gcc/tree-vect-patterns.c

   1 /* Analysis Utilities for Loop Vectorization.
   2    Copyright (C) 2006, 2007, 2008, 2009, 2010 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 "gimple-pretty-print.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, vectype_out;
 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   vectype_out = get_vectype_for_scalar_type (type);
 409   if (!vectype
 410       || !supportable_widening_operation (WIDEN_MULT_EXPR, last_stmt,
 411                                           vectype_out, vectype,
 412                                           &dummy, &dummy, &dummy_code,
 413                                           &dummy_code, &dummy_int, &dummy_vec))
 414     return NULL;
 415
 416   *type_in = vectype;
 417   *type_out = vectype_out;
 418
 419   /* Pattern supported. Create a stmt to be used to replace the pattern: */
 420   var = vect_recog_temp_ssa_var (type, NULL);
 421   pattern_stmt = gimple_build_assign_with_ops (WIDEN_MULT_EXPR, var, oprnd0,
 422                                                oprnd1);
 423   SSA_NAME_DEF_STMT (var) = pattern_stmt;
 424
 425   if (vect_print_dump_info (REPORT_DETAILS))
 426     print_gimple_stmt (vect_dump, pattern_stmt, 0, TDF_SLIM);
 427
 428   return pattern_stmt;
 429 }
 430
 431
 432 /* Function vect_recog_pow_pattern
 433
 434    Try to find the following pattern:
 435
 436      x = POW (y, N);
 437
 438    with POW being one of pow, powf, powi, powif and N being
 439    either 2 or 0.5.
 440
 441    Input:
 442
 443    * LAST_STMT: A stmt from which the pattern search begins.
 444
 445    Output:
 446
 447    * TYPE_IN: The type of the input arguments to the pattern.
 448
 449    * TYPE_OUT: The type of the output of this pattern.
 450
 451    * Return value: A new stmt that will be used to replace the sequence of
 452    stmts that constitute the pattern. In this case it will be:
 453         x = x * x
 454    or
 455         x = sqrt (x)
 456 */
 457
 458 static gimple
 459 vect_recog_pow_pattern (gimple last_stmt, tree *type_in, tree *type_out)
 460 {
 461   tree fn, base, exp = NULL;
 462   gimple stmt;
 463   tree var;
 464
 465   if (!is_gimple_call (last_stmt) || gimple_call_lhs (last_stmt) == NULL)
 466     return NULL;
 467
 468   fn = gimple_call_fndecl (last_stmt);
 469   switch (DECL_FUNCTION_CODE (fn))
 470     {
 471     case BUILT_IN_POWIF:
 472     case BUILT_IN_POWI:
 473     case BUILT_IN_POWF:
 474     case BUILT_IN_POW:
 475       base = gimple_call_arg (last_stmt, 0);
 476       exp = gimple_call_arg (last_stmt, 1);
 477       if (TREE_CODE (exp) != REAL_CST
 478           && TREE_CODE (exp) != INTEGER_CST)
 479         return NULL;
 480       break;
 481
 482     default:
 483       return NULL;
 484     }
 485
 486   /* We now have a pow or powi builtin function call with a constant
 487      exponent.  */
 488
 489   *type_out = NULL_TREE;
 490
 491   /* Catch squaring.  */
 492   if ((host_integerp (exp, 0)
 493        && tree_low_cst (exp, 0) == 2)
 494       || (TREE_CODE (exp) == REAL_CST
 495           && REAL_VALUES_EQUAL (TREE_REAL_CST (exp), dconst2)))
 496     {
 497       *type_in = TREE_TYPE (base);
 498
 499       var = vect_recog_temp_ssa_var (TREE_TYPE (base), NULL);
 500       stmt = gimple_build_assign_with_ops (MULT_EXPR, var, base, base);
 501       SSA_NAME_DEF_STMT (var) = stmt;
 502       return stmt;
 503     }
 504
 505   /* Catch square root.  */
 506   if (TREE_CODE (exp) == REAL_CST
 507       && REAL_VALUES_EQUAL (TREE_REAL_CST (exp), dconsthalf))
 508     {
 509       tree newfn = mathfn_built_in (TREE_TYPE (base), BUILT_IN_SQRT);
 510       *type_in = get_vectype_for_scalar_type (TREE_TYPE (base));
 511       if (*type_in)
 512         {
 513           gimple stmt = gimple_build_call (newfn, 1, base);
 514           if (vectorizable_function (stmt, *type_in, *type_in)
 515               != NULL_TREE)
 516             {
 517               var = vect_recog_temp_ssa_var (TREE_TYPE (base), stmt);
 518               gimple_call_set_lhs (stmt, var);
 519               return stmt;
 520             }
 521         }
 522     }
 523
 524   return NULL;
 525 }
 526
 527
 528 /* Function vect_recog_widen_sum_pattern
 529
 530    Try to find the following pattern:
 531
 532      type x_t;
 533      TYPE x_T, sum = init;
 534    loop:
 535      sum_0 = phi <init, sum_1>
 536      S1  x_t = *p;
 537      S2  x_T = (TYPE) x_t;
 538      S3  sum_1 = x_T + sum_0;
 539
 540    where type 'TYPE' is at least double the size of type 'type', i.e - we're
 541    summing elements of type 'type' into an accumulator of type 'TYPE'. This is
 542    a special case of a reduction computation.
