1 /* Analysis Utilities for Loop Vectorization.
2 Copyright (C) 2006, 2007 Free Software Foundation, Inc.
3 Contributed by Dorit Nuzman <dorit@il.ibm.com>
5 This file is part of GCC.
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
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
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/>. */
23 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "diagnostic.h"
31 #include "tree-flow.h"
32 #include "tree-dump.h"
38 #include "tree-data-ref.h"
39 #include "tree-vectorizer.h"
43 /* Function prototypes */
44 static void vect_pattern_recog_1
45 (tree (* ) (tree
, tree
*, tree
*), block_stmt_iterator
);
46 static bool widened_name_p (tree
, tree
, tree
*, tree
*);
48 /* Pattern recognition functions */
49 static tree
vect_recog_widen_sum_pattern (tree
, tree
*, tree
*);
50 static tree
vect_recog_widen_mult_pattern (tree
, tree
*, tree
*);
51 static tree
vect_recog_dot_prod_pattern (tree
, tree
*, tree
*);
52 static tree
vect_recog_pow_pattern (tree
, tree
*, tree
*);
53 static vect_recog_func_ptr vect_vect_recog_func_ptrs
[NUM_PATTERNS
] = {
54 vect_recog_widen_mult_pattern
,
55 vect_recog_widen_sum_pattern
,
56 vect_recog_dot_prod_pattern
,
57 vect_recog_pow_pattern
};
60 /* Function widened_name_p
62 Check whether NAME, an ssa-name used in USE_STMT,
63 is a result of a type-promotion, such that:
64 DEF_STMT: NAME = NOP (name0)
65 where the type of name0 (HALF_TYPE) is smaller than the type of NAME.
69 widened_name_p (tree name
, tree use_stmt
, tree
*half_type
, tree
*def_stmt
)
72 loop_vec_info loop_vinfo
;
73 stmt_vec_info stmt_vinfo
;
75 tree type
= TREE_TYPE (name
);
77 enum vect_def_type dt
;
80 stmt_vinfo
= vinfo_for_stmt (use_stmt
);
81 loop_vinfo
= STMT_VINFO_LOOP_VINFO (stmt_vinfo
);
83 if (!vect_is_simple_use (name
, loop_vinfo
, def_stmt
, &def
, &dt
))
86 if (dt
!= vect_loop_def
87 && dt
!= vect_invariant_def
&& dt
!= vect_constant_def
)
93 if (TREE_CODE (*def_stmt
) != GIMPLE_MODIFY_STMT
)
96 expr
= GIMPLE_STMT_OPERAND (*def_stmt
, 1);
97 if (TREE_CODE (expr
) != NOP_EXPR
)
100 oprnd0
= TREE_OPERAND (expr
, 0);
102 *half_type
= TREE_TYPE (oprnd0
);
103 if (!INTEGRAL_TYPE_P (type
) || !INTEGRAL_TYPE_P (*half_type
)
104 || (TYPE_UNSIGNED (type
) != TYPE_UNSIGNED (*half_type
))
105 || (TYPE_PRECISION (type
) < (TYPE_PRECISION (*half_type
) * 2)))
108 if (!vect_is_simple_use (oprnd0
, loop_vinfo
, &dummy
, &dummy
, &dt
))
115 /* Function vect_recog_dot_prod_pattern
117 Try to find the following pattern:
123 sum_0 = phi <init, sum_1>
126 S3 x_T = (TYPE1) x_t;
127 S4 y_T = (TYPE1) y_t;
129 [S6 prod = (TYPE2) prod; #optional]
130 S7 sum_1 = prod + sum_0;
132 where 'TYPE1' is exactly double the size of type 'type', and 'TYPE2' is the
133 same size of 'TYPE1' or bigger. This is a special case of a reduction
138 * LAST_STMT: A stmt from which the pattern search begins. In the example,
139 when this function is called with S7, the pattern {S3,S4,S5,S6,S7} will be
144 * TYPE_IN: The type of the input arguments to the pattern.
146 * TYPE_OUT: The type of the output of this pattern.
