gcc/tree-vect-transform.c

   1 /* Transformation Utilities for Loop Vectorization.
   2    Copyright (C) 2003,2004,2005 Free Software Foundation, Inc.
   3    Contributed by Dorit Naishlos <dorit@il.ibm.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 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 COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "ggc.h"
  27 #include "tree.h"
  28 #include "target.h"
  29 #include "rtl.h"
  30 #include "basic-block.h"
  31 #include "diagnostic.h"
  32 #include "tree-flow.h"
  33 #include "tree-dump.h"
  34 #include "timevar.h"
  35 #include "cfgloop.h"
  36 #include "expr.h"
  37 #include "optabs.h"
  38 #include "tree-data-ref.h"
  39 #include "tree-chrec.h"
  40 #include "tree-scalar-evolution.h"
  41 #include "tree-vectorizer.h"
  42 #include "langhooks.h"
  43 #include "tree-pass.h"
  44 #include "toplev.h"
  45 #include "real.h"
  46
  47 /* Utility functions for the code transformation.  */
  48 static bool vect_transform_stmt (tree, block_stmt_iterator *);
  49 static void vect_align_data_ref (tree);
  50 static tree vect_create_destination_var (tree, tree);
  51 static tree vect_create_data_ref_ptr
  52   (tree, block_stmt_iterator *, tree, tree *, bool);
  53 static tree vect_create_index_for_vector_ref (loop_vec_info);
  54 static tree vect_create_addr_base_for_vector_ref (tree, tree *, tree);
  55 static tree vect_get_new_vect_var (tree, enum vect_var_kind, const char *);
  56 static tree vect_get_vec_def_for_operand (tree, tree, tree *);
  57 static tree vect_init_vector (tree, tree);
  58 static void vect_finish_stmt_generation
  59   (tree stmt, tree vec_stmt, block_stmt_iterator *bsi);
  60 static bool vect_is_simple_cond (tree, loop_vec_info);
  61 static void update_vuses_to_preheader (tree, struct loop*);
  62 static tree get_initial_def_for_reduction (tree, tree, tree *);
  63
  64 /* Utility function dealing with loop peeling (not peeling itself).  */
  65 static void vect_generate_tmps_on_preheader
  66   (loop_vec_info, tree *, tree *, tree *);
  67 static tree vect_build_loop_niters (loop_vec_info);
  68 static void vect_update_ivs_after_vectorizer (loop_vec_info, tree, edge);
  69 static tree vect_gen_niters_for_prolog_loop (loop_vec_info, tree);
  70 static void vect_update_init_of_dr (struct data_reference *, tree niters);
  71 static void vect_update_inits_of_drs (loop_vec_info, tree);
  72 static void vect_do_peeling_for_alignment (loop_vec_info, struct loops *);
  73 static void vect_do_peeling_for_loop_bound
  74   (loop_vec_info, tree *, struct loops *);
  75
  76
  77 /* Function vect_get_new_vect_var.
  78
  79    Returns a name for a new variable. The current naming scheme appends the
  80    prefix "vect_" or "vect_p" (depending on the value of VAR_KIND) to
  81    the name of vectorizer generated variables, and appends that to NAME if
  82    provided.  */
  83
  84 static tree
  85 vect_get_new_vect_var (tree type, enum vect_var_kind var_kind, const char *name)
  86 {
  87   const char *prefix;
  88   tree new_vect_var;
  89
  90   switch (var_kind)
  91   {
  92   case vect_simple_var:
  93     prefix = "vect_";
  94     break;
  95   case vect_scalar_var:
  96     prefix = "stmp_";
  97     break;
  98   case vect_pointer_var:
  99     prefix = "vect_p";
 100     break;
 101   default:
 102     gcc_unreachable ();
 103   }
 104
 105   if (name)
 106     new_vect_var = create_tmp_var (type, concat (prefix, name, NULL));
 107   else
 108     new_vect_var = create_tmp_var (type, prefix);
 109
 110   return new_vect_var;
 111 }
 112
 113
 114 /* Function vect_create_index_for_vector_ref.
 115
 116    Create (and return) an index variable, along with it's update chain in the
 117    loop. This variable will be used to access a memory location in a vector
 118    operation.
 119
 120    Input:
 121    LOOP: The loop being vectorized.
 122    BSI: The block_stmt_iterator where STMT is. Any new stmts created by this
 123         function can be added here, or in the loop pre-header.
 124
 125    Output:
 126    Return an index that will be used to index a vector array.  It is expected
 127    that a pointer to the first vector will be used as the base address for the
 128    indexed reference.
 129
 130    FORNOW: we are not trying to be efficient, just creating a new index each
 131    time from scratch.  At this time all vector references could use the same
 132    index.
 133
 134    TODO: create only one index to be used by all vector references.  Record
 135    the index in the LOOP_VINFO the first time this procedure is called and
 136    return it on subsequent calls.  The increment of this index must be placed
 137    just before the conditional expression that ends the single block loop.  */
 138
 139 static tree
 140 vect_create_index_for_vector_ref (loop_vec_info loop_vinfo)
 141 {
 142   tree init, step;
 143   block_stmt_iterator incr_bsi;
 144   bool insert_after;
 145   tree indx_before_incr, indx_after_incr;
 146   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
 147   tree incr;
 148
 149   /* It is assumed that the base pointer used for vectorized access contains
 150      the address of the first vector.  Therefore the index used for vectorized
 151      access must be initialized to zero and incremented by 1.  */
 152
 153   init = integer_zero_node;
 154   step = integer_one_node;
 155
 156   standard_iv_increment_position (loop, &incr_bsi, &insert_after);
 157   create_iv (init, step, NULL_TREE, loop, &incr_bsi, insert_after,
 158         &indx_before_incr, &indx_after_incr);
 159   incr = bsi_stmt (incr_bsi);
 160   set_stmt_info ((tree_ann_t)stmt_ann (incr), new_stmt_vec_info (incr, loop_vinfo));
 161
 162   return indx_before_incr;
 163 }
 164
 165
 166 /* Function vect_create_addr_base_for_vector_ref.
 167
 168    Create an expression that computes the address of the first memory location
 169    that will be accessed for a data reference.
 170
 171    Input:
 172    STMT: The statement containing the data reference.
 173    NEW_STMT_LIST: Must be initialized to NULL_TREE or a statement list.
 174    OFFSET: Optional. If supplied, it is be added to the initial address.
 175
 176    Output:
 177    1. Return an SSA_NAME whose value is the address of the memory location of
 178       the first vector of the data reference.
 179    2. If new_stmt_list is not NULL_TREE after return then the caller must insert
 180       these statement(s) which define the returned SSA_NAME.
 181
 182    FORNOW: We are only handling array accesses with step 1.  */
 183
 184 static tree
 185 vect_create_addr_base_for_vector_ref (tree stmt,
 186                                       tree *new_stmt_list,
 187                                       tree offset)
 188 {
 189   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
 190   struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
 191   tree data_ref_base =
 192     unshare_expr (STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info));
 193   tree base_name = build_fold_indirect_ref (data_ref_base);
 194   tree ref = DR_REF (dr);
 195   tree scalar_type = TREE_TYPE (ref);
 196   tree scalar_ptr_type = build_pointer_type (scalar_type);
 197   tree vec_stmt;
 198   tree new_temp;
 199   tree addr_base, addr_expr;
 200   tree dest, new_stmt;
 201   tree base_offset = unshare_expr (STMT_VINFO_VECT_INIT_OFFSET (stmt_info));
 202
 203   /* Create base_offset */
 204   dest = create_tmp_var (TREE_TYPE (base_offset), "base_off");
 205   add_referenced_tmp_var (dest);
 206   base_offset = force_gimple_operand (base_offset, &new_stmt, false, dest);
 207   append_to_statement_list_force (new_stmt, new_stmt_list);
 208
 209   if (offset)
 210     {
 211       tree tmp = create_tmp_var (TREE_TYPE (base_offset), "offset");
 212       add_referenced_tmp_var (tmp);
 213       offset = fold (build2 (MULT_EXPR, TREE_TYPE (offset), offset,
 214                              STMT_VINFO_VECT_STEP (stmt_info)));
 215       base_offset = fold (build2 (PLUS_EXPR, TREE_TYPE (base_offset),
 216                                   base_offset, offset));
 217       base_offset = force_gimple_operand (base_offset, &new_stmt, false, tmp);
 218       append_to_statement_list_force (new_stmt, new_stmt_list);
 219     }
 220
 221   /* base + base_offset */
 222   addr_base = fold (build2 (PLUS_EXPR, TREE_TYPE (data_ref_base), data_ref_base,
 223                             base_offset));
 224
 225   /* addr_expr = addr_base */
 226   addr_expr = vect_get_new_vect_var (scalar_ptr_type, vect_pointer_var,
 227                                      get_name (base_name));
 228   add_referenced_tmp_var (addr_expr);
 229   vec_stmt = build2 (MODIFY_EXPR, void_type_node, addr_expr, addr_base);
 230   new_temp = make_ssa_name (addr_expr, vec_stmt);
 231   TREE_OPERAND (vec_stmt, 0) = new_temp;
 232   append_to_statement_list_force (vec_stmt, new_stmt_list);
 233
 234   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 235     {
 236       fprintf (vect_dump, "created ");
 237       print_generic_expr (vect_dump, vec_stmt, TDF_SLIM);
 238     }
 239   return new_temp;
 240 }
 241
 242
 243 /* Function vect_align_data_ref.
 244
 245    Handle misalignment of a memory accesses.
 246
 247    FORNOW: Can't handle misaligned accesses.
 248    Make sure that the dataref is aligned.  */
 249
 250 static void
 251 vect_align_data_ref (tree stmt)
 252 {
 253   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
 254   struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
 255
 256   /* FORNOW: can't handle misaligned accesses;
 257              all accesses expected to be aligned.  */
 258   gcc_assert (aligned_access_p (dr));
 259 }
 260
 261
 262 /* Function vect_create_data_ref_ptr.
 263
 264    Create a memory reference expression for vector access, to be used in a
 265    vector load/store stmt. The reference is based on a new pointer to vector
 266    type (vp).
 267
 268    Input:
 269    1. STMT: a stmt that references memory. Expected to be of the form
 270          MODIFY_EXPR <name, data-ref> or MODIFY_EXPR <data-ref, name>.
 271    2. BSI: block_stmt_iterator where new stmts can be added.
 272    3. OFFSET (optional): an offset to be added to the initial address accessed
 273         by the data-ref in STMT.
 274    4. ONLY_INIT: indicate if vp is to be updated in the loop, or remain
 275         pointing to the initial address.
 276
 277    Output:
 278    1. Declare a new ptr to vector_type, and have it point to the base of the
 279       data reference (initial addressed accessed by the data reference).
 280       For example, for vector of type V8HI, the following code is generated:
 281
 282       v8hi *vp;
 283       vp = (v8hi *)initial_address;
 284
 285       if OFFSET is not supplied:
 286          initial_address = &a[init];
 287       if OFFSET is supplied:
 288          initial_address = &a[init + OFFSET];
 289
 290       Return the initial_address in INITIAL_ADDRESS.
 291
 292    2. Create a data-reference in the loop based on the new vector pointer vp,
 293       and using a new index variable 'idx' as follows:
 294
 295       vp' = vp + update
 296
 297       where if ONLY_INIT is true:
