1 /* Induction variable optimizations.
2 Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
21 /* This pass tries to find the optimal set of induction variables for the loop.
22 It optimizes just the basic linear induction variables (although adding
23 support for other types should not be too hard). It includes the
24 optimizations commonly known as strength reduction, induction variable
25 coalescing and induction variable elimination. It does it in the
28 1) The interesting uses of induction variables are found. This includes
30 -- uses of induction variables in non-linear expressions
31 -- addresses of arrays
32 -- comparisons of induction variables
34 2) Candidates for the induction variables are found. This includes
36 -- old induction variables
37 -- the variables defined by expressions derived from the "interesting
40 3) The optimal (w.r. to a cost function) set of variables is chosen. The
41 cost function assigns a cost to sets of induction variables and consists
44 -- The use costs. Each of the interesting uses chooses the best induction
45 variable in the set and adds its cost to the sum. The cost reflects
46 the time spent on modifying the induction variables value to be usable
47 for the given purpose (adding base and offset for arrays, etc.).
48 -- The variable costs. Each of the variables has a cost assigned that
49 reflects the costs associated with incrementing the value of the
50 variable. The original variables are somewhat preferred.
51 -- The set cost. Depending on the size of the set, extra cost may be
52 added to reflect register pressure.
54 All the costs are defined in a machine-specific way, using the target
55 hooks and machine descriptions to determine them.
57 4) The trees are transformed to use the new variables, the dead code is
60 All of this is done loop by loop. Doing it globally is theoretically
61 possible, it might give a better performance and it might enable us
62 to decide costs more precisely, but getting all the interactions right
63 would be complicated. */
67 #include "coretypes.h"
72 #include "hard-reg-set.h"
73 #include "basic-block.h"
75 #include "diagnostic.h"
76 #include "tree-flow.h"
77 #include "tree-dump.h"
82 #include "tree-pass.h"
84 #include "insn-config.h"
87 #include "tree-chrec.h"
88 #include "tree-scalar-evolution.h"
91 #include "langhooks.h"
93 /* The infinite cost. */
94 #define INFTY 10000000
96 /* The expected number of loop iterations. TODO -- use profiling instead of
98 #define AVG_LOOP_NITER(LOOP) 5
101 /* Representation of the induction variable. */
104 tree base
; /* Initial value of the iv. */
105 tree base_object
; /* A memory object to that the induction variable points. */
106 tree step
; /* Step of the iv (constant only). */
107 tree ssa_name
; /* The ssa name with the value. */
108 bool biv_p
; /* Is it a biv? */
109 bool have_use_for
; /* Do we already have a use for it? */
110 unsigned use_id
; /* The identifier in the use if it is the case. */
113 /* Per-ssa version information (induction variable descriptions, etc.). */
116 tree name
; /* The ssa name. */
117 struct iv
*iv
; /* Induction variable description. */
118 bool has_nonlin_use
; /* For a loop-level invariant, whether it is used in
119 an expression that is not an induction variable. */
120 unsigned inv_id
; /* Id of an invariant. */
121 bool preserve_biv
; /* For the original biv, whether to preserve it. */
124 /* Information attached to loop. */
127 unsigned regs_used
; /* Number of registers used. */
133 USE_NONLINEAR_EXPR
, /* Use in a nonlinear expression. */
134 USE_OUTER
, /* The induction variable is used outside the loop. */
135 USE_ADDRESS
, /* Use in an address. */
136 USE_COMPARE
/* Use is a compare. */
139 /* The candidate - cost pair. */
142 struct iv_cand
*cand
; /* The candidate. */
143 unsigned cost
; /* The cost. */
144 bitmap depends_on
; /* The list of invariants that have to be
146 tree value
; /* For final value elimination, the expression for
147 the final value of the iv. For iv elimination,
148 the new bound to compare with. */
154 unsigned id
; /* The id of the use. */
155 enum use_type type
; /* Type of the use. */
156 struct iv
*iv
; /* The induction variable it is based on. */
157 tree stmt
; /* Statement in that it occurs. */
158 tree
*op_p
; /* The place where it occurs. */
159 bitmap related_cands
; /* The set of "related" iv candidates, plus the common
162 unsigned n_map_members
; /* Number of candidates in the cost_map list. */
163 struct cost_pair
*cost_map
;
164 /* The costs wrto the iv candidates. */
166 struct iv_cand
*selected
;
167 /* The selected candidate. */
170 /* The position where the iv is computed. */
173 IP_NORMAL
, /* At the end, just before the exit condition. */
174 IP_END
, /* At the end of the latch block. */
175 IP_ORIGINAL
/* The original biv. */
178 /* The induction variable candidate. */
181 unsigned id
; /* The number of the candidate. */
182 bool important
; /* Whether this is an "important" candidate, i.e. such
183 that it should be considered by all uses. */
184 enum iv_position pos
; /* Where it is computed. */
185 tree incremented_at
; /* For original biv, the statement where it is
187 tree var_before
; /* The variable used for it before increment. */
188 tree var_after
; /* The variable used for it after increment. */
189 struct iv
*iv
; /* The value of the candidate. NULL for
190 "pseudocandidate" used to indicate the possibility
191 to replace the final value of an iv by direct
192 computation of the value. */
193 unsigned cost
; /* Cost of the candidate. */
194 bitmap depends_on
; /* The list of invariants that are used in step of the
198 /* The data used by the induction variable optimizations. */
200 typedef struct iv_use
*iv_use_p
;
202 DEF_VEC_ALLOC_P(iv_use_p
,heap
);
204 typedef struct iv_cand
*iv_cand_p
;
205 DEF_VEC_P(iv_cand_p
);
206 DEF_VEC_ALLOC_P(iv_cand_p
,heap
);
210 /* The currently optimized loop. */
211 struct loop
*current_loop
;
213 /* Numbers of iterations for all exits of the current loop. */
216 /* The size of version_info array allocated. */
217 unsigned version_info_size
;
219 /* The array of information for the ssa names. */
220 struct version_info
*version_info
;
222 /* The bitmap of indices in version_info whose value was changed. */
225 /* The maximum invariant id. */
228 /* The uses of induction variables. */
229 VEC(iv_use_p
,heap
) *iv_uses
;
231 /* The candidates. */
232 VEC(iv_cand_p
,heap
) *iv_candidates
;
234 /* A bitmap of important candidates. */
235 bitmap important_candidates
;
237 /* Whether to consider just related and important candidates when replacing a
239 bool consider_all_candidates
;
242 /* An assignment of iv candidates to uses. */
246 /* The number of uses covered by the assignment. */
249 /* Number of uses that cannot be expressed by the candidates in the set. */
252 /* Candidate assigned to a use, together with the related costs. */
253 struct cost_pair
**cand_for_use
;
255 /* Number of times each candidate is used. */
256 unsigned *n_cand_uses
;
258 /* The candidates used. */
261 /* The number of candidates in the set. */
264 /* Total number of registers needed. */
267 /* Total cost of expressing uses. */
268 unsigned cand_use_cost
;
270 /* Total cost of candidates. */
273 /* Number of times each invariant is used. */
274 unsigned *n_invariant_uses
;
276 /* Total cost of the assignment. */
280 /* Difference of two iv candidate assignments. */
287 /* An old assignment (for rollback purposes). */
288 struct cost_pair
*old_cp
;
290 /* A new assignment. */
291 struct cost_pair
*new_cp
;
293 /* Next change in the list. */
294 struct iv_ca_delta
*next_change
;
297 /* Bound on number of candidates below that all candidates are considered. */
299 #define CONSIDER_ALL_CANDIDATES_BOUND \
300 ((unsigned) PARAM_VALUE (PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND))
302 /* If there are more iv occurrences, we just give up (it is quite unlikely that
303 optimizing such a loop would help, and it would take ages). */
305 #define MAX_CONSIDERED_USES \
306 ((unsigned) PARAM_VALUE (PARAM_IV_MAX_CONSIDERED_USES))
308 /* If there are at most this number of ivs in the set, try removing unnecessary
309 ivs from the set always. */
311 #define ALWAYS_PRUNE_CAND_SET_BOUND \
312 ((unsigned) PARAM_VALUE (PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND))
314 /* The list of trees for that the decl_rtl field must be reset is stored
317 static VEC(tree
,heap
) *decl_rtl_to_reset
;
319 /* Number of uses recorded in DATA. */
321 static inline unsigned
322 n_iv_uses (struct ivopts_data
*data
)
324 return VEC_length (iv_use_p
, data
->iv_uses
);
327 /* Ith use recorded in DATA. */
329 static inline struct iv_use
*
330 iv_use (struct ivopts_data
*data
, unsigned i
)
332 return VEC_index (iv_use_p
, data
->iv_uses
, i
);
335 /* Number of candidates recorded in DATA. */
337 static inline unsigned
338 n_iv_cands (struct ivopts_data
*data
)
340 return VEC_length (iv_cand_p
, data
->iv_candidates
);
343 /* Ith candidate recorded in DATA. */
345 static inline struct iv_cand
*
346 iv_cand (struct ivopts_data
*data
, unsigned i
)
348 return VEC_index (iv_cand_p
, data
->iv_candidates
, i
);
351 /* The data for LOOP. */
353 static inline struct loop_data
*
354 loop_data (struct loop
*loop
)
359 /* The single loop exit if it dominates the latch, NULL otherwise. */
362 single_dom_exit (struct loop
*loop
)
364 edge exit
= loop
->single_exit
;
369 if (!just_once_each_iteration_p (loop
, exit
->src
))
375 /* Dumps information about the induction variable IV to FILE. */
377 extern void dump_iv (FILE *, struct iv
*);
379 dump_iv (FILE *file
, struct iv
*iv
)
383 fprintf (file
, "ssa name ");
384 print_generic_expr (file
, iv
->ssa_name
, TDF_SLIM
);
385 fprintf (file
, "\n");
388 fprintf (file
, " type ");
389 print_generic_expr (file
, TREE_TYPE (iv
->base
), TDF_SLIM
);
390 fprintf (file
, "\n");
394 fprintf (file
, " base ");
395 print_generic_expr (file
, iv
->base
, TDF_SLIM
);
396 fprintf (file
, "\n");
398 fprintf (file
, " step ");
399 print_generic_expr (file
, iv
->step
, TDF_SLIM
);
400 fprintf (file
, "\n");
404 fprintf (file
, " invariant ");
405 print_generic_expr (file
, iv
->base
, TDF_SLIM
);
406 fprintf (file
, "\n");
411 fprintf (file
, " base object ");
412 print_generic_expr (file
, iv
->base_object
, TDF_SLIM
);
413 fprintf (file
, "\n");
417 fprintf (file
, " is a biv\n");
420 /* Dumps information about the USE to FILE. */
422 extern void dump_use (FILE *, struct iv_use
*);
424 dump_use (FILE *file
, struct iv_use
*use
)
426 fprintf (file
, "use %d\n", use
->id
);
430 case USE_NONLINEAR_EXPR
:
431 fprintf (file
, " generic\n");
435 fprintf (file
, " outside\n");
439 fprintf (file
, " address\n");
443 fprintf (file
, " compare\n");
450 fprintf (file
, " in statement ");
451 print_generic_expr (file
, use
->stmt
, TDF_SLIM
);
452 fprintf (file
, "\n");
454 fprintf (file
, " at position ");
456 print_generic_expr (file
, *use
->op_p
, TDF_SLIM
);
457 fprintf (file
, "\n");
459 dump_iv (file
, use
->iv
);
461 if (use
->related_cands
)
463 fprintf (file
, " related candidates ");
464 dump_bitmap (file
, use
->related_cands
);
468 /* Dumps information about the uses to FILE. */
470 extern void dump_uses (FILE *, struct ivopts_data
*);
472 dump_uses (FILE *file
, struct ivopts_data
*data
)
477 for (i
= 0; i
< n_iv_uses (data
); i
++)
479 use
= iv_use (data
, i
);
481 dump_use (file
, use
);
482 fprintf (file
, "\n");
486 /* Dumps information about induction variable candidate CAND to FILE. */
488 extern void dump_cand (FILE *, struct iv_cand
*);
490 dump_cand (FILE *file
, struct iv_cand
*cand
)
492 struct iv
*iv
= cand
->iv
;
494 fprintf (file
, "candidate %d%s\n",
495 cand
->id
, cand
->important
? " (important)" : "");
497 if (cand
->depends_on
)
499 fprintf (file
, " depends on ");
500 dump_bitmap (file
, cand
->depends_on
);
505 fprintf (file
, " final value replacement\n");
512 fprintf (file
, " incremented before exit test\n");
516 fprintf (file
, " incremented at end\n");
520 fprintf (file
, " original biv\n");
527 /* Returns the info for ssa version VER. */
529 static inline struct version_info
*
530 ver_info (struct ivopts_data
*data
, unsigned ver
)
532 return data
->version_info
+ ver
;
535 /* Returns the info for ssa name NAME. */
537 static inline struct version_info
*
538 name_info (struct ivopts_data
*data
, tree name
)
540 return ver_info (data
, SSA_NAME_VERSION (name
));
543 /* Checks whether there exists number X such that X * B = A, counting modulo
547 divide (unsigned bits
, unsigned HOST_WIDE_INT a
, unsigned HOST_WIDE_INT b
,
550 unsigned HOST_WIDE_INT mask
= ~(~(unsigned HOST_WIDE_INT
) 0 << (bits
- 1) << 1);
551 unsigned HOST_WIDE_INT inv
, ex
, val
;
557 /* First divide the whole equation by 2 as long as possible. */
558 while (!(a
& 1) && !(b
& 1))
568 /* If b is still even, a is odd and there is no such x. */
572 /* Find the inverse of b. We compute it as
573 b^(2^(bits - 1) - 1) (mod 2^bits). */
576 for (i
= 0; i
< bits
- 1; i
++)
578 inv
= (inv
* ex
) & mask
;
579 ex
= (ex
* ex
) & mask
;
582 val
= (a
* inv
) & mask
;
584 gcc_assert (((val
* b
) & mask
) == a
);
586 if ((val
>> (bits
- 1)) & 1)
594 /* Returns true if STMT is after the place where the IP_NORMAL ivs will be
598 stmt_after_ip_normal_pos (struct loop
*loop
, tree stmt
)
600 basic_block bb
= ip_normal_pos (loop
), sbb
= bb_for_stmt (stmt
);
604 if (sbb
== loop
->latch
)
610 return stmt
== last_stmt (bb
);
613 /* Returns true if STMT if after the place where the original induction
614 variable CAND is incremented. */
617 stmt_after_ip_original_pos (struct iv_cand
*cand
, tree stmt
)
619 basic_block cand_bb
= bb_for_stmt (cand
->incremented_at
);
620 basic_block stmt_bb
= bb_for_stmt (stmt
);
621 block_stmt_iterator bsi
;
623 if (!dominated_by_p (CDI_DOMINATORS
, stmt_bb
, cand_bb
))
626 if (stmt_bb
!= cand_bb
)
629 /* Scan the block from the end, since the original ivs are usually
630 incremented at the end of the loop body. */
631 for (bsi
= bsi_last (stmt_bb
); ; bsi_prev (&bsi
))
633 if (bsi_stmt (bsi
) == cand
->incremented_at
)
635 if (bsi_stmt (bsi
) == stmt
)
640 /* Returns true if STMT if after the place where the induction variable
641 CAND is incremented in LOOP. */
644 stmt_after_increment (struct loop
*loop
, struct iv_cand
*cand
, tree stmt
)
652 return stmt_after_ip_normal_pos (loop
, stmt
);
655 return stmt_after_ip_original_pos (cand
, stmt
);
662 /* Element of the table in that we cache the numbers of iterations obtained
663 from exits of the loop. */
667 /* The edge for that the number of iterations is cached. */
670 /* True if the # of iterations was successfully determined. */
673 /* Description of # of iterations. */
674 struct tree_niter_desc niter
;
677 /* Hash function for nfe_cache_elt E. */
680 nfe_hash (const void *e
)
682 const struct nfe_cache_elt
*elt
= e
;
684 return htab_hash_pointer (elt
->exit
);
687 /* Equality function for nfe_cache_elt E1 and edge E2. */
690 nfe_eq (const void *e1
, const void *e2
)
692 const struct nfe_cache_elt
*elt1
= e1
;
694 return elt1
->exit
== e2
;
697 /* Returns structure describing number of iterations determined from
698 EXIT of DATA->current_loop, or NULL if something goes wrong. */
700 static struct tree_niter_desc
*
701 niter_for_exit (struct ivopts_data
*data
, edge exit
)
703 struct nfe_cache_elt
*nfe_desc
;
706 slot
= htab_find_slot_with_hash (data
->niters
, exit
,
707 htab_hash_pointer (exit
),
712 nfe_desc
= xmalloc (sizeof (struct nfe_cache_elt
));
713 nfe_desc
->exit
= exit
;
714 nfe_desc
->valid_p
= number_of_iterations_exit (data
->current_loop
,
715 exit
, &nfe_desc
->niter
);
721 if (!nfe_desc
->valid_p
)
724 return &nfe_desc
->niter
;
727 /* Returns structure describing number of iterations determined from
728 single dominating exit of DATA->current_loop, or NULL if something
731 static struct tree_niter_desc
*
732 niter_for_single_dom_exit (struct ivopts_data
*data
)
734 edge exit
= single_dom_exit (data
->current_loop
);
739 return niter_for_exit (data
, exit
);
742 /* Initializes data structures used by the iv optimization pass, stored
743 in DATA. LOOPS is the loop tree. */
746 tree_ssa_iv_optimize_init (struct loops
*loops
, struct ivopts_data
*data
)
750 data
->version_info_size
= 2 * num_ssa_names
;
751 data
->version_info
= xcalloc (data
->version_info_size
,
752 sizeof (struct version_info
));
753 data
->relevant
= BITMAP_ALLOC (NULL
);
754 data
->important_candidates
= BITMAP_ALLOC (NULL