148 * Return value: A new stmt that will be used to replace the sequence of
149 stmts that constitute the pattern. In this case it will be:
150 WIDEN_DOT_PRODUCT <x_t, y_t, sum_0>
152 Note: The dot-prod idiom is a widening reduction pattern that is
153 vectorized without preserving all the intermediate results. It
154 produces only N/2 (widened) results (by summing up pairs of
155 intermediate results) rather than all N results. Therefore, we
156 cannot allow this pattern when we want to get all the results and in
157 the correct order (as is the case when this computation is in an
158 inner-loop nested in an outer-loop that us being vectorized). */
161 vect_recog_dot_prod_pattern (tree last_stmt
, tree
*type_in
, tree
*type_out
)
165 tree oprnd00
, oprnd01
;
166 stmt_vec_info stmt_vinfo
= vinfo_for_stmt (last_stmt
);
167 tree type
, half_type
;
170 loop_vec_info loop_info
= STMT_VINFO_LOOP_VINFO (stmt_vinfo
);
171 struct loop
*loop
= LOOP_VINFO_LOOP (loop_info
);
173 if (TREE_CODE (last_stmt
) != GIMPLE_MODIFY_STMT
)
176 expr
= GIMPLE_STMT_OPERAND (last_stmt
, 1);
177 type
= TREE_TYPE (expr
);
179 /* Look for the following pattern
183 DDPROD = (TYPE2) DPROD;
184 sum_1 = DDPROD + sum_0;
186 - DX is double the size of X
187 - DY is double the size of Y
188 - DX, DY, DPROD all have the same type
189 - sum is the same size of DPROD or bigger
190 - sum has been recognized as a reduction variable.
192 This is equivalent to:
193 DPROD = X w* Y; #widen mult
194 sum_1 = DPROD w+ sum_0; #widen summation
196 DPROD = X w* Y; #widen mult
197 sum_1 = DPROD + sum_0; #summation
200 /* Starting from LAST_STMT, follow the defs of its uses in search
201 of the above pattern. */
203 if (TREE_CODE (expr
) != PLUS_EXPR
)
206 if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo
))
208 /* Has been detected as widening-summation? */
210 stmt
= STMT_VINFO_RELATED_STMT (stmt_vinfo
);
211 expr
= GIMPLE_STMT_OPERAND (stmt
, 1);
212 type
= TREE_TYPE (expr
);
213 if (TREE_CODE (expr
) != WIDEN_SUM_EXPR
)
215 oprnd0
= TREE_OPERAND (expr
, 0);
216 oprnd1
= TREE_OPERAND (expr
, 1);
217 half_type
= TREE_TYPE (oprnd0
);
223 if (STMT_VINFO_DEF_TYPE (stmt_vinfo
) != vect_reduction_def
)
225 oprnd0
= TREE_OPERAND (expr
, 0);
226 oprnd1
= TREE_OPERAND (expr
, 1);
227 if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0
)) != TYPE_MAIN_VARIANT (type
)
228 || TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1
)) != TYPE_MAIN_VARIANT (type
))
232 if (widened_name_p (oprnd0
, stmt
, &half_type
, &def_stmt
))
235 expr
= GIMPLE_STMT_OPERAND (stmt
, 1);
236 oprnd0
= TREE_OPERAND (expr
, 0);
242 /* So far so good. Since last_stmt was detected as a (summation) reduction,
243 we know that oprnd1 is the reduction variable (defined by a loop-header
244 phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
245 Left to check that oprnd0 is defined by a (widen_)mult_expr */
