1 /* Analysis Utilities for Loop Vectorization.
2 Copyright (C) 2006 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 2, 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 COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
24 #include "coretypes.h"
30 #include "basic-block.h"
31 #include "diagnostic.h"
32 #include "tree-flow.h"
33 #include "tree-dump.h"
39 #include "tree-data-ref.h"
40 #include "tree-vectorizer.h"
44 /* Function prototypes */
45 static void vect_pattern_recog_1
46 (tree (* ) (tree
, tree
*, tree
*), block_stmt_iterator
);
47 static bool widened_name_p (tree
, tree
, tree
*, tree
*);
49 /* Pattern recognition functions */
50 static tree
vect_recog_widen_sum_pattern (tree
, tree
*, tree
*);
51 static tree
vect_recog_widen_mult_pattern (tree
, tree
*, tree
*);
52 static tree
vect_recog_dot_prod_pattern (tree
, tree
*, tree
*);
53 static tree
vect_recog_pow_pattern (tree
, tree
*, tree
*);
54 static vect_recog_func_ptr vect_vect_recog_func_ptrs
[NUM_PATTERNS
] = {
55 vect_recog_widen_mult_pattern
,
56 vect_recog_widen_sum_pattern
,
57 vect_recog_dot_prod_pattern
,
58 vect_recog_pow_pattern
};
61 /* Function widened_name_p
63 Check whether NAME, an ssa-name used in USE_STMT,
64 is a result of a type-promotion, such that:
65 DEF_STMT: NAME = NOP (name0)
66 where the type of name0 (HALF_TYPE) is smaller than the type of NAME.
70 widened_name_p (tree name
, tree use_stmt
, tree
*half_type
, tree
*def_stmt
)
73 loop_vec_info loop_vinfo
;
74 stmt_vec_info stmt_vinfo
;
76 tree type
= TREE_TYPE (name
);
78 enum vect_def_type dt
;
81 stmt_vinfo
= vinfo_for_stmt (use_stmt
);
82 loop_vinfo
= STMT_VINFO_LOOP_VINFO (stmt_vinfo
);
84 if (!vect_is_simple_use (name
, loop_vinfo
, def_stmt
, &def
, &dt
))
87 if (dt
!= vect_loop_def
88 && dt
!= vect_invariant_def
&& dt
!= vect_constant_def
)
94 if (TREE_CODE (*def_stmt
) != MODIFY_EXPR
)
97 expr
= TREE_OPERAND (*def_stmt
, 1);
98 if (TREE_CODE (expr
) != NOP_EXPR
)
101 oprnd0
= TREE_OPERAND (expr
, 0);
103 *half_type
= TREE_TYPE (oprnd0
);
104 if (!INTEGRAL_TYPE_P (type
) || !INTEGRAL_TYPE_P (*half_type
)
105 || (TYPE_UNSIGNED (type
) != TYPE_UNSIGNED (*half_type
))
106 || (TYPE_PRECISION (type
) < (TYPE_PRECISION (*half_type
) * 2)))
109 if (!vect_is_simple_use (oprnd0
, loop_vinfo
, &dummy
, &dummy
, &dt
))
112 if (dt
!= vect_invariant_def
&& dt
!= vect_constant_def
113 && dt
!= vect_loop_def
)
120 /* Function vect_recog_dot_prod_pattern
122 Try to find the following pattern:
128 sum_0 = phi <init, sum_1>
131 S3 x_T = (TYPE1) x_t;
132 S4 y_T = (TYPE1) y_t;
134 [S6 prod = (TYPE2) prod; #optional]
135 S7 sum_1 = prod + sum_0;
137 where 'TYPE1' is exactly double the size of type 'type', and 'TYPE2' is the
138 same size of 'TYPE1' or bigger. This is a special case of a reduction
143 * LAST_STMT: A stmt from which the pattern search begins. In the example,
144 when this function is called with S7, the pattern {S3,S4,S5,S6,S7} will be
149 * TYPE_IN: The type of the input arguments to the pattern.
151 * TYPE_OUT: The type of the output of this pattern.
