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,
722 if (!nfe_desc->valid_p)
725 return &nfe_desc->niter;
728 /* Returns structure describing number of iterations determined from
729 single dominating exit of DATA->current_loop, or NULL if something
732 static struct tree_niter_desc *
733 niter_for_single_dom_exit (struct ivopts_data *data)
735 edge exit = single_dom_exit (data->current_loop);
740 return niter_for_exit (data, exit);
743 /* Initializes data structures used by the iv optimization pass, stored
744 in DATA. LOOPS is the loop tree. */
747 tree_ssa_iv_optimize_init (struct loops *loops, struct ivopts_data *data)
751 data->version_info_size = 2 * num_ssa_names;
752 data->version_info = xcalloc (data->version_info_size,
753 sizeof (struct version_info));
754 data->relevant = BITMAP_ALLOC (NULL);
755 data->important_candidates = BITMAP_ALLOC (NULL);
756 data->max_inv_id = 0;
757 data->niters = htab_create (10, nfe_hash, nfe_eq, free);
759 for (i = 1; i < loops->num; i++)
760 if (loops->parray[i])
761 loops->parray[i]->aux = xcalloc (1, sizeof (struct loop_data));
763 data->iv_uses = VEC_alloc (iv_use_p, heap, 20);
764 data->iv_candidates = VEC_alloc (iv_cand_p, heap, 20);
765 decl_rtl_to_reset = VEC_alloc (tree, heap, 20);
768 /* Returns a memory object to that EXPR points. In case we are able to
769 determine that it does not point to any such object, NULL is returned. */
772 determine_base_object (tree expr)
774 enum tree_code code = TREE_CODE (expr);
775 tree base, obj, op0, op1;
777 if (!POINTER_TYPE_P (TREE_TYPE (expr)))
786 obj = TREE_OPERAND (expr, 0);
787 base = get_base_address (obj);
792 if (TREE_CODE (base) == INDIRECT_REF)
793 return determine_base_object (TREE_OPERAND (base, 0));
795 return fold_convert (ptr_type_node,
796 build_fold_addr_expr (base));
800 op0 = determine_base_object (TREE_OPERAND (expr, 0));
801 op1 = determine_base_object (TREE_OPERAND (expr, 1));
807 return (code == PLUS_EXPR
809 : fold_build1 (NEGATE_EXPR, ptr_type_node, op1));
811 return fold_build2 (code, ptr_type_node, op0, op1);
815 return determine_base_object (TREE_OPERAND (expr, 0));
818 return fold_convert (ptr_type_node, expr);
822 /* Allocates an induction variable with given initial value BASE and step STEP
826 alloc_iv (tree base, tree step)
828 struct iv *iv = xcalloc (1, sizeof (struct iv));
830 if (step && integer_zerop (step))
834 iv->base_object = determine_base_object (base);
837 iv->have_use_for = false;
839 iv->ssa_name = NULL_TREE;
844 /* Sets STEP and BASE for induction variable IV. */
847 set_iv (struct ivopts_data *data, tree iv, tree base, tree step)
849 struct version_info *info = name_info (data, iv);
851 gcc_assert (!info->iv);
853 bitmap_set_bit (data->relevant, SSA_NAME_VERSION (iv));
854 info->iv = alloc_iv (base, step);
855 info->iv->ssa_name = iv;
858 /* Finds induction variable declaration for VAR. */
861 get_iv (struct ivopts_data *data, tree var)
865 if (!name_info (data, var)->iv)
867 bb = bb_for_stmt (SSA_NAME_DEF_STMT (var));
870 || !flow_bb_inside_loop_p (data->current_loop, bb))
871 set_iv (data, var, var, NULL_TREE);
874 return name_info (data, var)->iv;
877 /* Determines the step of a biv defined in PHI. Returns NULL if PHI does
878 not define a simple affine biv with nonzero step. */
881 determine_biv_step (tree phi)
883 struct loop *loop = bb_for_stmt (phi)->loop_father;
884 tree name = PHI_RESULT (phi), base, step;
886 if (!is_gimple_reg (name))
889 if (!simple_iv (loop, phi, name, &base, &step, true))
898 /* Returns true if EXP is a ssa name that occurs in an abnormal phi node. */
901 abnormal_ssa_name_p (tree exp)
906 if (TREE_CODE (exp) != SSA_NAME)
909 return SSA_NAME_OCCURS_IN_ABNORMAL_PHI (exp) != 0;
912 /* Returns false if BASE or INDEX contains a ssa name that occurs in an
913 abnormal phi node. Callback for for_each_index. */
916 idx_contains_abnormal_ssa_name_p (tree base, tree *index,
917 void *data ATTRIBUTE_UNUSED)
919 if (TREE_CODE (base) == ARRAY_REF)
921 if (abnormal_ssa_name_p (TREE_OPERAND (base, 2)))
923 if (abnormal_ssa_name_p (TREE_OPERAND (base, 3)))
927 return !abnormal_ssa_name_p (*index);
930 /* Returns true if EXPR contains a ssa name that occurs in an
931 abnormal phi node. */
934 contains_abnormal_ssa_name_p (tree expr)
937 enum tree_code_class class;
942 code = TREE_CODE (expr);
943 class = TREE_CODE_CLASS (code);
945 if (code == SSA_NAME)
946 return SSA_NAME_OCCURS_IN_ABNORMAL_PHI (expr) != 0;
948 if (code == INTEGER_CST
949 || is_gimple_min_invariant (expr))
952 if (code == ADDR_EXPR)
953 return !for_each_index (&TREE_OPERAND (expr, 0),
954 idx_contains_abnormal_ssa_name_p,
961 if (contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 1)))
966 if (contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 0)))
978 /* Finds basic ivs. */
981 find_bivs (struct ivopts_data *data)
983 tree phi, step, type, base;
985 struct loop *loop = data->current_loop;
987 for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi))
989 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)))
992 step = determine_biv_step (phi);
996 base = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop));
997 base = expand_simple_operations (base);
998 if (contains_abnormal_ssa_name_p (base)
999 || contains_abnormal_ssa_name_p (step))
1002 type = TREE_TYPE (PHI_RESULT (phi));
1003 base = fold_convert (type, base);
1005 step = fold_convert (type, step);
1007 set_iv (data, PHI_RESULT (phi), base, step);
1014 /* Marks basic ivs. */
1017 mark_bivs (struct ivopts_data *data)
1020 struct iv *iv, *incr_iv;
1021 struct loop *loop = data->current_loop;
1022 basic_block incr_bb;
1024 for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi))
1026 iv = get_iv (data, PHI_RESULT (phi));
1030 var = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (loop));
1031 incr_iv = get_iv (data, var);
1035 /* If the increment is in the subloop, ignore it. */
1036 incr_bb = bb_for_stmt (SSA_NAME_DEF_STMT (var));
1037 if (incr_bb->loop_father != data->current_loop
1038 || (incr_bb->flags & BB_IRREDUCIBLE_LOOP))
1042 incr_iv->biv_p = true;
1046 /* Checks whether STMT defines a linear induction variable and stores its
1047 parameters to BASE and STEP. */
1050 find_givs_in_stmt_scev (struct ivopts_data *data, tree stmt,
1051 tree *base, tree *step)
1054 struct loop *loop = data->current_loop;
1059 if (TREE_CODE (stmt) != MODIFY_EXPR)
1062 lhs = TREE_OPERAND (stmt, 0);
1063 if (TREE_CODE (lhs) != SSA_NAME)
1066 if (!simple_iv (loop, stmt, TREE_OPERAND (stmt, 1), base, step, true))
1068 *base = expand_simple_operations (*base);
1070 if (contains_abnormal_ssa_name_p (*base)
1071 || contains_abnormal_ssa_name_p (*step))
1077 /* Finds general ivs in statement STMT. */
1080 find_givs_in_stmt (struct ivopts_data *data, tree stmt)
1084 if (!find_givs_in_stmt_scev (data, stmt, &base, &step))
1087 set_iv (data, TREE_OPERAND (stmt, 0), base, step);
1090 /* Finds general ivs in basic block BB. */
1093 find_givs_in_bb (struct ivopts_data *data, basic_block bb)
1095 block_stmt_iterator bsi;
1097 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
1098 find_givs_in_stmt (data, bsi_stmt (bsi));
1101 /* Finds general ivs. */
1104 find_givs (struct ivopts_data *data)
1106 struct loop *loop = data->current_loop;
1107 basic_block *body = get_loop_body_in_dom_order (loop);
1110 for (i = 0; i < loop->num_nodes; i++)
1111 find_givs_in_bb (data, body[i]);
1115 /* For each ssa name defined in LOOP determines whether it is an induction
1116 variable and if so, its initial value and step. */
1119 find_induction_variables (struct ivopts_data *data)
1124 if (!find_bivs (data))
1130 if (dump_file && (dump_flags & TDF_DETAILS))
1132 struct tree_niter_desc *niter;
1134 niter = niter_for_single_dom_exit (data);
1138 fprintf (dump_file, " number of iterations ");
1139 print_generic_expr (dump_file, niter->niter, TDF_SLIM);
1140 fprintf (dump_file, "\n");
1142 fprintf (dump_file, " may be zero if ");
1143 print_generic_expr (dump_file, niter->may_be_zero, TDF_SLIM);
1144 fprintf (dump_file, "\n");
1145 fprintf (dump_file, "\n");
1148 fprintf (dump_file, "Induction variables:\n\n");
1150 EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
1152 if (ver_info (data, i)->iv)
1153 dump_iv (dump_file, ver_info (data, i)->iv);
1160 /* Records a use of type USE_TYPE at *USE_P in STMT whose value is IV. */
1162 static struct iv_use *
1163 record_use (struct ivopts_data *data, tree *use_p, struct iv *iv,
1164 tree stmt, enum use_type use_type)
1166 struct iv_use *use = xcalloc (1, sizeof (struct iv_use));
1168 use->id = n_iv_uses (data);
1169 use->type = use_type;
1173 use->related_cands = BITMAP_ALLOC (NULL);
1175 /* To avoid showing ssa name in the dumps, if it was not reset by the
1177 iv->ssa_name = NULL_TREE;
1179 if (dump_file && (dump_flags & TDF_DETAILS))
1180 dump_use (dump_file, use);
1182 VEC_safe_push (iv_use_p, heap, data->iv_uses, use);
1187 /* Checks whether OP is a loop-level invariant and if so, records it.
1188 NONLINEAR_USE is true if the invariant is used in a way we do not
1189 handle specially. */
1192 record_invariant (struct ivopts_data *data, tree op, bool nonlinear_use)
1195 struct version_info *info;
1197 if (TREE_CODE (op) != SSA_NAME
1198 || !is_gimple_reg (op))
1201 bb = bb_for_stmt (SSA_NAME_DEF_STMT (op));
1203 && flow_bb_inside_loop_p (data->current_loop, bb))
1206 info = name_info (data, op);
1208 info->has_nonlin_use |= nonlinear_use;
1210 info->inv_id = ++data->max_inv_id;
1211 bitmap_set_bit (data->relevant, SSA_NAME_VERSION (op));
1214 /* Checks whether the use OP is interesting and if so, records it
1217 static struct iv_use *
1218 find_interesting_uses_outer_or_nonlin (struct ivopts_data *data, tree op,
1226 if (TREE_CODE (op) != SSA_NAME)
1229 iv = get_iv (data, op);
1233 if (iv->have_use_for)
1235 use = iv_use (data, iv->use_id);
1237 gcc_assert (use->type == USE_NONLINEAR_EXPR
1238 || use->type == USE_OUTER);
1240 if (type == USE_NONLINEAR_EXPR)
1241 use->type = USE_NONLINEAR_EXPR;
1245 if (zero_p (iv->step))
1247 record_invariant (data, op, true);
1250 iv->have_use_for = true;
1252 civ = xmalloc (sizeof (struct iv));
1255 stmt = SSA_NAME_DEF_STMT (op);
1256 gcc_assert (TREE_CODE (stmt) == PHI_NODE
1257 || TREE_CODE (stmt) == MODIFY_EXPR);
1259 use = record_use (data, NULL, civ, stmt, type);
1260 iv->use_id = use->id;
1265 /* Checks whether the use OP is interesting and if so, records it. */
1267 static struct iv_use *
1268 find_interesting_uses_op (struct ivopts_data *data, tree op)
1270 return find_interesting_uses_outer_or_nonlin (data, op, USE_NONLINEAR_EXPR);
1273 /* Records a definition of induction variable OP that is used outside of the
1276 static struct iv_use *
1277 find_interesting_uses_outer (struct ivopts_data *data, tree op)
1279 return find_interesting_uses_outer_or_nonlin (data, op, USE_OUTER);
1282 /* Checks whether the condition *COND_P in STMT is interesting
1283 and if so, records it. */
1286 find_interesting_uses_cond (struct ivopts_data *data, tree stmt, tree *cond_p)
1290 struct iv *iv0 = NULL, *iv1 = NULL, *civ;
1292 tree zero = integer_zero_node;
1294 const_iv.step = NULL_TREE;
1296 if (TREE_CODE (*cond_p) != SSA_NAME
1297 && !COMPARISON_CLASS_P (*cond_p))
1300 if (TREE_CODE (*cond_p) == SSA_NAME)
1307 op0_p = &TREE_OPERAND (*cond_p, 0);
1308 op1_p = &TREE_OPERAND (*cond_p, 1);
1311 if (TREE_CODE (*op0_p) == SSA_NAME)
1312 iv0 = get_iv (data, *op0_p);
1316 if (TREE_CODE (*op1_p) == SSA_NAME)
1317 iv1 = get_iv (data, *op1_p);
1321 if (/* When comparing with non-invariant value, we may not do any senseful
1322 induction variable elimination. */
1324 /* Eliminating condition based on two ivs would be nontrivial.
1325 ??? TODO -- it is not really important to handle this case. */
1326 || (!zero_p (iv0->step) && !zero_p (iv1->step)))
1328 find_interesting_uses_op (data, *op0_p);
1329 find_interesting_uses_op (data, *op1_p);
1333 if (zero_p (iv0->step) && zero_p (iv1->step))
1335 /* If both are invariants, this is a work for unswitching. */
1339 civ = xmalloc (sizeof (struct iv));
1340 *civ = zero_p (iv0->step) ? *iv1: *iv0;
1341 record_use (data, cond_p, civ, stmt, USE_COMPARE);
1344 /* Returns true if expression EXPR is obviously invariant in LOOP,
1345 i.e. if all its operands are defined outside of the LOOP. */
1348 expr_invariant_in_loop_p (struct loop *loop, tree expr)
1353 if (is_gimple_min_invariant (expr))
1356 if (TREE_CODE (expr) == SSA_NAME)
1358 def_bb = bb_for_stmt (SSA_NAME_DEF_STMT (expr));
1360 && flow_bb_inside_loop_p (loop, def_bb))
1369 len = TREE_CODE_LENGTH (TREE_CODE (expr));
1370 for (i = 0; i < len; i++)
1371 if (!expr_invariant_in_loop_p (loop, TREE_OPERAND (expr, i)))
1377 /* Cumulates the steps of indices into DATA and replaces their values with the
1378 initial ones. Returns false when the value of the index cannot be determined.
