gcc/tree-vect-patterns.c

   1 /* Analysis Utilities for Loop Vectorization.
   2    Copyright (C) 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
   3    Contributed by Dorit Nuzman <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 3, 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 COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "ggc.h"
  26 #include "tree.h"
  27 #include "target.h"
  28 #include "basic-block.h"
  29 #include "diagnostic.h"
  30 #include "tree-flow.h"
  31 #include "tree-dump.h"
  32 #include "cfgloop.h"
  33 #include "expr.h"
  34 #include "optabs.h"
  35 #include "params.h"
  36 #include "tree-data-ref.h"
  37 #include "tree-vectorizer.h"
  38 #include "recog.h"
  39 #include "toplev.h"
  40
  41 /* Function prototypes */
  42 static void vect_pattern_recog_1
  43   (gimple (* ) (gimple, tree *, tree *), gimple_stmt_iterator);
  44 static bool widened_name_p (tree, gimple, tree *, gimple *);
  45
  46 /* Pattern recognition functions  */
  47 static gimple vect_recog_widen_sum_pattern (gimple, tree *, tree *);
  48 static gimple vect_recog_widen_mult_pattern (gimple, tree *, tree *);
  49 static gimple vect_recog_dot_prod_pattern (gimple, tree *, tree *);
  50 static gimple vect_recog_pow_pattern (gimple, tree *, tree *);
  51 static vect_recog_func_ptr vect_vect_recog_func_ptrs[NUM_PATTERNS] = {
  52         vect_recog_widen_mult_pattern,
  53         vect_recog_widen_sum_pattern,
  54         vect_recog_dot_prod_pattern,
  55         vect_recog_pow_pattern};
  56
  57
  58 /* Function widened_name_p
  59
  60    Check whether NAME, an ssa-name used in USE_STMT,
  61    is a result of a type-promotion, such that:
  62      DEF_STMT: NAME = NOP (name0)
  63    where the type of name0 (HALF_TYPE) is smaller than the type of NAME.
  64 */
  65
  66 static bool
  67 widened_name_p (tree name, gimple use_stmt, tree *half_type, gimple *def_stmt)
  68 {
  69   tree dummy;
  70   gimple dummy_gimple;
  71   loop_vec_info loop_vinfo;
  72   stmt_vec_info stmt_vinfo;
  73   tree type = TREE_TYPE (name);
  74   tree oprnd0;
  75   enum vect_def_type dt;
  76   tree def;
  77
  78   stmt_vinfo = vinfo_for_stmt (use_stmt);
  79   loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_vinfo);
  80
  81   if (!vect_is_simple_use (name, loop_vinfo, NULL, def_stmt, &def, &dt))
  82     return false;
  83
  84   if (dt != vect_internal_def
  85       && dt != vect_external_def && dt != vect_constant_def)
  86     return false;
  87
  88   if (! *def_stmt)
  89     return false;
  90
  91   if (!is_gimple_assign (*def_stmt))
  92     return false;
  93
  94   if (gimple_assign_rhs_code (*def_stmt) != NOP_EXPR)
  95     return false;
  96
  97   oprnd0 = gimple_assign_rhs1 (*def_stmt);
  98
  99   *half_type = TREE_TYPE (oprnd0);
 100   if (!INTEGRAL_TYPE_P (type) || !INTEGRAL_TYPE_P (*half_type)
 101       || (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (*half_type))
 102       || (TYPE_PRECISION (type) < (TYPE_PRECISION (*half_type) * 2)))
 103     return false;
 104
 105   if (!vect_is_simple_use (oprnd0, loop_vinfo, NULL, &dummy_gimple, &dummy,
 106                            &dt))
 107     return false;
 108
 109   return true;
 110 }
 111
 112 /* Helper to return a new temporary for pattern of TYPE for STMT.  If STMT
 113    is NULL, the caller must set SSA_NAME_DEF_STMT for the returned SSA var. */
 114
 115 static tree
 116 vect_recog_temp_ssa_var (tree type, gimple stmt)
 117 {
 118   tree var = create_tmp_var (type, "patt");
 119
 120   add_referenced_var (var);
 121   var = make_ssa_name (var, stmt);
 122   return var;
 123 }
 124
 125 /* Function vect_recog_dot_prod_pattern
 126
 127    Try to find the following pattern:
 128
 129      type x_t, y_t;
 130      TYPE1 prod;
 131      TYPE2 sum = init;
 132    loop:
 133      sum_0 = phi <init, sum_1>
 134      S1  x_t = ...
 135      S2  y_t = ...
 136      S3  x_T = (TYPE1) x_t;
 137      S4  y_T = (TYPE1) y_t;
 138      S5  prod = x_T * y_T;
 139      [S6  prod = (TYPE2) prod;  #optional]
 140      S7  sum_1 = prod + sum_0;
 141
 142    where 'TYPE1' is exactly double the size of type 'type', and 'TYPE2' is the
 143    same size of 'TYPE1' or bigger. This is a special case of a reduction
 144    computation.
 145
 146    Input:
 147
 148    * LAST_STMT: A stmt from which the pattern search begins. In the example,
 149    when this function is called with S7, the pattern {S3,S4,S5,S6,S7} will be
 150    detected.
 151
 152    Output:
 153
 154    * TYPE_IN: The type of the input arguments to the pattern.
 155
 156    * TYPE_OUT: The type of the output  of this pattern.
 157
 158    * Return value: A new stmt that will be used to replace the sequence of
 159    stmts that constitute the pattern. In this case it will be:
 160         WIDEN_DOT_PRODUCT <x_t, y_t, sum_0>
 161
 162    Note: The dot-prod idiom is a widening reduction pattern that is
 163          vectorized without preserving all the intermediate results. It
 164          produces only N/2 (widened) results (by summing up pairs of
 165          intermediate results) rather than all N results.  Therefore, we
 166          cannot allow this pattern when we want to get all the results and in
 167          the correct order (as is the case when this computation is in an
 168          inner-loop nested in an outer-loop that us being vectorized).  */
 169
 170 static gimple
 171 vect_recog_dot_prod_pattern (gimple last_stmt, tree *type_in, tree *type_out)
 172 {
 173   gimple stmt;
 174   tree oprnd0, oprnd1;
 175   tree oprnd00, oprnd01;
 176   stmt_vec_info stmt_vinfo = vinfo_for_stmt (last_stmt);
 177   tree type, half_type;
 178   gimple pattern_stmt;
 179   tree prod_type;
 180   loop_vec_info loop_info = STMT_VINFO_LOOP_VINFO (stmt_vinfo);
 181   struct loop *loop = LOOP_VINFO_LOOP (loop_info);
 182   tree var, rhs;
 183
 184   if (!is_gimple_assign (last_stmt))
 185     return NULL;
 186
 187   type = gimple_expr_type (last_stmt);
 188
 189   /* Look for the following pattern
 190           DX = (TYPE1) X;
 191           DY = (TYPE1) Y;
 192           DPROD = DX * DY;
 193           DDPROD = (TYPE2) DPROD;
 194           sum_1 = DDPROD + sum_0;
 195      In which
 196      - DX is double the size of X
 197      - DY is double the size of Y
 198      - DX, DY, DPROD all have the same type
 199      - sum is the same size of DPROD or bigger
 200      - sum has been recognized as a reduction variable.