);
755 data
->max_inv_id
= 0;
756 data
->niters
= htab_create (10, nfe_hash
, nfe_eq
, free
);
758 for (i
= 1; i
< loops
->num
; i
++)
759 if (loops
->parray
[i
])
760 loops
->parray
[i
]->aux
= xcalloc (1, sizeof (struct loop_data
));
762 data
->iv_uses
= VEC_alloc (iv_use_p
, heap
, 20);
763 data
->iv_candidates
= VEC_alloc (iv_cand_p
, heap
, 20);
764 decl_rtl_to_reset
= VEC_alloc (tree
, heap
, 20);
767 /* Returns a memory object to that EXPR points. In case we are able to
768 determine that it does not point to any such object, NULL is returned. */
771 determine_base_object (tree expr
)
773 enum tree_code code
= TREE_CODE (expr
);
774 tree base
, obj
, op0
, op1
;
776 if (!POINTER_TYPE_P (TREE_TYPE (expr
)))
785 obj
= TREE_OPERAND (expr
, 0);
786 base
= get_base_address (obj
);
791 if (TREE_CODE (base
) == INDIRECT_REF
)
792 return determine_base_object (TREE_OPERAND (base
, 0));
794 return fold_convert (ptr_type_node
,
795 build_fold_addr_expr (base
));
799 op0
= determine_base_object (TREE_OPERAND (expr
, 0));
800 op1
= determine_base_object (TREE_OPERAND (expr
, 1));
806 return (code
== PLUS_EXPR
808 : fold_build1 (NEGATE_EXPR
, ptr_type_node
, op1
));
810 return fold_build2 (code
, ptr_type_node
, op0
, op1
);
814 return determine_base_object (TREE_OPERAND (expr
, 0));
817 return fold_convert (ptr_type_node
, expr
);
821 /* Allocates an induction variable with given initial value BASE and step STEP
825 alloc_iv (tree base
, tree step
)
827 struct iv
*iv
= xcalloc (1, sizeof (struct iv
));
829 if (step
&& integer_zerop (step
))
833 iv
->base_object
= determine_base_object (base
);
836 iv
->have_use_for
= false;
838 iv
->ssa_name
= NULL_TREE
;
843 /* Sets STEP and BASE for induction variable IV. */
846 set_iv (struct ivopts_data
*data
, tree iv
, tree base
, tree step
)
848 struct version_info
*info
= name_info (data
, iv
);
850 gcc_assert (!info
->iv
);
852 bitmap_set_bit (data
->relevant
, SSA_NAME_VERSION (iv
));
853 info
->iv
= alloc_iv (base
, step
);
854 info
->iv
->ssa_name
= iv
;
857 /* Finds induction variable declaration for VAR. */
860 get_iv (struct ivopts_data
*data
, tree var
)
864 if (!name_info (data
, var
)->iv
)
866 bb
= bb_for_stmt (SSA_NAME_DEF_STMT (var
));
869 || !flow_bb_inside_loop_p (data
->current_loop
, bb
))
870 set_iv (data
, var
, var
, NULL_TREE
);
873 return name_info (data
, var
)->iv
;
876 /* Determines the step of a biv defined in PHI. Returns NULL if PHI does
877 not define a simple affine biv with nonzero step. */
880 determine_biv_step (tree phi
)
882 struct loop
*loop
= bb_for_stmt (phi
)->loop_father
;
883 tree name
= PHI_RESULT (phi
), base
, step
;
885 if (!is_gimple_reg (name
))
888 if (!simple_iv (loop
, phi
, name
, &base
, &step
, true))
897 /* Returns true if EXP is a ssa name that occurs in an abnormal phi node. */
900 abnormal_ssa_name_p (tree exp
)
905 if (TREE_CODE (exp
) != SSA_NAME
)
908 return SSA_NAME_OCCURS_IN_ABNORMAL_PHI (exp
) != 0;
911 /* Returns false if BASE or INDEX contains a ssa name that occurs in an
912 abnormal phi node. Callback for for_each_index. */
915 idx_contains_abnormal_ssa_name_p (tree base
, tree
*index
,
916 void *data ATTRIBUTE_UNUSED
)
918 if (TREE_CODE (base
) == ARRAY_REF
)
920 if (abnormal_ssa_name_p (TREE_OPERAND (base
, 2)))
922 if (abnormal_ssa_name_p (TREE_OPERAND (base
, 3)))
926 return !abnormal_ssa_name_p (*index
);
929 /* Returns true if EXPR contains a ssa name that occurs in an
930 abnormal phi node. */
933 contains_abnormal_ssa_name_p (tree expr
)
936 enum tree_code_class
class;
941 code
= TREE_CODE (expr
);
942 class = TREE_CODE_CLASS (code
);
944 if (code
== SSA_NAME
)
945 return SSA_NAME_OCCURS_IN_ABNORMAL_PHI (expr
) != 0;
947 if (code
== INTEGER_CST
948 || is_gimple_min_invariant (expr
))
951 if (code
== ADDR_EXPR
)
952 return !for_each_index (&TREE_OPERAND (expr
, 0),
953 idx_contains_abnormal_ssa_name_p
,
960 if (contains_abnormal_ssa_name_p (TREE_OPERAND (expr
, 1)))
965 if (contains_abnormal_ssa_name_p (TREE_OPERAND (expr
, 0)))
977 /* Finds basic ivs. */
980 find_bivs (struct ivopts_data
*data
)
982 tree phi
, step
, type
, base
;
984 struct loop
*loop
= data
->current_loop
;
986 for (phi
= phi_nodes (loop
->header
); phi
; phi
= PHI_CHAIN (phi
))
988 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi
)))
991 step
= determine_biv_step (phi
);
995 base
= PHI_ARG_DEF_FROM_EDGE (phi
, loop_preheader_edge (loop
));
996 base
= expand_simple_operations (base
);
997 if (contains_abnormal_ssa_name_p (base
)
998 || contains_abnormal_ssa_name_p (step
))
1001 type
= TREE_TYPE (PHI_RESULT (phi
));
1002 base
= fold_convert (type
, base
);
1004 step
= fold_convert (type
, step
);
1006 set_iv (data
, PHI_RESULT (phi
), base
, step
);
1013 /* Marks basic ivs. */
1016 mark_bivs (struct ivopts_data
*data
)
1019 struct iv
*iv
, *incr_iv
;
1020 struct loop
*loop
= data
->current_loop
;
1021 basic_block incr_bb
;
1023 for (phi
= phi_nodes (loop
->header
); phi
; phi
= PHI_CHAIN (phi
))
1025 iv
= get_iv (data
, PHI_RESULT (phi
));
1029 var
= PHI_ARG_DEF_FROM_EDGE (phi
, loop_latch_edge (loop
));
1030 incr_iv
= get_iv (data
, var
);
1034 /* If the increment is in the subloop, ignore it. */
1035 incr_bb
= bb_for_stmt (SSA_NAME_DEF_STMT (var
));
1036 if (incr_bb
->loop_father
!= data
->current_loop
1037 || (incr_bb
->flags
& BB_IRREDUCIBLE_LOOP
))
1041 incr_iv
->biv_p
= true;
1045 /* Checks whether STMT defines a linear induction variable and stores its
1046 parameters to BASE and STEP. */
1049 find_givs_in_stmt_scev (struct ivopts_data
*data
, tree stmt
,
1050 tree
*base
, tree
*step
)
1053 struct loop
*loop
= data
->current_loop
;
1058 if (TREE_CODE (stmt
) != MODIFY_EXPR
)
1061 lhs
= TREE_OPERAND (stmt
, 0);
1062 if (TREE_CODE (lhs
) != SSA_NAME
)
1065 if (!simple_iv (loop
, stmt
, TREE_OPERAND (stmt
, 1), base
, step
, true))
1067 *base
= expand_simple_operations (*base
);
1069 if (contains_abnormal_ssa_name_p (*base
)
1070 || contains_abnormal_ssa_name_p (*step
))
1076 /* Finds general ivs in statement STMT. */
1079 find_givs_in_stmt (struct ivopts_data
*data
, tree stmt
)
1083 if (!find_givs_in_stmt_scev (data
, stmt
, &base
, &step
))
1086 set_iv (data
, TREE_OPERAND (stmt
, 0), base
, step
);
1089 /* Finds general ivs in basic block BB. */
1092 find_givs_in_bb (struct ivopts_data
*data
, basic_block bb
)
1094 block_stmt_iterator bsi
;
1096 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1097 find_givs_in_stmt (data
, bsi_stmt (bsi
));
1100 /* Finds general ivs. */
1103 find_givs (struct ivopts_data
*data
)
1105 struct loop
*loop
= data
->current_loop
;
1106 basic_block
*body
= get_loop_body_in_dom_order (loop
);
1109 for (i
= 0; i
< loop
->num_nodes
; i
++)
1110 find_givs_in_bb (data
, body
[i
]);
1114 /* For each ssa name defined in LOOP determines whether it is an induction
1115 variable and if so, its initial value and step. */
1118 find_induction_variables (struct ivopts_data
*data
)
1123 if (!find_bivs (data
))
1129 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1131 struct tree_niter_desc
*niter
;
1133 niter
= niter_for_single_dom_exit (data
);
1137 fprintf (dump_file
, " number of iterations ");
1138 print_generic_expr (dump_file
, niter
->niter
, TDF_SLIM
);
1139 fprintf (dump_file
, "\n");
1141 fprintf (dump_file
, " may be zero if ");
1142 print_generic_expr (dump_file
, niter
->may_be_zero
, TDF_SLIM
);
1143 fprintf (dump_file
, "\n");
1144 fprintf (dump_file
, "\n");
1147 fprintf (dump_file
, "Induction variables:\n\n");
1149 EXECUTE_IF_SET_IN_BITMAP (data
->relevant
, 0, i
, bi
)
1151 if (ver_info (data
, i
)->iv
)
1152 dump_iv (dump_file
, ver_info (data
, i
)->iv
);
1159 /* Records a use of type USE_TYPE at *USE_P in STMT whose value is IV. */
1161 static struct iv_use
*
1162 record_use (struct ivopts_data
*data
, tree
*use_p
, struct iv
*iv
,
1163 tree stmt
, enum use_type use_type
)
1165 struct iv_use
*use
= xcalloc (1, sizeof (struct iv_use
));
1167 use
->id
= n_iv_uses (data
);
1168 use
->type
= use_type
;
1172 use
->related_cands
= BITMAP_ALLOC (NULL
);
1174 /* To avoid showing ssa name in the dumps, if it was not reset by the
1176 iv
->ssa_name
= NULL_TREE
;
1178 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1179 dump_use (dump_file
, use
);
1181 VEC_safe_push (iv_use_p
, heap
, data
->iv_uses
, use
);
1186 /* Checks whether OP is a loop-level invariant and if so, records it.
1187 NONLINEAR_USE is true if the invariant is used in a way we do not
1188 handle specially. */
1191 record_invariant (struct ivopts_data
*data
, tree op
, bool nonlinear_use
)
1194 struct version_info
*info
;
1196 if (TREE_CODE (op
) != SSA_NAME
1197 || !is_gimple_reg (op
))
1200 bb
= bb_for_stmt (SSA_NAME_DEF_STMT (op
));
1202 && flow_bb_inside_loop_p (data
->current_loop
, bb
))
1205 info
= name_info (data
, op
);
1207 info
->has_nonlin_use
|= nonlinear_use
;
1209 info
->inv_id
= ++data
->max_inv_id
;
1210 bitmap_set_bit (data
->relevant
, SSA_NAME_VERSION (op
));
1213 /* Checks whether the use OP is interesting and if so, records it
1216 static struct iv_use
*
1217 find_interesting_uses_outer_or_nonlin (struct ivopts_data
*data
, tree op
,
1225 if (TREE_CODE (op
) != SSA_NAME
)
1228 iv
= get_iv (data
, op
);
1232 if (iv
->have_use_for
)
1234 use
= iv_use (data
, iv
->use_id
);
1236 gcc_assert (use
->type
== USE_NONLINEAR_EXPR
1237 || use
->type
== USE_OUTER
);
1239 if (type
== USE_NONLINEAR_EXPR
)
1240 use
->type
= USE_NONLINEAR_EXPR
;
1244 if (zero_p (iv
->step
))
1246 record_invariant (data
, op
, true);
1249 iv
->have_use_for
= true;
1251 civ
= xmalloc (sizeof (struct iv
));
1254 stmt
= SSA_NAME_DEF_STMT (op
);
1255 gcc_assert (TREE_CODE (stmt
) == PHI_NODE
1256 || TREE_CODE (stmt
) == MODIFY_EXPR
);
1258 use
= record_use (data
, NULL
, civ
, stmt
, type
);
1259 iv
->use_id
= use
->id
;
1264 /* Checks whether the use OP is interesting and if so, records it. */
1266 static struct iv_use
*
1267 find_interesting_uses_op (struct ivopts_data
*data
, tree op
)
1269 return find_interesting_uses_outer_or_nonlin (data
, op
, USE_NONLINEAR_EXPR
);
1272 /* Records a definition of induction variable OP that is used outside of the
1275 static struct iv_use
*
1276 find_interesting_uses_outer (struct ivopts_data
*data
, tree op
)
1278 return find_interesting_uses_outer_or_nonlin (data
, op
, USE_OUTER
);
1281 /* Checks whether the condition *COND_P in STMT is interesting
1282 and if so, records it. */
1285 find_interesting_uses_cond (struct ivopts_data
*data
, tree stmt
, tree
*cond_p
)
1289 struct iv
*iv0
= NULL
, *iv1
= NULL
, *civ
;
1291 tree zero
= integer_zero_node
;
1293 const_iv
.step
= NULL_TREE
;
1295 if (TREE_CODE (*cond_p
) != SSA_NAME
1296 && !COMPARISON_CLASS_P (*cond_p
))
1299 if (TREE_CODE (*cond_p
) == SSA_NAME
)
1306 op0_p
= &TREE_OPERAND (*cond_p
, 0);
1307 op1_p
= &TREE_OPERAND (*cond_p
, 1);
1310 if (TREE_CODE (*op0_p
) == SSA_NAME
)
1311 iv0
= get_iv (data
, *op0_p
);
1315 if (TREE_CODE (*op1_p
) == SSA_NAME
)
1316 iv1
= get_iv (data
, *op1_p
);
1320 if (/* When comparing with non-invariant value, we may not do any senseful
1321 induction variable elimination. */
1323 /* Eliminating condition based on two ivs would be nontrivial.
1324 ??? TODO -- it is not really important to handle this case. */
1325 || (!zero_p (iv0
->step
) && !zero_p (iv1
->step
)))
1327 find_interesting_uses_op (data
, *op0_p
);
1328 find_interesting_uses_op (data
, *op1_p
);
1332 if (zero_p (iv0
->step
) && zero_p (iv1
->step
))
1334 /* If both are invariants, this is a work for unswitching. */
1338 civ
= xmalloc (sizeof (struct iv
));
1339 *civ
= zero_p (iv0
->step
) ? *iv1
: *iv0
;
1340 record_use (data
, cond_p
, civ
, stmt
, USE_COMPARE
);
1343 /* Returns true if expression EXPR is obviously invariant in LOOP,
1344 i.e. if all its operands are defined outside of the LOOP. */
1347 expr_invariant_in_loop_p (struct loop
*loop
, tree expr
)
1352 if (is_gimple_min_invariant (expr
))
1355 if (TREE_CODE (expr
) == SSA_NAME
)
1357 def_bb
= bb_for_stmt (SSA_NAME_DEF_STMT (expr
));
1359 && flow_bb_inside_loop_p (loop
, def_bb
))
1368 len
= TREE_CODE_LENGTH (TREE_CODE (expr
));
1369 for (i
= 0; i
< len
; i
++)
1370 if (!expr_invariant_in_loop_p (loop
, TREE_OPERAND (expr
, i
)))
1376 /* Cumulates the steps of indices into DATA and replaces their values with the
1377 initial ones. Returns false when the value of the index cannot be determined.
1378 Callback for for_each_index. */
1380 struct ifs_ivopts_data
1382 struct ivopts_data
*ivopts_data
;
1388 idx_find_step (tree base
, tree
*idx
, void *data
)
1390 struct ifs_ivopts_data
*dta
= data
;
1392 tree step
, iv_step
, lbound
, off
;
1393 struct loop
*loop
= dta
->ivopts_data
->current_loop
;
1395 if (TREE_CODE (base
) == MISALIGNED_INDIRECT_REF
1396 || TREE_CODE (base
) == ALIGN_INDIRECT_REF
)
1399 /* If base is a component ref, require that the offset of the reference
1401 if (TREE_CODE (base
) == COMPONENT_REF
)
1403 off
= component_ref_field_offset (base
);
1404 return expr_invariant_in_loop_p (loop
, off
);
1407 /* If base is array, first check whether we will be able to move the
1408 reference out of the loop (in order to take its address in strength
1409 reduction). In order for this to work we need both lower bound
1410 and step to be loop invariants. */
1411 if (TREE_CODE (base
) == ARRAY_REF
)
1413 step
= array_ref_element_size (base
);
1414 lbound
= array_ref_low_bound (base
);
1416 if (!expr_invariant_in_loop_p (loop
, step
)
1417 || !expr_invariant_in_loop_p (loop
, lbound
))
1421 if (TREE_CODE (*idx
) != SSA_NAME
)
1424 iv
= get_iv (dta
->ivopts_data
, *idx
);
1433 if (TREE_CODE (base
) == ARRAY_REF
)
1435 step
= array_ref_element_size (base
);
1437 /* We only handle addresses whose step is an integer constant. */
1438 if (TREE_CODE (step
) != INTEGER_CST
)
1442 /* The step for pointer arithmetics already is 1 byte. */
1443 step
= build_int_cst (sizetype
, 1);
1445 iv_step
= convert_step (dta
->ivopts_data
->current_loop
,
1446 sizetype
, iv
->base
, iv
->step
, dta
->stmt
);
1450 /* The index might wrap. */
1454 step
= fold_build2 (MULT_EXPR
, sizetype
, step
, iv_step
);
1457 *dta
->step_p
= step
;
1459 *dta
->step_p
= fold_build2 (PLUS_EXPR
, sizetype
, *dta
->step_p
, step
);
1464 /* Records use in index IDX. Callback for for_each_index. Ivopts data
1465 object is passed to it in DATA. */
1468 idx_record_use (tree base
, tree
*idx
,
1471 find_interesting_uses_op (data
, *idx
);
1472 if (TREE_CODE (base
) == ARRAY_REF
)
1474 find_interesting_uses_op (data
, array_ref_element_size (base
));
1475 find_interesting_uses_op (data
, array_ref_low_bound (base
));
1480 /* Returns true if memory reference REF may be unaligned. */
1483 may_be_unaligned_p (tree ref
)
1487 HOST_WIDE_INT bitsize
;
1488 HOST_WIDE_INT bitpos
;
1490 enum machine_mode mode
;
1491 int unsignedp
, volatilep
;
1492 unsigned base_align
;
1494 /* TARGET_MEM_REFs are translated directly to valid MEMs on the target,
1495 thus they are not misaligned. */
1496 if (TREE_CODE (ref
) == TARGET_MEM_REF
)
1499 /* The test below is basically copy of what expr.c:normal_inner_ref
1500 does to check whether the object must be loaded by parts when
1501 STRICT_ALIGNMENT is true. */
1502 base
= get_inner_reference (ref
, &bitsize
, &bitpos
, &toffset
, &mode
,
1503 &unsignedp
, &volatilep
, true);
1504 base_type
= TREE_TYPE (base
);
1505 base_align
= TYPE_ALIGN (base_type
);
1508 && (base_align
< GET_MODE_ALIGNMENT (mode
)
1509 || bitpos
% GET_MODE_ALIGNMENT (mode
) != 0
1510 || bitpos
% BITS_PER_UNIT
!= 0))
1516 /* Finds addresses in *OP_P inside STMT. */
1519 find_interesting_uses_address (struct ivopts_data
*data
, tree stmt
, tree
*op_p
)
1521 tree base
= *op_p
, step
= NULL
;
1523 struct ifs_ivopts_data ifs_ivopts_data
;
1525 /* Do not play with volatile memory references. A bit too conservative,
1526 perhaps, but safe. */
1527 if (stmt_ann (stmt
)->has_volatile_ops
)
1530 /* Ignore bitfields for now. Not really something terribly complicated
1532 if (TREE_CODE (base
) == COMPONENT_REF
1533 && DECL_NONADDRESSABLE_P (TREE_OPERAND (base
, 1)))
1536 if (STRICT_ALIGNMENT
1537 && may_be_unaligned_p (base
))
1540 base
= unshare_expr (base
);
1542 if (TREE_CODE (base
) == TARGET_MEM_REF
)
1544 tree type
= build_pointer_type (TREE_TYPE (base
));
1548 && TREE_CODE (TMR_BASE (base
)) == SSA_NAME
)
1550 civ
= get_iv (data
, TMR_BASE (base
));
1554 TMR_BASE (base
) = civ
->base
;
1557 if (TMR_INDEX (base
)
1558 && TREE_CODE (TMR_INDEX (base
)) == SSA_NAME
)
1560 civ
= get_iv (data
, TMR_INDEX (base
));
