TREE;
2247                 }
2248               return result;
2249             }
2250
2251         default:
2252           break;
2253         }
2254     }
2255   return NULL_TREE;
2256 }
2257
2258 /* Try to simplify the AND of two comparisons, specified by
2259    (OP1A CODE1 OP1B) and (OP2B CODE2 OP2B), respectively.
2260    If this can be simplified to a single expression (without requiring
2261    introducing more SSA variables to hold intermediate values),
2262    return the resulting tree.  Otherwise return NULL_TREE.
2263    If the result expression is non-null, it has boolean type.  */
2264
2265 tree
2266 maybe_fold_and_comparisons (enum tree_code code1, tree op1a, tree op1b,
2267                             enum tree_code code2, tree op2a, tree op2b)
2268 {
2269   tree t = and_comparisons_1 (code1, op1a, op1b, code2, op2a, op2b);
2270   if (t)
2271     return t;
2272   else
2273     return and_comparisons_1 (code2, op2a, op2b, code1, op1a, op1b);
2274 }
2275
2276 /* Helper function for or_comparisons_1:  try to simplify the OR of the
2277    ssa variable VAR with the comparison specified by (OP2A CODE2 OP2B).
2278    If INVERT is true, invert the value of VAR before doing the OR.
2279    Return NULL_EXPR if we can't simplify this to a single expression.  */
2280
2281 static tree
2282 or_var_with_comparison (tree var, bool invert,
2283                         enum tree_code code2, tree op2a, tree op2b)
2284 {
2285   tree t;
2286   gimple stmt = SSA_NAME_DEF_STMT (var);
2287
2288   /* We can only deal with variables whose definitions are assignments.  */
2289   if (!is_gimple_assign (stmt))
2290     return NULL_TREE;
2291
2292   /* If we have an inverted comparison, apply DeMorgan's law and rewrite
2293      !var OR (op2a code2 op2b) => !(var AND !(op2a code2 op2b))
2294      Then we only have to consider the simpler non-inverted cases.  */
2295   if (invert)
2296     t = and_var_with_comparison_1 (stmt,
2297                                    invert_tree_comparison (code2, false),
2298                                    op2a, op2b);
2299   else
2300     t = or_var_with_comparison_1 (stmt, code2, op2a, op2b);
2301   return canonicalize_bool (t, invert);
2302 }
2303
2304 /* Try to simplify the OR of the ssa variable defined by the assignment
2305    STMT with the comparison specified by (OP2A CODE2 OP2B).
2306    Return NULL_EXPR if we can't simplify this to a single expression.  */
2307
2308 static tree
2309 or_var_with_comparison_1 (gimple stmt,
2310                           enum tree_code code2, tree op2a, tree op2b)
2311 {
2312   tree var = gimple_assign_lhs (stmt);
2313   tree true_test_var = NULL_TREE;
2314   tree false_test_var = NULL_TREE;
2315   enum tree_code innercode = gimple_assign_rhs_code (stmt);
2316
2317   /* Check for identities like (var OR (var != 0)) => true .  */
2318   if (TREE_CODE (op2a) == SSA_NAME
2319       && TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE)
2320     {
2321       if ((code2 == NE_EXPR && integer_zerop (op2b))
2322           || (code2 == EQ_EXPR && integer_nonzerop (op2b)))
2323         {
2324           true_test_var = op2a;
2325           if (var == true_test_var)
2326             return var;
2327         }
2328       else if ((code2 == EQ_EXPR && integer_zerop (op2b))
2329                || (code2 == NE_EXPR && integer_nonzerop (op2b)))
2330         {
2331           false_test_var = op2a;
2332           if (var == false_test_var)
2333             return boolean_true_node;
2334         }
2335     }
2336
2337   /* If the definition is a comparison, recurse on it.  */
2338   if (TREE_CODE_CLASS (innercode) == tcc_comparison)
2339     {
2340       tree t = or_comparisons_1 (innercode,
2341                                  gimple_assign_rhs1 (stmt),
2342                                  gimple_assign_rhs2 (stmt),
2343                                  code2,
2344                                  op2a,
2345                                  op2b);
2346       if (t)
2347         return t;
2348     }
2349
2350   /* If the definition is an AND or OR expression, we may be able to
2351      simplify by reassociating.  */
2352   if (innercode == TRUTH_AND_EXPR
2353       || innercode == TRUTH_OR_EXPR
2354       || (TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE
2355           && (innercode == BIT_AND_EXPR || innercode == BIT_IOR_EXPR)))
2356     {
2357       tree inner1 = gimple_assign_rhs1 (stmt);
2358       tree inner2 = gimple_assign_rhs2 (stmt);
2359       gimple s;
2360       tree t;