247 prod_type
= half_type
;
248 stmt
= SSA_NAME_DEF_STMT (oprnd0
);
249 /* FORNOW. Can continue analyzing the def-use chain when this stmt in a phi
250 inside the loop (in case we are analyzing an outer-loop). */
251 if (TREE_CODE (stmt
) != GIMPLE_MODIFY_STMT
)
253 stmt_vinfo
= vinfo_for_stmt (stmt
);
254 gcc_assert (stmt_vinfo
);
255 if (STMT_VINFO_DEF_TYPE (stmt_vinfo
) != vect_loop_def
)
257 expr
= GIMPLE_STMT_OPERAND (stmt
, 1);
258 if (TREE_CODE (expr
) != MULT_EXPR
)
260 if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo
))
262 /* Has been detected as a widening multiplication? */
264 stmt
= STMT_VINFO_RELATED_STMT (stmt_vinfo
);
265 expr
= GIMPLE_STMT_OPERAND (stmt
, 1);
266 if (TREE_CODE (expr
) != WIDEN_MULT_EXPR
)
268 stmt_vinfo
= vinfo_for_stmt (stmt
);
269 gcc_assert (stmt_vinfo
);
270 gcc_assert (STMT_VINFO_DEF_TYPE (stmt_vinfo
) == vect_loop_def
);
271 oprnd00
= TREE_OPERAND (expr
, 0);
272 oprnd01
= TREE_OPERAND (expr
, 1);
276 tree half_type0
, half_type1
;
280 oprnd0
= TREE_OPERAND (expr
, 0);
281 oprnd1
= TREE_OPERAND (expr
, 1);
282 if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0
))
283 != TYPE_MAIN_VARIANT (prod_type
)
284 || TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1
))
285 != TYPE_MAIN_VARIANT (prod_type
))
287 if (!widened_name_p (oprnd0
, stmt
, &half_type0
, &def_stmt
))
289 oprnd00
= TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt
, 1), 0);
290 if (!widened_name_p (oprnd1
, stmt
, &half_type1
, &def_stmt
))
292 oprnd01
= TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt
, 1), 0);
293 if (TYPE_MAIN_VARIANT (half_type0
) != TYPE_MAIN_VARIANT (half_type1
))
295 if (TYPE_PRECISION (prod_type
) != TYPE_PRECISION (half_type0
) * 2)
299 half_type
= TREE_TYPE (oprnd00
);
300 *type_in
= half_type
;
303 /* Pattern detected. Create a stmt to be used to replace the pattern: */
304 pattern_expr
= build3 (DOT_PROD_EXPR
, type
, oprnd00
, oprnd01
, oprnd1
);
305 if (vect_print_dump_info (REPORT_DETAILS
))
307 fprintf (vect_dump
, "vect_recog_dot_prod_pattern: detected: ");
308 print_generic_expr (vect_dump
, pattern_expr
, TDF_SLIM
);
311 /* We don't allow changing the order of the computation in the inner-loop
312 when doing outer-loop vectorization. */
313 if (nested_in_vect_loop_p (loop
, last_stmt
))
315 if (vect_print_dump_info (REPORT_DETAILS
))
316 fprintf (vect_dump
, "vect_recog_dot_prod_pattern: not allowed.");
324 /* Function vect_recog_widen_mult_pattern
326 Try to find the following pattern:
329 TYPE a_T, b_T, prod_T;
335 S5 prod_T = a_T * b_T;
337 where type 'TYPE' is at least double the size of type 'type'.
341 * LAST_STMT: A stmt from which the pattern search begins. In the example,
342 when this function is called with S5, the pattern {S3,S4,S5} is be detected.
346 * TYPE_IN: The type of the input arguments to the pattern.
348 * TYPE_OUT: The type of the output of this pattern.