1379 Callback for for_each_index. */
1381 struct ifs_ivopts_data
1383 struct ivopts_data *ivopts_data;
1389 idx_find_step (tree base, tree *idx, void *data)
1391 struct ifs_ivopts_data *dta = data;
1393 tree step, iv_step, lbound, off;
1394 struct loop *loop = dta->ivopts_data->current_loop;
1396 if (TREE_CODE (base) == MISALIGNED_INDIRECT_REF
1397 || TREE_CODE (base) == ALIGN_INDIRECT_REF)
1400 /* If base is a component ref, require that the offset of the reference
1402 if (TREE_CODE (base) == COMPONENT_REF)
1404 off = component_ref_field_offset (base);
1405 return expr_invariant_in_loop_p (loop, off);
1408 /* If base is array, first check whether we will be able to move the
1409 reference out of the loop (in order to take its address in strength
1410 reduction). In order for this to work we need both lower bound
1411 and step to be loop invariants. */
1412 if (TREE_CODE (base) == ARRAY_REF)
1414 step = array_ref_element_size (base);
1415 lbound = array_ref_low_bound (base);
1417 if (!expr_invariant_in_loop_p (loop, step)
1418 || !expr_invariant_in_loop_p (loop, lbound))
1422 if (TREE_CODE (*idx) != SSA_NAME)
1425 iv = get_iv (dta->ivopts_data, *idx);
1434 if (TREE_CODE (base) == ARRAY_REF)
1436 step = array_ref_element_size (base);
1438 /* We only handle addresses whose step is an integer constant. */
1439 if (TREE_CODE (step) != INTEGER_CST)
1443 /* The step for pointer arithmetics already is 1 byte. */
1444 step = build_int_cst (sizetype, 1);
1446 iv_step = convert_step (dta->ivopts_data->current_loop,
1447 sizetype, iv->base, iv->step, dta->stmt);
1451 /* The index might wrap. */
1455 step = fold_build2 (MULT_EXPR, sizetype, step, iv_step);
1458 *dta->step_p = step;
1460 *dta->step_p = fold_build2 (PLUS_EXPR, sizetype, *dta->step_p, step);
1465 /* Records use in index IDX. Callback for for_each_index. Ivopts data
1466 object is passed to it in DATA. */
1469 idx_record_use (tree base, tree *idx,
1472 find_interesting_uses_op (data, *idx);
1473 if (TREE_CODE (base) == ARRAY_REF)
1475 find_interesting_uses_op (data, array_ref_element_size (base));
1476 find_interesting_uses_op (data, array_ref_low_bound (base));
1481 /* Returns true if memory reference REF may be unaligned. */
1484 may_be_unaligned_p (tree ref)
1488 HOST_WIDE_INT bitsize;
1489 HOST_WIDE_INT bitpos;
1491 enum machine_mode mode;
1492 int unsignedp, volatilep;
1493 unsigned base_align;
1495 /* TARGET_MEM_REFs are translated directly to valid MEMs on the target,
1496 thus they are not misaligned. */
1497 if (TREE_CODE (ref) == TARGET_MEM_REF)
1500 /* The test below is basically copy of what expr.c:normal_inner_ref
1501 does to check whether the object must be loaded by parts when
1502 STRICT_ALIGNMENT is true. */
1503 base = get_inner_reference (ref, &bitsize, &bitpos, &toffset, &mode,
1504 &unsignedp, &volatilep, true);
1505 base_type = TREE_TYPE (base);
1506 base_align = TYPE_ALIGN (base_type);
1509 && (base_align < GET_MODE_ALIGNMENT (mode)
1510 || bitpos % GET_MODE_ALIGNMENT (mode) != 0
1511 || bitpos % BITS_PER_UNIT != 0))
1517 /* Finds addresses in *OP_P inside STMT. */
1520 find_interesting_uses_address (struct ivopts_data *data, tree stmt, tree *op_p)
1522 tree base = *op_p, step = NULL;
1524 struct ifs_ivopts_data ifs_ivopts_data;
1526 /* Do not play with volatile memory references. A bit too conservative,
1527 perhaps, but safe. */
1528 if (stmt_ann (stmt)->has_volatile_ops)
1531 /* Ignore bitfields for now. Not really something terribly complicated
1533 if (TREE_CODE (base) == COMPONENT_REF
1534 && DECL_NONADDRESSABLE_P (TREE_OPERAND (base, 1)))
1537 if (STRICT_ALIGNMENT
1538 && may_be_unaligned_p (base))
1541 base = unshare_expr (base);
1543 if (TREE_CODE (base) == TARGET_MEM_REF)
1545 tree type = build_pointer_type (TREE_TYPE (base));
1549 && TREE_CODE (TMR_BASE (base)) == SSA_NAME)
1551 civ = get_iv (data, TMR_BASE (base));
1555 TMR_BASE (base) = civ->base;
1558 if (TMR_INDEX (base)
1559 && TREE_CODE (TMR_INDEX (base)) == SSA_NAME)
1561 civ = get_iv (data, TMR_INDEX (base));
1565 TMR_INDEX (base) = civ->base;
1570 if (TMR_STEP (base))
1571 astep = fold_build2 (MULT_EXPR, type, TMR_STEP (base), astep);
1574 step = fold_build2 (PLUS_EXPR, type, step, astep);
1582 base = tree_mem_ref_addr (type, base);
1586 ifs_ivopts_data.ivopts_data = data;
1587 ifs_ivopts_data.stmt = stmt;
1588 ifs_ivopts_data.step_p = &step;
1589 if (!for_each_index (&base, idx_find_step, &ifs_ivopts_data)
1593 gcc_assert (TREE_CODE (base) != ALIGN_INDIRECT_REF);
1594 gcc_assert (TREE_CODE (base) != MISALIGNED_INDIRECT_REF);
1596 base = build_fold_addr_expr (base);
1599 civ = alloc_iv (base, step);
1600 record_use (data, op_p, civ, stmt, USE_ADDRESS);
1604 for_each_index (op_p, idx_record_use, data);
1607 /* Finds and records invariants used in STMT. */
1610 find_invariants_stmt (struct ivopts_data *data, tree stmt)
1613 use_operand_p use_p;
1616 FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE)
1618 op = USE_FROM_PTR (use_p);
1619 record_invariant (data, op, false);
1623 /* Finds interesting uses of induction variables in the statement STMT. */
1626 find_interesting_uses_stmt (struct ivopts_data *data, tree stmt)
1631 use_operand_p use_p;
1633 find_invariants_stmt (data, stmt);
1635 if (TREE_CODE (stmt) == COND_EXPR)
1637 find_interesting_uses_cond (data, stmt, &COND_EXPR_COND (stmt));
1641 if (TREE_CODE (stmt) == MODIFY_EXPR)
1643 lhs = TREE_OPERAND (stmt, 0);
1644 rhs = TREE_OPERAND (stmt, 1);
1646 if (TREE_CODE (lhs) == SSA_NAME)
1648 /* If the statement defines an induction variable, the uses are not
1649 interesting by themselves. */
1651 iv = get_iv (data, lhs);
1653 if (iv && !zero_p (iv->step))
1657 switch (TREE_CODE_CLASS (TREE_CODE (rhs)))
1659 case tcc_comparison:
1660 find_interesting_uses_cond (data, stmt, &TREE_OPERAND (stmt, 1));
1664 find_interesting_uses_address (data, stmt, &TREE_OPERAND (stmt, 1));
1665 if (REFERENCE_CLASS_P (lhs))
1666 find_interesting_uses_address (data, stmt, &TREE_OPERAND (stmt, 0));
1672 if (REFERENCE_CLASS_P (lhs)
1673 && is_gimple_val (rhs))
1675 find_interesting_uses_address (data, stmt, &TREE_OPERAND (stmt, 0));
1676 find_interesting_uses_op (data, rhs);
1680 /* TODO -- we should also handle address uses of type
1682 memory = call (whatever);
1689 if (TREE_CODE (stmt) == PHI_NODE
1690 && bb_for_stmt (stmt) == data->current_loop->header)
1692 lhs = PHI_RESULT (stmt);
1693 iv = get_iv (data, lhs);
1695 if (iv && !zero_p (iv->step))
1699 FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE)
1701 op = USE_FROM_PTR (use_p);
1703 if (TREE_CODE (op) != SSA_NAME)
1706 iv = get_iv (data, op);
1710 find_interesting_uses_op (data, op);
1714 /* Finds interesting uses of induction variables outside of loops
1715 on loop exit edge EXIT. */
1718 find_interesting_uses_outside (struct ivopts_data *data, edge exit)
1722 for (phi = phi_nodes (exit->dest); phi; phi = PHI_CHAIN (phi))
1724 def = PHI_ARG_DEF_FROM_EDGE (phi, exit);
1725 find_interesting_uses_outer (data, def);
1729 /* Finds uses of the induction variables that are interesting. */
1732 find_interesting_uses (struct ivopts_data *data)
1735 block_stmt_iterator bsi;
1737 basic_block *body = get_loop_body (data->current_loop);
1739 struct version_info *info;
1742 if (dump_file && (dump_flags & TDF_DETAILS))
1743 fprintf (dump_file, "Uses:\n\n");
1745 for (i = 0; i < data->current_loop->num_nodes; i++)
1750 FOR_EACH_EDGE (e, ei, bb->succs)
1751 if (e->dest != EXIT_BLOCK_PTR
1752 && !flow_bb_inside_loop_p (data->current_loop, e->dest))
1753 find_interesting_uses_outside (data, e);
1755 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
1756 find_interesting_uses_stmt (data, phi);
1757 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
1758 find_interesting_uses_stmt (data, bsi_stmt (bsi));
1761 if (dump_file && (dump_flags & TDF_DETAILS))
1765 fprintf (dump_file, "\n");
1767 EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
1769 info = ver_info (data, i);
1772 fprintf (dump_file, " ");
1773 print_generic_expr (dump_file, info->name, TDF_SLIM);
1774 fprintf (dump_file, " is invariant (%d)%s\n",
1775 info->inv_id, info->has_nonlin_use ? "" : ", eliminable");
1779 fprintf (dump_file, "\n");
1785 /* Strips constant offsets from EXPR and stores them to OFFSET. If INSIDE_ADDR
1786 is true, assume we are inside an address. If TOP_COMPREF is true, assume
1787 we are at the top-level of the processed address. */
1790 strip_offset_1 (tree expr, bool inside_addr, bool top_compref,
1791 unsigned HOST_WIDE_INT *offset)
1793 tree op0 = NULL_TREE, op1 = NULL_TREE, tmp, step;
1794 enum tree_code code;
1795 tree type, orig_type = TREE_TYPE (expr);
1796 unsigned HOST_WIDE_INT off0, off1, st;
1797 tree orig_expr = expr;
1801 type = TREE_TYPE (expr);
1802 code = TREE_CODE (expr);
1808 if (!cst_and_fits_in_hwi (expr)
1812 *offset = int_cst_value (expr);
1813 return build_int_cst_type (orig_type, 0);
1817 op0 = TREE_OPERAND (expr, 0);
1818 op1 = TREE_OPERAND (expr, 1);
1820 op0 = strip_offset_1 (op0, false, false, &off0);
1821 op1 = strip_offset_1 (op1, false, false, &off1);
1823 *offset = (code == PLUS_EXPR ? off0 + off1 : off0 - off1);
1824 if (op0 == TREE_OPERAND (expr, 0)
1825 && op1 == TREE_OPERAND (expr, 1))
1830 else if (zero_p (op0))
1832 if (code == PLUS_EXPR)
1835 expr = fold_build1 (NEGATE_EXPR, type, op1);
1838 expr = fold_build2 (code, type, op0, op1);
1840 return fold_convert (orig_type, expr);
1846 step = array_ref_element_size (expr);
1847 if (!cst_and_fits_in_hwi (step))
1850 st = int_cst_value (step);
1851 op1 = TREE_OPERAND (expr, 1);
1852 op1 = strip_offset_1 (op1, false, false, &off1);
1853 *offset = off1 * st;
1858 /* Strip the component reference completely. */
1859 op0 = TREE_OPERAND (expr, 0);
1860 op0 = strip_offset_1 (op0, inside_addr, top_compref, &off0);
1870 tmp = component_ref_field_offset (expr);
1872 && cst_and_fits_in_hwi (tmp))
1874 /* Strip the component reference completely. */
1875 op0 = TREE_OPERAND (expr, 0);
1876 op0 = strip_offset_1 (op0, inside_addr, top_compref, &off0);
1877 *offset = off0 + int_cst_value (tmp);
1883 op0 = TREE_OPERAND (expr, 0);
1884 op0 = strip_offset_1 (op0, true, true, &off0);
1887 if (op0 == TREE_OPERAND (expr, 0))
1890 expr = build_fold_addr_expr (op0);
1891 return fold_convert (orig_type, expr);
1894 inside_addr = false;
1901 /* Default handling of expressions for that we want to recurse into
1902 the first operand. */
1903 op0 = TREE_OPERAND (expr, 0);
1904 op0 = strip_offset_1 (op0, inside_addr, false, &off0);
1907 if (op0 == TREE_OPERAND (expr, 0)
1908 && (!op1 || op1 == TREE_OPERAND (expr, 1)))
1911 expr = copy_node (expr);
1912 TREE_OPERAND (expr, 0) = op0;
1914 TREE_OPERAND (expr, 1) = op1;
1916 /* Inside address, we might strip the top level component references,
1917 thus changing type of the expression. Handling of ADDR_EXPR
1919 expr = fold_convert (orig_type, expr);
1924 /* Strips constant offsets from EXPR and stores them to OFFSET. */
1927 strip_offset (tree expr, unsigned HOST_WIDE_INT *offset)
1929 return strip_offset_1 (expr, false, false, offset);
1932 /* Returns variant of TYPE that can be used as base for different uses.