 201
 202      This is equivalent to:
 203        DPROD = X w* Y;          #widen mult
 204        sum_1 = DPROD w+ sum_0;  #widen summation
 205      or
 206        DPROD = X w* Y;          #widen mult
 207        sum_1 = DPROD + sum_0;   #summation
 208    */
 209
 210   /* Starting from LAST_STMT, follow the defs of its uses in search
 211      of the above pattern.  */
 212
 213   if (gimple_assign_rhs_code (last_stmt) != PLUS_EXPR)
 214     return NULL;
 215
 216   if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo))
 217     {
 218       /* Has been detected as widening-summation?  */
 219
 220       stmt = STMT_VINFO_RELATED_STMT (stmt_vinfo);
 221       type = gimple_expr_type (stmt);
 222       if (gimple_assign_rhs_code (stmt) != WIDEN_SUM_EXPR)
 223         return NULL;
 224       oprnd0 = gimple_assign_rhs1 (stmt);
 225       oprnd1 = gimple_assign_rhs2 (stmt);
 226       half_type = TREE_TYPE (oprnd0);
 227     }
 228   else
 229     {
 230       gimple def_stmt;
 231
 232       if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def)
 233         return NULL;
 234       oprnd0 = gimple_assign_rhs1 (last_stmt);
 235       oprnd1 = gimple_assign_rhs2 (last_stmt);
 236       if (!types_compatible_p (TREE_TYPE (oprnd0), type)
 237           || !types_compatible_p (TREE_TYPE (oprnd1), type))
 238         return NULL;
 239       stmt = last_stmt;
 240
 241       if (widened_name_p (oprnd0, stmt, &half_type, &def_stmt))
 242         {
 243           stmt = def_stmt;
 244           oprnd0 = gimple_assign_rhs1 (stmt);
 245         }
 246       else
 247         half_type = type;
 248     }
 249
 250   /* So far so good. Since last_stmt was detected as a (summation) reduction,
 251      we know that oprnd1 is the reduction variable (defined by a loop-header
 252      phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
 253      Left to check that oprnd0 is defined by a (widen_)mult_expr  */
 254
 255   prod_type = half_type;
 256   stmt = SSA_NAME_DEF_STMT (oprnd0);
 257   /* FORNOW.  Can continue analyzing the def-use chain when this stmt in a phi
 258      inside the loop (in case we are analyzing an outer-loop).  */
 259   if (!is_gimple_assign (stmt))
 260     return NULL;
 261   stmt_vinfo = vinfo_for_stmt (stmt);
 262   gcc_assert (stmt_vinfo);
 263   if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_internal_def)
 264     return NULL;
 265   if (gimple_assign_rhs_code (stmt) != MULT_EXPR)
 266     return NULL;
 267   if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo))
 268     {
 269       /* Has been detected as a widening multiplication?  */
 270
 271       stmt = STMT_VINFO_RELATED_STMT (stmt_vinfo);
 272       if (gimple_assign_rhs_code (stmt) != WIDEN_MULT_EXPR)
 273         return NULL;
 274       stmt_vinfo = vinfo_for_stmt (stmt);
 275       gcc_assert (stmt_vinfo);
 276       gcc_assert (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_internal_def);
 277       oprnd00 = gimple_assign_rhs1 (stmt);
 278       oprnd01 = gimple_assign_rhs2 (stmt);
 279     }
 280   else
 281     {
 282       tree half_type0, half_type1;
 283       gimple def_stmt;
 284       tree oprnd0, oprnd1;
 285
 286       oprnd0 = gimple_assign_rhs1 (stmt);
 287       oprnd1 = gimple_assign_rhs2 (stmt);
 288       if (!types_compatible_p (TREE_TYPE (oprnd0), prod_type)
 289           || !types_compatible_p (TREE_TYPE (oprnd1), prod_type))
 290         return NULL;
 291       if (!widened_name_p (oprnd0, stmt, &half_type0, &def_stmt))
 292         return NULL;
 293       oprnd00 = gimple_assign_rhs1 (def_stmt);
 294       if (!widened_name_p (oprnd1, stmt, &half_type1, &def_stmt))
 295         return NULL;
 296       oprnd01 = gimple_assign_rhs1 (def_stmt);
 297       if (!types_compatible_p (half_type0, half_type1))
 298         return NULL;
 299       if (TYPE_PRECISION (prod_type) != TYPE_PRECISION (half_type0) * 2)
 300         return NULL;
 301     }
 302
 303   half_type = TREE_TYPE (oprnd00);
 304   *type_in = half_type;
 305   *type_out = type;
 306
 307   /* Pattern detected. Create a stmt to be used to replace the pattern: */
 308   var = vect_recog_temp_ssa_var (type, NULL);
 309   rhs = build3 (DOT_PROD_EXPR, type, oprnd00, oprnd01, oprnd1),
 310   pattern_stmt = gimple_build_assign (var, rhs);
 311
 312   if (vect_print_dump_info (REPORT_DETAILS))
 313     {
 314       fprintf (vect_dump, "vect_recog_dot_prod_pattern: detected: ");
 315       print_gimple_stmt (vect_dump, pattern_stmt, 0, TDF_SLIM);
 316     }
 317
 318   /* We don't allow changing the order of the computation in the inner-loop
 319      when doing outer-loop vectorization.  */
 320   gcc_assert (!nested_in_vect_loop_p (loop, last_stmt));
 321
 322   return pattern_stmt;
 323 }
 324
 325 /* Function vect_recog_widen_mult_pattern
 326
 327    Try to find the following pattern:
 328
 329      type a_t, b_t;
 330      TYPE a_T, b_T, prod_T;
 331
 332      S1  a_t = ;
 333      S2  b_t = ;
 334      S3  a_T = (TYPE) a_t;
 335      S4  b_T = (TYPE) b_t;
 336      S5  prod_T = a_T * b_T;
 337
 338    where type 'TYPE' is at least double the size of type 'type'.