153 * Return value: A new stmt that will be used to replace the sequence of
154 stmts that constitute the pattern. In this case it will be:
155 WIDEN_DOT_PRODUCT <x_t, y_t, sum_0>
159 vect_recog_dot_prod_pattern (tree last_stmt
, tree
*type_in
, tree
*type_out
)
163 tree oprnd00
, oprnd01
;
164 stmt_vec_info stmt_vinfo
= vinfo_for_stmt (last_stmt
);
165 tree type
, half_type
;
169 if (TREE_CODE (last_stmt
) != MODIFY_EXPR
)
172 expr
= TREE_OPERAND (last_stmt
, 1);
173 type
= TREE_TYPE (expr
);
175 /* Look for the following pattern
179 DDPROD = (TYPE2) DPROD;
180 sum_1 = DDPROD + sum_0;
182 - DX is double the size of X
183 - DY is double the size of Y
184 - DX, DY, DPROD all have the same type
185 - sum is the same size of DPROD or bigger
186 - sum has been recognized as a reduction variable.
188 This is equivalent to:
189 DPROD = X w* Y; #widen mult
190 sum_1 = DPROD w+ sum_0; #widen summation
192 DPROD = X w* Y; #widen mult
193 sum_1 = DPROD + sum_0; #summation
196 /* Starting from LAST_STMT, follow the defs of its uses in search
197 of the above pattern. */
199 if (TREE_CODE (expr
) != PLUS_EXPR
)
202 if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo
))
204 /* Has been detected as widening-summation? */
206 stmt
= STMT_VINFO_RELATED_STMT (stmt_vinfo
);
207 expr
= TREE_OPERAND (stmt
, 1);
208 type
= TREE_TYPE (expr
);
209 if (TREE_CODE (expr
) != WIDEN_SUM_EXPR
)
211 oprnd0
= TREE_OPERAND (expr
, 0);
212 oprnd1
= TREE_OPERAND (expr
, 1);
213 half_type
= TREE_TYPE (oprnd0
);
219 if (STMT_VINFO_DEF_TYPE (stmt_vinfo
) != vect_reduction_def
)
221 oprnd0
= TREE_OPERAND (expr
, 0);
222 oprnd1
= TREE_OPERAND (expr
, 1);
223 if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0
)) != TYPE_MAIN_VARIANT (type
)
224 || TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1
)) != TYPE_MAIN_VARIANT (type
))
228 if (widened_name_p (oprnd0
, stmt
, &half_type
, &def_stmt
))
231 expr
= TREE_OPERAND (stmt
, 1);
232 oprnd0
= TREE_OPERAND (expr
, 0);
238 /* So far so good. Since last_stmt was detected as a (summation) reduction,
239 we know that oprnd1 is the reduction variable (defined by a loop-header
240 phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
241 Left to check that oprnd0 is defined by a (widen_)mult_expr */
243 prod_type
= half_type
;
244 stmt
= SSA_NAME_DEF_STMT (oprnd0
);
246 stmt_vinfo
= vinfo_for_stmt (stmt
);
247 gcc_assert (stmt_vinfo
);
248 if (STMT_VINFO_DEF_TYPE (stmt_vinfo
) != vect_loop_def
)
250 expr
= TREE_OPERAND (stmt
, 1);
251 if (TREE_CODE (expr
) != MULT_EXPR
)
253 if (STMT_VINFO_IN_PATTERN_P (stmt_vinfo
))
255 /* Has been detected as a widening multiplication? */
257 stmt
= STMT_VINFO_RELATED_STMT (stmt_vinfo
);
258 expr
= TREE_OPERAND (stmt
, 1);
259 if (TREE_CODE (expr
) != WIDEN_MULT_EXPR
)
261 stmt_vinfo
= vinfo_for_stmt (stmt
);
262 gcc_assert (stmt_vinfo
);
263 gcc_assert (STMT_VINFO_DEF_TYPE (stmt_vinfo
) == vect_loop_def
);
264 oprnd00
= TREE_OPERAND (expr
, 0);
265 oprnd01
= TREE_OPERAND (expr
, 1);
269 tree half_type0
, half_type1
;
273 oprnd0
= TREE_OPERAND (expr
, 0);
274 oprnd1
= TREE_OPERAND (expr
, 1);
275 if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0
))
276 != TYPE_MAIN_VARIANT (prod_type
)
277 || TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1
))
278 != TYPE_MAIN_VARIANT (prod_type
))
280 if (!widened_name_p (oprnd0
, stmt
, &half_type0
, &def_stmt
))
282 oprnd00
= TREE_OPERAND (TREE_OPERAND (def_stmt
, 1), 0);
283 if (!widened_name_p (oprnd1
, stmt
, &half_type1
, &def_stmt
))
285 oprnd01
= TREE_OPERAND (TREE_OPERAND (def_stmt
, 1), 0);
286 if (TYPE_MAIN_VARIANT (half_type0
) != TYPE_MAIN_VARIANT (half_type1
))
288 if (TYPE_PRECISION (prod_type
) != TYPE_PRECISION (half_type0
) * 2)
292 half_type
= TREE_TYPE (oprnd00
);
293 *type_in
= half_type
;
296 /* Pattern detected. Create a stmt to be used to replace the pattern: */
297 pattern_expr
= build3 (DOT_PROD_EXPR
, type
, oprnd00
, oprnd01
, oprnd1
);
298 if (vect_print_dump_info (REPORT_DETAILS
))
300 fprintf (vect_dump
, "vect_recog_dot_prod_pattern: detected: ");
301 print_generic_expr (vect_dump
, pattern_expr
, TDF_SLIM
);
307 /* Function vect_recog_widen_mult_pattern
309 Try to find the following pattern:
312 TYPE a_T, b_T, prod_T;
318 S5 prod_T = a_T * b_T;
320 where type 'TYPE' is at least double the size of type 'type'.