350 * Return value: A new stmt that will be used to replace the sequence of
351 stmts that constitute the pattern. In this case it will be:
352 WIDEN_MULT <a_t, b_t>
356 vect_recog_widen_mult_pattern (tree last_stmt
,
361 tree def_stmt0
, def_stmt1
;
363 tree type
, half_type0
, half_type1
;
367 enum tree_code dummy_code
;
369 if (TREE_CODE (last_stmt
) != GIMPLE_MODIFY_STMT
)
372 expr
= GIMPLE_STMT_OPERAND (last_stmt
, 1);
373 type
= TREE_TYPE (expr
);
375 /* Starting from LAST_STMT, follow the defs of its uses in search
376 of the above pattern. */
378 if (TREE_CODE (expr
) != MULT_EXPR
)
381 oprnd0
= TREE_OPERAND (expr
, 0);
382 oprnd1
= TREE_OPERAND (expr
, 1);
383 if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0
)) != TYPE_MAIN_VARIANT (type
)
384 || TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1
)) != TYPE_MAIN_VARIANT (type
))
387 /* Check argument 0 */
388 if (!widened_name_p (oprnd0
, last_stmt
, &half_type0
, &def_stmt0
))
390 oprnd0
= TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt0
, 1), 0);
392 /* Check argument 1 */
393 if (!widened_name_p (oprnd1
, last_stmt
, &half_type1
, &def_stmt1
))
395 oprnd1
= TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt1
, 1), 0);
397 if (TYPE_MAIN_VARIANT (half_type0
) != TYPE_MAIN_VARIANT (half_type1
))
400 /* Pattern detected. */
401 if (vect_print_dump_info (REPORT_DETAILS
))
402 fprintf (vect_dump
, "vect_recog_widen_mult_pattern: detected: ");
404 /* Check target support */
405 vectype
= get_vectype_for_scalar_type (half_type0
);
407 || !supportable_widening_operation (WIDEN_MULT_EXPR
, last_stmt
, vectype
,
408 &dummy
, &dummy
, &dummy_code
,
413 *type_out
= NULL_TREE
;
415 /* Pattern supported. Create a stmt to be used to replace the pattern: */
416 pattern_expr
= build2 (WIDEN_MULT_EXPR
, type
, oprnd0
, oprnd1
);
417 if (vect_print_dump_info (REPORT_DETAILS
))
418 print_generic_expr (vect_dump
, pattern_expr
, TDF_SLIM
);
423 /* Function vect_recog_pow_pattern
425 Try to find the following pattern:
429 with POW being one of pow, powf, powi, powif and N being
434 * LAST_STMT: A stmt from which the pattern search begins.
438 * TYPE_IN: The type of the input arguments to the pattern.
440 * TYPE_OUT: The type of the output of this pattern.
442 * Return value: A new stmt that will be used to replace the sequence of
443 stmts that constitute the pattern. In this case it will be:
450 vect_recog_pow_pattern (tree last_stmt
, tree
*type_in
, tree
*type_out
)
456 if (TREE_CODE (last_stmt
) != GIMPLE_MODIFY_STMT
)
459 expr
= GIMPLE_STMT_OPERAND (last_stmt
, 1);
460 type
= TREE_TYPE (expr
);
462 if (TREE_CODE (expr
) != CALL_EXPR
)
465 fn
= get_callee_fndecl (expr
);
466 switch (DECL_FUNCTION_CODE (fn
))
472 base
= CALL_EXPR_ARG (expr
, 0);
473 exp
= CALL_EXPR_ARG (expr
, 1);
474 if (TREE_CODE (exp
) != REAL_CST
475 && TREE_CODE (exp
) != INTEGER_CST
)
483 /* We now have a pow or powi builtin function call with a constant
486 *type_out
= NULL_TREE
;
488 /* Catch squaring. */
489 if ((host_integerp (exp
, 0)
490 && tree_low_cst (exp
, 0) == 2)
491 || (TREE_CODE (exp
) == REAL_CST
492 && REAL_VALUES_EQUAL (TREE_REAL_CST (exp
), dconst2
)))
494 *type_in
= TREE_TYPE (base
);
495 return build2 (MULT_EXPR
, TREE_TYPE (base
), base
, base
);
498 /* Catch square root. */
499 if (TREE_CODE (exp
) == REAL_CST
500 && REAL_VALUES_EQUAL (TREE_REAL_CST (exp
), dconsthalf
))
502 tree newfn
= mathfn_built_in (TREE_TYPE (base
), BUILT_IN_SQRT
);
503 *type_in
= get_vectype_for_scalar_type (TREE_TYPE (base
));
506 newfn
= build_call_expr (newfn
, 1, base
);
507 if (vectorizable_function (newfn
, *type_in
, *type_in
) != NULL_TREE
)
516 /* Function vect_recog_widen_sum_pattern
518 Try to find the following pattern:
521 TYPE x_T, sum = init;
523 sum_0 = phi <init, sum_1>
526 S3 sum_1 = x_T + sum_0;
528 where type 'TYPE' is at least double the size of type 'type', i.e - we're
529 summing elements of type 'type' into an accumulator of type 'TYPE'. This is
530 a special case of a reduction computation.