2361       tree partial = NULL_TREE;
2362       bool is_or = (innercode == TRUTH_OR_EXPR || innercode == BIT_IOR_EXPR);
2363
2364       /* Check for boolean identities that don't require recursive examination
2365          of inner1/inner2:
2366          inner1 OR (inner1 OR inner2) => inner1 OR inner2 => var
2367          inner1 OR (inner1 AND inner2) => inner1
2368          !inner1 OR (inner1 OR inner2) => true
2369          !inner1 OR (inner1 AND inner2) => !inner1 OR inner2
2370       */
2371       if (inner1 == true_test_var)
2372         return (is_or ? var : inner1);
2373       else if (inner2 == true_test_var)
2374         return (is_or ? var : inner2);
2375       else if (inner1 == false_test_var)
2376         return (is_or
2377                 ? boolean_true_node
2378                 : or_var_with_comparison (inner2, false, code2, op2a, op2b));
2379       else if (inner2 == false_test_var)
2380         return (is_or
2381                 ? boolean_true_node
2382                 : or_var_with_comparison (inner1, false, code2, op2a, op2b));
2383
2384       /* Next, redistribute/reassociate the OR across the inner tests.
2385          Compute the first partial result, (inner1 OR (op2a code op2b))  */
2386       if (TREE_CODE (inner1) == SSA_NAME
2387           && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner1))
2388           && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
2389           && (t = maybe_fold_or_comparisons (gimple_assign_rhs_code (s),
2390                                              gimple_assign_rhs1 (s),
2391                                              gimple_assign_rhs2 (s),
2392                                              code2, op2a, op2b)))
2393         {
2394           /* Handle the OR case, where we are reassociating:
2395              (inner1 OR inner2) OR (op2a code2 op2b)
2396              => (t OR inner2)
2397              If the partial result t is a constant, we win.  Otherwise
2398              continue on to try reassociating with the other inner test.  */
2399           if (is_or)
2400             {
2401               if (integer_onep (t))
2402                 return boolean_true_node;
2403               else if (integer_zerop (t))
2404                 return inner2;
2405             }
2406
2407           /* Handle the AND case, where we are redistributing:
2408              (inner1 AND inner2) OR (op2a code2 op2b)
2409              => (t AND (inner2 OR (op2a code op2b)))  */
2410           else if (integer_zerop (t))
2411             return boolean_false_node;
2412
2413           /* Save partial result for later.  */
2414           partial = t;
2415         }
2416
2417       /* Compute the second partial result, (inner2 OR (op2a code op2b)) */
2418       if (TREE_CODE (inner2) == SSA_NAME
2419           && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner2))
2420           && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
2421           && (t = maybe_fold_or_comparisons (gimple_assign_rhs_code (s),
2422                                              gimple_assign_rhs1 (s),
2423                                              gimple_assign_rhs2 (s),
2424                                              code2, op2a, op2b)))
2425         {
2426           /* Handle the OR case, where we are reassociating:
2427              (inner1 OR inner2) OR (op2a code2 op2b)
2428              => (inner1 OR t)
2429              => (t OR partial)  */
2430           if (is_or)
2431             {
2432               if (integer_zerop (t))
2433                 return inner1;
2434               else if (integer_onep (t))
2435                 return boolean_true_node;
2436               /* If both are the same, we can apply the identity
2437                  (x OR x) == x.  */
2438               else if (partial && same_bool_result_p (t, partial))
2439                 return t;
2440             }
2441
2442           /* Handle the AND case, where we are redistributing:
2443              (inner1 AND inner2) OR (op2a code2 op2b)
2444              => (t AND (inner1 OR (op2a code2 op2b)))
2445              => (t AND partial)  */
2446           else
2447             {
2448               if (integer_zerop (t))
2449                 return boolean_false_node;
2450               else if (partial)
2451                 {
2452                   /* We already got a simplification for the other
2453                      operand to the redistributed AND expression.  The
2454                      interesting case is when at least one is true.