1564 TMR_INDEX (base
) = civ
->base
;
1569 if (TMR_STEP (base
))
1570 astep
= fold_build2 (MULT_EXPR
, type
, TMR_STEP (base
), astep
);
1573 step
= fold_build2 (PLUS_EXPR
, type
, step
, astep
);
1581 base
= tree_mem_ref_addr (type
, base
);
1585 ifs_ivopts_data
.ivopts_data
= data
;
1586 ifs_ivopts_data
.stmt
= stmt
;
1587 ifs_ivopts_data
.step_p
= &step
;
1588 if (!for_each_index (&base
, idx_find_step
, &ifs_ivopts_data
)
1592 gcc_assert (TREE_CODE (base
) != ALIGN_INDIRECT_REF
);
1593 gcc_assert (TREE_CODE (base
) != MISALIGNED_INDIRECT_REF
);
1595 base
= build_fold_addr_expr (base
);
1598 civ
= alloc_iv (base
, step
);
1599 record_use (data
, op_p
, civ
, stmt
, USE_ADDRESS
);
1603 for_each_index (op_p
, idx_record_use
, data
);
1606 /* Finds and records invariants used in STMT. */
1609 find_invariants_stmt (struct ivopts_data
*data
, tree stmt
)
1612 use_operand_p use_p
;
1615 FOR_EACH_PHI_OR_STMT_USE (use_p
, stmt
, iter
, SSA_OP_USE
)
1617 op
= USE_FROM_PTR (use_p
);
1618 record_invariant (data
, op
, false);
1622 /* Finds interesting uses of induction variables in the statement STMT. */
1625 find_interesting_uses_stmt (struct ivopts_data
*data
, tree stmt
)
1630 use_operand_p use_p
;
1632 find_invariants_stmt (data
, stmt
);
1634 if (TREE_CODE (stmt
) == COND_EXPR
)
1636 find_interesting_uses_cond (data
, stmt
, &COND_EXPR_COND (stmt
));
1640 if (TREE_CODE (stmt
) == MODIFY_EXPR
)
1642 lhs
= TREE_OPERAND (stmt
, 0);
1643 rhs
= TREE_OPERAND (stmt
, 1);
1645 if (TREE_CODE (lhs
) == SSA_NAME
)
1647 /* If the statement defines an induction variable, the uses are not
1648 interesting by themselves. */
1650 iv
= get_iv (data
, lhs
);
1652 if (iv
&& !zero_p (iv
->step
))
1656 switch (TREE_CODE_CLASS (TREE_CODE (rhs
)))
1658 case tcc_comparison
:
1659 find_interesting_uses_cond (data
, stmt
, &TREE_OPERAND (stmt
, 1));
1663 find_interesting_uses_address (data
, stmt
, &TREE_OPERAND (stmt
, 1));
1664 if (REFERENCE_CLASS_P (lhs
))
1665 find_interesting_uses_address (data
, stmt
, &TREE_OPERAND (stmt
, 0));
1671 if (REFERENCE_CLASS_P (lhs
)
1672 && is_gimple_val (rhs
))
1674 find_interesting_uses_address (data
, stmt
, &TREE_OPERAND (stmt
, 0));
1675 find_interesting_uses_op (data
, rhs
);
1679 /* TODO -- we should also handle address uses of type
1681 memory = call (whatever);
1688 if (TREE_CODE (stmt
) == PHI_NODE
1689 && bb_for_stmt (stmt
) == data
->current_loop
->header
)
1691 lhs
= PHI_RESULT (stmt
);
1692 iv
= get_iv (data
, lhs
);
1694 if (iv
&& !zero_p (iv
->step
))
1698 FOR_EACH_PHI_OR_STMT_USE (use_p
, stmt
, iter
, SSA_OP_USE
)
1700 op
= USE_FROM_PTR (use_p
);
1702 if (TREE_CODE (op
) != SSA_NAME
)
1705 iv
= get_iv (data
, op
);
1709 find_interesting_uses_op (data
, op
);
1713 /* Finds interesting uses of induction variables outside of loops
1714 on loop exit edge EXIT. */
1717 find_interesting_uses_outside (struct ivopts_data
*data
, edge exit
)
1721 for (phi
= phi_nodes (exit
->dest
); phi
; phi
= PHI_CHAIN (phi
))
1723 def
= PHI_ARG_DEF_FROM_EDGE (phi
, exit
);
1724 find_interesting_uses_outer (data
, def
);
1728 /* Finds uses of the induction variables that are interesting. */
1731 find_interesting_uses (struct ivopts_data
*data
)
1734 block_stmt_iterator bsi
;
1736 basic_block
*body
= get_loop_body (data
->current_loop
);
1738 struct version_info
*info
;
1741 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1742 fprintf (dump_file
, "Uses:\n\n");
1744 for (i
= 0; i
< data
->current_loop
->num_nodes
; i
++)
1749 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1750 if (e
->dest
!= EXIT_BLOCK_PTR
1751 && !flow_bb_inside_loop_p (data
->current_loop
, e
->dest
))
1752 find_interesting_uses_outside (data
, e
);
1754 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
1755 find_interesting_uses_stmt (data
, phi
);
1756 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1757 find_interesting_uses_stmt (data
, bsi_stmt (bsi
));
1760 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1764 fprintf (dump_file
, "\n");
1766 EXECUTE_IF_SET_IN_BITMAP (data
->relevant
, 0, i
, bi
)
1768 info
= ver_info (data
, i
);
1771 fprintf (dump_file
, " ");
1772 print_generic_expr (dump_file
, info
->name
, TDF_SLIM
);
1773 fprintf (dump_file
, " is invariant (%d)%s\n",
1774 info
->inv_id
, info
->has_nonlin_use
? "" : ", eliminable");
1778 fprintf (dump_file
, "\n");
1784 /* Strips constant offsets from EXPR and stores them to OFFSET. If INSIDE_ADDR
1785 is true, assume we are inside an address. If TOP_COMPREF is true, assume
1786 we are at the top-level of the processed address. */
1789 strip_offset_1 (tree expr
, bool inside_addr
, bool top_compref
,
1790 unsigned HOST_WIDE_INT
*offset
)
1792 tree op0
= NULL_TREE
, op1
= NULL_TREE
, tmp
, step
;
1793 enum tree_code code
;
1794 tree type
, orig_type
= TREE_TYPE (expr
);
1795 unsigned HOST_WIDE_INT off0
, off1
, st
;
1796 tree orig_expr
= expr
;
1800 type
= TREE_TYPE (expr
);
1801 code
= TREE_CODE (expr
);
1807 if (!cst_and_fits_in_hwi (expr
)
1811 *offset
= int_cst_value (expr
);
1812 return build_int_cst_type (orig_type
, 0);
1816 op0
= TREE_OPERAND (expr
, 0);
1817 op1
= TREE_OPERAND (expr
, 1);
1819 op0
= strip_offset_1 (op0
, false, false, &off0
);
1820 op1
= strip_offset_1 (op1
, false, false, &off1
);
1822 *offset
= (code
== PLUS_EXPR
? off0
+ off1
: off0
- off1
);
1823 if (op0
== TREE_OPERAND (expr
, 0)
1824 && op1
== TREE_OPERAND (expr
, 1))
1829 else if (zero_p (op0
))
1831 if (code
== PLUS_EXPR
)
1834 expr
= fold_build1 (NEGATE_EXPR
, type
, op1
);
1837 expr
= fold_build2 (code
, type
, op0
, op1
);
1839 return fold_convert (orig_type
, expr
);
1845 step
= array_ref_element_size (expr
);
1846 if (!cst_and_fits_in_hwi (step
))
1849 st
= int_cst_value (step
);
1850 op1
= TREE_OPERAND (expr
, 1);
1851 op1
= strip_offset_1 (op1
, false, false, &off1
);
1852 *offset
= off1
* st
;
1857 /* Strip the component reference completely. */
1858 op0
= TREE_OPERAND (expr
, 0);
1859 op0
= strip_offset_1 (op0
, inside_addr
, top_compref
, &off0
);
1869 tmp
= component_ref_field_offset (expr
);
1871 && cst_and_fits_in_hwi (tmp
))
1873 /* Strip the component reference completely. */
1874 op0
= TREE_OPERAND (expr
, 0);
1875 op0
= strip_offset_1 (op0
, inside_addr
, top_compref
, &off0
);
1876 *offset
= off0
+ int_cst_value (tmp
);
1882 op0
= TREE_OPERAND (expr
, 0);
1883 op0
= strip_offset_1 (op0
, true, true, &off0
);
1886 if (op0
== TREE_OPERAND (expr
, 0))
1889 expr
= build_fold_addr_expr (op0
);
1890 return fold_convert (orig_type
, expr
);
1893 inside_addr
= false;
1900 /* Default handling of expressions for that we want to recurse into
1901 the first operand. */
1902 op0
= TREE_OPERAND (expr
, 0);
1903 op0
= strip_offset_1 (op0
, inside_addr
, false, &off0
);
1906 if (op0
== TREE_OPERAND (expr
, 0)
1907 && (!op1
|| op1
== TREE_OPERAND (expr
, 1)))
1910 expr
= copy_node (expr
);
1911 TREE_OPERAND (expr
, 0) = op0
;
1913 TREE_OPERAND (expr
, 1) = op1
;
1915 /* Inside address, we might strip the top level component references,
1916 thus changing type of the expression. Handling of ADDR_EXPR
1918 expr
= fold_convert (orig_type
, expr
);
1923 /* Strips constant offsets from EXPR and stores them to OFFSET. */
1926 strip_offset (tree expr
, unsigned HOST_WIDE_INT
*offset
)
1928 return strip_offset_1 (expr
, false, false, offset
);
1931 /* Returns variant of TYPE that can be used as base for different uses.
1932 For integer types, we return unsigned variant of the type, which
1933 avoids problems with overflows. For pointer types, we return void *. */
1936 generic_type_for (tree type
)
1938 if (POINTER_TYPE_P (type
))
1939 return ptr_type_node
;
1941 if (TYPE_UNSIGNED (type
))
1944 return unsigned_type_for (type
);
1947 /* Records invariants in *EXPR_P. Callback for walk_tree. DATA contains
1948 the bitmap to that we should store it. */
1950 static struct ivopts_data
*fd_ivopts_data
;
1952 find_depends (tree
*expr_p
, int *ws ATTRIBUTE_UNUSED
, void *data
)
1954 bitmap
*depends_on
= data
;
1955 struct version_info
*info
;
1957 if (TREE_CODE (*expr_p
) != SSA_NAME
)
1959 info
= name_info (fd_ivopts_data
, *expr_p
);
1961 if (!info
->inv_id
|| info
->has_nonlin_use
)
1965 *depends_on
= BITMAP_ALLOC (NULL
);
1966 bitmap_set_bit (*depends_on
, info
->inv_id
);
1971 /* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and
1972 position to POS. If USE is not NULL, the candidate is set as related to
1973 it. If both BASE and STEP are NULL, we add a pseudocandidate for the
1974 replacement of the final value of the iv by a direct computation. */
1976 static struct iv_cand
*
1977 add_candidate_1 (struct ivopts_data
*data
,
1978 tree base
, tree step
, bool important
, enum iv_position pos
,
1979 struct iv_use
*use
, tree incremented_at
)
1982 struct iv_cand
*cand
= NULL
;
1983 tree type
, orig_type
;
1987 orig_type
= TREE_TYPE (base
);
1988 type
= generic_type_for (orig_type
);
1989 if (type
!= orig_type
)
1991 base
= fold_convert (type
, base
);
1993 step
= fold_convert (type
, step
);
1997 for (i
= 0; i
< n_iv_cands (data
); i
++)
1999 cand
= iv_cand (data
, i
);
2001 if (cand
->pos
!= pos
)
2004 if (cand
->incremented_at
!= incremented_at
)
2018 if (!operand_equal_p (base
, cand
->iv
->base
, 0))
2021 if (zero_p (cand
->iv
->step
))
2028 if (step
&& operand_equal_p (step
, cand
->iv
->step
, 0))
2033 if (i
== n_iv_cands (data
))
2035 cand
= xcalloc (1, sizeof (struct iv_cand
));
2041 cand
->iv
= alloc_iv (base
, step
);
2044 if (pos
!= IP_ORIGINAL
&& cand
->iv
)
2046 cand
->var_before
= create_tmp_var_raw (TREE_TYPE (base
), "ivtmp");
2047 cand
->var_after
= cand
->var_before
;
2049 cand
->important
= important
;
2050 cand
->incremented_at
= incremented_at
;
2051 VEC_safe_push (iv_cand_p
, heap
, data
->iv_candidates
, cand
);
2054 && TREE_CODE (step
) != INTEGER_CST
)
2056 fd_ivopts_data
= data
;
2057 walk_tree (&step
, find_depends
, &cand
->depends_on
, NULL
);
2060 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2061 dump_cand (dump_file
, cand
);
2064 if (important
&& !cand
->important
)
2066 cand
->important
= true;
2067 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2068 fprintf (dump_file
, "Candidate %d is important\n", cand
->id
);
2073 bitmap_set_bit (use
->related_cands
, i
);
2074 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2075 fprintf (dump_file
, "Candidate %d is related to use %d\n",
2082 /* Returns true if incrementing the induction variable at the end of the LOOP
2085 The purpose is to avoid splitting latch edge with a biv increment, thus
2086 creating a jump, possibly confusing other optimization passes and leaving
2087 less freedom to scheduler. So we allow IP_END_POS only if IP_NORMAL_POS
2088 is not available (so we do not have a better alternative), or if the latch
2089 edge is already nonempty. */
2092 allow_ip_end_pos_p (struct loop
*loop
)
2094 if (!ip_normal_pos (loop
))
2097 if (!empty_block_p (ip_end_pos (loop
)))
2103 /* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and
2104 position to POS. If USE is not NULL, the candidate is set as related to
2105 it. The candidate computation is scheduled on all available positions. */
2108 add_candidate (struct ivopts_data
*data
,
2109 tree base
, tree step
, bool important
, struct iv_use
*use
)
2111 if (ip_normal_pos (data
->current_loop
))
2112 add_candidate_1 (data
, base
, step
, important
, IP_NORMAL
, use
, NULL_TREE
);
2113 if (ip_end_pos (data
->current_loop
)
2114 && allow_ip_end_pos_p (data
->current_loop
))
2115 add_candidate_1 (data
, base
, step
, important
, IP_END
, use
, NULL_TREE
);
2118 /* Add a standard "0 + 1 * iteration" iv candidate for a
2119 type with SIZE bits. */
2122 add_standard_iv_candidates_for_size (struct ivopts_data
*data
,
2125 tree type
= lang_hooks
.types
.type_for_size (size
, true);
2126 add_candidate (data
, build_int_cst (type
, 0), build_int_cst (type
, 1),
2130 /* Adds standard iv candidates. */
2133 add_standard_iv_candidates (struct ivopts_data
*data
)
2135 add_standard_iv_candidates_for_size (data
, INT_TYPE_SIZE
);
2137 /* The same for a double-integer type if it is still fast enough. */
2138 if (BITS_PER_WORD
>= INT_TYPE_SIZE
* 2)
2139 add_standard_iv_candidates_for_size (data
, INT_TYPE_SIZE
* 2);
2143 /* Adds candidates bases on the old induction variable IV. */
2146 add_old_iv_candidates (struct ivopts_data
*data
, struct iv
*iv
)
2149 struct iv_cand
*cand
;
2151 add_candidate (data
, iv
->base
, iv
->step
, true, NULL
);
2153 /* The same, but with initial value zero. */
2154 add_candidate (data
,
2155 build_int_cst (TREE_TYPE (iv
->base
), 0),
2156 iv
->step
, true, NULL
);
2158 phi
= SSA_NAME_DEF_STMT (iv
->ssa_name
);
2159 if (TREE_CODE (phi
) == PHI_NODE
)
2161 /* Additionally record the possibility of leaving the original iv
2163 def
= PHI_ARG_DEF_FROM_EDGE (phi
, loop_latch_edge (data
->current_loop
));
2164 cand
= add_candidate_1 (data
,
2165 iv
->base
, iv
->step
, true, IP_ORIGINAL
, NULL
,
2166 SSA_NAME_DEF_STMT (def
));
2167 cand
->var_before
= iv
->ssa_name
;
2168 cand
->var_after
= def
;
2172 /* Adds candidates based on the old induction variables. */
2175 add_old_ivs_candidates (struct ivopts_data
*data
)
2181 EXECUTE_IF_SET_IN_BITMAP (data
->relevant
, 0, i
, bi
)
2183 iv
= ver_info (data
, i
)->iv
;
2184 if (iv
&& iv
->biv_p
&& !zero_p (iv
->step
))
2185 add_old_iv_candidates (data
, iv
);
2189 /* Adds candidates based on the value of the induction variable IV and USE. */
2192 add_iv_value_candidates (struct ivopts_data
*data
,
2193 struct iv
*iv
, struct iv_use
*use
)
2195 unsigned HOST_WIDE_INT offset
;
2198 add_candidate (data
, iv
->base
, iv
->step
, false, use
);
2200 /* The same, but with initial value zero. Make such variable important,
2201 since it is generic enough so that possibly many uses may be based
2203 add_candidate (data
, build_int_cst (TREE_TYPE (iv
->base
), 0),
2204 iv
->step
, true, use
);
2206 /* Third, try removing the constant offset. */
2207 base
= strip_offset (iv
->base
, &offset
);
2209 add_candidate (data
, base
, iv
->step
, false, use
);
2212 /* Possibly adds pseudocandidate for replacing the final value of USE by
2213 a direct computation. */
2216 add_iv_outer_candidates (struct ivopts_data
*data
, struct iv_use
*use
)
2218 struct tree_niter_desc
*niter
;
2220 /* We must know where we exit the loop and how many times does it roll. */
2221 niter
= niter_for_single_dom_exit (data
);
2223 || !zero_p (niter
->may_be_zero
))
2226 add_candidate_1 (data
, NULL
, NULL
, false, IP_NORMAL
, use
, NULL_TREE
);
2229 /* Adds candidates based on the uses. */
2232 add_derived_ivs_candidates (struct ivopts_data
*data
)
2236 for (i
= 0; i
< n_iv_uses (data
); i
++)
2238 struct iv_use
*use
= iv_use (data
, i
);
2245 case USE_NONLINEAR_EXPR
:
2248 /* Just add the ivs based on the value of the iv used here. */
2249 add_iv_value_candidates (data
, use
->iv
, use
);
2253 add_iv_value_candidates (data
, use
->iv
, use
);
2255 /* Additionally, add the pseudocandidate for the possibility to
2256 replace the final value by a direct computation. */
2257 add_iv_outer_candidates (data
, use
);
2266 /* Record important candidates and add them to related_cands bitmaps
2270 record_important_candidates (struct ivopts_data
*data
)
2275 for (i
= 0; i
< n_iv_cands (data
); i
++)
2277 struct iv_cand
*cand
= iv_cand (data
, i
);
2279 if (cand
->important
)
2280 bitmap_set_bit (data
->important_candidates
, i
);
2283 data
->consider_all_candidates
= (n_iv_cands (data
)
2284 <= CONSIDER_ALL_CANDIDATES_BOUND
);
2286 if (data
->consider_all_candidates
)
2288 /* We will not need "related_cands" bitmaps in this case,
2289 so release them to decrease peak memory consumption. */
2290 for (i
= 0; i
< n_iv_uses (data
); i
++)
2292 use
= iv_use (data
, i
);
2293 BITMAP_FREE (use
->related_cands
);
2298 /* Add important candidates to the related_cands bitmaps. */
2299 for (i
= 0; i
< n_iv_uses (data
); i
++)
2300 bitmap_ior_into (iv_use (data
, i
)->related_cands
,
2301 data
->important_candidates
);
2305 /* Finds the candidates for the induction variables. */
2308 find_iv_candidates (struct ivopts_data
*data
)
2310 /* Add commonly used ivs. */
2311 add_standard_iv_candidates (data
);
2313 /* Add old induction variables. */
2314 add_old_ivs_candidates (data
);
2316 /* Add induction variables derived from uses. */
2317 add_derived_ivs_candidates (data
);
2319 /* Record the important candidates. */
2320 record_important_candidates (data
);
2323 /* Allocates the data structure mapping the (use, candidate) pairs to costs.