 543
 544    Input:
 545
 546    * LAST_STMT: A stmt from which the pattern search begins. In the example,
 547    when this function is called with S3, the pattern {S2,S3} will be detected.
 548
 549    Output:
 550
 551    * TYPE_IN: The type of the input arguments to the pattern.
 552
 553    * TYPE_OUT: The type of the output of this pattern.
 554
 555    * Return value: A new stmt that will be used to replace the sequence of
 556    stmts that constitute the pattern. In this case it will be:
 557         WIDEN_SUM <x_t, sum_0>
 558
 559    Note: The widening-sum idiom is a widening reduction pattern that is
 560          vectorized without preserving all the intermediate results. It
 561          produces only N/2 (widened) results (by summing up pairs of
 562          intermediate results) rather than all N results.  Therefore, we
 563          cannot allow this pattern when we want to get all the results and in
 564          the correct order (as is the case when this computation is in an
 565          inner-loop nested in an outer-loop that us being vectorized).  */
 566
 567 static gimple
 568 vect_recog_widen_sum_pattern (gimple last_stmt, tree *type_in, tree *type_out)
 569 {
 570   gimple stmt;
 571   tree oprnd0, oprnd1;
 572   stmt_vec_info stmt_vinfo = vinfo_for_stmt (last_stmt);
 573   tree type, half_type;
 574   gimple pattern_stmt;
 575   loop_vec_info loop_info = STMT_VINFO_LOOP_VINFO (stmt_vinfo);
 576   struct loop *loop = LOOP_VINFO_LOOP (loop_info);
 577   tree var;
 578
 579   if (!is_gimple_assign (last_stmt))
 580     return NULL;
 581
 582   type = gimple_expr_type (last_stmt);
 583
 584   /* Look for the following pattern
 585           DX = (TYPE) X;
 586           sum_1 = DX + sum_0;
 587      In which DX is at least double the size of X, and sum_1 has been
 588      recognized as a reduction variable.
 589    */
 590
 591   /* Starting from LAST_STMT, follow the defs of its uses in search
 592      of the above pattern.  */
 593
 594   if (gimple_assign_rhs_code (last_stmt) != PLUS_EXPR)
 595     return NULL;
 596
 597   if (STMT_VINFO_DEF_TYPE (stmt_vinfo) != vect_reduction_def)
 598     return NULL;
 599
 600   oprnd0 = gimple_assign_rhs1 (last_stmt);
 601   oprnd1 = gimple_assign_rhs2 (last_stmt);
 602   if (!types_compatible_p (TREE_TYPE (oprnd0), type)
 603       || !types_compatible_p (TREE_TYPE (oprnd1), type))
 604     return NULL;
 605
 606   /* So far so good. Since last_stmt was detected as a (summation) reduction,
 607      we know that oprnd1 is the reduction variable (defined by a loop-header
 608      phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
 609      Left to check that oprnd0 is defined by a cast from type 'type' to type
 610      'TYPE'.  */
 611
 612   if (!widened_name_p (oprnd0, last_stmt, &half_type, &stmt))
 613     return NULL;
 614
 615   oprnd0 = gimple_assign_rhs1 (stmt);
 616   *type_in = half_type;
 617   *type_out = type;
 618
 619   /* Pattern detected. Create a stmt to be used to replace the pattern: */
 620   var = vect_recog_temp_ssa_var (type, NULL);
 621   pattern_stmt = gimple_build_assign_with_ops (WIDEN_SUM_EXPR, var,
 622                                                oprnd0, oprnd1);
 623   SSA_NAME_DEF_STMT (var) = pattern_stmt;
 624
 625   if (vect_print_dump_info (REPORT_DETAILS))
 626     {
 627       fprintf (vect_dump, "vect_recog_widen_sum_pattern: detected: ");
 628       print_gimple_stmt (vect_dump, pattern_stmt, 0, TDF_SLIM);
 629     }
 630
 631   /* We don't allow changing the order of the computation in the inner-loop
 632      when doing outer-loop vectorization.  */
 633   gcc_assert (!nested_in_vect_loop_p (loop, last_stmt));
 634
 635   return pattern_stmt;
 636 }
 637
 638
 639 /* Function vect_pattern_recog_1
 640
 641    Input:
 642    PATTERN_RECOG_FUNC: A pointer to a function that detects a certain
 643         computation pattern.