 298          update = zero
 299       and otherwise
 300          update = idx + vector_type_size
 301
 302       Return the pointer vp'.
 303
 304
 305    FORNOW: handle only aligned and consecutive accesses.  */
 306
 307 static tree
 308 vect_create_data_ref_ptr (tree stmt, block_stmt_iterator *bsi, tree offset,
 309                           tree *initial_address, bool only_init)
 310 {
 311   tree base_name;
 312   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
 313   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
 314   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
 315   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
 316   tree vect_ptr_type;
 317   tree vect_ptr;
 318   tree tag;
 319   tree new_temp;
 320   tree vec_stmt;
 321   tree new_stmt_list = NULL_TREE;
 322   tree idx;
 323   edge pe = loop_preheader_edge (loop);
 324   basic_block new_bb;
 325   tree vect_ptr_init;
 326   tree vectype_size;
 327   tree ptr_update;
 328   tree data_ref_ptr;
 329   tree type, tmp, size;
 330
 331   base_name =  build_fold_indirect_ref (unshare_expr (
 332                       STMT_VINFO_VECT_DR_BASE_ADDRESS (stmt_info)));
 333
 334   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 335     {
 336       tree data_ref_base = base_name;
 337       fprintf (vect_dump, "create array_ref of type: ");
 338       print_generic_expr (vect_dump, vectype, TDF_SLIM);
 339       if (TREE_CODE (data_ref_base) == VAR_DECL)
 340         fprintf (vect_dump, "  vectorizing a one dimensional array ref: ");
 341       else if (TREE_CODE (data_ref_base) == ARRAY_REF)
 342         fprintf (vect_dump, "  vectorizing a multidimensional array ref: ");
 343       else if (TREE_CODE (data_ref_base) == COMPONENT_REF)
 344         fprintf (vect_dump, "  vectorizing a record based array ref: ");
 345       else if (TREE_CODE (data_ref_base) == SSA_NAME)
 346         fprintf (vect_dump, "  vectorizing a pointer ref: ");
 347       print_generic_expr (vect_dump, base_name, TDF_SLIM);
 348     }
 349
 350   /** (1) Create the new vector-pointer variable:  **/
 351
 352   vect_ptr_type = build_pointer_type (vectype);
 353   vect_ptr = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var,
 354                                     get_name (base_name));
 355   add_referenced_tmp_var (vect_ptr);
 356
 357
 358   /** (2) Add aliasing information to the new vector-pointer:
 359           (The points-to info (SSA_NAME_PTR_INFO) may be defined later.)  **/
 360
 361   tag = STMT_VINFO_MEMTAG (stmt_info);
 362   gcc_assert (tag);
 363
 364   /* If tag is a variable (and NOT_A_TAG) than a new type alias
 365      tag must be created with tag added to its may alias list.  */
 366   if (var_ann (tag)->mem_tag_kind == NOT_A_TAG)
 367     new_type_alias (vect_ptr, tag);
 368   else
 369     var_ann (vect_ptr)->type_mem_tag = tag;
 370
 371   var_ann (vect_ptr)->subvars = STMT_VINFO_SUBVARS (stmt_info);
 372
 373   /** (3) Calculate the initial address the vector-pointer, and set
 374           the vector-pointer to point to it before the loop:  **/
 375
 376   /* Create: (&(base[init_val+offset]) in the loop preheader.  */
 377   new_temp = vect_create_addr_base_for_vector_ref (stmt, &new_stmt_list,
 378                                                    offset);
 379   pe = loop_preheader_edge (loop);
 380   new_bb = bsi_insert_on_edge_immediate (pe, new_stmt_list);
 381   gcc_assert (!new_bb);
 382   *initial_address = new_temp;
 383
 384   /* Create: p = (vectype *) initial_base  */
 385   vec_stmt = fold_convert (vect_ptr_type, new_temp);
 386   vec_stmt = build2 (MODIFY_EXPR, void_type_node, vect_ptr, vec_stmt);
 387   new_temp = make_ssa_name (vect_ptr, vec_stmt);
 388   TREE_OPERAND (vec_stmt, 0) = new_temp;
 389   new_bb = bsi_insert_on_edge_immediate (pe, vec_stmt);
 390   gcc_assert (!new_bb);
 391   vect_ptr_init = TREE_OPERAND (vec_stmt, 0);
 392
 393
 394   /** (4) Handle the updating of the vector-pointer inside the loop: **/
 395
 396   if (only_init) /* No update in loop is required.  */
 397     {
 398       /* Copy the points-to information if it exists. */
 399       if (STMT_VINFO_PTR_INFO (stmt_info))
 400         duplicate_ssa_name_ptr_info (vect_ptr_init,
 401                                      STMT_VINFO_PTR_INFO (stmt_info));
 402       return vect_ptr_init;
 403     }
 404
 405   idx = vect_create_index_for_vector_ref (loop_vinfo);
 406
 407   /* Create: update = idx * vectype_size  */
 408   tmp = create_tmp_var (integer_type_node, "update");
 409   add_referenced_tmp_var (tmp);
 410   size = TYPE_SIZE (vect_ptr_type);
 411   type = lang_hooks.types.type_for_size (tree_low_cst (size, 1), 1);
 412   ptr_update = create_tmp_var (type, "update");
 413   add_referenced_tmp_var (ptr_update);
 414   vectype_size = TYPE_SIZE_UNIT (vectype);
 415   vec_stmt = build2 (MULT_EXPR, integer_type_node, idx, vectype_size);
 416   vec_stmt = build2 (MODIFY_EXPR, void_type_node, tmp, vec_stmt);
 417   new_temp = make_ssa_name (tmp, vec_stmt);
 418   TREE_OPERAND (vec_stmt, 0) = new_temp;
 419   bsi_insert_before (bsi, vec_stmt, BSI_SAME_STMT);
 420   vec_stmt = fold_convert (type, new_temp);
 421   vec_stmt = build2 (MODIFY_EXPR, void_type_node, ptr_update, vec_stmt);
 422   new_temp = make_ssa_name (ptr_update, vec_stmt);
 423   TREE_OPERAND (vec_stmt, 0) = new_temp;
 424   bsi_insert_before (bsi, vec_stmt, BSI_SAME_STMT);
 425
 426   /* Create: data_ref_ptr = vect_ptr_init + update  */
 427   vec_stmt = build2 (PLUS_EXPR, vect_ptr_type, vect_ptr_init, new_temp);
 428   vec_stmt = build2 (MODIFY_EXPR, void_type_node, vect_ptr, vec_stmt);
 429   new_temp = make_ssa_name (vect_ptr, vec_stmt);
 430   TREE_OPERAND (vec_stmt, 0) = new_temp;
 431   bsi_insert_before (bsi, vec_stmt, BSI_SAME_STMT);
 432   data_ref_ptr = TREE_OPERAND (vec_stmt, 0);
 433
 434   /* Copy the points-to information if it exists. */
 435   if (STMT_VINFO_PTR_INFO (stmt_info))
 436     duplicate_ssa_name_ptr_info (data_ref_ptr, STMT_VINFO_PTR_INFO (stmt_info));
 437   return data_ref_ptr;
 438 }
 439
 440
 441 /* Function vect_create_destination_var.
 442
 443    Create a new temporary of type VECTYPE.  */
 444
 445 static tree
 446 vect_create_destination_var (tree scalar_dest, tree vectype)
 447 {
 448   tree vec_dest;
 449   const char *new_name;
 450   tree type;
 451   enum vect_var_kind kind;
 452
 453   kind = vectype ? vect_simple_var : vect_scalar_var;
 454   type = vectype ? vectype : TREE_TYPE (scalar_dest);
 455
 456   gcc_assert (TREE_CODE (scalar_dest) == SSA_NAME);
 457
 458   new_name = get_name (scalar_dest);
 459   if (!new_name)
 460     new_name = "var_";
 461   vec_dest = vect_get_new_vect_var (type, vect_simple_var, new_name);
 462   add_referenced_tmp_var (vec_dest);
 463
 464   return vec_dest;
 465 }
 466
 467
 468 /* Function vect_init_vector.
 469
 470    Insert a new stmt (INIT_STMT) that initializes a new vector variable with
 471    the vector elements of VECTOR_VAR. Return the DEF of INIT_STMT. It will be
 472    used in the vectorization of STMT.  */
 473
 474 static tree
 475 vect_init_vector (tree stmt, tree vector_var)
 476 {
 477   stmt_vec_info stmt_vinfo = vinfo_for_stmt (stmt);
 478   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_vinfo);
 479   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
 480   tree new_var;
 481   tree init_stmt;
 482   tree vectype = STMT_VINFO_VECTYPE (stmt_vinfo);
 483   tree vec_oprnd;
 484   edge pe;
 485   tree new_temp;
 486   basic_block new_bb;
 487
 488   new_var = vect_get_new_vect_var (vectype, vect_simple_var, "cst_");
 489   add_referenced_tmp_var (new_var);
 490
 491   init_stmt = build2 (MODIFY_EXPR, vectype, new_var, vector_var);
 492   new_temp = make_ssa_name (new_var, init_stmt);
 493   TREE_OPERAND (init_stmt, 0) = new_temp;
 494
 495   pe = loop_preheader_edge (loop);
 496   new_bb = bsi_insert_on_edge_immediate (pe, init_stmt);
 497   gcc_assert (!new_bb);
 498
 499   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 500     {
 501       fprintf (vect_dump, "created new init_stmt: ");
 502       print_generic_expr (vect_dump, init_stmt, TDF_SLIM);
 503     }
 504
 505   vec_oprnd = TREE_OPERAND (init_stmt, 0);
 506   return vec_oprnd;
 507 }
 508
 509
 510 /* Function vect_get_vec_def_for_operand.
 511
 512    OP is an operand in STMT. This function returns a (vector) def that will be
 513    used in the vectorized stmt for STMT.
 514
 515    In the case that OP is an SSA_NAME which is defined in the loop, then
 516    STMT_VINFO_VEC_STMT of the defining stmt holds the relevant def.
 517
 518    In case OP is an invariant or constant, a new stmt that creates a vector def
 519    needs to be introduced.  */
 520
 521 static tree
 522 vect_get_vec_def_for_operand (tree op, tree stmt, tree *scalar_def)
 523 {
 524   tree vec_oprnd;
 525   tree vec_stmt;
 526   tree def_stmt;
 527   stmt_vec_info def_stmt_info = NULL;
 528   stmt_vec_info stmt_vinfo = vinfo_for_stmt (stmt);
 529   tree vectype = STMT_VINFO_VECTYPE (stmt_vinfo);
 530   int nunits = TYPE_VECTOR_SUBPARTS (vectype);
 531   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_vinfo);
 532   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
 533   tree vec_inv;
 534   tree vec_cst;
 535   tree t = NULL_TREE;
 536   tree def;
 537   int i;
 538   enum vect_def_type dt;
 539   bool is_simple_use;
 540
 541   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 542     {
 543       fprintf (vect_dump, "vect_get_vec_def_for_operand: ");
 544       print_generic_expr (vect_dump, op, TDF_SLIM);
 545     }
 546
 547   is_simple_use = vect_is_simple_use (op, loop_vinfo, &def_stmt, &def, &dt);
 548   gcc_assert (is_simple_use);
 549   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 550     {
 551       if (def)
 552         {
 553           fprintf (vect_dump, "def =  ");
 554           print_generic_expr (vect_dump, def, TDF_SLIM);
 555         }
 556       if (def_stmt)
 557         {
 558           fprintf (vect_dump, "  def_stmt =  ");
 559           print_generic_expr (vect_dump, def_stmt, TDF_SLIM);
 560         }
 561     }
 562
 563   switch (dt)
 564     {
 565     /* Case 1: operand is a constant.  */
 566     case vect_constant_def:
 567       {
 568         if (scalar_def)
 569           *scalar_def = op;
 570
 571         /* Create 'vect_cst_ = {cst,cst,...,cst}'  */
 572         if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 573           fprintf (vect_dump, "Create vector_cst. nunits = %d", nunits);
 574
 575         for (i = nunits - 1; i >= 0; --i)
 576           {
 577             t = tree_cons (NULL_TREE, op, t);
 578           }
 579         vec_cst = build_vector (vectype, t);
 580         return vect_init_vector (stmt, vec_cst);
 581       }
 582
 583     /* Case 2: operand is defined outside the loop - loop invariant.  */
 584     case vect_invariant_def:
 585       {
 586         if (scalar_def)
 587           *scalar_def = def;
 588
 589         /* Create 'vec_inv = {inv,inv,..,inv}'  */
 590         if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 591           fprintf (vect_dump, "Create vector_inv.");
 592
 593         for (i = nunits - 1; i >= 0; --i)
 594           {
 595             t = tree_cons (NULL_TREE, def, t);
 596           }
 597
 598         vec_inv = build_constructor (vectype, t);
 599         return vect_init_vector (stmt, vec_inv);
 600       }
 601
 602     /* Case 3: operand is defined inside the loop.  */
 603     case vect_loop_def:
 604       {
 605         if (scalar_def)
 606           *scalar_def = def_stmt;
 607
 608         /* Get the def from the vectorized stmt.  */
 609         def_stmt_info = vinfo_for_stmt (def_stmt);
 610         vec_stmt = STMT_VINFO_VEC_STMT (def_stmt_info);
 611         gcc_assert (vec_stmt);
 612         vec_oprnd = TREE_OPERAND (vec_stmt, 0);
 613         return vec_oprnd;
 614       }
 615
 616     /* Case 4: operand is defined by a loop header phi - reduction  */
 617     case vect_reduction_def:
 618       {
 619         gcc_assert (TREE_CODE (def_stmt) == PHI_NODE);
 620
 621         /* Get the def before the loop  */
 622         op = PHI_ARG_DEF_FROM_EDGE (def_stmt, loop_preheader_edge (loop));
 623         return get_initial_def_for_reduction (stmt, op, scalar_def);
 624      }
 625
 626     /* Case 5: operand is defined by loop-header phi - induction.  */
 627     case vect_induction_def:
 628       {
 629         if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 630           fprintf (vect_dump, "induction - unsupported.");
 631         internal_error ("no support for induction"); /* FORNOW */
 632       }
 633
 634     default:
 635       gcc_unreachable ();
 636     }
 637 }
 638
 639
 640 /* Function vect_finish_stmt_generation.
 641
 642    Insert a new stmt.  */
 643
 644 static void
 645 vect_finish_stmt_generation (tree stmt, tree vec_stmt, block_stmt_iterator *bsi)
 646 {
 647   bsi_insert_before (bsi, vec_stmt, BSI_SAME_STMT);
 648
 649   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 650     {
 651       fprintf (vect_dump, "add new stmt: ");
 652       print_generic_expr (vect_dump, vec_stmt, TDF_SLIM);
 653     }
 654
 655   /* Make sure bsi points to the stmt that is being vectorized.  */
 656   gcc_assert (stmt == bsi_stmt (*bsi));
 657
 658 #ifdef USE_MAPPED_LOCATION
 659   SET_EXPR_LOCATION (vec_stmt, EXPR_LOCATION (stmt));
 660 #else
 661   SET_EXPR_LOCUS (vec_stmt, EXPR_LOCUS (stmt));
 662 #endif
 663 }
 664
 665
 666 #define ADJUST_IN_EPILOG 1
 667
 668 /* Function get_initial_def_for_reduction
 669
 670    Input:
 671    STMT - a stmt that performs a reduction operation in the loop.
 672    INIT_VAL - the initial value of the reduction variable
 673
 674    Output:
 675    SCALAR_DEF - a tree that holds a value to be added to the final result
 676         of the reduction (used for "ADJUST_IN_EPILOG" - see below).
 677    Return a vector variable, initialized according to the operation that STMT
 678         performs. This vector will be used as the initial value of the
 679         vector of partial results.
 680
 681    Option1 ("ADJUST_IN_EPILOG"): Initialize the vector as follows:
 682      add:         [0,0,...,0,0]
 683      mult:        [1,1,...,1,1]
 684      min/max:     [init_val,init_val,..,init_val,init_val]
 685      bit and/or:  [init_val,init_val,..,init_val,init_val]
 686    and when necessary (e.g. add/mult case) let the caller know
 687    that it needs to adjust the result by init_val.
 688
 689    Option2: Initialize the vector as follows:
 690      add:         [0,0,...,0,init_val]
 691      mult:        [1,1,...,1,init_val]
 692      min/max:     [init_val,init_val,...,init_val]
 693      bit and/or:  [init_val,init_val,...,init_val]
 694    and no adjustments are needed.
 695
 696    For example, for the following code:
 697
 698    s = init_val;
 699    for (i=0;i<n;i++)
 700      s = s + a[i];
 701
 702    STMT is 's = s + a[i]', and the reduction variable is 's'.
 703    For a vector of 4 units, we want to return either [0,0,0,init_val],
 704    or [0,0,0,0] and let the caller know that it needs to adjust
 705    the result at the end by 'init_val'.