2324 If consider_all_candidates is true, we use a two-dimensional array, otherwise
2325 we allocate a simple list to every use. */
2328 alloc_use_cost_map (struct ivopts_data
*data
)
2330 unsigned i
, size
, s
, j
;
2332 for (i
= 0; i
< n_iv_uses (data
); i
++)
2334 struct iv_use
*use
= iv_use (data
, i
);
2337 if (data
->consider_all_candidates
)
2338 size
= n_iv_cands (data
);
2342 EXECUTE_IF_SET_IN_BITMAP (use
->related_cands
, 0, j
, bi
)
2347 /* Round up to the power of two, so that moduling by it is fast. */
2348 for (size
= 1; size
< s
; size
<<= 1)
2352 use
->n_map_members
= size
;
2353 use
->cost_map
= xcalloc (size
, sizeof (struct cost_pair
));
2357 /* Sets cost of (USE, CANDIDATE) pair to COST and record that it depends
2358 on invariants DEPENDS_ON and that the value used in expressing it
2362 set_use_iv_cost (struct ivopts_data
*data
,
2363 struct iv_use
*use
, struct iv_cand
*cand
, unsigned cost
,
2364 bitmap depends_on
, tree value
)
2370 BITMAP_FREE (depends_on
);
2374 if (data
->consider_all_candidates
)
2376 use
->cost_map
[cand
->id
].cand
= cand
;
2377 use
->cost_map
[cand
->id
].cost
= cost
;
2378 use
->cost_map
[cand
->id
].depends_on
= depends_on
;
2379 use
->cost_map
[cand
->id
].value
= value
;
2383 /* n_map_members is a power of two, so this computes modulo. */
2384 s
= cand
->id
& (use
->n_map_members
- 1);
2385 for (i
= s
; i
< use
->n_map_members
; i
++)
2386 if (!use
->cost_map
[i
].cand
)
2388 for (i
= 0; i
< s
; i
++)
2389 if (!use
->cost_map
[i
].cand
)
2395 use
->cost_map
[i
].cand
= cand
;
2396 use
->cost_map
[i
].cost
= cost
;
2397 use
->cost_map
[i
].depends_on
= depends_on
;
2398 use
->cost_map
[i
].value
= value
;
2401 /* Gets cost of (USE, CANDIDATE) pair. */
2403 static struct cost_pair
*
2404 get_use_iv_cost (struct ivopts_data
*data
, struct iv_use
*use
,
2405 struct iv_cand
*cand
)
2408 struct cost_pair
*ret
;
2413 if (data
->consider_all_candidates
)
2415 ret
= use
->cost_map
+ cand
->id
;
2422 /* n_map_members is a power of two, so this computes modulo. */
2423 s
= cand
->id
& (use
->n_map_members
- 1);
2424 for (i
= s
; i
< use
->n_map_members
; i
++)
2425 if (use
->cost_map
[i
].cand
== cand
)
2426 return use
->cost_map
+ i
;
2428 for (i
= 0; i
< s
; i
++)
2429 if (use
->cost_map
[i
].cand
== cand
)
2430 return use
->cost_map
+ i
;
2435 /* Returns estimate on cost of computing SEQ. */
2443 for (; seq
; seq
= NEXT_INSN (seq
))
2445 set
= single_set (seq
);
2447 cost
+= rtx_cost (set
, SET
);
2455 /* Produce DECL_RTL for object obj so it looks like it is stored in memory. */
2457 produce_memory_decl_rtl (tree obj
, int *regno
)
2462 if (TREE_STATIC (obj
) || DECL_EXTERNAL (obj
))
2464 const char *name
= IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (obj
));
2465 x
= gen_rtx_SYMBOL_REF (Pmode
, name
);
2468 x
= gen_raw_REG (Pmode
, (*regno
)++);
2470 return gen_rtx_MEM (DECL_MODE (obj
), x
);
2473 /* Prepares decl_rtl for variables referred in *EXPR_P. Callback for
2474 walk_tree. DATA contains the actual fake register number. */
2477 prepare_decl_rtl (tree
*expr_p
, int *ws
, void *data
)
2479 tree obj
= NULL_TREE
;
2483 switch (TREE_CODE (*expr_p
))
2486 for (expr_p
= &TREE_OPERAND (*expr_p
, 0);
2487 handled_component_p (*expr_p
);
2488 expr_p
= &TREE_OPERAND (*expr_p
, 0))
2492 x
= produce_memory_decl_rtl (obj
, regno
);
2497 obj
= SSA_NAME_VAR (*expr_p
);
2498 if (!DECL_RTL_SET_P (obj
))
2499 x
= gen_raw_REG (DECL_MODE (obj
), (*regno
)++);
2508 if (DECL_RTL_SET_P (obj
))
2511 if (DECL_MODE (obj
) == BLKmode
)
2512 x
= produce_memory_decl_rtl (obj
, regno
);
2514 x
= gen_raw_REG (DECL_MODE (obj
), (*regno
)++);
2524 VEC_safe_push (tree
, heap
, decl_rtl_to_reset
, obj
);
2525 SET_DECL_RTL (obj
, x
);
2531 /* Determines cost of the computation of EXPR. */
2534 computation_cost (tree expr
)
2537 tree type
= TREE_TYPE (expr
);
2539 /* Avoid using hard regs in ways which may be unsupported. */
2540 int regno
= LAST_VIRTUAL_REGISTER
+ 1;
2542 walk_tree (&expr
, prepare_decl_rtl
, ®no
, NULL
);
2544 rslt
= expand_expr (expr
, NULL_RTX
, TYPE_MODE (type
), EXPAND_NORMAL
);
2548 cost
= seq_cost (seq
);
2550 cost
+= address_cost (XEXP (rslt
, 0), TYPE_MODE (type
));
2555 /* Returns variable containing the value of candidate CAND at statement AT. */
2558 var_at_stmt (struct loop
*loop
, struct iv_cand
*cand
, tree stmt
)
2560 if (stmt_after_increment (loop
, cand
, stmt
))
2561 return cand
->var_after
;
2563 return cand
->var_before
;
2566 /* Return the most significant (sign) bit of T. Similar to tree_int_cst_msb,
2567 but the bit is determined from TYPE_PRECISION, not MODE_BITSIZE. */
2570 tree_int_cst_sign_bit (tree t
)
2572 unsigned bitno
= TYPE_PRECISION (TREE_TYPE (t
)) - 1;
2573 unsigned HOST_WIDE_INT w
;
2575 if (bitno
< HOST_BITS_PER_WIDE_INT
)
2576 w
= TREE_INT_CST_LOW (t
);
2579 w
= TREE_INT_CST_HIGH (t
);
2580 bitno
-= HOST_BITS_PER_WIDE_INT
;
2583 return (w
>> bitno
) & 1;
2586 /* If we can prove that TOP = cst * BOT for some constant cst in TYPE,
2587 return cst. Otherwise return NULL_TREE. */
2590 constant_multiple_of (tree type
, tree top
, tree bot
)
2592 tree res
, mby
, p0
, p1
;
2593 enum tree_code code
;
2599 if (operand_equal_p (top
, bot
, 0))
2600 return build_int_cst (type
, 1);
2602 code
= TREE_CODE (top
);
2606 mby
= TREE_OPERAND (top
, 1);
2607 if (TREE_CODE (mby
) != INTEGER_CST
)
2610 res
= constant_multiple_of (type
, TREE_OPERAND (top
, 0), bot
);
2614 return fold_binary_to_constant (MULT_EXPR
, type
, res
,
2615 fold_convert (type
, mby
));
2619 p0
= constant_multiple_of (type
, TREE_OPERAND (top
, 0), bot
);
2622 p1
= constant_multiple_of (type
, TREE_OPERAND (top
, 1), bot
);
2626 return fold_binary_to_constant (code
, type
, p0
, p1
);
2629 if (TREE_CODE (bot
) != INTEGER_CST
)
2632 bot
= fold_convert (type
, bot
);
2633 top
= fold_convert (type
, top
);
2635 /* If BOT seems to be negative, try dividing by -BOT instead, and negate
2636 the result afterwards. */
2637 if (tree_int_cst_sign_bit (bot
))
2640 bot
= fold_unary_to_constant (NEGATE_EXPR
, type
, bot
);
2645 /* Ditto for TOP. */
2646 if (tree_int_cst_sign_bit (top
))
2649 top
= fold_unary_to_constant (NEGATE_EXPR
, type
, top
);
2652 if (!zero_p (fold_binary_to_constant (TRUNC_MOD_EXPR
, type
, top
, bot
)))
2655 res
= fold_binary_to_constant (EXACT_DIV_EXPR
, type
, top
, bot
);
2657 res
= fold_unary_to_constant (NEGATE_EXPR
, type
, res
);
2665 /* Sets COMB to CST. */
2668 aff_combination_const (struct affine_tree_combination
*comb
, tree type
,
2669 unsigned HOST_WIDE_INT cst
)
2671 unsigned prec
= TYPE_PRECISION (type
);
2674 comb
->mask
= (((unsigned HOST_WIDE_INT
) 2 << (prec
- 1)) - 1);
2677 comb
->rest
= NULL_TREE
;
2678 comb
->offset
= cst
& comb
->mask
;
2681 /* Sets COMB to single element ELT. */
2684 aff_combination_elt (struct affine_tree_combination
*comb
, tree type
, tree elt
)
2686 unsigned prec
= TYPE_PRECISION (type
);
2689 comb
->mask
= (((unsigned HOST_WIDE_INT
) 2 << (prec
- 1)) - 1);
2692 comb
->elts
[0] = elt
;
2694 comb
->rest
= NULL_TREE
;
2698 /* Scales COMB by SCALE. */
2701 aff_combination_scale (struct affine_tree_combination
*comb
,
2702 unsigned HOST_WIDE_INT scale
)
2711 aff_combination_const (comb
, comb
->type
, 0);
2715 comb
->offset
= (scale
* comb
->offset
) & comb
->mask
;
2716 for (i
= 0, j
= 0; i
< comb
->n
; i
++)
2718 comb
->coefs
[j
] = (scale
* comb
->coefs
[i
]) & comb
->mask
;
2719 comb
->elts
[j
] = comb
->elts
[i
];
2720 if (comb
->coefs
[j
] != 0)
2727 if (comb
->n
< MAX_AFF_ELTS
)
2729 comb
->coefs
[comb
->n
] = scale
;
2730 comb
->elts
[comb
->n
] = comb
->rest
;
2731 comb
->rest
= NULL_TREE
;
2735 comb
->rest
= fold_build2 (MULT_EXPR
, comb
->type
, comb
->rest
,
2736 build_int_cst_type (comb
->type
, scale
));
2740 /* Adds ELT * SCALE to COMB. */
2743 aff_combination_add_elt (struct affine_tree_combination
*comb
, tree elt
,
2744 unsigned HOST_WIDE_INT scale
)
2751 for (i
= 0; i
< comb
->n
; i
++)
2752 if (operand_equal_p (comb
->elts
[i
], elt
, 0))
2754 comb
->coefs
[i
] = (comb
->coefs
[i
] + scale
) & comb
->mask
;
2759 comb
->coefs
[i
] = comb
->coefs
[comb
->n
];
2760 comb
->elts
[i
] = comb
->elts
[comb
->n
];
2763 if (comb
->n
< MAX_AFF_ELTS
)
2765 comb
->coefs
[comb
->n
] = scale
;
2766 comb
->elts
[comb
->n
] = elt
;
2772 elt
= fold_convert (comb
->type
, elt
);
2774 elt
= fold_build2 (MULT_EXPR
, comb
->type
,
2775 fold_convert (comb
->type
, elt
),
2776 build_int_cst_type (comb
->type
, scale
));
2779 comb
->rest
= fold_build2 (PLUS_EXPR
, comb
->type
, comb
->rest
, elt
);
2784 /* Adds COMB2 to COMB1. */
2787 aff_combination_add (struct affine_tree_combination
*comb1
,
2788 struct affine_tree_combination
*comb2
)
2792 comb1
->offset
= (comb1
->offset
+ comb2
->offset
) & comb1
->mask
;
2793 for (i
= 0; i
< comb2
-> n
; i
++)
2794 aff_combination_add_elt (comb1
, comb2
->elts
[i
], comb2
->coefs
[i
]);
2796 aff_combination_add_elt (comb1
, comb2
->rest
, 1);
2799 /* Splits EXPR into an affine combination of parts. */
2802 tree_to_aff_combination (tree expr
, tree type
,
2803 struct affine_tree_combination
*comb
)
2805 struct affine_tree_combination tmp
;
2806 enum tree_code code
;
2807 tree cst
, core
, toffset
;
2808 HOST_WIDE_INT bitpos
, bitsize
;
2809 enum machine_mode mode
;
2810 int unsignedp
, volatilep
;
2814 code
= TREE_CODE (expr
);
2818 aff_combination_const (comb
, type
, int_cst_value (expr
));
2823 tree_to_aff_combination (TREE_OPERAND (expr
, 0), type
, comb
);
2824 tree_to_aff_combination (TREE_OPERAND (expr
, 1), type
, &tmp
);
2825 if (code
== MINUS_EXPR
)
2826 aff_combination_scale (&tmp
, -1);
2827 aff_combination_add (comb
, &tmp
);
2831 cst
= TREE_OPERAND (expr
, 1);
2832 if (TREE_CODE (cst
) != INTEGER_CST
)
2834 tree_to_aff_combination (TREE_OPERAND (expr
, 0), type
, comb
);
2835 aff_combination_scale (comb
, int_cst_value (cst
));
2839 tree_to_aff_combination (TREE_OPERAND (expr
, 0), type
, comb
);
2840 aff_combination_scale (comb
, -1);
2844 core
= get_inner_reference (TREE_OPERAND (expr
, 0), &bitsize
, &bitpos
,
2845 &toffset
, &mode
, &unsignedp
, &volatilep
,
2847 if (bitpos
% BITS_PER_UNIT
!= 0)
2849 aff_combination_const (comb
, type
, bitpos
/ BITS_PER_UNIT
);
2850 core
= build_fold_addr_expr (core
);
2851 if (TREE_CODE (core
) == ADDR_EXPR
)
2852 aff_combination_add_elt (comb
, core
, 1);
2855 tree_to_aff_combination (core
, type
, &tmp
);
2856 aff_combination_add (comb
, &tmp
);
2860 tree_to_aff_combination (toffset
, type
, &tmp
);
2861 aff_combination_add (comb
, &tmp
);
2869 aff_combination_elt (comb
, type
, expr
);
2872 /* Creates EXPR + ELT * SCALE in TYPE. MASK is the mask for width of TYPE. */
2875 add_elt_to_tree (tree expr
, tree type
, tree elt
, unsigned HOST_WIDE_INT scale
,
2876 unsigned HOST_WIDE_INT mask
)
2878 enum tree_code code
;
2881 elt
= fold_convert (type
, elt
);
2888 return fold_build2 (PLUS_EXPR
, type
, expr
, elt
);
2894 return fold_build1 (NEGATE_EXPR
, type
, elt
);
2896 return fold_build2 (MINUS_EXPR
, type
, expr
, elt
);
2900 return fold_build2 (MULT_EXPR
, type
, elt
,
2901 build_int_cst_type (type
, scale
));
2903 if ((scale
| (mask
>> 1)) == mask
)
2905 /* Scale is negative. */
2907 scale
= (-scale
) & mask
;
2912 elt
= fold_build2 (MULT_EXPR
, type
, elt
,
2913 build_int_cst_type (type
, scale
));
2914 return fold_build2 (code
, type
, expr
, elt
);
2917 /* Copies the tree elements of COMB to ensure that they are not shared. */
2920 unshare_aff_combination (struct affine_tree_combination
*comb
)
2924 for (i
= 0; i
< comb
->n
; i
++)
2925 comb
->elts
[i
] = unshare_expr (comb
->elts
[i
]);
2927 comb
->rest
= unshare_expr (comb
->rest
);
2930 /* Makes tree from the affine combination COMB. */
2933 aff_combination_to_tree (struct affine_tree_combination
*comb
)
2935 tree type
= comb
->type
;
2936 tree expr
= comb
->rest
;
2938 unsigned HOST_WIDE_INT off
, sgn
;
2940 /* Handle the special case produced by get_computation_aff when
2941 the type does not fit in HOST_WIDE_INT. */
2942 if (comb
->n
== 0 && comb
->offset
== 0)
2943 return fold_convert (type
, expr
);
2945 gcc_assert (comb
->n
== MAX_AFF_ELTS
|| comb
->rest
== NULL_TREE
);
2947 for (i
= 0; i
< comb
->n
; i
++)
2948 expr
= add_elt_to_tree (expr
, type
, comb
->elts
[i
], comb
->coefs
[i
],
2951 if ((comb
->offset
| (comb
->mask
>> 1)) == comb
->mask
)
2953 /* Offset is negative. */
2954 off
= (-comb
->offset
) & comb
->mask
;
2962 return add_elt_to_tree (expr
, type
, build_int_cst_type (type
, off
), sgn
,
2966 /* Determines the expression by that USE is expressed from induction variable
2967 CAND at statement AT in LOOP. The expression is stored in a decomposed
2968 form into AFF. Returns false if USE cannot be expressed using CAND. */
2971 get_computation_aff (struct loop
*loop
,
2972 struct iv_use
*use
, struct iv_cand
*cand
, tree at
,
2973 struct affine_tree_combination
*aff
)
2975 tree ubase
= use
->iv
->base
;
2976 tree ustep
= use
->iv
->step
;
2977 tree cbase
= cand
->iv
->base
;
2978 tree cstep
= cand
->iv
->step
;
2979 tree utype
= TREE_TYPE (ubase
), ctype
= TREE_TYPE (cbase
);
2983 unsigned HOST_WIDE_INT ustepi
, cstepi
;
2984 HOST_WIDE_INT ratioi
;
2985 struct affine_tree_combination cbase_aff
, expr_aff
;
2986 tree cstep_orig
= cstep
, ustep_orig
= ustep
;
2988 if (TYPE_PRECISION (utype
) > TYPE_PRECISION (ctype
))
2990 /* We do not have a precision to express the values of use. */
2994 expr
= var_at_stmt (loop
, cand
, at
);
2996 if (TREE_TYPE (expr
) != ctype
)
2998 /* This may happen with the original ivs. */
2999 expr
= fold_convert (ctype
, expr
);
3002 if (TYPE_UNSIGNED (utype
))
3006 uutype
= unsigned_type_for (utype
);
3007 ubase
= fold_convert (uutype
, ubase
);
3008 ustep
= fold_convert (uutype
, ustep
);
3011 if (uutype
!= ctype
)
3013 expr
= fold_convert (uutype
, expr
);
3014 cbase
= fold_convert (uutype
, cbase
);
3015 cstep
= fold_convert (uutype
, cstep
);
3017 /* If the conversion is not noop, we must take it into account when
3018 considering the value of the step. */
3019 if (TYPE_PRECISION (utype
) < TYPE_PRECISION (ctype
))
3023 if (cst_and_fits_in_hwi (cstep_orig
)
3024 && cst_and_fits_in_hwi (ustep_orig
))
3026 ustepi
= int_cst_value (ustep_orig
);
3027 cstepi
= int_cst_value (cstep_orig
);
3029 if (!divide (TYPE_PRECISION (uutype
), ustepi
, cstepi
, &ratioi
))
3031 /* TODO maybe consider case when ustep divides cstep and the ratio is
3032 a power of 2 (so that the division is fast to execute)? We would
3033 need to be much more careful with overflows etc. then. */
3037 ratio
= build_int_cst_type (uutype
, ratioi
);
3041 ratio
= constant_multiple_of (uutype
, ustep_orig
, cstep_orig
);
3045 /* Ratioi is only used to detect special cases when the multiplicative
3046 factor is 1 or -1, so if we cannot convert ratio to HOST_WIDE_INT,
3047 we may set it to 0. We prefer cst_and_fits_in_hwi/int_cst_value
3048 to integer_onep/integer_all_onesp, since the former ignores
3050 if (cst_and_fits_in_hwi (ratio
))
3051 ratioi
= int_cst_value (ratio
);
3052 else if (integer_onep (ratio
))
3054 else if (integer_all_onesp (ratio
))
3060 /* We may need to shift the value if we are after the increment. */
3061 if (stmt_after_increment (loop
, cand
, at
))
3062 cbase
= fold_build2 (PLUS_EXPR
, uutype
, cbase
, cstep
);
3064 /* use = ubase - ratio * cbase + ratio * var.