324 * LAST_STMT: A stmt from which the pattern search begins. In the example,
325 when this function is called with S5, the pattern {S3,S4,S5} is be detected.
329 * TYPE_IN: The type of the input arguments to the pattern.
331 * TYPE_OUT: The type of the output of this pattern.
333 * Return value: A new stmt that will be used to replace the sequence of
334 stmts that constitute the pattern. In this case it will be:
335 WIDEN_MULT <a_t, b_t>
339 vect_recog_widen_mult_pattern (tree last_stmt
,
344 tree def_stmt0
, def_stmt1
;
346 tree type
, half_type0
, half_type1
;
350 enum tree_code dummy_code
;
352 if (TREE_CODE (last_stmt
) != MODIFY_EXPR
)
355 expr
= TREE_OPERAND (last_stmt
, 1);
356 type
= TREE_TYPE (expr
);
358 /* Starting from LAST_STMT, follow the defs of its uses in search
359 of the above pattern. */
361 if (TREE_CODE (expr
) != MULT_EXPR
)
364 oprnd0
= TREE_OPERAND (expr
, 0);
365 oprnd1
= TREE_OPERAND (expr
, 1);
366 if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0
)) != TYPE_MAIN_VARIANT (type
)
367 || TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1
)) != TYPE_MAIN_VARIANT (type
))
370 /* Check argument 0 */
371 if (!widened_name_p (oprnd0
, last_stmt
, &half_type0
, &def_stmt0
))
373 oprnd0
= TREE_OPERAND (TREE_OPERAND (def_stmt0
, 1), 0);
375 /* Check argument 1 */
376 if (!widened_name_p (oprnd1
, last_stmt
, &half_type1
, &def_stmt1
))
378 oprnd1
= TREE_OPERAND (TREE_OPERAND (def_stmt1
, 1), 0);
380 if (TYPE_MAIN_VARIANT (half_type0
) != TYPE_MAIN_VARIANT (half_type1
))
383 /* Pattern detected. */
384 if (vect_print_dump_info (REPORT_DETAILS
))
385 fprintf (vect_dump
, "vect_recog_widen_mult_pattern: detected: ");
387 /* Check target support */
388 vectype
= get_vectype_for_scalar_type (half_type0
);
389 if (!supportable_widening_operation (WIDEN_MULT_EXPR
, last_stmt
, vectype
,
390 &dummy
, &dummy
, &dummy_code
,
395 *type_out
= NULL_TREE
;
397 /* Pattern supported. Create a stmt to be used to replace the pattern: */
398 pattern_expr
= build2 (WIDEN_MULT_EXPR
, type
, oprnd0
, oprnd1
);
399 if (vect_print_dump_info (REPORT_DETAILS
))
400 print_generic_expr (vect_dump
, pattern_expr
, TDF_SLIM
);
405 /* Function vect_recog_pow_pattern
407 Try to find the following pattern:
411 with POW being one of pow, powf, powi, powif and N being
416 * LAST_STMT: A stmt from which the pattern search begins.
420 * TYPE_IN: The type of the input arguments to the pattern.
422 * TYPE_OUT: The type of the output of this pattern.