 706
 707    FORNOW: We use the "ADJUST_IN_EPILOG" scheme.
 708    TODO: Use some cost-model to estimate which scheme is more profitable.
 709 */
 710
 711 static tree
 712 get_initial_def_for_reduction (tree stmt, tree init_val, tree *scalar_def)
 713 {
 714   stmt_vec_info stmt_vinfo = vinfo_for_stmt (stmt);
 715   tree vectype = STMT_VINFO_VECTYPE (stmt_vinfo);
 716   int nunits = GET_MODE_NUNITS (TYPE_MODE (vectype));
 717   int nelements;
 718   enum tree_code code = TREE_CODE (TREE_OPERAND (stmt, 1));
 719   tree type = TREE_TYPE (init_val);
 720   tree def;
 721   tree vec, t = NULL_TREE;
 722   bool need_epilog_adjust;
 723   int i;
 724
 725   gcc_assert (INTEGRAL_TYPE_P (type) || SCALAR_FLOAT_TYPE_P (type));
 726
 727   switch (code)
 728   {
 729   case PLUS_EXPR:
 730     def = INTEGRAL_TYPE_P (type) ? integer_zero_node :
 731                                    build_real (type, dconst0);
 732 #ifdef ADJUST_IN_EPILOG
 733     /* All the 'nunits' elements are set to 0. The final result will be
 734        adjusted by 'init_val' at the loop epilog.  */
 735     nelements = nunits;
 736     need_epilog_adjust = true;
 737 #else
 738     /* 'nunits - 1' elements are set to 0; The last element is set to
 739         'init_val'.  No further adjustments at the epilog are needed.  */
 740     nelements = nunits - 1;
 741     need_epilog_adjust = false;
 742 #endif
 743     break;
 744
 745   case MIN_EXPR:
 746   case MAX_EXPR:
 747     def = init_val;
 748     nelements = nunits;
 749     need_epilog_adjust = false;
 750     break;
 751
 752   default:
 753     gcc_unreachable ();
 754   }
 755
 756   for (i = nelements - 1; i >= 0; --i)
 757     {
 758       t = tree_cons (NULL_TREE, def, t);
 759     }
 760
 761   if (nelements == nunits - 1)
 762     {
 763       /* Set the last element of the vector.  */
 764       t = tree_cons (NULL_TREE, init_val, t);
 765       nelements += 1;
 766     }
 767   gcc_assert (nelements == nunits);
 768
 769   if (TREE_CODE (init_val) == INTEGER_CST || TREE_CODE (init_val) == REAL_CST)
 770     vec = build_vector (vectype, t);
 771   else
 772     vec = build_constructor (vectype, t);
 773
 774   if (need_epilog_adjust)
 775     *scalar_def = init_val;
 776   else
 777     *scalar_def = INTEGRAL_TYPE_P (type) ? integer_zero_node
 778                                            : build_real (type, dconst0);
 779   return vect_init_vector (stmt, vec);
 780 }
 781
 782
 783 /* Function vect_create_epilog_for_reduction:
 784
 785    Create code at the loop-epilog to finalize the result of a reduction
 786    computation.
 787
 788    LOOP_EXIT_VECT_DEF is a vector of partial results. We need to "reduce" it
 789    into a single result, by applying the operation REDUC_CODE on the
 790    partial-results-vector. For this, we need to create a new phi node at the
 791    loop exit to preserve loop-closed form, as illustrated below.
 792
 793    STMT is the original scalar reduction stmt that is being vectorized.
 794    REDUCTION_OP is the scalar reduction-variable.
 795    REDUCTION_PHI is the phi-node that carries the reduction computation.
 796    This function also sets the arguments for the REDUCTION_PHI:
 797    The loop-entry argument is the (vectorized) initial-value of REDUCTION_OP.
 798    The loop-latch argument is VECT_DEF - the vector of partial sums.
 799
 800      This function transforms this:
 801
 802         loop:
 803           vec_def = phi <null, null>    # REDUCTION_PHI
 804           ....
 805           VECT_DEF = ...
 806
 807         loop_exit:
 808           s_out0 = phi <s_loop>         # EXIT_PHI
 809
 810           use <s_out0>
 811           use <s_out0>
 812
 813      Into:
 814
 815         loop:
 816           vec_def = phi <vec_init, VECT_DEF> # REDUCTION_PHI
 817           ....
 818           VECT_DEF = ...
 819
 820         loop_exit:
 821           s_out0 = phi <s_loop>         # EXIT_PHI
 822           v_out1 = phi <VECT_DEF>       # NEW_EXIT_PHI
 823
 824           v_out2 = reduc_expr <v_out1>
 825           s_out3 = extract_field <v_out2, 0>
 826
 827           use <s_out3>
 828           use <s_out3>
 829 */
 830
 831 static void
 832 vect_create_epilog_for_reduction (tree vect_def, tree stmt, tree reduction_op,
 833                                   enum tree_code reduc_code, tree reduction_phi)
 834 {
 835   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
 836   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
 837   enum machine_mode mode = TYPE_MODE (vectype);
 838   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
 839   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
 840   basic_block exit_bb;
 841   tree scalar_dest = TREE_OPERAND (stmt, 0);
 842   tree scalar_type = TREE_TYPE (scalar_dest);
 843   tree new_phi;
 844   block_stmt_iterator exit_bsi;
 845   tree vec_dest;
 846   tree new_temp;
 847   tree new_name;
 848   tree epilog_stmt;
 849   tree new_scalar_dest, exit_phi;
 850   tree bitsize, bitpos, bytesize;
 851   enum tree_code code = TREE_CODE (TREE_OPERAND (stmt, 1));
 852   tree scalar_initial_def;
 853   tree vec_initial_def;
 854   tree orig_name;
 855   imm_use_iterator imm_iter;
 856   use_operand_p use_p;
 857   bool extract_scalar_result;
 858   bool adjust_in_epilog;
 859
 860   /*** 1. Create the reduction def-use cycle  ***/
 861
 862   /* 1.1 set the loop-entry arg of the reduction-phi:  */
 863   /* For the case of reduction, vect_get_vec_def_for_operand returns
 864      the scalar def before the loop, that defines the initial value
 865      of the reduction variable.  */
 866   vec_initial_def = vect_get_vec_def_for_operand (reduction_op, stmt,
 867                                                   &scalar_initial_def);
 868   add_phi_arg (reduction_phi, vec_initial_def, loop_preheader_edge (loop));
 869
 870
 871   /* 1.2 set the loop-latch arg for the reduction-phi:  */
 872   add_phi_arg (reduction_phi, vect_def, loop_latch_edge (loop));
 873
 874   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 875     {
 876       fprintf (vect_dump, "transform reduction: created def-use cycle:");
 877       print_generic_expr (vect_dump, reduction_phi, TDF_SLIM);
 878       fprintf (vect_dump, "\n");
 879       print_generic_expr (vect_dump, SSA_NAME_DEF_STMT (vect_def), TDF_SLIM);
 880     }
 881
 882
 883   /*** 2. Create epilog code ***/
 884
 885   /* 2.1 Create new loop-exit-phi to preserve loop-closed form:
 886         v_out1 = phi <v_loop>  */
 887
 888   exit_bb = loop->single_exit->dest;
 889   new_phi = create_phi_node (SSA_NAME_VAR (vect_def), exit_bb);
 890   SET_PHI_ARG_DEF (new_phi, loop->single_exit->dest_idx, vect_def);
 891
 892   exit_bsi = bsi_start (exit_bb);
 893
 894
 895   new_scalar_dest = vect_create_destination_var (scalar_dest, NULL);
 896   bitsize = TYPE_SIZE (scalar_type);
 897   bytesize = TYPE_SIZE_UNIT (scalar_type);
 898
 899   /* 2.2 Create the reduction code.  */
 900
 901   if (reduc_code < NUM_TREE_CODES)
 902     {
 903       /*** Case 1:  Create:
 904            v_out2 = reduc_expr <v_out1>  */
 905
 906       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 907         fprintf (vect_dump, "Reduce using direct vector reduction.");
 908
 909       vec_dest = vect_create_destination_var (scalar_dest, vectype);
 910       epilog_stmt = build2 (MODIFY_EXPR, vectype, vec_dest,
 911                         build1 (reduc_code, vectype,  PHI_RESULT (new_phi)));
 912       new_temp = make_ssa_name (vec_dest, epilog_stmt);
 913       TREE_OPERAND (epilog_stmt, 0) = new_temp;
 914       bsi_insert_after (&exit_bsi, epilog_stmt, BSI_NEW_STMT);
 915
 916       extract_scalar_result = true;
 917       adjust_in_epilog = true;
 918     }
 919   else
 920     {
 921       enum tree_code shift_code;
 922       bool have_whole_vector_shift = true;
 923       enum tree_code code = TREE_CODE (TREE_OPERAND (stmt, 1)); /* CHECKME */
 924       int bit_offset;
 925       int element_bitsize = tree_low_cst (bitsize, 1);
 926       int vec_size_in_bits = tree_low_cst (TYPE_SIZE (vectype), 1);
 927       tree vec_temp;
 928
 929       /* The result of the reduction is expected to be at the LSB bits
 930          of the vector. For big-endian targets this means at the right
 931          end of the vector. For little-edian targets this means at the
 932          left end of the vector.  */
 933
 934       if (BITS_BIG_ENDIAN
 935           && vec_shr_optab->handlers[mode].insn_code != CODE_FOR_nothing)
 936         shift_code = VEC_RSHIFT_EXPR;
 937       else if (!BITS_BIG_ENDIAN
 938                && vec_shl_optab->handlers[mode].insn_code != CODE_FOR_nothing)
 939         shift_code = VEC_LSHIFT_EXPR;
 940       else
 941         have_whole_vector_shift = false;
 942
 943       if (have_whole_vector_shift)
 944         {
 945           /*** Case 2:
 946              for (offset = VS/2; offset >= element_size; offset/=2)
 947                 {
 948                   Create:  va' = vec_shift <va, offset>
 949                   Create:  va = vop <va, va'>
 950                 }  */
 951
 952           if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 953             fprintf (vect_dump, "Reduce using vector shifts");
 954
 955           vec_dest = vect_create_destination_var (scalar_dest, vectype);
 956           new_temp = PHI_RESULT (new_phi);
 957
 958           for (bit_offset = vec_size_in_bits/2;
 959                bit_offset >= element_bitsize;
 960                bit_offset /= 2)
 961             {
 962               tree bitpos = size_int (bit_offset);
 963
 964               epilog_stmt = build2 (MODIFY_EXPR, vectype, vec_dest,
 965               build2 (shift_code, vectype, new_temp, bitpos));
 966               new_name = make_ssa_name (vec_dest, epilog_stmt);
 967               TREE_OPERAND (epilog_stmt, 0) = new_name;
 968               bsi_insert_after (&exit_bsi, epilog_stmt, BSI_NEW_STMT);
 969               if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 970                 print_generic_expr (vect_dump, epilog_stmt, TDF_SLIM);
 971
 972
 973               epilog_stmt = build2 (MODIFY_EXPR, vectype, vec_dest,
 974               build2 (code, vectype, new_name, new_temp));
 975               new_temp = make_ssa_name (vec_dest, epilog_stmt);
 976               TREE_OPERAND (epilog_stmt, 0) = new_temp;
 977               bsi_insert_after (&exit_bsi, epilog_stmt, BSI_NEW_STMT);
 978               if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 979                 print_generic_expr (vect_dump, epilog_stmt, TDF_SLIM);
 980             }
 981
 982           extract_scalar_result = true;
 983           adjust_in_epilog = true;
 984         }
 985       else
 986         {
 987           /*** Case 3:
 988              Create:  s = init;
 989              for (offset=0; offset<vector_size; offset+=element_size;)
 990                {
 991                  Create:  s' = extract_field <v_out2, offset>
 992                  Create:  s = op <s, s'>
 993                }  */
 994
 995           if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
 996             fprintf (vect_dump, "Reduce using scalar code. ");
 997
 998           vec_temp = PHI_RESULT (new_phi);
 999           vec_size_in_bits = tree_low_cst (TYPE_SIZE (vectype), 1);
1000
1001           /* first iteration is peeled out when possible to minimize
1002              the number of operations we generate:  */
1003           if (code == PLUS_EXPR
1004              && (integer_zerop (scalar_initial_def)
1005                  || real_zerop (scalar_initial_def)))
1006             {
1007               epilog_stmt = build2 (MODIFY_EXPR, scalar_type, new_scalar_dest,
1008                                 build3 (BIT_FIELD_REF, scalar_type,
1009                                         vec_temp, bitsize, bitsize_zero_node));
1010               new_temp = make_ssa_name (new_scalar_dest, epilog_stmt);
1011               TREE_OPERAND (epilog_stmt, 0) = new_temp;
1012               bsi_insert_after (&exit_bsi, epilog_stmt, BSI_NEW_STMT);
1013               if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1014                 print_generic_expr (vect_dump, epilog_stmt, TDF_SLIM);
1015
1016               bit_offset = element_bitsize;
1017             }
1018           else
1019             {
1020               new_temp = scalar_initial_def;
1021               bit_offset = 0;
1022             }
1023
1024           for (;
1025                bit_offset < vec_size_in_bits;
1026                bit_offset += element_bitsize)
1027             {
1028               tree bitpos = bitsize_int (bit_offset);
1029
1030               epilog_stmt = build2 (MODIFY_EXPR, scalar_type, new_scalar_dest,
1031                                 build3 (BIT_FIELD_REF, scalar_type,
1032                                         vec_temp, bitsize, bitpos));
1033               new_name = make_ssa_name (new_scalar_dest, epilog_stmt);
1034               TREE_OPERAND (epilog_stmt, 0) = new_name;
1035               bsi_insert_after (&exit_bsi, epilog_stmt, BSI_NEW_STMT);
1036               if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1037                 print_generic_expr (vect_dump, epilog_stmt, TDF_SLIM);
1038
1039
1040               epilog_stmt = build2 (MODIFY_EXPR, scalar_type, new_scalar_dest,
1041                                 build2 (code, scalar_type, new_name, new_temp));
1042               new_temp = make_ssa_name (new_scalar_dest, epilog_stmt);
1043               TREE_OPERAND (epilog_stmt, 0) = new_temp;
1044               bsi_insert_after (&exit_bsi, epilog_stmt, BSI_NEW_STMT);
1045               if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1046                 print_generic_expr (vect_dump, epilog_stmt, TDF_SLIM);
1047             }
1048
1049           extract_scalar_result = false;
1050           adjust_in_epilog = false;
1051         }
1052     }
1053
1054
1055   /* 2.3  Extract the final scalar result.  Create:
1056          s_out3 = extract_field <v_out2, bitpos>  */
1057
1058   if (extract_scalar_result)
1059     {
1060       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1061         fprintf (vect_dump, "extract scalar result");
1062
1063       /* The result is in the low order bits.  */
1064       if (BITS_BIG_ENDIAN)
1065         bitpos = size_binop (MULT_EXPR,
1066                        bitsize_int (TYPE_VECTOR_SUBPARTS (vectype) - 1),
1067                        TYPE_SIZE (scalar_type));
1068       else
1069         bitpos = bitsize_zero_node;
1070
1071       epilog_stmt = build2 (MODIFY_EXPR, scalar_type, new_scalar_dest,
1072                      build3 (BIT_FIELD_REF, scalar_type,
1073                              new_temp, bitsize, bitpos));
1074       new_temp = make_ssa_name (new_scalar_dest, epilog_stmt);
1075       TREE_OPERAND (epilog_stmt, 0) = new_temp;
1076       bsi_insert_after (&exit_bsi, epilog_stmt, BSI_NEW_STMT);
1077       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1078         print_generic_expr (vect_dump, epilog_stmt, TDF_SLIM);
1079     }
1080
1081
1082   /* 2.4 Adjust the final result by the initial value of the reduction
1083          variable. (when such adjustment is not needed, then
1084          'scalar_initial_def' is zero).