3066 In general case ubase + ratio * (var - cbase) could be better (one less
3067 multiplication), but often it is possible to eliminate redundant parts
3068 of computations from (ubase - ratio * cbase) term, and if it does not
3069 happen, fold is able to apply the distributive law to obtain this form
3072 if (TYPE_PRECISION (uutype
) > HOST_BITS_PER_WIDE_INT
)
3074 /* Let's compute in trees and just return the result in AFF. This case
3075 should not be very common, and fold itself is not that bad either,
3076 so making the aff. functions more complicated to handle this case
3077 is not that urgent. */
3080 delta
= fold_build2 (MINUS_EXPR
, uutype
, ubase
, cbase
);
3081 expr
= fold_build2 (PLUS_EXPR
, uutype
, expr
, delta
);
3083 else if (ratioi
== -1)
3085 delta
= fold_build2 (PLUS_EXPR
, uutype
, ubase
, cbase
);
3086 expr
= fold_build2 (MINUS_EXPR
, uutype
, delta
, expr
);
3090 delta
= fold_build2 (MULT_EXPR
, uutype
, cbase
, ratio
);
3091 delta
= fold_build2 (MINUS_EXPR
, uutype
, ubase
, delta
);
3092 expr
= fold_build2 (MULT_EXPR
, uutype
, ratio
, expr
);
3093 expr
= fold_build2 (PLUS_EXPR
, uutype
, delta
, expr
);
3104 /* If we got here, the types fits in HOST_WIDE_INT, thus it must be
3105 possible to compute ratioi. */
3106 gcc_assert (ratioi
);
3108 tree_to_aff_combination (ubase
, uutype
, aff
);
3109 tree_to_aff_combination (cbase
, uutype
, &cbase_aff
);
3110 tree_to_aff_combination (expr
, uutype
, &expr_aff
);
3111 aff_combination_scale (&cbase_aff
, -ratioi
);
3112 aff_combination_scale (&expr_aff
, ratioi
);
3113 aff_combination_add (aff
, &cbase_aff
);
3114 aff_combination_add (aff
, &expr_aff
);
3119 /* Determines the expression by that USE is expressed from induction variable
3120 CAND at statement AT in LOOP. The computation is unshared. */
3123 get_computation_at (struct loop
*loop
,
3124 struct iv_use
*use
, struct iv_cand
*cand
, tree at
)
3126 struct affine_tree_combination aff
;
3127 tree type
= TREE_TYPE (use
->iv
->base
);
3129 if (!get_computation_aff (loop
, use
, cand
, at
, &aff
))
3131 unshare_aff_combination (&aff
);
3132 return fold_convert (type
, aff_combination_to_tree (&aff
));
3135 /* Determines the expression by that USE is expressed from induction variable
3136 CAND in LOOP. The computation is unshared. */
3139 get_computation (struct loop
*loop
, struct iv_use
*use
, struct iv_cand
*cand
)
3141 return get_computation_at (loop
, use
, cand
, use
->stmt
);
3144 /* Returns cost of addition in MODE. */
3147 add_cost (enum machine_mode mode
)
3149 static unsigned costs
[NUM_MACHINE_MODES
];
3157 force_operand (gen_rtx_fmt_ee (PLUS
, mode
,
3158 gen_raw_REG (mode
, LAST_VIRTUAL_REGISTER
+ 1),
3159 gen_raw_REG (mode
, LAST_VIRTUAL_REGISTER
+ 2)),
3164 cost
= seq_cost (seq
);
3170 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3171 fprintf (dump_file
, "Addition in %s costs %d\n",
3172 GET_MODE_NAME (mode
), cost
);
3176 /* Entry in a hashtable of already known costs for multiplication. */
3179 HOST_WIDE_INT cst
; /* The constant to multiply by. */
3180 enum machine_mode mode
; /* In mode. */
3181 unsigned cost
; /* The cost. */
3184 /* Counts hash value for the ENTRY. */
3187 mbc_entry_hash (const void *entry
)
3189 const struct mbc_entry
*e
= entry
;
3191 return 57 * (hashval_t
) e
->mode
+ (hashval_t
) (e
->cst
% 877);
3194 /* Compares the hash table entries ENTRY1 and ENTRY2. */
3197 mbc_entry_eq (const void *entry1
, const void *entry2
)
3199 const struct mbc_entry
*e1
= entry1
;
3200 const struct mbc_entry
*e2
= entry2
;
3202 return (e1
->mode
== e2
->mode
3203 && e1
->cst
== e2
->cst
);
3206 /* Returns cost of multiplication by constant CST in MODE. */
3209 multiply_by_cost (HOST_WIDE_INT cst
, enum machine_mode mode
)
3211 static htab_t costs
;
3212 struct mbc_entry
**cached
, act
;
3217 costs
= htab_create (100, mbc_entry_hash
, mbc_entry_eq
, free
);
3221 cached
= (struct mbc_entry
**) htab_find_slot (costs
, &act
, INSERT
);
3223 return (*cached
)->cost
;
3225 *cached
= xmalloc (sizeof (struct mbc_entry
));
3226 (*cached
)->mode
= mode
;
3227 (*cached
)->cst
= cst
;
3230 expand_mult (mode
, gen_raw_REG (mode
, LAST_VIRTUAL_REGISTER
+ 1),
3231 gen_int_mode (cst
, mode
), NULL_RTX
, 0);
3235 cost
= seq_cost (seq
);
3237 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3238 fprintf (dump_file
, "Multiplication by %d in %s costs %d\n",
3239 (int) cst
, GET_MODE_NAME (mode
), cost
);
3241 (*cached
)->cost
= cost
;
3246 /* Returns true if multiplying by RATIO is allowed in address. */
3249 multiplier_allowed_in_address_p (HOST_WIDE_INT ratio
)
3251 #define MAX_RATIO 128
3252 static sbitmap valid_mult
;
3256 rtx reg1
= gen_raw_REG (Pmode
, LAST_VIRTUAL_REGISTER
+ 1);
3260 valid_mult
= sbitmap_alloc (2 * MAX_RATIO
+ 1);
3261 sbitmap_zero (valid_mult
);
3262 addr
= gen_rtx_fmt_ee (MULT
, Pmode
, reg1
, NULL_RTX
);
3263 for (i
= -MAX_RATIO
; i
<= MAX_RATIO
; i
++)
3265 XEXP (addr
, 1) = gen_int_mode (i
, Pmode
);
3266 if (memory_address_p (Pmode
, addr
))
3267 SET_BIT (valid_mult
, i
+ MAX_RATIO
);
3270 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3272 fprintf (dump_file
, " allowed multipliers:");
3273 for (i
= -MAX_RATIO
; i
<= MAX_RATIO
; i
++)
3274 if (TEST_BIT (valid_mult
, i
+ MAX_RATIO
))
3275 fprintf (dump_file
, " %d", (int) i
);
3276 fprintf (dump_file
, "\n");
3277 fprintf (dump_file
, "\n");
3281 if (ratio
> MAX_RATIO
|| ratio
< -MAX_RATIO
)
3284 return TEST_BIT (valid_mult
, ratio
+ MAX_RATIO
);
3287 /* Returns cost of address in shape symbol + var + OFFSET + RATIO * index.
3288 If SYMBOL_PRESENT is false, symbol is omitted. If VAR_PRESENT is false,
3289 variable is omitted. The created memory accesses MODE.
3291 TODO -- there must be some better way. This all is quite crude. */
3294 get_address_cost (bool symbol_present
, bool var_present
,
3295 unsigned HOST_WIDE_INT offset
, HOST_WIDE_INT ratio
)
3297 static bool initialized
= false;
3298 static HOST_WIDE_INT rat
, off
;
3299 static HOST_WIDE_INT min_offset
, max_offset
;
3300 static unsigned costs
[2][2][2][2];
3301 unsigned cost
, acost
;
3302 rtx seq
, addr
, base
;
3303 bool offset_p
, ratio_p
;
3305 HOST_WIDE_INT s_offset
;
3306 unsigned HOST_WIDE_INT mask
;
3314 reg1
= gen_raw_REG (Pmode
, LAST_VIRTUAL_REGISTER
+ 1);
3316 addr
= gen_rtx_fmt_ee (PLUS
, Pmode
, reg1
, NULL_RTX
);
3317 for (i
= 1; i
<= 1 << 20; i
<<= 1)
3319 XEXP (addr
, 1) = gen_int_mode (i
, Pmode
);
3320 if (!memory_address_p (Pmode
, addr
))
3323 max_offset
= i
>> 1;
3326 for (i
= 1; i
<= 1 << 20; i
<<= 1)
3328 XEXP (addr
, 1) = gen_int_mode (-i
, Pmode
);
3329 if (!memory_address_p (Pmode
, addr
))
3332 min_offset
= -(i
>> 1);
3334 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3336 fprintf (dump_file
, "get_address_cost:\n");
3337 fprintf (dump_file
, " min offset %d\n", (int) min_offset
);
3338 fprintf (dump_file
, " max offset %d\n", (int) max_offset
);
3342 for (i
= 2; i
<= MAX_RATIO
; i
++)
3343 if (multiplier_allowed_in_address_p (i
))
3350 bits
= GET_MODE_BITSIZE (Pmode
);
3351 mask
= ~(~(unsigned HOST_WIDE_INT
) 0 << (bits
- 1) << 1);
3353 if ((offset
>> (bits
- 1) & 1))
3358 offset_p
= (s_offset
!= 0
3359 && min_offset
<= s_offset
&& s_offset
<= max_offset
);
3360 ratio_p
= (ratio
!= 1
3361 && multiplier_allowed_in_address_p (ratio
));
3363 if (ratio
!= 1 && !ratio_p
)
3364 cost
+= multiply_by_cost (ratio
, Pmode
);
3366 if (s_offset
&& !offset_p
&& !symbol_present
)
3368 cost
+= add_cost (Pmode
);
3372 acost
= costs
[symbol_present
][var_present
][offset_p
][ratio_p
];
3377 addr
= gen_raw_REG (Pmode
, LAST_VIRTUAL_REGISTER
+ 1);
3378 reg1
= gen_raw_REG (Pmode
, LAST_VIRTUAL_REGISTER
+ 2);
3380 addr
= gen_rtx_fmt_ee (MULT
, Pmode
, addr
, gen_int_mode (rat
, Pmode
));
3383 addr
= gen_rtx_fmt_ee (PLUS
, Pmode
, addr
, reg1
);
3387 base
= gen_rtx_SYMBOL_REF (Pmode
, ggc_strdup (""));
3389 base
= gen_rtx_fmt_e (CONST
, Pmode
,
3390 gen_rtx_fmt_ee (PLUS
, Pmode
,
3392 gen_int_mode (off
, Pmode
)));
3395 base
= gen_int_mode (off
, Pmode
);
3400 addr
= gen_rtx_fmt_ee (PLUS
, Pmode
, addr
, base
);
3403 addr
= memory_address (Pmode
, addr
);
3407 acost
= seq_cost (seq
);
3408 acost
+= address_cost (addr
, Pmode
);
3412 costs
[symbol_present
][var_present
][offset_p
][ratio_p
] = acost
;
3415 return cost
+ acost
;
3417 /* Estimates cost of forcing EXPR into a variable. DEPENDS_ON is a set of the
3418 invariants the computation depends on. */
3421 force_var_cost (struct ivopts_data
*data
,
3422 tree expr
, bitmap
*depends_on
)
3424 static bool costs_initialized
= false;
3425 static unsigned integer_cost
;
3426 static unsigned symbol_cost
;
3427 static unsigned address_cost
;
3429 unsigned cost0
, cost1
, cost
;
3430 enum machine_mode mode
;
3432 if (!costs_initialized
)
3434 tree var
= create_tmp_var_raw (integer_type_node
, "test_var");
3435 rtx x
= gen_rtx_MEM (DECL_MODE (var
),
3436 gen_rtx_SYMBOL_REF (Pmode
, "test_var"));
3438 tree type
= build_pointer_type (integer_type_node
);
3440 integer_cost
= computation_cost (build_int_cst_type (integer_type_node
,
3443 SET_DECL_RTL (var
, x
);
3444 TREE_STATIC (var
) = 1;
3445 addr
= build1 (ADDR_EXPR
, type
, var
);
3446 symbol_cost
= computation_cost (addr
) + 1;
3449 = computation_cost (build2 (PLUS_EXPR
, type
,
3451 build_int_cst_type (type
, 2000))) + 1;
3452 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3454 fprintf (dump_file
, "force_var_cost:\n");
3455 fprintf (dump_file
, " integer %d\n", (int) integer_cost
);
3456 fprintf (dump_file
, " symbol %d\n", (int) symbol_cost
);
3457 fprintf (dump_file
, " address %d\n", (int) address_cost
);
3458 fprintf (dump_file
, " other %d\n", (int) target_spill_cost
);
3459 fprintf (dump_file
, "\n");
3462 costs_initialized
= true;
3469 fd_ivopts_data
= data
;
3470 walk_tree (&expr
, find_depends
, depends_on
, NULL
);
3473 if (SSA_VAR_P (expr
))
3476 if (TREE_INVARIANT (expr
))
3478 if (TREE_CODE (expr
) == INTEGER_CST
)
3479 return integer_cost
;
3481 if (TREE_CODE (expr
) == ADDR_EXPR
)
3483 tree obj
= TREE_OPERAND (expr
, 0);
3485 if (TREE_CODE (obj
) == VAR_DECL
3486 || TREE_CODE (obj
) == PARM_DECL
3487 || TREE_CODE (obj
) == RESULT_DECL
)
3491 return address_cost
;
3494 switch (TREE_CODE (expr
))
3499 op0
= TREE_OPERAND (expr
, 0);
3500 op1
= TREE_OPERAND (expr
, 1);
3504 if (is_gimple_val (op0
))
3507 cost0
= force_var_cost (data
, op0
, NULL
);
3509 if (is_gimple_val (op1
))
3512 cost1
= force_var_cost (data
, op1
, NULL
);
3517 /* Just an arbitrary value, FIXME. */
3518 return target_spill_cost
;
3521 mode
= TYPE_MODE (TREE_TYPE (expr
));
3522 switch (TREE_CODE (expr
))
3526 cost
= add_cost (mode
);
3530 if (cst_and_fits_in_hwi (op0
))
3531 cost
= multiply_by_cost (int_cst_value (op0
), mode
);
3532 else if (cst_and_fits_in_hwi (op1
))
3533 cost
= multiply_by_cost (int_cst_value (op1
), mode
);
3535 return target_spill_cost
;
3545 /* Bound the cost by target_spill_cost. The parts of complicated
3546 computations often are either loop invariant or at least can
3547 be shared between several iv uses, so letting this grow without
3548 limits would not give reasonable results. */
3549 return cost
< target_spill_cost
? cost
: target_spill_cost
;
3552 /* Estimates cost of expressing address ADDR as var + symbol + offset. The
3553 value of offset is added to OFFSET, SYMBOL_PRESENT and VAR_PRESENT are set
3554 to false if the corresponding part is missing. DEPENDS_ON is a set of the
3555 invariants the computation depends on. */
3558 split_address_cost (struct ivopts_data
*data
,
3559 tree addr
, bool *symbol_present
, bool *var_present
,
3560 unsigned HOST_WIDE_INT
*offset
, bitmap
*depends_on
)
3563 HOST_WIDE_INT bitsize
;
3564 HOST_WIDE_INT bitpos
;
3566 enum machine_mode mode
;
3567 int unsignedp
, volatilep
;
3569 core
= get_inner_reference (addr
, &bitsize
, &bitpos
, &toffset
, &mode
,
3570 &unsignedp
, &volatilep
, false);
3573 || bitpos
% BITS_PER_UNIT
!= 0
3574 || TREE_CODE (core
) != VAR_DECL
)
3576 *symbol_present
= false;
3577 *var_present
= true;
3578 fd_ivopts_data
= data
;
3579 walk_tree (&addr
, find_depends
, depends_on
, NULL
);
3580 return target_spill_cost
;
3583 *offset
+= bitpos
/ BITS_PER_UNIT
;
3584 if (TREE_STATIC (core
)
3585 || DECL_EXTERNAL (core
))
3587 *symbol_present
= true;
3588 *var_present
= false;
3592 *symbol_present
= false;
3593 *var_present
= true;
3597 /* Estimates cost of expressing difference of addresses E1 - E2 as
3598 var + symbol + offset. The value of offset is added to OFFSET,
3599 SYMBOL_PRESENT and VAR_PRESENT are set to false if the corresponding
3600 part is missing. DEPENDS_ON is a set of the invariants the computation
3604 ptr_difference_cost (struct ivopts_data
*data
,
3605 tree e1
, tree e2
, bool *symbol_present
, bool *var_present
,
3606 unsigned HOST_WIDE_INT
*offset
, bitmap
*depends_on
)
3608 HOST_WIDE_INT diff
= 0;
3611 gcc_assert (TREE_CODE (e1
) == ADDR_EXPR
);
3613 if (ptr_difference_const (e1
, e2
, &diff
))
3616 *symbol_present
= false;
3617 *var_present
= false;
3621 if (e2
== integer_zero_node
)
3622 return split_address_cost (data
, TREE_OPERAND (e1
, 0),
3623 symbol_present
, var_present
, offset
, depends_on
);
3625 *symbol_present
= false;
3626 *var_present
= true;
3628 cost
= force_var_cost (data
, e1
, depends_on
);
3629 cost
+= force_var_cost (data
, e2
, depends_on
);
3630 cost
+= add_cost (Pmode
);
3635 /* Estimates cost of expressing difference E1 - E2 as
3636 var + symbol + offset. The value of offset is added to OFFSET,
3637 SYMBOL_PRESENT and VAR_PRESENT are set to false if the corresponding
3638 part is missing. DEPENDS_ON is a set of the invariants the computation
3642 difference_cost (struct ivopts_data
*data
,
3643 tree e1
, tree e2
, bool *symbol_present
, bool *var_present
,
3644 unsigned HOST_WIDE_INT
*offset
, bitmap
*depends_on
)
3647 enum machine_mode mode
= TYPE_MODE (TREE_TYPE (e1
));
3648 unsigned HOST_WIDE_INT off1
, off2
;
3650 e1
= strip_offset (e1
, &off1
);
3651 e2
= strip_offset (e2
, &off2
);
3652 *offset
+= off1
- off2
;
3657 if (TREE_CODE (e1
) == ADDR_EXPR
)
3658 return ptr_difference_cost (data
, e1
, e2
, symbol_present
, var_present
, offset
,
3660 *symbol_present
= false;
3662 if (operand_equal_p (e1
, e2
, 0))
3664 *var_present
= false;
3667 *var_present
= true;
3669 return force_var_cost (data
, e1
, depends_on
);
3673 cost
= force_var_cost (data
, e2
, depends_on
);
3674 cost
+= multiply_by_cost (-1, mode
);
3679 cost
= force_var_cost (data
, e1
, depends_on
);
3680 cost
+= force_var_cost (data
, e2
, depends_on
);
3681 cost
+= add_cost (mode
);
3686 /* Determines the cost of the computation by that USE is expressed
3687 from induction variable CAND. If ADDRESS_P is true, we just need
3688 to create an address from it, otherwise we want to get it into
3689 register. A set of invariants we depend on is stored in
3690 DEPENDS_ON. AT is the statement at that the value is computed. */
3693 get_computation_cost_at (struct ivopts_data
*data
,
3694 struct iv_use
*use
, struct iv_cand
*cand
,
3695 bool address_p
, bitmap
*depends_on
, tree at
)
3697 tree ubase
= use
->iv
->base
, ustep
= use
->iv
->step
;
3699 tree utype
= TREE_TYPE (ubase
), ctype
;
3700 unsigned HOST_WIDE_INT ustepi
, cstepi
, offset
= 0;
3701 HOST_WIDE_INT ratio
, aratio
;
3702 bool var_present
, symbol_present
;
3703 unsigned cost
= 0, n_sums
;
3707 /* Only consider real candidates. */
3711 cbase
= cand
->iv
->base
;
3712 cstep
= cand
->iv
->step
;
3713 ctype
= TREE_TYPE (cbase
);
3715 if (TYPE_PRECISION (utype
) > TYPE_PRECISION (ctype
))
3717 /* We do not have a precision to express the values of use. */
3723 /* Do not try to express address of an object with computation based
3724 on address of a different object. This may cause problems in rtl
3725 level alias analysis (that does not expect this to be happening,
3726 as this is illegal in C), and would be unlikely to be useful
3728 if (use
->iv
->base_object
3729 && cand
->iv
->base_object
3730 && !operand_equal_p (use
->iv
->base_object
, cand
->iv
->base_object
, 0))
3734 if (TYPE_PRECISION (utype
) != TYPE_PRECISION (ctype
))
3736 /* TODO -- add direct handling of this case. */
3740 /* CSTEPI is removed from the offset in case statement is after the
3741 increment. If the step is not constant, we use zero instead.
3742 This is a bit imprecise (there is the extra addition), but
3743 redundancy elimination is likely to transform the code so that
3744 it uses value of the variable before increment anyway,
3745 so it is not that much unrealistic. */
3746 if (cst_and_fits_in_hwi (cstep
))
3747 cstepi
= int_cst_value (cstep
);
3751 if (cst_and_fits_in_hwi (ustep
)
3752 && cst_and_fits_in_hwi (cstep
))
3754 ustepi
= int_cst_value (ustep
);
3756 if (!divide (TYPE_PRECISION (utype
), ustepi
, cstepi
, &ratio
))
3763 rat
= constant_multiple_of (utype
, ustep
, cstep
);
3768 if (cst_and_fits_in_hwi (rat
))
3769 ratio
= int_cst_value (rat
);
3770 else if (integer_onep (rat
))
3772 else if (integer_all_onesp (rat
))
3778 /* use = ubase + ratio * (var - cbase). If either cbase is a constant
3779 or ratio == 1, it is better to handle this like
3781 ubase - ratio * cbase + ratio * var
3783 (also holds in the case ratio == -1, TODO. */
3785 if (cst_and_fits_in_hwi (cbase
))
3787 offset
= - ratio
* int_cst_value (cbase
);
3788 cost
+= difference_cost (data
,
3789 ubase
, integer_zero_node
,
3790 &symbol_present
, &var_present
, &offset
,
3793 else if (ratio
== 1)
3795 cost
+= difference_cost (data
,
3797 &symbol_present
, &var_present
, &offset
,
3802 cost
+= force_var_cost (data
, cbase
, depends_on
);
3803 cost
+= add_cost (TYPE_MODE (ctype
));
3804 cost
+= difference_cost (data
,
3805 ubase
, integer_zero_node
,
3806 &symbol_present
, &var_present
, &offset
,
3810 /* If we are after the increment, the value of the candidate is higher by
3812 if (stmt_after_increment (data
->current_loop
, cand
, at
))
3813 offset
-= ratio
* cstepi
;
3815 /* Now the computation is in shape symbol + var1 + const + ratio * var2.