 644    STMT: A stmt from which the pattern search should start.
 645
 646    If PATTERN_RECOG_FUNC successfully detected the pattern, it creates an
 647    expression that computes the same functionality and can be used to
 648    replace the sequence of stmts that are involved in the pattern.
 649
 650    Output:
 651    This function checks if the expression returned by PATTERN_RECOG_FUNC is
 652    supported in vector form by the target.  We use 'TYPE_IN' to obtain the
 653    relevant vector type. If 'TYPE_IN' is already a vector type, then this
 654    indicates that target support had already been checked by PATTERN_RECOG_FUNC.
 655    If 'TYPE_OUT' is also returned by PATTERN_RECOG_FUNC, we check that it fits
 656    to the available target pattern.
 657
 658    This function also does some bookkeeping, as explained in the documentation
 659    for vect_recog_pattern.  */
 660
 661 static void
 662 vect_pattern_recog_1 (
 663         gimple (* vect_recog_func) (gimple, tree *, tree *),
 664         gimple_stmt_iterator si)
 665 {
 666   gimple stmt = gsi_stmt (si), pattern_stmt;
 667   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
 668   stmt_vec_info pattern_stmt_info;
 669   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
 670   tree pattern_vectype;
 671   tree type_in, type_out;
 672   enum tree_code code;
 673   int i;
 674   gimple next;
 675
 676   pattern_stmt = (* vect_recog_func) (stmt, &type_in, &type_out);
 677   if (!pattern_stmt)
 678     return;
 679
 680   if (VECTOR_MODE_P (TYPE_MODE (type_in)))
 681     {
 682       /* No need to check target support (already checked by the pattern
 683          recognition function).  */
 684       if (type_out)
 685         gcc_assert (VECTOR_MODE_P (TYPE_MODE (type_out)));
 686       pattern_vectype = type_out ? type_out : type_in;
 687     }
 688   else
 689     {
 690       enum machine_mode vec_mode;
 691       enum insn_code icode;
 692       optab optab;
 693
 694       /* Check target support  */
 695       type_in = get_vectype_for_scalar_type (type_in);
 696       if (!type_in)
 697         return;
 698       if (type_out)
 699         type_out = get_vectype_for_scalar_type (type_out);
 700       else
 701         type_out = type_in;
 702       if (!type_out)
 703         return;
 704       pattern_vectype = type_out;
 705
 706       if (is_gimple_assign (pattern_stmt))
 707         code = gimple_assign_rhs_code (pattern_stmt);
 708       else
 709         {
 710           gcc_assert (is_gimple_call (pattern_stmt));
 711           code = CALL_EXPR;
 712         }
 713
 714       optab = optab_for_tree_code (code, type_in, optab_default);
 715       vec_mode = TYPE_MODE (type_in);
 716       if (!optab
 717           || (icode = optab_handler (optab, vec_mode)->insn_code) ==
 718               CODE_FOR_nothing
 719           || (insn_data[icode].operand[0].mode != TYPE_MODE (type_out)))
 720         return;
 721     }
 722
 723   /* Found a vectorizable pattern.  */
 724   if (vect_print_dump_info (REPORT_DETAILS))
 725     {
 726       fprintf (vect_dump, "pattern recognized: ");
 727       print_gimple_stmt (vect_dump, pattern_stmt, 0, TDF_SLIM);
 728     }
 729
 730   /* Mark the stmts that are involved in the pattern. */
 731   gsi_insert_before (&si, pattern_stmt, GSI_SAME_STMT);
 732   set_vinfo_for_stmt (pattern_stmt,
 733                       new_stmt_vec_info (pattern_stmt, loop_vinfo, NULL));
 734   pattern_stmt_info = vinfo_for_stmt (pattern_stmt);
 735
 736   STMT_VINFO_RELATED_STMT (pattern_stmt_info) = stmt;
 737   STMT_VINFO_DEF_TYPE (pattern_stmt_info) = STMT_VINFO_DEF_TYPE (stmt_info);
 738   STMT_VINFO_VECTYPE (pattern_stmt_info) = pattern_vectype;
 739   STMT_VINFO_IN_PATTERN_P (stmt_info) = true;
 740   STMT_VINFO_RELATED_STMT (stmt_info) = pattern_stmt;
 741
 742   /* Patterns cannot be vectorized using SLP, because they change the order of
 743      computation.  */
 744   for (i = 0; VEC_iterate (gimple, LOOP_VINFO_REDUCTIONS (loop_vinfo), i,
 745                            next);
 746        i++)
 747     if (next == stmt)
 748       VEC_ordered_remove (gimple, LOOP_VINFO_REDUCTIONS (loop_vinfo), i);
 749 }
 750
 751
 752 /* Function vect_pattern_recog
 753
 754    Input:
 755    LOOP_VINFO - a struct_loop_info of a loop in which we want to look for
 756         computation idioms.