1085
1086          Create:
1087          s_out = scalar_expr <s_out, scalar_initial_def>  */
1088
1089   if (adjust_in_epilog)
1090     {
1091       epilog_stmt = build2 (MODIFY_EXPR, scalar_type, new_scalar_dest,
1092                       build2 (code, scalar_type, new_temp, scalar_initial_def));
1093       new_temp = make_ssa_name (new_scalar_dest, epilog_stmt);
1094       TREE_OPERAND (epilog_stmt, 0) = new_temp;
1095       bsi_insert_after (&exit_bsi, epilog_stmt, BSI_NEW_STMT);
1096
1097       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1098         print_generic_expr (vect_dump, epilog_stmt, TDF_SLIM);
1099     }
1100
1101
1102   /* 2.5 Replace uses of s_out0 with uses of s_out3  */
1103
1104   /* Find the loop-closed-use at the loop exit of the original
1105      scalar result.  (The reduction result is expected to have
1106      two immediate uses - one at the latch block, and one at the
1107      loop exit).  */
1108   exit_phi = NULL;
1109   FOR_EACH_IMM_USE_FAST (use_p, imm_iter, scalar_dest)
1110     {
1111       if (!flow_bb_inside_loop_p (loop, bb_for_stmt (USE_STMT (use_p))))
1112         {
1113           exit_phi = USE_STMT (use_p);
1114           break;
1115         }
1116     }
1117
1118   orig_name = PHI_RESULT (exit_phi);
1119
1120   FOR_EACH_IMM_USE_SAFE (use_p, imm_iter, orig_name)
1121     SET_USE (use_p, new_temp);
1122 }
1123
1124
1125 /* Function vectorizable_reduction.
1126
1127    Check if STMT performs a reduction operation that can be vectorized.
1128    If VEC_STMT is also passed, vectorize the STMT: create a vectorized
1129    stmt to replace it, put it in VEC_STMT, and insert it at BSI.
1130    Return FALSE if not a vectorizable STMT, TRUE otherwise.  */
1131
1132 bool
1133 vectorizable_reduction (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt)
1134 {
1135   tree vec_dest;
1136   tree scalar_dest;
1137   tree op0, op1;
1138   tree loop_vec_def;
1139   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1140   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
1141   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1142   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1143   tree operation;
1144   enum tree_code code, reduc_code = 0;
1145   enum machine_mode vec_mode;
1146   int op_type;
1147   optab optab, reduc_optab;
1148   tree new_temp;
1149   tree def0, def1, def_stmt0, def_stmt1;
1150   enum vect_def_type dt0, dt1;
1151   tree new_phi;
1152   tree scalar_type;
1153   bool is_simple_use0;
1154   bool is_simple_use1;
1155
1156   /* Is vectorizable reduction?  */
1157
1158   /* Not supportable if the reduction variable is used in the loop.  */
1159   if (STMT_VINFO_RELEVANT_P (stmt_info))
1160     return false;
1161
1162   if (!STMT_VINFO_LIVE_P (stmt_info))
1163     return false;
1164
1165   /* Make sure it was already recognized as a reduction pattern.  */
1166   if (STMT_VINFO_DEF_TYPE (stmt_info) != vect_reduction_def)
1167     return false;
1168
1169   gcc_assert (TREE_CODE (stmt) == MODIFY_EXPR);
1170
1171   operation = TREE_OPERAND (stmt, 1);
1172   code = TREE_CODE (operation);
1173   op_type = TREE_CODE_LENGTH (code);
1174
1175   if (op_type != binary_op)
1176     return false;
1177
1178   op0 = TREE_OPERAND (operation, 0);
1179   op1 = TREE_OPERAND (operation, 1);
1180   scalar_dest = TREE_OPERAND (stmt, 0);
1181   scalar_type = TREE_TYPE (scalar_dest);
1182
1183   /* Check the first operand. It is expected to be defined inside the loop.  */
1184   is_simple_use0 =
1185         vect_is_simple_use (op0, loop_vinfo, &def_stmt0, &def0, &dt0);
1186   is_simple_use1 =
1187         vect_is_simple_use (op1, loop_vinfo, &def_stmt1, &def1, &dt1);
1188
1189   gcc_assert (is_simple_use0);
1190   gcc_assert (is_simple_use1);
1191   gcc_assert (dt0 == vect_loop_def);
1192   gcc_assert (dt1 == vect_reduction_def);
1193   gcc_assert (TREE_CODE (def_stmt1) == PHI_NODE);
1194   gcc_assert (stmt == vect_is_simple_reduction (loop, def_stmt1));
1195
1196   if (STMT_VINFO_LIVE_P (vinfo_for_stmt (def_stmt1)))
1197    return false;
1198
1199   /* Supportable by target?  */
1200
1201   /* check support for the operation in the loop  */
1202   optab = optab_for_tree_code (code, vectype);
1203   if (!optab)
1204     {
1205       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1206         fprintf (vect_dump, "no optab.");
1207       return false;
1208     }
1209   vec_mode = TYPE_MODE (vectype);
1210   if (optab->handlers[(int) vec_mode].insn_code == CODE_FOR_nothing)
1211     {
1212       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1213         fprintf (vect_dump, "op not supported by target.");
1214       return false;
1215     }
1216
1217   /* check support for the epilog operation  */
1218   if (!reduction_code_for_scalar_code (code, &reduc_code))
1219     return false;
1220   reduc_optab = optab_for_tree_code (reduc_code, vectype);
1221   if (!reduc_optab)
1222     {
1223       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1224         fprintf (vect_dump, "no optab for reduction.");
1225       reduc_code = NUM_TREE_CODES;
1226     }
1227   if (reduc_optab->handlers[(int) vec_mode].insn_code == CODE_FOR_nothing)
1228     {
1229       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1230         fprintf (vect_dump, "reduc op not supported by target.");
1231       reduc_code = NUM_TREE_CODES;
1232     }
1233
1234   if (!vec_stmt) /* transformation not required.  */
1235     {
1236       STMT_VINFO_TYPE (stmt_info) = reduc_vec_info_type;
1237       return true;
1238     }
1239
1240   /** Transform.  **/
1241
1242   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1243     fprintf (vect_dump, "transform reduction.");
1244
1245   /* Create the destination vector  */
1246   vec_dest = vect_create_destination_var (scalar_dest, vectype);
1247
1248
1249   /* Create the reduction-phi that defines the reduction-operand.  */
1250   new_phi = create_phi_node (vec_dest, loop->header);
1251
1252
1253   /* Prepare the operand that is defined inside the loop body  */
1254   loop_vec_def = vect_get_vec_def_for_operand (op0, stmt, NULL);
1255   gcc_assert (VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (loop_vec_def))));
1256
1257
1258   /* Create the vectorized operation that computes the partial results  */
1259   *vec_stmt = build2 (MODIFY_EXPR, vectype, vec_dest,
1260                 build2 (code, vectype, loop_vec_def, PHI_RESULT (new_phi)));
1261   new_temp = make_ssa_name (vec_dest, *vec_stmt);
1262   TREE_OPERAND (*vec_stmt, 0) = new_temp;
1263   vect_finish_stmt_generation (stmt, *vec_stmt, bsi);
1264
1265
1266   /* Finalize the reduction-phi (set it's arguments) and create the
1267      epilog reduction code.  */
1268   vect_create_epilog_for_reduction (new_temp, stmt, op1, reduc_code, new_phi);
1269   return true;
1270 }
1271
1272
1273 /* Function vectorizable_assignment.
1274
1275    Check if STMT performs an assignment (copy) that can be vectorized.
1276    If VEC_STMT is also passed, vectorize the STMT: create a vectorized
1277    stmt to replace it, put it in VEC_STMT, and insert it at BSI.
1278    Return FALSE if not a vectorizable STMT, TRUE otherwise.  */
1279
1280 bool
1281 vectorizable_assignment (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt)
1282 {
1283   tree vec_dest;
1284   tree scalar_dest;
1285   tree op;
1286   tree vec_oprnd;
1287   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1288   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
1289   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1290   tree new_temp;
1291   tree def, def_stmt;
1292   enum vect_def_type dt;
1293
1294   /* Is vectorizable assignment?  */
1295   if (!STMT_VINFO_RELEVANT_P (stmt_info))
1296     return false;
1297
1298   gcc_assert (STMT_VINFO_DEF_TYPE (stmt_info) == vect_loop_def);
1299
1300   if (TREE_CODE (stmt) != MODIFY_EXPR)
1301     return false;
1302
1303   scalar_dest = TREE_OPERAND (stmt, 0);
1304   if (TREE_CODE (scalar_dest) != SSA_NAME)
1305     return false;
1306
1307   op = TREE_OPERAND (stmt, 1);
1308   if (!vect_is_simple_use (op, loop_vinfo, &def_stmt, &def, &dt))
1309     {
1310       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1311         fprintf (vect_dump, "use not simple.");
1312       return false;
1313     }
1314
1315   if (!vec_stmt) /* transformation not required.  */
1316     {
1317       STMT_VINFO_TYPE (stmt_info) = assignment_vec_info_type;
1318       return true;
1319     }
1320
1321   /** Transform.  **/
1322   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1323     fprintf (vect_dump, "transform assignment.");
1324
1325   /* Handle def.  */
1326   vec_dest = vect_create_destination_var (scalar_dest, vectype);
1327
1328   /* Handle use.  */
1329   op = TREE_OPERAND (stmt, 1);
1330   vec_oprnd = vect_get_vec_def_for_operand (op, stmt, NULL);
1331
1332   /* Arguments are ready. create the new vector stmt.  */
1333   *vec_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, vec_oprnd);
1334   new_temp = make_ssa_name (vec_dest, *vec_stmt);
1335   TREE_OPERAND (*vec_stmt, 0) = new_temp;
1336   vect_finish_stmt_generation (stmt, *vec_stmt, bsi);
1337
1338   return true;
1339 }
1340
1341
1342 /* Function vect_min_worthwhile_factor.
1343
1344    For a loop where we could vectorize the operation indicated by CODE,
1345    return the minimum vectorization factor that makes it worthwhile
1346    to use generic vectors.  */
1347 static int
1348 vect_min_worthwhile_factor (enum tree_code code)
1349 {
1350   switch (code)
1351     {
1352     case PLUS_EXPR:
1353     case MINUS_EXPR:
1354     case NEGATE_EXPR:
1355       return 4;
1356
1357     case BIT_AND_EXPR:
1358     case BIT_IOR_EXPR:
1359     case BIT_XOR_EXPR:
1360     case BIT_NOT_EXPR:
1361       return 2;
1362
1363     default:
1364       return INT_MAX;
1365     }
1366 }
1367
1368
1369 /* Function vectorizable_operation.
1370
1371    Check if STMT performs a binary or unary operation that can be vectorized.
1372    If VEC_STMT is also passed, vectorize the STMT: create a vectorized
1373    stmt to replace it, put it in VEC_STMT, and insert it at BSI.