1933 For integer types, we return unsigned variant of the type, which
1934 avoids problems with overflows. For pointer types, we return void *. */
1937 generic_type_for (tree type)
1939 if (POINTER_TYPE_P (type))
1940 return ptr_type_node;
1942 if (TYPE_UNSIGNED (type))
1945 return unsigned_type_for (type);
1948 /* Records invariants in *EXPR_P. Callback for walk_tree. DATA contains
1949 the bitmap to that we should store it. */
1951 static struct ivopts_data *fd_ivopts_data;
1953 find_depends (tree *expr_p, int *ws ATTRIBUTE_UNUSED, void *data)
1955 bitmap *depends_on = data;
1956 struct version_info *info;
1958 if (TREE_CODE (*expr_p) != SSA_NAME)
1960 info = name_info (fd_ivopts_data, *expr_p);
1962 if (!info->inv_id || info->has_nonlin_use)
1966 *depends_on = BITMAP_ALLOC (NULL);
1967 bitmap_set_bit (*depends_on, info->inv_id);
1972 /* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and
1973 position to POS. If USE is not NULL, the candidate is set as related to
1974 it. If both BASE and STEP are NULL, we add a pseudocandidate for the
1975 replacement of the final value of the iv by a direct computation. */
1977 static struct iv_cand *
1978 add_candidate_1 (struct ivopts_data *data,
1979 tree base, tree step, bool important, enum iv_position pos,
1980 struct iv_use *use, tree incremented_at)
1983 struct iv_cand *cand = NULL;
1984 tree type, orig_type;
1988 orig_type = TREE_TYPE (base);
1989 type = generic_type_for (orig_type);
1990 if (type != orig_type)
1992 base = fold_convert (type, base);
1994 step = fold_convert (type, step);
1998 for (i = 0; i < n_iv_cands (data); i++)
2000 cand = iv_cand (data, i);
2002 if (cand->pos != pos)
2005 if (cand->incremented_at != incremented_at)
2019 if (!operand_equal_p (base, cand->iv->base, 0))
2022 if (zero_p (cand->iv->step))
2029 if (step && operand_equal_p (step, cand->iv->step, 0))
2034 if (i == n_iv_cands (data))
2036 cand = xcalloc (1, sizeof (struct iv_cand));
2042 cand->iv = alloc_iv (base, step);
2045 if (pos != IP_ORIGINAL && cand->iv)
2047 cand->var_before = create_tmp_var_raw (TREE_TYPE (base), "ivtmp");
2048 cand->var_after = cand->var_before;
2050 cand->important = important;
2051 cand->incremented_at = incremented_at;
2052 VEC_safe_push (iv_cand_p, heap, data->iv_candidates, cand);
2055 && TREE_CODE (step) != INTEGER_CST)
2057 fd_ivopts_data = data;
2058 walk_tree (&step, find_depends, &cand->depends_on, NULL);
2061 if (dump_file && (dump_flags & TDF_DETAILS))
2062 dump_cand (dump_file, cand);
2065 if (important && !cand->important)
2067 cand->important = true;
2068 if (dump_file && (dump_flags & TDF_DETAILS))
2069 fprintf (dump_file, "Candidate %d is important\n", cand->id);
2074 bitmap_set_bit (use->related_cands, i);
2075 if (dump_file && (dump_flags & TDF_DETAILS))
2076 fprintf (dump_file, "Candidate %d is related to use %d\n",
2083 /* Returns true if incrementing the induction variable at the end of the LOOP
2086 The purpose is to avoid splitting latch edge with a biv increment, thus
2087 creating a jump, possibly confusing other optimization passes and leaving
2088 less freedom to scheduler. So we allow IP_END_POS only if IP_NORMAL_POS
2089 is not available (so we do not have a better alternative), or if the latch
2090 edge is already nonempty. */
2093 allow_ip_end_pos_p (struct loop *loop)
2095 if (!ip_normal_pos (loop))
2098 if (!empty_block_p (ip_end_pos (loop)))
2104 /* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and
2105 position to POS. If USE is not NULL, the candidate is set as related to
2106 it. The candidate computation is scheduled on all available positions. */
2109 add_candidate (struct ivopts_data *data,
2110 tree base, tree step, bool important, struct iv_use *use)
2112 if (ip_normal_pos (data->current_loop))
2113 add_candidate_1 (data, base, step, important, IP_NORMAL, use, NULL_TREE);
2114 if (ip_end_pos (data->current_loop)
2115 && allow_ip_end_pos_p (data->current_loop))
2116 add_candidate_1 (data, base, step, important, IP_END, use, NULL_TREE);
2119 /* Add a standard "0 + 1 * iteration" iv candidate for a
2120 type with SIZE bits. */
2123 add_standard_iv_candidates_for_size (struct ivopts_data *data,
2126 tree type = lang_hooks.types.type_for_size (size, true);
2127 add_candidate (data, build_int_cst (type, 0), build_int_cst (type, 1),
2131 /* Adds standard iv candidates. */
2134 add_standard_iv_candidates (struct ivopts_data *data)
2136 add_standard_iv_candidates_for_size (data, INT_TYPE_SIZE);
2138 /* The same for a double-integer type if it is still fast enough. */
2139 if (BITS_PER_WORD >= INT_TYPE_SIZE * 2)
2140 add_standard_iv_candidates_for_size (data, INT_TYPE_SIZE * 2);
2144 /* Adds candidates bases on the old induction variable IV. */
2147 add_old_iv_candidates (struct ivopts_data *data, struct iv *iv)
2150 struct iv_cand *cand;
2152 add_candidate (data, iv->base, iv->step, true, NULL);
2154 /* The same, but with initial value zero. */
2155 add_candidate (data,
2156 build_int_cst (TREE_TYPE (iv->base), 0),
2157 iv->step, true, NULL);
2159 phi = SSA_NAME_DEF_STMT (iv->ssa_name);
2160 if (TREE_CODE (phi) == PHI_NODE)
2162 /* Additionally record the possibility of leaving the original iv
2164 def = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (data->current_loop));
2165 cand = add_candidate_1 (data,
2166 iv->base, iv->step, true, IP_ORIGINAL, NULL,
2167 SSA_NAME_DEF_STMT (def));
2168 cand->var_before = iv->ssa_name;
2169 cand->var_after = def;
2173 /* Adds candidates based on the old induction variables. */
2176 add_old_ivs_candidates (struct ivopts_data *data)
2182 EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
2184 iv = ver_info (data, i)->iv;
2185 if (iv && iv->biv_p && !zero_p (iv->step))
2186 add_old_iv_candidates (data, iv);
2190 /* Adds candidates based on the value of the induction variable IV and USE. */
2193 add_iv_value_candidates (struct ivopts_data *data,
2194 struct iv *iv, struct iv_use *use)
2196 unsigned HOST_WIDE_INT offset;
2199 add_candidate (data, iv->base, iv->step, false, use);
2201 /* The same, but with initial value zero. Make such variable important,
2202 since it is generic enough so that possibly many uses may be based
2204 add_candidate (data, build_int_cst (TREE_TYPE (iv->base), 0),
2205 iv->step, true, use);
2207 /* Third, try removing the constant offset. */
2208 base = strip_offset (iv->base, &offset);
2210 add_candidate (data, base, iv->step, false, use);
2213 /* Possibly adds pseudocandidate for replacing the final value of USE by
2214 a direct computation. */
2217 add_iv_outer_candidates (struct ivopts_data *data, struct iv_use *use)
2219 struct tree_niter_desc *niter;
2221 /* We must know where we exit the loop and how many times does it roll. */
2222 niter = niter_for_single_dom_exit (data);
2224 || !zero_p (niter->may_be_zero))
2227 add_candidate_1 (data, NULL, NULL, false, IP_NORMAL, use, NULL_TREE);
2230 /* Adds candidates based on the uses. */
2233 add_derived_ivs_candidates (struct ivopts_data *data)
2237 for (i = 0; i < n_iv_uses (data); i++)
2239 struct iv_use *use = iv_use (data, i);
2246 case USE_NONLINEAR_EXPR:
2249 /* Just add the ivs based on the value of the iv used here. */
2250 add_iv_value_candidates (data, use->iv, use);
2254 add_iv_value_candidates (data, use->iv, use);
2256 /* Additionally, add the pseudocandidate for the possibility to
2257 replace the final value by a direct computation. */
2258 add_iv_outer_candidates (data, use);
2267 /* Record important candidates and add them to related_cands bitmaps
2271 record_important_candidates (struct ivopts_data *data)
2276 for (i = 0; i < n_iv_cands (data); i++)
2278 struct iv_cand *cand = iv_cand (data, i);
2280 if (cand->important)
2281 bitmap_set_bit (data->important_candidates, i);
2284 data->consider_all_candidates = (n_iv_cands (data)
2285 <= CONSIDER_ALL_CANDIDATES_BOUND);
2287 if (data->consider_all_candidates)
2289 /* We will not need "related_cands" bitmaps in this case,
2290 so release them to decrease peak memory consumption. */
2291 for (i = 0; i < n_iv_uses (data); i++)
2293 use = iv_use (data, i);
2294 BITMAP_FREE (use->related_cands);
2299 /* Add important candidates to the related_cands bitmaps. */
2300 for (i = 0; i < n_iv_uses (data); i++)
2301 bitmap_ior_into (iv_use (data, i)->related_cands,
2302 data->important_candidates);
2306 /* Finds the candidates for the induction variables. */
2309 find_iv_candidates (struct ivopts_data *data)
2311 /* Add commonly used ivs. */
2312 add_standard_iv_candidates (data);
2314 /* Add old induction variables. */
2315 add_old_ivs_candidates (data);
2317 /* Add induction variables derived from uses. */
2318 add_derived_ivs_candidates (data);
2320 /* Record the important candidates. */
2321 record_important_candidates (data);
2324 /* Allocates the data structure mapping the (use, candidate) pairs to costs.
2325 If consider_all_candidates is true, we use a two-dimensional array, otherwise
2326 we allocate a simple list to every use. */
2329 alloc_use_cost_map (struct ivopts_data *data)
2331 unsigned i, size, s, j;
2333 for (i = 0; i < n_iv_uses (data); i++)
2335 struct iv_use *use = iv_use (data, i);
2338 if (data->consider_all_candidates)
2339 size = n_iv_cands (data);
2343 EXECUTE_IF_SET_IN_BITMAP (use->related_cands, 0, j, bi)
2348 /* Round up to the power of two, so that moduling by it is fast. */
2349 for (size = 1; size < s; size <<= 1)
2353 use->n_map_members = size;
2354 use->cost_map = xcalloc (size, sizeof (struct cost_pair));
2358 /* Sets cost of (USE, CANDIDATE) pair to COST and record that it depends
2359 on invariants DEPENDS_ON and that the value used in expressing it
2363 set_use_iv_cost (struct ivopts_data *data,
2364 struct iv_use *use, struct iv_cand *cand, unsigned cost,
2365 bitmap depends_on, tree value)
2371 BITMAP_FREE (depends_on);
2375 if (data->consider_all_candidates)
2377 use->cost_map[cand->id].cand = cand;
2378 use->cost_map[cand->id].cost = cost;
2379 use->cost_map[cand->id].depends_on = depends_on;
2380 use->cost_map[cand->id].value = value;
2384 /* n_map_members is a power of two, so this computes modulo. */
2385 s = cand->id & (use->n_map_members - 1);
2386 for (i = s; i < use->n_map_members; i++)
2387 if (!use->cost_map[i].cand)
2389 for (i = 0; i < s; i++)
2390 if (!use->cost_map[i].cand)
2396 use->cost_map[i].cand = cand;
2397 use->cost_map[i].cost = cost;
2398 use->cost_map[i].depends_on = depends_on;
2399 use->cost_map[i].value = value;
2402 /* Gets cost of (USE, CANDIDATE) pair. */
2404 static struct cost_pair *
2405 get_use_iv_cost (struct ivopts_data *data, struct iv_use *use,
2406 struct iv_cand *cand)
2409 struct cost_pair *ret;
2414 if (data->consider_all_candidates)
2416 ret = use->cost_map + cand->id;
2423 /* n_map_members is a power of two, so this computes modulo. */
2424 s = cand->id & (use->n_map_members - 1);
2425 for (i = s; i < use->n_map_members; i++)
2426 if (use->cost_map[i].cand == cand)
2427 return use->cost_map + i;
2429 for (i = 0; i < s; i++)
2430 if (use->cost_map[i].cand == cand)
2431 return use->cost_map + i;
2436 /* Returns estimate on cost of computing SEQ. */
2444 for (; seq; seq = NEXT_INSN (seq))
2446 set = single_set (seq);
2448 cost += rtx_cost (set, SET);
2456 /* Produce DECL_RTL for object obj so it looks like it is stored in memory. */
2458 produce_memory_decl_rtl (tree obj, int *regno)
2463 if (TREE_STATIC (obj) || DECL_EXTERNAL (obj))
2465 const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (obj));
2466 x = gen_rtx_SYMBOL_REF (Pmode, name);
2469 x = gen_raw_REG (Pmode, (*regno)++);
2471 return gen_rtx_MEM (DECL_MODE (obj), x);
2474 /* Prepares decl_rtl for variables referred in *EXPR_P. Callback for
2475 walk_tree. DATA contains the actual fake register number. */
2478 prepare_decl_rtl (tree *expr_p, int *ws, void *data)
2480 tree obj = NULL_TREE;
2484 switch (TREE_CODE (*expr_p))
2487 for (expr_p = &TREE_OPERAND (*expr_p, 0);
2488 handled_component_p (*expr_p);
2489 expr_p = &TREE_OPERAND (*expr_p, 0))
2493 x = produce_memory_decl_rtl (obj, regno);
2498 obj = SSA_NAME_VAR (*expr_p);
2499 if (!DECL_RTL_SET_P (obj))
2500 x = gen_raw_REG (DECL_MODE (obj), (*regno)++);
2509 if (DECL_RTL_SET_P (obj))
2512 if (DECL_MODE (obj) == BLKmode)
2513 x = produce_memory_decl_rtl (obj, regno);
2515 x = gen_raw_REG (DECL_MODE (obj), (*regno)++);
2525 VEC_safe_push (tree, heap, decl_rtl_to_reset, obj);
2526 SET_DECL_RTL (obj, x);
2532 /* Determines cost of the computation of EXPR. */
2535 computation_cost (tree expr)
2538 tree type = TREE_TYPE (expr);
2540 /* Avoid using hard regs in ways which may be unsupported. */
2541 int regno = LAST_VIRTUAL_REGISTER + 1;
2543 walk_tree (&expr, prepare_decl_rtl, ®no, NULL);
2545 rslt = expand_expr (expr, NULL_RTX, TYPE_MODE (type), EXPAND_NORMAL);
2549 cost = seq_cost (seq);
2551 cost += address_cost (XEXP (rslt, 0), TYPE_MODE (type));
2556 /* Returns variable containing the value of candidate CAND at statement AT. */
2559 var_at_stmt (struct loop *loop, struct iv_cand *cand, tree stmt)
2561 if (stmt_after_increment (loop, cand, stmt))
2562 return cand->var_after;
2564 return cand->var_before;
2567 /* Return the most significant (sign) bit of T. Similar to tree_int_cst_msb,
2568 but the bit is determined from TYPE_PRECISION, not MODE_BITSIZE. */
2571 tree_int_cst_sign_bit (tree t)
2573 unsigned bitno = TYPE_PRECISION (TREE_TYPE (t)) - 1;
2574 unsigned HOST_WIDE_INT w;
2576 if (bitno < HOST_BITS_PER_WIDE_INT)
2577 w = TREE_INT_CST_LOW (t);
2580 w = TREE_INT_CST_HIGH (t);
2581 bitno -= HOST_BITS_PER_WIDE_INT;
2584 return (w >> bitno) & 1;
2587 /* If we can prove that TOP = cst * BOT for some constant cst in TYPE,
2588 return cst. Otherwise return NULL_TREE. */
2591 constant_multiple_of (tree type, tree top, tree bot)
2593 tree res, mby, p0, p1;
2594 enum tree_code code;
2600 if (operand_equal_p (top, bot, 0))
2601 return build_int_cst (type, 1);
2603 code = TREE_CODE (top);
2607 mby = TREE_OPERAND (top, 1);
2608 if (TREE_CODE (mby) != INTEGER_CST)
2611 res = constant_multiple_of (type, TREE_OPERAND (top, 0), bot);
2615 return fold_binary_to_constant (MULT_EXPR, type, res,
2616 fold_convert (type, mby));
2620 p0 = constant_multiple_of (type, TREE_OPERAND (top, 0), bot);
2623 p1 = constant_multiple_of (type, TREE_OPERAND (top, 1), bot);
2627 return fold_binary_to_constant (code, type, p0, p1);
2630 if (TREE_CODE (bot) != INTEGER_CST)
2633 bot = fold_convert (type, bot);
2634 top = fold_convert (type, top);
2636 /* If BOT seems to be negative, try dividing by -BOT instead, and negate