3816 (symbol/var/const parts may be omitted). If we are looking for an address,
3817 find the cost of addressing this. */
3819 return cost
+ get_address_cost (symbol_present
, var_present
, offset
, ratio
);
3821 /* Otherwise estimate the costs for computing the expression. */
3822 aratio
= ratio
> 0 ? ratio
: -ratio
;
3823 if (!symbol_present
&& !var_present
&& !offset
)
3826 cost
+= multiply_by_cost (ratio
, TYPE_MODE (ctype
));
3832 cost
+= multiply_by_cost (aratio
, TYPE_MODE (ctype
));
3836 /* Symbol + offset should be compile-time computable. */
3837 && (symbol_present
|| offset
))
3840 return cost
+ n_sums
* add_cost (TYPE_MODE (ctype
));
3844 /* Just get the expression, expand it and measure the cost. */
3845 tree comp
= get_computation_at (data
->current_loop
, use
, cand
, at
);
3851 comp
= build1 (INDIRECT_REF
, TREE_TYPE (TREE_TYPE (comp
)), comp
);
3853 return computation_cost (comp
);
3857 /* Determines the cost of the computation by that USE is expressed
3858 from induction variable CAND. If ADDRESS_P is true, we just need
3859 to create an address from it, otherwise we want to get it into
3860 register. A set of invariants we depend on is stored in
3864 get_computation_cost (struct ivopts_data
*data
,
3865 struct iv_use
*use
, struct iv_cand
*cand
,
3866 bool address_p
, bitmap
*depends_on
)
3868 return get_computation_cost_at (data
,
3869 use
, cand
, address_p
, depends_on
, use
->stmt
);
3872 /* Determines cost of basing replacement of USE on CAND in a generic
3876 determine_use_iv_cost_generic (struct ivopts_data
*data
,
3877 struct iv_use
*use
, struct iv_cand
*cand
)
3882 /* The simple case first -- if we need to express value of the preserved
3883 original biv, the cost is 0. This also prevents us from counting the
3884 cost of increment twice -- once at this use and once in the cost of
3886 if (cand
->pos
== IP_ORIGINAL
3887 && cand
->incremented_at
== use
->stmt
)
3889 set_use_iv_cost (data
, use
, cand
, 0, NULL
, NULL_TREE
);
3893 cost
= get_computation_cost (data
, use
, cand
, false, &depends_on
);
3894 set_use_iv_cost (data
, use
, cand
, cost
, depends_on
, NULL_TREE
);
3896 return cost
!= INFTY
;
3899 /* Determines cost of basing replacement of USE on CAND in an address. */
3902 determine_use_iv_cost_address (struct ivopts_data
*data
,
3903 struct iv_use
*use
, struct iv_cand
*cand
)
3906 unsigned cost
= get_computation_cost (data
, use
, cand
, true, &depends_on
);
3908 set_use_iv_cost (data
, use
, cand
, cost
, depends_on
, NULL_TREE
);
3910 return cost
!= INFTY
;
3913 /* Computes value of induction variable IV in iteration NITER. */
3916 iv_value (struct iv
*iv
, tree niter
)
3919 tree type
= TREE_TYPE (iv
->base
);
3921 niter
= fold_convert (type
, niter
);
3922 val
= fold_build2 (MULT_EXPR
, type
, iv
->step
, niter
);
3924 return fold_build2 (PLUS_EXPR
, type
, iv
->base
, val
);
3927 /* Computes value of candidate CAND at position AT in iteration NITER. */
3930 cand_value_at (struct loop
*loop
, struct iv_cand
*cand
, tree at
, tree niter
)
3932 tree val
= iv_value (cand
->iv
, niter
);
3933 tree type
= TREE_TYPE (cand
->iv
->base
);
3935 if (stmt_after_increment (loop
, cand
, at
))
3936 val
= fold_build2 (PLUS_EXPR
, type
, val
, cand
->iv
->step
);
3941 /* Returns period of induction variable iv. */
3944 iv_period (struct iv
*iv
)
3946 tree step
= iv
->step
, period
, type
;
3949 gcc_assert (step
&& TREE_CODE (step
) == INTEGER_CST
);
3951 /* Period of the iv is gcd (step, type range). Since type range is power
3952 of two, it suffices to determine the maximum power of two that divides
3954 pow2div
= num_ending_zeros (step
);
3955 type
= unsigned_type_for (TREE_TYPE (step
));
3957 period
= build_low_bits_mask (type
,
3958 (TYPE_PRECISION (type
)
3959 - tree_low_cst (pow2div
, 1)));
3964 /* Returns the comparison operator used when eliminating the iv USE. */
3966 static enum tree_code
3967 iv_elimination_compare (struct ivopts_data
*data
, struct iv_use
*use
)
3969 struct loop
*loop
= data
->current_loop
;
3973 ex_bb
= bb_for_stmt (use
->stmt
);
3974 exit
= EDGE_SUCC (ex_bb
, 0);
3975 if (flow_bb_inside_loop_p (loop
, exit
->dest
))
3976 exit
= EDGE_SUCC (ex_bb
, 1);
3978 return (exit
->flags
& EDGE_TRUE_VALUE
? EQ_EXPR
: NE_EXPR
);
3981 /* Check whether it is possible to express the condition in USE by comparison
3982 of candidate CAND. If so, store the value compared with to BOUND. */
3985 may_eliminate_iv (struct ivopts_data
*data
,
3986 struct iv_use
*use
, struct iv_cand
*cand
, tree
*bound
)
3990 struct tree_niter_desc
*niter
;
3992 tree wider_type
, period
, per_type
;
3993 struct loop
*loop
= data
->current_loop
;
3995 if (TREE_CODE (cand
->iv
->step
) != INTEGER_CST
)
3998 /* For now works only for exits that dominate the loop latch. TODO -- extend
3999 for other conditions inside loop body. */
4000 ex_bb
= bb_for_stmt (use
->stmt
);
4001 if (use
->stmt
!= last_stmt (ex_bb
)
4002 || TREE_CODE (use
->stmt
) != COND_EXPR
)
4004 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, ex_bb
))
4007 exit
= EDGE_SUCC (ex_bb
, 0);
4008 if (flow_bb_inside_loop_p (loop
, exit
->dest
))
4009 exit
= EDGE_SUCC (ex_bb
, 1);
4010 if (flow_bb_inside_loop_p (loop
, exit
->dest
))
4013 niter
= niter_for_exit (data
, exit
);
4015 || !zero_p (niter
->may_be_zero
))
4019 nit_type
= TREE_TYPE (nit
);
4021 /* Determine whether we may use the variable to test whether niter iterations
4022 elapsed. This is the case iff the period of the induction variable is
4023 greater than the number of iterations. */
4024 period
= iv_period (cand
->iv
);
4027 per_type
= TREE_TYPE (period
);
4029 wider_type
= TREE_TYPE (period
);
4030 if (TYPE_PRECISION (nit_type
) < TYPE_PRECISION (per_type
))
4031 wider_type
= per_type
;
4033 wider_type
= nit_type
;
4035 if (!integer_nonzerop (fold_build2 (GE_EXPR
, boolean_type_node
,
4036 fold_convert (wider_type
, period
),
4037 fold_convert (wider_type
, nit
))))
4040 *bound
= cand_value_at (loop
, cand
, use
->stmt
, nit
);
4044 /* Determines cost of basing replacement of USE on CAND in a condition. */
4047 determine_use_iv_cost_condition (struct ivopts_data
*data
,
4048 struct iv_use
*use
, struct iv_cand
*cand
)
4050 tree bound
= NULL_TREE
, op
, cond
;
4051 bitmap depends_on
= NULL
;
4054 /* Only consider real candidates. */
4057 set_use_iv_cost (data
, use
, cand
, INFTY
, NULL
, NULL_TREE
);
4061 if (may_eliminate_iv (data
, use
, cand
, &bound
))
4063 cost
= force_var_cost (data
, bound
, &depends_on
);
4065 set_use_iv_cost (data
, use
, cand
, cost
, depends_on
, bound
);
4066 return cost
!= INFTY
;
4069 /* The induction variable elimination failed; just express the original
4070 giv. If it is compared with an invariant, note that we cannot get
4072 cost
= get_computation_cost (data
, use
, cand
, false, &depends_on
);
4075 if (TREE_CODE (cond
) != SSA_NAME
)
4077 op
= TREE_OPERAND (cond
, 0);
4078 if (TREE_CODE (op
) == SSA_NAME
&& !zero_p (get_iv (data
, op
)->step
))
4079 op
= TREE_OPERAND (cond
, 1);
4080 if (TREE_CODE (op
) == SSA_NAME
)
4082 op
= get_iv (data
, op
)->base
;
4083 fd_ivopts_data
= data
;
4084 walk_tree (&op
, find_depends
, &depends_on
, NULL
);
4088 set_use_iv_cost (data
, use
, cand
, cost
, depends_on
, NULL
);
4089 return cost
!= INFTY
;
4092 /* Checks whether it is possible to replace the final value of USE by
4093 a direct computation. If so, the formula is stored to *VALUE. */
4096 may_replace_final_value (struct ivopts_data
*data
, struct iv_use
*use
,
4099 struct loop
*loop
= data
->current_loop
;
4101 struct tree_niter_desc
*niter
;
4103 exit
= single_dom_exit (loop
);
4107 gcc_assert (dominated_by_p (CDI_DOMINATORS
, exit
->src
,
4108 bb_for_stmt (use
->stmt
)));
4110 niter
= niter_for_single_dom_exit (data
);
4112 || !zero_p (niter
->may_be_zero
))
4115 *value
= iv_value (use
->iv
, niter
->niter
);
4120 /* Determines cost of replacing final value of USE using CAND. */
4123 determine_use_iv_cost_outer (struct ivopts_data
*data
,
4124 struct iv_use
*use
, struct iv_cand
*cand
)
4129 tree value
= NULL_TREE
;
4130 struct loop
*loop
= data
->current_loop
;
4132 /* The simple case first -- if we need to express value of the preserved
4133 original biv, the cost is 0. This also prevents us from counting the
4134 cost of increment twice -- once at this use and once in the cost of
4136 if (cand
->pos
== IP_ORIGINAL
4137 && cand
->incremented_at
== use
->stmt
)
4139 set_use_iv_cost (data
, use
, cand
, 0, NULL
, NULL_TREE
);
4145 if (!may_replace_final_value (data
, use
, &value
))
4147 set_use_iv_cost (data
, use
, cand
, INFTY
, NULL
, NULL_TREE
);
4152 cost
= force_var_cost (data
, value
, &depends_on
);
4154 cost
/= AVG_LOOP_NITER (loop
);
4156 set_use_iv_cost (data
, use
, cand
, cost
, depends_on
, value
);
4157 return cost
!= INFTY
;
4160 exit
= single_dom_exit (loop
);
4163 /* If there is just a single exit, we may use value of the candidate
4164 after we take it to determine the value of use. */
4165 cost
= get_computation_cost_at (data
, use
, cand
, false, &depends_on
,
4166 last_stmt (exit
->src
));
4168 cost
/= AVG_LOOP_NITER (loop
);
4172 /* Otherwise we just need to compute the iv. */
4173 cost
= get_computation_cost (data
, use
, cand
, false, &depends_on
);
4176 set_use_iv_cost (data
, use
, cand
, cost
, depends_on
, NULL_TREE
);
4178 return cost
!= INFTY
;
4181 /* Determines cost of basing replacement of USE on CAND. Returns false
4182 if USE cannot be based on CAND. */
4185 determine_use_iv_cost (struct ivopts_data
*data
,
4186 struct iv_use
*use
, struct iv_cand
*cand
)
4190 case USE_NONLINEAR_EXPR
:
4191 return determine_use_iv_cost_generic (data
, use
, cand
);
4194 return determine_use_iv_cost_outer (data
, use
, cand
);
4197 return determine_use_iv_cost_address (data
, use
, cand
);
4200 return determine_use_iv_cost_condition (data
, use
, cand
);
4207 /* Determines costs of basing the use of the iv on an iv candidate. */
4210 determine_use_iv_costs (struct ivopts_data
*data
)
4214 struct iv_cand
*cand
;
4215 bitmap to_clear
= BITMAP_ALLOC (NULL
);
4217 alloc_use_cost_map (data
);
4219 for (i
= 0; i
< n_iv_uses (data
); i
++)
4221 use
= iv_use (data
, i
);
4223 if (data
->consider_all_candidates
)
4225 for (j
= 0; j
< n_iv_cands (data
); j
++)
4227 cand
= iv_cand (data
, j
);
4228 determine_use_iv_cost (data
, use
, cand
);
4235 EXECUTE_IF_SET_IN_BITMAP (use
->related_cands
, 0, j
, bi
)
4237 cand
= iv_cand (data
, j
);
4238 if (!determine_use_iv_cost (data
, use
, cand
))
4239 bitmap_set_bit (to_clear
, j
);
4242 /* Remove the candidates for that the cost is infinite from
4243 the list of related candidates. */
4244 bitmap_and_compl_into (use
->related_cands
, to_clear
);
4245 bitmap_clear (to_clear
);
4249 BITMAP_FREE (to_clear
);
4251 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4253 fprintf (dump_file
, "Use-candidate costs:\n");
4255 for (i
= 0; i
< n_iv_uses (data
); i
++)
4257 use
= iv_use (data
, i
);
4259 fprintf (dump_file
, "Use %d:\n", i
);
4260 fprintf (dump_file
, " cand\tcost\tdepends on\n");
4261 for (j
= 0; j
< use
->n_map_members
; j
++)
4263 if (!use
->cost_map
[j
].cand
4264 || use
->cost_map
[j
].cost
== INFTY
)
4267 fprintf (dump_file
, " %d\t%d\t",
4268 use
->cost_map
[j
].cand
->id
,
4269 use
->cost_map
[j
].cost
);
4270 if (use
->cost_map
[j
].depends_on
)
4271 bitmap_print (dump_file
,
4272 use
->cost_map
[j
].depends_on
, "","");
4273 fprintf (dump_file
, "\n");
4276 fprintf (dump_file
, "\n");
4278 fprintf (dump_file
, "\n");
4282 /* Determines cost of the candidate CAND. */
4285 determine_iv_cost (struct ivopts_data
*data
, struct iv_cand
*cand
)
4287 unsigned cost_base
, cost_step
;
4296 /* There are two costs associated with the candidate -- its increment
4297 and its initialization. The second is almost negligible for any loop
4298 that rolls enough, so we take it just very little into account. */
4300 base
= cand
->iv
->base
;
4301 cost_base
= force_var_cost (data
, base
, NULL
);
4302 cost_step
= add_cost (TYPE_MODE (TREE_TYPE (base
)));
4304 cand
->cost
= cost_step
+ cost_base
/ AVG_LOOP_NITER (current_loop
);
4306 /* Prefer the original iv unless we may gain something by replacing it;
4307 this is not really relevant for artificial ivs created by other
4309 if (cand
->pos
== IP_ORIGINAL
4310 && !DECL_ARTIFICIAL (SSA_NAME_VAR (cand
->var_before
)))
4313 /* Prefer not to insert statements into latch unless there are some
4314 already (so that we do not create unnecessary jumps). */
4315 if (cand
->pos
== IP_END
4316 && empty_block_p (ip_end_pos (data
->current_loop
)))
4320 /* Determines costs of computation of the candidates. */
4323 determine_iv_costs (struct ivopts_data
*data
)
4327 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4329 fprintf (dump_file
, "Candidate costs:\n");
4330 fprintf (dump_file
, " cand\tcost\n");
4333 for (i
= 0; i
< n_iv_cands (data
); i
++)
4335 struct iv_cand
*cand
= iv_cand (data
, i
);
4337 determine_iv_cost (data
, cand
);
4339 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4340 fprintf (dump_file
, " %d\t%d\n", i
, cand
->cost
);
4343 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4344 fprintf (dump_file
, "\n");
4347 /* Calculates cost for having SIZE induction variables. */
4350 ivopts_global_cost_for_size (struct ivopts_data
*data
, unsigned size
)
4352 return global_cost_for_size (size
,
4353 loop_data (data
->current_loop
)->regs_used
,
4357 /* For each size of the induction variable set determine the penalty. */
4360 determine_set_costs (struct ivopts_data
*data
)
4364 struct loop
*loop
= data
->current_loop
;
4367 /* We use the following model (definitely improvable, especially the
4368 cost function -- TODO):
4370 We estimate the number of registers available (using MD data), name it A.
4372 We estimate the number of registers used by the loop, name it U. This
4373 number is obtained as the number of loop phi nodes (not counting virtual
4374 registers and bivs) + the number of variables from outside of the loop.
4376 We set a reserve R (free regs that are used for temporary computations,
4377 etc.). For now the reserve is a constant 3.
4379 Let I be the number of induction variables.
4381 -- if U + I + R <= A, the cost is I * SMALL_COST (just not to encourage
4382 make a lot of ivs without a reason).