1374    Return FALSE if not a vectorizable STMT, TRUE otherwise.  */
1375
1376 bool
1377 vectorizable_operation (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt)
1378 {
1379   tree vec_dest;
1380   tree scalar_dest;
1381   tree operation;
1382   tree op0, op1 = NULL;
1383   tree vec_oprnd0, vec_oprnd1=NULL;
1384   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1385   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
1386   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1387   int i;
1388   enum tree_code code;
1389   enum machine_mode vec_mode;
1390   tree new_temp;
1391   int op_type;
1392   tree op;
1393   optab optab;
1394   tree def, def_stmt;
1395   enum vect_def_type dt;
1396
1397   /* Is STMT a vectorizable binary/unary operation?   */
1398   if (!STMT_VINFO_RELEVANT_P (stmt_info))
1399     return false;
1400
1401   gcc_assert (STMT_VINFO_DEF_TYPE (stmt_info) == vect_loop_def);
1402
1403   if (STMT_VINFO_LIVE_P (stmt_info))
1404     {
1405       /* FORNOW: not yet supported.  */
1406       if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
1407         fprintf (vect_dump, "value used after loop.");
1408       return false;
1409     }
1410
1411   if (TREE_CODE (stmt) != MODIFY_EXPR)
1412     return false;
1413
1414   if (TREE_CODE (TREE_OPERAND (stmt, 0)) != SSA_NAME)
1415     return false;
1416
1417   operation = TREE_OPERAND (stmt, 1);
1418   code = TREE_CODE (operation);
1419   optab = optab_for_tree_code (code, vectype);
1420
1421   /* Support only unary or binary operations.  */
1422   op_type = TREE_CODE_LENGTH (code);
1423   if (op_type != unary_op && op_type != binary_op)
1424     {
1425       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1426         fprintf (vect_dump, "num. args = %d (not unary/binary op).", op_type);
1427       return false;
1428     }
1429
1430   for (i = 0; i < op_type; i++)
1431     {
1432       op = TREE_OPERAND (operation, i);
1433       if (!vect_is_simple_use (op, loop_vinfo, &def_stmt, &def, &dt))
1434         {
1435           if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1436             fprintf (vect_dump, "use not simple.");
1437           return false;
1438         }
1439     }
1440
1441   /* Supportable by target?  */
1442   if (!optab)
1443     {
1444       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1445         fprintf (vect_dump, "no optab.");
1446       return false;
1447     }
1448   vec_mode = TYPE_MODE (vectype);
1449   if (optab->handlers[(int) vec_mode].insn_code == CODE_FOR_nothing)
1450     {
1451       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1452         fprintf (vect_dump, "op not supported by target.");
1453       if (GET_MODE_SIZE (vec_mode) != UNITS_PER_WORD
1454           || LOOP_VINFO_VECT_FACTOR (loop_vinfo)
1455              < vect_min_worthwhile_factor (code))
1456         return false;
1457       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1458         fprintf (vect_dump, "proceeding using word mode.");
1459     }
1460
1461   /* Worthwhile without SIMD support?  */
1462   if (!VECTOR_MODE_P (TYPE_MODE (vectype))
1463       && LOOP_VINFO_VECT_FACTOR (loop_vinfo)
1464          < vect_min_worthwhile_factor (code))
1465     {
1466       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1467         fprintf (vect_dump, "not worthwhile without SIMD support.");
1468       return false;
1469     }
1470
1471   if (!vec_stmt) /* transformation not required.  */
1472     {
1473       STMT_VINFO_TYPE (stmt_info) = op_vec_info_type;
1474       return true;
1475     }
1476
1477   /** Transform.  **/
1478
1479   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1480     fprintf (vect_dump, "transform binary/unary operation.");
1481
1482   /* Handle def.  */
1483   scalar_dest = TREE_OPERAND (stmt, 0);
1484   vec_dest = vect_create_destination_var (scalar_dest, vectype);
1485
1486   /* Handle uses.  */
1487   op0 = TREE_OPERAND (operation, 0);
1488   vec_oprnd0 = vect_get_vec_def_for_operand (op0, stmt, NULL);
1489
1490   if (op_type == binary_op)
1491     {
1492       op1 = TREE_OPERAND (operation, 1);
1493       vec_oprnd1 = vect_get_vec_def_for_operand (op1, stmt, NULL);
1494     }
1495
1496   /* Arguments are ready. create the new vector stmt.  */
1497
1498   if (op_type == binary_op)
1499     *vec_stmt = build2 (MODIFY_EXPR, vectype, vec_dest,
1500                 build2 (code, vectype, vec_oprnd0, vec_oprnd1));
1501   else
1502     *vec_stmt = build2 (MODIFY_EXPR, vectype, vec_dest,
1503                 build1 (code, vectype, vec_oprnd0));
1504   new_temp = make_ssa_name (vec_dest, *vec_stmt);
1505   TREE_OPERAND (*vec_stmt, 0) = new_temp;
1506   vect_finish_stmt_generation (stmt, *vec_stmt, bsi);
1507
1508   return true;
1509 }
1510
1511
1512 /* Function vectorizable_store.
1513
1514    Check if STMT defines a non scalar data-ref (array/pointer/structure) that
1515    can be vectorized.
1516    If VEC_STMT is also passed, vectorize the STMT: create a vectorized
1517    stmt to replace it, put it in VEC_STMT, and insert it at BSI.
1518    Return FALSE if not a vectorizable STMT, TRUE otherwise.  */
1519
1520 bool
1521 vectorizable_store (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt)
1522 {
1523   tree scalar_dest;
1524   tree data_ref;
1525   tree op;
1526   tree vec_oprnd1;
1527   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1528   struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
1529   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
1530   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1531   enum machine_mode vec_mode;
1532   tree dummy;
1533   enum dr_alignment_support alignment_support_cheme;
1534   ssa_op_iter iter;
1535   tree def, def_stmt;
1536   enum vect_def_type dt;
1537
1538   /* Is vectorizable store? */
1539
1540   if (TREE_CODE (stmt) != MODIFY_EXPR)
1541     return false;
1542
1543   scalar_dest = TREE_OPERAND (stmt, 0);
1544   if (TREE_CODE (scalar_dest) != ARRAY_REF
1545       && TREE_CODE (scalar_dest) != INDIRECT_REF)
1546     return false;
1547
1548   op = TREE_OPERAND (stmt, 1);
1549   if (!vect_is_simple_use (op, loop_vinfo, &def_stmt, &def, &dt))
1550     {
1551       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1552         fprintf (vect_dump, "use not simple.");
1553       return false;
1554     }
1555
1556   vec_mode = TYPE_MODE (vectype);
1557   /* FORNOW. In some cases can vectorize even if data-type not supported
1558      (e.g. - array initialization with 0).  */
1559   if (mov_optab->handlers[(int)vec_mode].insn_code == CODE_FOR_nothing)
1560     return false;
1561
1562   if (!STMT_VINFO_DATA_REF (stmt_info))
1563     return false;
1564
1565
1566   if (!vec_stmt) /* transformation not required.  */
1567     {
1568       STMT_VINFO_TYPE (stmt_info) = store_vec_info_type;
1569       return true;
1570     }
1571
1572   /** Transform.  **/
1573
1574   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1575     fprintf (vect_dump, "transform store");
1576
1577   alignment_support_cheme = vect_supportable_dr_alignment (dr);
1578   gcc_assert (alignment_support_cheme);
1579   gcc_assert (alignment_support_cheme == dr_aligned);  /* FORNOW */
1580
1581   /* Handle use - get the vectorized def from the defining stmt.  */
1582   vec_oprnd1 = vect_get_vec_def_for_operand (op, stmt, NULL);
1583
1584   /* Handle def.  */
1585   /* FORNOW: make sure the data reference is aligned.  */
1586   vect_align_data_ref (stmt);
1587   data_ref = vect_create_data_ref_ptr (stmt, bsi, NULL_TREE, &dummy, false);
1588   data_ref = build_fold_indirect_ref (data_ref);
1589
1590   /* Arguments are ready. create the new vector stmt.  */
1591   *vec_stmt = build2 (MODIFY_EXPR, vectype, data_ref, vec_oprnd1);
1592   vect_finish_stmt_generation (stmt, *vec_stmt, bsi);
1593
1594   /* Copy the V_MAY_DEFS representing the aliasing of the original array
1595      element's definition to the vector's definition then update the
1596      defining statement.  The original is being deleted so the same
1597      SSA_NAMEs can be used.  */
1598   copy_virtual_operands (*vec_stmt, stmt);
1599
1600   FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_VMAYDEF)
1601     {
1602       SSA_NAME_DEF_STMT (def) = *vec_stmt;
1603
1604       /* If this virtual def has a use outside the loop and a loop peel is
1605          performed then the def may be renamed by the peel.  Mark it for
1606          renaming so the later use will also be renamed.  */
1607       mark_sym_for_renaming (SSA_NAME_VAR (def));
1608     }
1609
1610   return true;
1611 }
1612
1613
1614 /* vectorizable_load.
1615
1616    Check if STMT reads a non scalar data-ref (array/pointer/structure) that
1617    can be vectorized.
1618    If VEC_STMT is also passed, vectorize the STMT: create a vectorized
1619    stmt to replace it, put it in VEC_STMT, and insert it at BSI.
1620    Return FALSE if not a vectorizable STMT, TRUE otherwise.  */
1621
1622 bool
1623 vectorizable_load (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt)
1624 {
1625   tree scalar_dest;
1626   tree vec_dest = NULL;
1627   tree data_ref = NULL;
1628   tree op;
1629   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1630   struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
1631   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
1632   tree new_temp;
1633   int mode;
1634   tree init_addr;
1635   tree new_stmt;
1636   tree dummy;
1637   basic_block new_bb;
1638   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1639   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
1640   edge pe = loop_preheader_edge (loop);
1641   enum dr_alignment_support alignment_support_cheme;
1642
1643   /* Is vectorizable load? */
1644   if (!STMT_VINFO_RELEVANT_P (stmt_info))
1645     return false;
1646
1647   gcc_assert (STMT_VINFO_DEF_TYPE (stmt_info) == vect_loop_def);
1648
1649   if (STMT_VINFO_LIVE_P (stmt_info))
1650     {
1651       /* FORNOW: not yet supported.  */
1652       if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
1653         fprintf (vect_dump, "value used after loop.");
1654       return false;
1655     }
1656
1657   if (TREE_CODE (stmt) != MODIFY_EXPR)
1658     return false;
1659
1660   scalar_dest = TREE_OPERAND (stmt, 0);
1661   if (TREE_CODE (scalar_dest) != SSA_NAME)
1662     return false;
1663
1664   op = TREE_OPERAND (stmt, 1);
1665   if (TREE_CODE (op) != ARRAY_REF && TREE_CODE (op) != INDIRECT_REF)
1666     return false;
1667
1668   if (!STMT_VINFO_DATA_REF (stmt_info))
1669     return false;
1670
1671   mode = (int) TYPE_MODE (vectype);
1672
1673   /* FORNOW. In some cases can vectorize even if data-type not supported
1674     (e.g. - data copies).  */
1675   if (mov_optab->handlers[mode].insn_code == CODE_FOR_nothing)
1676     {
1677       if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
1678         fprintf (vect_dump, "Aligned load, but unsupported type.");
1679       return false;
1680     }
1681
1682   if (!vec_stmt) /* transformation not required.  */
1683     {
1684       STMT_VINFO_TYPE (stmt_info) = load_vec_info_type;
1685       return true;
1686     }
1687
1688   /** Transform.  **/
1689
1690   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1691     fprintf (vect_dump, "transform load.");
1692
1693   alignment_support_cheme = vect_supportable_dr_alignment (dr);
1694   gcc_assert (alignment_support_cheme);
1695
1696   if (alignment_support_cheme == dr_aligned
1697       || alignment_support_cheme == dr_unaligned_supported)
1698     {
1699       /* Create:
1700          p = initial_addr;
1701          indx = 0;
1702          loop {
1703            vec_dest = *(p);
1704            indx = indx + 1;
1705          }
1706       */
1707
1708       vec_dest = vect_create_destination_var (scalar_dest, vectype);
1709       data_ref = vect_create_data_ref_ptr (stmt, bsi, NULL_TREE, &dummy, false);
1710       if (aligned_access_p (dr))
1711         data_ref = build_fold_indirect_ref (data_ref);
1712       else
1713         {
1714           int mis = DR_MISALIGNMENT (dr);
1715           tree tmis = (mis == -1 ? size_zero_node : size_int (mis));
1716           tmis = size_binop (MULT_EXPR, tmis, size_int(BITS_PER_UNIT));
1717           data_ref = build2 (MISALIGNED_INDIRECT_REF, vectype, data_ref, tmis);
1718         }
1719       new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, data_ref);
1720       new_temp = make_ssa_name (vec_dest, new_stmt);
1721       TREE_OPERAND (new_stmt, 0) = new_temp;
1722       vect_finish_stmt_generation (stmt, new_stmt, bsi);
1723       copy_virtual_operands (new_stmt, stmt);
1724     }
1725   else if (alignment_support_cheme == dr_unaligned_software_pipeline)
1726     {
1727       /* Create:
1728          p1 = initial_addr;
1729          msq_init = *(floor(p1))
1730          p2 = initial_addr + VS - 1;
1731          magic = have_builtin ? builtin_result : initial_address;
1732          indx = 0;
1733          loop {
1734            p2' = p2 + indx * vectype_size
1735            lsq = *(floor(p2'))
1736            vec_dest = realign_load (msq, lsq, magic)
1737            indx = indx + 1;
1738            msq = lsq;
1739          }
1740       */
1741
1742       tree offset;
1743       tree magic;
1744       tree phi_stmt;
1745       tree msq_init;
1746       tree msq, lsq;
1747       tree dataref_ptr;
1748       tree params;
1749
1750       /* <1> Create msq_init = *(floor(p1)) in the loop preheader  */
1751       vec_dest = vect_create_destination_var (scalar_dest, vectype);
1752       data_ref = vect_create_data_ref_ptr (stmt, bsi, NULL_TREE,
1753                                            &init_addr, true);
1754       data_ref = build1 (ALIGN_INDIRECT_REF, vectype, data_ref);
1755       new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, data_ref);
1756       new_temp = make_ssa_name (vec_dest, new_stmt);
1757       TREE_OPERAND (new_stmt, 0) = new_temp;
1758       new_bb = bsi_insert_on_edge_immediate (pe, new_stmt);
1759       gcc_assert (!new_bb);
1760       msq_init = TREE_OPERAND (new_stmt, 0);
1761       copy_virtual_operands (new_stmt, stmt);
1762       update_vuses_to_preheader (new_stmt, loop);
1763
1764
1765       /* <2> Create lsq = *(floor(p2')) in the loop  */
1766       offset = build_int_cst (integer_type_node,
1767                               TYPE_VECTOR_SUBPARTS (vectype));
1768       offset = int_const_binop (MINUS_EXPR, offset, integer_one_node, 1);
1769       vec_dest = vect_create_destination_var (scalar_dest, vectype);
1770       dataref_ptr = vect_create_data_ref_ptr (stmt, bsi, offset, &dummy, false);
1771       data_ref = build1 (ALIGN_INDIRECT_REF, vectype, dataref_ptr);
1772       new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, data_ref);
1773       new_temp = make_ssa_name (vec_dest, new_stmt);
1774       TREE_OPERAND (new_stmt, 0) = new_temp;
1775       vect_finish_stmt_generation (stmt, new_stmt, bsi);
1776       lsq = TREE_OPERAND (new_stmt, 0);
1777       copy_virtual_operands (new_stmt, stmt);
1778
1779
1780       /* <3> */
1781       if (targetm.vectorize.builtin_mask_for_load)
1782         {
1783           /* Create permutation mask, if required, in loop preheader.  */
1784           tree builtin_decl;
1785           params = build_tree_list (NULL_TREE, init_addr);
1786           vec_dest = vect_create_destination_var (scalar_dest, vectype);
1787           builtin_decl = targetm.vectorize.builtin_mask_for_load ();
1788           new_stmt = build_function_call_expr (builtin_decl, params);
1789           new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, new_stmt);
1790           new_temp = make_ssa_name (vec_dest, new_stmt);
1791           TREE_OPERAND (new_stmt, 0) = new_temp;
1792           new_bb = bsi_insert_on_edge_immediate (pe, new_stmt);
1793           gcc_assert (!new_bb);
1794           magic = TREE_OPERAND (new_stmt, 0);
1795
1796           /* The result of the CALL_EXPR to this builtin is determined from
1797              the value of the parameter and no global variables are touched
1798              which makes the builtin a "const" function.  Requiring the
1799              builtin to have the "const" attribute makes it unnecessary
1800              to call mark_call_clobbered_vars_to_rename.  */
1801           gcc_assert (TREE_READONLY (builtin_decl));
1802         }
1803       else
1804         {
1805           /* Use current address instead of init_addr for reduced reg pressure.