2637 the result afterwards. */
2638 if (tree_int_cst_sign_bit (bot))
2641 bot = fold_unary_to_constant (NEGATE_EXPR, type, bot);
2646 /* Ditto for TOP. */
2647 if (tree_int_cst_sign_bit (top))
2650 top = fold_unary_to_constant (NEGATE_EXPR, type, top);
2653 if (!zero_p (fold_binary_to_constant (TRUNC_MOD_EXPR, type, top, bot)))
2656 res = fold_binary_to_constant (EXACT_DIV_EXPR, type, top, bot);
2658 res = fold_unary_to_constant (NEGATE_EXPR, type, res);
2666 /* Sets COMB to CST. */
2669 aff_combination_const (struct affine_tree_combination *comb, tree type,
2670 unsigned HOST_WIDE_INT cst)
2672 unsigned prec = TYPE_PRECISION (type);
2675 comb->mask = (((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1);
2678 comb->rest = NULL_TREE;
2679 comb->offset = cst & comb->mask;
2682 /* Sets COMB to single element ELT. */
2685 aff_combination_elt (struct affine_tree_combination *comb, tree type, tree elt)
2687 unsigned prec = TYPE_PRECISION (type);
2690 comb->mask = (((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1);
2693 comb->elts[0] = elt;
2695 comb->rest = NULL_TREE;
2699 /* Scales COMB by SCALE. */
2702 aff_combination_scale (struct affine_tree_combination *comb,
2703 unsigned HOST_WIDE_INT scale)
2712 aff_combination_const (comb, comb->type, 0);
2716 comb->offset = (scale * comb->offset) & comb->mask;
2717 for (i = 0, j = 0; i < comb->n; i++)
2719 comb->coefs[j] = (scale * comb->coefs[i]) & comb->mask;
2720 comb->elts[j] = comb->elts[i];
2721 if (comb->coefs[j] != 0)
2728 if (comb->n < MAX_AFF_ELTS)
2730 comb->coefs[comb->n] = scale;
2731 comb->elts[comb->n] = comb->rest;
2732 comb->rest = NULL_TREE;
2736 comb->rest = fold_build2 (MULT_EXPR, comb->type, comb->rest,
2737 build_int_cst_type (comb->type, scale));
2741 /* Adds ELT * SCALE to COMB. */
2744 aff_combination_add_elt (struct affine_tree_combination *comb, tree elt,
2745 unsigned HOST_WIDE_INT scale)
2752 for (i = 0; i < comb->n; i++)
2753 if (operand_equal_p (comb->elts[i], elt, 0))
2755 comb->coefs[i] = (comb->coefs[i] + scale) & comb->mask;
2760 comb->coefs[i] = comb->coefs[comb->n];
2761 comb->elts[i] = comb->elts[comb->n];
2764 if (comb->n < MAX_AFF_ELTS)
2766 comb->coefs[comb->n] = scale;
2767 comb->elts[comb->n] = elt;
2773 elt = fold_convert (comb->type, elt);
2775 elt = fold_build2 (MULT_EXPR, comb->type,
2776 fold_convert (comb->type, elt),
2777 build_int_cst_type (comb->type, scale));
2780 comb->rest = fold_build2 (PLUS_EXPR, comb->type, comb->rest, elt);
2785 /* Adds COMB2 to COMB1. */
2788 aff_combination_add (struct affine_tree_combination *comb1,
2789 struct affine_tree_combination *comb2)
2793 comb1->offset = (comb1->offset + comb2->offset) & comb1->mask;
2794 for (i = 0; i < comb2-> n; i++)
2795 aff_combination_add_elt (comb1, comb2->elts[i], comb2->coefs[i]);
2797 aff_combination_add_elt (comb1, comb2->rest, 1);
2800 /* Splits EXPR into an affine combination of parts. */
2803 tree_to_aff_combination (tree expr, tree type,
2804 struct affine_tree_combination *comb)
2806 struct affine_tree_combination tmp;
2807 enum tree_code code;
2808 tree cst, core, toffset;
2809 HOST_WIDE_INT bitpos, bitsize;
2810 enum machine_mode mode;
2811 int unsignedp, volatilep;
2815 code = TREE_CODE (expr);
2819 aff_combination_const (comb, type, int_cst_value (expr));
2824 tree_to_aff_combination (TREE_OPERAND (expr, 0), type, comb);
2825 tree_to_aff_combination (TREE_OPERAND (expr, 1), type, &tmp);
2826 if (code == MINUS_EXPR)
2827 aff_combination_scale (&tmp, -1);
2828 aff_combination_add (comb, &tmp);
2832 cst = TREE_OPERAND (expr, 1);
2833 if (TREE_CODE (cst) != INTEGER_CST)
2835 tree_to_aff_combination (TREE_OPERAND (expr, 0), type, comb);
2836 aff_combination_scale (comb, int_cst_value (cst));
2840 tree_to_aff_combination (TREE_OPERAND (expr, 0), type, comb);
2841 aff_combination_scale (comb, -1);
2845 core = get_inner_reference (TREE_OPERAND (expr, 0), &bitsize, &bitpos,
2846 &toffset, &mode, &unsignedp, &volatilep,
2848 if (bitpos % BITS_PER_UNIT != 0)
2850 aff_combination_const (comb, type, bitpos / BITS_PER_UNIT);
2851 core = build_fold_addr_expr (core);
2852 if (TREE_CODE (core) == ADDR_EXPR)
2853 aff_combination_add_elt (comb, core, 1);
2856 tree_to_aff_combination (core, type, &tmp);
2857 aff_combination_add (comb, &tmp);
2861 tree_to_aff_combination (toffset, type, &tmp);
2862 aff_combination_add (comb, &tmp);
2870 aff_combination_elt (comb, type, expr);
2873 /* Creates EXPR + ELT * SCALE in TYPE. MASK is the mask for width of TYPE. */
2876 add_elt_to_tree (tree expr, tree type, tree elt, unsigned HOST_WIDE_INT scale,
2877 unsigned HOST_WIDE_INT mask)
2879 enum tree_code code;
2882 elt = fold_convert (type, elt);
2889 return fold_build2 (PLUS_EXPR, type, expr, elt);
2895 return fold_build1 (NEGATE_EXPR, type, elt);
2897 return fold_build2 (MINUS_EXPR, type, expr, elt);
2901 return fold_build2 (MULT_EXPR, type, elt,
2902 build_int_cst_type (type, scale));
2904 if ((scale | (mask >> 1)) == mask)
2906 /* Scale is negative. */
2908 scale = (-scale) & mask;
2913 elt = fold_build2 (MULT_EXPR, type, elt,
2914 build_int_cst_type (type, scale));
2915 return fold_build2 (code, type, expr, elt);
2918 /* Copies the tree elements of COMB to ensure that they are not shared. */
2921 unshare_aff_combination (struct affine_tree_combination *comb)
2925 for (i = 0; i < comb->n; i++)
2926 comb->elts[i] = unshare_expr (comb->elts[i]);
2928 comb->rest = unshare_expr (comb->rest);
2931 /* Makes tree from the affine combination COMB. */
2934 aff_combination_to_tree (struct affine_tree_combination *comb)
2936 tree type = comb->type;
2937 tree expr = comb->rest;
2939 unsigned HOST_WIDE_INT off, sgn;
2941 /* Handle the special case produced by get_computation_aff when
2942 the type does not fit in HOST_WIDE_INT. */
2943 if (comb->n == 0 && comb->offset == 0)
2944 return fold_convert (type, expr);
2946 gcc_assert (comb->n == MAX_AFF_ELTS || comb->rest == NULL_TREE);
2948 for (i = 0; i < comb->n; i++)
2949 expr = add_elt_to_tree (expr, type, comb->elts[i], comb->coefs[i],
2952 if ((comb->offset | (comb->mask >> 1)) == comb->mask)
2954 /* Offset is negative. */
2955 off = (-comb->offset) & comb->mask;
2963 return add_elt_to_tree (expr, type, build_int_cst_type (type, off), sgn,
2967 /* Determines the expression by that USE is expressed from induction variable
2968 CAND at statement AT in LOOP. The expression is stored in a decomposed
2969 form into AFF. Returns false if USE cannot be expressed using CAND. */
2972 get_computation_aff (struct loop *loop,
2973 struct iv_use *use, struct iv_cand *cand, tree at,
2974 struct affine_tree_combination *aff)
2976 tree ubase = use->iv->base;
2977 tree ustep = use->iv->step;
2978 tree cbase = cand->iv->base;
2979 tree cstep = cand->iv->step;
2980 tree utype = TREE_TYPE (ubase), ctype = TREE_TYPE (cbase);
2984 unsigned HOST_WIDE_INT ustepi, cstepi;
2985 HOST_WIDE_INT ratioi;
2986 struct affine_tree_combination cbase_aff, expr_aff;
2987 tree cstep_orig = cstep, ustep_orig = ustep;
2989 if (TYPE_PRECISION (utype) > TYPE_PRECISION (ctype))
2991 /* We do not have a precision to express the values of use. */
2995 expr = var_at_stmt (loop, cand, at);
2997 if (TREE_TYPE (expr) != ctype)
2999 /* This may happen with the original ivs. */
3000 expr = fold_convert (ctype, expr);
3003 if (TYPE_UNSIGNED (utype))
3007 uutype = unsigned_type_for (utype);
3008 ubase = fold_convert (uutype, ubase);
3009 ustep = fold_convert (uutype, ustep);
3012 if (uutype != ctype)
3014 expr = fold_convert (uutype, expr);
3015 cbase = fold_convert (uutype, cbase);
3016 cstep = fold_convert (uutype, cstep);
3018 /* If the conversion is not noop, we must take it into account when
3019 considering the value of the step. */
3020 if (TYPE_PRECISION (utype) < TYPE_PRECISION (ctype))
3024 if (cst_and_fits_in_hwi (cstep_orig)
3025 && cst_and_fits_in_hwi (ustep_orig))
3027 ustepi = int_cst_value (ustep_orig);
3028 cstepi = int_cst_value (cstep_orig);
3030 if (!divide (TYPE_PRECISION (uutype), ustepi, cstepi, &ratioi))
3032 /* TODO maybe consider case when ustep divides cstep and the ratio is
3033 a power of 2 (so that the division is fast to execute)? We would
3034 need to be much more careful with overflows etc. then. */
3038 ratio = build_int_cst_type (uutype, ratioi);
3042 ratio = constant_multiple_of (uutype, ustep_orig, cstep_orig);
3046 /* Ratioi is only used to detect special cases when the multiplicative
3047 factor is 1 or -1, so if we cannot convert ratio to HOST_WIDE_INT,
3048 we may set it to 0. We prefer cst_and_fits_in_hwi/int_cst_value
3049 to integer_onep/integer_all_onesp, since the former ignores
3051 if (cst_and_fits_in_hwi (ratio))
3052 ratioi = int_cst_value (ratio);
3053 else if (integer_onep (ratio))
3055 else if (integer_all_onesp (ratio))
3061 /* We may need to shift the value if we are after the increment. */
3062 if (stmt_after_increment (loop, cand, at))
3063 cbase = fold_build2 (PLUS_EXPR, uutype, cbase, cstep);
3065 /* use = ubase - ratio * cbase + ratio * var.
3067 In general case ubase + ratio * (var - cbase) could be better (one less
3068 multiplication), but often it is possible to eliminate redundant parts
3069 of computations from (ubase - ratio * cbase) term, and if it does not
3070 happen, fold is able to apply the distributive law to obtain this form
3073 if (TYPE_PRECISION (uutype) > HOST_BITS_PER_WIDE_INT)
3075 /* Let's compute in trees and just return the result in AFF. This case
3076 should not be very common, and fold itself is not that bad either,
3077 so making the aff. functions more complicated to handle this case
3078 is not that urgent. */
3081 delta = fold_build2 (MINUS_EXPR, uutype, ubase, cbase);
3082 expr = fold_build2 (PLUS_EXPR, uutype, expr, delta);
3084 else if (ratioi == -1)
3086 delta = fold_build2 (PLUS_EXPR, uutype, ubase, cbase);
3087 expr = fold_build2 (MINUS_EXPR, uutype, delta, expr);
3091 delta = fold_build2 (MULT_EXPR, uutype, cbase, ratio);
3092 delta = fold_build2 (MINUS_EXPR, uutype, ubase, delta);
3093 expr = fold_build2 (MULT_EXPR, uutype, ratio, expr);
3094 expr = fold_build2 (PLUS_EXPR, uutype, delta, expr);
3105 /* If we got here, the types fits in HOST_WIDE_INT, thus it must be
3106 possible to compute ratioi. */
3107 gcc_assert (ratioi);
3109 tree_to_aff_combination (ubase, uutype, aff);
3110 tree_to_aff_combination (cbase, uutype, &cbase_aff);
3111 tree_to_aff_combination (expr, uutype, &expr_aff);
3112 aff_combination_scale (&cbase_aff, -ratioi);
3113 aff_combination_scale (&expr_aff, ratioi);
3114 aff_combination_add (aff, &cbase_aff);
3115 aff_combination_add (aff, &expr_aff);
3120 /* Determines the expression by that USE is expressed from induction variable
3121 CAND at statement AT in LOOP. The computation is unshared. */
3124 get_computation_at (struct loop *loop,
3125 struct iv_use *use, struct iv_cand *cand, tree at)
3127 struct affine_tree_combination aff;
3128 tree type = TREE_TYPE (use->iv->base);
3130 if (!get_computation_aff (loop, use, cand, at, &aff))
3132 unshare_aff_combination (&aff);
3133 return fold_convert (type, aff_combination_to_tree (&aff));
3136 /* Determines the expression by that USE is expressed from induction variable
3137 CAND in LOOP. The computation is unshared. */
3140 get_computation (struct loop *loop, struct iv_use *use, struct iv_cand *cand)
3142 return get_computation_at (loop, use, cand, use->stmt);
3145 /* Returns cost of addition in MODE. */
3148 add_cost (enum machine_mode mode)
3150 static unsigned costs[NUM_MACHINE_MODES];
3158 force_operand (gen_rtx_fmt_ee (PLUS, mode,
3159 gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 1),
3160 gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 2)),
3165 cost = seq_cost (seq);
3171 if (dump_file && (dump_flags & TDF_DETAILS))
3172 fprintf (dump_file, "Addition in %s costs %d\n",
3173 GET_MODE_NAME (mode), cost);
3177 /* Entry in a hashtable of already known costs for multiplication. */
3180 HOST_WIDE_INT cst; /* The constant to multiply by. */
3181 enum machine_mode mode; /* In mode. */
3182 unsigned cost; /* The cost. */
3185 /* Counts hash value for the ENTRY. */
3188 mbc_entry_hash (const void *entry)
3190 const struct mbc_entry *e = entry;
3192 return 57 * (hashval_t) e->mode + (hashval_t) (e->cst % 877);
3195 /* Compares the hash table entries ENTRY1 and ENTRY2. */
3198 mbc_entry_eq (const void *entry1, const void *entry2)
3200 const struct mbc_entry *e1 = entry1;
3201 const struct mbc_entry *e2 = entry2;
3203 return (e1->mode == e2->mode
3204 && e1->cst == e2->cst);
3207 /* Returns cost of multiplication by constant CST in MODE. */
3210 multiply_by_cost (HOST_WIDE_INT cst, enum machine_mode mode)
3212 static htab_t costs;
3213 struct mbc_entry **cached, act;
3218 costs = htab_create (100, mbc_entry_hash, mbc_entry_eq, free);
3222 cached = (struct mbc_entry **) htab_find_slot (costs, &act, INSERT);
3224 return (*cached)->cost;
3226 *cached = xmalloc (sizeof (struct mbc_entry));
3227 (*cached)->mode = mode;
3228 (*cached)->cst = cst;
3231 expand_mult (mode, gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 1),
3232 gen_int_mode (cst, mode), NULL_RTX, 0);
3236 cost = seq_cost (seq);
3238 if (dump_file && (dump_flags & TDF_DETAILS))
3239 fprintf (dump_file, "Multiplication by %d in %s costs %d\n",
3240 (int) cst, GET_MODE_NAME (mode), cost);
3242 (*cached)->cost = cost;
3247 /* Returns true if multiplying by RATIO is allowed in address. */
3250 multiplier_allowed_in_address_p (HOST_WIDE_INT ratio)
3252 #define MAX_RATIO 128
3253 static sbitmap valid_mult;
3257 rtx reg1 = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1);
3261 valid_mult = sbitmap_alloc (2 * MAX_RATIO + 1);
3262 sbitmap_zero (valid_mult);
3263 addr = gen_rtx_fmt_ee (MULT, Pmode, reg1, NULL_RTX);
3264 for (i = -MAX_RATIO; i <= MAX_RATIO; i++)
3266 XEXP (addr, 1) = gen_int_mode (i, Pmode);
3267 if (memory_address_p (Pmode, addr))
3268 SET_BIT (valid_mult, i + MAX_RATIO);
3271 if (dump_file && (dump_flags & TDF_DETAILS))
3273 fprintf (dump_file, " allowed multipliers:");
3274 for (i = -MAX_RATIO; i <= MAX_RATIO; i++)
3275 if (TEST_BIT (valid_mult, i + MAX_RATIO))
3276 fprintf (dump_file, " %d", (int) i);
3277 fprintf (dump_file, "\n");
3278 fprintf (dump_file, "\n");
3282 if (ratio > MAX_RATIO || ratio < -MAX_RATIO)
3285 return TEST_BIT (valid_mult, ratio + MAX_RATIO);
3288 /* Returns cost of address in shape symbol + var + OFFSET + RATIO * index.
3289 If SYMBOL_PRESENT is false, symbol is omitted. If VAR_PRESENT is false,
3290 variable is omitted. The created memory accesses MODE.