 339
 340    Input:
 341
 342    * LAST_STMT: A stmt from which the pattern search begins. In the example,
 343    when this function is called with S5, the pattern {S3,S4,S5} is be detected.
 344
 345    Output:
 346
 347    * TYPE_IN: The type of the input arguments to the pattern.
 348
 349    * TYPE_OUT: The type of the output  of this pattern.
 350
 351    * Return value: A new stmt that will be used to replace the sequence of
 352    stmts that constitute the pattern. In this case it will be:
 353         WIDEN_MULT <a_t, b_t>
 354 */
 355
 356 static gimple
 357 vect_recog_widen_mult_pattern (gimple last_stmt,
 358                                tree *type_in,
 359                                tree *type_out)
 360 {
 361   gimple def_stmt0, def_stmt1;
 362   tree oprnd0, oprnd1;
 363   tree type, half_type0, half_type1;
 364   gimple pattern_stmt;
 365   tree vectype;
 366   tree dummy;
 367   tree var;
 368   enum tree_code dummy_code;
 369   int dummy_int;
 370   VEC (tree, heap) *dummy_vec;
 371
 372   if (!is_gimple_assign (last_stmt))
 373     return NULL;
 374
 375   type = gimple_expr_type (last_stmt);
 376
 377   /* Starting from LAST_STMT, follow the defs of its uses in search
 378      of the above pattern.  */
 379
 380   if (gimple_assign_rhs_code (last_stmt) != MULT_EXPR)
 381     return NULL;
 382
 383   oprnd0 = gimple_assign_rhs1 (last_stmt);
 384   oprnd1 = gimple_assign_rhs2 (last_stmt);
 385   if (!types_compatible_p (TREE_TYPE (oprnd0), type)
 386       || !types_compatible_p (TREE_TYPE (oprnd1), type))
 387     return NULL;
 388
 389   /* Check argument 0 */
 390   if (!widened_name_p (oprnd0, last_stmt, &half_type0, &def_stmt0))
 391     return NULL;
 392   oprnd0 = gimple_assign_rhs1 (def_stmt0);
 393
 394   /* Check argument 1 */
 395   if (!widened_name_p (oprnd1, last_stmt, &half_type1, &def_stmt1))
 396     return NULL;
 397   oprnd1 = gimple_assign_rhs1 (def_stmt1);
 398
 399   if (!types_compatible_p (half_type0, half_type1))
 400     return NULL;
 401
 402   /* Pattern detected.  */
 403   if (vect_print_dump_info (REPORT_DETAILS))
 404     fprintf (vect_dump, "vect_recog_widen_mult_pattern: detected: ");
 405
 406   /* Check target support  */
 407   vectype = get_vectype_for_scalar_type (half_type0);
 408   if (!vectype
 409       || !supportable_widening_operation (WIDEN_MULT_EXPR, last_stmt, vectype,
 410                                           &dummy, &dummy, &dummy_code,
 411                                           &dummy_code, &dummy_int, &dummy_vec))
 412     return NULL;
 413
 414   *type_in = vectype;
 415   *type_out = NULL_TREE;
 416
 417   /* Pattern supported. Create a stmt to be used to replace the pattern: */
 418   var = vect_recog_temp_ssa_var (type, NULL);
 419   pattern_stmt = gimple_build_assign_with_ops (WIDEN_MULT_EXPR, var, oprnd0,
 420                                                oprnd1);
 421   SSA_NAME_DEF_STMT (var) = pattern_stmt;
 422
 423   if (vect_print_dump_info (REPORT_DETAILS))
 424     print_gimple_stmt (vect_dump, pattern_stmt, 0, TDF_SLIM);
 425
 426   return pattern_stmt;
 427 }
 428
 429
 430 /* Function vect_recog_pow_pattern
 431
 432    Try to find the following pattern:
 433
 434      x = POW (y, N);
 435
 436    with POW being one of pow, powf, powi, powif and N being
 437    either 2 or 0.5.