1806            */
1807           magic = dataref_ptr;
1808         }
1809
1810
1811       /* <4> Create msq = phi <msq_init, lsq> in loop  */
1812       vec_dest = vect_create_destination_var (scalar_dest, vectype);
1813       msq = make_ssa_name (vec_dest, NULL_TREE);
1814       phi_stmt = create_phi_node (msq, loop->header); /* CHECKME */
1815       SSA_NAME_DEF_STMT (msq) = phi_stmt;
1816       add_phi_arg (phi_stmt, msq_init, loop_preheader_edge (loop));
1817       add_phi_arg (phi_stmt, lsq, loop_latch_edge (loop));
1818
1819
1820       /* <5> Create <vec_dest = realign_load (msq, lsq, magic)> in loop  */
1821       vec_dest = vect_create_destination_var (scalar_dest, vectype);
1822       new_stmt = build3 (REALIGN_LOAD_EXPR, vectype, msq, lsq, magic);
1823       new_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, new_stmt);
1824       new_temp = make_ssa_name (vec_dest, new_stmt);
1825       TREE_OPERAND (new_stmt, 0) = new_temp;
1826       vect_finish_stmt_generation (stmt, new_stmt, bsi);
1827     }
1828   else
1829     gcc_unreachable ();
1830
1831   *vec_stmt = new_stmt;
1832   return true;
1833 }
1834
1835
1836 /* Function vectorizable_live_operation.
1837
1838    STMT computes a value that is used outside the loop. Check if
1839    it can be supported.  */
1840
1841 bool
1842 vectorizable_live_operation (tree stmt,
1843                              block_stmt_iterator *bsi ATTRIBUTE_UNUSED,
1844                              tree *vec_stmt ATTRIBUTE_UNUSED)
1845 {
1846   tree operation;
1847   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1848   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1849   int i;
1850   enum tree_code code;
1851   int op_type;
1852   tree op;
1853   tree def, def_stmt;
1854   enum vect_def_type dt;
1855
1856   if (!STMT_VINFO_LIVE_P (stmt_info))
1857     return false;
1858
1859   if (TREE_CODE (stmt) != MODIFY_EXPR)
1860     return false;
1861
1862   if (TREE_CODE (TREE_OPERAND (stmt, 0)) != SSA_NAME)
1863     return false;
1864
1865   operation = TREE_OPERAND (stmt, 1);
1866   code = TREE_CODE (operation);
1867
1868   op_type = TREE_CODE_LENGTH (code);
1869
1870   /* FORNOW: support only if all uses are invariant. This means
1871      that the scalar operations can remain in place, unvectorized.
1872      The original last scalar value that they compute will be used.  */
1873
1874   for (i = 0; i < op_type; i++)
1875     {
1876       op = TREE_OPERAND (operation, i);
1877       if (!vect_is_simple_use (op, loop_vinfo, &def_stmt, &def, &dt))
1878         {
1879           if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
1880             fprintf (vect_dump, "use not simple.");
1881           return false;
1882         }
1883
1884       if (dt != vect_invariant_def && dt != vect_constant_def)
1885         return false;
1886     }
1887
1888   /* No transformation is required for the cases we currently support.  */
1889   return true;
1890 }
1891
1892
1893 /* Function vect_is_simple_cond.
1894
1895    Input:
1896    LOOP - the loop that is being vectorized.
1897    COND - Condition that is checked for simple use.
1898
1899    Returns whether a COND can be vectorized.  Checks whether
1900    condition operands are supportable using vec_is_simple_use.  */
1901
1902 static bool
1903 vect_is_simple_cond (tree cond, loop_vec_info loop_vinfo)
1904 {
1905   tree lhs, rhs;
1906   tree def;
1907   enum vect_def_type dt;
1908
1909   if (!COMPARISON_CLASS_P (cond))
1910     return false;
1911
1912   lhs = TREE_OPERAND (cond, 0);
1913   rhs = TREE_OPERAND (cond, 1);
1914
1915   if (TREE_CODE (lhs) == SSA_NAME)
1916     {
1917       tree lhs_def_stmt = SSA_NAME_DEF_STMT (lhs);
1918       if (!vect_is_simple_use (lhs, loop_vinfo, &lhs_def_stmt, &def, &dt))
1919         return false;
1920     }
1921   else if (TREE_CODE (lhs) != INTEGER_CST && TREE_CODE (lhs) != REAL_CST)
1922     return false;
1923
1924   if (TREE_CODE (rhs) == SSA_NAME)
1925     {
1926       tree rhs_def_stmt = SSA_NAME_DEF_STMT (rhs);
1927       if (!vect_is_simple_use (rhs, loop_vinfo, &rhs_def_stmt, &def, &dt))
1928         return false;
1929     }
1930   else if (TREE_CODE (rhs) != INTEGER_CST  && TREE_CODE (rhs) != REAL_CST)
1931     return false;
1932
1933   return true;
1934 }
1935
1936 /* vectorizable_condition.
1937
1938    Check if STMT is conditional modify expression that can be vectorized.
1939    If VEC_STMT is also passed, vectorize the STMT: create a vectorized
1940    stmt using VEC_COND_EXPR  to replace it, put it in VEC_STMT, and insert it
1941    at BSI.
1942
1943    Return FALSE if not a vectorizable STMT, TRUE otherwise.  */
1944
1945 bool
1946 vectorizable_condition (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt)
1947 {
1948   tree scalar_dest = NULL_TREE;
1949   tree vec_dest = NULL_TREE;
1950   tree op = NULL_TREE;
1951   tree cond_expr, then_clause, else_clause;
1952   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
1953   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
1954   tree vec_cond_lhs, vec_cond_rhs, vec_then_clause, vec_else_clause;
1955   tree vec_compare, vec_cond_expr;
1956   tree new_temp;
1957   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
1958   enum machine_mode vec_mode;
1959   tree def;
1960   enum vect_def_type dt;
1961
1962   if (!STMT_VINFO_RELEVANT_P (stmt_info))
1963     return false;
1964
1965   gcc_assert (STMT_VINFO_DEF_TYPE (stmt_info) == vect_loop_def);
1966
1967   if (STMT_VINFO_LIVE_P (stmt_info))
1968     {
1969       /* FORNOW: not yet supported.  */
1970       if (vect_print_dump_info (REPORT_DETAILS, LOOP_LOC (loop_vinfo)))
1971         fprintf (vect_dump, "value used after loop.");
1972       return false;
1973     }
1974
1975   if (TREE_CODE (stmt) != MODIFY_EXPR)
1976     return false;
1977
1978   op = TREE_OPERAND (stmt, 1);
1979
1980   if (TREE_CODE (op) != COND_EXPR)
1981     return false;
1982
1983   cond_expr = TREE_OPERAND (op, 0);
1984   then_clause = TREE_OPERAND (op, 1);
1985   else_clause = TREE_OPERAND (op, 2);
1986
1987   if (!vect_is_simple_cond (cond_expr, loop_vinfo))
1988     return false;
1989
1990   if (TREE_CODE (then_clause) == SSA_NAME)
1991     {
1992       tree then_def_stmt = SSA_NAME_DEF_STMT (then_clause);
1993       if (!vect_is_simple_use (then_clause, loop_vinfo,
1994                                &then_def_stmt, &def, &dt))
1995         return false;
1996     }
1997   else if (TREE_CODE (then_clause) != INTEGER_CST
1998            && TREE_CODE (then_clause) != REAL_CST)
1999     return false;
2000
2001   if (TREE_CODE (else_clause) == SSA_NAME)
2002     {
2003       tree else_def_stmt = SSA_NAME_DEF_STMT (else_clause);
2004       if (!vect_is_simple_use (else_clause, loop_vinfo,
2005                                &else_def_stmt, &def, &dt))
2006         return false;
2007     }
2008   else if (TREE_CODE (else_clause) != INTEGER_CST
2009            && TREE_CODE (else_clause) != REAL_CST)
2010     return false;
2011
2012
2013   vec_mode = TYPE_MODE (vectype);
2014
2015   if (!vec_stmt)
2016     {
2017       STMT_VINFO_TYPE (stmt_info) = condition_vec_info_type;
2018       return expand_vec_cond_expr_p (op, vec_mode);
2019     }
2020
2021   /* Transform */
2022
2023   /* Handle def.  */
2024   scalar_dest = TREE_OPERAND (stmt, 0);
2025   vec_dest = vect_create_destination_var (scalar_dest, vectype);
2026
2027   /* Handle cond expr.  */
2028   vec_cond_lhs =
2029     vect_get_vec_def_for_operand (TREE_OPERAND (cond_expr, 0), stmt, NULL);
2030   vec_cond_rhs =
2031     vect_get_vec_def_for_operand (TREE_OPERAND (cond_expr, 1), stmt, NULL);
2032   vec_then_clause = vect_get_vec_def_for_operand (then_clause, stmt, NULL);
2033   vec_else_clause = vect_get_vec_def_for_operand (else_clause, stmt, NULL);
2034
2035   /* Arguments are ready. create the new vector stmt.  */
2036   vec_compare = build2 (TREE_CODE (cond_expr), vectype,
2037                         vec_cond_lhs, vec_cond_rhs);
2038   vec_cond_expr = build (VEC_COND_EXPR, vectype,
2039                          vec_compare, vec_then_clause, vec_else_clause);
2040
2041   *vec_stmt = build2 (MODIFY_EXPR, vectype, vec_dest, vec_cond_expr);
2042   new_temp = make_ssa_name (vec_dest, *vec_stmt);
2043   TREE_OPERAND (*vec_stmt, 0) = new_temp;
2044   vect_finish_stmt_generation (stmt, *vec_stmt, bsi);
2045
2046   return true;
2047 }
2048
2049 /* Function vect_transform_stmt.
2050
2051    Create a vectorized stmt to replace STMT, and insert it at BSI.  */
2052
2053 bool
2054 vect_transform_stmt (tree stmt, block_stmt_iterator *bsi)
2055 {
2056   bool is_store = false;
2057   tree vec_stmt = NULL_TREE;
2058   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
2059   bool done;
2060
2061   if (STMT_VINFO_RELEVANT_P (stmt_info))
2062     {
2063       switch (STMT_VINFO_TYPE (stmt_info))
2064       {
2065       case op_vec_info_type:
2066         done = vectorizable_operation (stmt, bsi, &vec_stmt);
2067         gcc_assert (done);
2068         break;
2069
2070       case assignment_vec_info_type:
2071         done = vectorizable_assignment (stmt, bsi, &vec_stmt);
2072         gcc_assert (done);
2073         break;
2074
2075       case load_vec_info_type:
2076         done = vectorizable_load (stmt, bsi, &vec_stmt);
2077         gcc_assert (done);
2078         break;
2079
2080       case store_vec_info_type:
2081         done = vectorizable_store (stmt, bsi, &vec_stmt);
2082         gcc_assert (done);
2083         is_store = true;
2084         break;
2085
2086       case condition_vec_info_type:
2087         done = vectorizable_condition (stmt, bsi, &vec_stmt);
2088         gcc_assert (done);
2089         break;
2090
2091       default:
2092         if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2093           fprintf (vect_dump, "stmt not supported.");
2094         gcc_unreachable ();
2095       }
2096
2097       STMT_VINFO_VEC_STMT (stmt_info) = vec_stmt;
2098     }
2099
2100   if (STMT_VINFO_LIVE_P (stmt_info))
2101     {
2102       switch (STMT_VINFO_TYPE (stmt_info))
2103       {
2104       case reduc_vec_info_type:
2105         done = vectorizable_reduction (stmt, bsi, &vec_stmt);
2106         gcc_assert (done);
2107         break;
2108
2109       default:
2110         done = vectorizable_live_operation (stmt, bsi, &vec_stmt);
2111         gcc_assert (done);
2112       }
2113
2114       if (vec_stmt)
2115         {
2116           gcc_assert (!STMT_VINFO_VEC_STMT (stmt_info));
2117           STMT_VINFO_VEC_STMT (stmt_info) = vec_stmt;
2118         }
2119     }
2120
2121   return is_store;
2122 }
2123
2124
2125 /* This function builds ni_name = number of iterations loop executes
2126    on the loop preheader.  */
2127
2128 static tree
2129 vect_build_loop_niters (loop_vec_info loop_vinfo)
2130 {
2131   tree ni_name, stmt, var;
2132   edge pe;
2133   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2134   tree ni = unshare_expr (LOOP_VINFO_NITERS (loop_vinfo));
2135
2136   var = create_tmp_var (TREE_TYPE (ni), "niters");
2137   add_referenced_tmp_var (var);
2138   ni_name = force_gimple_operand (ni, &stmt, false, var);
2139
2140   pe = loop_preheader_edge (loop);
2141   if (stmt)
2142     {
2143       basic_block new_bb = bsi_insert_on_edge_immediate (pe, stmt);
2144       gcc_assert (!new_bb);
2145     }
2146
2147   return ni_name;
2148 }
2149
2150
2151 /* This function generates the following statements:
2152
2153  ni_name = number of iterations loop executes
2154  ratio = ni_name / vf
2155  ratio_mult_vf_name = ratio * vf
2156
2157  and places them at the loop preheader edge.  */
2158
2159 static void
2160 vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo,
2161                                  tree *ni_name_ptr,
2162                                  tree *ratio_mult_vf_name_ptr,
2163                                  tree *ratio_name_ptr)
2164 {
2165
2166   edge pe;
2167   basic_block new_bb;
2168   tree stmt, ni_name;
2169   tree var;
2170   tree ratio_name;
2171   tree ratio_mult_vf_name;
2172   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2173   tree ni = LOOP_VINFO_NITERS (loop_vinfo);
2174   int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
2175   tree log_vf = build_int_cst (unsigned_type_node, exact_log2 (vf));
2176
2177   pe = loop_preheader_edge (loop);
2178
2179   /* Generate temporary variable that contains
2180      number of iterations loop executes.  */
2181
2182   ni_name = vect_build_loop_niters (loop_vinfo);
2183
2184   /* Create: ratio = ni >> log2(vf) */
2185
2186   var = create_tmp_var (TREE_TYPE (ni), "bnd");
2187   add_referenced_tmp_var (var);
2188   ratio_name = make_ssa_name (var, NULL_TREE);
2189   stmt = build2 (MODIFY_EXPR, void_type_node, ratio_name,
2190            build2 (RSHIFT_EXPR, TREE_TYPE (ni_name), ni_name, log_vf));
2191   SSA_NAME_DEF_STMT (ratio_name) = stmt;
2192
2193   pe = loop_preheader_edge (loop);
2194   new_bb = bsi_insert_on_edge_immediate (pe, stmt);
2195   gcc_assert (!new_bb);
2196
2197   /* Create: ratio_mult_vf = ratio << log2 (vf).  */
2198
2199   var = create_tmp_var (TREE_TYPE (ni), "ratio_mult_vf");
2200   add_referenced_tmp_var (var);
2201   ratio_mult_vf_name = make_ssa_name (var, NULL_TREE);
2202   stmt = build2 (MODIFY_EXPR, void_type_node, ratio_mult_vf_name,
2203            build2 (LSHIFT_EXPR, TREE_TYPE (ratio_name), ratio_name, log_vf));
2204   SSA_NAME_DEF_STMT (ratio_mult_vf_name) = stmt;
2205
2206   pe = loop_preheader_edge (loop);
2207   new_bb = bsi_insert_on_edge_immediate (pe, stmt);
2208   gcc_assert (!new_bb);
2209
2210   *ni_name_ptr = ni_name;
2211   *ratio_mult_vf_name_ptr = ratio_mult_vf_name;
2212   *ratio_name_ptr = ratio_name;
2213
2214   return;
2215 }
2216
2217
2218 /* Function update_vuses_to_preheader.