3292 TODO -- there must be some better way. This all is quite crude. */
3295 get_address_cost (bool symbol_present, bool var_present,
3296 unsigned HOST_WIDE_INT offset, HOST_WIDE_INT ratio)
3298 static bool initialized = false;
3299 static HOST_WIDE_INT rat, off;
3300 static HOST_WIDE_INT min_offset, max_offset;
3301 static unsigned costs[2][2][2][2];
3302 unsigned cost, acost;
3303 rtx seq, addr, base;
3304 bool offset_p, ratio_p;
3306 HOST_WIDE_INT s_offset;
3307 unsigned HOST_WIDE_INT mask;
3315 reg1 = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1);
3317 addr = gen_rtx_fmt_ee (PLUS, Pmode, reg1, NULL_RTX);
3318 for (i = 1; i <= 1 << 20; i <<= 1)
3320 XEXP (addr, 1) = gen_int_mode (i, Pmode);
3321 if (!memory_address_p (Pmode, addr))
3324 max_offset = i >> 1;
3327 for (i = 1; i <= 1 << 20; i <<= 1)
3329 XEXP (addr, 1) = gen_int_mode (-i, Pmode);
3330 if (!memory_address_p (Pmode, addr))
3333 min_offset = -(i >> 1);
3335 if (dump_file && (dump_flags & TDF_DETAILS))
3337 fprintf (dump_file, "get_address_cost:\n");
3338 fprintf (dump_file, " min offset %d\n", (int) min_offset);
3339 fprintf (dump_file, " max offset %d\n", (int) max_offset);
3343 for (i = 2; i <= MAX_RATIO; i++)
3344 if (multiplier_allowed_in_address_p (i))
3351 bits = GET_MODE_BITSIZE (Pmode);
3352 mask = ~(~(unsigned HOST_WIDE_INT) 0 << (bits - 1) << 1);
3354 if ((offset >> (bits - 1) & 1))
3359 offset_p = (s_offset != 0
3360 && min_offset <= s_offset && s_offset <= max_offset);
3361 ratio_p = (ratio != 1
3362 && multiplier_allowed_in_address_p (ratio));
3364 if (ratio != 1 && !ratio_p)
3365 cost += multiply_by_cost (ratio, Pmode);
3367 if (s_offset && !offset_p && !symbol_present)
3369 cost += add_cost (Pmode);
3373 acost = costs[symbol_present][var_present][offset_p][ratio_p];
3378 addr = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1);
3379 reg1 = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 2);
3381 addr = gen_rtx_fmt_ee (MULT, Pmode, addr, gen_int_mode (rat, Pmode));
3384 addr = gen_rtx_fmt_ee (PLUS, Pmode, addr, reg1);
3388 base = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (""));
3390 base = gen_rtx_fmt_e (CONST, Pmode,
3391 gen_rtx_fmt_ee (PLUS, Pmode,
3393 gen_int_mode (off, Pmode)));
3396 base = gen_int_mode (off, Pmode);
3401 addr = gen_rtx_fmt_ee (PLUS, Pmode, addr, base);
3404 addr = memory_address (Pmode, addr);
3408 acost = seq_cost (seq);
3409 acost += address_cost (addr, Pmode);
3413 costs[symbol_present][var_present][offset_p][ratio_p] = acost;
3416 return cost + acost;
3418 /* Estimates cost of forcing EXPR into a variable. DEPENDS_ON is a set of the
3419 invariants the computation depends on. */
3422 force_var_cost (struct ivopts_data *data,
3423 tree expr, bitmap *depends_on)
3425 static bool costs_initialized = false;
3426 static unsigned integer_cost;
3427 static unsigned symbol_cost;
3428 static unsigned address_cost;
3430 unsigned cost0, cost1, cost;
3431 enum machine_mode mode;
3433 if (!costs_initialized)
3435 tree var = create_tmp_var_raw (integer_type_node, "test_var");
3436 rtx x = gen_rtx_MEM (DECL_MODE (var),
3437 gen_rtx_SYMBOL_REF (Pmode, "test_var"));
3439 tree type = build_pointer_type (integer_type_node);
3441 integer_cost = computation_cost (build_int_cst_type (integer_type_node,
3444 SET_DECL_RTL (var, x);
3445 TREE_STATIC (var) = 1;
3446 addr = build1 (ADDR_EXPR, type, var);
3447 symbol_cost = computation_cost (addr) + 1;
3450 = computation_cost (build2 (PLUS_EXPR, type,
3452 build_int_cst_type (type, 2000))) + 1;
3453 if (dump_file && (dump_flags & TDF_DETAILS))
3455 fprintf (dump_file, "force_var_cost:\n");
3456 fprintf (dump_file, " integer %d\n", (int) integer_cost);
3457 fprintf (dump_file, " symbol %d\n", (int) symbol_cost);
3458 fprintf (dump_file, " address %d\n", (int) address_cost);
3459 fprintf (dump_file, " other %d\n", (int) target_spill_cost);
3460 fprintf (dump_file, "\n");
3463 costs_initialized = true;
3470 fd_ivopts_data = data;
3471 walk_tree (&expr, find_depends, depends_on, NULL);
3474 if (SSA_VAR_P (expr))
3477 if (TREE_INVARIANT (expr))
3479 if (TREE_CODE (expr) == INTEGER_CST)
3480 return integer_cost;
3482 if (TREE_CODE (expr) == ADDR_EXPR)
3484 tree obj = TREE_OPERAND (expr, 0);
3486 if (TREE_CODE (obj) == VAR_DECL
3487 || TREE_CODE (obj) == PARM_DECL
3488 || TREE_CODE (obj) == RESULT_DECL)
3492 return address_cost;
3495 switch (TREE_CODE (expr))
3500 op0 = TREE_OPERAND (expr, 0);
3501 op1 = TREE_OPERAND (expr, 1);
3505 if (is_gimple_val (op0))
3508 cost0 = force_var_cost (data, op0, NULL);
3510 if (is_gimple_val (op1))
3513 cost1 = force_var_cost (data, op1, NULL);
3518 /* Just an arbitrary value, FIXME. */
3519 return target_spill_cost;
3522 mode = TYPE_MODE (TREE_TYPE (expr));
3523 switch (TREE_CODE (expr))
3527 cost = add_cost (mode);
3531 if (cst_and_fits_in_hwi (op0))
3532 cost = multiply_by_cost (int_cst_value (op0), mode);
3533 else if (cst_and_fits_in_hwi (op1))
3534 cost = multiply_by_cost (int_cst_value (op1), mode);
3536 return target_spill_cost;
3546 /* Bound the cost by target_spill_cost. The parts of complicated
3547 computations often are either loop invariant or at least can
3548 be shared between several iv uses, so letting this grow without
3549 limits would not give reasonable results. */
3550 return cost < target_spill_cost ? cost : target_spill_cost;
3553 /* Estimates cost of expressing address ADDR as var + symbol + offset. The
3554 value of offset is added to OFFSET, SYMBOL_PRESENT and VAR_PRESENT are set
3555 to false if the corresponding part is missing. DEPENDS_ON is a set of the
3556 invariants the computation depends on. */
3559 split_address_cost (struct ivopts_data *data,
3560 tree addr, bool *symbol_present, bool *var_present,
3561 unsigned HOST_WIDE_INT *offset, bitmap *depends_on)
3564 HOST_WIDE_INT bitsize;
3565 HOST_WIDE_INT bitpos;
3567 enum machine_mode mode;
3568 int unsignedp, volatilep;
3570 core = get_inner_reference (addr, &bitsize, &bitpos, &toffset, &mode,
3571 &unsignedp, &volatilep, false);
3574 || bitpos % BITS_PER_UNIT != 0
3575 || TREE_CODE (core) != VAR_DECL)
3577 *symbol_present = false;
3578 *var_present = true;
3579 fd_ivopts_data = data;
3580 walk_tree (&addr, find_depends, depends_on, NULL);
3581 return target_spill_cost;
3584 *offset += bitpos / BITS_PER_UNIT;
3585 if (TREE_STATIC (core)
3586 || DECL_EXTERNAL (core))
3588 *symbol_present = true;
3589 *var_present = false;
3593 *symbol_present = false;
3594 *var_present = true;
3598 /* Estimates cost of expressing difference of addresses E1 - E2 as
3599 var + symbol + offset. The value of offset is added to OFFSET,
3600 SYMBOL_PRESENT and VAR_PRESENT are set to false if the corresponding
3601 part is missing. DEPENDS_ON is a set of the invariants the computation
3605 ptr_difference_cost (struct ivopts_data *data,
3606 tree e1, tree e2, bool *symbol_present, bool *var_present,
3607 unsigned HOST_WIDE_INT *offset, bitmap *depends_on)
3609 HOST_WIDE_INT diff = 0;
3612 gcc_assert (TREE_CODE (e1) == ADDR_EXPR);
3614 if (ptr_difference_const (e1, e2, &diff))
3617 *symbol_present = false;
3618 *var_present = false;
3622 if (e2 == integer_zero_node)
3623 return split_address_cost (data, TREE_OPERAND (e1, 0),
3624 symbol_present, var_present, offset, depends_on);
3626 *symbol_present = false;
3627 *var_present = true;
3629 cost = force_var_cost (data, e1, depends_on);
3630 cost += force_var_cost (data, e2, depends_on);
3631 cost += add_cost (Pmode);
3636 /* Estimates cost of expressing difference E1 - E2 as
3637 var + symbol + offset. The value of offset is added to OFFSET,
3638 SYMBOL_PRESENT and VAR_PRESENT are set to false if the corresponding
3639 part is missing. DEPENDS_ON is a set of the invariants the computation
3643 difference_cost (struct ivopts_data *data,
3644 tree e1, tree e2, bool *symbol_present, bool *var_present,
3645 unsigned HOST_WIDE_INT *offset, bitmap *depends_on)
3648 enum machine_mode mode = TYPE_MODE (TREE_TYPE (e1));
3649 unsigned HOST_WIDE_INT off1, off2;
3651 e1 = strip_offset (e1, &off1);
3652 e2 = strip_offset (e2, &off2);
3653 *offset += off1 - off2;
3658 if (TREE_CODE (e1) == ADDR_EXPR)
3659 return ptr_difference_cost (data, e1, e2, symbol_present, var_present, offset,
3661 *symbol_present = false;
3663 if (operand_equal_p (e1, e2, 0))
3665 *var_present = false;
3668 *var_present = true;
3670 return force_var_cost (data, e1, depends_on);
3674 cost = force_var_cost (data, e2, depends_on);
3675 cost += multiply_by_cost (-1, mode);
3680 cost = force_var_cost (data, e1, depends_on);
3681 cost += force_var_cost (data, e2, depends_on);
3682 cost += add_cost (mode);
3687 /* Determines the cost of the computation by that USE is expressed
3688 from induction variable CAND. If ADDRESS_P is true, we just need
3689 to create an address from it, otherwise we want to get it into
3690 register. A set of invariants we depend on is stored in
3691 DEPENDS_ON. AT is the statement at that the value is computed. */
3694 get_computation_cost_at (struct ivopts_data *data,
3695 struct iv_use *use, struct iv_cand *cand,
3696 bool address_p, bitmap *depends_on, tree at)
3698 tree ubase = use->iv->base, ustep = use->iv->step;
3700 tree utype = TREE_TYPE (ubase), ctype;
3701 unsigned HOST_WIDE_INT ustepi, cstepi, offset = 0;
3702 HOST_WIDE_INT ratio, aratio;
3703 bool var_present, symbol_present;
3704 unsigned cost = 0, n_sums;
3708 /* Only consider real candidates. */
3712 cbase = cand->iv->base;
3713 cstep = cand->iv->step;
3714 ctype = TREE_TYPE (cbase);
3716 if (TYPE_PRECISION (utype) > TYPE_PRECISION (ctype))
3718 /* We do not have a precision to express the values of use. */
3724 /* Do not try to express address of an object with computation based
3725 on address of a different object. This may cause problems in rtl
3726 level alias analysis (that does not expect this to be happening,
3727 as this is illegal in C), and would be unlikely to be useful
3729 if (use->iv->base_object
3730 && cand->iv->base_object
3731 && !operand_equal_p (use->iv->base_object, cand->iv->base_object, 0))
3735 if (TYPE_PRECISION (utype) != TYPE_PRECISION (ctype))
3737 /* TODO -- add direct handling of this case. */
3741 /* CSTEPI is removed from the offset in case statement is after the
3742 increment. If the step is not constant, we use zero instead.
3743 This is a bit imprecise (there is the extra addition), but
3744 redundancy elimination is likely to transform the code so that
3745 it uses value of the variable before increment anyway,
3746 so it is not that much unrealistic. */
3747 if (cst_and_fits_in_hwi (cstep))
3748 cstepi = int_cst_value (cstep);
3752 if (cst_and_fits_in_hwi (ustep)
3753 && cst_and_fits_in_hwi (cstep))
3755 ustepi = int_cst_value (ustep);
3757 if (!divide (TYPE_PRECISION (utype), ustepi, cstepi, &ratio))
3764 rat = constant_multiple_of (utype, ustep, cstep);
3769 if (cst_and_fits_in_hwi (rat))
3770 ratio = int_cst_value (rat);
3771 else if (integer_onep (rat))
3773 else if (integer_all_onesp (rat))
3779 /* use = ubase + ratio * (var - cbase). If either cbase is a constant
3780 or ratio == 1, it is better to handle this like
3782 ubase - ratio * cbase + ratio * var
3784 (also holds in the case ratio == -1, TODO. */
3786 if (cst_and_fits_in_hwi (cbase))
3788 offset = - ratio * int_cst_value (cbase);
3789 cost += difference_cost (data,
3790 ubase, integer_zero_node,
3791 &symbol_present, &var_present, &offset,
3794 else if (ratio == 1)
3796 cost += difference_cost (data,
3798 &symbol_present, &var_present, &offset,
3803 cost += force_var_cost (data, cbase, depends_on);
3804 cost += add_cost (TYPE_MODE (ctype));
3805 cost += difference_cost (data,
3806 ubase, integer_zero_node,
3807 &symbol_present, &var_present, &offset,
3811 /* If we are after the increment, the value of the candidate is higher by
3813 if (stmt_after_increment (data->current_loop, cand, at))
3814 offset -= ratio * cstepi;
3816 /* Now the computation is in shape symbol + var1 + const + ratio * var2.
3817 (symbol/var/const parts may be omitted). If we are looking for an address,
3818 find the cost of addressing this. */
3820 return cost + get_address_cost (symbol_present, var_present, offset, ratio);
3822 /* Otherwise estimate the costs for computing the expression. */
3823 aratio = ratio > 0 ? ratio : -ratio;
3824 if (!symbol_present && !var_present && !offset)
3827 cost += multiply_by_cost (ratio, TYPE_MODE (ctype));
3833 cost += multiply_by_cost (aratio, TYPE_MODE (ctype));
3837 /* Symbol + offset should be compile-time computable. */
3838 && (symbol_present || offset))
3841 return cost + n_sums * add_cost (TYPE_MODE (ctype));
3845 /* Just get the expression, expand it and measure the cost. */
3846 tree comp = get_computation_at (data->current_loop, use, cand, at);
3852 comp = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (comp)), comp);
3854 return computation_cost (comp);
3858 /* Determines the cost of the computation by that USE is expressed
3859 from induction variable CAND. If ADDRESS_P is true, we just need
3860 to create an address from it, otherwise we want to get it into
3861 register. A set of invariants we depend on is stored in
3865 get_computation_cost (struct ivopts_data *data,
3866 struct iv_use *use, struct iv_cand *cand,
3867 bool address_p, bitmap *depends_on)
3869 return get_computation_cost_at (data,
3870 use, cand, address_p, depends_on, use->stmt);
3873 /* Determines cost of basing replacement of USE on CAND in a generic
3877 determine_use_iv_cost_generic (struct ivopts_data *data,
3878 struct iv_use *use, struct iv_cand *cand)
3883 /* The simple case first -- if we need to express value of the preserved
3884 original biv, the cost is 0. This also prevents us from counting the
3885 cost of increment twice -- once at this use and once in the cost of
3887 if (cand->pos == IP_ORIGINAL
3888 && cand->incremented_at == use->stmt)
3890 set_use_iv_cost (data, use, cand, 0, NULL, NULL_TREE);
3894 cost = get_computation_cost (data, use, cand, false, &depends_on);
3895 set_use_iv_cost (data, use, cand, cost, depends_on, NULL_TREE);
3897 return cost != INFTY;
3900 /* Determines cost of basing replacement of USE on CAND in an address. */
3903 determine_use_iv_cost_address (struct ivopts_data *data,
3904 struct iv_use *use, struct iv_cand *cand)
3907 unsigned cost = get_computation_cost (data, use, cand, true, &depends_on);
3909 set_use_iv_cost (data, use, cand, cost, depends_on, NULL_TREE);
3911 return cost != INFTY;
3914 /* Computes value of induction variable IV in iteration NITER. */
3917 iv_value (struct iv *iv, tree niter)