424 * Return value: A new stmt that will be used to replace the sequence of
425 stmts that constitute the pattern. In this case it will be:
432 vect_recog_pow_pattern (tree last_stmt
, tree
*type_in
, tree
*type_out
)
436 tree fn
, arglist
, base
, exp
;
438 if (TREE_CODE (last_stmt
) != MODIFY_EXPR
)
441 expr
= TREE_OPERAND (last_stmt
, 1);
442 type
= TREE_TYPE (expr
);
444 if (TREE_CODE (expr
) != CALL_EXPR
)
447 fn
= get_callee_fndecl (expr
);
448 arglist
= TREE_OPERAND (expr
, 1);
449 switch (DECL_FUNCTION_CODE (fn
))
455 base
= TREE_VALUE (arglist
);
456 exp
= TREE_VALUE (TREE_CHAIN (arglist
));
457 if (TREE_CODE (exp
) != REAL_CST
458 && TREE_CODE (exp
) != INTEGER_CST
)
466 /* We now have a pow or powi builtin function call with a constant
469 *type_in
= get_vectype_for_scalar_type (TREE_TYPE (base
));
470 *type_out
= NULL_TREE
;
472 /* Catch squaring. */
473 if ((host_integerp (exp
, 0)
474 && tree_low_cst (exp
, 0) == 2)
475 || (TREE_CODE (exp
) == REAL_CST
476 && REAL_VALUES_EQUAL (TREE_REAL_CST (exp
), dconst2
)))
477 return build2 (MULT_EXPR
, TREE_TYPE (base
), base
, base
);
479 /* Catch square root. */
480 if (TREE_CODE (exp
) == REAL_CST
481 && REAL_VALUES_EQUAL (TREE_REAL_CST (exp
), dconsthalf
))
483 tree newfn
= mathfn_built_in (TREE_TYPE (base
), BUILT_IN_SQRT
);
484 tree newarglist
= build_tree_list (NULL_TREE
, base
);
485 return build_function_call_expr (newfn
, newarglist
);
492 /* Function vect_recog_widen_sum_pattern
494 Try to find the following pattern:
497 TYPE x_T, sum = init;
499 sum_0 = phi <init, sum_1>
502 S3 sum_1 = x_T + sum_0;
504 where type 'TYPE' is at least double the size of type 'type', i.e - we're
505 summing elements of type 'type' into an accumulator of type 'TYPE'. This is
506 a special case of a reduction computation.
510 * LAST_STMT: A stmt from which the pattern search begins. In the example,
511 when this function is called with S3, the pattern {S2,S3} will be detected.
515 * TYPE_IN: The type of the input arguments to the pattern.
517 * TYPE_OUT: The type of the output of this pattern.
519 * Return value: A new stmt that will be used to replace the sequence of
520 stmts that constitute the pattern. In this case it will be:
521 WIDEN_SUM <x_t, sum_0>
525 vect_recog_widen_sum_pattern (tree last_stmt
, tree
*type_in
, tree
*type_out
)
529 stmt_vec_info stmt_vinfo
= vinfo_for_stmt (last_stmt
);
530 tree type
, half_type
;
533 if (TREE_CODE (last_stmt
) != MODIFY_EXPR
)
536 expr
= TREE_OPERAND (last_stmt
, 1);
537 type
= TREE_TYPE (expr
);
539 /* Look for the following pattern
542 In which DX is at least double the size of X, and sum_1 has been
543 recognized as a reduction variable.
546 /* Starting from LAST_STMT, follow the defs of its uses in search
547 of the above pattern. */
549 if (TREE_CODE (expr
) != PLUS_EXPR
)
552 if (STMT_VINFO_DEF_TYPE (stmt_vinfo
) != vect_reduction_def
)
555 oprnd0
= TREE_OPERAND (expr
, 0);
556 oprnd1
= TREE_OPERAND (expr
, 1);
557 if (TYPE_MAIN_VARIANT (TREE_TYPE (oprnd0
)) != TYPE_MAIN_VARIANT (type
)
558 || TYPE_MAIN_VARIANT (TREE_TYPE (oprnd1
)) != TYPE_MAIN_VARIANT (type
))
561 /* So far so good. Since last_stmt was detected as a (summation) reduction,
562 we know that oprnd1 is the reduction variable (defined by a loop-header
563 phi), and oprnd0 is an ssa-name defined by a stmt in the loop body.