2219
2220    Input:
2221    STMT - a statement with potential VUSEs.
2222    LOOP - the loop whose preheader will contain STMT.
2223
2224    It's possible to vectorize a loop even though an SSA_NAME from a VUSE
2225    appears to be defined in a V_MAY_DEF in another statement in a loop.
2226    One such case is when the VUSE is at the dereference of a __restricted__
2227    pointer in a load and the V_MAY_DEF is at the dereference of a different
2228    __restricted__ pointer in a store.  Vectorization may result in
2229    copy_virtual_uses being called to copy the problematic VUSE to a new
2230    statement that is being inserted in the loop preheader.  This procedure
2231    is called to change the SSA_NAME in the new statement's VUSE from the
2232    SSA_NAME updated in the loop to the related SSA_NAME available on the
2233    path entering the loop.
2234
2235    When this function is called, we have the following situation:
2236
2237         # vuse <name1>
2238         S1: vload
2239     do {
2240         # name1 = phi < name0 , name2>
2241
2242         # vuse <name1>
2243         S2: vload
2244
2245         # name2 = vdef <name1>
2246         S3: vstore
2247
2248     }while...
2249
2250    Stmt S1 was created in the loop preheader block as part of misaligned-load
2251    handling. This function fixes the name of the vuse of S1 from 'name1' to
2252    'name0'.  */
2253
2254 static void
2255 update_vuses_to_preheader (tree stmt, struct loop *loop)
2256 {
2257   basic_block header_bb = loop->header;
2258   edge preheader_e = loop_preheader_edge (loop);
2259   ssa_op_iter iter;
2260   use_operand_p use_p;
2261
2262   FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_VUSE)
2263     {
2264       tree ssa_name = USE_FROM_PTR (use_p);
2265       tree def_stmt = SSA_NAME_DEF_STMT (ssa_name);
2266       tree name_var = SSA_NAME_VAR (ssa_name);
2267       basic_block bb = bb_for_stmt (def_stmt);
2268
2269       /* For a use before any definitions, def_stmt is a NOP_EXPR.  */
2270       if (!IS_EMPTY_STMT (def_stmt)
2271           && flow_bb_inside_loop_p (loop, bb))
2272         {
2273           /* If the block containing the statement defining the SSA_NAME
2274              is in the loop then it's necessary to find the definition
2275              outside the loop using the PHI nodes of the header.  */
2276           tree phi;
2277           bool updated = false;
2278
2279           for (phi = phi_nodes (header_bb); phi; phi = TREE_CHAIN (phi))
2280             {
2281               if (SSA_NAME_VAR (PHI_RESULT (phi)) == name_var)
2282                 {
2283                   SET_USE (use_p, PHI_ARG_DEF (phi, preheader_e->dest_idx));
2284                   updated = true;
2285                   break;
2286                 }
2287             }
2288           gcc_assert (updated);
2289         }
2290     }
2291 }
2292
2293
2294 /*   Function vect_update_ivs_after_vectorizer.
2295
2296      "Advance" the induction variables of LOOP to the value they should take
2297      after the execution of LOOP.  This is currently necessary because the
2298      vectorizer does not handle induction variables that are used after the
2299      loop.  Such a situation occurs when the last iterations of LOOP are
2300      peeled, because:
2301      1. We introduced new uses after LOOP for IVs that were not originally used
2302         after LOOP: the IVs of LOOP are now used by an epilog loop.
2303      2. LOOP is going to be vectorized; this means that it will iterate N/VF
2304         times, whereas the loop IVs should be bumped N times.
2305
2306      Input:
2307      - LOOP - a loop that is going to be vectorized. The last few iterations
2308               of LOOP were peeled.
2309      - NITERS - the number of iterations that LOOP executes (before it is
2310                 vectorized). i.e, the number of times the ivs should be bumped.
2311      - UPDATE_E - a successor edge of LOOP->exit that is on the (only) path
2312                   coming out from LOOP on which there are uses of the LOOP ivs
2313                   (this is the path from LOOP->exit to epilog_loop->preheader).
2314
2315                   The new definitions of the ivs are placed in LOOP->exit.
2316                   The phi args associated with the edge UPDATE_E in the bb
2317                   UPDATE_E->dest are updated accordingly.
2318
2319      Assumption 1: Like the rest of the vectorizer, this function assumes
2320      a single loop exit that has a single predecessor.
2321
2322      Assumption 2: The phi nodes in the LOOP header and in update_bb are
2323      organized in the same order.
2324
2325      Assumption 3: The access function of the ivs is simple enough (see
2326      vect_can_advance_ivs_p).  This assumption will be relaxed in the future.
2327
2328      Assumption 4: Exactly one of the successors of LOOP exit-bb is on a path
2329      coming out of LOOP on which the ivs of LOOP are used (this is the path
2330      that leads to the epilog loop; other paths skip the epilog loop).  This
2331      path starts with the edge UPDATE_E, and its destination (denoted update_bb)
2332      needs to have its phis updated.
2333  */
2334
2335 static void
2336 vect_update_ivs_after_vectorizer (loop_vec_info loop_vinfo, tree niters,
2337                                   edge update_e)
2338 {
2339   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2340   basic_block exit_bb = loop->single_exit->dest;
2341   tree phi, phi1;
2342   basic_block update_bb = update_e->dest;
2343
2344   /* gcc_assert (vect_can_advance_ivs_p (loop_vinfo)); */
2345
2346   /* Make sure there exists a single-predecessor exit bb:  */
2347   gcc_assert (single_pred_p (exit_bb));
2348
2349   for (phi = phi_nodes (loop->header), phi1 = phi_nodes (update_bb);
2350        phi && phi1;
2351        phi = PHI_CHAIN (phi), phi1 = PHI_CHAIN (phi1))
2352     {
2353       tree access_fn = NULL;
2354       tree evolution_part;
2355       tree init_expr;
2356       tree step_expr;
2357       tree var, stmt, ni, ni_name;
2358       block_stmt_iterator last_bsi;
2359
2360       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2361         {
2362           fprintf (vect_dump, "vect_update_ivs_after_vectorizer: phi: ");
2363           print_generic_expr (vect_dump, phi, TDF_SLIM);
2364         }
2365
2366       /* Skip virtual phi's.  */
2367       if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
2368         {
2369           if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2370             fprintf (vect_dump, "virtual phi. skip.");
2371           continue;
2372         }
2373
2374       /* Skip reduction phis.  */
2375       if (STMT_VINFO_DEF_TYPE (vinfo_for_stmt (phi)) == vect_reduction_def)
2376         {
2377           if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2378             fprintf (vect_dump, "reduc phi. skip.");
2379           continue;
2380         }
2381
2382       access_fn = analyze_scalar_evolution (loop, PHI_RESULT (phi));
2383       gcc_assert (access_fn);
2384       evolution_part =
2385          unshare_expr (evolution_part_in_loop_num (access_fn, loop->num));
2386       gcc_assert (evolution_part != NULL_TREE);
2387
2388       /* FORNOW: We do not support IVs whose evolution function is a polynomial
2389          of degree >= 2 or exponential.  */
2390       gcc_assert (!tree_is_chrec (evolution_part));
2391
2392       step_expr = evolution_part;
2393       init_expr = unshare_expr (initial_condition_in_loop_num (access_fn,
2394                                                                loop->num));
2395
2396       ni = build2 (PLUS_EXPR, TREE_TYPE (init_expr),
2397                   build2 (MULT_EXPR, TREE_TYPE (niters),
2398                        niters, step_expr), init_expr);
2399
2400       var = create_tmp_var (TREE_TYPE (init_expr), "tmp");
2401       add_referenced_tmp_var (var);
2402
2403       ni_name = force_gimple_operand (ni, &stmt, false, var);
2404
2405       /* Insert stmt into exit_bb.  */
2406       last_bsi = bsi_last (exit_bb);
2407       if (stmt)
2408         bsi_insert_before (&last_bsi, stmt, BSI_SAME_STMT);
2409
2410       /* Fix phi expressions in the successor bb.  */
2411       SET_PHI_ARG_DEF (phi1, update_e->dest_idx, ni_name);
2412     }
2413 }
2414
2415
2416 /* Function vect_do_peeling_for_loop_bound
2417
2418    Peel the last iterations of the loop represented by LOOP_VINFO.
2419    The peeled iterations form a new epilog loop.  Given that the loop now
2420    iterates NITERS times, the new epilog loop iterates
2421    NITERS % VECTORIZATION_FACTOR times.
2422
2423    The original loop will later be made to iterate
2424    NITERS / VECTORIZATION_FACTOR times (this value is placed into RATIO).  */
2425
2426 static void
2427 vect_do_peeling_for_loop_bound (loop_vec_info loop_vinfo, tree *ratio,
2428                                 struct loops *loops)
2429 {
2430   tree ni_name, ratio_mult_vf_name;
2431   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2432   struct loop *new_loop;
2433   edge update_e;
2434   basic_block preheader;
2435   int loop_num;
2436
2437   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2438     fprintf (vect_dump, "=== vect_do_peeling_for_loop_bound ===");
2439
2440   initialize_original_copy_tables ();
2441
2442   /* Generate the following variables on the preheader of original loop:
2443
2444      ni_name = number of iteration the original loop executes
2445      ratio = ni_name / vf
2446      ratio_mult_vf_name = ratio * vf  */
2447   vect_generate_tmps_on_preheader (loop_vinfo, &ni_name,
2448                                    &ratio_mult_vf_name, ratio);
2449
2450   loop_num  = loop->num;
2451   new_loop = slpeel_tree_peel_loop_to_edge (loop, loops, loop->single_exit,
2452                                             ratio_mult_vf_name, ni_name, false);
2453   gcc_assert (new_loop);
2454   gcc_assert (loop_num == loop->num);
2455 #ifdef ENABLE_CHECKING
2456   slpeel_verify_cfg_after_peeling (loop, new_loop);
2457 #endif
2458
2459   /* A guard that controls whether the new_loop is to be executed or skipped
2460      is placed in LOOP->exit.  LOOP->exit therefore has two successors - one
2461      is the preheader of NEW_LOOP, where the IVs from LOOP are used.  The other
2462      is a bb after NEW_LOOP, where these IVs are not used.  Find the edge that
2463      is on the path where the LOOP IVs are used and need to be updated.  */
2464
2465   preheader = loop_preheader_edge (new_loop)->src;
2466   if (EDGE_PRED (preheader, 0)->src == loop->single_exit->dest)
2467     update_e = EDGE_PRED (preheader, 0);
2468   else
2469     update_e = EDGE_PRED (preheader, 1);
2470
2471   /* Update IVs of original loop as if they were advanced
2472      by ratio_mult_vf_name steps.  */
2473   vect_update_ivs_after_vectorizer (loop_vinfo, ratio_mult_vf_name, update_e);
2474
2475   /* After peeling we have to reset scalar evolution analyzer.  */
2476   scev_reset ();
2477
2478   free_original_copy_tables ();
2479 }
2480
2481
2482 /* Function vect_gen_niters_for_prolog_loop
2483
2484    Set the number of iterations for the loop represented by LOOP_VINFO
2485    to the minimum between LOOP_NITERS (the original iteration count of the loop)
2486    and the misalignment of DR - the data reference recorded in
2487    LOOP_VINFO_UNALIGNED_DR (LOOP_VINFO).  As a result, after the execution of
2488    this loop, the data reference DR will refer to an aligned location.