3920 tree type = TREE_TYPE (iv->base);
3922 niter = fold_convert (type, niter);
3923 val = fold_build2 (MULT_EXPR, type, iv->step, niter);
3925 return fold_build2 (PLUS_EXPR, type, iv->base, val);
3928 /* Computes value of candidate CAND at position AT in iteration NITER. */
3931 cand_value_at (struct loop *loop, struct iv_cand *cand, tree at, tree niter)
3933 tree val = iv_value (cand->iv, niter);
3934 tree type = TREE_TYPE (cand->iv->base);
3936 if (stmt_after_increment (loop, cand, at))
3937 val = fold_build2 (PLUS_EXPR, type, val, cand->iv->step);
3942 /* Returns period of induction variable iv. */
3945 iv_period (struct iv *iv)
3947 tree step = iv->step, period, type;
3950 gcc_assert (step && TREE_CODE (step) == INTEGER_CST);
3952 /* Period of the iv is gcd (step, type range). Since type range is power
3953 of two, it suffices to determine the maximum power of two that divides
3955 pow2div = num_ending_zeros (step);
3956 type = unsigned_type_for (TREE_TYPE (step));
3958 period = build_low_bits_mask (type,
3959 (TYPE_PRECISION (type)
3960 - tree_low_cst (pow2div, 1)));
3965 /* Returns the comparison operator used when eliminating the iv USE. */
3967 static enum tree_code
3968 iv_elimination_compare (struct ivopts_data *data, struct iv_use *use)
3970 struct loop *loop = data->current_loop;
3974 ex_bb = bb_for_stmt (use->stmt);
3975 exit = EDGE_SUCC (ex_bb, 0);
3976 if (flow_bb_inside_loop_p (loop, exit->dest))
3977 exit = EDGE_SUCC (ex_bb, 1);
3979 return (exit->flags & EDGE_TRUE_VALUE ? EQ_EXPR : NE_EXPR);
3982 /* Check whether it is possible to express the condition in USE by comparison
3983 of candidate CAND. If so, store the value compared with to BOUND. */
3986 may_eliminate_iv (struct ivopts_data *data,
3987 struct iv_use *use, struct iv_cand *cand, tree *bound)
3991 struct tree_niter_desc *niter;
3993 tree wider_type, period, per_type;
3994 struct loop *loop = data->current_loop;
3996 if (TREE_CODE (cand->iv->step) != INTEGER_CST)
3999 /* For now works only for exits that dominate the loop latch. TODO -- extend
4000 for other conditions inside loop body. */
4001 ex_bb = bb_for_stmt (use->stmt);
4002 if (use->stmt != last_stmt (ex_bb)
4003 || TREE_CODE (use->stmt) != COND_EXPR)
4005 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, ex_bb))
4008 exit = EDGE_SUCC (ex_bb, 0);
4009 if (flow_bb_inside_loop_p (loop, exit->dest))
4010 exit = EDGE_SUCC (ex_bb, 1);
4011 if (flow_bb_inside_loop_p (loop, exit->dest))
4014 niter = niter_for_exit (data, exit);
4016 || !zero_p (niter->may_be_zero))
4020 nit_type = TREE_TYPE (nit);
4022 /* Determine whether we may use the variable to test whether niter iterations
4023 elapsed. This is the case iff the period of the induction variable is
4024 greater than the number of iterations. */
4025 period = iv_period (cand->iv);
4028 per_type = TREE_TYPE (period);
4030 wider_type = TREE_TYPE (period);
4031 if (TYPE_PRECISION (nit_type) < TYPE_PRECISION (per_type))
4032 wider_type = per_type;
4034 wider_type = nit_type;
4036 if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node,
4037 fold_convert (wider_type, period),
4038 fold_convert (wider_type, nit))))
4041 *bound = cand_value_at (loop, cand, use->stmt, nit);
4045 /* Determines cost of basing replacement of USE on CAND in a condition. */
4048 determine_use_iv_cost_condition (struct ivopts_data *data,
4049 struct iv_use *use, struct iv_cand *cand)
4051 tree bound = NULL_TREE, op, cond;
4052 bitmap depends_on = NULL;
4055 /* Only consider real candidates. */
4058 set_use_iv_cost (data, use, cand, INFTY, NULL, NULL_TREE);
4062 if (may_eliminate_iv (data, use, cand, &bound))
4064 cost = force_var_cost (data, bound, &depends_on);
4066 set_use_iv_cost (data, use, cand, cost, depends_on, bound);
4067 return cost != INFTY;
4070 /* The induction variable elimination failed; just express the original
4071 giv. If it is compared with an invariant, note that we cannot get
4073 cost = get_computation_cost (data, use, cand, false, &depends_on);
4076 if (TREE_CODE (cond) != SSA_NAME)
4078 op = TREE_OPERAND (cond, 0);
4079 if (TREE_CODE (op) == SSA_NAME && !zero_p (get_iv (data, op)->step))
4080 op = TREE_OPERAND (cond, 1);
4081 if (TREE_CODE (op) == SSA_NAME)
4083 op = get_iv (data, op)->base;
4084 fd_ivopts_data = data;
4085 walk_tree (&op, find_depends, &depends_on, NULL);
4089 set_use_iv_cost (data, use, cand, cost, depends_on, NULL);
4090 return cost != INFTY;
4093 /* Checks whether it is possible to replace the final value of USE by
4094 a direct computation. If so, the formula is stored to *VALUE. */
4097 may_replace_final_value (struct ivopts_data *data, struct iv_use *use,
4100 struct loop *loop = data->current_loop;
4102 struct tree_niter_desc *niter;
4104 exit = single_dom_exit (loop);
4108 gcc_assert (dominated_by_p (CDI_DOMINATORS, exit->src,
4109 bb_for_stmt (use->stmt)));
4111 niter = niter_for_single_dom_exit (data);
4113 || !zero_p (niter->may_be_zero))
4116 *value = iv_value (use->iv, niter->niter);
4121 /* Determines cost of replacing final value of USE using CAND. */
4124 determine_use_iv_cost_outer (struct ivopts_data *data,
4125 struct iv_use *use, struct iv_cand *cand)
4130 tree value = NULL_TREE;
4131 struct loop *loop = data->current_loop;
4133 /* The simple case first -- if we need to express value of the preserved
4134 original biv, the cost is 0. This also prevents us from counting the
4135 cost of increment twice -- once at this use and once in the cost of
4137 if (cand->pos == IP_ORIGINAL
4138 && cand->incremented_at == use->stmt)
4140 set_use_iv_cost (data, use, cand, 0, NULL, NULL_TREE);
4146 if (!may_replace_final_value (data, use, &value))
4148 set_use_iv_cost (data, use, cand, INFTY, NULL, NULL_TREE);
4153 cost = force_var_cost (data, value, &depends_on);
4155 cost /= AVG_LOOP_NITER (loop);
4157 set_use_iv_cost (data, use, cand, cost, depends_on, value);
4158 return cost != INFTY;
4161 exit = single_dom_exit (loop);
4164 /* If there is just a single exit, we may use value of the candidate
4165 after we take it to determine the value of use. */
4166 cost = get_computation_cost_at (data, use, cand, false, &depends_on,
4167 last_stmt (exit->src));
4169 cost /= AVG_LOOP_NITER (loop);
4173 /* Otherwise we just need to compute the iv. */
4174 cost = get_computation_cost (data, use, cand, false, &depends_on);
4177 set_use_iv_cost (data, use, cand, cost, depends_on, NULL_TREE);
4179 return cost != INFTY;
4182 /* Determines cost of basing replacement of USE on CAND. Returns false
4183 if USE cannot be based on CAND. */
4186 determine_use_iv_cost (struct ivopts_data *data,
4187 struct iv_use *use, struct iv_cand *cand)
4191 case USE_NONLINEAR_EXPR:
4192 return determine_use_iv_cost_generic (data, use, cand);
4195 return determine_use_iv_cost_outer (data, use, cand);
4198 return determine_use_iv_cost_address (data, use, cand);
4201 return determine_use_iv_cost_condition (data, use, cand);
4208 /* Determines costs of basing the use of the iv on an iv candidate. */
4211 determine_use_iv_costs (struct ivopts_data *data)
4215 struct iv_cand *cand;
4216 bitmap to_clear = BITMAP_ALLOC (NULL);
4218 alloc_use_cost_map (data);
4220 for (i = 0; i < n_iv_uses (data); i++)
4222 use = iv_use (data, i);
4224 if (data->consider_all_candidates)
4226 for (j = 0; j < n_iv_cands (data); j++)
4228 cand = iv_cand (data, j);
4229 determine_use_iv_cost (data, use, cand);
4236 EXECUTE_IF_SET_IN_BITMAP (use->related_cands, 0, j, bi)
4238 cand = iv_cand (data, j);
4239 if (!determine_use_iv_cost (data, use, cand))
4240 bitmap_set_bit (to_clear, j);
4243 /* Remove the candidates for that the cost is infinite from
4244 the list of related candidates. */
4245 bitmap_and_compl_into (use->related_cands, to_clear);
4246 bitmap_clear (to_clear);
4250 BITMAP_FREE (to_clear);
4252 if (dump_file && (dump_flags & TDF_DETAILS))
4254 fprintf (dump_file, "Use-candidate costs:\n");
4256 for (i = 0; i < n_iv_uses (data); i++)
4258 use = iv_use (data, i);
4260 fprintf (dump_file, "Use %d:\n", i);
4261 fprintf (dump_file, " cand\tcost\tdepends on\n");
4262 for (j = 0; j < use->n_map_members; j++)
4264 if (!use->cost_map[j].cand
4265 || use->cost_map[j].cost == INFTY)
4268 fprintf (dump_file, " %d\t%d\t",
4269 use->cost_map[j].cand->id,
4270 use->cost_map[j].cost);
4271 if (use->cost_map[j].depends_on)
4272 bitmap_print (dump_file,
4273 use->cost_map[j].depends_on, "","");
4274 fprintf (dump_file, "\n");
4277 fprintf (dump_file, "\n");
4279 fprintf (dump_file, "\n");
4283 /* Determines cost of the candidate CAND. */
4286 determine_iv_cost (struct ivopts_data *data, struct iv_cand *cand)
4288 unsigned cost_base, cost_step;
4297 /* There are two costs associated with the candidate -- its increment
4298 and its initialization. The second is almost negligible for any loop
4299 that rolls enough, so we take it just very little into account. */
4301 base = cand->iv->base;
4302 cost_base = force_var_cost (data, base, NULL);
4303 cost_step = add_cost (TYPE_MODE (TREE_TYPE (base)));
4305 cand->cost = cost_step + cost_base / AVG_LOOP_NITER (current_loop);
4307 /* Prefer the original iv unless we may gain something by replacing it;
4308 this is not really relevant for artificial ivs created by other
4310 if (cand->pos == IP_ORIGINAL
4311 && !DECL_ARTIFICIAL (SSA_NAME_VAR (cand->var_before)))
4314 /* Prefer not to insert statements into latch unless there are some
4315 already (so that we do not create unnecessary jumps). */
4316 if (cand->pos == IP_END
4317 && empty_block_p (ip_end_pos (data->current_loop)))
4321 /* Determines costs of computation of the candidates. */
4324 determine_iv_costs (struct ivopts_data *data)
4328 if (dump_file && (dump_flags & TDF_DETAILS))
4330 fprintf (dump_file, "Candidate costs:\n");
4331 fprintf (dump_file, " cand\tcost\n");
4334 for (i = 0; i < n_iv_cands (data); i++)
4336 struct iv_cand *cand = iv_cand (data, i);
4338 determine_iv_cost (data, cand);
4340 if (dump_file && (dump_flags & TDF_DETAILS))
4341 fprintf (dump_file, " %d\t%d\n", i, cand->cost);
4344 if (dump_file && (dump_flags & TDF_DETAILS))
4345 fprintf (dump_file, "\n");
4348 /* Calculates cost for having SIZE induction variables. */
4351 ivopts_global_cost_for_size (struct ivopts_data *data, unsigned size)
4353 return global_cost_for_size (size,
4354 loop_data (data->current_loop)->regs_used,
4358 /* For each size of the induction variable set determine the penalty. */
4361 determine_set_costs (struct ivopts_data *data)
4365 struct loop *loop = data->current_loop;
4368 /* We use the following model (definitely improvable, especially the
4369 cost function -- TODO):
4371 We estimate the number of registers available (using MD data), name it A.
4373 We estimate the number of registers used by the loop, name it U. This
4374 number is obtained as the number of loop phi nodes (not counting virtual
4375 registers and bivs) + the number of variables from outside of the loop.
4377 We set a reserve R (free regs that are used for temporary computations,
4378 etc.). For now the reserve is a constant 3.
4380 Let I be the number of induction variables.
4382 -- if U + I + R <= A, the cost is I * SMALL_COST (just not to encourage
4383 make a lot of ivs without a reason).
4384 -- if A - R < U + I <= A, the cost is I * PRES_COST
4385 -- if U + I > A, the cost is I * PRES_COST and
4386 number of uses * SPILL_COST * (U + I - A) / (U + I) is added. */
4388 if (dump_file && (dump_flags & TDF_DETAILS))
4390 fprintf (dump_file, "Global costs:\n");
4391 fprintf (dump_file, " target_avail_regs %d\n", target_avail_regs);
4392 fprintf (dump_file, " target_small_cost %d\n", target_small_cost);
4393 fprintf (dump_file, " target_pres_cost %d\n", target_pres_cost);
4394 fprintf (dump_file, " target_spill_cost %d\n", target_spill_cost);
4398 for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi))
4400 op = PHI_RESULT (phi);
4402 if (!is_gimple_reg (op))
4405 if (get_iv (data, op))
4411 EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, j, bi)
4413 struct version_info *info = ver_info (data, j);
4415 if (info->inv_id && info->has_nonlin_use)
4419 loop_data (loop)->regs_used = n;
4420 if (dump_file && (dump_flags & TDF_DETAILS))
4421 fprintf (dump_file, " regs_used %d\n", n);
4423 if (dump_file && (dump_flags & TDF_DETAILS))
4425 fprintf (dump_file, " cost for size:\n");
4426 fprintf (dump_file, " ivs\tcost\n");
4427 for (j = 0; j <= 2 * target_avail_regs; j++)
4428 fprintf (dump_file, " %d\t%d\n", j,
4429 ivopts_global_cost_for_size (data, j));
4430 fprintf (dump_file, "\n");
4434 /* Returns true if A is a cheaper cost pair than B. */
4437 cheaper_cost_pair (struct cost_pair *a, struct cost_pair *b)
4445 if (a->cost < b->cost)
4448 if (a->cost > b->cost)
4451 /* In case the costs are the same, prefer the cheaper candidate. */
4452 if (a->cand->cost < b->cand->cost)
4458 /* Computes the cost field of IVS structure. */
4461 iv_ca_recount_cost (struct ivopts_data *data, struct iv_ca *ivs)
4465 cost += ivs->cand_use_cost;
4466 cost += ivs->cand_cost;
4467 cost += ivopts_global_cost_for_size (data, ivs->n_regs);
4472 /* Remove invariants in set INVS to set IVS. */
4475 iv_ca_set_remove_invariants (struct iv_ca *ivs, bitmap invs)
4483 EXECUTE_IF_SET_IN_BITMAP (invs, 0, iid, bi)
4485 ivs->n_invariant_uses[iid]--;
4486 if (ivs->n_invariant_uses[iid] == 0)
4491 /* Set USE not to be expressed by any candidate in IVS. */
4494 iv_ca_set_no_cp (struct ivopts_data *data, struct iv_ca *ivs,
4497 unsigned uid = use->id, cid;
4498 struct cost_pair *cp;
4500 cp = ivs->cand_for_use[uid];
4506 ivs->cand_for_use[uid] = NULL;
4507 ivs->n_cand_uses[cid]--;
4509 if (ivs->n_cand_uses[cid] == 0)
4511 bitmap_clear_bit (ivs->cands, cid);
4512 /* Do not count the pseudocandidates. */
4516 ivs->cand_cost -= cp->cand->cost;
4518 iv_ca_set_remove_invariants (ivs, cp->cand->depends_on);
4521 ivs->cand_use_cost -= cp->cost;
4523 iv_ca_set_remove_invariants (ivs, cp->depends_on);
4524 iv_ca_recount_cost (data, ivs);
4527 /* Add invariants in set INVS to set IVS. */
4530 iv_ca_set_add_invariants (struct iv_ca *ivs, bitmap invs)
4538 EXECUTE_IF_SET_IN_BITMAP (invs, 0, iid, bi)
4540 ivs->n_invariant_uses[iid]++;
4541 if (ivs->n_invariant_uses[iid] == 1)
4546 /* Set cost pair for USE in set IVS to CP. */
4549 iv_ca_set_cp (struct ivopts_data *data, struct iv_ca *ivs,
4550 struct iv_use *use, struct cost_pair *cp)
4552 unsigned uid = use->id, cid;
4554 if (ivs->cand_for_use[uid] == cp)
4557 if (ivs->cand_for_use[uid])
4558 iv_ca_set_no_cp (data, ivs, use);
4565 ivs->cand_for_use[uid] = cp;
4566 ivs->n_cand_uses[cid]++;