564 Left to check that oprnd0 is defined by a cast from type 'type' to type
567 if (!widened_name_p (oprnd0
, last_stmt
, &half_type
, &stmt
))
570 oprnd0
= TREE_OPERAND (TREE_OPERAND (stmt
, 1), 0);
571 *type_in
= half_type
;
574 /* Pattern detected. Create a stmt to be used to replace the pattern: */
575 pattern_expr
= build2 (WIDEN_SUM_EXPR
, type
, oprnd0
, oprnd1
);
576 if (vect_print_dump_info (REPORT_DETAILS
))
578 fprintf (vect_dump
, "vect_recog_widen_sum_pattern: detected: ");
579 print_generic_expr (vect_dump
, pattern_expr
, TDF_SLIM
);
585 /* Function vect_pattern_recog_1
588 PATTERN_RECOG_FUNC: A pointer to a function that detects a certain
590 STMT: A stmt from which the pattern search should start.
592 If PATTERN_RECOG_FUNC successfully detected the pattern, it creates an
593 expression that computes the same functionality and can be used to
594 replace the sequence of stmts that are involved in the pattern.
597 This function checks if the expression returned by PATTERN_RECOG_FUNC is
598 supported in vector form by the target. We use 'TYPE_IN' to obtain the
599 relevant vector type. If 'TYPE_IN' is already a vector type, then this
600 indicates that target support had already been checked by PATTERN_RECOG_FUNC.
601 If 'TYPE_OUT' is also returned by PATTERN_RECOG_FUNC, we check that it fits
602 to the available target pattern.
604 This function also does some bookkeeping, as explained in the documentation
605 for vect_recog_pattern. */
608 vect_pattern_recog_1 (
609 tree (* vect_recog_func
) (tree
, tree
*, tree
*),
610 block_stmt_iterator si
)
612 tree stmt
= bsi_stmt (si
);
613 stmt_vec_info stmt_info
= vinfo_for_stmt (stmt
);
614 stmt_vec_info pattern_stmt_info
;
615 loop_vec_info loop_vinfo
= STMT_VINFO_LOOP_VINFO (stmt_info
);
617 tree pattern_vectype
;
618 tree type_in
, type_out
;
624 pattern_expr
= (* vect_recog_func
) (stmt
, &type_in
, &type_out
);
628 if (VECTOR_MODE_P (TYPE_MODE (type_in
)))
630 /* No need to check target support (already checked by the pattern
631 recognition function). */
632 pattern_vectype
= type_in
;
636 enum tree_code vec_mode
;
637 enum insn_code icode
;
640 /* Check target support */
641 pattern_vectype
= get_vectype_for_scalar_type (type_in
);
642 optab
= optab_for_tree_code (TREE_CODE (pattern_expr
), pattern_vectype
);
643 vec_mode
= TYPE_MODE (pattern_vectype
);
645 || (icode
= optab
->handlers
[(int) vec_mode
].insn_code
) ==
648 && (insn_data
[icode
].operand
[0].mode
!=
649 TYPE_MODE (get_vectype_for_scalar_type (type_out
)))))
653 /* Found a vectorizable pattern. */
654 if (vect_print_dump_info (REPORT_DETAILS
))
656 fprintf (vect_dump
, "pattern recognized: ");
657 print_generic_expr (vect_dump
, pattern_expr
, TDF_SLIM
);
660 /* Mark the stmts that are involved in the pattern,
661 create a new stmt to express the pattern and insert it. */
662 code
= TREE_CODE (pattern_expr
);
663 pattern_type
= TREE_TYPE (pattern_expr
);
664 var
= create_tmp_var (pattern_type
, "patt");
665 add_referenced_var (var
);
666 var_name
= make_ssa_name (var
, NULL_TREE
);
667 pattern_expr
= build2 (MODIFY_EXPR
, void_type_node
, var_name
, pattern_expr
);
668 SSA_NAME_DEF_STMT (var_name
) = pattern_expr
;
669 bsi_insert_before (&si
, pattern_expr
, BSI_SAME_STMT
);
670 ann
= stmt_ann (pattern_expr
);
671 set_stmt_info (ann
, new_stmt_vec_info (pattern_expr
, loop_vinfo
));
672 pattern_stmt_info
= vinfo_for_stmt (pattern_expr
);
674 STMT_VINFO_RELATED_STMT (pattern_stmt_info
) = stmt
;
675 STMT_VINFO_DEF_TYPE (pattern_stmt_info
) = STMT_VINFO_DEF_TYPE (stmt_info
);
676 STMT_VINFO_VECTYPE (pattern_stmt_info
) = pattern_vectype
;
677 STMT_VINFO_IN_PATTERN_P (stmt_info
) = true;
678 STMT_VINFO_RELATED_STMT (stmt_info
) = pattern_expr
;
684 /* Function vect_pattern_recog
687 LOOP_VINFO - a struct_loop_info of a loop in which we want to look for
690 Output - for each computation idiom that is detected we insert a new stmt
691 that provides the same functionality and that can be vectorized. We
692 also record some information in the struct_stmt_info of the relevant
693 stmts, as explained below:
695 At the entry to this function we have the following stmts, with the
696 following initial value in the STMT_VINFO fields:
698 stmt in_pattern_p related_stmt vec_stmt
700 S2: a_2 = ..use(a_i).. - - -
701 S3: a_1 = ..use(a_2).. - - -
702 S4: a_0 = ..use(a_1).. - - -
703 S5: ... = ..use(a_0).. - - -
705 Say the sequence {S1,S2,S3,S4} was detected as a pattern that can be
706 represented by a single stmt. We then:
707 - create a new stmt S6 that will replace the pattern.