 438
 439    Input:
 440
 441    * LAST_STMT: A stmt from which the pattern search begins.
 442
 443    Output:
 444
 445    * TYPE_IN: The type of the input arguments to the pattern.
 446
 447    * TYPE_OUT: The type of the output of this pattern.
 448
 449    * Return value: A new stmt that will be used to replace the sequence of
 450    stmts that constitute the pattern. In this case it will be:
 451         x = x * x
 452    or
 453         x = sqrt (x)
 454 */
 455
 456 static gimple
 457 vect_recog_pow_pattern (gimple last_stmt, tree *type_in, tree *type_out)
 458 {
 459   tree type;
 460   tree fn, base, exp = NULL;
 461   gimple stmt;
 462   tree var;
 463
 464   if (!is_gimple_call (last_stmt) || gimple_call_lhs (last_stmt) == NULL)
 465     return NULL;
 466
 467   type = gimple_expr_type (last_stmt);
 468
 469   fn = gimple_call_fndecl (last_stmt);
 470   switch (DECL_FUNCTION_CODE (fn))
 471     {
 472     case BUILT_IN_POWIF:
 473     case BUILT_IN_POWI:
 474     case BUILT_IN_POWF:
 475     case BUILT_IN_POW:
 476       base = gimple_call_arg (last_stmt, 0);
 477       exp = gimple_call_arg (last_stmt, 1);
 478       if (TREE_CODE (exp) != REAL_CST
 479           && TREE_CODE (exp) != INTEGER_CST)
 480         return NULL;
 481       break;
 482
 483     default:
 484       return NULL;
 485     }
 486
 487   /* We now have a pow or powi builtin function call with a constant
 488      exponent.  */
 489
 490   *type_out = NULL_TREE;
 491
 492   /* Catch squaring.  */
 493   if ((host_integerp (exp, 0)
 494        && tree_low_cst (exp, 0) == 2)
 495       || (TREE_CODE (exp) == REAL_CST
 496           && REAL_VALUES_EQUAL (TREE_REAL_CST (exp), dconst2)))
 497     {
 498       *type_in = TREE_TYPE (base);
 499
 500       var = vect_recog_temp_ssa_var (TREE_TYPE (base), NULL);
 501       stmt = gimple_build_assign_with_ops (MULT_EXPR, var, base, base);
 502       SSA_NAME_DEF_STMT (var) = stmt;
 503       return stmt;
 504     }
 505
 506   /* Catch square root.  */
 507   if (TREE_CODE (exp) == REAL_CST
 508       && REAL_VALUES_EQUAL (TREE_REAL_CST (exp), dconsthalf))
 509     {
 510       tree newfn = mathfn_built_in (TREE_TYPE (base), BUILT_IN_SQRT);
 511       *type_in = get_vectype_for_scalar_type (TREE_TYPE (base));
 512       if (*type_in)
 513         {
 514           gimple stmt = gimple_build_call (newfn, 1, base);
 515           if (vectorizable_function (stmt, *type_in, *type_in)
 516               != NULL_TREE)
 517             {
 518               var = vect_recog_temp_ssa_var (TREE_TYPE (base), stmt);
 519               gimple_call_set_lhs (stmt, var);
 520               return stmt;
 521             }
 522         }
 523     }
 524
 525   return NULL;
 526 }
 527
 528
 529 /* Function vect_recog_widen_sum_pattern
 530
 531    Try to find the following pattern:
 532
 533      type x_t;
 534      TYPE x_T, sum = init;
 535    loop:
 536      sum_0 = phi <init, sum_1>
 537      S1  x_t = *p;
 538      S2  x_T = (TYPE) x_t;
 539      S3  sum_1 = x_T + sum_0;
 540
 541    where type 'TYPE' is at least double the size of type 'type', i.e - we're
 542    summing elements of type 'type' into an accumulator of type 'TYPE'. This is
 543    a special case of a reduction computation.
 544
 545    Input:
 546
 547    * LAST_STMT: A stmt from which the pattern search begins. In the example,
 548    when this function is called with S3, the pattern {S2,S3} will be detected.