 757
 758    Output - for each computation idiom that is detected we insert a new stmt
 759         that provides the same functionality and that can be vectorized. We
 760         also record some information in the struct_stmt_info of the relevant
 761         stmts, as explained below:
 762
 763    At the entry to this function we have the following stmts, with the
 764    following initial value in the STMT_VINFO fields:
 765
 766          stmt                     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          S4: a_0 = ..use(a_1)..         -       -               -
 771          S5: ... = ..use(a_0)..         -       -               -
 772
 773    Say the sequence {S1,S2,S3,S4} was detected as a pattern that can be
 774    represented by a single stmt. We then:
 775    - create a new stmt S6 that will replace the pattern.
 776    - insert the new stmt S6 before the last stmt in the pattern
 777    - fill in the STMT_VINFO fields as follows:
 778
 779                                   in_pattern_p  related_stmt    vec_stmt
 780          S1: a_i = ....                 -       -               -
 781          S2: a_2 = ..use(a_i)..         -       -               -
 782          S3: a_1 = ..use(a_2)..         -       -               -
 783        > S6: a_new = ....               -       S4              -
 784          S4: a_0 = ..use(a_1)..         true    S6              -
 785          S5: ... = ..use(a_0)..         -       -               -
 786
 787    (the last stmt in the pattern (S4) and the new pattern stmt (S6) point
 788     to each other through the RELATED_STMT field).
 789
 790    S6 will be marked as relevant in vect_mark_stmts_to_be_vectorized instead
 791    of S4 because it will replace all its uses.  Stmts {S1,S2,S3} will
 792    remain irrelevant unless used by stmts other than S4.
 793
 794    If vectorization succeeds, vect_transform_stmt will skip over {S1,S2,S3}
 795    (because they are marked as irrelevant). It will vectorize S6, and record
 796    a pointer to the new vector stmt VS6 both from S6 (as usual), and also
 797    from S4. We do that so that when we get to vectorizing stmts that use the
 798    def of S4 (like S5 that uses a_0), we'll know where to take the relevant
 799    vector-def from. S4 will be skipped, and S5 will be vectorized as usual:
 800
 801                                   in_pattern_p  related_stmt    vec_stmt
 802          S1: a_i = ....                 -       -               -
 803          S2: a_2 = ..use(a_i)..         -       -               -
 804          S3: a_1 = ..use(a_2)..         -       -               -
 805        > VS6: va_new = ....             -       -               -
 806          S6: a_new = ....               -       S4              VS6
 807          S4: a_0 = ..use(a_1)..         true    S6              VS6
 808        > VS5: ... = ..vuse(va_new)..    -       -               -
 809          S5: ... = ..use(a_0)..         -       -               -
 810
 811    DCE could then get rid of {S1,S2,S3,S4,S5,S6} (if their defs are not used
 812    elsewhere), and we'll end up with:
 813
 814         VS6: va_new = ....
 815         VS5: ... = ..vuse(va_new)..
 816
 817    If vectorization does not succeed, DCE will clean S6 away (its def is
 818    not used), and we'll end up with the original sequence.
 819 */
 820
 821 void
 822 vect_pattern_recog (loop_vec_info loop_vinfo)
 823 {
 824   struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
 825   basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
 826   unsigned int nbbs = loop->num_nodes;
 827   gimple_stmt_iterator si;
 828   unsigned int i, j;
 829   gimple (* vect_recog_func_ptr) (gimple, tree *, tree *);
 830
 831   if (vect_print_dump_info (REPORT_DETAILS))
 832     fprintf (vect_dump, "=== vect_pattern_recog ===");
 833
 834   /* Scan through the loop stmts, applying the pattern recognition
 835      functions starting at each stmt visited:  */
 836   for (i = 0; i < nbbs; i++)
 837     {
 838       basic_block bb = bbs[i];
 839       for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
 840         {
 841           /* Scan over all generic vect_recog_xxx_pattern functions.  */
 842           for (j = 0; j < NUM_PATTERNS; j++)
 843             {
 844               vect_recog_func_ptr = vect_vect_recog_func_ptrs[j];
 845               vect_pattern_recog_1 (vect_recog_func_ptr, si);
 846             }
 847         }
 848     }
 849 }