534 * LAST_STMT: A stmt from which the pattern search begins. In the example,
535 when this function is called with S3, the pattern {S2,S3} will be detected.
539 * TYPE_IN: The type of the input arguments to the pattern.
541 * TYPE_OUT: The type of the output of this pattern.
543 * Return value: A new stmt that will be used to replace the sequence of
544 stmts that constitute the pattern. In this case it will be:
545 WIDEN_SUM <x_t, sum_0>
547 Note: The widening-sum idiom is a widening reduction pattern that is
548 vectorized without preserving all the intermediate results. It
549 produces only N/2 (widened) results (by summing up pairs of
550 intermediate results) rather than all N results. Therefore, we
551 cannot allow this pattern when we want to get all the results and in
552 the correct order (as is the case when this computation is in an
553 inner-loop nested in an outer-loop that us being vectorized). */
556 vect_recog_widen_sum_pattern (tree last_stmt
, tree
*type_in
, tree
*type_out
)
560 stmt_vec_info stmt_vinfo
= vinfo_for_stmt (last_stmt
);
561 tree type
, half_type
;
563 loop_vec_info loop_info
= STMT_VINFO_LOOP_VINFO (stmt_vinfo
);
564 struct loop
*loop
= LOOP_VINFO_LOOP (loop_info
);
566 if (TREE_CODE (last_stmt
) != GIMPLE_MODIFY_STMT
)
569 expr
= GIMPLE_STMT_OPERAND (last_stmt
, 1);
570 type
= TREE_TYPE (expr
);
572 /* Look for the following pattern
575 In which DX is at least double the size of X, and sum_1 has been
576 recognized as a reduction variable.
579 /* Starting from LAST_STMT, follow the defs of its uses in search
580 of the above pattern. */
582 if (TREE_CODE (expr
) != PLUS_EXPR
)
585 if (STMT_VINFO_DEF_TYPE (stmt_vinfo
) != vect_reduction_def
)
588 oprnd0
= TREE_OPERAND (expr
, 0);
589 oprnd1
= TREE_OPERAND (expr
, 1);
590 if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0
)) != TYPE_MAIN_VARIANT (type
)
591 || TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1
)) != TYPE_MAIN_VARIANT (type
))
594 /* So far so good. Since last_stmt was detected as a (summation) reduction,
595 we know that oprnd1 is the reduction variable (defined by a loop-header
596 phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
597 Left to check that oprnd0 is defined by a cast from type 'type' to type
600 if (!widened_name_p (oprnd0
, last_stmt
, &half_type
, &stmt
))
603 oprnd0
= TREE_OPERAND (GIMPLE_STMT_OPERAND (stmt
, 1), 0);
604 *type_in
= half_type
;
607 /* Pattern detected. Create a stmt to be used to replace the pattern: */
608 pattern_expr
= build2 (WIDEN_SUM_EXPR
, type
, oprnd0
, oprnd1
);
609 if (vect_print_dump_info (REPORT_DETAILS
))
611 fprintf (vect_dump
, "vect_recog_widen_sum_pattern: detected: ");
612 print_generic_expr (vect_dump
, pattern_expr
, TDF_SLIM
);
615 /* We don't allow changing the order of the computation in the inner-loop
616 when doing outer-loop vectorization. */
617 if (nested_in_vect_loop_p (loop
, last_stmt
))
619 if (vect_print_dump_info (REPORT_DETAILS
))
620 fprintf (vect_dump
, "vect_recog_widen_sum_pattern: not allowed.");
628 /* Function vect_pattern_recog_1
631 PATTERN_RECOG_FUNC: A pointer to a function that detects a certain
633 STMT: A stmt from which the pattern search should start.
635 If PATTERN_RECOG_FUNC successfully detected the pattern, it creates an
636 expression that computes the same functionality and can be used to
637 replace the sequence of stmts that are involved in the pattern.