 549
 550    Output:
 551
 552    * TYPE_IN: The type of the input arguments to the pattern.
 553
 554    * TYPE_OUT: The type of the output of this pattern.
 555
 556    * Return value: A new stmt that will be used to replace the sequence of
 557    stmts that constitute the pattern. In this case it will be:
 558         WIDEN_SUM <x_t, sum_0>
 559
 560    Note: The widening-sum idiom is a widening reduction pattern that is
 561          vectorized without preserving all the intermediate results. It
 562          produces only N/2 (widened) results (by summing up pairs of
 563          intermediate results) rather than all N results.  Therefore, we
 564          cannot allow this pattern when we want to get all the results and in
 565          the correct order (as is the case when this computation is in an
 566          inner-loop nested in an outer-loop that us being vectorized).  */
 567
 568 static gimple
 569 vect_recog_widen_sum_pattern (gimple last_stmt, tree *type_in, tree *type_out)
 570 {
 571   gimple stmt;
 572   tree oprnd0, oprnd1;
 573   stmt_vec_info stmt_vinfo = vinfo_for_stmt (last_stmt);
 574   tree type, half_type;
 575   gimple pattern_stmt;
 576   loop_vec_info loop_info = STMT_VINFO_LOOP_VINFO (stmt_vinfo);
 577   struct loop *loop = LOOP_VINFO_LOOP (loop_info);
 578   tree var;
 579
 580   if (!is_gimple_assign (last_stmt))
 581     return NULL;
 582
 583   type = gimple_expr_type (last_stmt);
 584
 585   /* Look for the following pattern
 586           DX = (TYPE) X;
 587           sum_1 = DX + sum_0;
 588      In which DX is at least double the size of X, and sum_1 has been
 589      recognized as a reduction variable.
 590    */
 591
 592   /* Starting from LAST_STMT, follow the defs of its uses in search
 593      of the above pattern.  */
 594
 595   if (gimple_assign_rhs_code (last_stmt) != PLUS_EXPR)
 596     return NULL;
 597
 598   if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def)
 599     return NULL;
 600
 601   oprnd0 = gimple_assign_rhs1 (last_stmt);
 602   oprnd1 = gimple_assign_rhs2 (last_stmt);
 603   if (!types_compatible_p (TREE_TYPE (oprnd0), type)
 604       || !types_compatible_p (TREE_TYPE (oprnd1), type))
 605     return NULL;
 606
 607   /* So far so good. Since last_stmt was detected as a (summation) reduction,
 608      we know that oprnd1 is the reduction variable (defined by a loop-header
 609      phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
 610      Left to check that oprnd0 is defined by a cast from type 'type' to type
 611      'TYPE'.  */
 612
 613   if (!widened_name_p (oprnd0, last_stmt, &half_type, &stmt))
 614     return NULL;
 615
 616   oprnd0 = gimple_assign_rhs1 (stmt);
 617   *type_in = half_type;
 618   *type_out = type;
 619
 620   /* Pattern detected. Create a stmt to be used to replace the pattern: */
 621   var = vect_recog_temp_ssa_var (type, NULL);
 622   pattern_stmt = gimple_build_assign_with_ops (WIDEN_SUM_EXPR, var,
 623                                                oprnd0, oprnd1);
 624   SSA_NAME_DEF_STMT (var) = pattern_stmt;
 625
 626   if (vect_print_dump_info (REPORT_DETAILS))
 627     {
 628       fprintf (vect_dump, "vect_recog_widen_sum_pattern: detected: ");
 629       print_gimple_stmt (vect_dump, pattern_stmt, 0, TDF_SLIM);
 630     }
 631
 632   /* We don't allow changing the order of the computation in the inner-loop
 633      when doing outer-loop vectorization.  */
 634   gcc_assert (!nested_in_vect_loop_p (loop, last_stmt));
 635
 636   return pattern_stmt;
 637 }
 638
 639
 640 /* Function vect_pattern_recog_1
 641
 642    Input:
 643    PATTERN_RECOG_FUNC: A pointer to a function that detects a certain
 644         computation pattern.
 645    STMT: A stmt from which the pattern search should start.
 646
 647    If PATTERN_RECOG_FUNC successfully detected the pattern, it creates an
 648    expression that computes the same functionality and can be used to
 649    replace the sequence of stmts that are involved in the pattern.