2489
2490    The following computation is generated:
2491
2492    If the misalignment of DR is known at compile time:
2493      addr_mis = int mis = DR_MISALIGNMENT (dr);
2494    Else, compute address misalignment in bytes:
2495      addr_mis = addr & (vectype_size - 1)
2496
2497    prolog_niters = min ( LOOP_NITERS , (VF - addr_mis/elem_size)&(VF-1) )
2498
2499    (elem_size = element type size; an element is the scalar element
2500         whose type is the inner type of the vectype)  */
2501
2502 static tree
2503 vect_gen_niters_for_prolog_loop (loop_vec_info loop_vinfo, tree loop_niters)
2504 {
2505   struct data_reference *dr = LOOP_VINFO_UNALIGNED_DR (loop_vinfo);
2506   int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
2507   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2508   tree var, stmt;
2509   tree iters, iters_name;
2510   edge pe;
2511   basic_block new_bb;
2512   tree dr_stmt = DR_STMT (dr);
2513   stmt_vec_info stmt_info = vinfo_for_stmt (dr_stmt);
2514   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
2515   int vectype_align = TYPE_ALIGN (vectype) / BITS_PER_UNIT;
2516   tree vf_minus_1 = build_int_cst (unsigned_type_node, vf - 1);
2517   tree niters_type = TREE_TYPE (loop_niters);
2518
2519   pe = loop_preheader_edge (loop);
2520
2521   if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) > 0)
2522     {
2523       int byte_misalign = LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo);
2524       int element_size = vectype_align/vf;
2525       int elem_misalign = byte_misalign / element_size;
2526
2527       if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2528         fprintf (vect_dump, "known alignment = %d.", byte_misalign);
2529       iters = build_int_cst (niters_type, (vf - elem_misalign)&(vf-1));
2530     }
2531   else
2532     {
2533       tree new_stmts = NULL_TREE;
2534       tree start_addr =
2535         vect_create_addr_base_for_vector_ref (dr_stmt, &new_stmts, NULL_TREE);
2536       tree ptr_type = TREE_TYPE (start_addr);
2537       tree size = TYPE_SIZE (ptr_type);
2538       tree type = lang_hooks.types.type_for_size (tree_low_cst (size, 1), 1);
2539       tree vectype_size_minus_1 = build_int_cst (type, vectype_align - 1);
2540       tree elem_size_log =
2541         build_int_cst (unsigned_type_node, exact_log2 (vectype_align/vf));
2542       tree vf_tree = build_int_cst (unsigned_type_node, vf);
2543       tree byte_misalign;
2544       tree elem_misalign;
2545
2546       new_bb = bsi_insert_on_edge_immediate (pe, new_stmts);
2547       gcc_assert (!new_bb);
2548
2549       /* Create:  byte_misalign = addr & (vectype_size - 1)  */
2550       byte_misalign =
2551         build2 (BIT_AND_EXPR, type, start_addr, vectype_size_minus_1);
2552
2553       /* Create:  elem_misalign = byte_misalign / element_size  */
2554       elem_misalign =
2555         build2 (RSHIFT_EXPR, unsigned_type_node, byte_misalign, elem_size_log);
2556
2557       /* Create:  (niters_type) (VF - elem_misalign)&(VF - 1)  */
2558       iters = build2 (MINUS_EXPR, unsigned_type_node, vf_tree, elem_misalign);
2559       iters = build2 (BIT_AND_EXPR, unsigned_type_node, iters, vf_minus_1);
2560       iters = fold_convert (niters_type, iters);
2561     }
2562
2563   /* Create:  prolog_loop_niters = min (iters, loop_niters) */
2564   /* If the loop bound is known at compile time we already verified that it is
2565      greater than vf; since the misalignment ('iters') is at most vf, there's
2566      no need to generate the MIN_EXPR in this case.  */
2567   if (TREE_CODE (loop_niters) != INTEGER_CST)
2568     iters = build2 (MIN_EXPR, niters_type, iters, loop_niters);
2569
2570   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2571     {
2572       fprintf (vect_dump, "niters for prolog loop: ");
2573       print_generic_expr (vect_dump, iters, TDF_SLIM);
2574     }
2575
2576   var = create_tmp_var (niters_type, "prolog_loop_niters");
2577   add_referenced_tmp_var (var);
2578   iters_name = force_gimple_operand (iters, &stmt, false, var);
2579
2580   /* Insert stmt on loop preheader edge.  */
2581   if (stmt)
2582     {
2583       basic_block new_bb = bsi_insert_on_edge_immediate (pe, stmt);
2584       gcc_assert (!new_bb);
2585     }
2586
2587   return iters_name;
2588 }
2589
2590
2591 /* Function vect_update_init_of_dr
2592
2593    NITERS iterations were peeled from LOOP.  DR represents a data reference
2594    in LOOP.  This function updates the information recorded in DR to
2595    account for the fact that the first NITERS iterations had already been
2596    executed.  Specifically, it updates the OFFSET field of stmt_info.  */
2597
2598 static void
2599 vect_update_init_of_dr (struct data_reference *dr, tree niters)
2600 {
2601   stmt_vec_info stmt_info = vinfo_for_stmt (DR_STMT (dr));
2602   tree offset = STMT_VINFO_VECT_INIT_OFFSET (stmt_info);
2603
2604   niters = fold (build2 (MULT_EXPR, TREE_TYPE (niters), niters,
2605                          STMT_VINFO_VECT_STEP (stmt_info)));
2606   offset = fold (build2 (PLUS_EXPR, TREE_TYPE (offset), offset, niters));
2607   STMT_VINFO_VECT_INIT_OFFSET (stmt_info) = offset;
2608 }
2609
2610
2611 /* Function vect_update_inits_of_drs
2612
2613    NITERS iterations were peeled from the loop represented by LOOP_VINFO.
2614    This function updates the information recorded for the data references in
2615    the loop to account for the fact that the first NITERS iterations had
2616    already been executed.  Specifically, it updates the initial_condition of the
2617    access_function of all the data_references in the loop.  */
2618
2619 static void
2620 vect_update_inits_of_drs (loop_vec_info loop_vinfo, tree niters)
2621 {
2622   unsigned int i;
2623   varray_type loop_write_datarefs = LOOP_VINFO_DATAREF_WRITES (loop_vinfo);
2624   varray_type loop_read_datarefs = LOOP_VINFO_DATAREF_READS (loop_vinfo);
2625
2626   if (vect_dump && (dump_flags & TDF_DETAILS))
2627     fprintf (vect_dump, "=== vect_update_inits_of_dr ===");
2628
2629   for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_write_datarefs); i++)
2630     {
2631       struct data_reference *dr = VARRAY_GENERIC_PTR (loop_write_datarefs, i);
2632       vect_update_init_of_dr (dr, niters);
2633     }
2634
2635   for (i = 0; i < VARRAY_ACTIVE_SIZE (loop_read_datarefs); i++)
2636     {
2637       struct data_reference *dr = VARRAY_GENERIC_PTR (loop_read_datarefs, i);
2638       vect_update_init_of_dr (dr, niters);
2639     }
2640 }
2641
2642
2643 /* Function vect_do_peeling_for_alignment
2644
2645    Peel the first 'niters' iterations of the loop represented by LOOP_VINFO.
2646    'niters' is set to the misalignment of one of the data references in the
2647    loop, thereby forcing it to refer to an aligned location at the beginning
2648    of the execution of this loop.  The data reference for which we are
2649    peeling is recorded in LOOP_VINFO_UNALIGNED_DR.  */
2650
2651 static void
2652 vect_do_peeling_for_alignment (loop_vec_info loop_vinfo, struct loops *loops)
2653 {
2654   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2655   tree niters_of_prolog_loop, ni_name;
2656   tree n_iters;
2657   struct loop *new_loop;
2658
2659   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2660     fprintf (vect_dump, "=== vect_do_peeling_for_alignment ===");
2661
2662   initialize_original_copy_tables ();
2663
2664   ni_name = vect_build_loop_niters (loop_vinfo);
2665   niters_of_prolog_loop = vect_gen_niters_for_prolog_loop (loop_vinfo, ni_name);
2666
2667   /* Peel the prolog loop and iterate it niters_of_prolog_loop.  */
2668   new_loop =
2669         slpeel_tree_peel_loop_to_edge (loop, loops, loop_preheader_edge (loop),
2670                                        niters_of_prolog_loop, ni_name, true);
2671   gcc_assert (new_loop);
2672 #ifdef ENABLE_CHECKING
2673   slpeel_verify_cfg_after_peeling (new_loop, loop);
2674 #endif
2675
2676   /* Update number of times loop executes.  */
2677   n_iters = LOOP_VINFO_NITERS (loop_vinfo);
2678   LOOP_VINFO_NITERS (loop_vinfo) = fold (build2 (MINUS_EXPR,
2679                 TREE_TYPE (n_iters), n_iters, niters_of_prolog_loop));
2680
2681   /* Update the init conditions of the access functions of all data refs.  */
2682   vect_update_inits_of_drs (loop_vinfo, niters_of_prolog_loop);
2683
2684   /* After peeling we have to reset scalar evolution analyzer.  */
2685   scev_reset ();
2686
2687   free_original_copy_tables ();
2688 }
2689
2690
2691 /* Function vect_transform_loop.
2692
2693    The analysis phase has determined that the loop is vectorizable.
2694    Vectorize the loop - created vectorized stmts to replace the scalar
2695    stmts in the loop, and update the loop exit condition.  */
2696
2697 void
2698 vect_transform_loop (loop_vec_info loop_vinfo,
2699                      struct loops *loops ATTRIBUTE_UNUSED)
2700 {
2701   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
2702   basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
2703   int nbbs = loop->num_nodes;
2704   block_stmt_iterator si;
2705   int i;
2706   tree ratio = NULL;
2707   int vectorization_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
2708
2709   if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2710     fprintf (vect_dump, "=== vec_transform_loop ===");
2711
2712   /* Peel the loop if there are data refs with unknown alignment.
2713      Only one data ref with unknown store is allowed.  */
2714
2715   if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo))
2716     vect_do_peeling_for_alignment (loop_vinfo, loops);
2717
2718   /* If the loop has a symbolic number of iterations 'n' (i.e. it's not a
2719      compile time constant), or it is a constant that doesn't divide by the
2720      vectorization factor, then an epilog loop needs to be created.
2721      We therefore duplicate the loop: the original loop will be vectorized,
2722      and will compute the first (n/VF) iterations. The second copy of the loop
2723      will remain scalar and will compute the remaining (n%VF) iterations.
2724      (VF is the vectorization factor).  */
2725
2726   if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
2727       || (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
2728           && LOOP_VINFO_INT_NITERS (loop_vinfo) % vectorization_factor != 0))
2729     vect_do_peeling_for_loop_bound (loop_vinfo, &ratio, loops);
2730   else
2731     ratio = build_int_cst (TREE_TYPE (LOOP_VINFO_NITERS (loop_vinfo)),
2732                 LOOP_VINFO_INT_NITERS (loop_vinfo) / vectorization_factor);
2733
2734   /* 1) Make sure the loop header has exactly two entries
2735      2) Make sure we have a preheader basic block.  */
2736
2737   gcc_assert (EDGE_COUNT (loop->header->preds) == 2);
2738
2739   loop_split_edge_with (loop_preheader_edge (loop), NULL);
2740
2741
2742   /* FORNOW: the vectorizer supports only loops which body consist
2743      of one basic block (header + empty latch). When the vectorizer will
2744      support more involved loop forms, the order by which the BBs are
2745      traversed need to be reconsidered.  */
2746
2747   for (i = 0; i < nbbs; i++)
2748     {
2749       basic_block bb = bbs[i];
2750
2751       for (si = bsi_start (bb); !bsi_end_p (si);)
2752         {
2753           tree stmt = bsi_stmt (si);
2754           stmt_vec_info stmt_info;
2755           bool is_store;
2756
2757           if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2758             {
2759               fprintf (vect_dump, "------>vectorizing statement: ");
2760               print_generic_expr (vect_dump, stmt, TDF_SLIM);
2761             }
2762           stmt_info = vinfo_for_stmt (stmt);
2763           gcc_assert (stmt_info);
2764           if (!STMT_VINFO_RELEVANT_P (stmt_info)
2765               && !STMT_VINFO_LIVE_P (stmt_info))
2766             {
2767               bsi_next (&si);
2768               continue;
2769             }
2770           /* FORNOW: Verify that all stmts operate on the same number of
2771                      units and no inner unrolling is necessary.  */
2772           gcc_assert
2773                 (TYPE_VECTOR_SUBPARTS (STMT_VINFO_VECTYPE (stmt_info))
2774                  == vectorization_factor);
2775
2776           /* -------- vectorize statement ------------ */
2777           if (vect_print_dump_info (REPORT_DETAILS, UNKNOWN_LOC))
2778             fprintf (vect_dump, "transform statement.");
2779
2780           is_store = vect_transform_stmt (stmt, &si);
2781           if (is_store)
2782             {
2783               /* Free the attached stmt_vec_info and remove the stmt.  */
2784               stmt_ann_t ann = stmt_ann (stmt);
2785               free (stmt_info);
2786               set_stmt_info ((tree_ann_t)ann, NULL);
2787               bsi_remove (&si);
2788               continue;
2789             }
2790
2791           bsi_next (&si);
2792         }                       /* stmts in BB */
2793     }                           /* BBs in loop */
2794
2795   slpeel_make_loop_iterate_ntimes (loop, ratio);
2796
2797   /* The memory tags and pointers in vectorized statements need to
2798      have their SSA forms updated.  FIXME, why can't this be delayed
2799      until all the loops have been transformed?  */
2800   update_ssa (TODO_update_ssa);
2801
2802   if (vect_print_dump_info (REPORT_VECTORIZED_LOOPS, LOOP_LOC (loop_vinfo)))
2803     fprintf (vect_dump, "LOOP VECTORIZED.");
2804 }