4383 -- if A - R < U + I <= A, the cost is I * PRES_COST
4384 -- if U + I > A, the cost is I * PRES_COST and
4385 number of uses * SPILL_COST * (U + I - A) / (U + I) is added. */
4387 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4389 fprintf (dump_file
, "Global costs:\n");
4390 fprintf (dump_file
, " target_avail_regs %d\n", target_avail_regs
);
4391 fprintf (dump_file
, " target_small_cost %d\n", target_small_cost
);
4392 fprintf (dump_file
, " target_pres_cost %d\n", target_pres_cost
);
4393 fprintf (dump_file
, " target_spill_cost %d\n", target_spill_cost
);
4397 for (phi
= phi_nodes (loop
->header
); phi
; phi
= PHI_CHAIN (phi
))
4399 op
= PHI_RESULT (phi
);
4401 if (!is_gimple_reg (op
))
4404 if (get_iv (data
, op
))
4410 EXECUTE_IF_SET_IN_BITMAP (data
->relevant
, 0, j
, bi
)
4412 struct version_info
*info
= ver_info (data
, j
);
4414 if (info
->inv_id
&& info
->has_nonlin_use
)
4418 loop_data (loop
)->regs_used
= n
;
4419 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4420 fprintf (dump_file
, " regs_used %d\n", n
);
4422 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4424 fprintf (dump_file
, " cost for size:\n");
4425 fprintf (dump_file
, " ivs\tcost\n");
4426 for (j
= 0; j
<= 2 * target_avail_regs
; j
++)
4427 fprintf (dump_file
, " %d\t%d\n", j
,
4428 ivopts_global_cost_for_size (data
, j
));
4429 fprintf (dump_file
, "\n");
4433 /* Returns true if A is a cheaper cost pair than B. */
4436 cheaper_cost_pair (struct cost_pair
*a
, struct cost_pair
*b
)
4444 if (a
->cost
< b
->cost
)
4447 if (a
->cost
> b
->cost
)
4450 /* In case the costs are the same, prefer the cheaper candidate. */
4451 if (a
->cand
->cost
< b
->cand
->cost
)
4457 /* Computes the cost field of IVS structure. */
4460 iv_ca_recount_cost (struct ivopts_data
*data
, struct iv_ca
*ivs
)
4464 cost
+= ivs
->cand_use_cost
;
4465 cost
+= ivs
->cand_cost
;
4466 cost
+= ivopts_global_cost_for_size (data
, ivs
->n_regs
);
4471 /* Remove invariants in set INVS to set IVS. */
4474 iv_ca_set_remove_invariants (struct iv_ca
*ivs
, bitmap invs
)
4482 EXECUTE_IF_SET_IN_BITMAP (invs
, 0, iid
, bi
)
4484 ivs
->n_invariant_uses
[iid
]--;
4485 if (ivs
->n_invariant_uses
[iid
] == 0)
4490 /* Set USE not to be expressed by any candidate in IVS. */
4493 iv_ca_set_no_cp (struct ivopts_data
*data
, struct iv_ca
*ivs
,
4496 unsigned uid
= use
->id
, cid
;
4497 struct cost_pair
*cp
;
4499 cp
= ivs
->cand_for_use
[uid
];
4505 ivs
->cand_for_use
[uid
] = NULL
;
4506 ivs
->n_cand_uses
[cid
]--;
4508 if (ivs
->n_cand_uses
[cid
] == 0)
4510 bitmap_clear_bit (ivs
->cands
, cid
);
4511 /* Do not count the pseudocandidates. */
4515 ivs
->cand_cost
-= cp
->cand
->cost
;
4517 iv_ca_set_remove_invariants (ivs
, cp
->cand
->depends_on
);
4520 ivs
->cand_use_cost
-= cp
->cost
;
4522 iv_ca_set_remove_invariants (ivs
, cp
->depends_on
);
4523 iv_ca_recount_cost (data
, ivs
);
4526 /* Add invariants in set INVS to set IVS. */
4529 iv_ca_set_add_invariants (struct iv_ca
*ivs
, bitmap invs
)
4537 EXECUTE_IF_SET_IN_BITMAP (invs
, 0, iid
, bi
)
4539 ivs
->n_invariant_uses
[iid
]++;
4540 if (ivs
->n_invariant_uses
[iid
] == 1)
4545 /* Set cost pair for USE in set IVS to CP. */
4548 iv_ca_set_cp (struct ivopts_data
*data
, struct iv_ca
*ivs
,
4549 struct iv_use
*use
, struct cost_pair
*cp
)
4551 unsigned uid
= use
->id
, cid
;
4553 if (ivs
->cand_for_use
[uid
] == cp
)
4556 if (ivs
->cand_for_use
[uid
])
4557 iv_ca_set_no_cp (data
, ivs
, use
);
4564 ivs
->cand_for_use
[uid
] = cp
;
4565 ivs
->n_cand_uses
[cid
]++;
4566 if (ivs
->n_cand_uses
[cid
] == 1)
4568 bitmap_set_bit (ivs
->cands
, cid
);
4569 /* Do not count the pseudocandidates. */
4573 ivs
->cand_cost
+= cp
->cand
->cost
;
4575 iv_ca_set_add_invariants (ivs
, cp
->cand
->depends_on
);
4578 ivs
->cand_use_cost
+= cp
->cost
;
4579 iv_ca_set_add_invariants (ivs
, cp
->depends_on
);
4580 iv_ca_recount_cost (data
, ivs
);
4584 /* Extend set IVS by expressing USE by some of the candidates in it
4588 iv_ca_add_use (struct ivopts_data
*data
, struct iv_ca
*ivs
,
4591 struct cost_pair
*best_cp
= NULL
, *cp
;
4595 gcc_assert (ivs
->upto
>= use
->id
);
4597 if (ivs
->upto
== use
->id
)
4603 EXECUTE_IF_SET_IN_BITMAP (ivs
->cands
, 0, i
, bi
)
4605 cp
= get_use_iv_cost (data
, use
, iv_cand (data
, i
));
4607 if (cheaper_cost_pair (cp
, best_cp
))
4611 iv_ca_set_cp (data
, ivs
, use
, best_cp
);
4614 /* Get cost for assignment IVS. */
4617 iv_ca_cost (struct iv_ca
*ivs
)
4619 return (ivs
->bad_uses
? INFTY
: ivs
->cost
);
4622 /* Returns true if all dependences of CP are among invariants in IVS. */
4625 iv_ca_has_deps (struct iv_ca
*ivs
, struct cost_pair
*cp
)
4630 if (!cp
->depends_on
)
4633 EXECUTE_IF_SET_IN_BITMAP (cp
->depends_on
, 0, i
, bi
)
4635 if (ivs
->n_invariant_uses
[i
] == 0)
4642 /* Creates change of expressing USE by NEW_CP instead of OLD_CP and chains
4643 it before NEXT_CHANGE. */
4645 static struct iv_ca_delta
*
4646 iv_ca_delta_add (struct iv_use
*use
, struct cost_pair
*old_cp
,
4647 struct cost_pair
*new_cp
, struct iv_ca_delta
*next_change
)
4649 struct iv_ca_delta
*change
= xmalloc (sizeof (struct iv_ca_delta
));
4652 change
->old_cp
= old_cp
;
4653 change
->new_cp
= new_cp
;
4654 change
->next_change
= next_change
;
4659 /* Joins two lists of changes L1 and L2. Destructive -- old lists
4662 static struct iv_ca_delta
*
4663 iv_ca_delta_join (struct iv_ca_delta
*l1
, struct iv_ca_delta
*l2
)
4665 struct iv_ca_delta
*last
;
4673 for (last
= l1
; last
->next_change
; last
= last
->next_change
)
4675 last
->next_change
= l2
;
4680 /* Returns candidate by that USE is expressed in IVS. */
4682 static struct cost_pair
*
4683 iv_ca_cand_for_use (struct iv_ca
*ivs
, struct iv_use
*use
)
4685 return ivs
->cand_for_use
[use
->id
];
4688 /* Reverse the list of changes DELTA, forming the inverse to it. */
4690 static struct iv_ca_delta
*
4691 iv_ca_delta_reverse (struct iv_ca_delta
*delta
)
4693 struct iv_ca_delta
*act
, *next
, *prev
= NULL
;
4694 struct cost_pair
*tmp
;
4696 for (act
= delta
; act
; act
= next
)
4698 next
= act
->next_change
;
4699 act
->next_change
= prev
;
4703 act
->old_cp
= act
->new_cp
;
4710 /* Commit changes in DELTA to IVS. If FORWARD is false, the changes are
4711 reverted instead. */
4714 iv_ca_delta_commit (struct ivopts_data
*data
, struct iv_ca
*ivs
,
4715 struct iv_ca_delta
*delta
, bool forward
)
4717 struct cost_pair
*from
, *to
;
4718 struct iv_ca_delta
*act
;
4721 delta
= iv_ca_delta_reverse (delta
);
4723 for (act
= delta
; act
; act
= act
->next_change
)
4727 gcc_assert (iv_ca_cand_for_use (ivs
, act
->use
) == from
);
4728 iv_ca_set_cp (data
, ivs
, act
->use
, to
);
4732 iv_ca_delta_reverse (delta
);
4735 /* Returns true if CAND is used in IVS. */
4738 iv_ca_cand_used_p (struct iv_ca
*ivs
, struct iv_cand
*cand
)
4740 return ivs
->n_cand_uses
[cand
->id
] > 0;
4743 /* Returns number of induction variable candidates in the set IVS. */
4746 iv_ca_n_cands (struct iv_ca
*ivs
)
4748 return ivs
->n_cands
;
4751 /* Free the list of changes DELTA. */
4754 iv_ca_delta_free (struct iv_ca_delta
**delta
)
4756 struct iv_ca_delta
*act
, *next
;
4758 for (act
= *delta
; act
; act
= next
)
4760 next
= act
->next_change
;
4767 /* Allocates new iv candidates assignment. */
4769 static struct iv_ca
*
4770 iv_ca_new (struct ivopts_data
*data
)
4772 struct iv_ca
*nw
= xmalloc (sizeof (struct iv_ca
));
4776 nw
->cand_for_use
= xcalloc (n_iv_uses (data
), sizeof (struct cost_pair
*));
4777 nw
->n_cand_uses
= xcalloc (n_iv_cands (data
), sizeof (unsigned));
4778 nw
->cands
= BITMAP_ALLOC (NULL
);
4781 nw
->cand_use_cost
= 0;
4783 nw
->n_invariant_uses
= xcalloc (data
->max_inv_id
+ 1, sizeof (unsigned));
4789 /* Free memory occupied by the set IVS. */
4792 iv_ca_free (struct iv_ca
**ivs
)
4794 free ((*ivs
)->cand_for_use
);
4795 free ((*ivs
)->n_cand_uses
);
4796 BITMAP_FREE ((*ivs
)->cands
);
4797 free ((*ivs
)->n_invariant_uses
);
4802 /* Dumps IVS to FILE. */
4805 iv_ca_dump (struct ivopts_data
*data
, FILE *file
, struct iv_ca
*ivs
)
4807 const char *pref
= " invariants ";
4810 fprintf (file
, " cost %d\n", iv_ca_cost (ivs
));
4811 bitmap_print (file
, ivs
->cands
, " candidates ","\n");
4813 for (i
= 1; i
<= data
->max_inv_id
; i
++)
4814 if (ivs
->n_invariant_uses
[i
])
4816 fprintf (file
, "%s%d", pref
, i
);
4819 fprintf (file
, "\n");
4822 /* Try changing candidate in IVS to CAND for each use. Return cost of the
4823 new set, and store differences in DELTA. Number of induction variables
4824 in the new set is stored to N_IVS. */
4827 iv_ca_extend (struct ivopts_data
*data
, struct iv_ca
*ivs
,
4828 struct iv_cand
*cand
, struct iv_ca_delta
**delta
,
4833 struct cost_pair
*old_cp
, *new_cp
;
4836 for (i
= 0; i
< ivs
->upto
; i
++)
4838 use
= iv_use (data
, i
);
4839 old_cp
= iv_ca_cand_for_use (ivs
, use
);
4842 && old_cp
->cand
== cand
)
4845 new_cp
= get_use_iv_cost (data
, use
, cand
);
4849 if (!iv_ca_has_deps (ivs
, new_cp
))
4852 if (!cheaper_cost_pair (new_cp
, old_cp
))
4855 *delta
= iv_ca_delta_add (use
, old_cp
, new_cp
, *delta
);
4858 iv_ca_delta_commit (data
, ivs
, *delta
, true);
4859 cost
= iv_ca_cost (ivs
);
4861 *n_ivs
= iv_ca_n_cands (ivs
);
4862 iv_ca_delta_commit (data
, ivs
, *delta
, false);
4867 /* Try narrowing set IVS by removing CAND. Return the cost of
4868 the new set and store the differences in DELTA. */
4871 iv_ca_narrow (struct ivopts_data
*data
, struct iv_ca
*ivs
,
4872 struct iv_cand
*cand
, struct iv_ca_delta
**delta
)
4876 struct cost_pair
*old_cp
, *new_cp
, *cp
;
4878 struct iv_cand
*cnd
;
4882 for (i
= 0; i
< n_iv_uses (data
); i
++)
4884 use
= iv_use (data
, i
);
4886 old_cp
= iv_ca_cand_for_use (ivs
, use
);
4887 if (old_cp
->cand
!= cand
)
4892 if (data
->consider_all_candidates
)
4894 EXECUTE_IF_SET_IN_BITMAP (ivs
->cands
, 0, ci
, bi
)
4899 cnd
= iv_cand (data
, ci
);
4901 cp
= get_use_iv_cost (data
, use
, cnd
);
4904 if (!iv_ca_has_deps (ivs
, cp
))
4907 if (!cheaper_cost_pair (cp
, new_cp
))
4915 EXECUTE_IF_AND_IN_BITMAP (use
->related_cands
, ivs
->cands
, 0, ci
, bi
)
4920 cnd
= iv_cand (data
, ci
);
4922 cp
= get_use_iv_cost (data
, use
, cnd
);
4925 if (!iv_ca_has_deps (ivs
, cp
))
4928 if (!cheaper_cost_pair (cp
, new_cp
))
4937 iv_ca_delta_free (delta
);
4941 *delta
= iv_ca_delta_add (use
, old_cp
, new_cp
, *delta
);
4944 iv_ca_delta_commit (data
, ivs
, *delta
, true);
4945 cost
= iv_ca_cost (ivs
);
4946 iv_ca_delta_commit (data
, ivs
, *delta
, false);
4951 /* Try optimizing the set of candidates IVS by removing candidates different
4952 from to EXCEPT_CAND from it. Return cost of the new set, and store
4953 differences in DELTA. */
4956 iv_ca_prune (struct ivopts_data
*data
, struct iv_ca
*ivs
,
4957 struct iv_cand
*except_cand
, struct iv_ca_delta
**delta
)
4960 struct iv_ca_delta
*act_delta
, *best_delta
;
4961 unsigned i
, best_cost
, acost
;
4962 struct iv_cand
*cand
;
4965 best_cost
= iv_ca_cost (ivs
);
4967 EXECUTE_IF_SET_IN_BITMAP (ivs
->cands
, 0, i
, bi
)
4969 cand
= iv_cand (data
, i
);
4971 if (cand
== except_cand
)
4974 acost
= iv_ca_narrow (data
, ivs
, cand
, &act_delta
);
4976 if (acost
< best_cost
)
4979 iv_ca_delta_free (&best_delta
);
4980 best_delta
= act_delta
;
4983 iv_ca_delta_free (&act_delta
);
4992 /* Recurse to possibly remove other unnecessary ivs. */
4993 iv_ca_delta_commit (data
, ivs
, best_delta
, true);
4994 best_cost
= iv_ca_prune (data
, ivs
, except_cand
, delta
);
4995 iv_ca_delta_commit (data
, ivs
, best_delta
, false);
4996 *delta
= iv_ca_delta_join (best_delta
, *delta
);
5000 /* Tries to extend the sets IVS in the best possible way in order
5001 to express the USE. */
5004 try_add_cand_for (struct ivopts_data
*data
, struct iv_ca
*ivs
,
5007 unsigned best_cost
, act_cost
;
5010 struct iv_cand
*cand
;
5011 struct iv_ca_delta
*best_delta
= NULL
, *act_delta
;
5012 struct cost_pair
*cp
;
5014 iv_ca_add_use (data
, ivs
, use
);
5015 best_cost
= iv_ca_cost (ivs
);
5017 cp
= iv_ca_cand_for_use (ivs
, use
);
5020 best_delta
= iv_ca_delta_add (use
, NULL
, cp
, NULL
);
5021 iv_ca_set_no_cp (data
, ivs
, use
);
5024 /* First try important candidates. Only if it fails, try the specific ones.
5025 Rationale -- in loops with many variables the best choice often is to use
5026 just one generic biv. If we added here many ivs specific to the uses,
5027 the optimization algorithm later would be likely to get stuck in a local
5028 minimum, thus causing us to create too many ivs. The approach from
5029 few ivs to more seems more likely to be successful -- starting from few
5030 ivs, replacing an expensive use by a specific iv should always be a
5032 EXECUTE_IF_SET_IN_BITMAP (data
->important_candidates
, 0, i
, bi
)
5034 cand
= iv_cand (data
, i
);
5036 if (iv_ca_cand_used_p (ivs
, cand
))
5039 cp
= get_use_iv_cost (data
, use
, cand
);
5043 iv_ca_set_cp (data
, ivs
, use
, cp
);
5044 act_cost
= iv_ca_extend (data
, ivs
, cand
, &act_delta
, NULL
);
5045 iv_ca_set_no_cp (data
, ivs
, use
);
5046 act_delta
= iv_ca_delta_add (use
, NULL
, cp
, act_delta
);
5048 if (act_cost
< best_cost
)
5050 best_cost
= act_cost
;
5052 iv_ca_delta_free (&best_delta
);
5053 best_delta
= act_delta
;
5056 iv_ca_delta_free (&act_delta
);
5059 if (best_cost
== INFTY
)
5061 for (i
= 0; i
< use
->n_map_members
; i
++)
5063 cp
= use
->cost_map
+ i
;
5068 /* Already tried this. */
5069 if (cand
->important
)
5072 if (iv_ca_cand_used_p (ivs
, cand
))
5076 iv_ca_set_cp (data
, ivs
, use
, cp
);
5077 act_cost
= iv_ca_extend (data
, ivs
, cand
, &act_delta
, NULL
);
5078 iv_ca_set_no_cp (data
, ivs
, use
);
5079 act_delta
= iv_ca_delta_add (use
, iv_ca_cand_for_use (ivs
, use
),
5082 if (act_cost
< best_cost
)
5084 best_cost
= act_cost
;
5087 iv_ca_delta_free (&best_delta
);
5088 best_delta
= act_delta
;
5091 iv_ca_delta_free (&act_delta
);
5095 iv_ca_delta_commit (data
, ivs
, best_delta
, true);
5096 iv_ca_delta_free (&best_delta
);
5098 return (best_cost
!= INFTY
);
5101 /* Finds an initial assignment of candidates to uses. */
5103 static struct iv_ca
*
5104 get_initial_solution (struct ivopts_data
*data
)
5106 struct iv_ca
*ivs
= iv_ca_new (data
);
5109 for (i
= 0; i
< n_iv_uses (data
); i
++)
5110 if (!try_add_cand_for (data
, ivs
, iv_use (data
, i
)))
5119 /* Tries to improve set of induction variables IVS. */
5122 try_improve_iv_set (struct ivopts_data
*data
, struct iv_ca
*ivs
)
5124 unsigned i
, acost
, best_cost
= iv_ca_cost (ivs
), n_ivs
;
5125 struct iv_ca_delta
*best_delta
= NULL
, *act_delta
, *tmp_delta
;
5126 struct iv_cand
*cand
;
5128 /* Try extending the set of induction variables by one. */
5129 for (i
= 0; i
< n_iv_cands (data
); i
++)
5131 cand
= iv_cand (data
, i
);
5133 if (iv_ca_cand_used_p (ivs
, cand
))
5136 acost
= iv_ca_extend (data
, ivs
, cand
, &act_delta
, &n_ivs
);
5140 /* If we successfully added the candidate and the set is small enough,
5141 try optimizing it by removing other candidates. */
5142 if (n_ivs
<= ALWAYS_PRUNE_CAND_SET_BOUND
)
5144 iv_ca_delta_commit (data
, ivs
, act_delta
, true);
5145 acost
= iv_ca_prune (data
, ivs
, cand
, &tmp_delta
);
5146 iv_ca_delta_commit (data
, ivs
, act_delta
, false);
5147 act_delta
= iv_ca_delta_join (act_delta
, tmp_delta
);
5150 if (acost
< best_cost
)
5153 iv_ca_delta_free (&best_delta
);
5154 best_delta
= act_delta
;
5157 iv_ca_delta_free (&act_delta
);
5162 /* Try removing the candidates from the set instead. */
5163 best_cost
= iv_ca_prune (data
, ivs
, NULL
, &best_delta
);
5165 /* Nothing more we can do. */
5170 iv_ca_delta_commit (data
, ivs
, best_delta
, true);
5171 gcc_assert (best_cost
== iv_ca_cost (ivs
));
5172 iv_ca_delta_free (&best_delta
);
5176 /* Attempts to find the optimal set of induction variables. We do simple
5177 greedy heuristic -- we try to replace at most one candidate in the selected
5178 solution and remove the unused ivs while this improves the cost. */
5180 static struct iv_ca
*
5181 find_optimal_iv_set (struct ivopts_data
*data
)
5187 /* Get the initial solution. */
5188 set
= get_initial_solution (data
);
5191 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5192 fprintf (dump_file
, "Unable to substitute for ivs, failed.\n");
5196 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5198 fprintf (dump_file
, "Initial set of candidates:\n");
5199 iv_ca_dump (data
, dump_file
, set
);
5202 while (try_improve_iv_set (data
, set
))
5204 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5206 fprintf (dump_file
, "Improved to:\n");
5207 iv_ca_dump (data
, dump_file
, set
);
5211 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5212 fprintf (dump_file
, "Final cost %d\n\n", iv_ca_cost (set
));
5214 for (i
= 0; i
< n_iv_uses (data
); i
++)
5216 use
= iv_use (data
, i
);
5217 use
->selected
= iv_ca_cand_for_use (set
, use
)->cand
;
5223 /* Creates a new induction variable corresponding to CAND. */
5226 create_new_iv (struct ivopts_data
*data