2455                      Or, if both are the same, we can apply the identity
2456                      (x AND x) == x.  */
2457                   if (integer_onep (partial))
2458                     return t;
2459                   else if (integer_onep (t))
2460                     return partial;
2461                   else if (same_bool_result_p (t, partial))
2462                     return t;
2463                 }
2464             }
2465         }
2466     }
2467   return NULL_TREE;
2468 }
2469
2470 /* Try to simplify the OR of two comparisons defined by
2471    (OP1A CODE1 OP1B) and (OP2A CODE2 OP2B), respectively.
2472    If this can be done without constructing an intermediate value,
2473    return the resulting tree; otherwise NULL_TREE is returned.
2474    This function is deliberately asymmetric as it recurses on SSA_DEFs
2475    in the first comparison but not the second.  */
2476
2477 static tree
2478 or_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
2479                   enum tree_code code2, tree op2a, tree op2b)
2480 {
2481   /* First check for ((x CODE1 y) OR (x CODE2 y)).  */
2482   if (operand_equal_p (op1a, op2a, 0)
2483       && operand_equal_p (op1b, op2b, 0))
2484     {
2485       tree t = combine_comparisons (UNKNOWN_LOCATION,
2486                                     TRUTH_ORIF_EXPR, code1, code2,
2487                                     boolean_type_node, op1a, op1b);
2488       if (t)
2489         return t;
2490     }
2491
2492   /* Likewise the swapped case of the above.  */
2493   if (operand_equal_p (op1a, op2b, 0)
2494       && operand_equal_p (op1b, op2a, 0))
2495     {
2496       tree t = combine_comparisons (UNKNOWN_LOCATION,
2497                                     TRUTH_ORIF_EXPR, code1,
2498                                     swap_tree_comparison (code2),
2499                                     boolean_type_node, op1a, op1b);
2500       if (t)
2501         return t;
2502     }
2503
2504   /* If both comparisons are of the same value against constants, we might
2505      be able to merge them.  */
2506   if (operand_equal_p (op1a, op2a, 0)
2507       && TREE_CODE (op1b) == INTEGER_CST
2508       && TREE_CODE (op2b) == INTEGER_CST)
2509     {
2510       int cmp = tree_int_cst_compare (op1b, op2b);
2511
2512       /* If we have (op1a != op1b), we should either be able to
2513          return that or TRUE, depending on whether the constant op1b
2514          also satisfies the other comparison against op2b.  */
2515       if (code1 == NE_EXPR)
2516         {
2517           bool done = true;
2518           bool val;
2519           switch (code2)
2520             {
2521             case EQ_EXPR: val = (cmp == 0); break;
2522             case NE_EXPR: val = (cmp != 0); break;
2523             case LT_EXPR: val = (cmp < 0); break;
2524             case GT_EXPR: val = (cmp > 0); break;
2525             case LE_EXPR: val = (cmp <= 0); break;
2526             case GE_EXPR: val = (cmp >= 0); break;
2527             default: done = false;
2528             }
2529           if (done)
2530             {
2531               if (val)
2532                 return boolean_true_node;
2533               else
2534                 return fold_build2 (code1, boolean_type_node, op1a, op1b);
2535             }
2536         }
2537       /* Likewise if the second comparison is a != comparison.  */
2538       else if (code2 == NE_EXPR)
2539         {
2540           bool done = true;
2541           bool val;
2542           switch (code1)
2543             {
2544             case EQ_EXPR: val = (cmp == 0); break;
2545             case NE_EXPR: val = (cmp != 0); break;
2546             case LT_EXPR: val = (cmp > 0); break;
2547             case GT_EXPR: val = (cmp < 0); break;
2548             case LE_EXPR: val = (cmp >= 0); break;
2549             case GE_EXPR: val = (cmp <= 0); break;
2550             default: done = false;
2551             }
2552           if (done)
2553             {
2554               if (val)
2555                 return boolean_true_node;
2556               else