640 This function checks if the expression returned by PATTERN_RECOG_FUNC is
641 supported in vector form by the target. We use 'TYPE_IN' to obtain the
642 relevant vector type. If 'TYPE_IN' is already a vector type, then this
643 indicates that target support had already been checked by PATTERN_RECOG_FUNC.
644 If 'TYPE_OUT' is also returned by PATTERN_RECOG_FUNC, we check that it fits
645 to the available target pattern.
647 This function also does some bookkeeping, as explained in the documentation
648 for vect_recog_pattern. */
651 vect_pattern_recog_1 (
652 tree (* vect_recog_func
) (tree
, tree
*, tree
*),
653 block_stmt_iterator si
)
655 tree stmt
= bsi_stmt (si
);
656 stmt_vec_info stmt_info
= vinfo_for_stmt (stmt
);
657 stmt_vec_info pattern_stmt_info
;
658 loop_vec_info loop_vinfo
= STMT_VINFO_LOOP_VINFO (stmt_info
);
660 tree pattern_vectype
;
661 tree type_in
, type_out
;
667 pattern_expr
= (* vect_recog_func
) (stmt
, &type_in
, &type_out
);
671 if (VECTOR_MODE_P (TYPE_MODE (type_in
)))
673 /* No need to check target support (already checked by the pattern
674 recognition function). */
675 pattern_vectype
= type_in
;
679 enum tree_code vec_mode
;
680 enum insn_code icode
;
683 /* Check target support */
684 pattern_vectype
= get_vectype_for_scalar_type (type_in
);
685 if (!pattern_vectype
)
688 optab
= optab_for_tree_code (TREE_CODE (pattern_expr
), pattern_vectype
);
689 vec_mode
= TYPE_MODE (pattern_vectype
);
691 || (icode
= optab_handler (optab
, vec_mode
)->insn_code
) ==
694 && (!get_vectype_for_scalar_type (type_out
)
695 || (insn_data
[icode
].operand
[0].mode
!=
696 TYPE_MODE (get_vectype_for_scalar_type (type_out
))))))
700 /* Found a vectorizable pattern. */
701 if (vect_print_dump_info (REPORT_DETAILS
))
703 fprintf (vect_dump
, "pattern recognized: ");
704 print_generic_expr (vect_dump
, pattern_expr
, TDF_SLIM
);
707 /* Mark the stmts that are involved in the pattern,
708 create a new stmt to express the pattern and insert it. */
709 code
= TREE_CODE (pattern_expr
);
710 pattern_type
= TREE_TYPE (pattern_expr
);
711 var
= create_tmp_var (pattern_type
, "patt");
712 add_referenced_var (var
);
713 var_name
= make_ssa_name (var
, NULL_TREE
);
714 pattern_expr
= build_gimple_modify_stmt (var_name
, pattern_expr
);
715 SSA_NAME_DEF_STMT (var_name
) = pattern_expr
;
716 bsi_insert_before (&si
, pattern_expr
, BSI_SAME_STMT
);
717 ann
= stmt_ann (pattern_expr
);
718 set_stmt_info (ann
, new_stmt_vec_info (pattern_expr
, loop_vinfo
));
719 pattern_stmt_info
= vinfo_for_stmt (pattern_expr
);
721 STMT_VINFO_RELATED_STMT (pattern_stmt_info
) = stmt
;
722 STMT_VINFO_DEF_TYPE (pattern_stmt_info
) = STMT_VINFO_DEF_TYPE (stmt_info
);
723 STMT_VINFO_VECTYPE (pattern_stmt_info
) = pattern_vectype
;
724 STMT_VINFO_IN_PATTERN_P (stmt_info
) = true;
725 STMT_VINFO_RELATED_STMT (stmt_info
) = pattern_expr
;
731 /* Function vect_pattern_recog
734 LOOP_VINFO - a struct_loop_info of a loop in which we want to look for
737 Output - for each computation idiom that is detected we insert a new stmt
738 that provides the same functionality and that can be vectorized. We
739 also record some information in the struct_stmt_info of the relevant
740 stmts, as explained below:
742 At the entry to this function we have the following stmts, with the
743 following initial value in the STMT_VINFO fields:
745 stmt in_pattern_p related_stmt vec_stmt
747 S2: a_2 = ..use(a_i).. - - -
748 S3: a_1 = ..use(a_2).. - - -
749 S4: a_0 = ..use(a_1).. - - -
750 S5: ... = ..use(a_0).. - - -
752 Say the sequence {S1,S2,S3,S4} was detected as a pattern that can be
753 represented by a single stmt. We then:
754 - create a new stmt S6 that will replace the pattern.