 650
 651    Output:
 652    This function checks if the expression returned by PATTERN_RECOG_FUNC is
 653    supported in vector form by the target.  We use 'TYPE_IN' to obtain the
 654    relevant vector type. If 'TYPE_IN' is already a vector type, then this
 655    indicates that target support had already been checked by PATTERN_RECOG_FUNC.
 656    If 'TYPE_OUT' is also returned by PATTERN_RECOG_FUNC, we check that it fits
 657    to the available target pattern.
 658
 659    This function also does some bookkeeping, as explained in the documentation
 660    for vect_recog_pattern.  */
 661
 662 static void
 663 vect_pattern_recog_1 (
 664         gimple (* vect_recog_func) (gimple, tree *, tree *),
 665         gimple_stmt_iterator si)
 666 {
 667   gimple stmt = gsi_stmt (si), pattern_stmt;
 668   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
 669   stmt_vec_info pattern_stmt_info;
 670   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
 671   tree pattern_vectype;
 672   tree type_in, type_out;
 673   enum tree_code code;
 674
 675   pattern_stmt = (* vect_recog_func) (stmt, &type_in, &type_out);
 676   if (!pattern_stmt)
 677     return;
 678
 679   if (VECTOR_MODE_P (TYPE_MODE (type_in)))
 680     {
 681       /* No need to check target support (already checked by the pattern
 682          recognition function).  */
 683       pattern_vectype = type_in;
 684     }
 685   else
 686     {
 687       enum machine_mode vec_mode;
 688       enum insn_code icode;
 689       optab optab;
 690
 691       /* Check target support  */
 692       pattern_vectype = get_vectype_for_scalar_type (type_in);
 693       if (!pattern_vectype)
 694         return;
 695
 696       if (is_gimple_assign (pattern_stmt))
 697         code = gimple_assign_rhs_code (pattern_stmt);
 698       else
 699         {
 700           gcc_assert (is_gimple_call (pattern_stmt));
 701           code = CALL_EXPR;
 702         }
 703
 704       optab = optab_for_tree_code (code, pattern_vectype, optab_default);
 705       vec_mode = TYPE_MODE (pattern_vectype);
 706       if (!optab
 707           || (icode = optab_handler (optab, vec_mode)->insn_code) ==
 708               CODE_FOR_nothing
 709           || (type_out
 710               && (!get_vectype_for_scalar_type (type_out)
 711                   || (insn_data[icode].operand[0].mode !=
 712                       TYPE_MODE (get_vectype_for_scalar_type (type_out))))))
 713         return;
 714     }
 715
 716   /* Found a vectorizable pattern.  */
 717   if (vect_print_dump_info (REPORT_DETAILS))
 718     {
 719       fprintf (vect_dump, "pattern recognized: ");
 720       print_gimple_stmt (vect_dump, pattern_stmt, 0, TDF_SLIM);
 721     }
 722
 723   /* Mark the stmts that are involved in the pattern. */
 724   gsi_insert_before (&si, pattern_stmt, GSI_SAME_STMT);
 725   set_vinfo_for_stmt (pattern_stmt,
 726                       new_stmt_vec_info (pattern_stmt, loop_vinfo, NULL));
 727   pattern_stmt_info = vinfo_for_stmt (pattern_stmt);
 728
 729   STMT_VINFO_RELATED_STMT (pattern_stmt_info) = stmt;
 730   STMT_VINFO_DEF_TYPE (pattern_stmt_info) = STMT_VINFO_DEF_TYPE (stmt_info);
 731   STMT_VINFO_VECTYPE (pattern_stmt_info) = pattern_vectype;
 732   STMT_VINFO_IN_PATTERN_P (stmt_info) = true;
 733   STMT_VINFO_RELATED_STMT (stmt_info) = pattern_stmt;
 734
 735   return;
 736 }
 737
 738
 739 /* Function vect_pattern_recog
 740
 741    Input:
 742    LOOP_VINFO - a struct_loop_info of a loop in which we want to look for
 743         computation idioms.