, struct iv_cand
*cand
)
5228 block_stmt_iterator incr_pos
;
5238 incr_pos
= bsi_last (ip_normal_pos (data
->current_loop
));
5242 incr_pos
= bsi_last (ip_end_pos (data
->current_loop
));
5247 /* Mark that the iv is preserved. */
5248 name_info (data
, cand
->var_before
)->preserve_biv
= true;
5249 name_info (data
, cand
->var_after
)->preserve_biv
= true;
5251 /* Rewrite the increment so that it uses var_before directly. */
5252 find_interesting_uses_op (data
, cand
->var_after
)->selected
= cand
;
5257 gimple_add_tmp_var (cand
->var_before
);
5258 add_referenced_tmp_var (cand
->var_before
);
5260 base
= unshare_expr (cand
->iv
->base
);
5262 create_iv (base
, unshare_expr (cand
->iv
->step
),
5263 cand
->var_before
, data
->current_loop
,
5264 &incr_pos
, after
, &cand
->var_before
, &cand
->var_after
);
5267 /* Creates new induction variables described in SET. */
5270 create_new_ivs (struct ivopts_data
*data
, struct iv_ca
*set
)
5273 struct iv_cand
*cand
;
5276 EXECUTE_IF_SET_IN_BITMAP (set
->cands
, 0, i
, bi
)
5278 cand
= iv_cand (data
, i
);
5279 create_new_iv (data
, cand
);
5283 /* Removes statement STMT (real or a phi node). If INCLUDING_DEFINED_NAME
5284 is true, remove also the ssa name defined by the statement. */
5287 remove_statement (tree stmt
, bool including_defined_name
)
5289 if (TREE_CODE (stmt
) == PHI_NODE
)
5291 if (!including_defined_name
)
5293 /* Prevent the ssa name defined by the statement from being removed. */
5294 SET_PHI_RESULT (stmt
, NULL
);
5296 remove_phi_node (stmt
, NULL_TREE
);
5300 block_stmt_iterator bsi
= bsi_for_stmt (stmt
);
5306 /* Rewrites USE (definition of iv used in a nonlinear expression)
5307 using candidate CAND. */
5310 rewrite_use_nonlinear_expr (struct ivopts_data
*data
,
5311 struct iv_use
*use
, struct iv_cand
*cand
)
5314 tree op
, stmts
, tgt
, ass
;
5315 block_stmt_iterator bsi
, pbsi
;
5317 /* An important special case -- if we are asked to express value of
5318 the original iv by itself, just exit; there is no need to
5319 introduce a new computation (that might also need casting the
5320 variable to unsigned and back). */
5321 if (cand
->pos
== IP_ORIGINAL
5322 && TREE_CODE (use
->stmt
) == MODIFY_EXPR
5323 && TREE_OPERAND (use
->stmt
, 0) == cand
->var_after
)
5325 op
= TREE_OPERAND (use
->stmt
, 1);
5327 /* Be a bit careful. In case variable is expressed in some
5328 complicated way, rewrite it so that we may get rid of this
5329 complicated expression. */
5330 if ((TREE_CODE (op
) == PLUS_EXPR
5331 || TREE_CODE (op
) == MINUS_EXPR
)
5332 && TREE_OPERAND (op
, 0) == cand
->var_before
5333 && TREE_CODE (TREE_OPERAND (op
, 1)) == INTEGER_CST
)
5337 comp
= get_computation (data
->current_loop
, use
, cand
);
5338 switch (TREE_CODE (use
->stmt
))
5341 tgt
= PHI_RESULT (use
->stmt
);
5343 /* If we should keep the biv, do not replace it. */
5344 if (name_info (data
, tgt
)->preserve_biv
)
5347 pbsi
= bsi
= bsi_start (bb_for_stmt (use
->stmt
));
5348 while (!bsi_end_p (pbsi
)
5349 && TREE_CODE (bsi_stmt (pbsi
)) == LABEL_EXPR
)
5357 tgt
= TREE_OPERAND (use
->stmt
, 0);
5358 bsi
= bsi_for_stmt (use
->stmt
);
5365 op
= force_gimple_operand (comp
, &stmts
, false, SSA_NAME_VAR (tgt
));
5367 if (TREE_CODE (use
->stmt
) == PHI_NODE
)
5370 bsi_insert_after (&bsi
, stmts
, BSI_CONTINUE_LINKING
);
5371 ass
= build2 (MODIFY_EXPR
, TREE_TYPE (tgt
), tgt
, op
);
5372 bsi_insert_after (&bsi
, ass
, BSI_NEW_STMT
);
5373 remove_statement (use
->stmt
, false);
5374 SSA_NAME_DEF_STMT (tgt
) = ass
;
5379 bsi_insert_before (&bsi
, stmts
, BSI_SAME_STMT
);
5380 TREE_OPERAND (use
->stmt
, 1) = op
;
5384 /* Replaces ssa name in index IDX by its basic variable. Callback for
5388 idx_remove_ssa_names (tree base
, tree
*idx
,
5389 void *data ATTRIBUTE_UNUSED
)
5393 if (TREE_CODE (*idx
) == SSA_NAME
)
5394 *idx
= SSA_NAME_VAR (*idx
);
5396 if (TREE_CODE (base
) == ARRAY_REF
)
5398 op
= &TREE_OPERAND (base
, 2);
5400 && TREE_CODE (*op
) == SSA_NAME
)
5401 *op
= SSA_NAME_VAR (*op
);
5402 op
= &TREE_OPERAND (base
, 3);
5404 && TREE_CODE (*op
) == SSA_NAME
)
5405 *op
= SSA_NAME_VAR (*op
);
5411 /* Unshares REF and replaces ssa names inside it by their basic variables. */
5414 unshare_and_remove_ssa_names (tree ref
)
5416 ref
= unshare_expr (ref
);
5417 for_each_index (&ref
, idx_remove_ssa_names
, NULL
);
5422 /* Extract the alias analysis info for the memory reference REF. There are
5423 several ways how this information may be stored and what precisely is
5424 its semantics depending on the type of the reference, but there always is
5425 somewhere hidden one _DECL node that is used to determine the set of
5426 virtual operands for the reference. The code below deciphers this jungle
5427 and extracts this single useful piece of information. */
5430 get_ref_tag (tree ref
)
5432 tree var
= get_base_address (ref
);
5438 if (TREE_CODE (var
) == INDIRECT_REF
)
5439 var
= TREE_OPERAND (var
, 0);
5440 if (TREE_CODE (var
) == SSA_NAME
)
5442 if (SSA_NAME_PTR_INFO (var
))
5444 tag
= SSA_NAME_PTR_INFO (var
)->name_mem_tag
;
5449 var
= SSA_NAME_VAR (var
);
5454 tag
= var_ann (var
)->type_mem_tag
;
5464 /* Copies the reference information from OLD_REF to NEW_REF. */
5467 copy_ref_info (tree new_ref
, tree old_ref
)
5469 if (TREE_CODE (old_ref
) == TARGET_MEM_REF
)
5470 copy_mem_ref_info (new_ref
, old_ref
);
5473 TMR_TAG (new_ref
) = get_ref_tag (old_ref
);
5474 TMR_ORIGINAL (new_ref
) = unshare_and_remove_ssa_names (old_ref
);
5478 /* Rewrites USE (address that is an iv) using candidate CAND. */
5481 rewrite_use_address (struct ivopts_data
*data
,
5482 struct iv_use
*use
, struct iv_cand
*cand
)
5484 struct affine_tree_combination aff
;
5485 block_stmt_iterator bsi
= bsi_for_stmt (use
->stmt
);
5488 get_computation_aff (data
->current_loop
, use
, cand
, use
->stmt
, &aff
);
5489 unshare_aff_combination (&aff
);
5491 ref
= create_mem_ref (&bsi
, TREE_TYPE (*use
->op_p
), &aff
);
5492 copy_ref_info (ref
, *use
->op_p
);
5496 /* Rewrites USE (the condition such that one of the arguments is an iv) using
5500 rewrite_use_compare (struct ivopts_data
*data
,
5501 struct iv_use
*use
, struct iv_cand
*cand
)
5504 tree
*op_p
, cond
, op
, stmts
, bound
;
5505 block_stmt_iterator bsi
= bsi_for_stmt (use
->stmt
);
5506 enum tree_code compare
;
5507 struct cost_pair
*cp
= get_use_iv_cost (data
, use
, cand
);
5512 tree var
= var_at_stmt (data
->current_loop
, cand
, use
->stmt
);
5513 tree var_type
= TREE_TYPE (var
);
5515 compare
= iv_elimination_compare (data
, use
);
5516 bound
= fold_convert (var_type
, bound
);
5517 op
= force_gimple_operand (unshare_expr (bound
), &stmts
,
5521 bsi_insert_before (&bsi
, stmts
, BSI_SAME_STMT
);
5523 *use
->op_p
= build2 (compare
, boolean_type_node
, var
, op
);
5524 update_stmt (use
->stmt
);
5528 /* The induction variable elimination failed; just express the original
5530 comp
= get_computation (data
->current_loop
, use
, cand
);
5533 op_p
= &TREE_OPERAND (cond
, 0);
5534 if (TREE_CODE (*op_p
) != SSA_NAME
5535 || zero_p (get_iv (data
, *op_p
)->step
))
5536 op_p
= &TREE_OPERAND (cond
, 1);
5538 op
= force_gimple_operand (comp
, &stmts
, true, SSA_NAME_VAR (*op_p
));
5540 bsi_insert_before (&bsi
, stmts
, BSI_SAME_STMT
);
5545 /* Ensure that operand *OP_P may be used at the end of EXIT without
5546 violating loop closed ssa form. */
5549 protect_loop_closed_ssa_form_use (edge exit
, use_operand_p op_p
)
5552 struct loop
*def_loop
;
5555 use
= USE_FROM_PTR (op_p
);
5556 if (TREE_CODE (use
) != SSA_NAME
)
5559 def_bb
= bb_for_stmt (SSA_NAME_DEF_STMT (use
));
5563 def_loop
= def_bb
->loop_father
;
5564 if (flow_bb_inside_loop_p (def_loop
, exit
->dest
))
5567 /* Try finding a phi node that copies the value out of the loop. */
5568 for (phi
= phi_nodes (exit
->dest
); phi
; phi
= PHI_CHAIN (phi
))
5569 if (PHI_ARG_DEF_FROM_EDGE (phi
, exit
) == use
)
5574 /* Create such a phi node. */
5575 tree new_name
= duplicate_ssa_name (use
, NULL
);
5577 phi
= create_phi_node (new_name
, exit
->dest
);
5578 SSA_NAME_DEF_STMT (new_name
) = phi
;
5579 add_phi_arg (phi
, use
, exit
);
5582 SET_USE (op_p
, PHI_RESULT (phi
));
5585 /* Ensure that operands of STMT may be used at the end of EXIT without
5586 violating loop closed ssa form. */
5589 protect_loop_closed_ssa_form (edge exit
, tree stmt
)
5592 use_operand_p use_p
;
5594 FOR_EACH_SSA_USE_OPERAND (use_p
, stmt
, iter
, SSA_OP_ALL_USES
)
5595 protect_loop_closed_ssa_form_use (exit
, use_p
);
5598 /* STMTS compute a value of a phi argument OP on EXIT of a loop. Arrange things
5599 so that they are emitted on the correct place, and so that the loop closed
5600 ssa form is preserved. */
5603 compute_phi_arg_on_exit (edge exit
, tree stmts
, tree op
)
5605 tree_stmt_iterator tsi
;
5606 block_stmt_iterator bsi
;
5607 tree phi
, stmt
, def
, next
;
5609 if (!single_pred_p (exit
->dest
))
5610 split_loop_exit_edge (exit
);
5612 /* Ensure there is label in exit->dest, so that we can
5614 tree_block_label (exit
->dest
);
5615 bsi
= bsi_after_labels (exit
->dest
);
5617 if (TREE_CODE (stmts
) == STATEMENT_LIST
)
5619 for (tsi
= tsi_start (stmts
); !tsi_end_p (tsi
); tsi_next (&tsi
))
5621 bsi_insert_after (&bsi
, tsi_stmt (tsi
), BSI_NEW_STMT
);
5622 protect_loop_closed_ssa_form (exit
, bsi_stmt (bsi
));
5627 bsi_insert_after (&bsi
, stmts
, BSI_NEW_STMT
);
5628 protect_loop_closed_ssa_form (exit
, bsi_stmt (bsi
));
5634 for (phi
= phi_nodes (exit
->dest
); phi
; phi
= next
)
5636 next
= PHI_CHAIN (phi
);
5638 if (PHI_ARG_DEF_FROM_EDGE (phi
, exit
) == op
)
5640 def
= PHI_RESULT (phi
);
5641 remove_statement (phi
, false);
5642 stmt
= build2 (MODIFY_EXPR
, TREE_TYPE (op
),
5644 SSA_NAME_DEF_STMT (def
) = stmt
;
5645 bsi_insert_after (&bsi
, stmt
, BSI_CONTINUE_LINKING
);
5650 /* Rewrites the final value of USE (that is only needed outside of the loop)
5651 using candidate CAND. */
5654 rewrite_use_outer (struct ivopts_data
*data
,
5655 struct iv_use
*use
, struct iv_cand
*cand
)
5658 tree value
, op
, stmts
, tgt
;
5661 switch (TREE_CODE (use
->stmt
))
5664 tgt
= PHI_RESULT (use
->stmt
);
5667 tgt
= TREE_OPERAND (use
->stmt
, 0);
5673 exit
= single_dom_exit (data
->current_loop
);
5679 struct cost_pair
*cp
= get_use_iv_cost (data
, use
, cand
);
5680 value
= unshare_expr (cp
->value
);
5683 value
= get_computation_at (data
->current_loop
,
5684 use
, cand
, last_stmt (exit
->src
));
5686 op
= force_gimple_operand (value
, &stmts
, true, SSA_NAME_VAR (tgt
));
5688 /* If we will preserve the iv anyway and we would need to perform
5689 some computation to replace the final value, do nothing. */
5690 if (stmts
&& name_info (data
, tgt
)->preserve_biv
)
5693 for (phi
= phi_nodes (exit
->dest
); phi
; phi
= PHI_CHAIN (phi
))
5695 use_operand_p use_p
= PHI_ARG_DEF_PTR_FROM_EDGE (phi
, exit
);
5697 if (USE_FROM_PTR (use_p
) == tgt
)
5698 SET_USE (use_p
, op
);
5702 compute_phi_arg_on_exit (exit
, stmts
, op
);
5704 /* Enable removal of the statement. We cannot remove it directly,
5705 since we may still need the aliasing information attached to the
5706 ssa name defined by it. */
5707 name_info (data
, tgt
)->iv
->have_use_for
= false;
5711 /* If the variable is going to be preserved anyway, there is nothing to
5713 if (name_info (data
, tgt
)->preserve_biv
)
5716 /* Otherwise we just need to compute the iv. */
5717 rewrite_use_nonlinear_expr (data
, use
, cand
);
5720 /* Rewrites USE using candidate CAND. */
5723 rewrite_use (struct ivopts_data
*data
,
5724 struct iv_use
*use
, struct iv_cand
*cand
)
5728 case USE_NONLINEAR_EXPR
:
5729 rewrite_use_nonlinear_expr (data
, use
, cand
);
5733 rewrite_use_outer (data
, use
, cand
);
5737 rewrite_use_address (data
, use
, cand
);
5741 rewrite_use_compare (data
, use
, cand
);
5747 update_stmt (use
->stmt
);
5750 /* Rewrite the uses using the selected induction variables. */
5753 rewrite_uses (struct ivopts_data
*data
)
5756 struct iv_cand
*cand
;
5759 for (i
= 0; i
< n_iv_uses (data
); i
++)
5761 use
= iv_use (data
, i
);
5762 cand
= use
->selected
;
5765 rewrite_use (data
, use
, cand
);
5769 /* Removes the ivs that are not used after rewriting. */
5772 remove_unused_ivs (struct ivopts_data
*data
)
5777 EXECUTE_IF_SET_IN_BITMAP (data
->relevant
, 0, j
, bi
)
5779 struct version_info
*info
;
5781 info
= ver_info (data
, j
);
5783 && !zero_p (info
->iv
->step
)
5785 && !info
->iv
->have_use_for
5786 && !info
->preserve_biv
)
5787 remove_statement (SSA_NAME_DEF_STMT (info
->iv
->ssa_name
), true);
5791 /* Frees data allocated by the optimization of a single loop. */
5794 free_loop_data (struct ivopts_data
*data
)
5800 htab_empty (data
->niters
);
5802 EXECUTE_IF_SET_IN_BITMAP (data
->relevant
, 0, i
, bi
)
5804 struct version_info
*info
;
5806 info
= ver_info (data
, i
);
5810 info
->has_nonlin_use
= false;
5811 info
->preserve_biv
= false;
5814 bitmap_clear (data
->relevant
);
5815 bitmap_clear (data
->important_candidates
);
5817 for (i
= 0; i
< n_iv_uses (data
); i
++)
5819 struct iv_use
*use
= iv_use (data
, i
);
5822 BITMAP_FREE (use
->related_cands
);
5823 for (j
= 0; j
< use
->n_map_members
; j
++)
5824 if (use
->cost_map
[j
].depends_on
)
5825 BITMAP_FREE (use
->cost_map
[j
].depends_on
);
5826 free (use
->cost_map
);
5829 VEC_truncate (iv_use_p
, data
->iv_uses
, 0);
5831 for (i
= 0; i
< n_iv_cands (data
); i
++)
5833 struct iv_cand
*cand
= iv_cand (data
, i
);
5837 if (cand
->depends_on
)
5838 BITMAP_FREE (cand
->depends_on
);
5841 VEC_truncate (iv_cand_p
, data
->iv_candidates
, 0);
5843 if (data
->version_info_size
< num_ssa_names
)
5845 data
->version_info_size
= 2 * num_ssa_names
;
5846 free (data
->version_info
);
5847 data
->version_info
= xcalloc (data
->version_info_size
,
5848 sizeof (struct version_info
));
5851 data
->max_inv_id
= 0;
5853 for (i
= 0; VEC_iterate (tree
, decl_rtl_to_reset
, i
, obj
); i
++)
5854 SET_DECL_RTL (obj
, NULL_RTX
);
5856 VEC_truncate (tree
, decl_rtl_to_reset
, 0);
5859 /* Finalizes data structures used by the iv optimization pass. LOOPS is the
5863 tree_ssa_iv_optimize_finalize (struct loops
*loops
, struct ivopts_data
*data
)
5867 for (i
= 1; i
< loops
->num
; i
++)
5868 if (loops
->parray
[i
])
5870 free (loops
->parray
[i
]->aux
);
5871 loops
->parray
[i
]->aux
= NULL
;
5874 free_loop_data (data
);
5875 free (data
->version_info
);
5876 BITMAP_FREE (data
->relevant
);
5877 BITMAP_FREE (data
->important_candidates
);
5878 htab_delete (data
->niters
);
5880 VEC_free (tree
, heap
, decl_rtl_to_reset
);
5881 VEC_free (iv_use_p
, heap
, data
->iv_uses
);
5882 VEC_free (iv_cand_p
, heap
, data
->iv_candidates
);
5885 /* Optimizes the LOOP. Returns true if anything changed. */
5888 tree_ssa_iv_optimize_loop (struct ivopts_data
*data
, struct loop
*loop
)
5890 bool changed
= false;
5891 struct iv_ca
*iv_ca
;
5894 data
->current_loop
= loop
;
5896 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5898 fprintf (dump_file
, "Processing loop %d\n", loop
->num
);
5900 exit
= single_dom_exit (loop
);
5903 fprintf (dump_file
, " single exit %d -> %d, exit condition ",
5904 exit
->src
->index
, exit
->dest
->index
);
5905 print_generic_expr (dump_file
, last_stmt (exit
->src
), TDF_SLIM
);
5906 fprintf (dump_file
, "\n");
5909 fprintf (dump_file
, "\n");
5912 /* For each ssa name determines whether it behaves as an induction variable
5914 if (!find_induction_variables (data
))
5917 /* Finds interesting uses (item 1). */
5918 find_interesting_uses (data
);
5919 if (n_iv_uses (data
) > MAX_CONSIDERED_USES
)
5922 /* Finds candidates for the induction variables (item 2). */
5923 find_iv_candidates (data
);
5925 /* Calculates the costs (item 3, part 1). */
5926 determine_use_iv_costs (data
);
5927 determine_iv_costs (data
);
5928 determine_set_costs (data
);
5930 /* Find the optimal set of induction variables (item 3, part 2). */
5931 iv_ca
= find_optimal_iv_set (data
);
5936 /* Create the new induction variables (item 4, part 1). */
5937 create_new_ivs (data
, iv_ca
);
5938 iv_ca_free (&iv_ca
);
5940 /* Rewrite the uses (item 4, part 2). */
5941 rewrite_uses (data
);
5943 /* Remove the ivs that are unused after rewriting. */
5944 remove_unused_ivs (data
);
5946 /* We have changed the structure of induction variables; it might happen
5947 that definitions in the scev database refer to some of them that were
5952 free_loop_data (data
);
5957 /* Main entry point. Optimizes induction variables in LOOPS. */
5960 tree_ssa_iv_optimize (struct loops
*loops
)
5963 struct ivopts_data data
;
5965 tree_ssa_iv_optimize_init (loops
, &data
);
5967 /* Optimize the loops starting with the innermost ones. */
5968 loop
= loops
->tree_root
;
5972 /* Scan the loops, inner ones first. */
5973 while (loop
!= loops
->tree_root
)
5975 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5976 flow_loop_dump (loop
, dump_file
, NULL
, 1);
5978 tree_ssa_iv_optimize_loop (&data
, loop
);
5990 tree_ssa_iv_optimize_finalize (loops
, &data
);