4567 if (ivs->n_cand_uses[cid] == 1)
4569 bitmap_set_bit (ivs->cands, cid);
4570 /* Do not count the pseudocandidates. */
4574 ivs->cand_cost += cp->cand->cost;
4576 iv_ca_set_add_invariants (ivs, cp->cand->depends_on);
4579 ivs->cand_use_cost += cp->cost;
4580 iv_ca_set_add_invariants (ivs, cp->depends_on);
4581 iv_ca_recount_cost (data, ivs);
4585 /* Extend set IVS by expressing USE by some of the candidates in it
4589 iv_ca_add_use (struct ivopts_data *data, struct iv_ca *ivs,
4592 struct cost_pair *best_cp = NULL, *cp;
4596 gcc_assert (ivs->upto >= use->id);
4598 if (ivs->upto == use->id)
4604 EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, i, bi)
4606 cp = get_use_iv_cost (data, use, iv_cand (data, i));
4608 if (cheaper_cost_pair (cp, best_cp))
4612 iv_ca_set_cp (data, ivs, use, best_cp);
4615 /* Get cost for assignment IVS. */
4618 iv_ca_cost (struct iv_ca *ivs)
4620 return (ivs->bad_uses ? INFTY : ivs->cost);
4623 /* Returns true if all dependences of CP are among invariants in IVS. */
4626 iv_ca_has_deps (struct iv_ca *ivs, struct cost_pair *cp)
4631 if (!cp->depends_on)
4634 EXECUTE_IF_SET_IN_BITMAP (cp->depends_on, 0, i, bi)
4636 if (ivs->n_invariant_uses[i] == 0)
4643 /* Creates change of expressing USE by NEW_CP instead of OLD_CP and chains
4644 it before NEXT_CHANGE. */
4646 static struct iv_ca_delta *
4647 iv_ca_delta_add (struct iv_use *use, struct cost_pair *old_cp,
4648 struct cost_pair *new_cp, struct iv_ca_delta *next_change)
4650 struct iv_ca_delta *change = xmalloc (sizeof (struct iv_ca_delta));
4653 change->old_cp = old_cp;
4654 change->new_cp = new_cp;
4655 change->next_change = next_change;
4660 /* Joins two lists of changes L1 and L2. Destructive -- old lists
4663 static struct iv_ca_delta *
4664 iv_ca_delta_join (struct iv_ca_delta *l1, struct iv_ca_delta *l2)
4666 struct iv_ca_delta *last;
4674 for (last = l1; last->next_change; last = last->next_change)
4676 last->next_change = l2;
4681 /* Returns candidate by that USE is expressed in IVS. */
4683 static struct cost_pair *
4684 iv_ca_cand_for_use (struct iv_ca *ivs, struct iv_use *use)
4686 return ivs->cand_for_use[use->id];
4689 /* Reverse the list of changes DELTA, forming the inverse to it. */
4691 static struct iv_ca_delta *
4692 iv_ca_delta_reverse (struct iv_ca_delta *delta)
4694 struct iv_ca_delta *act, *next, *prev = NULL;
4695 struct cost_pair *tmp;
4697 for (act = delta; act; act = next)
4699 next = act->next_change;
4700 act->next_change = prev;
4704 act->old_cp = act->new_cp;
4711 /* Commit changes in DELTA to IVS. If FORWARD is false, the changes are
4712 reverted instead. */
4715 iv_ca_delta_commit (struct ivopts_data *data, struct iv_ca *ivs,
4716 struct iv_ca_delta *delta, bool forward)
4718 struct cost_pair *from, *to;
4719 struct iv_ca_delta *act;
4722 delta = iv_ca_delta_reverse (delta);
4724 for (act = delta; act; act = act->next_change)
4728 gcc_assert (iv_ca_cand_for_use (ivs, act->use) == from);
4729 iv_ca_set_cp (data, ivs, act->use, to);
4733 iv_ca_delta_reverse (delta);
4736 /* Returns true if CAND is used in IVS. */
4739 iv_ca_cand_used_p (struct iv_ca *ivs, struct iv_cand *cand)
4741 return ivs->n_cand_uses[cand->id] > 0;
4744 /* Returns number of induction variable candidates in the set IVS. */
4747 iv_ca_n_cands (struct iv_ca *ivs)
4749 return ivs->n_cands;
4752 /* Free the list of changes DELTA. */
4755 iv_ca_delta_free (struct iv_ca_delta **delta)
4757 struct iv_ca_delta *act, *next;
4759 for (act = *delta; act; act = next)
4761 next = act->next_change;
4768 /* Allocates new iv candidates assignment. */
4770 static struct iv_ca *
4771 iv_ca_new (struct ivopts_data *data)
4773 struct iv_ca *nw = xmalloc (sizeof (struct iv_ca));
4777 nw->cand_for_use = xcalloc (n_iv_uses (data), sizeof (struct cost_pair *));
4778 nw->n_cand_uses = xcalloc (n_iv_cands (data), sizeof (unsigned));
4779 nw->cands = BITMAP_ALLOC (NULL);
4782 nw->cand_use_cost = 0;
4784 nw->n_invariant_uses = xcalloc (data->max_inv_id + 1, sizeof (unsigned));
4790 /* Free memory occupied by the set IVS. */
4793 iv_ca_free (struct iv_ca **ivs)
4795 free ((*ivs)->cand_for_use);
4796 free ((*ivs)->n_cand_uses);
4797 BITMAP_FREE ((*ivs)->cands);
4798 free ((*ivs)->n_invariant_uses);
4803 /* Dumps IVS to FILE. */
4806 iv_ca_dump (struct ivopts_data *data, FILE *file, struct iv_ca *ivs)
4808 const char *pref = " invariants ";
4811 fprintf (file, " cost %d\n", iv_ca_cost (ivs));
4812 bitmap_print (file, ivs->cands, " candidates ","\n");
4814 for (i = 1; i <= data->max_inv_id; i++)
4815 if (ivs->n_invariant_uses[i])
4817 fprintf (file, "%s%d", pref, i);
4820 fprintf (file, "\n");
4823 /* Try changing candidate in IVS to CAND for each use. Return cost of the
4824 new set, and store differences in DELTA. Number of induction variables
4825 in the new set is stored to N_IVS. */
4828 iv_ca_extend (struct ivopts_data *data, struct iv_ca *ivs,
4829 struct iv_cand *cand, struct iv_ca_delta **delta,
4834 struct cost_pair *old_cp, *new_cp;
4837 for (i = 0; i < ivs->upto; i++)
4839 use = iv_use (data, i);
4840 old_cp = iv_ca_cand_for_use (ivs, use);
4843 && old_cp->cand == cand)
4846 new_cp = get_use_iv_cost (data, use, cand);
4850 if (!iv_ca_has_deps (ivs, new_cp))
4853 if (!cheaper_cost_pair (new_cp, old_cp))
4856 *delta = iv_ca_delta_add (use, old_cp, new_cp, *delta);
4859 iv_ca_delta_commit (data, ivs, *delta, true);
4860 cost = iv_ca_cost (ivs);
4862 *n_ivs = iv_ca_n_cands (ivs);
4863 iv_ca_delta_commit (data, ivs, *delta, false);
4868 /* Try narrowing set IVS by removing CAND. Return the cost of
4869 the new set and store the differences in DELTA. */
4872 iv_ca_narrow (struct ivopts_data *data, struct iv_ca *ivs,
4873 struct iv_cand *cand, struct iv_ca_delta **delta)
4877 struct cost_pair *old_cp, *new_cp, *cp;
4879 struct iv_cand *cnd;
4883 for (i = 0; i < n_iv_uses (data); i++)
4885 use = iv_use (data, i);
4887 old_cp = iv_ca_cand_for_use (ivs, use);
4888 if (old_cp->cand != cand)
4893 if (data->consider_all_candidates)
4895 EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, ci, bi)
4900 cnd = iv_cand (data, ci);
4902 cp = get_use_iv_cost (data, use, cnd);
4905 if (!iv_ca_has_deps (ivs, cp))
4908 if (!cheaper_cost_pair (cp, new_cp))
4916 EXECUTE_IF_AND_IN_BITMAP (use->related_cands, ivs->cands, 0, ci, bi)
4921 cnd = iv_cand (data, ci);
4923 cp = get_use_iv_cost (data, use, cnd);
4926 if (!iv_ca_has_deps (ivs, cp))
4929 if (!cheaper_cost_pair (cp, new_cp))
4938 iv_ca_delta_free (delta);
4942 *delta = iv_ca_delta_add (use, old_cp, new_cp, *delta);
4945 iv_ca_delta_commit (data, ivs, *delta, true);
4946 cost = iv_ca_cost (ivs);
4947 iv_ca_delta_commit (data, ivs, *delta, false);
4952 /* Try optimizing the set of candidates IVS by removing candidates different
4953 from to EXCEPT_CAND from it. Return cost of the new set, and store
4954 differences in DELTA. */
4957 iv_ca_prune (struct ivopts_data *data, struct iv_ca *ivs,
4958 struct iv_cand *except_cand, struct iv_ca_delta **delta)
4961 struct iv_ca_delta *act_delta, *best_delta;
4962 unsigned i, best_cost, acost;
4963 struct iv_cand *cand;
4966 best_cost = iv_ca_cost (ivs);
4968 EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, i, bi)
4970 cand = iv_cand (data, i);
4972 if (cand == except_cand)
4975 acost = iv_ca_narrow (data, ivs, cand, &act_delta);
4977 if (acost < best_cost)
4980 iv_ca_delta_free (&best_delta);
4981 best_delta = act_delta;
4984 iv_ca_delta_free (&act_delta);
4993 /* Recurse to possibly remove other unnecessary ivs. */
4994 iv_ca_delta_commit (data, ivs, best_delta, true);
4995 best_cost = iv_ca_prune (data, ivs, except_cand, delta);
4996 iv_ca_delta_commit (data, ivs, best_delta, false);
4997 *delta = iv_ca_delta_join (best_delta, *delta);
5001 /* Tries to extend the sets IVS in the best possible way in order
5002 to express the USE. */
5005 try_add_cand_for (struct ivopts_data *data, struct iv_ca *ivs,
5008 unsigned best_cost, act_cost;
5011 struct iv_cand *cand;
5012 struct iv_ca_delta *best_delta = NULL, *act_delta;
5013 struct cost_pair *cp;
5015 iv_ca_add_use (data, ivs, use);
5016 best_cost = iv_ca_cost (ivs);
5018 cp = iv_ca_cand_for_use (ivs, use);
5021 best_delta = iv_ca_delta_add (use, NULL, cp, NULL);
5022 iv_ca_set_no_cp (data, ivs, use);
5025 /* First try important candidates. Only if it fails, try the specific ones.
5026 Rationale -- in loops with many variables the best choice often is to use
5027 just one generic biv. If we added here many ivs specific to the uses,
5028 the optimization algorithm later would be likely to get stuck in a local
5029 minimum, thus causing us to create too many ivs. The approach from
5030 few ivs to more seems more likely to be successful -- starting from few
5031 ivs, replacing an expensive use by a specific iv should always be a
5033 EXECUTE_IF_SET_IN_BITMAP (data->important_candidates, 0, i, bi)
5035 cand = iv_cand (data, i);
5037 if (iv_ca_cand_used_p (ivs, cand))
5040 cp = get_use_iv_cost (data, use, cand);
5044 iv_ca_set_cp (data, ivs, use, cp);
5045 act_cost = iv_ca_extend (data, ivs, cand, &act_delta, NULL);
5046 iv_ca_set_no_cp (data, ivs, use);
5047 act_delta = iv_ca_delta_add (use, NULL, cp, act_delta);
5049 if (act_cost < best_cost)
5051 best_cost = act_cost;
5053 iv_ca_delta_free (&best_delta);
5054 best_delta = act_delta;
5057 iv_ca_delta_free (&act_delta);
5060 if (best_cost == INFTY)
5062 for (i = 0; i < use->n_map_members; i++)
5064 cp = use->cost_map + i;
5069 /* Already tried this. */
5070 if (cand->important)
5073 if (iv_ca_cand_used_p (ivs, cand))
5077 iv_ca_set_cp (data, ivs, use, cp);
5078 act_cost = iv_ca_extend (data, ivs, cand, &act_delta, NULL);
5079 iv_ca_set_no_cp (data, ivs, use);
5080 act_delta = iv_ca_delta_add (use, iv_ca_cand_for_use (ivs, use),
5083 if (act_cost < best_cost)
5085 best_cost = act_cost;
5088 iv_ca_delta_free (&best_delta);
5089 best_delta = act_delta;
5092 iv_ca_delta_free (&act_delta);
5096 iv_ca_delta_commit (data, ivs, best_delta, true);
5097 iv_ca_delta_free (&best_delta);
5099 return (best_cost != INFTY);
5102 /* Finds an initial assignment of candidates to uses. */
5104 static struct iv_ca *
5105 get_initial_solution (struct ivopts_data *data)
5107 struct iv_ca *ivs = iv_ca_new (data);
5110 for (i = 0; i < n_iv_uses (data); i++)
5111 if (!try_add_cand_for (data, ivs, iv_use (data, i)))
5120 /* Tries to improve set of induction variables IVS. */
5123 try_improve_iv_set (struct ivopts_data *data, struct iv_ca *ivs)
5125 unsigned i, acost, best_cost = iv_ca_cost (ivs), n_ivs;
5126 struct iv_ca_delta *best_delta = NULL, *act_delta, *tmp_delta;
5127 struct iv_cand *cand;
5129 /* Try extending the set of induction variables by one. */
5130 for (i = 0; i < n_iv_cands (data); i++)
5132 cand = iv_cand (data, i);
5134 if (iv_ca_cand_used_p (ivs, cand))
5137 acost = iv_ca_extend (data, ivs, cand, &act_delta, &n_ivs);
5141 /* If we successfully added the candidate and the set is small enough,
5142 try optimizing it by removing other candidates. */
5143 if (n_ivs <= ALWAYS_PRUNE_CAND_SET_BOUND)
5145 iv_ca_delta_commit (data, ivs, act_delta, true);
5146 acost = iv_ca_prune (data, ivs, cand, &tmp_delta);
5147 iv_ca_delta_commit (data, ivs, act_delta, false);
5148 act_delta = iv_ca_delta_join (act_delta, tmp_delta);
5151 if (acost < best_cost)
5154 iv_ca_delta_free (&best_delta);
5155 best_delta = act_delta;
5158 iv_ca_delta_free (&act_delta);
5163 /* Try removing the candidates from the set instead. */
5164 best_cost = iv_ca_prune (data, ivs, NULL, &best_delta);
5166 /* Nothing more we can do. */
5171 iv_ca_delta_commit (data, ivs, best_delta, true);
5172 gcc_assert (best_cost == iv_ca_cost (ivs));
5173 iv_ca_delta_free (&best_delta);
5177 /* Attempts to find the optimal set of induction variables. We do simple
5178 greedy heuristic -- we try to replace at most one candidate in the selected
5179 solution and remove the unused ivs while this improves the cost. */
5181 static struct iv_ca *
5182 find_optimal_iv_set (struct ivopts_data *data)
5188 /* Get the initial solution. */
5189 set = get_initial_solution (data);
5192 if (dump_file && (dump_flags & TDF_DETAILS))
5193 fprintf (dump_file, "Unable to substitute for ivs, failed.\n");
5197 if (dump_file && (dump_flags & TDF_DETAILS))
5199 fprintf (dump_file, "Initial set of candidates:\n");
5200 iv_ca_dump (data, dump_file, set);
5203 while (try_improve_iv_set (data, set))
5205 if (dump_file && (dump_flags & TDF_DETAILS))
5207 fprintf (dump_file, "Improved to:\n");
5208 iv_ca_dump (data, dump_file, set);
5212 if (dump_file && (dump_flags & TDF_DETAILS))
5213 fprintf (dump_file, "Final cost %d\n\n", iv_ca_cost (set));
5215 for (i = 0; i < n_iv_uses (data); i++)
5217 use = iv_use (data, i);
5218 use->selected = iv_ca_cand_for_use (set, use)->cand;
5224 /* Creates a new induction variable corresponding to CAND. */
5227 create_new_iv (struct ivopts_data *data, struct iv_cand *cand)
5229 block_stmt_iterator incr_pos;
5239 incr_pos = bsi_last (ip_normal_pos (data->current_loop));
5243 incr_pos = bsi_last (ip_end_pos (data->current_loop));
5248 /* Mark that the iv is preserved. */
5249 name_info (data, cand->var_before)->preserve_biv = true;
5250 name_info (data, cand->var_after)->preserve_biv = true;
5252 /* Rewrite the increment so that it uses var_before directly. */
5253 find_interesting_uses_op (data, cand->var_after)->selected = cand;
5258 gimple_add_tmp_var (cand->var_before);
5259 add_referenced_tmp_var (cand->var_before);
5261 base = unshare_expr (cand->iv->base);
5263 create_iv (base, unshare_expr (cand->iv->step),
5264 cand->var_before, data->current_loop,
5265 &incr_pos, after, &cand->var_before, &cand->var_after);
5268 /* Creates new induction variables described in SET. */
5271 create_new_ivs (struct ivopts_data *data, struct iv_ca *set)
5274 struct iv_cand *cand;
5277 EXECUTE_IF_SET_IN_BITMAP (set->cands, 0, i, bi)
5279 cand = iv_cand (data, i);
5280 create_new_iv (data, cand);
5284 /* Removes statement STMT (real or a phi node). If INCLUDING_DEFINED_NAME
5285 is true, remove also the ssa name defined by the statement. */
5288 remove_statement (tree stmt, bool including_defined_name)
5290 if (TREE_CODE (stmt) == PHI_NODE)
5292 if (!including_defined_name)
5294 /* Prevent the ssa name defined by the statement from being removed. */
5295 SET_PHI_RESULT (stmt, NULL);
5297 remove_phi_node (stmt, NULL_TREE);
5301 block_stmt_iterator bsi = bsi_for_stmt (stmt);
5307 /* Rewrites USE (definition of iv used in a nonlinear expression)
5308 using candidate CAND. */
5311 rewrite_use_nonlinear_expr (struct ivopts_data *data,