708 - insert the new stmt S6 before the last stmt in the pattern
709 - fill in the STMT_VINFO fields as follows:
711 in_pattern_p related_stmt vec_stmt
713 S2: a_2 = ..use(a_i).. - - -
714 S3: a_1 = ..use(a_2).. - - -
715 > S6: a_new = .... - S4 -
716 S4: a_0 = ..use(a_1).. true S6 -
717 S5: ... = ..use(a_0).. - - -
719 (the last stmt in the pattern (S4) and the new pattern stmt (S6) point
720 to each other through the RELATED_STMT field).
722 S6 will be marked as relevant in vect_mark_stmts_to_be_vectorized instead
723 of S4 because it will replace all its uses. Stmts {S1,S2,S3} will
724 remain irrelevant unless used by stmts other than S4.
726 If vectorization succeeds, vect_transform_stmt will skip over {S1,S2,S3}
727 (because they are marked as irrelevant). It will vectorize S6, and record
728 a pointer to the new vector stmt VS6 both from S6 (as usual), and also
729 from S4. We do that so that when we get to vectorizing stmts that use the
730 def of S4 (like S5 that uses a_0), we'll know where to take the relevant
731 vector-def from. S4 will be skipped, and S5 will be vectorized as usual:
733 in_pattern_p related_stmt vec_stmt
735 S2: a_2 = ..use(a_i).. - - -
736 S3: a_1 = ..use(a_2).. - - -
737 > VS6: va_new = .... - - -
738 S6: a_new = .... - S4 VS6
739 S4: a_0 = ..use(a_1).. true S6 VS6
740 > VS5: ... = ..vuse(va_new).. - - -
741 S5: ... = ..use(a_0).. - - -
743 DCE could then get rid of {S1,S2,S3,S4,S5,S6} (if their defs are not used
744 elsewhere), and we'll end up with:
747 VS5: ... = ..vuse(va_new)..
749 If vectorization does not succeed, DCE will clean S6 away (its def is
750 not used), and we'll end up with the original sequence.
754 vect_pattern_recog (loop_vec_info loop_vinfo
)
756 struct loop
*loop
= LOOP_VINFO_LOOP (loop_vinfo
);
757 basic_block
*bbs
= LOOP_VINFO_BBS (loop_vinfo
);
758 unsigned int nbbs
= loop
->num_nodes
;
759 block_stmt_iterator si
;
762 tree (* vect_recog_func_ptr
) (tree
, tree
*, tree
*);
764 if (vect_print_dump_info (REPORT_DETAILS
))
765 fprintf (vect_dump
, "=== vect_pattern_recog ===");
767 /* Scan through the loop stmts, applying the pattern recognition
768 functions starting at each stmt visited: */
769 for (i
= 0; i
< nbbs
; i
++)
771 basic_block bb
= bbs
[i
];
772 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
774 stmt
= bsi_stmt (si
);
776 /* Scan over all generic vect_recog_xxx_pattern functions. */
777 for (j
= 0; j
< NUM_PATTERNS
; j
++)
779 vect_recog_func_ptr
= vect_vect_recog_func_ptrs
[j
];
780 vect_pattern_recog_1 (vect_recog_func_ptr
, si
);