755 - insert the new stmt S6 before the last stmt in the pattern
756 - fill in the STMT_VINFO fields as follows:
758 in_pattern_p related_stmt vec_stmt
760 S2: a_2 = ..use(a_i).. - - -
761 S3: a_1 = ..use(a_2).. - - -
762 > S6: a_new = .... - S4 -
763 S4: a_0 = ..use(a_1).. true S6 -
764 S5: ... = ..use(a_0).. - - -
766 (the last stmt in the pattern (S4) and the new pattern stmt (S6) point
767 to each other through the RELATED_STMT field).
769 S6 will be marked as relevant in vect_mark_stmts_to_be_vectorized instead
770 of S4 because it will replace all its uses. Stmts {S1,S2,S3} will
771 remain irrelevant unless used by stmts other than S4.
773 If vectorization succeeds, vect_transform_stmt will skip over {S1,S2,S3}
774 (because they are marked as irrelevant). It will vectorize S6, and record
775 a pointer to the new vector stmt VS6 both from S6 (as usual), and also
776 from S4. We do that so that when we get to vectorizing stmts that use the
777 def of S4 (like S5 that uses a_0), we'll know where to take the relevant
778 vector-def from. S4 will be skipped, and S5 will be vectorized as usual:
780 in_pattern_p related_stmt vec_stmt
782 S2: a_2 = ..use(a_i).. - - -
783 S3: a_1 = ..use(a_2).. - - -
784 > VS6: va_new = .... - - -
785 S6: a_new = .... - S4 VS6
786 S4: a_0 = ..use(a_1).. true S6 VS6
787 > VS5: ... = ..vuse(va_new).. - - -
788 S5: ... = ..use(a_0).. - - -
790 DCE could then get rid of {S1,S2,S3,S4,S5,S6} (if their defs are not used
791 elsewhere), and we'll end up with:
794 VS5: ... = ..vuse(va_new)..
796 If vectorization does not succeed, DCE will clean S6 away (its def is
797 not used), and we'll end up with the original sequence.
801 vect_pattern_recog (loop_vec_info loop_vinfo
)
803 struct loop
*loop
= LOOP_VINFO_LOOP (loop_vinfo
);
804 basic_block
*bbs
= LOOP_VINFO_BBS (loop_vinfo
);
805 unsigned int nbbs
= loop
->num_nodes
;
806 block_stmt_iterator si
;
809 tree (* vect_recog_func_ptr
) (tree
, tree
*, tree
*);
811 if (vect_print_dump_info (REPORT_DETAILS
))
812 fprintf (vect_dump
, "=== vect_pattern_recog ===");
814 /* Scan through the loop stmts, applying the pattern recognition
815 functions starting at each stmt visited: */
816 for (i
= 0; i
< nbbs
; i
++)
818 basic_block bb
= bbs
[i
];
819 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
821 stmt
= bsi_stmt (si
);
823 /* Scan over all generic vect_recog_xxx_pattern functions. */
824 for (j
= 0; j
< NUM_PATTERNS
; j
++)
826 vect_recog_func_ptr
= vect_vect_recog_func_ptrs
[j
];
827 vect_pattern_recog_1 (vect_recog_func_ptr
, si
);