5312 struct iv_use *use, struct iv_cand *cand)
5315 tree op, stmts, tgt, ass;
5316 block_stmt_iterator bsi, pbsi;
5318 /* An important special case -- if we are asked to express value of
5319 the original iv by itself, just exit; there is no need to
5320 introduce a new computation (that might also need casting the
5321 variable to unsigned and back). */
5322 if (cand->pos == IP_ORIGINAL
5323 && TREE_CODE (use->stmt) == MODIFY_EXPR
5324 && TREE_OPERAND (use->stmt, 0) == cand->var_after)
5326 op = TREE_OPERAND (use->stmt, 1);
5328 /* Be a bit careful. In case variable is expressed in some
5329 complicated way, rewrite it so that we may get rid of this
5330 complicated expression. */
5331 if ((TREE_CODE (op) == PLUS_EXPR
5332 || TREE_CODE (op) == MINUS_EXPR)
5333 && TREE_OPERAND (op, 0) == cand->var_before
5334 && TREE_CODE (TREE_OPERAND (op, 1)) == INTEGER_CST)
5338 comp = get_computation (data->current_loop, use, cand);
5339 switch (TREE_CODE (use->stmt))
5342 tgt = PHI_RESULT (use->stmt);
5344 /* If we should keep the biv, do not replace it. */
5345 if (name_info (data, tgt)->preserve_biv)
5348 pbsi = bsi = bsi_start (bb_for_stmt (use->stmt));
5349 while (!bsi_end_p (pbsi)
5350 && TREE_CODE (bsi_stmt (pbsi)) == LABEL_EXPR)
5358 tgt = TREE_OPERAND (use->stmt, 0);
5359 bsi = bsi_for_stmt (use->stmt);
5366 op = force_gimple_operand (comp, &stmts, false, SSA_NAME_VAR (tgt));
5368 if (TREE_CODE (use->stmt) == PHI_NODE)
5371 bsi_insert_after (&bsi, stmts, BSI_CONTINUE_LINKING);
5372 ass = build2 (MODIFY_EXPR, TREE_TYPE (tgt), tgt, op);
5373 bsi_insert_after (&bsi, ass, BSI_NEW_STMT);
5374 remove_statement (use->stmt, false);
5375 SSA_NAME_DEF_STMT (tgt) = ass;
5380 bsi_insert_before (&bsi, stmts, BSI_SAME_STMT);
5381 TREE_OPERAND (use->stmt, 1) = op;
5385 /* Replaces ssa name in index IDX by its basic variable. Callback for
5389 idx_remove_ssa_names (tree base, tree *idx,
5390 void *data ATTRIBUTE_UNUSED)
5394 if (TREE_CODE (*idx) == SSA_NAME)
5395 *idx = SSA_NAME_VAR (*idx);
5397 if (TREE_CODE (base) == ARRAY_REF)
5399 op = &TREE_OPERAND (base, 2);
5401 && TREE_CODE (*op) == SSA_NAME)
5402 *op = SSA_NAME_VAR (*op);
5403 op = &TREE_OPERAND (base, 3);
5405 && TREE_CODE (*op) == SSA_NAME)
5406 *op = SSA_NAME_VAR (*op);
5412 /* Unshares REF and replaces ssa names inside it by their basic variables. */
5415 unshare_and_remove_ssa_names (tree ref)
5417 ref = unshare_expr (ref);
5418 for_each_index (&ref, idx_remove_ssa_names, NULL);
5423 /* Extract the alias analysis info for the memory reference REF. There are
5424 several ways how this information may be stored and what precisely is
5425 its semantics depending on the type of the reference, but there always is
5426 somewhere hidden one _DECL node that is used to determine the set of
5427 virtual operands for the reference. The code below deciphers this jungle
5428 and extracts this single useful piece of information. */
5431 get_ref_tag (tree ref)
5433 tree var = get_base_address (ref);
5439 if (TREE_CODE (var) == INDIRECT_REF)
5440 var = TREE_OPERAND (var, 0);
5441 if (TREE_CODE (var) == SSA_NAME)
5443 if (SSA_NAME_PTR_INFO (var))
5445 tag = SSA_NAME_PTR_INFO (var)->name_mem_tag;
5450 var = SSA_NAME_VAR (var);
5455 tag = var_ann (var)->type_mem_tag;
5465 /* Copies the reference information from OLD_REF to NEW_REF. */
5468 copy_ref_info (tree new_ref, tree old_ref)
5470 if (TREE_CODE (old_ref) == TARGET_MEM_REF)
5471 copy_mem_ref_info (new_ref, old_ref);
5474 TMR_TAG (new_ref) = get_ref_tag (old_ref);
5475 TMR_ORIGINAL (new_ref) = unshare_and_remove_ssa_names (old_ref);
5479 /* Rewrites USE (address that is an iv) using candidate CAND. */
5482 rewrite_use_address (struct ivopts_data *data,
5483 struct iv_use *use, struct iv_cand *cand)
5485 struct affine_tree_combination aff;
5486 block_stmt_iterator bsi = bsi_for_stmt (use->stmt);
5489 get_computation_aff (data->current_loop, use, cand, use->stmt, &aff);
5490 unshare_aff_combination (&aff);
5492 ref = create_mem_ref (&bsi, TREE_TYPE (*use->op_p), &aff);
5493 copy_ref_info (ref, *use->op_p);
5497 /* Rewrites USE (the condition such that one of the arguments is an iv) using
5501 rewrite_use_compare (struct ivopts_data *data,
5502 struct iv_use *use, struct iv_cand *cand)
5505 tree *op_p, cond, op, stmts, bound;
5506 block_stmt_iterator bsi = bsi_for_stmt (use->stmt);
5507 enum tree_code compare;
5508 struct cost_pair *cp = get_use_iv_cost (data, use, cand);
5513 tree var = var_at_stmt (data->current_loop, cand, use->stmt);
5514 tree var_type = TREE_TYPE (var);
5516 compare = iv_elimination_compare (data, use);
5517 bound = fold_convert (var_type, bound);
5518 op = force_gimple_operand (unshare_expr (bound), &stmts,
5522 bsi_insert_before (&bsi, stmts, BSI_SAME_STMT);
5524 *use->op_p = build2 (compare, boolean_type_node, var, op);
5525 update_stmt (use->stmt);
5529 /* The induction variable elimination failed; just express the original
5531 comp = get_computation (data->current_loop, use, cand);
5534 op_p = &TREE_OPERAND (cond, 0);
5535 if (TREE_CODE (*op_p) != SSA_NAME
5536 || zero_p (get_iv (data, *op_p)->step))
5537 op_p = &TREE_OPERAND (cond, 1);
5539 op = force_gimple_operand (comp, &stmts, true, SSA_NAME_VAR (*op_p));
5541 bsi_insert_before (&bsi, stmts, BSI_SAME_STMT);
5546 /* Ensure that operand *OP_P may be used at the end of EXIT without
5547 violating loop closed ssa form. */
5550 protect_loop_closed_ssa_form_use (edge exit, use_operand_p op_p)
5553 struct loop *def_loop;
5556 use = USE_FROM_PTR (op_p);
5557 if (TREE_CODE (use) != SSA_NAME)
5560 def_bb = bb_for_stmt (SSA_NAME_DEF_STMT (use));
5564 def_loop = def_bb->loop_father;
5565 if (flow_bb_inside_loop_p (def_loop, exit->dest))
5568 /* Try finding a phi node that copies the value out of the loop. */
5569 for (phi = phi_nodes (exit->dest); phi; phi = PHI_CHAIN (phi))
5570 if (PHI_ARG_DEF_FROM_EDGE (phi, exit) == use)
5575 /* Create such a phi node. */
5576 tree new_name = duplicate_ssa_name (use, NULL);
5578 phi = create_phi_node (new_name, exit->dest);
5579 SSA_NAME_DEF_STMT (new_name) = phi;
5580 add_phi_arg (phi, use, exit);
5583 SET_USE (op_p, PHI_RESULT (phi));
5586 /* Ensure that operands of STMT may be used at the end of EXIT without
5587 violating loop closed ssa form. */
5590 protect_loop_closed_ssa_form (edge exit, tree stmt)
5593 use_operand_p use_p;
5595 FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
5596 protect_loop_closed_ssa_form_use (exit, use_p);
5599 /* STMTS compute a value of a phi argument OP on EXIT of a loop. Arrange things
5600 so that they are emitted on the correct place, and so that the loop closed
5601 ssa form is preserved. */
5604 compute_phi_arg_on_exit (edge exit, tree stmts, tree op)
5606 tree_stmt_iterator tsi;
5607 block_stmt_iterator bsi;
5608 tree phi, stmt, def, next;
5610 if (!single_pred_p (exit->dest))
5611 split_loop_exit_edge (exit);
5613 /* Ensure there is label in exit->dest, so that we can
5615 tree_block_label (exit->dest);
5616 bsi = bsi_after_labels (exit->dest);
5618 if (TREE_CODE (stmts) == STATEMENT_LIST)
5620 for (tsi = tsi_start (stmts); !tsi_end_p (tsi); tsi_next (&tsi))
5622 bsi_insert_after (&bsi, tsi_stmt (tsi), BSI_NEW_STMT);
5623 protect_loop_closed_ssa_form (exit, bsi_stmt (bsi));
5628 bsi_insert_after (&bsi, stmts, BSI_NEW_STMT);
5629 protect_loop_closed_ssa_form (exit, bsi_stmt (bsi));
5635 for (phi = phi_nodes (exit->dest); phi; phi = next)
5637 next = PHI_CHAIN (phi);
5639 if (PHI_ARG_DEF_FROM_EDGE (phi, exit) == op)
5641 def = PHI_RESULT (phi);
5642 remove_statement (phi, false);
5643 stmt = build2 (MODIFY_EXPR, TREE_TYPE (op),
5645 SSA_NAME_DEF_STMT (def) = stmt;
5646 bsi_insert_after (&bsi, stmt, BSI_CONTINUE_LINKING);
5651 /* Rewrites the final value of USE (that is only needed outside of the loop)
5652 using candidate CAND. */
5655 rewrite_use_outer (struct ivopts_data *data,
5656 struct iv_use *use, struct iv_cand *cand)
5659 tree value, op, stmts, tgt;
5662 switch (TREE_CODE (use->stmt))
5665 tgt = PHI_RESULT (use->stmt);
5668 tgt = TREE_OPERAND (use->stmt, 0);
5674 exit = single_dom_exit (data->current_loop);
5680 struct cost_pair *cp = get_use_iv_cost (data, use, cand);
5681 value = unshare_expr (cp->value);
5684 value = get_computation_at (data->current_loop,
5685 use, cand, last_stmt (exit->src));
5687 op = force_gimple_operand (value, &stmts, true, SSA_NAME_VAR (tgt));
5689 /* If we will preserve the iv anyway and we would need to perform
5690 some computation to replace the final value, do nothing. */
5691 if (stmts && name_info (data, tgt)->preserve_biv)
5694 for (phi = phi_nodes (exit->dest); phi; phi = PHI_CHAIN (phi))
5696 use_operand_p use_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, exit);
5698 if (USE_FROM_PTR (use_p) == tgt)
5699 SET_USE (use_p, op);
5703 compute_phi_arg_on_exit (exit, stmts, op);
5705 /* Enable removal of the statement. We cannot remove it directly,
5706 since we may still need the aliasing information attached to the
5707 ssa name defined by it. */
5708 name_info (data, tgt)->iv->have_use_for = false;
5712 /* If the variable is going to be preserved anyway, there is nothing to
5714 if (name_info (data, tgt)->preserve_biv)
5717 /* Otherwise we just need to compute the iv. */
5718 rewrite_use_nonlinear_expr (data, use, cand);
5721 /* Rewrites USE using candidate CAND. */
5724 rewrite_use (struct ivopts_data *data,
5725 struct iv_use *use, struct iv_cand *cand)
5729 case USE_NONLINEAR_EXPR:
5730 rewrite_use_nonlinear_expr (data, use, cand);
5734 rewrite_use_outer (data, use, cand);
5738 rewrite_use_address (data, use, cand);
5742 rewrite_use_compare (data, use, cand);
5748 update_stmt (use->stmt);
5751 /* Rewrite the uses using the selected induction variables. */
5754 rewrite_uses (struct ivopts_data *data)
5757 struct iv_cand *cand;
5760 for (i = 0; i < n_iv_uses (data); i++)
5762 use = iv_use (data, i);
5763 cand = use->selected;
5766 rewrite_use (data, use, cand);
5770 /* Removes the ivs that are not used after rewriting. */
5773 remove_unused_ivs (struct ivopts_data *data)
5778 EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, j, bi)
5780 struct version_info *info;
5782 info = ver_info (data, j);
5784 && !zero_p (info->iv->step)
5786 && !info->iv->have_use_for
5787 && !info->preserve_biv)
5788 remove_statement (SSA_NAME_DEF_STMT (info->iv->ssa_name), true);
5792 /* Frees data allocated by the optimization of a single loop. */
5795 free_loop_data (struct ivopts_data *data)
5801 htab_empty (data->niters);
5803 EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
5805 struct version_info *info;
5807 info = ver_info (data, i);
5811 info->has_nonlin_use = false;
5812 info->preserve_biv = false;
5815 bitmap_clear (data->relevant);
5816 bitmap_clear (data->important_candidates);
5818 for (i = 0; i < n_iv_uses (data); i++)
5820 struct iv_use *use = iv_use (data, i);
5823 BITMAP_FREE (use->related_cands);
5824 for (j = 0; j < use->n_map_members; j++)
5825 if (use->cost_map[j].depends_on)
5826 BITMAP_FREE (use->cost_map[j].depends_on);
5827 free (use->cost_map);
5830 VEC_truncate (iv_use_p, data->iv_uses, 0);
5832 for (i = 0; i < n_iv_cands (data); i++)
5834 struct iv_cand *cand = iv_cand (data, i);
5838 if (cand->depends_on)
5839 BITMAP_FREE (cand->depends_on);
5842 VEC_truncate (iv_cand_p, data->iv_candidates, 0);
5844 if (data->version_info_size < num_ssa_names)
5846 data->version_info_size = 2 * num_ssa_names;
5847 free (data->version_info);
5848 data->version_info = xcalloc (data->version_info_size,
5849 sizeof (struct version_info));
5852 data->max_inv_id = 0;
5854 for (i = 0; VEC_iterate (tree, decl_rtl_to_reset, i, obj); i++)
5855 SET_DECL_RTL (obj, NULL_RTX);
5857 VEC_truncate (tree, decl_rtl_to_reset, 0);
5860 /* Finalizes data structures used by the iv optimization pass. LOOPS is the
5864 tree_ssa_iv_optimize_finalize (struct loops *loops, struct ivopts_data *data)
5868 for (i = 1; i < loops->num; i++)
5869 if (loops->parray[i])
5871 free (loops->parray[i]->aux);
5872 loops->parray[i]->aux = NULL;
5875 free_loop_data (data);
5876 free (data->version_info);
5877 BITMAP_FREE (data->relevant);
5878 BITMAP_FREE (data->important_candidates);
5879 htab_delete (data->niters);
5881 VEC_free (tree, heap, decl_rtl_to_reset);
5882 VEC_free (iv_use_p, heap, data->iv_uses);
5883 VEC_free (iv_cand_p, heap, data->iv_candidates);
5886 /* Optimizes the LOOP. Returns true if anything changed. */
5889 tree_ssa_iv_optimize_loop (struct ivopts_data *data, struct loop *loop)
5891 bool changed = false;
5892 struct iv_ca *iv_ca;
5895 data->current_loop = loop;
5897 if (dump_file && (dump_flags & TDF_DETAILS))
5899 fprintf (dump_file, "Processing loop %d\n", loop->num);
5901 exit = single_dom_exit (loop);
5904 fprintf (dump_file, " single exit %d -> %d, exit condition ",
5905 exit->src->index, exit->dest->index);
5906 print_generic_expr (dump_file, last_stmt (exit->src), TDF_SLIM);
5907 fprintf (dump_file, "\n");
5910 fprintf (dump_file, "\n");
5913 /* For each ssa name determines whether it behaves as an induction variable
5915 if (!find_induction_variables (data))
5918 /* Finds interesting uses (item 1). */
5919 find_interesting_uses (data);
5920 if (n_iv_uses (data) > MAX_CONSIDERED_USES)
5923 /* Finds candidates for the induction variables (item 2). */
5924 find_iv_candidates (data);
5926 /* Calculates the costs (item 3, part 1). */
5927 determine_use_iv_costs (data);
5928 determine_iv_costs (data);
5929 determine_set_costs (data);
5931 /* Find the optimal set of induction variables (item 3, part 2). */
5932 iv_ca = find_optimal_iv_set (data);
5937 /* Create the new induction variables (item 4, part 1). */
5938 create_new_ivs (data, iv_ca);
5939 iv_ca_free (&iv_ca);
5941 /* Rewrite the uses (item 4, part 2). */
5942 rewrite_uses (data);
5944 /* Remove the ivs that are unused after rewriting. */
5945 remove_unused_ivs (data);
5947 /* We have changed the structure of induction variables; it might happen
5948 that definitions in the scev database refer to some of them that were
5953 free_loop_data (data);
5958 /* Main entry point. Optimizes induction variables in LOOPS. */
5961 tree_ssa_iv_optimize (struct loops *loops)
5964 struct ivopts_data data;
5966 tree_ssa_iv_optimize_init (loops, &data);
5968 /* Optimize the loops starting with the innermost ones. */
5969 loop = loops->tree_root;
5973 /* Scan the loops, inner ones first. */
5974 while (loop != loops->tree_root)
5976 if (dump_file && (dump_flags & TDF_DETAILS))
5977 flow_loop_dump (loop, dump_file, NULL, 1);
5979 tree_ssa_iv_optimize_loop (&data, loop);
5991 tree_ssa_iv_optimize_finalize (loops, &data);