 744
 745    Output - for each computation idiom that is detected we insert a new stmt
 746         that provides the same functionality and that can be vectorized. We
 747         also record some information in the struct_stmt_info of the relevant
 748         stmts, as explained below:
 749
 750    At the entry to this function we have the following stmts, with the
 751    following initial value in the STMT_VINFO fields:
 752
 753          stmt                     in_pattern_p  related_stmt    vec_stmt
 754          S1: a_i = ....                 -       -               -
 755          S2: a_2 = ..use(a_i)..         -       -               -
 756          S3: a_1 = ..use(a_2)..         -       -               -
 757          S4: a_0 = ..use(a_1)..         -       -               -
 758          S5: ... = ..use(a_0)..         -       -               -
 759
 760    Say the sequence {S1,S2,S3,S4} was detected as a pattern that can be
 761    represented by a single stmt. We then:
 762    - create a new stmt S6 that will replace the pattern.
 763    - insert the new stmt S6 before the last stmt in the pattern
 764    - fill in the STMT_VINFO fields as follows:
 765
 766                                   in_pattern_p  related_stmt    vec_stmt
 767          S1: a_i = ....                 -       -               -
 768          S2: a_2 = ..use(a_i)..         -       -               -
 769          S3: a_1 = ..use(a_2)..         -       -               -
 770        > S6: a_new = ....               -       S4              -
 771          S4: a_0 = ..use(a_1)..         true    S6              -
 772          S5: ... = ..use(a_0)..         -       -               -
 773
 774    (the last stmt in the pattern (S4) and the new pattern stmt (S6) point
 775     to each other through the RELATED_STMT field).
 776
 777    S6 will be marked as relevant in vect_mark_stmts_to_be_vectorized instead
 778    of S4 because it will replace all its uses.  Stmts {S1,S2,S3} will
 779    remain irrelevant unless used by stmts other than S4.
 780
 781    If vectorization succeeds, vect_transform_stmt will skip over {S1,S2,S3}
 782    (because they are marked as irrelevant). It will vectorize S6, and record
 783    a pointer to the new vector stmt VS6 both from S6 (as usual), and also
 784    from S4. We do that so that when we get to vectorizing stmts that use the
 785    def of S4 (like S5 that uses a_0), we'll know where to take the relevant
 786    vector-def from. S4 will be skipped, and S5 will be vectorized as usual:
 787
 788                                   in_pattern_p  related_stmt    vec_stmt
 789          S1: a_i = ....                 -       -               -
 790          S2: a_2 = ..use(a_i)..         -       -               -
 791          S3: a_1 = ..use(a_2)..         -       -               -
 792        > VS6: va_new = ....             -       -               -
 793          S6: a_new = ....               -       S4              VS6
 794          S4: a_0 = ..use(a_1)..         true    S6              VS6
 795        > VS5: ... = ..vuse(va_new)..    -       -               -
 796          S5: ... = ..use(a_0)..         -       -               -
 797
 798    DCE could then get rid of {S1,S2,S3,S4,S5,S6} (if their defs are not used
 799    elsewhere), and we'll end up with:
 800
 801         VS6: va_new = ....
 802         VS5: ... = ..vuse(va_new)..
 803
 804    If vectorization does not succeed, DCE will clean S6 away (its def is
 805    not used), and we'll end up with the original sequence.
 806 */
 807
 808 void
 809 vect_pattern_recog (loop_vec_info loop_vinfo)
 810 {
 811   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
 812   basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
 813   unsigned int nbbs = loop->num_nodes;
 814   gimple_stmt_iterator si;
 815   gimple stmt;
 816   unsigned int i, j;
 817   gimple (* vect_recog_func_ptr) (gimple, tree *, tree *);
 818
 819   if (vect_print_dump_info (REPORT_DETAILS))
 820     fprintf (vect_dump, "=== vect_pattern_recog ===");
 821
 822   /* Scan through the loop stmts, applying the pattern recognition
 823      functions starting at each stmt visited:  */
 824   for (i = 0; i < nbbs; i++)
 825     {
 826       basic_block bb = bbs[i];
 827       for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
 828         {
 829           stmt = gsi_stmt (si);
 830
 831           /* Scan over all generic vect_recog_xxx_pattern functions.  */
 832           for (j = 0; j < NUM_PATTERNS; j++)
 833             {
 834               vect_recog_func_ptr = vect_vect_recog_func_ptrs[j];
 835               vect_pattern_recog_1 (vect_recog_func_ptr, si);
 836             }
 837         }
 838     }
 839 }