2557                 return fold_build2 (code2, boolean_type_node, op2a, op2b);
2558             }
2559         }
2560
2561       /* See if an equality test is redundant with the other comparison.  */
2562       else if (code1 == EQ_EXPR)
2563         {
2564           bool val;
2565           switch (code2)
2566             {
2567             case EQ_EXPR: val = (cmp == 0); break;
2568             case NE_EXPR: val = (cmp != 0); break;
2569             case LT_EXPR: val = (cmp < 0); break;
2570             case GT_EXPR: val = (cmp > 0); break;
2571             case LE_EXPR: val = (cmp <= 0); break;
2572             case GE_EXPR: val = (cmp >= 0); break;
2573             default:
2574               val = false;
2575             }
2576           if (val)
2577             return fold_build2 (code2, boolean_type_node, op2a, op2b);
2578         }
2579       else if (code2 == EQ_EXPR)
2580         {
2581           bool val;
2582           switch (code1)
2583             {
2584             case EQ_EXPR: val = (cmp == 0); break;
2585             case NE_EXPR: val = (cmp != 0); break;
2586             case LT_EXPR: val = (cmp > 0); break;
2587             case GT_EXPR: val = (cmp < 0); break;
2588             case LE_EXPR: val = (cmp >= 0); break;
2589             case GE_EXPR: val = (cmp <= 0); break;
2590             default:
2591               val = false;
2592             }
2593           if (val)
2594             return fold_build2 (code1, boolean_type_node, op1a, op1b);
2595         }
2596
2597       /* Chose the less restrictive of two < or <= comparisons.  */
2598       else if ((code1 == LT_EXPR || code1 == LE_EXPR)
2599                && (code2 == LT_EXPR || code2 == LE_EXPR))
2600         {
2601           if ((cmp < 0) || (cmp == 0 && code1 == LT_EXPR))
2602             return fold_build2 (code2, boolean_type_node, op2a, op2b);
2603           else
2604             return fold_build2 (code1, boolean_type_node, op1a, op1b);
2605         }
2606
2607       /* Likewise chose the less restrictive of two > or >= comparisons.  */
2608       else if ((code1 == GT_EXPR || code1 == GE_EXPR)
2609                && (code2 == GT_EXPR || code2 == GE_EXPR))
2610         {
2611           if ((cmp > 0) || (cmp == 0 && code1 == GT_EXPR))
2612             return fold_build2 (code2, boolean_type_node, op2a, op2b);
2613           else
2614             return fold_build2 (code1, boolean_type_node, op1a, op1b);
2615         }
2616
2617       /* Check for singleton ranges.  */
2618       else if (cmp == 0
2619                && ((code1 == LT_EXPR && code2 == GT_EXPR)
2620                    || (code1 == GT_EXPR && code2 == LT_EXPR)))
2621         return fold_build2 (NE_EXPR, boolean_type_node, op1a, op2b);
2622
2623       /* Check for less/greater pairs that don't restrict the range at all.  */
2624       else if (cmp >= 0
2625                && (code1 == LT_EXPR || code1 == LE_EXPR)
2626                && (code2 == GT_EXPR || code2 == GE_EXPR))
2627         return boolean_true_node;
2628       else if (cmp <= 0
2629                && (code1 == GT_EXPR || code1 == GE_EXPR)
2630                && (code2 == LT_EXPR || code2 == LE_EXPR))
2631         return boolean_true_node;
2632     }
2633
2634   /* Perhaps the first comparison is (NAME != 0) or (NAME == 1) where
2635      NAME's definition is a truth value.  See if there are any simplifications
2636      that can be done against the NAME's definition.  */
2637   if (TREE_CODE (op1a) == SSA_NAME
2638       && (code1 == NE_EXPR || code1 == EQ_EXPR)
2639       && (integer_zerop (op1b) || integer_onep (op1b)))
2640     {
2641       bool invert = ((code1 == EQ_EXPR && integer_zerop (op1b))
2642                      || (code1 == NE_EXPR && integer_onep (op1b)));
2643       gimple stmt = SSA_NAME_DEF_STMT (op1a);
2644       switch (gimple_code (stmt))
2645         {
2646         case GIMPLE_ASSIGN:
2647           /* Try to simplify by copy-propagating the definition.  */
2648           return or_var_with_comparison (op1a, invert, code2, op2a, op2b);
2649
2650         case GIMPLE_PHI:
2651           /* If every argument to the PHI produces the same result when
2652              ORed with the second comparison, we win.
2653              Do not do this unless the type is bool since we need a bool
2654              result here anyway.  */
2655           if (TREE_CODE (TREE_TYPE (op1a)) == BOOLEAN_TYPE)
2656             {
2657               tree result = NULL_TREE;
2658               unsigned i;
2659               for (i = 0; i < gimple_phi_num_args (stmt); i++)
2660                 {
2661                   tree arg = gimple_phi_arg_def (stmt, i);
2662
2663                   /* If this PHI has itself as an argument, ignore it.
2664                      If all the other args produce the same result,
2665                      we're still OK.  */
2666                   if (arg == gimple_phi_result (stmt))
2667                     continue;
2668                   else if (TREE_CODE (arg) == INTEGER_CST)
2669                     {
2670                       if (invert ? integer_zerop (arg) : integer_nonzerop (arg))
2671                         {
2672                           if (!result)
2673                             result = boolean_true_node;
2674                           else if (!integer_onep (result))
2675                             return NULL_TREE;
2676                         }
2677                       else if (!result)
2678                         result = fold_build2 (code2, boolean_type_node,
2679                                               op2a, op2b);
2680                       else if (!same_bool_comparison_p (result,
2681                                                         code2, op2a, op2b))
2682                         return NULL_TREE;
2683                     }
2684                   else if (TREE_CODE (arg) == SSA_NAME
2685                            && !SSA_NAME_IS_DEFAULT_DEF (arg))
2686                     {
2687                       tree temp;
2688                       gimple def_stmt = SSA_NAME_DEF_STMT (arg);
2689                       /* In simple cases we can look through PHI nodes,
2690                          but we have to be careful with loops.
2691                          See PR49073.  */
2692                       if (! dom_info_available_p (CDI_DOMINATORS)
2693                           || gimple_bb (def_stmt) == gimple_bb (stmt)
2694                           || dominated_by_p (CDI_DOMINATORS,
2695                                              gimple_bb (def_stmt),
2696                                              gimple_bb (stmt)))
2697                         return NULL_TREE;
2698                       temp = or_var_with_comparison (arg, invert, code2,
2699                                                      op2a, op2b);
2700                       if (!temp)
2701                         return NULL_TREE;
2702                       else if (!result)
2703                         result = temp;
2704                       else if (!same_bool_result_p (result, temp))
2705                         return NULL_TREE;
2706                     }
2707                   else
2708                     return NULL_TREE;
2709                 }
2710               return result;
2711             }
2712
2713         default:
2714           break;
2715         }
2716     }
2717   return NULL_TREE;
2718 }
2719
2720 /* Try to simplify the OR of two comparisons, specified by
2721    (OP1A CODE1 OP1B) and (OP2B CODE2 OP2B), respectively.
2722    If this can be simplified to a single expression (without requiring
2723    introducing more SSA variables to hold intermediate values),
2724    return the resulting tree.  Otherwise return NULL_TREE.
2725    If the result expression is non-null, it has boolean type.  */
2726
2727 tree
2728 maybe_fold_or_comparisons (enum tree_code code1, tree op1a, tree op1b,
2729                            enum tree_code code2, tree op2a, tree op2b)
2730 {
2731   tree t = or_comparisons_1 (code1, op1a, op1b, code2, op2a, op2b);
2732   if (t)
2733     return t;
2734   else
2735     return or_comparisons_1 (code2, op2a, op2b, code1, op1a, op1b);
2736 }